Pileus Git - ~andy/linux/blob - 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                 /*
 431                  * Do not set R1BIO_Uptodate if the current device is
 432                  * rebuilding or Faulty. This is because we cannot use
 433                  * such device for properly reading the data back (we could
 434                  * potentially use it, if the current write would have felt
 435                  * before rdev->recovery_offset, but for simplicity we don't
 436                  * check this here.
 437                  */
 438                 if (test_bit(In_sync, &conf->mirrors[mirror].rdev->flags) &&
 439                     !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags))
 440                         set_bit(R1BIO_Uptodate, &r1_bio->state);
 441
 442                 /* Maybe we can clear some bad blocks. */
 443                 if (is_badblock(conf->mirrors[mirror].rdev,
 444                                 r1_bio->sector, r1_bio->sectors,
 445                                 &first_bad, &bad_sectors)) {
 446                         r1_bio->bios[mirror] = IO_MADE_GOOD;
 447                         set_bit(R1BIO_MadeGood, &r1_bio->state);
 448                 }
 449         }
 450
 451         if (behind) {
 452                 if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags))
 453                         atomic_dec(&r1_bio->behind_remaining);
 454
 455                 /*
 456                  * In behind mode, we ACK the master bio once the I/O
 457                  * has safely reached all non-writemostly
 458                  * disks. Setting the Returned bit ensures that this
 459                  * gets done only once -- we don't ever want to return
 460                  * -EIO here, instead we'll wait
 461                  */
 462                 if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
 463                     test_bit(R1BIO_Uptodate, &r1_bio->state)) {
 464                         /* Maybe we can return now */
 465                         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 466                                 struct bio *mbio = r1_bio->master_bio;
 467                                 pr_debug("raid1: behind end write sectors"
 468                                          " %llu-%llu\n",
 469                                          (unsigned long long) mbio->bi_sector,
 470                                          (unsigned long long) mbio->bi_sector +
 471                                          (mbio->bi_size >> 9) - 1);
 472                                 call_bio_endio(r1_bio);
 473                         }
 474                 }
 475         }
 476         if (r1_bio->bios[mirror] == NULL)
 477                 rdev_dec_pending(conf->mirrors[mirror].rdev,
 478                                  conf->mddev);
 479
 480         /*
 481          * Let's see if all mirrored write operations have finished
 482          * already.
 483          */
 484         r1_bio_write_done(r1_bio);
 485
 486         if (to_put)
 487                 bio_put(to_put);
 488 }
 489
 490
 491 /*
 492  * This routine returns the disk from which the requested read should
 493  * be done. There is a per-array 'next expected sequential IO' sector
 494  * number - if this matches on the next IO then we use the last disk.
 495  * There is also a per-disk 'last know head position' sector that is
 496  * maintained from IRQ contexts, both the normal and the resync IO
 497  * completion handlers update this position correctly. If there is no
 498  * perfect sequential match then we pick the disk whose head is closest.
 499  *
 500  * If there are 2 mirrors in the same 2 devices, performance degrades
 501  * because position is mirror, not device based.
 502  *
 503  * The rdev for the device selected will have nr_pending incremented.
 504  */
 505 static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sectors)
 506 {
 507         const sector_t this_sector = r1_bio->sector;
 508         int sectors;
 509         int best_good_sectors;
 510         int best_disk, best_dist_disk, best_pending_disk;
 511         int has_nonrot_disk;
 512         int disk;
 513         sector_t best_dist;
 514         unsigned int min_pending;
 515         struct md_rdev *rdev;
 516         int choose_first;
 517         int choose_next_idle;
 518
 519         rcu_read_lock();
 520         /*
 521          * Check if we can balance. We can balance on the whole
 522          * device if no resync is going on, or below the resync window.
 523          * We take the first readable disk when above the resync window.
 524          */
 525  retry:
 526         sectors = r1_bio->sectors;
 527         best_disk = -1;
 528         best_dist_disk = -1;
 529         best_dist = MaxSector;
 530         best_pending_disk = -1;
 531         min_pending = UINT_MAX;
 532         best_good_sectors = 0;
 533         has_nonrot_disk = 0;
 534         choose_next_idle = 0;
 535
 536         if (conf->mddev->recovery_cp < MaxSector &&
 537             (this_sector + sectors >= conf->next_resync))
 538                 choose_first = 1;
 539         else
 540                 choose_first = 0;
 541
 542         for (disk = 0 ; disk < conf->raid_disks * 2 ; disk++) {
 543                 sector_t dist;
 544                 sector_t first_bad;
 545                 int bad_sectors;
 546                 unsigned int pending;
 547                 bool nonrot;
 548
 549                 rdev = rcu_dereference(conf->mirrors[disk].rdev);
 550                 if (r1_bio->bios[disk] == IO_BLOCKED
 551                     || rdev == NULL
 552                     || test_bit(Unmerged, &rdev->flags)
 553                     || test_bit(Faulty, &rdev->flags))
 554                         continue;
 555                 if (!test_bit(In_sync, &rdev->flags) &&
 556                     rdev->recovery_offset < this_sector + sectors)
 557                         continue;
 558                 if (test_bit(WriteMostly, &rdev->flags)) {
 559                         /* Don't balance among write-mostly, just
 560                          * use the first as a last resort */
 561                         if (best_disk < 0) {
 562                                 if (is_badblock(rdev, this_sector, sectors,
 563                                                 &first_bad, &bad_sectors)) {
 564                                         if (first_bad < this_sector)
 565                                                 /* Cannot use this */
 566                                                 continue;
 567                                         best_good_sectors = first_bad - this_sector;
 568                                 } else
 569                                         best_good_sectors = sectors;
 570                                 best_disk = disk;
 571                         }
 572                         continue;
 573                 }
 574                 /* This is a reasonable device to use.  It might
 575                  * even be best.
 576                  */
 577                 if (is_badblock(rdev, this_sector, sectors,
 578                                 &first_bad, &bad_sectors)) {
 579                         if (best_dist < MaxSector)
 580                                 /* already have a better device */
 581                                 continue;
 582                         if (first_bad <= this_sector) {
 583                                 /* cannot read here. If this is the 'primary'
 584                                  * device, then we must not read beyond
 585                                  * bad_sectors from another device..
 586                                  */
 587                                 bad_sectors -= (this_sector - first_bad);
 588                                 if (choose_first && sectors > bad_sectors)
 589                                         sectors = bad_sectors;
 590                                 if (best_good_sectors > sectors)
 591                                         best_good_sectors = sectors;
 592
 593                         } else {
 594                                 sector_t good_sectors = first_bad - this_sector;
 595                                 if (good_sectors > best_good_sectors) {
 596                                         best_good_sectors = good_sectors;
 597                                         best_disk = disk;
 598                                 }
 599                                 if (choose_first)
 600                                         break;
 601                         }
 602                         continue;
 603                 } else
 604                         best_good_sectors = sectors;
 605
 606                 nonrot = blk_queue_nonrot(bdev_get_queue(rdev->bdev));
 607                 has_nonrot_disk |= nonrot;
 608                 pending = atomic_read(&rdev->nr_pending);
 609                 dist = abs(this_sector - conf->mirrors[disk].head_position);
 610                 if (choose_first) {
 611                         best_disk = disk;
 612                         break;
 613                 }
 614                 /* Don't change to another disk for sequential reads */
 615                 if (conf->mirrors[disk].next_seq_sect == this_sector
 616                     || dist == 0) {
 617                         int opt_iosize = bdev_io_opt(rdev->bdev) >> 9;
 618                         struct raid1_info *mirror = &conf->mirrors[disk];
 619
 620                         best_disk = disk;
 621                         /*
 622                          * If buffered sequential IO size exceeds optimal
 623                          * iosize, check if there is idle disk. If yes, choose
 624                          * the idle disk. read_balance could already choose an
 625                          * idle disk before noticing it's a sequential IO in
 626                          * this disk. This doesn't matter because this disk
 627                          * will idle, next time it will be utilized after the
 628                          * first disk has IO size exceeds optimal iosize. In
 629                          * this way, iosize of the first disk will be optimal
 630                          * iosize at least. iosize of the second disk might be
 631                          * small, but not a big deal since when the second disk
 632                          * starts IO, the first disk is likely still busy.
 633                          */
 634                         if (nonrot && opt_iosize > 0 &&
 635                             mirror->seq_start != MaxSector &&
 636                             mirror->next_seq_sect > opt_iosize &&
 637                             mirror->next_seq_sect - opt_iosize >=
 638                             mirror->seq_start) {
 639                                 choose_next_idle = 1;
 640                                 continue;
 641                         }
 642                         break;
 643                 }
 644                 /* If device is idle, use it */
 645                 if (pending == 0) {
 646                         best_disk = disk;
 647                         break;
 648                 }
 649
 650                 if (choose_next_idle)
 651                         continue;
 652
 653                 if (min_pending > pending) {
 654                         min_pending = pending;
 655                         best_pending_disk = disk;
 656                 }
 657
 658                 if (dist < best_dist) {
 659                         best_dist = dist;
 660                         best_dist_disk = disk;
 661                 }
 662         }
 663
 664         /*
 665          * If all disks are rotational, choose the closest disk. If any disk is
 666          * non-rotational, choose the disk with less pending request even the
 667          * disk is rotational, which might/might not be optimal for raids with
 668          * mixed ratation/non-rotational disks depending on workload.
 669          */
 670         if (best_disk == -1) {
 671                 if (has_nonrot_disk)
 672                         best_disk = best_pending_disk;
 673                 else
 674                         best_disk = best_dist_disk;
 675         }
 676
 677         if (best_disk >= 0) {
 678                 rdev = rcu_dereference(conf->mirrors[best_disk].rdev);
 679                 if (!rdev)
 680                         goto retry;
 681                 atomic_inc(&rdev->nr_pending);
 682                 if (test_bit(Faulty, &rdev->flags)) {
 683                         /* cannot risk returning a device that failed
 684                          * before we inc'ed nr_pending
 685                          */
 686                         rdev_dec_pending(rdev, conf->mddev);
 687                         goto retry;
 688                 }
 689                 sectors = best_good_sectors;
 690
 691                 if (conf->mirrors[best_disk].next_seq_sect != this_sector)
 692                         conf->mirrors[best_disk].seq_start = this_sector;
 693
 694                 conf->mirrors[best_disk].next_seq_sect = this_sector + sectors;
 695         }
 696         rcu_read_unlock();
 697         *max_sectors = sectors;
 698
 699         return best_disk;
 700 }
 701
 702 static int raid1_mergeable_bvec(struct request_queue *q,
 703                                 struct bvec_merge_data *bvm,
 704                                 struct bio_vec *biovec)
 705 {
 706         struct mddev *mddev = q->queuedata;
 707         struct r1conf *conf = mddev->private;
 708         sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
 709         int max = biovec->bv_len;
 710
 711         if (mddev->merge_check_needed) {
 712                 int disk;
 713                 rcu_read_lock();
 714                 for (disk = 0; disk < conf->raid_disks * 2; disk++) {
 715                         struct md_rdev *rdev = rcu_dereference(
 716                                 conf->mirrors[disk].rdev);
 717                         if (rdev && !test_bit(Faulty, &rdev->flags)) {
 718                                 struct request_queue *q =
 719                                         bdev_get_queue(rdev->bdev);
 720                                 if (q->merge_bvec_fn) {
 721                                         bvm->bi_sector = sector +
 722                                                 rdev->data_offset;
 723                                         bvm->bi_bdev = rdev->bdev;
 724                                         max = min(max, q->merge_bvec_fn(
 725                                                           q, bvm, biovec));
 726                                 }
 727                         }
 728                 }
 729                 rcu_read_unlock();
 730         }
 731         return max;
 732
 733 }
 734
 735 int md_raid1_congested(struct mddev *mddev, int bits)
 736 {
 737         struct r1conf *conf = mddev->private;
 738         int i, ret = 0;
 739
 740         if ((bits & (1 << BDI_async_congested)) &&
 741             conf->pending_count >= max_queued_requests)
 742                 return 1;
 743
 744         rcu_read_lock();
 745         for (i = 0; i < conf->raid_disks * 2; i++) {
 746                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
 747                 if (rdev && !test_bit(Faulty, &rdev->flags)) {
 748                         struct request_queue *q = bdev_get_queue(rdev->bdev);
 749
 750                         BUG_ON(!q);
 751
 752                         /* Note the '|| 1' - when read_balance prefers
 753                          * non-congested targets, it can be removed
 754                          */
 755                         if ((bits & (1<<BDI_async_congested)) || 1)
 756                                 ret |= bdi_congested(&q->backing_dev_info, bits);
 757                         else
 758                                 ret &= bdi_congested(&q->backing_dev_info, bits);
 759                 }
 760         }
 761         rcu_read_unlock();
 762         return ret;
 763 }
 764 EXPORT_SYMBOL_GPL(md_raid1_congested);
 765
 766 static int raid1_congested(void *data, int bits)
 767 {
 768         struct mddev *mddev = data;
 769
 770         return mddev_congested(mddev, bits) ||
 771                 md_raid1_congested(mddev, bits);
 772 }
 773
 774 static void flush_pending_writes(struct r1conf *conf)
 775 {
 776         /* Any writes that have been queued but are awaiting
 777          * bitmap updates get flushed here.
 778          */
 779         spin_lock_irq(&conf->device_lock);
 780
 781         if (conf->pending_bio_list.head) {
 782                 struct bio *bio;
 783                 bio = bio_list_get(&conf->pending_bio_list);
 784                 conf->pending_count = 0;
 785                 spin_unlock_irq(&conf->device_lock);
 786                 /* flush any pending bitmap writes to
 787                  * disk before proceeding w/ I/O */
 788                 bitmap_unplug(conf->mddev->bitmap);
 789                 wake_up(&conf->wait_barrier);
 790
 791                 while (bio) { /* submit pending writes */
 792                         struct bio *next = bio->bi_next;
 793                         bio->bi_next = NULL;
 794                         if (unlikely((bio->bi_rw & REQ_DISCARD) &&
 795                             !blk_queue_discard(bdev_get_queue(bio->bi_bdev))))
 796                                 /* Just ignore it */
 797                                 bio_endio(bio, 0);
 798                         else
 799                                 generic_make_request(bio);
 800                         bio = next;
 801                 }
 802         } else
 803                 spin_unlock_irq(&conf->device_lock);
 804 }
 805
 806 /* Barriers....
 807  * Sometimes we need to suspend IO while we do something else,
 808  * either some resync/recovery, or reconfigure the array.
 809  * To do this we raise a 'barrier'.
 810  * The 'barrier' is a counter that can be raised multiple times
 811  * to count how many activities are happening which preclude
 812  * normal IO.
 813  * We can only raise the barrier if there is no pending IO.
 814  * i.e. if nr_pending == 0.
 815  * We choose only to raise the barrier if no-one is waiting for the
 816  * barrier to go down.  This means that as soon as an IO request
 817  * is ready, no other operations which require a barrier will start
 818  * until the IO request has had a chance.
 819  *
 820  * So: regular IO calls 'wait_barrier'.  When that returns there
 821  *    is no backgroup IO happening,  It must arrange to call
 822  *    allow_barrier when it has finished its IO.
 823  * backgroup IO calls must call raise_barrier.  Once that returns
 824  *    there is no normal IO happeing.  It must arrange to call
 825  *    lower_barrier when the particular background IO completes.
 826  */
 827 #define RESYNC_DEPTH 32
 828
 829 static void raise_barrier(struct r1conf *conf)
 830 {
 831         spin_lock_irq(&conf->resync_lock);
 832
 833         /* Wait until no block IO is waiting */
 834         wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
 835                             conf->resync_lock);
 836
 837         /* block any new IO from starting */
 838         conf->barrier++;
 839
 840         /* Now wait for all pending IO to complete */
 841         wait_event_lock_irq(conf->wait_barrier,
 842                             !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
 843                             conf->resync_lock);
 844
 845         spin_unlock_irq(&conf->resync_lock);
 846 }
 847
 848 static void lower_barrier(struct r1conf *conf)
 849 {
 850         unsigned long flags;
 851         BUG_ON(conf->barrier <= 0);
 852         spin_lock_irqsave(&conf->resync_lock, flags);
 853         conf->barrier--;
 854         spin_unlock_irqrestore(&conf->resync_lock, flags);
 855         wake_up(&conf->wait_barrier);
 856 }
 857
 858 static void wait_barrier(struct r1conf *conf)
 859 {
 860         spin_lock_irq(&conf->resync_lock);
 861         if (conf->barrier) {
 862                 conf->nr_waiting++;
 863                 /* Wait for the barrier to drop.
 864                  * However if there are already pending
 865                  * requests (preventing the barrier from
 866                  * rising completely), and the
 867                  * pre-process bio queue isn't empty,
 868                  * then don't wait, as we need to empty
 869                  * that queue to get the nr_pending
 870                  * count down.
 871                  */
 872                 wait_event_lock_irq(conf->wait_barrier,
 873                                     !conf->barrier ||
 874                                     (conf->nr_pending &&
 875                                      current->bio_list &&
 876                                      !bio_list_empty(current->bio_list)),
 877                                     conf->resync_lock);
 878                 conf->nr_waiting--;
 879         }
 880         conf->nr_pending++;
 881         spin_unlock_irq(&conf->resync_lock);
 882 }
 883
 884 static void allow_barrier(struct r1conf *conf)
 885 {
 886         unsigned long flags;
 887         spin_lock_irqsave(&conf->resync_lock, flags);
 888         conf->nr_pending--;
 889         spin_unlock_irqrestore(&conf->resync_lock, flags);
 890         wake_up(&conf->wait_barrier);
 891 }
 892
 893 static void freeze_array(struct r1conf *conf, int extra)
 894 {
 895         /* stop syncio and normal IO and wait for everything to
 896          * go quite.
 897          * We increment barrier and nr_waiting, and then
 898          * wait until nr_pending match nr_queued+extra
 899          * This is called in the context of one normal IO request
 900          * that has failed. Thus any sync request that might be pending
 901          * will be blocked by nr_pending, and we need to wait for
 902          * pending IO requests to complete or be queued for re-try.
 903          * Thus the number queued (nr_queued) plus this request (extra)
 904          * must match the number of pending IOs (nr_pending) before
 905          * we continue.
 906          */
 907         spin_lock_irq(&conf->resync_lock);
 908         conf->barrier++;
 909         conf->nr_waiting++;
 910         wait_event_lock_irq_cmd(conf->wait_barrier,
 911                                 conf->nr_pending == conf->nr_queued+extra,
 912                                 conf->resync_lock,
 913                                 flush_pending_writes(conf));
 914         spin_unlock_irq(&conf->resync_lock);
 915 }
 916 static void unfreeze_array(struct r1conf *conf)
 917 {
 918         /* reverse the effect of the freeze */
 919         spin_lock_irq(&conf->resync_lock);
 920         conf->barrier--;
 921         conf->nr_waiting--;
 922         wake_up(&conf->wait_barrier);
 923         spin_unlock_irq(&conf->resync_lock);
 924 }
 925
 926
 927 /* duplicate the data pages for behind I/O
 928  */
 929 static void alloc_behind_pages(struct bio *bio, struct r1bio *r1_bio)
 930 {
 931         int i;
 932         struct bio_vec *bvec;
 933         struct bio_vec *bvecs = kzalloc(bio->bi_vcnt * sizeof(struct bio_vec),
 934                                         GFP_NOIO);
 935         if (unlikely(!bvecs))
 936                 return;
 937
 938         bio_for_each_segment(bvec, bio, i) {
 939                 bvecs[i] = *bvec;
 940                 bvecs[i].bv_page = alloc_page(GFP_NOIO);
 941                 if (unlikely(!bvecs[i].bv_page))
 942                         goto do_sync_io;
 943                 memcpy(kmap(bvecs[i].bv_page) + bvec->bv_offset,
 944                        kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
 945                 kunmap(bvecs[i].bv_page);
 946                 kunmap(bvec->bv_page);
 947         }
 948         r1_bio->behind_bvecs = bvecs;
 949         r1_bio->behind_page_count = bio->bi_vcnt;
 950         set_bit(R1BIO_BehindIO, &r1_bio->state);
 951         return;
 952
 953 do_sync_io:
 954         for (i = 0; i < bio->bi_vcnt; i++)
 955                 if (bvecs[i].bv_page)
 956                         put_page(bvecs[i].bv_page);
 957         kfree(bvecs);
 958         pr_debug("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
 959 }
 960
 961 struct raid1_plug_cb {
 962         struct blk_plug_cb      cb;
 963         struct bio_list         pending;
 964         int                     pending_cnt;
 965 };
 966
 967 static void raid1_unplug(struct blk_plug_cb *cb, bool from_schedule)
 968 {
 969         struct raid1_plug_cb *plug = container_of(cb, struct raid1_plug_cb,
 970                                                   cb);
 971         struct mddev *mddev = plug->cb.data;
 972         struct r1conf *conf = mddev->private;
 973         struct bio *bio;
 974
 975         if (from_schedule || current->bio_list) {
 976                 spin_lock_irq(&conf->device_lock);
 977                 bio_list_merge(&conf->pending_bio_list, &plug->pending);
 978                 conf->pending_count += plug->pending_cnt;
 979                 spin_unlock_irq(&conf->device_lock);
 980                 wake_up(&conf->wait_barrier);
 981                 md_wakeup_thread(mddev->thread);
 982                 kfree(plug);
 983                 return;
 984         }
 985
 986         /* we aren't scheduling, so we can do the write-out directly. */
 987         bio = bio_list_get(&plug->pending);
 988         bitmap_unplug(mddev->bitmap);
 989         wake_up(&conf->wait_barrier);
 990
 991         while (bio) { /* submit pending writes */
 992                 struct bio *next = bio->bi_next;
 993                 bio->bi_next = NULL;
 994                 if (unlikely((bio->bi_rw & REQ_DISCARD) &&
 995                     !blk_queue_discard(bdev_get_queue(bio->bi_bdev))))
 996                         /* Just ignore it */
 997                         bio_endio(bio, 0);
 998                 else
 999                         generic_make_request(bio);
1000                 bio = next;
1001         }
1002         kfree(plug);
1003 }
1004
1005 static void make_request(struct mddev *mddev, struct bio * bio)
1006 {
1007         struct r1conf *conf = mddev->private;
1008         struct raid1_info *mirror;
1009         struct r1bio *r1_bio;
1010         struct bio *read_bio;
1011         int i, disks;
1012         struct bitmap *bitmap;
1013         unsigned long flags;
1014         const int rw = bio_data_dir(bio);
1015         const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
1016         const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA));
1017         const unsigned long do_discard = (bio->bi_rw
1018                                           & (REQ_DISCARD | REQ_SECURE));
1019         const unsigned long do_same = (bio->bi_rw & REQ_WRITE_SAME);
1020         struct md_rdev *blocked_rdev;
1021         struct blk_plug_cb *cb;
1022         struct raid1_plug_cb *plug = NULL;
1023         int first_clone;
1024         int sectors_handled;
1025         int max_sectors;
1026
1027         /*
1028          * Register the new request and wait if the reconstruction
1029          * thread has put up a bar for new requests.
1030          * Continue immediately if no resync is active currently.
1031          */
1032
1033         md_write_start(mddev, bio); /* wait on superblock update early */
1034
1035         if (bio_data_dir(bio) == WRITE &&
1036             bio->bi_sector + bio->bi_size/512 > mddev->suspend_lo &&
1037             bio->bi_sector < mddev->suspend_hi) {
1038                 /* As the suspend_* range is controlled by
1039                  * userspace, we want an interruptible
1040                  * wait.
1041                  */
1042                 DEFINE_WAIT(w);
1043                 for (;;) {
1044                         flush_signals(current);
1045                         prepare_to_wait(&conf->wait_barrier,
1046                                         &w, TASK_INTERRUPTIBLE);
1047                         if (bio->bi_sector + bio->bi_size/512 <= mddev->suspend_lo ||
1048                             bio->bi_sector >= mddev->suspend_hi)
1049                                 break;
1050                         schedule();
1051                 }
1052                 finish_wait(&conf->wait_barrier, &w);
1053         }
1054
1055         wait_barrier(conf);
1056
1057         bitmap = mddev->bitmap;
1058
1059         /*
1060          * make_request() can abort the operation when READA is being
1061          * used and no empty request is available.
1062          *
1063          */
1064         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1065
1066         r1_bio->master_bio = bio;
1067         r1_bio->sectors = bio->bi_size >> 9;
1068         r1_bio->state = 0;
1069         r1_bio->mddev = mddev;
1070         r1_bio->sector = bio->bi_sector;
1071
1072         /* We might need to issue multiple reads to different
1073          * devices if there are bad blocks around, so we keep
1074          * track of the number of reads in bio->bi_phys_segments.
1075          * If this is 0, there is only one r1_bio and no locking
1076          * will be needed when requests complete.  If it is
1077          * non-zero, then it is the number of not-completed requests.
1078          */
1079         bio->bi_phys_segments = 0;
1080         clear_bit(BIO_SEG_VALID, &bio->bi_flags);
1081
1082         if (rw == READ) {
1083                 /*
1084                  * read balancing logic:
1085                  */
1086                 int rdisk;
1087
1088 read_again:
1089                 rdisk = read_balance(conf, r1_bio, &max_sectors);
1090
1091                 if (rdisk < 0) {
1092                         /* couldn't find anywhere to read from */
1093                         raid_end_bio_io(r1_bio);
1094                         return;
1095                 }
1096                 mirror = conf->mirrors + rdisk;
1097
1098                 if (test_bit(WriteMostly, &mirror->rdev->flags) &&
1099                     bitmap) {
1100                         /* Reading from a write-mostly device must
1101                          * take care not to over-take any writes
1102                          * that are 'behind'
1103                          */
1104                         wait_event(bitmap->behind_wait,
1105                                    atomic_read(&bitmap->behind_writes) == 0);
1106                 }
1107                 r1_bio->read_disk = rdisk;
1108
1109                 read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1110                 md_trim_bio(read_bio, r1_bio->sector - bio->bi_sector,
1111                             max_sectors);
1112
1113                 r1_bio->bios[rdisk] = read_bio;
1114
1115                 read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
1116                 read_bio->bi_bdev = mirror->rdev->bdev;
1117                 read_bio->bi_end_io = raid1_end_read_request;
1118                 read_bio->bi_rw = READ | do_sync;
1119                 read_bio->bi_private = r1_bio;
1120
1121                 if (max_sectors < r1_bio->sectors) {
1122                         /* could not read all from this device, so we will
1123                          * need another r1_bio.
1124                          */
1125
1126                         sectors_handled = (r1_bio->sector + max_sectors
1127                                            - bio->bi_sector);
1128                         r1_bio->sectors = max_sectors;
1129                         spin_lock_irq(&conf->device_lock);
1130                         if (bio->bi_phys_segments == 0)
1131                                 bio->bi_phys_segments = 2;
1132                         else
1133                                 bio->bi_phys_segments++;
1134                         spin_unlock_irq(&conf->device_lock);
1135                         /* Cannot call generic_make_request directly
1136                          * as that will be queued in __make_request
1137                          * and subsequent mempool_alloc might block waiting
1138                          * for it.  So hand bio over to raid1d.
1139                          */
1140                         reschedule_retry(r1_bio);
1141
1142                         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1143
1144                         r1_bio->master_bio = bio;
1145                         r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
1146                         r1_bio->state = 0;
1147                         r1_bio->mddev = mddev;
1148                         r1_bio->sector = bio->bi_sector + sectors_handled;
1149                         goto read_again;
1150                 } else
1151                         generic_make_request(read_bio);
1152                 return;
1153         }
1154
1155         /*
1156          * WRITE:
1157          */
1158         if (conf->pending_count >= max_queued_requests) {
1159                 md_wakeup_thread(mddev->thread);
1160                 wait_event(conf->wait_barrier,
1161                            conf->pending_count < max_queued_requests);
1162         }
1163         /* first select target devices under rcu_lock and
1164          * inc refcount on their rdev.  Record them by setting
1165          * bios[x] to bio
1166          * If there are known/acknowledged bad blocks on any device on
1167          * which we have seen a write error, we want to avoid writing those
1168          * blocks.
1169          * This potentially requires several writes to write around
1170          * the bad blocks.  Each set of writes gets it's own r1bio
1171          * with a set of bios attached.
1172          */
1173
1174         disks = conf->raid_disks * 2;
1175  retry_write:
1176         blocked_rdev = NULL;
1177         rcu_read_lock();
1178         max_sectors = r1_bio->sectors;
1179         for (i = 0;  i < disks; i++) {
1180                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1181                 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
1182                         atomic_inc(&rdev->nr_pending);
1183                         blocked_rdev = rdev;
1184                         break;
1185                 }
1186                 r1_bio->bios[i] = NULL;
1187                 if (!rdev || test_bit(Faulty, &rdev->flags)
1188                     || test_bit(Unmerged, &rdev->flags)) {
1189                         if (i < conf->raid_disks)
1190                                 set_bit(R1BIO_Degraded, &r1_bio->state);
1191                         continue;
1192                 }
1193
1194                 atomic_inc(&rdev->nr_pending);
1195                 if (test_bit(WriteErrorSeen, &rdev->flags)) {
1196                         sector_t first_bad;
1197                         int bad_sectors;
1198                         int is_bad;
1199
1200                         is_bad = is_badblock(rdev, r1_bio->sector,
1201                                              max_sectors,
1202                                              &first_bad, &bad_sectors);
1203                         if (is_bad < 0) {
1204                                 /* mustn't write here until the bad block is
1205                                  * acknowledged*/
1206                                 set_bit(BlockedBadBlocks, &rdev->flags);
1207                                 blocked_rdev = rdev;
1208                                 break;
1209                         }
1210                         if (is_bad && first_bad <= r1_bio->sector) {
1211                                 /* Cannot write here at all */
1212                                 bad_sectors -= (r1_bio->sector - first_bad);
1213                                 if (bad_sectors < max_sectors)
1214                                         /* mustn't write more than bad_sectors
1215                                          * to other devices yet
1216                                          */
1217                                         max_sectors = bad_sectors;
1218                                 rdev_dec_pending(rdev, mddev);
1219                                 /* We don't set R1BIO_Degraded as that
1220                                  * only applies if the disk is
1221                                  * missing, so it might be re-added,
1222                                  * and we want to know to recover this
1223                                  * chunk.
1224                                  * In this case the device is here,
1225                                  * and the fact that this chunk is not
1226                                  * in-sync is recorded in the bad
1227                                  * block log
1228                                  */
1229                                 continue;
1230                         }
1231                         if (is_bad) {
1232                                 int good_sectors = first_bad - r1_bio->sector;
1233                                 if (good_sectors < max_sectors)
1234                                         max_sectors = good_sectors;
1235                         }
1236                 }
1237                 r1_bio->bios[i] = bio;
1238         }
1239         rcu_read_unlock();
1240
1241         if (unlikely(blocked_rdev)) {
1242                 /* Wait for this device to become unblocked */
1243                 int j;
1244
1245                 for (j = 0; j < i; j++)
1246                         if (r1_bio->bios[j])
1247                                 rdev_dec_pending(conf->mirrors[j].rdev, mddev);
1248                 r1_bio->state = 0;
1249                 allow_barrier(conf);
1250                 md_wait_for_blocked_rdev(blocked_rdev, mddev);
1251                 wait_barrier(conf);
1252                 goto retry_write;
1253         }
1254
1255         if (max_sectors < r1_bio->sectors) {
1256                 /* We are splitting this write into multiple parts, so
1257                  * we need to prepare for allocating another r1_bio.
1258                  */
1259                 r1_bio->sectors = max_sectors;
1260                 spin_lock_irq(&conf->device_lock);
1261                 if (bio->bi_phys_segments == 0)
1262                         bio->bi_phys_segments = 2;
1263                 else
1264                         bio->bi_phys_segments++;
1265                 spin_unlock_irq(&conf->device_lock);
1266         }
1267         sectors_handled = r1_bio->sector + max_sectors - bio->bi_sector;
1268
1269         atomic_set(&r1_bio->remaining, 1);
1270         atomic_set(&r1_bio->behind_remaining, 0);
1271
1272         first_clone = 1;
1273         for (i = 0; i < disks; i++) {
1274                 struct bio *mbio;
1275                 if (!r1_bio->bios[i])
1276                         continue;
1277
1278                 mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1279                 md_trim_bio(mbio, r1_bio->sector - bio->bi_sector, max_sectors);
1280
1281                 if (first_clone) {
1282                         /* do behind I/O ?
1283                          * Not if there are too many, or cannot
1284                          * allocate memory, or a reader on WriteMostly
1285                          * is waiting for behind writes to flush */
1286                         if (bitmap &&
1287                             (atomic_read(&bitmap->behind_writes)
1288                              < mddev->bitmap_info.max_write_behind) &&
1289                             !waitqueue_active(&bitmap->behind_wait))
1290                                 alloc_behind_pages(mbio, r1_bio);
1291
1292                         bitmap_startwrite(bitmap, r1_bio->sector,
1293                                           r1_bio->sectors,
1294                                           test_bit(R1BIO_BehindIO,
1295                                                    &r1_bio->state));
1296                         first_clone = 0;
1297                 }
1298                 if (r1_bio->behind_bvecs) {
1299                         struct bio_vec *bvec;
1300                         int j;
1301
1302                         /* Yes, I really want the '__' version so that
1303                          * we clear any unused pointer in the io_vec, rather
1304                          * than leave them unchanged.  This is important
1305                          * because when we come to free the pages, we won't
1306                          * know the original bi_idx, so we just free
1307                          * them all
1308                          */
1309                         __bio_for_each_segment(bvec, mbio, j, 0)
1310                                 bvec->bv_page = r1_bio->behind_bvecs[j].bv_page;
1311                         if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
1312                                 atomic_inc(&r1_bio->behind_remaining);
1313                 }
1314
1315                 r1_bio->bios[i] = mbio;
1316
1317                 mbio->bi_sector = (r1_bio->sector +
1318                                    conf->mirrors[i].rdev->data_offset);
1319                 mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1320                 mbio->bi_end_io = raid1_end_write_request;
1321                 mbio->bi_rw =
1322                         WRITE | do_flush_fua | do_sync | do_discard | do_same;
1323                 mbio->bi_private = r1_bio;
1324
1325                 atomic_inc(&r1_bio->remaining);
1326
1327                 cb = blk_check_plugged(raid1_unplug, mddev, sizeof(*plug));
1328                 if (cb)
1329                         plug = container_of(cb, struct raid1_plug_cb, cb);
1330                 else
1331                         plug = NULL;
1332                 spin_lock_irqsave(&conf->device_lock, flags);
1333                 if (plug) {
1334                         bio_list_add(&plug->pending, mbio);
1335                         plug->pending_cnt++;
1336                 } else {
1337                         bio_list_add(&conf->pending_bio_list, mbio);
1338                         conf->pending_count++;
1339                 }
1340                 spin_unlock_irqrestore(&conf->device_lock, flags);
1341                 if (!plug)
1342                         md_wakeup_thread(mddev->thread);
1343         }
1344         /* Mustn't call r1_bio_write_done before this next test,
1345          * as it could result in the bio being freed.
1346          */
1347         if (sectors_handled < (bio->bi_size >> 9)) {
1348                 r1_bio_write_done(r1_bio);
1349                 /* We need another r1_bio.  It has already been counted
1350                  * in bio->bi_phys_segments
1351                  */
1352                 r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1353                 r1_bio->master_bio = bio;
1354                 r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
1355                 r1_bio->state = 0;
1356                 r1_bio->mddev = mddev;
1357                 r1_bio->sector = bio->bi_sector + sectors_handled;
1358                 goto retry_write;
1359         }
1360
1361         r1_bio_write_done(r1_bio);
1362
1363         /* In case raid1d snuck in to freeze_array */
1364         wake_up(&conf->wait_barrier);
1365 }
1366
1367 static void status(struct seq_file *seq, struct mddev *mddev)
1368 {
1369         struct r1conf *conf = mddev->private;
1370         int i;
1371
1372         seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1373                    conf->raid_disks - mddev->degraded);
1374         rcu_read_lock();
1375         for (i = 0; i < conf->raid_disks; i++) {
1376                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1377                 seq_printf(seq, "%s",
1378                            rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1379         }
1380         rcu_read_unlock();
1381         seq_printf(seq, "]");
1382 }
1383
1384
1385 static void error(struct mddev *mddev, struct md_rdev *rdev)
1386 {
1387         char b[BDEVNAME_SIZE];
1388         struct r1conf *conf = mddev->private;
1389
1390         /*
1391          * If it is not operational, then we have already marked it as dead
1392          * else if it is the last working disks, ignore the error, let the
1393          * next level up know.
1394          * else mark the drive as failed
1395          */
1396         if (test_bit(In_sync, &rdev->flags)
1397             && (conf->raid_disks - mddev->degraded) == 1) {
1398                 /*
1399                  * Don't fail the drive, act as though we were just a
1400                  * normal single drive.
1401                  * However don't try a recovery from this drive as
1402                  * it is very likely to fail.
1403                  */
1404                 conf->recovery_disabled = mddev->recovery_disabled;
1405                 return;
1406         }
1407         set_bit(Blocked, &rdev->flags);
1408         if (test_and_clear_bit(In_sync, &rdev->flags)) {
1409                 unsigned long flags;
1410                 spin_lock_irqsave(&conf->device_lock, flags);
1411                 mddev->degraded++;
1412                 set_bit(Faulty, &rdev->flags);
1413                 spin_unlock_irqrestore(&conf->device_lock, flags);
1414                 /*
1415                  * if recovery is running, make sure it aborts.
1416                  */
1417                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1418         } else
1419                 set_bit(Faulty, &rdev->flags);
1420         set_bit(MD_CHANGE_DEVS, &mddev->flags);
1421         printk(KERN_ALERT
1422                "md/raid1:%s: Disk failure on %s, disabling device.\n"
1423                "md/raid1:%s: Operation continuing on %d devices.\n",
1424                mdname(mddev), bdevname(rdev->bdev, b),
1425                mdname(mddev), conf->raid_disks - mddev->degraded);
1426 }
1427
1428 static void print_conf(struct r1conf *conf)
1429 {
1430         int i;
1431
1432         printk(KERN_DEBUG "RAID1 conf printout:\n");
1433         if (!conf) {
1434                 printk(KERN_DEBUG "(!conf)\n");
1435                 return;
1436         }
1437         printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1438                 conf->raid_disks);
1439
1440         rcu_read_lock();
1441         for (i = 0; i < conf->raid_disks; i++) {
1442                 char b[BDEVNAME_SIZE];
1443                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1444                 if (rdev)
1445                         printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
1446                                i, !test_bit(In_sync, &rdev->flags),
1447                                !test_bit(Faulty, &rdev->flags),
1448                                bdevname(rdev->bdev,b));
1449         }
1450         rcu_read_unlock();
1451 }
1452
1453 static void close_sync(struct r1conf *conf)
1454 {
1455         wait_barrier(conf);
1456         allow_barrier(conf);
1457
1458         mempool_destroy(conf->r1buf_pool);
1459         conf->r1buf_pool = NULL;
1460 }
1461
1462 static int raid1_spare_active(struct mddev *mddev)
1463 {
1464         int i;
1465         struct r1conf *conf = mddev->private;
1466         int count = 0;
1467         unsigned long flags;
1468
1469         /*
1470          * Find all failed disks within the RAID1 configuration
1471          * and mark them readable.
1472          * Called under mddev lock, so rcu protection not needed.
1473          */
1474         for (i = 0; i < conf->raid_disks; i++) {
1475                 struct md_rdev *rdev = conf->mirrors[i].rdev;
1476                 struct md_rdev *repl = conf->mirrors[conf->raid_disks + i].rdev;
1477                 if (repl
1478                     && repl->recovery_offset == MaxSector
1479                     && !test_bit(Faulty, &repl->flags)
1480                     && !test_and_set_bit(In_sync, &repl->flags)) {
1481                         /* replacement has just become active */
1482                         if (!rdev ||
1483                             !test_and_clear_bit(In_sync, &rdev->flags))
1484                                 count++;
1485                         if (rdev) {
1486                                 /* Replaced device not technically
1487                                  * faulty, but we need to be sure
1488                                  * it gets removed and never re-added
1489                                  */
1490                                 set_bit(Faulty, &rdev->flags);
1491                                 sysfs_notify_dirent_safe(
1492                                         rdev->sysfs_state);
1493                         }
1494                 }
1495                 if (rdev
1496                     && !test_bit(Faulty, &rdev->flags)
1497                     && !test_and_set_bit(In_sync, &rdev->flags)) {
1498                         count++;
1499                         sysfs_notify_dirent_safe(rdev->sysfs_state);
1500                 }
1501         }
1502         spin_lock_irqsave(&conf->device_lock, flags);
1503         mddev->degraded -= count;
1504         spin_unlock_irqrestore(&conf->device_lock, flags);
1505
1506         print_conf(conf);
1507         return count;
1508 }
1509
1510
1511 static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
1512 {
1513         struct r1conf *conf = mddev->private;
1514         int err = -EEXIST;
1515         int mirror = 0;
1516         struct raid1_info *p;
1517         int first = 0;
1518         int last = conf->raid_disks - 1;
1519         struct request_queue *q = bdev_get_queue(rdev->bdev);
1520
1521         if (mddev->recovery_disabled == conf->recovery_disabled)
1522                 return -EBUSY;
1523
1524         if (rdev->raid_disk >= 0)
1525                 first = last = rdev->raid_disk;
1526
1527         if (q->merge_bvec_fn) {
1528                 set_bit(Unmerged, &rdev->flags);
1529                 mddev->merge_check_needed = 1;
1530         }
1531
1532         for (mirror = first; mirror <= last; mirror++) {
1533                 p = conf->mirrors+mirror;
1534                 if (!p->rdev) {
1535
1536                         disk_stack_limits(mddev->gendisk, rdev->bdev,
1537                                           rdev->data_offset << 9);
1538
1539                         p->head_position = 0;
1540                         rdev->raid_disk = mirror;
1541                         err = 0;
1542                         /* As all devices are equivalent, we don't need a full recovery
1543                          * if this was recently any drive of the array
1544                          */
1545                         if (rdev->saved_raid_disk < 0)
1546                                 conf->fullsync = 1;
1547                         rcu_assign_pointer(p->rdev, rdev);
1548                         break;
1549                 }
1550                 if (test_bit(WantReplacement, &p->rdev->flags) &&
1551                     p[conf->raid_disks].rdev == NULL) {
1552                         /* Add this device as a replacement */
1553                         clear_bit(In_sync, &rdev->flags);
1554                         set_bit(Replacement, &rdev->flags);
1555                         rdev->raid_disk = mirror;
1556                         err = 0;
1557                         conf->fullsync = 1;
1558                         rcu_assign_pointer(p[conf->raid_disks].rdev, rdev);
1559                         break;
1560                 }
1561         }
1562         if (err == 0 && test_bit(Unmerged, &rdev->flags)) {
1563                 /* Some requests might not have seen this new
1564                  * merge_bvec_fn.  We must wait for them to complete
1565                  * before merging the device fully.
1566                  * First we make sure any code which has tested
1567                  * our function has submitted the request, then
1568                  * we wait for all outstanding requests to complete.
1569                  */
1570                 synchronize_sched();
1571                 freeze_array(conf, 0);
1572                 unfreeze_array(conf);
1573                 clear_bit(Unmerged, &rdev->flags);
1574         }
1575         md_integrity_add_rdev(rdev, mddev);
1576         if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
1577                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
1578         print_conf(conf);
1579         return err;
1580 }
1581
1582 static int raid1_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
1583 {
1584         struct r1conf *conf = mddev->private;
1585         int err = 0;
1586         int number = rdev->raid_disk;
1587         struct raid1_info *p = conf->mirrors + number;
1588
1589         if (rdev != p->rdev)
1590                 p = conf->mirrors + conf->raid_disks + number;
1591
1592         print_conf(conf);
1593         if (rdev == p->rdev) {
1594                 if (test_bit(In_sync, &rdev->flags) ||
1595                     atomic_read(&rdev->nr_pending)) {
1596                         err = -EBUSY;
1597                         goto abort;
1598                 }
1599                 /* Only remove non-faulty devices if recovery
1600                  * is not possible.
1601                  */
1602                 if (!test_bit(Faulty, &rdev->flags) &&
1603                     mddev->recovery_disabled != conf->recovery_disabled &&
1604                     mddev->degraded < conf->raid_disks) {
1605                         err = -EBUSY;
1606                         goto abort;
1607                 }
1608                 p->rdev = NULL;
1609                 synchronize_rcu();
1610                 if (atomic_read(&rdev->nr_pending)) {
1611                         /* lost the race, try later */
1612                         err = -EBUSY;
1613                         p->rdev = rdev;
1614                         goto abort;
1615                 } else if (conf->mirrors[conf->raid_disks + number].rdev) {
1616                         /* We just removed a device that is being replaced.
1617                          * Move down the replacement.  We drain all IO before
1618                          * doing this to avoid confusion.
1619                          */
1620                         struct md_rdev *repl =
1621                                 conf->mirrors[conf->raid_disks + number].rdev;
1622                         freeze_array(conf, 0);
1623                         clear_bit(Replacement, &repl->flags);
1624                         p->rdev = repl;
1625                         conf->mirrors[conf->raid_disks + number].rdev = NULL;
1626                         unfreeze_array(conf);
1627                         clear_bit(WantReplacement, &rdev->flags);
1628                 } else
1629                         clear_bit(WantReplacement, &rdev->flags);
1630                 err = md_integrity_register(mddev);
1631         }
1632 abort:
1633
1634         print_conf(conf);
1635         return err;
1636 }
1637
1638
1639 static void end_sync_read(struct bio *bio, int error)
1640 {
1641         struct r1bio *r1_bio = bio->bi_private;
1642
1643         update_head_pos(r1_bio->read_disk, r1_bio);
1644
1645         /*
1646          * we have read a block, now it needs to be re-written,
1647          * or re-read if the read failed.
1648          * We don't do much here, just schedule handling by raid1d
1649          */
1650         if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1651                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1652
1653         if (atomic_dec_and_test(&r1_bio->remaining))
1654                 reschedule_retry(r1_bio);
1655 }
1656
1657 static void end_sync_write(struct bio *bio, int error)
1658 {
1659         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1660         struct r1bio *r1_bio = bio->bi_private;
1661         struct mddev *mddev = r1_bio->mddev;
1662         struct r1conf *conf = mddev->private;
1663         int mirror=0;
1664         sector_t first_bad;
1665         int bad_sectors;
1666
1667         mirror = find_bio_disk(r1_bio, bio);
1668
1669         if (!uptodate) {
1670                 sector_t sync_blocks = 0;
1671                 sector_t s = r1_bio->sector;
1672                 long sectors_to_go = r1_bio->sectors;
1673                 /* make sure these bits doesn't get cleared. */
1674                 do {
1675                         bitmap_end_sync(mddev->bitmap, s,
1676                                         &sync_blocks, 1);
1677                         s += sync_blocks;
1678                         sectors_to_go -= sync_blocks;
1679                 } while (sectors_to_go > 0);
1680                 set_bit(WriteErrorSeen,
1681                         &conf->mirrors[mirror].rdev->flags);
1682                 if (!test_and_set_bit(WantReplacement,
1683                                       &conf->mirrors[mirror].rdev->flags))
1684                         set_bit(MD_RECOVERY_NEEDED, &
1685                                 mddev->recovery);
1686                 set_bit(R1BIO_WriteError, &r1_bio->state);
1687         } else if (is_badblock(conf->mirrors[mirror].rdev,
1688                                r1_bio->sector,
1689                                r1_bio->sectors,
1690                                &first_bad, &bad_sectors) &&
1691                    !is_badblock(conf->mirrors[r1_bio->read_disk].rdev,
1692                                 r1_bio->sector,
1693                                 r1_bio->sectors,
1694                                 &first_bad, &bad_sectors)
1695                 )
1696                 set_bit(R1BIO_MadeGood, &r1_bio->state);
1697
1698         if (atomic_dec_and_test(&r1_bio->remaining)) {
1699                 int s = r1_bio->sectors;
1700                 if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
1701                     test_bit(R1BIO_WriteError, &r1_bio->state))
1702                         reschedule_retry(r1_bio);
1703                 else {
1704                         put_buf(r1_bio);
1705                         md_done_sync(mddev, s, uptodate);
1706                 }
1707         }
1708 }
1709
1710 static int r1_sync_page_io(struct md_rdev *rdev, sector_t sector,
1711                             int sectors, struct page *page, int rw)
1712 {
1713         if (sync_page_io(rdev, sector, sectors << 9, page, rw, false))
1714                 /* success */
1715                 return 1;
1716         if (rw == WRITE) {
1717                 set_bit(WriteErrorSeen, &rdev->flags);
1718                 if (!test_and_set_bit(WantReplacement,
1719                                       &rdev->flags))
1720                         set_bit(MD_RECOVERY_NEEDED, &
1721                                 rdev->mddev->recovery);
1722         }
1723         /* need to record an error - either for the block or the device */
1724         if (!rdev_set_badblocks(rdev, sector, sectors, 0))
1725                 md_error(rdev->mddev, rdev);
1726         return 0;
1727 }
1728
1729 static int fix_sync_read_error(struct r1bio *r1_bio)
1730 {
1731         /* Try some synchronous reads of other devices to get
1732          * good data, much like with normal read errors.  Only
1733          * read into the pages we already have so we don't
1734          * need to re-issue the read request.
1735          * We don't need to freeze the array, because being in an
1736          * active sync request, there is no normal IO, and
1737          * no overlapping syncs.
1738          * We don't need to check is_badblock() again as we
1739          * made sure that anything with a bad block in range
1740          * will have bi_end_io clear.
1741          */
1742         struct mddev *mddev = r1_bio->mddev;
1743         struct r1conf *conf = mddev->private;
1744         struct bio *bio = r1_bio->bios[r1_bio->read_disk];
1745         sector_t sect = r1_bio->sector;
1746         int sectors = r1_bio->sectors;
1747         int idx = 0;
1748
1749         while(sectors) {
1750                 int s = sectors;
1751                 int d = r1_bio->read_disk;
1752                 int success = 0;
1753                 struct md_rdev *rdev;
1754                 int start;
1755
1756                 if (s > (PAGE_SIZE>>9))
1757                         s = PAGE_SIZE >> 9;
1758                 do {
1759                         if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1760                                 /* No rcu protection needed here devices
1761                                  * can only be removed when no resync is
1762                                  * active, and resync is currently active
1763                                  */
1764                                 rdev = conf->mirrors[d].rdev;
1765                                 if (sync_page_io(rdev, sect, s<<9,
1766                                                  bio->bi_io_vec[idx].bv_page,
1767                                                  READ, false)) {
1768                                         success = 1;
1769                                         break;
1770                                 }
1771                         }
1772                         d++;
1773                         if (d == conf->raid_disks * 2)
1774                                 d = 0;
1775                 } while (!success && d != r1_bio->read_disk);
1776
1777                 if (!success) {
1778                         char b[BDEVNAME_SIZE];
1779                         int abort = 0;
1780                         /* Cannot read from anywhere, this block is lost.
1781                          * Record a bad block on each device.  If that doesn't
1782                          * work just disable and interrupt the recovery.
1783                          * Don't fail devices as that won't really help.
1784                          */
1785                         printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O read error"
1786                                " for block %llu\n",
1787                                mdname(mddev),
1788                                bdevname(bio->bi_bdev, b),
1789                                (unsigned long long)r1_bio->sector);
1790                         for (d = 0; d < conf->raid_disks * 2; d++) {
1791                                 rdev = conf->mirrors[d].rdev;
1792                                 if (!rdev || test_bit(Faulty, &rdev->flags))
1793                                         continue;
1794                                 if (!rdev_set_badblocks(rdev, sect, s, 0))
1795                                         abort = 1;
1796                         }
1797                         if (abort) {
1798                                 conf->recovery_disabled =
1799                                         mddev->recovery_disabled;
1800                                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1801                                 md_done_sync(mddev, r1_bio->sectors, 0);
1802                                 put_buf(r1_bio);
1803                                 return 0;
1804                         }
1805                         /* Try next page */
1806                         sectors -= s;
1807                         sect += s;
1808                         idx++;
1809                         continue;
1810                 }
1811
1812                 start = d;
1813                 /* write it back and re-read */
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                                             WRITE) == 0) {
1824                                 r1_bio->bios[d]->bi_end_io = NULL;
1825                                 rdev_dec_pending(rdev, mddev);
1826                         }
1827                 }
1828                 d = start;
1829                 while (d != r1_bio->read_disk) {
1830                         if (d == 0)
1831                                 d = conf->raid_disks * 2;
1832                         d--;
1833                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1834                                 continue;
1835                         rdev = conf->mirrors[d].rdev;
1836                         if (r1_sync_page_io(rdev, sect, s,
1837                                             bio->bi_io_vec[idx].bv_page,
1838                                             READ) != 0)
1839                                 atomic_add(s, &rdev->corrected_errors);
1840                 }
1841                 sectors -= s;
1842                 sect += s;
1843                 idx ++;
1844         }
1845         set_bit(R1BIO_Uptodate, &r1_bio->state);
1846         set_bit(BIO_UPTODATE, &bio->bi_flags);
1847         return 1;
1848 }
1849
1850 static int process_checks(struct r1bio *r1_bio)
1851 {
1852         /* We have read all readable devices.  If we haven't
1853          * got the block, then there is no hope left.
1854          * If we have, then we want to do a comparison
1855          * and skip the write if everything is the same.
1856          * If any blocks failed to read, then we need to
1857          * attempt an over-write
1858          */
1859         struct mddev *mddev = r1_bio->mddev;
1860         struct r1conf *conf = mddev->private;
1861         int primary;
1862         int i;
1863         int vcnt;
1864
1865         for (primary = 0; primary < conf->raid_disks * 2; primary++)
1866                 if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1867                     test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
1868                         r1_bio->bios[primary]->bi_end_io = NULL;
1869                         rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1870                         break;
1871                 }
1872         r1_bio->read_disk = primary;
1873         vcnt = (r1_bio->sectors + PAGE_SIZE / 512 - 1) >> (PAGE_SHIFT - 9);
1874         for (i = 0; i < conf->raid_disks * 2; i++) {
1875                 int j;
1876                 struct bio *pbio = r1_bio->bios[primary];
1877                 struct bio *sbio = r1_bio->bios[i];
1878                 int size;
1879
1880                 if (r1_bio->bios[i]->bi_end_io != end_sync_read)
1881                         continue;
1882
1883                 if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
1884                         for (j = vcnt; j-- ; ) {
1885                                 struct page *p, *s;
1886                                 p = pbio->bi_io_vec[j].bv_page;
1887                                 s = sbio->bi_io_vec[j].bv_page;
1888                                 if (memcmp(page_address(p),
1889                                            page_address(s),
1890                                            sbio->bi_io_vec[j].bv_len))
1891                                         break;
1892                         }
1893                 } else
1894                         j = 0;
1895                 if (j >= 0)
1896                         atomic64_add(r1_bio->sectors, &mddev->resync_mismatches);
1897                 if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
1898                               && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
1899                         /* No need to write to this device. */
1900                         sbio->bi_end_io = NULL;
1901                         rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1902                         continue;
1903                 }
1904                 /* fixup the bio for reuse */
1905                 sbio->bi_vcnt = vcnt;
1906                 sbio->bi_size = r1_bio->sectors << 9;
1907                 sbio->bi_idx = 0;
1908                 sbio->bi_phys_segments = 0;
1909                 sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1910                 sbio->bi_flags |= 1 << BIO_UPTODATE;
1911                 sbio->bi_next = NULL;
1912                 sbio->bi_sector = r1_bio->sector +
1913                         conf->mirrors[i].rdev->data_offset;
1914                 sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1915                 size = sbio->bi_size;
1916                 for (j = 0; j < vcnt ; j++) {
1917                         struct bio_vec *bi;
1918                         bi = &sbio->bi_io_vec[j];
1919                         bi->bv_offset = 0;
1920                         if (size > PAGE_SIZE)
1921                                 bi->bv_len = PAGE_SIZE;
1922                         else
1923                                 bi->bv_len = size;
1924                         size -= PAGE_SIZE;
1925                         memcpy(page_address(bi->bv_page),
1926                                page_address(pbio->bi_io_vec[j].bv_page),
1927                                PAGE_SIZE);
1928                 }
1929         }
1930         return 0;
1931 }
1932
1933 static void sync_request_write(struct mddev *mddev, struct r1bio *r1_bio)
1934 {
1935         struct r1conf *conf = mddev->private;
1936         int i;
1937         int disks = conf->raid_disks * 2;
1938         struct bio *bio, *wbio;
1939
1940         bio = r1_bio->bios[r1_bio->read_disk];
1941
1942         if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
1943                 /* ouch - failed to read all of that. */
1944                 if (!fix_sync_read_error(r1_bio))
1945                         return;
1946
1947         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1948                 if (process_checks(r1_bio) < 0)
1949                         return;
1950         /*
1951          * schedule writes
1952          */
1953         atomic_set(&r1_bio->remaining, 1);
1954         for (i = 0; i < disks ; i++) {
1955                 wbio = r1_bio->bios[i];
1956                 if (wbio->bi_end_io == NULL ||
1957                     (wbio->bi_end_io == end_sync_read &&
1958                      (i == r1_bio->read_disk ||
1959                       !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
1960                         continue;
1961
1962                 wbio->bi_rw = WRITE;
1963                 wbio->bi_end_io = end_sync_write;
1964                 atomic_inc(&r1_bio->remaining);
1965                 md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1966
1967                 generic_make_request(wbio);
1968         }
1969
1970         if (atomic_dec_and_test(&r1_bio->remaining)) {
1971                 /* if we're here, all write(s) have completed, so clean up */
1972                 int s = r1_bio->sectors;
1973                 if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
1974                     test_bit(R1BIO_WriteError, &r1_bio->state))
1975                         reschedule_retry(r1_bio);
1976                 else {
1977                         put_buf(r1_bio);
1978                         md_done_sync(mddev, s, 1);
1979                 }
1980         }
1981 }
1982
1983 /*
1984  * This is a kernel thread which:
1985  *
1986  *      1.      Retries failed read operations on working mirrors.
1987  *      2.      Updates the raid superblock when problems encounter.
1988  *      3.      Performs writes following reads for array synchronising.
1989  */
1990
1991 static void fix_read_error(struct r1conf *conf, int read_disk,
1992                            sector_t sect, int sectors)
1993 {
1994         struct mddev *mddev = conf->mddev;
1995         while(sectors) {
1996                 int s = sectors;
1997                 int d = read_disk;
1998                 int success = 0;
1999                 int start;
2000                 struct md_rdev *rdev;
2001
2002                 if (s > (PAGE_SIZE>>9))
2003                         s = PAGE_SIZE >> 9;
2004
2005                 do {
2006                         /* Note: no rcu protection needed here
2007                          * as this is synchronous in the raid1d thread
2008                          * which is the thread that might remove
2009                          * a device.  If raid1d ever becomes multi-threaded....
2010                          */
2011                         sector_t first_bad;
2012                         int bad_sectors;
2013
2014                         rdev = conf->mirrors[d].rdev;
2015                         if (rdev &&
2016                             (test_bit(In_sync, &rdev->flags) ||
2017                              (!test_bit(Faulty, &rdev->flags) &&
2018                               rdev->recovery_offset >= sect + s)) &&
2019                             is_badblock(rdev, sect, s,
2020                                         &first_bad, &bad_sectors) == 0 &&
2021                             sync_page_io(rdev, sect, s<<9,
2022                                          conf->tmppage, READ, false))
2023                                 success = 1;
2024                         else {
2025                                 d++;
2026                                 if (d == conf->raid_disks * 2)
2027                                         d = 0;
2028                         }
2029                 } while (!success && d != read_disk);
2030
2031                 if (!success) {
2032                         /* Cannot read from anywhere - mark it bad */
2033                         struct md_rdev *rdev = conf->mirrors[read_disk].rdev;
2034                         if (!rdev_set_badblocks(rdev, sect, s, 0))
2035                                 md_error(mddev, rdev);
2036                         break;
2037                 }
2038                 /* write it back and re-read */
2039                 start = d;
2040                 while (d != read_disk) {
2041                         if (d==0)
2042                                 d = conf->raid_disks * 2;
2043                         d--;
2044                         rdev = conf->mirrors[d].rdev;
2045                         if (rdev &&
2046                             test_bit(In_sync, &rdev->flags))
2047                                 r1_sync_page_io(rdev, sect, s,
2048                                                 conf->tmppage, WRITE);
2049                 }
2050                 d = start;
2051                 while (d != read_disk) {
2052                         char b[BDEVNAME_SIZE];
2053                         if (d==0)
2054                                 d = conf->raid_disks * 2;
2055                         d--;
2056                         rdev = conf->mirrors[d].rdev;
2057                         if (rdev &&
2058                             test_bit(In_sync, &rdev->flags)) {
2059                                 if (r1_sync_page_io(rdev, sect, s,
2060                                                     conf->tmppage, READ)) {
2061                                         atomic_add(s, &rdev->corrected_errors);
2062                                         printk(KERN_INFO
2063                                                "md/raid1:%s: read error corrected "
2064                                                "(%d sectors at %llu on %s)\n",
2065                                                mdname(mddev), s,
2066                                                (unsigned long long)(sect +
2067                                                    rdev->data_offset),
2068                                                bdevname(rdev->bdev, b));
2069                                 }
2070                         }
2071                 }
2072                 sectors -= s;
2073                 sect += s;
2074         }
2075 }
2076
2077 static void bi_complete(struct bio *bio, int error)
2078 {
2079         complete((struct completion *)bio->bi_private);
2080 }
2081
2082 static int submit_bio_wait(int rw, struct bio *bio)
2083 {
2084         struct completion event;
2085         rw |= REQ_SYNC;
2086
2087         init_completion(&event);
2088         bio->bi_private = &event;
2089         bio->bi_end_io = bi_complete;
2090         submit_bio(rw, bio);
2091         wait_for_completion(&event);
2092
2093         return test_bit(BIO_UPTODATE, &bio->bi_flags);
2094 }
2095
2096 static int narrow_write_error(struct r1bio *r1_bio, int i)
2097 {
2098         struct mddev *mddev = r1_bio->mddev;
2099         struct r1conf *conf = mddev->private;
2100         struct md_rdev *rdev = conf->mirrors[i].rdev;
2101         int vcnt, idx;
2102         struct bio_vec *vec;
2103
2104         /* bio has the data to be written to device 'i' where
2105          * we just recently had a write error.
2106          * We repeatedly clone the bio and trim down to one block,
2107          * then try the write.  Where the write fails we record
2108          * a bad block.
2109          * It is conceivable that the bio doesn't exactly align with
2110          * blocks.  We must handle this somehow.
2111          *
2112          * We currently own a reference on the rdev.
2113          */
2114
2115         int block_sectors;
2116         sector_t sector;
2117         int sectors;
2118         int sect_to_write = r1_bio->sectors;
2119         int ok = 1;
2120
2121         if (rdev->badblocks.shift < 0)
2122                 return 0;
2123
2124         block_sectors = 1 << rdev->badblocks.shift;
2125         sector = r1_bio->sector;
2126         sectors = ((sector + block_sectors)
2127                    & ~(sector_t)(block_sectors - 1))
2128                 - sector;
2129
2130         if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
2131                 vcnt = r1_bio->behind_page_count;
2132                 vec = r1_bio->behind_bvecs;
2133                 idx = 0;
2134                 while (vec[idx].bv_page == NULL)
2135                         idx++;
2136         } else {
2137                 vcnt = r1_bio->master_bio->bi_vcnt;
2138                 vec = r1_bio->master_bio->bi_io_vec;
2139                 idx = r1_bio->master_bio->bi_idx;
2140         }
2141         while (sect_to_write) {
2142                 struct bio *wbio;
2143                 if (sectors > sect_to_write)
2144                         sectors = sect_to_write;
2145                 /* Write at 'sector' for 'sectors'*/
2146
2147                 wbio = bio_alloc_mddev(GFP_NOIO, vcnt, mddev);
2148                 memcpy(wbio->bi_io_vec, vec, vcnt * sizeof(struct bio_vec));
2149                 wbio->bi_sector = r1_bio->sector;
2150                 wbio->bi_rw = WRITE;
2151                 wbio->bi_vcnt = vcnt;
2152                 wbio->bi_size = r1_bio->sectors << 9;
2153                 wbio->bi_idx = idx;
2154
2155                 md_trim_bio(wbio, sector - r1_bio->sector, sectors);
2156                 wbio->bi_sector += rdev->data_offset;
2157                 wbio->bi_bdev = rdev->bdev;
2158                 if (submit_bio_wait(WRITE, wbio) == 0)
2159                         /* failure! */
2160                         ok = rdev_set_badblocks(rdev, sector,
2161                                                 sectors, 0)
2162                                 && ok;
2163
2164                 bio_put(wbio);
2165                 sect_to_write -= sectors;
2166                 sector += sectors;
2167                 sectors = block_sectors;
2168         }
2169         return ok;
2170 }
2171
2172 static void handle_sync_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2173 {
2174         int m;
2175         int s = r1_bio->sectors;
2176         for (m = 0; m < conf->raid_disks * 2 ; m++) {
2177                 struct md_rdev *rdev = conf->mirrors[m].rdev;
2178                 struct bio *bio = r1_bio->bios[m];
2179                 if (bio->bi_end_io == NULL)
2180                         continue;
2181                 if (test_bit(BIO_UPTODATE, &bio->bi_flags) &&
2182                     test_bit(R1BIO_MadeGood, &r1_bio->state)) {
2183                         rdev_clear_badblocks(rdev, r1_bio->sector, s, 0);
2184                 }
2185                 if (!test_bit(BIO_UPTODATE, &bio->bi_flags) &&
2186                     test_bit(R1BIO_WriteError, &r1_bio->state)) {
2187                         if (!rdev_set_badblocks(rdev, r1_bio->sector, s, 0))
2188                                 md_error(conf->mddev, rdev);
2189                 }
2190         }
2191         put_buf(r1_bio);
2192         md_done_sync(conf->mddev, s, 1);
2193 }
2194
2195 static void handle_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
2196 {
2197         int m;
2198         for (m = 0; m < conf->raid_disks * 2 ; m++)
2199                 if (r1_bio->bios[m] == IO_MADE_GOOD) {
2200                         struct md_rdev *rdev = conf->mirrors[m].rdev;
2201                         rdev_clear_badblocks(rdev,
2202                                              r1_bio->sector,
2203                                              r1_bio->sectors, 0);
2204                         rdev_dec_pending(rdev, conf->mddev);
2205                 } else if (r1_bio->bios[m] != NULL) {
2206                         /* This drive got a write error.  We need to
2207                          * narrow down and record precise write
2208                          * errors.
2209                          */
2210                         if (!narrow_write_error(r1_bio, m)) {
2211                                 md_error(conf->mddev,
2212                                          conf->mirrors[m].rdev);
2213                                 /* an I/O failed, we can't clear the bitmap */
2214                                 set_bit(R1BIO_Degraded, &r1_bio->state);
2215                         }
2216                         rdev_dec_pending(conf->mirrors[m].rdev,
2217                                          conf->mddev);
2218                 }
2219         if (test_bit(R1BIO_WriteError, &r1_bio->state))
2220                 close_write(r1_bio);
2221         raid_end_bio_io(r1_bio);
2222 }
2223
2224 static void handle_read_error(struct r1conf *conf, struct r1bio *r1_bio)
2225 {
2226         int disk;
2227         int max_sectors;
2228         struct mddev *mddev = conf->mddev;
2229         struct bio *bio;
2230         char b[BDEVNAME_SIZE];
2231         struct md_rdev *rdev;
2232
2233         clear_bit(R1BIO_ReadError, &r1_bio->state);
2234         /* we got a read error. Maybe the drive is bad.  Maybe just
2235          * the block and we can fix it.
2236          * We freeze all other IO, and try reading the block from
2237          * other devices.  When we find one, we re-write
2238          * and check it that fixes the read error.
2239          * This is all done synchronously while the array is
2240          * frozen
2241          */
2242         if (mddev->ro == 0) {
2243                 freeze_array(conf, 1);
2244                 fix_read_error(conf, r1_bio->read_disk,
2245                                r1_bio->sector, r1_bio->sectors);
2246                 unfreeze_array(conf);
2247         } else
2248                 md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
2249         rdev_dec_pending(conf->mirrors[r1_bio->read_disk].rdev, conf->mddev);
2250
2251         bio = r1_bio->bios[r1_bio->read_disk];
2252         bdevname(bio->bi_bdev, b);
2253 read_more:
2254         disk = read_balance(conf, r1_bio, &max_sectors);
2255         if (disk == -1) {
2256                 printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O"
2257                        " read error for block %llu\n",
2258                        mdname(mddev), b, (unsigned long long)r1_bio->sector);
2259                 raid_end_bio_io(r1_bio);
2260         } else {
2261                 const unsigned long do_sync
2262                         = r1_bio->master_bio->bi_rw & REQ_SYNC;
2263                 if (bio) {
2264                         r1_bio->bios[r1_bio->read_disk] =
2265                                 mddev->ro ? IO_BLOCKED : NULL;
2266                         bio_put(bio);
2267                 }
2268                 r1_bio->read_disk = disk;
2269                 bio = bio_clone_mddev(r1_bio->master_bio, GFP_NOIO, mddev);
2270                 md_trim_bio(bio, r1_bio->sector - bio->bi_sector, max_sectors);
2271                 r1_bio->bios[r1_bio->read_disk] = bio;
2272                 rdev = conf->mirrors[disk].rdev;
2273                 printk_ratelimited(KERN_ERR
2274                                    "md/raid1:%s: redirecting sector %llu"
2275                                    " to other mirror: %s\n",
2276                                    mdname(mddev),
2277                                    (unsigned long long)r1_bio->sector,
2278                                    bdevname(rdev->bdev, b));
2279                 bio->bi_sector = r1_bio->sector + rdev->data_offset;
2280                 bio->bi_bdev = rdev->bdev;
2281                 bio->bi_end_io = raid1_end_read_request;
2282                 bio->bi_rw = READ | do_sync;
2283                 bio->bi_private = r1_bio;
2284                 if (max_sectors < r1_bio->sectors) {
2285                         /* Drat - have to split this up more */
2286                         struct bio *mbio = r1_bio->master_bio;
2287                         int sectors_handled = (r1_bio->sector + max_sectors
2288                                                - mbio->bi_sector);
2289                         r1_bio->sectors = max_sectors;
2290                         spin_lock_irq(&conf->device_lock);
2291                         if (mbio->bi_phys_segments == 0)
2292                                 mbio->bi_phys_segments = 2;
2293                         else
2294                                 mbio->bi_phys_segments++;
2295                         spin_unlock_irq(&conf->device_lock);
2296                         generic_make_request(bio);
2297                         bio = NULL;
2298
2299                         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
2300
2301                         r1_bio->master_bio = mbio;
2302                         r1_bio->sectors = (mbio->bi_size >> 9)
2303                                           - sectors_handled;
2304                         r1_bio->state = 0;
2305                         set_bit(R1BIO_ReadError, &r1_bio->state);
2306                         r1_bio->mddev = mddev;
2307                         r1_bio->sector = mbio->bi_sector + sectors_handled;
2308
2309                         goto read_more;
2310                 } else
2311                         generic_make_request(bio);
2312         }
2313 }
2314
2315 static void raid1d(struct md_thread *thread)
2316 {
2317         struct mddev *mddev = thread->mddev;
2318         struct r1bio *r1_bio;
2319         unsigned long flags;
2320         struct r1conf *conf = mddev->private;
2321         struct list_head *head = &conf->retry_list;
2322         struct blk_plug plug;
2323
2324         md_check_recovery(mddev);
2325
2326         blk_start_plug(&plug);
2327         for (;;) {
2328
2329                 flush_pending_writes(conf);
2330
2331                 spin_lock_irqsave(&conf->device_lock, flags);
2332                 if (list_empty(head)) {
2333                         spin_unlock_irqrestore(&conf->device_lock, flags);
2334                         break;
2335                 }
2336                 r1_bio = list_entry(head->prev, struct r1bio, retry_list);
2337                 list_del(head->prev);
2338                 conf->nr_queued--;
2339                 spin_unlock_irqrestore(&conf->device_lock, flags);
2340
2341                 mddev = r1_bio->mddev;
2342                 conf = mddev->private;
2343                 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
2344                         if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2345                             test_bit(R1BIO_WriteError, &r1_bio->state))
2346                                 handle_sync_write_finished(conf, r1_bio);
2347                         else
2348                                 sync_request_write(mddev, r1_bio);
2349                 } else if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2350                            test_bit(R1BIO_WriteError, &r1_bio->state))
2351                         handle_write_finished(conf, r1_bio);
2352                 else if (test_bit(R1BIO_ReadError, &r1_bio->state))
2353                         handle_read_error(conf, r1_bio);
2354                 else
2355                         /* just a partial read to be scheduled from separate
2356                          * context
2357                          */
2358                         generic_make_request(r1_bio->bios[r1_bio->read_disk]);
2359
2360                 cond_resched();
2361                 if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
2362                         md_check_recovery(mddev);
2363         }
2364         blk_finish_plug(&plug);
2365 }
2366
2367
2368 static int init_resync(struct r1conf *conf)
2369 {
2370         int buffs;
2371
2372         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
2373         BUG_ON(conf->r1buf_pool);
2374         conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
2375                                           conf->poolinfo);
2376         if (!conf->r1buf_pool)
2377                 return -ENOMEM;
2378         conf->next_resync = 0;
2379         return 0;
2380 }
2381
2382 /*
2383  * perform a "sync" on one "block"
2384  *
2385  * We need to make sure that no normal I/O request - particularly write
2386  * requests - conflict with active sync requests.
2387  *
2388  * This is achieved by tracking pending requests and a 'barrier' concept
2389  * that can be installed to exclude normal IO requests.
2390  */
2391
2392 static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster)
2393 {
2394         struct r1conf *conf = mddev->private;
2395         struct r1bio *r1_bio;
2396         struct bio *bio;
2397         sector_t max_sector, nr_sectors;
2398         int disk = -1;
2399         int i;
2400         int wonly = -1;
2401         int write_targets = 0, read_targets = 0;
2402         sector_t sync_blocks;
2403         int still_degraded = 0;
2404         int good_sectors = RESYNC_SECTORS;
2405         int min_bad = 0; /* number of sectors that are bad in all devices */
2406
2407         if (!conf->r1buf_pool)
2408                 if (init_resync(conf))
2409                         return 0;
2410
2411         max_sector = mddev->dev_sectors;
2412         if (sector_nr >= max_sector) {
2413                 /* If we aborted, we need to abort the
2414                  * sync on the 'current' bitmap chunk (there will
2415                  * only be one in raid1 resync.
2416                  * We can find the current addess in mddev->curr_resync
2417                  */
2418                 if (mddev->curr_resync < max_sector) /* aborted */
2419                         bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
2420                                                 &sync_blocks, 1);
2421                 else /* completed sync */
2422                         conf->fullsync = 0;
2423
2424                 bitmap_close_sync(mddev->bitmap);
2425                 close_sync(conf);
2426                 return 0;
2427         }
2428
2429         if (mddev->bitmap == NULL &&
2430             mddev->recovery_cp == MaxSector &&
2431             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
2432             conf->fullsync == 0) {
2433                 *skipped = 1;
2434                 return max_sector - sector_nr;
2435         }
2436         /* before building a request, check if we can skip these blocks..
2437          * This call the bitmap_start_sync doesn't actually record anything
2438          */
2439         if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
2440             !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2441                 /* We can skip this block, and probably several more */
2442                 *skipped = 1;
2443                 return sync_blocks;
2444         }
2445         /*
2446          * If there is non-resync activity waiting for a turn,
2447          * and resync is going fast enough,
2448          * then let it though before starting on this new sync request.
2449          */
2450         if (!go_faster && conf->nr_waiting)
2451                 msleep_interruptible(1000);
2452
2453         bitmap_cond_end_sync(mddev->bitmap, sector_nr);
2454         r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
2455         raise_barrier(conf);
2456
2457         conf->next_resync = sector_nr;
2458
2459         rcu_read_lock();
2460         /*
2461          * If we get a correctably read error during resync or recovery,
2462          * we might want to read from a different device.  So we
2463          * flag all drives that could conceivably be read from for READ,
2464          * and any others (which will be non-In_sync devices) for WRITE.
2465          * If a read fails, we try reading from something else for which READ
2466          * is OK.
2467          */
2468
2469         r1_bio->mddev = mddev;
2470         r1_bio->sector = sector_nr;
2471         r1_bio->state = 0;
2472         set_bit(R1BIO_IsSync, &r1_bio->state);
2473
2474         for (i = 0; i < conf->raid_disks * 2; i++) {
2475                 struct md_rdev *rdev;
2476                 bio = r1_bio->bios[i];
2477
2478                 /* take from bio_init */
2479                 bio->bi_next = NULL;
2480                 bio->bi_flags &= ~(BIO_POOL_MASK-1);
2481                 bio->bi_flags |= 1 << BIO_UPTODATE;
2482                 bio->bi_rw = READ;
2483                 bio->bi_vcnt = 0;
2484                 bio->bi_idx = 0;
2485                 bio->bi_phys_segments = 0;
2486                 bio->bi_size = 0;
2487                 bio->bi_end_io = NULL;
2488                 bio->bi_private = NULL;
2489
2490                 rdev = rcu_dereference(conf->mirrors[i].rdev);
2491                 if (rdev == NULL ||
2492                     test_bit(Faulty, &rdev->flags)) {
2493                         if (i < conf->raid_disks)
2494                                 still_degraded = 1;
2495                 } else if (!test_bit(In_sync, &rdev->flags)) {
2496                         bio->bi_rw = WRITE;
2497                         bio->bi_end_io = end_sync_write;
2498                         write_targets ++;
2499                 } else {
2500                         /* may need to read from here */
2501                         sector_t first_bad = MaxSector;
2502                         int bad_sectors;
2503
2504                         if (is_badblock(rdev, sector_nr, good_sectors,
2505                                         &first_bad, &bad_sectors)) {
2506                                 if (first_bad > sector_nr)
2507                                         good_sectors = first_bad - sector_nr;
2508                                 else {
2509                                         bad_sectors -= (sector_nr - first_bad);
2510                                         if (min_bad == 0 ||
2511                                             min_bad > bad_sectors)
2512                                                 min_bad = bad_sectors;
2513                                 }
2514                         }
2515                         if (sector_nr < first_bad) {
2516                                 if (test_bit(WriteMostly, &rdev->flags)) {
2517                                         if (wonly < 0)
2518                                                 wonly = i;
2519                                 } else {
2520                                         if (disk < 0)
2521                                                 disk = i;
2522                                 }
2523                                 bio->bi_rw = READ;
2524                                 bio->bi_end_io = end_sync_read;
2525                                 read_targets++;
2526                         } else if (!test_bit(WriteErrorSeen, &rdev->flags) &&
2527                                 test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
2528                                 !test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) {
2529                                 /*
2530                                  * The device is suitable for reading (InSync),
2531                                  * but has bad block(s) here. Let's try to correct them,
2532                                  * if we are doing resync or repair. Otherwise, leave
2533                                  * this device alone for this sync request.
2534                                  */
2535                                 bio->bi_rw = WRITE;
2536                                 bio->bi_end_io = end_sync_write;
2537                                 write_targets++;
2538                         }
2539                 }
2540                 if (bio->bi_end_io) {
2541                         atomic_inc(&rdev->nr_pending);
2542                         bio->bi_sector = sector_nr + rdev->data_offset;
2543                         bio->bi_bdev = rdev->bdev;
2544                         bio->bi_private = r1_bio;
2545                 }
2546         }
2547         rcu_read_unlock();
2548         if (disk < 0)
2549                 disk = wonly;
2550         r1_bio->read_disk = disk;
2551
2552         if (read_targets == 0 && min_bad > 0) {
2553                 /* These sectors are bad on all InSync devices, so we
2554                  * need to mark them bad on all write targets
2555                  */
2556                 int ok = 1;
2557                 for (i = 0 ; i < conf->raid_disks * 2 ; i++)
2558                         if (r1_bio->bios[i]->bi_end_io == end_sync_write) {
2559                                 struct md_rdev *rdev = conf->mirrors[i].rdev;
2560                                 ok = rdev_set_badblocks(rdev, sector_nr,
2561                                                         min_bad, 0
2562                                         ) && ok;
2563                         }
2564                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
2565                 *skipped = 1;
2566                 put_buf(r1_bio);
2567
2568                 if (!ok) {
2569                         /* Cannot record the badblocks, so need to
2570                          * abort the resync.
2571                          * If there are multiple read targets, could just
2572                          * fail the really bad ones ???
2573                          */
2574                         conf->recovery_disabled = mddev->recovery_disabled;
2575                         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2576                         return 0;
2577                 } else
2578                         return min_bad;
2579
2580         }
2581         if (min_bad > 0 && min_bad < good_sectors) {
2582                 /* only resync enough to reach the next bad->good
2583                  * transition */
2584                 good_sectors = min_bad;
2585         }
2586
2587         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
2588                 /* extra read targets are also write targets */
2589                 write_targets += read_targets-1;
2590
2591         if (write_targets == 0 || read_targets == 0) {
2592                 /* There is nowhere to write, so all non-sync
2593                  * drives must be failed - so we are finished
2594                  */
2595                 sector_t rv;
2596                 if (min_bad > 0)
2597                         max_sector = sector_nr + min_bad;
2598                 rv = max_sector - sector_nr;
2599                 *skipped = 1;
2600                 put_buf(r1_bio);
2601                 return rv;
2602         }
2603
2604         if (max_sector > mddev->resync_max)
2605                 max_sector = mddev->resync_max; /* Don't do IO beyond here */
2606         if (max_sector > sector_nr + good_sectors)
2607                 max_sector = sector_nr + good_sectors;
2608         nr_sectors = 0;
2609         sync_blocks = 0;
2610         do {
2611                 struct page *page;
2612                 int len = PAGE_SIZE;
2613                 if (sector_nr + (len>>9) > max_sector)
2614                         len = (max_sector - sector_nr) << 9;
2615                 if (len == 0)
2616                         break;
2617                 if (sync_blocks == 0) {
2618                         if (!bitmap_start_sync(mddev->bitmap, sector_nr,
2619                                                &sync_blocks, still_degraded) &&
2620                             !conf->fullsync &&
2621                             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2622                                 break;
2623                         BUG_ON(sync_blocks < (PAGE_SIZE>>9));
2624                         if ((len >> 9) > sync_blocks)
2625                                 len = sync_blocks<<9;
2626                 }
2627
2628                 for (i = 0 ; i < conf->raid_disks * 2; i++) {
2629                         bio = r1_bio->bios[i];
2630                         if (bio->bi_end_io) {
2631                                 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
2632                                 if (bio_add_page(bio, page, len, 0) == 0) {
2633                                         /* stop here */
2634                                         bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
2635                                         while (i > 0) {
2636                                                 i--;
2637                                                 bio = r1_bio->bios[i];
2638                                                 if (bio->bi_end_io==NULL)
2639                                                         continue;
2640                                                 /* remove last page from this bio */
2641                                                 bio->bi_vcnt--;
2642                                                 bio->bi_size -= len;
2643                                                 bio->bi_flags &= ~(1<< BIO_SEG_VALID);
2644                                         }
2645                                         goto bio_full;
2646                                 }
2647                         }
2648                 }
2649                 nr_sectors += len>>9;
2650                 sector_nr += len>>9;
2651                 sync_blocks -= (len>>9);
2652         } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
2653  bio_full:
2654         r1_bio->sectors = nr_sectors;
2655
2656         /* For a user-requested sync, we read all readable devices and do a
2657          * compare
2658          */
2659         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2660                 atomic_set(&r1_bio->remaining, read_targets);
2661                 for (i = 0; i < conf->raid_disks * 2 && read_targets; i++) {
2662                         bio = r1_bio->bios[i];
2663                         if (bio->bi_end_io == end_sync_read) {
2664                                 read_targets--;
2665                                 md_sync_acct(bio->bi_bdev, nr_sectors);
2666                                 generic_make_request(bio);
2667                         }
2668                 }
2669         } else {
2670                 atomic_set(&r1_bio->remaining, 1);
2671                 bio = r1_bio->bios[r1_bio->read_disk];
2672                 md_sync_acct(bio->bi_bdev, nr_sectors);
2673                 generic_make_request(bio);
2674
2675         }
2676         return nr_sectors;
2677 }
2678
2679 static sector_t raid1_size(struct mddev *mddev, sector_t sectors, int raid_disks)
2680 {
2681         if (sectors)
2682                 return sectors;
2683
2684         return mddev->dev_sectors;
2685 }
2686
2687 static struct r1conf *setup_conf(struct mddev *mddev)
2688 {
2689         struct r1conf *conf;
2690         int i;
2691         struct raid1_info *disk;
2692         struct md_rdev *rdev;
2693         int err = -ENOMEM;
2694
2695         conf = kzalloc(sizeof(struct r1conf), GFP_KERNEL);
2696         if (!conf)
2697                 goto abort;
2698
2699         conf->mirrors = kzalloc(sizeof(struct raid1_info)
2700                                 * mddev->raid_disks * 2,
2701                                  GFP_KERNEL);
2702         if (!conf->mirrors)
2703                 goto abort;
2704
2705         conf->tmppage = alloc_page(GFP_KERNEL);
2706         if (!conf->tmppage)
2707                 goto abort;
2708
2709         conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
2710         if (!conf->poolinfo)
2711                 goto abort;
2712         conf->poolinfo->raid_disks = mddev->raid_disks * 2;
2713         conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2714                                           r1bio_pool_free,
2715                                           conf->poolinfo);
2716         if (!conf->r1bio_pool)
2717                 goto abort;
2718
2719         conf->poolinfo->mddev = mddev;
2720
2721         err = -EINVAL;
2722         spin_lock_init(&conf->device_lock);
2723         rdev_for_each(rdev, mddev) {
2724                 struct request_queue *q;
2725                 int disk_idx = rdev->raid_disk;
2726                 if (disk_idx >= mddev->raid_disks
2727                     || disk_idx < 0)
2728                         continue;
2729                 if (test_bit(Replacement, &rdev->flags))
2730                         disk = conf->mirrors + mddev->raid_disks + disk_idx;
2731                 else
2732                         disk = conf->mirrors + disk_idx;
2733
2734                 if (disk->rdev)
2735                         goto abort;
2736                 disk->rdev = rdev;
2737                 q = bdev_get_queue(rdev->bdev);
2738                 if (q->merge_bvec_fn)
2739                         mddev->merge_check_needed = 1;
2740
2741                 disk->head_position = 0;
2742                 disk->seq_start = MaxSector;
2743         }
2744         conf->raid_disks = mddev->raid_disks;
2745         conf->mddev = mddev;
2746         INIT_LIST_HEAD(&conf->retry_list);
2747
2748         spin_lock_init(&conf->resync_lock);
2749         init_waitqueue_head(&conf->wait_barrier);
2750
2751         bio_list_init(&conf->pending_bio_list);
2752         conf->pending_count = 0;
2753         conf->recovery_disabled = mddev->recovery_disabled - 1;
2754
2755         err = -EIO;
2756         for (i = 0; i < conf->raid_disks * 2; i++) {
2757
2758                 disk = conf->mirrors + i;
2759
2760                 if (i < conf->raid_disks &&
2761                     disk[conf->raid_disks].rdev) {
2762                         /* This slot has a replacement. */
2763                         if (!disk->rdev) {
2764                                 /* No original, just make the replacement
2765                                  * a recovering spare
2766                                  */
2767                                 disk->rdev =
2768                                         disk[conf->raid_disks].rdev;
2769                                 disk[conf->raid_disks].rdev = NULL;
2770                         } else if (!test_bit(In_sync, &disk->rdev->flags))
2771                                 /* Original is not in_sync - bad */
2772                                 goto abort;
2773                 }
2774
2775                 if (!disk->rdev ||
2776                     !test_bit(In_sync, &disk->rdev->flags)) {
2777                         disk->head_position = 0;
2778                         if (disk->rdev &&
2779                             (disk->rdev->saved_raid_disk < 0))
2780                                 conf->fullsync = 1;
2781                 }
2782         }
2783
2784         err = -ENOMEM;
2785         conf->thread = md_register_thread(raid1d, mddev, "raid1");
2786         if (!conf->thread) {
2787                 printk(KERN_ERR
2788                        "md/raid1:%s: couldn't allocate thread\n",
2789                        mdname(mddev));
2790                 goto abort;
2791         }
2792
2793         return conf;
2794
2795  abort:
2796         if (conf) {
2797                 if (conf->r1bio_pool)
2798                         mempool_destroy(conf->r1bio_pool);
2799                 kfree(conf->mirrors);
2800                 safe_put_page(conf->tmppage);
2801                 kfree(conf->poolinfo);
2802                 kfree(conf);
2803         }
2804         return ERR_PTR(err);
2805 }
2806
2807 static int stop(struct mddev *mddev);
2808 static int run(struct mddev *mddev)
2809 {
2810         struct r1conf *conf;
2811         int i;
2812         struct md_rdev *rdev;
2813         int ret;
2814         bool discard_supported = false;
2815
2816         if (mddev->level != 1) {
2817                 printk(KERN_ERR "md/raid1:%s: raid level not set to mirroring (%d)\n",
2818                        mdname(mddev), mddev->level);
2819                 return -EIO;
2820         }
2821         if (mddev->reshape_position != MaxSector) {
2822                 printk(KERN_ERR "md/raid1:%s: reshape_position set but not supported\n",
2823                        mdname(mddev));
2824                 return -EIO;
2825         }
2826         /*
2827          * copy the already verified devices into our private RAID1
2828          * bookkeeping area. [whatever we allocate in run(),
2829          * should be freed in stop()]
2830          */
2831         if (mddev->private == NULL)
2832                 conf = setup_conf(mddev);
2833         else
2834                 conf = mddev->private;
2835
2836         if (IS_ERR(conf))
2837                 return PTR_ERR(conf);
2838
2839         if (mddev->queue)
2840                 blk_queue_max_write_same_sectors(mddev->queue, 0);
2841
2842         rdev_for_each(rdev, mddev) {
2843                 if (!mddev->gendisk)
2844                         continue;
2845                 disk_stack_limits(mddev->gendisk, rdev->bdev,
2846                                   rdev->data_offset << 9);
2847                 if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
2848                         discard_supported = true;
2849         }
2850
2851         mddev->degraded = 0;
2852         for (i=0; i < conf->raid_disks; i++)
2853                 if (conf->mirrors[i].rdev == NULL ||
2854                     !test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
2855                     test_bit(Faulty, &conf->mirrors[i].rdev->flags))
2856                         mddev->degraded++;
2857
2858         if (conf->raid_disks - mddev->degraded == 1)
2859                 mddev->recovery_cp = MaxSector;
2860
2861         if (mddev->recovery_cp != MaxSector)
2862                 printk(KERN_NOTICE "md/raid1:%s: not clean"
2863                        " -- starting background reconstruction\n",
2864                        mdname(mddev));
2865         printk(KERN_INFO
2866                 "md/raid1:%s: active with %d out of %d mirrors\n",
2867                 mdname(mddev), mddev->raid_disks - mddev->degraded,
2868                 mddev->raid_disks);
2869
2870         /*
2871          * Ok, everything is just fine now
2872          */
2873         mddev->thread = conf->thread;
2874         conf->thread = NULL;
2875         mddev->private = conf;
2876
2877         md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
2878
2879         if (mddev->queue) {
2880                 mddev->queue->backing_dev_info.congested_fn = raid1_congested;
2881                 mddev->queue->backing_dev_info.congested_data = mddev;
2882                 blk_queue_merge_bvec(mddev->queue, raid1_mergeable_bvec);
2883
2884                 if (discard_supported)
2885                         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
2886                                                 mddev->queue);
2887                 else
2888                         queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
2889                                                   mddev->queue);
2890         }
2891
2892         ret =  md_integrity_register(mddev);
2893         if (ret)
2894                 stop(mddev);
2895         return ret;
2896 }
2897
2898 static int stop(struct mddev *mddev)
2899 {
2900         struct r1conf *conf = mddev->private;
2901         struct bitmap *bitmap = mddev->bitmap;
2902
2903         /* wait for behind writes to complete */
2904         if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
2905                 printk(KERN_INFO "md/raid1:%s: behind writes in progress - waiting to stop.\n",
2906                        mdname(mddev));
2907                 /* need to kick something here to make sure I/O goes? */
2908                 wait_event(bitmap->behind_wait,
2909                            atomic_read(&bitmap->behind_writes) == 0);
2910         }
2911
2912         raise_barrier(conf);
2913         lower_barrier(conf);
2914
2915         md_unregister_thread(&mddev->thread);
2916         if (conf->r1bio_pool)
2917                 mempool_destroy(conf->r1bio_pool);
2918         kfree(conf->mirrors);
2919         safe_put_page(conf->tmppage);
2920         kfree(conf->poolinfo);
2921         kfree(conf);
2922         mddev->private = NULL;
2923         return 0;
2924 }
2925
2926 static int raid1_resize(struct mddev *mddev, sector_t sectors)
2927 {
2928         /* no resync is happening, and there is enough space
2929          * on all devices, so we can resize.
2930          * We need to make sure resync covers any new space.
2931          * If the array is shrinking we should possibly wait until
2932          * any io in the removed space completes, but it hardly seems
2933          * worth it.
2934          */
2935         sector_t newsize = raid1_size(mddev, sectors, 0);
2936         if (mddev->external_size &&
2937             mddev->array_sectors > newsize)
2938                 return -EINVAL;
2939         if (mddev->bitmap) {
2940                 int ret = bitmap_resize(mddev->bitmap, newsize, 0, 0);
2941                 if (ret)
2942                         return ret;
2943         }
2944         md_set_array_sectors(mddev, newsize);
2945         set_capacity(mddev->gendisk, mddev->array_sectors);
2946         revalidate_disk(mddev->gendisk);
2947         if (sectors > mddev->dev_sectors &&
2948             mddev->recovery_cp > mddev->dev_sectors) {
2949                 mddev->recovery_cp = mddev->dev_sectors;
2950                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2951         }
2952         mddev->dev_sectors = sectors;
2953         mddev->resync_max_sectors = sectors;
2954         return 0;
2955 }
2956
2957 static int raid1_reshape(struct mddev *mddev)
2958 {
2959         /* We need to:
2960          * 1/ resize the r1bio_pool
2961          * 2/ resize conf->mirrors
2962          *
2963          * We allocate a new r1bio_pool if we can.
2964          * Then raise a device barrier and wait until all IO stops.
2965          * Then resize conf->mirrors and swap in the new r1bio pool.
2966          *
2967          * At the same time, we "pack" the devices so that all the missing
2968          * devices have the higher raid_disk numbers.
2969          */
2970         mempool_t *newpool, *oldpool;
2971         struct pool_info *newpoolinfo;
2972         struct raid1_info *newmirrors;
2973         struct r1conf *conf = mddev->private;
2974         int cnt, raid_disks;
2975         unsigned long flags;
2976         int d, d2, err;
2977
2978         /* Cannot change chunk_size, layout, or level */
2979         if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
2980             mddev->layout != mddev->new_layout ||
2981             mddev->level != mddev->new_level) {
2982                 mddev->new_chunk_sectors = mddev->chunk_sectors;
2983                 mddev->new_layout = mddev->layout;
2984                 mddev->new_level = mddev->level;
2985                 return -EINVAL;
2986         }
2987
2988         err = md_allow_write(mddev);
2989         if (err)
2990                 return err;
2991
2992         raid_disks = mddev->raid_disks + mddev->delta_disks;
2993
2994         if (raid_disks < conf->raid_disks) {
2995                 cnt=0;
2996                 for (d= 0; d < conf->raid_disks; d++)
2997                         if (conf->mirrors[d].rdev)
2998                                 cnt++;
2999                 if (cnt > raid_disks)
3000                         return -EBUSY;
3001         }
3002
3003         newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
3004         if (!newpoolinfo)
3005                 return -ENOMEM;
3006         newpoolinfo->mddev = mddev;
3007         newpoolinfo->raid_disks = raid_disks * 2;
3008
3009         newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
3010                                  r1bio_pool_free, newpoolinfo);
3011         if (!newpool) {
3012                 kfree(newpoolinfo);
3013                 return -ENOMEM;
3014         }
3015         newmirrors = kzalloc(sizeof(struct raid1_info) * raid_disks * 2,
3016                              GFP_KERNEL);
3017         if (!newmirrors) {
3018                 kfree(newpoolinfo);
3019                 mempool_destroy(newpool);
3020                 return -ENOMEM;
3021         }
3022
3023         freeze_array(conf, 0);
3024
3025         /* ok, everything is stopped */
3026         oldpool = conf->r1bio_pool;
3027         conf->r1bio_pool = newpool;
3028
3029         for (d = d2 = 0; d < conf->raid_disks; d++) {
3030                 struct md_rdev *rdev = conf->mirrors[d].rdev;
3031                 if (rdev && rdev->raid_disk != d2) {
3032                         sysfs_unlink_rdev(mddev, rdev);
3033                         rdev->raid_disk = d2;
3034                         sysfs_unlink_rdev(mddev, rdev);
3035                         if (sysfs_link_rdev(mddev, rdev))
3036                                 printk(KERN_WARNING
3037                                        "md/raid1:%s: cannot register rd%d\n",
3038                                        mdname(mddev), rdev->raid_disk);
3039                 }
3040                 if (rdev)
3041                         newmirrors[d2++].rdev = rdev;
3042         }
3043         kfree(conf->mirrors);
3044         conf->mirrors = newmirrors;
3045         kfree(conf->poolinfo);
3046         conf->poolinfo = newpoolinfo;
3047
3048         spin_lock_irqsave(&conf->device_lock, flags);
3049         mddev->degraded += (raid_disks - conf->raid_disks);
3050         spin_unlock_irqrestore(&conf->device_lock, flags);
3051         conf->raid_disks = mddev->raid_disks = raid_disks;
3052         mddev->delta_disks = 0;
3053
3054         unfreeze_array(conf);
3055
3056         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3057         md_wakeup_thread(mddev->thread);
3058
3059         mempool_destroy(oldpool);
3060         return 0;
3061 }
3062
3063 static void raid1_quiesce(struct mddev *mddev, int state)
3064 {
3065         struct r1conf *conf = mddev->private;
3066
3067         switch(state) {
3068         case 2: /* wake for suspend */
3069                 wake_up(&conf->wait_barrier);
3070                 break;
3071         case 1:
3072                 raise_barrier(conf);
3073                 break;
3074         case 0:
3075                 lower_barrier(conf);
3076                 break;
3077         }
3078 }
3079
3080 static void *raid1_takeover(struct mddev *mddev)
3081 {
3082         /* raid1 can take over:
3083          *  raid5 with 2 devices, any layout or chunk size
3084          */
3085         if (mddev->level == 5 && mddev->raid_disks == 2) {
3086                 struct r1conf *conf;
3087                 mddev->new_level = 1;
3088                 mddev->new_layout = 0;
3089                 mddev->new_chunk_sectors = 0;
3090                 conf = setup_conf(mddev);
3091                 if (!IS_ERR(conf))
3092                         conf->barrier = 1;
3093                 return conf;
3094         }
3095         return ERR_PTR(-EINVAL);
3096 }
3097
3098 static struct md_personality raid1_personality =
3099 {
3100         .name           = "raid1",
3101         .level          = 1,
3102         .owner          = THIS_MODULE,
3103         .make_request   = make_request,
3104         .run            = run,
3105         .stop           = stop,
3106         .status         = status,
3107         .error_handler  = error,
3108         .hot_add_disk   = raid1_add_disk,
3109         .hot_remove_disk= raid1_remove_disk,
3110         .spare_active   = raid1_spare_active,
3111         .sync_request   = sync_request,
3112         .resize         = raid1_resize,
3113         .size           = raid1_size,
3114         .check_reshape  = raid1_reshape,
3115         .quiesce        = raid1_quiesce,
3116         .takeover       = raid1_takeover,
3117 };
3118
3119 static int __init raid_init(void)
3120 {
3121         return register_md_personality(&raid1_personality);
3122 }
3123
3124 static void raid_exit(void)
3125 {
3126         unregister_md_personality(&raid1_personality);
3127 }
3128
3129 module_init(raid_init);
3130 module_exit(raid_exit);
3131 MODULE_LICENSE("GPL");
3132 MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
3133 MODULE_ALIAS("md-personality-3"); /* RAID1 */
3134 MODULE_ALIAS("md-raid1");
3135 MODULE_ALIAS("md-level-1");
3136
3137 module_param(max_queued_requests, int, S_IRUGO|S_IWUSR);