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 int 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 0;
 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 0;
 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         return 0;
1128 }
1129
1130 static void status(struct seq_file *seq, mddev_t *mddev)
1131 {
1132         conf_t *conf = mddev->private;
1133         int i;
1134
1135         seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1136                    conf->raid_disks - mddev->degraded);
1137         rcu_read_lock();
1138         for (i = 0; i < conf->raid_disks; i++) {
1139                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1140                 seq_printf(seq, "%s",
1141                            rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1142         }
1143         rcu_read_unlock();
1144         seq_printf(seq, "]");
1145 }
1146
1147
1148 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
1149 {
1150         char b[BDEVNAME_SIZE];
1151         conf_t *conf = mddev->private;
1152
1153         /*
1154          * If it is not operational, then we have already marked it as dead
1155          * else if it is the last working disks, ignore the error, let the
1156          * next level up know.
1157          * else mark the drive as failed
1158          */
1159         if (test_bit(In_sync, &rdev->flags)
1160             && (conf->raid_disks - mddev->degraded) == 1) {
1161                 /*
1162                  * Don't fail the drive, act as though we were just a
1163                  * normal single drive.
1164                  * However don't try a recovery from this drive as
1165                  * it is very likely to fail.
1166                  */
1167                 conf->recovery_disabled = mddev->recovery_disabled;
1168                 return;
1169         }
1170         set_bit(Blocked, &rdev->flags);
1171         if (test_and_clear_bit(In_sync, &rdev->flags)) {
1172                 unsigned long flags;
1173                 spin_lock_irqsave(&conf->device_lock, flags);
1174                 mddev->degraded++;
1175                 set_bit(Faulty, &rdev->flags);
1176                 spin_unlock_irqrestore(&conf->device_lock, flags);
1177                 /*
1178                  * if recovery is running, make sure it aborts.
1179                  */
1180                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1181         } else
1182                 set_bit(Faulty, &rdev->flags);
1183         set_bit(MD_CHANGE_DEVS, &mddev->flags);
1184         printk(KERN_ALERT
1185                "md/raid1:%s: Disk failure on %s, disabling device.\n"
1186                "md/raid1:%s: Operation continuing on %d devices.\n",
1187                mdname(mddev), bdevname(rdev->bdev, b),
1188                mdname(mddev), conf->raid_disks - mddev->degraded);
1189 }
1190
1191 static void print_conf(conf_t *conf)
1192 {
1193         int i;
1194
1195         printk(KERN_DEBUG "RAID1 conf printout:\n");
1196         if (!conf) {
1197                 printk(KERN_DEBUG "(!conf)\n");
1198                 return;
1199         }
1200         printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1201                 conf->raid_disks);
1202
1203         rcu_read_lock();
1204         for (i = 0; i < conf->raid_disks; i++) {
1205                 char b[BDEVNAME_SIZE];
1206                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1207                 if (rdev)
1208                         printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
1209                                i, !test_bit(In_sync, &rdev->flags),
1210                                !test_bit(Faulty, &rdev->flags),
1211                                bdevname(rdev->bdev,b));
1212         }
1213         rcu_read_unlock();
1214 }
1215
1216 static void close_sync(conf_t *conf)
1217 {
1218         wait_barrier(conf);
1219         allow_barrier(conf);
1220
1221         mempool_destroy(conf->r1buf_pool);
1222         conf->r1buf_pool = NULL;
1223 }
1224
1225 static int raid1_spare_active(mddev_t *mddev)
1226 {
1227         int i;
1228         conf_t *conf = mddev->private;
1229         int count = 0;
1230         unsigned long flags;
1231
1232         /*
1233          * Find all failed disks within the RAID1 configuration
1234          * and mark them readable.
1235          * Called under mddev lock, so rcu protection not needed.
1236          */
1237         for (i = 0; i < conf->raid_disks; i++) {
1238                 mdk_rdev_t *rdev = conf->mirrors[i].rdev;
1239                 if (rdev
1240                     && !test_bit(Faulty, &rdev->flags)
1241                     && !test_and_set_bit(In_sync, &rdev->flags)) {
1242                         count++;
1243                         sysfs_notify_dirent_safe(rdev->sysfs_state);
1244                 }
1245         }
1246         spin_lock_irqsave(&conf->device_lock, flags);
1247         mddev->degraded -= count;
1248         spin_unlock_irqrestore(&conf->device_lock, flags);
1249
1250         print_conf(conf);
1251         return count;
1252 }
1253
1254
1255 static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
1256 {
1257         conf_t *conf = mddev->private;
1258         int err = -EEXIST;
1259         int mirror = 0;
1260         mirror_info_t *p;
1261         int first = 0;
1262         int last = mddev->raid_disks - 1;
1263
1264         if (mddev->recovery_disabled == conf->recovery_disabled)
1265                 return -EBUSY;
1266
1267         if (rdev->raid_disk >= 0)
1268                 first = last = rdev->raid_disk;
1269
1270         for (mirror = first; mirror <= last; mirror++)
1271                 if ( !(p=conf->mirrors+mirror)->rdev) {
1272
1273                         disk_stack_limits(mddev->gendisk, rdev->bdev,
1274                                           rdev->data_offset << 9);
1275                         /* as we don't honour merge_bvec_fn, we must
1276                          * never risk violating it, so limit
1277                          * ->max_segments to one lying with a single
1278                          * page, as a one page request is never in
1279                          * violation.
1280                          */
1281                         if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
1282                                 blk_queue_max_segments(mddev->queue, 1);
1283                                 blk_queue_segment_boundary(mddev->queue,
1284                                                            PAGE_CACHE_SIZE - 1);
1285                         }
1286
1287                         p->head_position = 0;
1288                         rdev->raid_disk = mirror;
1289                         err = 0;
1290                         /* As all devices are equivalent, we don't need a full recovery
1291                          * if this was recently any drive of the array
1292                          */
1293                         if (rdev->saved_raid_disk < 0)
1294                                 conf->fullsync = 1;
1295                         rcu_assign_pointer(p->rdev, rdev);
1296                         break;
1297                 }
1298         md_integrity_add_rdev(rdev, mddev);
1299         print_conf(conf);
1300         return err;
1301 }
1302
1303 static int raid1_remove_disk(mddev_t *mddev, int number)
1304 {
1305         conf_t *conf = mddev->private;
1306         int err = 0;
1307         mdk_rdev_t *rdev;
1308         mirror_info_t *p = conf->mirrors+ number;
1309
1310         print_conf(conf);
1311         rdev = p->rdev;
1312         if (rdev) {
1313                 if (test_bit(In_sync, &rdev->flags) ||
1314                     atomic_read(&rdev->nr_pending)) {
1315                         err = -EBUSY;
1316                         goto abort;
1317                 }
1318                 /* Only remove non-faulty devices if recovery
1319                  * is not possible.
1320                  */
1321                 if (!test_bit(Faulty, &rdev->flags) &&
1322                     mddev->recovery_disabled != conf->recovery_disabled &&
1323                     mddev->degraded < conf->raid_disks) {
1324                         err = -EBUSY;
1325                         goto abort;
1326                 }
1327                 p->rdev = NULL;
1328                 synchronize_rcu();
1329                 if (atomic_read(&rdev->nr_pending)) {
1330                         /* lost the race, try later */
1331                         err = -EBUSY;
1332                         p->rdev = rdev;
1333                         goto abort;
1334                 }
1335                 err = md_integrity_register(mddev);
1336         }
1337 abort:
1338
1339         print_conf(conf);
1340         return err;
1341 }
1342
1343
1344 static void end_sync_read(struct bio *bio, int error)
1345 {
1346         r1bio_t *r1_bio = bio->bi_private;
1347         int i;
1348
1349         for (i=r1_bio->mddev->raid_disks; i--; )
1350                 if (r1_bio->bios[i] == bio)
1351                         break;
1352         BUG_ON(i < 0);
1353         update_head_pos(i, r1_bio);
1354         /*
1355          * we have read a block, now it needs to be re-written,
1356          * or re-read if the read failed.
1357          * We don't do much here, just schedule handling by raid1d
1358          */
1359         if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1360                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1361
1362         if (atomic_dec_and_test(&r1_bio->remaining))
1363                 reschedule_retry(r1_bio);
1364 }
1365
1366 static void end_sync_write(struct bio *bio, int error)
1367 {
1368         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1369         r1bio_t *r1_bio = bio->bi_private;
1370         mddev_t *mddev = r1_bio->mddev;
1371         conf_t *conf = mddev->private;
1372         int i;
1373         int mirror=0;
1374         sector_t first_bad;
1375         int bad_sectors;
1376
1377         for (i = 0; i < conf->raid_disks; i++)
1378                 if (r1_bio->bios[i] == bio) {
1379                         mirror = i;
1380                         break;
1381                 }
1382         if (!uptodate) {
1383                 sector_t sync_blocks = 0;
1384                 sector_t s = r1_bio->sector;
1385                 long sectors_to_go = r1_bio->sectors;
1386                 /* make sure these bits doesn't get cleared. */
1387                 do {
1388                         bitmap_end_sync(mddev->bitmap, s,
1389                                         &sync_blocks, 1);
1390                         s += sync_blocks;
1391                         sectors_to_go -= sync_blocks;
1392                 } while (sectors_to_go > 0);
1393                 set_bit(WriteErrorSeen,
1394                         &conf->mirrors[mirror].rdev->flags);
1395                 set_bit(R1BIO_WriteError, &r1_bio->state);
1396         } else if (is_badblock(conf->mirrors[mirror].rdev,
1397                                r1_bio->sector,
1398                                r1_bio->sectors,
1399                                &first_bad, &bad_sectors) &&
1400                    !is_badblock(conf->mirrors[r1_bio->read_disk].rdev,
1401                                 r1_bio->sector,
1402                                 r1_bio->sectors,
1403                                 &first_bad, &bad_sectors)
1404                 )
1405                 set_bit(R1BIO_MadeGood, &r1_bio->state);
1406
1407         update_head_pos(mirror, r1_bio);
1408
1409         if (atomic_dec_and_test(&r1_bio->remaining)) {
1410                 int s = r1_bio->sectors;
1411                 if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
1412                     test_bit(R1BIO_WriteError, &r1_bio->state))
1413                         reschedule_retry(r1_bio);
1414                 else {
1415                         put_buf(r1_bio);
1416                         md_done_sync(mddev, s, uptodate);
1417                 }
1418         }
1419 }
1420
1421 static int r1_sync_page_io(mdk_rdev_t *rdev, sector_t sector,
1422                             int sectors, struct page *page, int rw)
1423 {
1424         if (sync_page_io(rdev, sector, sectors << 9, page, rw, false))
1425                 /* success */
1426                 return 1;
1427         if (rw == WRITE)
1428                 set_bit(WriteErrorSeen, &rdev->flags);
1429         /* need to record an error - either for the block or the device */
1430         if (!rdev_set_badblocks(rdev, sector, sectors, 0))
1431                 md_error(rdev->mddev, rdev);
1432         return 0;
1433 }
1434
1435 static int fix_sync_read_error(r1bio_t *r1_bio)
1436 {
1437         /* Try some synchronous reads of other devices to get
1438          * good data, much like with normal read errors.  Only
1439          * read into the pages we already have so we don't
1440          * need to re-issue the read request.
1441          * We don't need to freeze the array, because being in an
1442          * active sync request, there is no normal IO, and
1443          * no overlapping syncs.
1444          * We don't need to check is_badblock() again as we
1445          * made sure that anything with a bad block in range
1446          * will have bi_end_io clear.
1447          */
1448         mddev_t *mddev = r1_bio->mddev;
1449         conf_t *conf = mddev->private;
1450         struct bio *bio = r1_bio->bios[r1_bio->read_disk];
1451         sector_t sect = r1_bio->sector;
1452         int sectors = r1_bio->sectors;
1453         int idx = 0;
1454
1455         while(sectors) {
1456                 int s = sectors;
1457                 int d = r1_bio->read_disk;
1458                 int success = 0;
1459                 mdk_rdev_t *rdev;
1460                 int start;
1461
1462                 if (s > (PAGE_SIZE>>9))
1463                         s = PAGE_SIZE >> 9;
1464                 do {
1465                         if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1466                                 /* No rcu protection needed here devices
1467                                  * can only be removed when no resync is
1468                                  * active, and resync is currently active
1469                                  */
1470                                 rdev = conf->mirrors[d].rdev;
1471                                 if (sync_page_io(rdev, sect, s<<9,
1472                                                  bio->bi_io_vec[idx].bv_page,
1473                                                  READ, false)) {
1474                                         success = 1;
1475                                         break;
1476                                 }
1477                         }
1478                         d++;
1479                         if (d == conf->raid_disks)
1480                                 d = 0;
1481                 } while (!success && d != r1_bio->read_disk);
1482
1483                 if (!success) {
1484                         char b[BDEVNAME_SIZE];
1485                         int abort = 0;
1486                         /* Cannot read from anywhere, this block is lost.
1487                          * Record a bad block on each device.  If that doesn't
1488                          * work just disable and interrupt the recovery.
1489                          * Don't fail devices as that won't really help.
1490                          */
1491                         printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O read error"
1492                                " for block %llu\n",
1493                                mdname(mddev),
1494                                bdevname(bio->bi_bdev, b),
1495                                (unsigned long long)r1_bio->sector);
1496                         for (d = 0; d < conf->raid_disks; d++) {
1497                                 rdev = conf->mirrors[d].rdev;
1498                                 if (!rdev || test_bit(Faulty, &rdev->flags))
1499                                         continue;
1500                                 if (!rdev_set_badblocks(rdev, sect, s, 0))
1501                                         abort = 1;
1502                         }
1503                         if (abort) {
1504                                 mddev->recovery_disabled = 1;
1505                                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1506                                 md_done_sync(mddev, r1_bio->sectors, 0);
1507                                 put_buf(r1_bio);
1508                                 return 0;
1509                         }
1510                         /* Try next page */
1511                         sectors -= s;
1512                         sect += s;
1513                         idx++;
1514                         continue;
1515                 }
1516
1517                 start = d;
1518                 /* write it back and re-read */
1519                 while (d != r1_bio->read_disk) {
1520                         if (d == 0)
1521                                 d = conf->raid_disks;
1522                         d--;
1523                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1524                                 continue;
1525                         rdev = conf->mirrors[d].rdev;
1526                         if (r1_sync_page_io(rdev, sect, s,
1527                                             bio->bi_io_vec[idx].bv_page,
1528                                             WRITE) == 0) {
1529                                 r1_bio->bios[d]->bi_end_io = NULL;
1530                                 rdev_dec_pending(rdev, mddev);
1531                         }
1532                 }
1533                 d = start;
1534                 while (d != r1_bio->read_disk) {
1535                         if (d == 0)
1536                                 d = conf->raid_disks;
1537                         d--;
1538                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1539                                 continue;
1540                         rdev = conf->mirrors[d].rdev;
1541                         if (r1_sync_page_io(rdev, sect, s,
1542                                             bio->bi_io_vec[idx].bv_page,
1543                                             READ) != 0)
1544                                 atomic_add(s, &rdev->corrected_errors);
1545                 }
1546                 sectors -= s;
1547                 sect += s;
1548                 idx ++;
1549         }
1550         set_bit(R1BIO_Uptodate, &r1_bio->state);
1551         set_bit(BIO_UPTODATE, &bio->bi_flags);
1552         return 1;
1553 }
1554
1555 static int process_checks(r1bio_t *r1_bio)
1556 {
1557         /* We have read all readable devices.  If we haven't
1558          * got the block, then there is no hope left.
1559          * If we have, then we want to do a comparison
1560          * and skip the write if everything is the same.
1561          * If any blocks failed to read, then we need to
1562          * attempt an over-write
1563          */
1564         mddev_t *mddev = r1_bio->mddev;
1565         conf_t *conf = mddev->private;
1566         int primary;
1567         int i;
1568
1569         for (primary = 0; primary < conf->raid_disks; primary++)
1570                 if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1571                     test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
1572                         r1_bio->bios[primary]->bi_end_io = NULL;
1573                         rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1574                         break;
1575                 }
1576         r1_bio->read_disk = primary;
1577         for (i = 0; i < conf->raid_disks; i++) {
1578                 int j;
1579                 int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
1580                 struct bio *pbio = r1_bio->bios[primary];
1581                 struct bio *sbio = r1_bio->bios[i];
1582                 int size;
1583
1584                 if (r1_bio->bios[i]->bi_end_io != end_sync_read)
1585                         continue;
1586
1587                 if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
1588                         for (j = vcnt; j-- ; ) {
1589                                 struct page *p, *s;
1590                                 p = pbio->bi_io_vec[j].bv_page;
1591                                 s = sbio->bi_io_vec[j].bv_page;
1592                                 if (memcmp(page_address(p),
1593                                            page_address(s),
1594                                            PAGE_SIZE))
1595                                         break;
1596                         }
1597                 } else
1598                         j = 0;
1599                 if (j >= 0)
1600                         mddev->resync_mismatches += r1_bio->sectors;
1601                 if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
1602                               && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
1603                         /* No need to write to this device. */
1604                         sbio->bi_end_io = NULL;
1605                         rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1606                         continue;
1607                 }
1608                 /* fixup the bio for reuse */
1609                 sbio->bi_vcnt = vcnt;
1610                 sbio->bi_size = r1_bio->sectors << 9;
1611                 sbio->bi_idx = 0;
1612                 sbio->bi_phys_segments = 0;
1613                 sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1614                 sbio->bi_flags |= 1 << BIO_UPTODATE;
1615                 sbio->bi_next = NULL;
1616                 sbio->bi_sector = r1_bio->sector +
1617                         conf->mirrors[i].rdev->data_offset;
1618                 sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1619                 size = sbio->bi_size;
1620                 for (j = 0; j < vcnt ; j++) {
1621                         struct bio_vec *bi;
1622                         bi = &sbio->bi_io_vec[j];
1623                         bi->bv_offset = 0;
1624                         if (size > PAGE_SIZE)
1625                                 bi->bv_len = PAGE_SIZE;
1626                         else
1627                                 bi->bv_len = size;
1628                         size -= PAGE_SIZE;
1629                         memcpy(page_address(bi->bv_page),
1630                                page_address(pbio->bi_io_vec[j].bv_page),
1631                                PAGE_SIZE);
1632                 }
1633         }
1634         return 0;
1635 }
1636
1637 static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
1638 {
1639         conf_t *conf = mddev->private;
1640         int i;
1641         int disks = conf->raid_disks;
1642         struct bio *bio, *wbio;
1643
1644         bio = r1_bio->bios[r1_bio->read_disk];
1645
1646         if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
1647                 /* ouch - failed to read all of that. */
1648                 if (!fix_sync_read_error(r1_bio))
1649                         return;
1650
1651         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1652                 if (process_checks(r1_bio) < 0)
1653                         return;
1654         /*
1655          * schedule writes
1656          */
1657         atomic_set(&r1_bio->remaining, 1);
1658         for (i = 0; i < disks ; i++) {
1659                 wbio = r1_bio->bios[i];
1660                 if (wbio->bi_end_io == NULL ||
1661                     (wbio->bi_end_io == end_sync_read &&
1662                      (i == r1_bio->read_disk ||
1663                       !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
1664                         continue;
1665
1666                 wbio->bi_rw = WRITE;
1667                 wbio->bi_end_io = end_sync_write;
1668                 atomic_inc(&r1_bio->remaining);
1669                 md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1670
1671                 generic_make_request(wbio);
1672         }
1673
1674         if (atomic_dec_and_test(&r1_bio->remaining)) {
1675                 /* if we're here, all write(s) have completed, so clean up */
1676                 md_done_sync(mddev, r1_bio->sectors, 1);
1677                 put_buf(r1_bio);
1678         }
1679 }
1680
1681 /*
1682  * This is a kernel thread which:
1683  *
1684  *      1.      Retries failed read operations on working mirrors.
1685  *      2.      Updates the raid superblock when problems encounter.
1686  *      3.      Performs writes following reads for array synchronising.
1687  */
1688
1689 static void fix_read_error(conf_t *conf, int read_disk,
1690                            sector_t sect, int sectors)
1691 {
1692         mddev_t *mddev = conf->mddev;
1693         while(sectors) {
1694                 int s = sectors;
1695                 int d = read_disk;
1696                 int success = 0;
1697                 int start;
1698                 mdk_rdev_t *rdev;
1699
1700                 if (s > (PAGE_SIZE>>9))
1701                         s = PAGE_SIZE >> 9;
1702
1703                 do {
1704                         /* Note: no rcu protection needed here
1705                          * as this is synchronous in the raid1d thread
1706                          * which is the thread that might remove
1707                          * a device.  If raid1d ever becomes multi-threaded....
1708                          */
1709                         sector_t first_bad;
1710                         int bad_sectors;
1711
1712                         rdev = conf->mirrors[d].rdev;
1713                         if (rdev &&
1714                             test_bit(In_sync, &rdev->flags) &&
1715                             is_badblock(rdev, sect, s,
1716                                         &first_bad, &bad_sectors) == 0 &&
1717                             sync_page_io(rdev, sect, s<<9,
1718                                          conf->tmppage, READ, false))
1719                                 success = 1;
1720                         else {
1721                                 d++;
1722                                 if (d == conf->raid_disks)
1723                                         d = 0;
1724                         }
1725                 } while (!success && d != read_disk);
1726
1727                 if (!success) {
1728                         /* Cannot read from anywhere - mark it bad */
1729                         mdk_rdev_t *rdev = conf->mirrors[read_disk].rdev;
1730                         if (!rdev_set_badblocks(rdev, sect, s, 0))
1731                                 md_error(mddev, rdev);
1732                         break;
1733                 }
1734                 /* write it back and re-read */
1735                 start = d;
1736                 while (d != read_disk) {
1737                         if (d==0)
1738                                 d = conf->raid_disks;
1739                         d--;
1740                         rdev = conf->mirrors[d].rdev;
1741                         if (rdev &&
1742                             test_bit(In_sync, &rdev->flags))
1743                                 r1_sync_page_io(rdev, sect, s,
1744                                                 conf->tmppage, WRITE);
1745                 }
1746                 d = start;
1747                 while (d != read_disk) {
1748                         char b[BDEVNAME_SIZE];
1749                         if (d==0)
1750                                 d = conf->raid_disks;
1751                         d--;
1752                         rdev = conf->mirrors[d].rdev;
1753                         if (rdev &&
1754                             test_bit(In_sync, &rdev->flags)) {
1755                                 if (r1_sync_page_io(rdev, sect, s,
1756                                                     conf->tmppage, READ)) {
1757                                         atomic_add(s, &rdev->corrected_errors);
1758                                         printk(KERN_INFO
1759                                                "md/raid1:%s: read error corrected "
1760                                                "(%d sectors at %llu on %s)\n",
1761                                                mdname(mddev), s,
1762                                                (unsigned long long)(sect +
1763                                                    rdev->data_offset),
1764                                                bdevname(rdev->bdev, b));
1765                                 }
1766                         }
1767                 }
1768                 sectors -= s;
1769                 sect += s;
1770         }
1771 }
1772
1773 static void bi_complete(struct bio *bio, int error)
1774 {
1775         complete((struct completion *)bio->bi_private);
1776 }
1777
1778 static int submit_bio_wait(int rw, struct bio *bio)
1779 {
1780         struct completion event;
1781         rw |= REQ_SYNC;
1782
1783         init_completion(&event);
1784         bio->bi_private = &event;
1785         bio->bi_end_io = bi_complete;
1786         submit_bio(rw, bio);
1787         wait_for_completion(&event);
1788
1789         return test_bit(BIO_UPTODATE, &bio->bi_flags);
1790 }
1791
1792 static int narrow_write_error(r1bio_t *r1_bio, int i)
1793 {
1794         mddev_t *mddev = r1_bio->mddev;
1795         conf_t *conf = mddev->private;
1796         mdk_rdev_t *rdev = conf->mirrors[i].rdev;
1797         int vcnt, idx;
1798         struct bio_vec *vec;
1799
1800         /* bio has the data to be written to device 'i' where
1801          * we just recently had a write error.
1802          * We repeatedly clone the bio and trim down to one block,
1803          * then try the write.  Where the write fails we record
1804          * a bad block.
1805          * It is conceivable that the bio doesn't exactly align with
1806          * blocks.  We must handle this somehow.
1807          *
1808          * We currently own a reference on the rdev.
1809          */
1810
1811         int block_sectors;
1812         sector_t sector;
1813         int sectors;
1814         int sect_to_write = r1_bio->sectors;
1815         int ok = 1;
1816
1817         if (rdev->badblocks.shift < 0)
1818                 return 0;
1819
1820         block_sectors = 1 << rdev->badblocks.shift;
1821         sector = r1_bio->sector;
1822         sectors = ((sector + block_sectors)
1823                    & ~(sector_t)(block_sectors - 1))
1824                 - sector;
1825
1826         if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
1827                 vcnt = r1_bio->behind_page_count;
1828                 vec = r1_bio->behind_bvecs;
1829                 idx = 0;
1830                 while (vec[idx].bv_page == NULL)
1831                         idx++;
1832         } else {
1833                 vcnt = r1_bio->master_bio->bi_vcnt;
1834                 vec = r1_bio->master_bio->bi_io_vec;
1835                 idx = r1_bio->master_bio->bi_idx;
1836         }
1837         while (sect_to_write) {
1838                 struct bio *wbio;
1839                 if (sectors > sect_to_write)
1840                         sectors = sect_to_write;
1841                 /* Write at 'sector' for 'sectors'*/
1842
1843                 wbio = bio_alloc_mddev(GFP_NOIO, vcnt, mddev);
1844                 memcpy(wbio->bi_io_vec, vec, vcnt * sizeof(struct bio_vec));
1845                 wbio->bi_sector = r1_bio->sector;
1846                 wbio->bi_rw = WRITE;
1847                 wbio->bi_vcnt = vcnt;
1848                 wbio->bi_size = r1_bio->sectors << 9;
1849                 wbio->bi_idx = idx;
1850
1851                 md_trim_bio(wbio, sector - r1_bio->sector, sectors);
1852                 wbio->bi_sector += rdev->data_offset;
1853                 wbio->bi_bdev = rdev->bdev;
1854                 if (submit_bio_wait(WRITE, wbio) == 0)
1855                         /* failure! */
1856                         ok = rdev_set_badblocks(rdev, sector,
1857                                                 sectors, 0)
1858                                 && ok;
1859
1860                 bio_put(wbio);
1861                 sect_to_write -= sectors;
1862                 sector += sectors;
1863                 sectors = block_sectors;
1864         }
1865         return ok;
1866 }
1867
1868 static void handle_sync_write_finished(conf_t *conf, r1bio_t *r1_bio)
1869 {
1870         int m;
1871         int s = r1_bio->sectors;
1872         for (m = 0; m < conf->raid_disks ; m++) {
1873                 mdk_rdev_t *rdev = conf->mirrors[m].rdev;
1874                 struct bio *bio = r1_bio->bios[m];
1875                 if (bio->bi_end_io == NULL)
1876                         continue;
1877                 if (test_bit(BIO_UPTODATE, &bio->bi_flags) &&
1878                     test_bit(R1BIO_MadeGood, &r1_bio->state)) {
1879                         rdev_clear_badblocks(rdev, r1_bio->sector, s);
1880                 }
1881                 if (!test_bit(BIO_UPTODATE, &bio->bi_flags) &&
1882                     test_bit(R1BIO_WriteError, &r1_bio->state)) {
1883                         if (!rdev_set_badblocks(rdev, r1_bio->sector, s, 0))
1884                                 md_error(conf->mddev, rdev);
1885                 }
1886         }
1887         put_buf(r1_bio);
1888         md_done_sync(conf->mddev, s, 1);
1889 }
1890
1891 static void handle_write_finished(conf_t *conf, r1bio_t *r1_bio)
1892 {
1893         int m;
1894         for (m = 0; m < conf->raid_disks ; m++)
1895                 if (r1_bio->bios[m] == IO_MADE_GOOD) {
1896                         mdk_rdev_t *rdev = conf->mirrors[m].rdev;
1897                         rdev_clear_badblocks(rdev,
1898                                              r1_bio->sector,
1899                                              r1_bio->sectors);
1900                         rdev_dec_pending(rdev, conf->mddev);
1901                 } else if (r1_bio->bios[m] != NULL) {
1902                         /* This drive got a write error.  We need to
1903                          * narrow down and record precise write
1904                          * errors.
1905                          */
1906                         if (!narrow_write_error(r1_bio, m)) {
1907                                 md_error(conf->mddev,
1908                                          conf->mirrors[m].rdev);
1909                                 /* an I/O failed, we can't clear the bitmap */
1910                                 set_bit(R1BIO_Degraded, &r1_bio->state);
1911                         }
1912                         rdev_dec_pending(conf->mirrors[m].rdev,
1913                                          conf->mddev);
1914                 }
1915         if (test_bit(R1BIO_WriteError, &r1_bio->state))
1916                 close_write(r1_bio);
1917         raid_end_bio_io(r1_bio);
1918 }
1919
1920 static void handle_read_error(conf_t *conf, r1bio_t *r1_bio)
1921 {
1922         int disk;
1923         int max_sectors;
1924         mddev_t *mddev = conf->mddev;
1925         struct bio *bio;
1926         char b[BDEVNAME_SIZE];
1927         mdk_rdev_t *rdev;
1928
1929         clear_bit(R1BIO_ReadError, &r1_bio->state);
1930         /* we got a read error. Maybe the drive is bad.  Maybe just
1931          * the block and we can fix it.
1932          * We freeze all other IO, and try reading the block from
1933          * other devices.  When we find one, we re-write
1934          * and check it that fixes the read error.
1935          * This is all done synchronously while the array is
1936          * frozen
1937          */
1938         if (mddev->ro == 0) {
1939                 freeze_array(conf);
1940                 fix_read_error(conf, r1_bio->read_disk,
1941                                r1_bio->sector, r1_bio->sectors);
1942                 unfreeze_array(conf);
1943         } else
1944                 md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
1945
1946         bio = r1_bio->bios[r1_bio->read_disk];
1947         bdevname(bio->bi_bdev, b);
1948 read_more:
1949         disk = read_balance(conf, r1_bio, &max_sectors);
1950         if (disk == -1) {
1951                 printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O"
1952                        " read error for block %llu\n",
1953                        mdname(mddev), b, (unsigned long long)r1_bio->sector);
1954                 raid_end_bio_io(r1_bio);
1955         } else {
1956                 const unsigned long do_sync
1957                         = r1_bio->master_bio->bi_rw & REQ_SYNC;
1958                 if (bio) {
1959                         r1_bio->bios[r1_bio->read_disk] =
1960                                 mddev->ro ? IO_BLOCKED : NULL;
1961                         bio_put(bio);
1962                 }
1963                 r1_bio->read_disk = disk;
1964                 bio = bio_clone_mddev(r1_bio->master_bio, GFP_NOIO, mddev);
1965                 md_trim_bio(bio, r1_bio->sector - bio->bi_sector, max_sectors);
1966                 r1_bio->bios[r1_bio->read_disk] = bio;
1967                 rdev = conf->mirrors[disk].rdev;
1968                 printk_ratelimited(KERN_ERR
1969                                    "md/raid1:%s: redirecting sector %llu"
1970                                    " to other mirror: %s\n",
1971                                    mdname(mddev),
1972                                    (unsigned long long)r1_bio->sector,
1973                                    bdevname(rdev->bdev, b));
1974                 bio->bi_sector = r1_bio->sector + rdev->data_offset;
1975                 bio->bi_bdev = rdev->bdev;
1976                 bio->bi_end_io = raid1_end_read_request;
1977                 bio->bi_rw = READ | do_sync;
1978                 bio->bi_private = r1_bio;
1979                 if (max_sectors < r1_bio->sectors) {
1980                         /* Drat - have to split this up more */
1981                         struct bio *mbio = r1_bio->master_bio;
1982                         int sectors_handled = (r1_bio->sector + max_sectors
1983                                                - mbio->bi_sector);
1984                         r1_bio->sectors = max_sectors;
1985                         spin_lock_irq(&conf->device_lock);
1986                         if (mbio->bi_phys_segments == 0)
1987                                 mbio->bi_phys_segments = 2;
1988                         else
1989                                 mbio->bi_phys_segments++;
1990                         spin_unlock_irq(&conf->device_lock);
1991                         generic_make_request(bio);
1992                         bio = NULL;
1993
1994                         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
1995
1996                         r1_bio->master_bio = mbio;
1997                         r1_bio->sectors = (mbio->bi_size >> 9)
1998                                           - sectors_handled;
1999                         r1_bio->state = 0;
2000                         set_bit(R1BIO_ReadError, &r1_bio->state);
2001                         r1_bio->mddev = mddev;
2002                         r1_bio->sector = mbio->bi_sector + sectors_handled;
2003
2004                         goto read_more;
2005                 } else
2006                         generic_make_request(bio);
2007         }
2008 }
2009
2010 static void raid1d(mddev_t *mddev)
2011 {
2012         r1bio_t *r1_bio;
2013         unsigned long flags;
2014         conf_t *conf = mddev->private;
2015         struct list_head *head = &conf->retry_list;
2016         struct blk_plug plug;
2017
2018         md_check_recovery(mddev);
2019
2020         blk_start_plug(&plug);
2021         for (;;) {
2022
2023                 if (atomic_read(&mddev->plug_cnt) == 0)
2024                         flush_pending_writes(conf);
2025
2026                 spin_lock_irqsave(&conf->device_lock, flags);
2027                 if (list_empty(head)) {
2028                         spin_unlock_irqrestore(&conf->device_lock, flags);
2029                         break;
2030                 }
2031                 r1_bio = list_entry(head->prev, r1bio_t, retry_list);
2032                 list_del(head->prev);
2033                 conf->nr_queued--;
2034                 spin_unlock_irqrestore(&conf->device_lock, flags);
2035
2036                 mddev = r1_bio->mddev;
2037                 conf = mddev->private;
2038                 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
2039                         if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2040                             test_bit(R1BIO_WriteError, &r1_bio->state))
2041                                 handle_sync_write_finished(conf, r1_bio);
2042                         else
2043                                 sync_request_write(mddev, r1_bio);
2044                 } else if (test_bit(R1BIO_MadeGood, &r1_bio->state) ||
2045                            test_bit(R1BIO_WriteError, &r1_bio->state))
2046                         handle_write_finished(conf, r1_bio);
2047                 else if (test_bit(R1BIO_ReadError, &r1_bio->state))
2048                         handle_read_error(conf, r1_bio);
2049                 else
2050                         /* just a partial read to be scheduled from separate
2051                          * context
2052                          */
2053                         generic_make_request(r1_bio->bios[r1_bio->read_disk]);
2054
2055                 cond_resched();
2056                 if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
2057                         md_check_recovery(mddev);
2058         }
2059         blk_finish_plug(&plug);
2060 }
2061
2062
2063 static int init_resync(conf_t *conf)
2064 {
2065         int buffs;
2066
2067         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
2068         BUG_ON(conf->r1buf_pool);
2069         conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
2070                                           conf->poolinfo);
2071         if (!conf->r1buf_pool)
2072                 return -ENOMEM;
2073         conf->next_resync = 0;
2074         return 0;
2075 }
2076
2077 /*
2078  * perform a "sync" on one "block"
2079  *
2080  * We need to make sure that no normal I/O request - particularly write
2081  * requests - conflict with active sync requests.
2082  *
2083  * This is achieved by tracking pending requests and a 'barrier' concept
2084  * that can be installed to exclude normal IO requests.
2085  */
2086
2087 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
2088 {
2089         conf_t *conf = mddev->private;
2090         r1bio_t *r1_bio;
2091         struct bio *bio;
2092         sector_t max_sector, nr_sectors;
2093         int disk = -1;
2094         int i;
2095         int wonly = -1;
2096         int write_targets = 0, read_targets = 0;
2097         sector_t sync_blocks;
2098         int still_degraded = 0;
2099         int good_sectors = RESYNC_SECTORS;
2100         int min_bad = 0; /* number of sectors that are bad in all devices */
2101
2102         if (!conf->r1buf_pool)
2103                 if (init_resync(conf))
2104                         return 0;
2105
2106         max_sector = mddev->dev_sectors;
2107         if (sector_nr >= max_sector) {
2108                 /* If we aborted, we need to abort the
2109                  * sync on the 'current' bitmap chunk (there will
2110                  * only be one in raid1 resync.
2111                  * We can find the current addess in mddev->curr_resync
2112                  */
2113                 if (mddev->curr_resync < max_sector) /* aborted */
2114                         bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
2115                                                 &sync_blocks, 1);
2116                 else /* completed sync */
2117                         conf->fullsync = 0;
2118
2119                 bitmap_close_sync(mddev->bitmap);
2120                 close_sync(conf);
2121                 return 0;
2122         }
2123
2124         if (mddev->bitmap == NULL &&
2125             mddev->recovery_cp == MaxSector &&
2126             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
2127             conf->fullsync == 0) {
2128                 *skipped = 1;
2129                 return max_sector - sector_nr;
2130         }
2131         /* before building a request, check if we can skip these blocks..
2132          * This call the bitmap_start_sync doesn't actually record anything
2133          */
2134         if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
2135             !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2136                 /* We can skip this block, and probably several more */
2137                 *skipped = 1;
2138                 return sync_blocks;
2139         }
2140         /*
2141          * If there is non-resync activity waiting for a turn,
2142          * and resync is going fast enough,
2143          * then let it though before starting on this new sync request.
2144          */
2145         if (!go_faster && conf->nr_waiting)
2146                 msleep_interruptible(1000);
2147
2148         bitmap_cond_end_sync(mddev->bitmap, sector_nr);
2149         r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
2150         raise_barrier(conf);
2151
2152         conf->next_resync = sector_nr;
2153
2154         rcu_read_lock();
2155         /*
2156          * If we get a correctably read error during resync or recovery,
2157          * we might want to read from a different device.  So we
2158          * flag all drives that could conceivably be read from for READ,
2159          * and any others (which will be non-In_sync devices) for WRITE.
2160          * If a read fails, we try reading from something else for which READ
2161          * is OK.
2162          */
2163
2164         r1_bio->mddev = mddev;
2165         r1_bio->sector = sector_nr;
2166         r1_bio->state = 0;
2167         set_bit(R1BIO_IsSync, &r1_bio->state);
2168
2169         for (i=0; i < conf->raid_disks; i++) {
2170                 mdk_rdev_t *rdev;
2171                 bio = r1_bio->bios[i];
2172
2173                 /* take from bio_init */
2174                 bio->bi_next = NULL;
2175                 bio->bi_flags &= ~(BIO_POOL_MASK-1);
2176                 bio->bi_flags |= 1 << BIO_UPTODATE;
2177                 bio->bi_comp_cpu = -1;
2178                 bio->bi_rw = READ;
2179                 bio->bi_vcnt = 0;
2180                 bio->bi_idx = 0;
2181                 bio->bi_phys_segments = 0;
2182                 bio->bi_size = 0;
2183                 bio->bi_end_io = NULL;
2184                 bio->bi_private = NULL;
2185
2186                 rdev = rcu_dereference(conf->mirrors[i].rdev);
2187                 if (rdev == NULL ||
2188                     test_bit(Faulty, &rdev->flags)) {
2189                         still_degraded = 1;
2190                 } else if (!test_bit(In_sync, &rdev->flags)) {
2191                         bio->bi_rw = WRITE;
2192                         bio->bi_end_io = end_sync_write;
2193                         write_targets ++;
2194                 } else {
2195                         /* may need to read from here */
2196                         sector_t first_bad = MaxSector;
2197                         int bad_sectors;
2198
2199                         if (is_badblock(rdev, sector_nr, good_sectors,
2200                                         &first_bad, &bad_sectors)) {
2201                                 if (first_bad > sector_nr)
2202                                         good_sectors = first_bad - sector_nr;
2203                                 else {
2204                                         bad_sectors -= (sector_nr - first_bad);
2205                                         if (min_bad == 0 ||
2206                                             min_bad > bad_sectors)
2207                                                 min_bad = bad_sectors;
2208                                 }
2209                         }
2210                         if (sector_nr < first_bad) {
2211                                 if (test_bit(WriteMostly, &rdev->flags)) {
2212                                         if (wonly < 0)
2213                                                 wonly = i;
2214                                 } else {
2215                                         if (disk < 0)
2216                                                 disk = i;
2217                                 }
2218                                 bio->bi_rw = READ;
2219                                 bio->bi_end_io = end_sync_read;
2220                                 read_targets++;
2221                         }
2222                 }
2223                 if (bio->bi_end_io) {
2224                         atomic_inc(&rdev->nr_pending);
2225                         bio->bi_sector = sector_nr + rdev->data_offset;
2226                         bio->bi_bdev = rdev->bdev;
2227                         bio->bi_private = r1_bio;
2228                 }
2229         }
2230         rcu_read_unlock();
2231         if (disk < 0)
2232                 disk = wonly;
2233         r1_bio->read_disk = disk;
2234
2235         if (read_targets == 0 && min_bad > 0) {
2236                 /* These sectors are bad on all InSync devices, so we
2237                  * need to mark them bad on all write targets
2238                  */
2239                 int ok = 1;
2240                 for (i = 0 ; i < conf->raid_disks ; i++)
2241                         if (r1_bio->bios[i]->bi_end_io == end_sync_write) {
2242                                 mdk_rdev_t *rdev =
2243                                         rcu_dereference(conf->mirrors[i].rdev);
2244                                 ok = rdev_set_badblocks(rdev, sector_nr,
2245                                                         min_bad, 0
2246                                         ) && ok;
2247                         }
2248                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
2249                 *skipped = 1;
2250                 put_buf(r1_bio);
2251
2252                 if (!ok) {
2253                         /* Cannot record the badblocks, so need to
2254                          * abort the resync.
2255                          * If there are multiple read targets, could just
2256                          * fail the really bad ones ???
2257                          */
2258                         conf->recovery_disabled = mddev->recovery_disabled;
2259                         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2260                         return 0;
2261                 } else
2262                         return min_bad;
2263
2264         }
2265         if (min_bad > 0 && min_bad < good_sectors) {
2266                 /* only resync enough to reach the next bad->good
2267                  * transition */
2268                 good_sectors = min_bad;
2269         }
2270
2271         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
2272                 /* extra read targets are also write targets */
2273                 write_targets += read_targets-1;
2274
2275         if (write_targets == 0 || read_targets == 0) {
2276                 /* There is nowhere to write, so all non-sync
2277                  * drives must be failed - so we are finished
2278                  */
2279                 sector_t rv = max_sector - sector_nr;
2280                 *skipped = 1;
2281                 put_buf(r1_bio);
2282                 return rv;
2283         }
2284
2285         if (max_sector > mddev->resync_max)
2286                 max_sector = mddev->resync_max; /* Don't do IO beyond here */
2287         if (max_sector > sector_nr + good_sectors)
2288                 max_sector = sector_nr + good_sectors;
2289         nr_sectors = 0;
2290         sync_blocks = 0;
2291         do {
2292                 struct page *page;
2293                 int len = PAGE_SIZE;
2294                 if (sector_nr + (len>>9) > max_sector)
2295                         len = (max_sector - sector_nr) << 9;
2296                 if (len == 0)
2297                         break;
2298                 if (sync_blocks == 0) {
2299                         if (!bitmap_start_sync(mddev->bitmap, sector_nr,
2300                                                &sync_blocks, still_degraded) &&
2301                             !conf->fullsync &&
2302                             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2303                                 break;
2304                         BUG_ON(sync_blocks < (PAGE_SIZE>>9));
2305                         if ((len >> 9) > sync_blocks)
2306                                 len = sync_blocks<<9;
2307                 }
2308
2309                 for (i=0 ; i < conf->raid_disks; i++) {
2310                         bio = r1_bio->bios[i];
2311                         if (bio->bi_end_io) {
2312                                 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
2313                                 if (bio_add_page(bio, page, len, 0) == 0) {
2314                                         /* stop here */
2315                                         bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
2316                                         while (i > 0) {
2317                                                 i--;
2318                                                 bio = r1_bio->bios[i];
2319                                                 if (bio->bi_end_io==NULL)
2320                                                         continue;
2321                                                 /* remove last page from this bio */
2322                                                 bio->bi_vcnt--;
2323                                                 bio->bi_size -= len;
2324                                                 bio->bi_flags &= ~(1<< BIO_SEG_VALID);
2325                                         }
2326                                         goto bio_full;
2327                                 }
2328                         }
2329                 }
2330                 nr_sectors += len>>9;
2331                 sector_nr += len>>9;
2332                 sync_blocks -= (len>>9);
2333         } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
2334  bio_full:
2335         r1_bio->sectors = nr_sectors;
2336
2337         /* For a user-requested sync, we read all readable devices and do a
2338          * compare
2339          */
2340         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2341                 atomic_set(&r1_bio->remaining, read_targets);
2342                 for (i=0; i<conf->raid_disks; i++) {
2343                         bio = r1_bio->bios[i];
2344                         if (bio->bi_end_io == end_sync_read) {
2345                                 md_sync_acct(bio->bi_bdev, nr_sectors);
2346                                 generic_make_request(bio);
2347                         }
2348                 }
2349         } else {
2350                 atomic_set(&r1_bio->remaining, 1);
2351                 bio = r1_bio->bios[r1_bio->read_disk];
2352                 md_sync_acct(bio->bi_bdev, nr_sectors);
2353                 generic_make_request(bio);
2354
2355         }
2356         return nr_sectors;
2357 }
2358
2359 static sector_t raid1_size(mddev_t *mddev, sector_t sectors, int raid_disks)
2360 {
2361         if (sectors)
2362                 return sectors;
2363
2364         return mddev->dev_sectors;
2365 }
2366
2367 static conf_t *setup_conf(mddev_t *mddev)
2368 {
2369         conf_t *conf;
2370         int i;
2371         mirror_info_t *disk;
2372         mdk_rdev_t *rdev;
2373         int err = -ENOMEM;
2374
2375         conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
2376         if (!conf)
2377                 goto abort;
2378
2379         conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
2380                                  GFP_KERNEL);
2381         if (!conf->mirrors)
2382                 goto abort;
2383
2384         conf->tmppage = alloc_page(GFP_KERNEL);
2385         if (!conf->tmppage)
2386                 goto abort;
2387
2388         conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
2389         if (!conf->poolinfo)
2390                 goto abort;
2391         conf->poolinfo->raid_disks = mddev->raid_disks;
2392         conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2393                                           r1bio_pool_free,
2394                                           conf->poolinfo);
2395         if (!conf->r1bio_pool)
2396                 goto abort;
2397
2398         conf->poolinfo->mddev = mddev;
2399
2400         spin_lock_init(&conf->device_lock);
2401         list_for_each_entry(rdev, &mddev->disks, same_set) {
2402                 int disk_idx = rdev->raid_disk;
2403                 if (disk_idx >= mddev->raid_disks
2404                     || disk_idx < 0)
2405                         continue;
2406                 disk = conf->mirrors + disk_idx;
2407
2408                 disk->rdev = rdev;
2409
2410                 disk->head_position = 0;
2411         }
2412         conf->raid_disks = mddev->raid_disks;
2413         conf->mddev = mddev;
2414         INIT_LIST_HEAD(&conf->retry_list);
2415
2416         spin_lock_init(&conf->resync_lock);
2417         init_waitqueue_head(&conf->wait_barrier);
2418
2419         bio_list_init(&conf->pending_bio_list);
2420
2421         conf->last_used = -1;
2422         for (i = 0; i < conf->raid_disks; i++) {
2423
2424                 disk = conf->mirrors + i;
2425
2426                 if (!disk->rdev ||
2427                     !test_bit(In_sync, &disk->rdev->flags)) {
2428                         disk->head_position = 0;
2429                         if (disk->rdev)
2430                                 conf->fullsync = 1;
2431                 } else if (conf->last_used < 0)
2432                         /*
2433                          * The first working device is used as a
2434                          * starting point to read balancing.
2435                          */
2436                         conf->last_used = i;
2437         }
2438
2439         err = -EIO;
2440         if (conf->last_used < 0) {
2441                 printk(KERN_ERR "md/raid1:%s: no operational mirrors\n",
2442                        mdname(mddev));
2443                 goto abort;
2444         }
2445         err = -ENOMEM;
2446         conf->thread = md_register_thread(raid1d, mddev, NULL);
2447         if (!conf->thread) {
2448                 printk(KERN_ERR
2449                        "md/raid1:%s: couldn't allocate thread\n",
2450                        mdname(mddev));
2451                 goto abort;
2452         }
2453
2454         return conf;
2455
2456  abort:
2457         if (conf) {
2458                 if (conf->r1bio_pool)
2459                         mempool_destroy(conf->r1bio_pool);
2460                 kfree(conf->mirrors);
2461                 safe_put_page(conf->tmppage);
2462                 kfree(conf->poolinfo);
2463                 kfree(conf);
2464         }
2465         return ERR_PTR(err);
2466 }
2467
2468 static int run(mddev_t *mddev)
2469 {
2470         conf_t *conf;
2471         int i;
2472         mdk_rdev_t *rdev;
2473
2474         if (mddev->level != 1) {
2475                 printk(KERN_ERR "md/raid1:%s: raid level not set to mirroring (%d)\n",
2476                        mdname(mddev), mddev->level);
2477                 return -EIO;
2478         }
2479         if (mddev->reshape_position != MaxSector) {
2480                 printk(KERN_ERR "md/raid1:%s: reshape_position set but not supported\n",
2481                        mdname(mddev));
2482                 return -EIO;
2483         }
2484         /*
2485          * copy the already verified devices into our private RAID1
2486          * bookkeeping area. [whatever we allocate in run(),
2487          * should be freed in stop()]
2488          */
2489         if (mddev->private == NULL)
2490                 conf = setup_conf(mddev);
2491         else
2492                 conf = mddev->private;
2493
2494         if (IS_ERR(conf))
2495                 return PTR_ERR(conf);
2496
2497         list_for_each_entry(rdev, &mddev->disks, same_set) {
2498                 if (!mddev->gendisk)
2499                         continue;
2500                 disk_stack_limits(mddev->gendisk, rdev->bdev,
2501                                   rdev->data_offset << 9);
2502                 /* as we don't honour merge_bvec_fn, we must never risk
2503                  * violating it, so limit ->max_segments to 1 lying within
2504                  * a single page, as a one page request is never in violation.
2505                  */
2506                 if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
2507                         blk_queue_max_segments(mddev->queue, 1);
2508                         blk_queue_segment_boundary(mddev->queue,
2509                                                    PAGE_CACHE_SIZE - 1);
2510                 }
2511         }
2512
2513         mddev->degraded = 0;
2514         for (i=0; i < conf->raid_disks; i++)
2515                 if (conf->mirrors[i].rdev == NULL ||
2516                     !test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
2517                     test_bit(Faulty, &conf->mirrors[i].rdev->flags))
2518                         mddev->degraded++;
2519
2520         if (conf->raid_disks - mddev->degraded == 1)
2521                 mddev->recovery_cp = MaxSector;
2522
2523         if (mddev->recovery_cp != MaxSector)
2524                 printk(KERN_NOTICE "md/raid1:%s: not clean"
2525                        " -- starting background reconstruction\n",
2526                        mdname(mddev));
2527         printk(KERN_INFO
2528                 "md/raid1:%s: active with %d out of %d mirrors\n",
2529                 mdname(mddev), mddev->raid_disks - mddev->degraded,
2530                 mddev->raid_disks);
2531
2532         /*
2533          * Ok, everything is just fine now
2534          */
2535         mddev->thread = conf->thread;
2536         conf->thread = NULL;
2537         mddev->private = conf;
2538
2539         md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
2540
2541         if (mddev->queue) {
2542                 mddev->queue->backing_dev_info.congested_fn = raid1_congested;
2543                 mddev->queue->backing_dev_info.congested_data = mddev;
2544         }
2545         return md_integrity_register(mddev);
2546 }
2547
2548 static int stop(mddev_t *mddev)
2549 {
2550         conf_t *conf = mddev->private;
2551         struct bitmap *bitmap = mddev->bitmap;
2552
2553         /* wait for behind writes to complete */
2554         if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
2555                 printk(KERN_INFO "md/raid1:%s: behind writes in progress - waiting to stop.\n",
2556                        mdname(mddev));
2557                 /* need to kick something here to make sure I/O goes? */
2558                 wait_event(bitmap->behind_wait,
2559                            atomic_read(&bitmap->behind_writes) == 0);
2560         }
2561
2562         raise_barrier(conf);
2563         lower_barrier(conf);
2564
2565         md_unregister_thread(mddev->thread);
2566         mddev->thread = NULL;
2567         if (conf->r1bio_pool)
2568                 mempool_destroy(conf->r1bio_pool);
2569         kfree(conf->mirrors);
2570         kfree(conf->poolinfo);
2571         kfree(conf);
2572         mddev->private = NULL;
2573         return 0;
2574 }
2575
2576 static int raid1_resize(mddev_t *mddev, sector_t sectors)
2577 {
2578         /* no resync is happening, and there is enough space
2579          * on all devices, so we can resize.
2580          * We need to make sure resync covers any new space.
2581          * If the array is shrinking we should possibly wait until
2582          * any io in the removed space completes, but it hardly seems
2583          * worth it.
2584          */
2585         md_set_array_sectors(mddev, raid1_size(mddev, sectors, 0));
2586         if (mddev->array_sectors > raid1_size(mddev, sectors, 0))
2587                 return -EINVAL;
2588         set_capacity(mddev->gendisk, mddev->array_sectors);
2589         revalidate_disk(mddev->gendisk);
2590         if (sectors > mddev->dev_sectors &&
2591             mddev->recovery_cp > mddev->dev_sectors) {
2592                 mddev->recovery_cp = mddev->dev_sectors;
2593                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2594         }
2595         mddev->dev_sectors = sectors;
2596         mddev->resync_max_sectors = sectors;
2597         return 0;
2598 }
2599
2600 static int raid1_reshape(mddev_t *mddev)
2601 {
2602         /* We need to:
2603          * 1/ resize the r1bio_pool
2604          * 2/ resize conf->mirrors
2605          *
2606          * We allocate a new r1bio_pool if we can.
2607          * Then raise a device barrier and wait until all IO stops.
2608          * Then resize conf->mirrors and swap in the new r1bio pool.
2609          *
2610          * At the same time, we "pack" the devices so that all the missing
2611          * devices have the higher raid_disk numbers.
2612          */
2613         mempool_t *newpool, *oldpool;
2614         struct pool_info *newpoolinfo;
2615         mirror_info_t *newmirrors;
2616         conf_t *conf = mddev->private;
2617         int cnt, raid_disks;
2618         unsigned long flags;
2619         int d, d2, err;
2620
2621         /* Cannot change chunk_size, layout, or level */
2622         if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
2623             mddev->layout != mddev->new_layout ||
2624             mddev->level != mddev->new_level) {
2625                 mddev->new_chunk_sectors = mddev->chunk_sectors;
2626                 mddev->new_layout = mddev->layout;
2627                 mddev->new_level = mddev->level;
2628                 return -EINVAL;
2629         }
2630
2631         err = md_allow_write(mddev);
2632         if (err)
2633                 return err;
2634
2635         raid_disks = mddev->raid_disks + mddev->delta_disks;
2636
2637         if (raid_disks < conf->raid_disks) {
2638                 cnt=0;
2639                 for (d= 0; d < conf->raid_disks; d++)
2640                         if (conf->mirrors[d].rdev)
2641                                 cnt++;
2642                 if (cnt > raid_disks)
2643                         return -EBUSY;
2644         }
2645
2646         newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
2647         if (!newpoolinfo)
2648                 return -ENOMEM;
2649         newpoolinfo->mddev = mddev;
2650         newpoolinfo->raid_disks = raid_disks;
2651
2652         newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2653                                  r1bio_pool_free, newpoolinfo);
2654         if (!newpool) {
2655                 kfree(newpoolinfo);
2656                 return -ENOMEM;
2657         }
2658         newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
2659         if (!newmirrors) {
2660                 kfree(newpoolinfo);
2661                 mempool_destroy(newpool);
2662                 return -ENOMEM;
2663         }
2664
2665         raise_barrier(conf);
2666
2667         /* ok, everything is stopped */
2668         oldpool = conf->r1bio_pool;
2669         conf->r1bio_pool = newpool;
2670
2671         for (d = d2 = 0; d < conf->raid_disks; d++) {
2672                 mdk_rdev_t *rdev = conf->mirrors[d].rdev;
2673                 if (rdev && rdev->raid_disk != d2) {
2674                         sysfs_unlink_rdev(mddev, rdev);
2675                         rdev->raid_disk = d2;
2676                         sysfs_unlink_rdev(mddev, rdev);
2677                         if (sysfs_link_rdev(mddev, rdev))
2678                                 printk(KERN_WARNING
2679                                        "md/raid1:%s: cannot register rd%d\n",
2680                                        mdname(mddev), rdev->raid_disk);
2681                 }
2682                 if (rdev)
2683                         newmirrors[d2++].rdev = rdev;
2684         }
2685         kfree(conf->mirrors);
2686         conf->mirrors = newmirrors;
2687         kfree(conf->poolinfo);
2688         conf->poolinfo = newpoolinfo;
2689
2690         spin_lock_irqsave(&conf->device_lock, flags);
2691         mddev->degraded += (raid_disks - conf->raid_disks);
2692         spin_unlock_irqrestore(&conf->device_lock, flags);
2693         conf->raid_disks = mddev->raid_disks = raid_disks;
2694         mddev->delta_disks = 0;
2695
2696         conf->last_used = 0; /* just make sure it is in-range */
2697         lower_barrier(conf);
2698
2699         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2700         md_wakeup_thread(mddev->thread);
2701
2702         mempool_destroy(oldpool);
2703         return 0;
2704 }
2705
2706 static void raid1_quiesce(mddev_t *mddev, int state)
2707 {
2708         conf_t *conf = mddev->private;
2709
2710         switch(state) {
2711         case 2: /* wake for suspend */
2712                 wake_up(&conf->wait_barrier);
2713                 break;
2714         case 1:
2715                 raise_barrier(conf);
2716                 break;
2717         case 0:
2718                 lower_barrier(conf);
2719                 break;
2720         }
2721 }
2722
2723 static void *raid1_takeover(mddev_t *mddev)
2724 {
2725         /* raid1 can take over:
2726          *  raid5 with 2 devices, any layout or chunk size
2727          */
2728         if (mddev->level == 5 && mddev->raid_disks == 2) {
2729                 conf_t *conf;
2730                 mddev->new_level = 1;
2731                 mddev->new_layout = 0;
2732                 mddev->new_chunk_sectors = 0;
2733                 conf = setup_conf(mddev);
2734                 if (!IS_ERR(conf))
2735                         conf->barrier = 1;
2736                 return conf;
2737         }
2738         return ERR_PTR(-EINVAL);
2739 }
2740
2741 static struct mdk_personality raid1_personality =
2742 {
2743         .name           = "raid1",
2744         .level          = 1,
2745         .owner          = THIS_MODULE,
2746         .make_request   = make_request,
2747         .run            = run,
2748         .stop           = stop,
2749         .status         = status,
2750         .error_handler  = error,
2751         .hot_add_disk   = raid1_add_disk,
2752         .hot_remove_disk= raid1_remove_disk,
2753         .spare_active   = raid1_spare_active,
2754         .sync_request   = sync_request,
2755         .resize         = raid1_resize,
2756         .size           = raid1_size,
2757         .check_reshape  = raid1_reshape,
2758         .quiesce        = raid1_quiesce,
2759         .takeover       = raid1_takeover,
2760 };
2761
2762 static int __init raid_init(void)
2763 {
2764         return register_md_personality(&raid1_personality);
2765 }
2766
2767 static void raid_exit(void)
2768 {
2769         unregister_md_personality(&raid1_personality);
2770 }
2771
2772 module_init(raid_init);
2773 module_exit(raid_exit);
2774 MODULE_LICENSE("GPL");
2775 MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
2776 MODULE_ALIAS("md-personality-3"); /* RAID1 */
2777 MODULE_ALIAS("md-raid1");
2778 MODULE_ALIAS("md-level-1");