drivers/md/raid10.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * raid10.c : Multiple Devices driver for Linux
   4  *
   5  * Copyright (C) 2000-2004 Neil Brown
   6  *
   7  * RAID-10 support for md.
   8  *
   9  * Base on code in raid1.c.  See raid1.c for further copyright information.
  10  */
  11
  12 #include <linux/slab.h>
  13 #include <linux/delay.h>
  14 #include <linux/blkdev.h>
  15 #include <linux/module.h>
  16 #include <linux/seq_file.h>
  17 #include <linux/ratelimit.h>
  18 #include <linux/kthread.h>
  19 #include <linux/raid/md_p.h>
  20 #include <trace/events/block.h>
  21 #include "md.h"
  22 #include "raid10.h"
  23 #include "raid0.h"
  24 #include "md-bitmap.h"
  25
  26 /*
  27  * RAID10 provides a combination of RAID0 and RAID1 functionality.
  28  * The layout of data is defined by
  29  *    chunk_size
  30  *    raid_disks
  31  *    near_copies (stored in low byte of layout)
  32  *    far_copies (stored in second byte of layout)
  33  *    far_offset (stored in bit 16 of layout )
  34  *    use_far_sets (stored in bit 17 of layout )
  35  *    use_far_sets_bugfixed (stored in bit 18 of layout )
  36  *
  37  * The data to be stored is divided into chunks using chunksize.  Each device
  38  * is divided into far_copies sections.   In each section, chunks are laid out
  39  * in a style similar to raid0, but near_copies copies of each chunk is stored
  40  * (each on a different drive).  The starting device for each section is offset
  41  * near_copies from the starting device of the previous section.  Thus there
  42  * are (near_copies * far_copies) of each chunk, and each is on a different
  43  * drive.  near_copies and far_copies must be at least one, and their product
  44  * is at most raid_disks.
  45  *
  46  * If far_offset is true, then the far_copies are handled a bit differently.
  47  * The copies are still in different stripes, but instead of being very far
  48  * apart on disk, there are adjacent stripes.
  49  *
  50  * The far and offset algorithms are handled slightly differently if
  51  * 'use_far_sets' is true.  In this case, the array's devices are grouped into
  52  * sets that are (near_copies * far_copies) in size.  The far copied stripes
  53  * are still shifted by 'near_copies' devices, but this shifting stays confined
  54  * to the set rather than the entire array.  This is done to improve the number
  55  * of device combinations that can fail without causing the array to fail.
  56  * Example 'far' algorithm w/o 'use_far_sets' (each letter represents a chunk
  57  * on a device):
  58  *    A B C D    A B C D E
  59  *      ...         ...
  60  *    D A B C    E A B C D
  61  * Example 'far' algorithm w/ 'use_far_sets' enabled (sets illustrated w/ []'s):
  62  *    [A B] [C D]    [A B] [C D E]
  63  *    |...| |...|    |...| | ... |
  64  *    [B A] [D C]    [B A] [E C D]
  65  */
  66
  67 static void allow_barrier(struct r10conf *conf);
  68 static void lower_barrier(struct r10conf *conf);
  69 static int _enough(struct r10conf *conf, int previous, int ignore);
  70 static int enough(struct r10conf *conf, int ignore);
  71 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr,
  72                                 int *skipped);
  73 static void reshape_request_write(struct mddev *mddev, struct r10bio *r10_bio);
  74 static void end_reshape_write(struct bio *bio);
  75 static void end_reshape(struct r10conf *conf);
  76
  77 #define raid10_log(md, fmt, args...)                            \
  78         do { if ((md)->queue) blk_add_trace_msg((md)->queue, "raid10 " fmt, ##args); } while (0)
  79
  80 #include "raid1-10.c"
  81
  82 /*
  83  * for resync bio, r10bio pointer can be retrieved from the per-bio
  84  * 'struct resync_pages'.
  85  */
  86 static inline struct r10bio *get_resync_r10bio(struct bio *bio)
  87 {
  88         return get_resync_pages(bio)->raid_bio;
  89 }
  90
  91 static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data)
  92 {
  93         struct r10conf *conf = data;
  94         int size = offsetof(struct r10bio, devs[conf->geo.raid_disks]);
  95
  96         /* allocate a r10bio with room for raid_disks entries in the
  97          * bios array */
  98         return kzalloc(size, gfp_flags);
  99 }
 100
 101 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
 102 /* amount of memory to reserve for resync requests */
 103 #define RESYNC_WINDOW (1024*1024)
 104 /* maximum number of concurrent requests, memory permitting */
 105 #define RESYNC_DEPTH (32*1024*1024/RESYNC_BLOCK_SIZE)
 106 #define CLUSTER_RESYNC_WINDOW (32 * RESYNC_WINDOW)
 107 #define CLUSTER_RESYNC_WINDOW_SECTORS (CLUSTER_RESYNC_WINDOW >> 9)
 108
 109 /*
 110  * When performing a resync, we need to read and compare, so
 111  * we need as many pages are there are copies.
 112  * When performing a recovery, we need 2 bios, one for read,
 113  * one for write (we recover only one drive per r10buf)
 114  *
 115  */
 116 static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
 117 {
 118         struct r10conf *conf = data;
 119         struct r10bio *r10_bio;
 120         struct bio *bio;
 121         int j;
 122         int nalloc, nalloc_rp;
 123         struct resync_pages *rps;
 124
 125         r10_bio = r10bio_pool_alloc(gfp_flags, conf);
 126         if (!r10_bio)
 127                 return NULL;
 128
 129         if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery) ||
 130             test_bit(MD_RECOVERY_RESHAPE, &conf->mddev->recovery))
 131                 nalloc = conf->copies; /* resync */
 132         else
 133                 nalloc = 2; /* recovery */
 134
 135         /* allocate once for all bios */
 136         if (!conf->have_replacement)
 137                 nalloc_rp = nalloc;
 138         else
 139                 nalloc_rp = nalloc * 2;
 140         rps = kmalloc_array(nalloc_rp, sizeof(struct resync_pages), gfp_flags);
 141         if (!rps)
 142                 goto out_free_r10bio;
 143
 144         /*
 145          * Allocate bios.
 146          */
 147         for (j = nalloc ; j-- ; ) {
 148                 bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
 149                 if (!bio)
 150                         goto out_free_bio;
 151                 r10_bio->devs[j].bio = bio;
 152                 if (!conf->have_replacement)
 153                         continue;
 154                 bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
 155                 if (!bio)
 156                         goto out_free_bio;
 157                 r10_bio->devs[j].repl_bio = bio;
 158         }
 159         /*
 160          * Allocate RESYNC_PAGES data pages and attach them
 161          * where needed.
 162          */
 163         for (j = 0; j < nalloc; j++) {
 164                 struct bio *rbio = r10_bio->devs[j].repl_bio;
 165                 struct resync_pages *rp, *rp_repl;
 166
 167                 rp = &rps[j];
 168                 if (rbio)
 169                         rp_repl = &rps[nalloc + j];
 170
 171                 bio = r10_bio->devs[j].bio;
 172
 173                 if (!j || test_bit(MD_RECOVERY_SYNC,
 174                                    &conf->mddev->recovery)) {
 175                         if (resync_alloc_pages(rp, gfp_flags))
 176                                 goto out_free_pages;
 177                 } else {
 178                         memcpy(rp, &rps[0], sizeof(*rp));
 179                         resync_get_all_pages(rp);
 180                 }
 181
 182                 rp->raid_bio = r10_bio;
 183                 bio->bi_private = rp;
 184                 if (rbio) {
 185                         memcpy(rp_repl, rp, sizeof(*rp));
 186                         rbio->bi_private = rp_repl;
 187                 }
 188         }
 189
 190         return r10_bio;
 191
 192 out_free_pages:
 193         while (--j >= 0)
 194                 resync_free_pages(&rps[j]);
 195
 196         j = 0;
 197 out_free_bio:
 198         for ( ; j < nalloc; j++) {
 199                 if (r10_bio->devs[j].bio)
 200                         bio_put(r10_bio->devs[j].bio);
 201                 if (r10_bio->devs[j].repl_bio)
 202                         bio_put(r10_bio->devs[j].repl_bio);
 203         }
 204         kfree(rps);
 205 out_free_r10bio:
 206         rbio_pool_free(r10_bio, conf);
 207         return NULL;
 208 }
 209
 210 static void r10buf_pool_free(void *__r10_bio, void *data)
 211 {
 212         struct r10conf *conf = data;
 213         struct r10bio *r10bio = __r10_bio;
 214         int j;
 215         struct resync_pages *rp = NULL;
 216
 217         for (j = conf->copies; j--; ) {
 218                 struct bio *bio = r10bio->devs[j].bio;
 219
 220                 if (bio) {
 221                         rp = get_resync_pages(bio);
 222                         resync_free_pages(rp);
 223                         bio_put(bio);
 224                 }
 225
 226                 bio = r10bio->devs[j].repl_bio;
 227                 if (bio)
 228                         bio_put(bio);
 229         }
 230
 231         /* resync pages array stored in the 1st bio's .bi_private */
 232         kfree(rp);
 233
 234         rbio_pool_free(r10bio, conf);
 235 }
 236
 237 static void put_all_bios(struct r10conf *conf, struct r10bio *r10_bio)
 238 {
 239         int i;
 240
 241         for (i = 0; i < conf->geo.raid_disks; i++) {
 242                 struct bio **bio = & r10_bio->devs[i].bio;
 243                 if (!BIO_SPECIAL(*bio))
 244                         bio_put(*bio);
 245                 *bio = NULL;
 246                 bio = &r10_bio->devs[i].repl_bio;
 247                 if (r10_bio->read_slot < 0 && !BIO_SPECIAL(*bio))
 248                         bio_put(*bio);
 249                 *bio = NULL;
 250         }
 251 }
 252
 253 static void free_r10bio(struct r10bio *r10_bio)
 254 {
 255         struct r10conf *conf = r10_bio->mddev->private;
 256
 257         put_all_bios(conf, r10_bio);
 258         mempool_free(r10_bio, &conf->r10bio_pool);
 259 }
 260
 261 static void put_buf(struct r10bio *r10_bio)
 262 {
 263         struct r10conf *conf = r10_bio->mddev->private;
 264
 265         mempool_free(r10_bio, &conf->r10buf_pool);
 266
 267         lower_barrier(conf);
 268 }
 269
 270 static void reschedule_retry(struct r10bio *r10_bio)
 271 {
 272         unsigned long flags;
 273         struct mddev *mddev = r10_bio->mddev;
 274         struct r10conf *conf = mddev->private;
 275
 276         spin_lock_irqsave(&conf->device_lock, flags);
 277         list_add(&r10_bio->retry_list, &conf->retry_list);
 278         conf->nr_queued ++;
 279         spin_unlock_irqrestore(&conf->device_lock, flags);
 280
 281         /* wake up frozen array... */
 282         wake_up(&conf->wait_barrier);
 283
 284         md_wakeup_thread(mddev->thread);
 285 }
 286
 287 /*
 288  * raid_end_bio_io() is called when we have finished servicing a mirrored
 289  * operation and are ready to return a success/failure code to the buffer
 290  * cache layer.
 291  */
 292 static void raid_end_bio_io(struct r10bio *r10_bio)
 293 {
 294         struct bio *bio = r10_bio->master_bio;
 295         struct r10conf *conf = r10_bio->mddev->private;
 296
 297         if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
 298                 bio->bi_status = BLK_STS_IOERR;
 299
 300         bio_endio(bio);
 301         /*
 302          * Wake up any possible resync thread that waits for the device
 303          * to go idle.
 304          */
 305         allow_barrier(conf);
 306
 307         free_r10bio(r10_bio);
 308 }
 309
 310 /*
 311  * Update disk head position estimator based on IRQ completion info.
 312  */
 313 static inline void update_head_pos(int slot, struct r10bio *r10_bio)
 314 {
 315         struct r10conf *conf = r10_bio->mddev->private;
 316
 317         conf->mirrors[r10_bio->devs[slot].devnum].head_position =
 318                 r10_bio->devs[slot].addr + (r10_bio->sectors);
 319 }
 320
 321 /*
 322  * Find the disk number which triggered given bio
 323  */
 324 static int find_bio_disk(struct r10conf *conf, struct r10bio *r10_bio,
 325                          struct bio *bio, int *slotp, int *replp)
 326 {
 327         int slot;
 328         int repl = 0;
 329
 330         for (slot = 0; slot < conf->geo.raid_disks; slot++) {
 331                 if (r10_bio->devs[slot].bio == bio)
 332                         break;
 333                 if (r10_bio->devs[slot].repl_bio == bio) {
 334                         repl = 1;
 335                         break;
 336                 }
 337         }
 338
 339         update_head_pos(slot, r10_bio);
 340
 341         if (slotp)
 342                 *slotp = slot;
 343         if (replp)
 344                 *replp = repl;
 345         return r10_bio->devs[slot].devnum;
 346 }
 347
 348 static void raid10_end_read_request(struct bio *bio)
 349 {
 350         int uptodate = !bio->bi_status;
 351         struct r10bio *r10_bio = bio->bi_private;
 352         int slot;
 353         struct md_rdev *rdev;
 354         struct r10conf *conf = r10_bio->mddev->private;
 355
 356         slot = r10_bio->read_slot;
 357         rdev = r10_bio->devs[slot].rdev;
 358         /*
 359          * this branch is our 'one mirror IO has finished' event handler:
 360          */
 361         update_head_pos(slot, r10_bio);
 362
 363         if (uptodate) {
 364                 /*
 365                  * Set R10BIO_Uptodate in our master bio, so that
 366                  * we will return a good error code to the higher
 367                  * levels even if IO on some other mirrored buffer fails.
 368                  *
 369                  * The 'master' represents the composite IO operation to
 370                  * user-side. So if something waits for IO, then it will
 371                  * wait for the 'master' bio.
 372                  */
 373                 set_bit(R10BIO_Uptodate, &r10_bio->state);
 374         } else {
 375                 /* If all other devices that store this block have
 376                  * failed, we want to return the error upwards rather
 377                  * than fail the last device.  Here we redefine
 378                  * "uptodate" to mean "Don't want to retry"
 379                  */
 380                 if (!_enough(conf, test_bit(R10BIO_Previous, &r10_bio->state),
 381                              rdev->raid_disk))
 382                         uptodate = 1;
 383         }
 384         if (uptodate) {
 385                 raid_end_bio_io(r10_bio);
 386                 rdev_dec_pending(rdev, conf->mddev);
 387         } else {
 388                 /*
 389                  * oops, read error - keep the refcount on the rdev
 390                  */
 391                 char b[BDEVNAME_SIZE];
 392                 pr_err_ratelimited("md/raid10:%s: %s: rescheduling sector %llu\n",
 393                                    mdname(conf->mddev),
 394                                    bdevname(rdev->bdev, b),
 395                                    (unsigned long long)r10_bio->sector);
 396                 set_bit(R10BIO_ReadError, &r10_bio->state);
 397                 reschedule_retry(r10_bio);
 398         }
 399 }
 400
 401 static void close_write(struct r10bio *r10_bio)
 402 {
 403         /* clear the bitmap if all writes complete successfully */
 404         md_bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector,
 405                            r10_bio->sectors,
 406                            !test_bit(R10BIO_Degraded, &r10_bio->state),
 407                            0);
 408         md_write_end(r10_bio->mddev);
 409 }
 410
 411 static void one_write_done(struct r10bio *r10_bio)
 412 {
 413         if (atomic_dec_and_test(&r10_bio->remaining)) {
 414                 if (test_bit(R10BIO_WriteError, &r10_bio->state))
 415                         reschedule_retry(r10_bio);
 416                 else {
 417                         close_write(r10_bio);
 418                         if (test_bit(R10BIO_MadeGood, &r10_bio->state))
 419                                 reschedule_retry(r10_bio);
 420                         else
 421                                 raid_end_bio_io(r10_bio);
 422                 }
 423         }
 424 }
 425
 426 static void raid10_end_write_request(struct bio *bio)
 427 {
 428         struct r10bio *r10_bio = bio->bi_private;
 429         int dev;
 430         int dec_rdev = 1;
 431         struct r10conf *conf = r10_bio->mddev->private;
 432         int slot, repl;
 433         struct md_rdev *rdev = NULL;
 434         struct bio *to_put = NULL;
 435         bool discard_error;
 436
 437         discard_error = bio->bi_status && bio_op(bio) == REQ_OP_DISCARD;
 438
 439         dev = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
 440
 441         if (repl)
 442                 rdev = conf->mirrors[dev].replacement;
 443         if (!rdev) {
 444                 smp_rmb();
 445                 repl = 0;
 446                 rdev = conf->mirrors[dev].rdev;
 447         }
 448         /*
 449          * this branch is our 'one mirror IO has finished' event handler:
 450          */
 451         if (bio->bi_status && !discard_error) {
 452                 if (repl)
 453                         /* Never record new bad blocks to replacement,
 454                          * just fail it.
 455                          */
 456                         md_error(rdev->mddev, rdev);
 457                 else {
 458                         set_bit(WriteErrorSeen, &rdev->flags);
 459                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
 460                                 set_bit(MD_RECOVERY_NEEDED,
 461                                         &rdev->mddev->recovery);
 462
 463                         dec_rdev = 0;
 464                         if (test_bit(FailFast, &rdev->flags) &&
 465                             (bio->bi_opf & MD_FAILFAST)) {
 466                                 md_error(rdev->mddev, rdev);
 467                         }
 468
 469                         /*
 470                          * When the device is faulty, it is not necessary to
 471                          * handle write error.
 472                          * For failfast, this is the only remaining device,
 473                          * We need to retry the write without FailFast.
 474                          */
 475                         if (!test_bit(Faulty, &rdev->flags))
 476                                 set_bit(R10BIO_WriteError, &r10_bio->state);
 477                         else {
 478                                 r10_bio->devs[slot].bio = NULL;
 479                                 to_put = bio;
 480                                 dec_rdev = 1;
 481                         }
 482                 }
 483         } else {
 484                 /*
 485                  * Set R10BIO_Uptodate in our master bio, so that
 486                  * we will return a good error code for to the higher
 487                  * levels even if IO on some other mirrored buffer fails.
 488                  *
 489                  * The 'master' represents the composite IO operation to
 490                  * user-side. So if something waits for IO, then it will
 491                  * wait for the 'master' bio.
 492                  */
 493                 sector_t first_bad;
 494                 int bad_sectors;
 495
 496                 /*
 497                  * Do not set R10BIO_Uptodate if the current device is
 498                  * rebuilding or Faulty. This is because we cannot use
 499                  * such device for properly reading the data back (we could
 500                  * potentially use it, if the current write would have felt
 501                  * before rdev->recovery_offset, but for simplicity we don't
 502                  * check this here.
 503                  */
 504                 if (test_bit(In_sync, &rdev->flags) &&
 505                     !test_bit(Faulty, &rdev->flags))
 506                         set_bit(R10BIO_Uptodate, &r10_bio->state);
 507
 508                 /* Maybe we can clear some bad blocks. */
 509                 if (is_badblock(rdev,
 510                                 r10_bio->devs[slot].addr,
 511                                 r10_bio->sectors,
 512                                 &first_bad, &bad_sectors) && !discard_error) {
 513                         bio_put(bio);
 514                         if (repl)
 515                                 r10_bio->devs[slot].repl_bio = IO_MADE_GOOD;
 516                         else
 517                                 r10_bio->devs[slot].bio = IO_MADE_GOOD;
 518                         dec_rdev = 0;
 519                         set_bit(R10BIO_MadeGood, &r10_bio->state);
 520                 }
 521         }
 522
 523         /*
 524          *
 525          * Let's see if all mirrored write operations have finished
 526          * already.
 527          */
 528         one_write_done(r10_bio);
 529         if (dec_rdev)
 530                 rdev_dec_pending(rdev, conf->mddev);
 531         if (to_put)
 532                 bio_put(to_put);
 533 }
 534
 535 /*
 536  * RAID10 layout manager
 537  * As well as the chunksize and raid_disks count, there are two
 538  * parameters: near_copies and far_copies.
 539  * near_copies * far_copies must be <= raid_disks.
 540  * Normally one of these will be 1.
 541  * If both are 1, we get raid0.
 542  * If near_copies == raid_disks, we get raid1.
 543  *
 544  * Chunks are laid out in raid0 style with near_copies copies of the
 545  * first chunk, followed by near_copies copies of the next chunk and
 546  * so on.
 547  * If far_copies > 1, then after 1/far_copies of the array has been assigned
 548  * as described above, we start again with a device offset of near_copies.
 549  * So we effectively have another copy of the whole array further down all
 550  * the drives, but with blocks on different drives.
 551  * With this layout, and block is never stored twice on the one device.
 552  *
 553  * raid10_find_phys finds the sector offset of a given virtual sector
 554  * on each device that it is on.
 555  *
 556  * raid10_find_virt does the reverse mapping, from a device and a
 557  * sector offset to a virtual address
 558  */
 559
 560 static void __raid10_find_phys(struct geom *geo, struct r10bio *r10bio)
 561 {
 562         int n,f;
 563         sector_t sector;
 564         sector_t chunk;
 565         sector_t stripe;
 566         int dev;
 567         int slot = 0;
 568         int last_far_set_start, last_far_set_size;
 569
 570         last_far_set_start = (geo->raid_disks / geo->far_set_size) - 1;
 571         last_far_set_start *= geo->far_set_size;
 572
 573         last_far_set_size = geo->far_set_size;
 574         last_far_set_size += (geo->raid_disks % geo->far_set_size);
 575
 576         /* now calculate first sector/dev */
 577         chunk = r10bio->sector >> geo->chunk_shift;
 578         sector = r10bio->sector & geo->chunk_mask;
 579
 580         chunk *= geo->near_copies;
 581         stripe = chunk;
 582         dev = sector_div(stripe, geo->raid_disks);
 583         if (geo->far_offset)
 584                 stripe *= geo->far_copies;
 585
 586         sector += stripe << geo->chunk_shift;
 587
 588         /* and calculate all the others */
 589         for (n = 0; n < geo->near_copies; n++) {
 590                 int d = dev;
 591                 int set;
 592                 sector_t s = sector;
 593                 r10bio->devs[slot].devnum = d;
 594                 r10bio->devs[slot].addr = s;
 595                 slot++;
 596
 597                 for (f = 1; f < geo->far_copies; f++) {
 598                         set = d / geo->far_set_size;
 599                         d += geo->near_copies;
 600
 601                         if ((geo->raid_disks % geo->far_set_size) &&
 602                             (d > last_far_set_start)) {
 603                                 d -= last_far_set_start;
 604                                 d %= last_far_set_size;
 605                                 d += last_far_set_start;
 606                         } else {
 607                                 d %= geo->far_set_size;
 608                                 d += geo->far_set_size * set;
 609                         }
 610                         s += geo->stride;
 611                         r10bio->devs[slot].devnum = d;
 612                         r10bio->devs[slot].addr = s;
 613                         slot++;
 614                 }
 615                 dev++;
 616                 if (dev >= geo->raid_disks) {
 617                         dev = 0;
 618                         sector += (geo->chunk_mask + 1);
 619                 }
 620         }
 621 }
 622
 623 static void raid10_find_phys(struct r10conf *conf, struct r10bio *r10bio)
 624 {
 625         struct geom *geo = &conf->geo;
 626
 627         if (conf->reshape_progress != MaxSector &&
 628             ((r10bio->sector >= conf->reshape_progress) !=
 629              conf->mddev->reshape_backwards)) {
 630                 set_bit(R10BIO_Previous, &r10bio->state);
 631                 geo = &conf->prev;
 632         } else
 633                 clear_bit(R10BIO_Previous, &r10bio->state);
 634
 635         __raid10_find_phys(geo, r10bio);
 636 }
 637
 638 static sector_t raid10_find_virt(struct r10conf *conf, sector_t sector, int dev)
 639 {
 640         sector_t offset, chunk, vchunk;
 641         /* Never use conf->prev as this is only called during resync
 642          * or recovery, so reshape isn't happening
 643          */
 644         struct geom *geo = &conf->geo;
 645         int far_set_start = (dev / geo->far_set_size) * geo->far_set_size;
 646         int far_set_size = geo->far_set_size;
 647         int last_far_set_start;
 648
 649         if (geo->raid_disks % geo->far_set_size) {
 650                 last_far_set_start = (geo->raid_disks / geo->far_set_size) - 1;
 651                 last_far_set_start *= geo->far_set_size;
 652
 653                 if (dev >= last_far_set_start) {
 654                         far_set_size = geo->far_set_size;
 655                         far_set_size += (geo->raid_disks % geo->far_set_size);
 656                         far_set_start = last_far_set_start;
 657                 }
 658         }
 659
 660         offset = sector & geo->chunk_mask;
 661         if (geo->far_offset) {
 662                 int fc;
 663                 chunk = sector >> geo->chunk_shift;
 664                 fc = sector_div(chunk, geo->far_copies);
 665                 dev -= fc * geo->near_copies;
 666                 if (dev < far_set_start)
 667                         dev += far_set_size;
 668         } else {
 669                 while (sector >= geo->stride) {
 670                         sector -= geo->stride;
 671                         if (dev < (geo->near_copies + far_set_start))
 672                                 dev += far_set_size - geo->near_copies;
 673                         else
 674                                 dev -= geo->near_copies;
 675                 }
 676                 chunk = sector >> geo->chunk_shift;
 677         }
 678         vchunk = chunk * geo->raid_disks + dev;
 679         sector_div(vchunk, geo->near_copies);
 680         return (vchunk << geo->chunk_shift) + offset;
 681 }
 682
 683 /*
 684  * This routine returns the disk from which the requested read should
 685  * be done. There is a per-array 'next expected sequential IO' sector
 686  * number - if this matches on the next IO then we use the last disk.
 687  * There is also a per-disk 'last know head position' sector that is
 688  * maintained from IRQ contexts, both the normal and the resync IO
 689  * completion handlers update this position correctly. If there is no
 690  * perfect sequential match then we pick the disk whose head is closest.
 691  *
 692  * If there are 2 mirrors in the same 2 devices, performance degrades
 693  * because position is mirror, not device based.
 694  *
 695  * The rdev for the device selected will have nr_pending incremented.
 696  */
 697
 698 /*
 699  * FIXME: possibly should rethink readbalancing and do it differently
 700  * depending on near_copies / far_copies geometry.
 701  */
 702 static struct md_rdev *read_balance(struct r10conf *conf,
 703                                     struct r10bio *r10_bio,
 704                                     int *max_sectors)
 705 {
 706         const sector_t this_sector = r10_bio->sector;
 707         int disk, slot;
 708         int sectors = r10_bio->sectors;
 709         int best_good_sectors;
 710         sector_t new_distance, best_dist;
 711         struct md_rdev *best_dist_rdev, *best_pending_rdev, *rdev = NULL;
 712         int do_balance;
 713         int best_dist_slot, best_pending_slot;
 714         bool has_nonrot_disk = false;
 715         unsigned int min_pending;
 716         struct geom *geo = &conf->geo;
 717
 718         raid10_find_phys(conf, r10_bio);
 719         rcu_read_lock();
 720         best_dist_slot = -1;
 721         min_pending = UINT_MAX;
 722         best_dist_rdev = NULL;
 723         best_pending_rdev = NULL;
 724         best_dist = MaxSector;
 725         best_good_sectors = 0;
 726         do_balance = 1;
 727         clear_bit(R10BIO_FailFast, &r10_bio->state);
 728         /*
 729          * Check if we can balance. We can balance on the whole
 730          * device if no resync is going on (recovery is ok), or below
 731          * the resync window. We take the first readable disk when
 732          * above the resync window.
 733          */
 734         if ((conf->mddev->recovery_cp < MaxSector
 735              && (this_sector + sectors >= conf->next_resync)) ||
 736             (mddev_is_clustered(conf->mddev) &&
 737              md_cluster_ops->area_resyncing(conf->mddev, READ, this_sector,
 738                                             this_sector + sectors)))
 739                 do_balance = 0;
 740
 741         for (slot = 0; slot < conf->copies ; slot++) {
 742                 sector_t first_bad;
 743                 int bad_sectors;
 744                 sector_t dev_sector;
 745                 unsigned int pending;
 746                 bool nonrot;
 747
 748                 if (r10_bio->devs[slot].bio == IO_BLOCKED)
 749                         continue;
 750                 disk = r10_bio->devs[slot].devnum;
 751                 rdev = rcu_dereference(conf->mirrors[disk].replacement);
 752                 if (rdev == NULL || test_bit(Faulty, &rdev->flags) ||
 753                     r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
 754                         rdev = rcu_dereference(conf->mirrors[disk].rdev);
 755                 if (rdev == NULL ||
 756                     test_bit(Faulty, &rdev->flags))
 757                         continue;
 758                 if (!test_bit(In_sync, &rdev->flags) &&
 759                     r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
 760                         continue;
 761
 762                 dev_sector = r10_bio->devs[slot].addr;
 763                 if (is_badblock(rdev, dev_sector, sectors,
 764                                 &first_bad, &bad_sectors)) {
 765                         if (best_dist < MaxSector)
 766                                 /* Already have a better slot */
 767                                 continue;
 768                         if (first_bad <= dev_sector) {
 769                                 /* Cannot read here.  If this is the
 770                                  * 'primary' device, then we must not read
 771                                  * beyond 'bad_sectors' from another device.
 772                                  */
 773                                 bad_sectors -= (dev_sector - first_bad);
 774                                 if (!do_balance && sectors > bad_sectors)
 775                                         sectors = bad_sectors;
 776                                 if (best_good_sectors > sectors)
 777                                         best_good_sectors = sectors;
 778                         } else {
 779                                 sector_t good_sectors =
 780                                         first_bad - dev_sector;
 781                                 if (good_sectors > best_good_sectors) {
 782                                         best_good_sectors = good_sectors;
 783                                         best_dist_slot = slot;
 784                                         best_dist_rdev = rdev;
 785                                 }
 786                                 if (!do_balance)
 787                                         /* Must read from here */
 788                                         break;
 789                         }
 790                         continue;
 791                 } else
 792                         best_good_sectors = sectors;
 793
 794                 if (!do_balance)
 795                         break;
 796
 797                 nonrot = blk_queue_nonrot(bdev_get_queue(rdev->bdev));
 798                 has_nonrot_disk |= nonrot;
 799                 pending = atomic_read(&rdev->nr_pending);
 800                 if (min_pending > pending && nonrot) {
 801                         min_pending = pending;
 802                         best_pending_slot = slot;
 803                         best_pending_rdev = rdev;
 804                 }
 805
 806                 if (best_dist_slot >= 0)
 807                         /* At least 2 disks to choose from so failfast is OK */
 808                         set_bit(R10BIO_FailFast, &r10_bio->state);
 809                 /* This optimisation is debatable, and completely destroys
 810                  * sequential read speed for 'far copies' arrays.  So only
 811                  * keep it for 'near' arrays, and review those later.
 812                  */
 813                 if (geo->near_copies > 1 && !pending)
 814                         new_distance = 0;
 815
 816                 /* for far > 1 always use the lowest address */
 817                 else if (geo->far_copies > 1)
 818                         new_distance = r10_bio->devs[slot].addr;
 819                 else
 820                         new_distance = abs(r10_bio->devs[slot].addr -
 821                                            conf->mirrors[disk].head_position);
 822
 823                 if (new_distance < best_dist) {
 824                         best_dist = new_distance;
 825                         best_dist_slot = slot;
 826                         best_dist_rdev = rdev;
 827                 }
 828         }
 829         if (slot >= conf->copies) {
 830                 if (has_nonrot_disk) {
 831                         slot = best_pending_slot;
 832                         rdev = best_pending_rdev;
 833                 } else {
 834                         slot = best_dist_slot;
 835                         rdev = best_dist_rdev;
 836                 }
 837         }
 838
 839         if (slot >= 0) {
 840                 atomic_inc(&rdev->nr_pending);
 841                 r10_bio->read_slot = slot;
 842         } else
 843                 rdev = NULL;
 844         rcu_read_unlock();
 845         *max_sectors = best_good_sectors;
 846
 847         return rdev;
 848 }
 849
 850 static void flush_pending_writes(struct r10conf *conf)
 851 {
 852         /* Any writes that have been queued but are awaiting
 853          * bitmap updates get flushed here.
 854          */
 855         spin_lock_irq(&conf->device_lock);
 856
 857         if (conf->pending_bio_list.head) {
 858                 struct blk_plug plug;
 859                 struct bio *bio;
 860
 861                 bio = bio_list_get(&conf->pending_bio_list);
 862                 conf->pending_count = 0;
 863                 spin_unlock_irq(&conf->device_lock);
 864
 865                 /*
 866                  * As this is called in a wait_event() loop (see freeze_array),
 867                  * current->state might be TASK_UNINTERRUPTIBLE which will
 868                  * cause a warning when we prepare to wait again.  As it is
 869                  * rare that this path is taken, it is perfectly safe to force
 870                  * us to go around the wait_event() loop again, so the warning
 871                  * is a false-positive. Silence the warning by resetting
 872                  * thread state
 873                  */
 874                 __set_current_state(TASK_RUNNING);
 875
 876                 blk_start_plug(&plug);
 877                 /* flush any pending bitmap writes to disk
 878                  * before proceeding w/ I/O */
 879                 md_bitmap_unplug(conf->mddev->bitmap);
 880                 wake_up(&conf->wait_barrier);
 881
 882                 while (bio) { /* submit pending writes */
 883                         struct bio *next = bio->bi_next;
 884                         struct md_rdev *rdev = (void*)bio->bi_disk;
 885                         bio->bi_next = NULL;
 886                         bio_set_dev(bio, rdev->bdev);
 887                         if (test_bit(Faulty, &rdev->flags)) {
 888                                 bio_io_error(bio);
 889                         } else if (unlikely((bio_op(bio) ==  REQ_OP_DISCARD) &&
 890                                             !blk_queue_discard(bio->bi_disk->queue)))
 891                                 /* Just ignore it */
 892                                 bio_endio(bio);
 893                         else
 894                                 submit_bio_noacct(bio);
 895                         bio = next;
 896                 }
 897                 blk_finish_plug(&plug);
 898         } else
 899                 spin_unlock_irq(&conf->device_lock);
 900 }
 901
 902 /* Barriers....
 903  * Sometimes we need to suspend IO while we do something else,
 904  * either some resync/recovery, or reconfigure the array.
 905  * To do this we raise a 'barrier'.
 906  * The 'barrier' is a counter that can be raised multiple times
 907  * to count how many activities are happening which preclude
 908  * normal IO.
 909  * We can only raise the barrier if there is no pending IO.
 910  * i.e. if nr_pending == 0.
 911  * We choose only to raise the barrier if no-one is waiting for the
 912  * barrier to go down.  This means that as soon as an IO request
 913  * is ready, no other operations which require a barrier will start
 914  * until the IO request has had a chance.
 915  *
 916  * So: regular IO calls 'wait_barrier'.  When that returns there
 917  *    is no backgroup IO happening,  It must arrange to call
 918  *    allow_barrier when it has finished its IO.
 919  * backgroup IO calls must call raise_barrier.  Once that returns
 920  *    there is no normal IO happeing.  It must arrange to call
 921  *    lower_barrier when the particular background IO completes.
 922  */
 923
 924 static void raise_barrier(struct r10conf *conf, int force)
 925 {
 926         BUG_ON(force && !conf->barrier);
 927         spin_lock_irq(&conf->resync_lock);
 928
 929         /* Wait until no block IO is waiting (unless 'force') */
 930         wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting,
 931                             conf->resync_lock);
 932
 933         /* block any new IO from starting */
 934         conf->barrier++;
 935
 936         /* Now wait for all pending IO to complete */
 937         wait_event_lock_irq(conf->wait_barrier,
 938                             !atomic_read(&conf->nr_pending) && conf->barrier < RESYNC_DEPTH,
 939                             conf->resync_lock);
 940
 941         spin_unlock_irq(&conf->resync_lock);
 942 }
 943
 944 static void lower_barrier(struct r10conf *conf)
 945 {
 946         unsigned long flags;
 947         spin_lock_irqsave(&conf->resync_lock, flags);
 948         conf->barrier--;
 949         spin_unlock_irqrestore(&conf->resync_lock, flags);
 950         wake_up(&conf->wait_barrier);
 951 }
 952
 953 static void wait_barrier(struct r10conf *conf)
 954 {
 955         spin_lock_irq(&conf->resync_lock);
 956         if (conf->barrier) {
 957                 struct bio_list *bio_list = current->bio_list;
 958                 conf->nr_waiting++;
 959                 /* Wait for the barrier to drop.
 960                  * However if there are already pending
 961                  * requests (preventing the barrier from
 962                  * rising completely), and the
 963                  * pre-process bio queue isn't empty,
 964                  * then don't wait, as we need to empty
 965                  * that queue to get the nr_pending
 966                  * count down.
 967                  */
 968                 raid10_log(conf->mddev, "wait barrier");
 969                 wait_event_lock_irq(conf->wait_barrier,
 970                                     !conf->barrier ||
 971                                     (atomic_read(&conf->nr_pending) &&
 972                                      bio_list &&
 973                                      (!bio_list_empty(&bio_list[0]) ||
 974                                       !bio_list_empty(&bio_list[1]))) ||
 975                                      /* move on if recovery thread is
 976                                       * blocked by us
 977                                       */
 978                                      (conf->mddev->thread->tsk == current &&
 979                                       test_bit(MD_RECOVERY_RUNNING,
 980                                                &conf->mddev->recovery) &&
 981                                       conf->nr_queued > 0),
 982                                     conf->resync_lock);
 983                 conf->nr_waiting--;
 984                 if (!conf->nr_waiting)
 985                         wake_up(&conf->wait_barrier);
 986         }
 987         atomic_inc(&conf->nr_pending);
 988         spin_unlock_irq(&conf->resync_lock);
 989 }
 990
 991 static void allow_barrier(struct r10conf *conf)
 992 {
 993         if ((atomic_dec_and_test(&conf->nr_pending)) ||
 994                         (conf->array_freeze_pending))
 995                 wake_up(&conf->wait_barrier);
 996 }
 997
 998 static void freeze_array(struct r10conf *conf, int extra)
 999 {
1000         /* stop syncio and normal IO and wait for everything to
1001          * go quiet.
1002          * We increment barrier and nr_waiting, and then
1003          * wait until nr_pending match nr_queued+extra
1004          * This is called in the context of one normal IO request
1005          * that has failed. Thus any sync request that might be pending
1006          * will be blocked by nr_pending, and we need to wait for
1007          * pending IO requests to complete or be queued for re-try.
1008          * Thus the number queued (nr_queued) plus this request (extra)
1009          * must match the number of pending IOs (nr_pending) before
1010          * we continue.
1011          */
1012         spin_lock_irq(&conf->resync_lock);
1013         conf->array_freeze_pending++;
1014         conf->barrier++;
1015         conf->nr_waiting++;
1016         wait_event_lock_irq_cmd(conf->wait_barrier,
1017                                 atomic_read(&conf->nr_pending) == conf->nr_queued+extra,
1018                                 conf->resync_lock,
1019                                 flush_pending_writes(conf));
1020
1021         conf->array_freeze_pending--;
1022         spin_unlock_irq(&conf->resync_lock);
1023 }
1024
1025 static void unfreeze_array(struct r10conf *conf)
1026 {
1027         /* reverse the effect of the freeze */
1028         spin_lock_irq(&conf->resync_lock);
1029         conf->barrier--;
1030         conf->nr_waiting--;
1031         wake_up(&conf->wait_barrier);
1032         spin_unlock_irq(&conf->resync_lock);
1033 }
1034
1035 static sector_t choose_data_offset(struct r10bio *r10_bio,
1036                                    struct md_rdev *rdev)
1037 {
1038         if (!test_bit(MD_RECOVERY_RESHAPE, &rdev->mddev->recovery) ||
1039             test_bit(R10BIO_Previous, &r10_bio->state))
1040                 return rdev->data_offset;
1041         else
1042                 return rdev->new_data_offset;
1043 }
1044
1045 struct raid10_plug_cb {
1046         struct blk_plug_cb      cb;
1047         struct bio_list         pending;
1048         int                     pending_cnt;
1049 };
1050
1051 static void raid10_unplug(struct blk_plug_cb *cb, bool from_schedule)
1052 {
1053         struct raid10_plug_cb *plug = container_of(cb, struct raid10_plug_cb,
1054                                                    cb);
1055         struct mddev *mddev = plug->cb.data;
1056         struct r10conf *conf = mddev->private;
1057         struct bio *bio;
1058
1059         if (from_schedule || current->bio_list) {
1060                 spin_lock_irq(&conf->device_lock);
1061                 bio_list_merge(&conf->pending_bio_list, &plug->pending);
1062                 conf->pending_count += plug->pending_cnt;
1063                 spin_unlock_irq(&conf->device_lock);
1064                 wake_up(&conf->wait_barrier);
1065                 md_wakeup_thread(mddev->thread);
1066                 kfree(plug);
1067                 return;
1068         }
1069
1070         /* we aren't scheduling, so we can do the write-out directly. */
1071         bio = bio_list_get(&plug->pending);
1072         md_bitmap_unplug(mddev->bitmap);
1073         wake_up(&conf->wait_barrier);
1074
1075         while (bio) { /* submit pending writes */
1076                 struct bio *next = bio->bi_next;
1077                 struct md_rdev *rdev = (void*)bio->bi_disk;
1078                 bio->bi_next = NULL;
1079                 bio_set_dev(bio, rdev->bdev);
1080                 if (test_bit(Faulty, &rdev->flags)) {
1081                         bio_io_error(bio);
1082                 } else if (unlikely((bio_op(bio) ==  REQ_OP_DISCARD) &&
1083                                     !blk_queue_discard(bio->bi_disk->queue)))
1084                         /* Just ignore it */
1085                         bio_endio(bio);
1086                 else
1087                         submit_bio_noacct(bio);
1088                 bio = next;
1089         }
1090         kfree(plug);
1091 }
1092
1093 /*
1094  * 1. Register the new request and wait if the reconstruction thread has put
1095  * up a bar for new requests. Continue immediately if no resync is active
1096  * currently.
1097  * 2. If IO spans the reshape position.  Need to wait for reshape to pass.
1098  */
1099 static void regular_request_wait(struct mddev *mddev, struct r10conf *conf,
1100                                  struct bio *bio, sector_t sectors)
1101 {
1102         wait_barrier(conf);
1103         while (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
1104             bio->bi_iter.bi_sector < conf->reshape_progress &&
1105             bio->bi_iter.bi_sector + sectors > conf->reshape_progress) {
1106                 raid10_log(conf->mddev, "wait reshape");
1107                 allow_barrier(conf);
1108                 wait_event(conf->wait_barrier,
1109                            conf->reshape_progress <= bio->bi_iter.bi_sector ||
1110                            conf->reshape_progress >= bio->bi_iter.bi_sector +
1111                            sectors);
1112                 wait_barrier(conf);
1113         }
1114 }
1115
1116 static void raid10_read_request(struct mddev *mddev, struct bio *bio,
1117                                 struct r10bio *r10_bio)
1118 {
1119         struct r10conf *conf = mddev->private;
1120         struct bio *read_bio;
1121         const int op = bio_op(bio);
1122         const unsigned long do_sync = (bio->bi_opf & REQ_SYNC);
1123         int max_sectors;
1124         struct md_rdev *rdev;
1125         char b[BDEVNAME_SIZE];
1126         int slot = r10_bio->read_slot;
1127         struct md_rdev *err_rdev = NULL;
1128         gfp_t gfp = GFP_NOIO;
1129
1130         if (r10_bio->devs[slot].rdev) {
1131                 /*
1132                  * This is an error retry, but we cannot
1133                  * safely dereference the rdev in the r10_bio,
1134                  * we must use the one in conf.
1135                  * If it has already been disconnected (unlikely)
1136                  * we lose the device name in error messages.
1137                  */
1138                 int disk;
1139                 /*
1140                  * As we are blocking raid10, it is a little safer to
1141                  * use __GFP_HIGH.
1142                  */
1143                 gfp = GFP_NOIO | __GFP_HIGH;
1144
1145                 rcu_read_lock();
1146                 disk = r10_bio->devs[slot].devnum;
1147                 err_rdev = rcu_dereference(conf->mirrors[disk].rdev);
1148                 if (err_rdev)
1149                         bdevname(err_rdev->bdev, b);
1150                 else {
1151                         strcpy(b, "???");
1152                         /* This never gets dereferenced */
1153                         err_rdev = r10_bio->devs[slot].rdev;
1154                 }
1155                 rcu_read_unlock();
1156         }
1157
1158         regular_request_wait(mddev, conf, bio, r10_bio->sectors);
1159         rdev = read_balance(conf, r10_bio, &max_sectors);
1160         if (!rdev) {
1161                 if (err_rdev) {
1162                         pr_crit_ratelimited("md/raid10:%s: %s: unrecoverable I/O read error for block %llu\n",
1163                                             mdname(mddev), b,
1164                                             (unsigned long long)r10_bio->sector);
1165                 }
1166                 raid_end_bio_io(r10_bio);
1167                 return;
1168         }
1169         if (err_rdev)
1170                 pr_err_ratelimited("md/raid10:%s: %s: redirecting sector %llu to another mirror\n",
1171                                    mdname(mddev),
1172                                    bdevname(rdev->bdev, b),
1173                                    (unsigned long long)r10_bio->sector);
1174         if (max_sectors < bio_sectors(bio)) {
1175                 struct bio *split = bio_split(bio, max_sectors,
1176                                               gfp, &conf->bio_split);
1177                 bio_chain(split, bio);
1178                 allow_barrier(conf);
1179                 submit_bio_noacct(bio);
1180                 wait_barrier(conf);
1181                 bio = split;
1182                 r10_bio->master_bio = bio;
1183                 r10_bio->sectors = max_sectors;
1184         }
1185         slot = r10_bio->read_slot;
1186
1187         read_bio = bio_clone_fast(bio, gfp, &mddev->bio_set);
1188
1189         r10_bio->devs[slot].bio = read_bio;
1190         r10_bio->devs[slot].rdev = rdev;
1191
1192         read_bio->bi_iter.bi_sector = r10_bio->devs[slot].addr +
1193                 choose_data_offset(r10_bio, rdev);
1194         bio_set_dev(read_bio, rdev->bdev);
1195         read_bio->bi_end_io = raid10_end_read_request;
1196         bio_set_op_attrs(read_bio, op, do_sync);
1197         if (test_bit(FailFast, &rdev->flags) &&
1198             test_bit(R10BIO_FailFast, &r10_bio->state))
1199                 read_bio->bi_opf |= MD_FAILFAST;
1200         read_bio->bi_private = r10_bio;
1201
1202         if (mddev->gendisk)
1203                 trace_block_bio_remap(read_bio->bi_disk->queue,
1204                                       read_bio, disk_devt(mddev->gendisk),
1205                                       r10_bio->sector);
1206         submit_bio_noacct(read_bio);
1207         return;
1208 }
1209
1210 static void raid10_write_one_disk(struct mddev *mddev, struct r10bio *r10_bio,
1211                                   struct bio *bio, bool replacement,
1212                                   int n_copy)
1213 {
1214         const int op = bio_op(bio);
1215         const unsigned long do_sync = (bio->bi_opf & REQ_SYNC);
1216         const unsigned long do_fua = (bio->bi_opf & REQ_FUA);
1217         unsigned long flags;
1218         struct blk_plug_cb *cb;
1219         struct raid10_plug_cb *plug = NULL;
1220         struct r10conf *conf = mddev->private;
1221         struct md_rdev *rdev;
1222         int devnum = r10_bio->devs[n_copy].devnum;
1223         struct bio *mbio;
1224
1225         if (replacement) {
1226                 rdev = conf->mirrors[devnum].replacement;
1227                 if (rdev == NULL) {
1228                         /* Replacement just got moved to main 'rdev' */
1229                         smp_mb();
1230                         rdev = conf->mirrors[devnum].rdev;
1231                 }
1232         } else
1233                 rdev = conf->mirrors[devnum].rdev;
1234
1235         mbio = bio_clone_fast(bio, GFP_NOIO, &mddev->bio_set);
1236         if (replacement)
1237                 r10_bio->devs[n_copy].repl_bio = mbio;
1238         else
1239                 r10_bio->devs[n_copy].bio = mbio;
1240
1241         mbio->bi_iter.bi_sector = (r10_bio->devs[n_copy].addr +
1242                                    choose_data_offset(r10_bio, rdev));
1243         bio_set_dev(mbio, rdev->bdev);
1244         mbio->bi_end_io = raid10_end_write_request;
1245         bio_set_op_attrs(mbio, op, do_sync | do_fua);
1246         if (!replacement && test_bit(FailFast,
1247                                      &conf->mirrors[devnum].rdev->flags)
1248                          && enough(conf, devnum))
1249                 mbio->bi_opf |= MD_FAILFAST;
1250         mbio->bi_private = r10_bio;
1251
1252         if (conf->mddev->gendisk)
1253                 trace_block_bio_remap(mbio->bi_disk->queue,
1254                                       mbio, disk_devt(conf->mddev->gendisk),
1255                                       r10_bio->sector);
1256         /* flush_pending_writes() needs access to the rdev so...*/
1257         mbio->bi_disk = (void *)rdev;
1258
1259         atomic_inc(&r10_bio->remaining);
1260
1261         cb = blk_check_plugged(raid10_unplug, mddev, sizeof(*plug));
1262         if (cb)
1263                 plug = container_of(cb, struct raid10_plug_cb, cb);
1264         else
1265                 plug = NULL;
1266         if (plug) {
1267                 bio_list_add(&plug->pending, mbio);
1268                 plug->pending_cnt++;
1269         } else {
1270                 spin_lock_irqsave(&conf->device_lock, flags);
1271                 bio_list_add(&conf->pending_bio_list, mbio);
1272                 conf->pending_count++;
1273                 spin_unlock_irqrestore(&conf->device_lock, flags);
1274                 md_wakeup_thread(mddev->thread);
1275         }
1276 }
1277
1278 static void wait_blocked_dev(struct mddev *mddev, struct r10bio *r10_bio)
1279 {
1280         int i;
1281         struct r10conf *conf = mddev->private;
1282         struct md_rdev *blocked_rdev;
1283
1284 retry_wait:
1285         blocked_rdev = NULL;
1286         rcu_read_lock();
1287         for (i = 0; i < conf->copies; i++) {
1288                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1289                 struct md_rdev *rrdev = rcu_dereference(
1290                         conf->mirrors[i].replacement);
1291                 if (rdev == rrdev)
1292                         rrdev = NULL;
1293                 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
1294                         atomic_inc(&rdev->nr_pending);
1295                         blocked_rdev = rdev;
1296                         break;
1297                 }
1298                 if (rrdev && unlikely(test_bit(Blocked, &rrdev->flags))) {
1299                         atomic_inc(&rrdev->nr_pending);
1300                         blocked_rdev = rrdev;
1301                         break;
1302                 }
1303
1304                 if (rdev && test_bit(WriteErrorSeen, &rdev->flags)) {
1305                         sector_t first_bad;
1306                         sector_t dev_sector = r10_bio->devs[i].addr;
1307                         int bad_sectors;
1308                         int is_bad;
1309
1310                         /* Discard request doesn't care the write result
1311                          * so it doesn't need to wait blocked disk here.
1312                          */
1313                         if (!r10_bio->sectors)
1314                                 continue;
1315
1316                         is_bad = is_badblock(rdev, dev_sector, r10_bio->sectors,
1317                                              &first_bad, &bad_sectors);
1318                         if (is_bad < 0) {
1319                                 /* Mustn't write here until the bad block
1320                                  * is acknowledged
1321                                  */
1322                                 atomic_inc(&rdev->nr_pending);
1323                                 set_bit(BlockedBadBlocks, &rdev->flags);
1324                                 blocked_rdev = rdev;
1325                                 break;
1326                         }
1327                 }
1328         }
1329         rcu_read_unlock();
1330
1331         if (unlikely(blocked_rdev)) {
1332                 /* Have to wait for this device to get unblocked, then retry */
1333                 allow_barrier(conf);
1334                 raid10_log(conf->mddev, "%s wait rdev %d blocked",
1335                                 __func__, blocked_rdev->raid_disk);
1336                 md_wait_for_blocked_rdev(blocked_rdev, mddev);
1337                 wait_barrier(conf);
1338                 goto retry_wait;
1339         }
1340 }
1341
1342 static void raid10_write_request(struct mddev *mddev, struct bio *bio,
1343                                  struct r10bio *r10_bio)
1344 {
1345         struct r10conf *conf = mddev->private;
1346         int i;
1347         sector_t sectors;
1348         int max_sectors;
1349
1350         if ((mddev_is_clustered(mddev) &&
1351              md_cluster_ops->area_resyncing(mddev, WRITE,
1352                                             bio->bi_iter.bi_sector,
1353                                             bio_end_sector(bio)))) {
1354                 DEFINE_WAIT(w);
1355                 for (;;) {
1356                         prepare_to_wait(&conf->wait_barrier,
1357                                         &w, TASK_IDLE);
1358                         if (!md_cluster_ops->area_resyncing(mddev, WRITE,
1359                                  bio->bi_iter.bi_sector, bio_end_sector(bio)))
1360                                 break;
1361                         schedule();
1362                 }
1363                 finish_wait(&conf->wait_barrier, &w);
1364         }
1365
1366         sectors = r10_bio->sectors;
1367         regular_request_wait(mddev, conf, bio, sectors);
1368         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
1369             (mddev->reshape_backwards
1370              ? (bio->bi_iter.bi_sector < conf->reshape_safe &&
1371                 bio->bi_iter.bi_sector + sectors > conf->reshape_progress)
1372              : (bio->bi_iter.bi_sector + sectors > conf->reshape_safe &&
1373                 bio->bi_iter.bi_sector < conf->reshape_progress))) {
1374                 /* Need to update reshape_position in metadata */
1375                 mddev->reshape_position = conf->reshape_progress;
1376                 set_mask_bits(&mddev->sb_flags, 0,
1377                               BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
1378                 md_wakeup_thread(mddev->thread);
1379                 raid10_log(conf->mddev, "wait reshape metadata");
1380                 wait_event(mddev->sb_wait,
1381                            !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags));
1382
1383                 conf->reshape_safe = mddev->reshape_position;
1384         }
1385
1386         if (conf->pending_count >= max_queued_requests) {
1387                 md_wakeup_thread(mddev->thread);
1388                 raid10_log(mddev, "wait queued");
1389                 wait_event(conf->wait_barrier,
1390                            conf->pending_count < max_queued_requests);
1391         }
1392         /* first select target devices under rcu_lock and
1393          * inc refcount on their rdev.  Record them by setting
1394          * bios[x] to bio
1395          * If there are known/acknowledged bad blocks on any device
1396          * on which we have seen a write error, we want to avoid
1397          * writing to those blocks.  This potentially requires several
1398          * writes to write around the bad blocks.  Each set of writes
1399          * gets its own r10_bio with a set of bios attached.
1400          */
1401
1402         r10_bio->read_slot = -1; /* make sure repl_bio gets freed */
1403         raid10_find_phys(conf, r10_bio);
1404
1405         wait_blocked_dev(mddev, r10_bio);
1406
1407         rcu_read_lock();
1408         max_sectors = r10_bio->sectors;
1409
1410         for (i = 0;  i < conf->copies; i++) {
1411                 int d = r10_bio->devs[i].devnum;
1412                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[d].rdev);
1413                 struct md_rdev *rrdev = rcu_dereference(
1414                         conf->mirrors[d].replacement);
1415                 if (rdev == rrdev)
1416                         rrdev = NULL;
1417                 if (rdev && (test_bit(Faulty, &rdev->flags)))
1418                         rdev = NULL;
1419                 if (rrdev && (test_bit(Faulty, &rrdev->flags)))
1420                         rrdev = NULL;
1421
1422                 r10_bio->devs[i].bio = NULL;
1423                 r10_bio->devs[i].repl_bio = NULL;
1424
1425                 if (!rdev && !rrdev) {
1426                         set_bit(R10BIO_Degraded, &r10_bio->state);
1427                         continue;
1428                 }
1429                 if (rdev && test_bit(WriteErrorSeen, &rdev->flags)) {
1430                         sector_t first_bad;
1431                         sector_t dev_sector = r10_bio->devs[i].addr;
1432                         int bad_sectors;
1433                         int is_bad;
1434
1435                         is_bad = is_badblock(rdev, dev_sector, max_sectors,
1436                                              &first_bad, &bad_sectors);
1437                         if (is_bad && first_bad <= dev_sector) {
1438                                 /* Cannot write here at all */
1439                                 bad_sectors -= (dev_sector - first_bad);
1440                                 if (bad_sectors < max_sectors)
1441                                         /* Mustn't write more than bad_sectors
1442                                          * to other devices yet
1443                                          */
1444                                         max_sectors = bad_sectors;
1445                                 /* We don't set R10BIO_Degraded as that
1446                                  * only applies if the disk is missing,
1447                                  * so it might be re-added, and we want to
1448                                  * know to recover this chunk.
1449                                  * In this case the device is here, and the
1450                                  * fact that this chunk is not in-sync is
1451                                  * recorded in the bad block log.
1452                                  */
1453                                 continue;
1454                         }
1455                         if (is_bad) {
1456                                 int good_sectors = first_bad - dev_sector;
1457                                 if (good_sectors < max_sectors)
1458                                         max_sectors = good_sectors;
1459                         }
1460                 }
1461                 if (rdev) {
1462                         r10_bio->devs[i].bio = bio;
1463                         atomic_inc(&rdev->nr_pending);
1464                 }
1465                 if (rrdev) {
1466                         r10_bio->devs[i].repl_bio = bio;
1467                         atomic_inc(&rrdev->nr_pending);
1468                 }
1469         }
1470         rcu_read_unlock();
1471
1472         if (max_sectors < r10_bio->sectors)
1473                 r10_bio->sectors = max_sectors;
1474
1475         if (r10_bio->sectors < bio_sectors(bio)) {
1476                 struct bio *split = bio_split(bio, r10_bio->sectors,
1477                                               GFP_NOIO, &conf->bio_split);
1478                 bio_chain(split, bio);
1479                 allow_barrier(conf);
1480                 submit_bio_noacct(bio);
1481                 wait_barrier(conf);
1482                 bio = split;
1483                 r10_bio->master_bio = bio;
1484         }
1485
1486         atomic_set(&r10_bio->remaining, 1);
1487         md_bitmap_startwrite(mddev->bitmap, r10_bio->sector, r10_bio->sectors, 0);
1488
1489         for (i = 0; i < conf->copies; i++) {
1490                 if (r10_bio->devs[i].bio)
1491                         raid10_write_one_disk(mddev, r10_bio, bio, false, i);
1492                 if (r10_bio->devs[i].repl_bio)
1493                         raid10_write_one_disk(mddev, r10_bio, bio, true, i);
1494         }
1495         one_write_done(r10_bio);
1496 }
1497
1498 static void __make_request(struct mddev *mddev, struct bio *bio, int sectors)
1499 {
1500         struct r10conf *conf = mddev->private;
1501         struct r10bio *r10_bio;
1502
1503         r10_bio = mempool_alloc(&conf->r10bio_pool, GFP_NOIO);
1504
1505         r10_bio->master_bio = bio;
1506         r10_bio->sectors = sectors;
1507
1508         r10_bio->mddev = mddev;
1509         r10_bio->sector = bio->bi_iter.bi_sector;
1510         r10_bio->state = 0;
1511         memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) * conf->geo.raid_disks);
1512
1513         if (bio_data_dir(bio) == READ)
1514                 raid10_read_request(mddev, bio, r10_bio);
1515         else
1516                 raid10_write_request(mddev, bio, r10_bio);
1517 }
1518
1519 static struct bio *raid10_split_bio(struct r10conf *conf,
1520                         struct bio *bio, sector_t sectors, bool want_first)
1521 {
1522         struct bio *split;
1523
1524         split = bio_split(bio, sectors, GFP_NOIO, &conf->bio_split);
1525         bio_chain(split, bio);
1526         allow_barrier(conf);
1527         if (want_first) {
1528                 submit_bio_noacct(bio);
1529                 bio = split;
1530         } else
1531                 submit_bio_noacct(split);
1532         wait_barrier(conf);
1533
1534         return bio;
1535 }
1536
1537 static void raid_end_discard_bio(struct r10bio *r10bio)
1538 {
1539         struct r10conf *conf = r10bio->mddev->private;
1540         struct r10bio *first_r10bio;
1541
1542         while (atomic_dec_and_test(&r10bio->remaining)) {
1543
1544                 allow_barrier(conf);
1545
1546                 if (!test_bit(R10BIO_Discard, &r10bio->state)) {
1547                         first_r10bio = (struct r10bio *)r10bio->master_bio;
1548                         free_r10bio(r10bio);
1549                         r10bio = first_r10bio;
1550                 } else {
1551                         md_write_end(r10bio->mddev);
1552                         bio_endio(r10bio->master_bio);
1553                         free_r10bio(r10bio);
1554                         break;
1555                 }
1556         }
1557 }
1558
1559 static void raid10_end_discard_request(struct bio *bio)
1560 {
1561         struct r10bio *r10_bio = bio->bi_private;
1562         struct r10conf *conf = r10_bio->mddev->private;
1563         struct md_rdev *rdev = NULL;
1564         int dev;
1565         int slot, repl;
1566
1567         /*
1568          * We don't care the return value of discard bio
1569          */
1570         if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
1571                 set_bit(R10BIO_Uptodate, &r10_bio->state);
1572
1573         dev = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
1574         if (repl)
1575                 rdev = conf->mirrors[dev].replacement;
1576         if (!rdev) {
1577                 /* raid10_remove_disk uses smp_mb to make sure rdev is set to
1578                  * replacement before setting replacement to NULL. It can read
1579                  * rdev first without barrier protect even replacment is NULL
1580                  */
1581                 smp_rmb();
1582                 rdev = conf->mirrors[dev].rdev;
1583         }
1584
1585         raid_end_discard_bio(r10_bio);
1586         rdev_dec_pending(rdev, conf->mddev);
1587 }
1588
1589 /* There are some limitations to handle discard bio
1590  * 1st, the discard size is bigger than stripe_size*2.
1591  * 2st, if the discard bio spans reshape progress, we use the old way to
1592  * handle discard bio
1593  */
1594 static int raid10_handle_discard(struct mddev *mddev, struct bio *bio)
1595 {
1596         struct r10conf *conf = mddev->private;
1597         struct geom *geo = &conf->geo;
1598         struct r10bio *r10_bio, *first_r10bio;
1599         int far_copies = geo->far_copies;
1600         bool first_copy = true;
1601
1602         int disk;
1603         sector_t chunk;
1604         unsigned int stripe_size;
1605         sector_t split_size;
1606
1607         sector_t bio_start, bio_end;
1608         sector_t first_stripe_index, last_stripe_index;
1609         sector_t start_disk_offset;
1610         unsigned int start_disk_index;
1611         sector_t end_disk_offset;
1612         unsigned int end_disk_index;
1613         unsigned int remainder;
1614
1615         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
1616                 return -EAGAIN;
1617
1618         wait_barrier(conf);
1619
1620         /* Check reshape again to avoid reshape happens after checking
1621          * MD_RECOVERY_RESHAPE and before wait_barrier
1622          */
1623         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
1624                 goto out;
1625
1626         stripe_size = geo->raid_disks << geo->chunk_shift;
1627         bio_start = bio->bi_iter.bi_sector;
1628         bio_end = bio_end_sector(bio);
1629
1630         /* Maybe one discard bio is smaller than strip size or across one stripe
1631          * and discard region is larger than one stripe size. For far offset layout,
1632          * if the discard region is not aligned with stripe size, there is hole
1633          * when we submit discard bio to member disk. For simplicity, we only
1634          * handle discard bio which discard region is bigger than stripe_size*2
1635          */
1636         if (bio_sectors(bio) < stripe_size*2)
1637                 goto out;
1638
1639         /* For far and far offset layout, if bio is not aligned with stripe size,
1640          * it splits the part that is not aligned with strip size.
1641          */
1642         div_u64_rem(bio_start, stripe_size, &remainder);
1643         if ((far_copies > 1) && remainder) {
1644                 split_size = stripe_size - remainder;
1645                 bio = raid10_split_bio(conf, bio, split_size, false);
1646         }
1647         div_u64_rem(bio_end, stripe_size, &remainder);
1648         if ((far_copies > 1) && remainder) {
1649                 split_size = bio_sectors(bio) - remainder;
1650                 bio = raid10_split_bio(conf, bio, split_size, true);
1651         }
1652
1653         bio_start = bio->bi_iter.bi_sector;
1654         bio_end = bio_end_sector(bio);
1655
1656         /* raid10 uses chunk as the unit to store data. It's similar like raid0.
1657          * One stripe contains the chunks from all member disk (one chunk from
1658          * one disk at the same HBA address). For layout detail, see 'man md 4'
1659          */
1660         chunk = bio_start >> geo->chunk_shift;
1661         chunk *= geo->near_copies;
1662         first_stripe_index = chunk;
1663         start_disk_index = sector_div(first_stripe_index, geo->raid_disks);
1664         if (geo->far_offset)
1665                 first_stripe_index *= geo->far_copies;
1666         start_disk_offset = (bio_start & geo->chunk_mask) +
1667                                 (first_stripe_index << geo->chunk_shift);
1668
1669         chunk = bio_end >> geo->chunk_shift;
1670         chunk *= geo->near_copies;
1671         last_stripe_index = chunk;
1672         end_disk_index = sector_div(last_stripe_index, geo->raid_disks);
1673         if (geo->far_offset)
1674                 last_stripe_index *= geo->far_copies;
1675         end_disk_offset = (bio_end & geo->chunk_mask) +
1676                                 (last_stripe_index << geo->chunk_shift);
1677
1678 retry_discard:
1679         r10_bio = mempool_alloc(&conf->r10bio_pool, GFP_NOIO);
1680         r10_bio->mddev = mddev;
1681         r10_bio->state = 0;
1682         r10_bio->sectors = 0;
1683         memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) * geo->raid_disks);
1684         wait_blocked_dev(mddev, r10_bio);
1685
1686         /* For far layout it needs more than one r10bio to cover all regions.
1687          * Inspired by raid10_sync_request, we can use the first r10bio->master_bio
1688          * to record the discard bio. Other r10bio->master_bio record the first
1689          * r10bio. The first r10bio only release after all other r10bios finish.
1690          * The discard bio returns only first r10bio finishes
1691          */
1692         if (first_copy) {
1693                 r10_bio->master_bio = bio;
1694                 set_bit(R10BIO_Discard, &r10_bio->state);
1695                 first_copy = false;
1696                 first_r10bio = r10_bio;
1697         } else
1698                 r10_bio->master_bio = (struct bio *)first_r10bio;
1699
1700         rcu_read_lock();
1701         for (disk = 0; disk < geo->raid_disks; disk++) {
1702                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[disk].rdev);
1703                 struct md_rdev *rrdev = rcu_dereference(
1704                         conf->mirrors[disk].replacement);
1705
1706                 r10_bio->devs[disk].bio = NULL;
1707                 r10_bio->devs[disk].repl_bio = NULL;
1708
1709                 if (rdev && (test_bit(Faulty, &rdev->flags)))
1710                         rdev = NULL;
1711                 if (rrdev && (test_bit(Faulty, &rrdev->flags)))
1712                         rrdev = NULL;
1713                 if (!rdev && !rrdev)
1714                         continue;
1715
1716                 if (rdev) {
1717                         r10_bio->devs[disk].bio = bio;
1718                         atomic_inc(&rdev->nr_pending);
1719                 }
1720                 if (rrdev) {
1721                         r10_bio->devs[disk].repl_bio = bio;
1722                         atomic_inc(&rrdev->nr_pending);
1723                 }
1724         }
1725         rcu_read_unlock();
1726
1727         atomic_set(&r10_bio->remaining, 1);
1728         for (disk = 0; disk < geo->raid_disks; disk++) {
1729                 sector_t dev_start, dev_end;
1730                 struct bio *mbio, *rbio = NULL;
1731                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[disk].rdev);
1732                 struct md_rdev *rrdev = rcu_dereference(
1733                         conf->mirrors[disk].replacement);
1734
1735                 /*
1736                  * Now start to calculate the start and end address for each disk.
1737                  * The space between dev_start and dev_end is the discard region.
1738                  *
1739                  * For dev_start, it needs to consider three conditions:
1740                  * 1st, the disk is before start_disk, you can imagine the disk in
1741                  * the next stripe. So the dev_start is the start address of next
1742                  * stripe.
1743                  * 2st, the disk is after start_disk, it means the disk is at the
1744                  * same stripe of first disk
1745                  * 3st, the first disk itself, we can use start_disk_offset directly
1746                  */
1747                 if (disk < start_disk_index)
1748                         dev_start = (first_stripe_index + 1) * mddev->chunk_sectors;
1749                 else if (disk > start_disk_index)
1750                         dev_start = first_stripe_index * mddev->chunk_sectors;
1751                 else
1752                         dev_start = start_disk_offset;
1753
1754                 if (disk < end_disk_index)
1755                         dev_end = (last_stripe_index + 1) * mddev->chunk_sectors;
1756                 else if (disk > end_disk_index)
1757                         dev_end = last_stripe_index * mddev->chunk_sectors;
1758                 else
1759                         dev_end = end_disk_offset;
1760
1761                 /* It only handles discard bio which size is >= stripe size, so
1762                  * dev_end > dev_start all the time
1763                  */
1764                 if (r10_bio->devs[disk].bio) {
1765                         mbio = bio_clone_fast(bio, GFP_NOIO, &mddev->bio_set);
1766                         mbio->bi_end_io = raid10_end_discard_request;
1767                         mbio->bi_private = r10_bio;
1768                         r10_bio->devs[disk].bio = mbio;
1769                         r10_bio->devs[disk].devnum = disk;
1770                         atomic_inc(&r10_bio->remaining);
1771                         md_submit_discard_bio(mddev, rdev, mbio,
1772                                         dev_start + choose_data_offset(r10_bio, rdev),
1773                                         dev_end - dev_start);
1774                         bio_endio(mbio);
1775                 }
1776                 if (r10_bio->devs[disk].repl_bio) {
1777                         rbio = bio_clone_fast(bio, GFP_NOIO, &mddev->bio_set);
1778                         rbio->bi_end_io = raid10_end_discard_request;
1779                         rbio->bi_private = r10_bio;
1780                         r10_bio->devs[disk].repl_bio = rbio;
1781                         r10_bio->devs[disk].devnum = disk;
1782                         atomic_inc(&r10_bio->remaining);
1783                         md_submit_discard_bio(mddev, rrdev, rbio,
1784                                         dev_start + choose_data_offset(r10_bio, rrdev),
1785                                         dev_end - dev_start);
1786                         bio_endio(rbio);
1787                 }
1788         }
1789
1790         if (!geo->far_offset && --far_copies) {
1791                 first_stripe_index += geo->stride >> geo->chunk_shift;
1792                 start_disk_offset += geo->stride;
1793                 last_stripe_index += geo->stride >> geo->chunk_shift;
1794                 end_disk_offset += geo->stride;
1795                 atomic_inc(&first_r10bio->remaining);
1796                 raid_end_discard_bio(r10_bio);
1797                 wait_barrier(conf);
1798                 goto retry_discard;
1799         }
1800
1801         raid_end_discard_bio(r10_bio);
1802
1803         return 0;
1804 out:
1805         allow_barrier(conf);
1806         return -EAGAIN;
1807 }
1808
1809 static bool raid10_make_request(struct mddev *mddev, struct bio *bio)
1810 {
1811         struct r10conf *conf = mddev->private;
1812         sector_t chunk_mask = (conf->geo.chunk_mask & conf->prev.chunk_mask);
1813         int chunk_sects = chunk_mask + 1;
1814         int sectors = bio_sectors(bio);
1815
1816         if (unlikely(bio->bi_opf & REQ_PREFLUSH)
1817             && md_flush_request(mddev, bio))
1818                 return true;
1819
1820         if (!md_write_start(mddev, bio))
1821                 return false;
1822
1823         if (unlikely(bio_op(bio) == REQ_OP_DISCARD))
1824                 if (!raid10_handle_discard(mddev, bio))
1825                         return true;
1826
1827         /*
1828          * If this request crosses a chunk boundary, we need to split
1829          * it.
1830          */
1831         if (unlikely((bio->bi_iter.bi_sector & chunk_mask) +
1832                      sectors > chunk_sects
1833                      && (conf->geo.near_copies < conf->geo.raid_disks
1834                          || conf->prev.near_copies <
1835                          conf->prev.raid_disks)))
1836                 sectors = chunk_sects -
1837                         (bio->bi_iter.bi_sector &
1838                          (chunk_sects - 1));
1839         __make_request(mddev, bio, sectors);
1840
1841         /* In case raid10d snuck in to freeze_array */
1842         wake_up(&conf->wait_barrier);
1843         return true;
1844 }
1845
1846 static void raid10_status(struct seq_file *seq, struct mddev *mddev)
1847 {
1848         struct r10conf *conf = mddev->private;
1849         int i;
1850
1851         if (conf->geo.near_copies < conf->geo.raid_disks)
1852                 seq_printf(seq, " %dK chunks", mddev->chunk_sectors / 2);
1853         if (conf->geo.near_copies > 1)
1854                 seq_printf(seq, " %d near-copies", conf->geo.near_copies);
1855         if (conf->geo.far_copies > 1) {
1856                 if (conf->geo.far_offset)
1857                         seq_printf(seq, " %d offset-copies", conf->geo.far_copies);
1858                 else
1859                         seq_printf(seq, " %d far-copies", conf->geo.far_copies);
1860                 if (conf->geo.far_set_size != conf->geo.raid_disks)
1861                         seq_printf(seq, " %d devices per set", conf->geo.far_set_size);
1862         }
1863         seq_printf(seq, " [%d/%d] [", conf->geo.raid_disks,
1864                                         conf->geo.raid_disks - mddev->degraded);
1865         rcu_read_lock();
1866         for (i = 0; i < conf->geo.raid_disks; i++) {
1867                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1868                 seq_printf(seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1869         }
1870         rcu_read_unlock();
1871         seq_printf(seq, "]");
1872 }
1873
1874 /* check if there are enough drives for
1875  * every block to appear on atleast one.
1876  * Don't consider the device numbered 'ignore'
1877  * as we might be about to remove it.
1878  */
1879 static int _enough(struct r10conf *conf, int previous, int ignore)
1880 {
1881         int first = 0;
1882         int has_enough = 0;
1883         int disks, ncopies;
1884         if (previous) {
1885                 disks = conf->prev.raid_disks;
1886                 ncopies = conf->prev.near_copies;
1887         } else {
1888                 disks = conf->geo.raid_disks;
1889                 ncopies = conf->geo.near_copies;
1890         }
1891
1892         rcu_read_lock();
1893         do {
1894                 int n = conf->copies;
1895                 int cnt = 0;
1896                 int this = first;
1897                 while (n--) {
1898                         struct md_rdev *rdev;
1899                         if (this != ignore &&
1900                             (rdev = rcu_dereference(conf->mirrors[this].rdev)) &&
1901                             test_bit(In_sync, &rdev->flags))
1902                                 cnt++;
1903                         this = (this+1) % disks;
1904                 }
1905                 if (cnt == 0)
1906                         goto out;
1907                 first = (first + ncopies) % disks;
1908         } while (first != 0);
1909         has_enough = 1;
1910 out:
1911         rcu_read_unlock();
1912         return has_enough;
1913 }
1914
1915 static int enough(struct r10conf *conf, int ignore)
1916 {
1917         /* when calling 'enough', both 'prev' and 'geo' must
1918          * be stable.
1919          * This is ensured if ->reconfig_mutex or ->device_lock
1920          * is held.
1921          */
1922         return _enough(conf, 0, ignore) &&
1923                 _enough(conf, 1, ignore);
1924 }
1925
1926 static void raid10_error(struct mddev *mddev, struct md_rdev *rdev)
1927 {
1928         char b[BDEVNAME_SIZE];
1929         struct r10conf *conf = mddev->private;
1930         unsigned long flags;
1931
1932         /*
1933          * If it is not operational, then we have already marked it as dead
1934          * else if it is the last working disks with "fail_last_dev == false",
1935          * ignore the error, let the next level up know.
1936          * else mark the drive as failed
1937          */
1938         spin_lock_irqsave(&conf->device_lock, flags);
1939         if (test_bit(In_sync, &rdev->flags) && !mddev->fail_last_dev
1940             && !enough(conf, rdev->raid_disk)) {
1941                 /*
1942                  * Don't fail the drive, just return an IO error.
1943                  */
1944                 spin_unlock_irqrestore(&conf->device_lock, flags);
1945                 return;
1946         }
1947         if (test_and_clear_bit(In_sync, &rdev->flags))
1948                 mddev->degraded++;
1949         /*
1950          * If recovery is running, make sure it aborts.
1951          */
1952         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1953         set_bit(Blocked, &rdev->flags);
1954         set_bit(Faulty, &rdev->flags);
1955         set_mask_bits(&mddev->sb_flags, 0,
1956                       BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
1957         spin_unlock_irqrestore(&conf->device_lock, flags);
1958         pr_crit("md/raid10:%s: Disk failure on %s, disabling device.\n"
1959                 "md/raid10:%s: Operation continuing on %d devices.\n",
1960                 mdname(mddev), bdevname(rdev->bdev, b),
1961                 mdname(mddev), conf->geo.raid_disks - mddev->degraded);
1962 }
1963
1964 static void print_conf(struct r10conf *conf)
1965 {
1966         int i;
1967         struct md_rdev *rdev;
1968
1969         pr_debug("RAID10 conf printout:\n");
1970         if (!conf) {
1971                 pr_debug("(!conf)\n");
1972                 return;
1973         }
1974         pr_debug(" --- wd:%d rd:%d\n", conf->geo.raid_disks - conf->mddev->degraded,
1975                  conf->geo.raid_disks);
1976
1977         /* This is only called with ->reconfix_mutex held, so
1978          * rcu protection of rdev is not needed */
1979         for (i = 0; i < conf->geo.raid_disks; i++) {
1980                 char b[BDEVNAME_SIZE];
1981                 rdev = conf->mirrors[i].rdev;
1982                 if (rdev)
1983                         pr_debug(" disk %d, wo:%d, o:%d, dev:%s\n",
1984                                  i, !test_bit(In_sync, &rdev->flags),
1985                                  !test_bit(Faulty, &rdev->flags),
1986                                  bdevname(rdev->bdev,b));
1987         }
1988 }
1989
1990 static void close_sync(struct r10conf *conf)
1991 {
1992         wait_barrier(conf);
1993         allow_barrier(conf);
1994
1995         mempool_exit(&conf->r10buf_pool);
1996 }
1997
1998 static int raid10_spare_active(struct mddev *mddev)
1999 {
2000         int i;
2001         struct r10conf *conf = mddev->private;
2002         struct raid10_info *tmp;
2003         int count = 0;
2004         unsigned long flags;
2005
2006         /*
2007          * Find all non-in_sync disks within the RAID10 configuration
2008          * and mark them in_sync
2009          */
2010         for (i = 0; i < conf->geo.raid_disks; i++) {
2011                 tmp = conf->mirrors + i;
2012                 if (tmp->replacement
2013                     && tmp->replacement->recovery_offset == MaxSector
2014                     && !test_bit(Faulty, &tmp->replacement->flags)
2015                     && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
2016                         /* Replacement has just become active */
2017                         if (!tmp->rdev
2018                             || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
2019                                 count++;
2020                         if (tmp->rdev) {
2021                                 /* Replaced device not technically faulty,
2022                                  * but we need to be sure it gets removed
2023                                  * and never re-added.
2024                                  */
2025                                 set_bit(Faulty, &tmp->rdev->flags);
2026                                 sysfs_notify_dirent_safe(
2027                                         tmp->rdev->sysfs_state);
2028                         }
2029                         sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
2030                 } else if (tmp->rdev
2031                            && tmp->rdev->recovery_offset == MaxSector
2032                            && !test_bit(Faulty, &tmp->rdev->flags)
2033                            && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
2034                         count++;
2035                         sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
2036                 }
2037         }
2038         spin_lock_irqsave(&conf->device_lock, flags);
2039         mddev->degraded -= count;
2040         spin_unlock_irqrestore(&conf->device_lock, flags);
2041
2042         print_conf(conf);
2043         return count;
2044 }
2045
2046 static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
2047 {
2048         struct r10conf *conf = mddev->private;
2049         int err = -EEXIST;
2050         int mirror;
2051         int first = 0;
2052         int last = conf->geo.raid_disks - 1;
2053
2054         if (mddev->recovery_cp < MaxSector)
2055                 /* only hot-add to in-sync arrays, as recovery is
2056                  * very different from resync
2057                  */
2058                 return -EBUSY;
2059         if (rdev->saved_raid_disk < 0 && !_enough(conf, 1, -1))
2060                 return -EINVAL;
2061
2062         if (md_integrity_add_rdev(rdev, mddev))
2063                 return -ENXIO;
2064
2065         if (rdev->raid_disk >= 0)
2066                 first = last = rdev->raid_disk;
2067
2068         if (rdev->saved_raid_disk >= first &&
2069             rdev->saved_raid_disk < conf->geo.raid_disks &&
2070             conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
2071                 mirror = rdev->saved_raid_disk;
2072         else
2073                 mirror = first;
2074         for ( ; mirror <= last ; mirror++) {
2075                 struct raid10_info *p = &conf->mirrors[mirror];
2076                 if (p->recovery_disabled == mddev->recovery_disabled)
2077                         continue;
2078                 if (p->rdev) {
2079                         if (!test_bit(WantReplacement, &p->rdev->flags) ||
2080                             p->replacement != NULL)
2081                                 continue;
2082                         clear_bit(In_sync, &rdev->flags);
2083                         set_bit(Replacement, &rdev->flags);
2084                         rdev->raid_disk = mirror;
2085                         err = 0;
2086                         if (mddev->gendisk)
2087                                 disk_stack_limits(mddev->gendisk, rdev->bdev,
2088                                                   rdev->data_offset << 9);
2089                         conf->fullsync = 1;
2090                         rcu_assign_pointer(p->replacement, rdev);
2091                         break;
2092                 }
2093
2094                 if (mddev->gendisk)
2095                         disk_stack_limits(mddev->gendisk, rdev->bdev,
2096                                           rdev->data_offset << 9);
2097
2098                 p->head_position = 0;
2099                 p->recovery_disabled = mddev->recovery_disabled - 1;
2100                 rdev->raid_disk = mirror;
2101                 err = 0;
2102                 if (rdev->saved_raid_disk != mirror)
2103                         conf->fullsync = 1;
2104                 rcu_assign_pointer(p->rdev, rdev);
2105                 break;
2106         }
2107         if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
2108                 blk_queue_flag_set(QUEUE_FLAG_DISCARD, mddev->queue);
2109
2110         print_conf(conf);
2111         return err;
2112 }
2113
2114 static int raid10_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
2115 {
2116         struct r10conf *conf = mddev->private;
2117         int err = 0;
2118         int number = rdev->raid_disk;
2119         struct md_rdev **rdevp;
2120         struct raid10_info *p = conf->mirrors + number;
2121
2122         print_conf(conf);
2123         if (rdev == p->rdev)
2124                 rdevp = &p->rdev;
2125         else if (rdev == p->replacement)
2126                 rdevp = &p->replacement;
2127         else
2128                 return 0;
2129
2130         if (test_bit(In_sync, &rdev->flags) ||
2131             atomic_read(&rdev->nr_pending)) {
2132                 err = -EBUSY;
2133                 goto abort;
2134         }
2135         /* Only remove non-faulty devices if recovery
2136          * is not possible.
2137          */
2138         if (!test_bit(Faulty, &rdev->flags) &&
2139             mddev->recovery_disabled != p->recovery_disabled &&
2140             (!p->replacement || p->replacement == rdev) &&
2141             number < conf->geo.raid_disks &&
2142             enough(conf, -1)) {
2143                 err = -EBUSY;
2144                 goto abort;
2145         }
2146         *rdevp = NULL;
2147         if (!test_bit(RemoveSynchronized, &rdev->flags)) {
2148                 synchronize_rcu();
2149                 if (atomic_read(&rdev->nr_pending)) {
2150                         /* lost the race, try later */
2151                         err = -EBUSY;
2152                         *rdevp = rdev;
2153                         goto abort;
2154                 }
2155         }
2156         if (p->replacement) {
2157                 /* We must have just cleared 'rdev' */
2158                 p->rdev = p->replacement;
2159                 clear_bit(Replacement, &p->replacement->flags);
2160                 smp_mb(); /* Make sure other CPUs may see both as identical
2161                            * but will never see neither -- if they are careful.
2162                            */
2163                 p->replacement = NULL;
2164         }
2165
2166         clear_bit(WantReplacement, &rdev->flags);
2167         err = md_integrity_register(mddev);
2168
2169 abort:
2170
2171         print_conf(conf);
2172         return err;
2173 }
2174
2175 static void __end_sync_read(struct r10bio *r10_bio, struct bio *bio, int d)
2176 {
2177         struct r10conf *conf = r10_bio->mddev->private;
2178
2179         if (!bio->bi_status)
2180                 set_bit(R10BIO_Uptodate, &r10_bio->state);
2181         else
2182                 /* The write handler will notice the lack of
2183                  * R10BIO_Uptodate and record any errors etc
2184                  */
2185                 atomic_add(r10_bio->sectors,
2186                            &conf->mirrors[d].rdev->corrected_errors);
2187
2188         /* for reconstruct, we always reschedule after a read.
2189          * for resync, only after all reads
2190          */
2191         rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev);
2192         if (test_bit(R10BIO_IsRecover, &r10_bio->state) ||
2193             atomic_dec_and_test(&r10_bio->remaining)) {
2194                 /* we have read all the blocks,
2195                  * do the comparison in process context in raid10d
2196                  */
2197                 reschedule_retry(r10_bio);
2198         }
2199 }
2200
2201 static void end_sync_read(struct bio *bio)
2202 {
2203         struct r10bio *r10_bio = get_resync_r10bio(bio);
2204         struct r10conf *conf = r10_bio->mddev->private;
2205         int d = find_bio_disk(conf, r10_bio, bio, NULL, NULL);
2206
2207         __end_sync_read(r10_bio, bio, d);
2208 }
2209
2210 static void end_reshape_read(struct bio *bio)
2211 {
2212         /* reshape read bio isn't allocated from r10buf_pool */
2213         struct r10bio *r10_bio = bio->bi_private;
2214
2215         __end_sync_read(r10_bio, bio, r10_bio->read_slot);
2216 }
2217
2218 static void end_sync_request(struct r10bio *r10_bio)
2219 {
2220         struct mddev *mddev = r10_bio->mddev;
2221
2222         while (atomic_dec_and_test(&r10_bio->remaining)) {
2223                 if (r10_bio->master_bio == NULL) {
2224                         /* the primary of several recovery bios */
2225                         sector_t s = r10_bio->sectors;
2226                         if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
2227                             test_bit(R10BIO_WriteError, &r10_bio->state))
2228                                 reschedule_retry(r10_bio);
2229                         else
2230                                 put_buf(r10_bio);
2231                         md_done_sync(mddev, s, 1);
2232                         break;
2233                 } else {
2234                         struct r10bio *r10_bio2 = (struct r10bio *)r10_bio->master_bio;
2235                         if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
2236                             test_bit(R10BIO_WriteError, &r10_bio->state))
2237                                 reschedule_retry(r10_bio);
2238                         else
2239                                 put_buf(r10_bio);
2240                         r10_bio = r10_bio2;
2241                 }
2242         }
2243 }
2244
2245 static void end_sync_write(struct bio *bio)
2246 {
2247         struct r10bio *r10_bio = get_resync_r10bio(bio);
2248         struct mddev *mddev = r10_bio->mddev;
2249         struct r10conf *conf = mddev->private;
2250         int d;
2251         sector_t first_bad;
2252         int bad_sectors;
2253         int slot;
2254         int repl;
2255         struct md_rdev *rdev = NULL;
2256
2257         d = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
2258         if (repl)
2259                 rdev = conf->mirrors[d].replacement;
2260         else
2261                 rdev = conf->mirrors[d].rdev;
2262
2263         if (bio->bi_status) {
2264                 if (repl)
2265                         md_error(mddev, rdev);
2266                 else {
2267                         set_bit(WriteErrorSeen, &rdev->flags);
2268                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
2269                                 set_bit(MD_RECOVERY_NEEDED,
2270                                         &rdev->mddev->recovery);
2271                         set_bit(R10BIO_WriteError, &r10_bio->state);
2272                 }
2273         } else if (is_badblock(rdev,
2274                              r10_bio->devs[slot].addr,
2275                              r10_bio->sectors,
2276                              &first_bad, &bad_sectors))
2277                 set_bit(R10BIO_MadeGood, &r10_bio->state);
2278
2279         rdev_dec_pending(rdev, mddev);
2280
2281         end_sync_request(r10_bio);
2282 }
2283
2284 /*
2285  * Note: sync and recover and handled very differently for raid10
2286  * This code is for resync.
2287  * For resync, we read through virtual addresses and read all blocks.
2288  * If there is any error, we schedule a write.  The lowest numbered
2289  * drive is authoritative.
2290  * However requests come for physical address, so we need to map.
2291  * For every physical address there are raid_disks/copies virtual addresses,
2292  * which is always are least one, but is not necessarly an integer.
2293  * This means that a physical address can span multiple chunks, so we may
2294  * have to submit multiple io requests for a single sync request.
2295  */
2296 /*
2297  * We check if all blocks are in-sync and only write to blocks that
2298  * aren't in sync
2299  */
2300 static void sync_request_write(struct mddev *mddev, struct r10bio *r10_bio)
2301 {
2302         struct r10conf *conf = mddev->private;
2303         int i, first;
2304         struct bio *tbio, *fbio;
2305         int vcnt;
2306         struct page **tpages, **fpages;
2307
2308         atomic_set(&r10_bio->remaining, 1);
2309
2310         /* find the first device with a block */
2311         for (i=0; i<conf->copies; i++)
2312                 if (!r10_bio->devs[i].bio->bi_status)
2313                         break;
2314
2315         if (i == conf->copies)
2316                 goto done;
2317
2318         first = i;
2319         fbio = r10_bio->devs[i].bio;
2320         fbio->bi_iter.bi_size = r10_bio->sectors << 9;
2321         fbio->bi_iter.bi_idx = 0;
2322         fpages = get_resync_pages(fbio)->pages;
2323
2324         vcnt = (r10_bio->sectors + (PAGE_SIZE >> 9) - 1) >> (PAGE_SHIFT - 9);
2325         /* now find blocks with errors */
2326         for (i=0 ; i < conf->copies ; i++) {
2327                 int  j, d;
2328                 struct md_rdev *rdev;
2329                 struct resync_pages *rp;
2330
2331                 tbio = r10_bio->devs[i].bio;
2332
2333                 if (tbio->bi_end_io != end_sync_read)
2334                         continue;
2335                 if (i == first)
2336                         continue;
2337
2338                 tpages = get_resync_pages(tbio)->pages;
2339                 d = r10_bio->devs[i].devnum;
2340                 rdev = conf->mirrors[d].rdev;
2341                 if (!r10_bio->devs[i].bio->bi_status) {
2342                         /* We know that the bi_io_vec layout is the same for
2343                          * both 'first' and 'i', so we just compare them.
2344                          * All vec entries are PAGE_SIZE;
2345                          */
2346                         int sectors = r10_bio->sectors;
2347                         for (j = 0; j < vcnt; j++) {
2348                                 int len = PAGE_SIZE;
2349                                 if (sectors < (len / 512))
2350                                         len = sectors * 512;
2351                                 if (memcmp(page_address(fpages[j]),
2352                                            page_address(tpages[j]),
2353                                            len))
2354                                         break;
2355                                 sectors -= len/512;
2356                         }
2357                         if (j == vcnt)
2358                                 continue;
2359                         atomic64_add(r10_bio->sectors, &mddev->resync_mismatches);
2360                         if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
2361                                 /* Don't fix anything. */
2362                                 continue;
2363                 } else if (test_bit(FailFast, &rdev->flags)) {
2364                         /* Just give up on this device */
2365                         md_error(rdev->mddev, rdev);
2366                         continue;
2367                 }
2368                 /* Ok, we need to write this bio, either to correct an
2369                  * inconsistency or to correct an unreadable block.
2370                  * First we need to fixup bv_offset, bv_len and
2371                  * bi_vecs, as the read request might have corrupted these
2372                  */
2373                 rp = get_resync_pages(tbio);
2374                 bio_reset(tbio);
2375
2376                 md_bio_reset_resync_pages(tbio, rp, fbio->bi_iter.bi_size);
2377
2378                 rp->raid_bio = r10_bio;
2379                 tbio->bi_private = rp;
2380                 tbio->bi_iter.bi_sector = r10_bio->devs[i].addr;
2381                 tbio->bi_end_io = end_sync_write;
2382                 bio_set_op_attrs(tbio, REQ_OP_WRITE, 0);
2383
2384                 bio_copy_data(tbio, fbio);
2385
2386                 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
2387                 atomic_inc(&r10_bio->remaining);
2388                 md_sync_acct(conf->mirrors[d].rdev->bdev, bio_sectors(tbio));
2389
2390                 if (test_bit(FailFast, &conf->mirrors[d].rdev->flags))
2391                         tbio->bi_opf |= MD_FAILFAST;
2392                 tbio->bi_iter.bi_sector += conf->mirrors[d].rdev->data_offset;
2393                 bio_set_dev(tbio, conf->mirrors[d].rdev->bdev);
2394                 submit_bio_noacct(tbio);
2395         }
2396
2397         /* Now write out to any replacement devices
2398          * that are active
2399          */
2400         for (i = 0; i < conf->copies; i++) {
2401                 int d;
2402
2403                 tbio = r10_bio->devs[i].repl_bio;
2404                 if (!tbio || !tbio->bi_end_io)
2405                         continue;
2406                 if (r10_bio->devs[i].bio->bi_end_io != end_sync_write
2407                     && r10_bio->devs[i].bio != fbio)
2408                         bio_copy_data(tbio, fbio);
2409                 d = r10_bio->devs[i].devnum;
2410                 atomic_inc(&r10_bio->remaining);
2411                 md_sync_acct(conf->mirrors[d].replacement->bdev,
2412                              bio_sectors(tbio));
2413                 submit_bio_noacct(tbio);
2414         }
2415
2416 done:
2417         if (atomic_dec_and_test(&r10_bio->remaining)) {
2418                 md_done_sync(mddev, r10_bio->sectors, 1);
2419                 put_buf(r10_bio);
2420         }
2421 }
2422
2423 /*
2424  * Now for the recovery code.
2425  * Recovery happens across physical sectors.
2426  * We recover all non-is_sync drives by finding the virtual address of
2427  * each, and then choose a working drive that also has that virt address.
2428  * There is a separate r10_bio for each non-in_sync drive.
2429  * Only the first two slots are in use. The first for reading,
2430  * The second for writing.
2431  *
2432  */
2433 static void fix_recovery_read_error(struct r10bio *r10_bio)
2434 {
2435         /* We got a read error during recovery.
2436          * We repeat the read in smaller page-sized sections.
2437          * If a read succeeds, write it to the new device or record
2438          * a bad block if we cannot.
2439          * If a read fails, record a bad block on both old and
2440          * new devices.
2441          */
2442         struct mddev *mddev = r10_bio->mddev;
2443         struct r10conf *conf = mddev->private;
2444         struct bio *bio = r10_bio->devs[0].bio;
2445         sector_t sect = 0;
2446         int sectors = r10_bio->sectors;
2447         int idx = 0;
2448         int dr = r10_bio->devs[0].devnum;
2449         int dw = r10_bio->devs[1].devnum;
2450         struct page **pages = get_resync_pages(bio)->pages;
2451
2452         while (sectors) {
2453                 int s = sectors;
2454                 struct md_rdev *rdev;
2455                 sector_t addr;
2456                 int ok;
2457
2458                 if (s > (PAGE_SIZE>>9))
2459                         s = PAGE_SIZE >> 9;
2460
2461                 rdev = conf->mirrors[dr].rdev;
2462                 addr = r10_bio->devs[0].addr + sect,
2463                 ok = sync_page_io(rdev,
2464                                   addr,
2465                                   s << 9,
2466                                   pages[idx],
2467                                   REQ_OP_READ, 0, false);
2468                 if (ok) {
2469                         rdev = conf->mirrors[dw].rdev;
2470                         addr = r10_bio->devs[1].addr + sect;
2471                         ok = sync_page_io(rdev,
2472                                           addr,
2473                                           s << 9,
2474                                           pages[idx],
2475                                           REQ_OP_WRITE, 0, false);
2476                         if (!ok) {
2477                                 set_bit(WriteErrorSeen, &rdev->flags);
2478                                 if (!test_and_set_bit(WantReplacement,
2479                                                       &rdev->flags))
2480                                         set_bit(MD_RECOVERY_NEEDED,
2481                                                 &rdev->mddev->recovery);
2482                         }
2483                 }
2484                 if (!ok) {
2485                         /* We don't worry if we cannot set a bad block -
2486                          * it really is bad so there is no loss in not
2487                          * recording it yet
2488                          */
2489                         rdev_set_badblocks(rdev, addr, s, 0);
2490
2491                         if (rdev != conf->mirrors[dw].rdev) {
2492                                 /* need bad block on destination too */
2493                                 struct md_rdev *rdev2 = conf->mirrors[dw].rdev;
2494                                 addr = r10_bio->devs[1].addr + sect;
2495                                 ok = rdev_set_badblocks(rdev2, addr, s, 0);
2496                                 if (!ok) {
2497                                         /* just abort the recovery */
2498                                         pr_notice("md/raid10:%s: recovery aborted due to read error\n",
2499                                                   mdname(mddev));
2500
2501                                         conf->mirrors[dw].recovery_disabled
2502                                                 = mddev->recovery_disabled;
2503                                         set_bit(MD_RECOVERY_INTR,
2504                                                 &mddev->recovery);
2505                                         break;
2506                                 }
2507                         }
2508                 }
2509
2510                 sectors -= s;
2511                 sect += s;
2512                 idx++;
2513         }
2514 }
2515
2516 static void recovery_request_write(struct mddev *mddev, struct r10bio *r10_bio)
2517 {
2518         struct r10conf *conf = mddev->private;
2519         int d;
2520         struct bio *wbio, *wbio2;
2521
2522         if (!test_bit(R10BIO_Uptodate, &r10_bio->state)) {
2523                 fix_recovery_read_error(r10_bio);
2524                 end_sync_request(r10_bio);
2525                 return;
2526         }
2527
2528         /*
2529          * share the pages with the first bio
2530          * and submit the write request
2531          */
2532         d = r10_bio->devs[1].devnum;
2533         wbio = r10_bio->devs[1].bio;
2534         wbio2 = r10_bio->devs[1].repl_bio;
2535         /* Need to test wbio2->bi_end_io before we call
2536          * submit_bio_noacct as if the former is NULL,
2537          * the latter is free to free wbio2.
2538          */
2539         if (wbio2 && !wbio2->bi_end_io)
2540                 wbio2 = NULL;
2541         if (wbio->bi_end_io) {
2542                 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
2543                 md_sync_acct(conf->mirrors[d].rdev->bdev, bio_sectors(wbio));
2544                 submit_bio_noacct(wbio);
2545         }
2546         if (wbio2) {
2547                 atomic_inc(&conf->mirrors[d].replacement->nr_pending);
2548                 md_sync_acct(conf->mirrors[d].replacement->bdev,
2549                              bio_sectors(wbio2));
2550                 submit_bio_noacct(wbio2);
2551         }
2552 }
2553
2554 /*
2555  * Used by fix_read_error() to decay the per rdev read_errors.
2556  * We halve the read error count for every hour that has elapsed
2557  * since the last recorded read error.
2558  *
2559  */
2560 static void check_decay_read_errors(struct mddev *mddev, struct md_rdev *rdev)
2561 {
2562         long cur_time_mon;
2563         unsigned long hours_since_last;
2564         unsigned int read_errors = atomic_read(&rdev->read_errors);
2565
2566         cur_time_mon = ktime_get_seconds();
2567
2568         if (rdev->last_read_error == 0) {
2569                 /* first time we've seen a read error */
2570                 rdev->last_read_error = cur_time_mon;
2571                 return;
2572         }
2573
2574         hours_since_last = (long)(cur_time_mon -
2575                             rdev->last_read_error) / 3600;
2576
2577         rdev->last_read_error = cur_time_mon;
2578
2579         /*
2580          * if hours_since_last is > the number of bits in read_errors
2581          * just set read errors to 0. We do this to avoid
2582          * overflowing the shift of read_errors by hours_since_last.
2583          */
2584         if (hours_since_last >= 8 * sizeof(read_errors))
2585                 atomic_set(&rdev->read_errors, 0);
2586         else
2587                 atomic_set(&rdev->read_errors, read_errors >> hours_since_last);
2588 }
2589
2590 static int r10_sync_page_io(struct md_rdev *rdev, sector_t sector,
2591                             int sectors, struct page *page, int rw)
2592 {
2593         sector_t first_bad;
2594         int bad_sectors;
2595
2596         if (is_badblock(rdev, sector, sectors, &first_bad, &bad_sectors)
2597             && (rw == READ || test_bit(WriteErrorSeen, &rdev->flags)))
2598                 return -1;
2599         if (sync_page_io(rdev, sector, sectors << 9, page, rw, 0, false))
2600                 /* success */
2601                 return 1;
2602         if (rw == WRITE) {
2603                 set_bit(WriteErrorSeen, &rdev->flags);
2604                 if (!test_and_set_bit(WantReplacement, &rdev->flags))
2605                         set_bit(MD_RECOVERY_NEEDED,
2606                                 &rdev->mddev->recovery);
2607         }
2608         /* need to record an error - either for the block or the device */
2609         if (!rdev_set_badblocks(rdev, sector, sectors, 0))
2610                 md_error(rdev->mddev, rdev);
2611         return 0;
2612 }
2613
2614 /*
2615  * This is a kernel thread which:
2616  *
2617  *      1.      Retries failed read operations on working mirrors.
2618  *      2.      Updates the raid superblock when problems encounter.
2619  *      3.      Performs writes following reads for array synchronising.
2620  */
2621
2622 static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10bio *r10_bio)
2623 {
2624         int sect = 0; /* Offset from r10_bio->sector */
2625         int sectors = r10_bio->sectors;
2626         struct md_rdev *rdev;
2627         int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
2628         int d = r10_bio->devs[r10_bio->read_slot].devnum;
2629
2630         /* still own a reference to this rdev, so it cannot
2631          * have been cleared recently.
2632          */
2633         rdev = conf->mirrors[d].rdev;
2634
2635         if (test_bit(Faulty, &rdev->flags))
2636                 /* drive has already been failed, just ignore any
2637                    more fix_read_error() attempts */
2638                 return;
2639
2640         check_decay_read_errors(mddev, rdev);
2641         atomic_inc(&rdev->read_errors);
2642         if (atomic_read(&rdev->read_errors) > max_read_errors) {
2643                 char b[BDEVNAME_SIZE];
2644                 bdevname(rdev->bdev, b);
2645
2646                 pr_notice("md/raid10:%s: %s: Raid device exceeded read_error threshold [cur %d:max %d]\n",
2647                           mdname(mddev), b,
2648                           atomic_read(&rdev->read_errors), max_read_errors);
2649                 pr_notice("md/raid10:%s: %s: Failing raid device\n",
2650                           mdname(mddev), b);
2651                 md_error(mddev, rdev);
2652                 r10_bio->devs[r10_bio->read_slot].bio = IO_BLOCKED;
2653                 return;
2654         }
2655
2656         while(sectors) {
2657                 int s = sectors;
2658                 int sl = r10_bio->read_slot;
2659                 int success = 0;
2660                 int start;
2661
2662                 if (s > (PAGE_SIZE>>9))
2663                         s = PAGE_SIZE >> 9;
2664
2665                 rcu_read_lock();
2666                 do {
2667                         sector_t first_bad;
2668                         int bad_sectors;
2669
2670                         d = r10_bio->devs[sl].devnum;
2671                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2672                         if (rdev &&
2673                             test_bit(In_sync, &rdev->flags) &&
2674                             !test_bit(Faulty, &rdev->flags) &&
2675                             is_badblock(rdev, r10_bio->devs[sl].addr + sect, s,
2676                                         &first_bad, &bad_sectors) == 0) {
2677                                 atomic_inc(&rdev->nr_pending);
2678                                 rcu_read_unlock();
2679                                 success = sync_page_io(rdev,
2680                                                        r10_bio->devs[sl].addr +
2681                                                        sect,
2682                                                        s<<9,
2683                                                        conf->tmppage,
2684                                                        REQ_OP_READ, 0, false);
2685                                 rdev_dec_pending(rdev, mddev);
2686                                 rcu_read_lock();
2687                                 if (success)
2688                                         break;
2689                         }
2690                         sl++;
2691                         if (sl == conf->copies)
2692                                 sl = 0;
2693                 } while (!success && sl != r10_bio->read_slot);
2694                 rcu_read_unlock();
2695
2696                 if (!success) {
2697                         /* Cannot read from anywhere, just mark the block
2698                          * as bad on the first device to discourage future
2699                          * reads.
2700                          */
2701                         int dn = r10_bio->devs[r10_bio->read_slot].devnum;
2702                         rdev = conf->mirrors[dn].rdev;
2703
2704                         if (!rdev_set_badblocks(
2705                                     rdev,
2706                                     r10_bio->devs[r10_bio->read_slot].addr
2707                                     + sect,
2708                                     s, 0)) {
2709                                 md_error(mddev, rdev);
2710                                 r10_bio->devs[r10_bio->read_slot].bio
2711                                         = IO_BLOCKED;
2712                         }
2713                         break;
2714                 }
2715
2716                 start = sl;
2717                 /* write it back and re-read */
2718                 rcu_read_lock();
2719                 while (sl != r10_bio->read_slot) {
2720                         char b[BDEVNAME_SIZE];
2721
2722                         if (sl==0)
2723                                 sl = conf->copies;
2724                         sl--;
2725                         d = r10_bio->devs[sl].devnum;
2726                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2727                         if (!rdev ||
2728                             test_bit(Faulty, &rdev->flags) ||
2729                             !test_bit(In_sync, &rdev->flags))
2730                                 continue;
2731
2732                         atomic_inc(&rdev->nr_pending);
2733                         rcu_read_unlock();
2734                         if (r10_sync_page_io(rdev,
2735                                              r10_bio->devs[sl].addr +
2736                                              sect,
2737                                              s, conf->tmppage, WRITE)
2738                             == 0) {
2739                                 /* Well, this device is dead */
2740                                 pr_notice("md/raid10:%s: read correction write failed (%d sectors at %llu on %s)\n",
2741                                           mdname(mddev), s,
2742                                           (unsigned long long)(
2743                                                   sect +
2744                                                   choose_data_offset(r10_bio,
2745                                                                      rdev)),
2746                                           bdevname(rdev->bdev, b));
2747                                 pr_notice("md/raid10:%s: %s: failing drive\n",
2748                                           mdname(mddev),
2749                                           bdevname(rdev->bdev, b));
2750                         }
2751                         rdev_dec_pending(rdev, mddev);
2752                         rcu_read_lock();
2753                 }
2754                 sl = start;
2755                 while (sl != r10_bio->read_slot) {
2756                         char b[BDEVNAME_SIZE];
2757
2758                         if (sl==0)
2759                                 sl = conf->copies;
2760                         sl--;
2761                         d = r10_bio->devs[sl].devnum;
2762                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2763                         if (!rdev ||
2764                             test_bit(Faulty, &rdev->flags) ||
2765                             !test_bit(In_sync, &rdev->flags))
2766                                 continue;
2767
2768                         atomic_inc(&rdev->nr_pending);
2769                         rcu_read_unlock();
2770                         switch (r10_sync_page_io(rdev,
2771                                              r10_bio->devs[sl].addr +
2772                                              sect,
2773                                              s, conf->tmppage,
2774                                                  READ)) {
2775                         case 0:
2776                                 /* Well, this device is dead */
2777                                 pr_notice("md/raid10:%s: unable to read back corrected sectors (%d sectors at %llu on %s)\n",
2778                                        mdname(mddev), s,
2779                                        (unsigned long long)(
2780                                                sect +
2781                                                choose_data_offset(r10_bio, rdev)),
2782                                        bdevname(rdev->bdev, b));
2783                                 pr_notice("md/raid10:%s: %s: failing drive\n",
2784                                        mdname(mddev),
2785                                        bdevname(rdev->bdev, b));
2786                                 break;
2787                         case 1:
2788                                 pr_info("md/raid10:%s: read error corrected (%d sectors at %llu on %s)\n",
2789                                        mdname(mddev), s,
2790                                        (unsigned long long)(
2791                                                sect +
2792                                                choose_data_offset(r10_bio, rdev)),
2793                                        bdevname(rdev->bdev, b));
2794                                 atomic_add(s, &rdev->corrected_errors);
2795                         }
2796
2797                         rdev_dec_pending(rdev, mddev);
2798                         rcu_read_lock();
2799                 }
2800                 rcu_read_unlock();
2801
2802                 sectors -= s;
2803                 sect += s;
2804         }
2805 }
2806
2807 static int narrow_write_error(struct r10bio *r10_bio, int i)
2808 {
2809         struct bio *bio = r10_bio->master_bio;
2810         struct mddev *mddev = r10_bio->mddev;
2811         struct r10conf *conf = mddev->private;
2812         struct md_rdev *rdev = conf->mirrors[r10_bio->devs[i].devnum].rdev;
2813         /* bio has the data to be written to slot 'i' where
2814          * we just recently had a write error.
2815          * We repeatedly clone the bio and trim down to one block,
2816          * then try the write.  Where the write fails we record
2817          * a bad block.
2818          * It is conceivable that the bio doesn't exactly align with
2819          * blocks.  We must handle this.
2820          *
2821          * We currently own a reference to the rdev.
2822          */
2823
2824         int block_sectors;
2825         sector_t sector;
2826         int sectors;
2827         int sect_to_write = r10_bio->sectors;
2828         int ok = 1;
2829
2830         if (rdev->badblocks.shift < 0)
2831                 return 0;
2832
2833         block_sectors = roundup(1 << rdev->badblocks.shift,
2834                                 bdev_logical_block_size(rdev->bdev) >> 9);
2835         sector = r10_bio->sector;
2836         sectors = ((r10_bio->sector + block_sectors)
2837                    & ~(sector_t)(block_sectors - 1))
2838                 - sector;
2839
2840         while (sect_to_write) {
2841                 struct bio *wbio;
2842                 sector_t wsector;
2843                 if (sectors > sect_to_write)
2844                         sectors = sect_to_write;
2845                 /* Write at 'sector' for 'sectors' */
2846                 wbio = bio_clone_fast(bio, GFP_NOIO, &mddev->bio_set);
2847                 bio_trim(wbio, sector - bio->bi_iter.bi_sector, sectors);
2848                 wsector = r10_bio->devs[i].addr + (sector - r10_bio->sector);
2849                 wbio->bi_iter.bi_sector = wsector +
2850                                    choose_data_offset(r10_bio, rdev);
2851                 bio_set_dev(wbio, rdev->bdev);
2852                 bio_set_op_attrs(wbio, REQ_OP_WRITE, 0);
2853
2854                 if (submit_bio_wait(wbio) < 0)
2855                         /* Failure! */
2856                         ok = rdev_set_badblocks(rdev, wsector,
2857                                                 sectors, 0)
2858                                 && ok;
2859
2860                 bio_put(wbio);
2861                 sect_to_write -= sectors;
2862                 sector += sectors;
2863                 sectors = block_sectors;
2864         }
2865         return ok;
2866 }
2867
2868 static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)
2869 {
2870         int slot = r10_bio->read_slot;
2871         struct bio *bio;
2872         struct r10conf *conf = mddev->private;
2873         struct md_rdev *rdev = r10_bio->devs[slot].rdev;
2874
2875         /* we got a read error. Maybe the drive is bad.  Maybe just
2876          * the block and we can fix it.
2877          * We freeze all other IO, and try reading the block from
2878          * other devices.  When we find one, we re-write
2879          * and check it that fixes the read error.
2880          * This is all done synchronously while the array is
2881          * frozen.
2882          */
2883         bio = r10_bio->devs[slot].bio;
2884         bio_put(bio);
2885         r10_bio->devs[slot].bio = NULL;
2886
2887         if (mddev->ro)
2888                 r10_bio->devs[slot].bio = IO_BLOCKED;
2889         else if (!test_bit(FailFast, &rdev->flags)) {
2890                 freeze_array(conf, 1);
2891                 fix_read_error(conf, mddev, r10_bio);
2892                 unfreeze_array(conf);
2893         } else
2894                 md_error(mddev, rdev);
2895
2896         rdev_dec_pending(rdev, mddev);
2897         allow_barrier(conf);
2898         r10_bio->state = 0;
2899         raid10_read_request(mddev, r10_bio->master_bio, r10_bio);
2900 }
2901
2902 static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)
2903 {
2904         /* Some sort of write request has finished and it
2905          * succeeded in writing where we thought there was a
2906          * bad block.  So forget the bad block.
2907          * Or possibly if failed and we need to record
2908          * a bad block.
2909          */
2910         int m;
2911         struct md_rdev *rdev;
2912
2913         if (test_bit(R10BIO_IsSync, &r10_bio->state) ||
2914             test_bit(R10BIO_IsRecover, &r10_bio->state)) {
2915                 for (m = 0; m < conf->copies; m++) {
2916                         int dev = r10_bio->devs[m].devnum;
2917                         rdev = conf->mirrors[dev].rdev;
2918                         if (r10_bio->devs[m].bio == NULL ||
2919                                 r10_bio->devs[m].bio->bi_end_io == NULL)
2920                                 continue;
2921                         if (!r10_bio->devs[m].bio->bi_status) {
2922                                 rdev_clear_badblocks(
2923                                         rdev,
2924                                         r10_bio->devs[m].addr,
2925                                         r10_bio->sectors, 0);
2926                         } else {
2927                                 if (!rdev_set_badblocks(
2928                                             rdev,
2929                                             r10_bio->devs[m].addr,
2930                                             r10_bio->sectors, 0))
2931                                         md_error(conf->mddev, rdev);
2932                         }
2933                         rdev = conf->mirrors[dev].replacement;
2934                         if (r10_bio->devs[m].repl_bio == NULL ||
2935                                 r10_bio->devs[m].repl_bio->bi_end_io == NULL)
2936                                 continue;
2937
2938                         if (!r10_bio->devs[m].repl_bio->bi_status) {
2939                                 rdev_clear_badblocks(
2940                                         rdev,
2941                                         r10_bio->devs[m].addr,
2942                                         r10_bio->sectors, 0);
2943                         } else {
2944                                 if (!rdev_set_badblocks(
2945                                             rdev,
2946                                             r10_bio->devs[m].addr,
2947                                             r10_bio->sectors, 0))
2948                                         md_error(conf->mddev, rdev);
2949                         }
2950                 }
2951                 put_buf(r10_bio);
2952         } else {
2953                 bool fail = false;
2954                 for (m = 0; m < conf->copies; m++) {
2955                         int dev = r10_bio->devs[m].devnum;
2956                         struct bio *bio = r10_bio->devs[m].bio;
2957                         rdev = conf->mirrors[dev].rdev;
2958                         if (bio == IO_MADE_GOOD) {
2959                                 rdev_clear_badblocks(
2960                                         rdev,
2961                                         r10_bio->devs[m].addr,
2962                                         r10_bio->sectors, 0);
2963                                 rdev_dec_pending(rdev, conf->mddev);
2964                         } else if (bio != NULL && bio->bi_status) {
2965                                 fail = true;
2966                                 if (!narrow_write_error(r10_bio, m)) {
2967                                         md_error(conf->mddev, rdev);
2968                                         set_bit(R10BIO_Degraded,
2969                                                 &r10_bio->state);
2970                                 }
2971                                 rdev_dec_pending(rdev, conf->mddev);
2972                         }
2973                         bio = r10_bio->devs[m].repl_bio;
2974                         rdev = conf->mirrors[dev].replacement;
2975                         if (rdev && bio == IO_MADE_GOOD) {
2976                                 rdev_clear_badblocks(
2977                                         rdev,
2978                                         r10_bio->devs[m].addr,
2979                                         r10_bio->sectors, 0);
2980                                 rdev_dec_pending(rdev, conf->mddev);
2981                         }
2982                 }
2983                 if (fail) {
2984                         spin_lock_irq(&conf->device_lock);
2985                         list_add(&r10_bio->retry_list, &conf->bio_end_io_list);
2986                         conf->nr_queued++;
2987                         spin_unlock_irq(&conf->device_lock);
2988                         /*
2989                          * In case freeze_array() is waiting for condition
2990                          * nr_pending == nr_queued + extra to be true.
2991                          */
2992                         wake_up(&conf->wait_barrier);
2993                         md_wakeup_thread(conf->mddev->thread);
2994                 } else {
2995                         if (test_bit(R10BIO_WriteError,
2996                                      &r10_bio->state))
2997                                 close_write(r10_bio);
2998                         raid_end_bio_io(r10_bio);
2999                 }
3000         }
3001 }
3002
3003 static void raid10d(struct md_thread *thread)
3004 {
3005         struct mddev *mddev = thread->mddev;
3006         struct r10bio *r10_bio;
3007         unsigned long flags;
3008         struct r10conf *conf = mddev->private;
3009         struct list_head *head = &conf->retry_list;
3010         struct blk_plug plug;
3011
3012         md_check_recovery(mddev);
3013
3014         if (!list_empty_careful(&conf->bio_end_io_list) &&
3015             !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
3016                 LIST_HEAD(tmp);
3017                 spin_lock_irqsave(&conf->device_lock, flags);
3018                 if (!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
3019                         while (!list_empty(&conf->bio_end_io_list)) {
3020                                 list_move(conf->bio_end_io_list.prev, &tmp);
3021                                 conf->nr_queued--;
3022                         }
3023                 }
3024                 spin_unlock_irqrestore(&conf->device_lock, flags);
3025                 while (!list_empty(&tmp)) {
3026                         r10_bio = list_first_entry(&tmp, struct r10bio,
3027                                                    retry_list);
3028                         list_del(&r10_bio->retry_list);
3029                         if (mddev->degraded)
3030                                 set_bit(R10BIO_Degraded, &r10_bio->state);
3031
3032                         if (test_bit(R10BIO_WriteError,
3033                                      &r10_bio->state))
3034                                 close_write(r10_bio);
3035                         raid_end_bio_io(r10_bio);
3036                 }
3037         }
3038
3039         blk_start_plug(&plug);
3040         for (;;) {
3041
3042                 flush_pending_writes(conf);
3043
3044                 spin_lock_irqsave(&conf->device_lock, flags);
3045                 if (list_empty(head)) {
3046                         spin_unlock_irqrestore(&conf->device_lock, flags);
3047                         break;
3048                 }
3049                 r10_bio = list_entry(head->prev, struct r10bio, retry_list);
3050                 list_del(head->prev);
3051                 conf->nr_queued--;
3052                 spin_unlock_irqrestore(&conf->device_lock, flags);
3053
3054                 mddev = r10_bio->mddev;
3055                 conf = mddev->private;
3056                 if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
3057                     test_bit(R10BIO_WriteError, &r10_bio->state))
3058                         handle_write_completed(conf, r10_bio);
3059                 else if (test_bit(R10BIO_IsReshape, &r10_bio->state))
3060                         reshape_request_write(mddev, r10_bio);
3061                 else if (test_bit(R10BIO_IsSync, &r10_bio->state))
3062                         sync_request_write(mddev, r10_bio);
3063                 else if (test_bit(R10BIO_IsRecover, &r10_bio->state))
3064                         recovery_request_write(mddev, r10_bio);
3065                 else if (test_bit(R10BIO_ReadError, &r10_bio->state))
3066                         handle_read_error(mddev, r10_bio);
3067                 else
3068                         WARN_ON_ONCE(1);
3069
3070                 cond_resched();
3071                 if (mddev->sb_flags & ~(1<<MD_SB_CHANGE_PENDING))
3072                         md_check_recovery(mddev);
3073         }
3074         blk_finish_plug(&plug);
3075 }
3076
3077 static int init_resync(struct r10conf *conf)
3078 {
3079         int ret, buffs, i;
3080
3081         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
3082         BUG_ON(mempool_initialized(&conf->r10buf_pool));
3083         conf->have_replacement = 0;
3084         for (i = 0; i < conf->geo.raid_disks; i++)
3085                 if (conf->mirrors[i].replacement)
3086                         conf->have_replacement = 1;
3087         ret = mempool_init(&conf->r10buf_pool, buffs,
3088                            r10buf_pool_alloc, r10buf_pool_free, conf);
3089         if (ret)
3090                 return ret;
3091         conf->next_resync = 0;
3092         return 0;
3093 }
3094
3095 static struct r10bio *raid10_alloc_init_r10buf(struct r10conf *conf)
3096 {
3097         struct r10bio *r10bio = mempool_alloc(&conf->r10buf_pool, GFP_NOIO);
3098         struct rsync_pages *rp;
3099         struct bio *bio;
3100         int nalloc;
3101         int i;
3102
3103         if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery) ||
3104             test_bit(MD_RECOVERY_RESHAPE, &conf->mddev->recovery))
3105                 nalloc = conf->copies; /* resync */
3106         else
3107                 nalloc = 2; /* recovery */
3108
3109         for (i = 0; i < nalloc; i++) {
3110                 bio = r10bio->devs[i].bio;
3111                 rp = bio->bi_private;
3112                 bio_reset(bio);
3113                 bio->bi_private = rp;
3114                 bio = r10bio->devs[i].repl_bio;
3115                 if (bio) {
3116                         rp = bio->bi_private;
3117                         bio_reset(bio);
3118                         bio->bi_private = rp;
3119                 }
3120         }
3121         return r10bio;
3122 }
3123
3124 /*
3125  * Set cluster_sync_high since we need other nodes to add the
3126  * range [cluster_sync_low, cluster_sync_high] to suspend list.
3127  */
3128 static void raid10_set_cluster_sync_high(struct r10conf *conf)
3129 {
3130         sector_t window_size;
3131         int extra_chunk, chunks;
3132
3133         /*
3134          * First, here we define "stripe" as a unit which across
3135          * all member devices one time, so we get chunks by use
3136          * raid_disks / near_copies. Otherwise, if near_copies is
3137          * close to raid_disks, then resync window could increases
3138          * linearly with the increase of raid_disks, which means
3139          * we will suspend a really large IO window while it is not
3140          * necessary. If raid_disks is not divisible by near_copies,
3141          * an extra chunk is needed to ensure the whole "stripe" is
3142          * covered.
3143          */
3144
3145         chunks = conf->geo.raid_disks / conf->geo.near_copies;
3146         if (conf->geo.raid_disks % conf->geo.near_copies == 0)
3147                 extra_chunk = 0;
3148         else
3149                 extra_chunk = 1;
3150         window_size = (chunks + extra_chunk) * conf->mddev->chunk_sectors;
3151
3152         /*
3153          * At least use a 32M window to align with raid1's resync window
3154          */
3155         window_size = (CLUSTER_RESYNC_WINDOW_SECTORS > window_size) ?
3156                         CLUSTER_RESYNC_WINDOW_SECTORS : window_size;
3157
3158         conf->cluster_sync_high = conf->cluster_sync_low + window_size;
3159 }
3160
3161 /*
3162  * perform a "sync" on one "block"
3163  *
3164  * We need to make sure that no normal I/O request - particularly write
3165  * requests - conflict with active sync requests.
3166  *
3167  * This is achieved by tracking pending requests and a 'barrier' concept
3168  * that can be installed to exclude normal IO requests.
3169  *
3170  * Resync and recovery are handled very differently.
3171  * We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery.
3172  *
3173  * For resync, we iterate over virtual addresses, read all copies,
3174  * and update if there are differences.  If only one copy is live,
3175  * skip it.
3176  * For recovery, we iterate over physical addresses, read a good
3177  * value for each non-in_sync drive, and over-write.
3178  *
3179  * So, for recovery we may have several outstanding complex requests for a
3180  * given address, one for each out-of-sync device.  We model this by allocating
3181  * a number of r10_bio structures, one for each out-of-sync device.
3182  * As we setup these structures, we collect all bio's together into a list
3183  * which we then process collectively to add pages, and then process again
3184  * to pass to submit_bio_noacct.
3185  *
3186  * The r10_bio structures are linked using a borrowed master_bio pointer.
3187  * This link is counted in ->remaining.  When the r10_bio that points to NULL
3188  * has its remaining count decremented to 0, the whole complex operation
3189  * is complete.
3190  *
3191  */
3192
3193 static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
3194                              int *skipped)
3195 {
3196         struct r10conf *conf = mddev->private;
3197         struct r10bio *r10_bio;
3198         struct bio *biolist = NULL, *bio;
3199         sector_t max_sector, nr_sectors;
3200         int i;
3201         int max_sync;
3202         sector_t sync_blocks;
3203         sector_t sectors_skipped = 0;
3204         int chunks_skipped = 0;
3205         sector_t chunk_mask = conf->geo.chunk_mask;
3206         int page_idx = 0;
3207
3208         if (!mempool_initialized(&conf->r10buf_pool))
3209                 if (init_resync(conf))
3210                         return 0;
3211
3212         /*
3213          * Allow skipping a full rebuild for incremental assembly
3214          * of a clean array, like RAID1 does.
3215          */
3216         if (mddev->bitmap == NULL &&
3217             mddev->recovery_cp == MaxSector &&
3218             mddev->reshape_position == MaxSector &&
3219             !test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
3220             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
3221             !test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
3222             conf->fullsync == 0) {
3223                 *skipped = 1;
3224                 return mddev->dev_sectors - sector_nr;
3225         }
3226
3227  skipped:
3228         max_sector = mddev->dev_sectors;
3229         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ||
3230             test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
3231                 max_sector = mddev->resync_max_sectors;
3232         if (sector_nr >= max_sector) {
3233                 conf->cluster_sync_low = 0;
3234                 conf->cluster_sync_high = 0;
3235
3236                 /* If we aborted, we need to abort the
3237                  * sync on the 'current' bitmap chucks (there can
3238                  * be several when recovering multiple devices).
3239                  * as we may have started syncing it but not finished.
3240                  * We can find the current address in
3241                  * mddev->curr_resync, but for recovery,
3242                  * we need to convert that to several
3243                  * virtual addresses.
3244                  */
3245                 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
3246                         end_reshape(conf);
3247                         close_sync(conf);
3248                         return 0;
3249                 }
3250
3251                 if (mddev->curr_resync < max_sector) { /* aborted */
3252                         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
3253                                 md_bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
3254                                                    &sync_blocks, 1);
3255                         else for (i = 0; i < conf->geo.raid_disks; i++) {
3256                                 sector_t sect =
3257                                         raid10_find_virt(conf, mddev->curr_resync, i);
3258                                 md_bitmap_end_sync(mddev->bitmap, sect,
3259                                                    &sync_blocks, 1);
3260                         }
3261                 } else {
3262                         /* completed sync */
3263                         if ((!mddev->bitmap || conf->fullsync)
3264                             && conf->have_replacement
3265                             && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
3266                                 /* Completed a full sync so the replacements
3267                                  * are now fully recovered.
3268                                  */
3269                                 rcu_read_lock();
3270                                 for (i = 0; i < conf->geo.raid_disks; i++) {
3271                                         struct md_rdev *rdev =
3272                                                 rcu_dereference(conf->mirrors[i].replacement);
3273                                         if (rdev)
3274                                                 rdev->recovery_offset = MaxSector;
3275                                 }
3276                                 rcu_read_unlock();
3277                         }
3278                         conf->fullsync = 0;
3279                 }
3280                 md_bitmap_close_sync(mddev->bitmap);
3281                 close_sync(conf);
3282                 *skipped = 1;
3283                 return sectors_skipped;
3284         }
3285
3286         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
3287                 return reshape_request(mddev, sector_nr, skipped);
3288
3289         if (chunks_skipped >= conf->geo.raid_disks) {
3290                 /* if there has been nothing to do on any drive,
3291                  * then there is nothing to do at all..
3292                  */
3293                 *skipped = 1;
3294                 return (max_sector - sector_nr) + sectors_skipped;
3295         }
3296
3297         if (max_sector > mddev->resync_max)
3298                 max_sector = mddev->resync_max; /* Don't do IO beyond here */
3299
3300         /* make sure whole request will fit in a chunk - if chunks
3301          * are meaningful
3302          */
3303         if (conf->geo.near_copies < conf->geo.raid_disks &&
3304             max_sector > (sector_nr | chunk_mask))
3305                 max_sector = (sector_nr | chunk_mask) + 1;
3306
3307         /*
3308          * If there is non-resync activity waiting for a turn, then let it
3309          * though before starting on this new sync request.
3310          */
3311         if (conf->nr_waiting)
3312                 schedule_timeout_uninterruptible(1);
3313
3314         /* Again, very different code for resync and recovery.
3315          * Both must result in an r10bio with a list of bios that
3316          * have bi_end_io, bi_sector, bi_disk set,
3317          * and bi_private set to the r10bio.
3318          * For recovery, we may actually create several r10bios
3319          * with 2 bios in each, that correspond to the bios in the main one.
3320          * In this case, the subordinate r10bios link back through a
3321          * borrowed master_bio pointer, and the counter in the master
3322          * includes a ref from each subordinate.
3323          */
3324         /* First, we decide what to do and set ->bi_end_io
3325          * To end_sync_read if we want to read, and
3326          * end_sync_write if we will want to write.
3327          */
3328
3329         max_sync = RESYNC_PAGES << (PAGE_SHIFT-9);
3330         if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
3331                 /* recovery... the complicated one */
3332                 int j;
3333                 r10_bio = NULL;
3334
3335                 for (i = 0 ; i < conf->geo.raid_disks; i++) {
3336                         int still_degraded;
3337                         struct r10bio *rb2;
3338                         sector_t sect;
3339                         int must_sync;
3340                         int any_working;
3341                         int need_recover = 0;
3342                         int need_replace = 0;
3343                         struct raid10_info *mirror = &conf->mirrors[i];
3344                         struct md_rdev *mrdev, *mreplace;
3345
3346                         rcu_read_lock();
3347                         mrdev = rcu_dereference(mirror->rdev);
3348                         mreplace = rcu_dereference(mirror->replacement);
3349
3350                         if (mrdev != NULL &&
3351                             !test_bit(Faulty, &mrdev->flags) &&
3352                             !test_bit(In_sync, &mrdev->flags))
3353                                 need_recover = 1;
3354                         if (mreplace != NULL &&
3355                             !test_bit(Faulty, &mreplace->flags))
3356                                 need_replace = 1;
3357
3358                         if (!need_recover && !need_replace) {
3359                                 rcu_read_unlock();
3360                                 continue;
3361                         }
3362
3363                         still_degraded = 0;
3364                         /* want to reconstruct this device */
3365                         rb2 = r10_bio;
3366                         sect = raid10_find_virt(conf, sector_nr, i);
3367                         if (sect >= mddev->resync_max_sectors) {
3368                                 /* last stripe is not complete - don't
3369                                  * try to recover this sector.
3370                                  */
3371                                 rcu_read_unlock();
3372                                 continue;
3373                         }
3374                         if (mreplace && test_bit(Faulty, &mreplace->flags))
3375                                 mreplace = NULL;
3376                         /* Unless we are doing a full sync, or a replacement
3377                          * we only need to recover the block if it is set in
3378                          * the bitmap
3379                          */
3380                         must_sync = md_bitmap_start_sync(mddev->bitmap, sect,
3381                                                          &sync_blocks, 1);
3382                         if (sync_blocks < max_sync)
3383                                 max_sync = sync_blocks;
3384                         if (!must_sync &&
3385                             mreplace == NULL &&
3386                             !conf->fullsync) {
3387                                 /* yep, skip the sync_blocks here, but don't assume
3388                                  * that there will never be anything to do here
3389                                  */
3390                                 chunks_skipped = -1;
3391                                 rcu_read_unlock();
3392                                 continue;
3393                         }
3394                         atomic_inc(&mrdev->nr_pending);
3395                         if (mreplace)
3396                                 atomic_inc(&mreplace->nr_pending);
3397                         rcu_read_unlock();
3398
3399                         r10_bio = raid10_alloc_init_r10buf(conf);
3400                         r10_bio->state = 0;
3401                         raise_barrier(conf, rb2 != NULL);
3402                         atomic_set(&r10_bio->remaining, 0);
3403
3404                         r10_bio->master_bio = (struct bio*)rb2;
3405                         if (rb2)
3406                                 atomic_inc(&rb2->remaining);
3407                         r10_bio->mddev = mddev;
3408                         set_bit(R10BIO_IsRecover, &r10_bio->state);
3409                         r10_bio->sector = sect;
3410
3411                         raid10_find_phys(conf, r10_bio);
3412
3413                         /* Need to check if the array will still be
3414                          * degraded
3415                          */
3416                         rcu_read_lock();
3417                         for (j = 0; j < conf->geo.raid_disks; j++) {
3418                                 struct md_rdev *rdev = rcu_dereference(
3419                                         conf->mirrors[j].rdev);
3420                                 if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
3421                                         still_degraded = 1;
3422                                         break;
3423                                 }
3424                         }
3425
3426                         must_sync = md_bitmap_start_sync(mddev->bitmap, sect,
3427                                                          &sync_blocks, still_degraded);
3428
3429                         any_working = 0;
3430                         for (j=0; j<conf->copies;j++) {
3431                                 int k;
3432                                 int d = r10_bio->devs[j].devnum;
3433                                 sector_t from_addr, to_addr;
3434                                 struct md_rdev *rdev =
3435                                         rcu_dereference(conf->mirrors[d].rdev);
3436                                 sector_t sector, first_bad;
3437                                 int bad_sectors;
3438                                 if (!rdev ||
3439                                     !test_bit(In_sync, &rdev->flags))
3440                                         continue;
3441                                 /* This is where we read from */
3442                                 any_working = 1;
3443                                 sector = r10_bio->devs[j].addr;
3444
3445                                 if (is_badblock(rdev, sector, max_sync,
3446                                                 &first_bad, &bad_sectors)) {
3447                                         if (first_bad > sector)
3448                                                 max_sync = first_bad - sector;
3449                                         else {
3450                                                 bad_sectors -= (sector
3451                                                                 - first_bad);
3452                                                 if (max_sync > bad_sectors)
3453                                                         max_sync = bad_sectors;
3454                                                 continue;
3455                                         }
3456                                 }
3457                                 bio = r10_bio->devs[0].bio;
3458                                 bio->bi_next = biolist;
3459                                 biolist = bio;
3460                                 bio->bi_end_io = end_sync_read;
3461                                 bio_set_op_attrs(bio, REQ_OP_READ, 0);
3462                                 if (test_bit(FailFast, &rdev->flags))
3463                                         bio->bi_opf |= MD_FAILFAST;
3464                                 from_addr = r10_bio->devs[j].addr;
3465                                 bio->bi_iter.bi_sector = from_addr +
3466                                         rdev->data_offset;
3467                                 bio_set_dev(bio, rdev->bdev);
3468                                 atomic_inc(&rdev->nr_pending);
3469                                 /* and we write to 'i' (if not in_sync) */
3470
3471                                 for (k=0; k<conf->copies; k++)
3472                                         if (r10_bio->devs[k].devnum == i)
3473                                                 break;
3474                                 BUG_ON(k == conf->copies);
3475                                 to_addr = r10_bio->devs[k].addr;
3476                                 r10_bio->devs[0].devnum = d;
3477                                 r10_bio->devs[0].addr = from_addr;
3478                                 r10_bio->devs[1].devnum = i;
3479                                 r10_bio->devs[1].addr = to_addr;
3480
3481                                 if (need_recover) {
3482                                         bio = r10_bio->devs[1].bio;
3483                                         bio->bi_next = biolist;
3484                                         biolist = bio;
3485                                         bio->bi_end_io = end_sync_write;
3486                                         bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
3487                                         bio->bi_iter.bi_sector = to_addr
3488                                                 + mrdev->data_offset;
3489                                         bio_set_dev(bio, mrdev->bdev);
3490                                         atomic_inc(&r10_bio->remaining);
3491                                 } else
3492                                         r10_bio->devs[1].bio->bi_end_io = NULL;
3493
3494                                 /* and maybe write to replacement */
3495                                 bio = r10_bio->devs[1].repl_bio;
3496                                 if (bio)
3497                                         bio->bi_end_io = NULL;
3498                                 /* Note: if need_replace, then bio
3499                                  * cannot be NULL as r10buf_pool_alloc will
3500                                  * have allocated it.
3501                                  */
3502                                 if (!need_replace)
3503                                         break;
3504                                 bio->bi_next = biolist;
3505                                 biolist = bio;
3506                                 bio->bi_end_io = end_sync_write;
3507                                 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
3508                                 bio->bi_iter.bi_sector = to_addr +
3509                                         mreplace->data_offset;
3510                                 bio_set_dev(bio, mreplace->bdev);
3511                                 atomic_inc(&r10_bio->remaining);
3512                                 break;
3513                         }
3514                         rcu_read_unlock();
3515                         if (j == conf->copies) {
3516                                 /* Cannot recover, so abort the recovery or
3517                                  * record a bad block */
3518                                 if (any_working) {
3519                                         /* problem is that there are bad blocks
3520                                          * on other device(s)
3521                                          */
3522                                         int k;
3523                                         for (k = 0; k < conf->copies; k++)
3524                                                 if (r10_bio->devs[k].devnum == i)
3525                                                         break;
3526                                         if (!test_bit(In_sync,
3527                                                       &mrdev->flags)
3528                                             && !rdev_set_badblocks(
3529                                                     mrdev,
3530                                                     r10_bio->devs[k].addr,
3531                                                     max_sync, 0))
3532                                                 any_working = 0;
3533                                         if (mreplace &&
3534                                             !rdev_set_badblocks(
3535                                                     mreplace,
3536                                                     r10_bio->devs[k].addr,
3537                                                     max_sync, 0))
3538                                                 any_working = 0;
3539                                 }
3540                                 if (!any_working)  {
3541                                         if (!test_and_set_bit(MD_RECOVERY_INTR,
3542                                                               &mddev->recovery))
3543                                                 pr_warn("md/raid10:%s: insufficient working devices for recovery.\n",
3544                                                        mdname(mddev));
3545                                         mirror->recovery_disabled
3546                                                 = mddev->recovery_disabled;
3547                                 }
3548                                 put_buf(r10_bio);
3549                                 if (rb2)
3550                                         atomic_dec(&rb2->remaining);
3551                                 r10_bio = rb2;
3552                                 rdev_dec_pending(mrdev, mddev);
3553                                 if (mreplace)
3554                                         rdev_dec_pending(mreplace, mddev);
3555                                 break;
3556                         }
3557                         rdev_dec_pending(mrdev, mddev);
3558                         if (mreplace)
3559                                 rdev_dec_pending(mreplace, mddev);
3560                         if (r10_bio->devs[0].bio->bi_opf & MD_FAILFAST) {
3561                                 /* Only want this if there is elsewhere to
3562                                  * read from. 'j' is currently the first
3563                                  * readable copy.
3564                                  */
3565                                 int targets = 1;
3566                                 for (; j < conf->copies; j++) {
3567                                         int d = r10_bio->devs[j].devnum;
3568                                         if (conf->mirrors[d].rdev &&
3569                                             test_bit(In_sync,
3570                                                       &conf->mirrors[d].rdev->flags))
3571                                                 targets++;
3572                                 }
3573                                 if (targets == 1)
3574                                         r10_bio->devs[0].bio->bi_opf
3575                                                 &= ~MD_FAILFAST;
3576                         }
3577                 }
3578                 if (biolist == NULL) {
3579                         while (r10_bio) {
3580                                 struct r10bio *rb2 = r10_bio;
3581                                 r10_bio = (struct r10bio*) rb2->master_bio;
3582                                 rb2->master_bio = NULL;
3583                                 put_buf(rb2);
3584                         }
3585                         goto giveup;
3586                 }
3587         } else {
3588                 /* resync. Schedule a read for every block at this virt offset */
3589                 int count = 0;
3590
3591                 /*
3592                  * Since curr_resync_completed could probably not update in
3593                  * time, and we will set cluster_sync_low based on it.
3594                  * Let's check against "sector_nr + 2 * RESYNC_SECTORS" for
3595                  * safety reason, which ensures curr_resync_completed is
3596                  * updated in bitmap_cond_end_sync.
3597                  */
3598                 md_bitmap_cond_end_sync(mddev->bitmap, sector_nr,
3599                                         mddev_is_clustered(mddev) &&
3600                                         (sector_nr + 2 * RESYNC_SECTORS > conf->cluster_sync_high));
3601
3602                 if (!md_bitmap_start_sync(mddev->bitmap, sector_nr,
3603                                           &sync_blocks, mddev->degraded) &&
3604                     !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED,
3605                                                  &mddev->recovery)) {
3606                         /* We can skip this block */
3607                         *skipped = 1;
3608                         return sync_blocks + sectors_skipped;
3609                 }
3610                 if (sync_blocks < max_sync)
3611                         max_sync = sync_blocks;
3612                 r10_bio = raid10_alloc_init_r10buf(conf);
3613                 r10_bio->state = 0;
3614
3615                 r10_bio->mddev = mddev;
3616                 atomic_set(&r10_bio->remaining, 0);
3617                 raise_barrier(conf, 0);
3618                 conf->next_resync = sector_nr;
3619
3620                 r10_bio->master_bio = NULL;
3621                 r10_bio->sector = sector_nr;
3622                 set_bit(R10BIO_IsSync, &r10_bio->state);
3623                 raid10_find_phys(conf, r10_bio);
3624                 r10_bio->sectors = (sector_nr | chunk_mask) - sector_nr + 1;
3625
3626                 for (i = 0; i < conf->copies; i++) {
3627                         int d = r10_bio->devs[i].devnum;
3628                         sector_t first_bad, sector;
3629                         int bad_sectors;
3630                         struct md_rdev *rdev;
3631
3632                         if (r10_bio->devs[i].repl_bio)
3633                                 r10_bio->devs[i].repl_bio->bi_end_io = NULL;
3634
3635                         bio = r10_bio->devs[i].bio;
3636                         bio->bi_status = BLK_STS_IOERR;
3637                         rcu_read_lock();
3638                         rdev = rcu_dereference(conf->mirrors[d].rdev);
3639                         if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
3640                                 rcu_read_unlock();
3641                                 continue;
3642                         }
3643                         sector = r10_bio->devs[i].addr;
3644                         if (is_badblock(rdev, sector, max_sync,
3645                                         &first_bad, &bad_sectors)) {
3646                                 if (first_bad > sector)
3647                                         max_sync = first_bad - sector;
3648                                 else {
3649                                         bad_sectors -= (sector - first_bad);
3650                                         if (max_sync > bad_sectors)
3651                                                 max_sync = bad_sectors;
3652                                         rcu_read_unlock();
3653                                         continue;
3654                                 }
3655                         }
3656                         atomic_inc(&rdev->nr_pending);
3657                         atomic_inc(&r10_bio->remaining);
3658                         bio->bi_next = biolist;
3659                         biolist = bio;
3660                         bio->bi_end_io = end_sync_read;
3661                         bio_set_op_attrs(bio, REQ_OP_READ, 0);
3662                         if (test_bit(FailFast, &rdev->flags))
3663                                 bio->bi_opf |= MD_FAILFAST;
3664                         bio->bi_iter.bi_sector = sector + rdev->data_offset;
3665                         bio_set_dev(bio, rdev->bdev);
3666                         count++;
3667
3668                         rdev = rcu_dereference(conf->mirrors[d].replacement);
3669                         if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
3670                                 rcu_read_unlock();
3671                                 continue;
3672                         }
3673                         atomic_inc(&rdev->nr_pending);
3674
3675                         /* Need to set up for writing to the replacement */
3676                         bio = r10_bio->devs[i].repl_bio;
3677                         bio->bi_status = BLK_STS_IOERR;
3678
3679                         sector = r10_bio->devs[i].addr;
3680                         bio->bi_next = biolist;
3681                         biolist = bio;
3682                         bio->bi_end_io = end_sync_write;
3683                         bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
3684                         if (test_bit(FailFast, &rdev->flags))
3685                                 bio->bi_opf |= MD_FAILFAST;
3686                         bio->bi_iter.bi_sector = sector + rdev->data_offset;
3687                         bio_set_dev(bio, rdev->bdev);
3688                         count++;
3689                         rcu_read_unlock();
3690                 }
3691
3692                 if (count < 2) {
3693                         for (i=0; i<conf->copies; i++) {
3694                                 int d = r10_bio->devs[i].devnum;
3695                                 if (r10_bio->devs[i].bio->bi_end_io)
3696                                         rdev_dec_pending(conf->mirrors[d].rdev,
3697                                                          mddev);
3698                                 if (r10_bio->devs[i].repl_bio &&
3699                                     r10_bio->devs[i].repl_bio->bi_end_io)
3700                                         rdev_dec_pending(
3701                                                 conf->mirrors[d].replacement,
3702                                                 mddev);
3703                         }
3704                         put_buf(r10_bio);
3705                         biolist = NULL;
3706                         goto giveup;
3707                 }
3708         }
3709
3710         nr_sectors = 0;
3711         if (sector_nr + max_sync < max_sector)
3712                 max_sector = sector_nr + max_sync;
3713         do {
3714                 struct page *page;
3715                 int len = PAGE_SIZE;
3716                 if (sector_nr + (len>>9) > max_sector)
3717                         len = (max_sector - sector_nr) << 9;
3718                 if (len == 0)
3719                         break;
3720                 for (bio= biolist ; bio ; bio=bio->bi_next) {
3721                         struct resync_pages *rp = get_resync_pages(bio);
3722                         page = resync_fetch_page(rp, page_idx);
3723                         /*
3724                          * won't fail because the vec table is big enough
3725                          * to hold all these pages
3726                          */
3727                         bio_add_page(bio, page, len, 0);
3728                 }
3729                 nr_sectors += len>>9;
3730                 sector_nr += len>>9;
3731         } while (++page_idx < RESYNC_PAGES);
3732         r10_bio->sectors = nr_sectors;
3733
3734         if (mddev_is_clustered(mddev) &&
3735             test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
3736                 /* It is resync not recovery */
3737                 if (conf->cluster_sync_high < sector_nr + nr_sectors) {
3738                         conf->cluster_sync_low = mddev->curr_resync_completed;
3739                         raid10_set_cluster_sync_high(conf);
3740                         /* Send resync message */
3741                         md_cluster_ops->resync_info_update(mddev,
3742                                                 conf->cluster_sync_low,
3743                                                 conf->cluster_sync_high);
3744                 }
3745         } else if (mddev_is_clustered(mddev)) {
3746                 /* This is recovery not resync */
3747                 sector_t sect_va1, sect_va2;
3748                 bool broadcast_msg = false;
3749
3750                 for (i = 0; i < conf->geo.raid_disks; i++) {
3751                         /*
3752                          * sector_nr is a device address for recovery, so we
3753                          * need translate it to array address before compare
3754                          * with cluster_sync_high.
3755                          */
3756                         sect_va1 = raid10_find_virt(conf, sector_nr, i);
3757
3758                         if (conf->cluster_sync_high < sect_va1 + nr_sectors) {
3759                                 broadcast_msg = true;
3760                                 /*
3761                                  * curr_resync_completed is similar as
3762                                  * sector_nr, so make the translation too.
3763                                  */
3764                                 sect_va2 = raid10_find_virt(conf,
3765                                         mddev->curr_resync_completed, i);
3766
3767                                 if (conf->cluster_sync_low == 0 ||
3768                                     conf->cluster_sync_low > sect_va2)
3769                                         conf->cluster_sync_low = sect_va2;
3770                         }
3771                 }
3772                 if (broadcast_msg) {
3773                         raid10_set_cluster_sync_high(conf);
3774                         md_cluster_ops->resync_info_update(mddev,
3775                                                 conf->cluster_sync_low,
3776                                                 conf->cluster_sync_high);
3777                 }
3778         }
3779
3780         while (biolist) {
3781                 bio = biolist;
3782                 biolist = biolist->bi_next;
3783
3784                 bio->bi_next = NULL;
3785                 r10_bio = get_resync_r10bio(bio);
3786                 r10_bio->sectors = nr_sectors;
3787
3788                 if (bio->bi_end_io == end_sync_read) {
3789                         md_sync_acct_bio(bio, nr_sectors);
3790                         bio->bi_status = 0;
3791                         submit_bio_noacct(bio);
3792                 }
3793         }
3794
3795         if (sectors_skipped)
3796                 /* pretend they weren't skipped, it makes
3797                  * no important difference in this case
3798                  */
3799                 md_done_sync(mddev, sectors_skipped, 1);
3800
3801         return sectors_skipped + nr_sectors;
3802  giveup:
3803         /* There is nowhere to write, so all non-sync
3804          * drives must be failed or in resync, all drives
3805          * have a bad block, so try the next chunk...
3806          */
3807         if (sector_nr + max_sync < max_sector)
3808                 max_sector = sector_nr + max_sync;
3809
3810         sectors_skipped += (max_sector - sector_nr);
3811         chunks_skipped ++;
3812         sector_nr = max_sector;
3813         goto skipped;
3814 }
3815
3816 static sector_t
3817 raid10_size(struct mddev *mddev, sector_t sectors, int raid_disks)
3818 {
3819         sector_t size;
3820         struct r10conf *conf = mddev->private;
3821
3822         if (!raid_disks)
3823                 raid_disks = min(conf->geo.raid_disks,
3824                                  conf->prev.raid_disks);
3825         if (!sectors)
3826                 sectors = conf->dev_sectors;
3827
3828         size = sectors >> conf->geo.chunk_shift;
3829         sector_div(size, conf->geo.far_copies);
3830         size = size * raid_disks;
3831         sector_div(size, conf->geo.near_copies);
3832
3833         return size << conf->geo.chunk_shift;
3834 }
3835
3836 static void calc_sectors(struct r10conf *conf, sector_t size)
3837 {
3838         /* Calculate the number of sectors-per-device that will
3839          * actually be used, and set conf->dev_sectors and
3840          * conf->stride
3841          */
3842
3843         size = size >> conf->geo.chunk_shift;
3844         sector_div(size, conf->geo.far_copies);
3845         size = size * conf->geo.raid_disks;
3846         sector_div(size, conf->geo.near_copies);
3847         /* 'size' is now the number of chunks in the array */
3848         /* calculate "used chunks per device" */
3849         size = size * conf->copies;
3850
3851         /* We need to round up when dividing by raid_disks to
3852          * get the stride size.
3853          */
3854         size = DIV_ROUND_UP_SECTOR_T(size, conf->geo.raid_disks);
3855
3856         conf->dev_sectors = size << conf->geo.chunk_shift;
3857
3858         if (conf->geo.far_offset)
3859                 conf->geo.stride = 1 << conf->geo.chunk_shift;
3860         else {
3861                 sector_div(size, conf->geo.far_copies);
3862                 conf->geo.stride = size << conf->geo.chunk_shift;
3863         }
3864 }
3865
3866 enum geo_type {geo_new, geo_old, geo_start};
3867 static int setup_geo(struct geom *geo, struct mddev *mddev, enum geo_type new)
3868 {
3869         int nc, fc, fo;
3870         int layout, chunk, disks;
3871         switch (new) {
3872         case geo_old:
3873                 layout = mddev->layout;
3874                 chunk = mddev->chunk_sectors;
3875                 disks = mddev->raid_disks - mddev->delta_disks;
3876                 break;
3877         case geo_new:
3878                 layout = mddev->new_layout;
3879                 chunk = mddev->new_chunk_sectors;
3880                 disks = mddev->raid_disks;
3881                 break;
3882         default: /* avoid 'may be unused' warnings */
3883         case geo_start: /* new when starting reshape - raid_disks not
3884                          * updated yet. */
3885                 layout = mddev->new_layout;
3886                 chunk = mddev->new_chunk_sectors;
3887                 disks = mddev->raid_disks + mddev->delta_disks;
3888                 break;
3889         }
3890         if (layout >> 19)
3891                 return -1;
3892         if (chunk < (PAGE_SIZE >> 9) ||
3893             !is_power_of_2(chunk))
3894                 return -2;
3895         nc = layout & 255;
3896         fc = (layout >> 8) & 255;
3897         fo = layout & (1<<16);
3898         geo->raid_disks = disks;
3899         geo->near_copies = nc;
3900         geo->far_copies = fc;
3901         geo->far_offset = fo;
3902         switch (layout >> 17) {
3903         case 0: /* original layout.  simple but not always optimal */
3904                 geo->far_set_size = disks;
3905                 break;
3906         case 1: /* "improved" layout which was buggy.  Hopefully no-one is
3907                  * actually using this, but leave code here just in case.*/
3908                 geo->far_set_size = disks/fc;
3909                 WARN(geo->far_set_size < fc,
3910                      "This RAID10 layout does not provide data safety - please backup and create new array\n");
3911                 break;
3912         case 2: /* "improved" layout fixed to match documentation */
3913                 geo->far_set_size = fc * nc;
3914                 break;
3915         default: /* Not a valid layout */
3916                 return -1;
3917         }
3918         geo->chunk_mask = chunk - 1;
3919         geo->chunk_shift = ffz(~chunk);
3920         return nc*fc;
3921 }
3922
3923 static struct r10conf *setup_conf(struct mddev *mddev)
3924 {
3925         struct r10conf *conf = NULL;
3926         int err = -EINVAL;
3927         struct geom geo;
3928         int copies;
3929
3930         copies = setup_geo(&geo, mddev, geo_new);
3931
3932         if (copies == -2) {
3933                 pr_warn("md/raid10:%s: chunk size must be at least PAGE_SIZE(%ld) and be a power of 2.\n",
3934                         mdname(mddev), PAGE_SIZE);
3935                 goto out;
3936         }
3937
3938         if (copies < 2 || copies > mddev->raid_disks) {
3939                 pr_warn("md/raid10:%s: unsupported raid10 layout: 0x%8x\n",
3940                         mdname(mddev), mddev->new_layout);
3941                 goto out;
3942         }
3943
3944         err = -ENOMEM;
3945         conf = kzalloc(sizeof(struct r10conf), GFP_KERNEL);
3946         if (!conf)
3947                 goto out;
3948
3949         /* FIXME calc properly */
3950         conf->mirrors = kcalloc(mddev->raid_disks + max(0, -mddev->delta_disks),
3951                                 sizeof(struct raid10_info),
3952                                 GFP_KERNEL);
3953         if (!conf->mirrors)
3954                 goto out;
3955
3956         conf->tmppage = alloc_page(GFP_KERNEL);
3957         if (!conf->tmppage)
3958                 goto out;
3959
3960         conf->geo = geo;
3961         conf->copies = copies;
3962         err = mempool_init(&conf->r10bio_pool, NR_RAID_BIOS, r10bio_pool_alloc,
3963                            rbio_pool_free, conf);
3964         if (err)
3965                 goto out;
3966
3967         err = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
3968         if (err)
3969                 goto out;
3970
3971         calc_sectors(conf, mddev->dev_sectors);
3972         if (mddev->reshape_position == MaxSector) {
3973                 conf->prev = conf->geo;
3974                 conf->reshape_progress = MaxSector;
3975         } else {
3976                 if (setup_geo(&conf->prev, mddev, geo_old) != conf->copies) {
3977                         err = -EINVAL;
3978                         goto out;
3979                 }
3980                 conf->reshape_progress = mddev->reshape_position;
3981                 if (conf->prev.far_offset)
3982                         conf->prev.stride = 1 << conf->prev.chunk_shift;
3983                 else
3984                         /* far_copies must be 1 */
3985                         conf->prev.stride = conf->dev_sectors;
3986         }
3987         conf->reshape_safe = conf->reshape_progress;
3988         spin_lock_init(&conf->device_lock);
3989         INIT_LIST_HEAD(&conf->retry_list);
3990         INIT_LIST_HEAD(&conf->bio_end_io_list);
3991
3992         spin_lock_init(&conf->resync_lock);
3993         init_waitqueue_head(&conf->wait_barrier);
3994         atomic_set(&conf->nr_pending, 0);
3995
3996         err = -ENOMEM;
3997         conf->thread = md_register_thread(raid10d, mddev, "raid10");
3998         if (!conf->thread)
3999                 goto out;
4000
4001         conf->mddev = mddev;
4002         return conf;
4003
4004  out:
4005         if (conf) {
4006                 mempool_exit(&conf->r10bio_pool);
4007                 kfree(conf->mirrors);
4008                 safe_put_page(conf->tmppage);
4009                 bioset_exit(&conf->bio_split);
4010                 kfree(conf);
4011         }
4012         return ERR_PTR(err);
4013 }
4014
4015 static void raid10_set_io_opt(struct r10conf *conf)
4016 {
4017         int raid_disks = conf->geo.raid_disks;
4018
4019         if (!(conf->geo.raid_disks % conf->geo.near_copies))
4020                 raid_disks /= conf->geo.near_copies;
4021         blk_queue_io_opt(conf->mddev->queue, (conf->mddev->chunk_sectors << 9) *
4022                          raid_disks);
4023 }
4024
4025 static int raid10_run(struct mddev *mddev)
4026 {
4027         struct r10conf *conf;
4028         int i, disk_idx;
4029         struct raid10_info *disk;
4030         struct md_rdev *rdev;
4031         sector_t size;
4032         sector_t min_offset_diff = 0;
4033         int first = 1;
4034         bool discard_supported = false;
4035
4036         if (mddev_init_writes_pending(mddev) < 0)
4037                 return -ENOMEM;
4038
4039         if (mddev->private == NULL) {
4040                 conf = setup_conf(mddev);
4041                 if (IS_ERR(conf))
4042                         return PTR_ERR(conf);
4043                 mddev->private = conf;
4044         }
4045         conf = mddev->private;
4046         if (!conf)
4047                 goto out;
4048
4049         if (mddev_is_clustered(conf->mddev)) {
4050                 int fc, fo;
4051
4052                 fc = (mddev->layout >> 8) & 255;
4053                 fo = mddev->layout & (1<<16);
4054                 if (fc > 1 || fo > 0) {
4055                         pr_err("only near layout is supported by clustered"
4056                                 " raid10\n");
4057                         goto out_free_conf;
4058                 }
4059         }
4060
4061         mddev->thread = conf->thread;
4062         conf->thread = NULL;
4063
4064         if (mddev->queue) {
4065                 blk_queue_max_discard_sectors(mddev->queue,
4066                                               UINT_MAX);
4067                 blk_queue_max_write_same_sectors(mddev->queue, 0);
4068                 blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
4069                 blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
4070                 raid10_set_io_opt(conf);
4071         }
4072
4073         rdev_for_each(rdev, mddev) {
4074                 long long diff;
4075
4076                 disk_idx = rdev->raid_disk;
4077                 if (disk_idx < 0)
4078                         continue;
4079                 if (disk_idx >= conf->geo.raid_disks &&
4080                     disk_idx >= conf->prev.raid_disks)
4081                         continue;
4082                 disk = conf->mirrors + disk_idx;
4083
4084                 if (test_bit(Replacement, &rdev->flags)) {
4085                         if (disk->replacement)
4086                                 goto out_free_conf;
4087                         disk->replacement = rdev;
4088                 } else {
4089                         if (disk->rdev)
4090                                 goto out_free_conf;
4091                         disk->rdev = rdev;
4092                 }
4093                 diff = (rdev->new_data_offset - rdev->data_offset);
4094                 if (!mddev->reshape_backwards)
4095                         diff = -diff;
4096                 if (diff < 0)
4097                         diff = 0;
4098                 if (first || diff < min_offset_diff)
4099                         min_offset_diff = diff;
4100
4101                 if (mddev->gendisk)
4102                         disk_stack_limits(mddev->gendisk, rdev->bdev,
4103                                           rdev->data_offset << 9);
4104
4105                 disk->head_position = 0;
4106
4107                 if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
4108                         discard_supported = true;
4109                 first = 0;
4110         }
4111
4112         if (mddev->queue) {
4113                 if (discard_supported)
4114                         blk_queue_flag_set(QUEUE_FLAG_DISCARD,
4115                                                 mddev->queue);
4116                 else
4117                         blk_queue_flag_clear(QUEUE_FLAG_DISCARD,
4118                                                   mddev->queue);
4119         }
4120         /* need to check that every block has at least one working mirror */
4121         if (!enough(conf, -1)) {
4122                 pr_err("md/raid10:%s: not enough operational mirrors.\n",
4123                        mdname(mddev));
4124                 goto out_free_conf;
4125         }
4126
4127         if (conf->reshape_progress != MaxSector) {
4128                 /* must ensure that shape change is supported */
4129                 if (conf->geo.far_copies != 1 &&
4130                     conf->geo.far_offset == 0)
4131                         goto out_free_conf;
4132                 if (conf->prev.far_copies != 1 &&
4133                     conf->prev.far_offset == 0)
4134                         goto out_free_conf;
4135         }
4136
4137         mddev->degraded = 0;
4138         for (i = 0;
4139              i < conf->geo.raid_disks
4140                      || i < conf->prev.raid_disks;
4141              i++) {
4142
4143                 disk = conf->mirrors + i;
4144
4145                 if (!disk->rdev && disk->replacement) {
4146                         /* The replacement is all we have - use it */
4147                         disk->rdev = disk->replacement;
4148                         disk->replacement = NULL;
4149                         clear_bit(Replacement, &disk->rdev->flags);
4150                 }
4151
4152                 if (!disk->rdev ||
4153                     !test_bit(In_sync, &disk->rdev->flags)) {
4154                         disk->head_position = 0;
4155                         mddev->degraded++;
4156                         if (disk->rdev &&
4157                             disk->rdev->saved_raid_disk < 0)
4158                                 conf->fullsync = 1;
4159                 }
4160
4161                 if (disk->replacement &&
4162                     !test_bit(In_sync, &disk->replacement->flags) &&
4163                     disk->replacement->saved_raid_disk < 0) {
4164                         conf->fullsync = 1;
4165                 }
4166
4167                 disk->recovery_disabled = mddev->recovery_disabled - 1;
4168         }
4169
4170         if (mddev->recovery_cp != MaxSector)
4171                 pr_notice("md/raid10:%s: not clean -- starting background reconstruction\n",
4172                           mdname(mddev));
4173         pr_info("md/raid10:%s: active with %d out of %d devices\n",
4174                 mdname(mddev), conf->geo.raid_disks - mddev->degraded,
4175                 conf->geo.raid_disks);
4176         /*
4177          * Ok, everything is just fine now
4178          */
4179         mddev->dev_sectors = conf->dev_sectors;
4180         size = raid10_size(mddev, 0, 0);
4181         md_set_array_sectors(mddev, size);
4182         mddev->resync_max_sectors = size;
4183         set_bit(MD_FAILFAST_SUPPORTED, &mddev->flags);
4184
4185         if (md_integrity_register(mddev))
4186                 goto out_free_conf;
4187
4188         if (conf->reshape_progress != MaxSector) {
4189                 unsigned long before_length, after_length;
4190
4191                 before_length = ((1 << conf->prev.chunk_shift) *
4192                                  conf->prev.far_copies);
4193                 after_length = ((1 << conf->geo.chunk_shift) *
4194                                 conf->geo.far_copies);
4195
4196                 if (max(before_length, after_length) > min_offset_diff) {
4197                         /* This cannot work */
4198                         pr_warn("md/raid10: offset difference not enough to continue reshape\n");
4199                         goto out_free_conf;
4200                 }
4201                 conf->offset_diff = min_offset_diff;
4202
4203                 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4204                 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
4205                 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
4206                 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
4207                 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
4208                                                         "reshape");
4209                 if (!mddev->sync_thread)
4210                         goto out_free_conf;
4211         }
4212
4213         return 0;
4214
4215 out_free_conf:
4216         md_unregister_thread(&mddev->thread);
4217         mempool_exit(&conf->r10bio_pool);
4218         safe_put_page(conf->tmppage);
4219         kfree(conf->mirrors);
4220         kfree(conf);
4221         mddev->private = NULL;
4222 out:
4223         return -EIO;
4224 }
4225
4226 static void raid10_free(struct mddev *mddev, void *priv)
4227 {
4228         struct r10conf *conf = priv;
4229
4230         mempool_exit(&conf->r10bio_pool);
4231         safe_put_page(conf->tmppage);
4232         kfree(conf->mirrors);
4233         kfree(conf->mirrors_old);
4234         kfree(conf->mirrors_new);
4235         bioset_exit(&conf->bio_split);
4236         kfree(conf);
4237 }
4238
4239 static void raid10_quiesce(struct mddev *mddev, int quiesce)
4240 {
4241         struct r10conf *conf = mddev->private;
4242
4243         if (quiesce)
4244                 raise_barrier(conf, 0);
4245         else
4246                 lower_barrier(conf);
4247 }
4248
4249 static int raid10_resize(struct mddev *mddev, sector_t sectors)
4250 {
4251         /* Resize of 'far' arrays is not supported.
4252          * For 'near' and 'offset' arrays we can set the
4253          * number of sectors used to be an appropriate multiple
4254          * of the chunk size.
4255          * For 'offset', this is far_copies*chunksize.
4256          * For 'near' the multiplier is the LCM of
4257          * near_copies and raid_disks.
4258          * So if far_copies > 1 && !far_offset, fail.
4259          * Else find LCM(raid_disks, near_copy)*far_copies and
4260          * multiply by chunk_size.  Then round to this number.
4261          * This is mostly done by raid10_size()
4262          */
4263         struct r10conf *conf = mddev->private;
4264         sector_t oldsize, size;
4265
4266         if (mddev->reshape_position != MaxSector)
4267                 return -EBUSY;
4268
4269         if (conf->geo.far_copies > 1 && !conf->geo.far_offset)
4270                 return -EINVAL;
4271
4272         oldsize = raid10_size(mddev, 0, 0);
4273         size = raid10_size(mddev, sectors, 0);
4274         if (mddev->external_size &&
4275             mddev->array_sectors > size)
4276                 return -EINVAL;
4277         if (mddev->bitmap) {
4278                 int ret = md_bitmap_resize(mddev->bitmap, size, 0, 0);
4279                 if (ret)
4280                         return ret;
4281         }
4282         md_set_array_sectors(mddev, size);
4283         if (sectors > mddev->dev_sectors &&
4284             mddev->recovery_cp > oldsize) {
4285                 mddev->recovery_cp = oldsize;
4286                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4287         }
4288         calc_sectors(conf, sectors);
4289         mddev->dev_sectors = conf->dev_sectors;
4290         mddev->resync_max_sectors = size;
4291         return 0;
4292 }
4293
4294 static void *raid10_takeover_raid0(struct mddev *mddev, sector_t size, int devs)
4295 {
4296         struct md_rdev *rdev;
4297         struct r10conf *conf;
4298
4299         if (mddev->degraded > 0) {
4300                 pr_warn("md/raid10:%s: Error: degraded raid0!\n",
4301                         mdname(mddev));
4302                 return ERR_PTR(-EINVAL);
4303         }
4304         sector_div(size, devs);
4305
4306         /* Set new parameters */
4307         mddev->new_level = 10;
4308         /* new layout: far_copies = 1, near_copies = 2 */
4309         mddev->new_layout = (1<<8) + 2;
4310         mddev->new_chunk_sectors = mddev->chunk_sectors;
4311         mddev->delta_disks = mddev->raid_disks;
4312         mddev->raid_disks *= 2;
4313         /* make sure it will be not marked as dirty */
4314         mddev->recovery_cp = MaxSector;
4315         mddev->dev_sectors = size;
4316
4317         conf = setup_conf(mddev);
4318         if (!IS_ERR(conf)) {
4319                 rdev_for_each(rdev, mddev)
4320                         if (rdev->raid_disk >= 0) {
4321                                 rdev->new_raid_disk = rdev->raid_disk * 2;
4322                                 rdev->sectors = size;
4323                         }
4324                 conf->barrier = 1;
4325         }
4326
4327         return conf;
4328 }
4329
4330 static void *raid10_takeover(struct mddev *mddev)
4331 {
4332         struct r0conf *raid0_conf;
4333
4334         /* raid10 can take over:
4335          *  raid0 - providing it has only two drives
4336          */
4337         if (mddev->level == 0) {
4338                 /* for raid0 takeover only one zone is supported */
4339                 raid0_conf = mddev->private;
4340                 if (raid0_conf->nr_strip_zones > 1) {
4341                         pr_warn("md/raid10:%s: cannot takeover raid 0 with more than one zone.\n",
4342                                 mdname(mddev));
4343                         return ERR_PTR(-EINVAL);
4344                 }
4345                 return raid10_takeover_raid0(mddev,
4346                         raid0_conf->strip_zone->zone_end,
4347                         raid0_conf->strip_zone->nb_dev);
4348         }
4349         return ERR_PTR(-EINVAL);
4350 }
4351
4352 static int raid10_check_reshape(struct mddev *mddev)
4353 {
4354         /* Called when there is a request to change
4355          * - layout (to ->new_layout)
4356          * - chunk size (to ->new_chunk_sectors)
4357          * - raid_disks (by delta_disks)
4358          * or when trying to restart a reshape that was ongoing.
4359          *
4360          * We need to validate the request and possibly allocate
4361          * space if that might be an issue later.
4362          *
4363          * Currently we reject any reshape of a 'far' mode array,
4364          * allow chunk size to change if new is generally acceptable,
4365          * allow raid_disks to increase, and allow
4366          * a switch between 'near' mode and 'offset' mode.
4367          */
4368         struct r10conf *conf = mddev->private;
4369         struct geom geo;
4370
4371         if (conf->geo.far_copies != 1 && !conf->geo.far_offset)
4372                 return -EINVAL;
4373
4374         if (setup_geo(&geo, mddev, geo_start) != conf->copies)
4375                 /* mustn't change number of copies */
4376                 return -EINVAL;
4377         if (geo.far_copies > 1 && !geo.far_offset)
4378                 /* Cannot switch to 'far' mode */
4379                 return -EINVAL;
4380
4381         if (mddev->array_sectors & geo.chunk_mask)
4382                         /* not factor of array size */
4383                         return -EINVAL;
4384
4385         if (!enough(conf, -1))
4386                 return -EINVAL;
4387
4388         kfree(conf->mirrors_new);
4389         conf->mirrors_new = NULL;
4390         if (mddev->delta_disks > 0) {
4391                 /* allocate new 'mirrors' list */
4392                 conf->mirrors_new =
4393                         kcalloc(mddev->raid_disks + mddev->delta_disks,
4394                                 sizeof(struct raid10_info),
4395                                 GFP_KERNEL);
4396                 if (!conf->mirrors_new)
4397                         return -ENOMEM;
4398         }
4399         return 0;
4400 }
4401
4402 /*
4403  * Need to check if array has failed when deciding whether to:
4404  *  - start an array
4405  *  - remove non-faulty devices
4406  *  - add a spare
4407  *  - allow a reshape
4408  * This determination is simple when no reshape is happening.
4409  * However if there is a reshape, we need to carefully check
4410  * both the before and after sections.
4411  * This is because some failed devices may only affect one
4412  * of the two sections, and some non-in_sync devices may
4413  * be insync in the section most affected by failed devices.
4414  */
4415 static int calc_degraded(struct r10conf *conf)
4416 {
4417         int degraded, degraded2;
4418         int i;
4419
4420         rcu_read_lock();
4421         degraded = 0;
4422         /* 'prev' section first */
4423         for (i = 0; i < conf->prev.raid_disks; i++) {
4424                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
4425                 if (!rdev || test_bit(Faulty, &rdev->flags))
4426                         degraded++;
4427                 else if (!test_bit(In_sync, &rdev->flags))
4428                         /* When we can reduce the number of devices in
4429                          * an array, this might not contribute to
4430                          * 'degraded'.  It does now.
4431                          */
4432                         degraded++;
4433         }
4434         rcu_read_unlock();
4435         if (conf->geo.raid_disks == conf->prev.raid_disks)
4436                 return degraded;
4437         rcu_read_lock();
4438         degraded2 = 0;
4439         for (i = 0; i < conf->geo.raid_disks; i++) {
4440                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
4441                 if (!rdev || test_bit(Faulty, &rdev->flags))
4442                         degraded2++;
4443                 else if (!test_bit(In_sync, &rdev->flags)) {
4444                         /* If reshape is increasing the number of devices,
4445                          * this section has already been recovered, so
4446                          * it doesn't contribute to degraded.
4447                          * else it does.
4448                          */
4449                         if (conf->geo.raid_disks <= conf->prev.raid_disks)
4450                                 degraded2++;
4451                 }
4452         }
4453         rcu_read_unlock();
4454         if (degraded2 > degraded)
4455                 return degraded2;
4456         return degraded;
4457 }
4458
4459 static int raid10_start_reshape(struct mddev *mddev)
4460 {
4461         /* A 'reshape' has been requested. This commits
4462          * the various 'new' fields and sets MD_RECOVER_RESHAPE
4463          * This also checks if there are enough spares and adds them
4464          * to the array.
4465          * We currently require enough spares to make the final
4466          * array non-degraded.  We also require that the difference
4467          * between old and new data_offset - on each device - is
4468          * enough that we never risk over-writing.
4469          */
4470
4471         unsigned long before_length, after_length;
4472         sector_t min_offset_diff = 0;
4473         int first = 1;
4474         struct geom new;
4475         struct r10conf *conf = mddev->private;
4476         struct md_rdev *rdev;
4477         int spares = 0;
4478         int ret;
4479
4480         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
4481                 return -EBUSY;
4482
4483         if (setup_geo(&new, mddev, geo_start) != conf->copies)
4484                 return -EINVAL;
4485
4486         before_length = ((1 << conf->prev.chunk_shift) *
4487                          conf->prev.far_copies);
4488         after_length = ((1 << conf->geo.chunk_shift) *
4489                         conf->geo.far_copies);
4490
4491         rdev_for_each(rdev, mddev) {
4492                 if (!test_bit(In_sync, &rdev->flags)
4493                     && !test_bit(Faulty, &rdev->flags))
4494                         spares++;
4495                 if (rdev->raid_disk >= 0) {
4496                         long long diff = (rdev->new_data_offset
4497                                           - rdev->data_offset);
4498                         if (!mddev->reshape_backwards)
4499                                 diff = -diff;
4500                         if (diff < 0)
4501                                 diff = 0;
4502                         if (first || diff < min_offset_diff)
4503                                 min_offset_diff = diff;
4504                         first = 0;
4505                 }
4506         }
4507
4508         if (max(before_length, after_length) > min_offset_diff)
4509                 return -EINVAL;
4510
4511         if (spares < mddev->delta_disks)
4512                 return -EINVAL;
4513
4514         conf->offset_diff = min_offset_diff;
4515         spin_lock_irq(&conf->device_lock);
4516         if (conf->mirrors_new) {
4517                 memcpy(conf->mirrors_new, conf->mirrors,
4518                        sizeof(struct raid10_info)*conf->prev.raid_disks);
4519                 smp_mb();
4520                 kfree(conf->mirrors_old);
4521                 conf->mirrors_old = conf->mirrors;
4522                 conf->mirrors = conf->mirrors_new;
4523                 conf->mirrors_new = NULL;
4524         }
4525         setup_geo(&conf->geo, mddev, geo_start);
4526         smp_mb();
4527         if (mddev->reshape_backwards) {
4528                 sector_t size = raid10_size(mddev, 0, 0);
4529                 if (size < mddev->array_sectors) {
4530                         spin_unlock_irq(&conf->device_lock);
4531                         pr_warn("md/raid10:%s: array size must be reduce before number of disks\n",
4532                                 mdname(mddev));
4533                         return -EINVAL;
4534                 }
4535                 mddev->resync_max_sectors = size;
4536                 conf->reshape_progress = size;
4537         } else
4538                 conf->reshape_progress = 0;
4539         conf->reshape_safe = conf->reshape_progress;
4540         spin_unlock_irq(&conf->device_lock);
4541
4542         if (mddev->delta_disks && mddev->bitmap) {
4543                 struct mdp_superblock_1 *sb = NULL;
4544                 sector_t oldsize, newsize;
4545
4546                 oldsize = raid10_size(mddev, 0, 0);
4547                 newsize = raid10_size(mddev, 0, conf->geo.raid_disks);
4548
4549                 if (!mddev_is_clustered(mddev)) {
4550                         ret = md_bitmap_resize(mddev->bitmap, newsize, 0, 0);
4551                         if (ret)
4552                                 goto abort;
4553                         else
4554                                 goto out;
4555                 }
4556
4557                 rdev_for_each(rdev, mddev) {
4558                         if (rdev->raid_disk > -1 &&
4559                             !test_bit(Faulty, &rdev->flags))
4560                                 sb = page_address(rdev->sb_page);
4561                 }
4562
4563                 /*
4564                  * some node is already performing reshape, and no need to
4565                  * call md_bitmap_resize again since it should be called when
4566                  * receiving BITMAP_RESIZE msg
4567                  */
4568                 if ((sb && (le32_to_cpu(sb->feature_map) &
4569                             MD_FEATURE_RESHAPE_ACTIVE)) || (oldsize == newsize))
4570                         goto out;
4571
4572                 ret = md_bitmap_resize(mddev->bitmap, newsize, 0, 0);
4573                 if (ret)
4574                         goto abort;
4575
4576                 ret = md_cluster_ops->resize_bitmaps(mddev, newsize, oldsize);
4577                 if (ret) {
4578                         md_bitmap_resize(mddev->bitmap, oldsize, 0, 0);
4579                         goto abort;
4580                 }
4581         }
4582 out:
4583         if (mddev->delta_disks > 0) {
4584                 rdev_for_each(rdev, mddev)
4585                         if (rdev->raid_disk < 0 &&
4586                             !test_bit(Faulty, &rdev->flags)) {
4587                                 if (raid10_add_disk(mddev, rdev) == 0) {
4588                                         if (rdev->raid_disk >=
4589                                             conf->prev.raid_disks)
4590                                                 set_bit(In_sync, &rdev->flags);
4591                                         else
4592                                                 rdev->recovery_offset = 0;
4593
4594                                         /* Failure here is OK */
4595                                         sysfs_link_rdev(mddev, rdev);
4596                                 }
4597                         } else if (rdev->raid_disk >= conf->prev.raid_disks
4598                                    && !test_bit(Faulty, &rdev->flags)) {
4599                                 /* This is a spare that was manually added */
4600                                 set_bit(In_sync, &rdev->flags);
4601                         }
4602         }
4603         /* When a reshape changes the number of devices,
4604          * ->degraded is measured against the larger of the
4605          * pre and  post numbers.
4606          */
4607         spin_lock_irq(&conf->device_lock);
4608         mddev->degraded = calc_degraded(conf);
4609         spin_unlock_irq(&conf->device_lock);
4610         mddev->raid_disks = conf->geo.raid_disks;
4611         mddev->reshape_position = conf->reshape_progress;
4612         set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
4613
4614         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4615         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
4616         clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
4617         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
4618         set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
4619
4620         mddev->sync_thread = md_register_thread(md_do_sync, mddev,
4621                                                 "reshape");
4622         if (!mddev->sync_thread) {
4623                 ret = -EAGAIN;
4624                 goto abort;
4625         }
4626         conf->reshape_checkpoint = jiffies;
4627         md_wakeup_thread(mddev->sync_thread);
4628         md_new_event(mddev);
4629         return 0;
4630
4631 abort:
4632         mddev->recovery = 0;
4633         spin_lock_irq(&conf->device_lock);
4634         conf->geo = conf->prev;
4635         mddev->raid_disks = conf->geo.raid_disks;
4636         rdev_for_each(rdev, mddev)
4637                 rdev->new_data_offset = rdev->data_offset;
4638         smp_wmb();
4639         conf->reshape_progress = MaxSector;
4640         conf->reshape_safe = MaxSector;
4641         mddev->reshape_position = MaxSector;
4642         spin_unlock_irq(&conf->device_lock);
4643         return ret;
4644 }
4645
4646 /* Calculate the last device-address that could contain
4647  * any block from the chunk that includes the array-address 's'
4648  * and report the next address.
4649  * i.e. the address returned will be chunk-aligned and after
4650  * any data that is in the chunk containing 's'.
4651  */
4652 static sector_t last_dev_address(sector_t s, struct geom *geo)
4653 {
4654         s = (s | geo->chunk_mask) + 1;
4655         s >>= geo->chunk_shift;
4656         s *= geo->near_copies;
4657         s = DIV_ROUND_UP_SECTOR_T(s, geo->raid_disks);
4658         s *= geo->far_copies;
4659         s <<= geo->chunk_shift;
4660         return s;
4661 }
4662
4663 /* Calculate the first device-address that could contain
4664  * any block from the chunk that includes the array-address 's'.
4665  * This too will be the start of a chunk
4666  */
4667 static sector_t first_dev_address(sector_t s, struct geom *geo)
4668 {
4669         s >>= geo->chunk_shift;
4670         s *= geo->near_copies;
4671         sector_div(s, geo->raid_disks);
4672         s *= geo->far_copies;
4673         s <<= geo->chunk_shift;
4674         return s;
4675 }
4676
4677 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr,
4678                                 int *skipped)
4679 {
4680         /* We simply copy at most one chunk (smallest of old and new)
4681          * at a time, possibly less if that exceeds RESYNC_PAGES,
4682          * or we hit a bad block or something.
4683          * This might mean we pause for normal IO in the middle of
4684          * a chunk, but that is not a problem as mddev->reshape_position
4685          * can record any location.
4686          *
4687          * If we will want to write to a location that isn't
4688          * yet recorded as 'safe' (i.e. in metadata on disk) then
4689          * we need to flush all reshape requests and update the metadata.
4690          *
4691          * When reshaping forwards (e.g. to more devices), we interpret
4692          * 'safe' as the earliest block which might not have been copied
4693          * down yet.  We divide this by previous stripe size and multiply
4694          * by previous stripe length to get lowest device offset that we
4695          * cannot write to yet.
4696          * We interpret 'sector_nr' as an address that we want to write to.
4697          * From this we use last_device_address() to find where we might
4698          * write to, and first_device_address on the  'safe' position.
4699          * If this 'next' write position is after the 'safe' position,
4700          * we must update the metadata to increase the 'safe' position.
4701          *
4702          * When reshaping backwards, we round in the opposite direction
4703          * and perform the reverse test:  next write position must not be
4704          * less than current safe position.
4705          *
4706          * In all this the minimum difference in data offsets
4707          * (conf->offset_diff - always positive) allows a bit of slack,
4708          * so next can be after 'safe', but not by more than offset_diff
4709          *
4710          * We need to prepare all the bios here before we start any IO
4711          * to ensure the size we choose is acceptable to all devices.
4712          * The means one for each copy for write-out and an extra one for
4713          * read-in.
4714          * We store the read-in bio in ->master_bio and the others in
4715          * ->devs[x].bio and ->devs[x].repl_bio.
4716          */
4717         struct r10conf *conf = mddev->private;
4718         struct r10bio *r10_bio;
4719         sector_t next, safe, last;
4720         int max_sectors;
4721         int nr_sectors;
4722         int s;
4723         struct md_rdev *rdev;
4724         int need_flush = 0;
4725         struct bio *blist;
4726         struct bio *bio, *read_bio;
4727         int sectors_done = 0;
4728         struct page **pages;
4729
4730         if (sector_nr == 0) {
4731                 /* If restarting in the middle, skip the initial sectors */
4732                 if (mddev->reshape_backwards &&
4733                     conf->reshape_progress < raid10_size(mddev, 0, 0)) {
4734                         sector_nr = (raid10_size(mddev, 0, 0)
4735                                      - conf->reshape_progress);
4736                 } else if (!mddev->reshape_backwards &&
4737                            conf->reshape_progress > 0)
4738                         sector_nr = conf->reshape_progress;
4739                 if (sector_nr) {
4740                         mddev->curr_resync_completed = sector_nr;
4741                         sysfs_notify_dirent_safe(mddev->sysfs_completed);
4742                         *skipped = 1;
4743                         return sector_nr;
4744                 }
4745         }
4746
4747         /* We don't use sector_nr to track where we are up to
4748          * as that doesn't work well for ->reshape_backwards.
4749          * So just use ->reshape_progress.
4750          */
4751         if (mddev->reshape_backwards) {
4752                 /* 'next' is the earliest device address that we might
4753                  * write to for this chunk in the new layout
4754                  */
4755                 next = first_dev_address(conf->reshape_progress - 1,
4756                                          &conf->geo);
4757
4758                 /* 'safe' is the last device address that we might read from
4759                  * in the old layout after a restart
4760                  */
4761                 safe = last_dev_address(conf->reshape_safe - 1,
4762                                         &conf->prev);
4763
4764                 if (next + conf->offset_diff < safe)
4765                         need_flush = 1;
4766
4767                 last = conf->reshape_progress - 1;
4768                 sector_nr = last & ~(sector_t)(conf->geo.chunk_mask
4769                                                & conf->prev.chunk_mask);
4770                 if (sector_nr + RESYNC_SECTORS < last)
4771                         sector_nr = last + 1 - RESYNC_SECTORS;
4772         } else {
4773                 /* 'next' is after the last device address that we
4774                  * might write to for this chunk in the new layout
4775                  */
4776                 next = last_dev_address(conf->reshape_progress, &conf->geo);
4777
4778                 /* 'safe' is the earliest device address that we might
4779                  * read from in the old layout after a restart
4780                  */
4781                 safe = first_dev_address(conf->reshape_safe, &conf->prev);
4782
4783                 /* Need to update metadata if 'next' might be beyond 'safe'
4784                  * as that would possibly corrupt data
4785                  */
4786                 if (next > safe + conf->offset_diff)
4787                         need_flush = 1;
4788
4789                 sector_nr = conf->reshape_progress;
4790                 last  = sector_nr | (conf->geo.chunk_mask
4791                                      & conf->prev.chunk_mask);
4792
4793                 if (sector_nr + RESYNC_SECTORS <= last)
4794                         last = sector_nr + RESYNC_SECTORS - 1;
4795         }
4796
4797         if (need_flush ||
4798             time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
4799                 /* Need to update reshape_position in metadata */
4800                 wait_barrier(conf);
4801                 mddev->reshape_position = conf->reshape_progress;
4802                 if (mddev->reshape_backwards)
4803                         mddev->curr_resync_completed = raid10_size(mddev, 0, 0)
4804                                 - conf->reshape_progress;
4805                 else
4806                         mddev->curr_resync_completed = conf->reshape_progress;
4807                 conf->reshape_checkpoint = jiffies;
4808                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
4809                 md_wakeup_thread(mddev->thread);
4810                 wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
4811                            test_bit(MD_RECOVERY_INTR, &mddev->recovery));
4812                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
4813                         allow_barrier(conf);
4814                         return sectors_done;
4815                 }
4816                 conf->reshape_safe = mddev->reshape_position;
4817                 allow_barrier(conf);
4818         }
4819
4820         raise_barrier(conf, 0);
4821 read_more:
4822         /* Now schedule reads for blocks from sector_nr to last */
4823         r10_bio = raid10_alloc_init_r10buf(conf);
4824         r10_bio->state = 0;
4825         raise_barrier(conf, 1);
4826         atomic_set(&r10_bio->remaining, 0);
4827         r10_bio->mddev = mddev;
4828         r10_bio->sector = sector_nr;
4829         set_bit(R10BIO_IsReshape, &r10_bio->state);
4830         r10_bio->sectors = last - sector_nr + 1;
4831         rdev = read_balance(conf, r10_bio, &max_sectors);
4832         BUG_ON(!test_bit(R10BIO_Previous, &r10_bio->state));
4833
4834         if (!rdev) {
4835                 /* Cannot read from here, so need to record bad blocks
4836                  * on all the target devices.
4837                  */
4838                 // FIXME
4839                 mempool_free(r10_bio, &conf->r10buf_pool);
4840                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
4841                 return sectors_done;
4842         }
4843
4844         read_bio = bio_alloc_mddev(GFP_KERNEL, RESYNC_PAGES, mddev);
4845
4846         bio_set_dev(read_bio, rdev->bdev);
4847         read_bio->bi_iter.bi_sector = (r10_bio->devs[r10_bio->read_slot].addr
4848                                + rdev->data_offset);
4849         read_bio->bi_private = r10_bio;
4850         read_bio->bi_end_io = end_reshape_read;
4851         bio_set_op_attrs(read_bio, REQ_OP_READ, 0);
4852         read_bio->bi_flags &= (~0UL << BIO_RESET_BITS);
4853         read_bio->bi_status = 0;
4854         read_bio->bi_vcnt = 0;
4855         read_bio->bi_iter.bi_size = 0;
4856         r10_bio->master_bio = read_bio;
4857         r10_bio->read_slot = r10_bio->devs[r10_bio->read_slot].devnum;
4858
4859         /*
4860          * Broadcast RESYNC message to other nodes, so all nodes would not
4861          * write to the region to avoid conflict.
4862         */
4863         if (mddev_is_clustered(mddev) && conf->cluster_sync_high <= sector_nr) {
4864                 struct mdp_superblock_1 *sb = NULL;
4865                 int sb_reshape_pos = 0;
4866
4867                 conf->cluster_sync_low = sector_nr;
4868                 conf->cluster_sync_high = sector_nr + CLUSTER_RESYNC_WINDOW_SECTORS;
4869                 sb = page_address(rdev->sb_page);
4870                 if (sb) {
4871                         sb_reshape_pos = le64_to_cpu(sb->reshape_position);
4872                         /*
4873                          * Set cluster_sync_low again if next address for array
4874                          * reshape is less than cluster_sync_low. Since we can't
4875                          * update cluster_sync_low until it has finished reshape.
4876                          */
4877                         if (sb_reshape_pos < conf->cluster_sync_low)
4878                                 conf->cluster_sync_low = sb_reshape_pos;
4879                 }
4880
4881                 md_cluster_ops->resync_info_update(mddev, conf->cluster_sync_low,
4882                                                           conf->cluster_sync_high);
4883         }
4884
4885         /* Now find the locations in the new layout */
4886         __raid10_find_phys(&conf->geo, r10_bio);
4887
4888         blist = read_bio;
4889         read_bio->bi_next = NULL;
4890
4891         rcu_read_lock();
4892         for (s = 0; s < conf->copies*2; s++) {
4893                 struct bio *b;
4894                 int d = r10_bio->devs[s/2].devnum;
4895                 struct md_rdev *rdev2;
4896                 if (s&1) {
4897                         rdev2 = rcu_dereference(conf->mirrors[d].replacement);
4898                         b = r10_bio->devs[s/2].repl_bio;
4899                 } else {
4900                         rdev2 = rcu_dereference(conf->mirrors[d].rdev);
4901                         b = r10_bio->devs[s/2].bio;
4902                 }
4903                 if (!rdev2 || test_bit(Faulty, &rdev2->flags))
4904                         continue;
4905
4906                 bio_set_dev(b, rdev2->bdev);
4907                 b->bi_iter.bi_sector = r10_bio->devs[s/2].addr +
4908                         rdev2->new_data_offset;
4909                 b->bi_end_io = end_reshape_write;
4910                 bio_set_op_attrs(b, REQ_OP_WRITE, 0);
4911                 b->bi_next = blist;
4912                 blist = b;
4913         }
4914
4915         /* Now add as many pages as possible to all of these bios. */
4916
4917         nr_sectors = 0;
4918         pages = get_resync_pages(r10_bio->devs[0].bio)->pages;
4919         for (s = 0 ; s < max_sectors; s += PAGE_SIZE >> 9) {
4920                 struct page *page = pages[s / (PAGE_SIZE >> 9)];
4921                 int len = (max_sectors - s) << 9;
4922                 if (len > PAGE_SIZE)
4923                         len = PAGE_SIZE;
4924                 for (bio = blist; bio ; bio = bio->bi_next) {
4925                         /*
4926                          * won't fail because the vec table is big enough
4927                          * to hold all these pages
4928                          */
4929                         bio_add_page(bio, page, len, 0);
4930                 }
4931                 sector_nr += len >> 9;
4932                 nr_sectors += len >> 9;
4933         }
4934         rcu_read_unlock();
4935         r10_bio->sectors = nr_sectors;
4936
4937         /* Now submit the read */
4938         md_sync_acct_bio(read_bio, r10_bio->sectors);
4939         atomic_inc(&r10_bio->remaining);
4940         read_bio->bi_next = NULL;
4941         submit_bio_noacct(read_bio);
4942         sectors_done += nr_sectors;
4943         if (sector_nr <= last)
4944                 goto read_more;
4945
4946         lower_barrier(conf);
4947
4948         /* Now that we have done the whole section we can
4949          * update reshape_progress
4950          */
4951         if (mddev->reshape_backwards)
4952                 conf->reshape_progress -= sectors_done;
4953         else
4954                 conf->reshape_progress += sectors_done;
4955
4956         return sectors_done;
4957 }
4958
4959 static void end_reshape_request(struct r10bio *r10_bio);
4960 static int handle_reshape_read_error(struct mddev *mddev,
4961                                      struct r10bio *r10_bio);
4962 static void reshape_request_write(struct mddev *mddev, struct r10bio *r10_bio)
4963 {
4964         /* Reshape read completed.  Hopefully we have a block
4965          * to write out.
4966          * If we got a read error then we do sync 1-page reads from
4967          * elsewhere until we find the data - or give up.
4968          */
4969         struct r10conf *conf = mddev->private;
4970         int s;
4971
4972         if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
4973                 if (handle_reshape_read_error(mddev, r10_bio) < 0) {
4974                         /* Reshape has been aborted */
4975                         md_done_sync(mddev, r10_bio->sectors, 0);
4976                         return;
4977                 }
4978
4979         /* We definitely have the data in the pages, schedule the
4980          * writes.
4981          */
4982         atomic_set(&r10_bio->remaining, 1);
4983         for (s = 0; s < conf->copies*2; s++) {
4984                 struct bio *b;
4985                 int d = r10_bio->devs[s/2].devnum;
4986                 struct md_rdev *rdev;
4987                 rcu_read_lock();
4988                 if (s&1) {
4989                         rdev = rcu_dereference(conf->mirrors[d].replacement);
4990                         b = r10_bio->devs[s/2].repl_bio;
4991                 } else {
4992                         rdev = rcu_dereference(conf->mirrors[d].rdev);
4993                         b = r10_bio->devs[s/2].bio;
4994                 }
4995                 if (!rdev || test_bit(Faulty, &rdev->flags)) {
4996                         rcu_read_unlock();
4997                         continue;
4998                 }
4999                 atomic_inc(&rdev->nr_pending);
5000                 rcu_read_unlock();
5001                 md_sync_acct_bio(b, r10_bio->sectors);
5002                 atomic_inc(&r10_bio->remaining);
5003                 b->bi_next = NULL;
5004                 submit_bio_noacct(b);
5005         }
5006         end_reshape_request(r10_bio);
5007 }
5008
5009 static void end_reshape(struct r10conf *conf)
5010 {
5011         if (test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery))
5012                 return;
5013
5014         spin_lock_irq(&conf->device_lock);
5015         conf->prev = conf->geo;
5016         md_finish_reshape(conf->mddev);
5017         smp_wmb();
5018         conf->reshape_progress = MaxSector;
5019         conf->reshape_safe = MaxSector;
5020         spin_unlock_irq(&conf->device_lock);
5021
5022         if (conf->mddev->queue)
5023                 raid10_set_io_opt(conf);
5024         conf->fullsync = 0;
5025 }
5026
5027 static void raid10_update_reshape_pos(struct mddev *mddev)
5028 {
5029         struct r10conf *conf = mddev->private;
5030         sector_t lo, hi;
5031
5032         md_cluster_ops->resync_info_get(mddev, &lo, &hi);
5033         if (((mddev->reshape_position <= hi) && (mddev->reshape_position >= lo))
5034             || mddev->reshape_position == MaxSector)
5035                 conf->reshape_progress = mddev->reshape_position;
5036         else
5037                 WARN_ON_ONCE(1);
5038 }
5039
5040 static int handle_reshape_read_error(struct mddev *mddev,
5041                                      struct r10bio *r10_bio)
5042 {
5043         /* Use sync reads to get the blocks from somewhere else */
5044         int sectors = r10_bio->sectors;
5045         struct r10conf *conf = mddev->private;
5046         struct r10bio *r10b;
5047         int slot = 0;
5048         int idx = 0;
5049         struct page **pages;
5050
5051         r10b = kmalloc(struct_size(r10b, devs, conf->copies), GFP_NOIO);
5052         if (!r10b) {
5053                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
5054                 return -ENOMEM;
5055         }
5056
5057         /* reshape IOs share pages from .devs[0].bio */
5058         pages = get_resync_pages(r10_bio->devs[0].bio)->pages;
5059
5060         r10b->sector = r10_bio->sector;
5061         __raid10_find_phys(&conf->prev, r10b);
5062
5063         while (sectors) {
5064                 int s = sectors;
5065                 int success = 0;
5066                 int first_slot = slot;
5067
5068                 if (s > (PAGE_SIZE >> 9))
5069                         s = PAGE_SIZE >> 9;
5070
5071                 rcu_read_lock();
5072                 while (!success) {
5073                         int d = r10b->devs[slot].devnum;
5074                         struct md_rdev *rdev = rcu_dereference(conf->mirrors[d].rdev);
5075                         sector_t addr;
5076                         if (rdev == NULL ||
5077                             test_bit(Faulty, &rdev->flags) ||
5078                             !test_bit(In_sync, &rdev->flags))
5079                                 goto failed;
5080
5081                         addr = r10b->devs[slot].addr + idx * PAGE_SIZE;
5082                         atomic_inc(&rdev->nr_pending);
5083                         rcu_read_unlock();
5084                         success = sync_page_io(rdev,
5085                                                addr,
5086                                                s << 9,
5087                                                pages[idx],
5088                                                REQ_OP_READ, 0, false);
5089                         rdev_dec_pending(rdev, mddev);
5090                         rcu_read_lock();
5091                         if (success)
5092                                 break;
5093                 failed:
5094                         slot++;
5095                         if (slot >= conf->copies)
5096                                 slot = 0;
5097                         if (slot == first_slot)
5098                                 break;
5099                 }
5100                 rcu_read_unlock();
5101                 if (!success) {
5102                         /* couldn't read this block, must give up */
5103                         set_bit(MD_RECOVERY_INTR,
5104                                 &mddev->recovery);
5105                         kfree(r10b);
5106                         return -EIO;
5107                 }
5108                 sectors -= s;
5109                 idx++;
5110         }
5111         kfree(r10b);
5112         return 0;
5113 }
5114
5115 static void end_reshape_write(struct bio *bio)
5116 {
5117         struct r10bio *r10_bio = get_resync_r10bio(bio);
5118         struct mddev *mddev = r10_bio->mddev;
5119         struct r10conf *conf = mddev->private;
5120         int d;
5121         int slot;
5122         int repl;
5123         struct md_rdev *rdev = NULL;
5124
5125         d = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
5126         if (repl)
5127                 rdev = conf->mirrors[d].replacement;
5128         if (!rdev) {
5129                 smp_mb();
5130                 rdev = conf->mirrors[d].rdev;
5131         }
5132
5133         if (bio->bi_status) {
5134                 /* FIXME should record badblock */
5135                 md_error(mddev, rdev);
5136         }
5137
5138         rdev_dec_pending(rdev, mddev);
5139         end_reshape_request(r10_bio);
5140 }
5141
5142 static void end_reshape_request(struct r10bio *r10_bio)
5143 {
5144         if (!atomic_dec_and_test(&r10_bio->remaining))
5145                 return;
5146         md_done_sync(r10_bio->mddev, r10_bio->sectors, 1);
5147         bio_put(r10_bio->master_bio);
5148         put_buf(r10_bio);
5149 }
5150
5151 static void raid10_finish_reshape(struct mddev *mddev)
5152 {
5153         struct r10conf *conf = mddev->private;
5154
5155         if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5156                 return;
5157
5158         if (mddev->delta_disks > 0) {
5159                 if (mddev->recovery_cp > mddev->resync_max_sectors) {
5160                         mddev->recovery_cp = mddev->resync_max_sectors;
5161                         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5162                 }
5163                 mddev->resync_max_sectors = mddev->array_sectors;
5164         } else {
5165                 int d;
5166                 rcu_read_lock();
5167                 for (d = conf->geo.raid_disks ;
5168                      d < conf->geo.raid_disks - mddev->delta_disks;
5169                      d++) {
5170                         struct md_rdev *rdev = rcu_dereference(conf->mirrors[d].rdev);
5171                         if (rdev)
5172                                 clear_bit(In_sync, &rdev->flags);
5173                         rdev = rcu_dereference(conf->mirrors[d].replacement);
5174                         if (rdev)
5175                                 clear_bit(In_sync, &rdev->flags);
5176                 }
5177                 rcu_read_unlock();
5178         }
5179         mddev->layout = mddev->new_layout;
5180         mddev->chunk_sectors = 1 << conf->geo.chunk_shift;
5181         mddev->reshape_position = MaxSector;
5182         mddev->delta_disks = 0;
5183         mddev->reshape_backwards = 0;
5184 }
5185
5186 static struct md_personality raid10_personality =
5187 {
5188         .name           = "raid10",
5189         .level          = 10,
5190         .owner          = THIS_MODULE,
5191         .make_request   = raid10_make_request,
5192         .run            = raid10_run,
5193         .free           = raid10_free,
5194         .status         = raid10_status,
5195         .error_handler  = raid10_error,
5196         .hot_add_disk   = raid10_add_disk,
5197         .hot_remove_disk= raid10_remove_disk,
5198         .spare_active   = raid10_spare_active,
5199         .sync_request   = raid10_sync_request,
5200         .quiesce        = raid10_quiesce,
5201         .size           = raid10_size,
5202         .resize         = raid10_resize,
5203         .takeover       = raid10_takeover,
5204         .check_reshape  = raid10_check_reshape,
5205         .start_reshape  = raid10_start_reshape,
5206         .finish_reshape = raid10_finish_reshape,
5207         .update_reshape_pos = raid10_update_reshape_pos,
5208 };
5209
5210 static int __init raid_init(void)
5211 {
5212         return register_md_personality(&raid10_personality);
5213 }
5214
5215 static void raid_exit(void)
5216 {
5217         unregister_md_personality(&raid10_personality);
5218 }
5219
5220 module_init(raid_init);
5221 module_exit(raid_exit);
5222 MODULE_LICENSE("GPL");
5223 MODULE_DESCRIPTION("RAID10 (striped mirror) personality for MD");
5224 MODULE_ALIAS("md-personality-9"); /* RAID10 */
5225 MODULE_ALIAS("md-raid10");
5226 MODULE_ALIAS("md-level-10");
5227
5228 module_param(max_queued_requests, int, S_IRUGO|S_IWUSR);