drivers/md/raid1.c

   1 /*
   2  * raid1.c : Multiple Devices driver for Linux
   3  *
   4  * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat
   5  *
   6  * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman
   7  *
   8  * RAID-1 management functions.
   9  *
  10  * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000
  11  *
  12  * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
  13  * Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
  14  *
  15  * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support
  16  * bitmapped intelligence in resync:
  17  *
  18  *      - bitmap marked during normal i/o
  19  *      - bitmap used to skip nondirty blocks during sync
  20  *
  21  * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology:
  22  * - persistent bitmap code
  23  *
  24  * This program is free software; you can redistribute it and/or modify
  25  * it under the terms of the GNU General Public License as published by
  26  * the Free Software Foundation; either version 2, or (at your option)
  27  * any later version.
  28  *
  29  * You should have received a copy of the GNU General Public License
  30  * (for example /usr/src/linux/COPYING); if not, write to the Free
  31  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  32  */
  33
  34 #include <linux/slab.h>
  35 #include <linux/delay.h>
  36 #include <linux/blkdev.h>
  37 #include <linux/module.h>
  38 #include <linux/seq_file.h>
  39 #include <linux/ratelimit.h>
  40 #include "md.h"
  41 #include "raid1.h"
  42 #include "bitmap.h"
  43
  44 /*
  45  * Number of guaranteed r1bios in case of extreme VM load:
  46  */
  47 #define NR_RAID1_BIOS 256
  48
  49 /* when we get a read error on a read-only array, we redirect to another
  50  * device without failing the first device, or trying to over-write to
  51  * correct the read error.  To keep track of bad blocks on a per-bio
  52  * level, we store IO_BLOCKED in the appropriate 'bios' pointer
  53  */
  54 #define IO_BLOCKED ((struct bio *)1)
  55 /* When we successfully write to a known bad-block, we need to remove the
  56  * bad-block marking which must be done from process context.  So we record
  57  * the success by setting devs[n].bio to IO_MADE_GOOD
  58  */
  59 #define IO_MADE_GOOD ((struct bio *)2)
  60
  61 #define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
  62
  63 /* When there are this many requests queue to be written by
  64  * the raid1 thread, we become 'congested' to provide back-pressure
  65  * for writeback.
  66  */
  67 static int max_queued_requests = 1024;
  68
  69 static void allow_barrier(struct r1conf *conf);
  70 static void lower_barrier(struct r1conf *conf);
  71
  72 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
  73 {
  74         struct pool_info *pi = data;
  75         int size = offsetof(struct r1bio, bios[pi->raid_disks]);
  76
  77         /* allocate a r1bio with room for raid_disks entries in the bios array */
  78         return kzalloc(size, gfp_flags);
  79 }
  80
  81 static void r1bio_pool_free(void *r1_bio, void *data)
  82 {
  83         kfree(r1_bio);
  84 }
  85
  86 #define RESYNC_BLOCK_SIZE (64*1024)
  87 //#define RESYNC_BLOCK_SIZE PAGE_SIZE
  88 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
  89 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
  90 #define RESYNC_WINDOW (2048*1024)
  91
  92 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
  93 {
  94         struct pool_info *pi = data;
  95         struct r1bio *r1_bio;
  96         struct bio *bio;
  97         int need_pages;
  98         int i, j;
  99
 100         r1_bio = r1bio_pool_alloc(gfp_flags, pi);
 101         if (!r1_bio)
 102                 return NULL;
 103
 104         /*
 105          * Allocate bios : 1 for reading, n-1 for writing
 106          */
 107         for (j = pi->raid_disks ; j-- ; ) {
 108                 bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
 109                 if (!bio)
 110                         goto out_free_bio;
 111                 r1_bio->bios[j] = bio;
 112         }
 113         /*
 114          * Allocate RESYNC_PAGES data pages and attach them to
 115          * the first bio.
 116          * If this is a user-requested check/repair, allocate
 117          * RESYNC_PAGES for each bio.
 118          */
 119         if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
 120                 need_pages = pi->raid_disks;
 121         else
 122                 need_pages = 1;
 123         for (j = 0; j < need_pages; j++) {
 124                 bio = r1_bio->bios[j];
 125                 bio->bi_vcnt = RESYNC_PAGES;
 126
 127                 if (bio_alloc_pages(bio, gfp_flags))
 128                         goto out_free_pages;
 129         }
 130         /* If not user-requests, copy the page pointers to all bios */
 131         if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
 132                 for (i=0; i<RESYNC_PAGES ; i++)
 133                         for (j=1; j<pi->raid_disks; j++)
 134                                 r1_bio->bios[j]->bi_io_vec[i].bv_page =
 135                                         r1_bio->bios[0]->bi_io_vec[i].bv_page;
 136         }
 137
 138         r1_bio->master_bio = NULL;
 139
 140         return r1_bio;
 141
 142 out_free_pages:
 143         while (--j >= 0) {
 144                 struct bio_vec *bv;
 145
 146                 bio_for_each_segment_all(bv, r1_bio->bios[j], i)
 147                         __free_page(bv->bv_page);
 148         }
 149
 150 out_free_bio:
 151         while (++j < pi->raid_disks)
 152                 bio_put(r1_bio->bios[j]);
 153         r1bio_pool_free(r1_bio, data);
 154         return NULL;
 155 }
 156
 157 static void r1buf_pool_free(void *__r1_bio, void *data)
 158 {
 159         struct pool_info *pi = data;
 160         int i,j;
 161         struct r1bio *r1bio = __r1_bio;
 162
 163         for (i = 0; i < RESYNC_PAGES; i++)
 164                 for (j = pi->raid_disks; j-- ;) {
 165                         if (j == 0 ||
 166                             r1bio->bios[j]->bi_io_vec[i].bv_page !=
 167                             r1bio->bios[0]->bi_io_vec[i].bv_page)
 168                                 safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page);
 169                 }
 170         for (i=0 ; i < pi->raid_disks; i++)
 171                 bio_put(r1bio->bios[i]);
 172
 173         r1bio_pool_free(r1bio, data);
 174 }
 175
 176 static void put_all_bios(struct r1conf *conf, struct r1bio *r1_bio)
 177 {
 178         int i;
 179
 180         for (i = 0; i < conf->raid_disks * 2; i++) {
 181                 struct bio **bio = r1_bio->bios + i;
 182                 if (!BIO_SPECIAL(*bio))
 183                         bio_put(*bio);
 184                 *bio = NULL;
 185         }
 186 }
 187
 188 static void free_r1bio(struct r1bio *r1_bio)
 189 {
 190         struct r1conf *conf = r1_bio->mddev->private;
 191
 192         put_all_bios(conf, r1_bio);
 193         mempool_free(r1_bio, conf->r1bio_pool);
 194 }
 195
 196 static void put_buf(struct r1bio *r1_bio)
 197 {
 198         struct r1conf *conf = r1_bio->mddev->private;
 199         int i;
 200
 201         for (i = 0; i < conf->raid_disks * 2; i++) {
 202                 struct bio *bio = r1_bio->bios[i];
 203                 if (bio->bi_end_io)
 204                         rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
 205         }
 206
 207         mempool_free(r1_bio, conf->r1buf_pool);
 208
 209         lower_barrier(conf);
 210 }
 211
 212 static void reschedule_retry(struct r1bio *r1_bio)
 213 {
 214         unsigned long flags;
 215         struct mddev *mddev = r1_bio->mddev;
 216         struct r1conf *conf = mddev->private;
 217
 218         spin_lock_irqsave(&conf->device_lock, flags);
 219         list_add(&r1_bio->retry_list, &conf->retry_list);
 220         conf->nr_queued ++;
 221         spin_unlock_irqrestore(&conf->device_lock, flags);
 222
 223         wake_up(&conf->wait_barrier);
 224         md_wakeup_thread(mddev->thread);
 225 }
 226
 227 /*
 228  * raid_end_bio_io() is called when we have finished servicing a mirrored
 229  * operation and are ready to return a success/failure code to the buffer
 230  * cache layer.
 231  */
 232 static void call_bio_endio(struct r1bio *r1_bio)
 233 {
 234         struct bio *bio = r1_bio->master_bio;
 235         int done;
 236         struct r1conf *conf = r1_bio->mddev->private;
 237
 238         if (bio->bi_phys_segments) {
 239                 unsigned long flags;
 240                 spin_lock_irqsave(&conf->device_lock, flags);
 241                 bio->bi_phys_segments--;
 242                 done = (bio->bi_phys_segments == 0);
 243                 spin_unlock_irqrestore(&conf->device_lock, flags);
 244         } else
 245                 done = 1;
 246
 247         if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
 248                 clear_bit(BIO_UPTODATE, &bio->bi_flags);
 249         if (done) {
 250                 bio_endio(bio, 0);
 251                 /*
 252                  * Wake up any possible resync thread that waits for the device
 253                  * to go idle.
 254                  */
 255                 allow_barrier(conf);
 256         }
 257 }
 258
 259 static void raid_end_bio_io(struct r1bio *r1_bio)
 260 {
 261         struct bio *bio = r1_bio->master_bio;
 262
 263         /* if nobody has done the final endio yet, do it now */
 264         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 265                 pr_debug("raid1: sync end %s on sectors %llu-%llu\n",
 266                          (bio_data_dir(bio) == WRITE) ? "write" : "read",
 267                          (unsigned long long) bio->bi_sector,
 268                          (unsigned long long) bio->bi_sector +
 269                          bio_sectors(bio) - 1);
 270
 271                 call_bio_endio(r1_bio);
 272         }
 273         free_r1bio(r1_bio);
 274 }
 275
 276 /*
 277  * Update disk head position estimator based on IRQ completion info.
 278  */
 279 static inline void update_head_pos(int disk, struct r1bio *r1_bio)
 280 {
 281         struct r1conf *conf = r1_bio->mddev->private;
 282
 283         conf->mirrors[disk].head_position =
 284                 r1_bio->sector + (r1_bio->sectors);
 285 }
 286
 287 /*
 288  * Find the disk number which triggered given bio
 289  */
 290 static int find_bio_disk(struct r1bio *r1_bio, struct bio *bio)
 291 {
 292         int mirror;
 293         struct r1conf *conf = r1_bio->mddev->private;
 294         int raid_disks = conf->raid_disks;
 295
 296         for (mirror = 0; mirror < raid_disks * 2; mirror++)
 297                 if (r1_bio->bios[mirror] == bio)
 298                         break;
 299
 300         BUG_ON(mirror == raid_disks * 2);
 301         update_head_pos(mirror, r1_bio);
 302
 303         return mirror;
 304 }
 305
 306 static void raid1_end_read_request(struct bio *bio, int error)
 307 {
 308         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 309         struct r1bio *r1_bio = bio->bi_private;
 310         int mirror;
 311         struct r1conf *conf = r1_bio->mddev->private;
 312
 313         mirror = r1_bio->read_disk;
 314         /*
 315          * this branch is our 'one mirror IO has finished' event handler:
 316          */
 317         update_head_pos(mirror, r1_bio);
 318
 319         if (uptodate)
 320                 set_bit(R1BIO_Uptodate, &r1_bio->state);
 321         else {
 322                 /* If all other devices have failed, we want to return
 323                  * the error upwards rather than fail the last device.
 324                  * Here we redefine "uptodate" to mean "Don't want to retry"
 325                  */
 326                 unsigned long flags;
 327                 spin_lock_irqsave(&conf->device_lock, flags);
 328                 if (r1_bio->mddev->degraded == conf->raid_disks ||
 329                     (r1_bio->mddev->degraded == conf->raid_disks-1 &&
 330                      test_bit(In_sync, &conf->mirrors[mirror].rdev->flags)))
 331                         uptodate = 1;
 332                 spin_unlock_irqrestore(&conf->device_lock, flags);
 333         }
 334
 335         if (uptodate) {
 336                 raid_end_bio_io(r1_bio);
 337                 rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
 338         } else {
 339                 /*
 340                  * oops, read error:
 341                  */
 342                 char b[BDEVNAME_SIZE];
 343                 printk_ratelimited(
 344                         KERN_ERR "md/raid1:%s: %s: "
 345                         "rescheduling sector %llu\n",
 346                         mdname(conf->mddev),
 347                         bdevname(conf->mirrors[mirror].rdev->bdev,
 348                                  b),
 349                         (unsigned long long)r1_bio->sector);
 350                 set_bit(R1BIO_ReadError, &r1_bio->state);
 351                 reschedule_retry(r1_bio);
 352                 /* don't drop the reference on read_disk yet */
 353         }
 354 }
 355
 356 static void close_write(struct r1bio *r1_bio)
 357 {
 358         /* it really is the end of this request */
 359         if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
 360                 /* free extra copy of the data pages */
 361                 int i = r1_bio->behind_page_count;
 362                 while (i--)
 363                         safe_put_page(r1_bio->behind_bvecs[i].bv_page);
 364                 kfree(r1_bio->behind_bvecs);
 365                 r1_bio->behind_bvecs = NULL;
 366         }
 367         /* clear the bitmap if all writes complete successfully */
 368         bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
 369                         r1_bio->sectors,
 370                         !test_bit(R1BIO_Degraded, &r1_bio->state),
 371                         test_bit(R1BIO_BehindIO, &r1_bio->state));
 372         md_write_end(r1_bio->mddev);
 373 }
 374
 375 static void r1_bio_write_done(struct r1bio *r1_bio)
 376 {
 377         if (!atomic_dec_and_test(&r1_bio->remaining))
 378                 return;
 379
 380         if (test_bit(R1BIO_WriteError, &r1_bio->state))
 381                 reschedule_retry(r1_bio);
 382         else {
 383                 close_write(r1_bio);
 384                 if (test_bit(R1BIO_MadeGood, &r1_bio->state))
 385                         reschedule_retry(r1_bio);
 386                 else
 387                         raid_end_bio_io(r1_bio);
 388         }
 389 }
 390
 391 static void raid1_end_write_request(struct bio *bio, int error)
 392 {
 393         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 394         struct r1bio *r1_bio = bio->bi_private;
 395         int mirror, behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
 396         struct r1conf *conf = r1_bio->mddev->private;
 397         struct bio *to_put = NULL;
 398
 399         mirror = find_bio_disk(r1_bio, bio);
 400
 401         /*
 402          * 'one mirror IO has finished' event handler:
 403          */
 404         if (!uptodate) {
 405                 set_bit(WriteErrorSeen,
 406                         &conf->mirrors[mirror].rdev->flags);
 407                 if (!test_and_set_bit(WantReplacement,
 408                                       &conf->mirrors[mirror].rdev->flags))
 409                         set_bit(MD_RECOVERY_NEEDED, &
 410                                 conf->mddev->recovery);
 411
 412                 set_bit(R1BIO_WriteError, &r1_bio->state);
 413         } else {
 414                 /*
 415                  * Set R1BIO_Uptodate in our master bio, so that we
 416                  * will return a good error code for to the higher
 417                  * levels even if IO on some other mirrored buffer
 418                  * fails.
 419                  *
 420                  * The 'master' represents the composite IO operation
 421                  * to user-side. So if something waits for IO, then it
 422                  * will wait for the 'master' bio.
 423                  */
 424                 sector_t first_bad;
 425                 int bad_sectors;
 426
 427                 r1_bio->bios[mirror] = NULL;
 428                 to_put = bio;
 429                 /*
 430                  * Do not set R1BIO_Uptodate if the current device is
 431                  * rebuilding or Faulty. This is because we cannot use
 432                  * such device for properly reading the data back (we could
 433                  * potentially use it, if the current write would have felt
 434                  * before rdev->recovery_offset, but for simplicity we don't
 435                  * check this here.
 436                  */
 437                 if (test_bit(In_sync, &conf->mirrors[mirror].rdev->flags) &&
 438                     !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags))
 439                         set_bit(R1BIO_Uptodate, &r1_bio->state);
 440
 441                 /* Maybe we can clear some bad blocks. */
 442                 if (is_badblock(conf->mirrors[mirror].rdev,
 443                                 r1_bio->sector, r1_bio->sectors,
 444                                 &first_bad, &bad_sectors)) {
 445                         r1_bio->bios[mirror] = IO_MADE_GOOD;
 446                         set_bit(R1BIO_MadeGood, &r1_bio->state);
 447                 }
 448         }
 449
 450         if (behind) {
 451                 if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags))
 452                         atomic_dec(&r1_bio->behind_remaining);
 453
 454                 /*
 455                  * In behind mode, we ACK the master bio once the I/O
 456                  * has safely reached all non-writemostly
 457                  * disks. Setting the Returned bit ensures that this
 458                  * gets done only once -- we don't ever want to return
 459                  * -EIO here, instead we'll wait
 460                  */
 461                 if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
 462                     test_bit(R1BIO_Uptodate, &r1_bio->state)) {
 463                         /* Maybe we can return now */
 464                         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 465                                 struct bio *mbio = r1_bio->master_bio;
 466                                 pr_debug("raid1: behind end write sectors"
 467                                          " %llu-%llu\n",
 468                                          (unsigned long long) mbio->bi_sector,
 469                                          (unsigned long long) mbio->bi_sector +
 470                                          bio_sectors(mbio) - 1);
 471                                 call_bio_endio(r1_bio);
 472                         }
 473                 }
 474         }
 475         if (r1_bio->bios[mirror] == NULL)
 476                 rdev_dec_pending(conf->mirrors[mirror].rdev,
 477                                  conf->mddev);
 478
 479         /*
 480          * Let's see if all mirrored write operations have finished
 481          * already.
 482          */
 483         r1_bio_write_done(r1_bio);
 484
 485         if (to_put)
 486                 bio_put(to_put);
 487 }
 488
 489
 490 /*
 491  * This routine returns the disk from which the requested read should
 492  * be done. There is a per-array 'next expected sequential IO' sector
 493  * number - if this matches on the next IO then we use the last disk.
 494  * There is also a per-disk 'last know head position' sector that is
 495  * maintained from IRQ contexts, both the normal and the resync IO
 496  * completion handlers update this position correctly. If there is no
 497  * perfect sequential match then we pick the disk whose head is closest.
 498  *
 499  * If there are 2 mirrors in the same 2 devices, performance degrades
 500  * because position is mirror, not device based.
 501  *
 502  * The rdev for the device selected will have nr_pending incremented.
 503  */
 504 static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sectors)
 505 {
 506         const sector_t this_sector = r1_bio->sector;
 507         int sectors;
 508         int best_good_sectors;
 509         int best_disk, best_dist_disk, best_pending_disk;
 510         int has_nonrot_disk;
 511         int disk;
 512         sector_t best_dist;
 513         unsigned int min_pending;
 514         struct md_rdev *rdev;
 515         int choose_first;
 516         int choose_next_idle;
 517
 518         rcu_read_lock();
 519         /*
 520          * Check if we can balance. We can balance on the whole
 521          * device if no resync is going on, or below the resync window.
 522          * We take the first readable disk when above the resync window.
 523          */
 524  retry:
 525         sectors = r1_bio->sectors;
 526         best_disk = -1;
 527         best_dist_disk = -1;
 528         best_dist = MaxSector;
 529         best_pending_disk = -1;
 530         min_pending = UINT_MAX;
 531         best_good_sectors = 0;
 532         has_nonrot_disk = 0;
 533         choose_next_idle = 0;
 534
 535         if (conf->mddev->recovery_cp < MaxSector &&
 536             (this_sector + sectors >= conf->next_resync))
 537                 choose_first = 1;
 538         else
 539                 choose_first = 0;
 540
 541         for (disk = 0 ; disk < conf->raid_disks * 2 ; disk++) {
 542                 sector_t dist;
 543                 sector_t first_bad;
 544                 int bad_sectors;
 545                 unsigned int pending;
 546                 bool nonrot;
 547
 548                 rdev = rcu_dereference(conf->mirrors[disk].rdev);
 549                 if (r1_bio->bios[disk] == IO_BLOCKED
 550                     || rdev == NULL
 551                     || test_bit(Unmerged, &rdev->flags)
 552                     || test_bit(Faulty, &rdev->flags))
 553                         continue;
 554                 if (!test_bit(In_sync, &rdev->flags) &&
 555                     rdev->recovery_offset < this_sector + sectors)
 556                         continue;
 557                 if (test_bit(WriteMostly, &rdev->flags)) {
 558                         /* Don't balance among write-mostly, just
 559                          * use the first as a last resort */
 560                         if (best_dist_disk < 0) {
 561                                 if (is_badblock(rdev, this_sector, sectors,
 562                                                 &first_bad, &bad_sectors)) {
 563                                         if (first_bad < this_sector)
 564                                                 /* Cannot use this */
 565                                                 continue;
 566                                         best_good_sectors = first_bad - this_sector;
 567                                 } else
 568                                         best_good_sectors = sectors;
 569                                 best_dist_disk = disk;
 570                                 best_pending_disk = disk;
 571                         }
 572                         continue;
 573                 }
 574                 /* This is a reasonable device to use.  It might
 575                  * even be best.
 576                  */
 577                 if (is_badblock(rdev, this_sector, sectors,
 578                                 &first_bad, &bad_sectors)) {
 579                         if (best_dist < MaxSector)
 580                                 /* already have a better device */
 581                                 continue;
 582                         if (first_bad <= this_sector) {
 583                                 /* cannot read here. If this is the 'primary'
 584                                  * device, then we must not read beyond
 585                                  * bad_sectors from another device..
 586                                  */
 587                                 bad_sectors -= (this_sector - first_bad);
 588                                 if (choose_first && sectors > bad_sectors)
 589                                         sectors = bad_sectors;
 590                                 if (best_good_sectors > sectors)
 591                                         best_good_sectors = sectors;
 592
 593                         } else {
 594                                 sector_t good_sectors = first_bad - this_sector;
 595                                 if (good_sectors > best_good_sectors) {
 596                                         best_good_sectors = good_sectors;
 597                                         best_disk = disk;
 598                                 }
 599                                 if (choose_first)
 600                                         break;
 601                         }
 602                         continue;
 603                 } else
 604                         best_good_sectors = sectors;
 605
 606                 nonrot = blk_queue_nonrot(bdev_get_queue(rdev->bdev));
 607                 has_nonrot_disk |= nonrot;
 608                 pending = atomic_read(&rdev->nr_pending);
 609                 dist = abs(this_sector - conf->mirrors[disk].head_position);
 610                 if (choose_first) {
 611                         best_disk = disk;
 612                         break;
 613                 }
 614                 /* Don't change to another disk for sequential reads */
 615                 if (conf->mirrors[disk].next_seq_sect == this_sector
 616                     || dist == 0) {
 617                         int opt_iosize = bdev_io_opt(rdev->bdev) >> 9;
 618                         struct raid1_info *mirror = &conf->mirrors[disk];
 619
 620                         best_disk = disk;
 621                         /*
 622                          * If buffered sequential IO size exceeds optimal
 623                          * iosize, check if there is idle disk. If yes, choose
 624                          * the idle disk. read_balance could already choose an
 625                          * idle disk before noticing it's a sequential IO in
 626                          * this disk. This doesn't matter because this disk
 627                          * will idle, next time it will be utilized after the
 628                          * first disk has IO size exceeds optimal iosize. In
 629                          * this way, iosize of the first disk will be optimal
 630                          * iosize at least. iosize of the second disk might be
 631                          * small, but not a big deal since when the second disk
 632                          * starts IO, the first disk is likely still busy.
 633                          */
 634                         if (nonrot && opt_iosize > 0 &&
 635                             mirror->seq_start != MaxSector &&
 636                             mirror->next_seq_sect > opt_iosize &&
 637                             mirror->next_seq_sect - opt_iosize >=
 638                             mirror->seq_start) {
 639                                 choose_next_idle = 1;
 640                                 continue;
 641                         }
 642                         break;
 643                 }
 644                 /* If device is idle, use it */
 645                 if (pending == 0) {
 646                         best_disk = disk;
 647                         break;
 648                 }
 649
 650                 if (choose_next_idle)
 651                         continue;
 652
 653                 if (min_pending > pending) {
 654                         min_pending = pending;
 655                         best_pending_disk = disk;
 656                 }
 657
 658                 if (dist < best_dist) {
 659                         best_dist = dist;
 660                         best_dist_disk = disk;
 661                 }
 662         }
 663
 664         /*
 665          * If all disks are rotational, choose the closest disk. If any disk is
 666          * non-rotational, choose the disk with less pending request even the
 667          * disk is rotational, which might/might not be optimal for raids with
 668          * mixed ratation/non-rotational disks depending on workload.
 669          */
 670         if (best_disk == -1) {
 671                 if (has_nonrot_disk)
 672                         best_disk = best_pending_disk;
 673                 else
 674                         best_disk = best_dist_disk;
 675         }
 676
 677         if (best_disk >= 0) {
 678                 rdev = rcu_dereference(conf->mirrors[best_disk].rdev);
 679                 if (!rdev)
 680                         goto retry;
 681                 atomic_inc(&rdev->nr_pending);
 682                 if (test_bit(Faulty, &rdev->flags)) {
 683                         /* cannot risk returning a device that failed
 684                          * before we inc'ed nr_pending
 685                          */
 686                         rdev_dec_pending(rdev, conf->mddev);
 687                         goto retry;
 688                 }
 689                 sectors = best_good_sectors;
 690
 691                 if (conf->mirrors[best_disk].next_seq_sect != this_sector)
 692                         conf->mirrors[best_disk].seq_start = this_sector;
 693
 694                 conf->mirrors[best_disk].next_seq_sect = this_sector + sectors;
 695         }
 696         rcu_read_unlock();
 697         *max_sectors = sectors;
 698
 699         return best_disk;
 700 }
 701
 702 static int raid1_mergeable_bvec(struct request_queue *q,
 703                                 struct bvec_merge_data *bvm,
 704                                 struct bio_vec *biovec)
 705 {
 706         struct mddev *mddev = q->queuedata;
 707         struct r1conf *conf = mddev->private;
 708         sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
 709         int max = biovec->bv_len;
 710
 711         if (mddev->merge_check_needed) {
 712                 int disk;
 713                 rcu_read_lock();
 714                 for (disk = 0; disk < conf->raid_disks * 2; disk++) {
 715                         struct md_rdev *rdev = rcu_dereference(
 716                                 conf->mirrors[disk].rdev);
 717                         if (rdev && !test_bit(Faulty, &rdev->flags)) {
 718                                 struct request_queue *q =
 719                                         bdev_get_queue(rdev->bdev);
 720                                 if (q->merge_bvec_fn) {
 721                                         bvm->bi_sector = sector +
 722                                                 rdev->data_offset;
 723                                         bvm->bi_bdev = rdev->bdev;
 724                                         max = min(max, q->merge_bvec_fn(
 725                                                           q, bvm, biovec));
 726                                 }
 727                         }
 728                 }
 729                 rcu_read_unlock();
 730         }
 731         return max;
 732
 733 }
 734
 735 int md_raid1_congested(struct mddev *mddev, int bits)
 736 {
 737         struct r1conf *conf = mddev->private;
 738         int i, ret = 0;
 739
 740         if ((bits & (1 << BDI_async_congested)) &&
 741             conf->pending_count >= max_queued_requests)
 742                 return 1;
 743
 744         rcu_read_lock();
 745         for (i = 0; i < conf->raid_disks * 2; i++) {
 746                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
 747                 if (rdev && !test_bit(Faulty, &rdev->flags)) {
 748                         struct request_queue *q = bdev_get_queue(rdev->bdev);
 749
 750                         BUG_ON(!q);
 751
 752                         /* Note the '|| 1' - when read_balance prefers
 753                          * non-congested targets, it can be removed
 754                          */
 755                         if ((bits & (1<<BDI_async_congested)) || 1)
 756                                 ret |= bdi_congested(&q->backing_dev_info, bits);
 757                         else
 758                                 ret &= bdi_congested(&q->backing_dev_info, bits);
 759                 }
 760         }
 761         rcu_read_unlock();
 762         return ret;
 763 }
 764 EXPORT_SYMBOL_GPL(md_raid1_congested);
 765
 766 static int raid1_congested(void *data, int bits)
 767 {
 768         struct mddev *mddev = data;
 769
 770         return mddev_congested(mddev, bits) ||
 771                 md_raid1_congested(mddev, bits);
 772 }
 773
 774 static void flush_pending_writes(struct r1conf *conf)
 775 {
 776         /* Any writes that have been queued but are awaiting
 777          * bitmap updates get flushed here.
 778          */
 779         spin_lock_irq(&conf->device_lock);
 780
 781         if (conf->pending_bio_list.head) {
 782                 struct bio *bio;
 783                 bio = bio_list_get(&conf->pending_bio_list);
 784                 conf->pending_count = 0;
 785                 spin_unlock_irq(&conf->device_lock);
 786                 /* flush any pending bitmap writes to
 787                  * disk before proceeding w/ I/O */
 788                 bitmap_unplug(conf->mddev->bitmap);
 789                 wake_up(&conf->wait_barrier);
 790
 791                 while (bio) { /* submit pending writes */
 792                         struct bio *next = bio->bi_next;
 793                         bio->bi_next = NULL;
 794                         if (unlikely((bio->bi_rw & REQ_DISCARD) &&
 795                             !blk_queue_discard(bdev_get_queue(bio->bi_bdev))))
 796                                 /* Just ignore it */
 797                                 bio_endio(bio, 0);
 798                         else
 799                                 generic_make_request(bio);
 800                         bio = next;
 801                 }
 802         } else
 803                 spin_unlock_irq(&conf->device_lock);
 804 }
 805
 806 /* Barriers....
 807  * Sometimes we need to suspend IO while we do something else,
 808  * either some resync/recovery, or reconfigure the array.
 809  * To do this we raise a 'barrier'.
 810  * The 'barrier' is a counter that can be raised multiple times
 811  * to count how many activities are happening which preclude
 812  * normal IO.
 813  * We can only raise the barrier if there is no pending IO.
 814  * i.e. if nr_pending == 0.
 815  * We choose only to raise the barrier if no-one is waiting for the
 816  * barrier to go down.  This means that as soon as an IO request
 817  * is ready, no other operations which require a barrier will start
 818  * until the IO request has had a chance.
 819  *
 820  * So: regular IO calls 'wait_barrier'.  When that returns there
 821  *    is no backgroup IO happening,  It must arrange to call
 822  *    allow_barrier when it has finished its IO.
 823  * backgroup IO calls must call raise_barrier.  Once that returns
 824  *    there is no normal IO happeing.  It must arrange to call
 825  *    lower_barrier when the particular background IO completes.
 826  */
 827 #define RESYNC_DEPTH 32
 828
 829 static void raise_barrier(struct r1conf *conf)
 830 {
 831         spin_lock_irq(&conf->resync_lock);
 832
 833         /* Wait until no block IO is waiting */
 834         wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
 835                             conf->resync_lock);
 836
 837         /* block any new IO from starting */
 838         conf->barrier++;
 839
 840         /* Now wait for all pending IO to complete */
 841         wait_event_lock_irq(conf->wait_barrier,
 842                             !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
 843                             conf->resync_lock);
 844
 845         spin_unlock_irq(&conf->resync_lock);
 846 }
 847
 848 static void lower_barrier(struct r1conf *conf)
 849 {
 850         unsigned long flags;
 851         BUG_ON(conf->barrier <= 0);
 852         spin_lock_irqsave(&conf->resync_lock, flags);
 853         conf->barrier--;
 854         spin_unlock_irqrestore(&conf->resync_lock, flags);
 855         wake_up(&conf->wait_barrier);
 856 }
 857
 858 static void wait_barrier(struct r1conf *conf)
 859 {
 860         spin_lock_irq(&conf->resync_lock);
 861         if (conf->barrier) {
 862                 conf->nr_waiting++;
 863                 /* Wait for the barrier to drop.
 864                  * However if there are already pending
 865                  * requests (preventing the barrier from
 866                  * rising completely), and the
 867                  * pre-process bio queue isn't empty,
 868                  * then don't wait, as we need to empty
 869                  * that queue to get the nr_pending
 870                  * count down.
 871                  */
 872                 wait_event_lock_irq(conf->wait_barrier,
 873                                     !conf->barrier ||
 874                                     (conf->nr_pending &&
 875                                      current->bio_list &&
 876                                      !bio_list_empty(current->bio_list)),
 877                                     conf->resync_lock);
 878                 conf->nr_waiting--;
 879         }
 880         conf->nr_pending++;
 881         spin_unlock_irq(&conf->resync_lock);
 882 }
 883
 884 static void allow_barrier(struct r1conf *conf)
 885 {
 886         unsigned long flags;
 887         spin_lock_irqsave(&conf->resync_lock, flags);
 888         conf->nr_pending--;
 889         spin_unlock_irqrestore(&conf->resync_lock, flags);
 890         wake_up(&conf->wait_barrier);
 891 }
 892
 893 static void freeze_array(struct r1conf *conf, int extra)
 894 {
 895         /* stop syncio and normal IO and wait for everything to
 896          * go quite.
 897          * We increment barrier and nr_waiting, and then
 898          * wait until nr_pending match nr_queued+extra
 899          * This is called in the context of one normal IO request
 900          * that has failed. Thus any sync request that might be pending
 901          * will be blocked by nr_pending, and we need to wait for
 902          * pending IO requests to complete or be queued for re-try.
 903          * Thus the number queued (nr_queued) plus this request (extra)
 904          * must match the number of pending IOs (nr_pending) before
 905          * we continue.
 906          */
 907         spin_lock_irq(&conf->resync_lock);
 908         conf->barrier++;
 909         conf->nr_waiting++;
 910         wait_event_lock_irq_cmd(conf->wait_barrier,
 911                                 conf->nr_pending == conf->nr_queued+extra,
 912                                 conf->resync_lock,
 913                                 flush_pending_writes(conf));
 914         spin_unlock_irq(&conf->resync_lock);
 915 }
 916 static void unfreeze_array(struct r1conf *conf)
 917 {
 918         /* reverse the effect of the freeze */
 919         spin_lock_irq(&conf->resync_lock);
 920         conf->barrier--;
 921         conf->nr_waiting--;
 922         wake_up(&conf->wait_barrier);
 923         spin_unlock_irq(&conf->resync_lock);
 924 }
 925
 926
 927 /* duplicate the data pages for behind I/O
 928  */
 929 static void alloc_behind_pages(struct bio *bio, struct r1bio *r1_bio)
 930 {
 931         int i;
 932         struct bio_vec *bvec;
 933         struct bio_vec *bvecs = kzalloc(bio->bi_vcnt * sizeof(struct bio_vec),
 934                                         GFP_NOIO);
 935         if (unlikely(!bvecs))
 936                 return;
 937
 938         bio_for_each_segment_all(bvec, bio, i) {
 939                 bvecs[i] = *bvec;
 940                 bvecs[i].bv_page = alloc_page(GFP_NOIO);
 941                 if (unlikely(!bvecs[i].bv_page))
 942                         goto do_sync_io;
 943                 memcpy(kmap(bvecs[i].bv_page) + bvec->bv_offset,
 944                        kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
 945                 kunmap(bvecs[i].bv_page);
 946                 kunmap(bvec->bv_page);
 947         }
 948         r1_bio->behind_bvecs = bvecs;
 949         r1_bio->behind_page_count = bio->bi_vcnt;
 950         set_bit(R1BIO_BehindIO, &r1_bio->state);
 951         return;
 952
 953 do_sync_io:
 954         for (i = 0; i < bio->bi_vcnt; i++)
 955                 if (bvecs[i].bv_page)
 956                         put_page(bvecs[i].bv_page);
 957         kfree(bvecs);
 958         pr_debug("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
 959 }
 960
 961 struct raid1_plug_cb {
 962         struct blk_plug_cb      cb;
 963         struct bio_list         pending;
 964         int                     pending_cnt;
 965 };
 966
 967 static void raid1_unplug(struct blk_plug_cb *cb, bool from_schedule)
 968 {
 969         struct raid1_plug_cb *plug = container_of(cb, struct raid1_plug_cb,
 970                                                   cb);
 971         struct mddev *mddev = plug->cb.data;
 972         struct r1conf *conf = mddev->private;
 973         struct bio *bio;
 974
 975         if (from_schedule || current->bio_list) {
 976                 spin_lock_irq(&conf->device_lock);
 977                 bio_list_merge(&conf->pending_bio_list, &plug->pending);
 978                 conf->pending_count += plug->pending_cnt;
 979                 spin_unlock_irq(&conf->device_lock);
 980                 wake_up(&conf->wait_barrier);
 981                 md_wakeup_thread(mddev->thread);
 982                 kfree(plug);
 983                 return;
 984         }
 985
 986         /* we aren't scheduling, so we can do the write-out directly. */
 987         bio = bio_list_get(&plug->pending);
 988         bitmap_unplug(mddev->bitmap);
 989         wake_up(&conf->wait_barrier);
 990
 991         while (bio) { /* submit pending writes */
 992                 struct bio *next = bio->bi_next;
 993                 bio->bi_next = NULL;
 994                 if (unlikely((bio->bi_rw & REQ_DISCARD) &&
 995                     !blk_queue_discard(bdev_get_queue(bio->bi_bdev))))
 996                         /* Just ignore it */
 997                         bio_endio(bio, 0);
 998                 else
 999                         generic_make_request(bio);
1000                 bio = next;
1001         }
1002         kfree(plug);
1003 }
1004
1005 static void make_request(struct mddev *mddev, struct bio * bio)
1006 {
1007         struct r1conf *conf = mddev->private;
1008         struct raid1_info *mirror;
1009         struct r1bio *r1_bio;
1010         struct bio *read_bio;
1011         int i, disks;
1012         struct bitmap *bitmap;
1013         unsigned long flags;
1014         const int rw = bio_data_dir(bio);
1015         const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
1016         const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA));
1017         const unsigned long do_discard = (bio->bi_rw
1018                                           & (REQ_DISCARD | REQ_SECURE));
1019         const unsigned long do_same = (bio->bi_rw & REQ_WRITE_SAME);
1020         struct md_rdev *blocked_rdev;
1021         struct blk_plug_cb *cb;
1022         struct raid1_plug_cb *plug = NULL;
1023         int first_clone;
1024         int sectors_handled;
1025         int max_sectors;
1026
1027         /*
1028          * Register the new request and wait if the reconstruction
1029          * thread has put up a bar for new requests.
1030          * Continue immediately if no resync is active currently.
1031          */
1032
1033         md_write_start(mddev, bio); /* wait on superblock update early */
1034
1035         if (bio_data_dir(bio) == WRITE &&
1036             bio_end_sector(bio) > mddev->suspend_lo &&
1037             bio->bi_sector < mddev->suspend_hi) {
1038                 /* As the suspend_* range is controlled by
1039                  * userspace, we want an interruptible
1040                  * wait.
1041                  */
1042                 DEFINE_WAIT(w);
1043                 for (;;) {
1044                         flush_signals(current);
1045                         prepare_to_wait(&conf->wait_barrier,
1046                                         &w, TASK_INTERRUPTIBLE);
1047                         if (bio_end_sector(bio) <= mddev->suspend_lo ||
1048                             bio->bi_sector >= mddev->suspend_hi)
1049                                 break;
1050                         schedule();
1051                 }
1052                 finish_wait(&conf->wait_barrier, &w);
1053         }
1054
1055         wait_barrier(conf);
1056
1057         bitmap = mddev->bitmap;
1058
1059         /*
1060          * make_request() can abort the operation when READA is being
1061          * used and no empty request is available.
1062          *
1063          */
1064         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1065
1066         r1_bio->master_bio = bio;
1067         r1_bio->sectors = bio_sectors(bio);
1068         r1_bio->state = 0;
1069         r1_bio->mddev = mddev;
1070         r1_bio->sector = bio->bi_sector;
1071
1072         /* We might need to issue multiple reads to different
1073          * devices if there are bad blocks around, so we keep
1074          * track of the number of reads in bio->bi_phys_segments.
1075          * If this is 0, there is only one r1_bio and no locking
1076          * will be needed when requests complete.  If it is
1077          * non-zero, then it is the number of not-completed requests.
1078          */
1079         bio->bi_phys_segments = 0;
1080         clear_bit(BIO_SEG_VALID, &bio->bi_flags);
1081
1082         if (rw == READ) {
1083                 /*
1084                  * read balancing logic:
1085                  */
1086                 int rdisk;
1087
1088 read_again:
1089                 rdisk = read_balance(conf, r1_bio, &max_sectors);
1090
1091                 if (rdisk < 0) {
1092                         /* couldn't find anywhere to read from */
1093                         raid_end_bio_io(r1_bio);
1094                         return;
1095                 }
1096                 mirror = conf->mirrors + rdisk;
1097
1098                 if (test_bit(WriteMostly, &mirror->rdev->flags) &&
1099                     bitmap) {
1100                         /* Reading from a write-mostly device must
1101                          * take care not to over-take any writes
1102                          * that are 'behind'
1103                          */
1104                         wait_event(bitmap->behind_wait,
1105                                    atomic_read(&bitmap->behind_writes) == 0);
1106                 }
1107                 r1_bio->read_disk = rdisk;
1108
1109                 read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1110                 md_trim_bio(read_bio, r1_bio->sector - bio->bi_sector,
1111                             max_sectors);
1112
1113                 r1_bio->bios[rdisk] = read_bio;
1114
1115                 read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
1116                 read_bio->bi_bdev = mirror->rdev->bdev;
1117                 read_bio->bi_end_io = raid1_end_read_request;
1118                 read_bio->bi_rw = READ | do_sync;
1119                 read_bio->bi_private = r1_bio;
1120
1121                 if (max_sectors < r1_bio->sectors) {
1122                         /* could not read all from this device, so we will
1123                          * need another r1_bio.
1124                          */
1125
1126                         sectors_handled = (r1_bio->sector + max_sectors
1127                                            - bio->bi_sector);
1128                         r1_bio->sectors = max_sectors;
1129                         spin_lock_irq(&conf->device_lock);
1130                         if (bio->bi_phys_segments == 0)
1131                                 bio->bi_phys_segments = 2;
1132                         else
1133                                 bio->bi_phys_segments++;
1134                         spin_unlock_irq(&conf->device_lock);
1135                         /* Cannot call generic_make_request directly
1136                          * as that will be queued in __make_request
1137                          * and subsequent mempool_alloc might block waiting
1138                          * for it.  So hand bio over to raid1d.
1139                          */
1140                         reschedule_retry(r1_bio);
1141
1142                         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1143
1144                         r1_bio->master_bio = bio;
1145                         r1_bio->sectors = bio_sectors(bio) - sectors_handled;
1146                         r1_bio->state = 0;
1147                         r1_bio->mddev = mddev;
1148                         r1_bio->sector = bio->bi_sector + sectors_handled;
1149                         goto read_again;
1150                 } else
1151                         generic_make_request(read_bio);
1152                 return;
1153         }
1154
1155         /*
1156          * WRITE:
1157          */
1158         if (conf->pending_count >= max_queued_requests) {
1159                 md_wakeup_thread(mddev->thread);
1160                 wait_event(conf->wait_barrier,
1161                            conf->pending_count < max_queued_requests);
1162         }
1163         /* first select target devices under rcu_lock and
1164          * inc refcount on their rdev.  Record them by setting
1165          * bios[x] to bio
1166          * If there are known/acknowledged bad blocks on any device on
1167          * which we have seen a write error, we want to avoid writing those
1168          * blocks.
1169          * This potentially requires several writes to write around
1170          * the bad blocks.  Each set of writes gets it's own r1bio
1171          * with a set of bios attached.
1172          */
1173
1174         disks = conf->raid_disks * 2;
1175  retry_write:
1176         blocked_rdev = NULL;
1177         rcu_read_lock();
1178         max_sectors = r1_bio->sectors;
1179         for (i = 0;  i < disks; i++) {
1180                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1181                 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
1182                         atomic_inc(&rdev->nr_pending);
1183                         blocked_rdev = rdev;
1184                         break;
1185                 }
1186                 r1_bio->bios[i] = NULL;
1187                 if (!rdev || test_bit(Faulty, &rdev->flags)
1188                     || test_bit(Unmerged, &rdev->flags)) {
1189                         if (i < conf->raid_disks)
1190                                 set_bit(R1BIO_Degraded, &r1_bio->state);
1191                         continue;
1192                 }
1193
1194                 atomic_inc(&rdev->nr_pending);
1195                 if (test_bit(WriteErrorSeen, &rdev->flags)) {
1196                         sector_t first_bad;
1197                         int bad_sectors;
1198                         int is_bad;
1199
1200                         is_bad = is_badblock(rdev, r1_bio->sector,
1201                                              max_sectors,
1202                                              &first_bad, &bad_sectors);
1203                         if (is_bad < 0) {
1204                                 /* mustn't write here until the bad block is
1205                                  * acknowledged*/
1206                                 set_bit(BlockedBadBlocks, &rdev->flags);
1207                                 blocked_rdev = rdev;
1208                                 break;
1209                         }
1210                         if (is_bad && first_bad <= r1_bio->sector) {
1211                                 /* Cannot write here at all */
1212                                 bad_sectors -= (r1_bio->sector - first_bad);
1213                                 if (bad_sectors < max_sectors)
1214                                         /* mustn't write more than bad_sectors
1215                                          * to other devices yet
1216                                          */
1217                                         max_sectors = bad_sectors;
1218                                 rdev_dec_pending(rdev, mddev);
1219                                 /* We don't set R1BIO_Degraded as that
1220                                  * only applies if the disk is
1221                                  * missing, so it might be re-added,
1222                                  * and we want to know to recover this
1223                                  * chunk.
1224                                  * In this case the device is here,
1225                                  * and the fact that this chunk is not
1226                                  * in-sync is recorded in the bad
1227                                  * block log
1228                                  */
1229                                 continue;
1230                         }
1231                         if (is_bad) {
1232                                 int good_sectors = first_bad - r1_bio->sector;
1233                                 if (good_sectors < max_sectors)
1234                                         max_sectors = good_sectors;
1235                         }
1236                 }
1237                 r1_bio->bios[i] = bio;
1238         }
1239         rcu_read_unlock();
1240
1241         if (unlikely(blocked_rdev)) {
1242                 /* Wait for this device to become unblocked */
1243                 int j;
1244
1245                 for (j = 0; j < i; j++)
1246                         if (r1_bio->bios[j])
1247                                 rdev_dec_pending(conf->mirrors[j].rdev, mddev);
1248                 r1_bio->state = 0;
1249                 allow_barrier(conf);
1250                 md_wait_for_blocked_rdev(blocked_rdev, mddev);
1251                 wait_barrier(conf);
1252                 goto retry_write;
1253         }
1254
1255         if (max_sectors < r1_bio->sectors) {
1256                 /* We are splitting this write into multiple parts, so
1257                  * we need to prepare for allocating another r1_bio.
1258                  */
1259                 r1_bio->sectors = max_sectors;
1260                 spin_lock_irq(&conf->device_lock);
1261                 if (bio->bi_phys_segments == 0)
1262                         bio->bi_phys_segments = 2;
1263                 else
1264                         bio->bi_phys_segments++;
1265                 spin_unlock_irq(&conf->device_lock);
1266         }
1267         sectors_handled = r1_bio->sector + max_sectors - bio->bi_sector;
1268
1269         atomic_set(&r1_bio->remaining, 1);
1270         atomic_set(&r1_bio->behind_remaining, 0);
1271
1272         first_clone = 1;
1273         for (i = 0; i < disks; i++) {
1274                 struct bio *mbio;
1275                 if (!r1_bio->bios[i])
1276                         continue;
1277
1278                 mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1279                 md_trim_bio(mbio, r1_bio->sector - bio->bi_sector, max_sectors);
1280
1281                 if (first_clone) {
1282                         /* do behind I/O ?
1283                          * Not if there are too many, or cannot
1284                          * allocate memory, or a reader on WriteMostly
1285                          * is waiting for behind writes to flush */
1286                         if (bitmap &&
1287                             (atomic_read(&bitmap->behind_writes)
1288                              < mddev->bitmap_info.max_write_behind) &&
1289                             !waitqueue_active(&bitmap->behind_wait))
1290                                 alloc_behind_pages(mbio, r1_bio);
1291
1292                         bitmap_startwrite(bitmap, r1_bio->sector,
1293                                           r1_bio->sectors,
1294                                           test_bit(R1BIO_BehindIO,
1295                                                    &r1_bio->state));
1296                         first_clone = 0;
1297                 }
1298                 if (r1_bio->behind_bvecs) {
1299                         struct bio_vec *bvec;
1300                         int j;
1301
1302                         /*
1303                          * We trimmed the bio, so _all is legit
1304                          */
1305                         bio_for_each_segment_all(bvec, mbio, j)
1306                                 bvec->bv_page = r1_bio->behind_bvecs[j].bv_page;
1307                         if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
1308                                 atomic_inc(&r1_bio->behind_remaining);
1309                 }
1310
1311                 r1_bio->bios[i] = mbio;
1312
1313                 mbio->bi_sector = (r1_bio->sector +
1314                                    conf->mirrors[i].rdev->data_offset);
1315                 mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1316                 mbio->bi_end_io = raid1_end_write_request;
1317                 mbio->bi_rw =
1318                         WRITE | do_flush_fua | do_sync | do_discard | do_same;
1319                 mbio->bi_private = r1_bio;
1320
1321                 atomic_inc(&r1_bio->remaining);
1322
1323                 cb = blk_check_plugged(raid1_unplug, mddev, sizeof(*plug));
1324                 if (cb)
1325                         plug = container_of(cb, struct raid1_plug_cb, cb);
1326                 else
1327                         plug = NULL;
1328                 spin_lock_irqsave(&conf->device_lock, flags);
1329                 if (plug) {
1330                         bio_list_add(&plug->pending, mbio);
1331                         plug->pending_cnt++;
1332                 } else {
1333                         bio_list_add(&conf->pending_bio_list, mbio);
1334                         conf->pending_count++;
1335                 }
1336                 spin_unlock_irqrestore(&conf->device_lock, flags);
1337                 if (!plug)
1338                         md_wakeup_thread(mddev->thread);
1339         }
1340         /* Mustn't call r1_bio_write_done before this next test,
1341          * as it could result in the bio being freed.
1342          */
1343         if (sectors_handled < bio_sectors(bio)) {
1344                 r1_bio_write_done(r1_bio);
1345                 /* We need another r1_bio.  It has already been counted
1346                  * in bio->bi_phys_segments
1347                  */
1348                 r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1349                 r1_bio->master_bio = bio;
1350                 r1_bio->sectors = bio_sectors(bio) - sectors_handled;
1351                 r1_bio->state = 0;
1352                 r1_bio->mddev = mddev;
1353                 r1_bio->sector = bio->bi_sector + sectors_handled;
1354                 goto retry_write;
1355         }
1356
1357         r1_bio_write_done(r1_bio);
1358
1359         /* In case raid1d snuck in to freeze_array */
1360         wake_up(&conf->wait_barrier);
1361 }
1362
1363 static void status(struct seq_file *seq, struct mddev *mddev)
1364 {
1365         struct r1conf *conf = mddev->private;
1366         int i;
1367
1368         seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1369                    conf->raid_disks - mddev->degraded);
1370         rcu_read_lock();
1371         for (i = 0; i < conf->raid_disks; i++) {
1372                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1373                 seq_printf(seq, "%s",
1374                            rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1375         }
1376         rcu_read_unlock();
1377         seq_printf(seq, "]");
1378 }
1379
1380
1381 static void error(struct mddev *mddev, struct md_rdev *rdev)
1382 {
1383         char b[BDEVNAME_SIZE];
1384         struct r1conf *conf = mddev->private;
1385         unsigned long flags;
1386
1387         /*
1388          * If it is not operational, then we have already marked it as dead
1389          * else if it is the last working disks, ignore the error, let the
1390          * next level up know.
1391          * else mark the drive as failed
1392          */
1393         if (test_bit(In_sync, &rdev->flags)
1394             && (conf->raid_disks - mddev->degraded) == 1) {
1395                 /*
1396                  * Don't fail the drive, act as though we were just a
1397                  * normal single drive.
1398                  * However don't try a recovery from this drive as
1399                  * it is very likely to fail.
1400                  */
1401                 conf->recovery_disabled = mddev->recovery_disabled;
1402                 return;
1403         }
1404         set_bit(Blocked, &rdev->flags);
1405         spin_lock_irqsave(&conf->device_lock, flags);
1406         if (test_and_clear_bit(In_sync, &rdev->flags)) {
1407                 mddev->degraded++;
1408                 set_bit(Faulty, &rdev->flags);
1409         } else
1410                 set_bit(Faulty, &rdev->flags);
1411         spin_unlock_irqrestore(&conf->device_lock, flags);
1412         /*
1413          * if recovery is running, make sure it aborts.
1414          */
1415         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1416         set_bit(MD_CHANGE_DEVS, &mddev->flags);
1417         printk(KERN_ALERT
1418                "md/raid1:%s: Disk failure on %s, disabling device.\n"
1419                "md/raid1:%s: Operation continuing on %d devices.\n",
1420                mdname(mddev), bdevname(rdev->bdev, b),
1421                mdname(mddev), conf->raid_disks - mddev->degraded);
1422 }
1423
1424 static void print_conf(struct r1conf *conf)
1425 {
1426         int i;
1427
1428         printk(KERN_DEBUG "RAID1 conf printout:\n");
1429         if (!conf) {
1430                 printk(KERN_DEBUG "(!conf)\n");
1431                 return;
1432         }
1433         printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1434                 conf->raid_disks);
1435
1436         rcu_read_lock();
1437         for (i = 0; i < conf->raid_disks; i++) {
1438                 char b[BDEVNAME_SIZE];
1439                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1440                 if (rdev)
1441                         printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
1442                                i, !test_bit(In_sync, &rdev->flags),
1443                                !test_bit(Faulty, &rdev->flags),
1444                                bdevname(rdev->bdev,b));
1445         }
1446         rcu_read_unlock();
1447 }
1448
1449 static void close_sync(struct r1conf *conf)
1450 {
1451         wait_barrier(conf);
1452         allow_barrier(conf);
1453
1454         mempool_destroy(conf->r1buf_pool);
1455         conf->r1buf_pool = NULL;
1456 }
1457
1458 static int raid1_spare_active(struct mddev *mddev)
1459 {
1460         int i;
1461         struct r1conf *conf = mddev->private;
1462         int count = 0;
1463         unsigned long flags;
1464
1465         /*
1466          * Find all failed disks within the RAID1 configuration
1467          * and mark them readable.
1468          * Called under mddev lock, so rcu protection not needed.
1469          * device_lock used to avoid races with raid1_end_read_request
1470          * which expects 'In_sync' flags and ->degraded to be consistent.
1471          */
1472         spin_lock_irqsave(&conf->device_lock, flags);
1473         for (i = 0; i < conf->raid_disks; i++) {
1474                 struct md_rdev *rdev = conf->mirrors[i].rdev;
1475                 struct md_rdev *repl = conf->mirrors[conf->raid_disks + i].rdev;
1476                 if (repl
1477                     && repl->recovery_offset == MaxSector
1478                     && !test_bit(Faulty, &repl->flags)
1479                     && !test_and_set_bit(In_sync, &repl->flags)) {
1480                         /* replacement has just become active */
1481                         if (!rdev ||
1482                             !test_and_clear_bit(In_sync, &rdev->flags))
1483                                 count++;
1484                         if (rdev) {
1485                                 /* Replaced device not technically
1486                                  * faulty, but we need to be sure
1487                                  * it gets removed and never re-added
1488                                  */
1489                                 set_bit(Faulty, &rdev->flags);
1490                                 sysfs_notify_dirent_safe(
1491                                         rdev->sysfs_state);
1492                         }
1493                 }
1494                 if (rdev
1495                     && rdev->recovery_offset == MaxSector
1496                     && !test_bit(Faulty, &rdev->flags)
1497                     && !test_and_set_bit(In_sync, &rdev->flags)) {
1498                         count++;
1499                         sysfs_notify_dirent_safe(rdev->sysfs_state);
1500                 }
1501         }
1502         mddev->degraded -= count;
1503         spin_unlock_irqrestore(&conf->device_lock, flags);
1504
1505         print_conf(conf);
1506         return count;
1507 }
1508
1509
1510 static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
1511 {
1512         struct r1conf *conf = mddev->private;
1513         int err = -EEXIST;
1514         int mirror = 0;
1515         struct raid1_info *p;
1516         int first = 0;
1517         int last = conf->raid_disks - 1;
1518         struct request_queue *q = bdev_get_queue(rdev->bdev);
1519
1520         if (mddev->recovery_disabled == conf->recovery_disabled)
1521                 return -EBUSY;
1522
1523         if (rdev->raid_disk >= 0)
1524                 first = last = rdev->raid_disk;
1525
1526         if (q->merge_bvec_fn) {
1527                 set_bit(Unmerged, &rdev->flags);
1528                 mddev->merge_check_needed = 1;
1529         }
1530
1531         for (mirror = first; mirror <= last; mirror++) {
1532                 p = conf->mirrors+mirror;
1533                 if (!p->rdev) {
1534
1535                         disk_stack_limits(mddev->gendisk, rdev->bdev,
1536                                           rdev->data_offset << 9);
1537
1538                         p->head_position = 0;
1539                         rdev->raid_disk = mirror;
1540                         err = 0;
1541                         /* As all devices are equivalent, we don't need a full recovery
1542                          * if this was recently any drive of the array
1543                          */
1544                         if (rdev->saved_raid_disk < 0)
1545                                 conf->fullsync = 1;
1546                         rcu_assign_pointer(p->rdev, rdev);
1547                         break;
1548                 }
1549                 if (test_bit(WantReplacement, &p->rdev->flags) &&
1550                     p[conf->raid_disks].rdev == NULL) {
1551                         /* Add this device as a replacement */
1552                         clear_bit(In_sync, &rdev->flags);
1553                         set_bit(Replacement, &rdev->flags);
1554                         rdev->raid_disk = mirror;
1555                         err = 0;
1556                         conf->fullsync = 1;
1557                         rcu_assign_pointer(p[conf->raid_disks].rdev, rdev);
1558                         break;
1559                 }
1560         }
1561         if (err == 0 && test_bit(Unmerged, &rdev->flags)) {
1562                 /* Some requests might not have seen this new
1563                  * merge_bvec_fn.  We must wait for them to complete
1564                  * before merging the device fully.
1565                  * First we make sure any code which has tested
1566                  * our function has submitted the request, then
1567                  * we wait for all outstanding requests to complete.
1568                  */
1569                 synchronize_sched();
1570                 freeze_array(conf, 0);
1571                 unfreeze_array(conf);
1572                 clear_bit(Unmerged, &rdev->flags);
1573         }
1574         md_integrity_add_rdev(rdev, mddev);
1575         if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
1576                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
1577         print_conf(conf);
1578         return err;
1579 }
1580
1581 static int raid1_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
1582 {
1583         struct r1conf *conf = mddev->private;
1584         int err = 0;
1585         int number = rdev->raid_disk;
1586         struct raid1_info *p = conf->mirrors + number;
1587
1588         if (rdev != p->rdev)
1589                 p = conf->mirrors + conf->raid_disks + number;
1590
1591         print_conf(conf);
1592         if (rdev == p->rdev) {
1593                 if (test_bit(In_sync, &rdev->flags) ||
1594                     atomic_read(&rdev->nr_pending)) {
1595                         err = -EBUSY;
1596                         goto abort;
1597                 }
1598                 /* Only remove non-faulty devices if recovery
1599                  * is not possible.
1600                  */
1601                 if (!test_bit(Faulty, &rdev->flags) &&
1602                     mddev->recovery_disabled != conf->recovery_disabled &&
1603                     mddev->degraded < conf->raid_disks) {
1604                         err = -EBUSY;
1605                         goto abort;
1606                 }
1607                 p->rdev = NULL;
1608                 synchronize_rcu();
1609                 if (atomic_read(&rdev->nr_pending)) {
1610                         /* lost the race, try later */
1611                         err = -EBUSY;
1612                         p->rdev = rdev;
1613                         goto abort;
1614                 } else if (conf->mirrors[conf->raid_disks + number].rdev) {
1615                         /* We just removed a device that is being replaced.
1616                          * Move down the replacement.  We drain all IO before
1617                          * doing this to avoid confusion.
1618                          */
1619                         struct md_rdev *repl =
1620                                 conf->mirrors[conf->raid_disks + number].rdev;
1621                         freeze_array(conf, 0);
1622                         clear_bit(Replacement, &repl->flags);
1623                         p->rdev = repl;
1624                         conf->mirrors[conf->raid_disks + number].rdev = NULL;
1625                         unfreeze_array(conf);
1626                         clear_bit(WantReplacement, &rdev->flags);
1627                 } else
1628                         clear_bit(WantReplacement, &rdev->flags);
1629                 err = md_integrity_register(mddev);
1630         }
1631 abort:
1632
1633         print_conf(conf);
1634         return err;
1635 }
1636
1637
1638 static void end_sync_read(struct bio *bio, int error)
1639 {
1640         struct r1bio *r1_bio = bio->bi_private;
1641
1642         update_head_pos(r1_bio->read_disk, r1_bio);
1643
1644         /*
1645          * we have read a block, now it needs to be re-written,
1646          * or re-read if the read failed.
1647          * We don't do much here, just schedule handling by raid1d
1648          */
1649         if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1650                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1651
1652         if (atomic_dec_and_test(&r1_bio->remaining))
1653                 reschedule_retry(r1_bio);
1654 }
1655
1656 static void end_sync_write(struct bio *bio, int error)
1657 {
1658         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1659         struct r1bio *r1_bio = bio->bi_private;
1660         struct mddev *mddev = r1_bio->mddev;
1661         struct r1conf *conf = mddev->private;
1662         int mirror=0;
1663         sector_t first_bad;
1664         int bad_sectors;
1665
1666         mirror = find_bio_disk(r1_bio, bio);
1667
1668         if (!uptodate) {
1669                 sector_t sync_blocks = 0;
1670                 sector_t s = r1_bio->sector;
1671                 long sectors_to_go = r1_bio->sectors;
1672                 /* make sure these bits doesn't get cleared. */
1673                 do {
1674                         bitmap_end_sync(mddev->bitmap, s,
1675                                         &sync_blocks, 1);
1676                         s += sync_blocks;
1677                         sectors_to_go -= sync_blocks;
1678                 } while (sectors_to_go > 0);
1679                 set_bit(WriteErrorSeen,
1680                         &conf->mirrors[mirror].rdev->flags);
1681                 if (!test_and_set_bit(WantReplacement,
1682                                       &conf->mirrors[mirror].rdev->flags))
1683                         set_bit(MD_RECOVERY_NEEDED, &
1684                                 mddev->recovery);
1685                 set_bit(R1BIO_WriteError, &r1_bio->state);
1686         } else if (is_badblock(conf->mirrors[mirror].rdev,
1687                                r1_bio->sector,
1688                                r1_bio->sectors,
1689                                &first_bad, &bad_sectors) &&
1690                    !is_badblock(conf->mirrors[r1_bio->read_disk].rdev,
1691                                 r1_bio->sector,
1692                                 r1_bio->sectors,
1693                                 &first_bad, &bad_sectors)
1694                 )
1695                 set_bit(R1BIO_MadeGood, &r1_bio->state);
1696
1697         if (atomic_dec_and_test(&r1_bio->remaining)) {
1698                 int s = r1_bio->sectors;
1699                 if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
1700                     test_bit(R1BIO_WriteError, &r1_bio->state))
1701                         reschedule_retry(r1_bio);
1702                 else {
1703                         put_buf(r1_bio);
1704                         md_done_sync(mddev, s, uptodate);
1705                 }
1706         }
1707 }
1708
1709 static int r1_sync_page_io(struct md_rdev *rdev, sector_t sector,
1710                             int sectors, struct page *page, int rw)
1711 {
1712         if (sync_page_io(rdev, sector, sectors << 9, page, rw, false))
1713                 /* success */
1714                 return 1;
1715         if (rw == WRITE) {
1716                 set_bit(WriteErrorSeen, &rdev->flags);
1717                 if (!test_and_set_bit(WantReplacement,
1718                                       &rdev->flags))
1719                         set_bit(MD_RECOVERY_NEEDED, &
1720                                 rdev->mddev->recovery);
1721         }
1722         /* need to record an error - either for the block or the device */
1723         if (!rdev_set_badblocks(rdev, sector, sectors, 0))
1724                 md_error(rdev->mddev, rdev);
1725         return 0;
1726 }
1727
1728 static int fix_sync_read_error(struct r1bio *r1_bio)
1729 {
1730         /* Try some synchronous reads of other devices to get
1731          * good data, much like with normal read errors.  Only
1732          * read into the pages we already have so we don't
1733          * need to re-issue the read request.
1734          * We don't need to freeze the array, because being in an
1735          * active sync request, there is no normal IO, and
1736          * no overlapping syncs.
1737          * We don't need to check is_badblock() again as we
1738          * made sure that anything with a bad block in range
1739          * will have bi_end_io clear.
1740          */
1741         struct mddev *mddev = r1_bio->mddev;
1742         struct r1conf *conf = mddev->private;
1743         struct bio *bio = r1_bio->bios[r1_bio->read_disk];
1744         sector_t sect = r1_bio->sector;
1745         int sectors = r1_bio->sectors;
1746         int idx = 0;
1747
1748         while(sectors) {
1749                 int s = sectors;
1750                 int d = r1_bio->read_disk;
1751                 int success = 0;
1752                 struct md_rdev *rdev;
1753                 int start;
1754
1755                 if (s > (PAGE_SIZE>>9))
1756                         s = PAGE_SIZE >> 9;
1757                 do {
1758                         if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1759                                 /* No rcu protection needed here devices
1760                                  * can only be removed when no resync is
1761                                  * active, and resync is currently active
1762                                  */
1763                                 rdev = conf->mirrors[d].rdev;
1764                                 if (sync_page_io(rdev, sect, s<<9,
1765                                                  bio->bi_io_vec[idx].bv_page,
1766                                                  READ, false)) {
1767                                         success = 1;
1768                                         break;
1769                                 }
1770                         }
1771                         d++;
1772                         if (d == conf->raid_disks * 2)
1773                                 d = 0;
1774                 } while (!success && d != r1_bio->read_disk);
1775
1776                 if (!success) {
1777                         char b[BDEVNAME_SIZE];
1778                         int abort = 0;
1779                         /* Cannot read from anywhere, this block is lost.
1780                          * Record a bad block on each device.  If that doesn't
1781                          * work just disable and interrupt the recovery.
1782                          * Don't fail devices as that won't really help.
1783                          */
1784                         printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O read error"
1785                                " for block %llu\n",
1786                                mdname(mddev),
1787                                bdevname(bio->bi_bdev, b),
1788                                (unsigned long long)r1_bio->sector);
1789                         for (d = 0; d < conf->raid_disks * 2; d++) {
1790                                 rdev = conf->mirrors[d].rdev;
1791                                 if (!rdev || test_bit(Faulty, &rdev->flags))
1792                                         continue;
1793                                 if (!rdev_set_badblocks(rdev, sect, s, 0))
1794                                         abort = 1;
1795                         }
1796                         if (abort) {
1797                                 conf->recovery_disabled =
1798                                         mddev->recovery_disabled;
1799                                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1800                                 md_done_sync(mddev, r1_bio->sectors, 0);
1801                                 put_buf(r1_bio);
1802                                 return 0;
1803                         }
1804                         /* Try next page */
1805                         sectors -= s;
1806                         sect += s;
1807                         idx++;
1808                         continue;
1809                 }
1810
1811                 start = d;
1812                 /* write it back and re-read */
1813                 while (d != r1_bio->read_disk) {
1814                         if (d == 0)
1815                                 d = conf->raid_disks * 2;
1816                         d--;
1817                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1818                                 continue;
1819                         rdev = conf->mirrors[d].rdev;
1820                         if (r1_sync_page_io(rdev, sect, s,
1821                                             bio->bi_io_vec[idx].bv_page,
1822                                             WRITE) == 0) {
1823                                 r1_bio->bios[d]->bi_end_io = NULL;
1824                                 rdev_dec_pending(rdev, mddev);
1825                         }
1826                 }
1827                 d = start;
1828                 while (d != r1_bio->read_disk) {
1829                         if (d == 0)
1830                                 d = conf->raid_disks * 2;
1831                         d--;
1832                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1833                                 continue;
1834                         rdev = conf->mirrors[d].rdev;
1835                         if (r1_sync_page_io(rdev, sect, s,
1836                                             bio->bi_io_vec[idx].bv_page,
1837                                             READ) != 0)
1838                                 atomic_add(s, &rdev->corrected_errors);
1839                 }
1840                 sectors -= s;
1841                 sect += s;
1842                 idx ++;
1843         }
1844         set_bit(R1BIO_Uptodate, &r1_bio->state);
1845         set_bit(BIO_UPTODATE, &bio->bi_flags);
1846         return 1;
1847 }
1848
1849 static int process_checks(struct r1bio *r1_bio)
1850 {
1851         /* We have read all readable devices.  If we haven't
1852          * got the block, then there is no hope left.
1853          * If we have, then we want to do a comparison
1854          * and skip the write if everything is the same.
1855          * If any blocks failed to read, then we need to
1856          * attempt an over-write
1857          */
1858         struct mddev *mddev = r1_bio->mddev;
1859         struct r1conf *conf = mddev->private;
1860         int primary;
1861         int i;
1862         int vcnt;
1863
1864         /* Fix variable parts of all bios */
1865         vcnt = (r1_bio->sectors + PAGE_SIZE / 512 - 1) >> (PAGE_SHIFT - 9);
1866         for (i = 0; i < conf->raid_disks * 2; i++) {
1867                 int j;
1868                 int size;
1869                 int uptodate;
1870                 struct bio *b = r1_bio->bios[i];
1871                 if (b->bi_end_io != end_sync_read)
1872                         continue;
1873                 /* fixup the bio for reuse, but preserve BIO_UPTODATE */
1874                 uptodate = test_bit(BIO_UPTODATE, &b->bi_flags);
1875                 bio_reset(b);
1876                 if (!uptodate)
1877                         clear_bit(BIO_UPTODATE, &b->bi_flags);
1878                 b->bi_vcnt = vcnt;
1879                 b->bi_size = r1_bio->sectors << 9;
1880                 b->bi_sector = r1_bio->sector +
1881                         conf->mirrors[i].rdev->data_offset;
1882                 b->bi_bdev = conf->mirrors[i].rdev->bdev;
1883                 b->bi_end_io = end_sync_read;
1884                 b->bi_private = r1_bio;
1885
1886                 size = b->bi_size;
1887                 for (j = 0; j < vcnt ; j++) {
1888                         struct bio_vec *bi;
1889                         bi = &b->bi_io_vec[j];
1890                         bi->bv_offset = 0;
1891                         if (size > PAGE_SIZE)
1892                                 bi->bv_len = PAGE_SIZE;
1893                         else
1894                                 bi->bv_len = size;
1895                         size -= PAGE_SIZE;
1896                 }
1897         }
1898         for (primary = 0; primary < conf->raid_disks * 2; primary++)
1899                 if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1900                     test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
1901                         r1_bio->bios[primary]->bi_end_io = NULL;
1902                         rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1903                         break;
1904                 }
1905         r1_bio->read_disk = primary;
1906         for (i = 0; i < conf->raid_disks * 2; i++) {
1907                 int j;
1908                 struct bio *pbio = r1_bio->bios[primary];
1909                 struct bio *sbio = r1_bio->bios[i];
1910                 int uptodate = test_bit(BIO_UPTODATE, &sbio->bi_flags);
1911
1912                 if (sbio->bi_end_io != end_sync_read)
1913                         continue;
1914                 /* Now we can 'fixup' the BIO_UPTODATE flag */
1915                 set_bit(BIO_UPTODATE, &sbio->bi_flags);
1916
1917                 if (uptodate) {
1918                         for (j = vcnt; j-- ; ) {
1919                                 struct page *p, *s;
1920                                 p = pbio->bi_io_vec[j].bv_page;
1921                                 s = sbio->bi_io_vec[j].bv_page;
1922                                 if (memcmp(page_address(p),
1923                                            page_address(s),
1924                                            sbio->bi_io_vec[j].bv_len))
1925                                         break;
1926                         }
1927                 } else
1928                         j = 0;
1929                 if (j >= 0)
1930                         atomic64_add(r1_bio->sectors, &mddev->resync_mismatches);
1931                 if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
1932                               && uptodate)) {
1933                         /* No need to write to this device. */
1934                         sbio->bi_end_io = NULL;
1935                         rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1936                         continue;
1937                 }
1938
1939                 bio_copy_data(sbio, pbio);
1940         }
1941         return 0;
1942 }
1943
1944 static void sync_request_write(struct mddev *mddev, struct r1bio *r1_bio)
1945 {
1946         struct r1conf *conf = mddev->private;
1947         int i;
1948         int disks = conf->raid_disks * 2;
1949         struct bio *bio, *wbio;
1950
1951         bio = r1_bio->bios[r1_bio->read_disk];
1952
1953         if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
1954                 /* ouch - failed to read all of that. */
1955                 if (!fix_sync_read_error(r1_bio))
1956                         return;
1957
1958         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1959                 if (process_checks(r1_bio) < 0)
1960                         return;
1961         /*
1962          * schedule writes
1963          */
1964         atomic_set(&r1_bio->remaining, 1);
1965         for (i = 0; i < disks ; i++) {
1966                 wbio = r1_bio->bios[i];
1967                 if (wbio->bi_end_io == NULL ||
1968                     (wbio->bi_end_io == end_sync_read &&
1969                      (i == r1_bio->read_disk ||
1970                       !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
1971                         continue;
1972
1973                 wbio->bi_rw = WRITE;
1974                 wbio->bi_end_io = end_sync_write;
1975                 atomic_inc(&r1_bio->remaining);
1976                 md_sync_acct(conf->mirrors[i].rdev->bdev, bio_sectors(wbio));
1977
1978                 generic_make_request(wbio);
1979         }
1980
1981         if (atomic_dec_and_test(&r1_bio->remaining)) {
1982                 /* if we're here, all write(s) have completed, so clean up */
1983                 int s = r1_bio->sectors;
1984                 if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
1985                     test_bit(R1BIO_WriteError, &r1_bio->state))
1986                         reschedule_retry(r1_bio);
1987                 else {
1988                         put_buf(r1_bio);
1989                         md_done_sync(mddev, s, 1);
1990                 }
1991         }
1992 }
1993
1994 /*
1995  * This is a kernel thread which:
1996  *
1997  *      1.      Retries failed read operations on working mirrors.
1998  *      2.      Updates the raid superblock when problems encounter.
1999  *      3.      Performs writes following reads for array synchronising.
2000  */
2001
2002 static void fix_read_error(struct r1conf *conf, int read_disk,
2003                            sector_t sect, int sectors)
2004 {
2005         struct mddev *mddev = conf->mddev;
2006         while(sectors) {
2007                 int s = sectors;
2008                 int d = read_disk;
2009                 int success = 0;
2010                 int start;
2011                 struct md_rdev *rdev;
2012
2013                 if (s > (PAGE_SIZE>>9))
2014                         s = PAGE_SIZE >> 9;
2015
2016                 do {
2017                         /* Note: no rcu protection needed here
2018                          * as this is synchronous in the raid1d thread
2019                          * which is the thread that might remove
2020                          * a device.  If raid1d ever becomes multi-threaded....
2021                          */
2022                         sector_t first_bad;
2023                         int bad_sectors;
2024
2025                         rdev = conf->mirrors[d].rdev;
2026                         if (rdev &&
2027                             (test_bit(In_sync, &rdev->flags) ||
2028                              (!test_bit(Faulty, &rdev->flags) &&
2029                               rdev->recovery_offset >= sect + s)) &&
2030                             is_badblock(rdev, sect, s,
2031                                         &first_bad, &bad_sectors) == 0 &&
2032                             sync_page_io(rdev, sect, s<<9,
2033                                          conf->tmppage, READ, false))
2034                                 success = 1;
2035                         else {
2036                                 d++;
2037                                 if (d == conf->raid_disks * 2)
2038                                         d = 0;
2039                         }
2040                 } while (!success && d != read_disk);
2041
2042                 if (!success) {
2043                         /* Cannot read from anywhere - mark it bad */
2044                         struct md_rdev *rdev = conf->mirrors[read_disk].rdev;
2045                         if (!rdev_set_badblocks(rdev, sect, s, 0))
2046                                 md_error(mddev, rdev);
2047                         break;
2048                 }
2049                 /* write it back and re-read */
2050                 start = d;
2051                 while (d != read_disk) {
2052                         if (d==0)
2053                                 d = conf->raid_disks * 2;
2054                         d--;
2055                         rdev = conf->mirrors[d].rdev;
2056                         if (rdev &&
2057                             !test_bit(Faulty, &rdev->flags))
2058                                 r1_sync_page_io(rdev, sect, s,
2059                                                 conf->tmppage, WRITE);
2060                 }
2061                 d = start;
2062                 while (d != read_disk) {
2063                         char b[BDEVNAME_SIZE];
2064                         if (d==0)
2065                                 d = conf->raid_disks * 2;
2066                         d--;
2067                         rdev = conf->mirrors[d].rdev;
2068                         if (rdev &&
2069                             !test_bit(Faulty, &rdev->flags)) {
2070                                 if (r1_sync_page_io(rdev, sect, s,
2071                                                     conf->tmppage, READ)) {
2072                                         atomic_add(s, &rdev->corrected_errors);
2073                                         printk(KERN_INFO
2074                                                "md/raid1:%s: read error corrected "
2075                                                "(%d sectors at %llu on %s)\n",
2076                                                mdname(mddev), s,
2077                                                (unsigned long long)(sect +
2078                                                    rdev->data_offset),
2079                                                bdevname(rdev->bdev, b));
2080                                 }
2081                         }
2082                 }
2083                 sectors -= s;
2084                 sect += s;
2085         }
2086 }
2087
2088 static int narrow_write_error(struct r1bio *r1_bio, int i)
2089 {
2090         struct mddev *mddev = r1_bio->mddev;
2091         struct r1conf *conf = mddev->private;
2092         struct md_rdev *rdev = conf->mirrors[i].rdev;
2093
2094         /* bio has the data to be written to device 'i' where
2095          * we just recently had a write error.
2096          * We repeatedly clone the bio and trim down to one block,
2097          * then try the write.  Where the write fails we record
2098          * a bad block.
2099          * It is conceivable that the bio doesn't exactly align with
2100          * blocks.  We must handle this somehow.
2101          *
2102          * We currently own a reference on the rdev.
2103          */
2104
2105         int block_sectors;
2106         sector_t sector;
2107         int sectors;
2108         int sect_to_write = r1_bio->sectors;
2109         int ok = 1;
2110
2111         if (rdev->badblocks.shift < 0)
2112                 return 0;
2113
2114         block_sectors = 1 << rdev->badblocks.shift;
2115         sector = r1_bio->sector;
2116         sectors = ((sector + block_sectors)
2117                    & ~(sector_t)(block_sectors - 1))
2118                 - sector;
2119
2120         while (sect_to_write) {
2121                 struct bio *wbio;
2122                 if (sectors > sect_to_write)
2123                         sectors = sect_to_write;
2124                 /* Write at 'sector' for 'sectors'*/
2125
2126                 if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
2127                         unsigned vcnt = r1_bio->behind_page_count;
2128                         struct bio_vec *vec = r1_bio->behind_bvecs;
2129
2130                         while (!vec->bv_page) {
2131                                 vec++;
2132                                 vcnt--;
2133                         }
2134
2135                         wbio = bio_alloc_mddev(GFP_NOIO, vcnt, mddev);
2136                         memcpy(wbio->bi_io_vec, vec, vcnt * sizeof(struct bio_vec));
2137
2138                         wbio->bi_vcnt = vcnt;
2139                 } else {
2140                         wbio = bio_clone_mddev(r1_bio->master_bio, GFP_NOIO, mddev);
2141                 }
2142
2143                 wbio->bi_rw = WRITE;
2144                 wbio->bi_sector = r1_bio->sector;
2145                 wbio->bi_size = r1_bio->sectors << 9;
2146
2147                 md_trim_bio(wbio, sector - r1_bio->sector, sectors);
2148                 wbio->bi_sector += rdev->data_offset;
2149                 wbio->bi_bdev = rdev->bdev;
2150                 if (submit_bio_wait(WRITE, wbio) == 0)
2151                         /* failure! */
2152                         ok = rdev_set_badblocks(rdev, sector,
2153                                                 sectors, 0)
2154                                 && ok;
2155
2156                 bio_put(wbio);
2157                 sect_to_write -= sectors;
2158                 sector += sectors;
2159                 sectors = block_sectors;
2160         }
2161         return ok;
2162 }
2163
2164 static void handle_sync_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2165 {
2166         int m;
2167         int s = r1_bio->sectors;
2168         for (m = 0; m < conf->raid_disks * 2 ; m++) {
2169                 struct md_rdev *rdev = conf->mirrors[m].rdev;
2170                 struct bio *bio = r1_bio->bios[m];
2171                 if (bio->bi_end_io == NULL)
2172                         continue;
2173                 if (test_bit(BIO_UPTODATE, &bio->bi_flags) &&
2174                     test_bit(R1BIO_MadeGood, &r1_bio->state)) {
2175                         rdev_clear_badblocks(rdev, r1_bio->sector, s, 0);
2176                 }
2177                 if (!test_bit(BIO_UPTODATE, &bio->bi_flags) &&
2178                     test_bit(R1BIO_WriteError, &r1_bio->state)) {
2179                         if (!rdev_set_badblocks(rdev, r1_bio->sector, s, 0))
2180                                 md_error(conf->mddev, rdev);
2181                 }
2182         }
2183         put_buf(r1_bio);
2184         md_done_sync(conf->mddev, s, 1);
2185 }
2186
2187 static void handle_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2188 {
2189         int m;
2190         for (m = 0; m < conf->raid_disks * 2 ; m++)
2191                 if (r1_bio->bios[m] == IO_MADE_GOOD) {
2192                         struct md_rdev *rdev = conf->mirrors[m].rdev;
2193                         rdev_clear_badblocks(rdev,
2194                                              r1_bio->sector,
2195                                              r1_bio->sectors, 0);
2196                         rdev_dec_pending(rdev, conf->mddev);
2197                 } else if (r1_bio->bios[m] != NULL) {
2198                         /* This drive got a write error.  We need to
2199                          * narrow down and record precise write
2200                          * errors.
2201                          */
2202                         if (!narrow_write_error(r1_bio, m)) {
2203                                 md_error(conf->mddev,
2204                                          conf->mirrors[m].rdev);
2205                                 /* an I/O failed, we can't clear the bitmap */
2206                                 set_bit(R1BIO_Degraded, &r1_bio->state);
2207                         }
2208                         rdev_dec_pending(conf->mirrors[m].rdev,
2209                                          conf->mddev);
2210                 }
2211         if (test_bit(R1BIO_WriteError, &r1_bio->state))
2212                 close_write(r1_bio);
2213         raid_end_bio_io(r1_bio);
2214 }
2215
2216 static void handle_read_error(struct r1conf *conf, struct r1bio *r1_bio)
2217 {
2218         int disk;
2219         int max_sectors;
2220         struct mddev *mddev = conf->mddev;
2221         struct bio *bio;
2222         char b[BDEVNAME_SIZE];
2223         struct md_rdev *rdev;
2224
2225         clear_bit(R1BIO_ReadError, &r1_bio->state);
2226         /* we got a read error. Maybe the drive is bad.  Maybe just
2227          * the block and we can fix it.
2228          * We freeze all other IO, and try reading the block from
2229          * other devices.  When we find one, we re-write
2230          * and check it that fixes the read error.
2231          * This is all done synchronously while the array is
2232          * frozen
2233          */
2234         if (mddev->ro == 0) {
2235                 freeze_array(conf, 1);
2236                 fix_read_error(conf, r1_bio->read_disk,
2237                                r1_bio->sector, r1_bio->sectors);
2238                 unfreeze_array(conf);
2239         } else
2240                 md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
2241         rdev_dec_pending(conf->mirrors[r1_bio->read_disk].rdev, conf->mddev);
2242
2243         bio = r1_bio->bios[r1_bio->read_disk];
2244         bdevname(bio->bi_bdev, b);
2245 read_more:
2246         disk = read_balance(conf, r1_bio, &max_sectors);
2247         if (disk == -1) {
2248                 printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O"
2249                        " read error for block %llu\n",
2250                        mdname(mddev), b, (unsigned long long)r1_bio->sector);
2251                 raid_end_bio_io(r1_bio);
2252         } else {
2253                 const unsigned long do_sync
2254                         = r1_bio->master_bio->bi_rw & REQ_SYNC;
2255                 if (bio) {
2256                         r1_bio->bios[r1_bio->read_disk] =
2257                                 mddev->ro ? IO_BLOCKED : NULL;
2258                         bio_put(bio);
2259                 }
2260                 r1_bio->read_disk = disk;
2261                 bio = bio_clone_mddev(r1_bio->master_bio, GFP_NOIO, mddev);
2262                 md_trim_bio(bio, r1_bio->sector - bio->bi_sector, max_sectors);
2263                 r1_bio->bios[r1_bio->read_disk] = bio;
2264                 rdev = conf->mirrors[disk].rdev;
2265                 printk_ratelimited(KERN_ERR
2266                                    "md/raid1:%s: redirecting sector %llu"
2267                                    " to other mirror: %s\n",
2268                                    mdname(mddev),
2269                                    (unsigned long long)r1_bio->sector,
2270                                    bdevname(rdev->bdev, b));
2271                 bio->bi_sector = r1_bio->sector + rdev->data_offset;
2272                 bio->bi_bdev = rdev->bdev;
2273                 bio->bi_end_io = raid1_end_read_request;
2274                 bio->bi_rw = READ | do_sync;
2275                 bio->bi_private = r1_bio;
2276                 if (max_sectors < r1_bio->sectors) {
2277                         /* Drat - have to split this up more */
2278                         struct bio *mbio = r1_bio->master_bio;
2279                         int sectors_handled = (r1_bio->sector + max_sectors
2280                                                - mbio->bi_sector);
2281                         r1_bio->sectors = max_sectors;
2282                         spin_lock_irq(&conf->device_lock);
2283                         if (mbio->bi_phys_segments == 0)
2284                                 mbio->bi_phys_segments = 2;
2285                         else
2286                                 mbio->bi_phys_segments++;
2287                         spin_unlock_irq(&conf->device_lock);
2288                         generic_make_request(bio);
2289                         bio = NULL;
2290
2291                         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
2292
2293                         r1_bio->master_bio = mbio;
2294                         r1_bio->sectors = bio_sectors(mbio) - sectors_handled;
2295                         r1_bio->state = 0;
2296                         set_bit(R1BIO_ReadError, &r1_bio->state);
2297                         r1_bio->mddev = mddev;
2298                         r1_bio->sector = mbio->bi_sector + sectors_handled;
2299
2300                         goto read_more;
2301                 } else
2302                         generic_make_request(bio);
2303         }
2304 }
2305
2306 static void raid1d(struct md_thread *thread)
2307 {
2308         struct mddev *mddev = thread->mddev;
2309         struct r1bio *r1_bio;
2310         unsigned long flags;
2311         struct r1conf *conf = mddev->private;
2312         struct list_head *head = &conf->retry_list;
2313         struct blk_plug plug;
2314
2315         md_check_recovery(mddev);
2316
2317         blk_start_plug(&plug);
2318         for (;;) {
2319
2320                 flush_pending_writes(conf);
2321
2322                 spin_lock_irqsave(&conf->device_lock, flags);
2323                 if (list_empty(head)) {
2324                         spin_unlock_irqrestore(&conf->device_lock, flags);
2325                         break;
2326                 }
2327                 r1_bio = list_entry(head->prev, struct r1bio, retry_list);
2328                 list_del(head->prev);
2329                 conf->nr_queued--;
2330                 spin_unlock_irqrestore(&conf->device_lock, flags);
2331
2332                 mddev = r1_bio->mddev;
2333                 conf = mddev->private;
2334                 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
2335                         if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2336                             test_bit(R1BIO_WriteError, &r1_bio->state))
2337                                 handle_sync_write_finished(conf, r1_bio);
2338                         else
2339                                 sync_request_write(mddev, r1_bio);
2340                 } else if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2341                            test_bit(R1BIO_WriteError, &r1_bio->state))
2342                         handle_write_finished(conf, r1_bio);
2343                 else if (test_bit(R1BIO_ReadError, &r1_bio->state))
2344                         handle_read_error(conf, r1_bio);
2345                 else
2346                         /* just a partial read to be scheduled from separate
2347                          * context
2348                          */
2349                         generic_make_request(r1_bio->bios[r1_bio->read_disk]);
2350
2351                 cond_resched();
2352                 if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
2353                         md_check_recovery(mddev);
2354         }
2355         blk_finish_plug(&plug);
2356 }
2357
2358
2359 static int init_resync(struct r1conf *conf)
2360 {
2361         int buffs;
2362
2363         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
2364         BUG_ON(conf->r1buf_pool);
2365         conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
2366                                           conf->poolinfo);
2367         if (!conf->r1buf_pool)
2368                 return -ENOMEM;
2369         conf->next_resync = 0;
2370         return 0;
2371 }
2372
2373 /*
2374  * perform a "sync" on one "block"
2375  *
2376  * We need to make sure that no normal I/O request - particularly write
2377  * requests - conflict with active sync requests.
2378  *
2379  * This is achieved by tracking pending requests and a 'barrier' concept
2380  * that can be installed to exclude normal IO requests.
2381  */
2382
2383 static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster)
2384 {
2385         struct r1conf *conf = mddev->private;
2386         struct r1bio *r1_bio;
2387         struct bio *bio;
2388         sector_t max_sector, nr_sectors;
2389         int disk = -1;
2390         int i;
2391         int wonly = -1;
2392         int write_targets = 0, read_targets = 0;
2393         sector_t sync_blocks;
2394         int still_degraded = 0;
2395         int good_sectors = RESYNC_SECTORS;
2396         int min_bad = 0; /* number of sectors that are bad in all devices */
2397
2398         if (!conf->r1buf_pool)
2399                 if (init_resync(conf))
2400                         return 0;
2401
2402         max_sector = mddev->dev_sectors;
2403         if (sector_nr >= max_sector) {
2404                 /* If we aborted, we need to abort the
2405                  * sync on the 'current' bitmap chunk (there will
2406                  * only be one in raid1 resync.
2407                  * We can find the current addess in mddev->curr_resync
2408                  */
2409                 if (mddev->curr_resync < max_sector) /* aborted */
2410                         bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
2411                                                 &sync_blocks, 1);
2412                 else /* completed sync */
2413                         conf->fullsync = 0;
2414
2415                 bitmap_close_sync(mddev->bitmap);
2416                 close_sync(conf);
2417                 return 0;
2418         }
2419
2420         if (mddev->bitmap == NULL &&
2421             mddev->recovery_cp == MaxSector &&
2422             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
2423             conf->fullsync == 0) {
2424                 *skipped = 1;
2425                 return max_sector - sector_nr;
2426         }
2427         /* before building a request, check if we can skip these blocks..
2428          * This call the bitmap_start_sync doesn't actually record anything
2429          */
2430         if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
2431             !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2432                 /* We can skip this block, and probably several more */
2433                 *skipped = 1;
2434                 return sync_blocks;
2435         }
2436         /*
2437          * If there is non-resync activity waiting for a turn,
2438          * and resync is going fast enough,
2439          * then let it though before starting on this new sync request.
2440          */
2441         if (!go_faster && conf->nr_waiting)
2442                 msleep_interruptible(1000);
2443
2444         bitmap_cond_end_sync(mddev->bitmap, sector_nr);
2445         r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
2446         raise_barrier(conf);
2447
2448         conf->next_resync = sector_nr;
2449
2450         rcu_read_lock();
2451         /*
2452          * If we get a correctably read error during resync or recovery,
2453          * we might want to read from a different device.  So we
2454          * flag all drives that could conceivably be read from for READ,
2455          * and any others (which will be non-In_sync devices) for WRITE.
2456          * If a read fails, we try reading from something else for which READ
2457          * is OK.
2458          */
2459
2460         r1_bio->mddev = mddev;
2461         r1_bio->sector = sector_nr;
2462         r1_bio->state = 0;
2463         set_bit(R1BIO_IsSync, &r1_bio->state);
2464
2465         for (i = 0; i < conf->raid_disks * 2; i++) {
2466                 struct md_rdev *rdev;
2467                 bio = r1_bio->bios[i];
2468                 bio_reset(bio);
2469
2470                 rdev = rcu_dereference(conf->mirrors[i].rdev);
2471                 if (rdev == NULL ||
2472                     test_bit(Faulty, &rdev->flags)) {
2473                         if (i < conf->raid_disks)
2474                                 still_degraded = 1;
2475                 } else if (!test_bit(In_sync, &rdev->flags)) {
2476                         bio->bi_rw = WRITE;
2477                         bio->bi_end_io = end_sync_write;
2478                         write_targets ++;
2479                 } else {
2480                         /* may need to read from here */
2481                         sector_t first_bad = MaxSector;
2482                         int bad_sectors;
2483
2484                         if (is_badblock(rdev, sector_nr, good_sectors,
2485                                         &first_bad, &bad_sectors)) {
2486                                 if (first_bad > sector_nr)
2487                                         good_sectors = first_bad - sector_nr;
2488                                 else {
2489                                         bad_sectors -= (sector_nr - first_bad);
2490                                         if (min_bad == 0 ||
2491                                             min_bad > bad_sectors)
2492                                                 min_bad = bad_sectors;
2493                                 }
2494                         }
2495                         if (sector_nr < first_bad) {
2496                                 if (test_bit(WriteMostly, &rdev->flags)) {
2497                                         if (wonly < 0)
2498                                                 wonly = i;
2499                                 } else {
2500                                         if (disk < 0)
2501                                                 disk = i;
2502                                 }
2503                                 bio->bi_rw = READ;
2504                                 bio->bi_end_io = end_sync_read;
2505                                 read_targets++;
2506                         } else if (!test_bit(WriteErrorSeen, &rdev->flags) &&
2507                                 test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
2508                                 !test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) {
2509                                 /*
2510                                  * The device is suitable for reading (InSync),
2511                                  * but has bad block(s) here. Let's try to correct them,
2512                                  * if we are doing resync or repair. Otherwise, leave
2513                                  * this device alone for this sync request.
2514                                  */
2515                                 bio->bi_rw = WRITE;
2516                                 bio->bi_end_io = end_sync_write;
2517                                 write_targets++;
2518                         }
2519                 }
2520                 if (bio->bi_end_io) {
2521                         atomic_inc(&rdev->nr_pending);
2522                         bio->bi_sector = sector_nr + rdev->data_offset;
2523                         bio->bi_bdev = rdev->bdev;
2524                         bio->bi_private = r1_bio;
2525                 }
2526         }
2527         rcu_read_unlock();
2528         if (disk < 0)
2529                 disk = wonly;
2530         r1_bio->read_disk = disk;
2531
2532         if (read_targets == 0 && min_bad > 0) {
2533                 /* These sectors are bad on all InSync devices, so we
2534                  * need to mark them bad on all write targets
2535                  */
2536                 int ok = 1;
2537                 for (i = 0 ; i < conf->raid_disks * 2 ; i++)
2538                         if (r1_bio->bios[i]->bi_end_io == end_sync_write) {
2539                                 struct md_rdev *rdev = conf->mirrors[i].rdev;
2540                                 ok = rdev_set_badblocks(rdev, sector_nr,
2541                                                         min_bad, 0
2542                                         ) && ok;
2543                         }
2544                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
2545                 *skipped = 1;
2546                 put_buf(r1_bio);
2547
2548                 if (!ok) {
2549                         /* Cannot record the badblocks, so need to
2550                          * abort the resync.
2551                          * If there are multiple read targets, could just
2552                          * fail the really bad ones ???
2553                          */
2554                         conf->recovery_disabled = mddev->recovery_disabled;
2555                         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2556                         return 0;
2557                 } else
2558                         return min_bad;
2559
2560         }
2561         if (min_bad > 0 && min_bad < good_sectors) {
2562                 /* only resync enough to reach the next bad->good
2563                  * transition */
2564                 good_sectors = min_bad;
2565         }
2566
2567         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
2568                 /* extra read targets are also write targets */
2569                 write_targets += read_targets-1;
2570
2571         if (write_targets == 0 || read_targets == 0) {
2572                 /* There is nowhere to write, so all non-sync
2573                  * drives must be failed - so we are finished
2574                  */
2575                 sector_t rv;
2576                 if (min_bad > 0)
2577                         max_sector = sector_nr + min_bad;
2578                 rv = max_sector - sector_nr;
2579                 *skipped = 1;
2580                 put_buf(r1_bio);
2581                 return rv;
2582         }
2583
2584         if (max_sector > mddev->resync_max)
2585                 max_sector = mddev->resync_max; /* Don't do IO beyond here */
2586         if (max_sector > sector_nr + good_sectors)
2587                 max_sector = sector_nr + good_sectors;
2588         nr_sectors = 0;
2589         sync_blocks = 0;
2590         do {
2591                 struct page *page;
2592                 int len = PAGE_SIZE;
2593                 if (sector_nr + (len>>9) > max_sector)
2594                         len = (max_sector - sector_nr) << 9;
2595                 if (len == 0)
2596                         break;
2597                 if (sync_blocks == 0) {
2598                         if (!bitmap_start_sync(mddev->bitmap, sector_nr,
2599                                                &sync_blocks, still_degraded) &&
2600                             !conf->fullsync &&
2601                             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2602                                 break;
2603                         BUG_ON(sync_blocks < (PAGE_SIZE>>9));
2604                         if ((len >> 9) > sync_blocks)
2605                                 len = sync_blocks<<9;
2606                 }
2607
2608                 for (i = 0 ; i < conf->raid_disks * 2; i++) {
2609                         bio = r1_bio->bios[i];
2610                         if (bio->bi_end_io) {
2611                                 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
2612                                 if (bio_add_page(bio, page, len, 0) == 0) {
2613                                         /* stop here */
2614                                         bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
2615                                         while (i > 0) {
2616                                                 i--;
2617                                                 bio = r1_bio->bios[i];
2618                                                 if (bio->bi_end_io==NULL)
2619                                                         continue;
2620                                                 /* remove last page from this bio */
2621                                                 bio->bi_vcnt--;
2622                                                 bio->bi_size -= len;
2623                                                 bio->bi_flags &= ~(1<< BIO_SEG_VALID);
2624                                         }
2625                                         goto bio_full;
2626                                 }
2627                         }
2628                 }
2629                 nr_sectors += len>>9;
2630                 sector_nr += len>>9;
2631                 sync_blocks -= (len>>9);
2632         } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
2633  bio_full:
2634         r1_bio->sectors = nr_sectors;
2635
2636         /* For a user-requested sync, we read all readable devices and do a
2637          * compare
2638          */
2639         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2640                 atomic_set(&r1_bio->remaining, read_targets);
2641                 for (i = 0; i < conf->raid_disks * 2 && read_targets; i++) {
2642                         bio = r1_bio->bios[i];
2643                         if (bio->bi_end_io == end_sync_read) {
2644                                 read_targets--;
2645                                 md_sync_acct(bio->bi_bdev, nr_sectors);
2646                                 generic_make_request(bio);
2647                         }
2648                 }
2649         } else {
2650                 atomic_set(&r1_bio->remaining, 1);
2651                 bio = r1_bio->bios[r1_bio->read_disk];
2652                 md_sync_acct(bio->bi_bdev, nr_sectors);
2653                 generic_make_request(bio);
2654
2655         }
2656         return nr_sectors;
2657 }
2658
2659 static sector_t raid1_size(struct mddev *mddev, sector_t sectors, int raid_disks)
2660 {
2661         if (sectors)
2662                 return sectors;
2663
2664         return mddev->dev_sectors;
2665 }
2666
2667 static struct r1conf *setup_conf(struct mddev *mddev)
2668 {
2669         struct r1conf *conf;
2670         int i;
2671         struct raid1_info *disk;
2672         struct md_rdev *rdev;
2673         int err = -ENOMEM;
2674
2675         conf = kzalloc(sizeof(struct r1conf), GFP_KERNEL);
2676         if (!conf)
2677                 goto abort;
2678
2679         conf->mirrors = kzalloc(sizeof(struct raid1_info)
2680                                 * mddev->raid_disks * 2,
2681                                  GFP_KERNEL);
2682         if (!conf->mirrors)
2683                 goto abort;
2684
2685         conf->tmppage = alloc_page(GFP_KERNEL);
2686         if (!conf->tmppage)
2687                 goto abort;
2688
2689         conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
2690         if (!conf->poolinfo)
2691                 goto abort;
2692         conf->poolinfo->raid_disks = mddev->raid_disks * 2;
2693         conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2694                                           r1bio_pool_free,
2695                                           conf->poolinfo);
2696         if (!conf->r1bio_pool)
2697                 goto abort;
2698
2699         conf->poolinfo->mddev = mddev;
2700
2701         err = -EINVAL;
2702         spin_lock_init(&conf->device_lock);
2703         rdev_for_each(rdev, mddev) {
2704                 struct request_queue *q;
2705                 int disk_idx = rdev->raid_disk;
2706                 if (disk_idx >= mddev->raid_disks
2707                     || disk_idx < 0)
2708                         continue;
2709                 if (test_bit(Replacement, &rdev->flags))
2710                         disk = conf->mirrors + mddev->raid_disks + disk_idx;
2711                 else
2712                         disk = conf->mirrors + disk_idx;
2713
2714                 if (disk->rdev)
2715                         goto abort;
2716                 disk->rdev = rdev;
2717                 q = bdev_get_queue(rdev->bdev);
2718                 if (q->merge_bvec_fn)
2719                         mddev->merge_check_needed = 1;
2720
2721                 disk->head_position = 0;
2722                 disk->seq_start = MaxSector;
2723         }
2724         conf->raid_disks = mddev->raid_disks;
2725         conf->mddev = mddev;
2726         INIT_LIST_HEAD(&conf->retry_list);
2727
2728         spin_lock_init(&conf->resync_lock);
2729         init_waitqueue_head(&conf->wait_barrier);
2730
2731         bio_list_init(&conf->pending_bio_list);
2732         conf->pending_count = 0;
2733         conf->recovery_disabled = mddev->recovery_disabled - 1;
2734
2735         err = -EIO;
2736         for (i = 0; i < conf->raid_disks * 2; i++) {
2737
2738                 disk = conf->mirrors + i;
2739
2740                 if (i < conf->raid_disks &&
2741                     disk[conf->raid_disks].rdev) {
2742                         /* This slot has a replacement. */
2743                         if (!disk->rdev) {
2744                                 /* No original, just make the replacement
2745                                  * a recovering spare
2746                                  */
2747                                 disk->rdev =
2748                                         disk[conf->raid_disks].rdev;
2749                                 disk[conf->raid_disks].rdev = NULL;
2750                         } else if (!test_bit(In_sync, &disk->rdev->flags))
2751                                 /* Original is not in_sync - bad */
2752                                 goto abort;
2753                 }
2754
2755                 if (!disk->rdev ||
2756                     !test_bit(In_sync, &disk->rdev->flags)) {
2757                         disk->head_position = 0;
2758                         if (disk->rdev &&
2759                             (disk->rdev->saved_raid_disk < 0))
2760                                 conf->fullsync = 1;
2761                 }
2762         }
2763
2764         err = -ENOMEM;
2765         conf->thread = md_register_thread(raid1d, mddev, "raid1");
2766         if (!conf->thread) {
2767                 printk(KERN_ERR
2768                        "md/raid1:%s: couldn't allocate thread\n",
2769                        mdname(mddev));
2770                 goto abort;
2771         }
2772
2773         return conf;
2774
2775  abort:
2776         if (conf) {
2777                 if (conf->r1bio_pool)
2778                         mempool_destroy(conf->r1bio_pool);
2779                 kfree(conf->mirrors);
2780                 safe_put_page(conf->tmppage);
2781                 kfree(conf->poolinfo);
2782                 kfree(conf);
2783         }
2784         return ERR_PTR(err);
2785 }
2786
2787 static int stop(struct mddev *mddev);
2788 static int run(struct mddev *mddev)
2789 {
2790         struct r1conf *conf;
2791         int i;
2792         struct md_rdev *rdev;
2793         int ret;
2794         bool discard_supported = false;
2795
2796         if (mddev->level != 1) {
2797                 printk(KERN_ERR "md/raid1:%s: raid level not set to mirroring (%d)\n",
2798                        mdname(mddev), mddev->level);
2799                 return -EIO;
2800         }
2801         if (mddev->reshape_position != MaxSector) {
2802                 printk(KERN_ERR "md/raid1:%s: reshape_position set but not supported\n",
2803                        mdname(mddev));
2804                 return -EIO;
2805         }
2806         /*
2807          * copy the already verified devices into our private RAID1
2808          * bookkeeping area. [whatever we allocate in run(),
2809          * should be freed in stop()]
2810          */
2811         if (mddev->private == NULL)
2812                 conf = setup_conf(mddev);
2813         else
2814                 conf = mddev->private;
2815
2816         if (IS_ERR(conf))
2817                 return PTR_ERR(conf);
2818
2819         if (mddev->queue)
2820                 blk_queue_max_write_same_sectors(mddev->queue, 0);
2821
2822         rdev_for_each(rdev, mddev) {
2823                 if (!mddev->gendisk)
2824                         continue;
2825                 disk_stack_limits(mddev->gendisk, rdev->bdev,
2826                                   rdev->data_offset << 9);
2827                 if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
2828                         discard_supported = true;
2829         }
2830
2831         mddev->degraded = 0;
2832         for (i=0; i < conf->raid_disks; i++)
2833                 if (conf->mirrors[i].rdev == NULL ||
2834                     !test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
2835                     test_bit(Faulty, &conf->mirrors[i].rdev->flags))
2836                         mddev->degraded++;
2837
2838         if (conf->raid_disks - mddev->degraded == 1)
2839                 mddev->recovery_cp = MaxSector;
2840
2841         if (mddev->recovery_cp != MaxSector)
2842                 printk(KERN_NOTICE "md/raid1:%s: not clean"
2843                        " -- starting background reconstruction\n",
2844                        mdname(mddev));
2845         printk(KERN_INFO
2846                 "md/raid1:%s: active with %d out of %d mirrors\n",
2847                 mdname(mddev), mddev->raid_disks - mddev->degraded,
2848                 mddev->raid_disks);
2849
2850         /*
2851          * Ok, everything is just fine now
2852          */
2853         mddev->thread = conf->thread;
2854         conf->thread = NULL;
2855         mddev->private = conf;
2856
2857         md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
2858
2859         if (mddev->queue) {
2860                 mddev->queue->backing_dev_info.congested_fn = raid1_congested;
2861                 mddev->queue->backing_dev_info.congested_data = mddev;
2862                 blk_queue_merge_bvec(mddev->queue, raid1_mergeable_bvec);
2863
2864                 if (discard_supported)
2865                         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
2866                                                 mddev->queue);
2867                 else
2868                         queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
2869                                                   mddev->queue);
2870         }
2871
2872         ret =  md_integrity_register(mddev);
2873         if (ret)
2874                 stop(mddev);
2875         return ret;
2876 }
2877
2878 static int stop(struct mddev *mddev)
2879 {
2880         struct r1conf *conf = mddev->private;
2881         struct bitmap *bitmap = mddev->bitmap;
2882
2883         /* wait for behind writes to complete */
2884         if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
2885                 printk(KERN_INFO "md/raid1:%s: behind writes in progress - waiting to stop.\n",
2886                        mdname(mddev));
2887                 /* need to kick something here to make sure I/O goes? */
2888                 wait_event(bitmap->behind_wait,
2889                            atomic_read(&bitmap->behind_writes) == 0);
2890         }
2891
2892         raise_barrier(conf);
2893         lower_barrier(conf);
2894
2895         md_unregister_thread(&mddev->thread);
2896         if (conf->r1bio_pool)
2897                 mempool_destroy(conf->r1bio_pool);
2898         kfree(conf->mirrors);
2899         safe_put_page(conf->tmppage);
2900         kfree(conf->poolinfo);
2901         kfree(conf);
2902         mddev->private = NULL;
2903         return 0;
2904 }
2905
2906 static int raid1_resize(struct mddev *mddev, sector_t sectors)
2907 {
2908         /* no resync is happening, and there is enough space
2909          * on all devices, so we can resize.
2910          * We need to make sure resync covers any new space.
2911          * If the array is shrinking we should possibly wait until
2912          * any io in the removed space completes, but it hardly seems
2913          * worth it.
2914          */
2915         sector_t newsize = raid1_size(mddev, sectors, 0);
2916         if (mddev->external_size &&
2917             mddev->array_sectors > newsize)
2918                 return -EINVAL;
2919         if (mddev->bitmap) {
2920                 int ret = bitmap_resize(mddev->bitmap, newsize, 0, 0);
2921                 if (ret)
2922                         return ret;
2923         }
2924         md_set_array_sectors(mddev, newsize);
2925         set_capacity(mddev->gendisk, mddev->array_sectors);
2926         revalidate_disk(mddev->gendisk);
2927         if (sectors > mddev->dev_sectors &&
2928             mddev->recovery_cp > mddev->dev_sectors) {
2929                 mddev->recovery_cp = mddev->dev_sectors;
2930                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2931         }
2932         mddev->dev_sectors = sectors;
2933         mddev->resync_max_sectors = sectors;
2934         return 0;
2935 }
2936
2937 static int raid1_reshape(struct mddev *mddev)
2938 {
2939         /* We need to:
2940          * 1/ resize the r1bio_pool
2941          * 2/ resize conf->mirrors
2942          *
2943          * We allocate a new r1bio_pool if we can.
2944          * Then raise a device barrier and wait until all IO stops.
2945          * Then resize conf->mirrors and swap in the new r1bio pool.
2946          *
2947          * At the same time, we "pack" the devices so that all the missing
2948          * devices have the higher raid_disk numbers.
2949          */
2950         mempool_t *newpool, *oldpool;
2951         struct pool_info *newpoolinfo;
2952         struct raid1_info *newmirrors;
2953         struct r1conf *conf = mddev->private;
2954         int cnt, raid_disks;
2955         unsigned long flags;
2956         int d, d2, err;
2957
2958         /* Cannot change chunk_size, layout, or level */
2959         if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
2960             mddev->layout != mddev->new_layout ||
2961             mddev->level != mddev->new_level) {
2962                 mddev->new_chunk_sectors = mddev->chunk_sectors;
2963                 mddev->new_layout = mddev->layout;
2964                 mddev->new_level = mddev->level;
2965                 return -EINVAL;
2966         }
2967
2968         err = md_allow_write(mddev);
2969         if (err)
2970                 return err;
2971
2972         raid_disks = mddev->raid_disks + mddev->delta_disks;
2973
2974         if (raid_disks < conf->raid_disks) {
2975                 cnt=0;
2976                 for (d= 0; d < conf->raid_disks; d++)
2977                         if (conf->mirrors[d].rdev)
2978                                 cnt++;
2979                 if (cnt > raid_disks)
2980                         return -EBUSY;
2981         }
2982
2983         newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
2984         if (!newpoolinfo)
2985                 return -ENOMEM;
2986         newpoolinfo->mddev = mddev;
2987         newpoolinfo->raid_disks = raid_disks * 2;
2988
2989         newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2990                                  r1bio_pool_free, newpoolinfo);
2991         if (!newpool) {
2992                 kfree(newpoolinfo);
2993                 return -ENOMEM;
2994         }
2995         newmirrors = kzalloc(sizeof(struct raid1_info) * raid_disks * 2,
2996                              GFP_KERNEL);
2997         if (!newmirrors) {
2998                 kfree(newpoolinfo);
2999                 mempool_destroy(newpool);
3000                 return -ENOMEM;
3001         }
3002
3003         freeze_array(conf, 0);
3004
3005         /* ok, everything is stopped */
3006         oldpool = conf->r1bio_pool;
3007         conf->r1bio_pool = newpool;
3008
3009         for (d = d2 = 0; d < conf->raid_disks; d++) {
3010                 struct md_rdev *rdev = conf->mirrors[d].rdev;
3011                 if (rdev && rdev->raid_disk != d2) {
3012                         sysfs_unlink_rdev(mddev, rdev);
3013                         rdev->raid_disk = d2;
3014                         sysfs_unlink_rdev(mddev, rdev);
3015                         if (sysfs_link_rdev(mddev, rdev))
3016                                 printk(KERN_WARNING
3017                                        "md/raid1:%s: cannot register rd%d\n",
3018                                        mdname(mddev), rdev->raid_disk);
3019                 }
3020                 if (rdev)
3021                         newmirrors[d2++].rdev = rdev;
3022         }
3023         kfree(conf->mirrors);
3024         conf->mirrors = newmirrors;
3025         kfree(conf->poolinfo);
3026         conf->poolinfo = newpoolinfo;
3027
3028         spin_lock_irqsave(&conf->device_lock, flags);
3029         mddev->degraded += (raid_disks - conf->raid_disks);
3030         spin_unlock_irqrestore(&conf->device_lock, flags);
3031         conf->raid_disks = mddev->raid_disks = raid_disks;
3032         mddev->delta_disks = 0;
3033
3034         unfreeze_array(conf);
3035
3036         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3037         md_wakeup_thread(mddev->thread);
3038
3039         mempool_destroy(oldpool);
3040         return 0;
3041 }
3042
3043 static void raid1_quiesce(struct mddev *mddev, int state)
3044 {
3045         struct r1conf *conf = mddev->private;
3046
3047         switch(state) {
3048         case 2: /* wake for suspend */
3049                 wake_up(&conf->wait_barrier);
3050                 break;
3051         case 1:
3052                 raise_barrier(conf);
3053                 break;
3054         case 0:
3055                 lower_barrier(conf);
3056                 break;
3057         }
3058 }
3059
3060 static void *raid1_takeover(struct mddev *mddev)
3061 {
3062         /* raid1 can take over:
3063          *  raid5 with 2 devices, any layout or chunk size
3064          */
3065         if (mddev->level == 5 && mddev->raid_disks == 2) {
3066                 struct r1conf *conf;
3067                 mddev->new_level = 1;
3068                 mddev->new_layout = 0;
3069                 mddev->new_chunk_sectors = 0;
3070                 conf = setup_conf(mddev);
3071                 if (!IS_ERR(conf))
3072                         conf->barrier = 1;
3073                 return conf;
3074         }
3075         return ERR_PTR(-EINVAL);
3076 }
3077
3078 static struct md_personality raid1_personality =
3079 {
3080         .name           = "raid1",
3081         .level          = 1,
3082         .owner          = THIS_MODULE,
3083         .make_request   = make_request,
3084         .run            = run,
3085         .stop           = stop,
3086         .status         = status,
3087         .error_handler  = error,
3088         .hot_add_disk   = raid1_add_disk,
3089         .hot_remove_disk= raid1_remove_disk,
3090         .spare_active   = raid1_spare_active,
3091         .sync_request   = sync_request,
3092         .resize         = raid1_resize,
3093         .size           = raid1_size,
3094         .check_reshape  = raid1_reshape,
3095         .quiesce        = raid1_quiesce,
3096         .takeover       = raid1_takeover,
3097 };
3098
3099 static int __init raid_init(void)
3100 {
3101         return register_md_personality(&raid1_personality);
3102 }
3103
3104 static void raid_exit(void)
3105 {
3106         unregister_md_personality(&raid1_personality);
3107 }
3108
3109 module_init(raid_init);
3110 module_exit(raid_exit);
3111 MODULE_LICENSE("GPL");
3112 MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
3113 MODULE_ALIAS("md-personality-3"); /* RAID1 */
3114 MODULE_ALIAS("md-raid1");
3115 MODULE_ALIAS("md-level-1");
3116
3117 module_param(max_queued_requests, int, S_IRUGO|S_IWUSR);