drivers/md/raid10.c

   1 /*
   2  * raid10.c : Multiple Devices driver for Linux
   3  *
   4  * Copyright (C) 2000-2004 Neil Brown
   5  *
   6  * RAID-10 support for md.
   7  *
   8  * Base on code in raid1.c.  See raid1.c for further copyright information.
   9  *
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2, or (at your option)
  14  * any later version.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * (for example /usr/src/linux/COPYING); if not, write to the Free
  18  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20
  21 #include <linux/slab.h>
  22 #include <linux/delay.h>
  23 #include <linux/blkdev.h>
  24 #include <linux/module.h>
  25 #include <linux/seq_file.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/kthread.h>
  28 #include "md.h"
  29 #include "raid10.h"
  30 #include "raid0.h"
  31 #include "bitmap.h"
  32
  33 /*
  34  * RAID10 provides a combination of RAID0 and RAID1 functionality.
  35  * The layout of data is defined by
  36  *    chunk_size
  37  *    raid_disks
  38  *    near_copies (stored in low byte of layout)
  39  *    far_copies (stored in second byte of layout)
  40  *    far_offset (stored in bit 16 of layout )
  41  *    use_far_sets (stored in bit 17 of layout )
  42  *
  43  * The data to be stored is divided into chunks using chunksize.  Each device
  44  * is divided into far_copies sections.   In each section, chunks are laid out
  45  * in a style similar to raid0, but near_copies copies of each chunk is stored
  46  * (each on a different drive).  The starting device for each section is offset
  47  * near_copies from the starting device of the previous section.  Thus there
  48  * are (near_copies * far_copies) of each chunk, and each is on a different
  49  * drive.  near_copies and far_copies must be at least one, and their product
  50  * is at most raid_disks.
  51  *
  52  * If far_offset is true, then the far_copies are handled a bit differently.
  53  * The copies are still in different stripes, but instead of being very far
  54  * apart on disk, there are adjacent stripes.
  55  *
  56  * The far and offset algorithms are handled slightly differently if
  57  * 'use_far_sets' is true.  In this case, the array's devices are grouped into
  58  * sets that are (near_copies * far_copies) in size.  The far copied stripes
  59  * are still shifted by 'near_copies' devices, but this shifting stays confined
  60  * to the set rather than the entire array.  This is done to improve the number
  61  * of device combinations that can fail without causing the array to fail.
  62  * Example 'far' algorithm w/o 'use_far_sets' (each letter represents a chunk
  63  * on a device):
  64  *    A B C D    A B C D E
  65  *      ...         ...
  66  *    D A B C    E A B C D
  67  * Example 'far' algorithm w/ 'use_far_sets' enabled (sets illustrated w/ []'s):
  68  *    [A B] [C D]    [A B] [C D E]
  69  *    |...| |...|    |...| | ... |
  70  *    [B A] [D C]    [B A] [E C D]
  71  */
  72
  73 /*
  74  * Number of guaranteed r10bios in case of extreme VM load:
  75  */
  76 #define NR_RAID10_BIOS 256
  77
  78 /* when we get a read error on a read-only array, we redirect to another
  79  * device without failing the first device, or trying to over-write to
  80  * correct the read error.  To keep track of bad blocks on a per-bio
  81  * level, we store IO_BLOCKED in the appropriate 'bios' pointer
  82  */
  83 #define IO_BLOCKED ((struct bio *)1)
  84 /* When we successfully write to a known bad-block, we need to remove the
  85  * bad-block marking which must be done from process context.  So we record
  86  * the success by setting devs[n].bio to IO_MADE_GOOD
  87  */
  88 #define IO_MADE_GOOD ((struct bio *)2)
  89
  90 #define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
  91
  92 /* When there are this many requests queued to be written by
  93  * the raid10 thread, we become 'congested' to provide back-pressure
  94  * for writeback.
  95  */
  96 static int max_queued_requests = 1024;
  97
  98 static void allow_barrier(struct r10conf *conf);
  99 static void lower_barrier(struct r10conf *conf);
 100 static int _enough(struct r10conf *conf, int previous, int ignore);
 101 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr,
 102                                 int *skipped);
 103 static void reshape_request_write(struct mddev *mddev, struct r10bio *r10_bio);
 104 static void end_reshape_write(struct bio *bio);
 105 static void end_reshape(struct r10conf *conf);
 106
 107 static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data)
 108 {
 109         struct r10conf *conf = data;
 110         int size = offsetof(struct r10bio, devs[conf->copies]);
 111
 112         /* allocate a r10bio with room for raid_disks entries in the
 113          * bios array */
 114         return kzalloc(size, gfp_flags);
 115 }
 116
 117 static void r10bio_pool_free(void *r10_bio, void *data)
 118 {
 119         kfree(r10_bio);
 120 }
 121
 122 /* Maximum size of each resync request */
 123 #define RESYNC_BLOCK_SIZE (64*1024)
 124 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
 125 /* amount of memory to reserve for resync requests */
 126 #define RESYNC_WINDOW (1024*1024)
 127 /* maximum number of concurrent requests, memory permitting */
 128 #define RESYNC_DEPTH (32*1024*1024/RESYNC_BLOCK_SIZE)
 129
 130 /*
 131  * When performing a resync, we need to read and compare, so
 132  * we need as many pages are there are copies.
 133  * When performing a recovery, we need 2 bios, one for read,
 134  * one for write (we recover only one drive per r10buf)
 135  *
 136  */
 137 static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
 138 {
 139         struct r10conf *conf = data;
 140         struct page *page;
 141         struct r10bio *r10_bio;
 142         struct bio *bio;
 143         int i, j;
 144         int nalloc;
 145
 146         r10_bio = r10bio_pool_alloc(gfp_flags, conf);
 147         if (!r10_bio)
 148                 return NULL;
 149
 150         if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery) ||
 151             test_bit(MD_RECOVERY_RESHAPE, &conf->mddev->recovery))
 152                 nalloc = conf->copies; /* resync */
 153         else
 154                 nalloc = 2; /* recovery */
 155
 156         /*
 157          * Allocate bios.
 158          */
 159         for (j = nalloc ; j-- ; ) {
 160                 bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
 161                 if (!bio)
 162                         goto out_free_bio;
 163                 r10_bio->devs[j].bio = bio;
 164                 if (!conf->have_replacement)
 165                         continue;
 166                 bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
 167                 if (!bio)
 168                         goto out_free_bio;
 169                 r10_bio->devs[j].repl_bio = bio;
 170         }
 171         /*
 172          * Allocate RESYNC_PAGES data pages and attach them
 173          * where needed.
 174          */
 175         for (j = 0 ; j < nalloc; j++) {
 176                 struct bio *rbio = r10_bio->devs[j].repl_bio;
 177                 bio = r10_bio->devs[j].bio;
 178                 for (i = 0; i < RESYNC_PAGES; i++) {
 179                         if (j > 0 && !test_bit(MD_RECOVERY_SYNC,
 180                                                &conf->mddev->recovery)) {
 181                                 /* we can share bv_page's during recovery
 182                                  * and reshape */
 183                                 struct bio *rbio = r10_bio->devs[0].bio;
 184                                 page = rbio->bi_io_vec[i].bv_page;
 185                                 get_page(page);
 186                         } else
 187                                 page = alloc_page(gfp_flags);
 188                         if (unlikely(!page))
 189                                 goto out_free_pages;
 190
 191                         bio->bi_io_vec[i].bv_page = page;
 192                         if (rbio)
 193                                 rbio->bi_io_vec[i].bv_page = page;
 194                 }
 195         }
 196
 197         return r10_bio;
 198
 199 out_free_pages:
 200         for ( ; i > 0 ; i--)
 201                 safe_put_page(bio->bi_io_vec[i-1].bv_page);
 202         while (j--)
 203                 for (i = 0; i < RESYNC_PAGES ; i++)
 204                         safe_put_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page);
 205         j = 0;
 206 out_free_bio:
 207         for ( ; j < nalloc; j++) {
 208                 if (r10_bio->devs[j].bio)
 209                         bio_put(r10_bio->devs[j].bio);
 210                 if (r10_bio->devs[j].repl_bio)
 211                         bio_put(r10_bio->devs[j].repl_bio);
 212         }
 213         r10bio_pool_free(r10_bio, conf);
 214         return NULL;
 215 }
 216
 217 static void r10buf_pool_free(void *__r10_bio, void *data)
 218 {
 219         int i;
 220         struct r10conf *conf = data;
 221         struct r10bio *r10bio = __r10_bio;
 222         int j;
 223
 224         for (j=0; j < conf->copies; j++) {
 225                 struct bio *bio = r10bio->devs[j].bio;
 226                 if (bio) {
 227                         for (i = 0; i < RESYNC_PAGES; i++) {
 228                                 safe_put_page(bio->bi_io_vec[i].bv_page);
 229                                 bio->bi_io_vec[i].bv_page = NULL;
 230                         }
 231                         bio_put(bio);
 232                 }
 233                 bio = r10bio->devs[j].repl_bio;
 234                 if (bio)
 235                         bio_put(bio);
 236         }
 237         r10bio_pool_free(r10bio, conf);
 238 }
 239
 240 static void put_all_bios(struct r10conf *conf, struct r10bio *r10_bio)
 241 {
 242         int i;
 243
 244         for (i = 0; i < conf->copies; i++) {
 245                 struct bio **bio = & r10_bio->devs[i].bio;
 246                 if (!BIO_SPECIAL(*bio))
 247                         bio_put(*bio);
 248                 *bio = NULL;
 249                 bio = &r10_bio->devs[i].repl_bio;
 250                 if (r10_bio->read_slot < 0 && !BIO_SPECIAL(*bio))
 251                         bio_put(*bio);
 252                 *bio = NULL;
 253         }
 254 }
 255
 256 static void free_r10bio(struct r10bio *r10_bio)
 257 {
 258         struct r10conf *conf = r10_bio->mddev->private;
 259
 260         put_all_bios(conf, r10_bio);
 261         mempool_free(r10_bio, conf->r10bio_pool);
 262 }
 263
 264 static void put_buf(struct r10bio *r10_bio)
 265 {
 266         struct r10conf *conf = r10_bio->mddev->private;
 267
 268         mempool_free(r10_bio, conf->r10buf_pool);
 269
 270         lower_barrier(conf);
 271 }
 272
 273 static void reschedule_retry(struct r10bio *r10_bio)
 274 {
 275         unsigned long flags;
 276         struct mddev *mddev = r10_bio->mddev;
 277         struct r10conf *conf = mddev->private;
 278
 279         spin_lock_irqsave(&conf->device_lock, flags);
 280         list_add(&r10_bio->retry_list, &conf->retry_list);
 281         conf->nr_queued ++;
 282         spin_unlock_irqrestore(&conf->device_lock, flags);
 283
 284         /* wake up frozen array... */
 285         wake_up(&conf->wait_barrier);
 286
 287         md_wakeup_thread(mddev->thread);
 288 }
 289
 290 /*
 291  * raid_end_bio_io() is called when we have finished servicing a mirrored
 292  * operation and are ready to return a success/failure code to the buffer
 293  * cache layer.
 294  */
 295 static void raid_end_bio_io(struct r10bio *r10_bio)
 296 {
 297         struct bio *bio = r10_bio->master_bio;
 298         int done;
 299         struct r10conf *conf = r10_bio->mddev->private;
 300
 301         if (bio->bi_phys_segments) {
 302                 unsigned long flags;
 303                 spin_lock_irqsave(&conf->device_lock, flags);
 304                 bio->bi_phys_segments--;
 305                 done = (bio->bi_phys_segments == 0);
 306                 spin_unlock_irqrestore(&conf->device_lock, flags);
 307         } else
 308                 done = 1;
 309         if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
 310                 bio->bi_error = -EIO;
 311         if (done) {
 312                 bio_endio(bio);
 313                 /*
 314                  * Wake up any possible resync thread that waits for the device
 315                  * to go idle.
 316                  */
 317                 allow_barrier(conf);
 318         }
 319         free_r10bio(r10_bio);
 320 }
 321
 322 /*
 323  * Update disk head position estimator based on IRQ completion info.
 324  */
 325 static inline void update_head_pos(int slot, struct r10bio *r10_bio)
 326 {
 327         struct r10conf *conf = r10_bio->mddev->private;
 328
 329         conf->mirrors[r10_bio->devs[slot].devnum].head_position =
 330                 r10_bio->devs[slot].addr + (r10_bio->sectors);
 331 }
 332
 333 /*
 334  * Find the disk number which triggered given bio
 335  */
 336 static int find_bio_disk(struct r10conf *conf, struct r10bio *r10_bio,
 337                          struct bio *bio, int *slotp, int *replp)
 338 {
 339         int slot;
 340         int repl = 0;
 341
 342         for (slot = 0; slot < conf->copies; slot++) {
 343                 if (r10_bio->devs[slot].bio == bio)
 344                         break;
 345                 if (r10_bio->devs[slot].repl_bio == bio) {
 346                         repl = 1;
 347                         break;
 348                 }
 349         }
 350
 351         BUG_ON(slot == conf->copies);
 352         update_head_pos(slot, r10_bio);
 353
 354         if (slotp)
 355                 *slotp = slot;
 356         if (replp)
 357                 *replp = repl;
 358         return r10_bio->devs[slot].devnum;
 359 }
 360
 361 static void raid10_end_read_request(struct bio *bio)
 362 {
 363         int uptodate = !bio->bi_error;
 364         struct r10bio *r10_bio = bio->bi_private;
 365         int slot, dev;
 366         struct md_rdev *rdev;
 367         struct r10conf *conf = r10_bio->mddev->private;
 368
 369         slot = r10_bio->read_slot;
 370         dev = r10_bio->devs[slot].devnum;
 371         rdev = r10_bio->devs[slot].rdev;
 372         /*
 373          * this branch is our 'one mirror IO has finished' event handler:
 374          */
 375         update_head_pos(slot, r10_bio);
 376
 377         if (uptodate) {
 378                 /*
 379                  * Set R10BIO_Uptodate in our master bio, so that
 380                  * we will return a good error code to the higher
 381                  * levels even if IO on some other mirrored buffer fails.
 382                  *
 383                  * The 'master' represents the composite IO operation to
 384                  * user-side. So if something waits for IO, then it will
 385                  * wait for the 'master' bio.
 386                  */
 387                 set_bit(R10BIO_Uptodate, &r10_bio->state);
 388         } else {
 389                 /* If all other devices that store this block have
 390                  * failed, we want to return the error upwards rather
 391                  * than fail the last device.  Here we redefine
 392                  * "uptodate" to mean "Don't want to retry"
 393                  */
 394                 if (!_enough(conf, test_bit(R10BIO_Previous, &r10_bio->state),
 395                              rdev->raid_disk))
 396                         uptodate = 1;
 397         }
 398         if (uptodate) {
 399                 raid_end_bio_io(r10_bio);
 400                 rdev_dec_pending(rdev, conf->mddev);
 401         } else {
 402                 /*
 403                  * oops, read error - keep the refcount on the rdev
 404                  */
 405                 char b[BDEVNAME_SIZE];
 406                 printk_ratelimited(KERN_ERR
 407                                    "md/raid10:%s: %s: rescheduling sector %llu\n",
 408                                    mdname(conf->mddev),
 409                                    bdevname(rdev->bdev, b),
 410                                    (unsigned long long)r10_bio->sector);
 411                 set_bit(R10BIO_ReadError, &r10_bio->state);
 412                 reschedule_retry(r10_bio);
 413         }
 414 }
 415
 416 static void close_write(struct r10bio *r10_bio)
 417 {
 418         /* clear the bitmap if all writes complete successfully */
 419         bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector,
 420                         r10_bio->sectors,
 421                         !test_bit(R10BIO_Degraded, &r10_bio->state),
 422                         0);
 423         md_write_end(r10_bio->mddev);
 424 }
 425
 426 static void one_write_done(struct r10bio *r10_bio)
 427 {
 428         if (atomic_dec_and_test(&r10_bio->remaining)) {
 429                 if (test_bit(R10BIO_WriteError, &r10_bio->state))
 430                         reschedule_retry(r10_bio);
 431                 else {
 432                         close_write(r10_bio);
 433                         if (test_bit(R10BIO_MadeGood, &r10_bio->state))
 434                                 reschedule_retry(r10_bio);
 435                         else
 436                                 raid_end_bio_io(r10_bio);
 437                 }
 438         }
 439 }
 440
 441 static void raid10_end_write_request(struct bio *bio)
 442 {
 443         struct r10bio *r10_bio = bio->bi_private;
 444         int dev;
 445         int dec_rdev = 1;
 446         struct r10conf *conf = r10_bio->mddev->private;
 447         int slot, repl;
 448         struct md_rdev *rdev = NULL;
 449
 450         dev = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
 451
 452         if (repl)
 453                 rdev = conf->mirrors[dev].replacement;
 454         if (!rdev) {
 455                 smp_rmb();
 456                 repl = 0;
 457                 rdev = conf->mirrors[dev].rdev;
 458         }
 459         /*
 460          * this branch is our 'one mirror IO has finished' event handler:
 461          */
 462         if (bio->bi_error) {
 463                 if (repl)
 464                         /* Never record new bad blocks to replacement,
 465                          * just fail it.
 466                          */
 467                         md_error(rdev->mddev, rdev);
 468                 else {
 469                         set_bit(WriteErrorSeen, &rdev->flags);
 470                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
 471                                 set_bit(MD_RECOVERY_NEEDED,
 472                                         &rdev->mddev->recovery);
 473                         set_bit(R10BIO_WriteError, &r10_bio->state);
 474                         dec_rdev = 0;
 475                 }
 476         } else {
 477                 /*
 478                  * Set R10BIO_Uptodate in our master bio, so that
 479                  * we will return a good error code for to the higher
 480                  * levels even if IO on some other mirrored buffer fails.
 481                  *
 482                  * The 'master' represents the composite IO operation to
 483                  * user-side. So if something waits for IO, then it will
 484                  * wait for the 'master' bio.
 485                  */
 486                 sector_t first_bad;
 487                 int bad_sectors;
 488
 489                 /*
 490                  * Do not set R10BIO_Uptodate if the current device is
 491                  * rebuilding or Faulty. This is because we cannot use
 492                  * such device for properly reading the data back (we could
 493                  * potentially use it, if the current write would have felt
 494                  * before rdev->recovery_offset, but for simplicity we don't
 495                  * check this here.
 496                  */
 497                 if (test_bit(In_sync, &rdev->flags) &&
 498                     !test_bit(Faulty, &rdev->flags))
 499                         set_bit(R10BIO_Uptodate, &r10_bio->state);
 500
 501                 /* Maybe we can clear some bad blocks. */
 502                 if (is_badblock(rdev,
 503                                 r10_bio->devs[slot].addr,
 504                                 r10_bio->sectors,
 505                                 &first_bad, &bad_sectors)) {
 506                         bio_put(bio);
 507                         if (repl)
 508                                 r10_bio->devs[slot].repl_bio = IO_MADE_GOOD;
 509                         else
 510                                 r10_bio->devs[slot].bio = IO_MADE_GOOD;
 511                         dec_rdev = 0;
 512                         set_bit(R10BIO_MadeGood, &r10_bio->state);
 513                 }
 514         }
 515
 516         /*
 517          *
 518          * Let's see if all mirrored write operations have finished
 519          * already.
 520          */
 521         one_write_done(r10_bio);
 522         if (dec_rdev)
 523                 rdev_dec_pending(rdev, conf->mddev);
 524 }
 525
 526 /*
 527  * RAID10 layout manager
 528  * As well as the chunksize and raid_disks count, there are two
 529  * parameters: near_copies and far_copies.
 530  * near_copies * far_copies must be <= raid_disks.
 531  * Normally one of these will be 1.
 532  * If both are 1, we get raid0.
 533  * If near_copies == raid_disks, we get raid1.
 534  *
 535  * Chunks are laid out in raid0 style with near_copies copies of the
 536  * first chunk, followed by near_copies copies of the next chunk and
 537  * so on.
 538  * If far_copies > 1, then after 1/far_copies of the array has been assigned
 539  * as described above, we start again with a device offset of near_copies.
 540  * So we effectively have another copy of the whole array further down all
 541  * the drives, but with blocks on different drives.
 542  * With this layout, and block is never stored twice on the one device.
 543  *
 544  * raid10_find_phys finds the sector offset of a given virtual sector
 545  * on each device that it is on.
 546  *
 547  * raid10_find_virt does the reverse mapping, from a device and a
 548  * sector offset to a virtual address
 549  */
 550
 551 static void __raid10_find_phys(struct geom *geo, struct r10bio *r10bio)
 552 {
 553         int n,f;
 554         sector_t sector;
 555         sector_t chunk;
 556         sector_t stripe;
 557         int dev;
 558         int slot = 0;
 559         int last_far_set_start, last_far_set_size;
 560
 561         last_far_set_start = (geo->raid_disks / geo->far_set_size) - 1;
 562         last_far_set_start *= geo->far_set_size;
 563
 564         last_far_set_size = geo->far_set_size;
 565         last_far_set_size += (geo->raid_disks % geo->far_set_size);
 566
 567         /* now calculate first sector/dev */
 568         chunk = r10bio->sector >> geo->chunk_shift;
 569         sector = r10bio->sector & geo->chunk_mask;
 570
 571         chunk *= geo->near_copies;
 572         stripe = chunk;
 573         dev = sector_div(stripe, geo->raid_disks);
 574         if (geo->far_offset)
 575                 stripe *= geo->far_copies;
 576
 577         sector += stripe << geo->chunk_shift;
 578
 579         /* and calculate all the others */
 580         for (n = 0; n < geo->near_copies; n++) {
 581                 int d = dev;
 582                 int set;
 583                 sector_t s = sector;
 584                 r10bio->devs[slot].devnum = d;
 585                 r10bio->devs[slot].addr = s;
 586                 slot++;
 587
 588                 for (f = 1; f < geo->far_copies; f++) {
 589                         set = d / geo->far_set_size;
 590                         d += geo->near_copies;
 591
 592                         if ((geo->raid_disks % geo->far_set_size) &&
 593                             (d > last_far_set_start)) {
 594                                 d -= last_far_set_start;
 595                                 d %= last_far_set_size;
 596                                 d += last_far_set_start;
 597                         } else {
 598                                 d %= geo->far_set_size;
 599                                 d += geo->far_set_size * set;
 600                         }
 601                         s += geo->stride;
 602                         r10bio->devs[slot].devnum = d;
 603                         r10bio->devs[slot].addr = s;
 604                         slot++;
 605                 }
 606                 dev++;
 607                 if (dev >= geo->raid_disks) {
 608                         dev = 0;
 609                         sector += (geo->chunk_mask + 1);
 610                 }
 611         }
 612 }
 613
 614 static void raid10_find_phys(struct r10conf *conf, struct r10bio *r10bio)
 615 {
 616         struct geom *geo = &conf->geo;
 617
 618         if (conf->reshape_progress != MaxSector &&
 619             ((r10bio->sector >= conf->reshape_progress) !=
 620              conf->mddev->reshape_backwards)) {
 621                 set_bit(R10BIO_Previous, &r10bio->state);
 622                 geo = &conf->prev;
 623         } else
 624                 clear_bit(R10BIO_Previous, &r10bio->state);
 625
 626         __raid10_find_phys(geo, r10bio);
 627 }
 628
 629 static sector_t raid10_find_virt(struct r10conf *conf, sector_t sector, int dev)
 630 {
 631         sector_t offset, chunk, vchunk;
 632         /* Never use conf->prev as this is only called during resync
 633          * or recovery, so reshape isn't happening
 634          */
 635         struct geom *geo = &conf->geo;
 636         int far_set_start = (dev / geo->far_set_size) * geo->far_set_size;
 637         int far_set_size = geo->far_set_size;
 638         int last_far_set_start;
 639
 640         if (geo->raid_disks % geo->far_set_size) {
 641                 last_far_set_start = (geo->raid_disks / geo->far_set_size) - 1;
 642                 last_far_set_start *= geo->far_set_size;
 643
 644                 if (dev >= last_far_set_start) {
 645                         far_set_size = geo->far_set_size;
 646                         far_set_size += (geo->raid_disks % geo->far_set_size);
 647                         far_set_start = last_far_set_start;
 648                 }
 649         }
 650
 651         offset = sector & geo->chunk_mask;
 652         if (geo->far_offset) {
 653                 int fc;
 654                 chunk = sector >> geo->chunk_shift;
 655                 fc = sector_div(chunk, geo->far_copies);
 656                 dev -= fc * geo->near_copies;
 657                 if (dev < far_set_start)
 658                         dev += far_set_size;
 659         } else {
 660                 while (sector >= geo->stride) {
 661                         sector -= geo->stride;
 662                         if (dev < (geo->near_copies + far_set_start))
 663                                 dev += far_set_size - geo->near_copies;
 664                         else
 665                                 dev -= geo->near_copies;
 666                 }
 667                 chunk = sector >> geo->chunk_shift;
 668         }
 669         vchunk = chunk * geo->raid_disks + dev;
 670         sector_div(vchunk, geo->near_copies);
 671         return (vchunk << geo->chunk_shift) + offset;
 672 }
 673
 674 /*
 675  * This routine returns the disk from which the requested read should
 676  * be done. There is a per-array 'next expected sequential IO' sector
 677  * number - if this matches on the next IO then we use the last disk.
 678  * There is also a per-disk 'last know head position' sector that is
 679  * maintained from IRQ contexts, both the normal and the resync IO
 680  * completion handlers update this position correctly. If there is no
 681  * perfect sequential match then we pick the disk whose head is closest.
 682  *
 683  * If there are 2 mirrors in the same 2 devices, performance degrades
 684  * because position is mirror, not device based.
 685  *
 686  * The rdev for the device selected will have nr_pending incremented.
 687  */
 688
 689 /*
 690  * FIXME: possibly should rethink readbalancing and do it differently
 691  * depending on near_copies / far_copies geometry.
 692  */
 693 static struct md_rdev *read_balance(struct r10conf *conf,
 694                                     struct r10bio *r10_bio,
 695                                     int *max_sectors)
 696 {
 697         const sector_t this_sector = r10_bio->sector;
 698         int disk, slot;
 699         int sectors = r10_bio->sectors;
 700         int best_good_sectors;
 701         sector_t new_distance, best_dist;
 702         struct md_rdev *best_rdev, *rdev = NULL;
 703         int do_balance;
 704         int best_slot;
 705         struct geom *geo = &conf->geo;
 706
 707         raid10_find_phys(conf, r10_bio);
 708         rcu_read_lock();
 709 retry:
 710         sectors = r10_bio->sectors;
 711         best_slot = -1;
 712         best_rdev = NULL;
 713         best_dist = MaxSector;
 714         best_good_sectors = 0;
 715         do_balance = 1;
 716         /*
 717          * Check if we can balance. We can balance on the whole
 718          * device if no resync is going on (recovery is ok), or below
 719          * the resync window. We take the first readable disk when
 720          * above the resync window.
 721          */
 722         if (conf->mddev->recovery_cp < MaxSector
 723             && (this_sector + sectors >= conf->next_resync))
 724                 do_balance = 0;
 725
 726         for (slot = 0; slot < conf->copies ; slot++) {
 727                 sector_t first_bad;
 728                 int bad_sectors;
 729                 sector_t dev_sector;
 730
 731                 if (r10_bio->devs[slot].bio == IO_BLOCKED)
 732                         continue;
 733                 disk = r10_bio->devs[slot].devnum;
 734                 rdev = rcu_dereference(conf->mirrors[disk].replacement);
 735                 if (rdev == NULL || test_bit(Faulty, &rdev->flags) ||
 736                     r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
 737                         rdev = rcu_dereference(conf->mirrors[disk].rdev);
 738                 if (rdev == NULL ||
 739                     test_bit(Faulty, &rdev->flags))
 740                         continue;
 741                 if (!test_bit(In_sync, &rdev->flags) &&
 742                     r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
 743                         continue;
 744
 745                 dev_sector = r10_bio->devs[slot].addr;
 746                 if (is_badblock(rdev, dev_sector, sectors,
 747                                 &first_bad, &bad_sectors)) {
 748                         if (best_dist < MaxSector)
 749                                 /* Already have a better slot */
 750                                 continue;
 751                         if (first_bad <= dev_sector) {
 752                                 /* Cannot read here.  If this is the
 753                                  * 'primary' device, then we must not read
 754                                  * beyond 'bad_sectors' from another device.
 755                                  */
 756                                 bad_sectors -= (dev_sector - first_bad);
 757                                 if (!do_balance && sectors > bad_sectors)
 758                                         sectors = bad_sectors;
 759                                 if (best_good_sectors > sectors)
 760                                         best_good_sectors = sectors;
 761                         } else {
 762                                 sector_t good_sectors =
 763                                         first_bad - dev_sector;
 764                                 if (good_sectors > best_good_sectors) {
 765                                         best_good_sectors = good_sectors;
 766                                         best_slot = slot;
 767                                         best_rdev = rdev;
 768                                 }
 769                                 if (!do_balance)
 770                                         /* Must read from here */
 771                                         break;
 772                         }
 773                         continue;
 774                 } else
 775                         best_good_sectors = sectors;
 776
 777                 if (!do_balance)
 778                         break;
 779
 780                 /* This optimisation is debatable, and completely destroys
 781                  * sequential read speed for 'far copies' arrays.  So only
 782                  * keep it for 'near' arrays, and review those later.
 783                  */
 784                 if (geo->near_copies > 1 && !atomic_read(&rdev->nr_pending))
 785                         break;
 786
 787                 /* for far > 1 always use the lowest address */
 788                 if (geo->far_copies > 1)
 789                         new_distance = r10_bio->devs[slot].addr;
 790                 else
 791                         new_distance = abs(r10_bio->devs[slot].addr -
 792                                            conf->mirrors[disk].head_position);
 793                 if (new_distance < best_dist) {
 794                         best_dist = new_distance;
 795                         best_slot = slot;
 796                         best_rdev = rdev;
 797                 }
 798         }
 799         if (slot >= conf->copies) {
 800                 slot = best_slot;
 801                 rdev = best_rdev;
 802         }
 803
 804         if (slot >= 0) {
 805                 atomic_inc(&rdev->nr_pending);
 806                 if (test_bit(Faulty, &rdev->flags)) {
 807                         /* Cannot risk returning a device that failed
 808                          * before we inc'ed nr_pending
 809                          */
 810                         rdev_dec_pending(rdev, conf->mddev);
 811                         goto retry;
 812                 }
 813                 r10_bio->read_slot = slot;
 814         } else
 815                 rdev = NULL;
 816         rcu_read_unlock();
 817         *max_sectors = best_good_sectors;
 818
 819         return rdev;
 820 }
 821
 822 static int raid10_congested(struct mddev *mddev, int bits)
 823 {
 824         struct r10conf *conf = mddev->private;
 825         int i, ret = 0;
 826
 827         if ((bits & (1 << WB_async_congested)) &&
 828             conf->pending_count >= max_queued_requests)
 829                 return 1;
 830
 831         rcu_read_lock();
 832         for (i = 0;
 833              (i < conf->geo.raid_disks || i < conf->prev.raid_disks)
 834                      && ret == 0;
 835              i++) {
 836                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
 837                 if (rdev && !test_bit(Faulty, &rdev->flags)) {
 838                         struct request_queue *q = bdev_get_queue(rdev->bdev);
 839
 840                         ret |= bdi_congested(&q->backing_dev_info, bits);
 841                 }
 842         }
 843         rcu_read_unlock();
 844         return ret;
 845 }
 846
 847 static void flush_pending_writes(struct r10conf *conf)
 848 {
 849         /* Any writes that have been queued but are awaiting
 850          * bitmap updates get flushed here.
 851          */
 852         spin_lock_irq(&conf->device_lock);
 853
 854         if (conf->pending_bio_list.head) {
 855                 struct bio *bio;
 856                 bio = bio_list_get(&conf->pending_bio_list);
 857                 conf->pending_count = 0;
 858                 spin_unlock_irq(&conf->device_lock);
 859                 /* flush any pending bitmap writes to disk
 860                  * before proceeding w/ I/O */
 861                 bitmap_unplug(conf->mddev->bitmap);
 862                 wake_up(&conf->wait_barrier);
 863
 864                 while (bio) { /* submit pending writes */
 865                         struct bio *next = bio->bi_next;
 866                         bio->bi_next = NULL;
 867                         if (unlikely((bio->bi_rw & REQ_DISCARD) &&
 868                             !blk_queue_discard(bdev_get_queue(bio->bi_bdev))))
 869                                 /* Just ignore it */
 870                                 bio_endio(bio);
 871                         else
 872                                 generic_make_request(bio);
 873                         bio = next;
 874                 }
 875         } else
 876                 spin_unlock_irq(&conf->device_lock);
 877 }
 878
 879 /* Barriers....
 880  * Sometimes we need to suspend IO while we do something else,
 881  * either some resync/recovery, or reconfigure the array.
 882  * To do this we raise a 'barrier'.
 883  * The 'barrier' is a counter that can be raised multiple times
 884  * to count how many activities are happening which preclude
 885  * normal IO.
 886  * We can only raise the barrier if there is no pending IO.
 887  * i.e. if nr_pending == 0.
 888  * We choose only to raise the barrier if no-one is waiting for the
 889  * barrier to go down.  This means that as soon as an IO request
 890  * is ready, no other operations which require a barrier will start
 891  * until the IO request has had a chance.
 892  *
 893  * So: regular IO calls 'wait_barrier'.  When that returns there
 894  *    is no backgroup IO happening,  It must arrange to call
 895  *    allow_barrier when it has finished its IO.
 896  * backgroup IO calls must call raise_barrier.  Once that returns
 897  *    there is no normal IO happeing.  It must arrange to call
 898  *    lower_barrier when the particular background IO completes.
 899  */
 900
 901 static void raise_barrier(struct r10conf *conf, int force)
 902 {
 903         BUG_ON(force && !conf->barrier);
 904         spin_lock_irq(&conf->resync_lock);
 905
 906         /* Wait until no block IO is waiting (unless 'force') */
 907         wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting,
 908                             conf->resync_lock);
 909
 910         /* block any new IO from starting */
 911         conf->barrier++;
 912
 913         /* Now wait for all pending IO to complete */
 914         wait_event_lock_irq(conf->wait_barrier,
 915                             !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
 916                             conf->resync_lock);
 917
 918         spin_unlock_irq(&conf->resync_lock);
 919 }
 920
 921 static void lower_barrier(struct r10conf *conf)
 922 {
 923         unsigned long flags;
 924         spin_lock_irqsave(&conf->resync_lock, flags);
 925         conf->barrier--;
 926         spin_unlock_irqrestore(&conf->resync_lock, flags);
 927         wake_up(&conf->wait_barrier);
 928 }
 929
 930 static void wait_barrier(struct r10conf *conf)
 931 {
 932         spin_lock_irq(&conf->resync_lock);
 933         if (conf->barrier) {
 934                 conf->nr_waiting++;
 935                 /* Wait for the barrier to drop.
 936                  * However if there are already pending
 937                  * requests (preventing the barrier from
 938                  * rising completely), and the
 939                  * pre-process bio queue isn't empty,
 940                  * then don't wait, as we need to empty
 941                  * that queue to get the nr_pending
 942                  * count down.
 943                  */
 944                 wait_event_lock_irq(conf->wait_barrier,
 945                                     !conf->barrier ||
 946                                     (conf->nr_pending &&
 947                                      current->bio_list &&
 948                                      !bio_list_empty(current->bio_list)),
 949                                     conf->resync_lock);
 950                 conf->nr_waiting--;
 951         }
 952         conf->nr_pending++;
 953         spin_unlock_irq(&conf->resync_lock);
 954 }
 955
 956 static void allow_barrier(struct r10conf *conf)
 957 {
 958         unsigned long flags;
 959         spin_lock_irqsave(&conf->resync_lock, flags);
 960         conf->nr_pending--;
 961         spin_unlock_irqrestore(&conf->resync_lock, flags);
 962         wake_up(&conf->wait_barrier);
 963 }
 964
 965 static void freeze_array(struct r10conf *conf, int extra)
 966 {
 967         /* stop syncio and normal IO and wait for everything to
 968          * go quiet.
 969          * We increment barrier and nr_waiting, and then
 970          * wait until nr_pending match nr_queued+extra
 971          * This is called in the context of one normal IO request
 972          * that has failed. Thus any sync request that might be pending
 973          * will be blocked by nr_pending, and we need to wait for
 974          * pending IO requests to complete or be queued for re-try.
 975          * Thus the number queued (nr_queued) plus this request (extra)
 976          * must match the number of pending IOs (nr_pending) before
 977          * we continue.
 978          */
 979         spin_lock_irq(&conf->resync_lock);
 980         conf->barrier++;
 981         conf->nr_waiting++;
 982         wait_event_lock_irq_cmd(conf->wait_barrier,
 983                                 conf->nr_pending == conf->nr_queued+extra,
 984                                 conf->resync_lock,
 985                                 flush_pending_writes(conf));
 986
 987         spin_unlock_irq(&conf->resync_lock);
 988 }
 989
 990 static void unfreeze_array(struct r10conf *conf)
 991 {
 992         /* reverse the effect of the freeze */
 993         spin_lock_irq(&conf->resync_lock);
 994         conf->barrier--;
 995         conf->nr_waiting--;
 996         wake_up(&conf->wait_barrier);
 997         spin_unlock_irq(&conf->resync_lock);
 998 }
 999
1000 static sector_t choose_data_offset(struct r10bio *r10_bio,
1001                                    struct md_rdev *rdev)
1002 {
1003         if (!test_bit(MD_RECOVERY_RESHAPE, &rdev->mddev->recovery) ||
1004             test_bit(R10BIO_Previous, &r10_bio->state))
1005                 return rdev->data_offset;
1006         else
1007                 return rdev->new_data_offset;
1008 }
1009
1010 struct raid10_plug_cb {
1011         struct blk_plug_cb      cb;
1012         struct bio_list         pending;
1013         int                     pending_cnt;
1014 };
1015
1016 static void raid10_unplug(struct blk_plug_cb *cb, bool from_schedule)
1017 {
1018         struct raid10_plug_cb *plug = container_of(cb, struct raid10_plug_cb,
1019                                                    cb);
1020         struct mddev *mddev = plug->cb.data;
1021         struct r10conf *conf = mddev->private;
1022         struct bio *bio;
1023
1024         if (from_schedule || current->bio_list) {
1025                 spin_lock_irq(&conf->device_lock);
1026                 bio_list_merge(&conf->pending_bio_list, &plug->pending);
1027                 conf->pending_count += plug->pending_cnt;
1028                 spin_unlock_irq(&conf->device_lock);
1029                 wake_up(&conf->wait_barrier);
1030                 md_wakeup_thread(mddev->thread);
1031                 kfree(plug);
1032                 return;
1033         }
1034
1035         /* we aren't scheduling, so we can do the write-out directly. */
1036         bio = bio_list_get(&plug->pending);
1037         bitmap_unplug(mddev->bitmap);
1038         wake_up(&conf->wait_barrier);
1039
1040         while (bio) { /* submit pending writes */
1041                 struct bio *next = bio->bi_next;
1042                 bio->bi_next = NULL;
1043                 if (unlikely((bio->bi_rw & REQ_DISCARD) &&
1044                     !blk_queue_discard(bdev_get_queue(bio->bi_bdev))))
1045                         /* Just ignore it */
1046                         bio_endio(bio);
1047                 else
1048                         generic_make_request(bio);
1049                 bio = next;
1050         }
1051         kfree(plug);
1052 }
1053
1054 static void __make_request(struct mddev *mddev, struct bio *bio)
1055 {
1056         struct r10conf *conf = mddev->private;
1057         struct r10bio *r10_bio;
1058         struct bio *read_bio;
1059         int i;
1060         const int rw = bio_data_dir(bio);
1061         const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
1062         const unsigned long do_fua = (bio->bi_rw & REQ_FUA);
1063         const unsigned long do_discard = (bio->bi_rw
1064                                           & (REQ_DISCARD | REQ_SECURE));
1065         const unsigned long do_same = (bio->bi_rw & REQ_WRITE_SAME);
1066         unsigned long flags;
1067         struct md_rdev *blocked_rdev;
1068         struct blk_plug_cb *cb;
1069         struct raid10_plug_cb *plug = NULL;
1070         int sectors_handled;
1071         int max_sectors;
1072         int sectors;
1073
1074         /*
1075          * Register the new request and wait if the reconstruction
1076          * thread has put up a bar for new requests.
1077          * Continue immediately if no resync is active currently.
1078          */
1079         wait_barrier(conf);
1080
1081         sectors = bio_sectors(bio);
1082         while (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
1083             bio->bi_iter.bi_sector < conf->reshape_progress &&
1084             bio->bi_iter.bi_sector + sectors > conf->reshape_progress) {
1085                 /* IO spans the reshape position.  Need to wait for
1086                  * reshape to pass
1087                  */
1088                 allow_barrier(conf);
1089                 wait_event(conf->wait_barrier,
1090                            conf->reshape_progress <= bio->bi_iter.bi_sector ||
1091                            conf->reshape_progress >= bio->bi_iter.bi_sector +
1092                            sectors);
1093                 wait_barrier(conf);
1094         }
1095         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
1096             bio_data_dir(bio) == WRITE &&
1097             (mddev->reshape_backwards
1098              ? (bio->bi_iter.bi_sector < conf->reshape_safe &&
1099                 bio->bi_iter.bi_sector + sectors > conf->reshape_progress)
1100              : (bio->bi_iter.bi_sector + sectors > conf->reshape_safe &&
1101                 bio->bi_iter.bi_sector < conf->reshape_progress))) {
1102                 /* Need to update reshape_position in metadata */
1103                 mddev->reshape_position = conf->reshape_progress;
1104                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1105                 set_bit(MD_CHANGE_PENDING, &mddev->flags);
1106                 md_wakeup_thread(mddev->thread);
1107                 wait_event(mddev->sb_wait,
1108                            !test_bit(MD_CHANGE_PENDING, &mddev->flags));
1109
1110                 conf->reshape_safe = mddev->reshape_position;
1111         }
1112
1113         r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
1114
1115         r10_bio->master_bio = bio;
1116         r10_bio->sectors = sectors;
1117
1118         r10_bio->mddev = mddev;
1119         r10_bio->sector = bio->bi_iter.bi_sector;
1120         r10_bio->state = 0;
1121
1122         /* We might need to issue multiple reads to different
1123          * devices if there are bad blocks around, so we keep
1124          * track of the number of reads in bio->bi_phys_segments.
1125          * If this is 0, there is only one r10_bio and no locking
1126          * will be needed when the request completes.  If it is
1127          * non-zero, then it is the number of not-completed requests.
1128          */
1129         bio->bi_phys_segments = 0;
1130         bio_clear_flag(bio, BIO_SEG_VALID);
1131
1132         if (rw == READ) {
1133                 /*
1134                  * read balancing logic:
1135                  */
1136                 struct md_rdev *rdev;
1137                 int slot;
1138
1139 read_again:
1140                 rdev = read_balance(conf, r10_bio, &max_sectors);
1141                 if (!rdev) {
1142                         raid_end_bio_io(r10_bio);
1143                         return;
1144                 }
1145                 slot = r10_bio->read_slot;
1146
1147                 read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1148                 bio_trim(read_bio, r10_bio->sector - bio->bi_iter.bi_sector,
1149                          max_sectors);
1150
1151                 r10_bio->devs[slot].bio = read_bio;
1152                 r10_bio->devs[slot].rdev = rdev;
1153
1154                 read_bio->bi_iter.bi_sector = r10_bio->devs[slot].addr +
1155                         choose_data_offset(r10_bio, rdev);
1156                 read_bio->bi_bdev = rdev->bdev;
1157                 read_bio->bi_end_io = raid10_end_read_request;
1158                 read_bio->bi_rw = READ | do_sync;
1159                 read_bio->bi_private = r10_bio;
1160
1161                 if (max_sectors < r10_bio->sectors) {
1162                         /* Could not read all from this device, so we will
1163                          * need another r10_bio.
1164                          */
1165                         sectors_handled = (r10_bio->sector + max_sectors
1166                                            - bio->bi_iter.bi_sector);
1167                         r10_bio->sectors = max_sectors;
1168                         spin_lock_irq(&conf->device_lock);
1169                         if (bio->bi_phys_segments == 0)
1170                                 bio->bi_phys_segments = 2;
1171                         else
1172                                 bio->bi_phys_segments++;
1173                         spin_unlock_irq(&conf->device_lock);
1174                         /* Cannot call generic_make_request directly
1175                          * as that will be queued in __generic_make_request
1176                          * and subsequent mempool_alloc might block
1177                          * waiting for it.  so hand bio over to raid10d.
1178                          */
1179                         reschedule_retry(r10_bio);
1180
1181                         r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
1182
1183                         r10_bio->master_bio = bio;
1184                         r10_bio->sectors = bio_sectors(bio) - sectors_handled;
1185                         r10_bio->state = 0;
1186                         r10_bio->mddev = mddev;
1187                         r10_bio->sector = bio->bi_iter.bi_sector +
1188                                 sectors_handled;
1189                         goto read_again;
1190                 } else
1191                         generic_make_request(read_bio);
1192                 return;
1193         }
1194
1195         /*
1196          * WRITE:
1197          */
1198         if (conf->pending_count >= max_queued_requests) {
1199                 md_wakeup_thread(mddev->thread);
1200                 wait_event(conf->wait_barrier,
1201                            conf->pending_count < max_queued_requests);
1202         }
1203         /* first select target devices under rcu_lock and
1204          * inc refcount on their rdev.  Record them by setting
1205          * bios[x] to bio
1206          * If there are known/acknowledged bad blocks on any device
1207          * on which we have seen a write error, we want to avoid
1208          * writing to those blocks.  This potentially requires several
1209          * writes to write around the bad blocks.  Each set of writes
1210          * gets its own r10_bio with a set of bios attached.  The number
1211          * of r10_bios is recored in bio->bi_phys_segments just as with
1212          * the read case.
1213          */
1214
1215         r10_bio->read_slot = -1; /* make sure repl_bio gets freed */
1216         raid10_find_phys(conf, r10_bio);
1217 retry_write:
1218         blocked_rdev = NULL;
1219         rcu_read_lock();
1220         max_sectors = r10_bio->sectors;
1221
1222         for (i = 0;  i < conf->copies; i++) {
1223                 int d = r10_bio->devs[i].devnum;
1224                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[d].rdev);
1225                 struct md_rdev *rrdev = rcu_dereference(
1226                         conf->mirrors[d].replacement);
1227                 if (rdev == rrdev)
1228                         rrdev = NULL;
1229                 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
1230                         atomic_inc(&rdev->nr_pending);
1231                         blocked_rdev = rdev;
1232                         break;
1233                 }
1234                 if (rrdev && unlikely(test_bit(Blocked, &rrdev->flags))) {
1235                         atomic_inc(&rrdev->nr_pending);
1236                         blocked_rdev = rrdev;
1237                         break;
1238                 }
1239                 if (rdev && (test_bit(Faulty, &rdev->flags)))
1240                         rdev = NULL;
1241                 if (rrdev && (test_bit(Faulty, &rrdev->flags)))
1242                         rrdev = NULL;
1243
1244                 r10_bio->devs[i].bio = NULL;
1245                 r10_bio->devs[i].repl_bio = NULL;
1246
1247                 if (!rdev && !rrdev) {
1248                         set_bit(R10BIO_Degraded, &r10_bio->state);
1249                         continue;
1250                 }
1251                 if (rdev && test_bit(WriteErrorSeen, &rdev->flags)) {
1252                         sector_t first_bad;
1253                         sector_t dev_sector = r10_bio->devs[i].addr;
1254                         int bad_sectors;
1255                         int is_bad;
1256
1257                         is_bad = is_badblock(rdev, dev_sector,
1258                                              max_sectors,
1259                                              &first_bad, &bad_sectors);
1260                         if (is_bad < 0) {
1261                                 /* Mustn't write here until the bad block
1262                                  * is acknowledged
1263                                  */
1264                                 atomic_inc(&rdev->nr_pending);
1265                                 set_bit(BlockedBadBlocks, &rdev->flags);
1266                                 blocked_rdev = rdev;
1267                                 break;
1268                         }
1269                         if (is_bad && first_bad <= dev_sector) {
1270                                 /* Cannot write here at all */
1271                                 bad_sectors -= (dev_sector - first_bad);
1272                                 if (bad_sectors < max_sectors)
1273                                         /* Mustn't write more than bad_sectors
1274                                          * to other devices yet
1275                                          */
1276                                         max_sectors = bad_sectors;
1277                                 /* We don't set R10BIO_Degraded as that
1278                                  * only applies if the disk is missing,
1279                                  * so it might be re-added, and we want to
1280                                  * know to recover this chunk.
1281                                  * In this case the device is here, and the
1282                                  * fact that this chunk is not in-sync is
1283                                  * recorded in the bad block log.
1284                                  */
1285                                 continue;
1286                         }
1287                         if (is_bad) {
1288                                 int good_sectors = first_bad - dev_sector;
1289                                 if (good_sectors < max_sectors)
1290                                         max_sectors = good_sectors;
1291                         }
1292                 }
1293                 if (rdev) {
1294                         r10_bio->devs[i].bio = bio;
1295                         atomic_inc(&rdev->nr_pending);
1296                 }
1297                 if (rrdev) {
1298                         r10_bio->devs[i].repl_bio = bio;
1299                         atomic_inc(&rrdev->nr_pending);
1300                 }
1301         }
1302         rcu_read_unlock();
1303
1304         if (unlikely(blocked_rdev)) {
1305                 /* Have to wait for this device to get unblocked, then retry */
1306                 int j;
1307                 int d;
1308
1309                 for (j = 0; j < i; j++) {
1310                         if (r10_bio->devs[j].bio) {
1311                                 d = r10_bio->devs[j].devnum;
1312                                 rdev_dec_pending(conf->mirrors[d].rdev, mddev);
1313                         }
1314                         if (r10_bio->devs[j].repl_bio) {
1315                                 struct md_rdev *rdev;
1316                                 d = r10_bio->devs[j].devnum;
1317                                 rdev = conf->mirrors[d].replacement;
1318                                 if (!rdev) {
1319                                         /* Race with remove_disk */
1320                                         smp_mb();
1321                                         rdev = conf->mirrors[d].rdev;
1322                                 }
1323                                 rdev_dec_pending(rdev, mddev);
1324                         }
1325                 }
1326                 allow_barrier(conf);
1327                 md_wait_for_blocked_rdev(blocked_rdev, mddev);
1328                 wait_barrier(conf);
1329                 goto retry_write;
1330         }
1331
1332         if (max_sectors < r10_bio->sectors) {
1333                 /* We are splitting this into multiple parts, so
1334                  * we need to prepare for allocating another r10_bio.
1335                  */
1336                 r10_bio->sectors = max_sectors;
1337                 spin_lock_irq(&conf->device_lock);
1338                 if (bio->bi_phys_segments == 0)
1339                         bio->bi_phys_segments = 2;
1340                 else
1341                         bio->bi_phys_segments++;
1342                 spin_unlock_irq(&conf->device_lock);
1343         }
1344         sectors_handled = r10_bio->sector + max_sectors -
1345                 bio->bi_iter.bi_sector;
1346
1347         atomic_set(&r10_bio->remaining, 1);
1348         bitmap_startwrite(mddev->bitmap, r10_bio->sector, r10_bio->sectors, 0);
1349
1350         for (i = 0; i < conf->copies; i++) {
1351                 struct bio *mbio;
1352                 int d = r10_bio->devs[i].devnum;
1353                 if (r10_bio->devs[i].bio) {
1354                         struct md_rdev *rdev = conf->mirrors[d].rdev;
1355                         mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1356                         bio_trim(mbio, r10_bio->sector - bio->bi_iter.bi_sector,
1357                                  max_sectors);
1358                         r10_bio->devs[i].bio = mbio;
1359
1360                         mbio->bi_iter.bi_sector = (r10_bio->devs[i].addr+
1361                                            choose_data_offset(r10_bio,
1362                                                               rdev));
1363                         mbio->bi_bdev = rdev->bdev;
1364                         mbio->bi_end_io = raid10_end_write_request;
1365                         mbio->bi_rw =
1366                                 WRITE | do_sync | do_fua | do_discard | do_same;
1367                         mbio->bi_private = r10_bio;
1368
1369                         atomic_inc(&r10_bio->remaining);
1370
1371                         cb = blk_check_plugged(raid10_unplug, mddev,
1372                                                sizeof(*plug));
1373                         if (cb)
1374                                 plug = container_of(cb, struct raid10_plug_cb,
1375                                                     cb);
1376                         else
1377                                 plug = NULL;
1378                         spin_lock_irqsave(&conf->device_lock, flags);
1379                         if (plug) {
1380                                 bio_list_add(&plug->pending, mbio);
1381                                 plug->pending_cnt++;
1382                         } else {
1383                                 bio_list_add(&conf->pending_bio_list, mbio);
1384                                 conf->pending_count++;
1385                         }
1386                         spin_unlock_irqrestore(&conf->device_lock, flags);
1387                         if (!plug)
1388                                 md_wakeup_thread(mddev->thread);
1389                 }
1390
1391                 if (r10_bio->devs[i].repl_bio) {
1392                         struct md_rdev *rdev = conf->mirrors[d].replacement;
1393                         if (rdev == NULL) {
1394                                 /* Replacement just got moved to main 'rdev' */
1395                                 smp_mb();
1396                                 rdev = conf->mirrors[d].rdev;
1397                         }
1398                         mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1399                         bio_trim(mbio, r10_bio->sector - bio->bi_iter.bi_sector,
1400                                  max_sectors);
1401                         r10_bio->devs[i].repl_bio = mbio;
1402
1403                         mbio->bi_iter.bi_sector = (r10_bio->devs[i].addr +
1404                                            choose_data_offset(
1405                                                    r10_bio, rdev));
1406                         mbio->bi_bdev = rdev->bdev;
1407                         mbio->bi_end_io = raid10_end_write_request;
1408                         mbio->bi_rw =
1409                                 WRITE | do_sync | do_fua | do_discard | do_same;
1410                         mbio->bi_private = r10_bio;
1411
1412                         atomic_inc(&r10_bio->remaining);
1413                         spin_lock_irqsave(&conf->device_lock, flags);
1414                         bio_list_add(&conf->pending_bio_list, mbio);
1415                         conf->pending_count++;
1416                         spin_unlock_irqrestore(&conf->device_lock, flags);
1417                         if (!mddev_check_plugged(mddev))
1418                                 md_wakeup_thread(mddev->thread);
1419                 }
1420         }
1421
1422         /* Don't remove the bias on 'remaining' (one_write_done) until
1423          * after checking if we need to go around again.
1424          */
1425
1426         if (sectors_handled < bio_sectors(bio)) {
1427                 one_write_done(r10_bio);
1428                 /* We need another r10_bio.  It has already been counted
1429                  * in bio->bi_phys_segments.
1430                  */
1431                 r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
1432
1433                 r10_bio->master_bio = bio;
1434                 r10_bio->sectors = bio_sectors(bio) - sectors_handled;
1435
1436                 r10_bio->mddev = mddev;
1437                 r10_bio->sector = bio->bi_iter.bi_sector + sectors_handled;
1438                 r10_bio->state = 0;
1439                 goto retry_write;
1440         }
1441         one_write_done(r10_bio);
1442 }
1443
1444 static void make_request(struct mddev *mddev, struct bio *bio)
1445 {
1446         struct r10conf *conf = mddev->private;
1447         sector_t chunk_mask = (conf->geo.chunk_mask & conf->prev.chunk_mask);
1448         int chunk_sects = chunk_mask + 1;
1449
1450         struct bio *split;
1451
1452         if (unlikely(bio->bi_rw & REQ_FLUSH)) {
1453                 md_flush_request(mddev, bio);
1454                 return;
1455         }
1456
1457         md_write_start(mddev, bio);
1458
1459         do {
1460
1461                 /*
1462                  * If this request crosses a chunk boundary, we need to split
1463                  * it.
1464                  */
1465                 if (unlikely((bio->bi_iter.bi_sector & chunk_mask) +
1466                              bio_sectors(bio) > chunk_sects
1467                              && (conf->geo.near_copies < conf->geo.raid_disks
1468                                  || conf->prev.near_copies <
1469                                  conf->prev.raid_disks))) {
1470                         split = bio_split(bio, chunk_sects -
1471                                           (bio->bi_iter.bi_sector &
1472                                            (chunk_sects - 1)),
1473                                           GFP_NOIO, fs_bio_set);
1474                         bio_chain(split, bio);
1475                 } else {
1476                         split = bio;
1477                 }
1478
1479                 __make_request(mddev, split);
1480         } while (split != bio);
1481
1482         /* In case raid10d snuck in to freeze_array */
1483         wake_up(&conf->wait_barrier);
1484 }
1485
1486 static void status(struct seq_file *seq, struct mddev *mddev)
1487 {
1488         struct r10conf *conf = mddev->private;
1489         int i;
1490
1491         if (conf->geo.near_copies < conf->geo.raid_disks)
1492                 seq_printf(seq, " %dK chunks", mddev->chunk_sectors / 2);
1493         if (conf->geo.near_copies > 1)
1494                 seq_printf(seq, " %d near-copies", conf->geo.near_copies);
1495         if (conf->geo.far_copies > 1) {
1496                 if (conf->geo.far_offset)
1497                         seq_printf(seq, " %d offset-copies", conf->geo.far_copies);
1498                 else
1499                         seq_printf(seq, " %d far-copies", conf->geo.far_copies);
1500         }
1501         seq_printf(seq, " [%d/%d] [", conf->geo.raid_disks,
1502                                         conf->geo.raid_disks - mddev->degraded);
1503         for (i = 0; i < conf->geo.raid_disks; i++)
1504                 seq_printf(seq, "%s",
1505                               conf->mirrors[i].rdev &&
1506                               test_bit(In_sync, &conf->mirrors[i].rdev->flags) ? "U" : "_");
1507         seq_printf(seq, "]");
1508 }
1509
1510 /* check if there are enough drives for
1511  * every block to appear on atleast one.
1512  * Don't consider the device numbered 'ignore'
1513  * as we might be about to remove it.
1514  */
1515 static int _enough(struct r10conf *conf, int previous, int ignore)
1516 {
1517         int first = 0;
1518         int has_enough = 0;
1519         int disks, ncopies;
1520         if (previous) {
1521                 disks = conf->prev.raid_disks;
1522                 ncopies = conf->prev.near_copies;
1523         } else {
1524                 disks = conf->geo.raid_disks;
1525                 ncopies = conf->geo.near_copies;
1526         }
1527
1528         rcu_read_lock();
1529         do {
1530                 int n = conf->copies;
1531                 int cnt = 0;
1532                 int this = first;
1533                 while (n--) {
1534                         struct md_rdev *rdev;
1535                         if (this != ignore &&
1536                             (rdev = rcu_dereference(conf->mirrors[this].rdev)) &&
1537                             test_bit(In_sync, &rdev->flags))
1538                                 cnt++;
1539                         this = (this+1) % disks;
1540                 }
1541                 if (cnt == 0)
1542                         goto out;
1543                 first = (first + ncopies) % disks;
1544         } while (first != 0);
1545         has_enough = 1;
1546 out:
1547         rcu_read_unlock();
1548         return has_enough;
1549 }
1550
1551 static int enough(struct r10conf *conf, int ignore)
1552 {
1553         /* when calling 'enough', both 'prev' and 'geo' must
1554          * be stable.
1555          * This is ensured if ->reconfig_mutex or ->device_lock
1556          * is held.
1557          */
1558         return _enough(conf, 0, ignore) &&
1559                 _enough(conf, 1, ignore);
1560 }
1561
1562 static void error(struct mddev *mddev, struct md_rdev *rdev)
1563 {
1564         char b[BDEVNAME_SIZE];
1565         struct r10conf *conf = mddev->private;
1566         unsigned long flags;
1567
1568         /*
1569          * If it is not operational, then we have already marked it as dead
1570          * else if it is the last working disks, ignore the error, let the
1571          * next level up know.
1572          * else mark the drive as failed
1573          */
1574         spin_lock_irqsave(&conf->device_lock, flags);
1575         if (test_bit(In_sync, &rdev->flags)
1576             && !enough(conf, rdev->raid_disk)) {
1577                 /*
1578                  * Don't fail the drive, just return an IO error.
1579                  */
1580                 spin_unlock_irqrestore(&conf->device_lock, flags);
1581                 return;
1582         }
1583         if (test_and_clear_bit(In_sync, &rdev->flags))
1584                 mddev->degraded++;
1585         /*
1586          * If recovery is running, make sure it aborts.
1587          */
1588         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1589         set_bit(Blocked, &rdev->flags);
1590         set_bit(Faulty, &rdev->flags);
1591         set_bit(MD_CHANGE_DEVS, &mddev->flags);
1592         spin_unlock_irqrestore(&conf->device_lock, flags);
1593         printk(KERN_ALERT
1594                "md/raid10:%s: Disk failure on %s, disabling device.\n"
1595                "md/raid10:%s: Operation continuing on %d devices.\n",
1596                mdname(mddev), bdevname(rdev->bdev, b),
1597                mdname(mddev), conf->geo.raid_disks - mddev->degraded);
1598 }
1599
1600 static void print_conf(struct r10conf *conf)
1601 {
1602         int i;
1603         struct raid10_info *tmp;
1604
1605         printk(KERN_DEBUG "RAID10 conf printout:\n");
1606         if (!conf) {
1607                 printk(KERN_DEBUG "(!conf)\n");
1608                 return;
1609         }
1610         printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->geo.raid_disks - conf->mddev->degraded,
1611                 conf->geo.raid_disks);
1612
1613         for (i = 0; i < conf->geo.raid_disks; i++) {
1614                 char b[BDEVNAME_SIZE];
1615                 tmp = conf->mirrors + i;
1616                 if (tmp->rdev)
1617                         printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
1618                                 i, !test_bit(In_sync, &tmp->rdev->flags),
1619                                 !test_bit(Faulty, &tmp->rdev->flags),
1620                                 bdevname(tmp->rdev->bdev,b));
1621         }
1622 }
1623
1624 static void close_sync(struct r10conf *conf)
1625 {
1626         wait_barrier(conf);
1627         allow_barrier(conf);
1628
1629         mempool_destroy(conf->r10buf_pool);
1630         conf->r10buf_pool = NULL;
1631 }
1632
1633 static int raid10_spare_active(struct mddev *mddev)
1634 {
1635         int i;
1636         struct r10conf *conf = mddev->private;
1637         struct raid10_info *tmp;
1638         int count = 0;
1639         unsigned long flags;
1640
1641         /*
1642          * Find all non-in_sync disks within the RAID10 configuration
1643          * and mark them in_sync
1644          */
1645         for (i = 0; i < conf->geo.raid_disks; i++) {
1646                 tmp = conf->mirrors + i;
1647                 if (tmp->replacement
1648                     && tmp->replacement->recovery_offset == MaxSector
1649                     && !test_bit(Faulty, &tmp->replacement->flags)
1650                     && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
1651                         /* Replacement has just become active */
1652                         if (!tmp->rdev
1653                             || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
1654                                 count++;
1655                         if (tmp->rdev) {
1656                                 /* Replaced device not technically faulty,
1657                                  * but we need to be sure it gets removed
1658                                  * and never re-added.
1659                                  */
1660                                 set_bit(Faulty, &tmp->rdev->flags);
1661                                 sysfs_notify_dirent_safe(
1662                                         tmp->rdev->sysfs_state);
1663                         }
1664                         sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
1665                 } else if (tmp->rdev
1666                            && tmp->rdev->recovery_offset == MaxSector
1667                            && !test_bit(Faulty, &tmp->rdev->flags)
1668                            && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
1669                         count++;
1670                         sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
1671                 }
1672         }
1673         spin_lock_irqsave(&conf->device_lock, flags);
1674         mddev->degraded -= count;
1675         spin_unlock_irqrestore(&conf->device_lock, flags);
1676
1677         print_conf(conf);
1678         return count;
1679 }
1680
1681 static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
1682 {
1683         struct r10conf *conf = mddev->private;
1684         int err = -EEXIST;
1685         int mirror;
1686         int first = 0;
1687         int last = conf->geo.raid_disks - 1;
1688
1689         if (mddev->recovery_cp < MaxSector)
1690                 /* only hot-add to in-sync arrays, as recovery is
1691                  * very different from resync
1692                  */
1693                 return -EBUSY;
1694         if (rdev->saved_raid_disk < 0 && !_enough(conf, 1, -1))
1695                 return -EINVAL;
1696
1697         if (rdev->raid_disk >= 0)
1698                 first = last = rdev->raid_disk;
1699
1700         if (rdev->saved_raid_disk >= first &&
1701             conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
1702                 mirror = rdev->saved_raid_disk;
1703         else
1704                 mirror = first;
1705         for ( ; mirror <= last ; mirror++) {
1706                 struct raid10_info *p = &conf->mirrors[mirror];
1707                 if (p->recovery_disabled == mddev->recovery_disabled)
1708                         continue;
1709                 if (p->rdev) {
1710                         if (!test_bit(WantReplacement, &p->rdev->flags) ||
1711                             p->replacement != NULL)
1712                                 continue;
1713                         clear_bit(In_sync, &rdev->flags);
1714                         set_bit(Replacement, &rdev->flags);
1715                         rdev->raid_disk = mirror;
1716                         err = 0;
1717                         if (mddev->gendisk)
1718                                 disk_stack_limits(mddev->gendisk, rdev->bdev,
1719                                                   rdev->data_offset << 9);
1720                         conf->fullsync = 1;
1721                         rcu_assign_pointer(p->replacement, rdev);
1722                         break;
1723                 }
1724
1725                 if (mddev->gendisk)
1726                         disk_stack_limits(mddev->gendisk, rdev->bdev,
1727                                           rdev->data_offset << 9);
1728
1729                 p->head_position = 0;
1730                 p->recovery_disabled = mddev->recovery_disabled - 1;
1731                 rdev->raid_disk = mirror;
1732                 err = 0;
1733                 if (rdev->saved_raid_disk != mirror)
1734                         conf->fullsync = 1;
1735                 rcu_assign_pointer(p->rdev, rdev);
1736                 break;
1737         }
1738         md_integrity_add_rdev(rdev, mddev);
1739         if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
1740                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
1741
1742         print_conf(conf);
1743         return err;
1744 }
1745
1746 static int raid10_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
1747 {
1748         struct r10conf *conf = mddev->private;
1749         int err = 0;
1750         int number = rdev->raid_disk;
1751         struct md_rdev **rdevp;
1752         struct raid10_info *p = conf->mirrors + number;
1753
1754         print_conf(conf);
1755         if (rdev == p->rdev)
1756                 rdevp = &p->rdev;
1757         else if (rdev == p->replacement)
1758                 rdevp = &p->replacement;
1759         else
1760                 return 0;
1761
1762         if (test_bit(In_sync, &rdev->flags) ||
1763             atomic_read(&rdev->nr_pending)) {
1764                 err = -EBUSY;
1765                 goto abort;
1766         }
1767         /* Only remove faulty devices if recovery
1768          * is not possible.
1769          */
1770         if (!test_bit(Faulty, &rdev->flags) &&
1771             mddev->recovery_disabled != p->recovery_disabled &&
1772             (!p->replacement || p->replacement == rdev) &&
1773             number < conf->geo.raid_disks &&
1774             enough(conf, -1)) {
1775                 err = -EBUSY;
1776                 goto abort;
1777         }
1778         *rdevp = NULL;
1779         synchronize_rcu();
1780         if (atomic_read(&rdev->nr_pending)) {
1781                 /* lost the race, try later */
1782                 err = -EBUSY;
1783                 *rdevp = rdev;
1784                 goto abort;
1785         } else if (p->replacement) {
1786                 /* We must have just cleared 'rdev' */
1787                 p->rdev = p->replacement;
1788                 clear_bit(Replacement, &p->replacement->flags);
1789                 smp_mb(); /* Make sure other CPUs may see both as identical
1790                            * but will never see neither -- if they are careful.
1791                            */
1792                 p->replacement = NULL;
1793                 clear_bit(WantReplacement, &rdev->flags);
1794         } else
1795                 /* We might have just remove the Replacement as faulty
1796                  * Clear the flag just in case
1797                  */
1798                 clear_bit(WantReplacement, &rdev->flags);
1799
1800         err = md_integrity_register(mddev);
1801
1802 abort:
1803
1804         print_conf(conf);
1805         return err;
1806 }
1807
1808 static void end_sync_read(struct bio *bio)
1809 {
1810         struct r10bio *r10_bio = bio->bi_private;
1811         struct r10conf *conf = r10_bio->mddev->private;
1812         int d;
1813
1814         if (bio == r10_bio->master_bio) {
1815                 /* this is a reshape read */
1816                 d = r10_bio->read_slot; /* really the read dev */
1817         } else
1818                 d = find_bio_disk(conf, r10_bio, bio, NULL, NULL);
1819
1820         if (!bio->bi_error)
1821                 set_bit(R10BIO_Uptodate, &r10_bio->state);
1822         else
1823                 /* The write handler will notice the lack of
1824                  * R10BIO_Uptodate and record any errors etc
1825                  */
1826                 atomic_add(r10_bio->sectors,
1827                            &conf->mirrors[d].rdev->corrected_errors);
1828
1829         /* for reconstruct, we always reschedule after a read.
1830          * for resync, only after all reads
1831          */
1832         rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev);
1833         if (test_bit(R10BIO_IsRecover, &r10_bio->state) ||
1834             atomic_dec_and_test(&r10_bio->remaining)) {
1835                 /* we have read all the blocks,
1836                  * do the comparison in process context in raid10d
1837                  */
1838                 reschedule_retry(r10_bio);
1839         }
1840 }
1841
1842 static void end_sync_request(struct r10bio *r10_bio)
1843 {
1844         struct mddev *mddev = r10_bio->mddev;
1845
1846         while (atomic_dec_and_test(&r10_bio->remaining)) {
1847                 if (r10_bio->master_bio == NULL) {
1848                         /* the primary of several recovery bios */
1849                         sector_t s = r10_bio->sectors;
1850                         if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
1851                             test_bit(R10BIO_WriteError, &r10_bio->state))
1852                                 reschedule_retry(r10_bio);
1853                         else
1854                                 put_buf(r10_bio);
1855                         md_done_sync(mddev, s, 1);
1856                         break;
1857                 } else {
1858                         struct r10bio *r10_bio2 = (struct r10bio *)r10_bio->master_bio;
1859                         if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
1860                             test_bit(R10BIO_WriteError, &r10_bio->state))
1861                                 reschedule_retry(r10_bio);
1862                         else
1863                                 put_buf(r10_bio);
1864                         r10_bio = r10_bio2;
1865                 }
1866         }
1867 }
1868
1869 static void end_sync_write(struct bio *bio)
1870 {
1871         struct r10bio *r10_bio = bio->bi_private;
1872         struct mddev *mddev = r10_bio->mddev;
1873         struct r10conf *conf = mddev->private;
1874         int d;
1875         sector_t first_bad;
1876         int bad_sectors;
1877         int slot;
1878         int repl;
1879         struct md_rdev *rdev = NULL;
1880
1881         d = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
1882         if (repl)
1883                 rdev = conf->mirrors[d].replacement;
1884         else
1885                 rdev = conf->mirrors[d].rdev;
1886
1887         if (bio->bi_error) {
1888                 if (repl)
1889                         md_error(mddev, rdev);
1890                 else {
1891                         set_bit(WriteErrorSeen, &rdev->flags);
1892                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
1893                                 set_bit(MD_RECOVERY_NEEDED,
1894                                         &rdev->mddev->recovery);
1895                         set_bit(R10BIO_WriteError, &r10_bio->state);
1896                 }
1897         } else if (is_badblock(rdev,
1898                              r10_bio->devs[slot].addr,
1899                              r10_bio->sectors,
1900                              &first_bad, &bad_sectors))
1901                 set_bit(R10BIO_MadeGood, &r10_bio->state);
1902
1903         rdev_dec_pending(rdev, mddev);
1904
1905         end_sync_request(r10_bio);
1906 }
1907
1908 /*
1909  * Note: sync and recover and handled very differently for raid10
1910  * This code is for resync.
1911  * For resync, we read through virtual addresses and read all blocks.
1912  * If there is any error, we schedule a write.  The lowest numbered
1913  * drive is authoritative.
1914  * However requests come for physical address, so we need to map.
1915  * For every physical address there are raid_disks/copies virtual addresses,
1916  * which is always are least one, but is not necessarly an integer.
1917  * This means that a physical address can span multiple chunks, so we may
1918  * have to submit multiple io requests for a single sync request.
1919  */
1920 /*
1921  * We check if all blocks are in-sync and only write to blocks that
1922  * aren't in sync
1923  */
1924 static void sync_request_write(struct mddev *mddev, struct r10bio *r10_bio)
1925 {
1926         struct r10conf *conf = mddev->private;
1927         int i, first;
1928         struct bio *tbio, *fbio;
1929         int vcnt;
1930
1931         atomic_set(&r10_bio->remaining, 1);
1932
1933         /* find the first device with a block */
1934         for (i=0; i<conf->copies; i++)
1935                 if (!r10_bio->devs[i].bio->bi_error)
1936                         break;
1937
1938         if (i == conf->copies)
1939                 goto done;
1940
1941         first = i;
1942         fbio = r10_bio->devs[i].bio;
1943
1944         vcnt = (r10_bio->sectors + (PAGE_SIZE >> 9) - 1) >> (PAGE_SHIFT - 9);
1945         /* now find blocks with errors */
1946         for (i=0 ; i < conf->copies ; i++) {
1947                 int  j, d;
1948
1949                 tbio = r10_bio->devs[i].bio;
1950
1951                 if (tbio->bi_end_io != end_sync_read)
1952                         continue;
1953                 if (i == first)
1954                         continue;
1955                 if (!r10_bio->devs[i].bio->bi_error) {
1956                         /* We know that the bi_io_vec layout is the same for
1957                          * both 'first' and 'i', so we just compare them.
1958                          * All vec entries are PAGE_SIZE;
1959                          */
1960                         int sectors = r10_bio->sectors;
1961                         for (j = 0; j < vcnt; j++) {
1962                                 int len = PAGE_SIZE;
1963                                 if (sectors < (len / 512))
1964                                         len = sectors * 512;
1965                                 if (memcmp(page_address(fbio->bi_io_vec[j].bv_page),
1966                                            page_address(tbio->bi_io_vec[j].bv_page),
1967                                            len))
1968                                         break;
1969                                 sectors -= len/512;
1970                         }
1971                         if (j == vcnt)
1972                                 continue;
1973                         atomic64_add(r10_bio->sectors, &mddev->resync_mismatches);
1974                         if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
1975                                 /* Don't fix anything. */
1976                                 continue;
1977                 }
1978                 /* Ok, we need to write this bio, either to correct an
1979                  * inconsistency or to correct an unreadable block.
1980                  * First we need to fixup bv_offset, bv_len and
1981                  * bi_vecs, as the read request might have corrupted these
1982                  */
1983                 bio_reset(tbio);
1984
1985                 tbio->bi_vcnt = vcnt;
1986                 tbio->bi_iter.bi_size = r10_bio->sectors << 9;
1987                 tbio->bi_rw = WRITE;
1988                 tbio->bi_private = r10_bio;
1989                 tbio->bi_iter.bi_sector = r10_bio->devs[i].addr;
1990                 tbio->bi_end_io = end_sync_write;
1991
1992                 bio_copy_data(tbio, fbio);
1993
1994                 d = r10_bio->devs[i].devnum;
1995                 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
1996                 atomic_inc(&r10_bio->remaining);
1997                 md_sync_acct(conf->mirrors[d].rdev->bdev, bio_sectors(tbio));
1998
1999                 tbio->bi_iter.bi_sector += conf->mirrors[d].rdev->data_offset;
2000                 tbio->bi_bdev = conf->mirrors[d].rdev->bdev;
2001                 generic_make_request(tbio);
2002         }
2003
2004         /* Now write out to any replacement devices
2005          * that are active
2006          */
2007         for (i = 0; i < conf->copies; i++) {
2008                 int d;
2009
2010                 tbio = r10_bio->devs[i].repl_bio;
2011                 if (!tbio || !tbio->bi_end_io)
2012                         continue;
2013                 if (r10_bio->devs[i].bio->bi_end_io != end_sync_write
2014                     && r10_bio->devs[i].bio != fbio)
2015                         bio_copy_data(tbio, fbio);
2016                 d = r10_bio->devs[i].devnum;
2017                 atomic_inc(&r10_bio->remaining);
2018                 md_sync_acct(conf->mirrors[d].replacement->bdev,
2019                              bio_sectors(tbio));
2020                 generic_make_request(tbio);
2021         }
2022
2023 done:
2024         if (atomic_dec_and_test(&r10_bio->remaining)) {
2025                 md_done_sync(mddev, r10_bio->sectors, 1);
2026                 put_buf(r10_bio);
2027         }
2028 }
2029
2030 /*
2031  * Now for the recovery code.
2032  * Recovery happens across physical sectors.
2033  * We recover all non-is_sync drives by finding the virtual address of
2034  * each, and then choose a working drive that also has that virt address.
2035  * There is a separate r10_bio for each non-in_sync drive.
2036  * Only the first two slots are in use. The first for reading,
2037  * The second for writing.
2038  *
2039  */
2040 static void fix_recovery_read_error(struct r10bio *r10_bio)
2041 {
2042         /* We got a read error during recovery.
2043          * We repeat the read in smaller page-sized sections.
2044          * If a read succeeds, write it to the new device or record
2045          * a bad block if we cannot.
2046          * If a read fails, record a bad block on both old and
2047          * new devices.
2048          */
2049         struct mddev *mddev = r10_bio->mddev;
2050         struct r10conf *conf = mddev->private;
2051         struct bio *bio = r10_bio->devs[0].bio;
2052         sector_t sect = 0;
2053         int sectors = r10_bio->sectors;
2054         int idx = 0;
2055         int dr = r10_bio->devs[0].devnum;
2056         int dw = r10_bio->devs[1].devnum;
2057
2058         while (sectors) {
2059                 int s = sectors;
2060                 struct md_rdev *rdev;
2061                 sector_t addr;
2062                 int ok;
2063
2064                 if (s > (PAGE_SIZE>>9))
2065                         s = PAGE_SIZE >> 9;
2066
2067                 rdev = conf->mirrors[dr].rdev;
2068                 addr = r10_bio->devs[0].addr + sect,
2069                 ok = sync_page_io(rdev,
2070                                   addr,
2071                                   s << 9,
2072                                   bio->bi_io_vec[idx].bv_page,
2073                                   READ, false);
2074                 if (ok) {
2075                         rdev = conf->mirrors[dw].rdev;
2076                         addr = r10_bio->devs[1].addr + sect;
2077                         ok = sync_page_io(rdev,
2078                                           addr,
2079                                           s << 9,
2080                                           bio->bi_io_vec[idx].bv_page,
2081                                           WRITE, false);
2082                         if (!ok) {
2083                                 set_bit(WriteErrorSeen, &rdev->flags);
2084                                 if (!test_and_set_bit(WantReplacement,
2085                                                       &rdev->flags))
2086                                         set_bit(MD_RECOVERY_NEEDED,
2087                                                 &rdev->mddev->recovery);
2088                         }
2089                 }
2090                 if (!ok) {
2091                         /* We don't worry if we cannot set a bad block -
2092                          * it really is bad so there is no loss in not
2093                          * recording it yet
2094                          */
2095                         rdev_set_badblocks(rdev, addr, s, 0);
2096
2097                         if (rdev != conf->mirrors[dw].rdev) {
2098                                 /* need bad block on destination too */
2099                                 struct md_rdev *rdev2 = conf->mirrors[dw].rdev;
2100                                 addr = r10_bio->devs[1].addr + sect;
2101                                 ok = rdev_set_badblocks(rdev2, addr, s, 0);
2102                                 if (!ok) {
2103                                         /* just abort the recovery */
2104                                         printk(KERN_NOTICE
2105                                                "md/raid10:%s: recovery aborted"
2106                                                " due to read error\n",
2107                                                mdname(mddev));
2108
2109                                         conf->mirrors[dw].recovery_disabled
2110                                                 = mddev->recovery_disabled;
2111                                         set_bit(MD_RECOVERY_INTR,
2112                                                 &mddev->recovery);
2113                                         break;
2114                                 }
2115                         }
2116                 }
2117
2118                 sectors -= s;
2119                 sect += s;
2120                 idx++;
2121         }
2122 }
2123
2124 static void recovery_request_write(struct mddev *mddev, struct r10bio *r10_bio)
2125 {
2126         struct r10conf *conf = mddev->private;
2127         int d;
2128         struct bio *wbio, *wbio2;
2129
2130         if (!test_bit(R10BIO_Uptodate, &r10_bio->state)) {
2131                 fix_recovery_read_error(r10_bio);
2132                 end_sync_request(r10_bio);
2133                 return;
2134         }
2135
2136         /*
2137          * share the pages with the first bio
2138          * and submit the write request
2139          */
2140         d = r10_bio->devs[1].devnum;
2141         wbio = r10_bio->devs[1].bio;
2142         wbio2 = r10_bio->devs[1].repl_bio;
2143         /* Need to test wbio2->bi_end_io before we call
2144          * generic_make_request as if the former is NULL,
2145          * the latter is free to free wbio2.
2146          */
2147         if (wbio2 && !wbio2->bi_end_io)
2148                 wbio2 = NULL;
2149         if (wbio->bi_end_io) {
2150                 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
2151                 md_sync_acct(conf->mirrors[d].rdev->bdev, bio_sectors(wbio));
2152                 generic_make_request(wbio);
2153         }
2154         if (wbio2) {
2155                 atomic_inc(&conf->mirrors[d].replacement->nr_pending);
2156                 md_sync_acct(conf->mirrors[d].replacement->bdev,
2157                              bio_sectors(wbio2));
2158                 generic_make_request(wbio2);
2159         }
2160 }
2161
2162 /*
2163  * Used by fix_read_error() to decay the per rdev read_errors.
2164  * We halve the read error count for every hour that has elapsed
2165  * since the last recorded read error.
2166  *
2167  */
2168 static void check_decay_read_errors(struct mddev *mddev, struct md_rdev *rdev)
2169 {
2170         struct timespec cur_time_mon;
2171         unsigned long hours_since_last;
2172         unsigned int read_errors = atomic_read(&rdev->read_errors);
2173
2174         ktime_get_ts(&cur_time_mon);
2175
2176         if (rdev->last_read_error.tv_sec == 0 &&
2177             rdev->last_read_error.tv_nsec == 0) {
2178                 /* first time we've seen a read error */
2179                 rdev->last_read_error = cur_time_mon;
2180                 return;
2181         }
2182
2183         hours_since_last = (cur_time_mon.tv_sec -
2184                             rdev->last_read_error.tv_sec) / 3600;
2185
2186         rdev->last_read_error = cur_time_mon;
2187
2188         /*
2189          * if hours_since_last is > the number of bits in read_errors
2190          * just set read errors to 0. We do this to avoid
2191          * overflowing the shift of read_errors by hours_since_last.
2192          */
2193         if (hours_since_last >= 8 * sizeof(read_errors))
2194                 atomic_set(&rdev->read_errors, 0);
2195         else
2196                 atomic_set(&rdev->read_errors, read_errors >> hours_since_last);
2197 }
2198
2199 static int r10_sync_page_io(struct md_rdev *rdev, sector_t sector,
2200                             int sectors, struct page *page, int rw)
2201 {
2202         sector_t first_bad;
2203         int bad_sectors;
2204
2205         if (is_badblock(rdev, sector, sectors, &first_bad, &bad_sectors)
2206             && (rw == READ || test_bit(WriteErrorSeen, &rdev->flags)))
2207                 return -1;
2208         if (sync_page_io(rdev, sector, sectors << 9, page, rw, false))
2209                 /* success */
2210                 return 1;
2211         if (rw == WRITE) {
2212                 set_bit(WriteErrorSeen, &rdev->flags);
2213                 if (!test_and_set_bit(WantReplacement, &rdev->flags))
2214                         set_bit(MD_RECOVERY_NEEDED,
2215                                 &rdev->mddev->recovery);
2216         }
2217         /* need to record an error - either for the block or the device */
2218         if (!rdev_set_badblocks(rdev, sector, sectors, 0))
2219                 md_error(rdev->mddev, rdev);
2220         return 0;
2221 }
2222
2223 /*
2224  * This is a kernel thread which:
2225  *
2226  *      1.      Retries failed read operations on working mirrors.
2227  *      2.      Updates the raid superblock when problems encounter.
2228  *      3.      Performs writes following reads for array synchronising.
2229  */
2230
2231 static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10bio *r10_bio)
2232 {
2233         int sect = 0; /* Offset from r10_bio->sector */
2234         int sectors = r10_bio->sectors;
2235         struct md_rdev*rdev;
2236         int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
2237         int d = r10_bio->devs[r10_bio->read_slot].devnum;
2238
2239         /* still own a reference to this rdev, so it cannot
2240          * have been cleared recently.
2241          */
2242         rdev = conf->mirrors[d].rdev;
2243
2244         if (test_bit(Faulty, &rdev->flags))
2245                 /* drive has already been failed, just ignore any
2246                    more fix_read_error() attempts */
2247                 return;
2248
2249         check_decay_read_errors(mddev, rdev);
2250         atomic_inc(&rdev->read_errors);
2251         if (atomic_read(&rdev->read_errors) > max_read_errors) {
2252                 char b[BDEVNAME_SIZE];
2253                 bdevname(rdev->bdev, b);
2254
2255                 printk(KERN_NOTICE
2256                        "md/raid10:%s: %s: Raid device exceeded "
2257                        "read_error threshold [cur %d:max %d]\n",
2258                        mdname(mddev), b,
2259                        atomic_read(&rdev->read_errors), max_read_errors);
2260                 printk(KERN_NOTICE
2261                        "md/raid10:%s: %s: Failing raid device\n",
2262                        mdname(mddev), b);
2263                 md_error(mddev, conf->mirrors[d].rdev);
2264                 r10_bio->devs[r10_bio->read_slot].bio = IO_BLOCKED;
2265                 return;
2266         }
2267
2268         while(sectors) {
2269                 int s = sectors;
2270                 int sl = r10_bio->read_slot;
2271                 int success = 0;
2272                 int start;
2273
2274                 if (s > (PAGE_SIZE>>9))
2275                         s = PAGE_SIZE >> 9;
2276
2277                 rcu_read_lock();
2278                 do {
2279                         sector_t first_bad;
2280                         int bad_sectors;
2281
2282                         d = r10_bio->devs[sl].devnum;
2283                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2284                         if (rdev &&
2285                             test_bit(In_sync, &rdev->flags) &&
2286                             is_badblock(rdev, r10_bio->devs[sl].addr + sect, s,
2287                                         &first_bad, &bad_sectors) == 0) {
2288                                 atomic_inc(&rdev->nr_pending);
2289                                 rcu_read_unlock();
2290                                 success = sync_page_io(rdev,
2291                                                        r10_bio->devs[sl].addr +
2292                                                        sect,
2293                                                        s<<9,
2294                                                        conf->tmppage, READ, false);
2295                                 rdev_dec_pending(rdev, mddev);
2296                                 rcu_read_lock();
2297                                 if (success)
2298                                         break;
2299                         }
2300                         sl++;
2301                         if (sl == conf->copies)
2302                                 sl = 0;
2303                 } while (!success && sl != r10_bio->read_slot);
2304                 rcu_read_unlock();
2305
2306                 if (!success) {
2307                         /* Cannot read from anywhere, just mark the block
2308                          * as bad on the first device to discourage future
2309                          * reads.
2310                          */
2311                         int dn = r10_bio->devs[r10_bio->read_slot].devnum;
2312                         rdev = conf->mirrors[dn].rdev;
2313
2314                         if (!rdev_set_badblocks(
2315                                     rdev,
2316                                     r10_bio->devs[r10_bio->read_slot].addr
2317                                     + sect,
2318                                     s, 0)) {
2319                                 md_error(mddev, rdev);
2320                                 r10_bio->devs[r10_bio->read_slot].bio
2321                                         = IO_BLOCKED;
2322                         }
2323                         break;
2324                 }
2325
2326                 start = sl;
2327                 /* write it back and re-read */
2328                 rcu_read_lock();
2329                 while (sl != r10_bio->read_slot) {
2330                         char b[BDEVNAME_SIZE];
2331
2332                         if (sl==0)
2333                                 sl = conf->copies;
2334                         sl--;
2335                         d = r10_bio->devs[sl].devnum;
2336                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2337                         if (!rdev ||
2338                             !test_bit(In_sync, &rdev->flags))
2339                                 continue;
2340
2341                         atomic_inc(&rdev->nr_pending);
2342                         rcu_read_unlock();
2343                         if (r10_sync_page_io(rdev,
2344                                              r10_bio->devs[sl].addr +
2345                                              sect,
2346                                              s, conf->tmppage, WRITE)
2347                             == 0) {
2348                                 /* Well, this device is dead */
2349                                 printk(KERN_NOTICE
2350                                        "md/raid10:%s: read correction "
2351                                        "write failed"
2352                                        " (%d sectors at %llu on %s)\n",
2353                                        mdname(mddev), s,
2354                                        (unsigned long long)(
2355                                                sect +
2356                                                choose_data_offset(r10_bio,
2357                                                                   rdev)),
2358                                        bdevname(rdev->bdev, b));
2359                                 printk(KERN_NOTICE "md/raid10:%s: %s: failing "
2360                                        "drive\n",
2361                                        mdname(mddev),
2362                                        bdevname(rdev->bdev, b));
2363                         }
2364                         rdev_dec_pending(rdev, mddev);
2365                         rcu_read_lock();
2366                 }
2367                 sl = start;
2368                 while (sl != r10_bio->read_slot) {
2369                         char b[BDEVNAME_SIZE];
2370
2371                         if (sl==0)
2372                                 sl = conf->copies;
2373                         sl--;
2374                         d = r10_bio->devs[sl].devnum;
2375                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2376                         if (!rdev ||
2377                             !test_bit(In_sync, &rdev->flags))
2378                                 continue;
2379
2380                         atomic_inc(&rdev->nr_pending);
2381                         rcu_read_unlock();
2382                         switch (r10_sync_page_io(rdev,
2383                                              r10_bio->devs[sl].addr +
2384                                              sect,
2385                                              s, conf->tmppage,
2386                                                  READ)) {
2387                         case 0:
2388                                 /* Well, this device is dead */
2389                                 printk(KERN_NOTICE
2390                                        "md/raid10:%s: unable to read back "
2391                                        "corrected sectors"
2392                                        " (%d sectors at %llu on %s)\n",
2393                                        mdname(mddev), s,
2394                                        (unsigned long long)(
2395                                                sect +
2396                                                choose_data_offset(r10_bio, rdev)),
2397                                        bdevname(rdev->bdev, b));
2398                                 printk(KERN_NOTICE "md/raid10:%s: %s: failing "
2399                                        "drive\n",
2400                                        mdname(mddev),
2401                                        bdevname(rdev->bdev, b));
2402                                 break;
2403                         case 1:
2404                                 printk(KERN_INFO
2405                                        "md/raid10:%s: read error corrected"
2406                                        " (%d sectors at %llu on %s)\n",
2407                                        mdname(mddev), s,
2408                                        (unsigned long long)(
2409                                                sect +
2410                                                choose_data_offset(r10_bio, rdev)),
2411                                        bdevname(rdev->bdev, b));
2412                                 atomic_add(s, &rdev->corrected_errors);
2413                         }
2414
2415                         rdev_dec_pending(rdev, mddev);
2416                         rcu_read_lock();
2417                 }
2418                 rcu_read_unlock();
2419
2420                 sectors -= s;
2421                 sect += s;
2422         }
2423 }
2424
2425 static int narrow_write_error(struct r10bio *r10_bio, int i)
2426 {
2427         struct bio *bio = r10_bio->master_bio;
2428         struct mddev *mddev = r10_bio->mddev;
2429         struct r10conf *conf = mddev->private;
2430         struct md_rdev *rdev = conf->mirrors[r10_bio->devs[i].devnum].rdev;
2431         /* bio has the data to be written to slot 'i' where
2432          * we just recently had a write error.
2433          * We repeatedly clone the bio and trim down to one block,
2434          * then try the write.  Where the write fails we record
2435          * a bad block.
2436          * It is conceivable that the bio doesn't exactly align with
2437          * blocks.  We must handle this.
2438          *
2439          * We currently own a reference to the rdev.
2440          */
2441
2442         int block_sectors;
2443         sector_t sector;
2444         int sectors;
2445         int sect_to_write = r10_bio->sectors;
2446         int ok = 1;
2447
2448         if (rdev->badblocks.shift < 0)
2449                 return 0;
2450
2451         block_sectors = roundup(1 << rdev->badblocks.shift,
2452                                 bdev_logical_block_size(rdev->bdev) >> 9);
2453         sector = r10_bio->sector;
2454         sectors = ((r10_bio->sector + block_sectors)
2455                    & ~(sector_t)(block_sectors - 1))
2456                 - sector;
2457
2458         while (sect_to_write) {
2459                 struct bio *wbio;
2460                 if (sectors > sect_to_write)
2461                         sectors = sect_to_write;
2462                 /* Write at 'sector' for 'sectors' */
2463                 wbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
2464                 bio_trim(wbio, sector - bio->bi_iter.bi_sector, sectors);
2465                 wbio->bi_iter.bi_sector = (r10_bio->devs[i].addr+
2466                                    choose_data_offset(r10_bio, rdev) +
2467                                    (sector - r10_bio->sector));
2468                 wbio->bi_bdev = rdev->bdev;
2469                 if (submit_bio_wait(WRITE, wbio) == 0)
2470                         /* Failure! */
2471                         ok = rdev_set_badblocks(rdev, sector,
2472                                                 sectors, 0)
2473                                 && ok;
2474
2475                 bio_put(wbio);
2476                 sect_to_write -= sectors;
2477                 sector += sectors;
2478                 sectors = block_sectors;
2479         }
2480         return ok;
2481 }
2482
2483 static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)
2484 {
2485         int slot = r10_bio->read_slot;
2486         struct bio *bio;
2487         struct r10conf *conf = mddev->private;
2488         struct md_rdev *rdev = r10_bio->devs[slot].rdev;
2489         char b[BDEVNAME_SIZE];
2490         unsigned long do_sync;
2491         int max_sectors;
2492
2493         /* we got a read error. Maybe the drive is bad.  Maybe just
2494          * the block and we can fix it.
2495          * We freeze all other IO, and try reading the block from
2496          * other devices.  When we find one, we re-write
2497          * and check it that fixes the read error.
2498          * This is all done synchronously while the array is
2499          * frozen.
2500          */
2501         bio = r10_bio->devs[slot].bio;
2502         bdevname(bio->bi_bdev, b);
2503         bio_put(bio);
2504         r10_bio->devs[slot].bio = NULL;
2505
2506         if (mddev->ro == 0) {
2507                 freeze_array(conf, 1);
2508                 fix_read_error(conf, mddev, r10_bio);
2509                 unfreeze_array(conf);
2510         } else
2511                 r10_bio->devs[slot].bio = IO_BLOCKED;
2512
2513         rdev_dec_pending(rdev, mddev);
2514
2515 read_more:
2516         rdev = read_balance(conf, r10_bio, &max_sectors);
2517         if (rdev == NULL) {
2518                 printk(KERN_ALERT "md/raid10:%s: %s: unrecoverable I/O"
2519                        " read error for block %llu\n",
2520                        mdname(mddev), b,
2521                        (unsigned long long)r10_bio->sector);
2522                 raid_end_bio_io(r10_bio);
2523                 return;
2524         }
2525
2526         do_sync = (r10_bio->master_bio->bi_rw & REQ_SYNC);
2527         slot = r10_bio->read_slot;
2528         printk_ratelimited(
2529                 KERN_ERR
2530                 "md/raid10:%s: %s: redirecting "
2531                 "sector %llu to another mirror\n",
2532                 mdname(mddev),
2533                 bdevname(rdev->bdev, b),
2534                 (unsigned long long)r10_bio->sector);
2535         bio = bio_clone_mddev(r10_bio->master_bio,
2536                               GFP_NOIO, mddev);
2537         bio_trim(bio, r10_bio->sector - bio->bi_iter.bi_sector, max_sectors);
2538         r10_bio->devs[slot].bio = bio;
2539         r10_bio->devs[slot].rdev = rdev;
2540         bio->bi_iter.bi_sector = r10_bio->devs[slot].addr
2541                 + choose_data_offset(r10_bio, rdev);
2542         bio->bi_bdev = rdev->bdev;
2543         bio->bi_rw = READ | do_sync;
2544         bio->bi_private = r10_bio;
2545         bio->bi_end_io = raid10_end_read_request;
2546         if (max_sectors < r10_bio->sectors) {
2547                 /* Drat - have to split this up more */
2548                 struct bio *mbio = r10_bio->master_bio;
2549                 int sectors_handled =
2550                         r10_bio->sector + max_sectors
2551                         - mbio->bi_iter.bi_sector;
2552                 r10_bio->sectors = max_sectors;
2553                 spin_lock_irq(&conf->device_lock);
2554                 if (mbio->bi_phys_segments == 0)
2555                         mbio->bi_phys_segments = 2;
2556                 else
2557                         mbio->bi_phys_segments++;
2558                 spin_unlock_irq(&conf->device_lock);
2559                 generic_make_request(bio);
2560
2561                 r10_bio = mempool_alloc(conf->r10bio_pool,
2562                                         GFP_NOIO);
2563                 r10_bio->master_bio = mbio;
2564                 r10_bio->sectors = bio_sectors(mbio) - sectors_handled;
2565                 r10_bio->state = 0;
2566                 set_bit(R10BIO_ReadError,
2567                         &r10_bio->state);
2568                 r10_bio->mddev = mddev;
2569                 r10_bio->sector = mbio->bi_iter.bi_sector
2570                         + sectors_handled;
2571
2572                 goto read_more;
2573         } else
2574                 generic_make_request(bio);
2575 }
2576
2577 static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)
2578 {
2579         /* Some sort of write request has finished and it
2580          * succeeded in writing where we thought there was a
2581          * bad block.  So forget the bad block.
2582          * Or possibly if failed and we need to record
2583          * a bad block.
2584          */
2585         int m;
2586         struct md_rdev *rdev;
2587
2588         if (test_bit(R10BIO_IsSync, &r10_bio->state) ||
2589             test_bit(R10BIO_IsRecover, &r10_bio->state)) {
2590                 for (m = 0; m < conf->copies; m++) {
2591                         int dev = r10_bio->devs[m].devnum;
2592                         rdev = conf->mirrors[dev].rdev;
2593                         if (r10_bio->devs[m].bio == NULL)
2594                                 continue;
2595                         if (!r10_bio->devs[m].bio->bi_error) {
2596                                 rdev_clear_badblocks(
2597                                         rdev,
2598                                         r10_bio->devs[m].addr,
2599                                         r10_bio->sectors, 0);
2600                         } else {
2601                                 if (!rdev_set_badblocks(
2602                                             rdev,
2603                                             r10_bio->devs[m].addr,
2604                                             r10_bio->sectors, 0))
2605                                         md_error(conf->mddev, rdev);
2606                         }
2607                         rdev = conf->mirrors[dev].replacement;
2608                         if (r10_bio->devs[m].repl_bio == NULL)
2609                                 continue;
2610
2611                         if (!r10_bio->devs[m].repl_bio->bi_error) {
2612                                 rdev_clear_badblocks(
2613                                         rdev,
2614                                         r10_bio->devs[m].addr,
2615                                         r10_bio->sectors, 0);
2616                         } else {
2617                                 if (!rdev_set_badblocks(
2618                                             rdev,
2619                                             r10_bio->devs[m].addr,
2620                                             r10_bio->sectors, 0))
2621                                         md_error(conf->mddev, rdev);
2622                         }
2623                 }
2624                 put_buf(r10_bio);
2625         } else {
2626                 for (m = 0; m < conf->copies; m++) {
2627                         int dev = r10_bio->devs[m].devnum;
2628                         struct bio *bio = r10_bio->devs[m].bio;
2629                         rdev = conf->mirrors[dev].rdev;
2630                         if (bio == IO_MADE_GOOD) {
2631                                 rdev_clear_badblocks(
2632                                         rdev,
2633                                         r10_bio->devs[m].addr,
2634                                         r10_bio->sectors, 0);
2635                                 rdev_dec_pending(rdev, conf->mddev);
2636                         } else if (bio != NULL && bio->bi_error) {
2637                                 if (!narrow_write_error(r10_bio, m)) {
2638                                         md_error(conf->mddev, rdev);
2639                                         set_bit(R10BIO_Degraded,
2640                                                 &r10_bio->state);
2641                                 }
2642                                 rdev_dec_pending(rdev, conf->mddev);
2643                         }
2644                         bio = r10_bio->devs[m].repl_bio;
2645                         rdev = conf->mirrors[dev].replacement;
2646                         if (rdev && bio == IO_MADE_GOOD) {
2647                                 rdev_clear_badblocks(
2648                                         rdev,
2649                                         r10_bio->devs[m].addr,
2650                                         r10_bio->sectors, 0);
2651                                 rdev_dec_pending(rdev, conf->mddev);
2652                         }
2653                 }
2654                 if (test_bit(R10BIO_WriteError,
2655                              &r10_bio->state))
2656                         close_write(r10_bio);
2657                 raid_end_bio_io(r10_bio);
2658         }
2659 }
2660
2661 static void raid10d(struct md_thread *thread)
2662 {
2663         struct mddev *mddev = thread->mddev;
2664         struct r10bio *r10_bio;
2665         unsigned long flags;
2666         struct r10conf *conf = mddev->private;
2667         struct list_head *head = &conf->retry_list;
2668         struct blk_plug plug;
2669
2670         md_check_recovery(mddev);
2671
2672         blk_start_plug(&plug);
2673         for (;;) {
2674
2675                 flush_pending_writes(conf);
2676
2677                 spin_lock_irqsave(&conf->device_lock, flags);
2678                 if (list_empty(head)) {
2679                         spin_unlock_irqrestore(&conf->device_lock, flags);
2680                         break;
2681                 }
2682                 r10_bio = list_entry(head->prev, struct r10bio, retry_list);
2683                 list_del(head->prev);
2684                 conf->nr_queued--;
2685                 spin_unlock_irqrestore(&conf->device_lock, flags);
2686
2687                 mddev = r10_bio->mddev;
2688                 conf = mddev->private;
2689                 if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
2690                     test_bit(R10BIO_WriteError, &r10_bio->state))
2691                         handle_write_completed(conf, r10_bio);
2692                 else if (test_bit(R10BIO_IsReshape, &r10_bio->state))
2693                         reshape_request_write(mddev, r10_bio);
2694                 else if (test_bit(R10BIO_IsSync, &r10_bio->state))
2695                         sync_request_write(mddev, r10_bio);
2696                 else if (test_bit(R10BIO_IsRecover, &r10_bio->state))
2697                         recovery_request_write(mddev, r10_bio);
2698                 else if (test_bit(R10BIO_ReadError, &r10_bio->state))
2699                         handle_read_error(mddev, r10_bio);
2700                 else {
2701                         /* just a partial read to be scheduled from a
2702                          * separate context
2703                          */
2704                         int slot = r10_bio->read_slot;
2705                         generic_make_request(r10_bio->devs[slot].bio);
2706                 }
2707
2708                 cond_resched();
2709                 if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
2710                         md_check_recovery(mddev);
2711         }
2712         blk_finish_plug(&plug);
2713 }
2714
2715 static int init_resync(struct r10conf *conf)
2716 {
2717         int buffs;
2718         int i;
2719
2720         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
2721         BUG_ON(conf->r10buf_pool);
2722         conf->have_replacement = 0;
2723         for (i = 0; i < conf->geo.raid_disks; i++)
2724                 if (conf->mirrors[i].replacement)
2725                         conf->have_replacement = 1;
2726         conf->r10buf_pool = mempool_create(buffs, r10buf_pool_alloc, r10buf_pool_free, conf);
2727         if (!conf->r10buf_pool)
2728                 return -ENOMEM;
2729         conf->next_resync = 0;
2730         return 0;
2731 }
2732
2733 /*
2734  * perform a "sync" on one "block"
2735  *
2736  * We need to make sure that no normal I/O request - particularly write
2737  * requests - conflict with active sync requests.
2738  *
2739  * This is achieved by tracking pending requests and a 'barrier' concept
2740  * that can be installed to exclude normal IO requests.
2741  *
2742  * Resync and recovery are handled very differently.
2743  * We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery.
2744  *
2745  * For resync, we iterate over virtual addresses, read all copies,
2746  * and update if there are differences.  If only one copy is live,
2747  * skip it.
2748  * For recovery, we iterate over physical addresses, read a good
2749  * value for each non-in_sync drive, and over-write.
2750  *
2751  * So, for recovery we may have several outstanding complex requests for a
2752  * given address, one for each out-of-sync device.  We model this by allocating
2753  * a number of r10_bio structures, one for each out-of-sync device.
2754  * As we setup these structures, we collect all bio's together into a list
2755  * which we then process collectively to add pages, and then process again
2756  * to pass to generic_make_request.
2757  *
2758  * The r10_bio structures are linked using a borrowed master_bio pointer.
2759  * This link is counted in ->remaining.  When the r10_bio that points to NULL
2760  * has its remaining count decremented to 0, the whole complex operation
2761  * is complete.
2762  *
2763  */
2764
2765 static sector_t sync_request(struct mddev *mddev, sector_t sector_nr,
2766                              int *skipped)
2767 {
2768         struct r10conf *conf = mddev->private;
2769         struct r10bio *r10_bio;
2770         struct bio *biolist = NULL, *bio;
2771         sector_t max_sector, nr_sectors;
2772         int i;
2773         int max_sync;
2774         sector_t sync_blocks;
2775         sector_t sectors_skipped = 0;
2776         int chunks_skipped = 0;
2777         sector_t chunk_mask = conf->geo.chunk_mask;
2778
2779         if (!conf->r10buf_pool)
2780                 if (init_resync(conf))
2781                         return 0;
2782
2783         /*
2784          * Allow skipping a full rebuild for incremental assembly
2785          * of a clean array, like RAID1 does.
2786          */
2787         if (mddev->bitmap == NULL &&
2788             mddev->recovery_cp == MaxSector &&
2789             mddev->reshape_position == MaxSector &&
2790             !test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
2791             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
2792             !test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
2793             conf->fullsync == 0) {
2794                 *skipped = 1;
2795                 return mddev->dev_sectors - sector_nr;
2796         }
2797
2798  skipped:
2799         max_sector = mddev->dev_sectors;
2800         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ||
2801             test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
2802                 max_sector = mddev->resync_max_sectors;
2803         if (sector_nr >= max_sector) {
2804                 /* If we aborted, we need to abort the
2805                  * sync on the 'current' bitmap chucks (there can
2806                  * be several when recovering multiple devices).
2807                  * as we may have started syncing it but not finished.
2808                  * We can find the current address in
2809                  * mddev->curr_resync, but for recovery,
2810                  * we need to convert that to several
2811                  * virtual addresses.
2812                  */
2813                 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
2814                         end_reshape(conf);
2815                         close_sync(conf);
2816                         return 0;
2817                 }
2818
2819                 if (mddev->curr_resync < max_sector) { /* aborted */
2820                         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
2821                                 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
2822                                                 &sync_blocks, 1);
2823                         else for (i = 0; i < conf->geo.raid_disks; i++) {
2824                                 sector_t sect =
2825                                         raid10_find_virt(conf, mddev->curr_resync, i);
2826                                 bitmap_end_sync(mddev->bitmap, sect,
2827                                                 &sync_blocks, 1);
2828                         }
2829                 } else {
2830                         /* completed sync */
2831                         if ((!mddev->bitmap || conf->fullsync)
2832                             && conf->have_replacement
2833                             && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
2834                                 /* Completed a full sync so the replacements
2835                                  * are now fully recovered.
2836                                  */
2837                                 for (i = 0; i < conf->geo.raid_disks; i++)
2838                                         if (conf->mirrors[i].replacement)
2839                                                 conf->mirrors[i].replacement
2840                                                         ->recovery_offset
2841                                                         = MaxSector;
2842                         }
2843                         conf->fullsync = 0;
2844                 }
2845                 bitmap_close_sync(mddev->bitmap);
2846                 close_sync(conf);
2847                 *skipped = 1;
2848                 return sectors_skipped;
2849         }
2850
2851         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
2852                 return reshape_request(mddev, sector_nr, skipped);
2853
2854         if (chunks_skipped >= conf->geo.raid_disks) {
2855                 /* if there has been nothing to do on any drive,
2856                  * then there is nothing to do at all..
2857                  */
2858                 *skipped = 1;
2859                 return (max_sector - sector_nr) + sectors_skipped;
2860         }
2861
2862         if (max_sector > mddev->resync_max)
2863                 max_sector = mddev->resync_max; /* Don't do IO beyond here */
2864
2865         /* make sure whole request will fit in a chunk - if chunks
2866          * are meaningful
2867          */
2868         if (conf->geo.near_copies < conf->geo.raid_disks &&
2869             max_sector > (sector_nr | chunk_mask))
2870                 max_sector = (sector_nr | chunk_mask) + 1;
2871
2872         /* Again, very different code for resync and recovery.
2873          * Both must result in an r10bio with a list of bios that
2874          * have bi_end_io, bi_sector, bi_bdev set,
2875          * and bi_private set to the r10bio.
2876          * For recovery, we may actually create several r10bios
2877          * with 2 bios in each, that correspond to the bios in the main one.
2878          * In this case, the subordinate r10bios link back through a
2879          * borrowed master_bio pointer, and the counter in the master
2880          * includes a ref from each subordinate.
2881          */
2882         /* First, we decide what to do and set ->bi_end_io
2883          * To end_sync_read if we want to read, and
2884          * end_sync_write if we will want to write.
2885          */
2886
2887         max_sync = RESYNC_PAGES << (PAGE_SHIFT-9);
2888         if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
2889                 /* recovery... the complicated one */
2890                 int j;
2891                 r10_bio = NULL;
2892
2893                 for (i = 0 ; i < conf->geo.raid_disks; i++) {
2894                         int still_degraded;
2895                         struct r10bio *rb2;
2896                         sector_t sect;
2897                         int must_sync;
2898                         int any_working;
2899                         struct raid10_info *mirror = &conf->mirrors[i];
2900
2901                         if ((mirror->rdev == NULL ||
2902                              test_bit(In_sync, &mirror->rdev->flags))
2903                             &&
2904                             (mirror->replacement == NULL ||
2905                              test_bit(Faulty,
2906                                       &mirror->replacement->flags)))
2907                                 continue;
2908
2909                         still_degraded = 0;
2910                         /* want to reconstruct this device */
2911                         rb2 = r10_bio;
2912                         sect = raid10_find_virt(conf, sector_nr, i);
2913                         if (sect >= mddev->resync_max_sectors) {
2914                                 /* last stripe is not complete - don't
2915                                  * try to recover this sector.
2916                                  */
2917                                 continue;
2918                         }
2919                         /* Unless we are doing a full sync, or a replacement
2920                          * we only need to recover the block if it is set in
2921                          * the bitmap
2922                          */
2923                         must_sync = bitmap_start_sync(mddev->bitmap, sect,
2924                                                       &sync_blocks, 1);
2925                         if (sync_blocks < max_sync)
2926                                 max_sync = sync_blocks;
2927                         if (!must_sync &&
2928                             mirror->replacement == NULL &&
2929                             !conf->fullsync) {
2930                                 /* yep, skip the sync_blocks here, but don't assume
2931                                  * that there will never be anything to do here
2932                                  */
2933                                 chunks_skipped = -1;
2934                                 continue;
2935                         }
2936
2937                         r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
2938                         r10_bio->state = 0;
2939                         raise_barrier(conf, rb2 != NULL);
2940                         atomic_set(&r10_bio->remaining, 0);
2941
2942                         r10_bio->master_bio = (struct bio*)rb2;
2943                         if (rb2)
2944                                 atomic_inc(&rb2->remaining);
2945                         r10_bio->mddev = mddev;
2946                         set_bit(R10BIO_IsRecover, &r10_bio->state);
2947                         r10_bio->sector = sect;
2948
2949                         raid10_find_phys(conf, r10_bio);
2950
2951                         /* Need to check if the array will still be
2952                          * degraded
2953                          */
2954                         for (j = 0; j < conf->geo.raid_disks; j++)
2955                                 if (conf->mirrors[j].rdev == NULL ||
2956                                     test_bit(Faulty, &conf->mirrors[j].rdev->flags)) {
2957                                         still_degraded = 1;
2958                                         break;
2959                                 }
2960
2961                         must_sync = bitmap_start_sync(mddev->bitmap, sect,
2962                                                       &sync_blocks, still_degraded);
2963
2964                         any_working = 0;
2965                         for (j=0; j<conf->copies;j++) {
2966                                 int k;
2967                                 int d = r10_bio->devs[j].devnum;
2968                                 sector_t from_addr, to_addr;
2969                                 struct md_rdev *rdev;
2970                                 sector_t sector, first_bad;
2971                                 int bad_sectors;
2972                                 if (!conf->mirrors[d].rdev ||
2973                                     !test_bit(In_sync, &conf->mirrors[d].rdev->flags))
2974                                         continue;
2975                                 /* This is where we read from */
2976                                 any_working = 1;
2977                                 rdev = conf->mirrors[d].rdev;
2978                                 sector = r10_bio->devs[j].addr;
2979
2980                                 if (is_badblock(rdev, sector, max_sync,
2981                                                 &first_bad, &bad_sectors)) {
2982                                         if (first_bad > sector)
2983                                                 max_sync = first_bad - sector;
2984                                         else {
2985                                                 bad_sectors -= (sector
2986                                                                 - first_bad);
2987                                                 if (max_sync > bad_sectors)
2988                                                         max_sync = bad_sectors;
2989                                                 continue;
2990                                         }
2991                                 }
2992                                 bio = r10_bio->devs[0].bio;
2993                                 bio_reset(bio);
2994                                 bio->bi_next = biolist;
2995                                 biolist = bio;
2996                                 bio->bi_private = r10_bio;
2997                                 bio->bi_end_io = end_sync_read;
2998                                 bio->bi_rw = READ;
2999                                 from_addr = r10_bio->devs[j].addr;
3000                                 bio->bi_iter.bi_sector = from_addr +
3001                                         rdev->data_offset;
3002                                 bio->bi_bdev = rdev->bdev;
3003                                 atomic_inc(&rdev->nr_pending);
3004                                 /* and we write to 'i' (if not in_sync) */
3005
3006                                 for (k=0; k<conf->copies; k++)
3007                                         if (r10_bio->devs[k].devnum == i)
3008                                                 break;
3009                                 BUG_ON(k == conf->copies);
3010                                 to_addr = r10_bio->devs[k].addr;
3011                                 r10_bio->devs[0].devnum = d;
3012                                 r10_bio->devs[0].addr = from_addr;
3013                                 r10_bio->devs[1].devnum = i;
3014                                 r10_bio->devs[1].addr = to_addr;
3015
3016                                 rdev = mirror->rdev;
3017                                 if (!test_bit(In_sync, &rdev->flags)) {
3018                                         bio = r10_bio->devs[1].bio;
3019                                         bio_reset(bio);
3020                                         bio->bi_next = biolist;
3021                                         biolist = bio;
3022                                         bio->bi_private = r10_bio;
3023                                         bio->bi_end_io = end_sync_write;
3024                                         bio->bi_rw = WRITE;
3025                                         bio->bi_iter.bi_sector = to_addr
3026                                                 + rdev->data_offset;
3027                                         bio->bi_bdev = rdev->bdev;
3028                                         atomic_inc(&r10_bio->remaining);
3029                                 } else
3030                                         r10_bio->devs[1].bio->bi_end_io = NULL;
3031
3032                                 /* and maybe write to replacement */
3033                                 bio = r10_bio->devs[1].repl_bio;
3034                                 if (bio)
3035                                         bio->bi_end_io = NULL;
3036                                 rdev = mirror->replacement;
3037                                 /* Note: if rdev != NULL, then bio
3038                                  * cannot be NULL as r10buf_pool_alloc will
3039                                  * have allocated it.
3040                                  * So the second test here is pointless.
3041                                  * But it keeps semantic-checkers happy, and
3042                                  * this comment keeps human reviewers
3043                                  * happy.
3044                                  */
3045                                 if (rdev == NULL || bio == NULL ||
3046                                     test_bit(Faulty, &rdev->flags))
3047                                         break;
3048                                 bio_reset(bio);
3049                                 bio->bi_next = biolist;
3050                                 biolist = bio;
3051                                 bio->bi_private = r10_bio;
3052                                 bio->bi_end_io = end_sync_write;
3053                                 bio->bi_rw = WRITE;
3054                                 bio->bi_iter.bi_sector = to_addr +
3055                                         rdev->data_offset;
3056                                 bio->bi_bdev = rdev->bdev;
3057                                 atomic_inc(&r10_bio->remaining);
3058                                 break;
3059                         }
3060                         if (j == conf->copies) {
3061                                 /* Cannot recover, so abort the recovery or
3062                                  * record a bad block */
3063                                 if (any_working) {
3064                                         /* problem is that there are bad blocks
3065                                          * on other device(s)
3066                                          */
3067                                         int k;
3068                                         for (k = 0; k < conf->copies; k++)
3069                                                 if (r10_bio->devs[k].devnum == i)
3070                                                         break;
3071                                         if (!test_bit(In_sync,
3072                                                       &mirror->rdev->flags)
3073                                             && !rdev_set_badblocks(
3074                                                     mirror->rdev,
3075                                                     r10_bio->devs[k].addr,
3076                                                     max_sync, 0))
3077                                                 any_working = 0;
3078                                         if (mirror->replacement &&
3079                                             !rdev_set_badblocks(
3080                                                     mirror->replacement,
3081                                                     r10_bio->devs[k].addr,
3082                                                     max_sync, 0))
3083                                                 any_working = 0;
3084                                 }
3085                                 if (!any_working)  {
3086                                         if (!test_and_set_bit(MD_RECOVERY_INTR,
3087                                                               &mddev->recovery))
3088                                                 printk(KERN_INFO "md/raid10:%s: insufficient "
3089                                                        "working devices for recovery.\n",
3090                                                        mdname(mddev));
3091                                         mirror->recovery_disabled
3092                                                 = mddev->recovery_disabled;
3093                                 }
3094                                 put_buf(r10_bio);
3095                                 if (rb2)
3096                                         atomic_dec(&rb2->remaining);
3097                                 r10_bio = rb2;
3098                                 break;
3099                         }
3100                 }
3101                 if (biolist == NULL) {
3102                         while (r10_bio) {
3103                                 struct r10bio *rb2 = r10_bio;
3104                                 r10_bio = (struct r10bio*) rb2->master_bio;
3105                                 rb2->master_bio = NULL;
3106                                 put_buf(rb2);
3107                         }
3108                         goto giveup;
3109                 }
3110         } else {
3111                 /* resync. Schedule a read for every block at this virt offset */
3112                 int count = 0;
3113
3114                 bitmap_cond_end_sync(mddev->bitmap, sector_nr);
3115
3116                 if (!bitmap_start_sync(mddev->bitmap, sector_nr,
3117                                        &sync_blocks, mddev->degraded) &&
3118                     !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED,
3119                                                  &mddev->recovery)) {
3120                         /* We can skip this block */
3121                         *skipped = 1;
3122                         return sync_blocks + sectors_skipped;
3123                 }
3124                 if (sync_blocks < max_sync)
3125                         max_sync = sync_blocks;
3126                 r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
3127                 r10_bio->state = 0;
3128
3129                 r10_bio->mddev = mddev;
3130                 atomic_set(&r10_bio->remaining, 0);
3131                 raise_barrier(conf, 0);
3132                 conf->next_resync = sector_nr;
3133
3134                 r10_bio->master_bio = NULL;
3135                 r10_bio->sector = sector_nr;
3136                 set_bit(R10BIO_IsSync, &r10_bio->state);
3137                 raid10_find_phys(conf, r10_bio);
3138                 r10_bio->sectors = (sector_nr | chunk_mask) - sector_nr + 1;
3139
3140                 for (i = 0; i < conf->copies; i++) {
3141                         int d = r10_bio->devs[i].devnum;
3142                         sector_t first_bad, sector;
3143                         int bad_sectors;
3144
3145                         if (r10_bio->devs[i].repl_bio)
3146                                 r10_bio->devs[i].repl_bio->bi_end_io = NULL;
3147
3148                         bio = r10_bio->devs[i].bio;
3149                         bio_reset(bio);
3150                         bio->bi_error = -EIO;
3151                         if (conf->mirrors[d].rdev == NULL ||
3152                             test_bit(Faulty, &conf->mirrors[d].rdev->flags))
3153                                 continue;
3154                         sector = r10_bio->devs[i].addr;
3155                         if (is_badblock(conf->mirrors[d].rdev,
3156                                         sector, max_sync,
3157                                         &first_bad, &bad_sectors)) {
3158                                 if (first_bad > sector)
3159                                         max_sync = first_bad - sector;
3160                                 else {
3161                                         bad_sectors -= (sector - first_bad);
3162                                         if (max_sync > bad_sectors)
3163                                                 max_sync = bad_sectors;
3164                                         continue;
3165                                 }
3166                         }
3167                         atomic_inc(&conf->mirrors[d].rdev->nr_pending);
3168                         atomic_inc(&r10_bio->remaining);
3169                         bio->bi_next = biolist;
3170                         biolist = bio;
3171                         bio->bi_private = r10_bio;
3172                         bio->bi_end_io = end_sync_read;
3173                         bio->bi_rw = READ;
3174                         bio->bi_iter.bi_sector = sector +
3175                                 conf->mirrors[d].rdev->data_offset;
3176                         bio->bi_bdev = conf->mirrors[d].rdev->bdev;
3177                         count++;
3178
3179                         if (conf->mirrors[d].replacement == NULL ||
3180                             test_bit(Faulty,
3181                                      &conf->mirrors[d].replacement->flags))
3182                                 continue;
3183
3184                         /* Need to set up for writing to the replacement */
3185                         bio = r10_bio->devs[i].repl_bio;
3186                         bio_reset(bio);
3187                         bio->bi_error = -EIO;
3188
3189                         sector = r10_bio->devs[i].addr;
3190                         atomic_inc(&conf->mirrors[d].rdev->nr_pending);
3191                         bio->bi_next = biolist;
3192                         biolist = bio;
3193                         bio->bi_private = r10_bio;
3194                         bio->bi_end_io = end_sync_write;
3195                         bio->bi_rw = WRITE;
3196                         bio->bi_iter.bi_sector = sector +
3197                                 conf->mirrors[d].replacement->data_offset;
3198                         bio->bi_bdev = conf->mirrors[d].replacement->bdev;
3199                         count++;
3200                 }
3201
3202                 if (count < 2) {
3203                         for (i=0; i<conf->copies; i++) {
3204                                 int d = r10_bio->devs[i].devnum;
3205                                 if (r10_bio->devs[i].bio->bi_end_io)
3206                                         rdev_dec_pending(conf->mirrors[d].rdev,
3207                                                          mddev);
3208                                 if (r10_bio->devs[i].repl_bio &&
3209                                     r10_bio->devs[i].repl_bio->bi_end_io)
3210                                         rdev_dec_pending(
3211                                                 conf->mirrors[d].replacement,
3212                                                 mddev);
3213                         }
3214                         put_buf(r10_bio);
3215                         biolist = NULL;
3216                         goto giveup;
3217                 }
3218         }
3219
3220         nr_sectors = 0;
3221         if (sector_nr + max_sync < max_sector)
3222                 max_sector = sector_nr + max_sync;
3223         do {
3224                 struct page *page;
3225                 int len = PAGE_SIZE;
3226                 if (sector_nr + (len>>9) > max_sector)
3227                         len = (max_sector - sector_nr) << 9;
3228                 if (len == 0)
3229                         break;
3230                 for (bio= biolist ; bio ; bio=bio->bi_next) {
3231                         struct bio *bio2;
3232                         page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
3233                         if (bio_add_page(bio, page, len, 0))
3234                                 continue;
3235
3236                         /* stop here */
3237                         bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
3238                         for (bio2 = biolist;
3239                              bio2 && bio2 != bio;
3240                              bio2 = bio2->bi_next) {
3241                                 /* remove last page from this bio */
3242                                 bio2->bi_vcnt--;
3243                                 bio2->bi_iter.bi_size -= len;
3244                                 bio_clear_flag(bio2, BIO_SEG_VALID);
3245                         }
3246                         goto bio_full;
3247                 }
3248                 nr_sectors += len>>9;
3249                 sector_nr += len>>9;
3250         } while (biolist->bi_vcnt < RESYNC_PAGES);
3251  bio_full:
3252         r10_bio->sectors = nr_sectors;
3253
3254         while (biolist) {
3255                 bio = biolist;
3256                 biolist = biolist->bi_next;
3257
3258                 bio->bi_next = NULL;
3259                 r10_bio = bio->bi_private;
3260                 r10_bio->sectors = nr_sectors;
3261
3262                 if (bio->bi_end_io == end_sync_read) {
3263                         md_sync_acct(bio->bi_bdev, nr_sectors);
3264                         bio->bi_error = 0;
3265                         generic_make_request(bio);
3266                 }
3267         }
3268
3269         if (sectors_skipped)
3270                 /* pretend they weren't skipped, it makes
3271                  * no important difference in this case
3272                  */
3273                 md_done_sync(mddev, sectors_skipped, 1);
3274
3275         return sectors_skipped + nr_sectors;
3276  giveup:
3277         /* There is nowhere to write, so all non-sync
3278          * drives must be failed or in resync, all drives
3279          * have a bad block, so try the next chunk...
3280          */
3281         if (sector_nr + max_sync < max_sector)
3282                 max_sector = sector_nr + max_sync;
3283
3284         sectors_skipped += (max_sector - sector_nr);
3285         chunks_skipped ++;
3286         sector_nr = max_sector;
3287         goto skipped;
3288 }
3289
3290 static sector_t
3291 raid10_size(struct mddev *mddev, sector_t sectors, int raid_disks)
3292 {
3293         sector_t size;
3294         struct r10conf *conf = mddev->private;
3295
3296         if (!raid_disks)
3297                 raid_disks = min(conf->geo.raid_disks,
3298                                  conf->prev.raid_disks);
3299         if (!sectors)
3300                 sectors = conf->dev_sectors;
3301
3302         size = sectors >> conf->geo.chunk_shift;
3303         sector_div(size, conf->geo.far_copies);
3304         size = size * raid_disks;
3305         sector_div(size, conf->geo.near_copies);
3306
3307         return size << conf->geo.chunk_shift;
3308 }
3309
3310 static void calc_sectors(struct r10conf *conf, sector_t size)
3311 {
3312         /* Calculate the number of sectors-per-device that will
3313          * actually be used, and set conf->dev_sectors and
3314          * conf->stride
3315          */
3316
3317         size = size >> conf->geo.chunk_shift;
3318         sector_div(size, conf->geo.far_copies);
3319         size = size * conf->geo.raid_disks;
3320         sector_div(size, conf->geo.near_copies);
3321         /* 'size' is now the number of chunks in the array */
3322         /* calculate "used chunks per device" */
3323         size = size * conf->copies;
3324
3325         /* We need to round up when dividing by raid_disks to
3326          * get the stride size.
3327          */
3328         size = DIV_ROUND_UP_SECTOR_T(size, conf->geo.raid_disks);
3329
3330         conf->dev_sectors = size << conf->geo.chunk_shift;
3331
3332         if (conf->geo.far_offset)
3333                 conf->geo.stride = 1 << conf->geo.chunk_shift;
3334         else {
3335                 sector_div(size, conf->geo.far_copies);
3336                 conf->geo.stride = size << conf->geo.chunk_shift;
3337         }
3338 }
3339
3340 enum geo_type {geo_new, geo_old, geo_start};
3341 static int setup_geo(struct geom *geo, struct mddev *mddev, enum geo_type new)
3342 {
3343         int nc, fc, fo;
3344         int layout, chunk, disks;
3345         switch (new) {
3346         case geo_old:
3347                 layout = mddev->layout;
3348                 chunk = mddev->chunk_sectors;
3349                 disks = mddev->raid_disks - mddev->delta_disks;
3350                 break;
3351         case geo_new:
3352                 layout = mddev->new_layout;
3353                 chunk = mddev->new_chunk_sectors;
3354                 disks = mddev->raid_disks;
3355                 break;
3356         default: /* avoid 'may be unused' warnings */
3357         case geo_start: /* new when starting reshape - raid_disks not
3358                          * updated yet. */
3359                 layout = mddev->new_layout;
3360                 chunk = mddev->new_chunk_sectors;
3361                 disks = mddev->raid_disks + mddev->delta_disks;
3362                 break;
3363         }
3364         if (layout >> 18)
3365                 return -1;
3366         if (chunk < (PAGE_SIZE >> 9) ||
3367             !is_power_of_2(chunk))
3368                 return -2;
3369         nc = layout & 255;
3370         fc = (layout >> 8) & 255;
3371         fo = layout & (1<<16);
3372         geo->raid_disks = disks;
3373         geo->near_copies = nc;
3374         geo->far_copies = fc;
3375         geo->far_offset = fo;
3376         geo->far_set_size = (layout & (1<<17)) ? disks / fc : disks;
3377         geo->chunk_mask = chunk - 1;
3378         geo->chunk_shift = ffz(~chunk);
3379         return nc*fc;
3380 }
3381
3382 static struct r10conf *setup_conf(struct mddev *mddev)
3383 {
3384         struct r10conf *conf = NULL;
3385         int err = -EINVAL;
3386         struct geom geo;
3387         int copies;
3388
3389         copies = setup_geo(&geo, mddev, geo_new);
3390
3391         if (copies == -2) {
3392                 printk(KERN_ERR "md/raid10:%s: chunk size must be "
3393                        "at least PAGE_SIZE(%ld) and be a power of 2.\n",
3394                        mdname(mddev), PAGE_SIZE);
3395                 goto out;
3396         }
3397
3398         if (copies < 2 || copies > mddev->raid_disks) {
3399                 printk(KERN_ERR "md/raid10:%s: unsupported raid10 layout: 0x%8x\n",
3400                        mdname(mddev), mddev->new_layout);
3401                 goto out;
3402         }
3403
3404         err = -ENOMEM;
3405         conf = kzalloc(sizeof(struct r10conf), GFP_KERNEL);
3406         if (!conf)
3407                 goto out;
3408
3409         /* FIXME calc properly */
3410         conf->mirrors = kzalloc(sizeof(struct raid10_info)*(mddev->raid_disks +
3411                                                             max(0,-mddev->delta_disks)),
3412                                 GFP_KERNEL);
3413         if (!conf->mirrors)
3414                 goto out;
3415
3416         conf->tmppage = alloc_page(GFP_KERNEL);
3417         if (!conf->tmppage)
3418                 goto out;
3419
3420         conf->geo = geo;
3421         conf->copies = copies;
3422         conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc,
3423                                            r10bio_pool_free, conf);
3424         if (!conf->r10bio_pool)
3425                 goto out;
3426
3427         calc_sectors(conf, mddev->dev_sectors);
3428         if (mddev->reshape_position == MaxSector) {
3429                 conf->prev = conf->geo;
3430                 conf->reshape_progress = MaxSector;
3431         } else {
3432                 if (setup_geo(&conf->prev, mddev, geo_old) != conf->copies) {
3433                         err = -EINVAL;
3434                         goto out;
3435                 }
3436                 conf->reshape_progress = mddev->reshape_position;
3437                 if (conf->prev.far_offset)
3438                         conf->prev.stride = 1 << conf->prev.chunk_shift;
3439                 else
3440                         /* far_copies must be 1 */
3441                         conf->prev.stride = conf->dev_sectors;
3442         }
3443         conf->reshape_safe = conf->reshape_progress;
3444         spin_lock_init(&conf->device_lock);
3445         INIT_LIST_HEAD(&conf->retry_list);
3446
3447         spin_lock_init(&conf->resync_lock);
3448         init_waitqueue_head(&conf->wait_barrier);
3449
3450         conf->thread = md_register_thread(raid10d, mddev, "raid10");
3451         if (!conf->thread)
3452                 goto out;
3453
3454         conf->mddev = mddev;
3455         return conf;
3456
3457  out:
3458         if (err == -ENOMEM)
3459                 printk(KERN_ERR "md/raid10:%s: couldn't allocate memory.\n",
3460                        mdname(mddev));
3461         if (conf) {
3462                 if (conf->r10bio_pool)
3463                         mempool_destroy(conf->r10bio_pool);
3464                 kfree(conf->mirrors);
3465                 safe_put_page(conf->tmppage);
3466                 kfree(conf);
3467         }
3468         return ERR_PTR(err);
3469 }
3470
3471 static int run(struct mddev *mddev)
3472 {
3473         struct r10conf *conf;
3474         int i, disk_idx, chunk_size;
3475         struct raid10_info *disk;
3476         struct md_rdev *rdev;
3477         sector_t size;
3478         sector_t min_offset_diff = 0;
3479         int first = 1;
3480         bool discard_supported = false;
3481
3482         if (mddev->private == NULL) {
3483                 conf = setup_conf(mddev);
3484                 if (IS_ERR(conf))
3485                         return PTR_ERR(conf);
3486                 mddev->private = conf;
3487         }
3488         conf = mddev->private;
3489         if (!conf)
3490                 goto out;
3491
3492         mddev->thread = conf->thread;
3493         conf->thread = NULL;
3494
3495         chunk_size = mddev->chunk_sectors << 9;
3496         if (mddev->queue) {
3497                 blk_queue_max_discard_sectors(mddev->queue,
3498                                               mddev->chunk_sectors);
3499                 blk_queue_max_write_same_sectors(mddev->queue, 0);
3500                 blk_queue_io_min(mddev->queue, chunk_size);
3501                 if (conf->geo.raid_disks % conf->geo.near_copies)
3502                         blk_queue_io_opt(mddev->queue, chunk_size * conf->geo.raid_disks);
3503                 else
3504                         blk_queue_io_opt(mddev->queue, chunk_size *
3505                                          (conf->geo.raid_disks / conf->geo.near_copies));
3506         }
3507
3508         rdev_for_each(rdev, mddev) {
3509                 long long diff;
3510                 struct request_queue *q;
3511
3512                 disk_idx = rdev->raid_disk;
3513                 if (disk_idx < 0)
3514                         continue;
3515                 if (disk_idx >= conf->geo.raid_disks &&
3516                     disk_idx >= conf->prev.raid_disks)
3517                         continue;
3518                 disk = conf->mirrors + disk_idx;
3519
3520                 if (test_bit(Replacement, &rdev->flags)) {
3521                         if (disk->replacement)
3522                                 goto out_free_conf;
3523                         disk->replacement = rdev;
3524                 } else {
3525                         if (disk->rdev)
3526                                 goto out_free_conf;
3527                         disk->rdev = rdev;
3528                 }
3529                 q = bdev_get_queue(rdev->bdev);
3530                 diff = (rdev->new_data_offset - rdev->data_offset);
3531                 if (!mddev->reshape_backwards)
3532                         diff = -diff;
3533                 if (diff < 0)
3534                         diff = 0;
3535                 if (first || diff < min_offset_diff)
3536                         min_offset_diff = diff;
3537
3538                 if (mddev->gendisk)
3539                         disk_stack_limits(mddev->gendisk, rdev->bdev,
3540                                           rdev->data_offset << 9);
3541
3542                 disk->head_position = 0;
3543
3544                 if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
3545                         discard_supported = true;
3546         }
3547
3548         if (mddev->queue) {
3549                 if (discard_supported)
3550                         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
3551                                                 mddev->queue);
3552                 else
3553                         queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
3554                                                   mddev->queue);
3555         }
3556         /* need to check that every block has at least one working mirror */
3557         if (!enough(conf, -1)) {
3558                 printk(KERN_ERR "md/raid10:%s: not enough operational mirrors.\n",
3559                        mdname(mddev));
3560                 goto out_free_conf;
3561         }
3562
3563         if (conf->reshape_progress != MaxSector) {
3564                 /* must ensure that shape change is supported */
3565                 if (conf->geo.far_copies != 1 &&
3566                     conf->geo.far_offset == 0)
3567                         goto out_free_conf;
3568                 if (conf->prev.far_copies != 1 &&
3569                     conf->prev.far_offset == 0)
3570                         goto out_free_conf;
3571         }
3572
3573         mddev->degraded = 0;
3574         for (i = 0;
3575              i < conf->geo.raid_disks
3576                      || i < conf->prev.raid_disks;
3577              i++) {
3578
3579                 disk = conf->mirrors + i;
3580
3581                 if (!disk->rdev && disk->replacement) {
3582                         /* The replacement is all we have - use it */
3583                         disk->rdev = disk->replacement;
3584                         disk->replacement = NULL;
3585                         clear_bit(Replacement, &disk->rdev->flags);
3586                 }
3587
3588                 if (!disk->rdev ||
3589                     !test_bit(In_sync, &disk->rdev->flags)) {
3590                         disk->head_position = 0;
3591                         mddev->degraded++;
3592                         if (disk->rdev &&
3593                             disk->rdev->saved_raid_disk < 0)
3594                                 conf->fullsync = 1;
3595                 }
3596                 disk->recovery_disabled = mddev->recovery_disabled - 1;
3597         }
3598
3599         if (mddev->recovery_cp != MaxSector)
3600                 printk(KERN_NOTICE "md/raid10:%s: not clean"
3601                        " -- starting background reconstruction\n",
3602                        mdname(mddev));
3603         printk(KERN_INFO
3604                 "md/raid10:%s: active with %d out of %d devices\n",
3605                 mdname(mddev), conf->geo.raid_disks - mddev->degraded,
3606                 conf->geo.raid_disks);
3607         /*
3608          * Ok, everything is just fine now
3609          */
3610         mddev->dev_sectors = conf->dev_sectors;
3611         size = raid10_size(mddev, 0, 0);
3612         md_set_array_sectors(mddev, size);
3613         mddev->resync_max_sectors = size;
3614
3615         if (mddev->queue) {
3616                 int stripe = conf->geo.raid_disks *
3617                         ((mddev->chunk_sectors << 9) / PAGE_SIZE);
3618
3619                 /* Calculate max read-ahead size.
3620                  * We need to readahead at least twice a whole stripe....
3621                  * maybe...
3622                  */
3623                 stripe /= conf->geo.near_copies;
3624                 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
3625                         mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
3626         }
3627
3628         if (md_integrity_register(mddev))
3629                 goto out_free_conf;
3630
3631         if (conf->reshape_progress != MaxSector) {
3632                 unsigned long before_length, after_length;
3633
3634                 before_length = ((1 << conf->prev.chunk_shift) *
3635                                  conf->prev.far_copies);
3636                 after_length = ((1 << conf->geo.chunk_shift) *
3637                                 conf->geo.far_copies);
3638
3639                 if (max(before_length, after_length) > min_offset_diff) {
3640                         /* This cannot work */
3641                         printk("md/raid10: offset difference not enough to continue reshape\n");
3642                         goto out_free_conf;
3643                 }
3644                 conf->offset_diff = min_offset_diff;
3645
3646                 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3647                 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
3648                 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
3649                 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
3650                 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
3651                                                         "reshape");
3652         }
3653
3654         return 0;
3655
3656 out_free_conf:
3657         md_unregister_thread(&mddev->thread);
3658         if (conf->r10bio_pool)
3659                 mempool_destroy(conf->r10bio_pool);
3660         safe_put_page(conf->tmppage);
3661         kfree(conf->mirrors);
3662         kfree(conf);
3663         mddev->private = NULL;
3664 out:
3665         return -EIO;
3666 }
3667
3668 static void raid10_free(struct mddev *mddev, void *priv)
3669 {
3670         struct r10conf *conf = priv;
3671
3672         if (conf->r10bio_pool)
3673                 mempool_destroy(conf->r10bio_pool);
3674         safe_put_page(conf->tmppage);
3675         kfree(conf->mirrors);
3676         kfree(conf->mirrors_old);
3677         kfree(conf->mirrors_new);
3678         kfree(conf);
3679 }
3680
3681 static void raid10_quiesce(struct mddev *mddev, int state)
3682 {
3683         struct r10conf *conf = mddev->private;
3684
3685         switch(state) {
3686         case 1:
3687                 raise_barrier(conf, 0);
3688                 break;
3689         case 0:
3690                 lower_barrier(conf);
3691                 break;
3692         }
3693 }
3694
3695 static int raid10_resize(struct mddev *mddev, sector_t sectors)
3696 {
3697         /* Resize of 'far' arrays is not supported.
3698          * For 'near' and 'offset' arrays we can set the
3699          * number of sectors used to be an appropriate multiple
3700          * of the chunk size.
3701          * For 'offset', this is far_copies*chunksize.
3702          * For 'near' the multiplier is the LCM of
3703          * near_copies and raid_disks.
3704          * So if far_copies > 1 && !far_offset, fail.
3705          * Else find LCM(raid_disks, near_copy)*far_copies and
3706          * multiply by chunk_size.  Then round to this number.
3707          * This is mostly done by raid10_size()
3708          */
3709         struct r10conf *conf = mddev->private;
3710         sector_t oldsize, size;
3711
3712         if (mddev->reshape_position != MaxSector)
3713                 return -EBUSY;
3714
3715         if (conf->geo.far_copies > 1 && !conf->geo.far_offset)
3716                 return -EINVAL;
3717
3718         oldsize = raid10_size(mddev, 0, 0);
3719         size = raid10_size(mddev, sectors, 0);
3720         if (mddev->external_size &&
3721             mddev->array_sectors > size)
3722                 return -EINVAL;
3723         if (mddev->bitmap) {
3724                 int ret = bitmap_resize(mddev->bitmap, size, 0, 0);
3725                 if (ret)
3726                         return ret;
3727         }
3728         md_set_array_sectors(mddev, size);
3729         set_capacity(mddev->gendisk, mddev->array_sectors);
3730         revalidate_disk(mddev->gendisk);
3731         if (sectors > mddev->dev_sectors &&
3732             mddev->recovery_cp > oldsize) {
3733                 mddev->recovery_cp = oldsize;
3734                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3735         }
3736         calc_sectors(conf, sectors);
3737         mddev->dev_sectors = conf->dev_sectors;
3738         mddev->resync_max_sectors = size;
3739         return 0;
3740 }
3741
3742 static void *raid10_takeover_raid0(struct mddev *mddev, sector_t size, int devs)
3743 {
3744         struct md_rdev *rdev;
3745         struct r10conf *conf;
3746
3747         if (mddev->degraded > 0) {
3748                 printk(KERN_ERR "md/raid10:%s: Error: degraded raid0!\n",
3749                        mdname(mddev));
3750                 return ERR_PTR(-EINVAL);
3751         }
3752         sector_div(size, devs);
3753
3754         /* Set new parameters */
3755         mddev->new_level = 10;
3756         /* new layout: far_copies = 1, near_copies = 2 */
3757         mddev->new_layout = (1<<8) + 2;
3758         mddev->new_chunk_sectors = mddev->chunk_sectors;
3759         mddev->delta_disks = mddev->raid_disks;
3760         mddev->raid_disks *= 2;
3761         /* make sure it will be not marked as dirty */
3762         mddev->recovery_cp = MaxSector;
3763         mddev->dev_sectors = size;
3764
3765         conf = setup_conf(mddev);
3766         if (!IS_ERR(conf)) {
3767                 rdev_for_each(rdev, mddev)
3768                         if (rdev->raid_disk >= 0) {
3769                                 rdev->new_raid_disk = rdev->raid_disk * 2;
3770                                 rdev->sectors = size;
3771                         }
3772                 conf->barrier = 1;
3773         }
3774
3775         return conf;
3776 }
3777
3778 static void *raid10_takeover(struct mddev *mddev)
3779 {
3780         struct r0conf *raid0_conf;
3781
3782         /* raid10 can take over:
3783          *  raid0 - providing it has only two drives
3784          */
3785         if (mddev->level == 0) {
3786                 /* for raid0 takeover only one zone is supported */
3787                 raid0_conf = mddev->private;
3788                 if (raid0_conf->nr_strip_zones > 1) {
3789                         printk(KERN_ERR "md/raid10:%s: cannot takeover raid 0"
3790                                " with more than one zone.\n",
3791                                mdname(mddev));
3792                         return ERR_PTR(-EINVAL);
3793                 }
3794                 return raid10_takeover_raid0(mddev,
3795                         raid0_conf->strip_zone->zone_end,
3796                         raid0_conf->strip_zone->nb_dev);
3797         }
3798         return ERR_PTR(-EINVAL);
3799 }
3800
3801 static int raid10_check_reshape(struct mddev *mddev)
3802 {
3803         /* Called when there is a request to change
3804          * - layout (to ->new_layout)
3805          * - chunk size (to ->new_chunk_sectors)
3806          * - raid_disks (by delta_disks)
3807          * or when trying to restart a reshape that was ongoing.
3808          *
3809          * We need to validate the request and possibly allocate
3810          * space if that might be an issue later.
3811          *
3812          * Currently we reject any reshape of a 'far' mode array,
3813          * allow chunk size to change if new is generally acceptable,
3814          * allow raid_disks to increase, and allow
3815          * a switch between 'near' mode and 'offset' mode.
3816          */
3817         struct r10conf *conf = mddev->private;
3818         struct geom geo;
3819
3820         if (conf->geo.far_copies != 1 && !conf->geo.far_offset)
3821                 return -EINVAL;
3822
3823         if (setup_geo(&geo, mddev, geo_start) != conf->copies)
3824                 /* mustn't change number of copies */
3825                 return -EINVAL;
3826         if (geo.far_copies > 1 && !geo.far_offset)
3827                 /* Cannot switch to 'far' mode */
3828                 return -EINVAL;
3829
3830         if (mddev->array_sectors & geo.chunk_mask)
3831                         /* not factor of array size */
3832                         return -EINVAL;
3833
3834         if (!enough(conf, -1))
3835                 return -EINVAL;
3836
3837         kfree(conf->mirrors_new);
3838         conf->mirrors_new = NULL;
3839         if (mddev->delta_disks > 0) {
3840                 /* allocate new 'mirrors' list */
3841                 conf->mirrors_new = kzalloc(
3842                         sizeof(struct raid10_info)
3843                         *(mddev->raid_disks +
3844                           mddev->delta_disks),
3845                         GFP_KERNEL);
3846                 if (!conf->mirrors_new)
3847                         return -ENOMEM;
3848         }
3849         return 0;
3850 }
3851
3852 /*
3853  * Need to check if array has failed when deciding whether to:
3854  *  - start an array
3855  *  - remove non-faulty devices
3856  *  - add a spare
3857  *  - allow a reshape
3858  * This determination is simple when no reshape is happening.
3859  * However if there is a reshape, we need to carefully check
3860  * both the before and after sections.
3861  * This is because some failed devices may only affect one
3862  * of the two sections, and some non-in_sync devices may
3863  * be insync in the section most affected by failed devices.
3864  */
3865 static int calc_degraded(struct r10conf *conf)
3866 {
3867         int degraded, degraded2;
3868         int i;
3869
3870         rcu_read_lock();
3871         degraded = 0;
3872         /* 'prev' section first */
3873         for (i = 0; i < conf->prev.raid_disks; i++) {
3874                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
3875                 if (!rdev || test_bit(Faulty, &rdev->flags))
3876                         degraded++;
3877                 else if (!test_bit(In_sync, &rdev->flags))
3878                         /* When we can reduce the number of devices in
3879                          * an array, this might not contribute to
3880                          * 'degraded'.  It does now.
3881                          */
3882                         degraded++;
3883         }
3884         rcu_read_unlock();
3885         if (conf->geo.raid_disks == conf->prev.raid_disks)
3886                 return degraded;
3887         rcu_read_lock();
3888         degraded2 = 0;
3889         for (i = 0; i < conf->geo.raid_disks; i++) {
3890                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
3891                 if (!rdev || test_bit(Faulty, &rdev->flags))
3892                         degraded2++;
3893                 else if (!test_bit(In_sync, &rdev->flags)) {
3894                         /* If reshape is increasing the number of devices,
3895                          * this section has already been recovered, so
3896                          * it doesn't contribute to degraded.
3897                          * else it does.
3898                          */
3899                         if (conf->geo.raid_disks <= conf->prev.raid_disks)
3900                                 degraded2++;
3901                 }
3902         }
3903         rcu_read_unlock();
3904         if (degraded2 > degraded)
3905                 return degraded2;
3906         return degraded;
3907 }
3908
3909 static int raid10_start_reshape(struct mddev *mddev)
3910 {
3911         /* A 'reshape' has been requested. This commits
3912          * the various 'new' fields and sets MD_RECOVER_RESHAPE
3913          * This also checks if there are enough spares and adds them
3914          * to the array.
3915          * We currently require enough spares to make the final
3916          * array non-degraded.  We also require that the difference
3917          * between old and new data_offset - on each device - is
3918          * enough that we never risk over-writing.
3919          */
3920
3921         unsigned long before_length, after_length;
3922         sector_t min_offset_diff = 0;
3923         int first = 1;
3924         struct geom new;
3925         struct r10conf *conf = mddev->private;
3926         struct md_rdev *rdev;
3927         int spares = 0;
3928         int ret;
3929
3930         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
3931                 return -EBUSY;
3932
3933         if (setup_geo(&new, mddev, geo_start) != conf->copies)
3934                 return -EINVAL;
3935
3936         before_length = ((1 << conf->prev.chunk_shift) *
3937                          conf->prev.far_copies);
3938         after_length = ((1 << conf->geo.chunk_shift) *
3939                         conf->geo.far_copies);
3940
3941         rdev_for_each(rdev, mddev) {
3942                 if (!test_bit(In_sync, &rdev->flags)
3943                     && !test_bit(Faulty, &rdev->flags))
3944                         spares++;
3945                 if (rdev->raid_disk >= 0) {
3946                         long long diff = (rdev->new_data_offset
3947                                           - rdev->data_offset);
3948                         if (!mddev->reshape_backwards)
3949                                 diff = -diff;
3950                         if (diff < 0)
3951                                 diff = 0;
3952                         if (first || diff < min_offset_diff)
3953                                 min_offset_diff = diff;
3954                 }
3955         }
3956
3957         if (max(before_length, after_length) > min_offset_diff)
3958                 return -EINVAL;
3959
3960         if (spares < mddev->delta_disks)
3961                 return -EINVAL;
3962
3963         conf->offset_diff = min_offset_diff;
3964         spin_lock_irq(&conf->device_lock);
3965         if (conf->mirrors_new) {
3966                 memcpy(conf->mirrors_new, conf->mirrors,
3967                        sizeof(struct raid10_info)*conf->prev.raid_disks);
3968                 smp_mb();
3969                 kfree(conf->mirrors_old);
3970                 conf->mirrors_old = conf->mirrors;
3971                 conf->mirrors = conf->mirrors_new;
3972                 conf->mirrors_new = NULL;
3973         }
3974         setup_geo(&conf->geo, mddev, geo_start);
3975         smp_mb();
3976         if (mddev->reshape_backwards) {
3977                 sector_t size = raid10_size(mddev, 0, 0);
3978                 if (size < mddev->array_sectors) {
3979                         spin_unlock_irq(&conf->device_lock);
3980                         printk(KERN_ERR "md/raid10:%s: array size must be reduce before number of disks\n",
3981                                mdname(mddev));
3982                         return -EINVAL;
3983                 }
3984                 mddev->resync_max_sectors = size;
3985                 conf->reshape_progress = size;
3986         } else
3987                 conf->reshape_progress = 0;
3988         conf->reshape_safe = conf->reshape_progress;
3989         spin_unlock_irq(&conf->device_lock);
3990
3991         if (mddev->delta_disks && mddev->bitmap) {
3992                 ret = bitmap_resize(mddev->bitmap,
3993                                     raid10_size(mddev, 0,
3994                                                 conf->geo.raid_disks),
3995                                     0, 0);
3996                 if (ret)
3997                         goto abort;
3998         }
3999         if (mddev->delta_disks > 0) {
4000                 rdev_for_each(rdev, mddev)
4001                         if (rdev->raid_disk < 0 &&
4002                             !test_bit(Faulty, &rdev->flags)) {
4003                                 if (raid10_add_disk(mddev, rdev) == 0) {
4004                                         if (rdev->raid_disk >=
4005                                             conf->prev.raid_disks)
4006                                                 set_bit(In_sync, &rdev->flags);
4007                                         else
4008                                                 rdev->recovery_offset = 0;
4009
4010                                         if (sysfs_link_rdev(mddev, rdev))
4011                                                 /* Failure here  is OK */;
4012                                 }
4013                         } else if (rdev->raid_disk >= conf->prev.raid_disks
4014                                    && !test_bit(Faulty, &rdev->flags)) {
4015                                 /* This is a spare that was manually added */
4016                                 set_bit(In_sync, &rdev->flags);
4017                         }
4018         }
4019         /* When a reshape changes the number of devices,
4020          * ->degraded is measured against the larger of the
4021          * pre and  post numbers.
4022          */
4023         spin_lock_irq(&conf->device_lock);
4024         mddev->degraded = calc_degraded(conf);
4025         spin_unlock_irq(&conf->device_lock);
4026         mddev->raid_disks = conf->geo.raid_disks;
4027         mddev->reshape_position = conf->reshape_progress;
4028         set_bit(MD_CHANGE_DEVS, &mddev->flags);
4029
4030         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4031         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
4032         clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
4033         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
4034         set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
4035
4036         mddev->sync_thread = md_register_thread(md_do_sync, mddev,
4037                                                 "reshape");
4038         if (!mddev->sync_thread) {
4039                 ret = -EAGAIN;
4040                 goto abort;
4041         }
4042         conf->reshape_checkpoint = jiffies;
4043         md_wakeup_thread(mddev->sync_thread);
4044         md_new_event(mddev);
4045         return 0;
4046
4047 abort:
4048         mddev->recovery = 0;
4049         spin_lock_irq(&conf->device_lock);
4050         conf->geo = conf->prev;
4051         mddev->raid_disks = conf->geo.raid_disks;
4052         rdev_for_each(rdev, mddev)
4053                 rdev->new_data_offset = rdev->data_offset;
4054         smp_wmb();
4055         conf->reshape_progress = MaxSector;
4056         conf->reshape_safe = MaxSector;
4057         mddev->reshape_position = MaxSector;
4058         spin_unlock_irq(&conf->device_lock);
4059         return ret;
4060 }
4061
4062 /* Calculate the last device-address that could contain
4063  * any block from the chunk that includes the array-address 's'
4064  * and report the next address.
4065  * i.e. the address returned will be chunk-aligned and after
4066  * any data that is in the chunk containing 's'.
4067  */
4068 static sector_t last_dev_address(sector_t s, struct geom *geo)
4069 {
4070         s = (s | geo->chunk_mask) + 1;
4071         s >>= geo->chunk_shift;
4072         s *= geo->near_copies;
4073         s = DIV_ROUND_UP_SECTOR_T(s, geo->raid_disks);
4074         s *= geo->far_copies;
4075         s <<= geo->chunk_shift;
4076         return s;
4077 }
4078
4079 /* Calculate the first device-address that could contain
4080  * any block from the chunk that includes the array-address 's'.
4081  * This too will be the start of a chunk
4082  */
4083 static sector_t first_dev_address(sector_t s, struct geom *geo)
4084 {
4085         s >>= geo->chunk_shift;
4086         s *= geo->near_copies;
4087         sector_div(s, geo->raid_disks);
4088         s *= geo->far_copies;
4089         s <<= geo->chunk_shift;
4090         return s;
4091 }
4092
4093 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr,
4094                                 int *skipped)
4095 {
4096         /* We simply copy at most one chunk (smallest of old and new)
4097          * at a time, possibly less if that exceeds RESYNC_PAGES,
4098          * or we hit a bad block or something.
4099          * This might mean we pause for normal IO in the middle of
4100          * a chunk, but that is not a problem was mddev->reshape_position
4101          * can record any location.
4102          *
4103          * If we will want to write to a location that isn't
4104          * yet recorded as 'safe' (i.e. in metadata on disk) then
4105          * we need to flush all reshape requests and update the metadata.
4106          *
4107          * When reshaping forwards (e.g. to more devices), we interpret
4108          * 'safe' as the earliest block which might not have been copied
4109          * down yet.  We divide this by previous stripe size and multiply
4110          * by previous stripe length to get lowest device offset that we
4111          * cannot write to yet.
4112          * We interpret 'sector_nr' as an address that we want to write to.
4113          * From this we use last_device_address() to find where we might
4114          * write to, and first_device_address on the  'safe' position.
4115          * If this 'next' write position is after the 'safe' position,
4116          * we must update the metadata to increase the 'safe' position.
4117          *
4118          * When reshaping backwards, we round in the opposite direction
4119          * and perform the reverse test:  next write position must not be
4120          * less than current safe position.
4121          *
4122          * In all this the minimum difference in data offsets
4123          * (conf->offset_diff - always positive) allows a bit of slack,
4124          * so next can be after 'safe', but not by more than offset_disk
4125          *
4126          * We need to prepare all the bios here before we start any IO
4127          * to ensure the size we choose is acceptable to all devices.
4128          * The means one for each copy for write-out and an extra one for
4129          * read-in.
4130          * We store the read-in bio in ->master_bio and the others in
4131          * ->devs[x].bio and ->devs[x].repl_bio.
4132          */
4133         struct r10conf *conf = mddev->private;
4134         struct r10bio *r10_bio;
4135         sector_t next, safe, last;
4136         int max_sectors;
4137         int nr_sectors;
4138         int s;
4139         struct md_rdev *rdev;
4140         int need_flush = 0;
4141         struct bio *blist;
4142         struct bio *bio, *read_bio;
4143         int sectors_done = 0;
4144
4145         if (sector_nr == 0) {
4146                 /* If restarting in the middle, skip the initial sectors */
4147                 if (mddev->reshape_backwards &&
4148                     conf->reshape_progress < raid10_size(mddev, 0, 0)) {
4149                         sector_nr = (raid10_size(mddev, 0, 0)
4150                                      - conf->reshape_progress);
4151                 } else if (!mddev->reshape_backwards &&
4152                            conf->reshape_progress > 0)
4153                         sector_nr = conf->reshape_progress;
4154                 if (sector_nr) {
4155                         mddev->curr_resync_completed = sector_nr;
4156                         sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4157                         *skipped = 1;
4158                         return sector_nr;
4159                 }
4160         }
4161
4162         /* We don't use sector_nr to track where we are up to
4163          * as that doesn't work well for ->reshape_backwards.
4164          * So just use ->reshape_progress.
4165          */
4166         if (mddev->reshape_backwards) {
4167                 /* 'next' is the earliest device address that we might
4168                  * write to for this chunk in the new layout
4169                  */
4170                 next = first_dev_address(conf->reshape_progress - 1,
4171                                          &conf->geo);
4172
4173                 /* 'safe' is the last device address that we might read from
4174                  * in the old layout after a restart
4175                  */
4176                 safe = last_dev_address(conf->reshape_safe - 1,
4177                                         &conf->prev);
4178
4179                 if (next + conf->offset_diff < safe)
4180                         need_flush = 1;
4181
4182                 last = conf->reshape_progress - 1;
4183                 sector_nr = last & ~(sector_t)(conf->geo.chunk_mask
4184                                                & conf->prev.chunk_mask);
4185                 if (sector_nr + RESYNC_BLOCK_SIZE/512 < last)
4186                         sector_nr = last + 1 - RESYNC_BLOCK_SIZE/512;
4187         } else {
4188                 /* 'next' is after the last device address that we
4189                  * might write to for this chunk in the new layout
4190                  */
4191                 next = last_dev_address(conf->reshape_progress, &conf->geo);
4192
4193                 /* 'safe' is the earliest device address that we might
4194                  * read from in the old layout after a restart
4195                  */
4196                 safe = first_dev_address(conf->reshape_safe, &conf->prev);
4197
4198                 /* Need to update metadata if 'next' might be beyond 'safe'
4199                  * as that would possibly corrupt data
4200                  */
4201                 if (next > safe + conf->offset_diff)
4202                         need_flush = 1;
4203
4204                 sector_nr = conf->reshape_progress;
4205                 last  = sector_nr | (conf->geo.chunk_mask
4206                                      & conf->prev.chunk_mask);
4207
4208                 if (sector_nr + RESYNC_BLOCK_SIZE/512 <= last)
4209                         last = sector_nr + RESYNC_BLOCK_SIZE/512 - 1;
4210         }
4211
4212         if (need_flush ||
4213             time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
4214                 /* Need to update reshape_position in metadata */
4215                 wait_barrier(conf);
4216                 mddev->reshape_position = conf->reshape_progress;
4217                 if (mddev->reshape_backwards)
4218                         mddev->curr_resync_completed = raid10_size(mddev, 0, 0)
4219                                 - conf->reshape_progress;
4220                 else
4221                         mddev->curr_resync_completed = conf->reshape_progress;
4222                 conf->reshape_checkpoint = jiffies;
4223                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
4224                 md_wakeup_thread(mddev->thread);
4225                 wait_event(mddev->sb_wait, mddev->flags == 0 ||
4226                            test_bit(MD_RECOVERY_INTR, &mddev->recovery));
4227                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
4228                         allow_barrier(conf);
4229                         return sectors_done;
4230                 }
4231                 conf->reshape_safe = mddev->reshape_position;
4232                 allow_barrier(conf);
4233         }
4234
4235 read_more:
4236         /* Now schedule reads for blocks from sector_nr to last */
4237         r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
4238         r10_bio->state = 0;
4239         raise_barrier(conf, sectors_done != 0);
4240         atomic_set(&r10_bio->remaining, 0);
4241         r10_bio->mddev = mddev;
4242         r10_bio->sector = sector_nr;
4243         set_bit(R10BIO_IsReshape, &r10_bio->state);
4244         r10_bio->sectors = last - sector_nr + 1;
4245         rdev = read_balance(conf, r10_bio, &max_sectors);
4246         BUG_ON(!test_bit(R10BIO_Previous, &r10_bio->state));
4247
4248         if (!rdev) {
4249                 /* Cannot read from here, so need to record bad blocks
4250                  * on all the target devices.
4251                  */
4252                 // FIXME
4253                 mempool_free(r10_bio, conf->r10buf_pool);
4254                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
4255                 return sectors_done;
4256         }
4257
4258         read_bio = bio_alloc_mddev(GFP_KERNEL, RESYNC_PAGES, mddev);
4259
4260         read_bio->bi_bdev = rdev->bdev;
4261         read_bio->bi_iter.bi_sector = (r10_bio->devs[r10_bio->read_slot].addr
4262                                + rdev->data_offset);
4263         read_bio->bi_private = r10_bio;
4264         read_bio->bi_end_io = end_sync_read;
4265         read_bio->bi_rw = READ;
4266         read_bio->bi_flags &= (~0UL << BIO_RESET_BITS);
4267         read_bio->bi_error = 0;
4268         read_bio->bi_vcnt = 0;
4269         read_bio->bi_iter.bi_size = 0;
4270         r10_bio->master_bio = read_bio;
4271         r10_bio->read_slot = r10_bio->devs[r10_bio->read_slot].devnum;
4272
4273         /* Now find the locations in the new layout */
4274         __raid10_find_phys(&conf->geo, r10_bio);
4275
4276         blist = read_bio;
4277         read_bio->bi_next = NULL;
4278
4279         for (s = 0; s < conf->copies*2; s++) {
4280                 struct bio *b;
4281                 int d = r10_bio->devs[s/2].devnum;
4282                 struct md_rdev *rdev2;
4283                 if (s&1) {
4284                         rdev2 = conf->mirrors[d].replacement;
4285                         b = r10_bio->devs[s/2].repl_bio;
4286                 } else {
4287                         rdev2 = conf->mirrors[d].rdev;
4288                         b = r10_bio->devs[s/2].bio;
4289                 }
4290                 if (!rdev2 || test_bit(Faulty, &rdev2->flags))
4291                         continue;
4292
4293                 bio_reset(b);
4294                 b->bi_bdev = rdev2->bdev;
4295                 b->bi_iter.bi_sector = r10_bio->devs[s/2].addr +
4296                         rdev2->new_data_offset;
4297                 b->bi_private = r10_bio;
4298                 b->bi_end_io = end_reshape_write;
4299                 b->bi_rw = WRITE;
4300                 b->bi_next = blist;
4301                 blist = b;
4302         }
4303
4304         /* Now add as many pages as possible to all of these bios. */
4305
4306         nr_sectors = 0;
4307         for (s = 0 ; s < max_sectors; s += PAGE_SIZE >> 9) {
4308                 struct page *page = r10_bio->devs[0].bio->bi_io_vec[s/(PAGE_SIZE>>9)].bv_page;
4309                 int len = (max_sectors - s) << 9;
4310                 if (len > PAGE_SIZE)
4311                         len = PAGE_SIZE;
4312                 for (bio = blist; bio ; bio = bio->bi_next) {
4313                         struct bio *bio2;
4314                         if (bio_add_page(bio, page, len, 0))
4315                                 continue;
4316
4317                         /* Didn't fit, must stop */
4318                         for (bio2 = blist;
4319                              bio2 && bio2 != bio;
4320                              bio2 = bio2->bi_next) {
4321                                 /* Remove last page from this bio */
4322                                 bio2->bi_vcnt--;
4323                                 bio2->bi_iter.bi_size -= len;
4324                                 bio_clear_flag(bio2, BIO_SEG_VALID);
4325                         }
4326                         goto bio_full;
4327                 }
4328                 sector_nr += len >> 9;
4329                 nr_sectors += len >> 9;
4330         }
4331 bio_full:
4332         r10_bio->sectors = nr_sectors;
4333
4334         /* Now submit the read */
4335         md_sync_acct(read_bio->bi_bdev, r10_bio->sectors);
4336         atomic_inc(&r10_bio->remaining);
4337         read_bio->bi_next = NULL;
4338         generic_make_request(read_bio);
4339         sector_nr += nr_sectors;
4340         sectors_done += nr_sectors;
4341         if (sector_nr <= last)
4342                 goto read_more;
4343
4344         /* Now that we have done the whole section we can
4345          * update reshape_progress
4346          */
4347         if (mddev->reshape_backwards)
4348                 conf->reshape_progress -= sectors_done;
4349         else
4350                 conf->reshape_progress += sectors_done;
4351
4352         return sectors_done;
4353 }
4354
4355 static void end_reshape_request(struct r10bio *r10_bio);
4356 static int handle_reshape_read_error(struct mddev *mddev,
4357                                      struct r10bio *r10_bio);
4358 static void reshape_request_write(struct mddev *mddev, struct r10bio *r10_bio)
4359 {
4360         /* Reshape read completed.  Hopefully we have a block
4361          * to write out.
4362          * If we got a read error then we do sync 1-page reads from
4363          * elsewhere until we find the data - or give up.
4364          */
4365         struct r10conf *conf = mddev->private;
4366         int s;
4367
4368         if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
4369                 if (handle_reshape_read_error(mddev, r10_bio) < 0) {
4370                         /* Reshape has been aborted */
4371                         md_done_sync(mddev, r10_bio->sectors, 0);
4372                         return;
4373                 }
4374
4375         /* We definitely have the data in the pages, schedule the
4376          * writes.
4377          */
4378         atomic_set(&r10_bio->remaining, 1);
4379         for (s = 0; s < conf->copies*2; s++) {
4380                 struct bio *b;
4381                 int d = r10_bio->devs[s/2].devnum;
4382                 struct md_rdev *rdev;
4383                 if (s&1) {
4384                         rdev = conf->mirrors[d].replacement;
4385                         b = r10_bio->devs[s/2].repl_bio;
4386                 } else {
4387                         rdev = conf->mirrors[d].rdev;
4388                         b = r10_bio->devs[s/2].bio;
4389                 }
4390                 if (!rdev || test_bit(Faulty, &rdev->flags))
4391                         continue;
4392                 atomic_inc(&rdev->nr_pending);
4393                 md_sync_acct(b->bi_bdev, r10_bio->sectors);
4394                 atomic_inc(&r10_bio->remaining);
4395                 b->bi_next = NULL;
4396                 generic_make_request(b);
4397         }
4398         end_reshape_request(r10_bio);
4399 }
4400
4401 static void end_reshape(struct r10conf *conf)
4402 {
4403         if (test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery))
4404                 return;
4405
4406         spin_lock_irq(&conf->device_lock);
4407         conf->prev = conf->geo;
4408         md_finish_reshape(conf->mddev);
4409         smp_wmb();
4410         conf->reshape_progress = MaxSector;
4411         conf->reshape_safe = MaxSector;
4412         spin_unlock_irq(&conf->device_lock);
4413
4414         /* read-ahead size must cover two whole stripes, which is
4415          * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
4416          */
4417         if (conf->mddev->queue) {
4418                 int stripe = conf->geo.raid_disks *
4419                         ((conf->mddev->chunk_sectors << 9) / PAGE_SIZE);
4420                 stripe /= conf->geo.near_copies;
4421                 if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
4422                         conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
4423         }
4424         conf->fullsync = 0;
4425 }
4426
4427 static int handle_reshape_read_error(struct mddev *mddev,
4428                                      struct r10bio *r10_bio)
4429 {
4430         /* Use sync reads to get the blocks from somewhere else */
4431         int sectors = r10_bio->sectors;
4432         struct r10conf *conf = mddev->private;
4433         struct {
4434                 struct r10bio r10_bio;
4435                 struct r10dev devs[conf->copies];
4436         } on_stack;
4437         struct r10bio *r10b = &on_stack.r10_bio;
4438         int slot = 0;
4439         int idx = 0;
4440         struct bio_vec *bvec = r10_bio->master_bio->bi_io_vec;
4441
4442         r10b->sector = r10_bio->sector;
4443         __raid10_find_phys(&conf->prev, r10b);
4444
4445         while (sectors) {
4446                 int s = sectors;
4447                 int success = 0;
4448                 int first_slot = slot;
4449
4450                 if (s > (PAGE_SIZE >> 9))
4451                         s = PAGE_SIZE >> 9;
4452
4453                 while (!success) {
4454                         int d = r10b->devs[slot].devnum;
4455                         struct md_rdev *rdev = conf->mirrors[d].rdev;
4456                         sector_t addr;
4457                         if (rdev == NULL ||
4458                             test_bit(Faulty, &rdev->flags) ||
4459                             !test_bit(In_sync, &rdev->flags))
4460                                 goto failed;
4461
4462                         addr = r10b->devs[slot].addr + idx * PAGE_SIZE;
4463                         success = sync_page_io(rdev,
4464                                                addr,
4465                                                s << 9,
4466                                                bvec[idx].bv_page,
4467                                                READ, false);
4468                         if (success)
4469                                 break;
4470                 failed:
4471                         slot++;
4472                         if (slot >= conf->copies)
4473                                 slot = 0;
4474                         if (slot == first_slot)
4475                                 break;
4476                 }
4477                 if (!success) {
4478                         /* couldn't read this block, must give up */
4479                         set_bit(MD_RECOVERY_INTR,
4480                                 &mddev->recovery);
4481                         return -EIO;
4482                 }
4483                 sectors -= s;
4484                 idx++;
4485         }
4486         return 0;
4487 }
4488
4489 static void end_reshape_write(struct bio *bio)
4490 {
4491         struct r10bio *r10_bio = bio->bi_private;
4492         struct mddev *mddev = r10_bio->mddev;
4493         struct r10conf *conf = mddev->private;
4494         int d;
4495         int slot;
4496         int repl;
4497         struct md_rdev *rdev = NULL;
4498
4499         d = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
4500         if (repl)
4501                 rdev = conf->mirrors[d].replacement;
4502         if (!rdev) {
4503                 smp_mb();
4504                 rdev = conf->mirrors[d].rdev;
4505         }
4506
4507         if (bio->bi_error) {
4508                 /* FIXME should record badblock */
4509                 md_error(mddev, rdev);
4510         }
4511
4512         rdev_dec_pending(rdev, mddev);
4513         end_reshape_request(r10_bio);
4514 }
4515
4516 static void end_reshape_request(struct r10bio *r10_bio)
4517 {
4518         if (!atomic_dec_and_test(&r10_bio->remaining))
4519                 return;
4520         md_done_sync(r10_bio->mddev, r10_bio->sectors, 1);
4521         bio_put(r10_bio->master_bio);
4522         put_buf(r10_bio);
4523 }
4524
4525 static void raid10_finish_reshape(struct mddev *mddev)
4526 {
4527         struct r10conf *conf = mddev->private;
4528
4529         if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
4530                 return;
4531
4532         if (mddev->delta_disks > 0) {
4533                 sector_t size = raid10_size(mddev, 0, 0);
4534                 md_set_array_sectors(mddev, size);
4535                 if (mddev->recovery_cp > mddev->resync_max_sectors) {
4536                         mddev->recovery_cp = mddev->resync_max_sectors;
4537                         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4538                 }
4539                 mddev->resync_max_sectors = size;
4540                 set_capacity(mddev->gendisk, mddev->array_sectors);
4541                 revalidate_disk(mddev->gendisk);
4542         } else {
4543                 int d;
4544                 for (d = conf->geo.raid_disks ;
4545                      d < conf->geo.raid_disks - mddev->delta_disks;
4546                      d++) {
4547                         struct md_rdev *rdev = conf->mirrors[d].rdev;
4548                         if (rdev)
4549                                 clear_bit(In_sync, &rdev->flags);
4550                         rdev = conf->mirrors[d].replacement;
4551                         if (rdev)
4552                                 clear_bit(In_sync, &rdev->flags);
4553                 }
4554         }
4555         mddev->layout = mddev->new_layout;
4556         mddev->chunk_sectors = 1 << conf->geo.chunk_shift;
4557         mddev->reshape_position = MaxSector;
4558         mddev->delta_disks = 0;
4559         mddev->reshape_backwards = 0;
4560 }
4561
4562 static struct md_personality raid10_personality =
4563 {
4564         .name           = "raid10",
4565         .level          = 10,
4566         .owner          = THIS_MODULE,
4567         .make_request   = make_request,
4568         .run            = run,
4569         .free           = raid10_free,
4570         .status         = status,
4571         .error_handler  = error,
4572         .hot_add_disk   = raid10_add_disk,
4573         .hot_remove_disk= raid10_remove_disk,
4574         .spare_active   = raid10_spare_active,
4575         .sync_request   = sync_request,
4576         .quiesce        = raid10_quiesce,
4577         .size           = raid10_size,
4578         .resize         = raid10_resize,
4579         .takeover       = raid10_takeover,
4580         .check_reshape  = raid10_check_reshape,
4581         .start_reshape  = raid10_start_reshape,
4582         .finish_reshape = raid10_finish_reshape,
4583         .congested      = raid10_congested,
4584 };
4585
4586 static int __init raid_init(void)
4587 {
4588         return register_md_personality(&raid10_personality);
4589 }
4590
4591 static void raid_exit(void)
4592 {
4593         unregister_md_personality(&raid10_personality);
4594 }
4595
4596 module_init(raid_init);
4597 module_exit(raid_exit);
4598 MODULE_LICENSE("GPL");
4599 MODULE_DESCRIPTION("RAID10 (striped mirror) personality for MD");
4600 MODULE_ALIAS("md-personality-9"); /* RAID10 */
4601 MODULE_ALIAS("md-raid10");
4602 MODULE_ALIAS("md-level-10");
4603
4604 module_param(max_queued_requests, int, S_IRUGO|S_IWUSR);