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