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                         );
 869                 conf->nr_waiting--;
 870         }
 871         conf->nr_pending++;
 872         spin_unlock_irq(&conf->resync_lock);
 873 }
 874
 875 static void allow_barrier(struct r1conf *conf)
 876 {
 877         unsigned long flags;
 878         spin_lock_irqsave(&conf->resync_lock, flags);
 879         conf->nr_pending--;
 880         spin_unlock_irqrestore(&conf->resync_lock, flags);
 881         wake_up(&conf->wait_barrier);
 882 }
 883
 884 static void freeze_array(struct r1conf *conf)
 885 {
 886         /* stop syncio and normal IO and wait for everything to
 887          * go quite.
 888          * We increment barrier and nr_waiting, and then
 889          * wait until nr_pending match nr_queued+1
 890          * This is called in the context of one normal IO request
 891          * that has failed. Thus any sync request that might be pending
 892          * will be blocked by nr_pending, and we need to wait for
 893          * pending IO requests to complete or be queued for re-try.
 894          * Thus the number queued (nr_queued) plus this request (1)
 895          * must match the number of pending IOs (nr_pending) before
 896          * we continue.
 897          */
 898         spin_lock_irq(&conf->resync_lock);
 899         conf->barrier++;
 900         conf->nr_waiting++;
 901         wait_event_lock_irq(conf->wait_barrier,
 902                             conf->nr_pending == conf->nr_queued+1,
 903                             conf->resync_lock,
 904                             flush_pending_writes(conf));
 905         spin_unlock_irq(&conf->resync_lock);
 906 }
 907 static void unfreeze_array(struct r1conf *conf)
 908 {
 909         /* reverse the effect of the freeze */
 910         spin_lock_irq(&conf->resync_lock);
 911         conf->barrier--;
 912         conf->nr_waiting--;
 913         wake_up(&conf->wait_barrier);
 914         spin_unlock_irq(&conf->resync_lock);
 915 }
 916
 917
 918 /* duplicate the data pages for behind I/O
 919  */
 920 static void alloc_behind_pages(struct bio *bio, struct r1bio *r1_bio)
 921 {
 922         int i;
 923         struct bio_vec *bvec;
 924         struct bio_vec *bvecs = kzalloc(bio->bi_vcnt * sizeof(struct bio_vec),
 925                                         GFP_NOIO);
 926         if (unlikely(!bvecs))
 927                 return;
 928
 929         bio_for_each_segment(bvec, bio, i) {
 930                 bvecs[i] = *bvec;
 931                 bvecs[i].bv_page = alloc_page(GFP_NOIO);
 932                 if (unlikely(!bvecs[i].bv_page))
 933                         goto do_sync_io;
 934                 memcpy(kmap(bvecs[i].bv_page) + bvec->bv_offset,
 935                        kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
 936                 kunmap(bvecs[i].bv_page);
 937                 kunmap(bvec->bv_page);
 938         }
 939         r1_bio->behind_bvecs = bvecs;
 940         r1_bio->behind_page_count = bio->bi_vcnt;
 941         set_bit(R1BIO_BehindIO, &r1_bio->state);
 942         return;
 943
 944 do_sync_io:
 945         for (i = 0; i < bio->bi_vcnt; i++)
 946                 if (bvecs[i].bv_page)
 947                         put_page(bvecs[i].bv_page);
 948         kfree(bvecs);
 949         pr_debug("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
 950 }
 951
 952 struct raid1_plug_cb {
 953         struct blk_plug_cb      cb;
 954         struct bio_list         pending;
 955         int                     pending_cnt;
 956 };
 957
 958 static void raid1_unplug(struct blk_plug_cb *cb, bool from_schedule)
 959 {
 960         struct raid1_plug_cb *plug = container_of(cb, struct raid1_plug_cb,
 961                                                   cb);
 962         struct mddev *mddev = plug->cb.data;
 963         struct r1conf *conf = mddev->private;
 964         struct bio *bio;
 965
 966         if (from_schedule || current->bio_list) {
 967                 spin_lock_irq(&conf->device_lock);
 968                 bio_list_merge(&conf->pending_bio_list, &plug->pending);
 969                 conf->pending_count += plug->pending_cnt;
 970                 spin_unlock_irq(&conf->device_lock);
 971                 md_wakeup_thread(mddev->thread);
 972                 kfree(plug);
 973                 return;
 974         }
 975
 976         /* we aren't scheduling, so we can do the write-out directly. */
 977         bio = bio_list_get(&plug->pending);
 978         bitmap_unplug(mddev->bitmap);
 979         wake_up(&conf->wait_barrier);
 980
 981         while (bio) { /* submit pending writes */
 982                 struct bio *next = bio->bi_next;
 983                 bio->bi_next = NULL;
 984                 generic_make_request(bio);
 985                 bio = next;
 986         }
 987         kfree(plug);
 988 }
 989
 990 static void make_request(struct mddev *mddev, struct bio * bio)
 991 {
 992         struct r1conf *conf = mddev->private;
 993         struct raid1_info *mirror;
 994         struct r1bio *r1_bio;
 995         struct bio *read_bio;
 996         int i, disks;
 997         struct bitmap *bitmap;
 998         unsigned long flags;
 999         const int rw = bio_data_dir(bio);
1000         const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
1001         const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA));
1002         const unsigned long do_discard = (bio->bi_rw
1003                                           & (REQ_DISCARD | REQ_SECURE));
1004         struct md_rdev *blocked_rdev;
1005         struct blk_plug_cb *cb;
1006         struct raid1_plug_cb *plug = NULL;
1007         int first_clone;
1008         int sectors_handled;
1009         int max_sectors;
1010
1011         /*
1012          * Register the new request and wait if the reconstruction
1013          * thread has put up a bar for new requests.
1014          * Continue immediately if no resync is active currently.
1015          */
1016
1017         md_write_start(mddev, bio); /* wait on superblock update early */
1018
1019         if (bio_data_dir(bio) == WRITE &&
1020             bio->bi_sector + bio->bi_size/512 > mddev->suspend_lo &&
1021             bio->bi_sector < mddev->suspend_hi) {
1022                 /* As the suspend_* range is controlled by
1023                  * userspace, we want an interruptible
1024                  * wait.
1025                  */
1026                 DEFINE_WAIT(w);
1027                 for (;;) {
1028                         flush_signals(current);
1029                         prepare_to_wait(&conf->wait_barrier,
1030                                         &w, TASK_INTERRUPTIBLE);
1031                         if (bio->bi_sector + bio->bi_size/512 <= mddev->suspend_lo ||
1032                             bio->bi_sector >= mddev->suspend_hi)
1033                                 break;
1034                         schedule();
1035                 }
1036                 finish_wait(&conf->wait_barrier, &w);
1037         }
1038
1039         wait_barrier(conf);
1040
1041         bitmap = mddev->bitmap;
1042
1043         /*
1044          * make_request() can abort the operation when READA is being
1045          * used and no empty request is available.
1046          *
1047          */
1048         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1049
1050         r1_bio->master_bio = bio;
1051         r1_bio->sectors = bio->bi_size >> 9;
1052         r1_bio->state = 0;
1053         r1_bio->mddev = mddev;
1054         r1_bio->sector = bio->bi_sector;
1055
1056         /* We might need to issue multiple reads to different
1057          * devices if there are bad blocks around, so we keep
1058          * track of the number of reads in bio->bi_phys_segments.
1059          * If this is 0, there is only one r1_bio and no locking
1060          * will be needed when requests complete.  If it is
1061          * non-zero, then it is the number of not-completed requests.
1062          */
1063         bio->bi_phys_segments = 0;
1064         clear_bit(BIO_SEG_VALID, &bio->bi_flags);
1065
1066         if (rw == READ) {
1067                 /*
1068                  * read balancing logic:
1069                  */
1070                 int rdisk;
1071
1072 read_again:
1073                 rdisk = read_balance(conf, r1_bio, &max_sectors);
1074
1075                 if (rdisk < 0) {
1076                         /* couldn't find anywhere to read from */
1077                         raid_end_bio_io(r1_bio);
1078                         return;
1079                 }
1080                 mirror = conf->mirrors + rdisk;
1081
1082                 if (test_bit(WriteMostly, &mirror->rdev->flags) &&
1083                     bitmap) {
1084                         /* Reading from a write-mostly device must
1085                          * take care not to over-take any writes
1086                          * that are 'behind'
1087                          */
1088                         wait_event(bitmap->behind_wait,
1089                                    atomic_read(&bitmap->behind_writes) == 0);
1090                 }
1091                 r1_bio->read_disk = rdisk;
1092
1093                 read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1094                 md_trim_bio(read_bio, r1_bio->sector - bio->bi_sector,
1095                             max_sectors);
1096
1097                 r1_bio->bios[rdisk] = read_bio;
1098
1099                 read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
1100                 read_bio->bi_bdev = mirror->rdev->bdev;
1101                 read_bio->bi_end_io = raid1_end_read_request;
1102                 read_bio->bi_rw = READ | do_sync;
1103                 read_bio->bi_private = r1_bio;
1104
1105                 if (max_sectors < r1_bio->sectors) {
1106                         /* could not read all from this device, so we will
1107                          * need another r1_bio.
1108                          */
1109
1110                         sectors_handled = (r1_bio->sector + max_sectors
1111                                            - bio->bi_sector);
1112                         r1_bio->sectors = max_sectors;
1113                         spin_lock_irq(&conf->device_lock);
1114                         if (bio->bi_phys_segments == 0)
1115                                 bio->bi_phys_segments = 2;
1116                         else
1117                                 bio->bi_phys_segments++;
1118                         spin_unlock_irq(&conf->device_lock);
1119                         /* Cannot call generic_make_request directly
1120                          * as that will be queued in __make_request
1121                          * and subsequent mempool_alloc might block waiting
1122                          * for it.  So hand bio over to raid1d.
1123                          */
1124                         reschedule_retry(r1_bio);
1125
1126                         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1127
1128                         r1_bio->master_bio = bio;
1129                         r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
1130                         r1_bio->state = 0;
1131                         r1_bio->mddev = mddev;
1132                         r1_bio->sector = bio->bi_sector + sectors_handled;
1133                         goto read_again;
1134                 } else
1135                         generic_make_request(read_bio);
1136                 return;
1137         }
1138
1139         /*
1140          * WRITE:
1141          */
1142         if (conf->pending_count >= max_queued_requests) {
1143                 md_wakeup_thread(mddev->thread);
1144                 wait_event(conf->wait_barrier,
1145                            conf->pending_count < max_queued_requests);
1146         }
1147         /* first select target devices under rcu_lock and
1148          * inc refcount on their rdev.  Record them by setting
1149          * bios[x] to bio
1150          * If there are known/acknowledged bad blocks on any device on
1151          * which we have seen a write error, we want to avoid writing those
1152          * blocks.
1153          * This potentially requires several writes to write around
1154          * the bad blocks.  Each set of writes gets it's own r1bio
1155          * with a set of bios attached.
1156          */
1157
1158         disks = conf->raid_disks * 2;
1159  retry_write:
1160         blocked_rdev = NULL;
1161         rcu_read_lock();
1162         max_sectors = r1_bio->sectors;
1163         for (i = 0;  i < disks; i++) {
1164                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1165                 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
1166                         atomic_inc(&rdev->nr_pending);
1167                         blocked_rdev = rdev;
1168                         break;
1169                 }
1170                 r1_bio->bios[i] = NULL;
1171                 if (!rdev || test_bit(Faulty, &rdev->flags)
1172                     || test_bit(Unmerged, &rdev->flags)) {
1173                         if (i < conf->raid_disks)
1174                                 set_bit(R1BIO_Degraded, &r1_bio->state);
1175                         continue;
1176                 }
1177
1178                 atomic_inc(&rdev->nr_pending);
1179                 if (test_bit(WriteErrorSeen, &rdev->flags)) {
1180                         sector_t first_bad;
1181                         int bad_sectors;
1182                         int is_bad;
1183
1184                         is_bad = is_badblock(rdev, r1_bio->sector,
1185                                              max_sectors,
1186                                              &first_bad, &bad_sectors);
1187                         if (is_bad < 0) {
1188                                 /* mustn't write here until the bad block is
1189                                  * acknowledged*/
1190                                 set_bit(BlockedBadBlocks, &rdev->flags);
1191                                 blocked_rdev = rdev;
1192                                 break;
1193                         }
1194                         if (is_bad && first_bad <= r1_bio->sector) {
1195                                 /* Cannot write here at all */
1196                                 bad_sectors -= (r1_bio->sector - first_bad);
1197                                 if (bad_sectors < max_sectors)
1198                                         /* mustn't write more than bad_sectors
1199                                          * to other devices yet
1200                                          */
1201                                         max_sectors = bad_sectors;
1202                                 rdev_dec_pending(rdev, mddev);
1203                                 /* We don't set R1BIO_Degraded as that
1204                                  * only applies if the disk is
1205                                  * missing, so it might be re-added,
1206                                  * and we want to know to recover this
1207                                  * chunk.
1208                                  * In this case the device is here,
1209                                  * and the fact that this chunk is not
1210                                  * in-sync is recorded in the bad
1211                                  * block log
1212                                  */
1213                                 continue;
1214                         }
1215                         if (is_bad) {
1216                                 int good_sectors = first_bad - r1_bio->sector;
1217                                 if (good_sectors < max_sectors)
1218                                         max_sectors = good_sectors;
1219                         }
1220                 }
1221                 r1_bio->bios[i] = bio;
1222         }
1223         rcu_read_unlock();
1224
1225         if (unlikely(blocked_rdev)) {
1226                 /* Wait for this device to become unblocked */
1227                 int j;
1228
1229                 for (j = 0; j < i; j++)
1230                         if (r1_bio->bios[j])
1231                                 rdev_dec_pending(conf->mirrors[j].rdev, mddev);
1232                 r1_bio->state = 0;
1233                 allow_barrier(conf);
1234                 md_wait_for_blocked_rdev(blocked_rdev, mddev);
1235                 wait_barrier(conf);
1236                 goto retry_write;
1237         }
1238
1239         if (max_sectors < r1_bio->sectors) {
1240                 /* We are splitting this write into multiple parts, so
1241                  * we need to prepare for allocating another r1_bio.
1242                  */
1243                 r1_bio->sectors = max_sectors;
1244                 spin_lock_irq(&conf->device_lock);
1245                 if (bio->bi_phys_segments == 0)
1246                         bio->bi_phys_segments = 2;
1247                 else
1248                         bio->bi_phys_segments++;
1249                 spin_unlock_irq(&conf->device_lock);
1250         }
1251         sectors_handled = r1_bio->sector + max_sectors - bio->bi_sector;
1252
1253         atomic_set(&r1_bio->remaining, 1);
1254         atomic_set(&r1_bio->behind_remaining, 0);
1255
1256         first_clone = 1;
1257         for (i = 0; i < disks; i++) {
1258                 struct bio *mbio;
1259                 if (!r1_bio->bios[i])
1260                         continue;
1261
1262                 mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1263                 md_trim_bio(mbio, r1_bio->sector - bio->bi_sector, max_sectors);
1264
1265                 if (first_clone) {
1266                         /* do behind I/O ?
1267                          * Not if there are too many, or cannot
1268                          * allocate memory, or a reader on WriteMostly
1269                          * is waiting for behind writes to flush */
1270                         if (bitmap &&
1271                             (atomic_read(&bitmap->behind_writes)
1272                              < mddev->bitmap_info.max_write_behind) &&
1273                             !waitqueue_active(&bitmap->behind_wait))
1274                                 alloc_behind_pages(mbio, r1_bio);
1275
1276                         bitmap_startwrite(bitmap, r1_bio->sector,
1277                                           r1_bio->sectors,
1278                                           test_bit(R1BIO_BehindIO,
1279                                                    &r1_bio->state));
1280                         first_clone = 0;
1281                 }
1282                 if (r1_bio->behind_bvecs) {
1283                         struct bio_vec *bvec;
1284                         int j;
1285
1286                         /* Yes, I really want the '__' version so that
1287                          * we clear any unused pointer in the io_vec, rather
1288                          * than leave them unchanged.  This is important
1289                          * because when we come to free the pages, we won't
1290                          * know the original bi_idx, so we just free
1291                          * them all
1292                          */
1293                         __bio_for_each_segment(bvec, mbio, j, 0)
1294                                 bvec->bv_page = r1_bio->behind_bvecs[j].bv_page;
1295                         if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
1296                                 atomic_inc(&r1_bio->behind_remaining);
1297                 }
1298
1299                 r1_bio->bios[i] = mbio;
1300
1301                 mbio->bi_sector = (r1_bio->sector +
1302                                    conf->mirrors[i].rdev->data_offset);
1303                 mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1304                 mbio->bi_end_io = raid1_end_write_request;
1305                 mbio->bi_rw = WRITE | do_flush_fua | do_sync | do_discard;
1306                 mbio->bi_private = r1_bio;
1307
1308                 atomic_inc(&r1_bio->remaining);
1309
1310                 cb = blk_check_plugged(raid1_unplug, mddev, sizeof(*plug));
1311                 if (cb)
1312                         plug = container_of(cb, struct raid1_plug_cb, cb);
1313                 else
1314                         plug = NULL;
1315                 spin_lock_irqsave(&conf->device_lock, flags);
1316                 if (plug) {
1317                         bio_list_add(&plug->pending, mbio);
1318                         plug->pending_cnt++;
1319                 } else {
1320                         bio_list_add(&conf->pending_bio_list, mbio);
1321                         conf->pending_count++;
1322                 }
1323                 spin_unlock_irqrestore(&conf->device_lock, flags);
1324                 if (!plug)
1325                         md_wakeup_thread(mddev->thread);
1326         }
1327         /* Mustn't call r1_bio_write_done before this next test,
1328          * as it could result in the bio being freed.
1329          */
1330         if (sectors_handled < (bio->bi_size >> 9)) {
1331                 r1_bio_write_done(r1_bio);
1332                 /* We need another r1_bio.  It has already been counted
1333                  * in bio->bi_phys_segments
1334                  */
1335                 r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1336                 r1_bio->master_bio = bio;
1337                 r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
1338                 r1_bio->state = 0;
1339                 r1_bio->mddev = mddev;
1340                 r1_bio->sector = bio->bi_sector + sectors_handled;
1341                 goto retry_write;
1342         }
1343
1344         r1_bio_write_done(r1_bio);
1345
1346         /* In case raid1d snuck in to freeze_array */
1347         wake_up(&conf->wait_barrier);
1348 }
1349
1350 static void status(struct seq_file *seq, struct mddev *mddev)
1351 {
1352         struct r1conf *conf = mddev->private;
1353         int i;
1354
1355         seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1356                    conf->raid_disks - mddev->degraded);
1357         rcu_read_lock();
1358         for (i = 0; i < conf->raid_disks; i++) {
1359                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1360                 seq_printf(seq, "%s",
1361                            rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1362         }
1363         rcu_read_unlock();
1364         seq_printf(seq, "]");
1365 }
1366
1367
1368 static void error(struct mddev *mddev, struct md_rdev *rdev)
1369 {
1370         char b[BDEVNAME_SIZE];
1371         struct r1conf *conf = mddev->private;
1372
1373         /*
1374          * If it is not operational, then we have already marked it as dead
1375          * else if it is the last working disks, ignore the error, let the
1376          * next level up know.
1377          * else mark the drive as failed
1378          */
1379         if (test_bit(In_sync, &rdev->flags)
1380             && (conf->raid_disks - mddev->degraded) == 1) {
1381                 /*
1382                  * Don't fail the drive, act as though we were just a
1383                  * normal single drive.
1384                  * However don't try a recovery from this drive as
1385                  * it is very likely to fail.
1386                  */
1387                 conf->recovery_disabled = mddev->recovery_disabled;
1388                 return;
1389         }
1390         set_bit(Blocked, &rdev->flags);
1391         if (test_and_clear_bit(In_sync, &rdev->flags)) {
1392                 unsigned long flags;
1393                 spin_lock_irqsave(&conf->device_lock, flags);
1394                 mddev->degraded++;
1395                 set_bit(Faulty, &rdev->flags);
1396                 spin_unlock_irqrestore(&conf->device_lock, flags);
1397                 /*
1398                  * if recovery is running, make sure it aborts.
1399                  */
1400                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1401         } else
1402                 set_bit(Faulty, &rdev->flags);
1403         set_bit(MD_CHANGE_DEVS, &mddev->flags);
1404         printk(KERN_ALERT
1405                "md/raid1:%s: Disk failure on %s, disabling device.\n"
1406                "md/raid1:%s: Operation continuing on %d devices.\n",
1407                mdname(mddev), bdevname(rdev->bdev, b),
1408                mdname(mddev), conf->raid_disks - mddev->degraded);
1409 }
1410
1411 static void print_conf(struct r1conf *conf)
1412 {
1413         int i;
1414
1415         printk(KERN_DEBUG "RAID1 conf printout:\n");
1416         if (!conf) {
1417                 printk(KERN_DEBUG "(!conf)\n");
1418                 return;
1419         }
1420         printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1421                 conf->raid_disks);
1422
1423         rcu_read_lock();
1424         for (i = 0; i < conf->raid_disks; i++) {
1425                 char b[BDEVNAME_SIZE];
1426                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1427                 if (rdev)
1428                         printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
1429                                i, !test_bit(In_sync, &rdev->flags),
1430                                !test_bit(Faulty, &rdev->flags),
1431                                bdevname(rdev->bdev,b));
1432         }
1433         rcu_read_unlock();
1434 }
1435
1436 static void close_sync(struct r1conf *conf)
1437 {
1438         wait_barrier(conf);
1439         allow_barrier(conf);
1440
1441         mempool_destroy(conf->r1buf_pool);
1442         conf->r1buf_pool = NULL;
1443 }
1444
1445 static int raid1_spare_active(struct mddev *mddev)
1446 {
1447         int i;
1448         struct r1conf *conf = mddev->private;
1449         int count = 0;
1450         unsigned long flags;
1451
1452         /*
1453          * Find all failed disks within the RAID1 configuration
1454          * and mark them readable.
1455          * Called under mddev lock, so rcu protection not needed.
1456          */
1457         for (i = 0; i < conf->raid_disks; i++) {
1458                 struct md_rdev *rdev = conf->mirrors[i].rdev;
1459                 struct md_rdev *repl = conf->mirrors[conf->raid_disks + i].rdev;
1460                 if (repl
1461                     && repl->recovery_offset == MaxSector
1462                     && !test_bit(Faulty, &repl->flags)
1463                     && !test_and_set_bit(In_sync, &repl->flags)) {
1464                         /* replacement has just become active */
1465                         if (!rdev ||
1466                             !test_and_clear_bit(In_sync, &rdev->flags))
1467                                 count++;
1468                         if (rdev) {
1469                                 /* Replaced device not technically
1470                                  * faulty, but we need to be sure
1471                                  * it gets removed and never re-added
1472                                  */
1473                                 set_bit(Faulty, &rdev->flags);
1474                                 sysfs_notify_dirent_safe(
1475                                         rdev->sysfs_state);
1476                         }
1477                 }
1478                 if (rdev
1479                     && !test_bit(Faulty, &rdev->flags)
1480                     && !test_and_set_bit(In_sync, &rdev->flags)) {
1481                         count++;
1482                         sysfs_notify_dirent_safe(rdev->sysfs_state);
1483                 }
1484         }
1485         spin_lock_irqsave(&conf->device_lock, flags);
1486         mddev->degraded -= count;
1487         spin_unlock_irqrestore(&conf->device_lock, flags);
1488
1489         print_conf(conf);
1490         return count;
1491 }
1492
1493
1494 static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
1495 {
1496         struct r1conf *conf = mddev->private;
1497         int err = -EEXIST;
1498         int mirror = 0;
1499         struct raid1_info *p;
1500         int first = 0;
1501         int last = conf->raid_disks - 1;
1502         struct request_queue *q = bdev_get_queue(rdev->bdev);
1503
1504         if (mddev->recovery_disabled == conf->recovery_disabled)
1505                 return -EBUSY;
1506
1507         if (rdev->raid_disk >= 0)
1508                 first = last = rdev->raid_disk;
1509
1510         if (q->merge_bvec_fn) {
1511                 set_bit(Unmerged, &rdev->flags);
1512                 mddev->merge_check_needed = 1;
1513         }
1514
1515         for (mirror = first; mirror <= last; mirror++) {
1516                 p = conf->mirrors+mirror;
1517                 if (!p->rdev) {
1518
1519                         disk_stack_limits(mddev->gendisk, rdev->bdev,
1520                                           rdev->data_offset << 9);
1521
1522                         p->head_position = 0;
1523                         rdev->raid_disk = mirror;
1524                         err = 0;
1525                         /* As all devices are equivalent, we don't need a full recovery
1526                          * if this was recently any drive of the array
1527                          */
1528                         if (rdev->saved_raid_disk < 0)
1529                                 conf->fullsync = 1;
1530                         rcu_assign_pointer(p->rdev, rdev);
1531                         break;
1532                 }
1533                 if (test_bit(WantReplacement, &p->rdev->flags) &&
1534                     p[conf->raid_disks].rdev == NULL) {
1535                         /* Add this device as a replacement */
1536                         clear_bit(In_sync, &rdev->flags);
1537                         set_bit(Replacement, &rdev->flags);
1538                         rdev->raid_disk = mirror;
1539                         err = 0;
1540                         conf->fullsync = 1;
1541                         rcu_assign_pointer(p[conf->raid_disks].rdev, rdev);
1542                         break;
1543                 }
1544         }
1545         if (err == 0 && test_bit(Unmerged, &rdev->flags)) {
1546                 /* Some requests might not have seen this new
1547                  * merge_bvec_fn.  We must wait for them to complete
1548                  * before merging the device fully.
1549                  * First we make sure any code which has tested
1550                  * our function has submitted the request, then
1551                  * we wait for all outstanding requests to complete.
1552                  */
1553                 synchronize_sched();
1554                 raise_barrier(conf);
1555                 lower_barrier(conf);
1556                 clear_bit(Unmerged, &rdev->flags);
1557         }
1558         md_integrity_add_rdev(rdev, mddev);
1559         if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
1560                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
1561         print_conf(conf);
1562         return err;
1563 }
1564
1565 static int raid1_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
1566 {
1567         struct r1conf *conf = mddev->private;
1568         int err = 0;
1569         int number = rdev->raid_disk;
1570         struct raid1_info *p = conf->mirrors + number;
1571
1572         if (rdev != p->rdev)
1573                 p = conf->mirrors + conf->raid_disks + number;
1574
1575         print_conf(conf);
1576         if (rdev == p->rdev) {
1577                 if (test_bit(In_sync, &rdev->flags) ||
1578                     atomic_read(&rdev->nr_pending)) {
1579                         err = -EBUSY;
1580                         goto abort;
1581                 }
1582                 /* Only remove non-faulty devices if recovery
1583                  * is not possible.
1584                  */
1585                 if (!test_bit(Faulty, &rdev->flags) &&
1586                     mddev->recovery_disabled != conf->recovery_disabled &&
1587                     mddev->degraded < conf->raid_disks) {
1588                         err = -EBUSY;
1589                         goto abort;
1590                 }
1591                 p->rdev = NULL;
1592                 synchronize_rcu();
1593                 if (atomic_read(&rdev->nr_pending)) {
1594                         /* lost the race, try later */
1595                         err = -EBUSY;
1596                         p->rdev = rdev;
1597                         goto abort;
1598                 } else if (conf->mirrors[conf->raid_disks + number].rdev) {
1599                         /* We just removed a device that is being replaced.
1600                          * Move down the replacement.  We drain all IO before
1601                          * doing this to avoid confusion.
1602                          */
1603                         struct md_rdev *repl =
1604                                 conf->mirrors[conf->raid_disks + number].rdev;
1605                         raise_barrier(conf);
1606                         clear_bit(Replacement, &repl->flags);
1607                         p->rdev = repl;
1608                         conf->mirrors[conf->raid_disks + number].rdev = NULL;
1609                         lower_barrier(conf);
1610                         clear_bit(WantReplacement, &rdev->flags);
1611                 } else
1612                         clear_bit(WantReplacement, &rdev->flags);
1613                 err = md_integrity_register(mddev);
1614         }
1615 abort:
1616
1617         print_conf(conf);
1618         return err;
1619 }
1620
1621
1622 static void end_sync_read(struct bio *bio, int error)
1623 {
1624         struct r1bio *r1_bio = bio->bi_private;
1625
1626         update_head_pos(r1_bio->read_disk, r1_bio);
1627
1628         /*
1629          * we have read a block, now it needs to be re-written,
1630          * or re-read if the read failed.
1631          * We don't do much here, just schedule handling by raid1d
1632          */
1633         if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1634                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1635
1636         if (atomic_dec_and_test(&r1_bio->remaining))
1637                 reschedule_retry(r1_bio);
1638 }
1639
1640 static void end_sync_write(struct bio *bio, int error)
1641 {
1642         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1643         struct r1bio *r1_bio = bio->bi_private;
1644         struct mddev *mddev = r1_bio->mddev;
1645         struct r1conf *conf = mddev->private;
1646         int mirror=0;
1647         sector_t first_bad;
1648         int bad_sectors;
1649
1650         mirror = find_bio_disk(r1_bio, bio);
1651
1652         if (!uptodate) {
1653                 sector_t sync_blocks = 0;
1654                 sector_t s = r1_bio->sector;
1655                 long sectors_to_go = r1_bio->sectors;
1656                 /* make sure these bits doesn't get cleared. */
1657                 do {
1658                         bitmap_end_sync(mddev->bitmap, s,
1659                                         &sync_blocks, 1);
1660                         s += sync_blocks;
1661                         sectors_to_go -= sync_blocks;
1662                 } while (sectors_to_go > 0);
1663                 set_bit(WriteErrorSeen,
1664                         &conf->mirrors[mirror].rdev->flags);
1665                 if (!test_and_set_bit(WantReplacement,
1666                                       &conf->mirrors[mirror].rdev->flags))
1667                         set_bit(MD_RECOVERY_NEEDED, &
1668                                 mddev->recovery);
1669                 set_bit(R1BIO_WriteError, &r1_bio->state);
1670         } else if (is_badblock(conf->mirrors[mirror].rdev,
1671                                r1_bio->sector,
1672                                r1_bio->sectors,
1673                                &first_bad, &bad_sectors) &&
1674                    !is_badblock(conf->mirrors[r1_bio->read_disk].rdev,
1675                                 r1_bio->sector,
1676                                 r1_bio->sectors,
1677                                 &first_bad, &bad_sectors)
1678                 )
1679                 set_bit(R1BIO_MadeGood, &r1_bio->state);
1680
1681         if (atomic_dec_and_test(&r1_bio->remaining)) {
1682                 int s = r1_bio->sectors;
1683                 if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
1684                     test_bit(R1BIO_WriteError, &r1_bio->state))
1685                         reschedule_retry(r1_bio);
1686                 else {
1687                         put_buf(r1_bio);
1688                         md_done_sync(mddev, s, uptodate);
1689                 }
1690         }
1691 }
1692
1693 static int r1_sync_page_io(struct md_rdev *rdev, sector_t sector,
1694                             int sectors, struct page *page, int rw)
1695 {
1696         if (sync_page_io(rdev, sector, sectors << 9, page, rw, false))
1697                 /* success */
1698                 return 1;
1699         if (rw == WRITE) {
1700                 set_bit(WriteErrorSeen, &rdev->flags);
1701                 if (!test_and_set_bit(WantReplacement,
1702                                       &rdev->flags))
1703                         set_bit(MD_RECOVERY_NEEDED, &
1704                                 rdev->mddev->recovery);
1705         }
1706         /* need to record an error - either for the block or the device */
1707         if (!rdev_set_badblocks(rdev, sector, sectors, 0))
1708                 md_error(rdev->mddev, rdev);
1709         return 0;
1710 }
1711
1712 static int fix_sync_read_error(struct r1bio *r1_bio)
1713 {
1714         /* Try some synchronous reads of other devices to get
1715          * good data, much like with normal read errors.  Only
1716          * read into the pages we already have so we don't
1717          * need to re-issue the read request.
1718          * We don't need to freeze the array, because being in an
1719          * active sync request, there is no normal IO, and
1720          * no overlapping syncs.
1721          * We don't need to check is_badblock() again as we
1722          * made sure that anything with a bad block in range
1723          * will have bi_end_io clear.
1724          */
1725         struct mddev *mddev = r1_bio->mddev;
1726         struct r1conf *conf = mddev->private;
1727         struct bio *bio = r1_bio->bios[r1_bio->read_disk];
1728         sector_t sect = r1_bio->sector;
1729         int sectors = r1_bio->sectors;
1730         int idx = 0;
1731
1732         while(sectors) {
1733                 int s = sectors;
1734                 int d = r1_bio->read_disk;
1735                 int success = 0;
1736                 struct md_rdev *rdev;
1737                 int start;
1738
1739                 if (s > (PAGE_SIZE>>9))
1740                         s = PAGE_SIZE >> 9;
1741                 do {
1742                         if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1743                                 /* No rcu protection needed here devices
1744                                  * can only be removed when no resync is
1745                                  * active, and resync is currently active
1746                                  */
1747                                 rdev = conf->mirrors[d].rdev;
1748                                 if (sync_page_io(rdev, sect, s<<9,
1749                                                  bio->bi_io_vec[idx].bv_page,
1750                                                  READ, false)) {
1751                                         success = 1;
1752                                         break;
1753                                 }
1754                         }
1755                         d++;
1756                         if (d == conf->raid_disks * 2)
1757                                 d = 0;
1758                 } while (!success && d != r1_bio->read_disk);
1759
1760                 if (!success) {
1761                         char b[BDEVNAME_SIZE];
1762                         int abort = 0;
1763                         /* Cannot read from anywhere, this block is lost.
1764                          * Record a bad block on each device.  If that doesn't
1765                          * work just disable and interrupt the recovery.
1766                          * Don't fail devices as that won't really help.
1767                          */
1768                         printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O read error"
1769                                " for block %llu\n",
1770                                mdname(mddev),
1771                                bdevname(bio->bi_bdev, b),
1772                                (unsigned long long)r1_bio->sector);
1773                         for (d = 0; d < conf->raid_disks * 2; d++) {
1774                                 rdev = conf->mirrors[d].rdev;
1775                                 if (!rdev || test_bit(Faulty, &rdev->flags))
1776                                         continue;
1777                                 if (!rdev_set_badblocks(rdev, sect, s, 0))
1778                                         abort = 1;
1779                         }
1780                         if (abort) {
1781                                 conf->recovery_disabled =
1782                                         mddev->recovery_disabled;
1783                                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1784                                 md_done_sync(mddev, r1_bio->sectors, 0);
1785                                 put_buf(r1_bio);
1786                                 return 0;
1787                         }
1788                         /* Try next page */
1789                         sectors -= s;
1790                         sect += s;
1791                         idx++;
1792                         continue;
1793                 }
1794
1795                 start = d;
1796                 /* write it back and re-read */
1797                 while (d != r1_bio->read_disk) {
1798                         if (d == 0)
1799                                 d = conf->raid_disks * 2;
1800                         d--;
1801                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1802                                 continue;
1803                         rdev = conf->mirrors[d].rdev;
1804                         if (r1_sync_page_io(rdev, sect, s,
1805                                             bio->bi_io_vec[idx].bv_page,
1806                                             WRITE) == 0) {
1807                                 r1_bio->bios[d]->bi_end_io = NULL;
1808                                 rdev_dec_pending(rdev, mddev);
1809                         }
1810                 }
1811                 d = start;
1812                 while (d != r1_bio->read_disk) {
1813                         if (d == 0)
1814                                 d = conf->raid_disks * 2;
1815                         d--;
1816                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1817                                 continue;
1818                         rdev = conf->mirrors[d].rdev;
1819                         if (r1_sync_page_io(rdev, sect, s,
1820                                             bio->bi_io_vec[idx].bv_page,
1821                                             READ) != 0)
1822                                 atomic_add(s, &rdev->corrected_errors);
1823                 }
1824                 sectors -= s;
1825                 sect += s;
1826                 idx ++;
1827         }
1828         set_bit(R1BIO_Uptodate, &r1_bio->state);
1829         set_bit(BIO_UPTODATE, &bio->bi_flags);
1830         return 1;
1831 }
1832
1833 static int process_checks(struct r1bio *r1_bio)
1834 {
1835         /* We have read all readable devices.  If we haven't
1836          * got the block, then there is no hope left.
1837          * If we have, then we want to do a comparison
1838          * and skip the write if everything is the same.
1839          * If any blocks failed to read, then we need to
1840          * attempt an over-write
1841          */
1842         struct mddev *mddev = r1_bio->mddev;
1843         struct r1conf *conf = mddev->private;
1844         int primary;
1845         int i;
1846         int vcnt;
1847
1848         for (primary = 0; primary < conf->raid_disks * 2; primary++)
1849                 if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1850                     test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
1851                         r1_bio->bios[primary]->bi_end_io = NULL;
1852                         rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1853                         break;
1854                 }
1855         r1_bio->read_disk = primary;
1856         vcnt = (r1_bio->sectors + PAGE_SIZE / 512 - 1) >> (PAGE_SHIFT - 9);
1857         for (i = 0; i < conf->raid_disks * 2; i++) {
1858                 int j;
1859                 struct bio *pbio = r1_bio->bios[primary];
1860                 struct bio *sbio = r1_bio->bios[i];
1861                 int size;
1862
1863                 if (r1_bio->bios[i]->bi_end_io != end_sync_read)
1864                         continue;
1865
1866                 if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
1867                         for (j = vcnt; j-- ; ) {
1868                                 struct page *p, *s;
1869                                 p = pbio->bi_io_vec[j].bv_page;
1870                                 s = sbio->bi_io_vec[j].bv_page;
1871                                 if (memcmp(page_address(p),
1872                                            page_address(s),
1873                                            sbio->bi_io_vec[j].bv_len))
1874                                         break;
1875                         }
1876                 } else
1877                         j = 0;
1878                 if (j >= 0)
1879                         atomic64_add(r1_bio->sectors, &mddev->resync_mismatches);
1880                 if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
1881                               && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
1882                         /* No need to write to this device. */
1883                         sbio->bi_end_io = NULL;
1884                         rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1885                         continue;
1886                 }
1887                 /* fixup the bio for reuse */
1888                 sbio->bi_vcnt = vcnt;
1889                 sbio->bi_size = r1_bio->sectors << 9;
1890                 sbio->bi_idx = 0;
1891                 sbio->bi_phys_segments = 0;
1892                 sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1893                 sbio->bi_flags |= 1 << BIO_UPTODATE;
1894                 sbio->bi_next = NULL;
1895                 sbio->bi_sector = r1_bio->sector +
1896                         conf->mirrors[i].rdev->data_offset;
1897                 sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1898                 size = sbio->bi_size;
1899                 for (j = 0; j < vcnt ; j++) {
1900                         struct bio_vec *bi;
1901                         bi = &sbio->bi_io_vec[j];
1902                         bi->bv_offset = 0;
1903                         if (size > PAGE_SIZE)
1904                                 bi->bv_len = PAGE_SIZE;
1905                         else
1906                                 bi->bv_len = size;
1907                         size -= PAGE_SIZE;
1908                         memcpy(page_address(bi->bv_page),
1909                                page_address(pbio->bi_io_vec[j].bv_page),
1910                                PAGE_SIZE);
1911                 }
1912         }
1913         return 0;
1914 }
1915
1916 static void sync_request_write(struct mddev *mddev, struct r1bio *r1_bio)
1917 {
1918         struct r1conf *conf = mddev->private;
1919         int i;
1920         int disks = conf->raid_disks * 2;
1921         struct bio *bio, *wbio;
1922
1923         bio = r1_bio->bios[r1_bio->read_disk];
1924
1925         if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
1926                 /* ouch - failed to read all of that. */
1927                 if (!fix_sync_read_error(r1_bio))
1928                         return;
1929
1930         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1931                 if (process_checks(r1_bio) < 0)
1932                         return;
1933         /*
1934          * schedule writes
1935          */
1936         atomic_set(&r1_bio->remaining, 1);
1937         for (i = 0; i < disks ; i++) {
1938                 wbio = r1_bio->bios[i];
1939                 if (wbio->bi_end_io == NULL ||
1940                     (wbio->bi_end_io == end_sync_read &&
1941                      (i == r1_bio->read_disk ||
1942                       !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
1943                         continue;
1944
1945                 wbio->bi_rw = WRITE;
1946                 wbio->bi_end_io = end_sync_write;
1947                 atomic_inc(&r1_bio->remaining);
1948                 md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1949
1950                 generic_make_request(wbio);
1951         }
1952
1953         if (atomic_dec_and_test(&r1_bio->remaining)) {
1954                 /* if we're here, all write(s) have completed, so clean up */
1955                 int s = r1_bio->sectors;
1956                 if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
1957                     test_bit(R1BIO_WriteError, &r1_bio->state))
1958                         reschedule_retry(r1_bio);
1959                 else {
1960                         put_buf(r1_bio);
1961                         md_done_sync(mddev, s, 1);
1962                 }
1963         }
1964 }
1965
1966 /*
1967  * This is a kernel thread which:
1968  *
1969  *      1.      Retries failed read operations on working mirrors.
1970  *      2.      Updates the raid superblock when problems encounter.
1971  *      3.      Performs writes following reads for array synchronising.
1972  */
1973
1974 static void fix_read_error(struct r1conf *conf, int read_disk,
1975                            sector_t sect, int sectors)
1976 {
1977         struct mddev *mddev = conf->mddev;
1978         while(sectors) {
1979                 int s = sectors;
1980                 int d = read_disk;
1981                 int success = 0;
1982                 int start;
1983                 struct md_rdev *rdev;
1984
1985                 if (s > (PAGE_SIZE>>9))
1986                         s = PAGE_SIZE >> 9;
1987
1988                 do {
1989                         /* Note: no rcu protection needed here
1990                          * as this is synchronous in the raid1d thread
1991                          * which is the thread that might remove
1992                          * a device.  If raid1d ever becomes multi-threaded....
1993                          */
1994                         sector_t first_bad;
1995                         int bad_sectors;
1996
1997                         rdev = conf->mirrors[d].rdev;
1998                         if (rdev &&
1999                             (test_bit(In_sync, &rdev->flags) ||
2000                              (!test_bit(Faulty, &rdev->flags) &&
2001                               rdev->recovery_offset >= sect + s)) &&
2002                             is_badblock(rdev, sect, s,
2003                                         &first_bad, &bad_sectors) == 0 &&
2004                             sync_page_io(rdev, sect, s<<9,
2005                                          conf->tmppage, READ, false))
2006                                 success = 1;
2007                         else {
2008                                 d++;
2009                                 if (d == conf->raid_disks * 2)
2010                                         d = 0;
2011                         }
2012                 } while (!success && d != read_disk);
2013
2014                 if (!success) {
2015                         /* Cannot read from anywhere - mark it bad */
2016                         struct md_rdev *rdev = conf->mirrors[read_disk].rdev;
2017                         if (!rdev_set_badblocks(rdev, sect, s, 0))
2018                                 md_error(mddev, rdev);
2019                         break;
2020                 }
2021                 /* write it back and re-read */
2022                 start = d;
2023                 while (d != read_disk) {
2024                         if (d==0)
2025                                 d = conf->raid_disks * 2;
2026                         d--;
2027                         rdev = conf->mirrors[d].rdev;
2028                         if (rdev &&
2029                             test_bit(In_sync, &rdev->flags))
2030                                 r1_sync_page_io(rdev, sect, s,
2031                                                 conf->tmppage, WRITE);
2032                 }
2033                 d = start;
2034                 while (d != read_disk) {
2035                         char b[BDEVNAME_SIZE];
2036                         if (d==0)
2037                                 d = conf->raid_disks * 2;
2038                         d--;
2039                         rdev = conf->mirrors[d].rdev;
2040                         if (rdev &&
2041                             test_bit(In_sync, &rdev->flags)) {
2042                                 if (r1_sync_page_io(rdev, sect, s,
2043                                                     conf->tmppage, READ)) {
2044                                         atomic_add(s, &rdev->corrected_errors);
2045                                         printk(KERN_INFO
2046                                                "md/raid1:%s: read error corrected "
2047                                                "(%d sectors at %llu on %s)\n",
2048                                                mdname(mddev), s,
2049                                                (unsigned long long)(sect +
2050                                                    rdev->data_offset),
2051                                                bdevname(rdev->bdev, b));
2052                                 }
2053                         }
2054                 }
2055                 sectors -= s;
2056                 sect += s;
2057         }
2058 }
2059
2060 static void bi_complete(struct bio *bio, int error)
2061 {
2062         complete((struct completion *)bio->bi_private);
2063 }
2064
2065 static int submit_bio_wait(int rw, struct bio *bio)
2066 {
2067         struct completion event;
2068         rw |= REQ_SYNC;
2069
2070         init_completion(&event);
2071         bio->bi_private = &event;
2072         bio->bi_end_io = bi_complete;
2073         submit_bio(rw, bio);
2074         wait_for_completion(&event);
2075
2076         return test_bit(BIO_UPTODATE, &bio->bi_flags);
2077 }
2078
2079 static int narrow_write_error(struct r1bio *r1_bio, int i)
2080 {
2081         struct mddev *mddev = r1_bio->mddev;
2082         struct r1conf *conf = mddev->private;
2083         struct md_rdev *rdev = conf->mirrors[i].rdev;
2084         int vcnt, idx;
2085         struct bio_vec *vec;
2086
2087         /* bio has the data to be written to device 'i' where
2088          * we just recently had a write error.
2089          * We repeatedly clone the bio and trim down to one block,
2090          * then try the write.  Where the write fails we record
2091          * a bad block.
2092          * It is conceivable that the bio doesn't exactly align with
2093          * blocks.  We must handle this somehow.
2094          *
2095          * We currently own a reference on the rdev.
2096          */
2097
2098         int block_sectors;
2099         sector_t sector;
2100         int sectors;
2101         int sect_to_write = r1_bio->sectors;
2102         int ok = 1;
2103
2104         if (rdev->badblocks.shift < 0)
2105                 return 0;
2106
2107         block_sectors = 1 << rdev->badblocks.shift;
2108         sector = r1_bio->sector;
2109         sectors = ((sector + block_sectors)
2110                    & ~(sector_t)(block_sectors - 1))
2111                 - sector;
2112
2113         if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
2114                 vcnt = r1_bio->behind_page_count;
2115                 vec = r1_bio->behind_bvecs;
2116                 idx = 0;
2117                 while (vec[idx].bv_page == NULL)
2118                         idx++;
2119         } else {
2120                 vcnt = r1_bio->master_bio->bi_vcnt;
2121                 vec = r1_bio->master_bio->bi_io_vec;
2122                 idx = r1_bio->master_bio->bi_idx;
2123         }
2124         while (sect_to_write) {
2125                 struct bio *wbio;
2126                 if (sectors > sect_to_write)
2127                         sectors = sect_to_write;
2128                 /* Write at 'sector' for 'sectors'*/
2129
2130                 wbio = bio_alloc_mddev(GFP_NOIO, vcnt, mddev);
2131                 memcpy(wbio->bi_io_vec, vec, vcnt * sizeof(struct bio_vec));
2132                 wbio->bi_sector = r1_bio->sector;
2133                 wbio->bi_rw = WRITE;
2134                 wbio->bi_vcnt = vcnt;
2135                 wbio->bi_size = r1_bio->sectors << 9;
2136                 wbio->bi_idx = idx;
2137
2138                 md_trim_bio(wbio, sector - r1_bio->sector, sectors);
2139                 wbio->bi_sector += rdev->data_offset;
2140                 wbio->bi_bdev = rdev->bdev;
2141                 if (submit_bio_wait(WRITE, wbio) == 0)
2142                         /* failure! */
2143                         ok = rdev_set_badblocks(rdev, sector,
2144                                                 sectors, 0)
2145                                 && ok;
2146
2147                 bio_put(wbio);
2148                 sect_to_write -= sectors;
2149                 sector += sectors;
2150                 sectors = block_sectors;
2151         }
2152         return ok;
2153 }
2154
2155 static void handle_sync_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2156 {
2157         int m;
2158         int s = r1_bio->sectors;
2159         for (m = 0; m < conf->raid_disks * 2 ; m++) {
2160                 struct md_rdev *rdev = conf->mirrors[m].rdev;
2161                 struct bio *bio = r1_bio->bios[m];
2162                 if (bio->bi_end_io == NULL)
2163                         continue;
2164                 if (test_bit(BIO_UPTODATE, &bio->bi_flags) &&
2165                     test_bit(R1BIO_MadeGood, &r1_bio->state)) {
2166                         rdev_clear_badblocks(rdev, r1_bio->sector, s, 0);
2167                 }
2168                 if (!test_bit(BIO_UPTODATE, &bio->bi_flags) &&
2169                     test_bit(R1BIO_WriteError, &r1_bio->state)) {
2170                         if (!rdev_set_badblocks(rdev, r1_bio->sector, s, 0))
2171                                 md_error(conf->mddev, rdev);
2172                 }
2173         }
2174         put_buf(r1_bio);
2175         md_done_sync(conf->mddev, s, 1);
2176 }
2177
2178 static void handle_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2179 {
2180         int m;
2181         for (m = 0; m < conf->raid_disks * 2 ; m++)
2182                 if (r1_bio->bios[m] == IO_MADE_GOOD) {
2183                         struct md_rdev *rdev = conf->mirrors[m].rdev;
2184                         rdev_clear_badblocks(rdev,
2185                                              r1_bio->sector,
2186                                              r1_bio->sectors, 0);
2187                         rdev_dec_pending(rdev, conf->mddev);
2188                 } else if (r1_bio->bios[m] != NULL) {
2189                         /* This drive got a write error.  We need to
2190                          * narrow down and record precise write
2191                          * errors.
2192                          */
2193                         if (!narrow_write_error(r1_bio, m)) {
2194                                 md_error(conf->mddev,
2195                                          conf->mirrors[m].rdev);
2196                                 /* an I/O failed, we can't clear the bitmap */
2197                                 set_bit(R1BIO_Degraded, &r1_bio->state);
2198                         }
2199                         rdev_dec_pending(conf->mirrors[m].rdev,
2200                                          conf->mddev);
2201                 }
2202         if (test_bit(R1BIO_WriteError, &r1_bio->state))
2203                 close_write(r1_bio);
2204         raid_end_bio_io(r1_bio);
2205 }
2206
2207 static void handle_read_error(struct r1conf *conf, struct r1bio *r1_bio)
2208 {
2209         int disk;
2210         int max_sectors;
2211         struct mddev *mddev = conf->mddev;
2212         struct bio *bio;
2213         char b[BDEVNAME_SIZE];
2214         struct md_rdev *rdev;
2215
2216         clear_bit(R1BIO_ReadError, &r1_bio->state);
2217         /* we got a read error. Maybe the drive is bad.  Maybe just
2218          * the block and we can fix it.
2219          * We freeze all other IO, and try reading the block from
2220          * other devices.  When we find one, we re-write
2221          * and check it that fixes the read error.
2222          * This is all done synchronously while the array is
2223          * frozen
2224          */
2225         if (mddev->ro == 0) {
2226                 freeze_array(conf);
2227                 fix_read_error(conf, r1_bio->read_disk,
2228                                r1_bio->sector, r1_bio->sectors);
2229                 unfreeze_array(conf);
2230         } else
2231                 md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
2232         rdev_dec_pending(conf->mirrors[r1_bio->read_disk].rdev, conf->mddev);
2233
2234         bio = r1_bio->bios[r1_bio->read_disk];
2235         bdevname(bio->bi_bdev, b);
2236 read_more:
2237         disk = read_balance(conf, r1_bio, &max_sectors);
2238         if (disk == -1) {
2239                 printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O"
2240                        " read error for block %llu\n",
2241                        mdname(mddev), b, (unsigned long long)r1_bio->sector);
2242                 raid_end_bio_io(r1_bio);
2243         } else {
2244                 const unsigned long do_sync
2245                         = r1_bio->master_bio->bi_rw & REQ_SYNC;
2246                 if (bio) {
2247                         r1_bio->bios[r1_bio->read_disk] =
2248                                 mddev->ro ? IO_BLOCKED : NULL;
2249                         bio_put(bio);
2250                 }
2251                 r1_bio->read_disk = disk;
2252                 bio = bio_clone_mddev(r1_bio->master_bio, GFP_NOIO, mddev);
2253                 md_trim_bio(bio, r1_bio->sector - bio->bi_sector, max_sectors);
2254                 r1_bio->bios[r1_bio->read_disk] = bio;
2255                 rdev = conf->mirrors[disk].rdev;
2256                 printk_ratelimited(KERN_ERR
2257                                    "md/raid1:%s: redirecting sector %llu"
2258                                    " to other mirror: %s\n",
2259                                    mdname(mddev),
2260                                    (unsigned long long)r1_bio->sector,
2261                                    bdevname(rdev->bdev, b));
2262                 bio->bi_sector = r1_bio->sector + rdev->data_offset;
2263                 bio->bi_bdev = rdev->bdev;
2264                 bio->bi_end_io = raid1_end_read_request;
2265                 bio->bi_rw = READ | do_sync;
2266                 bio->bi_private = r1_bio;
2267                 if (max_sectors < r1_bio->sectors) {
2268                         /* Drat - have to split this up more */
2269                         struct bio *mbio = r1_bio->master_bio;
2270                         int sectors_handled = (r1_bio->sector + max_sectors
2271                                                - mbio->bi_sector);
2272                         r1_bio->sectors = max_sectors;
2273                         spin_lock_irq(&conf->device_lock);
2274                         if (mbio->bi_phys_segments == 0)
2275                                 mbio->bi_phys_segments = 2;
2276                         else
2277                                 mbio->bi_phys_segments++;
2278                         spin_unlock_irq(&conf->device_lock);
2279                         generic_make_request(bio);
2280                         bio = NULL;
2281
2282                         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
2283
2284                         r1_bio->master_bio = mbio;
2285                         r1_bio->sectors = (mbio->bi_size >> 9)
2286                                           - sectors_handled;
2287                         r1_bio->state = 0;
2288                         set_bit(R1BIO_ReadError, &r1_bio->state);
2289                         r1_bio->mddev = mddev;
2290                         r1_bio->sector = mbio->bi_sector + sectors_handled;
2291
2292                         goto read_more;
2293                 } else
2294                         generic_make_request(bio);
2295         }
2296 }
2297
2298 static void raid1d(struct md_thread *thread)
2299 {
2300         struct mddev *mddev = thread->mddev;
2301         struct r1bio *r1_bio;
2302         unsigned long flags;
2303         struct r1conf *conf = mddev->private;
2304         struct list_head *head = &conf->retry_list;
2305         struct blk_plug plug;
2306
2307         md_check_recovery(mddev);
2308
2309         blk_start_plug(&plug);
2310         for (;;) {
2311
2312                 flush_pending_writes(conf);
2313
2314                 spin_lock_irqsave(&conf->device_lock, flags);
2315                 if (list_empty(head)) {
2316                         spin_unlock_irqrestore(&conf->device_lock, flags);
2317                         break;
2318                 }
2319                 r1_bio = list_entry(head->prev, struct r1bio, retry_list);
2320                 list_del(head->prev);
2321                 conf->nr_queued--;
2322                 spin_unlock_irqrestore(&conf->device_lock, flags);
2323
2324                 mddev = r1_bio->mddev;
2325                 conf = mddev->private;
2326                 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
2327                         if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2328                             test_bit(R1BIO_WriteError, &r1_bio->state))
2329                                 handle_sync_write_finished(conf, r1_bio);
2330                         else
2331                                 sync_request_write(mddev, r1_bio);
2332                 } else if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2333                            test_bit(R1BIO_WriteError, &r1_bio->state))
2334                         handle_write_finished(conf, r1_bio);
2335                 else if (test_bit(R1BIO_ReadError, &r1_bio->state))
2336                         handle_read_error(conf, r1_bio);
2337                 else
2338                         /* just a partial read to be scheduled from separate
2339                          * context
2340                          */
2341                         generic_make_request(r1_bio->bios[r1_bio->read_disk]);
2342
2343                 cond_resched();
2344                 if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
2345                         md_check_recovery(mddev);
2346         }
2347         blk_finish_plug(&plug);
2348 }
2349
2350
2351 static int init_resync(struct r1conf *conf)
2352 {
2353         int buffs;
2354
2355         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
2356         BUG_ON(conf->r1buf_pool);
2357         conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
2358                                           conf->poolinfo);
2359         if (!conf->r1buf_pool)
2360                 return -ENOMEM;
2361         conf->next_resync = 0;
2362         return 0;
2363 }
2364
2365 /*
2366  * perform a "sync" on one "block"
2367  *
2368  * We need to make sure that no normal I/O request - particularly write
2369  * requests - conflict with active sync requests.
2370  *
2371  * This is achieved by tracking pending requests and a 'barrier' concept
2372  * that can be installed to exclude normal IO requests.
2373  */
2374
2375 static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster)
2376 {
2377         struct r1conf *conf = mddev->private;
2378         struct r1bio *r1_bio;
2379         struct bio *bio;
2380         sector_t max_sector, nr_sectors;
2381         int disk = -1;
2382         int i;
2383         int wonly = -1;
2384         int write_targets = 0, read_targets = 0;
2385         sector_t sync_blocks;
2386         int still_degraded = 0;
2387         int good_sectors = RESYNC_SECTORS;
2388         int min_bad = 0; /* number of sectors that are bad in all devices */
2389
2390         if (!conf->r1buf_pool)
2391                 if (init_resync(conf))
2392                         return 0;
2393
2394         max_sector = mddev->dev_sectors;
2395         if (sector_nr >= max_sector) {
2396                 /* If we aborted, we need to abort the
2397                  * sync on the 'current' bitmap chunk (there will
2398                  * only be one in raid1 resync.
2399                  * We can find the current addess in mddev->curr_resync
2400                  */
2401                 if (mddev->curr_resync < max_sector) /* aborted */
2402                         bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
2403                                                 &sync_blocks, 1);
2404                 else /* completed sync */
2405                         conf->fullsync = 0;
2406
2407                 bitmap_close_sync(mddev->bitmap);
2408                 close_sync(conf);
2409                 return 0;
2410         }
2411
2412         if (mddev->bitmap == NULL &&
2413             mddev->recovery_cp == MaxSector &&
2414             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
2415             conf->fullsync == 0) {
2416                 *skipped = 1;
2417                 return max_sector - sector_nr;
2418         }
2419         /* before building a request, check if we can skip these blocks..
2420          * This call the bitmap_start_sync doesn't actually record anything
2421          */
2422         if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
2423             !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2424                 /* We can skip this block, and probably several more */
2425                 *skipped = 1;
2426                 return sync_blocks;
2427         }
2428         /*
2429          * If there is non-resync activity waiting for a turn,
2430          * and resync is going fast enough,
2431          * then let it though before starting on this new sync request.
2432          */
2433         if (!go_faster && conf->nr_waiting)
2434                 msleep_interruptible(1000);
2435
2436         bitmap_cond_end_sync(mddev->bitmap, sector_nr);
2437         r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
2438         raise_barrier(conf);
2439
2440         conf->next_resync = sector_nr;
2441
2442         rcu_read_lock();
2443         /*
2444          * If we get a correctably read error during resync or recovery,
2445          * we might want to read from a different device.  So we
2446          * flag all drives that could conceivably be read from for READ,
2447          * and any others (which will be non-In_sync devices) for WRITE.
2448          * If a read fails, we try reading from something else for which READ
2449          * is OK.
2450          */
2451
2452         r1_bio->mddev = mddev;
2453         r1_bio->sector = sector_nr;
2454         r1_bio->state = 0;
2455         set_bit(R1BIO_IsSync, &r1_bio->state);
2456
2457         for (i = 0; i < conf->raid_disks * 2; i++) {
2458                 struct md_rdev *rdev;
2459                 bio = r1_bio->bios[i];
2460
2461                 /* take from bio_init */
2462                 bio->bi_next = NULL;
2463                 bio->bi_flags &= ~(BIO_POOL_MASK-1);
2464                 bio->bi_flags |= 1 << BIO_UPTODATE;
2465                 bio->bi_rw = READ;
2466                 bio->bi_vcnt = 0;
2467                 bio->bi_idx = 0;
2468                 bio->bi_phys_segments = 0;
2469                 bio->bi_size = 0;
2470                 bio->bi_end_io = NULL;
2471                 bio->bi_private = NULL;
2472
2473                 rdev = rcu_dereference(conf->mirrors[i].rdev);
2474                 if (rdev == NULL ||
2475                     test_bit(Faulty, &rdev->flags)) {
2476                         if (i < conf->raid_disks)
2477                                 still_degraded = 1;
2478                 } else if (!test_bit(In_sync, &rdev->flags)) {
2479                         bio->bi_rw = WRITE;
2480                         bio->bi_end_io = end_sync_write;
2481                         write_targets ++;
2482                 } else {
2483                         /* may need to read from here */
2484                         sector_t first_bad = MaxSector;
2485                         int bad_sectors;
2486
2487                         if (is_badblock(rdev, sector_nr, good_sectors,
2488                                         &first_bad, &bad_sectors)) {
2489                                 if (first_bad > sector_nr)
2490                                         good_sectors = first_bad - sector_nr;
2491                                 else {
2492                                         bad_sectors -= (sector_nr - first_bad);
2493                                         if (min_bad == 0 ||
2494                                             min_bad > bad_sectors)
2495                                                 min_bad = bad_sectors;
2496                                 }
2497                         }
2498                         if (sector_nr < first_bad) {
2499                                 if (test_bit(WriteMostly, &rdev->flags)) {
2500                                         if (wonly < 0)
2501                                                 wonly = i;
2502                                 } else {
2503                                         if (disk < 0)
2504                                                 disk = i;
2505                                 }
2506                                 bio->bi_rw = READ;
2507                                 bio->bi_end_io = end_sync_read;
2508                                 read_targets++;
2509                         } else if (!test_bit(WriteErrorSeen, &rdev->flags) &&
2510                                 test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
2511                                 !test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) {
2512                                 /*
2513                                  * The device is suitable for reading (InSync),
2514                                  * but has bad block(s) here. Let's try to correct them,
2515                                  * if we are doing resync or repair. Otherwise, leave
2516                                  * this device alone for this sync request.
2517                                  */
2518                                 bio->bi_rw = WRITE;
2519                                 bio->bi_end_io = end_sync_write;
2520                                 write_targets++;
2521                         }
2522                 }
2523                 if (bio->bi_end_io) {
2524                         atomic_inc(&rdev->nr_pending);
2525                         bio->bi_sector = sector_nr + rdev->data_offset;
2526                         bio->bi_bdev = rdev->bdev;
2527                         bio->bi_private = r1_bio;
2528                 }
2529         }
2530         rcu_read_unlock();
2531         if (disk < 0)
2532                 disk = wonly;
2533         r1_bio->read_disk = disk;
2534
2535         if (read_targets == 0 && min_bad > 0) {
2536                 /* These sectors are bad on all InSync devices, so we
2537                  * need to mark them bad on all write targets
2538                  */
2539                 int ok = 1;
2540                 for (i = 0 ; i < conf->raid_disks * 2 ; i++)
2541                         if (r1_bio->bios[i]->bi_end_io == end_sync_write) {
2542                                 struct md_rdev *rdev = conf->mirrors[i].rdev;
2543                                 ok = rdev_set_badblocks(rdev, sector_nr,
2544                                                         min_bad, 0
2545                                         ) && ok;
2546                         }
2547                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
2548                 *skipped = 1;
2549                 put_buf(r1_bio);
2550
2551                 if (!ok) {
2552                         /* Cannot record the badblocks, so need to
2553                          * abort the resync.
2554                          * If there are multiple read targets, could just
2555                          * fail the really bad ones ???
2556                          */
2557                         conf->recovery_disabled = mddev->recovery_disabled;
2558                         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2559                         return 0;
2560                 } else
2561                         return min_bad;
2562
2563         }
2564         if (min_bad > 0 && min_bad < good_sectors) {
2565                 /* only resync enough to reach the next bad->good
2566                  * transition */
2567                 good_sectors = min_bad;
2568         }
2569
2570         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
2571                 /* extra read targets are also write targets */
2572                 write_targets += read_targets-1;
2573
2574         if (write_targets == 0 || read_targets == 0) {
2575                 /* There is nowhere to write, so all non-sync
2576                  * drives must be failed - so we are finished
2577                  */
2578                 sector_t rv;
2579                 if (min_bad > 0)
2580                         max_sector = sector_nr + min_bad;
2581                 rv = max_sector - sector_nr;
2582                 *skipped = 1;
2583                 put_buf(r1_bio);
2584                 return rv;
2585         }
2586
2587         if (max_sector > mddev->resync_max)
2588                 max_sector = mddev->resync_max; /* Don't do IO beyond here */
2589         if (max_sector > sector_nr + good_sectors)
2590                 max_sector = sector_nr + good_sectors;
2591         nr_sectors = 0;
2592         sync_blocks = 0;
2593         do {
2594                 struct page *page;
2595                 int len = PAGE_SIZE;
2596                 if (sector_nr + (len>>9) > max_sector)
2597                         len = (max_sector - sector_nr) << 9;
2598                 if (len == 0)
2599                         break;
2600                 if (sync_blocks == 0) {
2601                         if (!bitmap_start_sync(mddev->bitmap, sector_nr,
2602                                                &sync_blocks, still_degraded) &&
2603                             !conf->fullsync &&
2604                             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2605                                 break;
2606                         BUG_ON(sync_blocks < (PAGE_SIZE>>9));
2607                         if ((len >> 9) > sync_blocks)
2608                                 len = sync_blocks<<9;
2609                 }
2610
2611                 for (i = 0 ; i < conf->raid_disks * 2; i++) {
2612                         bio = r1_bio->bios[i];
2613                         if (bio->bi_end_io) {
2614                                 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
2615                                 if (bio_add_page(bio, page, len, 0) == 0) {
2616                                         /* stop here */
2617                                         bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
2618                                         while (i > 0) {
2619                                                 i--;
2620                                                 bio = r1_bio->bios[i];
2621                                                 if (bio->bi_end_io==NULL)
2622                                                         continue;
2623                                                 /* remove last page from this bio */
2624                                                 bio->bi_vcnt--;
2625                                                 bio->bi_size -= len;
2626                                                 bio->bi_flags &= ~(1<< BIO_SEG_VALID);
2627                                         }
2628                                         goto bio_full;
2629                                 }
2630                         }
2631                 }
2632                 nr_sectors += len>>9;
2633                 sector_nr += len>>9;
2634                 sync_blocks -= (len>>9);
2635         } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
2636  bio_full:
2637         r1_bio->sectors = nr_sectors;
2638
2639         /* For a user-requested sync, we read all readable devices and do a
2640          * compare
2641          */
2642         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2643                 atomic_set(&r1_bio->remaining, read_targets);
2644                 for (i = 0; i < conf->raid_disks * 2 && read_targets; i++) {
2645                         bio = r1_bio->bios[i];
2646                         if (bio->bi_end_io == end_sync_read) {
2647                                 read_targets--;
2648                                 md_sync_acct(bio->bi_bdev, nr_sectors);
2649                                 generic_make_request(bio);
2650                         }
2651                 }
2652         } else {
2653                 atomic_set(&r1_bio->remaining, 1);
2654                 bio = r1_bio->bios[r1_bio->read_disk];
2655                 md_sync_acct(bio->bi_bdev, nr_sectors);
2656                 generic_make_request(bio);
2657
2658         }
2659         return nr_sectors;
2660 }
2661
2662 static sector_t raid1_size(struct mddev *mddev, sector_t sectors, int raid_disks)
2663 {
2664         if (sectors)
2665                 return sectors;
2666
2667         return mddev->dev_sectors;
2668 }
2669
2670 static struct r1conf *setup_conf(struct mddev *mddev)
2671 {
2672         struct r1conf *conf;
2673         int i;
2674         struct raid1_info *disk;
2675         struct md_rdev *rdev;
2676         int err = -ENOMEM;
2677
2678         conf = kzalloc(sizeof(struct r1conf), GFP_KERNEL);
2679         if (!conf)
2680                 goto abort;
2681
2682         conf->mirrors = kzalloc(sizeof(struct raid1_info)
2683                                 * mddev->raid_disks * 2,
2684                                  GFP_KERNEL);
2685         if (!conf->mirrors)
2686                 goto abort;
2687
2688         conf->tmppage = alloc_page(GFP_KERNEL);
2689         if (!conf->tmppage)
2690                 goto abort;
2691
2692         conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
2693         if (!conf->poolinfo)
2694                 goto abort;
2695         conf->poolinfo->raid_disks = mddev->raid_disks * 2;
2696         conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2697                                           r1bio_pool_free,
2698                                           conf->poolinfo);
2699         if (!conf->r1bio_pool)
2700                 goto abort;
2701
2702         conf->poolinfo->mddev = mddev;
2703
2704         err = -EINVAL;
2705         spin_lock_init(&conf->device_lock);
2706         rdev_for_each(rdev, mddev) {
2707                 struct request_queue *q;
2708                 int disk_idx = rdev->raid_disk;
2709                 if (disk_idx >= mddev->raid_disks
2710                     || disk_idx < 0)
2711                         continue;
2712                 if (test_bit(Replacement, &rdev->flags))
2713                         disk = conf->mirrors + mddev->raid_disks + disk_idx;
2714                 else
2715                         disk = conf->mirrors + disk_idx;
2716
2717                 if (disk->rdev)
2718                         goto abort;
2719                 disk->rdev = rdev;
2720                 q = bdev_get_queue(rdev->bdev);
2721                 if (q->merge_bvec_fn)
2722                         mddev->merge_check_needed = 1;
2723
2724                 disk->head_position = 0;
2725                 disk->seq_start = MaxSector;
2726         }
2727         conf->raid_disks = mddev->raid_disks;
2728         conf->mddev = mddev;
2729         INIT_LIST_HEAD(&conf->retry_list);
2730
2731         spin_lock_init(&conf->resync_lock);
2732         init_waitqueue_head(&conf->wait_barrier);
2733
2734         bio_list_init(&conf->pending_bio_list);
2735         conf->pending_count = 0;
2736         conf->recovery_disabled = mddev->recovery_disabled - 1;
2737
2738         err = -EIO;
2739         for (i = 0; i < conf->raid_disks * 2; i++) {
2740
2741                 disk = conf->mirrors + i;
2742
2743                 if (i < conf->raid_disks &&
2744                     disk[conf->raid_disks].rdev) {
2745                         /* This slot has a replacement. */
2746                         if (!disk->rdev) {
2747                                 /* No original, just make the replacement
2748                                  * a recovering spare
2749                                  */
2750                                 disk->rdev =
2751                                         disk[conf->raid_disks].rdev;
2752                                 disk[conf->raid_disks].rdev = NULL;
2753                         } else if (!test_bit(In_sync, &disk->rdev->flags))
2754                                 /* Original is not in_sync - bad */
2755                                 goto abort;
2756                 }
2757
2758                 if (!disk->rdev ||
2759                     !test_bit(In_sync, &disk->rdev->flags)) {
2760                         disk->head_position = 0;
2761                         if (disk->rdev &&
2762                             (disk->rdev->saved_raid_disk < 0))
2763                                 conf->fullsync = 1;
2764                 }
2765         }
2766
2767         err = -ENOMEM;
2768         conf->thread = md_register_thread(raid1d, mddev, "raid1");
2769         if (!conf->thread) {
2770                 printk(KERN_ERR
2771                        "md/raid1:%s: couldn't allocate thread\n",
2772                        mdname(mddev));
2773                 goto abort;
2774         }
2775
2776         return conf;
2777
2778  abort:
2779         if (conf) {
2780                 if (conf->r1bio_pool)
2781                         mempool_destroy(conf->r1bio_pool);
2782                 kfree(conf->mirrors);
2783                 safe_put_page(conf->tmppage);
2784                 kfree(conf->poolinfo);
2785                 kfree(conf);
2786         }
2787         return ERR_PTR(err);
2788 }
2789
2790 static int stop(struct mddev *mddev);
2791 static int run(struct mddev *mddev)
2792 {
2793         struct r1conf *conf;
2794         int i;
2795         struct md_rdev *rdev;
2796         int ret;
2797         bool discard_supported = false;
2798
2799         if (mddev->level != 1) {
2800                 printk(KERN_ERR "md/raid1:%s: raid level not set to mirroring (%d)\n",
2801                        mdname(mddev), mddev->level);
2802                 return -EIO;
2803         }
2804         if (mddev->reshape_position != MaxSector) {
2805                 printk(KERN_ERR "md/raid1:%s: reshape_position set but not supported\n",
2806                        mdname(mddev));
2807                 return -EIO;
2808         }
2809         /*
2810          * copy the already verified devices into our private RAID1
2811          * bookkeeping area. [whatever we allocate in run(),
2812          * should be freed in stop()]
2813          */
2814         if (mddev->private == NULL)
2815                 conf = setup_conf(mddev);
2816         else
2817                 conf = mddev->private;
2818
2819         if (IS_ERR(conf))
2820                 return PTR_ERR(conf);
2821
2822         rdev_for_each(rdev, mddev) {
2823                 if (!mddev->gendisk)
2824                         continue;
2825                 disk_stack_limits(mddev->gendisk, rdev->bdev,
2826                                   rdev->data_offset << 9);
2827                 if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
2828                         discard_supported = true;
2829         }
2830
2831         mddev->degraded = 0;
2832         for (i=0; i < conf->raid_disks; i++)
2833                 if (conf->mirrors[i].rdev == NULL ||
2834                     !test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
2835                     test_bit(Faulty, &conf->mirrors[i].rdev->flags))
2836                         mddev->degraded++;
2837
2838         if (conf->raid_disks - mddev->degraded == 1)
2839                 mddev->recovery_cp = MaxSector;
2840
2841         if (mddev->recovery_cp != MaxSector)
2842                 printk(KERN_NOTICE "md/raid1:%s: not clean"
2843                        " -- starting background reconstruction\n",
2844                        mdname(mddev));
2845         printk(KERN_INFO
2846                 "md/raid1:%s: active with %d out of %d mirrors\n",
2847                 mdname(mddev), mddev->raid_disks - mddev->degraded,
2848                 mddev->raid_disks);
2849
2850         /*
2851          * Ok, everything is just fine now
2852          */
2853         mddev->thread = conf->thread;
2854         conf->thread = NULL;
2855         mddev->private = conf;
2856
2857         md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
2858
2859         if (mddev->queue) {
2860                 mddev->queue->backing_dev_info.congested_fn = raid1_congested;
2861                 mddev->queue->backing_dev_info.congested_data = mddev;
2862                 blk_queue_merge_bvec(mddev->queue, raid1_mergeable_bvec);
2863
2864                 if (discard_supported)
2865                         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
2866                                                 mddev->queue);
2867                 else
2868                         queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
2869                                                   mddev->queue);
2870         }
2871
2872         ret =  md_integrity_register(mddev);
2873         if (ret)
2874                 stop(mddev);
2875         return ret;
2876 }
2877
2878 static int stop(struct mddev *mddev)
2879 {
2880         struct r1conf *conf = mddev->private;
2881         struct bitmap *bitmap = mddev->bitmap;
2882
2883         /* wait for behind writes to complete */
2884         if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
2885                 printk(KERN_INFO "md/raid1:%s: behind writes in progress - waiting to stop.\n",
2886                        mdname(mddev));
2887                 /* need to kick something here to make sure I/O goes? */
2888                 wait_event(bitmap->behind_wait,
2889                            atomic_read(&bitmap->behind_writes) == 0);
2890         }
2891
2892         raise_barrier(conf);
2893         lower_barrier(conf);
2894
2895         md_unregister_thread(&mddev->thread);
2896         if (conf->r1bio_pool)
2897                 mempool_destroy(conf->r1bio_pool);
2898         kfree(conf->mirrors);
2899         kfree(conf->poolinfo);
2900         kfree(conf);
2901         mddev->private = NULL;
2902         return 0;
2903 }
2904
2905 static int raid1_resize(struct mddev *mddev, sector_t sectors)
2906 {
2907         /* no resync is happening, and there is enough space
2908          * on all devices, so we can resize.
2909          * We need to make sure resync covers any new space.
2910          * If the array is shrinking we should possibly wait until
2911          * any io in the removed space completes, but it hardly seems
2912          * worth it.
2913          */
2914         sector_t newsize = raid1_size(mddev, sectors, 0);
2915         if (mddev->external_size &&
2916             mddev->array_sectors > newsize)
2917                 return -EINVAL;
2918         if (mddev->bitmap) {
2919                 int ret = bitmap_resize(mddev->bitmap, newsize, 0, 0);
2920                 if (ret)
2921                         return ret;
2922         }
2923         md_set_array_sectors(mddev, newsize);
2924         set_capacity(mddev->gendisk, mddev->array_sectors);
2925         revalidate_disk(mddev->gendisk);
2926         if (sectors > mddev->dev_sectors &&
2927             mddev->recovery_cp > mddev->dev_sectors) {
2928                 mddev->recovery_cp = mddev->dev_sectors;
2929                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2930         }
2931         mddev->dev_sectors = sectors;
2932         mddev->resync_max_sectors = sectors;
2933         return 0;
2934 }
2935
2936 static int raid1_reshape(struct mddev *mddev)
2937 {
2938         /* We need to:
2939          * 1/ resize the r1bio_pool
2940          * 2/ resize conf->mirrors
2941          *
2942          * We allocate a new r1bio_pool if we can.
2943          * Then raise a device barrier and wait until all IO stops.
2944          * Then resize conf->mirrors and swap in the new r1bio pool.
2945          *
2946          * At the same time, we "pack" the devices so that all the missing
2947          * devices have the higher raid_disk numbers.
2948          */
2949         mempool_t *newpool, *oldpool;
2950         struct pool_info *newpoolinfo;
2951         struct raid1_info *newmirrors;
2952         struct r1conf *conf = mddev->private;
2953         int cnt, raid_disks;
2954         unsigned long flags;
2955         int d, d2, err;
2956
2957         /* Cannot change chunk_size, layout, or level */
2958         if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
2959             mddev->layout != mddev->new_layout ||
2960             mddev->level != mddev->new_level) {
2961                 mddev->new_chunk_sectors = mddev->chunk_sectors;
2962                 mddev->new_layout = mddev->layout;
2963                 mddev->new_level = mddev->level;
2964                 return -EINVAL;
2965         }
2966
2967         err = md_allow_write(mddev);
2968         if (err)
2969                 return err;
2970
2971         raid_disks = mddev->raid_disks + mddev->delta_disks;
2972
2973         if (raid_disks < conf->raid_disks) {
2974                 cnt=0;
2975                 for (d= 0; d < conf->raid_disks; d++)
2976                         if (conf->mirrors[d].rdev)
2977                                 cnt++;
2978                 if (cnt > raid_disks)
2979                         return -EBUSY;
2980         }
2981
2982         newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
2983         if (!newpoolinfo)
2984                 return -ENOMEM;
2985         newpoolinfo->mddev = mddev;
2986         newpoolinfo->raid_disks = raid_disks * 2;
2987
2988         newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2989                                  r1bio_pool_free, newpoolinfo);
2990         if (!newpool) {
2991                 kfree(newpoolinfo);
2992                 return -ENOMEM;
2993         }
2994         newmirrors = kzalloc(sizeof(struct raid1_info) * raid_disks * 2,
2995                              GFP_KERNEL);
2996         if (!newmirrors) {
2997                 kfree(newpoolinfo);
2998                 mempool_destroy(newpool);
2999                 return -ENOMEM;
3000         }
3001
3002         raise_barrier(conf);
3003
3004         /* ok, everything is stopped */
3005         oldpool = conf->r1bio_pool;
3006         conf->r1bio_pool = newpool;
3007
3008         for (d = d2 = 0; d < conf->raid_disks; d++) {
3009                 struct md_rdev *rdev = conf->mirrors[d].rdev;
3010                 if (rdev && rdev->raid_disk != d2) {
3011                         sysfs_unlink_rdev(mddev, rdev);
3012                         rdev->raid_disk = d2;
3013                         sysfs_unlink_rdev(mddev, rdev);
3014                         if (sysfs_link_rdev(mddev, rdev))
3015                                 printk(KERN_WARNING
3016                                        "md/raid1:%s: cannot register rd%d\n",
3017                                        mdname(mddev), rdev->raid_disk);
3018                 }
3019                 if (rdev)
3020                         newmirrors[d2++].rdev = rdev;
3021         }
3022         kfree(conf->mirrors);
3023         conf->mirrors = newmirrors;
3024         kfree(conf->poolinfo);
3025         conf->poolinfo = newpoolinfo;
3026
3027         spin_lock_irqsave(&conf->device_lock, flags);
3028         mddev->degraded += (raid_disks - conf->raid_disks);
3029         spin_unlock_irqrestore(&conf->device_lock, flags);
3030         conf->raid_disks = mddev->raid_disks = raid_disks;
3031         mddev->delta_disks = 0;
3032
3033         lower_barrier(conf);
3034
3035         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3036         md_wakeup_thread(mddev->thread);
3037
3038         mempool_destroy(oldpool);
3039         return 0;
3040 }
3041
3042 static void raid1_quiesce(struct mddev *mddev, int state)
3043 {
3044         struct r1conf *conf = mddev->private;
3045
3046         switch(state) {
3047         case 2: /* wake for suspend */
3048                 wake_up(&conf->wait_barrier);
3049                 break;
3050         case 1:
3051                 raise_barrier(conf);
3052                 break;
3053         case 0:
3054                 lower_barrier(conf);
3055                 break;
3056         }
3057 }
3058
3059 static void *raid1_takeover(struct mddev *mddev)
3060 {
3061         /* raid1 can take over:
3062          *  raid5 with 2 devices, any layout or chunk size
3063          */
3064         if (mddev->level == 5 && mddev->raid_disks == 2) {
3065                 struct r1conf *conf;
3066                 mddev->new_level = 1;
3067                 mddev->new_layout = 0;
3068                 mddev->new_chunk_sectors = 0;
3069                 conf = setup_conf(mddev);
3070                 if (!IS_ERR(conf))
3071                         conf->barrier = 1;
3072                 return conf;
3073         }
3074         return ERR_PTR(-EINVAL);
3075 }
3076
3077 static struct md_personality raid1_personality =
3078 {
3079         .name           = "raid1",
3080         .level          = 1,
3081         .owner          = THIS_MODULE,
3082         .make_request   = make_request,
3083         .run            = run,
3084         .stop           = stop,
3085         .status         = status,
3086         .error_handler  = error,
3087         .hot_add_disk   = raid1_add_disk,
3088         .hot_remove_disk= raid1_remove_disk,
3089         .spare_active   = raid1_spare_active,
3090         .sync_request   = sync_request,
3091         .resize         = raid1_resize,
3092         .size           = raid1_size,
3093         .check_reshape  = raid1_reshape,
3094         .quiesce        = raid1_quiesce,
3095         .takeover       = raid1_takeover,
3096 };
3097
3098 static int __init raid_init(void)
3099 {
3100         return register_md_personality(&raid1_personality);
3101 }
3102
3103 static void raid_exit(void)
3104 {
3105         unregister_md_personality(&raid1_personality);
3106 }
3107
3108 module_init(raid_init);
3109 module_exit(raid_exit);
3110 MODULE_LICENSE("GPL");
3111 MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
3112 MODULE_ALIAS("md-personality-3"); /* RAID1 */
3113 MODULE_ALIAS("md-raid1");
3114 MODULE_ALIAS("md-level-1");
3115
3116 module_param(max_queued_requests, int, S_IRUGO|S_IWUSR);