drivers/md/raid1.c

   1 /*
   2  * raid1.c : Multiple Devices driver for Linux
   3  *
   4  * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat
   5  *
   6  * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman
   7  *
   8  * RAID-1 management functions.
   9  *
  10  * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000
  11  *
  12  * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
  13  * Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
  14  *
  15  * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support
  16  * bitmapped intelligence in resync:
  17  *
  18  *      - bitmap marked during normal i/o
  19  *      - bitmap used to skip nondirty blocks during sync
  20  *
  21  * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology:
  22  * - persistent bitmap code
  23  *
  24  * This program is free software; you can redistribute it and/or modify
  25  * it under the terms of the GNU General Public License as published by
  26  * the Free Software Foundation; either version 2, or (at your option)
  27  * any later version.
  28  *
  29  * You should have received a copy of the GNU General Public License
  30  * (for example /usr/src/linux/COPYING); if not, write to the Free
  31  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  32  */
  33
  34 #include <linux/slab.h>
  35 #include <linux/delay.h>
  36 #include <linux/blkdev.h>
  37 #include <linux/module.h>
  38 #include <linux/seq_file.h>
  39 #include <linux/ratelimit.h>
  40 #include "md.h"
  41 #include "raid1.h"
  42 #include "bitmap.h"
  43
  44 /*
  45  * Number of guaranteed r1bios in case of extreme VM load:
  46  */
  47 #define NR_RAID1_BIOS 256
  48
  49 /* when we get a read error on a read-only array, we redirect to another
  50  * device without failing the first device, or trying to over-write to
  51  * correct the read error.  To keep track of bad blocks on a per-bio
  52  * level, we store IO_BLOCKED in the appropriate 'bios' pointer
  53  */
  54 #define IO_BLOCKED ((struct bio *)1)
  55 /* When we successfully write to a known bad-block, we need to remove the
  56  * bad-block marking which must be done from process context.  So we record
  57  * the success by setting devs[n].bio to IO_MADE_GOOD
  58  */
  59 #define IO_MADE_GOOD ((struct bio *)2)
  60
  61 #define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
  62
  63 /* When there are this many requests queue to be written by
  64  * the raid1 thread, we become 'congested' to provide back-pressure
  65  * for writeback.
  66  */
  67 static int max_queued_requests = 1024;
  68
  69 static void allow_barrier(struct r1conf *conf);
  70 static void lower_barrier(struct r1conf *conf);
  71
  72 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
  73 {
  74         struct pool_info *pi = data;
  75         int size = offsetof(struct r1bio, bios[pi->raid_disks]);
  76
  77         /* allocate a r1bio with room for raid_disks entries in the bios array */
  78         return kzalloc(size, gfp_flags);
  79 }
  80
  81 static void r1bio_pool_free(void *r1_bio, void *data)
  82 {
  83         kfree(r1_bio);
  84 }
  85
  86 #define RESYNC_BLOCK_SIZE (64*1024)
  87 //#define RESYNC_BLOCK_SIZE PAGE_SIZE
  88 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
  89 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
  90 #define RESYNC_WINDOW (2048*1024)
  91
  92 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
  93 {
  94         struct pool_info *pi = data;
  95         struct page *page;
  96         struct r1bio *r1_bio;
  97         struct bio *bio;
  98         int i, j;
  99
 100         r1_bio = r1bio_pool_alloc(gfp_flags, pi);
 101         if (!r1_bio)
 102                 return NULL;
 103
 104         /*
 105          * Allocate bios : 1 for reading, n-1 for writing
 106          */
 107         for (j = pi->raid_disks ; j-- ; ) {
 108                 bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
 109                 if (!bio)
 110                         goto out_free_bio;
 111                 r1_bio->bios[j] = bio;
 112         }
 113         /*
 114          * Allocate RESYNC_PAGES data pages and attach them to
 115          * the first bio.
 116          * If this is a user-requested check/repair, allocate
 117          * RESYNC_PAGES for each bio.
 118          */
 119         if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
 120                 j = pi->raid_disks;
 121         else
 122                 j = 1;
 123         while(j--) {
 124                 bio = r1_bio->bios[j];
 125                 for (i = 0; i < RESYNC_PAGES; i++) {
 126                         page = alloc_page(gfp_flags);
 127                         if (unlikely(!page))
 128                                 goto out_free_pages;
 129
 130                         bio->bi_io_vec[i].bv_page = page;
 131                         bio->bi_vcnt = i+1;
 132                 }
 133         }
 134         /* If not user-requests, copy the page pointers to all bios */
 135         if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
 136                 for (i=0; i<RESYNC_PAGES ; i++)
 137                         for (j=1; j<pi->raid_disks; j++)
 138                                 r1_bio->bios[j]->bi_io_vec[i].bv_page =
 139                                         r1_bio->bios[0]->bi_io_vec[i].bv_page;
 140         }
 141
 142         r1_bio->master_bio = NULL;
 143
 144         return r1_bio;
 145
 146 out_free_pages:
 147         for (j=0 ; j < pi->raid_disks; j++)
 148                 for (i=0; i < r1_bio->bios[j]->bi_vcnt ; i++)
 149                         put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
 150         j = -1;
 151 out_free_bio:
 152         while (++j < pi->raid_disks)
 153                 bio_put(r1_bio->bios[j]);
 154         r1bio_pool_free(r1_bio, data);
 155         return NULL;
 156 }
 157
 158 static void r1buf_pool_free(void *__r1_bio, void *data)
 159 {
 160         struct pool_info *pi = data;
 161         int i,j;
 162         struct r1bio *r1bio = __r1_bio;
 163
 164         for (i = 0; i < RESYNC_PAGES; i++)
 165                 for (j = pi->raid_disks; j-- ;) {
 166                         if (j == 0 ||
 167                             r1bio->bios[j]->bi_io_vec[i].bv_page !=
 168                             r1bio->bios[0]->bi_io_vec[i].bv_page)
 169                                 safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page);
 170                 }
 171         for (i=0 ; i < pi->raid_disks; i++)
 172                 bio_put(r1bio->bios[i]);
 173
 174         r1bio_pool_free(r1bio, data);
 175 }
 176
 177 static void put_all_bios(struct r1conf *conf, struct r1bio *r1_bio)
 178 {
 179         int i;
 180
 181         for (i = 0; i < conf->raid_disks * 2; i++) {
 182                 struct bio **bio = r1_bio->bios + i;
 183                 if (!BIO_SPECIAL(*bio))
 184                         bio_put(*bio);
 185                 *bio = NULL;
 186         }
 187 }
 188
 189 static void free_r1bio(struct r1bio *r1_bio)
 190 {
 191         struct r1conf *conf = r1_bio->mddev->private;
 192
 193         put_all_bios(conf, r1_bio);
 194         mempool_free(r1_bio, conf->r1bio_pool);
 195 }
 196
 197 static void put_buf(struct r1bio *r1_bio)
 198 {
 199         struct r1conf *conf = r1_bio->mddev->private;
 200         int i;
 201
 202         for (i = 0; i < conf->raid_disks * 2; i++) {
 203                 struct bio *bio = r1_bio->bios[i];
 204                 if (bio->bi_end_io)
 205                         rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
 206         }
 207
 208         mempool_free(r1_bio, conf->r1buf_pool);
 209
 210         lower_barrier(conf);
 211 }
 212
 213 static void reschedule_retry(struct r1bio *r1_bio)
 214 {
 215         unsigned long flags;
 216         struct mddev *mddev = r1_bio->mddev;
 217         struct r1conf *conf = mddev->private;
 218
 219         spin_lock_irqsave(&conf->device_lock, flags);
 220         list_add(&r1_bio->retry_list, &conf->retry_list);
 221         conf->nr_queued ++;
 222         spin_unlock_irqrestore(&conf->device_lock, flags);
 223
 224         wake_up(&conf->wait_barrier);
 225         md_wakeup_thread(mddev->thread);
 226 }
 227
 228 /*
 229  * raid_end_bio_io() is called when we have finished servicing a mirrored
 230  * operation and are ready to return a success/failure code to the buffer
 231  * cache layer.
 232  */
 233 static void call_bio_endio(struct r1bio *r1_bio)
 234 {
 235         struct bio *bio = r1_bio->master_bio;
 236         int done;
 237         struct r1conf *conf = r1_bio->mddev->private;
 238
 239         if (bio->bi_phys_segments) {
 240                 unsigned long flags;
 241                 spin_lock_irqsave(&conf->device_lock, flags);
 242                 bio->bi_phys_segments--;
 243                 done = (bio->bi_phys_segments == 0);
 244                 spin_unlock_irqrestore(&conf->device_lock, flags);
 245         } else
 246                 done = 1;
 247
 248         if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
 249                 clear_bit(BIO_UPTODATE, &bio->bi_flags);
 250         if (done) {
 251                 bio_endio(bio, 0);
 252                 /*
 253                  * Wake up any possible resync thread that waits for the device
 254                  * to go idle.
 255                  */
 256                 allow_barrier(conf);
 257         }
 258 }
 259
 260 static void raid_end_bio_io(struct r1bio *r1_bio)
 261 {
 262         struct bio *bio = r1_bio->master_bio;
 263
 264         /* if nobody has done the final endio yet, do it now */
 265         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 266                 pr_debug("raid1: sync end %s on sectors %llu-%llu\n",
 267                          (bio_data_dir(bio) == WRITE) ? "write" : "read",
 268                          (unsigned long long) bio->bi_sector,
 269                          (unsigned long long) bio->bi_sector +
 270                          (bio->bi_size >> 9) - 1);
 271
 272                 call_bio_endio(r1_bio);
 273         }
 274         free_r1bio(r1_bio);
 275 }
 276
 277 /*
 278  * Update disk head position estimator based on IRQ completion info.
 279  */
 280 static inline void update_head_pos(int disk, struct r1bio *r1_bio)
 281 {
 282         struct r1conf *conf = r1_bio->mddev->private;
 283
 284         conf->mirrors[disk].head_position =
 285                 r1_bio->sector + (r1_bio->sectors);
 286 }
 287
 288 /*
 289  * Find the disk number which triggered given bio
 290  */
 291 static int find_bio_disk(struct r1bio *r1_bio, struct bio *bio)
 292 {
 293         int mirror;
 294         struct r1conf *conf = r1_bio->mddev->private;
 295         int raid_disks = conf->raid_disks;
 296
 297         for (mirror = 0; mirror < raid_disks * 2; mirror++)
 298                 if (r1_bio->bios[mirror] == bio)
 299                         break;
 300
 301         BUG_ON(mirror == raid_disks * 2);
 302         update_head_pos(mirror, r1_bio);
 303
 304         return mirror;
 305 }
 306
 307 static void raid1_end_read_request(struct bio *bio, int error)
 308 {
 309         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 310         struct r1bio *r1_bio = bio->bi_private;
 311         int mirror;
 312         struct r1conf *conf = r1_bio->mddev->private;
 313
 314         mirror = r1_bio->read_disk;
 315         /*
 316          * this branch is our 'one mirror IO has finished' event handler:
 317          */
 318         update_head_pos(mirror, r1_bio);
 319
 320         if (uptodate)
 321                 set_bit(R1BIO_Uptodate, &r1_bio->state);
 322         else {
 323                 /* If all other devices have failed, we want to return
 324                  * the error upwards rather than fail the last device.
 325                  * Here we redefine "uptodate" to mean "Don't want to retry"
 326                  */
 327                 unsigned long flags;
 328                 spin_lock_irqsave(&conf->device_lock, flags);
 329                 if (r1_bio->mddev->degraded == conf->raid_disks ||
 330                     (r1_bio->mddev->degraded == conf->raid_disks-1 &&
 331                      !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags)))
 332                         uptodate = 1;
 333                 spin_unlock_irqrestore(&conf->device_lock, flags);
 334         }
 335
 336         if (uptodate) {
 337                 raid_end_bio_io(r1_bio);
 338                 rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
 339         } else {
 340                 /*
 341                  * oops, read error:
 342                  */
 343                 char b[BDEVNAME_SIZE];
 344                 printk_ratelimited(
 345                         KERN_ERR "md/raid1:%s: %s: "
 346                         "rescheduling sector %llu\n",
 347                         mdname(conf->mddev),
 348                         bdevname(conf->mirrors[mirror].rdev->bdev,
 349                                  b),
 350                         (unsigned long long)r1_bio->sector);
 351                 set_bit(R1BIO_ReadError, &r1_bio->state);
 352                 reschedule_retry(r1_bio);
 353                 /* don't drop the reference on read_disk yet */
 354         }
 355 }
 356
 357 static void close_write(struct r1bio *r1_bio)
 358 {
 359         /* it really is the end of this request */
 360         if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
 361                 /* free extra copy of the data pages */
 362                 int i = r1_bio->behind_page_count;
 363                 while (i--)
 364                         safe_put_page(r1_bio->behind_bvecs[i].bv_page);
 365                 kfree(r1_bio->behind_bvecs);
 366                 r1_bio->behind_bvecs = NULL;
 367         }
 368         /* clear the bitmap if all writes complete successfully */
 369         bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
 370                         r1_bio->sectors,
 371                         !test_bit(R1BIO_Degraded, &r1_bio->state),
 372                         test_bit(R1BIO_BehindIO, &r1_bio->state));
 373         md_write_end(r1_bio->mddev);
 374 }
 375
 376 static void r1_bio_write_done(struct r1bio *r1_bio)
 377 {
 378         if (!atomic_dec_and_test(&r1_bio->remaining))
 379                 return;
 380
 381         if (test_bit(R1BIO_WriteError, &r1_bio->state))
 382                 reschedule_retry(r1_bio);
 383         else {
 384                 close_write(r1_bio);
 385                 if (test_bit(R1BIO_MadeGood, &r1_bio->state))
 386                         reschedule_retry(r1_bio);
 387                 else
 388                         raid_end_bio_io(r1_bio);
 389         }
 390 }
 391
 392 static void raid1_end_write_request(struct bio *bio, int error)
 393 {
 394         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 395         struct r1bio *r1_bio = bio->bi_private;
 396         int mirror, behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
 397         struct r1conf *conf = r1_bio->mddev->private;
 398         struct bio *to_put = NULL;
 399
 400         mirror = find_bio_disk(r1_bio, bio);
 401
 402         /*
 403          * 'one mirror IO has finished' event handler:
 404          */
 405         if (!uptodate) {
 406                 set_bit(WriteErrorSeen,
 407                         &conf->mirrors[mirror].rdev->flags);
 408                 if (!test_and_set_bit(WantReplacement,
 409                                       &conf->mirrors[mirror].rdev->flags))
 410                         set_bit(MD_RECOVERY_NEEDED, &
 411                                 conf->mddev->recovery);
 412
 413                 set_bit(R1BIO_WriteError, &r1_bio->state);
 414         } else {
 415                 /*
 416                  * Set R1BIO_Uptodate in our master bio, so that we
 417                  * will return a good error code for to the higher
 418                  * levels even if IO on some other mirrored buffer
 419                  * fails.
 420                  *
 421                  * The 'master' represents the composite IO operation
 422                  * to user-side. So if something waits for IO, then it
 423                  * will wait for the 'master' bio.
 424                  */
 425                 sector_t first_bad;
 426                 int bad_sectors;
 427
 428                 r1_bio->bios[mirror] = NULL;
 429                 to_put = bio;
 430                 set_bit(R1BIO_Uptodate, &r1_bio->state);
 431
 432                 /* Maybe we can clear some bad blocks. */
 433                 if (is_badblock(conf->mirrors[mirror].rdev,
 434                                 r1_bio->sector, r1_bio->sectors,
 435                                 &first_bad, &bad_sectors)) {
 436                         r1_bio->bios[mirror] = IO_MADE_GOOD;
 437                         set_bit(R1BIO_MadeGood, &r1_bio->state);
 438                 }
 439         }
 440
 441         if (behind) {
 442                 if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags))
 443                         atomic_dec(&r1_bio->behind_remaining);
 444
 445                 /*
 446                  * In behind mode, we ACK the master bio once the I/O
 447                  * has safely reached all non-writemostly
 448                  * disks. Setting the Returned bit ensures that this
 449                  * gets done only once -- we don't ever want to return
 450                  * -EIO here, instead we'll wait
 451                  */
 452                 if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
 453                     test_bit(R1BIO_Uptodate, &r1_bio->state)) {
 454                         /* Maybe we can return now */
 455                         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 456                                 struct bio *mbio = r1_bio->master_bio;
 457                                 pr_debug("raid1: behind end write sectors"
 458                                          " %llu-%llu\n",
 459                                          (unsigned long long) mbio->bi_sector,
 460                                          (unsigned long long) mbio->bi_sector +
 461                                          (mbio->bi_size >> 9) - 1);
 462                                 call_bio_endio(r1_bio);
 463                         }
 464                 }
 465         }
 466         if (r1_bio->bios[mirror] == NULL)
 467                 rdev_dec_pending(conf->mirrors[mirror].rdev,
 468                                  conf->mddev);
 469
 470         /*
 471          * Let's see if all mirrored write operations have finished
 472          * already.
 473          */
 474         r1_bio_write_done(r1_bio);
 475
 476         if (to_put)
 477                 bio_put(to_put);
 478 }
 479
 480
 481 /*
 482  * This routine returns the disk from which the requested read should
 483  * be done. There is a per-array 'next expected sequential IO' sector
 484  * number - if this matches on the next IO then we use the last disk.
 485  * There is also a per-disk 'last know head position' sector that is
 486  * maintained from IRQ contexts, both the normal and the resync IO
 487  * completion handlers update this position correctly. If there is no
 488  * perfect sequential match then we pick the disk whose head is closest.
 489  *
 490  * If there are 2 mirrors in the same 2 devices, performance degrades
 491  * because position is mirror, not device based.
 492  *
 493  * The rdev for the device selected will have nr_pending incremented.
 494  */
 495 static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sectors)
 496 {
 497         const sector_t this_sector = r1_bio->sector;
 498         int sectors;
 499         int best_good_sectors;
 500         int best_disk, best_dist_disk, best_pending_disk;
 501         int has_nonrot_disk;
 502         int disk;
 503         sector_t best_dist;
 504         unsigned int min_pending;
 505         struct md_rdev *rdev;
 506         int choose_first;
 507         int choose_next_idle;
 508
 509         rcu_read_lock();
 510         /*
 511          * Check if we can balance. We can balance on the whole
 512          * device if no resync is going on, or below the resync window.
 513          * We take the first readable disk when above the resync window.
 514          */
 515  retry:
 516         sectors = r1_bio->sectors;
 517         best_disk = -1;
 518         best_dist_disk = -1;
 519         best_dist = MaxSector;
 520         best_pending_disk = -1;
 521         min_pending = UINT_MAX;
 522         best_good_sectors = 0;
 523         has_nonrot_disk = 0;
 524         choose_next_idle = 0;
 525
 526         if (conf->mddev->recovery_cp < MaxSector &&
 527             (this_sector + sectors >= conf->next_resync))
 528                 choose_first = 1;
 529         else
 530                 choose_first = 0;
 531
 532         for (disk = 0 ; disk < conf->raid_disks * 2 ; disk++) {
 533                 sector_t dist;
 534                 sector_t first_bad;
 535                 int bad_sectors;
 536                 unsigned int pending;
 537                 bool nonrot;
 538
 539                 rdev = rcu_dereference(conf->mirrors[disk].rdev);
 540                 if (r1_bio->bios[disk] == IO_BLOCKED
 541                     || rdev == NULL
 542                     || test_bit(Unmerged, &rdev->flags)
 543                     || test_bit(Faulty, &rdev->flags))
 544                         continue;
 545                 if (!test_bit(In_sync, &rdev->flags) &&
 546                     rdev->recovery_offset < this_sector + sectors)
 547                         continue;
 548                 if (test_bit(WriteMostly, &rdev->flags)) {
 549                         /* Don't balance among write-mostly, just
 550                          * use the first as a last resort */
 551                         if (best_disk < 0) {
 552                                 if (is_badblock(rdev, this_sector, sectors,
 553                                                 &first_bad, &bad_sectors)) {
 554                                         if (first_bad < this_sector)
 555                                                 /* Cannot use this */
 556                                                 continue;
 557                                         best_good_sectors = first_bad - this_sector;
 558                                 } else
 559                                         best_good_sectors = sectors;
 560                                 best_disk = disk;
 561                         }
 562                         continue;
 563                 }
 564                 /* This is a reasonable device to use.  It might
 565                  * even be best.
 566                  */
 567                 if (is_badblock(rdev, this_sector, sectors,
 568                                 &first_bad, &bad_sectors)) {
 569                         if (best_dist < MaxSector)
 570                                 /* already have a better device */
 571                                 continue;
 572                         if (first_bad <= this_sector) {
 573                                 /* cannot read here. If this is the 'primary'
 574                                  * device, then we must not read beyond
 575                                  * bad_sectors from another device..
 576                                  */
 577                                 bad_sectors -= (this_sector - first_bad);
 578                                 if (choose_first && sectors > bad_sectors)
 579                                         sectors = bad_sectors;
 580                                 if (best_good_sectors > sectors)
 581                                         best_good_sectors = sectors;
 582
 583                         } else {
 584                                 sector_t good_sectors = first_bad - this_sector;
 585                                 if (good_sectors > best_good_sectors) {
 586                                         best_good_sectors = good_sectors;
 587                                         best_disk = disk;
 588                                 }
 589                                 if (choose_first)
 590                                         break;
 591                         }
 592                         continue;
 593                 } else
 594                         best_good_sectors = sectors;
 595
 596                 nonrot = blk_queue_nonrot(bdev_get_queue(rdev->bdev));
 597                 has_nonrot_disk |= nonrot;
 598                 pending = atomic_read(&rdev->nr_pending);
 599                 dist = abs(this_sector - conf->mirrors[disk].head_position);
 600                 if (choose_first) {
 601                         best_disk = disk;
 602                         break;
 603                 }
 604                 /* Don't change to another disk for sequential reads */
 605                 if (conf->mirrors[disk].next_seq_sect == this_sector
 606                     || dist == 0) {
 607                         int opt_iosize = bdev_io_opt(rdev->bdev) >> 9;
 608                         struct raid1_info *mirror = &conf->mirrors[disk];
 609
 610                         best_disk = disk;
 611                         /*
 612                          * If buffered sequential IO size exceeds optimal
 613                          * iosize, check if there is idle disk. If yes, choose
 614                          * the idle disk. read_balance could already choose an
 615                          * idle disk before noticing it's a sequential IO in
 616                          * this disk. This doesn't matter because this disk
 617                          * will idle, next time it will be utilized after the
 618                          * first disk has IO size exceeds optimal iosize. In
 619                          * this way, iosize of the first disk will be optimal
 620                          * iosize at least. iosize of the second disk might be
 621                          * small, but not a big deal since when the second disk
 622                          * starts IO, the first disk is likely still busy.
 623                          */
 624                         if (nonrot && opt_iosize > 0 &&
 625                             mirror->seq_start != MaxSector &&
 626                             mirror->next_seq_sect > opt_iosize &&
 627                             mirror->next_seq_sect - opt_iosize >=
 628                             mirror->seq_start) {
 629                                 choose_next_idle = 1;
 630                                 continue;
 631                         }
 632                         break;
 633                 }
 634                 /* If device is idle, use it */
 635                 if (pending == 0) {
 636                         best_disk = disk;
 637                         break;
 638                 }
 639
 640                 if (choose_next_idle)
 641                         continue;
 642
 643                 if (min_pending > pending) {
 644                         min_pending = pending;
 645                         best_pending_disk = disk;
 646                 }
 647
 648                 if (dist < best_dist) {
 649                         best_dist = dist;
 650                         best_dist_disk = disk;
 651                 }
 652         }
 653
 654         /*
 655          * If all disks are rotational, choose the closest disk. If any disk is
 656          * non-rotational, choose the disk with less pending request even the
 657          * disk is rotational, which might/might not be optimal for raids with
 658          * mixed ratation/non-rotational disks depending on workload.
 659          */
 660         if (best_disk == -1) {
 661                 if (has_nonrot_disk)
 662                         best_disk = best_pending_disk;
 663                 else
 664                         best_disk = best_dist_disk;
 665         }
 666
 667         if (best_disk >= 0) {
 668                 rdev = rcu_dereference(conf->mirrors[best_disk].rdev);
 669                 if (!rdev)
 670                         goto retry;
 671                 atomic_inc(&rdev->nr_pending);
 672                 if (test_bit(Faulty, &rdev->flags)) {
 673                         /* cannot risk returning a device that failed
 674                          * before we inc'ed nr_pending
 675                          */
 676                         rdev_dec_pending(rdev, conf->mddev);
 677                         goto retry;
 678                 }
 679                 sectors = best_good_sectors;
 680
 681                 if (conf->mirrors[best_disk].next_seq_sect != this_sector)
 682                         conf->mirrors[best_disk].seq_start = this_sector;
 683
 684                 conf->mirrors[best_disk].next_seq_sect = this_sector + sectors;
 685         }
 686         rcu_read_unlock();
 687         *max_sectors = sectors;
 688
 689         return best_disk;
 690 }
 691
 692 static int raid1_mergeable_bvec(struct request_queue *q,
 693                                 struct bvec_merge_data *bvm,
 694                                 struct bio_vec *biovec)
 695 {
 696         struct mddev *mddev = q->queuedata;
 697         struct r1conf *conf = mddev->private;
 698         sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
 699         int max = biovec->bv_len;
 700
 701         if (mddev->merge_check_needed) {
 702                 int disk;
 703                 rcu_read_lock();
 704                 for (disk = 0; disk < conf->raid_disks * 2; disk++) {
 705                         struct md_rdev *rdev = rcu_dereference(
 706                                 conf->mirrors[disk].rdev);
 707                         if (rdev && !test_bit(Faulty, &rdev->flags)) {
 708                                 struct request_queue *q =
 709                                         bdev_get_queue(rdev->bdev);
 710                                 if (q->merge_bvec_fn) {
 711                                         bvm->bi_sector = sector +
 712                                                 rdev->data_offset;
 713                                         bvm->bi_bdev = rdev->bdev;
 714                                         max = min(max, q->merge_bvec_fn(
 715                                                           q, bvm, biovec));
 716                                 }
 717                         }
 718                 }
 719                 rcu_read_unlock();
 720         }
 721         return max;
 722
 723 }
 724
 725 int md_raid1_congested(struct mddev *mddev, int bits)
 726 {
 727         struct r1conf *conf = mddev->private;
 728         int i, ret = 0;
 729
 730         if ((bits & (1 << BDI_async_congested)) &&
 731             conf->pending_count >= max_queued_requests)
 732                 return 1;
 733
 734         rcu_read_lock();
 735         for (i = 0; i < conf->raid_disks * 2; i++) {
 736                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
 737                 if (rdev && !test_bit(Faulty, &rdev->flags)) {
 738                         struct request_queue *q = bdev_get_queue(rdev->bdev);
 739
 740                         BUG_ON(!q);
 741
 742                         /* Note the '|| 1' - when read_balance prefers
 743                          * non-congested targets, it can be removed
 744                          */
 745                         if ((bits & (1<<BDI_async_congested)) || 1)
 746                                 ret |= bdi_congested(&q->backing_dev_info, bits);
 747                         else
 748                                 ret &= bdi_congested(&q->backing_dev_info, bits);
 749                 }
 750         }
 751         rcu_read_unlock();
 752         return ret;
 753 }
 754 EXPORT_SYMBOL_GPL(md_raid1_congested);
 755
 756 static int raid1_congested(void *data, int bits)
 757 {
 758         struct mddev *mddev = data;
 759
 760         return mddev_congested(mddev, bits) ||
 761                 md_raid1_congested(mddev, bits);
 762 }
 763
 764 static void flush_pending_writes(struct r1conf *conf)
 765 {
 766         /* Any writes that have been queued but are awaiting
 767          * bitmap updates get flushed here.
 768          */
 769         spin_lock_irq(&conf->device_lock);
 770
 771         if (conf->pending_bio_list.head) {
 772                 struct bio *bio;
 773                 bio = bio_list_get(&conf->pending_bio_list);
 774                 conf->pending_count = 0;
 775                 spin_unlock_irq(&conf->device_lock);
 776                 /* flush any pending bitmap writes to
 777                  * disk before proceeding w/ I/O */
 778                 bitmap_unplug(conf->mddev->bitmap);
 779                 wake_up(&conf->wait_barrier);
 780
 781                 while (bio) { /* submit pending writes */
 782                         struct bio *next = bio->bi_next;
 783                         bio->bi_next = NULL;
 784                         if (unlikely((bio->bi_rw & REQ_DISCARD) &&
 785                             !blk_queue_discard(bdev_get_queue(bio->bi_bdev))))
 786                                 /* Just ignore it */
 787                                 bio_endio(bio, 0);
 788                         else
 789                                 generic_make_request(bio);
 790                         bio = next;
 791                 }
 792         } else
 793                 spin_unlock_irq(&conf->device_lock);
 794 }
 795
 796 /* Barriers....
 797  * Sometimes we need to suspend IO while we do something else,
 798  * either some resync/recovery, or reconfigure the array.
 799  * To do this we raise a 'barrier'.
 800  * The 'barrier' is a counter that can be raised multiple times
 801  * to count how many activities are happening which preclude
 802  * normal IO.
 803  * We can only raise the barrier if there is no pending IO.
 804  * i.e. if nr_pending == 0.
 805  * We choose only to raise the barrier if no-one is waiting for the
 806  * barrier to go down.  This means that as soon as an IO request
 807  * is ready, no other operations which require a barrier will start
 808  * until the IO request has had a chance.
 809  *
 810  * So: regular IO calls 'wait_barrier'.  When that returns there
 811  *    is no backgroup IO happening,  It must arrange to call
 812  *    allow_barrier when it has finished its IO.
 813  * backgroup IO calls must call raise_barrier.  Once that returns
 814  *    there is no normal IO happeing.  It must arrange to call
 815  *    lower_barrier when the particular background IO completes.
 816  */
 817 #define RESYNC_DEPTH 32
 818
 819 static void raise_barrier(struct r1conf *conf)
 820 {
 821         spin_lock_irq(&conf->resync_lock);
 822
 823         /* Wait until no block IO is waiting */
 824         wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
 825                             conf->resync_lock);
 826
 827         /* block any new IO from starting */
 828         conf->barrier++;
 829
 830         /* Now wait for all pending IO to complete */
 831         wait_event_lock_irq(conf->wait_barrier,
 832                             !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
 833                             conf->resync_lock);
 834
 835         spin_unlock_irq(&conf->resync_lock);
 836 }
 837
 838 static void lower_barrier(struct r1conf *conf)
 839 {
 840         unsigned long flags;
 841         BUG_ON(conf->barrier <= 0);
 842         spin_lock_irqsave(&conf->resync_lock, flags);
 843         conf->barrier--;
 844         spin_unlock_irqrestore(&conf->resync_lock, flags);
 845         wake_up(&conf->wait_barrier);
 846 }
 847
 848 static void wait_barrier(struct r1conf *conf)
 849 {
 850         spin_lock_irq(&conf->resync_lock);
 851         if (conf->barrier) {
 852                 conf->nr_waiting++;
 853                 /* Wait for the barrier to drop.
 854                  * However if there are already pending
 855                  * requests (preventing the barrier from
 856                  * rising completely), and the
 857                  * pre-process bio queue isn't empty,
 858                  * then don't wait, as we need to empty
 859                  * that queue to get the nr_pending
 860                  * count down.
 861                  */
 862                 wait_event_lock_irq(conf->wait_barrier,
 863                                     !conf->barrier ||
 864                                     (conf->nr_pending &&
 865                                      current->bio_list &&
 866                                      !bio_list_empty(current->bio_list)),
 867                                     conf->resync_lock);
 868                 conf->nr_waiting--;
 869         }
 870         conf->nr_pending++;
 871         spin_unlock_irq(&conf->resync_lock);
 872 }
 873
 874 static void allow_barrier(struct r1conf *conf)
 875 {
 876         unsigned long flags;
 877         spin_lock_irqsave(&conf->resync_lock, flags);
 878         conf->nr_pending--;
 879         spin_unlock_irqrestore(&conf->resync_lock, flags);
 880         wake_up(&conf->wait_barrier);
 881 }
 882
 883 static void freeze_array(struct r1conf *conf)
 884 {
 885         /* stop syncio and normal IO and wait for everything to
 886          * go quite.
 887          * We increment barrier and nr_waiting, and then
 888          * wait until nr_pending match nr_queued+1
 889          * This is called in the context of one normal IO request
 890          * that has failed. Thus any sync request that might be pending
 891          * will be blocked by nr_pending, and we need to wait for
 892          * pending IO requests to complete or be queued for re-try.
 893          * Thus the number queued (nr_queued) plus this request (1)
 894          * must match the number of pending IOs (nr_pending) before
 895          * we continue.
 896          */
 897         spin_lock_irq(&conf->resync_lock);
 898         conf->barrier++;
 899         conf->nr_waiting++;
 900         wait_event_lock_irq_cmd(conf->wait_barrier,
 901                                 conf->nr_pending == conf->nr_queued+1,
 902                                 conf->resync_lock,
 903                                 flush_pending_writes(conf));
 904         spin_unlock_irq(&conf->resync_lock);
 905 }
 906 static void unfreeze_array(struct r1conf *conf)
 907 {
 908         /* reverse the effect of the freeze */
 909         spin_lock_irq(&conf->resync_lock);
 910         conf->barrier--;
 911         conf->nr_waiting--;
 912         wake_up(&conf->wait_barrier);
 913         spin_unlock_irq(&conf->resync_lock);
 914 }
 915
 916
 917 /* duplicate the data pages for behind I/O
 918  */
 919 static void alloc_behind_pages(struct bio *bio, struct r1bio *r1_bio)
 920 {
 921         int i;
 922         struct bio_vec *bvec;
 923         struct bio_vec *bvecs = kzalloc(bio->bi_vcnt * sizeof(struct bio_vec),
 924                                         GFP_NOIO);
 925         if (unlikely(!bvecs))
 926                 return;
 927
 928         bio_for_each_segment(bvec, bio, i) {
 929                 bvecs[i] = *bvec;
 930                 bvecs[i].bv_page = alloc_page(GFP_NOIO);
 931                 if (unlikely(!bvecs[i].bv_page))
 932                         goto do_sync_io;
 933                 memcpy(kmap(bvecs[i].bv_page) + bvec->bv_offset,
 934                        kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
 935                 kunmap(bvecs[i].bv_page);
 936                 kunmap(bvec->bv_page);
 937         }
 938         r1_bio->behind_bvecs = bvecs;
 939         r1_bio->behind_page_count = bio->bi_vcnt;
 940         set_bit(R1BIO_BehindIO, &r1_bio->state);
 941         return;
 942
 943 do_sync_io:
 944         for (i = 0; i < bio->bi_vcnt; i++)
 945                 if (bvecs[i].bv_page)
 946                         put_page(bvecs[i].bv_page);
 947         kfree(bvecs);
 948         pr_debug("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
 949 }
 950
 951 struct raid1_plug_cb {
 952         struct blk_plug_cb      cb;
 953         struct bio_list         pending;
 954         int                     pending_cnt;
 955 };
 956
 957 static void raid1_unplug(struct blk_plug_cb *cb, bool from_schedule)
 958 {
 959         struct raid1_plug_cb *plug = container_of(cb, struct raid1_plug_cb,
 960                                                   cb);
 961         struct mddev *mddev = plug->cb.data;
 962         struct r1conf *conf = mddev->private;
 963         struct bio *bio;
 964
 965         if (from_schedule || current->bio_list) {
 966                 spin_lock_irq(&conf->device_lock);
 967                 bio_list_merge(&conf->pending_bio_list, &plug->pending);
 968                 conf->pending_count += plug->pending_cnt;
 969                 spin_unlock_irq(&conf->device_lock);
 970                 wake_up(&conf->wait_barrier);
 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                 if (unlikely((bio->bi_rw & REQ_DISCARD) &&
 985                     !blk_queue_discard(bdev_get_queue(bio->bi_bdev))))
 986                         /* Just ignore it */
 987                         bio_endio(bio, 0);
 988                 else
 989                         generic_make_request(bio);
 990                 bio = next;
 991         }
 992         kfree(plug);
 993 }
 994
 995 static void make_request(struct mddev *mddev, struct bio * bio)
 996 {
 997         struct r1conf *conf = mddev->private;
 998         struct raid1_info *mirror;
 999         struct r1bio *r1_bio;
1000         struct bio *read_bio;
1001         int i, disks;
1002         struct bitmap *bitmap;
1003         unsigned long flags;
1004         const int rw = bio_data_dir(bio);
1005         const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
1006         const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA));
1007         const unsigned long do_discard = (bio->bi_rw
1008                                           & (REQ_DISCARD | REQ_SECURE));
1009         const unsigned long do_same = (bio->bi_rw & REQ_WRITE_SAME);
1010         struct md_rdev *blocked_rdev;
1011         struct blk_plug_cb *cb;
1012         struct raid1_plug_cb *plug = NULL;
1013         int first_clone;
1014         int sectors_handled;
1015         int max_sectors;
1016
1017         /*
1018          * Register the new request and wait if the reconstruction
1019          * thread has put up a bar for new requests.
1020          * Continue immediately if no resync is active currently.
1021          */
1022
1023         md_write_start(mddev, bio); /* wait on superblock update early */
1024
1025         if (bio_data_dir(bio) == WRITE &&
1026             bio->bi_sector + bio->bi_size/512 > mddev->suspend_lo &&
1027             bio->bi_sector < mddev->suspend_hi) {
1028                 /* As the suspend_* range is controlled by
1029                  * userspace, we want an interruptible
1030                  * wait.
1031                  */
1032                 DEFINE_WAIT(w);
1033                 for (;;) {
1034                         flush_signals(current);
1035                         prepare_to_wait(&conf->wait_barrier,
1036                                         &w, TASK_INTERRUPTIBLE);
1037                         if (bio->bi_sector + bio->bi_size/512 <= mddev->suspend_lo ||
1038                             bio->bi_sector >= mddev->suspend_hi)
1039                                 break;
1040                         schedule();
1041                 }
1042                 finish_wait(&conf->wait_barrier, &w);
1043         }
1044
1045         wait_barrier(conf);
1046
1047         bitmap = mddev->bitmap;
1048
1049         /*
1050          * make_request() can abort the operation when READA is being
1051          * used and no empty request is available.
1052          *
1053          */
1054         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1055
1056         r1_bio->master_bio = bio;
1057         r1_bio->sectors = bio->bi_size >> 9;
1058         r1_bio->state = 0;
1059         r1_bio->mddev = mddev;
1060         r1_bio->sector = bio->bi_sector;
1061
1062         /* We might need to issue multiple reads to different
1063          * devices if there are bad blocks around, so we keep
1064          * track of the number of reads in bio->bi_phys_segments.
1065          * If this is 0, there is only one r1_bio and no locking
1066          * will be needed when requests complete.  If it is
1067          * non-zero, then it is the number of not-completed requests.
1068          */
1069         bio->bi_phys_segments = 0;
1070         clear_bit(BIO_SEG_VALID, &bio->bi_flags);
1071
1072         if (rw == READ) {
1073                 /*
1074                  * read balancing logic:
1075                  */
1076                 int rdisk;
1077
1078 read_again:
1079                 rdisk = read_balance(conf, r1_bio, &max_sectors);
1080
1081                 if (rdisk < 0) {
1082                         /* couldn't find anywhere to read from */
1083                         raid_end_bio_io(r1_bio);
1084                         return;
1085                 }
1086                 mirror = conf->mirrors + rdisk;
1087
1088                 if (test_bit(WriteMostly, &mirror->rdev->flags) &&
1089                     bitmap) {
1090                         /* Reading from a write-mostly device must
1091                          * take care not to over-take any writes
1092                          * that are 'behind'
1093                          */
1094                         wait_event(bitmap->behind_wait,
1095                                    atomic_read(&bitmap->behind_writes) == 0);
1096                 }
1097                 r1_bio->read_disk = rdisk;
1098
1099                 read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1100                 md_trim_bio(read_bio, r1_bio->sector - bio->bi_sector,
1101                             max_sectors);
1102
1103                 r1_bio->bios[rdisk] = read_bio;
1104
1105                 read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
1106                 read_bio->bi_bdev = mirror->rdev->bdev;
1107                 read_bio->bi_end_io = raid1_end_read_request;
1108                 read_bio->bi_rw = READ | do_sync;
1109                 read_bio->bi_private = r1_bio;
1110
1111                 if (max_sectors < r1_bio->sectors) {
1112                         /* could not read all from this device, so we will
1113                          * need another r1_bio.
1114                          */
1115
1116                         sectors_handled = (r1_bio->sector + max_sectors
1117                                            - bio->bi_sector);
1118                         r1_bio->sectors = max_sectors;
1119                         spin_lock_irq(&conf->device_lock);
1120                         if (bio->bi_phys_segments == 0)
1121                                 bio->bi_phys_segments = 2;
1122                         else
1123                                 bio->bi_phys_segments++;
1124                         spin_unlock_irq(&conf->device_lock);
1125                         /* Cannot call generic_make_request directly
1126                          * as that will be queued in __make_request
1127                          * and subsequent mempool_alloc might block waiting
1128                          * for it.  So hand bio over to raid1d.
1129                          */
1130                         reschedule_retry(r1_bio);
1131
1132                         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1133
1134                         r1_bio->master_bio = bio;
1135                         r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
1136                         r1_bio->state = 0;
1137                         r1_bio->mddev = mddev;
1138                         r1_bio->sector = bio->bi_sector + sectors_handled;
1139                         goto read_again;
1140                 } else
1141                         generic_make_request(read_bio);
1142                 return;
1143         }
1144
1145         /*
1146          * WRITE:
1147          */
1148         if (conf->pending_count >= max_queued_requests) {
1149                 md_wakeup_thread(mddev->thread);
1150                 wait_event(conf->wait_barrier,
1151                            conf->pending_count < max_queued_requests);
1152         }
1153         /* first select target devices under rcu_lock and
1154          * inc refcount on their rdev.  Record them by setting
1155          * bios[x] to bio
1156          * If there are known/acknowledged bad blocks on any device on
1157          * which we have seen a write error, we want to avoid writing those
1158          * blocks.
1159          * This potentially requires several writes to write around
1160          * the bad blocks.  Each set of writes gets it's own r1bio
1161          * with a set of bios attached.
1162          */
1163
1164         disks = conf->raid_disks * 2;
1165  retry_write:
1166         blocked_rdev = NULL;
1167         rcu_read_lock();
1168         max_sectors = r1_bio->sectors;
1169         for (i = 0;  i < disks; i++) {
1170                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1171                 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
1172                         atomic_inc(&rdev->nr_pending);
1173                         blocked_rdev = rdev;
1174                         break;
1175                 }
1176                 r1_bio->bios[i] = NULL;
1177                 if (!rdev || test_bit(Faulty, &rdev->flags)
1178                     || test_bit(Unmerged, &rdev->flags)) {
1179                         if (i < conf->raid_disks)
1180                                 set_bit(R1BIO_Degraded, &r1_bio->state);
1181                         continue;
1182                 }
1183
1184                 atomic_inc(&rdev->nr_pending);
1185                 if (test_bit(WriteErrorSeen, &rdev->flags)) {
1186                         sector_t first_bad;
1187                         int bad_sectors;
1188                         int is_bad;
1189
1190                         is_bad = is_badblock(rdev, r1_bio->sector,
1191                                              max_sectors,
1192                                              &first_bad, &bad_sectors);
1193                         if (is_bad < 0) {
1194                                 /* mustn't write here until the bad block is
1195                                  * acknowledged*/
1196                                 set_bit(BlockedBadBlocks, &rdev->flags);
1197                                 blocked_rdev = rdev;
1198                                 break;
1199                         }
1200                         if (is_bad && first_bad <= r1_bio->sector) {
1201                                 /* Cannot write here at all */
1202                                 bad_sectors -= (r1_bio->sector - first_bad);
1203                                 if (bad_sectors < max_sectors)
1204                                         /* mustn't write more than bad_sectors
1205                                          * to other devices yet
1206                                          */
1207                                         max_sectors = bad_sectors;
1208                                 rdev_dec_pending(rdev, mddev);
1209                                 /* We don't set R1BIO_Degraded as that
1210                                  * only applies if the disk is
1211                                  * missing, so it might be re-added,
1212                                  * and we want to know to recover this
1213                                  * chunk.
1214                                  * In this case the device is here,
1215                                  * and the fact that this chunk is not
1216                                  * in-sync is recorded in the bad
1217                                  * block log
1218                                  */
1219                                 continue;
1220                         }
1221                         if (is_bad) {
1222                                 int good_sectors = first_bad - r1_bio->sector;
1223                                 if (good_sectors < max_sectors)
1224                                         max_sectors = good_sectors;
1225                         }
1226                 }
1227                 r1_bio->bios[i] = bio;
1228         }
1229         rcu_read_unlock();
1230
1231         if (unlikely(blocked_rdev)) {
1232                 /* Wait for this device to become unblocked */
1233                 int j;
1234
1235                 for (j = 0; j < i; j++)
1236                         if (r1_bio->bios[j])
1237                                 rdev_dec_pending(conf->mirrors[j].rdev, mddev);
1238                 r1_bio->state = 0;
1239                 allow_barrier(conf);
1240                 md_wait_for_blocked_rdev(blocked_rdev, mddev);
1241                 wait_barrier(conf);
1242                 goto retry_write;
1243         }
1244
1245         if (max_sectors < r1_bio->sectors) {
1246                 /* We are splitting this write into multiple parts, so
1247                  * we need to prepare for allocating another r1_bio.
1248                  */
1249                 r1_bio->sectors = max_sectors;
1250                 spin_lock_irq(&conf->device_lock);
1251                 if (bio->bi_phys_segments == 0)
1252                         bio->bi_phys_segments = 2;
1253                 else
1254                         bio->bi_phys_segments++;
1255                 spin_unlock_irq(&conf->device_lock);
1256         }
1257         sectors_handled = r1_bio->sector + max_sectors - bio->bi_sector;
1258
1259         atomic_set(&r1_bio->remaining, 1);
1260         atomic_set(&r1_bio->behind_remaining, 0);
1261
1262         first_clone = 1;
1263         for (i = 0; i < disks; i++) {
1264                 struct bio *mbio;
1265                 if (!r1_bio->bios[i])
1266                         continue;
1267
1268                 mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1269                 md_trim_bio(mbio, r1_bio->sector - bio->bi_sector, max_sectors);
1270
1271                 if (first_clone) {
1272                         /* do behind I/O ?
1273                          * Not if there are too many, or cannot
1274                          * allocate memory, or a reader on WriteMostly
1275                          * is waiting for behind writes to flush */
1276                         if (bitmap &&
1277                             (atomic_read(&bitmap->behind_writes)
1278                              < mddev->bitmap_info.max_write_behind) &&
1279                             !waitqueue_active(&bitmap->behind_wait))
1280                                 alloc_behind_pages(mbio, r1_bio);
1281
1282                         bitmap_startwrite(bitmap, r1_bio->sector,
1283                                           r1_bio->sectors,
1284                                           test_bit(R1BIO_BehindIO,
1285                                                    &r1_bio->state));
1286                         first_clone = 0;
1287                 }
1288                 if (r1_bio->behind_bvecs) {
1289                         struct bio_vec *bvec;
1290                         int j;
1291
1292                         /* Yes, I really want the '__' version so that
1293                          * we clear any unused pointer in the io_vec, rather
1294                          * than leave them unchanged.  This is important
1295                          * because when we come to free the pages, we won't
1296                          * know the original bi_idx, so we just free
1297                          * them all
1298                          */
1299                         __bio_for_each_segment(bvec, mbio, j, 0)
1300                                 bvec->bv_page = r1_bio->behind_bvecs[j].bv_page;
1301                         if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
1302                                 atomic_inc(&r1_bio->behind_remaining);
1303                 }
1304
1305                 r1_bio->bios[i] = mbio;
1306
1307                 mbio->bi_sector = (r1_bio->sector +
1308                                    conf->mirrors[i].rdev->data_offset);
1309                 mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1310                 mbio->bi_end_io = raid1_end_write_request;
1311                 mbio->bi_rw =
1312                         WRITE | do_flush_fua | do_sync | do_discard | do_same;
1313                 mbio->bi_private = r1_bio;
1314
1315                 atomic_inc(&r1_bio->remaining);
1316
1317                 cb = blk_check_plugged(raid1_unplug, mddev, sizeof(*plug));
1318                 if (cb)
1319                         plug = container_of(cb, struct raid1_plug_cb, cb);
1320                 else
1321                         plug = NULL;
1322                 spin_lock_irqsave(&conf->device_lock, flags);
1323                 if (plug) {
1324                         bio_list_add(&plug->pending, mbio);
1325                         plug->pending_cnt++;
1326                 } else {
1327                         bio_list_add(&conf->pending_bio_list, mbio);
1328                         conf->pending_count++;
1329                 }
1330                 spin_unlock_irqrestore(&conf->device_lock, flags);
1331                 if (!plug)
1332                         md_wakeup_thread(mddev->thread);
1333         }
1334         /* Mustn't call r1_bio_write_done before this next test,
1335          * as it could result in the bio being freed.
1336          */
1337         if (sectors_handled < (bio->bi_size >> 9)) {
1338                 r1_bio_write_done(r1_bio);
1339                 /* We need another r1_bio.  It has already been counted
1340                  * in bio->bi_phys_segments
1341                  */
1342                 r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1343                 r1_bio->master_bio = bio;
1344                 r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
1345                 r1_bio->state = 0;
1346                 r1_bio->mddev = mddev;
1347                 r1_bio->sector = bio->bi_sector + sectors_handled;
1348                 goto retry_write;
1349         }
1350
1351         r1_bio_write_done(r1_bio);
1352
1353         /* In case raid1d snuck in to freeze_array */
1354         wake_up(&conf->wait_barrier);
1355 }
1356
1357 static void status(struct seq_file *seq, struct mddev *mddev)
1358 {
1359         struct r1conf *conf = mddev->private;
1360         int i;
1361
1362         seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1363                    conf->raid_disks - mddev->degraded);
1364         rcu_read_lock();
1365         for (i = 0; i < conf->raid_disks; i++) {
1366                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1367                 seq_printf(seq, "%s",
1368                            rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1369         }
1370         rcu_read_unlock();
1371         seq_printf(seq, "]");
1372 }
1373
1374
1375 static void error(struct mddev *mddev, struct md_rdev *rdev)
1376 {
1377         char b[BDEVNAME_SIZE];
1378         struct r1conf *conf = mddev->private;
1379
1380         /*
1381          * If it is not operational, then we have already marked it as dead
1382          * else if it is the last working disks, ignore the error, let the
1383          * next level up know.
1384          * else mark the drive as failed
1385          */
1386         if (test_bit(In_sync, &rdev->flags)
1387             && (conf->raid_disks - mddev->degraded) == 1) {
1388                 /*
1389                  * Don't fail the drive, act as though we were just a
1390                  * normal single drive.
1391                  * However don't try a recovery from this drive as
1392                  * it is very likely to fail.
1393                  */
1394                 conf->recovery_disabled = mddev->recovery_disabled;
1395                 return;
1396         }
1397         set_bit(Blocked, &rdev->flags);
1398         if (test_and_clear_bit(In_sync, &rdev->flags)) {
1399                 unsigned long flags;
1400                 spin_lock_irqsave(&conf->device_lock, flags);
1401                 mddev->degraded++;
1402                 set_bit(Faulty, &rdev->flags);
1403                 spin_unlock_irqrestore(&conf->device_lock, flags);
1404                 /*
1405                  * if recovery is running, make sure it aborts.
1406                  */
1407                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1408         } else
1409                 set_bit(Faulty, &rdev->flags);
1410         set_bit(MD_CHANGE_DEVS, &mddev->flags);
1411         printk(KERN_ALERT
1412                "md/raid1:%s: Disk failure on %s, disabling device.\n"
1413                "md/raid1:%s: Operation continuing on %d devices.\n",
1414                mdname(mddev), bdevname(rdev->bdev, b),
1415                mdname(mddev), conf->raid_disks - mddev->degraded);
1416 }
1417
1418 static void print_conf(struct r1conf *conf)
1419 {
1420         int i;
1421
1422         printk(KERN_DEBUG "RAID1 conf printout:\n");
1423         if (!conf) {
1424                 printk(KERN_DEBUG "(!conf)\n");
1425                 return;
1426         }
1427         printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1428                 conf->raid_disks);
1429
1430         rcu_read_lock();
1431         for (i = 0; i < conf->raid_disks; i++) {
1432                 char b[BDEVNAME_SIZE];
1433                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1434                 if (rdev)
1435                         printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
1436                                i, !test_bit(In_sync, &rdev->flags),
1437                                !test_bit(Faulty, &rdev->flags),
1438                                bdevname(rdev->bdev,b));
1439         }
1440         rcu_read_unlock();
1441 }
1442
1443 static void close_sync(struct r1conf *conf)
1444 {
1445         wait_barrier(conf);
1446         allow_barrier(conf);
1447
1448         mempool_destroy(conf->r1buf_pool);
1449         conf->r1buf_pool = NULL;
1450 }
1451
1452 static int raid1_spare_active(struct mddev *mddev)
1453 {
1454         int i;
1455         struct r1conf *conf = mddev->private;
1456         int count = 0;
1457         unsigned long flags;
1458
1459         /*
1460          * Find all failed disks within the RAID1 configuration
1461          * and mark them readable.
1462          * Called under mddev lock, so rcu protection not needed.
1463          */
1464         for (i = 0; i < conf->raid_disks; i++) {
1465                 struct md_rdev *rdev = conf->mirrors[i].rdev;
1466                 struct md_rdev *repl = conf->mirrors[conf->raid_disks + i].rdev;
1467                 if (repl
1468                     && repl->recovery_offset == MaxSector
1469                     && !test_bit(Faulty, &repl->flags)
1470                     && !test_and_set_bit(In_sync, &repl->flags)) {
1471                         /* replacement has just become active */
1472                         if (!rdev ||
1473                             !test_and_clear_bit(In_sync, &rdev->flags))
1474                                 count++;
1475                         if (rdev) {
1476                                 /* Replaced device not technically
1477                                  * faulty, but we need to be sure
1478                                  * it gets removed and never re-added
1479                                  */
1480                                 set_bit(Faulty, &rdev->flags);
1481                                 sysfs_notify_dirent_safe(
1482                                         rdev->sysfs_state);
1483                         }
1484                 }
1485                 if (rdev
1486                     && !test_bit(Faulty, &rdev->flags)
1487                     && !test_and_set_bit(In_sync, &rdev->flags)) {
1488                         count++;
1489                         sysfs_notify_dirent_safe(rdev->sysfs_state);
1490                 }
1491         }
1492         spin_lock_irqsave(&conf->device_lock, flags);
1493         mddev->degraded -= count;
1494         spin_unlock_irqrestore(&conf->device_lock, flags);
1495
1496         print_conf(conf);
1497         return count;
1498 }
1499
1500
1501 static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
1502 {
1503         struct r1conf *conf = mddev->private;
1504         int err = -EEXIST;
1505         int mirror = 0;
1506         struct raid1_info *p;
1507         int first = 0;
1508         int last = conf->raid_disks - 1;
1509         struct request_queue *q = bdev_get_queue(rdev->bdev);
1510
1511         if (mddev->recovery_disabled == conf->recovery_disabled)
1512                 return -EBUSY;
1513
1514         if (rdev->raid_disk >= 0)
1515                 first = last = rdev->raid_disk;
1516
1517         if (q->merge_bvec_fn) {
1518                 set_bit(Unmerged, &rdev->flags);
1519                 mddev->merge_check_needed = 1;
1520         }
1521
1522         for (mirror = first; mirror <= last; mirror++) {
1523                 p = conf->mirrors+mirror;
1524                 if (!p->rdev) {
1525
1526                         disk_stack_limits(mddev->gendisk, rdev->bdev,
1527                                           rdev->data_offset << 9);
1528
1529                         p->head_position = 0;
1530                         rdev->raid_disk = mirror;
1531                         err = 0;
1532                         /* As all devices are equivalent, we don't need a full recovery
1533                          * if this was recently any drive of the array
1534                          */
1535                         if (rdev->saved_raid_disk < 0)
1536                                 conf->fullsync = 1;
1537                         rcu_assign_pointer(p->rdev, rdev);
1538                         break;
1539                 }
1540                 if (test_bit(WantReplacement, &p->rdev->flags) &&
1541                     p[conf->raid_disks].rdev == NULL) {
1542                         /* Add this device as a replacement */
1543                         clear_bit(In_sync, &rdev->flags);
1544                         set_bit(Replacement, &rdev->flags);
1545                         rdev->raid_disk = mirror;
1546                         err = 0;
1547                         conf->fullsync = 1;
1548                         rcu_assign_pointer(p[conf->raid_disks].rdev, rdev);
1549                         break;
1550                 }
1551         }
1552         if (err == 0 && test_bit(Unmerged, &rdev->flags)) {
1553                 /* Some requests might not have seen this new
1554                  * merge_bvec_fn.  We must wait for them to complete
1555                  * before merging the device fully.
1556                  * First we make sure any code which has tested
1557                  * our function has submitted the request, then
1558                  * we wait for all outstanding requests to complete.
1559                  */
1560                 synchronize_sched();
1561                 raise_barrier(conf);
1562                 lower_barrier(conf);
1563                 clear_bit(Unmerged, &rdev->flags);
1564         }
1565         md_integrity_add_rdev(rdev, mddev);
1566         if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
1567                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
1568         print_conf(conf);
1569         return err;
1570 }
1571
1572 static int raid1_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
1573 {
1574         struct r1conf *conf = mddev->private;
1575         int err = 0;
1576         int number = rdev->raid_disk;
1577         struct raid1_info *p = conf->mirrors + number;
1578
1579         if (rdev != p->rdev)
1580                 p = conf->mirrors + conf->raid_disks + number;
1581
1582         print_conf(conf);
1583         if (rdev == p->rdev) {
1584                 if (test_bit(In_sync, &rdev->flags) ||
1585                     atomic_read(&rdev->nr_pending)) {
1586                         err = -EBUSY;
1587                         goto abort;
1588                 }
1589                 /* Only remove non-faulty devices if recovery
1590                  * is not possible.
1591                  */
1592                 if (!test_bit(Faulty, &rdev->flags) &&
1593                     mddev->recovery_disabled != conf->recovery_disabled &&
1594                     mddev->degraded < conf->raid_disks) {
1595                         err = -EBUSY;
1596                         goto abort;
1597                 }
1598                 p->rdev = NULL;
1599                 synchronize_rcu();
1600                 if (atomic_read(&rdev->nr_pending)) {
1601                         /* lost the race, try later */
1602                         err = -EBUSY;
1603                         p->rdev = rdev;
1604                         goto abort;
1605                 } else if (conf->mirrors[conf->raid_disks + number].rdev) {
1606                         /* We just removed a device that is being replaced.
1607                          * Move down the replacement.  We drain all IO before
1608                          * doing this to avoid confusion.
1609                          */
1610                         struct md_rdev *repl =
1611                                 conf->mirrors[conf->raid_disks + number].rdev;
1612                         raise_barrier(conf);
1613                         clear_bit(Replacement, &repl->flags);
1614                         p->rdev = repl;
1615                         conf->mirrors[conf->raid_disks + number].rdev = NULL;
1616                         lower_barrier(conf);
1617                         clear_bit(WantReplacement, &rdev->flags);
1618                 } else
1619                         clear_bit(WantReplacement, &rdev->flags);
1620                 err = md_integrity_register(mddev);
1621         }
1622 abort:
1623
1624         print_conf(conf);
1625         return err;
1626 }
1627
1628
1629 static void end_sync_read(struct bio *bio, int error)
1630 {
1631         struct r1bio *r1_bio = bio->bi_private;
1632
1633         update_head_pos(r1_bio->read_disk, r1_bio);
1634
1635         /*
1636          * we have read a block, now it needs to be re-written,
1637          * or re-read if the read failed.
1638          * We don't do much here, just schedule handling by raid1d
1639          */
1640         if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1641                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1642
1643         if (atomic_dec_and_test(&r1_bio->remaining))
1644                 reschedule_retry(r1_bio);
1645 }
1646
1647 static void end_sync_write(struct bio *bio, int error)
1648 {
1649         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1650         struct r1bio *r1_bio = bio->bi_private;
1651         struct mddev *mddev = r1_bio->mddev;
1652         struct r1conf *conf = mddev->private;
1653         int mirror=0;
1654         sector_t first_bad;
1655         int bad_sectors;
1656
1657         mirror = find_bio_disk(r1_bio, bio);
1658
1659         if (!uptodate) {
1660                 sector_t sync_blocks = 0;
1661                 sector_t s = r1_bio->sector;
1662                 long sectors_to_go = r1_bio->sectors;
1663                 /* make sure these bits doesn't get cleared. */
1664                 do {
1665                         bitmap_end_sync(mddev->bitmap, s,
1666                                         &sync_blocks, 1);
1667                         s += sync_blocks;
1668                         sectors_to_go -= sync_blocks;
1669                 } while (sectors_to_go > 0);
1670                 set_bit(WriteErrorSeen,
1671                         &conf->mirrors[mirror].rdev->flags);
1672                 if (!test_and_set_bit(WantReplacement,
1673                                       &conf->mirrors[mirror].rdev->flags))
1674                         set_bit(MD_RECOVERY_NEEDED, &
1675                                 mddev->recovery);
1676                 set_bit(R1BIO_WriteError, &r1_bio->state);
1677         } else if (is_badblock(conf->mirrors[mirror].rdev,
1678                                r1_bio->sector,
1679                                r1_bio->sectors,
1680                                &first_bad, &bad_sectors) &&
1681                    !is_badblock(conf->mirrors[r1_bio->read_disk].rdev,
1682                                 r1_bio->sector,
1683                                 r1_bio->sectors,
1684                                 &first_bad, &bad_sectors)
1685                 )
1686                 set_bit(R1BIO_MadeGood, &r1_bio->state);
1687
1688         if (atomic_dec_and_test(&r1_bio->remaining)) {
1689                 int s = r1_bio->sectors;
1690                 if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
1691                     test_bit(R1BIO_WriteError, &r1_bio->state))
1692                         reschedule_retry(r1_bio);
1693                 else {
1694                         put_buf(r1_bio);
1695                         md_done_sync(mddev, s, uptodate);
1696                 }
1697         }
1698 }
1699
1700 static int r1_sync_page_io(struct md_rdev *rdev, sector_t sector,
1701                             int sectors, struct page *page, int rw)
1702 {
1703         if (sync_page_io(rdev, sector, sectors << 9, page, rw, false))
1704                 /* success */
1705                 return 1;
1706         if (rw == WRITE) {
1707                 set_bit(WriteErrorSeen, &rdev->flags);
1708                 if (!test_and_set_bit(WantReplacement,
1709                                       &rdev->flags))
1710                         set_bit(MD_RECOVERY_NEEDED, &
1711                                 rdev->mddev->recovery);
1712         }
1713         /* need to record an error - either for the block or the device */
1714         if (!rdev_set_badblocks(rdev, sector, sectors, 0))
1715                 md_error(rdev->mddev, rdev);
1716         return 0;
1717 }
1718
1719 static int fix_sync_read_error(struct r1bio *r1_bio)
1720 {
1721         /* Try some synchronous reads of other devices to get
1722          * good data, much like with normal read errors.  Only
1723          * read into the pages we already have so we don't
1724          * need to re-issue the read request.
1725          * We don't need to freeze the array, because being in an
1726          * active sync request, there is no normal IO, and
1727          * no overlapping syncs.
1728          * We don't need to check is_badblock() again as we
1729          * made sure that anything with a bad block in range
1730          * will have bi_end_io clear.
1731          */
1732         struct mddev *mddev = r1_bio->mddev;
1733         struct r1conf *conf = mddev->private;
1734         struct bio *bio = r1_bio->bios[r1_bio->read_disk];
1735         sector_t sect = r1_bio->sector;
1736         int sectors = r1_bio->sectors;
1737         int idx = 0;
1738
1739         while(sectors) {
1740                 int s = sectors;
1741                 int d = r1_bio->read_disk;
1742                 int success = 0;
1743                 struct md_rdev *rdev;
1744                 int start;
1745
1746                 if (s > (PAGE_SIZE>>9))
1747                         s = PAGE_SIZE >> 9;
1748                 do {
1749                         if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1750                                 /* No rcu protection needed here devices
1751                                  * can only be removed when no resync is
1752                                  * active, and resync is currently active
1753                                  */
1754                                 rdev = conf->mirrors[d].rdev;
1755                                 if (sync_page_io(rdev, sect, s<<9,
1756                                                  bio->bi_io_vec[idx].bv_page,
1757                                                  READ, false)) {
1758                                         success = 1;
1759                                         break;
1760                                 }
1761                         }
1762                         d++;
1763                         if (d == conf->raid_disks * 2)
1764                                 d = 0;
1765                 } while (!success && d != r1_bio->read_disk);
1766
1767                 if (!success) {
1768                         char b[BDEVNAME_SIZE];
1769                         int abort = 0;
1770                         /* Cannot read from anywhere, this block is lost.
1771                          * Record a bad block on each device.  If that doesn't
1772                          * work just disable and interrupt the recovery.
1773                          * Don't fail devices as that won't really help.
1774                          */
1775                         printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O read error"
1776                                " for block %llu\n",
1777                                mdname(mddev),
1778                                bdevname(bio->bi_bdev, b),
1779                                (unsigned long long)r1_bio->sector);
1780                         for (d = 0; d < conf->raid_disks * 2; d++) {
1781                                 rdev = conf->mirrors[d].rdev;
1782                                 if (!rdev || test_bit(Faulty, &rdev->flags))
1783                                         continue;
1784                                 if (!rdev_set_badblocks(rdev, sect, s, 0))
1785                                         abort = 1;
1786                         }
1787                         if (abort) {
1788                                 conf->recovery_disabled =
1789                                         mddev->recovery_disabled;
1790                                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1791                                 md_done_sync(mddev, r1_bio->sectors, 0);
1792                                 put_buf(r1_bio);
1793                                 return 0;
1794                         }
1795                         /* Try next page */
1796                         sectors -= s;
1797                         sect += s;
1798                         idx++;
1799                         continue;
1800                 }
1801
1802                 start = d;
1803                 /* write it back and re-read */
1804                 while (d != r1_bio->read_disk) {
1805                         if (d == 0)
1806                                 d = conf->raid_disks * 2;
1807                         d--;
1808                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1809                                 continue;
1810                         rdev = conf->mirrors[d].rdev;
1811                         if (r1_sync_page_io(rdev, sect, s,
1812                                             bio->bi_io_vec[idx].bv_page,
1813                                             WRITE) == 0) {
1814                                 r1_bio->bios[d]->bi_end_io = NULL;
1815                                 rdev_dec_pending(rdev, mddev);
1816                         }
1817                 }
1818                 d = start;
1819                 while (d != r1_bio->read_disk) {
1820                         if (d == 0)
1821                                 d = conf->raid_disks * 2;
1822                         d--;
1823                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1824                                 continue;
1825                         rdev = conf->mirrors[d].rdev;
1826                         if (r1_sync_page_io(rdev, sect, s,
1827                                             bio->bi_io_vec[idx].bv_page,
1828                                             READ) != 0)
1829                                 atomic_add(s, &rdev->corrected_errors);
1830                 }
1831                 sectors -= s;
1832                 sect += s;
1833                 idx ++;
1834         }
1835         set_bit(R1BIO_Uptodate, &r1_bio->state);
1836         set_bit(BIO_UPTODATE, &bio->bi_flags);
1837         return 1;
1838 }
1839
1840 static int process_checks(struct r1bio *r1_bio)
1841 {
1842         /* We have read all readable devices.  If we haven't
1843          * got the block, then there is no hope left.
1844          * If we have, then we want to do a comparison
1845          * and skip the write if everything is the same.
1846          * If any blocks failed to read, then we need to
1847          * attempt an over-write
1848          */
1849         struct mddev *mddev = r1_bio->mddev;
1850         struct r1conf *conf = mddev->private;
1851         int primary;
1852         int i;
1853         int vcnt;
1854
1855         for (primary = 0; primary < conf->raid_disks * 2; primary++)
1856                 if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1857                     test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
1858                         r1_bio->bios[primary]->bi_end_io = NULL;
1859                         rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1860                         break;
1861                 }
1862         r1_bio->read_disk = primary;
1863         vcnt = (r1_bio->sectors + PAGE_SIZE / 512 - 1) >> (PAGE_SHIFT - 9);
1864         for (i = 0; i < conf->raid_disks * 2; i++) {
1865                 int j;
1866                 struct bio *pbio = r1_bio->bios[primary];
1867                 struct bio *sbio = r1_bio->bios[i];
1868                 int size;
1869
1870                 if (r1_bio->bios[i]->bi_end_io != end_sync_read)
1871                         continue;
1872
1873                 if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
1874                         for (j = vcnt; j-- ; ) {
1875                                 struct page *p, *s;
1876                                 p = pbio->bi_io_vec[j].bv_page;
1877                                 s = sbio->bi_io_vec[j].bv_page;
1878                                 if (memcmp(page_address(p),
1879                                            page_address(s),
1880                                            sbio->bi_io_vec[j].bv_len))
1881                                         break;
1882                         }
1883                 } else
1884                         j = 0;
1885                 if (j >= 0)
1886                         atomic64_add(r1_bio->sectors, &mddev->resync_mismatches);
1887                 if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
1888                               && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
1889                         /* No need to write to this device. */
1890                         sbio->bi_end_io = NULL;
1891                         rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1892                         continue;
1893                 }
1894                 /* fixup the bio for reuse */
1895                 sbio->bi_vcnt = vcnt;
1896                 sbio->bi_size = r1_bio->sectors << 9;
1897                 sbio->bi_idx = 0;
1898                 sbio->bi_phys_segments = 0;
1899                 sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1900                 sbio->bi_flags |= 1 << BIO_UPTODATE;
1901                 sbio->bi_next = NULL;
1902                 sbio->bi_sector = r1_bio->sector +
1903                         conf->mirrors[i].rdev->data_offset;
1904                 sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1905                 size = sbio->bi_size;
1906                 for (j = 0; j < vcnt ; j++) {
1907                         struct bio_vec *bi;
1908                         bi = &sbio->bi_io_vec[j];
1909                         bi->bv_offset = 0;
1910                         if (size > PAGE_SIZE)
1911                                 bi->bv_len = PAGE_SIZE;
1912                         else
1913                                 bi->bv_len = size;
1914                         size -= PAGE_SIZE;
1915                         memcpy(page_address(bi->bv_page),
1916                                page_address(pbio->bi_io_vec[j].bv_page),
1917                                PAGE_SIZE);
1918                 }
1919         }
1920         return 0;
1921 }
1922
1923 static void sync_request_write(struct mddev *mddev, struct r1bio *r1_bio)
1924 {
1925         struct r1conf *conf = mddev->private;
1926         int i;
1927         int disks = conf->raid_disks * 2;
1928         struct bio *bio, *wbio;
1929
1930         bio = r1_bio->bios[r1_bio->read_disk];
1931
1932         if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
1933                 /* ouch - failed to read all of that. */
1934                 if (!fix_sync_read_error(r1_bio))
1935                         return;
1936
1937         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1938                 if (process_checks(r1_bio) < 0)
1939                         return;
1940         /*
1941          * schedule writes
1942          */
1943         atomic_set(&r1_bio->remaining, 1);
1944         for (i = 0; i < disks ; i++) {
1945                 wbio = r1_bio->bios[i];
1946                 if (wbio->bi_end_io == NULL ||
1947                     (wbio->bi_end_io == end_sync_read &&
1948                      (i == r1_bio->read_disk ||
1949                       !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
1950                         continue;
1951
1952                 wbio->bi_rw = WRITE;
1953                 wbio->bi_end_io = end_sync_write;
1954                 atomic_inc(&r1_bio->remaining);
1955                 md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1956
1957                 generic_make_request(wbio);
1958         }
1959
1960         if (atomic_dec_and_test(&r1_bio->remaining)) {
1961                 /* if we're here, all write(s) have completed, so clean up */
1962                 int s = r1_bio->sectors;
1963                 if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
1964                     test_bit(R1BIO_WriteError, &r1_bio->state))
1965                         reschedule_retry(r1_bio);
1966                 else {
1967                         put_buf(r1_bio);
1968                         md_done_sync(mddev, s, 1);
1969                 }
1970         }
1971 }
1972
1973 /*
1974  * This is a kernel thread which:
1975  *
1976  *      1.      Retries failed read operations on working mirrors.
1977  *      2.      Updates the raid superblock when problems encounter.
1978  *      3.      Performs writes following reads for array synchronising.
1979  */
1980
1981 static void fix_read_error(struct r1conf *conf, int read_disk,
1982                            sector_t sect, int sectors)
1983 {
1984         struct mddev *mddev = conf->mddev;
1985         while(sectors) {
1986                 int s = sectors;
1987                 int d = read_disk;
1988                 int success = 0;
1989                 int start;
1990                 struct md_rdev *rdev;
1991
1992                 if (s > (PAGE_SIZE>>9))
1993                         s = PAGE_SIZE >> 9;
1994
1995                 do {
1996                         /* Note: no rcu protection needed here
1997                          * as this is synchronous in the raid1d thread
1998                          * which is the thread that might remove
1999                          * a device.  If raid1d ever becomes multi-threaded....
2000                          */
2001                         sector_t first_bad;
2002                         int bad_sectors;
2003
2004                         rdev = conf->mirrors[d].rdev;
2005                         if (rdev &&
2006                             (test_bit(In_sync, &rdev->flags) ||
2007                              (!test_bit(Faulty, &rdev->flags) &&
2008                               rdev->recovery_offset >= sect + s)) &&
2009                             is_badblock(rdev, sect, s,
2010                                         &first_bad, &bad_sectors) == 0 &&
2011                             sync_page_io(rdev, sect, s<<9,
2012                                          conf->tmppage, READ, false))
2013                                 success = 1;
2014                         else {
2015                                 d++;
2016                                 if (d == conf->raid_disks * 2)
2017                                         d = 0;
2018                         }
2019                 } while (!success && d != read_disk);
2020
2021                 if (!success) {
2022                         /* Cannot read from anywhere - mark it bad */
2023                         struct md_rdev *rdev = conf->mirrors[read_disk].rdev;
2024                         if (!rdev_set_badblocks(rdev, sect, s, 0))
2025                                 md_error(mddev, rdev);
2026                         break;
2027                 }
2028                 /* write it back and re-read */
2029                 start = d;
2030                 while (d != read_disk) {
2031                         if (d==0)
2032                                 d = conf->raid_disks * 2;
2033                         d--;
2034                         rdev = conf->mirrors[d].rdev;
2035                         if (rdev &&
2036                             test_bit(In_sync, &rdev->flags))
2037                                 r1_sync_page_io(rdev, sect, s,
2038                                                 conf->tmppage, WRITE);
2039                 }
2040                 d = start;
2041                 while (d != read_disk) {
2042                         char b[BDEVNAME_SIZE];
2043                         if (d==0)
2044                                 d = conf->raid_disks * 2;
2045                         d--;
2046                         rdev = conf->mirrors[d].rdev;
2047                         if (rdev &&
2048                             test_bit(In_sync, &rdev->flags)) {
2049                                 if (r1_sync_page_io(rdev, sect, s,
2050                                                     conf->tmppage, READ)) {
2051                                         atomic_add(s, &rdev->corrected_errors);
2052                                         printk(KERN_INFO
2053                                                "md/raid1:%s: read error corrected "
2054                                                "(%d sectors at %llu on %s)\n",
2055                                                mdname(mddev), s,
2056                                                (unsigned long long)(sect +
2057                                                    rdev->data_offset),
2058                                                bdevname(rdev->bdev, b));
2059                                 }
2060                         }
2061                 }
2062                 sectors -= s;
2063                 sect += s;
2064         }
2065 }
2066
2067 static void bi_complete(struct bio *bio, int error)
2068 {
2069         complete((struct completion *)bio->bi_private);
2070 }
2071
2072 static int submit_bio_wait(int rw, struct bio *bio)
2073 {
2074         struct completion event;
2075         rw |= REQ_SYNC;
2076
2077         init_completion(&event);
2078         bio->bi_private = &event;
2079         bio->bi_end_io = bi_complete;
2080         submit_bio(rw, bio);
2081         wait_for_completion(&event);
2082
2083         return test_bit(BIO_UPTODATE, &bio->bi_flags);
2084 }
2085
2086 static int narrow_write_error(struct r1bio *r1_bio, int i)
2087 {
2088         struct mddev *mddev = r1_bio->mddev;
2089         struct r1conf *conf = mddev->private;
2090         struct md_rdev *rdev = conf->mirrors[i].rdev;
2091         int vcnt, idx;
2092         struct bio_vec *vec;
2093
2094         /* bio has the data to be written to device 'i' where
2095          * we just recently had a write error.
2096          * We repeatedly clone the bio and trim down to one block,
2097          * then try the write.  Where the write fails we record
2098          * a bad block.
2099          * It is conceivable that the bio doesn't exactly align with
2100          * blocks.  We must handle this somehow.
2101          *
2102          * We currently own a reference on the rdev.
2103          */
2104
2105         int block_sectors;
2106         sector_t sector;
2107         int sectors;
2108         int sect_to_write = r1_bio->sectors;
2109         int ok = 1;
2110
2111         if (rdev->badblocks.shift < 0)
2112                 return 0;
2113
2114         block_sectors = 1 << rdev->badblocks.shift;
2115         sector = r1_bio->sector;
2116         sectors = ((sector + block_sectors)
2117                    & ~(sector_t)(block_sectors - 1))
2118                 - sector;
2119
2120         if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
2121                 vcnt = r1_bio->behind_page_count;
2122                 vec = r1_bio->behind_bvecs;
2123                 idx = 0;
2124                 while (vec[idx].bv_page == NULL)
2125                         idx++;
2126         } else {
2127                 vcnt = r1_bio->master_bio->bi_vcnt;
2128                 vec = r1_bio->master_bio->bi_io_vec;
2129                 idx = r1_bio->master_bio->bi_idx;
2130         }
2131         while (sect_to_write) {
2132                 struct bio *wbio;
2133                 if (sectors > sect_to_write)
2134                         sectors = sect_to_write;
2135                 /* Write at 'sector' for 'sectors'*/
2136
2137                 wbio = bio_alloc_mddev(GFP_NOIO, vcnt, mddev);
2138                 memcpy(wbio->bi_io_vec, vec, vcnt * sizeof(struct bio_vec));
2139                 wbio->bi_sector = r1_bio->sector;
2140                 wbio->bi_rw = WRITE;
2141                 wbio->bi_vcnt = vcnt;
2142                 wbio->bi_size = r1_bio->sectors << 9;
2143                 wbio->bi_idx = idx;
2144
2145                 md_trim_bio(wbio, sector - r1_bio->sector, sectors);
2146                 wbio->bi_sector += rdev->data_offset;
2147                 wbio->bi_bdev = rdev->bdev;
2148                 if (submit_bio_wait(WRITE, wbio) == 0)
2149                         /* failure! */
2150                         ok = rdev_set_badblocks(rdev, sector,
2151                                                 sectors, 0)
2152                                 && ok;
2153
2154                 bio_put(wbio);
2155                 sect_to_write -= sectors;
2156                 sector += sectors;
2157                 sectors = block_sectors;
2158         }
2159         return ok;
2160 }
2161
2162 static void handle_sync_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2163 {
2164         int m;
2165         int s = r1_bio->sectors;
2166         for (m = 0; m < conf->raid_disks * 2 ; m++) {
2167                 struct md_rdev *rdev = conf->mirrors[m].rdev;
2168                 struct bio *bio = r1_bio->bios[m];
2169                 if (bio->bi_end_io == NULL)
2170                         continue;
2171                 if (test_bit(BIO_UPTODATE, &bio->bi_flags) &&
2172                     test_bit(R1BIO_MadeGood, &r1_bio->state)) {
2173                         rdev_clear_badblocks(rdev, r1_bio->sector, s, 0);
2174                 }
2175                 if (!test_bit(BIO_UPTODATE, &bio->bi_flags) &&
2176                     test_bit(R1BIO_WriteError, &r1_bio->state)) {
2177                         if (!rdev_set_badblocks(rdev, r1_bio->sector, s, 0))
2178                                 md_error(conf->mddev, rdev);
2179                 }
2180         }
2181         put_buf(r1_bio);
2182         md_done_sync(conf->mddev, s, 1);
2183 }
2184
2185 static void handle_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2186 {
2187         int m;
2188         for (m = 0; m < conf->raid_disks * 2 ; m++)
2189                 if (r1_bio->bios[m] == IO_MADE_GOOD) {
2190                         struct md_rdev *rdev = conf->mirrors[m].rdev;
2191                         rdev_clear_badblocks(rdev,
2192                                              r1_bio->sector,
2193                                              r1_bio->sectors, 0);
2194                         rdev_dec_pending(rdev, conf->mddev);
2195                 } else if (r1_bio->bios[m] != NULL) {
2196                         /* This drive got a write error.  We need to
2197                          * narrow down and record precise write
2198                          * errors.
2199                          */
2200                         if (!narrow_write_error(r1_bio, m)) {
2201                                 md_error(conf->mddev,
2202                                          conf->mirrors[m].rdev);
2203                                 /* an I/O failed, we can't clear the bitmap */
2204                                 set_bit(R1BIO_Degraded, &r1_bio->state);
2205                         }
2206                         rdev_dec_pending(conf->mirrors[m].rdev,
2207                                          conf->mddev);
2208                 }
2209         if (test_bit(R1BIO_WriteError, &r1_bio->state))
2210                 close_write(r1_bio);
2211         raid_end_bio_io(r1_bio);
2212 }
2213
2214 static void handle_read_error(struct r1conf *conf, struct r1bio *r1_bio)
2215 {
2216         int disk;
2217         int max_sectors;
2218         struct mddev *mddev = conf->mddev;
2219         struct bio *bio;
2220         char b[BDEVNAME_SIZE];
2221         struct md_rdev *rdev;
2222
2223         clear_bit(R1BIO_ReadError, &r1_bio->state);
2224         /* we got a read error. Maybe the drive is bad.  Maybe just
2225          * the block and we can fix it.
2226          * We freeze all other IO, and try reading the block from
2227          * other devices.  When we find one, we re-write
2228          * and check it that fixes the read error.
2229          * This is all done synchronously while the array is
2230          * frozen
2231          */
2232         if (mddev->ro == 0) {
2233                 freeze_array(conf);
2234                 fix_read_error(conf, r1_bio->read_disk,
2235                                r1_bio->sector, r1_bio->sectors);
2236                 unfreeze_array(conf);
2237         } else
2238                 md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
2239         rdev_dec_pending(conf->mirrors[r1_bio->read_disk].rdev, conf->mddev);
2240
2241         bio = r1_bio->bios[r1_bio->read_disk];
2242         bdevname(bio->bi_bdev, b);
2243 read_more:
2244         disk = read_balance(conf, r1_bio, &max_sectors);
2245         if (disk == -1) {
2246                 printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O"
2247                        " read error for block %llu\n",
2248                        mdname(mddev), b, (unsigned long long)r1_bio->sector);
2249                 raid_end_bio_io(r1_bio);
2250         } else {
2251                 const unsigned long do_sync
2252                         = r1_bio->master_bio->bi_rw & REQ_SYNC;
2253                 if (bio) {
2254                         r1_bio->bios[r1_bio->read_disk] =
2255                                 mddev->ro ? IO_BLOCKED : NULL;
2256                         bio_put(bio);
2257                 }
2258                 r1_bio->read_disk = disk;
2259                 bio = bio_clone_mddev(r1_bio->master_bio, GFP_NOIO, mddev);
2260                 md_trim_bio(bio, r1_bio->sector - bio->bi_sector, max_sectors);
2261                 r1_bio->bios[r1_bio->read_disk] = bio;
2262                 rdev = conf->mirrors[disk].rdev;
2263                 printk_ratelimited(KERN_ERR
2264                                    "md/raid1:%s: redirecting sector %llu"
2265                                    " to other mirror: %s\n",
2266                                    mdname(mddev),
2267                                    (unsigned long long)r1_bio->sector,
2268                                    bdevname(rdev->bdev, b));
2269                 bio->bi_sector = r1_bio->sector + rdev->data_offset;
2270                 bio->bi_bdev = rdev->bdev;
2271                 bio->bi_end_io = raid1_end_read_request;
2272                 bio->bi_rw = READ | do_sync;
2273                 bio->bi_private = r1_bio;
2274                 if (max_sectors < r1_bio->sectors) {
2275                         /* Drat - have to split this up more */
2276                         struct bio *mbio = r1_bio->master_bio;
2277                         int sectors_handled = (r1_bio->sector + max_sectors
2278                                                - mbio->bi_sector);
2279                         r1_bio->sectors = max_sectors;
2280                         spin_lock_irq(&conf->device_lock);
2281                         if (mbio->bi_phys_segments == 0)
2282                                 mbio->bi_phys_segments = 2;
2283                         else
2284                                 mbio->bi_phys_segments++;
2285                         spin_unlock_irq(&conf->device_lock);
2286                         generic_make_request(bio);
2287                         bio = NULL;
2288
2289                         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
2290
2291                         r1_bio->master_bio = mbio;
2292                         r1_bio->sectors = (mbio->bi_size >> 9)
2293                                           - sectors_handled;
2294                         r1_bio->state = 0;
2295                         set_bit(R1BIO_ReadError, &r1_bio->state);
2296                         r1_bio->mddev = mddev;
2297                         r1_bio->sector = mbio->bi_sector + sectors_handled;
2298
2299                         goto read_more;
2300                 } else
2301                         generic_make_request(bio);
2302         }
2303 }
2304
2305 static void raid1d(struct md_thread *thread)
2306 {
2307         struct mddev *mddev = thread->mddev;
2308         struct r1bio *r1_bio;
2309         unsigned long flags;
2310         struct r1conf *conf = mddev->private;
2311         struct list_head *head = &conf->retry_list;
2312         struct blk_plug plug;
2313
2314         md_check_recovery(mddev);
2315
2316         blk_start_plug(&plug);
2317         for (;;) {
2318
2319                 flush_pending_writes(conf);
2320
2321                 spin_lock_irqsave(&conf->device_lock, flags);
2322                 if (list_empty(head)) {
2323                         spin_unlock_irqrestore(&conf->device_lock, flags);
2324                         break;
2325                 }
2326                 r1_bio = list_entry(head->prev, struct r1bio, retry_list);
2327                 list_del(head->prev);
2328                 conf->nr_queued--;
2329                 spin_unlock_irqrestore(&conf->device_lock, flags);
2330
2331                 mddev = r1_bio->mddev;
2332                 conf = mddev->private;
2333                 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
2334                         if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2335                             test_bit(R1BIO_WriteError, &r1_bio->state))
2336                                 handle_sync_write_finished(conf, r1_bio);
2337                         else
2338                                 sync_request_write(mddev, r1_bio);
2339                 } else if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2340                            test_bit(R1BIO_WriteError, &r1_bio->state))
2341                         handle_write_finished(conf, r1_bio);
2342                 else if (test_bit(R1BIO_ReadError, &r1_bio->state))
2343                         handle_read_error(conf, r1_bio);
2344                 else
2345                         /* just a partial read to be scheduled from separate
2346                          * context
2347                          */
2348                         generic_make_request(r1_bio->bios[r1_bio->read_disk]);
2349
2350                 cond_resched();
2351                 if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
2352                         md_check_recovery(mddev);
2353         }
2354         blk_finish_plug(&plug);
2355 }
2356
2357
2358 static int init_resync(struct r1conf *conf)
2359 {
2360         int buffs;
2361
2362         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
2363         BUG_ON(conf->r1buf_pool);
2364         conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
2365                                           conf->poolinfo);
2366         if (!conf->r1buf_pool)
2367                 return -ENOMEM;
2368         conf->next_resync = 0;
2369         return 0;
2370 }
2371
2372 /*
2373  * perform a "sync" on one "block"
2374  *
2375  * We need to make sure that no normal I/O request - particularly write
2376  * requests - conflict with active sync requests.
2377  *
2378  * This is achieved by tracking pending requests and a 'barrier' concept
2379  * that can be installed to exclude normal IO requests.
2380  */
2381
2382 static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster)
2383 {
2384         struct r1conf *conf = mddev->private;
2385         struct r1bio *r1_bio;
2386         struct bio *bio;
2387         sector_t max_sector, nr_sectors;
2388         int disk = -1;
2389         int i;
2390         int wonly = -1;
2391         int write_targets = 0, read_targets = 0;
2392         sector_t sync_blocks;
2393         int still_degraded = 0;
2394         int good_sectors = RESYNC_SECTORS;
2395         int min_bad = 0; /* number of sectors that are bad in all devices */
2396
2397         if (!conf->r1buf_pool)
2398                 if (init_resync(conf))
2399                         return 0;
2400
2401         max_sector = mddev->dev_sectors;
2402         if (sector_nr >= max_sector) {
2403                 /* If we aborted, we need to abort the
2404                  * sync on the 'current' bitmap chunk (there will
2405                  * only be one in raid1 resync.
2406                  * We can find the current addess in mddev->curr_resync
2407                  */
2408                 if (mddev->curr_resync < max_sector) /* aborted */
2409                         bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
2410                                                 &sync_blocks, 1);
2411                 else /* completed sync */
2412                         conf->fullsync = 0;
2413
2414                 bitmap_close_sync(mddev->bitmap);
2415                 close_sync(conf);
2416                 return 0;
2417         }
2418
2419         if (mddev->bitmap == NULL &&
2420             mddev->recovery_cp == MaxSector &&
2421             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
2422             conf->fullsync == 0) {
2423                 *skipped = 1;
2424                 return max_sector - sector_nr;
2425         }
2426         /* before building a request, check if we can skip these blocks..
2427          * This call the bitmap_start_sync doesn't actually record anything
2428          */
2429         if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
2430             !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2431                 /* We can skip this block, and probably several more */
2432                 *skipped = 1;
2433                 return sync_blocks;
2434         }
2435         /*
2436          * If there is non-resync activity waiting for a turn,
2437          * and resync is going fast enough,
2438          * then let it though before starting on this new sync request.
2439          */
2440         if (!go_faster && conf->nr_waiting)
2441                 msleep_interruptible(1000);
2442
2443         bitmap_cond_end_sync(mddev->bitmap, sector_nr);
2444         r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
2445         raise_barrier(conf);
2446
2447         conf->next_resync = sector_nr;
2448
2449         rcu_read_lock();
2450         /*
2451          * If we get a correctably read error during resync or recovery,
2452          * we might want to read from a different device.  So we
2453          * flag all drives that could conceivably be read from for READ,
2454          * and any others (which will be non-In_sync devices) for WRITE.
2455          * If a read fails, we try reading from something else for which READ
2456          * is OK.
2457          */
2458
2459         r1_bio->mddev = mddev;
2460         r1_bio->sector = sector_nr;
2461         r1_bio->state = 0;
2462         set_bit(R1BIO_IsSync, &r1_bio->state);
2463
2464         for (i = 0; i < conf->raid_disks * 2; i++) {
2465                 struct md_rdev *rdev;
2466                 bio = r1_bio->bios[i];
2467
2468                 /* take from bio_init */
2469                 bio->bi_next = NULL;
2470                 bio->bi_flags &= ~(BIO_POOL_MASK-1);
2471                 bio->bi_flags |= 1 << BIO_UPTODATE;
2472                 bio->bi_rw = READ;
2473                 bio->bi_vcnt = 0;
2474                 bio->bi_idx = 0;
2475                 bio->bi_phys_segments = 0;
2476                 bio->bi_size = 0;
2477                 bio->bi_end_io = NULL;
2478                 bio->bi_private = NULL;
2479
2480                 rdev = rcu_dereference(conf->mirrors[i].rdev);
2481                 if (rdev == NULL ||
2482                     test_bit(Faulty, &rdev->flags)) {
2483                         if (i < conf->raid_disks)
2484                                 still_degraded = 1;
2485                 } else if (!test_bit(In_sync, &rdev->flags)) {
2486                         bio->bi_rw = WRITE;
2487                         bio->bi_end_io = end_sync_write;
2488                         write_targets ++;
2489                 } else {
2490                         /* may need to read from here */
2491                         sector_t first_bad = MaxSector;
2492                         int bad_sectors;
2493
2494                         if (is_badblock(rdev, sector_nr, good_sectors,
2495                                         &first_bad, &bad_sectors)) {
2496                                 if (first_bad > sector_nr)
2497                                         good_sectors = first_bad - sector_nr;
2498                                 else {
2499                                         bad_sectors -= (sector_nr - first_bad);
2500                                         if (min_bad == 0 ||
2501                                             min_bad > bad_sectors)
2502                                                 min_bad = bad_sectors;
2503                                 }
2504                         }
2505                         if (sector_nr < first_bad) {
2506                                 if (test_bit(WriteMostly, &rdev->flags)) {
2507                                         if (wonly < 0)
2508                                                 wonly = i;
2509                                 } else {
2510                                         if (disk < 0)
2511                                                 disk = i;
2512                                 }
2513                                 bio->bi_rw = READ;
2514                                 bio->bi_end_io = end_sync_read;
2515                                 read_targets++;
2516                         } else if (!test_bit(WriteErrorSeen, &rdev->flags) &&
2517                                 test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
2518                                 !test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) {
2519                                 /*
2520                                  * The device is suitable for reading (InSync),
2521                                  * but has bad block(s) here. Let's try to correct them,
2522                                  * if we are doing resync or repair. Otherwise, leave
2523                                  * this device alone for this sync request.
2524                                  */
2525                                 bio->bi_rw = WRITE;
2526                                 bio->bi_end_io = end_sync_write;
2527                                 write_targets++;
2528                         }
2529                 }
2530                 if (bio->bi_end_io) {
2531                         atomic_inc(&rdev->nr_pending);
2532                         bio->bi_sector = sector_nr + rdev->data_offset;
2533                         bio->bi_bdev = rdev->bdev;
2534                         bio->bi_private = r1_bio;
2535                 }
2536         }
2537         rcu_read_unlock();
2538         if (disk < 0)
2539                 disk = wonly;
2540         r1_bio->read_disk = disk;
2541
2542         if (read_targets == 0 && min_bad > 0) {
2543                 /* These sectors are bad on all InSync devices, so we
2544                  * need to mark them bad on all write targets
2545                  */
2546                 int ok = 1;
2547                 for (i = 0 ; i < conf->raid_disks * 2 ; i++)
2548                         if (r1_bio->bios[i]->bi_end_io == end_sync_write) {
2549                                 struct md_rdev *rdev = conf->mirrors[i].rdev;
2550                                 ok = rdev_set_badblocks(rdev, sector_nr,
2551                                                         min_bad, 0
2552                                         ) && ok;
2553                         }
2554                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
2555                 *skipped = 1;
2556                 put_buf(r1_bio);
2557
2558                 if (!ok) {
2559                         /* Cannot record the badblocks, so need to
2560                          * abort the resync.
2561                          * If there are multiple read targets, could just
2562                          * fail the really bad ones ???
2563                          */
2564                         conf->recovery_disabled = mddev->recovery_disabled;
2565                         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2566                         return 0;
2567                 } else
2568                         return min_bad;
2569
2570         }
2571         if (min_bad > 0 && min_bad < good_sectors) {
2572                 /* only resync enough to reach the next bad->good
2573                  * transition */
2574                 good_sectors = min_bad;
2575         }
2576
2577         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
2578                 /* extra read targets are also write targets */
2579                 write_targets += read_targets-1;
2580
2581         if (write_targets == 0 || read_targets == 0) {
2582                 /* There is nowhere to write, so all non-sync
2583                  * drives must be failed - so we are finished
2584                  */
2585                 sector_t rv;
2586                 if (min_bad > 0)
2587                         max_sector = sector_nr + min_bad;
2588                 rv = max_sector - sector_nr;
2589                 *skipped = 1;
2590                 put_buf(r1_bio);
2591                 return rv;
2592         }
2593
2594         if (max_sector > mddev->resync_max)
2595                 max_sector = mddev->resync_max; /* Don't do IO beyond here */
2596         if (max_sector > sector_nr + good_sectors)
2597                 max_sector = sector_nr + good_sectors;
2598         nr_sectors = 0;
2599         sync_blocks = 0;
2600         do {
2601                 struct page *page;
2602                 int len = PAGE_SIZE;
2603                 if (sector_nr + (len>>9) > max_sector)
2604                         len = (max_sector - sector_nr) << 9;
2605                 if (len == 0)
2606                         break;
2607                 if (sync_blocks == 0) {
2608                         if (!bitmap_start_sync(mddev->bitmap, sector_nr,
2609                                                &sync_blocks, still_degraded) &&
2610                             !conf->fullsync &&
2611                             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2612                                 break;
2613                         BUG_ON(sync_blocks < (PAGE_SIZE>>9));
2614                         if ((len >> 9) > sync_blocks)
2615                                 len = sync_blocks<<9;
2616                 }
2617
2618                 for (i = 0 ; i < conf->raid_disks * 2; i++) {
2619                         bio = r1_bio->bios[i];
2620                         if (bio->bi_end_io) {
2621                                 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
2622                                 if (bio_add_page(bio, page, len, 0) == 0) {
2623                                         /* stop here */
2624                                         bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
2625                                         while (i > 0) {
2626                                                 i--;
2627                                                 bio = r1_bio->bios[i];
2628                                                 if (bio->bi_end_io==NULL)
2629                                                         continue;
2630                                                 /* remove last page from this bio */
2631                                                 bio->bi_vcnt--;
2632                                                 bio->bi_size -= len;
2633                                                 bio->bi_flags &= ~(1<< BIO_SEG_VALID);
2634                                         }
2635                                         goto bio_full;
2636                                 }
2637                         }
2638                 }
2639                 nr_sectors += len>>9;
2640                 sector_nr += len>>9;
2641                 sync_blocks -= (len>>9);
2642         } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
2643  bio_full:
2644         r1_bio->sectors = nr_sectors;
2645
2646         /* For a user-requested sync, we read all readable devices and do a
2647          * compare
2648          */
2649         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2650                 atomic_set(&r1_bio->remaining, read_targets);
2651                 for (i = 0; i < conf->raid_disks * 2 && read_targets; i++) {
2652                         bio = r1_bio->bios[i];
2653                         if (bio->bi_end_io == end_sync_read) {
2654                                 read_targets--;
2655                                 md_sync_acct(bio->bi_bdev, nr_sectors);
2656                                 generic_make_request(bio);
2657                         }
2658                 }
2659         } else {
2660                 atomic_set(&r1_bio->remaining, 1);
2661                 bio = r1_bio->bios[r1_bio->read_disk];
2662                 md_sync_acct(bio->bi_bdev, nr_sectors);
2663                 generic_make_request(bio);
2664
2665         }
2666         return nr_sectors;
2667 }
2668
2669 static sector_t raid1_size(struct mddev *mddev, sector_t sectors, int raid_disks)
2670 {
2671         if (sectors)
2672                 return sectors;
2673
2674         return mddev->dev_sectors;
2675 }
2676
2677 static struct r1conf *setup_conf(struct mddev *mddev)
2678 {
2679         struct r1conf *conf;
2680         int i;
2681         struct raid1_info *disk;
2682         struct md_rdev *rdev;
2683         int err = -ENOMEM;
2684
2685         conf = kzalloc(sizeof(struct r1conf), GFP_KERNEL);
2686         if (!conf)
2687                 goto abort;
2688
2689         conf->mirrors = kzalloc(sizeof(struct raid1_info)
2690                                 * mddev->raid_disks * 2,
2691                                  GFP_KERNEL);
2692         if (!conf->mirrors)
2693                 goto abort;
2694
2695         conf->tmppage = alloc_page(GFP_KERNEL);
2696         if (!conf->tmppage)
2697                 goto abort;
2698
2699         conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
2700         if (!conf->poolinfo)
2701                 goto abort;
2702         conf->poolinfo->raid_disks = mddev->raid_disks * 2;
2703         conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2704                                           r1bio_pool_free,
2705                                           conf->poolinfo);
2706         if (!conf->r1bio_pool)
2707                 goto abort;
2708
2709         conf->poolinfo->mddev = mddev;
2710
2711         err = -EINVAL;
2712         spin_lock_init(&conf->device_lock);
2713         rdev_for_each(rdev, mddev) {
2714                 struct request_queue *q;
2715                 int disk_idx = rdev->raid_disk;
2716                 if (disk_idx >= mddev->raid_disks
2717                     || disk_idx < 0)
2718                         continue;
2719                 if (test_bit(Replacement, &rdev->flags))
2720                         disk = conf->mirrors + mddev->raid_disks + disk_idx;
2721                 else
2722                         disk = conf->mirrors + disk_idx;
2723
2724                 if (disk->rdev)
2725                         goto abort;
2726                 disk->rdev = rdev;
2727                 q = bdev_get_queue(rdev->bdev);
2728                 if (q->merge_bvec_fn)
2729                         mddev->merge_check_needed = 1;
2730
2731                 disk->head_position = 0;
2732                 disk->seq_start = MaxSector;
2733         }
2734         conf->raid_disks = mddev->raid_disks;
2735         conf->mddev = mddev;
2736         INIT_LIST_HEAD(&conf->retry_list);
2737
2738         spin_lock_init(&conf->resync_lock);
2739         init_waitqueue_head(&conf->wait_barrier);
2740
2741         bio_list_init(&conf->pending_bio_list);
2742         conf->pending_count = 0;
2743         conf->recovery_disabled = mddev->recovery_disabled - 1;
2744
2745         err = -EIO;
2746         for (i = 0; i < conf->raid_disks * 2; i++) {
2747
2748                 disk = conf->mirrors + i;
2749
2750                 if (i < conf->raid_disks &&
2751                     disk[conf->raid_disks].rdev) {
2752                         /* This slot has a replacement. */
2753                         if (!disk->rdev) {
2754                                 /* No original, just make the replacement
2755                                  * a recovering spare
2756                                  */
2757                                 disk->rdev =
2758                                         disk[conf->raid_disks].rdev;
2759                                 disk[conf->raid_disks].rdev = NULL;
2760                         } else if (!test_bit(In_sync, &disk->rdev->flags))
2761                                 /* Original is not in_sync - bad */
2762                                 goto abort;
2763                 }
2764
2765                 if (!disk->rdev ||
2766                     !test_bit(In_sync, &disk->rdev->flags)) {
2767                         disk->head_position = 0;
2768                         if (disk->rdev &&
2769                             (disk->rdev->saved_raid_disk < 0))
2770                                 conf->fullsync = 1;
2771                 }
2772         }
2773
2774         err = -ENOMEM;
2775         conf->thread = md_register_thread(raid1d, mddev, "raid1");
2776         if (!conf->thread) {
2777                 printk(KERN_ERR
2778                        "md/raid1:%s: couldn't allocate thread\n",
2779                        mdname(mddev));
2780                 goto abort;
2781         }
2782
2783         return conf;
2784
2785  abort:
2786         if (conf) {
2787                 if (conf->r1bio_pool)
2788                         mempool_destroy(conf->r1bio_pool);
2789                 kfree(conf->mirrors);
2790                 safe_put_page(conf->tmppage);
2791                 kfree(conf->poolinfo);
2792                 kfree(conf);
2793         }
2794         return ERR_PTR(err);
2795 }
2796
2797 static int stop(struct mddev *mddev);
2798 static int run(struct mddev *mddev)
2799 {
2800         struct r1conf *conf;
2801         int i;
2802         struct md_rdev *rdev;
2803         int ret;
2804         bool discard_supported = false;
2805
2806         if (mddev->level != 1) {
2807                 printk(KERN_ERR "md/raid1:%s: raid level not set to mirroring (%d)\n",
2808                        mdname(mddev), mddev->level);
2809                 return -EIO;
2810         }
2811         if (mddev->reshape_position != MaxSector) {
2812                 printk(KERN_ERR "md/raid1:%s: reshape_position set but not supported\n",
2813                        mdname(mddev));
2814                 return -EIO;
2815         }
2816         /*
2817          * copy the already verified devices into our private RAID1
2818          * bookkeeping area. [whatever we allocate in run(),
2819          * should be freed in stop()]
2820          */
2821         if (mddev->private == NULL)
2822                 conf = setup_conf(mddev);
2823         else
2824                 conf = mddev->private;
2825
2826         if (IS_ERR(conf))
2827                 return PTR_ERR(conf);
2828
2829         if (mddev->queue)
2830                 blk_queue_max_write_same_sectors(mddev->queue,
2831                                                  mddev->chunk_sectors);
2832         rdev_for_each(rdev, mddev) {
2833                 if (!mddev->gendisk)
2834                         continue;
2835                 disk_stack_limits(mddev->gendisk, rdev->bdev,
2836                                   rdev->data_offset << 9);
2837                 if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
2838                         discard_supported = true;
2839         }
2840
2841         mddev->degraded = 0;
2842         for (i=0; i < conf->raid_disks; i++)
2843                 if (conf->mirrors[i].rdev == NULL ||
2844                     !test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
2845                     test_bit(Faulty, &conf->mirrors[i].rdev->flags))
2846                         mddev->degraded++;
2847
2848         if (conf->raid_disks - mddev->degraded == 1)
2849                 mddev->recovery_cp = MaxSector;
2850
2851         if (mddev->recovery_cp != MaxSector)
2852                 printk(KERN_NOTICE "md/raid1:%s: not clean"
2853                        " -- starting background reconstruction\n",
2854                        mdname(mddev));
2855         printk(KERN_INFO
2856                 "md/raid1:%s: active with %d out of %d mirrors\n",
2857                 mdname(mddev), mddev->raid_disks - mddev->degraded,
2858                 mddev->raid_disks);
2859
2860         /*
2861          * Ok, everything is just fine now
2862          */
2863         mddev->thread = conf->thread;
2864         conf->thread = NULL;
2865         mddev->private = conf;
2866
2867         md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
2868
2869         if (mddev->queue) {
2870                 mddev->queue->backing_dev_info.congested_fn = raid1_congested;
2871                 mddev->queue->backing_dev_info.congested_data = mddev;
2872                 blk_queue_merge_bvec(mddev->queue, raid1_mergeable_bvec);
2873
2874                 if (discard_supported)
2875                         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
2876                                                 mddev->queue);
2877                 else
2878                         queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
2879                                                   mddev->queue);
2880         }
2881
2882         ret =  md_integrity_register(mddev);
2883         if (ret)
2884                 stop(mddev);
2885         return ret;
2886 }
2887
2888 static int stop(struct mddev *mddev)
2889 {
2890         struct r1conf *conf = mddev->private;
2891         struct bitmap *bitmap = mddev->bitmap;
2892
2893         /* wait for behind writes to complete */
2894         if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
2895                 printk(KERN_INFO "md/raid1:%s: behind writes in progress - waiting to stop.\n",
2896                        mdname(mddev));
2897                 /* need to kick something here to make sure I/O goes? */
2898                 wait_event(bitmap->behind_wait,
2899                            atomic_read(&bitmap->behind_writes) == 0);
2900         }
2901
2902         raise_barrier(conf);
2903         lower_barrier(conf);
2904
2905         md_unregister_thread(&mddev->thread);
2906         if (conf->r1bio_pool)
2907                 mempool_destroy(conf->r1bio_pool);
2908         kfree(conf->mirrors);
2909         safe_put_page(conf->tmppage);
2910         kfree(conf->poolinfo);
2911         kfree(conf);
2912         mddev->private = NULL;
2913         return 0;
2914 }
2915
2916 static int raid1_resize(struct mddev *mddev, sector_t sectors)
2917 {
2918         /* no resync is happening, and there is enough space
2919          * on all devices, so we can resize.
2920          * We need to make sure resync covers any new space.
2921          * If the array is shrinking we should possibly wait until
2922          * any io in the removed space completes, but it hardly seems
2923          * worth it.
2924          */
2925         sector_t newsize = raid1_size(mddev, sectors, 0);
2926         if (mddev->external_size &&
2927             mddev->array_sectors > newsize)
2928                 return -EINVAL;
2929         if (mddev->bitmap) {
2930                 int ret = bitmap_resize(mddev->bitmap, newsize, 0, 0);
2931                 if (ret)
2932                         return ret;
2933         }
2934         md_set_array_sectors(mddev, newsize);
2935         set_capacity(mddev->gendisk, mddev->array_sectors);
2936         revalidate_disk(mddev->gendisk);
2937         if (sectors > mddev->dev_sectors &&
2938             mddev->recovery_cp > mddev->dev_sectors) {
2939                 mddev->recovery_cp = mddev->dev_sectors;
2940                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2941         }
2942         mddev->dev_sectors = sectors;
2943         mddev->resync_max_sectors = sectors;
2944         return 0;
2945 }
2946
2947 static int raid1_reshape(struct mddev *mddev)
2948 {
2949         /* We need to:
2950          * 1/ resize the r1bio_pool
2951          * 2/ resize conf->mirrors
2952          *
2953          * We allocate a new r1bio_pool if we can.
2954          * Then raise a device barrier and wait until all IO stops.
2955          * Then resize conf->mirrors and swap in the new r1bio pool.
2956          *
2957          * At the same time, we "pack" the devices so that all the missing
2958          * devices have the higher raid_disk numbers.
2959          */
2960         mempool_t *newpool, *oldpool;
2961         struct pool_info *newpoolinfo;
2962         struct raid1_info *newmirrors;
2963         struct r1conf *conf = mddev->private;
2964         int cnt, raid_disks;
2965         unsigned long flags;
2966         int d, d2, err;
2967
2968         /* Cannot change chunk_size, layout, or level */
2969         if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
2970             mddev->layout != mddev->new_layout ||
2971             mddev->level != mddev->new_level) {
2972                 mddev->new_chunk_sectors = mddev->chunk_sectors;
2973                 mddev->new_layout = mddev->layout;
2974                 mddev->new_level = mddev->level;
2975                 return -EINVAL;
2976         }
2977
2978         err = md_allow_write(mddev);
2979         if (err)
2980                 return err;
2981
2982         raid_disks = mddev->raid_disks + mddev->delta_disks;
2983
2984         if (raid_disks < conf->raid_disks) {
2985                 cnt=0;
2986                 for (d= 0; d < conf->raid_disks; d++)
2987                         if (conf->mirrors[d].rdev)
2988                                 cnt++;
2989                 if (cnt > raid_disks)
2990                         return -EBUSY;
2991         }
2992
2993         newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
2994         if (!newpoolinfo)
2995                 return -ENOMEM;
2996         newpoolinfo->mddev = mddev;
2997         newpoolinfo->raid_disks = raid_disks * 2;
2998
2999         newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
3000                                  r1bio_pool_free, newpoolinfo);
3001         if (!newpool) {
3002                 kfree(newpoolinfo);
3003                 return -ENOMEM;
3004         }
3005         newmirrors = kzalloc(sizeof(struct raid1_info) * raid_disks * 2,
3006                              GFP_KERNEL);
3007         if (!newmirrors) {
3008                 kfree(newpoolinfo);
3009                 mempool_destroy(newpool);
3010                 return -ENOMEM;
3011         }
3012
3013         raise_barrier(conf);
3014
3015         /* ok, everything is stopped */
3016         oldpool = conf->r1bio_pool;
3017         conf->r1bio_pool = newpool;
3018
3019         for (d = d2 = 0; d < conf->raid_disks; d++) {
3020                 struct md_rdev *rdev = conf->mirrors[d].rdev;
3021                 if (rdev && rdev->raid_disk != d2) {
3022                         sysfs_unlink_rdev(mddev, rdev);
3023                         rdev->raid_disk = d2;
3024                         sysfs_unlink_rdev(mddev, rdev);
3025                         if (sysfs_link_rdev(mddev, rdev))
3026                                 printk(KERN_WARNING
3027                                        "md/raid1:%s: cannot register rd%d\n",
3028                                        mdname(mddev), rdev->raid_disk);
3029                 }
3030                 if (rdev)
3031                         newmirrors[d2++].rdev = rdev;
3032         }
3033         kfree(conf->mirrors);
3034         conf->mirrors = newmirrors;
3035         kfree(conf->poolinfo);
3036         conf->poolinfo = newpoolinfo;
3037
3038         spin_lock_irqsave(&conf->device_lock, flags);
3039         mddev->degraded += (raid_disks - conf->raid_disks);
3040         spin_unlock_irqrestore(&conf->device_lock, flags);
3041         conf->raid_disks = mddev->raid_disks = raid_disks;
3042         mddev->delta_disks = 0;
3043
3044         lower_barrier(conf);
3045
3046         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3047         md_wakeup_thread(mddev->thread);
3048
3049         mempool_destroy(oldpool);
3050         return 0;
3051 }
3052
3053 static void raid1_quiesce(struct mddev *mddev, int state)
3054 {
3055         struct r1conf *conf = mddev->private;
3056
3057         switch(state) {
3058         case 2: /* wake for suspend */
3059                 wake_up(&conf->wait_barrier);
3060                 break;
3061         case 1:
3062                 raise_barrier(conf);
3063                 break;
3064         case 0:
3065                 lower_barrier(conf);
3066                 break;
3067         }
3068 }
3069
3070 static void *raid1_takeover(struct mddev *mddev)
3071 {
3072         /* raid1 can take over:
3073          *  raid5 with 2 devices, any layout or chunk size
3074          */
3075         if (mddev->level == 5 && mddev->raid_disks == 2) {
3076                 struct r1conf *conf;
3077                 mddev->new_level = 1;
3078                 mddev->new_layout = 0;
3079                 mddev->new_chunk_sectors = 0;
3080                 conf = setup_conf(mddev);
3081                 if (!IS_ERR(conf))
3082                         conf->barrier = 1;
3083                 return conf;
3084         }
3085         return ERR_PTR(-EINVAL);
3086 }
3087
3088 static struct md_personality raid1_personality =
3089 {
3090         .name           = "raid1",
3091         .level          = 1,
3092         .owner          = THIS_MODULE,
3093         .make_request   = make_request,
3094         .run            = run,
3095         .stop           = stop,
3096         .status         = status,
3097         .error_handler  = error,
3098         .hot_add_disk   = raid1_add_disk,
3099         .hot_remove_disk= raid1_remove_disk,
3100         .spare_active   = raid1_spare_active,
3101         .sync_request   = sync_request,
3102         .resize         = raid1_resize,
3103         .size           = raid1_size,
3104         .check_reshape  = raid1_reshape,
3105         .quiesce        = raid1_quiesce,
3106         .takeover       = raid1_takeover,
3107 };
3108
3109 static int __init raid_init(void)
3110 {
3111         return register_md_personality(&raid1_personality);
3112 }
3113
3114 static void raid_exit(void)
3115 {
3116         unregister_md_personality(&raid1_personality);
3117 }
3118
3119 module_init(raid_init);
3120 module_exit(raid_exit);
3121 MODULE_LICENSE("GPL");
3122 MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
3123 MODULE_ALIAS("md-personality-3"); /* RAID1 */
3124 MODULE_ALIAS("md-raid1");
3125 MODULE_ALIAS("md-level-1");
3126
3127 module_param(max_queued_requests, int, S_IRUGO|S_IWUSR);