err.no Git - linux-2.6/blob - drivers/md/raid1.c

   1 /*
   2  * raid1.c : Multiple Devices driver for Linux
   3  *
   4  * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat
   5  *
   6  * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman
   7  *
   8  * RAID-1 management functions.
   9  *
  10  * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000
  11  *
  12  * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
  13  * Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
  14  *
  15  * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support
  16  * bitmapped intelligence in resync:
  17  *
  18  *      - bitmap marked during normal i/o
  19  *      - bitmap used to skip nondirty blocks during sync
  20  *
  21  * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology:
  22  * - persistent bitmap code
  23  *
  24  * This program is free software; you can redistribute it and/or modify
  25  * it under the terms of the GNU General Public License as published by
  26  * the Free Software Foundation; either version 2, or (at your option)
  27  * any later version.
  28  *
  29  * You should have received a copy of the GNU General Public License
  30  * (for example /usr/src/linux/COPYING); if not, write to the Free
  31  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  32  */
  33
  34 #include "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 static mdk_personality_t raid1_personality;
  51
  52 static void unplug_slaves(mddev_t *mddev);
  53
  54 static void allow_barrier(conf_t *conf);
  55 static void lower_barrier(conf_t *conf);
  56
  57 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
  58 {
  59         struct pool_info *pi = data;
  60         r1bio_t *r1_bio;
  61         int size = offsetof(r1bio_t, bios[pi->raid_disks]);
  62
  63         /* allocate a r1bio with room for raid_disks entries in the bios array */
  64         r1_bio = kzalloc(size, gfp_flags);
  65         if (!r1_bio)
  66                 unplug_slaves(pi->mddev);
  67
  68         return r1_bio;
  69 }
  70
  71 static void r1bio_pool_free(void *r1_bio, void *data)
  72 {
  73         kfree(r1_bio);
  74 }
  75
  76 #define RESYNC_BLOCK_SIZE (64*1024)
  77 //#define RESYNC_BLOCK_SIZE PAGE_SIZE
  78 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
  79 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
  80 #define RESYNC_WINDOW (2048*1024)
  81
  82 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
  83 {
  84         struct pool_info *pi = data;
  85         struct page *page;
  86         r1bio_t *r1_bio;
  87         struct bio *bio;
  88         int i, j;
  89
  90         r1_bio = r1bio_pool_alloc(gfp_flags, pi);
  91         if (!r1_bio) {
  92                 unplug_slaves(pi->mddev);
  93                 return NULL;
  94         }
  95
  96         /*
  97          * Allocate bios : 1 for reading, n-1 for writing
  98          */
  99         for (j = pi->raid_disks ; j-- ; ) {
 100                 bio = bio_alloc(gfp_flags, RESYNC_PAGES);
 101                 if (!bio)
 102                         goto out_free_bio;
 103                 r1_bio->bios[j] = bio;
 104         }
 105         /*
 106          * Allocate RESYNC_PAGES data pages and attach them to
 107          * the first bio.
 108          * If this is a user-requested check/repair, allocate
 109          * RESYNC_PAGES for each bio.
 110          */
 111         if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
 112                 j = pi->raid_disks;
 113         else
 114                 j = 1;
 115         while(j--) {
 116                 bio = r1_bio->bios[j];
 117                 for (i = 0; i < RESYNC_PAGES; i++) {
 118                         page = alloc_page(gfp_flags);
 119                         if (unlikely(!page))
 120                                 goto out_free_pages;
 121
 122                         bio->bi_io_vec[i].bv_page = page;
 123                 }
 124         }
 125         /* If not user-requests, copy the page pointers to all bios */
 126         if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
 127                 for (i=0; i<RESYNC_PAGES ; i++)
 128                         for (j=1; j<pi->raid_disks; j++)
 129                                 r1_bio->bios[j]->bi_io_vec[i].bv_page =
 130                                         r1_bio->bios[0]->bi_io_vec[i].bv_page;
 131         }
 132
 133         r1_bio->master_bio = NULL;
 134
 135         return r1_bio;
 136
 137 out_free_pages:
 138         for (i=0; i < RESYNC_PAGES ; i++)
 139                 for (j=0 ; j < pi->raid_disks; j++)
 140                         put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
 141         j = -1;
 142 out_free_bio:
 143         while ( ++j < pi->raid_disks )
 144                 bio_put(r1_bio->bios[j]);
 145         r1bio_pool_free(r1_bio, data);
 146         return NULL;
 147 }
 148
 149 static void r1buf_pool_free(void *__r1_bio, void *data)
 150 {
 151         struct pool_info *pi = data;
 152         int i,j;
 153         r1bio_t *r1bio = __r1_bio;
 154
 155         for (i = 0; i < RESYNC_PAGES; i++)
 156                 for (j = pi->raid_disks; j-- ;) {
 157                         if (j == 0 ||
 158                             r1bio->bios[j]->bi_io_vec[i].bv_page !=
 159                             r1bio->bios[0]->bi_io_vec[i].bv_page)
 160                                 put_page(r1bio->bios[j]->bi_io_vec[i].bv_page);
 161                 }
 162         for (i=0 ; i < pi->raid_disks; i++)
 163                 bio_put(r1bio->bios[i]);
 164
 165         r1bio_pool_free(r1bio, data);
 166 }
 167
 168 static void put_all_bios(conf_t *conf, r1bio_t *r1_bio)
 169 {
 170         int i;
 171
 172         for (i = 0; i < conf->raid_disks; i++) {
 173                 struct bio **bio = r1_bio->bios + i;
 174                 if (*bio && *bio != IO_BLOCKED)
 175                         bio_put(*bio);
 176                 *bio = NULL;
 177         }
 178 }
 179
 180 static inline void free_r1bio(r1bio_t *r1_bio)
 181 {
 182         conf_t *conf = mddev_to_conf(r1_bio->mddev);
 183
 184         /*
 185          * Wake up any possible resync thread that waits for the device
 186          * to go idle.
 187          */
 188         allow_barrier(conf);
 189
 190         put_all_bios(conf, r1_bio);
 191         mempool_free(r1_bio, conf->r1bio_pool);
 192 }
 193
 194 static inline void put_buf(r1bio_t *r1_bio)
 195 {
 196         conf_t *conf = mddev_to_conf(r1_bio->mddev);
 197         int i;
 198
 199         for (i=0; i<conf->raid_disks; i++) {
 200                 struct bio *bio = r1_bio->bios[i];
 201                 if (bio->bi_end_io)
 202                         rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
 203         }
 204
 205         mempool_free(r1_bio, conf->r1buf_pool);
 206
 207         lower_barrier(conf);
 208 }
 209
 210 static void reschedule_retry(r1bio_t *r1_bio)
 211 {
 212         unsigned long flags;
 213         mddev_t *mddev = r1_bio->mddev;
 214         conf_t *conf = mddev_to_conf(mddev);
 215
 216         spin_lock_irqsave(&conf->device_lock, flags);
 217         list_add(&r1_bio->retry_list, &conf->retry_list);
 218         conf->nr_queued ++;
 219         spin_unlock_irqrestore(&conf->device_lock, flags);
 220
 221         wake_up(&conf->wait_barrier);
 222         md_wakeup_thread(mddev->thread);
 223 }
 224
 225 /*
 226  * raid_end_bio_io() is called when we have finished servicing a mirrored
 227  * operation and are ready to return a success/failure code to the buffer
 228  * cache layer.
 229  */
 230 static void raid_end_bio_io(r1bio_t *r1_bio)
 231 {
 232         struct bio *bio = r1_bio->master_bio;
 233
 234         /* if nobody has done the final endio yet, do it now */
 235         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 236                 PRINTK(KERN_DEBUG "raid1: sync end %s on sectors %llu-%llu\n",
 237                         (bio_data_dir(bio) == WRITE) ? "write" : "read",
 238                         (unsigned long long) bio->bi_sector,
 239                         (unsigned long long) bio->bi_sector +
 240                                 (bio->bi_size >> 9) - 1);
 241
 242                 bio_endio(bio, bio->bi_size,
 243                         test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO);
 244         }
 245         free_r1bio(r1_bio);
 246 }
 247
 248 /*
 249  * Update disk head position estimator based on IRQ completion info.
 250  */
 251 static inline void update_head_pos(int disk, r1bio_t *r1_bio)
 252 {
 253         conf_t *conf = mddev_to_conf(r1_bio->mddev);
 254
 255         conf->mirrors[disk].head_position =
 256                 r1_bio->sector + (r1_bio->sectors);
 257 }
 258
 259 static int raid1_end_read_request(struct bio *bio, unsigned int bytes_done, int error)
 260 {
 261         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 262         r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
 263         int mirror;
 264         conf_t *conf = mddev_to_conf(r1_bio->mddev);
 265
 266         if (bio->bi_size)
 267                 return 1;
 268
 269         mirror = r1_bio->read_disk;
 270         /*
 271          * this branch is our 'one mirror IO has finished' event handler:
 272          */
 273         update_head_pos(mirror, r1_bio);
 274
 275         if (uptodate || conf->working_disks <= 1) {
 276                 /*
 277                  * Set R1BIO_Uptodate in our master bio, so that
 278                  * we will return a good error code for to the higher
 279                  * levels even if IO on some other mirrored buffer fails.
 280                  *
 281                  * The 'master' represents the composite IO operation to
 282                  * user-side. So if something waits for IO, then it will
 283                  * wait for the 'master' bio.
 284                  */
 285                 if (uptodate)
 286                         set_bit(R1BIO_Uptodate, &r1_bio->state);
 287
 288                 raid_end_bio_io(r1_bio);
 289         } else {
 290                 /*
 291                  * oops, read error:
 292                  */
 293                 char b[BDEVNAME_SIZE];
 294                 if (printk_ratelimit())
 295                         printk(KERN_ERR "raid1: %s: rescheduling sector %llu\n",
 296                                bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector);
 297                 reschedule_retry(r1_bio);
 298         }
 299
 300         rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
 301         return 0;
 302 }
 303
 304 static int raid1_end_write_request(struct bio *bio, unsigned int bytes_done, int error)
 305 {
 306         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 307         r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
 308         int mirror, behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
 309         conf_t *conf = mddev_to_conf(r1_bio->mddev);
 310
 311         if (bio->bi_size)
 312                 return 1;
 313
 314         for (mirror = 0; mirror < conf->raid_disks; mirror++)
 315                 if (r1_bio->bios[mirror] == bio)
 316                         break;
 317
 318         if (error == -ENOTSUPP && test_bit(R1BIO_Barrier, &r1_bio->state)) {
 319                 set_bit(BarriersNotsupp, &conf->mirrors[mirror].rdev->flags);
 320                 set_bit(R1BIO_BarrierRetry, &r1_bio->state);
 321                 r1_bio->mddev->barriers_work = 0;
 322         } else {
 323                 /*
 324                  * this branch is our 'one mirror IO has finished' event handler:
 325                  */
 326                 r1_bio->bios[mirror] = NULL;
 327                 if (!uptodate) {
 328                         md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
 329                         /* an I/O failed, we can't clear the bitmap */
 330                         set_bit(R1BIO_Degraded, &r1_bio->state);
 331                 } else
 332                         /*
 333                          * Set R1BIO_Uptodate in our master bio, so that
 334                          * we will return a good error code for to the higher
 335                          * levels even if IO on some other mirrored buffer fails.
 336                          *
 337                          * The 'master' represents the composite IO operation to
 338                          * user-side. So if something waits for IO, then it will
 339                          * wait for the 'master' bio.
 340                          */
 341                         set_bit(R1BIO_Uptodate, &r1_bio->state);
 342
 343                 update_head_pos(mirror, r1_bio);
 344
 345                 if (behind) {
 346                         if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags))
 347                                 atomic_dec(&r1_bio->behind_remaining);
 348
 349                         /* In behind mode, we ACK the master bio once the I/O has safely
 350                          * reached all non-writemostly disks. Setting the Returned bit
 351                          * ensures that this gets done only once -- we don't ever want to
 352                          * return -EIO here, instead we'll wait */
 353
 354                         if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
 355                             test_bit(R1BIO_Uptodate, &r1_bio->state)) {
 356                                 /* Maybe we can return now */
 357                                 if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 358                                         struct bio *mbio = r1_bio->master_bio;
 359                                         PRINTK(KERN_DEBUG "raid1: behind end write sectors %llu-%llu\n",
 360                                                (unsigned long long) mbio->bi_sector,
 361                                                (unsigned long long) mbio->bi_sector +
 362                                                (mbio->bi_size >> 9) - 1);
 363                                         bio_endio(mbio, mbio->bi_size, 0);
 364                                 }
 365                         }
 366                 }
 367         }
 368         /*
 369          *
 370          * Let's see if all mirrored write operations have finished
 371          * already.
 372          */
 373         if (atomic_dec_and_test(&r1_bio->remaining)) {
 374                 if (test_bit(R1BIO_BarrierRetry, &r1_bio->state)) {
 375                         reschedule_retry(r1_bio);
 376                         /* Don't dec_pending yet, we want to hold
 377                          * the reference over the retry
 378                          */
 379                         return 0;
 380                 }
 381                 if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
 382                         /* free extra copy of the data pages */
 383                         int i = bio->bi_vcnt;
 384                         while (i--)
 385                                 put_page(bio->bi_io_vec[i].bv_page);
 386                 }
 387                 /* clear the bitmap if all writes complete successfully */
 388                 bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
 389                                 r1_bio->sectors,
 390                                 !test_bit(R1BIO_Degraded, &r1_bio->state),
 391                                 behind);
 392                 md_write_end(r1_bio->mddev);
 393                 raid_end_bio_io(r1_bio);
 394         }
 395
 396         if (r1_bio->bios[mirror]==NULL)
 397                 bio_put(bio);
 398
 399         rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
 400         return 0;
 401 }
 402
 403
 404 /*
 405  * This routine returns the disk from which the requested read should
 406  * be done. There is a per-array 'next expected sequential IO' sector
 407  * number - if this matches on the next IO then we use the last disk.
 408  * There is also a per-disk 'last know head position' sector that is
 409  * maintained from IRQ contexts, both the normal and the resync IO
 410  * completion handlers update this position correctly. If there is no
 411  * perfect sequential match then we pick the disk whose head is closest.
 412  *
 413  * If there are 2 mirrors in the same 2 devices, performance degrades
 414  * because position is mirror, not device based.
 415  *
 416  * The rdev for the device selected will have nr_pending incremented.
 417  */
 418 static int read_balance(conf_t *conf, r1bio_t *r1_bio)
 419 {
 420         const unsigned long this_sector = r1_bio->sector;
 421         int new_disk = conf->last_used, disk = new_disk;
 422         int wonly_disk = -1;
 423         const int sectors = r1_bio->sectors;
 424         sector_t new_distance, current_distance;
 425         mdk_rdev_t *rdev;
 426
 427         rcu_read_lock();
 428         /*
 429          * Check if we can balance. We can balance on the whole
 430          * device if no resync is going on, or below the resync window.
 431          * We take the first readable disk when above the resync window.
 432          */
 433  retry:
 434         if (conf->mddev->recovery_cp < MaxSector &&
 435             (this_sector + sectors >= conf->next_resync)) {
 436                 /* Choose the first operation device, for consistancy */
 437                 new_disk = 0;
 438
 439                 for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
 440                      r1_bio->bios[new_disk] == IO_BLOCKED ||
 441                      !rdev || !test_bit(In_sync, &rdev->flags)
 442                              || test_bit(WriteMostly, &rdev->flags);
 443                      rdev = rcu_dereference(conf->mirrors[++new_disk].rdev)) {
 444
 445                         if (rdev && test_bit(In_sync, &rdev->flags) &&
 446                                 r1_bio->bios[new_disk] != IO_BLOCKED)
 447                                 wonly_disk = new_disk;
 448
 449                         if (new_disk == conf->raid_disks - 1) {
 450                                 new_disk = wonly_disk;
 451                                 break;
 452                         }
 453                 }
 454                 goto rb_out;
 455         }
 456
 457
 458         /* make sure the disk is operational */
 459         for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
 460              r1_bio->bios[new_disk] == IO_BLOCKED ||
 461              !rdev || !test_bit(In_sync, &rdev->flags) ||
 462                      test_bit(WriteMostly, &rdev->flags);
 463              rdev = rcu_dereference(conf->mirrors[new_disk].rdev)) {
 464
 465                 if (rdev && test_bit(In_sync, &rdev->flags) &&
 466                     r1_bio->bios[new_disk] != IO_BLOCKED)
 467                         wonly_disk = new_disk;
 468
 469                 if (new_disk <= 0)
 470                         new_disk = conf->raid_disks;
 471                 new_disk--;
 472                 if (new_disk == disk) {
 473                         new_disk = wonly_disk;
 474                         break;
 475                 }
 476         }
 477
 478         if (new_disk < 0)
 479                 goto rb_out;
 480
 481         disk = new_disk;
 482         /* now disk == new_disk == starting point for search */
 483
 484         /*
 485          * Don't change to another disk for sequential reads:
 486          */
 487         if (conf->next_seq_sect == this_sector)
 488                 goto rb_out;
 489         if (this_sector == conf->mirrors[new_disk].head_position)
 490                 goto rb_out;
 491
 492         current_distance = abs(this_sector - conf->mirrors[disk].head_position);
 493
 494         /* Find the disk whose head is closest */
 495
 496         do {
 497                 if (disk <= 0)
 498                         disk = conf->raid_disks;
 499                 disk--;
 500
 501                 rdev = rcu_dereference(conf->mirrors[disk].rdev);
 502
 503                 if (!rdev || r1_bio->bios[disk] == IO_BLOCKED ||
 504                     !test_bit(In_sync, &rdev->flags) ||
 505                     test_bit(WriteMostly, &rdev->flags))
 506                         continue;
 507
 508                 if (!atomic_read(&rdev->nr_pending)) {
 509                         new_disk = disk;
 510                         break;
 511                 }
 512                 new_distance = abs(this_sector - conf->mirrors[disk].head_position);
 513                 if (new_distance < current_distance) {
 514                         current_distance = new_distance;
 515                         new_disk = disk;
 516                 }
 517         } while (disk != conf->last_used);
 518
 519  rb_out:
 520
 521
 522         if (new_disk >= 0) {
 523                 rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
 524                 if (!rdev)
 525                         goto retry;
 526                 atomic_inc(&rdev->nr_pending);
 527                 if (!test_bit(In_sync, &rdev->flags)) {
 528                         /* cannot risk returning a device that failed
 529                          * before we inc'ed nr_pending
 530                          */
 531                         atomic_dec(&rdev->nr_pending);
 532                         goto retry;
 533                 }
 534                 conf->next_seq_sect = this_sector + sectors;
 535                 conf->last_used = new_disk;
 536         }
 537         rcu_read_unlock();
 538
 539         return new_disk;
 540 }
 541
 542 static void unplug_slaves(mddev_t *mddev)
 543 {
 544         conf_t *conf = mddev_to_conf(mddev);
 545         int i;
 546
 547         rcu_read_lock();
 548         for (i=0; i<mddev->raid_disks; i++) {
 549                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
 550                 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
 551                         request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
 552
 553                         atomic_inc(&rdev->nr_pending);
 554                         rcu_read_unlock();
 555
 556                         if (r_queue->unplug_fn)
 557                                 r_queue->unplug_fn(r_queue);
 558
 559                         rdev_dec_pending(rdev, mddev);
 560                         rcu_read_lock();
 561                 }
 562         }
 563         rcu_read_unlock();
 564 }
 565
 566 static void raid1_unplug(request_queue_t *q)
 567 {
 568         mddev_t *mddev = q->queuedata;
 569
 570         unplug_slaves(mddev);
 571         md_wakeup_thread(mddev->thread);
 572 }
 573
 574 static int raid1_issue_flush(request_queue_t *q, struct gendisk *disk,
 575                              sector_t *error_sector)
 576 {
 577         mddev_t *mddev = q->queuedata;
 578         conf_t *conf = mddev_to_conf(mddev);
 579         int i, ret = 0;
 580
 581         rcu_read_lock();
 582         for (i=0; i<mddev->raid_disks && ret == 0; i++) {
 583                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
 584                 if (rdev && !test_bit(Faulty, &rdev->flags)) {
 585                         struct block_device *bdev = rdev->bdev;
 586                         request_queue_t *r_queue = bdev_get_queue(bdev);
 587
 588                         if (!r_queue->issue_flush_fn)
 589                                 ret = -EOPNOTSUPP;
 590                         else {
 591                                 atomic_inc(&rdev->nr_pending);
 592                                 rcu_read_unlock();
 593                                 ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
 594                                                               error_sector);
 595                                 rdev_dec_pending(rdev, mddev);
 596                                 rcu_read_lock();
 597                         }
 598                 }
 599         }
 600         rcu_read_unlock();
 601         return ret;
 602 }
 603
 604 /* Barriers....
 605  * Sometimes we need to suspend IO while we do something else,
 606  * either some resync/recovery, or reconfigure the array.
 607  * To do this we raise a 'barrier'.
 608  * The 'barrier' is a counter that can be raised multiple times
 609  * to count how many activities are happening which preclude
 610  * normal IO.
 611  * We can only raise the barrier if there is no pending IO.
 612  * i.e. if nr_pending == 0.
 613  * We choose only to raise the barrier if no-one is waiting for the
 614  * barrier to go down.  This means that as soon as an IO request
 615  * is ready, no other operations which require a barrier will start
 616  * until the IO request has had a chance.
 617  *
 618  * So: regular IO calls 'wait_barrier'.  When that returns there
 619  *    is no backgroup IO happening,  It must arrange to call
 620  *    allow_barrier when it has finished its IO.
 621  * backgroup IO calls must call raise_barrier.  Once that returns
 622  *    there is no normal IO happeing.  It must arrange to call
 623  *    lower_barrier when the particular background IO completes.
 624  */
 625 #define RESYNC_DEPTH 32
 626
 627 static void raise_barrier(conf_t *conf)
 628 {
 629         spin_lock_irq(&conf->resync_lock);
 630
 631         /* Wait until no block IO is waiting */
 632         wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
 633                             conf->resync_lock,
 634                             raid1_unplug(conf->mddev->queue));
 635
 636         /* block any new IO from starting */
 637         conf->barrier++;
 638
 639         /* No wait for all pending IO to complete */
 640         wait_event_lock_irq(conf->wait_barrier,
 641                             !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
 642                             conf->resync_lock,
 643                             raid1_unplug(conf->mddev->queue));
 644
 645         spin_unlock_irq(&conf->resync_lock);
 646 }
 647
 648 static void lower_barrier(conf_t *conf)
 649 {
 650         unsigned long flags;
 651         spin_lock_irqsave(&conf->resync_lock, flags);
 652         conf->barrier--;
 653         spin_unlock_irqrestore(&conf->resync_lock, flags);
 654         wake_up(&conf->wait_barrier);
 655 }
 656
 657 static void wait_barrier(conf_t *conf)
 658 {
 659         spin_lock_irq(&conf->resync_lock);
 660         if (conf->barrier) {
 661                 conf->nr_waiting++;
 662                 wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
 663                                     conf->resync_lock,
 664                                     raid1_unplug(conf->mddev->queue));
 665                 conf->nr_waiting--;
 666         }
 667         conf->nr_pending++;
 668         spin_unlock_irq(&conf->resync_lock);
 669 }
 670
 671 static void allow_barrier(conf_t *conf)
 672 {
 673         unsigned long flags;
 674         spin_lock_irqsave(&conf->resync_lock, flags);
 675         conf->nr_pending--;
 676         spin_unlock_irqrestore(&conf->resync_lock, flags);
 677         wake_up(&conf->wait_barrier);
 678 }
 679
 680 static void freeze_array(conf_t *conf)
 681 {
 682         /* stop syncio and normal IO and wait for everything to
 683          * go quite.
 684          * We increment barrier and nr_waiting, and then
 685          * wait until barrier+nr_pending match nr_queued+2
 686          */
 687         spin_lock_irq(&conf->resync_lock);
 688         conf->barrier++;
 689         conf->nr_waiting++;
 690         wait_event_lock_irq(conf->wait_barrier,
 691                             conf->barrier+conf->nr_pending == conf->nr_queued+2,
 692                             conf->resync_lock,
 693                             raid1_unplug(conf->mddev->queue));
 694         spin_unlock_irq(&conf->resync_lock);
 695 }
 696 static void unfreeze_array(conf_t *conf)
 697 {
 698         /* reverse the effect of the freeze */
 699         spin_lock_irq(&conf->resync_lock);
 700         conf->barrier--;
 701         conf->nr_waiting--;
 702         wake_up(&conf->wait_barrier);
 703         spin_unlock_irq(&conf->resync_lock);
 704 }
 705
 706
 707 /* duplicate the data pages for behind I/O */
 708 static struct page **alloc_behind_pages(struct bio *bio)
 709 {
 710         int i;
 711         struct bio_vec *bvec;
 712         struct page **pages = kzalloc(bio->bi_vcnt * sizeof(struct page *),
 713                                         GFP_NOIO);
 714         if (unlikely(!pages))
 715                 goto do_sync_io;
 716
 717         bio_for_each_segment(bvec, bio, i) {
 718                 pages[i] = alloc_page(GFP_NOIO);
 719                 if (unlikely(!pages[i]))
 720                         goto do_sync_io;
 721                 memcpy(kmap(pages[i]) + bvec->bv_offset,
 722                         kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
 723                 kunmap(pages[i]);
 724                 kunmap(bvec->bv_page);
 725         }
 726
 727         return pages;
 728
 729 do_sync_io:
 730         if (pages)
 731                 for (i = 0; i < bio->bi_vcnt && pages[i]; i++)
 732                         put_page(pages[i]);
 733         kfree(pages);
 734         PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
 735         return NULL;
 736 }
 737
 738 static int make_request(request_queue_t *q, struct bio * bio)
 739 {
 740         mddev_t *mddev = q->queuedata;
 741         conf_t *conf = mddev_to_conf(mddev);
 742         mirror_info_t *mirror;
 743         r1bio_t *r1_bio;
 744         struct bio *read_bio;
 745         int i, targets = 0, disks;
 746         mdk_rdev_t *rdev;
 747         struct bitmap *bitmap = mddev->bitmap;
 748         unsigned long flags;
 749         struct bio_list bl;
 750         struct page **behind_pages = NULL;
 751         const int rw = bio_data_dir(bio);
 752         int do_barriers;
 753
 754         if (unlikely(!mddev->barriers_work && bio_barrier(bio))) {
 755                 bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
 756                 return 0;
 757         }
 758
 759         /*
 760          * Register the new request and wait if the reconstruction
 761          * thread has put up a bar for new requests.
 762          * Continue immediately if no resync is active currently.
 763          */
 764         md_write_start(mddev, bio); /* wait on superblock update early */
 765
 766         wait_barrier(conf);
 767
 768         disk_stat_inc(mddev->gendisk, ios[rw]);
 769         disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
 770
 771         /*
 772          * make_request() can abort the operation when READA is being
 773          * used and no empty request is available.
 774          *
 775          */
 776         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
 777
 778         r1_bio->master_bio = bio;
 779         r1_bio->sectors = bio->bi_size >> 9;
 780         r1_bio->state = 0;
 781         r1_bio->mddev = mddev;
 782         r1_bio->sector = bio->bi_sector;
 783
 784         if (rw == READ) {
 785                 /*
 786                  * read balancing logic:
 787                  */
 788                 int rdisk = read_balance(conf, r1_bio);
 789
 790                 if (rdisk < 0) {
 791                         /* couldn't find anywhere to read from */
 792                         raid_end_bio_io(r1_bio);
 793                         return 0;
 794                 }
 795                 mirror = conf->mirrors + rdisk;
 796
 797                 r1_bio->read_disk = rdisk;
 798
 799                 read_bio = bio_clone(bio, GFP_NOIO);
 800
 801                 r1_bio->bios[rdisk] = read_bio;
 802
 803                 read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
 804                 read_bio->bi_bdev = mirror->rdev->bdev;
 805                 read_bio->bi_end_io = raid1_end_read_request;
 806                 read_bio->bi_rw = READ;
 807                 read_bio->bi_private = r1_bio;
 808
 809                 generic_make_request(read_bio);
 810                 return 0;
 811         }
 812
 813         /*
 814          * WRITE:
 815          */
 816         /* first select target devices under spinlock and
 817          * inc refcount on their rdev.  Record them by setting
 818          * bios[x] to bio
 819          */
 820         disks = conf->raid_disks;
 821 #if 0
 822         { static int first=1;
 823         if (first) printk("First Write sector %llu disks %d\n",
 824                           (unsigned long long)r1_bio->sector, disks);
 825         first = 0;
 826         }
 827 #endif
 828         rcu_read_lock();
 829         for (i = 0;  i < disks; i++) {
 830                 if ((rdev=rcu_dereference(conf->mirrors[i].rdev)) != NULL &&
 831                     !test_bit(Faulty, &rdev->flags)) {
 832                         atomic_inc(&rdev->nr_pending);
 833                         if (test_bit(Faulty, &rdev->flags)) {
 834                                 atomic_dec(&rdev->nr_pending);
 835                                 r1_bio->bios[i] = NULL;
 836                         } else
 837                                 r1_bio->bios[i] = bio;
 838                         targets++;
 839                 } else
 840                         r1_bio->bios[i] = NULL;
 841         }
 842         rcu_read_unlock();
 843
 844         BUG_ON(targets == 0); /* we never fail the last device */
 845
 846         if (targets < conf->raid_disks) {
 847                 /* array is degraded, we will not clear the bitmap
 848                  * on I/O completion (see raid1_end_write_request) */
 849                 set_bit(R1BIO_Degraded, &r1_bio->state);
 850         }
 851
 852         /* do behind I/O ? */
 853         if (bitmap &&
 854             atomic_read(&bitmap->behind_writes) < bitmap->max_write_behind &&
 855             (behind_pages = alloc_behind_pages(bio)) != NULL)
 856                 set_bit(R1BIO_BehindIO, &r1_bio->state);
 857
 858         atomic_set(&r1_bio->remaining, 0);
 859         atomic_set(&r1_bio->behind_remaining, 0);
 860
 861         do_barriers = bio->bi_rw & BIO_RW_BARRIER;
 862         if (do_barriers)
 863                 set_bit(R1BIO_Barrier, &r1_bio->state);
 864
 865         bio_list_init(&bl);
 866         for (i = 0; i < disks; i++) {
 867                 struct bio *mbio;
 868                 if (!r1_bio->bios[i])
 869                         continue;
 870
 871                 mbio = bio_clone(bio, GFP_NOIO);
 872                 r1_bio->bios[i] = mbio;
 873
 874                 mbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset;
 875                 mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
 876                 mbio->bi_end_io = raid1_end_write_request;
 877                 mbio->bi_rw = WRITE | do_barriers;
 878                 mbio->bi_private = r1_bio;
 879
 880                 if (behind_pages) {
 881                         struct bio_vec *bvec;
 882                         int j;
 883
 884                         /* Yes, I really want the '__' version so that
 885                          * we clear any unused pointer in the io_vec, rather
 886                          * than leave them unchanged.  This is important
 887                          * because when we come to free the pages, we won't
 888                          * know the originial bi_idx, so we just free
 889                          * them all
 890                          */
 891                         __bio_for_each_segment(bvec, mbio, j, 0)
 892                                 bvec->bv_page = behind_pages[j];
 893                         if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
 894                                 atomic_inc(&r1_bio->behind_remaining);
 895                 }
 896
 897                 atomic_inc(&r1_bio->remaining);
 898
 899                 bio_list_add(&bl, mbio);
 900         }
 901         kfree(behind_pages); /* the behind pages are attached to the bios now */
 902
 903         bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors,
 904                                 test_bit(R1BIO_BehindIO, &r1_bio->state));
 905         spin_lock_irqsave(&conf->device_lock, flags);
 906         bio_list_merge(&conf->pending_bio_list, &bl);
 907         bio_list_init(&bl);
 908
 909         blk_plug_device(mddev->queue);
 910         spin_unlock_irqrestore(&conf->device_lock, flags);
 911
 912 #if 0
 913         while ((bio = bio_list_pop(&bl)) != NULL)
 914                 generic_make_request(bio);
 915 #endif
 916
 917         return 0;
 918 }
 919
 920 static void status(struct seq_file *seq, mddev_t *mddev)
 921 {
 922         conf_t *conf = mddev_to_conf(mddev);
 923         int i;
 924
 925         seq_printf(seq, " [%d/%d] [", conf->raid_disks,
 926                                                 conf->working_disks);
 927         for (i = 0; i < conf->raid_disks; i++)
 928                 seq_printf(seq, "%s",
 929                               conf->mirrors[i].rdev &&
 930                               test_bit(In_sync, &conf->mirrors[i].rdev->flags) ? "U" : "_");
 931         seq_printf(seq, "]");
 932 }
 933
 934
 935 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
 936 {
 937         char b[BDEVNAME_SIZE];
 938         conf_t *conf = mddev_to_conf(mddev);
 939
 940         /*
 941          * If it is not operational, then we have already marked it as dead
 942          * else if it is the last working disks, ignore the error, let the
 943          * next level up know.
 944          * else mark the drive as failed
 945          */
 946         if (test_bit(In_sync, &rdev->flags)
 947             && conf->working_disks == 1)
 948                 /*
 949                  * Don't fail the drive, act as though we were just a
 950                  * normal single drive
 951                  */
 952                 return;
 953         if (test_bit(In_sync, &rdev->flags)) {
 954                 mddev->degraded++;
 955                 conf->working_disks--;
 956                 /*
 957                  * if recovery is running, make sure it aborts.
 958                  */
 959                 set_bit(MD_RECOVERY_ERR, &mddev->recovery);
 960         }
 961         clear_bit(In_sync, &rdev->flags);
 962         set_bit(Faulty, &rdev->flags);
 963         mddev->sb_dirty = 1;
 964         printk(KERN_ALERT "raid1: Disk failure on %s, disabling device. \n"
 965                 "       Operation continuing on %d devices\n",
 966                 bdevname(rdev->bdev,b), conf->working_disks);
 967 }
 968
 969 static void print_conf(conf_t *conf)
 970 {
 971         int i;
 972         mirror_info_t *tmp;
 973
 974         printk("RAID1 conf printout:\n");
 975         if (!conf) {
 976                 printk("(!conf)\n");
 977                 return;
 978         }
 979         printk(" --- wd:%d rd:%d\n", conf->working_disks,
 980                 conf->raid_disks);
 981
 982         for (i = 0; i < conf->raid_disks; i++) {
 983                 char b[BDEVNAME_SIZE];
 984                 tmp = conf->mirrors + i;
 985                 if (tmp->rdev)
 986                         printk(" disk %d, wo:%d, o:%d, dev:%s\n",
 987                                 i, !test_bit(In_sync, &tmp->rdev->flags), !test_bit(Faulty, &tmp->rdev->flags),
 988                                 bdevname(tmp->rdev->bdev,b));
 989         }
 990 }
 991
 992 static void close_sync(conf_t *conf)
 993 {
 994         wait_barrier(conf);
 995         allow_barrier(conf);
 996
 997         mempool_destroy(conf->r1buf_pool);
 998         conf->r1buf_pool = NULL;
 999 }
1000
1001 static int raid1_spare_active(mddev_t *mddev)
1002 {
1003         int i;
1004         conf_t *conf = mddev->private;
1005         mirror_info_t *tmp;
1006
1007         /*
1008          * Find all failed disks within the RAID1 configuration
1009          * and mark them readable
1010          */
1011         for (i = 0; i < conf->raid_disks; i++) {
1012                 tmp = conf->mirrors + i;
1013                 if (tmp->rdev
1014                     && !test_bit(Faulty, &tmp->rdev->flags)
1015                     && !test_bit(In_sync, &tmp->rdev->flags)) {
1016                         conf->working_disks++;
1017                         mddev->degraded--;
1018                         set_bit(In_sync, &tmp->rdev->flags);
1019                 }
1020         }
1021
1022         print_conf(conf);
1023         return 0;
1024 }
1025
1026
1027 static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
1028 {
1029         conf_t *conf = mddev->private;
1030         int found = 0;
1031         int mirror = 0;
1032         mirror_info_t *p;
1033
1034         for (mirror=0; mirror < mddev->raid_disks; mirror++)
1035                 if ( !(p=conf->mirrors+mirror)->rdev) {
1036
1037                         blk_queue_stack_limits(mddev->queue,
1038                                                rdev->bdev->bd_disk->queue);
1039                         /* as we don't honour merge_bvec_fn, we must never risk
1040                          * violating it, so limit ->max_sector to one PAGE, as
1041                          * a one page request is never in violation.
1042                          */
1043                         if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
1044                             mddev->queue->max_sectors > (PAGE_SIZE>>9))
1045                                 blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
1046
1047                         p->head_position = 0;
1048                         rdev->raid_disk = mirror;
1049                         found = 1;
1050                         /* As all devices are equivalent, we don't need a full recovery
1051                          * if this was recently any drive of the array
1052                          */
1053                         if (rdev->saved_raid_disk < 0)
1054                                 conf->fullsync = 1;
1055                         rcu_assign_pointer(p->rdev, rdev);
1056                         break;
1057                 }
1058
1059         print_conf(conf);
1060         return found;
1061 }
1062
1063 static int raid1_remove_disk(mddev_t *mddev, int number)
1064 {
1065         conf_t *conf = mddev->private;
1066         int err = 0;
1067         mdk_rdev_t *rdev;
1068         mirror_info_t *p = conf->mirrors+ number;
1069
1070         print_conf(conf);
1071         rdev = p->rdev;
1072         if (rdev) {
1073                 if (test_bit(In_sync, &rdev->flags) ||
1074                     atomic_read(&rdev->nr_pending)) {
1075                         err = -EBUSY;
1076                         goto abort;
1077                 }
1078                 p->rdev = NULL;
1079                 synchronize_rcu();
1080                 if (atomic_read(&rdev->nr_pending)) {
1081                         /* lost the race, try later */
1082                         err = -EBUSY;
1083                         p->rdev = rdev;
1084                 }
1085         }
1086 abort:
1087
1088         print_conf(conf);
1089         return err;
1090 }
1091
1092
1093 static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error)
1094 {
1095         r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
1096         int i;
1097
1098         if (bio->bi_size)
1099                 return 1;
1100
1101         for (i=r1_bio->mddev->raid_disks; i--; )
1102                 if (r1_bio->bios[i] == bio)
1103                         break;
1104         BUG_ON(i < 0);
1105         update_head_pos(i, r1_bio);
1106         /*
1107          * we have read a block, now it needs to be re-written,
1108          * or re-read if the read failed.
1109          * We don't do much here, just schedule handling by raid1d
1110          */
1111         if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1112                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1113
1114         if (atomic_dec_and_test(&r1_bio->remaining))
1115                 reschedule_retry(r1_bio);
1116         return 0;
1117 }
1118
1119 static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error)
1120 {
1121         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1122         r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
1123         mddev_t *mddev = r1_bio->mddev;
1124         conf_t *conf = mddev_to_conf(mddev);
1125         int i;
1126         int mirror=0;
1127
1128         if (bio->bi_size)
1129                 return 1;
1130
1131         for (i = 0; i < conf->raid_disks; i++)
1132                 if (r1_bio->bios[i] == bio) {
1133                         mirror = i;
1134                         break;
1135                 }
1136         if (!uptodate)
1137                 md_error(mddev, conf->mirrors[mirror].rdev);
1138
1139         update_head_pos(mirror, r1_bio);
1140
1141         if (atomic_dec_and_test(&r1_bio->remaining)) {
1142                 md_done_sync(mddev, r1_bio->sectors, uptodate);
1143                 put_buf(r1_bio);
1144         }
1145         return 0;
1146 }
1147
1148 static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
1149 {
1150         conf_t *conf = mddev_to_conf(mddev);
1151         int i;
1152         int disks = conf->raid_disks;
1153         struct bio *bio, *wbio;
1154
1155         bio = r1_bio->bios[r1_bio->read_disk];
1156
1157
1158         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1159                 /* We have read all readable devices.  If we haven't
1160                  * got the block, then there is no hope left.
1161                  * If we have, then we want to do a comparison
1162                  * and skip the write if everything is the same.
1163                  * If any blocks failed to read, then we need to
1164                  * attempt an over-write
1165                  */
1166                 int primary;
1167                 if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1168                         for (i=0; i<mddev->raid_disks; i++)
1169                                 if (r1_bio->bios[i]->bi_end_io == end_sync_read)
1170                                         md_error(mddev, conf->mirrors[i].rdev);
1171
1172                         md_done_sync(mddev, r1_bio->sectors, 1);
1173                         put_buf(r1_bio);
1174                         return;
1175                 }
1176                 for (primary=0; primary<mddev->raid_disks; primary++)
1177                         if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1178                             test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
1179                                 r1_bio->bios[primary]->bi_end_io = NULL;
1180                                 break;
1181                         }
1182                 r1_bio->read_disk = primary;
1183                 for (i=0; i<mddev->raid_disks; i++)
1184                         if (r1_bio->bios[i]->bi_end_io == end_sync_read &&
1185                             test_bit(BIO_UPTODATE, &r1_bio->bios[i]->bi_flags)) {
1186                                 int j;
1187                                 int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
1188                                 struct bio *pbio = r1_bio->bios[primary];
1189                                 struct bio *sbio = r1_bio->bios[i];
1190                                 for (j = vcnt; j-- ; )
1191                                         if (memcmp(page_address(pbio->bi_io_vec[j].bv_page),
1192                                                    page_address(sbio->bi_io_vec[j].bv_page),
1193                                                    PAGE_SIZE))
1194                                                 break;
1195                                 if (j >= 0)
1196                                         mddev->resync_mismatches += r1_bio->sectors;
1197                                 if (j < 0 || test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
1198                                         sbio->bi_end_io = NULL;
1199                                 else {
1200                                         /* fixup the bio for reuse */
1201                                         sbio->bi_vcnt = vcnt;
1202                                         sbio->bi_size = r1_bio->sectors << 9;
1203                                         sbio->bi_idx = 0;
1204                                         sbio->bi_phys_segments = 0;
1205                                         sbio->bi_hw_segments = 0;
1206                                         sbio->bi_hw_front_size = 0;
1207                                         sbio->bi_hw_back_size = 0;
1208                                         sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1209                                         sbio->bi_flags |= 1 << BIO_UPTODATE;
1210                                         sbio->bi_next = NULL;
1211                                         sbio->bi_sector = r1_bio->sector +
1212                                                 conf->mirrors[i].rdev->data_offset;
1213                                         sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1214                                 }
1215                         }
1216         }
1217         if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1218                 /* ouch - failed to read all of that.
1219                  * Try some synchronous reads of other devices to get
1220                  * good data, much like with normal read errors.  Only
1221                  * read into the pages we already have so they we don't
1222                  * need to re-issue the read request.
1223                  * We don't need to freeze the array, because being in an
1224                  * active sync request, there is no normal IO, and
1225                  * no overlapping syncs.
1226                  */
1227                 sector_t sect = r1_bio->sector;
1228                 int sectors = r1_bio->sectors;
1229                 int idx = 0;
1230
1231                 while(sectors) {
1232                         int s = sectors;
1233                         int d = r1_bio->read_disk;
1234                         int success = 0;
1235                         mdk_rdev_t *rdev;
1236
1237                         if (s > (PAGE_SIZE>>9))
1238                                 s = PAGE_SIZE >> 9;
1239                         do {
1240                                 if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1241                                         rdev = conf->mirrors[d].rdev;
1242                                         if (sync_page_io(rdev->bdev,
1243                                                          sect + rdev->data_offset,
1244                                                          s<<9,
1245                                                          bio->bi_io_vec[idx].bv_page,
1246                                                          READ)) {
1247                                                 success = 1;
1248                                                 break;
1249                                         }
1250                                 }
1251                                 d++;
1252                                 if (d == conf->raid_disks)
1253                                         d = 0;
1254                         } while (!success && d != r1_bio->read_disk);
1255
1256                         if (success) {
1257                                 /* write it back and re-read */
1258                                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1259                                 while (d != r1_bio->read_disk) {
1260                                         if (d == 0)
1261                                                 d = conf->raid_disks;
1262                                         d--;
1263                                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1264                                                 continue;
1265                                         rdev = conf->mirrors[d].rdev;
1266                                         if (sync_page_io(rdev->bdev,
1267                                                          sect + rdev->data_offset,
1268                                                          s<<9,
1269                                                          bio->bi_io_vec[idx].bv_page,
1270                                                          WRITE) == 0 ||
1271                                             sync_page_io(rdev->bdev,
1272                                                          sect + rdev->data_offset,
1273                                                          s<<9,
1274                                                          bio->bi_io_vec[idx].bv_page,
1275                                                          READ) == 0) {
1276                                                 md_error(mddev, rdev);
1277                                         }
1278                                 }
1279                         } else {
1280                                 char b[BDEVNAME_SIZE];
1281                                 /* Cannot read from anywhere, array is toast */
1282                                 md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
1283                                 printk(KERN_ALERT "raid1: %s: unrecoverable I/O read error"
1284                                        " for block %llu\n",
1285                                        bdevname(bio->bi_bdev,b),
1286                                        (unsigned long long)r1_bio->sector);
1287                                 md_done_sync(mddev, r1_bio->sectors, 0);
1288                                 put_buf(r1_bio);
1289                                 return;
1290                         }
1291                         sectors -= s;
1292                         sect += s;
1293                         idx ++;
1294                 }
1295         }
1296
1297         /*
1298          * schedule writes
1299          */
1300         atomic_set(&r1_bio->remaining, 1);
1301         for (i = 0; i < disks ; i++) {
1302                 wbio = r1_bio->bios[i];
1303                 if (wbio->bi_end_io == NULL ||
1304                     (wbio->bi_end_io == end_sync_read &&
1305                      (i == r1_bio->read_disk ||
1306                       !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
1307                         continue;
1308
1309                 wbio->bi_rw = WRITE;
1310                 wbio->bi_end_io = end_sync_write;
1311                 atomic_inc(&r1_bio->remaining);
1312                 md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1313
1314                 generic_make_request(wbio);
1315         }
1316
1317         if (atomic_dec_and_test(&r1_bio->remaining)) {
1318                 /* if we're here, all write(s) have completed, so clean up */
1319                 md_done_sync(mddev, r1_bio->sectors, 1);
1320                 put_buf(r1_bio);
1321         }
1322 }
1323
1324 /*
1325  * This is a kernel thread which:
1326  *
1327  *      1.      Retries failed read operations on working mirrors.
1328  *      2.      Updates the raid superblock when problems encounter.
1329  *      3.      Performs writes following reads for array syncronising.
1330  */
1331
1332 static void raid1d(mddev_t *mddev)
1333 {
1334         r1bio_t *r1_bio;
1335         struct bio *bio;
1336         unsigned long flags;
1337         conf_t *conf = mddev_to_conf(mddev);
1338         struct list_head *head = &conf->retry_list;
1339         int unplug=0;
1340         mdk_rdev_t *rdev;
1341
1342         md_check_recovery(mddev);
1343
1344         for (;;) {
1345                 char b[BDEVNAME_SIZE];
1346                 spin_lock_irqsave(&conf->device_lock, flags);
1347
1348                 if (conf->pending_bio_list.head) {
1349                         bio = bio_list_get(&conf->pending_bio_list);
1350                         blk_remove_plug(mddev->queue);
1351                         spin_unlock_irqrestore(&conf->device_lock, flags);
1352                         /* flush any pending bitmap writes to disk before proceeding w/ I/O */
1353                         if (bitmap_unplug(mddev->bitmap) != 0)
1354                                 printk("%s: bitmap file write failed!\n", mdname(mddev));
1355
1356                         while (bio) { /* submit pending writes */
1357                                 struct bio *next = bio->bi_next;
1358                                 bio->bi_next = NULL;
1359                                 generic_make_request(bio);
1360                                 bio = next;
1361                         }
1362                         unplug = 1;
1363
1364                         continue;
1365                 }
1366
1367                 if (list_empty(head))
1368                         break;
1369                 r1_bio = list_entry(head->prev, r1bio_t, retry_list);
1370                 list_del(head->prev);
1371                 conf->nr_queued--;
1372                 spin_unlock_irqrestore(&conf->device_lock, flags);
1373
1374                 mddev = r1_bio->mddev;
1375                 conf = mddev_to_conf(mddev);
1376                 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
1377                         sync_request_write(mddev, r1_bio);
1378                         unplug = 1;
1379                 } else if (test_bit(R1BIO_BarrierRetry, &r1_bio->state)) {
1380                         /* some requests in the r1bio were BIO_RW_BARRIER
1381                          * requests which failed with -ENOTSUPP.  Hohumm..
1382                          * Better resubmit without the barrier.
1383                          * We know which devices to resubmit for, because
1384                          * all others have had their bios[] entry cleared.
1385                          */
1386                         int i;
1387                         clear_bit(R1BIO_BarrierRetry, &r1_bio->state);
1388                         clear_bit(R1BIO_Barrier, &r1_bio->state);
1389                         for (i=0; i < conf->raid_disks; i++)
1390                                 if (r1_bio->bios[i]) {
1391                                         struct bio_vec *bvec;
1392                                         int j;
1393
1394                                         bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
1395                                         /* copy pages from the failed bio, as
1396                                          * this might be a write-behind device */
1397                                         __bio_for_each_segment(bvec, bio, j, 0)
1398                                                 bvec->bv_page = bio_iovec_idx(r1_bio->bios[i], j)->bv_page;
1399                                         bio_put(r1_bio->bios[i]);
1400                                         bio->bi_sector = r1_bio->sector +
1401                                                 conf->mirrors[i].rdev->data_offset;
1402                                         bio->bi_bdev = conf->mirrors[i].rdev->bdev;
1403                                         bio->bi_end_io = raid1_end_write_request;
1404                                         bio->bi_rw = WRITE;
1405                                         bio->bi_private = r1_bio;
1406                                         r1_bio->bios[i] = bio;
1407                                         generic_make_request(bio);
1408                                 }
1409                 } else {
1410                         int disk;
1411
1412                         /* we got a read error. Maybe the drive is bad.  Maybe just
1413                          * the block and we can fix it.
1414                          * We freeze all other IO, and try reading the block from
1415                          * other devices.  When we find one, we re-write
1416                          * and check it that fixes the read error.
1417                          * This is all done synchronously while the array is
1418                          * frozen
1419                          */
1420                         sector_t sect = r1_bio->sector;
1421                         int sectors = r1_bio->sectors;
1422                         freeze_array(conf);
1423                         if (mddev->ro == 0) while(sectors) {
1424                                 int s = sectors;
1425                                 int d = r1_bio->read_disk;
1426                                 int success = 0;
1427
1428                                 if (s > (PAGE_SIZE>>9))
1429                                         s = PAGE_SIZE >> 9;
1430
1431                                 do {
1432                                         rdev = conf->mirrors[d].rdev;
1433                                         if (rdev &&
1434                                             test_bit(In_sync, &rdev->flags) &&
1435                                             sync_page_io(rdev->bdev,
1436                                                          sect + rdev->data_offset,
1437                                                          s<<9,
1438                                                          conf->tmppage, READ))
1439                                                 success = 1;
1440                                         else {
1441                                                 d++;
1442                                                 if (d == conf->raid_disks)
1443                                                         d = 0;
1444                                         }
1445                                 } while (!success && d != r1_bio->read_disk);
1446
1447                                 if (success) {
1448                                         /* write it back and re-read */
1449                                         while (d != r1_bio->read_disk) {
1450                                                 if (d==0)
1451                                                         d = conf->raid_disks;
1452                                                 d--;
1453                                                 rdev = conf->mirrors[d].rdev;
1454                                                 if (rdev &&
1455                                                     test_bit(In_sync, &rdev->flags)) {
1456                                                         if (sync_page_io(rdev->bdev,
1457                                                                          sect + rdev->data_offset,
1458                                                                          s<<9, conf->tmppage, WRITE) == 0 ||
1459                                                             sync_page_io(rdev->bdev,
1460                                                                          sect + rdev->data_offset,
1461                                                                          s<<9, conf->tmppage, READ) == 0) {
1462                                                                 /* Well, this device is dead */
1463                                                                 md_error(mddev, rdev);
1464                                                         }
1465                                                 }
1466                                         }
1467                                 } else {
1468                                         /* Cannot read from anywhere -- bye bye array */
1469                                         md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
1470                                         break;
1471                                 }
1472                                 sectors -= s;
1473                                 sect += s;
1474                         }
1475
1476                         unfreeze_array(conf);
1477
1478                         bio = r1_bio->bios[r1_bio->read_disk];
1479                         if ((disk=read_balance(conf, r1_bio)) == -1) {
1480                                 printk(KERN_ALERT "raid1: %s: unrecoverable I/O"
1481                                        " read error for block %llu\n",
1482                                        bdevname(bio->bi_bdev,b),
1483                                        (unsigned long long)r1_bio->sector);
1484                                 raid_end_bio_io(r1_bio);
1485                         } else {
1486                                 r1_bio->bios[r1_bio->read_disk] =
1487                                         mddev->ro ? IO_BLOCKED : NULL;
1488                                 r1_bio->read_disk = disk;
1489                                 bio_put(bio);
1490                                 bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
1491                                 r1_bio->bios[r1_bio->read_disk] = bio;
1492                                 rdev = conf->mirrors[disk].rdev;
1493                                 if (printk_ratelimit())
1494                                         printk(KERN_ERR "raid1: %s: redirecting sector %llu to"
1495                                                " another mirror\n",
1496                                                bdevname(rdev->bdev,b),
1497                                                (unsigned long long)r1_bio->sector);
1498                                 bio->bi_sector = r1_bio->sector + rdev->data_offset;
1499                                 bio->bi_bdev = rdev->bdev;
1500                                 bio->bi_end_io = raid1_end_read_request;
1501                                 bio->bi_rw = READ;
1502                                 bio->bi_private = r1_bio;
1503                                 unplug = 1;
1504                                 generic_make_request(bio);
1505                         }
1506                 }
1507         }
1508         spin_unlock_irqrestore(&conf->device_lock, flags);
1509         if (unplug)
1510                 unplug_slaves(mddev);
1511 }
1512
1513
1514 static int init_resync(conf_t *conf)
1515 {
1516         int buffs;
1517
1518         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1519         if (conf->r1buf_pool)
1520                 BUG();
1521         conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
1522                                           conf->poolinfo);
1523         if (!conf->r1buf_pool)
1524                 return -ENOMEM;
1525         conf->next_resync = 0;
1526         return 0;
1527 }
1528
1529 /*
1530  * perform a "sync" on one "block"
1531  *
1532  * We need to make sure that no normal I/O request - particularly write
1533  * requests - conflict with active sync requests.
1534  *
1535  * This is achieved by tracking pending requests and a 'barrier' concept
1536  * that can be installed to exclude normal IO requests.
1537  */
1538
1539 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
1540 {
1541         conf_t *conf = mddev_to_conf(mddev);
1542         r1bio_t *r1_bio;
1543         struct bio *bio;
1544         sector_t max_sector, nr_sectors;
1545         int disk = -1;
1546         int i;
1547         int wonly = -1;
1548         int write_targets = 0, read_targets = 0;
1549         int sync_blocks;
1550         int still_degraded = 0;
1551
1552         if (!conf->r1buf_pool)
1553         {
1554 /*
1555                 printk("sync start - bitmap %p\n", mddev->bitmap);
1556 */
1557                 if (init_resync(conf))
1558                         return 0;
1559         }
1560
1561         max_sector = mddev->size << 1;
1562         if (sector_nr >= max_sector) {
1563                 /* If we aborted, we need to abort the
1564                  * sync on the 'current' bitmap chunk (there will
1565                  * only be one in raid1 resync.
1566                  * We can find the current addess in mddev->curr_resync
1567                  */
1568                 if (mddev->curr_resync < max_sector) /* aborted */
1569                         bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1570                                                 &sync_blocks, 1);
1571                 else /* completed sync */
1572                         conf->fullsync = 0;
1573
1574                 bitmap_close_sync(mddev->bitmap);
1575                 close_sync(conf);
1576                 return 0;
1577         }
1578
1579         /* before building a request, check if we can skip these blocks..
1580          * This call the bitmap_start_sync doesn't actually record anything
1581          */
1582         if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
1583             !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1584                 /* We can skip this block, and probably several more */
1585                 *skipped = 1;
1586                 return sync_blocks;
1587         }
1588         /*
1589          * If there is non-resync activity waiting for a turn,
1590          * and resync is going fast enough,
1591          * then let it though before starting on this new sync request.
1592          */
1593         if (!go_faster && conf->nr_waiting)
1594                 msleep_interruptible(1000);
1595
1596         raise_barrier(conf);
1597
1598         conf->next_resync = sector_nr;
1599
1600         r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
1601         rcu_read_lock();
1602         /*
1603          * If we get a correctably read error during resync or recovery,
1604          * we might want to read from a different device.  So we
1605          * flag all drives that could conceivably be read from for READ,
1606          * and any others (which will be non-In_sync devices) for WRITE.
1607          * If a read fails, we try reading from something else for which READ
1608          * is OK.
1609          */
1610
1611         r1_bio->mddev = mddev;
1612         r1_bio->sector = sector_nr;
1613         r1_bio->state = 0;
1614         set_bit(R1BIO_IsSync, &r1_bio->state);
1615
1616         for (i=0; i < conf->raid_disks; i++) {
1617                 mdk_rdev_t *rdev;
1618                 bio = r1_bio->bios[i];
1619
1620                 /* take from bio_init */
1621                 bio->bi_next = NULL;
1622                 bio->bi_flags |= 1 << BIO_UPTODATE;
1623                 bio->bi_rw = 0;
1624                 bio->bi_vcnt = 0;
1625                 bio->bi_idx = 0;
1626                 bio->bi_phys_segments = 0;
1627                 bio->bi_hw_segments = 0;
1628                 bio->bi_size = 0;
1629                 bio->bi_end_io = NULL;
1630                 bio->bi_private = NULL;
1631
1632                 rdev = rcu_dereference(conf->mirrors[i].rdev);
1633                 if (rdev == NULL ||
1634                            test_bit(Faulty, &rdev->flags)) {
1635                         still_degraded = 1;
1636                         continue;
1637                 } else if (!test_bit(In_sync, &rdev->flags)) {
1638                         bio->bi_rw = WRITE;
1639                         bio->bi_end_io = end_sync_write;
1640                         write_targets ++;
1641                 } else {
1642                         /* may need to read from here */
1643                         bio->bi_rw = READ;
1644                         bio->bi_end_io = end_sync_read;
1645                         if (test_bit(WriteMostly, &rdev->flags)) {
1646                                 if (wonly < 0)
1647                                         wonly = i;
1648                         } else {
1649                                 if (disk < 0)
1650                                         disk = i;
1651                         }
1652                         read_targets++;
1653                 }
1654                 atomic_inc(&rdev->nr_pending);
1655                 bio->bi_sector = sector_nr + rdev->data_offset;
1656                 bio->bi_bdev = rdev->bdev;
1657                 bio->bi_private = r1_bio;
1658         }
1659         rcu_read_unlock();
1660         if (disk < 0)
1661                 disk = wonly;
1662         r1_bio->read_disk = disk;
1663
1664         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
1665                 /* extra read targets are also write targets */
1666                 write_targets += read_targets-1;
1667
1668         if (write_targets == 0 || read_targets == 0) {
1669                 /* There is nowhere to write, so all non-sync
1670                  * drives must be failed - so we are finished
1671                  */
1672                 sector_t rv = max_sector - sector_nr;
1673                 *skipped = 1;
1674                 put_buf(r1_bio);
1675                 return rv;
1676         }
1677
1678         nr_sectors = 0;
1679         sync_blocks = 0;
1680         do {
1681                 struct page *page;
1682                 int len = PAGE_SIZE;
1683                 if (sector_nr + (len>>9) > max_sector)
1684                         len = (max_sector - sector_nr) << 9;
1685                 if (len == 0)
1686                         break;
1687                 if (sync_blocks == 0) {
1688                         if (!bitmap_start_sync(mddev->bitmap, sector_nr,
1689                                                &sync_blocks, still_degraded) &&
1690                             !conf->fullsync &&
1691                             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1692                                 break;
1693                         if (sync_blocks < (PAGE_SIZE>>9))
1694                                 BUG();
1695                         if (len > (sync_blocks<<9))
1696                                 len = sync_blocks<<9;
1697                 }
1698
1699                 for (i=0 ; i < conf->raid_disks; i++) {
1700                         bio = r1_bio->bios[i];
1701                         if (bio->bi_end_io) {
1702                                 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
1703                                 if (bio_add_page(bio, page, len, 0) == 0) {
1704                                         /* stop here */
1705                                         bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
1706                                         while (i > 0) {
1707                                                 i--;
1708                                                 bio = r1_bio->bios[i];
1709                                                 if (bio->bi_end_io==NULL)
1710                                                         continue;
1711                                                 /* remove last page from this bio */
1712                                                 bio->bi_vcnt--;
1713                                                 bio->bi_size -= len;
1714                                                 bio->bi_flags &= ~(1<< BIO_SEG_VALID);
1715                                         }
1716                                         goto bio_full;
1717                                 }
1718                         }
1719                 }
1720                 nr_sectors += len>>9;
1721                 sector_nr += len>>9;
1722                 sync_blocks -= (len>>9);
1723         } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
1724  bio_full:
1725         r1_bio->sectors = nr_sectors;
1726
1727         /* For a user-requested sync, we read all readable devices and do a
1728          * compare
1729          */
1730         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1731                 atomic_set(&r1_bio->remaining, read_targets);
1732                 for (i=0; i<conf->raid_disks; i++) {
1733                         bio = r1_bio->bios[i];
1734                         if (bio->bi_end_io == end_sync_read) {
1735                                 md_sync_acct(conf->mirrors[i].rdev->bdev, nr_sectors);
1736                                 generic_make_request(bio);
1737                         }
1738                 }
1739         } else {
1740                 atomic_set(&r1_bio->remaining, 1);
1741                 bio = r1_bio->bios[r1_bio->read_disk];
1742                 md_sync_acct(conf->mirrors[r1_bio->read_disk].rdev->bdev,
1743                              nr_sectors);
1744                 generic_make_request(bio);
1745
1746         }
1747
1748         return nr_sectors;
1749 }
1750
1751 static int run(mddev_t *mddev)
1752 {
1753         conf_t *conf;
1754         int i, j, disk_idx;
1755         mirror_info_t *disk;
1756         mdk_rdev_t *rdev;
1757         struct list_head *tmp;
1758
1759         if (mddev->level != 1) {
1760                 printk("raid1: %s: raid level not set to mirroring (%d)\n",
1761                        mdname(mddev), mddev->level);
1762                 goto out;
1763         }
1764         /*
1765          * copy the already verified devices into our private RAID1
1766          * bookkeeping area. [whatever we allocate in run(),
1767          * should be freed in stop()]
1768          */
1769         conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
1770         mddev->private = conf;
1771         if (!conf)
1772                 goto out_no_mem;
1773
1774         conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
1775                                  GFP_KERNEL);
1776         if (!conf->mirrors)
1777                 goto out_no_mem;
1778
1779         conf->tmppage = alloc_page(GFP_KERNEL);
1780         if (!conf->tmppage)
1781                 goto out_no_mem;
1782
1783         conf->poolinfo = kmalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
1784         if (!conf->poolinfo)
1785                 goto out_no_mem;
1786         conf->poolinfo->mddev = mddev;
1787         conf->poolinfo->raid_disks = mddev->raid_disks;
1788         conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
1789                                           r1bio_pool_free,
1790                                           conf->poolinfo);
1791         if (!conf->r1bio_pool)
1792                 goto out_no_mem;
1793
1794         ITERATE_RDEV(mddev, rdev, tmp) {
1795                 disk_idx = rdev->raid_disk;
1796                 if (disk_idx >= mddev->raid_disks
1797                     || disk_idx < 0)
1798                         continue;
1799                 disk = conf->mirrors + disk_idx;
1800
1801                 disk->rdev = rdev;
1802
1803                 blk_queue_stack_limits(mddev->queue,
1804                                        rdev->bdev->bd_disk->queue);
1805                 /* as we don't honour merge_bvec_fn, we must never risk
1806                  * violating it, so limit ->max_sector to one PAGE, as
1807                  * a one page request is never in violation.
1808                  */
1809                 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
1810                     mddev->queue->max_sectors > (PAGE_SIZE>>9))
1811                         blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
1812
1813                 disk->head_position = 0;
1814                 if (!test_bit(Faulty, &rdev->flags) && test_bit(In_sync, &rdev->flags))
1815                         conf->working_disks++;
1816         }
1817         conf->raid_disks = mddev->raid_disks;
1818         conf->mddev = mddev;
1819         spin_lock_init(&conf->device_lock);
1820         INIT_LIST_HEAD(&conf->retry_list);
1821         if (conf->working_disks == 1)
1822                 mddev->recovery_cp = MaxSector;
1823
1824         spin_lock_init(&conf->resync_lock);
1825         init_waitqueue_head(&conf->wait_barrier);
1826
1827         bio_list_init(&conf->pending_bio_list);
1828         bio_list_init(&conf->flushing_bio_list);
1829
1830         if (!conf->working_disks) {
1831                 printk(KERN_ERR "raid1: no operational mirrors for %s\n",
1832                         mdname(mddev));
1833                 goto out_free_conf;
1834         }
1835
1836         mddev->degraded = 0;
1837         for (i = 0; i < conf->raid_disks; i++) {
1838
1839                 disk = conf->mirrors + i;
1840
1841                 if (!disk->rdev) {
1842                         disk->head_position = 0;
1843                         mddev->degraded++;
1844                 }
1845         }
1846
1847         /*
1848          * find the first working one and use it as a starting point
1849          * to read balancing.
1850          */
1851         for (j = 0; j < conf->raid_disks &&
1852                      (!conf->mirrors[j].rdev ||
1853                       !test_bit(In_sync, &conf->mirrors[j].rdev->flags)) ; j++)
1854                 /* nothing */;
1855         conf->last_used = j;
1856
1857
1858         mddev->thread = md_register_thread(raid1d, mddev, "%s_raid1");
1859         if (!mddev->thread) {
1860                 printk(KERN_ERR
1861                        "raid1: couldn't allocate thread for %s\n",
1862                        mdname(mddev));
1863                 goto out_free_conf;
1864         }
1865
1866         printk(KERN_INFO
1867                 "raid1: raid set %s active with %d out of %d mirrors\n",
1868                 mdname(mddev), mddev->raid_disks - mddev->degraded,
1869                 mddev->raid_disks);
1870         /*
1871          * Ok, everything is just fine now
1872          */
1873         mddev->array_size = mddev->size;
1874
1875         mddev->queue->unplug_fn = raid1_unplug;
1876         mddev->queue->issue_flush_fn = raid1_issue_flush;
1877
1878         return 0;
1879
1880 out_no_mem:
1881         printk(KERN_ERR "raid1: couldn't allocate memory for %s\n",
1882                mdname(mddev));
1883
1884 out_free_conf:
1885         if (conf) {
1886                 if (conf->r1bio_pool)
1887                         mempool_destroy(conf->r1bio_pool);
1888                 kfree(conf->mirrors);
1889                 put_page(conf->tmppage);
1890                 kfree(conf->poolinfo);
1891                 kfree(conf);
1892                 mddev->private = NULL;
1893         }
1894 out:
1895         return -EIO;
1896 }
1897
1898 static int stop(mddev_t *mddev)
1899 {
1900         conf_t *conf = mddev_to_conf(mddev);
1901         struct bitmap *bitmap = mddev->bitmap;
1902         int behind_wait = 0;
1903
1904         /* wait for behind writes to complete */
1905         while (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
1906                 behind_wait++;
1907                 printk(KERN_INFO "raid1: behind writes in progress on device %s, waiting to stop (%d)\n", mdname(mddev), behind_wait);
1908                 set_current_state(TASK_UNINTERRUPTIBLE);
1909                 schedule_timeout(HZ); /* wait a second */
1910                 /* need to kick something here to make sure I/O goes? */
1911         }
1912
1913         md_unregister_thread(mddev->thread);
1914         mddev->thread = NULL;
1915         blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
1916         if (conf->r1bio_pool)
1917                 mempool_destroy(conf->r1bio_pool);
1918         kfree(conf->mirrors);
1919         kfree(conf->poolinfo);
1920         kfree(conf);
1921         mddev->private = NULL;
1922         return 0;
1923 }
1924
1925 static int raid1_resize(mddev_t *mddev, sector_t sectors)
1926 {
1927         /* no resync is happening, and there is enough space
1928          * on all devices, so we can resize.
1929          * We need to make sure resync covers any new space.
1930          * If the array is shrinking we should possibly wait until
1931          * any io in the removed space completes, but it hardly seems
1932          * worth it.
1933          */
1934         mddev->array_size = sectors>>1;
1935         set_capacity(mddev->gendisk, mddev->array_size << 1);
1936         mddev->changed = 1;
1937         if (mddev->array_size > mddev->size && mddev->recovery_cp == MaxSector) {
1938                 mddev->recovery_cp = mddev->size << 1;
1939                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
1940         }
1941         mddev->size = mddev->array_size;
1942         mddev->resync_max_sectors = sectors;
1943         return 0;
1944 }
1945
1946 static int raid1_reshape(mddev_t *mddev, int raid_disks)
1947 {
1948         /* We need to:
1949          * 1/ resize the r1bio_pool
1950          * 2/ resize conf->mirrors
1951          *
1952          * We allocate a new r1bio_pool if we can.
1953          * Then raise a device barrier and wait until all IO stops.
1954          * Then resize conf->mirrors and swap in the new r1bio pool.
1955          *
1956          * At the same time, we "pack" the devices so that all the missing
1957          * devices have the higher raid_disk numbers.
1958          */
1959         mempool_t *newpool, *oldpool;
1960         struct pool_info *newpoolinfo;
1961         mirror_info_t *newmirrors;
1962         conf_t *conf = mddev_to_conf(mddev);
1963         int cnt;
1964
1965         int d, d2;
1966
1967         if (raid_disks < conf->raid_disks) {
1968                 cnt=0;
1969                 for (d= 0; d < conf->raid_disks; d++)
1970                         if (conf->mirrors[d].rdev)
1971                                 cnt++;
1972                 if (cnt > raid_disks)
1973                         return -EBUSY;
1974         }
1975
1976         newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
1977         if (!newpoolinfo)
1978                 return -ENOMEM;
1979         newpoolinfo->mddev = mddev;
1980         newpoolinfo->raid_disks = raid_disks;
1981
1982         newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
1983                                  r1bio_pool_free, newpoolinfo);
1984         if (!newpool) {
1985                 kfree(newpoolinfo);
1986                 return -ENOMEM;
1987         }
1988         newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
1989         if (!newmirrors) {
1990                 kfree(newpoolinfo);
1991                 mempool_destroy(newpool);
1992                 return -ENOMEM;
1993         }
1994
1995         raise_barrier(conf);
1996
1997         /* ok, everything is stopped */
1998         oldpool = conf->r1bio_pool;
1999         conf->r1bio_pool = newpool;
2000
2001         for (d=d2=0; d < conf->raid_disks; d++)
2002                 if (conf->mirrors[d].rdev) {
2003                         conf->mirrors[d].rdev->raid_disk = d2;
2004                         newmirrors[d2++].rdev = conf->mirrors[d].rdev;
2005                 }
2006         kfree(conf->mirrors);
2007         conf->mirrors = newmirrors;
2008         kfree(conf->poolinfo);
2009         conf->poolinfo = newpoolinfo;
2010
2011         mddev->degraded += (raid_disks - conf->raid_disks);
2012         conf->raid_disks = mddev->raid_disks = raid_disks;
2013
2014         conf->last_used = 0; /* just make sure it is in-range */
2015         lower_barrier(conf);
2016
2017         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2018         md_wakeup_thread(mddev->thread);
2019
2020         mempool_destroy(oldpool);
2021         return 0;
2022 }
2023
2024 static void raid1_quiesce(mddev_t *mddev, int state)
2025 {
2026         conf_t *conf = mddev_to_conf(mddev);
2027
2028         switch(state) {
2029         case 1:
2030                 raise_barrier(conf);
2031                 break;
2032         case 0:
2033                 lower_barrier(conf);
2034                 break;
2035         }
2036 }
2037
2038
2039 static mdk_personality_t raid1_personality =
2040 {
2041         .name           = "raid1",
2042         .owner          = THIS_MODULE,
2043         .make_request   = make_request,
2044         .run            = run,
2045         .stop           = stop,
2046         .status         = status,
2047         .error_handler  = error,
2048         .hot_add_disk   = raid1_add_disk,
2049         .hot_remove_disk= raid1_remove_disk,
2050         .spare_active   = raid1_spare_active,
2051         .sync_request   = sync_request,
2052         .resize         = raid1_resize,
2053         .reshape        = raid1_reshape,
2054         .quiesce        = raid1_quiesce,
2055 };
2056
2057 static int __init raid_init(void)
2058 {
2059         return register_md_personality(RAID1, &raid1_personality);
2060 }
2061
2062 static void raid_exit(void)
2063 {
2064         unregister_md_personality(RAID1);
2065 }
2066
2067 module_init(raid_init);
2068 module_exit(raid_exit);
2069 MODULE_LICENSE("GPL");
2070 MODULE_ALIAS("md-personality-3"); /* RAID1 */