drivers/md/raid1.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * raid1.c : Multiple Devices driver for Linux
   4  *
   5  * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat
   6  *
   7  * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman
   8  *
   9  * RAID-1 management functions.
  10  *
  11  * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000
  12  *
  13  * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
  14  * Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
  15  *
  16  * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support
  17  * bitmapped intelligence in resync:
  18  *
  19  *      - bitmap marked during normal i/o
  20  *      - bitmap used to skip nondirty blocks during sync
  21  *
  22  * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology:
  23  * - persistent bitmap code
  24  */
  25
  26 #include <linux/slab.h>
  27 #include <linux/delay.h>
  28 #include <linux/blkdev.h>
  29 #include <linux/module.h>
  30 #include <linux/seq_file.h>
  31 #include <linux/ratelimit.h>
  32 #include <linux/interval_tree_generic.h>
  33
  34 #include <trace/events/block.h>
  35
  36 #include "md.h"
  37 #include "raid1.h"
  38 #include "md-bitmap.h"
  39
  40 #define UNSUPPORTED_MDDEV_FLAGS         \
  41         ((1L << MD_HAS_JOURNAL) |       \
  42          (1L << MD_JOURNAL_CLEAN) |     \
  43          (1L << MD_HAS_PPL) |           \
  44          (1L << MD_HAS_MULTIPLE_PPLS))
  45
  46 static void allow_barrier(struct r1conf *conf, sector_t sector_nr);
  47 static void lower_barrier(struct r1conf *conf, sector_t sector_nr);
  48
  49 #define raid1_log(md, fmt, args...)                             \
  50         do { if ((md)->queue) blk_add_trace_msg((md)->queue, "raid1 " fmt, ##args); } while (0)
  51
  52 #include "raid1-10.c"
  53
  54 #define START(node) ((node)->start)
  55 #define LAST(node) ((node)->last)
  56 INTERVAL_TREE_DEFINE(struct serial_info, node, sector_t, _subtree_last,
  57                      START, LAST, static inline, raid1_rb);
  58
  59 static int check_and_add_serial(struct md_rdev *rdev, struct r1bio *r1_bio,
  60                                 struct serial_info *si, int idx)
  61 {
  62         unsigned long flags;
  63         int ret = 0;
  64         sector_t lo = r1_bio->sector;
  65         sector_t hi = lo + r1_bio->sectors;
  66         struct serial_in_rdev *serial = &rdev->serial[idx];
  67
  68         spin_lock_irqsave(&serial->serial_lock, flags);
  69         /* collision happened */
  70         if (raid1_rb_iter_first(&serial->serial_rb, lo, hi))
  71                 ret = -EBUSY;
  72         else {
  73                 si->start = lo;
  74                 si->last = hi;
  75                 raid1_rb_insert(si, &serial->serial_rb);
  76         }
  77         spin_unlock_irqrestore(&serial->serial_lock, flags);
  78
  79         return ret;
  80 }
  81
  82 static void wait_for_serialization(struct md_rdev *rdev, struct r1bio *r1_bio)
  83 {
  84         struct mddev *mddev = rdev->mddev;
  85         struct serial_info *si;
  86         int idx = sector_to_idx(r1_bio->sector);
  87         struct serial_in_rdev *serial = &rdev->serial[idx];
  88
  89         if (WARN_ON(!mddev->serial_info_pool))
  90                 return;
  91         si = mempool_alloc(mddev->serial_info_pool, GFP_NOIO);
  92         wait_event(serial->serial_io_wait,
  93                    check_and_add_serial(rdev, r1_bio, si, idx) == 0);
  94 }
  95
  96 static void remove_serial(struct md_rdev *rdev, sector_t lo, sector_t hi)
  97 {
  98         struct serial_info *si;
  99         unsigned long flags;
 100         int found = 0;
 101         struct mddev *mddev = rdev->mddev;
 102         int idx = sector_to_idx(lo);
 103         struct serial_in_rdev *serial = &rdev->serial[idx];
 104
 105         spin_lock_irqsave(&serial->serial_lock, flags);
 106         for (si = raid1_rb_iter_first(&serial->serial_rb, lo, hi);
 107              si; si = raid1_rb_iter_next(si, lo, hi)) {
 108                 if (si->start == lo && si->last == hi) {
 109                         raid1_rb_remove(si, &serial->serial_rb);
 110                         mempool_free(si, mddev->serial_info_pool);
 111                         found = 1;
 112                         break;
 113                 }
 114         }
 115         if (!found)
 116                 WARN(1, "The write IO is not recorded for serialization\n");
 117         spin_unlock_irqrestore(&serial->serial_lock, flags);
 118         wake_up(&serial->serial_io_wait);
 119 }
 120
 121 /*
 122  * for resync bio, r1bio pointer can be retrieved from the per-bio
 123  * 'struct resync_pages'.
 124  */
 125 static inline struct r1bio *get_resync_r1bio(struct bio *bio)
 126 {
 127         return get_resync_pages(bio)->raid_bio;
 128 }
 129
 130 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
 131 {
 132         struct pool_info *pi = data;
 133         int size = offsetof(struct r1bio, bios[pi->raid_disks]);
 134
 135         /* allocate a r1bio with room for raid_disks entries in the bios array */
 136         return kzalloc(size, gfp_flags);
 137 }
 138
 139 #define RESYNC_DEPTH 32
 140 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
 141 #define RESYNC_WINDOW (RESYNC_BLOCK_SIZE * RESYNC_DEPTH)
 142 #define RESYNC_WINDOW_SECTORS (RESYNC_WINDOW >> 9)
 143 #define CLUSTER_RESYNC_WINDOW (16 * RESYNC_WINDOW)
 144 #define CLUSTER_RESYNC_WINDOW_SECTORS (CLUSTER_RESYNC_WINDOW >> 9)
 145
 146 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
 147 {
 148         struct pool_info *pi = data;
 149         struct r1bio *r1_bio;
 150         struct bio *bio;
 151         int need_pages;
 152         int j;
 153         struct resync_pages *rps;
 154
 155         r1_bio = r1bio_pool_alloc(gfp_flags, pi);
 156         if (!r1_bio)
 157                 return NULL;
 158
 159         rps = kmalloc_array(pi->raid_disks, sizeof(struct resync_pages),
 160                             gfp_flags);
 161         if (!rps)
 162                 goto out_free_r1bio;
 163
 164         /*
 165          * Allocate bios : 1 for reading, n-1 for writing
 166          */
 167         for (j = pi->raid_disks ; j-- ; ) {
 168                 bio = bio_kmalloc(RESYNC_PAGES, gfp_flags);
 169                 if (!bio)
 170                         goto out_free_bio;
 171                 bio_init(bio, NULL, bio->bi_inline_vecs, RESYNC_PAGES, 0);
 172                 r1_bio->bios[j] = bio;
 173         }
 174         /*
 175          * Allocate RESYNC_PAGES data pages and attach them to
 176          * the first bio.
 177          * If this is a user-requested check/repair, allocate
 178          * RESYNC_PAGES for each bio.
 179          */
 180         if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
 181                 need_pages = pi->raid_disks;
 182         else
 183                 need_pages = 1;
 184         for (j = 0; j < pi->raid_disks; j++) {
 185                 struct resync_pages *rp = &rps[j];
 186
 187                 bio = r1_bio->bios[j];
 188
 189                 if (j < need_pages) {
 190                         if (resync_alloc_pages(rp, gfp_flags))
 191                                 goto out_free_pages;
 192                 } else {
 193                         memcpy(rp, &rps[0], sizeof(*rp));
 194                         resync_get_all_pages(rp);
 195                 }
 196
 197                 rp->raid_bio = r1_bio;
 198                 bio->bi_private = rp;
 199         }
 200
 201         r1_bio->master_bio = NULL;
 202
 203         return r1_bio;
 204
 205 out_free_pages:
 206         while (--j >= 0)
 207                 resync_free_pages(&rps[j]);
 208
 209 out_free_bio:
 210         while (++j < pi->raid_disks) {
 211                 bio_uninit(r1_bio->bios[j]);
 212                 kfree(r1_bio->bios[j]);
 213         }
 214         kfree(rps);
 215
 216 out_free_r1bio:
 217         rbio_pool_free(r1_bio, data);
 218         return NULL;
 219 }
 220
 221 static void r1buf_pool_free(void *__r1_bio, void *data)
 222 {
 223         struct pool_info *pi = data;
 224         int i;
 225         struct r1bio *r1bio = __r1_bio;
 226         struct resync_pages *rp = NULL;
 227
 228         for (i = pi->raid_disks; i--; ) {
 229                 rp = get_resync_pages(r1bio->bios[i]);
 230                 resync_free_pages(rp);
 231                 bio_uninit(r1bio->bios[i]);
 232                 kfree(r1bio->bios[i]);
 233         }
 234
 235         /* resync pages array stored in the 1st bio's .bi_private */
 236         kfree(rp);
 237
 238         rbio_pool_free(r1bio, data);
 239 }
 240
 241 static void put_all_bios(struct r1conf *conf, struct r1bio *r1_bio)
 242 {
 243         int i;
 244
 245         for (i = 0; i < conf->raid_disks * 2; i++) {
 246                 struct bio **bio = r1_bio->bios + i;
 247                 if (!BIO_SPECIAL(*bio))
 248                         bio_put(*bio);
 249                 *bio = NULL;
 250         }
 251 }
 252
 253 static void free_r1bio(struct r1bio *r1_bio)
 254 {
 255         struct r1conf *conf = r1_bio->mddev->private;
 256
 257         put_all_bios(conf, r1_bio);
 258         mempool_free(r1_bio, &conf->r1bio_pool);
 259 }
 260
 261 static void put_buf(struct r1bio *r1_bio)
 262 {
 263         struct r1conf *conf = r1_bio->mddev->private;
 264         sector_t sect = r1_bio->sector;
 265         int i;
 266
 267         for (i = 0; i < conf->raid_disks * 2; i++) {
 268                 struct bio *bio = r1_bio->bios[i];
 269                 if (bio->bi_end_io)
 270                         rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
 271         }
 272
 273         mempool_free(r1_bio, &conf->r1buf_pool);
 274
 275         lower_barrier(conf, sect);
 276 }
 277
 278 static void reschedule_retry(struct r1bio *r1_bio)
 279 {
 280         unsigned long flags;
 281         struct mddev *mddev = r1_bio->mddev;
 282         struct r1conf *conf = mddev->private;
 283         int idx;
 284
 285         idx = sector_to_idx(r1_bio->sector);
 286         spin_lock_irqsave(&conf->device_lock, flags);
 287         list_add(&r1_bio->retry_list, &conf->retry_list);
 288         atomic_inc(&conf->nr_queued[idx]);
 289         spin_unlock_irqrestore(&conf->device_lock, flags);
 290
 291         wake_up(&conf->wait_barrier);
 292         md_wakeup_thread(mddev->thread);
 293 }
 294
 295 /*
 296  * raid_end_bio_io() is called when we have finished servicing a mirrored
 297  * operation and are ready to return a success/failure code to the buffer
 298  * cache layer.
 299  */
 300 static void call_bio_endio(struct r1bio *r1_bio)
 301 {
 302         struct bio *bio = r1_bio->master_bio;
 303
 304         if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
 305                 bio->bi_status = BLK_STS_IOERR;
 306
 307         if (blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
 308                 bio_end_io_acct(bio, r1_bio->start_time);
 309         bio_endio(bio);
 310 }
 311
 312 static void raid_end_bio_io(struct r1bio *r1_bio)
 313 {
 314         struct bio *bio = r1_bio->master_bio;
 315         struct r1conf *conf = r1_bio->mddev->private;
 316
 317         /* if nobody has done the final endio yet, do it now */
 318         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 319                 pr_debug("raid1: sync end %s on sectors %llu-%llu\n",
 320                          (bio_data_dir(bio) == WRITE) ? "write" : "read",
 321                          (unsigned long long) bio->bi_iter.bi_sector,
 322                          (unsigned long long) bio_end_sector(bio) - 1);
 323
 324                 call_bio_endio(r1_bio);
 325         }
 326         /*
 327          * Wake up any possible resync thread that waits for the device
 328          * to go idle.  All I/Os, even write-behind writes, are done.
 329          */
 330         allow_barrier(conf, r1_bio->sector);
 331
 332         free_r1bio(r1_bio);
 333 }
 334
 335 /*
 336  * Update disk head position estimator based on IRQ completion info.
 337  */
 338 static inline void update_head_pos(int disk, struct r1bio *r1_bio)
 339 {
 340         struct r1conf *conf = r1_bio->mddev->private;
 341
 342         conf->mirrors[disk].head_position =
 343                 r1_bio->sector + (r1_bio->sectors);
 344 }
 345
 346 /*
 347  * Find the disk number which triggered given bio
 348  */
 349 static int find_bio_disk(struct r1bio *r1_bio, struct bio *bio)
 350 {
 351         int mirror;
 352         struct r1conf *conf = r1_bio->mddev->private;
 353         int raid_disks = conf->raid_disks;
 354
 355         for (mirror = 0; mirror < raid_disks * 2; mirror++)
 356                 if (r1_bio->bios[mirror] == bio)
 357                         break;
 358
 359         BUG_ON(mirror == raid_disks * 2);
 360         update_head_pos(mirror, r1_bio);
 361
 362         return mirror;
 363 }
 364
 365 static void raid1_end_read_request(struct bio *bio)
 366 {
 367         int uptodate = !bio->bi_status;
 368         struct r1bio *r1_bio = bio->bi_private;
 369         struct r1conf *conf = r1_bio->mddev->private;
 370         struct md_rdev *rdev = conf->mirrors[r1_bio->read_disk].rdev;
 371
 372         /*
 373          * this branch is our 'one mirror IO has finished' event handler:
 374          */
 375         update_head_pos(r1_bio->read_disk, r1_bio);
 376
 377         if (uptodate)
 378                 set_bit(R1BIO_Uptodate, &r1_bio->state);
 379         else if (test_bit(FailFast, &rdev->flags) &&
 380                  test_bit(R1BIO_FailFast, &r1_bio->state))
 381                 /* This was a fail-fast read so we definitely
 382                  * want to retry */
 383                 ;
 384         else {
 385                 /* If all other devices have failed, we want to return
 386                  * the error upwards rather than fail the last device.
 387                  * Here we redefine "uptodate" to mean "Don't want to retry"
 388                  */
 389                 unsigned long flags;
 390                 spin_lock_irqsave(&conf->device_lock, flags);
 391                 if (r1_bio->mddev->degraded == conf->raid_disks ||
 392                     (r1_bio->mddev->degraded == conf->raid_disks-1 &&
 393                      test_bit(In_sync, &rdev->flags)))
 394                         uptodate = 1;
 395                 spin_unlock_irqrestore(&conf->device_lock, flags);
 396         }
 397
 398         if (uptodate) {
 399                 raid_end_bio_io(r1_bio);
 400                 rdev_dec_pending(rdev, conf->mddev);
 401         } else {
 402                 /*
 403                  * oops, read error:
 404                  */
 405                 pr_err_ratelimited("md/raid1:%s: %pg: rescheduling sector %llu\n",
 406                                    mdname(conf->mddev),
 407                                    rdev->bdev,
 408                                    (unsigned long long)r1_bio->sector);
 409                 set_bit(R1BIO_ReadError, &r1_bio->state);
 410                 reschedule_retry(r1_bio);
 411                 /* don't drop the reference on read_disk yet */
 412         }
 413 }
 414
 415 static void close_write(struct r1bio *r1_bio)
 416 {
 417         /* it really is the end of this request */
 418         if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
 419                 bio_free_pages(r1_bio->behind_master_bio);
 420                 bio_put(r1_bio->behind_master_bio);
 421                 r1_bio->behind_master_bio = NULL;
 422         }
 423         /* clear the bitmap if all writes complete successfully */
 424         md_bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
 425                            r1_bio->sectors,
 426                            !test_bit(R1BIO_Degraded, &r1_bio->state),
 427                            test_bit(R1BIO_BehindIO, &r1_bio->state));
 428         md_write_end(r1_bio->mddev);
 429 }
 430
 431 static void r1_bio_write_done(struct r1bio *r1_bio)
 432 {
 433         if (!atomic_dec_and_test(&r1_bio->remaining))
 434                 return;
 435
 436         if (test_bit(R1BIO_WriteError, &r1_bio->state))
 437                 reschedule_retry(r1_bio);
 438         else {
 439                 close_write(r1_bio);
 440                 if (test_bit(R1BIO_MadeGood, &r1_bio->state))
 441                         reschedule_retry(r1_bio);
 442                 else
 443                         raid_end_bio_io(r1_bio);
 444         }
 445 }
 446
 447 static void raid1_end_write_request(struct bio *bio)
 448 {
 449         struct r1bio *r1_bio = bio->bi_private;
 450         int behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
 451         struct r1conf *conf = r1_bio->mddev->private;
 452         struct bio *to_put = NULL;
 453         int mirror = find_bio_disk(r1_bio, bio);
 454         struct md_rdev *rdev = conf->mirrors[mirror].rdev;
 455         bool discard_error;
 456         sector_t lo = r1_bio->sector;
 457         sector_t hi = r1_bio->sector + r1_bio->sectors;
 458
 459         discard_error = bio->bi_status && bio_op(bio) == REQ_OP_DISCARD;
 460
 461         /*
 462          * 'one mirror IO has finished' event handler:
 463          */
 464         if (bio->bi_status && !discard_error) {
 465                 set_bit(WriteErrorSeen, &rdev->flags);
 466                 if (!test_and_set_bit(WantReplacement, &rdev->flags))
 467                         set_bit(MD_RECOVERY_NEEDED, &
 468                                 conf->mddev->recovery);
 469
 470                 if (test_bit(FailFast, &rdev->flags) &&
 471                     (bio->bi_opf & MD_FAILFAST) &&
 472                     /* We never try FailFast to WriteMostly devices */
 473                     !test_bit(WriteMostly, &rdev->flags)) {
 474                         md_error(r1_bio->mddev, rdev);
 475                 }
 476
 477                 /*
 478                  * When the device is faulty, it is not necessary to
 479                  * handle write error.
 480                  */
 481                 if (!test_bit(Faulty, &rdev->flags))
 482                         set_bit(R1BIO_WriteError, &r1_bio->state);
 483                 else {
 484                         /* Fail the request */
 485                         set_bit(R1BIO_Degraded, &r1_bio->state);
 486                         /* Finished with this branch */
 487                         r1_bio->bios[mirror] = NULL;
 488                         to_put = bio;
 489                 }
 490         } else {
 491                 /*
 492                  * Set R1BIO_Uptodate in our master bio, so that we
 493                  * will return a good error code for to the higher
 494                  * levels even if IO on some other mirrored buffer
 495                  * fails.
 496                  *
 497                  * The 'master' represents the composite IO operation
 498                  * to user-side. So if something waits for IO, then it
 499                  * will wait for the 'master' bio.
 500                  */
 501                 sector_t first_bad;
 502                 int bad_sectors;
 503
 504                 r1_bio->bios[mirror] = NULL;
 505                 to_put = bio;
 506                 /*
 507                  * Do not set R1BIO_Uptodate if the current device is
 508                  * rebuilding or Faulty. This is because we cannot use
 509                  * such device for properly reading the data back (we could
 510                  * potentially use it, if the current write would have felt
 511                  * before rdev->recovery_offset, but for simplicity we don't
 512                  * check this here.
 513                  */
 514                 if (test_bit(In_sync, &rdev->flags) &&
 515                     !test_bit(Faulty, &rdev->flags))
 516                         set_bit(R1BIO_Uptodate, &r1_bio->state);
 517
 518                 /* Maybe we can clear some bad blocks. */
 519                 if (is_badblock(rdev, r1_bio->sector, r1_bio->sectors,
 520                                 &first_bad, &bad_sectors) && !discard_error) {
 521                         r1_bio->bios[mirror] = IO_MADE_GOOD;
 522                         set_bit(R1BIO_MadeGood, &r1_bio->state);
 523                 }
 524         }
 525
 526         if (behind) {
 527                 if (test_bit(CollisionCheck, &rdev->flags))
 528                         remove_serial(rdev, lo, hi);
 529                 if (test_bit(WriteMostly, &rdev->flags))
 530                         atomic_dec(&r1_bio->behind_remaining);
 531
 532                 /*
 533                  * In behind mode, we ACK the master bio once the I/O
 534                  * has safely reached all non-writemostly
 535                  * disks. Setting the Returned bit ensures that this
 536                  * gets done only once -- we don't ever want to return
 537                  * -EIO here, instead we'll wait
 538                  */
 539                 if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
 540                     test_bit(R1BIO_Uptodate, &r1_bio->state)) {
 541                         /* Maybe we can return now */
 542                         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 543                                 struct bio *mbio = r1_bio->master_bio;
 544                                 pr_debug("raid1: behind end write sectors"
 545                                          " %llu-%llu\n",
 546                                          (unsigned long long) mbio->bi_iter.bi_sector,
 547                                          (unsigned long long) bio_end_sector(mbio) - 1);
 548                                 call_bio_endio(r1_bio);
 549                         }
 550                 }
 551         } else if (rdev->mddev->serialize_policy)
 552                 remove_serial(rdev, lo, hi);
 553         if (r1_bio->bios[mirror] == NULL)
 554                 rdev_dec_pending(rdev, conf->mddev);
 555
 556         /*
 557          * Let's see if all mirrored write operations have finished
 558          * already.
 559          */
 560         r1_bio_write_done(r1_bio);
 561
 562         if (to_put)
 563                 bio_put(to_put);
 564 }
 565
 566 static sector_t align_to_barrier_unit_end(sector_t start_sector,
 567                                           sector_t sectors)
 568 {
 569         sector_t len;
 570
 571         WARN_ON(sectors == 0);
 572         /*
 573          * len is the number of sectors from start_sector to end of the
 574          * barrier unit which start_sector belongs to.
 575          */
 576         len = round_up(start_sector + 1, BARRIER_UNIT_SECTOR_SIZE) -
 577               start_sector;
 578
 579         if (len > sectors)
 580                 len = sectors;
 581
 582         return len;
 583 }
 584
 585 /*
 586  * This routine returns the disk from which the requested read should
 587  * be done. There is a per-array 'next expected sequential IO' sector
 588  * number - if this matches on the next IO then we use the last disk.
 589  * There is also a per-disk 'last know head position' sector that is
 590  * maintained from IRQ contexts, both the normal and the resync IO
 591  * completion handlers update this position correctly. If there is no
 592  * perfect sequential match then we pick the disk whose head is closest.
 593  *
 594  * If there are 2 mirrors in the same 2 devices, performance degrades
 595  * because position is mirror, not device based.
 596  *
 597  * The rdev for the device selected will have nr_pending incremented.
 598  */
 599 static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sectors)
 600 {
 601         const sector_t this_sector = r1_bio->sector;
 602         int sectors;
 603         int best_good_sectors;
 604         int best_disk, best_dist_disk, best_pending_disk;
 605         int has_nonrot_disk;
 606         int disk;
 607         sector_t best_dist;
 608         unsigned int min_pending;
 609         struct md_rdev *rdev;
 610         int choose_first;
 611         int choose_next_idle;
 612
 613         rcu_read_lock();
 614         /*
 615          * Check if we can balance. We can balance on the whole
 616          * device if no resync is going on, or below the resync window.
 617          * We take the first readable disk when above the resync window.
 618          */
 619  retry:
 620         sectors = r1_bio->sectors;
 621         best_disk = -1;
 622         best_dist_disk = -1;
 623         best_dist = MaxSector;
 624         best_pending_disk = -1;
 625         min_pending = UINT_MAX;
 626         best_good_sectors = 0;
 627         has_nonrot_disk = 0;
 628         choose_next_idle = 0;
 629         clear_bit(R1BIO_FailFast, &r1_bio->state);
 630
 631         if ((conf->mddev->recovery_cp < this_sector + sectors) ||
 632             (mddev_is_clustered(conf->mddev) &&
 633             md_cluster_ops->area_resyncing(conf->mddev, READ, this_sector,
 634                     this_sector + sectors)))
 635                 choose_first = 1;
 636         else
 637                 choose_first = 0;
 638
 639         for (disk = 0 ; disk < conf->raid_disks * 2 ; disk++) {
 640                 sector_t dist;
 641                 sector_t first_bad;
 642                 int bad_sectors;
 643                 unsigned int pending;
 644                 bool nonrot;
 645
 646                 rdev = rcu_dereference(conf->mirrors[disk].rdev);
 647                 if (r1_bio->bios[disk] == IO_BLOCKED
 648                     || rdev == NULL
 649                     || test_bit(Faulty, &rdev->flags))
 650                         continue;
 651                 if (!test_bit(In_sync, &rdev->flags) &&
 652                     rdev->recovery_offset < this_sector + sectors)
 653                         continue;
 654                 if (test_bit(WriteMostly, &rdev->flags)) {
 655                         /* Don't balance among write-mostly, just
 656                          * use the first as a last resort */
 657                         if (best_dist_disk < 0) {
 658                                 if (is_badblock(rdev, this_sector, sectors,
 659                                                 &first_bad, &bad_sectors)) {
 660                                         if (first_bad <= this_sector)
 661                                                 /* Cannot use this */
 662                                                 continue;
 663                                         best_good_sectors = first_bad - this_sector;
 664                                 } else
 665                                         best_good_sectors = sectors;
 666                                 best_dist_disk = disk;
 667                                 best_pending_disk = disk;
 668                         }
 669                         continue;
 670                 }
 671                 /* This is a reasonable device to use.  It might
 672                  * even be best.
 673                  */
 674                 if (is_badblock(rdev, this_sector, sectors,
 675                                 &first_bad, &bad_sectors)) {
 676                         if (best_dist < MaxSector)
 677                                 /* already have a better device */
 678                                 continue;
 679                         if (first_bad <= this_sector) {
 680                                 /* cannot read here. If this is the 'primary'
 681                                  * device, then we must not read beyond
 682                                  * bad_sectors from another device..
 683                                  */
 684                                 bad_sectors -= (this_sector - first_bad);
 685                                 if (choose_first && sectors > bad_sectors)
 686                                         sectors = bad_sectors;
 687                                 if (best_good_sectors > sectors)
 688                                         best_good_sectors = sectors;
 689
 690                         } else {
 691                                 sector_t good_sectors = first_bad - this_sector;
 692                                 if (good_sectors > best_good_sectors) {
 693                                         best_good_sectors = good_sectors;
 694                                         best_disk = disk;
 695                                 }
 696                                 if (choose_first)
 697                                         break;
 698                         }
 699                         continue;
 700                 } else {
 701                         if ((sectors > best_good_sectors) && (best_disk >= 0))
 702                                 best_disk = -1;
 703                         best_good_sectors = sectors;
 704                 }
 705
 706                 if (best_disk >= 0)
 707                         /* At least two disks to choose from so failfast is OK */
 708                         set_bit(R1BIO_FailFast, &r1_bio->state);
 709
 710                 nonrot = bdev_nonrot(rdev->bdev);
 711                 has_nonrot_disk |= nonrot;
 712                 pending = atomic_read(&rdev->nr_pending);
 713                 dist = abs(this_sector - conf->mirrors[disk].head_position);
 714                 if (choose_first) {
 715                         best_disk = disk;
 716                         break;
 717                 }
 718                 /* Don't change to another disk for sequential reads */
 719                 if (conf->mirrors[disk].next_seq_sect == this_sector
 720                     || dist == 0) {
 721                         int opt_iosize = bdev_io_opt(rdev->bdev) >> 9;
 722                         struct raid1_info *mirror = &conf->mirrors[disk];
 723
 724                         best_disk = disk;
 725                         /*
 726                          * If buffered sequential IO size exceeds optimal
 727                          * iosize, check if there is idle disk. If yes, choose
 728                          * the idle disk. read_balance could already choose an
 729                          * idle disk before noticing it's a sequential IO in
 730                          * this disk. This doesn't matter because this disk
 731                          * will idle, next time it will be utilized after the
 732                          * first disk has IO size exceeds optimal iosize. In
 733                          * this way, iosize of the first disk will be optimal
 734                          * iosize at least. iosize of the second disk might be
 735                          * small, but not a big deal since when the second disk
 736                          * starts IO, the first disk is likely still busy.
 737                          */
 738                         if (nonrot && opt_iosize > 0 &&
 739                             mirror->seq_start != MaxSector &&
 740                             mirror->next_seq_sect > opt_iosize &&
 741                             mirror->next_seq_sect - opt_iosize >=
 742                             mirror->seq_start) {
 743                                 choose_next_idle = 1;
 744                                 continue;
 745                         }
 746                         break;
 747                 }
 748
 749                 if (choose_next_idle)
 750                         continue;
 751
 752                 if (min_pending > pending) {
 753                         min_pending = pending;
 754                         best_pending_disk = disk;
 755                 }
 756
 757                 if (dist < best_dist) {
 758                         best_dist = dist;
 759                         best_dist_disk = disk;
 760                 }
 761         }
 762
 763         /*
 764          * If all disks are rotational, choose the closest disk. If any disk is
 765          * non-rotational, choose the disk with less pending request even the
 766          * disk is rotational, which might/might not be optimal for raids with
 767          * mixed ratation/non-rotational disks depending on workload.
 768          */
 769         if (best_disk == -1) {
 770                 if (has_nonrot_disk || min_pending == 0)
 771                         best_disk = best_pending_disk;
 772                 else
 773                         best_disk = best_dist_disk;
 774         }
 775
 776         if (best_disk >= 0) {
 777                 rdev = rcu_dereference(conf->mirrors[best_disk].rdev);
 778                 if (!rdev)
 779                         goto retry;
 780                 atomic_inc(&rdev->nr_pending);
 781                 sectors = best_good_sectors;
 782
 783                 if (conf->mirrors[best_disk].next_seq_sect != this_sector)
 784                         conf->mirrors[best_disk].seq_start = this_sector;
 785
 786                 conf->mirrors[best_disk].next_seq_sect = this_sector + sectors;
 787         }
 788         rcu_read_unlock();
 789         *max_sectors = sectors;
 790
 791         return best_disk;
 792 }
 793
 794 static void flush_bio_list(struct r1conf *conf, struct bio *bio)
 795 {
 796         /* flush any pending bitmap writes to disk before proceeding w/ I/O */
 797         md_bitmap_unplug(conf->mddev->bitmap);
 798         wake_up(&conf->wait_barrier);
 799
 800         while (bio) { /* submit pending writes */
 801                 struct bio *next = bio->bi_next;
 802                 struct md_rdev *rdev = (void *)bio->bi_bdev;
 803                 bio->bi_next = NULL;
 804                 bio_set_dev(bio, rdev->bdev);
 805                 if (test_bit(Faulty, &rdev->flags)) {
 806                         bio_io_error(bio);
 807                 } else if (unlikely((bio_op(bio) == REQ_OP_DISCARD) &&
 808                                     !bdev_max_discard_sectors(bio->bi_bdev)))
 809                         /* Just ignore it */
 810                         bio_endio(bio);
 811                 else
 812                         submit_bio_noacct(bio);
 813                 bio = next;
 814                 cond_resched();
 815         }
 816 }
 817
 818 static void flush_pending_writes(struct r1conf *conf)
 819 {
 820         /* Any writes that have been queued but are awaiting
 821          * bitmap updates get flushed here.
 822          */
 823         spin_lock_irq(&conf->device_lock);
 824
 825         if (conf->pending_bio_list.head) {
 826                 struct blk_plug plug;
 827                 struct bio *bio;
 828
 829                 bio = bio_list_get(&conf->pending_bio_list);
 830                 spin_unlock_irq(&conf->device_lock);
 831
 832                 /*
 833                  * As this is called in a wait_event() loop (see freeze_array),
 834                  * current->state might be TASK_UNINTERRUPTIBLE which will
 835                  * cause a warning when we prepare to wait again.  As it is
 836                  * rare that this path is taken, it is perfectly safe to force
 837                  * us to go around the wait_event() loop again, so the warning
 838                  * is a false-positive.  Silence the warning by resetting
 839                  * thread state
 840                  */
 841                 __set_current_state(TASK_RUNNING);
 842                 blk_start_plug(&plug);
 843                 flush_bio_list(conf, bio);
 844                 blk_finish_plug(&plug);
 845         } else
 846                 spin_unlock_irq(&conf->device_lock);
 847 }
 848
 849 /* Barriers....
 850  * Sometimes we need to suspend IO while we do something else,
 851  * either some resync/recovery, or reconfigure the array.
 852  * To do this we raise a 'barrier'.
 853  * The 'barrier' is a counter that can be raised multiple times
 854  * to count how many activities are happening which preclude
 855  * normal IO.
 856  * We can only raise the barrier if there is no pending IO.
 857  * i.e. if nr_pending == 0.
 858  * We choose only to raise the barrier if no-one is waiting for the
 859  * barrier to go down.  This means that as soon as an IO request
 860  * is ready, no other operations which require a barrier will start
 861  * until the IO request has had a chance.
 862  *
 863  * So: regular IO calls 'wait_barrier'.  When that returns there
 864  *    is no backgroup IO happening,  It must arrange to call
 865  *    allow_barrier when it has finished its IO.
 866  * backgroup IO calls must call raise_barrier.  Once that returns
 867  *    there is no normal IO happeing.  It must arrange to call
 868  *    lower_barrier when the particular background IO completes.
 869  *
 870  * If resync/recovery is interrupted, returns -EINTR;
 871  * Otherwise, returns 0.
 872  */
 873 static int raise_barrier(struct r1conf *conf, sector_t sector_nr)
 874 {
 875         int idx = sector_to_idx(sector_nr);
 876
 877         spin_lock_irq(&conf->resync_lock);
 878
 879         /* Wait until no block IO is waiting */
 880         wait_event_lock_irq(conf->wait_barrier,
 881                             !atomic_read(&conf->nr_waiting[idx]),
 882                             conf->resync_lock);
 883
 884         /* block any new IO from starting */
 885         atomic_inc(&conf->barrier[idx]);
 886         /*
 887          * In raise_barrier() we firstly increase conf->barrier[idx] then
 888          * check conf->nr_pending[idx]. In _wait_barrier() we firstly
 889          * increase conf->nr_pending[idx] then check conf->barrier[idx].
 890          * A memory barrier here to make sure conf->nr_pending[idx] won't
 891          * be fetched before conf->barrier[idx] is increased. Otherwise
 892          * there will be a race between raise_barrier() and _wait_barrier().
 893          */
 894         smp_mb__after_atomic();
 895
 896         /* For these conditions we must wait:
 897          * A: while the array is in frozen state
 898          * B: while conf->nr_pending[idx] is not 0, meaning regular I/O
 899          *    existing in corresponding I/O barrier bucket.
 900          * C: while conf->barrier[idx] >= RESYNC_DEPTH, meaning reaches
 901          *    max resync count which allowed on current I/O barrier bucket.
 902          */
 903         wait_event_lock_irq(conf->wait_barrier,
 904                             (!conf->array_frozen &&
 905                              !atomic_read(&conf->nr_pending[idx]) &&
 906                              atomic_read(&conf->barrier[idx]) < RESYNC_DEPTH) ||
 907                                 test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery),
 908                             conf->resync_lock);
 909
 910         if (test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
 911                 atomic_dec(&conf->barrier[idx]);
 912                 spin_unlock_irq(&conf->resync_lock);
 913                 wake_up(&conf->wait_barrier);
 914                 return -EINTR;
 915         }
 916
 917         atomic_inc(&conf->nr_sync_pending);
 918         spin_unlock_irq(&conf->resync_lock);
 919
 920         return 0;
 921 }
 922
 923 static void lower_barrier(struct r1conf *conf, sector_t sector_nr)
 924 {
 925         int idx = sector_to_idx(sector_nr);
 926
 927         BUG_ON(atomic_read(&conf->barrier[idx]) <= 0);
 928
 929         atomic_dec(&conf->barrier[idx]);
 930         atomic_dec(&conf->nr_sync_pending);
 931         wake_up(&conf->wait_barrier);
 932 }
 933
 934 static bool _wait_barrier(struct r1conf *conf, int idx, bool nowait)
 935 {
 936         bool ret = true;
 937
 938         /*
 939          * We need to increase conf->nr_pending[idx] very early here,
 940          * then raise_barrier() can be blocked when it waits for
 941          * conf->nr_pending[idx] to be 0. Then we can avoid holding
 942          * conf->resync_lock when there is no barrier raised in same
 943          * barrier unit bucket. Also if the array is frozen, I/O
 944          * should be blocked until array is unfrozen.
 945          */
 946         atomic_inc(&conf->nr_pending[idx]);
 947         /*
 948          * In _wait_barrier() we firstly increase conf->nr_pending[idx], then
 949          * check conf->barrier[idx]. In raise_barrier() we firstly increase
 950          * conf->barrier[idx], then check conf->nr_pending[idx]. A memory
 951          * barrier is necessary here to make sure conf->barrier[idx] won't be
 952          * fetched before conf->nr_pending[idx] is increased. Otherwise there
 953          * will be a race between _wait_barrier() and raise_barrier().
 954          */
 955         smp_mb__after_atomic();
 956
 957         /*
 958          * Don't worry about checking two atomic_t variables at same time
 959          * here. If during we check conf->barrier[idx], the array is
 960          * frozen (conf->array_frozen is 1), and chonf->barrier[idx] is
 961          * 0, it is safe to return and make the I/O continue. Because the
 962          * array is frozen, all I/O returned here will eventually complete
 963          * or be queued, no race will happen. See code comment in
 964          * frozen_array().
 965          */
 966         if (!READ_ONCE(conf->array_frozen) &&
 967             !atomic_read(&conf->barrier[idx]))
 968                 return ret;
 969
 970         /*
 971          * After holding conf->resync_lock, conf->nr_pending[idx]
 972          * should be decreased before waiting for barrier to drop.
 973          * Otherwise, we may encounter a race condition because
 974          * raise_barrer() might be waiting for conf->nr_pending[idx]
 975          * to be 0 at same time.
 976          */
 977         spin_lock_irq(&conf->resync_lock);
 978         atomic_inc(&conf->nr_waiting[idx]);
 979         atomic_dec(&conf->nr_pending[idx]);
 980         /*
 981          * In case freeze_array() is waiting for
 982          * get_unqueued_pending() == extra
 983          */
 984         wake_up(&conf->wait_barrier);
 985         /* Wait for the barrier in same barrier unit bucket to drop. */
 986
 987         /* Return false when nowait flag is set */
 988         if (nowait) {
 989                 ret = false;
 990         } else {
 991                 wait_event_lock_irq(conf->wait_barrier,
 992                                 !conf->array_frozen &&
 993                                 !atomic_read(&conf->barrier[idx]),
 994                                 conf->resync_lock);
 995                 atomic_inc(&conf->nr_pending[idx]);
 996         }
 997
 998         atomic_dec(&conf->nr_waiting[idx]);
 999         spin_unlock_irq(&conf->resync_lock);
1000         return ret;
1001 }
1002
1003 static bool wait_read_barrier(struct r1conf *conf, sector_t sector_nr, bool nowait)
1004 {
1005         int idx = sector_to_idx(sector_nr);
1006         bool ret = true;
1007
1008         /*
1009          * Very similar to _wait_barrier(). The difference is, for read
1010          * I/O we don't need wait for sync I/O, but if the whole array
1011          * is frozen, the read I/O still has to wait until the array is
1012          * unfrozen. Since there is no ordering requirement with
1013          * conf->barrier[idx] here, memory barrier is unnecessary as well.
1014          */
1015         atomic_inc(&conf->nr_pending[idx]);
1016
1017         if (!READ_ONCE(conf->array_frozen))
1018                 return ret;
1019
1020         spin_lock_irq(&conf->resync_lock);
1021         atomic_inc(&conf->nr_waiting[idx]);
1022         atomic_dec(&conf->nr_pending[idx]);
1023         /*
1024          * In case freeze_array() is waiting for
1025          * get_unqueued_pending() == extra
1026          */
1027         wake_up(&conf->wait_barrier);
1028         /* Wait for array to be unfrozen */
1029
1030         /* Return false when nowait flag is set */
1031         if (nowait) {
1032                 /* Return false when nowait flag is set */
1033                 ret = false;
1034         } else {
1035                 wait_event_lock_irq(conf->wait_barrier,
1036                                 !conf->array_frozen,
1037                                 conf->resync_lock);
1038                 atomic_inc(&conf->nr_pending[idx]);
1039         }
1040
1041         atomic_dec(&conf->nr_waiting[idx]);
1042         spin_unlock_irq(&conf->resync_lock);
1043         return ret;
1044 }
1045
1046 static bool wait_barrier(struct r1conf *conf, sector_t sector_nr, bool nowait)
1047 {
1048         int idx = sector_to_idx(sector_nr);
1049
1050         return _wait_barrier(conf, idx, nowait);
1051 }
1052
1053 static void _allow_barrier(struct r1conf *conf, int idx)
1054 {
1055         atomic_dec(&conf->nr_pending[idx]);
1056         wake_up(&conf->wait_barrier);
1057 }
1058
1059 static void allow_barrier(struct r1conf *conf, sector_t sector_nr)
1060 {
1061         int idx = sector_to_idx(sector_nr);
1062
1063         _allow_barrier(conf, idx);
1064 }
1065
1066 /* conf->resync_lock should be held */
1067 static int get_unqueued_pending(struct r1conf *conf)
1068 {
1069         int idx, ret;
1070
1071         ret = atomic_read(&conf->nr_sync_pending);
1072         for (idx = 0; idx < BARRIER_BUCKETS_NR; idx++)
1073                 ret += atomic_read(&conf->nr_pending[idx]) -
1074                         atomic_read(&conf->nr_queued[idx]);
1075
1076         return ret;
1077 }
1078
1079 static void freeze_array(struct r1conf *conf, int extra)
1080 {
1081         /* Stop sync I/O and normal I/O and wait for everything to
1082          * go quiet.
1083          * This is called in two situations:
1084          * 1) management command handlers (reshape, remove disk, quiesce).
1085          * 2) one normal I/O request failed.
1086
1087          * After array_frozen is set to 1, new sync IO will be blocked at
1088          * raise_barrier(), and new normal I/O will blocked at _wait_barrier()
1089          * or wait_read_barrier(). The flying I/Os will either complete or be
1090          * queued. When everything goes quite, there are only queued I/Os left.
1091
1092          * Every flying I/O contributes to a conf->nr_pending[idx], idx is the
1093          * barrier bucket index which this I/O request hits. When all sync and
1094          * normal I/O are queued, sum of all conf->nr_pending[] will match sum
1095          * of all conf->nr_queued[]. But normal I/O failure is an exception,
1096          * in handle_read_error(), we may call freeze_array() before trying to
1097          * fix the read error. In this case, the error read I/O is not queued,
1098          * so get_unqueued_pending() == 1.
1099          *
1100          * Therefore before this function returns, we need to wait until
1101          * get_unqueued_pendings(conf) gets equal to extra. For
1102          * normal I/O context, extra is 1, in rested situations extra is 0.
1103          */
1104         spin_lock_irq(&conf->resync_lock);
1105         conf->array_frozen = 1;
1106         raid1_log(conf->mddev, "wait freeze");
1107         wait_event_lock_irq_cmd(
1108                 conf->wait_barrier,
1109                 get_unqueued_pending(conf) == extra,
1110                 conf->resync_lock,
1111                 flush_pending_writes(conf));
1112         spin_unlock_irq(&conf->resync_lock);
1113 }
1114 static void unfreeze_array(struct r1conf *conf)
1115 {
1116         /* reverse the effect of the freeze */
1117         spin_lock_irq(&conf->resync_lock);
1118         conf->array_frozen = 0;
1119         spin_unlock_irq(&conf->resync_lock);
1120         wake_up(&conf->wait_barrier);
1121 }
1122
1123 static void alloc_behind_master_bio(struct r1bio *r1_bio,
1124                                            struct bio *bio)
1125 {
1126         int size = bio->bi_iter.bi_size;
1127         unsigned vcnt = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
1128         int i = 0;
1129         struct bio *behind_bio = NULL;
1130
1131         behind_bio = bio_alloc_bioset(NULL, vcnt, 0, GFP_NOIO,
1132                                       &r1_bio->mddev->bio_set);
1133         if (!behind_bio)
1134                 return;
1135
1136         /* discard op, we don't support writezero/writesame yet */
1137         if (!bio_has_data(bio)) {
1138                 behind_bio->bi_iter.bi_size = size;
1139                 goto skip_copy;
1140         }
1141
1142         while (i < vcnt && size) {
1143                 struct page *page;
1144                 int len = min_t(int, PAGE_SIZE, size);
1145
1146                 page = alloc_page(GFP_NOIO);
1147                 if (unlikely(!page))
1148                         goto free_pages;
1149
1150                 bio_add_page(behind_bio, page, len, 0);
1151
1152                 size -= len;
1153                 i++;
1154         }
1155
1156         bio_copy_data(behind_bio, bio);
1157 skip_copy:
1158         r1_bio->behind_master_bio = behind_bio;
1159         set_bit(R1BIO_BehindIO, &r1_bio->state);
1160
1161         return;
1162
1163 free_pages:
1164         pr_debug("%dB behind alloc failed, doing sync I/O\n",
1165                  bio->bi_iter.bi_size);
1166         bio_free_pages(behind_bio);
1167         bio_put(behind_bio);
1168 }
1169
1170 static void raid1_unplug(struct blk_plug_cb *cb, bool from_schedule)
1171 {
1172         struct raid1_plug_cb *plug = container_of(cb, struct raid1_plug_cb,
1173                                                   cb);
1174         struct mddev *mddev = plug->cb.data;
1175         struct r1conf *conf = mddev->private;
1176         struct bio *bio;
1177
1178         if (from_schedule || current->bio_list) {
1179                 spin_lock_irq(&conf->device_lock);
1180                 bio_list_merge(&conf->pending_bio_list, &plug->pending);
1181                 spin_unlock_irq(&conf->device_lock);
1182                 wake_up(&conf->wait_barrier);
1183                 md_wakeup_thread(mddev->thread);
1184                 kfree(plug);
1185                 return;
1186         }
1187
1188         /* we aren't scheduling, so we can do the write-out directly. */
1189         bio = bio_list_get(&plug->pending);
1190         flush_bio_list(conf, bio);
1191         kfree(plug);
1192 }
1193
1194 static void init_r1bio(struct r1bio *r1_bio, struct mddev *mddev, struct bio *bio)
1195 {
1196         r1_bio->master_bio = bio;
1197         r1_bio->sectors = bio_sectors(bio);
1198         r1_bio->state = 0;
1199         r1_bio->mddev = mddev;
1200         r1_bio->sector = bio->bi_iter.bi_sector;
1201 }
1202
1203 static inline struct r1bio *
1204 alloc_r1bio(struct mddev *mddev, struct bio *bio)
1205 {
1206         struct r1conf *conf = mddev->private;
1207         struct r1bio *r1_bio;
1208
1209         r1_bio = mempool_alloc(&conf->r1bio_pool, GFP_NOIO);
1210         /* Ensure no bio records IO_BLOCKED */
1211         memset(r1_bio->bios, 0, conf->raid_disks * sizeof(r1_bio->bios[0]));
1212         init_r1bio(r1_bio, mddev, bio);
1213         return r1_bio;
1214 }
1215
1216 static void raid1_read_request(struct mddev *mddev, struct bio *bio,
1217                                int max_read_sectors, struct r1bio *r1_bio)
1218 {
1219         struct r1conf *conf = mddev->private;
1220         struct raid1_info *mirror;
1221         struct bio *read_bio;
1222         struct bitmap *bitmap = mddev->bitmap;
1223         const int op = bio_op(bio);
1224         const unsigned long do_sync = (bio->bi_opf & REQ_SYNC);
1225         int max_sectors;
1226         int rdisk;
1227         bool r1bio_existed = !!r1_bio;
1228         char b[BDEVNAME_SIZE];
1229
1230         /*
1231          * If r1_bio is set, we are blocking the raid1d thread
1232          * so there is a tiny risk of deadlock.  So ask for
1233          * emergency memory if needed.
1234          */
1235         gfp_t gfp = r1_bio ? (GFP_NOIO | __GFP_HIGH) : GFP_NOIO;
1236
1237         if (r1bio_existed) {
1238                 /* Need to get the block device name carefully */
1239                 struct md_rdev *rdev;
1240                 rcu_read_lock();
1241                 rdev = rcu_dereference(conf->mirrors[r1_bio->read_disk].rdev);
1242                 if (rdev)
1243                         bdevname(rdev->bdev, b);
1244                 else
1245                         strcpy(b, "???");
1246                 rcu_read_unlock();
1247         }
1248
1249         /*
1250          * Still need barrier for READ in case that whole
1251          * array is frozen.
1252          */
1253         if (!wait_read_barrier(conf, bio->bi_iter.bi_sector,
1254                                 bio->bi_opf & REQ_NOWAIT)) {
1255                 bio_wouldblock_error(bio);
1256                 return;
1257         }
1258
1259         if (!r1_bio)
1260                 r1_bio = alloc_r1bio(mddev, bio);
1261         else
1262                 init_r1bio(r1_bio, mddev, bio);
1263         r1_bio->sectors = max_read_sectors;
1264
1265         /*
1266          * make_request() can abort the operation when read-ahead is being
1267          * used and no empty request is available.
1268          */
1269         rdisk = read_balance(conf, r1_bio, &max_sectors);
1270
1271         if (rdisk < 0) {
1272                 /* couldn't find anywhere to read from */
1273                 if (r1bio_existed) {
1274                         pr_crit_ratelimited("md/raid1:%s: %s: unrecoverable I/O read error for block %llu\n",
1275                                             mdname(mddev),
1276                                             b,
1277                                             (unsigned long long)r1_bio->sector);
1278                 }
1279                 raid_end_bio_io(r1_bio);
1280                 return;
1281         }
1282         mirror = conf->mirrors + rdisk;
1283
1284         if (r1bio_existed)
1285                 pr_info_ratelimited("md/raid1:%s: redirecting sector %llu to other mirror: %pg\n",
1286                                     mdname(mddev),
1287                                     (unsigned long long)r1_bio->sector,
1288                                     mirror->rdev->bdev);
1289
1290         if (test_bit(WriteMostly, &mirror->rdev->flags) &&
1291             bitmap) {
1292                 /*
1293                  * Reading from a write-mostly device must take care not to
1294                  * over-take any writes that are 'behind'
1295                  */
1296                 raid1_log(mddev, "wait behind writes");
1297                 wait_event(bitmap->behind_wait,
1298                            atomic_read(&bitmap->behind_writes) == 0);
1299         }
1300
1301         if (max_sectors < bio_sectors(bio)) {
1302                 struct bio *split = bio_split(bio, max_sectors,
1303                                               gfp, &conf->bio_split);
1304                 bio_chain(split, bio);
1305                 submit_bio_noacct(bio);
1306                 bio = split;
1307                 r1_bio->master_bio = bio;
1308                 r1_bio->sectors = max_sectors;
1309         }
1310
1311         r1_bio->read_disk = rdisk;
1312
1313         if (!r1bio_existed && blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
1314                 r1_bio->start_time = bio_start_io_acct(bio);
1315
1316         read_bio = bio_alloc_clone(mirror->rdev->bdev, bio, gfp,
1317                                    &mddev->bio_set);
1318
1319         r1_bio->bios[rdisk] = read_bio;
1320
1321         read_bio->bi_iter.bi_sector = r1_bio->sector +
1322                 mirror->rdev->data_offset;
1323         read_bio->bi_end_io = raid1_end_read_request;
1324         bio_set_op_attrs(read_bio, op, do_sync);
1325         if (test_bit(FailFast, &mirror->rdev->flags) &&
1326             test_bit(R1BIO_FailFast, &r1_bio->state))
1327                 read_bio->bi_opf |= MD_FAILFAST;
1328         read_bio->bi_private = r1_bio;
1329
1330         if (mddev->gendisk)
1331                 trace_block_bio_remap(read_bio, disk_devt(mddev->gendisk),
1332                                       r1_bio->sector);
1333
1334         submit_bio_noacct(read_bio);
1335 }
1336
1337 static void raid1_write_request(struct mddev *mddev, struct bio *bio,
1338                                 int max_write_sectors)
1339 {
1340         struct r1conf *conf = mddev->private;
1341         struct r1bio *r1_bio;
1342         int i, disks;
1343         struct bitmap *bitmap = mddev->bitmap;
1344         unsigned long flags;
1345         struct md_rdev *blocked_rdev;
1346         struct blk_plug_cb *cb;
1347         struct raid1_plug_cb *plug = NULL;
1348         int first_clone;
1349         int max_sectors;
1350         bool write_behind = false;
1351
1352         if (mddev_is_clustered(mddev) &&
1353              md_cluster_ops->area_resyncing(mddev, WRITE,
1354                      bio->bi_iter.bi_sector, bio_end_sector(bio))) {
1355
1356                 DEFINE_WAIT(w);
1357                 if (bio->bi_opf & REQ_NOWAIT) {
1358                         bio_wouldblock_error(bio);
1359                         return;
1360                 }
1361                 for (;;) {
1362                         prepare_to_wait(&conf->wait_barrier,
1363                                         &w, TASK_IDLE);
1364                         if (!md_cluster_ops->area_resyncing(mddev, WRITE,
1365                                                         bio->bi_iter.bi_sector,
1366                                                         bio_end_sector(bio)))
1367                                 break;
1368                         schedule();
1369                 }
1370                 finish_wait(&conf->wait_barrier, &w);
1371         }
1372
1373         /*
1374          * Register the new request and wait if the reconstruction
1375          * thread has put up a bar for new requests.
1376          * Continue immediately if no resync is active currently.
1377          */
1378         if (!wait_barrier(conf, bio->bi_iter.bi_sector,
1379                                 bio->bi_opf & REQ_NOWAIT)) {
1380                 bio_wouldblock_error(bio);
1381                 return;
1382         }
1383
1384         r1_bio = alloc_r1bio(mddev, bio);
1385         r1_bio->sectors = max_write_sectors;
1386
1387         /* first select target devices under rcu_lock and
1388          * inc refcount on their rdev.  Record them by setting
1389          * bios[x] to bio
1390          * If there are known/acknowledged bad blocks on any device on
1391          * which we have seen a write error, we want to avoid writing those
1392          * blocks.
1393          * This potentially requires several writes to write around
1394          * the bad blocks.  Each set of writes gets it's own r1bio
1395          * with a set of bios attached.
1396          */
1397
1398         disks = conf->raid_disks * 2;
1399  retry_write:
1400         blocked_rdev = NULL;
1401         rcu_read_lock();
1402         max_sectors = r1_bio->sectors;
1403         for (i = 0;  i < disks; i++) {
1404                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1405
1406                 /*
1407                  * The write-behind io is only attempted on drives marked as
1408                  * write-mostly, which means we could allocate write behind
1409                  * bio later.
1410                  */
1411                 if (rdev && test_bit(WriteMostly, &rdev->flags))
1412                         write_behind = true;
1413
1414                 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
1415                         atomic_inc(&rdev->nr_pending);
1416                         blocked_rdev = rdev;
1417                         break;
1418                 }
1419                 r1_bio->bios[i] = NULL;
1420                 if (!rdev || test_bit(Faulty, &rdev->flags)) {
1421                         if (i < conf->raid_disks)
1422                                 set_bit(R1BIO_Degraded, &r1_bio->state);
1423                         continue;
1424                 }
1425
1426                 atomic_inc(&rdev->nr_pending);
1427                 if (test_bit(WriteErrorSeen, &rdev->flags)) {
1428                         sector_t first_bad;
1429                         int bad_sectors;
1430                         int is_bad;
1431
1432                         is_bad = is_badblock(rdev, r1_bio->sector, max_sectors,
1433                                              &first_bad, &bad_sectors);
1434                         if (is_bad < 0) {
1435                                 /* mustn't write here until the bad block is
1436                                  * acknowledged*/
1437                                 set_bit(BlockedBadBlocks, &rdev->flags);
1438                                 blocked_rdev = rdev;
1439                                 break;
1440                         }
1441                         if (is_bad && first_bad <= r1_bio->sector) {
1442                                 /* Cannot write here at all */
1443                                 bad_sectors -= (r1_bio->sector - first_bad);
1444                                 if (bad_sectors < max_sectors)
1445                                         /* mustn't write more than bad_sectors
1446                                          * to other devices yet
1447                                          */
1448                                         max_sectors = bad_sectors;
1449                                 rdev_dec_pending(rdev, mddev);
1450                                 /* We don't set R1BIO_Degraded as that
1451                                  * only applies if the disk is
1452                                  * missing, so it might be re-added,
1453                                  * and we want to know to recover this
1454                                  * chunk.
1455                                  * In this case the device is here,
1456                                  * and the fact that this chunk is not
1457                                  * in-sync is recorded in the bad
1458                                  * block log
1459                                  */
1460                                 continue;
1461                         }
1462                         if (is_bad) {
1463                                 int good_sectors = first_bad - r1_bio->sector;
1464                                 if (good_sectors < max_sectors)
1465                                         max_sectors = good_sectors;
1466                         }
1467                 }
1468                 r1_bio->bios[i] = bio;
1469         }
1470         rcu_read_unlock();
1471
1472         if (unlikely(blocked_rdev)) {
1473                 /* Wait for this device to become unblocked */
1474                 int j;
1475
1476                 for (j = 0; j < i; j++)
1477                         if (r1_bio->bios[j])
1478                                 rdev_dec_pending(conf->mirrors[j].rdev, mddev);
1479                 r1_bio->state = 0;
1480                 allow_barrier(conf, bio->bi_iter.bi_sector);
1481
1482                 if (bio->bi_opf & REQ_NOWAIT) {
1483                         bio_wouldblock_error(bio);
1484                         return;
1485                 }
1486                 raid1_log(mddev, "wait rdev %d blocked", blocked_rdev->raid_disk);
1487                 md_wait_for_blocked_rdev(blocked_rdev, mddev);
1488                 wait_barrier(conf, bio->bi_iter.bi_sector, false);
1489                 goto retry_write;
1490         }
1491
1492         /*
1493          * When using a bitmap, we may call alloc_behind_master_bio below.
1494          * alloc_behind_master_bio allocates a copy of the data payload a page
1495          * at a time and thus needs a new bio that can fit the whole payload
1496          * this bio in page sized chunks.
1497          */
1498         if (write_behind && bitmap)
1499                 max_sectors = min_t(int, max_sectors,
1500                                     BIO_MAX_VECS * (PAGE_SIZE >> 9));
1501         if (max_sectors < bio_sectors(bio)) {
1502                 struct bio *split = bio_split(bio, max_sectors,
1503                                               GFP_NOIO, &conf->bio_split);
1504                 bio_chain(split, bio);
1505                 submit_bio_noacct(bio);
1506                 bio = split;
1507                 r1_bio->master_bio = bio;
1508                 r1_bio->sectors = max_sectors;
1509         }
1510
1511         if (blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
1512                 r1_bio->start_time = bio_start_io_acct(bio);
1513         atomic_set(&r1_bio->remaining, 1);
1514         atomic_set(&r1_bio->behind_remaining, 0);
1515
1516         first_clone = 1;
1517
1518         for (i = 0; i < disks; i++) {
1519                 struct bio *mbio = NULL;
1520                 struct md_rdev *rdev = conf->mirrors[i].rdev;
1521                 if (!r1_bio->bios[i])
1522                         continue;
1523
1524                 if (first_clone) {
1525                         /* do behind I/O ?
1526                          * Not if there are too many, or cannot
1527                          * allocate memory, or a reader on WriteMostly
1528                          * is waiting for behind writes to flush */
1529                         if (bitmap &&
1530                             test_bit(WriteMostly, &rdev->flags) &&
1531                             (atomic_read(&bitmap->behind_writes)
1532                              < mddev->bitmap_info.max_write_behind) &&
1533                             !waitqueue_active(&bitmap->behind_wait)) {
1534                                 alloc_behind_master_bio(r1_bio, bio);
1535                         }
1536
1537                         md_bitmap_startwrite(bitmap, r1_bio->sector, r1_bio->sectors,
1538                                              test_bit(R1BIO_BehindIO, &r1_bio->state));
1539                         first_clone = 0;
1540                 }
1541
1542                 if (r1_bio->behind_master_bio) {
1543                         mbio = bio_alloc_clone(rdev->bdev,
1544                                                r1_bio->behind_master_bio,
1545                                                GFP_NOIO, &mddev->bio_set);
1546                         if (test_bit(CollisionCheck, &rdev->flags))
1547                                 wait_for_serialization(rdev, r1_bio);
1548                         if (test_bit(WriteMostly, &rdev->flags))
1549                                 atomic_inc(&r1_bio->behind_remaining);
1550                 } else {
1551                         mbio = bio_alloc_clone(rdev->bdev, bio, GFP_NOIO,
1552                                                &mddev->bio_set);
1553
1554                         if (mddev->serialize_policy)
1555                                 wait_for_serialization(rdev, r1_bio);
1556                 }
1557
1558                 r1_bio->bios[i] = mbio;
1559
1560                 mbio->bi_iter.bi_sector = (r1_bio->sector + rdev->data_offset);
1561                 mbio->bi_end_io = raid1_end_write_request;
1562                 mbio->bi_opf = bio_op(bio) | (bio->bi_opf & (REQ_SYNC | REQ_FUA));
1563                 if (test_bit(FailFast, &rdev->flags) &&
1564                     !test_bit(WriteMostly, &rdev->flags) &&
1565                     conf->raid_disks - mddev->degraded > 1)
1566                         mbio->bi_opf |= MD_FAILFAST;
1567                 mbio->bi_private = r1_bio;
1568
1569                 atomic_inc(&r1_bio->remaining);
1570
1571                 if (mddev->gendisk)
1572                         trace_block_bio_remap(mbio, disk_devt(mddev->gendisk),
1573                                               r1_bio->sector);
1574                 /* flush_pending_writes() needs access to the rdev so...*/
1575                 mbio->bi_bdev = (void *)rdev;
1576
1577                 cb = blk_check_plugged(raid1_unplug, mddev, sizeof(*plug));
1578                 if (cb)
1579                         plug = container_of(cb, struct raid1_plug_cb, cb);
1580                 else
1581                         plug = NULL;
1582                 if (plug) {
1583                         bio_list_add(&plug->pending, mbio);
1584                 } else {
1585                         spin_lock_irqsave(&conf->device_lock, flags);
1586                         bio_list_add(&conf->pending_bio_list, mbio);
1587                         spin_unlock_irqrestore(&conf->device_lock, flags);
1588                         md_wakeup_thread(mddev->thread);
1589                 }
1590         }
1591
1592         r1_bio_write_done(r1_bio);
1593
1594         /* In case raid1d snuck in to freeze_array */
1595         wake_up(&conf->wait_barrier);
1596 }
1597
1598 static bool raid1_make_request(struct mddev *mddev, struct bio *bio)
1599 {
1600         sector_t sectors;
1601
1602         if (unlikely(bio->bi_opf & REQ_PREFLUSH)
1603             && md_flush_request(mddev, bio))
1604                 return true;
1605
1606         /*
1607          * There is a limit to the maximum size, but
1608          * the read/write handler might find a lower limit
1609          * due to bad blocks.  To avoid multiple splits,
1610          * we pass the maximum number of sectors down
1611          * and let the lower level perform the split.
1612          */
1613         sectors = align_to_barrier_unit_end(
1614                 bio->bi_iter.bi_sector, bio_sectors(bio));
1615
1616         if (bio_data_dir(bio) == READ)
1617                 raid1_read_request(mddev, bio, sectors, NULL);
1618         else {
1619                 if (!md_write_start(mddev,bio))
1620                         return false;
1621                 raid1_write_request(mddev, bio, sectors);
1622         }
1623         return true;
1624 }
1625
1626 static void raid1_status(struct seq_file *seq, struct mddev *mddev)
1627 {
1628         struct r1conf *conf = mddev->private;
1629         int i;
1630
1631         seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1632                    conf->raid_disks - mddev->degraded);
1633         rcu_read_lock();
1634         for (i = 0; i < conf->raid_disks; i++) {
1635                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1636                 seq_printf(seq, "%s",
1637                            rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1638         }
1639         rcu_read_unlock();
1640         seq_printf(seq, "]");
1641 }
1642
1643 /**
1644  * raid1_error() - RAID1 error handler.
1645  * @mddev: affected md device.
1646  * @rdev: member device to fail.
1647  *
1648  * The routine acknowledges &rdev failure and determines new @mddev state.
1649  * If it failed, then:
1650  *      - &MD_BROKEN flag is set in &mddev->flags.
1651  *      - recovery is disabled.
1652  * Otherwise, it must be degraded:
1653  *      - recovery is interrupted.
1654  *      - &mddev->degraded is bumped.
1655  *
1656  * @rdev is marked as &Faulty excluding case when array is failed and
1657  * &mddev->fail_last_dev is off.
1658  */
1659 static void raid1_error(struct mddev *mddev, struct md_rdev *rdev)
1660 {
1661         struct r1conf *conf = mddev->private;
1662         unsigned long flags;
1663
1664         spin_lock_irqsave(&conf->device_lock, flags);
1665
1666         if (test_bit(In_sync, &rdev->flags) &&
1667             (conf->raid_disks - mddev->degraded) == 1) {
1668                 set_bit(MD_BROKEN, &mddev->flags);
1669
1670                 if (!mddev->fail_last_dev) {
1671                         conf->recovery_disabled = mddev->recovery_disabled;
1672                         spin_unlock_irqrestore(&conf->device_lock, flags);
1673                         return;
1674                 }
1675         }
1676         set_bit(Blocked, &rdev->flags);
1677         if (test_and_clear_bit(In_sync, &rdev->flags))
1678                 mddev->degraded++;
1679         set_bit(Faulty, &rdev->flags);
1680         spin_unlock_irqrestore(&conf->device_lock, flags);
1681         /*
1682          * if recovery is running, make sure it aborts.
1683          */
1684         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1685         set_mask_bits(&mddev->sb_flags, 0,
1686                       BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
1687         pr_crit("md/raid1:%s: Disk failure on %pg, disabling device.\n"
1688                 "md/raid1:%s: Operation continuing on %d devices.\n",
1689                 mdname(mddev), rdev->bdev,
1690                 mdname(mddev), conf->raid_disks - mddev->degraded);
1691 }
1692
1693 static void print_conf(struct r1conf *conf)
1694 {
1695         int i;
1696
1697         pr_debug("RAID1 conf printout:\n");
1698         if (!conf) {
1699                 pr_debug("(!conf)\n");
1700                 return;
1701         }
1702         pr_debug(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1703                  conf->raid_disks);
1704
1705         rcu_read_lock();
1706         for (i = 0; i < conf->raid_disks; i++) {
1707                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1708                 if (rdev)
1709                         pr_debug(" disk %d, wo:%d, o:%d, dev:%pg\n",
1710                                  i, !test_bit(In_sync, &rdev->flags),
1711                                  !test_bit(Faulty, &rdev->flags),
1712                                  rdev->bdev);
1713         }
1714         rcu_read_unlock();
1715 }
1716
1717 static void close_sync(struct r1conf *conf)
1718 {
1719         int idx;
1720
1721         for (idx = 0; idx < BARRIER_BUCKETS_NR; idx++) {
1722                 _wait_barrier(conf, idx, false);
1723                 _allow_barrier(conf, idx);
1724         }
1725
1726         mempool_exit(&conf->r1buf_pool);
1727 }
1728
1729 static int raid1_spare_active(struct mddev *mddev)
1730 {
1731         int i;
1732         struct r1conf *conf = mddev->private;
1733         int count = 0;
1734         unsigned long flags;
1735
1736         /*
1737          * Find all failed disks within the RAID1 configuration
1738          * and mark them readable.
1739          * Called under mddev lock, so rcu protection not needed.
1740          * device_lock used to avoid races with raid1_end_read_request
1741          * which expects 'In_sync' flags and ->degraded to be consistent.
1742          */
1743         spin_lock_irqsave(&conf->device_lock, flags);
1744         for (i = 0; i < conf->raid_disks; i++) {
1745                 struct md_rdev *rdev = conf->mirrors[i].rdev;
1746                 struct md_rdev *repl = conf->mirrors[conf->raid_disks + i].rdev;
1747                 if (repl
1748                     && !test_bit(Candidate, &repl->flags)
1749                     && repl->recovery_offset == MaxSector
1750                     && !test_bit(Faulty, &repl->flags)
1751                     && !test_and_set_bit(In_sync, &repl->flags)) {
1752                         /* replacement has just become active */
1753                         if (!rdev ||
1754                             !test_and_clear_bit(In_sync, &rdev->flags))
1755                                 count++;
1756                         if (rdev) {
1757                                 /* Replaced device not technically
1758                                  * faulty, but we need to be sure
1759                                  * it gets removed and never re-added
1760                                  */
1761                                 set_bit(Faulty, &rdev->flags);
1762                                 sysfs_notify_dirent_safe(
1763                                         rdev->sysfs_state);
1764                         }
1765                 }
1766                 if (rdev
1767                     && rdev->recovery_offset == MaxSector
1768                     && !test_bit(Faulty, &rdev->flags)
1769                     && !test_and_set_bit(In_sync, &rdev->flags)) {
1770                         count++;
1771                         sysfs_notify_dirent_safe(rdev->sysfs_state);
1772                 }
1773         }
1774         mddev->degraded -= count;
1775         spin_unlock_irqrestore(&conf->device_lock, flags);
1776
1777         print_conf(conf);
1778         return count;
1779 }
1780
1781 static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
1782 {
1783         struct r1conf *conf = mddev->private;
1784         int err = -EEXIST;
1785         int mirror = 0;
1786         struct raid1_info *p;
1787         int first = 0;
1788         int last = conf->raid_disks - 1;
1789
1790         if (mddev->recovery_disabled == conf->recovery_disabled)
1791                 return -EBUSY;
1792
1793         if (md_integrity_add_rdev(rdev, mddev))
1794                 return -ENXIO;
1795
1796         if (rdev->raid_disk >= 0)
1797                 first = last = rdev->raid_disk;
1798
1799         /*
1800          * find the disk ... but prefer rdev->saved_raid_disk
1801          * if possible.
1802          */
1803         if (rdev->saved_raid_disk >= 0 &&
1804             rdev->saved_raid_disk >= first &&
1805             rdev->saved_raid_disk < conf->raid_disks &&
1806             conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
1807                 first = last = rdev->saved_raid_disk;
1808
1809         for (mirror = first; mirror <= last; mirror++) {
1810                 p = conf->mirrors + mirror;
1811                 if (!p->rdev) {
1812                         if (mddev->gendisk)
1813                                 disk_stack_limits(mddev->gendisk, rdev->bdev,
1814                                                   rdev->data_offset << 9);
1815
1816                         p->head_position = 0;
1817                         rdev->raid_disk = mirror;
1818                         err = 0;
1819                         /* As all devices are equivalent, we don't need a full recovery
1820                          * if this was recently any drive of the array
1821                          */
1822                         if (rdev->saved_raid_disk < 0)
1823                                 conf->fullsync = 1;
1824                         rcu_assign_pointer(p->rdev, rdev);
1825                         break;
1826                 }
1827                 if (test_bit(WantReplacement, &p->rdev->flags) &&
1828                     p[conf->raid_disks].rdev == NULL) {
1829                         /* Add this device as a replacement */
1830                         clear_bit(In_sync, &rdev->flags);
1831                         set_bit(Replacement, &rdev->flags);
1832                         rdev->raid_disk = mirror;
1833                         err = 0;
1834                         conf->fullsync = 1;
1835                         rcu_assign_pointer(p[conf->raid_disks].rdev, rdev);
1836                         break;
1837                 }
1838         }
1839         print_conf(conf);
1840         return err;
1841 }
1842
1843 static int raid1_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
1844 {
1845         struct r1conf *conf = mddev->private;
1846         int err = 0;
1847         int number = rdev->raid_disk;
1848         struct raid1_info *p = conf->mirrors + number;
1849
1850         if (rdev != p->rdev)
1851                 p = conf->mirrors + conf->raid_disks + number;
1852
1853         print_conf(conf);
1854         if (rdev == p->rdev) {
1855                 if (test_bit(In_sync, &rdev->flags) ||
1856                     atomic_read(&rdev->nr_pending)) {
1857                         err = -EBUSY;
1858                         goto abort;
1859                 }
1860                 /* Only remove non-faulty devices if recovery
1861                  * is not possible.
1862                  */
1863                 if (!test_bit(Faulty, &rdev->flags) &&
1864                     mddev->recovery_disabled != conf->recovery_disabled &&
1865                     mddev->degraded < conf->raid_disks) {
1866                         err = -EBUSY;
1867                         goto abort;
1868                 }
1869                 p->rdev = NULL;
1870                 if (!test_bit(RemoveSynchronized, &rdev->flags)) {
1871                         synchronize_rcu();
1872                         if (atomic_read(&rdev->nr_pending)) {
1873                                 /* lost the race, try later */
1874                                 err = -EBUSY;
1875                                 p->rdev = rdev;
1876                                 goto abort;
1877                         }
1878                 }
1879                 if (conf->mirrors[conf->raid_disks + number].rdev) {
1880                         /* We just removed a device that is being replaced.
1881                          * Move down the replacement.  We drain all IO before
1882                          * doing this to avoid confusion.
1883                          */
1884                         struct md_rdev *repl =
1885                                 conf->mirrors[conf->raid_disks + number].rdev;
1886                         freeze_array(conf, 0);
1887                         if (atomic_read(&repl->nr_pending)) {
1888                                 /* It means that some queued IO of retry_list
1889                                  * hold repl. Thus, we cannot set replacement
1890                                  * as NULL, avoiding rdev NULL pointer
1891                                  * dereference in sync_request_write and
1892                                  * handle_write_finished.
1893                                  */
1894                                 err = -EBUSY;
1895                                 unfreeze_array(conf);
1896                                 goto abort;
1897                         }
1898                         clear_bit(Replacement, &repl->flags);
1899                         p->rdev = repl;
1900                         conf->mirrors[conf->raid_disks + number].rdev = NULL;
1901                         unfreeze_array(conf);
1902                 }
1903
1904                 clear_bit(WantReplacement, &rdev->flags);
1905                 err = md_integrity_register(mddev);
1906         }
1907 abort:
1908
1909         print_conf(conf);
1910         return err;
1911 }
1912
1913 static void end_sync_read(struct bio *bio)
1914 {
1915         struct r1bio *r1_bio = get_resync_r1bio(bio);
1916
1917         update_head_pos(r1_bio->read_disk, r1_bio);
1918
1919         /*
1920          * we have read a block, now it needs to be re-written,
1921          * or re-read if the read failed.
1922          * We don't do much here, just schedule handling by raid1d
1923          */
1924         if (!bio->bi_status)
1925                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1926
1927         if (atomic_dec_and_test(&r1_bio->remaining))
1928                 reschedule_retry(r1_bio);
1929 }
1930
1931 static void abort_sync_write(struct mddev *mddev, struct r1bio *r1_bio)
1932 {
1933         sector_t sync_blocks = 0;
1934         sector_t s = r1_bio->sector;
1935         long sectors_to_go = r1_bio->sectors;
1936
1937         /* make sure these bits don't get cleared. */
1938         do {
1939                 md_bitmap_end_sync(mddev->bitmap, s, &sync_blocks, 1);
1940                 s += sync_blocks;
1941                 sectors_to_go -= sync_blocks;
1942         } while (sectors_to_go > 0);
1943 }
1944
1945 static void put_sync_write_buf(struct r1bio *r1_bio, int uptodate)
1946 {
1947         if (atomic_dec_and_test(&r1_bio->remaining)) {
1948                 struct mddev *mddev = r1_bio->mddev;
1949                 int s = r1_bio->sectors;
1950
1951                 if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
1952                     test_bit(R1BIO_WriteError, &r1_bio->state))
1953                         reschedule_retry(r1_bio);
1954                 else {
1955                         put_buf(r1_bio);
1956                         md_done_sync(mddev, s, uptodate);
1957                 }
1958         }
1959 }
1960
1961 static void end_sync_write(struct bio *bio)
1962 {
1963         int uptodate = !bio->bi_status;
1964         struct r1bio *r1_bio = get_resync_r1bio(bio);
1965         struct mddev *mddev = r1_bio->mddev;
1966         struct r1conf *conf = mddev->private;
1967         sector_t first_bad;
1968         int bad_sectors;
1969         struct md_rdev *rdev = conf->mirrors[find_bio_disk(r1_bio, bio)].rdev;
1970
1971         if (!uptodate) {
1972                 abort_sync_write(mddev, r1_bio);
1973                 set_bit(WriteErrorSeen, &rdev->flags);
1974                 if (!test_and_set_bit(WantReplacement, &rdev->flags))
1975                         set_bit(MD_RECOVERY_NEEDED, &
1976                                 mddev->recovery);
1977                 set_bit(R1BIO_WriteError, &r1_bio->state);
1978         } else if (is_badblock(rdev, r1_bio->sector, r1_bio->sectors,
1979                                &first_bad, &bad_sectors) &&
1980                    !is_badblock(conf->mirrors[r1_bio->read_disk].rdev,
1981                                 r1_bio->sector,
1982                                 r1_bio->sectors,
1983                                 &first_bad, &bad_sectors)
1984                 )
1985                 set_bit(R1BIO_MadeGood, &r1_bio->state);
1986
1987         put_sync_write_buf(r1_bio, uptodate);
1988 }
1989
1990 static int r1_sync_page_io(struct md_rdev *rdev, sector_t sector,
1991                             int sectors, struct page *page, int rw)
1992 {
1993         if (sync_page_io(rdev, sector, sectors << 9, page, rw, 0, false))
1994                 /* success */
1995                 return 1;
1996         if (rw == WRITE) {
1997                 set_bit(WriteErrorSeen, &rdev->flags);
1998                 if (!test_and_set_bit(WantReplacement,
1999                                       &rdev->flags))
2000                         set_bit(MD_RECOVERY_NEEDED, &
2001                                 rdev->mddev->recovery);
2002         }
2003         /* need to record an error - either for the block or the device */
2004         if (!rdev_set_badblocks(rdev, sector, sectors, 0))
2005                 md_error(rdev->mddev, rdev);
2006         return 0;
2007 }
2008
2009 static int fix_sync_read_error(struct r1bio *r1_bio)
2010 {
2011         /* Try some synchronous reads of other devices to get
2012          * good data, much like with normal read errors.  Only
2013          * read into the pages we already have so we don't
2014          * need to re-issue the read request.
2015          * We don't need to freeze the array, because being in an
2016          * active sync request, there is no normal IO, and
2017          * no overlapping syncs.
2018          * We don't need to check is_badblock() again as we
2019          * made sure that anything with a bad block in range
2020          * will have bi_end_io clear.
2021          */
2022         struct mddev *mddev = r1_bio->mddev;
2023         struct r1conf *conf = mddev->private;
2024         struct bio *bio = r1_bio->bios[r1_bio->read_disk];
2025         struct page **pages = get_resync_pages(bio)->pages;
2026         sector_t sect = r1_bio->sector;
2027         int sectors = r1_bio->sectors;
2028         int idx = 0;
2029         struct md_rdev *rdev;
2030
2031         rdev = conf->mirrors[r1_bio->read_disk].rdev;
2032         if (test_bit(FailFast, &rdev->flags)) {
2033                 /* Don't try recovering from here - just fail it
2034                  * ... unless it is the last working device of course */
2035                 md_error(mddev, rdev);
2036                 if (test_bit(Faulty, &rdev->flags))
2037                         /* Don't try to read from here, but make sure
2038                          * put_buf does it's thing
2039                          */
2040                         bio->bi_end_io = end_sync_write;
2041         }
2042
2043         while(sectors) {
2044                 int s = sectors;
2045                 int d = r1_bio->read_disk;
2046                 int success = 0;
2047                 int start;
2048
2049                 if (s > (PAGE_SIZE>>9))
2050                         s = PAGE_SIZE >> 9;
2051                 do {
2052                         if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
2053                                 /* No rcu protection needed here devices
2054                                  * can only be removed when no resync is
2055                                  * active, and resync is currently active
2056                                  */
2057                                 rdev = conf->mirrors[d].rdev;
2058                                 if (sync_page_io(rdev, sect, s<<9,
2059                                                  pages[idx],
2060                                                  REQ_OP_READ, 0, false)) {
2061                                         success = 1;
2062                                         break;
2063                                 }
2064                         }
2065                         d++;
2066                         if (d == conf->raid_disks * 2)
2067                                 d = 0;
2068                 } while (!success && d != r1_bio->read_disk);
2069
2070                 if (!success) {
2071                         int abort = 0;
2072                         /* Cannot read from anywhere, this block is lost.
2073                          * Record a bad block on each device.  If that doesn't
2074                          * work just disable and interrupt the recovery.
2075                          * Don't fail devices as that won't really help.
2076                          */
2077                         pr_crit_ratelimited("md/raid1:%s: %pg: unrecoverable I/O read error for block %llu\n",
2078                                             mdname(mddev), bio->bi_bdev,
2079                                             (unsigned long long)r1_bio->sector);
2080                         for (d = 0; d < conf->raid_disks * 2; d++) {
2081                                 rdev = conf->mirrors[d].rdev;
2082                                 if (!rdev || test_bit(Faulty, &rdev->flags))
2083                                         continue;
2084                                 if (!rdev_set_badblocks(rdev, sect, s, 0))
2085                                         abort = 1;
2086                         }
2087                         if (abort) {
2088                                 conf->recovery_disabled =
2089                                         mddev->recovery_disabled;
2090                                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2091                                 md_done_sync(mddev, r1_bio->sectors, 0);
2092                                 put_buf(r1_bio);
2093                                 return 0;
2094                         }
2095                         /* Try next page */
2096                         sectors -= s;
2097                         sect += s;
2098                         idx++;
2099                         continue;
2100                 }
2101
2102                 start = d;
2103                 /* write it back and re-read */
2104                 while (d != r1_bio->read_disk) {
2105                         if (d == 0)
2106                                 d = conf->raid_disks * 2;
2107                         d--;
2108                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
2109                                 continue;
2110                         rdev = conf->mirrors[d].rdev;
2111                         if (r1_sync_page_io(rdev, sect, s,
2112                                             pages[idx],
2113                                             WRITE) == 0) {
2114                                 r1_bio->bios[d]->bi_end_io = NULL;
2115                                 rdev_dec_pending(rdev, mddev);
2116                         }
2117                 }
2118                 d = start;
2119                 while (d != r1_bio->read_disk) {
2120                         if (d == 0)
2121                                 d = conf->raid_disks * 2;
2122                         d--;
2123                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
2124                                 continue;
2125                         rdev = conf->mirrors[d].rdev;
2126                         if (r1_sync_page_io(rdev, sect, s,
2127                                             pages[idx],
2128                                             READ) != 0)
2129                                 atomic_add(s, &rdev->corrected_errors);
2130                 }
2131                 sectors -= s;
2132                 sect += s;
2133                 idx ++;
2134         }
2135         set_bit(R1BIO_Uptodate, &r1_bio->state);
2136         bio->bi_status = 0;
2137         return 1;
2138 }
2139
2140 static void process_checks(struct r1bio *r1_bio)
2141 {
2142         /* We have read all readable devices.  If we haven't
2143          * got the block, then there is no hope left.
2144          * If we have, then we want to do a comparison
2145          * and skip the write if everything is the same.
2146          * If any blocks failed to read, then we need to
2147          * attempt an over-write
2148          */
2149         struct mddev *mddev = r1_bio->mddev;
2150         struct r1conf *conf = mddev->private;
2151         int primary;
2152         int i;
2153         int vcnt;
2154
2155         /* Fix variable parts of all bios */
2156         vcnt = (r1_bio->sectors + PAGE_SIZE / 512 - 1) >> (PAGE_SHIFT - 9);
2157         for (i = 0; i < conf->raid_disks * 2; i++) {
2158                 blk_status_t status;
2159                 struct bio *b = r1_bio->bios[i];
2160                 struct resync_pages *rp = get_resync_pages(b);
2161                 if (b->bi_end_io != end_sync_read)
2162                         continue;
2163                 /* fixup the bio for reuse, but preserve errno */
2164                 status = b->bi_status;
2165                 bio_reset(b, conf->mirrors[i].rdev->bdev, REQ_OP_READ);
2166                 b->bi_status = status;
2167                 b->bi_iter.bi_sector = r1_bio->sector +
2168                         conf->mirrors[i].rdev->data_offset;
2169                 b->bi_end_io = end_sync_read;
2170                 rp->raid_bio = r1_bio;
2171                 b->bi_private = rp;
2172
2173                 /* initialize bvec table again */
2174                 md_bio_reset_resync_pages(b, rp, r1_bio->sectors << 9);
2175         }
2176         for (primary = 0; primary < conf->raid_disks * 2; primary++)
2177                 if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
2178                     !r1_bio->bios[primary]->bi_status) {
2179                         r1_bio->bios[primary]->bi_end_io = NULL;
2180                         rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
2181                         break;
2182                 }
2183         r1_bio->read_disk = primary;
2184         for (i = 0; i < conf->raid_disks * 2; i++) {
2185                 int j = 0;
2186                 struct bio *pbio = r1_bio->bios[primary];
2187                 struct bio *sbio = r1_bio->bios[i];
2188                 blk_status_t status = sbio->bi_status;
2189                 struct page **ppages = get_resync_pages(pbio)->pages;
2190                 struct page **spages = get_resync_pages(sbio)->pages;
2191                 struct bio_vec *bi;
2192                 int page_len[RESYNC_PAGES] = { 0 };
2193                 struct bvec_iter_all iter_all;
2194
2195                 if (sbio->bi_end_io != end_sync_read)
2196                         continue;
2197                 /* Now we can 'fixup' the error value */
2198                 sbio->bi_status = 0;
2199
2200                 bio_for_each_segment_all(bi, sbio, iter_all)
2201                         page_len[j++] = bi->bv_len;
2202
2203                 if (!status) {
2204                         for (j = vcnt; j-- ; ) {
2205                                 if (memcmp(page_address(ppages[j]),
2206                                            page_address(spages[j]),
2207                                            page_len[j]))
2208                                         break;
2209                         }
2210                 } else
2211                         j = 0;
2212                 if (j >= 0)
2213                         atomic64_add(r1_bio->sectors, &mddev->resync_mismatches);
2214                 if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
2215                               && !status)) {
2216                         /* No need to write to this device. */
2217                         sbio->bi_end_io = NULL;
2218                         rdev_dec_pending(conf->mirrors[i].rdev, mddev);
2219                         continue;
2220                 }
2221
2222                 bio_copy_data(sbio, pbio);
2223         }
2224 }
2225
2226 static void sync_request_write(struct mddev *mddev, struct r1bio *r1_bio)
2227 {
2228         struct r1conf *conf = mddev->private;
2229         int i;
2230         int disks = conf->raid_disks * 2;
2231         struct bio *wbio;
2232
2233         if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
2234                 /* ouch - failed to read all of that. */
2235                 if (!fix_sync_read_error(r1_bio))
2236                         return;
2237
2238         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2239                 process_checks(r1_bio);
2240
2241         /*
2242          * schedule writes
2243          */
2244         atomic_set(&r1_bio->remaining, 1);
2245         for (i = 0; i < disks ; i++) {
2246                 wbio = r1_bio->bios[i];
2247                 if (wbio->bi_end_io == NULL ||
2248                     (wbio->bi_end_io == end_sync_read &&
2249                      (i == r1_bio->read_disk ||
2250                       !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
2251                         continue;
2252                 if (test_bit(Faulty, &conf->mirrors[i].rdev->flags)) {
2253                         abort_sync_write(mddev, r1_bio);
2254                         continue;
2255                 }
2256
2257                 bio_set_op_attrs(wbio, REQ_OP_WRITE, 0);
2258                 if (test_bit(FailFast, &conf->mirrors[i].rdev->flags))
2259                         wbio->bi_opf |= MD_FAILFAST;
2260
2261                 wbio->bi_end_io = end_sync_write;
2262                 atomic_inc(&r1_bio->remaining);
2263                 md_sync_acct(conf->mirrors[i].rdev->bdev, bio_sectors(wbio));
2264
2265                 submit_bio_noacct(wbio);
2266         }
2267
2268         put_sync_write_buf(r1_bio, 1);
2269 }
2270
2271 /*
2272  * This is a kernel thread which:
2273  *
2274  *      1.      Retries failed read operations on working mirrors.
2275  *      2.      Updates the raid superblock when problems encounter.
2276  *      3.      Performs writes following reads for array synchronising.
2277  */
2278
2279 static void fix_read_error(struct r1conf *conf, int read_disk,
2280                            sector_t sect, int sectors)
2281 {
2282         struct mddev *mddev = conf->mddev;
2283         while(sectors) {
2284                 int s = sectors;
2285                 int d = read_disk;
2286                 int success = 0;
2287                 int start;
2288                 struct md_rdev *rdev;
2289
2290                 if (s > (PAGE_SIZE>>9))
2291                         s = PAGE_SIZE >> 9;
2292
2293                 do {
2294                         sector_t first_bad;
2295                         int bad_sectors;
2296
2297                         rcu_read_lock();
2298                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2299                         if (rdev &&
2300                             (test_bit(In_sync, &rdev->flags) ||
2301                              (!test_bit(Faulty, &rdev->flags) &&
2302                               rdev->recovery_offset >= sect + s)) &&
2303                             is_badblock(rdev, sect, s,
2304                                         &first_bad, &bad_sectors) == 0) {
2305                                 atomic_inc(&rdev->nr_pending);
2306                                 rcu_read_unlock();
2307                                 if (sync_page_io(rdev, sect, s<<9,
2308                                          conf->tmppage, REQ_OP_READ, 0, false))
2309                                         success = 1;
2310                                 rdev_dec_pending(rdev, mddev);
2311                                 if (success)
2312                                         break;
2313                         } else
2314                                 rcu_read_unlock();
2315                         d++;
2316                         if (d == conf->raid_disks * 2)
2317                                 d = 0;
2318                 } while (!success && d != read_disk);
2319
2320                 if (!success) {
2321                         /* Cannot read from anywhere - mark it bad */
2322                         struct md_rdev *rdev = conf->mirrors[read_disk].rdev;
2323                         if (!rdev_set_badblocks(rdev, sect, s, 0))
2324                                 md_error(mddev, rdev);
2325                         break;
2326                 }
2327                 /* write it back and re-read */
2328                 start = d;
2329                 while (d != read_disk) {
2330                         if (d==0)
2331                                 d = conf->raid_disks * 2;
2332                         d--;
2333                         rcu_read_lock();
2334                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2335                         if (rdev &&
2336                             !test_bit(Faulty, &rdev->flags)) {
2337                                 atomic_inc(&rdev->nr_pending);
2338                                 rcu_read_unlock();
2339                                 r1_sync_page_io(rdev, sect, s,
2340                                                 conf->tmppage, WRITE);
2341                                 rdev_dec_pending(rdev, mddev);
2342                         } else
2343                                 rcu_read_unlock();
2344                 }
2345                 d = start;
2346                 while (d != read_disk) {
2347                         if (d==0)
2348                                 d = conf->raid_disks * 2;
2349                         d--;
2350                         rcu_read_lock();
2351                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2352                         if (rdev &&
2353                             !test_bit(Faulty, &rdev->flags)) {
2354                                 atomic_inc(&rdev->nr_pending);
2355                                 rcu_read_unlock();
2356                                 if (r1_sync_page_io(rdev, sect, s,
2357                                                     conf->tmppage, READ)) {
2358                                         atomic_add(s, &rdev->corrected_errors);
2359                                         pr_info("md/raid1:%s: read error corrected (%d sectors at %llu on %pg)\n",
2360                                                 mdname(mddev), s,
2361                                                 (unsigned long long)(sect +
2362                                                                      rdev->data_offset),
2363                                                 rdev->bdev);
2364                                 }
2365                                 rdev_dec_pending(rdev, mddev);
2366                         } else
2367                                 rcu_read_unlock();
2368                 }
2369                 sectors -= s;
2370                 sect += s;
2371         }
2372 }
2373
2374 static int narrow_write_error(struct r1bio *r1_bio, int i)
2375 {
2376         struct mddev *mddev = r1_bio->mddev;
2377         struct r1conf *conf = mddev->private;
2378         struct md_rdev *rdev = conf->mirrors[i].rdev;
2379
2380         /* bio has the data to be written to device 'i' where
2381          * we just recently had a write error.
2382          * We repeatedly clone the bio and trim down to one block,
2383          * then try the write.  Where the write fails we record
2384          * a bad block.
2385          * It is conceivable that the bio doesn't exactly align with
2386          * blocks.  We must handle this somehow.
2387          *
2388          * We currently own a reference on the rdev.
2389          */
2390
2391         int block_sectors;
2392         sector_t sector;
2393         int sectors;
2394         int sect_to_write = r1_bio->sectors;
2395         int ok = 1;
2396
2397         if (rdev->badblocks.shift < 0)
2398                 return 0;
2399
2400         block_sectors = roundup(1 << rdev->badblocks.shift,
2401                                 bdev_logical_block_size(rdev->bdev) >> 9);
2402         sector = r1_bio->sector;
2403         sectors = ((sector + block_sectors)
2404                    & ~(sector_t)(block_sectors - 1))
2405                 - sector;
2406
2407         while (sect_to_write) {
2408                 struct bio *wbio;
2409                 if (sectors > sect_to_write)
2410                         sectors = sect_to_write;
2411                 /* Write at 'sector' for 'sectors'*/
2412
2413                 if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
2414                         wbio = bio_alloc_clone(rdev->bdev,
2415                                                r1_bio->behind_master_bio,
2416                                                GFP_NOIO, &mddev->bio_set);
2417                 } else {
2418                         wbio = bio_alloc_clone(rdev->bdev, r1_bio->master_bio,
2419                                                GFP_NOIO, &mddev->bio_set);
2420                 }
2421
2422                 bio_set_op_attrs(wbio, REQ_OP_WRITE, 0);
2423                 wbio->bi_iter.bi_sector = r1_bio->sector;
2424                 wbio->bi_iter.bi_size = r1_bio->sectors << 9;
2425
2426                 bio_trim(wbio, sector - r1_bio->sector, sectors);
2427                 wbio->bi_iter.bi_sector += rdev->data_offset;
2428
2429                 if (submit_bio_wait(wbio) < 0)
2430                         /* failure! */
2431                         ok = rdev_set_badblocks(rdev, sector,
2432                                                 sectors, 0)
2433                                 && ok;
2434
2435                 bio_put(wbio);
2436                 sect_to_write -= sectors;
2437                 sector += sectors;
2438                 sectors = block_sectors;
2439         }
2440         return ok;
2441 }
2442
2443 static void handle_sync_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2444 {
2445         int m;
2446         int s = r1_bio->sectors;
2447         for (m = 0; m < conf->raid_disks * 2 ; m++) {
2448                 struct md_rdev *rdev = conf->mirrors[m].rdev;
2449                 struct bio *bio = r1_bio->bios[m];
2450                 if (bio->bi_end_io == NULL)
2451                         continue;
2452                 if (!bio->bi_status &&
2453                     test_bit(R1BIO_MadeGood, &r1_bio->state)) {
2454                         rdev_clear_badblocks(rdev, r1_bio->sector, s, 0);
2455                 }
2456                 if (bio->bi_status &&
2457                     test_bit(R1BIO_WriteError, &r1_bio->state)) {
2458                         if (!rdev_set_badblocks(rdev, r1_bio->sector, s, 0))
2459                                 md_error(conf->mddev, rdev);
2460                 }
2461         }
2462         put_buf(r1_bio);
2463         md_done_sync(conf->mddev, s, 1);
2464 }
2465
2466 static void handle_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2467 {
2468         int m, idx;
2469         bool fail = false;
2470
2471         for (m = 0; m < conf->raid_disks * 2 ; m++)
2472                 if (r1_bio->bios[m] == IO_MADE_GOOD) {
2473                         struct md_rdev *rdev = conf->mirrors[m].rdev;
2474                         rdev_clear_badblocks(rdev,
2475                                              r1_bio->sector,
2476                                              r1_bio->sectors, 0);
2477                         rdev_dec_pending(rdev, conf->mddev);
2478                 } else if (r1_bio->bios[m] != NULL) {
2479                         /* This drive got a write error.  We need to
2480                          * narrow down and record precise write
2481                          * errors.
2482                          */
2483                         fail = true;
2484                         if (!narrow_write_error(r1_bio, m)) {
2485                                 md_error(conf->mddev,
2486                                          conf->mirrors[m].rdev);
2487                                 /* an I/O failed, we can't clear the bitmap */
2488                                 set_bit(R1BIO_Degraded, &r1_bio->state);
2489                         }
2490                         rdev_dec_pending(conf->mirrors[m].rdev,
2491                                          conf->mddev);
2492                 }
2493         if (fail) {
2494                 spin_lock_irq(&conf->device_lock);
2495                 list_add(&r1_bio->retry_list, &conf->bio_end_io_list);
2496                 idx = sector_to_idx(r1_bio->sector);
2497                 atomic_inc(&conf->nr_queued[idx]);
2498                 spin_unlock_irq(&conf->device_lock);
2499                 /*
2500                  * In case freeze_array() is waiting for condition
2501                  * get_unqueued_pending() == extra to be true.
2502                  */
2503                 wake_up(&conf->wait_barrier);
2504                 md_wakeup_thread(conf->mddev->thread);
2505         } else {
2506                 if (test_bit(R1BIO_WriteError, &r1_bio->state))
2507                         close_write(r1_bio);
2508                 raid_end_bio_io(r1_bio);
2509         }
2510 }
2511
2512 static void handle_read_error(struct r1conf *conf, struct r1bio *r1_bio)
2513 {
2514         struct mddev *mddev = conf->mddev;
2515         struct bio *bio;
2516         struct md_rdev *rdev;
2517
2518         clear_bit(R1BIO_ReadError, &r1_bio->state);
2519         /* we got a read error. Maybe the drive is bad.  Maybe just
2520          * the block and we can fix it.
2521          * We freeze all other IO, and try reading the block from
2522          * other devices.  When we find one, we re-write
2523          * and check it that fixes the read error.
2524          * This is all done synchronously while the array is
2525          * frozen
2526          */
2527
2528         bio = r1_bio->bios[r1_bio->read_disk];
2529         bio_put(bio);
2530         r1_bio->bios[r1_bio->read_disk] = NULL;
2531
2532         rdev = conf->mirrors[r1_bio->read_disk].rdev;
2533         if (mddev->ro == 0
2534             && !test_bit(FailFast, &rdev->flags)) {
2535                 freeze_array(conf, 1);
2536                 fix_read_error(conf, r1_bio->read_disk,
2537                                r1_bio->sector, r1_bio->sectors);
2538                 unfreeze_array(conf);
2539         } else if (mddev->ro == 0 && test_bit(FailFast, &rdev->flags)) {
2540                 md_error(mddev, rdev);
2541         } else {
2542                 r1_bio->bios[r1_bio->read_disk] = IO_BLOCKED;
2543         }
2544
2545         rdev_dec_pending(rdev, conf->mddev);
2546         allow_barrier(conf, r1_bio->sector);
2547         bio = r1_bio->master_bio;
2548
2549         /* Reuse the old r1_bio so that the IO_BLOCKED settings are preserved */
2550         r1_bio->state = 0;
2551         raid1_read_request(mddev, bio, r1_bio->sectors, r1_bio);
2552 }
2553
2554 static void raid1d(struct md_thread *thread)
2555 {
2556         struct mddev *mddev = thread->mddev;
2557         struct r1bio *r1_bio;
2558         unsigned long flags;
2559         struct r1conf *conf = mddev->private;
2560         struct list_head *head = &conf->retry_list;
2561         struct blk_plug plug;
2562         int idx;
2563
2564         md_check_recovery(mddev);
2565
2566         if (!list_empty_careful(&conf->bio_end_io_list) &&
2567             !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
2568                 LIST_HEAD(tmp);
2569                 spin_lock_irqsave(&conf->device_lock, flags);
2570                 if (!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags))
2571                         list_splice_init(&conf->bio_end_io_list, &tmp);
2572                 spin_unlock_irqrestore(&conf->device_lock, flags);
2573                 while (!list_empty(&tmp)) {
2574                         r1_bio = list_first_entry(&tmp, struct r1bio,
2575                                                   retry_list);
2576                         list_del(&r1_bio->retry_list);
2577                         idx = sector_to_idx(r1_bio->sector);
2578                         atomic_dec(&conf->nr_queued[idx]);
2579                         if (mddev->degraded)
2580                                 set_bit(R1BIO_Degraded, &r1_bio->state);
2581                         if (test_bit(R1BIO_WriteError, &r1_bio->state))
2582                                 close_write(r1_bio);
2583                         raid_end_bio_io(r1_bio);
2584                 }
2585         }
2586
2587         blk_start_plug(&plug);
2588         for (;;) {
2589
2590                 flush_pending_writes(conf);
2591
2592                 spin_lock_irqsave(&conf->device_lock, flags);
2593                 if (list_empty(head)) {
2594                         spin_unlock_irqrestore(&conf->device_lock, flags);
2595                         break;
2596                 }
2597                 r1_bio = list_entry(head->prev, struct r1bio, retry_list);
2598                 list_del(head->prev);
2599                 idx = sector_to_idx(r1_bio->sector);
2600                 atomic_dec(&conf->nr_queued[idx]);
2601                 spin_unlock_irqrestore(&conf->device_lock, flags);
2602
2603                 mddev = r1_bio->mddev;
2604                 conf = mddev->private;
2605                 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
2606                         if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2607                             test_bit(R1BIO_WriteError, &r1_bio->state))
2608                                 handle_sync_write_finished(conf, r1_bio);
2609                         else
2610                                 sync_request_write(mddev, r1_bio);
2611                 } else if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2612                            test_bit(R1BIO_WriteError, &r1_bio->state))
2613                         handle_write_finished(conf, r1_bio);
2614                 else if (test_bit(R1BIO_ReadError, &r1_bio->state))
2615                         handle_read_error(conf, r1_bio);
2616                 else
2617                         WARN_ON_ONCE(1);
2618
2619                 cond_resched();
2620                 if (mddev->sb_flags & ~(1<<MD_SB_CHANGE_PENDING))
2621                         md_check_recovery(mddev);
2622         }
2623         blk_finish_plug(&plug);
2624 }
2625
2626 static int init_resync(struct r1conf *conf)
2627 {
2628         int buffs;
2629
2630         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
2631         BUG_ON(mempool_initialized(&conf->r1buf_pool));
2632
2633         return mempool_init(&conf->r1buf_pool, buffs, r1buf_pool_alloc,
2634                             r1buf_pool_free, conf->poolinfo);
2635 }
2636
2637 static struct r1bio *raid1_alloc_init_r1buf(struct r1conf *conf)
2638 {
2639         struct r1bio *r1bio = mempool_alloc(&conf->r1buf_pool, GFP_NOIO);
2640         struct resync_pages *rps;
2641         struct bio *bio;
2642         int i;
2643
2644         for (i = conf->poolinfo->raid_disks; i--; ) {
2645                 bio = r1bio->bios[i];
2646                 rps = bio->bi_private;
2647                 bio_reset(bio, NULL, 0);
2648                 bio->bi_private = rps;
2649         }
2650         r1bio->master_bio = NULL;
2651         return r1bio;
2652 }
2653
2654 /*
2655  * perform a "sync" on one "block"
2656  *
2657  * We need to make sure that no normal I/O request - particularly write
2658  * requests - conflict with active sync requests.
2659  *
2660  * This is achieved by tracking pending requests and a 'barrier' concept
2661  * that can be installed to exclude normal IO requests.
2662  */
2663
2664 static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr,
2665                                    int *skipped)
2666 {
2667         struct r1conf *conf = mddev->private;
2668         struct r1bio *r1_bio;
2669         struct bio *bio;
2670         sector_t max_sector, nr_sectors;
2671         int disk = -1;
2672         int i;
2673         int wonly = -1;
2674         int write_targets = 0, read_targets = 0;
2675         sector_t sync_blocks;
2676         int still_degraded = 0;
2677         int good_sectors = RESYNC_SECTORS;
2678         int min_bad = 0; /* number of sectors that are bad in all devices */
2679         int idx = sector_to_idx(sector_nr);
2680         int page_idx = 0;
2681
2682         if (!mempool_initialized(&conf->r1buf_pool))
2683                 if (init_resync(conf))
2684                         return 0;
2685
2686         max_sector = mddev->dev_sectors;
2687         if (sector_nr >= max_sector) {
2688                 /* If we aborted, we need to abort the
2689                  * sync on the 'current' bitmap chunk (there will
2690                  * only be one in raid1 resync.
2691                  * We can find the current addess in mddev->curr_resync
2692                  */
2693                 if (mddev->curr_resync < max_sector) /* aborted */
2694                         md_bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
2695                                            &sync_blocks, 1);
2696                 else /* completed sync */
2697                         conf->fullsync = 0;
2698
2699                 md_bitmap_close_sync(mddev->bitmap);
2700                 close_sync(conf);
2701
2702                 if (mddev_is_clustered(mddev)) {
2703                         conf->cluster_sync_low = 0;
2704                         conf->cluster_sync_high = 0;
2705                 }
2706                 return 0;
2707         }
2708
2709         if (mddev->bitmap == NULL &&
2710             mddev->recovery_cp == MaxSector &&
2711             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
2712             conf->fullsync == 0) {
2713                 *skipped = 1;
2714                 return max_sector - sector_nr;
2715         }
2716         /* before building a request, check if we can skip these blocks..
2717          * This call the bitmap_start_sync doesn't actually record anything
2718          */
2719         if (!md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
2720             !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2721                 /* We can skip this block, and probably several more */
2722                 *skipped = 1;
2723                 return sync_blocks;
2724         }
2725
2726         /*
2727          * If there is non-resync activity waiting for a turn, then let it
2728          * though before starting on this new sync request.
2729          */
2730         if (atomic_read(&conf->nr_waiting[idx]))
2731                 schedule_timeout_uninterruptible(1);
2732
2733         /* we are incrementing sector_nr below. To be safe, we check against
2734          * sector_nr + two times RESYNC_SECTORS
2735          */
2736
2737         md_bitmap_cond_end_sync(mddev->bitmap, sector_nr,
2738                 mddev_is_clustered(mddev) && (sector_nr + 2 * RESYNC_SECTORS > conf->cluster_sync_high));
2739
2740
2741         if (raise_barrier(conf, sector_nr))
2742                 return 0;
2743
2744         r1_bio = raid1_alloc_init_r1buf(conf);
2745
2746         rcu_read_lock();
2747         /*
2748          * If we get a correctably read error during resync or recovery,
2749          * we might want to read from a different device.  So we
2750          * flag all drives that could conceivably be read from for READ,
2751          * and any others (which will be non-In_sync devices) for WRITE.
2752          * If a read fails, we try reading from something else for which READ
2753          * is OK.
2754          */
2755
2756         r1_bio->mddev = mddev;
2757         r1_bio->sector = sector_nr;
2758         r1_bio->state = 0;
2759         set_bit(R1BIO_IsSync, &r1_bio->state);
2760         /* make sure good_sectors won't go across barrier unit boundary */
2761         good_sectors = align_to_barrier_unit_end(sector_nr, good_sectors);
2762
2763         for (i = 0; i < conf->raid_disks * 2; i++) {
2764                 struct md_rdev *rdev;
2765                 bio = r1_bio->bios[i];
2766
2767                 rdev = rcu_dereference(conf->mirrors[i].rdev);
2768                 if (rdev == NULL ||
2769                     test_bit(Faulty, &rdev->flags)) {
2770                         if (i < conf->raid_disks)
2771                                 still_degraded = 1;
2772                 } else if (!test_bit(In_sync, &rdev->flags)) {
2773                         bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
2774                         bio->bi_end_io = end_sync_write;
2775                         write_targets ++;
2776                 } else {
2777                         /* may need to read from here */
2778                         sector_t first_bad = MaxSector;
2779                         int bad_sectors;
2780
2781                         if (is_badblock(rdev, sector_nr, good_sectors,
2782                                         &first_bad, &bad_sectors)) {
2783                                 if (first_bad > sector_nr)
2784                                         good_sectors = first_bad - sector_nr;
2785                                 else {
2786                                         bad_sectors -= (sector_nr - first_bad);
2787                                         if (min_bad == 0 ||
2788                                             min_bad > bad_sectors)
2789                                                 min_bad = bad_sectors;
2790                                 }
2791                         }
2792                         if (sector_nr < first_bad) {
2793                                 if (test_bit(WriteMostly, &rdev->flags)) {
2794                                         if (wonly < 0)
2795                                                 wonly = i;
2796                                 } else {
2797                                         if (disk < 0)
2798                                                 disk = i;
2799                                 }
2800                                 bio_set_op_attrs(bio, REQ_OP_READ, 0);
2801                                 bio->bi_end_io = end_sync_read;
2802                                 read_targets++;
2803                         } else if (!test_bit(WriteErrorSeen, &rdev->flags) &&
2804                                 test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
2805                                 !test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) {
2806                                 /*
2807                                  * The device is suitable for reading (InSync),
2808                                  * but has bad block(s) here. Let's try to correct them,
2809                                  * if we are doing resync or repair. Otherwise, leave
2810                                  * this device alone for this sync request.
2811                                  */
2812                                 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
2813                                 bio->bi_end_io = end_sync_write;
2814                                 write_targets++;
2815                         }
2816                 }
2817                 if (rdev && bio->bi_end_io) {
2818                         atomic_inc(&rdev->nr_pending);
2819                         bio->bi_iter.bi_sector = sector_nr + rdev->data_offset;
2820                         bio_set_dev(bio, rdev->bdev);
2821                         if (test_bit(FailFast, &rdev->flags))
2822                                 bio->bi_opf |= MD_FAILFAST;
2823                 }
2824         }
2825         rcu_read_unlock();
2826         if (disk < 0)
2827                 disk = wonly;
2828         r1_bio->read_disk = disk;
2829
2830         if (read_targets == 0 && min_bad > 0) {
2831                 /* These sectors are bad on all InSync devices, so we
2832                  * need to mark them bad on all write targets
2833                  */
2834                 int ok = 1;
2835                 for (i = 0 ; i < conf->raid_disks * 2 ; i++)
2836                         if (r1_bio->bios[i]->bi_end_io == end_sync_write) {
2837                                 struct md_rdev *rdev = conf->mirrors[i].rdev;
2838                                 ok = rdev_set_badblocks(rdev, sector_nr,
2839                                                         min_bad, 0
2840                                         ) && ok;
2841                         }
2842                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
2843                 *skipped = 1;
2844                 put_buf(r1_bio);
2845
2846                 if (!ok) {
2847                         /* Cannot record the badblocks, so need to
2848                          * abort the resync.
2849                          * If there are multiple read targets, could just
2850                          * fail the really bad ones ???
2851                          */
2852                         conf->recovery_disabled = mddev->recovery_disabled;
2853                         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2854                         return 0;
2855                 } else
2856                         return min_bad;
2857
2858         }
2859         if (min_bad > 0 && min_bad < good_sectors) {
2860                 /* only resync enough to reach the next bad->good
2861                  * transition */
2862                 good_sectors = min_bad;
2863         }
2864
2865         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
2866                 /* extra read targets are also write targets */
2867                 write_targets += read_targets-1;
2868
2869         if (write_targets == 0 || read_targets == 0) {
2870                 /* There is nowhere to write, so all non-sync
2871                  * drives must be failed - so we are finished
2872                  */
2873                 sector_t rv;
2874                 if (min_bad > 0)
2875                         max_sector = sector_nr + min_bad;
2876                 rv = max_sector - sector_nr;
2877                 *skipped = 1;
2878                 put_buf(r1_bio);
2879                 return rv;
2880         }
2881
2882         if (max_sector > mddev->resync_max)
2883                 max_sector = mddev->resync_max; /* Don't do IO beyond here */
2884         if (max_sector > sector_nr + good_sectors)
2885                 max_sector = sector_nr + good_sectors;
2886         nr_sectors = 0;
2887         sync_blocks = 0;
2888         do {
2889                 struct page *page;
2890                 int len = PAGE_SIZE;
2891                 if (sector_nr + (len>>9) > max_sector)
2892                         len = (max_sector - sector_nr) << 9;
2893                 if (len == 0)
2894                         break;
2895                 if (sync_blocks == 0) {
2896                         if (!md_bitmap_start_sync(mddev->bitmap, sector_nr,
2897                                                   &sync_blocks, still_degraded) &&
2898                             !conf->fullsync &&
2899                             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2900                                 break;
2901                         if ((len >> 9) > sync_blocks)
2902                                 len = sync_blocks<<9;
2903                 }
2904
2905                 for (i = 0 ; i < conf->raid_disks * 2; i++) {
2906                         struct resync_pages *rp;
2907
2908                         bio = r1_bio->bios[i];
2909                         rp = get_resync_pages(bio);
2910                         if (bio->bi_end_io) {
2911                                 page = resync_fetch_page(rp, page_idx);
2912
2913                                 /*
2914                                  * won't fail because the vec table is big
2915                                  * enough to hold all these pages
2916                                  */
2917                                 bio_add_page(bio, page, len, 0);
2918                         }
2919                 }
2920                 nr_sectors += len>>9;
2921                 sector_nr += len>>9;
2922                 sync_blocks -= (len>>9);
2923         } while (++page_idx < RESYNC_PAGES);
2924
2925         r1_bio->sectors = nr_sectors;
2926
2927         if (mddev_is_clustered(mddev) &&
2928                         conf->cluster_sync_high < sector_nr + nr_sectors) {
2929                 conf->cluster_sync_low = mddev->curr_resync_completed;
2930                 conf->cluster_sync_high = conf->cluster_sync_low + CLUSTER_RESYNC_WINDOW_SECTORS;
2931                 /* Send resync message */
2932                 md_cluster_ops->resync_info_update(mddev,
2933                                 conf->cluster_sync_low,
2934                                 conf->cluster_sync_high);
2935         }
2936
2937         /* For a user-requested sync, we read all readable devices and do a
2938          * compare
2939          */
2940         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2941                 atomic_set(&r1_bio->remaining, read_targets);
2942                 for (i = 0; i < conf->raid_disks * 2 && read_targets; i++) {
2943                         bio = r1_bio->bios[i];
2944                         if (bio->bi_end_io == end_sync_read) {
2945                                 read_targets--;
2946                                 md_sync_acct_bio(bio, nr_sectors);
2947                                 if (read_targets == 1)
2948                                         bio->bi_opf &= ~MD_FAILFAST;
2949                                 submit_bio_noacct(bio);
2950                         }
2951                 }
2952         } else {
2953                 atomic_set(&r1_bio->remaining, 1);
2954                 bio = r1_bio->bios[r1_bio->read_disk];
2955                 md_sync_acct_bio(bio, nr_sectors);
2956                 if (read_targets == 1)
2957                         bio->bi_opf &= ~MD_FAILFAST;
2958                 submit_bio_noacct(bio);
2959         }
2960         return nr_sectors;
2961 }
2962
2963 static sector_t raid1_size(struct mddev *mddev, sector_t sectors, int raid_disks)
2964 {
2965         if (sectors)
2966                 return sectors;
2967
2968         return mddev->dev_sectors;
2969 }
2970
2971 static struct r1conf *setup_conf(struct mddev *mddev)
2972 {
2973         struct r1conf *conf;
2974         int i;
2975         struct raid1_info *disk;
2976         struct md_rdev *rdev;
2977         int err = -ENOMEM;
2978
2979         conf = kzalloc(sizeof(struct r1conf), GFP_KERNEL);
2980         if (!conf)
2981                 goto abort;
2982
2983         conf->nr_pending = kcalloc(BARRIER_BUCKETS_NR,
2984                                    sizeof(atomic_t), GFP_KERNEL);
2985         if (!conf->nr_pending)
2986                 goto abort;
2987
2988         conf->nr_waiting = kcalloc(BARRIER_BUCKETS_NR,
2989                                    sizeof(atomic_t), GFP_KERNEL);
2990         if (!conf->nr_waiting)
2991                 goto abort;
2992
2993         conf->nr_queued = kcalloc(BARRIER_BUCKETS_NR,
2994                                   sizeof(atomic_t), GFP_KERNEL);
2995         if (!conf->nr_queued)
2996                 goto abort;
2997
2998         conf->barrier = kcalloc(BARRIER_BUCKETS_NR,
2999                                 sizeof(atomic_t), GFP_KERNEL);
3000         if (!conf->barrier)
3001                 goto abort;
3002
3003         conf->mirrors = kzalloc(array3_size(sizeof(struct raid1_info),
3004                                             mddev->raid_disks, 2),
3005                                 GFP_KERNEL);
3006         if (!conf->mirrors)
3007                 goto abort;
3008
3009         conf->tmppage = alloc_page(GFP_KERNEL);
3010         if (!conf->tmppage)
3011                 goto abort;
3012
3013         conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
3014         if (!conf->poolinfo)
3015                 goto abort;
3016         conf->poolinfo->raid_disks = mddev->raid_disks * 2;
3017         err = mempool_init(&conf->r1bio_pool, NR_RAID_BIOS, r1bio_pool_alloc,
3018                            rbio_pool_free, conf->poolinfo);
3019         if (err)
3020                 goto abort;
3021
3022         err = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
3023         if (err)
3024                 goto abort;
3025
3026         conf->poolinfo->mddev = mddev;
3027
3028         err = -EINVAL;
3029         spin_lock_init(&conf->device_lock);
3030         rdev_for_each(rdev, mddev) {
3031                 int disk_idx = rdev->raid_disk;
3032                 if (disk_idx >= mddev->raid_disks
3033                     || disk_idx < 0)
3034                         continue;
3035                 if (test_bit(Replacement, &rdev->flags))
3036                         disk = conf->mirrors + mddev->raid_disks + disk_idx;
3037                 else
3038                         disk = conf->mirrors + disk_idx;
3039
3040                 if (disk->rdev)
3041                         goto abort;
3042                 disk->rdev = rdev;
3043                 disk->head_position = 0;
3044                 disk->seq_start = MaxSector;
3045         }
3046         conf->raid_disks = mddev->raid_disks;
3047         conf->mddev = mddev;
3048         INIT_LIST_HEAD(&conf->retry_list);
3049         INIT_LIST_HEAD(&conf->bio_end_io_list);
3050
3051         spin_lock_init(&conf->resync_lock);
3052         init_waitqueue_head(&conf->wait_barrier);
3053
3054         bio_list_init(&conf->pending_bio_list);
3055         conf->recovery_disabled = mddev->recovery_disabled - 1;
3056
3057         err = -EIO;
3058         for (i = 0; i < conf->raid_disks * 2; i++) {
3059
3060                 disk = conf->mirrors + i;
3061
3062                 if (i < conf->raid_disks &&
3063                     disk[conf->raid_disks].rdev) {
3064                         /* This slot has a replacement. */
3065                         if (!disk->rdev) {
3066                                 /* No original, just make the replacement
3067                                  * a recovering spare
3068                                  */
3069                                 disk->rdev =
3070                                         disk[conf->raid_disks].rdev;
3071                                 disk[conf->raid_disks].rdev = NULL;
3072                         } else if (!test_bit(In_sync, &disk->rdev->flags))
3073                                 /* Original is not in_sync - bad */
3074                                 goto abort;
3075                 }
3076
3077                 if (!disk->rdev ||
3078                     !test_bit(In_sync, &disk->rdev->flags)) {
3079                         disk->head_position = 0;
3080                         if (disk->rdev &&
3081                             (disk->rdev->saved_raid_disk < 0))
3082                                 conf->fullsync = 1;
3083                 }
3084         }
3085
3086         err = -ENOMEM;
3087         conf->thread = md_register_thread(raid1d, mddev, "raid1");
3088         if (!conf->thread)
3089                 goto abort;
3090
3091         return conf;
3092
3093  abort:
3094         if (conf) {
3095                 mempool_exit(&conf->r1bio_pool);
3096                 kfree(conf->mirrors);
3097                 safe_put_page(conf->tmppage);
3098                 kfree(conf->poolinfo);
3099                 kfree(conf->nr_pending);
3100                 kfree(conf->nr_waiting);
3101                 kfree(conf->nr_queued);
3102                 kfree(conf->barrier);
3103                 bioset_exit(&conf->bio_split);
3104                 kfree(conf);
3105         }
3106         return ERR_PTR(err);
3107 }
3108
3109 static void raid1_free(struct mddev *mddev, void *priv);
3110 static int raid1_run(struct mddev *mddev)
3111 {
3112         struct r1conf *conf;
3113         int i;
3114         struct md_rdev *rdev;
3115         int ret;
3116
3117         if (mddev->level != 1) {
3118                 pr_warn("md/raid1:%s: raid level not set to mirroring (%d)\n",
3119                         mdname(mddev), mddev->level);
3120                 return -EIO;
3121         }
3122         if (mddev->reshape_position != MaxSector) {
3123                 pr_warn("md/raid1:%s: reshape_position set but not supported\n",
3124                         mdname(mddev));
3125                 return -EIO;
3126         }
3127         if (mddev_init_writes_pending(mddev) < 0)
3128                 return -ENOMEM;
3129         /*
3130          * copy the already verified devices into our private RAID1
3131          * bookkeeping area. [whatever we allocate in run(),
3132          * should be freed in raid1_free()]
3133          */
3134         if (mddev->private == NULL)
3135                 conf = setup_conf(mddev);
3136         else
3137                 conf = mddev->private;
3138
3139         if (IS_ERR(conf))
3140                 return PTR_ERR(conf);
3141
3142         if (mddev->queue)
3143                 blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
3144
3145         rdev_for_each(rdev, mddev) {
3146                 if (!mddev->gendisk)
3147                         continue;
3148                 disk_stack_limits(mddev->gendisk, rdev->bdev,
3149                                   rdev->data_offset << 9);
3150         }
3151
3152         mddev->degraded = 0;
3153         for (i = 0; i < conf->raid_disks; i++)
3154                 if (conf->mirrors[i].rdev == NULL ||
3155                     !test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
3156                     test_bit(Faulty, &conf->mirrors[i].rdev->flags))
3157                         mddev->degraded++;
3158         /*
3159          * RAID1 needs at least one disk in active
3160          */
3161         if (conf->raid_disks - mddev->degraded < 1) {
3162                 ret = -EINVAL;
3163                 goto abort;
3164         }
3165
3166         if (conf->raid_disks - mddev->degraded == 1)
3167                 mddev->recovery_cp = MaxSector;
3168
3169         if (mddev->recovery_cp != MaxSector)
3170                 pr_info("md/raid1:%s: not clean -- starting background reconstruction\n",
3171                         mdname(mddev));
3172         pr_info("md/raid1:%s: active with %d out of %d mirrors\n",
3173                 mdname(mddev), mddev->raid_disks - mddev->degraded,
3174                 mddev->raid_disks);
3175
3176         /*
3177          * Ok, everything is just fine now
3178          */
3179         mddev->thread = conf->thread;
3180         conf->thread = NULL;
3181         mddev->private = conf;
3182         set_bit(MD_FAILFAST_SUPPORTED, &mddev->flags);
3183
3184         md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
3185
3186         ret = md_integrity_register(mddev);
3187         if (ret) {
3188                 md_unregister_thread(&mddev->thread);
3189                 goto abort;
3190         }
3191         return 0;
3192
3193 abort:
3194         raid1_free(mddev, conf);
3195         return ret;
3196 }
3197
3198 static void raid1_free(struct mddev *mddev, void *priv)
3199 {
3200         struct r1conf *conf = priv;
3201
3202         mempool_exit(&conf->r1bio_pool);
3203         kfree(conf->mirrors);
3204         safe_put_page(conf->tmppage);
3205         kfree(conf->poolinfo);
3206         kfree(conf->nr_pending);
3207         kfree(conf->nr_waiting);
3208         kfree(conf->nr_queued);
3209         kfree(conf->barrier);
3210         bioset_exit(&conf->bio_split);
3211         kfree(conf);
3212 }
3213
3214 static int raid1_resize(struct mddev *mddev, sector_t sectors)
3215 {
3216         /* no resync is happening, and there is enough space
3217          * on all devices, so we can resize.
3218          * We need to make sure resync covers any new space.
3219          * If the array is shrinking we should possibly wait until
3220          * any io in the removed space completes, but it hardly seems
3221          * worth it.
3222          */
3223         sector_t newsize = raid1_size(mddev, sectors, 0);
3224         if (mddev->external_size &&
3225             mddev->array_sectors > newsize)
3226                 return -EINVAL;
3227         if (mddev->bitmap) {
3228                 int ret = md_bitmap_resize(mddev->bitmap, newsize, 0, 0);
3229                 if (ret)
3230                         return ret;
3231         }
3232         md_set_array_sectors(mddev, newsize);
3233         if (sectors > mddev->dev_sectors &&
3234             mddev->recovery_cp > mddev->dev_sectors) {
3235                 mddev->recovery_cp = mddev->dev_sectors;
3236                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3237         }
3238         mddev->dev_sectors = sectors;
3239         mddev->resync_max_sectors = sectors;
3240         return 0;
3241 }
3242
3243 static int raid1_reshape(struct mddev *mddev)
3244 {
3245         /* We need to:
3246          * 1/ resize the r1bio_pool
3247          * 2/ resize conf->mirrors
3248          *
3249          * We allocate a new r1bio_pool if we can.
3250          * Then raise a device barrier and wait until all IO stops.
3251          * Then resize conf->mirrors and swap in the new r1bio pool.
3252          *
3253          * At the same time, we "pack" the devices so that all the missing
3254          * devices have the higher raid_disk numbers.
3255          */
3256         mempool_t newpool, oldpool;
3257         struct pool_info *newpoolinfo;
3258         struct raid1_info *newmirrors;
3259         struct r1conf *conf = mddev->private;
3260         int cnt, raid_disks;
3261         unsigned long flags;
3262         int d, d2;
3263         int ret;
3264
3265         memset(&newpool, 0, sizeof(newpool));
3266         memset(&oldpool, 0, sizeof(oldpool));
3267
3268         /* Cannot change chunk_size, layout, or level */
3269         if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
3270             mddev->layout != mddev->new_layout ||
3271             mddev->level != mddev->new_level) {
3272                 mddev->new_chunk_sectors = mddev->chunk_sectors;
3273                 mddev->new_layout = mddev->layout;
3274                 mddev->new_level = mddev->level;
3275                 return -EINVAL;
3276         }
3277
3278         if (!mddev_is_clustered(mddev))
3279                 md_allow_write(mddev);
3280
3281         raid_disks = mddev->raid_disks + mddev->delta_disks;
3282
3283         if (raid_disks < conf->raid_disks) {
3284                 cnt=0;
3285                 for (d= 0; d < conf->raid_disks; d++)
3286                         if (conf->mirrors[d].rdev)
3287                                 cnt++;
3288                 if (cnt > raid_disks)
3289                         return -EBUSY;
3290         }
3291
3292         newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
3293         if (!newpoolinfo)
3294                 return -ENOMEM;
3295         newpoolinfo->mddev = mddev;
3296         newpoolinfo->raid_disks = raid_disks * 2;
3297
3298         ret = mempool_init(&newpool, NR_RAID_BIOS, r1bio_pool_alloc,
3299                            rbio_pool_free, newpoolinfo);
3300         if (ret) {
3301                 kfree(newpoolinfo);
3302                 return ret;
3303         }
3304         newmirrors = kzalloc(array3_size(sizeof(struct raid1_info),
3305                                          raid_disks, 2),
3306                              GFP_KERNEL);
3307         if (!newmirrors) {
3308                 kfree(newpoolinfo);
3309                 mempool_exit(&newpool);
3310                 return -ENOMEM;
3311         }
3312
3313         freeze_array(conf, 0);
3314
3315         /* ok, everything is stopped */
3316         oldpool = conf->r1bio_pool;
3317         conf->r1bio_pool = newpool;
3318
3319         for (d = d2 = 0; d < conf->raid_disks; d++) {
3320                 struct md_rdev *rdev = conf->mirrors[d].rdev;
3321                 if (rdev && rdev->raid_disk != d2) {
3322                         sysfs_unlink_rdev(mddev, rdev);
3323                         rdev->raid_disk = d2;
3324                         sysfs_unlink_rdev(mddev, rdev);
3325                         if (sysfs_link_rdev(mddev, rdev))
3326                                 pr_warn("md/raid1:%s: cannot register rd%d\n",
3327                                         mdname(mddev), rdev->raid_disk);
3328                 }
3329                 if (rdev)
3330                         newmirrors[d2++].rdev = rdev;
3331         }
3332         kfree(conf->mirrors);
3333         conf->mirrors = newmirrors;
3334         kfree(conf->poolinfo);
3335         conf->poolinfo = newpoolinfo;
3336
3337         spin_lock_irqsave(&conf->device_lock, flags);
3338         mddev->degraded += (raid_disks - conf->raid_disks);
3339         spin_unlock_irqrestore(&conf->device_lock, flags);
3340         conf->raid_disks = mddev->raid_disks = raid_disks;
3341         mddev->delta_disks = 0;
3342
3343         unfreeze_array(conf);
3344
3345         set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
3346         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3347         md_wakeup_thread(mddev->thread);
3348
3349         mempool_exit(&oldpool);
3350         return 0;
3351 }
3352
3353 static void raid1_quiesce(struct mddev *mddev, int quiesce)
3354 {
3355         struct r1conf *conf = mddev->private;
3356
3357         if (quiesce)
3358                 freeze_array(conf, 0);
3359         else
3360                 unfreeze_array(conf);
3361 }
3362
3363 static void *raid1_takeover(struct mddev *mddev)
3364 {
3365         /* raid1 can take over:
3366          *  raid5 with 2 devices, any layout or chunk size
3367          */
3368         if (mddev->level == 5 && mddev->raid_disks == 2) {
3369                 struct r1conf *conf;
3370                 mddev->new_level = 1;
3371                 mddev->new_layout = 0;
3372                 mddev->new_chunk_sectors = 0;
3373                 conf = setup_conf(mddev);
3374                 if (!IS_ERR(conf)) {
3375                         /* Array must appear to be quiesced */
3376                         conf->array_frozen = 1;
3377                         mddev_clear_unsupported_flags(mddev,
3378                                 UNSUPPORTED_MDDEV_FLAGS);
3379                 }
3380                 return conf;
3381         }
3382         return ERR_PTR(-EINVAL);
3383 }
3384
3385 static struct md_personality raid1_personality =
3386 {
3387         .name           = "raid1",
3388         .level          = 1,
3389         .owner          = THIS_MODULE,
3390         .make_request   = raid1_make_request,
3391         .run            = raid1_run,
3392         .free           = raid1_free,
3393         .status         = raid1_status,
3394         .error_handler  = raid1_error,
3395         .hot_add_disk   = raid1_add_disk,
3396         .hot_remove_disk= raid1_remove_disk,
3397         .spare_active   = raid1_spare_active,
3398         .sync_request   = raid1_sync_request,
3399         .resize         = raid1_resize,
3400         .size           = raid1_size,
3401         .check_reshape  = raid1_reshape,
3402         .quiesce        = raid1_quiesce,
3403         .takeover       = raid1_takeover,
3404 };
3405
3406 static int __init raid_init(void)
3407 {
3408         return register_md_personality(&raid1_personality);
3409 }
3410
3411 static void raid_exit(void)
3412 {
3413         unregister_md_personality(&raid1_personality);
3414 }
3415
3416 module_init(raid_init);
3417 module_exit(raid_exit);
3418 MODULE_LICENSE("GPL");
3419 MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
3420 MODULE_ALIAS("md-personality-3"); /* RAID1 */
3421 MODULE_ALIAS("md-raid1");
3422 MODULE_ALIAS("md-level-1");