drivers/md/raid1.c

   1 /*
   2  * raid1.c : Multiple Devices driver for Linux
   3  *
   4  * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat
   5  *
   6  * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman
   7  *
   8  * RAID-1 management functions.
   9  *
  10  * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000
  11  *
  12  * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
  13  * Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
  14  *
  15  * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support
  16  * bitmapped intelligence in resync:
  17  *
  18  *      - bitmap marked during normal i/o
  19  *      - bitmap used to skip nondirty blocks during sync
  20  *
  21  * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology:
  22  * - persistent bitmap code
  23  *
  24  * This program is free software; you can redistribute it and/or modify
  25  * it under the terms of the GNU General Public License as published by
  26  * the Free Software Foundation; either version 2, or (at your option)
  27  * any later version.
  28  *
  29  * You should have received a copy of the GNU General Public License
  30  * (for example /usr/src/linux/COPYING); if not, write to the Free
  31  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  32  */
  33
  34 #include <linux/slab.h>
  35 #include <linux/delay.h>
  36 #include <linux/blkdev.h>
  37 #include <linux/seq_file.h>
  38 #include "md.h"
  39 #include "raid1.h"
  40 #include "bitmap.h"
  41
  42 #define DEBUG 0
  43 #if DEBUG
  44 #define PRINTK(x...) printk(x)
  45 #else
  46 #define PRINTK(x...)
  47 #endif
  48
  49 /*
  50  * Number of guaranteed r1bios in case of extreme VM load:
  51  */
  52 #define NR_RAID1_BIOS 256
  53
  54
  55 static void unplug_slaves(mddev_t *mddev);
  56
  57 static void allow_barrier(conf_t *conf);
  58 static void lower_barrier(conf_t *conf);
  59
  60 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
  61 {
  62         struct pool_info *pi = data;
  63         r1bio_t *r1_bio;
  64         int size = offsetof(r1bio_t, bios[pi->raid_disks]);
  65
  66         /* allocate a r1bio with room for raid_disks entries in the bios array */
  67         r1_bio = kzalloc(size, gfp_flags);
  68         if (!r1_bio && pi->mddev)
  69                 unplug_slaves(pi->mddev);
  70
  71         return r1_bio;
  72 }
  73
  74 static void r1bio_pool_free(void *r1_bio, void *data)
  75 {
  76         kfree(r1_bio);
  77 }
  78
  79 #define RESYNC_BLOCK_SIZE (64*1024)
  80 //#define RESYNC_BLOCK_SIZE PAGE_SIZE
  81 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
  82 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
  83 #define RESYNC_WINDOW (2048*1024)
  84
  85 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
  86 {
  87         struct pool_info *pi = data;
  88         struct page *page;
  89         r1bio_t *r1_bio;
  90         struct bio *bio;
  91         int i, j;
  92
  93         r1_bio = r1bio_pool_alloc(gfp_flags, pi);
  94         if (!r1_bio) {
  95                 unplug_slaves(pi->mddev);
  96                 return NULL;
  97         }
  98
  99         /*
 100          * Allocate bios : 1 for reading, n-1 for writing
 101          */
 102         for (j = pi->raid_disks ; j-- ; ) {
 103                 bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
 104                 if (!bio)
 105                         goto out_free_bio;
 106                 r1_bio->bios[j] = bio;
 107         }
 108         /*
 109          * Allocate RESYNC_PAGES data pages and attach them to
 110          * the first bio.
 111          * If this is a user-requested check/repair, allocate
 112          * RESYNC_PAGES for each bio.
 113          */
 114         if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
 115                 j = pi->raid_disks;
 116         else
 117                 j = 1;
 118         while(j--) {
 119                 bio = r1_bio->bios[j];
 120                 for (i = 0; i < RESYNC_PAGES; i++) {
 121                         page = alloc_page(gfp_flags);
 122                         if (unlikely(!page))
 123                                 goto out_free_pages;
 124
 125                         bio->bi_io_vec[i].bv_page = page;
 126                         bio->bi_vcnt = i+1;
 127                 }
 128         }
 129         /* If not user-requests, copy the page pointers to all bios */
 130         if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
 131                 for (i=0; i<RESYNC_PAGES ; i++)
 132                         for (j=1; j<pi->raid_disks; j++)
 133                                 r1_bio->bios[j]->bi_io_vec[i].bv_page =
 134                                         r1_bio->bios[0]->bi_io_vec[i].bv_page;
 135         }
 136
 137         r1_bio->master_bio = NULL;
 138
 139         return r1_bio;
 140
 141 out_free_pages:
 142         for (j=0 ; j < pi->raid_disks; j++)
 143                 for (i=0; i < r1_bio->bios[j]->bi_vcnt ; i++)
 144                         put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
 145         j = -1;
 146 out_free_bio:
 147         while ( ++j < pi->raid_disks )
 148                 bio_put(r1_bio->bios[j]);
 149         r1bio_pool_free(r1_bio, data);
 150         return NULL;
 151 }
 152
 153 static void r1buf_pool_free(void *__r1_bio, void *data)
 154 {
 155         struct pool_info *pi = data;
 156         int i,j;
 157         r1bio_t *r1bio = __r1_bio;
 158
 159         for (i = 0; i < RESYNC_PAGES; i++)
 160                 for (j = pi->raid_disks; j-- ;) {
 161                         if (j == 0 ||
 162                             r1bio->bios[j]->bi_io_vec[i].bv_page !=
 163                             r1bio->bios[0]->bi_io_vec[i].bv_page)
 164                                 safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page);
 165                 }
 166         for (i=0 ; i < pi->raid_disks; i++)
 167                 bio_put(r1bio->bios[i]);
 168
 169         r1bio_pool_free(r1bio, data);
 170 }
 171
 172 static void put_all_bios(conf_t *conf, r1bio_t *r1_bio)
 173 {
 174         int i;
 175
 176         for (i = 0; i < conf->raid_disks; i++) {
 177                 struct bio **bio = r1_bio->bios + i;
 178                 if (*bio && *bio != IO_BLOCKED)
 179                         bio_put(*bio);
 180                 *bio = NULL;
 181         }
 182 }
 183
 184 static void free_r1bio(r1bio_t *r1_bio)
 185 {
 186         conf_t *conf = r1_bio->mddev->private;
 187
 188         /*
 189          * Wake up any possible resync thread that waits for the device
 190          * to go idle.
 191          */
 192         allow_barrier(conf);
 193
 194         put_all_bios(conf, r1_bio);
 195         mempool_free(r1_bio, conf->r1bio_pool);
 196 }
 197
 198 static void put_buf(r1bio_t *r1_bio)
 199 {
 200         conf_t *conf = r1_bio->mddev->private;
 201         int i;
 202
 203         for (i=0; i<conf->raid_disks; i++) {
 204                 struct bio *bio = r1_bio->bios[i];
 205                 if (bio->bi_end_io)
 206                         rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
 207         }
 208
 209         mempool_free(r1_bio, conf->r1buf_pool);
 210
 211         lower_barrier(conf);
 212 }
 213
 214 static void reschedule_retry(r1bio_t *r1_bio)
 215 {
 216         unsigned long flags;
 217         mddev_t *mddev = r1_bio->mddev;
 218         conf_t *conf = mddev->private;
 219
 220         spin_lock_irqsave(&conf->device_lock, flags);
 221         list_add(&r1_bio->retry_list, &conf->retry_list);
 222         conf->nr_queued ++;
 223         spin_unlock_irqrestore(&conf->device_lock, flags);
 224
 225         wake_up(&conf->wait_barrier);
 226         md_wakeup_thread(mddev->thread);
 227 }
 228
 229 /*
 230  * raid_end_bio_io() is called when we have finished servicing a mirrored
 231  * operation and are ready to return a success/failure code to the buffer
 232  * cache layer.
 233  */
 234 static void raid_end_bio_io(r1bio_t *r1_bio)
 235 {
 236         struct bio *bio = r1_bio->master_bio;
 237
 238         /* if nobody has done the final endio yet, do it now */
 239         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 240                 PRINTK(KERN_DEBUG "raid1: sync end %s on sectors %llu-%llu\n",
 241                         (bio_data_dir(bio) == WRITE) ? "write" : "read",
 242                         (unsigned long long) bio->bi_sector,
 243                         (unsigned long long) bio->bi_sector +
 244                                 (bio->bi_size >> 9) - 1);
 245
 246                 bio_endio(bio,
 247                         test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO);
 248         }
 249         free_r1bio(r1_bio);
 250 }
 251
 252 /*
 253  * Update disk head position estimator based on IRQ completion info.
 254  */
 255 static inline void update_head_pos(int disk, r1bio_t *r1_bio)
 256 {
 257         conf_t *conf = r1_bio->mddev->private;
 258
 259         conf->mirrors[disk].head_position =
 260                 r1_bio->sector + (r1_bio->sectors);
 261 }
 262
 263 static void raid1_end_read_request(struct bio *bio, int error)
 264 {
 265         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 266         r1bio_t *r1_bio = bio->bi_private;
 267         int mirror;
 268         conf_t *conf = r1_bio->mddev->private;
 269
 270         mirror = r1_bio->read_disk;
 271         /*
 272          * this branch is our 'one mirror IO has finished' event handler:
 273          */
 274         update_head_pos(mirror, r1_bio);
 275
 276         if (uptodate)
 277                 set_bit(R1BIO_Uptodate, &r1_bio->state);
 278         else {
 279                 /* If all other devices have failed, we want to return
 280                  * the error upwards rather than fail the last device.
 281                  * Here we redefine "uptodate" to mean "Don't want to retry"
 282                  */
 283                 unsigned long flags;
 284                 spin_lock_irqsave(&conf->device_lock, flags);
 285                 if (r1_bio->mddev->degraded == conf->raid_disks ||
 286                     (r1_bio->mddev->degraded == conf->raid_disks-1 &&
 287                      !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags)))
 288                         uptodate = 1;
 289                 spin_unlock_irqrestore(&conf->device_lock, flags);
 290         }
 291
 292         if (uptodate)
 293                 raid_end_bio_io(r1_bio);
 294         else {
 295                 /*
 296                  * oops, read error:
 297                  */
 298                 char b[BDEVNAME_SIZE];
 299                 if (printk_ratelimit())
 300                         printk(KERN_ERR "md/raid1:%s: %s: rescheduling sector %llu\n",
 301                                mdname(conf->mddev),
 302                                bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector);
 303                 reschedule_retry(r1_bio);
 304         }
 305
 306         rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
 307 }
 308
 309 static void r1_bio_write_done(r1bio_t *r1_bio, int vcnt, struct bio_vec *bv,
 310                               int behind)
 311 {
 312         if (atomic_dec_and_test(&r1_bio->remaining))
 313         {
 314                 /* it really is the end of this request */
 315                 if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
 316                         /* free extra copy of the data pages */
 317                         int i = vcnt;
 318                         while (i--)
 319                                 safe_put_page(bv[i].bv_page);
 320                 }
 321                 /* clear the bitmap if all writes complete successfully */
 322                 bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
 323                                 r1_bio->sectors,
 324                                 !test_bit(R1BIO_Degraded, &r1_bio->state),
 325                                 behind);
 326                 md_write_end(r1_bio->mddev);
 327                 raid_end_bio_io(r1_bio);
 328         }
 329 }
 330
 331 static void raid1_end_write_request(struct bio *bio, int error)
 332 {
 333         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 334         r1bio_t *r1_bio = bio->bi_private;
 335         int mirror, behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
 336         conf_t *conf = r1_bio->mddev->private;
 337         struct bio *to_put = NULL;
 338
 339
 340         for (mirror = 0; mirror < conf->raid_disks; mirror++)
 341                 if (r1_bio->bios[mirror] == bio)
 342                         break;
 343
 344         /*
 345          * 'one mirror IO has finished' event handler:
 346          */
 347         r1_bio->bios[mirror] = NULL;
 348         to_put = bio;
 349         if (!uptodate) {
 350                 md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
 351                 /* an I/O failed, we can't clear the bitmap */
 352                 set_bit(R1BIO_Degraded, &r1_bio->state);
 353         } else
 354                 /*
 355                  * Set R1BIO_Uptodate in our master bio, so that we
 356                  * will return a good error code for to the higher
 357                  * levels even if IO on some other mirrored buffer
 358                  * fails.
 359                  *
 360                  * The 'master' represents the composite IO operation
 361                  * to user-side. So if something waits for IO, then it
 362                  * will wait for the 'master' bio.
 363                  */
 364                 set_bit(R1BIO_Uptodate, &r1_bio->state);
 365
 366         update_head_pos(mirror, r1_bio);
 367
 368         if (behind) {
 369                 if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags))
 370                         atomic_dec(&r1_bio->behind_remaining);
 371
 372                 /*
 373                  * In behind mode, we ACK the master bio once the I/O
 374                  * has safely reached all non-writemostly
 375                  * disks. Setting the Returned bit ensures that this
 376                  * gets done only once -- we don't ever want to return
 377                  * -EIO here, instead we'll wait
 378                  */
 379                 if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
 380                     test_bit(R1BIO_Uptodate, &r1_bio->state)) {
 381                         /* Maybe we can return now */
 382                         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 383                                 struct bio *mbio = r1_bio->master_bio;
 384                                 PRINTK(KERN_DEBUG "raid1: behind end write sectors %llu-%llu\n",
 385                                        (unsigned long long) mbio->bi_sector,
 386                                        (unsigned long long) mbio->bi_sector +
 387                                        (mbio->bi_size >> 9) - 1);
 388                                 bio_endio(mbio, 0);
 389                         }
 390                 }
 391         }
 392         rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
 393
 394         /*
 395          * Let's see if all mirrored write operations have finished
 396          * already.
 397          */
 398         r1_bio_write_done(r1_bio, bio->bi_vcnt, bio->bi_io_vec, behind);
 399
 400         if (to_put)
 401                 bio_put(to_put);
 402 }
 403
 404
 405 /*
 406  * This routine returns the disk from which the requested read should
 407  * be done. There is a per-array 'next expected sequential IO' sector
 408  * number - if this matches on the next IO then we use the last disk.
 409  * There is also a per-disk 'last know head position' sector that is
 410  * maintained from IRQ contexts, both the normal and the resync IO
 411  * completion handlers update this position correctly. If there is no
 412  * perfect sequential match then we pick the disk whose head is closest.
 413  *
 414  * If there are 2 mirrors in the same 2 devices, performance degrades
 415  * because position is mirror, not device based.
 416  *
 417  * The rdev for the device selected will have nr_pending incremented.
 418  */
 419 static int read_balance(conf_t *conf, r1bio_t *r1_bio)
 420 {
 421         const sector_t this_sector = r1_bio->sector;
 422         int new_disk = conf->last_used, disk = new_disk;
 423         int wonly_disk = -1;
 424         const int sectors = r1_bio->sectors;
 425         sector_t new_distance, current_distance;
 426         mdk_rdev_t *rdev;
 427
 428         rcu_read_lock();
 429         /*
 430          * Check if we can balance. We can balance on the whole
 431          * device if no resync is going on, or below the resync window.
 432          * We take the first readable disk when above the resync window.
 433          */
 434  retry:
 435         if (conf->mddev->recovery_cp < MaxSector &&
 436             (this_sector + sectors >= conf->next_resync)) {
 437                 /* Choose the first operational device, for consistancy */
 438                 new_disk = 0;
 439
 440                 for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
 441                      r1_bio->bios[new_disk] == IO_BLOCKED ||
 442                      !rdev || !test_bit(In_sync, &rdev->flags)
 443                              || test_bit(WriteMostly, &rdev->flags);
 444                      rdev = rcu_dereference(conf->mirrors[++new_disk].rdev)) {
 445
 446                         if (rdev && test_bit(In_sync, &rdev->flags) &&
 447                                 r1_bio->bios[new_disk] != IO_BLOCKED)
 448                                 wonly_disk = new_disk;
 449
 450                         if (new_disk == conf->raid_disks - 1) {
 451                                 new_disk = wonly_disk;
 452                                 break;
 453                         }
 454                 }
 455                 goto rb_out;
 456         }
 457
 458
 459         /* make sure the disk is operational */
 460         for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
 461              r1_bio->bios[new_disk] == IO_BLOCKED ||
 462              !rdev || !test_bit(In_sync, &rdev->flags) ||
 463                      test_bit(WriteMostly, &rdev->flags);
 464              rdev = rcu_dereference(conf->mirrors[new_disk].rdev)) {
 465
 466                 if (rdev && test_bit(In_sync, &rdev->flags) &&
 467                     r1_bio->bios[new_disk] != IO_BLOCKED)
 468                         wonly_disk = new_disk;
 469
 470                 if (new_disk <= 0)
 471                         new_disk = conf->raid_disks;
 472                 new_disk--;
 473                 if (new_disk == disk) {
 474                         new_disk = wonly_disk;
 475                         break;
 476                 }
 477         }
 478
 479         if (new_disk < 0)
 480                 goto rb_out;
 481
 482         disk = new_disk;
 483         /* now disk == new_disk == starting point for search */
 484
 485         /*
 486          * Don't change to another disk for sequential reads:
 487          */
 488         if (conf->next_seq_sect == this_sector)
 489                 goto rb_out;
 490         if (this_sector == conf->mirrors[new_disk].head_position)
 491                 goto rb_out;
 492
 493         current_distance = abs(this_sector - conf->mirrors[disk].head_position);
 494
 495         /* Find the disk whose head is closest */
 496
 497         do {
 498                 if (disk <= 0)
 499                         disk = conf->raid_disks;
 500                 disk--;
 501
 502                 rdev = rcu_dereference(conf->mirrors[disk].rdev);
 503
 504                 if (!rdev || r1_bio->bios[disk] == IO_BLOCKED ||
 505                     !test_bit(In_sync, &rdev->flags) ||
 506                     test_bit(WriteMostly, &rdev->flags))
 507                         continue;
 508
 509                 if (!atomic_read(&rdev->nr_pending)) {
 510                         new_disk = disk;
 511                         break;
 512                 }
 513                 new_distance = abs(this_sector - conf->mirrors[disk].head_position);
 514                 if (new_distance < current_distance) {
 515                         current_distance = new_distance;
 516                         new_disk = disk;
 517                 }
 518         } while (disk != conf->last_used);
 519
 520  rb_out:
 521
 522
 523         if (new_disk >= 0) {
 524                 rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
 525                 if (!rdev)
 526                         goto retry;
 527                 atomic_inc(&rdev->nr_pending);
 528                 if (!test_bit(In_sync, &rdev->flags)) {
 529                         /* cannot risk returning a device that failed
 530                          * before we inc'ed nr_pending
 531                          */
 532                         rdev_dec_pending(rdev, conf->mddev);
 533                         goto retry;
 534                 }
 535                 conf->next_seq_sect = this_sector + sectors;
 536                 conf->last_used = new_disk;
 537         }
 538         rcu_read_unlock();
 539
 540         return new_disk;
 541 }
 542
 543 static void unplug_slaves(mddev_t *mddev)
 544 {
 545         conf_t *conf = mddev->private;
 546         int i;
 547
 548         rcu_read_lock();
 549         for (i=0; i<mddev->raid_disks; i++) {
 550                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
 551                 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
 552                         struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
 553
 554                         atomic_inc(&rdev->nr_pending);
 555                         rcu_read_unlock();
 556
 557                         blk_unplug(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(struct request_queue *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_congested(void *data, int bits)
 575 {
 576         mddev_t *mddev = data;
 577         conf_t *conf = mddev->private;
 578         int i, ret = 0;
 579
 580         if (mddev_congested(mddev, bits))
 581                 return 1;
 582
 583         rcu_read_lock();
 584         for (i = 0; i < mddev->raid_disks; i++) {
 585                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
 586                 if (rdev && !test_bit(Faulty, &rdev->flags)) {
 587                         struct request_queue *q = bdev_get_queue(rdev->bdev);
 588
 589                         /* Note the '|| 1' - when read_balance prefers
 590                          * non-congested targets, it can be removed
 591                          */
 592                         if ((bits & (1<<BDI_async_congested)) || 1)
 593                                 ret |= bdi_congested(&q->backing_dev_info, bits);
 594                         else
 595                                 ret &= bdi_congested(&q->backing_dev_info, bits);
 596                 }
 597         }
 598         rcu_read_unlock();
 599         return ret;
 600 }
 601
 602
 603 static int flush_pending_writes(conf_t *conf)
 604 {
 605         /* Any writes that have been queued but are awaiting
 606          * bitmap updates get flushed here.
 607          * We return 1 if any requests were actually submitted.
 608          */
 609         int rv = 0;
 610
 611         spin_lock_irq(&conf->device_lock);
 612
 613         if (conf->pending_bio_list.head) {
 614                 struct bio *bio;
 615                 bio = bio_list_get(&conf->pending_bio_list);
 616                 blk_remove_plug(conf->mddev->queue);
 617                 spin_unlock_irq(&conf->device_lock);
 618                 /* flush any pending bitmap writes to
 619                  * disk before proceeding w/ I/O */
 620                 bitmap_unplug(conf->mddev->bitmap);
 621
 622                 while (bio) { /* submit pending writes */
 623                         struct bio *next = bio->bi_next;
 624                         bio->bi_next = NULL;
 625                         generic_make_request(bio);
 626                         bio = next;
 627                 }
 628                 rv = 1;
 629         } else
 630                 spin_unlock_irq(&conf->device_lock);
 631         return rv;
 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         BUG_ON(conf->barrier <= 0);
 682         spin_lock_irqsave(&conf->resync_lock, flags);
 683         conf->barrier--;
 684         spin_unlock_irqrestore(&conf->resync_lock, flags);
 685         wake_up(&conf->wait_barrier);
 686 }
 687
 688 static void wait_barrier(conf_t *conf)
 689 {
 690         spin_lock_irq(&conf->resync_lock);
 691         if (conf->barrier) {
 692                 conf->nr_waiting++;
 693                 wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
 694                                     conf->resync_lock,
 695                                     raid1_unplug(conf->mddev->queue));
 696                 conf->nr_waiting--;
 697         }
 698         conf->nr_pending++;
 699         spin_unlock_irq(&conf->resync_lock);
 700 }
 701
 702 static void allow_barrier(conf_t *conf)
 703 {
 704         unsigned long flags;
 705         spin_lock_irqsave(&conf->resync_lock, flags);
 706         conf->nr_pending--;
 707         spin_unlock_irqrestore(&conf->resync_lock, flags);
 708         wake_up(&conf->wait_barrier);
 709 }
 710
 711 static void freeze_array(conf_t *conf)
 712 {
 713         /* stop syncio and normal IO and wait for everything to
 714          * go quite.
 715          * We increment barrier and nr_waiting, and then
 716          * wait until nr_pending match nr_queued+1
 717          * This is called in the context of one normal IO request
 718          * that has failed. Thus any sync request that might be pending
 719          * will be blocked by nr_pending, and we need to wait for
 720          * pending IO requests to complete or be queued for re-try.
 721          * Thus the number queued (nr_queued) plus this request (1)
 722          * must match the number of pending IOs (nr_pending) before
 723          * we continue.
 724          */
 725         spin_lock_irq(&conf->resync_lock);
 726         conf->barrier++;
 727         conf->nr_waiting++;
 728         wait_event_lock_irq(conf->wait_barrier,
 729                             conf->nr_pending == conf->nr_queued+1,
 730                             conf->resync_lock,
 731                             ({ flush_pending_writes(conf);
 732                                raid1_unplug(conf->mddev->queue); }));
 733         spin_unlock_irq(&conf->resync_lock);
 734 }
 735 static void unfreeze_array(conf_t *conf)
 736 {
 737         /* reverse the effect of the freeze */
 738         spin_lock_irq(&conf->resync_lock);
 739         conf->barrier--;
 740         conf->nr_waiting--;
 741         wake_up(&conf->wait_barrier);
 742         spin_unlock_irq(&conf->resync_lock);
 743 }
 744
 745
 746 /* duplicate the data pages for behind I/O
 747  * We return a list of bio_vec rather than just page pointers
 748  * as it makes freeing easier
 749  */
 750 static struct bio_vec *alloc_behind_pages(struct bio *bio)
 751 {
 752         int i;
 753         struct bio_vec *bvec;
 754         struct bio_vec *pages = kzalloc(bio->bi_vcnt * sizeof(struct bio_vec),
 755                                         GFP_NOIO);
 756         if (unlikely(!pages))
 757                 goto do_sync_io;
 758
 759         bio_for_each_segment(bvec, bio, i) {
 760                 pages[i].bv_page = alloc_page(GFP_NOIO);
 761                 if (unlikely(!pages[i].bv_page))
 762                         goto do_sync_io;
 763                 memcpy(kmap(pages[i].bv_page) + bvec->bv_offset,
 764                         kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
 765                 kunmap(pages[i].bv_page);
 766                 kunmap(bvec->bv_page);
 767         }
 768
 769         return pages;
 770
 771 do_sync_io:
 772         if (pages)
 773                 for (i = 0; i < bio->bi_vcnt && pages[i].bv_page; i++)
 774                         put_page(pages[i].bv_page);
 775         kfree(pages);
 776         PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
 777         return NULL;
 778 }
 779
 780 static int make_request(mddev_t *mddev, struct bio * bio)
 781 {
 782         conf_t *conf = mddev->private;
 783         mirror_info_t *mirror;
 784         r1bio_t *r1_bio;
 785         struct bio *read_bio;
 786         int i, targets = 0, disks;
 787         struct bitmap *bitmap;
 788         unsigned long flags;
 789         struct bio_vec *behind_pages = NULL;
 790         const int rw = bio_data_dir(bio);
 791         const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
 792         const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA));
 793         mdk_rdev_t *blocked_rdev;
 794
 795         /*
 796          * Register the new request and wait if the reconstruction
 797          * thread has put up a bar for new requests.
 798          * Continue immediately if no resync is active currently.
 799          */
 800
 801         md_write_start(mddev, bio); /* wait on superblock update early */
 802
 803         if (bio_data_dir(bio) == WRITE &&
 804             bio->bi_sector + bio->bi_size/512 > mddev->suspend_lo &&
 805             bio->bi_sector < mddev->suspend_hi) {
 806                 /* As the suspend_* range is controlled by
 807                  * userspace, we want an interruptible
 808                  * wait.
 809                  */
 810                 DEFINE_WAIT(w);
 811                 for (;;) {
 812                         flush_signals(current);
 813                         prepare_to_wait(&conf->wait_barrier,
 814                                         &w, TASK_INTERRUPTIBLE);
 815                         if (bio->bi_sector + bio->bi_size/512 <= mddev->suspend_lo ||
 816                             bio->bi_sector >= mddev->suspend_hi)
 817                                 break;
 818                         schedule();
 819                 }
 820                 finish_wait(&conf->wait_barrier, &w);
 821         }
 822
 823         wait_barrier(conf);
 824
 825         bitmap = mddev->bitmap;
 826
 827         /*
 828          * make_request() can abort the operation when READA is being
 829          * used and no empty request is available.
 830          *
 831          */
 832         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
 833
 834         r1_bio->master_bio = bio;
 835         r1_bio->sectors = bio->bi_size >> 9;
 836         r1_bio->state = 0;
 837         r1_bio->mddev = mddev;
 838         r1_bio->sector = bio->bi_sector;
 839
 840         if (rw == READ) {
 841                 /*
 842                  * read balancing logic:
 843                  */
 844                 int rdisk = read_balance(conf, r1_bio);
 845
 846                 if (rdisk < 0) {
 847                         /* couldn't find anywhere to read from */
 848                         raid_end_bio_io(r1_bio);
 849                         return 0;
 850                 }
 851                 mirror = conf->mirrors + rdisk;
 852
 853                 if (test_bit(WriteMostly, &mirror->rdev->flags) &&
 854                     bitmap) {
 855                         /* Reading from a write-mostly device must
 856                          * take care not to over-take any writes
 857                          * that are 'behind'
 858                          */
 859                         wait_event(bitmap->behind_wait,
 860                                    atomic_read(&bitmap->behind_writes) == 0);
 861                 }
 862                 r1_bio->read_disk = rdisk;
 863
 864                 read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
 865
 866                 r1_bio->bios[rdisk] = read_bio;
 867
 868                 read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
 869                 read_bio->bi_bdev = mirror->rdev->bdev;
 870                 read_bio->bi_end_io = raid1_end_read_request;
 871                 read_bio->bi_rw = READ | do_sync;
 872                 read_bio->bi_private = r1_bio;
 873
 874                 generic_make_request(read_bio);
 875                 return 0;
 876         }
 877
 878         /*
 879          * WRITE:
 880          */
 881         /* first select target devices under spinlock and
 882          * inc refcount on their rdev.  Record them by setting
 883          * bios[x] to bio
 884          */
 885         disks = conf->raid_disks;
 886  retry_write:
 887         blocked_rdev = NULL;
 888         rcu_read_lock();
 889         for (i = 0;  i < disks; i++) {
 890                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
 891                 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
 892                         atomic_inc(&rdev->nr_pending);
 893                         blocked_rdev = rdev;
 894                         break;
 895                 }
 896                 if (rdev && !test_bit(Faulty, &rdev->flags)) {
 897                         atomic_inc(&rdev->nr_pending);
 898                         if (test_bit(Faulty, &rdev->flags)) {
 899                                 rdev_dec_pending(rdev, mddev);
 900                                 r1_bio->bios[i] = NULL;
 901                         } else {
 902                                 r1_bio->bios[i] = bio;
 903                                 targets++;
 904                         }
 905                 } else
 906                         r1_bio->bios[i] = NULL;
 907         }
 908         rcu_read_unlock();
 909
 910         if (unlikely(blocked_rdev)) {
 911                 /* Wait for this device to become unblocked */
 912                 int j;
 913
 914                 for (j = 0; j < i; j++)
 915                         if (r1_bio->bios[j])
 916                                 rdev_dec_pending(conf->mirrors[j].rdev, mddev);
 917
 918                 allow_barrier(conf);
 919                 md_wait_for_blocked_rdev(blocked_rdev, mddev);
 920                 wait_barrier(conf);
 921                 goto retry_write;
 922         }
 923
 924         BUG_ON(targets == 0); /* we never fail the last device */
 925
 926         if (targets < conf->raid_disks) {
 927                 /* array is degraded, we will not clear the bitmap
 928                  * on I/O completion (see raid1_end_write_request) */
 929                 set_bit(R1BIO_Degraded, &r1_bio->state);
 930         }
 931
 932         /* do behind I/O ?
 933          * Not if there are too many, or cannot allocate memory,
 934          * or a reader on WriteMostly is waiting for behind writes
 935          * to flush */
 936         if (bitmap &&
 937             (atomic_read(&bitmap->behind_writes)
 938              < mddev->bitmap_info.max_write_behind) &&
 939             !waitqueue_active(&bitmap->behind_wait) &&
 940             (behind_pages = alloc_behind_pages(bio)) != NULL)
 941                 set_bit(R1BIO_BehindIO, &r1_bio->state);
 942
 943         atomic_set(&r1_bio->remaining, 1);
 944         atomic_set(&r1_bio->behind_remaining, 0);
 945
 946         bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors,
 947                                 test_bit(R1BIO_BehindIO, &r1_bio->state));
 948         for (i = 0; i < disks; i++) {
 949                 struct bio *mbio;
 950                 if (!r1_bio->bios[i])
 951                         continue;
 952
 953                 mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
 954                 r1_bio->bios[i] = mbio;
 955
 956                 mbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset;
 957                 mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
 958                 mbio->bi_end_io = raid1_end_write_request;
 959                 mbio->bi_rw = WRITE | do_flush_fua | do_sync;
 960                 mbio->bi_private = r1_bio;
 961
 962                 if (behind_pages) {
 963                         struct bio_vec *bvec;
 964                         int j;
 965
 966                         /* Yes, I really want the '__' version so that
 967                          * we clear any unused pointer in the io_vec, rather
 968                          * than leave them unchanged.  This is important
 969                          * because when we come to free the pages, we won't
 970                          * know the originial bi_idx, so we just free
 971                          * them all
 972                          */
 973                         __bio_for_each_segment(bvec, mbio, j, 0)
 974                                 bvec->bv_page = behind_pages[j].bv_page;
 975                         if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
 976                                 atomic_inc(&r1_bio->behind_remaining);
 977                 }
 978
 979                 atomic_inc(&r1_bio->remaining);
 980                 spin_lock_irqsave(&conf->device_lock, flags);
 981                 bio_list_add(&conf->pending_bio_list, mbio);
 982                 blk_plug_device(mddev->queue);
 983                 spin_unlock_irqrestore(&conf->device_lock, flags);
 984         }
 985         r1_bio_write_done(r1_bio, bio->bi_vcnt, behind_pages, behind_pages != NULL);
 986         kfree(behind_pages); /* the behind pages are attached to the bios now */
 987
 988         /* In case raid1d snuck in to freeze_array */
 989         wake_up(&conf->wait_barrier);
 990
 991         if (do_sync)
 992                 md_wakeup_thread(mddev->thread);
 993
 994         return 0;
 995 }
 996
 997 static void status(struct seq_file *seq, mddev_t *mddev)
 998 {
 999         conf_t *conf = mddev->private;
1000         int i;
1001
1002         seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1003                    conf->raid_disks - mddev->degraded);
1004         rcu_read_lock();
1005         for (i = 0; i < conf->raid_disks; i++) {
1006                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1007                 seq_printf(seq, "%s",
1008                            rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1009         }
1010         rcu_read_unlock();
1011         seq_printf(seq, "]");
1012 }
1013
1014
1015 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
1016 {
1017         char b[BDEVNAME_SIZE];
1018         conf_t *conf = mddev->private;
1019
1020         /*
1021          * If it is not operational, then we have already marked it as dead
1022          * else if it is the last working disks, ignore the error, let the
1023          * next level up know.
1024          * else mark the drive as failed
1025          */
1026         if (test_bit(In_sync, &rdev->flags)
1027             && (conf->raid_disks - mddev->degraded) == 1) {
1028                 /*
1029                  * Don't fail the drive, act as though we were just a
1030                  * normal single drive.
1031                  * However don't try a recovery from this drive as
1032                  * it is very likely to fail.
1033                  */
1034                 mddev->recovery_disabled = 1;
1035                 return;
1036         }
1037         if (test_and_clear_bit(In_sync, &rdev->flags)) {
1038                 unsigned long flags;
1039                 spin_lock_irqsave(&conf->device_lock, flags);
1040                 mddev->degraded++;
1041                 set_bit(Faulty, &rdev->flags);
1042                 spin_unlock_irqrestore(&conf->device_lock, flags);
1043                 /*
1044                  * if recovery is running, make sure it aborts.
1045                  */
1046                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1047         } else
1048                 set_bit(Faulty, &rdev->flags);
1049         set_bit(MD_CHANGE_DEVS, &mddev->flags);
1050         printk(KERN_ALERT "md/raid1:%s: Disk failure on %s, disabling device.\n"
1051                KERN_ALERT "md/raid1:%s: Operation continuing on %d devices.\n",
1052                mdname(mddev), bdevname(rdev->bdev, b),
1053                mdname(mddev), conf->raid_disks - mddev->degraded);
1054 }
1055
1056 static void print_conf(conf_t *conf)
1057 {
1058         int i;
1059
1060         printk(KERN_DEBUG "RAID1 conf printout:\n");
1061         if (!conf) {
1062                 printk(KERN_DEBUG "(!conf)\n");
1063                 return;
1064         }
1065         printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1066                 conf->raid_disks);
1067
1068         rcu_read_lock();
1069         for (i = 0; i < conf->raid_disks; i++) {
1070                 char b[BDEVNAME_SIZE];
1071                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1072                 if (rdev)
1073                         printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
1074                                i, !test_bit(In_sync, &rdev->flags),
1075                                !test_bit(Faulty, &rdev->flags),
1076                                bdevname(rdev->bdev,b));
1077         }
1078         rcu_read_unlock();
1079 }
1080
1081 static void close_sync(conf_t *conf)
1082 {
1083         wait_barrier(conf);
1084         allow_barrier(conf);
1085
1086         mempool_destroy(conf->r1buf_pool);
1087         conf->r1buf_pool = NULL;
1088 }
1089
1090 static int raid1_spare_active(mddev_t *mddev)
1091 {
1092         int i;
1093         conf_t *conf = mddev->private;
1094         int count = 0;
1095         unsigned long flags;
1096
1097         /*
1098          * Find all failed disks within the RAID1 configuration
1099          * and mark them readable.
1100          * Called under mddev lock, so rcu protection not needed.
1101          */
1102         for (i = 0; i < conf->raid_disks; i++) {
1103                 mdk_rdev_t *rdev = conf->mirrors[i].rdev;
1104                 if (rdev
1105                     && !test_bit(Faulty, &rdev->flags)
1106                     && !test_and_set_bit(In_sync, &rdev->flags)) {
1107                         count++;
1108                         sysfs_notify_dirent(rdev->sysfs_state);
1109                 }
1110         }
1111         spin_lock_irqsave(&conf->device_lock, flags);
1112         mddev->degraded -= count;
1113         spin_unlock_irqrestore(&conf->device_lock, flags);
1114
1115         print_conf(conf);
1116         return count;
1117 }
1118
1119
1120 static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
1121 {
1122         conf_t *conf = mddev->private;
1123         int err = -EEXIST;
1124         int mirror = 0;
1125         mirror_info_t *p;
1126         int first = 0;
1127         int last = mddev->raid_disks - 1;
1128
1129         if (rdev->raid_disk >= 0)
1130                 first = last = rdev->raid_disk;
1131
1132         for (mirror = first; mirror <= last; mirror++)
1133                 if ( !(p=conf->mirrors+mirror)->rdev) {
1134
1135                         disk_stack_limits(mddev->gendisk, rdev->bdev,
1136                                           rdev->data_offset << 9);
1137                         /* as we don't honour merge_bvec_fn, we must
1138                          * never risk violating it, so limit
1139                          * ->max_segments to one lying with a single
1140                          * page, as a one page request is never in
1141                          * violation.
1142                          */
1143                         if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
1144                                 blk_queue_max_segments(mddev->queue, 1);
1145                                 blk_queue_segment_boundary(mddev->queue,
1146                                                            PAGE_CACHE_SIZE - 1);
1147                         }
1148
1149                         p->head_position = 0;
1150                         rdev->raid_disk = mirror;
1151                         err = 0;
1152                         /* As all devices are equivalent, we don't need a full recovery
1153                          * if this was recently any drive of the array
1154                          */
1155                         if (rdev->saved_raid_disk < 0)
1156                                 conf->fullsync = 1;
1157                         rcu_assign_pointer(p->rdev, rdev);
1158                         break;
1159                 }
1160         md_integrity_add_rdev(rdev, mddev);
1161         print_conf(conf);
1162         return err;
1163 }
1164
1165 static int raid1_remove_disk(mddev_t *mddev, int number)
1166 {
1167         conf_t *conf = mddev->private;
1168         int err = 0;
1169         mdk_rdev_t *rdev;
1170         mirror_info_t *p = conf->mirrors+ number;
1171
1172         print_conf(conf);
1173         rdev = p->rdev;
1174         if (rdev) {
1175                 if (test_bit(In_sync, &rdev->flags) ||
1176                     atomic_read(&rdev->nr_pending)) {
1177                         err = -EBUSY;
1178                         goto abort;
1179                 }
1180                 /* Only remove non-faulty devices is recovery
1181                  * is not possible.
1182                  */
1183                 if (!test_bit(Faulty, &rdev->flags) &&
1184                     mddev->degraded < conf->raid_disks) {
1185                         err = -EBUSY;
1186                         goto abort;
1187                 }
1188                 p->rdev = NULL;
1189                 synchronize_rcu();
1190                 if (atomic_read(&rdev->nr_pending)) {
1191                         /* lost the race, try later */
1192                         err = -EBUSY;
1193                         p->rdev = rdev;
1194                         goto abort;
1195                 }
1196                 md_integrity_register(mddev);
1197         }
1198 abort:
1199
1200         print_conf(conf);
1201         return err;
1202 }
1203
1204
1205 static void end_sync_read(struct bio *bio, int error)
1206 {
1207         r1bio_t *r1_bio = bio->bi_private;
1208         int i;
1209
1210         for (i=r1_bio->mddev->raid_disks; i--; )
1211                 if (r1_bio->bios[i] == bio)
1212                         break;
1213         BUG_ON(i < 0);
1214         update_head_pos(i, r1_bio);
1215         /*
1216          * we have read a block, now it needs to be re-written,
1217          * or re-read if the read failed.
1218          * We don't do much here, just schedule handling by raid1d
1219          */
1220         if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1221                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1222
1223         if (atomic_dec_and_test(&r1_bio->remaining))
1224                 reschedule_retry(r1_bio);
1225 }
1226
1227 static void end_sync_write(struct bio *bio, int error)
1228 {
1229         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1230         r1bio_t *r1_bio = bio->bi_private;
1231         mddev_t *mddev = r1_bio->mddev;
1232         conf_t *conf = mddev->private;
1233         int i;
1234         int mirror=0;
1235
1236         for (i = 0; i < conf->raid_disks; i++)
1237                 if (r1_bio->bios[i] == bio) {
1238                         mirror = i;
1239                         break;
1240                 }
1241         if (!uptodate) {
1242                 sector_t sync_blocks = 0;
1243                 sector_t s = r1_bio->sector;
1244                 long sectors_to_go = r1_bio->sectors;
1245                 /* make sure these bits doesn't get cleared. */
1246                 do {
1247                         bitmap_end_sync(mddev->bitmap, s,
1248                                         &sync_blocks, 1);
1249                         s += sync_blocks;
1250                         sectors_to_go -= sync_blocks;
1251                 } while (sectors_to_go > 0);
1252                 md_error(mddev, conf->mirrors[mirror].rdev);
1253         }
1254
1255         update_head_pos(mirror, r1_bio);
1256
1257         if (atomic_dec_and_test(&r1_bio->remaining)) {
1258                 sector_t s = r1_bio->sectors;
1259                 put_buf(r1_bio);
1260                 md_done_sync(mddev, s, uptodate);
1261         }
1262 }
1263
1264 static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
1265 {
1266         conf_t *conf = mddev->private;
1267         int i;
1268         int disks = conf->raid_disks;
1269         struct bio *bio, *wbio;
1270
1271         bio = r1_bio->bios[r1_bio->read_disk];
1272
1273
1274         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1275                 /* We have read all readable devices.  If we haven't
1276                  * got the block, then there is no hope left.
1277                  * If we have, then we want to do a comparison
1278                  * and skip the write if everything is the same.
1279                  * If any blocks failed to read, then we need to
1280                  * attempt an over-write
1281                  */
1282                 int primary;
1283                 if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1284                         for (i=0; i<mddev->raid_disks; i++)
1285                                 if (r1_bio->bios[i]->bi_end_io == end_sync_read)
1286                                         md_error(mddev, conf->mirrors[i].rdev);
1287
1288                         md_done_sync(mddev, r1_bio->sectors, 1);
1289                         put_buf(r1_bio);
1290                         return;
1291                 }
1292                 for (primary=0; primary<mddev->raid_disks; primary++)
1293                         if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1294                             test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
1295                                 r1_bio->bios[primary]->bi_end_io = NULL;
1296                                 rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1297                                 break;
1298                         }
1299                 r1_bio->read_disk = primary;
1300                 for (i=0; i<mddev->raid_disks; i++)
1301                         if (r1_bio->bios[i]->bi_end_io == end_sync_read) {
1302                                 int j;
1303                                 int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
1304                                 struct bio *pbio = r1_bio->bios[primary];
1305                                 struct bio *sbio = r1_bio->bios[i];
1306
1307                                 if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
1308                                         for (j = vcnt; j-- ; ) {
1309                                                 struct page *p, *s;
1310                                                 p = pbio->bi_io_vec[j].bv_page;
1311                                                 s = sbio->bi_io_vec[j].bv_page;
1312                                                 if (memcmp(page_address(p),
1313                                                            page_address(s),
1314                                                            PAGE_SIZE))
1315                                                         break;
1316                                         }
1317                                 } else
1318                                         j = 0;
1319                                 if (j >= 0)
1320                                         mddev->resync_mismatches += r1_bio->sectors;
1321                                 if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
1322                                               && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
1323                                         sbio->bi_end_io = NULL;
1324                                         rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1325                                 } else {
1326                                         /* fixup the bio for reuse */
1327                                         int size;
1328                                         sbio->bi_vcnt = vcnt;
1329                                         sbio->bi_size = r1_bio->sectors << 9;
1330                                         sbio->bi_idx = 0;
1331                                         sbio->bi_phys_segments = 0;
1332                                         sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1333                                         sbio->bi_flags |= 1 << BIO_UPTODATE;
1334                                         sbio->bi_next = NULL;
1335                                         sbio->bi_sector = r1_bio->sector +
1336                                                 conf->mirrors[i].rdev->data_offset;
1337                                         sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1338                                         size = sbio->bi_size;
1339                                         for (j = 0; j < vcnt ; j++) {
1340                                                 struct bio_vec *bi;
1341                                                 bi = &sbio->bi_io_vec[j];
1342                                                 bi->bv_offset = 0;
1343                                                 if (size > PAGE_SIZE)
1344                                                         bi->bv_len = PAGE_SIZE;
1345                                                 else
1346                                                         bi->bv_len = size;
1347                                                 size -= PAGE_SIZE;
1348                                                 memcpy(page_address(bi->bv_page),
1349                                                        page_address(pbio->bi_io_vec[j].bv_page),
1350                                                        PAGE_SIZE);
1351                                         }
1352
1353                                 }
1354                         }
1355         }
1356         if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1357                 /* ouch - failed to read all of that.
1358                  * Try some synchronous reads of other devices to get
1359                  * good data, much like with normal read errors.  Only
1360                  * read into the pages we already have so we don't
1361                  * need to re-issue the read request.
1362                  * We don't need to freeze the array, because being in an
1363                  * active sync request, there is no normal IO, and
1364                  * no overlapping syncs.
1365                  */
1366                 sector_t sect = r1_bio->sector;
1367                 int sectors = r1_bio->sectors;
1368                 int idx = 0;
1369
1370                 while(sectors) {
1371                         int s = sectors;
1372                         int d = r1_bio->read_disk;
1373                         int success = 0;
1374                         mdk_rdev_t *rdev;
1375
1376                         if (s > (PAGE_SIZE>>9))
1377                                 s = PAGE_SIZE >> 9;
1378                         do {
1379                                 if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1380                                         /* No rcu protection needed here devices
1381                                          * can only be removed when no resync is
1382                                          * active, and resync is currently active
1383                                          */
1384                                         rdev = conf->mirrors[d].rdev;
1385                                         if (sync_page_io(rdev,
1386                                                          sect + rdev->data_offset,
1387                                                          s<<9,
1388                                                          bio->bi_io_vec[idx].bv_page,
1389                                                          READ)) {
1390                                                 success = 1;
1391                                                 break;
1392                                         }
1393                                 }
1394                                 d++;
1395                                 if (d == conf->raid_disks)
1396                                         d = 0;
1397                         } while (!success && d != r1_bio->read_disk);
1398
1399                         if (success) {
1400                                 int start = d;
1401                                 /* write it back and re-read */
1402                                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1403                                 while (d != r1_bio->read_disk) {
1404                                         if (d == 0)
1405                                                 d = conf->raid_disks;
1406                                         d--;
1407                                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1408                                                 continue;
1409                                         rdev = conf->mirrors[d].rdev;
1410                                         atomic_add(s, &rdev->corrected_errors);
1411                                         if (sync_page_io(rdev,
1412                                                          sect + rdev->data_offset,
1413                                                          s<<9,
1414                                                          bio->bi_io_vec[idx].bv_page,
1415                                                          WRITE) == 0)
1416                                                 md_error(mddev, rdev);
1417                                 }
1418                                 d = start;
1419                                 while (d != r1_bio->read_disk) {
1420                                         if (d == 0)
1421                                                 d = conf->raid_disks;
1422                                         d--;
1423                                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1424                                                 continue;
1425                                         rdev = conf->mirrors[d].rdev;
1426                                         if (sync_page_io(rdev,
1427                                                          sect + rdev->data_offset,
1428                                                          s<<9,
1429                                                          bio->bi_io_vec[idx].bv_page,
1430                                                          READ) == 0)
1431                                                 md_error(mddev, rdev);
1432                                 }
1433                         } else {
1434                                 char b[BDEVNAME_SIZE];
1435                                 /* Cannot read from anywhere, array is toast */
1436                                 md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
1437                                 printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O read error"
1438                                        " for block %llu\n",
1439                                        mdname(mddev),
1440                                        bdevname(bio->bi_bdev, b),
1441                                        (unsigned long long)r1_bio->sector);
1442                                 md_done_sync(mddev, r1_bio->sectors, 0);
1443                                 put_buf(r1_bio);
1444                                 return;
1445                         }
1446                         sectors -= s;
1447                         sect += s;
1448                         idx ++;
1449                 }
1450         }
1451
1452         /*
1453          * schedule writes
1454          */
1455         atomic_set(&r1_bio->remaining, 1);
1456         for (i = 0; i < disks ; i++) {
1457                 wbio = r1_bio->bios[i];
1458                 if (wbio->bi_end_io == NULL ||
1459                     (wbio->bi_end_io == end_sync_read &&
1460                      (i == r1_bio->read_disk ||
1461                       !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
1462                         continue;
1463
1464                 wbio->bi_rw = WRITE;
1465                 wbio->bi_end_io = end_sync_write;
1466                 atomic_inc(&r1_bio->remaining);
1467                 md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1468
1469                 generic_make_request(wbio);
1470         }
1471
1472         if (atomic_dec_and_test(&r1_bio->remaining)) {
1473                 /* if we're here, all write(s) have completed, so clean up */
1474                 md_done_sync(mddev, r1_bio->sectors, 1);
1475                 put_buf(r1_bio);
1476         }
1477 }
1478
1479 /*
1480  * This is a kernel thread which:
1481  *
1482  *      1.      Retries failed read operations on working mirrors.
1483  *      2.      Updates the raid superblock when problems encounter.
1484  *      3.      Performs writes following reads for array syncronising.
1485  */
1486
1487 static void fix_read_error(conf_t *conf, int read_disk,
1488                            sector_t sect, int sectors)
1489 {
1490         mddev_t *mddev = conf->mddev;
1491         while(sectors) {
1492                 int s = sectors;
1493                 int d = read_disk;
1494                 int success = 0;
1495                 int start;
1496                 mdk_rdev_t *rdev;
1497
1498                 if (s > (PAGE_SIZE>>9))
1499                         s = PAGE_SIZE >> 9;
1500
1501                 do {
1502                         /* Note: no rcu protection needed here
1503                          * as this is synchronous in the raid1d thread
1504                          * which is the thread that might remove
1505                          * a device.  If raid1d ever becomes multi-threaded....
1506                          */
1507                         rdev = conf->mirrors[d].rdev;
1508                         if (rdev &&
1509                             test_bit(In_sync, &rdev->flags) &&
1510                             sync_page_io(rdev,
1511                                          sect + rdev->data_offset,
1512                                          s<<9,
1513                                          conf->tmppage, READ))
1514                                 success = 1;
1515                         else {
1516                                 d++;
1517                                 if (d == conf->raid_disks)
1518                                         d = 0;
1519                         }
1520                 } while (!success && d != read_disk);
1521
1522                 if (!success) {
1523                         /* Cannot read from anywhere -- bye bye array */
1524                         md_error(mddev, conf->mirrors[read_disk].rdev);
1525                         break;
1526                 }
1527                 /* write it back and re-read */
1528                 start = d;
1529                 while (d != read_disk) {
1530                         if (d==0)
1531                                 d = conf->raid_disks;
1532                         d--;
1533                         rdev = conf->mirrors[d].rdev;
1534                         if (rdev &&
1535                             test_bit(In_sync, &rdev->flags)) {
1536                                 if (sync_page_io(rdev,
1537                                                  sect + rdev->data_offset,
1538                                                  s<<9, conf->tmppage, WRITE)
1539                                     == 0)
1540                                         /* Well, this device is dead */
1541                                         md_error(mddev, rdev);
1542                         }
1543                 }
1544                 d = start;
1545                 while (d != read_disk) {
1546                         char b[BDEVNAME_SIZE];
1547                         if (d==0)
1548                                 d = conf->raid_disks;
1549                         d--;
1550                         rdev = conf->mirrors[d].rdev;
1551                         if (rdev &&
1552                             test_bit(In_sync, &rdev->flags)) {
1553                                 if (sync_page_io(rdev,
1554                                                  sect + rdev->data_offset,
1555                                                  s<<9, conf->tmppage, READ)
1556                                     == 0)
1557                                         /* Well, this device is dead */
1558                                         md_error(mddev, rdev);
1559                                 else {
1560                                         atomic_add(s, &rdev->corrected_errors);
1561                                         printk(KERN_INFO
1562                                                "md/raid1:%s: read error corrected "
1563                                                "(%d sectors at %llu on %s)\n",
1564                                                mdname(mddev), s,
1565                                                (unsigned long long)(sect +
1566                                                    rdev->data_offset),
1567                                                bdevname(rdev->bdev, b));
1568                                 }
1569                         }
1570                 }
1571                 sectors -= s;
1572                 sect += s;
1573         }
1574 }
1575
1576 static void raid1d(mddev_t *mddev)
1577 {
1578         r1bio_t *r1_bio;
1579         struct bio *bio;
1580         unsigned long flags;
1581         conf_t *conf = mddev->private;
1582         struct list_head *head = &conf->retry_list;
1583         int unplug=0;
1584         mdk_rdev_t *rdev;
1585
1586         md_check_recovery(mddev);
1587
1588         for (;;) {
1589                 char b[BDEVNAME_SIZE];
1590
1591                 unplug += flush_pending_writes(conf);
1592
1593                 spin_lock_irqsave(&conf->device_lock, flags);
1594                 if (list_empty(head)) {
1595                         spin_unlock_irqrestore(&conf->device_lock, flags);
1596                         break;
1597                 }
1598                 r1_bio = list_entry(head->prev, r1bio_t, retry_list);
1599                 list_del(head->prev);
1600                 conf->nr_queued--;
1601                 spin_unlock_irqrestore(&conf->device_lock, flags);
1602
1603                 mddev = r1_bio->mddev;
1604                 conf = mddev->private;
1605                 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
1606                         sync_request_write(mddev, r1_bio);
1607                         unplug = 1;
1608                 } else {
1609                         int disk;
1610
1611                         /* we got a read error. Maybe the drive is bad.  Maybe just
1612                          * the block and we can fix it.
1613                          * We freeze all other IO, and try reading the block from
1614                          * other devices.  When we find one, we re-write
1615                          * and check it that fixes the read error.
1616                          * This is all done synchronously while the array is
1617                          * frozen
1618                          */
1619                         if (mddev->ro == 0) {
1620                                 freeze_array(conf);
1621                                 fix_read_error(conf, r1_bio->read_disk,
1622                                                r1_bio->sector,
1623                                                r1_bio->sectors);
1624                                 unfreeze_array(conf);
1625                         } else
1626                                 md_error(mddev,
1627                                          conf->mirrors[r1_bio->read_disk].rdev);
1628
1629                         bio = r1_bio->bios[r1_bio->read_disk];
1630                         if ((disk=read_balance(conf, r1_bio)) == -1) {
1631                                 printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O"
1632                                        " read error for block %llu\n",
1633                                        mdname(mddev),
1634                                        bdevname(bio->bi_bdev,b),
1635                                        (unsigned long long)r1_bio->sector);
1636                                 raid_end_bio_io(r1_bio);
1637                         } else {
1638                                 const unsigned long do_sync = r1_bio->master_bio->bi_rw & REQ_SYNC;
1639                                 r1_bio->bios[r1_bio->read_disk] =
1640                                         mddev->ro ? IO_BLOCKED : NULL;
1641                                 r1_bio->read_disk = disk;
1642                                 bio_put(bio);
1643                                 bio = bio_clone_mddev(r1_bio->master_bio,
1644                                                       GFP_NOIO, mddev);
1645                                 r1_bio->bios[r1_bio->read_disk] = bio;
1646                                 rdev = conf->mirrors[disk].rdev;
1647                                 if (printk_ratelimit())
1648                                         printk(KERN_ERR "md/raid1:%s: redirecting sector %llu to"
1649                                                " other mirror: %s\n",
1650                                                mdname(mddev),
1651                                                (unsigned long long)r1_bio->sector,
1652                                                bdevname(rdev->bdev,b));
1653                                 bio->bi_sector = r1_bio->sector + rdev->data_offset;
1654                                 bio->bi_bdev = rdev->bdev;
1655                                 bio->bi_end_io = raid1_end_read_request;
1656                                 bio->bi_rw = READ | do_sync;
1657                                 bio->bi_private = r1_bio;
1658                                 unplug = 1;
1659                                 generic_make_request(bio);
1660                         }
1661                 }
1662                 cond_resched();
1663         }
1664         if (unplug)
1665                 unplug_slaves(mddev);
1666 }
1667
1668
1669 static int init_resync(conf_t *conf)
1670 {
1671         int buffs;
1672
1673         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1674         BUG_ON(conf->r1buf_pool);
1675         conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
1676                                           conf->poolinfo);
1677         if (!conf->r1buf_pool)
1678                 return -ENOMEM;
1679         conf->next_resync = 0;
1680         return 0;
1681 }
1682
1683 /*
1684  * perform a "sync" on one "block"
1685  *
1686  * We need to make sure that no normal I/O request - particularly write
1687  * requests - conflict with active sync requests.
1688  *
1689  * This is achieved by tracking pending requests and a 'barrier' concept
1690  * that can be installed to exclude normal IO requests.
1691  */
1692
1693 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
1694 {
1695         conf_t *conf = mddev->private;
1696         r1bio_t *r1_bio;
1697         struct bio *bio;
1698         sector_t max_sector, nr_sectors;
1699         int disk = -1;
1700         int i;
1701         int wonly = -1;
1702         int write_targets = 0, read_targets = 0;
1703         sector_t sync_blocks;
1704         int still_degraded = 0;
1705
1706         if (!conf->r1buf_pool)
1707                 if (init_resync(conf))
1708                         return 0;
1709
1710         max_sector = mddev->dev_sectors;
1711         if (sector_nr >= max_sector) {
1712                 /* If we aborted, we need to abort the
1713                  * sync on the 'current' bitmap chunk (there will
1714                  * only be one in raid1 resync.
1715                  * We can find the current addess in mddev->curr_resync
1716                  */
1717                 if (mddev->curr_resync < max_sector) /* aborted */
1718                         bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1719                                                 &sync_blocks, 1);
1720                 else /* completed sync */
1721                         conf->fullsync = 0;
1722
1723                 bitmap_close_sync(mddev->bitmap);
1724                 close_sync(conf);
1725                 return 0;
1726         }
1727
1728         if (mddev->bitmap == NULL &&
1729             mddev->recovery_cp == MaxSector &&
1730             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
1731             conf->fullsync == 0) {
1732                 *skipped = 1;
1733                 return max_sector - sector_nr;
1734         }
1735         /* before building a request, check if we can skip these blocks..
1736          * This call the bitmap_start_sync doesn't actually record anything
1737          */
1738         if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
1739             !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1740                 /* We can skip this block, and probably several more */
1741                 *skipped = 1;
1742                 return sync_blocks;
1743         }
1744         /*
1745          * If there is non-resync activity waiting for a turn,
1746          * and resync is going fast enough,
1747          * then let it though before starting on this new sync request.
1748          */
1749         if (!go_faster && conf->nr_waiting)
1750                 msleep_interruptible(1000);
1751
1752         bitmap_cond_end_sync(mddev->bitmap, sector_nr);
1753         r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
1754         raise_barrier(conf);
1755
1756         conf->next_resync = sector_nr;
1757
1758         rcu_read_lock();
1759         /*
1760          * If we get a correctably read error during resync or recovery,
1761          * we might want to read from a different device.  So we
1762          * flag all drives that could conceivably be read from for READ,
1763          * and any others (which will be non-In_sync devices) for WRITE.
1764          * If a read fails, we try reading from something else for which READ
1765          * is OK.
1766          */
1767
1768         r1_bio->mddev = mddev;
1769         r1_bio->sector = sector_nr;
1770         r1_bio->state = 0;
1771         set_bit(R1BIO_IsSync, &r1_bio->state);
1772
1773         for (i=0; i < conf->raid_disks; i++) {
1774                 mdk_rdev_t *rdev;
1775                 bio = r1_bio->bios[i];
1776
1777                 /* take from bio_init */
1778                 bio->bi_next = NULL;
1779                 bio->bi_flags &= ~(BIO_POOL_MASK-1);
1780                 bio->bi_flags |= 1 << BIO_UPTODATE;
1781                 bio->bi_comp_cpu = -1;
1782                 bio->bi_rw = READ;
1783                 bio->bi_vcnt = 0;
1784                 bio->bi_idx = 0;
1785                 bio->bi_phys_segments = 0;
1786                 bio->bi_size = 0;
1787                 bio->bi_end_io = NULL;
1788                 bio->bi_private = NULL;
1789
1790                 rdev = rcu_dereference(conf->mirrors[i].rdev);
1791                 if (rdev == NULL ||
1792                            test_bit(Faulty, &rdev->flags)) {
1793                         still_degraded = 1;
1794                         continue;
1795                 } else if (!test_bit(In_sync, &rdev->flags)) {
1796                         bio->bi_rw = WRITE;
1797                         bio->bi_end_io = end_sync_write;
1798                         write_targets ++;
1799                 } else {
1800                         /* may need to read from here */
1801                         bio->bi_rw = READ;
1802                         bio->bi_end_io = end_sync_read;
1803                         if (test_bit(WriteMostly, &rdev->flags)) {
1804                                 if (wonly < 0)
1805                                         wonly = i;
1806                         } else {
1807                                 if (disk < 0)
1808                                         disk = i;
1809                         }
1810                         read_targets++;
1811                 }
1812                 atomic_inc(&rdev->nr_pending);
1813                 bio->bi_sector = sector_nr + rdev->data_offset;
1814                 bio->bi_bdev = rdev->bdev;
1815                 bio->bi_private = r1_bio;
1816         }
1817         rcu_read_unlock();
1818         if (disk < 0)
1819                 disk = wonly;
1820         r1_bio->read_disk = disk;
1821
1822         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
1823                 /* extra read targets are also write targets */
1824                 write_targets += read_targets-1;
1825
1826         if (write_targets == 0 || read_targets == 0) {
1827                 /* There is nowhere to write, so all non-sync
1828                  * drives must be failed - so we are finished
1829                  */
1830                 sector_t rv = max_sector - sector_nr;
1831                 *skipped = 1;
1832                 put_buf(r1_bio);
1833                 return rv;
1834         }
1835
1836         if (max_sector > mddev->resync_max)
1837                 max_sector = mddev->resync_max; /* Don't do IO beyond here */
1838         nr_sectors = 0;
1839         sync_blocks = 0;
1840         do {
1841                 struct page *page;
1842                 int len = PAGE_SIZE;
1843                 if (sector_nr + (len>>9) > max_sector)
1844                         len = (max_sector - sector_nr) << 9;
1845                 if (len == 0)
1846                         break;
1847                 if (sync_blocks == 0) {
1848                         if (!bitmap_start_sync(mddev->bitmap, sector_nr,
1849                                                &sync_blocks, still_degraded) &&
1850                             !conf->fullsync &&
1851                             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1852                                 break;
1853                         BUG_ON(sync_blocks < (PAGE_SIZE>>9));
1854                         if ((len >> 9) > sync_blocks)
1855                                 len = sync_blocks<<9;
1856                 }
1857
1858                 for (i=0 ; i < conf->raid_disks; i++) {
1859                         bio = r1_bio->bios[i];
1860                         if (bio->bi_end_io) {
1861                                 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
1862                                 if (bio_add_page(bio, page, len, 0) == 0) {
1863                                         /* stop here */
1864                                         bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
1865                                         while (i > 0) {
1866                                                 i--;
1867                                                 bio = r1_bio->bios[i];
1868                                                 if (bio->bi_end_io==NULL)
1869                                                         continue;
1870                                                 /* remove last page from this bio */
1871                                                 bio->bi_vcnt--;
1872                                                 bio->bi_size -= len;
1873                                                 bio->bi_flags &= ~(1<< BIO_SEG_VALID);
1874                                         }
1875                                         goto bio_full;
1876                                 }
1877                         }
1878                 }
1879                 nr_sectors += len>>9;
1880                 sector_nr += len>>9;
1881                 sync_blocks -= (len>>9);
1882         } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
1883  bio_full:
1884         r1_bio->sectors = nr_sectors;
1885
1886         /* For a user-requested sync, we read all readable devices and do a
1887          * compare
1888          */
1889         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1890                 atomic_set(&r1_bio->remaining, read_targets);
1891                 for (i=0; i<conf->raid_disks; i++) {
1892                         bio = r1_bio->bios[i];
1893                         if (bio->bi_end_io == end_sync_read) {
1894                                 md_sync_acct(bio->bi_bdev, nr_sectors);
1895                                 generic_make_request(bio);
1896                         }
1897                 }
1898         } else {
1899                 atomic_set(&r1_bio->remaining, 1);
1900                 bio = r1_bio->bios[r1_bio->read_disk];
1901                 md_sync_acct(bio->bi_bdev, nr_sectors);
1902                 generic_make_request(bio);
1903
1904         }
1905         return nr_sectors;
1906 }
1907
1908 static sector_t raid1_size(mddev_t *mddev, sector_t sectors, int raid_disks)
1909 {
1910         if (sectors)
1911                 return sectors;
1912
1913         return mddev->dev_sectors;
1914 }
1915
1916 static conf_t *setup_conf(mddev_t *mddev)
1917 {
1918         conf_t *conf;
1919         int i;
1920         mirror_info_t *disk;
1921         mdk_rdev_t *rdev;
1922         int err = -ENOMEM;
1923
1924         conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
1925         if (!conf)
1926                 goto abort;
1927
1928         conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
1929                                  GFP_KERNEL);
1930         if (!conf->mirrors)
1931                 goto abort;
1932
1933         conf->tmppage = alloc_page(GFP_KERNEL);
1934         if (!conf->tmppage)
1935                 goto abort;
1936
1937         conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
1938         if (!conf->poolinfo)
1939                 goto abort;
1940         conf->poolinfo->raid_disks = mddev->raid_disks;
1941         conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
1942                                           r1bio_pool_free,
1943                                           conf->poolinfo);
1944         if (!conf->r1bio_pool)
1945                 goto abort;
1946
1947         conf->poolinfo->mddev = mddev;
1948
1949         spin_lock_init(&conf->device_lock);
1950         list_for_each_entry(rdev, &mddev->disks, same_set) {
1951                 int disk_idx = rdev->raid_disk;
1952                 if (disk_idx >= mddev->raid_disks
1953                     || disk_idx < 0)
1954                         continue;
1955                 disk = conf->mirrors + disk_idx;
1956
1957                 disk->rdev = rdev;
1958
1959                 disk->head_position = 0;
1960         }
1961         conf->raid_disks = mddev->raid_disks;
1962         conf->mddev = mddev;
1963         INIT_LIST_HEAD(&conf->retry_list);
1964
1965         spin_lock_init(&conf->resync_lock);
1966         init_waitqueue_head(&conf->wait_barrier);
1967
1968         bio_list_init(&conf->pending_bio_list);
1969
1970         conf->last_used = -1;
1971         for (i = 0; i < conf->raid_disks; i++) {
1972
1973                 disk = conf->mirrors + i;
1974
1975                 if (!disk->rdev ||
1976                     !test_bit(In_sync, &disk->rdev->flags)) {
1977                         disk->head_position = 0;
1978                         if (disk->rdev)
1979                                 conf->fullsync = 1;
1980                 } else if (conf->last_used < 0)
1981                         /*
1982                          * The first working device is used as a
1983                          * starting point to read balancing.
1984                          */
1985                         conf->last_used = i;
1986         }
1987
1988         err = -EIO;
1989         if (conf->last_used < 0) {
1990                 printk(KERN_ERR "md/raid1:%s: no operational mirrors\n",
1991                        mdname(mddev));
1992                 goto abort;
1993         }
1994         err = -ENOMEM;
1995         conf->thread = md_register_thread(raid1d, mddev, NULL);
1996         if (!conf->thread) {
1997                 printk(KERN_ERR
1998                        "md/raid1:%s: couldn't allocate thread\n",
1999                        mdname(mddev));
2000                 goto abort;
2001         }
2002
2003         return conf;
2004
2005  abort:
2006         if (conf) {
2007                 if (conf->r1bio_pool)
2008                         mempool_destroy(conf->r1bio_pool);
2009                 kfree(conf->mirrors);
2010                 safe_put_page(conf->tmppage);
2011                 kfree(conf->poolinfo);
2012                 kfree(conf);
2013         }
2014         return ERR_PTR(err);
2015 }
2016
2017 static int run(mddev_t *mddev)
2018 {
2019         conf_t *conf;
2020         int i;
2021         mdk_rdev_t *rdev;
2022
2023         if (mddev->level != 1) {
2024                 printk(KERN_ERR "md/raid1:%s: raid level not set to mirroring (%d)\n",
2025                        mdname(mddev), mddev->level);
2026                 return -EIO;
2027         }
2028         if (mddev->reshape_position != MaxSector) {
2029                 printk(KERN_ERR "md/raid1:%s: reshape_position set but not supported\n",
2030                        mdname(mddev));
2031                 return -EIO;
2032         }
2033         /*
2034          * copy the already verified devices into our private RAID1
2035          * bookkeeping area. [whatever we allocate in run(),
2036          * should be freed in stop()]
2037          */
2038         if (mddev->private == NULL)
2039                 conf = setup_conf(mddev);
2040         else
2041                 conf = mddev->private;
2042
2043         if (IS_ERR(conf))
2044                 return PTR_ERR(conf);
2045
2046         mddev->queue->queue_lock = &conf->device_lock;
2047         list_for_each_entry(rdev, &mddev->disks, same_set) {
2048                 disk_stack_limits(mddev->gendisk, rdev->bdev,
2049                                   rdev->data_offset << 9);
2050                 /* as we don't honour merge_bvec_fn, we must never risk
2051                  * violating it, so limit ->max_segments to 1 lying within
2052                  * a single page, as a one page request is never in violation.
2053                  */
2054                 if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
2055                         blk_queue_max_segments(mddev->queue, 1);
2056                         blk_queue_segment_boundary(mddev->queue,
2057                                                    PAGE_CACHE_SIZE - 1);
2058                 }
2059         }
2060
2061         mddev->degraded = 0;
2062         for (i=0; i < conf->raid_disks; i++)
2063                 if (conf->mirrors[i].rdev == NULL ||
2064                     !test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
2065                     test_bit(Faulty, &conf->mirrors[i].rdev->flags))
2066                         mddev->degraded++;
2067
2068         if (conf->raid_disks - mddev->degraded == 1)
2069                 mddev->recovery_cp = MaxSector;
2070
2071         if (mddev->recovery_cp != MaxSector)
2072                 printk(KERN_NOTICE "md/raid1:%s: not clean"
2073                        " -- starting background reconstruction\n",
2074                        mdname(mddev));
2075         printk(KERN_INFO
2076                 "md/raid1:%s: active with %d out of %d mirrors\n",
2077                 mdname(mddev), mddev->raid_disks - mddev->degraded,
2078                 mddev->raid_disks);
2079
2080         /*
2081          * Ok, everything is just fine now
2082          */
2083         mddev->thread = conf->thread;
2084         conf->thread = NULL;
2085         mddev->private = conf;
2086
2087         md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
2088
2089         mddev->queue->unplug_fn = raid1_unplug;
2090         mddev->queue->backing_dev_info.congested_fn = raid1_congested;
2091         mddev->queue->backing_dev_info.congested_data = mddev;
2092         md_integrity_register(mddev);
2093         return 0;
2094 }
2095
2096 static int stop(mddev_t *mddev)
2097 {
2098         conf_t *conf = mddev->private;
2099         struct bitmap *bitmap = mddev->bitmap;
2100
2101         /* wait for behind writes to complete */
2102         if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
2103                 printk(KERN_INFO "md/raid1:%s: behind writes in progress - waiting to stop.\n",
2104                        mdname(mddev));
2105                 /* need to kick something here to make sure I/O goes? */
2106                 wait_event(bitmap->behind_wait,
2107                            atomic_read(&bitmap->behind_writes) == 0);
2108         }
2109
2110         raise_barrier(conf);
2111         lower_barrier(conf);
2112
2113         md_unregister_thread(mddev->thread);
2114         mddev->thread = NULL;
2115         blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
2116         if (conf->r1bio_pool)
2117                 mempool_destroy(conf->r1bio_pool);
2118         kfree(conf->mirrors);
2119         kfree(conf->poolinfo);
2120         kfree(conf);
2121         mddev->private = NULL;
2122         return 0;
2123 }
2124
2125 static int raid1_resize(mddev_t *mddev, sector_t sectors)
2126 {
2127         /* no resync is happening, and there is enough space
2128          * on all devices, so we can resize.
2129          * We need to make sure resync covers any new space.
2130          * If the array is shrinking we should possibly wait until
2131          * any io in the removed space completes, but it hardly seems
2132          * worth it.
2133          */
2134         md_set_array_sectors(mddev, raid1_size(mddev, sectors, 0));
2135         if (mddev->array_sectors > raid1_size(mddev, sectors, 0))
2136                 return -EINVAL;
2137         set_capacity(mddev->gendisk, mddev->array_sectors);
2138         revalidate_disk(mddev->gendisk);
2139         if (sectors > mddev->dev_sectors &&
2140             mddev->recovery_cp == MaxSector) {
2141                 mddev->recovery_cp = mddev->dev_sectors;
2142                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2143         }
2144         mddev->dev_sectors = sectors;
2145         mddev->resync_max_sectors = sectors;
2146         return 0;
2147 }
2148
2149 static int raid1_reshape(mddev_t *mddev)
2150 {
2151         /* We need to:
2152          * 1/ resize the r1bio_pool
2153          * 2/ resize conf->mirrors
2154          *
2155          * We allocate a new r1bio_pool if we can.
2156          * Then raise a device barrier and wait until all IO stops.
2157          * Then resize conf->mirrors and swap in the new r1bio pool.
2158          *
2159          * At the same time, we "pack" the devices so that all the missing
2160          * devices have the higher raid_disk numbers.
2161          */
2162         mempool_t *newpool, *oldpool;
2163         struct pool_info *newpoolinfo;
2164         mirror_info_t *newmirrors;
2165         conf_t *conf = mddev->private;
2166         int cnt, raid_disks;
2167         unsigned long flags;
2168         int d, d2, err;
2169
2170         /* Cannot change chunk_size, layout, or level */
2171         if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
2172             mddev->layout != mddev->new_layout ||
2173             mddev->level != mddev->new_level) {
2174                 mddev->new_chunk_sectors = mddev->chunk_sectors;
2175                 mddev->new_layout = mddev->layout;
2176                 mddev->new_level = mddev->level;
2177                 return -EINVAL;
2178         }
2179
2180         err = md_allow_write(mddev);
2181         if (err)
2182                 return err;
2183
2184         raid_disks = mddev->raid_disks + mddev->delta_disks;
2185
2186         if (raid_disks < conf->raid_disks) {
2187                 cnt=0;
2188                 for (d= 0; d < conf->raid_disks; d++)
2189                         if (conf->mirrors[d].rdev)
2190                                 cnt++;
2191                 if (cnt > raid_disks)
2192                         return -EBUSY;
2193         }
2194
2195         newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
2196         if (!newpoolinfo)
2197                 return -ENOMEM;
2198         newpoolinfo->mddev = mddev;
2199         newpoolinfo->raid_disks = raid_disks;
2200
2201         newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2202                                  r1bio_pool_free, newpoolinfo);
2203         if (!newpool) {
2204                 kfree(newpoolinfo);
2205                 return -ENOMEM;
2206         }
2207         newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
2208         if (!newmirrors) {
2209                 kfree(newpoolinfo);
2210                 mempool_destroy(newpool);
2211                 return -ENOMEM;
2212         }
2213
2214         raise_barrier(conf);
2215
2216         /* ok, everything is stopped */
2217         oldpool = conf->r1bio_pool;
2218         conf->r1bio_pool = newpool;
2219
2220         for (d = d2 = 0; d < conf->raid_disks; d++) {
2221                 mdk_rdev_t *rdev = conf->mirrors[d].rdev;
2222                 if (rdev && rdev->raid_disk != d2) {
2223                         char nm[20];
2224                         sprintf(nm, "rd%d", rdev->raid_disk);
2225                         sysfs_remove_link(&mddev->kobj, nm);
2226                         rdev->raid_disk = d2;
2227                         sprintf(nm, "rd%d", rdev->raid_disk);
2228                         sysfs_remove_link(&mddev->kobj, nm);
2229                         if (sysfs_create_link(&mddev->kobj,
2230                                               &rdev->kobj, nm))
2231                                 printk(KERN_WARNING
2232                                        "md/raid1:%s: cannot register "
2233                                        "%s\n",
2234                                        mdname(mddev), nm);
2235                 }
2236                 if (rdev)
2237                         newmirrors[d2++].rdev = rdev;
2238         }
2239         kfree(conf->mirrors);
2240         conf->mirrors = newmirrors;
2241         kfree(conf->poolinfo);
2242         conf->poolinfo = newpoolinfo;
2243
2244         spin_lock_irqsave(&conf->device_lock, flags);
2245         mddev->degraded += (raid_disks - conf->raid_disks);
2246         spin_unlock_irqrestore(&conf->device_lock, flags);
2247         conf->raid_disks = mddev->raid_disks = raid_disks;
2248         mddev->delta_disks = 0;
2249
2250         conf->last_used = 0; /* just make sure it is in-range */
2251         lower_barrier(conf);
2252
2253         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2254         md_wakeup_thread(mddev->thread);
2255
2256         mempool_destroy(oldpool);
2257         return 0;
2258 }
2259
2260 static void raid1_quiesce(mddev_t *mddev, int state)
2261 {
2262         conf_t *conf = mddev->private;
2263
2264         switch(state) {
2265         case 2: /* wake for suspend */
2266                 wake_up(&conf->wait_barrier);
2267                 break;
2268         case 1:
2269                 raise_barrier(conf);
2270                 break;
2271         case 0:
2272                 lower_barrier(conf);
2273                 break;
2274         }
2275 }
2276
2277 static void *raid1_takeover(mddev_t *mddev)
2278 {
2279         /* raid1 can take over:
2280          *  raid5 with 2 devices, any layout or chunk size
2281          */
2282         if (mddev->level == 5 && mddev->raid_disks == 2) {
2283                 conf_t *conf;
2284                 mddev->new_level = 1;
2285                 mddev->new_layout = 0;
2286                 mddev->new_chunk_sectors = 0;
2287                 conf = setup_conf(mddev);
2288                 if (!IS_ERR(conf))
2289                         conf->barrier = 1;
2290                 return conf;
2291         }
2292         return ERR_PTR(-EINVAL);
2293 }
2294
2295 static struct mdk_personality raid1_personality =
2296 {
2297         .name           = "raid1",
2298         .level          = 1,
2299         .owner          = THIS_MODULE,
2300         .make_request   = make_request,
2301         .run            = run,
2302         .stop           = stop,
2303         .status         = status,
2304         .error_handler  = error,
2305         .hot_add_disk   = raid1_add_disk,
2306         .hot_remove_disk= raid1_remove_disk,
2307         .spare_active   = raid1_spare_active,
2308         .sync_request   = sync_request,
2309         .resize         = raid1_resize,
2310         .size           = raid1_size,
2311         .check_reshape  = raid1_reshape,
2312         .quiesce        = raid1_quiesce,
2313         .takeover       = raid1_takeover,
2314 };
2315
2316 static int __init raid_init(void)
2317 {
2318         return register_md_personality(&raid1_personality);
2319 }
2320
2321 static void raid_exit(void)
2322 {
2323         unregister_md_personality(&raid1_personality);
2324 }
2325
2326 module_init(raid_init);
2327 module_exit(raid_exit);
2328 MODULE_LICENSE("GPL");
2329 MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
2330 MODULE_ALIAS("md-personality-3"); /* RAID1 */
2331 MODULE_ALIAS("md-raid1");
2332 MODULE_ALIAS("md-level-1");