drivers/md/raid1.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * raid1.c : Multiple Devices driver for Linux
   4  *
   5  * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat
   6  *
   7  * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman
   8  *
   9  * RAID-1 management functions.
  10  *
  11  * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000
  12  *
  13  * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
  14  * Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
  15  *
  16  * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support
  17  * bitmapped intelligence in resync:
  18  *
  19  *      - bitmap marked during normal i/o
  20  *      - bitmap used to skip nondirty blocks during sync
  21  *
  22  * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology:
  23  * - persistent bitmap code
  24  */
  25
  26 #include <linux/slab.h>
  27 #include <linux/delay.h>
  28 #include <linux/blkdev.h>
  29 #include <linux/module.h>
  30 #include <linux/seq_file.h>
  31 #include <linux/ratelimit.h>
  32 #include <linux/interval_tree_generic.h>
  33
  34 #include <trace/events/block.h>
  35
  36 #include "md.h"
  37 #include "raid1.h"
  38 #include "md-bitmap.h"
  39
  40 #define UNSUPPORTED_MDDEV_FLAGS         \
  41         ((1L << MD_HAS_JOURNAL) |       \
  42          (1L << MD_JOURNAL_CLEAN) |     \
  43          (1L << MD_HAS_PPL) |           \
  44          (1L << MD_HAS_MULTIPLE_PPLS))
  45
  46 static void allow_barrier(struct r1conf *conf, sector_t sector_nr);
  47 static void lower_barrier(struct r1conf *conf, sector_t sector_nr);
  48
  49 #define raid1_log(md, fmt, args...)                             \
  50         do { if ((md)->queue) blk_add_trace_msg((md)->queue, "raid1 " fmt, ##args); } while (0)
  51
  52 #include "raid1-10.c"
  53
  54 #define START(node) ((node)->start)
  55 #define LAST(node) ((node)->last)
  56 INTERVAL_TREE_DEFINE(struct serial_info, node, sector_t, _subtree_last,
  57                      START, LAST, static inline, raid1_rb);
  58
  59 static int check_and_add_serial(struct md_rdev *rdev, struct r1bio *r1_bio,
  60                                 struct serial_info *si, int idx)
  61 {
  62         unsigned long flags;
  63         int ret = 0;
  64         sector_t lo = r1_bio->sector;
  65         sector_t hi = lo + r1_bio->sectors;
  66         struct serial_in_rdev *serial = &rdev->serial[idx];
  67
  68         spin_lock_irqsave(&serial->serial_lock, flags);
  69         /* collision happened */
  70         if (raid1_rb_iter_first(&serial->serial_rb, lo, hi))
  71                 ret = -EBUSY;
  72         else {
  73                 si->start = lo;
  74                 si->last = hi;
  75                 raid1_rb_insert(si, &serial->serial_rb);
  76         }
  77         spin_unlock_irqrestore(&serial->serial_lock, flags);
  78
  79         return ret;
  80 }
  81
  82 static void wait_for_serialization(struct md_rdev *rdev, struct r1bio *r1_bio)
  83 {
  84         struct mddev *mddev = rdev->mddev;
  85         struct serial_info *si;
  86         int idx = sector_to_idx(r1_bio->sector);
  87         struct serial_in_rdev *serial = &rdev->serial[idx];
  88
  89         if (WARN_ON(!mddev->serial_info_pool))
  90                 return;
  91         si = mempool_alloc(mddev->serial_info_pool, GFP_NOIO);
  92         wait_event(serial->serial_io_wait,
  93                    check_and_add_serial(rdev, r1_bio, si, idx) == 0);
  94 }
  95
  96 static void remove_serial(struct md_rdev *rdev, sector_t lo, sector_t hi)
  97 {
  98         struct serial_info *si;
  99         unsigned long flags;
 100         int found = 0;
 101         struct mddev *mddev = rdev->mddev;
 102         int idx = sector_to_idx(lo);
 103         struct serial_in_rdev *serial = &rdev->serial[idx];
 104
 105         spin_lock_irqsave(&serial->serial_lock, flags);
 106         for (si = raid1_rb_iter_first(&serial->serial_rb, lo, hi);
 107              si; si = raid1_rb_iter_next(si, lo, hi)) {
 108                 if (si->start == lo && si->last == hi) {
 109                         raid1_rb_remove(si, &serial->serial_rb);
 110                         mempool_free(si, mddev->serial_info_pool);
 111                         found = 1;
 112                         break;
 113                 }
 114         }
 115         if (!found)
 116                 WARN(1, "The write IO is not recorded for serialization\n");
 117         spin_unlock_irqrestore(&serial->serial_lock, flags);
 118         wake_up(&serial->serial_io_wait);
 119 }
 120
 121 /*
 122  * for resync bio, r1bio pointer can be retrieved from the per-bio
 123  * 'struct resync_pages'.
 124  */
 125 static inline struct r1bio *get_resync_r1bio(struct bio *bio)
 126 {
 127         return get_resync_pages(bio)->raid_bio;
 128 }
 129
 130 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
 131 {
 132         struct pool_info *pi = data;
 133         int size = offsetof(struct r1bio, bios[pi->raid_disks]);
 134
 135         /* allocate a r1bio with room for raid_disks entries in the bios array */
 136         return kzalloc(size, gfp_flags);
 137 }
 138
 139 #define RESYNC_DEPTH 32
 140 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
 141 #define RESYNC_WINDOW (RESYNC_BLOCK_SIZE * RESYNC_DEPTH)
 142 #define RESYNC_WINDOW_SECTORS (RESYNC_WINDOW >> 9)
 143 #define CLUSTER_RESYNC_WINDOW (16 * RESYNC_WINDOW)
 144 #define CLUSTER_RESYNC_WINDOW_SECTORS (CLUSTER_RESYNC_WINDOW >> 9)
 145
 146 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
 147 {
 148         struct pool_info *pi = data;
 149         struct r1bio *r1_bio;
 150         struct bio *bio;
 151         int need_pages;
 152         int j;
 153         struct resync_pages *rps;
 154
 155         r1_bio = r1bio_pool_alloc(gfp_flags, pi);
 156         if (!r1_bio)
 157                 return NULL;
 158
 159         rps = kmalloc_array(pi->raid_disks, sizeof(struct resync_pages),
 160                             gfp_flags);
 161         if (!rps)
 162                 goto out_free_r1bio;
 163
 164         /*
 165          * Allocate bios : 1 for reading, n-1 for writing
 166          */
 167         for (j = pi->raid_disks ; j-- ; ) {
 168                 bio = bio_kmalloc(RESYNC_PAGES, gfp_flags);
 169                 if (!bio)
 170                         goto out_free_bio;
 171                 bio_init(bio, NULL, bio->bi_inline_vecs, RESYNC_PAGES, 0);
 172                 r1_bio->bios[j] = bio;
 173         }
 174         /*
 175          * Allocate RESYNC_PAGES data pages and attach them to
 176          * the first bio.
 177          * If this is a user-requested check/repair, allocate
 178          * RESYNC_PAGES for each bio.
 179          */
 180         if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
 181                 need_pages = pi->raid_disks;
 182         else
 183                 need_pages = 1;
 184         for (j = 0; j < pi->raid_disks; j++) {
 185                 struct resync_pages *rp = &rps[j];
 186
 187                 bio = r1_bio->bios[j];
 188
 189                 if (j < need_pages) {
 190                         if (resync_alloc_pages(rp, gfp_flags))
 191                                 goto out_free_pages;
 192                 } else {
 193                         memcpy(rp, &rps[0], sizeof(*rp));
 194                         resync_get_all_pages(rp);
 195                 }
 196
 197                 rp->raid_bio = r1_bio;
 198                 bio->bi_private = rp;
 199         }
 200
 201         r1_bio->master_bio = NULL;
 202
 203         return r1_bio;
 204
 205 out_free_pages:
 206         while (--j >= 0)
 207                 resync_free_pages(&rps[j]);
 208
 209 out_free_bio:
 210         while (++j < pi->raid_disks) {
 211                 bio_uninit(r1_bio->bios[j]);
 212                 kfree(r1_bio->bios[j]);
 213         }
 214         kfree(rps);
 215
 216 out_free_r1bio:
 217         rbio_pool_free(r1_bio, data);
 218         return NULL;
 219 }
 220
 221 static void r1buf_pool_free(void *__r1_bio, void *data)
 222 {
 223         struct pool_info *pi = data;
 224         int i;
 225         struct r1bio *r1bio = __r1_bio;
 226         struct resync_pages *rp = NULL;
 227
 228         for (i = pi->raid_disks; i--; ) {
 229                 rp = get_resync_pages(r1bio->bios[i]);
 230                 resync_free_pages(rp);
 231                 bio_uninit(r1bio->bios[i]);
 232                 kfree(r1bio->bios[i]);
 233         }
 234
 235         /* resync pages array stored in the 1st bio's .bi_private */
 236         kfree(rp);
 237
 238         rbio_pool_free(r1bio, data);
 239 }
 240
 241 static void put_all_bios(struct r1conf *conf, struct r1bio *r1_bio)
 242 {
 243         int i;
 244
 245         for (i = 0; i < conf->raid_disks * 2; i++) {
 246                 struct bio **bio = r1_bio->bios + i;
 247                 if (!BIO_SPECIAL(*bio))
 248                         bio_put(*bio);
 249                 *bio = NULL;
 250         }
 251 }
 252
 253 static void free_r1bio(struct r1bio *r1_bio)
 254 {
 255         struct r1conf *conf = r1_bio->mddev->private;
 256
 257         put_all_bios(conf, r1_bio);
 258         mempool_free(r1_bio, &conf->r1bio_pool);
 259 }
 260
 261 static void put_buf(struct r1bio *r1_bio)
 262 {
 263         struct r1conf *conf = r1_bio->mddev->private;
 264         sector_t sect = r1_bio->sector;
 265         int i;
 266
 267         for (i = 0; i < conf->raid_disks * 2; i++) {
 268                 struct bio *bio = r1_bio->bios[i];
 269                 if (bio->bi_end_io)
 270                         rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
 271         }
 272
 273         mempool_free(r1_bio, &conf->r1buf_pool);
 274
 275         lower_barrier(conf, sect);
 276 }
 277
 278 static void reschedule_retry(struct r1bio *r1_bio)
 279 {
 280         unsigned long flags;
 281         struct mddev *mddev = r1_bio->mddev;
 282         struct r1conf *conf = mddev->private;
 283         int idx;
 284
 285         idx = sector_to_idx(r1_bio->sector);
 286         spin_lock_irqsave(&conf->device_lock, flags);
 287         list_add(&r1_bio->retry_list, &conf->retry_list);
 288         atomic_inc(&conf->nr_queued[idx]);
 289         spin_unlock_irqrestore(&conf->device_lock, flags);
 290
 291         wake_up(&conf->wait_barrier);
 292         md_wakeup_thread(mddev->thread);
 293 }
 294
 295 /*
 296  * raid_end_bio_io() is called when we have finished servicing a mirrored
 297  * operation and are ready to return a success/failure code to the buffer
 298  * cache layer.
 299  */
 300 static void call_bio_endio(struct r1bio *r1_bio)
 301 {
 302         struct bio *bio = r1_bio->master_bio;
 303
 304         if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
 305                 bio->bi_status = BLK_STS_IOERR;
 306
 307         if (blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
 308                 bio_end_io_acct(bio, r1_bio->start_time);
 309         bio_endio(bio);
 310 }
 311
 312 static void raid_end_bio_io(struct r1bio *r1_bio)
 313 {
 314         struct bio *bio = r1_bio->master_bio;
 315         struct r1conf *conf = r1_bio->mddev->private;
 316
 317         /* if nobody has done the final endio yet, do it now */
 318         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 319                 pr_debug("raid1: sync end %s on sectors %llu-%llu\n",
 320                          (bio_data_dir(bio) == WRITE) ? "write" : "read",
 321                          (unsigned long long) bio->bi_iter.bi_sector,
 322                          (unsigned long long) bio_end_sector(bio) - 1);
 323
 324                 call_bio_endio(r1_bio);
 325         }
 326         /*
 327          * Wake up any possible resync thread that waits for the device
 328          * to go idle.  All I/Os, even write-behind writes, are done.
 329          */
 330         allow_barrier(conf, r1_bio->sector);
 331
 332         free_r1bio(r1_bio);
 333 }
 334
 335 /*
 336  * Update disk head position estimator based on IRQ completion info.
 337  */
 338 static inline void update_head_pos(int disk, struct r1bio *r1_bio)
 339 {
 340         struct r1conf *conf = r1_bio->mddev->private;
 341
 342         conf->mirrors[disk].head_position =
 343                 r1_bio->sector + (r1_bio->sectors);
 344 }
 345
 346 /*
 347  * Find the disk number which triggered given bio
 348  */
 349 static int find_bio_disk(struct r1bio *r1_bio, struct bio *bio)
 350 {
 351         int mirror;
 352         struct r1conf *conf = r1_bio->mddev->private;
 353         int raid_disks = conf->raid_disks;
 354
 355         for (mirror = 0; mirror < raid_disks * 2; mirror++)
 356                 if (r1_bio->bios[mirror] == bio)
 357                         break;
 358
 359         BUG_ON(mirror == raid_disks * 2);
 360         update_head_pos(mirror, r1_bio);
 361
 362         return mirror;
 363 }
 364
 365 static void raid1_end_read_request(struct bio *bio)
 366 {
 367         int uptodate = !bio->bi_status;
 368         struct r1bio *r1_bio = bio->bi_private;
 369         struct r1conf *conf = r1_bio->mddev->private;
 370         struct md_rdev *rdev = conf->mirrors[r1_bio->read_disk].rdev;
 371
 372         /*
 373          * this branch is our 'one mirror IO has finished' event handler:
 374          */
 375         update_head_pos(r1_bio->read_disk, r1_bio);
 376
 377         if (uptodate)
 378                 set_bit(R1BIO_Uptodate, &r1_bio->state);
 379         else if (test_bit(FailFast, &rdev->flags) &&
 380                  test_bit(R1BIO_FailFast, &r1_bio->state))
 381                 /* This was a fail-fast read so we definitely
 382                  * want to retry */
 383                 ;
 384         else {
 385                 /* If all other devices have failed, we want to return
 386                  * the error upwards rather than fail the last device.
 387                  * Here we redefine "uptodate" to mean "Don't want to retry"
 388                  */
 389                 unsigned long flags;
 390                 spin_lock_irqsave(&conf->device_lock, flags);
 391                 if (r1_bio->mddev->degraded == conf->raid_disks ||
 392                     (r1_bio->mddev->degraded == conf->raid_disks-1 &&
 393                      test_bit(In_sync, &rdev->flags)))
 394                         uptodate = 1;
 395                 spin_unlock_irqrestore(&conf->device_lock, flags);
 396         }
 397
 398         if (uptodate) {
 399                 raid_end_bio_io(r1_bio);
 400                 rdev_dec_pending(rdev, conf->mddev);
 401         } else {
 402                 /*
 403                  * oops, read error:
 404                  */
 405                 char b[BDEVNAME_SIZE];
 406                 pr_err_ratelimited("md/raid1:%s: %s: rescheduling sector %llu\n",
 407                                    mdname(conf->mddev),
 408                                    bdevname(rdev->bdev, b),
 409                                    (unsigned long long)r1_bio->sector);
 410                 set_bit(R1BIO_ReadError, &r1_bio->state);
 411                 reschedule_retry(r1_bio);
 412                 /* don't drop the reference on read_disk yet */
 413         }
 414 }
 415
 416 static void close_write(struct r1bio *r1_bio)
 417 {
 418         /* it really is the end of this request */
 419         if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
 420                 bio_free_pages(r1_bio->behind_master_bio);
 421                 bio_put(r1_bio->behind_master_bio);
 422                 r1_bio->behind_master_bio = NULL;
 423         }
 424         /* clear the bitmap if all writes complete successfully */
 425         md_bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
 426                            r1_bio->sectors,
 427                            !test_bit(R1BIO_Degraded, &r1_bio->state),
 428                            test_bit(R1BIO_BehindIO, &r1_bio->state));
 429         md_write_end(r1_bio->mddev);
 430 }
 431
 432 static void r1_bio_write_done(struct r1bio *r1_bio)
 433 {
 434         if (!atomic_dec_and_test(&r1_bio->remaining))
 435                 return;
 436
 437         if (test_bit(R1BIO_WriteError, &r1_bio->state))
 438                 reschedule_retry(r1_bio);
 439         else {
 440                 close_write(r1_bio);
 441                 if (test_bit(R1BIO_MadeGood, &r1_bio->state))
 442                         reschedule_retry(r1_bio);
 443                 else
 444                         raid_end_bio_io(r1_bio);
 445         }
 446 }
 447
 448 static void raid1_end_write_request(struct bio *bio)
 449 {
 450         struct r1bio *r1_bio = bio->bi_private;
 451         int behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
 452         struct r1conf *conf = r1_bio->mddev->private;
 453         struct bio *to_put = NULL;
 454         int mirror = find_bio_disk(r1_bio, bio);
 455         struct md_rdev *rdev = conf->mirrors[mirror].rdev;
 456         bool discard_error;
 457         sector_t lo = r1_bio->sector;
 458         sector_t hi = r1_bio->sector + r1_bio->sectors;
 459
 460         discard_error = bio->bi_status && bio_op(bio) == REQ_OP_DISCARD;
 461
 462         /*
 463          * 'one mirror IO has finished' event handler:
 464          */
 465         if (bio->bi_status && !discard_error) {
 466                 set_bit(WriteErrorSeen, &rdev->flags);
 467                 if (!test_and_set_bit(WantReplacement, &rdev->flags))
 468                         set_bit(MD_RECOVERY_NEEDED, &
 469                                 conf->mddev->recovery);
 470
 471                 if (test_bit(FailFast, &rdev->flags) &&
 472                     (bio->bi_opf & MD_FAILFAST) &&
 473                     /* We never try FailFast to WriteMostly devices */
 474                     !test_bit(WriteMostly, &rdev->flags)) {
 475                         md_error(r1_bio->mddev, rdev);
 476                 }
 477
 478                 /*
 479                  * When the device is faulty, it is not necessary to
 480                  * handle write error.
 481                  */
 482                 if (!test_bit(Faulty, &rdev->flags))
 483                         set_bit(R1BIO_WriteError, &r1_bio->state);
 484                 else {
 485                         /* Fail the request */
 486                         set_bit(R1BIO_Degraded, &r1_bio->state);
 487                         /* Finished with this branch */
 488                         r1_bio->bios[mirror] = NULL;
 489                         to_put = bio;
 490                 }
 491         } else {
 492                 /*
 493                  * Set R1BIO_Uptodate in our master bio, so that we
 494                  * will return a good error code for to the higher
 495                  * levels even if IO on some other mirrored buffer
 496                  * fails.
 497                  *
 498                  * The 'master' represents the composite IO operation
 499                  * to user-side. So if something waits for IO, then it
 500                  * will wait for the 'master' bio.
 501                  */
 502                 sector_t first_bad;
 503                 int bad_sectors;
 504
 505                 r1_bio->bios[mirror] = NULL;
 506                 to_put = bio;
 507                 /*
 508                  * Do not set R1BIO_Uptodate if the current device is
 509                  * rebuilding or Faulty. This is because we cannot use
 510                  * such device for properly reading the data back (we could
 511                  * potentially use it, if the current write would have felt
 512                  * before rdev->recovery_offset, but for simplicity we don't
 513                  * check this here.
 514                  */
 515                 if (test_bit(In_sync, &rdev->flags) &&
 516                     !test_bit(Faulty, &rdev->flags))
 517                         set_bit(R1BIO_Uptodate, &r1_bio->state);
 518
 519                 /* Maybe we can clear some bad blocks. */
 520                 if (is_badblock(rdev, r1_bio->sector, r1_bio->sectors,
 521                                 &first_bad, &bad_sectors) && !discard_error) {
 522                         r1_bio->bios[mirror] = IO_MADE_GOOD;
 523                         set_bit(R1BIO_MadeGood, &r1_bio->state);
 524                 }
 525         }
 526
 527         if (behind) {
 528                 if (test_bit(CollisionCheck, &rdev->flags))
 529                         remove_serial(rdev, lo, hi);
 530                 if (test_bit(WriteMostly, &rdev->flags))
 531                         atomic_dec(&r1_bio->behind_remaining);
 532
 533                 /*
 534                  * In behind mode, we ACK the master bio once the I/O
 535                  * has safely reached all non-writemostly
 536                  * disks. Setting the Returned bit ensures that this
 537                  * gets done only once -- we don't ever want to return
 538                  * -EIO here, instead we'll wait
 539                  */
 540                 if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
 541                     test_bit(R1BIO_Uptodate, &r1_bio->state)) {
 542                         /* Maybe we can return now */
 543                         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 544                                 struct bio *mbio = r1_bio->master_bio;
 545                                 pr_debug("raid1: behind end write sectors"
 546                                          " %llu-%llu\n",
 547                                          (unsigned long long) mbio->bi_iter.bi_sector,
 548                                          (unsigned long long) bio_end_sector(mbio) - 1);
 549                                 call_bio_endio(r1_bio);
 550                         }
 551                 }
 552         } else if (rdev->mddev->serialize_policy)
 553                 remove_serial(rdev, lo, hi);
 554         if (r1_bio->bios[mirror] == NULL)
 555                 rdev_dec_pending(rdev, conf->mddev);
 556
 557         /*
 558          * Let's see if all mirrored write operations have finished
 559          * already.
 560          */
 561         r1_bio_write_done(r1_bio);
 562
 563         if (to_put)
 564                 bio_put(to_put);
 565 }
 566
 567 static sector_t align_to_barrier_unit_end(sector_t start_sector,
 568                                           sector_t sectors)
 569 {
 570         sector_t len;
 571
 572         WARN_ON(sectors == 0);
 573         /*
 574          * len is the number of sectors from start_sector to end of the
 575          * barrier unit which start_sector belongs to.
 576          */
 577         len = round_up(start_sector + 1, BARRIER_UNIT_SECTOR_SIZE) -
 578               start_sector;
 579
 580         if (len > sectors)
 581                 len = sectors;
 582
 583         return len;
 584 }
 585
 586 /*
 587  * This routine returns the disk from which the requested read should
 588  * be done. There is a per-array 'next expected sequential IO' sector
 589  * number - if this matches on the next IO then we use the last disk.
 590  * There is also a per-disk 'last know head position' sector that is
 591  * maintained from IRQ contexts, both the normal and the resync IO
 592  * completion handlers update this position correctly. If there is no
 593  * perfect sequential match then we pick the disk whose head is closest.
 594  *
 595  * If there are 2 mirrors in the same 2 devices, performance degrades
 596  * because position is mirror, not device based.
 597  *
 598  * The rdev for the device selected will have nr_pending incremented.
 599  */
 600 static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sectors)
 601 {
 602         const sector_t this_sector = r1_bio->sector;
 603         int sectors;
 604         int best_good_sectors;
 605         int best_disk, best_dist_disk, best_pending_disk;
 606         int has_nonrot_disk;
 607         int disk;
 608         sector_t best_dist;
 609         unsigned int min_pending;
 610         struct md_rdev *rdev;
 611         int choose_first;
 612         int choose_next_idle;
 613
 614         rcu_read_lock();
 615         /*
 616          * Check if we can balance. We can balance on the whole
 617          * device if no resync is going on, or below the resync window.
 618          * We take the first readable disk when above the resync window.
 619          */
 620  retry:
 621         sectors = r1_bio->sectors;
 622         best_disk = -1;
 623         best_dist_disk = -1;
 624         best_dist = MaxSector;
 625         best_pending_disk = -1;
 626         min_pending = UINT_MAX;
 627         best_good_sectors = 0;
 628         has_nonrot_disk = 0;
 629         choose_next_idle = 0;
 630         clear_bit(R1BIO_FailFast, &r1_bio->state);
 631
 632         if ((conf->mddev->recovery_cp < this_sector + sectors) ||
 633             (mddev_is_clustered(conf->mddev) &&
 634             md_cluster_ops->area_resyncing(conf->mddev, READ, this_sector,
 635                     this_sector + sectors)))
 636                 choose_first = 1;
 637         else
 638                 choose_first = 0;
 639
 640         for (disk = 0 ; disk < conf->raid_disks * 2 ; disk++) {
 641                 sector_t dist;
 642                 sector_t first_bad;
 643                 int bad_sectors;
 644                 unsigned int pending;
 645                 bool nonrot;
 646
 647                 rdev = rcu_dereference(conf->mirrors[disk].rdev);
 648                 if (r1_bio->bios[disk] == IO_BLOCKED
 649                     || rdev == NULL
 650                     || test_bit(Faulty, &rdev->flags))
 651                         continue;
 652                 if (!test_bit(In_sync, &rdev->flags) &&
 653                     rdev->recovery_offset < this_sector + sectors)
 654                         continue;
 655                 if (test_bit(WriteMostly, &rdev->flags)) {
 656                         /* Don't balance among write-mostly, just
 657                          * use the first as a last resort */
 658                         if (best_dist_disk < 0) {
 659                                 if (is_badblock(rdev, this_sector, sectors,
 660                                                 &first_bad, &bad_sectors)) {
 661                                         if (first_bad <= this_sector)
 662                                                 /* Cannot use this */
 663                                                 continue;
 664                                         best_good_sectors = first_bad - this_sector;
 665                                 } else
 666                                         best_good_sectors = sectors;
 667                                 best_dist_disk = disk;
 668                                 best_pending_disk = disk;
 669                         }
 670                         continue;
 671                 }
 672                 /* This is a reasonable device to use.  It might
 673                  * even be best.
 674                  */
 675                 if (is_badblock(rdev, this_sector, sectors,
 676                                 &first_bad, &bad_sectors)) {
 677                         if (best_dist < MaxSector)
 678                                 /* already have a better device */
 679                                 continue;
 680                         if (first_bad <= this_sector) {
 681                                 /* cannot read here. If this is the 'primary'
 682                                  * device, then we must not read beyond
 683                                  * bad_sectors from another device..
 684                                  */
 685                                 bad_sectors -= (this_sector - first_bad);
 686                                 if (choose_first && sectors > bad_sectors)
 687                                         sectors = bad_sectors;
 688                                 if (best_good_sectors > sectors)
 689                                         best_good_sectors = sectors;
 690
 691                         } else {
 692                                 sector_t good_sectors = first_bad - this_sector;
 693                                 if (good_sectors > best_good_sectors) {
 694                                         best_good_sectors = good_sectors;
 695                                         best_disk = disk;
 696                                 }
 697                                 if (choose_first)
 698                                         break;
 699                         }
 700                         continue;
 701                 } else {
 702                         if ((sectors > best_good_sectors) && (best_disk >= 0))
 703                                 best_disk = -1;
 704                         best_good_sectors = sectors;
 705                 }
 706
 707                 if (best_disk >= 0)
 708                         /* At least two disks to choose from so failfast is OK */
 709                         set_bit(R1BIO_FailFast, &r1_bio->state);
 710
 711                 nonrot = bdev_nonrot(rdev->bdev);
 712                 has_nonrot_disk |= nonrot;
 713                 pending = atomic_read(&rdev->nr_pending);
 714                 dist = abs(this_sector - conf->mirrors[disk].head_position);
 715                 if (choose_first) {
 716                         best_disk = disk;
 717                         break;
 718                 }
 719                 /* Don't change to another disk for sequential reads */
 720                 if (conf->mirrors[disk].next_seq_sect == this_sector
 721                     || dist == 0) {
 722                         int opt_iosize = bdev_io_opt(rdev->bdev) >> 9;
 723                         struct raid1_info *mirror = &conf->mirrors[disk];
 724
 725                         best_disk = disk;
 726                         /*
 727                          * If buffered sequential IO size exceeds optimal
 728                          * iosize, check if there is idle disk. If yes, choose
 729                          * the idle disk. read_balance could already choose an
 730                          * idle disk before noticing it's a sequential IO in
 731                          * this disk. This doesn't matter because this disk
 732                          * will idle, next time it will be utilized after the
 733                          * first disk has IO size exceeds optimal iosize. In
 734                          * this way, iosize of the first disk will be optimal
 735                          * iosize at least. iosize of the second disk might be
 736                          * small, but not a big deal since when the second disk
 737                          * starts IO, the first disk is likely still busy.
 738                          */
 739                         if (nonrot && opt_iosize > 0 &&
 740                             mirror->seq_start != MaxSector &&
 741                             mirror->next_seq_sect > opt_iosize &&
 742                             mirror->next_seq_sect - opt_iosize >=
 743                             mirror->seq_start) {
 744                                 choose_next_idle = 1;
 745                                 continue;
 746                         }
 747                         break;
 748                 }
 749
 750                 if (choose_next_idle)
 751                         continue;
 752
 753                 if (min_pending > pending) {
 754                         min_pending = pending;
 755                         best_pending_disk = disk;
 756                 }
 757
 758                 if (dist < best_dist) {
 759                         best_dist = dist;
 760                         best_dist_disk = disk;
 761                 }
 762         }
 763
 764         /*
 765          * If all disks are rotational, choose the closest disk. If any disk is
 766          * non-rotational, choose the disk with less pending request even the
 767          * disk is rotational, which might/might not be optimal for raids with
 768          * mixed ratation/non-rotational disks depending on workload.
 769          */
 770         if (best_disk == -1) {
 771                 if (has_nonrot_disk || min_pending == 0)
 772                         best_disk = best_pending_disk;
 773                 else
 774                         best_disk = best_dist_disk;
 775         }
 776
 777         if (best_disk >= 0) {
 778                 rdev = rcu_dereference(conf->mirrors[best_disk].rdev);
 779                 if (!rdev)
 780                         goto retry;
 781                 atomic_inc(&rdev->nr_pending);
 782                 sectors = best_good_sectors;
 783
 784                 if (conf->mirrors[best_disk].next_seq_sect != this_sector)
 785                         conf->mirrors[best_disk].seq_start = this_sector;
 786
 787                 conf->mirrors[best_disk].next_seq_sect = this_sector + sectors;
 788         }
 789         rcu_read_unlock();
 790         *max_sectors = sectors;
 791
 792         return best_disk;
 793 }
 794
 795 static void flush_bio_list(struct r1conf *conf, struct bio *bio)
 796 {
 797         /* flush any pending bitmap writes to disk before proceeding w/ I/O */
 798         md_bitmap_unplug(conf->mddev->bitmap);
 799         wake_up(&conf->wait_barrier);
 800
 801         while (bio) { /* submit pending writes */
 802                 struct bio *next = bio->bi_next;
 803                 struct md_rdev *rdev = (void *)bio->bi_bdev;
 804                 bio->bi_next = NULL;
 805                 bio_set_dev(bio, rdev->bdev);
 806                 if (test_bit(Faulty, &rdev->flags)) {
 807                         bio_io_error(bio);
 808                 } else if (unlikely((bio_op(bio) == REQ_OP_DISCARD) &&
 809                                     !blk_queue_discard(bio->bi_bdev->bd_disk->queue)))
 810                         /* Just ignore it */
 811                         bio_endio(bio);
 812                 else
 813                         submit_bio_noacct(bio);
 814                 bio = next;
 815                 cond_resched();
 816         }
 817 }
 818
 819 static void flush_pending_writes(struct r1conf *conf)
 820 {
 821         /* Any writes that have been queued but are awaiting
 822          * bitmap updates get flushed here.
 823          */
 824         spin_lock_irq(&conf->device_lock);
 825
 826         if (conf->pending_bio_list.head) {
 827                 struct blk_plug plug;
 828                 struct bio *bio;
 829
 830                 bio = bio_list_get(&conf->pending_bio_list);
 831                 spin_unlock_irq(&conf->device_lock);
 832
 833                 /*
 834                  * As this is called in a wait_event() loop (see freeze_array),
 835                  * current->state might be TASK_UNINTERRUPTIBLE which will
 836                  * cause a warning when we prepare to wait again.  As it is
 837                  * rare that this path is taken, it is perfectly safe to force
 838                  * us to go around the wait_event() loop again, so the warning
 839                  * is a false-positive.  Silence the warning by resetting
 840                  * thread state
 841                  */
 842                 __set_current_state(TASK_RUNNING);
 843                 blk_start_plug(&plug);
 844                 flush_bio_list(conf, bio);
 845                 blk_finish_plug(&plug);
 846         } else
 847                 spin_unlock_irq(&conf->device_lock);
 848 }
 849
 850 /* Barriers....
 851  * Sometimes we need to suspend IO while we do something else,
 852  * either some resync/recovery, or reconfigure the array.
 853  * To do this we raise a 'barrier'.
 854  * The 'barrier' is a counter that can be raised multiple times
 855  * to count how many activities are happening which preclude
 856  * normal IO.
 857  * We can only raise the barrier if there is no pending IO.
 858  * i.e. if nr_pending == 0.
 859  * We choose only to raise the barrier if no-one is waiting for the
 860  * barrier to go down.  This means that as soon as an IO request
 861  * is ready, no other operations which require a barrier will start
 862  * until the IO request has had a chance.
 863  *
 864  * So: regular IO calls 'wait_barrier'.  When that returns there
 865  *    is no backgroup IO happening,  It must arrange to call
 866  *    allow_barrier when it has finished its IO.
 867  * backgroup IO calls must call raise_barrier.  Once that returns
 868  *    there is no normal IO happeing.  It must arrange to call
 869  *    lower_barrier when the particular background IO completes.
 870  *
 871  * If resync/recovery is interrupted, returns -EINTR;
 872  * Otherwise, returns 0.
 873  */
 874 static int raise_barrier(struct r1conf *conf, sector_t sector_nr)
 875 {
 876         int idx = sector_to_idx(sector_nr);
 877
 878         spin_lock_irq(&conf->resync_lock);
 879
 880         /* Wait until no block IO is waiting */
 881         wait_event_lock_irq(conf->wait_barrier,
 882                             !atomic_read(&conf->nr_waiting[idx]),
 883                             conf->resync_lock);
 884
 885         /* block any new IO from starting */
 886         atomic_inc(&conf->barrier[idx]);
 887         /*
 888          * In raise_barrier() we firstly increase conf->barrier[idx] then
 889          * check conf->nr_pending[idx]. In _wait_barrier() we firstly
 890          * increase conf->nr_pending[idx] then check conf->barrier[idx].
 891          * A memory barrier here to make sure conf->nr_pending[idx] won't
 892          * be fetched before conf->barrier[idx] is increased. Otherwise
 893          * there will be a race between raise_barrier() and _wait_barrier().
 894          */
 895         smp_mb__after_atomic();
 896
 897         /* For these conditions we must wait:
 898          * A: while the array is in frozen state
 899          * B: while conf->nr_pending[idx] is not 0, meaning regular I/O
 900          *    existing in corresponding I/O barrier bucket.
 901          * C: while conf->barrier[idx] >= RESYNC_DEPTH, meaning reaches
 902          *    max resync count which allowed on current I/O barrier bucket.
 903          */
 904         wait_event_lock_irq(conf->wait_barrier,
 905                             (!conf->array_frozen &&
 906                              !atomic_read(&conf->nr_pending[idx]) &&
 907                              atomic_read(&conf->barrier[idx]) < RESYNC_DEPTH) ||
 908                                 test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery),
 909                             conf->resync_lock);
 910
 911         if (test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
 912                 atomic_dec(&conf->barrier[idx]);
 913                 spin_unlock_irq(&conf->resync_lock);
 914                 wake_up(&conf->wait_barrier);
 915                 return -EINTR;
 916         }
 917
 918         atomic_inc(&conf->nr_sync_pending);
 919         spin_unlock_irq(&conf->resync_lock);
 920
 921         return 0;
 922 }
 923
 924 static void lower_barrier(struct r1conf *conf, sector_t sector_nr)
 925 {
 926         int idx = sector_to_idx(sector_nr);
 927
 928         BUG_ON(atomic_read(&conf->barrier[idx]) <= 0);
 929
 930         atomic_dec(&conf->barrier[idx]);
 931         atomic_dec(&conf->nr_sync_pending);
 932         wake_up(&conf->wait_barrier);
 933 }
 934
 935 static bool _wait_barrier(struct r1conf *conf, int idx, bool nowait)
 936 {
 937         bool ret = true;
 938
 939         /*
 940          * We need to increase conf->nr_pending[idx] very early here,
 941          * then raise_barrier() can be blocked when it waits for
 942          * conf->nr_pending[idx] to be 0. Then we can avoid holding
 943          * conf->resync_lock when there is no barrier raised in same
 944          * barrier unit bucket. Also if the array is frozen, I/O
 945          * should be blocked until array is unfrozen.
 946          */
 947         atomic_inc(&conf->nr_pending[idx]);
 948         /*
 949          * In _wait_barrier() we firstly increase conf->nr_pending[idx], then
 950          * check conf->barrier[idx]. In raise_barrier() we firstly increase
 951          * conf->barrier[idx], then check conf->nr_pending[idx]. A memory
 952          * barrier is necessary here to make sure conf->barrier[idx] won't be
 953          * fetched before conf->nr_pending[idx] is increased. Otherwise there
 954          * will be a race between _wait_barrier() and raise_barrier().
 955          */
 956         smp_mb__after_atomic();
 957
 958         /*
 959          * Don't worry about checking two atomic_t variables at same time
 960          * here. If during we check conf->barrier[idx], the array is
 961          * frozen (conf->array_frozen is 1), and chonf->barrier[idx] is
 962          * 0, it is safe to return and make the I/O continue. Because the
 963          * array is frozen, all I/O returned here will eventually complete
 964          * or be queued, no race will happen. See code comment in
 965          * frozen_array().
 966          */
 967         if (!READ_ONCE(conf->array_frozen) &&
 968             !atomic_read(&conf->barrier[idx]))
 969                 return ret;
 970
 971         /*
 972          * After holding conf->resync_lock, conf->nr_pending[idx]
 973          * should be decreased before waiting for barrier to drop.
 974          * Otherwise, we may encounter a race condition because
 975          * raise_barrer() might be waiting for conf->nr_pending[idx]
 976          * to be 0 at same time.
 977          */
 978         spin_lock_irq(&conf->resync_lock);
 979         atomic_inc(&conf->nr_waiting[idx]);
 980         atomic_dec(&conf->nr_pending[idx]);
 981         /*
 982          * In case freeze_array() is waiting for
 983          * get_unqueued_pending() == extra
 984          */
 985         wake_up(&conf->wait_barrier);
 986         /* Wait for the barrier in same barrier unit bucket to drop. */
 987
 988         /* Return false when nowait flag is set */
 989         if (nowait) {
 990                 ret = false;
 991         } else {
 992                 wait_event_lock_irq(conf->wait_barrier,
 993                                 !conf->array_frozen &&
 994                                 !atomic_read(&conf->barrier[idx]),
 995                                 conf->resync_lock);
 996                 atomic_inc(&conf->nr_pending[idx]);
 997         }
 998
 999         atomic_dec(&conf->nr_waiting[idx]);
1000         spin_unlock_irq(&conf->resync_lock);
1001         return ret;
1002 }
1003
1004 static bool wait_read_barrier(struct r1conf *conf, sector_t sector_nr, bool nowait)
1005 {
1006         int idx = sector_to_idx(sector_nr);
1007         bool ret = true;
1008
1009         /*
1010          * Very similar to _wait_barrier(). The difference is, for read
1011          * I/O we don't need wait for sync I/O, but if the whole array
1012          * is frozen, the read I/O still has to wait until the array is
1013          * unfrozen. Since there is no ordering requirement with
1014          * conf->barrier[idx] here, memory barrier is unnecessary as well.
1015          */
1016         atomic_inc(&conf->nr_pending[idx]);
1017
1018         if (!READ_ONCE(conf->array_frozen))
1019                 return ret;
1020
1021         spin_lock_irq(&conf->resync_lock);
1022         atomic_inc(&conf->nr_waiting[idx]);
1023         atomic_dec(&conf->nr_pending[idx]);
1024         /*
1025          * In case freeze_array() is waiting for
1026          * get_unqueued_pending() == extra
1027          */
1028         wake_up(&conf->wait_barrier);
1029         /* Wait for array to be unfrozen */
1030
1031         /* Return false when nowait flag is set */
1032         if (nowait) {
1033                 /* Return false when nowait flag is set */
1034                 ret = false;
1035         } else {
1036                 wait_event_lock_irq(conf->wait_barrier,
1037                                 !conf->array_frozen,
1038                                 conf->resync_lock);
1039                 atomic_inc(&conf->nr_pending[idx]);
1040         }
1041
1042         atomic_dec(&conf->nr_waiting[idx]);
1043         spin_unlock_irq(&conf->resync_lock);
1044         return ret;
1045 }
1046
1047 static bool wait_barrier(struct r1conf *conf, sector_t sector_nr, bool nowait)
1048 {
1049         int idx = sector_to_idx(sector_nr);
1050
1051         return _wait_barrier(conf, idx, nowait);
1052 }
1053
1054 static void _allow_barrier(struct r1conf *conf, int idx)
1055 {
1056         atomic_dec(&conf->nr_pending[idx]);
1057         wake_up(&conf->wait_barrier);
1058 }
1059
1060 static void allow_barrier(struct r1conf *conf, sector_t sector_nr)
1061 {
1062         int idx = sector_to_idx(sector_nr);
1063
1064         _allow_barrier(conf, idx);
1065 }
1066
1067 /* conf->resync_lock should be held */
1068 static int get_unqueued_pending(struct r1conf *conf)
1069 {
1070         int idx, ret;
1071
1072         ret = atomic_read(&conf->nr_sync_pending);
1073         for (idx = 0; idx < BARRIER_BUCKETS_NR; idx++)
1074                 ret += atomic_read(&conf->nr_pending[idx]) -
1075                         atomic_read(&conf->nr_queued[idx]);
1076
1077         return ret;
1078 }
1079
1080 static void freeze_array(struct r1conf *conf, int extra)
1081 {
1082         /* Stop sync I/O and normal I/O and wait for everything to
1083          * go quiet.
1084          * This is called in two situations:
1085          * 1) management command handlers (reshape, remove disk, quiesce).
1086          * 2) one normal I/O request failed.
1087
1088          * After array_frozen is set to 1, new sync IO will be blocked at
1089          * raise_barrier(), and new normal I/O will blocked at _wait_barrier()
1090          * or wait_read_barrier(). The flying I/Os will either complete or be
1091          * queued. When everything goes quite, there are only queued I/Os left.
1092
1093          * Every flying I/O contributes to a conf->nr_pending[idx], idx is the
1094          * barrier bucket index which this I/O request hits. When all sync and
1095          * normal I/O are queued, sum of all conf->nr_pending[] will match sum
1096          * of all conf->nr_queued[]. But normal I/O failure is an exception,
1097          * in handle_read_error(), we may call freeze_array() before trying to
1098          * fix the read error. In this case, the error read I/O is not queued,
1099          * so get_unqueued_pending() == 1.
1100          *
1101          * Therefore before this function returns, we need to wait until
1102          * get_unqueued_pendings(conf) gets equal to extra. For
1103          * normal I/O context, extra is 1, in rested situations extra is 0.
1104          */
1105         spin_lock_irq(&conf->resync_lock);
1106         conf->array_frozen = 1;
1107         raid1_log(conf->mddev, "wait freeze");
1108         wait_event_lock_irq_cmd(
1109                 conf->wait_barrier,
1110                 get_unqueued_pending(conf) == extra,
1111                 conf->resync_lock,
1112                 flush_pending_writes(conf));
1113         spin_unlock_irq(&conf->resync_lock);
1114 }
1115 static void unfreeze_array(struct r1conf *conf)
1116 {
1117         /* reverse the effect of the freeze */
1118         spin_lock_irq(&conf->resync_lock);
1119         conf->array_frozen = 0;
1120         spin_unlock_irq(&conf->resync_lock);
1121         wake_up(&conf->wait_barrier);
1122 }
1123
1124 static void alloc_behind_master_bio(struct r1bio *r1_bio,
1125                                            struct bio *bio)
1126 {
1127         int size = bio->bi_iter.bi_size;
1128         unsigned vcnt = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
1129         int i = 0;
1130         struct bio *behind_bio = NULL;
1131
1132         behind_bio = bio_alloc_bioset(NULL, vcnt, 0, GFP_NOIO,
1133                                       &r1_bio->mddev->bio_set);
1134         if (!behind_bio)
1135                 return;
1136
1137         /* discard op, we don't support writezero/writesame yet */
1138         if (!bio_has_data(bio)) {
1139                 behind_bio->bi_iter.bi_size = size;
1140                 goto skip_copy;
1141         }
1142
1143         while (i < vcnt && size) {
1144                 struct page *page;
1145                 int len = min_t(int, PAGE_SIZE, size);
1146
1147                 page = alloc_page(GFP_NOIO);
1148                 if (unlikely(!page))
1149                         goto free_pages;
1150
1151                 bio_add_page(behind_bio, page, len, 0);
1152
1153                 size -= len;
1154                 i++;
1155         }
1156
1157         bio_copy_data(behind_bio, bio);
1158 skip_copy:
1159         r1_bio->behind_master_bio = behind_bio;
1160         set_bit(R1BIO_BehindIO, &r1_bio->state);
1161
1162         return;
1163
1164 free_pages:
1165         pr_debug("%dB behind alloc failed, doing sync I/O\n",
1166                  bio->bi_iter.bi_size);
1167         bio_free_pages(behind_bio);
1168         bio_put(behind_bio);
1169 }
1170
1171 static void raid1_unplug(struct blk_plug_cb *cb, bool from_schedule)
1172 {
1173         struct raid1_plug_cb *plug = container_of(cb, struct raid1_plug_cb,
1174                                                   cb);
1175         struct mddev *mddev = plug->cb.data;
1176         struct r1conf *conf = mddev->private;
1177         struct bio *bio;
1178
1179         if (from_schedule || current->bio_list) {
1180                 spin_lock_irq(&conf->device_lock);
1181                 bio_list_merge(&conf->pending_bio_list, &plug->pending);
1182                 spin_unlock_irq(&conf->device_lock);
1183                 wake_up(&conf->wait_barrier);
1184                 md_wakeup_thread(mddev->thread);
1185                 kfree(plug);
1186                 return;
1187         }
1188
1189         /* we aren't scheduling, so we can do the write-out directly. */
1190         bio = bio_list_get(&plug->pending);
1191         flush_bio_list(conf, bio);
1192         kfree(plug);
1193 }
1194
1195 static void init_r1bio(struct r1bio *r1_bio, struct mddev *mddev, struct bio *bio)
1196 {
1197         r1_bio->master_bio = bio;
1198         r1_bio->sectors = bio_sectors(bio);
1199         r1_bio->state = 0;
1200         r1_bio->mddev = mddev;
1201         r1_bio->sector = bio->bi_iter.bi_sector;
1202 }
1203
1204 static inline struct r1bio *
1205 alloc_r1bio(struct mddev *mddev, struct bio *bio)
1206 {
1207         struct r1conf *conf = mddev->private;
1208         struct r1bio *r1_bio;
1209
1210         r1_bio = mempool_alloc(&conf->r1bio_pool, GFP_NOIO);
1211         /* Ensure no bio records IO_BLOCKED */
1212         memset(r1_bio->bios, 0, conf->raid_disks * sizeof(r1_bio->bios[0]));
1213         init_r1bio(r1_bio, mddev, bio);
1214         return r1_bio;
1215 }
1216
1217 static void raid1_read_request(struct mddev *mddev, struct bio *bio,
1218                                int max_read_sectors, struct r1bio *r1_bio)
1219 {
1220         struct r1conf *conf = mddev->private;
1221         struct raid1_info *mirror;
1222         struct bio *read_bio;
1223         struct bitmap *bitmap = mddev->bitmap;
1224         const int op = bio_op(bio);
1225         const unsigned long do_sync = (bio->bi_opf & REQ_SYNC);
1226         int max_sectors;
1227         int rdisk;
1228         bool r1bio_existed = !!r1_bio;
1229         char b[BDEVNAME_SIZE];
1230
1231         /*
1232          * If r1_bio is set, we are blocking the raid1d thread
1233          * so there is a tiny risk of deadlock.  So ask for
1234          * emergency memory if needed.
1235          */
1236         gfp_t gfp = r1_bio ? (GFP_NOIO | __GFP_HIGH) : GFP_NOIO;
1237
1238         if (r1bio_existed) {
1239                 /* Need to get the block device name carefully */
1240                 struct md_rdev *rdev;
1241                 rcu_read_lock();
1242                 rdev = rcu_dereference(conf->mirrors[r1_bio->read_disk].rdev);
1243                 if (rdev)
1244                         bdevname(rdev->bdev, b);
1245                 else
1246                         strcpy(b, "???");
1247                 rcu_read_unlock();
1248         }
1249
1250         /*
1251          * Still need barrier for READ in case that whole
1252          * array is frozen.
1253          */
1254         if (!wait_read_barrier(conf, bio->bi_iter.bi_sector,
1255                                 bio->bi_opf & REQ_NOWAIT)) {
1256                 bio_wouldblock_error(bio);
1257                 return;
1258         }
1259
1260         if (!r1_bio)
1261                 r1_bio = alloc_r1bio(mddev, bio);
1262         else
1263                 init_r1bio(r1_bio, mddev, bio);
1264         r1_bio->sectors = max_read_sectors;
1265
1266         /*
1267          * make_request() can abort the operation when read-ahead is being
1268          * used and no empty request is available.
1269          */
1270         rdisk = read_balance(conf, r1_bio, &max_sectors);
1271
1272         if (rdisk < 0) {
1273                 /* couldn't find anywhere to read from */
1274                 if (r1bio_existed) {
1275                         pr_crit_ratelimited("md/raid1:%s: %s: unrecoverable I/O read error for block %llu\n",
1276                                             mdname(mddev),
1277                                             b,
1278                                             (unsigned long long)r1_bio->sector);
1279                 }
1280                 raid_end_bio_io(r1_bio);
1281                 return;
1282         }
1283         mirror = conf->mirrors + rdisk;
1284
1285         if (r1bio_existed)
1286                 pr_info_ratelimited("md/raid1:%s: redirecting sector %llu to other mirror: %s\n",
1287                                     mdname(mddev),
1288                                     (unsigned long long)r1_bio->sector,
1289                                     bdevname(mirror->rdev->bdev, b));
1290
1291         if (test_bit(WriteMostly, &mirror->rdev->flags) &&
1292             bitmap) {
1293                 /*
1294                  * Reading from a write-mostly device must take care not to
1295                  * over-take any writes that are 'behind'
1296                  */
1297                 raid1_log(mddev, "wait behind writes");
1298                 wait_event(bitmap->behind_wait,
1299                            atomic_read(&bitmap->behind_writes) == 0);
1300         }
1301
1302         if (max_sectors < bio_sectors(bio)) {
1303                 struct bio *split = bio_split(bio, max_sectors,
1304                                               gfp, &conf->bio_split);
1305                 bio_chain(split, bio);
1306                 submit_bio_noacct(bio);
1307                 bio = split;
1308                 r1_bio->master_bio = bio;
1309                 r1_bio->sectors = max_sectors;
1310         }
1311
1312         r1_bio->read_disk = rdisk;
1313
1314         if (!r1bio_existed && blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
1315                 r1_bio->start_time = bio_start_io_acct(bio);
1316
1317         read_bio = bio_alloc_clone(mirror->rdev->bdev, bio, gfp,
1318                                    &mddev->bio_set);
1319
1320         r1_bio->bios[rdisk] = read_bio;
1321
1322         read_bio->bi_iter.bi_sector = r1_bio->sector +
1323                 mirror->rdev->data_offset;
1324         read_bio->bi_end_io = raid1_end_read_request;
1325         bio_set_op_attrs(read_bio, op, do_sync);
1326         if (test_bit(FailFast, &mirror->rdev->flags) &&
1327             test_bit(R1BIO_FailFast, &r1_bio->state))
1328                 read_bio->bi_opf |= MD_FAILFAST;
1329         read_bio->bi_private = r1_bio;
1330
1331         if (mddev->gendisk)
1332                 trace_block_bio_remap(read_bio, disk_devt(mddev->gendisk),
1333                                       r1_bio->sector);
1334
1335         submit_bio_noacct(read_bio);
1336 }
1337
1338 static void raid1_write_request(struct mddev *mddev, struct bio *bio,
1339                                 int max_write_sectors)
1340 {
1341         struct r1conf *conf = mddev->private;
1342         struct r1bio *r1_bio;
1343         int i, disks;
1344         struct bitmap *bitmap = mddev->bitmap;
1345         unsigned long flags;
1346         struct md_rdev *blocked_rdev;
1347         struct blk_plug_cb *cb;
1348         struct raid1_plug_cb *plug = NULL;
1349         int first_clone;
1350         int max_sectors;
1351         bool write_behind = false;
1352
1353         if (mddev_is_clustered(mddev) &&
1354              md_cluster_ops->area_resyncing(mddev, WRITE,
1355                      bio->bi_iter.bi_sector, bio_end_sector(bio))) {
1356
1357                 DEFINE_WAIT(w);
1358                 if (bio->bi_opf & REQ_NOWAIT) {
1359                         bio_wouldblock_error(bio);
1360                         return;
1361                 }
1362                 for (;;) {
1363                         prepare_to_wait(&conf->wait_barrier,
1364                                         &w, TASK_IDLE);
1365                         if (!md_cluster_ops->area_resyncing(mddev, WRITE,
1366                                                         bio->bi_iter.bi_sector,
1367                                                         bio_end_sector(bio)))
1368                                 break;
1369                         schedule();
1370                 }
1371                 finish_wait(&conf->wait_barrier, &w);
1372         }
1373
1374         /*
1375          * Register the new request and wait if the reconstruction
1376          * thread has put up a bar for new requests.
1377          * Continue immediately if no resync is active currently.
1378          */
1379         if (!wait_barrier(conf, bio->bi_iter.bi_sector,
1380                                 bio->bi_opf & REQ_NOWAIT)) {
1381                 bio_wouldblock_error(bio);
1382                 return;
1383         }
1384
1385         r1_bio = alloc_r1bio(mddev, bio);
1386         r1_bio->sectors = max_write_sectors;
1387
1388         /* first select target devices under rcu_lock and
1389          * inc refcount on their rdev.  Record them by setting
1390          * bios[x] to bio
1391          * If there are known/acknowledged bad blocks on any device on
1392          * which we have seen a write error, we want to avoid writing those
1393          * blocks.
1394          * This potentially requires several writes to write around
1395          * the bad blocks.  Each set of writes gets it's own r1bio
1396          * with a set of bios attached.
1397          */
1398
1399         disks = conf->raid_disks * 2;
1400  retry_write:
1401         blocked_rdev = NULL;
1402         rcu_read_lock();
1403         max_sectors = r1_bio->sectors;
1404         for (i = 0;  i < disks; i++) {
1405                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1406
1407                 /*
1408                  * The write-behind io is only attempted on drives marked as
1409                  * write-mostly, which means we could allocate write behind
1410                  * bio later.
1411                  */
1412                 if (rdev && test_bit(WriteMostly, &rdev->flags))
1413                         write_behind = true;
1414
1415                 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
1416                         atomic_inc(&rdev->nr_pending);
1417                         blocked_rdev = rdev;
1418                         break;
1419                 }
1420                 r1_bio->bios[i] = NULL;
1421                 if (!rdev || test_bit(Faulty, &rdev->flags)) {
1422                         if (i < conf->raid_disks)
1423                                 set_bit(R1BIO_Degraded, &r1_bio->state);
1424                         continue;
1425                 }
1426
1427                 atomic_inc(&rdev->nr_pending);
1428                 if (test_bit(WriteErrorSeen, &rdev->flags)) {
1429                         sector_t first_bad;
1430                         int bad_sectors;
1431                         int is_bad;
1432
1433                         is_bad = is_badblock(rdev, r1_bio->sector, max_sectors,
1434                                              &first_bad, &bad_sectors);
1435                         if (is_bad < 0) {
1436                                 /* mustn't write here until the bad block is
1437                                  * acknowledged*/
1438                                 set_bit(BlockedBadBlocks, &rdev->flags);
1439                                 blocked_rdev = rdev;
1440                                 break;
1441                         }
1442                         if (is_bad && first_bad <= r1_bio->sector) {
1443                                 /* Cannot write here at all */
1444                                 bad_sectors -= (r1_bio->sector - first_bad);
1445                                 if (bad_sectors < max_sectors)
1446                                         /* mustn't write more than bad_sectors
1447                                          * to other devices yet
1448                                          */
1449                                         max_sectors = bad_sectors;
1450                                 rdev_dec_pending(rdev, mddev);
1451                                 /* We don't set R1BIO_Degraded as that
1452                                  * only applies if the disk is
1453                                  * missing, so it might be re-added,
1454                                  * and we want to know to recover this
1455                                  * chunk.
1456                                  * In this case the device is here,
1457                                  * and the fact that this chunk is not
1458                                  * in-sync is recorded in the bad
1459                                  * block log
1460                                  */
1461                                 continue;
1462                         }
1463                         if (is_bad) {
1464                                 int good_sectors = first_bad - r1_bio->sector;
1465                                 if (good_sectors < max_sectors)
1466                                         max_sectors = good_sectors;
1467                         }
1468                 }
1469                 r1_bio->bios[i] = bio;
1470         }
1471         rcu_read_unlock();
1472
1473         if (unlikely(blocked_rdev)) {
1474                 /* Wait for this device to become unblocked */
1475                 int j;
1476
1477                 for (j = 0; j < i; j++)
1478                         if (r1_bio->bios[j])
1479                                 rdev_dec_pending(conf->mirrors[j].rdev, mddev);
1480                 r1_bio->state = 0;
1481                 allow_barrier(conf, bio->bi_iter.bi_sector);
1482
1483                 if (bio->bi_opf & REQ_NOWAIT) {
1484                         bio_wouldblock_error(bio);
1485                         return;
1486                 }
1487                 raid1_log(mddev, "wait rdev %d blocked", blocked_rdev->raid_disk);
1488                 md_wait_for_blocked_rdev(blocked_rdev, mddev);
1489                 wait_barrier(conf, bio->bi_iter.bi_sector, false);
1490                 goto retry_write;
1491         }
1492
1493         /*
1494          * When using a bitmap, we may call alloc_behind_master_bio below.
1495          * alloc_behind_master_bio allocates a copy of the data payload a page
1496          * at a time and thus needs a new bio that can fit the whole payload
1497          * this bio in page sized chunks.
1498          */
1499         if (write_behind && bitmap)
1500                 max_sectors = min_t(int, max_sectors,
1501                                     BIO_MAX_VECS * (PAGE_SIZE >> 9));
1502         if (max_sectors < bio_sectors(bio)) {
1503                 struct bio *split = bio_split(bio, max_sectors,
1504                                               GFP_NOIO, &conf->bio_split);
1505                 bio_chain(split, bio);
1506                 submit_bio_noacct(bio);
1507                 bio = split;
1508                 r1_bio->master_bio = bio;
1509                 r1_bio->sectors = max_sectors;
1510         }
1511
1512         if (blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
1513                 r1_bio->start_time = bio_start_io_acct(bio);
1514         atomic_set(&r1_bio->remaining, 1);
1515         atomic_set(&r1_bio->behind_remaining, 0);
1516
1517         first_clone = 1;
1518
1519         for (i = 0; i < disks; i++) {
1520                 struct bio *mbio = NULL;
1521                 struct md_rdev *rdev = conf->mirrors[i].rdev;
1522                 if (!r1_bio->bios[i])
1523                         continue;
1524
1525                 if (first_clone) {
1526                         /* do behind I/O ?
1527                          * Not if there are too many, or cannot
1528                          * allocate memory, or a reader on WriteMostly
1529                          * is waiting for behind writes to flush */
1530                         if (bitmap &&
1531                             test_bit(WriteMostly, &rdev->flags) &&
1532                             (atomic_read(&bitmap->behind_writes)
1533                              < mddev->bitmap_info.max_write_behind) &&
1534                             !waitqueue_active(&bitmap->behind_wait)) {
1535                                 alloc_behind_master_bio(r1_bio, bio);
1536                         }
1537
1538                         md_bitmap_startwrite(bitmap, r1_bio->sector, r1_bio->sectors,
1539                                              test_bit(R1BIO_BehindIO, &r1_bio->state));
1540                         first_clone = 0;
1541                 }
1542
1543                 if (r1_bio->behind_master_bio) {
1544                         mbio = bio_alloc_clone(rdev->bdev,
1545                                                r1_bio->behind_master_bio,
1546                                                GFP_NOIO, &mddev->bio_set);
1547                         if (test_bit(CollisionCheck, &rdev->flags))
1548                                 wait_for_serialization(rdev, r1_bio);
1549                         if (test_bit(WriteMostly, &rdev->flags))
1550                                 atomic_inc(&r1_bio->behind_remaining);
1551                 } else {
1552                         mbio = bio_alloc_clone(rdev->bdev, bio, GFP_NOIO,
1553                                                &mddev->bio_set);
1554
1555                         if (mddev->serialize_policy)
1556                                 wait_for_serialization(rdev, r1_bio);
1557                 }
1558
1559                 r1_bio->bios[i] = mbio;
1560
1561                 mbio->bi_iter.bi_sector = (r1_bio->sector + rdev->data_offset);
1562                 mbio->bi_end_io = raid1_end_write_request;
1563                 mbio->bi_opf = bio_op(bio) | (bio->bi_opf & (REQ_SYNC | REQ_FUA));
1564                 if (test_bit(FailFast, &rdev->flags) &&
1565                     !test_bit(WriteMostly, &rdev->flags) &&
1566                     conf->raid_disks - mddev->degraded > 1)
1567                         mbio->bi_opf |= MD_FAILFAST;
1568                 mbio->bi_private = r1_bio;
1569
1570                 atomic_inc(&r1_bio->remaining);
1571
1572                 if (mddev->gendisk)
1573                         trace_block_bio_remap(mbio, disk_devt(mddev->gendisk),
1574                                               r1_bio->sector);
1575                 /* flush_pending_writes() needs access to the rdev so...*/
1576                 mbio->bi_bdev = (void *)rdev;
1577
1578                 cb = blk_check_plugged(raid1_unplug, mddev, sizeof(*plug));
1579                 if (cb)
1580                         plug = container_of(cb, struct raid1_plug_cb, cb);
1581                 else
1582                         plug = NULL;
1583                 if (plug) {
1584                         bio_list_add(&plug->pending, mbio);
1585                 } else {
1586                         spin_lock_irqsave(&conf->device_lock, flags);
1587                         bio_list_add(&conf->pending_bio_list, mbio);
1588                         spin_unlock_irqrestore(&conf->device_lock, flags);
1589                         md_wakeup_thread(mddev->thread);
1590                 }
1591         }
1592
1593         r1_bio_write_done(r1_bio);
1594
1595         /* In case raid1d snuck in to freeze_array */
1596         wake_up(&conf->wait_barrier);
1597 }
1598
1599 static bool raid1_make_request(struct mddev *mddev, struct bio *bio)
1600 {
1601         sector_t sectors;
1602
1603         if (unlikely(bio->bi_opf & REQ_PREFLUSH)
1604             && md_flush_request(mddev, bio))
1605                 return true;
1606
1607         /*
1608          * There is a limit to the maximum size, but
1609          * the read/write handler might find a lower limit
1610          * due to bad blocks.  To avoid multiple splits,
1611          * we pass the maximum number of sectors down
1612          * and let the lower level perform the split.
1613          */
1614         sectors = align_to_barrier_unit_end(
1615                 bio->bi_iter.bi_sector, bio_sectors(bio));
1616
1617         if (bio_data_dir(bio) == READ)
1618                 raid1_read_request(mddev, bio, sectors, NULL);
1619         else {
1620                 if (!md_write_start(mddev,bio))
1621                         return false;
1622                 raid1_write_request(mddev, bio, sectors);
1623         }
1624         return true;
1625 }
1626
1627 static void raid1_status(struct seq_file *seq, struct mddev *mddev)
1628 {
1629         struct r1conf *conf = mddev->private;
1630         int i;
1631
1632         seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1633                    conf->raid_disks - mddev->degraded);
1634         rcu_read_lock();
1635         for (i = 0; i < conf->raid_disks; i++) {
1636                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1637                 seq_printf(seq, "%s",
1638                            rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1639         }
1640         rcu_read_unlock();
1641         seq_printf(seq, "]");
1642 }
1643
1644 static void raid1_error(struct mddev *mddev, struct md_rdev *rdev)
1645 {
1646         char b[BDEVNAME_SIZE];
1647         struct r1conf *conf = mddev->private;
1648         unsigned long flags;
1649
1650         /*
1651          * If it is not operational, then we have already marked it as dead
1652          * else if it is the last working disks with "fail_last_dev == false",
1653          * ignore the error, let the next level up know.
1654          * else mark the drive as failed
1655          */
1656         spin_lock_irqsave(&conf->device_lock, flags);
1657         if (test_bit(In_sync, &rdev->flags) && !mddev->fail_last_dev
1658             && (conf->raid_disks - mddev->degraded) == 1) {
1659                 /*
1660                  * Don't fail the drive, act as though we were just a
1661                  * normal single drive.
1662                  * However don't try a recovery from this drive as
1663                  * it is very likely to fail.
1664                  */
1665                 conf->recovery_disabled = mddev->recovery_disabled;
1666                 spin_unlock_irqrestore(&conf->device_lock, flags);
1667                 return;
1668         }
1669         set_bit(Blocked, &rdev->flags);
1670         if (test_and_clear_bit(In_sync, &rdev->flags))
1671                 mddev->degraded++;
1672         set_bit(Faulty, &rdev->flags);
1673         spin_unlock_irqrestore(&conf->device_lock, flags);
1674         /*
1675          * if recovery is running, make sure it aborts.
1676          */
1677         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1678         set_mask_bits(&mddev->sb_flags, 0,
1679                       BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
1680         pr_crit("md/raid1:%s: Disk failure on %s, disabling device.\n"
1681                 "md/raid1:%s: Operation continuing on %d devices.\n",
1682                 mdname(mddev), bdevname(rdev->bdev, b),
1683                 mdname(mddev), conf->raid_disks - mddev->degraded);
1684 }
1685
1686 static void print_conf(struct r1conf *conf)
1687 {
1688         int i;
1689
1690         pr_debug("RAID1 conf printout:\n");
1691         if (!conf) {
1692                 pr_debug("(!conf)\n");
1693                 return;
1694         }
1695         pr_debug(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1696                  conf->raid_disks);
1697
1698         rcu_read_lock();
1699         for (i = 0; i < conf->raid_disks; i++) {
1700                 char b[BDEVNAME_SIZE];
1701                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1702                 if (rdev)
1703                         pr_debug(" disk %d, wo:%d, o:%d, dev:%s\n",
1704                                  i, !test_bit(In_sync, &rdev->flags),
1705                                  !test_bit(Faulty, &rdev->flags),
1706                                  bdevname(rdev->bdev,b));
1707         }
1708         rcu_read_unlock();
1709 }
1710
1711 static void close_sync(struct r1conf *conf)
1712 {
1713         int idx;
1714
1715         for (idx = 0; idx < BARRIER_BUCKETS_NR; idx++) {
1716                 _wait_barrier(conf, idx, false);
1717                 _allow_barrier(conf, idx);
1718         }
1719
1720         mempool_exit(&conf->r1buf_pool);
1721 }
1722
1723 static int raid1_spare_active(struct mddev *mddev)
1724 {
1725         int i;
1726         struct r1conf *conf = mddev->private;
1727         int count = 0;
1728         unsigned long flags;
1729
1730         /*
1731          * Find all failed disks within the RAID1 configuration
1732          * and mark them readable.
1733          * Called under mddev lock, so rcu protection not needed.
1734          * device_lock used to avoid races with raid1_end_read_request
1735          * which expects 'In_sync' flags and ->degraded to be consistent.
1736          */
1737         spin_lock_irqsave(&conf->device_lock, flags);
1738         for (i = 0; i < conf->raid_disks; i++) {
1739                 struct md_rdev *rdev = conf->mirrors[i].rdev;
1740                 struct md_rdev *repl = conf->mirrors[conf->raid_disks + i].rdev;
1741                 if (repl
1742                     && !test_bit(Candidate, &repl->flags)
1743                     && repl->recovery_offset == MaxSector
1744                     && !test_bit(Faulty, &repl->flags)
1745                     && !test_and_set_bit(In_sync, &repl->flags)) {
1746                         /* replacement has just become active */
1747                         if (!rdev ||
1748                             !test_and_clear_bit(In_sync, &rdev->flags))
1749                                 count++;
1750                         if (rdev) {
1751                                 /* Replaced device not technically
1752                                  * faulty, but we need to be sure
1753                                  * it gets removed and never re-added
1754                                  */
1755                                 set_bit(Faulty, &rdev->flags);
1756                                 sysfs_notify_dirent_safe(
1757                                         rdev->sysfs_state);
1758                         }
1759                 }
1760                 if (rdev
1761                     && rdev->recovery_offset == MaxSector
1762                     && !test_bit(Faulty, &rdev->flags)
1763                     && !test_and_set_bit(In_sync, &rdev->flags)) {
1764                         count++;
1765                         sysfs_notify_dirent_safe(rdev->sysfs_state);
1766                 }
1767         }
1768         mddev->degraded -= count;
1769         spin_unlock_irqrestore(&conf->device_lock, flags);
1770
1771         print_conf(conf);
1772         return count;
1773 }
1774
1775 static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
1776 {
1777         struct r1conf *conf = mddev->private;
1778         int err = -EEXIST;
1779         int mirror = 0;
1780         struct raid1_info *p;
1781         int first = 0;
1782         int last = conf->raid_disks - 1;
1783
1784         if (mddev->recovery_disabled == conf->recovery_disabled)
1785                 return -EBUSY;
1786
1787         if (md_integrity_add_rdev(rdev, mddev))
1788                 return -ENXIO;
1789
1790         if (rdev->raid_disk >= 0)
1791                 first = last = rdev->raid_disk;
1792
1793         /*
1794          * find the disk ... but prefer rdev->saved_raid_disk
1795          * if possible.
1796          */
1797         if (rdev->saved_raid_disk >= 0 &&
1798             rdev->saved_raid_disk >= first &&
1799             rdev->saved_raid_disk < conf->raid_disks &&
1800             conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
1801                 first = last = rdev->saved_raid_disk;
1802
1803         for (mirror = first; mirror <= last; mirror++) {
1804                 p = conf->mirrors + mirror;
1805                 if (!p->rdev) {
1806                         if (mddev->gendisk)
1807                                 disk_stack_limits(mddev->gendisk, rdev->bdev,
1808                                                   rdev->data_offset << 9);
1809
1810                         p->head_position = 0;
1811                         rdev->raid_disk = mirror;
1812                         err = 0;
1813                         /* As all devices are equivalent, we don't need a full recovery
1814                          * if this was recently any drive of the array
1815                          */
1816                         if (rdev->saved_raid_disk < 0)
1817                                 conf->fullsync = 1;
1818                         rcu_assign_pointer(p->rdev, rdev);
1819                         break;
1820                 }
1821                 if (test_bit(WantReplacement, &p->rdev->flags) &&
1822                     p[conf->raid_disks].rdev == NULL) {
1823                         /* Add this device as a replacement */
1824                         clear_bit(In_sync, &rdev->flags);
1825                         set_bit(Replacement, &rdev->flags);
1826                         rdev->raid_disk = mirror;
1827                         err = 0;
1828                         conf->fullsync = 1;
1829                         rcu_assign_pointer(p[conf->raid_disks].rdev, rdev);
1830                         break;
1831                 }
1832         }
1833         if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
1834                 blk_queue_flag_set(QUEUE_FLAG_DISCARD, mddev->queue);
1835         print_conf(conf);
1836         return err;
1837 }
1838
1839 static int raid1_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
1840 {
1841         struct r1conf *conf = mddev->private;
1842         int err = 0;
1843         int number = rdev->raid_disk;
1844         struct raid1_info *p = conf->mirrors + number;
1845
1846         if (rdev != p->rdev)
1847                 p = conf->mirrors + conf->raid_disks + number;
1848
1849         print_conf(conf);
1850         if (rdev == p->rdev) {
1851                 if (test_bit(In_sync, &rdev->flags) ||
1852                     atomic_read(&rdev->nr_pending)) {
1853                         err = -EBUSY;
1854                         goto abort;
1855                 }
1856                 /* Only remove non-faulty devices if recovery
1857                  * is not possible.
1858                  */
1859                 if (!test_bit(Faulty, &rdev->flags) &&
1860                     mddev->recovery_disabled != conf->recovery_disabled &&
1861                     mddev->degraded < conf->raid_disks) {
1862                         err = -EBUSY;
1863                         goto abort;
1864                 }
1865                 p->rdev = NULL;
1866                 if (!test_bit(RemoveSynchronized, &rdev->flags)) {
1867                         synchronize_rcu();
1868                         if (atomic_read(&rdev->nr_pending)) {
1869                                 /* lost the race, try later */
1870                                 err = -EBUSY;
1871                                 p->rdev = rdev;
1872                                 goto abort;
1873                         }
1874                 }
1875                 if (conf->mirrors[conf->raid_disks + number].rdev) {
1876                         /* We just removed a device that is being replaced.
1877                          * Move down the replacement.  We drain all IO before
1878                          * doing this to avoid confusion.
1879                          */
1880                         struct md_rdev *repl =
1881                                 conf->mirrors[conf->raid_disks + number].rdev;
1882                         freeze_array(conf, 0);
1883                         if (atomic_read(&repl->nr_pending)) {
1884                                 /* It means that some queued IO of retry_list
1885                                  * hold repl. Thus, we cannot set replacement
1886                                  * as NULL, avoiding rdev NULL pointer
1887                                  * dereference in sync_request_write and
1888                                  * handle_write_finished.
1889                                  */
1890                                 err = -EBUSY;
1891                                 unfreeze_array(conf);
1892                                 goto abort;
1893                         }
1894                         clear_bit(Replacement, &repl->flags);
1895                         p->rdev = repl;
1896                         conf->mirrors[conf->raid_disks + number].rdev = NULL;
1897                         unfreeze_array(conf);
1898                 }
1899
1900                 clear_bit(WantReplacement, &rdev->flags);
1901                 err = md_integrity_register(mddev);
1902         }
1903 abort:
1904
1905         print_conf(conf);
1906         return err;
1907 }
1908
1909 static void end_sync_read(struct bio *bio)
1910 {
1911         struct r1bio *r1_bio = get_resync_r1bio(bio);
1912
1913         update_head_pos(r1_bio->read_disk, r1_bio);
1914
1915         /*
1916          * we have read a block, now it needs to be re-written,
1917          * or re-read if the read failed.
1918          * We don't do much here, just schedule handling by raid1d
1919          */
1920         if (!bio->bi_status)
1921                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1922
1923         if (atomic_dec_and_test(&r1_bio->remaining))
1924                 reschedule_retry(r1_bio);
1925 }
1926
1927 static void abort_sync_write(struct mddev *mddev, struct r1bio *r1_bio)
1928 {
1929         sector_t sync_blocks = 0;
1930         sector_t s = r1_bio->sector;
1931         long sectors_to_go = r1_bio->sectors;
1932
1933         /* make sure these bits don't get cleared. */
1934         do {
1935                 md_bitmap_end_sync(mddev->bitmap, s, &sync_blocks, 1);
1936                 s += sync_blocks;
1937                 sectors_to_go -= sync_blocks;
1938         } while (sectors_to_go > 0);
1939 }
1940
1941 static void put_sync_write_buf(struct r1bio *r1_bio, int uptodate)
1942 {
1943         if (atomic_dec_and_test(&r1_bio->remaining)) {
1944                 struct mddev *mddev = r1_bio->mddev;
1945                 int s = r1_bio->sectors;
1946
1947                 if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
1948                     test_bit(R1BIO_WriteError, &r1_bio->state))
1949                         reschedule_retry(r1_bio);
1950                 else {
1951                         put_buf(r1_bio);
1952                         md_done_sync(mddev, s, uptodate);
1953                 }
1954         }
1955 }
1956
1957 static void end_sync_write(struct bio *bio)
1958 {
1959         int uptodate = !bio->bi_status;
1960         struct r1bio *r1_bio = get_resync_r1bio(bio);
1961         struct mddev *mddev = r1_bio->mddev;
1962         struct r1conf *conf = mddev->private;
1963         sector_t first_bad;
1964         int bad_sectors;
1965         struct md_rdev *rdev = conf->mirrors[find_bio_disk(r1_bio, bio)].rdev;
1966
1967         if (!uptodate) {
1968                 abort_sync_write(mddev, r1_bio);
1969                 set_bit(WriteErrorSeen, &rdev->flags);
1970                 if (!test_and_set_bit(WantReplacement, &rdev->flags))
1971                         set_bit(MD_RECOVERY_NEEDED, &
1972                                 mddev->recovery);
1973                 set_bit(R1BIO_WriteError, &r1_bio->state);
1974         } else if (is_badblock(rdev, r1_bio->sector, r1_bio->sectors,
1975                                &first_bad, &bad_sectors) &&
1976                    !is_badblock(conf->mirrors[r1_bio->read_disk].rdev,
1977                                 r1_bio->sector,
1978                                 r1_bio->sectors,
1979                                 &first_bad, &bad_sectors)
1980                 )
1981                 set_bit(R1BIO_MadeGood, &r1_bio->state);
1982
1983         put_sync_write_buf(r1_bio, uptodate);
1984 }
1985
1986 static int r1_sync_page_io(struct md_rdev *rdev, sector_t sector,
1987                             int sectors, struct page *page, int rw)
1988 {
1989         if (sync_page_io(rdev, sector, sectors << 9, page, rw, 0, false))
1990                 /* success */
1991                 return 1;
1992         if (rw == WRITE) {
1993                 set_bit(WriteErrorSeen, &rdev->flags);
1994                 if (!test_and_set_bit(WantReplacement,
1995                                       &rdev->flags))
1996                         set_bit(MD_RECOVERY_NEEDED, &
1997                                 rdev->mddev->recovery);
1998         }
1999         /* need to record an error - either for the block or the device */
2000         if (!rdev_set_badblocks(rdev, sector, sectors, 0))
2001                 md_error(rdev->mddev, rdev);
2002         return 0;
2003 }
2004
2005 static int fix_sync_read_error(struct r1bio *r1_bio)
2006 {
2007         /* Try some synchronous reads of other devices to get
2008          * good data, much like with normal read errors.  Only
2009          * read into the pages we already have so we don't
2010          * need to re-issue the read request.
2011          * We don't need to freeze the array, because being in an
2012          * active sync request, there is no normal IO, and
2013          * no overlapping syncs.
2014          * We don't need to check is_badblock() again as we
2015          * made sure that anything with a bad block in range
2016          * will have bi_end_io clear.
2017          */
2018         struct mddev *mddev = r1_bio->mddev;
2019         struct r1conf *conf = mddev->private;
2020         struct bio *bio = r1_bio->bios[r1_bio->read_disk];
2021         struct page **pages = get_resync_pages(bio)->pages;
2022         sector_t sect = r1_bio->sector;
2023         int sectors = r1_bio->sectors;
2024         int idx = 0;
2025         struct md_rdev *rdev;
2026
2027         rdev = conf->mirrors[r1_bio->read_disk].rdev;
2028         if (test_bit(FailFast, &rdev->flags)) {
2029                 /* Don't try recovering from here - just fail it
2030                  * ... unless it is the last working device of course */
2031                 md_error(mddev, rdev);
2032                 if (test_bit(Faulty, &rdev->flags))
2033                         /* Don't try to read from here, but make sure
2034                          * put_buf does it's thing
2035                          */
2036                         bio->bi_end_io = end_sync_write;
2037         }
2038
2039         while(sectors) {
2040                 int s = sectors;
2041                 int d = r1_bio->read_disk;
2042                 int success = 0;
2043                 int start;
2044
2045                 if (s > (PAGE_SIZE>>9))
2046                         s = PAGE_SIZE >> 9;
2047                 do {
2048                         if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
2049                                 /* No rcu protection needed here devices
2050                                  * can only be removed when no resync is
2051                                  * active, and resync is currently active
2052                                  */
2053                                 rdev = conf->mirrors[d].rdev;
2054                                 if (sync_page_io(rdev, sect, s<<9,
2055                                                  pages[idx],
2056                                                  REQ_OP_READ, 0, false)) {
2057                                         success = 1;
2058                                         break;
2059                                 }
2060                         }
2061                         d++;
2062                         if (d == conf->raid_disks * 2)
2063                                 d = 0;
2064                 } while (!success && d != r1_bio->read_disk);
2065
2066                 if (!success) {
2067                         int abort = 0;
2068                         /* Cannot read from anywhere, this block is lost.
2069                          * Record a bad block on each device.  If that doesn't
2070                          * work just disable and interrupt the recovery.
2071                          * Don't fail devices as that won't really help.
2072                          */
2073                         pr_crit_ratelimited("md/raid1:%s: %pg: unrecoverable I/O read error for block %llu\n",
2074                                             mdname(mddev), bio->bi_bdev,
2075                                             (unsigned long long)r1_bio->sector);
2076                         for (d = 0; d < conf->raid_disks * 2; d++) {
2077                                 rdev = conf->mirrors[d].rdev;
2078                                 if (!rdev || test_bit(Faulty, &rdev->flags))
2079                                         continue;
2080                                 if (!rdev_set_badblocks(rdev, sect, s, 0))
2081                                         abort = 1;
2082                         }
2083                         if (abort) {
2084                                 conf->recovery_disabled =
2085                                         mddev->recovery_disabled;
2086                                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2087                                 md_done_sync(mddev, r1_bio->sectors, 0);
2088                                 put_buf(r1_bio);
2089                                 return 0;
2090                         }
2091                         /* Try next page */
2092                         sectors -= s;
2093                         sect += s;
2094                         idx++;
2095                         continue;
2096                 }
2097
2098                 start = d;
2099                 /* write it back and re-read */
2100                 while (d != r1_bio->read_disk) {
2101                         if (d == 0)
2102                                 d = conf->raid_disks * 2;
2103                         d--;
2104                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
2105                                 continue;
2106                         rdev = conf->mirrors[d].rdev;
2107                         if (r1_sync_page_io(rdev, sect, s,
2108                                             pages[idx],
2109                                             WRITE) == 0) {
2110                                 r1_bio->bios[d]->bi_end_io = NULL;
2111                                 rdev_dec_pending(rdev, mddev);
2112                         }
2113                 }
2114                 d = start;
2115                 while (d != r1_bio->read_disk) {
2116                         if (d == 0)
2117                                 d = conf->raid_disks * 2;
2118                         d--;
2119                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
2120                                 continue;
2121                         rdev = conf->mirrors[d].rdev;
2122                         if (r1_sync_page_io(rdev, sect, s,
2123                                             pages[idx],
2124                                             READ) != 0)
2125                                 atomic_add(s, &rdev->corrected_errors);
2126                 }
2127                 sectors -= s;
2128                 sect += s;
2129                 idx ++;
2130         }
2131         set_bit(R1BIO_Uptodate, &r1_bio->state);
2132         bio->bi_status = 0;
2133         return 1;
2134 }
2135
2136 static void process_checks(struct r1bio *r1_bio)
2137 {
2138         /* We have read all readable devices.  If we haven't
2139          * got the block, then there is no hope left.
2140          * If we have, then we want to do a comparison
2141          * and skip the write if everything is the same.
2142          * If any blocks failed to read, then we need to
2143          * attempt an over-write
2144          */
2145         struct mddev *mddev = r1_bio->mddev;
2146         struct r1conf *conf = mddev->private;
2147         int primary;
2148         int i;
2149         int vcnt;
2150
2151         /* Fix variable parts of all bios */
2152         vcnt = (r1_bio->sectors + PAGE_SIZE / 512 - 1) >> (PAGE_SHIFT - 9);
2153         for (i = 0; i < conf->raid_disks * 2; i++) {
2154                 blk_status_t status;
2155                 struct bio *b = r1_bio->bios[i];
2156                 struct resync_pages *rp = get_resync_pages(b);
2157                 if (b->bi_end_io != end_sync_read)
2158                         continue;
2159                 /* fixup the bio for reuse, but preserve errno */
2160                 status = b->bi_status;
2161                 bio_reset(b, conf->mirrors[i].rdev->bdev, REQ_OP_READ);
2162                 b->bi_status = status;
2163                 b->bi_iter.bi_sector = r1_bio->sector +
2164                         conf->mirrors[i].rdev->data_offset;
2165                 b->bi_end_io = end_sync_read;
2166                 rp->raid_bio = r1_bio;
2167                 b->bi_private = rp;
2168
2169                 /* initialize bvec table again */
2170                 md_bio_reset_resync_pages(b, rp, r1_bio->sectors << 9);
2171         }
2172         for (primary = 0; primary < conf->raid_disks * 2; primary++)
2173                 if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
2174                     !r1_bio->bios[primary]->bi_status) {
2175                         r1_bio->bios[primary]->bi_end_io = NULL;
2176                         rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
2177                         break;
2178                 }
2179         r1_bio->read_disk = primary;
2180         for (i = 0; i < conf->raid_disks * 2; i++) {
2181                 int j = 0;
2182                 struct bio *pbio = r1_bio->bios[primary];
2183                 struct bio *sbio = r1_bio->bios[i];
2184                 blk_status_t status = sbio->bi_status;
2185                 struct page **ppages = get_resync_pages(pbio)->pages;
2186                 struct page **spages = get_resync_pages(sbio)->pages;
2187                 struct bio_vec *bi;
2188                 int page_len[RESYNC_PAGES] = { 0 };
2189                 struct bvec_iter_all iter_all;
2190
2191                 if (sbio->bi_end_io != end_sync_read)
2192                         continue;
2193                 /* Now we can 'fixup' the error value */
2194                 sbio->bi_status = 0;
2195
2196                 bio_for_each_segment_all(bi, sbio, iter_all)
2197                         page_len[j++] = bi->bv_len;
2198
2199                 if (!status) {
2200                         for (j = vcnt; j-- ; ) {
2201                                 if (memcmp(page_address(ppages[j]),
2202                                            page_address(spages[j]),
2203                                            page_len[j]))
2204                                         break;
2205                         }
2206                 } else
2207                         j = 0;
2208                 if (j >= 0)
2209                         atomic64_add(r1_bio->sectors, &mddev->resync_mismatches);
2210                 if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
2211                               && !status)) {
2212                         /* No need to write to this device. */
2213                         sbio->bi_end_io = NULL;
2214                         rdev_dec_pending(conf->mirrors[i].rdev, mddev);
2215                         continue;
2216                 }
2217
2218                 bio_copy_data(sbio, pbio);
2219         }
2220 }
2221
2222 static void sync_request_write(struct mddev *mddev, struct r1bio *r1_bio)
2223 {
2224         struct r1conf *conf = mddev->private;
2225         int i;
2226         int disks = conf->raid_disks * 2;
2227         struct bio *wbio;
2228
2229         if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
2230                 /* ouch - failed to read all of that. */
2231                 if (!fix_sync_read_error(r1_bio))
2232                         return;
2233
2234         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2235                 process_checks(r1_bio);
2236
2237         /*
2238          * schedule writes
2239          */
2240         atomic_set(&r1_bio->remaining, 1);
2241         for (i = 0; i < disks ; i++) {
2242                 wbio = r1_bio->bios[i];
2243                 if (wbio->bi_end_io == NULL ||
2244                     (wbio->bi_end_io == end_sync_read &&
2245                      (i == r1_bio->read_disk ||
2246                       !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
2247                         continue;
2248                 if (test_bit(Faulty, &conf->mirrors[i].rdev->flags)) {
2249                         abort_sync_write(mddev, r1_bio);
2250                         continue;
2251                 }
2252
2253                 bio_set_op_attrs(wbio, REQ_OP_WRITE, 0);
2254                 if (test_bit(FailFast, &conf->mirrors[i].rdev->flags))
2255                         wbio->bi_opf |= MD_FAILFAST;
2256
2257                 wbio->bi_end_io = end_sync_write;
2258                 atomic_inc(&r1_bio->remaining);
2259                 md_sync_acct(conf->mirrors[i].rdev->bdev, bio_sectors(wbio));
2260
2261                 submit_bio_noacct(wbio);
2262         }
2263
2264         put_sync_write_buf(r1_bio, 1);
2265 }
2266
2267 /*
2268  * This is a kernel thread which:
2269  *
2270  *      1.      Retries failed read operations on working mirrors.
2271  *      2.      Updates the raid superblock when problems encounter.
2272  *      3.      Performs writes following reads for array synchronising.
2273  */
2274
2275 static void fix_read_error(struct r1conf *conf, int read_disk,
2276                            sector_t sect, int sectors)
2277 {
2278         struct mddev *mddev = conf->mddev;
2279         while(sectors) {
2280                 int s = sectors;
2281                 int d = read_disk;
2282                 int success = 0;
2283                 int start;
2284                 struct md_rdev *rdev;
2285
2286                 if (s > (PAGE_SIZE>>9))
2287                         s = PAGE_SIZE >> 9;
2288
2289                 do {
2290                         sector_t first_bad;
2291                         int bad_sectors;
2292
2293                         rcu_read_lock();
2294                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2295                         if (rdev &&
2296                             (test_bit(In_sync, &rdev->flags) ||
2297                              (!test_bit(Faulty, &rdev->flags) &&
2298                               rdev->recovery_offset >= sect + s)) &&
2299                             is_badblock(rdev, sect, s,
2300                                         &first_bad, &bad_sectors) == 0) {
2301                                 atomic_inc(&rdev->nr_pending);
2302                                 rcu_read_unlock();
2303                                 if (sync_page_io(rdev, sect, s<<9,
2304                                          conf->tmppage, REQ_OP_READ, 0, false))
2305                                         success = 1;
2306                                 rdev_dec_pending(rdev, mddev);
2307                                 if (success)
2308                                         break;
2309                         } else
2310                                 rcu_read_unlock();
2311                         d++;
2312                         if (d == conf->raid_disks * 2)
2313                                 d = 0;
2314                 } while (!success && d != read_disk);
2315
2316                 if (!success) {
2317                         /* Cannot read from anywhere - mark it bad */
2318                         struct md_rdev *rdev = conf->mirrors[read_disk].rdev;
2319                         if (!rdev_set_badblocks(rdev, sect, s, 0))
2320                                 md_error(mddev, rdev);
2321                         break;
2322                 }
2323                 /* write it back and re-read */
2324                 start = d;
2325                 while (d != read_disk) {
2326                         if (d==0)
2327                                 d = conf->raid_disks * 2;
2328                         d--;
2329                         rcu_read_lock();
2330                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2331                         if (rdev &&
2332                             !test_bit(Faulty, &rdev->flags)) {
2333                                 atomic_inc(&rdev->nr_pending);
2334                                 rcu_read_unlock();
2335                                 r1_sync_page_io(rdev, sect, s,
2336                                                 conf->tmppage, WRITE);
2337                                 rdev_dec_pending(rdev, mddev);
2338                         } else
2339                                 rcu_read_unlock();
2340                 }
2341                 d = start;
2342                 while (d != read_disk) {
2343                         char b[BDEVNAME_SIZE];
2344                         if (d==0)
2345                                 d = conf->raid_disks * 2;
2346                         d--;
2347                         rcu_read_lock();
2348                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2349                         if (rdev &&
2350                             !test_bit(Faulty, &rdev->flags)) {
2351                                 atomic_inc(&rdev->nr_pending);
2352                                 rcu_read_unlock();
2353                                 if (r1_sync_page_io(rdev, sect, s,
2354                                                     conf->tmppage, READ)) {
2355                                         atomic_add(s, &rdev->corrected_errors);
2356                                         pr_info("md/raid1:%s: read error corrected (%d sectors at %llu on %s)\n",
2357                                                 mdname(mddev), s,
2358                                                 (unsigned long long)(sect +
2359                                                                      rdev->data_offset),
2360                                                 bdevname(rdev->bdev, b));
2361                                 }
2362                                 rdev_dec_pending(rdev, mddev);
2363                         } else
2364                                 rcu_read_unlock();
2365                 }
2366                 sectors -= s;
2367                 sect += s;
2368         }
2369 }
2370
2371 static int narrow_write_error(struct r1bio *r1_bio, int i)
2372 {
2373         struct mddev *mddev = r1_bio->mddev;
2374         struct r1conf *conf = mddev->private;
2375         struct md_rdev *rdev = conf->mirrors[i].rdev;
2376
2377         /* bio has the data to be written to device 'i' where
2378          * we just recently had a write error.
2379          * We repeatedly clone the bio and trim down to one block,
2380          * then try the write.  Where the write fails we record
2381          * a bad block.
2382          * It is conceivable that the bio doesn't exactly align with
2383          * blocks.  We must handle this somehow.
2384          *
2385          * We currently own a reference on the rdev.
2386          */
2387
2388         int block_sectors;
2389         sector_t sector;
2390         int sectors;
2391         int sect_to_write = r1_bio->sectors;
2392         int ok = 1;
2393
2394         if (rdev->badblocks.shift < 0)
2395                 return 0;
2396
2397         block_sectors = roundup(1 << rdev->badblocks.shift,
2398                                 bdev_logical_block_size(rdev->bdev) >> 9);
2399         sector = r1_bio->sector;
2400         sectors = ((sector + block_sectors)
2401                    & ~(sector_t)(block_sectors - 1))
2402                 - sector;
2403
2404         while (sect_to_write) {
2405                 struct bio *wbio;
2406                 if (sectors > sect_to_write)
2407                         sectors = sect_to_write;
2408                 /* Write at 'sector' for 'sectors'*/
2409
2410                 if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
2411                         wbio = bio_alloc_clone(rdev->bdev,
2412                                                r1_bio->behind_master_bio,
2413                                                GFP_NOIO, &mddev->bio_set);
2414                 } else {
2415                         wbio = bio_alloc_clone(rdev->bdev, r1_bio->master_bio,
2416                                                GFP_NOIO, &mddev->bio_set);
2417                 }
2418
2419                 bio_set_op_attrs(wbio, REQ_OP_WRITE, 0);
2420                 wbio->bi_iter.bi_sector = r1_bio->sector;
2421                 wbio->bi_iter.bi_size = r1_bio->sectors << 9;
2422
2423                 bio_trim(wbio, sector - r1_bio->sector, sectors);
2424                 wbio->bi_iter.bi_sector += rdev->data_offset;
2425
2426                 if (submit_bio_wait(wbio) < 0)
2427                         /* failure! */
2428                         ok = rdev_set_badblocks(rdev, sector,
2429                                                 sectors, 0)
2430                                 && ok;
2431
2432                 bio_put(wbio);
2433                 sect_to_write -= sectors;
2434                 sector += sectors;
2435                 sectors = block_sectors;
2436         }
2437         return ok;
2438 }
2439
2440 static void handle_sync_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2441 {
2442         int m;
2443         int s = r1_bio->sectors;
2444         for (m = 0; m < conf->raid_disks * 2 ; m++) {
2445                 struct md_rdev *rdev = conf->mirrors[m].rdev;
2446                 struct bio *bio = r1_bio->bios[m];
2447                 if (bio->bi_end_io == NULL)
2448                         continue;
2449                 if (!bio->bi_status &&
2450                     test_bit(R1BIO_MadeGood, &r1_bio->state)) {
2451                         rdev_clear_badblocks(rdev, r1_bio->sector, s, 0);
2452                 }
2453                 if (bio->bi_status &&
2454                     test_bit(R1BIO_WriteError, &r1_bio->state)) {
2455                         if (!rdev_set_badblocks(rdev, r1_bio->sector, s, 0))
2456                                 md_error(conf->mddev, rdev);
2457                 }
2458         }
2459         put_buf(r1_bio);
2460         md_done_sync(conf->mddev, s, 1);
2461 }
2462
2463 static void handle_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2464 {
2465         int m, idx;
2466         bool fail = false;
2467
2468         for (m = 0; m < conf->raid_disks * 2 ; m++)
2469                 if (r1_bio->bios[m] == IO_MADE_GOOD) {
2470                         struct md_rdev *rdev = conf->mirrors[m].rdev;
2471                         rdev_clear_badblocks(rdev,
2472                                              r1_bio->sector,
2473                                              r1_bio->sectors, 0);
2474                         rdev_dec_pending(rdev, conf->mddev);
2475                 } else if (r1_bio->bios[m] != NULL) {
2476                         /* This drive got a write error.  We need to
2477                          * narrow down and record precise write
2478                          * errors.
2479                          */
2480                         fail = true;
2481                         if (!narrow_write_error(r1_bio, m)) {
2482                                 md_error(conf->mddev,
2483                                          conf->mirrors[m].rdev);
2484                                 /* an I/O failed, we can't clear the bitmap */
2485                                 set_bit(R1BIO_Degraded, &r1_bio->state);
2486                         }
2487                         rdev_dec_pending(conf->mirrors[m].rdev,
2488                                          conf->mddev);
2489                 }
2490         if (fail) {
2491                 spin_lock_irq(&conf->device_lock);
2492                 list_add(&r1_bio->retry_list, &conf->bio_end_io_list);
2493                 idx = sector_to_idx(r1_bio->sector);
2494                 atomic_inc(&conf->nr_queued[idx]);
2495                 spin_unlock_irq(&conf->device_lock);
2496                 /*
2497                  * In case freeze_array() is waiting for condition
2498                  * get_unqueued_pending() == extra to be true.
2499                  */
2500                 wake_up(&conf->wait_barrier);
2501                 md_wakeup_thread(conf->mddev->thread);
2502         } else {
2503                 if (test_bit(R1BIO_WriteError, &r1_bio->state))
2504                         close_write(r1_bio);
2505                 raid_end_bio_io(r1_bio);
2506         }
2507 }
2508
2509 static void handle_read_error(struct r1conf *conf, struct r1bio *r1_bio)
2510 {
2511         struct mddev *mddev = conf->mddev;
2512         struct bio *bio;
2513         struct md_rdev *rdev;
2514
2515         clear_bit(R1BIO_ReadError, &r1_bio->state);
2516         /* we got a read error. Maybe the drive is bad.  Maybe just
2517          * the block and we can fix it.
2518          * We freeze all other IO, and try reading the block from
2519          * other devices.  When we find one, we re-write
2520          * and check it that fixes the read error.
2521          * This is all done synchronously while the array is
2522          * frozen
2523          */
2524
2525         bio = r1_bio->bios[r1_bio->read_disk];
2526         bio_put(bio);
2527         r1_bio->bios[r1_bio->read_disk] = NULL;
2528
2529         rdev = conf->mirrors[r1_bio->read_disk].rdev;
2530         if (mddev->ro == 0
2531             && !test_bit(FailFast, &rdev->flags)) {
2532                 freeze_array(conf, 1);
2533                 fix_read_error(conf, r1_bio->read_disk,
2534                                r1_bio->sector, r1_bio->sectors);
2535                 unfreeze_array(conf);
2536         } else if (mddev->ro == 0 && test_bit(FailFast, &rdev->flags)) {
2537                 md_error(mddev, rdev);
2538         } else {
2539                 r1_bio->bios[r1_bio->read_disk] = IO_BLOCKED;
2540         }
2541
2542         rdev_dec_pending(rdev, conf->mddev);
2543         allow_barrier(conf, r1_bio->sector);
2544         bio = r1_bio->master_bio;
2545
2546         /* Reuse the old r1_bio so that the IO_BLOCKED settings are preserved */
2547         r1_bio->state = 0;
2548         raid1_read_request(mddev, bio, r1_bio->sectors, r1_bio);
2549 }
2550
2551 static void raid1d(struct md_thread *thread)
2552 {
2553         struct mddev *mddev = thread->mddev;
2554         struct r1bio *r1_bio;
2555         unsigned long flags;
2556         struct r1conf *conf = mddev->private;
2557         struct list_head *head = &conf->retry_list;
2558         struct blk_plug plug;
2559         int idx;
2560
2561         md_check_recovery(mddev);
2562
2563         if (!list_empty_careful(&conf->bio_end_io_list) &&
2564             !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
2565                 LIST_HEAD(tmp);
2566                 spin_lock_irqsave(&conf->device_lock, flags);
2567                 if (!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags))
2568                         list_splice_init(&conf->bio_end_io_list, &tmp);
2569                 spin_unlock_irqrestore(&conf->device_lock, flags);
2570                 while (!list_empty(&tmp)) {
2571                         r1_bio = list_first_entry(&tmp, struct r1bio,
2572                                                   retry_list);
2573                         list_del(&r1_bio->retry_list);
2574                         idx = sector_to_idx(r1_bio->sector);
2575                         atomic_dec(&conf->nr_queued[idx]);
2576                         if (mddev->degraded)
2577                                 set_bit(R1BIO_Degraded, &r1_bio->state);
2578                         if (test_bit(R1BIO_WriteError, &r1_bio->state))
2579                                 close_write(r1_bio);
2580                         raid_end_bio_io(r1_bio);
2581                 }
2582         }
2583
2584         blk_start_plug(&plug);
2585         for (;;) {
2586
2587                 flush_pending_writes(conf);
2588
2589                 spin_lock_irqsave(&conf->device_lock, flags);
2590                 if (list_empty(head)) {
2591                         spin_unlock_irqrestore(&conf->device_lock, flags);
2592                         break;
2593                 }
2594                 r1_bio = list_entry(head->prev, struct r1bio, retry_list);
2595                 list_del(head->prev);
2596                 idx = sector_to_idx(r1_bio->sector);
2597                 atomic_dec(&conf->nr_queued[idx]);
2598                 spin_unlock_irqrestore(&conf->device_lock, flags);
2599
2600                 mddev = r1_bio->mddev;
2601                 conf = mddev->private;
2602                 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
2603                         if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2604                             test_bit(R1BIO_WriteError, &r1_bio->state))
2605                                 handle_sync_write_finished(conf, r1_bio);
2606                         else
2607                                 sync_request_write(mddev, r1_bio);
2608                 } else if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2609                            test_bit(R1BIO_WriteError, &r1_bio->state))
2610                         handle_write_finished(conf, r1_bio);
2611                 else if (test_bit(R1BIO_ReadError, &r1_bio->state))
2612                         handle_read_error(conf, r1_bio);
2613                 else
2614                         WARN_ON_ONCE(1);
2615
2616                 cond_resched();
2617                 if (mddev->sb_flags & ~(1<<MD_SB_CHANGE_PENDING))
2618                         md_check_recovery(mddev);
2619         }
2620         blk_finish_plug(&plug);
2621 }
2622
2623 static int init_resync(struct r1conf *conf)
2624 {
2625         int buffs;
2626
2627         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
2628         BUG_ON(mempool_initialized(&conf->r1buf_pool));
2629
2630         return mempool_init(&conf->r1buf_pool, buffs, r1buf_pool_alloc,
2631                             r1buf_pool_free, conf->poolinfo);
2632 }
2633
2634 static struct r1bio *raid1_alloc_init_r1buf(struct r1conf *conf)
2635 {
2636         struct r1bio *r1bio = mempool_alloc(&conf->r1buf_pool, GFP_NOIO);
2637         struct resync_pages *rps;
2638         struct bio *bio;
2639         int i;
2640
2641         for (i = conf->poolinfo->raid_disks; i--; ) {
2642                 bio = r1bio->bios[i];
2643                 rps = bio->bi_private;
2644                 bio_reset(bio, NULL, 0);
2645                 bio->bi_private = rps;
2646         }
2647         r1bio->master_bio = NULL;
2648         return r1bio;
2649 }
2650
2651 /*
2652  * perform a "sync" on one "block"
2653  *
2654  * We need to make sure that no normal I/O request - particularly write
2655  * requests - conflict with active sync requests.
2656  *
2657  * This is achieved by tracking pending requests and a 'barrier' concept
2658  * that can be installed to exclude normal IO requests.
2659  */
2660
2661 static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr,
2662                                    int *skipped)
2663 {
2664         struct r1conf *conf = mddev->private;
2665         struct r1bio *r1_bio;
2666         struct bio *bio;
2667         sector_t max_sector, nr_sectors;
2668         int disk = -1;
2669         int i;
2670         int wonly = -1;
2671         int write_targets = 0, read_targets = 0;
2672         sector_t sync_blocks;
2673         int still_degraded = 0;
2674         int good_sectors = RESYNC_SECTORS;
2675         int min_bad = 0; /* number of sectors that are bad in all devices */
2676         int idx = sector_to_idx(sector_nr);
2677         int page_idx = 0;
2678
2679         if (!mempool_initialized(&conf->r1buf_pool))
2680                 if (init_resync(conf))
2681                         return 0;
2682
2683         max_sector = mddev->dev_sectors;
2684         if (sector_nr >= max_sector) {
2685                 /* If we aborted, we need to abort the
2686                  * sync on the 'current' bitmap chunk (there will
2687                  * only be one in raid1 resync.
2688                  * We can find the current addess in mddev->curr_resync
2689                  */
2690                 if (mddev->curr_resync < max_sector) /* aborted */
2691                         md_bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
2692                                            &sync_blocks, 1);
2693                 else /* completed sync */
2694                         conf->fullsync = 0;
2695
2696                 md_bitmap_close_sync(mddev->bitmap);
2697                 close_sync(conf);
2698
2699                 if (mddev_is_clustered(mddev)) {
2700                         conf->cluster_sync_low = 0;
2701                         conf->cluster_sync_high = 0;
2702                 }
2703                 return 0;
2704         }
2705
2706         if (mddev->bitmap == NULL &&
2707             mddev->recovery_cp == MaxSector &&
2708             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
2709             conf->fullsync == 0) {
2710                 *skipped = 1;
2711                 return max_sector - sector_nr;
2712         }
2713         /* before building a request, check if we can skip these blocks..
2714          * This call the bitmap_start_sync doesn't actually record anything
2715          */
2716         if (!md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
2717             !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2718                 /* We can skip this block, and probably several more */
2719                 *skipped = 1;
2720                 return sync_blocks;
2721         }
2722
2723         /*
2724          * If there is non-resync activity waiting for a turn, then let it
2725          * though before starting on this new sync request.
2726          */
2727         if (atomic_read(&conf->nr_waiting[idx]))
2728                 schedule_timeout_uninterruptible(1);
2729
2730         /* we are incrementing sector_nr below. To be safe, we check against
2731          * sector_nr + two times RESYNC_SECTORS
2732          */
2733
2734         md_bitmap_cond_end_sync(mddev->bitmap, sector_nr,
2735                 mddev_is_clustered(mddev) && (sector_nr + 2 * RESYNC_SECTORS > conf->cluster_sync_high));
2736
2737
2738         if (raise_barrier(conf, sector_nr))
2739                 return 0;
2740
2741         r1_bio = raid1_alloc_init_r1buf(conf);
2742
2743         rcu_read_lock();
2744         /*
2745          * If we get a correctably read error during resync or recovery,
2746          * we might want to read from a different device.  So we
2747          * flag all drives that could conceivably be read from for READ,
2748          * and any others (which will be non-In_sync devices) for WRITE.
2749          * If a read fails, we try reading from something else for which READ
2750          * is OK.
2751          */
2752
2753         r1_bio->mddev = mddev;
2754         r1_bio->sector = sector_nr;
2755         r1_bio->state = 0;
2756         set_bit(R1BIO_IsSync, &r1_bio->state);
2757         /* make sure good_sectors won't go across barrier unit boundary */
2758         good_sectors = align_to_barrier_unit_end(sector_nr, good_sectors);
2759
2760         for (i = 0; i < conf->raid_disks * 2; i++) {
2761                 struct md_rdev *rdev;
2762                 bio = r1_bio->bios[i];
2763
2764                 rdev = rcu_dereference(conf->mirrors[i].rdev);
2765                 if (rdev == NULL ||
2766                     test_bit(Faulty, &rdev->flags)) {
2767                         if (i < conf->raid_disks)
2768                                 still_degraded = 1;
2769                 } else if (!test_bit(In_sync, &rdev->flags)) {
2770                         bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
2771                         bio->bi_end_io = end_sync_write;
2772                         write_targets ++;
2773                 } else {
2774                         /* may need to read from here */
2775                         sector_t first_bad = MaxSector;
2776                         int bad_sectors;
2777
2778                         if (is_badblock(rdev, sector_nr, good_sectors,
2779                                         &first_bad, &bad_sectors)) {
2780                                 if (first_bad > sector_nr)
2781                                         good_sectors = first_bad - sector_nr;
2782                                 else {
2783                                         bad_sectors -= (sector_nr - first_bad);
2784                                         if (min_bad == 0 ||
2785                                             min_bad > bad_sectors)
2786                                                 min_bad = bad_sectors;
2787                                 }
2788                         }
2789                         if (sector_nr < first_bad) {
2790                                 if (test_bit(WriteMostly, &rdev->flags)) {
2791                                         if (wonly < 0)
2792                                                 wonly = i;
2793                                 } else {
2794                                         if (disk < 0)
2795                                                 disk = i;
2796                                 }
2797                                 bio_set_op_attrs(bio, REQ_OP_READ, 0);
2798                                 bio->bi_end_io = end_sync_read;
2799                                 read_targets++;
2800                         } else if (!test_bit(WriteErrorSeen, &rdev->flags) &&
2801                                 test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
2802                                 !test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) {
2803                                 /*
2804                                  * The device is suitable for reading (InSync),
2805                                  * but has bad block(s) here. Let's try to correct them,
2806                                  * if we are doing resync or repair. Otherwise, leave
2807                                  * this device alone for this sync request.
2808                                  */
2809                                 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
2810                                 bio->bi_end_io = end_sync_write;
2811                                 write_targets++;
2812                         }
2813                 }
2814                 if (rdev && bio->bi_end_io) {
2815                         atomic_inc(&rdev->nr_pending);
2816                         bio->bi_iter.bi_sector = sector_nr + rdev->data_offset;
2817                         bio_set_dev(bio, rdev->bdev);
2818                         if (test_bit(FailFast, &rdev->flags))
2819                                 bio->bi_opf |= MD_FAILFAST;
2820                 }
2821         }
2822         rcu_read_unlock();
2823         if (disk < 0)
2824                 disk = wonly;
2825         r1_bio->read_disk = disk;
2826
2827         if (read_targets == 0 && min_bad > 0) {
2828                 /* These sectors are bad on all InSync devices, so we
2829                  * need to mark them bad on all write targets
2830                  */
2831                 int ok = 1;
2832                 for (i = 0 ; i < conf->raid_disks * 2 ; i++)
2833                         if (r1_bio->bios[i]->bi_end_io == end_sync_write) {
2834                                 struct md_rdev *rdev = conf->mirrors[i].rdev;
2835                                 ok = rdev_set_badblocks(rdev, sector_nr,
2836                                                         min_bad, 0
2837                                         ) && ok;
2838                         }
2839                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
2840                 *skipped = 1;
2841                 put_buf(r1_bio);
2842
2843                 if (!ok) {
2844                         /* Cannot record the badblocks, so need to
2845                          * abort the resync.
2846                          * If there are multiple read targets, could just
2847                          * fail the really bad ones ???
2848                          */
2849                         conf->recovery_disabled = mddev->recovery_disabled;
2850                         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2851                         return 0;
2852                 } else
2853                         return min_bad;
2854
2855         }
2856         if (min_bad > 0 && min_bad < good_sectors) {
2857                 /* only resync enough to reach the next bad->good
2858                  * transition */
2859                 good_sectors = min_bad;
2860         }
2861
2862         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
2863                 /* extra read targets are also write targets */
2864                 write_targets += read_targets-1;
2865
2866         if (write_targets == 0 || read_targets == 0) {
2867                 /* There is nowhere to write, so all non-sync
2868                  * drives must be failed - so we are finished
2869                  */
2870                 sector_t rv;
2871                 if (min_bad > 0)
2872                         max_sector = sector_nr + min_bad;
2873                 rv = max_sector - sector_nr;
2874                 *skipped = 1;
2875                 put_buf(r1_bio);
2876                 return rv;
2877         }
2878
2879         if (max_sector > mddev->resync_max)
2880                 max_sector = mddev->resync_max; /* Don't do IO beyond here */
2881         if (max_sector > sector_nr + good_sectors)
2882                 max_sector = sector_nr + good_sectors;
2883         nr_sectors = 0;
2884         sync_blocks = 0;
2885         do {
2886                 struct page *page;
2887                 int len = PAGE_SIZE;
2888                 if (sector_nr + (len>>9) > max_sector)
2889                         len = (max_sector - sector_nr) << 9;
2890                 if (len == 0)
2891                         break;
2892                 if (sync_blocks == 0) {
2893                         if (!md_bitmap_start_sync(mddev->bitmap, sector_nr,
2894                                                   &sync_blocks, still_degraded) &&
2895                             !conf->fullsync &&
2896                             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2897                                 break;
2898                         if ((len >> 9) > sync_blocks)
2899                                 len = sync_blocks<<9;
2900                 }
2901
2902                 for (i = 0 ; i < conf->raid_disks * 2; i++) {
2903                         struct resync_pages *rp;
2904
2905                         bio = r1_bio->bios[i];
2906                         rp = get_resync_pages(bio);
2907                         if (bio->bi_end_io) {
2908                                 page = resync_fetch_page(rp, page_idx);
2909
2910                                 /*
2911                                  * won't fail because the vec table is big
2912                                  * enough to hold all these pages
2913                                  */
2914                                 bio_add_page(bio, page, len, 0);
2915                         }
2916                 }
2917                 nr_sectors += len>>9;
2918                 sector_nr += len>>9;
2919                 sync_blocks -= (len>>9);
2920         } while (++page_idx < RESYNC_PAGES);
2921
2922         r1_bio->sectors = nr_sectors;
2923
2924         if (mddev_is_clustered(mddev) &&
2925                         conf->cluster_sync_high < sector_nr + nr_sectors) {
2926                 conf->cluster_sync_low = mddev->curr_resync_completed;
2927                 conf->cluster_sync_high = conf->cluster_sync_low + CLUSTER_RESYNC_WINDOW_SECTORS;
2928                 /* Send resync message */
2929                 md_cluster_ops->resync_info_update(mddev,
2930                                 conf->cluster_sync_low,
2931                                 conf->cluster_sync_high);
2932         }
2933
2934         /* For a user-requested sync, we read all readable devices and do a
2935          * compare
2936          */
2937         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2938                 atomic_set(&r1_bio->remaining, read_targets);
2939                 for (i = 0; i < conf->raid_disks * 2 && read_targets; i++) {
2940                         bio = r1_bio->bios[i];
2941                         if (bio->bi_end_io == end_sync_read) {
2942                                 read_targets--;
2943                                 md_sync_acct_bio(bio, nr_sectors);
2944                                 if (read_targets == 1)
2945                                         bio->bi_opf &= ~MD_FAILFAST;
2946                                 submit_bio_noacct(bio);
2947                         }
2948                 }
2949         } else {
2950                 atomic_set(&r1_bio->remaining, 1);
2951                 bio = r1_bio->bios[r1_bio->read_disk];
2952                 md_sync_acct_bio(bio, nr_sectors);
2953                 if (read_targets == 1)
2954                         bio->bi_opf &= ~MD_FAILFAST;
2955                 submit_bio_noacct(bio);
2956         }
2957         return nr_sectors;
2958 }
2959
2960 static sector_t raid1_size(struct mddev *mddev, sector_t sectors, int raid_disks)
2961 {
2962         if (sectors)
2963                 return sectors;
2964
2965         return mddev->dev_sectors;
2966 }
2967
2968 static struct r1conf *setup_conf(struct mddev *mddev)
2969 {
2970         struct r1conf *conf;
2971         int i;
2972         struct raid1_info *disk;
2973         struct md_rdev *rdev;
2974         int err = -ENOMEM;
2975
2976         conf = kzalloc(sizeof(struct r1conf), GFP_KERNEL);
2977         if (!conf)
2978                 goto abort;
2979
2980         conf->nr_pending = kcalloc(BARRIER_BUCKETS_NR,
2981                                    sizeof(atomic_t), GFP_KERNEL);
2982         if (!conf->nr_pending)
2983                 goto abort;
2984
2985         conf->nr_waiting = kcalloc(BARRIER_BUCKETS_NR,
2986                                    sizeof(atomic_t), GFP_KERNEL);
2987         if (!conf->nr_waiting)
2988                 goto abort;
2989
2990         conf->nr_queued = kcalloc(BARRIER_BUCKETS_NR,
2991                                   sizeof(atomic_t), GFP_KERNEL);
2992         if (!conf->nr_queued)
2993                 goto abort;
2994
2995         conf->barrier = kcalloc(BARRIER_BUCKETS_NR,
2996                                 sizeof(atomic_t), GFP_KERNEL);
2997         if (!conf->barrier)
2998                 goto abort;
2999
3000         conf->mirrors = kzalloc(array3_size(sizeof(struct raid1_info),
3001                                             mddev->raid_disks, 2),
3002                                 GFP_KERNEL);
3003         if (!conf->mirrors)
3004                 goto abort;
3005
3006         conf->tmppage = alloc_page(GFP_KERNEL);
3007         if (!conf->tmppage)
3008                 goto abort;
3009
3010         conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
3011         if (!conf->poolinfo)
3012                 goto abort;
3013         conf->poolinfo->raid_disks = mddev->raid_disks * 2;
3014         err = mempool_init(&conf->r1bio_pool, NR_RAID_BIOS, r1bio_pool_alloc,
3015                            rbio_pool_free, conf->poolinfo);
3016         if (err)
3017                 goto abort;
3018
3019         err = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
3020         if (err)
3021                 goto abort;
3022
3023         conf->poolinfo->mddev = mddev;
3024
3025         err = -EINVAL;
3026         spin_lock_init(&conf->device_lock);
3027         rdev_for_each(rdev, mddev) {
3028                 int disk_idx = rdev->raid_disk;
3029                 if (disk_idx >= mddev->raid_disks
3030                     || disk_idx < 0)
3031                         continue;
3032                 if (test_bit(Replacement, &rdev->flags))
3033                         disk = conf->mirrors + mddev->raid_disks + disk_idx;
3034                 else
3035                         disk = conf->mirrors + disk_idx;
3036
3037                 if (disk->rdev)
3038                         goto abort;
3039                 disk->rdev = rdev;
3040                 disk->head_position = 0;
3041                 disk->seq_start = MaxSector;
3042         }
3043         conf->raid_disks = mddev->raid_disks;
3044         conf->mddev = mddev;
3045         INIT_LIST_HEAD(&conf->retry_list);
3046         INIT_LIST_HEAD(&conf->bio_end_io_list);
3047
3048         spin_lock_init(&conf->resync_lock);
3049         init_waitqueue_head(&conf->wait_barrier);
3050
3051         bio_list_init(&conf->pending_bio_list);
3052         conf->recovery_disabled = mddev->recovery_disabled - 1;
3053
3054         err = -EIO;
3055         for (i = 0; i < conf->raid_disks * 2; i++) {
3056
3057                 disk = conf->mirrors + i;
3058
3059                 if (i < conf->raid_disks &&
3060                     disk[conf->raid_disks].rdev) {
3061                         /* This slot has a replacement. */
3062                         if (!disk->rdev) {
3063                                 /* No original, just make the replacement
3064                                  * a recovering spare
3065                                  */
3066                                 disk->rdev =
3067                                         disk[conf->raid_disks].rdev;
3068                                 disk[conf->raid_disks].rdev = NULL;
3069                         } else if (!test_bit(In_sync, &disk->rdev->flags))
3070                                 /* Original is not in_sync - bad */
3071                                 goto abort;
3072                 }
3073
3074                 if (!disk->rdev ||
3075                     !test_bit(In_sync, &disk->rdev->flags)) {
3076                         disk->head_position = 0;
3077                         if (disk->rdev &&
3078                             (disk->rdev->saved_raid_disk < 0))
3079                                 conf->fullsync = 1;
3080                 }
3081         }
3082
3083         err = -ENOMEM;
3084         conf->thread = md_register_thread(raid1d, mddev, "raid1");
3085         if (!conf->thread)
3086                 goto abort;
3087
3088         return conf;
3089
3090  abort:
3091         if (conf) {
3092                 mempool_exit(&conf->r1bio_pool);
3093                 kfree(conf->mirrors);
3094                 safe_put_page(conf->tmppage);
3095                 kfree(conf->poolinfo);
3096                 kfree(conf->nr_pending);
3097                 kfree(conf->nr_waiting);
3098                 kfree(conf->nr_queued);
3099                 kfree(conf->barrier);
3100                 bioset_exit(&conf->bio_split);
3101                 kfree(conf);
3102         }
3103         return ERR_PTR(err);
3104 }
3105
3106 static void raid1_free(struct mddev *mddev, void *priv);
3107 static int raid1_run(struct mddev *mddev)
3108 {
3109         struct r1conf *conf;
3110         int i;
3111         struct md_rdev *rdev;
3112         int ret;
3113         bool discard_supported = false;
3114
3115         if (mddev->level != 1) {
3116                 pr_warn("md/raid1:%s: raid level not set to mirroring (%d)\n",
3117                         mdname(mddev), mddev->level);
3118                 return -EIO;
3119         }
3120         if (mddev->reshape_position != MaxSector) {
3121                 pr_warn("md/raid1:%s: reshape_position set but not supported\n",
3122                         mdname(mddev));
3123                 return -EIO;
3124         }
3125         if (mddev_init_writes_pending(mddev) < 0)
3126                 return -ENOMEM;
3127         /*
3128          * copy the already verified devices into our private RAID1
3129          * bookkeeping area. [whatever we allocate in run(),
3130          * should be freed in raid1_free()]
3131          */
3132         if (mddev->private == NULL)
3133                 conf = setup_conf(mddev);
3134         else
3135                 conf = mddev->private;
3136
3137         if (IS_ERR(conf))
3138                 return PTR_ERR(conf);
3139
3140         if (mddev->queue)
3141                 blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
3142
3143         rdev_for_each(rdev, mddev) {
3144                 if (!mddev->gendisk)
3145                         continue;
3146                 disk_stack_limits(mddev->gendisk, rdev->bdev,
3147                                   rdev->data_offset << 9);
3148                 if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
3149                         discard_supported = true;
3150         }
3151
3152         mddev->degraded = 0;
3153         for (i = 0; i < conf->raid_disks; i++)
3154                 if (conf->mirrors[i].rdev == NULL ||
3155                     !test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
3156                     test_bit(Faulty, &conf->mirrors[i].rdev->flags))
3157                         mddev->degraded++;
3158         /*
3159          * RAID1 needs at least one disk in active
3160          */
3161         if (conf->raid_disks - mddev->degraded < 1) {
3162                 ret = -EINVAL;
3163                 goto abort;
3164         }
3165
3166         if (conf->raid_disks - mddev->degraded == 1)
3167                 mddev->recovery_cp = MaxSector;
3168
3169         if (mddev->recovery_cp != MaxSector)
3170                 pr_info("md/raid1:%s: not clean -- starting background reconstruction\n",
3171                         mdname(mddev));
3172         pr_info("md/raid1:%s: active with %d out of %d mirrors\n",
3173                 mdname(mddev), mddev->raid_disks - mddev->degraded,
3174                 mddev->raid_disks);
3175
3176         /*
3177          * Ok, everything is just fine now
3178          */
3179         mddev->thread = conf->thread;
3180         conf->thread = NULL;
3181         mddev->private = conf;
3182         set_bit(MD_FAILFAST_SUPPORTED, &mddev->flags);
3183
3184         md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
3185
3186         if (mddev->queue) {
3187                 if (discard_supported)
3188                         blk_queue_flag_set(QUEUE_FLAG_DISCARD,
3189                                                 mddev->queue);
3190                 else
3191                         blk_queue_flag_clear(QUEUE_FLAG_DISCARD,
3192                                                   mddev->queue);
3193         }
3194
3195         ret = md_integrity_register(mddev);
3196         if (ret) {
3197                 md_unregister_thread(&mddev->thread);
3198                 goto abort;
3199         }
3200         return 0;
3201
3202 abort:
3203         raid1_free(mddev, conf);
3204         return ret;
3205 }
3206
3207 static void raid1_free(struct mddev *mddev, void *priv)
3208 {
3209         struct r1conf *conf = priv;
3210
3211         mempool_exit(&conf->r1bio_pool);
3212         kfree(conf->mirrors);
3213         safe_put_page(conf->tmppage);
3214         kfree(conf->poolinfo);
3215         kfree(conf->nr_pending);
3216         kfree(conf->nr_waiting);
3217         kfree(conf->nr_queued);
3218         kfree(conf->barrier);
3219         bioset_exit(&conf->bio_split);
3220         kfree(conf);
3221 }
3222
3223 static int raid1_resize(struct mddev *mddev, sector_t sectors)
3224 {
3225         /* no resync is happening, and there is enough space
3226          * on all devices, so we can resize.
3227          * We need to make sure resync covers any new space.
3228          * If the array is shrinking we should possibly wait until
3229          * any io in the removed space completes, but it hardly seems
3230          * worth it.
3231          */
3232         sector_t newsize = raid1_size(mddev, sectors, 0);
3233         if (mddev->external_size &&
3234             mddev->array_sectors > newsize)
3235                 return -EINVAL;
3236         if (mddev->bitmap) {
3237                 int ret = md_bitmap_resize(mddev->bitmap, newsize, 0, 0);
3238                 if (ret)
3239                         return ret;
3240         }
3241         md_set_array_sectors(mddev, newsize);
3242         if (sectors > mddev->dev_sectors &&
3243             mddev->recovery_cp > mddev->dev_sectors) {
3244                 mddev->recovery_cp = mddev->dev_sectors;
3245                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3246         }
3247         mddev->dev_sectors = sectors;
3248         mddev->resync_max_sectors = sectors;
3249         return 0;
3250 }
3251
3252 static int raid1_reshape(struct mddev *mddev)
3253 {
3254         /* We need to:
3255          * 1/ resize the r1bio_pool
3256          * 2/ resize conf->mirrors
3257          *
3258          * We allocate a new r1bio_pool if we can.
3259          * Then raise a device barrier and wait until all IO stops.
3260          * Then resize conf->mirrors and swap in the new r1bio pool.
3261          *
3262          * At the same time, we "pack" the devices so that all the missing
3263          * devices have the higher raid_disk numbers.
3264          */
3265         mempool_t newpool, oldpool;
3266         struct pool_info *newpoolinfo;
3267         struct raid1_info *newmirrors;
3268         struct r1conf *conf = mddev->private;
3269         int cnt, raid_disks;
3270         unsigned long flags;
3271         int d, d2;
3272         int ret;
3273
3274         memset(&newpool, 0, sizeof(newpool));
3275         memset(&oldpool, 0, sizeof(oldpool));
3276
3277         /* Cannot change chunk_size, layout, or level */
3278         if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
3279             mddev->layout != mddev->new_layout ||
3280             mddev->level != mddev->new_level) {
3281                 mddev->new_chunk_sectors = mddev->chunk_sectors;
3282                 mddev->new_layout = mddev->layout;
3283                 mddev->new_level = mddev->level;
3284                 return -EINVAL;
3285         }
3286
3287         if (!mddev_is_clustered(mddev))
3288                 md_allow_write(mddev);
3289
3290         raid_disks = mddev->raid_disks + mddev->delta_disks;
3291
3292         if (raid_disks < conf->raid_disks) {
3293                 cnt=0;
3294                 for (d= 0; d < conf->raid_disks; d++)
3295                         if (conf->mirrors[d].rdev)
3296                                 cnt++;
3297                 if (cnt > raid_disks)
3298                         return -EBUSY;
3299         }
3300
3301         newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
3302         if (!newpoolinfo)
3303                 return -ENOMEM;
3304         newpoolinfo->mddev = mddev;
3305         newpoolinfo->raid_disks = raid_disks * 2;
3306
3307         ret = mempool_init(&newpool, NR_RAID_BIOS, r1bio_pool_alloc,
3308                            rbio_pool_free, newpoolinfo);
3309         if (ret) {
3310                 kfree(newpoolinfo);
3311                 return ret;
3312         }
3313         newmirrors = kzalloc(array3_size(sizeof(struct raid1_info),
3314                                          raid_disks, 2),
3315                              GFP_KERNEL);
3316         if (!newmirrors) {
3317                 kfree(newpoolinfo);
3318                 mempool_exit(&newpool);
3319                 return -ENOMEM;
3320         }
3321
3322         freeze_array(conf, 0);
3323
3324         /* ok, everything is stopped */
3325         oldpool = conf->r1bio_pool;
3326         conf->r1bio_pool = newpool;
3327
3328         for (d = d2 = 0; d < conf->raid_disks; d++) {
3329                 struct md_rdev *rdev = conf->mirrors[d].rdev;
3330                 if (rdev && rdev->raid_disk != d2) {
3331                         sysfs_unlink_rdev(mddev, rdev);
3332                         rdev->raid_disk = d2;
3333                         sysfs_unlink_rdev(mddev, rdev);
3334                         if (sysfs_link_rdev(mddev, rdev))
3335                                 pr_warn("md/raid1:%s: cannot register rd%d\n",
3336                                         mdname(mddev), rdev->raid_disk);
3337                 }
3338                 if (rdev)
3339                         newmirrors[d2++].rdev = rdev;
3340         }
3341         kfree(conf->mirrors);
3342         conf->mirrors = newmirrors;
3343         kfree(conf->poolinfo);
3344         conf->poolinfo = newpoolinfo;
3345
3346         spin_lock_irqsave(&conf->device_lock, flags);
3347         mddev->degraded += (raid_disks - conf->raid_disks);
3348         spin_unlock_irqrestore(&conf->device_lock, flags);
3349         conf->raid_disks = mddev->raid_disks = raid_disks;
3350         mddev->delta_disks = 0;
3351
3352         unfreeze_array(conf);
3353
3354         set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
3355         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3356         md_wakeup_thread(mddev->thread);
3357
3358         mempool_exit(&oldpool);
3359         return 0;
3360 }
3361
3362 static void raid1_quiesce(struct mddev *mddev, int quiesce)
3363 {
3364         struct r1conf *conf = mddev->private;
3365
3366         if (quiesce)
3367                 freeze_array(conf, 0);
3368         else
3369                 unfreeze_array(conf);
3370 }
3371
3372 static void *raid1_takeover(struct mddev *mddev)
3373 {
3374         /* raid1 can take over:
3375          *  raid5 with 2 devices, any layout or chunk size
3376          */
3377         if (mddev->level == 5 && mddev->raid_disks == 2) {
3378                 struct r1conf *conf;
3379                 mddev->new_level = 1;
3380                 mddev->new_layout = 0;
3381                 mddev->new_chunk_sectors = 0;
3382                 conf = setup_conf(mddev);
3383                 if (!IS_ERR(conf)) {
3384                         /* Array must appear to be quiesced */
3385                         conf->array_frozen = 1;
3386                         mddev_clear_unsupported_flags(mddev,
3387                                 UNSUPPORTED_MDDEV_FLAGS);
3388                 }
3389                 return conf;
3390         }
3391         return ERR_PTR(-EINVAL);
3392 }
3393
3394 static struct md_personality raid1_personality =
3395 {
3396         .name           = "raid1",
3397         .level          = 1,
3398         .owner          = THIS_MODULE,
3399         .make_request   = raid1_make_request,
3400         .run            = raid1_run,
3401         .free           = raid1_free,
3402         .status         = raid1_status,
3403         .error_handler  = raid1_error,
3404         .hot_add_disk   = raid1_add_disk,
3405         .hot_remove_disk= raid1_remove_disk,
3406         .spare_active   = raid1_spare_active,
3407         .sync_request   = raid1_sync_request,
3408         .resize         = raid1_resize,
3409         .size           = raid1_size,
3410         .check_reshape  = raid1_reshape,
3411         .quiesce        = raid1_quiesce,
3412         .takeover       = raid1_takeover,
3413 };
3414
3415 static int __init raid_init(void)
3416 {
3417         return register_md_personality(&raid1_personality);
3418 }
3419
3420 static void raid_exit(void)
3421 {
3422         unregister_md_personality(&raid1_personality);
3423 }
3424
3425 module_init(raid_init);
3426 module_exit(raid_exit);
3427 MODULE_LICENSE("GPL");
3428 MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
3429 MODULE_ALIAS("md-personality-3"); /* RAID1 */
3430 MODULE_ALIAS("md-raid1");
3431 MODULE_ALIAS("md-level-1");