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