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                 generic_make_request(bio);
 985                 bio = next;
 986         }
 987         kfree(plug);
 988 }
 989
 990 static void make_request(struct mddev *mddev, struct bio * bio)
 991 {
 992         struct r1conf *conf = mddev->private;
 993         struct raid1_info *mirror;
 994         struct r1bio *r1_bio;
 995         struct bio *read_bio;
 996         int i, disks;
 997         struct bitmap *bitmap;
 998         unsigned long flags;
 999         const int rw = bio_data_dir(bio);
1000         const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
1001         const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA));
1002         const unsigned long do_discard = (bio->bi_rw
1003                                           & (REQ_DISCARD | REQ_SECURE));
1004         const unsigned long do_same = (bio->bi_rw & REQ_WRITE_SAME);
1005         struct md_rdev *blocked_rdev;
1006         struct blk_plug_cb *cb;
1007         struct raid1_plug_cb *plug = NULL;
1008         int first_clone;
1009         int sectors_handled;
1010         int max_sectors;
1011
1012         /*
1013          * Register the new request and wait if the reconstruction
1014          * thread has put up a bar for new requests.
1015          * Continue immediately if no resync is active currently.
1016          */
1017
1018         md_write_start(mddev, bio); /* wait on superblock update early */
1019
1020         if (bio_data_dir(bio) == WRITE &&
1021             bio->bi_sector + bio->bi_size/512 > mddev->suspend_lo &&
1022             bio->bi_sector < mddev->suspend_hi) {
1023                 /* As the suspend_* range is controlled by
1024                  * userspace, we want an interruptible
1025                  * wait.
1026                  */
1027                 DEFINE_WAIT(w);
1028                 for (;;) {
1029                         flush_signals(current);
1030                         prepare_to_wait(&conf->wait_barrier,
1031                                         &w, TASK_INTERRUPTIBLE);
1032                         if (bio->bi_sector + bio->bi_size/512 <= mddev->suspend_lo ||
1033                             bio->bi_sector >= mddev->suspend_hi)
1034                                 break;
1035                         schedule();
1036                 }
1037                 finish_wait(&conf->wait_barrier, &w);
1038         }
1039
1040         wait_barrier(conf);
1041
1042         bitmap = mddev->bitmap;
1043
1044         /*
1045          * make_request() can abort the operation when READA is being
1046          * used and no empty request is available.
1047          *
1048          */
1049         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1050
1051         r1_bio->master_bio = bio;
1052         r1_bio->sectors = bio->bi_size >> 9;
1053         r1_bio->state = 0;
1054         r1_bio->mddev = mddev;
1055         r1_bio->sector = bio->bi_sector;
1056
1057         /* We might need to issue multiple reads to different
1058          * devices if there are bad blocks around, so we keep
1059          * track of the number of reads in bio->bi_phys_segments.
1060          * If this is 0, there is only one r1_bio and no locking
1061          * will be needed when requests complete.  If it is
1062          * non-zero, then it is the number of not-completed requests.
1063          */
1064         bio->bi_phys_segments = 0;
1065         clear_bit(BIO_SEG_VALID, &bio->bi_flags);
1066
1067         if (rw == READ) {
1068                 /*
1069                  * read balancing logic:
1070                  */
1071                 int rdisk;
1072
1073 read_again:
1074                 rdisk = read_balance(conf, r1_bio, &max_sectors);
1075
1076                 if (rdisk < 0) {
1077                         /* couldn't find anywhere to read from */
1078                         raid_end_bio_io(r1_bio);
1079                         return;
1080                 }
1081                 mirror = conf->mirrors + rdisk;
1082
1083                 if (test_bit(WriteMostly, &mirror->rdev->flags) &&
1084                     bitmap) {
1085                         /* Reading from a write-mostly device must
1086                          * take care not to over-take any writes
1087                          * that are 'behind'
1088                          */
1089                         wait_event(bitmap->behind_wait,
1090                                    atomic_read(&bitmap->behind_writes) == 0);
1091                 }
1092                 r1_bio->read_disk = rdisk;
1093
1094                 read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1095                 md_trim_bio(read_bio, r1_bio->sector - bio->bi_sector,
1096                             max_sectors);
1097
1098                 r1_bio->bios[rdisk] = read_bio;
1099
1100                 read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
1101                 read_bio->bi_bdev = mirror->rdev->bdev;
1102                 read_bio->bi_end_io = raid1_end_read_request;
1103                 read_bio->bi_rw = READ | do_sync;
1104                 read_bio->bi_private = r1_bio;
1105
1106                 if (max_sectors < r1_bio->sectors) {
1107                         /* could not read all from this device, so we will
1108                          * need another r1_bio.
1109                          */
1110
1111                         sectors_handled = (r1_bio->sector + max_sectors
1112                                            - bio->bi_sector);
1113                         r1_bio->sectors = max_sectors;
1114                         spin_lock_irq(&conf->device_lock);
1115                         if (bio->bi_phys_segments == 0)
1116                                 bio->bi_phys_segments = 2;
1117                         else
1118                                 bio->bi_phys_segments++;
1119                         spin_unlock_irq(&conf->device_lock);
1120                         /* Cannot call generic_make_request directly
1121                          * as that will be queued in __make_request
1122                          * and subsequent mempool_alloc might block waiting
1123                          * for it.  So hand bio over to raid1d.
1124                          */
1125                         reschedule_retry(r1_bio);
1126
1127                         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1128
1129                         r1_bio->master_bio = bio;
1130                         r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
1131                         r1_bio->state = 0;
1132                         r1_bio->mddev = mddev;
1133                         r1_bio->sector = bio->bi_sector + sectors_handled;
1134                         goto read_again;
1135                 } else
1136                         generic_make_request(read_bio);
1137                 return;
1138         }
1139
1140         /*
1141          * WRITE:
1142          */
1143         if (conf->pending_count >= max_queued_requests) {
1144                 md_wakeup_thread(mddev->thread);
1145                 wait_event(conf->wait_barrier,
1146                            conf->pending_count < max_queued_requests);
1147         }
1148         /* first select target devices under rcu_lock and
1149          * inc refcount on their rdev.  Record them by setting
1150          * bios[x] to bio
1151          * If there are known/acknowledged bad blocks on any device on
1152          * which we have seen a write error, we want to avoid writing those
1153          * blocks.
1154          * This potentially requires several writes to write around
1155          * the bad blocks.  Each set of writes gets it's own r1bio
1156          * with a set of bios attached.
1157          */
1158
1159         disks = conf->raid_disks * 2;
1160  retry_write:
1161         blocked_rdev = NULL;
1162         rcu_read_lock();
1163         max_sectors = r1_bio->sectors;
1164         for (i = 0;  i < disks; i++) {
1165                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1166                 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
1167                         atomic_inc(&rdev->nr_pending);
1168                         blocked_rdev = rdev;
1169                         break;
1170                 }
1171                 r1_bio->bios[i] = NULL;
1172                 if (!rdev || test_bit(Faulty, &rdev->flags)
1173                     || test_bit(Unmerged, &rdev->flags)) {
1174                         if (i < conf->raid_disks)
1175                                 set_bit(R1BIO_Degraded, &r1_bio->state);
1176                         continue;
1177                 }
1178
1179                 atomic_inc(&rdev->nr_pending);
1180                 if (test_bit(WriteErrorSeen, &rdev->flags)) {
1181                         sector_t first_bad;
1182                         int bad_sectors;
1183                         int is_bad;
1184
1185                         is_bad = is_badblock(rdev, r1_bio->sector,
1186                                              max_sectors,
1187                                              &first_bad, &bad_sectors);
1188                         if (is_bad < 0) {
1189                                 /* mustn't write here until the bad block is
1190                                  * acknowledged*/
1191                                 set_bit(BlockedBadBlocks, &rdev->flags);
1192                                 blocked_rdev = rdev;
1193                                 break;
1194                         }
1195                         if (is_bad && first_bad <= r1_bio->sector) {
1196                                 /* Cannot write here at all */
1197                                 bad_sectors -= (r1_bio->sector - first_bad);
1198                                 if (bad_sectors < max_sectors)
1199                                         /* mustn't write more than bad_sectors
1200                                          * to other devices yet
1201                                          */
1202                                         max_sectors = bad_sectors;
1203                                 rdev_dec_pending(rdev, mddev);
1204                                 /* We don't set R1BIO_Degraded as that
1205                                  * only applies if the disk is
1206                                  * missing, so it might be re-added,
1207                                  * and we want to know to recover this
1208                                  * chunk.
1209                                  * In this case the device is here,
1210                                  * and the fact that this chunk is not
1211                                  * in-sync is recorded in the bad
1212                                  * block log
1213                                  */
1214                                 continue;
1215                         }
1216                         if (is_bad) {
1217                                 int good_sectors = first_bad - r1_bio->sector;
1218                                 if (good_sectors < max_sectors)
1219                                         max_sectors = good_sectors;
1220                         }
1221                 }
1222                 r1_bio->bios[i] = bio;
1223         }
1224         rcu_read_unlock();
1225
1226         if (unlikely(blocked_rdev)) {
1227                 /* Wait for this device to become unblocked */
1228                 int j;
1229
1230                 for (j = 0; j < i; j++)
1231                         if (r1_bio->bios[j])
1232                                 rdev_dec_pending(conf->mirrors[j].rdev, mddev);
1233                 r1_bio->state = 0;
1234                 allow_barrier(conf);
1235                 md_wait_for_blocked_rdev(blocked_rdev, mddev);
1236                 wait_barrier(conf);
1237                 goto retry_write;
1238         }
1239
1240         if (max_sectors < r1_bio->sectors) {
1241                 /* We are splitting this write into multiple parts, so
1242                  * we need to prepare for allocating another r1_bio.
1243                  */
1244                 r1_bio->sectors = max_sectors;
1245                 spin_lock_irq(&conf->device_lock);
1246                 if (bio->bi_phys_segments == 0)
1247                         bio->bi_phys_segments = 2;
1248                 else
1249                         bio->bi_phys_segments++;
1250                 spin_unlock_irq(&conf->device_lock);
1251         }
1252         sectors_handled = r1_bio->sector + max_sectors - bio->bi_sector;
1253
1254         atomic_set(&r1_bio->remaining, 1);
1255         atomic_set(&r1_bio->behind_remaining, 0);
1256
1257         first_clone = 1;
1258         for (i = 0; i < disks; i++) {
1259                 struct bio *mbio;
1260                 if (!r1_bio->bios[i])
1261                         continue;
1262
1263                 mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1264                 md_trim_bio(mbio, r1_bio->sector - bio->bi_sector, max_sectors);
1265
1266                 if (first_clone) {
1267                         /* do behind I/O ?
1268                          * Not if there are too many, or cannot
1269                          * allocate memory, or a reader on WriteMostly
1270                          * is waiting for behind writes to flush */
1271                         if (bitmap &&
1272                             (atomic_read(&bitmap->behind_writes)
1273                              < mddev->bitmap_info.max_write_behind) &&
1274                             !waitqueue_active(&bitmap->behind_wait))
1275                                 alloc_behind_pages(mbio, r1_bio);
1276
1277                         bitmap_startwrite(bitmap, r1_bio->sector,
1278                                           r1_bio->sectors,
1279                                           test_bit(R1BIO_BehindIO,
1280                                                    &r1_bio->state));
1281                         first_clone = 0;
1282                 }
1283                 if (r1_bio->behind_bvecs) {
1284                         struct bio_vec *bvec;
1285                         int j;
1286
1287                         /* Yes, I really want the '__' version so that
1288                          * we clear any unused pointer in the io_vec, rather
1289                          * than leave them unchanged.  This is important
1290                          * because when we come to free the pages, we won't
1291                          * know the original bi_idx, so we just free
1292                          * them all
1293                          */
1294                         __bio_for_each_segment(bvec, mbio, j, 0)
1295                                 bvec->bv_page = r1_bio->behind_bvecs[j].bv_page;
1296                         if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
1297                                 atomic_inc(&r1_bio->behind_remaining);
1298                 }
1299
1300                 r1_bio->bios[i] = mbio;
1301
1302                 mbio->bi_sector = (r1_bio->sector +
1303                                    conf->mirrors[i].rdev->data_offset);
1304                 mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1305                 mbio->bi_end_io = raid1_end_write_request;
1306                 mbio->bi_rw =
1307                         WRITE | do_flush_fua | do_sync | do_discard | do_same;
1308                 mbio->bi_private = r1_bio;
1309
1310                 atomic_inc(&r1_bio->remaining);
1311
1312                 cb = blk_check_plugged(raid1_unplug, mddev, sizeof(*plug));
1313                 if (cb)
1314                         plug = container_of(cb, struct raid1_plug_cb, cb);
1315                 else
1316                         plug = NULL;
1317                 spin_lock_irqsave(&conf->device_lock, flags);
1318                 if (plug) {
1319                         bio_list_add(&plug->pending, mbio);
1320                         plug->pending_cnt++;
1321                 } else {
1322                         bio_list_add(&conf->pending_bio_list, mbio);
1323                         conf->pending_count++;
1324                 }
1325                 spin_unlock_irqrestore(&conf->device_lock, flags);
1326                 if (!plug)
1327                         md_wakeup_thread(mddev->thread);
1328         }
1329         /* Mustn't call r1_bio_write_done before this next test,
1330          * as it could result in the bio being freed.
1331          */
1332         if (sectors_handled < (bio->bi_size >> 9)) {
1333                 r1_bio_write_done(r1_bio);
1334                 /* We need another r1_bio.  It has already been counted
1335                  * in bio->bi_phys_segments
1336                  */
1337                 r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1338                 r1_bio->master_bio = bio;
1339                 r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
1340                 r1_bio->state = 0;
1341                 r1_bio->mddev = mddev;
1342                 r1_bio->sector = bio->bi_sector + sectors_handled;
1343                 goto retry_write;
1344         }
1345
1346         r1_bio_write_done(r1_bio);
1347
1348         /* In case raid1d snuck in to freeze_array */
1349         wake_up(&conf->wait_barrier);
1350 }
1351
1352 static void status(struct seq_file *seq, struct mddev *mddev)
1353 {
1354         struct r1conf *conf = mddev->private;
1355         int i;
1356
1357         seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1358                    conf->raid_disks - mddev->degraded);
1359         rcu_read_lock();
1360         for (i = 0; i < conf->raid_disks; i++) {
1361                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1362                 seq_printf(seq, "%s",
1363                            rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1364         }
1365         rcu_read_unlock();
1366         seq_printf(seq, "]");
1367 }
1368
1369
1370 static void error(struct mddev *mddev, struct md_rdev *rdev)
1371 {
1372         char b[BDEVNAME_SIZE];
1373         struct r1conf *conf = mddev->private;
1374
1375         /*
1376          * If it is not operational, then we have already marked it as dead
1377          * else if it is the last working disks, ignore the error, let the
1378          * next level up know.
1379          * else mark the drive as failed
1380          */
1381         if (test_bit(In_sync, &rdev->flags)
1382             && (conf->raid_disks - mddev->degraded) == 1) {
1383                 /*
1384                  * Don't fail the drive, act as though we were just a
1385                  * normal single drive.
1386                  * However don't try a recovery from this drive as
1387                  * it is very likely to fail.
1388                  */
1389                 conf->recovery_disabled = mddev->recovery_disabled;
1390                 return;
1391         }
1392         set_bit(Blocked, &rdev->flags);
1393         if (test_and_clear_bit(In_sync, &rdev->flags)) {
1394                 unsigned long flags;
1395                 spin_lock_irqsave(&conf->device_lock, flags);
1396                 mddev->degraded++;
1397                 set_bit(Faulty, &rdev->flags);
1398                 spin_unlock_irqrestore(&conf->device_lock, flags);
1399                 /*
1400                  * if recovery is running, make sure it aborts.
1401                  */
1402                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1403         } else
1404                 set_bit(Faulty, &rdev->flags);
1405         set_bit(MD_CHANGE_DEVS, &mddev->flags);
1406         printk(KERN_ALERT
1407                "md/raid1:%s: Disk failure on %s, disabling device.\n"
1408                "md/raid1:%s: Operation continuing on %d devices.\n",
1409                mdname(mddev), bdevname(rdev->bdev, b),
1410                mdname(mddev), conf->raid_disks - mddev->degraded);
1411 }
1412
1413 static void print_conf(struct r1conf *conf)
1414 {
1415         int i;
1416
1417         printk(KERN_DEBUG "RAID1 conf printout:\n");
1418         if (!conf) {
1419                 printk(KERN_DEBUG "(!conf)\n");
1420                 return;
1421         }
1422         printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1423                 conf->raid_disks);
1424
1425         rcu_read_lock();
1426         for (i = 0; i < conf->raid_disks; i++) {
1427                 char b[BDEVNAME_SIZE];
1428                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1429                 if (rdev)
1430                         printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
1431                                i, !test_bit(In_sync, &rdev->flags),
1432                                !test_bit(Faulty, &rdev->flags),
1433                                bdevname(rdev->bdev,b));
1434         }
1435         rcu_read_unlock();
1436 }
1437
1438 static void close_sync(struct r1conf *conf)
1439 {
1440         wait_barrier(conf);
1441         allow_barrier(conf);
1442
1443         mempool_destroy(conf->r1buf_pool);
1444         conf->r1buf_pool = NULL;
1445 }
1446
1447 static int raid1_spare_active(struct mddev *mddev)
1448 {
1449         int i;
1450         struct r1conf *conf = mddev->private;
1451         int count = 0;
1452         unsigned long flags;
1453
1454         /*
1455          * Find all failed disks within the RAID1 configuration
1456          * and mark them readable.
1457          * Called under mddev lock, so rcu protection not needed.
1458          */
1459         for (i = 0; i < conf->raid_disks; i++) {
1460                 struct md_rdev *rdev = conf->mirrors[i].rdev;
1461                 struct md_rdev *repl = conf->mirrors[conf->raid_disks + i].rdev;
1462                 if (repl
1463                     && repl->recovery_offset == MaxSector
1464                     && !test_bit(Faulty, &repl->flags)
1465                     && !test_and_set_bit(In_sync, &repl->flags)) {
1466                         /* replacement has just become active */
1467                         if (!rdev ||
1468                             !test_and_clear_bit(In_sync, &rdev->flags))
1469                                 count++;
1470                         if (rdev) {
1471                                 /* Replaced device not technically
1472                                  * faulty, but we need to be sure
1473                                  * it gets removed and never re-added
1474                                  */
1475                                 set_bit(Faulty, &rdev->flags);
1476                                 sysfs_notify_dirent_safe(
1477                                         rdev->sysfs_state);
1478                         }
1479                 }
1480                 if (rdev
1481                     && !test_bit(Faulty, &rdev->flags)
1482                     && !test_and_set_bit(In_sync, &rdev->flags)) {
1483                         count++;
1484                         sysfs_notify_dirent_safe(rdev->sysfs_state);
1485                 }
1486         }
1487         spin_lock_irqsave(&conf->device_lock, flags);
1488         mddev->degraded -= count;
1489         spin_unlock_irqrestore(&conf->device_lock, flags);
1490
1491         print_conf(conf);
1492         return count;
1493 }
1494
1495
1496 static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
1497 {
1498         struct r1conf *conf = mddev->private;
1499         int err = -EEXIST;
1500         int mirror = 0;
1501         struct raid1_info *p;
1502         int first = 0;
1503         int last = conf->raid_disks - 1;
1504         struct request_queue *q = bdev_get_queue(rdev->bdev);
1505
1506         if (mddev->recovery_disabled == conf->recovery_disabled)
1507                 return -EBUSY;
1508
1509         if (rdev->raid_disk >= 0)
1510                 first = last = rdev->raid_disk;
1511
1512         if (q->merge_bvec_fn) {
1513                 set_bit(Unmerged, &rdev->flags);
1514                 mddev->merge_check_needed = 1;
1515         }
1516
1517         for (mirror = first; mirror <= last; mirror++) {
1518                 p = conf->mirrors+mirror;
1519                 if (!p->rdev) {
1520
1521                         disk_stack_limits(mddev->gendisk, rdev->bdev,
1522                                           rdev->data_offset << 9);
1523
1524                         p->head_position = 0;
1525                         rdev->raid_disk = mirror;
1526                         err = 0;
1527                         /* As all devices are equivalent, we don't need a full recovery
1528                          * if this was recently any drive of the array
1529                          */
1530                         if (rdev->saved_raid_disk < 0)
1531                                 conf->fullsync = 1;
1532                         rcu_assign_pointer(p->rdev, rdev);
1533                         break;
1534                 }
1535                 if (test_bit(WantReplacement, &p->rdev->flags) &&
1536                     p[conf->raid_disks].rdev == NULL) {
1537                         /* Add this device as a replacement */
1538                         clear_bit(In_sync, &rdev->flags);
1539                         set_bit(Replacement, &rdev->flags);
1540                         rdev->raid_disk = mirror;
1541                         err = 0;
1542                         conf->fullsync = 1;
1543                         rcu_assign_pointer(p[conf->raid_disks].rdev, rdev);
1544                         break;
1545                 }
1546         }
1547         if (err == 0 && test_bit(Unmerged, &rdev->flags)) {
1548                 /* Some requests might not have seen this new
1549                  * merge_bvec_fn.  We must wait for them to complete
1550                  * before merging the device fully.
1551                  * First we make sure any code which has tested
1552                  * our function has submitted the request, then
1553                  * we wait for all outstanding requests to complete.
1554                  */
1555                 synchronize_sched();
1556                 raise_barrier(conf);
1557                 lower_barrier(conf);
1558                 clear_bit(Unmerged, &rdev->flags);
1559         }
1560         md_integrity_add_rdev(rdev, mddev);
1561         if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
1562                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
1563         print_conf(conf);
1564         return err;
1565 }
1566
1567 static int raid1_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
1568 {
1569         struct r1conf *conf = mddev->private;
1570         int err = 0;
1571         int number = rdev->raid_disk;
1572         struct raid1_info *p = conf->mirrors + number;
1573
1574         if (rdev != p->rdev)
1575                 p = conf->mirrors + conf->raid_disks + number;
1576
1577         print_conf(conf);
1578         if (rdev == p->rdev) {
1579                 if (test_bit(In_sync, &rdev->flags) ||
1580                     atomic_read(&rdev->nr_pending)) {
1581                         err = -EBUSY;
1582                         goto abort;
1583                 }
1584                 /* Only remove non-faulty devices if recovery
1585                  * is not possible.
1586                  */
1587                 if (!test_bit(Faulty, &rdev->flags) &&
1588                     mddev->recovery_disabled != conf->recovery_disabled &&
1589                     mddev->degraded < conf->raid_disks) {
1590                         err = -EBUSY;
1591                         goto abort;
1592                 }
1593                 p->rdev = NULL;
1594                 synchronize_rcu();
1595                 if (atomic_read(&rdev->nr_pending)) {
1596                         /* lost the race, try later */
1597                         err = -EBUSY;
1598                         p->rdev = rdev;
1599                         goto abort;
1600                 } else if (conf->mirrors[conf->raid_disks + number].rdev) {
1601                         /* We just removed a device that is being replaced.
1602                          * Move down the replacement.  We drain all IO before
1603                          * doing this to avoid confusion.
1604                          */
1605                         struct md_rdev *repl =
1606                                 conf->mirrors[conf->raid_disks + number].rdev;
1607                         raise_barrier(conf);
1608                         clear_bit(Replacement, &repl->flags);
1609                         p->rdev = repl;
1610                         conf->mirrors[conf->raid_disks + number].rdev = NULL;
1611                         lower_barrier(conf);
1612                         clear_bit(WantReplacement, &rdev->flags);
1613                 } else
1614                         clear_bit(WantReplacement, &rdev->flags);
1615                 err = md_integrity_register(mddev);
1616         }
1617 abort:
1618
1619         print_conf(conf);
1620         return err;
1621 }
1622
1623
1624 static void end_sync_read(struct bio *bio, int error)
1625 {
1626         struct r1bio *r1_bio = bio->bi_private;
1627
1628         update_head_pos(r1_bio->read_disk, r1_bio);
1629
1630         /*
1631          * we have read a block, now it needs to be re-written,
1632          * or re-read if the read failed.
1633          * We don't do much here, just schedule handling by raid1d
1634          */
1635         if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1636                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1637
1638         if (atomic_dec_and_test(&r1_bio->remaining))
1639                 reschedule_retry(r1_bio);
1640 }
1641
1642 static void end_sync_write(struct bio *bio, int error)
1643 {
1644         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1645         struct r1bio *r1_bio = bio->bi_private;
1646         struct mddev *mddev = r1_bio->mddev;
1647         struct r1conf *conf = mddev->private;
1648         int mirror=0;
1649         sector_t first_bad;
1650         int bad_sectors;
1651
1652         mirror = find_bio_disk(r1_bio, bio);
1653
1654         if (!uptodate) {
1655                 sector_t sync_blocks = 0;
1656                 sector_t s = r1_bio->sector;
1657                 long sectors_to_go = r1_bio->sectors;
1658                 /* make sure these bits doesn't get cleared. */
1659                 do {
1660                         bitmap_end_sync(mddev->bitmap, s,
1661                                         &sync_blocks, 1);
1662                         s += sync_blocks;
1663                         sectors_to_go -= sync_blocks;
1664                 } while (sectors_to_go > 0);
1665                 set_bit(WriteErrorSeen,
1666                         &conf->mirrors[mirror].rdev->flags);
1667                 if (!test_and_set_bit(WantReplacement,
1668                                       &conf->mirrors[mirror].rdev->flags))
1669                         set_bit(MD_RECOVERY_NEEDED, &
1670                                 mddev->recovery);
1671                 set_bit(R1BIO_WriteError, &r1_bio->state);
1672         } else if (is_badblock(conf->mirrors[mirror].rdev,
1673                                r1_bio->sector,
1674                                r1_bio->sectors,
1675                                &first_bad, &bad_sectors) &&
1676                    !is_badblock(conf->mirrors[r1_bio->read_disk].rdev,
1677                                 r1_bio->sector,
1678                                 r1_bio->sectors,
1679                                 &first_bad, &bad_sectors)
1680                 )
1681                 set_bit(R1BIO_MadeGood, &r1_bio->state);
1682
1683         if (atomic_dec_and_test(&r1_bio->remaining)) {
1684                 int s = r1_bio->sectors;
1685                 if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
1686                     test_bit(R1BIO_WriteError, &r1_bio->state))
1687                         reschedule_retry(r1_bio);
1688                 else {
1689                         put_buf(r1_bio);
1690                         md_done_sync(mddev, s, uptodate);
1691                 }
1692         }
1693 }
1694
1695 static int r1_sync_page_io(struct md_rdev *rdev, sector_t sector,
1696                             int sectors, struct page *page, int rw)
1697 {
1698         if (sync_page_io(rdev, sector, sectors << 9, page, rw, false))
1699                 /* success */
1700                 return 1;
1701         if (rw == WRITE) {
1702                 set_bit(WriteErrorSeen, &rdev->flags);
1703                 if (!test_and_set_bit(WantReplacement,
1704                                       &rdev->flags))
1705                         set_bit(MD_RECOVERY_NEEDED, &
1706                                 rdev->mddev->recovery);
1707         }
1708         /* need to record an error - either for the block or the device */
1709         if (!rdev_set_badblocks(rdev, sector, sectors, 0))
1710                 md_error(rdev->mddev, rdev);
1711         return 0;
1712 }
1713
1714 static int fix_sync_read_error(struct r1bio *r1_bio)
1715 {
1716         /* Try some synchronous reads of other devices to get
1717          * good data, much like with normal read errors.  Only
1718          * read into the pages we already have so we don't
1719          * need to re-issue the read request.
1720          * We don't need to freeze the array, because being in an
1721          * active sync request, there is no normal IO, and
1722          * no overlapping syncs.
1723          * We don't need to check is_badblock() again as we
1724          * made sure that anything with a bad block in range
1725          * will have bi_end_io clear.
1726          */
1727         struct mddev *mddev = r1_bio->mddev;
1728         struct r1conf *conf = mddev->private;
1729         struct bio *bio = r1_bio->bios[r1_bio->read_disk];
1730         sector_t sect = r1_bio->sector;
1731         int sectors = r1_bio->sectors;
1732         int idx = 0;
1733
1734         while(sectors) {
1735                 int s = sectors;
1736                 int d = r1_bio->read_disk;
1737                 int success = 0;
1738                 struct md_rdev *rdev;
1739                 int start;
1740
1741                 if (s > (PAGE_SIZE>>9))
1742                         s = PAGE_SIZE >> 9;
1743                 do {
1744                         if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1745                                 /* No rcu protection needed here devices
1746                                  * can only be removed when no resync is
1747                                  * active, and resync is currently active
1748                                  */
1749                                 rdev = conf->mirrors[d].rdev;
1750                                 if (sync_page_io(rdev, sect, s<<9,
1751                                                  bio->bi_io_vec[idx].bv_page,
1752                                                  READ, false)) {
1753                                         success = 1;
1754                                         break;
1755                                 }
1756                         }
1757                         d++;
1758                         if (d == conf->raid_disks * 2)
1759                                 d = 0;
1760                 } while (!success && d != r1_bio->read_disk);
1761
1762                 if (!success) {
1763                         char b[BDEVNAME_SIZE];
1764                         int abort = 0;
1765                         /* Cannot read from anywhere, this block is lost.
1766                          * Record a bad block on each device.  If that doesn't
1767                          * work just disable and interrupt the recovery.
1768                          * Don't fail devices as that won't really help.
1769                          */
1770                         printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O read error"
1771                                " for block %llu\n",
1772                                mdname(mddev),
1773                                bdevname(bio->bi_bdev, b),
1774                                (unsigned long long)r1_bio->sector);
1775                         for (d = 0; d < conf->raid_disks * 2; d++) {
1776                                 rdev = conf->mirrors[d].rdev;
1777                                 if (!rdev || test_bit(Faulty, &rdev->flags))
1778                                         continue;
1779                                 if (!rdev_set_badblocks(rdev, sect, s, 0))
1780                                         abort = 1;
1781                         }
1782                         if (abort) {
1783                                 conf->recovery_disabled =
1784                                         mddev->recovery_disabled;
1785                                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1786                                 md_done_sync(mddev, r1_bio->sectors, 0);
1787                                 put_buf(r1_bio);
1788                                 return 0;
1789                         }
1790                         /* Try next page */
1791                         sectors -= s;
1792                         sect += s;
1793                         idx++;
1794                         continue;
1795                 }
1796
1797                 start = d;
1798                 /* write it back and re-read */
1799                 while (d != r1_bio->read_disk) {
1800                         if (d == 0)
1801                                 d = conf->raid_disks * 2;
1802                         d--;
1803                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1804                                 continue;
1805                         rdev = conf->mirrors[d].rdev;
1806                         if (r1_sync_page_io(rdev, sect, s,
1807                                             bio->bi_io_vec[idx].bv_page,
1808                                             WRITE) == 0) {
1809                                 r1_bio->bios[d]->bi_end_io = NULL;
1810                                 rdev_dec_pending(rdev, mddev);
1811                         }
1812                 }
1813                 d = start;
1814                 while (d != r1_bio->read_disk) {
1815                         if (d == 0)
1816                                 d = conf->raid_disks * 2;
1817                         d--;
1818                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1819                                 continue;
1820                         rdev = conf->mirrors[d].rdev;
1821                         if (r1_sync_page_io(rdev, sect, s,
1822                                             bio->bi_io_vec[idx].bv_page,
1823                                             READ) != 0)
1824                                 atomic_add(s, &rdev->corrected_errors);
1825                 }
1826                 sectors -= s;
1827                 sect += s;
1828                 idx ++;
1829         }
1830         set_bit(R1BIO_Uptodate, &r1_bio->state);
1831         set_bit(BIO_UPTODATE, &bio->bi_flags);
1832         return 1;
1833 }
1834
1835 static int process_checks(struct r1bio *r1_bio)
1836 {
1837         /* We have read all readable devices.  If we haven't
1838          * got the block, then there is no hope left.
1839          * If we have, then we want to do a comparison
1840          * and skip the write if everything is the same.
1841          * If any blocks failed to read, then we need to
1842          * attempt an over-write
1843          */
1844         struct mddev *mddev = r1_bio->mddev;
1845         struct r1conf *conf = mddev->private;
1846         int primary;
1847         int i;
1848         int vcnt;
1849
1850         for (primary = 0; primary < conf->raid_disks * 2; primary++)
1851                 if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1852                     test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
1853                         r1_bio->bios[primary]->bi_end_io = NULL;
1854                         rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1855                         break;
1856                 }
1857         r1_bio->read_disk = primary;
1858         vcnt = (r1_bio->sectors + PAGE_SIZE / 512 - 1) >> (PAGE_SHIFT - 9);
1859         for (i = 0; i < conf->raid_disks * 2; i++) {
1860                 int j;
1861                 struct bio *pbio = r1_bio->bios[primary];
1862                 struct bio *sbio = r1_bio->bios[i];
1863                 int size;
1864
1865                 if (r1_bio->bios[i]->bi_end_io != end_sync_read)
1866                         continue;
1867
1868                 if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
1869                         for (j = vcnt; j-- ; ) {
1870                                 struct page *p, *s;
1871                                 p = pbio->bi_io_vec[j].bv_page;
1872                                 s = sbio->bi_io_vec[j].bv_page;
1873                                 if (memcmp(page_address(p),
1874                                            page_address(s),
1875                                            sbio->bi_io_vec[j].bv_len))
1876                                         break;
1877                         }
1878                 } else
1879                         j = 0;
1880                 if (j >= 0)
1881                         atomic64_add(r1_bio->sectors, &mddev->resync_mismatches);
1882                 if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
1883                               && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
1884                         /* No need to write to this device. */
1885                         sbio->bi_end_io = NULL;
1886                         rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1887                         continue;
1888                 }
1889                 /* fixup the bio for reuse */
1890                 sbio->bi_vcnt = vcnt;
1891                 sbio->bi_size = r1_bio->sectors << 9;
1892                 sbio->bi_idx = 0;
1893                 sbio->bi_phys_segments = 0;
1894                 sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1895                 sbio->bi_flags |= 1 << BIO_UPTODATE;
1896                 sbio->bi_next = NULL;
1897                 sbio->bi_sector = r1_bio->sector +
1898                         conf->mirrors[i].rdev->data_offset;
1899                 sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1900                 size = sbio->bi_size;
1901                 for (j = 0; j < vcnt ; j++) {
1902                         struct bio_vec *bi;
1903                         bi = &sbio->bi_io_vec[j];
1904                         bi->bv_offset = 0;
1905                         if (size > PAGE_SIZE)
1906                                 bi->bv_len = PAGE_SIZE;
1907                         else
1908                                 bi->bv_len = size;
1909                         size -= PAGE_SIZE;
1910                         memcpy(page_address(bi->bv_page),
1911                                page_address(pbio->bi_io_vec[j].bv_page),
1912                                PAGE_SIZE);
1913                 }
1914         }
1915         return 0;
1916 }
1917
1918 static void sync_request_write(struct mddev *mddev, struct r1bio *r1_bio)
1919 {
1920         struct r1conf *conf = mddev->private;
1921         int i;
1922         int disks = conf->raid_disks * 2;
1923         struct bio *bio, *wbio;
1924
1925         bio = r1_bio->bios[r1_bio->read_disk];
1926
1927         if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
1928                 /* ouch - failed to read all of that. */
1929                 if (!fix_sync_read_error(r1_bio))
1930                         return;
1931
1932         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1933                 if (process_checks(r1_bio) < 0)
1934                         return;
1935         /*
1936          * schedule writes
1937          */
1938         atomic_set(&r1_bio->remaining, 1);
1939         for (i = 0; i < disks ; i++) {
1940                 wbio = r1_bio->bios[i];
1941                 if (wbio->bi_end_io == NULL ||
1942                     (wbio->bi_end_io == end_sync_read &&
1943                      (i == r1_bio->read_disk ||
1944                       !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
1945                         continue;
1946
1947                 wbio->bi_rw = WRITE;
1948                 wbio->bi_end_io = end_sync_write;
1949                 atomic_inc(&r1_bio->remaining);
1950                 md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1951
1952                 generic_make_request(wbio);
1953         }
1954
1955         if (atomic_dec_and_test(&r1_bio->remaining)) {
1956                 /* if we're here, all write(s) have completed, so clean up */
1957                 int s = r1_bio->sectors;
1958                 if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
1959                     test_bit(R1BIO_WriteError, &r1_bio->state))
1960                         reschedule_retry(r1_bio);
1961                 else {
1962                         put_buf(r1_bio);
1963                         md_done_sync(mddev, s, 1);
1964                 }
1965         }
1966 }
1967
1968 /*
1969  * This is a kernel thread which:
1970  *
1971  *      1.      Retries failed read operations on working mirrors.
1972  *      2.      Updates the raid superblock when problems encounter.
1973  *      3.      Performs writes following reads for array synchronising.
1974  */
1975
1976 static void fix_read_error(struct r1conf *conf, int read_disk,
1977                            sector_t sect, int sectors)
1978 {
1979         struct mddev *mddev = conf->mddev;
1980         while(sectors) {
1981                 int s = sectors;
1982                 int d = read_disk;
1983                 int success = 0;
1984                 int start;
1985                 struct md_rdev *rdev;
1986
1987                 if (s > (PAGE_SIZE>>9))
1988                         s = PAGE_SIZE >> 9;
1989
1990                 do {
1991                         /* Note: no rcu protection needed here
1992                          * as this is synchronous in the raid1d thread
1993                          * which is the thread that might remove
1994                          * a device.  If raid1d ever becomes multi-threaded....
1995                          */
1996                         sector_t first_bad;
1997                         int bad_sectors;
1998
1999                         rdev = conf->mirrors[d].rdev;
2000                         if (rdev &&
2001                             (test_bit(In_sync, &rdev->flags) ||
2002                              (!test_bit(Faulty, &rdev->flags) &&
2003                               rdev->recovery_offset >= sect + s)) &&
2004                             is_badblock(rdev, sect, s,
2005                                         &first_bad, &bad_sectors) == 0 &&
2006                             sync_page_io(rdev, sect, s<<9,
2007                                          conf->tmppage, READ, false))
2008                                 success = 1;
2009                         else {
2010                                 d++;
2011                                 if (d == conf->raid_disks * 2)
2012                                         d = 0;
2013                         }
2014                 } while (!success && d != read_disk);
2015
2016                 if (!success) {
2017                         /* Cannot read from anywhere - mark it bad */
2018                         struct md_rdev *rdev = conf->mirrors[read_disk].rdev;
2019                         if (!rdev_set_badblocks(rdev, sect, s, 0))
2020                                 md_error(mddev, rdev);
2021                         break;
2022                 }
2023                 /* write it back and re-read */
2024                 start = d;
2025                 while (d != read_disk) {
2026                         if (d==0)
2027                                 d = conf->raid_disks * 2;
2028                         d--;
2029                         rdev = conf->mirrors[d].rdev;
2030                         if (rdev &&
2031                             test_bit(In_sync, &rdev->flags))
2032                                 r1_sync_page_io(rdev, sect, s,
2033                                                 conf->tmppage, WRITE);
2034                 }
2035                 d = start;
2036                 while (d != read_disk) {
2037                         char b[BDEVNAME_SIZE];
2038                         if (d==0)
2039                                 d = conf->raid_disks * 2;
2040                         d--;
2041                         rdev = conf->mirrors[d].rdev;
2042                         if (rdev &&
2043                             test_bit(In_sync, &rdev->flags)) {
2044                                 if (r1_sync_page_io(rdev, sect, s,
2045                                                     conf->tmppage, READ)) {
2046                                         atomic_add(s, &rdev->corrected_errors);
2047                                         printk(KERN_INFO
2048                                                "md/raid1:%s: read error corrected "
2049                                                "(%d sectors at %llu on %s)\n",
2050                                                mdname(mddev), s,
2051                                                (unsigned long long)(sect +
2052                                                    rdev->data_offset),
2053                                                bdevname(rdev->bdev, b));
2054                                 }
2055                         }
2056                 }
2057                 sectors -= s;
2058                 sect += s;
2059         }
2060 }
2061
2062 static void bi_complete(struct bio *bio, int error)
2063 {
2064         complete((struct completion *)bio->bi_private);
2065 }
2066
2067 static int submit_bio_wait(int rw, struct bio *bio)
2068 {
2069         struct completion event;
2070         rw |= REQ_SYNC;
2071
2072         init_completion(&event);
2073         bio->bi_private = &event;
2074         bio->bi_end_io = bi_complete;
2075         submit_bio(rw, bio);
2076         wait_for_completion(&event);
2077
2078         return test_bit(BIO_UPTODATE, &bio->bi_flags);
2079 }
2080
2081 static int narrow_write_error(struct r1bio *r1_bio, int i)
2082 {
2083         struct mddev *mddev = r1_bio->mddev;
2084         struct r1conf *conf = mddev->private;
2085         struct md_rdev *rdev = conf->mirrors[i].rdev;
2086         int vcnt, idx;
2087         struct bio_vec *vec;
2088
2089         /* bio has the data to be written to device 'i' where
2090          * we just recently had a write error.
2091          * We repeatedly clone the bio and trim down to one block,
2092          * then try the write.  Where the write fails we record
2093          * a bad block.
2094          * It is conceivable that the bio doesn't exactly align with
2095          * blocks.  We must handle this somehow.
2096          *
2097          * We currently own a reference on the rdev.
2098          */
2099
2100         int block_sectors;
2101         sector_t sector;
2102         int sectors;
2103         int sect_to_write = r1_bio->sectors;
2104         int ok = 1;
2105
2106         if (rdev->badblocks.shift < 0)
2107                 return 0;
2108
2109         block_sectors = 1 << rdev->badblocks.shift;
2110         sector = r1_bio->sector;
2111         sectors = ((sector + block_sectors)
2112                    & ~(sector_t)(block_sectors - 1))
2113                 - sector;
2114
2115         if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
2116                 vcnt = r1_bio->behind_page_count;
2117                 vec = r1_bio->behind_bvecs;
2118                 idx = 0;
2119                 while (vec[idx].bv_page == NULL)
2120                         idx++;
2121         } else {
2122                 vcnt = r1_bio->master_bio->bi_vcnt;
2123                 vec = r1_bio->master_bio->bi_io_vec;
2124                 idx = r1_bio->master_bio->bi_idx;
2125         }
2126         while (sect_to_write) {
2127                 struct bio *wbio;
2128                 if (sectors > sect_to_write)
2129                         sectors = sect_to_write;
2130                 /* Write at 'sector' for 'sectors'*/
2131
2132                 wbio = bio_alloc_mddev(GFP_NOIO, vcnt, mddev);
2133                 memcpy(wbio->bi_io_vec, vec, vcnt * sizeof(struct bio_vec));
2134                 wbio->bi_sector = r1_bio->sector;
2135                 wbio->bi_rw = WRITE;
2136                 wbio->bi_vcnt = vcnt;
2137                 wbio->bi_size = r1_bio->sectors << 9;
2138                 wbio->bi_idx = idx;
2139
2140                 md_trim_bio(wbio, sector - r1_bio->sector, sectors);
2141                 wbio->bi_sector += rdev->data_offset;
2142                 wbio->bi_bdev = rdev->bdev;
2143                 if (submit_bio_wait(WRITE, wbio) == 0)
2144                         /* failure! */
2145                         ok = rdev_set_badblocks(rdev, sector,
2146                                                 sectors, 0)
2147                                 && ok;
2148
2149                 bio_put(wbio);
2150                 sect_to_write -= sectors;
2151                 sector += sectors;
2152                 sectors = block_sectors;
2153         }
2154         return ok;
2155 }
2156
2157 static void handle_sync_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2158 {
2159         int m;
2160         int s = r1_bio->sectors;
2161         for (m = 0; m < conf->raid_disks * 2 ; m++) {
2162                 struct md_rdev *rdev = conf->mirrors[m].rdev;
2163                 struct bio *bio = r1_bio->bios[m];
2164                 if (bio->bi_end_io == NULL)
2165                         continue;
2166                 if (test_bit(BIO_UPTODATE, &bio->bi_flags) &&
2167                     test_bit(R1BIO_MadeGood, &r1_bio->state)) {
2168                         rdev_clear_badblocks(rdev, r1_bio->sector, s, 0);
2169                 }
2170                 if (!test_bit(BIO_UPTODATE, &bio->bi_flags) &&
2171                     test_bit(R1BIO_WriteError, &r1_bio->state)) {
2172                         if (!rdev_set_badblocks(rdev, r1_bio->sector, s, 0))
2173                                 md_error(conf->mddev, rdev);
2174                 }
2175         }
2176         put_buf(r1_bio);
2177         md_done_sync(conf->mddev, s, 1);
2178 }
2179
2180 static void handle_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2181 {
2182         int m;
2183         for (m = 0; m < conf->raid_disks * 2 ; m++)
2184                 if (r1_bio->bios[m] == IO_MADE_GOOD) {
2185                         struct md_rdev *rdev = conf->mirrors[m].rdev;
2186                         rdev_clear_badblocks(rdev,
2187                                              r1_bio->sector,
2188                                              r1_bio->sectors, 0);
2189                         rdev_dec_pending(rdev, conf->mddev);
2190                 } else if (r1_bio->bios[m] != NULL) {
2191                         /* This drive got a write error.  We need to
2192                          * narrow down and record precise write
2193                          * errors.
2194                          */
2195                         if (!narrow_write_error(r1_bio, m)) {
2196                                 md_error(conf->mddev,
2197                                          conf->mirrors[m].rdev);
2198                                 /* an I/O failed, we can't clear the bitmap */
2199                                 set_bit(R1BIO_Degraded, &r1_bio->state);
2200                         }
2201                         rdev_dec_pending(conf->mirrors[m].rdev,
2202                                          conf->mddev);
2203                 }
2204         if (test_bit(R1BIO_WriteError, &r1_bio->state))
2205                 close_write(r1_bio);
2206         raid_end_bio_io(r1_bio);
2207 }
2208
2209 static void handle_read_error(struct r1conf *conf, struct r1bio *r1_bio)
2210 {
2211         int disk;
2212         int max_sectors;
2213         struct mddev *mddev = conf->mddev;
2214         struct bio *bio;
2215         char b[BDEVNAME_SIZE];
2216         struct md_rdev *rdev;
2217
2218         clear_bit(R1BIO_ReadError, &r1_bio->state);
2219         /* we got a read error. Maybe the drive is bad.  Maybe just
2220          * the block and we can fix it.
2221          * We freeze all other IO, and try reading the block from
2222          * other devices.  When we find one, we re-write
2223          * and check it that fixes the read error.
2224          * This is all done synchronously while the array is
2225          * frozen
2226          */
2227         if (mddev->ro == 0) {
2228                 freeze_array(conf);
2229                 fix_read_error(conf, r1_bio->read_disk,
2230                                r1_bio->sector, r1_bio->sectors);
2231                 unfreeze_array(conf);
2232         } else
2233                 md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
2234         rdev_dec_pending(conf->mirrors[r1_bio->read_disk].rdev, conf->mddev);
2235
2236         bio = r1_bio->bios[r1_bio->read_disk];
2237         bdevname(bio->bi_bdev, b);
2238 read_more:
2239         disk = read_balance(conf, r1_bio, &max_sectors);
2240         if (disk == -1) {
2241                 printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O"
2242                        " read error for block %llu\n",
2243                        mdname(mddev), b, (unsigned long long)r1_bio->sector);
2244                 raid_end_bio_io(r1_bio);
2245         } else {
2246                 const unsigned long do_sync
2247                         = r1_bio->master_bio->bi_rw & REQ_SYNC;
2248                 if (bio) {
2249                         r1_bio->bios[r1_bio->read_disk] =
2250                                 mddev->ro ? IO_BLOCKED : NULL;
2251                         bio_put(bio);
2252                 }
2253                 r1_bio->read_disk = disk;
2254                 bio = bio_clone_mddev(r1_bio->master_bio, GFP_NOIO, mddev);
2255                 md_trim_bio(bio, r1_bio->sector - bio->bi_sector, max_sectors);
2256                 r1_bio->bios[r1_bio->read_disk] = bio;
2257                 rdev = conf->mirrors[disk].rdev;
2258                 printk_ratelimited(KERN_ERR
2259                                    "md/raid1:%s: redirecting sector %llu"
2260                                    " to other mirror: %s\n",
2261                                    mdname(mddev),
2262                                    (unsigned long long)r1_bio->sector,
2263                                    bdevname(rdev->bdev, b));
2264                 bio->bi_sector = r1_bio->sector + rdev->data_offset;
2265                 bio->bi_bdev = rdev->bdev;
2266                 bio->bi_end_io = raid1_end_read_request;
2267                 bio->bi_rw = READ | do_sync;
2268                 bio->bi_private = r1_bio;
2269                 if (max_sectors < r1_bio->sectors) {
2270                         /* Drat - have to split this up more */
2271                         struct bio *mbio = r1_bio->master_bio;
2272                         int sectors_handled = (r1_bio->sector + max_sectors
2273                                                - mbio->bi_sector);
2274                         r1_bio->sectors = max_sectors;
2275                         spin_lock_irq(&conf->device_lock);
2276                         if (mbio->bi_phys_segments == 0)
2277                                 mbio->bi_phys_segments = 2;
2278                         else
2279                                 mbio->bi_phys_segments++;
2280                         spin_unlock_irq(&conf->device_lock);
2281                         generic_make_request(bio);
2282                         bio = NULL;
2283
2284                         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
2285
2286                         r1_bio->master_bio = mbio;
2287                         r1_bio->sectors = (mbio->bi_size >> 9)
2288                                           - sectors_handled;
2289                         r1_bio->state = 0;
2290                         set_bit(R1BIO_ReadError, &r1_bio->state);
2291                         r1_bio->mddev = mddev;
2292                         r1_bio->sector = mbio->bi_sector + sectors_handled;
2293
2294                         goto read_more;
2295                 } else
2296                         generic_make_request(bio);
2297         }
2298 }
2299
2300 static void raid1d(struct md_thread *thread)
2301 {
2302         struct mddev *mddev = thread->mddev;
2303         struct r1bio *r1_bio;
2304         unsigned long flags;
2305         struct r1conf *conf = mddev->private;
2306         struct list_head *head = &conf->retry_list;
2307         struct blk_plug plug;
2308
2309         md_check_recovery(mddev);
2310
2311         blk_start_plug(&plug);
2312         for (;;) {
2313
2314                 flush_pending_writes(conf);
2315
2316                 spin_lock_irqsave(&conf->device_lock, flags);
2317                 if (list_empty(head)) {
2318                         spin_unlock_irqrestore(&conf->device_lock, flags);
2319                         break;
2320                 }
2321                 r1_bio = list_entry(head->prev, struct r1bio, retry_list);
2322                 list_del(head->prev);
2323                 conf->nr_queued--;
2324                 spin_unlock_irqrestore(&conf->device_lock, flags);
2325
2326                 mddev = r1_bio->mddev;
2327                 conf = mddev->private;
2328                 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
2329                         if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2330                             test_bit(R1BIO_WriteError, &r1_bio->state))
2331                                 handle_sync_write_finished(conf, r1_bio);
2332                         else
2333                                 sync_request_write(mddev, r1_bio);
2334                 } else if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2335                            test_bit(R1BIO_WriteError, &r1_bio->state))
2336                         handle_write_finished(conf, r1_bio);
2337                 else if (test_bit(R1BIO_ReadError, &r1_bio->state))
2338                         handle_read_error(conf, r1_bio);
2339                 else
2340                         /* just a partial read to be scheduled from separate
2341                          * context
2342                          */
2343                         generic_make_request(r1_bio->bios[r1_bio->read_disk]);
2344
2345                 cond_resched();
2346                 if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
2347                         md_check_recovery(mddev);
2348         }
2349         blk_finish_plug(&plug);
2350 }
2351
2352
2353 static int init_resync(struct r1conf *conf)
2354 {
2355         int buffs;
2356
2357         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
2358         BUG_ON(conf->r1buf_pool);
2359         conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
2360                                           conf->poolinfo);
2361         if (!conf->r1buf_pool)
2362                 return -ENOMEM;
2363         conf->next_resync = 0;
2364         return 0;
2365 }
2366
2367 /*
2368  * perform a "sync" on one "block"
2369  *
2370  * We need to make sure that no normal I/O request - particularly write
2371  * requests - conflict with active sync requests.
2372  *
2373  * This is achieved by tracking pending requests and a 'barrier' concept
2374  * that can be installed to exclude normal IO requests.
2375  */
2376
2377 static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster)
2378 {
2379         struct r1conf *conf = mddev->private;
2380         struct r1bio *r1_bio;
2381         struct bio *bio;
2382         sector_t max_sector, nr_sectors;
2383         int disk = -1;
2384         int i;
2385         int wonly = -1;
2386         int write_targets = 0, read_targets = 0;
2387         sector_t sync_blocks;
2388         int still_degraded = 0;
2389         int good_sectors = RESYNC_SECTORS;
2390         int min_bad = 0; /* number of sectors that are bad in all devices */
2391
2392         if (!conf->r1buf_pool)
2393                 if (init_resync(conf))
2394                         return 0;
2395
2396         max_sector = mddev->dev_sectors;
2397         if (sector_nr >= max_sector) {
2398                 /* If we aborted, we need to abort the
2399                  * sync on the 'current' bitmap chunk (there will
2400                  * only be one in raid1 resync.
2401                  * We can find the current addess in mddev->curr_resync
2402                  */
2403                 if (mddev->curr_resync < max_sector) /* aborted */
2404                         bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
2405                                                 &sync_blocks, 1);
2406                 else /* completed sync */
2407                         conf->fullsync = 0;
2408
2409                 bitmap_close_sync(mddev->bitmap);
2410                 close_sync(conf);
2411                 return 0;
2412         }
2413
2414         if (mddev->bitmap == NULL &&
2415             mddev->recovery_cp == MaxSector &&
2416             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
2417             conf->fullsync == 0) {
2418                 *skipped = 1;
2419                 return max_sector - sector_nr;
2420         }
2421         /* before building a request, check if we can skip these blocks..
2422          * This call the bitmap_start_sync doesn't actually record anything
2423          */
2424         if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
2425             !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2426                 /* We can skip this block, and probably several more */
2427                 *skipped = 1;
2428                 return sync_blocks;
2429         }
2430         /*
2431          * If there is non-resync activity waiting for a turn,
2432          * and resync is going fast enough,
2433          * then let it though before starting on this new sync request.
2434          */
2435         if (!go_faster && conf->nr_waiting)
2436                 msleep_interruptible(1000);
2437
2438         bitmap_cond_end_sync(mddev->bitmap, sector_nr);
2439         r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
2440         raise_barrier(conf);
2441
2442         conf->next_resync = sector_nr;
2443
2444         rcu_read_lock();
2445         /*
2446          * If we get a correctably read error during resync or recovery,
2447          * we might want to read from a different device.  So we
2448          * flag all drives that could conceivably be read from for READ,
2449          * and any others (which will be non-In_sync devices) for WRITE.
2450          * If a read fails, we try reading from something else for which READ
2451          * is OK.
2452          */
2453
2454         r1_bio->mddev = mddev;
2455         r1_bio->sector = sector_nr;
2456         r1_bio->state = 0;
2457         set_bit(R1BIO_IsSync, &r1_bio->state);
2458
2459         for (i = 0; i < conf->raid_disks * 2; i++) {
2460                 struct md_rdev *rdev;
2461                 bio = r1_bio->bios[i];
2462
2463                 /* take from bio_init */
2464                 bio->bi_next = NULL;
2465                 bio->bi_flags &= ~(BIO_POOL_MASK-1);
2466                 bio->bi_flags |= 1 << BIO_UPTODATE;
2467                 bio->bi_rw = READ;
2468                 bio->bi_vcnt = 0;
2469                 bio->bi_idx = 0;
2470                 bio->bi_phys_segments = 0;
2471                 bio->bi_size = 0;
2472                 bio->bi_end_io = NULL;
2473                 bio->bi_private = NULL;
2474
2475                 rdev = rcu_dereference(conf->mirrors[i].rdev);
2476                 if (rdev == NULL ||
2477                     test_bit(Faulty, &rdev->flags)) {
2478                         if (i < conf->raid_disks)
2479                                 still_degraded = 1;
2480                 } else if (!test_bit(In_sync, &rdev->flags)) {
2481                         bio->bi_rw = WRITE;
2482                         bio->bi_end_io = end_sync_write;
2483                         write_targets ++;
2484                 } else {
2485                         /* may need to read from here */
2486                         sector_t first_bad = MaxSector;
2487                         int bad_sectors;
2488
2489                         if (is_badblock(rdev, sector_nr, good_sectors,
2490                                         &first_bad, &bad_sectors)) {
2491                                 if (first_bad > sector_nr)
2492                                         good_sectors = first_bad - sector_nr;
2493                                 else {
2494                                         bad_sectors -= (sector_nr - first_bad);
2495                                         if (min_bad == 0 ||
2496                                             min_bad > bad_sectors)
2497                                                 min_bad = bad_sectors;
2498                                 }
2499                         }
2500                         if (sector_nr < first_bad) {
2501                                 if (test_bit(WriteMostly, &rdev->flags)) {
2502                                         if (wonly < 0)
2503                                                 wonly = i;
2504                                 } else {
2505                                         if (disk < 0)
2506                                                 disk = i;
2507                                 }
2508                                 bio->bi_rw = READ;
2509                                 bio->bi_end_io = end_sync_read;
2510                                 read_targets++;
2511                         } else if (!test_bit(WriteErrorSeen, &rdev->flags) &&
2512                                 test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
2513                                 !test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) {
2514                                 /*
2515                                  * The device is suitable for reading (InSync),
2516                                  * but has bad block(s) here. Let's try to correct them,
2517                                  * if we are doing resync or repair. Otherwise, leave
2518                                  * this device alone for this sync request.
2519                                  */
2520                                 bio->bi_rw = WRITE;
2521                                 bio->bi_end_io = end_sync_write;
2522                                 write_targets++;
2523                         }
2524                 }
2525                 if (bio->bi_end_io) {
2526                         atomic_inc(&rdev->nr_pending);
2527                         bio->bi_sector = sector_nr + rdev->data_offset;
2528                         bio->bi_bdev = rdev->bdev;
2529                         bio->bi_private = r1_bio;
2530                 }
2531         }
2532         rcu_read_unlock();
2533         if (disk < 0)
2534                 disk = wonly;
2535         r1_bio->read_disk = disk;
2536
2537         if (read_targets == 0 && min_bad > 0) {
2538                 /* These sectors are bad on all InSync devices, so we
2539                  * need to mark them bad on all write targets
2540                  */
2541                 int ok = 1;
2542                 for (i = 0 ; i < conf->raid_disks * 2 ; i++)
2543                         if (r1_bio->bios[i]->bi_end_io == end_sync_write) {
2544                                 struct md_rdev *rdev = conf->mirrors[i].rdev;
2545                                 ok = rdev_set_badblocks(rdev, sector_nr,
2546                                                         min_bad, 0
2547                                         ) && ok;
2548                         }
2549                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
2550                 *skipped = 1;
2551                 put_buf(r1_bio);
2552
2553                 if (!ok) {
2554                         /* Cannot record the badblocks, so need to
2555                          * abort the resync.
2556                          * If there are multiple read targets, could just
2557                          * fail the really bad ones ???
2558                          */
2559                         conf->recovery_disabled = mddev->recovery_disabled;
2560                         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2561                         return 0;
2562                 } else
2563                         return min_bad;
2564
2565         }
2566         if (min_bad > 0 && min_bad < good_sectors) {
2567                 /* only resync enough to reach the next bad->good
2568                  * transition */
2569                 good_sectors = min_bad;
2570         }
2571
2572         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
2573                 /* extra read targets are also write targets */
2574                 write_targets += read_targets-1;
2575
2576         if (write_targets == 0 || read_targets == 0) {
2577                 /* There is nowhere to write, so all non-sync
2578                  * drives must be failed - so we are finished
2579                  */
2580                 sector_t rv;
2581                 if (min_bad > 0)
2582                         max_sector = sector_nr + min_bad;
2583                 rv = max_sector - sector_nr;
2584                 *skipped = 1;
2585                 put_buf(r1_bio);
2586                 return rv;
2587         }
2588
2589         if (max_sector > mddev->resync_max)
2590                 max_sector = mddev->resync_max; /* Don't do IO beyond here */
2591         if (max_sector > sector_nr + good_sectors)
2592                 max_sector = sector_nr + good_sectors;
2593         nr_sectors = 0;
2594         sync_blocks = 0;
2595         do {
2596                 struct page *page;
2597                 int len = PAGE_SIZE;
2598                 if (sector_nr + (len>>9) > max_sector)
2599                         len = (max_sector - sector_nr) << 9;
2600                 if (len == 0)
2601                         break;
2602                 if (sync_blocks == 0) {
2603                         if (!bitmap_start_sync(mddev->bitmap, sector_nr,
2604                                                &sync_blocks, still_degraded) &&
2605                             !conf->fullsync &&
2606                             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2607                                 break;
2608                         BUG_ON(sync_blocks < (PAGE_SIZE>>9));
2609                         if ((len >> 9) > sync_blocks)
2610                                 len = sync_blocks<<9;
2611                 }
2612
2613                 for (i = 0 ; i < conf->raid_disks * 2; i++) {
2614                         bio = r1_bio->bios[i];
2615                         if (bio->bi_end_io) {
2616                                 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
2617                                 if (bio_add_page(bio, page, len, 0) == 0) {
2618                                         /* stop here */
2619                                         bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
2620                                         while (i > 0) {
2621                                                 i--;
2622                                                 bio = r1_bio->bios[i];
2623                                                 if (bio->bi_end_io==NULL)
2624                                                         continue;
2625                                                 /* remove last page from this bio */
2626                                                 bio->bi_vcnt--;
2627                                                 bio->bi_size -= len;
2628                                                 bio->bi_flags &= ~(1<< BIO_SEG_VALID);
2629                                         }
2630                                         goto bio_full;
2631                                 }
2632                         }
2633                 }
2634                 nr_sectors += len>>9;
2635                 sector_nr += len>>9;
2636                 sync_blocks -= (len>>9);
2637         } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
2638  bio_full:
2639         r1_bio->sectors = nr_sectors;
2640
2641         /* For a user-requested sync, we read all readable devices and do a
2642          * compare
2643          */
2644         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2645                 atomic_set(&r1_bio->remaining, read_targets);
2646                 for (i = 0; i < conf->raid_disks * 2 && read_targets; i++) {
2647                         bio = r1_bio->bios[i];
2648                         if (bio->bi_end_io == end_sync_read) {
2649                                 read_targets--;
2650                                 md_sync_acct(bio->bi_bdev, nr_sectors);
2651                                 generic_make_request(bio);
2652                         }
2653                 }
2654         } else {
2655                 atomic_set(&r1_bio->remaining, 1);
2656                 bio = r1_bio->bios[r1_bio->read_disk];
2657                 md_sync_acct(bio->bi_bdev, nr_sectors);
2658                 generic_make_request(bio);
2659
2660         }
2661         return nr_sectors;
2662 }
2663
2664 static sector_t raid1_size(struct mddev *mddev, sector_t sectors, int raid_disks)
2665 {
2666         if (sectors)
2667                 return sectors;
2668
2669         return mddev->dev_sectors;
2670 }
2671
2672 static struct r1conf *setup_conf(struct mddev *mddev)
2673 {
2674         struct r1conf *conf;
2675         int i;
2676         struct raid1_info *disk;
2677         struct md_rdev *rdev;
2678         int err = -ENOMEM;
2679
2680         conf = kzalloc(sizeof(struct r1conf), GFP_KERNEL);
2681         if (!conf)
2682                 goto abort;
2683
2684         conf->mirrors = kzalloc(sizeof(struct raid1_info)
2685                                 * mddev->raid_disks * 2,
2686                                  GFP_KERNEL);
2687         if (!conf->mirrors)
2688                 goto abort;
2689
2690         conf->tmppage = alloc_page(GFP_KERNEL);
2691         if (!conf->tmppage)
2692                 goto abort;
2693
2694         conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
2695         if (!conf->poolinfo)
2696                 goto abort;
2697         conf->poolinfo->raid_disks = mddev->raid_disks * 2;
2698         conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2699                                           r1bio_pool_free,
2700                                           conf->poolinfo);
2701         if (!conf->r1bio_pool)
2702                 goto abort;
2703
2704         conf->poolinfo->mddev = mddev;
2705
2706         err = -EINVAL;
2707         spin_lock_init(&conf->device_lock);
2708         rdev_for_each(rdev, mddev) {
2709                 struct request_queue *q;
2710                 int disk_idx = rdev->raid_disk;
2711                 if (disk_idx >= mddev->raid_disks
2712                     || disk_idx < 0)
2713                         continue;
2714                 if (test_bit(Replacement, &rdev->flags))
2715                         disk = conf->mirrors + mddev->raid_disks + disk_idx;
2716                 else
2717                         disk = conf->mirrors + disk_idx;
2718
2719                 if (disk->rdev)
2720                         goto abort;
2721                 disk->rdev = rdev;
2722                 q = bdev_get_queue(rdev->bdev);
2723                 if (q->merge_bvec_fn)
2724                         mddev->merge_check_needed = 1;
2725
2726                 disk->head_position = 0;
2727                 disk->seq_start = MaxSector;
2728         }
2729         conf->raid_disks = mddev->raid_disks;
2730         conf->mddev = mddev;
2731         INIT_LIST_HEAD(&conf->retry_list);
2732
2733         spin_lock_init(&conf->resync_lock);
2734         init_waitqueue_head(&conf->wait_barrier);
2735
2736         bio_list_init(&conf->pending_bio_list);
2737         conf->pending_count = 0;
2738         conf->recovery_disabled = mddev->recovery_disabled - 1;
2739
2740         err = -EIO;
2741         for (i = 0; i < conf->raid_disks * 2; i++) {
2742
2743                 disk = conf->mirrors + i;
2744
2745                 if (i < conf->raid_disks &&
2746                     disk[conf->raid_disks].rdev) {
2747                         /* This slot has a replacement. */
2748                         if (!disk->rdev) {
2749                                 /* No original, just make the replacement
2750                                  * a recovering spare
2751                                  */
2752                                 disk->rdev =
2753                                         disk[conf->raid_disks].rdev;
2754                                 disk[conf->raid_disks].rdev = NULL;
2755                         } else if (!test_bit(In_sync, &disk->rdev->flags))
2756                                 /* Original is not in_sync - bad */
2757                                 goto abort;
2758                 }
2759
2760                 if (!disk->rdev ||
2761                     !test_bit(In_sync, &disk->rdev->flags)) {
2762                         disk->head_position = 0;
2763                         if (disk->rdev &&
2764                             (disk->rdev->saved_raid_disk < 0))
2765                                 conf->fullsync = 1;
2766                 }
2767         }
2768
2769         err = -ENOMEM;
2770         conf->thread = md_register_thread(raid1d, mddev, "raid1");
2771         if (!conf->thread) {
2772                 printk(KERN_ERR
2773                        "md/raid1:%s: couldn't allocate thread\n",
2774                        mdname(mddev));
2775                 goto abort;
2776         }
2777
2778         return conf;
2779
2780  abort:
2781         if (conf) {
2782                 if (conf->r1bio_pool)
2783                         mempool_destroy(conf->r1bio_pool);
2784                 kfree(conf->mirrors);
2785                 safe_put_page(conf->tmppage);
2786                 kfree(conf->poolinfo);
2787                 kfree(conf);
2788         }
2789         return ERR_PTR(err);
2790 }
2791
2792 static int stop(struct mddev *mddev);
2793 static int run(struct mddev *mddev)
2794 {
2795         struct r1conf *conf;
2796         int i;
2797         struct md_rdev *rdev;
2798         int ret;
2799         bool discard_supported = false;
2800
2801         if (mddev->level != 1) {
2802                 printk(KERN_ERR "md/raid1:%s: raid level not set to mirroring (%d)\n",
2803                        mdname(mddev), mddev->level);
2804                 return -EIO;
2805         }
2806         if (mddev->reshape_position != MaxSector) {
2807                 printk(KERN_ERR "md/raid1:%s: reshape_position set but not supported\n",
2808                        mdname(mddev));
2809                 return -EIO;
2810         }
2811         /*
2812          * copy the already verified devices into our private RAID1
2813          * bookkeeping area. [whatever we allocate in run(),
2814          * should be freed in stop()]
2815          */
2816         if (mddev->private == NULL)
2817                 conf = setup_conf(mddev);
2818         else
2819                 conf = mddev->private;
2820
2821         if (IS_ERR(conf))
2822                 return PTR_ERR(conf);
2823
2824         if (mddev->queue)
2825                 blk_queue_max_write_same_sectors(mddev->queue,
2826                                                  mddev->chunk_sectors);
2827         rdev_for_each(rdev, mddev) {
2828                 if (!mddev->gendisk)
2829                         continue;
2830                 disk_stack_limits(mddev->gendisk, rdev->bdev,
2831                                   rdev->data_offset << 9);
2832                 if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
2833                         discard_supported = true;
2834         }
2835
2836         mddev->degraded = 0;
2837         for (i=0; i < conf->raid_disks; i++)
2838                 if (conf->mirrors[i].rdev == NULL ||
2839                     !test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
2840                     test_bit(Faulty, &conf->mirrors[i].rdev->flags))
2841                         mddev->degraded++;
2842
2843         if (conf->raid_disks - mddev->degraded == 1)
2844                 mddev->recovery_cp = MaxSector;
2845
2846         if (mddev->recovery_cp != MaxSector)
2847                 printk(KERN_NOTICE "md/raid1:%s: not clean"
2848                        " -- starting background reconstruction\n",
2849                        mdname(mddev));
2850         printk(KERN_INFO
2851                 "md/raid1:%s: active with %d out of %d mirrors\n",
2852                 mdname(mddev), mddev->raid_disks - mddev->degraded,
2853                 mddev->raid_disks);
2854
2855         /*
2856          * Ok, everything is just fine now
2857          */
2858         mddev->thread = conf->thread;
2859         conf->thread = NULL;
2860         mddev->private = conf;
2861
2862         md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
2863
2864         if (mddev->queue) {
2865                 mddev->queue->backing_dev_info.congested_fn = raid1_congested;
2866                 mddev->queue->backing_dev_info.congested_data = mddev;
2867                 blk_queue_merge_bvec(mddev->queue, raid1_mergeable_bvec);
2868
2869                 if (discard_supported)
2870                         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
2871                                                 mddev->queue);
2872                 else
2873                         queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
2874                                                   mddev->queue);
2875         }
2876
2877         ret =  md_integrity_register(mddev);
2878         if (ret)
2879                 stop(mddev);
2880         return ret;
2881 }
2882
2883 static int stop(struct mddev *mddev)
2884 {
2885         struct r1conf *conf = mddev->private;
2886         struct bitmap *bitmap = mddev->bitmap;
2887
2888         /* wait for behind writes to complete */
2889         if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
2890                 printk(KERN_INFO "md/raid1:%s: behind writes in progress - waiting to stop.\n",
2891                        mdname(mddev));
2892                 /* need to kick something here to make sure I/O goes? */
2893                 wait_event(bitmap->behind_wait,
2894                            atomic_read(&bitmap->behind_writes) == 0);
2895         }
2896
2897         raise_barrier(conf);
2898         lower_barrier(conf);
2899
2900         md_unregister_thread(&mddev->thread);
2901         if (conf->r1bio_pool)
2902                 mempool_destroy(conf->r1bio_pool);
2903         kfree(conf->mirrors);
2904         kfree(conf->poolinfo);
2905         kfree(conf);
2906         mddev->private = NULL;
2907         return 0;
2908 }
2909
2910 static int raid1_resize(struct mddev *mddev, sector_t sectors)
2911 {
2912         /* no resync is happening, and there is enough space
2913          * on all devices, so we can resize.
2914          * We need to make sure resync covers any new space.
2915          * If the array is shrinking we should possibly wait until
2916          * any io in the removed space completes, but it hardly seems
2917          * worth it.
2918          */
2919         sector_t newsize = raid1_size(mddev, sectors, 0);
2920         if (mddev->external_size &&
2921             mddev->array_sectors > newsize)
2922                 return -EINVAL;
2923         if (mddev->bitmap) {
2924                 int ret = bitmap_resize(mddev->bitmap, newsize, 0, 0);
2925                 if (ret)
2926                         return ret;
2927         }
2928         md_set_array_sectors(mddev, newsize);
2929         set_capacity(mddev->gendisk, mddev->array_sectors);
2930         revalidate_disk(mddev->gendisk);
2931         if (sectors > mddev->dev_sectors &&
2932             mddev->recovery_cp > mddev->dev_sectors) {
2933                 mddev->recovery_cp = mddev->dev_sectors;
2934                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2935         }
2936         mddev->dev_sectors = sectors;
2937         mddev->resync_max_sectors = sectors;
2938         return 0;
2939 }
2940
2941 static int raid1_reshape(struct mddev *mddev)
2942 {
2943         /* We need to:
2944          * 1/ resize the r1bio_pool
2945          * 2/ resize conf->mirrors
2946          *
2947          * We allocate a new r1bio_pool if we can.
2948          * Then raise a device barrier and wait until all IO stops.
2949          * Then resize conf->mirrors and swap in the new r1bio pool.
2950          *
2951          * At the same time, we "pack" the devices so that all the missing
2952          * devices have the higher raid_disk numbers.
2953          */
2954         mempool_t *newpool, *oldpool;
2955         struct pool_info *newpoolinfo;
2956         struct raid1_info *newmirrors;
2957         struct r1conf *conf = mddev->private;
2958         int cnt, raid_disks;
2959         unsigned long flags;
2960         int d, d2, err;
2961
2962         /* Cannot change chunk_size, layout, or level */
2963         if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
2964             mddev->layout != mddev->new_layout ||
2965             mddev->level != mddev->new_level) {
2966                 mddev->new_chunk_sectors = mddev->chunk_sectors;
2967                 mddev->new_layout = mddev->layout;
2968                 mddev->new_level = mddev->level;
2969                 return -EINVAL;
2970         }
2971
2972         err = md_allow_write(mddev);
2973         if (err)
2974                 return err;
2975
2976         raid_disks = mddev->raid_disks + mddev->delta_disks;
2977
2978         if (raid_disks < conf->raid_disks) {
2979                 cnt=0;
2980                 for (d= 0; d < conf->raid_disks; d++)
2981                         if (conf->mirrors[d].rdev)
2982                                 cnt++;
2983                 if (cnt > raid_disks)
2984                         return -EBUSY;
2985         }
2986
2987         newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
2988         if (!newpoolinfo)
2989                 return -ENOMEM;
2990         newpoolinfo->mddev = mddev;
2991         newpoolinfo->raid_disks = raid_disks * 2;
2992
2993         newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2994                                  r1bio_pool_free, newpoolinfo);
2995         if (!newpool) {
2996                 kfree(newpoolinfo);
2997                 return -ENOMEM;
2998         }
2999         newmirrors = kzalloc(sizeof(struct raid1_info) * raid_disks * 2,
3000                              GFP_KERNEL);
3001         if (!newmirrors) {
3002                 kfree(newpoolinfo);
3003                 mempool_destroy(newpool);
3004                 return -ENOMEM;
3005         }
3006
3007         raise_barrier(conf);
3008
3009         /* ok, everything is stopped */
3010         oldpool = conf->r1bio_pool;
3011         conf->r1bio_pool = newpool;
3012
3013         for (d = d2 = 0; d < conf->raid_disks; d++) {
3014                 struct md_rdev *rdev = conf->mirrors[d].rdev;
3015                 if (rdev && rdev->raid_disk != d2) {
3016                         sysfs_unlink_rdev(mddev, rdev);
3017                         rdev->raid_disk = d2;
3018                         sysfs_unlink_rdev(mddev, rdev);
3019                         if (sysfs_link_rdev(mddev, rdev))
3020                                 printk(KERN_WARNING
3021                                        "md/raid1:%s: cannot register rd%d\n",
3022                                        mdname(mddev), rdev->raid_disk);
3023                 }
3024                 if (rdev)
3025                         newmirrors[d2++].rdev = rdev;
3026         }
3027         kfree(conf->mirrors);
3028         conf->mirrors = newmirrors;
3029         kfree(conf->poolinfo);
3030         conf->poolinfo = newpoolinfo;
3031
3032         spin_lock_irqsave(&conf->device_lock, flags);
3033         mddev->degraded += (raid_disks - conf->raid_disks);
3034         spin_unlock_irqrestore(&conf->device_lock, flags);
3035         conf->raid_disks = mddev->raid_disks = raid_disks;
3036         mddev->delta_disks = 0;
3037
3038         lower_barrier(conf);
3039
3040         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3041         md_wakeup_thread(mddev->thread);
3042
3043         mempool_destroy(oldpool);
3044         return 0;
3045 }
3046
3047 static void raid1_quiesce(struct mddev *mddev, int state)
3048 {
3049         struct r1conf *conf = mddev->private;
3050
3051         switch(state) {
3052         case 2: /* wake for suspend */
3053                 wake_up(&conf->wait_barrier);
3054                 break;
3055         case 1:
3056                 raise_barrier(conf);
3057                 break;
3058         case 0:
3059                 lower_barrier(conf);
3060                 break;
3061         }
3062 }
3063
3064 static void *raid1_takeover(struct mddev *mddev)
3065 {
3066         /* raid1 can take over:
3067          *  raid5 with 2 devices, any layout or chunk size
3068          */
3069         if (mddev->level == 5 && mddev->raid_disks == 2) {
3070                 struct r1conf *conf;
3071                 mddev->new_level = 1;
3072                 mddev->new_layout = 0;
3073                 mddev->new_chunk_sectors = 0;
3074                 conf = setup_conf(mddev);
3075                 if (!IS_ERR(conf))
3076                         conf->barrier = 1;
3077                 return conf;
3078         }
3079         return ERR_PTR(-EINVAL);
3080 }
3081
3082 static struct md_personality raid1_personality =
3083 {
3084         .name           = "raid1",
3085         .level          = 1,
3086         .owner          = THIS_MODULE,
3087         .make_request   = make_request,
3088         .run            = run,
3089         .stop           = stop,
3090         .status         = status,
3091         .error_handler  = error,
3092         .hot_add_disk   = raid1_add_disk,
3093         .hot_remove_disk= raid1_remove_disk,
3094         .spare_active   = raid1_spare_active,
3095         .sync_request   = sync_request,
3096         .resize         = raid1_resize,
3097         .size           = raid1_size,
3098         .check_reshape  = raid1_reshape,
3099         .quiesce        = raid1_quiesce,
3100         .takeover       = raid1_takeover,
3101 };
3102
3103 static int __init raid_init(void)
3104 {
3105         return register_md_personality(&raid1_personality);
3106 }
3107
3108 static void raid_exit(void)
3109 {
3110         unregister_md_personality(&raid1_personality);
3111 }
3112
3113 module_init(raid_init);
3114 module_exit(raid_exit);
3115 MODULE_LICENSE("GPL");
3116 MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
3117 MODULE_ALIAS("md-personality-3"); /* RAID1 */
3118 MODULE_ALIAS("md-raid1");
3119 MODULE_ALIAS("md-level-1");
3120
3121 module_param(max_queued_requests, int, S_IRUGO|S_IWUSR);