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/seq_file.h>
  38 #include <linux/ratelimit.h>
  39 #include "md.h"
  40 #include "raid1.h"
  41 #include "bitmap.h"
  42
  43 #define DEBUG 0
  44 #define PRINTK(x...) do { if (DEBUG) printk(x); } while (0)
  45
  46 /*
  47  * Number of guaranteed r1bios in case of extreme VM load:
  48  */
  49 #define NR_RAID1_BIOS 256
  50
  51
  52 static void allow_barrier(conf_t *conf);
  53 static void lower_barrier(conf_t *conf);
  54
  55 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
  56 {
  57         struct pool_info *pi = data;
  58         int size = offsetof(r1bio_t, bios[pi->raid_disks]);
  59
  60         /* allocate a r1bio with room for raid_disks entries in the bios array */
  61         return kzalloc(size, gfp_flags);
  62 }
  63
  64 static void r1bio_pool_free(void *r1_bio, void *data)
  65 {
  66         kfree(r1_bio);
  67 }
  68
  69 #define RESYNC_BLOCK_SIZE (64*1024)
  70 //#define RESYNC_BLOCK_SIZE PAGE_SIZE
  71 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
  72 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
  73 #define RESYNC_WINDOW (2048*1024)
  74
  75 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
  76 {
  77         struct pool_info *pi = data;
  78         struct page *page;
  79         r1bio_t *r1_bio;
  80         struct bio *bio;
  81         int i, j;
  82
  83         r1_bio = r1bio_pool_alloc(gfp_flags, pi);
  84         if (!r1_bio)
  85                 return NULL;
  86
  87         /*
  88          * Allocate bios : 1 for reading, n-1 for writing
  89          */
  90         for (j = pi->raid_disks ; j-- ; ) {
  91                 bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
  92                 if (!bio)
  93                         goto out_free_bio;
  94                 r1_bio->bios[j] = bio;
  95         }
  96         /*
  97          * Allocate RESYNC_PAGES data pages and attach them to
  98          * the first bio.
  99          * If this is a user-requested check/repair, allocate
 100          * RESYNC_PAGES for each bio.
 101          */
 102         if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
 103                 j = pi->raid_disks;
 104         else
 105                 j = 1;
 106         while(j--) {
 107                 bio = r1_bio->bios[j];
 108                 for (i = 0; i < RESYNC_PAGES; i++) {
 109                         page = alloc_page(gfp_flags);
 110                         if (unlikely(!page))
 111                                 goto out_free_pages;
 112
 113                         bio->bi_io_vec[i].bv_page = page;
 114                         bio->bi_vcnt = i+1;
 115                 }
 116         }
 117         /* If not user-requests, copy the page pointers to all bios */
 118         if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
 119                 for (i=0; i<RESYNC_PAGES ; i++)
 120                         for (j=1; j<pi->raid_disks; j++)
 121                                 r1_bio->bios[j]->bi_io_vec[i].bv_page =
 122                                         r1_bio->bios[0]->bi_io_vec[i].bv_page;
 123         }
 124
 125         r1_bio->master_bio = NULL;
 126
 127         return r1_bio;
 128
 129 out_free_pages:
 130         for (j=0 ; j < pi->raid_disks; j++)
 131                 for (i=0; i < r1_bio->bios[j]->bi_vcnt ; i++)
 132                         put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
 133         j = -1;
 134 out_free_bio:
 135         while ( ++j < pi->raid_disks )
 136                 bio_put(r1_bio->bios[j]);
 137         r1bio_pool_free(r1_bio, data);
 138         return NULL;
 139 }
 140
 141 static void r1buf_pool_free(void *__r1_bio, void *data)
 142 {
 143         struct pool_info *pi = data;
 144         int i,j;
 145         r1bio_t *r1bio = __r1_bio;
 146
 147         for (i = 0; i < RESYNC_PAGES; i++)
 148                 for (j = pi->raid_disks; j-- ;) {
 149                         if (j == 0 ||
 150                             r1bio->bios[j]->bi_io_vec[i].bv_page !=
 151                             r1bio->bios[0]->bi_io_vec[i].bv_page)
 152                                 safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page);
 153                 }
 154         for (i=0 ; i < pi->raid_disks; i++)
 155                 bio_put(r1bio->bios[i]);
 156
 157         r1bio_pool_free(r1bio, data);
 158 }
 159
 160 static void put_all_bios(conf_t *conf, r1bio_t *r1_bio)
 161 {
 162         int i;
 163
 164         for (i = 0; i < conf->raid_disks; i++) {
 165                 struct bio **bio = r1_bio->bios + i;
 166                 if (!BIO_SPECIAL(*bio))
 167                         bio_put(*bio);
 168                 *bio = NULL;
 169         }
 170 }
 171
 172 static void free_r1bio(r1bio_t *r1_bio)
 173 {
 174         conf_t *conf = r1_bio->mddev->private;
 175
 176         put_all_bios(conf, r1_bio);
 177         mempool_free(r1_bio, conf->r1bio_pool);
 178 }
 179
 180 static void put_buf(r1bio_t *r1_bio)
 181 {
 182         conf_t *conf = r1_bio->mddev->private;
 183         int i;
 184
 185         for (i=0; i<conf->raid_disks; i++) {
 186                 struct bio *bio = r1_bio->bios[i];
 187                 if (bio->bi_end_io)
 188                         rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
 189         }
 190
 191         mempool_free(r1_bio, conf->r1buf_pool);
 192
 193         lower_barrier(conf);
 194 }
 195
 196 static void reschedule_retry(r1bio_t *r1_bio)
 197 {
 198         unsigned long flags;
 199         mddev_t *mddev = r1_bio->mddev;
 200         conf_t *conf = mddev->private;
 201
 202         spin_lock_irqsave(&conf->device_lock, flags);
 203         list_add(&r1_bio->retry_list, &conf->retry_list);
 204         conf->nr_queued ++;
 205         spin_unlock_irqrestore(&conf->device_lock, flags);
 206
 207         wake_up(&conf->wait_barrier);
 208         md_wakeup_thread(mddev->thread);
 209 }
 210
 211 /*
 212  * raid_end_bio_io() is called when we have finished servicing a mirrored
 213  * operation and are ready to return a success/failure code to the buffer
 214  * cache layer.
 215  */
 216 static void call_bio_endio(r1bio_t *r1_bio)
 217 {
 218         struct bio *bio = r1_bio->master_bio;
 219         int done;
 220         conf_t *conf = r1_bio->mddev->private;
 221
 222         if (bio->bi_phys_segments) {
 223                 unsigned long flags;
 224                 spin_lock_irqsave(&conf->device_lock, flags);
 225                 bio->bi_phys_segments--;
 226                 done = (bio->bi_phys_segments == 0);
 227                 spin_unlock_irqrestore(&conf->device_lock, flags);
 228         } else
 229                 done = 1;
 230
 231         if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
 232                 clear_bit(BIO_UPTODATE, &bio->bi_flags);
 233         if (done) {
 234                 bio_endio(bio, 0);
 235                 /*
 236                  * Wake up any possible resync thread that waits for the device
 237                  * to go idle.
 238                  */
 239                 allow_barrier(conf);
 240         }
 241 }
 242
 243 static void raid_end_bio_io(r1bio_t *r1_bio)
 244 {
 245         struct bio *bio = r1_bio->master_bio;
 246
 247         /* if nobody has done the final endio yet, do it now */
 248         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 249                 PRINTK(KERN_DEBUG "raid1: sync end %s on sectors %llu-%llu\n",
 250                         (bio_data_dir(bio) == WRITE) ? "write" : "read",
 251                         (unsigned long long) bio->bi_sector,
 252                         (unsigned long long) bio->bi_sector +
 253                                 (bio->bi_size >> 9) - 1);
 254
 255                 call_bio_endio(r1_bio);
 256         }
 257         free_r1bio(r1_bio);
 258 }
 259
 260 /*
 261  * Update disk head position estimator based on IRQ completion info.
 262  */
 263 static inline void update_head_pos(int disk, r1bio_t *r1_bio)
 264 {
 265         conf_t *conf = r1_bio->mddev->private;
 266
 267         conf->mirrors[disk].head_position =
 268                 r1_bio->sector + (r1_bio->sectors);
 269 }
 270
 271 static void raid1_end_read_request(struct bio *bio, int error)
 272 {
 273         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 274         r1bio_t *r1_bio = bio->bi_private;
 275         int mirror;
 276         conf_t *conf = r1_bio->mddev->private;
 277
 278         mirror = r1_bio->read_disk;
 279         /*
 280          * this branch is our 'one mirror IO has finished' event handler:
 281          */
 282         update_head_pos(mirror, r1_bio);
 283
 284         if (uptodate)
 285                 set_bit(R1BIO_Uptodate, &r1_bio->state);
 286         else {
 287                 /* If all other devices have failed, we want to return
 288                  * the error upwards rather than fail the last device.
 289                  * Here we redefine "uptodate" to mean "Don't want to retry"
 290                  */
 291                 unsigned long flags;
 292                 spin_lock_irqsave(&conf->device_lock, flags);
 293                 if (r1_bio->mddev->degraded == conf->raid_disks ||
 294                     (r1_bio->mddev->degraded == conf->raid_disks-1 &&
 295                      !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags)))
 296                         uptodate = 1;
 297                 spin_unlock_irqrestore(&conf->device_lock, flags);
 298         }
 299
 300         if (uptodate)
 301                 raid_end_bio_io(r1_bio);
 302         else {
 303                 /*
 304                  * oops, read error:
 305                  */
 306                 char b[BDEVNAME_SIZE];
 307                 printk_ratelimited(
 308                         KERN_ERR "md/raid1:%s: %s: "
 309                         "rescheduling sector %llu\n",
 310                         mdname(conf->mddev),
 311                         bdevname(conf->mirrors[mirror].rdev->bdev,
 312                                  b),
 313                         (unsigned long long)r1_bio->sector);
 314                 set_bit(R1BIO_ReadError, &r1_bio->state);
 315                 reschedule_retry(r1_bio);
 316         }
 317
 318         rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
 319 }
 320
 321 static void close_write(r1bio_t *r1_bio)
 322 {
 323         /* it really is the end of this request */
 324         if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
 325                 /* free extra copy of the data pages */
 326                 int i = r1_bio->behind_page_count;
 327                 while (i--)
 328                         safe_put_page(r1_bio->behind_bvecs[i].bv_page);
 329                 kfree(r1_bio->behind_bvecs);
 330                 r1_bio->behind_bvecs = NULL;
 331         }
 332         /* clear the bitmap if all writes complete successfully */
 333         bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
 334                         r1_bio->sectors,
 335                         !test_bit(R1BIO_Degraded, &r1_bio->state),
 336                         test_bit(R1BIO_BehindIO, &r1_bio->state));
 337         md_write_end(r1_bio->mddev);
 338 }
 339
 340 static void r1_bio_write_done(r1bio_t *r1_bio)
 341 {
 342         if (!atomic_dec_and_test(&r1_bio->remaining))
 343                 return;
 344
 345         if (test_bit(R1BIO_WriteError, &r1_bio->state))
 346                 reschedule_retry(r1_bio);
 347         else {
 348                 close_write(r1_bio);
 349                 if (test_bit(R1BIO_MadeGood, &r1_bio->state))
 350                         reschedule_retry(r1_bio);
 351                 else
 352                         raid_end_bio_io(r1_bio);
 353         }
 354 }
 355
 356 static void raid1_end_write_request(struct bio *bio, int error)
 357 {
 358         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 359         r1bio_t *r1_bio = bio->bi_private;
 360         int mirror, behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
 361         conf_t *conf = r1_bio->mddev->private;
 362         struct bio *to_put = NULL;
 363
 364
 365         for (mirror = 0; mirror < conf->raid_disks; mirror++)
 366                 if (r1_bio->bios[mirror] == bio)
 367                         break;
 368
 369         /*
 370          * 'one mirror IO has finished' event handler:
 371          */
 372         if (!uptodate) {
 373                 set_bit(WriteErrorSeen,
 374                         &conf->mirrors[mirror].rdev->flags);
 375                 set_bit(R1BIO_WriteError, &r1_bio->state);
 376         } else {
 377                 /*
 378                  * Set R1BIO_Uptodate in our master bio, so that we
 379                  * will return a good error code for to the higher
 380                  * levels even if IO on some other mirrored buffer
 381                  * fails.
 382                  *
 383                  * The 'master' represents the composite IO operation
 384                  * to user-side. So if something waits for IO, then it
 385                  * will wait for the 'master' bio.
 386                  */
 387                 sector_t first_bad;
 388                 int bad_sectors;
 389
 390                 r1_bio->bios[mirror] = NULL;
 391                 to_put = bio;
 392                 set_bit(R1BIO_Uptodate, &r1_bio->state);
 393
 394                 /* Maybe we can clear some bad blocks. */
 395                 if (is_badblock(conf->mirrors[mirror].rdev,
 396                                 r1_bio->sector, r1_bio->sectors,
 397                                 &first_bad, &bad_sectors)) {
 398                         r1_bio->bios[mirror] = IO_MADE_GOOD;
 399                         set_bit(R1BIO_MadeGood, &r1_bio->state);
 400                 }
 401         }
 402
 403         update_head_pos(mirror, r1_bio);
 404
 405         if (behind) {
 406                 if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags))
 407                         atomic_dec(&r1_bio->behind_remaining);
 408
 409                 /*
 410                  * In behind mode, we ACK the master bio once the I/O
 411                  * has safely reached all non-writemostly
 412                  * disks. Setting the Returned bit ensures that this
 413                  * gets done only once -- we don't ever want to return
 414                  * -EIO here, instead we'll wait
 415                  */
 416                 if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
 417                     test_bit(R1BIO_Uptodate, &r1_bio->state)) {
 418                         /* Maybe we can return now */
 419                         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 420                                 struct bio *mbio = r1_bio->master_bio;
 421                                 PRINTK(KERN_DEBUG "raid1: behind end write sectors %llu-%llu\n",
 422                                        (unsigned long long) mbio->bi_sector,
 423                                        (unsigned long long) mbio->bi_sector +
 424                                        (mbio->bi_size >> 9) - 1);
 425                                 call_bio_endio(r1_bio);
 426                         }
 427                 }
 428         }
 429         if (r1_bio->bios[mirror] == NULL)
 430                 rdev_dec_pending(conf->mirrors[mirror].rdev,
 431                                  conf->mddev);
 432
 433         /*
 434          * Let's see if all mirrored write operations have finished
 435          * already.
 436          */
 437         r1_bio_write_done(r1_bio);
 438
 439         if (to_put)
 440                 bio_put(to_put);
 441 }
 442
 443
 444 /*
 445  * This routine returns the disk from which the requested read should
 446  * be done. There is a per-array 'next expected sequential IO' sector
 447  * number - if this matches on the next IO then we use the last disk.
 448  * There is also a per-disk 'last know head position' sector that is
 449  * maintained from IRQ contexts, both the normal and the resync IO
 450  * completion handlers update this position correctly. If there is no
 451  * perfect sequential match then we pick the disk whose head is closest.
 452  *
 453  * If there are 2 mirrors in the same 2 devices, performance degrades
 454  * because position is mirror, not device based.
 455  *
 456  * The rdev for the device selected will have nr_pending incremented.
 457  */
 458 static int read_balance(conf_t *conf, r1bio_t *r1_bio, int *max_sectors)
 459 {
 460         const sector_t this_sector = r1_bio->sector;
 461         int sectors;
 462         int best_good_sectors;
 463         int start_disk;
 464         int best_disk;
 465         int i;
 466         sector_t best_dist;
 467         mdk_rdev_t *rdev;
 468         int choose_first;
 469
 470         rcu_read_lock();
 471         /*
 472          * Check if we can balance. We can balance on the whole
 473          * device if no resync is going on, or below the resync window.
 474          * We take the first readable disk when above the resync window.
 475          */
 476  retry:
 477         sectors = r1_bio->sectors;
 478         best_disk = -1;
 479         best_dist = MaxSector;
 480         best_good_sectors = 0;
 481
 482         if (conf->mddev->recovery_cp < MaxSector &&
 483             (this_sector + sectors >= conf->next_resync)) {
 484                 choose_first = 1;
 485                 start_disk = 0;
 486         } else {
 487                 choose_first = 0;
 488                 start_disk = conf->last_used;
 489         }
 490
 491         for (i = 0 ; i < conf->raid_disks ; i++) {
 492                 sector_t dist;
 493                 sector_t first_bad;
 494                 int bad_sectors;
 495
 496                 int disk = start_disk + i;
 497                 if (disk >= conf->raid_disks)
 498                         disk -= conf->raid_disks;
 499
 500                 rdev = rcu_dereference(conf->mirrors[disk].rdev);
 501                 if (r1_bio->bios[disk] == IO_BLOCKED
 502                     || rdev == NULL
 503                     || test_bit(Faulty, &rdev->flags))
 504                         continue;
 505                 if (!test_bit(In_sync, &rdev->flags) &&
 506                     rdev->recovery_offset < this_sector + sectors)
 507                         continue;
 508                 if (test_bit(WriteMostly, &rdev->flags)) {
 509                         /* Don't balance among write-mostly, just
 510                          * use the first as a last resort */
 511                         if (best_disk < 0)
 512                                 best_disk = disk;
 513                         continue;
 514                 }
 515                 /* This is a reasonable device to use.  It might
 516                  * even be best.
 517                  */
 518                 if (is_badblock(rdev, this_sector, sectors,
 519                                 &first_bad, &bad_sectors)) {
 520                         if (best_dist < MaxSector)
 521                                 /* already have a better device */
 522                                 continue;
 523                         if (first_bad <= this_sector) {
 524                                 /* cannot read here. If this is the 'primary'
 525                                  * device, then we must not read beyond
 526                                  * bad_sectors from another device..
 527                                  */
 528                                 bad_sectors -= (this_sector - first_bad);
 529                                 if (choose_first && sectors > bad_sectors)
 530                                         sectors = bad_sectors;
 531                                 if (best_good_sectors > sectors)
 532                                         best_good_sectors = sectors;
 533
 534                         } else {
 535                                 sector_t good_sectors = first_bad - this_sector;
 536                                 if (good_sectors > best_good_sectors) {
 537                                         best_good_sectors = good_sectors;
 538                                         best_disk = disk;
 539                                 }
 540                                 if (choose_first)
 541                                         break;
 542                         }
 543                         continue;
 544                 } else
 545                         best_good_sectors = sectors;
 546
 547                 dist = abs(this_sector - conf->mirrors[disk].head_position);
 548                 if (choose_first
 549                     /* Don't change to another disk for sequential reads */
 550                     || conf->next_seq_sect == this_sector
 551                     || dist == 0
 552                     /* If device is idle, use it */
 553                     || atomic_read(&rdev->nr_pending) == 0) {
 554                         best_disk = disk;
 555                         break;
 556                 }
 557                 if (dist < best_dist) {
 558                         best_dist = dist;
 559                         best_disk = disk;
 560                 }
 561         }
 562
 563         if (best_disk >= 0) {
 564                 rdev = rcu_dereference(conf->mirrors[best_disk].rdev);
 565                 if (!rdev)
 566                         goto retry;
 567                 atomic_inc(&rdev->nr_pending);
 568                 if (test_bit(Faulty, &rdev->flags)) {
 569                         /* cannot risk returning a device that failed
 570                          * before we inc'ed nr_pending
 571                          */
 572                         rdev_dec_pending(rdev, conf->mddev);
 573                         goto retry;
 574                 }
 575                 sectors = best_good_sectors;
 576                 conf->next_seq_sect = this_sector + sectors;
 577                 conf->last_used = best_disk;
 578         }
 579         rcu_read_unlock();
 580         *max_sectors = sectors;
 581
 582         return best_disk;
 583 }
 584
 585 int md_raid1_congested(mddev_t *mddev, int bits)
 586 {
 587         conf_t *conf = mddev->private;
 588         int i, ret = 0;
 589
 590         rcu_read_lock();
 591         for (i = 0; i < mddev->raid_disks; i++) {
 592                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
 593                 if (rdev && !test_bit(Faulty, &rdev->flags)) {
 594                         struct request_queue *q = bdev_get_queue(rdev->bdev);
 595
 596                         BUG_ON(!q);
 597
 598                         /* Note the '|| 1' - when read_balance prefers
 599                          * non-congested targets, it can be removed
 600                          */
 601                         if ((bits & (1<<BDI_async_congested)) || 1)
 602                                 ret |= bdi_congested(&q->backing_dev_info, bits);
 603                         else
 604                                 ret &= bdi_congested(&q->backing_dev_info, bits);
 605                 }
 606         }
 607         rcu_read_unlock();
 608         return ret;
 609 }
 610 EXPORT_SYMBOL_GPL(md_raid1_congested);
 611
 612 static int raid1_congested(void *data, int bits)
 613 {
 614         mddev_t *mddev = data;
 615
 616         return mddev_congested(mddev, bits) ||
 617                 md_raid1_congested(mddev, bits);
 618 }
 619
 620 static void flush_pending_writes(conf_t *conf)
 621 {
 622         /* Any writes that have been queued but are awaiting
 623          * bitmap updates get flushed here.
 624          */
 625         spin_lock_irq(&conf->device_lock);
 626
 627         if (conf->pending_bio_list.head) {
 628                 struct bio *bio;
 629                 bio = bio_list_get(&conf->pending_bio_list);
 630                 spin_unlock_irq(&conf->device_lock);
 631                 /* flush any pending bitmap writes to
 632                  * disk before proceeding w/ I/O */
 633                 bitmap_unplug(conf->mddev->bitmap);
 634
 635                 while (bio) { /* submit pending writes */
 636                         struct bio *next = bio->bi_next;
 637                         bio->bi_next = NULL;
 638                         generic_make_request(bio);
 639                         bio = next;
 640                 }
 641         } else
 642                 spin_unlock_irq(&conf->device_lock);
 643 }
 644
 645 /* Barriers....
 646  * Sometimes we need to suspend IO while we do something else,
 647  * either some resync/recovery, or reconfigure the array.
 648  * To do this we raise a 'barrier'.
 649  * The 'barrier' is a counter that can be raised multiple times
 650  * to count how many activities are happening which preclude
 651  * normal IO.
 652  * We can only raise the barrier if there is no pending IO.
 653  * i.e. if nr_pending == 0.
 654  * We choose only to raise the barrier if no-one is waiting for the
 655  * barrier to go down.  This means that as soon as an IO request
 656  * is ready, no other operations which require a barrier will start
 657  * until the IO request has had a chance.
 658  *
 659  * So: regular IO calls 'wait_barrier'.  When that returns there
 660  *    is no backgroup IO happening,  It must arrange to call
 661  *    allow_barrier when it has finished its IO.
 662  * backgroup IO calls must call raise_barrier.  Once that returns
 663  *    there is no normal IO happeing.  It must arrange to call
 664  *    lower_barrier when the particular background IO completes.
 665  */
 666 #define RESYNC_DEPTH 32
 667
 668 static void raise_barrier(conf_t *conf)
 669 {
 670         spin_lock_irq(&conf->resync_lock);
 671
 672         /* Wait until no block IO is waiting */
 673         wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
 674                             conf->resync_lock, );
 675
 676         /* block any new IO from starting */
 677         conf->barrier++;
 678
 679         /* Now wait for all pending IO to complete */
 680         wait_event_lock_irq(conf->wait_barrier,
 681                             !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
 682                             conf->resync_lock, );
 683
 684         spin_unlock_irq(&conf->resync_lock);
 685 }
 686
 687 static void lower_barrier(conf_t *conf)
 688 {
 689         unsigned long flags;
 690         BUG_ON(conf->barrier <= 0);
 691         spin_lock_irqsave(&conf->resync_lock, flags);
 692         conf->barrier--;
 693         spin_unlock_irqrestore(&conf->resync_lock, flags);
 694         wake_up(&conf->wait_barrier);
 695 }
 696
 697 static void wait_barrier(conf_t *conf)
 698 {
 699         spin_lock_irq(&conf->resync_lock);
 700         if (conf->barrier) {
 701                 conf->nr_waiting++;
 702                 wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
 703                                     conf->resync_lock,
 704                                     );
 705                 conf->nr_waiting--;
 706         }
 707         conf->nr_pending++;
 708         spin_unlock_irq(&conf->resync_lock);
 709 }
 710
 711 static void allow_barrier(conf_t *conf)
 712 {
 713         unsigned long flags;
 714         spin_lock_irqsave(&conf->resync_lock, flags);
 715         conf->nr_pending--;
 716         spin_unlock_irqrestore(&conf->resync_lock, flags);
 717         wake_up(&conf->wait_barrier);
 718 }
 719
 720 static void freeze_array(conf_t *conf)
 721 {
 722         /* stop syncio and normal IO and wait for everything to
 723          * go quite.
 724          * We increment barrier and nr_waiting, and then
 725          * wait until nr_pending match nr_queued+1
 726          * This is called in the context of one normal IO request
 727          * that has failed. Thus any sync request that might be pending
 728          * will be blocked by nr_pending, and we need to wait for
 729          * pending IO requests to complete or be queued for re-try.
 730          * Thus the number queued (nr_queued) plus this request (1)
 731          * must match the number of pending IOs (nr_pending) before
 732          * we continue.
 733          */
 734         spin_lock_irq(&conf->resync_lock);
 735         conf->barrier++;
 736         conf->nr_waiting++;
 737         wait_event_lock_irq(conf->wait_barrier,
 738                             conf->nr_pending == conf->nr_queued+1,
 739                             conf->resync_lock,
 740                             flush_pending_writes(conf));
 741         spin_unlock_irq(&conf->resync_lock);
 742 }
 743 static void unfreeze_array(conf_t *conf)
 744 {
 745         /* reverse the effect of the freeze */
 746         spin_lock_irq(&conf->resync_lock);
 747         conf->barrier--;
 748         conf->nr_waiting--;
 749         wake_up(&conf->wait_barrier);
 750         spin_unlock_irq(&conf->resync_lock);
 751 }
 752
 753
 754 /* duplicate the data pages for behind I/O
 755  */
 756 static void alloc_behind_pages(struct bio *bio, r1bio_t *r1_bio)
 757 {
 758         int i;
 759         struct bio_vec *bvec;
 760         struct bio_vec *bvecs = kzalloc(bio->bi_vcnt * sizeof(struct bio_vec),
 761                                         GFP_NOIO);
 762         if (unlikely(!bvecs))
 763                 return;
 764
 765         bio_for_each_segment(bvec, bio, i) {
 766                 bvecs[i] = *bvec;
 767                 bvecs[i].bv_page = alloc_page(GFP_NOIO);
 768                 if (unlikely(!bvecs[i].bv_page))
 769                         goto do_sync_io;
 770                 memcpy(kmap(bvecs[i].bv_page) + bvec->bv_offset,
 771                        kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
 772                 kunmap(bvecs[i].bv_page);
 773                 kunmap(bvec->bv_page);
 774         }
 775         r1_bio->behind_bvecs = bvecs;
 776         r1_bio->behind_page_count = bio->bi_vcnt;
 777         set_bit(R1BIO_BehindIO, &r1_bio->state);
 778         return;
 779
 780 do_sync_io:
 781         for (i = 0; i < bio->bi_vcnt; i++)
 782                 if (bvecs[i].bv_page)
 783                         put_page(bvecs[i].bv_page);
 784         kfree(bvecs);
 785         PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
 786 }
 787
 788 static void make_request(mddev_t *mddev, struct bio * bio)
 789 {
 790         conf_t *conf = mddev->private;
 791         mirror_info_t *mirror;
 792         r1bio_t *r1_bio;
 793         struct bio *read_bio;
 794         int i, disks;
 795         struct bitmap *bitmap;
 796         unsigned long flags;
 797         const int rw = bio_data_dir(bio);
 798         const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
 799         const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA));
 800         mdk_rdev_t *blocked_rdev;
 801         int plugged;
 802         int first_clone;
 803         int sectors_handled;
 804         int max_sectors;
 805
 806         /*
 807          * Register the new request and wait if the reconstruction
 808          * thread has put up a bar for new requests.
 809          * Continue immediately if no resync is active currently.
 810          */
 811
 812         md_write_start(mddev, bio); /* wait on superblock update early */
 813
 814         if (bio_data_dir(bio) == WRITE &&
 815             bio->bi_sector + bio->bi_size/512 > mddev->suspend_lo &&
 816             bio->bi_sector < mddev->suspend_hi) {
 817                 /* As the suspend_* range is controlled by
 818                  * userspace, we want an interruptible
 819                  * wait.
 820                  */
 821                 DEFINE_WAIT(w);
 822                 for (;;) {
 823                         flush_signals(current);
 824                         prepare_to_wait(&conf->wait_barrier,
 825                                         &w, TASK_INTERRUPTIBLE);
 826                         if (bio->bi_sector + bio->bi_size/512 <= mddev->suspend_lo ||
 827                             bio->bi_sector >= mddev->suspend_hi)
 828                                 break;
 829                         schedule();
 830                 }
 831                 finish_wait(&conf->wait_barrier, &w);
 832         }
 833
 834         wait_barrier(conf);
 835
 836         bitmap = mddev->bitmap;
 837
 838         /*
 839          * make_request() can abort the operation when READA is being
 840          * used and no empty request is available.
 841          *
 842          */
 843         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
 844
 845         r1_bio->master_bio = bio;
 846         r1_bio->sectors = bio->bi_size >> 9;
 847         r1_bio->state = 0;
 848         r1_bio->mddev = mddev;
 849         r1_bio->sector = bio->bi_sector;
 850
 851         /* We might need to issue multiple reads to different
 852          * devices if there are bad blocks around, so we keep
 853          * track of the number of reads in bio->bi_phys_segments.
 854          * If this is 0, there is only one r1_bio and no locking
 855          * will be needed when requests complete.  If it is
 856          * non-zero, then it is the number of not-completed requests.
 857          */
 858         bio->bi_phys_segments = 0;
 859         clear_bit(BIO_SEG_VALID, &bio->bi_flags);
 860
 861         if (rw == READ) {
 862                 /*
 863                  * read balancing logic:
 864                  */
 865                 int rdisk;
 866
 867 read_again:
 868                 rdisk = read_balance(conf, r1_bio, &max_sectors);
 869
 870                 if (rdisk < 0) {
 871                         /* couldn't find anywhere to read from */
 872                         raid_end_bio_io(r1_bio);
 873                         return;
 874                 }
 875                 mirror = conf->mirrors + rdisk;
 876
 877                 if (test_bit(WriteMostly, &mirror->rdev->flags) &&
 878                     bitmap) {
 879                         /* Reading from a write-mostly device must
 880                          * take care not to over-take any writes
 881                          * that are 'behind'
 882                          */
 883                         wait_event(bitmap->behind_wait,
 884                                    atomic_read(&bitmap->behind_writes) == 0);
 885                 }
 886                 r1_bio->read_disk = rdisk;
 887
 888                 read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
 889                 md_trim_bio(read_bio, r1_bio->sector - bio->bi_sector,
 890                             max_sectors);
 891
 892                 r1_bio->bios[rdisk] = read_bio;
 893
 894                 read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
 895                 read_bio->bi_bdev = mirror->rdev->bdev;
 896                 read_bio->bi_end_io = raid1_end_read_request;
 897                 read_bio->bi_rw = READ | do_sync;
 898                 read_bio->bi_private = r1_bio;
 899
 900                 if (max_sectors < r1_bio->sectors) {
 901                         /* could not read all from this device, so we will
 902                          * need another r1_bio.
 903                          */
 904
 905                         sectors_handled = (r1_bio->sector + max_sectors
 906                                            - bio->bi_sector);
 907                         r1_bio->sectors = max_sectors;
 908                         spin_lock_irq(&conf->device_lock);
 909                         if (bio->bi_phys_segments == 0)
 910                                 bio->bi_phys_segments = 2;
 911                         else
 912                                 bio->bi_phys_segments++;
 913                         spin_unlock_irq(&conf->device_lock);
 914                         /* Cannot call generic_make_request directly
 915                          * as that will be queued in __make_request
 916                          * and subsequent mempool_alloc might block waiting
 917                          * for it.  So hand bio over to raid1d.
 918                          */
 919                         reschedule_retry(r1_bio);
 920
 921                         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
 922
 923                         r1_bio->master_bio = bio;
 924                         r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
 925                         r1_bio->state = 0;
 926                         r1_bio->mddev = mddev;
 927                         r1_bio->sector = bio->bi_sector + sectors_handled;
 928                         goto read_again;
 929                 } else
 930                         generic_make_request(read_bio);
 931                 return;
 932         }
 933
 934         /*
 935          * WRITE:
 936          */
 937         /* first select target devices under rcu_lock and
 938          * inc refcount on their rdev.  Record them by setting
 939          * bios[x] to bio
 940          * If there are known/acknowledged bad blocks on any device on
 941          * which we have seen a write error, we want to avoid writing those
 942          * blocks.
 943          * This potentially requires several writes to write around
 944          * the bad blocks.  Each set of writes gets it's own r1bio
 945          * with a set of bios attached.
 946          */
 947         plugged = mddev_check_plugged(mddev);
 948
 949         disks = conf->raid_disks;
 950  retry_write:
 951         blocked_rdev = NULL;
 952         rcu_read_lock();
 953         max_sectors = r1_bio->sectors;
 954         for (i = 0;  i < disks; i++) {
 955                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
 956                 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
 957                         atomic_inc(&rdev->nr_pending);
 958                         blocked_rdev = rdev;
 959                         break;
 960                 }
 961                 r1_bio->bios[i] = NULL;
 962                 if (!rdev || test_bit(Faulty, &rdev->flags)) {
 963                         set_bit(R1BIO_Degraded, &r1_bio->state);
 964                         continue;
 965                 }
 966
 967                 atomic_inc(&rdev->nr_pending);
 968                 if (test_bit(WriteErrorSeen, &rdev->flags)) {
 969                         sector_t first_bad;
 970                         int bad_sectors;
 971                         int is_bad;
 972
 973                         is_bad = is_badblock(rdev, r1_bio->sector,
 974                                              max_sectors,
 975                                              &first_bad, &bad_sectors);
 976                         if (is_bad < 0) {
 977                                 /* mustn't write here until the bad block is
 978                                  * acknowledged*/
 979                                 set_bit(BlockedBadBlocks, &rdev->flags);
 980                                 blocked_rdev = rdev;
 981                                 break;
 982                         }
 983                         if (is_bad && first_bad <= r1_bio->sector) {
 984                                 /* Cannot write here at all */
 985                                 bad_sectors -= (r1_bio->sector - first_bad);
 986                                 if (bad_sectors < max_sectors)
 987                                         /* mustn't write more than bad_sectors
 988                                          * to other devices yet
 989                                          */
 990                                         max_sectors = bad_sectors;
 991                                 rdev_dec_pending(rdev, mddev);
 992                                 /* We don't set R1BIO_Degraded as that
 993                                  * only applies if the disk is
 994                                  * missing, so it might be re-added,
 995                                  * and we want to know to recover this
 996                                  * chunk.
 997                                  * In this case the device is here,
 998                                  * and the fact that this chunk is not
 999                                  * in-sync is recorded in the bad
1000                                  * block log
1001                                  */
1002                                 continue;
1003                         }
1004                         if (is_bad) {
1005                                 int good_sectors = first_bad - r1_bio->sector;
1006                                 if (good_sectors < max_sectors)
1007                                         max_sectors = good_sectors;
1008                         }
1009                 }
1010                 r1_bio->bios[i] = bio;
1011         }
1012         rcu_read_unlock();
1013
1014         if (unlikely(blocked_rdev)) {
1015                 /* Wait for this device to become unblocked */
1016                 int j;
1017
1018                 for (j = 0; j < i; j++)
1019                         if (r1_bio->bios[j])
1020                                 rdev_dec_pending(conf->mirrors[j].rdev, mddev);
1021                 r1_bio->state = 0;
1022                 allow_barrier(conf);
1023                 md_wait_for_blocked_rdev(blocked_rdev, mddev);
1024                 wait_barrier(conf);
1025                 goto retry_write;
1026         }
1027
1028         if (max_sectors < r1_bio->sectors) {
1029                 /* We are splitting this write into multiple parts, so
1030                  * we need to prepare for allocating another r1_bio.
1031                  */
1032                 r1_bio->sectors = max_sectors;
1033                 spin_lock_irq(&conf->device_lock);
1034                 if (bio->bi_phys_segments == 0)
1035                         bio->bi_phys_segments = 2;
1036                 else
1037                         bio->bi_phys_segments++;
1038                 spin_unlock_irq(&conf->device_lock);
1039         }
1040         sectors_handled = r1_bio->sector + max_sectors - bio->bi_sector;
1041
1042         atomic_set(&r1_bio->remaining, 1);
1043         atomic_set(&r1_bio->behind_remaining, 0);
1044
1045         first_clone = 1;
1046         for (i = 0; i < disks; i++) {
1047                 struct bio *mbio;
1048                 if (!r1_bio->bios[i])
1049                         continue;
1050
1051                 mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1052                 md_trim_bio(mbio, r1_bio->sector - bio->bi_sector, max_sectors);
1053
1054                 if (first_clone) {
1055                         /* do behind I/O ?
1056                          * Not if there are too many, or cannot
1057                          * allocate memory, or a reader on WriteMostly
1058                          * is waiting for behind writes to flush */
1059                         if (bitmap &&
1060                             (atomic_read(&bitmap->behind_writes)
1061                              < mddev->bitmap_info.max_write_behind) &&
1062                             !waitqueue_active(&bitmap->behind_wait))
1063                                 alloc_behind_pages(mbio, r1_bio);
1064
1065                         bitmap_startwrite(bitmap, r1_bio->sector,
1066                                           r1_bio->sectors,
1067                                           test_bit(R1BIO_BehindIO,
1068                                                    &r1_bio->state));
1069                         first_clone = 0;
1070                 }
1071                 if (r1_bio->behind_bvecs) {
1072                         struct bio_vec *bvec;
1073                         int j;
1074
1075                         /* Yes, I really want the '__' version so that
1076                          * we clear any unused pointer in the io_vec, rather
1077                          * than leave them unchanged.  This is important
1078                          * because when we come to free the pages, we won't
1079                          * know the original bi_idx, so we just free
1080                          * them all
1081                          */
1082                         __bio_for_each_segment(bvec, mbio, j, 0)
1083                                 bvec->bv_page = r1_bio->behind_bvecs[j].bv_page;
1084                         if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
1085                                 atomic_inc(&r1_bio->behind_remaining);
1086                 }
1087
1088                 r1_bio->bios[i] = mbio;
1089
1090                 mbio->bi_sector = (r1_bio->sector +
1091                                    conf->mirrors[i].rdev->data_offset);
1092                 mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1093                 mbio->bi_end_io = raid1_end_write_request;
1094                 mbio->bi_rw = WRITE | do_flush_fua | do_sync;
1095                 mbio->bi_private = r1_bio;
1096
1097                 atomic_inc(&r1_bio->remaining);
1098                 spin_lock_irqsave(&conf->device_lock, flags);
1099                 bio_list_add(&conf->pending_bio_list, mbio);
1100                 spin_unlock_irqrestore(&conf->device_lock, flags);
1101         }
1102         /* Mustn't call r1_bio_write_done before this next test,
1103          * as it could result in the bio being freed.
1104          */
1105         if (sectors_handled < (bio->bi_size >> 9)) {
1106                 r1_bio_write_done(r1_bio);
1107                 /* We need another r1_bio.  It has already been counted
1108                  * in bio->bi_phys_segments
1109                  */
1110                 r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1111                 r1_bio->master_bio = bio;
1112                 r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
1113                 r1_bio->state = 0;
1114                 r1_bio->mddev = mddev;
1115                 r1_bio->sector = bio->bi_sector + sectors_handled;
1116                 goto retry_write;
1117         }
1118
1119         r1_bio_write_done(r1_bio);
1120
1121         /* In case raid1d snuck in to freeze_array */
1122         wake_up(&conf->wait_barrier);
1123
1124         if (do_sync || !bitmap || !plugged)
1125                 md_wakeup_thread(mddev->thread);
1126 }
1127
1128 static void status(struct seq_file *seq, mddev_t *mddev)
1129 {
1130         conf_t *conf = mddev->private;
1131         int i;
1132
1133         seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1134                    conf->raid_disks - mddev->degraded);
1135         rcu_read_lock();
1136         for (i = 0; i < conf->raid_disks; i++) {
1137                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1138                 seq_printf(seq, "%s",
1139                            rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1140         }
1141         rcu_read_unlock();
1142         seq_printf(seq, "]");
1143 }
1144
1145
1146 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
1147 {
1148         char b[BDEVNAME_SIZE];
1149         conf_t *conf = mddev->private;
1150
1151         /*
1152          * If it is not operational, then we have already marked it as dead
1153          * else if it is the last working disks, ignore the error, let the
1154          * next level up know.
1155          * else mark the drive as failed
1156          */
1157         if (test_bit(In_sync, &rdev->flags)
1158             && (conf->raid_disks - mddev->degraded) == 1) {
1159                 /*
1160                  * Don't fail the drive, act as though we were just a
1161                  * normal single drive.
1162                  * However don't try a recovery from this drive as
1163                  * it is very likely to fail.
1164                  */
1165                 conf->recovery_disabled = mddev->recovery_disabled;
1166                 return;
1167         }
1168         set_bit(Blocked, &rdev->flags);
1169         if (test_and_clear_bit(In_sync, &rdev->flags)) {
1170                 unsigned long flags;
1171                 spin_lock_irqsave(&conf->device_lock, flags);
1172                 mddev->degraded++;
1173                 set_bit(Faulty, &rdev->flags);
1174                 spin_unlock_irqrestore(&conf->device_lock, flags);
1175                 /*
1176                  * if recovery is running, make sure it aborts.
1177                  */
1178                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1179         } else
1180                 set_bit(Faulty, &rdev->flags);
1181         set_bit(MD_CHANGE_DEVS, &mddev->flags);
1182         printk(KERN_ALERT
1183                "md/raid1:%s: Disk failure on %s, disabling device.\n"
1184                "md/raid1:%s: Operation continuing on %d devices.\n",
1185                mdname(mddev), bdevname(rdev->bdev, b),
1186                mdname(mddev), conf->raid_disks - mddev->degraded);
1187 }
1188
1189 static void print_conf(conf_t *conf)
1190 {
1191         int i;
1192
1193         printk(KERN_DEBUG "RAID1 conf printout:\n");
1194         if (!conf) {
1195                 printk(KERN_DEBUG "(!conf)\n");
1196                 return;
1197         }
1198         printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1199                 conf->raid_disks);
1200
1201         rcu_read_lock();
1202         for (i = 0; i < conf->raid_disks; i++) {
1203                 char b[BDEVNAME_SIZE];
1204                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1205                 if (rdev)
1206                         printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
1207                                i, !test_bit(In_sync, &rdev->flags),
1208                                !test_bit(Faulty, &rdev->flags),
1209                                bdevname(rdev->bdev,b));
1210         }
1211         rcu_read_unlock();
1212 }
1213
1214 static void close_sync(conf_t *conf)
1215 {
1216         wait_barrier(conf);
1217         allow_barrier(conf);
1218
1219         mempool_destroy(conf->r1buf_pool);
1220         conf->r1buf_pool = NULL;
1221 }
1222
1223 static int raid1_spare_active(mddev_t *mddev)
1224 {
1225         int i;
1226         conf_t *conf = mddev->private;
1227         int count = 0;
1228         unsigned long flags;
1229
1230         /*
1231          * Find all failed disks within the RAID1 configuration
1232          * and mark them readable.
1233          * Called under mddev lock, so rcu protection not needed.
1234          */
1235         for (i = 0; i < conf->raid_disks; i++) {
1236                 mdk_rdev_t *rdev = conf->mirrors[i].rdev;
1237                 if (rdev
1238                     && !test_bit(Faulty, &rdev->flags)
1239                     && !test_and_set_bit(In_sync, &rdev->flags)) {
1240                         count++;
1241                         sysfs_notify_dirent_safe(rdev->sysfs_state);
1242                 }
1243         }
1244         spin_lock_irqsave(&conf->device_lock, flags);
1245         mddev->degraded -= count;
1246         spin_unlock_irqrestore(&conf->device_lock, flags);
1247
1248         print_conf(conf);
1249         return count;
1250 }
1251
1252
1253 static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
1254 {
1255         conf_t *conf = mddev->private;
1256         int err = -EEXIST;
1257         int mirror = 0;
1258         mirror_info_t *p;
1259         int first = 0;
1260         int last = mddev->raid_disks - 1;
1261
1262         if (mddev->recovery_disabled == conf->recovery_disabled)
1263                 return -EBUSY;
1264
1265         if (rdev->raid_disk >= 0)
1266                 first = last = rdev->raid_disk;
1267
1268         for (mirror = first; mirror <= last; mirror++)
1269                 if ( !(p=conf->mirrors+mirror)->rdev) {
1270
1271                         disk_stack_limits(mddev->gendisk, rdev->bdev,
1272                                           rdev->data_offset << 9);
1273                         /* as we don't honour merge_bvec_fn, we must
1274                          * never risk violating it, so limit
1275                          * ->max_segments to one lying with a single
1276                          * page, as a one page request is never in
1277                          * violation.
1278                          */
1279                         if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
1280                                 blk_queue_max_segments(mddev->queue, 1);
1281                                 blk_queue_segment_boundary(mddev->queue,
1282                                                            PAGE_CACHE_SIZE - 1);
1283                         }
1284
1285                         p->head_position = 0;
1286                         rdev->raid_disk = mirror;
1287                         err = 0;
1288                         /* As all devices are equivalent, we don't need a full recovery
1289                          * if this was recently any drive of the array
1290                          */
1291                         if (rdev->saved_raid_disk < 0)
1292                                 conf->fullsync = 1;
1293                         rcu_assign_pointer(p->rdev, rdev);
1294                         break;
1295                 }
1296         md_integrity_add_rdev(rdev, mddev);
1297         print_conf(conf);
1298         return err;
1299 }
1300
1301 static int raid1_remove_disk(mddev_t *mddev, int number)
1302 {
1303         conf_t *conf = mddev->private;
1304         int err = 0;
1305         mdk_rdev_t *rdev;
1306         mirror_info_t *p = conf->mirrors+ number;
1307
1308         print_conf(conf);
1309         rdev = p->rdev;
1310         if (rdev) {
1311                 if (test_bit(In_sync, &rdev->flags) ||
1312                     atomic_read(&rdev->nr_pending)) {
1313                         err = -EBUSY;
1314                         goto abort;
1315                 }
1316                 /* Only remove non-faulty devices if recovery
1317                  * is not possible.
1318                  */
1319                 if (!test_bit(Faulty, &rdev->flags) &&
1320                     mddev->recovery_disabled != conf->recovery_disabled &&
1321                     mddev->degraded < conf->raid_disks) {
1322                         err = -EBUSY;
1323                         goto abort;
1324                 }
1325                 p->rdev = NULL;
1326                 synchronize_rcu();
1327                 if (atomic_read(&rdev->nr_pending)) {
1328                         /* lost the race, try later */
1329                         err = -EBUSY;
1330                         p->rdev = rdev;
1331                         goto abort;
1332                 }
1333                 err = md_integrity_register(mddev);
1334         }
1335 abort:
1336
1337         print_conf(conf);
1338         return err;
1339 }
1340
1341
1342 static void end_sync_read(struct bio *bio, int error)
1343 {
1344         r1bio_t *r1_bio = bio->bi_private;
1345         int i;
1346
1347         for (i=r1_bio->mddev->raid_disks; i--; )
1348                 if (r1_bio->bios[i] == bio)
1349                         break;
1350         BUG_ON(i < 0);
1351         update_head_pos(i, r1_bio);
1352         /*
1353          * we have read a block, now it needs to be re-written,
1354          * or re-read if the read failed.
1355          * We don't do much here, just schedule handling by raid1d
1356          */
1357         if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1358                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1359
1360         if (atomic_dec_and_test(&r1_bio->remaining))
1361                 reschedule_retry(r1_bio);
1362 }
1363
1364 static void end_sync_write(struct bio *bio, int error)
1365 {
1366         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1367         r1bio_t *r1_bio = bio->bi_private;
1368         mddev_t *mddev = r1_bio->mddev;
1369         conf_t *conf = mddev->private;
1370         int i;
1371         int mirror=0;
1372         sector_t first_bad;
1373         int bad_sectors;
1374
1375         for (i = 0; i < conf->raid_disks; i++)
1376                 if (r1_bio->bios[i] == bio) {
1377                         mirror = i;
1378                         break;
1379                 }
1380         if (!uptodate) {
1381                 sector_t sync_blocks = 0;
1382                 sector_t s = r1_bio->sector;
1383                 long sectors_to_go = r1_bio->sectors;
1384                 /* make sure these bits doesn't get cleared. */
1385                 do {
1386                         bitmap_end_sync(mddev->bitmap, s,
1387                                         &sync_blocks, 1);
1388                         s += sync_blocks;
1389                         sectors_to_go -= sync_blocks;
1390                 } while (sectors_to_go > 0);
1391                 set_bit(WriteErrorSeen,
1392                         &conf->mirrors[mirror].rdev->flags);
1393                 set_bit(R1BIO_WriteError, &r1_bio->state);
1394         } else if (is_badblock(conf->mirrors[mirror].rdev,
1395                                r1_bio->sector,
1396                                r1_bio->sectors,
1397                                &first_bad, &bad_sectors) &&
1398                    !is_badblock(conf->mirrors[r1_bio->read_disk].rdev,
1399                                 r1_bio->sector,
1400                                 r1_bio->sectors,
1401                                 &first_bad, &bad_sectors)
1402                 )
1403                 set_bit(R1BIO_MadeGood, &r1_bio->state);
1404
1405         update_head_pos(mirror, r1_bio);
1406
1407         if (atomic_dec_and_test(&r1_bio->remaining)) {
1408                 int s = r1_bio->sectors;
1409                 if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
1410                     test_bit(R1BIO_WriteError, &r1_bio->state))
1411                         reschedule_retry(r1_bio);
1412                 else {
1413                         put_buf(r1_bio);
1414                         md_done_sync(mddev, s, uptodate);
1415                 }
1416         }
1417 }
1418
1419 static int r1_sync_page_io(mdk_rdev_t *rdev, sector_t sector,
1420                             int sectors, struct page *page, int rw)
1421 {
1422         if (sync_page_io(rdev, sector, sectors << 9, page, rw, false))
1423                 /* success */
1424                 return 1;
1425         if (rw == WRITE)
1426                 set_bit(WriteErrorSeen, &rdev->flags);
1427         /* need to record an error - either for the block or the device */
1428         if (!rdev_set_badblocks(rdev, sector, sectors, 0))
1429                 md_error(rdev->mddev, rdev);
1430         return 0;
1431 }
1432
1433 static int fix_sync_read_error(r1bio_t *r1_bio)
1434 {
1435         /* Try some synchronous reads of other devices to get
1436          * good data, much like with normal read errors.  Only
1437          * read into the pages we already have so we don't
1438          * need to re-issue the read request.
1439          * We don't need to freeze the array, because being in an
1440          * active sync request, there is no normal IO, and
1441          * no overlapping syncs.
1442          * We don't need to check is_badblock() again as we
1443          * made sure that anything with a bad block in range
1444          * will have bi_end_io clear.
1445          */
1446         mddev_t *mddev = r1_bio->mddev;
1447         conf_t *conf = mddev->private;
1448         struct bio *bio = r1_bio->bios[r1_bio->read_disk];
1449         sector_t sect = r1_bio->sector;
1450         int sectors = r1_bio->sectors;
1451         int idx = 0;
1452
1453         while(sectors) {
1454                 int s = sectors;
1455                 int d = r1_bio->read_disk;
1456                 int success = 0;
1457                 mdk_rdev_t *rdev;
1458                 int start;
1459
1460                 if (s > (PAGE_SIZE>>9))
1461                         s = PAGE_SIZE >> 9;
1462                 do {
1463                         if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1464                                 /* No rcu protection needed here devices
1465                                  * can only be removed when no resync is
1466                                  * active, and resync is currently active
1467                                  */
1468                                 rdev = conf->mirrors[d].rdev;
1469                                 if (sync_page_io(rdev, sect, s<<9,
1470                                                  bio->bi_io_vec[idx].bv_page,
1471                                                  READ, false)) {
1472                                         success = 1;
1473                                         break;
1474                                 }
1475                         }
1476                         d++;
1477                         if (d == conf->raid_disks)
1478                                 d = 0;
1479                 } while (!success && d != r1_bio->read_disk);
1480
1481                 if (!success) {
1482                         char b[BDEVNAME_SIZE];
1483                         int abort = 0;
1484                         /* Cannot read from anywhere, this block is lost.
1485                          * Record a bad block on each device.  If that doesn't
1486                          * work just disable and interrupt the recovery.
1487                          * Don't fail devices as that won't really help.
1488                          */
1489                         printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O read error"
1490                                " for block %llu\n",
1491                                mdname(mddev),
1492                                bdevname(bio->bi_bdev, b),
1493                                (unsigned long long)r1_bio->sector);
1494                         for (d = 0; d < conf->raid_disks; d++) {
1495                                 rdev = conf->mirrors[d].rdev;
1496                                 if (!rdev || test_bit(Faulty, &rdev->flags))
1497                                         continue;
1498                                 if (!rdev_set_badblocks(rdev, sect, s, 0))
1499                                         abort = 1;
1500                         }
1501                         if (abort) {
1502                                 mddev->recovery_disabled = 1;
1503                                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1504                                 md_done_sync(mddev, r1_bio->sectors, 0);
1505                                 put_buf(r1_bio);
1506                                 return 0;
1507                         }
1508                         /* Try next page */
1509                         sectors -= s;
1510                         sect += s;
1511                         idx++;
1512                         continue;
1513                 }
1514
1515                 start = d;
1516                 /* write it back and re-read */
1517                 while (d != r1_bio->read_disk) {
1518                         if (d == 0)
1519                                 d = conf->raid_disks;
1520                         d--;
1521                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1522                                 continue;
1523                         rdev = conf->mirrors[d].rdev;
1524                         if (r1_sync_page_io(rdev, sect, s,
1525                                             bio->bi_io_vec[idx].bv_page,
1526                                             WRITE) == 0) {
1527                                 r1_bio->bios[d]->bi_end_io = NULL;
1528                                 rdev_dec_pending(rdev, mddev);
1529                         }
1530                 }
1531                 d = start;
1532                 while (d != r1_bio->read_disk) {
1533                         if (d == 0)
1534                                 d = conf->raid_disks;
1535                         d--;
1536                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1537                                 continue;
1538                         rdev = conf->mirrors[d].rdev;
1539                         if (r1_sync_page_io(rdev, sect, s,
1540                                             bio->bi_io_vec[idx].bv_page,
1541                                             READ) != 0)
1542                                 atomic_add(s, &rdev->corrected_errors);
1543                 }
1544                 sectors -= s;
1545                 sect += s;
1546                 idx ++;
1547         }
1548         set_bit(R1BIO_Uptodate, &r1_bio->state);
1549         set_bit(BIO_UPTODATE, &bio->bi_flags);
1550         return 1;
1551 }
1552
1553 static int process_checks(r1bio_t *r1_bio)
1554 {
1555         /* We have read all readable devices.  If we haven't
1556          * got the block, then there is no hope left.
1557          * If we have, then we want to do a comparison
1558          * and skip the write if everything is the same.
1559          * If any blocks failed to read, then we need to
1560          * attempt an over-write
1561          */
1562         mddev_t *mddev = r1_bio->mddev;
1563         conf_t *conf = mddev->private;
1564         int primary;
1565         int i;
1566
1567         for (primary = 0; primary < conf->raid_disks; primary++)
1568                 if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1569                     test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
1570                         r1_bio->bios[primary]->bi_end_io = NULL;
1571                         rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1572                         break;
1573                 }
1574         r1_bio->read_disk = primary;
1575         for (i = 0; i < conf->raid_disks; i++) {
1576                 int j;
1577                 int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
1578                 struct bio *pbio = r1_bio->bios[primary];
1579                 struct bio *sbio = r1_bio->bios[i];
1580                 int size;
1581
1582                 if (r1_bio->bios[i]->bi_end_io != end_sync_read)
1583                         continue;
1584
1585                 if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
1586                         for (j = vcnt; j-- ; ) {
1587                                 struct page *p, *s;
1588                                 p = pbio->bi_io_vec[j].bv_page;
1589                                 s = sbio->bi_io_vec[j].bv_page;
1590                                 if (memcmp(page_address(p),
1591                                            page_address(s),
1592                                            PAGE_SIZE))
1593                                         break;
1594                         }
1595                 } else
1596                         j = 0;
1597                 if (j >= 0)
1598                         mddev->resync_mismatches += r1_bio->sectors;
1599                 if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
1600                               && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
1601                         /* No need to write to this device. */
1602                         sbio->bi_end_io = NULL;
1603                         rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1604                         continue;
1605                 }
1606                 /* fixup the bio for reuse */
1607                 sbio->bi_vcnt = vcnt;
1608                 sbio->bi_size = r1_bio->sectors << 9;
1609                 sbio->bi_idx = 0;
1610                 sbio->bi_phys_segments = 0;
1611                 sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1612                 sbio->bi_flags |= 1 << BIO_UPTODATE;
1613                 sbio->bi_next = NULL;
1614                 sbio->bi_sector = r1_bio->sector +
1615                         conf->mirrors[i].rdev->data_offset;
1616                 sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1617                 size = sbio->bi_size;
1618                 for (j = 0; j < vcnt ; j++) {
1619                         struct bio_vec *bi;
1620                         bi = &sbio->bi_io_vec[j];
1621                         bi->bv_offset = 0;
1622                         if (size > PAGE_SIZE)
1623                                 bi->bv_len = PAGE_SIZE;
1624                         else
1625                                 bi->bv_len = size;
1626                         size -= PAGE_SIZE;
1627                         memcpy(page_address(bi->bv_page),
1628                                page_address(pbio->bi_io_vec[j].bv_page),
1629                                PAGE_SIZE);
1630                 }
1631         }
1632         return 0;
1633 }
1634
1635 static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
1636 {
1637         conf_t *conf = mddev->private;
1638         int i;
1639         int disks = conf->raid_disks;
1640         struct bio *bio, *wbio;
1641
1642         bio = r1_bio->bios[r1_bio->read_disk];
1643
1644         if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
1645                 /* ouch - failed to read all of that. */
1646                 if (!fix_sync_read_error(r1_bio))
1647                         return;
1648
1649         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1650                 if (process_checks(r1_bio) < 0)
1651                         return;
1652         /*
1653          * schedule writes
1654          */
1655         atomic_set(&r1_bio->remaining, 1);
1656         for (i = 0; i < disks ; i++) {
1657                 wbio = r1_bio->bios[i];
1658                 if (wbio->bi_end_io == NULL ||
1659                     (wbio->bi_end_io == end_sync_read &&
1660                      (i == r1_bio->read_disk ||
1661                       !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
1662                         continue;
1663
1664                 wbio->bi_rw = WRITE;
1665                 wbio->bi_end_io = end_sync_write;
1666                 atomic_inc(&r1_bio->remaining);
1667                 md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1668
1669                 generic_make_request(wbio);
1670         }
1671
1672         if (atomic_dec_and_test(&r1_bio->remaining)) {
1673                 /* if we're here, all write(s) have completed, so clean up */
1674                 md_done_sync(mddev, r1_bio->sectors, 1);
1675                 put_buf(r1_bio);
1676         }
1677 }
1678
1679 /*
1680  * This is a kernel thread which:
1681  *
1682  *      1.      Retries failed read operations on working mirrors.
1683  *      2.      Updates the raid superblock when problems encounter.
1684  *      3.      Performs writes following reads for array synchronising.
1685  */
1686
1687 static void fix_read_error(conf_t *conf, int read_disk,
1688                            sector_t sect, int sectors)
1689 {
1690         mddev_t *mddev = conf->mddev;
1691         while(sectors) {
1692                 int s = sectors;
1693                 int d = read_disk;
1694                 int success = 0;
1695                 int start;
1696                 mdk_rdev_t *rdev;
1697
1698                 if (s > (PAGE_SIZE>>9))
1699                         s = PAGE_SIZE >> 9;
1700
1701                 do {
1702                         /* Note: no rcu protection needed here
1703                          * as this is synchronous in the raid1d thread
1704                          * which is the thread that might remove
1705                          * a device.  If raid1d ever becomes multi-threaded....
1706                          */
1707                         sector_t first_bad;
1708                         int bad_sectors;
1709
1710                         rdev = conf->mirrors[d].rdev;
1711                         if (rdev &&
1712                             test_bit(In_sync, &rdev->flags) &&
1713                             is_badblock(rdev, sect, s,
1714                                         &first_bad, &bad_sectors) == 0 &&
1715                             sync_page_io(rdev, sect, s<<9,
1716                                          conf->tmppage, READ, false))
1717                                 success = 1;
1718                         else {
1719                                 d++;
1720                                 if (d == conf->raid_disks)
1721                                         d = 0;
1722                         }
1723                 } while (!success && d != read_disk);
1724
1725                 if (!success) {
1726                         /* Cannot read from anywhere - mark it bad */
1727                         mdk_rdev_t *rdev = conf->mirrors[read_disk].rdev;
1728                         if (!rdev_set_badblocks(rdev, sect, s, 0))
1729                                 md_error(mddev, rdev);
1730                         break;
1731                 }
1732                 /* write it back and re-read */
1733                 start = d;
1734                 while (d != read_disk) {
1735                         if (d==0)
1736                                 d = conf->raid_disks;
1737                         d--;
1738                         rdev = conf->mirrors[d].rdev;
1739                         if (rdev &&
1740                             test_bit(In_sync, &rdev->flags))
1741                                 r1_sync_page_io(rdev, sect, s,
1742                                                 conf->tmppage, WRITE);
1743                 }
1744                 d = start;
1745                 while (d != read_disk) {
1746                         char b[BDEVNAME_SIZE];
1747                         if (d==0)
1748                                 d = conf->raid_disks;
1749                         d--;
1750                         rdev = conf->mirrors[d].rdev;
1751                         if (rdev &&
1752                             test_bit(In_sync, &rdev->flags)) {
1753                                 if (r1_sync_page_io(rdev, sect, s,
1754                                                     conf->tmppage, READ)) {
1755                                         atomic_add(s, &rdev->corrected_errors);
1756                                         printk(KERN_INFO
1757                                                "md/raid1:%s: read error corrected "
1758                                                "(%d sectors at %llu on %s)\n",
1759                                                mdname(mddev), s,
1760                                                (unsigned long long)(sect +
1761                                                    rdev->data_offset),
1762                                                bdevname(rdev->bdev, b));
1763                                 }
1764                         }
1765                 }
1766                 sectors -= s;
1767                 sect += s;
1768         }
1769 }
1770
1771 static void bi_complete(struct bio *bio, int error)
1772 {
1773         complete((struct completion *)bio->bi_private);
1774 }
1775
1776 static int submit_bio_wait(int rw, struct bio *bio)
1777 {
1778         struct completion event;
1779         rw |= REQ_SYNC;
1780
1781         init_completion(&event);
1782         bio->bi_private = &event;
1783         bio->bi_end_io = bi_complete;
1784         submit_bio(rw, bio);
1785         wait_for_completion(&event);
1786
1787         return test_bit(BIO_UPTODATE, &bio->bi_flags);
1788 }
1789
1790 static int narrow_write_error(r1bio_t *r1_bio, int i)
1791 {
1792         mddev_t *mddev = r1_bio->mddev;
1793         conf_t *conf = mddev->private;
1794         mdk_rdev_t *rdev = conf->mirrors[i].rdev;
1795         int vcnt, idx;
1796         struct bio_vec *vec;
1797
1798         /* bio has the data to be written to device 'i' where
1799          * we just recently had a write error.
1800          * We repeatedly clone the bio and trim down to one block,
1801          * then try the write.  Where the write fails we record
1802          * a bad block.
1803          * It is conceivable that the bio doesn't exactly align with
1804          * blocks.  We must handle this somehow.
1805          *
1806          * We currently own a reference on the rdev.
1807          */
1808
1809         int block_sectors;
1810         sector_t sector;
1811         int sectors;
1812         int sect_to_write = r1_bio->sectors;
1813         int ok = 1;
1814
1815         if (rdev->badblocks.shift < 0)
1816                 return 0;
1817
1818         block_sectors = 1 << rdev->badblocks.shift;
1819         sector = r1_bio->sector;
1820         sectors = ((sector + block_sectors)
1821                    & ~(sector_t)(block_sectors - 1))
1822                 - sector;
1823
1824         if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
1825                 vcnt = r1_bio->behind_page_count;
1826                 vec = r1_bio->behind_bvecs;
1827                 idx = 0;
1828                 while (vec[idx].bv_page == NULL)
1829                         idx++;
1830         } else {
1831                 vcnt = r1_bio->master_bio->bi_vcnt;
1832                 vec = r1_bio->master_bio->bi_io_vec;
1833                 idx = r1_bio->master_bio->bi_idx;
1834         }
1835         while (sect_to_write) {
1836                 struct bio *wbio;
1837                 if (sectors > sect_to_write)
1838                         sectors = sect_to_write;
1839                 /* Write at 'sector' for 'sectors'*/
1840
1841                 wbio = bio_alloc_mddev(GFP_NOIO, vcnt, mddev);
1842                 memcpy(wbio->bi_io_vec, vec, vcnt * sizeof(struct bio_vec));
1843                 wbio->bi_sector = r1_bio->sector;
1844                 wbio->bi_rw = WRITE;
1845                 wbio->bi_vcnt = vcnt;
1846                 wbio->bi_size = r1_bio->sectors << 9;
1847                 wbio->bi_idx = idx;
1848
1849                 md_trim_bio(wbio, sector - r1_bio->sector, sectors);
1850                 wbio->bi_sector += rdev->data_offset;
1851                 wbio->bi_bdev = rdev->bdev;
1852                 if (submit_bio_wait(WRITE, wbio) == 0)
1853                         /* failure! */
1854                         ok = rdev_set_badblocks(rdev, sector,
1855                                                 sectors, 0)
1856                                 && ok;
1857
1858                 bio_put(wbio);
1859                 sect_to_write -= sectors;
1860                 sector += sectors;
1861                 sectors = block_sectors;
1862         }
1863         return ok;
1864 }
1865
1866 static void handle_sync_write_finished(conf_t *conf, r1bio_t *r1_bio)
1867 {
1868         int m;
1869         int s = r1_bio->sectors;
1870         for (m = 0; m < conf->raid_disks ; m++) {
1871                 mdk_rdev_t *rdev = conf->mirrors[m].rdev;
1872                 struct bio *bio = r1_bio->bios[m];
1873                 if (bio->bi_end_io == NULL)
1874                         continue;
1875                 if (test_bit(BIO_UPTODATE, &bio->bi_flags) &&
1876                     test_bit(R1BIO_MadeGood, &r1_bio->state)) {
1877                         rdev_clear_badblocks(rdev, r1_bio->sector, s);
1878                 }
1879                 if (!test_bit(BIO_UPTODATE, &bio->bi_flags) &&
1880                     test_bit(R1BIO_WriteError, &r1_bio->state)) {
1881                         if (!rdev_set_badblocks(rdev, r1_bio->sector, s, 0))
1882                                 md_error(conf->mddev, rdev);
1883                 }
1884         }
1885         put_buf(r1_bio);
1886         md_done_sync(conf->mddev, s, 1);
1887 }
1888
1889 static void handle_write_finished(conf_t *conf, r1bio_t *r1_bio)
1890 {
1891         int m;
1892         for (m = 0; m < conf->raid_disks ; m++)
1893                 if (r1_bio->bios[m] == IO_MADE_GOOD) {
1894                         mdk_rdev_t *rdev = conf->mirrors[m].rdev;
1895                         rdev_clear_badblocks(rdev,
1896                                              r1_bio->sector,
1897                                              r1_bio->sectors);
1898                         rdev_dec_pending(rdev, conf->mddev);
1899                 } else if (r1_bio->bios[m] != NULL) {
1900                         /* This drive got a write error.  We need to
1901                          * narrow down and record precise write
1902                          * errors.
1903                          */
1904                         if (!narrow_write_error(r1_bio, m)) {
1905                                 md_error(conf->mddev,
1906                                          conf->mirrors[m].rdev);
1907                                 /* an I/O failed, we can't clear the bitmap */
1908                                 set_bit(R1BIO_Degraded, &r1_bio->state);
1909                         }
1910                         rdev_dec_pending(conf->mirrors[m].rdev,
1911                                          conf->mddev);
1912                 }
1913         if (test_bit(R1BIO_WriteError, &r1_bio->state))
1914                 close_write(r1_bio);
1915         raid_end_bio_io(r1_bio);
1916 }
1917
1918 static void handle_read_error(conf_t *conf, r1bio_t *r1_bio)
1919 {
1920         int disk;
1921         int max_sectors;
1922         mddev_t *mddev = conf->mddev;
1923         struct bio *bio;
1924         char b[BDEVNAME_SIZE];
1925         mdk_rdev_t *rdev;
1926
1927         clear_bit(R1BIO_ReadError, &r1_bio->state);
1928         /* we got a read error. Maybe the drive is bad.  Maybe just
1929          * the block and we can fix it.
1930          * We freeze all other IO, and try reading the block from
1931          * other devices.  When we find one, we re-write
1932          * and check it that fixes the read error.
1933          * This is all done synchronously while the array is
1934          * frozen
1935          */
1936         if (mddev->ro == 0) {
1937                 freeze_array(conf);
1938                 fix_read_error(conf, r1_bio->read_disk,
1939                                r1_bio->sector, r1_bio->sectors);
1940                 unfreeze_array(conf);
1941         } else
1942                 md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
1943
1944         bio = r1_bio->bios[r1_bio->read_disk];
1945         bdevname(bio->bi_bdev, b);
1946 read_more:
1947         disk = read_balance(conf, r1_bio, &max_sectors);
1948         if (disk == -1) {
1949                 printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O"
1950                        " read error for block %llu\n",
1951                        mdname(mddev), b, (unsigned long long)r1_bio->sector);
1952                 raid_end_bio_io(r1_bio);
1953         } else {
1954                 const unsigned long do_sync
1955                         = r1_bio->master_bio->bi_rw & REQ_SYNC;
1956                 if (bio) {
1957                         r1_bio->bios[r1_bio->read_disk] =
1958                                 mddev->ro ? IO_BLOCKED : NULL;
1959                         bio_put(bio);
1960                 }
1961                 r1_bio->read_disk = disk;
1962                 bio = bio_clone_mddev(r1_bio->master_bio, GFP_NOIO, mddev);
1963                 md_trim_bio(bio, r1_bio->sector - bio->bi_sector, max_sectors);
1964                 r1_bio->bios[r1_bio->read_disk] = bio;
1965                 rdev = conf->mirrors[disk].rdev;
1966                 printk_ratelimited(KERN_ERR
1967                                    "md/raid1:%s: redirecting sector %llu"
1968                                    " to other mirror: %s\n",
1969                                    mdname(mddev),
1970                                    (unsigned long long)r1_bio->sector,
1971                                    bdevname(rdev->bdev, b));
1972                 bio->bi_sector = r1_bio->sector + rdev->data_offset;
1973                 bio->bi_bdev = rdev->bdev;
1974                 bio->bi_end_io = raid1_end_read_request;
1975                 bio->bi_rw = READ | do_sync;
1976                 bio->bi_private = r1_bio;
1977                 if (max_sectors < r1_bio->sectors) {
1978                         /* Drat - have to split this up more */
1979                         struct bio *mbio = r1_bio->master_bio;
1980                         int sectors_handled = (r1_bio->sector + max_sectors
1981                                                - mbio->bi_sector);
1982                         r1_bio->sectors = max_sectors;
1983                         spin_lock_irq(&conf->device_lock);
1984                         if (mbio->bi_phys_segments == 0)
1985                                 mbio->bi_phys_segments = 2;
1986                         else
1987                                 mbio->bi_phys_segments++;
1988                         spin_unlock_irq(&conf->device_lock);
1989                         generic_make_request(bio);
1990                         bio = NULL;
1991
1992                         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1993
1994                         r1_bio->master_bio = mbio;
1995                         r1_bio->sectors = (mbio->bi_size >> 9)
1996                                           - sectors_handled;
1997                         r1_bio->state = 0;
1998                         set_bit(R1BIO_ReadError, &r1_bio->state);
1999                         r1_bio->mddev = mddev;
2000                         r1_bio->sector = mbio->bi_sector + sectors_handled;
2001
2002                         goto read_more;
2003                 } else
2004                         generic_make_request(bio);
2005         }
2006 }
2007
2008 static void raid1d(mddev_t *mddev)
2009 {
2010         r1bio_t *r1_bio;
2011         unsigned long flags;
2012         conf_t *conf = mddev->private;
2013         struct list_head *head = &conf->retry_list;
2014         struct blk_plug plug;
2015
2016         md_check_recovery(mddev);
2017
2018         blk_start_plug(&plug);
2019         for (;;) {
2020
2021                 if (atomic_read(&mddev->plug_cnt) == 0)
2022                         flush_pending_writes(conf);
2023
2024                 spin_lock_irqsave(&conf->device_lock, flags);
2025                 if (list_empty(head)) {
2026                         spin_unlock_irqrestore(&conf->device_lock, flags);
2027                         break;
2028                 }
2029                 r1_bio = list_entry(head->prev, r1bio_t, retry_list);
2030                 list_del(head->prev);
2031                 conf->nr_queued--;
2032                 spin_unlock_irqrestore(&conf->device_lock, flags);
2033
2034                 mddev = r1_bio->mddev;
2035                 conf = mddev->private;
2036                 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
2037                         if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2038                             test_bit(R1BIO_WriteError, &r1_bio->state))
2039                                 handle_sync_write_finished(conf, r1_bio);
2040                         else
2041                                 sync_request_write(mddev, r1_bio);
2042                 } else if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2043                            test_bit(R1BIO_WriteError, &r1_bio->state))
2044                         handle_write_finished(conf, r1_bio);
2045                 else if (test_bit(R1BIO_ReadError, &r1_bio->state))
2046                         handle_read_error(conf, r1_bio);
2047                 else
2048                         /* just a partial read to be scheduled from separate
2049                          * context
2050                          */
2051                         generic_make_request(r1_bio->bios[r1_bio->read_disk]);
2052
2053                 cond_resched();
2054                 if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
2055                         md_check_recovery(mddev);
2056         }
2057         blk_finish_plug(&plug);
2058 }
2059
2060
2061 static int init_resync(conf_t *conf)
2062 {
2063         int buffs;
2064
2065         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
2066         BUG_ON(conf->r1buf_pool);
2067         conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
2068                                           conf->poolinfo);
2069         if (!conf->r1buf_pool)
2070                 return -ENOMEM;
2071         conf->next_resync = 0;
2072         return 0;
2073 }
2074
2075 /*
2076  * perform a "sync" on one "block"
2077  *
2078  * We need to make sure that no normal I/O request - particularly write
2079  * requests - conflict with active sync requests.
2080  *
2081  * This is achieved by tracking pending requests and a 'barrier' concept
2082  * that can be installed to exclude normal IO requests.
2083  */
2084
2085 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
2086 {
2087         conf_t *conf = mddev->private;
2088         r1bio_t *r1_bio;
2089         struct bio *bio;
2090         sector_t max_sector, nr_sectors;
2091         int disk = -1;
2092         int i;
2093         int wonly = -1;
2094         int write_targets = 0, read_targets = 0;
2095         sector_t sync_blocks;
2096         int still_degraded = 0;
2097         int good_sectors = RESYNC_SECTORS;
2098         int min_bad = 0; /* number of sectors that are bad in all devices */
2099
2100         if (!conf->r1buf_pool)
2101                 if (init_resync(conf))
2102                         return 0;
2103
2104         max_sector = mddev->dev_sectors;
2105         if (sector_nr >= max_sector) {
2106                 /* If we aborted, we need to abort the
2107                  * sync on the 'current' bitmap chunk (there will
2108                  * only be one in raid1 resync.
2109                  * We can find the current addess in mddev->curr_resync
2110                  */
2111                 if (mddev->curr_resync < max_sector) /* aborted */
2112                         bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
2113                                                 &sync_blocks, 1);
2114                 else /* completed sync */
2115                         conf->fullsync = 0;
2116
2117                 bitmap_close_sync(mddev->bitmap);
2118                 close_sync(conf);
2119                 return 0;
2120         }
2121
2122         if (mddev->bitmap == NULL &&
2123             mddev->recovery_cp == MaxSector &&
2124             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
2125             conf->fullsync == 0) {
2126                 *skipped = 1;
2127                 return max_sector - sector_nr;
2128         }
2129         /* before building a request, check if we can skip these blocks..
2130          * This call the bitmap_start_sync doesn't actually record anything
2131          */
2132         if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
2133             !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2134                 /* We can skip this block, and probably several more */
2135                 *skipped = 1;
2136                 return sync_blocks;
2137         }
2138         /*
2139          * If there is non-resync activity waiting for a turn,
2140          * and resync is going fast enough,
2141          * then let it though before starting on this new sync request.
2142          */
2143         if (!go_faster && conf->nr_waiting)
2144                 msleep_interruptible(1000);
2145
2146         bitmap_cond_end_sync(mddev->bitmap, sector_nr);
2147         r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
2148         raise_barrier(conf);
2149
2150         conf->next_resync = sector_nr;
2151
2152         rcu_read_lock();
2153         /*
2154          * If we get a correctably read error during resync or recovery,
2155          * we might want to read from a different device.  So we
2156          * flag all drives that could conceivably be read from for READ,
2157          * and any others (which will be non-In_sync devices) for WRITE.
2158          * If a read fails, we try reading from something else for which READ
2159          * is OK.
2160          */
2161
2162         r1_bio->mddev = mddev;
2163         r1_bio->sector = sector_nr;
2164         r1_bio->state = 0;
2165         set_bit(R1BIO_IsSync, &r1_bio->state);
2166
2167         for (i=0; i < conf->raid_disks; i++) {
2168                 mdk_rdev_t *rdev;
2169                 bio = r1_bio->bios[i];
2170
2171                 /* take from bio_init */
2172                 bio->bi_next = NULL;
2173                 bio->bi_flags &= ~(BIO_POOL_MASK-1);
2174                 bio->bi_flags |= 1 << BIO_UPTODATE;
2175                 bio->bi_rw = READ;
2176                 bio->bi_vcnt = 0;
2177                 bio->bi_idx = 0;
2178                 bio->bi_phys_segments = 0;
2179                 bio->bi_size = 0;
2180                 bio->bi_end_io = NULL;
2181                 bio->bi_private = NULL;
2182
2183                 rdev = rcu_dereference(conf->mirrors[i].rdev);
2184                 if (rdev == NULL ||
2185                     test_bit(Faulty, &rdev->flags)) {
2186                         still_degraded = 1;
2187                 } else if (!test_bit(In_sync, &rdev->flags)) {
2188                         bio->bi_rw = WRITE;
2189                         bio->bi_end_io = end_sync_write;
2190                         write_targets ++;
2191                 } else {
2192                         /* may need to read from here */
2193                         sector_t first_bad = MaxSector;
2194                         int bad_sectors;
2195
2196                         if (is_badblock(rdev, sector_nr, good_sectors,
2197                                         &first_bad, &bad_sectors)) {
2198                                 if (first_bad > sector_nr)
2199                                         good_sectors = first_bad - sector_nr;
2200                                 else {
2201                                         bad_sectors -= (sector_nr - first_bad);
2202                                         if (min_bad == 0 ||
2203                                             min_bad > bad_sectors)
2204                                                 min_bad = bad_sectors;
2205                                 }
2206                         }
2207                         if (sector_nr < first_bad) {
2208                                 if (test_bit(WriteMostly, &rdev->flags)) {
2209                                         if (wonly < 0)
2210                                                 wonly = i;
2211                                 } else {
2212                                         if (disk < 0)
2213                                                 disk = i;
2214                                 }
2215                                 bio->bi_rw = READ;
2216                                 bio->bi_end_io = end_sync_read;
2217                                 read_targets++;
2218                         }
2219                 }
2220                 if (bio->bi_end_io) {
2221                         atomic_inc(&rdev->nr_pending);
2222                         bio->bi_sector = sector_nr + rdev->data_offset;
2223                         bio->bi_bdev = rdev->bdev;
2224                         bio->bi_private = r1_bio;
2225                 }
2226         }
2227         rcu_read_unlock();
2228         if (disk < 0)
2229                 disk = wonly;
2230         r1_bio->read_disk = disk;
2231
2232         if (read_targets == 0 && min_bad > 0) {
2233                 /* These sectors are bad on all InSync devices, so we
2234                  * need to mark them bad on all write targets
2235                  */
2236                 int ok = 1;
2237                 for (i = 0 ; i < conf->raid_disks ; i++)
2238                         if (r1_bio->bios[i]->bi_end_io == end_sync_write) {
2239                                 mdk_rdev_t *rdev =
2240                                         rcu_dereference(conf->mirrors[i].rdev);
2241                                 ok = rdev_set_badblocks(rdev, sector_nr,
2242                                                         min_bad, 0
2243                                         ) && ok;
2244                         }
2245                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
2246                 *skipped = 1;
2247                 put_buf(r1_bio);
2248
2249                 if (!ok) {
2250                         /* Cannot record the badblocks, so need to
2251                          * abort the resync.
2252                          * If there are multiple read targets, could just
2253                          * fail the really bad ones ???
2254                          */
2255                         conf->recovery_disabled = mddev->recovery_disabled;
2256                         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2257                         return 0;
2258                 } else
2259                         return min_bad;
2260
2261         }
2262         if (min_bad > 0 && min_bad < good_sectors) {
2263                 /* only resync enough to reach the next bad->good
2264                  * transition */
2265                 good_sectors = min_bad;
2266         }
2267
2268         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
2269                 /* extra read targets are also write targets */
2270                 write_targets += read_targets-1;
2271
2272         if (write_targets == 0 || read_targets == 0) {
2273                 /* There is nowhere to write, so all non-sync
2274                  * drives must be failed - so we are finished
2275                  */
2276                 sector_t rv = max_sector - sector_nr;
2277                 *skipped = 1;
2278                 put_buf(r1_bio);
2279                 return rv;
2280         }
2281
2282         if (max_sector > mddev->resync_max)
2283                 max_sector = mddev->resync_max; /* Don't do IO beyond here */
2284         if (max_sector > sector_nr + good_sectors)
2285                 max_sector = sector_nr + good_sectors;
2286         nr_sectors = 0;
2287         sync_blocks = 0;
2288         do {
2289                 struct page *page;
2290                 int len = PAGE_SIZE;
2291                 if (sector_nr + (len>>9) > max_sector)
2292                         len = (max_sector - sector_nr) << 9;
2293                 if (len == 0)
2294                         break;
2295                 if (sync_blocks == 0) {
2296                         if (!bitmap_start_sync(mddev->bitmap, sector_nr,
2297                                                &sync_blocks, still_degraded) &&
2298                             !conf->fullsync &&
2299                             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2300                                 break;
2301                         BUG_ON(sync_blocks < (PAGE_SIZE>>9));
2302                         if ((len >> 9) > sync_blocks)
2303                                 len = sync_blocks<<9;
2304                 }
2305
2306                 for (i=0 ; i < conf->raid_disks; i++) {
2307                         bio = r1_bio->bios[i];
2308                         if (bio->bi_end_io) {
2309                                 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
2310                                 if (bio_add_page(bio, page, len, 0) == 0) {
2311                                         /* stop here */
2312                                         bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
2313                                         while (i > 0) {
2314                                                 i--;
2315                                                 bio = r1_bio->bios[i];
2316                                                 if (bio->bi_end_io==NULL)
2317                                                         continue;
2318                                                 /* remove last page from this bio */
2319                                                 bio->bi_vcnt--;
2320                                                 bio->bi_size -= len;
2321                                                 bio->bi_flags &= ~(1<< BIO_SEG_VALID);
2322                                         }
2323                                         goto bio_full;
2324                                 }
2325                         }
2326                 }
2327                 nr_sectors += len>>9;
2328                 sector_nr += len>>9;
2329                 sync_blocks -= (len>>9);
2330         } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
2331  bio_full:
2332         r1_bio->sectors = nr_sectors;
2333
2334         /* For a user-requested sync, we read all readable devices and do a
2335          * compare
2336          */
2337         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2338                 atomic_set(&r1_bio->remaining, read_targets);
2339                 for (i=0; i<conf->raid_disks; i++) {
2340                         bio = r1_bio->bios[i];
2341                         if (bio->bi_end_io == end_sync_read) {
2342                                 md_sync_acct(bio->bi_bdev, nr_sectors);
2343                                 generic_make_request(bio);
2344                         }
2345                 }
2346         } else {
2347                 atomic_set(&r1_bio->remaining, 1);
2348                 bio = r1_bio->bios[r1_bio->read_disk];
2349                 md_sync_acct(bio->bi_bdev, nr_sectors);
2350                 generic_make_request(bio);
2351
2352         }
2353         return nr_sectors;
2354 }
2355
2356 static sector_t raid1_size(mddev_t *mddev, sector_t sectors, int raid_disks)
2357 {
2358         if (sectors)
2359                 return sectors;
2360
2361         return mddev->dev_sectors;
2362 }
2363
2364 static conf_t *setup_conf(mddev_t *mddev)
2365 {
2366         conf_t *conf;
2367         int i;
2368         mirror_info_t *disk;
2369         mdk_rdev_t *rdev;
2370         int err = -ENOMEM;
2371
2372         conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
2373         if (!conf)
2374                 goto abort;
2375
2376         conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
2377                                  GFP_KERNEL);
2378         if (!conf->mirrors)
2379                 goto abort;
2380
2381         conf->tmppage = alloc_page(GFP_KERNEL);
2382         if (!conf->tmppage)
2383                 goto abort;
2384
2385         conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
2386         if (!conf->poolinfo)
2387                 goto abort;
2388         conf->poolinfo->raid_disks = mddev->raid_disks;
2389         conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2390                                           r1bio_pool_free,
2391                                           conf->poolinfo);
2392         if (!conf->r1bio_pool)
2393                 goto abort;
2394
2395         conf->poolinfo->mddev = mddev;
2396
2397         spin_lock_init(&conf->device_lock);
2398         list_for_each_entry(rdev, &mddev->disks, same_set) {
2399                 int disk_idx = rdev->raid_disk;
2400                 if (disk_idx >= mddev->raid_disks
2401                     || disk_idx < 0)
2402                         continue;
2403                 disk = conf->mirrors + disk_idx;
2404
2405                 disk->rdev = rdev;
2406
2407                 disk->head_position = 0;
2408         }
2409         conf->raid_disks = mddev->raid_disks;
2410         conf->mddev = mddev;
2411         INIT_LIST_HEAD(&conf->retry_list);
2412
2413         spin_lock_init(&conf->resync_lock);
2414         init_waitqueue_head(&conf->wait_barrier);
2415
2416         bio_list_init(&conf->pending_bio_list);
2417
2418         conf->last_used = -1;
2419         for (i = 0; i < conf->raid_disks; i++) {
2420
2421                 disk = conf->mirrors + i;
2422
2423                 if (!disk->rdev ||
2424                     !test_bit(In_sync, &disk->rdev->flags)) {
2425                         disk->head_position = 0;
2426                         if (disk->rdev)
2427                                 conf->fullsync = 1;
2428                 } else if (conf->last_used < 0)
2429                         /*
2430                          * The first working device is used as a
2431                          * starting point to read balancing.
2432                          */
2433                         conf->last_used = i;
2434         }
2435
2436         err = -EIO;
2437         if (conf->last_used < 0) {
2438                 printk(KERN_ERR "md/raid1:%s: no operational mirrors\n",
2439                        mdname(mddev));
2440                 goto abort;
2441         }
2442         err = -ENOMEM;
2443         conf->thread = md_register_thread(raid1d, mddev, NULL);
2444         if (!conf->thread) {
2445                 printk(KERN_ERR
2446                        "md/raid1:%s: couldn't allocate thread\n",
2447                        mdname(mddev));
2448                 goto abort;
2449         }
2450
2451         return conf;
2452
2453  abort:
2454         if (conf) {
2455                 if (conf->r1bio_pool)
2456                         mempool_destroy(conf->r1bio_pool);
2457                 kfree(conf->mirrors);
2458                 safe_put_page(conf->tmppage);
2459                 kfree(conf->poolinfo);
2460                 kfree(conf);
2461         }
2462         return ERR_PTR(err);
2463 }
2464
2465 static int run(mddev_t *mddev)
2466 {
2467         conf_t *conf;
2468         int i;
2469         mdk_rdev_t *rdev;
2470
2471         if (mddev->level != 1) {
2472                 printk(KERN_ERR "md/raid1:%s: raid level not set to mirroring (%d)\n",
2473                        mdname(mddev), mddev->level);
2474                 return -EIO;
2475         }
2476         if (mddev->reshape_position != MaxSector) {
2477                 printk(KERN_ERR "md/raid1:%s: reshape_position set but not supported\n",
2478                        mdname(mddev));
2479                 return -EIO;
2480         }
2481         /*
2482          * copy the already verified devices into our private RAID1
2483          * bookkeeping area. [whatever we allocate in run(),
2484          * should be freed in stop()]
2485          */
2486         if (mddev->private == NULL)
2487                 conf = setup_conf(mddev);
2488         else
2489                 conf = mddev->private;
2490
2491         if (IS_ERR(conf))
2492                 return PTR_ERR(conf);
2493
2494         list_for_each_entry(rdev, &mddev->disks, same_set) {
2495                 if (!mddev->gendisk)
2496                         continue;
2497                 disk_stack_limits(mddev->gendisk, rdev->bdev,
2498                                   rdev->data_offset << 9);
2499                 /* as we don't honour merge_bvec_fn, we must never risk
2500                  * violating it, so limit ->max_segments to 1 lying within
2501                  * a single page, as a one page request is never in violation.
2502                  */
2503                 if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
2504                         blk_queue_max_segments(mddev->queue, 1);
2505                         blk_queue_segment_boundary(mddev->queue,
2506                                                    PAGE_CACHE_SIZE - 1);
2507                 }
2508         }
2509
2510         mddev->degraded = 0;
2511         for (i=0; i < conf->raid_disks; i++)
2512                 if (conf->mirrors[i].rdev == NULL ||
2513                     !test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
2514                     test_bit(Faulty, &conf->mirrors[i].rdev->flags))
2515                         mddev->degraded++;
2516
2517         if (conf->raid_disks - mddev->degraded == 1)
2518                 mddev->recovery_cp = MaxSector;
2519
2520         if (mddev->recovery_cp != MaxSector)
2521                 printk(KERN_NOTICE "md/raid1:%s: not clean"
2522                        " -- starting background reconstruction\n",
2523                        mdname(mddev));
2524         printk(KERN_INFO
2525                 "md/raid1:%s: active with %d out of %d mirrors\n",
2526                 mdname(mddev), mddev->raid_disks - mddev->degraded,
2527                 mddev->raid_disks);
2528
2529         /*
2530          * Ok, everything is just fine now
2531          */
2532         mddev->thread = conf->thread;
2533         conf->thread = NULL;
2534         mddev->private = conf;
2535
2536         md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
2537
2538         if (mddev->queue) {
2539                 mddev->queue->backing_dev_info.congested_fn = raid1_congested;
2540                 mddev->queue->backing_dev_info.congested_data = mddev;
2541         }
2542         return md_integrity_register(mddev);
2543 }
2544
2545 static int stop(mddev_t *mddev)
2546 {
2547         conf_t *conf = mddev->private;
2548         struct bitmap *bitmap = mddev->bitmap;
2549
2550         /* wait for behind writes to complete */
2551         if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
2552                 printk(KERN_INFO "md/raid1:%s: behind writes in progress - waiting to stop.\n",
2553                        mdname(mddev));
2554                 /* need to kick something here to make sure I/O goes? */
2555                 wait_event(bitmap->behind_wait,
2556                            atomic_read(&bitmap->behind_writes) == 0);
2557         }
2558
2559         raise_barrier(conf);
2560         lower_barrier(conf);
2561
2562         md_unregister_thread(&mddev->thread);
2563         if (conf->r1bio_pool)
2564                 mempool_destroy(conf->r1bio_pool);
2565         kfree(conf->mirrors);
2566         kfree(conf->poolinfo);
2567         kfree(conf);
2568         mddev->private = NULL;
2569         return 0;
2570 }
2571
2572 static int raid1_resize(mddev_t *mddev, sector_t sectors)
2573 {
2574         /* no resync is happening, and there is enough space
2575          * on all devices, so we can resize.
2576          * We need to make sure resync covers any new space.
2577          * If the array is shrinking we should possibly wait until
2578          * any io in the removed space completes, but it hardly seems
2579          * worth it.
2580          */
2581         md_set_array_sectors(mddev, raid1_size(mddev, sectors, 0));
2582         if (mddev->array_sectors > raid1_size(mddev, sectors, 0))
2583                 return -EINVAL;
2584         set_capacity(mddev->gendisk, mddev->array_sectors);
2585         revalidate_disk(mddev->gendisk);
2586         if (sectors > mddev->dev_sectors &&
2587             mddev->recovery_cp > mddev->dev_sectors) {
2588                 mddev->recovery_cp = mddev->dev_sectors;
2589                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2590         }
2591         mddev->dev_sectors = sectors;
2592         mddev->resync_max_sectors = sectors;
2593         return 0;
2594 }
2595
2596 static int raid1_reshape(mddev_t *mddev)
2597 {
2598         /* We need to:
2599          * 1/ resize the r1bio_pool
2600          * 2/ resize conf->mirrors
2601          *
2602          * We allocate a new r1bio_pool if we can.
2603          * Then raise a device barrier and wait until all IO stops.
2604          * Then resize conf->mirrors and swap in the new r1bio pool.
2605          *
2606          * At the same time, we "pack" the devices so that all the missing
2607          * devices have the higher raid_disk numbers.
2608          */
2609         mempool_t *newpool, *oldpool;
2610         struct pool_info *newpoolinfo;
2611         mirror_info_t *newmirrors;
2612         conf_t *conf = mddev->private;
2613         int cnt, raid_disks;
2614         unsigned long flags;
2615         int d, d2, err;
2616
2617         /* Cannot change chunk_size, layout, or level */
2618         if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
2619             mddev->layout != mddev->new_layout ||
2620             mddev->level != mddev->new_level) {
2621                 mddev->new_chunk_sectors = mddev->chunk_sectors;
2622                 mddev->new_layout = mddev->layout;
2623                 mddev->new_level = mddev->level;
2624                 return -EINVAL;
2625         }
2626
2627         err = md_allow_write(mddev);
2628         if (err)
2629                 return err;
2630
2631         raid_disks = mddev->raid_disks + mddev->delta_disks;
2632
2633         if (raid_disks < conf->raid_disks) {
2634                 cnt=0;
2635                 for (d= 0; d < conf->raid_disks; d++)
2636                         if (conf->mirrors[d].rdev)
2637                                 cnt++;
2638                 if (cnt > raid_disks)
2639                         return -EBUSY;
2640         }
2641
2642         newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
2643         if (!newpoolinfo)
2644                 return -ENOMEM;
2645         newpoolinfo->mddev = mddev;
2646         newpoolinfo->raid_disks = raid_disks;
2647
2648         newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2649                                  r1bio_pool_free, newpoolinfo);
2650         if (!newpool) {
2651                 kfree(newpoolinfo);
2652                 return -ENOMEM;
2653         }
2654         newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
2655         if (!newmirrors) {
2656                 kfree(newpoolinfo);
2657                 mempool_destroy(newpool);
2658                 return -ENOMEM;
2659         }
2660
2661         raise_barrier(conf);
2662
2663         /* ok, everything is stopped */
2664         oldpool = conf->r1bio_pool;
2665         conf->r1bio_pool = newpool;
2666
2667         for (d = d2 = 0; d < conf->raid_disks; d++) {
2668                 mdk_rdev_t *rdev = conf->mirrors[d].rdev;
2669                 if (rdev && rdev->raid_disk != d2) {
2670                         sysfs_unlink_rdev(mddev, rdev);
2671                         rdev->raid_disk = d2;
2672                         sysfs_unlink_rdev(mddev, rdev);
2673                         if (sysfs_link_rdev(mddev, rdev))
2674                                 printk(KERN_WARNING
2675                                        "md/raid1:%s: cannot register rd%d\n",
2676                                        mdname(mddev), rdev->raid_disk);
2677                 }
2678                 if (rdev)
2679                         newmirrors[d2++].rdev = rdev;
2680         }
2681         kfree(conf->mirrors);
2682         conf->mirrors = newmirrors;
2683         kfree(conf->poolinfo);
2684         conf->poolinfo = newpoolinfo;
2685
2686         spin_lock_irqsave(&conf->device_lock, flags);
2687         mddev->degraded += (raid_disks - conf->raid_disks);
2688         spin_unlock_irqrestore(&conf->device_lock, flags);
2689         conf->raid_disks = mddev->raid_disks = raid_disks;
2690         mddev->delta_disks = 0;
2691
2692         conf->last_used = 0; /* just make sure it is in-range */
2693         lower_barrier(conf);
2694
2695         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2696         md_wakeup_thread(mddev->thread);
2697
2698         mempool_destroy(oldpool);
2699         return 0;
2700 }
2701
2702 static void raid1_quiesce(mddev_t *mddev, int state)
2703 {
2704         conf_t *conf = mddev->private;
2705
2706         switch(state) {
2707         case 2: /* wake for suspend */
2708                 wake_up(&conf->wait_barrier);
2709                 break;
2710         case 1:
2711                 raise_barrier(conf);
2712                 break;
2713         case 0:
2714                 lower_barrier(conf);
2715                 break;
2716         }
2717 }
2718
2719 static void *raid1_takeover(mddev_t *mddev)
2720 {
2721         /* raid1 can take over:
2722          *  raid5 with 2 devices, any layout or chunk size
2723          */
2724         if (mddev->level == 5 && mddev->raid_disks == 2) {
2725                 conf_t *conf;
2726                 mddev->new_level = 1;
2727                 mddev->new_layout = 0;
2728                 mddev->new_chunk_sectors = 0;
2729                 conf = setup_conf(mddev);
2730                 if (!IS_ERR(conf))
2731                         conf->barrier = 1;
2732                 return conf;
2733         }
2734         return ERR_PTR(-EINVAL);
2735 }
2736
2737 static struct mdk_personality raid1_personality =
2738 {
2739         .name           = "raid1",
2740         .level          = 1,
2741         .owner          = THIS_MODULE,
2742         .make_request   = make_request,
2743         .run            = run,
2744         .stop           = stop,
2745         .status         = status,
2746         .error_handler  = error,
2747         .hot_add_disk   = raid1_add_disk,
2748         .hot_remove_disk= raid1_remove_disk,
2749         .spare_active   = raid1_spare_active,
2750         .sync_request   = sync_request,
2751         .resize         = raid1_resize,
2752         .size           = raid1_size,
2753         .check_reshape  = raid1_reshape,
2754         .quiesce        = raid1_quiesce,
2755         .takeover       = raid1_takeover,
2756 };
2757
2758 static int __init raid_init(void)
2759 {
2760         return register_md_personality(&raid1_personality);
2761 }
2762
2763 static void raid_exit(void)
2764 {
2765         unregister_md_personality(&raid1_personality);
2766 }
2767
2768 module_init(raid_init);
2769 module_exit(raid_exit);
2770 MODULE_LICENSE("GPL");
2771 MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
2772 MODULE_ALIAS("md-personality-3"); /* RAID1 */
2773 MODULE_ALIAS("md-raid1");
2774 MODULE_ALIAS("md-level-1");