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(gfp_flags, RESYNC_PAGES);
 169                 if (!bio)
 170                         goto out_free_bio;
 171                 r1_bio->bios[j] = bio;
 172         }
 173         /*
 174          * Allocate RESYNC_PAGES data pages and attach them to
 175          * the first bio.
 176          * If this is a user-requested check/repair, allocate
 177          * RESYNC_PAGES for each bio.
 178          */
 179         if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
 180                 need_pages = pi->raid_disks;
 181         else
 182                 need_pages = 1;
 183         for (j = 0; j < pi->raid_disks; j++) {
 184                 struct resync_pages *rp = &rps[j];
 185
 186                 bio = r1_bio->bios[j];
 187
 188                 if (j < need_pages) {
 189                         if (resync_alloc_pages(rp, gfp_flags))
 190                                 goto out_free_pages;
 191                 } else {
 192                         memcpy(rp, &rps[0], sizeof(*rp));
 193                         resync_get_all_pages(rp);
 194                 }
 195
 196                 rp->raid_bio = r1_bio;
 197                 bio->bi_private = rp;
 198         }
 199
 200         r1_bio->master_bio = NULL;
 201
 202         return r1_bio;
 203
 204 out_free_pages:
 205         while (--j >= 0)
 206                 resync_free_pages(&rps[j]);
 207
 208 out_free_bio:
 209         while (++j < pi->raid_disks)
 210                 bio_put(r1_bio->bios[j]);
 211         kfree(rps);
 212
 213 out_free_r1bio:
 214         rbio_pool_free(r1_bio, data);
 215         return NULL;
 216 }
 217
 218 static void r1buf_pool_free(void *__r1_bio, void *data)
 219 {
 220         struct pool_info *pi = data;
 221         int i;
 222         struct r1bio *r1bio = __r1_bio;
 223         struct resync_pages *rp = NULL;
 224
 225         for (i = pi->raid_disks; i--; ) {
 226                 rp = get_resync_pages(r1bio->bios[i]);
 227                 resync_free_pages(rp);
 228                 bio_put(r1bio->bios[i]);
 229         }
 230
 231         /* resync pages array stored in the 1st bio's .bi_private */
 232         kfree(rp);
 233
 234         rbio_pool_free(r1bio, data);
 235 }
 236
 237 static void put_all_bios(struct r1conf *conf, struct r1bio *r1_bio)
 238 {
 239         int i;
 240
 241         for (i = 0; i < conf->raid_disks * 2; i++) {
 242                 struct bio **bio = r1_bio->bios + i;
 243                 if (!BIO_SPECIAL(*bio))
 244                         bio_put(*bio);
 245                 *bio = NULL;
 246         }
 247 }
 248
 249 static void free_r1bio(struct r1bio *r1_bio)
 250 {
 251         struct r1conf *conf = r1_bio->mddev->private;
 252
 253         put_all_bios(conf, r1_bio);
 254         mempool_free(r1_bio, &conf->r1bio_pool);
 255 }
 256
 257 static void put_buf(struct r1bio *r1_bio)
 258 {
 259         struct r1conf *conf = r1_bio->mddev->private;
 260         sector_t sect = r1_bio->sector;
 261         int i;
 262
 263         for (i = 0; i < conf->raid_disks * 2; i++) {
 264                 struct bio *bio = r1_bio->bios[i];
 265                 if (bio->bi_end_io)
 266                         rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
 267         }
 268
 269         mempool_free(r1_bio, &conf->r1buf_pool);
 270
 271         lower_barrier(conf, sect);
 272 }
 273
 274 static void reschedule_retry(struct r1bio *r1_bio)
 275 {
 276         unsigned long flags;
 277         struct mddev *mddev = r1_bio->mddev;
 278         struct r1conf *conf = mddev->private;
 279         int idx;
 280
 281         idx = sector_to_idx(r1_bio->sector);
 282         spin_lock_irqsave(&conf->device_lock, flags);
 283         list_add(&r1_bio->retry_list, &conf->retry_list);
 284         atomic_inc(&conf->nr_queued[idx]);
 285         spin_unlock_irqrestore(&conf->device_lock, flags);
 286
 287         wake_up(&conf->wait_barrier);
 288         md_wakeup_thread(mddev->thread);
 289 }
 290
 291 /*
 292  * raid_end_bio_io() is called when we have finished servicing a mirrored
 293  * operation and are ready to return a success/failure code to the buffer
 294  * cache layer.
 295  */
 296 static void call_bio_endio(struct r1bio *r1_bio)
 297 {
 298         struct bio *bio = r1_bio->master_bio;
 299
 300         if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
 301                 bio->bi_status = BLK_STS_IOERR;
 302
 303         if (blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
 304                 bio_end_io_acct(bio, r1_bio->start_time);
 305         bio_endio(bio);
 306 }
 307
 308 static void raid_end_bio_io(struct r1bio *r1_bio)
 309 {
 310         struct bio *bio = r1_bio->master_bio;
 311         struct r1conf *conf = r1_bio->mddev->private;
 312
 313         /* if nobody has done the final endio yet, do it now */
 314         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 315                 pr_debug("raid1: sync end %s on sectors %llu-%llu\n",
 316                          (bio_data_dir(bio) == WRITE) ? "write" : "read",
 317                          (unsigned long long) bio->bi_iter.bi_sector,
 318                          (unsigned long long) bio_end_sector(bio) - 1);
 319
 320                 call_bio_endio(r1_bio);
 321         }
 322         /*
 323          * Wake up any possible resync thread that waits for the device
 324          * to go idle.  All I/Os, even write-behind writes, are done.
 325          */
 326         allow_barrier(conf, r1_bio->sector);
 327
 328         free_r1bio(r1_bio);
 329 }
 330
 331 /*
 332  * Update disk head position estimator based on IRQ completion info.
 333  */
 334 static inline void update_head_pos(int disk, struct r1bio *r1_bio)
 335 {
 336         struct r1conf *conf = r1_bio->mddev->private;
 337
 338         conf->mirrors[disk].head_position =
 339                 r1_bio->sector + (r1_bio->sectors);
 340 }
 341
 342 /*
 343  * Find the disk number which triggered given bio
 344  */
 345 static int find_bio_disk(struct r1bio *r1_bio, struct bio *bio)
 346 {
 347         int mirror;
 348         struct r1conf *conf = r1_bio->mddev->private;
 349         int raid_disks = conf->raid_disks;
 350
 351         for (mirror = 0; mirror < raid_disks * 2; mirror++)
 352                 if (r1_bio->bios[mirror] == bio)
 353                         break;
 354
 355         BUG_ON(mirror == raid_disks * 2);
 356         update_head_pos(mirror, r1_bio);
 357
 358         return mirror;
 359 }
 360
 361 static void raid1_end_read_request(struct bio *bio)
 362 {
 363         int uptodate = !bio->bi_status;
 364         struct r1bio *r1_bio = bio->bi_private;
 365         struct r1conf *conf = r1_bio->mddev->private;
 366         struct md_rdev *rdev = conf->mirrors[r1_bio->read_disk].rdev;
 367
 368         /*
 369          * this branch is our 'one mirror IO has finished' event handler:
 370          */
 371         update_head_pos(r1_bio->read_disk, r1_bio);
 372
 373         if (uptodate)
 374                 set_bit(R1BIO_Uptodate, &r1_bio->state);
 375         else if (test_bit(FailFast, &rdev->flags) &&
 376                  test_bit(R1BIO_FailFast, &r1_bio->state))
 377                 /* This was a fail-fast read so we definitely
 378                  * want to retry */
 379                 ;
 380         else {
 381                 /* If all other devices have failed, we want to return
 382                  * the error upwards rather than fail the last device.
 383                  * Here we redefine "uptodate" to mean "Don't want to retry"
 384                  */
 385                 unsigned long flags;
 386                 spin_lock_irqsave(&conf->device_lock, flags);
 387                 if (r1_bio->mddev->degraded == conf->raid_disks ||
 388                     (r1_bio->mddev->degraded == conf->raid_disks-1 &&
 389                      test_bit(In_sync, &rdev->flags)))
 390                         uptodate = 1;
 391                 spin_unlock_irqrestore(&conf->device_lock, flags);
 392         }
 393
 394         if (uptodate) {
 395                 raid_end_bio_io(r1_bio);
 396                 rdev_dec_pending(rdev, conf->mddev);
 397         } else {
 398                 /*
 399                  * oops, read error:
 400                  */
 401                 char b[BDEVNAME_SIZE];
 402                 pr_err_ratelimited("md/raid1:%s: %s: rescheduling sector %llu\n",
 403                                    mdname(conf->mddev),
 404                                    bdevname(rdev->bdev, b),
 405                                    (unsigned long long)r1_bio->sector);
 406                 set_bit(R1BIO_ReadError, &r1_bio->state);
 407                 reschedule_retry(r1_bio);
 408                 /* don't drop the reference on read_disk yet */
 409         }
 410 }
 411
 412 static void close_write(struct r1bio *r1_bio)
 413 {
 414         /* it really is the end of this request */
 415         if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
 416                 bio_free_pages(r1_bio->behind_master_bio);
 417                 bio_put(r1_bio->behind_master_bio);
 418                 r1_bio->behind_master_bio = NULL;
 419         }
 420         /* clear the bitmap if all writes complete successfully */
 421         md_bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
 422                            r1_bio->sectors,
 423                            !test_bit(R1BIO_Degraded, &r1_bio->state),
 424                            test_bit(R1BIO_BehindIO, &r1_bio->state));
 425         md_write_end(r1_bio->mddev);
 426 }
 427
 428 static void r1_bio_write_done(struct r1bio *r1_bio)
 429 {
 430         if (!atomic_dec_and_test(&r1_bio->remaining))
 431                 return;
 432
 433         if (test_bit(R1BIO_WriteError, &r1_bio->state))
 434                 reschedule_retry(r1_bio);
 435         else {
 436                 close_write(r1_bio);
 437                 if (test_bit(R1BIO_MadeGood, &r1_bio->state))
 438                         reschedule_retry(r1_bio);
 439                 else
 440                         raid_end_bio_io(r1_bio);
 441         }
 442 }
 443
 444 static void raid1_end_write_request(struct bio *bio)
 445 {
 446         struct r1bio *r1_bio = bio->bi_private;
 447         int behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
 448         struct r1conf *conf = r1_bio->mddev->private;
 449         struct bio *to_put = NULL;
 450         int mirror = find_bio_disk(r1_bio, bio);
 451         struct md_rdev *rdev = conf->mirrors[mirror].rdev;
 452         bool discard_error;
 453         sector_t lo = r1_bio->sector;
 454         sector_t hi = r1_bio->sector + r1_bio->sectors;
 455
 456         discard_error = bio->bi_status && bio_op(bio) == REQ_OP_DISCARD;
 457
 458         /*
 459          * 'one mirror IO has finished' event handler:
 460          */
 461         if (bio->bi_status && !discard_error) {
 462                 set_bit(WriteErrorSeen, &rdev->flags);
 463                 if (!test_and_set_bit(WantReplacement, &rdev->flags))
 464                         set_bit(MD_RECOVERY_NEEDED, &
 465                                 conf->mddev->recovery);
 466
 467                 if (test_bit(FailFast, &rdev->flags) &&
 468                     (bio->bi_opf & MD_FAILFAST) &&
 469                     /* We never try FailFast to WriteMostly devices */
 470                     !test_bit(WriteMostly, &rdev->flags)) {
 471                         md_error(r1_bio->mddev, rdev);
 472                 }
 473
 474                 /*
 475                  * When the device is faulty, it is not necessary to
 476                  * handle write error.
 477                  */
 478                 if (!test_bit(Faulty, &rdev->flags))
 479                         set_bit(R1BIO_WriteError, &r1_bio->state);
 480                 else {
 481                         /* Fail the request */
 482                         set_bit(R1BIO_Degraded, &r1_bio->state);
 483                         /* Finished with this branch */
 484                         r1_bio->bios[mirror] = NULL;
 485                         to_put = bio;
 486                 }
 487         } else {
 488                 /*
 489                  * Set R1BIO_Uptodate in our master bio, so that we
 490                  * will return a good error code for to the higher
 491                  * levels even if IO on some other mirrored buffer
 492                  * fails.
 493                  *
 494                  * The 'master' represents the composite IO operation
 495                  * to user-side. So if something waits for IO, then it
 496                  * will wait for the 'master' bio.
 497                  */
 498                 sector_t first_bad;
 499                 int bad_sectors;
 500
 501                 r1_bio->bios[mirror] = NULL;
 502                 to_put = bio;
 503                 /*
 504                  * Do not set R1BIO_Uptodate if the current device is
 505                  * rebuilding or Faulty. This is because we cannot use
 506                  * such device for properly reading the data back (we could
 507                  * potentially use it, if the current write would have felt
 508                  * before rdev->recovery_offset, but for simplicity we don't
 509                  * check this here.
 510                  */
 511                 if (test_bit(In_sync, &rdev->flags) &&
 512                     !test_bit(Faulty, &rdev->flags))
 513                         set_bit(R1BIO_Uptodate, &r1_bio->state);
 514
 515                 /* Maybe we can clear some bad blocks. */
 516                 if (is_badblock(rdev, r1_bio->sector, r1_bio->sectors,
 517                                 &first_bad, &bad_sectors) && !discard_error) {
 518                         r1_bio->bios[mirror] = IO_MADE_GOOD;
 519                         set_bit(R1BIO_MadeGood, &r1_bio->state);
 520                 }
 521         }
 522
 523         if (behind) {
 524                 if (test_bit(CollisionCheck, &rdev->flags))
 525                         remove_serial(rdev, lo, hi);
 526                 if (test_bit(WriteMostly, &rdev->flags))
 527                         atomic_dec(&r1_bio->behind_remaining);
 528
 529                 /*
 530                  * In behind mode, we ACK the master bio once the I/O
 531                  * has safely reached all non-writemostly
 532                  * disks. Setting the Returned bit ensures that this
 533                  * gets done only once -- we don't ever want to return
 534                  * -EIO here, instead we'll wait
 535                  */
 536                 if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
 537                     test_bit(R1BIO_Uptodate, &r1_bio->state)) {
 538                         /* Maybe we can return now */
 539                         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 540                                 struct bio *mbio = r1_bio->master_bio;
 541                                 pr_debug("raid1: behind end write sectors"
 542                                          " %llu-%llu\n",
 543                                          (unsigned long long) mbio->bi_iter.bi_sector,
 544                                          (unsigned long long) bio_end_sector(mbio) - 1);
 545                                 call_bio_endio(r1_bio);
 546                         }
 547                 }
 548         } else if (rdev->mddev->serialize_policy)
 549                 remove_serial(rdev, lo, hi);
 550         if (r1_bio->bios[mirror] == NULL)
 551                 rdev_dec_pending(rdev, conf->mddev);
 552
 553         /*
 554          * Let's see if all mirrored write operations have finished
 555          * already.
 556          */
 557         r1_bio_write_done(r1_bio);
 558
 559         if (to_put)
 560                 bio_put(to_put);
 561 }
 562
 563 static sector_t align_to_barrier_unit_end(sector_t start_sector,
 564                                           sector_t sectors)
 565 {
 566         sector_t len;
 567
 568         WARN_ON(sectors == 0);
 569         /*
 570          * len is the number of sectors from start_sector to end of the
 571          * barrier unit which start_sector belongs to.
 572          */
 573         len = round_up(start_sector + 1, BARRIER_UNIT_SECTOR_SIZE) -
 574               start_sector;
 575
 576         if (len > sectors)
 577                 len = sectors;
 578
 579         return len;
 580 }
 581
 582 /*
 583  * This routine returns the disk from which the requested read should
 584  * be done. There is a per-array 'next expected sequential IO' sector
 585  * number - if this matches on the next IO then we use the last disk.
 586  * There is also a per-disk 'last know head position' sector that is
 587  * maintained from IRQ contexts, both the normal and the resync IO
 588  * completion handlers update this position correctly. If there is no
 589  * perfect sequential match then we pick the disk whose head is closest.
 590  *
 591  * If there are 2 mirrors in the same 2 devices, performance degrades
 592  * because position is mirror, not device based.
 593  *
 594  * The rdev for the device selected will have nr_pending incremented.
 595  */
 596 static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sectors)
 597 {
 598         const sector_t this_sector = r1_bio->sector;
 599         int sectors;
 600         int best_good_sectors;
 601         int best_disk, best_dist_disk, best_pending_disk;
 602         int has_nonrot_disk;
 603         int disk;
 604         sector_t best_dist;
 605         unsigned int min_pending;
 606         struct md_rdev *rdev;
 607         int choose_first;
 608         int choose_next_idle;
 609
 610         rcu_read_lock();
 611         /*
 612          * Check if we can balance. We can balance on the whole
 613          * device if no resync is going on, or below the resync window.
 614          * We take the first readable disk when above the resync window.
 615          */
 616  retry:
 617         sectors = r1_bio->sectors;
 618         best_disk = -1;
 619         best_dist_disk = -1;
 620         best_dist = MaxSector;
 621         best_pending_disk = -1;
 622         min_pending = UINT_MAX;
 623         best_good_sectors = 0;
 624         has_nonrot_disk = 0;
 625         choose_next_idle = 0;
 626         clear_bit(R1BIO_FailFast, &r1_bio->state);
 627
 628         if ((conf->mddev->recovery_cp < this_sector + sectors) ||
 629             (mddev_is_clustered(conf->mddev) &&
 630             md_cluster_ops->area_resyncing(conf->mddev, READ, this_sector,
 631                     this_sector + sectors)))
 632                 choose_first = 1;
 633         else
 634                 choose_first = 0;
 635
 636         for (disk = 0 ; disk < conf->raid_disks * 2 ; disk++) {
 637                 sector_t dist;
 638                 sector_t first_bad;
 639                 int bad_sectors;
 640                 unsigned int pending;
 641                 bool nonrot;
 642
 643                 rdev = rcu_dereference(conf->mirrors[disk].rdev);
 644                 if (r1_bio->bios[disk] == IO_BLOCKED
 645                     || rdev == NULL
 646                     || test_bit(Faulty, &rdev->flags))
 647                         continue;
 648                 if (!test_bit(In_sync, &rdev->flags) &&
 649                     rdev->recovery_offset < this_sector + sectors)
 650                         continue;
 651                 if (test_bit(WriteMostly, &rdev->flags)) {
 652                         /* Don't balance among write-mostly, just
 653                          * use the first as a last resort */
 654                         if (best_dist_disk < 0) {
 655                                 if (is_badblock(rdev, this_sector, sectors,
 656                                                 &first_bad, &bad_sectors)) {
 657                                         if (first_bad <= this_sector)
 658                                                 /* Cannot use this */
 659                                                 continue;
 660                                         best_good_sectors = first_bad - this_sector;
 661                                 } else
 662                                         best_good_sectors = sectors;
 663                                 best_dist_disk = disk;
 664                                 best_pending_disk = disk;
 665                         }
 666                         continue;
 667                 }
 668                 /* This is a reasonable device to use.  It might
 669                  * even be best.
 670                  */
 671                 if (is_badblock(rdev, this_sector, sectors,
 672                                 &first_bad, &bad_sectors)) {
 673                         if (best_dist < MaxSector)
 674                                 /* already have a better device */
 675                                 continue;
 676                         if (first_bad <= this_sector) {
 677                                 /* cannot read here. If this is the 'primary'
 678                                  * device, then we must not read beyond
 679                                  * bad_sectors from another device..
 680                                  */
 681                                 bad_sectors -= (this_sector - first_bad);
 682                                 if (choose_first && sectors > bad_sectors)
 683                                         sectors = bad_sectors;
 684                                 if (best_good_sectors > sectors)
 685                                         best_good_sectors = sectors;
 686
 687                         } else {
 688                                 sector_t good_sectors = first_bad - this_sector;
 689                                 if (good_sectors > best_good_sectors) {
 690                                         best_good_sectors = good_sectors;
 691                                         best_disk = disk;
 692                                 }
 693                                 if (choose_first)
 694                                         break;
 695                         }
 696                         continue;
 697                 } else {
 698                         if ((sectors > best_good_sectors) && (best_disk >= 0))
 699                                 best_disk = -1;
 700                         best_good_sectors = sectors;
 701                 }
 702
 703                 if (best_disk >= 0)
 704                         /* At least two disks to choose from so failfast is OK */
 705                         set_bit(R1BIO_FailFast, &r1_bio->state);
 706
 707                 nonrot = blk_queue_nonrot(bdev_get_queue(rdev->bdev));
 708                 has_nonrot_disk |= nonrot;
 709                 pending = atomic_read(&rdev->nr_pending);
 710                 dist = abs(this_sector - conf->mirrors[disk].head_position);
 711                 if (choose_first) {
 712                         best_disk = disk;
 713                         break;
 714                 }
 715                 /* Don't change to another disk for sequential reads */
 716                 if (conf->mirrors[disk].next_seq_sect == this_sector
 717                     || dist == 0) {
 718                         int opt_iosize = bdev_io_opt(rdev->bdev) >> 9;
 719                         struct raid1_info *mirror = &conf->mirrors[disk];
 720
 721                         best_disk = disk;
 722                         /*
 723                          * If buffered sequential IO size exceeds optimal
 724                          * iosize, check if there is idle disk. If yes, choose
 725                          * the idle disk. read_balance could already choose an
 726                          * idle disk before noticing it's a sequential IO in
 727                          * this disk. This doesn't matter because this disk
 728                          * will idle, next time it will be utilized after the
 729                          * first disk has IO size exceeds optimal iosize. In
 730                          * this way, iosize of the first disk will be optimal
 731                          * iosize at least. iosize of the second disk might be
 732                          * small, but not a big deal since when the second disk
 733                          * starts IO, the first disk is likely still busy.
 734                          */
 735                         if (nonrot && opt_iosize > 0 &&
 736                             mirror->seq_start != MaxSector &&
 737                             mirror->next_seq_sect > opt_iosize &&
 738                             mirror->next_seq_sect - opt_iosize >=
 739                             mirror->seq_start) {
 740                                 choose_next_idle = 1;
 741                                 continue;
 742                         }
 743                         break;
 744                 }
 745
 746                 if (choose_next_idle)
 747                         continue;
 748
 749                 if (min_pending > pending) {
 750                         min_pending = pending;
 751                         best_pending_disk = disk;
 752                 }
 753
 754                 if (dist < best_dist) {
 755                         best_dist = dist;
 756                         best_dist_disk = disk;
 757                 }
 758         }
 759
 760         /*
 761          * If all disks are rotational, choose the closest disk. If any disk is
 762          * non-rotational, choose the disk with less pending request even the
 763          * disk is rotational, which might/might not be optimal for raids with
 764          * mixed ratation/non-rotational disks depending on workload.
 765          */
 766         if (best_disk == -1) {
 767                 if (has_nonrot_disk || min_pending == 0)
 768                         best_disk = best_pending_disk;
 769                 else
 770                         best_disk = best_dist_disk;
 771         }
 772
 773         if (best_disk >= 0) {
 774                 rdev = rcu_dereference(conf->mirrors[best_disk].rdev);
 775                 if (!rdev)
 776                         goto retry;
 777                 atomic_inc(&rdev->nr_pending);
 778                 sectors = best_good_sectors;
 779
 780                 if (conf->mirrors[best_disk].next_seq_sect != this_sector)
 781                         conf->mirrors[best_disk].seq_start = this_sector;
 782
 783                 conf->mirrors[best_disk].next_seq_sect = this_sector + sectors;
 784         }
 785         rcu_read_unlock();
 786         *max_sectors = sectors;
 787
 788         return best_disk;
 789 }
 790
 791 static void flush_bio_list(struct r1conf *conf, struct bio *bio)
 792 {
 793         /* flush any pending bitmap writes to disk before proceeding w/ I/O */
 794         md_bitmap_unplug(conf->mddev->bitmap);
 795         wake_up(&conf->wait_barrier);
 796
 797         while (bio) { /* submit pending writes */
 798                 struct bio *next = bio->bi_next;
 799                 struct md_rdev *rdev = (void *)bio->bi_bdev;
 800                 bio->bi_next = NULL;
 801                 bio_set_dev(bio, rdev->bdev);
 802                 if (test_bit(Faulty, &rdev->flags)) {
 803                         bio_io_error(bio);
 804                 } else if (unlikely((bio_op(bio) == REQ_OP_DISCARD) &&
 805                                     !blk_queue_discard(bio->bi_bdev->bd_disk->queue)))
 806                         /* Just ignore it */
 807                         bio_endio(bio);
 808                 else
 809                         submit_bio_noacct(bio);
 810                 bio = next;
 811                 cond_resched();
 812         }
 813 }
 814
 815 static void flush_pending_writes(struct r1conf *conf)
 816 {
 817         /* Any writes that have been queued but are awaiting
 818          * bitmap updates get flushed here.
 819          */
 820         spin_lock_irq(&conf->device_lock);
 821
 822         if (conf->pending_bio_list.head) {
 823                 struct blk_plug plug;
 824                 struct bio *bio;
 825
 826                 bio = bio_list_get(&conf->pending_bio_list);
 827                 spin_unlock_irq(&conf->device_lock);
 828
 829                 /*
 830                  * As this is called in a wait_event() loop (see freeze_array),
 831                  * current->state might be TASK_UNINTERRUPTIBLE which will
 832                  * cause a warning when we prepare to wait again.  As it is
 833                  * rare that this path is taken, it is perfectly safe to force
 834                  * us to go around the wait_event() loop again, so the warning
 835                  * is a false-positive.  Silence the warning by resetting
 836                  * thread state
 837                  */
 838                 __set_current_state(TASK_RUNNING);
 839                 blk_start_plug(&plug);
 840                 flush_bio_list(conf, bio);
 841                 blk_finish_plug(&plug);
 842         } else
 843                 spin_unlock_irq(&conf->device_lock);
 844 }
 845
 846 /* Barriers....
 847  * Sometimes we need to suspend IO while we do something else,
 848  * either some resync/recovery, or reconfigure the array.
 849  * To do this we raise a 'barrier'.
 850  * The 'barrier' is a counter that can be raised multiple times
 851  * to count how many activities are happening which preclude
 852  * normal IO.
 853  * We can only raise the barrier if there is no pending IO.
 854  * i.e. if nr_pending == 0.
 855  * We choose only to raise the barrier if no-one is waiting for the
 856  * barrier to go down.  This means that as soon as an IO request
 857  * is ready, no other operations which require a barrier will start
 858  * until the IO request has had a chance.
 859  *
 860  * So: regular IO calls 'wait_barrier'.  When that returns there
 861  *    is no backgroup IO happening,  It must arrange to call
 862  *    allow_barrier when it has finished its IO.
 863  * backgroup IO calls must call raise_barrier.  Once that returns
 864  *    there is no normal IO happeing.  It must arrange to call
 865  *    lower_barrier when the particular background IO completes.
 866  *
 867  * If resync/recovery is interrupted, returns -EINTR;
 868  * Otherwise, returns 0.
 869  */
 870 static int raise_barrier(struct r1conf *conf, sector_t sector_nr)
 871 {
 872         int idx = sector_to_idx(sector_nr);
 873
 874         spin_lock_irq(&conf->resync_lock);
 875
 876         /* Wait until no block IO is waiting */
 877         wait_event_lock_irq(conf->wait_barrier,
 878                             !atomic_read(&conf->nr_waiting[idx]),
 879                             conf->resync_lock);
 880
 881         /* block any new IO from starting */
 882         atomic_inc(&conf->barrier[idx]);
 883         /*
 884          * In raise_barrier() we firstly increase conf->barrier[idx] then
 885          * check conf->nr_pending[idx]. In _wait_barrier() we firstly
 886          * increase conf->nr_pending[idx] then check conf->barrier[idx].
 887          * A memory barrier here to make sure conf->nr_pending[idx] won't
 888          * be fetched before conf->barrier[idx] is increased. Otherwise
 889          * there will be a race between raise_barrier() and _wait_barrier().
 890          */
 891         smp_mb__after_atomic();
 892
 893         /* For these conditions we must wait:
 894          * A: while the array is in frozen state
 895          * B: while conf->nr_pending[idx] is not 0, meaning regular I/O
 896          *    existing in corresponding I/O barrier bucket.
 897          * C: while conf->barrier[idx] >= RESYNC_DEPTH, meaning reaches
 898          *    max resync count which allowed on current I/O barrier bucket.
 899          */
 900         wait_event_lock_irq(conf->wait_barrier,
 901                             (!conf->array_frozen &&
 902                              !atomic_read(&conf->nr_pending[idx]) &&
 903                              atomic_read(&conf->barrier[idx]) < RESYNC_DEPTH) ||
 904                                 test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery),
 905                             conf->resync_lock);
 906
 907         if (test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
 908                 atomic_dec(&conf->barrier[idx]);
 909                 spin_unlock_irq(&conf->resync_lock);
 910                 wake_up(&conf->wait_barrier);
 911                 return -EINTR;
 912         }
 913
 914         atomic_inc(&conf->nr_sync_pending);
 915         spin_unlock_irq(&conf->resync_lock);
 916
 917         return 0;
 918 }
 919
 920 static void lower_barrier(struct r1conf *conf, sector_t sector_nr)
 921 {
 922         int idx = sector_to_idx(sector_nr);
 923
 924         BUG_ON(atomic_read(&conf->barrier[idx]) <= 0);
 925
 926         atomic_dec(&conf->barrier[idx]);
 927         atomic_dec(&conf->nr_sync_pending);
 928         wake_up(&conf->wait_barrier);
 929 }
 930
 931 static bool _wait_barrier(struct r1conf *conf, int idx, bool nowait)
 932 {
 933         bool ret = true;
 934
 935         /*
 936          * We need to increase conf->nr_pending[idx] very early here,
 937          * then raise_barrier() can be blocked when it waits for
 938          * conf->nr_pending[idx] to be 0. Then we can avoid holding
 939          * conf->resync_lock when there is no barrier raised in same
 940          * barrier unit bucket. Also if the array is frozen, I/O
 941          * should be blocked until array is unfrozen.
 942          */
 943         atomic_inc(&conf->nr_pending[idx]);
 944         /*
 945          * In _wait_barrier() we firstly increase conf->nr_pending[idx], then
 946          * check conf->barrier[idx]. In raise_barrier() we firstly increase
 947          * conf->barrier[idx], then check conf->nr_pending[idx]. A memory
 948          * barrier is necessary here to make sure conf->barrier[idx] won't be
 949          * fetched before conf->nr_pending[idx] is increased. Otherwise there
 950          * will be a race between _wait_barrier() and raise_barrier().
 951          */
 952         smp_mb__after_atomic();
 953
 954         /*
 955          * Don't worry about checking two atomic_t variables at same time
 956          * here. If during we check conf->barrier[idx], the array is
 957          * frozen (conf->array_frozen is 1), and chonf->barrier[idx] is
 958          * 0, it is safe to return and make the I/O continue. Because the
 959          * array is frozen, all I/O returned here will eventually complete
 960          * or be queued, no race will happen. See code comment in
 961          * frozen_array().
 962          */
 963         if (!READ_ONCE(conf->array_frozen) &&
 964             !atomic_read(&conf->barrier[idx]))
 965                 return ret;
 966
 967         /*
 968          * After holding conf->resync_lock, conf->nr_pending[idx]
 969          * should be decreased before waiting for barrier to drop.
 970          * Otherwise, we may encounter a race condition because
 971          * raise_barrer() might be waiting for conf->nr_pending[idx]
 972          * to be 0 at same time.
 973          */
 974         spin_lock_irq(&conf->resync_lock);
 975         atomic_inc(&conf->nr_waiting[idx]);
 976         atomic_dec(&conf->nr_pending[idx]);
 977         /*
 978          * In case freeze_array() is waiting for
 979          * get_unqueued_pending() == extra
 980          */
 981         wake_up(&conf->wait_barrier);
 982         /* Wait for the barrier in same barrier unit bucket to drop. */
 983
 984         /* Return false when nowait flag is set */
 985         if (nowait) {
 986                 ret = false;
 987         } else {
 988                 wait_event_lock_irq(conf->wait_barrier,
 989                                 !conf->array_frozen &&
 990                                 !atomic_read(&conf->barrier[idx]),
 991                                 conf->resync_lock);
 992                 atomic_inc(&conf->nr_pending[idx]);
 993         }
 994
 995         atomic_dec(&conf->nr_waiting[idx]);
 996         spin_unlock_irq(&conf->resync_lock);
 997         return ret;
 998 }
 999
1000 static bool wait_read_barrier(struct r1conf *conf, sector_t sector_nr, bool nowait)
1001 {
1002         int idx = sector_to_idx(sector_nr);
1003         bool ret = true;
1004
1005         /*
1006          * Very similar to _wait_barrier(). The difference is, for read
1007          * I/O we don't need wait for sync I/O, but if the whole array
1008          * is frozen, the read I/O still has to wait until the array is
1009          * unfrozen. Since there is no ordering requirement with
1010          * conf->barrier[idx] here, memory barrier is unnecessary as well.
1011          */
1012         atomic_inc(&conf->nr_pending[idx]);
1013
1014         if (!READ_ONCE(conf->array_frozen))
1015                 return ret;
1016
1017         spin_lock_irq(&conf->resync_lock);
1018         atomic_inc(&conf->nr_waiting[idx]);
1019         atomic_dec(&conf->nr_pending[idx]);
1020         /*
1021          * In case freeze_array() is waiting for
1022          * get_unqueued_pending() == extra
1023          */
1024         wake_up(&conf->wait_barrier);
1025         /* Wait for array to be unfrozen */
1026
1027         /* Return false when nowait flag is set */
1028         if (nowait) {
1029                 /* Return false when nowait flag is set */
1030                 ret = false;
1031         } else {
1032                 wait_event_lock_irq(conf->wait_barrier,
1033                                 !conf->array_frozen,
1034                                 conf->resync_lock);
1035                 atomic_inc(&conf->nr_pending[idx]);
1036         }
1037
1038         atomic_dec(&conf->nr_waiting[idx]);
1039         spin_unlock_irq(&conf->resync_lock);
1040         return ret;
1041 }
1042
1043 static bool wait_barrier(struct r1conf *conf, sector_t sector_nr, bool nowait)
1044 {
1045         int idx = sector_to_idx(sector_nr);
1046
1047         return _wait_barrier(conf, idx, nowait);
1048 }
1049
1050 static void _allow_barrier(struct r1conf *conf, int idx)
1051 {
1052         atomic_dec(&conf->nr_pending[idx]);
1053         wake_up(&conf->wait_barrier);
1054 }
1055
1056 static void allow_barrier(struct r1conf *conf, sector_t sector_nr)
1057 {
1058         int idx = sector_to_idx(sector_nr);
1059
1060         _allow_barrier(conf, idx);
1061 }
1062
1063 /* conf->resync_lock should be held */
1064 static int get_unqueued_pending(struct r1conf *conf)
1065 {
1066         int idx, ret;
1067
1068         ret = atomic_read(&conf->nr_sync_pending);
1069         for (idx = 0; idx < BARRIER_BUCKETS_NR; idx++)
1070                 ret += atomic_read(&conf->nr_pending[idx]) -
1071                         atomic_read(&conf->nr_queued[idx]);
1072
1073         return ret;
1074 }
1075
1076 static void freeze_array(struct r1conf *conf, int extra)
1077 {
1078         /* Stop sync I/O and normal I/O and wait for everything to
1079          * go quiet.
1080          * This is called in two situations:
1081          * 1) management command handlers (reshape, remove disk, quiesce).
1082          * 2) one normal I/O request failed.
1083
1084          * After array_frozen is set to 1, new sync IO will be blocked at
1085          * raise_barrier(), and new normal I/O will blocked at _wait_barrier()
1086          * or wait_read_barrier(). The flying I/Os will either complete or be
1087          * queued. When everything goes quite, there are only queued I/Os left.
1088
1089          * Every flying I/O contributes to a conf->nr_pending[idx], idx is the
1090          * barrier bucket index which this I/O request hits. When all sync and
1091          * normal I/O are queued, sum of all conf->nr_pending[] will match sum
1092          * of all conf->nr_queued[]. But normal I/O failure is an exception,
1093          * in handle_read_error(), we may call freeze_array() before trying to
1094          * fix the read error. In this case, the error read I/O is not queued,
1095          * so get_unqueued_pending() == 1.
1096          *
1097          * Therefore before this function returns, we need to wait until
1098          * get_unqueued_pendings(conf) gets equal to extra. For
1099          * normal I/O context, extra is 1, in rested situations extra is 0.
1100          */
1101         spin_lock_irq(&conf->resync_lock);
1102         conf->array_frozen = 1;
1103         raid1_log(conf->mddev, "wait freeze");
1104         wait_event_lock_irq_cmd(
1105                 conf->wait_barrier,
1106                 get_unqueued_pending(conf) == extra,
1107                 conf->resync_lock,
1108                 flush_pending_writes(conf));
1109         spin_unlock_irq(&conf->resync_lock);
1110 }
1111 static void unfreeze_array(struct r1conf *conf)
1112 {
1113         /* reverse the effect of the freeze */
1114         spin_lock_irq(&conf->resync_lock);
1115         conf->array_frozen = 0;
1116         spin_unlock_irq(&conf->resync_lock);
1117         wake_up(&conf->wait_barrier);
1118 }
1119
1120 static void alloc_behind_master_bio(struct r1bio *r1_bio,
1121                                            struct bio *bio)
1122 {
1123         int size = bio->bi_iter.bi_size;
1124         unsigned vcnt = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
1125         int i = 0;
1126         struct bio *behind_bio = NULL;
1127
1128         behind_bio = bio_alloc_bioset(NULL, vcnt, 0, GFP_NOIO,
1129                                       &r1_bio->mddev->bio_set);
1130         if (!behind_bio)
1131                 return;
1132
1133         /* discard op, we don't support writezero/writesame yet */
1134         if (!bio_has_data(bio)) {
1135                 behind_bio->bi_iter.bi_size = size;
1136                 goto skip_copy;
1137         }
1138
1139         behind_bio->bi_write_hint = bio->bi_write_hint;
1140
1141         while (i < vcnt && size) {
1142                 struct page *page;
1143                 int len = min_t(int, PAGE_SIZE, size);
1144
1145                 page = alloc_page(GFP_NOIO);
1146                 if (unlikely(!page))
1147                         goto free_pages;
1148
1149                 bio_add_page(behind_bio, page, len, 0);
1150
1151                 size -= len;
1152                 i++;
1153         }
1154
1155         bio_copy_data(behind_bio, bio);
1156 skip_copy:
1157         r1_bio->behind_master_bio = behind_bio;
1158         set_bit(R1BIO_BehindIO, &r1_bio->state);
1159
1160         return;
1161
1162 free_pages:
1163         pr_debug("%dB behind alloc failed, doing sync I/O\n",
1164                  bio->bi_iter.bi_size);
1165         bio_free_pages(behind_bio);
1166         bio_put(behind_bio);
1167 }
1168
1169 static void raid1_unplug(struct blk_plug_cb *cb, bool from_schedule)
1170 {
1171         struct raid1_plug_cb *plug = container_of(cb, struct raid1_plug_cb,
1172                                                   cb);
1173         struct mddev *mddev = plug->cb.data;
1174         struct r1conf *conf = mddev->private;
1175         struct bio *bio;
1176
1177         if (from_schedule || current->bio_list) {
1178                 spin_lock_irq(&conf->device_lock);
1179                 bio_list_merge(&conf->pending_bio_list, &plug->pending);
1180                 spin_unlock_irq(&conf->device_lock);
1181                 wake_up(&conf->wait_barrier);
1182                 md_wakeup_thread(mddev->thread);
1183                 kfree(plug);
1184                 return;
1185         }
1186
1187         /* we aren't scheduling, so we can do the write-out directly. */
1188         bio = bio_list_get(&plug->pending);
1189         flush_bio_list(conf, bio);
1190         kfree(plug);
1191 }
1192
1193 static void init_r1bio(struct r1bio *r1_bio, struct mddev *mddev, struct bio *bio)
1194 {
1195         r1_bio->master_bio = bio;
1196         r1_bio->sectors = bio_sectors(bio);
1197         r1_bio->state = 0;
1198         r1_bio->mddev = mddev;
1199         r1_bio->sector = bio->bi_iter.bi_sector;
1200 }
1201
1202 static inline struct r1bio *
1203 alloc_r1bio(struct mddev *mddev, struct bio *bio)
1204 {
1205         struct r1conf *conf = mddev->private;
1206         struct r1bio *r1_bio;
1207
1208         r1_bio = mempool_alloc(&conf->r1bio_pool, GFP_NOIO);
1209         /* Ensure no bio records IO_BLOCKED */
1210         memset(r1_bio->bios, 0, conf->raid_disks * sizeof(r1_bio->bios[0]));
1211         init_r1bio(r1_bio, mddev, bio);
1212         return r1_bio;
1213 }
1214
1215 static void raid1_read_request(struct mddev *mddev, struct bio *bio,
1216                                int max_read_sectors, struct r1bio *r1_bio)
1217 {
1218         struct r1conf *conf = mddev->private;
1219         struct raid1_info *mirror;
1220         struct bio *read_bio;
1221         struct bitmap *bitmap = mddev->bitmap;
1222         const int op = bio_op(bio);
1223         const unsigned long do_sync = (bio->bi_opf & REQ_SYNC);
1224         int max_sectors;
1225         int rdisk;
1226         bool r1bio_existed = !!r1_bio;
1227         char b[BDEVNAME_SIZE];
1228
1229         /*
1230          * If r1_bio is set, we are blocking the raid1d thread
1231          * so there is a tiny risk of deadlock.  So ask for
1232          * emergency memory if needed.
1233          */
1234         gfp_t gfp = r1_bio ? (GFP_NOIO | __GFP_HIGH) : GFP_NOIO;
1235
1236         if (r1bio_existed) {
1237                 /* Need to get the block device name carefully */
1238                 struct md_rdev *rdev;
1239                 rcu_read_lock();
1240                 rdev = rcu_dereference(conf->mirrors[r1_bio->read_disk].rdev);
1241                 if (rdev)
1242                         bdevname(rdev->bdev, b);
1243                 else
1244                         strcpy(b, "???");
1245                 rcu_read_unlock();
1246         }
1247
1248         /*
1249          * Still need barrier for READ in case that whole
1250          * array is frozen.
1251          */
1252         if (!wait_read_barrier(conf, bio->bi_iter.bi_sector,
1253                                 bio->bi_opf & REQ_NOWAIT)) {
1254                 bio_wouldblock_error(bio);
1255                 return;
1256         }
1257
1258         if (!r1_bio)
1259                 r1_bio = alloc_r1bio(mddev, bio);
1260         else
1261                 init_r1bio(r1_bio, mddev, bio);
1262         r1_bio->sectors = max_read_sectors;
1263
1264         /*
1265          * make_request() can abort the operation when read-ahead is being
1266          * used and no empty request is available.
1267          */
1268         rdisk = read_balance(conf, r1_bio, &max_sectors);
1269
1270         if (rdisk < 0) {
1271                 /* couldn't find anywhere to read from */
1272                 if (r1bio_existed) {
1273                         pr_crit_ratelimited("md/raid1:%s: %s: unrecoverable I/O read error for block %llu\n",
1274                                             mdname(mddev),
1275                                             b,
1276                                             (unsigned long long)r1_bio->sector);
1277                 }
1278                 raid_end_bio_io(r1_bio);
1279                 return;
1280         }
1281         mirror = conf->mirrors + rdisk;
1282
1283         if (r1bio_existed)
1284                 pr_info_ratelimited("md/raid1:%s: redirecting sector %llu to other mirror: %s\n",
1285                                     mdname(mddev),
1286                                     (unsigned long long)r1_bio->sector,
1287                                     bdevname(mirror->rdev->bdev, b));
1288
1289         if (test_bit(WriteMostly, &mirror->rdev->flags) &&
1290             bitmap) {
1291                 /*
1292                  * Reading from a write-mostly device must take care not to
1293                  * over-take any writes that are 'behind'
1294                  */
1295                 raid1_log(mddev, "wait behind writes");
1296                 wait_event(bitmap->behind_wait,
1297                            atomic_read(&bitmap->behind_writes) == 0);
1298         }
1299
1300         if (max_sectors < bio_sectors(bio)) {
1301                 struct bio *split = bio_split(bio, max_sectors,
1302                                               gfp, &conf->bio_split);
1303                 bio_chain(split, bio);
1304                 submit_bio_noacct(bio);
1305                 bio = split;
1306                 r1_bio->master_bio = bio;
1307                 r1_bio->sectors = max_sectors;
1308         }
1309
1310         r1_bio->read_disk = rdisk;
1311
1312         if (!r1bio_existed && blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
1313                 r1_bio->start_time = bio_start_io_acct(bio);
1314
1315         read_bio = bio_alloc_clone(mirror->rdev->bdev, bio, gfp,
1316                                    &mddev->bio_set);
1317
1318         r1_bio->bios[rdisk] = read_bio;
1319
1320         read_bio->bi_iter.bi_sector = r1_bio->sector +
1321                 mirror->rdev->data_offset;
1322         read_bio->bi_end_io = raid1_end_read_request;
1323         bio_set_op_attrs(read_bio, op, do_sync);
1324         if (test_bit(FailFast, &mirror->rdev->flags) &&
1325             test_bit(R1BIO_FailFast, &r1_bio->state))
1326                 read_bio->bi_opf |= MD_FAILFAST;
1327         read_bio->bi_private = r1_bio;
1328
1329         if (mddev->gendisk)
1330                 trace_block_bio_remap(read_bio, disk_devt(mddev->gendisk),
1331                                       r1_bio->sector);
1332
1333         submit_bio_noacct(read_bio);
1334 }
1335
1336 static void raid1_write_request(struct mddev *mddev, struct bio *bio,
1337                                 int max_write_sectors)
1338 {
1339         struct r1conf *conf = mddev->private;
1340         struct r1bio *r1_bio;
1341         int i, disks;
1342         struct bitmap *bitmap = mddev->bitmap;
1343         unsigned long flags;
1344         struct md_rdev *blocked_rdev;
1345         struct blk_plug_cb *cb;
1346         struct raid1_plug_cb *plug = NULL;
1347         int first_clone;
1348         int max_sectors;
1349         bool write_behind = false;
1350
1351         if (mddev_is_clustered(mddev) &&
1352              md_cluster_ops->area_resyncing(mddev, WRITE,
1353                      bio->bi_iter.bi_sector, bio_end_sector(bio))) {
1354
1355                 DEFINE_WAIT(w);
1356                 if (bio->bi_opf & REQ_NOWAIT) {
1357                         bio_wouldblock_error(bio);
1358                         return;
1359                 }
1360                 for (;;) {
1361                         prepare_to_wait(&conf->wait_barrier,
1362                                         &w, TASK_IDLE);
1363                         if (!md_cluster_ops->area_resyncing(mddev, WRITE,
1364                                                         bio->bi_iter.bi_sector,
1365                                                         bio_end_sector(bio)))
1366                                 break;
1367                         schedule();
1368                 }
1369                 finish_wait(&conf->wait_barrier, &w);
1370         }
1371
1372         /*
1373          * Register the new request and wait if the reconstruction
1374          * thread has put up a bar for new requests.
1375          * Continue immediately if no resync is active currently.
1376          */
1377         if (!wait_barrier(conf, bio->bi_iter.bi_sector,
1378                                 bio->bi_opf & REQ_NOWAIT)) {
1379                 bio_wouldblock_error(bio);
1380                 return;
1381         }
1382
1383         r1_bio = alloc_r1bio(mddev, bio);
1384         r1_bio->sectors = max_write_sectors;
1385
1386         /* first select target devices under rcu_lock and
1387          * inc refcount on their rdev.  Record them by setting
1388          * bios[x] to bio
1389          * If there are known/acknowledged bad blocks on any device on
1390          * which we have seen a write error, we want to avoid writing those
1391          * blocks.
1392          * This potentially requires several writes to write around
1393          * the bad blocks.  Each set of writes gets it's own r1bio
1394          * with a set of bios attached.
1395          */
1396
1397         disks = conf->raid_disks * 2;
1398  retry_write:
1399         blocked_rdev = NULL;
1400         rcu_read_lock();
1401         max_sectors = r1_bio->sectors;
1402         for (i = 0;  i < disks; i++) {
1403                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1404
1405                 /*
1406                  * The write-behind io is only attempted on drives marked as
1407                  * write-mostly, which means we could allocate write behind
1408                  * bio later.
1409                  */
1410                 if (rdev && test_bit(WriteMostly, &rdev->flags))
1411                         write_behind = true;
1412
1413                 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
1414                         atomic_inc(&rdev->nr_pending);
1415                         blocked_rdev = rdev;
1416                         break;
1417                 }
1418                 r1_bio->bios[i] = NULL;
1419                 if (!rdev || test_bit(Faulty, &rdev->flags)) {
1420                         if (i < conf->raid_disks)
1421                                 set_bit(R1BIO_Degraded, &r1_bio->state);
1422                         continue;
1423                 }
1424
1425                 atomic_inc(&rdev->nr_pending);
1426                 if (test_bit(WriteErrorSeen, &rdev->flags)) {
1427                         sector_t first_bad;
1428                         int bad_sectors;
1429                         int is_bad;
1430
1431                         is_bad = is_badblock(rdev, r1_bio->sector, max_sectors,
1432                                              &first_bad, &bad_sectors);
1433                         if (is_bad < 0) {
1434                                 /* mustn't write here until the bad block is
1435                                  * acknowledged*/
1436                                 set_bit(BlockedBadBlocks, &rdev->flags);
1437                                 blocked_rdev = rdev;
1438                                 break;
1439                         }
1440                         if (is_bad && first_bad <= r1_bio->sector) {
1441                                 /* Cannot write here at all */
1442                                 bad_sectors -= (r1_bio->sector - first_bad);
1443                                 if (bad_sectors < max_sectors)
1444                                         /* mustn't write more than bad_sectors
1445                                          * to other devices yet
1446                                          */
1447                                         max_sectors = bad_sectors;
1448                                 rdev_dec_pending(rdev, mddev);
1449                                 /* We don't set R1BIO_Degraded as that
1450                                  * only applies if the disk is
1451                                  * missing, so it might be re-added,
1452                                  * and we want to know to recover this
1453                                  * chunk.
1454                                  * In this case the device is here,
1455                                  * and the fact that this chunk is not
1456                                  * in-sync is recorded in the bad
1457                                  * block log
1458                                  */
1459                                 continue;
1460                         }
1461                         if (is_bad) {
1462                                 int good_sectors = first_bad - r1_bio->sector;
1463                                 if (good_sectors < max_sectors)
1464                                         max_sectors = good_sectors;
1465                         }
1466                 }
1467                 r1_bio->bios[i] = bio;
1468         }
1469         rcu_read_unlock();
1470
1471         if (unlikely(blocked_rdev)) {
1472                 /* Wait for this device to become unblocked */
1473                 int j;
1474
1475                 for (j = 0; j < i; j++)
1476                         if (r1_bio->bios[j])
1477                                 rdev_dec_pending(conf->mirrors[j].rdev, mddev);
1478                 r1_bio->state = 0;
1479                 allow_barrier(conf, bio->bi_iter.bi_sector);
1480
1481                 if (bio->bi_opf & REQ_NOWAIT) {
1482                         bio_wouldblock_error(bio);
1483                         return;
1484                 }
1485                 raid1_log(mddev, "wait rdev %d blocked", blocked_rdev->raid_disk);
1486                 md_wait_for_blocked_rdev(blocked_rdev, mddev);
1487                 wait_barrier(conf, bio->bi_iter.bi_sector, false);
1488                 goto retry_write;
1489         }
1490
1491         /*
1492          * When using a bitmap, we may call alloc_behind_master_bio below.
1493          * alloc_behind_master_bio allocates a copy of the data payload a page
1494          * at a time and thus needs a new bio that can fit the whole payload
1495          * this bio in page sized chunks.
1496          */
1497         if (write_behind && bitmap)
1498                 max_sectors = min_t(int, max_sectors,
1499                                     BIO_MAX_VECS * (PAGE_SIZE >> 9));
1500         if (max_sectors < bio_sectors(bio)) {
1501                 struct bio *split = bio_split(bio, max_sectors,
1502                                               GFP_NOIO, &conf->bio_split);
1503                 bio_chain(split, bio);
1504                 submit_bio_noacct(bio);
1505                 bio = split;
1506                 r1_bio->master_bio = bio;
1507                 r1_bio->sectors = max_sectors;
1508         }
1509
1510         if (blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
1511                 r1_bio->start_time = bio_start_io_acct(bio);
1512         atomic_set(&r1_bio->remaining, 1);
1513         atomic_set(&r1_bio->behind_remaining, 0);
1514
1515         first_clone = 1;
1516
1517         for (i = 0; i < disks; i++) {
1518                 struct bio *mbio = NULL;
1519                 struct md_rdev *rdev = conf->mirrors[i].rdev;
1520                 if (!r1_bio->bios[i])
1521                         continue;
1522
1523                 if (first_clone) {
1524                         /* do behind I/O ?
1525                          * Not if there are too many, or cannot
1526                          * allocate memory, or a reader on WriteMostly
1527                          * is waiting for behind writes to flush */
1528                         if (bitmap &&
1529                             test_bit(WriteMostly, &rdev->flags) &&
1530                             (atomic_read(&bitmap->behind_writes)
1531                              < mddev->bitmap_info.max_write_behind) &&
1532                             !waitqueue_active(&bitmap->behind_wait)) {
1533                                 alloc_behind_master_bio(r1_bio, bio);
1534                         }
1535
1536                         md_bitmap_startwrite(bitmap, r1_bio->sector, r1_bio->sectors,
1537                                              test_bit(R1BIO_BehindIO, &r1_bio->state));
1538                         first_clone = 0;
1539                 }
1540
1541                 if (r1_bio->behind_master_bio) {
1542                         mbio = bio_alloc_clone(rdev->bdev,
1543                                                r1_bio->behind_master_bio,
1544                                                GFP_NOIO, &mddev->bio_set);
1545                         if (test_bit(CollisionCheck, &rdev->flags))
1546                                 wait_for_serialization(rdev, r1_bio);
1547                         if (test_bit(WriteMostly, &rdev->flags))
1548                                 atomic_inc(&r1_bio->behind_remaining);
1549                 } else {
1550                         mbio = bio_alloc_clone(rdev->bdev, bio, GFP_NOIO,
1551                                                &mddev->bio_set);
1552
1553                         if (mddev->serialize_policy)
1554                                 wait_for_serialization(rdev, r1_bio);
1555                 }
1556
1557                 r1_bio->bios[i] = mbio;
1558
1559                 mbio->bi_iter.bi_sector = (r1_bio->sector + rdev->data_offset);
1560                 mbio->bi_end_io = raid1_end_write_request;
1561                 mbio->bi_opf = bio_op(bio) | (bio->bi_opf & (REQ_SYNC | REQ_FUA));
1562                 if (test_bit(FailFast, &rdev->flags) &&
1563                     !test_bit(WriteMostly, &rdev->flags) &&
1564                     conf->raid_disks - mddev->degraded > 1)
1565                         mbio->bi_opf |= MD_FAILFAST;
1566                 mbio->bi_private = r1_bio;
1567
1568                 atomic_inc(&r1_bio->remaining);
1569
1570                 if (mddev->gendisk)
1571                         trace_block_bio_remap(mbio, disk_devt(mddev->gendisk),
1572                                               r1_bio->sector);
1573                 /* flush_pending_writes() needs access to the rdev so...*/
1574                 mbio->bi_bdev = (void *)rdev;
1575
1576                 cb = blk_check_plugged(raid1_unplug, mddev, sizeof(*plug));
1577                 if (cb)
1578                         plug = container_of(cb, struct raid1_plug_cb, cb);
1579                 else
1580                         plug = NULL;
1581                 if (plug) {
1582                         bio_list_add(&plug->pending, mbio);
1583                 } else {
1584                         spin_lock_irqsave(&conf->device_lock, flags);
1585                         bio_list_add(&conf->pending_bio_list, mbio);
1586                         spin_unlock_irqrestore(&conf->device_lock, flags);
1587                         md_wakeup_thread(mddev->thread);
1588                 }
1589         }
1590
1591         r1_bio_write_done(r1_bio);
1592
1593         /* In case raid1d snuck in to freeze_array */
1594         wake_up(&conf->wait_barrier);
1595 }
1596
1597 static bool raid1_make_request(struct mddev *mddev, struct bio *bio)
1598 {
1599         sector_t sectors;
1600
1601         if (unlikely(bio->bi_opf & REQ_PREFLUSH)
1602             && md_flush_request(mddev, bio))
1603                 return true;
1604
1605         /*
1606          * There is a limit to the maximum size, but
1607          * the read/write handler might find a lower limit
1608          * due to bad blocks.  To avoid multiple splits,
1609          * we pass the maximum number of sectors down
1610          * and let the lower level perform the split.
1611          */
1612         sectors = align_to_barrier_unit_end(
1613                 bio->bi_iter.bi_sector, bio_sectors(bio));
1614
1615         if (bio_data_dir(bio) == READ)
1616                 raid1_read_request(mddev, bio, sectors, NULL);
1617         else {
1618                 if (!md_write_start(mddev,bio))
1619                         return false;
1620                 raid1_write_request(mddev, bio, sectors);
1621         }
1622         return true;
1623 }
1624
1625 static void raid1_status(struct seq_file *seq, struct mddev *mddev)
1626 {
1627         struct r1conf *conf = mddev->private;
1628         int i;
1629
1630         seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1631                    conf->raid_disks - mddev->degraded);
1632         rcu_read_lock();
1633         for (i = 0; i < conf->raid_disks; i++) {
1634                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1635                 seq_printf(seq, "%s",
1636                            rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1637         }
1638         rcu_read_unlock();
1639         seq_printf(seq, "]");
1640 }
1641
1642 static void raid1_error(struct mddev *mddev, struct md_rdev *rdev)
1643 {
1644         char b[BDEVNAME_SIZE];
1645         struct r1conf *conf = mddev->private;
1646         unsigned long flags;
1647
1648         /*
1649          * If it is not operational, then we have already marked it as dead
1650          * else if it is the last working disks with "fail_last_dev == false",
1651          * ignore the error, let the next level up know.
1652          * else mark the drive as failed
1653          */
1654         spin_lock_irqsave(&conf->device_lock, flags);
1655         if (test_bit(In_sync, &rdev->flags) && !mddev->fail_last_dev
1656             && (conf->raid_disks - mddev->degraded) == 1) {
1657                 /*
1658                  * Don't fail the drive, act as though we were just a
1659                  * normal single drive.
1660                  * However don't try a recovery from this drive as
1661                  * it is very likely to fail.
1662                  */
1663                 conf->recovery_disabled = mddev->recovery_disabled;
1664                 spin_unlock_irqrestore(&conf->device_lock, flags);
1665                 return;
1666         }
1667         set_bit(Blocked, &rdev->flags);
1668         if (test_and_clear_bit(In_sync, &rdev->flags))
1669                 mddev->degraded++;
1670         set_bit(Faulty, &rdev->flags);
1671         spin_unlock_irqrestore(&conf->device_lock, flags);
1672         /*
1673          * if recovery is running, make sure it aborts.
1674          */
1675         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1676         set_mask_bits(&mddev->sb_flags, 0,
1677                       BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
1678         pr_crit("md/raid1:%s: Disk failure on %s, disabling device.\n"
1679                 "md/raid1:%s: Operation continuing on %d devices.\n",
1680                 mdname(mddev), bdevname(rdev->bdev, b),
1681                 mdname(mddev), conf->raid_disks - mddev->degraded);
1682 }
1683
1684 static void print_conf(struct r1conf *conf)
1685 {
1686         int i;
1687
1688         pr_debug("RAID1 conf printout:\n");
1689         if (!conf) {
1690                 pr_debug("(!conf)\n");
1691                 return;
1692         }
1693         pr_debug(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1694                  conf->raid_disks);
1695
1696         rcu_read_lock();
1697         for (i = 0; i < conf->raid_disks; i++) {
1698                 char b[BDEVNAME_SIZE];
1699                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1700                 if (rdev)
1701                         pr_debug(" disk %d, wo:%d, o:%d, dev:%s\n",
1702                                  i, !test_bit(In_sync, &rdev->flags),
1703                                  !test_bit(Faulty, &rdev->flags),
1704                                  bdevname(rdev->bdev,b));
1705         }
1706         rcu_read_unlock();
1707 }
1708
1709 static void close_sync(struct r1conf *conf)
1710 {
1711         int idx;
1712
1713         for (idx = 0; idx < BARRIER_BUCKETS_NR; idx++) {
1714                 _wait_barrier(conf, idx, false);
1715                 _allow_barrier(conf, idx);
1716         }
1717
1718         mempool_exit(&conf->r1buf_pool);
1719 }
1720
1721 static int raid1_spare_active(struct mddev *mddev)
1722 {
1723         int i;
1724         struct r1conf *conf = mddev->private;
1725         int count = 0;
1726         unsigned long flags;
1727
1728         /*
1729          * Find all failed disks within the RAID1 configuration
1730          * and mark them readable.
1731          * Called under mddev lock, so rcu protection not needed.
1732          * device_lock used to avoid races with raid1_end_read_request
1733          * which expects 'In_sync' flags and ->degraded to be consistent.
1734          */
1735         spin_lock_irqsave(&conf->device_lock, flags);
1736         for (i = 0; i < conf->raid_disks; i++) {
1737                 struct md_rdev *rdev = conf->mirrors[i].rdev;
1738                 struct md_rdev *repl = conf->mirrors[conf->raid_disks + i].rdev;
1739                 if (repl
1740                     && !test_bit(Candidate, &repl->flags)
1741                     && repl->recovery_offset == MaxSector
1742                     && !test_bit(Faulty, &repl->flags)
1743                     && !test_and_set_bit(In_sync, &repl->flags)) {
1744                         /* replacement has just become active */
1745                         if (!rdev ||
1746                             !test_and_clear_bit(In_sync, &rdev->flags))
1747                                 count++;
1748                         if (rdev) {
1749                                 /* Replaced device not technically
1750                                  * faulty, but we need to be sure
1751                                  * it gets removed and never re-added
1752                                  */
1753                                 set_bit(Faulty, &rdev->flags);
1754                                 sysfs_notify_dirent_safe(
1755                                         rdev->sysfs_state);
1756                         }
1757                 }
1758                 if (rdev
1759                     && rdev->recovery_offset == MaxSector
1760                     && !test_bit(Faulty, &rdev->flags)
1761                     && !test_and_set_bit(In_sync, &rdev->flags)) {
1762                         count++;
1763                         sysfs_notify_dirent_safe(rdev->sysfs_state);
1764                 }
1765         }
1766         mddev->degraded -= count;
1767         spin_unlock_irqrestore(&conf->device_lock, flags);
1768
1769         print_conf(conf);
1770         return count;
1771 }
1772
1773 static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
1774 {
1775         struct r1conf *conf = mddev->private;
1776         int err = -EEXIST;
1777         int mirror = 0;
1778         struct raid1_info *p;
1779         int first = 0;
1780         int last = conf->raid_disks - 1;
1781
1782         if (mddev->recovery_disabled == conf->recovery_disabled)
1783                 return -EBUSY;
1784
1785         if (md_integrity_add_rdev(rdev, mddev))
1786                 return -ENXIO;
1787
1788         if (rdev->raid_disk >= 0)
1789                 first = last = rdev->raid_disk;
1790
1791         /*
1792          * find the disk ... but prefer rdev->saved_raid_disk
1793          * if possible.
1794          */
1795         if (rdev->saved_raid_disk >= 0 &&
1796             rdev->saved_raid_disk >= first &&
1797             rdev->saved_raid_disk < conf->raid_disks &&
1798             conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
1799                 first = last = rdev->saved_raid_disk;
1800
1801         for (mirror = first; mirror <= last; mirror++) {
1802                 p = conf->mirrors + mirror;
1803                 if (!p->rdev) {
1804                         if (mddev->gendisk)
1805                                 disk_stack_limits(mddev->gendisk, rdev->bdev,
1806                                                   rdev->data_offset << 9);
1807
1808                         p->head_position = 0;
1809                         rdev->raid_disk = mirror;
1810                         err = 0;
1811                         /* As all devices are equivalent, we don't need a full recovery
1812                          * if this was recently any drive of the array
1813                          */
1814                         if (rdev->saved_raid_disk < 0)
1815                                 conf->fullsync = 1;
1816                         rcu_assign_pointer(p->rdev, rdev);
1817                         break;
1818                 }
1819                 if (test_bit(WantReplacement, &p->rdev->flags) &&
1820                     p[conf->raid_disks].rdev == NULL) {
1821                         /* Add this device as a replacement */
1822                         clear_bit(In_sync, &rdev->flags);
1823                         set_bit(Replacement, &rdev->flags);
1824                         rdev->raid_disk = mirror;
1825                         err = 0;
1826                         conf->fullsync = 1;
1827                         rcu_assign_pointer(p[conf->raid_disks].rdev, rdev);
1828                         break;
1829                 }
1830         }
1831         if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
1832                 blk_queue_flag_set(QUEUE_FLAG_DISCARD, mddev->queue);
1833         print_conf(conf);
1834         return err;
1835 }
1836
1837 static int raid1_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
1838 {
1839         struct r1conf *conf = mddev->private;
1840         int err = 0;
1841         int number = rdev->raid_disk;
1842         struct raid1_info *p = conf->mirrors + number;
1843
1844         if (rdev != p->rdev)
1845                 p = conf->mirrors + conf->raid_disks + number;
1846
1847         print_conf(conf);
1848         if (rdev == p->rdev) {
1849                 if (test_bit(In_sync, &rdev->flags) ||
1850                     atomic_read(&rdev->nr_pending)) {
1851                         err = -EBUSY;
1852                         goto abort;
1853                 }
1854                 /* Only remove non-faulty devices if recovery
1855                  * is not possible.
1856                  */
1857                 if (!test_bit(Faulty, &rdev->flags) &&
1858                     mddev->recovery_disabled != conf->recovery_disabled &&
1859                     mddev->degraded < conf->raid_disks) {
1860                         err = -EBUSY;
1861                         goto abort;
1862                 }
1863                 p->rdev = NULL;
1864                 if (!test_bit(RemoveSynchronized, &rdev->flags)) {
1865                         synchronize_rcu();
1866                         if (atomic_read(&rdev->nr_pending)) {
1867                                 /* lost the race, try later */
1868                                 err = -EBUSY;
1869                                 p->rdev = rdev;
1870                                 goto abort;
1871                         }
1872                 }
1873                 if (conf->mirrors[conf->raid_disks + number].rdev) {
1874                         /* We just removed a device that is being replaced.
1875                          * Move down the replacement.  We drain all IO before
1876                          * doing this to avoid confusion.
1877                          */
1878                         struct md_rdev *repl =
1879                                 conf->mirrors[conf->raid_disks + number].rdev;
1880                         freeze_array(conf, 0);
1881                         if (atomic_read(&repl->nr_pending)) {
1882                                 /* It means that some queued IO of retry_list
1883                                  * hold repl. Thus, we cannot set replacement
1884                                  * as NULL, avoiding rdev NULL pointer
1885                                  * dereference in sync_request_write and
1886                                  * handle_write_finished.
1887                                  */
1888                                 err = -EBUSY;
1889                                 unfreeze_array(conf);
1890                                 goto abort;
1891                         }
1892                         clear_bit(Replacement, &repl->flags);
1893                         p->rdev = repl;
1894                         conf->mirrors[conf->raid_disks + number].rdev = NULL;
1895                         unfreeze_array(conf);
1896                 }
1897
1898                 clear_bit(WantReplacement, &rdev->flags);
1899                 err = md_integrity_register(mddev);
1900         }
1901 abort:
1902
1903         print_conf(conf);
1904         return err;
1905 }
1906
1907 static void end_sync_read(struct bio *bio)
1908 {
1909         struct r1bio *r1_bio = get_resync_r1bio(bio);
1910
1911         update_head_pos(r1_bio->read_disk, r1_bio);
1912
1913         /*
1914          * we have read a block, now it needs to be re-written,
1915          * or re-read if the read failed.
1916          * We don't do much here, just schedule handling by raid1d
1917          */
1918         if (!bio->bi_status)
1919                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1920
1921         if (atomic_dec_and_test(&r1_bio->remaining))
1922                 reschedule_retry(r1_bio);
1923 }
1924
1925 static void abort_sync_write(struct mddev *mddev, struct r1bio *r1_bio)
1926 {
1927         sector_t sync_blocks = 0;
1928         sector_t s = r1_bio->sector;
1929         long sectors_to_go = r1_bio->sectors;
1930
1931         /* make sure these bits don't get cleared. */
1932         do {
1933                 md_bitmap_end_sync(mddev->bitmap, s, &sync_blocks, 1);
1934                 s += sync_blocks;
1935                 sectors_to_go -= sync_blocks;
1936         } while (sectors_to_go > 0);
1937 }
1938
1939 static void put_sync_write_buf(struct r1bio *r1_bio, int uptodate)
1940 {
1941         if (atomic_dec_and_test(&r1_bio->remaining)) {
1942                 struct mddev *mddev = r1_bio->mddev;
1943                 int s = r1_bio->sectors;
1944
1945                 if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
1946                     test_bit(R1BIO_WriteError, &r1_bio->state))
1947                         reschedule_retry(r1_bio);
1948                 else {
1949                         put_buf(r1_bio);
1950                         md_done_sync(mddev, s, uptodate);
1951                 }
1952         }
1953 }
1954
1955 static void end_sync_write(struct bio *bio)
1956 {
1957         int uptodate = !bio->bi_status;
1958         struct r1bio *r1_bio = get_resync_r1bio(bio);
1959         struct mddev *mddev = r1_bio->mddev;
1960         struct r1conf *conf = mddev->private;
1961         sector_t first_bad;
1962         int bad_sectors;
1963         struct md_rdev *rdev = conf->mirrors[find_bio_disk(r1_bio, bio)].rdev;
1964
1965         if (!uptodate) {
1966                 abort_sync_write(mddev, r1_bio);
1967                 set_bit(WriteErrorSeen, &rdev->flags);
1968                 if (!test_and_set_bit(WantReplacement, &rdev->flags))
1969                         set_bit(MD_RECOVERY_NEEDED, &
1970                                 mddev->recovery);
1971                 set_bit(R1BIO_WriteError, &r1_bio->state);
1972         } else if (is_badblock(rdev, r1_bio->sector, r1_bio->sectors,
1973                                &first_bad, &bad_sectors) &&
1974                    !is_badblock(conf->mirrors[r1_bio->read_disk].rdev,
1975                                 r1_bio->sector,
1976                                 r1_bio->sectors,
1977                                 &first_bad, &bad_sectors)
1978                 )
1979                 set_bit(R1BIO_MadeGood, &r1_bio->state);
1980
1981         put_sync_write_buf(r1_bio, uptodate);
1982 }
1983
1984 static int r1_sync_page_io(struct md_rdev *rdev, sector_t sector,
1985                             int sectors, struct page *page, int rw)
1986 {
1987         if (sync_page_io(rdev, sector, sectors << 9, page, rw, 0, false))
1988                 /* success */
1989                 return 1;
1990         if (rw == WRITE) {
1991                 set_bit(WriteErrorSeen, &rdev->flags);
1992                 if (!test_and_set_bit(WantReplacement,
1993                                       &rdev->flags))
1994                         set_bit(MD_RECOVERY_NEEDED, &
1995                                 rdev->mddev->recovery);
1996         }
1997         /* need to record an error - either for the block or the device */
1998         if (!rdev_set_badblocks(rdev, sector, sectors, 0))
1999                 md_error(rdev->mddev, rdev);
2000         return 0;
2001 }
2002
2003 static int fix_sync_read_error(struct r1bio *r1_bio)
2004 {
2005         /* Try some synchronous reads of other devices to get
2006          * good data, much like with normal read errors.  Only
2007          * read into the pages we already have so we don't
2008          * need to re-issue the read request.
2009          * We don't need to freeze the array, because being in an
2010          * active sync request, there is no normal IO, and
2011          * no overlapping syncs.
2012          * We don't need to check is_badblock() again as we
2013          * made sure that anything with a bad block in range
2014          * will have bi_end_io clear.
2015          */
2016         struct mddev *mddev = r1_bio->mddev;
2017         struct r1conf *conf = mddev->private;
2018         struct bio *bio = r1_bio->bios[r1_bio->read_disk];
2019         struct page **pages = get_resync_pages(bio)->pages;
2020         sector_t sect = r1_bio->sector;
2021         int sectors = r1_bio->sectors;
2022         int idx = 0;
2023         struct md_rdev *rdev;
2024
2025         rdev = conf->mirrors[r1_bio->read_disk].rdev;
2026         if (test_bit(FailFast, &rdev->flags)) {
2027                 /* Don't try recovering from here - just fail it
2028                  * ... unless it is the last working device of course */
2029                 md_error(mddev, rdev);
2030                 if (test_bit(Faulty, &rdev->flags))
2031                         /* Don't try to read from here, but make sure
2032                          * put_buf does it's thing
2033                          */
2034                         bio->bi_end_io = end_sync_write;
2035         }
2036
2037         while(sectors) {
2038                 int s = sectors;
2039                 int d = r1_bio->read_disk;
2040                 int success = 0;
2041                 int start;
2042
2043                 if (s > (PAGE_SIZE>>9))
2044                         s = PAGE_SIZE >> 9;
2045                 do {
2046                         if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
2047                                 /* No rcu protection needed here devices
2048                                  * can only be removed when no resync is
2049                                  * active, and resync is currently active
2050                                  */
2051                                 rdev = conf->mirrors[d].rdev;
2052                                 if (sync_page_io(rdev, sect, s<<9,
2053                                                  pages[idx],
2054                                                  REQ_OP_READ, 0, false)) {
2055                                         success = 1;
2056                                         break;
2057                                 }
2058                         }
2059                         d++;
2060                         if (d == conf->raid_disks * 2)
2061                                 d = 0;
2062                 } while (!success && d != r1_bio->read_disk);
2063
2064                 if (!success) {
2065                         int abort = 0;
2066                         /* Cannot read from anywhere, this block is lost.
2067                          * Record a bad block on each device.  If that doesn't
2068                          * work just disable and interrupt the recovery.
2069                          * Don't fail devices as that won't really help.
2070                          */
2071                         pr_crit_ratelimited("md/raid1:%s: %pg: unrecoverable I/O read error for block %llu\n",
2072                                             mdname(mddev), bio->bi_bdev,
2073                                             (unsigned long long)r1_bio->sector);
2074                         for (d = 0; d < conf->raid_disks * 2; d++) {
2075                                 rdev = conf->mirrors[d].rdev;
2076                                 if (!rdev || test_bit(Faulty, &rdev->flags))
2077                                         continue;
2078                                 if (!rdev_set_badblocks(rdev, sect, s, 0))
2079                                         abort = 1;
2080                         }
2081                         if (abort) {
2082                                 conf->recovery_disabled =
2083                                         mddev->recovery_disabled;
2084                                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2085                                 md_done_sync(mddev, r1_bio->sectors, 0);
2086                                 put_buf(r1_bio);
2087                                 return 0;
2088                         }
2089                         /* Try next page */
2090                         sectors -= s;
2091                         sect += s;
2092                         idx++;
2093                         continue;
2094                 }
2095
2096                 start = d;
2097                 /* write it back and re-read */
2098                 while (d != r1_bio->read_disk) {
2099                         if (d == 0)
2100                                 d = conf->raid_disks * 2;
2101                         d--;
2102                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
2103                                 continue;
2104                         rdev = conf->mirrors[d].rdev;
2105                         if (r1_sync_page_io(rdev, sect, s,
2106                                             pages[idx],
2107                                             WRITE) == 0) {
2108                                 r1_bio->bios[d]->bi_end_io = NULL;
2109                                 rdev_dec_pending(rdev, mddev);
2110                         }
2111                 }
2112                 d = start;
2113                 while (d != r1_bio->read_disk) {
2114                         if (d == 0)
2115                                 d = conf->raid_disks * 2;
2116                         d--;
2117                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
2118                                 continue;
2119                         rdev = conf->mirrors[d].rdev;
2120                         if (r1_sync_page_io(rdev, sect, s,
2121                                             pages[idx],
2122                                             READ) != 0)
2123                                 atomic_add(s, &rdev->corrected_errors);
2124                 }
2125                 sectors -= s;
2126                 sect += s;
2127                 idx ++;
2128         }
2129         set_bit(R1BIO_Uptodate, &r1_bio->state);
2130         bio->bi_status = 0;
2131         return 1;
2132 }
2133
2134 static void process_checks(struct r1bio *r1_bio)
2135 {
2136         /* We have read all readable devices.  If we haven't
2137          * got the block, then there is no hope left.
2138          * If we have, then we want to do a comparison
2139          * and skip the write if everything is the same.
2140          * If any blocks failed to read, then we need to
2141          * attempt an over-write
2142          */
2143         struct mddev *mddev = r1_bio->mddev;
2144         struct r1conf *conf = mddev->private;
2145         int primary;
2146         int i;
2147         int vcnt;
2148
2149         /* Fix variable parts of all bios */
2150         vcnt = (r1_bio->sectors + PAGE_SIZE / 512 - 1) >> (PAGE_SHIFT - 9);
2151         for (i = 0; i < conf->raid_disks * 2; i++) {
2152                 blk_status_t status;
2153                 struct bio *b = r1_bio->bios[i];
2154                 struct resync_pages *rp = get_resync_pages(b);
2155                 if (b->bi_end_io != end_sync_read)
2156                         continue;
2157                 /* fixup the bio for reuse, but preserve errno */
2158                 status = b->bi_status;
2159                 bio_reset(b, conf->mirrors[i].rdev->bdev, REQ_OP_READ);
2160                 b->bi_status = status;
2161                 b->bi_iter.bi_sector = r1_bio->sector +
2162                         conf->mirrors[i].rdev->data_offset;
2163                 b->bi_end_io = end_sync_read;
2164                 rp->raid_bio = r1_bio;
2165                 b->bi_private = rp;
2166
2167                 /* initialize bvec table again */
2168                 md_bio_reset_resync_pages(b, rp, r1_bio->sectors << 9);
2169         }
2170         for (primary = 0; primary < conf->raid_disks * 2; primary++)
2171                 if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
2172                     !r1_bio->bios[primary]->bi_status) {
2173                         r1_bio->bios[primary]->bi_end_io = NULL;
2174                         rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
2175                         break;
2176                 }
2177         r1_bio->read_disk = primary;
2178         for (i = 0; i < conf->raid_disks * 2; i++) {
2179                 int j = 0;
2180                 struct bio *pbio = r1_bio->bios[primary];
2181                 struct bio *sbio = r1_bio->bios[i];
2182                 blk_status_t status = sbio->bi_status;
2183                 struct page **ppages = get_resync_pages(pbio)->pages;
2184                 struct page **spages = get_resync_pages(sbio)->pages;
2185                 struct bio_vec *bi;
2186                 int page_len[RESYNC_PAGES] = { 0 };
2187                 struct bvec_iter_all iter_all;
2188
2189                 if (sbio->bi_end_io != end_sync_read)
2190                         continue;
2191                 /* Now we can 'fixup' the error value */
2192                 sbio->bi_status = 0;
2193
2194                 bio_for_each_segment_all(bi, sbio, iter_all)
2195                         page_len[j++] = bi->bv_len;
2196
2197                 if (!status) {
2198                         for (j = vcnt; j-- ; ) {
2199                                 if (memcmp(page_address(ppages[j]),
2200                                            page_address(spages[j]),
2201                                            page_len[j]))
2202                                         break;
2203                         }
2204                 } else
2205                         j = 0;
2206                 if (j >= 0)
2207                         atomic64_add(r1_bio->sectors, &mddev->resync_mismatches);
2208                 if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
2209                               && !status)) {
2210                         /* No need to write to this device. */
2211                         sbio->bi_end_io = NULL;
2212                         rdev_dec_pending(conf->mirrors[i].rdev, mddev);
2213                         continue;
2214                 }
2215
2216                 bio_copy_data(sbio, pbio);
2217         }
2218 }
2219
2220 static void sync_request_write(struct mddev *mddev, struct r1bio *r1_bio)
2221 {
2222         struct r1conf *conf = mddev->private;
2223         int i;
2224         int disks = conf->raid_disks * 2;
2225         struct bio *wbio;
2226
2227         if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
2228                 /* ouch - failed to read all of that. */
2229                 if (!fix_sync_read_error(r1_bio))
2230                         return;
2231
2232         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2233                 process_checks(r1_bio);
2234
2235         /*
2236          * schedule writes
2237          */
2238         atomic_set(&r1_bio->remaining, 1);
2239         for (i = 0; i < disks ; i++) {
2240                 wbio = r1_bio->bios[i];
2241                 if (wbio->bi_end_io == NULL ||
2242                     (wbio->bi_end_io == end_sync_read &&
2243                      (i == r1_bio->read_disk ||
2244                       !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
2245                         continue;
2246                 if (test_bit(Faulty, &conf->mirrors[i].rdev->flags)) {
2247                         abort_sync_write(mddev, r1_bio);
2248                         continue;
2249                 }
2250
2251                 bio_set_op_attrs(wbio, REQ_OP_WRITE, 0);
2252                 if (test_bit(FailFast, &conf->mirrors[i].rdev->flags))
2253                         wbio->bi_opf |= MD_FAILFAST;
2254
2255                 wbio->bi_end_io = end_sync_write;
2256                 atomic_inc(&r1_bio->remaining);
2257                 md_sync_acct(conf->mirrors[i].rdev->bdev, bio_sectors(wbio));
2258
2259                 submit_bio_noacct(wbio);
2260         }
2261
2262         put_sync_write_buf(r1_bio, 1);
2263 }
2264
2265 /*
2266  * This is a kernel thread which:
2267  *
2268  *      1.      Retries failed read operations on working mirrors.
2269  *      2.      Updates the raid superblock when problems encounter.
2270  *      3.      Performs writes following reads for array synchronising.
2271  */
2272
2273 static void fix_read_error(struct r1conf *conf, int read_disk,
2274                            sector_t sect, int sectors)
2275 {
2276         struct mddev *mddev = conf->mddev;
2277         while(sectors) {
2278                 int s = sectors;
2279                 int d = read_disk;
2280                 int success = 0;
2281                 int start;
2282                 struct md_rdev *rdev;
2283
2284                 if (s > (PAGE_SIZE>>9))
2285                         s = PAGE_SIZE >> 9;
2286
2287                 do {
2288                         sector_t first_bad;
2289                         int bad_sectors;
2290
2291                         rcu_read_lock();
2292                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2293                         if (rdev &&
2294                             (test_bit(In_sync, &rdev->flags) ||
2295                              (!test_bit(Faulty, &rdev->flags) &&
2296                               rdev->recovery_offset >= sect + s)) &&
2297                             is_badblock(rdev, sect, s,
2298                                         &first_bad, &bad_sectors) == 0) {
2299                                 atomic_inc(&rdev->nr_pending);
2300                                 rcu_read_unlock();
2301                                 if (sync_page_io(rdev, sect, s<<9,
2302                                          conf->tmppage, REQ_OP_READ, 0, false))
2303                                         success = 1;
2304                                 rdev_dec_pending(rdev, mddev);
2305                                 if (success)
2306                                         break;
2307                         } else
2308                                 rcu_read_unlock();
2309                         d++;
2310                         if (d == conf->raid_disks * 2)
2311                                 d = 0;
2312                 } while (!success && d != read_disk);
2313
2314                 if (!success) {
2315                         /* Cannot read from anywhere - mark it bad */
2316                         struct md_rdev *rdev = conf->mirrors[read_disk].rdev;
2317                         if (!rdev_set_badblocks(rdev, sect, s, 0))
2318                                 md_error(mddev, rdev);
2319                         break;
2320                 }
2321                 /* write it back and re-read */
2322                 start = d;
2323                 while (d != read_disk) {
2324                         if (d==0)
2325                                 d = conf->raid_disks * 2;
2326                         d--;
2327                         rcu_read_lock();
2328                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2329                         if (rdev &&
2330                             !test_bit(Faulty, &rdev->flags)) {
2331                                 atomic_inc(&rdev->nr_pending);
2332                                 rcu_read_unlock();
2333                                 r1_sync_page_io(rdev, sect, s,
2334                                                 conf->tmppage, WRITE);
2335                                 rdev_dec_pending(rdev, mddev);
2336                         } else
2337                                 rcu_read_unlock();
2338                 }
2339                 d = start;
2340                 while (d != read_disk) {
2341                         char b[BDEVNAME_SIZE];
2342                         if (d==0)
2343                                 d = conf->raid_disks * 2;
2344                         d--;
2345                         rcu_read_lock();
2346                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2347                         if (rdev &&
2348                             !test_bit(Faulty, &rdev->flags)) {
2349                                 atomic_inc(&rdev->nr_pending);
2350                                 rcu_read_unlock();
2351                                 if (r1_sync_page_io(rdev, sect, s,
2352                                                     conf->tmppage, READ)) {
2353                                         atomic_add(s, &rdev->corrected_errors);
2354                                         pr_info("md/raid1:%s: read error corrected (%d sectors at %llu on %s)\n",
2355                                                 mdname(mddev), s,
2356                                                 (unsigned long long)(sect +
2357                                                                      rdev->data_offset),
2358                                                 bdevname(rdev->bdev, b));
2359                                 }
2360                                 rdev_dec_pending(rdev, mddev);
2361                         } else
2362                                 rcu_read_unlock();
2363                 }
2364                 sectors -= s;
2365                 sect += s;
2366         }
2367 }
2368
2369 static int narrow_write_error(struct r1bio *r1_bio, int i)
2370 {
2371         struct mddev *mddev = r1_bio->mddev;
2372         struct r1conf *conf = mddev->private;
2373         struct md_rdev *rdev = conf->mirrors[i].rdev;
2374
2375         /* bio has the data to be written to device 'i' where
2376          * we just recently had a write error.
2377          * We repeatedly clone the bio and trim down to one block,
2378          * then try the write.  Where the write fails we record
2379          * a bad block.
2380          * It is conceivable that the bio doesn't exactly align with
2381          * blocks.  We must handle this somehow.
2382          *
2383          * We currently own a reference on the rdev.
2384          */
2385
2386         int block_sectors;
2387         sector_t sector;
2388         int sectors;
2389         int sect_to_write = r1_bio->sectors;
2390         int ok = 1;
2391
2392         if (rdev->badblocks.shift < 0)
2393                 return 0;
2394
2395         block_sectors = roundup(1 << rdev->badblocks.shift,
2396                                 bdev_logical_block_size(rdev->bdev) >> 9);
2397         sector = r1_bio->sector;
2398         sectors = ((sector + block_sectors)
2399                    & ~(sector_t)(block_sectors - 1))
2400                 - sector;
2401
2402         while (sect_to_write) {
2403                 struct bio *wbio;
2404                 if (sectors > sect_to_write)
2405                         sectors = sect_to_write;
2406                 /* Write at 'sector' for 'sectors'*/
2407
2408                 if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
2409                         wbio = bio_alloc_clone(rdev->bdev,
2410                                                r1_bio->behind_master_bio,
2411                                                GFP_NOIO, &mddev->bio_set);
2412                 } else {
2413                         wbio = bio_alloc_clone(rdev->bdev, r1_bio->master_bio,
2414                                                GFP_NOIO, &mddev->bio_set);
2415                 }
2416
2417                 bio_set_op_attrs(wbio, REQ_OP_WRITE, 0);
2418                 wbio->bi_iter.bi_sector = r1_bio->sector;
2419                 wbio->bi_iter.bi_size = r1_bio->sectors << 9;
2420
2421                 bio_trim(wbio, sector - r1_bio->sector, sectors);
2422                 wbio->bi_iter.bi_sector += rdev->data_offset;
2423
2424                 if (submit_bio_wait(wbio) < 0)
2425                         /* failure! */
2426                         ok = rdev_set_badblocks(rdev, sector,
2427                                                 sectors, 0)
2428                                 && ok;
2429
2430                 bio_put(wbio);
2431                 sect_to_write -= sectors;
2432                 sector += sectors;
2433                 sectors = block_sectors;
2434         }
2435         return ok;
2436 }
2437
2438 static void handle_sync_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2439 {
2440         int m;
2441         int s = r1_bio->sectors;
2442         for (m = 0; m < conf->raid_disks * 2 ; m++) {
2443                 struct md_rdev *rdev = conf->mirrors[m].rdev;
2444                 struct bio *bio = r1_bio->bios[m];
2445                 if (bio->bi_end_io == NULL)
2446                         continue;
2447                 if (!bio->bi_status &&
2448                     test_bit(R1BIO_MadeGood, &r1_bio->state)) {
2449                         rdev_clear_badblocks(rdev, r1_bio->sector, s, 0);
2450                 }
2451                 if (bio->bi_status &&
2452                     test_bit(R1BIO_WriteError, &r1_bio->state)) {
2453                         if (!rdev_set_badblocks(rdev, r1_bio->sector, s, 0))
2454                                 md_error(conf->mddev, rdev);
2455                 }
2456         }
2457         put_buf(r1_bio);
2458         md_done_sync(conf->mddev, s, 1);
2459 }
2460
2461 static void handle_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2462 {
2463         int m, idx;
2464         bool fail = false;
2465
2466         for (m = 0; m < conf->raid_disks * 2 ; m++)
2467                 if (r1_bio->bios[m] == IO_MADE_GOOD) {
2468                         struct md_rdev *rdev = conf->mirrors[m].rdev;
2469                         rdev_clear_badblocks(rdev,
2470                                              r1_bio->sector,
2471                                              r1_bio->sectors, 0);
2472                         rdev_dec_pending(rdev, conf->mddev);
2473                 } else if (r1_bio->bios[m] != NULL) {
2474                         /* This drive got a write error.  We need to
2475                          * narrow down and record precise write
2476                          * errors.
2477                          */
2478                         fail = true;
2479                         if (!narrow_write_error(r1_bio, m)) {
2480                                 md_error(conf->mddev,
2481                                          conf->mirrors[m].rdev);
2482                                 /* an I/O failed, we can't clear the bitmap */
2483                                 set_bit(R1BIO_Degraded, &r1_bio->state);
2484                         }
2485                         rdev_dec_pending(conf->mirrors[m].rdev,
2486                                          conf->mddev);
2487                 }
2488         if (fail) {
2489                 spin_lock_irq(&conf->device_lock);
2490                 list_add(&r1_bio->retry_list, &conf->bio_end_io_list);
2491                 idx = sector_to_idx(r1_bio->sector);
2492                 atomic_inc(&conf->nr_queued[idx]);
2493                 spin_unlock_irq(&conf->device_lock);
2494                 /*
2495                  * In case freeze_array() is waiting for condition
2496                  * get_unqueued_pending() == extra to be true.
2497                  */
2498                 wake_up(&conf->wait_barrier);
2499                 md_wakeup_thread(conf->mddev->thread);
2500         } else {
2501                 if (test_bit(R1BIO_WriteError, &r1_bio->state))
2502                         close_write(r1_bio);
2503                 raid_end_bio_io(r1_bio);
2504         }
2505 }
2506
2507 static void handle_read_error(struct r1conf *conf, struct r1bio *r1_bio)
2508 {
2509         struct mddev *mddev = conf->mddev;
2510         struct bio *bio;
2511         struct md_rdev *rdev;
2512
2513         clear_bit(R1BIO_ReadError, &r1_bio->state);
2514         /* we got a read error. Maybe the drive is bad.  Maybe just
2515          * the block and we can fix it.
2516          * We freeze all other IO, and try reading the block from
2517          * other devices.  When we find one, we re-write
2518          * and check it that fixes the read error.
2519          * This is all done synchronously while the array is
2520          * frozen
2521          */
2522
2523         bio = r1_bio->bios[r1_bio->read_disk];
2524         bio_put(bio);
2525         r1_bio->bios[r1_bio->read_disk] = NULL;
2526
2527         rdev = conf->mirrors[r1_bio->read_disk].rdev;
2528         if (mddev->ro == 0
2529             && !test_bit(FailFast, &rdev->flags)) {
2530                 freeze_array(conf, 1);
2531                 fix_read_error(conf, r1_bio->read_disk,
2532                                r1_bio->sector, r1_bio->sectors);
2533                 unfreeze_array(conf);
2534         } else if (mddev->ro == 0 && test_bit(FailFast, &rdev->flags)) {
2535                 md_error(mddev, rdev);
2536         } else {
2537                 r1_bio->bios[r1_bio->read_disk] = IO_BLOCKED;
2538         }
2539
2540         rdev_dec_pending(rdev, conf->mddev);
2541         allow_barrier(conf, r1_bio->sector);
2542         bio = r1_bio->master_bio;
2543
2544         /* Reuse the old r1_bio so that the IO_BLOCKED settings are preserved */
2545         r1_bio->state = 0;
2546         raid1_read_request(mddev, bio, r1_bio->sectors, r1_bio);
2547 }
2548
2549 static void raid1d(struct md_thread *thread)
2550 {
2551         struct mddev *mddev = thread->mddev;
2552         struct r1bio *r1_bio;
2553         unsigned long flags;
2554         struct r1conf *conf = mddev->private;
2555         struct list_head *head = &conf->retry_list;
2556         struct blk_plug plug;
2557         int idx;
2558
2559         md_check_recovery(mddev);
2560
2561         if (!list_empty_careful(&conf->bio_end_io_list) &&
2562             !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
2563                 LIST_HEAD(tmp);
2564                 spin_lock_irqsave(&conf->device_lock, flags);
2565                 if (!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags))
2566                         list_splice_init(&conf->bio_end_io_list, &tmp);
2567                 spin_unlock_irqrestore(&conf->device_lock, flags);
2568                 while (!list_empty(&tmp)) {
2569                         r1_bio = list_first_entry(&tmp, struct r1bio,
2570                                                   retry_list);
2571                         list_del(&r1_bio->retry_list);
2572                         idx = sector_to_idx(r1_bio->sector);
2573                         atomic_dec(&conf->nr_queued[idx]);
2574                         if (mddev->degraded)
2575                                 set_bit(R1BIO_Degraded, &r1_bio->state);
2576                         if (test_bit(R1BIO_WriteError, &r1_bio->state))
2577                                 close_write(r1_bio);
2578                         raid_end_bio_io(r1_bio);
2579                 }
2580         }
2581
2582         blk_start_plug(&plug);
2583         for (;;) {
2584
2585                 flush_pending_writes(conf);
2586
2587                 spin_lock_irqsave(&conf->device_lock, flags);
2588                 if (list_empty(head)) {
2589                         spin_unlock_irqrestore(&conf->device_lock, flags);
2590                         break;
2591                 }
2592                 r1_bio = list_entry(head->prev, struct r1bio, retry_list);
2593                 list_del(head->prev);
2594                 idx = sector_to_idx(r1_bio->sector);
2595                 atomic_dec(&conf->nr_queued[idx]);
2596                 spin_unlock_irqrestore(&conf->device_lock, flags);
2597
2598                 mddev = r1_bio->mddev;
2599                 conf = mddev->private;
2600                 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
2601                         if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2602                             test_bit(R1BIO_WriteError, &r1_bio->state))
2603                                 handle_sync_write_finished(conf, r1_bio);
2604                         else
2605                                 sync_request_write(mddev, r1_bio);
2606                 } else if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2607                            test_bit(R1BIO_WriteError, &r1_bio->state))
2608                         handle_write_finished(conf, r1_bio);
2609                 else if (test_bit(R1BIO_ReadError, &r1_bio->state))
2610                         handle_read_error(conf, r1_bio);
2611                 else
2612                         WARN_ON_ONCE(1);
2613
2614                 cond_resched();
2615                 if (mddev->sb_flags & ~(1<<MD_SB_CHANGE_PENDING))
2616                         md_check_recovery(mddev);
2617         }
2618         blk_finish_plug(&plug);
2619 }
2620
2621 static int init_resync(struct r1conf *conf)
2622 {
2623         int buffs;
2624
2625         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
2626         BUG_ON(mempool_initialized(&conf->r1buf_pool));
2627
2628         return mempool_init(&conf->r1buf_pool, buffs, r1buf_pool_alloc,
2629                             r1buf_pool_free, conf->poolinfo);
2630 }
2631
2632 static struct r1bio *raid1_alloc_init_r1buf(struct r1conf *conf)
2633 {
2634         struct r1bio *r1bio = mempool_alloc(&conf->r1buf_pool, GFP_NOIO);
2635         struct resync_pages *rps;
2636         struct bio *bio;
2637         int i;
2638
2639         for (i = conf->poolinfo->raid_disks; i--; ) {
2640                 bio = r1bio->bios[i];
2641                 rps = bio->bi_private;
2642                 bio_reset(bio, NULL, 0);
2643                 bio->bi_private = rps;
2644         }
2645         r1bio->master_bio = NULL;
2646         return r1bio;
2647 }
2648
2649 /*
2650  * perform a "sync" on one "block"
2651  *
2652  * We need to make sure that no normal I/O request - particularly write
2653  * requests - conflict with active sync requests.
2654  *
2655  * This is achieved by tracking pending requests and a 'barrier' concept
2656  * that can be installed to exclude normal IO requests.
2657  */
2658
2659 static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr,
2660                                    int *skipped)
2661 {
2662         struct r1conf *conf = mddev->private;
2663         struct r1bio *r1_bio;
2664         struct bio *bio;
2665         sector_t max_sector, nr_sectors;
2666         int disk = -1;
2667         int i;
2668         int wonly = -1;
2669         int write_targets = 0, read_targets = 0;
2670         sector_t sync_blocks;
2671         int still_degraded = 0;
2672         int good_sectors = RESYNC_SECTORS;
2673         int min_bad = 0; /* number of sectors that are bad in all devices */
2674         int idx = sector_to_idx(sector_nr);
2675         int page_idx = 0;
2676
2677         if (!mempool_initialized(&conf->r1buf_pool))
2678                 if (init_resync(conf))
2679                         return 0;
2680
2681         max_sector = mddev->dev_sectors;
2682         if (sector_nr >= max_sector) {
2683                 /* If we aborted, we need to abort the
2684                  * sync on the 'current' bitmap chunk (there will
2685                  * only be one in raid1 resync.
2686                  * We can find the current addess in mddev->curr_resync
2687                  */
2688                 if (mddev->curr_resync < max_sector) /* aborted */
2689                         md_bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
2690                                            &sync_blocks, 1);
2691                 else /* completed sync */
2692                         conf->fullsync = 0;
2693
2694                 md_bitmap_close_sync(mddev->bitmap);
2695                 close_sync(conf);
2696
2697                 if (mddev_is_clustered(mddev)) {
2698                         conf->cluster_sync_low = 0;
2699                         conf->cluster_sync_high = 0;
2700                 }
2701                 return 0;
2702         }
2703
2704         if (mddev->bitmap == NULL &&
2705             mddev->recovery_cp == MaxSector &&
2706             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
2707             conf->fullsync == 0) {
2708                 *skipped = 1;
2709                 return max_sector - sector_nr;
2710         }
2711         /* before building a request, check if we can skip these blocks..
2712          * This call the bitmap_start_sync doesn't actually record anything
2713          */
2714         if (!md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
2715             !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2716                 /* We can skip this block, and probably several more */
2717                 *skipped = 1;
2718                 return sync_blocks;
2719         }
2720
2721         /*
2722          * If there is non-resync activity waiting for a turn, then let it
2723          * though before starting on this new sync request.
2724          */
2725         if (atomic_read(&conf->nr_waiting[idx]))
2726                 schedule_timeout_uninterruptible(1);
2727
2728         /* we are incrementing sector_nr below. To be safe, we check against
2729          * sector_nr + two times RESYNC_SECTORS
2730          */
2731
2732         md_bitmap_cond_end_sync(mddev->bitmap, sector_nr,
2733                 mddev_is_clustered(mddev) && (sector_nr + 2 * RESYNC_SECTORS > conf->cluster_sync_high));
2734
2735
2736         if (raise_barrier(conf, sector_nr))
2737                 return 0;
2738
2739         r1_bio = raid1_alloc_init_r1buf(conf);
2740
2741         rcu_read_lock();
2742         /*
2743          * If we get a correctably read error during resync or recovery,
2744          * we might want to read from a different device.  So we
2745          * flag all drives that could conceivably be read from for READ,
2746          * and any others (which will be non-In_sync devices) for WRITE.
2747          * If a read fails, we try reading from something else for which READ
2748          * is OK.
2749          */
2750
2751         r1_bio->mddev = mddev;
2752         r1_bio->sector = sector_nr;
2753         r1_bio->state = 0;
2754         set_bit(R1BIO_IsSync, &r1_bio->state);
2755         /* make sure good_sectors won't go across barrier unit boundary */
2756         good_sectors = align_to_barrier_unit_end(sector_nr, good_sectors);
2757
2758         for (i = 0; i < conf->raid_disks * 2; i++) {
2759                 struct md_rdev *rdev;
2760                 bio = r1_bio->bios[i];
2761
2762                 rdev = rcu_dereference(conf->mirrors[i].rdev);
2763                 if (rdev == NULL ||
2764                     test_bit(Faulty, &rdev->flags)) {
2765                         if (i < conf->raid_disks)
2766                                 still_degraded = 1;
2767                 } else if (!test_bit(In_sync, &rdev->flags)) {
2768                         bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
2769                         bio->bi_end_io = end_sync_write;
2770                         write_targets ++;
2771                 } else {
2772                         /* may need to read from here */
2773                         sector_t first_bad = MaxSector;
2774                         int bad_sectors;
2775
2776                         if (is_badblock(rdev, sector_nr, good_sectors,
2777                                         &first_bad, &bad_sectors)) {
2778                                 if (first_bad > sector_nr)
2779                                         good_sectors = first_bad - sector_nr;
2780                                 else {
2781                                         bad_sectors -= (sector_nr - first_bad);
2782                                         if (min_bad == 0 ||
2783                                             min_bad > bad_sectors)
2784                                                 min_bad = bad_sectors;
2785                                 }
2786                         }
2787                         if (sector_nr < first_bad) {
2788                                 if (test_bit(WriteMostly, &rdev->flags)) {
2789                                         if (wonly < 0)
2790                                                 wonly = i;
2791                                 } else {
2792                                         if (disk < 0)
2793                                                 disk = i;
2794                                 }
2795                                 bio_set_op_attrs(bio, REQ_OP_READ, 0);
2796                                 bio->bi_end_io = end_sync_read;
2797                                 read_targets++;
2798                         } else if (!test_bit(WriteErrorSeen, &rdev->flags) &&
2799                                 test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
2800                                 !test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) {
2801                                 /*
2802                                  * The device is suitable for reading (InSync),
2803                                  * but has bad block(s) here. Let's try to correct them,
2804                                  * if we are doing resync or repair. Otherwise, leave
2805                                  * this device alone for this sync request.
2806                                  */
2807                                 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
2808                                 bio->bi_end_io = end_sync_write;
2809                                 write_targets++;
2810                         }
2811                 }
2812                 if (rdev && bio->bi_end_io) {
2813                         atomic_inc(&rdev->nr_pending);
2814                         bio->bi_iter.bi_sector = sector_nr + rdev->data_offset;
2815                         bio_set_dev(bio, rdev->bdev);
2816                         if (test_bit(FailFast, &rdev->flags))
2817                                 bio->bi_opf |= MD_FAILFAST;
2818                 }
2819         }
2820         rcu_read_unlock();
2821         if (disk < 0)
2822                 disk = wonly;
2823         r1_bio->read_disk = disk;
2824
2825         if (read_targets == 0 && min_bad > 0) {
2826                 /* These sectors are bad on all InSync devices, so we
2827                  * need to mark them bad on all write targets
2828                  */
2829                 int ok = 1;
2830                 for (i = 0 ; i < conf->raid_disks * 2 ; i++)
2831                         if (r1_bio->bios[i]->bi_end_io == end_sync_write) {
2832                                 struct md_rdev *rdev = conf->mirrors[i].rdev;
2833                                 ok = rdev_set_badblocks(rdev, sector_nr,
2834                                                         min_bad, 0
2835                                         ) && ok;
2836                         }
2837                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
2838                 *skipped = 1;
2839                 put_buf(r1_bio);
2840
2841                 if (!ok) {
2842                         /* Cannot record the badblocks, so need to
2843                          * abort the resync.
2844                          * If there are multiple read targets, could just
2845                          * fail the really bad ones ???
2846                          */
2847                         conf->recovery_disabled = mddev->recovery_disabled;
2848                         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2849                         return 0;
2850                 } else
2851                         return min_bad;
2852
2853         }
2854         if (min_bad > 0 && min_bad < good_sectors) {
2855                 /* only resync enough to reach the next bad->good
2856                  * transition */
2857                 good_sectors = min_bad;
2858         }
2859
2860         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
2861                 /* extra read targets are also write targets */
2862                 write_targets += read_targets-1;
2863
2864         if (write_targets == 0 || read_targets == 0) {
2865                 /* There is nowhere to write, so all non-sync
2866                  * drives must be failed - so we are finished
2867                  */
2868                 sector_t rv;
2869                 if (min_bad > 0)
2870                         max_sector = sector_nr + min_bad;
2871                 rv = max_sector - sector_nr;
2872                 *skipped = 1;
2873                 put_buf(r1_bio);
2874                 return rv;
2875         }
2876
2877         if (max_sector > mddev->resync_max)
2878                 max_sector = mddev->resync_max; /* Don't do IO beyond here */
2879         if (max_sector > sector_nr + good_sectors)
2880                 max_sector = sector_nr + good_sectors;
2881         nr_sectors = 0;
2882         sync_blocks = 0;
2883         do {
2884                 struct page *page;
2885                 int len = PAGE_SIZE;
2886                 if (sector_nr + (len>>9) > max_sector)
2887                         len = (max_sector - sector_nr) << 9;
2888                 if (len == 0)
2889                         break;
2890                 if (sync_blocks == 0) {
2891                         if (!md_bitmap_start_sync(mddev->bitmap, sector_nr,
2892                                                   &sync_blocks, still_degraded) &&
2893                             !conf->fullsync &&
2894                             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2895                                 break;
2896                         if ((len >> 9) > sync_blocks)
2897                                 len = sync_blocks<<9;
2898                 }
2899
2900                 for (i = 0 ; i < conf->raid_disks * 2; i++) {
2901                         struct resync_pages *rp;
2902
2903                         bio = r1_bio->bios[i];
2904                         rp = get_resync_pages(bio);
2905                         if (bio->bi_end_io) {
2906                                 page = resync_fetch_page(rp, page_idx);
2907
2908                                 /*
2909                                  * won't fail because the vec table is big
2910                                  * enough to hold all these pages
2911                                  */
2912                                 bio_add_page(bio, page, len, 0);
2913                         }
2914                 }
2915                 nr_sectors += len>>9;
2916                 sector_nr += len>>9;
2917                 sync_blocks -= (len>>9);
2918         } while (++page_idx < RESYNC_PAGES);
2919
2920         r1_bio->sectors = nr_sectors;
2921
2922         if (mddev_is_clustered(mddev) &&
2923                         conf->cluster_sync_high < sector_nr + nr_sectors) {
2924                 conf->cluster_sync_low = mddev->curr_resync_completed;
2925                 conf->cluster_sync_high = conf->cluster_sync_low + CLUSTER_RESYNC_WINDOW_SECTORS;
2926                 /* Send resync message */
2927                 md_cluster_ops->resync_info_update(mddev,
2928                                 conf->cluster_sync_low,
2929                                 conf->cluster_sync_high);
2930         }
2931
2932         /* For a user-requested sync, we read all readable devices and do a
2933          * compare
2934          */
2935         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2936                 atomic_set(&r1_bio->remaining, read_targets);
2937                 for (i = 0; i < conf->raid_disks * 2 && read_targets; i++) {
2938                         bio = r1_bio->bios[i];
2939                         if (bio->bi_end_io == end_sync_read) {
2940                                 read_targets--;
2941                                 md_sync_acct_bio(bio, nr_sectors);
2942                                 if (read_targets == 1)
2943                                         bio->bi_opf &= ~MD_FAILFAST;
2944                                 submit_bio_noacct(bio);
2945                         }
2946                 }
2947         } else {
2948                 atomic_set(&r1_bio->remaining, 1);
2949                 bio = r1_bio->bios[r1_bio->read_disk];
2950                 md_sync_acct_bio(bio, nr_sectors);
2951                 if (read_targets == 1)
2952                         bio->bi_opf &= ~MD_FAILFAST;
2953                 submit_bio_noacct(bio);
2954         }
2955         return nr_sectors;
2956 }
2957
2958 static sector_t raid1_size(struct mddev *mddev, sector_t sectors, int raid_disks)
2959 {
2960         if (sectors)
2961                 return sectors;
2962
2963         return mddev->dev_sectors;
2964 }
2965
2966 static struct r1conf *setup_conf(struct mddev *mddev)
2967 {
2968         struct r1conf *conf;
2969         int i;
2970         struct raid1_info *disk;
2971         struct md_rdev *rdev;
2972         int err = -ENOMEM;
2973
2974         conf = kzalloc(sizeof(struct r1conf), GFP_KERNEL);
2975         if (!conf)
2976                 goto abort;
2977
2978         conf->nr_pending = kcalloc(BARRIER_BUCKETS_NR,
2979                                    sizeof(atomic_t), GFP_KERNEL);
2980         if (!conf->nr_pending)
2981                 goto abort;
2982
2983         conf->nr_waiting = kcalloc(BARRIER_BUCKETS_NR,
2984                                    sizeof(atomic_t), GFP_KERNEL);
2985         if (!conf->nr_waiting)
2986                 goto abort;
2987
2988         conf->nr_queued = kcalloc(BARRIER_BUCKETS_NR,
2989                                   sizeof(atomic_t), GFP_KERNEL);
2990         if (!conf->nr_queued)
2991                 goto abort;
2992
2993         conf->barrier = kcalloc(BARRIER_BUCKETS_NR,
2994                                 sizeof(atomic_t), GFP_KERNEL);
2995         if (!conf->barrier)
2996                 goto abort;
2997
2998         conf->mirrors = kzalloc(array3_size(sizeof(struct raid1_info),
2999                                             mddev->raid_disks, 2),
3000                                 GFP_KERNEL);
3001         if (!conf->mirrors)
3002                 goto abort;
3003
3004         conf->tmppage = alloc_page(GFP_KERNEL);
3005         if (!conf->tmppage)
3006                 goto abort;
3007
3008         conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
3009         if (!conf->poolinfo)
3010                 goto abort;
3011         conf->poolinfo->raid_disks = mddev->raid_disks * 2;
3012         err = mempool_init(&conf->r1bio_pool, NR_RAID_BIOS, r1bio_pool_alloc,
3013                            rbio_pool_free, conf->poolinfo);
3014         if (err)
3015                 goto abort;
3016
3017         err = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
3018         if (err)
3019                 goto abort;
3020
3021         conf->poolinfo->mddev = mddev;
3022
3023         err = -EINVAL;
3024         spin_lock_init(&conf->device_lock);
3025         rdev_for_each(rdev, mddev) {
3026                 int disk_idx = rdev->raid_disk;
3027                 if (disk_idx >= mddev->raid_disks
3028                     || disk_idx < 0)
3029                         continue;
3030                 if (test_bit(Replacement, &rdev->flags))
3031                         disk = conf->mirrors + mddev->raid_disks + disk_idx;
3032                 else
3033                         disk = conf->mirrors + disk_idx;
3034
3035                 if (disk->rdev)
3036                         goto abort;
3037                 disk->rdev = rdev;
3038                 disk->head_position = 0;
3039                 disk->seq_start = MaxSector;
3040         }
3041         conf->raid_disks = mddev->raid_disks;
3042         conf->mddev = mddev;
3043         INIT_LIST_HEAD(&conf->retry_list);
3044         INIT_LIST_HEAD(&conf->bio_end_io_list);
3045
3046         spin_lock_init(&conf->resync_lock);
3047         init_waitqueue_head(&conf->wait_barrier);
3048
3049         bio_list_init(&conf->pending_bio_list);
3050         conf->recovery_disabled = mddev->recovery_disabled - 1;
3051
3052         err = -EIO;
3053         for (i = 0; i < conf->raid_disks * 2; i++) {
3054
3055                 disk = conf->mirrors + i;
3056
3057                 if (i < conf->raid_disks &&
3058                     disk[conf->raid_disks].rdev) {
3059                         /* This slot has a replacement. */
3060                         if (!disk->rdev) {
3061                                 /* No original, just make the replacement
3062                                  * a recovering spare
3063                                  */
3064                                 disk->rdev =
3065                                         disk[conf->raid_disks].rdev;
3066                                 disk[conf->raid_disks].rdev = NULL;
3067                         } else if (!test_bit(In_sync, &disk->rdev->flags))
3068                                 /* Original is not in_sync - bad */
3069                                 goto abort;
3070                 }
3071
3072                 if (!disk->rdev ||
3073                     !test_bit(In_sync, &disk->rdev->flags)) {
3074                         disk->head_position = 0;
3075                         if (disk->rdev &&
3076                             (disk->rdev->saved_raid_disk < 0))
3077                                 conf->fullsync = 1;
3078                 }
3079         }
3080
3081         err = -ENOMEM;
3082         conf->thread = md_register_thread(raid1d, mddev, "raid1");
3083         if (!conf->thread)
3084                 goto abort;
3085
3086         return conf;
3087
3088  abort:
3089         if (conf) {
3090                 mempool_exit(&conf->r1bio_pool);
3091                 kfree(conf->mirrors);
3092                 safe_put_page(conf->tmppage);
3093                 kfree(conf->poolinfo);
3094                 kfree(conf->nr_pending);
3095                 kfree(conf->nr_waiting);
3096                 kfree(conf->nr_queued);
3097                 kfree(conf->barrier);
3098                 bioset_exit(&conf->bio_split);
3099                 kfree(conf);
3100         }
3101         return ERR_PTR(err);
3102 }
3103
3104 static void raid1_free(struct mddev *mddev, void *priv);
3105 static int raid1_run(struct mddev *mddev)
3106 {
3107         struct r1conf *conf;
3108         int i;
3109         struct md_rdev *rdev;
3110         int ret;
3111         bool discard_supported = false;
3112
3113         if (mddev->level != 1) {
3114                 pr_warn("md/raid1:%s: raid level not set to mirroring (%d)\n",
3115                         mdname(mddev), mddev->level);
3116                 return -EIO;
3117         }
3118         if (mddev->reshape_position != MaxSector) {
3119                 pr_warn("md/raid1:%s: reshape_position set but not supported\n",
3120                         mdname(mddev));
3121                 return -EIO;
3122         }
3123         if (mddev_init_writes_pending(mddev) < 0)
3124                 return -ENOMEM;
3125         /*
3126          * copy the already verified devices into our private RAID1
3127          * bookkeeping area. [whatever we allocate in run(),
3128          * should be freed in raid1_free()]
3129          */
3130         if (mddev->private == NULL)
3131                 conf = setup_conf(mddev);
3132         else
3133                 conf = mddev->private;
3134
3135         if (IS_ERR(conf))
3136                 return PTR_ERR(conf);
3137
3138         if (mddev->queue)
3139                 blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
3140
3141         rdev_for_each(rdev, mddev) {
3142                 if (!mddev->gendisk)
3143                         continue;
3144                 disk_stack_limits(mddev->gendisk, rdev->bdev,
3145                                   rdev->data_offset << 9);
3146                 if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
3147                         discard_supported = true;
3148         }
3149
3150         mddev->degraded = 0;
3151         for (i = 0; i < conf->raid_disks; i++)
3152                 if (conf->mirrors[i].rdev == NULL ||
3153                     !test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
3154                     test_bit(Faulty, &conf->mirrors[i].rdev->flags))
3155                         mddev->degraded++;
3156         /*
3157          * RAID1 needs at least one disk in active
3158          */
3159         if (conf->raid_disks - mddev->degraded < 1) {
3160                 ret = -EINVAL;
3161                 goto abort;
3162         }
3163
3164         if (conf->raid_disks - mddev->degraded == 1)
3165                 mddev->recovery_cp = MaxSector;
3166
3167         if (mddev->recovery_cp != MaxSector)
3168                 pr_info("md/raid1:%s: not clean -- starting background reconstruction\n",
3169                         mdname(mddev));
3170         pr_info("md/raid1:%s: active with %d out of %d mirrors\n",
3171                 mdname(mddev), mddev->raid_disks - mddev->degraded,
3172                 mddev->raid_disks);
3173
3174         /*
3175          * Ok, everything is just fine now
3176          */
3177         mddev->thread = conf->thread;
3178         conf->thread = NULL;
3179         mddev->private = conf;
3180         set_bit(MD_FAILFAST_SUPPORTED, &mddev->flags);
3181
3182         md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
3183
3184         if (mddev->queue) {
3185                 if (discard_supported)
3186                         blk_queue_flag_set(QUEUE_FLAG_DISCARD,
3187                                                 mddev->queue);
3188                 else
3189                         blk_queue_flag_clear(QUEUE_FLAG_DISCARD,
3190                                                   mddev->queue);
3191         }
3192
3193         ret = md_integrity_register(mddev);
3194         if (ret) {
3195                 md_unregister_thread(&mddev->thread);
3196                 goto abort;
3197         }
3198         return 0;
3199
3200 abort:
3201         raid1_free(mddev, conf);
3202         return ret;
3203 }
3204
3205 static void raid1_free(struct mddev *mddev, void *priv)
3206 {
3207         struct r1conf *conf = priv;
3208
3209         mempool_exit(&conf->r1bio_pool);
3210         kfree(conf->mirrors);
3211         safe_put_page(conf->tmppage);
3212         kfree(conf->poolinfo);
3213         kfree(conf->nr_pending);
3214         kfree(conf->nr_waiting);
3215         kfree(conf->nr_queued);
3216         kfree(conf->barrier);
3217         bioset_exit(&conf->bio_split);
3218         kfree(conf);
3219 }
3220
3221 static int raid1_resize(struct mddev *mddev, sector_t sectors)
3222 {
3223         /* no resync is happening, and there is enough space
3224          * on all devices, so we can resize.
3225          * We need to make sure resync covers any new space.
3226          * If the array is shrinking we should possibly wait until
3227          * any io in the removed space completes, but it hardly seems
3228          * worth it.
3229          */
3230         sector_t newsize = raid1_size(mddev, sectors, 0);
3231         if (mddev->external_size &&
3232             mddev->array_sectors > newsize)
3233                 return -EINVAL;
3234         if (mddev->bitmap) {
3235                 int ret = md_bitmap_resize(mddev->bitmap, newsize, 0, 0);
3236                 if (ret)
3237                         return ret;
3238         }
3239         md_set_array_sectors(mddev, newsize);
3240         if (sectors > mddev->dev_sectors &&
3241             mddev->recovery_cp > mddev->dev_sectors) {
3242                 mddev->recovery_cp = mddev->dev_sectors;
3243                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3244         }
3245         mddev->dev_sectors = sectors;
3246         mddev->resync_max_sectors = sectors;
3247         return 0;
3248 }
3249
3250 static int raid1_reshape(struct mddev *mddev)
3251 {
3252         /* We need to:
3253          * 1/ resize the r1bio_pool
3254          * 2/ resize conf->mirrors
3255          *
3256          * We allocate a new r1bio_pool if we can.
3257          * Then raise a device barrier and wait until all IO stops.
3258          * Then resize conf->mirrors and swap in the new r1bio pool.
3259          *
3260          * At the same time, we "pack" the devices so that all the missing
3261          * devices have the higher raid_disk numbers.
3262          */
3263         mempool_t newpool, oldpool;
3264         struct pool_info *newpoolinfo;
3265         struct raid1_info *newmirrors;
3266         struct r1conf *conf = mddev->private;
3267         int cnt, raid_disks;
3268         unsigned long flags;
3269         int d, d2;
3270         int ret;
3271
3272         memset(&newpool, 0, sizeof(newpool));
3273         memset(&oldpool, 0, sizeof(oldpool));
3274
3275         /* Cannot change chunk_size, layout, or level */
3276         if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
3277             mddev->layout != mddev->new_layout ||
3278             mddev->level != mddev->new_level) {
3279                 mddev->new_chunk_sectors = mddev->chunk_sectors;
3280                 mddev->new_layout = mddev->layout;
3281                 mddev->new_level = mddev->level;
3282                 return -EINVAL;
3283         }
3284
3285         if (!mddev_is_clustered(mddev))
3286                 md_allow_write(mddev);
3287
3288         raid_disks = mddev->raid_disks + mddev->delta_disks;
3289
3290         if (raid_disks < conf->raid_disks) {
3291                 cnt=0;
3292                 for (d= 0; d < conf->raid_disks; d++)
3293                         if (conf->mirrors[d].rdev)
3294                                 cnt++;
3295                 if (cnt > raid_disks)
3296                         return -EBUSY;
3297         }
3298
3299         newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
3300         if (!newpoolinfo)
3301                 return -ENOMEM;
3302         newpoolinfo->mddev = mddev;
3303         newpoolinfo->raid_disks = raid_disks * 2;
3304
3305         ret = mempool_init(&newpool, NR_RAID_BIOS, r1bio_pool_alloc,
3306                            rbio_pool_free, newpoolinfo);
3307         if (ret) {
3308                 kfree(newpoolinfo);
3309                 return ret;
3310         }
3311         newmirrors = kzalloc(array3_size(sizeof(struct raid1_info),
3312                                          raid_disks, 2),
3313                              GFP_KERNEL);
3314         if (!newmirrors) {
3315                 kfree(newpoolinfo);
3316                 mempool_exit(&newpool);
3317                 return -ENOMEM;
3318         }
3319
3320         freeze_array(conf, 0);
3321
3322         /* ok, everything is stopped */
3323         oldpool = conf->r1bio_pool;
3324         conf->r1bio_pool = newpool;
3325
3326         for (d = d2 = 0; d < conf->raid_disks; d++) {
3327                 struct md_rdev *rdev = conf->mirrors[d].rdev;
3328                 if (rdev && rdev->raid_disk != d2) {
3329                         sysfs_unlink_rdev(mddev, rdev);
3330                         rdev->raid_disk = d2;
3331                         sysfs_unlink_rdev(mddev, rdev);
3332                         if (sysfs_link_rdev(mddev, rdev))
3333                                 pr_warn("md/raid1:%s: cannot register rd%d\n",
3334                                         mdname(mddev), rdev->raid_disk);
3335                 }
3336                 if (rdev)
3337                         newmirrors[d2++].rdev = rdev;
3338         }
3339         kfree(conf->mirrors);
3340         conf->mirrors = newmirrors;
3341         kfree(conf->poolinfo);
3342         conf->poolinfo = newpoolinfo;
3343
3344         spin_lock_irqsave(&conf->device_lock, flags);
3345         mddev->degraded += (raid_disks - conf->raid_disks);
3346         spin_unlock_irqrestore(&conf->device_lock, flags);
3347         conf->raid_disks = mddev->raid_disks = raid_disks;
3348         mddev->delta_disks = 0;
3349
3350         unfreeze_array(conf);
3351
3352         set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
3353         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3354         md_wakeup_thread(mddev->thread);
3355
3356         mempool_exit(&oldpool);
3357         return 0;
3358 }
3359
3360 static void raid1_quiesce(struct mddev *mddev, int quiesce)
3361 {
3362         struct r1conf *conf = mddev->private;
3363
3364         if (quiesce)
3365                 freeze_array(conf, 0);
3366         else
3367                 unfreeze_array(conf);
3368 }
3369
3370 static void *raid1_takeover(struct mddev *mddev)
3371 {
3372         /* raid1 can take over:
3373          *  raid5 with 2 devices, any layout or chunk size
3374          */
3375         if (mddev->level == 5 && mddev->raid_disks == 2) {
3376                 struct r1conf *conf;
3377                 mddev->new_level = 1;
3378                 mddev->new_layout = 0;
3379                 mddev->new_chunk_sectors = 0;
3380                 conf = setup_conf(mddev);
3381                 if (!IS_ERR(conf)) {
3382                         /* Array must appear to be quiesced */
3383                         conf->array_frozen = 1;
3384                         mddev_clear_unsupported_flags(mddev,
3385                                 UNSUPPORTED_MDDEV_FLAGS);
3386                 }
3387                 return conf;
3388         }
3389         return ERR_PTR(-EINVAL);
3390 }
3391
3392 static struct md_personality raid1_personality =
3393 {
3394         .name           = "raid1",
3395         .level          = 1,
3396         .owner          = THIS_MODULE,
3397         .make_request   = raid1_make_request,
3398         .run            = raid1_run,
3399         .free           = raid1_free,
3400         .status         = raid1_status,
3401         .error_handler  = raid1_error,
3402         .hot_add_disk   = raid1_add_disk,
3403         .hot_remove_disk= raid1_remove_disk,
3404         .spare_active   = raid1_spare_active,
3405         .sync_request   = raid1_sync_request,
3406         .resize         = raid1_resize,
3407         .size           = raid1_size,
3408         .check_reshape  = raid1_reshape,
3409         .quiesce        = raid1_quiesce,
3410         .takeover       = raid1_takeover,
3411 };
3412
3413 static int __init raid_init(void)
3414 {
3415         return register_md_personality(&raid1_personality);
3416 }
3417
3418 static void raid_exit(void)
3419 {
3420         unregister_md_personality(&raid1_personality);
3421 }
3422
3423 module_init(raid_init);
3424 module_exit(raid_exit);
3425 MODULE_LICENSE("GPL");
3426 MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
3427 MODULE_ALIAS("md-personality-3"); /* RAID1 */
3428 MODULE_ALIAS("md-raid1");
3429 MODULE_ALIAS("md-level-1");