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 "dm-bio-list.h"
  35 #include <linux/raid/raid1.h>
  36 #include <linux/raid/bitmap.h>
  37
  38 #define DEBUG 0
  39 #if DEBUG
  40 #define PRINTK(x...) printk(x)
  41 #else
  42 #define PRINTK(x...)
  43 #endif
  44
  45 /*
  46  * Number of guaranteed r1bios in case of extreme VM load:
  47  */
  48 #define NR_RAID1_BIOS 256
  49
  50
  51 static void unplug_slaves(mddev_t *mddev);
  52
  53 static void allow_barrier(conf_t *conf);
  54 static void lower_barrier(conf_t *conf);
  55
  56 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
  57 {
  58         struct pool_info *pi = data;
  59         r1bio_t *r1_bio;
  60         int size = offsetof(r1bio_t, bios[pi->raid_disks]);
  61
  62         /* allocate a r1bio with room for raid_disks entries in the bios array */
  63         r1_bio = kzalloc(size, gfp_flags);
  64         if (!r1_bio)
  65                 unplug_slaves(pi->mddev);
  66
  67         return r1_bio;
  68 }
  69
  70 static void r1bio_pool_free(void *r1_bio, void *data)
  71 {
  72         kfree(r1_bio);
  73 }
  74
  75 #define RESYNC_BLOCK_SIZE (64*1024)
  76 //#define RESYNC_BLOCK_SIZE PAGE_SIZE
  77 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
  78 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
  79 #define RESYNC_WINDOW (2048*1024)
  80
  81 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
  82 {
  83         struct pool_info *pi = data;
  84         struct page *page;
  85         r1bio_t *r1_bio;
  86         struct bio *bio;
  87         int i, j;
  88
  89         r1_bio = r1bio_pool_alloc(gfp_flags, pi);
  90         if (!r1_bio) {
  91                 unplug_slaves(pi->mddev);
  92                 return NULL;
  93         }
  94
  95         /*
  96          * Allocate bios : 1 for reading, n-1 for writing
  97          */
  98         for (j = pi->raid_disks ; j-- ; ) {
  99                 bio = bio_alloc(gfp_flags, RESYNC_PAGES);
 100                 if (!bio)
 101                         goto out_free_bio;
 102                 r1_bio->bios[j] = bio;
 103         }
 104         /*
 105          * Allocate RESYNC_PAGES data pages and attach them to
 106          * the first bio.
 107          * If this is a user-requested check/repair, allocate
 108          * RESYNC_PAGES for each bio.
 109          */
 110         if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
 111                 j = pi->raid_disks;
 112         else
 113                 j = 1;
 114         while(j--) {
 115                 bio = r1_bio->bios[j];
 116                 for (i = 0; i < RESYNC_PAGES; i++) {
 117                         page = alloc_page(gfp_flags);
 118                         if (unlikely(!page))
 119                                 goto out_free_pages;
 120
 121                         bio->bi_io_vec[i].bv_page = page;
 122                 }
 123         }
 124         /* If not user-requests, copy the page pointers to all bios */
 125         if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
 126                 for (i=0; i<RESYNC_PAGES ; i++)
 127                         for (j=1; j<pi->raid_disks; j++)
 128                                 r1_bio->bios[j]->bi_io_vec[i].bv_page =
 129                                         r1_bio->bios[0]->bi_io_vec[i].bv_page;
 130         }
 131
 132         r1_bio->master_bio = NULL;
 133
 134         return r1_bio;
 135
 136 out_free_pages:
 137         for (i=0; i < RESYNC_PAGES ; i++)
 138                 for (j=0 ; j < pi->raid_disks; j++)
 139                         safe_put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
 140         j = -1;
 141 out_free_bio:
 142         while ( ++j < pi->raid_disks )
 143                 bio_put(r1_bio->bios[j]);
 144         r1bio_pool_free(r1_bio, data);
 145         return NULL;
 146 }
 147
 148 static void r1buf_pool_free(void *__r1_bio, void *data)
 149 {
 150         struct pool_info *pi = data;
 151         int i,j;
 152         r1bio_t *r1bio = __r1_bio;
 153
 154         for (i = 0; i < RESYNC_PAGES; i++)
 155                 for (j = pi->raid_disks; j-- ;) {
 156                         if (j == 0 ||
 157                             r1bio->bios[j]->bi_io_vec[i].bv_page !=
 158                             r1bio->bios[0]->bi_io_vec[i].bv_page)
 159                                 safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page);
 160                 }
 161         for (i=0 ; i < pi->raid_disks; i++)
 162                 bio_put(r1bio->bios[i]);
 163
 164         r1bio_pool_free(r1bio, data);
 165 }
 166
 167 static void put_all_bios(conf_t *conf, r1bio_t *r1_bio)
 168 {
 169         int i;
 170
 171         for (i = 0; i < conf->raid_disks; i++) {
 172                 struct bio **bio = r1_bio->bios + i;
 173                 if (*bio && *bio != IO_BLOCKED)
 174                         bio_put(*bio);
 175                 *bio = NULL;
 176         }
 177 }
 178
 179 static void free_r1bio(r1bio_t *r1_bio)
 180 {
 181         conf_t *conf = mddev_to_conf(r1_bio->mddev);
 182
 183         /*
 184          * Wake up any possible resync thread that waits for the device
 185          * to go idle.
 186          */
 187         allow_barrier(conf);
 188
 189         put_all_bios(conf, r1_bio);
 190         mempool_free(r1_bio, conf->r1bio_pool);
 191 }
 192
 193 static void put_buf(r1bio_t *r1_bio)
 194 {
 195         conf_t *conf = mddev_to_conf(r1_bio->mddev);
 196         int i;
 197
 198         for (i=0; i<conf->raid_disks; i++) {
 199                 struct bio *bio = r1_bio->bios[i];
 200                 if (bio->bi_end_io)
 201                         rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
 202         }
 203
 204         mempool_free(r1_bio, conf->r1buf_pool);
 205
 206         lower_barrier(conf);
 207 }
 208
 209 static void reschedule_retry(r1bio_t *r1_bio)
 210 {
 211         unsigned long flags;
 212         mddev_t *mddev = r1_bio->mddev;
 213         conf_t *conf = mddev_to_conf(mddev);
 214
 215         spin_lock_irqsave(&conf->device_lock, flags);
 216         list_add(&r1_bio->retry_list, &conf->retry_list);
 217         conf->nr_queued ++;
 218         spin_unlock_irqrestore(&conf->device_lock, flags);
 219
 220         wake_up(&conf->wait_barrier);
 221         md_wakeup_thread(mddev->thread);
 222 }
 223
 224 /*
 225  * raid_end_bio_io() is called when we have finished servicing a mirrored
 226  * operation and are ready to return a success/failure code to the buffer
 227  * cache layer.
 228  */
 229 static void raid_end_bio_io(r1bio_t *r1_bio)
 230 {
 231         struct bio *bio = r1_bio->master_bio;
 232
 233         /* if nobody has done the final endio yet, do it now */
 234         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 235                 PRINTK(KERN_DEBUG "raid1: sync end %s on sectors %llu-%llu\n",
 236                         (bio_data_dir(bio) == WRITE) ? "write" : "read",
 237                         (unsigned long long) bio->bi_sector,
 238                         (unsigned long long) bio->bi_sector +
 239                                 (bio->bi_size >> 9) - 1);
 240
 241                 bio_endio(bio, bio->bi_size,
 242                         test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO);
 243         }
 244         free_r1bio(r1_bio);
 245 }
 246
 247 /*
 248  * Update disk head position estimator based on IRQ completion info.
 249  */
 250 static inline void update_head_pos(int disk, r1bio_t *r1_bio)
 251 {
 252         conf_t *conf = mddev_to_conf(r1_bio->mddev);
 253
 254         conf->mirrors[disk].head_position =
 255                 r1_bio->sector + (r1_bio->sectors);
 256 }
 257
 258 static int raid1_end_read_request(struct bio *bio, unsigned int bytes_done, int error)
 259 {
 260         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 261         r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
 262         int mirror;
 263         conf_t *conf = mddev_to_conf(r1_bio->mddev);
 264
 265         if (bio->bi_size)
 266                 return 1;
 267
 268         mirror = r1_bio->read_disk;
 269         /*
 270          * this branch is our 'one mirror IO has finished' event handler:
 271          */
 272         update_head_pos(mirror, r1_bio);
 273
 274         if (uptodate)
 275                 set_bit(R1BIO_Uptodate, &r1_bio->state);
 276         else {
 277                 /* If all other devices have failed, we want to return
 278                  * the error upwards rather than fail the last device.
 279                  * Here we redefine "uptodate" to mean "Don't want to retry"
 280                  */
 281                 unsigned long flags;
 282                 spin_lock_irqsave(&conf->device_lock, flags);
 283                 if (r1_bio->mddev->degraded == conf->raid_disks ||
 284                     (r1_bio->mddev->degraded == conf->raid_disks-1 &&
 285                      !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags)))
 286                         uptodate = 1;
 287                 spin_unlock_irqrestore(&conf->device_lock, flags);
 288         }
 289
 290         if (uptodate)
 291                 raid_end_bio_io(r1_bio);
 292         else {
 293                 /*
 294                  * oops, read error:
 295                  */
 296                 char b[BDEVNAME_SIZE];
 297                 if (printk_ratelimit())
 298                         printk(KERN_ERR "raid1: %s: rescheduling sector %llu\n",
 299                                bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector);
 300                 reschedule_retry(r1_bio);
 301         }
 302
 303         rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
 304         return 0;
 305 }
 306
 307 static int raid1_end_write_request(struct bio *bio, unsigned int bytes_done, int error)
 308 {
 309         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 310         r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
 311         int mirror, behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
 312         conf_t *conf = mddev_to_conf(r1_bio->mddev);
 313         struct bio *to_put = NULL;
 314
 315         if (bio->bi_size)
 316                 return 1;
 317
 318         for (mirror = 0; mirror < conf->raid_disks; mirror++)
 319                 if (r1_bio->bios[mirror] == bio)
 320                         break;
 321
 322         if (error == -EOPNOTSUPP && test_bit(R1BIO_Barrier, &r1_bio->state)) {
 323                 set_bit(BarriersNotsupp, &conf->mirrors[mirror].rdev->flags);
 324                 set_bit(R1BIO_BarrierRetry, &r1_bio->state);
 325                 r1_bio->mddev->barriers_work = 0;
 326                 /* Don't rdev_dec_pending in this branch - keep it for the retry */
 327         } else {
 328                 /*
 329                  * this branch is our 'one mirror IO has finished' event handler:
 330                  */
 331                 r1_bio->bios[mirror] = NULL;
 332                 to_put = bio;
 333                 if (!uptodate) {
 334                         md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
 335                         /* an I/O failed, we can't clear the bitmap */
 336                         set_bit(R1BIO_Degraded, &r1_bio->state);
 337                 } else
 338                         /*
 339                          * Set R1BIO_Uptodate in our master bio, so that
 340                          * we will return a good error code for to the higher
 341                          * levels even if IO on some other mirrored buffer fails.
 342                          *
 343                          * The 'master' represents the composite IO operation to
 344                          * user-side. So if something waits for IO, then it will
 345                          * wait for the 'master' bio.
 346                          */
 347                         set_bit(R1BIO_Uptodate, &r1_bio->state);
 348
 349                 update_head_pos(mirror, r1_bio);
 350
 351                 if (behind) {
 352                         if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags))
 353                                 atomic_dec(&r1_bio->behind_remaining);
 354
 355                         /* In behind mode, we ACK the master bio once the I/O has safely
 356                          * reached all non-writemostly disks. Setting the Returned bit
 357                          * ensures that this gets done only once -- we don't ever want to
 358                          * return -EIO here, instead we'll wait */
 359
 360                         if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
 361                             test_bit(R1BIO_Uptodate, &r1_bio->state)) {
 362                                 /* Maybe we can return now */
 363                                 if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 364                                         struct bio *mbio = r1_bio->master_bio;
 365                                         PRINTK(KERN_DEBUG "raid1: behind end write sectors %llu-%llu\n",
 366                                                (unsigned long long) mbio->bi_sector,
 367                                                (unsigned long long) mbio->bi_sector +
 368                                                (mbio->bi_size >> 9) - 1);
 369                                         bio_endio(mbio, mbio->bi_size, 0);
 370                                 }
 371                         }
 372                 }
 373                 rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
 374         }
 375         /*
 376          *
 377          * Let's see if all mirrored write operations have finished
 378          * already.
 379          */
 380         if (atomic_dec_and_test(&r1_bio->remaining)) {
 381                 if (test_bit(R1BIO_BarrierRetry, &r1_bio->state))
 382                         reschedule_retry(r1_bio);
 383                 else {
 384                         /* it really is the end of this request */
 385                         if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
 386                                 /* free extra copy of the data pages */
 387                                 int i = bio->bi_vcnt;
 388                                 while (i--)
 389                                         safe_put_page(bio->bi_io_vec[i].bv_page);
 390                         }
 391                         /* clear the bitmap if all writes complete successfully */
 392                         bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
 393                                         r1_bio->sectors,
 394                                         !test_bit(R1BIO_Degraded, &r1_bio->state),
 395                                         behind);
 396                         md_write_end(r1_bio->mddev);
 397                         raid_end_bio_io(r1_bio);
 398                 }
 399         }
 400
 401         if (to_put)
 402                 bio_put(to_put);
 403
 404         return 0;
 405 }
 406
 407
 408 /*
 409  * This routine returns the disk from which the requested read should
 410  * be done. There is a per-array 'next expected sequential IO' sector
 411  * number - if this matches on the next IO then we use the last disk.
 412  * There is also a per-disk 'last know head position' sector that is
 413  * maintained from IRQ contexts, both the normal and the resync IO
 414  * completion handlers update this position correctly. If there is no
 415  * perfect sequential match then we pick the disk whose head is closest.
 416  *
 417  * If there are 2 mirrors in the same 2 devices, performance degrades
 418  * because position is mirror, not device based.
 419  *
 420  * The rdev for the device selected will have nr_pending incremented.
 421  */
 422 static int read_balance(conf_t *conf, r1bio_t *r1_bio)
 423 {
 424         const unsigned long this_sector = r1_bio->sector;
 425         int new_disk = conf->last_used, disk = new_disk;
 426         int wonly_disk = -1;
 427         const int sectors = r1_bio->sectors;
 428         sector_t new_distance, current_distance;
 429         mdk_rdev_t *rdev;
 430
 431         rcu_read_lock();
 432         /*
 433          * Check if we can balance. We can balance on the whole
 434          * device if no resync is going on, or below the resync window.
 435          * We take the first readable disk when above the resync window.
 436          */
 437  retry:
 438         if (conf->mddev->recovery_cp < MaxSector &&
 439             (this_sector + sectors >= conf->next_resync)) {
 440                 /* Choose the first operation device, for consistancy */
 441                 new_disk = 0;
 442
 443                 for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
 444                      r1_bio->bios[new_disk] == IO_BLOCKED ||
 445                      !rdev || !test_bit(In_sync, &rdev->flags)
 446                              || test_bit(WriteMostly, &rdev->flags);
 447                      rdev = rcu_dereference(conf->mirrors[++new_disk].rdev)) {
 448
 449                         if (rdev && test_bit(In_sync, &rdev->flags) &&
 450                                 r1_bio->bios[new_disk] != IO_BLOCKED)
 451                                 wonly_disk = new_disk;
 452
 453                         if (new_disk == conf->raid_disks - 1) {
 454                                 new_disk = wonly_disk;
 455                                 break;
 456                         }
 457                 }
 458                 goto rb_out;
 459         }
 460
 461
 462         /* make sure the disk is operational */
 463         for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
 464              r1_bio->bios[new_disk] == IO_BLOCKED ||
 465              !rdev || !test_bit(In_sync, &rdev->flags) ||
 466                      test_bit(WriteMostly, &rdev->flags);
 467              rdev = rcu_dereference(conf->mirrors[new_disk].rdev)) {
 468
 469                 if (rdev && test_bit(In_sync, &rdev->flags) &&
 470                     r1_bio->bios[new_disk] != IO_BLOCKED)
 471                         wonly_disk = new_disk;
 472
 473                 if (new_disk <= 0)
 474                         new_disk = conf->raid_disks;
 475                 new_disk--;
 476                 if (new_disk == disk) {
 477                         new_disk = wonly_disk;
 478                         break;
 479                 }
 480         }
 481
 482         if (new_disk < 0)
 483                 goto rb_out;
 484
 485         disk = new_disk;
 486         /* now disk == new_disk == starting point for search */
 487
 488         /*
 489          * Don't change to another disk for sequential reads:
 490          */
 491         if (conf->next_seq_sect == this_sector)
 492                 goto rb_out;
 493         if (this_sector == conf->mirrors[new_disk].head_position)
 494                 goto rb_out;
 495
 496         current_distance = abs(this_sector - conf->mirrors[disk].head_position);
 497
 498         /* Find the disk whose head is closest */
 499
 500         do {
 501                 if (disk <= 0)
 502                         disk = conf->raid_disks;
 503                 disk--;
 504
 505                 rdev = rcu_dereference(conf->mirrors[disk].rdev);
 506
 507                 if (!rdev || r1_bio->bios[disk] == IO_BLOCKED ||
 508                     !test_bit(In_sync, &rdev->flags) ||
 509                     test_bit(WriteMostly, &rdev->flags))
 510                         continue;
 511
 512                 if (!atomic_read(&rdev->nr_pending)) {
 513                         new_disk = disk;
 514                         break;
 515                 }
 516                 new_distance = abs(this_sector - conf->mirrors[disk].head_position);
 517                 if (new_distance < current_distance) {
 518                         current_distance = new_distance;
 519                         new_disk = disk;
 520                 }
 521         } while (disk != conf->last_used);
 522
 523  rb_out:
 524
 525
 526         if (new_disk >= 0) {
 527                 rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
 528                 if (!rdev)
 529                         goto retry;
 530                 atomic_inc(&rdev->nr_pending);
 531                 if (!test_bit(In_sync, &rdev->flags)) {
 532                         /* cannot risk returning a device that failed
 533                          * before we inc'ed nr_pending
 534                          */
 535                         rdev_dec_pending(rdev, conf->mddev);
 536                         goto retry;
 537                 }
 538                 conf->next_seq_sect = this_sector + sectors;
 539                 conf->last_used = new_disk;
 540         }
 541         rcu_read_unlock();
 542
 543         return new_disk;
 544 }
 545
 546 static void unplug_slaves(mddev_t *mddev)
 547 {
 548         conf_t *conf = mddev_to_conf(mddev);
 549         int i;
 550
 551         rcu_read_lock();
 552         for (i=0; i<mddev->raid_disks; i++) {
 553                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
 554                 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
 555                         struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
 556
 557                         atomic_inc(&rdev->nr_pending);
 558                         rcu_read_unlock();
 559
 560                         if (r_queue->unplug_fn)
 561                                 r_queue->unplug_fn(r_queue);
 562
 563                         rdev_dec_pending(rdev, mddev);
 564                         rcu_read_lock();
 565                 }
 566         }
 567         rcu_read_unlock();
 568 }
 569
 570 static void raid1_unplug(struct request_queue *q)
 571 {
 572         mddev_t *mddev = q->queuedata;
 573
 574         unplug_slaves(mddev);
 575         md_wakeup_thread(mddev->thread);
 576 }
 577
 578 static int raid1_issue_flush(struct request_queue *q, struct gendisk *disk,
 579                              sector_t *error_sector)
 580 {
 581         mddev_t *mddev = q->queuedata;
 582         conf_t *conf = mddev_to_conf(mddev);
 583         int i, ret = 0;
 584
 585         rcu_read_lock();
 586         for (i=0; i<mddev->raid_disks && ret == 0; i++) {
 587                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
 588                 if (rdev && !test_bit(Faulty, &rdev->flags)) {
 589                         struct block_device *bdev = rdev->bdev;
 590                         struct request_queue *r_queue = bdev_get_queue(bdev);
 591
 592                         if (!r_queue->issue_flush_fn)
 593                                 ret = -EOPNOTSUPP;
 594                         else {
 595                                 atomic_inc(&rdev->nr_pending);
 596                                 rcu_read_unlock();
 597                                 ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
 598                                                               error_sector);
 599                                 rdev_dec_pending(rdev, mddev);
 600                                 rcu_read_lock();
 601                         }
 602                 }
 603         }
 604         rcu_read_unlock();
 605         return ret;
 606 }
 607
 608 static int raid1_congested(void *data, int bits)
 609 {
 610         mddev_t *mddev = data;
 611         conf_t *conf = mddev_to_conf(mddev);
 612         int i, ret = 0;
 613
 614         rcu_read_lock();
 615         for (i = 0; i < mddev->raid_disks; i++) {
 616                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
 617                 if (rdev && !test_bit(Faulty, &rdev->flags)) {
 618                         struct request_queue *q = bdev_get_queue(rdev->bdev);
 619
 620                         /* Note the '|| 1' - when read_balance prefers
 621                          * non-congested targets, it can be removed
 622                          */
 623                         if ((bits & (1<<BDI_write_congested)) || 1)
 624                                 ret |= bdi_congested(&q->backing_dev_info, bits);
 625                         else
 626                                 ret &= bdi_congested(&q->backing_dev_info, bits);
 627                 }
 628         }
 629         rcu_read_unlock();
 630         return ret;
 631 }
 632
 633
 634 /* Barriers....
 635  * Sometimes we need to suspend IO while we do something else,
 636  * either some resync/recovery, or reconfigure the array.
 637  * To do this we raise a 'barrier'.
 638  * The 'barrier' is a counter that can be raised multiple times
 639  * to count how many activities are happening which preclude
 640  * normal IO.
 641  * We can only raise the barrier if there is no pending IO.
 642  * i.e. if nr_pending == 0.
 643  * We choose only to raise the barrier if no-one is waiting for the
 644  * barrier to go down.  This means that as soon as an IO request
 645  * is ready, no other operations which require a barrier will start
 646  * until the IO request has had a chance.
 647  *
 648  * So: regular IO calls 'wait_barrier'.  When that returns there
 649  *    is no backgroup IO happening,  It must arrange to call
 650  *    allow_barrier when it has finished its IO.
 651  * backgroup IO calls must call raise_barrier.  Once that returns
 652  *    there is no normal IO happeing.  It must arrange to call
 653  *    lower_barrier when the particular background IO completes.
 654  */
 655 #define RESYNC_DEPTH 32
 656
 657 static void raise_barrier(conf_t *conf)
 658 {
 659         spin_lock_irq(&conf->resync_lock);
 660
 661         /* Wait until no block IO is waiting */
 662         wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
 663                             conf->resync_lock,
 664                             raid1_unplug(conf->mddev->queue));
 665
 666         /* block any new IO from starting */
 667         conf->barrier++;
 668
 669         /* No wait for all pending IO to complete */
 670         wait_event_lock_irq(conf->wait_barrier,
 671                             !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
 672                             conf->resync_lock,
 673                             raid1_unplug(conf->mddev->queue));
 674
 675         spin_unlock_irq(&conf->resync_lock);
 676 }
 677
 678 static void lower_barrier(conf_t *conf)
 679 {
 680         unsigned long flags;
 681         spin_lock_irqsave(&conf->resync_lock, flags);
 682         conf->barrier--;
 683         spin_unlock_irqrestore(&conf->resync_lock, flags);
 684         wake_up(&conf->wait_barrier);
 685 }
 686
 687 static void wait_barrier(conf_t *conf)
 688 {
 689         spin_lock_irq(&conf->resync_lock);
 690         if (conf->barrier) {
 691                 conf->nr_waiting++;
 692                 wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
 693                                     conf->resync_lock,
 694                                     raid1_unplug(conf->mddev->queue));
 695                 conf->nr_waiting--;
 696         }
 697         conf->nr_pending++;
 698         spin_unlock_irq(&conf->resync_lock);
 699 }
 700
 701 static void allow_barrier(conf_t *conf)
 702 {
 703         unsigned long flags;
 704         spin_lock_irqsave(&conf->resync_lock, flags);
 705         conf->nr_pending--;
 706         spin_unlock_irqrestore(&conf->resync_lock, flags);
 707         wake_up(&conf->wait_barrier);
 708 }
 709
 710 static void freeze_array(conf_t *conf)
 711 {
 712         /* stop syncio and normal IO and wait for everything to
 713          * go quite.
 714          * We increment barrier and nr_waiting, and then
 715          * wait until barrier+nr_pending match nr_queued+2
 716          */
 717         spin_lock_irq(&conf->resync_lock);
 718         conf->barrier++;
 719         conf->nr_waiting++;
 720         wait_event_lock_irq(conf->wait_barrier,
 721                             conf->barrier+conf->nr_pending == conf->nr_queued+2,
 722                             conf->resync_lock,
 723                             raid1_unplug(conf->mddev->queue));
 724         spin_unlock_irq(&conf->resync_lock);
 725 }
 726 static void unfreeze_array(conf_t *conf)
 727 {
 728         /* reverse the effect of the freeze */
 729         spin_lock_irq(&conf->resync_lock);
 730         conf->barrier--;
 731         conf->nr_waiting--;
 732         wake_up(&conf->wait_barrier);
 733         spin_unlock_irq(&conf->resync_lock);
 734 }
 735
 736
 737 /* duplicate the data pages for behind I/O */
 738 static struct page **alloc_behind_pages(struct bio *bio)
 739 {
 740         int i;
 741         struct bio_vec *bvec;
 742         struct page **pages = kzalloc(bio->bi_vcnt * sizeof(struct page *),
 743                                         GFP_NOIO);
 744         if (unlikely(!pages))
 745                 goto do_sync_io;
 746
 747         bio_for_each_segment(bvec, bio, i) {
 748                 pages[i] = alloc_page(GFP_NOIO);
 749                 if (unlikely(!pages[i]))
 750                         goto do_sync_io;
 751                 memcpy(kmap(pages[i]) + bvec->bv_offset,
 752                         kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
 753                 kunmap(pages[i]);
 754                 kunmap(bvec->bv_page);
 755         }
 756
 757         return pages;
 758
 759 do_sync_io:
 760         if (pages)
 761                 for (i = 0; i < bio->bi_vcnt && pages[i]; i++)
 762                         put_page(pages[i]);
 763         kfree(pages);
 764         PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
 765         return NULL;
 766 }
 767
 768 static int make_request(struct request_queue *q, struct bio * bio)
 769 {
 770         mddev_t *mddev = q->queuedata;
 771         conf_t *conf = mddev_to_conf(mddev);
 772         mirror_info_t *mirror;
 773         r1bio_t *r1_bio;
 774         struct bio *read_bio;
 775         int i, targets = 0, disks;
 776         mdk_rdev_t *rdev;
 777         struct bitmap *bitmap = mddev->bitmap;
 778         unsigned long flags;
 779         struct bio_list bl;
 780         struct page **behind_pages = NULL;
 781         const int rw = bio_data_dir(bio);
 782         const int do_sync = bio_sync(bio);
 783         int do_barriers;
 784
 785         /*
 786          * Register the new request and wait if the reconstruction
 787          * thread has put up a bar for new requests.
 788          * Continue immediately if no resync is active currently.
 789          * We test barriers_work *after* md_write_start as md_write_start
 790          * may cause the first superblock write, and that will check out
 791          * if barriers work.
 792          */
 793
 794         md_write_start(mddev, bio); /* wait on superblock update early */
 795
 796         if (unlikely(!mddev->barriers_work && bio_barrier(bio))) {
 797                 if (rw == WRITE)
 798                         md_write_end(mddev);
 799                 bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
 800                 return 0;
 801         }
 802
 803         wait_barrier(conf);
 804
 805         disk_stat_inc(mddev->gendisk, ios[rw]);
 806         disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
 807
 808         /*
 809          * make_request() can abort the operation when READA is being
 810          * used and no empty request is available.
 811          *
 812          */
 813         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
 814
 815         r1_bio->master_bio = bio;
 816         r1_bio->sectors = bio->bi_size >> 9;
 817         r1_bio->state = 0;
 818         r1_bio->mddev = mddev;
 819         r1_bio->sector = bio->bi_sector;
 820
 821         if (rw == READ) {
 822                 /*
 823                  * read balancing logic:
 824                  */
 825                 int rdisk = read_balance(conf, r1_bio);
 826
 827                 if (rdisk < 0) {
 828                         /* couldn't find anywhere to read from */
 829                         raid_end_bio_io(r1_bio);
 830                         return 0;
 831                 }
 832                 mirror = conf->mirrors + rdisk;
 833
 834                 r1_bio->read_disk = rdisk;
 835
 836                 read_bio = bio_clone(bio, GFP_NOIO);
 837
 838                 r1_bio->bios[rdisk] = read_bio;
 839
 840                 read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
 841                 read_bio->bi_bdev = mirror->rdev->bdev;
 842                 read_bio->bi_end_io = raid1_end_read_request;
 843                 read_bio->bi_rw = READ | do_sync;
 844                 read_bio->bi_private = r1_bio;
 845
 846                 generic_make_request(read_bio);
 847                 return 0;
 848         }
 849
 850         /*
 851          * WRITE:
 852          */
 853         /* first select target devices under spinlock and
 854          * inc refcount on their rdev.  Record them by setting
 855          * bios[x] to bio
 856          */
 857         disks = conf->raid_disks;
 858 #if 0
 859         { static int first=1;
 860         if (first) printk("First Write sector %llu disks %d\n",
 861                           (unsigned long long)r1_bio->sector, disks);
 862         first = 0;
 863         }
 864 #endif
 865         rcu_read_lock();
 866         for (i = 0;  i < disks; i++) {
 867                 if ((rdev=rcu_dereference(conf->mirrors[i].rdev)) != NULL &&
 868                     !test_bit(Faulty, &rdev->flags)) {
 869                         atomic_inc(&rdev->nr_pending);
 870                         if (test_bit(Faulty, &rdev->flags)) {
 871                                 rdev_dec_pending(rdev, mddev);
 872                                 r1_bio->bios[i] = NULL;
 873                         } else
 874                                 r1_bio->bios[i] = bio;
 875                         targets++;
 876                 } else
 877                         r1_bio->bios[i] = NULL;
 878         }
 879         rcu_read_unlock();
 880
 881         BUG_ON(targets == 0); /* we never fail the last device */
 882
 883         if (targets < conf->raid_disks) {
 884                 /* array is degraded, we will not clear the bitmap
 885                  * on I/O completion (see raid1_end_write_request) */
 886                 set_bit(R1BIO_Degraded, &r1_bio->state);
 887         }
 888
 889         /* do behind I/O ? */
 890         if (bitmap &&
 891             atomic_read(&bitmap->behind_writes) < bitmap->max_write_behind &&
 892             (behind_pages = alloc_behind_pages(bio)) != NULL)
 893                 set_bit(R1BIO_BehindIO, &r1_bio->state);
 894
 895         atomic_set(&r1_bio->remaining, 0);
 896         atomic_set(&r1_bio->behind_remaining, 0);
 897
 898         do_barriers = bio_barrier(bio);
 899         if (do_barriers)
 900                 set_bit(R1BIO_Barrier, &r1_bio->state);
 901
 902         bio_list_init(&bl);
 903         for (i = 0; i < disks; i++) {
 904                 struct bio *mbio;
 905                 if (!r1_bio->bios[i])
 906                         continue;
 907
 908                 mbio = bio_clone(bio, GFP_NOIO);
 909                 r1_bio->bios[i] = mbio;
 910
 911                 mbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset;
 912                 mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
 913                 mbio->bi_end_io = raid1_end_write_request;
 914                 mbio->bi_rw = WRITE | do_barriers | do_sync;
 915                 mbio->bi_private = r1_bio;
 916
 917                 if (behind_pages) {
 918                         struct bio_vec *bvec;
 919                         int j;
 920
 921                         /* Yes, I really want the '__' version so that
 922                          * we clear any unused pointer in the io_vec, rather
 923                          * than leave them unchanged.  This is important
 924                          * because when we come to free the pages, we won't
 925                          * know the originial bi_idx, so we just free
 926                          * them all
 927                          */
 928                         __bio_for_each_segment(bvec, mbio, j, 0)
 929                                 bvec->bv_page = behind_pages[j];
 930                         if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
 931                                 atomic_inc(&r1_bio->behind_remaining);
 932                 }
 933
 934                 atomic_inc(&r1_bio->remaining);
 935
 936                 bio_list_add(&bl, mbio);
 937         }
 938         kfree(behind_pages); /* the behind pages are attached to the bios now */
 939
 940         bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors,
 941                                 test_bit(R1BIO_BehindIO, &r1_bio->state));
 942         spin_lock_irqsave(&conf->device_lock, flags);
 943         bio_list_merge(&conf->pending_bio_list, &bl);
 944         bio_list_init(&bl);
 945
 946         blk_plug_device(mddev->queue);
 947         spin_unlock_irqrestore(&conf->device_lock, flags);
 948
 949         if (do_sync)
 950                 md_wakeup_thread(mddev->thread);
 951 #if 0
 952         while ((bio = bio_list_pop(&bl)) != NULL)
 953                 generic_make_request(bio);
 954 #endif
 955
 956         return 0;
 957 }
 958
 959 static void status(struct seq_file *seq, mddev_t *mddev)
 960 {
 961         conf_t *conf = mddev_to_conf(mddev);
 962         int i;
 963
 964         seq_printf(seq, " [%d/%d] [", conf->raid_disks,
 965                    conf->raid_disks - mddev->degraded);
 966         rcu_read_lock();
 967         for (i = 0; i < conf->raid_disks; i++) {
 968                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
 969                 seq_printf(seq, "%s",
 970                            rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
 971         }
 972         rcu_read_unlock();
 973         seq_printf(seq, "]");
 974 }
 975
 976
 977 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
 978 {
 979         char b[BDEVNAME_SIZE];
 980         conf_t *conf = mddev_to_conf(mddev);
 981
 982         /*
 983          * If it is not operational, then we have already marked it as dead
 984          * else if it is the last working disks, ignore the error, let the
 985          * next level up know.
 986          * else mark the drive as failed
 987          */
 988         if (test_bit(In_sync, &rdev->flags)
 989             && (conf->raid_disks - mddev->degraded) == 1)
 990                 /*
 991                  * Don't fail the drive, act as though we were just a
 992                  * normal single drive
 993                  */
 994                 return;
 995         if (test_and_clear_bit(In_sync, &rdev->flags)) {
 996                 unsigned long flags;
 997                 spin_lock_irqsave(&conf->device_lock, flags);
 998                 mddev->degraded++;
 999                 set_bit(Faulty, &rdev->flags);
1000                 spin_unlock_irqrestore(&conf->device_lock, flags);
1001                 /*
1002                  * if recovery is running, make sure it aborts.
1003                  */
1004                 set_bit(MD_RECOVERY_ERR, &mddev->recovery);
1005         } else
1006                 set_bit(Faulty, &rdev->flags);
1007         set_bit(MD_CHANGE_DEVS, &mddev->flags);
1008         printk(KERN_ALERT "raid1: Disk failure on %s, disabling device. \n"
1009                 "       Operation continuing on %d devices\n",
1010                 bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded);
1011 }
1012
1013 static void print_conf(conf_t *conf)
1014 {
1015         int i;
1016
1017         printk("RAID1 conf printout:\n");
1018         if (!conf) {
1019                 printk("(!conf)\n");
1020                 return;
1021         }
1022         printk(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1023                 conf->raid_disks);
1024
1025         rcu_read_lock();
1026         for (i = 0; i < conf->raid_disks; i++) {
1027                 char b[BDEVNAME_SIZE];
1028                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1029                 if (rdev)
1030                         printk(" disk %d, wo:%d, o:%d, dev:%s\n",
1031                                i, !test_bit(In_sync, &rdev->flags),
1032                                !test_bit(Faulty, &rdev->flags),
1033                                bdevname(rdev->bdev,b));
1034         }
1035         rcu_read_unlock();
1036 }
1037
1038 static void close_sync(conf_t *conf)
1039 {
1040         wait_barrier(conf);
1041         allow_barrier(conf);
1042
1043         mempool_destroy(conf->r1buf_pool);
1044         conf->r1buf_pool = NULL;
1045 }
1046
1047 static int raid1_spare_active(mddev_t *mddev)
1048 {
1049         int i;
1050         conf_t *conf = mddev->private;
1051
1052         /*
1053          * Find all failed disks within the RAID1 configuration
1054          * and mark them readable.
1055          * Called under mddev lock, so rcu protection not needed.
1056          */
1057         for (i = 0; i < conf->raid_disks; i++) {
1058                 mdk_rdev_t *rdev = conf->mirrors[i].rdev;
1059                 if (rdev
1060                     && !test_bit(Faulty, &rdev->flags)
1061                     && !test_and_set_bit(In_sync, &rdev->flags)) {
1062                         unsigned long flags;
1063                         spin_lock_irqsave(&conf->device_lock, flags);
1064                         mddev->degraded--;
1065                         spin_unlock_irqrestore(&conf->device_lock, flags);
1066                 }
1067         }
1068
1069         print_conf(conf);
1070         return 0;
1071 }
1072
1073
1074 static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
1075 {
1076         conf_t *conf = mddev->private;
1077         int found = 0;
1078         int mirror = 0;
1079         mirror_info_t *p;
1080
1081         for (mirror=0; mirror < mddev->raid_disks; mirror++)
1082                 if ( !(p=conf->mirrors+mirror)->rdev) {
1083
1084                         blk_queue_stack_limits(mddev->queue,
1085                                                rdev->bdev->bd_disk->queue);
1086                         /* as we don't honour merge_bvec_fn, we must never risk
1087                          * violating it, so limit ->max_sector to one PAGE, as
1088                          * a one page request is never in violation.
1089                          */
1090                         if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
1091                             mddev->queue->max_sectors > (PAGE_SIZE>>9))
1092                                 blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
1093
1094                         p->head_position = 0;
1095                         rdev->raid_disk = mirror;
1096                         found = 1;
1097                         /* As all devices are equivalent, we don't need a full recovery
1098                          * if this was recently any drive of the array
1099                          */
1100                         if (rdev->saved_raid_disk < 0)
1101                                 conf->fullsync = 1;
1102                         rcu_assign_pointer(p->rdev, rdev);
1103                         break;
1104                 }
1105
1106         print_conf(conf);
1107         return found;
1108 }
1109
1110 static int raid1_remove_disk(mddev_t *mddev, int number)
1111 {
1112         conf_t *conf = mddev->private;
1113         int err = 0;
1114         mdk_rdev_t *rdev;
1115         mirror_info_t *p = conf->mirrors+ number;
1116
1117         print_conf(conf);
1118         rdev = p->rdev;
1119         if (rdev) {
1120                 if (test_bit(In_sync, &rdev->flags) ||
1121                     atomic_read(&rdev->nr_pending)) {
1122                         err = -EBUSY;
1123                         goto abort;
1124                 }
1125                 p->rdev = NULL;
1126                 synchronize_rcu();
1127                 if (atomic_read(&rdev->nr_pending)) {
1128                         /* lost the race, try later */
1129                         err = -EBUSY;
1130                         p->rdev = rdev;
1131                 }
1132         }
1133 abort:
1134
1135         print_conf(conf);
1136         return err;
1137 }
1138
1139
1140 static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error)
1141 {
1142         r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
1143         int i;
1144
1145         if (bio->bi_size)
1146                 return 1;
1147
1148         for (i=r1_bio->mddev->raid_disks; i--; )
1149                 if (r1_bio->bios[i] == bio)
1150                         break;
1151         BUG_ON(i < 0);
1152         update_head_pos(i, r1_bio);
1153         /*
1154          * we have read a block, now it needs to be re-written,
1155          * or re-read if the read failed.
1156          * We don't do much here, just schedule handling by raid1d
1157          */
1158         if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1159                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1160
1161         if (atomic_dec_and_test(&r1_bio->remaining))
1162                 reschedule_retry(r1_bio);
1163         return 0;
1164 }
1165
1166 static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error)
1167 {
1168         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1169         r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
1170         mddev_t *mddev = r1_bio->mddev;
1171         conf_t *conf = mddev_to_conf(mddev);
1172         int i;
1173         int mirror=0;
1174
1175         if (bio->bi_size)
1176                 return 1;
1177
1178         for (i = 0; i < conf->raid_disks; i++)
1179                 if (r1_bio->bios[i] == bio) {
1180                         mirror = i;
1181                         break;
1182                 }
1183         if (!uptodate) {
1184                 int sync_blocks = 0;
1185                 sector_t s = r1_bio->sector;
1186                 long sectors_to_go = r1_bio->sectors;
1187                 /* make sure these bits doesn't get cleared. */
1188                 do {
1189                         bitmap_end_sync(mddev->bitmap, s,
1190                                         &sync_blocks, 1);
1191                         s += sync_blocks;
1192                         sectors_to_go -= sync_blocks;
1193                 } while (sectors_to_go > 0);
1194                 md_error(mddev, conf->mirrors[mirror].rdev);
1195         }
1196
1197         update_head_pos(mirror, r1_bio);
1198
1199         if (atomic_dec_and_test(&r1_bio->remaining)) {
1200                 md_done_sync(mddev, r1_bio->sectors, uptodate);
1201                 put_buf(r1_bio);
1202         }
1203         return 0;
1204 }
1205
1206 static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
1207 {
1208         conf_t *conf = mddev_to_conf(mddev);
1209         int i;
1210         int disks = conf->raid_disks;
1211         struct bio *bio, *wbio;
1212
1213         bio = r1_bio->bios[r1_bio->read_disk];
1214
1215
1216         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1217                 /* We have read all readable devices.  If we haven't
1218                  * got the block, then there is no hope left.
1219                  * If we have, then we want to do a comparison
1220                  * and skip the write if everything is the same.
1221                  * If any blocks failed to read, then we need to
1222                  * attempt an over-write
1223                  */
1224                 int primary;
1225                 if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1226                         for (i=0; i<mddev->raid_disks; i++)
1227                                 if (r1_bio->bios[i]->bi_end_io == end_sync_read)
1228                                         md_error(mddev, conf->mirrors[i].rdev);
1229
1230                         md_done_sync(mddev, r1_bio->sectors, 1);
1231                         put_buf(r1_bio);
1232                         return;
1233                 }
1234                 for (primary=0; primary<mddev->raid_disks; primary++)
1235                         if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1236                             test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
1237                                 r1_bio->bios[primary]->bi_end_io = NULL;
1238                                 rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1239                                 break;
1240                         }
1241                 r1_bio->read_disk = primary;
1242                 for (i=0; i<mddev->raid_disks; i++)
1243                         if (r1_bio->bios[i]->bi_end_io == end_sync_read) {
1244                                 int j;
1245                                 int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
1246                                 struct bio *pbio = r1_bio->bios[primary];
1247                                 struct bio *sbio = r1_bio->bios[i];
1248
1249                                 if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
1250                                         for (j = vcnt; j-- ; ) {
1251                                                 struct page *p, *s;
1252                                                 p = pbio->bi_io_vec[j].bv_page;
1253                                                 s = sbio->bi_io_vec[j].bv_page;
1254                                                 if (memcmp(page_address(p),
1255                                                            page_address(s),
1256                                                            PAGE_SIZE))
1257                                                         break;
1258                                         }
1259                                 } else
1260                                         j = 0;
1261                                 if (j >= 0)
1262                                         mddev->resync_mismatches += r1_bio->sectors;
1263                                 if (j < 0 || test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) {
1264                                         sbio->bi_end_io = NULL;
1265                                         rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1266                                 } else {
1267                                         /* fixup the bio for reuse */
1268                                         sbio->bi_vcnt = vcnt;
1269                                         sbio->bi_size = r1_bio->sectors << 9;
1270                                         sbio->bi_idx = 0;
1271                                         sbio->bi_phys_segments = 0;
1272                                         sbio->bi_hw_segments = 0;
1273                                         sbio->bi_hw_front_size = 0;
1274                                         sbio->bi_hw_back_size = 0;
1275                                         sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1276                                         sbio->bi_flags |= 1 << BIO_UPTODATE;
1277                                         sbio->bi_next = NULL;
1278                                         sbio->bi_sector = r1_bio->sector +
1279                                                 conf->mirrors[i].rdev->data_offset;
1280                                         sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1281                                         for (j = 0; j < vcnt ; j++)
1282                                                 memcpy(page_address(sbio->bi_io_vec[j].bv_page),
1283                                                        page_address(pbio->bi_io_vec[j].bv_page),
1284                                                        PAGE_SIZE);
1285
1286                                 }
1287                         }
1288         }
1289         if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1290                 /* ouch - failed to read all of that.
1291                  * Try some synchronous reads of other devices to get
1292                  * good data, much like with normal read errors.  Only
1293                  * read into the pages we already have so we don't
1294                  * need to re-issue the read request.
1295                  * We don't need to freeze the array, because being in an
1296                  * active sync request, there is no normal IO, and
1297                  * no overlapping syncs.
1298                  */
1299                 sector_t sect = r1_bio->sector;
1300                 int sectors = r1_bio->sectors;
1301                 int idx = 0;
1302
1303                 while(sectors) {
1304                         int s = sectors;
1305                         int d = r1_bio->read_disk;
1306                         int success = 0;
1307                         mdk_rdev_t *rdev;
1308
1309                         if (s > (PAGE_SIZE>>9))
1310                                 s = PAGE_SIZE >> 9;
1311                         do {
1312                                 if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1313                                         /* No rcu protection needed here devices
1314                                          * can only be removed when no resync is
1315                                          * active, and resync is currently active
1316                                          */
1317                                         rdev = conf->mirrors[d].rdev;
1318                                         if (sync_page_io(rdev->bdev,
1319                                                          sect + rdev->data_offset,
1320                                                          s<<9,
1321                                                          bio->bi_io_vec[idx].bv_page,
1322                                                          READ)) {
1323                                                 success = 1;
1324                                                 break;
1325                                         }
1326                                 }
1327                                 d++;
1328                                 if (d == conf->raid_disks)
1329                                         d = 0;
1330                         } while (!success && d != r1_bio->read_disk);
1331
1332                         if (success) {
1333                                 int start = d;
1334                                 /* write it back and re-read */
1335                                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1336                                 while (d != r1_bio->read_disk) {
1337                                         if (d == 0)
1338                                                 d = conf->raid_disks;
1339                                         d--;
1340                                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1341                                                 continue;
1342                                         rdev = conf->mirrors[d].rdev;
1343                                         atomic_add(s, &rdev->corrected_errors);
1344                                         if (sync_page_io(rdev->bdev,
1345                                                          sect + rdev->data_offset,
1346                                                          s<<9,
1347                                                          bio->bi_io_vec[idx].bv_page,
1348                                                          WRITE) == 0)
1349                                                 md_error(mddev, rdev);
1350                                 }
1351                                 d = start;
1352                                 while (d != r1_bio->read_disk) {
1353                                         if (d == 0)
1354                                                 d = conf->raid_disks;
1355                                         d--;
1356                                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1357                                                 continue;
1358                                         rdev = conf->mirrors[d].rdev;
1359                                         if (sync_page_io(rdev->bdev,
1360                                                          sect + rdev->data_offset,
1361                                                          s<<9,
1362                                                          bio->bi_io_vec[idx].bv_page,
1363                                                          READ) == 0)
1364                                                 md_error(mddev, rdev);
1365                                 }
1366                         } else {
1367                                 char b[BDEVNAME_SIZE];
1368                                 /* Cannot read from anywhere, array is toast */
1369                                 md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
1370                                 printk(KERN_ALERT "raid1: %s: unrecoverable I/O read error"
1371                                        " for block %llu\n",
1372                                        bdevname(bio->bi_bdev,b),
1373                                        (unsigned long long)r1_bio->sector);
1374                                 md_done_sync(mddev, r1_bio->sectors, 0);
1375                                 put_buf(r1_bio);
1376                                 return;
1377                         }
1378                         sectors -= s;
1379                         sect += s;
1380                         idx ++;
1381                 }
1382         }
1383
1384         /*
1385          * schedule writes
1386          */
1387         atomic_set(&r1_bio->remaining, 1);
1388         for (i = 0; i < disks ; i++) {
1389                 wbio = r1_bio->bios[i];
1390                 if (wbio->bi_end_io == NULL ||
1391                     (wbio->bi_end_io == end_sync_read &&
1392                      (i == r1_bio->read_disk ||
1393                       !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
1394                         continue;
1395
1396                 wbio->bi_rw = WRITE;
1397                 wbio->bi_end_io = end_sync_write;
1398                 atomic_inc(&r1_bio->remaining);
1399                 md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1400
1401                 generic_make_request(wbio);
1402         }
1403
1404         if (atomic_dec_and_test(&r1_bio->remaining)) {
1405                 /* if we're here, all write(s) have completed, so clean up */
1406                 md_done_sync(mddev, r1_bio->sectors, 1);
1407                 put_buf(r1_bio);
1408         }
1409 }
1410
1411 /*
1412  * This is a kernel thread which:
1413  *
1414  *      1.      Retries failed read operations on working mirrors.
1415  *      2.      Updates the raid superblock when problems encounter.
1416  *      3.      Performs writes following reads for array syncronising.
1417  */
1418
1419 static void fix_read_error(conf_t *conf, int read_disk,
1420                            sector_t sect, int sectors)
1421 {
1422         mddev_t *mddev = conf->mddev;
1423         while(sectors) {
1424                 int s = sectors;
1425                 int d = read_disk;
1426                 int success = 0;
1427                 int start;
1428                 mdk_rdev_t *rdev;
1429
1430                 if (s > (PAGE_SIZE>>9))
1431                         s = PAGE_SIZE >> 9;
1432
1433                 do {
1434                         /* Note: no rcu protection needed here
1435                          * as this is synchronous in the raid1d thread
1436                          * which is the thread that might remove
1437                          * a device.  If raid1d ever becomes multi-threaded....
1438                          */
1439                         rdev = conf->mirrors[d].rdev;
1440                         if (rdev &&
1441                             test_bit(In_sync, &rdev->flags) &&
1442                             sync_page_io(rdev->bdev,
1443                                          sect + rdev->data_offset,
1444                                          s<<9,
1445                                          conf->tmppage, READ))
1446                                 success = 1;
1447                         else {
1448                                 d++;
1449                                 if (d == conf->raid_disks)
1450                                         d = 0;
1451                         }
1452                 } while (!success && d != read_disk);
1453
1454                 if (!success) {
1455                         /* Cannot read from anywhere -- bye bye array */
1456                         md_error(mddev, conf->mirrors[read_disk].rdev);
1457                         break;
1458                 }
1459                 /* write it back and re-read */
1460                 start = d;
1461                 while (d != read_disk) {
1462                         if (d==0)
1463                                 d = conf->raid_disks;
1464                         d--;
1465                         rdev = conf->mirrors[d].rdev;
1466                         if (rdev &&
1467                             test_bit(In_sync, &rdev->flags)) {
1468                                 if (sync_page_io(rdev->bdev,
1469                                                  sect + rdev->data_offset,
1470                                                  s<<9, conf->tmppage, WRITE)
1471                                     == 0)
1472                                         /* Well, this device is dead */
1473                                         md_error(mddev, rdev);
1474                         }
1475                 }
1476                 d = start;
1477                 while (d != read_disk) {
1478                         char b[BDEVNAME_SIZE];
1479                         if (d==0)
1480                                 d = conf->raid_disks;
1481                         d--;
1482                         rdev = conf->mirrors[d].rdev;
1483                         if (rdev &&
1484                             test_bit(In_sync, &rdev->flags)) {
1485                                 if (sync_page_io(rdev->bdev,
1486                                                  sect + rdev->data_offset,
1487                                                  s<<9, conf->tmppage, READ)
1488                                     == 0)
1489                                         /* Well, this device is dead */
1490                                         md_error(mddev, rdev);
1491                                 else {
1492                                         atomic_add(s, &rdev->corrected_errors);
1493                                         printk(KERN_INFO
1494                                                "raid1:%s: read error corrected "
1495                                                "(%d sectors at %llu on %s)\n",
1496                                                mdname(mddev), s,
1497                                                (unsigned long long)(sect +
1498                                                    rdev->data_offset),
1499                                                bdevname(rdev->bdev, b));
1500                                 }
1501                         }
1502                 }
1503                 sectors -= s;
1504                 sect += s;
1505         }
1506 }
1507
1508 static void raid1d(mddev_t *mddev)
1509 {
1510         r1bio_t *r1_bio;
1511         struct bio *bio;
1512         unsigned long flags;
1513         conf_t *conf = mddev_to_conf(mddev);
1514         struct list_head *head = &conf->retry_list;
1515         int unplug=0;
1516         mdk_rdev_t *rdev;
1517
1518         md_check_recovery(mddev);
1519
1520         for (;;) {
1521                 char b[BDEVNAME_SIZE];
1522                 spin_lock_irqsave(&conf->device_lock, flags);
1523
1524                 if (conf->pending_bio_list.head) {
1525                         bio = bio_list_get(&conf->pending_bio_list);
1526                         blk_remove_plug(mddev->queue);
1527                         spin_unlock_irqrestore(&conf->device_lock, flags);
1528                         /* flush any pending bitmap writes to disk before proceeding w/ I/O */
1529                         bitmap_unplug(mddev->bitmap);
1530
1531                         while (bio) { /* submit pending writes */
1532                                 struct bio *next = bio->bi_next;
1533                                 bio->bi_next = NULL;
1534                                 generic_make_request(bio);
1535                                 bio = next;
1536                         }
1537                         unplug = 1;
1538
1539                         continue;
1540                 }
1541
1542                 if (list_empty(head))
1543                         break;
1544                 r1_bio = list_entry(head->prev, r1bio_t, retry_list);
1545                 list_del(head->prev);
1546                 conf->nr_queued--;
1547                 spin_unlock_irqrestore(&conf->device_lock, flags);
1548
1549                 mddev = r1_bio->mddev;
1550                 conf = mddev_to_conf(mddev);
1551                 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
1552                         sync_request_write(mddev, r1_bio);
1553                         unplug = 1;
1554                 } else if (test_bit(R1BIO_BarrierRetry, &r1_bio->state)) {
1555                         /* some requests in the r1bio were BIO_RW_BARRIER
1556                          * requests which failed with -EOPNOTSUPP.  Hohumm..
1557                          * Better resubmit without the barrier.
1558                          * We know which devices to resubmit for, because
1559                          * all others have had their bios[] entry cleared.
1560                          * We already have a nr_pending reference on these rdevs.
1561                          */
1562                         int i;
1563                         const int do_sync = bio_sync(r1_bio->master_bio);
1564                         clear_bit(R1BIO_BarrierRetry, &r1_bio->state);
1565                         clear_bit(R1BIO_Barrier, &r1_bio->state);
1566                         for (i=0; i < conf->raid_disks; i++)
1567                                 if (r1_bio->bios[i])
1568                                         atomic_inc(&r1_bio->remaining);
1569                         for (i=0; i < conf->raid_disks; i++)
1570                                 if (r1_bio->bios[i]) {
1571                                         struct bio_vec *bvec;
1572                                         int j;
1573
1574                                         bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
1575                                         /* copy pages from the failed bio, as
1576                                          * this might be a write-behind device */
1577                                         __bio_for_each_segment(bvec, bio, j, 0)
1578                                                 bvec->bv_page = bio_iovec_idx(r1_bio->bios[i], j)->bv_page;
1579                                         bio_put(r1_bio->bios[i]);
1580                                         bio->bi_sector = r1_bio->sector +
1581                                                 conf->mirrors[i].rdev->data_offset;
1582                                         bio->bi_bdev = conf->mirrors[i].rdev->bdev;
1583                                         bio->bi_end_io = raid1_end_write_request;
1584                                         bio->bi_rw = WRITE | do_sync;
1585                                         bio->bi_private = r1_bio;
1586                                         r1_bio->bios[i] = bio;
1587                                         generic_make_request(bio);
1588                                 }
1589                 } else {
1590                         int disk;
1591
1592                         /* we got a read error. Maybe the drive is bad.  Maybe just
1593                          * the block and we can fix it.
1594                          * We freeze all other IO, and try reading the block from
1595                          * other devices.  When we find one, we re-write
1596                          * and check it that fixes the read error.
1597                          * This is all done synchronously while the array is
1598                          * frozen
1599                          */
1600                         if (mddev->ro == 0) {
1601                                 freeze_array(conf);
1602                                 fix_read_error(conf, r1_bio->read_disk,
1603                                                r1_bio->sector,
1604                                                r1_bio->sectors);
1605                                 unfreeze_array(conf);
1606                         }
1607
1608                         bio = r1_bio->bios[r1_bio->read_disk];
1609                         if ((disk=read_balance(conf, r1_bio)) == -1) {
1610                                 printk(KERN_ALERT "raid1: %s: unrecoverable I/O"
1611                                        " read error for block %llu\n",
1612                                        bdevname(bio->bi_bdev,b),
1613                                        (unsigned long long)r1_bio->sector);
1614                                 raid_end_bio_io(r1_bio);
1615                         } else {
1616                                 const int do_sync = bio_sync(r1_bio->master_bio);
1617                                 r1_bio->bios[r1_bio->read_disk] =
1618                                         mddev->ro ? IO_BLOCKED : NULL;
1619                                 r1_bio->read_disk = disk;
1620                                 bio_put(bio);
1621                                 bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
1622                                 r1_bio->bios[r1_bio->read_disk] = bio;
1623                                 rdev = conf->mirrors[disk].rdev;
1624                                 if (printk_ratelimit())
1625                                         printk(KERN_ERR "raid1: %s: redirecting sector %llu to"
1626                                                " another mirror\n",
1627                                                bdevname(rdev->bdev,b),
1628                                                (unsigned long long)r1_bio->sector);
1629                                 bio->bi_sector = r1_bio->sector + rdev->data_offset;
1630                                 bio->bi_bdev = rdev->bdev;
1631                                 bio->bi_end_io = raid1_end_read_request;
1632                                 bio->bi_rw = READ | do_sync;
1633                                 bio->bi_private = r1_bio;
1634                                 unplug = 1;
1635                                 generic_make_request(bio);
1636                         }
1637                 }
1638         }
1639         spin_unlock_irqrestore(&conf->device_lock, flags);
1640         if (unplug)
1641                 unplug_slaves(mddev);
1642 }
1643
1644
1645 static int init_resync(conf_t *conf)
1646 {
1647         int buffs;
1648
1649         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1650         BUG_ON(conf->r1buf_pool);
1651         conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
1652                                           conf->poolinfo);
1653         if (!conf->r1buf_pool)
1654                 return -ENOMEM;
1655         conf->next_resync = 0;
1656         return 0;
1657 }
1658
1659 /*
1660  * perform a "sync" on one "block"
1661  *
1662  * We need to make sure that no normal I/O request - particularly write
1663  * requests - conflict with active sync requests.
1664  *
1665  * This is achieved by tracking pending requests and a 'barrier' concept
1666  * that can be installed to exclude normal IO requests.
1667  */
1668
1669 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
1670 {
1671         conf_t *conf = mddev_to_conf(mddev);
1672         r1bio_t *r1_bio;
1673         struct bio *bio;
1674         sector_t max_sector, nr_sectors;
1675         int disk = -1;
1676         int i;
1677         int wonly = -1;
1678         int write_targets = 0, read_targets = 0;
1679         int sync_blocks;
1680         int still_degraded = 0;
1681
1682         if (!conf->r1buf_pool)
1683         {
1684 /*
1685                 printk("sync start - bitmap %p\n", mddev->bitmap);
1686 */
1687                 if (init_resync(conf))
1688                         return 0;
1689         }
1690
1691         max_sector = mddev->size << 1;
1692         if (sector_nr >= max_sector) {
1693                 /* If we aborted, we need to abort the
1694                  * sync on the 'current' bitmap chunk (there will
1695                  * only be one in raid1 resync.
1696                  * We can find the current addess in mddev->curr_resync
1697                  */
1698                 if (mddev->curr_resync < max_sector) /* aborted */
1699                         bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1700                                                 &sync_blocks, 1);
1701                 else /* completed sync */
1702                         conf->fullsync = 0;
1703
1704                 bitmap_close_sync(mddev->bitmap);
1705                 close_sync(conf);
1706                 return 0;
1707         }
1708
1709         if (mddev->bitmap == NULL &&
1710             mddev->recovery_cp == MaxSector &&
1711             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
1712             conf->fullsync == 0) {
1713                 *skipped = 1;
1714                 return max_sector - sector_nr;
1715         }
1716         /* before building a request, check if we can skip these blocks..
1717          * This call the bitmap_start_sync doesn't actually record anything
1718          */
1719         if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
1720             !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1721                 /* We can skip this block, and probably several more */
1722                 *skipped = 1;
1723                 return sync_blocks;
1724         }
1725         /*
1726          * If there is non-resync activity waiting for a turn,
1727          * and resync is going fast enough,
1728          * then let it though before starting on this new sync request.
1729          */
1730         if (!go_faster && conf->nr_waiting)
1731                 msleep_interruptible(1000);
1732
1733         raise_barrier(conf);
1734
1735         conf->next_resync = sector_nr;
1736
1737         r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
1738         rcu_read_lock();
1739         /*
1740          * If we get a correctably read error during resync or recovery,
1741          * we might want to read from a different device.  So we
1742          * flag all drives that could conceivably be read from for READ,
1743          * and any others (which will be non-In_sync devices) for WRITE.
1744          * If a read fails, we try reading from something else for which READ
1745          * is OK.
1746          */
1747
1748         r1_bio->mddev = mddev;
1749         r1_bio->sector = sector_nr;
1750         r1_bio->state = 0;
1751         set_bit(R1BIO_IsSync, &r1_bio->state);
1752
1753         for (i=0; i < conf->raid_disks; i++) {
1754                 mdk_rdev_t *rdev;
1755                 bio = r1_bio->bios[i];
1756
1757                 /* take from bio_init */
1758                 bio->bi_next = NULL;
1759                 bio->bi_flags |= 1 << BIO_UPTODATE;
1760                 bio->bi_rw = READ;
1761                 bio->bi_vcnt = 0;
1762                 bio->bi_idx = 0;
1763                 bio->bi_phys_segments = 0;
1764                 bio->bi_hw_segments = 0;
1765                 bio->bi_size = 0;
1766                 bio->bi_end_io = NULL;
1767                 bio->bi_private = NULL;
1768
1769                 rdev = rcu_dereference(conf->mirrors[i].rdev);
1770                 if (rdev == NULL ||
1771                            test_bit(Faulty, &rdev->flags)) {
1772                         still_degraded = 1;
1773                         continue;
1774                 } else if (!test_bit(In_sync, &rdev->flags)) {
1775                         bio->bi_rw = WRITE;
1776                         bio->bi_end_io = end_sync_write;
1777                         write_targets ++;
1778                 } else {
1779                         /* may need to read from here */
1780                         bio->bi_rw = READ;
1781                         bio->bi_end_io = end_sync_read;
1782                         if (test_bit(WriteMostly, &rdev->flags)) {
1783                                 if (wonly < 0)
1784                                         wonly = i;
1785                         } else {
1786                                 if (disk < 0)
1787                                         disk = i;
1788                         }
1789                         read_targets++;
1790                 }
1791                 atomic_inc(&rdev->nr_pending);
1792                 bio->bi_sector = sector_nr + rdev->data_offset;
1793                 bio->bi_bdev = rdev->bdev;
1794                 bio->bi_private = r1_bio;
1795         }
1796         rcu_read_unlock();
1797         if (disk < 0)
1798                 disk = wonly;
1799         r1_bio->read_disk = disk;
1800
1801         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
1802                 /* extra read targets are also write targets */
1803                 write_targets += read_targets-1;
1804
1805         if (write_targets == 0 || read_targets == 0) {
1806                 /* There is nowhere to write, so all non-sync
1807                  * drives must be failed - so we are finished
1808                  */
1809                 sector_t rv = max_sector - sector_nr;
1810                 *skipped = 1;
1811                 put_buf(r1_bio);
1812                 return rv;
1813         }
1814
1815         nr_sectors = 0;
1816         sync_blocks = 0;
1817         do {
1818                 struct page *page;
1819                 int len = PAGE_SIZE;
1820                 if (sector_nr + (len>>9) > max_sector)
1821                         len = (max_sector - sector_nr) << 9;
1822                 if (len == 0)
1823                         break;
1824                 if (sync_blocks == 0) {
1825                         if (!bitmap_start_sync(mddev->bitmap, sector_nr,
1826                                                &sync_blocks, still_degraded) &&
1827                             !conf->fullsync &&
1828                             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1829                                 break;
1830                         BUG_ON(sync_blocks < (PAGE_SIZE>>9));
1831                         if (len > (sync_blocks<<9))
1832                                 len = sync_blocks<<9;
1833                 }
1834
1835                 for (i=0 ; i < conf->raid_disks; i++) {
1836                         bio = r1_bio->bios[i];
1837                         if (bio->bi_end_io) {
1838                                 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
1839                                 if (bio_add_page(bio, page, len, 0) == 0) {
1840                                         /* stop here */
1841                                         bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
1842                                         while (i > 0) {
1843                                                 i--;
1844                                                 bio = r1_bio->bios[i];
1845                                                 if (bio->bi_end_io==NULL)
1846                                                         continue;
1847                                                 /* remove last page from this bio */
1848                                                 bio->bi_vcnt--;
1849                                                 bio->bi_size -= len;
1850                                                 bio->bi_flags &= ~(1<< BIO_SEG_VALID);
1851                                         }
1852                                         goto bio_full;
1853                                 }
1854                         }
1855                 }
1856                 nr_sectors += len>>9;
1857                 sector_nr += len>>9;
1858                 sync_blocks -= (len>>9);
1859         } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
1860  bio_full:
1861         r1_bio->sectors = nr_sectors;
1862
1863         /* For a user-requested sync, we read all readable devices and do a
1864          * compare
1865          */
1866         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1867                 atomic_set(&r1_bio->remaining, read_targets);
1868                 for (i=0; i<conf->raid_disks; i++) {
1869                         bio = r1_bio->bios[i];
1870                         if (bio->bi_end_io == end_sync_read) {
1871                                 md_sync_acct(bio->bi_bdev, nr_sectors);
1872                                 generic_make_request(bio);
1873                         }
1874                 }
1875         } else {
1876                 atomic_set(&r1_bio->remaining, 1);
1877                 bio = r1_bio->bios[r1_bio->read_disk];
1878                 md_sync_acct(bio->bi_bdev, nr_sectors);
1879                 generic_make_request(bio);
1880
1881         }
1882         return nr_sectors;
1883 }
1884
1885 static int run(mddev_t *mddev)
1886 {
1887         conf_t *conf;
1888         int i, j, disk_idx;
1889         mirror_info_t *disk;
1890         mdk_rdev_t *rdev;
1891         struct list_head *tmp;
1892
1893         if (mddev->level != 1) {
1894                 printk("raid1: %s: raid level not set to mirroring (%d)\n",
1895                        mdname(mddev), mddev->level);
1896                 goto out;
1897         }
1898         if (mddev->reshape_position != MaxSector) {
1899                 printk("raid1: %s: reshape_position set but not supported\n",
1900                        mdname(mddev));
1901                 goto out;
1902         }
1903         /*
1904          * copy the already verified devices into our private RAID1
1905          * bookkeeping area. [whatever we allocate in run(),
1906          * should be freed in stop()]
1907          */
1908         conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
1909         mddev->private = conf;
1910         if (!conf)
1911                 goto out_no_mem;
1912
1913         conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
1914                                  GFP_KERNEL);
1915         if (!conf->mirrors)
1916                 goto out_no_mem;
1917
1918         conf->tmppage = alloc_page(GFP_KERNEL);
1919         if (!conf->tmppage)
1920                 goto out_no_mem;
1921
1922         conf->poolinfo = kmalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
1923         if (!conf->poolinfo)
1924                 goto out_no_mem;
1925         conf->poolinfo->mddev = mddev;
1926         conf->poolinfo->raid_disks = mddev->raid_disks;
1927         conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
1928                                           r1bio_pool_free,
1929                                           conf->poolinfo);
1930         if (!conf->r1bio_pool)
1931                 goto out_no_mem;
1932
1933         ITERATE_RDEV(mddev, rdev, tmp) {
1934                 disk_idx = rdev->raid_disk;
1935                 if (disk_idx >= mddev->raid_disks
1936                     || disk_idx < 0)
1937                         continue;
1938                 disk = conf->mirrors + disk_idx;
1939
1940                 disk->rdev = rdev;
1941
1942                 blk_queue_stack_limits(mddev->queue,
1943                                        rdev->bdev->bd_disk->queue);
1944                 /* as we don't honour merge_bvec_fn, we must never risk
1945                  * violating it, so limit ->max_sector to one PAGE, as
1946                  * a one page request is never in violation.
1947                  */
1948                 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
1949                     mddev->queue->max_sectors > (PAGE_SIZE>>9))
1950                         blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
1951
1952                 disk->head_position = 0;
1953         }
1954         conf->raid_disks = mddev->raid_disks;
1955         conf->mddev = mddev;
1956         spin_lock_init(&conf->device_lock);
1957         INIT_LIST_HEAD(&conf->retry_list);
1958
1959         spin_lock_init(&conf->resync_lock);
1960         init_waitqueue_head(&conf->wait_barrier);
1961
1962         bio_list_init(&conf->pending_bio_list);
1963         bio_list_init(&conf->flushing_bio_list);
1964
1965
1966         mddev->degraded = 0;
1967         for (i = 0; i < conf->raid_disks; i++) {
1968
1969                 disk = conf->mirrors + i;
1970
1971                 if (!disk->rdev ||
1972                     !test_bit(In_sync, &disk->rdev->flags)) {
1973                         disk->head_position = 0;
1974                         mddev->degraded++;
1975                         if (disk->rdev)
1976                                 conf->fullsync = 1;
1977                 }
1978         }
1979         if (mddev->degraded == conf->raid_disks) {
1980                 printk(KERN_ERR "raid1: no operational mirrors for %s\n",
1981                         mdname(mddev));
1982                 goto out_free_conf;
1983         }
1984         if (conf->raid_disks - mddev->degraded == 1)
1985                 mddev->recovery_cp = MaxSector;
1986
1987         /*
1988          * find the first working one and use it as a starting point
1989          * to read balancing.
1990          */
1991         for (j = 0; j < conf->raid_disks &&
1992                      (!conf->mirrors[j].rdev ||
1993                       !test_bit(In_sync, &conf->mirrors[j].rdev->flags)) ; j++)
1994                 /* nothing */;
1995         conf->last_used = j;
1996
1997
1998         mddev->thread = md_register_thread(raid1d, mddev, "%s_raid1");
1999         if (!mddev->thread) {
2000                 printk(KERN_ERR
2001                        "raid1: couldn't allocate thread for %s\n",
2002                        mdname(mddev));
2003                 goto out_free_conf;
2004         }
2005
2006         printk(KERN_INFO
2007                 "raid1: raid set %s active with %d out of %d mirrors\n",
2008                 mdname(mddev), mddev->raid_disks - mddev->degraded,
2009                 mddev->raid_disks);
2010         /*
2011          * Ok, everything is just fine now
2012          */
2013         mddev->array_size = mddev->size;
2014
2015         mddev->queue->unplug_fn = raid1_unplug;
2016         mddev->queue->issue_flush_fn = raid1_issue_flush;
2017         mddev->queue->backing_dev_info.congested_fn = raid1_congested;
2018         mddev->queue->backing_dev_info.congested_data = mddev;
2019
2020         return 0;
2021
2022 out_no_mem:
2023         printk(KERN_ERR "raid1: couldn't allocate memory for %s\n",
2024                mdname(mddev));
2025
2026 out_free_conf:
2027         if (conf) {
2028                 if (conf->r1bio_pool)
2029                         mempool_destroy(conf->r1bio_pool);
2030                 kfree(conf->mirrors);
2031                 safe_put_page(conf->tmppage);
2032                 kfree(conf->poolinfo);
2033                 kfree(conf);
2034                 mddev->private = NULL;
2035         }
2036 out:
2037         return -EIO;
2038 }
2039
2040 static int stop(mddev_t *mddev)
2041 {
2042         conf_t *conf = mddev_to_conf(mddev);
2043         struct bitmap *bitmap = mddev->bitmap;
2044         int behind_wait = 0;
2045
2046         /* wait for behind writes to complete */
2047         while (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
2048                 behind_wait++;
2049                 printk(KERN_INFO "raid1: behind writes in progress on device %s, waiting to stop (%d)\n", mdname(mddev), behind_wait);
2050                 set_current_state(TASK_UNINTERRUPTIBLE);
2051                 schedule_timeout(HZ); /* wait a second */
2052                 /* need to kick something here to make sure I/O goes? */
2053         }
2054
2055         md_unregister_thread(mddev->thread);
2056         mddev->thread = NULL;
2057         blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
2058         if (conf->r1bio_pool)
2059                 mempool_destroy(conf->r1bio_pool);
2060         kfree(conf->mirrors);
2061         kfree(conf->poolinfo);
2062         kfree(conf);
2063         mddev->private = NULL;
2064         return 0;
2065 }
2066
2067 static int raid1_resize(mddev_t *mddev, sector_t sectors)
2068 {
2069         /* no resync is happening, and there is enough space
2070          * on all devices, so we can resize.
2071          * We need to make sure resync covers any new space.
2072          * If the array is shrinking we should possibly wait until
2073          * any io in the removed space completes, but it hardly seems
2074          * worth it.
2075          */
2076         mddev->array_size = sectors>>1;
2077         set_capacity(mddev->gendisk, mddev->array_size << 1);
2078         mddev->changed = 1;
2079         if (mddev->array_size > mddev->size && mddev->recovery_cp == MaxSector) {
2080                 mddev->recovery_cp = mddev->size << 1;
2081                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2082         }
2083         mddev->size = mddev->array_size;
2084         mddev->resync_max_sectors = sectors;
2085         return 0;
2086 }
2087
2088 static int raid1_reshape(mddev_t *mddev)
2089 {
2090         /* We need to:
2091          * 1/ resize the r1bio_pool
2092          * 2/ resize conf->mirrors
2093          *
2094          * We allocate a new r1bio_pool if we can.
2095          * Then raise a device barrier and wait until all IO stops.
2096          * Then resize conf->mirrors and swap in the new r1bio pool.
2097          *
2098          * At the same time, we "pack" the devices so that all the missing
2099          * devices have the higher raid_disk numbers.
2100          */
2101         mempool_t *newpool, *oldpool;
2102         struct pool_info *newpoolinfo;
2103         mirror_info_t *newmirrors;
2104         conf_t *conf = mddev_to_conf(mddev);
2105         int cnt, raid_disks;
2106         unsigned long flags;
2107         int d, d2;
2108
2109         /* Cannot change chunk_size, layout, or level */
2110         if (mddev->chunk_size != mddev->new_chunk ||
2111             mddev->layout != mddev->new_layout ||
2112             mddev->level != mddev->new_level) {
2113                 mddev->new_chunk = mddev->chunk_size;
2114                 mddev->new_layout = mddev->layout;
2115                 mddev->new_level = mddev->level;
2116                 return -EINVAL;
2117         }
2118
2119         md_allow_write(mddev);
2120
2121         raid_disks = mddev->raid_disks + mddev->delta_disks;
2122
2123         if (raid_disks < conf->raid_disks) {
2124                 cnt=0;
2125                 for (d= 0; d < conf->raid_disks; d++)
2126                         if (conf->mirrors[d].rdev)
2127                                 cnt++;
2128                 if (cnt > raid_disks)
2129                         return -EBUSY;
2130         }
2131
2132         newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
2133         if (!newpoolinfo)
2134                 return -ENOMEM;
2135         newpoolinfo->mddev = mddev;
2136         newpoolinfo->raid_disks = raid_disks;
2137
2138         newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2139                                  r1bio_pool_free, newpoolinfo);
2140         if (!newpool) {
2141                 kfree(newpoolinfo);
2142                 return -ENOMEM;
2143         }
2144         newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
2145         if (!newmirrors) {
2146                 kfree(newpoolinfo);
2147                 mempool_destroy(newpool);
2148                 return -ENOMEM;
2149         }
2150
2151         raise_barrier(conf);
2152
2153         /* ok, everything is stopped */
2154         oldpool = conf->r1bio_pool;
2155         conf->r1bio_pool = newpool;
2156
2157         for (d=d2=0; d < conf->raid_disks; d++)
2158                 if (conf->mirrors[d].rdev) {
2159                         conf->mirrors[d].rdev->raid_disk = d2;
2160                         newmirrors[d2++].rdev = conf->mirrors[d].rdev;
2161                 }
2162         kfree(conf->mirrors);
2163         conf->mirrors = newmirrors;
2164         kfree(conf->poolinfo);
2165         conf->poolinfo = newpoolinfo;
2166
2167         spin_lock_irqsave(&conf->device_lock, flags);
2168         mddev->degraded += (raid_disks - conf->raid_disks);
2169         spin_unlock_irqrestore(&conf->device_lock, flags);
2170         conf->raid_disks = mddev->raid_disks = raid_disks;
2171         mddev->delta_disks = 0;
2172
2173         conf->last_used = 0; /* just make sure it is in-range */
2174         lower_barrier(conf);
2175
2176         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2177         md_wakeup_thread(mddev->thread);
2178
2179         mempool_destroy(oldpool);
2180         return 0;
2181 }
2182
2183 static void raid1_quiesce(mddev_t *mddev, int state)
2184 {
2185         conf_t *conf = mddev_to_conf(mddev);
2186
2187         switch(state) {
2188         case 1:
2189                 raise_barrier(conf);
2190                 break;
2191         case 0:
2192                 lower_barrier(conf);
2193                 break;
2194         }
2195 }
2196
2197
2198 static struct mdk_personality raid1_personality =
2199 {
2200         .name           = "raid1",
2201         .level          = 1,
2202         .owner          = THIS_MODULE,
2203         .make_request   = make_request,
2204         .run            = run,
2205         .stop           = stop,
2206         .status         = status,
2207         .error_handler  = error,
2208         .hot_add_disk   = raid1_add_disk,
2209         .hot_remove_disk= raid1_remove_disk,
2210         .spare_active   = raid1_spare_active,
2211         .sync_request   = sync_request,
2212         .resize         = raid1_resize,
2213         .check_reshape  = raid1_reshape,
2214         .quiesce        = raid1_quiesce,
2215 };
2216
2217 static int __init raid_init(void)
2218 {
2219         return register_md_personality(&raid1_personality);
2220 }
2221
2222 static void raid_exit(void)
2223 {
2224         unregister_md_personality(&raid1_personality);
2225 }
2226
2227 module_init(raid_init);
2228 module_exit(raid_exit);
2229 MODULE_LICENSE("GPL");
2230 MODULE_ALIAS("md-personality-3"); /* RAID1 */
2231 MODULE_ALIAS("md-raid1");
2232 MODULE_ALIAS("md-level-1");