drivers/md/raid5.c

   1 /*
   2  * raid5.c : Multiple Devices driver for Linux
   3  *         Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
   4  *         Copyright (C) 1999, 2000 Ingo Molnar
   5  *         Copyright (C) 2002, 2003 H. Peter Anvin
   6  *
   7  * RAID-4/5/6 management functions.
   8  * Thanks to Penguin Computing for making the RAID-6 development possible
   9  * by donating a test server!
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2, or (at your option)
  14  * any later version.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * (for example /usr/src/linux/COPYING); if not, write to the Free
  18  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20
  21 /*
  22  * BITMAP UNPLUGGING:
  23  *
  24  * The sequencing for updating the bitmap reliably is a little
  25  * subtle (and I got it wrong the first time) so it deserves some
  26  * explanation.
  27  *
  28  * We group bitmap updates into batches.  Each batch has a number.
  29  * We may write out several batches at once, but that isn't very important.
  30  * conf->seq_write is the number of the last batch successfully written.
  31  * conf->seq_flush is the number of the last batch that was closed to
  32  *    new additions.
  33  * When we discover that we will need to write to any block in a stripe
  34  * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
  35  * the number of the batch it will be in. This is seq_flush+1.
  36  * When we are ready to do a write, if that batch hasn't been written yet,
  37  *   we plug the array and queue the stripe for later.
  38  * When an unplug happens, we increment bm_flush, thus closing the current
  39  *   batch.
  40  * When we notice that bm_flush > bm_write, we write out all pending updates
  41  * to the bitmap, and advance bm_write to where bm_flush was.
  42  * This may occasionally write a bit out twice, but is sure never to
  43  * miss any bits.
  44  */
  45
  46 #include <linux/blkdev.h>
  47 #include <linux/kthread.h>
  48 #include <linux/raid/pq.h>
  49 #include <linux/async_tx.h>
  50 #include <linux/module.h>
  51 #include <linux/async.h>
  52 #include <linux/seq_file.h>
  53 #include <linux/cpu.h>
  54 #include <linux/slab.h>
  55 #include <linux/ratelimit.h>
  56 #include <linux/nodemask.h>
  57
  58 #include <trace/events/block.h>
  59 #include <linux/list_sort.h>
  60
  61 #include "md.h"
  62 #include "raid5.h"
  63 #include "raid0.h"
  64 #include "md-bitmap.h"
  65 #include "raid5-log.h"
  66
  67 #define UNSUPPORTED_MDDEV_FLAGS (1L << MD_FAILFAST_SUPPORTED)
  68
  69 #define cpu_to_group(cpu) cpu_to_node(cpu)
  70 #define ANY_GROUP NUMA_NO_NODE
  71
  72 static bool devices_handle_discard_safely = false;
  73 module_param(devices_handle_discard_safely, bool, 0644);
  74 MODULE_PARM_DESC(devices_handle_discard_safely,
  75                  "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
  76 static struct workqueue_struct *raid5_wq;
  77
  78 static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
  79 {
  80         int hash = (sect >> STRIPE_SHIFT) & HASH_MASK;
  81         return &conf->stripe_hashtbl[hash];
  82 }
  83
  84 static inline int stripe_hash_locks_hash(sector_t sect)
  85 {
  86         return (sect >> STRIPE_SHIFT) & STRIPE_HASH_LOCKS_MASK;
  87 }
  88
  89 static inline void lock_device_hash_lock(struct r5conf *conf, int hash)
  90 {
  91         spin_lock_irq(conf->hash_locks + hash);
  92         spin_lock(&conf->device_lock);
  93 }
  94
  95 static inline void unlock_device_hash_lock(struct r5conf *conf, int hash)
  96 {
  97         spin_unlock(&conf->device_lock);
  98         spin_unlock_irq(conf->hash_locks + hash);
  99 }
 100
 101 static inline void lock_all_device_hash_locks_irq(struct r5conf *conf)
 102 {
 103         int i;
 104         spin_lock_irq(conf->hash_locks);
 105         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
 106                 spin_lock_nest_lock(conf->hash_locks + i, conf->hash_locks);
 107         spin_lock(&conf->device_lock);
 108 }
 109
 110 static inline void unlock_all_device_hash_locks_irq(struct r5conf *conf)
 111 {
 112         int i;
 113         spin_unlock(&conf->device_lock);
 114         for (i = NR_STRIPE_HASH_LOCKS - 1; i; i--)
 115                 spin_unlock(conf->hash_locks + i);
 116         spin_unlock_irq(conf->hash_locks);
 117 }
 118
 119 /* Find first data disk in a raid6 stripe */
 120 static inline int raid6_d0(struct stripe_head *sh)
 121 {
 122         if (sh->ddf_layout)
 123                 /* ddf always start from first device */
 124                 return 0;
 125         /* md starts just after Q block */
 126         if (sh->qd_idx == sh->disks - 1)
 127                 return 0;
 128         else
 129                 return sh->qd_idx + 1;
 130 }
 131 static inline int raid6_next_disk(int disk, int raid_disks)
 132 {
 133         disk++;
 134         return (disk < raid_disks) ? disk : 0;
 135 }
 136
 137 /* When walking through the disks in a raid5, starting at raid6_d0,
 138  * We need to map each disk to a 'slot', where the data disks are slot
 139  * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
 140  * is raid_disks-1.  This help does that mapping.
 141  */
 142 static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
 143                              int *count, int syndrome_disks)
 144 {
 145         int slot = *count;
 146
 147         if (sh->ddf_layout)
 148                 (*count)++;
 149         if (idx == sh->pd_idx)
 150                 return syndrome_disks;
 151         if (idx == sh->qd_idx)
 152                 return syndrome_disks + 1;
 153         if (!sh->ddf_layout)
 154                 (*count)++;
 155         return slot;
 156 }
 157
 158 static void print_raid5_conf (struct r5conf *conf);
 159
 160 static int stripe_operations_active(struct stripe_head *sh)
 161 {
 162         return sh->check_state || sh->reconstruct_state ||
 163                test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
 164                test_bit(STRIPE_COMPUTE_RUN, &sh->state);
 165 }
 166
 167 static bool stripe_is_lowprio(struct stripe_head *sh)
 168 {
 169         return (test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) ||
 170                 test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) &&
 171                !test_bit(STRIPE_R5C_CACHING, &sh->state);
 172 }
 173
 174 static void raid5_wakeup_stripe_thread(struct stripe_head *sh)
 175 {
 176         struct r5conf *conf = sh->raid_conf;
 177         struct r5worker_group *group;
 178         int thread_cnt;
 179         int i, cpu = sh->cpu;
 180
 181         if (!cpu_online(cpu)) {
 182                 cpu = cpumask_any(cpu_online_mask);
 183                 sh->cpu = cpu;
 184         }
 185
 186         if (list_empty(&sh->lru)) {
 187                 struct r5worker_group *group;
 188                 group = conf->worker_groups + cpu_to_group(cpu);
 189                 if (stripe_is_lowprio(sh))
 190                         list_add_tail(&sh->lru, &group->loprio_list);
 191                 else
 192                         list_add_tail(&sh->lru, &group->handle_list);
 193                 group->stripes_cnt++;
 194                 sh->group = group;
 195         }
 196
 197         if (conf->worker_cnt_per_group == 0) {
 198                 md_wakeup_thread(conf->mddev->thread);
 199                 return;
 200         }
 201
 202         group = conf->worker_groups + cpu_to_group(sh->cpu);
 203
 204         group->workers[0].working = true;
 205         /* at least one worker should run to avoid race */
 206         queue_work_on(sh->cpu, raid5_wq, &group->workers[0].work);
 207
 208         thread_cnt = group->stripes_cnt / MAX_STRIPE_BATCH - 1;
 209         /* wakeup more workers */
 210         for (i = 1; i < conf->worker_cnt_per_group && thread_cnt > 0; i++) {
 211                 if (group->workers[i].working == false) {
 212                         group->workers[i].working = true;
 213                         queue_work_on(sh->cpu, raid5_wq,
 214                                       &group->workers[i].work);
 215                         thread_cnt--;
 216                 }
 217         }
 218 }
 219
 220 static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh,
 221                               struct list_head *temp_inactive_list)
 222 {
 223         int i;
 224         int injournal = 0;      /* number of date pages with R5_InJournal */
 225
 226         BUG_ON(!list_empty(&sh->lru));
 227         BUG_ON(atomic_read(&conf->active_stripes)==0);
 228
 229         if (r5c_is_writeback(conf->log))
 230                 for (i = sh->disks; i--; )
 231                         if (test_bit(R5_InJournal, &sh->dev[i].flags))
 232                                 injournal++;
 233         /*
 234          * In the following cases, the stripe cannot be released to cached
 235          * lists. Therefore, we make the stripe write out and set
 236          * STRIPE_HANDLE:
 237          *   1. when quiesce in r5c write back;
 238          *   2. when resync is requested fot the stripe.
 239          */
 240         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) ||
 241             (conf->quiesce && r5c_is_writeback(conf->log) &&
 242              !test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0)) {
 243                 if (test_bit(STRIPE_R5C_CACHING, &sh->state))
 244                         r5c_make_stripe_write_out(sh);
 245                 set_bit(STRIPE_HANDLE, &sh->state);
 246         }
 247
 248         if (test_bit(STRIPE_HANDLE, &sh->state)) {
 249                 if (test_bit(STRIPE_DELAYED, &sh->state) &&
 250                     !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 251                         list_add_tail(&sh->lru, &conf->delayed_list);
 252                 else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
 253                            sh->bm_seq - conf->seq_write > 0)
 254                         list_add_tail(&sh->lru, &conf->bitmap_list);
 255                 else {
 256                         clear_bit(STRIPE_DELAYED, &sh->state);
 257                         clear_bit(STRIPE_BIT_DELAY, &sh->state);
 258                         if (conf->worker_cnt_per_group == 0) {
 259                                 if (stripe_is_lowprio(sh))
 260                                         list_add_tail(&sh->lru,
 261                                                         &conf->loprio_list);
 262                                 else
 263                                         list_add_tail(&sh->lru,
 264                                                         &conf->handle_list);
 265                         } else {
 266                                 raid5_wakeup_stripe_thread(sh);
 267                                 return;
 268                         }
 269                 }
 270                 md_wakeup_thread(conf->mddev->thread);
 271         } else {
 272                 BUG_ON(stripe_operations_active(sh));
 273                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 274                         if (atomic_dec_return(&conf->preread_active_stripes)
 275                             < IO_THRESHOLD)
 276                                 md_wakeup_thread(conf->mddev->thread);
 277                 atomic_dec(&conf->active_stripes);
 278                 if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
 279                         if (!r5c_is_writeback(conf->log))
 280                                 list_add_tail(&sh->lru, temp_inactive_list);
 281                         else {
 282                                 WARN_ON(test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags));
 283                                 if (injournal == 0)
 284                                         list_add_tail(&sh->lru, temp_inactive_list);
 285                                 else if (injournal == conf->raid_disks - conf->max_degraded) {
 286                                         /* full stripe */
 287                                         if (!test_and_set_bit(STRIPE_R5C_FULL_STRIPE, &sh->state))
 288                                                 atomic_inc(&conf->r5c_cached_full_stripes);
 289                                         if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
 290                                                 atomic_dec(&conf->r5c_cached_partial_stripes);
 291                                         list_add_tail(&sh->lru, &conf->r5c_full_stripe_list);
 292                                         r5c_check_cached_full_stripe(conf);
 293                                 } else
 294                                         /*
 295                                          * STRIPE_R5C_PARTIAL_STRIPE is set in
 296                                          * r5c_try_caching_write(). No need to
 297                                          * set it again.
 298                                          */
 299                                         list_add_tail(&sh->lru, &conf->r5c_partial_stripe_list);
 300                         }
 301                 }
 302         }
 303 }
 304
 305 static void __release_stripe(struct r5conf *conf, struct stripe_head *sh,
 306                              struct list_head *temp_inactive_list)
 307 {
 308         if (atomic_dec_and_test(&sh->count))
 309                 do_release_stripe(conf, sh, temp_inactive_list);
 310 }
 311
 312 /*
 313  * @hash could be NR_STRIPE_HASH_LOCKS, then we have a list of inactive_list
 314  *
 315  * Be careful: Only one task can add/delete stripes from temp_inactive_list at
 316  * given time. Adding stripes only takes device lock, while deleting stripes
 317  * only takes hash lock.
 318  */
 319 static void release_inactive_stripe_list(struct r5conf *conf,
 320                                          struct list_head *temp_inactive_list,
 321                                          int hash)
 322 {
 323         int size;
 324         bool do_wakeup = false;
 325         unsigned long flags;
 326
 327         if (hash == NR_STRIPE_HASH_LOCKS) {
 328                 size = NR_STRIPE_HASH_LOCKS;
 329                 hash = NR_STRIPE_HASH_LOCKS - 1;
 330         } else
 331                 size = 1;
 332         while (size) {
 333                 struct list_head *list = &temp_inactive_list[size - 1];
 334
 335                 /*
 336                  * We don't hold any lock here yet, raid5_get_active_stripe() might
 337                  * remove stripes from the list
 338                  */
 339                 if (!list_empty_careful(list)) {
 340                         spin_lock_irqsave(conf->hash_locks + hash, flags);
 341                         if (list_empty(conf->inactive_list + hash) &&
 342                             !list_empty(list))
 343                                 atomic_dec(&conf->empty_inactive_list_nr);
 344                         list_splice_tail_init(list, conf->inactive_list + hash);
 345                         do_wakeup = true;
 346                         spin_unlock_irqrestore(conf->hash_locks + hash, flags);
 347                 }
 348                 size--;
 349                 hash--;
 350         }
 351
 352         if (do_wakeup) {
 353                 wake_up(&conf->wait_for_stripe);
 354                 if (atomic_read(&conf->active_stripes) == 0)
 355                         wake_up(&conf->wait_for_quiescent);
 356                 if (conf->retry_read_aligned)
 357                         md_wakeup_thread(conf->mddev->thread);
 358         }
 359 }
 360
 361 /* should hold conf->device_lock already */
 362 static int release_stripe_list(struct r5conf *conf,
 363                                struct list_head *temp_inactive_list)
 364 {
 365         struct stripe_head *sh, *t;
 366         int count = 0;
 367         struct llist_node *head;
 368
 369         head = llist_del_all(&conf->released_stripes);
 370         head = llist_reverse_order(head);
 371         llist_for_each_entry_safe(sh, t, head, release_list) {
 372                 int hash;
 373
 374                 /* sh could be readded after STRIPE_ON_RELEASE_LIST is cleard */
 375                 smp_mb();
 376                 clear_bit(STRIPE_ON_RELEASE_LIST, &sh->state);
 377                 /*
 378                  * Don't worry the bit is set here, because if the bit is set
 379                  * again, the count is always > 1. This is true for
 380                  * STRIPE_ON_UNPLUG_LIST bit too.
 381                  */
 382                 hash = sh->hash_lock_index;
 383                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
 384                 count++;
 385         }
 386
 387         return count;
 388 }
 389
 390 void raid5_release_stripe(struct stripe_head *sh)
 391 {
 392         struct r5conf *conf = sh->raid_conf;
 393         unsigned long flags;
 394         struct list_head list;
 395         int hash;
 396         bool wakeup;
 397
 398         /* Avoid release_list until the last reference.
 399          */
 400         if (atomic_add_unless(&sh->count, -1, 1))
 401                 return;
 402
 403         if (unlikely(!conf->mddev->thread) ||
 404                 test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state))
 405                 goto slow_path;
 406         wakeup = llist_add(&sh->release_list, &conf->released_stripes);
 407         if (wakeup)
 408                 md_wakeup_thread(conf->mddev->thread);
 409         return;
 410 slow_path:
 411         /* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */
 412         if (atomic_dec_and_lock_irqsave(&sh->count, &conf->device_lock, flags)) {
 413                 INIT_LIST_HEAD(&list);
 414                 hash = sh->hash_lock_index;
 415                 do_release_stripe(conf, sh, &list);
 416                 spin_unlock_irqrestore(&conf->device_lock, flags);
 417                 release_inactive_stripe_list(conf, &list, hash);
 418         }
 419 }
 420
 421 static inline void remove_hash(struct stripe_head *sh)
 422 {
 423         pr_debug("remove_hash(), stripe %llu\n",
 424                 (unsigned long long)sh->sector);
 425
 426         hlist_del_init(&sh->hash);
 427 }
 428
 429 static inline void insert_hash(struct r5conf *conf, struct stripe_head *sh)
 430 {
 431         struct hlist_head *hp = stripe_hash(conf, sh->sector);
 432
 433         pr_debug("insert_hash(), stripe %llu\n",
 434                 (unsigned long long)sh->sector);
 435
 436         hlist_add_head(&sh->hash, hp);
 437 }
 438
 439 /* find an idle stripe, make sure it is unhashed, and return it. */
 440 static struct stripe_head *get_free_stripe(struct r5conf *conf, int hash)
 441 {
 442         struct stripe_head *sh = NULL;
 443         struct list_head *first;
 444
 445         if (list_empty(conf->inactive_list + hash))
 446                 goto out;
 447         first = (conf->inactive_list + hash)->next;
 448         sh = list_entry(first, struct stripe_head, lru);
 449         list_del_init(first);
 450         remove_hash(sh);
 451         atomic_inc(&conf->active_stripes);
 452         BUG_ON(hash != sh->hash_lock_index);
 453         if (list_empty(conf->inactive_list + hash))
 454                 atomic_inc(&conf->empty_inactive_list_nr);
 455 out:
 456         return sh;
 457 }
 458
 459 static void shrink_buffers(struct stripe_head *sh)
 460 {
 461         struct page *p;
 462         int i;
 463         int num = sh->raid_conf->pool_size;
 464
 465         for (i = 0; i < num ; i++) {
 466                 WARN_ON(sh->dev[i].page != sh->dev[i].orig_page);
 467                 p = sh->dev[i].page;
 468                 if (!p)
 469                         continue;
 470                 sh->dev[i].page = NULL;
 471                 put_page(p);
 472         }
 473 }
 474
 475 static int grow_buffers(struct stripe_head *sh, gfp_t gfp)
 476 {
 477         int i;
 478         int num = sh->raid_conf->pool_size;
 479
 480         for (i = 0; i < num; i++) {
 481                 struct page *page;
 482
 483                 if (!(page = alloc_page(gfp))) {
 484                         return 1;
 485                 }
 486                 sh->dev[i].page = page;
 487                 sh->dev[i].orig_page = page;
 488         }
 489
 490         return 0;
 491 }
 492
 493 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
 494                             struct stripe_head *sh);
 495
 496 static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
 497 {
 498         struct r5conf *conf = sh->raid_conf;
 499         int i, seq;
 500
 501         BUG_ON(atomic_read(&sh->count) != 0);
 502         BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
 503         BUG_ON(stripe_operations_active(sh));
 504         BUG_ON(sh->batch_head);
 505
 506         pr_debug("init_stripe called, stripe %llu\n",
 507                 (unsigned long long)sector);
 508 retry:
 509         seq = read_seqcount_begin(&conf->gen_lock);
 510         sh->generation = conf->generation - previous;
 511         sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
 512         sh->sector = sector;
 513         stripe_set_idx(sector, conf, previous, sh);
 514         sh->state = 0;
 515
 516         for (i = sh->disks; i--; ) {
 517                 struct r5dev *dev = &sh->dev[i];
 518
 519                 if (dev->toread || dev->read || dev->towrite || dev->written ||
 520                     test_bit(R5_LOCKED, &dev->flags)) {
 521                         pr_err("sector=%llx i=%d %p %p %p %p %d\n",
 522                                (unsigned long long)sh->sector, i, dev->toread,
 523                                dev->read, dev->towrite, dev->written,
 524                                test_bit(R5_LOCKED, &dev->flags));
 525                         WARN_ON(1);
 526                 }
 527                 dev->flags = 0;
 528                 dev->sector = raid5_compute_blocknr(sh, i, previous);
 529         }
 530         if (read_seqcount_retry(&conf->gen_lock, seq))
 531                 goto retry;
 532         sh->overwrite_disks = 0;
 533         insert_hash(conf, sh);
 534         sh->cpu = smp_processor_id();
 535         set_bit(STRIPE_BATCH_READY, &sh->state);
 536 }
 537
 538 static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
 539                                          short generation)
 540 {
 541         struct stripe_head *sh;
 542
 543         pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
 544         hlist_for_each_entry(sh, stripe_hash(conf, sector), hash)
 545                 if (sh->sector == sector && sh->generation == generation)
 546                         return sh;
 547         pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
 548         return NULL;
 549 }
 550
 551 /*
 552  * Need to check if array has failed when deciding whether to:
 553  *  - start an array
 554  *  - remove non-faulty devices
 555  *  - add a spare
 556  *  - allow a reshape
 557  * This determination is simple when no reshape is happening.
 558  * However if there is a reshape, we need to carefully check
 559  * both the before and after sections.
 560  * This is because some failed devices may only affect one
 561  * of the two sections, and some non-in_sync devices may
 562  * be insync in the section most affected by failed devices.
 563  */
 564 int raid5_calc_degraded(struct r5conf *conf)
 565 {
 566         int degraded, degraded2;
 567         int i;
 568
 569         rcu_read_lock();
 570         degraded = 0;
 571         for (i = 0; i < conf->previous_raid_disks; i++) {
 572                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 573                 if (rdev && test_bit(Faulty, &rdev->flags))
 574                         rdev = rcu_dereference(conf->disks[i].replacement);
 575                 if (!rdev || test_bit(Faulty, &rdev->flags))
 576                         degraded++;
 577                 else if (test_bit(In_sync, &rdev->flags))
 578                         ;
 579                 else
 580                         /* not in-sync or faulty.
 581                          * If the reshape increases the number of devices,
 582                          * this is being recovered by the reshape, so
 583                          * this 'previous' section is not in_sync.
 584                          * If the number of devices is being reduced however,
 585                          * the device can only be part of the array if
 586                          * we are reverting a reshape, so this section will
 587                          * be in-sync.
 588                          */
 589                         if (conf->raid_disks >= conf->previous_raid_disks)
 590                                 degraded++;
 591         }
 592         rcu_read_unlock();
 593         if (conf->raid_disks == conf->previous_raid_disks)
 594                 return degraded;
 595         rcu_read_lock();
 596         degraded2 = 0;
 597         for (i = 0; i < conf->raid_disks; i++) {
 598                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 599                 if (rdev && test_bit(Faulty, &rdev->flags))
 600                         rdev = rcu_dereference(conf->disks[i].replacement);
 601                 if (!rdev || test_bit(Faulty, &rdev->flags))
 602                         degraded2++;
 603                 else if (test_bit(In_sync, &rdev->flags))
 604                         ;
 605                 else
 606                         /* not in-sync or faulty.
 607                          * If reshape increases the number of devices, this
 608                          * section has already been recovered, else it
 609                          * almost certainly hasn't.
 610                          */
 611                         if (conf->raid_disks <= conf->previous_raid_disks)
 612                                 degraded2++;
 613         }
 614         rcu_read_unlock();
 615         if (degraded2 > degraded)
 616                 return degraded2;
 617         return degraded;
 618 }
 619
 620 static int has_failed(struct r5conf *conf)
 621 {
 622         int degraded;
 623
 624         if (conf->mddev->reshape_position == MaxSector)
 625                 return conf->mddev->degraded > conf->max_degraded;
 626
 627         degraded = raid5_calc_degraded(conf);
 628         if (degraded > conf->max_degraded)
 629                 return 1;
 630         return 0;
 631 }
 632
 633 struct stripe_head *
 634 raid5_get_active_stripe(struct r5conf *conf, sector_t sector,
 635                         int previous, int noblock, int noquiesce)
 636 {
 637         struct stripe_head *sh;
 638         int hash = stripe_hash_locks_hash(sector);
 639         int inc_empty_inactive_list_flag;
 640
 641         pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
 642
 643         spin_lock_irq(conf->hash_locks + hash);
 644
 645         do {
 646                 wait_event_lock_irq(conf->wait_for_quiescent,
 647                                     conf->quiesce == 0 || noquiesce,
 648                                     *(conf->hash_locks + hash));
 649                 sh = __find_stripe(conf, sector, conf->generation - previous);
 650                 if (!sh) {
 651                         if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state)) {
 652                                 sh = get_free_stripe(conf, hash);
 653                                 if (!sh && !test_bit(R5_DID_ALLOC,
 654                                                      &conf->cache_state))
 655                                         set_bit(R5_ALLOC_MORE,
 656                                                 &conf->cache_state);
 657                         }
 658                         if (noblock && sh == NULL)
 659                                 break;
 660
 661                         r5c_check_stripe_cache_usage(conf);
 662                         if (!sh) {
 663                                 set_bit(R5_INACTIVE_BLOCKED,
 664                                         &conf->cache_state);
 665                                 r5l_wake_reclaim(conf->log, 0);
 666                                 wait_event_lock_irq(
 667                                         conf->wait_for_stripe,
 668                                         !list_empty(conf->inactive_list + hash) &&
 669                                         (atomic_read(&conf->active_stripes)
 670                                          < (conf->max_nr_stripes * 3 / 4)
 671                                          || !test_bit(R5_INACTIVE_BLOCKED,
 672                                                       &conf->cache_state)),
 673                                         *(conf->hash_locks + hash));
 674                                 clear_bit(R5_INACTIVE_BLOCKED,
 675                                           &conf->cache_state);
 676                         } else {
 677                                 init_stripe(sh, sector, previous);
 678                                 atomic_inc(&sh->count);
 679                         }
 680                 } else if (!atomic_inc_not_zero(&sh->count)) {
 681                         spin_lock(&conf->device_lock);
 682                         if (!atomic_read(&sh->count)) {
 683                                 if (!test_bit(STRIPE_HANDLE, &sh->state))
 684                                         atomic_inc(&conf->active_stripes);
 685                                 BUG_ON(list_empty(&sh->lru) &&
 686                                        !test_bit(STRIPE_EXPANDING, &sh->state));
 687                                 inc_empty_inactive_list_flag = 0;
 688                                 if (!list_empty(conf->inactive_list + hash))
 689                                         inc_empty_inactive_list_flag = 1;
 690                                 list_del_init(&sh->lru);
 691                                 if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 692                                         atomic_inc(&conf->empty_inactive_list_nr);
 693                                 if (sh->group) {
 694                                         sh->group->stripes_cnt--;
 695                                         sh->group = NULL;
 696                                 }
 697                         }
 698                         atomic_inc(&sh->count);
 699                         spin_unlock(&conf->device_lock);
 700                 }
 701         } while (sh == NULL);
 702
 703         spin_unlock_irq(conf->hash_locks + hash);
 704         return sh;
 705 }
 706
 707 static bool is_full_stripe_write(struct stripe_head *sh)
 708 {
 709         BUG_ON(sh->overwrite_disks > (sh->disks - sh->raid_conf->max_degraded));
 710         return sh->overwrite_disks == (sh->disks - sh->raid_conf->max_degraded);
 711 }
 712
 713 static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 714                 __acquires(&sh1->stripe_lock)
 715                 __acquires(&sh2->stripe_lock)
 716 {
 717         if (sh1 > sh2) {
 718                 spin_lock_irq(&sh2->stripe_lock);
 719                 spin_lock_nested(&sh1->stripe_lock, 1);
 720         } else {
 721                 spin_lock_irq(&sh1->stripe_lock);
 722                 spin_lock_nested(&sh2->stripe_lock, 1);
 723         }
 724 }
 725
 726 static void unlock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 727                 __releases(&sh1->stripe_lock)
 728                 __releases(&sh2->stripe_lock)
 729 {
 730         spin_unlock(&sh1->stripe_lock);
 731         spin_unlock_irq(&sh2->stripe_lock);
 732 }
 733
 734 /* Only freshly new full stripe normal write stripe can be added to a batch list */
 735 static bool stripe_can_batch(struct stripe_head *sh)
 736 {
 737         struct r5conf *conf = sh->raid_conf;
 738
 739         if (raid5_has_log(conf) || raid5_has_ppl(conf))
 740                 return false;
 741         return test_bit(STRIPE_BATCH_READY, &sh->state) &&
 742                 !test_bit(STRIPE_BITMAP_PENDING, &sh->state) &&
 743                 is_full_stripe_write(sh);
 744 }
 745
 746 /* we only do back search */
 747 static void stripe_add_to_batch_list(struct r5conf *conf, struct stripe_head *sh)
 748 {
 749         struct stripe_head *head;
 750         sector_t head_sector, tmp_sec;
 751         int hash;
 752         int dd_idx;
 753         int inc_empty_inactive_list_flag;
 754
 755         /* Don't cross chunks, so stripe pd_idx/qd_idx is the same */
 756         tmp_sec = sh->sector;
 757         if (!sector_div(tmp_sec, conf->chunk_sectors))
 758                 return;
 759         head_sector = sh->sector - STRIPE_SECTORS;
 760
 761         hash = stripe_hash_locks_hash(head_sector);
 762         spin_lock_irq(conf->hash_locks + hash);
 763         head = __find_stripe(conf, head_sector, conf->generation);
 764         if (head && !atomic_inc_not_zero(&head->count)) {
 765                 spin_lock(&conf->device_lock);
 766                 if (!atomic_read(&head->count)) {
 767                         if (!test_bit(STRIPE_HANDLE, &head->state))
 768                                 atomic_inc(&conf->active_stripes);
 769                         BUG_ON(list_empty(&head->lru) &&
 770                                !test_bit(STRIPE_EXPANDING, &head->state));
 771                         inc_empty_inactive_list_flag = 0;
 772                         if (!list_empty(conf->inactive_list + hash))
 773                                 inc_empty_inactive_list_flag = 1;
 774                         list_del_init(&head->lru);
 775                         if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 776                                 atomic_inc(&conf->empty_inactive_list_nr);
 777                         if (head->group) {
 778                                 head->group->stripes_cnt--;
 779                                 head->group = NULL;
 780                         }
 781                 }
 782                 atomic_inc(&head->count);
 783                 spin_unlock(&conf->device_lock);
 784         }
 785         spin_unlock_irq(conf->hash_locks + hash);
 786
 787         if (!head)
 788                 return;
 789         if (!stripe_can_batch(head))
 790                 goto out;
 791
 792         lock_two_stripes(head, sh);
 793         /* clear_batch_ready clear the flag */
 794         if (!stripe_can_batch(head) || !stripe_can_batch(sh))
 795                 goto unlock_out;
 796
 797         if (sh->batch_head)
 798                 goto unlock_out;
 799
 800         dd_idx = 0;
 801         while (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
 802                 dd_idx++;
 803         if (head->dev[dd_idx].towrite->bi_opf != sh->dev[dd_idx].towrite->bi_opf ||
 804             bio_op(head->dev[dd_idx].towrite) != bio_op(sh->dev[dd_idx].towrite))
 805                 goto unlock_out;
 806
 807         if (head->batch_head) {
 808                 spin_lock(&head->batch_head->batch_lock);
 809                 /* This batch list is already running */
 810                 if (!stripe_can_batch(head)) {
 811                         spin_unlock(&head->batch_head->batch_lock);
 812                         goto unlock_out;
 813                 }
 814                 /*
 815                  * We must assign batch_head of this stripe within the
 816                  * batch_lock, otherwise clear_batch_ready of batch head
 817                  * stripe could clear BATCH_READY bit of this stripe and
 818                  * this stripe->batch_head doesn't get assigned, which
 819                  * could confuse clear_batch_ready for this stripe
 820                  */
 821                 sh->batch_head = head->batch_head;
 822
 823                 /*
 824                  * at this point, head's BATCH_READY could be cleared, but we
 825                  * can still add the stripe to batch list
 826                  */
 827                 list_add(&sh->batch_list, &head->batch_list);
 828                 spin_unlock(&head->batch_head->batch_lock);
 829         } else {
 830                 head->batch_head = head;
 831                 sh->batch_head = head->batch_head;
 832                 spin_lock(&head->batch_lock);
 833                 list_add_tail(&sh->batch_list, &head->batch_list);
 834                 spin_unlock(&head->batch_lock);
 835         }
 836
 837         if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 838                 if (atomic_dec_return(&conf->preread_active_stripes)
 839                     < IO_THRESHOLD)
 840                         md_wakeup_thread(conf->mddev->thread);
 841
 842         if (test_and_clear_bit(STRIPE_BIT_DELAY, &sh->state)) {
 843                 int seq = sh->bm_seq;
 844                 if (test_bit(STRIPE_BIT_DELAY, &sh->batch_head->state) &&
 845                     sh->batch_head->bm_seq > seq)
 846                         seq = sh->batch_head->bm_seq;
 847                 set_bit(STRIPE_BIT_DELAY, &sh->batch_head->state);
 848                 sh->batch_head->bm_seq = seq;
 849         }
 850
 851         atomic_inc(&sh->count);
 852 unlock_out:
 853         unlock_two_stripes(head, sh);
 854 out:
 855         raid5_release_stripe(head);
 856 }
 857
 858 /* Determine if 'data_offset' or 'new_data_offset' should be used
 859  * in this stripe_head.
 860  */
 861 static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
 862 {
 863         sector_t progress = conf->reshape_progress;
 864         /* Need a memory barrier to make sure we see the value
 865          * of conf->generation, or ->data_offset that was set before
 866          * reshape_progress was updated.
 867          */
 868         smp_rmb();
 869         if (progress == MaxSector)
 870                 return 0;
 871         if (sh->generation == conf->generation - 1)
 872                 return 0;
 873         /* We are in a reshape, and this is a new-generation stripe,
 874          * so use new_data_offset.
 875          */
 876         return 1;
 877 }
 878
 879 static void dispatch_bio_list(struct bio_list *tmp)
 880 {
 881         struct bio *bio;
 882
 883         while ((bio = bio_list_pop(tmp)))
 884                 generic_make_request(bio);
 885 }
 886
 887 static int cmp_stripe(void *priv, struct list_head *a, struct list_head *b)
 888 {
 889         const struct r5pending_data *da = list_entry(a,
 890                                 struct r5pending_data, sibling);
 891         const struct r5pending_data *db = list_entry(b,
 892                                 struct r5pending_data, sibling);
 893         if (da->sector > db->sector)
 894                 return 1;
 895         if (da->sector < db->sector)
 896                 return -1;
 897         return 0;
 898 }
 899
 900 static void dispatch_defer_bios(struct r5conf *conf, int target,
 901                                 struct bio_list *list)
 902 {
 903         struct r5pending_data *data;
 904         struct list_head *first, *next = NULL;
 905         int cnt = 0;
 906
 907         if (conf->pending_data_cnt == 0)
 908                 return;
 909
 910         list_sort(NULL, &conf->pending_list, cmp_stripe);
 911
 912         first = conf->pending_list.next;
 913
 914         /* temporarily move the head */
 915         if (conf->next_pending_data)
 916                 list_move_tail(&conf->pending_list,
 917                                 &conf->next_pending_data->sibling);
 918
 919         while (!list_empty(&conf->pending_list)) {
 920                 data = list_first_entry(&conf->pending_list,
 921                         struct r5pending_data, sibling);
 922                 if (&data->sibling == first)
 923                         first = data->sibling.next;
 924                 next = data->sibling.next;
 925
 926                 bio_list_merge(list, &data->bios);
 927                 list_move(&data->sibling, &conf->free_list);
 928                 cnt++;
 929                 if (cnt >= target)
 930                         break;
 931         }
 932         conf->pending_data_cnt -= cnt;
 933         BUG_ON(conf->pending_data_cnt < 0 || cnt < target);
 934
 935         if (next != &conf->pending_list)
 936                 conf->next_pending_data = list_entry(next,
 937                                 struct r5pending_data, sibling);
 938         else
 939                 conf->next_pending_data = NULL;
 940         /* list isn't empty */
 941         if (first != &conf->pending_list)
 942                 list_move_tail(&conf->pending_list, first);
 943 }
 944
 945 static void flush_deferred_bios(struct r5conf *conf)
 946 {
 947         struct bio_list tmp = BIO_EMPTY_LIST;
 948
 949         if (conf->pending_data_cnt == 0)
 950                 return;
 951
 952         spin_lock(&conf->pending_bios_lock);
 953         dispatch_defer_bios(conf, conf->pending_data_cnt, &tmp);
 954         BUG_ON(conf->pending_data_cnt != 0);
 955         spin_unlock(&conf->pending_bios_lock);
 956
 957         dispatch_bio_list(&tmp);
 958 }
 959
 960 static void defer_issue_bios(struct r5conf *conf, sector_t sector,
 961                                 struct bio_list *bios)
 962 {
 963         struct bio_list tmp = BIO_EMPTY_LIST;
 964         struct r5pending_data *ent;
 965
 966         spin_lock(&conf->pending_bios_lock);
 967         ent = list_first_entry(&conf->free_list, struct r5pending_data,
 968                                                         sibling);
 969         list_move_tail(&ent->sibling, &conf->pending_list);
 970         ent->sector = sector;
 971         bio_list_init(&ent->bios);
 972         bio_list_merge(&ent->bios, bios);
 973         conf->pending_data_cnt++;
 974         if (conf->pending_data_cnt >= PENDING_IO_MAX)
 975                 dispatch_defer_bios(conf, PENDING_IO_ONE_FLUSH, &tmp);
 976
 977         spin_unlock(&conf->pending_bios_lock);
 978
 979         dispatch_bio_list(&tmp);
 980 }
 981
 982 static void
 983 raid5_end_read_request(struct bio *bi);
 984 static void
 985 raid5_end_write_request(struct bio *bi);
 986
 987 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 988 {
 989         struct r5conf *conf = sh->raid_conf;
 990         int i, disks = sh->disks;
 991         struct stripe_head *head_sh = sh;
 992         struct bio_list pending_bios = BIO_EMPTY_LIST;
 993         bool should_defer;
 994
 995         might_sleep();
 996
 997         if (log_stripe(sh, s) == 0)
 998                 return;
 999
1000         should_defer = conf->batch_bio_dispatch && conf->group_cnt;
1001
1002         for (i = disks; i--; ) {
1003                 int op, op_flags = 0;
1004                 int replace_only = 0;
1005                 struct bio *bi, *rbi;
1006                 struct md_rdev *rdev, *rrdev = NULL;
1007
1008                 sh = head_sh;
1009                 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
1010                         op = REQ_OP_WRITE;
1011                         if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
1012                                 op_flags = REQ_FUA;
1013                         if (test_bit(R5_Discard, &sh->dev[i].flags))
1014                                 op = REQ_OP_DISCARD;
1015                 } else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1016                         op = REQ_OP_READ;
1017                 else if (test_and_clear_bit(R5_WantReplace,
1018                                             &sh->dev[i].flags)) {
1019                         op = REQ_OP_WRITE;
1020                         replace_only = 1;
1021                 } else
1022                         continue;
1023                 if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
1024                         op_flags |= REQ_SYNC;
1025
1026 again:
1027                 bi = &sh->dev[i].req;
1028                 rbi = &sh->dev[i].rreq; /* For writing to replacement */
1029
1030                 rcu_read_lock();
1031                 rrdev = rcu_dereference(conf->disks[i].replacement);
1032                 smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
1033                 rdev = rcu_dereference(conf->disks[i].rdev);
1034                 if (!rdev) {
1035                         rdev = rrdev;
1036                         rrdev = NULL;
1037                 }
1038                 if (op_is_write(op)) {
1039                         if (replace_only)
1040                                 rdev = NULL;
1041                         if (rdev == rrdev)
1042                                 /* We raced and saw duplicates */
1043                                 rrdev = NULL;
1044                 } else {
1045                         if (test_bit(R5_ReadRepl, &head_sh->dev[i].flags) && rrdev)
1046                                 rdev = rrdev;
1047                         rrdev = NULL;
1048                 }
1049
1050                 if (rdev && test_bit(Faulty, &rdev->flags))
1051                         rdev = NULL;
1052                 if (rdev)
1053                         atomic_inc(&rdev->nr_pending);
1054                 if (rrdev && test_bit(Faulty, &rrdev->flags))
1055                         rrdev = NULL;
1056                 if (rrdev)
1057                         atomic_inc(&rrdev->nr_pending);
1058                 rcu_read_unlock();
1059
1060                 /* We have already checked bad blocks for reads.  Now
1061                  * need to check for writes.  We never accept write errors
1062                  * on the replacement, so we don't to check rrdev.
1063                  */
1064                 while (op_is_write(op) && rdev &&
1065                        test_bit(WriteErrorSeen, &rdev->flags)) {
1066                         sector_t first_bad;
1067                         int bad_sectors;
1068                         int bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
1069                                               &first_bad, &bad_sectors);
1070                         if (!bad)
1071                                 break;
1072
1073                         if (bad < 0) {
1074                                 set_bit(BlockedBadBlocks, &rdev->flags);
1075                                 if (!conf->mddev->external &&
1076                                     conf->mddev->sb_flags) {
1077                                         /* It is very unlikely, but we might
1078                                          * still need to write out the
1079                                          * bad block log - better give it
1080                                          * a chance*/
1081                                         md_check_recovery(conf->mddev);
1082                                 }
1083                                 /*
1084                                  * Because md_wait_for_blocked_rdev
1085                                  * will dec nr_pending, we must
1086                                  * increment it first.
1087                                  */
1088                                 atomic_inc(&rdev->nr_pending);
1089                                 md_wait_for_blocked_rdev(rdev, conf->mddev);
1090                         } else {
1091                                 /* Acknowledged bad block - skip the write */
1092                                 rdev_dec_pending(rdev, conf->mddev);
1093                                 rdev = NULL;
1094                         }
1095                 }
1096
1097                 if (rdev) {
1098                         if (s->syncing || s->expanding || s->expanded
1099                             || s->replacing)
1100                                 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
1101
1102                         set_bit(STRIPE_IO_STARTED, &sh->state);
1103
1104                         bio_set_dev(bi, rdev->bdev);
1105                         bio_set_op_attrs(bi, op, op_flags);
1106                         bi->bi_end_io = op_is_write(op)
1107                                 ? raid5_end_write_request
1108                                 : raid5_end_read_request;
1109                         bi->bi_private = sh;
1110
1111                         pr_debug("%s: for %llu schedule op %d on disc %d\n",
1112                                 __func__, (unsigned long long)sh->sector,
1113                                 bi->bi_opf, i);
1114                         atomic_inc(&sh->count);
1115                         if (sh != head_sh)
1116                                 atomic_inc(&head_sh->count);
1117                         if (use_new_offset(conf, sh))
1118                                 bi->bi_iter.bi_sector = (sh->sector
1119                                                  + rdev->new_data_offset);
1120                         else
1121                                 bi->bi_iter.bi_sector = (sh->sector
1122                                                  + rdev->data_offset);
1123                         if (test_bit(R5_ReadNoMerge, &head_sh->dev[i].flags))
1124                                 bi->bi_opf |= REQ_NOMERGE;
1125
1126                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1127                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1128
1129                         if (!op_is_write(op) &&
1130                             test_bit(R5_InJournal, &sh->dev[i].flags))
1131                                 /*
1132                                  * issuing read for a page in journal, this
1133                                  * must be preparing for prexor in rmw; read
1134                                  * the data into orig_page
1135                                  */
1136                                 sh->dev[i].vec.bv_page = sh->dev[i].orig_page;
1137                         else
1138                                 sh->dev[i].vec.bv_page = sh->dev[i].page;
1139                         bi->bi_vcnt = 1;
1140                         bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1141                         bi->bi_io_vec[0].bv_offset = 0;
1142                         bi->bi_iter.bi_size = STRIPE_SIZE;
1143                         bi->bi_write_hint = sh->dev[i].write_hint;
1144                         if (!rrdev)
1145                                 sh->dev[i].write_hint = RWF_WRITE_LIFE_NOT_SET;
1146                         /*
1147                          * If this is discard request, set bi_vcnt 0. We don't
1148                          * want to confuse SCSI because SCSI will replace payload
1149                          */
1150                         if (op == REQ_OP_DISCARD)
1151                                 bi->bi_vcnt = 0;
1152                         if (rrdev)
1153                                 set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
1154
1155                         if (conf->mddev->gendisk)
1156                                 trace_block_bio_remap(bi->bi_disk->queue,
1157                                                       bi, disk_devt(conf->mddev->gendisk),
1158                                                       sh->dev[i].sector);
1159                         if (should_defer && op_is_write(op))
1160                                 bio_list_add(&pending_bios, bi);
1161                         else
1162                                 generic_make_request(bi);
1163                 }
1164                 if (rrdev) {
1165                         if (s->syncing || s->expanding || s->expanded
1166                             || s->replacing)
1167                                 md_sync_acct(rrdev->bdev, STRIPE_SECTORS);
1168
1169                         set_bit(STRIPE_IO_STARTED, &sh->state);
1170
1171                         bio_set_dev(rbi, rrdev->bdev);
1172                         bio_set_op_attrs(rbi, op, op_flags);
1173                         BUG_ON(!op_is_write(op));
1174                         rbi->bi_end_io = raid5_end_write_request;
1175                         rbi->bi_private = sh;
1176
1177                         pr_debug("%s: for %llu schedule op %d on "
1178                                  "replacement disc %d\n",
1179                                 __func__, (unsigned long long)sh->sector,
1180                                 rbi->bi_opf, i);
1181                         atomic_inc(&sh->count);
1182                         if (sh != head_sh)
1183                                 atomic_inc(&head_sh->count);
1184                         if (use_new_offset(conf, sh))
1185                                 rbi->bi_iter.bi_sector = (sh->sector
1186                                                   + rrdev->new_data_offset);
1187                         else
1188                                 rbi->bi_iter.bi_sector = (sh->sector
1189                                                   + rrdev->data_offset);
1190                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1191                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1192                         sh->dev[i].rvec.bv_page = sh->dev[i].page;
1193                         rbi->bi_vcnt = 1;
1194                         rbi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1195                         rbi->bi_io_vec[0].bv_offset = 0;
1196                         rbi->bi_iter.bi_size = STRIPE_SIZE;
1197                         rbi->bi_write_hint = sh->dev[i].write_hint;
1198                         sh->dev[i].write_hint = RWF_WRITE_LIFE_NOT_SET;
1199                         /*
1200                          * If this is discard request, set bi_vcnt 0. We don't
1201                          * want to confuse SCSI because SCSI will replace payload
1202                          */
1203                         if (op == REQ_OP_DISCARD)
1204                                 rbi->bi_vcnt = 0;
1205                         if (conf->mddev->gendisk)
1206                                 trace_block_bio_remap(rbi->bi_disk->queue,
1207                                                       rbi, disk_devt(conf->mddev->gendisk),
1208                                                       sh->dev[i].sector);
1209                         if (should_defer && op_is_write(op))
1210                                 bio_list_add(&pending_bios, rbi);
1211                         else
1212                                 generic_make_request(rbi);
1213                 }
1214                 if (!rdev && !rrdev) {
1215                         if (op_is_write(op))
1216                                 set_bit(STRIPE_DEGRADED, &sh->state);
1217                         pr_debug("skip op %d on disc %d for sector %llu\n",
1218                                 bi->bi_opf, i, (unsigned long long)sh->sector);
1219                         clear_bit(R5_LOCKED, &sh->dev[i].flags);
1220                         set_bit(STRIPE_HANDLE, &sh->state);
1221                 }
1222
1223                 if (!head_sh->batch_head)
1224                         continue;
1225                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1226                                       batch_list);
1227                 if (sh != head_sh)
1228                         goto again;
1229         }
1230
1231         if (should_defer && !bio_list_empty(&pending_bios))
1232                 defer_issue_bios(conf, head_sh->sector, &pending_bios);
1233 }
1234
1235 static struct dma_async_tx_descriptor *
1236 async_copy_data(int frombio, struct bio *bio, struct page **page,
1237         sector_t sector, struct dma_async_tx_descriptor *tx,
1238         struct stripe_head *sh, int no_skipcopy)
1239 {
1240         struct bio_vec bvl;
1241         struct bvec_iter iter;
1242         struct page *bio_page;
1243         int page_offset;
1244         struct async_submit_ctl submit;
1245         enum async_tx_flags flags = 0;
1246
1247         if (bio->bi_iter.bi_sector >= sector)
1248                 page_offset = (signed)(bio->bi_iter.bi_sector - sector) * 512;
1249         else
1250                 page_offset = (signed)(sector - bio->bi_iter.bi_sector) * -512;
1251
1252         if (frombio)
1253                 flags |= ASYNC_TX_FENCE;
1254         init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
1255
1256         bio_for_each_segment(bvl, bio, iter) {
1257                 int len = bvl.bv_len;
1258                 int clen;
1259                 int b_offset = 0;
1260
1261                 if (page_offset < 0) {
1262                         b_offset = -page_offset;
1263                         page_offset += b_offset;
1264                         len -= b_offset;
1265                 }
1266
1267                 if (len > 0 && page_offset + len > STRIPE_SIZE)
1268                         clen = STRIPE_SIZE - page_offset;
1269                 else
1270                         clen = len;
1271
1272                 if (clen > 0) {
1273                         b_offset += bvl.bv_offset;
1274                         bio_page = bvl.bv_page;
1275                         if (frombio) {
1276                                 if (sh->raid_conf->skip_copy &&
1277                                     b_offset == 0 && page_offset == 0 &&
1278                                     clen == STRIPE_SIZE &&
1279                                     !no_skipcopy)
1280                                         *page = bio_page;
1281                                 else
1282                                         tx = async_memcpy(*page, bio_page, page_offset,
1283                                                   b_offset, clen, &submit);
1284                         } else
1285                                 tx = async_memcpy(bio_page, *page, b_offset,
1286                                                   page_offset, clen, &submit);
1287                 }
1288                 /* chain the operations */
1289                 submit.depend_tx = tx;
1290
1291                 if (clen < len) /* hit end of page */
1292                         break;
1293                 page_offset +=  len;
1294         }
1295
1296         return tx;
1297 }
1298
1299 static void ops_complete_biofill(void *stripe_head_ref)
1300 {
1301         struct stripe_head *sh = stripe_head_ref;
1302         int i;
1303
1304         pr_debug("%s: stripe %llu\n", __func__,
1305                 (unsigned long long)sh->sector);
1306
1307         /* clear completed biofills */
1308         for (i = sh->disks; i--; ) {
1309                 struct r5dev *dev = &sh->dev[i];
1310
1311                 /* acknowledge completion of a biofill operation */
1312                 /* and check if we need to reply to a read request,
1313                  * new R5_Wantfill requests are held off until
1314                  * !STRIPE_BIOFILL_RUN
1315                  */
1316                 if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
1317                         struct bio *rbi, *rbi2;
1318
1319                         BUG_ON(!dev->read);
1320                         rbi = dev->read;
1321                         dev->read = NULL;
1322                         while (rbi && rbi->bi_iter.bi_sector <
1323                                 dev->sector + STRIPE_SECTORS) {
1324                                 rbi2 = r5_next_bio(rbi, dev->sector);
1325                                 bio_endio(rbi);
1326                                 rbi = rbi2;
1327                         }
1328                 }
1329         }
1330         clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
1331
1332         set_bit(STRIPE_HANDLE, &sh->state);
1333         raid5_release_stripe(sh);
1334 }
1335
1336 static void ops_run_biofill(struct stripe_head *sh)
1337 {
1338         struct dma_async_tx_descriptor *tx = NULL;
1339         struct async_submit_ctl submit;
1340         int i;
1341
1342         BUG_ON(sh->batch_head);
1343         pr_debug("%s: stripe %llu\n", __func__,
1344                 (unsigned long long)sh->sector);
1345
1346         for (i = sh->disks; i--; ) {
1347                 struct r5dev *dev = &sh->dev[i];
1348                 if (test_bit(R5_Wantfill, &dev->flags)) {
1349                         struct bio *rbi;
1350                         spin_lock_irq(&sh->stripe_lock);
1351                         dev->read = rbi = dev->toread;
1352                         dev->toread = NULL;
1353                         spin_unlock_irq(&sh->stripe_lock);
1354                         while (rbi && rbi->bi_iter.bi_sector <
1355                                 dev->sector + STRIPE_SECTORS) {
1356                                 tx = async_copy_data(0, rbi, &dev->page,
1357                                                      dev->sector, tx, sh, 0);
1358                                 rbi = r5_next_bio(rbi, dev->sector);
1359                         }
1360                 }
1361         }
1362
1363         atomic_inc(&sh->count);
1364         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
1365         async_trigger_callback(&submit);
1366 }
1367
1368 static void mark_target_uptodate(struct stripe_head *sh, int target)
1369 {
1370         struct r5dev *tgt;
1371
1372         if (target < 0)
1373                 return;
1374
1375         tgt = &sh->dev[target];
1376         set_bit(R5_UPTODATE, &tgt->flags);
1377         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1378         clear_bit(R5_Wantcompute, &tgt->flags);
1379 }
1380
1381 static void ops_complete_compute(void *stripe_head_ref)
1382 {
1383         struct stripe_head *sh = stripe_head_ref;
1384
1385         pr_debug("%s: stripe %llu\n", __func__,
1386                 (unsigned long long)sh->sector);
1387
1388         /* mark the computed target(s) as uptodate */
1389         mark_target_uptodate(sh, sh->ops.target);
1390         mark_target_uptodate(sh, sh->ops.target2);
1391
1392         clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
1393         if (sh->check_state == check_state_compute_run)
1394                 sh->check_state = check_state_compute_result;
1395         set_bit(STRIPE_HANDLE, &sh->state);
1396         raid5_release_stripe(sh);
1397 }
1398
1399 /* return a pointer to the address conversion region of the scribble buffer */
1400 static struct page **to_addr_page(struct raid5_percpu *percpu, int i)
1401 {
1402         return percpu->scribble + i * percpu->scribble_obj_size;
1403 }
1404
1405 /* return a pointer to the address conversion region of the scribble buffer */
1406 static addr_conv_t *to_addr_conv(struct stripe_head *sh,
1407                                  struct raid5_percpu *percpu, int i)
1408 {
1409         return (void *) (to_addr_page(percpu, i) + sh->disks + 2);
1410 }
1411
1412 static struct dma_async_tx_descriptor *
1413 ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
1414 {
1415         int disks = sh->disks;
1416         struct page **xor_srcs = to_addr_page(percpu, 0);
1417         int target = sh->ops.target;
1418         struct r5dev *tgt = &sh->dev[target];
1419         struct page *xor_dest = tgt->page;
1420         int count = 0;
1421         struct dma_async_tx_descriptor *tx;
1422         struct async_submit_ctl submit;
1423         int i;
1424
1425         BUG_ON(sh->batch_head);
1426
1427         pr_debug("%s: stripe %llu block: %d\n",
1428                 __func__, (unsigned long long)sh->sector, target);
1429         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1430
1431         for (i = disks; i--; )
1432                 if (i != target)
1433                         xor_srcs[count++] = sh->dev[i].page;
1434
1435         atomic_inc(&sh->count);
1436
1437         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
1438                           ops_complete_compute, sh, to_addr_conv(sh, percpu, 0));
1439         if (unlikely(count == 1))
1440                 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
1441         else
1442                 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1443
1444         return tx;
1445 }
1446
1447 /* set_syndrome_sources - populate source buffers for gen_syndrome
1448  * @srcs - (struct page *) array of size sh->disks
1449  * @sh - stripe_head to parse
1450  *
1451  * Populates srcs in proper layout order for the stripe and returns the
1452  * 'count' of sources to be used in a call to async_gen_syndrome.  The P
1453  * destination buffer is recorded in srcs[count] and the Q destination
1454  * is recorded in srcs[count+1]].
1455  */
1456 static int set_syndrome_sources(struct page **srcs,
1457                                 struct stripe_head *sh,
1458                                 int srctype)
1459 {
1460         int disks = sh->disks;
1461         int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
1462         int d0_idx = raid6_d0(sh);
1463         int count;
1464         int i;
1465
1466         for (i = 0; i < disks; i++)
1467                 srcs[i] = NULL;
1468
1469         count = 0;
1470         i = d0_idx;
1471         do {
1472                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1473                 struct r5dev *dev = &sh->dev[i];
1474
1475                 if (i == sh->qd_idx || i == sh->pd_idx ||
1476                     (srctype == SYNDROME_SRC_ALL) ||
1477                     (srctype == SYNDROME_SRC_WANT_DRAIN &&
1478                      (test_bit(R5_Wantdrain, &dev->flags) ||
1479                       test_bit(R5_InJournal, &dev->flags))) ||
1480                     (srctype == SYNDROME_SRC_WRITTEN &&
1481                      (dev->written ||
1482                       test_bit(R5_InJournal, &dev->flags)))) {
1483                         if (test_bit(R5_InJournal, &dev->flags))
1484                                 srcs[slot] = sh->dev[i].orig_page;
1485                         else
1486                                 srcs[slot] = sh->dev[i].page;
1487                 }
1488                 i = raid6_next_disk(i, disks);
1489         } while (i != d0_idx);
1490
1491         return syndrome_disks;
1492 }
1493
1494 static struct dma_async_tx_descriptor *
1495 ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
1496 {
1497         int disks = sh->disks;
1498         struct page **blocks = to_addr_page(percpu, 0);
1499         int target;
1500         int qd_idx = sh->qd_idx;
1501         struct dma_async_tx_descriptor *tx;
1502         struct async_submit_ctl submit;
1503         struct r5dev *tgt;
1504         struct page *dest;
1505         int i;
1506         int count;
1507
1508         BUG_ON(sh->batch_head);
1509         if (sh->ops.target < 0)
1510                 target = sh->ops.target2;
1511         else if (sh->ops.target2 < 0)
1512                 target = sh->ops.target;
1513         else
1514                 /* we should only have one valid target */
1515                 BUG();
1516         BUG_ON(target < 0);
1517         pr_debug("%s: stripe %llu block: %d\n",
1518                 __func__, (unsigned long long)sh->sector, target);
1519
1520         tgt = &sh->dev[target];
1521         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1522         dest = tgt->page;
1523
1524         atomic_inc(&sh->count);
1525
1526         if (target == qd_idx) {
1527                 count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1528                 blocks[count] = NULL; /* regenerating p is not necessary */
1529                 BUG_ON(blocks[count+1] != dest); /* q should already be set */
1530                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1531                                   ops_complete_compute, sh,
1532                                   to_addr_conv(sh, percpu, 0));
1533                 tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
1534         } else {
1535                 /* Compute any data- or p-drive using XOR */
1536                 count = 0;
1537                 for (i = disks; i-- ; ) {
1538                         if (i == target || i == qd_idx)
1539                                 continue;
1540                         blocks[count++] = sh->dev[i].page;
1541                 }
1542
1543                 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1544                                   NULL, ops_complete_compute, sh,
1545                                   to_addr_conv(sh, percpu, 0));
1546                 tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
1547         }
1548
1549         return tx;
1550 }
1551
1552 static struct dma_async_tx_descriptor *
1553 ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
1554 {
1555         int i, count, disks = sh->disks;
1556         int syndrome_disks = sh->ddf_layout ? disks : disks-2;
1557         int d0_idx = raid6_d0(sh);
1558         int faila = -1, failb = -1;
1559         int target = sh->ops.target;
1560         int target2 = sh->ops.target2;
1561         struct r5dev *tgt = &sh->dev[target];
1562         struct r5dev *tgt2 = &sh->dev[target2];
1563         struct dma_async_tx_descriptor *tx;
1564         struct page **blocks = to_addr_page(percpu, 0);
1565         struct async_submit_ctl submit;
1566
1567         BUG_ON(sh->batch_head);
1568         pr_debug("%s: stripe %llu block1: %d block2: %d\n",
1569                  __func__, (unsigned long long)sh->sector, target, target2);
1570         BUG_ON(target < 0 || target2 < 0);
1571         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1572         BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
1573
1574         /* we need to open-code set_syndrome_sources to handle the
1575          * slot number conversion for 'faila' and 'failb'
1576          */
1577         for (i = 0; i < disks ; i++)
1578                 blocks[i] = NULL;
1579         count = 0;
1580         i = d0_idx;
1581         do {
1582                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1583
1584                 blocks[slot] = sh->dev[i].page;
1585
1586                 if (i == target)
1587                         faila = slot;
1588                 if (i == target2)
1589                         failb = slot;
1590                 i = raid6_next_disk(i, disks);
1591         } while (i != d0_idx);
1592
1593         BUG_ON(faila == failb);
1594         if (failb < faila)
1595                 swap(faila, failb);
1596         pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
1597                  __func__, (unsigned long long)sh->sector, faila, failb);
1598
1599         atomic_inc(&sh->count);
1600
1601         if (failb == syndrome_disks+1) {
1602                 /* Q disk is one of the missing disks */
1603                 if (faila == syndrome_disks) {
1604                         /* Missing P+Q, just recompute */
1605                         init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1606                                           ops_complete_compute, sh,
1607                                           to_addr_conv(sh, percpu, 0));
1608                         return async_gen_syndrome(blocks, 0, syndrome_disks+2,
1609                                                   STRIPE_SIZE, &submit);
1610                 } else {
1611                         struct page *dest;
1612                         int data_target;
1613                         int qd_idx = sh->qd_idx;
1614
1615                         /* Missing D+Q: recompute D from P, then recompute Q */
1616                         if (target == qd_idx)
1617                                 data_target = target2;
1618                         else
1619                                 data_target = target;
1620
1621                         count = 0;
1622                         for (i = disks; i-- ; ) {
1623                                 if (i == data_target || i == qd_idx)
1624                                         continue;
1625                                 blocks[count++] = sh->dev[i].page;
1626                         }
1627                         dest = sh->dev[data_target].page;
1628                         init_async_submit(&submit,
1629                                           ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1630                                           NULL, NULL, NULL,
1631                                           to_addr_conv(sh, percpu, 0));
1632                         tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
1633                                        &submit);
1634
1635                         count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1636                         init_async_submit(&submit, ASYNC_TX_FENCE, tx,
1637                                           ops_complete_compute, sh,
1638                                           to_addr_conv(sh, percpu, 0));
1639                         return async_gen_syndrome(blocks, 0, count+2,
1640                                                   STRIPE_SIZE, &submit);
1641                 }
1642         } else {
1643                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1644                                   ops_complete_compute, sh,
1645                                   to_addr_conv(sh, percpu, 0));
1646                 if (failb == syndrome_disks) {
1647                         /* We're missing D+P. */
1648                         return async_raid6_datap_recov(syndrome_disks+2,
1649                                                        STRIPE_SIZE, faila,
1650                                                        blocks, &submit);
1651                 } else {
1652                         /* We're missing D+D. */
1653                         return async_raid6_2data_recov(syndrome_disks+2,
1654                                                        STRIPE_SIZE, faila, failb,
1655                                                        blocks, &submit);
1656                 }
1657         }
1658 }
1659
1660 static void ops_complete_prexor(void *stripe_head_ref)
1661 {
1662         struct stripe_head *sh = stripe_head_ref;
1663
1664         pr_debug("%s: stripe %llu\n", __func__,
1665                 (unsigned long long)sh->sector);
1666
1667         if (r5c_is_writeback(sh->raid_conf->log))
1668                 /*
1669                  * raid5-cache write back uses orig_page during prexor.
1670                  * After prexor, it is time to free orig_page
1671                  */
1672                 r5c_release_extra_page(sh);
1673 }
1674
1675 static struct dma_async_tx_descriptor *
1676 ops_run_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
1677                 struct dma_async_tx_descriptor *tx)
1678 {
1679         int disks = sh->disks;
1680         struct page **xor_srcs = to_addr_page(percpu, 0);
1681         int count = 0, pd_idx = sh->pd_idx, i;
1682         struct async_submit_ctl submit;
1683
1684         /* existing parity data subtracted */
1685         struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1686
1687         BUG_ON(sh->batch_head);
1688         pr_debug("%s: stripe %llu\n", __func__,
1689                 (unsigned long long)sh->sector);
1690
1691         for (i = disks; i--; ) {
1692                 struct r5dev *dev = &sh->dev[i];
1693                 /* Only process blocks that are known to be uptodate */
1694                 if (test_bit(R5_InJournal, &dev->flags))
1695                         xor_srcs[count++] = dev->orig_page;
1696                 else if (test_bit(R5_Wantdrain, &dev->flags))
1697                         xor_srcs[count++] = dev->page;
1698         }
1699
1700         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1701                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1702         tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1703
1704         return tx;
1705 }
1706
1707 static struct dma_async_tx_descriptor *
1708 ops_run_prexor6(struct stripe_head *sh, struct raid5_percpu *percpu,
1709                 struct dma_async_tx_descriptor *tx)
1710 {
1711         struct page **blocks = to_addr_page(percpu, 0);
1712         int count;
1713         struct async_submit_ctl submit;
1714
1715         pr_debug("%s: stripe %llu\n", __func__,
1716                 (unsigned long long)sh->sector);
1717
1718         count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_WANT_DRAIN);
1719
1720         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_PQ_XOR_DST, tx,
1721                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1722         tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
1723
1724         return tx;
1725 }
1726
1727 static struct dma_async_tx_descriptor *
1728 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1729 {
1730         struct r5conf *conf = sh->raid_conf;
1731         int disks = sh->disks;
1732         int i;
1733         struct stripe_head *head_sh = sh;
1734
1735         pr_debug("%s: stripe %llu\n", __func__,
1736                 (unsigned long long)sh->sector);
1737
1738         for (i = disks; i--; ) {
1739                 struct r5dev *dev;
1740                 struct bio *chosen;
1741
1742                 sh = head_sh;
1743                 if (test_and_clear_bit(R5_Wantdrain, &head_sh->dev[i].flags)) {
1744                         struct bio *wbi;
1745
1746 again:
1747                         dev = &sh->dev[i];
1748                         /*
1749                          * clear R5_InJournal, so when rewriting a page in
1750                          * journal, it is not skipped by r5l_log_stripe()
1751                          */
1752                         clear_bit(R5_InJournal, &dev->flags);
1753                         spin_lock_irq(&sh->stripe_lock);
1754                         chosen = dev->towrite;
1755                         dev->towrite = NULL;
1756                         sh->overwrite_disks = 0;
1757                         BUG_ON(dev->written);
1758                         wbi = dev->written = chosen;
1759                         spin_unlock_irq(&sh->stripe_lock);
1760                         WARN_ON(dev->page != dev->orig_page);
1761
1762                         while (wbi && wbi->bi_iter.bi_sector <
1763                                 dev->sector + STRIPE_SECTORS) {
1764                                 if (wbi->bi_opf & REQ_FUA)
1765                                         set_bit(R5_WantFUA, &dev->flags);
1766                                 if (wbi->bi_opf & REQ_SYNC)
1767                                         set_bit(R5_SyncIO, &dev->flags);
1768                                 if (bio_op(wbi) == REQ_OP_DISCARD)
1769                                         set_bit(R5_Discard, &dev->flags);
1770                                 else {
1771                                         tx = async_copy_data(1, wbi, &dev->page,
1772                                                              dev->sector, tx, sh,
1773                                                              r5c_is_writeback(conf->log));
1774                                         if (dev->page != dev->orig_page &&
1775                                             !r5c_is_writeback(conf->log)) {
1776                                                 set_bit(R5_SkipCopy, &dev->flags);
1777                                                 clear_bit(R5_UPTODATE, &dev->flags);
1778                                                 clear_bit(R5_OVERWRITE, &dev->flags);
1779                                         }
1780                                 }
1781                                 wbi = r5_next_bio(wbi, dev->sector);
1782                         }
1783
1784                         if (head_sh->batch_head) {
1785                                 sh = list_first_entry(&sh->batch_list,
1786                                                       struct stripe_head,
1787                                                       batch_list);
1788                                 if (sh == head_sh)
1789                                         continue;
1790                                 goto again;
1791                         }
1792                 }
1793         }
1794
1795         return tx;
1796 }
1797
1798 static void ops_complete_reconstruct(void *stripe_head_ref)
1799 {
1800         struct stripe_head *sh = stripe_head_ref;
1801         int disks = sh->disks;
1802         int pd_idx = sh->pd_idx;
1803         int qd_idx = sh->qd_idx;
1804         int i;
1805         bool fua = false, sync = false, discard = false;
1806
1807         pr_debug("%s: stripe %llu\n", __func__,
1808                 (unsigned long long)sh->sector);
1809
1810         for (i = disks; i--; ) {
1811                 fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
1812                 sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
1813                 discard |= test_bit(R5_Discard, &sh->dev[i].flags);
1814         }
1815
1816         for (i = disks; i--; ) {
1817                 struct r5dev *dev = &sh->dev[i];
1818
1819                 if (dev->written || i == pd_idx || i == qd_idx) {
1820                         if (!discard && !test_bit(R5_SkipCopy, &dev->flags)) {
1821                                 set_bit(R5_UPTODATE, &dev->flags);
1822                                 if (test_bit(STRIPE_EXPAND_READY, &sh->state))
1823                                         set_bit(R5_Expanded, &dev->flags);
1824                         }
1825                         if (fua)
1826                                 set_bit(R5_WantFUA, &dev->flags);
1827                         if (sync)
1828                                 set_bit(R5_SyncIO, &dev->flags);
1829                 }
1830         }
1831
1832         if (sh->reconstruct_state == reconstruct_state_drain_run)
1833                 sh->reconstruct_state = reconstruct_state_drain_result;
1834         else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
1835                 sh->reconstruct_state = reconstruct_state_prexor_drain_result;
1836         else {
1837                 BUG_ON(sh->reconstruct_state != reconstruct_state_run);
1838                 sh->reconstruct_state = reconstruct_state_result;
1839         }
1840
1841         set_bit(STRIPE_HANDLE, &sh->state);
1842         raid5_release_stripe(sh);
1843 }
1844
1845 static void
1846 ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
1847                      struct dma_async_tx_descriptor *tx)
1848 {
1849         int disks = sh->disks;
1850         struct page **xor_srcs;
1851         struct async_submit_ctl submit;
1852         int count, pd_idx = sh->pd_idx, i;
1853         struct page *xor_dest;
1854         int prexor = 0;
1855         unsigned long flags;
1856         int j = 0;
1857         struct stripe_head *head_sh = sh;
1858         int last_stripe;
1859
1860         pr_debug("%s: stripe %llu\n", __func__,
1861                 (unsigned long long)sh->sector);
1862
1863         for (i = 0; i < sh->disks; i++) {
1864                 if (pd_idx == i)
1865                         continue;
1866                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
1867                         break;
1868         }
1869         if (i >= sh->disks) {
1870                 atomic_inc(&sh->count);
1871                 set_bit(R5_Discard, &sh->dev[pd_idx].flags);
1872                 ops_complete_reconstruct(sh);
1873                 return;
1874         }
1875 again:
1876         count = 0;
1877         xor_srcs = to_addr_page(percpu, j);
1878         /* check if prexor is active which means only process blocks
1879          * that are part of a read-modify-write (written)
1880          */
1881         if (head_sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1882                 prexor = 1;
1883                 xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1884                 for (i = disks; i--; ) {
1885                         struct r5dev *dev = &sh->dev[i];
1886                         if (head_sh->dev[i].written ||
1887                             test_bit(R5_InJournal, &head_sh->dev[i].flags))
1888                                 xor_srcs[count++] = dev->page;
1889                 }
1890         } else {
1891                 xor_dest = sh->dev[pd_idx].page;
1892                 for (i = disks; i--; ) {
1893                         struct r5dev *dev = &sh->dev[i];
1894                         if (i != pd_idx)
1895                                 xor_srcs[count++] = dev->page;
1896                 }
1897         }
1898
1899         /* 1/ if we prexor'd then the dest is reused as a source
1900          * 2/ if we did not prexor then we are redoing the parity
1901          * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
1902          * for the synchronous xor case
1903          */
1904         last_stripe = !head_sh->batch_head ||
1905                 list_first_entry(&sh->batch_list,
1906                                  struct stripe_head, batch_list) == head_sh;
1907         if (last_stripe) {
1908                 flags = ASYNC_TX_ACK |
1909                         (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
1910
1911                 atomic_inc(&head_sh->count);
1912                 init_async_submit(&submit, flags, tx, ops_complete_reconstruct, head_sh,
1913                                   to_addr_conv(sh, percpu, j));
1914         } else {
1915                 flags = prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST;
1916                 init_async_submit(&submit, flags, tx, NULL, NULL,
1917                                   to_addr_conv(sh, percpu, j));
1918         }
1919
1920         if (unlikely(count == 1))
1921                 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
1922         else
1923                 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1924         if (!last_stripe) {
1925                 j++;
1926                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1927                                       batch_list);
1928                 goto again;
1929         }
1930 }
1931
1932 static void
1933 ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
1934                      struct dma_async_tx_descriptor *tx)
1935 {
1936         struct async_submit_ctl submit;
1937         struct page **blocks;
1938         int count, i, j = 0;
1939         struct stripe_head *head_sh = sh;
1940         int last_stripe;
1941         int synflags;
1942         unsigned long txflags;
1943
1944         pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
1945
1946         for (i = 0; i < sh->disks; i++) {
1947                 if (sh->pd_idx == i || sh->qd_idx == i)
1948                         continue;
1949                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
1950                         break;
1951         }
1952         if (i >= sh->disks) {
1953                 atomic_inc(&sh->count);
1954                 set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
1955                 set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
1956                 ops_complete_reconstruct(sh);
1957                 return;
1958         }
1959
1960 again:
1961         blocks = to_addr_page(percpu, j);
1962
1963         if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1964                 synflags = SYNDROME_SRC_WRITTEN;
1965                 txflags = ASYNC_TX_ACK | ASYNC_TX_PQ_XOR_DST;
1966         } else {
1967                 synflags = SYNDROME_SRC_ALL;
1968                 txflags = ASYNC_TX_ACK;
1969         }
1970
1971         count = set_syndrome_sources(blocks, sh, synflags);
1972         last_stripe = !head_sh->batch_head ||
1973                 list_first_entry(&sh->batch_list,
1974                                  struct stripe_head, batch_list) == head_sh;
1975
1976         if (last_stripe) {
1977                 atomic_inc(&head_sh->count);
1978                 init_async_submit(&submit, txflags, tx, ops_complete_reconstruct,
1979                                   head_sh, to_addr_conv(sh, percpu, j));
1980         } else
1981                 init_async_submit(&submit, 0, tx, NULL, NULL,
1982                                   to_addr_conv(sh, percpu, j));
1983         tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
1984         if (!last_stripe) {
1985                 j++;
1986                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1987                                       batch_list);
1988                 goto again;
1989         }
1990 }
1991
1992 static void ops_complete_check(void *stripe_head_ref)
1993 {
1994         struct stripe_head *sh = stripe_head_ref;
1995
1996         pr_debug("%s: stripe %llu\n", __func__,
1997                 (unsigned long long)sh->sector);
1998
1999         sh->check_state = check_state_check_result;
2000         set_bit(STRIPE_HANDLE, &sh->state);
2001         raid5_release_stripe(sh);
2002 }
2003
2004 static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
2005 {
2006         int disks = sh->disks;
2007         int pd_idx = sh->pd_idx;
2008         int qd_idx = sh->qd_idx;
2009         struct page *xor_dest;
2010         struct page **xor_srcs = to_addr_page(percpu, 0);
2011         struct dma_async_tx_descriptor *tx;
2012         struct async_submit_ctl submit;
2013         int count;
2014         int i;
2015
2016         pr_debug("%s: stripe %llu\n", __func__,
2017                 (unsigned long long)sh->sector);
2018
2019         BUG_ON(sh->batch_head);
2020         count = 0;
2021         xor_dest = sh->dev[pd_idx].page;
2022         xor_srcs[count++] = xor_dest;
2023         for (i = disks; i--; ) {
2024                 if (i == pd_idx || i == qd_idx)
2025                         continue;
2026                 xor_srcs[count++] = sh->dev[i].page;
2027         }
2028
2029         init_async_submit(&submit, 0, NULL, NULL, NULL,
2030                           to_addr_conv(sh, percpu, 0));
2031         tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
2032                            &sh->ops.zero_sum_result, &submit);
2033
2034         atomic_inc(&sh->count);
2035         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
2036         tx = async_trigger_callback(&submit);
2037 }
2038
2039 static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
2040 {
2041         struct page **srcs = to_addr_page(percpu, 0);
2042         struct async_submit_ctl submit;
2043         int count;
2044
2045         pr_debug("%s: stripe %llu checkp: %d\n", __func__,
2046                 (unsigned long long)sh->sector, checkp);
2047
2048         BUG_ON(sh->batch_head);
2049         count = set_syndrome_sources(srcs, sh, SYNDROME_SRC_ALL);
2050         if (!checkp)
2051                 srcs[count] = NULL;
2052
2053         atomic_inc(&sh->count);
2054         init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
2055                           sh, to_addr_conv(sh, percpu, 0));
2056         async_syndrome_val(srcs, 0, count+2, STRIPE_SIZE,
2057                            &sh->ops.zero_sum_result, percpu->spare_page, &submit);
2058 }
2059
2060 static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
2061 {
2062         int overlap_clear = 0, i, disks = sh->disks;
2063         struct dma_async_tx_descriptor *tx = NULL;
2064         struct r5conf *conf = sh->raid_conf;
2065         int level = conf->level;
2066         struct raid5_percpu *percpu;
2067         unsigned long cpu;
2068
2069         cpu = get_cpu();
2070         percpu = per_cpu_ptr(conf->percpu, cpu);
2071         if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
2072                 ops_run_biofill(sh);
2073                 overlap_clear++;
2074         }
2075
2076         if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
2077                 if (level < 6)
2078                         tx = ops_run_compute5(sh, percpu);
2079                 else {
2080                         if (sh->ops.target2 < 0 || sh->ops.target < 0)
2081                                 tx = ops_run_compute6_1(sh, percpu);
2082                         else
2083                                 tx = ops_run_compute6_2(sh, percpu);
2084                 }
2085                 /* terminate the chain if reconstruct is not set to be run */
2086                 if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
2087                         async_tx_ack(tx);
2088         }
2089
2090         if (test_bit(STRIPE_OP_PREXOR, &ops_request)) {
2091                 if (level < 6)
2092                         tx = ops_run_prexor5(sh, percpu, tx);
2093                 else
2094                         tx = ops_run_prexor6(sh, percpu, tx);
2095         }
2096
2097         if (test_bit(STRIPE_OP_PARTIAL_PARITY, &ops_request))
2098                 tx = ops_run_partial_parity(sh, percpu, tx);
2099
2100         if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
2101                 tx = ops_run_biodrain(sh, tx);
2102                 overlap_clear++;
2103         }
2104
2105         if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
2106                 if (level < 6)
2107                         ops_run_reconstruct5(sh, percpu, tx);
2108                 else
2109                         ops_run_reconstruct6(sh, percpu, tx);
2110         }
2111
2112         if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
2113                 if (sh->check_state == check_state_run)
2114                         ops_run_check_p(sh, percpu);
2115                 else if (sh->check_state == check_state_run_q)
2116                         ops_run_check_pq(sh, percpu, 0);
2117                 else if (sh->check_state == check_state_run_pq)
2118                         ops_run_check_pq(sh, percpu, 1);
2119                 else
2120                         BUG();
2121         }
2122
2123         if (overlap_clear && !sh->batch_head)
2124                 for (i = disks; i--; ) {
2125                         struct r5dev *dev = &sh->dev[i];
2126                         if (test_and_clear_bit(R5_Overlap, &dev->flags))
2127                                 wake_up(&sh->raid_conf->wait_for_overlap);
2128                 }
2129         put_cpu();
2130 }
2131
2132 static void free_stripe(struct kmem_cache *sc, struct stripe_head *sh)
2133 {
2134         if (sh->ppl_page)
2135                 __free_page(sh->ppl_page);
2136         kmem_cache_free(sc, sh);
2137 }
2138
2139 static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp,
2140         int disks, struct r5conf *conf)
2141 {
2142         struct stripe_head *sh;
2143         int i;
2144
2145         sh = kmem_cache_zalloc(sc, gfp);
2146         if (sh) {
2147                 spin_lock_init(&sh->stripe_lock);
2148                 spin_lock_init(&sh->batch_lock);
2149                 INIT_LIST_HEAD(&sh->batch_list);
2150                 INIT_LIST_HEAD(&sh->lru);
2151                 INIT_LIST_HEAD(&sh->r5c);
2152                 INIT_LIST_HEAD(&sh->log_list);
2153                 atomic_set(&sh->count, 1);
2154                 sh->raid_conf = conf;
2155                 sh->log_start = MaxSector;
2156                 for (i = 0; i < disks; i++) {
2157                         struct r5dev *dev = &sh->dev[i];
2158
2159                         bio_init(&dev->req, &dev->vec, 1);
2160                         bio_init(&dev->rreq, &dev->rvec, 1);
2161                 }
2162
2163                 if (raid5_has_ppl(conf)) {
2164                         sh->ppl_page = alloc_page(gfp);
2165                         if (!sh->ppl_page) {
2166                                 free_stripe(sc, sh);
2167                                 sh = NULL;
2168                         }
2169                 }
2170         }
2171         return sh;
2172 }
2173 static int grow_one_stripe(struct r5conf *conf, gfp_t gfp)
2174 {
2175         struct stripe_head *sh;
2176
2177         sh = alloc_stripe(conf->slab_cache, gfp, conf->pool_size, conf);
2178         if (!sh)
2179                 return 0;
2180
2181         if (grow_buffers(sh, gfp)) {
2182                 shrink_buffers(sh);
2183                 free_stripe(conf->slab_cache, sh);
2184                 return 0;
2185         }
2186         sh->hash_lock_index =
2187                 conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS;
2188         /* we just created an active stripe so... */
2189         atomic_inc(&conf->active_stripes);
2190
2191         raid5_release_stripe(sh);
2192         conf->max_nr_stripes++;
2193         return 1;
2194 }
2195
2196 static int grow_stripes(struct r5conf *conf, int num)
2197 {
2198         struct kmem_cache *sc;
2199         size_t namelen = sizeof(conf->cache_name[0]);
2200         int devs = max(conf->raid_disks, conf->previous_raid_disks);
2201
2202         if (conf->mddev->gendisk)
2203                 snprintf(conf->cache_name[0], namelen,
2204                         "raid%d-%s", conf->level, mdname(conf->mddev));
2205         else
2206                 snprintf(conf->cache_name[0], namelen,
2207                         "raid%d-%p", conf->level, conf->mddev);
2208         snprintf(conf->cache_name[1], namelen, "%.27s-alt", conf->cache_name[0]);
2209
2210         conf->active_name = 0;
2211         sc = kmem_cache_create(conf->cache_name[conf->active_name],
2212                                sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
2213                                0, 0, NULL);
2214         if (!sc)
2215                 return 1;
2216         conf->slab_cache = sc;
2217         conf->pool_size = devs;
2218         while (num--)
2219                 if (!grow_one_stripe(conf, GFP_KERNEL))
2220                         return 1;
2221
2222         return 0;
2223 }
2224
2225 /**
2226  * scribble_len - return the required size of the scribble region
2227  * @num - total number of disks in the array
2228  *
2229  * The size must be enough to contain:
2230  * 1/ a struct page pointer for each device in the array +2
2231  * 2/ room to convert each entry in (1) to its corresponding dma
2232  *    (dma_map_page()) or page (page_address()) address.
2233  *
2234  * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
2235  * calculate over all devices (not just the data blocks), using zeros in place
2236  * of the P and Q blocks.
2237  */
2238 static int scribble_alloc(struct raid5_percpu *percpu,
2239                           int num, int cnt, gfp_t flags)
2240 {
2241         size_t obj_size =
2242                 sizeof(struct page *) * (num+2) +
2243                 sizeof(addr_conv_t) * (num+2);
2244         void *scribble;
2245
2246         scribble = kvmalloc_array(cnt, obj_size, flags);
2247         if (!scribble)
2248                 return -ENOMEM;
2249
2250         kvfree(percpu->scribble);
2251
2252         percpu->scribble = scribble;
2253         percpu->scribble_obj_size = obj_size;
2254         return 0;
2255 }
2256
2257 static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
2258 {
2259         unsigned long cpu;
2260         int err = 0;
2261
2262         /*
2263          * Never shrink. And mddev_suspend() could deadlock if this is called
2264          * from raid5d. In that case, scribble_disks and scribble_sectors
2265          * should equal to new_disks and new_sectors
2266          */
2267         if (conf->scribble_disks >= new_disks &&
2268             conf->scribble_sectors >= new_sectors)
2269                 return 0;
2270         mddev_suspend(conf->mddev);
2271         get_online_cpus();
2272
2273         for_each_present_cpu(cpu) {
2274                 struct raid5_percpu *percpu;
2275
2276                 percpu = per_cpu_ptr(conf->percpu, cpu);
2277                 err = scribble_alloc(percpu, new_disks,
2278                                      new_sectors / STRIPE_SECTORS,
2279                                      GFP_NOIO);
2280                 if (err)
2281                         break;
2282         }
2283
2284         put_online_cpus();
2285         mddev_resume(conf->mddev);
2286         if (!err) {
2287                 conf->scribble_disks = new_disks;
2288                 conf->scribble_sectors = new_sectors;
2289         }
2290         return err;
2291 }
2292
2293 static int resize_stripes(struct r5conf *conf, int newsize)
2294 {
2295         /* Make all the stripes able to hold 'newsize' devices.
2296          * New slots in each stripe get 'page' set to a new page.
2297          *
2298          * This happens in stages:
2299          * 1/ create a new kmem_cache and allocate the required number of
2300          *    stripe_heads.
2301          * 2/ gather all the old stripe_heads and transfer the pages across
2302          *    to the new stripe_heads.  This will have the side effect of
2303          *    freezing the array as once all stripe_heads have been collected,
2304          *    no IO will be possible.  Old stripe heads are freed once their
2305          *    pages have been transferred over, and the old kmem_cache is
2306          *    freed when all stripes are done.
2307          * 3/ reallocate conf->disks to be suitable bigger.  If this fails,
2308          *    we simple return a failure status - no need to clean anything up.
2309          * 4/ allocate new pages for the new slots in the new stripe_heads.
2310          *    If this fails, we don't bother trying the shrink the
2311          *    stripe_heads down again, we just leave them as they are.
2312          *    As each stripe_head is processed the new one is released into
2313          *    active service.
2314          *
2315          * Once step2 is started, we cannot afford to wait for a write,
2316          * so we use GFP_NOIO allocations.
2317          */
2318         struct stripe_head *osh, *nsh;
2319         LIST_HEAD(newstripes);
2320         struct disk_info *ndisks;
2321         int err = 0;
2322         struct kmem_cache *sc;
2323         int i;
2324         int hash, cnt;
2325
2326         md_allow_write(conf->mddev);
2327
2328         /* Step 1 */
2329         sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
2330                                sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
2331                                0, 0, NULL);
2332         if (!sc)
2333                 return -ENOMEM;
2334
2335         /* Need to ensure auto-resizing doesn't interfere */
2336         mutex_lock(&conf->cache_size_mutex);
2337
2338         for (i = conf->max_nr_stripes; i; i--) {
2339                 nsh = alloc_stripe(sc, GFP_KERNEL, newsize, conf);
2340                 if (!nsh)
2341                         break;
2342
2343                 list_add(&nsh->lru, &newstripes);
2344         }
2345         if (i) {
2346                 /* didn't get enough, give up */
2347                 while (!list_empty(&newstripes)) {
2348                         nsh = list_entry(newstripes.next, struct stripe_head, lru);
2349                         list_del(&nsh->lru);
2350                         free_stripe(sc, nsh);
2351                 }
2352                 kmem_cache_destroy(sc);
2353                 mutex_unlock(&conf->cache_size_mutex);
2354                 return -ENOMEM;
2355         }
2356         /* Step 2 - Must use GFP_NOIO now.
2357          * OK, we have enough stripes, start collecting inactive
2358          * stripes and copying them over
2359          */
2360         hash = 0;
2361         cnt = 0;
2362         list_for_each_entry(nsh, &newstripes, lru) {
2363                 lock_device_hash_lock(conf, hash);
2364                 wait_event_cmd(conf->wait_for_stripe,
2365                                     !list_empty(conf->inactive_list + hash),
2366                                     unlock_device_hash_lock(conf, hash),
2367                                     lock_device_hash_lock(conf, hash));
2368                 osh = get_free_stripe(conf, hash);
2369                 unlock_device_hash_lock(conf, hash);
2370
2371                 for(i=0; i<conf->pool_size; i++) {
2372                         nsh->dev[i].page = osh->dev[i].page;
2373                         nsh->dev[i].orig_page = osh->dev[i].page;
2374                 }
2375                 nsh->hash_lock_index = hash;
2376                 free_stripe(conf->slab_cache, osh);
2377                 cnt++;
2378                 if (cnt >= conf->max_nr_stripes / NR_STRIPE_HASH_LOCKS +
2379                     !!((conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS) > hash)) {
2380                         hash++;
2381                         cnt = 0;
2382                 }
2383         }
2384         kmem_cache_destroy(conf->slab_cache);
2385
2386         /* Step 3.
2387          * At this point, we are holding all the stripes so the array
2388          * is completely stalled, so now is a good time to resize
2389          * conf->disks and the scribble region
2390          */
2391         ndisks = kcalloc(newsize, sizeof(struct disk_info), GFP_NOIO);
2392         if (ndisks) {
2393                 for (i = 0; i < conf->pool_size; i++)
2394                         ndisks[i] = conf->disks[i];
2395
2396                 for (i = conf->pool_size; i < newsize; i++) {
2397                         ndisks[i].extra_page = alloc_page(GFP_NOIO);
2398                         if (!ndisks[i].extra_page)
2399                                 err = -ENOMEM;
2400                 }
2401
2402                 if (err) {
2403                         for (i = conf->pool_size; i < newsize; i++)
2404                                 if (ndisks[i].extra_page)
2405                                         put_page(ndisks[i].extra_page);
2406                         kfree(ndisks);
2407                 } else {
2408                         kfree(conf->disks);
2409                         conf->disks = ndisks;
2410                 }
2411         } else
2412                 err = -ENOMEM;
2413
2414         mutex_unlock(&conf->cache_size_mutex);
2415
2416         conf->slab_cache = sc;
2417         conf->active_name = 1-conf->active_name;
2418
2419         /* Step 4, return new stripes to service */
2420         while(!list_empty(&newstripes)) {
2421                 nsh = list_entry(newstripes.next, struct stripe_head, lru);
2422                 list_del_init(&nsh->lru);
2423
2424                 for (i=conf->raid_disks; i < newsize; i++)
2425                         if (nsh->dev[i].page == NULL) {
2426                                 struct page *p = alloc_page(GFP_NOIO);
2427                                 nsh->dev[i].page = p;
2428                                 nsh->dev[i].orig_page = p;
2429                                 if (!p)
2430                                         err = -ENOMEM;
2431                         }
2432                 raid5_release_stripe(nsh);
2433         }
2434         /* critical section pass, GFP_NOIO no longer needed */
2435
2436         if (!err)
2437                 conf->pool_size = newsize;
2438         return err;
2439 }
2440
2441 static int drop_one_stripe(struct r5conf *conf)
2442 {
2443         struct stripe_head *sh;
2444         int hash = (conf->max_nr_stripes - 1) & STRIPE_HASH_LOCKS_MASK;
2445
2446         spin_lock_irq(conf->hash_locks + hash);
2447         sh = get_free_stripe(conf, hash);
2448         spin_unlock_irq(conf->hash_locks + hash);
2449         if (!sh)
2450                 return 0;
2451         BUG_ON(atomic_read(&sh->count));
2452         shrink_buffers(sh);
2453         free_stripe(conf->slab_cache, sh);
2454         atomic_dec(&conf->active_stripes);
2455         conf->max_nr_stripes--;
2456         return 1;
2457 }
2458
2459 static void shrink_stripes(struct r5conf *conf)
2460 {
2461         while (conf->max_nr_stripes &&
2462                drop_one_stripe(conf))
2463                 ;
2464
2465         kmem_cache_destroy(conf->slab_cache);
2466         conf->slab_cache = NULL;
2467 }
2468
2469 static void raid5_end_read_request(struct bio * bi)
2470 {
2471         struct stripe_head *sh = bi->bi_private;
2472         struct r5conf *conf = sh->raid_conf;
2473         int disks = sh->disks, i;
2474         char b[BDEVNAME_SIZE];
2475         struct md_rdev *rdev = NULL;
2476         sector_t s;
2477
2478         for (i=0 ; i<disks; i++)
2479                 if (bi == &sh->dev[i].req)
2480                         break;
2481
2482         pr_debug("end_read_request %llu/%d, count: %d, error %d.\n",
2483                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2484                 bi->bi_status);
2485         if (i == disks) {
2486                 bio_reset(bi);
2487                 BUG();
2488                 return;
2489         }
2490         if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2491                 /* If replacement finished while this request was outstanding,
2492                  * 'replacement' might be NULL already.
2493                  * In that case it moved down to 'rdev'.
2494                  * rdev is not removed until all requests are finished.
2495                  */
2496                 rdev = conf->disks[i].replacement;
2497         if (!rdev)
2498                 rdev = conf->disks[i].rdev;
2499
2500         if (use_new_offset(conf, sh))
2501                 s = sh->sector + rdev->new_data_offset;
2502         else
2503                 s = sh->sector + rdev->data_offset;
2504         if (!bi->bi_status) {
2505                 set_bit(R5_UPTODATE, &sh->dev[i].flags);
2506                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2507                         /* Note that this cannot happen on a
2508                          * replacement device.  We just fail those on
2509                          * any error
2510                          */
2511                         pr_info_ratelimited(
2512                                 "md/raid:%s: read error corrected (%lu sectors at %llu on %s)\n",
2513                                 mdname(conf->mddev), STRIPE_SECTORS,
2514                                 (unsigned long long)s,
2515                                 bdevname(rdev->bdev, b));
2516                         atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
2517                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2518                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2519                 } else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2520                         clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2521
2522                 if (test_bit(R5_InJournal, &sh->dev[i].flags))
2523                         /*
2524                          * end read for a page in journal, this
2525                          * must be preparing for prexor in rmw
2526                          */
2527                         set_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags);
2528
2529                 if (atomic_read(&rdev->read_errors))
2530                         atomic_set(&rdev->read_errors, 0);
2531         } else {
2532                 const char *bdn = bdevname(rdev->bdev, b);
2533                 int retry = 0;
2534                 int set_bad = 0;
2535
2536                 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
2537                 atomic_inc(&rdev->read_errors);
2538                 if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2539                         pr_warn_ratelimited(
2540                                 "md/raid:%s: read error on replacement device (sector %llu on %s).\n",
2541                                 mdname(conf->mddev),
2542                                 (unsigned long long)s,
2543                                 bdn);
2544                 else if (conf->mddev->degraded >= conf->max_degraded) {
2545                         set_bad = 1;
2546                         pr_warn_ratelimited(
2547                                 "md/raid:%s: read error not correctable (sector %llu on %s).\n",
2548                                 mdname(conf->mddev),
2549                                 (unsigned long long)s,
2550                                 bdn);
2551                 } else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
2552                         /* Oh, no!!! */
2553                         set_bad = 1;
2554                         pr_warn_ratelimited(
2555                                 "md/raid:%s: read error NOT corrected!! (sector %llu on %s).\n",
2556                                 mdname(conf->mddev),
2557                                 (unsigned long long)s,
2558                                 bdn);
2559                 } else if (atomic_read(&rdev->read_errors)
2560                          > conf->max_nr_stripes)
2561                         pr_warn("md/raid:%s: Too many read errors, failing device %s.\n",
2562                                mdname(conf->mddev), bdn);
2563                 else
2564                         retry = 1;
2565                 if (set_bad && test_bit(In_sync, &rdev->flags)
2566                     && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2567                         retry = 1;
2568                 if (retry)
2569                         if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
2570                                 set_bit(R5_ReadError, &sh->dev[i].flags);
2571                                 clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2572                         } else
2573                                 set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2574                 else {
2575                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2576                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2577                         if (!(set_bad
2578                               && test_bit(In_sync, &rdev->flags)
2579                               && rdev_set_badblocks(
2580                                       rdev, sh->sector, STRIPE_SECTORS, 0)))
2581                                 md_error(conf->mddev, rdev);
2582                 }
2583         }
2584         rdev_dec_pending(rdev, conf->mddev);
2585         bio_reset(bi);
2586         clear_bit(R5_LOCKED, &sh->dev[i].flags);
2587         set_bit(STRIPE_HANDLE, &sh->state);
2588         raid5_release_stripe(sh);
2589 }
2590
2591 static void raid5_end_write_request(struct bio *bi)
2592 {
2593         struct stripe_head *sh = bi->bi_private;
2594         struct r5conf *conf = sh->raid_conf;
2595         int disks = sh->disks, i;
2596         struct md_rdev *uninitialized_var(rdev);
2597         sector_t first_bad;
2598         int bad_sectors;
2599         int replacement = 0;
2600
2601         for (i = 0 ; i < disks; i++) {
2602                 if (bi == &sh->dev[i].req) {
2603                         rdev = conf->disks[i].rdev;
2604                         break;
2605                 }
2606                 if (bi == &sh->dev[i].rreq) {
2607                         rdev = conf->disks[i].replacement;
2608                         if (rdev)
2609                                 replacement = 1;
2610                         else
2611                                 /* rdev was removed and 'replacement'
2612                                  * replaced it.  rdev is not removed
2613                                  * until all requests are finished.
2614                                  */
2615                                 rdev = conf->disks[i].rdev;
2616                         break;
2617                 }
2618         }
2619         pr_debug("end_write_request %llu/%d, count %d, error: %d.\n",
2620                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2621                 bi->bi_status);
2622         if (i == disks) {
2623                 bio_reset(bi);
2624                 BUG();
2625                 return;
2626         }
2627
2628         if (replacement) {
2629                 if (bi->bi_status)
2630                         md_error(conf->mddev, rdev);
2631                 else if (is_badblock(rdev, sh->sector,
2632                                      STRIPE_SECTORS,
2633                                      &first_bad, &bad_sectors))
2634                         set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
2635         } else {
2636                 if (bi->bi_status) {
2637                         set_bit(STRIPE_DEGRADED, &sh->state);
2638                         set_bit(WriteErrorSeen, &rdev->flags);
2639                         set_bit(R5_WriteError, &sh->dev[i].flags);
2640                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
2641                                 set_bit(MD_RECOVERY_NEEDED,
2642                                         &rdev->mddev->recovery);
2643                 } else if (is_badblock(rdev, sh->sector,
2644                                        STRIPE_SECTORS,
2645                                        &first_bad, &bad_sectors)) {
2646                         set_bit(R5_MadeGood, &sh->dev[i].flags);
2647                         if (test_bit(R5_ReadError, &sh->dev[i].flags))
2648                                 /* That was a successful write so make
2649                                  * sure it looks like we already did
2650                                  * a re-write.
2651                                  */
2652                                 set_bit(R5_ReWrite, &sh->dev[i].flags);
2653                 }
2654         }
2655         rdev_dec_pending(rdev, conf->mddev);
2656
2657         if (sh->batch_head && bi->bi_status && !replacement)
2658                 set_bit(STRIPE_BATCH_ERR, &sh->batch_head->state);
2659
2660         bio_reset(bi);
2661         if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
2662                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
2663         set_bit(STRIPE_HANDLE, &sh->state);
2664         raid5_release_stripe(sh);
2665
2666         if (sh->batch_head && sh != sh->batch_head)
2667                 raid5_release_stripe(sh->batch_head);
2668 }
2669
2670 static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
2671 {
2672         char b[BDEVNAME_SIZE];
2673         struct r5conf *conf = mddev->private;
2674         unsigned long flags;
2675         pr_debug("raid456: error called\n");
2676
2677         spin_lock_irqsave(&conf->device_lock, flags);
2678
2679         if (test_bit(In_sync, &rdev->flags) &&
2680             mddev->degraded == conf->max_degraded) {
2681                 /*
2682                  * Don't allow to achieve failed state
2683                  * Don't try to recover this device
2684                  */
2685                 conf->recovery_disabled = mddev->recovery_disabled;
2686                 spin_unlock_irqrestore(&conf->device_lock, flags);
2687                 return;
2688         }
2689
2690         set_bit(Faulty, &rdev->flags);
2691         clear_bit(In_sync, &rdev->flags);
2692         mddev->degraded = raid5_calc_degraded(conf);
2693         spin_unlock_irqrestore(&conf->device_lock, flags);
2694         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2695
2696         set_bit(Blocked, &rdev->flags);
2697         set_mask_bits(&mddev->sb_flags, 0,
2698                       BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
2699         pr_crit("md/raid:%s: Disk failure on %s, disabling device.\n"
2700                 "md/raid:%s: Operation continuing on %d devices.\n",
2701                 mdname(mddev),
2702                 bdevname(rdev->bdev, b),
2703                 mdname(mddev),
2704                 conf->raid_disks - mddev->degraded);
2705         r5c_update_on_rdev_error(mddev, rdev);
2706 }
2707
2708 /*
2709  * Input: a 'big' sector number,
2710  * Output: index of the data and parity disk, and the sector # in them.
2711  */
2712 sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
2713                               int previous, int *dd_idx,
2714                               struct stripe_head *sh)
2715 {
2716         sector_t stripe, stripe2;
2717         sector_t chunk_number;
2718         unsigned int chunk_offset;
2719         int pd_idx, qd_idx;
2720         int ddf_layout = 0;
2721         sector_t new_sector;
2722         int algorithm = previous ? conf->prev_algo
2723                                  : conf->algorithm;
2724         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2725                                          : conf->chunk_sectors;
2726         int raid_disks = previous ? conf->previous_raid_disks
2727                                   : conf->raid_disks;
2728         int data_disks = raid_disks - conf->max_degraded;
2729
2730         /* First compute the information on this sector */
2731
2732         /*
2733          * Compute the chunk number and the sector offset inside the chunk
2734          */
2735         chunk_offset = sector_div(r_sector, sectors_per_chunk);
2736         chunk_number = r_sector;
2737
2738         /*
2739          * Compute the stripe number
2740          */
2741         stripe = chunk_number;
2742         *dd_idx = sector_div(stripe, data_disks);
2743         stripe2 = stripe;
2744         /*
2745          * Select the parity disk based on the user selected algorithm.
2746          */
2747         pd_idx = qd_idx = -1;
2748         switch(conf->level) {
2749         case 4:
2750                 pd_idx = data_disks;
2751                 break;
2752         case 5:
2753                 switch (algorithm) {
2754                 case ALGORITHM_LEFT_ASYMMETRIC:
2755                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
2756                         if (*dd_idx >= pd_idx)
2757                                 (*dd_idx)++;
2758                         break;
2759                 case ALGORITHM_RIGHT_ASYMMETRIC:
2760                         pd_idx = sector_div(stripe2, raid_disks);
2761                         if (*dd_idx >= pd_idx)
2762                                 (*dd_idx)++;
2763                         break;
2764                 case ALGORITHM_LEFT_SYMMETRIC:
2765                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
2766                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2767                         break;
2768                 case ALGORITHM_RIGHT_SYMMETRIC:
2769                         pd_idx = sector_div(stripe2, raid_disks);
2770                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2771                         break;
2772                 case ALGORITHM_PARITY_0:
2773                         pd_idx = 0;
2774                         (*dd_idx)++;
2775                         break;
2776                 case ALGORITHM_PARITY_N:
2777                         pd_idx = data_disks;
2778                         break;
2779                 default:
2780                         BUG();
2781                 }
2782                 break;
2783         case 6:
2784
2785                 switch (algorithm) {
2786                 case ALGORITHM_LEFT_ASYMMETRIC:
2787                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2788                         qd_idx = pd_idx + 1;
2789                         if (pd_idx == raid_disks-1) {
2790                                 (*dd_idx)++;    /* Q D D D P */
2791                                 qd_idx = 0;
2792                         } else if (*dd_idx >= pd_idx)
2793                                 (*dd_idx) += 2; /* D D P Q D */
2794                         break;
2795                 case ALGORITHM_RIGHT_ASYMMETRIC:
2796                         pd_idx = sector_div(stripe2, raid_disks);
2797                         qd_idx = pd_idx + 1;
2798                         if (pd_idx == raid_disks-1) {
2799                                 (*dd_idx)++;    /* Q D D D P */
2800                                 qd_idx = 0;
2801                         } else if (*dd_idx >= pd_idx)
2802                                 (*dd_idx) += 2; /* D D P Q D */
2803                         break;
2804                 case ALGORITHM_LEFT_SYMMETRIC:
2805                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2806                         qd_idx = (pd_idx + 1) % raid_disks;
2807                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2808                         break;
2809                 case ALGORITHM_RIGHT_SYMMETRIC:
2810                         pd_idx = sector_div(stripe2, raid_disks);
2811                         qd_idx = (pd_idx + 1) % raid_disks;
2812                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2813                         break;
2814
2815                 case ALGORITHM_PARITY_0:
2816                         pd_idx = 0;
2817                         qd_idx = 1;
2818                         (*dd_idx) += 2;
2819                         break;
2820                 case ALGORITHM_PARITY_N:
2821                         pd_idx = data_disks;
2822                         qd_idx = data_disks + 1;
2823                         break;
2824
2825                 case ALGORITHM_ROTATING_ZERO_RESTART:
2826                         /* Exactly the same as RIGHT_ASYMMETRIC, but or
2827                          * of blocks for computing Q is different.
2828                          */
2829                         pd_idx = sector_div(stripe2, raid_disks);
2830                         qd_idx = pd_idx + 1;
2831                         if (pd_idx == raid_disks-1) {
2832                                 (*dd_idx)++;    /* Q D D D P */
2833                                 qd_idx = 0;
2834                         } else if (*dd_idx >= pd_idx)
2835                                 (*dd_idx) += 2; /* D D P Q D */
2836                         ddf_layout = 1;
2837                         break;
2838
2839                 case ALGORITHM_ROTATING_N_RESTART:
2840                         /* Same a left_asymmetric, by first stripe is
2841                          * D D D P Q  rather than
2842                          * Q D D D P
2843                          */
2844                         stripe2 += 1;
2845                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2846                         qd_idx = pd_idx + 1;
2847                         if (pd_idx == raid_disks-1) {
2848                                 (*dd_idx)++;    /* Q D D D P */
2849                                 qd_idx = 0;
2850                         } else if (*dd_idx >= pd_idx)
2851                                 (*dd_idx) += 2; /* D D P Q D */
2852                         ddf_layout = 1;
2853                         break;
2854
2855                 case ALGORITHM_ROTATING_N_CONTINUE:
2856                         /* Same as left_symmetric but Q is before P */
2857                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2858                         qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
2859                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2860                         ddf_layout = 1;
2861                         break;
2862
2863                 case ALGORITHM_LEFT_ASYMMETRIC_6:
2864                         /* RAID5 left_asymmetric, with Q on last device */
2865                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2866                         if (*dd_idx >= pd_idx)
2867                                 (*dd_idx)++;
2868                         qd_idx = raid_disks - 1;
2869                         break;
2870
2871                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
2872                         pd_idx = sector_div(stripe2, raid_disks-1);
2873                         if (*dd_idx >= pd_idx)
2874                                 (*dd_idx)++;
2875                         qd_idx = raid_disks - 1;
2876                         break;
2877
2878                 case ALGORITHM_LEFT_SYMMETRIC_6:
2879                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2880                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2881                         qd_idx = raid_disks - 1;
2882                         break;
2883
2884                 case ALGORITHM_RIGHT_SYMMETRIC_6:
2885                         pd_idx = sector_div(stripe2, raid_disks-1);
2886                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2887                         qd_idx = raid_disks - 1;
2888                         break;
2889
2890                 case ALGORITHM_PARITY_0_6:
2891                         pd_idx = 0;
2892                         (*dd_idx)++;
2893                         qd_idx = raid_disks - 1;
2894                         break;
2895
2896                 default:
2897                         BUG();
2898                 }
2899                 break;
2900         }
2901
2902         if (sh) {
2903                 sh->pd_idx = pd_idx;
2904                 sh->qd_idx = qd_idx;
2905                 sh->ddf_layout = ddf_layout;
2906         }
2907         /*
2908          * Finally, compute the new sector number
2909          */
2910         new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
2911         return new_sector;
2912 }
2913
2914 sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous)
2915 {
2916         struct r5conf *conf = sh->raid_conf;
2917         int raid_disks = sh->disks;
2918         int data_disks = raid_disks - conf->max_degraded;
2919         sector_t new_sector = sh->sector, check;
2920         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2921                                          : conf->chunk_sectors;
2922         int algorithm = previous ? conf->prev_algo
2923                                  : conf->algorithm;
2924         sector_t stripe;
2925         int chunk_offset;
2926         sector_t chunk_number;
2927         int dummy1, dd_idx = i;
2928         sector_t r_sector;
2929         struct stripe_head sh2;
2930
2931         chunk_offset = sector_div(new_sector, sectors_per_chunk);
2932         stripe = new_sector;
2933
2934         if (i == sh->pd_idx)
2935                 return 0;
2936         switch(conf->level) {
2937         case 4: break;
2938         case 5:
2939                 switch (algorithm) {
2940                 case ALGORITHM_LEFT_ASYMMETRIC:
2941                 case ALGORITHM_RIGHT_ASYMMETRIC:
2942                         if (i > sh->pd_idx)
2943                                 i--;
2944                         break;
2945                 case ALGORITHM_LEFT_SYMMETRIC:
2946                 case ALGORITHM_RIGHT_SYMMETRIC:
2947                         if (i < sh->pd_idx)
2948                                 i += raid_disks;
2949                         i -= (sh->pd_idx + 1);
2950                         break;
2951                 case ALGORITHM_PARITY_0:
2952                         i -= 1;
2953                         break;
2954                 case ALGORITHM_PARITY_N:
2955                         break;
2956                 default:
2957                         BUG();
2958                 }
2959                 break;
2960         case 6:
2961                 if (i == sh->qd_idx)
2962                         return 0; /* It is the Q disk */
2963                 switch (algorithm) {
2964                 case ALGORITHM_LEFT_ASYMMETRIC:
2965                 case ALGORITHM_RIGHT_ASYMMETRIC:
2966                 case ALGORITHM_ROTATING_ZERO_RESTART:
2967                 case ALGORITHM_ROTATING_N_RESTART:
2968                         if (sh->pd_idx == raid_disks-1)
2969                                 i--;    /* Q D D D P */
2970                         else if (i > sh->pd_idx)
2971                                 i -= 2; /* D D P Q D */
2972                         break;
2973                 case ALGORITHM_LEFT_SYMMETRIC:
2974                 case ALGORITHM_RIGHT_SYMMETRIC:
2975                         if (sh->pd_idx == raid_disks-1)
2976                                 i--; /* Q D D D P */
2977                         else {
2978                                 /* D D P Q D */
2979                                 if (i < sh->pd_idx)
2980                                         i += raid_disks;
2981                                 i -= (sh->pd_idx + 2);
2982                         }
2983                         break;
2984                 case ALGORITHM_PARITY_0:
2985                         i -= 2;
2986                         break;
2987                 case ALGORITHM_PARITY_N:
2988                         break;
2989                 case ALGORITHM_ROTATING_N_CONTINUE:
2990                         /* Like left_symmetric, but P is before Q */
2991                         if (sh->pd_idx == 0)
2992                                 i--;    /* P D D D Q */
2993                         else {
2994                                 /* D D Q P D */
2995                                 if (i < sh->pd_idx)
2996                                         i += raid_disks;
2997                                 i -= (sh->pd_idx + 1);
2998                         }
2999                         break;
3000                 case ALGORITHM_LEFT_ASYMMETRIC_6:
3001                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
3002                         if (i > sh->pd_idx)
3003                                 i--;
3004                         break;
3005                 case ALGORITHM_LEFT_SYMMETRIC_6:
3006                 case ALGORITHM_RIGHT_SYMMETRIC_6:
3007                         if (i < sh->pd_idx)
3008                                 i += data_disks + 1;
3009                         i -= (sh->pd_idx + 1);
3010                         break;
3011                 case ALGORITHM_PARITY_0_6:
3012                         i -= 1;
3013                         break;
3014                 default:
3015                         BUG();
3016                 }
3017                 break;
3018         }
3019
3020         chunk_number = stripe * data_disks + i;
3021         r_sector = chunk_number * sectors_per_chunk + chunk_offset;
3022
3023         check = raid5_compute_sector(conf, r_sector,
3024                                      previous, &dummy1, &sh2);
3025         if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
3026                 || sh2.qd_idx != sh->qd_idx) {
3027                 pr_warn("md/raid:%s: compute_blocknr: map not correct\n",
3028                         mdname(conf->mddev));
3029                 return 0;
3030         }
3031         return r_sector;
3032 }
3033
3034 /*
3035  * There are cases where we want handle_stripe_dirtying() and
3036  * schedule_reconstruction() to delay towrite to some dev of a stripe.
3037  *
3038  * This function checks whether we want to delay the towrite. Specifically,
3039  * we delay the towrite when:
3040  *
3041  *   1. degraded stripe has a non-overwrite to the missing dev, AND this
3042  *      stripe has data in journal (for other devices).
3043  *
3044  *      In this case, when reading data for the non-overwrite dev, it is
3045  *      necessary to handle complex rmw of write back cache (prexor with
3046  *      orig_page, and xor with page). To keep read path simple, we would
3047  *      like to flush data in journal to RAID disks first, so complex rmw
3048  *      is handled in the write patch (handle_stripe_dirtying).
3049  *
3050  *   2. when journal space is critical (R5C_LOG_CRITICAL=1)
3051  *
3052  *      It is important to be able to flush all stripes in raid5-cache.
3053  *      Therefore, we need reserve some space on the journal device for
3054  *      these flushes. If flush operation includes pending writes to the
3055  *      stripe, we need to reserve (conf->raid_disk + 1) pages per stripe
3056  *      for the flush out. If we exclude these pending writes from flush
3057  *      operation, we only need (conf->max_degraded + 1) pages per stripe.
3058  *      Therefore, excluding pending writes in these cases enables more
3059  *      efficient use of the journal device.
3060  *
3061  *      Note: To make sure the stripe makes progress, we only delay
3062  *      towrite for stripes with data already in journal (injournal > 0).
3063  *      When LOG_CRITICAL, stripes with injournal == 0 will be sent to
3064  *      no_space_stripes list.
3065  *
3066  *   3. during journal failure
3067  *      In journal failure, we try to flush all cached data to raid disks
3068  *      based on data in stripe cache. The array is read-only to upper
3069  *      layers, so we would skip all pending writes.
3070  *
3071  */
3072 static inline bool delay_towrite(struct r5conf *conf,
3073                                  struct r5dev *dev,
3074                                  struct stripe_head_state *s)
3075 {
3076         /* case 1 above */
3077         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3078             !test_bit(R5_Insync, &dev->flags) && s->injournal)
3079                 return true;
3080         /* case 2 above */
3081         if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
3082             s->injournal > 0)
3083                 return true;
3084         /* case 3 above */
3085         if (s->log_failed && s->injournal)
3086                 return true;
3087         return false;
3088 }
3089
3090 static void
3091 schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
3092                          int rcw, int expand)
3093 {
3094         int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx, disks = sh->disks;
3095         struct r5conf *conf = sh->raid_conf;
3096         int level = conf->level;
3097
3098         if (rcw) {
3099                 /*
3100                  * In some cases, handle_stripe_dirtying initially decided to
3101                  * run rmw and allocates extra page for prexor. However, rcw is
3102                  * cheaper later on. We need to free the extra page now,
3103                  * because we won't be able to do that in ops_complete_prexor().
3104                  */
3105                 r5c_release_extra_page(sh);
3106
3107                 for (i = disks; i--; ) {
3108                         struct r5dev *dev = &sh->dev[i];
3109
3110                         if (dev->towrite && !delay_towrite(conf, dev, s)) {
3111                                 set_bit(R5_LOCKED, &dev->flags);
3112                                 set_bit(R5_Wantdrain, &dev->flags);
3113                                 if (!expand)
3114                                         clear_bit(R5_UPTODATE, &dev->flags);
3115                                 s->locked++;
3116                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3117                                 set_bit(R5_LOCKED, &dev->flags);
3118                                 s->locked++;
3119                         }
3120                 }
3121                 /* if we are not expanding this is a proper write request, and
3122                  * there will be bios with new data to be drained into the
3123                  * stripe cache
3124                  */
3125                 if (!expand) {
3126                         if (!s->locked)
3127                                 /* False alarm, nothing to do */
3128                                 return;
3129                         sh->reconstruct_state = reconstruct_state_drain_run;
3130                         set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3131                 } else
3132                         sh->reconstruct_state = reconstruct_state_run;
3133
3134                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3135
3136                 if (s->locked + conf->max_degraded == disks)
3137                         if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
3138                                 atomic_inc(&conf->pending_full_writes);
3139         } else {
3140                 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
3141                         test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
3142                 BUG_ON(level == 6 &&
3143                         (!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
3144                            test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));
3145
3146                 for (i = disks; i--; ) {
3147                         struct r5dev *dev = &sh->dev[i];
3148                         if (i == pd_idx || i == qd_idx)
3149                                 continue;
3150
3151                         if (dev->towrite &&
3152                             (test_bit(R5_UPTODATE, &dev->flags) ||
3153                              test_bit(R5_Wantcompute, &dev->flags))) {
3154                                 set_bit(R5_Wantdrain, &dev->flags);
3155                                 set_bit(R5_LOCKED, &dev->flags);
3156                                 clear_bit(R5_UPTODATE, &dev->flags);
3157                                 s->locked++;
3158                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3159                                 set_bit(R5_LOCKED, &dev->flags);
3160                                 s->locked++;
3161                         }
3162                 }
3163                 if (!s->locked)
3164                         /* False alarm - nothing to do */
3165                         return;
3166                 sh->reconstruct_state = reconstruct_state_prexor_drain_run;
3167                 set_bit(STRIPE_OP_PREXOR, &s->ops_request);
3168                 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3169                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3170         }
3171
3172         /* keep the parity disk(s) locked while asynchronous operations
3173          * are in flight
3174          */
3175         set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
3176         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
3177         s->locked++;
3178
3179         if (level == 6) {
3180                 int qd_idx = sh->qd_idx;
3181                 struct r5dev *dev = &sh->dev[qd_idx];
3182
3183                 set_bit(R5_LOCKED, &dev->flags);
3184                 clear_bit(R5_UPTODATE, &dev->flags);
3185                 s->locked++;
3186         }
3187
3188         if (raid5_has_ppl(sh->raid_conf) && sh->ppl_page &&
3189             test_bit(STRIPE_OP_BIODRAIN, &s->ops_request) &&
3190             !test_bit(STRIPE_FULL_WRITE, &sh->state) &&
3191             test_bit(R5_Insync, &sh->dev[pd_idx].flags))
3192                 set_bit(STRIPE_OP_PARTIAL_PARITY, &s->ops_request);
3193
3194         pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
3195                 __func__, (unsigned long long)sh->sector,
3196                 s->locked, s->ops_request);
3197 }
3198
3199 /*
3200  * Each stripe/dev can have one or more bion attached.
3201  * toread/towrite point to the first in a chain.
3202  * The bi_next chain must be in order.
3203  */
3204 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx,
3205                           int forwrite, int previous)
3206 {
3207         struct bio **bip;
3208         struct r5conf *conf = sh->raid_conf;
3209         int firstwrite=0;
3210
3211         pr_debug("adding bi b#%llu to stripe s#%llu\n",
3212                 (unsigned long long)bi->bi_iter.bi_sector,
3213                 (unsigned long long)sh->sector);
3214
3215         spin_lock_irq(&sh->stripe_lock);
3216         sh->dev[dd_idx].write_hint = bi->bi_write_hint;
3217         /* Don't allow new IO added to stripes in batch list */
3218         if (sh->batch_head)
3219                 goto overlap;
3220         if (forwrite) {
3221                 bip = &sh->dev[dd_idx].towrite;
3222                 if (*bip == NULL)
3223                         firstwrite = 1;
3224         } else
3225                 bip = &sh->dev[dd_idx].toread;
3226         while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector) {
3227                 if (bio_end_sector(*bip) > bi->bi_iter.bi_sector)
3228                         goto overlap;
3229                 bip = & (*bip)->bi_next;
3230         }
3231         if (*bip && (*bip)->bi_iter.bi_sector < bio_end_sector(bi))
3232                 goto overlap;
3233
3234         if (forwrite && raid5_has_ppl(conf)) {
3235                 /*
3236                  * With PPL only writes to consecutive data chunks within a
3237                  * stripe are allowed because for a single stripe_head we can
3238                  * only have one PPL entry at a time, which describes one data
3239                  * range. Not really an overlap, but wait_for_overlap can be
3240                  * used to handle this.
3241                  */
3242                 sector_t sector;
3243                 sector_t first = 0;
3244                 sector_t last = 0;
3245                 int count = 0;
3246                 int i;
3247
3248                 for (i = 0; i < sh->disks; i++) {
3249                         if (i != sh->pd_idx &&
3250                             (i == dd_idx || sh->dev[i].towrite)) {
3251                                 sector = sh->dev[i].sector;
3252                                 if (count == 0 || sector < first)
3253                                         first = sector;
3254                                 if (sector > last)
3255                                         last = sector;
3256                                 count++;
3257                         }
3258                 }
3259
3260                 if (first + conf->chunk_sectors * (count - 1) != last)
3261                         goto overlap;
3262         }
3263
3264         if (!forwrite || previous)
3265                 clear_bit(STRIPE_BATCH_READY, &sh->state);
3266
3267         BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
3268         if (*bip)
3269                 bi->bi_next = *bip;
3270         *bip = bi;
3271         bio_inc_remaining(bi);
3272         md_write_inc(conf->mddev, bi);
3273
3274         if (forwrite) {
3275                 /* check if page is covered */
3276                 sector_t sector = sh->dev[dd_idx].sector;
3277                 for (bi=sh->dev[dd_idx].towrite;
3278                      sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
3279                              bi && bi->bi_iter.bi_sector <= sector;
3280                      bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
3281                         if (bio_end_sector(bi) >= sector)
3282                                 sector = bio_end_sector(bi);
3283                 }
3284                 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
3285                         if (!test_and_set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags))
3286                                 sh->overwrite_disks++;
3287         }
3288
3289         pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
3290                 (unsigned long long)(*bip)->bi_iter.bi_sector,
3291                 (unsigned long long)sh->sector, dd_idx);
3292
3293         if (conf->mddev->bitmap && firstwrite) {
3294                 /* Cannot hold spinlock over bitmap_startwrite,
3295                  * but must ensure this isn't added to a batch until
3296                  * we have added to the bitmap and set bm_seq.
3297                  * So set STRIPE_BITMAP_PENDING to prevent
3298                  * batching.
3299                  * If multiple add_stripe_bio() calls race here they
3300                  * much all set STRIPE_BITMAP_PENDING.  So only the first one
3301                  * to complete "bitmap_startwrite" gets to set
3302                  * STRIPE_BIT_DELAY.  This is important as once a stripe
3303                  * is added to a batch, STRIPE_BIT_DELAY cannot be changed
3304                  * any more.
3305                  */
3306                 set_bit(STRIPE_BITMAP_PENDING, &sh->state);
3307                 spin_unlock_irq(&sh->stripe_lock);
3308                 md_bitmap_startwrite(conf->mddev->bitmap, sh->sector,
3309                                      STRIPE_SECTORS, 0);
3310                 spin_lock_irq(&sh->stripe_lock);
3311                 clear_bit(STRIPE_BITMAP_PENDING, &sh->state);
3312                 if (!sh->batch_head) {
3313                         sh->bm_seq = conf->seq_flush+1;
3314                         set_bit(STRIPE_BIT_DELAY, &sh->state);
3315                 }
3316         }
3317         spin_unlock_irq(&sh->stripe_lock);
3318
3319         if (stripe_can_batch(sh))
3320                 stripe_add_to_batch_list(conf, sh);
3321         return 1;
3322
3323  overlap:
3324         set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
3325         spin_unlock_irq(&sh->stripe_lock);
3326         return 0;
3327 }
3328
3329 static void end_reshape(struct r5conf *conf);
3330
3331 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
3332                             struct stripe_head *sh)
3333 {
3334         int sectors_per_chunk =
3335                 previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
3336         int dd_idx;
3337         int chunk_offset = sector_div(stripe, sectors_per_chunk);
3338         int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
3339
3340         raid5_compute_sector(conf,
3341                              stripe * (disks - conf->max_degraded)
3342                              *sectors_per_chunk + chunk_offset,
3343                              previous,
3344                              &dd_idx, sh);
3345 }
3346
3347 static void
3348 handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
3349                      struct stripe_head_state *s, int disks)
3350 {
3351         int i;
3352         BUG_ON(sh->batch_head);
3353         for (i = disks; i--; ) {
3354                 struct bio *bi;
3355                 int bitmap_end = 0;
3356
3357                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
3358                         struct md_rdev *rdev;
3359                         rcu_read_lock();
3360                         rdev = rcu_dereference(conf->disks[i].rdev);
3361                         if (rdev && test_bit(In_sync, &rdev->flags) &&
3362                             !test_bit(Faulty, &rdev->flags))
3363                                 atomic_inc(&rdev->nr_pending);
3364                         else
3365                                 rdev = NULL;
3366                         rcu_read_unlock();
3367                         if (rdev) {
3368                                 if (!rdev_set_badblocks(
3369                                             rdev,
3370                                             sh->sector,
3371                                             STRIPE_SECTORS, 0))
3372                                         md_error(conf->mddev, rdev);
3373                                 rdev_dec_pending(rdev, conf->mddev);
3374                         }
3375                 }
3376                 spin_lock_irq(&sh->stripe_lock);
3377                 /* fail all writes first */
3378                 bi = sh->dev[i].towrite;
3379                 sh->dev[i].towrite = NULL;
3380                 sh->overwrite_disks = 0;
3381                 spin_unlock_irq(&sh->stripe_lock);
3382                 if (bi)
3383                         bitmap_end = 1;
3384
3385                 log_stripe_write_finished(sh);
3386
3387                 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3388                         wake_up(&conf->wait_for_overlap);
3389
3390                 while (bi && bi->bi_iter.bi_sector <
3391                         sh->dev[i].sector + STRIPE_SECTORS) {
3392                         struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
3393
3394                         md_write_end(conf->mddev);
3395                         bio_io_error(bi);
3396                         bi = nextbi;
3397                 }
3398                 if (bitmap_end)
3399                         md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3400                                            STRIPE_SECTORS, 0, 0);
3401                 bitmap_end = 0;
3402                 /* and fail all 'written' */
3403                 bi = sh->dev[i].written;
3404                 sh->dev[i].written = NULL;
3405                 if (test_and_clear_bit(R5_SkipCopy, &sh->dev[i].flags)) {
3406                         WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
3407                         sh->dev[i].page = sh->dev[i].orig_page;
3408                 }
3409
3410                 if (bi) bitmap_end = 1;
3411                 while (bi && bi->bi_iter.bi_sector <
3412                        sh->dev[i].sector + STRIPE_SECTORS) {
3413                         struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
3414
3415                         md_write_end(conf->mddev);
3416                         bio_io_error(bi);
3417                         bi = bi2;
3418                 }
3419
3420                 /* fail any reads if this device is non-operational and
3421                  * the data has not reached the cache yet.
3422                  */
3423                 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
3424                     s->failed > conf->max_degraded &&
3425                     (!test_bit(R5_Insync, &sh->dev[i].flags) ||
3426                       test_bit(R5_ReadError, &sh->dev[i].flags))) {
3427                         spin_lock_irq(&sh->stripe_lock);
3428                         bi = sh->dev[i].toread;
3429                         sh->dev[i].toread = NULL;
3430                         spin_unlock_irq(&sh->stripe_lock);
3431                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3432                                 wake_up(&conf->wait_for_overlap);
3433                         if (bi)
3434                                 s->to_read--;
3435                         while (bi && bi->bi_iter.bi_sector <
3436                                sh->dev[i].sector + STRIPE_SECTORS) {
3437                                 struct bio *nextbi =
3438                                         r5_next_bio(bi, sh->dev[i].sector);
3439
3440                                 bio_io_error(bi);
3441                                 bi = nextbi;
3442                         }
3443                 }
3444                 if (bitmap_end)
3445                         md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3446                                            STRIPE_SECTORS, 0, 0);
3447                 /* If we were in the middle of a write the parity block might
3448                  * still be locked - so just clear all R5_LOCKED flags
3449                  */
3450                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
3451         }
3452         s->to_write = 0;
3453         s->written = 0;
3454
3455         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3456                 if (atomic_dec_and_test(&conf->pending_full_writes))
3457                         md_wakeup_thread(conf->mddev->thread);
3458 }
3459
3460 static void
3461 handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
3462                    struct stripe_head_state *s)
3463 {
3464         int abort = 0;
3465         int i;
3466
3467         BUG_ON(sh->batch_head);
3468         clear_bit(STRIPE_SYNCING, &sh->state);
3469         if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
3470                 wake_up(&conf->wait_for_overlap);
3471         s->syncing = 0;
3472         s->replacing = 0;
3473         /* There is nothing more to do for sync/check/repair.
3474          * Don't even need to abort as that is handled elsewhere
3475          * if needed, and not always wanted e.g. if there is a known
3476          * bad block here.
3477          * For recover/replace we need to record a bad block on all
3478          * non-sync devices, or abort the recovery
3479          */
3480         if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
3481                 /* During recovery devices cannot be removed, so
3482                  * locking and refcounting of rdevs is not needed
3483                  */
3484                 rcu_read_lock();
3485                 for (i = 0; i < conf->raid_disks; i++) {
3486                         struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
3487                         if (rdev
3488                             && !test_bit(Faulty, &rdev->flags)
3489                             && !test_bit(In_sync, &rdev->flags)
3490                             && !rdev_set_badblocks(rdev, sh->sector,
3491                                                    STRIPE_SECTORS, 0))
3492                                 abort = 1;
3493                         rdev = rcu_dereference(conf->disks[i].replacement);
3494                         if (rdev
3495                             && !test_bit(Faulty, &rdev->flags)
3496                             && !test_bit(In_sync, &rdev->flags)
3497                             && !rdev_set_badblocks(rdev, sh->sector,
3498                                                    STRIPE_SECTORS, 0))
3499                                 abort = 1;
3500                 }
3501                 rcu_read_unlock();
3502                 if (abort)
3503                         conf->recovery_disabled =
3504                                 conf->mddev->recovery_disabled;
3505         }
3506         md_done_sync(conf->mddev, STRIPE_SECTORS, !abort);
3507 }
3508
3509 static int want_replace(struct stripe_head *sh, int disk_idx)
3510 {
3511         struct md_rdev *rdev;
3512         int rv = 0;
3513
3514         rcu_read_lock();
3515         rdev = rcu_dereference(sh->raid_conf->disks[disk_idx].replacement);
3516         if (rdev
3517             && !test_bit(Faulty, &rdev->flags)
3518             && !test_bit(In_sync, &rdev->flags)
3519             && (rdev->recovery_offset <= sh->sector
3520                 || rdev->mddev->recovery_cp <= sh->sector))
3521                 rv = 1;
3522         rcu_read_unlock();
3523         return rv;
3524 }
3525
3526 static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
3527                            int disk_idx, int disks)
3528 {
3529         struct r5dev *dev = &sh->dev[disk_idx];
3530         struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
3531                                   &sh->dev[s->failed_num[1]] };
3532         int i;
3533
3534
3535         if (test_bit(R5_LOCKED, &dev->flags) ||
3536             test_bit(R5_UPTODATE, &dev->flags))
3537                 /* No point reading this as we already have it or have
3538                  * decided to get it.
3539                  */
3540                 return 0;
3541
3542         if (dev->toread ||
3543             (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)))
3544                 /* We need this block to directly satisfy a request */
3545                 return 1;
3546
3547         if (s->syncing || s->expanding ||
3548             (s->replacing && want_replace(sh, disk_idx)))
3549                 /* When syncing, or expanding we read everything.
3550                  * When replacing, we need the replaced block.
3551                  */
3552                 return 1;
3553
3554         if ((s->failed >= 1 && fdev[0]->toread) ||
3555             (s->failed >= 2 && fdev[1]->toread))
3556                 /* If we want to read from a failed device, then
3557                  * we need to actually read every other device.
3558                  */
3559                 return 1;
3560
3561         /* Sometimes neither read-modify-write nor reconstruct-write
3562          * cycles can work.  In those cases we read every block we
3563          * can.  Then the parity-update is certain to have enough to
3564          * work with.
3565          * This can only be a problem when we need to write something,
3566          * and some device has failed.  If either of those tests
3567          * fail we need look no further.
3568          */
3569         if (!s->failed || !s->to_write)
3570                 return 0;
3571
3572         if (test_bit(R5_Insync, &dev->flags) &&
3573             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3574                 /* Pre-reads at not permitted until after short delay
3575                  * to gather multiple requests.  However if this
3576                  * device is no Insync, the block could only be computed
3577                  * and there is no need to delay that.
3578                  */
3579                 return 0;
3580
3581         for (i = 0; i < s->failed && i < 2; i++) {
3582                 if (fdev[i]->towrite &&
3583                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3584                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3585                         /* If we have a partial write to a failed
3586                          * device, then we will need to reconstruct
3587                          * the content of that device, so all other
3588                          * devices must be read.
3589                          */
3590                         return 1;
3591         }
3592
3593         /* If we are forced to do a reconstruct-write, either because
3594          * the current RAID6 implementation only supports that, or
3595          * because parity cannot be trusted and we are currently
3596          * recovering it, there is extra need to be careful.
3597          * If one of the devices that we would need to read, because
3598          * it is not being overwritten (and maybe not written at all)
3599          * is missing/faulty, then we need to read everything we can.
3600          */
3601         if (sh->raid_conf->level != 6 &&
3602             sh->sector < sh->raid_conf->mddev->recovery_cp)
3603                 /* reconstruct-write isn't being forced */
3604                 return 0;
3605         for (i = 0; i < s->failed && i < 2; i++) {
3606                 if (s->failed_num[i] != sh->pd_idx &&
3607                     s->failed_num[i] != sh->qd_idx &&
3608                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3609                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3610                         return 1;
3611         }
3612
3613         return 0;
3614 }
3615
3616 /* fetch_block - checks the given member device to see if its data needs
3617  * to be read or computed to satisfy a request.
3618  *
3619  * Returns 1 when no more member devices need to be checked, otherwise returns
3620  * 0 to tell the loop in handle_stripe_fill to continue
3621  */
3622 static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
3623                        int disk_idx, int disks)
3624 {
3625         struct r5dev *dev = &sh->dev[disk_idx];
3626
3627         /* is the data in this block needed, and can we get it? */
3628         if (need_this_block(sh, s, disk_idx, disks)) {
3629                 /* we would like to get this block, possibly by computing it,
3630                  * otherwise read it if the backing disk is insync
3631                  */
3632                 BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
3633                 BUG_ON(test_bit(R5_Wantread, &dev->flags));
3634                 BUG_ON(sh->batch_head);
3635
3636                 /*
3637                  * In the raid6 case if the only non-uptodate disk is P
3638                  * then we already trusted P to compute the other failed
3639                  * drives. It is safe to compute rather than re-read P.
3640                  * In other cases we only compute blocks from failed
3641                  * devices, otherwise check/repair might fail to detect
3642                  * a real inconsistency.
3643                  */
3644
3645                 if ((s->uptodate == disks - 1) &&
3646                     ((sh->qd_idx >= 0 && sh->pd_idx == disk_idx) ||
3647                     (s->failed && (disk_idx == s->failed_num[0] ||
3648                                    disk_idx == s->failed_num[1])))) {
3649                         /* have disk failed, and we're requested to fetch it;
3650                          * do compute it
3651                          */
3652                         pr_debug("Computing stripe %llu block %d\n",
3653                                (unsigned long long)sh->sector, disk_idx);
3654                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3655                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3656                         set_bit(R5_Wantcompute, &dev->flags);
3657                         sh->ops.target = disk_idx;
3658                         sh->ops.target2 = -1; /* no 2nd target */
3659                         s->req_compute = 1;
3660                         /* Careful: from this point on 'uptodate' is in the eye
3661                          * of raid_run_ops which services 'compute' operations
3662                          * before writes. R5_Wantcompute flags a block that will
3663                          * be R5_UPTODATE by the time it is needed for a
3664                          * subsequent operation.
3665                          */
3666                         s->uptodate++;
3667                         return 1;
3668                 } else if (s->uptodate == disks-2 && s->failed >= 2) {
3669                         /* Computing 2-failure is *very* expensive; only
3670                          * do it if failed >= 2
3671                          */
3672                         int other;
3673                         for (other = disks; other--; ) {
3674                                 if (other == disk_idx)
3675                                         continue;
3676                                 if (!test_bit(R5_UPTODATE,
3677                                       &sh->dev[other].flags))
3678                                         break;
3679                         }
3680                         BUG_ON(other < 0);
3681                         pr_debug("Computing stripe %llu blocks %d,%d\n",
3682                                (unsigned long long)sh->sector,
3683                                disk_idx, other);
3684                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3685                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3686                         set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
3687                         set_bit(R5_Wantcompute, &sh->dev[other].flags);
3688                         sh->ops.target = disk_idx;
3689                         sh->ops.target2 = other;
3690                         s->uptodate += 2;
3691                         s->req_compute = 1;
3692                         return 1;
3693                 } else if (test_bit(R5_Insync, &dev->flags)) {
3694                         set_bit(R5_LOCKED, &dev->flags);
3695                         set_bit(R5_Wantread, &dev->flags);
3696                         s->locked++;
3697                         pr_debug("Reading block %d (sync=%d)\n",
3698                                 disk_idx, s->syncing);
3699                 }
3700         }
3701
3702         return 0;
3703 }
3704
3705 /**
3706  * handle_stripe_fill - read or compute data to satisfy pending requests.
3707  */
3708 static void handle_stripe_fill(struct stripe_head *sh,
3709                                struct stripe_head_state *s,
3710                                int disks)
3711 {
3712         int i;
3713
3714         /* look for blocks to read/compute, skip this if a compute
3715          * is already in flight, or if the stripe contents are in the
3716          * midst of changing due to a write
3717          */
3718         if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
3719             !sh->reconstruct_state) {
3720
3721                 /*
3722                  * For degraded stripe with data in journal, do not handle
3723                  * read requests yet, instead, flush the stripe to raid
3724                  * disks first, this avoids handling complex rmw of write
3725                  * back cache (prexor with orig_page, and then xor with
3726                  * page) in the read path
3727                  */
3728                 if (s->injournal && s->failed) {
3729                         if (test_bit(STRIPE_R5C_CACHING, &sh->state))
3730                                 r5c_make_stripe_write_out(sh);
3731                         goto out;
3732                 }
3733
3734                 for (i = disks; i--; )
3735                         if (fetch_block(sh, s, i, disks))
3736                                 break;
3737         }
3738 out:
3739         set_bit(STRIPE_HANDLE, &sh->state);
3740 }
3741
3742 static void break_stripe_batch_list(struct stripe_head *head_sh,
3743                                     unsigned long handle_flags);
3744 /* handle_stripe_clean_event
3745  * any written block on an uptodate or failed drive can be returned.
3746  * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
3747  * never LOCKED, so we don't need to test 'failed' directly.
3748  */
3749 static void handle_stripe_clean_event(struct r5conf *conf,
3750         struct stripe_head *sh, int disks)
3751 {
3752         int i;
3753         struct r5dev *dev;
3754         int discard_pending = 0;
3755         struct stripe_head *head_sh = sh;
3756         bool do_endio = false;
3757
3758         for (i = disks; i--; )
3759                 if (sh->dev[i].written) {
3760                         dev = &sh->dev[i];
3761                         if (!test_bit(R5_LOCKED, &dev->flags) &&
3762                             (test_bit(R5_UPTODATE, &dev->flags) ||
3763                              test_bit(R5_Discard, &dev->flags) ||
3764                              test_bit(R5_SkipCopy, &dev->flags))) {
3765                                 /* We can return any write requests */
3766                                 struct bio *wbi, *wbi2;
3767                                 pr_debug("Return write for disc %d\n", i);
3768                                 if (test_and_clear_bit(R5_Discard, &dev->flags))
3769                                         clear_bit(R5_UPTODATE, &dev->flags);
3770                                 if (test_and_clear_bit(R5_SkipCopy, &dev->flags)) {
3771                                         WARN_ON(test_bit(R5_UPTODATE, &dev->flags));
3772                                 }
3773                                 do_endio = true;
3774
3775 returnbi:
3776                                 dev->page = dev->orig_page;
3777                                 wbi = dev->written;
3778                                 dev->written = NULL;
3779                                 while (wbi && wbi->bi_iter.bi_sector <
3780                                         dev->sector + STRIPE_SECTORS) {
3781                                         wbi2 = r5_next_bio(wbi, dev->sector);
3782                                         md_write_end(conf->mddev);
3783                                         bio_endio(wbi);
3784                                         wbi = wbi2;
3785                                 }
3786                                 md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3787                                                    STRIPE_SECTORS,
3788                                                    !test_bit(STRIPE_DEGRADED, &sh->state),
3789                                                    0);
3790                                 if (head_sh->batch_head) {
3791                                         sh = list_first_entry(&sh->batch_list,
3792                                                               struct stripe_head,
3793                                                               batch_list);
3794                                         if (sh != head_sh) {
3795                                                 dev = &sh->dev[i];
3796                                                 goto returnbi;
3797                                         }
3798                                 }
3799                                 sh = head_sh;
3800                                 dev = &sh->dev[i];
3801                         } else if (test_bit(R5_Discard, &dev->flags))
3802                                 discard_pending = 1;
3803                 }
3804
3805         log_stripe_write_finished(sh);
3806
3807         if (!discard_pending &&
3808             test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) {
3809                 int hash;
3810                 clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
3811                 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
3812                 if (sh->qd_idx >= 0) {
3813                         clear_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
3814                         clear_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags);
3815                 }
3816                 /* now that discard is done we can proceed with any sync */
3817                 clear_bit(STRIPE_DISCARD, &sh->state);
3818                 /*
3819                  * SCSI discard will change some bio fields and the stripe has
3820                  * no updated data, so remove it from hash list and the stripe
3821                  * will be reinitialized
3822                  */
3823 unhash:
3824                 hash = sh->hash_lock_index;
3825                 spin_lock_irq(conf->hash_locks + hash);
3826                 remove_hash(sh);
3827                 spin_unlock_irq(conf->hash_locks + hash);
3828                 if (head_sh->batch_head) {
3829                         sh = list_first_entry(&sh->batch_list,
3830                                               struct stripe_head, batch_list);
3831                         if (sh != head_sh)
3832                                         goto unhash;
3833                 }
3834                 sh = head_sh;
3835
3836                 if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
3837                         set_bit(STRIPE_HANDLE, &sh->state);
3838
3839         }
3840
3841         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3842                 if (atomic_dec_and_test(&conf->pending_full_writes))
3843                         md_wakeup_thread(conf->mddev->thread);
3844
3845         if (head_sh->batch_head && do_endio)
3846                 break_stripe_batch_list(head_sh, STRIPE_EXPAND_SYNC_FLAGS);
3847 }
3848
3849 /*
3850  * For RMW in write back cache, we need extra page in prexor to store the
3851  * old data. This page is stored in dev->orig_page.
3852  *
3853  * This function checks whether we have data for prexor. The exact logic
3854  * is:
3855  *       R5_UPTODATE && (!R5_InJournal || R5_OrigPageUPTDODATE)
3856  */
3857 static inline bool uptodate_for_rmw(struct r5dev *dev)
3858 {
3859         return (test_bit(R5_UPTODATE, &dev->flags)) &&
3860                 (!test_bit(R5_InJournal, &dev->flags) ||
3861                  test_bit(R5_OrigPageUPTDODATE, &dev->flags));
3862 }
3863
3864 static int handle_stripe_dirtying(struct r5conf *conf,
3865                                   struct stripe_head *sh,
3866                                   struct stripe_head_state *s,
3867                                   int disks)
3868 {
3869         int rmw = 0, rcw = 0, i;
3870         sector_t recovery_cp = conf->mddev->recovery_cp;
3871
3872         /* Check whether resync is now happening or should start.
3873          * If yes, then the array is dirty (after unclean shutdown or
3874          * initial creation), so parity in some stripes might be inconsistent.
3875          * In this case, we need to always do reconstruct-write, to ensure
3876          * that in case of drive failure or read-error correction, we
3877          * generate correct data from the parity.
3878          */
3879         if (conf->rmw_level == PARITY_DISABLE_RMW ||
3880             (recovery_cp < MaxSector && sh->sector >= recovery_cp &&
3881              s->failed == 0)) {
3882                 /* Calculate the real rcw later - for now make it
3883                  * look like rcw is cheaper
3884                  */
3885                 rcw = 1; rmw = 2;
3886                 pr_debug("force RCW rmw_level=%u, recovery_cp=%llu sh->sector=%llu\n",
3887                          conf->rmw_level, (unsigned long long)recovery_cp,
3888                          (unsigned long long)sh->sector);
3889         } else for (i = disks; i--; ) {
3890                 /* would I have to read this buffer for read_modify_write */
3891                 struct r5dev *dev = &sh->dev[i];
3892                 if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3893                      i == sh->pd_idx || i == sh->qd_idx ||
3894                      test_bit(R5_InJournal, &dev->flags)) &&
3895                     !test_bit(R5_LOCKED, &dev->flags) &&
3896                     !(uptodate_for_rmw(dev) ||
3897                       test_bit(R5_Wantcompute, &dev->flags))) {
3898                         if (test_bit(R5_Insync, &dev->flags))
3899                                 rmw++;
3900                         else
3901                                 rmw += 2*disks;  /* cannot read it */
3902                 }
3903                 /* Would I have to read this buffer for reconstruct_write */
3904                 if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3905                     i != sh->pd_idx && i != sh->qd_idx &&
3906                     !test_bit(R5_LOCKED, &dev->flags) &&
3907                     !(test_bit(R5_UPTODATE, &dev->flags) ||
3908                       test_bit(R5_Wantcompute, &dev->flags))) {
3909                         if (test_bit(R5_Insync, &dev->flags))
3910                                 rcw++;
3911                         else
3912                                 rcw += 2*disks;
3913                 }
3914         }
3915
3916         pr_debug("for sector %llu state 0x%lx, rmw=%d rcw=%d\n",
3917                  (unsigned long long)sh->sector, sh->state, rmw, rcw);
3918         set_bit(STRIPE_HANDLE, &sh->state);
3919         if ((rmw < rcw || (rmw == rcw && conf->rmw_level == PARITY_PREFER_RMW)) && rmw > 0) {
3920                 /* prefer read-modify-write, but need to get some data */
3921                 if (conf->mddev->queue)
3922                         blk_add_trace_msg(conf->mddev->queue,
3923                                           "raid5 rmw %llu %d",
3924                                           (unsigned long long)sh->sector, rmw);
3925                 for (i = disks; i--; ) {
3926                         struct r5dev *dev = &sh->dev[i];
3927                         if (test_bit(R5_InJournal, &dev->flags) &&
3928                             dev->page == dev->orig_page &&
3929                             !test_bit(R5_LOCKED, &sh->dev[sh->pd_idx].flags)) {
3930                                 /* alloc page for prexor */
3931                                 struct page *p = alloc_page(GFP_NOIO);
3932
3933                                 if (p) {
3934                                         dev->orig_page = p;
3935                                         continue;
3936                                 }
3937
3938                                 /*
3939                                  * alloc_page() failed, try use
3940                                  * disk_info->extra_page
3941                                  */
3942                                 if (!test_and_set_bit(R5C_EXTRA_PAGE_IN_USE,
3943                                                       &conf->cache_state)) {
3944                                         r5c_use_extra_page(sh);
3945                                         break;
3946                                 }
3947
3948                                 /* extra_page in use, add to delayed_list */
3949                                 set_bit(STRIPE_DELAYED, &sh->state);
3950                                 s->waiting_extra_page = 1;
3951                                 return -EAGAIN;
3952                         }
3953                 }
3954
3955                 for (i = disks; i--; ) {
3956                         struct r5dev *dev = &sh->dev[i];
3957                         if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3958                              i == sh->pd_idx || i == sh->qd_idx ||
3959                              test_bit(R5_InJournal, &dev->flags)) &&
3960                             !test_bit(R5_LOCKED, &dev->flags) &&
3961                             !(uptodate_for_rmw(dev) ||
3962                               test_bit(R5_Wantcompute, &dev->flags)) &&
3963                             test_bit(R5_Insync, &dev->flags)) {
3964                                 if (test_bit(STRIPE_PREREAD_ACTIVE,
3965                                              &sh->state)) {
3966                                         pr_debug("Read_old block %d for r-m-w\n",
3967                                                  i);
3968                                         set_bit(R5_LOCKED, &dev->flags);
3969                                         set_bit(R5_Wantread, &dev->flags);
3970                                         s->locked++;
3971                                 } else {
3972                                         set_bit(STRIPE_DELAYED, &sh->state);
3973                                         set_bit(STRIPE_HANDLE, &sh->state);
3974                                 }
3975                         }
3976                 }
3977         }
3978         if ((rcw < rmw || (rcw == rmw && conf->rmw_level != PARITY_PREFER_RMW)) && rcw > 0) {
3979                 /* want reconstruct write, but need to get some data */
3980                 int qread =0;
3981                 rcw = 0;
3982                 for (i = disks; i--; ) {
3983                         struct r5dev *dev = &sh->dev[i];
3984                         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3985                             i != sh->pd_idx && i != sh->qd_idx &&
3986                             !test_bit(R5_LOCKED, &dev->flags) &&
3987                             !(test_bit(R5_UPTODATE, &dev->flags) ||
3988                               test_bit(R5_Wantcompute, &dev->flags))) {
3989                                 rcw++;
3990                                 if (test_bit(R5_Insync, &dev->flags) &&
3991                                     test_bit(STRIPE_PREREAD_ACTIVE,
3992                                              &sh->state)) {
3993                                         pr_debug("Read_old block "
3994                                                 "%d for Reconstruct\n", i);
3995                                         set_bit(R5_LOCKED, &dev->flags);
3996                                         set_bit(R5_Wantread, &dev->flags);
3997                                         s->locked++;
3998                                         qread++;
3999                                 } else {
4000                                         set_bit(STRIPE_DELAYED, &sh->state);
4001                                         set_bit(STRIPE_HANDLE, &sh->state);
4002                                 }
4003                         }
4004                 }
4005                 if (rcw && conf->mddev->queue)
4006                         blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
4007                                           (unsigned long long)sh->sector,
4008                                           rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
4009         }
4010
4011         if (rcw > disks && rmw > disks &&
4012             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4013                 set_bit(STRIPE_DELAYED, &sh->state);
4014
4015         /* now if nothing is locked, and if we have enough data,
4016          * we can start a write request
4017          */
4018         /* since handle_stripe can be called at any time we need to handle the
4019          * case where a compute block operation has been submitted and then a
4020          * subsequent call wants to start a write request.  raid_run_ops only
4021          * handles the case where compute block and reconstruct are requested
4022          * simultaneously.  If this is not the case then new writes need to be
4023          * held off until the compute completes.
4024          */
4025         if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
4026             (s->locked == 0 && (rcw == 0 || rmw == 0) &&
4027              !test_bit(STRIPE_BIT_DELAY, &sh->state)))
4028                 schedule_reconstruction(sh, s, rcw == 0, 0);
4029         return 0;
4030 }
4031
4032 static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
4033                                 struct stripe_head_state *s, int disks)
4034 {
4035         struct r5dev *dev = NULL;
4036
4037         BUG_ON(sh->batch_head);
4038         set_bit(STRIPE_HANDLE, &sh->state);
4039
4040         switch (sh->check_state) {
4041         case check_state_idle:
4042                 /* start a new check operation if there are no failures */
4043                 if (s->failed == 0) {
4044                         BUG_ON(s->uptodate != disks);
4045                         sh->check_state = check_state_run;
4046                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4047                         clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4048                         s->uptodate--;
4049                         break;
4050                 }
4051                 dev = &sh->dev[s->failed_num[0]];
4052                 /* fall through */
4053         case check_state_compute_result:
4054                 sh->check_state = check_state_idle;
4055                 if (!dev)
4056                         dev = &sh->dev[sh->pd_idx];
4057
4058                 /* check that a write has not made the stripe insync */
4059                 if (test_bit(STRIPE_INSYNC, &sh->state))
4060                         break;
4061
4062                 /* either failed parity check, or recovery is happening */
4063                 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
4064                 BUG_ON(s->uptodate != disks);
4065
4066                 set_bit(R5_LOCKED, &dev->flags);
4067                 s->locked++;
4068                 set_bit(R5_Wantwrite, &dev->flags);
4069
4070                 clear_bit(STRIPE_DEGRADED, &sh->state);
4071                 set_bit(STRIPE_INSYNC, &sh->state);
4072                 break;
4073         case check_state_run:
4074                 break; /* we will be called again upon completion */
4075         case check_state_check_result:
4076                 sh->check_state = check_state_idle;
4077
4078                 /* if a failure occurred during the check operation, leave
4079                  * STRIPE_INSYNC not set and let the stripe be handled again
4080                  */
4081                 if (s->failed)
4082                         break;
4083
4084                 /* handle a successful check operation, if parity is correct
4085                  * we are done.  Otherwise update the mismatch count and repair
4086                  * parity if !MD_RECOVERY_CHECK
4087                  */
4088                 if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
4089                         /* parity is correct (on disc,
4090                          * not in buffer any more)
4091                          */
4092                         set_bit(STRIPE_INSYNC, &sh->state);
4093                 else {
4094                         atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
4095                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4096                                 /* don't try to repair!! */
4097                                 set_bit(STRIPE_INSYNC, &sh->state);
4098                                 pr_warn_ratelimited("%s: mismatch sector in range "
4099                                                     "%llu-%llu\n", mdname(conf->mddev),
4100                                                     (unsigned long long) sh->sector,
4101                                                     (unsigned long long) sh->sector +
4102                                                     STRIPE_SECTORS);
4103                         } else {
4104                                 sh->check_state = check_state_compute_run;
4105                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4106                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4107                                 set_bit(R5_Wantcompute,
4108                                         &sh->dev[sh->pd_idx].flags);
4109                                 sh->ops.target = sh->pd_idx;
4110                                 sh->ops.target2 = -1;
4111                                 s->uptodate++;
4112                         }
4113                 }
4114                 break;
4115         case check_state_compute_run:
4116                 break;
4117         default:
4118                 pr_err("%s: unknown check_state: %d sector: %llu\n",
4119                        __func__, sh->check_state,
4120                        (unsigned long long) sh->sector);
4121                 BUG();
4122         }
4123 }
4124
4125 static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
4126                                   struct stripe_head_state *s,
4127                                   int disks)
4128 {
4129         int pd_idx = sh->pd_idx;
4130         int qd_idx = sh->qd_idx;
4131         struct r5dev *dev;
4132
4133         BUG_ON(sh->batch_head);
4134         set_bit(STRIPE_HANDLE, &sh->state);
4135
4136         BUG_ON(s->failed > 2);
4137
4138         /* Want to check and possibly repair P and Q.
4139          * However there could be one 'failed' device, in which
4140          * case we can only check one of them, possibly using the
4141          * other to generate missing data
4142          */
4143
4144         switch (sh->check_state) {
4145         case check_state_idle:
4146                 /* start a new check operation if there are < 2 failures */
4147                 if (s->failed == s->q_failed) {
4148                         /* The only possible failed device holds Q, so it
4149                          * makes sense to check P (If anything else were failed,
4150                          * we would have used P to recreate it).
4151                          */
4152                         sh->check_state = check_state_run;
4153                 }
4154                 if (!s->q_failed && s->failed < 2) {
4155                         /* Q is not failed, and we didn't use it to generate
4156                          * anything, so it makes sense to check it
4157                          */
4158                         if (sh->check_state == check_state_run)
4159                                 sh->check_state = check_state_run_pq;
4160                         else
4161                                 sh->check_state = check_state_run_q;
4162                 }
4163
4164                 /* discard potentially stale zero_sum_result */
4165                 sh->ops.zero_sum_result = 0;
4166
4167                 if (sh->check_state == check_state_run) {
4168                         /* async_xor_zero_sum destroys the contents of P */
4169                         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
4170                         s->uptodate--;
4171                 }
4172                 if (sh->check_state >= check_state_run &&
4173                     sh->check_state <= check_state_run_pq) {
4174                         /* async_syndrome_zero_sum preserves P and Q, so
4175                          * no need to mark them !uptodate here
4176                          */
4177                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4178                         break;
4179                 }
4180
4181                 /* we have 2-disk failure */
4182                 BUG_ON(s->failed != 2);
4183                 /* fall through */
4184         case check_state_compute_result:
4185                 sh->check_state = check_state_idle;
4186
4187                 /* check that a write has not made the stripe insync */
4188                 if (test_bit(STRIPE_INSYNC, &sh->state))
4189                         break;
4190
4191                 /* now write out any block on a failed drive,
4192                  * or P or Q if they were recomputed
4193                  */
4194                 dev = NULL;
4195                 if (s->failed == 2) {
4196                         dev = &sh->dev[s->failed_num[1]];
4197                         s->locked++;
4198                         set_bit(R5_LOCKED, &dev->flags);
4199                         set_bit(R5_Wantwrite, &dev->flags);
4200                 }
4201                 if (s->failed >= 1) {
4202                         dev = &sh->dev[s->failed_num[0]];
4203                         s->locked++;
4204                         set_bit(R5_LOCKED, &dev->flags);
4205                         set_bit(R5_Wantwrite, &dev->flags);
4206                 }
4207                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4208                         dev = &sh->dev[pd_idx];
4209                         s->locked++;
4210                         set_bit(R5_LOCKED, &dev->flags);
4211                         set_bit(R5_Wantwrite, &dev->flags);
4212                 }
4213                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4214                         dev = &sh->dev[qd_idx];
4215                         s->locked++;
4216                         set_bit(R5_LOCKED, &dev->flags);
4217                         set_bit(R5_Wantwrite, &dev->flags);
4218                 }
4219                 if (WARN_ONCE(dev && !test_bit(R5_UPTODATE, &dev->flags),
4220                               "%s: disk%td not up to date\n",
4221                               mdname(conf->mddev),
4222                               dev - (struct r5dev *) &sh->dev)) {
4223                         clear_bit(R5_LOCKED, &dev->flags);
4224                         clear_bit(R5_Wantwrite, &dev->flags);
4225                         s->locked--;
4226                 }
4227                 clear_bit(STRIPE_DEGRADED, &sh->state);
4228
4229                 set_bit(STRIPE_INSYNC, &sh->state);
4230                 break;
4231         case check_state_run:
4232         case check_state_run_q:
4233         case check_state_run_pq:
4234                 break; /* we will be called again upon completion */
4235         case check_state_check_result:
4236                 sh->check_state = check_state_idle;
4237
4238                 /* handle a successful check operation, if parity is correct
4239                  * we are done.  Otherwise update the mismatch count and repair
4240                  * parity if !MD_RECOVERY_CHECK
4241                  */
4242                 if (sh->ops.zero_sum_result == 0) {
4243                         /* both parities are correct */
4244                         if (!s->failed)
4245                                 set_bit(STRIPE_INSYNC, &sh->state);
4246                         else {
4247                                 /* in contrast to the raid5 case we can validate
4248                                  * parity, but still have a failure to write
4249                                  * back
4250                                  */
4251                                 sh->check_state = check_state_compute_result;
4252                                 /* Returning at this point means that we may go
4253                                  * off and bring p and/or q uptodate again so
4254                                  * we make sure to check zero_sum_result again
4255                                  * to verify if p or q need writeback
4256                                  */
4257                         }
4258                 } else {
4259                         atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
4260                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4261                                 /* don't try to repair!! */
4262                                 set_bit(STRIPE_INSYNC, &sh->state);
4263                                 pr_warn_ratelimited("%s: mismatch sector in range "
4264                                                     "%llu-%llu\n", mdname(conf->mddev),
4265                                                     (unsigned long long) sh->sector,
4266                                                     (unsigned long long) sh->sector +
4267                                                     STRIPE_SECTORS);
4268                         } else {
4269                                 int *target = &sh->ops.target;
4270
4271                                 sh->ops.target = -1;
4272                                 sh->ops.target2 = -1;
4273                                 sh->check_state = check_state_compute_run;
4274                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4275                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4276                                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4277                                         set_bit(R5_Wantcompute,
4278                                                 &sh->dev[pd_idx].flags);
4279                                         *target = pd_idx;
4280                                         target = &sh->ops.target2;
4281                                         s->uptodate++;
4282                                 }
4283                                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4284                                         set_bit(R5_Wantcompute,
4285                                                 &sh->dev[qd_idx].flags);
4286                                         *target = qd_idx;
4287                                         s->uptodate++;
4288                                 }
4289                         }
4290                 }
4291                 break;
4292         case check_state_compute_run:
4293                 break;
4294         default:
4295                 pr_warn("%s: unknown check_state: %d sector: %llu\n",
4296                         __func__, sh->check_state,
4297                         (unsigned long long) sh->sector);
4298                 BUG();
4299         }
4300 }
4301
4302 static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
4303 {
4304         int i;
4305
4306         /* We have read all the blocks in this stripe and now we need to
4307          * copy some of them into a target stripe for expand.
4308          */
4309         struct dma_async_tx_descriptor *tx = NULL;
4310         BUG_ON(sh->batch_head);
4311         clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
4312         for (i = 0; i < sh->disks; i++)
4313                 if (i != sh->pd_idx && i != sh->qd_idx) {
4314                         int dd_idx, j;
4315                         struct stripe_head *sh2;
4316                         struct async_submit_ctl submit;
4317
4318                         sector_t bn = raid5_compute_blocknr(sh, i, 1);
4319                         sector_t s = raid5_compute_sector(conf, bn, 0,
4320                                                           &dd_idx, NULL);
4321                         sh2 = raid5_get_active_stripe(conf, s, 0, 1, 1);
4322                         if (sh2 == NULL)
4323                                 /* so far only the early blocks of this stripe
4324                                  * have been requested.  When later blocks
4325                                  * get requested, we will try again
4326                                  */
4327                                 continue;
4328                         if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
4329                            test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
4330                                 /* must have already done this block */
4331                                 raid5_release_stripe(sh2);
4332                                 continue;
4333                         }
4334
4335                         /* place all the copies on one channel */
4336                         init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
4337                         tx = async_memcpy(sh2->dev[dd_idx].page,
4338                                           sh->dev[i].page, 0, 0, STRIPE_SIZE,
4339                                           &submit);
4340
4341                         set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
4342                         set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
4343                         for (j = 0; j < conf->raid_disks; j++)
4344                                 if (j != sh2->pd_idx &&
4345                                     j != sh2->qd_idx &&
4346                                     !test_bit(R5_Expanded, &sh2->dev[j].flags))
4347                                         break;
4348                         if (j == conf->raid_disks) {
4349                                 set_bit(STRIPE_EXPAND_READY, &sh2->state);
4350                                 set_bit(STRIPE_HANDLE, &sh2->state);
4351                         }
4352                         raid5_release_stripe(sh2);
4353
4354                 }
4355         /* done submitting copies, wait for them to complete */
4356         async_tx_quiesce(&tx);
4357 }
4358
4359 /*
4360  * handle_stripe - do things to a stripe.
4361  *
4362  * We lock the stripe by setting STRIPE_ACTIVE and then examine the
4363  * state of various bits to see what needs to be done.
4364  * Possible results:
4365  *    return some read requests which now have data
4366  *    return some write requests which are safely on storage
4367  *    schedule a read on some buffers
4368  *    schedule a write of some buffers
4369  *    return confirmation of parity correctness
4370  *
4371  */
4372
4373 static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
4374 {
4375         struct r5conf *conf = sh->raid_conf;
4376         int disks = sh->disks;
4377         struct r5dev *dev;
4378         int i;
4379         int do_recovery = 0;
4380
4381         memset(s, 0, sizeof(*s));
4382
4383         s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state) && !sh->batch_head;
4384         s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state) && !sh->batch_head;
4385         s->failed_num[0] = -1;
4386         s->failed_num[1] = -1;
4387         s->log_failed = r5l_log_disk_error(conf);
4388
4389         /* Now to look around and see what can be done */
4390         rcu_read_lock();
4391         for (i=disks; i--; ) {
4392                 struct md_rdev *rdev;
4393                 sector_t first_bad;
4394                 int bad_sectors;
4395                 int is_bad = 0;
4396
4397                 dev = &sh->dev[i];
4398
4399                 pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
4400                          i, dev->flags,
4401                          dev->toread, dev->towrite, dev->written);
4402                 /* maybe we can reply to a read
4403                  *
4404                  * new wantfill requests are only permitted while
4405                  * ops_complete_biofill is guaranteed to be inactive
4406                  */
4407                 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
4408                     !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
4409                         set_bit(R5_Wantfill, &dev->flags);
4410
4411                 /* now count some things */
4412                 if (test_bit(R5_LOCKED, &dev->flags))
4413                         s->locked++;
4414                 if (test_bit(R5_UPTODATE, &dev->flags))
4415                         s->uptodate++;
4416                 if (test_bit(R5_Wantcompute, &dev->flags)) {
4417                         s->compute++;
4418                         BUG_ON(s->compute > 2);
4419                 }
4420
4421                 if (test_bit(R5_Wantfill, &dev->flags))
4422                         s->to_fill++;
4423                 else if (dev->toread)
4424                         s->to_read++;
4425                 if (dev->towrite) {
4426                         s->to_write++;
4427                         if (!test_bit(R5_OVERWRITE, &dev->flags))
4428                                 s->non_overwrite++;
4429                 }
4430                 if (dev->written)
4431                         s->written++;
4432                 /* Prefer to use the replacement for reads, but only
4433                  * if it is recovered enough and has no bad blocks.
4434                  */
4435                 rdev = rcu_dereference(conf->disks[i].replacement);
4436                 if (rdev && !test_bit(Faulty, &rdev->flags) &&
4437                     rdev->recovery_offset >= sh->sector + STRIPE_SECTORS &&
4438                     !is_badblock(rdev, sh->sector, STRIPE_SECTORS,
4439                                  &first_bad, &bad_sectors))
4440                         set_bit(R5_ReadRepl, &dev->flags);
4441                 else {
4442                         if (rdev && !test_bit(Faulty, &rdev->flags))
4443                                 set_bit(R5_NeedReplace, &dev->flags);
4444                         else
4445                                 clear_bit(R5_NeedReplace, &dev->flags);
4446                         rdev = rcu_dereference(conf->disks[i].rdev);
4447                         clear_bit(R5_ReadRepl, &dev->flags);
4448                 }
4449                 if (rdev && test_bit(Faulty, &rdev->flags))
4450                         rdev = NULL;
4451                 if (rdev) {
4452                         is_bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
4453                                              &first_bad, &bad_sectors);
4454                         if (s->blocked_rdev == NULL
4455                             && (test_bit(Blocked, &rdev->flags)
4456                                 || is_bad < 0)) {
4457                                 if (is_bad < 0)
4458                                         set_bit(BlockedBadBlocks,
4459                                                 &rdev->flags);
4460                                 s->blocked_rdev = rdev;
4461                                 atomic_inc(&rdev->nr_pending);
4462                         }
4463                 }
4464                 clear_bit(R5_Insync, &dev->flags);
4465                 if (!rdev)
4466                         /* Not in-sync */;
4467                 else if (is_bad) {
4468                         /* also not in-sync */
4469                         if (!test_bit(WriteErrorSeen, &rdev->flags) &&
4470                             test_bit(R5_UPTODATE, &dev->flags)) {
4471                                 /* treat as in-sync, but with a read error
4472                                  * which we can now try to correct
4473                                  */
4474                                 set_bit(R5_Insync, &dev->flags);
4475                                 set_bit(R5_ReadError, &dev->flags);
4476                         }
4477                 } else if (test_bit(In_sync, &rdev->flags))
4478                         set_bit(R5_Insync, &dev->flags);
4479                 else if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
4480                         /* in sync if before recovery_offset */
4481                         set_bit(R5_Insync, &dev->flags);
4482                 else if (test_bit(R5_UPTODATE, &dev->flags) &&
4483                          test_bit(R5_Expanded, &dev->flags))
4484                         /* If we've reshaped into here, we assume it is Insync.
4485                          * We will shortly update recovery_offset to make
4486                          * it official.
4487                          */
4488                         set_bit(R5_Insync, &dev->flags);
4489
4490                 if (test_bit(R5_WriteError, &dev->flags)) {
4491                         /* This flag does not apply to '.replacement'
4492                          * only to .rdev, so make sure to check that*/
4493                         struct md_rdev *rdev2 = rcu_dereference(
4494                                 conf->disks[i].rdev);
4495                         if (rdev2 == rdev)
4496                                 clear_bit(R5_Insync, &dev->flags);
4497                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4498                                 s->handle_bad_blocks = 1;
4499                                 atomic_inc(&rdev2->nr_pending);
4500                         } else
4501                                 clear_bit(R5_WriteError, &dev->flags);
4502                 }
4503                 if (test_bit(R5_MadeGood, &dev->flags)) {
4504                         /* This flag does not apply to '.replacement'
4505                          * only to .rdev, so make sure to check that*/
4506                         struct md_rdev *rdev2 = rcu_dereference(
4507                                 conf->disks[i].rdev);
4508                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4509                                 s->handle_bad_blocks = 1;
4510                                 atomic_inc(&rdev2->nr_pending);
4511                         } else
4512                                 clear_bit(R5_MadeGood, &dev->flags);
4513                 }
4514                 if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
4515                         struct md_rdev *rdev2 = rcu_dereference(
4516                                 conf->disks[i].replacement);
4517                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4518                                 s->handle_bad_blocks = 1;
4519                                 atomic_inc(&rdev2->nr_pending);
4520                         } else
4521                                 clear_bit(R5_MadeGoodRepl, &dev->flags);
4522                 }
4523                 if (!test_bit(R5_Insync, &dev->flags)) {
4524                         /* The ReadError flag will just be confusing now */
4525                         clear_bit(R5_ReadError, &dev->flags);
4526                         clear_bit(R5_ReWrite, &dev->flags);
4527                 }
4528                 if (test_bit(R5_ReadError, &dev->flags))
4529                         clear_bit(R5_Insync, &dev->flags);
4530                 if (!test_bit(R5_Insync, &dev->flags)) {
4531                         if (s->failed < 2)
4532                                 s->failed_num[s->failed] = i;
4533                         s->failed++;
4534                         if (rdev && !test_bit(Faulty, &rdev->flags))
4535                                 do_recovery = 1;
4536                         else if (!rdev) {
4537                                 rdev = rcu_dereference(
4538                                     conf->disks[i].replacement);
4539                                 if (rdev && !test_bit(Faulty, &rdev->flags))
4540                                         do_recovery = 1;
4541                         }
4542                 }
4543
4544                 if (test_bit(R5_InJournal, &dev->flags))
4545                         s->injournal++;
4546                 if (test_bit(R5_InJournal, &dev->flags) && dev->written)
4547                         s->just_cached++;
4548         }
4549         if (test_bit(STRIPE_SYNCING, &sh->state)) {
4550                 /* If there is a failed device being replaced,
4551                  *     we must be recovering.
4552                  * else if we are after recovery_cp, we must be syncing
4553                  * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
4554                  * else we can only be replacing
4555                  * sync and recovery both need to read all devices, and so
4556                  * use the same flag.
4557                  */
4558                 if (do_recovery ||
4559                     sh->sector >= conf->mddev->recovery_cp ||
4560                     test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
4561                         s->syncing = 1;
4562                 else
4563                         s->replacing = 1;
4564         }
4565         rcu_read_unlock();
4566 }
4567
4568 static int clear_batch_ready(struct stripe_head *sh)
4569 {
4570         /* Return '1' if this is a member of batch, or
4571          * '0' if it is a lone stripe or a head which can now be
4572          * handled.
4573          */
4574         struct stripe_head *tmp;
4575         if (!test_and_clear_bit(STRIPE_BATCH_READY, &sh->state))
4576                 return (sh->batch_head && sh->batch_head != sh);
4577         spin_lock(&sh->stripe_lock);
4578         if (!sh->batch_head) {
4579                 spin_unlock(&sh->stripe_lock);
4580                 return 0;
4581         }
4582
4583         /*
4584          * this stripe could be added to a batch list before we check
4585          * BATCH_READY, skips it
4586          */
4587         if (sh->batch_head != sh) {
4588                 spin_unlock(&sh->stripe_lock);
4589                 return 1;
4590         }
4591         spin_lock(&sh->batch_lock);
4592         list_for_each_entry(tmp, &sh->batch_list, batch_list)
4593                 clear_bit(STRIPE_BATCH_READY, &tmp->state);
4594         spin_unlock(&sh->batch_lock);
4595         spin_unlock(&sh->stripe_lock);
4596
4597         /*
4598          * BATCH_READY is cleared, no new stripes can be added.
4599          * batch_list can be accessed without lock
4600          */
4601         return 0;
4602 }
4603
4604 static void break_stripe_batch_list(struct stripe_head *head_sh,
4605                                     unsigned long handle_flags)
4606 {
4607         struct stripe_head *sh, *next;
4608         int i;
4609         int do_wakeup = 0;
4610
4611         list_for_each_entry_safe(sh, next, &head_sh->batch_list, batch_list) {
4612
4613                 list_del_init(&sh->batch_list);
4614
4615                 WARN_ONCE(sh->state & ((1 << STRIPE_ACTIVE) |
4616                                           (1 << STRIPE_SYNCING) |
4617                                           (1 << STRIPE_REPLACED) |
4618                                           (1 << STRIPE_DELAYED) |
4619                                           (1 << STRIPE_BIT_DELAY) |
4620                                           (1 << STRIPE_FULL_WRITE) |
4621                                           (1 << STRIPE_BIOFILL_RUN) |
4622                                           (1 << STRIPE_COMPUTE_RUN)  |
4623                                           (1 << STRIPE_OPS_REQ_PENDING) |
4624                                           (1 << STRIPE_DISCARD) |
4625                                           (1 << STRIPE_BATCH_READY) |
4626                                           (1 << STRIPE_BATCH_ERR) |
4627                                           (1 << STRIPE_BITMAP_PENDING)),
4628                         "stripe state: %lx\n", sh->state);
4629                 WARN_ONCE(head_sh->state & ((1 << STRIPE_DISCARD) |
4630                                               (1 << STRIPE_REPLACED)),
4631                         "head stripe state: %lx\n", head_sh->state);
4632
4633                 set_mask_bits(&sh->state, ~(STRIPE_EXPAND_SYNC_FLAGS |
4634                                             (1 << STRIPE_PREREAD_ACTIVE) |
4635                                             (1 << STRIPE_DEGRADED) |
4636                                             (1 << STRIPE_ON_UNPLUG_LIST)),
4637                               head_sh->state & (1 << STRIPE_INSYNC));
4638
4639                 sh->check_state = head_sh->check_state;
4640                 sh->reconstruct_state = head_sh->reconstruct_state;
4641                 spin_lock_irq(&sh->stripe_lock);
4642                 sh->batch_head = NULL;
4643                 spin_unlock_irq(&sh->stripe_lock);
4644                 for (i = 0; i < sh->disks; i++) {
4645                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
4646                                 do_wakeup = 1;
4647                         sh->dev[i].flags = head_sh->dev[i].flags &
4648                                 (~((1 << R5_WriteError) | (1 << R5_Overlap)));
4649                 }
4650                 if (handle_flags == 0 ||
4651                     sh->state & handle_flags)
4652                         set_bit(STRIPE_HANDLE, &sh->state);
4653                 raid5_release_stripe(sh);
4654         }
4655         spin_lock_irq(&head_sh->stripe_lock);
4656         head_sh->batch_head = NULL;
4657         spin_unlock_irq(&head_sh->stripe_lock);
4658         for (i = 0; i < head_sh->disks; i++)
4659                 if (test_and_clear_bit(R5_Overlap, &head_sh->dev[i].flags))
4660                         do_wakeup = 1;
4661         if (head_sh->state & handle_flags)
4662                 set_bit(STRIPE_HANDLE, &head_sh->state);
4663
4664         if (do_wakeup)
4665                 wake_up(&head_sh->raid_conf->wait_for_overlap);
4666 }
4667
4668 static void handle_stripe(struct stripe_head *sh)
4669 {
4670         struct stripe_head_state s;
4671         struct r5conf *conf = sh->raid_conf;
4672         int i;
4673         int prexor;
4674         int disks = sh->disks;
4675         struct r5dev *pdev, *qdev;
4676
4677         clear_bit(STRIPE_HANDLE, &sh->state);
4678         if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
4679                 /* already being handled, ensure it gets handled
4680                  * again when current action finishes */
4681                 set_bit(STRIPE_HANDLE, &sh->state);
4682                 return;
4683         }
4684
4685         if (clear_batch_ready(sh) ) {
4686                 clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
4687                 return;
4688         }
4689
4690         if (test_and_clear_bit(STRIPE_BATCH_ERR, &sh->state))
4691                 break_stripe_batch_list(sh, 0);
4692
4693         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) && !sh->batch_head) {
4694                 spin_lock(&sh->stripe_lock);
4695                 /*
4696                  * Cannot process 'sync' concurrently with 'discard'.
4697                  * Flush data in r5cache before 'sync'.
4698                  */
4699                 if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) &&
4700                     !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) &&
4701                     !test_bit(STRIPE_DISCARD, &sh->state) &&
4702                     test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
4703                         set_bit(STRIPE_SYNCING, &sh->state);
4704                         clear_bit(STRIPE_INSYNC, &sh->state);
4705                         clear_bit(STRIPE_REPLACED, &sh->state);
4706                 }
4707                 spin_unlock(&sh->stripe_lock);
4708         }
4709         clear_bit(STRIPE_DELAYED, &sh->state);
4710
4711         pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
4712                 "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
4713                (unsigned long long)sh->sector, sh->state,
4714                atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
4715                sh->check_state, sh->reconstruct_state);
4716
4717         analyse_stripe(sh, &s);
4718
4719         if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
4720                 goto finish;
4721
4722         if (s.handle_bad_blocks ||
4723             test_bit(MD_SB_CHANGE_PENDING, &conf->mddev->sb_flags)) {
4724                 set_bit(STRIPE_HANDLE, &sh->state);
4725                 goto finish;
4726         }
4727
4728         if (unlikely(s.blocked_rdev)) {
4729                 if (s.syncing || s.expanding || s.expanded ||
4730                     s.replacing || s.to_write || s.written) {
4731                         set_bit(STRIPE_HANDLE, &sh->state);
4732                         goto finish;
4733                 }
4734                 /* There is nothing for the blocked_rdev to block */
4735                 rdev_dec_pending(s.blocked_rdev, conf->mddev);
4736                 s.blocked_rdev = NULL;
4737         }
4738
4739         if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
4740                 set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
4741                 set_bit(STRIPE_BIOFILL_RUN, &sh->state);
4742         }
4743
4744         pr_debug("locked=%d uptodate=%d to_read=%d"
4745                " to_write=%d failed=%d failed_num=%d,%d\n",
4746                s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
4747                s.failed_num[0], s.failed_num[1]);
4748         /*
4749          * check if the array has lost more than max_degraded devices and,
4750          * if so, some requests might need to be failed.
4751          *
4752          * When journal device failed (log_failed), we will only process
4753          * the stripe if there is data need write to raid disks
4754          */
4755         if (s.failed > conf->max_degraded ||
4756             (s.log_failed && s.injournal == 0)) {
4757                 sh->check_state = 0;
4758                 sh->reconstruct_state = 0;
4759                 break_stripe_batch_list(sh, 0);
4760                 if (s.to_read+s.to_write+s.written)
4761                         handle_failed_stripe(conf, sh, &s, disks);
4762                 if (s.syncing + s.replacing)
4763                         handle_failed_sync(conf, sh, &s);
4764         }
4765
4766         /* Now we check to see if any write operations have recently
4767          * completed
4768          */
4769         prexor = 0;
4770         if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
4771                 prexor = 1;
4772         if (sh->reconstruct_state == reconstruct_state_drain_result ||
4773             sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
4774                 sh->reconstruct_state = reconstruct_state_idle;
4775
4776                 /* All the 'written' buffers and the parity block are ready to
4777                  * be written back to disk
4778                  */
4779                 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
4780                        !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
4781                 BUG_ON(sh->qd_idx >= 0 &&
4782                        !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
4783                        !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
4784                 for (i = disks; i--; ) {
4785                         struct r5dev *dev = &sh->dev[i];
4786                         if (test_bit(R5_LOCKED, &dev->flags) &&
4787                                 (i == sh->pd_idx || i == sh->qd_idx ||
4788                                  dev->written || test_bit(R5_InJournal,
4789                                                           &dev->flags))) {
4790                                 pr_debug("Writing block %d\n", i);
4791                                 set_bit(R5_Wantwrite, &dev->flags);
4792                                 if (prexor)
4793                                         continue;
4794                                 if (s.failed > 1)
4795                                         continue;
4796                                 if (!test_bit(R5_Insync, &dev->flags) ||
4797                                     ((i == sh->pd_idx || i == sh->qd_idx)  &&
4798                                      s.failed == 0))
4799                                         set_bit(STRIPE_INSYNC, &sh->state);
4800                         }
4801                 }
4802                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4803                         s.dec_preread_active = 1;
4804         }
4805
4806         /*
4807          * might be able to return some write requests if the parity blocks
4808          * are safe, or on a failed drive
4809          */
4810         pdev = &sh->dev[sh->pd_idx];
4811         s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
4812                 || (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
4813         qdev = &sh->dev[sh->qd_idx];
4814         s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
4815                 || (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
4816                 || conf->level < 6;
4817
4818         if (s.written &&
4819             (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
4820                              && !test_bit(R5_LOCKED, &pdev->flags)
4821                              && (test_bit(R5_UPTODATE, &pdev->flags) ||
4822                                  test_bit(R5_Discard, &pdev->flags))))) &&
4823             (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
4824                              && !test_bit(R5_LOCKED, &qdev->flags)
4825                              && (test_bit(R5_UPTODATE, &qdev->flags) ||
4826                                  test_bit(R5_Discard, &qdev->flags))))))
4827                 handle_stripe_clean_event(conf, sh, disks);
4828
4829         if (s.just_cached)
4830                 r5c_handle_cached_data_endio(conf, sh, disks);
4831         log_stripe_write_finished(sh);
4832
4833         /* Now we might consider reading some blocks, either to check/generate
4834          * parity, or to satisfy requests
4835          * or to load a block that is being partially written.
4836          */
4837         if (s.to_read || s.non_overwrite
4838             || (conf->level == 6 && s.to_write && s.failed)
4839             || (s.syncing && (s.uptodate + s.compute < disks))
4840             || s.replacing
4841             || s.expanding)
4842                 handle_stripe_fill(sh, &s, disks);
4843
4844         /*
4845          * When the stripe finishes full journal write cycle (write to journal
4846          * and raid disk), this is the clean up procedure so it is ready for
4847          * next operation.
4848          */
4849         r5c_finish_stripe_write_out(conf, sh, &s);
4850
4851         /*
4852          * Now to consider new write requests, cache write back and what else,
4853          * if anything should be read.  We do not handle new writes when:
4854          * 1/ A 'write' operation (copy+xor) is already in flight.
4855          * 2/ A 'check' operation is in flight, as it may clobber the parity
4856          *    block.
4857          * 3/ A r5c cache log write is in flight.
4858          */
4859
4860         if (!sh->reconstruct_state && !sh->check_state && !sh->log_io) {
4861                 if (!r5c_is_writeback(conf->log)) {
4862                         if (s.to_write)
4863                                 handle_stripe_dirtying(conf, sh, &s, disks);
4864                 } else { /* write back cache */
4865                         int ret = 0;
4866
4867                         /* First, try handle writes in caching phase */
4868                         if (s.to_write)
4869                                 ret = r5c_try_caching_write(conf, sh, &s,
4870                                                             disks);
4871                         /*
4872                          * If caching phase failed: ret == -EAGAIN
4873                          *    OR
4874                          * stripe under reclaim: !caching && injournal
4875                          *
4876                          * fall back to handle_stripe_dirtying()
4877                          */
4878                         if (ret == -EAGAIN ||
4879                             /* stripe under reclaim: !caching && injournal */
4880                             (!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
4881                              s.injournal > 0)) {
4882                                 ret = handle_stripe_dirtying(conf, sh, &s,
4883                                                              disks);
4884                                 if (ret == -EAGAIN)
4885                                         goto finish;
4886                         }
4887                 }
4888         }
4889
4890         /* maybe we need to check and possibly fix the parity for this stripe
4891          * Any reads will already have been scheduled, so we just see if enough
4892          * data is available.  The parity check is held off while parity
4893          * dependent operations are in flight.
4894          */
4895         if (sh->check_state ||
4896             (s.syncing && s.locked == 0 &&
4897              !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4898              !test_bit(STRIPE_INSYNC, &sh->state))) {
4899                 if (conf->level == 6)
4900                         handle_parity_checks6(conf, sh, &s, disks);
4901                 else
4902                         handle_parity_checks5(conf, sh, &s, disks);
4903         }
4904
4905         if ((s.replacing || s.syncing) && s.locked == 0
4906             && !test_bit(STRIPE_COMPUTE_RUN, &sh->state)
4907             && !test_bit(STRIPE_REPLACED, &sh->state)) {
4908                 /* Write out to replacement devices where possible */
4909                 for (i = 0; i < conf->raid_disks; i++)
4910                         if (test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
4911                                 WARN_ON(!test_bit(R5_UPTODATE, &sh->dev[i].flags));
4912                                 set_bit(R5_WantReplace, &sh->dev[i].flags);
4913                                 set_bit(R5_LOCKED, &sh->dev[i].flags);
4914                                 s.locked++;
4915                         }
4916                 if (s.replacing)
4917                         set_bit(STRIPE_INSYNC, &sh->state);
4918                 set_bit(STRIPE_REPLACED, &sh->state);
4919         }
4920         if ((s.syncing || s.replacing) && s.locked == 0 &&
4921             !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4922             test_bit(STRIPE_INSYNC, &sh->state)) {
4923                 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
4924                 clear_bit(STRIPE_SYNCING, &sh->state);
4925                 if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
4926                         wake_up(&conf->wait_for_overlap);
4927         }
4928
4929         /* If the failed drives are just a ReadError, then we might need
4930          * to progress the repair/check process
4931          */
4932         if (s.failed <= conf->max_degraded && !conf->mddev->ro)
4933                 for (i = 0; i < s.failed; i++) {
4934                         struct r5dev *dev = &sh->dev[s.failed_num[i]];
4935                         if (test_bit(R5_ReadError, &dev->flags)
4936                             && !test_bit(R5_LOCKED, &dev->flags)
4937                             && test_bit(R5_UPTODATE, &dev->flags)
4938                                 ) {
4939                                 if (!test_bit(R5_ReWrite, &dev->flags)) {
4940                                         set_bit(R5_Wantwrite, &dev->flags);
4941                                         set_bit(R5_ReWrite, &dev->flags);
4942                                         set_bit(R5_LOCKED, &dev->flags);
4943                                         s.locked++;
4944                                 } else {
4945                                         /* let's read it back */
4946                                         set_bit(R5_Wantread, &dev->flags);
4947                                         set_bit(R5_LOCKED, &dev->flags);
4948                                         s.locked++;
4949                                 }
4950                         }
4951                 }
4952
4953         /* Finish reconstruct operations initiated by the expansion process */
4954         if (sh->reconstruct_state == reconstruct_state_result) {
4955                 struct stripe_head *sh_src
4956                         = raid5_get_active_stripe(conf, sh->sector, 1, 1, 1);
4957                 if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
4958                         /* sh cannot be written until sh_src has been read.
4959                          * so arrange for sh to be delayed a little
4960                          */
4961                         set_bit(STRIPE_DELAYED, &sh->state);
4962                         set_bit(STRIPE_HANDLE, &sh->state);
4963                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
4964                                               &sh_src->state))
4965                                 atomic_inc(&conf->preread_active_stripes);
4966                         raid5_release_stripe(sh_src);
4967                         goto finish;
4968                 }
4969                 if (sh_src)
4970                         raid5_release_stripe(sh_src);
4971
4972                 sh->reconstruct_state = reconstruct_state_idle;
4973                 clear_bit(STRIPE_EXPANDING, &sh->state);
4974                 for (i = conf->raid_disks; i--; ) {
4975                         set_bit(R5_Wantwrite, &sh->dev[i].flags);
4976                         set_bit(R5_LOCKED, &sh->dev[i].flags);
4977                         s.locked++;
4978                 }
4979         }
4980
4981         if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
4982             !sh->reconstruct_state) {
4983                 /* Need to write out all blocks after computing parity */
4984                 sh->disks = conf->raid_disks;
4985                 stripe_set_idx(sh->sector, conf, 0, sh);
4986                 schedule_reconstruction(sh, &s, 1, 1);
4987         } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
4988                 clear_bit(STRIPE_EXPAND_READY, &sh->state);
4989                 atomic_dec(&conf->reshape_stripes);
4990                 wake_up(&conf->wait_for_overlap);
4991                 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
4992         }
4993
4994         if (s.expanding && s.locked == 0 &&
4995             !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
4996                 handle_stripe_expansion(conf, sh);
4997
4998 finish:
4999         /* wait for this device to become unblocked */
5000         if (unlikely(s.blocked_rdev)) {
5001                 if (conf->mddev->external)
5002                         md_wait_for_blocked_rdev(s.blocked_rdev,
5003                                                  conf->mddev);
5004                 else
5005                         /* Internal metadata will immediately
5006                          * be written by raid5d, so we don't
5007                          * need to wait here.
5008                          */
5009                         rdev_dec_pending(s.blocked_rdev,
5010                                          conf->mddev);
5011         }
5012
5013         if (s.handle_bad_blocks)
5014                 for (i = disks; i--; ) {
5015                         struct md_rdev *rdev;
5016                         struct r5dev *dev = &sh->dev[i];
5017                         if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
5018                                 /* We own a safe reference to the rdev */
5019                                 rdev = conf->disks[i].rdev;
5020                                 if (!rdev_set_badblocks(rdev, sh->sector,
5021                                                         STRIPE_SECTORS, 0))
5022                                         md_error(conf->mddev, rdev);
5023                                 rdev_dec_pending(rdev, conf->mddev);
5024                         }
5025                         if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
5026                                 rdev = conf->disks[i].rdev;
5027                                 rdev_clear_badblocks(rdev, sh->sector,
5028                                                      STRIPE_SECTORS, 0);
5029                                 rdev_dec_pending(rdev, conf->mddev);
5030                         }
5031                         if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
5032                                 rdev = conf->disks[i].replacement;
5033                                 if (!rdev)
5034                                         /* rdev have been moved down */
5035                                         rdev = conf->disks[i].rdev;
5036                                 rdev_clear_badblocks(rdev, sh->sector,
5037                                                      STRIPE_SECTORS, 0);
5038                                 rdev_dec_pending(rdev, conf->mddev);
5039                         }
5040                 }
5041
5042         if (s.ops_request)
5043                 raid_run_ops(sh, s.ops_request);
5044
5045         ops_run_io(sh, &s);
5046
5047         if (s.dec_preread_active) {
5048                 /* We delay this until after ops_run_io so that if make_request
5049                  * is waiting on a flush, it won't continue until the writes
5050                  * have actually been submitted.
5051                  */
5052                 atomic_dec(&conf->preread_active_stripes);
5053                 if (atomic_read(&conf->preread_active_stripes) <
5054                     IO_THRESHOLD)
5055                         md_wakeup_thread(conf->mddev->thread);
5056         }
5057
5058         clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
5059 }
5060
5061 static void raid5_activate_delayed(struct r5conf *conf)
5062 {
5063         if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
5064                 while (!list_empty(&conf->delayed_list)) {
5065                         struct list_head *l = conf->delayed_list.next;
5066                         struct stripe_head *sh;
5067                         sh = list_entry(l, struct stripe_head, lru);
5068                         list_del_init(l);
5069                         clear_bit(STRIPE_DELAYED, &sh->state);
5070                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5071                                 atomic_inc(&conf->preread_active_stripes);
5072                         list_add_tail(&sh->lru, &conf->hold_list);
5073                         raid5_wakeup_stripe_thread(sh);
5074                 }
5075         }
5076 }
5077
5078 static void activate_bit_delay(struct r5conf *conf,
5079         struct list_head *temp_inactive_list)
5080 {
5081         /* device_lock is held */
5082         struct list_head head;
5083         list_add(&head, &conf->bitmap_list);
5084         list_del_init(&conf->bitmap_list);
5085         while (!list_empty(&head)) {
5086                 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
5087                 int hash;
5088                 list_del_init(&sh->lru);
5089                 atomic_inc(&sh->count);
5090                 hash = sh->hash_lock_index;
5091                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
5092         }
5093 }
5094
5095 static int raid5_congested(struct mddev *mddev, int bits)
5096 {
5097         struct r5conf *conf = mddev->private;
5098
5099         /* No difference between reads and writes.  Just check
5100          * how busy the stripe_cache is
5101          */
5102
5103         if (test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
5104                 return 1;
5105
5106         /* Also checks whether there is pressure on r5cache log space */
5107         if (test_bit(R5C_LOG_TIGHT, &conf->cache_state))
5108                 return 1;
5109         if (conf->quiesce)
5110                 return 1;
5111         if (atomic_read(&conf->empty_inactive_list_nr))
5112                 return 1;
5113
5114         return 0;
5115 }
5116
5117 static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
5118 {
5119         struct r5conf *conf = mddev->private;
5120         sector_t sector = bio->bi_iter.bi_sector;
5121         unsigned int chunk_sectors;
5122         unsigned int bio_sectors = bio_sectors(bio);
5123
5124         WARN_ON_ONCE(bio->bi_partno);
5125
5126         chunk_sectors = min(conf->chunk_sectors, conf->prev_chunk_sectors);
5127         return  chunk_sectors >=
5128                 ((sector & (chunk_sectors - 1)) + bio_sectors);
5129 }
5130
5131 /*
5132  *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
5133  *  later sampled by raid5d.
5134  */
5135 static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
5136 {
5137         unsigned long flags;
5138
5139         spin_lock_irqsave(&conf->device_lock, flags);
5140
5141         bi->bi_next = conf->retry_read_aligned_list;
5142         conf->retry_read_aligned_list = bi;
5143
5144         spin_unlock_irqrestore(&conf->device_lock, flags);
5145         md_wakeup_thread(conf->mddev->thread);
5146 }
5147
5148 static struct bio *remove_bio_from_retry(struct r5conf *conf,
5149                                          unsigned int *offset)
5150 {
5151         struct bio *bi;
5152
5153         bi = conf->retry_read_aligned;
5154         if (bi) {
5155                 *offset = conf->retry_read_offset;
5156                 conf->retry_read_aligned = NULL;
5157                 return bi;
5158         }
5159         bi = conf->retry_read_aligned_list;
5160         if(bi) {
5161                 conf->retry_read_aligned_list = bi->bi_next;
5162                 bi->bi_next = NULL;
5163                 *offset = 0;
5164         }
5165
5166         return bi;
5167 }
5168
5169 /*
5170  *  The "raid5_align_endio" should check if the read succeeded and if it
5171  *  did, call bio_endio on the original bio (having bio_put the new bio
5172  *  first).
5173  *  If the read failed..
5174  */
5175 static void raid5_align_endio(struct bio *bi)
5176 {
5177         struct bio* raid_bi  = bi->bi_private;
5178         struct mddev *mddev;
5179         struct r5conf *conf;
5180         struct md_rdev *rdev;
5181         blk_status_t error = bi->bi_status;
5182
5183         bio_put(bi);
5184
5185         rdev = (void*)raid_bi->bi_next;
5186         raid_bi->bi_next = NULL;
5187         mddev = rdev->mddev;
5188         conf = mddev->private;
5189
5190         rdev_dec_pending(rdev, conf->mddev);
5191
5192         if (!error) {
5193                 bio_endio(raid_bi);
5194                 if (atomic_dec_and_test(&conf->active_aligned_reads))
5195                         wake_up(&conf->wait_for_quiescent);
5196                 return;
5197         }
5198
5199         pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
5200
5201         add_bio_to_retry(raid_bi, conf);
5202 }
5203
5204 static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
5205 {
5206         struct r5conf *conf = mddev->private;
5207         int dd_idx;
5208         struct bio* align_bi;
5209         struct md_rdev *rdev;
5210         sector_t end_sector;
5211
5212         if (!in_chunk_boundary(mddev, raid_bio)) {
5213                 pr_debug("%s: non aligned\n", __func__);
5214                 return 0;
5215         }
5216         /*
5217          * use bio_clone_fast to make a copy of the bio
5218          */
5219         align_bi = bio_clone_fast(raid_bio, GFP_NOIO, &mddev->bio_set);
5220         if (!align_bi)
5221                 return 0;
5222         /*
5223          *   set bi_end_io to a new function, and set bi_private to the
5224          *     original bio.
5225          */
5226         align_bi->bi_end_io  = raid5_align_endio;
5227         align_bi->bi_private = raid_bio;
5228         /*
5229          *      compute position
5230          */
5231         align_bi->bi_iter.bi_sector =
5232                 raid5_compute_sector(conf, raid_bio->bi_iter.bi_sector,
5233                                      0, &dd_idx, NULL);
5234
5235         end_sector = bio_end_sector(align_bi);
5236         rcu_read_lock();
5237         rdev = rcu_dereference(conf->disks[dd_idx].replacement);
5238         if (!rdev || test_bit(Faulty, &rdev->flags) ||
5239             rdev->recovery_offset < end_sector) {
5240                 rdev = rcu_dereference(conf->disks[dd_idx].rdev);
5241                 if (rdev &&
5242                     (test_bit(Faulty, &rdev->flags) ||
5243                     !(test_bit(In_sync, &rdev->flags) ||
5244                       rdev->recovery_offset >= end_sector)))
5245                         rdev = NULL;
5246         }
5247
5248         if (r5c_big_stripe_cached(conf, align_bi->bi_iter.bi_sector)) {
5249                 rcu_read_unlock();
5250                 bio_put(align_bi);
5251                 return 0;
5252         }
5253
5254         if (rdev) {
5255                 sector_t first_bad;
5256                 int bad_sectors;
5257
5258                 atomic_inc(&rdev->nr_pending);
5259                 rcu_read_unlock();
5260                 raid_bio->bi_next = (void*)rdev;
5261                 bio_set_dev(align_bi, rdev->bdev);
5262                 bio_clear_flag(align_bi, BIO_SEG_VALID);
5263
5264                 if (is_badblock(rdev, align_bi->bi_iter.bi_sector,
5265                                 bio_sectors(align_bi),
5266                                 &first_bad, &bad_sectors)) {
5267                         bio_put(align_bi);
5268                         rdev_dec_pending(rdev, mddev);
5269                         return 0;
5270                 }
5271
5272                 /* No reshape active, so we can trust rdev->data_offset */
5273                 align_bi->bi_iter.bi_sector += rdev->data_offset;
5274
5275                 spin_lock_irq(&conf->device_lock);
5276                 wait_event_lock_irq(conf->wait_for_quiescent,
5277                                     conf->quiesce == 0,
5278                                     conf->device_lock);
5279                 atomic_inc(&conf->active_aligned_reads);
5280                 spin_unlock_irq(&conf->device_lock);
5281
5282                 if (mddev->gendisk)
5283                         trace_block_bio_remap(align_bi->bi_disk->queue,
5284                                               align_bi, disk_devt(mddev->gendisk),
5285                                               raid_bio->bi_iter.bi_sector);
5286                 generic_make_request(align_bi);
5287                 return 1;
5288         } else {
5289                 rcu_read_unlock();
5290                 bio_put(align_bi);
5291                 return 0;
5292         }
5293 }
5294
5295 static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
5296 {
5297         struct bio *split;
5298         sector_t sector = raid_bio->bi_iter.bi_sector;
5299         unsigned chunk_sects = mddev->chunk_sectors;
5300         unsigned sectors = chunk_sects - (sector & (chunk_sects-1));
5301
5302         if (sectors < bio_sectors(raid_bio)) {
5303                 struct r5conf *conf = mddev->private;
5304                 split = bio_split(raid_bio, sectors, GFP_NOIO, &conf->bio_split);
5305                 bio_chain(split, raid_bio);
5306                 generic_make_request(raid_bio);
5307                 raid_bio = split;
5308         }
5309
5310         if (!raid5_read_one_chunk(mddev, raid_bio))
5311                 return raid_bio;
5312
5313         return NULL;
5314 }
5315
5316 /* __get_priority_stripe - get the next stripe to process
5317  *
5318  * Full stripe writes are allowed to pass preread active stripes up until
5319  * the bypass_threshold is exceeded.  In general the bypass_count
5320  * increments when the handle_list is handled before the hold_list; however, it
5321  * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
5322  * stripe with in flight i/o.  The bypass_count will be reset when the
5323  * head of the hold_list has changed, i.e. the head was promoted to the
5324  * handle_list.
5325  */
5326 static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group)
5327 {
5328         struct stripe_head *sh, *tmp;
5329         struct list_head *handle_list = NULL;
5330         struct r5worker_group *wg;
5331         bool second_try = !r5c_is_writeback(conf->log) &&
5332                 !r5l_log_disk_error(conf);
5333         bool try_loprio = test_bit(R5C_LOG_TIGHT, &conf->cache_state) ||
5334                 r5l_log_disk_error(conf);
5335
5336 again:
5337         wg = NULL;
5338         sh = NULL;
5339         if (conf->worker_cnt_per_group == 0) {
5340                 handle_list = try_loprio ? &conf->loprio_list :
5341                                         &conf->handle_list;
5342         } else if (group != ANY_GROUP) {
5343                 handle_list = try_loprio ? &conf->worker_groups[group].loprio_list :
5344                                 &conf->worker_groups[group].handle_list;
5345                 wg = &conf->worker_groups[group];
5346         } else {
5347                 int i;
5348                 for (i = 0; i < conf->group_cnt; i++) {
5349                         handle_list = try_loprio ? &conf->worker_groups[i].loprio_list :
5350                                 &conf->worker_groups[i].handle_list;
5351                         wg = &conf->worker_groups[i];
5352                         if (!list_empty(handle_list))
5353                                 break;
5354                 }
5355         }
5356
5357         pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
5358                   __func__,
5359                   list_empty(handle_list) ? "empty" : "busy",
5360                   list_empty(&conf->hold_list) ? "empty" : "busy",
5361                   atomic_read(&conf->pending_full_writes), conf->bypass_count);
5362
5363         if (!list_empty(handle_list)) {
5364                 sh = list_entry(handle_list->next, typeof(*sh), lru);
5365
5366                 if (list_empty(&conf->hold_list))
5367                         conf->bypass_count = 0;
5368                 else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
5369                         if (conf->hold_list.next == conf->last_hold)
5370                                 conf->bypass_count++;
5371                         else {
5372                                 conf->last_hold = conf->hold_list.next;
5373                                 conf->bypass_count -= conf->bypass_threshold;
5374                                 if (conf->bypass_count < 0)
5375                                         conf->bypass_count = 0;
5376                         }
5377                 }
5378         } else if (!list_empty(&conf->hold_list) &&
5379                    ((conf->bypass_threshold &&
5380                      conf->bypass_count > conf->bypass_threshold) ||
5381                     atomic_read(&conf->pending_full_writes) == 0)) {
5382
5383                 list_for_each_entry(tmp, &conf->hold_list,  lru) {
5384                         if (conf->worker_cnt_per_group == 0 ||
5385                             group == ANY_GROUP ||
5386                             !cpu_online(tmp->cpu) ||
5387                             cpu_to_group(tmp->cpu) == group) {
5388                                 sh = tmp;
5389                                 break;
5390                         }
5391                 }
5392
5393                 if (sh) {
5394                         conf->bypass_count -= conf->bypass_threshold;
5395                         if (conf->bypass_count < 0)
5396                                 conf->bypass_count = 0;
5397                 }
5398                 wg = NULL;
5399         }
5400
5401         if (!sh) {
5402                 if (second_try)
5403                         return NULL;
5404                 second_try = true;
5405                 try_loprio = !try_loprio;
5406                 goto again;
5407         }
5408
5409         if (wg) {
5410                 wg->stripes_cnt--;
5411                 sh->group = NULL;
5412         }
5413         list_del_init(&sh->lru);
5414         BUG_ON(atomic_inc_return(&sh->count) != 1);
5415         return sh;
5416 }
5417
5418 struct raid5_plug_cb {
5419         struct blk_plug_cb      cb;
5420         struct list_head        list;
5421         struct list_head        temp_inactive_list[NR_STRIPE_HASH_LOCKS];
5422 };
5423
5424 static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
5425 {
5426         struct raid5_plug_cb *cb = container_of(
5427                 blk_cb, struct raid5_plug_cb, cb);
5428         struct stripe_head *sh;
5429         struct mddev *mddev = cb->cb.data;
5430         struct r5conf *conf = mddev->private;
5431         int cnt = 0;
5432         int hash;
5433
5434         if (cb->list.next && !list_empty(&cb->list)) {
5435                 spin_lock_irq(&conf->device_lock);
5436                 while (!list_empty(&cb->list)) {
5437                         sh = list_first_entry(&cb->list, struct stripe_head, lru);
5438                         list_del_init(&sh->lru);
5439                         /*
5440                          * avoid race release_stripe_plug() sees
5441                          * STRIPE_ON_UNPLUG_LIST clear but the stripe
5442                          * is still in our list
5443                          */
5444                         smp_mb__before_atomic();
5445                         clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
5446                         /*
5447                          * STRIPE_ON_RELEASE_LIST could be set here. In that
5448                          * case, the count is always > 1 here
5449                          */
5450                         hash = sh->hash_lock_index;
5451                         __release_stripe(conf, sh, &cb->temp_inactive_list[hash]);
5452                         cnt++;
5453                 }
5454                 spin_unlock_irq(&conf->device_lock);
5455         }
5456         release_inactive_stripe_list(conf, cb->temp_inactive_list,
5457                                      NR_STRIPE_HASH_LOCKS);
5458         if (mddev->queue)
5459                 trace_block_unplug(mddev->queue, cnt, !from_schedule);
5460         kfree(cb);
5461 }
5462
5463 static void release_stripe_plug(struct mddev *mddev,
5464                                 struct stripe_head *sh)
5465 {
5466         struct blk_plug_cb *blk_cb = blk_check_plugged(
5467                 raid5_unplug, mddev,
5468                 sizeof(struct raid5_plug_cb));
5469         struct raid5_plug_cb *cb;
5470
5471         if (!blk_cb) {
5472                 raid5_release_stripe(sh);
5473                 return;
5474         }
5475
5476         cb = container_of(blk_cb, struct raid5_plug_cb, cb);
5477
5478         if (cb->list.next == NULL) {
5479                 int i;
5480                 INIT_LIST_HEAD(&cb->list);
5481                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
5482                         INIT_LIST_HEAD(cb->temp_inactive_list + i);
5483         }
5484
5485         if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
5486                 list_add_tail(&sh->lru, &cb->list);
5487         else
5488                 raid5_release_stripe(sh);
5489 }
5490
5491 static void make_discard_request(struct mddev *mddev, struct bio *bi)
5492 {
5493         struct r5conf *conf = mddev->private;
5494         sector_t logical_sector, last_sector;
5495         struct stripe_head *sh;
5496         int stripe_sectors;
5497
5498         if (mddev->reshape_position != MaxSector)
5499                 /* Skip discard while reshape is happening */
5500                 return;
5501
5502         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
5503         last_sector = bi->bi_iter.bi_sector + (bi->bi_iter.bi_size>>9);
5504
5505         bi->bi_next = NULL;
5506
5507         stripe_sectors = conf->chunk_sectors *
5508                 (conf->raid_disks - conf->max_degraded);
5509         logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
5510                                                stripe_sectors);
5511         sector_div(last_sector, stripe_sectors);
5512
5513         logical_sector *= conf->chunk_sectors;
5514         last_sector *= conf->chunk_sectors;
5515
5516         for (; logical_sector < last_sector;
5517              logical_sector += STRIPE_SECTORS) {
5518                 DEFINE_WAIT(w);
5519                 int d;
5520         again:
5521                 sh = raid5_get_active_stripe(conf, logical_sector, 0, 0, 0);
5522                 prepare_to_wait(&conf->wait_for_overlap, &w,
5523                                 TASK_UNINTERRUPTIBLE);
5524                 set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5525                 if (test_bit(STRIPE_SYNCING, &sh->state)) {
5526                         raid5_release_stripe(sh);
5527                         schedule();
5528                         goto again;
5529                 }
5530                 clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5531                 spin_lock_irq(&sh->stripe_lock);
5532                 for (d = 0; d < conf->raid_disks; d++) {
5533                         if (d == sh->pd_idx || d == sh->qd_idx)
5534                                 continue;
5535                         if (sh->dev[d].towrite || sh->dev[d].toread) {
5536                                 set_bit(R5_Overlap, &sh->dev[d].flags);
5537                                 spin_unlock_irq(&sh->stripe_lock);
5538                                 raid5_release_stripe(sh);
5539                                 schedule();
5540                                 goto again;
5541                         }
5542                 }
5543                 set_bit(STRIPE_DISCARD, &sh->state);
5544                 finish_wait(&conf->wait_for_overlap, &w);
5545                 sh->overwrite_disks = 0;
5546                 for (d = 0; d < conf->raid_disks; d++) {
5547                         if (d == sh->pd_idx || d == sh->qd_idx)
5548                                 continue;
5549                         sh->dev[d].towrite = bi;
5550                         set_bit(R5_OVERWRITE, &sh->dev[d].flags);
5551                         bio_inc_remaining(bi);
5552                         md_write_inc(mddev, bi);
5553                         sh->overwrite_disks++;
5554                 }
5555                 spin_unlock_irq(&sh->stripe_lock);
5556                 if (conf->mddev->bitmap) {
5557                         for (d = 0;
5558                              d < conf->raid_disks - conf->max_degraded;
5559                              d++)
5560                                 md_bitmap_startwrite(mddev->bitmap,
5561                                                      sh->sector,
5562                                                      STRIPE_SECTORS,
5563                                                      0);
5564                         sh->bm_seq = conf->seq_flush + 1;
5565                         set_bit(STRIPE_BIT_DELAY, &sh->state);
5566                 }
5567
5568                 set_bit(STRIPE_HANDLE, &sh->state);
5569                 clear_bit(STRIPE_DELAYED, &sh->state);
5570                 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5571                         atomic_inc(&conf->preread_active_stripes);
5572                 release_stripe_plug(mddev, sh);
5573         }
5574
5575         bio_endio(bi);
5576 }
5577
5578 static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
5579 {
5580         struct r5conf *conf = mddev->private;
5581         int dd_idx;
5582         sector_t new_sector;
5583         sector_t logical_sector, last_sector;
5584         struct stripe_head *sh;
5585         const int rw = bio_data_dir(bi);
5586         DEFINE_WAIT(w);
5587         bool do_prepare;
5588         bool do_flush = false;
5589
5590         if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
5591                 int ret = log_handle_flush_request(conf, bi);
5592
5593                 if (ret == 0)
5594                         return true;
5595                 if (ret == -ENODEV) {
5596                         md_flush_request(mddev, bi);
5597                         return true;
5598                 }
5599                 /* ret == -EAGAIN, fallback */
5600                 /*
5601                  * if r5l_handle_flush_request() didn't clear REQ_PREFLUSH,
5602                  * we need to flush journal device
5603                  */
5604                 do_flush = bi->bi_opf & REQ_PREFLUSH;
5605         }
5606
5607         if (!md_write_start(mddev, bi))
5608                 return false;
5609         /*
5610          * If array is degraded, better not do chunk aligned read because
5611          * later we might have to read it again in order to reconstruct
5612          * data on failed drives.
5613          */
5614         if (rw == READ && mddev->degraded == 0 &&
5615             mddev->reshape_position == MaxSector) {
5616                 bi = chunk_aligned_read(mddev, bi);
5617                 if (!bi)
5618                         return true;
5619         }
5620
5621         if (unlikely(bio_op(bi) == REQ_OP_DISCARD)) {
5622                 make_discard_request(mddev, bi);
5623                 md_write_end(mddev);
5624                 return true;
5625         }
5626
5627         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
5628         last_sector = bio_end_sector(bi);
5629         bi->bi_next = NULL;
5630
5631         prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
5632         for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
5633                 int previous;
5634                 int seq;
5635
5636                 do_prepare = false;
5637         retry:
5638                 seq = read_seqcount_begin(&conf->gen_lock);
5639                 previous = 0;
5640                 if (do_prepare)
5641                         prepare_to_wait(&conf->wait_for_overlap, &w,
5642                                 TASK_UNINTERRUPTIBLE);
5643                 if (unlikely(conf->reshape_progress != MaxSector)) {
5644                         /* spinlock is needed as reshape_progress may be
5645                          * 64bit on a 32bit platform, and so it might be
5646                          * possible to see a half-updated value
5647                          * Of course reshape_progress could change after
5648                          * the lock is dropped, so once we get a reference
5649                          * to the stripe that we think it is, we will have
5650                          * to check again.
5651                          */
5652                         spin_lock_irq(&conf->device_lock);
5653                         if (mddev->reshape_backwards
5654                             ? logical_sector < conf->reshape_progress
5655                             : logical_sector >= conf->reshape_progress) {
5656                                 previous = 1;
5657                         } else {
5658                                 if (mddev->reshape_backwards
5659                                     ? logical_sector < conf->reshape_safe
5660                                     : logical_sector >= conf->reshape_safe) {
5661                                         spin_unlock_irq(&conf->device_lock);
5662                                         schedule();
5663                                         do_prepare = true;
5664                                         goto retry;
5665                                 }
5666                         }
5667                         spin_unlock_irq(&conf->device_lock);
5668                 }
5669
5670                 new_sector = raid5_compute_sector(conf, logical_sector,
5671                                                   previous,
5672                                                   &dd_idx, NULL);
5673                 pr_debug("raid456: raid5_make_request, sector %llu logical %llu\n",
5674                         (unsigned long long)new_sector,
5675                         (unsigned long long)logical_sector);
5676
5677                 sh = raid5_get_active_stripe(conf, new_sector, previous,
5678                                        (bi->bi_opf & REQ_RAHEAD), 0);
5679                 if (sh) {
5680                         if (unlikely(previous)) {
5681                                 /* expansion might have moved on while waiting for a
5682                                  * stripe, so we must do the range check again.
5683                                  * Expansion could still move past after this
5684                                  * test, but as we are holding a reference to
5685                                  * 'sh', we know that if that happens,
5686                                  *  STRIPE_EXPANDING will get set and the expansion
5687                                  * won't proceed until we finish with the stripe.
5688                                  */
5689                                 int must_retry = 0;
5690                                 spin_lock_irq(&conf->device_lock);
5691                                 if (mddev->reshape_backwards
5692                                     ? logical_sector >= conf->reshape_progress
5693                                     : logical_sector < conf->reshape_progress)
5694                                         /* mismatch, need to try again */
5695                                         must_retry = 1;
5696                                 spin_unlock_irq(&conf->device_lock);
5697                                 if (must_retry) {
5698                                         raid5_release_stripe(sh);
5699                                         schedule();
5700                                         do_prepare = true;
5701                                         goto retry;
5702                                 }
5703                         }
5704                         if (read_seqcount_retry(&conf->gen_lock, seq)) {
5705                                 /* Might have got the wrong stripe_head
5706                                  * by accident
5707                                  */
5708                                 raid5_release_stripe(sh);
5709                                 goto retry;
5710                         }
5711
5712                         if (test_bit(STRIPE_EXPANDING, &sh->state) ||
5713                             !add_stripe_bio(sh, bi, dd_idx, rw, previous)) {
5714                                 /* Stripe is busy expanding or
5715                                  * add failed due to overlap.  Flush everything
5716                                  * and wait a while
5717                                  */
5718                                 md_wakeup_thread(mddev->thread);
5719                                 raid5_release_stripe(sh);
5720                                 schedule();
5721                                 do_prepare = true;
5722                                 goto retry;
5723                         }
5724                         if (do_flush) {
5725                                 set_bit(STRIPE_R5C_PREFLUSH, &sh->state);
5726                                 /* we only need flush for one stripe */
5727                                 do_flush = false;
5728                         }
5729
5730                         set_bit(STRIPE_HANDLE, &sh->state);
5731                         clear_bit(STRIPE_DELAYED, &sh->state);
5732                         if ((!sh->batch_head || sh == sh->batch_head) &&
5733                             (bi->bi_opf & REQ_SYNC) &&
5734                             !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5735                                 atomic_inc(&conf->preread_active_stripes);
5736                         release_stripe_plug(mddev, sh);
5737                 } else {
5738                         /* cannot get stripe for read-ahead, just give-up */
5739                         bi->bi_status = BLK_STS_IOERR;
5740                         break;
5741                 }
5742         }
5743         finish_wait(&conf->wait_for_overlap, &w);
5744
5745         if (rw == WRITE)
5746                 md_write_end(mddev);
5747         bio_endio(bi);
5748         return true;
5749 }
5750
5751 static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
5752
5753 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
5754 {
5755         /* reshaping is quite different to recovery/resync so it is
5756          * handled quite separately ... here.
5757          *
5758          * On each call to sync_request, we gather one chunk worth of
5759          * destination stripes and flag them as expanding.
5760          * Then we find all the source stripes and request reads.
5761          * As the reads complete, handle_stripe will copy the data
5762          * into the destination stripe and release that stripe.
5763          */
5764         struct r5conf *conf = mddev->private;
5765         struct stripe_head *sh;
5766         struct md_rdev *rdev;
5767         sector_t first_sector, last_sector;
5768         int raid_disks = conf->previous_raid_disks;
5769         int data_disks = raid_disks - conf->max_degraded;
5770         int new_data_disks = conf->raid_disks - conf->max_degraded;
5771         int i;
5772         int dd_idx;
5773         sector_t writepos, readpos, safepos;
5774         sector_t stripe_addr;
5775         int reshape_sectors;
5776         struct list_head stripes;
5777         sector_t retn;
5778
5779         if (sector_nr == 0) {
5780                 /* If restarting in the middle, skip the initial sectors */
5781                 if (mddev->reshape_backwards &&
5782                     conf->reshape_progress < raid5_size(mddev, 0, 0)) {
5783                         sector_nr = raid5_size(mddev, 0, 0)
5784                                 - conf->reshape_progress;
5785                 } else if (mddev->reshape_backwards &&
5786                            conf->reshape_progress == MaxSector) {
5787                         /* shouldn't happen, but just in case, finish up.*/
5788                         sector_nr = MaxSector;
5789                 } else if (!mddev->reshape_backwards &&
5790                            conf->reshape_progress > 0)
5791                         sector_nr = conf->reshape_progress;
5792                 sector_div(sector_nr, new_data_disks);
5793                 if (sector_nr) {
5794                         mddev->curr_resync_completed = sector_nr;
5795                         sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5796                         *skipped = 1;
5797                         retn = sector_nr;
5798                         goto finish;
5799                 }
5800         }
5801
5802         /* We need to process a full chunk at a time.
5803          * If old and new chunk sizes differ, we need to process the
5804          * largest of these
5805          */
5806
5807         reshape_sectors = max(conf->chunk_sectors, conf->prev_chunk_sectors);
5808
5809         /* We update the metadata at least every 10 seconds, or when
5810          * the data about to be copied would over-write the source of
5811          * the data at the front of the range.  i.e. one new_stripe
5812          * along from reshape_progress new_maps to after where
5813          * reshape_safe old_maps to
5814          */
5815         writepos = conf->reshape_progress;
5816         sector_div(writepos, new_data_disks);
5817         readpos = conf->reshape_progress;
5818         sector_div(readpos, data_disks);
5819         safepos = conf->reshape_safe;
5820         sector_div(safepos, data_disks);
5821         if (mddev->reshape_backwards) {
5822                 BUG_ON(writepos < reshape_sectors);
5823                 writepos -= reshape_sectors;
5824                 readpos += reshape_sectors;
5825                 safepos += reshape_sectors;
5826         } else {
5827                 writepos += reshape_sectors;
5828                 /* readpos and safepos are worst-case calculations.
5829                  * A negative number is overly pessimistic, and causes
5830                  * obvious problems for unsigned storage.  So clip to 0.
5831                  */
5832                 readpos -= min_t(sector_t, reshape_sectors, readpos);
5833                 safepos -= min_t(sector_t, reshape_sectors, safepos);
5834         }
5835
5836         /* Having calculated the 'writepos' possibly use it
5837          * to set 'stripe_addr' which is where we will write to.
5838          */
5839         if (mddev->reshape_backwards) {
5840                 BUG_ON(conf->reshape_progress == 0);
5841                 stripe_addr = writepos;
5842                 BUG_ON((mddev->dev_sectors &
5843                         ~((sector_t)reshape_sectors - 1))
5844                        - reshape_sectors - stripe_addr
5845                        != sector_nr);
5846         } else {
5847                 BUG_ON(writepos != sector_nr + reshape_sectors);
5848                 stripe_addr = sector_nr;
5849         }
5850
5851         /* 'writepos' is the most advanced device address we might write.
5852          * 'readpos' is the least advanced device address we might read.
5853          * 'safepos' is the least address recorded in the metadata as having
5854          *     been reshaped.
5855          * If there is a min_offset_diff, these are adjusted either by
5856          * increasing the safepos/readpos if diff is negative, or
5857          * increasing writepos if diff is positive.
5858          * If 'readpos' is then behind 'writepos', there is no way that we can
5859          * ensure safety in the face of a crash - that must be done by userspace
5860          * making a backup of the data.  So in that case there is no particular
5861          * rush to update metadata.
5862          * Otherwise if 'safepos' is behind 'writepos', then we really need to
5863          * update the metadata to advance 'safepos' to match 'readpos' so that
5864          * we can be safe in the event of a crash.
5865          * So we insist on updating metadata if safepos is behind writepos and
5866          * readpos is beyond writepos.
5867          * In any case, update the metadata every 10 seconds.
5868          * Maybe that number should be configurable, but I'm not sure it is
5869          * worth it.... maybe it could be a multiple of safemode_delay???
5870          */
5871         if (conf->min_offset_diff < 0) {
5872                 safepos += -conf->min_offset_diff;
5873                 readpos += -conf->min_offset_diff;
5874         } else
5875                 writepos += conf->min_offset_diff;
5876
5877         if ((mddev->reshape_backwards
5878              ? (safepos > writepos && readpos < writepos)
5879              : (safepos < writepos && readpos > writepos)) ||
5880             time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
5881                 /* Cannot proceed until we've updated the superblock... */
5882                 wait_event(conf->wait_for_overlap,
5883                            atomic_read(&conf->reshape_stripes)==0
5884                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5885                 if (atomic_read(&conf->reshape_stripes) != 0)
5886                         return 0;
5887                 mddev->reshape_position = conf->reshape_progress;
5888                 mddev->curr_resync_completed = sector_nr;
5889                 if (!mddev->reshape_backwards)
5890                         /* Can update recovery_offset */
5891                         rdev_for_each(rdev, mddev)
5892                                 if (rdev->raid_disk >= 0 &&
5893                                     !test_bit(Journal, &rdev->flags) &&
5894                                     !test_bit(In_sync, &rdev->flags) &&
5895                                     rdev->recovery_offset < sector_nr)
5896                                         rdev->recovery_offset = sector_nr;
5897
5898                 conf->reshape_checkpoint = jiffies;
5899                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
5900                 md_wakeup_thread(mddev->thread);
5901                 wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
5902                            test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5903                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5904                         return 0;
5905                 spin_lock_irq(&conf->device_lock);
5906                 conf->reshape_safe = mddev->reshape_position;
5907                 spin_unlock_irq(&conf->device_lock);
5908                 wake_up(&conf->wait_for_overlap);
5909                 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5910         }
5911
5912         INIT_LIST_HEAD(&stripes);
5913         for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
5914                 int j;
5915                 int skipped_disk = 0;
5916                 sh = raid5_get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
5917                 set_bit(STRIPE_EXPANDING, &sh->state);
5918                 atomic_inc(&conf->reshape_stripes);
5919                 /* If any of this stripe is beyond the end of the old
5920                  * array, then we need to zero those blocks
5921                  */
5922                 for (j=sh->disks; j--;) {
5923                         sector_t s;
5924                         if (j == sh->pd_idx)
5925                                 continue;
5926                         if (conf->level == 6 &&
5927                             j == sh->qd_idx)
5928                                 continue;
5929                         s = raid5_compute_blocknr(sh, j, 0);
5930                         if (s < raid5_size(mddev, 0, 0)) {
5931                                 skipped_disk = 1;
5932                                 continue;
5933                         }
5934                         memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE);
5935                         set_bit(R5_Expanded, &sh->dev[j].flags);
5936                         set_bit(R5_UPTODATE, &sh->dev[j].flags);
5937                 }
5938                 if (!skipped_disk) {
5939                         set_bit(STRIPE_EXPAND_READY, &sh->state);
5940                         set_bit(STRIPE_HANDLE, &sh->state);
5941                 }
5942                 list_add(&sh->lru, &stripes);
5943         }
5944         spin_lock_irq(&conf->device_lock);
5945         if (mddev->reshape_backwards)
5946                 conf->reshape_progress -= reshape_sectors * new_data_disks;
5947         else
5948                 conf->reshape_progress += reshape_sectors * new_data_disks;
5949         spin_unlock_irq(&conf->device_lock);
5950         /* Ok, those stripe are ready. We can start scheduling
5951          * reads on the source stripes.
5952          * The source stripes are determined by mapping the first and last
5953          * block on the destination stripes.
5954          */
5955         first_sector =
5956                 raid5_compute_sector(conf, stripe_addr*(new_data_disks),
5957                                      1, &dd_idx, NULL);
5958         last_sector =
5959                 raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
5960                                             * new_data_disks - 1),
5961                                      1, &dd_idx, NULL);
5962         if (last_sector >= mddev->dev_sectors)
5963                 last_sector = mddev->dev_sectors - 1;
5964         while (first_sector <= last_sector) {
5965                 sh = raid5_get_active_stripe(conf, first_sector, 1, 0, 1);
5966                 set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
5967                 set_bit(STRIPE_HANDLE, &sh->state);
5968                 raid5_release_stripe(sh);
5969                 first_sector += STRIPE_SECTORS;
5970         }
5971         /* Now that the sources are clearly marked, we can release
5972          * the destination stripes
5973          */
5974         while (!list_empty(&stripes)) {
5975                 sh = list_entry(stripes.next, struct stripe_head, lru);
5976                 list_del_init(&sh->lru);
5977                 raid5_release_stripe(sh);
5978         }
5979         /* If this takes us to the resync_max point where we have to pause,
5980          * then we need to write out the superblock.
5981          */
5982         sector_nr += reshape_sectors;
5983         retn = reshape_sectors;
5984 finish:
5985         if (mddev->curr_resync_completed > mddev->resync_max ||
5986             (sector_nr - mddev->curr_resync_completed) * 2
5987             >= mddev->resync_max - mddev->curr_resync_completed) {
5988                 /* Cannot proceed until we've updated the superblock... */
5989                 wait_event(conf->wait_for_overlap,
5990                            atomic_read(&conf->reshape_stripes) == 0
5991                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5992                 if (atomic_read(&conf->reshape_stripes) != 0)
5993                         goto ret;
5994                 mddev->reshape_position = conf->reshape_progress;
5995                 mddev->curr_resync_completed = sector_nr;
5996                 if (!mddev->reshape_backwards)
5997                         /* Can update recovery_offset */
5998                         rdev_for_each(rdev, mddev)
5999                                 if (rdev->raid_disk >= 0 &&
6000                                     !test_bit(Journal, &rdev->flags) &&
6001                                     !test_bit(In_sync, &rdev->flags) &&
6002                                     rdev->recovery_offset < sector_nr)
6003                                         rdev->recovery_offset = sector_nr;
6004                 conf->reshape_checkpoint = jiffies;
6005                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
6006                 md_wakeup_thread(mddev->thread);
6007                 wait_event(mddev->sb_wait,
6008                            !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)
6009                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6010                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6011                         goto ret;
6012                 spin_lock_irq(&conf->device_lock);
6013                 conf->reshape_safe = mddev->reshape_position;
6014                 spin_unlock_irq(&conf->device_lock);
6015                 wake_up(&conf->wait_for_overlap);
6016                 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
6017         }
6018 ret:
6019         return retn;
6020 }
6021
6022 static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_nr,
6023                                           int *skipped)
6024 {
6025         struct r5conf *conf = mddev->private;
6026         struct stripe_head *sh;
6027         sector_t max_sector = mddev->dev_sectors;
6028         sector_t sync_blocks;
6029         int still_degraded = 0;
6030         int i;
6031
6032         if (sector_nr >= max_sector) {
6033                 /* just being told to finish up .. nothing much to do */
6034
6035                 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
6036                         end_reshape(conf);
6037                         return 0;
6038                 }
6039
6040                 if (mddev->curr_resync < max_sector) /* aborted */
6041                         md_bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
6042                                            &sync_blocks, 1);
6043                 else /* completed sync */
6044                         conf->fullsync = 0;
6045                 md_bitmap_close_sync(mddev->bitmap);
6046
6047                 return 0;
6048         }
6049
6050         /* Allow raid5_quiesce to complete */
6051         wait_event(conf->wait_for_overlap, conf->quiesce != 2);
6052
6053         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6054                 return reshape_request(mddev, sector_nr, skipped);
6055
6056         /* No need to check resync_max as we never do more than one
6057          * stripe, and as resync_max will always be on a chunk boundary,
6058          * if the check in md_do_sync didn't fire, there is no chance
6059          * of overstepping resync_max here
6060          */
6061
6062         /* if there is too many failed drives and we are trying
6063          * to resync, then assert that we are finished, because there is
6064          * nothing we can do.
6065          */
6066         if (mddev->degraded >= conf->max_degraded &&
6067             test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
6068                 sector_t rv = mddev->dev_sectors - sector_nr;
6069                 *skipped = 1;
6070                 return rv;
6071         }
6072         if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
6073             !conf->fullsync &&
6074             !md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
6075             sync_blocks >= STRIPE_SECTORS) {
6076                 /* we can skip this block, and probably more */
6077                 sync_blocks /= STRIPE_SECTORS;
6078                 *skipped = 1;
6079                 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
6080         }
6081
6082         md_bitmap_cond_end_sync(mddev->bitmap, sector_nr, false);
6083
6084         sh = raid5_get_active_stripe(conf, sector_nr, 0, 1, 0);
6085         if (sh == NULL) {
6086                 sh = raid5_get_active_stripe(conf, sector_nr, 0, 0, 0);
6087                 /* make sure we don't swamp the stripe cache if someone else
6088                  * is trying to get access
6089                  */
6090                 schedule_timeout_uninterruptible(1);
6091         }
6092         /* Need to check if array will still be degraded after recovery/resync
6093          * Note in case of > 1 drive failures it's possible we're rebuilding
6094          * one drive while leaving another faulty drive in array.
6095          */
6096         rcu_read_lock();
6097         for (i = 0; i < conf->raid_disks; i++) {
6098                 struct md_rdev *rdev = READ_ONCE(conf->disks[i].rdev);
6099
6100                 if (rdev == NULL || test_bit(Faulty, &rdev->flags))
6101                         still_degraded = 1;
6102         }
6103         rcu_read_unlock();
6104
6105         md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
6106
6107         set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
6108         set_bit(STRIPE_HANDLE, &sh->state);
6109
6110         raid5_release_stripe(sh);
6111
6112         return STRIPE_SECTORS;
6113 }
6114
6115 static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio,
6116                                unsigned int offset)
6117 {
6118         /* We may not be able to submit a whole bio at once as there
6119          * may not be enough stripe_heads available.
6120          * We cannot pre-allocate enough stripe_heads as we may need
6121          * more than exist in the cache (if we allow ever large chunks).
6122          * So we do one stripe head at a time and record in
6123          * ->bi_hw_segments how many have been done.
6124          *
6125          * We *know* that this entire raid_bio is in one chunk, so
6126          * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
6127          */
6128         struct stripe_head *sh;
6129         int dd_idx;
6130         sector_t sector, logical_sector, last_sector;
6131         int scnt = 0;
6132         int handled = 0;
6133
6134         logical_sector = raid_bio->bi_iter.bi_sector &
6135                 ~((sector_t)STRIPE_SECTORS-1);
6136         sector = raid5_compute_sector(conf, logical_sector,
6137                                       0, &dd_idx, NULL);
6138         last_sector = bio_end_sector(raid_bio);
6139
6140         for (; logical_sector < last_sector;
6141              logical_sector += STRIPE_SECTORS,
6142                      sector += STRIPE_SECTORS,
6143                      scnt++) {
6144
6145                 if (scnt < offset)
6146                         /* already done this stripe */
6147                         continue;
6148
6149                 sh = raid5_get_active_stripe(conf, sector, 0, 1, 1);
6150
6151                 if (!sh) {
6152                         /* failed to get a stripe - must wait */
6153                         conf->retry_read_aligned = raid_bio;
6154                         conf->retry_read_offset = scnt;
6155                         return handled;
6156                 }
6157
6158                 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0, 0)) {
6159                         raid5_release_stripe(sh);
6160                         conf->retry_read_aligned = raid_bio;
6161                         conf->retry_read_offset = scnt;
6162                         return handled;
6163                 }
6164
6165                 set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
6166                 handle_stripe(sh);
6167                 raid5_release_stripe(sh);
6168                 handled++;
6169         }
6170
6171         bio_endio(raid_bio);
6172
6173         if (atomic_dec_and_test(&conf->active_aligned_reads))
6174                 wake_up(&conf->wait_for_quiescent);
6175         return handled;
6176 }
6177
6178 static int handle_active_stripes(struct r5conf *conf, int group,
6179                                  struct r5worker *worker,
6180                                  struct list_head *temp_inactive_list)
6181                 __releases(&conf->device_lock)
6182                 __acquires(&conf->device_lock)
6183 {
6184         struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
6185         int i, batch_size = 0, hash;
6186         bool release_inactive = false;
6187
6188         while (batch_size < MAX_STRIPE_BATCH &&
6189                         (sh = __get_priority_stripe(conf, group)) != NULL)
6190                 batch[batch_size++] = sh;
6191
6192         if (batch_size == 0) {
6193                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6194                         if (!list_empty(temp_inactive_list + i))
6195                                 break;
6196                 if (i == NR_STRIPE_HASH_LOCKS) {
6197                         spin_unlock_irq(&conf->device_lock);
6198                         log_flush_stripe_to_raid(conf);
6199                         spin_lock_irq(&conf->device_lock);
6200                         return batch_size;
6201                 }
6202                 release_inactive = true;
6203         }
6204         spin_unlock_irq(&conf->device_lock);
6205
6206         release_inactive_stripe_list(conf, temp_inactive_list,
6207                                      NR_STRIPE_HASH_LOCKS);
6208
6209         r5l_flush_stripe_to_raid(conf->log);
6210         if (release_inactive) {
6211                 spin_lock_irq(&conf->device_lock);
6212                 return 0;
6213         }
6214
6215         for (i = 0; i < batch_size; i++)
6216                 handle_stripe(batch[i]);
6217         log_write_stripe_run(conf);
6218
6219         cond_resched();
6220
6221         spin_lock_irq(&conf->device_lock);
6222         for (i = 0; i < batch_size; i++) {
6223                 hash = batch[i]->hash_lock_index;
6224                 __release_stripe(conf, batch[i], &temp_inactive_list[hash]);
6225         }
6226         return batch_size;
6227 }
6228
6229 static void raid5_do_work(struct work_struct *work)
6230 {
6231         struct r5worker *worker = container_of(work, struct r5worker, work);
6232         struct r5worker_group *group = worker->group;
6233         struct r5conf *conf = group->conf;
6234         struct mddev *mddev = conf->mddev;
6235         int group_id = group - conf->worker_groups;
6236         int handled;
6237         struct blk_plug plug;
6238
6239         pr_debug("+++ raid5worker active\n");
6240
6241         blk_start_plug(&plug);
6242         handled = 0;
6243         spin_lock_irq(&conf->device_lock);
6244         while (1) {
6245                 int batch_size, released;
6246
6247                 released = release_stripe_list(conf, worker->temp_inactive_list);
6248
6249                 batch_size = handle_active_stripes(conf, group_id, worker,
6250                                                    worker->temp_inactive_list);
6251                 worker->working = false;
6252                 if (!batch_size && !released)
6253                         break;
6254                 handled += batch_size;
6255                 wait_event_lock_irq(mddev->sb_wait,
6256                         !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
6257                         conf->device_lock);
6258         }
6259         pr_debug("%d stripes handled\n", handled);
6260
6261         spin_unlock_irq(&conf->device_lock);
6262
6263         flush_deferred_bios(conf);
6264
6265         r5l_flush_stripe_to_raid(conf->log);
6266
6267         async_tx_issue_pending_all();
6268         blk_finish_plug(&plug);
6269
6270         pr_debug("--- raid5worker inactive\n");
6271 }
6272
6273 /*
6274  * This is our raid5 kernel thread.
6275  *
6276  * We scan the hash table for stripes which can be handled now.
6277  * During the scan, completed stripes are saved for us by the interrupt
6278  * handler, so that they will not have to wait for our next wakeup.
6279  */
6280 static void raid5d(struct md_thread *thread)
6281 {
6282         struct mddev *mddev = thread->mddev;
6283         struct r5conf *conf = mddev->private;
6284         int handled;
6285         struct blk_plug plug;
6286
6287         pr_debug("+++ raid5d active\n");
6288
6289         md_check_recovery(mddev);
6290
6291         blk_start_plug(&plug);
6292         handled = 0;
6293         spin_lock_irq(&conf->device_lock);
6294         while (1) {
6295                 struct bio *bio;
6296                 int batch_size, released;
6297                 unsigned int offset;
6298
6299                 released = release_stripe_list(conf, conf->temp_inactive_list);
6300                 if (released)
6301                         clear_bit(R5_DID_ALLOC, &conf->cache_state);
6302
6303                 if (
6304                     !list_empty(&conf->bitmap_list)) {
6305                         /* Now is a good time to flush some bitmap updates */
6306                         conf->seq_flush++;
6307                         spin_unlock_irq(&conf->device_lock);
6308                         md_bitmap_unplug(mddev->bitmap);
6309                         spin_lock_irq(&conf->device_lock);
6310                         conf->seq_write = conf->seq_flush;
6311                         activate_bit_delay(conf, conf->temp_inactive_list);
6312                 }
6313                 raid5_activate_delayed(conf);
6314
6315                 while ((bio = remove_bio_from_retry(conf, &offset))) {
6316                         int ok;
6317                         spin_unlock_irq(&conf->device_lock);
6318                         ok = retry_aligned_read(conf, bio, offset);
6319                         spin_lock_irq(&conf->device_lock);
6320                         if (!ok)
6321                                 break;
6322                         handled++;
6323                 }
6324
6325                 batch_size = handle_active_stripes(conf, ANY_GROUP, NULL,
6326                                                    conf->temp_inactive_list);
6327                 if (!batch_size && !released)
6328                         break;
6329                 handled += batch_size;
6330
6331                 if (mddev->sb_flags & ~(1 << MD_SB_CHANGE_PENDING)) {
6332                         spin_unlock_irq(&conf->device_lock);
6333                         md_check_recovery(mddev);
6334                         spin_lock_irq(&conf->device_lock);
6335                 }
6336         }
6337         pr_debug("%d stripes handled\n", handled);
6338
6339         spin_unlock_irq(&conf->device_lock);
6340         if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state) &&
6341             mutex_trylock(&conf->cache_size_mutex)) {
6342                 grow_one_stripe(conf, __GFP_NOWARN);
6343                 /* Set flag even if allocation failed.  This helps
6344                  * slow down allocation requests when mem is short
6345                  */
6346                 set_bit(R5_DID_ALLOC, &conf->cache_state);
6347                 mutex_unlock(&conf->cache_size_mutex);
6348         }
6349
6350         flush_deferred_bios(conf);
6351
6352         r5l_flush_stripe_to_raid(conf->log);
6353
6354         async_tx_issue_pending_all();
6355         blk_finish_plug(&plug);
6356
6357         pr_debug("--- raid5d inactive\n");
6358 }
6359
6360 static ssize_t
6361 raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
6362 {
6363         struct r5conf *conf;
6364         int ret = 0;
6365         spin_lock(&mddev->lock);
6366         conf = mddev->private;
6367         if (conf)
6368                 ret = sprintf(page, "%d\n", conf->min_nr_stripes);
6369         spin_unlock(&mddev->lock);
6370         return ret;
6371 }
6372
6373 int
6374 raid5_set_cache_size(struct mddev *mddev, int size)
6375 {
6376         int result = 0;
6377         struct r5conf *conf = mddev->private;
6378
6379         if (size <= 16 || size > 32768)
6380                 return -EINVAL;
6381
6382         conf->min_nr_stripes = size;
6383         mutex_lock(&conf->cache_size_mutex);
6384         while (size < conf->max_nr_stripes &&
6385                drop_one_stripe(conf))
6386                 ;
6387         mutex_unlock(&conf->cache_size_mutex);
6388
6389         md_allow_write(mddev);
6390
6391         mutex_lock(&conf->cache_size_mutex);
6392         while (size > conf->max_nr_stripes)
6393                 if (!grow_one_stripe(conf, GFP_KERNEL)) {
6394                         conf->min_nr_stripes = conf->max_nr_stripes;
6395                         result = -ENOMEM;
6396                         break;
6397                 }
6398         mutex_unlock(&conf->cache_size_mutex);
6399
6400         return result;
6401 }
6402 EXPORT_SYMBOL(raid5_set_cache_size);
6403
6404 static ssize_t
6405 raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
6406 {
6407         struct r5conf *conf;
6408         unsigned long new;
6409         int err;
6410
6411         if (len >= PAGE_SIZE)
6412                 return -EINVAL;
6413         if (kstrtoul(page, 10, &new))
6414                 return -EINVAL;
6415         err = mddev_lock(mddev);
6416         if (err)
6417                 return err;
6418         conf = mddev->private;
6419         if (!conf)
6420                 err = -ENODEV;
6421         else
6422                 err = raid5_set_cache_size(mddev, new);
6423         mddev_unlock(mddev);
6424
6425         return err ?: len;
6426 }
6427
6428 static struct md_sysfs_entry
6429 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
6430                                 raid5_show_stripe_cache_size,
6431                                 raid5_store_stripe_cache_size);
6432
6433 static ssize_t
6434 raid5_show_rmw_level(struct mddev  *mddev, char *page)
6435 {
6436         struct r5conf *conf = mddev->private;
6437         if (conf)
6438                 return sprintf(page, "%d\n", conf->rmw_level);
6439         else
6440                 return 0;
6441 }
6442
6443 static ssize_t
6444 raid5_store_rmw_level(struct mddev  *mddev, const char *page, size_t len)
6445 {
6446         struct r5conf *conf = mddev->private;
6447         unsigned long new;
6448
6449         if (!conf)
6450                 return -ENODEV;
6451
6452         if (len >= PAGE_SIZE)
6453                 return -EINVAL;
6454
6455         if (kstrtoul(page, 10, &new))
6456                 return -EINVAL;
6457
6458         if (new != PARITY_DISABLE_RMW && !raid6_call.xor_syndrome)
6459                 return -EINVAL;
6460
6461         if (new != PARITY_DISABLE_RMW &&
6462             new != PARITY_ENABLE_RMW &&
6463             new != PARITY_PREFER_RMW)
6464                 return -EINVAL;
6465
6466         conf->rmw_level = new;
6467         return len;
6468 }
6469
6470 static struct md_sysfs_entry
6471 raid5_rmw_level = __ATTR(rmw_level, S_IRUGO | S_IWUSR,
6472                          raid5_show_rmw_level,
6473                          raid5_store_rmw_level);
6474
6475
6476 static ssize_t
6477 raid5_show_preread_threshold(struct mddev *mddev, char *page)
6478 {
6479         struct r5conf *conf;
6480         int ret = 0;
6481         spin_lock(&mddev->lock);
6482         conf = mddev->private;
6483         if (conf)
6484                 ret = sprintf(page, "%d\n", conf->bypass_threshold);
6485         spin_unlock(&mddev->lock);
6486         return ret;
6487 }
6488
6489 static ssize_t
6490 raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
6491 {
6492         struct r5conf *conf;
6493         unsigned long new;
6494         int err;
6495
6496         if (len >= PAGE_SIZE)
6497                 return -EINVAL;
6498         if (kstrtoul(page, 10, &new))
6499                 return -EINVAL;
6500
6501         err = mddev_lock(mddev);
6502         if (err)
6503                 return err;
6504         conf = mddev->private;
6505         if (!conf)
6506                 err = -ENODEV;
6507         else if (new > conf->min_nr_stripes)
6508                 err = -EINVAL;
6509         else
6510                 conf->bypass_threshold = new;
6511         mddev_unlock(mddev);
6512         return err ?: len;
6513 }
6514
6515 static struct md_sysfs_entry
6516 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
6517                                         S_IRUGO | S_IWUSR,
6518                                         raid5_show_preread_threshold,
6519                                         raid5_store_preread_threshold);
6520
6521 static ssize_t
6522 raid5_show_skip_copy(struct mddev *mddev, char *page)
6523 {
6524         struct r5conf *conf;
6525         int ret = 0;
6526         spin_lock(&mddev->lock);
6527         conf = mddev->private;
6528         if (conf)
6529                 ret = sprintf(page, "%d\n", conf->skip_copy);
6530         spin_unlock(&mddev->lock);
6531         return ret;
6532 }
6533
6534 static ssize_t
6535 raid5_store_skip_copy(struct mddev *mddev, const char *page, size_t len)
6536 {
6537         struct r5conf *conf;
6538         unsigned long new;
6539         int err;
6540
6541         if (len >= PAGE_SIZE)
6542                 return -EINVAL;
6543         if (kstrtoul(page, 10, &new))
6544                 return -EINVAL;
6545         new = !!new;
6546
6547         err = mddev_lock(mddev);
6548         if (err)
6549                 return err;
6550         conf = mddev->private;
6551         if (!conf)
6552                 err = -ENODEV;
6553         else if (new != conf->skip_copy) {
6554                 mddev_suspend(mddev);
6555                 conf->skip_copy = new;
6556                 if (new)
6557                         mddev->queue->backing_dev_info->capabilities |=
6558                                 BDI_CAP_STABLE_WRITES;
6559                 else
6560                         mddev->queue->backing_dev_info->capabilities &=
6561                                 ~BDI_CAP_STABLE_WRITES;
6562                 mddev_resume(mddev);
6563         }
6564         mddev_unlock(mddev);
6565         return err ?: len;
6566 }
6567
6568 static struct md_sysfs_entry
6569 raid5_skip_copy = __ATTR(skip_copy, S_IRUGO | S_IWUSR,
6570                                         raid5_show_skip_copy,
6571                                         raid5_store_skip_copy);
6572
6573 static ssize_t
6574 stripe_cache_active_show(struct mddev *mddev, char *page)
6575 {
6576         struct r5conf *conf = mddev->private;
6577         if (conf)
6578                 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
6579         else
6580                 return 0;
6581 }
6582
6583 static struct md_sysfs_entry
6584 raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
6585
6586 static ssize_t
6587 raid5_show_group_thread_cnt(struct mddev *mddev, char *page)
6588 {
6589         struct r5conf *conf;
6590         int ret = 0;
6591         spin_lock(&mddev->lock);
6592         conf = mddev->private;
6593         if (conf)
6594                 ret = sprintf(page, "%d\n", conf->worker_cnt_per_group);
6595         spin_unlock(&mddev->lock);
6596         return ret;
6597 }
6598
6599 static int alloc_thread_groups(struct r5conf *conf, int cnt,
6600                                int *group_cnt,
6601                                int *worker_cnt_per_group,
6602                                struct r5worker_group **worker_groups);
6603 static ssize_t
6604 raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
6605 {
6606         struct r5conf *conf;
6607         unsigned int new;
6608         int err;
6609         struct r5worker_group *new_groups, *old_groups;
6610         int group_cnt, worker_cnt_per_group;
6611
6612         if (len >= PAGE_SIZE)
6613                 return -EINVAL;
6614         if (kstrtouint(page, 10, &new))
6615                 return -EINVAL;
6616         /* 8192 should be big enough */
6617         if (new > 8192)
6618                 return -EINVAL;
6619
6620         err = mddev_lock(mddev);
6621         if (err)
6622                 return err;
6623         conf = mddev->private;
6624         if (!conf)
6625                 err = -ENODEV;
6626         else if (new != conf->worker_cnt_per_group) {
6627                 mddev_suspend(mddev);
6628
6629                 old_groups = conf->worker_groups;
6630                 if (old_groups)
6631                         flush_workqueue(raid5_wq);
6632
6633                 err = alloc_thread_groups(conf, new,
6634                                           &group_cnt, &worker_cnt_per_group,
6635                                           &new_groups);
6636                 if (!err) {
6637                         spin_lock_irq(&conf->device_lock);
6638                         conf->group_cnt = group_cnt;
6639                         conf->worker_cnt_per_group = worker_cnt_per_group;
6640                         conf->worker_groups = new_groups;
6641                         spin_unlock_irq(&conf->device_lock);
6642
6643                         if (old_groups)
6644                                 kfree(old_groups[0].workers);
6645                         kfree(old_groups);
6646                 }
6647                 mddev_resume(mddev);
6648         }
6649         mddev_unlock(mddev);
6650
6651         return err ?: len;
6652 }
6653
6654 static struct md_sysfs_entry
6655 raid5_group_thread_cnt = __ATTR(group_thread_cnt, S_IRUGO | S_IWUSR,
6656                                 raid5_show_group_thread_cnt,
6657                                 raid5_store_group_thread_cnt);
6658
6659 static struct attribute *raid5_attrs[] =  {
6660         &raid5_stripecache_size.attr,
6661         &raid5_stripecache_active.attr,
6662         &raid5_preread_bypass_threshold.attr,
6663         &raid5_group_thread_cnt.attr,
6664         &raid5_skip_copy.attr,
6665         &raid5_rmw_level.attr,
6666         &r5c_journal_mode.attr,
6667         &ppl_write_hint.attr,
6668         NULL,
6669 };
6670 static struct attribute_group raid5_attrs_group = {
6671         .name = NULL,
6672         .attrs = raid5_attrs,
6673 };
6674
6675 static int alloc_thread_groups(struct r5conf *conf, int cnt,
6676                                int *group_cnt,
6677                                int *worker_cnt_per_group,
6678                                struct r5worker_group **worker_groups)
6679 {
6680         int i, j, k;
6681         ssize_t size;
6682         struct r5worker *workers;
6683
6684         *worker_cnt_per_group = cnt;
6685         if (cnt == 0) {
6686                 *group_cnt = 0;
6687                 *worker_groups = NULL;
6688                 return 0;
6689         }
6690         *group_cnt = num_possible_nodes();
6691         size = sizeof(struct r5worker) * cnt;
6692         workers = kcalloc(size, *group_cnt, GFP_NOIO);
6693         *worker_groups = kcalloc(*group_cnt, sizeof(struct r5worker_group),
6694                                  GFP_NOIO);
6695         if (!*worker_groups || !workers) {
6696                 kfree(workers);
6697                 kfree(*worker_groups);
6698                 return -ENOMEM;
6699         }
6700
6701         for (i = 0; i < *group_cnt; i++) {
6702                 struct r5worker_group *group;
6703
6704                 group = &(*worker_groups)[i];
6705                 INIT_LIST_HEAD(&group->handle_list);
6706                 INIT_LIST_HEAD(&group->loprio_list);
6707                 group->conf = conf;
6708                 group->workers = workers + i * cnt;
6709
6710                 for (j = 0; j < cnt; j++) {
6711                         struct r5worker *worker = group->workers + j;
6712                         worker->group = group;
6713                         INIT_WORK(&worker->work, raid5_do_work);
6714
6715                         for (k = 0; k < NR_STRIPE_HASH_LOCKS; k++)
6716                                 INIT_LIST_HEAD(worker->temp_inactive_list + k);
6717                 }
6718         }
6719
6720         return 0;
6721 }
6722
6723 static void free_thread_groups(struct r5conf *conf)
6724 {
6725         if (conf->worker_groups)
6726                 kfree(conf->worker_groups[0].workers);
6727         kfree(conf->worker_groups);
6728         conf->worker_groups = NULL;
6729 }
6730
6731 static sector_t
6732 raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
6733 {
6734         struct r5conf *conf = mddev->private;
6735
6736         if (!sectors)
6737                 sectors = mddev->dev_sectors;
6738         if (!raid_disks)
6739                 /* size is defined by the smallest of previous and new size */
6740                 raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
6741
6742         sectors &= ~((sector_t)conf->chunk_sectors - 1);
6743         sectors &= ~((sector_t)conf->prev_chunk_sectors - 1);
6744         return sectors * (raid_disks - conf->max_degraded);
6745 }
6746
6747 static void free_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6748 {
6749         safe_put_page(percpu->spare_page);
6750         percpu->spare_page = NULL;
6751         kvfree(percpu->scribble);
6752         percpu->scribble = NULL;
6753 }
6754
6755 static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6756 {
6757         if (conf->level == 6 && !percpu->spare_page) {
6758                 percpu->spare_page = alloc_page(GFP_KERNEL);
6759                 if (!percpu->spare_page)
6760                         return -ENOMEM;
6761         }
6762
6763         if (scribble_alloc(percpu,
6764                            max(conf->raid_disks,
6765                                conf->previous_raid_disks),
6766                            max(conf->chunk_sectors,
6767                                conf->prev_chunk_sectors)
6768                            / STRIPE_SECTORS,
6769                            GFP_KERNEL)) {
6770                 free_scratch_buffer(conf, percpu);
6771                 return -ENOMEM;
6772         }
6773
6774         return 0;
6775 }
6776
6777 static int raid456_cpu_dead(unsigned int cpu, struct hlist_node *node)
6778 {
6779         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
6780
6781         free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));
6782         return 0;
6783 }
6784
6785 static void raid5_free_percpu(struct r5conf *conf)
6786 {
6787         if (!conf->percpu)
6788                 return;
6789
6790         cpuhp_state_remove_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
6791         free_percpu(conf->percpu);
6792 }
6793
6794 static void free_conf(struct r5conf *conf)
6795 {
6796         int i;
6797
6798         log_exit(conf);
6799
6800         unregister_shrinker(&conf->shrinker);
6801         free_thread_groups(conf);
6802         shrink_stripes(conf);
6803         raid5_free_percpu(conf);
6804         for (i = 0; i < conf->pool_size; i++)
6805                 if (conf->disks[i].extra_page)
6806                         put_page(conf->disks[i].extra_page);
6807         kfree(conf->disks);
6808         bioset_exit(&conf->bio_split);
6809         kfree(conf->stripe_hashtbl);
6810         kfree(conf->pending_data);
6811         kfree(conf);
6812 }
6813
6814 static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
6815 {
6816         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
6817         struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);
6818
6819         if (alloc_scratch_buffer(conf, percpu)) {
6820                 pr_warn("%s: failed memory allocation for cpu%u\n",
6821                         __func__, cpu);
6822                 return -ENOMEM;
6823         }
6824         return 0;
6825 }
6826
6827 static int raid5_alloc_percpu(struct r5conf *conf)
6828 {
6829         int err = 0;
6830
6831         conf->percpu = alloc_percpu(struct raid5_percpu);
6832         if (!conf->percpu)
6833                 return -ENOMEM;
6834
6835         err = cpuhp_state_add_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
6836         if (!err) {
6837                 conf->scribble_disks = max(conf->raid_disks,
6838                         conf->previous_raid_disks);
6839                 conf->scribble_sectors = max(conf->chunk_sectors,
6840                         conf->prev_chunk_sectors);
6841         }
6842         return err;
6843 }
6844
6845 static unsigned long raid5_cache_scan(struct shrinker *shrink,
6846                                       struct shrink_control *sc)
6847 {
6848         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6849         unsigned long ret = SHRINK_STOP;
6850
6851         if (mutex_trylock(&conf->cache_size_mutex)) {
6852                 ret= 0;
6853                 while (ret < sc->nr_to_scan &&
6854                        conf->max_nr_stripes > conf->min_nr_stripes) {
6855                         if (drop_one_stripe(conf) == 0) {
6856                                 ret = SHRINK_STOP;
6857                                 break;
6858                         }
6859                         ret++;
6860                 }
6861                 mutex_unlock(&conf->cache_size_mutex);
6862         }
6863         return ret;
6864 }
6865
6866 static unsigned long raid5_cache_count(struct shrinker *shrink,
6867                                        struct shrink_control *sc)
6868 {
6869         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6870
6871         if (conf->max_nr_stripes < conf->min_nr_stripes)
6872                 /* unlikely, but not impossible */
6873                 return 0;
6874         return conf->max_nr_stripes - conf->min_nr_stripes;
6875 }
6876
6877 static struct r5conf *setup_conf(struct mddev *mddev)
6878 {
6879         struct r5conf *conf;
6880         int raid_disk, memory, max_disks;
6881         struct md_rdev *rdev;
6882         struct disk_info *disk;
6883         char pers_name[6];
6884         int i;
6885         int group_cnt, worker_cnt_per_group;
6886         struct r5worker_group *new_group;
6887         int ret;
6888
6889         if (mddev->new_level != 5
6890             && mddev->new_level != 4
6891             && mddev->new_level != 6) {
6892                 pr_warn("md/raid:%s: raid level not set to 4/5/6 (%d)\n",
6893                         mdname(mddev), mddev->new_level);
6894                 return ERR_PTR(-EIO);
6895         }
6896         if ((mddev->new_level == 5
6897              && !algorithm_valid_raid5(mddev->new_layout)) ||
6898             (mddev->new_level == 6
6899              && !algorithm_valid_raid6(mddev->new_layout))) {
6900                 pr_warn("md/raid:%s: layout %d not supported\n",
6901                         mdname(mddev), mddev->new_layout);
6902                 return ERR_PTR(-EIO);
6903         }
6904         if (mddev->new_level == 6 && mddev->raid_disks < 4) {
6905                 pr_warn("md/raid:%s: not enough configured devices (%d, minimum 4)\n",
6906                         mdname(mddev), mddev->raid_disks);
6907                 return ERR_PTR(-EINVAL);
6908         }
6909
6910         if (!mddev->new_chunk_sectors ||
6911             (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
6912             !is_power_of_2(mddev->new_chunk_sectors)) {
6913                 pr_warn("md/raid:%s: invalid chunk size %d\n",
6914                         mdname(mddev), mddev->new_chunk_sectors << 9);
6915                 return ERR_PTR(-EINVAL);
6916         }
6917
6918         conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
6919         if (conf == NULL)
6920                 goto abort;
6921         INIT_LIST_HEAD(&conf->free_list);
6922         INIT_LIST_HEAD(&conf->pending_list);
6923         conf->pending_data = kcalloc(PENDING_IO_MAX,
6924                                      sizeof(struct r5pending_data),
6925                                      GFP_KERNEL);
6926         if (!conf->pending_data)
6927                 goto abort;
6928         for (i = 0; i < PENDING_IO_MAX; i++)
6929                 list_add(&conf->pending_data[i].sibling, &conf->free_list);
6930         /* Don't enable multi-threading by default*/
6931         if (!alloc_thread_groups(conf, 0, &group_cnt, &worker_cnt_per_group,
6932                                  &new_group)) {
6933                 conf->group_cnt = group_cnt;
6934                 conf->worker_cnt_per_group = worker_cnt_per_group;
6935                 conf->worker_groups = new_group;
6936         } else
6937                 goto abort;
6938         spin_lock_init(&conf->device_lock);
6939         seqcount_init(&conf->gen_lock);
6940         mutex_init(&conf->cache_size_mutex);
6941         init_waitqueue_head(&conf->wait_for_quiescent);
6942         init_waitqueue_head(&conf->wait_for_stripe);
6943         init_waitqueue_head(&conf->wait_for_overlap);
6944         INIT_LIST_HEAD(&conf->handle_list);
6945         INIT_LIST_HEAD(&conf->loprio_list);
6946         INIT_LIST_HEAD(&conf->hold_list);
6947         INIT_LIST_HEAD(&conf->delayed_list);
6948         INIT_LIST_HEAD(&conf->bitmap_list);
6949         init_llist_head(&conf->released_stripes);
6950         atomic_set(&conf->active_stripes, 0);
6951         atomic_set(&conf->preread_active_stripes, 0);
6952         atomic_set(&conf->active_aligned_reads, 0);
6953         spin_lock_init(&conf->pending_bios_lock);
6954         conf->batch_bio_dispatch = true;
6955         rdev_for_each(rdev, mddev) {
6956                 if (test_bit(Journal, &rdev->flags))
6957                         continue;
6958                 if (blk_queue_nonrot(bdev_get_queue(rdev->bdev))) {
6959                         conf->batch_bio_dispatch = false;
6960                         break;
6961                 }
6962         }
6963
6964         conf->bypass_threshold = BYPASS_THRESHOLD;
6965         conf->recovery_disabled = mddev->recovery_disabled - 1;
6966
6967         conf->raid_disks = mddev->raid_disks;
6968         if (mddev->reshape_position == MaxSector)
6969                 conf->previous_raid_disks = mddev->raid_disks;
6970         else
6971                 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
6972         max_disks = max(conf->raid_disks, conf->previous_raid_disks);
6973
6974         conf->disks = kcalloc(max_disks, sizeof(struct disk_info),
6975                               GFP_KERNEL);
6976
6977         if (!conf->disks)
6978                 goto abort;
6979
6980         for (i = 0; i < max_disks; i++) {
6981                 conf->disks[i].extra_page = alloc_page(GFP_KERNEL);
6982                 if (!conf->disks[i].extra_page)
6983                         goto abort;
6984         }
6985
6986         ret = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
6987         if (ret)
6988                 goto abort;
6989         conf->mddev = mddev;
6990
6991         if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
6992                 goto abort;
6993
6994         /* We init hash_locks[0] separately to that it can be used
6995          * as the reference lock in the spin_lock_nest_lock() call
6996          * in lock_all_device_hash_locks_irq in order to convince
6997          * lockdep that we know what we are doing.
6998          */
6999         spin_lock_init(conf->hash_locks);
7000         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
7001                 spin_lock_init(conf->hash_locks + i);
7002
7003         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
7004                 INIT_LIST_HEAD(conf->inactive_list + i);
7005
7006         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
7007                 INIT_LIST_HEAD(conf->temp_inactive_list + i);
7008
7009         atomic_set(&conf->r5c_cached_full_stripes, 0);
7010         INIT_LIST_HEAD(&conf->r5c_full_stripe_list);
7011         atomic_set(&conf->r5c_cached_partial_stripes, 0);
7012         INIT_LIST_HEAD(&conf->r5c_partial_stripe_list);
7013         atomic_set(&conf->r5c_flushing_full_stripes, 0);
7014         atomic_set(&conf->r5c_flushing_partial_stripes, 0);
7015
7016         conf->level = mddev->new_level;
7017         conf->chunk_sectors = mddev->new_chunk_sectors;
7018         if (raid5_alloc_percpu(conf) != 0)
7019                 goto abort;
7020
7021         pr_debug("raid456: run(%s) called.\n", mdname(mddev));
7022
7023         rdev_for_each(rdev, mddev) {
7024                 raid_disk = rdev->raid_disk;
7025                 if (raid_disk >= max_disks
7026                     || raid_disk < 0 || test_bit(Journal, &rdev->flags))
7027                         continue;
7028                 disk = conf->disks + raid_disk;
7029
7030                 if (test_bit(Replacement, &rdev->flags)) {
7031                         if (disk->replacement)
7032                                 goto abort;
7033                         disk->replacement = rdev;
7034                 } else {
7035                         if (disk->rdev)
7036                                 goto abort;
7037                         disk->rdev = rdev;
7038                 }
7039
7040                 if (test_bit(In_sync, &rdev->flags)) {
7041                         char b[BDEVNAME_SIZE];
7042                         pr_info("md/raid:%s: device %s operational as raid disk %d\n",
7043                                 mdname(mddev), bdevname(rdev->bdev, b), raid_disk);
7044                 } else if (rdev->saved_raid_disk != raid_disk)
7045                         /* Cannot rely on bitmap to complete recovery */
7046                         conf->fullsync = 1;
7047         }
7048
7049         conf->level = mddev->new_level;
7050         if (conf->level == 6) {
7051                 conf->max_degraded = 2;
7052                 if (raid6_call.xor_syndrome)
7053                         conf->rmw_level = PARITY_ENABLE_RMW;
7054                 else
7055                         conf->rmw_level = PARITY_DISABLE_RMW;
7056         } else {
7057                 conf->max_degraded = 1;
7058                 conf->rmw_level = PARITY_ENABLE_RMW;
7059         }
7060         conf->algorithm = mddev->new_layout;
7061         conf->reshape_progress = mddev->reshape_position;
7062         if (conf->reshape_progress != MaxSector) {
7063                 conf->prev_chunk_sectors = mddev->chunk_sectors;
7064                 conf->prev_algo = mddev->layout;
7065         } else {
7066                 conf->prev_chunk_sectors = conf->chunk_sectors;
7067                 conf->prev_algo = conf->algorithm;
7068         }
7069
7070         conf->min_nr_stripes = NR_STRIPES;
7071         if (mddev->reshape_position != MaxSector) {
7072                 int stripes = max_t(int,
7073                         ((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4,
7074                         ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4);
7075                 conf->min_nr_stripes = max(NR_STRIPES, stripes);
7076                 if (conf->min_nr_stripes != NR_STRIPES)
7077                         pr_info("md/raid:%s: force stripe size %d for reshape\n",
7078                                 mdname(mddev), conf->min_nr_stripes);
7079         }
7080         memory = conf->min_nr_stripes * (sizeof(struct stripe_head) +
7081                  max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
7082         atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS);
7083         if (grow_stripes(conf, conf->min_nr_stripes)) {
7084                 pr_warn("md/raid:%s: couldn't allocate %dkB for buffers\n",
7085                         mdname(mddev), memory);
7086                 goto abort;
7087         } else
7088                 pr_debug("md/raid:%s: allocated %dkB\n", mdname(mddev), memory);
7089         /*
7090          * Losing a stripe head costs more than the time to refill it,
7091          * it reduces the queue depth and so can hurt throughput.
7092          * So set it rather large, scaled by number of devices.
7093          */
7094         conf->shrinker.seeks = DEFAULT_SEEKS * conf->raid_disks * 4;
7095         conf->shrinker.scan_objects = raid5_cache_scan;
7096         conf->shrinker.count_objects = raid5_cache_count;
7097         conf->shrinker.batch = 128;
7098         conf->shrinker.flags = 0;
7099         if (register_shrinker(&conf->shrinker)) {
7100                 pr_warn("md/raid:%s: couldn't register shrinker.\n",
7101                         mdname(mddev));
7102                 goto abort;
7103         }
7104
7105         sprintf(pers_name, "raid%d", mddev->new_level);
7106         conf->thread = md_register_thread(raid5d, mddev, pers_name);
7107         if (!conf->thread) {
7108                 pr_warn("md/raid:%s: couldn't allocate thread.\n",
7109                         mdname(mddev));
7110                 goto abort;
7111         }
7112
7113         return conf;
7114
7115  abort:
7116         if (conf) {
7117                 free_conf(conf);
7118                 return ERR_PTR(-EIO);
7119         } else
7120                 return ERR_PTR(-ENOMEM);
7121 }
7122
7123 static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
7124 {
7125         switch (algo) {
7126         case ALGORITHM_PARITY_0:
7127                 if (raid_disk < max_degraded)
7128                         return 1;
7129                 break;
7130         case ALGORITHM_PARITY_N:
7131                 if (raid_disk >= raid_disks - max_degraded)
7132                         return 1;
7133                 break;
7134         case ALGORITHM_PARITY_0_6:
7135                 if (raid_disk == 0 ||
7136                     raid_disk == raid_disks - 1)
7137                         return 1;
7138                 break;
7139         case ALGORITHM_LEFT_ASYMMETRIC_6:
7140         case ALGORITHM_RIGHT_ASYMMETRIC_6:
7141         case ALGORITHM_LEFT_SYMMETRIC_6:
7142         case ALGORITHM_RIGHT_SYMMETRIC_6:
7143                 if (raid_disk == raid_disks - 1)
7144                         return 1;
7145         }
7146         return 0;
7147 }
7148
7149 static int raid5_run(struct mddev *mddev)
7150 {
7151         struct r5conf *conf;
7152         int working_disks = 0;
7153         int dirty_parity_disks = 0;
7154         struct md_rdev *rdev;
7155         struct md_rdev *journal_dev = NULL;
7156         sector_t reshape_offset = 0;
7157         int i;
7158         long long min_offset_diff = 0;
7159         int first = 1;
7160
7161         if (mddev_init_writes_pending(mddev) < 0)
7162                 return -ENOMEM;
7163
7164         if (mddev->recovery_cp != MaxSector)
7165                 pr_notice("md/raid:%s: not clean -- starting background reconstruction\n",
7166                           mdname(mddev));
7167
7168         rdev_for_each(rdev, mddev) {
7169                 long long diff;
7170
7171                 if (test_bit(Journal, &rdev->flags)) {
7172                         journal_dev = rdev;
7173                         continue;
7174                 }
7175                 if (rdev->raid_disk < 0)
7176                         continue;
7177                 diff = (rdev->new_data_offset - rdev->data_offset);
7178                 if (first) {
7179                         min_offset_diff = diff;
7180                         first = 0;
7181                 } else if (mddev->reshape_backwards &&
7182                          diff < min_offset_diff)
7183                         min_offset_diff = diff;
7184                 else if (!mddev->reshape_backwards &&
7185                          diff > min_offset_diff)
7186                         min_offset_diff = diff;
7187         }
7188
7189         if ((test_bit(MD_HAS_JOURNAL, &mddev->flags) || journal_dev) &&
7190             (mddev->bitmap_info.offset || mddev->bitmap_info.file)) {
7191                 pr_notice("md/raid:%s: array cannot have both journal and bitmap\n",
7192                           mdname(mddev));
7193                 return -EINVAL;
7194         }
7195
7196         if (mddev->reshape_position != MaxSector) {
7197                 /* Check that we can continue the reshape.
7198                  * Difficulties arise if the stripe we would write to
7199                  * next is at or after the stripe we would read from next.
7200                  * For a reshape that changes the number of devices, this
7201                  * is only possible for a very short time, and mdadm makes
7202                  * sure that time appears to have past before assembling
7203                  * the array.  So we fail if that time hasn't passed.
7204                  * For a reshape that keeps the number of devices the same
7205                  * mdadm must be monitoring the reshape can keeping the
7206                  * critical areas read-only and backed up.  It will start
7207                  * the array in read-only mode, so we check for that.
7208                  */
7209                 sector_t here_new, here_old;
7210                 int old_disks;
7211                 int max_degraded = (mddev->level == 6 ? 2 : 1);
7212                 int chunk_sectors;
7213                 int new_data_disks;
7214
7215                 if (journal_dev) {
7216                         pr_warn("md/raid:%s: don't support reshape with journal - aborting.\n",
7217                                 mdname(mddev));
7218                         return -EINVAL;
7219                 }
7220
7221                 if (mddev->new_level != mddev->level) {
7222                         pr_warn("md/raid:%s: unsupported reshape required - aborting.\n",
7223                                 mdname(mddev));
7224                         return -EINVAL;
7225                 }
7226                 old_disks = mddev->raid_disks - mddev->delta_disks;
7227                 /* reshape_position must be on a new-stripe boundary, and one
7228                  * further up in new geometry must map after here in old
7229                  * geometry.
7230                  * If the chunk sizes are different, then as we perform reshape
7231                  * in units of the largest of the two, reshape_position needs
7232                  * be a multiple of the largest chunk size times new data disks.
7233                  */
7234                 here_new = mddev->reshape_position;
7235                 chunk_sectors = max(mddev->chunk_sectors, mddev->new_chunk_sectors);
7236                 new_data_disks = mddev->raid_disks - max_degraded;
7237                 if (sector_div(here_new, chunk_sectors * new_data_disks)) {
7238                         pr_warn("md/raid:%s: reshape_position not on a stripe boundary\n",
7239                                 mdname(mddev));
7240                         return -EINVAL;
7241                 }
7242                 reshape_offset = here_new * chunk_sectors;
7243                 /* here_new is the stripe we will write to */
7244                 here_old = mddev->reshape_position;
7245                 sector_div(here_old, chunk_sectors * (old_disks-max_degraded));
7246                 /* here_old is the first stripe that we might need to read
7247                  * from */
7248                 if (mddev->delta_disks == 0) {
7249                         /* We cannot be sure it is safe to start an in-place
7250                          * reshape.  It is only safe if user-space is monitoring
7251                          * and taking constant backups.
7252                          * mdadm always starts a situation like this in
7253                          * readonly mode so it can take control before
7254                          * allowing any writes.  So just check for that.
7255                          */
7256                         if (abs(min_offset_diff) >= mddev->chunk_sectors &&
7257                             abs(min_offset_diff) >= mddev->new_chunk_sectors)
7258                                 /* not really in-place - so OK */;
7259                         else if (mddev->ro == 0) {
7260                                 pr_warn("md/raid:%s: in-place reshape must be started in read-only mode - aborting\n",
7261                                         mdname(mddev));
7262                                 return -EINVAL;
7263                         }
7264                 } else if (mddev->reshape_backwards
7265                     ? (here_new * chunk_sectors + min_offset_diff <=
7266                        here_old * chunk_sectors)
7267                     : (here_new * chunk_sectors >=
7268                        here_old * chunk_sectors + (-min_offset_diff))) {
7269                         /* Reading from the same stripe as writing to - bad */
7270                         pr_warn("md/raid:%s: reshape_position too early for auto-recovery - aborting.\n",
7271                                 mdname(mddev));
7272                         return -EINVAL;
7273                 }
7274                 pr_debug("md/raid:%s: reshape will continue\n", mdname(mddev));
7275                 /* OK, we should be able to continue; */
7276         } else {
7277                 BUG_ON(mddev->level != mddev->new_level);
7278                 BUG_ON(mddev->layout != mddev->new_layout);
7279                 BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
7280                 BUG_ON(mddev->delta_disks != 0);
7281         }
7282
7283         if (test_bit(MD_HAS_JOURNAL, &mddev->flags) &&
7284             test_bit(MD_HAS_PPL, &mddev->flags)) {
7285                 pr_warn("md/raid:%s: using journal device and PPL not allowed - disabling PPL\n",
7286                         mdname(mddev));
7287                 clear_bit(MD_HAS_PPL, &mddev->flags);
7288                 clear_bit(MD_HAS_MULTIPLE_PPLS, &mddev->flags);
7289         }
7290
7291         if (mddev->private == NULL)
7292                 conf = setup_conf(mddev);
7293         else
7294                 conf = mddev->private;
7295
7296         if (IS_ERR(conf))
7297                 return PTR_ERR(conf);
7298
7299         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
7300                 if (!journal_dev) {
7301                         pr_warn("md/raid:%s: journal disk is missing, force array readonly\n",
7302                                 mdname(mddev));
7303                         mddev->ro = 1;
7304                         set_disk_ro(mddev->gendisk, 1);
7305                 } else if (mddev->recovery_cp == MaxSector)
7306                         set_bit(MD_JOURNAL_CLEAN, &mddev->flags);
7307         }
7308
7309         conf->min_offset_diff = min_offset_diff;
7310         mddev->thread = conf->thread;
7311         conf->thread = NULL;
7312         mddev->private = conf;
7313
7314         for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
7315              i++) {
7316                 rdev = conf->disks[i].rdev;
7317                 if (!rdev && conf->disks[i].replacement) {
7318                         /* The replacement is all we have yet */
7319                         rdev = conf->disks[i].replacement;
7320                         conf->disks[i].replacement = NULL;
7321                         clear_bit(Replacement, &rdev->flags);
7322                         conf->disks[i].rdev = rdev;
7323                 }
7324                 if (!rdev)
7325                         continue;
7326                 if (conf->disks[i].replacement &&
7327                     conf->reshape_progress != MaxSector) {
7328                         /* replacements and reshape simply do not mix. */
7329                         pr_warn("md: cannot handle concurrent replacement and reshape.\n");
7330                         goto abort;
7331                 }
7332                 if (test_bit(In_sync, &rdev->flags)) {
7333                         working_disks++;
7334                         continue;
7335                 }
7336                 /* This disc is not fully in-sync.  However if it
7337                  * just stored parity (beyond the recovery_offset),
7338                  * when we don't need to be concerned about the
7339                  * array being dirty.
7340                  * When reshape goes 'backwards', we never have
7341                  * partially completed devices, so we only need
7342                  * to worry about reshape going forwards.
7343                  */
7344                 /* Hack because v0.91 doesn't store recovery_offset properly. */
7345                 if (mddev->major_version == 0 &&
7346                     mddev->minor_version > 90)
7347                         rdev->recovery_offset = reshape_offset;
7348
7349                 if (rdev->recovery_offset < reshape_offset) {
7350                         /* We need to check old and new layout */
7351                         if (!only_parity(rdev->raid_disk,
7352                                          conf->algorithm,
7353                                          conf->raid_disks,
7354                                          conf->max_degraded))
7355                                 continue;
7356                 }
7357                 if (!only_parity(rdev->raid_disk,
7358                                  conf->prev_algo,
7359                                  conf->previous_raid_disks,
7360                                  conf->max_degraded))
7361                         continue;
7362                 dirty_parity_disks++;
7363         }
7364
7365         /*
7366          * 0 for a fully functional array, 1 or 2 for a degraded array.
7367          */
7368         mddev->degraded = raid5_calc_degraded(conf);
7369
7370         if (has_failed(conf)) {
7371                 pr_crit("md/raid:%s: not enough operational devices (%d/%d failed)\n",
7372                         mdname(mddev), mddev->degraded, conf->raid_disks);
7373                 goto abort;
7374         }
7375
7376         /* device size must be a multiple of chunk size */
7377         mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
7378         mddev->resync_max_sectors = mddev->dev_sectors;
7379
7380         if (mddev->degraded > dirty_parity_disks &&
7381             mddev->recovery_cp != MaxSector) {
7382                 if (test_bit(MD_HAS_PPL, &mddev->flags))
7383                         pr_crit("md/raid:%s: starting dirty degraded array with PPL.\n",
7384                                 mdname(mddev));
7385                 else if (mddev->ok_start_degraded)
7386                         pr_crit("md/raid:%s: starting dirty degraded array - data corruption possible.\n",
7387                                 mdname(mddev));
7388                 else {
7389                         pr_crit("md/raid:%s: cannot start dirty degraded array.\n",
7390                                 mdname(mddev));
7391                         goto abort;
7392                 }
7393         }
7394
7395         pr_info("md/raid:%s: raid level %d active with %d out of %d devices, algorithm %d\n",
7396                 mdname(mddev), conf->level,
7397                 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
7398                 mddev->new_layout);
7399
7400         print_raid5_conf(conf);
7401
7402         if (conf->reshape_progress != MaxSector) {
7403                 conf->reshape_safe = conf->reshape_progress;
7404                 atomic_set(&conf->reshape_stripes, 0);
7405                 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7406                 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7407                 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7408                 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7409                 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7410                                                         "reshape");
7411                 if (!mddev->sync_thread)
7412                         goto abort;
7413         }
7414
7415         /* Ok, everything is just fine now */
7416         if (mddev->to_remove == &raid5_attrs_group)
7417                 mddev->to_remove = NULL;
7418         else if (mddev->kobj.sd &&
7419             sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
7420                 pr_warn("raid5: failed to create sysfs attributes for %s\n",
7421                         mdname(mddev));
7422         md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
7423
7424         if (mddev->queue) {
7425                 int chunk_size;
7426                 /* read-ahead size must cover two whole stripes, which
7427                  * is 2 * (datadisks) * chunksize where 'n' is the
7428                  * number of raid devices
7429                  */
7430                 int data_disks = conf->previous_raid_disks - conf->max_degraded;
7431                 int stripe = data_disks *
7432                         ((mddev->chunk_sectors << 9) / PAGE_SIZE);
7433                 if (mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
7434                         mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
7435
7436                 chunk_size = mddev->chunk_sectors << 9;
7437                 blk_queue_io_min(mddev->queue, chunk_size);
7438                 blk_queue_io_opt(mddev->queue, chunk_size *
7439                                  (conf->raid_disks - conf->max_degraded));
7440                 mddev->queue->limits.raid_partial_stripes_expensive = 1;
7441                 /*
7442                  * We can only discard a whole stripe. It doesn't make sense to
7443                  * discard data disk but write parity disk
7444                  */
7445                 stripe = stripe * PAGE_SIZE;
7446                 /* Round up to power of 2, as discard handling
7447                  * currently assumes that */
7448                 while ((stripe-1) & stripe)
7449                         stripe = (stripe | (stripe-1)) + 1;
7450                 mddev->queue->limits.discard_alignment = stripe;
7451                 mddev->queue->limits.discard_granularity = stripe;
7452
7453                 blk_queue_max_write_same_sectors(mddev->queue, 0);
7454                 blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
7455
7456                 rdev_for_each(rdev, mddev) {
7457                         disk_stack_limits(mddev->gendisk, rdev->bdev,
7458                                           rdev->data_offset << 9);
7459                         disk_stack_limits(mddev->gendisk, rdev->bdev,
7460                                           rdev->new_data_offset << 9);
7461                 }
7462
7463                 /*
7464                  * zeroing is required, otherwise data
7465                  * could be lost. Consider a scenario: discard a stripe
7466                  * (the stripe could be inconsistent if
7467                  * discard_zeroes_data is 0); write one disk of the
7468                  * stripe (the stripe could be inconsistent again
7469                  * depending on which disks are used to calculate
7470                  * parity); the disk is broken; The stripe data of this
7471                  * disk is lost.
7472                  *
7473                  * We only allow DISCARD if the sysadmin has confirmed that
7474                  * only safe devices are in use by setting a module parameter.
7475                  * A better idea might be to turn DISCARD into WRITE_ZEROES
7476                  * requests, as that is required to be safe.
7477                  */
7478                 if (devices_handle_discard_safely &&
7479                     mddev->queue->limits.max_discard_sectors >= (stripe >> 9) &&
7480                     mddev->queue->limits.discard_granularity >= stripe)
7481                         blk_queue_flag_set(QUEUE_FLAG_DISCARD,
7482                                                 mddev->queue);
7483                 else
7484                         blk_queue_flag_clear(QUEUE_FLAG_DISCARD,
7485                                                 mddev->queue);
7486
7487                 blk_queue_max_hw_sectors(mddev->queue, UINT_MAX);
7488         }
7489
7490         if (log_init(conf, journal_dev, raid5_has_ppl(conf)))
7491                 goto abort;
7492
7493         return 0;
7494 abort:
7495         md_unregister_thread(&mddev->thread);
7496         print_raid5_conf(conf);
7497         free_conf(conf);
7498         mddev->private = NULL;
7499         pr_warn("md/raid:%s: failed to run raid set.\n", mdname(mddev));
7500         return -EIO;
7501 }
7502
7503 static void raid5_free(struct mddev *mddev, void *priv)
7504 {
7505         struct r5conf *conf = priv;
7506
7507         free_conf(conf);
7508         mddev->to_remove = &raid5_attrs_group;
7509 }
7510
7511 static void raid5_status(struct seq_file *seq, struct mddev *mddev)
7512 {
7513         struct r5conf *conf = mddev->private;
7514         int i;
7515
7516         seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
7517                 conf->chunk_sectors / 2, mddev->layout);
7518         seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
7519         rcu_read_lock();
7520         for (i = 0; i < conf->raid_disks; i++) {
7521                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
7522                 seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
7523         }
7524         rcu_read_unlock();
7525         seq_printf (seq, "]");
7526 }
7527
7528 static void print_raid5_conf (struct r5conf *conf)
7529 {
7530         int i;
7531         struct disk_info *tmp;
7532
7533         pr_debug("RAID conf printout:\n");
7534         if (!conf) {
7535                 pr_debug("(conf==NULL)\n");
7536                 return;
7537         }
7538         pr_debug(" --- level:%d rd:%d wd:%d\n", conf->level,
7539                conf->raid_disks,
7540                conf->raid_disks - conf->mddev->degraded);
7541
7542         for (i = 0; i < conf->raid_disks; i++) {
7543                 char b[BDEVNAME_SIZE];
7544                 tmp = conf->disks + i;
7545                 if (tmp->rdev)
7546                         pr_debug(" disk %d, o:%d, dev:%s\n",
7547                                i, !test_bit(Faulty, &tmp->rdev->flags),
7548                                bdevname(tmp->rdev->bdev, b));
7549         }
7550 }
7551
7552 static int raid5_spare_active(struct mddev *mddev)
7553 {
7554         int i;
7555         struct r5conf *conf = mddev->private;
7556         struct disk_info *tmp;
7557         int count = 0;
7558         unsigned long flags;
7559
7560         for (i = 0; i < conf->raid_disks; i++) {
7561                 tmp = conf->disks + i;
7562                 if (tmp->replacement
7563                     && tmp->replacement->recovery_offset == MaxSector
7564                     && !test_bit(Faulty, &tmp->replacement->flags)
7565                     && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
7566                         /* Replacement has just become active. */
7567                         if (!tmp->rdev
7568                             || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
7569                                 count++;
7570                         if (tmp->rdev) {
7571                                 /* Replaced device not technically faulty,
7572                                  * but we need to be sure it gets removed
7573                                  * and never re-added.
7574                                  */
7575                                 set_bit(Faulty, &tmp->rdev->flags);
7576                                 sysfs_notify_dirent_safe(
7577                                         tmp->rdev->sysfs_state);
7578                         }
7579                         sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
7580                 } else if (tmp->rdev
7581                     && tmp->rdev->recovery_offset == MaxSector
7582                     && !test_bit(Faulty, &tmp->rdev->flags)
7583                     && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
7584                         count++;
7585                         sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
7586                 }
7587         }
7588         spin_lock_irqsave(&conf->device_lock, flags);
7589         mddev->degraded = raid5_calc_degraded(conf);
7590         spin_unlock_irqrestore(&conf->device_lock, flags);
7591         print_raid5_conf(conf);
7592         return count;
7593 }
7594
7595 static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
7596 {
7597         struct r5conf *conf = mddev->private;
7598         int err = 0;
7599         int number = rdev->raid_disk;
7600         struct md_rdev **rdevp;
7601         struct disk_info *p = conf->disks + number;
7602
7603         print_raid5_conf(conf);
7604         if (test_bit(Journal, &rdev->flags) && conf->log) {
7605                 /*
7606                  * we can't wait pending write here, as this is called in
7607                  * raid5d, wait will deadlock.
7608                  * neilb: there is no locking about new writes here,
7609                  * so this cannot be safe.
7610                  */
7611                 if (atomic_read(&conf->active_stripes) ||
7612                     atomic_read(&conf->r5c_cached_full_stripes) ||
7613                     atomic_read(&conf->r5c_cached_partial_stripes)) {
7614                         return -EBUSY;
7615                 }
7616                 log_exit(conf);
7617                 return 0;
7618         }
7619         if (rdev == p->rdev)
7620                 rdevp = &p->rdev;
7621         else if (rdev == p->replacement)
7622                 rdevp = &p->replacement;
7623         else
7624                 return 0;
7625
7626         if (number >= conf->raid_disks &&
7627             conf->reshape_progress == MaxSector)
7628                 clear_bit(In_sync, &rdev->flags);
7629
7630         if (test_bit(In_sync, &rdev->flags) ||
7631             atomic_read(&rdev->nr_pending)) {
7632                 err = -EBUSY;
7633                 goto abort;
7634         }
7635         /* Only remove non-faulty devices if recovery
7636          * isn't possible.
7637          */
7638         if (!test_bit(Faulty, &rdev->flags) &&
7639             mddev->recovery_disabled != conf->recovery_disabled &&
7640             !has_failed(conf) &&
7641             (!p->replacement || p->replacement == rdev) &&
7642             number < conf->raid_disks) {
7643                 err = -EBUSY;
7644                 goto abort;
7645         }
7646         *rdevp = NULL;
7647         if (!test_bit(RemoveSynchronized, &rdev->flags)) {
7648                 synchronize_rcu();
7649                 if (atomic_read(&rdev->nr_pending)) {
7650                         /* lost the race, try later */
7651                         err = -EBUSY;
7652                         *rdevp = rdev;
7653                 }
7654         }
7655         if (!err) {
7656                 err = log_modify(conf, rdev, false);
7657                 if (err)
7658                         goto abort;
7659         }
7660         if (p->replacement) {
7661                 /* We must have just cleared 'rdev' */
7662                 p->rdev = p->replacement;
7663                 clear_bit(Replacement, &p->replacement->flags);
7664                 smp_mb(); /* Make sure other CPUs may see both as identical
7665                            * but will never see neither - if they are careful
7666                            */
7667                 p->replacement = NULL;
7668
7669                 if (!err)
7670                         err = log_modify(conf, p->rdev, true);
7671         }
7672
7673         clear_bit(WantReplacement, &rdev->flags);
7674 abort:
7675
7676         print_raid5_conf(conf);
7677         return err;
7678 }
7679
7680 static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
7681 {
7682         struct r5conf *conf = mddev->private;
7683         int err = -EEXIST;
7684         int disk;
7685         struct disk_info *p;
7686         int first = 0;
7687         int last = conf->raid_disks - 1;
7688
7689         if (test_bit(Journal, &rdev->flags)) {
7690                 if (conf->log)
7691                         return -EBUSY;
7692
7693                 rdev->raid_disk = 0;
7694                 /*
7695                  * The array is in readonly mode if journal is missing, so no
7696                  * write requests running. We should be safe
7697                  */
7698                 log_init(conf, rdev, false);
7699                 return 0;
7700         }
7701         if (mddev->recovery_disabled == conf->recovery_disabled)
7702                 return -EBUSY;
7703
7704         if (rdev->saved_raid_disk < 0 && has_failed(conf))
7705                 /* no point adding a device */
7706                 return -EINVAL;
7707
7708         if (rdev->raid_disk >= 0)
7709                 first = last = rdev->raid_disk;
7710
7711         /*
7712          * find the disk ... but prefer rdev->saved_raid_disk
7713          * if possible.
7714          */
7715         if (rdev->saved_raid_disk >= 0 &&
7716             rdev->saved_raid_disk >= first &&
7717             conf->disks[rdev->saved_raid_disk].rdev == NULL)
7718                 first = rdev->saved_raid_disk;
7719
7720         for (disk = first; disk <= last; disk++) {
7721                 p = conf->disks + disk;
7722                 if (p->rdev == NULL) {
7723                         clear_bit(In_sync, &rdev->flags);
7724                         rdev->raid_disk = disk;
7725                         if (rdev->saved_raid_disk != disk)
7726                                 conf->fullsync = 1;
7727                         rcu_assign_pointer(p->rdev, rdev);
7728
7729                         err = log_modify(conf, rdev, true);
7730
7731                         goto out;
7732                 }
7733         }
7734         for (disk = first; disk <= last; disk++) {
7735                 p = conf->disks + disk;
7736                 if (test_bit(WantReplacement, &p->rdev->flags) &&
7737                     p->replacement == NULL) {
7738                         clear_bit(In_sync, &rdev->flags);
7739                         set_bit(Replacement, &rdev->flags);
7740                         rdev->raid_disk = disk;
7741                         err = 0;
7742                         conf->fullsync = 1;
7743                         rcu_assign_pointer(p->replacement, rdev);
7744                         break;
7745                 }
7746         }
7747 out:
7748         print_raid5_conf(conf);
7749         return err;
7750 }
7751
7752 static int raid5_resize(struct mddev *mddev, sector_t sectors)
7753 {
7754         /* no resync is happening, and there is enough space
7755          * on all devices, so we can resize.
7756          * We need to make sure resync covers any new space.
7757          * If the array is shrinking we should possibly wait until
7758          * any io in the removed space completes, but it hardly seems
7759          * worth it.
7760          */
7761         sector_t newsize;
7762         struct r5conf *conf = mddev->private;
7763
7764         if (raid5_has_log(conf) || raid5_has_ppl(conf))
7765                 return -EINVAL;
7766         sectors &= ~((sector_t)conf->chunk_sectors - 1);
7767         newsize = raid5_size(mddev, sectors, mddev->raid_disks);
7768         if (mddev->external_size &&
7769             mddev->array_sectors > newsize)
7770                 return -EINVAL;
7771         if (mddev->bitmap) {
7772                 int ret = md_bitmap_resize(mddev->bitmap, sectors, 0, 0);
7773                 if (ret)
7774                         return ret;
7775         }
7776         md_set_array_sectors(mddev, newsize);
7777         if (sectors > mddev->dev_sectors &&
7778             mddev->recovery_cp > mddev->dev_sectors) {
7779                 mddev->recovery_cp = mddev->dev_sectors;
7780                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7781         }
7782         mddev->dev_sectors = sectors;
7783         mddev->resync_max_sectors = sectors;
7784         return 0;
7785 }
7786
7787 static int check_stripe_cache(struct mddev *mddev)
7788 {
7789         /* Can only proceed if there are plenty of stripe_heads.
7790          * We need a minimum of one full stripe,, and for sensible progress
7791          * it is best to have about 4 times that.
7792          * If we require 4 times, then the default 256 4K stripe_heads will
7793          * allow for chunk sizes up to 256K, which is probably OK.
7794          * If the chunk size is greater, user-space should request more
7795          * stripe_heads first.
7796          */
7797         struct r5conf *conf = mddev->private;
7798         if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4
7799             > conf->min_nr_stripes ||
7800             ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4
7801             > conf->min_nr_stripes) {
7802                 pr_warn("md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
7803                         mdname(mddev),
7804                         ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
7805                          / STRIPE_SIZE)*4);
7806                 return 0;
7807         }
7808         return 1;
7809 }
7810
7811 static int check_reshape(struct mddev *mddev)
7812 {
7813         struct r5conf *conf = mddev->private;
7814
7815         if (raid5_has_log(conf) || raid5_has_ppl(conf))
7816                 return -EINVAL;
7817         if (mddev->delta_disks == 0 &&
7818             mddev->new_layout == mddev->layout &&
7819             mddev->new_chunk_sectors == mddev->chunk_sectors)
7820                 return 0; /* nothing to do */
7821         if (has_failed(conf))
7822                 return -EINVAL;
7823         if (mddev->delta_disks < 0 && mddev->reshape_position == MaxSector) {
7824                 /* We might be able to shrink, but the devices must
7825                  * be made bigger first.
7826                  * For raid6, 4 is the minimum size.
7827                  * Otherwise 2 is the minimum
7828                  */
7829                 int min = 2;
7830                 if (mddev->level == 6)
7831                         min = 4;
7832                 if (mddev->raid_disks + mddev->delta_disks < min)
7833                         return -EINVAL;
7834         }
7835
7836         if (!check_stripe_cache(mddev))
7837                 return -ENOSPC;
7838
7839         if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
7840             mddev->delta_disks > 0)
7841                 if (resize_chunks(conf,
7842                                   conf->previous_raid_disks
7843                                   + max(0, mddev->delta_disks),
7844                                   max(mddev->new_chunk_sectors,
7845                                       mddev->chunk_sectors)
7846                             ) < 0)
7847                         return -ENOMEM;
7848
7849         if (conf->previous_raid_disks + mddev->delta_disks <= conf->pool_size)
7850                 return 0; /* never bother to shrink */
7851         return resize_stripes(conf, (conf->previous_raid_disks
7852                                      + mddev->delta_disks));
7853 }
7854
7855 static int raid5_start_reshape(struct mddev *mddev)
7856 {
7857         struct r5conf *conf = mddev->private;
7858         struct md_rdev *rdev;
7859         int spares = 0;
7860         unsigned long flags;
7861
7862         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
7863                 return -EBUSY;
7864
7865         if (!check_stripe_cache(mddev))
7866                 return -ENOSPC;
7867
7868         if (has_failed(conf))
7869                 return -EINVAL;
7870
7871         rdev_for_each(rdev, mddev) {
7872                 if (!test_bit(In_sync, &rdev->flags)
7873                     && !test_bit(Faulty, &rdev->flags))
7874                         spares++;
7875         }
7876
7877         if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
7878                 /* Not enough devices even to make a degraded array
7879                  * of that size
7880                  */
7881                 return -EINVAL;
7882
7883         /* Refuse to reduce size of the array.  Any reductions in
7884          * array size must be through explicit setting of array_size
7885          * attribute.
7886          */
7887         if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
7888             < mddev->array_sectors) {
7889                 pr_warn("md/raid:%s: array size must be reduced before number of disks\n",
7890                         mdname(mddev));
7891                 return -EINVAL;
7892         }
7893
7894         atomic_set(&conf->reshape_stripes, 0);
7895         spin_lock_irq(&conf->device_lock);
7896         write_seqcount_begin(&conf->gen_lock);
7897         conf->previous_raid_disks = conf->raid_disks;
7898         conf->raid_disks += mddev->delta_disks;
7899         conf->prev_chunk_sectors = conf->chunk_sectors;
7900         conf->chunk_sectors = mddev->new_chunk_sectors;
7901         conf->prev_algo = conf->algorithm;
7902         conf->algorithm = mddev->new_layout;
7903         conf->generation++;
7904         /* Code that selects data_offset needs to see the generation update
7905          * if reshape_progress has been set - so a memory barrier needed.
7906          */
7907         smp_mb();
7908         if (mddev->reshape_backwards)
7909                 conf->reshape_progress = raid5_size(mddev, 0, 0);
7910         else
7911                 conf->reshape_progress = 0;
7912         conf->reshape_safe = conf->reshape_progress;
7913         write_seqcount_end(&conf->gen_lock);
7914         spin_unlock_irq(&conf->device_lock);
7915
7916         /* Now make sure any requests that proceeded on the assumption
7917          * the reshape wasn't running - like Discard or Read - have
7918          * completed.
7919          */
7920         mddev_suspend(mddev);
7921         mddev_resume(mddev);
7922
7923         /* Add some new drives, as many as will fit.
7924          * We know there are enough to make the newly sized array work.
7925          * Don't add devices if we are reducing the number of
7926          * devices in the array.  This is because it is not possible
7927          * to correctly record the "partially reconstructed" state of
7928          * such devices during the reshape and confusion could result.
7929          */
7930         if (mddev->delta_disks >= 0) {
7931                 rdev_for_each(rdev, mddev)
7932                         if (rdev->raid_disk < 0 &&
7933                             !test_bit(Faulty, &rdev->flags)) {
7934                                 if (raid5_add_disk(mddev, rdev) == 0) {
7935                                         if (rdev->raid_disk
7936                                             >= conf->previous_raid_disks)
7937                                                 set_bit(In_sync, &rdev->flags);
7938                                         else
7939                                                 rdev->recovery_offset = 0;
7940
7941                                         if (sysfs_link_rdev(mddev, rdev))
7942                                                 /* Failure here is OK */;
7943                                 }
7944                         } else if (rdev->raid_disk >= conf->previous_raid_disks
7945                                    && !test_bit(Faulty, &rdev->flags)) {
7946                                 /* This is a spare that was manually added */
7947                                 set_bit(In_sync, &rdev->flags);
7948                         }
7949
7950                 /* When a reshape changes the number of devices,
7951                  * ->degraded is measured against the larger of the
7952                  * pre and post number of devices.
7953                  */
7954                 spin_lock_irqsave(&conf->device_lock, flags);
7955                 mddev->degraded = raid5_calc_degraded(conf);
7956                 spin_unlock_irqrestore(&conf->device_lock, flags);
7957         }
7958         mddev->raid_disks = conf->raid_disks;
7959         mddev->reshape_position = conf->reshape_progress;
7960         set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
7961
7962         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7963         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7964         clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
7965         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7966         set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7967         mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7968                                                 "reshape");
7969         if (!mddev->sync_thread) {
7970                 mddev->recovery = 0;
7971                 spin_lock_irq(&conf->device_lock);
7972                 write_seqcount_begin(&conf->gen_lock);
7973                 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
7974                 mddev->new_chunk_sectors =
7975                         conf->chunk_sectors = conf->prev_chunk_sectors;
7976                 mddev->new_layout = conf->algorithm = conf->prev_algo;
7977                 rdev_for_each(rdev, mddev)
7978                         rdev->new_data_offset = rdev->data_offset;
7979                 smp_wmb();
7980                 conf->generation --;
7981                 conf->reshape_progress = MaxSector;
7982                 mddev->reshape_position = MaxSector;
7983                 write_seqcount_end(&conf->gen_lock);
7984                 spin_unlock_irq(&conf->device_lock);
7985                 return -EAGAIN;
7986         }
7987         conf->reshape_checkpoint = jiffies;
7988         md_wakeup_thread(mddev->sync_thread);
7989         md_new_event(mddev);
7990         return 0;
7991 }
7992
7993 /* This is called from the reshape thread and should make any
7994  * changes needed in 'conf'
7995  */
7996 static void end_reshape(struct r5conf *conf)
7997 {
7998
7999         if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
8000                 struct md_rdev *rdev;
8001
8002                 spin_lock_irq(&conf->device_lock);
8003                 conf->previous_raid_disks = conf->raid_disks;
8004                 md_finish_reshape(conf->mddev);
8005                 smp_wmb();
8006                 conf->reshape_progress = MaxSector;
8007                 conf->mddev->reshape_position = MaxSector;
8008                 rdev_for_each(rdev, conf->mddev)
8009                         if (rdev->raid_disk >= 0 &&
8010                             !test_bit(Journal, &rdev->flags) &&
8011                             !test_bit(In_sync, &rdev->flags))
8012                                 rdev->recovery_offset = MaxSector;
8013                 spin_unlock_irq(&conf->device_lock);
8014                 wake_up(&conf->wait_for_overlap);
8015
8016                 /* read-ahead size must cover two whole stripes, which is
8017                  * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
8018                  */
8019                 if (conf->mddev->queue) {
8020                         int data_disks = conf->raid_disks - conf->max_degraded;
8021                         int stripe = data_disks * ((conf->chunk_sectors << 9)
8022                                                    / PAGE_SIZE);
8023                         if (conf->mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
8024                                 conf->mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
8025                 }
8026         }
8027 }
8028
8029 /* This is called from the raid5d thread with mddev_lock held.
8030  * It makes config changes to the device.
8031  */
8032 static void raid5_finish_reshape(struct mddev *mddev)
8033 {
8034         struct r5conf *conf = mddev->private;
8035
8036         if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
8037
8038                 if (mddev->delta_disks <= 0) {
8039                         int d;
8040                         spin_lock_irq(&conf->device_lock);
8041                         mddev->degraded = raid5_calc_degraded(conf);
8042                         spin_unlock_irq(&conf->device_lock);
8043                         for (d = conf->raid_disks ;
8044                              d < conf->raid_disks - mddev->delta_disks;
8045                              d++) {
8046                                 struct md_rdev *rdev = conf->disks[d].rdev;
8047                                 if (rdev)
8048                                         clear_bit(In_sync, &rdev->flags);
8049                                 rdev = conf->disks[d].replacement;
8050                                 if (rdev)
8051                                         clear_bit(In_sync, &rdev->flags);
8052                         }
8053                 }
8054                 mddev->layout = conf->algorithm;
8055                 mddev->chunk_sectors = conf->chunk_sectors;
8056                 mddev->reshape_position = MaxSector;
8057                 mddev->delta_disks = 0;
8058                 mddev->reshape_backwards = 0;
8059         }
8060 }
8061
8062 static void raid5_quiesce(struct mddev *mddev, int quiesce)
8063 {
8064         struct r5conf *conf = mddev->private;
8065
8066         if (quiesce) {
8067                 /* stop all writes */
8068                 lock_all_device_hash_locks_irq(conf);
8069                 /* '2' tells resync/reshape to pause so that all
8070                  * active stripes can drain
8071                  */
8072                 r5c_flush_cache(conf, INT_MAX);
8073                 conf->quiesce = 2;
8074                 wait_event_cmd(conf->wait_for_quiescent,
8075                                     atomic_read(&conf->active_stripes) == 0 &&
8076                                     atomic_read(&conf->active_aligned_reads) == 0,
8077                                     unlock_all_device_hash_locks_irq(conf),
8078                                     lock_all_device_hash_locks_irq(conf));
8079                 conf->quiesce = 1;
8080                 unlock_all_device_hash_locks_irq(conf);
8081                 /* allow reshape to continue */
8082                 wake_up(&conf->wait_for_overlap);
8083         } else {
8084                 /* re-enable writes */
8085                 lock_all_device_hash_locks_irq(conf);
8086                 conf->quiesce = 0;
8087                 wake_up(&conf->wait_for_quiescent);
8088                 wake_up(&conf->wait_for_overlap);
8089                 unlock_all_device_hash_locks_irq(conf);
8090         }
8091         log_quiesce(conf, quiesce);
8092 }
8093
8094 static void *raid45_takeover_raid0(struct mddev *mddev, int level)
8095 {
8096         struct r0conf *raid0_conf = mddev->private;
8097         sector_t sectors;
8098
8099         /* for raid0 takeover only one zone is supported */
8100         if (raid0_conf->nr_strip_zones > 1) {
8101                 pr_warn("md/raid:%s: cannot takeover raid0 with more than one zone.\n",
8102                         mdname(mddev));
8103                 return ERR_PTR(-EINVAL);
8104         }
8105
8106         sectors = raid0_conf->strip_zone[0].zone_end;
8107         sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
8108         mddev->dev_sectors = sectors;
8109         mddev->new_level = level;
8110         mddev->new_layout = ALGORITHM_PARITY_N;
8111         mddev->new_chunk_sectors = mddev->chunk_sectors;
8112         mddev->raid_disks += 1;
8113         mddev->delta_disks = 1;
8114         /* make sure it will be not marked as dirty */
8115         mddev->recovery_cp = MaxSector;
8116
8117         return setup_conf(mddev);
8118 }
8119
8120 static void *raid5_takeover_raid1(struct mddev *mddev)
8121 {
8122         int chunksect;
8123         void *ret;
8124
8125         if (mddev->raid_disks != 2 ||
8126             mddev->degraded > 1)
8127                 return ERR_PTR(-EINVAL);
8128
8129         /* Should check if there are write-behind devices? */
8130
8131         chunksect = 64*2; /* 64K by default */
8132
8133         /* The array must be an exact multiple of chunksize */
8134         while (chunksect && (mddev->array_sectors & (chunksect-1)))
8135                 chunksect >>= 1;
8136
8137         if ((chunksect<<9) < STRIPE_SIZE)
8138                 /* array size does not allow a suitable chunk size */
8139                 return ERR_PTR(-EINVAL);
8140
8141         mddev->new_level = 5;
8142         mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
8143         mddev->new_chunk_sectors = chunksect;
8144
8145         ret = setup_conf(mddev);
8146         if (!IS_ERR(ret))
8147                 mddev_clear_unsupported_flags(mddev,
8148                         UNSUPPORTED_MDDEV_FLAGS);
8149         return ret;
8150 }
8151
8152 static void *raid5_takeover_raid6(struct mddev *mddev)
8153 {
8154         int new_layout;
8155
8156         switch (mddev->layout) {
8157         case ALGORITHM_LEFT_ASYMMETRIC_6:
8158                 new_layout = ALGORITHM_LEFT_ASYMMETRIC;
8159                 break;
8160         case ALGORITHM_RIGHT_ASYMMETRIC_6:
8161                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
8162                 break;
8163         case ALGORITHM_LEFT_SYMMETRIC_6:
8164                 new_layout = ALGORITHM_LEFT_SYMMETRIC;
8165                 break;
8166         case ALGORITHM_RIGHT_SYMMETRIC_6:
8167                 new_layout = ALGORITHM_RIGHT_SYMMETRIC;
8168                 break;
8169         case ALGORITHM_PARITY_0_6:
8170                 new_layout = ALGORITHM_PARITY_0;
8171                 break;
8172         case ALGORITHM_PARITY_N:
8173                 new_layout = ALGORITHM_PARITY_N;
8174                 break;
8175         default:
8176                 return ERR_PTR(-EINVAL);
8177         }
8178         mddev->new_level = 5;
8179         mddev->new_layout = new_layout;
8180         mddev->delta_disks = -1;
8181         mddev->raid_disks -= 1;
8182         return setup_conf(mddev);
8183 }
8184
8185 static int raid5_check_reshape(struct mddev *mddev)
8186 {
8187         /* For a 2-drive array, the layout and chunk size can be changed
8188          * immediately as not restriping is needed.
8189          * For larger arrays we record the new value - after validation
8190          * to be used by a reshape pass.
8191          */
8192         struct r5conf *conf = mddev->private;
8193         int new_chunk = mddev->new_chunk_sectors;
8194
8195         if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
8196                 return -EINVAL;
8197         if (new_chunk > 0) {
8198                 if (!is_power_of_2(new_chunk))
8199                         return -EINVAL;
8200                 if (new_chunk < (PAGE_SIZE>>9))
8201                         return -EINVAL;
8202                 if (mddev->array_sectors & (new_chunk-1))
8203                         /* not factor of array size */
8204                         return -EINVAL;
8205         }
8206
8207         /* They look valid */
8208
8209         if (mddev->raid_disks == 2) {
8210                 /* can make the change immediately */
8211                 if (mddev->new_layout >= 0) {
8212                         conf->algorithm = mddev->new_layout;
8213                         mddev->layout = mddev->new_layout;
8214                 }
8215                 if (new_chunk > 0) {
8216                         conf->chunk_sectors = new_chunk ;
8217                         mddev->chunk_sectors = new_chunk;
8218                 }
8219                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8220                 md_wakeup_thread(mddev->thread);
8221         }
8222         return check_reshape(mddev);
8223 }
8224
8225 static int raid6_check_reshape(struct mddev *mddev)
8226 {
8227         int new_chunk = mddev->new_chunk_sectors;
8228
8229         if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
8230                 return -EINVAL;
8231         if (new_chunk > 0) {
8232                 if (!is_power_of_2(new_chunk))
8233                         return -EINVAL;
8234                 if (new_chunk < (PAGE_SIZE >> 9))
8235                         return -EINVAL;
8236                 if (mddev->array_sectors & (new_chunk-1))
8237                         /* not factor of array size */
8238                         return -EINVAL;
8239         }
8240
8241         /* They look valid */
8242         return check_reshape(mddev);
8243 }
8244
8245 static void *raid5_takeover(struct mddev *mddev)
8246 {
8247         /* raid5 can take over:
8248          *  raid0 - if there is only one strip zone - make it a raid4 layout
8249          *  raid1 - if there are two drives.  We need to know the chunk size
8250          *  raid4 - trivial - just use a raid4 layout.
8251          *  raid6 - Providing it is a *_6 layout
8252          */
8253         if (mddev->level == 0)
8254                 return raid45_takeover_raid0(mddev, 5);
8255         if (mddev->level == 1)
8256                 return raid5_takeover_raid1(mddev);
8257         if (mddev->level == 4) {
8258                 mddev->new_layout = ALGORITHM_PARITY_N;
8259                 mddev->new_level = 5;
8260                 return setup_conf(mddev);
8261         }
8262         if (mddev->level == 6)
8263                 return raid5_takeover_raid6(mddev);
8264
8265         return ERR_PTR(-EINVAL);
8266 }
8267
8268 static void *raid4_takeover(struct mddev *mddev)
8269 {
8270         /* raid4 can take over:
8271          *  raid0 - if there is only one strip zone
8272          *  raid5 - if layout is right
8273          */
8274         if (mddev->level == 0)
8275                 return raid45_takeover_raid0(mddev, 4);
8276         if (mddev->level == 5 &&
8277             mddev->layout == ALGORITHM_PARITY_N) {
8278                 mddev->new_layout = 0;
8279                 mddev->new_level = 4;
8280                 return setup_conf(mddev);
8281         }
8282         return ERR_PTR(-EINVAL);
8283 }
8284
8285 static struct md_personality raid5_personality;
8286
8287 static void *raid6_takeover(struct mddev *mddev)
8288 {
8289         /* Currently can only take over a raid5.  We map the
8290          * personality to an equivalent raid6 personality
8291          * with the Q block at the end.
8292          */
8293         int new_layout;
8294
8295         if (mddev->pers != &raid5_personality)
8296                 return ERR_PTR(-EINVAL);
8297         if (mddev->degraded > 1)
8298                 return ERR_PTR(-EINVAL);
8299         if (mddev->raid_disks > 253)
8300                 return ERR_PTR(-EINVAL);
8301         if (mddev->raid_disks < 3)
8302                 return ERR_PTR(-EINVAL);
8303
8304         switch (mddev->layout) {
8305         case ALGORITHM_LEFT_ASYMMETRIC:
8306                 new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
8307                 break;
8308         case ALGORITHM_RIGHT_ASYMMETRIC:
8309                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
8310                 break;
8311         case ALGORITHM_LEFT_SYMMETRIC:
8312                 new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
8313                 break;
8314         case ALGORITHM_RIGHT_SYMMETRIC:
8315                 new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
8316                 break;
8317         case ALGORITHM_PARITY_0:
8318                 new_layout = ALGORITHM_PARITY_0_6;
8319                 break;
8320         case ALGORITHM_PARITY_N:
8321                 new_layout = ALGORITHM_PARITY_N;
8322                 break;
8323         default:
8324                 return ERR_PTR(-EINVAL);
8325         }
8326         mddev->new_level = 6;
8327         mddev->new_layout = new_layout;
8328         mddev->delta_disks = 1;
8329         mddev->raid_disks += 1;
8330         return setup_conf(mddev);
8331 }
8332
8333 static int raid5_change_consistency_policy(struct mddev *mddev, const char *buf)
8334 {
8335         struct r5conf *conf;
8336         int err;
8337
8338         err = mddev_lock(mddev);
8339         if (err)
8340                 return err;
8341         conf = mddev->private;
8342         if (!conf) {
8343                 mddev_unlock(mddev);
8344                 return -ENODEV;
8345         }
8346
8347         if (strncmp(buf, "ppl", 3) == 0) {
8348                 /* ppl only works with RAID 5 */
8349                 if (!raid5_has_ppl(conf) && conf->level == 5) {
8350                         err = log_init(conf, NULL, true);
8351                         if (!err) {
8352                                 err = resize_stripes(conf, conf->pool_size);
8353                                 if (err)
8354                                         log_exit(conf);
8355                         }
8356                 } else
8357                         err = -EINVAL;
8358         } else if (strncmp(buf, "resync", 6) == 0) {
8359                 if (raid5_has_ppl(conf)) {
8360                         mddev_suspend(mddev);
8361                         log_exit(conf);
8362                         mddev_resume(mddev);
8363                         err = resize_stripes(conf, conf->pool_size);
8364                 } else if (test_bit(MD_HAS_JOURNAL, &conf->mddev->flags) &&
8365                            r5l_log_disk_error(conf)) {
8366                         bool journal_dev_exists = false;
8367                         struct md_rdev *rdev;
8368
8369                         rdev_for_each(rdev, mddev)
8370                                 if (test_bit(Journal, &rdev->flags)) {
8371                                         journal_dev_exists = true;
8372                                         break;
8373                                 }
8374
8375                         if (!journal_dev_exists) {
8376                                 mddev_suspend(mddev);
8377                                 clear_bit(MD_HAS_JOURNAL, &mddev->flags);
8378                                 mddev_resume(mddev);
8379                         } else  /* need remove journal device first */
8380                                 err = -EBUSY;
8381                 } else
8382                         err = -EINVAL;
8383         } else {
8384                 err = -EINVAL;
8385         }
8386
8387         if (!err)
8388                 md_update_sb(mddev, 1);
8389
8390         mddev_unlock(mddev);
8391
8392         return err;
8393 }
8394
8395 static int raid5_start(struct mddev *mddev)
8396 {
8397         struct r5conf *conf = mddev->private;
8398
8399         return r5l_start(conf->log);
8400 }
8401
8402 static struct md_personality raid6_personality =
8403 {
8404         .name           = "raid6",
8405         .level          = 6,
8406         .owner          = THIS_MODULE,
8407         .make_request   = raid5_make_request,
8408         .run            = raid5_run,
8409         .start          = raid5_start,
8410         .free           = raid5_free,
8411         .status         = raid5_status,
8412         .error_handler  = raid5_error,
8413         .hot_add_disk   = raid5_add_disk,
8414         .hot_remove_disk= raid5_remove_disk,
8415         .spare_active   = raid5_spare_active,
8416         .sync_request   = raid5_sync_request,
8417         .resize         = raid5_resize,
8418         .size           = raid5_size,
8419         .check_reshape  = raid6_check_reshape,
8420         .start_reshape  = raid5_start_reshape,
8421         .finish_reshape = raid5_finish_reshape,
8422         .quiesce        = raid5_quiesce,
8423         .takeover       = raid6_takeover,
8424         .congested      = raid5_congested,
8425         .change_consistency_policy = raid5_change_consistency_policy,
8426 };
8427 static struct md_personality raid5_personality =
8428 {
8429         .name           = "raid5",
8430         .level          = 5,
8431         .owner          = THIS_MODULE,
8432         .make_request   = raid5_make_request,
8433         .run            = raid5_run,
8434         .start          = raid5_start,
8435         .free           = raid5_free,
8436         .status         = raid5_status,
8437         .error_handler  = raid5_error,
8438         .hot_add_disk   = raid5_add_disk,
8439         .hot_remove_disk= raid5_remove_disk,
8440         .spare_active   = raid5_spare_active,
8441         .sync_request   = raid5_sync_request,
8442         .resize         = raid5_resize,
8443         .size           = raid5_size,
8444         .check_reshape  = raid5_check_reshape,
8445         .start_reshape  = raid5_start_reshape,
8446         .finish_reshape = raid5_finish_reshape,
8447         .quiesce        = raid5_quiesce,
8448         .takeover       = raid5_takeover,
8449         .congested      = raid5_congested,
8450         .change_consistency_policy = raid5_change_consistency_policy,
8451 };
8452
8453 static struct md_personality raid4_personality =
8454 {
8455         .name           = "raid4",
8456         .level          = 4,
8457         .owner          = THIS_MODULE,
8458         .make_request   = raid5_make_request,
8459         .run            = raid5_run,
8460         .start          = raid5_start,
8461         .free           = raid5_free,
8462         .status         = raid5_status,
8463         .error_handler  = raid5_error,
8464         .hot_add_disk   = raid5_add_disk,
8465         .hot_remove_disk= raid5_remove_disk,
8466         .spare_active   = raid5_spare_active,
8467         .sync_request   = raid5_sync_request,
8468         .resize         = raid5_resize,
8469         .size           = raid5_size,
8470         .check_reshape  = raid5_check_reshape,
8471         .start_reshape  = raid5_start_reshape,
8472         .finish_reshape = raid5_finish_reshape,
8473         .quiesce        = raid5_quiesce,
8474         .takeover       = raid4_takeover,
8475         .congested      = raid5_congested,
8476         .change_consistency_policy = raid5_change_consistency_policy,
8477 };
8478
8479 static int __init raid5_init(void)
8480 {
8481         int ret;
8482
8483         raid5_wq = alloc_workqueue("raid5wq",
8484                 WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE|WQ_SYSFS, 0);
8485         if (!raid5_wq)
8486                 return -ENOMEM;
8487
8488         ret = cpuhp_setup_state_multi(CPUHP_MD_RAID5_PREPARE,
8489                                       "md/raid5:prepare",
8490                                       raid456_cpu_up_prepare,
8491                                       raid456_cpu_dead);
8492         if (ret) {
8493                 destroy_workqueue(raid5_wq);
8494                 return ret;
8495         }
8496         register_md_personality(&raid6_personality);
8497         register_md_personality(&raid5_personality);
8498         register_md_personality(&raid4_personality);
8499         return 0;
8500 }
8501
8502 static void raid5_exit(void)
8503 {
8504         unregister_md_personality(&raid6_personality);
8505         unregister_md_personality(&raid5_personality);
8506         unregister_md_personality(&raid4_personality);
8507         cpuhp_remove_multi_state(CPUHP_MD_RAID5_PREPARE);
8508         destroy_workqueue(raid5_wq);
8509 }
8510
8511 module_init(raid5_init);
8512 module_exit(raid5_exit);
8513 MODULE_LICENSE("GPL");
8514 MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
8515 MODULE_ALIAS("md-personality-4"); /* RAID5 */
8516 MODULE_ALIAS("md-raid5");
8517 MODULE_ALIAS("md-raid4");
8518 MODULE_ALIAS("md-level-5");
8519 MODULE_ALIAS("md-level-4");
8520 MODULE_ALIAS("md-personality-8"); /* RAID6 */
8521 MODULE_ALIAS("md-raid6");
8522 MODULE_ALIAS("md-level-6");
8523
8524 /* This used to be two separate modules, they were: */
8525 MODULE_ALIAS("raid5");
8526 MODULE_ALIAS("raid6");