drivers/md/raid5.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * raid5.c : Multiple Devices driver for Linux
   4  *         Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
   5  *         Copyright (C) 1999, 2000 Ingo Molnar
   6  *         Copyright (C) 2002, 2003 H. Peter Anvin
   7  *
   8  * RAID-4/5/6 management functions.
   9  * Thanks to Penguin Computing for making the RAID-6 development possible
  10  * by donating a test server!
  11  */
  12
  13 /*
  14  * BITMAP UNPLUGGING:
  15  *
  16  * The sequencing for updating the bitmap reliably is a little
  17  * subtle (and I got it wrong the first time) so it deserves some
  18  * explanation.
  19  *
  20  * We group bitmap updates into batches.  Each batch has a number.
  21  * We may write out several batches at once, but that isn't very important.
  22  * conf->seq_write is the number of the last batch successfully written.
  23  * conf->seq_flush is the number of the last batch that was closed to
  24  *    new additions.
  25  * When we discover that we will need to write to any block in a stripe
  26  * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
  27  * the number of the batch it will be in. This is seq_flush+1.
  28  * When we are ready to do a write, if that batch hasn't been written yet,
  29  *   we plug the array and queue the stripe for later.
  30  * When an unplug happens, we increment bm_flush, thus closing the current
  31  *   batch.
  32  * When we notice that bm_flush > bm_write, we write out all pending updates
  33  * to the bitmap, and advance bm_write to where bm_flush was.
  34  * This may occasionally write a bit out twice, but is sure never to
  35  * miss any bits.
  36  */
  37
  38 #include <linux/blkdev.h>
  39 #include <linux/kthread.h>
  40 #include <linux/raid/pq.h>
  41 #include <linux/async_tx.h>
  42 #include <linux/module.h>
  43 #include <linux/async.h>
  44 #include <linux/seq_file.h>
  45 #include <linux/cpu.h>
  46 #include <linux/slab.h>
  47 #include <linux/ratelimit.h>
  48 #include <linux/nodemask.h>
  49
  50 #include <trace/events/block.h>
  51 #include <linux/list_sort.h>
  52
  53 #include "md.h"
  54 #include "raid5.h"
  55 #include "raid0.h"
  56 #include "md-bitmap.h"
  57 #include "raid5-log.h"
  58
  59 #define UNSUPPORTED_MDDEV_FLAGS (1L << MD_FAILFAST_SUPPORTED)
  60
  61 #define cpu_to_group(cpu) cpu_to_node(cpu)
  62 #define ANY_GROUP NUMA_NO_NODE
  63
  64 static bool devices_handle_discard_safely = false;
  65 module_param(devices_handle_discard_safely, bool, 0644);
  66 MODULE_PARM_DESC(devices_handle_discard_safely,
  67                  "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
  68 static struct workqueue_struct *raid5_wq;
  69
  70 static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
  71 {
  72         int hash = (sect >> STRIPE_SHIFT) & HASH_MASK;
  73         return &conf->stripe_hashtbl[hash];
  74 }
  75
  76 static inline int stripe_hash_locks_hash(sector_t sect)
  77 {
  78         return (sect >> STRIPE_SHIFT) & STRIPE_HASH_LOCKS_MASK;
  79 }
  80
  81 static inline void lock_device_hash_lock(struct r5conf *conf, int hash)
  82 {
  83         spin_lock_irq(conf->hash_locks + hash);
  84         spin_lock(&conf->device_lock);
  85 }
  86
  87 static inline void unlock_device_hash_lock(struct r5conf *conf, int hash)
  88 {
  89         spin_unlock(&conf->device_lock);
  90         spin_unlock_irq(conf->hash_locks + hash);
  91 }
  92
  93 static inline void lock_all_device_hash_locks_irq(struct r5conf *conf)
  94 {
  95         int i;
  96         spin_lock_irq(conf->hash_locks);
  97         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
  98                 spin_lock_nest_lock(conf->hash_locks + i, conf->hash_locks);
  99         spin_lock(&conf->device_lock);
 100 }
 101
 102 static inline void unlock_all_device_hash_locks_irq(struct r5conf *conf)
 103 {
 104         int i;
 105         spin_unlock(&conf->device_lock);
 106         for (i = NR_STRIPE_HASH_LOCKS - 1; i; i--)
 107                 spin_unlock(conf->hash_locks + i);
 108         spin_unlock_irq(conf->hash_locks);
 109 }
 110
 111 /* Find first data disk in a raid6 stripe */
 112 static inline int raid6_d0(struct stripe_head *sh)
 113 {
 114         if (sh->ddf_layout)
 115                 /* ddf always start from first device */
 116                 return 0;
 117         /* md starts just after Q block */
 118         if (sh->qd_idx == sh->disks - 1)
 119                 return 0;
 120         else
 121                 return sh->qd_idx + 1;
 122 }
 123 static inline int raid6_next_disk(int disk, int raid_disks)
 124 {
 125         disk++;
 126         return (disk < raid_disks) ? disk : 0;
 127 }
 128
 129 /* When walking through the disks in a raid5, starting at raid6_d0,
 130  * We need to map each disk to a 'slot', where the data disks are slot
 131  * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
 132  * is raid_disks-1.  This help does that mapping.
 133  */
 134 static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
 135                              int *count, int syndrome_disks)
 136 {
 137         int slot = *count;
 138
 139         if (sh->ddf_layout)
 140                 (*count)++;
 141         if (idx == sh->pd_idx)
 142                 return syndrome_disks;
 143         if (idx == sh->qd_idx)
 144                 return syndrome_disks + 1;
 145         if (!sh->ddf_layout)
 146                 (*count)++;
 147         return slot;
 148 }
 149
 150 static void print_raid5_conf (struct r5conf *conf);
 151
 152 static int stripe_operations_active(struct stripe_head *sh)
 153 {
 154         return sh->check_state || sh->reconstruct_state ||
 155                test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
 156                test_bit(STRIPE_COMPUTE_RUN, &sh->state);
 157 }
 158
 159 static bool stripe_is_lowprio(struct stripe_head *sh)
 160 {
 161         return (test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) ||
 162                 test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) &&
 163                !test_bit(STRIPE_R5C_CACHING, &sh->state);
 164 }
 165
 166 static void raid5_wakeup_stripe_thread(struct stripe_head *sh)
 167 {
 168         struct r5conf *conf = sh->raid_conf;
 169         struct r5worker_group *group;
 170         int thread_cnt;
 171         int i, cpu = sh->cpu;
 172
 173         if (!cpu_online(cpu)) {
 174                 cpu = cpumask_any(cpu_online_mask);
 175                 sh->cpu = cpu;
 176         }
 177
 178         if (list_empty(&sh->lru)) {
 179                 struct r5worker_group *group;
 180                 group = conf->worker_groups + cpu_to_group(cpu);
 181                 if (stripe_is_lowprio(sh))
 182                         list_add_tail(&sh->lru, &group->loprio_list);
 183                 else
 184                         list_add_tail(&sh->lru, &group->handle_list);
 185                 group->stripes_cnt++;
 186                 sh->group = group;
 187         }
 188
 189         if (conf->worker_cnt_per_group == 0) {
 190                 md_wakeup_thread(conf->mddev->thread);
 191                 return;
 192         }
 193
 194         group = conf->worker_groups + cpu_to_group(sh->cpu);
 195
 196         group->workers[0].working = true;
 197         /* at least one worker should run to avoid race */
 198         queue_work_on(sh->cpu, raid5_wq, &group->workers[0].work);
 199
 200         thread_cnt = group->stripes_cnt / MAX_STRIPE_BATCH - 1;
 201         /* wakeup more workers */
 202         for (i = 1; i < conf->worker_cnt_per_group && thread_cnt > 0; i++) {
 203                 if (group->workers[i].working == false) {
 204                         group->workers[i].working = true;
 205                         queue_work_on(sh->cpu, raid5_wq,
 206                                       &group->workers[i].work);
 207                         thread_cnt--;
 208                 }
 209         }
 210 }
 211
 212 static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh,
 213                               struct list_head *temp_inactive_list)
 214 {
 215         int i;
 216         int injournal = 0;      /* number of date pages with R5_InJournal */
 217
 218         BUG_ON(!list_empty(&sh->lru));
 219         BUG_ON(atomic_read(&conf->active_stripes)==0);
 220
 221         if (r5c_is_writeback(conf->log))
 222                 for (i = sh->disks; i--; )
 223                         if (test_bit(R5_InJournal, &sh->dev[i].flags))
 224                                 injournal++;
 225         /*
 226          * In the following cases, the stripe cannot be released to cached
 227          * lists. Therefore, we make the stripe write out and set
 228          * STRIPE_HANDLE:
 229          *   1. when quiesce in r5c write back;
 230          *   2. when resync is requested fot the stripe.
 231          */
 232         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) ||
 233             (conf->quiesce && r5c_is_writeback(conf->log) &&
 234              !test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0)) {
 235                 if (test_bit(STRIPE_R5C_CACHING, &sh->state))
 236                         r5c_make_stripe_write_out(sh);
 237                 set_bit(STRIPE_HANDLE, &sh->state);
 238         }
 239
 240         if (test_bit(STRIPE_HANDLE, &sh->state)) {
 241                 if (test_bit(STRIPE_DELAYED, &sh->state) &&
 242                     !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 243                         list_add_tail(&sh->lru, &conf->delayed_list);
 244                 else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
 245                            sh->bm_seq - conf->seq_write > 0)
 246                         list_add_tail(&sh->lru, &conf->bitmap_list);
 247                 else {
 248                         clear_bit(STRIPE_DELAYED, &sh->state);
 249                         clear_bit(STRIPE_BIT_DELAY, &sh->state);
 250                         if (conf->worker_cnt_per_group == 0) {
 251                                 if (stripe_is_lowprio(sh))
 252                                         list_add_tail(&sh->lru,
 253                                                         &conf->loprio_list);
 254                                 else
 255                                         list_add_tail(&sh->lru,
 256                                                         &conf->handle_list);
 257                         } else {
 258                                 raid5_wakeup_stripe_thread(sh);
 259                                 return;
 260                         }
 261                 }
 262                 md_wakeup_thread(conf->mddev->thread);
 263         } else {
 264                 BUG_ON(stripe_operations_active(sh));
 265                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 266                         if (atomic_dec_return(&conf->preread_active_stripes)
 267                             < IO_THRESHOLD)
 268                                 md_wakeup_thread(conf->mddev->thread);
 269                 atomic_dec(&conf->active_stripes);
 270                 if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
 271                         if (!r5c_is_writeback(conf->log))
 272                                 list_add_tail(&sh->lru, temp_inactive_list);
 273                         else {
 274                                 WARN_ON(test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags));
 275                                 if (injournal == 0)
 276                                         list_add_tail(&sh->lru, temp_inactive_list);
 277                                 else if (injournal == conf->raid_disks - conf->max_degraded) {
 278                                         /* full stripe */
 279                                         if (!test_and_set_bit(STRIPE_R5C_FULL_STRIPE, &sh->state))
 280                                                 atomic_inc(&conf->r5c_cached_full_stripes);
 281                                         if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
 282                                                 atomic_dec(&conf->r5c_cached_partial_stripes);
 283                                         list_add_tail(&sh->lru, &conf->r5c_full_stripe_list);
 284                                         r5c_check_cached_full_stripe(conf);
 285                                 } else
 286                                         /*
 287                                          * STRIPE_R5C_PARTIAL_STRIPE is set in
 288                                          * r5c_try_caching_write(). No need to
 289                                          * set it again.
 290                                          */
 291                                         list_add_tail(&sh->lru, &conf->r5c_partial_stripe_list);
 292                         }
 293                 }
 294         }
 295 }
 296
 297 static void __release_stripe(struct r5conf *conf, struct stripe_head *sh,
 298                              struct list_head *temp_inactive_list)
 299 {
 300         if (atomic_dec_and_test(&sh->count))
 301                 do_release_stripe(conf, sh, temp_inactive_list);
 302 }
 303
 304 /*
 305  * @hash could be NR_STRIPE_HASH_LOCKS, then we have a list of inactive_list
 306  *
 307  * Be careful: Only one task can add/delete stripes from temp_inactive_list at
 308  * given time. Adding stripes only takes device lock, while deleting stripes
 309  * only takes hash lock.
 310  */
 311 static void release_inactive_stripe_list(struct r5conf *conf,
 312                                          struct list_head *temp_inactive_list,
 313                                          int hash)
 314 {
 315         int size;
 316         bool do_wakeup = false;
 317         unsigned long flags;
 318
 319         if (hash == NR_STRIPE_HASH_LOCKS) {
 320                 size = NR_STRIPE_HASH_LOCKS;
 321                 hash = NR_STRIPE_HASH_LOCKS - 1;
 322         } else
 323                 size = 1;
 324         while (size) {
 325                 struct list_head *list = &temp_inactive_list[size - 1];
 326
 327                 /*
 328                  * We don't hold any lock here yet, raid5_get_active_stripe() might
 329                  * remove stripes from the list
 330                  */
 331                 if (!list_empty_careful(list)) {
 332                         spin_lock_irqsave(conf->hash_locks + hash, flags);
 333                         if (list_empty(conf->inactive_list + hash) &&
 334                             !list_empty(list))
 335                                 atomic_dec(&conf->empty_inactive_list_nr);
 336                         list_splice_tail_init(list, conf->inactive_list + hash);
 337                         do_wakeup = true;
 338                         spin_unlock_irqrestore(conf->hash_locks + hash, flags);
 339                 }
 340                 size--;
 341                 hash--;
 342         }
 343
 344         if (do_wakeup) {
 345                 wake_up(&conf->wait_for_stripe);
 346                 if (atomic_read(&conf->active_stripes) == 0)
 347                         wake_up(&conf->wait_for_quiescent);
 348                 if (conf->retry_read_aligned)
 349                         md_wakeup_thread(conf->mddev->thread);
 350         }
 351 }
 352
 353 /* should hold conf->device_lock already */
 354 static int release_stripe_list(struct r5conf *conf,
 355                                struct list_head *temp_inactive_list)
 356 {
 357         struct stripe_head *sh, *t;
 358         int count = 0;
 359         struct llist_node *head;
 360
 361         head = llist_del_all(&conf->released_stripes);
 362         head = llist_reverse_order(head);
 363         llist_for_each_entry_safe(sh, t, head, release_list) {
 364                 int hash;
 365
 366                 /* sh could be readded after STRIPE_ON_RELEASE_LIST is cleard */
 367                 smp_mb();
 368                 clear_bit(STRIPE_ON_RELEASE_LIST, &sh->state);
 369                 /*
 370                  * Don't worry the bit is set here, because if the bit is set
 371                  * again, the count is always > 1. This is true for
 372                  * STRIPE_ON_UNPLUG_LIST bit too.
 373                  */
 374                 hash = sh->hash_lock_index;
 375                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
 376                 count++;
 377         }
 378
 379         return count;
 380 }
 381
 382 void raid5_release_stripe(struct stripe_head *sh)
 383 {
 384         struct r5conf *conf = sh->raid_conf;
 385         unsigned long flags;
 386         struct list_head list;
 387         int hash;
 388         bool wakeup;
 389
 390         /* Avoid release_list until the last reference.
 391          */
 392         if (atomic_add_unless(&sh->count, -1, 1))
 393                 return;
 394
 395         if (unlikely(!conf->mddev->thread) ||
 396                 test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state))
 397                 goto slow_path;
 398         wakeup = llist_add(&sh->release_list, &conf->released_stripes);
 399         if (wakeup)
 400                 md_wakeup_thread(conf->mddev->thread);
 401         return;
 402 slow_path:
 403         /* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */
 404         if (atomic_dec_and_lock_irqsave(&sh->count, &conf->device_lock, flags)) {
 405                 INIT_LIST_HEAD(&list);
 406                 hash = sh->hash_lock_index;
 407                 do_release_stripe(conf, sh, &list);
 408                 spin_unlock_irqrestore(&conf->device_lock, flags);
 409                 release_inactive_stripe_list(conf, &list, hash);
 410         }
 411 }
 412
 413 static inline void remove_hash(struct stripe_head *sh)
 414 {
 415         pr_debug("remove_hash(), stripe %llu\n",
 416                 (unsigned long long)sh->sector);
 417
 418         hlist_del_init(&sh->hash);
 419 }
 420
 421 static inline void insert_hash(struct r5conf *conf, struct stripe_head *sh)
 422 {
 423         struct hlist_head *hp = stripe_hash(conf, sh->sector);
 424
 425         pr_debug("insert_hash(), stripe %llu\n",
 426                 (unsigned long long)sh->sector);
 427
 428         hlist_add_head(&sh->hash, hp);
 429 }
 430
 431 /* find an idle stripe, make sure it is unhashed, and return it. */
 432 static struct stripe_head *get_free_stripe(struct r5conf *conf, int hash)
 433 {
 434         struct stripe_head *sh = NULL;
 435         struct list_head *first;
 436
 437         if (list_empty(conf->inactive_list + hash))
 438                 goto out;
 439         first = (conf->inactive_list + hash)->next;
 440         sh = list_entry(first, struct stripe_head, lru);
 441         list_del_init(first);
 442         remove_hash(sh);
 443         atomic_inc(&conf->active_stripes);
 444         BUG_ON(hash != sh->hash_lock_index);
 445         if (list_empty(conf->inactive_list + hash))
 446                 atomic_inc(&conf->empty_inactive_list_nr);
 447 out:
 448         return sh;
 449 }
 450
 451 static void shrink_buffers(struct stripe_head *sh)
 452 {
 453         struct page *p;
 454         int i;
 455         int num = sh->raid_conf->pool_size;
 456
 457         for (i = 0; i < num ; i++) {
 458                 WARN_ON(sh->dev[i].page != sh->dev[i].orig_page);
 459                 p = sh->dev[i].page;
 460                 if (!p)
 461                         continue;
 462                 sh->dev[i].page = NULL;
 463                 put_page(p);
 464         }
 465 }
 466
 467 static int grow_buffers(struct stripe_head *sh, gfp_t gfp)
 468 {
 469         int i;
 470         int num = sh->raid_conf->pool_size;
 471
 472         for (i = 0; i < num; i++) {
 473                 struct page *page;
 474
 475                 if (!(page = alloc_page(gfp))) {
 476                         return 1;
 477                 }
 478                 sh->dev[i].page = page;
 479                 sh->dev[i].orig_page = page;
 480         }
 481
 482         return 0;
 483 }
 484
 485 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
 486                             struct stripe_head *sh);
 487
 488 static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
 489 {
 490         struct r5conf *conf = sh->raid_conf;
 491         int i, seq;
 492
 493         BUG_ON(atomic_read(&sh->count) != 0);
 494         BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
 495         BUG_ON(stripe_operations_active(sh));
 496         BUG_ON(sh->batch_head);
 497
 498         pr_debug("init_stripe called, stripe %llu\n",
 499                 (unsigned long long)sector);
 500 retry:
 501         seq = read_seqcount_begin(&conf->gen_lock);
 502         sh->generation = conf->generation - previous;
 503         sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
 504         sh->sector = sector;
 505         stripe_set_idx(sector, conf, previous, sh);
 506         sh->state = 0;
 507
 508         for (i = sh->disks; i--; ) {
 509                 struct r5dev *dev = &sh->dev[i];
 510
 511                 if (dev->toread || dev->read || dev->towrite || dev->written ||
 512                     test_bit(R5_LOCKED, &dev->flags)) {
 513                         pr_err("sector=%llx i=%d %p %p %p %p %d\n",
 514                                (unsigned long long)sh->sector, i, dev->toread,
 515                                dev->read, dev->towrite, dev->written,
 516                                test_bit(R5_LOCKED, &dev->flags));
 517                         WARN_ON(1);
 518                 }
 519                 dev->flags = 0;
 520                 dev->sector = raid5_compute_blocknr(sh, i, previous);
 521         }
 522         if (read_seqcount_retry(&conf->gen_lock, seq))
 523                 goto retry;
 524         sh->overwrite_disks = 0;
 525         insert_hash(conf, sh);
 526         sh->cpu = smp_processor_id();
 527         set_bit(STRIPE_BATCH_READY, &sh->state);
 528 }
 529
 530 static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
 531                                          short generation)
 532 {
 533         struct stripe_head *sh;
 534
 535         pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
 536         hlist_for_each_entry(sh, stripe_hash(conf, sector), hash)
 537                 if (sh->sector == sector && sh->generation == generation)
 538                         return sh;
 539         pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
 540         return NULL;
 541 }
 542
 543 /*
 544  * Need to check if array has failed when deciding whether to:
 545  *  - start an array
 546  *  - remove non-faulty devices
 547  *  - add a spare
 548  *  - allow a reshape
 549  * This determination is simple when no reshape is happening.
 550  * However if there is a reshape, we need to carefully check
 551  * both the before and after sections.
 552  * This is because some failed devices may only affect one
 553  * of the two sections, and some non-in_sync devices may
 554  * be insync in the section most affected by failed devices.
 555  */
 556 int raid5_calc_degraded(struct r5conf *conf)
 557 {
 558         int degraded, degraded2;
 559         int i;
 560
 561         rcu_read_lock();
 562         degraded = 0;
 563         for (i = 0; i < conf->previous_raid_disks; i++) {
 564                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 565                 if (rdev && test_bit(Faulty, &rdev->flags))
 566                         rdev = rcu_dereference(conf->disks[i].replacement);
 567                 if (!rdev || test_bit(Faulty, &rdev->flags))
 568                         degraded++;
 569                 else if (test_bit(In_sync, &rdev->flags))
 570                         ;
 571                 else
 572                         /* not in-sync or faulty.
 573                          * If the reshape increases the number of devices,
 574                          * this is being recovered by the reshape, so
 575                          * this 'previous' section is not in_sync.
 576                          * If the number of devices is being reduced however,
 577                          * the device can only be part of the array if
 578                          * we are reverting a reshape, so this section will
 579                          * be in-sync.
 580                          */
 581                         if (conf->raid_disks >= conf->previous_raid_disks)
 582                                 degraded++;
 583         }
 584         rcu_read_unlock();
 585         if (conf->raid_disks == conf->previous_raid_disks)
 586                 return degraded;
 587         rcu_read_lock();
 588         degraded2 = 0;
 589         for (i = 0; i < conf->raid_disks; i++) {
 590                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 591                 if (rdev && test_bit(Faulty, &rdev->flags))
 592                         rdev = rcu_dereference(conf->disks[i].replacement);
 593                 if (!rdev || test_bit(Faulty, &rdev->flags))
 594                         degraded2++;
 595                 else if (test_bit(In_sync, &rdev->flags))
 596                         ;
 597                 else
 598                         /* not in-sync or faulty.
 599                          * If reshape increases the number of devices, this
 600                          * section has already been recovered, else it
 601                          * almost certainly hasn't.
 602                          */
 603                         if (conf->raid_disks <= conf->previous_raid_disks)
 604                                 degraded2++;
 605         }
 606         rcu_read_unlock();
 607         if (degraded2 > degraded)
 608                 return degraded2;
 609         return degraded;
 610 }
 611
 612 static int has_failed(struct r5conf *conf)
 613 {
 614         int degraded;
 615
 616         if (conf->mddev->reshape_position == MaxSector)
 617                 return conf->mddev->degraded > conf->max_degraded;
 618
 619         degraded = raid5_calc_degraded(conf);
 620         if (degraded > conf->max_degraded)
 621                 return 1;
 622         return 0;
 623 }
 624
 625 struct stripe_head *
 626 raid5_get_active_stripe(struct r5conf *conf, sector_t sector,
 627                         int previous, int noblock, int noquiesce)
 628 {
 629         struct stripe_head *sh;
 630         int hash = stripe_hash_locks_hash(sector);
 631         int inc_empty_inactive_list_flag;
 632
 633         pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
 634
 635         spin_lock_irq(conf->hash_locks + hash);
 636
 637         do {
 638                 wait_event_lock_irq(conf->wait_for_quiescent,
 639                                     conf->quiesce == 0 || noquiesce,
 640                                     *(conf->hash_locks + hash));
 641                 sh = __find_stripe(conf, sector, conf->generation - previous);
 642                 if (!sh) {
 643                         if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state)) {
 644                                 sh = get_free_stripe(conf, hash);
 645                                 if (!sh && !test_bit(R5_DID_ALLOC,
 646                                                      &conf->cache_state))
 647                                         set_bit(R5_ALLOC_MORE,
 648                                                 &conf->cache_state);
 649                         }
 650                         if (noblock && sh == NULL)
 651                                 break;
 652
 653                         r5c_check_stripe_cache_usage(conf);
 654                         if (!sh) {
 655                                 set_bit(R5_INACTIVE_BLOCKED,
 656                                         &conf->cache_state);
 657                                 r5l_wake_reclaim(conf->log, 0);
 658                                 wait_event_lock_irq(
 659                                         conf->wait_for_stripe,
 660                                         !list_empty(conf->inactive_list + hash) &&
 661                                         (atomic_read(&conf->active_stripes)
 662                                          < (conf->max_nr_stripes * 3 / 4)
 663                                          || !test_bit(R5_INACTIVE_BLOCKED,
 664                                                       &conf->cache_state)),
 665                                         *(conf->hash_locks + hash));
 666                                 clear_bit(R5_INACTIVE_BLOCKED,
 667                                           &conf->cache_state);
 668                         } else {
 669                                 init_stripe(sh, sector, previous);
 670                                 atomic_inc(&sh->count);
 671                         }
 672                 } else if (!atomic_inc_not_zero(&sh->count)) {
 673                         spin_lock(&conf->device_lock);
 674                         if (!atomic_read(&sh->count)) {
 675                                 if (!test_bit(STRIPE_HANDLE, &sh->state))
 676                                         atomic_inc(&conf->active_stripes);
 677                                 BUG_ON(list_empty(&sh->lru) &&
 678                                        !test_bit(STRIPE_EXPANDING, &sh->state));
 679                                 inc_empty_inactive_list_flag = 0;
 680                                 if (!list_empty(conf->inactive_list + hash))
 681                                         inc_empty_inactive_list_flag = 1;
 682                                 list_del_init(&sh->lru);
 683                                 if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 684                                         atomic_inc(&conf->empty_inactive_list_nr);
 685                                 if (sh->group) {
 686                                         sh->group->stripes_cnt--;
 687                                         sh->group = NULL;
 688                                 }
 689                         }
 690                         atomic_inc(&sh->count);
 691                         spin_unlock(&conf->device_lock);
 692                 }
 693         } while (sh == NULL);
 694
 695         spin_unlock_irq(conf->hash_locks + hash);
 696         return sh;
 697 }
 698
 699 static bool is_full_stripe_write(struct stripe_head *sh)
 700 {
 701         BUG_ON(sh->overwrite_disks > (sh->disks - sh->raid_conf->max_degraded));
 702         return sh->overwrite_disks == (sh->disks - sh->raid_conf->max_degraded);
 703 }
 704
 705 static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 706                 __acquires(&sh1->stripe_lock)
 707                 __acquires(&sh2->stripe_lock)
 708 {
 709         if (sh1 > sh2) {
 710                 spin_lock_irq(&sh2->stripe_lock);
 711                 spin_lock_nested(&sh1->stripe_lock, 1);
 712         } else {
 713                 spin_lock_irq(&sh1->stripe_lock);
 714                 spin_lock_nested(&sh2->stripe_lock, 1);
 715         }
 716 }
 717
 718 static void unlock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 719                 __releases(&sh1->stripe_lock)
 720                 __releases(&sh2->stripe_lock)
 721 {
 722         spin_unlock(&sh1->stripe_lock);
 723         spin_unlock_irq(&sh2->stripe_lock);
 724 }
 725
 726 /* Only freshly new full stripe normal write stripe can be added to a batch list */
 727 static bool stripe_can_batch(struct stripe_head *sh)
 728 {
 729         struct r5conf *conf = sh->raid_conf;
 730
 731         if (raid5_has_log(conf) || raid5_has_ppl(conf))
 732                 return false;
 733         return test_bit(STRIPE_BATCH_READY, &sh->state) &&
 734                 !test_bit(STRIPE_BITMAP_PENDING, &sh->state) &&
 735                 is_full_stripe_write(sh);
 736 }
 737
 738 /* we only do back search */
 739 static void stripe_add_to_batch_list(struct r5conf *conf, struct stripe_head *sh)
 740 {
 741         struct stripe_head *head;
 742         sector_t head_sector, tmp_sec;
 743         int hash;
 744         int dd_idx;
 745         int inc_empty_inactive_list_flag;
 746
 747         /* Don't cross chunks, so stripe pd_idx/qd_idx is the same */
 748         tmp_sec = sh->sector;
 749         if (!sector_div(tmp_sec, conf->chunk_sectors))
 750                 return;
 751         head_sector = sh->sector - STRIPE_SECTORS;
 752
 753         hash = stripe_hash_locks_hash(head_sector);
 754         spin_lock_irq(conf->hash_locks + hash);
 755         head = __find_stripe(conf, head_sector, conf->generation);
 756         if (head && !atomic_inc_not_zero(&head->count)) {
 757                 spin_lock(&conf->device_lock);
 758                 if (!atomic_read(&head->count)) {
 759                         if (!test_bit(STRIPE_HANDLE, &head->state))
 760                                 atomic_inc(&conf->active_stripes);
 761                         BUG_ON(list_empty(&head->lru) &&
 762                                !test_bit(STRIPE_EXPANDING, &head->state));
 763                         inc_empty_inactive_list_flag = 0;
 764                         if (!list_empty(conf->inactive_list + hash))
 765                                 inc_empty_inactive_list_flag = 1;
 766                         list_del_init(&head->lru);
 767                         if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 768                                 atomic_inc(&conf->empty_inactive_list_nr);
 769                         if (head->group) {
 770                                 head->group->stripes_cnt--;
 771                                 head->group = NULL;
 772                         }
 773                 }
 774                 atomic_inc(&head->count);
 775                 spin_unlock(&conf->device_lock);
 776         }
 777         spin_unlock_irq(conf->hash_locks + hash);
 778
 779         if (!head)
 780                 return;
 781         if (!stripe_can_batch(head))
 782                 goto out;
 783
 784         lock_two_stripes(head, sh);
 785         /* clear_batch_ready clear the flag */
 786         if (!stripe_can_batch(head) || !stripe_can_batch(sh))
 787                 goto unlock_out;
 788
 789         if (sh->batch_head)
 790                 goto unlock_out;
 791
 792         dd_idx = 0;
 793         while (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
 794                 dd_idx++;
 795         if (head->dev[dd_idx].towrite->bi_opf != sh->dev[dd_idx].towrite->bi_opf ||
 796             bio_op(head->dev[dd_idx].towrite) != bio_op(sh->dev[dd_idx].towrite))
 797                 goto unlock_out;
 798
 799         if (head->batch_head) {
 800                 spin_lock(&head->batch_head->batch_lock);
 801                 /* This batch list is already running */
 802                 if (!stripe_can_batch(head)) {
 803                         spin_unlock(&head->batch_head->batch_lock);
 804                         goto unlock_out;
 805                 }
 806                 /*
 807                  * We must assign batch_head of this stripe within the
 808                  * batch_lock, otherwise clear_batch_ready of batch head
 809                  * stripe could clear BATCH_READY bit of this stripe and
 810                  * this stripe->batch_head doesn't get assigned, which
 811                  * could confuse clear_batch_ready for this stripe
 812                  */
 813                 sh->batch_head = head->batch_head;
 814
 815                 /*
 816                  * at this point, head's BATCH_READY could be cleared, but we
 817                  * can still add the stripe to batch list
 818                  */
 819                 list_add(&sh->batch_list, &head->batch_list);
 820                 spin_unlock(&head->batch_head->batch_lock);
 821         } else {
 822                 head->batch_head = head;
 823                 sh->batch_head = head->batch_head;
 824                 spin_lock(&head->batch_lock);
 825                 list_add_tail(&sh->batch_list, &head->batch_list);
 826                 spin_unlock(&head->batch_lock);
 827         }
 828
 829         if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 830                 if (atomic_dec_return(&conf->preread_active_stripes)
 831                     < IO_THRESHOLD)
 832                         md_wakeup_thread(conf->mddev->thread);
 833
 834         if (test_and_clear_bit(STRIPE_BIT_DELAY, &sh->state)) {
 835                 int seq = sh->bm_seq;
 836                 if (test_bit(STRIPE_BIT_DELAY, &sh->batch_head->state) &&
 837                     sh->batch_head->bm_seq > seq)
 838                         seq = sh->batch_head->bm_seq;
 839                 set_bit(STRIPE_BIT_DELAY, &sh->batch_head->state);
 840                 sh->batch_head->bm_seq = seq;
 841         }
 842
 843         atomic_inc(&sh->count);
 844 unlock_out:
 845         unlock_two_stripes(head, sh);
 846 out:
 847         raid5_release_stripe(head);
 848 }
 849
 850 /* Determine if 'data_offset' or 'new_data_offset' should be used
 851  * in this stripe_head.
 852  */
 853 static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
 854 {
 855         sector_t progress = conf->reshape_progress;
 856         /* Need a memory barrier to make sure we see the value
 857          * of conf->generation, or ->data_offset that was set before
 858          * reshape_progress was updated.
 859          */
 860         smp_rmb();
 861         if (progress == MaxSector)
 862                 return 0;
 863         if (sh->generation == conf->generation - 1)
 864                 return 0;
 865         /* We are in a reshape, and this is a new-generation stripe,
 866          * so use new_data_offset.
 867          */
 868         return 1;
 869 }
 870
 871 static void dispatch_bio_list(struct bio_list *tmp)
 872 {
 873         struct bio *bio;
 874
 875         while ((bio = bio_list_pop(tmp)))
 876                 generic_make_request(bio);
 877 }
 878
 879 static int cmp_stripe(void *priv, struct list_head *a, struct list_head *b)
 880 {
 881         const struct r5pending_data *da = list_entry(a,
 882                                 struct r5pending_data, sibling);
 883         const struct r5pending_data *db = list_entry(b,
 884                                 struct r5pending_data, sibling);
 885         if (da->sector > db->sector)
 886                 return 1;
 887         if (da->sector < db->sector)
 888                 return -1;
 889         return 0;
 890 }
 891
 892 static void dispatch_defer_bios(struct r5conf *conf, int target,
 893                                 struct bio_list *list)
 894 {
 895         struct r5pending_data *data;
 896         struct list_head *first, *next = NULL;
 897         int cnt = 0;
 898
 899         if (conf->pending_data_cnt == 0)
 900                 return;
 901
 902         list_sort(NULL, &conf->pending_list, cmp_stripe);
 903
 904         first = conf->pending_list.next;
 905
 906         /* temporarily move the head */
 907         if (conf->next_pending_data)
 908                 list_move_tail(&conf->pending_list,
 909                                 &conf->next_pending_data->sibling);
 910
 911         while (!list_empty(&conf->pending_list)) {
 912                 data = list_first_entry(&conf->pending_list,
 913                         struct r5pending_data, sibling);
 914                 if (&data->sibling == first)
 915                         first = data->sibling.next;
 916                 next = data->sibling.next;
 917
 918                 bio_list_merge(list, &data->bios);
 919                 list_move(&data->sibling, &conf->free_list);
 920                 cnt++;
 921                 if (cnt >= target)
 922                         break;
 923         }
 924         conf->pending_data_cnt -= cnt;
 925         BUG_ON(conf->pending_data_cnt < 0 || cnt < target);
 926
 927         if (next != &conf->pending_list)
 928                 conf->next_pending_data = list_entry(next,
 929                                 struct r5pending_data, sibling);
 930         else
 931                 conf->next_pending_data = NULL;
 932         /* list isn't empty */
 933         if (first != &conf->pending_list)
 934                 list_move_tail(&conf->pending_list, first);
 935 }
 936
 937 static void flush_deferred_bios(struct r5conf *conf)
 938 {
 939         struct bio_list tmp = BIO_EMPTY_LIST;
 940
 941         if (conf->pending_data_cnt == 0)
 942                 return;
 943
 944         spin_lock(&conf->pending_bios_lock);
 945         dispatch_defer_bios(conf, conf->pending_data_cnt, &tmp);
 946         BUG_ON(conf->pending_data_cnt != 0);
 947         spin_unlock(&conf->pending_bios_lock);
 948
 949         dispatch_bio_list(&tmp);
 950 }
 951
 952 static void defer_issue_bios(struct r5conf *conf, sector_t sector,
 953                                 struct bio_list *bios)
 954 {
 955         struct bio_list tmp = BIO_EMPTY_LIST;
 956         struct r5pending_data *ent;
 957
 958         spin_lock(&conf->pending_bios_lock);
 959         ent = list_first_entry(&conf->free_list, struct r5pending_data,
 960                                                         sibling);
 961         list_move_tail(&ent->sibling, &conf->pending_list);
 962         ent->sector = sector;
 963         bio_list_init(&ent->bios);
 964         bio_list_merge(&ent->bios, bios);
 965         conf->pending_data_cnt++;
 966         if (conf->pending_data_cnt >= PENDING_IO_MAX)
 967                 dispatch_defer_bios(conf, PENDING_IO_ONE_FLUSH, &tmp);
 968
 969         spin_unlock(&conf->pending_bios_lock);
 970
 971         dispatch_bio_list(&tmp);
 972 }
 973
 974 static void
 975 raid5_end_read_request(struct bio *bi);
 976 static void
 977 raid5_end_write_request(struct bio *bi);
 978
 979 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 980 {
 981         struct r5conf *conf = sh->raid_conf;
 982         int i, disks = sh->disks;
 983         struct stripe_head *head_sh = sh;
 984         struct bio_list pending_bios = BIO_EMPTY_LIST;
 985         bool should_defer;
 986
 987         might_sleep();
 988
 989         if (log_stripe(sh, s) == 0)
 990                 return;
 991
 992         should_defer = conf->batch_bio_dispatch && conf->group_cnt;
 993
 994         for (i = disks; i--; ) {
 995                 int op, op_flags = 0;
 996                 int replace_only = 0;
 997                 struct bio *bi, *rbi;
 998                 struct md_rdev *rdev, *rrdev = NULL;
 999
1000                 sh = head_sh;
1001                 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
1002                         op = REQ_OP_WRITE;
1003                         if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
1004                                 op_flags = REQ_FUA;
1005                         if (test_bit(R5_Discard, &sh->dev[i].flags))
1006                                 op = REQ_OP_DISCARD;
1007                 } else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1008                         op = REQ_OP_READ;
1009                 else if (test_and_clear_bit(R5_WantReplace,
1010                                             &sh->dev[i].flags)) {
1011                         op = REQ_OP_WRITE;
1012                         replace_only = 1;
1013                 } else
1014                         continue;
1015                 if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
1016                         op_flags |= REQ_SYNC;
1017
1018 again:
1019                 bi = &sh->dev[i].req;
1020                 rbi = &sh->dev[i].rreq; /* For writing to replacement */
1021
1022                 rcu_read_lock();
1023                 rrdev = rcu_dereference(conf->disks[i].replacement);
1024                 smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
1025                 rdev = rcu_dereference(conf->disks[i].rdev);
1026                 if (!rdev) {
1027                         rdev = rrdev;
1028                         rrdev = NULL;
1029                 }
1030                 if (op_is_write(op)) {
1031                         if (replace_only)
1032                                 rdev = NULL;
1033                         if (rdev == rrdev)
1034                                 /* We raced and saw duplicates */
1035                                 rrdev = NULL;
1036                 } else {
1037                         if (test_bit(R5_ReadRepl, &head_sh->dev[i].flags) && rrdev)
1038                                 rdev = rrdev;
1039                         rrdev = NULL;
1040                 }
1041
1042                 if (rdev && test_bit(Faulty, &rdev->flags))
1043                         rdev = NULL;
1044                 if (rdev)
1045                         atomic_inc(&rdev->nr_pending);
1046                 if (rrdev && test_bit(Faulty, &rrdev->flags))
1047                         rrdev = NULL;
1048                 if (rrdev)
1049                         atomic_inc(&rrdev->nr_pending);
1050                 rcu_read_unlock();
1051
1052                 /* We have already checked bad blocks for reads.  Now
1053                  * need to check for writes.  We never accept write errors
1054                  * on the replacement, so we don't to check rrdev.
1055                  */
1056                 while (op_is_write(op) && rdev &&
1057                        test_bit(WriteErrorSeen, &rdev->flags)) {
1058                         sector_t first_bad;
1059                         int bad_sectors;
1060                         int bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
1061                                               &first_bad, &bad_sectors);
1062                         if (!bad)
1063                                 break;
1064
1065                         if (bad < 0) {
1066                                 set_bit(BlockedBadBlocks, &rdev->flags);
1067                                 if (!conf->mddev->external &&
1068                                     conf->mddev->sb_flags) {
1069                                         /* It is very unlikely, but we might
1070                                          * still need to write out the
1071                                          * bad block log - better give it
1072                                          * a chance*/
1073                                         md_check_recovery(conf->mddev);
1074                                 }
1075                                 /*
1076                                  * Because md_wait_for_blocked_rdev
1077                                  * will dec nr_pending, we must
1078                                  * increment it first.
1079                                  */
1080                                 atomic_inc(&rdev->nr_pending);
1081                                 md_wait_for_blocked_rdev(rdev, conf->mddev);
1082                         } else {
1083                                 /* Acknowledged bad block - skip the write */
1084                                 rdev_dec_pending(rdev, conf->mddev);
1085                                 rdev = NULL;
1086                         }
1087                 }
1088
1089                 if (rdev) {
1090                         if (s->syncing || s->expanding || s->expanded
1091                             || s->replacing)
1092                                 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
1093
1094                         set_bit(STRIPE_IO_STARTED, &sh->state);
1095
1096                         bio_set_dev(bi, rdev->bdev);
1097                         bio_set_op_attrs(bi, op, op_flags);
1098                         bi->bi_end_io = op_is_write(op)
1099                                 ? raid5_end_write_request
1100                                 : raid5_end_read_request;
1101                         bi->bi_private = sh;
1102
1103                         pr_debug("%s: for %llu schedule op %d on disc %d\n",
1104                                 __func__, (unsigned long long)sh->sector,
1105                                 bi->bi_opf, i);
1106                         atomic_inc(&sh->count);
1107                         if (sh != head_sh)
1108                                 atomic_inc(&head_sh->count);
1109                         if (use_new_offset(conf, sh))
1110                                 bi->bi_iter.bi_sector = (sh->sector
1111                                                  + rdev->new_data_offset);
1112                         else
1113                                 bi->bi_iter.bi_sector = (sh->sector
1114                                                  + rdev->data_offset);
1115                         if (test_bit(R5_ReadNoMerge, &head_sh->dev[i].flags))
1116                                 bi->bi_opf |= REQ_NOMERGE;
1117
1118                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1119                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1120
1121                         if (!op_is_write(op) &&
1122                             test_bit(R5_InJournal, &sh->dev[i].flags))
1123                                 /*
1124                                  * issuing read for a page in journal, this
1125                                  * must be preparing for prexor in rmw; read
1126                                  * the data into orig_page
1127                                  */
1128                                 sh->dev[i].vec.bv_page = sh->dev[i].orig_page;
1129                         else
1130                                 sh->dev[i].vec.bv_page = sh->dev[i].page;
1131                         bi->bi_vcnt = 1;
1132                         bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1133                         bi->bi_io_vec[0].bv_offset = 0;
1134                         bi->bi_iter.bi_size = STRIPE_SIZE;
1135                         bi->bi_write_hint = sh->dev[i].write_hint;
1136                         if (!rrdev)
1137                                 sh->dev[i].write_hint = RWF_WRITE_LIFE_NOT_SET;
1138                         /*
1139                          * If this is discard request, set bi_vcnt 0. We don't
1140                          * want to confuse SCSI because SCSI will replace payload
1141                          */
1142                         if (op == REQ_OP_DISCARD)
1143                                 bi->bi_vcnt = 0;
1144                         if (rrdev)
1145                                 set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
1146
1147                         if (conf->mddev->gendisk)
1148                                 trace_block_bio_remap(bi->bi_disk->queue,
1149                                                       bi, disk_devt(conf->mddev->gendisk),
1150                                                       sh->dev[i].sector);
1151                         if (should_defer && op_is_write(op))
1152                                 bio_list_add(&pending_bios, bi);
1153                         else
1154                                 generic_make_request(bi);
1155                 }
1156                 if (rrdev) {
1157                         if (s->syncing || s->expanding || s->expanded
1158                             || s->replacing)
1159                                 md_sync_acct(rrdev->bdev, STRIPE_SECTORS);
1160
1161                         set_bit(STRIPE_IO_STARTED, &sh->state);
1162
1163                         bio_set_dev(rbi, rrdev->bdev);
1164                         bio_set_op_attrs(rbi, op, op_flags);
1165                         BUG_ON(!op_is_write(op));
1166                         rbi->bi_end_io = raid5_end_write_request;
1167                         rbi->bi_private = sh;
1168
1169                         pr_debug("%s: for %llu schedule op %d on "
1170                                  "replacement disc %d\n",
1171                                 __func__, (unsigned long long)sh->sector,
1172                                 rbi->bi_opf, i);
1173                         atomic_inc(&sh->count);
1174                         if (sh != head_sh)
1175                                 atomic_inc(&head_sh->count);
1176                         if (use_new_offset(conf, sh))
1177                                 rbi->bi_iter.bi_sector = (sh->sector
1178                                                   + rrdev->new_data_offset);
1179                         else
1180                                 rbi->bi_iter.bi_sector = (sh->sector
1181                                                   + rrdev->data_offset);
1182                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1183                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1184                         sh->dev[i].rvec.bv_page = sh->dev[i].page;
1185                         rbi->bi_vcnt = 1;
1186                         rbi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1187                         rbi->bi_io_vec[0].bv_offset = 0;
1188                         rbi->bi_iter.bi_size = STRIPE_SIZE;
1189                         rbi->bi_write_hint = sh->dev[i].write_hint;
1190                         sh->dev[i].write_hint = RWF_WRITE_LIFE_NOT_SET;
1191                         /*
1192                          * If this is discard request, set bi_vcnt 0. We don't
1193                          * want to confuse SCSI because SCSI will replace payload
1194                          */
1195                         if (op == REQ_OP_DISCARD)
1196                                 rbi->bi_vcnt = 0;
1197                         if (conf->mddev->gendisk)
1198                                 trace_block_bio_remap(rbi->bi_disk->queue,
1199                                                       rbi, disk_devt(conf->mddev->gendisk),
1200                                                       sh->dev[i].sector);
1201                         if (should_defer && op_is_write(op))
1202                                 bio_list_add(&pending_bios, rbi);
1203                         else
1204                                 generic_make_request(rbi);
1205                 }
1206                 if (!rdev && !rrdev) {
1207                         if (op_is_write(op))
1208                                 set_bit(STRIPE_DEGRADED, &sh->state);
1209                         pr_debug("skip op %d on disc %d for sector %llu\n",
1210                                 bi->bi_opf, i, (unsigned long long)sh->sector);
1211                         clear_bit(R5_LOCKED, &sh->dev[i].flags);
1212                         set_bit(STRIPE_HANDLE, &sh->state);
1213                 }
1214
1215                 if (!head_sh->batch_head)
1216                         continue;
1217                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1218                                       batch_list);
1219                 if (sh != head_sh)
1220                         goto again;
1221         }
1222
1223         if (should_defer && !bio_list_empty(&pending_bios))
1224                 defer_issue_bios(conf, head_sh->sector, &pending_bios);
1225 }
1226
1227 static struct dma_async_tx_descriptor *
1228 async_copy_data(int frombio, struct bio *bio, struct page **page,
1229         sector_t sector, struct dma_async_tx_descriptor *tx,
1230         struct stripe_head *sh, int no_skipcopy)
1231 {
1232         struct bio_vec bvl;
1233         struct bvec_iter iter;
1234         struct page *bio_page;
1235         int page_offset;
1236         struct async_submit_ctl submit;
1237         enum async_tx_flags flags = 0;
1238
1239         if (bio->bi_iter.bi_sector >= sector)
1240                 page_offset = (signed)(bio->bi_iter.bi_sector - sector) * 512;
1241         else
1242                 page_offset = (signed)(sector - bio->bi_iter.bi_sector) * -512;
1243
1244         if (frombio)
1245                 flags |= ASYNC_TX_FENCE;
1246         init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
1247
1248         bio_for_each_segment(bvl, bio, iter) {
1249                 int len = bvl.bv_len;
1250                 int clen;
1251                 int b_offset = 0;
1252
1253                 if (page_offset < 0) {
1254                         b_offset = -page_offset;
1255                         page_offset += b_offset;
1256                         len -= b_offset;
1257                 }
1258
1259                 if (len > 0 && page_offset + len > STRIPE_SIZE)
1260                         clen = STRIPE_SIZE - page_offset;
1261                 else
1262                         clen = len;
1263
1264                 if (clen > 0) {
1265                         b_offset += bvl.bv_offset;
1266                         bio_page = bvl.bv_page;
1267                         if (frombio) {
1268                                 if (sh->raid_conf->skip_copy &&
1269                                     b_offset == 0 && page_offset == 0 &&
1270                                     clen == STRIPE_SIZE &&
1271                                     !no_skipcopy)
1272                                         *page = bio_page;
1273                                 else
1274                                         tx = async_memcpy(*page, bio_page, page_offset,
1275                                                   b_offset, clen, &submit);
1276                         } else
1277                                 tx = async_memcpy(bio_page, *page, b_offset,
1278                                                   page_offset, clen, &submit);
1279                 }
1280                 /* chain the operations */
1281                 submit.depend_tx = tx;
1282
1283                 if (clen < len) /* hit end of page */
1284                         break;
1285                 page_offset +=  len;
1286         }
1287
1288         return tx;
1289 }
1290
1291 static void ops_complete_biofill(void *stripe_head_ref)
1292 {
1293         struct stripe_head *sh = stripe_head_ref;
1294         int i;
1295
1296         pr_debug("%s: stripe %llu\n", __func__,
1297                 (unsigned long long)sh->sector);
1298
1299         /* clear completed biofills */
1300         for (i = sh->disks; i--; ) {
1301                 struct r5dev *dev = &sh->dev[i];
1302
1303                 /* acknowledge completion of a biofill operation */
1304                 /* and check if we need to reply to a read request,
1305                  * new R5_Wantfill requests are held off until
1306                  * !STRIPE_BIOFILL_RUN
1307                  */
1308                 if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
1309                         struct bio *rbi, *rbi2;
1310
1311                         BUG_ON(!dev->read);
1312                         rbi = dev->read;
1313                         dev->read = NULL;
1314                         while (rbi && rbi->bi_iter.bi_sector <
1315                                 dev->sector + STRIPE_SECTORS) {
1316                                 rbi2 = r5_next_bio(rbi, dev->sector);
1317                                 bio_endio(rbi);
1318                                 rbi = rbi2;
1319                         }
1320                 }
1321         }
1322         clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
1323
1324         set_bit(STRIPE_HANDLE, &sh->state);
1325         raid5_release_stripe(sh);
1326 }
1327
1328 static void ops_run_biofill(struct stripe_head *sh)
1329 {
1330         struct dma_async_tx_descriptor *tx = NULL;
1331         struct async_submit_ctl submit;
1332         int i;
1333
1334         BUG_ON(sh->batch_head);
1335         pr_debug("%s: stripe %llu\n", __func__,
1336                 (unsigned long long)sh->sector);
1337
1338         for (i = sh->disks; i--; ) {
1339                 struct r5dev *dev = &sh->dev[i];
1340                 if (test_bit(R5_Wantfill, &dev->flags)) {
1341                         struct bio *rbi;
1342                         spin_lock_irq(&sh->stripe_lock);
1343                         dev->read = rbi = dev->toread;
1344                         dev->toread = NULL;
1345                         spin_unlock_irq(&sh->stripe_lock);
1346                         while (rbi && rbi->bi_iter.bi_sector <
1347                                 dev->sector + STRIPE_SECTORS) {
1348                                 tx = async_copy_data(0, rbi, &dev->page,
1349                                                      dev->sector, tx, sh, 0);
1350                                 rbi = r5_next_bio(rbi, dev->sector);
1351                         }
1352                 }
1353         }
1354
1355         atomic_inc(&sh->count);
1356         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
1357         async_trigger_callback(&submit);
1358 }
1359
1360 static void mark_target_uptodate(struct stripe_head *sh, int target)
1361 {
1362         struct r5dev *tgt;
1363
1364         if (target < 0)
1365                 return;
1366
1367         tgt = &sh->dev[target];
1368         set_bit(R5_UPTODATE, &tgt->flags);
1369         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1370         clear_bit(R5_Wantcompute, &tgt->flags);
1371 }
1372
1373 static void ops_complete_compute(void *stripe_head_ref)
1374 {
1375         struct stripe_head *sh = stripe_head_ref;
1376
1377         pr_debug("%s: stripe %llu\n", __func__,
1378                 (unsigned long long)sh->sector);
1379
1380         /* mark the computed target(s) as uptodate */
1381         mark_target_uptodate(sh, sh->ops.target);
1382         mark_target_uptodate(sh, sh->ops.target2);
1383
1384         clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
1385         if (sh->check_state == check_state_compute_run)
1386                 sh->check_state = check_state_compute_result;
1387         set_bit(STRIPE_HANDLE, &sh->state);
1388         raid5_release_stripe(sh);
1389 }
1390
1391 /* return a pointer to the address conversion region of the scribble buffer */
1392 static struct page **to_addr_page(struct raid5_percpu *percpu, int i)
1393 {
1394         return percpu->scribble + i * percpu->scribble_obj_size;
1395 }
1396
1397 /* return a pointer to the address conversion region of the scribble buffer */
1398 static addr_conv_t *to_addr_conv(struct stripe_head *sh,
1399                                  struct raid5_percpu *percpu, int i)
1400 {
1401         return (void *) (to_addr_page(percpu, i) + sh->disks + 2);
1402 }
1403
1404 static struct dma_async_tx_descriptor *
1405 ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
1406 {
1407         int disks = sh->disks;
1408         struct page **xor_srcs = to_addr_page(percpu, 0);
1409         int target = sh->ops.target;
1410         struct r5dev *tgt = &sh->dev[target];
1411         struct page *xor_dest = tgt->page;
1412         int count = 0;
1413         struct dma_async_tx_descriptor *tx;
1414         struct async_submit_ctl submit;
1415         int i;
1416
1417         BUG_ON(sh->batch_head);
1418
1419         pr_debug("%s: stripe %llu block: %d\n",
1420                 __func__, (unsigned long long)sh->sector, target);
1421         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1422
1423         for (i = disks; i--; )
1424                 if (i != target)
1425                         xor_srcs[count++] = sh->dev[i].page;
1426
1427         atomic_inc(&sh->count);
1428
1429         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
1430                           ops_complete_compute, sh, to_addr_conv(sh, percpu, 0));
1431         if (unlikely(count == 1))
1432                 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
1433         else
1434                 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1435
1436         return tx;
1437 }
1438
1439 /* set_syndrome_sources - populate source buffers for gen_syndrome
1440  * @srcs - (struct page *) array of size sh->disks
1441  * @sh - stripe_head to parse
1442  *
1443  * Populates srcs in proper layout order for the stripe and returns the
1444  * 'count' of sources to be used in a call to async_gen_syndrome.  The P
1445  * destination buffer is recorded in srcs[count] and the Q destination
1446  * is recorded in srcs[count+1]].
1447  */
1448 static int set_syndrome_sources(struct page **srcs,
1449                                 struct stripe_head *sh,
1450                                 int srctype)
1451 {
1452         int disks = sh->disks;
1453         int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
1454         int d0_idx = raid6_d0(sh);
1455         int count;
1456         int i;
1457
1458         for (i = 0; i < disks; i++)
1459                 srcs[i] = NULL;
1460
1461         count = 0;
1462         i = d0_idx;
1463         do {
1464                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1465                 struct r5dev *dev = &sh->dev[i];
1466
1467                 if (i == sh->qd_idx || i == sh->pd_idx ||
1468                     (srctype == SYNDROME_SRC_ALL) ||
1469                     (srctype == SYNDROME_SRC_WANT_DRAIN &&
1470                      (test_bit(R5_Wantdrain, &dev->flags) ||
1471                       test_bit(R5_InJournal, &dev->flags))) ||
1472                     (srctype == SYNDROME_SRC_WRITTEN &&
1473                      (dev->written ||
1474                       test_bit(R5_InJournal, &dev->flags)))) {
1475                         if (test_bit(R5_InJournal, &dev->flags))
1476                                 srcs[slot] = sh->dev[i].orig_page;
1477                         else
1478                                 srcs[slot] = sh->dev[i].page;
1479                 }
1480                 i = raid6_next_disk(i, disks);
1481         } while (i != d0_idx);
1482
1483         return syndrome_disks;
1484 }
1485
1486 static struct dma_async_tx_descriptor *
1487 ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
1488 {
1489         int disks = sh->disks;
1490         struct page **blocks = to_addr_page(percpu, 0);
1491         int target;
1492         int qd_idx = sh->qd_idx;
1493         struct dma_async_tx_descriptor *tx;
1494         struct async_submit_ctl submit;
1495         struct r5dev *tgt;
1496         struct page *dest;
1497         int i;
1498         int count;
1499
1500         BUG_ON(sh->batch_head);
1501         if (sh->ops.target < 0)
1502                 target = sh->ops.target2;
1503         else if (sh->ops.target2 < 0)
1504                 target = sh->ops.target;
1505         else
1506                 /* we should only have one valid target */
1507                 BUG();
1508         BUG_ON(target < 0);
1509         pr_debug("%s: stripe %llu block: %d\n",
1510                 __func__, (unsigned long long)sh->sector, target);
1511
1512         tgt = &sh->dev[target];
1513         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1514         dest = tgt->page;
1515
1516         atomic_inc(&sh->count);
1517
1518         if (target == qd_idx) {
1519                 count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1520                 blocks[count] = NULL; /* regenerating p is not necessary */
1521                 BUG_ON(blocks[count+1] != dest); /* q should already be set */
1522                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1523                                   ops_complete_compute, sh,
1524                                   to_addr_conv(sh, percpu, 0));
1525                 tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
1526         } else {
1527                 /* Compute any data- or p-drive using XOR */
1528                 count = 0;
1529                 for (i = disks; i-- ; ) {
1530                         if (i == target || i == qd_idx)
1531                                 continue;
1532                         blocks[count++] = sh->dev[i].page;
1533                 }
1534
1535                 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1536                                   NULL, ops_complete_compute, sh,
1537                                   to_addr_conv(sh, percpu, 0));
1538                 tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
1539         }
1540
1541         return tx;
1542 }
1543
1544 static struct dma_async_tx_descriptor *
1545 ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
1546 {
1547         int i, count, disks = sh->disks;
1548         int syndrome_disks = sh->ddf_layout ? disks : disks-2;
1549         int d0_idx = raid6_d0(sh);
1550         int faila = -1, failb = -1;
1551         int target = sh->ops.target;
1552         int target2 = sh->ops.target2;
1553         struct r5dev *tgt = &sh->dev[target];
1554         struct r5dev *tgt2 = &sh->dev[target2];
1555         struct dma_async_tx_descriptor *tx;
1556         struct page **blocks = to_addr_page(percpu, 0);
1557         struct async_submit_ctl submit;
1558
1559         BUG_ON(sh->batch_head);
1560         pr_debug("%s: stripe %llu block1: %d block2: %d\n",
1561                  __func__, (unsigned long long)sh->sector, target, target2);
1562         BUG_ON(target < 0 || target2 < 0);
1563         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1564         BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
1565
1566         /* we need to open-code set_syndrome_sources to handle the
1567          * slot number conversion for 'faila' and 'failb'
1568          */
1569         for (i = 0; i < disks ; i++)
1570                 blocks[i] = NULL;
1571         count = 0;
1572         i = d0_idx;
1573         do {
1574                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1575
1576                 blocks[slot] = sh->dev[i].page;
1577
1578                 if (i == target)
1579                         faila = slot;
1580                 if (i == target2)
1581                         failb = slot;
1582                 i = raid6_next_disk(i, disks);
1583         } while (i != d0_idx);
1584
1585         BUG_ON(faila == failb);
1586         if (failb < faila)
1587                 swap(faila, failb);
1588         pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
1589                  __func__, (unsigned long long)sh->sector, faila, failb);
1590
1591         atomic_inc(&sh->count);
1592
1593         if (failb == syndrome_disks+1) {
1594                 /* Q disk is one of the missing disks */
1595                 if (faila == syndrome_disks) {
1596                         /* Missing P+Q, just recompute */
1597                         init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1598                                           ops_complete_compute, sh,
1599                                           to_addr_conv(sh, percpu, 0));
1600                         return async_gen_syndrome(blocks, 0, syndrome_disks+2,
1601                                                   STRIPE_SIZE, &submit);
1602                 } else {
1603                         struct page *dest;
1604                         int data_target;
1605                         int qd_idx = sh->qd_idx;
1606
1607                         /* Missing D+Q: recompute D from P, then recompute Q */
1608                         if (target == qd_idx)
1609                                 data_target = target2;
1610                         else
1611                                 data_target = target;
1612
1613                         count = 0;
1614                         for (i = disks; i-- ; ) {
1615                                 if (i == data_target || i == qd_idx)
1616                                         continue;
1617                                 blocks[count++] = sh->dev[i].page;
1618                         }
1619                         dest = sh->dev[data_target].page;
1620                         init_async_submit(&submit,
1621                                           ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1622                                           NULL, NULL, NULL,
1623                                           to_addr_conv(sh, percpu, 0));
1624                         tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
1625                                        &submit);
1626
1627                         count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1628                         init_async_submit(&submit, ASYNC_TX_FENCE, tx,
1629                                           ops_complete_compute, sh,
1630                                           to_addr_conv(sh, percpu, 0));
1631                         return async_gen_syndrome(blocks, 0, count+2,
1632                                                   STRIPE_SIZE, &submit);
1633                 }
1634         } else {
1635                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1636                                   ops_complete_compute, sh,
1637                                   to_addr_conv(sh, percpu, 0));
1638                 if (failb == syndrome_disks) {
1639                         /* We're missing D+P. */
1640                         return async_raid6_datap_recov(syndrome_disks+2,
1641                                                        STRIPE_SIZE, faila,
1642                                                        blocks, &submit);
1643                 } else {
1644                         /* We're missing D+D. */
1645                         return async_raid6_2data_recov(syndrome_disks+2,
1646                                                        STRIPE_SIZE, faila, failb,
1647                                                        blocks, &submit);
1648                 }
1649         }
1650 }
1651
1652 static void ops_complete_prexor(void *stripe_head_ref)
1653 {
1654         struct stripe_head *sh = stripe_head_ref;
1655
1656         pr_debug("%s: stripe %llu\n", __func__,
1657                 (unsigned long long)sh->sector);
1658
1659         if (r5c_is_writeback(sh->raid_conf->log))
1660                 /*
1661                  * raid5-cache write back uses orig_page during prexor.
1662                  * After prexor, it is time to free orig_page
1663                  */
1664                 r5c_release_extra_page(sh);
1665 }
1666
1667 static struct dma_async_tx_descriptor *
1668 ops_run_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
1669                 struct dma_async_tx_descriptor *tx)
1670 {
1671         int disks = sh->disks;
1672         struct page **xor_srcs = to_addr_page(percpu, 0);
1673         int count = 0, pd_idx = sh->pd_idx, i;
1674         struct async_submit_ctl submit;
1675
1676         /* existing parity data subtracted */
1677         struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1678
1679         BUG_ON(sh->batch_head);
1680         pr_debug("%s: stripe %llu\n", __func__,
1681                 (unsigned long long)sh->sector);
1682
1683         for (i = disks; i--; ) {
1684                 struct r5dev *dev = &sh->dev[i];
1685                 /* Only process blocks that are known to be uptodate */
1686                 if (test_bit(R5_InJournal, &dev->flags))
1687                         xor_srcs[count++] = dev->orig_page;
1688                 else if (test_bit(R5_Wantdrain, &dev->flags))
1689                         xor_srcs[count++] = dev->page;
1690         }
1691
1692         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1693                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1694         tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1695
1696         return tx;
1697 }
1698
1699 static struct dma_async_tx_descriptor *
1700 ops_run_prexor6(struct stripe_head *sh, struct raid5_percpu *percpu,
1701                 struct dma_async_tx_descriptor *tx)
1702 {
1703         struct page **blocks = to_addr_page(percpu, 0);
1704         int count;
1705         struct async_submit_ctl submit;
1706
1707         pr_debug("%s: stripe %llu\n", __func__,
1708                 (unsigned long long)sh->sector);
1709
1710         count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_WANT_DRAIN);
1711
1712         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_PQ_XOR_DST, tx,
1713                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1714         tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
1715
1716         return tx;
1717 }
1718
1719 static struct dma_async_tx_descriptor *
1720 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1721 {
1722         struct r5conf *conf = sh->raid_conf;
1723         int disks = sh->disks;
1724         int i;
1725         struct stripe_head *head_sh = sh;
1726
1727         pr_debug("%s: stripe %llu\n", __func__,
1728                 (unsigned long long)sh->sector);
1729
1730         for (i = disks; i--; ) {
1731                 struct r5dev *dev;
1732                 struct bio *chosen;
1733
1734                 sh = head_sh;
1735                 if (test_and_clear_bit(R5_Wantdrain, &head_sh->dev[i].flags)) {
1736                         struct bio *wbi;
1737
1738 again:
1739                         dev = &sh->dev[i];
1740                         /*
1741                          * clear R5_InJournal, so when rewriting a page in
1742                          * journal, it is not skipped by r5l_log_stripe()
1743                          */
1744                         clear_bit(R5_InJournal, &dev->flags);
1745                         spin_lock_irq(&sh->stripe_lock);
1746                         chosen = dev->towrite;
1747                         dev->towrite = NULL;
1748                         sh->overwrite_disks = 0;
1749                         BUG_ON(dev->written);
1750                         wbi = dev->written = chosen;
1751                         spin_unlock_irq(&sh->stripe_lock);
1752                         WARN_ON(dev->page != dev->orig_page);
1753
1754                         while (wbi && wbi->bi_iter.bi_sector <
1755                                 dev->sector + STRIPE_SECTORS) {
1756                                 if (wbi->bi_opf & REQ_FUA)
1757                                         set_bit(R5_WantFUA, &dev->flags);
1758                                 if (wbi->bi_opf & REQ_SYNC)
1759                                         set_bit(R5_SyncIO, &dev->flags);
1760                                 if (bio_op(wbi) == REQ_OP_DISCARD)
1761                                         set_bit(R5_Discard, &dev->flags);
1762                                 else {
1763                                         tx = async_copy_data(1, wbi, &dev->page,
1764                                                              dev->sector, tx, sh,
1765                                                              r5c_is_writeback(conf->log));
1766                                         if (dev->page != dev->orig_page &&
1767                                             !r5c_is_writeback(conf->log)) {
1768                                                 set_bit(R5_SkipCopy, &dev->flags);
1769                                                 clear_bit(R5_UPTODATE, &dev->flags);
1770                                                 clear_bit(R5_OVERWRITE, &dev->flags);
1771                                         }
1772                                 }
1773                                 wbi = r5_next_bio(wbi, dev->sector);
1774                         }
1775
1776                         if (head_sh->batch_head) {
1777                                 sh = list_first_entry(&sh->batch_list,
1778                                                       struct stripe_head,
1779                                                       batch_list);
1780                                 if (sh == head_sh)
1781                                         continue;
1782                                 goto again;
1783                         }
1784                 }
1785         }
1786
1787         return tx;
1788 }
1789
1790 static void ops_complete_reconstruct(void *stripe_head_ref)
1791 {
1792         struct stripe_head *sh = stripe_head_ref;
1793         int disks = sh->disks;
1794         int pd_idx = sh->pd_idx;
1795         int qd_idx = sh->qd_idx;
1796         int i;
1797         bool fua = false, sync = false, discard = false;
1798
1799         pr_debug("%s: stripe %llu\n", __func__,
1800                 (unsigned long long)sh->sector);
1801
1802         for (i = disks; i--; ) {
1803                 fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
1804                 sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
1805                 discard |= test_bit(R5_Discard, &sh->dev[i].flags);
1806         }
1807
1808         for (i = disks; i--; ) {
1809                 struct r5dev *dev = &sh->dev[i];
1810
1811                 if (dev->written || i == pd_idx || i == qd_idx) {
1812                         if (!discard && !test_bit(R5_SkipCopy, &dev->flags)) {
1813                                 set_bit(R5_UPTODATE, &dev->flags);
1814                                 if (test_bit(STRIPE_EXPAND_READY, &sh->state))
1815                                         set_bit(R5_Expanded, &dev->flags);
1816                         }
1817                         if (fua)
1818                                 set_bit(R5_WantFUA, &dev->flags);
1819                         if (sync)
1820                                 set_bit(R5_SyncIO, &dev->flags);
1821                 }
1822         }
1823
1824         if (sh->reconstruct_state == reconstruct_state_drain_run)
1825                 sh->reconstruct_state = reconstruct_state_drain_result;
1826         else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
1827                 sh->reconstruct_state = reconstruct_state_prexor_drain_result;
1828         else {
1829                 BUG_ON(sh->reconstruct_state != reconstruct_state_run);
1830                 sh->reconstruct_state = reconstruct_state_result;
1831         }
1832
1833         set_bit(STRIPE_HANDLE, &sh->state);
1834         raid5_release_stripe(sh);
1835 }
1836
1837 static void
1838 ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
1839                      struct dma_async_tx_descriptor *tx)
1840 {
1841         int disks = sh->disks;
1842         struct page **xor_srcs;
1843         struct async_submit_ctl submit;
1844         int count, pd_idx = sh->pd_idx, i;
1845         struct page *xor_dest;
1846         int prexor = 0;
1847         unsigned long flags;
1848         int j = 0;
1849         struct stripe_head *head_sh = sh;
1850         int last_stripe;
1851
1852         pr_debug("%s: stripe %llu\n", __func__,
1853                 (unsigned long long)sh->sector);
1854
1855         for (i = 0; i < sh->disks; i++) {
1856                 if (pd_idx == i)
1857                         continue;
1858                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
1859                         break;
1860         }
1861         if (i >= sh->disks) {
1862                 atomic_inc(&sh->count);
1863                 set_bit(R5_Discard, &sh->dev[pd_idx].flags);
1864                 ops_complete_reconstruct(sh);
1865                 return;
1866         }
1867 again:
1868         count = 0;
1869         xor_srcs = to_addr_page(percpu, j);
1870         /* check if prexor is active which means only process blocks
1871          * that are part of a read-modify-write (written)
1872          */
1873         if (head_sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1874                 prexor = 1;
1875                 xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1876                 for (i = disks; i--; ) {
1877                         struct r5dev *dev = &sh->dev[i];
1878                         if (head_sh->dev[i].written ||
1879                             test_bit(R5_InJournal, &head_sh->dev[i].flags))
1880                                 xor_srcs[count++] = dev->page;
1881                 }
1882         } else {
1883                 xor_dest = sh->dev[pd_idx].page;
1884                 for (i = disks; i--; ) {
1885                         struct r5dev *dev = &sh->dev[i];
1886                         if (i != pd_idx)
1887                                 xor_srcs[count++] = dev->page;
1888                 }
1889         }
1890
1891         /* 1/ if we prexor'd then the dest is reused as a source
1892          * 2/ if we did not prexor then we are redoing the parity
1893          * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
1894          * for the synchronous xor case
1895          */
1896         last_stripe = !head_sh->batch_head ||
1897                 list_first_entry(&sh->batch_list,
1898                                  struct stripe_head, batch_list) == head_sh;
1899         if (last_stripe) {
1900                 flags = ASYNC_TX_ACK |
1901                         (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
1902
1903                 atomic_inc(&head_sh->count);
1904                 init_async_submit(&submit, flags, tx, ops_complete_reconstruct, head_sh,
1905                                   to_addr_conv(sh, percpu, j));
1906         } else {
1907                 flags = prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST;
1908                 init_async_submit(&submit, flags, tx, NULL, NULL,
1909                                   to_addr_conv(sh, percpu, j));
1910         }
1911
1912         if (unlikely(count == 1))
1913                 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
1914         else
1915                 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1916         if (!last_stripe) {
1917                 j++;
1918                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1919                                       batch_list);
1920                 goto again;
1921         }
1922 }
1923
1924 static void
1925 ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
1926                      struct dma_async_tx_descriptor *tx)
1927 {
1928         struct async_submit_ctl submit;
1929         struct page **blocks;
1930         int count, i, j = 0;
1931         struct stripe_head *head_sh = sh;
1932         int last_stripe;
1933         int synflags;
1934         unsigned long txflags;
1935
1936         pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
1937
1938         for (i = 0; i < sh->disks; i++) {
1939                 if (sh->pd_idx == i || sh->qd_idx == i)
1940                         continue;
1941                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
1942                         break;
1943         }
1944         if (i >= sh->disks) {
1945                 atomic_inc(&sh->count);
1946                 set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
1947                 set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
1948                 ops_complete_reconstruct(sh);
1949                 return;
1950         }
1951
1952 again:
1953         blocks = to_addr_page(percpu, j);
1954
1955         if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1956                 synflags = SYNDROME_SRC_WRITTEN;
1957                 txflags = ASYNC_TX_ACK | ASYNC_TX_PQ_XOR_DST;
1958         } else {
1959                 synflags = SYNDROME_SRC_ALL;
1960                 txflags = ASYNC_TX_ACK;
1961         }
1962
1963         count = set_syndrome_sources(blocks, sh, synflags);
1964         last_stripe = !head_sh->batch_head ||
1965                 list_first_entry(&sh->batch_list,
1966                                  struct stripe_head, batch_list) == head_sh;
1967
1968         if (last_stripe) {
1969                 atomic_inc(&head_sh->count);
1970                 init_async_submit(&submit, txflags, tx, ops_complete_reconstruct,
1971                                   head_sh, to_addr_conv(sh, percpu, j));
1972         } else
1973                 init_async_submit(&submit, 0, tx, NULL, NULL,
1974                                   to_addr_conv(sh, percpu, j));
1975         tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
1976         if (!last_stripe) {
1977                 j++;
1978                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1979                                       batch_list);
1980                 goto again;
1981         }
1982 }
1983
1984 static void ops_complete_check(void *stripe_head_ref)
1985 {
1986         struct stripe_head *sh = stripe_head_ref;
1987
1988         pr_debug("%s: stripe %llu\n", __func__,
1989                 (unsigned long long)sh->sector);
1990
1991         sh->check_state = check_state_check_result;
1992         set_bit(STRIPE_HANDLE, &sh->state);
1993         raid5_release_stripe(sh);
1994 }
1995
1996 static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
1997 {
1998         int disks = sh->disks;
1999         int pd_idx = sh->pd_idx;
2000         int qd_idx = sh->qd_idx;
2001         struct page *xor_dest;
2002         struct page **xor_srcs = to_addr_page(percpu, 0);
2003         struct dma_async_tx_descriptor *tx;
2004         struct async_submit_ctl submit;
2005         int count;
2006         int i;
2007
2008         pr_debug("%s: stripe %llu\n", __func__,
2009                 (unsigned long long)sh->sector);
2010
2011         BUG_ON(sh->batch_head);
2012         count = 0;
2013         xor_dest = sh->dev[pd_idx].page;
2014         xor_srcs[count++] = xor_dest;
2015         for (i = disks; i--; ) {
2016                 if (i == pd_idx || i == qd_idx)
2017                         continue;
2018                 xor_srcs[count++] = sh->dev[i].page;
2019         }
2020
2021         init_async_submit(&submit, 0, NULL, NULL, NULL,
2022                           to_addr_conv(sh, percpu, 0));
2023         tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
2024                            &sh->ops.zero_sum_result, &submit);
2025
2026         atomic_inc(&sh->count);
2027         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
2028         tx = async_trigger_callback(&submit);
2029 }
2030
2031 static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
2032 {
2033         struct page **srcs = to_addr_page(percpu, 0);
2034         struct async_submit_ctl submit;
2035         int count;
2036
2037         pr_debug("%s: stripe %llu checkp: %d\n", __func__,
2038                 (unsigned long long)sh->sector, checkp);
2039
2040         BUG_ON(sh->batch_head);
2041         count = set_syndrome_sources(srcs, sh, SYNDROME_SRC_ALL);
2042         if (!checkp)
2043                 srcs[count] = NULL;
2044
2045         atomic_inc(&sh->count);
2046         init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
2047                           sh, to_addr_conv(sh, percpu, 0));
2048         async_syndrome_val(srcs, 0, count+2, STRIPE_SIZE,
2049                            &sh->ops.zero_sum_result, percpu->spare_page, &submit);
2050 }
2051
2052 static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
2053 {
2054         int overlap_clear = 0, i, disks = sh->disks;
2055         struct dma_async_tx_descriptor *tx = NULL;
2056         struct r5conf *conf = sh->raid_conf;
2057         int level = conf->level;
2058         struct raid5_percpu *percpu;
2059         unsigned long cpu;
2060
2061         cpu = get_cpu();
2062         percpu = per_cpu_ptr(conf->percpu, cpu);
2063         if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
2064                 ops_run_biofill(sh);
2065                 overlap_clear++;
2066         }
2067
2068         if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
2069                 if (level < 6)
2070                         tx = ops_run_compute5(sh, percpu);
2071                 else {
2072                         if (sh->ops.target2 < 0 || sh->ops.target < 0)
2073                                 tx = ops_run_compute6_1(sh, percpu);
2074                         else
2075                                 tx = ops_run_compute6_2(sh, percpu);
2076                 }
2077                 /* terminate the chain if reconstruct is not set to be run */
2078                 if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
2079                         async_tx_ack(tx);
2080         }
2081
2082         if (test_bit(STRIPE_OP_PREXOR, &ops_request)) {
2083                 if (level < 6)
2084                         tx = ops_run_prexor5(sh, percpu, tx);
2085                 else
2086                         tx = ops_run_prexor6(sh, percpu, tx);
2087         }
2088
2089         if (test_bit(STRIPE_OP_PARTIAL_PARITY, &ops_request))
2090                 tx = ops_run_partial_parity(sh, percpu, tx);
2091
2092         if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
2093                 tx = ops_run_biodrain(sh, tx);
2094                 overlap_clear++;
2095         }
2096
2097         if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
2098                 if (level < 6)
2099                         ops_run_reconstruct5(sh, percpu, tx);
2100                 else
2101                         ops_run_reconstruct6(sh, percpu, tx);
2102         }
2103
2104         if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
2105                 if (sh->check_state == check_state_run)
2106                         ops_run_check_p(sh, percpu);
2107                 else if (sh->check_state == check_state_run_q)
2108                         ops_run_check_pq(sh, percpu, 0);
2109                 else if (sh->check_state == check_state_run_pq)
2110                         ops_run_check_pq(sh, percpu, 1);
2111                 else
2112                         BUG();
2113         }
2114
2115         if (overlap_clear && !sh->batch_head)
2116                 for (i = disks; i--; ) {
2117                         struct r5dev *dev = &sh->dev[i];
2118                         if (test_and_clear_bit(R5_Overlap, &dev->flags))
2119                                 wake_up(&sh->raid_conf->wait_for_overlap);
2120                 }
2121         put_cpu();
2122 }
2123
2124 static void free_stripe(struct kmem_cache *sc, struct stripe_head *sh)
2125 {
2126         if (sh->ppl_page)
2127                 __free_page(sh->ppl_page);
2128         kmem_cache_free(sc, sh);
2129 }
2130
2131 static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp,
2132         int disks, struct r5conf *conf)
2133 {
2134         struct stripe_head *sh;
2135         int i;
2136
2137         sh = kmem_cache_zalloc(sc, gfp);
2138         if (sh) {
2139                 spin_lock_init(&sh->stripe_lock);
2140                 spin_lock_init(&sh->batch_lock);
2141                 INIT_LIST_HEAD(&sh->batch_list);
2142                 INIT_LIST_HEAD(&sh->lru);
2143                 INIT_LIST_HEAD(&sh->r5c);
2144                 INIT_LIST_HEAD(&sh->log_list);
2145                 atomic_set(&sh->count, 1);
2146                 sh->raid_conf = conf;
2147                 sh->log_start = MaxSector;
2148                 for (i = 0; i < disks; i++) {
2149                         struct r5dev *dev = &sh->dev[i];
2150
2151                         bio_init(&dev->req, &dev->vec, 1);
2152                         bio_init(&dev->rreq, &dev->rvec, 1);
2153                 }
2154
2155                 if (raid5_has_ppl(conf)) {
2156                         sh->ppl_page = alloc_page(gfp);
2157                         if (!sh->ppl_page) {
2158                                 free_stripe(sc, sh);
2159                                 sh = NULL;
2160                         }
2161                 }
2162         }
2163         return sh;
2164 }
2165 static int grow_one_stripe(struct r5conf *conf, gfp_t gfp)
2166 {
2167         struct stripe_head *sh;
2168
2169         sh = alloc_stripe(conf->slab_cache, gfp, conf->pool_size, conf);
2170         if (!sh)
2171                 return 0;
2172
2173         if (grow_buffers(sh, gfp)) {
2174                 shrink_buffers(sh);
2175                 free_stripe(conf->slab_cache, sh);
2176                 return 0;
2177         }
2178         sh->hash_lock_index =
2179                 conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS;
2180         /* we just created an active stripe so... */
2181         atomic_inc(&conf->active_stripes);
2182
2183         raid5_release_stripe(sh);
2184         conf->max_nr_stripes++;
2185         return 1;
2186 }
2187
2188 static int grow_stripes(struct r5conf *conf, int num)
2189 {
2190         struct kmem_cache *sc;
2191         size_t namelen = sizeof(conf->cache_name[0]);
2192         int devs = max(conf->raid_disks, conf->previous_raid_disks);
2193
2194         if (conf->mddev->gendisk)
2195                 snprintf(conf->cache_name[0], namelen,
2196                         "raid%d-%s", conf->level, mdname(conf->mddev));
2197         else
2198                 snprintf(conf->cache_name[0], namelen,
2199                         "raid%d-%p", conf->level, conf->mddev);
2200         snprintf(conf->cache_name[1], namelen, "%.27s-alt", conf->cache_name[0]);
2201
2202         conf->active_name = 0;
2203         sc = kmem_cache_create(conf->cache_name[conf->active_name],
2204                                sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
2205                                0, 0, NULL);
2206         if (!sc)
2207                 return 1;
2208         conf->slab_cache = sc;
2209         conf->pool_size = devs;
2210         while (num--)
2211                 if (!grow_one_stripe(conf, GFP_KERNEL))
2212                         return 1;
2213
2214         return 0;
2215 }
2216
2217 /**
2218  * scribble_len - return the required size of the scribble region
2219  * @num - total number of disks in the array
2220  *
2221  * The size must be enough to contain:
2222  * 1/ a struct page pointer for each device in the array +2
2223  * 2/ room to convert each entry in (1) to its corresponding dma
2224  *    (dma_map_page()) or page (page_address()) address.
2225  *
2226  * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
2227  * calculate over all devices (not just the data blocks), using zeros in place
2228  * of the P and Q blocks.
2229  */
2230 static int scribble_alloc(struct raid5_percpu *percpu,
2231                           int num, int cnt, gfp_t flags)
2232 {
2233         size_t obj_size =
2234                 sizeof(struct page *) * (num+2) +
2235                 sizeof(addr_conv_t) * (num+2);
2236         void *scribble;
2237
2238         scribble = kvmalloc_array(cnt, obj_size, flags);
2239         if (!scribble)
2240                 return -ENOMEM;
2241
2242         kvfree(percpu->scribble);
2243
2244         percpu->scribble = scribble;
2245         percpu->scribble_obj_size = obj_size;
2246         return 0;
2247 }
2248
2249 static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
2250 {
2251         unsigned long cpu;
2252         int err = 0;
2253
2254         /*
2255          * Never shrink. And mddev_suspend() could deadlock if this is called
2256          * from raid5d. In that case, scribble_disks and scribble_sectors
2257          * should equal to new_disks and new_sectors
2258          */
2259         if (conf->scribble_disks >= new_disks &&
2260             conf->scribble_sectors >= new_sectors)
2261                 return 0;
2262         mddev_suspend(conf->mddev);
2263         get_online_cpus();
2264
2265         for_each_present_cpu(cpu) {
2266                 struct raid5_percpu *percpu;
2267
2268                 percpu = per_cpu_ptr(conf->percpu, cpu);
2269                 err = scribble_alloc(percpu, new_disks,
2270                                      new_sectors / STRIPE_SECTORS,
2271                                      GFP_NOIO);
2272                 if (err)
2273                         break;
2274         }
2275
2276         put_online_cpus();
2277         mddev_resume(conf->mddev);
2278         if (!err) {
2279                 conf->scribble_disks = new_disks;
2280                 conf->scribble_sectors = new_sectors;
2281         }
2282         return err;
2283 }
2284
2285 static int resize_stripes(struct r5conf *conf, int newsize)
2286 {
2287         /* Make all the stripes able to hold 'newsize' devices.
2288          * New slots in each stripe get 'page' set to a new page.
2289          *
2290          * This happens in stages:
2291          * 1/ create a new kmem_cache and allocate the required number of
2292          *    stripe_heads.
2293          * 2/ gather all the old stripe_heads and transfer the pages across
2294          *    to the new stripe_heads.  This will have the side effect of
2295          *    freezing the array as once all stripe_heads have been collected,
2296          *    no IO will be possible.  Old stripe heads are freed once their
2297          *    pages have been transferred over, and the old kmem_cache is
2298          *    freed when all stripes are done.
2299          * 3/ reallocate conf->disks to be suitable bigger.  If this fails,
2300          *    we simple return a failure status - no need to clean anything up.
2301          * 4/ allocate new pages for the new slots in the new stripe_heads.
2302          *    If this fails, we don't bother trying the shrink the
2303          *    stripe_heads down again, we just leave them as they are.
2304          *    As each stripe_head is processed the new one is released into
2305          *    active service.
2306          *
2307          * Once step2 is started, we cannot afford to wait for a write,
2308          * so we use GFP_NOIO allocations.
2309          */
2310         struct stripe_head *osh, *nsh;
2311         LIST_HEAD(newstripes);
2312         struct disk_info *ndisks;
2313         int err = 0;
2314         struct kmem_cache *sc;
2315         int i;
2316         int hash, cnt;
2317
2318         md_allow_write(conf->mddev);
2319
2320         /* Step 1 */
2321         sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
2322                                sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
2323                                0, 0, NULL);
2324         if (!sc)
2325                 return -ENOMEM;
2326
2327         /* Need to ensure auto-resizing doesn't interfere */
2328         mutex_lock(&conf->cache_size_mutex);
2329
2330         for (i = conf->max_nr_stripes; i; i--) {
2331                 nsh = alloc_stripe(sc, GFP_KERNEL, newsize, conf);
2332                 if (!nsh)
2333                         break;
2334
2335                 list_add(&nsh->lru, &newstripes);
2336         }
2337         if (i) {
2338                 /* didn't get enough, give up */
2339                 while (!list_empty(&newstripes)) {
2340                         nsh = list_entry(newstripes.next, struct stripe_head, lru);
2341                         list_del(&nsh->lru);
2342                         free_stripe(sc, nsh);
2343                 }
2344                 kmem_cache_destroy(sc);
2345                 mutex_unlock(&conf->cache_size_mutex);
2346                 return -ENOMEM;
2347         }
2348         /* Step 2 - Must use GFP_NOIO now.
2349          * OK, we have enough stripes, start collecting inactive
2350          * stripes and copying them over
2351          */
2352         hash = 0;
2353         cnt = 0;
2354         list_for_each_entry(nsh, &newstripes, lru) {
2355                 lock_device_hash_lock(conf, hash);
2356                 wait_event_cmd(conf->wait_for_stripe,
2357                                     !list_empty(conf->inactive_list + hash),
2358                                     unlock_device_hash_lock(conf, hash),
2359                                     lock_device_hash_lock(conf, hash));
2360                 osh = get_free_stripe(conf, hash);
2361                 unlock_device_hash_lock(conf, hash);
2362
2363                 for(i=0; i<conf->pool_size; i++) {
2364                         nsh->dev[i].page = osh->dev[i].page;
2365                         nsh->dev[i].orig_page = osh->dev[i].page;
2366                 }
2367                 nsh->hash_lock_index = hash;
2368                 free_stripe(conf->slab_cache, osh);
2369                 cnt++;
2370                 if (cnt >= conf->max_nr_stripes / NR_STRIPE_HASH_LOCKS +
2371                     !!((conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS) > hash)) {
2372                         hash++;
2373                         cnt = 0;
2374                 }
2375         }
2376         kmem_cache_destroy(conf->slab_cache);
2377
2378         /* Step 3.
2379          * At this point, we are holding all the stripes so the array
2380          * is completely stalled, so now is a good time to resize
2381          * conf->disks and the scribble region
2382          */
2383         ndisks = kcalloc(newsize, sizeof(struct disk_info), GFP_NOIO);
2384         if (ndisks) {
2385                 for (i = 0; i < conf->pool_size; i++)
2386                         ndisks[i] = conf->disks[i];
2387
2388                 for (i = conf->pool_size; i < newsize; i++) {
2389                         ndisks[i].extra_page = alloc_page(GFP_NOIO);
2390                         if (!ndisks[i].extra_page)
2391                                 err = -ENOMEM;
2392                 }
2393
2394                 if (err) {
2395                         for (i = conf->pool_size; i < newsize; i++)
2396                                 if (ndisks[i].extra_page)
2397                                         put_page(ndisks[i].extra_page);
2398                         kfree(ndisks);
2399                 } else {
2400                         kfree(conf->disks);
2401                         conf->disks = ndisks;
2402                 }
2403         } else
2404                 err = -ENOMEM;
2405
2406         mutex_unlock(&conf->cache_size_mutex);
2407
2408         conf->slab_cache = sc;
2409         conf->active_name = 1-conf->active_name;
2410
2411         /* Step 4, return new stripes to service */
2412         while(!list_empty(&newstripes)) {
2413                 nsh = list_entry(newstripes.next, struct stripe_head, lru);
2414                 list_del_init(&nsh->lru);
2415
2416                 for (i=conf->raid_disks; i < newsize; i++)
2417                         if (nsh->dev[i].page == NULL) {
2418                                 struct page *p = alloc_page(GFP_NOIO);
2419                                 nsh->dev[i].page = p;
2420                                 nsh->dev[i].orig_page = p;
2421                                 if (!p)
2422                                         err = -ENOMEM;
2423                         }
2424                 raid5_release_stripe(nsh);
2425         }
2426         /* critical section pass, GFP_NOIO no longer needed */
2427
2428         if (!err)
2429                 conf->pool_size = newsize;
2430         return err;
2431 }
2432
2433 static int drop_one_stripe(struct r5conf *conf)
2434 {
2435         struct stripe_head *sh;
2436         int hash = (conf->max_nr_stripes - 1) & STRIPE_HASH_LOCKS_MASK;
2437
2438         spin_lock_irq(conf->hash_locks + hash);
2439         sh = get_free_stripe(conf, hash);
2440         spin_unlock_irq(conf->hash_locks + hash);
2441         if (!sh)
2442                 return 0;
2443         BUG_ON(atomic_read(&sh->count));
2444         shrink_buffers(sh);
2445         free_stripe(conf->slab_cache, sh);
2446         atomic_dec(&conf->active_stripes);
2447         conf->max_nr_stripes--;
2448         return 1;
2449 }
2450
2451 static void shrink_stripes(struct r5conf *conf)
2452 {
2453         while (conf->max_nr_stripes &&
2454                drop_one_stripe(conf))
2455                 ;
2456
2457         kmem_cache_destroy(conf->slab_cache);
2458         conf->slab_cache = NULL;
2459 }
2460
2461 static void raid5_end_read_request(struct bio * bi)
2462 {
2463         struct stripe_head *sh = bi->bi_private;
2464         struct r5conf *conf = sh->raid_conf;
2465         int disks = sh->disks, i;
2466         char b[BDEVNAME_SIZE];
2467         struct md_rdev *rdev = NULL;
2468         sector_t s;
2469
2470         for (i=0 ; i<disks; i++)
2471                 if (bi == &sh->dev[i].req)
2472                         break;
2473
2474         pr_debug("end_read_request %llu/%d, count: %d, error %d.\n",
2475                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2476                 bi->bi_status);
2477         if (i == disks) {
2478                 bio_reset(bi);
2479                 BUG();
2480                 return;
2481         }
2482         if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2483                 /* If replacement finished while this request was outstanding,
2484                  * 'replacement' might be NULL already.
2485                  * In that case it moved down to 'rdev'.
2486                  * rdev is not removed until all requests are finished.
2487                  */
2488                 rdev = conf->disks[i].replacement;
2489         if (!rdev)
2490                 rdev = conf->disks[i].rdev;
2491
2492         if (use_new_offset(conf, sh))
2493                 s = sh->sector + rdev->new_data_offset;
2494         else
2495                 s = sh->sector + rdev->data_offset;
2496         if (!bi->bi_status) {
2497                 set_bit(R5_UPTODATE, &sh->dev[i].flags);
2498                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2499                         /* Note that this cannot happen on a
2500                          * replacement device.  We just fail those on
2501                          * any error
2502                          */
2503                         pr_info_ratelimited(
2504                                 "md/raid:%s: read error corrected (%lu sectors at %llu on %s)\n",
2505                                 mdname(conf->mddev), STRIPE_SECTORS,
2506                                 (unsigned long long)s,
2507                                 bdevname(rdev->bdev, b));
2508                         atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
2509                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2510                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2511                 } else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2512                         clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2513
2514                 if (test_bit(R5_InJournal, &sh->dev[i].flags))
2515                         /*
2516                          * end read for a page in journal, this
2517                          * must be preparing for prexor in rmw
2518                          */
2519                         set_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags);
2520
2521                 if (atomic_read(&rdev->read_errors))
2522                         atomic_set(&rdev->read_errors, 0);
2523         } else {
2524                 const char *bdn = bdevname(rdev->bdev, b);
2525                 int retry = 0;
2526                 int set_bad = 0;
2527
2528                 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
2529                 atomic_inc(&rdev->read_errors);
2530                 if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2531                         pr_warn_ratelimited(
2532                                 "md/raid:%s: read error on replacement device (sector %llu on %s).\n",
2533                                 mdname(conf->mddev),
2534                                 (unsigned long long)s,
2535                                 bdn);
2536                 else if (conf->mddev->degraded >= conf->max_degraded) {
2537                         set_bad = 1;
2538                         pr_warn_ratelimited(
2539                                 "md/raid:%s: read error not correctable (sector %llu on %s).\n",
2540                                 mdname(conf->mddev),
2541                                 (unsigned long long)s,
2542                                 bdn);
2543                 } else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
2544                         /* Oh, no!!! */
2545                         set_bad = 1;
2546                         pr_warn_ratelimited(
2547                                 "md/raid:%s: read error NOT corrected!! (sector %llu on %s).\n",
2548                                 mdname(conf->mddev),
2549                                 (unsigned long long)s,
2550                                 bdn);
2551                 } else if (atomic_read(&rdev->read_errors)
2552                          > conf->max_nr_stripes)
2553                         pr_warn("md/raid:%s: Too many read errors, failing device %s.\n",
2554                                mdname(conf->mddev), bdn);
2555                 else
2556                         retry = 1;
2557                 if (set_bad && test_bit(In_sync, &rdev->flags)
2558                     && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2559                         retry = 1;
2560                 if (retry)
2561                         if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
2562                                 set_bit(R5_ReadError, &sh->dev[i].flags);
2563                                 clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2564                         } else
2565                                 set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2566                 else {
2567                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2568                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2569                         if (!(set_bad
2570                               && test_bit(In_sync, &rdev->flags)
2571                               && rdev_set_badblocks(
2572                                       rdev, sh->sector, STRIPE_SECTORS, 0)))
2573                                 md_error(conf->mddev, rdev);
2574                 }
2575         }
2576         rdev_dec_pending(rdev, conf->mddev);
2577         bio_reset(bi);
2578         clear_bit(R5_LOCKED, &sh->dev[i].flags);
2579         set_bit(STRIPE_HANDLE, &sh->state);
2580         raid5_release_stripe(sh);
2581 }
2582
2583 static void raid5_end_write_request(struct bio *bi)
2584 {
2585         struct stripe_head *sh = bi->bi_private;
2586         struct r5conf *conf = sh->raid_conf;
2587         int disks = sh->disks, i;
2588         struct md_rdev *uninitialized_var(rdev);
2589         sector_t first_bad;
2590         int bad_sectors;
2591         int replacement = 0;
2592
2593         for (i = 0 ; i < disks; i++) {
2594                 if (bi == &sh->dev[i].req) {
2595                         rdev = conf->disks[i].rdev;
2596                         break;
2597                 }
2598                 if (bi == &sh->dev[i].rreq) {
2599                         rdev = conf->disks[i].replacement;
2600                         if (rdev)
2601                                 replacement = 1;
2602                         else
2603                                 /* rdev was removed and 'replacement'
2604                                  * replaced it.  rdev is not removed
2605                                  * until all requests are finished.
2606                                  */
2607                                 rdev = conf->disks[i].rdev;
2608                         break;
2609                 }
2610         }
2611         pr_debug("end_write_request %llu/%d, count %d, error: %d.\n",
2612                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2613                 bi->bi_status);
2614         if (i == disks) {
2615                 bio_reset(bi);
2616                 BUG();
2617                 return;
2618         }
2619
2620         if (replacement) {
2621                 if (bi->bi_status)
2622                         md_error(conf->mddev, rdev);
2623                 else if (is_badblock(rdev, sh->sector,
2624                                      STRIPE_SECTORS,
2625                                      &first_bad, &bad_sectors))
2626                         set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
2627         } else {
2628                 if (bi->bi_status) {
2629                         set_bit(STRIPE_DEGRADED, &sh->state);
2630                         set_bit(WriteErrorSeen, &rdev->flags);
2631                         set_bit(R5_WriteError, &sh->dev[i].flags);
2632                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
2633                                 set_bit(MD_RECOVERY_NEEDED,
2634                                         &rdev->mddev->recovery);
2635                 } else if (is_badblock(rdev, sh->sector,
2636                                        STRIPE_SECTORS,
2637                                        &first_bad, &bad_sectors)) {
2638                         set_bit(R5_MadeGood, &sh->dev[i].flags);
2639                         if (test_bit(R5_ReadError, &sh->dev[i].flags))
2640                                 /* That was a successful write so make
2641                                  * sure it looks like we already did
2642                                  * a re-write.
2643                                  */
2644                                 set_bit(R5_ReWrite, &sh->dev[i].flags);
2645                 }
2646         }
2647         rdev_dec_pending(rdev, conf->mddev);
2648
2649         if (sh->batch_head && bi->bi_status && !replacement)
2650                 set_bit(STRIPE_BATCH_ERR, &sh->batch_head->state);
2651
2652         bio_reset(bi);
2653         if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
2654                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
2655         set_bit(STRIPE_HANDLE, &sh->state);
2656         raid5_release_stripe(sh);
2657
2658         if (sh->batch_head && sh != sh->batch_head)
2659                 raid5_release_stripe(sh->batch_head);
2660 }
2661
2662 static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
2663 {
2664         char b[BDEVNAME_SIZE];
2665         struct r5conf *conf = mddev->private;
2666         unsigned long flags;
2667         pr_debug("raid456: error called\n");
2668
2669         spin_lock_irqsave(&conf->device_lock, flags);
2670
2671         if (test_bit(In_sync, &rdev->flags) &&
2672             mddev->degraded == conf->max_degraded) {
2673                 /*
2674                  * Don't allow to achieve failed state
2675                  * Don't try to recover this device
2676                  */
2677                 conf->recovery_disabled = mddev->recovery_disabled;
2678                 spin_unlock_irqrestore(&conf->device_lock, flags);
2679                 return;
2680         }
2681
2682         set_bit(Faulty, &rdev->flags);
2683         clear_bit(In_sync, &rdev->flags);
2684         mddev->degraded = raid5_calc_degraded(conf);
2685         spin_unlock_irqrestore(&conf->device_lock, flags);
2686         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2687
2688         set_bit(Blocked, &rdev->flags);
2689         set_mask_bits(&mddev->sb_flags, 0,
2690                       BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
2691         pr_crit("md/raid:%s: Disk failure on %s, disabling device.\n"
2692                 "md/raid:%s: Operation continuing on %d devices.\n",
2693                 mdname(mddev),
2694                 bdevname(rdev->bdev, b),
2695                 mdname(mddev),
2696                 conf->raid_disks - mddev->degraded);
2697         r5c_update_on_rdev_error(mddev, rdev);
2698 }
2699
2700 /*
2701  * Input: a 'big' sector number,
2702  * Output: index of the data and parity disk, and the sector # in them.
2703  */
2704 sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
2705                               int previous, int *dd_idx,
2706                               struct stripe_head *sh)
2707 {
2708         sector_t stripe, stripe2;
2709         sector_t chunk_number;
2710         unsigned int chunk_offset;
2711         int pd_idx, qd_idx;
2712         int ddf_layout = 0;
2713         sector_t new_sector;
2714         int algorithm = previous ? conf->prev_algo
2715                                  : conf->algorithm;
2716         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2717                                          : conf->chunk_sectors;
2718         int raid_disks = previous ? conf->previous_raid_disks
2719                                   : conf->raid_disks;
2720         int data_disks = raid_disks - conf->max_degraded;
2721
2722         /* First compute the information on this sector */
2723
2724         /*
2725          * Compute the chunk number and the sector offset inside the chunk
2726          */
2727         chunk_offset = sector_div(r_sector, sectors_per_chunk);
2728         chunk_number = r_sector;
2729
2730         /*
2731          * Compute the stripe number
2732          */
2733         stripe = chunk_number;
2734         *dd_idx = sector_div(stripe, data_disks);
2735         stripe2 = stripe;
2736         /*
2737          * Select the parity disk based on the user selected algorithm.
2738          */
2739         pd_idx = qd_idx = -1;
2740         switch(conf->level) {
2741         case 4:
2742                 pd_idx = data_disks;
2743                 break;
2744         case 5:
2745                 switch (algorithm) {
2746                 case ALGORITHM_LEFT_ASYMMETRIC:
2747                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
2748                         if (*dd_idx >= pd_idx)
2749                                 (*dd_idx)++;
2750                         break;
2751                 case ALGORITHM_RIGHT_ASYMMETRIC:
2752                         pd_idx = sector_div(stripe2, raid_disks);
2753                         if (*dd_idx >= pd_idx)
2754                                 (*dd_idx)++;
2755                         break;
2756                 case ALGORITHM_LEFT_SYMMETRIC:
2757                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
2758                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2759                         break;
2760                 case ALGORITHM_RIGHT_SYMMETRIC:
2761                         pd_idx = sector_div(stripe2, raid_disks);
2762                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2763                         break;
2764                 case ALGORITHM_PARITY_0:
2765                         pd_idx = 0;
2766                         (*dd_idx)++;
2767                         break;
2768                 case ALGORITHM_PARITY_N:
2769                         pd_idx = data_disks;
2770                         break;
2771                 default:
2772                         BUG();
2773                 }
2774                 break;
2775         case 6:
2776
2777                 switch (algorithm) {
2778                 case ALGORITHM_LEFT_ASYMMETRIC:
2779                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2780                         qd_idx = pd_idx + 1;
2781                         if (pd_idx == raid_disks-1) {
2782                                 (*dd_idx)++;    /* Q D D D P */
2783                                 qd_idx = 0;
2784                         } else if (*dd_idx >= pd_idx)
2785                                 (*dd_idx) += 2; /* D D P Q D */
2786                         break;
2787                 case ALGORITHM_RIGHT_ASYMMETRIC:
2788                         pd_idx = sector_div(stripe2, raid_disks);
2789                         qd_idx = pd_idx + 1;
2790                         if (pd_idx == raid_disks-1) {
2791                                 (*dd_idx)++;    /* Q D D D P */
2792                                 qd_idx = 0;
2793                         } else if (*dd_idx >= pd_idx)
2794                                 (*dd_idx) += 2; /* D D P Q D */
2795                         break;
2796                 case ALGORITHM_LEFT_SYMMETRIC:
2797                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2798                         qd_idx = (pd_idx + 1) % raid_disks;
2799                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2800                         break;
2801                 case ALGORITHM_RIGHT_SYMMETRIC:
2802                         pd_idx = sector_div(stripe2, raid_disks);
2803                         qd_idx = (pd_idx + 1) % raid_disks;
2804                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2805                         break;
2806
2807                 case ALGORITHM_PARITY_0:
2808                         pd_idx = 0;
2809                         qd_idx = 1;
2810                         (*dd_idx) += 2;
2811                         break;
2812                 case ALGORITHM_PARITY_N:
2813                         pd_idx = data_disks;
2814                         qd_idx = data_disks + 1;
2815                         break;
2816
2817                 case ALGORITHM_ROTATING_ZERO_RESTART:
2818                         /* Exactly the same as RIGHT_ASYMMETRIC, but or
2819                          * of blocks for computing Q is different.
2820                          */
2821                         pd_idx = sector_div(stripe2, raid_disks);
2822                         qd_idx = pd_idx + 1;
2823                         if (pd_idx == raid_disks-1) {
2824                                 (*dd_idx)++;    /* Q D D D P */
2825                                 qd_idx = 0;
2826                         } else if (*dd_idx >= pd_idx)
2827                                 (*dd_idx) += 2; /* D D P Q D */
2828                         ddf_layout = 1;
2829                         break;
2830
2831                 case ALGORITHM_ROTATING_N_RESTART:
2832                         /* Same a left_asymmetric, by first stripe is
2833                          * D D D P Q  rather than
2834                          * Q D D D P
2835                          */
2836                         stripe2 += 1;
2837                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2838                         qd_idx = pd_idx + 1;
2839                         if (pd_idx == raid_disks-1) {
2840                                 (*dd_idx)++;    /* Q D D D P */
2841                                 qd_idx = 0;
2842                         } else if (*dd_idx >= pd_idx)
2843                                 (*dd_idx) += 2; /* D D P Q D */
2844                         ddf_layout = 1;
2845                         break;
2846
2847                 case ALGORITHM_ROTATING_N_CONTINUE:
2848                         /* Same as left_symmetric but Q is before P */
2849                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2850                         qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
2851                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2852                         ddf_layout = 1;
2853                         break;
2854
2855                 case ALGORITHM_LEFT_ASYMMETRIC_6:
2856                         /* RAID5 left_asymmetric, with Q on last device */
2857                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2858                         if (*dd_idx >= pd_idx)
2859                                 (*dd_idx)++;
2860                         qd_idx = raid_disks - 1;
2861                         break;
2862
2863                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
2864                         pd_idx = sector_div(stripe2, raid_disks-1);
2865                         if (*dd_idx >= pd_idx)
2866                                 (*dd_idx)++;
2867                         qd_idx = raid_disks - 1;
2868                         break;
2869
2870                 case ALGORITHM_LEFT_SYMMETRIC_6:
2871                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2872                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2873                         qd_idx = raid_disks - 1;
2874                         break;
2875
2876                 case ALGORITHM_RIGHT_SYMMETRIC_6:
2877                         pd_idx = sector_div(stripe2, raid_disks-1);
2878                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2879                         qd_idx = raid_disks - 1;
2880                         break;
2881
2882                 case ALGORITHM_PARITY_0_6:
2883                         pd_idx = 0;
2884                         (*dd_idx)++;
2885                         qd_idx = raid_disks - 1;
2886                         break;
2887
2888                 default:
2889                         BUG();
2890                 }
2891                 break;
2892         }
2893
2894         if (sh) {
2895                 sh->pd_idx = pd_idx;
2896                 sh->qd_idx = qd_idx;
2897                 sh->ddf_layout = ddf_layout;
2898         }
2899         /*
2900          * Finally, compute the new sector number
2901          */
2902         new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
2903         return new_sector;
2904 }
2905
2906 sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous)
2907 {
2908         struct r5conf *conf = sh->raid_conf;
2909         int raid_disks = sh->disks;
2910         int data_disks = raid_disks - conf->max_degraded;
2911         sector_t new_sector = sh->sector, check;
2912         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2913                                          : conf->chunk_sectors;
2914         int algorithm = previous ? conf->prev_algo
2915                                  : conf->algorithm;
2916         sector_t stripe;
2917         int chunk_offset;
2918         sector_t chunk_number;
2919         int dummy1, dd_idx = i;
2920         sector_t r_sector;
2921         struct stripe_head sh2;
2922
2923         chunk_offset = sector_div(new_sector, sectors_per_chunk);
2924         stripe = new_sector;
2925
2926         if (i == sh->pd_idx)
2927                 return 0;
2928         switch(conf->level) {
2929         case 4: break;
2930         case 5:
2931                 switch (algorithm) {
2932                 case ALGORITHM_LEFT_ASYMMETRIC:
2933                 case ALGORITHM_RIGHT_ASYMMETRIC:
2934                         if (i > sh->pd_idx)
2935                                 i--;
2936                         break;
2937                 case ALGORITHM_LEFT_SYMMETRIC:
2938                 case ALGORITHM_RIGHT_SYMMETRIC:
2939                         if (i < sh->pd_idx)
2940                                 i += raid_disks;
2941                         i -= (sh->pd_idx + 1);
2942                         break;
2943                 case ALGORITHM_PARITY_0:
2944                         i -= 1;
2945                         break;
2946                 case ALGORITHM_PARITY_N:
2947                         break;
2948                 default:
2949                         BUG();
2950                 }
2951                 break;
2952         case 6:
2953                 if (i == sh->qd_idx)
2954                         return 0; /* It is the Q disk */
2955                 switch (algorithm) {
2956                 case ALGORITHM_LEFT_ASYMMETRIC:
2957                 case ALGORITHM_RIGHT_ASYMMETRIC:
2958                 case ALGORITHM_ROTATING_ZERO_RESTART:
2959                 case ALGORITHM_ROTATING_N_RESTART:
2960                         if (sh->pd_idx == raid_disks-1)
2961                                 i--;    /* Q D D D P */
2962                         else if (i > sh->pd_idx)
2963                                 i -= 2; /* D D P Q D */
2964                         break;
2965                 case ALGORITHM_LEFT_SYMMETRIC:
2966                 case ALGORITHM_RIGHT_SYMMETRIC:
2967                         if (sh->pd_idx == raid_disks-1)
2968                                 i--; /* Q D D D P */
2969                         else {
2970                                 /* D D P Q D */
2971                                 if (i < sh->pd_idx)
2972                                         i += raid_disks;
2973                                 i -= (sh->pd_idx + 2);
2974                         }
2975                         break;
2976                 case ALGORITHM_PARITY_0:
2977                         i -= 2;
2978                         break;
2979                 case ALGORITHM_PARITY_N:
2980                         break;
2981                 case ALGORITHM_ROTATING_N_CONTINUE:
2982                         /* Like left_symmetric, but P is before Q */
2983                         if (sh->pd_idx == 0)
2984                                 i--;    /* P D D D Q */
2985                         else {
2986                                 /* D D Q P D */
2987                                 if (i < sh->pd_idx)
2988                                         i += raid_disks;
2989                                 i -= (sh->pd_idx + 1);
2990                         }
2991                         break;
2992                 case ALGORITHM_LEFT_ASYMMETRIC_6:
2993                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
2994                         if (i > sh->pd_idx)
2995                                 i--;
2996                         break;
2997                 case ALGORITHM_LEFT_SYMMETRIC_6:
2998                 case ALGORITHM_RIGHT_SYMMETRIC_6:
2999                         if (i < sh->pd_idx)
3000                                 i += data_disks + 1;
3001                         i -= (sh->pd_idx + 1);
3002                         break;
3003                 case ALGORITHM_PARITY_0_6:
3004                         i -= 1;
3005                         break;
3006                 default:
3007                         BUG();
3008                 }
3009                 break;
3010         }
3011
3012         chunk_number = stripe * data_disks + i;
3013         r_sector = chunk_number * sectors_per_chunk + chunk_offset;
3014
3015         check = raid5_compute_sector(conf, r_sector,
3016                                      previous, &dummy1, &sh2);
3017         if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
3018                 || sh2.qd_idx != sh->qd_idx) {
3019                 pr_warn("md/raid:%s: compute_blocknr: map not correct\n",
3020                         mdname(conf->mddev));
3021                 return 0;
3022         }
3023         return r_sector;
3024 }
3025
3026 /*
3027  * There are cases where we want handle_stripe_dirtying() and
3028  * schedule_reconstruction() to delay towrite to some dev of a stripe.
3029  *
3030  * This function checks whether we want to delay the towrite. Specifically,
3031  * we delay the towrite when:
3032  *
3033  *   1. degraded stripe has a non-overwrite to the missing dev, AND this
3034  *      stripe has data in journal (for other devices).
3035  *
3036  *      In this case, when reading data for the non-overwrite dev, it is
3037  *      necessary to handle complex rmw of write back cache (prexor with
3038  *      orig_page, and xor with page). To keep read path simple, we would
3039  *      like to flush data in journal to RAID disks first, so complex rmw
3040  *      is handled in the write patch (handle_stripe_dirtying).
3041  *
3042  *   2. when journal space is critical (R5C_LOG_CRITICAL=1)
3043  *
3044  *      It is important to be able to flush all stripes in raid5-cache.
3045  *      Therefore, we need reserve some space on the journal device for
3046  *      these flushes. If flush operation includes pending writes to the
3047  *      stripe, we need to reserve (conf->raid_disk + 1) pages per stripe
3048  *      for the flush out. If we exclude these pending writes from flush
3049  *      operation, we only need (conf->max_degraded + 1) pages per stripe.
3050  *      Therefore, excluding pending writes in these cases enables more
3051  *      efficient use of the journal device.
3052  *
3053  *      Note: To make sure the stripe makes progress, we only delay
3054  *      towrite for stripes with data already in journal (injournal > 0).
3055  *      When LOG_CRITICAL, stripes with injournal == 0 will be sent to
3056  *      no_space_stripes list.
3057  *
3058  *   3. during journal failure
3059  *      In journal failure, we try to flush all cached data to raid disks
3060  *      based on data in stripe cache. The array is read-only to upper
3061  *      layers, so we would skip all pending writes.
3062  *
3063  */
3064 static inline bool delay_towrite(struct r5conf *conf,
3065                                  struct r5dev *dev,
3066                                  struct stripe_head_state *s)
3067 {
3068         /* case 1 above */
3069         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3070             !test_bit(R5_Insync, &dev->flags) && s->injournal)
3071                 return true;
3072         /* case 2 above */
3073         if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
3074             s->injournal > 0)
3075                 return true;
3076         /* case 3 above */
3077         if (s->log_failed && s->injournal)
3078                 return true;
3079         return false;
3080 }
3081
3082 static void
3083 schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
3084                          int rcw, int expand)
3085 {
3086         int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx, disks = sh->disks;
3087         struct r5conf *conf = sh->raid_conf;
3088         int level = conf->level;
3089
3090         if (rcw) {
3091                 /*
3092                  * In some cases, handle_stripe_dirtying initially decided to
3093                  * run rmw and allocates extra page for prexor. However, rcw is
3094                  * cheaper later on. We need to free the extra page now,
3095                  * because we won't be able to do that in ops_complete_prexor().
3096                  */
3097                 r5c_release_extra_page(sh);
3098
3099                 for (i = disks; i--; ) {
3100                         struct r5dev *dev = &sh->dev[i];
3101
3102                         if (dev->towrite && !delay_towrite(conf, dev, s)) {
3103                                 set_bit(R5_LOCKED, &dev->flags);
3104                                 set_bit(R5_Wantdrain, &dev->flags);
3105                                 if (!expand)
3106                                         clear_bit(R5_UPTODATE, &dev->flags);
3107                                 s->locked++;
3108                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3109                                 set_bit(R5_LOCKED, &dev->flags);
3110                                 s->locked++;
3111                         }
3112                 }
3113                 /* if we are not expanding this is a proper write request, and
3114                  * there will be bios with new data to be drained into the
3115                  * stripe cache
3116                  */
3117                 if (!expand) {
3118                         if (!s->locked)
3119                                 /* False alarm, nothing to do */
3120                                 return;
3121                         sh->reconstruct_state = reconstruct_state_drain_run;
3122                         set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3123                 } else
3124                         sh->reconstruct_state = reconstruct_state_run;
3125
3126                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3127
3128                 if (s->locked + conf->max_degraded == disks)
3129                         if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
3130                                 atomic_inc(&conf->pending_full_writes);
3131         } else {
3132                 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
3133                         test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
3134                 BUG_ON(level == 6 &&
3135                         (!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
3136                            test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));
3137
3138                 for (i = disks; i--; ) {
3139                         struct r5dev *dev = &sh->dev[i];
3140                         if (i == pd_idx || i == qd_idx)
3141                                 continue;
3142
3143                         if (dev->towrite &&
3144                             (test_bit(R5_UPTODATE, &dev->flags) ||
3145                              test_bit(R5_Wantcompute, &dev->flags))) {
3146                                 set_bit(R5_Wantdrain, &dev->flags);
3147                                 set_bit(R5_LOCKED, &dev->flags);
3148                                 clear_bit(R5_UPTODATE, &dev->flags);
3149                                 s->locked++;
3150                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3151                                 set_bit(R5_LOCKED, &dev->flags);
3152                                 s->locked++;
3153                         }
3154                 }
3155                 if (!s->locked)
3156                         /* False alarm - nothing to do */
3157                         return;
3158                 sh->reconstruct_state = reconstruct_state_prexor_drain_run;
3159                 set_bit(STRIPE_OP_PREXOR, &s->ops_request);
3160                 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3161                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3162         }
3163
3164         /* keep the parity disk(s) locked while asynchronous operations
3165          * are in flight
3166          */
3167         set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
3168         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
3169         s->locked++;
3170
3171         if (level == 6) {
3172                 int qd_idx = sh->qd_idx;
3173                 struct r5dev *dev = &sh->dev[qd_idx];
3174
3175                 set_bit(R5_LOCKED, &dev->flags);
3176                 clear_bit(R5_UPTODATE, &dev->flags);
3177                 s->locked++;
3178         }
3179
3180         if (raid5_has_ppl(sh->raid_conf) && sh->ppl_page &&
3181             test_bit(STRIPE_OP_BIODRAIN, &s->ops_request) &&
3182             !test_bit(STRIPE_FULL_WRITE, &sh->state) &&
3183             test_bit(R5_Insync, &sh->dev[pd_idx].flags))
3184                 set_bit(STRIPE_OP_PARTIAL_PARITY, &s->ops_request);
3185
3186         pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
3187                 __func__, (unsigned long long)sh->sector,
3188                 s->locked, s->ops_request);
3189 }
3190
3191 /*
3192  * Each stripe/dev can have one or more bion attached.
3193  * toread/towrite point to the first in a chain.
3194  * The bi_next chain must be in order.
3195  */
3196 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx,
3197                           int forwrite, int previous)
3198 {
3199         struct bio **bip;
3200         struct r5conf *conf = sh->raid_conf;
3201         int firstwrite=0;
3202
3203         pr_debug("adding bi b#%llu to stripe s#%llu\n",
3204                 (unsigned long long)bi->bi_iter.bi_sector,
3205                 (unsigned long long)sh->sector);
3206
3207         spin_lock_irq(&sh->stripe_lock);
3208         sh->dev[dd_idx].write_hint = bi->bi_write_hint;
3209         /* Don't allow new IO added to stripes in batch list */
3210         if (sh->batch_head)
3211                 goto overlap;
3212         if (forwrite) {
3213                 bip = &sh->dev[dd_idx].towrite;
3214                 if (*bip == NULL)
3215                         firstwrite = 1;
3216         } else
3217                 bip = &sh->dev[dd_idx].toread;
3218         while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector) {
3219                 if (bio_end_sector(*bip) > bi->bi_iter.bi_sector)
3220                         goto overlap;
3221                 bip = & (*bip)->bi_next;
3222         }
3223         if (*bip && (*bip)->bi_iter.bi_sector < bio_end_sector(bi))
3224                 goto overlap;
3225
3226         if (forwrite && raid5_has_ppl(conf)) {
3227                 /*
3228                  * With PPL only writes to consecutive data chunks within a
3229                  * stripe are allowed because for a single stripe_head we can
3230                  * only have one PPL entry at a time, which describes one data
3231                  * range. Not really an overlap, but wait_for_overlap can be
3232                  * used to handle this.
3233                  */
3234                 sector_t sector;
3235                 sector_t first = 0;
3236                 sector_t last = 0;
3237                 int count = 0;
3238                 int i;
3239
3240                 for (i = 0; i < sh->disks; i++) {
3241                         if (i != sh->pd_idx &&
3242                             (i == dd_idx || sh->dev[i].towrite)) {
3243                                 sector = sh->dev[i].sector;
3244                                 if (count == 0 || sector < first)
3245                                         first = sector;
3246                                 if (sector > last)
3247                                         last = sector;
3248                                 count++;
3249                         }
3250                 }
3251
3252                 if (first + conf->chunk_sectors * (count - 1) != last)
3253                         goto overlap;
3254         }
3255
3256         if (!forwrite || previous)
3257                 clear_bit(STRIPE_BATCH_READY, &sh->state);
3258
3259         BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
3260         if (*bip)
3261                 bi->bi_next = *bip;
3262         *bip = bi;
3263         bio_inc_remaining(bi);
3264         md_write_inc(conf->mddev, bi);
3265
3266         if (forwrite) {
3267                 /* check if page is covered */
3268                 sector_t sector = sh->dev[dd_idx].sector;
3269                 for (bi=sh->dev[dd_idx].towrite;
3270                      sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
3271                              bi && bi->bi_iter.bi_sector <= sector;
3272                      bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
3273                         if (bio_end_sector(bi) >= sector)
3274                                 sector = bio_end_sector(bi);
3275                 }
3276                 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
3277                         if (!test_and_set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags))
3278                                 sh->overwrite_disks++;
3279         }
3280
3281         pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
3282                 (unsigned long long)(*bip)->bi_iter.bi_sector,
3283                 (unsigned long long)sh->sector, dd_idx);
3284
3285         if (conf->mddev->bitmap && firstwrite) {
3286                 /* Cannot hold spinlock over bitmap_startwrite,
3287                  * but must ensure this isn't added to a batch until
3288                  * we have added to the bitmap and set bm_seq.
3289                  * So set STRIPE_BITMAP_PENDING to prevent
3290                  * batching.
3291                  * If multiple add_stripe_bio() calls race here they
3292                  * much all set STRIPE_BITMAP_PENDING.  So only the first one
3293                  * to complete "bitmap_startwrite" gets to set
3294                  * STRIPE_BIT_DELAY.  This is important as once a stripe
3295                  * is added to a batch, STRIPE_BIT_DELAY cannot be changed
3296                  * any more.
3297                  */
3298                 set_bit(STRIPE_BITMAP_PENDING, &sh->state);
3299                 spin_unlock_irq(&sh->stripe_lock);
3300                 md_bitmap_startwrite(conf->mddev->bitmap, sh->sector,
3301                                      STRIPE_SECTORS, 0);
3302                 spin_lock_irq(&sh->stripe_lock);
3303                 clear_bit(STRIPE_BITMAP_PENDING, &sh->state);
3304                 if (!sh->batch_head) {
3305                         sh->bm_seq = conf->seq_flush+1;
3306                         set_bit(STRIPE_BIT_DELAY, &sh->state);
3307                 }
3308         }
3309         spin_unlock_irq(&sh->stripe_lock);
3310
3311         if (stripe_can_batch(sh))
3312                 stripe_add_to_batch_list(conf, sh);
3313         return 1;
3314
3315  overlap:
3316         set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
3317         spin_unlock_irq(&sh->stripe_lock);
3318         return 0;
3319 }
3320
3321 static void end_reshape(struct r5conf *conf);
3322
3323 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
3324                             struct stripe_head *sh)
3325 {
3326         int sectors_per_chunk =
3327                 previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
3328         int dd_idx;
3329         int chunk_offset = sector_div(stripe, sectors_per_chunk);
3330         int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
3331
3332         raid5_compute_sector(conf,
3333                              stripe * (disks - conf->max_degraded)
3334                              *sectors_per_chunk + chunk_offset,
3335                              previous,
3336                              &dd_idx, sh);
3337 }
3338
3339 static void
3340 handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
3341                      struct stripe_head_state *s, int disks)
3342 {
3343         int i;
3344         BUG_ON(sh->batch_head);
3345         for (i = disks; i--; ) {
3346                 struct bio *bi;
3347                 int bitmap_end = 0;
3348
3349                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
3350                         struct md_rdev *rdev;
3351                         rcu_read_lock();
3352                         rdev = rcu_dereference(conf->disks[i].rdev);
3353                         if (rdev && test_bit(In_sync, &rdev->flags) &&
3354                             !test_bit(Faulty, &rdev->flags))
3355                                 atomic_inc(&rdev->nr_pending);
3356                         else
3357                                 rdev = NULL;
3358                         rcu_read_unlock();
3359                         if (rdev) {
3360                                 if (!rdev_set_badblocks(
3361                                             rdev,
3362                                             sh->sector,
3363                                             STRIPE_SECTORS, 0))
3364                                         md_error(conf->mddev, rdev);
3365                                 rdev_dec_pending(rdev, conf->mddev);
3366                         }
3367                 }
3368                 spin_lock_irq(&sh->stripe_lock);
3369                 /* fail all writes first */
3370                 bi = sh->dev[i].towrite;
3371                 sh->dev[i].towrite = NULL;
3372                 sh->overwrite_disks = 0;
3373                 spin_unlock_irq(&sh->stripe_lock);
3374                 if (bi)
3375                         bitmap_end = 1;
3376
3377                 log_stripe_write_finished(sh);
3378
3379                 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3380                         wake_up(&conf->wait_for_overlap);
3381
3382                 while (bi && bi->bi_iter.bi_sector <
3383                         sh->dev[i].sector + STRIPE_SECTORS) {
3384                         struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
3385
3386                         md_write_end(conf->mddev);
3387                         bio_io_error(bi);
3388                         bi = nextbi;
3389                 }
3390                 if (bitmap_end)
3391                         md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3392                                            STRIPE_SECTORS, 0, 0);
3393                 bitmap_end = 0;
3394                 /* and fail all 'written' */
3395                 bi = sh->dev[i].written;
3396                 sh->dev[i].written = NULL;
3397                 if (test_and_clear_bit(R5_SkipCopy, &sh->dev[i].flags)) {
3398                         WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
3399                         sh->dev[i].page = sh->dev[i].orig_page;
3400                 }
3401
3402                 if (bi) bitmap_end = 1;
3403                 while (bi && bi->bi_iter.bi_sector <
3404                        sh->dev[i].sector + STRIPE_SECTORS) {
3405                         struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
3406
3407                         md_write_end(conf->mddev);
3408                         bio_io_error(bi);
3409                         bi = bi2;
3410                 }
3411
3412                 /* fail any reads if this device is non-operational and
3413                  * the data has not reached the cache yet.
3414                  */
3415                 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
3416                     s->failed > conf->max_degraded &&
3417                     (!test_bit(R5_Insync, &sh->dev[i].flags) ||
3418                       test_bit(R5_ReadError, &sh->dev[i].flags))) {
3419                         spin_lock_irq(&sh->stripe_lock);
3420                         bi = sh->dev[i].toread;
3421                         sh->dev[i].toread = NULL;
3422                         spin_unlock_irq(&sh->stripe_lock);
3423                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3424                                 wake_up(&conf->wait_for_overlap);
3425                         if (bi)
3426                                 s->to_read--;
3427                         while (bi && bi->bi_iter.bi_sector <
3428                                sh->dev[i].sector + STRIPE_SECTORS) {
3429                                 struct bio *nextbi =
3430                                         r5_next_bio(bi, sh->dev[i].sector);
3431
3432                                 bio_io_error(bi);
3433                                 bi = nextbi;
3434                         }
3435                 }
3436                 if (bitmap_end)
3437                         md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3438                                            STRIPE_SECTORS, 0, 0);
3439                 /* If we were in the middle of a write the parity block might
3440                  * still be locked - so just clear all R5_LOCKED flags
3441                  */
3442                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
3443         }
3444         s->to_write = 0;
3445         s->written = 0;
3446
3447         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3448                 if (atomic_dec_and_test(&conf->pending_full_writes))
3449                         md_wakeup_thread(conf->mddev->thread);
3450 }
3451
3452 static void
3453 handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
3454                    struct stripe_head_state *s)
3455 {
3456         int abort = 0;
3457         int i;
3458
3459         BUG_ON(sh->batch_head);
3460         clear_bit(STRIPE_SYNCING, &sh->state);
3461         if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
3462                 wake_up(&conf->wait_for_overlap);
3463         s->syncing = 0;
3464         s->replacing = 0;
3465         /* There is nothing more to do for sync/check/repair.
3466          * Don't even need to abort as that is handled elsewhere
3467          * if needed, and not always wanted e.g. if there is a known
3468          * bad block here.
3469          * For recover/replace we need to record a bad block on all
3470          * non-sync devices, or abort the recovery
3471          */
3472         if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
3473                 /* During recovery devices cannot be removed, so
3474                  * locking and refcounting of rdevs is not needed
3475                  */
3476                 rcu_read_lock();
3477                 for (i = 0; i < conf->raid_disks; i++) {
3478                         struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
3479                         if (rdev
3480                             && !test_bit(Faulty, &rdev->flags)
3481                             && !test_bit(In_sync, &rdev->flags)
3482                             && !rdev_set_badblocks(rdev, sh->sector,
3483                                                    STRIPE_SECTORS, 0))
3484                                 abort = 1;
3485                         rdev = rcu_dereference(conf->disks[i].replacement);
3486                         if (rdev
3487                             && !test_bit(Faulty, &rdev->flags)
3488                             && !test_bit(In_sync, &rdev->flags)
3489                             && !rdev_set_badblocks(rdev, sh->sector,
3490                                                    STRIPE_SECTORS, 0))
3491                                 abort = 1;
3492                 }
3493                 rcu_read_unlock();
3494                 if (abort)
3495                         conf->recovery_disabled =
3496                                 conf->mddev->recovery_disabled;
3497         }
3498         md_done_sync(conf->mddev, STRIPE_SECTORS, !abort);
3499 }
3500
3501 static int want_replace(struct stripe_head *sh, int disk_idx)
3502 {
3503         struct md_rdev *rdev;
3504         int rv = 0;
3505
3506         rcu_read_lock();
3507         rdev = rcu_dereference(sh->raid_conf->disks[disk_idx].replacement);
3508         if (rdev
3509             && !test_bit(Faulty, &rdev->flags)
3510             && !test_bit(In_sync, &rdev->flags)
3511             && (rdev->recovery_offset <= sh->sector
3512                 || rdev->mddev->recovery_cp <= sh->sector))
3513                 rv = 1;
3514         rcu_read_unlock();
3515         return rv;
3516 }
3517
3518 static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
3519                            int disk_idx, int disks)
3520 {
3521         struct r5dev *dev = &sh->dev[disk_idx];
3522         struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
3523                                   &sh->dev[s->failed_num[1]] };
3524         int i;
3525
3526
3527         if (test_bit(R5_LOCKED, &dev->flags) ||
3528             test_bit(R5_UPTODATE, &dev->flags))
3529                 /* No point reading this as we already have it or have
3530                  * decided to get it.
3531                  */
3532                 return 0;
3533
3534         if (dev->toread ||
3535             (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)))
3536                 /* We need this block to directly satisfy a request */
3537                 return 1;
3538
3539         if (s->syncing || s->expanding ||
3540             (s->replacing && want_replace(sh, disk_idx)))
3541                 /* When syncing, or expanding we read everything.
3542                  * When replacing, we need the replaced block.
3543                  */
3544                 return 1;
3545
3546         if ((s->failed >= 1 && fdev[0]->toread) ||
3547             (s->failed >= 2 && fdev[1]->toread))
3548                 /* If we want to read from a failed device, then
3549                  * we need to actually read every other device.
3550                  */
3551                 return 1;
3552
3553         /* Sometimes neither read-modify-write nor reconstruct-write
3554          * cycles can work.  In those cases we read every block we
3555          * can.  Then the parity-update is certain to have enough to
3556          * work with.
3557          * This can only be a problem when we need to write something,
3558          * and some device has failed.  If either of those tests
3559          * fail we need look no further.
3560          */
3561         if (!s->failed || !s->to_write)
3562                 return 0;
3563
3564         if (test_bit(R5_Insync, &dev->flags) &&
3565             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3566                 /* Pre-reads at not permitted until after short delay
3567                  * to gather multiple requests.  However if this
3568                  * device is no Insync, the block could only be computed
3569                  * and there is no need to delay that.
3570                  */
3571                 return 0;
3572
3573         for (i = 0; i < s->failed && i < 2; i++) {
3574                 if (fdev[i]->towrite &&
3575                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3576                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3577                         /* If we have a partial write to a failed
3578                          * device, then we will need to reconstruct
3579                          * the content of that device, so all other
3580                          * devices must be read.
3581                          */
3582                         return 1;
3583         }
3584
3585         /* If we are forced to do a reconstruct-write, either because
3586          * the current RAID6 implementation only supports that, or
3587          * because parity cannot be trusted and we are currently
3588          * recovering it, there is extra need to be careful.
3589          * If one of the devices that we would need to read, because
3590          * it is not being overwritten (and maybe not written at all)
3591          * is missing/faulty, then we need to read everything we can.
3592          */
3593         if (sh->raid_conf->level != 6 &&
3594             sh->sector < sh->raid_conf->mddev->recovery_cp)
3595                 /* reconstruct-write isn't being forced */
3596                 return 0;
3597         for (i = 0; i < s->failed && i < 2; i++) {
3598                 if (s->failed_num[i] != sh->pd_idx &&
3599                     s->failed_num[i] != sh->qd_idx &&
3600                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3601                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3602                         return 1;
3603         }
3604
3605         return 0;
3606 }
3607
3608 /* fetch_block - checks the given member device to see if its data needs
3609  * to be read or computed to satisfy a request.
3610  *
3611  * Returns 1 when no more member devices need to be checked, otherwise returns
3612  * 0 to tell the loop in handle_stripe_fill to continue
3613  */
3614 static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
3615                        int disk_idx, int disks)
3616 {
3617         struct r5dev *dev = &sh->dev[disk_idx];
3618
3619         /* is the data in this block needed, and can we get it? */
3620         if (need_this_block(sh, s, disk_idx, disks)) {
3621                 /* we would like to get this block, possibly by computing it,
3622                  * otherwise read it if the backing disk is insync
3623                  */
3624                 BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
3625                 BUG_ON(test_bit(R5_Wantread, &dev->flags));
3626                 BUG_ON(sh->batch_head);
3627
3628                 /*
3629                  * In the raid6 case if the only non-uptodate disk is P
3630                  * then we already trusted P to compute the other failed
3631                  * drives. It is safe to compute rather than re-read P.
3632                  * In other cases we only compute blocks from failed
3633                  * devices, otherwise check/repair might fail to detect
3634                  * a real inconsistency.
3635                  */
3636
3637                 if ((s->uptodate == disks - 1) &&
3638                     ((sh->qd_idx >= 0 && sh->pd_idx == disk_idx) ||
3639                     (s->failed && (disk_idx == s->failed_num[0] ||
3640                                    disk_idx == s->failed_num[1])))) {
3641                         /* have disk failed, and we're requested to fetch it;
3642                          * do compute it
3643                          */
3644                         pr_debug("Computing stripe %llu block %d\n",
3645                                (unsigned long long)sh->sector, disk_idx);
3646                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3647                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3648                         set_bit(R5_Wantcompute, &dev->flags);
3649                         sh->ops.target = disk_idx;
3650                         sh->ops.target2 = -1; /* no 2nd target */
3651                         s->req_compute = 1;
3652                         /* Careful: from this point on 'uptodate' is in the eye
3653                          * of raid_run_ops which services 'compute' operations
3654                          * before writes. R5_Wantcompute flags a block that will
3655                          * be R5_UPTODATE by the time it is needed for a
3656                          * subsequent operation.
3657                          */
3658                         s->uptodate++;
3659                         return 1;
3660                 } else if (s->uptodate == disks-2 && s->failed >= 2) {
3661                         /* Computing 2-failure is *very* expensive; only
3662                          * do it if failed >= 2
3663                          */
3664                         int other;
3665                         for (other = disks; other--; ) {
3666                                 if (other == disk_idx)
3667                                         continue;
3668                                 if (!test_bit(R5_UPTODATE,
3669                                       &sh->dev[other].flags))
3670                                         break;
3671                         }
3672                         BUG_ON(other < 0);
3673                         pr_debug("Computing stripe %llu blocks %d,%d\n",
3674                                (unsigned long long)sh->sector,
3675                                disk_idx, other);
3676                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3677                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3678                         set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
3679                         set_bit(R5_Wantcompute, &sh->dev[other].flags);
3680                         sh->ops.target = disk_idx;
3681                         sh->ops.target2 = other;
3682                         s->uptodate += 2;
3683                         s->req_compute = 1;
3684                         return 1;
3685                 } else if (test_bit(R5_Insync, &dev->flags)) {
3686                         set_bit(R5_LOCKED, &dev->flags);
3687                         set_bit(R5_Wantread, &dev->flags);
3688                         s->locked++;
3689                         pr_debug("Reading block %d (sync=%d)\n",
3690                                 disk_idx, s->syncing);
3691                 }
3692         }
3693
3694         return 0;
3695 }
3696
3697 /**
3698  * handle_stripe_fill - read or compute data to satisfy pending requests.
3699  */
3700 static void handle_stripe_fill(struct stripe_head *sh,
3701                                struct stripe_head_state *s,
3702                                int disks)
3703 {
3704         int i;
3705
3706         /* look for blocks to read/compute, skip this if a compute
3707          * is already in flight, or if the stripe contents are in the
3708          * midst of changing due to a write
3709          */
3710         if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
3711             !sh->reconstruct_state) {
3712
3713                 /*
3714                  * For degraded stripe with data in journal, do not handle
3715                  * read requests yet, instead, flush the stripe to raid
3716                  * disks first, this avoids handling complex rmw of write
3717                  * back cache (prexor with orig_page, and then xor with
3718                  * page) in the read path
3719                  */
3720                 if (s->injournal && s->failed) {
3721                         if (test_bit(STRIPE_R5C_CACHING, &sh->state))
3722                                 r5c_make_stripe_write_out(sh);
3723                         goto out;
3724                 }
3725
3726                 for (i = disks; i--; )
3727                         if (fetch_block(sh, s, i, disks))
3728                                 break;
3729         }
3730 out:
3731         set_bit(STRIPE_HANDLE, &sh->state);
3732 }
3733
3734 static void break_stripe_batch_list(struct stripe_head *head_sh,
3735                                     unsigned long handle_flags);
3736 /* handle_stripe_clean_event
3737  * any written block on an uptodate or failed drive can be returned.
3738  * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
3739  * never LOCKED, so we don't need to test 'failed' directly.
3740  */
3741 static void handle_stripe_clean_event(struct r5conf *conf,
3742         struct stripe_head *sh, int disks)
3743 {
3744         int i;
3745         struct r5dev *dev;
3746         int discard_pending = 0;
3747         struct stripe_head *head_sh = sh;
3748         bool do_endio = false;
3749
3750         for (i = disks; i--; )
3751                 if (sh->dev[i].written) {
3752                         dev = &sh->dev[i];
3753                         if (!test_bit(R5_LOCKED, &dev->flags) &&
3754                             (test_bit(R5_UPTODATE, &dev->flags) ||
3755                              test_bit(R5_Discard, &dev->flags) ||
3756                              test_bit(R5_SkipCopy, &dev->flags))) {
3757                                 /* We can return any write requests */
3758                                 struct bio *wbi, *wbi2;
3759                                 pr_debug("Return write for disc %d\n", i);
3760                                 if (test_and_clear_bit(R5_Discard, &dev->flags))
3761                                         clear_bit(R5_UPTODATE, &dev->flags);
3762                                 if (test_and_clear_bit(R5_SkipCopy, &dev->flags)) {
3763                                         WARN_ON(test_bit(R5_UPTODATE, &dev->flags));
3764                                 }
3765                                 do_endio = true;
3766
3767 returnbi:
3768                                 dev->page = dev->orig_page;
3769                                 wbi = dev->written;
3770                                 dev->written = NULL;
3771                                 while (wbi && wbi->bi_iter.bi_sector <
3772                                         dev->sector + STRIPE_SECTORS) {
3773                                         wbi2 = r5_next_bio(wbi, dev->sector);
3774                                         md_write_end(conf->mddev);
3775                                         bio_endio(wbi);
3776                                         wbi = wbi2;
3777                                 }
3778                                 md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3779                                                    STRIPE_SECTORS,
3780                                                    !test_bit(STRIPE_DEGRADED, &sh->state),
3781                                                    0);
3782                                 if (head_sh->batch_head) {
3783                                         sh = list_first_entry(&sh->batch_list,
3784                                                               struct stripe_head,
3785                                                               batch_list);
3786                                         if (sh != head_sh) {
3787                                                 dev = &sh->dev[i];
3788                                                 goto returnbi;
3789                                         }
3790                                 }
3791                                 sh = head_sh;
3792                                 dev = &sh->dev[i];
3793                         } else if (test_bit(R5_Discard, &dev->flags))
3794                                 discard_pending = 1;
3795                 }
3796
3797         log_stripe_write_finished(sh);
3798
3799         if (!discard_pending &&
3800             test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) {
3801                 int hash;
3802                 clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
3803                 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
3804                 if (sh->qd_idx >= 0) {
3805                         clear_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
3806                         clear_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags);
3807                 }
3808                 /* now that discard is done we can proceed with any sync */
3809                 clear_bit(STRIPE_DISCARD, &sh->state);
3810                 /*
3811                  * SCSI discard will change some bio fields and the stripe has
3812                  * no updated data, so remove it from hash list and the stripe
3813                  * will be reinitialized
3814                  */
3815 unhash:
3816                 hash = sh->hash_lock_index;
3817                 spin_lock_irq(conf->hash_locks + hash);
3818                 remove_hash(sh);
3819                 spin_unlock_irq(conf->hash_locks + hash);
3820                 if (head_sh->batch_head) {
3821                         sh = list_first_entry(&sh->batch_list,
3822                                               struct stripe_head, batch_list);
3823                         if (sh != head_sh)
3824                                         goto unhash;
3825                 }
3826                 sh = head_sh;
3827
3828                 if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
3829                         set_bit(STRIPE_HANDLE, &sh->state);
3830
3831         }
3832
3833         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3834                 if (atomic_dec_and_test(&conf->pending_full_writes))
3835                         md_wakeup_thread(conf->mddev->thread);
3836
3837         if (head_sh->batch_head && do_endio)
3838                 break_stripe_batch_list(head_sh, STRIPE_EXPAND_SYNC_FLAGS);
3839 }
3840
3841 /*
3842  * For RMW in write back cache, we need extra page in prexor to store the
3843  * old data. This page is stored in dev->orig_page.
3844  *
3845  * This function checks whether we have data for prexor. The exact logic
3846  * is:
3847  *       R5_UPTODATE && (!R5_InJournal || R5_OrigPageUPTDODATE)
3848  */
3849 static inline bool uptodate_for_rmw(struct r5dev *dev)
3850 {
3851         return (test_bit(R5_UPTODATE, &dev->flags)) &&
3852                 (!test_bit(R5_InJournal, &dev->flags) ||
3853                  test_bit(R5_OrigPageUPTDODATE, &dev->flags));
3854 }
3855
3856 static int handle_stripe_dirtying(struct r5conf *conf,
3857                                   struct stripe_head *sh,
3858                                   struct stripe_head_state *s,
3859                                   int disks)
3860 {
3861         int rmw = 0, rcw = 0, i;
3862         sector_t recovery_cp = conf->mddev->recovery_cp;
3863
3864         /* Check whether resync is now happening or should start.
3865          * If yes, then the array is dirty (after unclean shutdown or
3866          * initial creation), so parity in some stripes might be inconsistent.
3867          * In this case, we need to always do reconstruct-write, to ensure
3868          * that in case of drive failure or read-error correction, we
3869          * generate correct data from the parity.
3870          */
3871         if (conf->rmw_level == PARITY_DISABLE_RMW ||
3872             (recovery_cp < MaxSector && sh->sector >= recovery_cp &&
3873              s->failed == 0)) {
3874                 /* Calculate the real rcw later - for now make it
3875                  * look like rcw is cheaper
3876                  */
3877                 rcw = 1; rmw = 2;
3878                 pr_debug("force RCW rmw_level=%u, recovery_cp=%llu sh->sector=%llu\n",
3879                          conf->rmw_level, (unsigned long long)recovery_cp,
3880                          (unsigned long long)sh->sector);
3881         } else for (i = disks; i--; ) {
3882                 /* would I have to read this buffer for read_modify_write */
3883                 struct r5dev *dev = &sh->dev[i];
3884                 if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3885                      i == sh->pd_idx || i == sh->qd_idx ||
3886                      test_bit(R5_InJournal, &dev->flags)) &&
3887                     !test_bit(R5_LOCKED, &dev->flags) &&
3888                     !(uptodate_for_rmw(dev) ||
3889                       test_bit(R5_Wantcompute, &dev->flags))) {
3890                         if (test_bit(R5_Insync, &dev->flags))
3891                                 rmw++;
3892                         else
3893                                 rmw += 2*disks;  /* cannot read it */
3894                 }
3895                 /* Would I have to read this buffer for reconstruct_write */
3896                 if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3897                     i != sh->pd_idx && i != sh->qd_idx &&
3898                     !test_bit(R5_LOCKED, &dev->flags) &&
3899                     !(test_bit(R5_UPTODATE, &dev->flags) ||
3900                       test_bit(R5_Wantcompute, &dev->flags))) {
3901                         if (test_bit(R5_Insync, &dev->flags))
3902                                 rcw++;
3903                         else
3904                                 rcw += 2*disks;
3905                 }
3906         }
3907
3908         pr_debug("for sector %llu state 0x%lx, rmw=%d rcw=%d\n",
3909                  (unsigned long long)sh->sector, sh->state, rmw, rcw);
3910         set_bit(STRIPE_HANDLE, &sh->state);
3911         if ((rmw < rcw || (rmw == rcw && conf->rmw_level == PARITY_PREFER_RMW)) && rmw > 0) {
3912                 /* prefer read-modify-write, but need to get some data */
3913                 if (conf->mddev->queue)
3914                         blk_add_trace_msg(conf->mddev->queue,
3915                                           "raid5 rmw %llu %d",
3916                                           (unsigned long long)sh->sector, rmw);
3917                 for (i = disks; i--; ) {
3918                         struct r5dev *dev = &sh->dev[i];
3919                         if (test_bit(R5_InJournal, &dev->flags) &&
3920                             dev->page == dev->orig_page &&
3921                             !test_bit(R5_LOCKED, &sh->dev[sh->pd_idx].flags)) {
3922                                 /* alloc page for prexor */
3923                                 struct page *p = alloc_page(GFP_NOIO);
3924
3925                                 if (p) {
3926                                         dev->orig_page = p;
3927                                         continue;
3928                                 }
3929
3930                                 /*
3931                                  * alloc_page() failed, try use
3932                                  * disk_info->extra_page
3933                                  */
3934                                 if (!test_and_set_bit(R5C_EXTRA_PAGE_IN_USE,
3935                                                       &conf->cache_state)) {
3936                                         r5c_use_extra_page(sh);
3937                                         break;
3938                                 }
3939
3940                                 /* extra_page in use, add to delayed_list */
3941                                 set_bit(STRIPE_DELAYED, &sh->state);
3942                                 s->waiting_extra_page = 1;
3943                                 return -EAGAIN;
3944                         }
3945                 }
3946
3947                 for (i = disks; i--; ) {
3948                         struct r5dev *dev = &sh->dev[i];
3949                         if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3950                              i == sh->pd_idx || i == sh->qd_idx ||
3951                              test_bit(R5_InJournal, &dev->flags)) &&
3952                             !test_bit(R5_LOCKED, &dev->flags) &&
3953                             !(uptodate_for_rmw(dev) ||
3954                               test_bit(R5_Wantcompute, &dev->flags)) &&
3955                             test_bit(R5_Insync, &dev->flags)) {
3956                                 if (test_bit(STRIPE_PREREAD_ACTIVE,
3957                                              &sh->state)) {
3958                                         pr_debug("Read_old block %d for r-m-w\n",
3959                                                  i);
3960                                         set_bit(R5_LOCKED, &dev->flags);
3961                                         set_bit(R5_Wantread, &dev->flags);
3962                                         s->locked++;
3963                                 } else {
3964                                         set_bit(STRIPE_DELAYED, &sh->state);
3965                                         set_bit(STRIPE_HANDLE, &sh->state);
3966                                 }
3967                         }
3968                 }
3969         }
3970         if ((rcw < rmw || (rcw == rmw && conf->rmw_level != PARITY_PREFER_RMW)) && rcw > 0) {
3971                 /* want reconstruct write, but need to get some data */
3972                 int qread =0;
3973                 rcw = 0;
3974                 for (i = disks; i--; ) {
3975                         struct r5dev *dev = &sh->dev[i];
3976                         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3977                             i != sh->pd_idx && i != sh->qd_idx &&
3978                             !test_bit(R5_LOCKED, &dev->flags) &&
3979                             !(test_bit(R5_UPTODATE, &dev->flags) ||
3980                               test_bit(R5_Wantcompute, &dev->flags))) {
3981                                 rcw++;
3982                                 if (test_bit(R5_Insync, &dev->flags) &&
3983                                     test_bit(STRIPE_PREREAD_ACTIVE,
3984                                              &sh->state)) {
3985                                         pr_debug("Read_old block "
3986                                                 "%d for Reconstruct\n", i);
3987                                         set_bit(R5_LOCKED, &dev->flags);
3988                                         set_bit(R5_Wantread, &dev->flags);
3989                                         s->locked++;
3990                                         qread++;
3991                                 } else {
3992                                         set_bit(STRIPE_DELAYED, &sh->state);
3993                                         set_bit(STRIPE_HANDLE, &sh->state);
3994                                 }
3995                         }
3996                 }
3997                 if (rcw && conf->mddev->queue)
3998                         blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
3999                                           (unsigned long long)sh->sector,
4000                                           rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
4001         }
4002
4003         if (rcw > disks && rmw > disks &&
4004             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4005                 set_bit(STRIPE_DELAYED, &sh->state);
4006
4007         /* now if nothing is locked, and if we have enough data,
4008          * we can start a write request
4009          */
4010         /* since handle_stripe can be called at any time we need to handle the
4011          * case where a compute block operation has been submitted and then a
4012          * subsequent call wants to start a write request.  raid_run_ops only
4013          * handles the case where compute block and reconstruct are requested
4014          * simultaneously.  If this is not the case then new writes need to be
4015          * held off until the compute completes.
4016          */
4017         if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
4018             (s->locked == 0 && (rcw == 0 || rmw == 0) &&
4019              !test_bit(STRIPE_BIT_DELAY, &sh->state)))
4020                 schedule_reconstruction(sh, s, rcw == 0, 0);
4021         return 0;
4022 }
4023
4024 static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
4025                                 struct stripe_head_state *s, int disks)
4026 {
4027         struct r5dev *dev = NULL;
4028
4029         BUG_ON(sh->batch_head);
4030         set_bit(STRIPE_HANDLE, &sh->state);
4031
4032         switch (sh->check_state) {
4033         case check_state_idle:
4034                 /* start a new check operation if there are no failures */
4035                 if (s->failed == 0) {
4036                         BUG_ON(s->uptodate != disks);
4037                         sh->check_state = check_state_run;
4038                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4039                         clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4040                         s->uptodate--;
4041                         break;
4042                 }
4043                 dev = &sh->dev[s->failed_num[0]];
4044                 /* fall through */
4045         case check_state_compute_result:
4046                 sh->check_state = check_state_idle;
4047                 if (!dev)
4048                         dev = &sh->dev[sh->pd_idx];
4049
4050                 /* check that a write has not made the stripe insync */
4051                 if (test_bit(STRIPE_INSYNC, &sh->state))
4052                         break;
4053
4054                 /* either failed parity check, or recovery is happening */
4055                 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
4056                 BUG_ON(s->uptodate != disks);
4057
4058                 set_bit(R5_LOCKED, &dev->flags);
4059                 s->locked++;
4060                 set_bit(R5_Wantwrite, &dev->flags);
4061
4062                 clear_bit(STRIPE_DEGRADED, &sh->state);
4063                 set_bit(STRIPE_INSYNC, &sh->state);
4064                 break;
4065         case check_state_run:
4066                 break; /* we will be called again upon completion */
4067         case check_state_check_result:
4068                 sh->check_state = check_state_idle;
4069
4070                 /* if a failure occurred during the check operation, leave
4071                  * STRIPE_INSYNC not set and let the stripe be handled again
4072                  */
4073                 if (s->failed)
4074                         break;
4075
4076                 /* handle a successful check operation, if parity is correct
4077                  * we are done.  Otherwise update the mismatch count and repair
4078                  * parity if !MD_RECOVERY_CHECK
4079                  */
4080                 if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
4081                         /* parity is correct (on disc,
4082                          * not in buffer any more)
4083                          */
4084                         set_bit(STRIPE_INSYNC, &sh->state);
4085                 else {
4086                         atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
4087                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4088                                 /* don't try to repair!! */
4089                                 set_bit(STRIPE_INSYNC, &sh->state);
4090                                 pr_warn_ratelimited("%s: mismatch sector in range "
4091                                                     "%llu-%llu\n", mdname(conf->mddev),
4092                                                     (unsigned long long) sh->sector,
4093                                                     (unsigned long long) sh->sector +
4094                                                     STRIPE_SECTORS);
4095                         } else {
4096                                 sh->check_state = check_state_compute_run;
4097                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4098                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4099                                 set_bit(R5_Wantcompute,
4100                                         &sh->dev[sh->pd_idx].flags);
4101                                 sh->ops.target = sh->pd_idx;
4102                                 sh->ops.target2 = -1;
4103                                 s->uptodate++;
4104                         }
4105                 }
4106                 break;
4107         case check_state_compute_run:
4108                 break;
4109         default:
4110                 pr_err("%s: unknown check_state: %d sector: %llu\n",
4111                        __func__, sh->check_state,
4112                        (unsigned long long) sh->sector);
4113                 BUG();
4114         }
4115 }
4116
4117 static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
4118                                   struct stripe_head_state *s,
4119                                   int disks)
4120 {
4121         int pd_idx = sh->pd_idx;
4122         int qd_idx = sh->qd_idx;
4123         struct r5dev *dev;
4124
4125         BUG_ON(sh->batch_head);
4126         set_bit(STRIPE_HANDLE, &sh->state);
4127
4128         BUG_ON(s->failed > 2);
4129
4130         /* Want to check and possibly repair P and Q.
4131          * However there could be one 'failed' device, in which
4132          * case we can only check one of them, possibly using the
4133          * other to generate missing data
4134          */
4135
4136         switch (sh->check_state) {
4137         case check_state_idle:
4138                 /* start a new check operation if there are < 2 failures */
4139                 if (s->failed == s->q_failed) {
4140                         /* The only possible failed device holds Q, so it
4141                          * makes sense to check P (If anything else were failed,
4142                          * we would have used P to recreate it).
4143                          */
4144                         sh->check_state = check_state_run;
4145                 }
4146                 if (!s->q_failed && s->failed < 2) {
4147                         /* Q is not failed, and we didn't use it to generate
4148                          * anything, so it makes sense to check it
4149                          */
4150                         if (sh->check_state == check_state_run)
4151                                 sh->check_state = check_state_run_pq;
4152                         else
4153                                 sh->check_state = check_state_run_q;
4154                 }
4155
4156                 /* discard potentially stale zero_sum_result */
4157                 sh->ops.zero_sum_result = 0;
4158
4159                 if (sh->check_state == check_state_run) {
4160                         /* async_xor_zero_sum destroys the contents of P */
4161                         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
4162                         s->uptodate--;
4163                 }
4164                 if (sh->check_state >= check_state_run &&
4165                     sh->check_state <= check_state_run_pq) {
4166                         /* async_syndrome_zero_sum preserves P and Q, so
4167                          * no need to mark them !uptodate here
4168                          */
4169                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4170                         break;
4171                 }
4172
4173                 /* we have 2-disk failure */
4174                 BUG_ON(s->failed != 2);
4175                 /* fall through */
4176         case check_state_compute_result:
4177                 sh->check_state = check_state_idle;
4178
4179                 /* check that a write has not made the stripe insync */
4180                 if (test_bit(STRIPE_INSYNC, &sh->state))
4181                         break;
4182
4183                 /* now write out any block on a failed drive,
4184                  * or P or Q if they were recomputed
4185                  */
4186                 dev = NULL;
4187                 if (s->failed == 2) {
4188                         dev = &sh->dev[s->failed_num[1]];
4189                         s->locked++;
4190                         set_bit(R5_LOCKED, &dev->flags);
4191                         set_bit(R5_Wantwrite, &dev->flags);
4192                 }
4193                 if (s->failed >= 1) {
4194                         dev = &sh->dev[s->failed_num[0]];
4195                         s->locked++;
4196                         set_bit(R5_LOCKED, &dev->flags);
4197                         set_bit(R5_Wantwrite, &dev->flags);
4198                 }
4199                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4200                         dev = &sh->dev[pd_idx];
4201                         s->locked++;
4202                         set_bit(R5_LOCKED, &dev->flags);
4203                         set_bit(R5_Wantwrite, &dev->flags);
4204                 }
4205                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4206                         dev = &sh->dev[qd_idx];
4207                         s->locked++;
4208                         set_bit(R5_LOCKED, &dev->flags);
4209                         set_bit(R5_Wantwrite, &dev->flags);
4210                 }
4211                 if (WARN_ONCE(dev && !test_bit(R5_UPTODATE, &dev->flags),
4212                               "%s: disk%td not up to date\n",
4213                               mdname(conf->mddev),
4214                               dev - (struct r5dev *) &sh->dev)) {
4215                         clear_bit(R5_LOCKED, &dev->flags);
4216                         clear_bit(R5_Wantwrite, &dev->flags);
4217                         s->locked--;
4218                 }
4219                 clear_bit(STRIPE_DEGRADED, &sh->state);
4220
4221                 set_bit(STRIPE_INSYNC, &sh->state);
4222                 break;
4223         case check_state_run:
4224         case check_state_run_q:
4225         case check_state_run_pq:
4226                 break; /* we will be called again upon completion */
4227         case check_state_check_result:
4228                 sh->check_state = check_state_idle;
4229
4230                 /* handle a successful check operation, if parity is correct
4231                  * we are done.  Otherwise update the mismatch count and repair
4232                  * parity if !MD_RECOVERY_CHECK
4233                  */
4234                 if (sh->ops.zero_sum_result == 0) {
4235                         /* both parities are correct */
4236                         if (!s->failed)
4237                                 set_bit(STRIPE_INSYNC, &sh->state);
4238                         else {
4239                                 /* in contrast to the raid5 case we can validate
4240                                  * parity, but still have a failure to write
4241                                  * back
4242                                  */
4243                                 sh->check_state = check_state_compute_result;
4244                                 /* Returning at this point means that we may go
4245                                  * off and bring p and/or q uptodate again so
4246                                  * we make sure to check zero_sum_result again
4247                                  * to verify if p or q need writeback
4248                                  */
4249                         }
4250                 } else {
4251                         atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
4252                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4253                                 /* don't try to repair!! */
4254                                 set_bit(STRIPE_INSYNC, &sh->state);
4255                                 pr_warn_ratelimited("%s: mismatch sector in range "
4256                                                     "%llu-%llu\n", mdname(conf->mddev),
4257                                                     (unsigned long long) sh->sector,
4258                                                     (unsigned long long) sh->sector +
4259                                                     STRIPE_SECTORS);
4260                         } else {
4261                                 int *target = &sh->ops.target;
4262
4263                                 sh->ops.target = -1;
4264                                 sh->ops.target2 = -1;
4265                                 sh->check_state = check_state_compute_run;
4266                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4267                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4268                                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4269                                         set_bit(R5_Wantcompute,
4270                                                 &sh->dev[pd_idx].flags);
4271                                         *target = pd_idx;
4272                                         target = &sh->ops.target2;
4273                                         s->uptodate++;
4274                                 }
4275                                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4276                                         set_bit(R5_Wantcompute,
4277                                                 &sh->dev[qd_idx].flags);
4278                                         *target = qd_idx;
4279                                         s->uptodate++;
4280                                 }
4281                         }
4282                 }
4283                 break;
4284         case check_state_compute_run:
4285                 break;
4286         default:
4287                 pr_warn("%s: unknown check_state: %d sector: %llu\n",
4288                         __func__, sh->check_state,
4289                         (unsigned long long) sh->sector);
4290                 BUG();
4291         }
4292 }
4293
4294 static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
4295 {
4296         int i;
4297
4298         /* We have read all the blocks in this stripe and now we need to
4299          * copy some of them into a target stripe for expand.
4300          */
4301         struct dma_async_tx_descriptor *tx = NULL;
4302         BUG_ON(sh->batch_head);
4303         clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
4304         for (i = 0; i < sh->disks; i++)
4305                 if (i != sh->pd_idx && i != sh->qd_idx) {
4306                         int dd_idx, j;
4307                         struct stripe_head *sh2;
4308                         struct async_submit_ctl submit;
4309
4310                         sector_t bn = raid5_compute_blocknr(sh, i, 1);
4311                         sector_t s = raid5_compute_sector(conf, bn, 0,
4312                                                           &dd_idx, NULL);
4313                         sh2 = raid5_get_active_stripe(conf, s, 0, 1, 1);
4314                         if (sh2 == NULL)
4315                                 /* so far only the early blocks of this stripe
4316                                  * have been requested.  When later blocks
4317                                  * get requested, we will try again
4318                                  */
4319                                 continue;
4320                         if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
4321                            test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
4322                                 /* must have already done this block */
4323                                 raid5_release_stripe(sh2);
4324                                 continue;
4325                         }
4326
4327                         /* place all the copies on one channel */
4328                         init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
4329                         tx = async_memcpy(sh2->dev[dd_idx].page,
4330                                           sh->dev[i].page, 0, 0, STRIPE_SIZE,
4331                                           &submit);
4332
4333                         set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
4334                         set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
4335                         for (j = 0; j < conf->raid_disks; j++)
4336                                 if (j != sh2->pd_idx &&
4337                                     j != sh2->qd_idx &&
4338                                     !test_bit(R5_Expanded, &sh2->dev[j].flags))
4339                                         break;
4340                         if (j == conf->raid_disks) {
4341                                 set_bit(STRIPE_EXPAND_READY, &sh2->state);
4342                                 set_bit(STRIPE_HANDLE, &sh2->state);
4343                         }
4344                         raid5_release_stripe(sh2);
4345
4346                 }
4347         /* done submitting copies, wait for them to complete */
4348         async_tx_quiesce(&tx);
4349 }
4350
4351 /*
4352  * handle_stripe - do things to a stripe.
4353  *
4354  * We lock the stripe by setting STRIPE_ACTIVE and then examine the
4355  * state of various bits to see what needs to be done.
4356  * Possible results:
4357  *    return some read requests which now have data
4358  *    return some write requests which are safely on storage
4359  *    schedule a read on some buffers
4360  *    schedule a write of some buffers
4361  *    return confirmation of parity correctness
4362  *
4363  */
4364
4365 static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
4366 {
4367         struct r5conf *conf = sh->raid_conf;
4368         int disks = sh->disks;
4369         struct r5dev *dev;
4370         int i;
4371         int do_recovery = 0;
4372
4373         memset(s, 0, sizeof(*s));
4374
4375         s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state) && !sh->batch_head;
4376         s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state) && !sh->batch_head;
4377         s->failed_num[0] = -1;
4378         s->failed_num[1] = -1;
4379         s->log_failed = r5l_log_disk_error(conf);
4380
4381         /* Now to look around and see what can be done */
4382         rcu_read_lock();
4383         for (i=disks; i--; ) {
4384                 struct md_rdev *rdev;
4385                 sector_t first_bad;
4386                 int bad_sectors;
4387                 int is_bad = 0;
4388
4389                 dev = &sh->dev[i];
4390
4391                 pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
4392                          i, dev->flags,
4393                          dev->toread, dev->towrite, dev->written);
4394                 /* maybe we can reply to a read
4395                  *
4396                  * new wantfill requests are only permitted while
4397                  * ops_complete_biofill is guaranteed to be inactive
4398                  */
4399                 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
4400                     !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
4401                         set_bit(R5_Wantfill, &dev->flags);
4402
4403                 /* now count some things */
4404                 if (test_bit(R5_LOCKED, &dev->flags))
4405                         s->locked++;
4406                 if (test_bit(R5_UPTODATE, &dev->flags))
4407                         s->uptodate++;
4408                 if (test_bit(R5_Wantcompute, &dev->flags)) {
4409                         s->compute++;
4410                         BUG_ON(s->compute > 2);
4411                 }
4412
4413                 if (test_bit(R5_Wantfill, &dev->flags))
4414                         s->to_fill++;
4415                 else if (dev->toread)
4416                         s->to_read++;
4417                 if (dev->towrite) {
4418                         s->to_write++;
4419                         if (!test_bit(R5_OVERWRITE, &dev->flags))
4420                                 s->non_overwrite++;
4421                 }
4422                 if (dev->written)
4423                         s->written++;
4424                 /* Prefer to use the replacement for reads, but only
4425                  * if it is recovered enough and has no bad blocks.
4426                  */
4427                 rdev = rcu_dereference(conf->disks[i].replacement);
4428                 if (rdev && !test_bit(Faulty, &rdev->flags) &&
4429                     rdev->recovery_offset >= sh->sector + STRIPE_SECTORS &&
4430                     !is_badblock(rdev, sh->sector, STRIPE_SECTORS,
4431                                  &first_bad, &bad_sectors))
4432                         set_bit(R5_ReadRepl, &dev->flags);
4433                 else {
4434                         if (rdev && !test_bit(Faulty, &rdev->flags))
4435                                 set_bit(R5_NeedReplace, &dev->flags);
4436                         else
4437                                 clear_bit(R5_NeedReplace, &dev->flags);
4438                         rdev = rcu_dereference(conf->disks[i].rdev);
4439                         clear_bit(R5_ReadRepl, &dev->flags);
4440                 }
4441                 if (rdev && test_bit(Faulty, &rdev->flags))
4442                         rdev = NULL;
4443                 if (rdev) {
4444                         is_bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
4445                                              &first_bad, &bad_sectors);
4446                         if (s->blocked_rdev == NULL
4447                             && (test_bit(Blocked, &rdev->flags)
4448                                 || is_bad < 0)) {
4449                                 if (is_bad < 0)
4450                                         set_bit(BlockedBadBlocks,
4451                                                 &rdev->flags);
4452                                 s->blocked_rdev = rdev;
4453                                 atomic_inc(&rdev->nr_pending);
4454                         }
4455                 }
4456                 clear_bit(R5_Insync, &dev->flags);
4457                 if (!rdev)
4458                         /* Not in-sync */;
4459                 else if (is_bad) {
4460                         /* also not in-sync */
4461                         if (!test_bit(WriteErrorSeen, &rdev->flags) &&
4462                             test_bit(R5_UPTODATE, &dev->flags)) {
4463                                 /* treat as in-sync, but with a read error
4464                                  * which we can now try to correct
4465                                  */
4466                                 set_bit(R5_Insync, &dev->flags);
4467                                 set_bit(R5_ReadError, &dev->flags);
4468                         }
4469                 } else if (test_bit(In_sync, &rdev->flags))
4470                         set_bit(R5_Insync, &dev->flags);
4471                 else if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
4472                         /* in sync if before recovery_offset */
4473                         set_bit(R5_Insync, &dev->flags);
4474                 else if (test_bit(R5_UPTODATE, &dev->flags) &&
4475                          test_bit(R5_Expanded, &dev->flags))
4476                         /* If we've reshaped into here, we assume it is Insync.
4477                          * We will shortly update recovery_offset to make
4478                          * it official.
4479                          */
4480                         set_bit(R5_Insync, &dev->flags);
4481
4482                 if (test_bit(R5_WriteError, &dev->flags)) {
4483                         /* This flag does not apply to '.replacement'
4484                          * only to .rdev, so make sure to check that*/
4485                         struct md_rdev *rdev2 = rcu_dereference(
4486                                 conf->disks[i].rdev);
4487                         if (rdev2 == rdev)
4488                                 clear_bit(R5_Insync, &dev->flags);
4489                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4490                                 s->handle_bad_blocks = 1;
4491                                 atomic_inc(&rdev2->nr_pending);
4492                         } else
4493                                 clear_bit(R5_WriteError, &dev->flags);
4494                 }
4495                 if (test_bit(R5_MadeGood, &dev->flags)) {
4496                         /* This flag does not apply to '.replacement'
4497                          * only to .rdev, so make sure to check that*/
4498                         struct md_rdev *rdev2 = rcu_dereference(
4499                                 conf->disks[i].rdev);
4500                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4501                                 s->handle_bad_blocks = 1;
4502                                 atomic_inc(&rdev2->nr_pending);
4503                         } else
4504                                 clear_bit(R5_MadeGood, &dev->flags);
4505                 }
4506                 if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
4507                         struct md_rdev *rdev2 = rcu_dereference(
4508                                 conf->disks[i].replacement);
4509                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4510                                 s->handle_bad_blocks = 1;
4511                                 atomic_inc(&rdev2->nr_pending);
4512                         } else
4513                                 clear_bit(R5_MadeGoodRepl, &dev->flags);
4514                 }
4515                 if (!test_bit(R5_Insync, &dev->flags)) {
4516                         /* The ReadError flag will just be confusing now */
4517                         clear_bit(R5_ReadError, &dev->flags);
4518                         clear_bit(R5_ReWrite, &dev->flags);
4519                 }
4520                 if (test_bit(R5_ReadError, &dev->flags))
4521                         clear_bit(R5_Insync, &dev->flags);
4522                 if (!test_bit(R5_Insync, &dev->flags)) {
4523                         if (s->failed < 2)
4524                                 s->failed_num[s->failed] = i;
4525                         s->failed++;
4526                         if (rdev && !test_bit(Faulty, &rdev->flags))
4527                                 do_recovery = 1;
4528                         else if (!rdev) {
4529                                 rdev = rcu_dereference(
4530                                     conf->disks[i].replacement);
4531                                 if (rdev && !test_bit(Faulty, &rdev->flags))
4532                                         do_recovery = 1;
4533                         }
4534                 }
4535
4536                 if (test_bit(R5_InJournal, &dev->flags))
4537                         s->injournal++;
4538                 if (test_bit(R5_InJournal, &dev->flags) && dev->written)
4539                         s->just_cached++;
4540         }
4541         if (test_bit(STRIPE_SYNCING, &sh->state)) {
4542                 /* If there is a failed device being replaced,
4543                  *     we must be recovering.
4544                  * else if we are after recovery_cp, we must be syncing
4545                  * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
4546                  * else we can only be replacing
4547                  * sync and recovery both need to read all devices, and so
4548                  * use the same flag.
4549                  */
4550                 if (do_recovery ||
4551                     sh->sector >= conf->mddev->recovery_cp ||
4552                     test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
4553                         s->syncing = 1;
4554                 else
4555                         s->replacing = 1;
4556         }
4557         rcu_read_unlock();
4558 }
4559
4560 static int clear_batch_ready(struct stripe_head *sh)
4561 {
4562         /* Return '1' if this is a member of batch, or
4563          * '0' if it is a lone stripe or a head which can now be
4564          * handled.
4565          */
4566         struct stripe_head *tmp;
4567         if (!test_and_clear_bit(STRIPE_BATCH_READY, &sh->state))
4568                 return (sh->batch_head && sh->batch_head != sh);
4569         spin_lock(&sh->stripe_lock);
4570         if (!sh->batch_head) {
4571                 spin_unlock(&sh->stripe_lock);
4572                 return 0;
4573         }
4574
4575         /*
4576          * this stripe could be added to a batch list before we check
4577          * BATCH_READY, skips it
4578          */
4579         if (sh->batch_head != sh) {
4580                 spin_unlock(&sh->stripe_lock);
4581                 return 1;
4582         }
4583         spin_lock(&sh->batch_lock);
4584         list_for_each_entry(tmp, &sh->batch_list, batch_list)
4585                 clear_bit(STRIPE_BATCH_READY, &tmp->state);
4586         spin_unlock(&sh->batch_lock);
4587         spin_unlock(&sh->stripe_lock);
4588
4589         /*
4590          * BATCH_READY is cleared, no new stripes can be added.
4591          * batch_list can be accessed without lock
4592          */
4593         return 0;
4594 }
4595
4596 static void break_stripe_batch_list(struct stripe_head *head_sh,
4597                                     unsigned long handle_flags)
4598 {
4599         struct stripe_head *sh, *next;
4600         int i;
4601         int do_wakeup = 0;
4602
4603         list_for_each_entry_safe(sh, next, &head_sh->batch_list, batch_list) {
4604
4605                 list_del_init(&sh->batch_list);
4606
4607                 WARN_ONCE(sh->state & ((1 << STRIPE_ACTIVE) |
4608                                           (1 << STRIPE_SYNCING) |
4609                                           (1 << STRIPE_REPLACED) |
4610                                           (1 << STRIPE_DELAYED) |
4611                                           (1 << STRIPE_BIT_DELAY) |
4612                                           (1 << STRIPE_FULL_WRITE) |
4613                                           (1 << STRIPE_BIOFILL_RUN) |
4614                                           (1 << STRIPE_COMPUTE_RUN)  |
4615                                           (1 << STRIPE_OPS_REQ_PENDING) |
4616                                           (1 << STRIPE_DISCARD) |
4617                                           (1 << STRIPE_BATCH_READY) |
4618                                           (1 << STRIPE_BATCH_ERR) |
4619                                           (1 << STRIPE_BITMAP_PENDING)),
4620                         "stripe state: %lx\n", sh->state);
4621                 WARN_ONCE(head_sh->state & ((1 << STRIPE_DISCARD) |
4622                                               (1 << STRIPE_REPLACED)),
4623                         "head stripe state: %lx\n", head_sh->state);
4624
4625                 set_mask_bits(&sh->state, ~(STRIPE_EXPAND_SYNC_FLAGS |
4626                                             (1 << STRIPE_PREREAD_ACTIVE) |
4627                                             (1 << STRIPE_DEGRADED) |
4628                                             (1 << STRIPE_ON_UNPLUG_LIST)),
4629                               head_sh->state & (1 << STRIPE_INSYNC));
4630
4631                 sh->check_state = head_sh->check_state;
4632                 sh->reconstruct_state = head_sh->reconstruct_state;
4633                 spin_lock_irq(&sh->stripe_lock);
4634                 sh->batch_head = NULL;
4635                 spin_unlock_irq(&sh->stripe_lock);
4636                 for (i = 0; i < sh->disks; i++) {
4637                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
4638                                 do_wakeup = 1;
4639                         sh->dev[i].flags = head_sh->dev[i].flags &
4640                                 (~((1 << R5_WriteError) | (1 << R5_Overlap)));
4641                 }
4642                 if (handle_flags == 0 ||
4643                     sh->state & handle_flags)
4644                         set_bit(STRIPE_HANDLE, &sh->state);
4645                 raid5_release_stripe(sh);
4646         }
4647         spin_lock_irq(&head_sh->stripe_lock);
4648         head_sh->batch_head = NULL;
4649         spin_unlock_irq(&head_sh->stripe_lock);
4650         for (i = 0; i < head_sh->disks; i++)
4651                 if (test_and_clear_bit(R5_Overlap, &head_sh->dev[i].flags))
4652                         do_wakeup = 1;
4653         if (head_sh->state & handle_flags)
4654                 set_bit(STRIPE_HANDLE, &head_sh->state);
4655
4656         if (do_wakeup)
4657                 wake_up(&head_sh->raid_conf->wait_for_overlap);
4658 }
4659
4660 static void handle_stripe(struct stripe_head *sh)
4661 {
4662         struct stripe_head_state s;
4663         struct r5conf *conf = sh->raid_conf;
4664         int i;
4665         int prexor;
4666         int disks = sh->disks;
4667         struct r5dev *pdev, *qdev;
4668
4669         clear_bit(STRIPE_HANDLE, &sh->state);
4670         if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
4671                 /* already being handled, ensure it gets handled
4672                  * again when current action finishes */
4673                 set_bit(STRIPE_HANDLE, &sh->state);
4674                 return;
4675         }
4676
4677         if (clear_batch_ready(sh) ) {
4678                 clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
4679                 return;
4680         }
4681
4682         if (test_and_clear_bit(STRIPE_BATCH_ERR, &sh->state))
4683                 break_stripe_batch_list(sh, 0);
4684
4685         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) && !sh->batch_head) {
4686                 spin_lock(&sh->stripe_lock);
4687                 /*
4688                  * Cannot process 'sync' concurrently with 'discard'.
4689                  * Flush data in r5cache before 'sync'.
4690                  */
4691                 if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) &&
4692                     !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) &&
4693                     !test_bit(STRIPE_DISCARD, &sh->state) &&
4694                     test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
4695                         set_bit(STRIPE_SYNCING, &sh->state);
4696                         clear_bit(STRIPE_INSYNC, &sh->state);
4697                         clear_bit(STRIPE_REPLACED, &sh->state);
4698                 }
4699                 spin_unlock(&sh->stripe_lock);
4700         }
4701         clear_bit(STRIPE_DELAYED, &sh->state);
4702
4703         pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
4704                 "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
4705                (unsigned long long)sh->sector, sh->state,
4706                atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
4707                sh->check_state, sh->reconstruct_state);
4708
4709         analyse_stripe(sh, &s);
4710
4711         if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
4712                 goto finish;
4713
4714         if (s.handle_bad_blocks ||
4715             test_bit(MD_SB_CHANGE_PENDING, &conf->mddev->sb_flags)) {
4716                 set_bit(STRIPE_HANDLE, &sh->state);
4717                 goto finish;
4718         }
4719
4720         if (unlikely(s.blocked_rdev)) {
4721                 if (s.syncing || s.expanding || s.expanded ||
4722                     s.replacing || s.to_write || s.written) {
4723                         set_bit(STRIPE_HANDLE, &sh->state);
4724                         goto finish;
4725                 }
4726                 /* There is nothing for the blocked_rdev to block */
4727                 rdev_dec_pending(s.blocked_rdev, conf->mddev);
4728                 s.blocked_rdev = NULL;
4729         }
4730
4731         if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
4732                 set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
4733                 set_bit(STRIPE_BIOFILL_RUN, &sh->state);
4734         }
4735
4736         pr_debug("locked=%d uptodate=%d to_read=%d"
4737                " to_write=%d failed=%d failed_num=%d,%d\n",
4738                s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
4739                s.failed_num[0], s.failed_num[1]);
4740         /*
4741          * check if the array has lost more than max_degraded devices and,
4742          * if so, some requests might need to be failed.
4743          *
4744          * When journal device failed (log_failed), we will only process
4745          * the stripe if there is data need write to raid disks
4746          */
4747         if (s.failed > conf->max_degraded ||
4748             (s.log_failed && s.injournal == 0)) {
4749                 sh->check_state = 0;
4750                 sh->reconstruct_state = 0;
4751                 break_stripe_batch_list(sh, 0);
4752                 if (s.to_read+s.to_write+s.written)
4753                         handle_failed_stripe(conf, sh, &s, disks);
4754                 if (s.syncing + s.replacing)
4755                         handle_failed_sync(conf, sh, &s);
4756         }
4757
4758         /* Now we check to see if any write operations have recently
4759          * completed
4760          */
4761         prexor = 0;
4762         if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
4763                 prexor = 1;
4764         if (sh->reconstruct_state == reconstruct_state_drain_result ||
4765             sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
4766                 sh->reconstruct_state = reconstruct_state_idle;
4767
4768                 /* All the 'written' buffers and the parity block are ready to
4769                  * be written back to disk
4770                  */
4771                 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
4772                        !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
4773                 BUG_ON(sh->qd_idx >= 0 &&
4774                        !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
4775                        !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
4776                 for (i = disks; i--; ) {
4777                         struct r5dev *dev = &sh->dev[i];
4778                         if (test_bit(R5_LOCKED, &dev->flags) &&
4779                                 (i == sh->pd_idx || i == sh->qd_idx ||
4780                                  dev->written || test_bit(R5_InJournal,
4781                                                           &dev->flags))) {
4782                                 pr_debug("Writing block %d\n", i);
4783                                 set_bit(R5_Wantwrite, &dev->flags);
4784                                 if (prexor)
4785                                         continue;
4786                                 if (s.failed > 1)
4787                                         continue;
4788                                 if (!test_bit(R5_Insync, &dev->flags) ||
4789                                     ((i == sh->pd_idx || i == sh->qd_idx)  &&
4790                                      s.failed == 0))
4791                                         set_bit(STRIPE_INSYNC, &sh->state);
4792                         }
4793                 }
4794                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4795                         s.dec_preread_active = 1;
4796         }
4797
4798         /*
4799          * might be able to return some write requests if the parity blocks
4800          * are safe, or on a failed drive
4801          */
4802         pdev = &sh->dev[sh->pd_idx];
4803         s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
4804                 || (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
4805         qdev = &sh->dev[sh->qd_idx];
4806         s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
4807                 || (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
4808                 || conf->level < 6;
4809
4810         if (s.written &&
4811             (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
4812                              && !test_bit(R5_LOCKED, &pdev->flags)
4813                              && (test_bit(R5_UPTODATE, &pdev->flags) ||
4814                                  test_bit(R5_Discard, &pdev->flags))))) &&
4815             (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
4816                              && !test_bit(R5_LOCKED, &qdev->flags)
4817                              && (test_bit(R5_UPTODATE, &qdev->flags) ||
4818                                  test_bit(R5_Discard, &qdev->flags))))))
4819                 handle_stripe_clean_event(conf, sh, disks);
4820
4821         if (s.just_cached)
4822                 r5c_handle_cached_data_endio(conf, sh, disks);
4823         log_stripe_write_finished(sh);
4824
4825         /* Now we might consider reading some blocks, either to check/generate
4826          * parity, or to satisfy requests
4827          * or to load a block that is being partially written.
4828          */
4829         if (s.to_read || s.non_overwrite
4830             || (conf->level == 6 && s.to_write && s.failed)
4831             || (s.syncing && (s.uptodate + s.compute < disks))
4832             || s.replacing
4833             || s.expanding)
4834                 handle_stripe_fill(sh, &s, disks);
4835
4836         /*
4837          * When the stripe finishes full journal write cycle (write to journal
4838          * and raid disk), this is the clean up procedure so it is ready for
4839          * next operation.
4840          */
4841         r5c_finish_stripe_write_out(conf, sh, &s);
4842
4843         /*
4844          * Now to consider new write requests, cache write back and what else,
4845          * if anything should be read.  We do not handle new writes when:
4846          * 1/ A 'write' operation (copy+xor) is already in flight.
4847          * 2/ A 'check' operation is in flight, as it may clobber the parity
4848          *    block.
4849          * 3/ A r5c cache log write is in flight.
4850          */
4851
4852         if (!sh->reconstruct_state && !sh->check_state && !sh->log_io) {
4853                 if (!r5c_is_writeback(conf->log)) {
4854                         if (s.to_write)
4855                                 handle_stripe_dirtying(conf, sh, &s, disks);
4856                 } else { /* write back cache */
4857                         int ret = 0;
4858
4859                         /* First, try handle writes in caching phase */
4860                         if (s.to_write)
4861                                 ret = r5c_try_caching_write(conf, sh, &s,
4862                                                             disks);
4863                         /*
4864                          * If caching phase failed: ret == -EAGAIN
4865                          *    OR
4866                          * stripe under reclaim: !caching && injournal
4867                          *
4868                          * fall back to handle_stripe_dirtying()
4869                          */
4870                         if (ret == -EAGAIN ||
4871                             /* stripe under reclaim: !caching && injournal */
4872                             (!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
4873                              s.injournal > 0)) {
4874                                 ret = handle_stripe_dirtying(conf, sh, &s,
4875                                                              disks);
4876                                 if (ret == -EAGAIN)
4877                                         goto finish;
4878                         }
4879                 }
4880         }
4881
4882         /* maybe we need to check and possibly fix the parity for this stripe
4883          * Any reads will already have been scheduled, so we just see if enough
4884          * data is available.  The parity check is held off while parity
4885          * dependent operations are in flight.
4886          */
4887         if (sh->check_state ||
4888             (s.syncing && s.locked == 0 &&
4889              !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4890              !test_bit(STRIPE_INSYNC, &sh->state))) {
4891                 if (conf->level == 6)
4892                         handle_parity_checks6(conf, sh, &s, disks);
4893                 else
4894                         handle_parity_checks5(conf, sh, &s, disks);
4895         }
4896
4897         if ((s.replacing || s.syncing) && s.locked == 0
4898             && !test_bit(STRIPE_COMPUTE_RUN, &sh->state)
4899             && !test_bit(STRIPE_REPLACED, &sh->state)) {
4900                 /* Write out to replacement devices where possible */
4901                 for (i = 0; i < conf->raid_disks; i++)
4902                         if (test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
4903                                 WARN_ON(!test_bit(R5_UPTODATE, &sh->dev[i].flags));
4904                                 set_bit(R5_WantReplace, &sh->dev[i].flags);
4905                                 set_bit(R5_LOCKED, &sh->dev[i].flags);
4906                                 s.locked++;
4907                         }
4908                 if (s.replacing)
4909                         set_bit(STRIPE_INSYNC, &sh->state);
4910                 set_bit(STRIPE_REPLACED, &sh->state);
4911         }
4912         if ((s.syncing || s.replacing) && s.locked == 0 &&
4913             !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4914             test_bit(STRIPE_INSYNC, &sh->state)) {
4915                 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
4916                 clear_bit(STRIPE_SYNCING, &sh->state);
4917                 if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
4918                         wake_up(&conf->wait_for_overlap);
4919         }
4920
4921         /* If the failed drives are just a ReadError, then we might need
4922          * to progress the repair/check process
4923          */
4924         if (s.failed <= conf->max_degraded && !conf->mddev->ro)
4925                 for (i = 0; i < s.failed; i++) {
4926                         struct r5dev *dev = &sh->dev[s.failed_num[i]];
4927                         if (test_bit(R5_ReadError, &dev->flags)
4928                             && !test_bit(R5_LOCKED, &dev->flags)
4929                             && test_bit(R5_UPTODATE, &dev->flags)
4930                                 ) {
4931                                 if (!test_bit(R5_ReWrite, &dev->flags)) {
4932                                         set_bit(R5_Wantwrite, &dev->flags);
4933                                         set_bit(R5_ReWrite, &dev->flags);
4934                                         set_bit(R5_LOCKED, &dev->flags);
4935                                         s.locked++;
4936                                 } else {
4937                                         /* let's read it back */
4938                                         set_bit(R5_Wantread, &dev->flags);
4939                                         set_bit(R5_LOCKED, &dev->flags);
4940                                         s.locked++;
4941                                 }
4942                         }
4943                 }
4944
4945         /* Finish reconstruct operations initiated by the expansion process */
4946         if (sh->reconstruct_state == reconstruct_state_result) {
4947                 struct stripe_head *sh_src
4948                         = raid5_get_active_stripe(conf, sh->sector, 1, 1, 1);
4949                 if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
4950                         /* sh cannot be written until sh_src has been read.
4951                          * so arrange for sh to be delayed a little
4952                          */
4953                         set_bit(STRIPE_DELAYED, &sh->state);
4954                         set_bit(STRIPE_HANDLE, &sh->state);
4955                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
4956                                               &sh_src->state))
4957                                 atomic_inc(&conf->preread_active_stripes);
4958                         raid5_release_stripe(sh_src);
4959                         goto finish;
4960                 }
4961                 if (sh_src)
4962                         raid5_release_stripe(sh_src);
4963
4964                 sh->reconstruct_state = reconstruct_state_idle;
4965                 clear_bit(STRIPE_EXPANDING, &sh->state);
4966                 for (i = conf->raid_disks; i--; ) {
4967                         set_bit(R5_Wantwrite, &sh->dev[i].flags);
4968                         set_bit(R5_LOCKED, &sh->dev[i].flags);
4969                         s.locked++;
4970                 }
4971         }
4972
4973         if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
4974             !sh->reconstruct_state) {
4975                 /* Need to write out all blocks after computing parity */
4976                 sh->disks = conf->raid_disks;
4977                 stripe_set_idx(sh->sector, conf, 0, sh);
4978                 schedule_reconstruction(sh, &s, 1, 1);
4979         } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
4980                 clear_bit(STRIPE_EXPAND_READY, &sh->state);
4981                 atomic_dec(&conf->reshape_stripes);
4982                 wake_up(&conf->wait_for_overlap);
4983                 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
4984         }
4985
4986         if (s.expanding && s.locked == 0 &&
4987             !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
4988                 handle_stripe_expansion(conf, sh);
4989
4990 finish:
4991         /* wait for this device to become unblocked */
4992         if (unlikely(s.blocked_rdev)) {
4993                 if (conf->mddev->external)
4994                         md_wait_for_blocked_rdev(s.blocked_rdev,
4995                                                  conf->mddev);
4996                 else
4997                         /* Internal metadata will immediately
4998                          * be written by raid5d, so we don't
4999                          * need to wait here.
5000                          */
5001                         rdev_dec_pending(s.blocked_rdev,
5002                                          conf->mddev);
5003         }
5004
5005         if (s.handle_bad_blocks)
5006                 for (i = disks; i--; ) {
5007                         struct md_rdev *rdev;
5008                         struct r5dev *dev = &sh->dev[i];
5009                         if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
5010                                 /* We own a safe reference to the rdev */
5011                                 rdev = conf->disks[i].rdev;
5012                                 if (!rdev_set_badblocks(rdev, sh->sector,
5013                                                         STRIPE_SECTORS, 0))
5014                                         md_error(conf->mddev, rdev);
5015                                 rdev_dec_pending(rdev, conf->mddev);
5016                         }
5017                         if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
5018                                 rdev = conf->disks[i].rdev;
5019                                 rdev_clear_badblocks(rdev, sh->sector,
5020                                                      STRIPE_SECTORS, 0);
5021                                 rdev_dec_pending(rdev, conf->mddev);
5022                         }
5023                         if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
5024                                 rdev = conf->disks[i].replacement;
5025                                 if (!rdev)
5026                                         /* rdev have been moved down */
5027                                         rdev = conf->disks[i].rdev;
5028                                 rdev_clear_badblocks(rdev, sh->sector,
5029                                                      STRIPE_SECTORS, 0);
5030                                 rdev_dec_pending(rdev, conf->mddev);
5031                         }
5032                 }
5033
5034         if (s.ops_request)
5035                 raid_run_ops(sh, s.ops_request);
5036
5037         ops_run_io(sh, &s);
5038
5039         if (s.dec_preread_active) {
5040                 /* We delay this until after ops_run_io so that if make_request
5041                  * is waiting on a flush, it won't continue until the writes
5042                  * have actually been submitted.
5043                  */
5044                 atomic_dec(&conf->preread_active_stripes);
5045                 if (atomic_read(&conf->preread_active_stripes) <
5046                     IO_THRESHOLD)
5047                         md_wakeup_thread(conf->mddev->thread);
5048         }
5049
5050         clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
5051 }
5052
5053 static void raid5_activate_delayed(struct r5conf *conf)
5054 {
5055         if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
5056                 while (!list_empty(&conf->delayed_list)) {
5057                         struct list_head *l = conf->delayed_list.next;
5058                         struct stripe_head *sh;
5059                         sh = list_entry(l, struct stripe_head, lru);
5060                         list_del_init(l);
5061                         clear_bit(STRIPE_DELAYED, &sh->state);
5062                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5063                                 atomic_inc(&conf->preread_active_stripes);
5064                         list_add_tail(&sh->lru, &conf->hold_list);
5065                         raid5_wakeup_stripe_thread(sh);
5066                 }
5067         }
5068 }
5069
5070 static void activate_bit_delay(struct r5conf *conf,
5071         struct list_head *temp_inactive_list)
5072 {
5073         /* device_lock is held */
5074         struct list_head head;
5075         list_add(&head, &conf->bitmap_list);
5076         list_del_init(&conf->bitmap_list);
5077         while (!list_empty(&head)) {
5078                 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
5079                 int hash;
5080                 list_del_init(&sh->lru);
5081                 atomic_inc(&sh->count);
5082                 hash = sh->hash_lock_index;
5083                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
5084         }
5085 }
5086
5087 static int raid5_congested(struct mddev *mddev, int bits)
5088 {
5089         struct r5conf *conf = mddev->private;
5090
5091         /* No difference between reads and writes.  Just check
5092          * how busy the stripe_cache is
5093          */
5094
5095         if (test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
5096                 return 1;
5097
5098         /* Also checks whether there is pressure on r5cache log space */
5099         if (test_bit(R5C_LOG_TIGHT, &conf->cache_state))
5100                 return 1;
5101         if (conf->quiesce)
5102                 return 1;
5103         if (atomic_read(&conf->empty_inactive_list_nr))
5104                 return 1;
5105
5106         return 0;
5107 }
5108
5109 static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
5110 {
5111         struct r5conf *conf = mddev->private;
5112         sector_t sector = bio->bi_iter.bi_sector;
5113         unsigned int chunk_sectors;
5114         unsigned int bio_sectors = bio_sectors(bio);
5115
5116         WARN_ON_ONCE(bio->bi_partno);
5117
5118         chunk_sectors = min(conf->chunk_sectors, conf->prev_chunk_sectors);
5119         return  chunk_sectors >=
5120                 ((sector & (chunk_sectors - 1)) + bio_sectors);
5121 }
5122
5123 /*
5124  *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
5125  *  later sampled by raid5d.
5126  */
5127 static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
5128 {
5129         unsigned long flags;
5130
5131         spin_lock_irqsave(&conf->device_lock, flags);
5132
5133         bi->bi_next = conf->retry_read_aligned_list;
5134         conf->retry_read_aligned_list = bi;
5135
5136         spin_unlock_irqrestore(&conf->device_lock, flags);
5137         md_wakeup_thread(conf->mddev->thread);
5138 }
5139
5140 static struct bio *remove_bio_from_retry(struct r5conf *conf,
5141                                          unsigned int *offset)
5142 {
5143         struct bio *bi;
5144
5145         bi = conf->retry_read_aligned;
5146         if (bi) {
5147                 *offset = conf->retry_read_offset;
5148                 conf->retry_read_aligned = NULL;
5149                 return bi;
5150         }
5151         bi = conf->retry_read_aligned_list;
5152         if(bi) {
5153                 conf->retry_read_aligned_list = bi->bi_next;
5154                 bi->bi_next = NULL;
5155                 *offset = 0;
5156         }
5157
5158         return bi;
5159 }
5160
5161 /*
5162  *  The "raid5_align_endio" should check if the read succeeded and if it
5163  *  did, call bio_endio on the original bio (having bio_put the new bio
5164  *  first).
5165  *  If the read failed..
5166  */
5167 static void raid5_align_endio(struct bio *bi)
5168 {
5169         struct bio* raid_bi  = bi->bi_private;
5170         struct mddev *mddev;
5171         struct r5conf *conf;
5172         struct md_rdev *rdev;
5173         blk_status_t error = bi->bi_status;
5174
5175         bio_put(bi);
5176
5177         rdev = (void*)raid_bi->bi_next;
5178         raid_bi->bi_next = NULL;
5179         mddev = rdev->mddev;
5180         conf = mddev->private;
5181
5182         rdev_dec_pending(rdev, conf->mddev);
5183
5184         if (!error) {
5185                 bio_endio(raid_bi);
5186                 if (atomic_dec_and_test(&conf->active_aligned_reads))
5187                         wake_up(&conf->wait_for_quiescent);
5188                 return;
5189         }
5190
5191         pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
5192
5193         add_bio_to_retry(raid_bi, conf);
5194 }
5195
5196 static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
5197 {
5198         struct r5conf *conf = mddev->private;
5199         int dd_idx;
5200         struct bio* align_bi;
5201         struct md_rdev *rdev;
5202         sector_t end_sector;
5203
5204         if (!in_chunk_boundary(mddev, raid_bio)) {
5205                 pr_debug("%s: non aligned\n", __func__);
5206                 return 0;
5207         }
5208         /*
5209          * use bio_clone_fast to make a copy of the bio
5210          */
5211         align_bi = bio_clone_fast(raid_bio, GFP_NOIO, &mddev->bio_set);
5212         if (!align_bi)
5213                 return 0;
5214         /*
5215          *   set bi_end_io to a new function, and set bi_private to the
5216          *     original bio.
5217          */
5218         align_bi->bi_end_io  = raid5_align_endio;
5219         align_bi->bi_private = raid_bio;
5220         /*
5221          *      compute position
5222          */
5223         align_bi->bi_iter.bi_sector =
5224                 raid5_compute_sector(conf, raid_bio->bi_iter.bi_sector,
5225                                      0, &dd_idx, NULL);
5226
5227         end_sector = bio_end_sector(align_bi);
5228         rcu_read_lock();
5229         rdev = rcu_dereference(conf->disks[dd_idx].replacement);
5230         if (!rdev || test_bit(Faulty, &rdev->flags) ||
5231             rdev->recovery_offset < end_sector) {
5232                 rdev = rcu_dereference(conf->disks[dd_idx].rdev);
5233                 if (rdev &&
5234                     (test_bit(Faulty, &rdev->flags) ||
5235                     !(test_bit(In_sync, &rdev->flags) ||
5236                       rdev->recovery_offset >= end_sector)))
5237                         rdev = NULL;
5238         }
5239
5240         if (r5c_big_stripe_cached(conf, align_bi->bi_iter.bi_sector)) {
5241                 rcu_read_unlock();
5242                 bio_put(align_bi);
5243                 return 0;
5244         }
5245
5246         if (rdev) {
5247                 sector_t first_bad;
5248                 int bad_sectors;
5249
5250                 atomic_inc(&rdev->nr_pending);
5251                 rcu_read_unlock();
5252                 raid_bio->bi_next = (void*)rdev;
5253                 bio_set_dev(align_bi, rdev->bdev);
5254
5255                 if (is_badblock(rdev, align_bi->bi_iter.bi_sector,
5256                                 bio_sectors(align_bi),
5257                                 &first_bad, &bad_sectors)) {
5258                         bio_put(align_bi);
5259                         rdev_dec_pending(rdev, mddev);
5260                         return 0;
5261                 }
5262
5263                 /* No reshape active, so we can trust rdev->data_offset */
5264                 align_bi->bi_iter.bi_sector += rdev->data_offset;
5265
5266                 spin_lock_irq(&conf->device_lock);
5267                 wait_event_lock_irq(conf->wait_for_quiescent,
5268                                     conf->quiesce == 0,
5269                                     conf->device_lock);
5270                 atomic_inc(&conf->active_aligned_reads);
5271                 spin_unlock_irq(&conf->device_lock);
5272
5273                 if (mddev->gendisk)
5274                         trace_block_bio_remap(align_bi->bi_disk->queue,
5275                                               align_bi, disk_devt(mddev->gendisk),
5276                                               raid_bio->bi_iter.bi_sector);
5277                 generic_make_request(align_bi);
5278                 return 1;
5279         } else {
5280                 rcu_read_unlock();
5281                 bio_put(align_bi);
5282                 return 0;
5283         }
5284 }
5285
5286 static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
5287 {
5288         struct bio *split;
5289         sector_t sector = raid_bio->bi_iter.bi_sector;
5290         unsigned chunk_sects = mddev->chunk_sectors;
5291         unsigned sectors = chunk_sects - (sector & (chunk_sects-1));
5292
5293         if (sectors < bio_sectors(raid_bio)) {
5294                 struct r5conf *conf = mddev->private;
5295                 split = bio_split(raid_bio, sectors, GFP_NOIO, &conf->bio_split);
5296                 bio_chain(split, raid_bio);
5297                 generic_make_request(raid_bio);
5298                 raid_bio = split;
5299         }
5300
5301         if (!raid5_read_one_chunk(mddev, raid_bio))
5302                 return raid_bio;
5303
5304         return NULL;
5305 }
5306
5307 /* __get_priority_stripe - get the next stripe to process
5308  *
5309  * Full stripe writes are allowed to pass preread active stripes up until
5310  * the bypass_threshold is exceeded.  In general the bypass_count
5311  * increments when the handle_list is handled before the hold_list; however, it
5312  * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
5313  * stripe with in flight i/o.  The bypass_count will be reset when the
5314  * head of the hold_list has changed, i.e. the head was promoted to the
5315  * handle_list.
5316  */
5317 static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group)
5318 {
5319         struct stripe_head *sh, *tmp;
5320         struct list_head *handle_list = NULL;
5321         struct r5worker_group *wg;
5322         bool second_try = !r5c_is_writeback(conf->log) &&
5323                 !r5l_log_disk_error(conf);
5324         bool try_loprio = test_bit(R5C_LOG_TIGHT, &conf->cache_state) ||
5325                 r5l_log_disk_error(conf);
5326
5327 again:
5328         wg = NULL;
5329         sh = NULL;
5330         if (conf->worker_cnt_per_group == 0) {
5331                 handle_list = try_loprio ? &conf->loprio_list :
5332                                         &conf->handle_list;
5333         } else if (group != ANY_GROUP) {
5334                 handle_list = try_loprio ? &conf->worker_groups[group].loprio_list :
5335                                 &conf->worker_groups[group].handle_list;
5336                 wg = &conf->worker_groups[group];
5337         } else {
5338                 int i;
5339                 for (i = 0; i < conf->group_cnt; i++) {
5340                         handle_list = try_loprio ? &conf->worker_groups[i].loprio_list :
5341                                 &conf->worker_groups[i].handle_list;
5342                         wg = &conf->worker_groups[i];
5343                         if (!list_empty(handle_list))
5344                                 break;
5345                 }
5346         }
5347
5348         pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
5349                   __func__,
5350                   list_empty(handle_list) ? "empty" : "busy",
5351                   list_empty(&conf->hold_list) ? "empty" : "busy",
5352                   atomic_read(&conf->pending_full_writes), conf->bypass_count);
5353
5354         if (!list_empty(handle_list)) {
5355                 sh = list_entry(handle_list->next, typeof(*sh), lru);
5356
5357                 if (list_empty(&conf->hold_list))
5358                         conf->bypass_count = 0;
5359                 else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
5360                         if (conf->hold_list.next == conf->last_hold)
5361                                 conf->bypass_count++;
5362                         else {
5363                                 conf->last_hold = conf->hold_list.next;
5364                                 conf->bypass_count -= conf->bypass_threshold;
5365                                 if (conf->bypass_count < 0)
5366                                         conf->bypass_count = 0;
5367                         }
5368                 }
5369         } else if (!list_empty(&conf->hold_list) &&
5370                    ((conf->bypass_threshold &&
5371                      conf->bypass_count > conf->bypass_threshold) ||
5372                     atomic_read(&conf->pending_full_writes) == 0)) {
5373
5374                 list_for_each_entry(tmp, &conf->hold_list,  lru) {
5375                         if (conf->worker_cnt_per_group == 0 ||
5376                             group == ANY_GROUP ||
5377                             !cpu_online(tmp->cpu) ||
5378                             cpu_to_group(tmp->cpu) == group) {
5379                                 sh = tmp;
5380                                 break;
5381                         }
5382                 }
5383
5384                 if (sh) {
5385                         conf->bypass_count -= conf->bypass_threshold;
5386                         if (conf->bypass_count < 0)
5387                                 conf->bypass_count = 0;
5388                 }
5389                 wg = NULL;
5390         }
5391
5392         if (!sh) {
5393                 if (second_try)
5394                         return NULL;
5395                 second_try = true;
5396                 try_loprio = !try_loprio;
5397                 goto again;
5398         }
5399
5400         if (wg) {
5401                 wg->stripes_cnt--;
5402                 sh->group = NULL;
5403         }
5404         list_del_init(&sh->lru);
5405         BUG_ON(atomic_inc_return(&sh->count) != 1);
5406         return sh;
5407 }
5408
5409 struct raid5_plug_cb {
5410         struct blk_plug_cb      cb;
5411         struct list_head        list;
5412         struct list_head        temp_inactive_list[NR_STRIPE_HASH_LOCKS];
5413 };
5414
5415 static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
5416 {
5417         struct raid5_plug_cb *cb = container_of(
5418                 blk_cb, struct raid5_plug_cb, cb);
5419         struct stripe_head *sh;
5420         struct mddev *mddev = cb->cb.data;
5421         struct r5conf *conf = mddev->private;
5422         int cnt = 0;
5423         int hash;
5424
5425         if (cb->list.next && !list_empty(&cb->list)) {
5426                 spin_lock_irq(&conf->device_lock);
5427                 while (!list_empty(&cb->list)) {
5428                         sh = list_first_entry(&cb->list, struct stripe_head, lru);
5429                         list_del_init(&sh->lru);
5430                         /*
5431                          * avoid race release_stripe_plug() sees
5432                          * STRIPE_ON_UNPLUG_LIST clear but the stripe
5433                          * is still in our list
5434                          */
5435                         smp_mb__before_atomic();
5436                         clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
5437                         /*
5438                          * STRIPE_ON_RELEASE_LIST could be set here. In that
5439                          * case, the count is always > 1 here
5440                          */
5441                         hash = sh->hash_lock_index;
5442                         __release_stripe(conf, sh, &cb->temp_inactive_list[hash]);
5443                         cnt++;
5444                 }
5445                 spin_unlock_irq(&conf->device_lock);
5446         }
5447         release_inactive_stripe_list(conf, cb->temp_inactive_list,
5448                                      NR_STRIPE_HASH_LOCKS);
5449         if (mddev->queue)
5450                 trace_block_unplug(mddev->queue, cnt, !from_schedule);
5451         kfree(cb);
5452 }
5453
5454 static void release_stripe_plug(struct mddev *mddev,
5455                                 struct stripe_head *sh)
5456 {
5457         struct blk_plug_cb *blk_cb = blk_check_plugged(
5458                 raid5_unplug, mddev,
5459                 sizeof(struct raid5_plug_cb));
5460         struct raid5_plug_cb *cb;
5461
5462         if (!blk_cb) {
5463                 raid5_release_stripe(sh);
5464                 return;
5465         }
5466
5467         cb = container_of(blk_cb, struct raid5_plug_cb, cb);
5468
5469         if (cb->list.next == NULL) {
5470                 int i;
5471                 INIT_LIST_HEAD(&cb->list);
5472                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
5473                         INIT_LIST_HEAD(cb->temp_inactive_list + i);
5474         }
5475
5476         if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
5477                 list_add_tail(&sh->lru, &cb->list);
5478         else
5479                 raid5_release_stripe(sh);
5480 }
5481
5482 static void make_discard_request(struct mddev *mddev, struct bio *bi)
5483 {
5484         struct r5conf *conf = mddev->private;
5485         sector_t logical_sector, last_sector;
5486         struct stripe_head *sh;
5487         int stripe_sectors;
5488
5489         if (mddev->reshape_position != MaxSector)
5490                 /* Skip discard while reshape is happening */
5491                 return;
5492
5493         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
5494         last_sector = bi->bi_iter.bi_sector + (bi->bi_iter.bi_size>>9);
5495
5496         bi->bi_next = NULL;
5497
5498         stripe_sectors = conf->chunk_sectors *
5499                 (conf->raid_disks - conf->max_degraded);
5500         logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
5501                                                stripe_sectors);
5502         sector_div(last_sector, stripe_sectors);
5503
5504         logical_sector *= conf->chunk_sectors;
5505         last_sector *= conf->chunk_sectors;
5506
5507         for (; logical_sector < last_sector;
5508              logical_sector += STRIPE_SECTORS) {
5509                 DEFINE_WAIT(w);
5510                 int d;
5511         again:
5512                 sh = raid5_get_active_stripe(conf, logical_sector, 0, 0, 0);
5513                 prepare_to_wait(&conf->wait_for_overlap, &w,
5514                                 TASK_UNINTERRUPTIBLE);
5515                 set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5516                 if (test_bit(STRIPE_SYNCING, &sh->state)) {
5517                         raid5_release_stripe(sh);
5518                         schedule();
5519                         goto again;
5520                 }
5521                 clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5522                 spin_lock_irq(&sh->stripe_lock);
5523                 for (d = 0; d < conf->raid_disks; d++) {
5524                         if (d == sh->pd_idx || d == sh->qd_idx)
5525                                 continue;
5526                         if (sh->dev[d].towrite || sh->dev[d].toread) {
5527                                 set_bit(R5_Overlap, &sh->dev[d].flags);
5528                                 spin_unlock_irq(&sh->stripe_lock);
5529                                 raid5_release_stripe(sh);
5530                                 schedule();
5531                                 goto again;
5532                         }
5533                 }
5534                 set_bit(STRIPE_DISCARD, &sh->state);
5535                 finish_wait(&conf->wait_for_overlap, &w);
5536                 sh->overwrite_disks = 0;
5537                 for (d = 0; d < conf->raid_disks; d++) {
5538                         if (d == sh->pd_idx || d == sh->qd_idx)
5539                                 continue;
5540                         sh->dev[d].towrite = bi;
5541                         set_bit(R5_OVERWRITE, &sh->dev[d].flags);
5542                         bio_inc_remaining(bi);
5543                         md_write_inc(mddev, bi);
5544                         sh->overwrite_disks++;
5545                 }
5546                 spin_unlock_irq(&sh->stripe_lock);
5547                 if (conf->mddev->bitmap) {
5548                         for (d = 0;
5549                              d < conf->raid_disks - conf->max_degraded;
5550                              d++)
5551                                 md_bitmap_startwrite(mddev->bitmap,
5552                                                      sh->sector,
5553                                                      STRIPE_SECTORS,
5554                                                      0);
5555                         sh->bm_seq = conf->seq_flush + 1;
5556                         set_bit(STRIPE_BIT_DELAY, &sh->state);
5557                 }
5558
5559                 set_bit(STRIPE_HANDLE, &sh->state);
5560                 clear_bit(STRIPE_DELAYED, &sh->state);
5561                 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5562                         atomic_inc(&conf->preread_active_stripes);
5563                 release_stripe_plug(mddev, sh);
5564         }
5565
5566         bio_endio(bi);
5567 }
5568
5569 static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
5570 {
5571         struct r5conf *conf = mddev->private;
5572         int dd_idx;
5573         sector_t new_sector;
5574         sector_t logical_sector, last_sector;
5575         struct stripe_head *sh;
5576         const int rw = bio_data_dir(bi);
5577         DEFINE_WAIT(w);
5578         bool do_prepare;
5579         bool do_flush = false;
5580
5581         if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
5582                 int ret = log_handle_flush_request(conf, bi);
5583
5584                 if (ret == 0)
5585                         return true;
5586                 if (ret == -ENODEV) {
5587                         md_flush_request(mddev, bi);
5588                         return true;
5589                 }
5590                 /* ret == -EAGAIN, fallback */
5591                 /*
5592                  * if r5l_handle_flush_request() didn't clear REQ_PREFLUSH,
5593                  * we need to flush journal device
5594                  */
5595                 do_flush = bi->bi_opf & REQ_PREFLUSH;
5596         }
5597
5598         if (!md_write_start(mddev, bi))
5599                 return false;
5600         /*
5601          * If array is degraded, better not do chunk aligned read because
5602          * later we might have to read it again in order to reconstruct
5603          * data on failed drives.
5604          */
5605         if (rw == READ && mddev->degraded == 0 &&
5606             mddev->reshape_position == MaxSector) {
5607                 bi = chunk_aligned_read(mddev, bi);
5608                 if (!bi)
5609                         return true;
5610         }
5611
5612         if (unlikely(bio_op(bi) == REQ_OP_DISCARD)) {
5613                 make_discard_request(mddev, bi);
5614                 md_write_end(mddev);
5615                 return true;
5616         }
5617
5618         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
5619         last_sector = bio_end_sector(bi);
5620         bi->bi_next = NULL;
5621
5622         prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
5623         for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
5624                 int previous;
5625                 int seq;
5626
5627                 do_prepare = false;
5628         retry:
5629                 seq = read_seqcount_begin(&conf->gen_lock);
5630                 previous = 0;
5631                 if (do_prepare)
5632                         prepare_to_wait(&conf->wait_for_overlap, &w,
5633                                 TASK_UNINTERRUPTIBLE);
5634                 if (unlikely(conf->reshape_progress != MaxSector)) {
5635                         /* spinlock is needed as reshape_progress may be
5636                          * 64bit on a 32bit platform, and so it might be
5637                          * possible to see a half-updated value
5638                          * Of course reshape_progress could change after
5639                          * the lock is dropped, so once we get a reference
5640                          * to the stripe that we think it is, we will have
5641                          * to check again.
5642                          */
5643                         spin_lock_irq(&conf->device_lock);
5644                         if (mddev->reshape_backwards
5645                             ? logical_sector < conf->reshape_progress
5646                             : logical_sector >= conf->reshape_progress) {
5647                                 previous = 1;
5648                         } else {
5649                                 if (mddev->reshape_backwards
5650                                     ? logical_sector < conf->reshape_safe
5651                                     : logical_sector >= conf->reshape_safe) {
5652                                         spin_unlock_irq(&conf->device_lock);
5653                                         schedule();
5654                                         do_prepare = true;
5655                                         goto retry;
5656                                 }
5657                         }
5658                         spin_unlock_irq(&conf->device_lock);
5659                 }
5660
5661                 new_sector = raid5_compute_sector(conf, logical_sector,
5662                                                   previous,
5663                                                   &dd_idx, NULL);
5664                 pr_debug("raid456: raid5_make_request, sector %llu logical %llu\n",
5665                         (unsigned long long)new_sector,
5666                         (unsigned long long)logical_sector);
5667
5668                 sh = raid5_get_active_stripe(conf, new_sector, previous,
5669                                        (bi->bi_opf & REQ_RAHEAD), 0);
5670                 if (sh) {
5671                         if (unlikely(previous)) {
5672                                 /* expansion might have moved on while waiting for a
5673                                  * stripe, so we must do the range check again.
5674                                  * Expansion could still move past after this
5675                                  * test, but as we are holding a reference to
5676                                  * 'sh', we know that if that happens,
5677                                  *  STRIPE_EXPANDING will get set and the expansion
5678                                  * won't proceed until we finish with the stripe.
5679                                  */
5680                                 int must_retry = 0;
5681                                 spin_lock_irq(&conf->device_lock);
5682                                 if (mddev->reshape_backwards
5683                                     ? logical_sector >= conf->reshape_progress
5684                                     : logical_sector < conf->reshape_progress)
5685                                         /* mismatch, need to try again */
5686                                         must_retry = 1;
5687                                 spin_unlock_irq(&conf->device_lock);
5688                                 if (must_retry) {
5689                                         raid5_release_stripe(sh);
5690                                         schedule();
5691                                         do_prepare = true;
5692                                         goto retry;
5693                                 }
5694                         }
5695                         if (read_seqcount_retry(&conf->gen_lock, seq)) {
5696                                 /* Might have got the wrong stripe_head
5697                                  * by accident
5698                                  */
5699                                 raid5_release_stripe(sh);
5700                                 goto retry;
5701                         }
5702
5703                         if (test_bit(STRIPE_EXPANDING, &sh->state) ||
5704                             !add_stripe_bio(sh, bi, dd_idx, rw, previous)) {
5705                                 /* Stripe is busy expanding or
5706                                  * add failed due to overlap.  Flush everything
5707                                  * and wait a while
5708                                  */
5709                                 md_wakeup_thread(mddev->thread);
5710                                 raid5_release_stripe(sh);
5711                                 schedule();
5712                                 do_prepare = true;
5713                                 goto retry;
5714                         }
5715                         if (do_flush) {
5716                                 set_bit(STRIPE_R5C_PREFLUSH, &sh->state);
5717                                 /* we only need flush for one stripe */
5718                                 do_flush = false;
5719                         }
5720
5721                         set_bit(STRIPE_HANDLE, &sh->state);
5722                         clear_bit(STRIPE_DELAYED, &sh->state);
5723                         if ((!sh->batch_head || sh == sh->batch_head) &&
5724                             (bi->bi_opf & REQ_SYNC) &&
5725                             !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5726                                 atomic_inc(&conf->preread_active_stripes);
5727                         release_stripe_plug(mddev, sh);
5728                 } else {
5729                         /* cannot get stripe for read-ahead, just give-up */
5730                         bi->bi_status = BLK_STS_IOERR;
5731                         break;
5732                 }
5733         }
5734         finish_wait(&conf->wait_for_overlap, &w);
5735
5736         if (rw == WRITE)
5737                 md_write_end(mddev);
5738         bio_endio(bi);
5739         return true;
5740 }
5741
5742 static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
5743
5744 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
5745 {
5746         /* reshaping is quite different to recovery/resync so it is
5747          * handled quite separately ... here.
5748          *
5749          * On each call to sync_request, we gather one chunk worth of
5750          * destination stripes and flag them as expanding.
5751          * Then we find all the source stripes and request reads.
5752          * As the reads complete, handle_stripe will copy the data
5753          * into the destination stripe and release that stripe.
5754          */
5755         struct r5conf *conf = mddev->private;
5756         struct stripe_head *sh;
5757         struct md_rdev *rdev;
5758         sector_t first_sector, last_sector;
5759         int raid_disks = conf->previous_raid_disks;
5760         int data_disks = raid_disks - conf->max_degraded;
5761         int new_data_disks = conf->raid_disks - conf->max_degraded;
5762         int i;
5763         int dd_idx;
5764         sector_t writepos, readpos, safepos;
5765         sector_t stripe_addr;
5766         int reshape_sectors;
5767         struct list_head stripes;
5768         sector_t retn;
5769
5770         if (sector_nr == 0) {
5771                 /* If restarting in the middle, skip the initial sectors */
5772                 if (mddev->reshape_backwards &&
5773                     conf->reshape_progress < raid5_size(mddev, 0, 0)) {
5774                         sector_nr = raid5_size(mddev, 0, 0)
5775                                 - conf->reshape_progress;
5776                 } else if (mddev->reshape_backwards &&
5777                            conf->reshape_progress == MaxSector) {
5778                         /* shouldn't happen, but just in case, finish up.*/
5779                         sector_nr = MaxSector;
5780                 } else if (!mddev->reshape_backwards &&
5781                            conf->reshape_progress > 0)
5782                         sector_nr = conf->reshape_progress;
5783                 sector_div(sector_nr, new_data_disks);
5784                 if (sector_nr) {
5785                         mddev->curr_resync_completed = sector_nr;
5786                         sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5787                         *skipped = 1;
5788                         retn = sector_nr;
5789                         goto finish;
5790                 }
5791         }
5792
5793         /* We need to process a full chunk at a time.
5794          * If old and new chunk sizes differ, we need to process the
5795          * largest of these
5796          */
5797
5798         reshape_sectors = max(conf->chunk_sectors, conf->prev_chunk_sectors);
5799
5800         /* We update the metadata at least every 10 seconds, or when
5801          * the data about to be copied would over-write the source of
5802          * the data at the front of the range.  i.e. one new_stripe
5803          * along from reshape_progress new_maps to after where
5804          * reshape_safe old_maps to
5805          */
5806         writepos = conf->reshape_progress;
5807         sector_div(writepos, new_data_disks);
5808         readpos = conf->reshape_progress;
5809         sector_div(readpos, data_disks);
5810         safepos = conf->reshape_safe;
5811         sector_div(safepos, data_disks);
5812         if (mddev->reshape_backwards) {
5813                 BUG_ON(writepos < reshape_sectors);
5814                 writepos -= reshape_sectors;
5815                 readpos += reshape_sectors;
5816                 safepos += reshape_sectors;
5817         } else {
5818                 writepos += reshape_sectors;
5819                 /* readpos and safepos are worst-case calculations.
5820                  * A negative number is overly pessimistic, and causes
5821                  * obvious problems for unsigned storage.  So clip to 0.
5822                  */
5823                 readpos -= min_t(sector_t, reshape_sectors, readpos);
5824                 safepos -= min_t(sector_t, reshape_sectors, safepos);
5825         }
5826
5827         /* Having calculated the 'writepos' possibly use it
5828          * to set 'stripe_addr' which is where we will write to.
5829          */
5830         if (mddev->reshape_backwards) {
5831                 BUG_ON(conf->reshape_progress == 0);
5832                 stripe_addr = writepos;
5833                 BUG_ON((mddev->dev_sectors &
5834                         ~((sector_t)reshape_sectors - 1))
5835                        - reshape_sectors - stripe_addr
5836                        != sector_nr);
5837         } else {
5838                 BUG_ON(writepos != sector_nr + reshape_sectors);
5839                 stripe_addr = sector_nr;
5840         }
5841
5842         /* 'writepos' is the most advanced device address we might write.
5843          * 'readpos' is the least advanced device address we might read.
5844          * 'safepos' is the least address recorded in the metadata as having
5845          *     been reshaped.
5846          * If there is a min_offset_diff, these are adjusted either by
5847          * increasing the safepos/readpos if diff is negative, or
5848          * increasing writepos if diff is positive.
5849          * If 'readpos' is then behind 'writepos', there is no way that we can
5850          * ensure safety in the face of a crash - that must be done by userspace
5851          * making a backup of the data.  So in that case there is no particular
5852          * rush to update metadata.
5853          * Otherwise if 'safepos' is behind 'writepos', then we really need to
5854          * update the metadata to advance 'safepos' to match 'readpos' so that
5855          * we can be safe in the event of a crash.
5856          * So we insist on updating metadata if safepos is behind writepos and
5857          * readpos is beyond writepos.
5858          * In any case, update the metadata every 10 seconds.
5859          * Maybe that number should be configurable, but I'm not sure it is
5860          * worth it.... maybe it could be a multiple of safemode_delay???
5861          */
5862         if (conf->min_offset_diff < 0) {
5863                 safepos += -conf->min_offset_diff;
5864                 readpos += -conf->min_offset_diff;
5865         } else
5866                 writepos += conf->min_offset_diff;
5867
5868         if ((mddev->reshape_backwards
5869              ? (safepos > writepos && readpos < writepos)
5870              : (safepos < writepos && readpos > writepos)) ||
5871             time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
5872                 /* Cannot proceed until we've updated the superblock... */
5873                 wait_event(conf->wait_for_overlap,
5874                            atomic_read(&conf->reshape_stripes)==0
5875                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5876                 if (atomic_read(&conf->reshape_stripes) != 0)
5877                         return 0;
5878                 mddev->reshape_position = conf->reshape_progress;
5879                 mddev->curr_resync_completed = sector_nr;
5880                 if (!mddev->reshape_backwards)
5881                         /* Can update recovery_offset */
5882                         rdev_for_each(rdev, mddev)
5883                                 if (rdev->raid_disk >= 0 &&
5884                                     !test_bit(Journal, &rdev->flags) &&
5885                                     !test_bit(In_sync, &rdev->flags) &&
5886                                     rdev->recovery_offset < sector_nr)
5887                                         rdev->recovery_offset = sector_nr;
5888
5889                 conf->reshape_checkpoint = jiffies;
5890                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
5891                 md_wakeup_thread(mddev->thread);
5892                 wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
5893                            test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5894                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5895                         return 0;
5896                 spin_lock_irq(&conf->device_lock);
5897                 conf->reshape_safe = mddev->reshape_position;
5898                 spin_unlock_irq(&conf->device_lock);
5899                 wake_up(&conf->wait_for_overlap);
5900                 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5901         }
5902
5903         INIT_LIST_HEAD(&stripes);
5904         for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
5905                 int j;
5906                 int skipped_disk = 0;
5907                 sh = raid5_get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
5908                 set_bit(STRIPE_EXPANDING, &sh->state);
5909                 atomic_inc(&conf->reshape_stripes);
5910                 /* If any of this stripe is beyond the end of the old
5911                  * array, then we need to zero those blocks
5912                  */
5913                 for (j=sh->disks; j--;) {
5914                         sector_t s;
5915                         if (j == sh->pd_idx)
5916                                 continue;
5917                         if (conf->level == 6 &&
5918                             j == sh->qd_idx)
5919                                 continue;
5920                         s = raid5_compute_blocknr(sh, j, 0);
5921                         if (s < raid5_size(mddev, 0, 0)) {
5922                                 skipped_disk = 1;
5923                                 continue;
5924                         }
5925                         memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE);
5926                         set_bit(R5_Expanded, &sh->dev[j].flags);
5927                         set_bit(R5_UPTODATE, &sh->dev[j].flags);
5928                 }
5929                 if (!skipped_disk) {
5930                         set_bit(STRIPE_EXPAND_READY, &sh->state);
5931                         set_bit(STRIPE_HANDLE, &sh->state);
5932                 }
5933                 list_add(&sh->lru, &stripes);
5934         }
5935         spin_lock_irq(&conf->device_lock);
5936         if (mddev->reshape_backwards)
5937                 conf->reshape_progress -= reshape_sectors * new_data_disks;
5938         else
5939                 conf->reshape_progress += reshape_sectors * new_data_disks;
5940         spin_unlock_irq(&conf->device_lock);
5941         /* Ok, those stripe are ready. We can start scheduling
5942          * reads on the source stripes.
5943          * The source stripes are determined by mapping the first and last
5944          * block on the destination stripes.
5945          */
5946         first_sector =
5947                 raid5_compute_sector(conf, stripe_addr*(new_data_disks),
5948                                      1, &dd_idx, NULL);
5949         last_sector =
5950                 raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
5951                                             * new_data_disks - 1),
5952                                      1, &dd_idx, NULL);
5953         if (last_sector >= mddev->dev_sectors)
5954                 last_sector = mddev->dev_sectors - 1;
5955         while (first_sector <= last_sector) {
5956                 sh = raid5_get_active_stripe(conf, first_sector, 1, 0, 1);
5957                 set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
5958                 set_bit(STRIPE_HANDLE, &sh->state);
5959                 raid5_release_stripe(sh);
5960                 first_sector += STRIPE_SECTORS;
5961         }
5962         /* Now that the sources are clearly marked, we can release
5963          * the destination stripes
5964          */
5965         while (!list_empty(&stripes)) {
5966                 sh = list_entry(stripes.next, struct stripe_head, lru);
5967                 list_del_init(&sh->lru);
5968                 raid5_release_stripe(sh);
5969         }
5970         /* If this takes us to the resync_max point where we have to pause,
5971          * then we need to write out the superblock.
5972          */
5973         sector_nr += reshape_sectors;
5974         retn = reshape_sectors;
5975 finish:
5976         if (mddev->curr_resync_completed > mddev->resync_max ||
5977             (sector_nr - mddev->curr_resync_completed) * 2
5978             >= mddev->resync_max - mddev->curr_resync_completed) {
5979                 /* Cannot proceed until we've updated the superblock... */
5980                 wait_event(conf->wait_for_overlap,
5981                            atomic_read(&conf->reshape_stripes) == 0
5982                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5983                 if (atomic_read(&conf->reshape_stripes) != 0)
5984                         goto ret;
5985                 mddev->reshape_position = conf->reshape_progress;
5986                 mddev->curr_resync_completed = sector_nr;
5987                 if (!mddev->reshape_backwards)
5988                         /* Can update recovery_offset */
5989                         rdev_for_each(rdev, mddev)
5990                                 if (rdev->raid_disk >= 0 &&
5991                                     !test_bit(Journal, &rdev->flags) &&
5992                                     !test_bit(In_sync, &rdev->flags) &&
5993                                     rdev->recovery_offset < sector_nr)
5994                                         rdev->recovery_offset = sector_nr;
5995                 conf->reshape_checkpoint = jiffies;
5996                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
5997                 md_wakeup_thread(mddev->thread);
5998                 wait_event(mddev->sb_wait,
5999                            !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)
6000                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6001                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6002                         goto ret;
6003                 spin_lock_irq(&conf->device_lock);
6004                 conf->reshape_safe = mddev->reshape_position;
6005                 spin_unlock_irq(&conf->device_lock);
6006                 wake_up(&conf->wait_for_overlap);
6007                 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
6008         }
6009 ret:
6010         return retn;
6011 }
6012
6013 static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_nr,
6014                                           int *skipped)
6015 {
6016         struct r5conf *conf = mddev->private;
6017         struct stripe_head *sh;
6018         sector_t max_sector = mddev->dev_sectors;
6019         sector_t sync_blocks;
6020         int still_degraded = 0;
6021         int i;
6022
6023         if (sector_nr >= max_sector) {
6024                 /* just being told to finish up .. nothing much to do */
6025
6026                 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
6027                         end_reshape(conf);
6028                         return 0;
6029                 }
6030
6031                 if (mddev->curr_resync < max_sector) /* aborted */
6032                         md_bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
6033                                            &sync_blocks, 1);
6034                 else /* completed sync */
6035                         conf->fullsync = 0;
6036                 md_bitmap_close_sync(mddev->bitmap);
6037
6038                 return 0;
6039         }
6040
6041         /* Allow raid5_quiesce to complete */
6042         wait_event(conf->wait_for_overlap, conf->quiesce != 2);
6043
6044         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6045                 return reshape_request(mddev, sector_nr, skipped);
6046
6047         /* No need to check resync_max as we never do more than one
6048          * stripe, and as resync_max will always be on a chunk boundary,
6049          * if the check in md_do_sync didn't fire, there is no chance
6050          * of overstepping resync_max here
6051          */
6052
6053         /* if there is too many failed drives and we are trying
6054          * to resync, then assert that we are finished, because there is
6055          * nothing we can do.
6056          */
6057         if (mddev->degraded >= conf->max_degraded &&
6058             test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
6059                 sector_t rv = mddev->dev_sectors - sector_nr;
6060                 *skipped = 1;
6061                 return rv;
6062         }
6063         if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
6064             !conf->fullsync &&
6065             !md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
6066             sync_blocks >= STRIPE_SECTORS) {
6067                 /* we can skip this block, and probably more */
6068                 sync_blocks /= STRIPE_SECTORS;
6069                 *skipped = 1;
6070                 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
6071         }
6072
6073         md_bitmap_cond_end_sync(mddev->bitmap, sector_nr, false);
6074
6075         sh = raid5_get_active_stripe(conf, sector_nr, 0, 1, 0);
6076         if (sh == NULL) {
6077                 sh = raid5_get_active_stripe(conf, sector_nr, 0, 0, 0);
6078                 /* make sure we don't swamp the stripe cache if someone else
6079                  * is trying to get access
6080                  */
6081                 schedule_timeout_uninterruptible(1);
6082         }
6083         /* Need to check if array will still be degraded after recovery/resync
6084          * Note in case of > 1 drive failures it's possible we're rebuilding
6085          * one drive while leaving another faulty drive in array.
6086          */
6087         rcu_read_lock();
6088         for (i = 0; i < conf->raid_disks; i++) {
6089                 struct md_rdev *rdev = READ_ONCE(conf->disks[i].rdev);
6090
6091                 if (rdev == NULL || test_bit(Faulty, &rdev->flags))
6092                         still_degraded = 1;
6093         }
6094         rcu_read_unlock();
6095
6096         md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
6097
6098         set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
6099         set_bit(STRIPE_HANDLE, &sh->state);
6100
6101         raid5_release_stripe(sh);
6102
6103         return STRIPE_SECTORS;
6104 }
6105
6106 static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio,
6107                                unsigned int offset)
6108 {
6109         /* We may not be able to submit a whole bio at once as there
6110          * may not be enough stripe_heads available.
6111          * We cannot pre-allocate enough stripe_heads as we may need
6112          * more than exist in the cache (if we allow ever large chunks).
6113          * So we do one stripe head at a time and record in
6114          * ->bi_hw_segments how many have been done.
6115          *
6116          * We *know* that this entire raid_bio is in one chunk, so
6117          * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
6118          */
6119         struct stripe_head *sh;
6120         int dd_idx;
6121         sector_t sector, logical_sector, last_sector;
6122         int scnt = 0;
6123         int handled = 0;
6124
6125         logical_sector = raid_bio->bi_iter.bi_sector &
6126                 ~((sector_t)STRIPE_SECTORS-1);
6127         sector = raid5_compute_sector(conf, logical_sector,
6128                                       0, &dd_idx, NULL);
6129         last_sector = bio_end_sector(raid_bio);
6130
6131         for (; logical_sector < last_sector;
6132              logical_sector += STRIPE_SECTORS,
6133                      sector += STRIPE_SECTORS,
6134                      scnt++) {
6135
6136                 if (scnt < offset)
6137                         /* already done this stripe */
6138                         continue;
6139
6140                 sh = raid5_get_active_stripe(conf, sector, 0, 1, 1);
6141
6142                 if (!sh) {
6143                         /* failed to get a stripe - must wait */
6144                         conf->retry_read_aligned = raid_bio;
6145                         conf->retry_read_offset = scnt;
6146                         return handled;
6147                 }
6148
6149                 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0, 0)) {
6150                         raid5_release_stripe(sh);
6151                         conf->retry_read_aligned = raid_bio;
6152                         conf->retry_read_offset = scnt;
6153                         return handled;
6154                 }
6155
6156                 set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
6157                 handle_stripe(sh);
6158                 raid5_release_stripe(sh);
6159                 handled++;
6160         }
6161
6162         bio_endio(raid_bio);
6163
6164         if (atomic_dec_and_test(&conf->active_aligned_reads))
6165                 wake_up(&conf->wait_for_quiescent);
6166         return handled;
6167 }
6168
6169 static int handle_active_stripes(struct r5conf *conf, int group,
6170                                  struct r5worker *worker,
6171                                  struct list_head *temp_inactive_list)
6172                 __releases(&conf->device_lock)
6173                 __acquires(&conf->device_lock)
6174 {
6175         struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
6176         int i, batch_size = 0, hash;
6177         bool release_inactive = false;
6178
6179         while (batch_size < MAX_STRIPE_BATCH &&
6180                         (sh = __get_priority_stripe(conf, group)) != NULL)
6181                 batch[batch_size++] = sh;
6182
6183         if (batch_size == 0) {
6184                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6185                         if (!list_empty(temp_inactive_list + i))
6186                                 break;
6187                 if (i == NR_STRIPE_HASH_LOCKS) {
6188                         spin_unlock_irq(&conf->device_lock);
6189                         log_flush_stripe_to_raid(conf);
6190                         spin_lock_irq(&conf->device_lock);
6191                         return batch_size;
6192                 }
6193                 release_inactive = true;
6194         }
6195         spin_unlock_irq(&conf->device_lock);
6196
6197         release_inactive_stripe_list(conf, temp_inactive_list,
6198                                      NR_STRIPE_HASH_LOCKS);
6199
6200         r5l_flush_stripe_to_raid(conf->log);
6201         if (release_inactive) {
6202                 spin_lock_irq(&conf->device_lock);
6203                 return 0;
6204         }
6205
6206         for (i = 0; i < batch_size; i++)
6207                 handle_stripe(batch[i]);
6208         log_write_stripe_run(conf);
6209
6210         cond_resched();
6211
6212         spin_lock_irq(&conf->device_lock);
6213         for (i = 0; i < batch_size; i++) {
6214                 hash = batch[i]->hash_lock_index;
6215                 __release_stripe(conf, batch[i], &temp_inactive_list[hash]);
6216         }
6217         return batch_size;
6218 }
6219
6220 static void raid5_do_work(struct work_struct *work)
6221 {
6222         struct r5worker *worker = container_of(work, struct r5worker, work);
6223         struct r5worker_group *group = worker->group;
6224         struct r5conf *conf = group->conf;
6225         struct mddev *mddev = conf->mddev;
6226         int group_id = group - conf->worker_groups;
6227         int handled;
6228         struct blk_plug plug;
6229
6230         pr_debug("+++ raid5worker active\n");
6231
6232         blk_start_plug(&plug);
6233         handled = 0;
6234         spin_lock_irq(&conf->device_lock);
6235         while (1) {
6236                 int batch_size, released;
6237
6238                 released = release_stripe_list(conf, worker->temp_inactive_list);
6239
6240                 batch_size = handle_active_stripes(conf, group_id, worker,
6241                                                    worker->temp_inactive_list);
6242                 worker->working = false;
6243                 if (!batch_size && !released)
6244                         break;
6245                 handled += batch_size;
6246                 wait_event_lock_irq(mddev->sb_wait,
6247                         !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
6248                         conf->device_lock);
6249         }
6250         pr_debug("%d stripes handled\n", handled);
6251
6252         spin_unlock_irq(&conf->device_lock);
6253
6254         flush_deferred_bios(conf);
6255
6256         r5l_flush_stripe_to_raid(conf->log);
6257
6258         async_tx_issue_pending_all();
6259         blk_finish_plug(&plug);
6260
6261         pr_debug("--- raid5worker inactive\n");
6262 }
6263
6264 /*
6265  * This is our raid5 kernel thread.
6266  *
6267  * We scan the hash table for stripes which can be handled now.
6268  * During the scan, completed stripes are saved for us by the interrupt
6269  * handler, so that they will not have to wait for our next wakeup.
6270  */
6271 static void raid5d(struct md_thread *thread)
6272 {
6273         struct mddev *mddev = thread->mddev;
6274         struct r5conf *conf = mddev->private;
6275         int handled;
6276         struct blk_plug plug;
6277
6278         pr_debug("+++ raid5d active\n");
6279
6280         md_check_recovery(mddev);
6281
6282         blk_start_plug(&plug);
6283         handled = 0;
6284         spin_lock_irq(&conf->device_lock);
6285         while (1) {
6286                 struct bio *bio;
6287                 int batch_size, released;
6288                 unsigned int offset;
6289
6290                 released = release_stripe_list(conf, conf->temp_inactive_list);
6291                 if (released)
6292                         clear_bit(R5_DID_ALLOC, &conf->cache_state);
6293
6294                 if (
6295                     !list_empty(&conf->bitmap_list)) {
6296                         /* Now is a good time to flush some bitmap updates */
6297                         conf->seq_flush++;
6298                         spin_unlock_irq(&conf->device_lock);
6299                         md_bitmap_unplug(mddev->bitmap);
6300                         spin_lock_irq(&conf->device_lock);
6301                         conf->seq_write = conf->seq_flush;
6302                         activate_bit_delay(conf, conf->temp_inactive_list);
6303                 }
6304                 raid5_activate_delayed(conf);
6305
6306                 while ((bio = remove_bio_from_retry(conf, &offset))) {
6307                         int ok;
6308                         spin_unlock_irq(&conf->device_lock);
6309                         ok = retry_aligned_read(conf, bio, offset);
6310                         spin_lock_irq(&conf->device_lock);
6311                         if (!ok)
6312                                 break;
6313                         handled++;
6314                 }
6315
6316                 batch_size = handle_active_stripes(conf, ANY_GROUP, NULL,
6317                                                    conf->temp_inactive_list);
6318                 if (!batch_size && !released)
6319                         break;
6320                 handled += batch_size;
6321
6322                 if (mddev->sb_flags & ~(1 << MD_SB_CHANGE_PENDING)) {
6323                         spin_unlock_irq(&conf->device_lock);
6324                         md_check_recovery(mddev);
6325                         spin_lock_irq(&conf->device_lock);
6326                 }
6327         }
6328         pr_debug("%d stripes handled\n", handled);
6329
6330         spin_unlock_irq(&conf->device_lock);
6331         if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state) &&
6332             mutex_trylock(&conf->cache_size_mutex)) {
6333                 grow_one_stripe(conf, __GFP_NOWARN);
6334                 /* Set flag even if allocation failed.  This helps
6335                  * slow down allocation requests when mem is short
6336                  */
6337                 set_bit(R5_DID_ALLOC, &conf->cache_state);
6338                 mutex_unlock(&conf->cache_size_mutex);
6339         }
6340
6341         flush_deferred_bios(conf);
6342
6343         r5l_flush_stripe_to_raid(conf->log);
6344
6345         async_tx_issue_pending_all();
6346         blk_finish_plug(&plug);
6347
6348         pr_debug("--- raid5d inactive\n");
6349 }
6350
6351 static ssize_t
6352 raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
6353 {
6354         struct r5conf *conf;
6355         int ret = 0;
6356         spin_lock(&mddev->lock);
6357         conf = mddev->private;
6358         if (conf)
6359                 ret = sprintf(page, "%d\n", conf->min_nr_stripes);
6360         spin_unlock(&mddev->lock);
6361         return ret;
6362 }
6363
6364 int
6365 raid5_set_cache_size(struct mddev *mddev, int size)
6366 {
6367         int result = 0;
6368         struct r5conf *conf = mddev->private;
6369
6370         if (size <= 16 || size > 32768)
6371                 return -EINVAL;
6372
6373         conf->min_nr_stripes = size;
6374         mutex_lock(&conf->cache_size_mutex);
6375         while (size < conf->max_nr_stripes &&
6376                drop_one_stripe(conf))
6377                 ;
6378         mutex_unlock(&conf->cache_size_mutex);
6379
6380         md_allow_write(mddev);
6381
6382         mutex_lock(&conf->cache_size_mutex);
6383         while (size > conf->max_nr_stripes)
6384                 if (!grow_one_stripe(conf, GFP_KERNEL)) {
6385                         conf->min_nr_stripes = conf->max_nr_stripes;
6386                         result = -ENOMEM;
6387                         break;
6388                 }
6389         mutex_unlock(&conf->cache_size_mutex);
6390
6391         return result;
6392 }
6393 EXPORT_SYMBOL(raid5_set_cache_size);
6394
6395 static ssize_t
6396 raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
6397 {
6398         struct r5conf *conf;
6399         unsigned long new;
6400         int err;
6401
6402         if (len >= PAGE_SIZE)
6403                 return -EINVAL;
6404         if (kstrtoul(page, 10, &new))
6405                 return -EINVAL;
6406         err = mddev_lock(mddev);
6407         if (err)
6408                 return err;
6409         conf = mddev->private;
6410         if (!conf)
6411                 err = -ENODEV;
6412         else
6413                 err = raid5_set_cache_size(mddev, new);
6414         mddev_unlock(mddev);
6415
6416         return err ?: len;
6417 }
6418
6419 static struct md_sysfs_entry
6420 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
6421                                 raid5_show_stripe_cache_size,
6422                                 raid5_store_stripe_cache_size);
6423
6424 static ssize_t
6425 raid5_show_rmw_level(struct mddev  *mddev, char *page)
6426 {
6427         struct r5conf *conf = mddev->private;
6428         if (conf)
6429                 return sprintf(page, "%d\n", conf->rmw_level);
6430         else
6431                 return 0;
6432 }
6433
6434 static ssize_t
6435 raid5_store_rmw_level(struct mddev  *mddev, const char *page, size_t len)
6436 {
6437         struct r5conf *conf = mddev->private;
6438         unsigned long new;
6439
6440         if (!conf)
6441                 return -ENODEV;
6442
6443         if (len >= PAGE_SIZE)
6444                 return -EINVAL;
6445
6446         if (kstrtoul(page, 10, &new))
6447                 return -EINVAL;
6448
6449         if (new != PARITY_DISABLE_RMW && !raid6_call.xor_syndrome)
6450                 return -EINVAL;
6451
6452         if (new != PARITY_DISABLE_RMW &&
6453             new != PARITY_ENABLE_RMW &&
6454             new != PARITY_PREFER_RMW)
6455                 return -EINVAL;
6456
6457         conf->rmw_level = new;
6458         return len;
6459 }
6460
6461 static struct md_sysfs_entry
6462 raid5_rmw_level = __ATTR(rmw_level, S_IRUGO | S_IWUSR,
6463                          raid5_show_rmw_level,
6464                          raid5_store_rmw_level);
6465
6466
6467 static ssize_t
6468 raid5_show_preread_threshold(struct mddev *mddev, char *page)
6469 {
6470         struct r5conf *conf;
6471         int ret = 0;
6472         spin_lock(&mddev->lock);
6473         conf = mddev->private;
6474         if (conf)
6475                 ret = sprintf(page, "%d\n", conf->bypass_threshold);
6476         spin_unlock(&mddev->lock);
6477         return ret;
6478 }
6479
6480 static ssize_t
6481 raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
6482 {
6483         struct r5conf *conf;
6484         unsigned long new;
6485         int err;
6486
6487         if (len >= PAGE_SIZE)
6488                 return -EINVAL;
6489         if (kstrtoul(page, 10, &new))
6490                 return -EINVAL;
6491
6492         err = mddev_lock(mddev);
6493         if (err)
6494                 return err;
6495         conf = mddev->private;
6496         if (!conf)
6497                 err = -ENODEV;
6498         else if (new > conf->min_nr_stripes)
6499                 err = -EINVAL;
6500         else
6501                 conf->bypass_threshold = new;
6502         mddev_unlock(mddev);
6503         return err ?: len;
6504 }
6505
6506 static struct md_sysfs_entry
6507 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
6508                                         S_IRUGO | S_IWUSR,
6509                                         raid5_show_preread_threshold,
6510                                         raid5_store_preread_threshold);
6511
6512 static ssize_t
6513 raid5_show_skip_copy(struct mddev *mddev, char *page)
6514 {
6515         struct r5conf *conf;
6516         int ret = 0;
6517         spin_lock(&mddev->lock);
6518         conf = mddev->private;
6519         if (conf)
6520                 ret = sprintf(page, "%d\n", conf->skip_copy);
6521         spin_unlock(&mddev->lock);
6522         return ret;
6523 }
6524
6525 static ssize_t
6526 raid5_store_skip_copy(struct mddev *mddev, const char *page, size_t len)
6527 {
6528         struct r5conf *conf;
6529         unsigned long new;
6530         int err;
6531
6532         if (len >= PAGE_SIZE)
6533                 return -EINVAL;
6534         if (kstrtoul(page, 10, &new))
6535                 return -EINVAL;
6536         new = !!new;
6537
6538         err = mddev_lock(mddev);
6539         if (err)
6540                 return err;
6541         conf = mddev->private;
6542         if (!conf)
6543                 err = -ENODEV;
6544         else if (new != conf->skip_copy) {
6545                 mddev_suspend(mddev);
6546                 conf->skip_copy = new;
6547                 if (new)
6548                         mddev->queue->backing_dev_info->capabilities |=
6549                                 BDI_CAP_STABLE_WRITES;
6550                 else
6551                         mddev->queue->backing_dev_info->capabilities &=
6552                                 ~BDI_CAP_STABLE_WRITES;
6553                 mddev_resume(mddev);
6554         }
6555         mddev_unlock(mddev);
6556         return err ?: len;
6557 }
6558
6559 static struct md_sysfs_entry
6560 raid5_skip_copy = __ATTR(skip_copy, S_IRUGO | S_IWUSR,
6561                                         raid5_show_skip_copy,
6562                                         raid5_store_skip_copy);
6563
6564 static ssize_t
6565 stripe_cache_active_show(struct mddev *mddev, char *page)
6566 {
6567         struct r5conf *conf = mddev->private;
6568         if (conf)
6569                 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
6570         else
6571                 return 0;
6572 }
6573
6574 static struct md_sysfs_entry
6575 raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
6576
6577 static ssize_t
6578 raid5_show_group_thread_cnt(struct mddev *mddev, char *page)
6579 {
6580         struct r5conf *conf;
6581         int ret = 0;
6582         spin_lock(&mddev->lock);
6583         conf = mddev->private;
6584         if (conf)
6585                 ret = sprintf(page, "%d\n", conf->worker_cnt_per_group);
6586         spin_unlock(&mddev->lock);
6587         return ret;
6588 }
6589
6590 static int alloc_thread_groups(struct r5conf *conf, int cnt,
6591                                int *group_cnt,
6592                                int *worker_cnt_per_group,
6593                                struct r5worker_group **worker_groups);
6594 static ssize_t
6595 raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
6596 {
6597         struct r5conf *conf;
6598         unsigned int new;
6599         int err;
6600         struct r5worker_group *new_groups, *old_groups;
6601         int group_cnt, worker_cnt_per_group;
6602
6603         if (len >= PAGE_SIZE)
6604                 return -EINVAL;
6605         if (kstrtouint(page, 10, &new))
6606                 return -EINVAL;
6607         /* 8192 should be big enough */
6608         if (new > 8192)
6609                 return -EINVAL;
6610
6611         err = mddev_lock(mddev);
6612         if (err)
6613                 return err;
6614         conf = mddev->private;
6615         if (!conf)
6616                 err = -ENODEV;
6617         else if (new != conf->worker_cnt_per_group) {
6618                 mddev_suspend(mddev);
6619
6620                 old_groups = conf->worker_groups;
6621                 if (old_groups)
6622                         flush_workqueue(raid5_wq);
6623
6624                 err = alloc_thread_groups(conf, new,
6625                                           &group_cnt, &worker_cnt_per_group,
6626                                           &new_groups);
6627                 if (!err) {
6628                         spin_lock_irq(&conf->device_lock);
6629                         conf->group_cnt = group_cnt;
6630                         conf->worker_cnt_per_group = worker_cnt_per_group;
6631                         conf->worker_groups = new_groups;
6632                         spin_unlock_irq(&conf->device_lock);
6633
6634                         if (old_groups)
6635                                 kfree(old_groups[0].workers);
6636                         kfree(old_groups);
6637                 }
6638                 mddev_resume(mddev);
6639         }
6640         mddev_unlock(mddev);
6641
6642         return err ?: len;
6643 }
6644
6645 static struct md_sysfs_entry
6646 raid5_group_thread_cnt = __ATTR(group_thread_cnt, S_IRUGO | S_IWUSR,
6647                                 raid5_show_group_thread_cnt,
6648                                 raid5_store_group_thread_cnt);
6649
6650 static struct attribute *raid5_attrs[] =  {
6651         &raid5_stripecache_size.attr,
6652         &raid5_stripecache_active.attr,
6653         &raid5_preread_bypass_threshold.attr,
6654         &raid5_group_thread_cnt.attr,
6655         &raid5_skip_copy.attr,
6656         &raid5_rmw_level.attr,
6657         &r5c_journal_mode.attr,
6658         &ppl_write_hint.attr,
6659         NULL,
6660 };
6661 static struct attribute_group raid5_attrs_group = {
6662         .name = NULL,
6663         .attrs = raid5_attrs,
6664 };
6665
6666 static int alloc_thread_groups(struct r5conf *conf, int cnt,
6667                                int *group_cnt,
6668                                int *worker_cnt_per_group,
6669                                struct r5worker_group **worker_groups)
6670 {
6671         int i, j, k;
6672         ssize_t size;
6673         struct r5worker *workers;
6674
6675         *worker_cnt_per_group = cnt;
6676         if (cnt == 0) {
6677                 *group_cnt = 0;
6678                 *worker_groups = NULL;
6679                 return 0;
6680         }
6681         *group_cnt = num_possible_nodes();
6682         size = sizeof(struct r5worker) * cnt;
6683         workers = kcalloc(size, *group_cnt, GFP_NOIO);
6684         *worker_groups = kcalloc(*group_cnt, sizeof(struct r5worker_group),
6685                                  GFP_NOIO);
6686         if (!*worker_groups || !workers) {
6687                 kfree(workers);
6688                 kfree(*worker_groups);
6689                 return -ENOMEM;
6690         }
6691
6692         for (i = 0; i < *group_cnt; i++) {
6693                 struct r5worker_group *group;
6694
6695                 group = &(*worker_groups)[i];
6696                 INIT_LIST_HEAD(&group->handle_list);
6697                 INIT_LIST_HEAD(&group->loprio_list);
6698                 group->conf = conf;
6699                 group->workers = workers + i * cnt;
6700
6701                 for (j = 0; j < cnt; j++) {
6702                         struct r5worker *worker = group->workers + j;
6703                         worker->group = group;
6704                         INIT_WORK(&worker->work, raid5_do_work);
6705
6706                         for (k = 0; k < NR_STRIPE_HASH_LOCKS; k++)
6707                                 INIT_LIST_HEAD(worker->temp_inactive_list + k);
6708                 }
6709         }
6710
6711         return 0;
6712 }
6713
6714 static void free_thread_groups(struct r5conf *conf)
6715 {
6716         if (conf->worker_groups)
6717                 kfree(conf->worker_groups[0].workers);
6718         kfree(conf->worker_groups);
6719         conf->worker_groups = NULL;
6720 }
6721
6722 static sector_t
6723 raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
6724 {
6725         struct r5conf *conf = mddev->private;
6726
6727         if (!sectors)
6728                 sectors = mddev->dev_sectors;
6729         if (!raid_disks)
6730                 /* size is defined by the smallest of previous and new size */
6731                 raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
6732
6733         sectors &= ~((sector_t)conf->chunk_sectors - 1);
6734         sectors &= ~((sector_t)conf->prev_chunk_sectors - 1);
6735         return sectors * (raid_disks - conf->max_degraded);
6736 }
6737
6738 static void free_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6739 {
6740         safe_put_page(percpu->spare_page);
6741         percpu->spare_page = NULL;
6742         kvfree(percpu->scribble);
6743         percpu->scribble = NULL;
6744 }
6745
6746 static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6747 {
6748         if (conf->level == 6 && !percpu->spare_page) {
6749                 percpu->spare_page = alloc_page(GFP_KERNEL);
6750                 if (!percpu->spare_page)
6751                         return -ENOMEM;
6752         }
6753
6754         if (scribble_alloc(percpu,
6755                            max(conf->raid_disks,
6756                                conf->previous_raid_disks),
6757                            max(conf->chunk_sectors,
6758                                conf->prev_chunk_sectors)
6759                            / STRIPE_SECTORS,
6760                            GFP_KERNEL)) {
6761                 free_scratch_buffer(conf, percpu);
6762                 return -ENOMEM;
6763         }
6764
6765         return 0;
6766 }
6767
6768 static int raid456_cpu_dead(unsigned int cpu, struct hlist_node *node)
6769 {
6770         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
6771
6772         free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));
6773         return 0;
6774 }
6775
6776 static void raid5_free_percpu(struct r5conf *conf)
6777 {
6778         if (!conf->percpu)
6779                 return;
6780
6781         cpuhp_state_remove_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
6782         free_percpu(conf->percpu);
6783 }
6784
6785 static void free_conf(struct r5conf *conf)
6786 {
6787         int i;
6788
6789         log_exit(conf);
6790
6791         unregister_shrinker(&conf->shrinker);
6792         free_thread_groups(conf);
6793         shrink_stripes(conf);
6794         raid5_free_percpu(conf);
6795         for (i = 0; i < conf->pool_size; i++)
6796                 if (conf->disks[i].extra_page)
6797                         put_page(conf->disks[i].extra_page);
6798         kfree(conf->disks);
6799         bioset_exit(&conf->bio_split);
6800         kfree(conf->stripe_hashtbl);
6801         kfree(conf->pending_data);
6802         kfree(conf);
6803 }
6804
6805 static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
6806 {
6807         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
6808         struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);
6809
6810         if (alloc_scratch_buffer(conf, percpu)) {
6811                 pr_warn("%s: failed memory allocation for cpu%u\n",
6812                         __func__, cpu);
6813                 return -ENOMEM;
6814         }
6815         return 0;
6816 }
6817
6818 static int raid5_alloc_percpu(struct r5conf *conf)
6819 {
6820         int err = 0;
6821
6822         conf->percpu = alloc_percpu(struct raid5_percpu);
6823         if (!conf->percpu)
6824                 return -ENOMEM;
6825
6826         err = cpuhp_state_add_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
6827         if (!err) {
6828                 conf->scribble_disks = max(conf->raid_disks,
6829                         conf->previous_raid_disks);
6830                 conf->scribble_sectors = max(conf->chunk_sectors,
6831                         conf->prev_chunk_sectors);
6832         }
6833         return err;
6834 }
6835
6836 static unsigned long raid5_cache_scan(struct shrinker *shrink,
6837                                       struct shrink_control *sc)
6838 {
6839         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6840         unsigned long ret = SHRINK_STOP;
6841
6842         if (mutex_trylock(&conf->cache_size_mutex)) {
6843                 ret= 0;
6844                 while (ret < sc->nr_to_scan &&
6845                        conf->max_nr_stripes > conf->min_nr_stripes) {
6846                         if (drop_one_stripe(conf) == 0) {
6847                                 ret = SHRINK_STOP;
6848                                 break;
6849                         }
6850                         ret++;
6851                 }
6852                 mutex_unlock(&conf->cache_size_mutex);
6853         }
6854         return ret;
6855 }
6856
6857 static unsigned long raid5_cache_count(struct shrinker *shrink,
6858                                        struct shrink_control *sc)
6859 {
6860         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6861
6862         if (conf->max_nr_stripes < conf->min_nr_stripes)
6863                 /* unlikely, but not impossible */
6864                 return 0;
6865         return conf->max_nr_stripes - conf->min_nr_stripes;
6866 }
6867
6868 static struct r5conf *setup_conf(struct mddev *mddev)
6869 {
6870         struct r5conf *conf;
6871         int raid_disk, memory, max_disks;
6872         struct md_rdev *rdev;
6873         struct disk_info *disk;
6874         char pers_name[6];
6875         int i;
6876         int group_cnt, worker_cnt_per_group;
6877         struct r5worker_group *new_group;
6878         int ret;
6879
6880         if (mddev->new_level != 5
6881             && mddev->new_level != 4
6882             && mddev->new_level != 6) {
6883                 pr_warn("md/raid:%s: raid level not set to 4/5/6 (%d)\n",
6884                         mdname(mddev), mddev->new_level);
6885                 return ERR_PTR(-EIO);
6886         }
6887         if ((mddev->new_level == 5
6888              && !algorithm_valid_raid5(mddev->new_layout)) ||
6889             (mddev->new_level == 6
6890              && !algorithm_valid_raid6(mddev->new_layout))) {
6891                 pr_warn("md/raid:%s: layout %d not supported\n",
6892                         mdname(mddev), mddev->new_layout);
6893                 return ERR_PTR(-EIO);
6894         }
6895         if (mddev->new_level == 6 && mddev->raid_disks < 4) {
6896                 pr_warn("md/raid:%s: not enough configured devices (%d, minimum 4)\n",
6897                         mdname(mddev), mddev->raid_disks);
6898                 return ERR_PTR(-EINVAL);
6899         }
6900
6901         if (!mddev->new_chunk_sectors ||
6902             (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
6903             !is_power_of_2(mddev->new_chunk_sectors)) {
6904                 pr_warn("md/raid:%s: invalid chunk size %d\n",
6905                         mdname(mddev), mddev->new_chunk_sectors << 9);
6906                 return ERR_PTR(-EINVAL);
6907         }
6908
6909         conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
6910         if (conf == NULL)
6911                 goto abort;
6912         INIT_LIST_HEAD(&conf->free_list);
6913         INIT_LIST_HEAD(&conf->pending_list);
6914         conf->pending_data = kcalloc(PENDING_IO_MAX,
6915                                      sizeof(struct r5pending_data),
6916                                      GFP_KERNEL);
6917         if (!conf->pending_data)
6918                 goto abort;
6919         for (i = 0; i < PENDING_IO_MAX; i++)
6920                 list_add(&conf->pending_data[i].sibling, &conf->free_list);
6921         /* Don't enable multi-threading by default*/
6922         if (!alloc_thread_groups(conf, 0, &group_cnt, &worker_cnt_per_group,
6923                                  &new_group)) {
6924                 conf->group_cnt = group_cnt;
6925                 conf->worker_cnt_per_group = worker_cnt_per_group;
6926                 conf->worker_groups = new_group;
6927         } else
6928                 goto abort;
6929         spin_lock_init(&conf->device_lock);
6930         seqcount_init(&conf->gen_lock);
6931         mutex_init(&conf->cache_size_mutex);
6932         init_waitqueue_head(&conf->wait_for_quiescent);
6933         init_waitqueue_head(&conf->wait_for_stripe);
6934         init_waitqueue_head(&conf->wait_for_overlap);
6935         INIT_LIST_HEAD(&conf->handle_list);
6936         INIT_LIST_HEAD(&conf->loprio_list);
6937         INIT_LIST_HEAD(&conf->hold_list);
6938         INIT_LIST_HEAD(&conf->delayed_list);
6939         INIT_LIST_HEAD(&conf->bitmap_list);
6940         init_llist_head(&conf->released_stripes);
6941         atomic_set(&conf->active_stripes, 0);
6942         atomic_set(&conf->preread_active_stripes, 0);
6943         atomic_set(&conf->active_aligned_reads, 0);
6944         spin_lock_init(&conf->pending_bios_lock);
6945         conf->batch_bio_dispatch = true;
6946         rdev_for_each(rdev, mddev) {
6947                 if (test_bit(Journal, &rdev->flags))
6948                         continue;
6949                 if (blk_queue_nonrot(bdev_get_queue(rdev->bdev))) {
6950                         conf->batch_bio_dispatch = false;
6951                         break;
6952                 }
6953         }
6954
6955         conf->bypass_threshold = BYPASS_THRESHOLD;
6956         conf->recovery_disabled = mddev->recovery_disabled - 1;
6957
6958         conf->raid_disks = mddev->raid_disks;
6959         if (mddev->reshape_position == MaxSector)
6960                 conf->previous_raid_disks = mddev->raid_disks;
6961         else
6962                 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
6963         max_disks = max(conf->raid_disks, conf->previous_raid_disks);
6964
6965         conf->disks = kcalloc(max_disks, sizeof(struct disk_info),
6966                               GFP_KERNEL);
6967
6968         if (!conf->disks)
6969                 goto abort;
6970
6971         for (i = 0; i < max_disks; i++) {
6972                 conf->disks[i].extra_page = alloc_page(GFP_KERNEL);
6973                 if (!conf->disks[i].extra_page)
6974                         goto abort;
6975         }
6976
6977         ret = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
6978         if (ret)
6979                 goto abort;
6980         conf->mddev = mddev;
6981
6982         if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
6983                 goto abort;
6984
6985         /* We init hash_locks[0] separately to that it can be used
6986          * as the reference lock in the spin_lock_nest_lock() call
6987          * in lock_all_device_hash_locks_irq in order to convince
6988          * lockdep that we know what we are doing.
6989          */
6990         spin_lock_init(conf->hash_locks);
6991         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
6992                 spin_lock_init(conf->hash_locks + i);
6993
6994         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6995                 INIT_LIST_HEAD(conf->inactive_list + i);
6996
6997         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6998                 INIT_LIST_HEAD(conf->temp_inactive_list + i);
6999
7000         atomic_set(&conf->r5c_cached_full_stripes, 0);
7001         INIT_LIST_HEAD(&conf->r5c_full_stripe_list);
7002         atomic_set(&conf->r5c_cached_partial_stripes, 0);
7003         INIT_LIST_HEAD(&conf->r5c_partial_stripe_list);
7004         atomic_set(&conf->r5c_flushing_full_stripes, 0);
7005         atomic_set(&conf->r5c_flushing_partial_stripes, 0);
7006
7007         conf->level = mddev->new_level;
7008         conf->chunk_sectors = mddev->new_chunk_sectors;
7009         if (raid5_alloc_percpu(conf) != 0)
7010                 goto abort;
7011
7012         pr_debug("raid456: run(%s) called.\n", mdname(mddev));
7013
7014         rdev_for_each(rdev, mddev) {
7015                 raid_disk = rdev->raid_disk;
7016                 if (raid_disk >= max_disks
7017                     || raid_disk < 0 || test_bit(Journal, &rdev->flags))
7018                         continue;
7019                 disk = conf->disks + raid_disk;
7020
7021                 if (test_bit(Replacement, &rdev->flags)) {
7022                         if (disk->replacement)
7023                                 goto abort;
7024                         disk->replacement = rdev;
7025                 } else {
7026                         if (disk->rdev)
7027                                 goto abort;
7028                         disk->rdev = rdev;
7029                 }
7030
7031                 if (test_bit(In_sync, &rdev->flags)) {
7032                         char b[BDEVNAME_SIZE];
7033                         pr_info("md/raid:%s: device %s operational as raid disk %d\n",
7034                                 mdname(mddev), bdevname(rdev->bdev, b), raid_disk);
7035                 } else if (rdev->saved_raid_disk != raid_disk)
7036                         /* Cannot rely on bitmap to complete recovery */
7037                         conf->fullsync = 1;
7038         }
7039
7040         conf->level = mddev->new_level;
7041         if (conf->level == 6) {
7042                 conf->max_degraded = 2;
7043                 if (raid6_call.xor_syndrome)
7044                         conf->rmw_level = PARITY_ENABLE_RMW;
7045                 else
7046                         conf->rmw_level = PARITY_DISABLE_RMW;
7047         } else {
7048                 conf->max_degraded = 1;
7049                 conf->rmw_level = PARITY_ENABLE_RMW;
7050         }
7051         conf->algorithm = mddev->new_layout;
7052         conf->reshape_progress = mddev->reshape_position;
7053         if (conf->reshape_progress != MaxSector) {
7054                 conf->prev_chunk_sectors = mddev->chunk_sectors;
7055                 conf->prev_algo = mddev->layout;
7056         } else {
7057                 conf->prev_chunk_sectors = conf->chunk_sectors;
7058                 conf->prev_algo = conf->algorithm;
7059         }
7060
7061         conf->min_nr_stripes = NR_STRIPES;
7062         if (mddev->reshape_position != MaxSector) {
7063                 int stripes = max_t(int,
7064                         ((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4,
7065                         ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4);
7066                 conf->min_nr_stripes = max(NR_STRIPES, stripes);
7067                 if (conf->min_nr_stripes != NR_STRIPES)
7068                         pr_info("md/raid:%s: force stripe size %d for reshape\n",
7069                                 mdname(mddev), conf->min_nr_stripes);
7070         }
7071         memory = conf->min_nr_stripes * (sizeof(struct stripe_head) +
7072                  max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
7073         atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS);
7074         if (grow_stripes(conf, conf->min_nr_stripes)) {
7075                 pr_warn("md/raid:%s: couldn't allocate %dkB for buffers\n",
7076                         mdname(mddev), memory);
7077                 goto abort;
7078         } else
7079                 pr_debug("md/raid:%s: allocated %dkB\n", mdname(mddev), memory);
7080         /*
7081          * Losing a stripe head costs more than the time to refill it,
7082          * it reduces the queue depth and so can hurt throughput.
7083          * So set it rather large, scaled by number of devices.
7084          */
7085         conf->shrinker.seeks = DEFAULT_SEEKS * conf->raid_disks * 4;
7086         conf->shrinker.scan_objects = raid5_cache_scan;
7087         conf->shrinker.count_objects = raid5_cache_count;
7088         conf->shrinker.batch = 128;
7089         conf->shrinker.flags = 0;
7090         if (register_shrinker(&conf->shrinker)) {
7091                 pr_warn("md/raid:%s: couldn't register shrinker.\n",
7092                         mdname(mddev));
7093                 goto abort;
7094         }
7095
7096         sprintf(pers_name, "raid%d", mddev->new_level);
7097         conf->thread = md_register_thread(raid5d, mddev, pers_name);
7098         if (!conf->thread) {
7099                 pr_warn("md/raid:%s: couldn't allocate thread.\n",
7100                         mdname(mddev));
7101                 goto abort;
7102         }
7103
7104         return conf;
7105
7106  abort:
7107         if (conf) {
7108                 free_conf(conf);
7109                 return ERR_PTR(-EIO);
7110         } else
7111                 return ERR_PTR(-ENOMEM);
7112 }
7113
7114 static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
7115 {
7116         switch (algo) {
7117         case ALGORITHM_PARITY_0:
7118                 if (raid_disk < max_degraded)
7119                         return 1;
7120                 break;
7121         case ALGORITHM_PARITY_N:
7122                 if (raid_disk >= raid_disks - max_degraded)
7123                         return 1;
7124                 break;
7125         case ALGORITHM_PARITY_0_6:
7126                 if (raid_disk == 0 ||
7127                     raid_disk == raid_disks - 1)
7128                         return 1;
7129                 break;
7130         case ALGORITHM_LEFT_ASYMMETRIC_6:
7131         case ALGORITHM_RIGHT_ASYMMETRIC_6:
7132         case ALGORITHM_LEFT_SYMMETRIC_6:
7133         case ALGORITHM_RIGHT_SYMMETRIC_6:
7134                 if (raid_disk == raid_disks - 1)
7135                         return 1;
7136         }
7137         return 0;
7138 }
7139
7140 static int raid5_run(struct mddev *mddev)
7141 {
7142         struct r5conf *conf;
7143         int working_disks = 0;
7144         int dirty_parity_disks = 0;
7145         struct md_rdev *rdev;
7146         struct md_rdev *journal_dev = NULL;
7147         sector_t reshape_offset = 0;
7148         int i;
7149         long long min_offset_diff = 0;
7150         int first = 1;
7151
7152         if (mddev_init_writes_pending(mddev) < 0)
7153                 return -ENOMEM;
7154
7155         if (mddev->recovery_cp != MaxSector)
7156                 pr_notice("md/raid:%s: not clean -- starting background reconstruction\n",
7157                           mdname(mddev));
7158
7159         rdev_for_each(rdev, mddev) {
7160                 long long diff;
7161
7162                 if (test_bit(Journal, &rdev->flags)) {
7163                         journal_dev = rdev;
7164                         continue;
7165                 }
7166                 if (rdev->raid_disk < 0)
7167                         continue;
7168                 diff = (rdev->new_data_offset - rdev->data_offset);
7169                 if (first) {
7170                         min_offset_diff = diff;
7171                         first = 0;
7172                 } else if (mddev->reshape_backwards &&
7173                          diff < min_offset_diff)
7174                         min_offset_diff = diff;
7175                 else if (!mddev->reshape_backwards &&
7176                          diff > min_offset_diff)
7177                         min_offset_diff = diff;
7178         }
7179
7180         if ((test_bit(MD_HAS_JOURNAL, &mddev->flags) || journal_dev) &&
7181             (mddev->bitmap_info.offset || mddev->bitmap_info.file)) {
7182                 pr_notice("md/raid:%s: array cannot have both journal and bitmap\n",
7183                           mdname(mddev));
7184                 return -EINVAL;
7185         }
7186
7187         if (mddev->reshape_position != MaxSector) {
7188                 /* Check that we can continue the reshape.
7189                  * Difficulties arise if the stripe we would write to
7190                  * next is at or after the stripe we would read from next.
7191                  * For a reshape that changes the number of devices, this
7192                  * is only possible for a very short time, and mdadm makes
7193                  * sure that time appears to have past before assembling
7194                  * the array.  So we fail if that time hasn't passed.
7195                  * For a reshape that keeps the number of devices the same
7196                  * mdadm must be monitoring the reshape can keeping the
7197                  * critical areas read-only and backed up.  It will start
7198                  * the array in read-only mode, so we check for that.
7199                  */
7200                 sector_t here_new, here_old;
7201                 int old_disks;
7202                 int max_degraded = (mddev->level == 6 ? 2 : 1);
7203                 int chunk_sectors;
7204                 int new_data_disks;
7205
7206                 if (journal_dev) {
7207                         pr_warn("md/raid:%s: don't support reshape with journal - aborting.\n",
7208                                 mdname(mddev));
7209                         return -EINVAL;
7210                 }
7211
7212                 if (mddev->new_level != mddev->level) {
7213                         pr_warn("md/raid:%s: unsupported reshape required - aborting.\n",
7214                                 mdname(mddev));
7215                         return -EINVAL;
7216                 }
7217                 old_disks = mddev->raid_disks - mddev->delta_disks;
7218                 /* reshape_position must be on a new-stripe boundary, and one
7219                  * further up in new geometry must map after here in old
7220                  * geometry.
7221                  * If the chunk sizes are different, then as we perform reshape
7222                  * in units of the largest of the two, reshape_position needs
7223                  * be a multiple of the largest chunk size times new data disks.
7224                  */
7225                 here_new = mddev->reshape_position;
7226                 chunk_sectors = max(mddev->chunk_sectors, mddev->new_chunk_sectors);
7227                 new_data_disks = mddev->raid_disks - max_degraded;
7228                 if (sector_div(here_new, chunk_sectors * new_data_disks)) {
7229                         pr_warn("md/raid:%s: reshape_position not on a stripe boundary\n",
7230                                 mdname(mddev));
7231                         return -EINVAL;
7232                 }
7233                 reshape_offset = here_new * chunk_sectors;
7234                 /* here_new is the stripe we will write to */
7235                 here_old = mddev->reshape_position;
7236                 sector_div(here_old, chunk_sectors * (old_disks-max_degraded));
7237                 /* here_old is the first stripe that we might need to read
7238                  * from */
7239                 if (mddev->delta_disks == 0) {
7240                         /* We cannot be sure it is safe to start an in-place
7241                          * reshape.  It is only safe if user-space is monitoring
7242                          * and taking constant backups.
7243                          * mdadm always starts a situation like this in
7244                          * readonly mode so it can take control before
7245                          * allowing any writes.  So just check for that.
7246                          */
7247                         if (abs(min_offset_diff) >= mddev->chunk_sectors &&
7248                             abs(min_offset_diff) >= mddev->new_chunk_sectors)
7249                                 /* not really in-place - so OK */;
7250                         else if (mddev->ro == 0) {
7251                                 pr_warn("md/raid:%s: in-place reshape must be started in read-only mode - aborting\n",
7252                                         mdname(mddev));
7253                                 return -EINVAL;
7254                         }
7255                 } else if (mddev->reshape_backwards
7256                     ? (here_new * chunk_sectors + min_offset_diff <=
7257                        here_old * chunk_sectors)
7258                     : (here_new * chunk_sectors >=
7259                        here_old * chunk_sectors + (-min_offset_diff))) {
7260                         /* Reading from the same stripe as writing to - bad */
7261                         pr_warn("md/raid:%s: reshape_position too early for auto-recovery - aborting.\n",
7262                                 mdname(mddev));
7263                         return -EINVAL;
7264                 }
7265                 pr_debug("md/raid:%s: reshape will continue\n", mdname(mddev));
7266                 /* OK, we should be able to continue; */
7267         } else {
7268                 BUG_ON(mddev->level != mddev->new_level);
7269                 BUG_ON(mddev->layout != mddev->new_layout);
7270                 BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
7271                 BUG_ON(mddev->delta_disks != 0);
7272         }
7273
7274         if (test_bit(MD_HAS_JOURNAL, &mddev->flags) &&
7275             test_bit(MD_HAS_PPL, &mddev->flags)) {
7276                 pr_warn("md/raid:%s: using journal device and PPL not allowed - disabling PPL\n",
7277                         mdname(mddev));
7278                 clear_bit(MD_HAS_PPL, &mddev->flags);
7279                 clear_bit(MD_HAS_MULTIPLE_PPLS, &mddev->flags);
7280         }
7281
7282         if (mddev->private == NULL)
7283                 conf = setup_conf(mddev);
7284         else
7285                 conf = mddev->private;
7286
7287         if (IS_ERR(conf))
7288                 return PTR_ERR(conf);
7289
7290         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
7291                 if (!journal_dev) {
7292                         pr_warn("md/raid:%s: journal disk is missing, force array readonly\n",
7293                                 mdname(mddev));
7294                         mddev->ro = 1;
7295                         set_disk_ro(mddev->gendisk, 1);
7296                 } else if (mddev->recovery_cp == MaxSector)
7297                         set_bit(MD_JOURNAL_CLEAN, &mddev->flags);
7298         }
7299
7300         conf->min_offset_diff = min_offset_diff;
7301         mddev->thread = conf->thread;
7302         conf->thread = NULL;
7303         mddev->private = conf;
7304
7305         for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
7306              i++) {
7307                 rdev = conf->disks[i].rdev;
7308                 if (!rdev && conf->disks[i].replacement) {
7309                         /* The replacement is all we have yet */
7310                         rdev = conf->disks[i].replacement;
7311                         conf->disks[i].replacement = NULL;
7312                         clear_bit(Replacement, &rdev->flags);
7313                         conf->disks[i].rdev = rdev;
7314                 }
7315                 if (!rdev)
7316                         continue;
7317                 if (conf->disks[i].replacement &&
7318                     conf->reshape_progress != MaxSector) {
7319                         /* replacements and reshape simply do not mix. */
7320                         pr_warn("md: cannot handle concurrent replacement and reshape.\n");
7321                         goto abort;
7322                 }
7323                 if (test_bit(In_sync, &rdev->flags)) {
7324                         working_disks++;
7325                         continue;
7326                 }
7327                 /* This disc is not fully in-sync.  However if it
7328                  * just stored parity (beyond the recovery_offset),
7329                  * when we don't need to be concerned about the
7330                  * array being dirty.
7331                  * When reshape goes 'backwards', we never have
7332                  * partially completed devices, so we only need
7333                  * to worry about reshape going forwards.
7334                  */
7335                 /* Hack because v0.91 doesn't store recovery_offset properly. */
7336                 if (mddev->major_version == 0 &&
7337                     mddev->minor_version > 90)
7338                         rdev->recovery_offset = reshape_offset;
7339
7340                 if (rdev->recovery_offset < reshape_offset) {
7341                         /* We need to check old and new layout */
7342                         if (!only_parity(rdev->raid_disk,
7343                                          conf->algorithm,
7344                                          conf->raid_disks,
7345                                          conf->max_degraded))
7346                                 continue;
7347                 }
7348                 if (!only_parity(rdev->raid_disk,
7349                                  conf->prev_algo,
7350                                  conf->previous_raid_disks,
7351                                  conf->max_degraded))
7352                         continue;
7353                 dirty_parity_disks++;
7354         }
7355
7356         /*
7357          * 0 for a fully functional array, 1 or 2 for a degraded array.
7358          */
7359         mddev->degraded = raid5_calc_degraded(conf);
7360
7361         if (has_failed(conf)) {
7362                 pr_crit("md/raid:%s: not enough operational devices (%d/%d failed)\n",
7363                         mdname(mddev), mddev->degraded, conf->raid_disks);
7364                 goto abort;
7365         }
7366
7367         /* device size must be a multiple of chunk size */
7368         mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
7369         mddev->resync_max_sectors = mddev->dev_sectors;
7370
7371         if (mddev->degraded > dirty_parity_disks &&
7372             mddev->recovery_cp != MaxSector) {
7373                 if (test_bit(MD_HAS_PPL, &mddev->flags))
7374                         pr_crit("md/raid:%s: starting dirty degraded array with PPL.\n",
7375                                 mdname(mddev));
7376                 else if (mddev->ok_start_degraded)
7377                         pr_crit("md/raid:%s: starting dirty degraded array - data corruption possible.\n",
7378                                 mdname(mddev));
7379                 else {
7380                         pr_crit("md/raid:%s: cannot start dirty degraded array.\n",
7381                                 mdname(mddev));
7382                         goto abort;
7383                 }
7384         }
7385
7386         pr_info("md/raid:%s: raid level %d active with %d out of %d devices, algorithm %d\n",
7387                 mdname(mddev), conf->level,
7388                 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
7389                 mddev->new_layout);
7390
7391         print_raid5_conf(conf);
7392
7393         if (conf->reshape_progress != MaxSector) {
7394                 conf->reshape_safe = conf->reshape_progress;
7395                 atomic_set(&conf->reshape_stripes, 0);
7396                 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7397                 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7398                 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7399                 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7400                 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7401                                                         "reshape");
7402                 if (!mddev->sync_thread)
7403                         goto abort;
7404         }
7405
7406         /* Ok, everything is just fine now */
7407         if (mddev->to_remove == &raid5_attrs_group)
7408                 mddev->to_remove = NULL;
7409         else if (mddev->kobj.sd &&
7410             sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
7411                 pr_warn("raid5: failed to create sysfs attributes for %s\n",
7412                         mdname(mddev));
7413         md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
7414
7415         if (mddev->queue) {
7416                 int chunk_size;
7417                 /* read-ahead size must cover two whole stripes, which
7418                  * is 2 * (datadisks) * chunksize where 'n' is the
7419                  * number of raid devices
7420                  */
7421                 int data_disks = conf->previous_raid_disks - conf->max_degraded;
7422                 int stripe = data_disks *
7423                         ((mddev->chunk_sectors << 9) / PAGE_SIZE);
7424                 if (mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
7425                         mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
7426
7427                 chunk_size = mddev->chunk_sectors << 9;
7428                 blk_queue_io_min(mddev->queue, chunk_size);
7429                 blk_queue_io_opt(mddev->queue, chunk_size *
7430                                  (conf->raid_disks - conf->max_degraded));
7431                 mddev->queue->limits.raid_partial_stripes_expensive = 1;
7432                 /*
7433                  * We can only discard a whole stripe. It doesn't make sense to
7434                  * discard data disk but write parity disk
7435                  */
7436                 stripe = stripe * PAGE_SIZE;
7437                 /* Round up to power of 2, as discard handling
7438                  * currently assumes that */
7439                 while ((stripe-1) & stripe)
7440                         stripe = (stripe | (stripe-1)) + 1;
7441                 mddev->queue->limits.discard_alignment = stripe;
7442                 mddev->queue->limits.discard_granularity = stripe;
7443
7444                 blk_queue_max_write_same_sectors(mddev->queue, 0);
7445                 blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
7446
7447                 rdev_for_each(rdev, mddev) {
7448                         disk_stack_limits(mddev->gendisk, rdev->bdev,
7449                                           rdev->data_offset << 9);
7450                         disk_stack_limits(mddev->gendisk, rdev->bdev,
7451                                           rdev->new_data_offset << 9);
7452                 }
7453
7454                 /*
7455                  * zeroing is required, otherwise data
7456                  * could be lost. Consider a scenario: discard a stripe
7457                  * (the stripe could be inconsistent if
7458                  * discard_zeroes_data is 0); write one disk of the
7459                  * stripe (the stripe could be inconsistent again
7460                  * depending on which disks are used to calculate
7461                  * parity); the disk is broken; The stripe data of this
7462                  * disk is lost.
7463                  *
7464                  * We only allow DISCARD if the sysadmin has confirmed that
7465                  * only safe devices are in use by setting a module parameter.
7466                  * A better idea might be to turn DISCARD into WRITE_ZEROES
7467                  * requests, as that is required to be safe.
7468                  */
7469                 if (devices_handle_discard_safely &&
7470                     mddev->queue->limits.max_discard_sectors >= (stripe >> 9) &&
7471                     mddev->queue->limits.discard_granularity >= stripe)
7472                         blk_queue_flag_set(QUEUE_FLAG_DISCARD,
7473                                                 mddev->queue);
7474                 else
7475                         blk_queue_flag_clear(QUEUE_FLAG_DISCARD,
7476                                                 mddev->queue);
7477
7478                 blk_queue_max_hw_sectors(mddev->queue, UINT_MAX);
7479         }
7480
7481         if (log_init(conf, journal_dev, raid5_has_ppl(conf)))
7482                 goto abort;
7483
7484         return 0;
7485 abort:
7486         md_unregister_thread(&mddev->thread);
7487         print_raid5_conf(conf);
7488         free_conf(conf);
7489         mddev->private = NULL;
7490         pr_warn("md/raid:%s: failed to run raid set.\n", mdname(mddev));
7491         return -EIO;
7492 }
7493
7494 static void raid5_free(struct mddev *mddev, void *priv)
7495 {
7496         struct r5conf *conf = priv;
7497
7498         free_conf(conf);
7499         mddev->to_remove = &raid5_attrs_group;
7500 }
7501
7502 static void raid5_status(struct seq_file *seq, struct mddev *mddev)
7503 {
7504         struct r5conf *conf = mddev->private;
7505         int i;
7506
7507         seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
7508                 conf->chunk_sectors / 2, mddev->layout);
7509         seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
7510         rcu_read_lock();
7511         for (i = 0; i < conf->raid_disks; i++) {
7512                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
7513                 seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
7514         }
7515         rcu_read_unlock();
7516         seq_printf (seq, "]");
7517 }
7518
7519 static void print_raid5_conf (struct r5conf *conf)
7520 {
7521         int i;
7522         struct disk_info *tmp;
7523
7524         pr_debug("RAID conf printout:\n");
7525         if (!conf) {
7526                 pr_debug("(conf==NULL)\n");
7527                 return;
7528         }
7529         pr_debug(" --- level:%d rd:%d wd:%d\n", conf->level,
7530                conf->raid_disks,
7531                conf->raid_disks - conf->mddev->degraded);
7532
7533         for (i = 0; i < conf->raid_disks; i++) {
7534                 char b[BDEVNAME_SIZE];
7535                 tmp = conf->disks + i;
7536                 if (tmp->rdev)
7537                         pr_debug(" disk %d, o:%d, dev:%s\n",
7538                                i, !test_bit(Faulty, &tmp->rdev->flags),
7539                                bdevname(tmp->rdev->bdev, b));
7540         }
7541 }
7542
7543 static int raid5_spare_active(struct mddev *mddev)
7544 {
7545         int i;
7546         struct r5conf *conf = mddev->private;
7547         struct disk_info *tmp;
7548         int count = 0;
7549         unsigned long flags;
7550
7551         for (i = 0; i < conf->raid_disks; i++) {
7552                 tmp = conf->disks + i;
7553                 if (tmp->replacement
7554                     && tmp->replacement->recovery_offset == MaxSector
7555                     && !test_bit(Faulty, &tmp->replacement->flags)
7556                     && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
7557                         /* Replacement has just become active. */
7558                         if (!tmp->rdev
7559                             || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
7560                                 count++;
7561                         if (tmp->rdev) {
7562                                 /* Replaced device not technically faulty,
7563                                  * but we need to be sure it gets removed
7564                                  * and never re-added.
7565                                  */
7566                                 set_bit(Faulty, &tmp->rdev->flags);
7567                                 sysfs_notify_dirent_safe(
7568                                         tmp->rdev->sysfs_state);
7569                         }
7570                         sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
7571                 } else if (tmp->rdev
7572                     && tmp->rdev->recovery_offset == MaxSector
7573                     && !test_bit(Faulty, &tmp->rdev->flags)
7574                     && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
7575                         count++;
7576                         sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
7577                 }
7578         }
7579         spin_lock_irqsave(&conf->device_lock, flags);
7580         mddev->degraded = raid5_calc_degraded(conf);
7581         spin_unlock_irqrestore(&conf->device_lock, flags);
7582         print_raid5_conf(conf);
7583         return count;
7584 }
7585
7586 static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
7587 {
7588         struct r5conf *conf = mddev->private;
7589         int err = 0;
7590         int number = rdev->raid_disk;
7591         struct md_rdev **rdevp;
7592         struct disk_info *p = conf->disks + number;
7593
7594         print_raid5_conf(conf);
7595         if (test_bit(Journal, &rdev->flags) && conf->log) {
7596                 /*
7597                  * we can't wait pending write here, as this is called in
7598                  * raid5d, wait will deadlock.
7599                  * neilb: there is no locking about new writes here,
7600                  * so this cannot be safe.
7601                  */
7602                 if (atomic_read(&conf->active_stripes) ||
7603                     atomic_read(&conf->r5c_cached_full_stripes) ||
7604                     atomic_read(&conf->r5c_cached_partial_stripes)) {
7605                         return -EBUSY;
7606                 }
7607                 log_exit(conf);
7608                 return 0;
7609         }
7610         if (rdev == p->rdev)
7611                 rdevp = &p->rdev;
7612         else if (rdev == p->replacement)
7613                 rdevp = &p->replacement;
7614         else
7615                 return 0;
7616
7617         if (number >= conf->raid_disks &&
7618             conf->reshape_progress == MaxSector)
7619                 clear_bit(In_sync, &rdev->flags);
7620
7621         if (test_bit(In_sync, &rdev->flags) ||
7622             atomic_read(&rdev->nr_pending)) {
7623                 err = -EBUSY;
7624                 goto abort;
7625         }
7626         /* Only remove non-faulty devices if recovery
7627          * isn't possible.
7628          */
7629         if (!test_bit(Faulty, &rdev->flags) &&
7630             mddev->recovery_disabled != conf->recovery_disabled &&
7631             !has_failed(conf) &&
7632             (!p->replacement || p->replacement == rdev) &&
7633             number < conf->raid_disks) {
7634                 err = -EBUSY;
7635                 goto abort;
7636         }
7637         *rdevp = NULL;
7638         if (!test_bit(RemoveSynchronized, &rdev->flags)) {
7639                 synchronize_rcu();
7640                 if (atomic_read(&rdev->nr_pending)) {
7641                         /* lost the race, try later */
7642                         err = -EBUSY;
7643                         *rdevp = rdev;
7644                 }
7645         }
7646         if (!err) {
7647                 err = log_modify(conf, rdev, false);
7648                 if (err)
7649                         goto abort;
7650         }
7651         if (p->replacement) {
7652                 /* We must have just cleared 'rdev' */
7653                 p->rdev = p->replacement;
7654                 clear_bit(Replacement, &p->replacement->flags);
7655                 smp_mb(); /* Make sure other CPUs may see both as identical
7656                            * but will never see neither - if they are careful
7657                            */
7658                 p->replacement = NULL;
7659
7660                 if (!err)
7661                         err = log_modify(conf, p->rdev, true);
7662         }
7663
7664         clear_bit(WantReplacement, &rdev->flags);
7665 abort:
7666
7667         print_raid5_conf(conf);
7668         return err;
7669 }
7670
7671 static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
7672 {
7673         struct r5conf *conf = mddev->private;
7674         int ret, err = -EEXIST;
7675         int disk;
7676         struct disk_info *p;
7677         int first = 0;
7678         int last = conf->raid_disks - 1;
7679
7680         if (test_bit(Journal, &rdev->flags)) {
7681                 if (conf->log)
7682                         return -EBUSY;
7683
7684                 rdev->raid_disk = 0;
7685                 /*
7686                  * The array is in readonly mode if journal is missing, so no
7687                  * write requests running. We should be safe
7688                  */
7689                 ret = log_init(conf, rdev, false);
7690                 if (ret)
7691                         return ret;
7692
7693                 ret = r5l_start(conf->log);
7694                 if (ret)
7695                         return ret;
7696
7697                 return 0;
7698         }
7699         if (mddev->recovery_disabled == conf->recovery_disabled)
7700                 return -EBUSY;
7701
7702         if (rdev->saved_raid_disk < 0 && has_failed(conf))
7703                 /* no point adding a device */
7704                 return -EINVAL;
7705
7706         if (rdev->raid_disk >= 0)
7707                 first = last = rdev->raid_disk;
7708
7709         /*
7710          * find the disk ... but prefer rdev->saved_raid_disk
7711          * if possible.
7712          */
7713         if (rdev->saved_raid_disk >= 0 &&
7714             rdev->saved_raid_disk >= first &&
7715             conf->disks[rdev->saved_raid_disk].rdev == NULL)
7716                 first = rdev->saved_raid_disk;
7717
7718         for (disk = first; disk <= last; disk++) {
7719                 p = conf->disks + disk;
7720                 if (p->rdev == NULL) {
7721                         clear_bit(In_sync, &rdev->flags);
7722                         rdev->raid_disk = disk;
7723                         if (rdev->saved_raid_disk != disk)
7724                                 conf->fullsync = 1;
7725                         rcu_assign_pointer(p->rdev, rdev);
7726
7727                         err = log_modify(conf, rdev, true);
7728
7729                         goto out;
7730                 }
7731         }
7732         for (disk = first; disk <= last; disk++) {
7733                 p = conf->disks + disk;
7734                 if (test_bit(WantReplacement, &p->rdev->flags) &&
7735                     p->replacement == NULL) {
7736                         clear_bit(In_sync, &rdev->flags);
7737                         set_bit(Replacement, &rdev->flags);
7738                         rdev->raid_disk = disk;
7739                         err = 0;
7740                         conf->fullsync = 1;
7741                         rcu_assign_pointer(p->replacement, rdev);
7742                         break;
7743                 }
7744         }
7745 out:
7746         print_raid5_conf(conf);
7747         return err;
7748 }
7749
7750 static int raid5_resize(struct mddev *mddev, sector_t sectors)
7751 {
7752         /* no resync is happening, and there is enough space
7753          * on all devices, so we can resize.
7754          * We need to make sure resync covers any new space.
7755          * If the array is shrinking we should possibly wait until
7756          * any io in the removed space completes, but it hardly seems
7757          * worth it.
7758          */
7759         sector_t newsize;
7760         struct r5conf *conf = mddev->private;
7761
7762         if (raid5_has_log(conf) || raid5_has_ppl(conf))
7763                 return -EINVAL;
7764         sectors &= ~((sector_t)conf->chunk_sectors - 1);
7765         newsize = raid5_size(mddev, sectors, mddev->raid_disks);
7766         if (mddev->external_size &&
7767             mddev->array_sectors > newsize)
7768                 return -EINVAL;
7769         if (mddev->bitmap) {
7770                 int ret = md_bitmap_resize(mddev->bitmap, sectors, 0, 0);
7771                 if (ret)
7772                         return ret;
7773         }
7774         md_set_array_sectors(mddev, newsize);
7775         if (sectors > mddev->dev_sectors &&
7776             mddev->recovery_cp > mddev->dev_sectors) {
7777                 mddev->recovery_cp = mddev->dev_sectors;
7778                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7779         }
7780         mddev->dev_sectors = sectors;
7781         mddev->resync_max_sectors = sectors;
7782         return 0;
7783 }
7784
7785 static int check_stripe_cache(struct mddev *mddev)
7786 {
7787         /* Can only proceed if there are plenty of stripe_heads.
7788          * We need a minimum of one full stripe,, and for sensible progress
7789          * it is best to have about 4 times that.
7790          * If we require 4 times, then the default 256 4K stripe_heads will
7791          * allow for chunk sizes up to 256K, which is probably OK.
7792          * If the chunk size is greater, user-space should request more
7793          * stripe_heads first.
7794          */
7795         struct r5conf *conf = mddev->private;
7796         if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4
7797             > conf->min_nr_stripes ||
7798             ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4
7799             > conf->min_nr_stripes) {
7800                 pr_warn("md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
7801                         mdname(mddev),
7802                         ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
7803                          / STRIPE_SIZE)*4);
7804                 return 0;
7805         }
7806         return 1;
7807 }
7808
7809 static int check_reshape(struct mddev *mddev)
7810 {
7811         struct r5conf *conf = mddev->private;
7812
7813         if (raid5_has_log(conf) || raid5_has_ppl(conf))
7814                 return -EINVAL;
7815         if (mddev->delta_disks == 0 &&
7816             mddev->new_layout == mddev->layout &&
7817             mddev->new_chunk_sectors == mddev->chunk_sectors)
7818                 return 0; /* nothing to do */
7819         if (has_failed(conf))
7820                 return -EINVAL;
7821         if (mddev->delta_disks < 0 && mddev->reshape_position == MaxSector) {
7822                 /* We might be able to shrink, but the devices must
7823                  * be made bigger first.
7824                  * For raid6, 4 is the minimum size.
7825                  * Otherwise 2 is the minimum
7826                  */
7827                 int min = 2;
7828                 if (mddev->level == 6)
7829                         min = 4;
7830                 if (mddev->raid_disks + mddev->delta_disks < min)
7831                         return -EINVAL;
7832         }
7833
7834         if (!check_stripe_cache(mddev))
7835                 return -ENOSPC;
7836
7837         if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
7838             mddev->delta_disks > 0)
7839                 if (resize_chunks(conf,
7840                                   conf->previous_raid_disks
7841                                   + max(0, mddev->delta_disks),
7842                                   max(mddev->new_chunk_sectors,
7843                                       mddev->chunk_sectors)
7844                             ) < 0)
7845                         return -ENOMEM;
7846
7847         if (conf->previous_raid_disks + mddev->delta_disks <= conf->pool_size)
7848                 return 0; /* never bother to shrink */
7849         return resize_stripes(conf, (conf->previous_raid_disks
7850                                      + mddev->delta_disks));
7851 }
7852
7853 static int raid5_start_reshape(struct mddev *mddev)
7854 {
7855         struct r5conf *conf = mddev->private;
7856         struct md_rdev *rdev;
7857         int spares = 0;
7858         unsigned long flags;
7859
7860         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
7861                 return -EBUSY;
7862
7863         if (!check_stripe_cache(mddev))
7864                 return -ENOSPC;
7865
7866         if (has_failed(conf))
7867                 return -EINVAL;
7868
7869         rdev_for_each(rdev, mddev) {
7870                 if (!test_bit(In_sync, &rdev->flags)
7871                     && !test_bit(Faulty, &rdev->flags))
7872                         spares++;
7873         }
7874
7875         if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
7876                 /* Not enough devices even to make a degraded array
7877                  * of that size
7878                  */
7879                 return -EINVAL;
7880
7881         /* Refuse to reduce size of the array.  Any reductions in
7882          * array size must be through explicit setting of array_size
7883          * attribute.
7884          */
7885         if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
7886             < mddev->array_sectors) {
7887                 pr_warn("md/raid:%s: array size must be reduced before number of disks\n",
7888                         mdname(mddev));
7889                 return -EINVAL;
7890         }
7891
7892         atomic_set(&conf->reshape_stripes, 0);
7893         spin_lock_irq(&conf->device_lock);
7894         write_seqcount_begin(&conf->gen_lock);
7895         conf->previous_raid_disks = conf->raid_disks;
7896         conf->raid_disks += mddev->delta_disks;
7897         conf->prev_chunk_sectors = conf->chunk_sectors;
7898         conf->chunk_sectors = mddev->new_chunk_sectors;
7899         conf->prev_algo = conf->algorithm;
7900         conf->algorithm = mddev->new_layout;
7901         conf->generation++;
7902         /* Code that selects data_offset needs to see the generation update
7903          * if reshape_progress has been set - so a memory barrier needed.
7904          */
7905         smp_mb();
7906         if (mddev->reshape_backwards)
7907                 conf->reshape_progress = raid5_size(mddev, 0, 0);
7908         else
7909                 conf->reshape_progress = 0;
7910         conf->reshape_safe = conf->reshape_progress;
7911         write_seqcount_end(&conf->gen_lock);
7912         spin_unlock_irq(&conf->device_lock);
7913
7914         /* Now make sure any requests that proceeded on the assumption
7915          * the reshape wasn't running - like Discard or Read - have
7916          * completed.
7917          */
7918         mddev_suspend(mddev);
7919         mddev_resume(mddev);
7920
7921         /* Add some new drives, as many as will fit.
7922          * We know there are enough to make the newly sized array work.
7923          * Don't add devices if we are reducing the number of
7924          * devices in the array.  This is because it is not possible
7925          * to correctly record the "partially reconstructed" state of
7926          * such devices during the reshape and confusion could result.
7927          */
7928         if (mddev->delta_disks >= 0) {
7929                 rdev_for_each(rdev, mddev)
7930                         if (rdev->raid_disk < 0 &&
7931                             !test_bit(Faulty, &rdev->flags)) {
7932                                 if (raid5_add_disk(mddev, rdev) == 0) {
7933                                         if (rdev->raid_disk
7934                                             >= conf->previous_raid_disks)
7935                                                 set_bit(In_sync, &rdev->flags);
7936                                         else
7937                                                 rdev->recovery_offset = 0;
7938
7939                                         if (sysfs_link_rdev(mddev, rdev))
7940                                                 /* Failure here is OK */;
7941                                 }
7942                         } else if (rdev->raid_disk >= conf->previous_raid_disks
7943                                    && !test_bit(Faulty, &rdev->flags)) {
7944                                 /* This is a spare that was manually added */
7945                                 set_bit(In_sync, &rdev->flags);
7946                         }
7947
7948                 /* When a reshape changes the number of devices,
7949                  * ->degraded is measured against the larger of the
7950                  * pre and post number of devices.
7951                  */
7952                 spin_lock_irqsave(&conf->device_lock, flags);
7953                 mddev->degraded = raid5_calc_degraded(conf);
7954                 spin_unlock_irqrestore(&conf->device_lock, flags);
7955         }
7956         mddev->raid_disks = conf->raid_disks;
7957         mddev->reshape_position = conf->reshape_progress;
7958         set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
7959
7960         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7961         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7962         clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
7963         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7964         set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7965         mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7966                                                 "reshape");
7967         if (!mddev->sync_thread) {
7968                 mddev->recovery = 0;
7969                 spin_lock_irq(&conf->device_lock);
7970                 write_seqcount_begin(&conf->gen_lock);
7971                 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
7972                 mddev->new_chunk_sectors =
7973                         conf->chunk_sectors = conf->prev_chunk_sectors;
7974                 mddev->new_layout = conf->algorithm = conf->prev_algo;
7975                 rdev_for_each(rdev, mddev)
7976                         rdev->new_data_offset = rdev->data_offset;
7977                 smp_wmb();
7978                 conf->generation --;
7979                 conf->reshape_progress = MaxSector;
7980                 mddev->reshape_position = MaxSector;
7981                 write_seqcount_end(&conf->gen_lock);
7982                 spin_unlock_irq(&conf->device_lock);
7983                 return -EAGAIN;
7984         }
7985         conf->reshape_checkpoint = jiffies;
7986         md_wakeup_thread(mddev->sync_thread);
7987         md_new_event(mddev);
7988         return 0;
7989 }
7990
7991 /* This is called from the reshape thread and should make any
7992  * changes needed in 'conf'
7993  */
7994 static void end_reshape(struct r5conf *conf)
7995 {
7996
7997         if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
7998                 struct md_rdev *rdev;
7999
8000                 spin_lock_irq(&conf->device_lock);
8001                 conf->previous_raid_disks = conf->raid_disks;
8002                 md_finish_reshape(conf->mddev);
8003                 smp_wmb();
8004                 conf->reshape_progress = MaxSector;
8005                 conf->mddev->reshape_position = MaxSector;
8006                 rdev_for_each(rdev, conf->mddev)
8007                         if (rdev->raid_disk >= 0 &&
8008                             !test_bit(Journal, &rdev->flags) &&
8009                             !test_bit(In_sync, &rdev->flags))
8010                                 rdev->recovery_offset = MaxSector;
8011                 spin_unlock_irq(&conf->device_lock);
8012                 wake_up(&conf->wait_for_overlap);
8013
8014                 /* read-ahead size must cover two whole stripes, which is
8015                  * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
8016                  */
8017                 if (conf->mddev->queue) {
8018                         int data_disks = conf->raid_disks - conf->max_degraded;
8019                         int stripe = data_disks * ((conf->chunk_sectors << 9)
8020                                                    / PAGE_SIZE);
8021                         if (conf->mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
8022                                 conf->mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
8023                 }
8024         }
8025 }
8026
8027 /* This is called from the raid5d thread with mddev_lock held.
8028  * It makes config changes to the device.
8029  */
8030 static void raid5_finish_reshape(struct mddev *mddev)
8031 {
8032         struct r5conf *conf = mddev->private;
8033
8034         if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
8035
8036                 if (mddev->delta_disks <= 0) {
8037                         int d;
8038                         spin_lock_irq(&conf->device_lock);
8039                         mddev->degraded = raid5_calc_degraded(conf);
8040                         spin_unlock_irq(&conf->device_lock);
8041                         for (d = conf->raid_disks ;
8042                              d < conf->raid_disks - mddev->delta_disks;
8043                              d++) {
8044                                 struct md_rdev *rdev = conf->disks[d].rdev;
8045                                 if (rdev)
8046                                         clear_bit(In_sync, &rdev->flags);
8047                                 rdev = conf->disks[d].replacement;
8048                                 if (rdev)
8049                                         clear_bit(In_sync, &rdev->flags);
8050                         }
8051                 }
8052                 mddev->layout = conf->algorithm;
8053                 mddev->chunk_sectors = conf->chunk_sectors;
8054                 mddev->reshape_position = MaxSector;
8055                 mddev->delta_disks = 0;
8056                 mddev->reshape_backwards = 0;
8057         }
8058 }
8059
8060 static void raid5_quiesce(struct mddev *mddev, int quiesce)
8061 {
8062         struct r5conf *conf = mddev->private;
8063
8064         if (quiesce) {
8065                 /* stop all writes */
8066                 lock_all_device_hash_locks_irq(conf);
8067                 /* '2' tells resync/reshape to pause so that all
8068                  * active stripes can drain
8069                  */
8070                 r5c_flush_cache(conf, INT_MAX);
8071                 conf->quiesce = 2;
8072                 wait_event_cmd(conf->wait_for_quiescent,
8073                                     atomic_read(&conf->active_stripes) == 0 &&
8074                                     atomic_read(&conf->active_aligned_reads) == 0,
8075                                     unlock_all_device_hash_locks_irq(conf),
8076                                     lock_all_device_hash_locks_irq(conf));
8077                 conf->quiesce = 1;
8078                 unlock_all_device_hash_locks_irq(conf);
8079                 /* allow reshape to continue */
8080                 wake_up(&conf->wait_for_overlap);
8081         } else {
8082                 /* re-enable writes */
8083                 lock_all_device_hash_locks_irq(conf);
8084                 conf->quiesce = 0;
8085                 wake_up(&conf->wait_for_quiescent);
8086                 wake_up(&conf->wait_for_overlap);
8087                 unlock_all_device_hash_locks_irq(conf);
8088         }
8089         log_quiesce(conf, quiesce);
8090 }
8091
8092 static void *raid45_takeover_raid0(struct mddev *mddev, int level)
8093 {
8094         struct r0conf *raid0_conf = mddev->private;
8095         sector_t sectors;
8096
8097         /* for raid0 takeover only one zone is supported */
8098         if (raid0_conf->nr_strip_zones > 1) {
8099                 pr_warn("md/raid:%s: cannot takeover raid0 with more than one zone.\n",
8100                         mdname(mddev));
8101                 return ERR_PTR(-EINVAL);
8102         }
8103
8104         sectors = raid0_conf->strip_zone[0].zone_end;
8105         sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
8106         mddev->dev_sectors = sectors;
8107         mddev->new_level = level;
8108         mddev->new_layout = ALGORITHM_PARITY_N;
8109         mddev->new_chunk_sectors = mddev->chunk_sectors;
8110         mddev->raid_disks += 1;
8111         mddev->delta_disks = 1;
8112         /* make sure it will be not marked as dirty */
8113         mddev->recovery_cp = MaxSector;
8114
8115         return setup_conf(mddev);
8116 }
8117
8118 static void *raid5_takeover_raid1(struct mddev *mddev)
8119 {
8120         int chunksect;
8121         void *ret;
8122
8123         if (mddev->raid_disks != 2 ||
8124             mddev->degraded > 1)
8125                 return ERR_PTR(-EINVAL);
8126
8127         /* Should check if there are write-behind devices? */
8128
8129         chunksect = 64*2; /* 64K by default */
8130
8131         /* The array must be an exact multiple of chunksize */
8132         while (chunksect && (mddev->array_sectors & (chunksect-1)))
8133                 chunksect >>= 1;
8134
8135         if ((chunksect<<9) < STRIPE_SIZE)
8136                 /* array size does not allow a suitable chunk size */
8137                 return ERR_PTR(-EINVAL);
8138
8139         mddev->new_level = 5;
8140         mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
8141         mddev->new_chunk_sectors = chunksect;
8142
8143         ret = setup_conf(mddev);
8144         if (!IS_ERR(ret))
8145                 mddev_clear_unsupported_flags(mddev,
8146                         UNSUPPORTED_MDDEV_FLAGS);
8147         return ret;
8148 }
8149
8150 static void *raid5_takeover_raid6(struct mddev *mddev)
8151 {
8152         int new_layout;
8153
8154         switch (mddev->layout) {
8155         case ALGORITHM_LEFT_ASYMMETRIC_6:
8156                 new_layout = ALGORITHM_LEFT_ASYMMETRIC;
8157                 break;
8158         case ALGORITHM_RIGHT_ASYMMETRIC_6:
8159                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
8160                 break;
8161         case ALGORITHM_LEFT_SYMMETRIC_6:
8162                 new_layout = ALGORITHM_LEFT_SYMMETRIC;
8163                 break;
8164         case ALGORITHM_RIGHT_SYMMETRIC_6:
8165                 new_layout = ALGORITHM_RIGHT_SYMMETRIC;
8166                 break;
8167         case ALGORITHM_PARITY_0_6:
8168                 new_layout = ALGORITHM_PARITY_0;
8169                 break;
8170         case ALGORITHM_PARITY_N:
8171                 new_layout = ALGORITHM_PARITY_N;
8172                 break;
8173         default:
8174                 return ERR_PTR(-EINVAL);
8175         }
8176         mddev->new_level = 5;
8177         mddev->new_layout = new_layout;
8178         mddev->delta_disks = -1;
8179         mddev->raid_disks -= 1;
8180         return setup_conf(mddev);
8181 }
8182
8183 static int raid5_check_reshape(struct mddev *mddev)
8184 {
8185         /* For a 2-drive array, the layout and chunk size can be changed
8186          * immediately as not restriping is needed.
8187          * For larger arrays we record the new value - after validation
8188          * to be used by a reshape pass.
8189          */
8190         struct r5conf *conf = mddev->private;
8191         int new_chunk = mddev->new_chunk_sectors;
8192
8193         if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
8194                 return -EINVAL;
8195         if (new_chunk > 0) {
8196                 if (!is_power_of_2(new_chunk))
8197                         return -EINVAL;
8198                 if (new_chunk < (PAGE_SIZE>>9))
8199                         return -EINVAL;
8200                 if (mddev->array_sectors & (new_chunk-1))
8201                         /* not factor of array size */
8202                         return -EINVAL;
8203         }
8204
8205         /* They look valid */
8206
8207         if (mddev->raid_disks == 2) {
8208                 /* can make the change immediately */
8209                 if (mddev->new_layout >= 0) {
8210                         conf->algorithm = mddev->new_layout;
8211                         mddev->layout = mddev->new_layout;
8212                 }
8213                 if (new_chunk > 0) {
8214                         conf->chunk_sectors = new_chunk ;
8215                         mddev->chunk_sectors = new_chunk;
8216                 }
8217                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8218                 md_wakeup_thread(mddev->thread);
8219         }
8220         return check_reshape(mddev);
8221 }
8222
8223 static int raid6_check_reshape(struct mddev *mddev)
8224 {
8225         int new_chunk = mddev->new_chunk_sectors;
8226
8227         if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
8228                 return -EINVAL;
8229         if (new_chunk > 0) {
8230                 if (!is_power_of_2(new_chunk))
8231                         return -EINVAL;
8232                 if (new_chunk < (PAGE_SIZE >> 9))
8233                         return -EINVAL;
8234                 if (mddev->array_sectors & (new_chunk-1))
8235                         /* not factor of array size */
8236                         return -EINVAL;
8237         }
8238
8239         /* They look valid */
8240         return check_reshape(mddev);
8241 }
8242
8243 static void *raid5_takeover(struct mddev *mddev)
8244 {
8245         /* raid5 can take over:
8246          *  raid0 - if there is only one strip zone - make it a raid4 layout
8247          *  raid1 - if there are two drives.  We need to know the chunk size
8248          *  raid4 - trivial - just use a raid4 layout.
8249          *  raid6 - Providing it is a *_6 layout
8250          */
8251         if (mddev->level == 0)
8252                 return raid45_takeover_raid0(mddev, 5);
8253         if (mddev->level == 1)
8254                 return raid5_takeover_raid1(mddev);
8255         if (mddev->level == 4) {
8256                 mddev->new_layout = ALGORITHM_PARITY_N;
8257                 mddev->new_level = 5;
8258                 return setup_conf(mddev);
8259         }
8260         if (mddev->level == 6)
8261                 return raid5_takeover_raid6(mddev);
8262
8263         return ERR_PTR(-EINVAL);
8264 }
8265
8266 static void *raid4_takeover(struct mddev *mddev)
8267 {
8268         /* raid4 can take over:
8269          *  raid0 - if there is only one strip zone
8270          *  raid5 - if layout is right
8271          */
8272         if (mddev->level == 0)
8273                 return raid45_takeover_raid0(mddev, 4);
8274         if (mddev->level == 5 &&
8275             mddev->layout == ALGORITHM_PARITY_N) {
8276                 mddev->new_layout = 0;
8277                 mddev->new_level = 4;
8278                 return setup_conf(mddev);
8279         }
8280         return ERR_PTR(-EINVAL);
8281 }
8282
8283 static struct md_personality raid5_personality;
8284
8285 static void *raid6_takeover(struct mddev *mddev)
8286 {
8287         /* Currently can only take over a raid5.  We map the
8288          * personality to an equivalent raid6 personality
8289          * with the Q block at the end.
8290          */
8291         int new_layout;
8292
8293         if (mddev->pers != &raid5_personality)
8294                 return ERR_PTR(-EINVAL);
8295         if (mddev->degraded > 1)
8296                 return ERR_PTR(-EINVAL);
8297         if (mddev->raid_disks > 253)
8298                 return ERR_PTR(-EINVAL);
8299         if (mddev->raid_disks < 3)
8300                 return ERR_PTR(-EINVAL);
8301
8302         switch (mddev->layout) {
8303         case ALGORITHM_LEFT_ASYMMETRIC:
8304                 new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
8305                 break;
8306         case ALGORITHM_RIGHT_ASYMMETRIC:
8307                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
8308                 break;
8309         case ALGORITHM_LEFT_SYMMETRIC:
8310                 new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
8311                 break;
8312         case ALGORITHM_RIGHT_SYMMETRIC:
8313                 new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
8314                 break;
8315         case ALGORITHM_PARITY_0:
8316                 new_layout = ALGORITHM_PARITY_0_6;
8317                 break;
8318         case ALGORITHM_PARITY_N:
8319                 new_layout = ALGORITHM_PARITY_N;
8320                 break;
8321         default:
8322                 return ERR_PTR(-EINVAL);
8323         }
8324         mddev->new_level = 6;
8325         mddev->new_layout = new_layout;
8326         mddev->delta_disks = 1;
8327         mddev->raid_disks += 1;
8328         return setup_conf(mddev);
8329 }
8330
8331 static int raid5_change_consistency_policy(struct mddev *mddev, const char *buf)
8332 {
8333         struct r5conf *conf;
8334         int err;
8335
8336         err = mddev_lock(mddev);
8337         if (err)
8338                 return err;
8339         conf = mddev->private;
8340         if (!conf) {
8341                 mddev_unlock(mddev);
8342                 return -ENODEV;
8343         }
8344
8345         if (strncmp(buf, "ppl", 3) == 0) {
8346                 /* ppl only works with RAID 5 */
8347                 if (!raid5_has_ppl(conf) && conf->level == 5) {
8348                         err = log_init(conf, NULL, true);
8349                         if (!err) {
8350                                 err = resize_stripes(conf, conf->pool_size);
8351                                 if (err)
8352                                         log_exit(conf);
8353                         }
8354                 } else
8355                         err = -EINVAL;
8356         } else if (strncmp(buf, "resync", 6) == 0) {
8357                 if (raid5_has_ppl(conf)) {
8358                         mddev_suspend(mddev);
8359                         log_exit(conf);
8360                         mddev_resume(mddev);
8361                         err = resize_stripes(conf, conf->pool_size);
8362                 } else if (test_bit(MD_HAS_JOURNAL, &conf->mddev->flags) &&
8363                            r5l_log_disk_error(conf)) {
8364                         bool journal_dev_exists = false;
8365                         struct md_rdev *rdev;
8366
8367                         rdev_for_each(rdev, mddev)
8368                                 if (test_bit(Journal, &rdev->flags)) {
8369                                         journal_dev_exists = true;
8370                                         break;
8371                                 }
8372
8373                         if (!journal_dev_exists) {
8374                                 mddev_suspend(mddev);
8375                                 clear_bit(MD_HAS_JOURNAL, &mddev->flags);
8376                                 mddev_resume(mddev);
8377                         } else  /* need remove journal device first */
8378                                 err = -EBUSY;
8379                 } else
8380                         err = -EINVAL;
8381         } else {
8382                 err = -EINVAL;
8383         }
8384
8385         if (!err)
8386                 md_update_sb(mddev, 1);
8387
8388         mddev_unlock(mddev);
8389
8390         return err;
8391 }
8392
8393 static int raid5_start(struct mddev *mddev)
8394 {
8395         struct r5conf *conf = mddev->private;
8396
8397         return r5l_start(conf->log);
8398 }
8399
8400 static struct md_personality raid6_personality =
8401 {
8402         .name           = "raid6",
8403         .level          = 6,
8404         .owner          = THIS_MODULE,
8405         .make_request   = raid5_make_request,
8406         .run            = raid5_run,
8407         .start          = raid5_start,
8408         .free           = raid5_free,
8409         .status         = raid5_status,
8410         .error_handler  = raid5_error,
8411         .hot_add_disk   = raid5_add_disk,
8412         .hot_remove_disk= raid5_remove_disk,
8413         .spare_active   = raid5_spare_active,
8414         .sync_request   = raid5_sync_request,
8415         .resize         = raid5_resize,
8416         .size           = raid5_size,
8417         .check_reshape  = raid6_check_reshape,
8418         .start_reshape  = raid5_start_reshape,
8419         .finish_reshape = raid5_finish_reshape,
8420         .quiesce        = raid5_quiesce,
8421         .takeover       = raid6_takeover,
8422         .congested      = raid5_congested,
8423         .change_consistency_policy = raid5_change_consistency_policy,
8424 };
8425 static struct md_personality raid5_personality =
8426 {
8427         .name           = "raid5",
8428         .level          = 5,
8429         .owner          = THIS_MODULE,
8430         .make_request   = raid5_make_request,
8431         .run            = raid5_run,
8432         .start          = raid5_start,
8433         .free           = raid5_free,
8434         .status         = raid5_status,
8435         .error_handler  = raid5_error,
8436         .hot_add_disk   = raid5_add_disk,
8437         .hot_remove_disk= raid5_remove_disk,
8438         .spare_active   = raid5_spare_active,
8439         .sync_request   = raid5_sync_request,
8440         .resize         = raid5_resize,
8441         .size           = raid5_size,
8442         .check_reshape  = raid5_check_reshape,
8443         .start_reshape  = raid5_start_reshape,
8444         .finish_reshape = raid5_finish_reshape,
8445         .quiesce        = raid5_quiesce,
8446         .takeover       = raid5_takeover,
8447         .congested      = raid5_congested,
8448         .change_consistency_policy = raid5_change_consistency_policy,
8449 };
8450
8451 static struct md_personality raid4_personality =
8452 {
8453         .name           = "raid4",
8454         .level          = 4,
8455         .owner          = THIS_MODULE,
8456         .make_request   = raid5_make_request,
8457         .run            = raid5_run,
8458         .start          = raid5_start,
8459         .free           = raid5_free,
8460         .status         = raid5_status,
8461         .error_handler  = raid5_error,
8462         .hot_add_disk   = raid5_add_disk,
8463         .hot_remove_disk= raid5_remove_disk,
8464         .spare_active   = raid5_spare_active,
8465         .sync_request   = raid5_sync_request,
8466         .resize         = raid5_resize,
8467         .size           = raid5_size,
8468         .check_reshape  = raid5_check_reshape,
8469         .start_reshape  = raid5_start_reshape,
8470         .finish_reshape = raid5_finish_reshape,
8471         .quiesce        = raid5_quiesce,
8472         .takeover       = raid4_takeover,
8473         .congested      = raid5_congested,
8474         .change_consistency_policy = raid5_change_consistency_policy,
8475 };
8476
8477 static int __init raid5_init(void)
8478 {
8479         int ret;
8480
8481         raid5_wq = alloc_workqueue("raid5wq",
8482                 WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE|WQ_SYSFS, 0);
8483         if (!raid5_wq)
8484                 return -ENOMEM;
8485
8486         ret = cpuhp_setup_state_multi(CPUHP_MD_RAID5_PREPARE,
8487                                       "md/raid5:prepare",
8488                                       raid456_cpu_up_prepare,
8489                                       raid456_cpu_dead);
8490         if (ret) {
8491                 destroy_workqueue(raid5_wq);
8492                 return ret;
8493         }
8494         register_md_personality(&raid6_personality);
8495         register_md_personality(&raid5_personality);
8496         register_md_personality(&raid4_personality);
8497         return 0;
8498 }
8499
8500 static void raid5_exit(void)
8501 {
8502         unregister_md_personality(&raid6_personality);
8503         unregister_md_personality(&raid5_personality);
8504         unregister_md_personality(&raid4_personality);
8505         cpuhp_remove_multi_state(CPUHP_MD_RAID5_PREPARE);
8506         destroy_workqueue(raid5_wq);
8507 }
8508
8509 module_init(raid5_init);
8510 module_exit(raid5_exit);
8511 MODULE_LICENSE("GPL");
8512 MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
8513 MODULE_ALIAS("md-personality-4"); /* RAID5 */
8514 MODULE_ALIAS("md-raid5");
8515 MODULE_ALIAS("md-raid4");
8516 MODULE_ALIAS("md-level-5");
8517 MODULE_ALIAS("md-level-4");
8518 MODULE_ALIAS("md-personality-8"); /* RAID6 */
8519 MODULE_ALIAS("md-raid6");
8520 MODULE_ALIAS("md-level-6");
8521
8522 /* This used to be two separate modules, they were: */
8523 MODULE_ALIAS("raid5");
8524 MODULE_ALIAS("raid6");