drivers/md/raid1.c

   1 /*
   2  * raid1.c : Multiple Devices driver for Linux
   3  *
   4  * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat
   5  *
   6  * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman
   7  *
   8  * RAID-1 management functions.
   9  *
  10  * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000
  11  *
  12  * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
  13  * Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
  14  *
  15  * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support
  16  * bitmapped intelligence in resync:
  17  *
  18  *      - bitmap marked during normal i/o
  19  *      - bitmap used to skip nondirty blocks during sync
  20  *
  21  * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology:
  22  * - persistent bitmap code
  23  *
  24  * This program is free software; you can redistribute it and/or modify
  25  * it under the terms of the GNU General Public License as published by
  26  * the Free Software Foundation; either version 2, or (at your option)
  27  * any later version.
  28  *
  29  * You should have received a copy of the GNU General Public License
  30  * (for example /usr/src/linux/COPYING); if not, write to the Free
  31  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  32  */
  33
  34 #include <linux/slab.h>
  35 #include <linux/delay.h>
  36 #include <linux/blkdev.h>
  37 #include <linux/seq_file.h>
  38 #include <linux/ratelimit.h>
  39 #include "md.h"
  40 #include "raid1.h"
  41 #include "bitmap.h"
  42
  43 #define DEBUG 0
  44 #define PRINTK(x...) do { if (DEBUG) printk(x); } while (0)
  45
  46 /*
  47  * Number of guaranteed r1bios in case of extreme VM load:
  48  */
  49 #define NR_RAID1_BIOS 256
  50
  51
  52 static void allow_barrier(conf_t *conf);
  53 static void lower_barrier(conf_t *conf);
  54
  55 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
  56 {
  57         struct pool_info *pi = data;
  58         int size = offsetof(r1bio_t, bios[pi->raid_disks]);
  59
  60         /* allocate a r1bio with room for raid_disks entries in the bios array */
  61         return kzalloc(size, gfp_flags);
  62 }
  63
  64 static void r1bio_pool_free(void *r1_bio, void *data)
  65 {
  66         kfree(r1_bio);
  67 }
  68
  69 #define RESYNC_BLOCK_SIZE (64*1024)
  70 //#define RESYNC_BLOCK_SIZE PAGE_SIZE
  71 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
  72 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
  73 #define RESYNC_WINDOW (2048*1024)
  74
  75 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
  76 {
  77         struct pool_info *pi = data;
  78         struct page *page;
  79         r1bio_t *r1_bio;
  80         struct bio *bio;
  81         int i, j;
  82
  83         r1_bio = r1bio_pool_alloc(gfp_flags, pi);
  84         if (!r1_bio)
  85                 return NULL;
  86
  87         /*
  88          * Allocate bios : 1 for reading, n-1 for writing
  89          */
  90         for (j = pi->raid_disks ; j-- ; ) {
  91                 bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
  92                 if (!bio)
  93                         goto out_free_bio;
  94                 r1_bio->bios[j] = bio;
  95         }
  96         /*
  97          * Allocate RESYNC_PAGES data pages and attach them to
  98          * the first bio.
  99          * If this is a user-requested check/repair, allocate
 100          * RESYNC_PAGES for each bio.
 101          */
 102         if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
 103                 j = pi->raid_disks;
 104         else
 105                 j = 1;
 106         while(j--) {
 107                 bio = r1_bio->bios[j];
 108                 for (i = 0; i < RESYNC_PAGES; i++) {
 109                         page = alloc_page(gfp_flags);
 110                         if (unlikely(!page))
 111                                 goto out_free_pages;
 112
 113                         bio->bi_io_vec[i].bv_page = page;
 114                         bio->bi_vcnt = i+1;
 115                 }
 116         }
 117         /* If not user-requests, copy the page pointers to all bios */
 118         if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
 119                 for (i=0; i<RESYNC_PAGES ; i++)
 120                         for (j=1; j<pi->raid_disks; j++)
 121                                 r1_bio->bios[j]->bi_io_vec[i].bv_page =
 122                                         r1_bio->bios[0]->bi_io_vec[i].bv_page;
 123         }
 124
 125         r1_bio->master_bio = NULL;
 126
 127         return r1_bio;
 128
 129 out_free_pages:
 130         for (j=0 ; j < pi->raid_disks; j++)
 131                 for (i=0; i < r1_bio->bios[j]->bi_vcnt ; i++)
 132                         put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
 133         j = -1;
 134 out_free_bio:
 135         while ( ++j < pi->raid_disks )
 136                 bio_put(r1_bio->bios[j]);
 137         r1bio_pool_free(r1_bio, data);
 138         return NULL;
 139 }
 140
 141 static void r1buf_pool_free(void *__r1_bio, void *data)
 142 {
 143         struct pool_info *pi = data;
 144         int i,j;
 145         r1bio_t *r1bio = __r1_bio;
 146
 147         for (i = 0; i < RESYNC_PAGES; i++)
 148                 for (j = pi->raid_disks; j-- ;) {
 149                         if (j == 0 ||
 150                             r1bio->bios[j]->bi_io_vec[i].bv_page !=
 151                             r1bio->bios[0]->bi_io_vec[i].bv_page)
 152                                 safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page);
 153                 }
 154         for (i=0 ; i < pi->raid_disks; i++)
 155                 bio_put(r1bio->bios[i]);
 156
 157         r1bio_pool_free(r1bio, data);
 158 }
 159
 160 static void put_all_bios(conf_t *conf, r1bio_t *r1_bio)
 161 {
 162         int i;
 163
 164         for (i = 0; i < conf->raid_disks; i++) {
 165                 struct bio **bio = r1_bio->bios + i;
 166                 if (*bio && *bio != IO_BLOCKED)
 167                         bio_put(*bio);
 168                 *bio = NULL;
 169         }
 170 }
 171
 172 static void free_r1bio(r1bio_t *r1_bio)
 173 {
 174         conf_t *conf = r1_bio->mddev->private;
 175
 176         put_all_bios(conf, r1_bio);
 177         mempool_free(r1_bio, conf->r1bio_pool);
 178 }
 179
 180 static void put_buf(r1bio_t *r1_bio)
 181 {
 182         conf_t *conf = r1_bio->mddev->private;
 183         int i;
 184
 185         for (i=0; i<conf->raid_disks; i++) {
 186                 struct bio *bio = r1_bio->bios[i];
 187                 if (bio->bi_end_io)
 188                         rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
 189         }
 190
 191         mempool_free(r1_bio, conf->r1buf_pool);
 192
 193         lower_barrier(conf);
 194 }
 195
 196 static void reschedule_retry(r1bio_t *r1_bio)
 197 {
 198         unsigned long flags;
 199         mddev_t *mddev = r1_bio->mddev;
 200         conf_t *conf = mddev->private;
 201
 202         spin_lock_irqsave(&conf->device_lock, flags);
 203         list_add(&r1_bio->retry_list, &conf->retry_list);
 204         conf->nr_queued ++;
 205         spin_unlock_irqrestore(&conf->device_lock, flags);
 206
 207         wake_up(&conf->wait_barrier);
 208         md_wakeup_thread(mddev->thread);
 209 }
 210
 211 /*
 212  * raid_end_bio_io() is called when we have finished servicing a mirrored
 213  * operation and are ready to return a success/failure code to the buffer
 214  * cache layer.
 215  */
 216 static void call_bio_endio(r1bio_t *r1_bio)
 217 {
 218         struct bio *bio = r1_bio->master_bio;
 219         int done;
 220         conf_t *conf = r1_bio->mddev->private;
 221
 222         if (bio->bi_phys_segments) {
 223                 unsigned long flags;
 224                 spin_lock_irqsave(&conf->device_lock, flags);
 225                 bio->bi_phys_segments--;
 226                 done = (bio->bi_phys_segments == 0);
 227                 spin_unlock_irqrestore(&conf->device_lock, flags);
 228         } else
 229                 done = 1;
 230
 231         if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
 232                 clear_bit(BIO_UPTODATE, &bio->bi_flags);
 233         if (done) {
 234                 bio_endio(bio, 0);
 235                 /*
 236                  * Wake up any possible resync thread that waits for the device
 237                  * to go idle.
 238                  */
 239                 allow_barrier(conf);
 240         }
 241 }
 242
 243 static void raid_end_bio_io(r1bio_t *r1_bio)
 244 {
 245         struct bio *bio = r1_bio->master_bio;
 246
 247         /* if nobody has done the final endio yet, do it now */
 248         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 249                 PRINTK(KERN_DEBUG "raid1: sync end %s on sectors %llu-%llu\n",
 250                         (bio_data_dir(bio) == WRITE) ? "write" : "read",
 251                         (unsigned long long) bio->bi_sector,
 252                         (unsigned long long) bio->bi_sector +
 253                                 (bio->bi_size >> 9) - 1);
 254
 255                 call_bio_endio(r1_bio);
 256         }
 257         free_r1bio(r1_bio);
 258 }
 259
 260 /*
 261  * Update disk head position estimator based on IRQ completion info.
 262  */
 263 static inline void update_head_pos(int disk, r1bio_t *r1_bio)
 264 {
 265         conf_t *conf = r1_bio->mddev->private;
 266
 267         conf->mirrors[disk].head_position =
 268                 r1_bio->sector + (r1_bio->sectors);
 269 }
 270
 271 static void raid1_end_read_request(struct bio *bio, int error)
 272 {
 273         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 274         r1bio_t *r1_bio = bio->bi_private;
 275         int mirror;
 276         conf_t *conf = r1_bio->mddev->private;
 277
 278         mirror = r1_bio->read_disk;
 279         /*
 280          * this branch is our 'one mirror IO has finished' event handler:
 281          */
 282         update_head_pos(mirror, r1_bio);
 283
 284         if (uptodate)
 285                 set_bit(R1BIO_Uptodate, &r1_bio->state);
 286         else {
 287                 /* If all other devices have failed, we want to return
 288                  * the error upwards rather than fail the last device.
 289                  * Here we redefine "uptodate" to mean "Don't want to retry"
 290                  */
 291                 unsigned long flags;
 292                 spin_lock_irqsave(&conf->device_lock, flags);
 293                 if (r1_bio->mddev->degraded == conf->raid_disks ||
 294                     (r1_bio->mddev->degraded == conf->raid_disks-1 &&
 295                      !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags)))
 296                         uptodate = 1;
 297                 spin_unlock_irqrestore(&conf->device_lock, flags);
 298         }
 299
 300         if (uptodate)
 301                 raid_end_bio_io(r1_bio);
 302         else {
 303                 /*
 304                  * oops, read error:
 305                  */
 306                 char b[BDEVNAME_SIZE];
 307                 printk_ratelimited(
 308                         KERN_ERR "md/raid1:%s: %s: "
 309                         "rescheduling sector %llu\n",
 310                         mdname(conf->mddev),
 311                         bdevname(conf->mirrors[mirror].rdev->bdev,
 312                                  b),
 313                         (unsigned long long)r1_bio->sector);
 314                 set_bit(R1BIO_ReadError, &r1_bio->state);
 315                 reschedule_retry(r1_bio);
 316         }
 317
 318         rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
 319 }
 320
 321 static void r1_bio_write_done(r1bio_t *r1_bio)
 322 {
 323         if (atomic_dec_and_test(&r1_bio->remaining))
 324         {
 325                 /* it really is the end of this request */
 326                 if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
 327                         /* free extra copy of the data pages */
 328                         int i = r1_bio->behind_page_count;
 329                         while (i--)
 330                                 safe_put_page(r1_bio->behind_pages[i]);
 331                         kfree(r1_bio->behind_pages);
 332                         r1_bio->behind_pages = NULL;
 333                 }
 334                 /* clear the bitmap if all writes complete successfully */
 335                 bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
 336                                 r1_bio->sectors,
 337                                 !test_bit(R1BIO_Degraded, &r1_bio->state),
 338                                 test_bit(R1BIO_BehindIO, &r1_bio->state));
 339                 md_write_end(r1_bio->mddev);
 340                 raid_end_bio_io(r1_bio);
 341         }
 342 }
 343
 344 static void raid1_end_write_request(struct bio *bio, int error)
 345 {
 346         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 347         r1bio_t *r1_bio = bio->bi_private;
 348         int mirror, behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
 349         conf_t *conf = r1_bio->mddev->private;
 350         struct bio *to_put = NULL;
 351
 352
 353         for (mirror = 0; mirror < conf->raid_disks; mirror++)
 354                 if (r1_bio->bios[mirror] == bio)
 355                         break;
 356
 357         /*
 358          * 'one mirror IO has finished' event handler:
 359          */
 360         r1_bio->bios[mirror] = NULL;
 361         to_put = bio;
 362         if (!uptodate) {
 363                 md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
 364                 /* an I/O failed, we can't clear the bitmap */
 365                 set_bit(R1BIO_Degraded, &r1_bio->state);
 366         } else
 367                 /*
 368                  * Set R1BIO_Uptodate in our master bio, so that we
 369                  * will return a good error code for to the higher
 370                  * levels even if IO on some other mirrored buffer
 371                  * fails.
 372                  *
 373                  * The 'master' represents the composite IO operation
 374                  * to user-side. So if something waits for IO, then it
 375                  * will wait for the 'master' bio.
 376                  */
 377                 set_bit(R1BIO_Uptodate, &r1_bio->state);
 378
 379         update_head_pos(mirror, r1_bio);
 380
 381         if (behind) {
 382                 if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags))
 383                         atomic_dec(&r1_bio->behind_remaining);
 384
 385                 /*
 386                  * In behind mode, we ACK the master bio once the I/O
 387                  * has safely reached all non-writemostly
 388                  * disks. Setting the Returned bit ensures that this
 389                  * gets done only once -- we don't ever want to return
 390                  * -EIO here, instead we'll wait
 391                  */
 392                 if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
 393                     test_bit(R1BIO_Uptodate, &r1_bio->state)) {
 394                         /* Maybe we can return now */
 395                         if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
 396                                 struct bio *mbio = r1_bio->master_bio;
 397                                 PRINTK(KERN_DEBUG "raid1: behind end write sectors %llu-%llu\n",
 398                                        (unsigned long long) mbio->bi_sector,
 399                                        (unsigned long long) mbio->bi_sector +
 400                                        (mbio->bi_size >> 9) - 1);
 401                                 call_bio_endio(r1_bio);
 402                         }
 403                 }
 404         }
 405         rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
 406
 407         /*
 408          * Let's see if all mirrored write operations have finished
 409          * already.
 410          */
 411         r1_bio_write_done(r1_bio);
 412
 413         if (to_put)
 414                 bio_put(to_put);
 415 }
 416
 417
 418 /*
 419  * This routine returns the disk from which the requested read should
 420  * be done. There is a per-array 'next expected sequential IO' sector
 421  * number - if this matches on the next IO then we use the last disk.
 422  * There is also a per-disk 'last know head position' sector that is
 423  * maintained from IRQ contexts, both the normal and the resync IO
 424  * completion handlers update this position correctly. If there is no
 425  * perfect sequential match then we pick the disk whose head is closest.
 426  *
 427  * If there are 2 mirrors in the same 2 devices, performance degrades
 428  * because position is mirror, not device based.
 429  *
 430  * The rdev for the device selected will have nr_pending incremented.
 431  */
 432 static int read_balance(conf_t *conf, r1bio_t *r1_bio, int *max_sectors)
 433 {
 434         const sector_t this_sector = r1_bio->sector;
 435         int sectors;
 436         int best_good_sectors;
 437         int start_disk;
 438         int best_disk;
 439         int i;
 440         sector_t best_dist;
 441         mdk_rdev_t *rdev;
 442         int choose_first;
 443
 444         rcu_read_lock();
 445         /*
 446          * Check if we can balance. We can balance on the whole
 447          * device if no resync is going on, or below the resync window.
 448          * We take the first readable disk when above the resync window.
 449          */
 450  retry:
 451         sectors = r1_bio->sectors;
 452         best_disk = -1;
 453         best_dist = MaxSector;
 454         best_good_sectors = 0;
 455
 456         if (conf->mddev->recovery_cp < MaxSector &&
 457             (this_sector + sectors >= conf->next_resync)) {
 458                 choose_first = 1;
 459                 start_disk = 0;
 460         } else {
 461                 choose_first = 0;
 462                 start_disk = conf->last_used;
 463         }
 464
 465         for (i = 0 ; i < conf->raid_disks ; i++) {
 466                 sector_t dist;
 467                 sector_t first_bad;
 468                 int bad_sectors;
 469
 470                 int disk = start_disk + i;
 471                 if (disk >= conf->raid_disks)
 472                         disk -= conf->raid_disks;
 473
 474                 rdev = rcu_dereference(conf->mirrors[disk].rdev);
 475                 if (r1_bio->bios[disk] == IO_BLOCKED
 476                     || rdev == NULL
 477                     || test_bit(Faulty, &rdev->flags))
 478                         continue;
 479                 if (!test_bit(In_sync, &rdev->flags) &&
 480                     rdev->recovery_offset < this_sector + sectors)
 481                         continue;
 482                 if (test_bit(WriteMostly, &rdev->flags)) {
 483                         /* Don't balance among write-mostly, just
 484                          * use the first as a last resort */
 485                         if (best_disk < 0)
 486                                 best_disk = disk;
 487                         continue;
 488                 }
 489                 /* This is a reasonable device to use.  It might
 490                  * even be best.
 491                  */
 492                 if (is_badblock(rdev, this_sector, sectors,
 493                                 &first_bad, &bad_sectors)) {
 494                         if (best_dist < MaxSector)
 495                                 /* already have a better device */
 496                                 continue;
 497                         if (first_bad <= this_sector) {
 498                                 /* cannot read here. If this is the 'primary'
 499                                  * device, then we must not read beyond
 500                                  * bad_sectors from another device..
 501                                  */
 502                                 bad_sectors -= (this_sector - first_bad);
 503                                 if (choose_first && sectors > bad_sectors)
 504                                         sectors = bad_sectors;
 505                                 if (best_good_sectors > sectors)
 506                                         best_good_sectors = sectors;
 507
 508                         } else {
 509                                 sector_t good_sectors = first_bad - this_sector;
 510                                 if (good_sectors > best_good_sectors) {
 511                                         best_good_sectors = good_sectors;
 512                                         best_disk = disk;
 513                                 }
 514                                 if (choose_first)
 515                                         break;
 516                         }
 517                         continue;
 518                 } else
 519                         best_good_sectors = sectors;
 520
 521                 dist = abs(this_sector - conf->mirrors[disk].head_position);
 522                 if (choose_first
 523                     /* Don't change to another disk for sequential reads */
 524                     || conf->next_seq_sect == this_sector
 525                     || dist == 0
 526                     /* If device is idle, use it */
 527                     || atomic_read(&rdev->nr_pending) == 0) {
 528                         best_disk = disk;
 529                         break;
 530                 }
 531                 if (dist < best_dist) {
 532                         best_dist = dist;
 533                         best_disk = disk;
 534                 }
 535         }
 536
 537         if (best_disk >= 0) {
 538                 rdev = rcu_dereference(conf->mirrors[best_disk].rdev);
 539                 if (!rdev)
 540                         goto retry;
 541                 atomic_inc(&rdev->nr_pending);
 542                 if (test_bit(Faulty, &rdev->flags)) {
 543                         /* cannot risk returning a device that failed
 544                          * before we inc'ed nr_pending
 545                          */
 546                         rdev_dec_pending(rdev, conf->mddev);
 547                         goto retry;
 548                 }
 549                 sectors = best_good_sectors;
 550                 conf->next_seq_sect = this_sector + sectors;
 551                 conf->last_used = best_disk;
 552         }
 553         rcu_read_unlock();
 554         *max_sectors = sectors;
 555
 556         return best_disk;
 557 }
 558
 559 int md_raid1_congested(mddev_t *mddev, int bits)
 560 {
 561         conf_t *conf = mddev->private;
 562         int i, ret = 0;
 563
 564         rcu_read_lock();
 565         for (i = 0; i < mddev->raid_disks; i++) {
 566                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
 567                 if (rdev && !test_bit(Faulty, &rdev->flags)) {
 568                         struct request_queue *q = bdev_get_queue(rdev->bdev);
 569
 570                         BUG_ON(!q);
 571
 572                         /* Note the '|| 1' - when read_balance prefers
 573                          * non-congested targets, it can be removed
 574                          */
 575                         if ((bits & (1<<BDI_async_congested)) || 1)
 576                                 ret |= bdi_congested(&q->backing_dev_info, bits);
 577                         else
 578                                 ret &= bdi_congested(&q->backing_dev_info, bits);
 579                 }
 580         }
 581         rcu_read_unlock();
 582         return ret;
 583 }
 584 EXPORT_SYMBOL_GPL(md_raid1_congested);
 585
 586 static int raid1_congested(void *data, int bits)
 587 {
 588         mddev_t *mddev = data;
 589
 590         return mddev_congested(mddev, bits) ||
 591                 md_raid1_congested(mddev, bits);
 592 }
 593
 594 static void flush_pending_writes(conf_t *conf)
 595 {
 596         /* Any writes that have been queued but are awaiting
 597          * bitmap updates get flushed here.
 598          */
 599         spin_lock_irq(&conf->device_lock);
 600
 601         if (conf->pending_bio_list.head) {
 602                 struct bio *bio;
 603                 bio = bio_list_get(&conf->pending_bio_list);
 604                 spin_unlock_irq(&conf->device_lock);
 605                 /* flush any pending bitmap writes to
 606                  * disk before proceeding w/ I/O */
 607                 bitmap_unplug(conf->mddev->bitmap);
 608
 609                 while (bio) { /* submit pending writes */
 610                         struct bio *next = bio->bi_next;
 611                         bio->bi_next = NULL;
 612                         generic_make_request(bio);
 613                         bio = next;
 614                 }
 615         } else
 616                 spin_unlock_irq(&conf->device_lock);
 617 }
 618
 619 /* Barriers....
 620  * Sometimes we need to suspend IO while we do something else,
 621  * either some resync/recovery, or reconfigure the array.
 622  * To do this we raise a 'barrier'.
 623  * The 'barrier' is a counter that can be raised multiple times
 624  * to count how many activities are happening which preclude
 625  * normal IO.
 626  * We can only raise the barrier if there is no pending IO.
 627  * i.e. if nr_pending == 0.
 628  * We choose only to raise the barrier if no-one is waiting for the
 629  * barrier to go down.  This means that as soon as an IO request
 630  * is ready, no other operations which require a barrier will start
 631  * until the IO request has had a chance.
 632  *
 633  * So: regular IO calls 'wait_barrier'.  When that returns there
 634  *    is no backgroup IO happening,  It must arrange to call
 635  *    allow_barrier when it has finished its IO.
 636  * backgroup IO calls must call raise_barrier.  Once that returns
 637  *    there is no normal IO happeing.  It must arrange to call
 638  *    lower_barrier when the particular background IO completes.
 639  */
 640 #define RESYNC_DEPTH 32
 641
 642 static void raise_barrier(conf_t *conf)
 643 {
 644         spin_lock_irq(&conf->resync_lock);
 645
 646         /* Wait until no block IO is waiting */
 647         wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
 648                             conf->resync_lock, );
 649
 650         /* block any new IO from starting */
 651         conf->barrier++;
 652
 653         /* Now wait for all pending IO to complete */
 654         wait_event_lock_irq(conf->wait_barrier,
 655                             !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
 656                             conf->resync_lock, );
 657
 658         spin_unlock_irq(&conf->resync_lock);
 659 }
 660
 661 static void lower_barrier(conf_t *conf)
 662 {
 663         unsigned long flags;
 664         BUG_ON(conf->barrier <= 0);
 665         spin_lock_irqsave(&conf->resync_lock, flags);
 666         conf->barrier--;
 667         spin_unlock_irqrestore(&conf->resync_lock, flags);
 668         wake_up(&conf->wait_barrier);
 669 }
 670
 671 static void wait_barrier(conf_t *conf)
 672 {
 673         spin_lock_irq(&conf->resync_lock);
 674         if (conf->barrier) {
 675                 conf->nr_waiting++;
 676                 wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
 677                                     conf->resync_lock,
 678                                     );
 679                 conf->nr_waiting--;
 680         }
 681         conf->nr_pending++;
 682         spin_unlock_irq(&conf->resync_lock);
 683 }
 684
 685 static void allow_barrier(conf_t *conf)
 686 {
 687         unsigned long flags;
 688         spin_lock_irqsave(&conf->resync_lock, flags);
 689         conf->nr_pending--;
 690         spin_unlock_irqrestore(&conf->resync_lock, flags);
 691         wake_up(&conf->wait_barrier);
 692 }
 693
 694 static void freeze_array(conf_t *conf)
 695 {
 696         /* stop syncio and normal IO and wait for everything to
 697          * go quite.
 698          * We increment barrier and nr_waiting, and then
 699          * wait until nr_pending match nr_queued+1
 700          * This is called in the context of one normal IO request
 701          * that has failed. Thus any sync request that might be pending
 702          * will be blocked by nr_pending, and we need to wait for
 703          * pending IO requests to complete or be queued for re-try.
 704          * Thus the number queued (nr_queued) plus this request (1)
 705          * must match the number of pending IOs (nr_pending) before
 706          * we continue.
 707          */
 708         spin_lock_irq(&conf->resync_lock);
 709         conf->barrier++;
 710         conf->nr_waiting++;
 711         wait_event_lock_irq(conf->wait_barrier,
 712                             conf->nr_pending == conf->nr_queued+1,
 713                             conf->resync_lock,
 714                             flush_pending_writes(conf));
 715         spin_unlock_irq(&conf->resync_lock);
 716 }
 717 static void unfreeze_array(conf_t *conf)
 718 {
 719         /* reverse the effect of the freeze */
 720         spin_lock_irq(&conf->resync_lock);
 721         conf->barrier--;
 722         conf->nr_waiting--;
 723         wake_up(&conf->wait_barrier);
 724         spin_unlock_irq(&conf->resync_lock);
 725 }
 726
 727
 728 /* duplicate the data pages for behind I/O
 729  */
 730 static void alloc_behind_pages(struct bio *bio, r1bio_t *r1_bio)
 731 {
 732         int i;
 733         struct bio_vec *bvec;
 734         struct page **pages = kzalloc(bio->bi_vcnt * sizeof(struct page*),
 735                                         GFP_NOIO);
 736         if (unlikely(!pages))
 737                 return;
 738
 739         bio_for_each_segment(bvec, bio, i) {
 740                 pages[i] = alloc_page(GFP_NOIO);
 741                 if (unlikely(!pages[i]))
 742                         goto do_sync_io;
 743                 memcpy(kmap(pages[i]) + bvec->bv_offset,
 744                         kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
 745                 kunmap(pages[i]);
 746                 kunmap(bvec->bv_page);
 747         }
 748         r1_bio->behind_pages = pages;
 749         r1_bio->behind_page_count = bio->bi_vcnt;
 750         set_bit(R1BIO_BehindIO, &r1_bio->state);
 751         return;
 752
 753 do_sync_io:
 754         for (i = 0; i < bio->bi_vcnt; i++)
 755                 if (pages[i])
 756                         put_page(pages[i]);
 757         kfree(pages);
 758         PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
 759 }
 760
 761 static int make_request(mddev_t *mddev, struct bio * bio)
 762 {
 763         conf_t *conf = mddev->private;
 764         mirror_info_t *mirror;
 765         r1bio_t *r1_bio;
 766         struct bio *read_bio;
 767         int i, targets = 0, disks;
 768         struct bitmap *bitmap;
 769         unsigned long flags;
 770         const int rw = bio_data_dir(bio);
 771         const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
 772         const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA));
 773         mdk_rdev_t *blocked_rdev;
 774         int plugged;
 775
 776         /*
 777          * Register the new request and wait if the reconstruction
 778          * thread has put up a bar for new requests.
 779          * Continue immediately if no resync is active currently.
 780          */
 781
 782         md_write_start(mddev, bio); /* wait on superblock update early */
 783
 784         if (bio_data_dir(bio) == WRITE &&
 785             bio->bi_sector + bio->bi_size/512 > mddev->suspend_lo &&
 786             bio->bi_sector < mddev->suspend_hi) {
 787                 /* As the suspend_* range is controlled by
 788                  * userspace, we want an interruptible
 789                  * wait.
 790                  */
 791                 DEFINE_WAIT(w);
 792                 for (;;) {
 793                         flush_signals(current);
 794                         prepare_to_wait(&conf->wait_barrier,
 795                                         &w, TASK_INTERRUPTIBLE);
 796                         if (bio->bi_sector + bio->bi_size/512 <= mddev->suspend_lo ||
 797                             bio->bi_sector >= mddev->suspend_hi)
 798                                 break;
 799                         schedule();
 800                 }
 801                 finish_wait(&conf->wait_barrier, &w);
 802         }
 803
 804         wait_barrier(conf);
 805
 806         bitmap = mddev->bitmap;
 807
 808         /*
 809          * make_request() can abort the operation when READA is being
 810          * used and no empty request is available.
 811          *
 812          */
 813         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
 814
 815         r1_bio->master_bio = bio;
 816         r1_bio->sectors = bio->bi_size >> 9;
 817         r1_bio->state = 0;
 818         r1_bio->mddev = mddev;
 819         r1_bio->sector = bio->bi_sector;
 820
 821         /* We might need to issue multiple reads to different
 822          * devices if there are bad blocks around, so we keep
 823          * track of the number of reads in bio->bi_phys_segments.
 824          * If this is 0, there is only one r1_bio and no locking
 825          * will be needed when requests complete.  If it is
 826          * non-zero, then it is the number of not-completed requests.
 827          */
 828         bio->bi_phys_segments = 0;
 829         clear_bit(BIO_SEG_VALID, &bio->bi_flags);
 830
 831         if (rw == READ) {
 832                 /*
 833                  * read balancing logic:
 834                  */
 835                 int max_sectors;
 836                 int rdisk;
 837
 838 read_again:
 839                 rdisk = read_balance(conf, r1_bio, &max_sectors);
 840
 841                 if (rdisk < 0) {
 842                         /* couldn't find anywhere to read from */
 843                         raid_end_bio_io(r1_bio);
 844                         return 0;
 845                 }
 846                 mirror = conf->mirrors + rdisk;
 847
 848                 if (test_bit(WriteMostly, &mirror->rdev->flags) &&
 849                     bitmap) {
 850                         /* Reading from a write-mostly device must
 851                          * take care not to over-take any writes
 852                          * that are 'behind'
 853                          */
 854                         wait_event(bitmap->behind_wait,
 855                                    atomic_read(&bitmap->behind_writes) == 0);
 856                 }
 857                 r1_bio->read_disk = rdisk;
 858
 859                 read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
 860                 md_trim_bio(read_bio, r1_bio->sector - bio->bi_sector,
 861                             max_sectors);
 862
 863                 r1_bio->bios[rdisk] = read_bio;
 864
 865                 read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
 866                 read_bio->bi_bdev = mirror->rdev->bdev;
 867                 read_bio->bi_end_io = raid1_end_read_request;
 868                 read_bio->bi_rw = READ | do_sync;
 869                 read_bio->bi_private = r1_bio;
 870
 871                 if (max_sectors < r1_bio->sectors) {
 872                         /* could not read all from this device, so we will
 873                          * need another r1_bio.
 874                          */
 875                         int sectors_handled;
 876
 877                         sectors_handled = (r1_bio->sector + max_sectors
 878                                            - bio->bi_sector);
 879                         r1_bio->sectors = max_sectors;
 880                         spin_lock_irq(&conf->device_lock);
 881                         if (bio->bi_phys_segments == 0)
 882                                 bio->bi_phys_segments = 2;
 883                         else
 884                                 bio->bi_phys_segments++;
 885                         spin_unlock_irq(&conf->device_lock);
 886                         /* Cannot call generic_make_request directly
 887                          * as that will be queued in __make_request
 888                          * and subsequent mempool_alloc might block waiting
 889                          * for it.  So hand bio over to raid1d.
 890                          */
 891                         reschedule_retry(r1_bio);
 892
 893                         r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
 894
 895                         r1_bio->master_bio = bio;
 896                         r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
 897                         r1_bio->state = 0;
 898                         r1_bio->mddev = mddev;
 899                         r1_bio->sector = bio->bi_sector + sectors_handled;
 900                         goto read_again;
 901                 } else
 902                         generic_make_request(read_bio);
 903                 return 0;
 904         }
 905
 906         /*
 907          * WRITE:
 908          */
 909         /* first select target devices under spinlock and
 910          * inc refcount on their rdev.  Record them by setting
 911          * bios[x] to bio
 912          */
 913         plugged = mddev_check_plugged(mddev);
 914
 915         disks = conf->raid_disks;
 916  retry_write:
 917         blocked_rdev = NULL;
 918         rcu_read_lock();
 919         for (i = 0;  i < disks; i++) {
 920                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
 921                 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
 922                         atomic_inc(&rdev->nr_pending);
 923                         blocked_rdev = rdev;
 924                         break;
 925                 }
 926                 if (rdev && !test_bit(Faulty, &rdev->flags)) {
 927                         atomic_inc(&rdev->nr_pending);
 928                         if (test_bit(Faulty, &rdev->flags)) {
 929                                 rdev_dec_pending(rdev, mddev);
 930                                 r1_bio->bios[i] = NULL;
 931                         } else {
 932                                 r1_bio->bios[i] = bio;
 933                                 targets++;
 934                         }
 935                 } else
 936                         r1_bio->bios[i] = NULL;
 937         }
 938         rcu_read_unlock();
 939
 940         if (unlikely(blocked_rdev)) {
 941                 /* Wait for this device to become unblocked */
 942                 int j;
 943
 944                 for (j = 0; j < i; j++)
 945                         if (r1_bio->bios[j])
 946                                 rdev_dec_pending(conf->mirrors[j].rdev, mddev);
 947
 948                 allow_barrier(conf);
 949                 md_wait_for_blocked_rdev(blocked_rdev, mddev);
 950                 wait_barrier(conf);
 951                 goto retry_write;
 952         }
 953
 954         if (targets < conf->raid_disks) {
 955                 /* array is degraded, we will not clear the bitmap
 956                  * on I/O completion (see raid1_end_write_request) */
 957                 set_bit(R1BIO_Degraded, &r1_bio->state);
 958         }
 959
 960         /* do behind I/O ?
 961          * Not if there are too many, or cannot allocate memory,
 962          * or a reader on WriteMostly is waiting for behind writes
 963          * to flush */
 964         if (bitmap &&
 965             (atomic_read(&bitmap->behind_writes)
 966              < mddev->bitmap_info.max_write_behind) &&
 967             !waitqueue_active(&bitmap->behind_wait))
 968                 alloc_behind_pages(bio, r1_bio);
 969
 970         atomic_set(&r1_bio->remaining, 1);
 971         atomic_set(&r1_bio->behind_remaining, 0);
 972
 973         bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors,
 974                                 test_bit(R1BIO_BehindIO, &r1_bio->state));
 975         for (i = 0; i < disks; i++) {
 976                 struct bio *mbio;
 977                 if (!r1_bio->bios[i])
 978                         continue;
 979
 980                 mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
 981                 r1_bio->bios[i] = mbio;
 982
 983                 mbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset;
 984                 mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
 985                 mbio->bi_end_io = raid1_end_write_request;
 986                 mbio->bi_rw = WRITE | do_flush_fua | do_sync;
 987                 mbio->bi_private = r1_bio;
 988
 989                 if (r1_bio->behind_pages) {
 990                         struct bio_vec *bvec;
 991                         int j;
 992
 993                         /* Yes, I really want the '__' version so that
 994                          * we clear any unused pointer in the io_vec, rather
 995                          * than leave them unchanged.  This is important
 996                          * because when we come to free the pages, we won't
 997                          * know the original bi_idx, so we just free
 998                          * them all
 999                          */
1000                         __bio_for_each_segment(bvec, mbio, j, 0)
1001                                 bvec->bv_page = r1_bio->behind_pages[j];
1002                         if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
1003                                 atomic_inc(&r1_bio->behind_remaining);
1004                 }
1005
1006                 atomic_inc(&r1_bio->remaining);
1007                 spin_lock_irqsave(&conf->device_lock, flags);
1008                 bio_list_add(&conf->pending_bio_list, mbio);
1009                 spin_unlock_irqrestore(&conf->device_lock, flags);
1010         }
1011         r1_bio_write_done(r1_bio);
1012
1013         /* In case raid1d snuck in to freeze_array */
1014         wake_up(&conf->wait_barrier);
1015
1016         if (do_sync || !bitmap || !plugged)
1017                 md_wakeup_thread(mddev->thread);
1018
1019         return 0;
1020 }
1021
1022 static void status(struct seq_file *seq, mddev_t *mddev)
1023 {
1024         conf_t *conf = mddev->private;
1025         int i;
1026
1027         seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1028                    conf->raid_disks - mddev->degraded);
1029         rcu_read_lock();
1030         for (i = 0; i < conf->raid_disks; i++) {
1031                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1032                 seq_printf(seq, "%s",
1033                            rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1034         }
1035         rcu_read_unlock();
1036         seq_printf(seq, "]");
1037 }
1038
1039
1040 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
1041 {
1042         char b[BDEVNAME_SIZE];
1043         conf_t *conf = mddev->private;
1044
1045         /*
1046          * If it is not operational, then we have already marked it as dead
1047          * else if it is the last working disks, ignore the error, let the
1048          * next level up know.
1049          * else mark the drive as failed
1050          */
1051         if (test_bit(In_sync, &rdev->flags)
1052             && (conf->raid_disks - mddev->degraded) == 1) {
1053                 /*
1054                  * Don't fail the drive, act as though we were just a
1055                  * normal single drive.
1056                  * However don't try a recovery from this drive as
1057                  * it is very likely to fail.
1058                  */
1059                 conf->recovery_disabled = mddev->recovery_disabled;
1060                 return;
1061         }
1062         if (test_and_clear_bit(In_sync, &rdev->flags)) {
1063                 unsigned long flags;
1064                 spin_lock_irqsave(&conf->device_lock, flags);
1065                 mddev->degraded++;
1066                 set_bit(Faulty, &rdev->flags);
1067                 spin_unlock_irqrestore(&conf->device_lock, flags);
1068                 /*
1069                  * if recovery is running, make sure it aborts.
1070                  */
1071                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1072         } else
1073                 set_bit(Faulty, &rdev->flags);
1074         set_bit(MD_CHANGE_DEVS, &mddev->flags);
1075         printk(KERN_ALERT
1076                "md/raid1:%s: Disk failure on %s, disabling device.\n"
1077                "md/raid1:%s: Operation continuing on %d devices.\n",
1078                mdname(mddev), bdevname(rdev->bdev, b),
1079                mdname(mddev), conf->raid_disks - mddev->degraded);
1080 }
1081
1082 static void print_conf(conf_t *conf)
1083 {
1084         int i;
1085
1086         printk(KERN_DEBUG "RAID1 conf printout:\n");
1087         if (!conf) {
1088                 printk(KERN_DEBUG "(!conf)\n");
1089                 return;
1090         }
1091         printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1092                 conf->raid_disks);
1093
1094         rcu_read_lock();
1095         for (i = 0; i < conf->raid_disks; i++) {
1096                 char b[BDEVNAME_SIZE];
1097                 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1098                 if (rdev)
1099                         printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
1100                                i, !test_bit(In_sync, &rdev->flags),
1101                                !test_bit(Faulty, &rdev->flags),
1102                                bdevname(rdev->bdev,b));
1103         }
1104         rcu_read_unlock();
1105 }
1106
1107 static void close_sync(conf_t *conf)
1108 {
1109         wait_barrier(conf);
1110         allow_barrier(conf);
1111
1112         mempool_destroy(conf->r1buf_pool);
1113         conf->r1buf_pool = NULL;
1114 }
1115
1116 static int raid1_spare_active(mddev_t *mddev)
1117 {
1118         int i;
1119         conf_t *conf = mddev->private;
1120         int count = 0;
1121         unsigned long flags;
1122
1123         /*
1124          * Find all failed disks within the RAID1 configuration
1125          * and mark them readable.
1126          * Called under mddev lock, so rcu protection not needed.
1127          */
1128         for (i = 0; i < conf->raid_disks; i++) {
1129                 mdk_rdev_t *rdev = conf->mirrors[i].rdev;
1130                 if (rdev
1131                     && !test_bit(Faulty, &rdev->flags)
1132                     && !test_and_set_bit(In_sync, &rdev->flags)) {
1133                         count++;
1134                         sysfs_notify_dirent_safe(rdev->sysfs_state);
1135                 }
1136         }
1137         spin_lock_irqsave(&conf->device_lock, flags);
1138         mddev->degraded -= count;
1139         spin_unlock_irqrestore(&conf->device_lock, flags);
1140
1141         print_conf(conf);
1142         return count;
1143 }
1144
1145
1146 static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
1147 {
1148         conf_t *conf = mddev->private;
1149         int err = -EEXIST;
1150         int mirror = 0;
1151         mirror_info_t *p;
1152         int first = 0;
1153         int last = mddev->raid_disks - 1;
1154
1155         if (mddev->recovery_disabled == conf->recovery_disabled)
1156                 return -EBUSY;
1157
1158         if (rdev->badblocks.count)
1159                 return -EINVAL;
1160
1161         if (rdev->raid_disk >= 0)
1162                 first = last = rdev->raid_disk;
1163
1164         for (mirror = first; mirror <= last; mirror++)
1165                 if ( !(p=conf->mirrors+mirror)->rdev) {
1166
1167                         disk_stack_limits(mddev->gendisk, rdev->bdev,
1168                                           rdev->data_offset << 9);
1169                         /* as we don't honour merge_bvec_fn, we must
1170                          * never risk violating it, so limit
1171                          * ->max_segments to one lying with a single
1172                          * page, as a one page request is never in
1173                          * violation.
1174                          */
1175                         if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
1176                                 blk_queue_max_segments(mddev->queue, 1);
1177                                 blk_queue_segment_boundary(mddev->queue,
1178                                                            PAGE_CACHE_SIZE - 1);
1179                         }
1180
1181                         p->head_position = 0;
1182                         rdev->raid_disk = mirror;
1183                         err = 0;
1184                         /* As all devices are equivalent, we don't need a full recovery
1185                          * if this was recently any drive of the array
1186                          */
1187                         if (rdev->saved_raid_disk < 0)
1188                                 conf->fullsync = 1;
1189                         rcu_assign_pointer(p->rdev, rdev);
1190                         break;
1191                 }
1192         md_integrity_add_rdev(rdev, mddev);
1193         print_conf(conf);
1194         return err;
1195 }
1196
1197 static int raid1_remove_disk(mddev_t *mddev, int number)
1198 {
1199         conf_t *conf = mddev->private;
1200         int err = 0;
1201         mdk_rdev_t *rdev;
1202         mirror_info_t *p = conf->mirrors+ number;
1203
1204         print_conf(conf);
1205         rdev = p->rdev;
1206         if (rdev) {
1207                 if (test_bit(In_sync, &rdev->flags) ||
1208                     atomic_read(&rdev->nr_pending)) {
1209                         err = -EBUSY;
1210                         goto abort;
1211                 }
1212                 /* Only remove non-faulty devices if recovery
1213                  * is not possible.
1214                  */
1215                 if (!test_bit(Faulty, &rdev->flags) &&
1216                     mddev->recovery_disabled != conf->recovery_disabled &&
1217                     mddev->degraded < conf->raid_disks) {
1218                         err = -EBUSY;
1219                         goto abort;
1220                 }
1221                 p->rdev = NULL;
1222                 synchronize_rcu();
1223                 if (atomic_read(&rdev->nr_pending)) {
1224                         /* lost the race, try later */
1225                         err = -EBUSY;
1226                         p->rdev = rdev;
1227                         goto abort;
1228                 }
1229                 err = md_integrity_register(mddev);
1230         }
1231 abort:
1232
1233         print_conf(conf);
1234         return err;
1235 }
1236
1237
1238 static void end_sync_read(struct bio *bio, int error)
1239 {
1240         r1bio_t *r1_bio = bio->bi_private;
1241         int i;
1242
1243         for (i=r1_bio->mddev->raid_disks; i--; )
1244                 if (r1_bio->bios[i] == bio)
1245                         break;
1246         BUG_ON(i < 0);
1247         update_head_pos(i, r1_bio);
1248         /*
1249          * we have read a block, now it needs to be re-written,
1250          * or re-read if the read failed.
1251          * We don't do much here, just schedule handling by raid1d
1252          */
1253         if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1254                 set_bit(R1BIO_Uptodate, &r1_bio->state);
1255
1256         if (atomic_dec_and_test(&r1_bio->remaining))
1257                 reschedule_retry(r1_bio);
1258 }
1259
1260 static void end_sync_write(struct bio *bio, int error)
1261 {
1262         int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1263         r1bio_t *r1_bio = bio->bi_private;
1264         mddev_t *mddev = r1_bio->mddev;
1265         conf_t *conf = mddev->private;
1266         int i;
1267         int mirror=0;
1268
1269         for (i = 0; i < conf->raid_disks; i++)
1270                 if (r1_bio->bios[i] == bio) {
1271                         mirror = i;
1272                         break;
1273                 }
1274         if (!uptodate) {
1275                 sector_t sync_blocks = 0;
1276                 sector_t s = r1_bio->sector;
1277                 long sectors_to_go = r1_bio->sectors;
1278                 /* make sure these bits doesn't get cleared. */
1279                 do {
1280                         bitmap_end_sync(mddev->bitmap, s,
1281                                         &sync_blocks, 1);
1282                         s += sync_blocks;
1283                         sectors_to_go -= sync_blocks;
1284                 } while (sectors_to_go > 0);
1285                 md_error(mddev, conf->mirrors[mirror].rdev);
1286         }
1287
1288         update_head_pos(mirror, r1_bio);
1289
1290         if (atomic_dec_and_test(&r1_bio->remaining)) {
1291                 sector_t s = r1_bio->sectors;
1292                 put_buf(r1_bio);
1293                 md_done_sync(mddev, s, uptodate);
1294         }
1295 }
1296
1297 static int fix_sync_read_error(r1bio_t *r1_bio)
1298 {
1299         /* Try some synchronous reads of other devices to get
1300          * good data, much like with normal read errors.  Only
1301          * read into the pages we already have so we don't
1302          * need to re-issue the read request.
1303          * We don't need to freeze the array, because being in an
1304          * active sync request, there is no normal IO, and
1305          * no overlapping syncs.
1306          */
1307         mddev_t *mddev = r1_bio->mddev;
1308         conf_t *conf = mddev->private;
1309         struct bio *bio = r1_bio->bios[r1_bio->read_disk];
1310         sector_t sect = r1_bio->sector;
1311         int sectors = r1_bio->sectors;
1312         int idx = 0;
1313
1314         while(sectors) {
1315                 int s = sectors;
1316                 int d = r1_bio->read_disk;
1317                 int success = 0;
1318                 mdk_rdev_t *rdev;
1319                 int start;
1320
1321                 if (s > (PAGE_SIZE>>9))
1322                         s = PAGE_SIZE >> 9;
1323                 do {
1324                         if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1325                                 /* No rcu protection needed here devices
1326                                  * can only be removed when no resync is
1327                                  * active, and resync is currently active
1328                                  */
1329                                 rdev = conf->mirrors[d].rdev;
1330                                 if (sync_page_io(rdev, sect, s<<9,
1331                                                  bio->bi_io_vec[idx].bv_page,
1332                                                  READ, false)) {
1333                                         success = 1;
1334                                         break;
1335                                 }
1336                         }
1337                         d++;
1338                         if (d == conf->raid_disks)
1339                                 d = 0;
1340                 } while (!success && d != r1_bio->read_disk);
1341
1342                 if (!success) {
1343                         char b[BDEVNAME_SIZE];
1344                         /* Cannot read from anywhere, array is toast */
1345                         md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
1346                         printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O read error"
1347                                " for block %llu\n",
1348                                mdname(mddev),
1349                                bdevname(bio->bi_bdev, b),
1350                                (unsigned long long)r1_bio->sector);
1351                         md_done_sync(mddev, r1_bio->sectors, 0);
1352                         put_buf(r1_bio);
1353                         return 0;
1354                 }
1355
1356                 start = d;
1357                 /* write it back and re-read */
1358                 while (d != r1_bio->read_disk) {
1359                         if (d == 0)
1360                                 d = conf->raid_disks;
1361                         d--;
1362                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1363                                 continue;
1364                         rdev = conf->mirrors[d].rdev;
1365                         if (sync_page_io(rdev, sect, s<<9,
1366                                          bio->bi_io_vec[idx].bv_page,
1367                                          WRITE, false) == 0) {
1368                                 r1_bio->bios[d]->bi_end_io = NULL;
1369                                 rdev_dec_pending(rdev, mddev);
1370                                 md_error(mddev, rdev);
1371                         }
1372                 }
1373                 d = start;
1374                 while (d != r1_bio->read_disk) {
1375                         if (d == 0)
1376                                 d = conf->raid_disks;
1377                         d--;
1378                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1379                                 continue;
1380                         rdev = conf->mirrors[d].rdev;
1381                         if (sync_page_io(rdev, sect, s<<9,
1382                                          bio->bi_io_vec[idx].bv_page,
1383                                          READ, false) == 0)
1384                                 md_error(mddev, rdev);
1385                         else
1386                                 atomic_add(s, &rdev->corrected_errors);
1387                 }
1388                 sectors -= s;
1389                 sect += s;
1390                 idx ++;
1391         }
1392         set_bit(R1BIO_Uptodate, &r1_bio->state);
1393         set_bit(BIO_UPTODATE, &bio->bi_flags);
1394         return 1;
1395 }
1396
1397 static int process_checks(r1bio_t *r1_bio)
1398 {
1399         /* We have read all readable devices.  If we haven't
1400          * got the block, then there is no hope left.
1401          * If we have, then we want to do a comparison
1402          * and skip the write if everything is the same.
1403          * If any blocks failed to read, then we need to
1404          * attempt an over-write
1405          */
1406         mddev_t *mddev = r1_bio->mddev;
1407         conf_t *conf = mddev->private;
1408         int primary;
1409         int i;
1410
1411         for (primary = 0; primary < conf->raid_disks; primary++)
1412                 if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1413                     test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
1414                         r1_bio->bios[primary]->bi_end_io = NULL;
1415                         rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1416                         break;
1417                 }
1418         r1_bio->read_disk = primary;
1419         for (i = 0; i < conf->raid_disks; i++) {
1420                 int j;
1421                 int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
1422                 struct bio *pbio = r1_bio->bios[primary];
1423                 struct bio *sbio = r1_bio->bios[i];
1424                 int size;
1425
1426                 if (r1_bio->bios[i]->bi_end_io != end_sync_read)
1427                         continue;
1428
1429                 if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
1430                         for (j = vcnt; j-- ; ) {
1431                                 struct page *p, *s;
1432                                 p = pbio->bi_io_vec[j].bv_page;
1433                                 s = sbio->bi_io_vec[j].bv_page;
1434                                 if (memcmp(page_address(p),
1435                                            page_address(s),
1436                                            PAGE_SIZE))
1437                                         break;
1438                         }
1439                 } else
1440                         j = 0;
1441                 if (j >= 0)
1442                         mddev->resync_mismatches += r1_bio->sectors;
1443                 if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
1444                               && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
1445                         /* No need to write to this device. */
1446                         sbio->bi_end_io = NULL;
1447                         rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1448                         continue;
1449                 }
1450                 /* fixup the bio for reuse */
1451                 sbio->bi_vcnt = vcnt;
1452                 sbio->bi_size = r1_bio->sectors << 9;
1453                 sbio->bi_idx = 0;
1454                 sbio->bi_phys_segments = 0;
1455                 sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1456                 sbio->bi_flags |= 1 << BIO_UPTODATE;
1457                 sbio->bi_next = NULL;
1458                 sbio->bi_sector = r1_bio->sector +
1459                         conf->mirrors[i].rdev->data_offset;
1460                 sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1461                 size = sbio->bi_size;
1462                 for (j = 0; j < vcnt ; j++) {
1463                         struct bio_vec *bi;
1464                         bi = &sbio->bi_io_vec[j];
1465                         bi->bv_offset = 0;
1466                         if (size > PAGE_SIZE)
1467                                 bi->bv_len = PAGE_SIZE;
1468                         else
1469                                 bi->bv_len = size;
1470                         size -= PAGE_SIZE;
1471                         memcpy(page_address(bi->bv_page),
1472                                page_address(pbio->bi_io_vec[j].bv_page),
1473                                PAGE_SIZE);
1474                 }
1475         }
1476         return 0;
1477 }
1478
1479 static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
1480 {
1481         conf_t *conf = mddev->private;
1482         int i;
1483         int disks = conf->raid_disks;
1484         struct bio *bio, *wbio;
1485
1486         bio = r1_bio->bios[r1_bio->read_disk];
1487
1488         if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
1489                 /* ouch - failed to read all of that. */
1490                 if (!fix_sync_read_error(r1_bio))
1491                         return;
1492
1493         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1494                 if (process_checks(r1_bio) < 0)
1495                         return;
1496         /*
1497          * schedule writes
1498          */
1499         atomic_set(&r1_bio->remaining, 1);
1500         for (i = 0; i < disks ; i++) {
1501                 wbio = r1_bio->bios[i];
1502                 if (wbio->bi_end_io == NULL ||
1503                     (wbio->bi_end_io == end_sync_read &&
1504                      (i == r1_bio->read_disk ||
1505                       !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
1506                         continue;
1507
1508                 wbio->bi_rw = WRITE;
1509                 wbio->bi_end_io = end_sync_write;
1510                 atomic_inc(&r1_bio->remaining);
1511                 md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1512
1513                 generic_make_request(wbio);
1514         }
1515
1516         if (atomic_dec_and_test(&r1_bio->remaining)) {
1517                 /* if we're here, all write(s) have completed, so clean up */
1518                 md_done_sync(mddev, r1_bio->sectors, 1);
1519                 put_buf(r1_bio);
1520         }
1521 }
1522
1523 /*
1524  * This is a kernel thread which:
1525  *
1526  *      1.      Retries failed read operations on working mirrors.
1527  *      2.      Updates the raid superblock when problems encounter.
1528  *      3.      Performs writes following reads for array synchronising.
1529  */
1530
1531 static void fix_read_error(conf_t *conf, int read_disk,
1532                            sector_t sect, int sectors)
1533 {
1534         mddev_t *mddev = conf->mddev;
1535         while(sectors) {
1536                 int s = sectors;
1537                 int d = read_disk;
1538                 int success = 0;
1539                 int start;
1540                 mdk_rdev_t *rdev;
1541
1542                 if (s > (PAGE_SIZE>>9))
1543                         s = PAGE_SIZE >> 9;
1544
1545                 do {
1546                         /* Note: no rcu protection needed here
1547                          * as this is synchronous in the raid1d thread
1548                          * which is the thread that might remove
1549                          * a device.  If raid1d ever becomes multi-threaded....
1550                          */
1551                         sector_t first_bad;
1552                         int bad_sectors;
1553
1554                         rdev = conf->mirrors[d].rdev;
1555                         if (rdev &&
1556                             test_bit(In_sync, &rdev->flags) &&
1557                             is_badblock(rdev, sect, s,
1558                                         &first_bad, &bad_sectors) == 0 &&
1559                             sync_page_io(rdev, sect, s<<9,
1560                                          conf->tmppage, READ, false))
1561                                 success = 1;
1562                         else {
1563                                 d++;
1564                                 if (d == conf->raid_disks)
1565                                         d = 0;
1566                         }
1567                 } while (!success && d != read_disk);
1568
1569                 if (!success) {
1570                         /* Cannot read from anywhere -- bye bye array */
1571                         md_error(mddev, conf->mirrors[read_disk].rdev);
1572                         break;
1573                 }
1574                 /* write it back and re-read */
1575                 start = d;
1576                 while (d != read_disk) {
1577                         if (d==0)
1578                                 d = conf->raid_disks;
1579                         d--;
1580                         rdev = conf->mirrors[d].rdev;
1581                         if (rdev &&
1582                             test_bit(In_sync, &rdev->flags)) {
1583                                 if (sync_page_io(rdev, sect, s<<9,
1584                                                  conf->tmppage, WRITE, false)
1585                                     == 0)
1586                                         /* Well, this device is dead */
1587                                         md_error(mddev, rdev);
1588                         }
1589                 }
1590                 d = start;
1591                 while (d != read_disk) {
1592                         char b[BDEVNAME_SIZE];
1593                         if (d==0)
1594                                 d = conf->raid_disks;
1595                         d--;
1596                         rdev = conf->mirrors[d].rdev;
1597                         if (rdev &&
1598                             test_bit(In_sync, &rdev->flags)) {
1599                                 if (sync_page_io(rdev, sect, s<<9,
1600                                                  conf->tmppage, READ, false)
1601                                     == 0)
1602                                         /* Well, this device is dead */
1603                                         md_error(mddev, rdev);
1604                                 else {
1605                                         atomic_add(s, &rdev->corrected_errors);
1606                                         printk(KERN_INFO
1607                                                "md/raid1:%s: read error corrected "
1608                                                "(%d sectors at %llu on %s)\n",
1609                                                mdname(mddev), s,
1610                                                (unsigned long long)(sect +
1611                                                    rdev->data_offset),
1612                                                bdevname(rdev->bdev, b));
1613                                 }
1614                         }
1615                 }
1616                 sectors -= s;
1617                 sect += s;
1618         }
1619 }
1620
1621 static void raid1d(mddev_t *mddev)
1622 {
1623         r1bio_t *r1_bio;
1624         struct bio *bio;
1625         unsigned long flags;
1626         conf_t *conf = mddev->private;
1627         struct list_head *head = &conf->retry_list;
1628         mdk_rdev_t *rdev;
1629         struct blk_plug plug;
1630
1631         md_check_recovery(mddev);
1632
1633         blk_start_plug(&plug);
1634         for (;;) {
1635                 char b[BDEVNAME_SIZE];
1636
1637                 if (atomic_read(&mddev->plug_cnt) == 0)
1638                         flush_pending_writes(conf);
1639
1640                 spin_lock_irqsave(&conf->device_lock, flags);
1641                 if (list_empty(head)) {
1642                         spin_unlock_irqrestore(&conf->device_lock, flags);
1643                         break;
1644                 }
1645                 r1_bio = list_entry(head->prev, r1bio_t, retry_list);
1646                 list_del(head->prev);
1647                 conf->nr_queued--;
1648                 spin_unlock_irqrestore(&conf->device_lock, flags);
1649
1650                 mddev = r1_bio->mddev;
1651                 conf = mddev->private;
1652                 if (test_bit(R1BIO_IsSync, &r1_bio->state))
1653                         sync_request_write(mddev, r1_bio);
1654                 else if (test_bit(R1BIO_ReadError, &r1_bio->state)) {
1655                         int disk;
1656                         int max_sectors;
1657
1658                         clear_bit(R1BIO_ReadError, &r1_bio->state);
1659                         /* we got a read error. Maybe the drive is bad.  Maybe just
1660                          * the block and we can fix it.
1661                          * We freeze all other IO, and try reading the block from
1662                          * other devices.  When we find one, we re-write
1663                          * and check it that fixes the read error.
1664                          * This is all done synchronously while the array is
1665                          * frozen
1666                          */
1667                         if (mddev->ro == 0) {
1668                                 freeze_array(conf);
1669                                 fix_read_error(conf, r1_bio->read_disk,
1670                                                r1_bio->sector,
1671                                                r1_bio->sectors);
1672                                 unfreeze_array(conf);
1673                         } else
1674                                 md_error(mddev,
1675                                          conf->mirrors[r1_bio->read_disk].rdev);
1676
1677                         bio = r1_bio->bios[r1_bio->read_disk];
1678                         bdevname(bio->bi_bdev, b);
1679 read_more:
1680                         disk = read_balance(conf, r1_bio, &max_sectors);
1681                         if (disk == -1) {
1682                                 printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O"
1683                                        " read error for block %llu\n",
1684                                        mdname(mddev), b,
1685                                        (unsigned long long)r1_bio->sector);
1686                                 raid_end_bio_io(r1_bio);
1687                         } else {
1688                                 const unsigned long do_sync = r1_bio->master_bio->bi_rw & REQ_SYNC;
1689                                 if (bio) {
1690                                         r1_bio->bios[r1_bio->read_disk] =
1691                                                 mddev->ro ? IO_BLOCKED : NULL;
1692                                         bio_put(bio);
1693                                 }
1694                                 r1_bio->read_disk = disk;
1695                                 bio = bio_clone_mddev(r1_bio->master_bio,
1696                                                       GFP_NOIO, mddev);
1697                                 md_trim_bio(bio,
1698                                             r1_bio->sector - bio->bi_sector,
1699                                             max_sectors);
1700                                 r1_bio->bios[r1_bio->read_disk] = bio;
1701                                 rdev = conf->mirrors[disk].rdev;
1702                                 printk_ratelimited(
1703                                         KERN_ERR
1704                                         "md/raid1:%s: redirecting sector %llu"
1705                                         " to other mirror: %s\n",
1706                                         mdname(mddev),
1707                                         (unsigned long long)r1_bio->sector,
1708                                         bdevname(rdev->bdev, b));
1709                                 bio->bi_sector = r1_bio->sector + rdev->data_offset;
1710                                 bio->bi_bdev = rdev->bdev;
1711                                 bio->bi_end_io = raid1_end_read_request;
1712                                 bio->bi_rw = READ | do_sync;
1713                                 bio->bi_private = r1_bio;
1714                                 if (max_sectors < r1_bio->sectors) {
1715                                         /* Drat - have to split this up more */
1716                                         struct bio *mbio = r1_bio->master_bio;
1717                                         int sectors_handled =
1718                                                 r1_bio->sector + max_sectors
1719                                                 - mbio->bi_sector;
1720                                         r1_bio->sectors = max_sectors;
1721                                         spin_lock_irq(&conf->device_lock);
1722                                         if (mbio->bi_phys_segments == 0)
1723                                                 mbio->bi_phys_segments = 2;
1724                                         else
1725                                                 mbio->bi_phys_segments++;
1726                                         spin_unlock_irq(&conf->device_lock);
1727                                         generic_make_request(bio);
1728                                         bio = NULL;
1729
1730                                         r1_bio = mempool_alloc(conf->r1bio_pool,
1731                                                                GFP_NOIO);
1732
1733                                         r1_bio->master_bio = mbio;
1734                                         r1_bio->sectors = (mbio->bi_size >> 9)
1735                                                 - sectors_handled;
1736                                         r1_bio->state = 0;
1737                                         set_bit(R1BIO_ReadError,
1738                                                 &r1_bio->state);
1739                                         r1_bio->mddev = mddev;
1740                                         r1_bio->sector = mbio->bi_sector
1741                                                 + sectors_handled;
1742
1743                                         goto read_more;
1744                                 } else
1745                                         generic_make_request(bio);
1746                         }
1747                 } else {
1748                         /* just a partial read to be scheduled from separate
1749                          * context
1750                          */
1751                         generic_make_request(r1_bio->bios[r1_bio->read_disk]);
1752                 }
1753                 cond_resched();
1754         }
1755         blk_finish_plug(&plug);
1756 }
1757
1758
1759 static int init_resync(conf_t *conf)
1760 {
1761         int buffs;
1762
1763         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1764         BUG_ON(conf->r1buf_pool);
1765         conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
1766                                           conf->poolinfo);
1767         if (!conf->r1buf_pool)
1768                 return -ENOMEM;
1769         conf->next_resync = 0;
1770         return 0;
1771 }
1772
1773 /*
1774  * perform a "sync" on one "block"
1775  *
1776  * We need to make sure that no normal I/O request - particularly write
1777  * requests - conflict with active sync requests.
1778  *
1779  * This is achieved by tracking pending requests and a 'barrier' concept
1780  * that can be installed to exclude normal IO requests.
1781  */
1782
1783 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
1784 {
1785         conf_t *conf = mddev->private;
1786         r1bio_t *r1_bio;
1787         struct bio *bio;
1788         sector_t max_sector, nr_sectors;
1789         int disk = -1;
1790         int i;
1791         int wonly = -1;
1792         int write_targets = 0, read_targets = 0;
1793         sector_t sync_blocks;
1794         int still_degraded = 0;
1795
1796         if (!conf->r1buf_pool)
1797                 if (init_resync(conf))
1798                         return 0;
1799
1800         max_sector = mddev->dev_sectors;
1801         if (sector_nr >= max_sector) {
1802                 /* If we aborted, we need to abort the
1803                  * sync on the 'current' bitmap chunk (there will
1804                  * only be one in raid1 resync.
1805                  * We can find the current addess in mddev->curr_resync
1806                  */
1807                 if (mddev->curr_resync < max_sector) /* aborted */
1808                         bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1809                                                 &sync_blocks, 1);
1810                 else /* completed sync */
1811                         conf->fullsync = 0;
1812
1813                 bitmap_close_sync(mddev->bitmap);
1814                 close_sync(conf);
1815                 return 0;
1816         }
1817
1818         if (mddev->bitmap == NULL &&
1819             mddev->recovery_cp == MaxSector &&
1820             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
1821             conf->fullsync == 0) {
1822                 *skipped = 1;
1823                 return max_sector - sector_nr;
1824         }
1825         /* before building a request, check if we can skip these blocks..
1826          * This call the bitmap_start_sync doesn't actually record anything
1827          */
1828         if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
1829             !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1830                 /* We can skip this block, and probably several more */
1831                 *skipped = 1;
1832                 return sync_blocks;
1833         }
1834         /*
1835          * If there is non-resync activity waiting for a turn,
1836          * and resync is going fast enough,
1837          * then let it though before starting on this new sync request.
1838          */
1839         if (!go_faster && conf->nr_waiting)
1840                 msleep_interruptible(1000);
1841
1842         bitmap_cond_end_sync(mddev->bitmap, sector_nr);
1843         r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
1844         raise_barrier(conf);
1845
1846         conf->next_resync = sector_nr;
1847
1848         rcu_read_lock();
1849         /*
1850          * If we get a correctably read error during resync or recovery,
1851          * we might want to read from a different device.  So we
1852          * flag all drives that could conceivably be read from for READ,
1853          * and any others (which will be non-In_sync devices) for WRITE.
1854          * If a read fails, we try reading from something else for which READ
1855          * is OK.
1856          */
1857
1858         r1_bio->mddev = mddev;
1859         r1_bio->sector = sector_nr;
1860         r1_bio->state = 0;
1861         set_bit(R1BIO_IsSync, &r1_bio->state);
1862
1863         for (i=0; i < conf->raid_disks; i++) {
1864                 mdk_rdev_t *rdev;
1865                 bio = r1_bio->bios[i];
1866
1867                 /* take from bio_init */
1868                 bio->bi_next = NULL;
1869                 bio->bi_flags &= ~(BIO_POOL_MASK-1);
1870                 bio->bi_flags |= 1 << BIO_UPTODATE;
1871                 bio->bi_comp_cpu = -1;
1872                 bio->bi_rw = READ;
1873                 bio->bi_vcnt = 0;
1874                 bio->bi_idx = 0;
1875                 bio->bi_phys_segments = 0;
1876                 bio->bi_size = 0;
1877                 bio->bi_end_io = NULL;
1878                 bio->bi_private = NULL;
1879
1880                 rdev = rcu_dereference(conf->mirrors[i].rdev);
1881                 if (rdev == NULL ||
1882                            test_bit(Faulty, &rdev->flags)) {
1883                         still_degraded = 1;
1884                         continue;
1885                 } else if (!test_bit(In_sync, &rdev->flags)) {
1886                         bio->bi_rw = WRITE;
1887                         bio->bi_end_io = end_sync_write;
1888                         write_targets ++;
1889                 } else {
1890                         /* may need to read from here */
1891                         bio->bi_rw = READ;
1892                         bio->bi_end_io = end_sync_read;
1893                         if (test_bit(WriteMostly, &rdev->flags)) {
1894                                 if (wonly < 0)
1895                                         wonly = i;
1896                         } else {
1897                                 if (disk < 0)
1898                                         disk = i;
1899                         }
1900                         read_targets++;
1901                 }
1902                 atomic_inc(&rdev->nr_pending);
1903                 bio->bi_sector = sector_nr + rdev->data_offset;
1904                 bio->bi_bdev = rdev->bdev;
1905                 bio->bi_private = r1_bio;
1906         }
1907         rcu_read_unlock();
1908         if (disk < 0)
1909                 disk = wonly;
1910         r1_bio->read_disk = disk;
1911
1912         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
1913                 /* extra read targets are also write targets */
1914                 write_targets += read_targets-1;
1915
1916         if (write_targets == 0 || read_targets == 0) {
1917                 /* There is nowhere to write, so all non-sync
1918                  * drives must be failed - so we are finished
1919                  */
1920                 sector_t rv = max_sector - sector_nr;
1921                 *skipped = 1;
1922                 put_buf(r1_bio);
1923                 return rv;
1924         }
1925
1926         if (max_sector > mddev->resync_max)
1927                 max_sector = mddev->resync_max; /* Don't do IO beyond here */
1928         nr_sectors = 0;
1929         sync_blocks = 0;
1930         do {
1931                 struct page *page;
1932                 int len = PAGE_SIZE;
1933                 if (sector_nr + (len>>9) > max_sector)
1934                         len = (max_sector - sector_nr) << 9;
1935                 if (len == 0)
1936                         break;
1937                 if (sync_blocks == 0) {
1938                         if (!bitmap_start_sync(mddev->bitmap, sector_nr,
1939                                                &sync_blocks, still_degraded) &&
1940                             !conf->fullsync &&
1941                             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1942                                 break;
1943                         BUG_ON(sync_blocks < (PAGE_SIZE>>9));
1944                         if ((len >> 9) > sync_blocks)
1945                                 len = sync_blocks<<9;
1946                 }
1947
1948                 for (i=0 ; i < conf->raid_disks; i++) {
1949                         bio = r1_bio->bios[i];
1950                         if (bio->bi_end_io) {
1951                                 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
1952                                 if (bio_add_page(bio, page, len, 0) == 0) {
1953                                         /* stop here */
1954                                         bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
1955                                         while (i > 0) {
1956                                                 i--;
1957                                                 bio = r1_bio->bios[i];
1958                                                 if (bio->bi_end_io==NULL)
1959                                                         continue;
1960                                                 /* remove last page from this bio */
1961                                                 bio->bi_vcnt--;
1962                                                 bio->bi_size -= len;
1963                                                 bio->bi_flags &= ~(1<< BIO_SEG_VALID);
1964                                         }
1965                                         goto bio_full;
1966                                 }
1967                         }
1968                 }
1969                 nr_sectors += len>>9;
1970                 sector_nr += len>>9;
1971                 sync_blocks -= (len>>9);
1972         } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
1973  bio_full:
1974         r1_bio->sectors = nr_sectors;
1975
1976         /* For a user-requested sync, we read all readable devices and do a
1977          * compare
1978          */
1979         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1980                 atomic_set(&r1_bio->remaining, read_targets);
1981                 for (i=0; i<conf->raid_disks; i++) {
1982                         bio = r1_bio->bios[i];
1983                         if (bio->bi_end_io == end_sync_read) {
1984                                 md_sync_acct(bio->bi_bdev, nr_sectors);
1985                                 generic_make_request(bio);
1986                         }
1987                 }
1988         } else {
1989                 atomic_set(&r1_bio->remaining, 1);
1990                 bio = r1_bio->bios[r1_bio->read_disk];
1991                 md_sync_acct(bio->bi_bdev, nr_sectors);
1992                 generic_make_request(bio);
1993
1994         }
1995         return nr_sectors;
1996 }
1997
1998 static sector_t raid1_size(mddev_t *mddev, sector_t sectors, int raid_disks)
1999 {
2000         if (sectors)
2001                 return sectors;
2002
2003         return mddev->dev_sectors;
2004 }
2005
2006 static conf_t *setup_conf(mddev_t *mddev)
2007 {
2008         conf_t *conf;
2009         int i;
2010         mirror_info_t *disk;
2011         mdk_rdev_t *rdev;
2012         int err = -ENOMEM;
2013
2014         conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
2015         if (!conf)
2016                 goto abort;
2017
2018         conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
2019                                  GFP_KERNEL);
2020         if (!conf->mirrors)
2021                 goto abort;
2022
2023         conf->tmppage = alloc_page(GFP_KERNEL);
2024         if (!conf->tmppage)
2025                 goto abort;
2026
2027         conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
2028         if (!conf->poolinfo)
2029                 goto abort;
2030         conf->poolinfo->raid_disks = mddev->raid_disks;
2031         conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2032                                           r1bio_pool_free,
2033                                           conf->poolinfo);
2034         if (!conf->r1bio_pool)
2035                 goto abort;
2036
2037         conf->poolinfo->mddev = mddev;
2038
2039         spin_lock_init(&conf->device_lock);
2040         list_for_each_entry(rdev, &mddev->disks, same_set) {
2041                 int disk_idx = rdev->raid_disk;
2042                 if (disk_idx >= mddev->raid_disks
2043                     || disk_idx < 0)
2044                         continue;
2045                 disk = conf->mirrors + disk_idx;
2046
2047                 disk->rdev = rdev;
2048
2049                 disk->head_position = 0;
2050         }
2051         conf->raid_disks = mddev->raid_disks;
2052         conf->mddev = mddev;
2053         INIT_LIST_HEAD(&conf->retry_list);
2054
2055         spin_lock_init(&conf->resync_lock);
2056         init_waitqueue_head(&conf->wait_barrier);
2057
2058         bio_list_init(&conf->pending_bio_list);
2059
2060         conf->last_used = -1;
2061         for (i = 0; i < conf->raid_disks; i++) {
2062
2063                 disk = conf->mirrors + i;
2064
2065                 if (!disk->rdev ||
2066                     !test_bit(In_sync, &disk->rdev->flags)) {
2067                         disk->head_position = 0;
2068                         if (disk->rdev)
2069                                 conf->fullsync = 1;
2070                 } else if (conf->last_used < 0)
2071                         /*
2072                          * The first working device is used as a
2073                          * starting point to read balancing.
2074                          */
2075                         conf->last_used = i;
2076         }
2077
2078         err = -EIO;
2079         if (conf->last_used < 0) {
2080                 printk(KERN_ERR "md/raid1:%s: no operational mirrors\n",
2081                        mdname(mddev));
2082                 goto abort;
2083         }
2084         err = -ENOMEM;
2085         conf->thread = md_register_thread(raid1d, mddev, NULL);
2086         if (!conf->thread) {
2087                 printk(KERN_ERR
2088                        "md/raid1:%s: couldn't allocate thread\n",
2089                        mdname(mddev));
2090                 goto abort;
2091         }
2092
2093         return conf;
2094
2095  abort:
2096         if (conf) {
2097                 if (conf->r1bio_pool)
2098                         mempool_destroy(conf->r1bio_pool);
2099                 kfree(conf->mirrors);
2100                 safe_put_page(conf->tmppage);
2101                 kfree(conf->poolinfo);
2102                 kfree(conf);
2103         }
2104         return ERR_PTR(err);
2105 }
2106
2107 static int run(mddev_t *mddev)
2108 {
2109         conf_t *conf;
2110         int i;
2111         mdk_rdev_t *rdev;
2112
2113         if (mddev->level != 1) {
2114                 printk(KERN_ERR "md/raid1:%s: raid level not set to mirroring (%d)\n",
2115                        mdname(mddev), mddev->level);
2116                 return -EIO;
2117         }
2118         if (mddev->reshape_position != MaxSector) {
2119                 printk(KERN_ERR "md/raid1:%s: reshape_position set but not supported\n",
2120                        mdname(mddev));
2121                 return -EIO;
2122         }
2123         /*
2124          * copy the already verified devices into our private RAID1
2125          * bookkeeping area. [whatever we allocate in run(),
2126          * should be freed in stop()]
2127          */
2128         if (mddev->private == NULL)
2129                 conf = setup_conf(mddev);
2130         else
2131                 conf = mddev->private;
2132
2133         if (IS_ERR(conf))
2134                 return PTR_ERR(conf);
2135
2136         list_for_each_entry(rdev, &mddev->disks, same_set) {
2137                 if (!mddev->gendisk)
2138                         continue;
2139                 disk_stack_limits(mddev->gendisk, rdev->bdev,
2140                                   rdev->data_offset << 9);
2141                 /* as we don't honour merge_bvec_fn, we must never risk
2142                  * violating it, so limit ->max_segments to 1 lying within
2143                  * a single page, as a one page request is never in violation.
2144                  */
2145                 if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
2146                         blk_queue_max_segments(mddev->queue, 1);
2147                         blk_queue_segment_boundary(mddev->queue,
2148                                                    PAGE_CACHE_SIZE - 1);
2149                 }
2150                 if (rdev->badblocks.count) {
2151                         printk(KERN_ERR "md/raid1: Cannot handle bad blocks yet\n");
2152                         return -EINVAL;
2153                 }
2154         }
2155
2156         mddev->degraded = 0;
2157         for (i=0; i < conf->raid_disks; i++)
2158                 if (conf->mirrors[i].rdev == NULL ||
2159                     !test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
2160                     test_bit(Faulty, &conf->mirrors[i].rdev->flags))
2161                         mddev->degraded++;
2162
2163         if (conf->raid_disks - mddev->degraded == 1)
2164                 mddev->recovery_cp = MaxSector;
2165
2166         if (mddev->recovery_cp != MaxSector)
2167                 printk(KERN_NOTICE "md/raid1:%s: not clean"
2168                        " -- starting background reconstruction\n",
2169                        mdname(mddev));
2170         printk(KERN_INFO
2171                 "md/raid1:%s: active with %d out of %d mirrors\n",
2172                 mdname(mddev), mddev->raid_disks - mddev->degraded,
2173                 mddev->raid_disks);
2174
2175         /*
2176          * Ok, everything is just fine now
2177          */
2178         mddev->thread = conf->thread;
2179         conf->thread = NULL;
2180         mddev->private = conf;
2181
2182         md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
2183
2184         if (mddev->queue) {
2185                 mddev->queue->backing_dev_info.congested_fn = raid1_congested;
2186                 mddev->queue->backing_dev_info.congested_data = mddev;
2187         }
2188         return md_integrity_register(mddev);
2189 }
2190
2191 static int stop(mddev_t *mddev)
2192 {
2193         conf_t *conf = mddev->private;
2194         struct bitmap *bitmap = mddev->bitmap;
2195
2196         /* wait for behind writes to complete */
2197         if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
2198                 printk(KERN_INFO "md/raid1:%s: behind writes in progress - waiting to stop.\n",
2199                        mdname(mddev));
2200                 /* need to kick something here to make sure I/O goes? */
2201                 wait_event(bitmap->behind_wait,
2202                            atomic_read(&bitmap->behind_writes) == 0);
2203         }
2204
2205         raise_barrier(conf);
2206         lower_barrier(conf);
2207
2208         md_unregister_thread(mddev->thread);
2209         mddev->thread = NULL;
2210         if (conf->r1bio_pool)
2211                 mempool_destroy(conf->r1bio_pool);
2212         kfree(conf->mirrors);
2213         kfree(conf->poolinfo);
2214         kfree(conf);
2215         mddev->private = NULL;
2216         return 0;
2217 }
2218
2219 static int raid1_resize(mddev_t *mddev, sector_t sectors)
2220 {
2221         /* no resync is happening, and there is enough space
2222          * on all devices, so we can resize.
2223          * We need to make sure resync covers any new space.
2224          * If the array is shrinking we should possibly wait until
2225          * any io in the removed space completes, but it hardly seems
2226          * worth it.
2227          */
2228         md_set_array_sectors(mddev, raid1_size(mddev, sectors, 0));
2229         if (mddev->array_sectors > raid1_size(mddev, sectors, 0))
2230                 return -EINVAL;
2231         set_capacity(mddev->gendisk, mddev->array_sectors);
2232         revalidate_disk(mddev->gendisk);
2233         if (sectors > mddev->dev_sectors &&
2234             mddev->recovery_cp > mddev->dev_sectors) {
2235                 mddev->recovery_cp = mddev->dev_sectors;
2236                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2237         }
2238         mddev->dev_sectors = sectors;
2239         mddev->resync_max_sectors = sectors;
2240         return 0;
2241 }
2242
2243 static int raid1_reshape(mddev_t *mddev)
2244 {
2245         /* We need to:
2246          * 1/ resize the r1bio_pool
2247          * 2/ resize conf->mirrors
2248          *
2249          * We allocate a new r1bio_pool if we can.
2250          * Then raise a device barrier and wait until all IO stops.
2251          * Then resize conf->mirrors and swap in the new r1bio pool.
2252          *
2253          * At the same time, we "pack" the devices so that all the missing
2254          * devices have the higher raid_disk numbers.
2255          */
2256         mempool_t *newpool, *oldpool;
2257         struct pool_info *newpoolinfo;
2258         mirror_info_t *newmirrors;
2259         conf_t *conf = mddev->private;
2260         int cnt, raid_disks;
2261         unsigned long flags;
2262         int d, d2, err;
2263
2264         /* Cannot change chunk_size, layout, or level */
2265         if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
2266             mddev->layout != mddev->new_layout ||
2267             mddev->level != mddev->new_level) {
2268                 mddev->new_chunk_sectors = mddev->chunk_sectors;
2269                 mddev->new_layout = mddev->layout;
2270                 mddev->new_level = mddev->level;
2271                 return -EINVAL;
2272         }
2273
2274         err = md_allow_write(mddev);
2275         if (err)
2276                 return err;
2277
2278         raid_disks = mddev->raid_disks + mddev->delta_disks;
2279
2280         if (raid_disks < conf->raid_disks) {
2281                 cnt=0;
2282                 for (d= 0; d < conf->raid_disks; d++)
2283                         if (conf->mirrors[d].rdev)
2284                                 cnt++;
2285                 if (cnt > raid_disks)
2286                         return -EBUSY;
2287         }
2288
2289         newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
2290         if (!newpoolinfo)
2291                 return -ENOMEM;
2292         newpoolinfo->mddev = mddev;
2293         newpoolinfo->raid_disks = raid_disks;
2294
2295         newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2296                                  r1bio_pool_free, newpoolinfo);
2297         if (!newpool) {
2298                 kfree(newpoolinfo);
2299                 return -ENOMEM;
2300         }
2301         newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
2302         if (!newmirrors) {
2303                 kfree(newpoolinfo);
2304                 mempool_destroy(newpool);
2305                 return -ENOMEM;
2306         }
2307
2308         raise_barrier(conf);
2309
2310         /* ok, everything is stopped */
2311         oldpool = conf->r1bio_pool;
2312         conf->r1bio_pool = newpool;
2313
2314         for (d = d2 = 0; d < conf->raid_disks; d++) {
2315                 mdk_rdev_t *rdev = conf->mirrors[d].rdev;
2316                 if (rdev && rdev->raid_disk != d2) {
2317                         sysfs_unlink_rdev(mddev, rdev);
2318                         rdev->raid_disk = d2;
2319                         sysfs_unlink_rdev(mddev, rdev);
2320                         if (sysfs_link_rdev(mddev, rdev))
2321                                 printk(KERN_WARNING
2322                                        "md/raid1:%s: cannot register rd%d\n",
2323                                        mdname(mddev), rdev->raid_disk);
2324                 }
2325                 if (rdev)
2326                         newmirrors[d2++].rdev = rdev;
2327         }
2328         kfree(conf->mirrors);
2329         conf->mirrors = newmirrors;
2330         kfree(conf->poolinfo);
2331         conf->poolinfo = newpoolinfo;
2332
2333         spin_lock_irqsave(&conf->device_lock, flags);
2334         mddev->degraded += (raid_disks - conf->raid_disks);
2335         spin_unlock_irqrestore(&conf->device_lock, flags);
2336         conf->raid_disks = mddev->raid_disks = raid_disks;
2337         mddev->delta_disks = 0;
2338
2339         conf->last_used = 0; /* just make sure it is in-range */
2340         lower_barrier(conf);
2341
2342         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2343         md_wakeup_thread(mddev->thread);
2344
2345         mempool_destroy(oldpool);
2346         return 0;
2347 }
2348
2349 static void raid1_quiesce(mddev_t *mddev, int state)
2350 {
2351         conf_t *conf = mddev->private;
2352
2353         switch(state) {
2354         case 2: /* wake for suspend */
2355                 wake_up(&conf->wait_barrier);
2356                 break;
2357         case 1:
2358                 raise_barrier(conf);
2359                 break;
2360         case 0:
2361                 lower_barrier(conf);
2362                 break;
2363         }
2364 }
2365
2366 static void *raid1_takeover(mddev_t *mddev)
2367 {
2368         /* raid1 can take over:
2369          *  raid5 with 2 devices, any layout or chunk size
2370          */
2371         if (mddev->level == 5 && mddev->raid_disks == 2) {
2372                 conf_t *conf;
2373                 mddev->new_level = 1;
2374                 mddev->new_layout = 0;
2375                 mddev->new_chunk_sectors = 0;
2376                 conf = setup_conf(mddev);
2377                 if (!IS_ERR(conf))
2378                         conf->barrier = 1;
2379                 return conf;
2380         }
2381         return ERR_PTR(-EINVAL);
2382 }
2383
2384 static struct mdk_personality raid1_personality =
2385 {
2386         .name           = "raid1",
2387         .level          = 1,
2388         .owner          = THIS_MODULE,
2389         .make_request   = make_request,
2390         .run            = run,
2391         .stop           = stop,
2392         .status         = status,
2393         .error_handler  = error,
2394         .hot_add_disk   = raid1_add_disk,
2395         .hot_remove_disk= raid1_remove_disk,
2396         .spare_active   = raid1_spare_active,
2397         .sync_request   = sync_request,
2398         .resize         = raid1_resize,
2399         .size           = raid1_size,
2400         .check_reshape  = raid1_reshape,
2401         .quiesce        = raid1_quiesce,
2402         .takeover       = raid1_takeover,
2403 };
2404
2405 static int __init raid_init(void)
2406 {
2407         return register_md_personality(&raid1_personality);
2408 }
2409
2410 static void raid_exit(void)
2411 {
2412         unregister_md_personality(&raid1_personality);
2413 }
2414
2415 module_init(raid_init);
2416 module_exit(raid_exit);
2417 MODULE_LICENSE("GPL");
2418 MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
2419 MODULE_ALIAS("md-personality-3"); /* RAID1 */
2420 MODULE_ALIAS("md-raid1");
2421 MODULE_ALIAS("md-level-1");