drivers/md/raid5.c

   1 /*
   2  * raid5.c : Multiple Devices driver for Linux
   3  *         Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
   4  *         Copyright (C) 1999, 2000 Ingo Molnar
   5  *         Copyright (C) 2002, 2003 H. Peter Anvin
   6  *
   7  * RAID-4/5/6 management functions.
   8  * Thanks to Penguin Computing for making the RAID-6 development possible
   9  * by donating a test server!
  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 /*
  22  * BITMAP UNPLUGGING:
  23  *
  24  * The sequencing for updating the bitmap reliably is a little
  25  * subtle (and I got it wrong the first time) so it deserves some
  26  * explanation.
  27  *
  28  * We group bitmap updates into batches.  Each batch has a number.
  29  * We may write out several batches at once, but that isn't very important.
  30  * conf->seq_write is the number of the last batch successfully written.
  31  * conf->seq_flush is the number of the last batch that was closed to
  32  *    new additions.
  33  * When we discover that we will need to write to any block in a stripe
  34  * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
  35  * the number of the batch it will be in. This is seq_flush+1.
  36  * When we are ready to do a write, if that batch hasn't been written yet,
  37  *   we plug the array and queue the stripe for later.
  38  * When an unplug happens, we increment bm_flush, thus closing the current
  39  *   batch.
  40  * When we notice that bm_flush > bm_write, we write out all pending updates
  41  * to the bitmap, and advance bm_write to where bm_flush was.
  42  * This may occasionally write a bit out twice, but is sure never to
  43  * miss any bits.
  44  */
  45
  46 #include <linux/blkdev.h>
  47 #include <linux/kthread.h>
  48 #include <linux/raid/pq.h>
  49 #include <linux/async_tx.h>
  50 #include <linux/module.h>
  51 #include <linux/async.h>
  52 #include <linux/seq_file.h>
  53 #include <linux/cpu.h>
  54 #include <linux/slab.h>
  55 #include <linux/ratelimit.h>
  56 #include <linux/nodemask.h>
  57 #include <linux/flex_array.h>
  58 #include <linux/sched/signal.h>
  59
  60 #include <trace/events/block.h>
  61 #include <linux/list_sort.h>
  62
  63 #include "md.h"
  64 #include "raid5.h"
  65 #include "raid0.h"
  66 #include "bitmap.h"
  67 #include "raid5-log.h"
  68
  69 #define UNSUPPORTED_MDDEV_FLAGS (1L << MD_FAILFAST_SUPPORTED)
  70
  71 #define cpu_to_group(cpu) cpu_to_node(cpu)
  72 #define ANY_GROUP NUMA_NO_NODE
  73
  74 static bool devices_handle_discard_safely = false;
  75 module_param(devices_handle_discard_safely, bool, 0644);
  76 MODULE_PARM_DESC(devices_handle_discard_safely,
  77                  "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
  78 static struct workqueue_struct *raid5_wq;
  79
  80 static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
  81 {
  82         int hash = (sect >> STRIPE_SHIFT) & HASH_MASK;
  83         return &conf->stripe_hashtbl[hash];
  84 }
  85
  86 static inline int stripe_hash_locks_hash(sector_t sect)
  87 {
  88         return (sect >> STRIPE_SHIFT) & STRIPE_HASH_LOCKS_MASK;
  89 }
  90
  91 static inline void lock_device_hash_lock(struct r5conf *conf, int hash)
  92 {
  93         spin_lock_irq(conf->hash_locks + hash);
  94         spin_lock(&conf->device_lock);
  95 }
  96
  97 static inline void unlock_device_hash_lock(struct r5conf *conf, int hash)
  98 {
  99         spin_unlock(&conf->device_lock);
 100         spin_unlock_irq(conf->hash_locks + hash);
 101 }
 102
 103 static inline void lock_all_device_hash_locks_irq(struct r5conf *conf)
 104 {
 105         int i;
 106         local_irq_disable();
 107         spin_lock(conf->hash_locks);
 108         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
 109                 spin_lock_nest_lock(conf->hash_locks + i, conf->hash_locks);
 110         spin_lock(&conf->device_lock);
 111 }
 112
 113 static inline void unlock_all_device_hash_locks_irq(struct r5conf *conf)
 114 {
 115         int i;
 116         spin_unlock(&conf->device_lock);
 117         for (i = NR_STRIPE_HASH_LOCKS; i; i--)
 118                 spin_unlock(conf->hash_locks + i - 1);
 119         local_irq_enable();
 120 }
 121
 122 /* Find first data disk in a raid6 stripe */
 123 static inline int raid6_d0(struct stripe_head *sh)
 124 {
 125         if (sh->ddf_layout)
 126                 /* ddf always start from first device */
 127                 return 0;
 128         /* md starts just after Q block */
 129         if (sh->qd_idx == sh->disks - 1)
 130                 return 0;
 131         else
 132                 return sh->qd_idx + 1;
 133 }
 134 static inline int raid6_next_disk(int disk, int raid_disks)
 135 {
 136         disk++;
 137         return (disk < raid_disks) ? disk : 0;
 138 }
 139
 140 /* When walking through the disks in a raid5, starting at raid6_d0,
 141  * We need to map each disk to a 'slot', where the data disks are slot
 142  * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
 143  * is raid_disks-1.  This help does that mapping.
 144  */
 145 static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
 146                              int *count, int syndrome_disks)
 147 {
 148         int slot = *count;
 149
 150         if (sh->ddf_layout)
 151                 (*count)++;
 152         if (idx == sh->pd_idx)
 153                 return syndrome_disks;
 154         if (idx == sh->qd_idx)
 155                 return syndrome_disks + 1;
 156         if (!sh->ddf_layout)
 157                 (*count)++;
 158         return slot;
 159 }
 160
 161 static void return_io(struct bio_list *return_bi)
 162 {
 163         struct bio *bi;
 164         while ((bi = bio_list_pop(return_bi)) != NULL) {
 165                 bi->bi_iter.bi_size = 0;
 166                 trace_block_bio_complete(bdev_get_queue(bi->bi_bdev),
 167                                          bi, 0);
 168                 bio_endio(bi);
 169         }
 170 }
 171
 172 static void print_raid5_conf (struct r5conf *conf);
 173
 174 static int stripe_operations_active(struct stripe_head *sh)
 175 {
 176         return sh->check_state || sh->reconstruct_state ||
 177                test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
 178                test_bit(STRIPE_COMPUTE_RUN, &sh->state);
 179 }
 180
 181 static bool stripe_is_lowprio(struct stripe_head *sh)
 182 {
 183         return (test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) ||
 184                 test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) &&
 185                !test_bit(STRIPE_R5C_CACHING, &sh->state);
 186 }
 187
 188 static void raid5_wakeup_stripe_thread(struct stripe_head *sh)
 189 {
 190         struct r5conf *conf = sh->raid_conf;
 191         struct r5worker_group *group;
 192         int thread_cnt;
 193         int i, cpu = sh->cpu;
 194
 195         if (!cpu_online(cpu)) {
 196                 cpu = cpumask_any(cpu_online_mask);
 197                 sh->cpu = cpu;
 198         }
 199
 200         if (list_empty(&sh->lru)) {
 201                 struct r5worker_group *group;
 202                 group = conf->worker_groups + cpu_to_group(cpu);
 203                 if (stripe_is_lowprio(sh))
 204                         list_add_tail(&sh->lru, &group->loprio_list);
 205                 else
 206                         list_add_tail(&sh->lru, &group->handle_list);
 207                 group->stripes_cnt++;
 208                 sh->group = group;
 209         }
 210
 211         if (conf->worker_cnt_per_group == 0) {
 212                 md_wakeup_thread(conf->mddev->thread);
 213                 return;
 214         }
 215
 216         group = conf->worker_groups + cpu_to_group(sh->cpu);
 217
 218         group->workers[0].working = true;
 219         /* at least one worker should run to avoid race */
 220         queue_work_on(sh->cpu, raid5_wq, &group->workers[0].work);
 221
 222         thread_cnt = group->stripes_cnt / MAX_STRIPE_BATCH - 1;
 223         /* wakeup more workers */
 224         for (i = 1; i < conf->worker_cnt_per_group && thread_cnt > 0; i++) {
 225                 if (group->workers[i].working == false) {
 226                         group->workers[i].working = true;
 227                         queue_work_on(sh->cpu, raid5_wq,
 228                                       &group->workers[i].work);
 229                         thread_cnt--;
 230                 }
 231         }
 232 }
 233
 234 static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh,
 235                               struct list_head *temp_inactive_list)
 236 {
 237         int i;
 238         int injournal = 0;      /* number of date pages with R5_InJournal */
 239
 240         BUG_ON(!list_empty(&sh->lru));
 241         BUG_ON(atomic_read(&conf->active_stripes)==0);
 242
 243         if (r5c_is_writeback(conf->log))
 244                 for (i = sh->disks; i--; )
 245                         if (test_bit(R5_InJournal, &sh->dev[i].flags))
 246                                 injournal++;
 247         /*
 248          * When quiesce in r5c write back, set STRIPE_HANDLE for stripes with
 249          * data in journal, so they are not released to cached lists
 250          */
 251         if (conf->quiesce && r5c_is_writeback(conf->log) &&
 252             !test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0) {
 253                 if (test_bit(STRIPE_R5C_CACHING, &sh->state))
 254                         r5c_make_stripe_write_out(sh);
 255                 set_bit(STRIPE_HANDLE, &sh->state);
 256         }
 257
 258         if (test_bit(STRIPE_HANDLE, &sh->state)) {
 259                 if (test_bit(STRIPE_DELAYED, &sh->state) &&
 260                     !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 261                         list_add_tail(&sh->lru, &conf->delayed_list);
 262                 else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
 263                            sh->bm_seq - conf->seq_write > 0)
 264                         list_add_tail(&sh->lru, &conf->bitmap_list);
 265                 else {
 266                         clear_bit(STRIPE_DELAYED, &sh->state);
 267                         clear_bit(STRIPE_BIT_DELAY, &sh->state);
 268                         if (conf->worker_cnt_per_group == 0) {
 269                                 if (stripe_is_lowprio(sh))
 270                                         list_add_tail(&sh->lru,
 271                                                         &conf->loprio_list);
 272                                 else
 273                                         list_add_tail(&sh->lru,
 274                                                         &conf->handle_list);
 275                         } else {
 276                                 raid5_wakeup_stripe_thread(sh);
 277                                 return;
 278                         }
 279                 }
 280                 md_wakeup_thread(conf->mddev->thread);
 281         } else {
 282                 BUG_ON(stripe_operations_active(sh));
 283                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 284                         if (atomic_dec_return(&conf->preread_active_stripes)
 285                             < IO_THRESHOLD)
 286                                 md_wakeup_thread(conf->mddev->thread);
 287                 atomic_dec(&conf->active_stripes);
 288                 if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
 289                         if (!r5c_is_writeback(conf->log))
 290                                 list_add_tail(&sh->lru, temp_inactive_list);
 291                         else {
 292                                 WARN_ON(test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags));
 293                                 if (injournal == 0)
 294                                         list_add_tail(&sh->lru, temp_inactive_list);
 295                                 else if (injournal == conf->raid_disks - conf->max_degraded) {
 296                                         /* full stripe */
 297                                         if (!test_and_set_bit(STRIPE_R5C_FULL_STRIPE, &sh->state))
 298                                                 atomic_inc(&conf->r5c_cached_full_stripes);
 299                                         if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
 300                                                 atomic_dec(&conf->r5c_cached_partial_stripes);
 301                                         list_add_tail(&sh->lru, &conf->r5c_full_stripe_list);
 302                                         r5c_check_cached_full_stripe(conf);
 303                                 } else
 304                                         /*
 305                                          * STRIPE_R5C_PARTIAL_STRIPE is set in
 306                                          * r5c_try_caching_write(). No need to
 307                                          * set it again.
 308                                          */
 309                                         list_add_tail(&sh->lru, &conf->r5c_partial_stripe_list);
 310                         }
 311                 }
 312         }
 313 }
 314
 315 static void __release_stripe(struct r5conf *conf, struct stripe_head *sh,
 316                              struct list_head *temp_inactive_list)
 317 {
 318         if (atomic_dec_and_test(&sh->count))
 319                 do_release_stripe(conf, sh, temp_inactive_list);
 320 }
 321
 322 /*
 323  * @hash could be NR_STRIPE_HASH_LOCKS, then we have a list of inactive_list
 324  *
 325  * Be careful: Only one task can add/delete stripes from temp_inactive_list at
 326  * given time. Adding stripes only takes device lock, while deleting stripes
 327  * only takes hash lock.
 328  */
 329 static void release_inactive_stripe_list(struct r5conf *conf,
 330                                          struct list_head *temp_inactive_list,
 331                                          int hash)
 332 {
 333         int size;
 334         bool do_wakeup = false;
 335         unsigned long flags;
 336
 337         if (hash == NR_STRIPE_HASH_LOCKS) {
 338                 size = NR_STRIPE_HASH_LOCKS;
 339                 hash = NR_STRIPE_HASH_LOCKS - 1;
 340         } else
 341                 size = 1;
 342         while (size) {
 343                 struct list_head *list = &temp_inactive_list[size - 1];
 344
 345                 /*
 346                  * We don't hold any lock here yet, raid5_get_active_stripe() might
 347                  * remove stripes from the list
 348                  */
 349                 if (!list_empty_careful(list)) {
 350                         spin_lock_irqsave(conf->hash_locks + hash, flags);
 351                         if (list_empty(conf->inactive_list + hash) &&
 352                             !list_empty(list))
 353                                 atomic_dec(&conf->empty_inactive_list_nr);
 354                         list_splice_tail_init(list, conf->inactive_list + hash);
 355                         do_wakeup = true;
 356                         spin_unlock_irqrestore(conf->hash_locks + hash, flags);
 357                 }
 358                 size--;
 359                 hash--;
 360         }
 361
 362         if (do_wakeup) {
 363                 wake_up(&conf->wait_for_stripe);
 364                 if (atomic_read(&conf->active_stripes) == 0)
 365                         wake_up(&conf->wait_for_quiescent);
 366                 if (conf->retry_read_aligned)
 367                         md_wakeup_thread(conf->mddev->thread);
 368         }
 369 }
 370
 371 /* should hold conf->device_lock already */
 372 static int release_stripe_list(struct r5conf *conf,
 373                                struct list_head *temp_inactive_list)
 374 {
 375         struct stripe_head *sh, *t;
 376         int count = 0;
 377         struct llist_node *head;
 378
 379         head = llist_del_all(&conf->released_stripes);
 380         head = llist_reverse_order(head);
 381         llist_for_each_entry_safe(sh, t, head, release_list) {
 382                 int hash;
 383
 384                 /* sh could be readded after STRIPE_ON_RELEASE_LIST is cleard */
 385                 smp_mb();
 386                 clear_bit(STRIPE_ON_RELEASE_LIST, &sh->state);
 387                 /*
 388                  * Don't worry the bit is set here, because if the bit is set
 389                  * again, the count is always > 1. This is true for
 390                  * STRIPE_ON_UNPLUG_LIST bit too.
 391                  */
 392                 hash = sh->hash_lock_index;
 393                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
 394                 count++;
 395         }
 396
 397         return count;
 398 }
 399
 400 void raid5_release_stripe(struct stripe_head *sh)
 401 {
 402         struct r5conf *conf = sh->raid_conf;
 403         unsigned long flags;
 404         struct list_head list;
 405         int hash;
 406         bool wakeup;
 407
 408         /* Avoid release_list until the last reference.
 409          */
 410         if (atomic_add_unless(&sh->count, -1, 1))
 411                 return;
 412
 413         if (unlikely(!conf->mddev->thread) ||
 414                 test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state))
 415                 goto slow_path;
 416         wakeup = llist_add(&sh->release_list, &conf->released_stripes);
 417         if (wakeup)
 418                 md_wakeup_thread(conf->mddev->thread);
 419         return;
 420 slow_path:
 421         local_irq_save(flags);
 422         /* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */
 423         if (atomic_dec_and_lock(&sh->count, &conf->device_lock)) {
 424                 INIT_LIST_HEAD(&list);
 425                 hash = sh->hash_lock_index;
 426                 do_release_stripe(conf, sh, &list);
 427                 spin_unlock(&conf->device_lock);
 428                 release_inactive_stripe_list(conf, &list, hash);
 429         }
 430         local_irq_restore(flags);
 431 }
 432
 433 static inline void remove_hash(struct stripe_head *sh)
 434 {
 435         pr_debug("remove_hash(), stripe %llu\n",
 436                 (unsigned long long)sh->sector);
 437
 438         hlist_del_init(&sh->hash);
 439 }
 440
 441 static inline void insert_hash(struct r5conf *conf, struct stripe_head *sh)
 442 {
 443         struct hlist_head *hp = stripe_hash(conf, sh->sector);
 444
 445         pr_debug("insert_hash(), stripe %llu\n",
 446                 (unsigned long long)sh->sector);
 447
 448         hlist_add_head(&sh->hash, hp);
 449 }
 450
 451 /* find an idle stripe, make sure it is unhashed, and return it. */
 452 static struct stripe_head *get_free_stripe(struct r5conf *conf, int hash)
 453 {
 454         struct stripe_head *sh = NULL;
 455         struct list_head *first;
 456
 457         if (list_empty(conf->inactive_list + hash))
 458                 goto out;
 459         first = (conf->inactive_list + hash)->next;
 460         sh = list_entry(first, struct stripe_head, lru);
 461         list_del_init(first);
 462         remove_hash(sh);
 463         atomic_inc(&conf->active_stripes);
 464         BUG_ON(hash != sh->hash_lock_index);
 465         if (list_empty(conf->inactive_list + hash))
 466                 atomic_inc(&conf->empty_inactive_list_nr);
 467 out:
 468         return sh;
 469 }
 470
 471 static void shrink_buffers(struct stripe_head *sh)
 472 {
 473         struct page *p;
 474         int i;
 475         int num = sh->raid_conf->pool_size;
 476
 477         for (i = 0; i < num ; i++) {
 478                 WARN_ON(sh->dev[i].page != sh->dev[i].orig_page);
 479                 p = sh->dev[i].page;
 480                 if (!p)
 481                         continue;
 482                 sh->dev[i].page = NULL;
 483                 put_page(p);
 484         }
 485
 486         if (sh->ppl_page) {
 487                 put_page(sh->ppl_page);
 488                 sh->ppl_page = NULL;
 489         }
 490 }
 491
 492 static int grow_buffers(struct stripe_head *sh, gfp_t gfp)
 493 {
 494         int i;
 495         int num = sh->raid_conf->pool_size;
 496
 497         for (i = 0; i < num; i++) {
 498                 struct page *page;
 499
 500                 if (!(page = alloc_page(gfp))) {
 501                         return 1;
 502                 }
 503                 sh->dev[i].page = page;
 504                 sh->dev[i].orig_page = page;
 505         }
 506
 507         if (raid5_has_ppl(sh->raid_conf)) {
 508                 sh->ppl_page = alloc_page(gfp);
 509                 if (!sh->ppl_page)
 510                         return 1;
 511         }
 512
 513         return 0;
 514 }
 515
 516 static void raid5_build_block(struct stripe_head *sh, int i, int previous);
 517 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
 518                             struct stripe_head *sh);
 519
 520 static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
 521 {
 522         struct r5conf *conf = sh->raid_conf;
 523         int i, seq;
 524
 525         BUG_ON(atomic_read(&sh->count) != 0);
 526         BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
 527         BUG_ON(stripe_operations_active(sh));
 528         BUG_ON(sh->batch_head);
 529
 530         pr_debug("init_stripe called, stripe %llu\n",
 531                 (unsigned long long)sector);
 532 retry:
 533         seq = read_seqcount_begin(&conf->gen_lock);
 534         sh->generation = conf->generation - previous;
 535         sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
 536         sh->sector = sector;
 537         stripe_set_idx(sector, conf, previous, sh);
 538         sh->state = 0;
 539
 540         for (i = sh->disks; i--; ) {
 541                 struct r5dev *dev = &sh->dev[i];
 542
 543                 if (dev->toread || dev->read || dev->towrite || dev->written ||
 544                     test_bit(R5_LOCKED, &dev->flags)) {
 545                         pr_err("sector=%llx i=%d %p %p %p %p %d\n",
 546                                (unsigned long long)sh->sector, i, dev->toread,
 547                                dev->read, dev->towrite, dev->written,
 548                                test_bit(R5_LOCKED, &dev->flags));
 549                         WARN_ON(1);
 550                 }
 551                 dev->flags = 0;
 552                 raid5_build_block(sh, i, previous);
 553         }
 554         if (read_seqcount_retry(&conf->gen_lock, seq))
 555                 goto retry;
 556         sh->overwrite_disks = 0;
 557         insert_hash(conf, sh);
 558         sh->cpu = smp_processor_id();
 559         set_bit(STRIPE_BATCH_READY, &sh->state);
 560 }
 561
 562 static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
 563                                          short generation)
 564 {
 565         struct stripe_head *sh;
 566
 567         pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
 568         hlist_for_each_entry(sh, stripe_hash(conf, sector), hash)
 569                 if (sh->sector == sector && sh->generation == generation)
 570                         return sh;
 571         pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
 572         return NULL;
 573 }
 574
 575 /*
 576  * Need to check if array has failed when deciding whether to:
 577  *  - start an array
 578  *  - remove non-faulty devices
 579  *  - add a spare
 580  *  - allow a reshape
 581  * This determination is simple when no reshape is happening.
 582  * However if there is a reshape, we need to carefully check
 583  * both the before and after sections.
 584  * This is because some failed devices may only affect one
 585  * of the two sections, and some non-in_sync devices may
 586  * be insync in the section most affected by failed devices.
 587  */
 588 int raid5_calc_degraded(struct r5conf *conf)
 589 {
 590         int degraded, degraded2;
 591         int i;
 592
 593         rcu_read_lock();
 594         degraded = 0;
 595         for (i = 0; i < conf->previous_raid_disks; i++) {
 596                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 597                 if (rdev && test_bit(Faulty, &rdev->flags))
 598                         rdev = rcu_dereference(conf->disks[i].replacement);
 599                 if (!rdev || test_bit(Faulty, &rdev->flags))
 600                         degraded++;
 601                 else if (test_bit(In_sync, &rdev->flags))
 602                         ;
 603                 else
 604                         /* not in-sync or faulty.
 605                          * If the reshape increases the number of devices,
 606                          * this is being recovered by the reshape, so
 607                          * this 'previous' section is not in_sync.
 608                          * If the number of devices is being reduced however,
 609                          * the device can only be part of the array if
 610                          * we are reverting a reshape, so this section will
 611                          * be in-sync.
 612                          */
 613                         if (conf->raid_disks >= conf->previous_raid_disks)
 614                                 degraded++;
 615         }
 616         rcu_read_unlock();
 617         if (conf->raid_disks == conf->previous_raid_disks)
 618                 return degraded;
 619         rcu_read_lock();
 620         degraded2 = 0;
 621         for (i = 0; i < conf->raid_disks; i++) {
 622                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 623                 if (rdev && test_bit(Faulty, &rdev->flags))
 624                         rdev = rcu_dereference(conf->disks[i].replacement);
 625                 if (!rdev || test_bit(Faulty, &rdev->flags))
 626                         degraded2++;
 627                 else if (test_bit(In_sync, &rdev->flags))
 628                         ;
 629                 else
 630                         /* not in-sync or faulty.
 631                          * If reshape increases the number of devices, this
 632                          * section has already been recovered, else it
 633                          * almost certainly hasn't.
 634                          */
 635                         if (conf->raid_disks <= conf->previous_raid_disks)
 636                                 degraded2++;
 637         }
 638         rcu_read_unlock();
 639         if (degraded2 > degraded)
 640                 return degraded2;
 641         return degraded;
 642 }
 643
 644 static int has_failed(struct r5conf *conf)
 645 {
 646         int degraded;
 647
 648         if (conf->mddev->reshape_position == MaxSector)
 649                 return conf->mddev->degraded > conf->max_degraded;
 650
 651         degraded = raid5_calc_degraded(conf);
 652         if (degraded > conf->max_degraded)
 653                 return 1;
 654         return 0;
 655 }
 656
 657 struct stripe_head *
 658 raid5_get_active_stripe(struct r5conf *conf, sector_t sector,
 659                         int previous, int noblock, int noquiesce)
 660 {
 661         struct stripe_head *sh;
 662         int hash = stripe_hash_locks_hash(sector);
 663         int inc_empty_inactive_list_flag;
 664
 665         pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
 666
 667         spin_lock_irq(conf->hash_locks + hash);
 668
 669         do {
 670                 wait_event_lock_irq(conf->wait_for_quiescent,
 671                                     conf->quiesce == 0 || noquiesce,
 672                                     *(conf->hash_locks + hash));
 673                 sh = __find_stripe(conf, sector, conf->generation - previous);
 674                 if (!sh) {
 675                         if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state)) {
 676                                 sh = get_free_stripe(conf, hash);
 677                                 if (!sh && !test_bit(R5_DID_ALLOC,
 678                                                      &conf->cache_state))
 679                                         set_bit(R5_ALLOC_MORE,
 680                                                 &conf->cache_state);
 681                         }
 682                         if (noblock && sh == NULL)
 683                                 break;
 684
 685                         r5c_check_stripe_cache_usage(conf);
 686                         if (!sh) {
 687                                 set_bit(R5_INACTIVE_BLOCKED,
 688                                         &conf->cache_state);
 689                                 r5l_wake_reclaim(conf->log, 0);
 690                                 wait_event_lock_irq(
 691                                         conf->wait_for_stripe,
 692                                         !list_empty(conf->inactive_list + hash) &&
 693                                         (atomic_read(&conf->active_stripes)
 694                                          < (conf->max_nr_stripes * 3 / 4)
 695                                          || !test_bit(R5_INACTIVE_BLOCKED,
 696                                                       &conf->cache_state)),
 697                                         *(conf->hash_locks + hash));
 698                                 clear_bit(R5_INACTIVE_BLOCKED,
 699                                           &conf->cache_state);
 700                         } else {
 701                                 init_stripe(sh, sector, previous);
 702                                 atomic_inc(&sh->count);
 703                         }
 704                 } else if (!atomic_inc_not_zero(&sh->count)) {
 705                         spin_lock(&conf->device_lock);
 706                         if (!atomic_read(&sh->count)) {
 707                                 if (!test_bit(STRIPE_HANDLE, &sh->state))
 708                                         atomic_inc(&conf->active_stripes);
 709                                 BUG_ON(list_empty(&sh->lru) &&
 710                                        !test_bit(STRIPE_EXPANDING, &sh->state));
 711                                 inc_empty_inactive_list_flag = 0;
 712                                 if (!list_empty(conf->inactive_list + hash))
 713                                         inc_empty_inactive_list_flag = 1;
 714                                 list_del_init(&sh->lru);
 715                                 if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 716                                         atomic_inc(&conf->empty_inactive_list_nr);
 717                                 if (sh->group) {
 718                                         sh->group->stripes_cnt--;
 719                                         sh->group = NULL;
 720                                 }
 721                         }
 722                         atomic_inc(&sh->count);
 723                         spin_unlock(&conf->device_lock);
 724                 }
 725         } while (sh == NULL);
 726
 727         spin_unlock_irq(conf->hash_locks + hash);
 728         return sh;
 729 }
 730
 731 static bool is_full_stripe_write(struct stripe_head *sh)
 732 {
 733         BUG_ON(sh->overwrite_disks > (sh->disks - sh->raid_conf->max_degraded));
 734         return sh->overwrite_disks == (sh->disks - sh->raid_conf->max_degraded);
 735 }
 736
 737 static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 738 {
 739         local_irq_disable();
 740         if (sh1 > sh2) {
 741                 spin_lock(&sh2->stripe_lock);
 742                 spin_lock_nested(&sh1->stripe_lock, 1);
 743         } else {
 744                 spin_lock(&sh1->stripe_lock);
 745                 spin_lock_nested(&sh2->stripe_lock, 1);
 746         }
 747 }
 748
 749 static void unlock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 750 {
 751         spin_unlock(&sh1->stripe_lock);
 752         spin_unlock(&sh2->stripe_lock);
 753         local_irq_enable();
 754 }
 755
 756 /* Only freshly new full stripe normal write stripe can be added to a batch list */
 757 static bool stripe_can_batch(struct stripe_head *sh)
 758 {
 759         struct r5conf *conf = sh->raid_conf;
 760
 761         if (conf->log || raid5_has_ppl(conf))
 762                 return false;
 763         return test_bit(STRIPE_BATCH_READY, &sh->state) &&
 764                 !test_bit(STRIPE_BITMAP_PENDING, &sh->state) &&
 765                 is_full_stripe_write(sh);
 766 }
 767
 768 /* we only do back search */
 769 static void stripe_add_to_batch_list(struct r5conf *conf, struct stripe_head *sh)
 770 {
 771         struct stripe_head *head;
 772         sector_t head_sector, tmp_sec;
 773         int hash;
 774         int dd_idx;
 775         int inc_empty_inactive_list_flag;
 776
 777         /* Don't cross chunks, so stripe pd_idx/qd_idx is the same */
 778         tmp_sec = sh->sector;
 779         if (!sector_div(tmp_sec, conf->chunk_sectors))
 780                 return;
 781         head_sector = sh->sector - STRIPE_SECTORS;
 782
 783         hash = stripe_hash_locks_hash(head_sector);
 784         spin_lock_irq(conf->hash_locks + hash);
 785         head = __find_stripe(conf, head_sector, conf->generation);
 786         if (head && !atomic_inc_not_zero(&head->count)) {
 787                 spin_lock(&conf->device_lock);
 788                 if (!atomic_read(&head->count)) {
 789                         if (!test_bit(STRIPE_HANDLE, &head->state))
 790                                 atomic_inc(&conf->active_stripes);
 791                         BUG_ON(list_empty(&head->lru) &&
 792                                !test_bit(STRIPE_EXPANDING, &head->state));
 793                         inc_empty_inactive_list_flag = 0;
 794                         if (!list_empty(conf->inactive_list + hash))
 795                                 inc_empty_inactive_list_flag = 1;
 796                         list_del_init(&head->lru);
 797                         if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 798                                 atomic_inc(&conf->empty_inactive_list_nr);
 799                         if (head->group) {
 800                                 head->group->stripes_cnt--;
 801                                 head->group = NULL;
 802                         }
 803                 }
 804                 atomic_inc(&head->count);
 805                 spin_unlock(&conf->device_lock);
 806         }
 807         spin_unlock_irq(conf->hash_locks + hash);
 808
 809         if (!head)
 810                 return;
 811         if (!stripe_can_batch(head))
 812                 goto out;
 813
 814         lock_two_stripes(head, sh);
 815         /* clear_batch_ready clear the flag */
 816         if (!stripe_can_batch(head) || !stripe_can_batch(sh))
 817                 goto unlock_out;
 818
 819         if (sh->batch_head)
 820                 goto unlock_out;
 821
 822         dd_idx = 0;
 823         while (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
 824                 dd_idx++;
 825         if (head->dev[dd_idx].towrite->bi_opf != sh->dev[dd_idx].towrite->bi_opf ||
 826             bio_op(head->dev[dd_idx].towrite) != bio_op(sh->dev[dd_idx].towrite))
 827                 goto unlock_out;
 828
 829         if (head->batch_head) {
 830                 spin_lock(&head->batch_head->batch_lock);
 831                 /* This batch list is already running */
 832                 if (!stripe_can_batch(head)) {
 833                         spin_unlock(&head->batch_head->batch_lock);
 834                         goto unlock_out;
 835                 }
 836
 837                 /*
 838                  * at this point, head's BATCH_READY could be cleared, but we
 839                  * can still add the stripe to batch list
 840                  */
 841                 list_add(&sh->batch_list, &head->batch_list);
 842                 spin_unlock(&head->batch_head->batch_lock);
 843
 844                 sh->batch_head = head->batch_head;
 845         } else {
 846                 head->batch_head = head;
 847                 sh->batch_head = head->batch_head;
 848                 spin_lock(&head->batch_lock);
 849                 list_add_tail(&sh->batch_list, &head->batch_list);
 850                 spin_unlock(&head->batch_lock);
 851         }
 852
 853         if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 854                 if (atomic_dec_return(&conf->preread_active_stripes)
 855                     < IO_THRESHOLD)
 856                         md_wakeup_thread(conf->mddev->thread);
 857
 858         if (test_and_clear_bit(STRIPE_BIT_DELAY, &sh->state)) {
 859                 int seq = sh->bm_seq;
 860                 if (test_bit(STRIPE_BIT_DELAY, &sh->batch_head->state) &&
 861                     sh->batch_head->bm_seq > seq)
 862                         seq = sh->batch_head->bm_seq;
 863                 set_bit(STRIPE_BIT_DELAY, &sh->batch_head->state);
 864                 sh->batch_head->bm_seq = seq;
 865         }
 866
 867         atomic_inc(&sh->count);
 868 unlock_out:
 869         unlock_two_stripes(head, sh);
 870 out:
 871         raid5_release_stripe(head);
 872 }
 873
 874 /* Determine if 'data_offset' or 'new_data_offset' should be used
 875  * in this stripe_head.
 876  */
 877 static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
 878 {
 879         sector_t progress = conf->reshape_progress;
 880         /* Need a memory barrier to make sure we see the value
 881          * of conf->generation, or ->data_offset that was set before
 882          * reshape_progress was updated.
 883          */
 884         smp_rmb();
 885         if (progress == MaxSector)
 886                 return 0;
 887         if (sh->generation == conf->generation - 1)
 888                 return 0;
 889         /* We are in a reshape, and this is a new-generation stripe,
 890          * so use new_data_offset.
 891          */
 892         return 1;
 893 }
 894
 895 static void dispatch_bio_list(struct bio_list *tmp)
 896 {
 897         struct bio *bio;
 898
 899         while ((bio = bio_list_pop(tmp)))
 900                 generic_make_request(bio);
 901 }
 902
 903 static int cmp_stripe(void *priv, struct list_head *a, struct list_head *b)
 904 {
 905         const struct r5pending_data *da = list_entry(a,
 906                                 struct r5pending_data, sibling);
 907         const struct r5pending_data *db = list_entry(b,
 908                                 struct r5pending_data, sibling);
 909         if (da->sector > db->sector)
 910                 return 1;
 911         if (da->sector < db->sector)
 912                 return -1;
 913         return 0;
 914 }
 915
 916 static void dispatch_defer_bios(struct r5conf *conf, int target,
 917                                 struct bio_list *list)
 918 {
 919         struct r5pending_data *data;
 920         struct list_head *first, *next = NULL;
 921         int cnt = 0;
 922
 923         if (conf->pending_data_cnt == 0)
 924                 return;
 925
 926         list_sort(NULL, &conf->pending_list, cmp_stripe);
 927
 928         first = conf->pending_list.next;
 929
 930         /* temporarily move the head */
 931         if (conf->next_pending_data)
 932                 list_move_tail(&conf->pending_list,
 933                                 &conf->next_pending_data->sibling);
 934
 935         while (!list_empty(&conf->pending_list)) {
 936                 data = list_first_entry(&conf->pending_list,
 937                         struct r5pending_data, sibling);
 938                 if (&data->sibling == first)
 939                         first = data->sibling.next;
 940                 next = data->sibling.next;
 941
 942                 bio_list_merge(list, &data->bios);
 943                 list_move(&data->sibling, &conf->free_list);
 944                 cnt++;
 945                 if (cnt >= target)
 946                         break;
 947         }
 948         conf->pending_data_cnt -= cnt;
 949         BUG_ON(conf->pending_data_cnt < 0 || cnt < target);
 950
 951         if (next != &conf->pending_list)
 952                 conf->next_pending_data = list_entry(next,
 953                                 struct r5pending_data, sibling);
 954         else
 955                 conf->next_pending_data = NULL;
 956         /* list isn't empty */
 957         if (first != &conf->pending_list)
 958                 list_move_tail(&conf->pending_list, first);
 959 }
 960
 961 static void flush_deferred_bios(struct r5conf *conf)
 962 {
 963         struct bio_list tmp = BIO_EMPTY_LIST;
 964
 965         if (conf->pending_data_cnt == 0)
 966                 return;
 967
 968         spin_lock(&conf->pending_bios_lock);
 969         dispatch_defer_bios(conf, conf->pending_data_cnt, &tmp);
 970         BUG_ON(conf->pending_data_cnt != 0);
 971         spin_unlock(&conf->pending_bios_lock);
 972
 973         dispatch_bio_list(&tmp);
 974 }
 975
 976 static void defer_issue_bios(struct r5conf *conf, sector_t sector,
 977                                 struct bio_list *bios)
 978 {
 979         struct bio_list tmp = BIO_EMPTY_LIST;
 980         struct r5pending_data *ent;
 981
 982         spin_lock(&conf->pending_bios_lock);
 983         ent = list_first_entry(&conf->free_list, struct r5pending_data,
 984                                                         sibling);
 985         list_move_tail(&ent->sibling, &conf->pending_list);
 986         ent->sector = sector;
 987         bio_list_init(&ent->bios);
 988         bio_list_merge(&ent->bios, bios);
 989         conf->pending_data_cnt++;
 990         if (conf->pending_data_cnt >= PENDING_IO_MAX)
 991                 dispatch_defer_bios(conf, PENDING_IO_ONE_FLUSH, &tmp);
 992
 993         spin_unlock(&conf->pending_bios_lock);
 994
 995         dispatch_bio_list(&tmp);
 996 }
 997
 998 static void
 999 raid5_end_read_request(struct bio *bi);
1000 static void
1001 raid5_end_write_request(struct bio *bi);
1002
1003 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
1004 {
1005         struct r5conf *conf = sh->raid_conf;
1006         int i, disks = sh->disks;
1007         struct stripe_head *head_sh = sh;
1008         struct bio_list pending_bios = BIO_EMPTY_LIST;
1009         bool should_defer;
1010
1011         might_sleep();
1012
1013         if (log_stripe(sh, s) == 0)
1014                 return;
1015
1016         should_defer = conf->batch_bio_dispatch && conf->group_cnt;
1017
1018         for (i = disks; i--; ) {
1019                 int op, op_flags = 0;
1020                 int replace_only = 0;
1021                 struct bio *bi, *rbi;
1022                 struct md_rdev *rdev, *rrdev = NULL;
1023
1024                 sh = head_sh;
1025                 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
1026                         op = REQ_OP_WRITE;
1027                         if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
1028                                 op_flags = REQ_FUA;
1029                         if (test_bit(R5_Discard, &sh->dev[i].flags))
1030                                 op = REQ_OP_DISCARD;
1031                 } else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1032                         op = REQ_OP_READ;
1033                 else if (test_and_clear_bit(R5_WantReplace,
1034                                             &sh->dev[i].flags)) {
1035                         op = REQ_OP_WRITE;
1036                         replace_only = 1;
1037                 } else
1038                         continue;
1039                 if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
1040                         op_flags |= REQ_SYNC;
1041
1042 again:
1043                 bi = &sh->dev[i].req;
1044                 rbi = &sh->dev[i].rreq; /* For writing to replacement */
1045
1046                 rcu_read_lock();
1047                 rrdev = rcu_dereference(conf->disks[i].replacement);
1048                 smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
1049                 rdev = rcu_dereference(conf->disks[i].rdev);
1050                 if (!rdev) {
1051                         rdev = rrdev;
1052                         rrdev = NULL;
1053                 }
1054                 if (op_is_write(op)) {
1055                         if (replace_only)
1056                                 rdev = NULL;
1057                         if (rdev == rrdev)
1058                                 /* We raced and saw duplicates */
1059                                 rrdev = NULL;
1060                 } else {
1061                         if (test_bit(R5_ReadRepl, &head_sh->dev[i].flags) && rrdev)
1062                                 rdev = rrdev;
1063                         rrdev = NULL;
1064                 }
1065
1066                 if (rdev && test_bit(Faulty, &rdev->flags))
1067                         rdev = NULL;
1068                 if (rdev)
1069                         atomic_inc(&rdev->nr_pending);
1070                 if (rrdev && test_bit(Faulty, &rrdev->flags))
1071                         rrdev = NULL;
1072                 if (rrdev)
1073                         atomic_inc(&rrdev->nr_pending);
1074                 rcu_read_unlock();
1075
1076                 /* We have already checked bad blocks for reads.  Now
1077                  * need to check for writes.  We never accept write errors
1078                  * on the replacement, so we don't to check rrdev.
1079                  */
1080                 while (op_is_write(op) && rdev &&
1081                        test_bit(WriteErrorSeen, &rdev->flags)) {
1082                         sector_t first_bad;
1083                         int bad_sectors;
1084                         int bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
1085                                               &first_bad, &bad_sectors);
1086                         if (!bad)
1087                                 break;
1088
1089                         if (bad < 0) {
1090                                 set_bit(BlockedBadBlocks, &rdev->flags);
1091                                 if (!conf->mddev->external &&
1092                                     conf->mddev->sb_flags) {
1093                                         /* It is very unlikely, but we might
1094                                          * still need to write out the
1095                                          * bad block log - better give it
1096                                          * a chance*/
1097                                         md_check_recovery(conf->mddev);
1098                                 }
1099                                 /*
1100                                  * Because md_wait_for_blocked_rdev
1101                                  * will dec nr_pending, we must
1102                                  * increment it first.
1103                                  */
1104                                 atomic_inc(&rdev->nr_pending);
1105                                 md_wait_for_blocked_rdev(rdev, conf->mddev);
1106                         } else {
1107                                 /* Acknowledged bad block - skip the write */
1108                                 rdev_dec_pending(rdev, conf->mddev);
1109                                 rdev = NULL;
1110                         }
1111                 }
1112
1113                 if (rdev) {
1114                         if (s->syncing || s->expanding || s->expanded
1115                             || s->replacing)
1116                                 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
1117
1118                         set_bit(STRIPE_IO_STARTED, &sh->state);
1119
1120                         bi->bi_bdev = rdev->bdev;
1121                         bio_set_op_attrs(bi, op, op_flags);
1122                         bi->bi_end_io = op_is_write(op)
1123                                 ? raid5_end_write_request
1124                                 : raid5_end_read_request;
1125                         bi->bi_private = sh;
1126
1127                         pr_debug("%s: for %llu schedule op %d on disc %d\n",
1128                                 __func__, (unsigned long long)sh->sector,
1129                                 bi->bi_opf, i);
1130                         atomic_inc(&sh->count);
1131                         if (sh != head_sh)
1132                                 atomic_inc(&head_sh->count);
1133                         if (use_new_offset(conf, sh))
1134                                 bi->bi_iter.bi_sector = (sh->sector
1135                                                  + rdev->new_data_offset);
1136                         else
1137                                 bi->bi_iter.bi_sector = (sh->sector
1138                                                  + rdev->data_offset);
1139                         if (test_bit(R5_ReadNoMerge, &head_sh->dev[i].flags))
1140                                 bi->bi_opf |= REQ_NOMERGE;
1141
1142                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1143                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1144
1145                         if (!op_is_write(op) &&
1146                             test_bit(R5_InJournal, &sh->dev[i].flags))
1147                                 /*
1148                                  * issuing read for a page in journal, this
1149                                  * must be preparing for prexor in rmw; read
1150                                  * the data into orig_page
1151                                  */
1152                                 sh->dev[i].vec.bv_page = sh->dev[i].orig_page;
1153                         else
1154                                 sh->dev[i].vec.bv_page = sh->dev[i].page;
1155                         bi->bi_vcnt = 1;
1156                         bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1157                         bi->bi_io_vec[0].bv_offset = 0;
1158                         bi->bi_iter.bi_size = STRIPE_SIZE;
1159                         /*
1160                          * If this is discard request, set bi_vcnt 0. We don't
1161                          * want to confuse SCSI because SCSI will replace payload
1162                          */
1163                         if (op == REQ_OP_DISCARD)
1164                                 bi->bi_vcnt = 0;
1165                         if (rrdev)
1166                                 set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
1167
1168                         if (conf->mddev->gendisk)
1169                                 trace_block_bio_remap(bdev_get_queue(bi->bi_bdev),
1170                                                       bi, disk_devt(conf->mddev->gendisk),
1171                                                       sh->dev[i].sector);
1172                         if (should_defer && op_is_write(op))
1173                                 bio_list_add(&pending_bios, bi);
1174                         else
1175                                 generic_make_request(bi);
1176                 }
1177                 if (rrdev) {
1178                         if (s->syncing || s->expanding || s->expanded
1179                             || s->replacing)
1180                                 md_sync_acct(rrdev->bdev, STRIPE_SECTORS);
1181
1182                         set_bit(STRIPE_IO_STARTED, &sh->state);
1183
1184                         rbi->bi_bdev = rrdev->bdev;
1185                         bio_set_op_attrs(rbi, op, op_flags);
1186                         BUG_ON(!op_is_write(op));
1187                         rbi->bi_end_io = raid5_end_write_request;
1188                         rbi->bi_private = sh;
1189
1190                         pr_debug("%s: for %llu schedule op %d on "
1191                                  "replacement disc %d\n",
1192                                 __func__, (unsigned long long)sh->sector,
1193                                 rbi->bi_opf, i);
1194                         atomic_inc(&sh->count);
1195                         if (sh != head_sh)
1196                                 atomic_inc(&head_sh->count);
1197                         if (use_new_offset(conf, sh))
1198                                 rbi->bi_iter.bi_sector = (sh->sector
1199                                                   + rrdev->new_data_offset);
1200                         else
1201                                 rbi->bi_iter.bi_sector = (sh->sector
1202                                                   + rrdev->data_offset);
1203                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1204                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1205                         sh->dev[i].rvec.bv_page = sh->dev[i].page;
1206                         rbi->bi_vcnt = 1;
1207                         rbi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1208                         rbi->bi_io_vec[0].bv_offset = 0;
1209                         rbi->bi_iter.bi_size = STRIPE_SIZE;
1210                         /*
1211                          * If this is discard request, set bi_vcnt 0. We don't
1212                          * want to confuse SCSI because SCSI will replace payload
1213                          */
1214                         if (op == REQ_OP_DISCARD)
1215                                 rbi->bi_vcnt = 0;
1216                         if (conf->mddev->gendisk)
1217                                 trace_block_bio_remap(bdev_get_queue(rbi->bi_bdev),
1218                                                       rbi, disk_devt(conf->mddev->gendisk),
1219                                                       sh->dev[i].sector);
1220                         if (should_defer && op_is_write(op))
1221                                 bio_list_add(&pending_bios, rbi);
1222                         else
1223                                 generic_make_request(rbi);
1224                 }
1225                 if (!rdev && !rrdev) {
1226                         if (op_is_write(op))
1227                                 set_bit(STRIPE_DEGRADED, &sh->state);
1228                         pr_debug("skip op %d on disc %d for sector %llu\n",
1229                                 bi->bi_opf, i, (unsigned long long)sh->sector);
1230                         clear_bit(R5_LOCKED, &sh->dev[i].flags);
1231                         set_bit(STRIPE_HANDLE, &sh->state);
1232                 }
1233
1234                 if (!head_sh->batch_head)
1235                         continue;
1236                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1237                                       batch_list);
1238                 if (sh != head_sh)
1239                         goto again;
1240         }
1241
1242         if (should_defer && !bio_list_empty(&pending_bios))
1243                 defer_issue_bios(conf, head_sh->sector, &pending_bios);
1244 }
1245
1246 static struct dma_async_tx_descriptor *
1247 async_copy_data(int frombio, struct bio *bio, struct page **page,
1248         sector_t sector, struct dma_async_tx_descriptor *tx,
1249         struct stripe_head *sh, int no_skipcopy)
1250 {
1251         struct bio_vec bvl;
1252         struct bvec_iter iter;
1253         struct page *bio_page;
1254         int page_offset;
1255         struct async_submit_ctl submit;
1256         enum async_tx_flags flags = 0;
1257
1258         if (bio->bi_iter.bi_sector >= sector)
1259                 page_offset = (signed)(bio->bi_iter.bi_sector - sector) * 512;
1260         else
1261                 page_offset = (signed)(sector - bio->bi_iter.bi_sector) * -512;
1262
1263         if (frombio)
1264                 flags |= ASYNC_TX_FENCE;
1265         init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
1266
1267         bio_for_each_segment(bvl, bio, iter) {
1268                 int len = bvl.bv_len;
1269                 int clen;
1270                 int b_offset = 0;
1271
1272                 if (page_offset < 0) {
1273                         b_offset = -page_offset;
1274                         page_offset += b_offset;
1275                         len -= b_offset;
1276                 }
1277
1278                 if (len > 0 && page_offset + len > STRIPE_SIZE)
1279                         clen = STRIPE_SIZE - page_offset;
1280                 else
1281                         clen = len;
1282
1283                 if (clen > 0) {
1284                         b_offset += bvl.bv_offset;
1285                         bio_page = bvl.bv_page;
1286                         if (frombio) {
1287                                 if (sh->raid_conf->skip_copy &&
1288                                     b_offset == 0 && page_offset == 0 &&
1289                                     clen == STRIPE_SIZE &&
1290                                     !no_skipcopy)
1291                                         *page = bio_page;
1292                                 else
1293                                         tx = async_memcpy(*page, bio_page, page_offset,
1294                                                   b_offset, clen, &submit);
1295                         } else
1296                                 tx = async_memcpy(bio_page, *page, b_offset,
1297                                                   page_offset, clen, &submit);
1298                 }
1299                 /* chain the operations */
1300                 submit.depend_tx = tx;
1301
1302                 if (clen < len) /* hit end of page */
1303                         break;
1304                 page_offset +=  len;
1305         }
1306
1307         return tx;
1308 }
1309
1310 static void ops_complete_biofill(void *stripe_head_ref)
1311 {
1312         struct stripe_head *sh = stripe_head_ref;
1313         struct bio_list return_bi = BIO_EMPTY_LIST;
1314         int i;
1315
1316         pr_debug("%s: stripe %llu\n", __func__,
1317                 (unsigned long long)sh->sector);
1318
1319         /* clear completed biofills */
1320         for (i = sh->disks; i--; ) {
1321                 struct r5dev *dev = &sh->dev[i];
1322
1323                 /* acknowledge completion of a biofill operation */
1324                 /* and check if we need to reply to a read request,
1325                  * new R5_Wantfill requests are held off until
1326                  * !STRIPE_BIOFILL_RUN
1327                  */
1328                 if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
1329                         struct bio *rbi, *rbi2;
1330
1331                         BUG_ON(!dev->read);
1332                         rbi = dev->read;
1333                         dev->read = NULL;
1334                         while (rbi && rbi->bi_iter.bi_sector <
1335                                 dev->sector + STRIPE_SECTORS) {
1336                                 rbi2 = r5_next_bio(rbi, dev->sector);
1337                                 if (!raid5_dec_bi_active_stripes(rbi))
1338                                         bio_list_add(&return_bi, rbi);
1339                                 rbi = rbi2;
1340                         }
1341                 }
1342         }
1343         clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
1344
1345         return_io(&return_bi);
1346
1347         set_bit(STRIPE_HANDLE, &sh->state);
1348         raid5_release_stripe(sh);
1349 }
1350
1351 static void ops_run_biofill(struct stripe_head *sh)
1352 {
1353         struct dma_async_tx_descriptor *tx = NULL;
1354         struct async_submit_ctl submit;
1355         int i;
1356
1357         BUG_ON(sh->batch_head);
1358         pr_debug("%s: stripe %llu\n", __func__,
1359                 (unsigned long long)sh->sector);
1360
1361         for (i = sh->disks; i--; ) {
1362                 struct r5dev *dev = &sh->dev[i];
1363                 if (test_bit(R5_Wantfill, &dev->flags)) {
1364                         struct bio *rbi;
1365                         spin_lock_irq(&sh->stripe_lock);
1366                         dev->read = rbi = dev->toread;
1367                         dev->toread = NULL;
1368                         spin_unlock_irq(&sh->stripe_lock);
1369                         while (rbi && rbi->bi_iter.bi_sector <
1370                                 dev->sector + STRIPE_SECTORS) {
1371                                 tx = async_copy_data(0, rbi, &dev->page,
1372                                                      dev->sector, tx, sh, 0);
1373                                 rbi = r5_next_bio(rbi, dev->sector);
1374                         }
1375                 }
1376         }
1377
1378         atomic_inc(&sh->count);
1379         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
1380         async_trigger_callback(&submit);
1381 }
1382
1383 static void mark_target_uptodate(struct stripe_head *sh, int target)
1384 {
1385         struct r5dev *tgt;
1386
1387         if (target < 0)
1388                 return;
1389
1390         tgt = &sh->dev[target];
1391         set_bit(R5_UPTODATE, &tgt->flags);
1392         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1393         clear_bit(R5_Wantcompute, &tgt->flags);
1394 }
1395
1396 static void ops_complete_compute(void *stripe_head_ref)
1397 {
1398         struct stripe_head *sh = stripe_head_ref;
1399
1400         pr_debug("%s: stripe %llu\n", __func__,
1401                 (unsigned long long)sh->sector);
1402
1403         /* mark the computed target(s) as uptodate */
1404         mark_target_uptodate(sh, sh->ops.target);
1405         mark_target_uptodate(sh, sh->ops.target2);
1406
1407         clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
1408         if (sh->check_state == check_state_compute_run)
1409                 sh->check_state = check_state_compute_result;
1410         set_bit(STRIPE_HANDLE, &sh->state);
1411         raid5_release_stripe(sh);
1412 }
1413
1414 /* return a pointer to the address conversion region of the scribble buffer */
1415 static addr_conv_t *to_addr_conv(struct stripe_head *sh,
1416                                  struct raid5_percpu *percpu, int i)
1417 {
1418         void *addr;
1419
1420         addr = flex_array_get(percpu->scribble, i);
1421         return addr + sizeof(struct page *) * (sh->disks + 2);
1422 }
1423
1424 /* return a pointer to the address conversion region of the scribble buffer */
1425 static struct page **to_addr_page(struct raid5_percpu *percpu, int i)
1426 {
1427         void *addr;
1428
1429         addr = flex_array_get(percpu->scribble, i);
1430         return addr;
1431 }
1432
1433 static struct dma_async_tx_descriptor *
1434 ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
1435 {
1436         int disks = sh->disks;
1437         struct page **xor_srcs = to_addr_page(percpu, 0);
1438         int target = sh->ops.target;
1439         struct r5dev *tgt = &sh->dev[target];
1440         struct page *xor_dest = tgt->page;
1441         int count = 0;
1442         struct dma_async_tx_descriptor *tx;
1443         struct async_submit_ctl submit;
1444         int i;
1445
1446         BUG_ON(sh->batch_head);
1447
1448         pr_debug("%s: stripe %llu block: %d\n",
1449                 __func__, (unsigned long long)sh->sector, target);
1450         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1451
1452         for (i = disks; i--; )
1453                 if (i != target)
1454                         xor_srcs[count++] = sh->dev[i].page;
1455
1456         atomic_inc(&sh->count);
1457
1458         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
1459                           ops_complete_compute, sh, to_addr_conv(sh, percpu, 0));
1460         if (unlikely(count == 1))
1461                 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
1462         else
1463                 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1464
1465         return tx;
1466 }
1467
1468 /* set_syndrome_sources - populate source buffers for gen_syndrome
1469  * @srcs - (struct page *) array of size sh->disks
1470  * @sh - stripe_head to parse
1471  *
1472  * Populates srcs in proper layout order for the stripe and returns the
1473  * 'count' of sources to be used in a call to async_gen_syndrome.  The P
1474  * destination buffer is recorded in srcs[count] and the Q destination
1475  * is recorded in srcs[count+1]].
1476  */
1477 static int set_syndrome_sources(struct page **srcs,
1478                                 struct stripe_head *sh,
1479                                 int srctype)
1480 {
1481         int disks = sh->disks;
1482         int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
1483         int d0_idx = raid6_d0(sh);
1484         int count;
1485         int i;
1486
1487         for (i = 0; i < disks; i++)
1488                 srcs[i] = NULL;
1489
1490         count = 0;
1491         i = d0_idx;
1492         do {
1493                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1494                 struct r5dev *dev = &sh->dev[i];
1495
1496                 if (i == sh->qd_idx || i == sh->pd_idx ||
1497                     (srctype == SYNDROME_SRC_ALL) ||
1498                     (srctype == SYNDROME_SRC_WANT_DRAIN &&
1499                      (test_bit(R5_Wantdrain, &dev->flags) ||
1500                       test_bit(R5_InJournal, &dev->flags))) ||
1501                     (srctype == SYNDROME_SRC_WRITTEN &&
1502                      (dev->written ||
1503                       test_bit(R5_InJournal, &dev->flags)))) {
1504                         if (test_bit(R5_InJournal, &dev->flags))
1505                                 srcs[slot] = sh->dev[i].orig_page;
1506                         else
1507                                 srcs[slot] = sh->dev[i].page;
1508                 }
1509                 i = raid6_next_disk(i, disks);
1510         } while (i != d0_idx);
1511
1512         return syndrome_disks;
1513 }
1514
1515 static struct dma_async_tx_descriptor *
1516 ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
1517 {
1518         int disks = sh->disks;
1519         struct page **blocks = to_addr_page(percpu, 0);
1520         int target;
1521         int qd_idx = sh->qd_idx;
1522         struct dma_async_tx_descriptor *tx;
1523         struct async_submit_ctl submit;
1524         struct r5dev *tgt;
1525         struct page *dest;
1526         int i;
1527         int count;
1528
1529         BUG_ON(sh->batch_head);
1530         if (sh->ops.target < 0)
1531                 target = sh->ops.target2;
1532         else if (sh->ops.target2 < 0)
1533                 target = sh->ops.target;
1534         else
1535                 /* we should only have one valid target */
1536                 BUG();
1537         BUG_ON(target < 0);
1538         pr_debug("%s: stripe %llu block: %d\n",
1539                 __func__, (unsigned long long)sh->sector, target);
1540
1541         tgt = &sh->dev[target];
1542         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1543         dest = tgt->page;
1544
1545         atomic_inc(&sh->count);
1546
1547         if (target == qd_idx) {
1548                 count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1549                 blocks[count] = NULL; /* regenerating p is not necessary */
1550                 BUG_ON(blocks[count+1] != dest); /* q should already be set */
1551                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1552                                   ops_complete_compute, sh,
1553                                   to_addr_conv(sh, percpu, 0));
1554                 tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
1555         } else {
1556                 /* Compute any data- or p-drive using XOR */
1557                 count = 0;
1558                 for (i = disks; i-- ; ) {
1559                         if (i == target || i == qd_idx)
1560                                 continue;
1561                         blocks[count++] = sh->dev[i].page;
1562                 }
1563
1564                 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1565                                   NULL, ops_complete_compute, sh,
1566                                   to_addr_conv(sh, percpu, 0));
1567                 tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
1568         }
1569
1570         return tx;
1571 }
1572
1573 static struct dma_async_tx_descriptor *
1574 ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
1575 {
1576         int i, count, disks = sh->disks;
1577         int syndrome_disks = sh->ddf_layout ? disks : disks-2;
1578         int d0_idx = raid6_d0(sh);
1579         int faila = -1, failb = -1;
1580         int target = sh->ops.target;
1581         int target2 = sh->ops.target2;
1582         struct r5dev *tgt = &sh->dev[target];
1583         struct r5dev *tgt2 = &sh->dev[target2];
1584         struct dma_async_tx_descriptor *tx;
1585         struct page **blocks = to_addr_page(percpu, 0);
1586         struct async_submit_ctl submit;
1587
1588         BUG_ON(sh->batch_head);
1589         pr_debug("%s: stripe %llu block1: %d block2: %d\n",
1590                  __func__, (unsigned long long)sh->sector, target, target2);
1591         BUG_ON(target < 0 || target2 < 0);
1592         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1593         BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
1594
1595         /* we need to open-code set_syndrome_sources to handle the
1596          * slot number conversion for 'faila' and 'failb'
1597          */
1598         for (i = 0; i < disks ; i++)
1599                 blocks[i] = NULL;
1600         count = 0;
1601         i = d0_idx;
1602         do {
1603                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1604
1605                 blocks[slot] = sh->dev[i].page;
1606
1607                 if (i == target)
1608                         faila = slot;
1609                 if (i == target2)
1610                         failb = slot;
1611                 i = raid6_next_disk(i, disks);
1612         } while (i != d0_idx);
1613
1614         BUG_ON(faila == failb);
1615         if (failb < faila)
1616                 swap(faila, failb);
1617         pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
1618                  __func__, (unsigned long long)sh->sector, faila, failb);
1619
1620         atomic_inc(&sh->count);
1621
1622         if (failb == syndrome_disks+1) {
1623                 /* Q disk is one of the missing disks */
1624                 if (faila == syndrome_disks) {
1625                         /* Missing P+Q, just recompute */
1626                         init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1627                                           ops_complete_compute, sh,
1628                                           to_addr_conv(sh, percpu, 0));
1629                         return async_gen_syndrome(blocks, 0, syndrome_disks+2,
1630                                                   STRIPE_SIZE, &submit);
1631                 } else {
1632                         struct page *dest;
1633                         int data_target;
1634                         int qd_idx = sh->qd_idx;
1635
1636                         /* Missing D+Q: recompute D from P, then recompute Q */
1637                         if (target == qd_idx)
1638                                 data_target = target2;
1639                         else
1640                                 data_target = target;
1641
1642                         count = 0;
1643                         for (i = disks; i-- ; ) {
1644                                 if (i == data_target || i == qd_idx)
1645                                         continue;
1646                                 blocks[count++] = sh->dev[i].page;
1647                         }
1648                         dest = sh->dev[data_target].page;
1649                         init_async_submit(&submit,
1650                                           ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1651                                           NULL, NULL, NULL,
1652                                           to_addr_conv(sh, percpu, 0));
1653                         tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
1654                                        &submit);
1655
1656                         count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1657                         init_async_submit(&submit, ASYNC_TX_FENCE, tx,
1658                                           ops_complete_compute, sh,
1659                                           to_addr_conv(sh, percpu, 0));
1660                         return async_gen_syndrome(blocks, 0, count+2,
1661                                                   STRIPE_SIZE, &submit);
1662                 }
1663         } else {
1664                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1665                                   ops_complete_compute, sh,
1666                                   to_addr_conv(sh, percpu, 0));
1667                 if (failb == syndrome_disks) {
1668                         /* We're missing D+P. */
1669                         return async_raid6_datap_recov(syndrome_disks+2,
1670                                                        STRIPE_SIZE, faila,
1671                                                        blocks, &submit);
1672                 } else {
1673                         /* We're missing D+D. */
1674                         return async_raid6_2data_recov(syndrome_disks+2,
1675                                                        STRIPE_SIZE, faila, failb,
1676                                                        blocks, &submit);
1677                 }
1678         }
1679 }
1680
1681 static void ops_complete_prexor(void *stripe_head_ref)
1682 {
1683         struct stripe_head *sh = stripe_head_ref;
1684
1685         pr_debug("%s: stripe %llu\n", __func__,
1686                 (unsigned long long)sh->sector);
1687
1688         if (r5c_is_writeback(sh->raid_conf->log))
1689                 /*
1690                  * raid5-cache write back uses orig_page during prexor.
1691                  * After prexor, it is time to free orig_page
1692                  */
1693                 r5c_release_extra_page(sh);
1694 }
1695
1696 static struct dma_async_tx_descriptor *
1697 ops_run_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
1698                 struct dma_async_tx_descriptor *tx)
1699 {
1700         int disks = sh->disks;
1701         struct page **xor_srcs = to_addr_page(percpu, 0);
1702         int count = 0, pd_idx = sh->pd_idx, i;
1703         struct async_submit_ctl submit;
1704
1705         /* existing parity data subtracted */
1706         struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1707
1708         BUG_ON(sh->batch_head);
1709         pr_debug("%s: stripe %llu\n", __func__,
1710                 (unsigned long long)sh->sector);
1711
1712         for (i = disks; i--; ) {
1713                 struct r5dev *dev = &sh->dev[i];
1714                 /* Only process blocks that are known to be uptodate */
1715                 if (test_bit(R5_InJournal, &dev->flags))
1716                         xor_srcs[count++] = dev->orig_page;
1717                 else if (test_bit(R5_Wantdrain, &dev->flags))
1718                         xor_srcs[count++] = dev->page;
1719         }
1720
1721         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1722                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1723         tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1724
1725         return tx;
1726 }
1727
1728 static struct dma_async_tx_descriptor *
1729 ops_run_prexor6(struct stripe_head *sh, struct raid5_percpu *percpu,
1730                 struct dma_async_tx_descriptor *tx)
1731 {
1732         struct page **blocks = to_addr_page(percpu, 0);
1733         int count;
1734         struct async_submit_ctl submit;
1735
1736         pr_debug("%s: stripe %llu\n", __func__,
1737                 (unsigned long long)sh->sector);
1738
1739         count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_WANT_DRAIN);
1740
1741         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_PQ_XOR_DST, tx,
1742                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1743         tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
1744
1745         return tx;
1746 }
1747
1748 static struct dma_async_tx_descriptor *
1749 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1750 {
1751         struct r5conf *conf = sh->raid_conf;
1752         int disks = sh->disks;
1753         int i;
1754         struct stripe_head *head_sh = sh;
1755
1756         pr_debug("%s: stripe %llu\n", __func__,
1757                 (unsigned long long)sh->sector);
1758
1759         for (i = disks; i--; ) {
1760                 struct r5dev *dev;
1761                 struct bio *chosen;
1762
1763                 sh = head_sh;
1764                 if (test_and_clear_bit(R5_Wantdrain, &head_sh->dev[i].flags)) {
1765                         struct bio *wbi;
1766
1767 again:
1768                         dev = &sh->dev[i];
1769                         /*
1770                          * clear R5_InJournal, so when rewriting a page in
1771                          * journal, it is not skipped by r5l_log_stripe()
1772                          */
1773                         clear_bit(R5_InJournal, &dev->flags);
1774                         spin_lock_irq(&sh->stripe_lock);
1775                         chosen = dev->towrite;
1776                         dev->towrite = NULL;
1777                         sh->overwrite_disks = 0;
1778                         BUG_ON(dev->written);
1779                         wbi = dev->written = chosen;
1780                         spin_unlock_irq(&sh->stripe_lock);
1781                         WARN_ON(dev->page != dev->orig_page);
1782
1783                         while (wbi && wbi->bi_iter.bi_sector <
1784                                 dev->sector + STRIPE_SECTORS) {
1785                                 if (wbi->bi_opf & REQ_FUA)
1786                                         set_bit(R5_WantFUA, &dev->flags);
1787                                 if (wbi->bi_opf & REQ_SYNC)
1788                                         set_bit(R5_SyncIO, &dev->flags);
1789                                 if (bio_op(wbi) == REQ_OP_DISCARD)
1790                                         set_bit(R5_Discard, &dev->flags);
1791                                 else {
1792                                         tx = async_copy_data(1, wbi, &dev->page,
1793                                                              dev->sector, tx, sh,
1794                                                              r5c_is_writeback(conf->log));
1795                                         if (dev->page != dev->orig_page &&
1796                                             !r5c_is_writeback(conf->log)) {
1797                                                 set_bit(R5_SkipCopy, &dev->flags);
1798                                                 clear_bit(R5_UPTODATE, &dev->flags);
1799                                                 clear_bit(R5_OVERWRITE, &dev->flags);
1800                                         }
1801                                 }
1802                                 wbi = r5_next_bio(wbi, dev->sector);
1803                         }
1804
1805                         if (head_sh->batch_head) {
1806                                 sh = list_first_entry(&sh->batch_list,
1807                                                       struct stripe_head,
1808                                                       batch_list);
1809                                 if (sh == head_sh)
1810                                         continue;
1811                                 goto again;
1812                         }
1813                 }
1814         }
1815
1816         return tx;
1817 }
1818
1819 static void ops_complete_reconstruct(void *stripe_head_ref)
1820 {
1821         struct stripe_head *sh = stripe_head_ref;
1822         int disks = sh->disks;
1823         int pd_idx = sh->pd_idx;
1824         int qd_idx = sh->qd_idx;
1825         int i;
1826         bool fua = false, sync = false, discard = false;
1827
1828         pr_debug("%s: stripe %llu\n", __func__,
1829                 (unsigned long long)sh->sector);
1830
1831         for (i = disks; i--; ) {
1832                 fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
1833                 sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
1834                 discard |= test_bit(R5_Discard, &sh->dev[i].flags);
1835         }
1836
1837         for (i = disks; i--; ) {
1838                 struct r5dev *dev = &sh->dev[i];
1839
1840                 if (dev->written || i == pd_idx || i == qd_idx) {
1841                         if (!discard && !test_bit(R5_SkipCopy, &dev->flags))
1842                                 set_bit(R5_UPTODATE, &dev->flags);
1843                         if (fua)
1844                                 set_bit(R5_WantFUA, &dev->flags);
1845                         if (sync)
1846                                 set_bit(R5_SyncIO, &dev->flags);
1847                 }
1848         }
1849
1850         if (sh->reconstruct_state == reconstruct_state_drain_run)
1851                 sh->reconstruct_state = reconstruct_state_drain_result;
1852         else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
1853                 sh->reconstruct_state = reconstruct_state_prexor_drain_result;
1854         else {
1855                 BUG_ON(sh->reconstruct_state != reconstruct_state_run);
1856                 sh->reconstruct_state = reconstruct_state_result;
1857         }
1858
1859         set_bit(STRIPE_HANDLE, &sh->state);
1860         raid5_release_stripe(sh);
1861 }
1862
1863 static void
1864 ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
1865                      struct dma_async_tx_descriptor *tx)
1866 {
1867         int disks = sh->disks;
1868         struct page **xor_srcs;
1869         struct async_submit_ctl submit;
1870         int count, pd_idx = sh->pd_idx, i;
1871         struct page *xor_dest;
1872         int prexor = 0;
1873         unsigned long flags;
1874         int j = 0;
1875         struct stripe_head *head_sh = sh;
1876         int last_stripe;
1877
1878         pr_debug("%s: stripe %llu\n", __func__,
1879                 (unsigned long long)sh->sector);
1880
1881         for (i = 0; i < sh->disks; i++) {
1882                 if (pd_idx == i)
1883                         continue;
1884                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
1885                         break;
1886         }
1887         if (i >= sh->disks) {
1888                 atomic_inc(&sh->count);
1889                 set_bit(R5_Discard, &sh->dev[pd_idx].flags);
1890                 ops_complete_reconstruct(sh);
1891                 return;
1892         }
1893 again:
1894         count = 0;
1895         xor_srcs = to_addr_page(percpu, j);
1896         /* check if prexor is active which means only process blocks
1897          * that are part of a read-modify-write (written)
1898          */
1899         if (head_sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1900                 prexor = 1;
1901                 xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1902                 for (i = disks; i--; ) {
1903                         struct r5dev *dev = &sh->dev[i];
1904                         if (head_sh->dev[i].written ||
1905                             test_bit(R5_InJournal, &head_sh->dev[i].flags))
1906                                 xor_srcs[count++] = dev->page;
1907                 }
1908         } else {
1909                 xor_dest = sh->dev[pd_idx].page;
1910                 for (i = disks; i--; ) {
1911                         struct r5dev *dev = &sh->dev[i];
1912                         if (i != pd_idx)
1913                                 xor_srcs[count++] = dev->page;
1914                 }
1915         }
1916
1917         /* 1/ if we prexor'd then the dest is reused as a source
1918          * 2/ if we did not prexor then we are redoing the parity
1919          * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
1920          * for the synchronous xor case
1921          */
1922         last_stripe = !head_sh->batch_head ||
1923                 list_first_entry(&sh->batch_list,
1924                                  struct stripe_head, batch_list) == head_sh;
1925         if (last_stripe) {
1926                 flags = ASYNC_TX_ACK |
1927                         (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
1928
1929                 atomic_inc(&head_sh->count);
1930                 init_async_submit(&submit, flags, tx, ops_complete_reconstruct, head_sh,
1931                                   to_addr_conv(sh, percpu, j));
1932         } else {
1933                 flags = prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST;
1934                 init_async_submit(&submit, flags, tx, NULL, NULL,
1935                                   to_addr_conv(sh, percpu, j));
1936         }
1937
1938         if (unlikely(count == 1))
1939                 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
1940         else
1941                 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1942         if (!last_stripe) {
1943                 j++;
1944                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1945                                       batch_list);
1946                 goto again;
1947         }
1948 }
1949
1950 static void
1951 ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
1952                      struct dma_async_tx_descriptor *tx)
1953 {
1954         struct async_submit_ctl submit;
1955         struct page **blocks;
1956         int count, i, j = 0;
1957         struct stripe_head *head_sh = sh;
1958         int last_stripe;
1959         int synflags;
1960         unsigned long txflags;
1961
1962         pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
1963
1964         for (i = 0; i < sh->disks; i++) {
1965                 if (sh->pd_idx == i || sh->qd_idx == i)
1966                         continue;
1967                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
1968                         break;
1969         }
1970         if (i >= sh->disks) {
1971                 atomic_inc(&sh->count);
1972                 set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
1973                 set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
1974                 ops_complete_reconstruct(sh);
1975                 return;
1976         }
1977
1978 again:
1979         blocks = to_addr_page(percpu, j);
1980
1981         if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1982                 synflags = SYNDROME_SRC_WRITTEN;
1983                 txflags = ASYNC_TX_ACK | ASYNC_TX_PQ_XOR_DST;
1984         } else {
1985                 synflags = SYNDROME_SRC_ALL;
1986                 txflags = ASYNC_TX_ACK;
1987         }
1988
1989         count = set_syndrome_sources(blocks, sh, synflags);
1990         last_stripe = !head_sh->batch_head ||
1991                 list_first_entry(&sh->batch_list,
1992                                  struct stripe_head, batch_list) == head_sh;
1993
1994         if (last_stripe) {
1995                 atomic_inc(&head_sh->count);
1996                 init_async_submit(&submit, txflags, tx, ops_complete_reconstruct,
1997                                   head_sh, to_addr_conv(sh, percpu, j));
1998         } else
1999                 init_async_submit(&submit, 0, tx, NULL, NULL,
2000                                   to_addr_conv(sh, percpu, j));
2001         tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
2002         if (!last_stripe) {
2003                 j++;
2004                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
2005                                       batch_list);
2006                 goto again;
2007         }
2008 }
2009
2010 static void ops_complete_check(void *stripe_head_ref)
2011 {
2012         struct stripe_head *sh = stripe_head_ref;
2013
2014         pr_debug("%s: stripe %llu\n", __func__,
2015                 (unsigned long long)sh->sector);
2016
2017         sh->check_state = check_state_check_result;
2018         set_bit(STRIPE_HANDLE, &sh->state);
2019         raid5_release_stripe(sh);
2020 }
2021
2022 static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
2023 {
2024         int disks = sh->disks;
2025         int pd_idx = sh->pd_idx;
2026         int qd_idx = sh->qd_idx;
2027         struct page *xor_dest;
2028         struct page **xor_srcs = to_addr_page(percpu, 0);
2029         struct dma_async_tx_descriptor *tx;
2030         struct async_submit_ctl submit;
2031         int count;
2032         int i;
2033
2034         pr_debug("%s: stripe %llu\n", __func__,
2035                 (unsigned long long)sh->sector);
2036
2037         BUG_ON(sh->batch_head);
2038         count = 0;
2039         xor_dest = sh->dev[pd_idx].page;
2040         xor_srcs[count++] = xor_dest;
2041         for (i = disks; i--; ) {
2042                 if (i == pd_idx || i == qd_idx)
2043                         continue;
2044                 xor_srcs[count++] = sh->dev[i].page;
2045         }
2046
2047         init_async_submit(&submit, 0, NULL, NULL, NULL,
2048                           to_addr_conv(sh, percpu, 0));
2049         tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
2050                            &sh->ops.zero_sum_result, &submit);
2051
2052         atomic_inc(&sh->count);
2053         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
2054         tx = async_trigger_callback(&submit);
2055 }
2056
2057 static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
2058 {
2059         struct page **srcs = to_addr_page(percpu, 0);
2060         struct async_submit_ctl submit;
2061         int count;
2062
2063         pr_debug("%s: stripe %llu checkp: %d\n", __func__,
2064                 (unsigned long long)sh->sector, checkp);
2065
2066         BUG_ON(sh->batch_head);
2067         count = set_syndrome_sources(srcs, sh, SYNDROME_SRC_ALL);
2068         if (!checkp)
2069                 srcs[count] = NULL;
2070
2071         atomic_inc(&sh->count);
2072         init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
2073                           sh, to_addr_conv(sh, percpu, 0));
2074         async_syndrome_val(srcs, 0, count+2, STRIPE_SIZE,
2075                            &sh->ops.zero_sum_result, percpu->spare_page, &submit);
2076 }
2077
2078 static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
2079 {
2080         int overlap_clear = 0, i, disks = sh->disks;
2081         struct dma_async_tx_descriptor *tx = NULL;
2082         struct r5conf *conf = sh->raid_conf;
2083         int level = conf->level;
2084         struct raid5_percpu *percpu;
2085         unsigned long cpu;
2086
2087         cpu = get_cpu();
2088         percpu = per_cpu_ptr(conf->percpu, cpu);
2089         if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
2090                 ops_run_biofill(sh);
2091                 overlap_clear++;
2092         }
2093
2094         if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
2095                 if (level < 6)
2096                         tx = ops_run_compute5(sh, percpu);
2097                 else {
2098                         if (sh->ops.target2 < 0 || sh->ops.target < 0)
2099                                 tx = ops_run_compute6_1(sh, percpu);
2100                         else
2101                                 tx = ops_run_compute6_2(sh, percpu);
2102                 }
2103                 /* terminate the chain if reconstruct is not set to be run */
2104                 if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
2105                         async_tx_ack(tx);
2106         }
2107
2108         if (test_bit(STRIPE_OP_PARTIAL_PARITY, &ops_request))
2109                 tx = ops_run_partial_parity(sh, percpu, tx);
2110
2111         if (test_bit(STRIPE_OP_PREXOR, &ops_request)) {
2112                 if (level < 6)
2113                         tx = ops_run_prexor5(sh, percpu, tx);
2114                 else
2115                         tx = ops_run_prexor6(sh, percpu, tx);
2116         }
2117
2118         if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
2119                 tx = ops_run_biodrain(sh, tx);
2120                 overlap_clear++;
2121         }
2122
2123         if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
2124                 if (level < 6)
2125                         ops_run_reconstruct5(sh, percpu, tx);
2126                 else
2127                         ops_run_reconstruct6(sh, percpu, tx);
2128         }
2129
2130         if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
2131                 if (sh->check_state == check_state_run)
2132                         ops_run_check_p(sh, percpu);
2133                 else if (sh->check_state == check_state_run_q)
2134                         ops_run_check_pq(sh, percpu, 0);
2135                 else if (sh->check_state == check_state_run_pq)
2136                         ops_run_check_pq(sh, percpu, 1);
2137                 else
2138                         BUG();
2139         }
2140
2141         if (overlap_clear && !sh->batch_head)
2142                 for (i = disks; i--; ) {
2143                         struct r5dev *dev = &sh->dev[i];
2144                         if (test_and_clear_bit(R5_Overlap, &dev->flags))
2145                                 wake_up(&sh->raid_conf->wait_for_overlap);
2146                 }
2147         put_cpu();
2148 }
2149
2150 static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp,
2151         int disks)
2152 {
2153         struct stripe_head *sh;
2154         int i;
2155
2156         sh = kmem_cache_zalloc(sc, gfp);
2157         if (sh) {
2158                 spin_lock_init(&sh->stripe_lock);
2159                 spin_lock_init(&sh->batch_lock);
2160                 INIT_LIST_HEAD(&sh->batch_list);
2161                 INIT_LIST_HEAD(&sh->lru);
2162                 INIT_LIST_HEAD(&sh->r5c);
2163                 INIT_LIST_HEAD(&sh->log_list);
2164                 atomic_set(&sh->count, 1);
2165                 sh->log_start = MaxSector;
2166                 for (i = 0; i < disks; i++) {
2167                         struct r5dev *dev = &sh->dev[i];
2168
2169                         bio_init(&dev->req, &dev->vec, 1);
2170                         bio_init(&dev->rreq, &dev->rvec, 1);
2171                 }
2172         }
2173         return sh;
2174 }
2175 static int grow_one_stripe(struct r5conf *conf, gfp_t gfp)
2176 {
2177         struct stripe_head *sh;
2178
2179         sh = alloc_stripe(conf->slab_cache, gfp, conf->pool_size);
2180         if (!sh)
2181                 return 0;
2182
2183         sh->raid_conf = conf;
2184
2185         if (grow_buffers(sh, gfp)) {
2186                 shrink_buffers(sh);
2187                 kmem_cache_free(conf->slab_cache, sh);
2188                 return 0;
2189         }
2190         sh->hash_lock_index =
2191                 conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS;
2192         /* we just created an active stripe so... */
2193         atomic_inc(&conf->active_stripes);
2194
2195         raid5_release_stripe(sh);
2196         conf->max_nr_stripes++;
2197         return 1;
2198 }
2199
2200 static int grow_stripes(struct r5conf *conf, int num)
2201 {
2202         struct kmem_cache *sc;
2203         int devs = max(conf->raid_disks, conf->previous_raid_disks);
2204
2205         if (conf->mddev->gendisk)
2206                 sprintf(conf->cache_name[0],
2207                         "raid%d-%s", conf->level, mdname(conf->mddev));
2208         else
2209                 sprintf(conf->cache_name[0],
2210                         "raid%d-%p", conf->level, conf->mddev);
2211         sprintf(conf->cache_name[1], "%s-alt", conf->cache_name[0]);
2212
2213         conf->active_name = 0;
2214         sc = kmem_cache_create(conf->cache_name[conf->active_name],
2215                                sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
2216                                0, 0, NULL);
2217         if (!sc)
2218                 return 1;
2219         conf->slab_cache = sc;
2220         conf->pool_size = devs;
2221         while (num--)
2222                 if (!grow_one_stripe(conf, GFP_KERNEL))
2223                         return 1;
2224
2225         return 0;
2226 }
2227
2228 /**
2229  * scribble_len - return the required size of the scribble region
2230  * @num - total number of disks in the array
2231  *
2232  * The size must be enough to contain:
2233  * 1/ a struct page pointer for each device in the array +2
2234  * 2/ room to convert each entry in (1) to its corresponding dma
2235  *    (dma_map_page()) or page (page_address()) address.
2236  *
2237  * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
2238  * calculate over all devices (not just the data blocks), using zeros in place
2239  * of the P and Q blocks.
2240  */
2241 static struct flex_array *scribble_alloc(int num, int cnt, gfp_t flags)
2242 {
2243         struct flex_array *ret;
2244         size_t len;
2245
2246         len = sizeof(struct page *) * (num+2) + sizeof(addr_conv_t) * (num+2);
2247         ret = flex_array_alloc(len, cnt, flags);
2248         if (!ret)
2249                 return NULL;
2250         /* always prealloc all elements, so no locking is required */
2251         if (flex_array_prealloc(ret, 0, cnt, flags)) {
2252                 flex_array_free(ret);
2253                 return NULL;
2254         }
2255         return ret;
2256 }
2257
2258 static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
2259 {
2260         unsigned long cpu;
2261         int err = 0;
2262
2263         /*
2264          * Never shrink. And mddev_suspend() could deadlock if this is called
2265          * from raid5d. In that case, scribble_disks and scribble_sectors
2266          * should equal to new_disks and new_sectors
2267          */
2268         if (conf->scribble_disks >= new_disks &&
2269             conf->scribble_sectors >= new_sectors)
2270                 return 0;
2271         mddev_suspend(conf->mddev);
2272         get_online_cpus();
2273         for_each_present_cpu(cpu) {
2274                 struct raid5_percpu *percpu;
2275                 struct flex_array *scribble;
2276
2277                 percpu = per_cpu_ptr(conf->percpu, cpu);
2278                 scribble = scribble_alloc(new_disks,
2279                                           new_sectors / STRIPE_SECTORS,
2280                                           GFP_NOIO);
2281
2282                 if (scribble) {
2283                         flex_array_free(percpu->scribble);
2284                         percpu->scribble = scribble;
2285                 } else {
2286                         err = -ENOMEM;
2287                         break;
2288                 }
2289         }
2290         put_online_cpus();
2291         mddev_resume(conf->mddev);
2292         if (!err) {
2293                 conf->scribble_disks = new_disks;
2294                 conf->scribble_sectors = new_sectors;
2295         }
2296         return err;
2297 }
2298
2299 static int resize_stripes(struct r5conf *conf, int newsize)
2300 {
2301         /* Make all the stripes able to hold 'newsize' devices.
2302          * New slots in each stripe get 'page' set to a new page.
2303          *
2304          * This happens in stages:
2305          * 1/ create a new kmem_cache and allocate the required number of
2306          *    stripe_heads.
2307          * 2/ gather all the old stripe_heads and transfer the pages across
2308          *    to the new stripe_heads.  This will have the side effect of
2309          *    freezing the array as once all stripe_heads have been collected,
2310          *    no IO will be possible.  Old stripe heads are freed once their
2311          *    pages have been transferred over, and the old kmem_cache is
2312          *    freed when all stripes are done.
2313          * 3/ reallocate conf->disks to be suitable bigger.  If this fails,
2314          *    we simple return a failre status - no need to clean anything up.
2315          * 4/ allocate new pages for the new slots in the new stripe_heads.
2316          *    If this fails, we don't bother trying the shrink the
2317          *    stripe_heads down again, we just leave them as they are.
2318          *    As each stripe_head is processed the new one is released into
2319          *    active service.
2320          *
2321          * Once step2 is started, we cannot afford to wait for a write,
2322          * so we use GFP_NOIO allocations.
2323          */
2324         struct stripe_head *osh, *nsh;
2325         LIST_HEAD(newstripes);
2326         struct disk_info *ndisks;
2327         int err;
2328         struct kmem_cache *sc;
2329         int i;
2330         int hash, cnt;
2331
2332         if (newsize <= conf->pool_size)
2333                 return 0; /* never bother to shrink */
2334
2335         err = md_allow_write(conf->mddev);
2336         if (err)
2337                 return err;
2338
2339         /* Step 1 */
2340         sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
2341                                sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
2342                                0, 0, NULL);
2343         if (!sc)
2344                 return -ENOMEM;
2345
2346         /* Need to ensure auto-resizing doesn't interfere */
2347         mutex_lock(&conf->cache_size_mutex);
2348
2349         for (i = conf->max_nr_stripes; i; i--) {
2350                 nsh = alloc_stripe(sc, GFP_KERNEL, newsize);
2351                 if (!nsh)
2352                         break;
2353
2354                 nsh->raid_conf = conf;
2355                 list_add(&nsh->lru, &newstripes);
2356         }
2357         if (i) {
2358                 /* didn't get enough, give up */
2359                 while (!list_empty(&newstripes)) {
2360                         nsh = list_entry(newstripes.next, struct stripe_head, lru);
2361                         list_del(&nsh->lru);
2362                         kmem_cache_free(sc, nsh);
2363                 }
2364                 kmem_cache_destroy(sc);
2365                 mutex_unlock(&conf->cache_size_mutex);
2366                 return -ENOMEM;
2367         }
2368         /* Step 2 - Must use GFP_NOIO now.
2369          * OK, we have enough stripes, start collecting inactive
2370          * stripes and copying them over
2371          */
2372         hash = 0;
2373         cnt = 0;
2374         list_for_each_entry(nsh, &newstripes, lru) {
2375                 lock_device_hash_lock(conf, hash);
2376                 wait_event_cmd(conf->wait_for_stripe,
2377                                     !list_empty(conf->inactive_list + hash),
2378                                     unlock_device_hash_lock(conf, hash),
2379                                     lock_device_hash_lock(conf, hash));
2380                 osh = get_free_stripe(conf, hash);
2381                 unlock_device_hash_lock(conf, hash);
2382
2383                 for(i=0; i<conf->pool_size; i++) {
2384                         nsh->dev[i].page = osh->dev[i].page;
2385                         nsh->dev[i].orig_page = osh->dev[i].page;
2386                 }
2387                 nsh->hash_lock_index = hash;
2388                 kmem_cache_free(conf->slab_cache, osh);
2389                 cnt++;
2390                 if (cnt >= conf->max_nr_stripes / NR_STRIPE_HASH_LOCKS +
2391                     !!((conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS) > hash)) {
2392                         hash++;
2393                         cnt = 0;
2394                 }
2395         }
2396         kmem_cache_destroy(conf->slab_cache);
2397
2398         /* Step 3.
2399          * At this point, we are holding all the stripes so the array
2400          * is completely stalled, so now is a good time to resize
2401          * conf->disks and the scribble region
2402          */
2403         ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO);
2404         if (ndisks) {
2405                 for (i = 0; i < conf->pool_size; i++)
2406                         ndisks[i] = conf->disks[i];
2407
2408                 for (i = conf->pool_size; i < newsize; i++) {
2409                         ndisks[i].extra_page = alloc_page(GFP_NOIO);
2410                         if (!ndisks[i].extra_page)
2411                                 err = -ENOMEM;
2412                 }
2413
2414                 if (err) {
2415                         for (i = conf->pool_size; i < newsize; i++)
2416                                 if (ndisks[i].extra_page)
2417                                         put_page(ndisks[i].extra_page);
2418                         kfree(ndisks);
2419                 } else {
2420                         kfree(conf->disks);
2421                         conf->disks = ndisks;
2422                 }
2423         } else
2424                 err = -ENOMEM;
2425
2426         mutex_unlock(&conf->cache_size_mutex);
2427         /* Step 4, return new stripes to service */
2428         while(!list_empty(&newstripes)) {
2429                 nsh = list_entry(newstripes.next, struct stripe_head, lru);
2430                 list_del_init(&nsh->lru);
2431
2432                 for (i=conf->raid_disks; i < newsize; i++)
2433                         if (nsh->dev[i].page == NULL) {
2434                                 struct page *p = alloc_page(GFP_NOIO);
2435                                 nsh->dev[i].page = p;
2436                                 nsh->dev[i].orig_page = p;
2437                                 if (!p)
2438                                         err = -ENOMEM;
2439                         }
2440                 raid5_release_stripe(nsh);
2441         }
2442         /* critical section pass, GFP_NOIO no longer needed */
2443
2444         conf->slab_cache = sc;
2445         conf->active_name = 1-conf->active_name;
2446         if (!err)
2447                 conf->pool_size = newsize;
2448         return err;
2449 }
2450
2451 static int drop_one_stripe(struct r5conf *conf)
2452 {
2453         struct stripe_head *sh;
2454         int hash = (conf->max_nr_stripes - 1) & STRIPE_HASH_LOCKS_MASK;
2455
2456         spin_lock_irq(conf->hash_locks + hash);
2457         sh = get_free_stripe(conf, hash);
2458         spin_unlock_irq(conf->hash_locks + hash);
2459         if (!sh)
2460                 return 0;
2461         BUG_ON(atomic_read(&sh->count));
2462         shrink_buffers(sh);
2463         kmem_cache_free(conf->slab_cache, sh);
2464         atomic_dec(&conf->active_stripes);
2465         conf->max_nr_stripes--;
2466         return 1;
2467 }
2468
2469 static void shrink_stripes(struct r5conf *conf)
2470 {
2471         while (conf->max_nr_stripes &&
2472                drop_one_stripe(conf))
2473                 ;
2474
2475         kmem_cache_destroy(conf->slab_cache);
2476         conf->slab_cache = NULL;
2477 }
2478
2479 static void raid5_end_read_request(struct bio * bi)
2480 {
2481         struct stripe_head *sh = bi->bi_private;
2482         struct r5conf *conf = sh->raid_conf;
2483         int disks = sh->disks, i;
2484         char b[BDEVNAME_SIZE];
2485         struct md_rdev *rdev = NULL;
2486         sector_t s;
2487
2488         for (i=0 ; i<disks; i++)
2489                 if (bi == &sh->dev[i].req)
2490                         break;
2491
2492         pr_debug("end_read_request %llu/%d, count: %d, error %d.\n",
2493                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2494                 bi->bi_error);
2495         if (i == disks) {
2496                 bio_reset(bi);
2497                 BUG();
2498                 return;
2499         }
2500         if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2501                 /* If replacement finished while this request was outstanding,
2502                  * 'replacement' might be NULL already.
2503                  * In that case it moved down to 'rdev'.
2504                  * rdev is not removed until all requests are finished.
2505                  */
2506                 rdev = conf->disks[i].replacement;
2507         if (!rdev)
2508                 rdev = conf->disks[i].rdev;
2509
2510         if (use_new_offset(conf, sh))
2511                 s = sh->sector + rdev->new_data_offset;
2512         else
2513                 s = sh->sector + rdev->data_offset;
2514         if (!bi->bi_error) {
2515                 set_bit(R5_UPTODATE, &sh->dev[i].flags);
2516                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2517                         /* Note that this cannot happen on a
2518                          * replacement device.  We just fail those on
2519                          * any error
2520                          */
2521                         pr_info_ratelimited(
2522                                 "md/raid:%s: read error corrected (%lu sectors at %llu on %s)\n",
2523                                 mdname(conf->mddev), STRIPE_SECTORS,
2524                                 (unsigned long long)s,
2525                                 bdevname(rdev->bdev, b));
2526                         atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
2527                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2528                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2529                 } else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2530                         clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2531
2532                 if (test_bit(R5_InJournal, &sh->dev[i].flags))
2533                         /*
2534                          * end read for a page in journal, this
2535                          * must be preparing for prexor in rmw
2536                          */
2537                         set_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags);
2538
2539                 if (atomic_read(&rdev->read_errors))
2540                         atomic_set(&rdev->read_errors, 0);
2541         } else {
2542                 const char *bdn = bdevname(rdev->bdev, b);
2543                 int retry = 0;
2544                 int set_bad = 0;
2545
2546                 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
2547                 atomic_inc(&rdev->read_errors);
2548                 if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2549                         pr_warn_ratelimited(
2550                                 "md/raid:%s: read error on replacement device (sector %llu on %s).\n",
2551                                 mdname(conf->mddev),
2552                                 (unsigned long long)s,
2553                                 bdn);
2554                 else if (conf->mddev->degraded >= conf->max_degraded) {
2555                         set_bad = 1;
2556                         pr_warn_ratelimited(
2557                                 "md/raid:%s: read error not correctable (sector %llu on %s).\n",
2558                                 mdname(conf->mddev),
2559                                 (unsigned long long)s,
2560                                 bdn);
2561                 } else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
2562                         /* Oh, no!!! */
2563                         set_bad = 1;
2564                         pr_warn_ratelimited(
2565                                 "md/raid:%s: read error NOT corrected!! (sector %llu on %s).\n",
2566                                 mdname(conf->mddev),
2567                                 (unsigned long long)s,
2568                                 bdn);
2569                 } else if (atomic_read(&rdev->read_errors)
2570                          > conf->max_nr_stripes)
2571                         pr_warn("md/raid:%s: Too many read errors, failing device %s.\n",
2572                                mdname(conf->mddev), bdn);
2573                 else
2574                         retry = 1;
2575                 if (set_bad && test_bit(In_sync, &rdev->flags)
2576                     && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2577                         retry = 1;
2578                 if (retry)
2579                         if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
2580                                 set_bit(R5_ReadError, &sh->dev[i].flags);
2581                                 clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2582                         } else
2583                                 set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2584                 else {
2585                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2586                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2587                         if (!(set_bad
2588                               && test_bit(In_sync, &rdev->flags)
2589                               && rdev_set_badblocks(
2590                                       rdev, sh->sector, STRIPE_SECTORS, 0)))
2591                                 md_error(conf->mddev, rdev);
2592                 }
2593         }
2594         rdev_dec_pending(rdev, conf->mddev);
2595         bio_reset(bi);
2596         clear_bit(R5_LOCKED, &sh->dev[i].flags);
2597         set_bit(STRIPE_HANDLE, &sh->state);
2598         raid5_release_stripe(sh);
2599 }
2600
2601 static void raid5_end_write_request(struct bio *bi)
2602 {
2603         struct stripe_head *sh = bi->bi_private;
2604         struct r5conf *conf = sh->raid_conf;
2605         int disks = sh->disks, i;
2606         struct md_rdev *uninitialized_var(rdev);
2607         sector_t first_bad;
2608         int bad_sectors;
2609         int replacement = 0;
2610
2611         for (i = 0 ; i < disks; i++) {
2612                 if (bi == &sh->dev[i].req) {
2613                         rdev = conf->disks[i].rdev;
2614                         break;
2615                 }
2616                 if (bi == &sh->dev[i].rreq) {
2617                         rdev = conf->disks[i].replacement;
2618                         if (rdev)
2619                                 replacement = 1;
2620                         else
2621                                 /* rdev was removed and 'replacement'
2622                                  * replaced it.  rdev is not removed
2623                                  * until all requests are finished.
2624                                  */
2625                                 rdev = conf->disks[i].rdev;
2626                         break;
2627                 }
2628         }
2629         pr_debug("end_write_request %llu/%d, count %d, error: %d.\n",
2630                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2631                 bi->bi_error);
2632         if (i == disks) {
2633                 bio_reset(bi);
2634                 BUG();
2635                 return;
2636         }
2637
2638         if (replacement) {
2639                 if (bi->bi_error)
2640                         md_error(conf->mddev, rdev);
2641                 else if (is_badblock(rdev, sh->sector,
2642                                      STRIPE_SECTORS,
2643                                      &first_bad, &bad_sectors))
2644                         set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
2645         } else {
2646                 if (bi->bi_error) {
2647                         set_bit(STRIPE_DEGRADED, &sh->state);
2648                         set_bit(WriteErrorSeen, &rdev->flags);
2649                         set_bit(R5_WriteError, &sh->dev[i].flags);
2650                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
2651                                 set_bit(MD_RECOVERY_NEEDED,
2652                                         &rdev->mddev->recovery);
2653                 } else if (is_badblock(rdev, sh->sector,
2654                                        STRIPE_SECTORS,
2655                                        &first_bad, &bad_sectors)) {
2656                         set_bit(R5_MadeGood, &sh->dev[i].flags);
2657                         if (test_bit(R5_ReadError, &sh->dev[i].flags))
2658                                 /* That was a successful write so make
2659                                  * sure it looks like we already did
2660                                  * a re-write.
2661                                  */
2662                                 set_bit(R5_ReWrite, &sh->dev[i].flags);
2663                 }
2664         }
2665         rdev_dec_pending(rdev, conf->mddev);
2666
2667         if (sh->batch_head && bi->bi_error && !replacement)
2668                 set_bit(STRIPE_BATCH_ERR, &sh->batch_head->state);
2669
2670         bio_reset(bi);
2671         if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
2672                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
2673         set_bit(STRIPE_HANDLE, &sh->state);
2674         raid5_release_stripe(sh);
2675
2676         if (sh->batch_head && sh != sh->batch_head)
2677                 raid5_release_stripe(sh->batch_head);
2678 }
2679
2680 static void raid5_build_block(struct stripe_head *sh, int i, int previous)
2681 {
2682         struct r5dev *dev = &sh->dev[i];
2683
2684         dev->flags = 0;
2685         dev->sector = raid5_compute_blocknr(sh, i, previous);
2686 }
2687
2688 static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
2689 {
2690         char b[BDEVNAME_SIZE];
2691         struct r5conf *conf = mddev->private;
2692         unsigned long flags;
2693         pr_debug("raid456: error called\n");
2694
2695         spin_lock_irqsave(&conf->device_lock, flags);
2696         clear_bit(In_sync, &rdev->flags);
2697         mddev->degraded = raid5_calc_degraded(conf);
2698         spin_unlock_irqrestore(&conf->device_lock, flags);
2699         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2700
2701         set_bit(Blocked, &rdev->flags);
2702         set_bit(Faulty, &rdev->flags);
2703         set_mask_bits(&mddev->sb_flags, 0,
2704                       BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
2705         pr_crit("md/raid:%s: Disk failure on %s, disabling device.\n"
2706                 "md/raid:%s: Operation continuing on %d devices.\n",
2707                 mdname(mddev),
2708                 bdevname(rdev->bdev, b),
2709                 mdname(mddev),
2710                 conf->raid_disks - mddev->degraded);
2711         r5c_update_on_rdev_error(mddev);
2712 }
2713
2714 /*
2715  * Input: a 'big' sector number,
2716  * Output: index of the data and parity disk, and the sector # in them.
2717  */
2718 sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
2719                               int previous, int *dd_idx,
2720                               struct stripe_head *sh)
2721 {
2722         sector_t stripe, stripe2;
2723         sector_t chunk_number;
2724         unsigned int chunk_offset;
2725         int pd_idx, qd_idx;
2726         int ddf_layout = 0;
2727         sector_t new_sector;
2728         int algorithm = previous ? conf->prev_algo
2729                                  : conf->algorithm;
2730         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2731                                          : conf->chunk_sectors;
2732         int raid_disks = previous ? conf->previous_raid_disks
2733                                   : conf->raid_disks;
2734         int data_disks = raid_disks - conf->max_degraded;
2735
2736         /* First compute the information on this sector */
2737
2738         /*
2739          * Compute the chunk number and the sector offset inside the chunk
2740          */
2741         chunk_offset = sector_div(r_sector, sectors_per_chunk);
2742         chunk_number = r_sector;
2743
2744         /*
2745          * Compute the stripe number
2746          */
2747         stripe = chunk_number;
2748         *dd_idx = sector_div(stripe, data_disks);
2749         stripe2 = stripe;
2750         /*
2751          * Select the parity disk based on the user selected algorithm.
2752          */
2753         pd_idx = qd_idx = -1;
2754         switch(conf->level) {
2755         case 4:
2756                 pd_idx = data_disks;
2757                 break;
2758         case 5:
2759                 switch (algorithm) {
2760                 case ALGORITHM_LEFT_ASYMMETRIC:
2761                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
2762                         if (*dd_idx >= pd_idx)
2763                                 (*dd_idx)++;
2764                         break;
2765                 case ALGORITHM_RIGHT_ASYMMETRIC:
2766                         pd_idx = sector_div(stripe2, raid_disks);
2767                         if (*dd_idx >= pd_idx)
2768                                 (*dd_idx)++;
2769                         break;
2770                 case ALGORITHM_LEFT_SYMMETRIC:
2771                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
2772                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2773                         break;
2774                 case ALGORITHM_RIGHT_SYMMETRIC:
2775                         pd_idx = sector_div(stripe2, raid_disks);
2776                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2777                         break;
2778                 case ALGORITHM_PARITY_0:
2779                         pd_idx = 0;
2780                         (*dd_idx)++;
2781                         break;
2782                 case ALGORITHM_PARITY_N:
2783                         pd_idx = data_disks;
2784                         break;
2785                 default:
2786                         BUG();
2787                 }
2788                 break;
2789         case 6:
2790
2791                 switch (algorithm) {
2792                 case ALGORITHM_LEFT_ASYMMETRIC:
2793                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2794                         qd_idx = pd_idx + 1;
2795                         if (pd_idx == raid_disks-1) {
2796                                 (*dd_idx)++;    /* Q D D D P */
2797                                 qd_idx = 0;
2798                         } else if (*dd_idx >= pd_idx)
2799                                 (*dd_idx) += 2; /* D D P Q D */
2800                         break;
2801                 case ALGORITHM_RIGHT_ASYMMETRIC:
2802                         pd_idx = sector_div(stripe2, raid_disks);
2803                         qd_idx = pd_idx + 1;
2804                         if (pd_idx == raid_disks-1) {
2805                                 (*dd_idx)++;    /* Q D D D P */
2806                                 qd_idx = 0;
2807                         } else if (*dd_idx >= pd_idx)
2808                                 (*dd_idx) += 2; /* D D P Q D */
2809                         break;
2810                 case ALGORITHM_LEFT_SYMMETRIC:
2811                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2812                         qd_idx = (pd_idx + 1) % raid_disks;
2813                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2814                         break;
2815                 case ALGORITHM_RIGHT_SYMMETRIC:
2816                         pd_idx = sector_div(stripe2, raid_disks);
2817                         qd_idx = (pd_idx + 1) % raid_disks;
2818                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2819                         break;
2820
2821                 case ALGORITHM_PARITY_0:
2822                         pd_idx = 0;
2823                         qd_idx = 1;
2824                         (*dd_idx) += 2;
2825                         break;
2826                 case ALGORITHM_PARITY_N:
2827                         pd_idx = data_disks;
2828                         qd_idx = data_disks + 1;
2829                         break;
2830
2831                 case ALGORITHM_ROTATING_ZERO_RESTART:
2832                         /* Exactly the same as RIGHT_ASYMMETRIC, but or
2833                          * of blocks for computing Q is different.
2834                          */
2835                         pd_idx = sector_div(stripe2, raid_disks);
2836                         qd_idx = pd_idx + 1;
2837                         if (pd_idx == raid_disks-1) {
2838                                 (*dd_idx)++;    /* Q D D D P */
2839                                 qd_idx = 0;
2840                         } else if (*dd_idx >= pd_idx)
2841                                 (*dd_idx) += 2; /* D D P Q D */
2842                         ddf_layout = 1;
2843                         break;
2844
2845                 case ALGORITHM_ROTATING_N_RESTART:
2846                         /* Same a left_asymmetric, by first stripe is
2847                          * D D D P Q  rather than
2848                          * Q D D D P
2849                          */
2850                         stripe2 += 1;
2851                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2852                         qd_idx = pd_idx + 1;
2853                         if (pd_idx == raid_disks-1) {
2854                                 (*dd_idx)++;    /* Q D D D P */
2855                                 qd_idx = 0;
2856                         } else if (*dd_idx >= pd_idx)
2857                                 (*dd_idx) += 2; /* D D P Q D */
2858                         ddf_layout = 1;
2859                         break;
2860
2861                 case ALGORITHM_ROTATING_N_CONTINUE:
2862                         /* Same as left_symmetric but Q is before P */
2863                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2864                         qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
2865                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2866                         ddf_layout = 1;
2867                         break;
2868
2869                 case ALGORITHM_LEFT_ASYMMETRIC_6:
2870                         /* RAID5 left_asymmetric, with Q on last device */
2871                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2872                         if (*dd_idx >= pd_idx)
2873                                 (*dd_idx)++;
2874                         qd_idx = raid_disks - 1;
2875                         break;
2876
2877                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
2878                         pd_idx = sector_div(stripe2, raid_disks-1);
2879                         if (*dd_idx >= pd_idx)
2880                                 (*dd_idx)++;
2881                         qd_idx = raid_disks - 1;
2882                         break;
2883
2884                 case ALGORITHM_LEFT_SYMMETRIC_6:
2885                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2886                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2887                         qd_idx = raid_disks - 1;
2888                         break;
2889
2890                 case ALGORITHM_RIGHT_SYMMETRIC_6:
2891                         pd_idx = sector_div(stripe2, raid_disks-1);
2892                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2893                         qd_idx = raid_disks - 1;
2894                         break;
2895
2896                 case ALGORITHM_PARITY_0_6:
2897                         pd_idx = 0;
2898                         (*dd_idx)++;
2899                         qd_idx = raid_disks - 1;
2900                         break;
2901
2902                 default:
2903                         BUG();
2904                 }
2905                 break;
2906         }
2907
2908         if (sh) {
2909                 sh->pd_idx = pd_idx;
2910                 sh->qd_idx = qd_idx;
2911                 sh->ddf_layout = ddf_layout;
2912         }
2913         /*
2914          * Finally, compute the new sector number
2915          */
2916         new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
2917         return new_sector;
2918 }
2919
2920 sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous)
2921 {
2922         struct r5conf *conf = sh->raid_conf;
2923         int raid_disks = sh->disks;
2924         int data_disks = raid_disks - conf->max_degraded;
2925         sector_t new_sector = sh->sector, check;
2926         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2927                                          : conf->chunk_sectors;
2928         int algorithm = previous ? conf->prev_algo
2929                                  : conf->algorithm;
2930         sector_t stripe;
2931         int chunk_offset;
2932         sector_t chunk_number;
2933         int dummy1, dd_idx = i;
2934         sector_t r_sector;
2935         struct stripe_head sh2;
2936
2937         chunk_offset = sector_div(new_sector, sectors_per_chunk);
2938         stripe = new_sector;
2939
2940         if (i == sh->pd_idx)
2941                 return 0;
2942         switch(conf->level) {
2943         case 4: break;
2944         case 5:
2945                 switch (algorithm) {
2946                 case ALGORITHM_LEFT_ASYMMETRIC:
2947                 case ALGORITHM_RIGHT_ASYMMETRIC:
2948                         if (i > sh->pd_idx)
2949                                 i--;
2950                         break;
2951                 case ALGORITHM_LEFT_SYMMETRIC:
2952                 case ALGORITHM_RIGHT_SYMMETRIC:
2953                         if (i < sh->pd_idx)
2954                                 i += raid_disks;
2955                         i -= (sh->pd_idx + 1);
2956                         break;
2957                 case ALGORITHM_PARITY_0:
2958                         i -= 1;
2959                         break;
2960                 case ALGORITHM_PARITY_N:
2961                         break;
2962                 default:
2963                         BUG();
2964                 }
2965                 break;
2966         case 6:
2967                 if (i == sh->qd_idx)
2968                         return 0; /* It is the Q disk */
2969                 switch (algorithm) {
2970                 case ALGORITHM_LEFT_ASYMMETRIC:
2971                 case ALGORITHM_RIGHT_ASYMMETRIC:
2972                 case ALGORITHM_ROTATING_ZERO_RESTART:
2973                 case ALGORITHM_ROTATING_N_RESTART:
2974                         if (sh->pd_idx == raid_disks-1)
2975                                 i--;    /* Q D D D P */
2976                         else if (i > sh->pd_idx)
2977                                 i -= 2; /* D D P Q D */
2978                         break;
2979                 case ALGORITHM_LEFT_SYMMETRIC:
2980                 case ALGORITHM_RIGHT_SYMMETRIC:
2981                         if (sh->pd_idx == raid_disks-1)
2982                                 i--; /* Q D D D P */
2983                         else {
2984                                 /* D D P Q D */
2985                                 if (i < sh->pd_idx)
2986                                         i += raid_disks;
2987                                 i -= (sh->pd_idx + 2);
2988                         }
2989                         break;
2990                 case ALGORITHM_PARITY_0:
2991                         i -= 2;
2992                         break;
2993                 case ALGORITHM_PARITY_N:
2994                         break;
2995                 case ALGORITHM_ROTATING_N_CONTINUE:
2996                         /* Like left_symmetric, but P is before Q */
2997                         if (sh->pd_idx == 0)
2998                                 i--;    /* P D D D Q */
2999                         else {
3000                                 /* D D Q P D */
3001                                 if (i < sh->pd_idx)
3002                                         i += raid_disks;
3003                                 i -= (sh->pd_idx + 1);
3004                         }
3005                         break;
3006                 case ALGORITHM_LEFT_ASYMMETRIC_6:
3007                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
3008                         if (i > sh->pd_idx)
3009                                 i--;
3010                         break;
3011                 case ALGORITHM_LEFT_SYMMETRIC_6:
3012                 case ALGORITHM_RIGHT_SYMMETRIC_6:
3013                         if (i < sh->pd_idx)
3014                                 i += data_disks + 1;
3015                         i -= (sh->pd_idx + 1);
3016                         break;
3017                 case ALGORITHM_PARITY_0_6:
3018                         i -= 1;
3019                         break;
3020                 default:
3021                         BUG();
3022                 }
3023                 break;
3024         }
3025
3026         chunk_number = stripe * data_disks + i;
3027         r_sector = chunk_number * sectors_per_chunk + chunk_offset;
3028
3029         check = raid5_compute_sector(conf, r_sector,
3030                                      previous, &dummy1, &sh2);
3031         if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
3032                 || sh2.qd_idx != sh->qd_idx) {
3033                 pr_warn("md/raid:%s: compute_blocknr: map not correct\n",
3034                         mdname(conf->mddev));
3035                 return 0;
3036         }
3037         return r_sector;
3038 }
3039
3040 /*
3041  * There are cases where we want handle_stripe_dirtying() and
3042  * schedule_reconstruction() to delay towrite to some dev of a stripe.
3043  *
3044  * This function checks whether we want to delay the towrite. Specifically,
3045  * we delay the towrite when:
3046  *
3047  *   1. degraded stripe has a non-overwrite to the missing dev, AND this
3048  *      stripe has data in journal (for other devices).
3049  *
3050  *      In this case, when reading data for the non-overwrite dev, it is
3051  *      necessary to handle complex rmw of write back cache (prexor with
3052  *      orig_page, and xor with page). To keep read path simple, we would
3053  *      like to flush data in journal to RAID disks first, so complex rmw
3054  *      is handled in the write patch (handle_stripe_dirtying).
3055  *
3056  *   2. when journal space is critical (R5C_LOG_CRITICAL=1)
3057  *
3058  *      It is important to be able to flush all stripes in raid5-cache.
3059  *      Therefore, we need reserve some space on the journal device for
3060  *      these flushes. If flush operation includes pending writes to the
3061  *      stripe, we need to reserve (conf->raid_disk + 1) pages per stripe
3062  *      for the flush out. If we exclude these pending writes from flush
3063  *      operation, we only need (conf->max_degraded + 1) pages per stripe.
3064  *      Therefore, excluding pending writes in these cases enables more
3065  *      efficient use of the journal device.
3066  *
3067  *      Note: To make sure the stripe makes progress, we only delay
3068  *      towrite for stripes with data already in journal (injournal > 0).
3069  *      When LOG_CRITICAL, stripes with injournal == 0 will be sent to
3070  *      no_space_stripes list.
3071  *
3072  */
3073 static inline bool delay_towrite(struct r5conf *conf,
3074                                  struct r5dev *dev,
3075                                  struct stripe_head_state *s)
3076 {
3077         /* case 1 above */
3078         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3079             !test_bit(R5_Insync, &dev->flags) && s->injournal)
3080                 return true;
3081         /* case 2 above */
3082         if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
3083             s->injournal > 0)
3084                 return true;
3085         return false;
3086 }
3087
3088 static void
3089 schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
3090                          int rcw, int expand)
3091 {
3092         int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx, disks = sh->disks;
3093         struct r5conf *conf = sh->raid_conf;
3094         int level = conf->level;
3095
3096         if (rcw) {
3097                 /*
3098                  * In some cases, handle_stripe_dirtying initially decided to
3099                  * run rmw and allocates extra page for prexor. However, rcw is
3100                  * cheaper later on. We need to free the extra page now,
3101                  * because we won't be able to do that in ops_complete_prexor().
3102                  */
3103                 r5c_release_extra_page(sh);
3104
3105                 for (i = disks; i--; ) {
3106                         struct r5dev *dev = &sh->dev[i];
3107
3108                         if (dev->towrite && !delay_towrite(conf, dev, s)) {
3109                                 set_bit(R5_LOCKED, &dev->flags);
3110                                 set_bit(R5_Wantdrain, &dev->flags);
3111                                 if (!expand)
3112                                         clear_bit(R5_UPTODATE, &dev->flags);
3113                                 s->locked++;
3114                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3115                                 set_bit(R5_LOCKED, &dev->flags);
3116                                 s->locked++;
3117                         }
3118                 }
3119                 /* if we are not expanding this is a proper write request, and
3120                  * there will be bios with new data to be drained into the
3121                  * stripe cache
3122                  */
3123                 if (!expand) {
3124                         if (!s->locked)
3125                                 /* False alarm, nothing to do */
3126                                 return;
3127                         sh->reconstruct_state = reconstruct_state_drain_run;
3128                         set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3129                 } else
3130                         sh->reconstruct_state = reconstruct_state_run;
3131
3132                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3133
3134                 if (s->locked + conf->max_degraded == disks)
3135                         if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
3136                                 atomic_inc(&conf->pending_full_writes);
3137         } else {
3138                 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
3139                         test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
3140                 BUG_ON(level == 6 &&
3141                         (!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
3142                            test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));
3143
3144                 for (i = disks; i--; ) {
3145                         struct r5dev *dev = &sh->dev[i];
3146                         if (i == pd_idx || i == qd_idx)
3147                                 continue;
3148
3149                         if (dev->towrite &&
3150                             (test_bit(R5_UPTODATE, &dev->flags) ||
3151                              test_bit(R5_Wantcompute, &dev->flags))) {
3152                                 set_bit(R5_Wantdrain, &dev->flags);
3153                                 set_bit(R5_LOCKED, &dev->flags);
3154                                 clear_bit(R5_UPTODATE, &dev->flags);
3155                                 s->locked++;
3156                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3157                                 set_bit(R5_LOCKED, &dev->flags);
3158                                 s->locked++;
3159                         }
3160                 }
3161                 if (!s->locked)
3162                         /* False alarm - nothing to do */
3163                         return;
3164                 sh->reconstruct_state = reconstruct_state_prexor_drain_run;
3165                 set_bit(STRIPE_OP_PREXOR, &s->ops_request);
3166                 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3167                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3168         }
3169
3170         /* keep the parity disk(s) locked while asynchronous operations
3171          * are in flight
3172          */
3173         set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
3174         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
3175         s->locked++;
3176
3177         if (level == 6) {
3178                 int qd_idx = sh->qd_idx;
3179                 struct r5dev *dev = &sh->dev[qd_idx];
3180
3181                 set_bit(R5_LOCKED, &dev->flags);
3182                 clear_bit(R5_UPTODATE, &dev->flags);
3183                 s->locked++;
3184         }
3185
3186         if (raid5_has_ppl(sh->raid_conf) &&
3187             test_bit(STRIPE_OP_BIODRAIN, &s->ops_request) &&
3188             !test_bit(STRIPE_FULL_WRITE, &sh->state) &&
3189             test_bit(R5_Insync, &sh->dev[pd_idx].flags))
3190                 set_bit(STRIPE_OP_PARTIAL_PARITY, &s->ops_request);
3191
3192         pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
3193                 __func__, (unsigned long long)sh->sector,
3194                 s->locked, s->ops_request);
3195 }
3196
3197 /*
3198  * Each stripe/dev can have one or more bion attached.
3199  * toread/towrite point to the first in a chain.
3200  * The bi_next chain must be in order.
3201  */
3202 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx,
3203                           int forwrite, int previous)
3204 {
3205         struct bio **bip;
3206         struct r5conf *conf = sh->raid_conf;
3207         int firstwrite=0;
3208
3209         pr_debug("adding bi b#%llu to stripe s#%llu\n",
3210                 (unsigned long long)bi->bi_iter.bi_sector,
3211                 (unsigned long long)sh->sector);
3212
3213         /*
3214          * If several bio share a stripe. The bio bi_phys_segments acts as a
3215          * reference count to avoid race. The reference count should already be
3216          * increased before this function is called (for example, in
3217          * raid5_make_request()), so other bio sharing this stripe will not free the
3218          * stripe. If a stripe is owned by one stripe, the stripe lock will
3219          * protect it.
3220          */
3221         spin_lock_irq(&sh->stripe_lock);
3222         /* Don't allow new IO added to stripes in batch list */
3223         if (sh->batch_head)
3224                 goto overlap;
3225         if (forwrite) {
3226                 bip = &sh->dev[dd_idx].towrite;
3227                 if (*bip == NULL)
3228                         firstwrite = 1;
3229         } else
3230                 bip = &sh->dev[dd_idx].toread;
3231         while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector) {
3232                 if (bio_end_sector(*bip) > bi->bi_iter.bi_sector)
3233                         goto overlap;
3234                 bip = & (*bip)->bi_next;
3235         }
3236         if (*bip && (*bip)->bi_iter.bi_sector < bio_end_sector(bi))
3237                 goto overlap;
3238
3239         if (forwrite && raid5_has_ppl(conf)) {
3240                 /*
3241                  * With PPL only writes to consecutive data chunks within a
3242                  * stripe are allowed because for a single stripe_head we can
3243                  * only have one PPL entry at a time, which describes one data
3244                  * range. Not really an overlap, but wait_for_overlap can be
3245                  * used to handle this.
3246                  */
3247                 sector_t sector;
3248                 sector_t first = 0;
3249                 sector_t last = 0;
3250                 int count = 0;
3251                 int i;
3252
3253                 for (i = 0; i < sh->disks; i++) {
3254                         if (i != sh->pd_idx &&
3255                             (i == dd_idx || sh->dev[i].towrite)) {
3256                                 sector = sh->dev[i].sector;
3257                                 if (count == 0 || sector < first)
3258                                         first = sector;
3259                                 if (sector > last)
3260                                         last = sector;
3261                                 count++;
3262                         }
3263                 }
3264
3265                 if (first + conf->chunk_sectors * (count - 1) != last)
3266                         goto overlap;
3267         }
3268
3269         if (!forwrite || previous)
3270                 clear_bit(STRIPE_BATCH_READY, &sh->state);
3271
3272         BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
3273         if (*bip)
3274                 bi->bi_next = *bip;
3275         *bip = bi;
3276         raid5_inc_bi_active_stripes(bi);
3277
3278         if (forwrite) {
3279                 /* check if page is covered */
3280                 sector_t sector = sh->dev[dd_idx].sector;
3281                 for (bi=sh->dev[dd_idx].towrite;
3282                      sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
3283                              bi && bi->bi_iter.bi_sector <= sector;
3284                      bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
3285                         if (bio_end_sector(bi) >= sector)
3286                                 sector = bio_end_sector(bi);
3287                 }
3288                 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
3289                         if (!test_and_set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags))
3290                                 sh->overwrite_disks++;
3291         }
3292
3293         pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
3294                 (unsigned long long)(*bip)->bi_iter.bi_sector,
3295                 (unsigned long long)sh->sector, dd_idx);
3296
3297         if (conf->mddev->bitmap && firstwrite) {
3298                 /* Cannot hold spinlock over bitmap_startwrite,
3299                  * but must ensure this isn't added to a batch until
3300                  * we have added to the bitmap and set bm_seq.
3301                  * So set STRIPE_BITMAP_PENDING to prevent
3302                  * batching.
3303                  * If multiple add_stripe_bio() calls race here they
3304                  * much all set STRIPE_BITMAP_PENDING.  So only the first one
3305                  * to complete "bitmap_startwrite" gets to set
3306                  * STRIPE_BIT_DELAY.  This is important as once a stripe
3307                  * is added to a batch, STRIPE_BIT_DELAY cannot be changed
3308                  * any more.
3309                  */
3310                 set_bit(STRIPE_BITMAP_PENDING, &sh->state);
3311                 spin_unlock_irq(&sh->stripe_lock);
3312                 bitmap_startwrite(conf->mddev->bitmap, sh->sector,
3313                                   STRIPE_SECTORS, 0);
3314                 spin_lock_irq(&sh->stripe_lock);
3315                 clear_bit(STRIPE_BITMAP_PENDING, &sh->state);
3316                 if (!sh->batch_head) {
3317                         sh->bm_seq = conf->seq_flush+1;
3318                         set_bit(STRIPE_BIT_DELAY, &sh->state);
3319                 }
3320         }
3321         spin_unlock_irq(&sh->stripe_lock);
3322
3323         if (stripe_can_batch(sh))
3324                 stripe_add_to_batch_list(conf, sh);
3325         return 1;
3326
3327  overlap:
3328         set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
3329         spin_unlock_irq(&sh->stripe_lock);
3330         return 0;
3331 }
3332
3333 static void end_reshape(struct r5conf *conf);
3334
3335 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
3336                             struct stripe_head *sh)
3337 {
3338         int sectors_per_chunk =
3339                 previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
3340         int dd_idx;
3341         int chunk_offset = sector_div(stripe, sectors_per_chunk);
3342         int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
3343
3344         raid5_compute_sector(conf,
3345                              stripe * (disks - conf->max_degraded)
3346                              *sectors_per_chunk + chunk_offset,
3347                              previous,
3348                              &dd_idx, sh);
3349 }
3350
3351 static void
3352 handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
3353                                 struct stripe_head_state *s, int disks,
3354                                 struct bio_list *return_bi)
3355 {
3356         int i;
3357         BUG_ON(sh->batch_head);
3358         for (i = disks; i--; ) {
3359                 struct bio *bi;
3360                 int bitmap_end = 0;
3361
3362                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
3363                         struct md_rdev *rdev;
3364                         rcu_read_lock();
3365                         rdev = rcu_dereference(conf->disks[i].rdev);
3366                         if (rdev && test_bit(In_sync, &rdev->flags) &&
3367                             !test_bit(Faulty, &rdev->flags))
3368                                 atomic_inc(&rdev->nr_pending);
3369                         else
3370                                 rdev = NULL;
3371                         rcu_read_unlock();
3372                         if (rdev) {
3373                                 if (!rdev_set_badblocks(
3374                                             rdev,
3375                                             sh->sector,
3376                                             STRIPE_SECTORS, 0))
3377                                         md_error(conf->mddev, rdev);
3378                                 rdev_dec_pending(rdev, conf->mddev);
3379                         }
3380                 }
3381                 spin_lock_irq(&sh->stripe_lock);
3382                 /* fail all writes first */
3383                 bi = sh->dev[i].towrite;
3384                 sh->dev[i].towrite = NULL;
3385                 sh->overwrite_disks = 0;
3386                 spin_unlock_irq(&sh->stripe_lock);
3387                 if (bi)
3388                         bitmap_end = 1;
3389
3390                 log_stripe_write_finished(sh);
3391
3392                 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3393                         wake_up(&conf->wait_for_overlap);
3394
3395                 while (bi && bi->bi_iter.bi_sector <
3396                         sh->dev[i].sector + STRIPE_SECTORS) {
3397                         struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
3398
3399                         bi->bi_error = -EIO;
3400                         if (!raid5_dec_bi_active_stripes(bi)) {
3401                                 md_write_end(conf->mddev);
3402                                 bio_list_add(return_bi, bi);
3403                         }
3404                         bi = nextbi;
3405                 }
3406                 if (bitmap_end)
3407                         bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3408                                 STRIPE_SECTORS, 0, 0);
3409                 bitmap_end = 0;
3410                 /* and fail all 'written' */
3411                 bi = sh->dev[i].written;
3412                 sh->dev[i].written = NULL;
3413                 if (test_and_clear_bit(R5_SkipCopy, &sh->dev[i].flags)) {
3414                         WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
3415                         sh->dev[i].page = sh->dev[i].orig_page;
3416                 }
3417
3418                 if (bi) bitmap_end = 1;
3419                 while (bi && bi->bi_iter.bi_sector <
3420                        sh->dev[i].sector + STRIPE_SECTORS) {
3421                         struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
3422
3423                         bi->bi_error = -EIO;
3424                         if (!raid5_dec_bi_active_stripes(bi)) {
3425                                 md_write_end(conf->mddev);
3426                                 bio_list_add(return_bi, bi);
3427                         }
3428                         bi = bi2;
3429                 }
3430
3431                 /* fail any reads if this device is non-operational and
3432                  * the data has not reached the cache yet.
3433                  */
3434                 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
3435                     s->failed > conf->max_degraded &&
3436                     (!test_bit(R5_Insync, &sh->dev[i].flags) ||
3437                       test_bit(R5_ReadError, &sh->dev[i].flags))) {
3438                         spin_lock_irq(&sh->stripe_lock);
3439                         bi = sh->dev[i].toread;
3440                         sh->dev[i].toread = NULL;
3441                         spin_unlock_irq(&sh->stripe_lock);
3442                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3443                                 wake_up(&conf->wait_for_overlap);
3444                         if (bi)
3445                                 s->to_read--;
3446                         while (bi && bi->bi_iter.bi_sector <
3447                                sh->dev[i].sector + STRIPE_SECTORS) {
3448                                 struct bio *nextbi =
3449                                         r5_next_bio(bi, sh->dev[i].sector);
3450
3451                                 bi->bi_error = -EIO;
3452                                 if (!raid5_dec_bi_active_stripes(bi))
3453                                         bio_list_add(return_bi, bi);
3454                                 bi = nextbi;
3455                         }
3456                 }
3457                 if (bitmap_end)
3458                         bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3459                                         STRIPE_SECTORS, 0, 0);
3460                 /* If we were in the middle of a write the parity block might
3461                  * still be locked - so just clear all R5_LOCKED flags
3462                  */
3463                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
3464         }
3465         s->to_write = 0;
3466         s->written = 0;
3467
3468         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3469                 if (atomic_dec_and_test(&conf->pending_full_writes))
3470                         md_wakeup_thread(conf->mddev->thread);
3471 }
3472
3473 static void
3474 handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
3475                    struct stripe_head_state *s)
3476 {
3477         int abort = 0;
3478         int i;
3479
3480         BUG_ON(sh->batch_head);
3481         clear_bit(STRIPE_SYNCING, &sh->state);
3482         if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
3483                 wake_up(&conf->wait_for_overlap);
3484         s->syncing = 0;
3485         s->replacing = 0;
3486         /* There is nothing more to do for sync/check/repair.
3487          * Don't even need to abort as that is handled elsewhere
3488          * if needed, and not always wanted e.g. if there is a known
3489          * bad block here.
3490          * For recover/replace we need to record a bad block on all
3491          * non-sync devices, or abort the recovery
3492          */
3493         if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
3494                 /* During recovery devices cannot be removed, so
3495                  * locking and refcounting of rdevs is not needed
3496                  */
3497                 rcu_read_lock();
3498                 for (i = 0; i < conf->raid_disks; i++) {
3499                         struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
3500                         if (rdev
3501                             && !test_bit(Faulty, &rdev->flags)
3502                             && !test_bit(In_sync, &rdev->flags)
3503                             && !rdev_set_badblocks(rdev, sh->sector,
3504                                                    STRIPE_SECTORS, 0))
3505                                 abort = 1;
3506                         rdev = rcu_dereference(conf->disks[i].replacement);
3507                         if (rdev
3508                             && !test_bit(Faulty, &rdev->flags)
3509                             && !test_bit(In_sync, &rdev->flags)
3510                             && !rdev_set_badblocks(rdev, sh->sector,
3511                                                    STRIPE_SECTORS, 0))
3512                                 abort = 1;
3513                 }
3514                 rcu_read_unlock();
3515                 if (abort)
3516                         conf->recovery_disabled =
3517                                 conf->mddev->recovery_disabled;
3518         }
3519         md_done_sync(conf->mddev, STRIPE_SECTORS, !abort);
3520 }
3521
3522 static int want_replace(struct stripe_head *sh, int disk_idx)
3523 {
3524         struct md_rdev *rdev;
3525         int rv = 0;
3526
3527         rcu_read_lock();
3528         rdev = rcu_dereference(sh->raid_conf->disks[disk_idx].replacement);
3529         if (rdev
3530             && !test_bit(Faulty, &rdev->flags)
3531             && !test_bit(In_sync, &rdev->flags)
3532             && (rdev->recovery_offset <= sh->sector
3533                 || rdev->mddev->recovery_cp <= sh->sector))
3534                 rv = 1;
3535         rcu_read_unlock();
3536         return rv;
3537 }
3538
3539 static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
3540                            int disk_idx, int disks)
3541 {
3542         struct r5dev *dev = &sh->dev[disk_idx];
3543         struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
3544                                   &sh->dev[s->failed_num[1]] };
3545         int i;
3546
3547
3548         if (test_bit(R5_LOCKED, &dev->flags) ||
3549             test_bit(R5_UPTODATE, &dev->flags))
3550                 /* No point reading this as we already have it or have
3551                  * decided to get it.
3552                  */
3553                 return 0;
3554
3555         if (dev->toread ||
3556             (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)))
3557                 /* We need this block to directly satisfy a request */
3558                 return 1;
3559
3560         if (s->syncing || s->expanding ||
3561             (s->replacing && want_replace(sh, disk_idx)))
3562                 /* When syncing, or expanding we read everything.
3563                  * When replacing, we need the replaced block.
3564                  */
3565                 return 1;
3566
3567         if ((s->failed >= 1 && fdev[0]->toread) ||
3568             (s->failed >= 2 && fdev[1]->toread))
3569                 /* If we want to read from a failed device, then
3570                  * we need to actually read every other device.
3571                  */
3572                 return 1;
3573
3574         /* Sometimes neither read-modify-write nor reconstruct-write
3575          * cycles can work.  In those cases we read every block we
3576          * can.  Then the parity-update is certain to have enough to
3577          * work with.
3578          * This can only be a problem when we need to write something,
3579          * and some device has failed.  If either of those tests
3580          * fail we need look no further.
3581          */
3582         if (!s->failed || !s->to_write)
3583                 return 0;
3584
3585         if (test_bit(R5_Insync, &dev->flags) &&
3586             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3587                 /* Pre-reads at not permitted until after short delay
3588                  * to gather multiple requests.  However if this
3589                  * device is no Insync, the block could only be be computed
3590                  * and there is no need to delay that.
3591                  */
3592                 return 0;
3593
3594         for (i = 0; i < s->failed && i < 2; i++) {
3595                 if (fdev[i]->towrite &&
3596                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3597                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3598                         /* If we have a partial write to a failed
3599                          * device, then we will need to reconstruct
3600                          * the content of that device, so all other
3601                          * devices must be read.
3602                          */
3603                         return 1;
3604         }
3605
3606         /* If we are forced to do a reconstruct-write, either because
3607          * the current RAID6 implementation only supports that, or
3608          * or because parity cannot be trusted and we are currently
3609          * recovering it, there is extra need to be careful.
3610          * If one of the devices that we would need to read, because
3611          * it is not being overwritten (and maybe not written at all)
3612          * is missing/faulty, then we need to read everything we can.
3613          */
3614         if (sh->raid_conf->level != 6 &&
3615             sh->sector < sh->raid_conf->mddev->recovery_cp)
3616                 /* reconstruct-write isn't being forced */
3617                 return 0;
3618         for (i = 0; i < s->failed && i < 2; i++) {
3619                 if (s->failed_num[i] != sh->pd_idx &&
3620                     s->failed_num[i] != sh->qd_idx &&
3621                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3622                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3623                         return 1;
3624         }
3625
3626         return 0;
3627 }
3628
3629 /* fetch_block - checks the given member device to see if its data needs
3630  * to be read or computed to satisfy a request.
3631  *
3632  * Returns 1 when no more member devices need to be checked, otherwise returns
3633  * 0 to tell the loop in handle_stripe_fill to continue
3634  */
3635 static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
3636                        int disk_idx, int disks)
3637 {
3638         struct r5dev *dev = &sh->dev[disk_idx];
3639
3640         /* is the data in this block needed, and can we get it? */
3641         if (need_this_block(sh, s, disk_idx, disks)) {
3642                 /* we would like to get this block, possibly by computing it,
3643                  * otherwise read it if the backing disk is insync
3644                  */
3645                 BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
3646                 BUG_ON(test_bit(R5_Wantread, &dev->flags));
3647                 BUG_ON(sh->batch_head);
3648                 if ((s->uptodate == disks - 1) &&
3649                     (s->failed && (disk_idx == s->failed_num[0] ||
3650                                    disk_idx == s->failed_num[1]))) {
3651                         /* have disk failed, and we're requested to fetch it;
3652                          * do compute it
3653                          */
3654                         pr_debug("Computing stripe %llu block %d\n",
3655                                (unsigned long long)sh->sector, disk_idx);
3656                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3657                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3658                         set_bit(R5_Wantcompute, &dev->flags);
3659                         sh->ops.target = disk_idx;
3660                         sh->ops.target2 = -1; /* no 2nd target */
3661                         s->req_compute = 1;
3662                         /* Careful: from this point on 'uptodate' is in the eye
3663                          * of raid_run_ops which services 'compute' operations
3664                          * before writes. R5_Wantcompute flags a block that will
3665                          * be R5_UPTODATE by the time it is needed for a
3666                          * subsequent operation.
3667                          */
3668                         s->uptodate++;
3669                         return 1;
3670                 } else if (s->uptodate == disks-2 && s->failed >= 2) {
3671                         /* Computing 2-failure is *very* expensive; only
3672                          * do it if failed >= 2
3673                          */
3674                         int other;
3675                         for (other = disks; other--; ) {
3676                                 if (other == disk_idx)
3677                                         continue;
3678                                 if (!test_bit(R5_UPTODATE,
3679                                       &sh->dev[other].flags))
3680                                         break;
3681                         }
3682                         BUG_ON(other < 0);
3683                         pr_debug("Computing stripe %llu blocks %d,%d\n",
3684                                (unsigned long long)sh->sector,
3685                                disk_idx, other);
3686                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3687                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3688                         set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
3689                         set_bit(R5_Wantcompute, &sh->dev[other].flags);
3690                         sh->ops.target = disk_idx;
3691                         sh->ops.target2 = other;
3692                         s->uptodate += 2;
3693                         s->req_compute = 1;
3694                         return 1;
3695                 } else if (test_bit(R5_Insync, &dev->flags)) {
3696                         set_bit(R5_LOCKED, &dev->flags);
3697                         set_bit(R5_Wantread, &dev->flags);
3698                         s->locked++;
3699                         pr_debug("Reading block %d (sync=%d)\n",
3700                                 disk_idx, s->syncing);
3701                 }
3702         }
3703
3704         return 0;
3705 }
3706
3707 /**
3708  * handle_stripe_fill - read or compute data to satisfy pending requests.
3709  */
3710 static void handle_stripe_fill(struct stripe_head *sh,
3711                                struct stripe_head_state *s,
3712                                int disks)
3713 {
3714         int i;
3715
3716         /* look for blocks to read/compute, skip this if a compute
3717          * is already in flight, or if the stripe contents are in the
3718          * midst of changing due to a write
3719          */
3720         if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
3721             !sh->reconstruct_state) {
3722
3723                 /*
3724                  * For degraded stripe with data in journal, do not handle
3725                  * read requests yet, instead, flush the stripe to raid
3726                  * disks first, this avoids handling complex rmw of write
3727                  * back cache (prexor with orig_page, and then xor with
3728                  * page) in the read path
3729                  */
3730                 if (s->injournal && s->failed) {
3731                         if (test_bit(STRIPE_R5C_CACHING, &sh->state))
3732                                 r5c_make_stripe_write_out(sh);
3733                         goto out;
3734                 }
3735
3736                 for (i = disks; i--; )
3737                         if (fetch_block(sh, s, i, disks))
3738                                 break;
3739         }
3740 out:
3741         set_bit(STRIPE_HANDLE, &sh->state);
3742 }
3743
3744 static void break_stripe_batch_list(struct stripe_head *head_sh,
3745                                     unsigned long handle_flags);
3746 /* handle_stripe_clean_event
3747  * any written block on an uptodate or failed drive can be returned.
3748  * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
3749  * never LOCKED, so we don't need to test 'failed' directly.
3750  */
3751 static void handle_stripe_clean_event(struct r5conf *conf,
3752         struct stripe_head *sh, int disks, struct bio_list *return_bi)
3753 {
3754         int i;
3755         struct r5dev *dev;
3756         int discard_pending = 0;
3757         struct stripe_head *head_sh = sh;
3758         bool do_endio = false;
3759
3760         for (i = disks; i--; )
3761                 if (sh->dev[i].written) {
3762                         dev = &sh->dev[i];
3763                         if (!test_bit(R5_LOCKED, &dev->flags) &&
3764                             (test_bit(R5_UPTODATE, &dev->flags) ||
3765                              test_bit(R5_Discard, &dev->flags) ||
3766                              test_bit(R5_SkipCopy, &dev->flags))) {
3767                                 /* We can return any write requests */
3768                                 struct bio *wbi, *wbi2;
3769                                 pr_debug("Return write for disc %d\n", i);
3770                                 if (test_and_clear_bit(R5_Discard, &dev->flags))
3771                                         clear_bit(R5_UPTODATE, &dev->flags);
3772                                 if (test_and_clear_bit(R5_SkipCopy, &dev->flags)) {
3773                                         WARN_ON(test_bit(R5_UPTODATE, &dev->flags));
3774                                 }
3775                                 do_endio = true;
3776
3777 returnbi:
3778                                 dev->page = dev->orig_page;
3779                                 wbi = dev->written;
3780                                 dev->written = NULL;
3781                                 while (wbi && wbi->bi_iter.bi_sector <
3782                                         dev->sector + STRIPE_SECTORS) {
3783                                         wbi2 = r5_next_bio(wbi, dev->sector);
3784                                         if (!raid5_dec_bi_active_stripes(wbi)) {
3785                                                 md_write_end(conf->mddev);
3786                                                 bio_list_add(return_bi, wbi);
3787                                         }
3788                                         wbi = wbi2;
3789                                 }
3790                                 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3791                                                 STRIPE_SECTORS,
3792                                          !test_bit(STRIPE_DEGRADED, &sh->state),
3793                                                 0);
3794                                 if (head_sh->batch_head) {
3795                                         sh = list_first_entry(&sh->batch_list,
3796                                                               struct stripe_head,
3797                                                               batch_list);
3798                                         if (sh != head_sh) {
3799                                                 dev = &sh->dev[i];
3800                                                 goto returnbi;
3801                                         }
3802                                 }
3803                                 sh = head_sh;
3804                                 dev = &sh->dev[i];
3805                         } else if (test_bit(R5_Discard, &dev->flags))
3806                                 discard_pending = 1;
3807                 }
3808
3809         log_stripe_write_finished(sh);
3810
3811         if (!discard_pending &&
3812             test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) {
3813                 int hash;
3814                 clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
3815                 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
3816                 if (sh->qd_idx >= 0) {
3817                         clear_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
3818                         clear_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags);
3819                 }
3820                 /* now that discard is done we can proceed with any sync */
3821                 clear_bit(STRIPE_DISCARD, &sh->state);
3822                 /*
3823                  * SCSI discard will change some bio fields and the stripe has
3824                  * no updated data, so remove it from hash list and the stripe
3825                  * will be reinitialized
3826                  */
3827 unhash:
3828                 hash = sh->hash_lock_index;
3829                 spin_lock_irq(conf->hash_locks + hash);
3830                 remove_hash(sh);
3831                 spin_unlock_irq(conf->hash_locks + hash);
3832                 if (head_sh->batch_head) {
3833                         sh = list_first_entry(&sh->batch_list,
3834                                               struct stripe_head, batch_list);
3835                         if (sh != head_sh)
3836                                         goto unhash;
3837                 }
3838                 sh = head_sh;
3839
3840                 if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
3841                         set_bit(STRIPE_HANDLE, &sh->state);
3842
3843         }
3844
3845         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3846                 if (atomic_dec_and_test(&conf->pending_full_writes))
3847                         md_wakeup_thread(conf->mddev->thread);
3848
3849         if (head_sh->batch_head && do_endio)
3850                 break_stripe_batch_list(head_sh, STRIPE_EXPAND_SYNC_FLAGS);
3851 }
3852
3853 /*
3854  * For RMW in write back cache, we need extra page in prexor to store the
3855  * old data. This page is stored in dev->orig_page.
3856  *
3857  * This function checks whether we have data for prexor. The exact logic
3858  * is:
3859  *       R5_UPTODATE && (!R5_InJournal || R5_OrigPageUPTDODATE)
3860  */
3861 static inline bool uptodate_for_rmw(struct r5dev *dev)
3862 {
3863         return (test_bit(R5_UPTODATE, &dev->flags)) &&
3864                 (!test_bit(R5_InJournal, &dev->flags) ||
3865                  test_bit(R5_OrigPageUPTDODATE, &dev->flags));
3866 }
3867
3868 static int handle_stripe_dirtying(struct r5conf *conf,
3869                                   struct stripe_head *sh,
3870                                   struct stripe_head_state *s,
3871                                   int disks)
3872 {
3873         int rmw = 0, rcw = 0, i;
3874         sector_t recovery_cp = conf->mddev->recovery_cp;
3875
3876         /* Check whether resync is now happening or should start.
3877          * If yes, then the array is dirty (after unclean shutdown or
3878          * initial creation), so parity in some stripes might be inconsistent.
3879          * In this case, we need to always do reconstruct-write, to ensure
3880          * that in case of drive failure or read-error correction, we
3881          * generate correct data from the parity.
3882          */
3883         if (conf->rmw_level == PARITY_DISABLE_RMW ||
3884             (recovery_cp < MaxSector && sh->sector >= recovery_cp &&
3885              s->failed == 0)) {
3886                 /* Calculate the real rcw later - for now make it
3887                  * look like rcw is cheaper
3888                  */
3889                 rcw = 1; rmw = 2;
3890                 pr_debug("force RCW rmw_level=%u, recovery_cp=%llu sh->sector=%llu\n",
3891                          conf->rmw_level, (unsigned long long)recovery_cp,
3892                          (unsigned long long)sh->sector);
3893         } else for (i = disks; i--; ) {
3894                 /* would I have to read this buffer for read_modify_write */
3895                 struct r5dev *dev = &sh->dev[i];
3896                 if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3897                      i == sh->pd_idx || i == sh->qd_idx ||
3898                      test_bit(R5_InJournal, &dev->flags)) &&
3899                     !test_bit(R5_LOCKED, &dev->flags) &&
3900                     !(uptodate_for_rmw(dev) ||
3901                       test_bit(R5_Wantcompute, &dev->flags))) {
3902                         if (test_bit(R5_Insync, &dev->flags))
3903                                 rmw++;
3904                         else
3905                                 rmw += 2*disks;  /* cannot read it */
3906                 }
3907                 /* Would I have to read this buffer for reconstruct_write */
3908                 if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3909                     i != sh->pd_idx && i != sh->qd_idx &&
3910                     !test_bit(R5_LOCKED, &dev->flags) &&
3911                     !(test_bit(R5_UPTODATE, &dev->flags) ||
3912                       test_bit(R5_Wantcompute, &dev->flags))) {
3913                         if (test_bit(R5_Insync, &dev->flags))
3914                                 rcw++;
3915                         else
3916                                 rcw += 2*disks;
3917                 }
3918         }
3919
3920         pr_debug("for sector %llu state 0x%lx, rmw=%d rcw=%d\n",
3921                  (unsigned long long)sh->sector, sh->state, rmw, rcw);
3922         set_bit(STRIPE_HANDLE, &sh->state);
3923         if ((rmw < rcw || (rmw == rcw && conf->rmw_level == PARITY_PREFER_RMW)) && rmw > 0) {
3924                 /* prefer read-modify-write, but need to get some data */
3925                 if (conf->mddev->queue)
3926                         blk_add_trace_msg(conf->mddev->queue,
3927                                           "raid5 rmw %llu %d",
3928                                           (unsigned long long)sh->sector, rmw);
3929                 for (i = disks; i--; ) {
3930                         struct r5dev *dev = &sh->dev[i];
3931                         if (test_bit(R5_InJournal, &dev->flags) &&
3932                             dev->page == dev->orig_page &&
3933                             !test_bit(R5_LOCKED, &sh->dev[sh->pd_idx].flags)) {
3934                                 /* alloc page for prexor */
3935                                 struct page *p = alloc_page(GFP_NOIO);
3936
3937                                 if (p) {
3938                                         dev->orig_page = p;
3939                                         continue;
3940                                 }
3941
3942                                 /*
3943                                  * alloc_page() failed, try use
3944                                  * disk_info->extra_page
3945                                  */
3946                                 if (!test_and_set_bit(R5C_EXTRA_PAGE_IN_USE,
3947                                                       &conf->cache_state)) {
3948                                         r5c_use_extra_page(sh);
3949                                         break;
3950                                 }
3951
3952                                 /* extra_page in use, add to delayed_list */
3953                                 set_bit(STRIPE_DELAYED, &sh->state);
3954                                 s->waiting_extra_page = 1;
3955                                 return -EAGAIN;
3956                         }
3957                 }
3958
3959                 for (i = disks; i--; ) {
3960                         struct r5dev *dev = &sh->dev[i];
3961                         if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3962                              i == sh->pd_idx || i == sh->qd_idx ||
3963                              test_bit(R5_InJournal, &dev->flags)) &&
3964                             !test_bit(R5_LOCKED, &dev->flags) &&
3965                             !(uptodate_for_rmw(dev) ||
3966                               test_bit(R5_Wantcompute, &dev->flags)) &&
3967                             test_bit(R5_Insync, &dev->flags)) {
3968                                 if (test_bit(STRIPE_PREREAD_ACTIVE,
3969                                              &sh->state)) {
3970                                         pr_debug("Read_old block %d for r-m-w\n",
3971                                                  i);
3972                                         set_bit(R5_LOCKED, &dev->flags);
3973                                         set_bit(R5_Wantread, &dev->flags);
3974                                         s->locked++;
3975                                 } else {
3976                                         set_bit(STRIPE_DELAYED, &sh->state);
3977                                         set_bit(STRIPE_HANDLE, &sh->state);
3978                                 }
3979                         }
3980                 }
3981         }
3982         if ((rcw < rmw || (rcw == rmw && conf->rmw_level != PARITY_PREFER_RMW)) && rcw > 0) {
3983                 /* want reconstruct write, but need to get some data */
3984                 int qread =0;
3985                 rcw = 0;
3986                 for (i = disks; i--; ) {
3987                         struct r5dev *dev = &sh->dev[i];
3988                         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3989                             i != sh->pd_idx && i != sh->qd_idx &&
3990                             !test_bit(R5_LOCKED, &dev->flags) &&
3991                             !(test_bit(R5_UPTODATE, &dev->flags) ||
3992                               test_bit(R5_Wantcompute, &dev->flags))) {
3993                                 rcw++;
3994                                 if (test_bit(R5_Insync, &dev->flags) &&
3995                                     test_bit(STRIPE_PREREAD_ACTIVE,
3996                                              &sh->state)) {
3997                                         pr_debug("Read_old block "
3998                                                 "%d for Reconstruct\n", i);
3999                                         set_bit(R5_LOCKED, &dev->flags);
4000                                         set_bit(R5_Wantread, &dev->flags);
4001                                         s->locked++;
4002                                         qread++;
4003                                 } else {
4004                                         set_bit(STRIPE_DELAYED, &sh->state);
4005                                         set_bit(STRIPE_HANDLE, &sh->state);
4006                                 }
4007                         }
4008                 }
4009                 if (rcw && conf->mddev->queue)
4010                         blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
4011                                           (unsigned long long)sh->sector,
4012                                           rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
4013         }
4014
4015         if (rcw > disks && rmw > disks &&
4016             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4017                 set_bit(STRIPE_DELAYED, &sh->state);
4018
4019         /* now if nothing is locked, and if we have enough data,
4020          * we can start a write request
4021          */
4022         /* since handle_stripe can be called at any time we need to handle the
4023          * case where a compute block operation has been submitted and then a
4024          * subsequent call wants to start a write request.  raid_run_ops only
4025          * handles the case where compute block and reconstruct are requested
4026          * simultaneously.  If this is not the case then new writes need to be
4027          * held off until the compute completes.
4028          */
4029         if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
4030             (s->locked == 0 && (rcw == 0 || rmw == 0) &&
4031              !test_bit(STRIPE_BIT_DELAY, &sh->state)))
4032                 schedule_reconstruction(sh, s, rcw == 0, 0);
4033         return 0;
4034 }
4035
4036 static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
4037                                 struct stripe_head_state *s, int disks)
4038 {
4039         struct r5dev *dev = NULL;
4040
4041         BUG_ON(sh->batch_head);
4042         set_bit(STRIPE_HANDLE, &sh->state);
4043
4044         switch (sh->check_state) {
4045         case check_state_idle:
4046                 /* start a new check operation if there are no failures */
4047                 if (s->failed == 0) {
4048                         BUG_ON(s->uptodate != disks);
4049                         sh->check_state = check_state_run;
4050                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4051                         clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4052                         s->uptodate--;
4053                         break;
4054                 }
4055                 dev = &sh->dev[s->failed_num[0]];
4056                 /* fall through */
4057         case check_state_compute_result:
4058                 sh->check_state = check_state_idle;
4059                 if (!dev)
4060                         dev = &sh->dev[sh->pd_idx];
4061
4062                 /* check that a write has not made the stripe insync */
4063                 if (test_bit(STRIPE_INSYNC, &sh->state))
4064                         break;
4065
4066                 /* either failed parity check, or recovery is happening */
4067                 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
4068                 BUG_ON(s->uptodate != disks);
4069
4070                 set_bit(R5_LOCKED, &dev->flags);
4071                 s->locked++;
4072                 set_bit(R5_Wantwrite, &dev->flags);
4073
4074                 clear_bit(STRIPE_DEGRADED, &sh->state);
4075                 set_bit(STRIPE_INSYNC, &sh->state);
4076                 break;
4077         case check_state_run:
4078                 break; /* we will be called again upon completion */
4079         case check_state_check_result:
4080                 sh->check_state = check_state_idle;
4081
4082                 /* if a failure occurred during the check operation, leave
4083                  * STRIPE_INSYNC not set and let the stripe be handled again
4084                  */
4085                 if (s->failed)
4086                         break;
4087
4088                 /* handle a successful check operation, if parity is correct
4089                  * we are done.  Otherwise update the mismatch count and repair
4090                  * parity if !MD_RECOVERY_CHECK
4091                  */
4092                 if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
4093                         /* parity is correct (on disc,
4094                          * not in buffer any more)
4095                          */
4096                         set_bit(STRIPE_INSYNC, &sh->state);
4097                 else {
4098                         atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
4099                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
4100                                 /* don't try to repair!! */
4101                                 set_bit(STRIPE_INSYNC, &sh->state);
4102                         else {
4103                                 sh->check_state = check_state_compute_run;
4104                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4105                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4106                                 set_bit(R5_Wantcompute,
4107                                         &sh->dev[sh->pd_idx].flags);
4108                                 sh->ops.target = sh->pd_idx;
4109                                 sh->ops.target2 = -1;
4110                                 s->uptodate++;
4111                         }
4112                 }
4113                 break;
4114         case check_state_compute_run:
4115                 break;
4116         default:
4117                 pr_err("%s: unknown check_state: %d sector: %llu\n",
4118                        __func__, sh->check_state,
4119                        (unsigned long long) sh->sector);
4120                 BUG();
4121         }
4122 }
4123
4124 static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
4125                                   struct stripe_head_state *s,
4126                                   int disks)
4127 {
4128         int pd_idx = sh->pd_idx;
4129         int qd_idx = sh->qd_idx;
4130         struct r5dev *dev;
4131
4132         BUG_ON(sh->batch_head);
4133         set_bit(STRIPE_HANDLE, &sh->state);
4134
4135         BUG_ON(s->failed > 2);
4136
4137         /* Want to check and possibly repair P and Q.
4138          * However there could be one 'failed' device, in which
4139          * case we can only check one of them, possibly using the
4140          * other to generate missing data
4141          */
4142
4143         switch (sh->check_state) {
4144         case check_state_idle:
4145                 /* start a new check operation if there are < 2 failures */
4146                 if (s->failed == s->q_failed) {
4147                         /* The only possible failed device holds Q, so it
4148                          * makes sense to check P (If anything else were failed,
4149                          * we would have used P to recreate it).
4150                          */
4151                         sh->check_state = check_state_run;
4152                 }
4153                 if (!s->q_failed && s->failed < 2) {
4154                         /* Q is not failed, and we didn't use it to generate
4155                          * anything, so it makes sense to check it
4156                          */
4157                         if (sh->check_state == check_state_run)
4158                                 sh->check_state = check_state_run_pq;
4159                         else
4160                                 sh->check_state = check_state_run_q;
4161                 }
4162
4163                 /* discard potentially stale zero_sum_result */
4164                 sh->ops.zero_sum_result = 0;
4165
4166                 if (sh->check_state == check_state_run) {
4167                         /* async_xor_zero_sum destroys the contents of P */
4168                         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
4169                         s->uptodate--;
4170                 }
4171                 if (sh->check_state >= check_state_run &&
4172                     sh->check_state <= check_state_run_pq) {
4173                         /* async_syndrome_zero_sum preserves P and Q, so
4174                          * no need to mark them !uptodate here
4175                          */
4176                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4177                         break;
4178                 }
4179
4180                 /* we have 2-disk failure */
4181                 BUG_ON(s->failed != 2);
4182                 /* fall through */
4183         case check_state_compute_result:
4184                 sh->check_state = check_state_idle;
4185
4186                 /* check that a write has not made the stripe insync */
4187                 if (test_bit(STRIPE_INSYNC, &sh->state))
4188                         break;
4189
4190                 /* now write out any block on a failed drive,
4191                  * or P or Q if they were recomputed
4192                  */
4193                 BUG_ON(s->uptodate < disks - 1); /* We don't need Q to recover */
4194                 if (s->failed == 2) {
4195                         dev = &sh->dev[s->failed_num[1]];
4196                         s->locked++;
4197                         set_bit(R5_LOCKED, &dev->flags);
4198                         set_bit(R5_Wantwrite, &dev->flags);
4199                 }
4200                 if (s->failed >= 1) {
4201                         dev = &sh->dev[s->failed_num[0]];
4202                         s->locked++;
4203                         set_bit(R5_LOCKED, &dev->flags);
4204                         set_bit(R5_Wantwrite, &dev->flags);
4205                 }
4206                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4207                         dev = &sh->dev[pd_idx];
4208                         s->locked++;
4209                         set_bit(R5_LOCKED, &dev->flags);
4210                         set_bit(R5_Wantwrite, &dev->flags);
4211                 }
4212                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4213                         dev = &sh->dev[qd_idx];
4214                         s->locked++;
4215                         set_bit(R5_LOCKED, &dev->flags);
4216                         set_bit(R5_Wantwrite, &dev->flags);
4217                 }
4218                 clear_bit(STRIPE_DEGRADED, &sh->state);
4219
4220                 set_bit(STRIPE_INSYNC, &sh->state);
4221                 break;
4222         case check_state_run:
4223         case check_state_run_q:
4224         case check_state_run_pq:
4225                 break; /* we will be called again upon completion */
4226         case check_state_check_result:
4227                 sh->check_state = check_state_idle;
4228
4229                 /* handle a successful check operation, if parity is correct
4230                  * we are done.  Otherwise update the mismatch count and repair
4231                  * parity if !MD_RECOVERY_CHECK
4232                  */
4233                 if (sh->ops.zero_sum_result == 0) {
4234                         /* both parities are correct */
4235                         if (!s->failed)
4236                                 set_bit(STRIPE_INSYNC, &sh->state);
4237                         else {
4238                                 /* in contrast to the raid5 case we can validate
4239                                  * parity, but still have a failure to write
4240                                  * back
4241                                  */
4242                                 sh->check_state = check_state_compute_result;
4243                                 /* Returning at this point means that we may go
4244                                  * off and bring p and/or q uptodate again so
4245                                  * we make sure to check zero_sum_result again
4246                                  * to verify if p or q need writeback
4247                                  */
4248                         }
4249                 } else {
4250                         atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
4251                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
4252                                 /* don't try to repair!! */
4253                                 set_bit(STRIPE_INSYNC, &sh->state);
4254                         else {
4255                                 int *target = &sh->ops.target;
4256
4257                                 sh->ops.target = -1;
4258                                 sh->ops.target2 = -1;
4259                                 sh->check_state = check_state_compute_run;
4260                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4261                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4262                                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4263                                         set_bit(R5_Wantcompute,
4264                                                 &sh->dev[pd_idx].flags);
4265                                         *target = pd_idx;
4266                                         target = &sh->ops.target2;
4267                                         s->uptodate++;
4268                                 }
4269                                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4270                                         set_bit(R5_Wantcompute,
4271                                                 &sh->dev[qd_idx].flags);
4272                                         *target = qd_idx;
4273                                         s->uptodate++;
4274                                 }
4275                         }
4276                 }
4277                 break;
4278         case check_state_compute_run:
4279                 break;
4280         default:
4281                 pr_warn("%s: unknown check_state: %d sector: %llu\n",
4282                         __func__, sh->check_state,
4283                         (unsigned long long) sh->sector);
4284                 BUG();
4285         }
4286 }
4287
4288 static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
4289 {
4290         int i;
4291
4292         /* We have read all the blocks in this stripe and now we need to
4293          * copy some of them into a target stripe for expand.
4294          */
4295         struct dma_async_tx_descriptor *tx = NULL;
4296         BUG_ON(sh->batch_head);
4297         clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
4298         for (i = 0; i < sh->disks; i++)
4299                 if (i != sh->pd_idx && i != sh->qd_idx) {
4300                         int dd_idx, j;
4301                         struct stripe_head *sh2;
4302                         struct async_submit_ctl submit;
4303
4304                         sector_t bn = raid5_compute_blocknr(sh, i, 1);
4305                         sector_t s = raid5_compute_sector(conf, bn, 0,
4306                                                           &dd_idx, NULL);
4307                         sh2 = raid5_get_active_stripe(conf, s, 0, 1, 1);
4308                         if (sh2 == NULL)
4309                                 /* so far only the early blocks of this stripe
4310                                  * have been requested.  When later blocks
4311                                  * get requested, we will try again
4312                                  */
4313                                 continue;
4314                         if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
4315                            test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
4316                                 /* must have already done this block */
4317                                 raid5_release_stripe(sh2);
4318                                 continue;
4319                         }
4320
4321                         /* place all the copies on one channel */
4322                         init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
4323                         tx = async_memcpy(sh2->dev[dd_idx].page,
4324                                           sh->dev[i].page, 0, 0, STRIPE_SIZE,
4325                                           &submit);
4326
4327                         set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
4328                         set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
4329                         for (j = 0; j < conf->raid_disks; j++)
4330                                 if (j != sh2->pd_idx &&
4331                                     j != sh2->qd_idx &&
4332                                     !test_bit(R5_Expanded, &sh2->dev[j].flags))
4333                                         break;
4334                         if (j == conf->raid_disks) {
4335                                 set_bit(STRIPE_EXPAND_READY, &sh2->state);
4336                                 set_bit(STRIPE_HANDLE, &sh2->state);
4337                         }
4338                         raid5_release_stripe(sh2);
4339
4340                 }
4341         /* done submitting copies, wait for them to complete */
4342         async_tx_quiesce(&tx);
4343 }
4344
4345 /*
4346  * handle_stripe - do things to a stripe.
4347  *
4348  * We lock the stripe by setting STRIPE_ACTIVE and then examine the
4349  * state of various bits to see what needs to be done.
4350  * Possible results:
4351  *    return some read requests which now have data
4352  *    return some write requests which are safely on storage
4353  *    schedule a read on some buffers
4354  *    schedule a write of some buffers
4355  *    return confirmation of parity correctness
4356  *
4357  */
4358
4359 static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
4360 {
4361         struct r5conf *conf = sh->raid_conf;
4362         int disks = sh->disks;
4363         struct r5dev *dev;
4364         int i;
4365         int do_recovery = 0;
4366
4367         memset(s, 0, sizeof(*s));
4368
4369         s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state) && !sh->batch_head;
4370         s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state) && !sh->batch_head;
4371         s->failed_num[0] = -1;
4372         s->failed_num[1] = -1;
4373         s->log_failed = r5l_log_disk_error(conf);
4374
4375         /* Now to look around and see what can be done */
4376         rcu_read_lock();
4377         for (i=disks; i--; ) {
4378                 struct md_rdev *rdev;
4379                 sector_t first_bad;
4380                 int bad_sectors;
4381                 int is_bad = 0;
4382
4383                 dev = &sh->dev[i];
4384
4385                 pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
4386                          i, dev->flags,
4387                          dev->toread, dev->towrite, dev->written);
4388                 /* maybe we can reply to a read
4389                  *
4390                  * new wantfill requests are only permitted while
4391                  * ops_complete_biofill is guaranteed to be inactive
4392                  */
4393                 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
4394                     !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
4395                         set_bit(R5_Wantfill, &dev->flags);
4396
4397                 /* now count some things */
4398                 if (test_bit(R5_LOCKED, &dev->flags))
4399                         s->locked++;
4400                 if (test_bit(R5_UPTODATE, &dev->flags))
4401                         s->uptodate++;
4402                 if (test_bit(R5_Wantcompute, &dev->flags)) {
4403                         s->compute++;
4404                         BUG_ON(s->compute > 2);
4405                 }
4406
4407                 if (test_bit(R5_Wantfill, &dev->flags))
4408                         s->to_fill++;
4409                 else if (dev->toread)
4410                         s->to_read++;
4411                 if (dev->towrite) {
4412                         s->to_write++;
4413                         if (!test_bit(R5_OVERWRITE, &dev->flags))
4414                                 s->non_overwrite++;
4415                 }
4416                 if (dev->written)
4417                         s->written++;
4418                 /* Prefer to use the replacement for reads, but only
4419                  * if it is recovered enough and has no bad blocks.
4420                  */
4421                 rdev = rcu_dereference(conf->disks[i].replacement);
4422                 if (rdev && !test_bit(Faulty, &rdev->flags) &&
4423                     rdev->recovery_offset >= sh->sector + STRIPE_SECTORS &&
4424                     !is_badblock(rdev, sh->sector, STRIPE_SECTORS,
4425                                  &first_bad, &bad_sectors))
4426                         set_bit(R5_ReadRepl, &dev->flags);
4427                 else {
4428                         if (rdev && !test_bit(Faulty, &rdev->flags))
4429                                 set_bit(R5_NeedReplace, &dev->flags);
4430                         else
4431                                 clear_bit(R5_NeedReplace, &dev->flags);
4432                         rdev = rcu_dereference(conf->disks[i].rdev);
4433                         clear_bit(R5_ReadRepl, &dev->flags);
4434                 }
4435                 if (rdev && test_bit(Faulty, &rdev->flags))
4436                         rdev = NULL;
4437                 if (rdev) {
4438                         is_bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
4439                                              &first_bad, &bad_sectors);
4440                         if (s->blocked_rdev == NULL
4441                             && (test_bit(Blocked, &rdev->flags)
4442                                 || is_bad < 0)) {
4443                                 if (is_bad < 0)
4444                                         set_bit(BlockedBadBlocks,
4445                                                 &rdev->flags);
4446                                 s->blocked_rdev = rdev;
4447                                 atomic_inc(&rdev->nr_pending);
4448                         }
4449                 }
4450                 clear_bit(R5_Insync, &dev->flags);
4451                 if (!rdev)
4452                         /* Not in-sync */;
4453                 else if (is_bad) {
4454                         /* also not in-sync */
4455                         if (!test_bit(WriteErrorSeen, &rdev->flags) &&
4456                             test_bit(R5_UPTODATE, &dev->flags)) {
4457                                 /* treat as in-sync, but with a read error
4458                                  * which we can now try to correct
4459                                  */
4460                                 set_bit(R5_Insync, &dev->flags);
4461                                 set_bit(R5_ReadError, &dev->flags);
4462                         }
4463                 } else if (test_bit(In_sync, &rdev->flags))
4464                         set_bit(R5_Insync, &dev->flags);
4465                 else if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
4466                         /* in sync if before recovery_offset */
4467                         set_bit(R5_Insync, &dev->flags);
4468                 else if (test_bit(R5_UPTODATE, &dev->flags) &&
4469                          test_bit(R5_Expanded, &dev->flags))
4470                         /* If we've reshaped into here, we assume it is Insync.
4471                          * We will shortly update recovery_offset to make
4472                          * it official.
4473                          */
4474                         set_bit(R5_Insync, &dev->flags);
4475
4476                 if (test_bit(R5_WriteError, &dev->flags)) {
4477                         /* This flag does not apply to '.replacement'
4478                          * only to .rdev, so make sure to check that*/
4479                         struct md_rdev *rdev2 = rcu_dereference(
4480                                 conf->disks[i].rdev);
4481                         if (rdev2 == rdev)
4482                                 clear_bit(R5_Insync, &dev->flags);
4483                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4484                                 s->handle_bad_blocks = 1;
4485                                 atomic_inc(&rdev2->nr_pending);
4486                         } else
4487                                 clear_bit(R5_WriteError, &dev->flags);
4488                 }
4489                 if (test_bit(R5_MadeGood, &dev->flags)) {
4490                         /* This flag does not apply to '.replacement'
4491                          * only to .rdev, so make sure to check that*/
4492                         struct md_rdev *rdev2 = rcu_dereference(
4493                                 conf->disks[i].rdev);
4494                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4495                                 s->handle_bad_blocks = 1;
4496                                 atomic_inc(&rdev2->nr_pending);
4497                         } else
4498                                 clear_bit(R5_MadeGood, &dev->flags);
4499                 }
4500                 if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
4501                         struct md_rdev *rdev2 = rcu_dereference(
4502                                 conf->disks[i].replacement);
4503                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4504                                 s->handle_bad_blocks = 1;
4505                                 atomic_inc(&rdev2->nr_pending);
4506                         } else
4507                                 clear_bit(R5_MadeGoodRepl, &dev->flags);
4508                 }
4509                 if (!test_bit(R5_Insync, &dev->flags)) {
4510                         /* The ReadError flag will just be confusing now */
4511                         clear_bit(R5_ReadError, &dev->flags);
4512                         clear_bit(R5_ReWrite, &dev->flags);
4513                 }
4514                 if (test_bit(R5_ReadError, &dev->flags))
4515                         clear_bit(R5_Insync, &dev->flags);
4516                 if (!test_bit(R5_Insync, &dev->flags)) {
4517                         if (s->failed < 2)
4518                                 s->failed_num[s->failed] = i;
4519                         s->failed++;
4520                         if (rdev && !test_bit(Faulty, &rdev->flags))
4521                                 do_recovery = 1;
4522                 }
4523
4524                 if (test_bit(R5_InJournal, &dev->flags))
4525                         s->injournal++;
4526                 if (test_bit(R5_InJournal, &dev->flags) && dev->written)
4527                         s->just_cached++;
4528         }
4529         if (test_bit(STRIPE_SYNCING, &sh->state)) {
4530                 /* If there is a failed device being replaced,
4531                  *     we must be recovering.
4532                  * else if we are after recovery_cp, we must be syncing
4533                  * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
4534                  * else we can only be replacing
4535                  * sync and recovery both need to read all devices, and so
4536                  * use the same flag.
4537                  */
4538                 if (do_recovery ||
4539                     sh->sector >= conf->mddev->recovery_cp ||
4540                     test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
4541                         s->syncing = 1;
4542                 else
4543                         s->replacing = 1;
4544         }
4545         rcu_read_unlock();
4546 }
4547
4548 static int clear_batch_ready(struct stripe_head *sh)
4549 {
4550         /* Return '1' if this is a member of batch, or
4551          * '0' if it is a lone stripe or a head which can now be
4552          * handled.
4553          */
4554         struct stripe_head *tmp;
4555         if (!test_and_clear_bit(STRIPE_BATCH_READY, &sh->state))
4556                 return (sh->batch_head && sh->batch_head != sh);
4557         spin_lock(&sh->stripe_lock);
4558         if (!sh->batch_head) {
4559                 spin_unlock(&sh->stripe_lock);
4560                 return 0;
4561         }
4562
4563         /*
4564          * this stripe could be added to a batch list before we check
4565          * BATCH_READY, skips it
4566          */
4567         if (sh->batch_head != sh) {
4568                 spin_unlock(&sh->stripe_lock);
4569                 return 1;
4570         }
4571         spin_lock(&sh->batch_lock);
4572         list_for_each_entry(tmp, &sh->batch_list, batch_list)
4573                 clear_bit(STRIPE_BATCH_READY, &tmp->state);
4574         spin_unlock(&sh->batch_lock);
4575         spin_unlock(&sh->stripe_lock);
4576
4577         /*
4578          * BATCH_READY is cleared, no new stripes can be added.
4579          * batch_list can be accessed without lock
4580          */
4581         return 0;
4582 }
4583
4584 static void break_stripe_batch_list(struct stripe_head *head_sh,
4585                                     unsigned long handle_flags)
4586 {
4587         struct stripe_head *sh, *next;
4588         int i;
4589         int do_wakeup = 0;
4590
4591         list_for_each_entry_safe(sh, next, &head_sh->batch_list, batch_list) {
4592
4593                 list_del_init(&sh->batch_list);
4594
4595                 WARN_ONCE(sh->state & ((1 << STRIPE_ACTIVE) |
4596                                           (1 << STRIPE_SYNCING) |
4597                                           (1 << STRIPE_REPLACED) |
4598                                           (1 << STRIPE_DELAYED) |
4599                                           (1 << STRIPE_BIT_DELAY) |
4600                                           (1 << STRIPE_FULL_WRITE) |
4601                                           (1 << STRIPE_BIOFILL_RUN) |
4602                                           (1 << STRIPE_COMPUTE_RUN)  |
4603                                           (1 << STRIPE_OPS_REQ_PENDING) |
4604                                           (1 << STRIPE_DISCARD) |
4605                                           (1 << STRIPE_BATCH_READY) |
4606                                           (1 << STRIPE_BATCH_ERR) |
4607                                           (1 << STRIPE_BITMAP_PENDING)),
4608                         "stripe state: %lx\n", sh->state);
4609                 WARN_ONCE(head_sh->state & ((1 << STRIPE_DISCARD) |
4610                                               (1 << STRIPE_REPLACED)),
4611                         "head stripe state: %lx\n", head_sh->state);
4612
4613                 set_mask_bits(&sh->state, ~(STRIPE_EXPAND_SYNC_FLAGS |
4614                                             (1 << STRIPE_PREREAD_ACTIVE) |
4615                                             (1 << STRIPE_DEGRADED)),
4616                               head_sh->state & (1 << STRIPE_INSYNC));
4617
4618                 sh->check_state = head_sh->check_state;
4619                 sh->reconstruct_state = head_sh->reconstruct_state;
4620                 for (i = 0; i < sh->disks; i++) {
4621                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
4622                                 do_wakeup = 1;
4623                         sh->dev[i].flags = head_sh->dev[i].flags &
4624                                 (~((1 << R5_WriteError) | (1 << R5_Overlap)));
4625                 }
4626                 spin_lock_irq(&sh->stripe_lock);
4627                 sh->batch_head = NULL;
4628                 spin_unlock_irq(&sh->stripe_lock);
4629                 if (handle_flags == 0 ||
4630                     sh->state & handle_flags)
4631                         set_bit(STRIPE_HANDLE, &sh->state);
4632                 raid5_release_stripe(sh);
4633         }
4634         spin_lock_irq(&head_sh->stripe_lock);
4635         head_sh->batch_head = NULL;
4636         spin_unlock_irq(&head_sh->stripe_lock);
4637         for (i = 0; i < head_sh->disks; i++)
4638                 if (test_and_clear_bit(R5_Overlap, &head_sh->dev[i].flags))
4639                         do_wakeup = 1;
4640         if (head_sh->state & handle_flags)
4641                 set_bit(STRIPE_HANDLE, &head_sh->state);
4642
4643         if (do_wakeup)
4644                 wake_up(&head_sh->raid_conf->wait_for_overlap);
4645 }
4646
4647 static void handle_stripe(struct stripe_head *sh)
4648 {
4649         struct stripe_head_state s;
4650         struct r5conf *conf = sh->raid_conf;
4651         int i;
4652         int prexor;
4653         int disks = sh->disks;
4654         struct r5dev *pdev, *qdev;
4655
4656         clear_bit(STRIPE_HANDLE, &sh->state);
4657         if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
4658                 /* already being handled, ensure it gets handled
4659                  * again when current action finishes */
4660                 set_bit(STRIPE_HANDLE, &sh->state);
4661                 return;
4662         }
4663
4664         if (clear_batch_ready(sh) ) {
4665                 clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
4666                 return;
4667         }
4668
4669         if (test_and_clear_bit(STRIPE_BATCH_ERR, &sh->state))
4670                 break_stripe_batch_list(sh, 0);
4671
4672         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) && !sh->batch_head) {
4673                 spin_lock(&sh->stripe_lock);
4674                 /* Cannot process 'sync' concurrently with 'discard' */
4675                 if (!test_bit(STRIPE_DISCARD, &sh->state) &&
4676                     test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
4677                         set_bit(STRIPE_SYNCING, &sh->state);
4678                         clear_bit(STRIPE_INSYNC, &sh->state);
4679                         clear_bit(STRIPE_REPLACED, &sh->state);
4680                 }
4681                 spin_unlock(&sh->stripe_lock);
4682         }
4683         clear_bit(STRIPE_DELAYED, &sh->state);
4684
4685         pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
4686                 "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
4687                (unsigned long long)sh->sector, sh->state,
4688                atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
4689                sh->check_state, sh->reconstruct_state);
4690
4691         analyse_stripe(sh, &s);
4692
4693         if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
4694                 goto finish;
4695
4696         if (s.handle_bad_blocks) {
4697                 set_bit(STRIPE_HANDLE, &sh->state);
4698                 goto finish;
4699         }
4700
4701         if (unlikely(s.blocked_rdev)) {
4702                 if (s.syncing || s.expanding || s.expanded ||
4703                     s.replacing || s.to_write || s.written) {
4704                         set_bit(STRIPE_HANDLE, &sh->state);
4705                         goto finish;
4706                 }
4707                 /* There is nothing for the blocked_rdev to block */
4708                 rdev_dec_pending(s.blocked_rdev, conf->mddev);
4709                 s.blocked_rdev = NULL;
4710         }
4711
4712         if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
4713                 set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
4714                 set_bit(STRIPE_BIOFILL_RUN, &sh->state);
4715         }
4716
4717         pr_debug("locked=%d uptodate=%d to_read=%d"
4718                " to_write=%d failed=%d failed_num=%d,%d\n",
4719                s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
4720                s.failed_num[0], s.failed_num[1]);
4721         /* check if the array has lost more than max_degraded devices and,
4722          * if so, some requests might need to be failed.
4723          */
4724         if (s.failed > conf->max_degraded || s.log_failed) {
4725                 sh->check_state = 0;
4726                 sh->reconstruct_state = 0;
4727                 break_stripe_batch_list(sh, 0);
4728                 if (s.to_read+s.to_write+s.written)
4729                         handle_failed_stripe(conf, sh, &s, disks, &s.return_bi);
4730                 if (s.syncing + s.replacing)
4731                         handle_failed_sync(conf, sh, &s);
4732         }
4733
4734         /* Now we check to see if any write operations have recently
4735          * completed
4736          */
4737         prexor = 0;
4738         if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
4739                 prexor = 1;
4740         if (sh->reconstruct_state == reconstruct_state_drain_result ||
4741             sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
4742                 sh->reconstruct_state = reconstruct_state_idle;
4743
4744                 /* All the 'written' buffers and the parity block are ready to
4745                  * be written back to disk
4746                  */
4747                 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
4748                        !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
4749                 BUG_ON(sh->qd_idx >= 0 &&
4750                        !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
4751                        !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
4752                 for (i = disks; i--; ) {
4753                         struct r5dev *dev = &sh->dev[i];
4754                         if (test_bit(R5_LOCKED, &dev->flags) &&
4755                                 (i == sh->pd_idx || i == sh->qd_idx ||
4756                                  dev->written || test_bit(R5_InJournal,
4757                                                           &dev->flags))) {
4758                                 pr_debug("Writing block %d\n", i);
4759                                 set_bit(R5_Wantwrite, &dev->flags);
4760                                 if (prexor)
4761                                         continue;
4762                                 if (s.failed > 1)
4763                                         continue;
4764                                 if (!test_bit(R5_Insync, &dev->flags) ||
4765                                     ((i == sh->pd_idx || i == sh->qd_idx)  &&
4766                                      s.failed == 0))
4767                                         set_bit(STRIPE_INSYNC, &sh->state);
4768                         }
4769                 }
4770                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4771                         s.dec_preread_active = 1;
4772         }
4773
4774         /*
4775          * might be able to return some write requests if the parity blocks
4776          * are safe, or on a failed drive
4777          */
4778         pdev = &sh->dev[sh->pd_idx];
4779         s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
4780                 || (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
4781         qdev = &sh->dev[sh->qd_idx];
4782         s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
4783                 || (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
4784                 || conf->level < 6;
4785
4786         if (s.written &&
4787             (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
4788                              && !test_bit(R5_LOCKED, &pdev->flags)
4789                              && (test_bit(R5_UPTODATE, &pdev->flags) ||
4790                                  test_bit(R5_Discard, &pdev->flags))))) &&
4791             (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
4792                              && !test_bit(R5_LOCKED, &qdev->flags)
4793                              && (test_bit(R5_UPTODATE, &qdev->flags) ||
4794                                  test_bit(R5_Discard, &qdev->flags))))))
4795                 handle_stripe_clean_event(conf, sh, disks, &s.return_bi);
4796
4797         if (s.just_cached)
4798                 r5c_handle_cached_data_endio(conf, sh, disks, &s.return_bi);
4799         log_stripe_write_finished(sh);
4800
4801         /* Now we might consider reading some blocks, either to check/generate
4802          * parity, or to satisfy requests
4803          * or to load a block that is being partially written.
4804          */
4805         if (s.to_read || s.non_overwrite
4806             || (conf->level == 6 && s.to_write && s.failed)
4807             || (s.syncing && (s.uptodate + s.compute < disks))
4808             || s.replacing
4809             || s.expanding)
4810                 handle_stripe_fill(sh, &s, disks);
4811
4812         /*
4813          * When the stripe finishes full journal write cycle (write to journal
4814          * and raid disk), this is the clean up procedure so it is ready for
4815          * next operation.
4816          */
4817         r5c_finish_stripe_write_out(conf, sh, &s);
4818
4819         /*
4820          * Now to consider new write requests, cache write back and what else,
4821          * if anything should be read.  We do not handle new writes when:
4822          * 1/ A 'write' operation (copy+xor) is already in flight.
4823          * 2/ A 'check' operation is in flight, as it may clobber the parity
4824          *    block.
4825          * 3/ A r5c cache log write is in flight.
4826          */
4827
4828         if (!sh->reconstruct_state && !sh->check_state && !sh->log_io) {
4829                 if (!r5c_is_writeback(conf->log)) {
4830                         if (s.to_write)
4831                                 handle_stripe_dirtying(conf, sh, &s, disks);
4832                 } else { /* write back cache */
4833                         int ret = 0;
4834
4835                         /* First, try handle writes in caching phase */
4836                         if (s.to_write)
4837                                 ret = r5c_try_caching_write(conf, sh, &s,
4838                                                             disks);
4839                         /*
4840                          * If caching phase failed: ret == -EAGAIN
4841                          *    OR
4842                          * stripe under reclaim: !caching && injournal
4843                          *
4844                          * fall back to handle_stripe_dirtying()
4845                          */
4846                         if (ret == -EAGAIN ||
4847                             /* stripe under reclaim: !caching && injournal */
4848                             (!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
4849                              s.injournal > 0)) {
4850                                 ret = handle_stripe_dirtying(conf, sh, &s,
4851                                                              disks);
4852                                 if (ret == -EAGAIN)
4853                                         goto finish;
4854                         }
4855                 }
4856         }
4857
4858         /* maybe we need to check and possibly fix the parity for this stripe
4859          * Any reads will already have been scheduled, so we just see if enough
4860          * data is available.  The parity check is held off while parity
4861          * dependent operations are in flight.
4862          */
4863         if (sh->check_state ||
4864             (s.syncing && s.locked == 0 &&
4865              !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4866              !test_bit(STRIPE_INSYNC, &sh->state))) {
4867                 if (conf->level == 6)
4868                         handle_parity_checks6(conf, sh, &s, disks);
4869                 else
4870                         handle_parity_checks5(conf, sh, &s, disks);
4871         }
4872
4873         if ((s.replacing || s.syncing) && s.locked == 0
4874             && !test_bit(STRIPE_COMPUTE_RUN, &sh->state)
4875             && !test_bit(STRIPE_REPLACED, &sh->state)) {
4876                 /* Write out to replacement devices where possible */
4877                 for (i = 0; i < conf->raid_disks; i++)
4878                         if (test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
4879                                 WARN_ON(!test_bit(R5_UPTODATE, &sh->dev[i].flags));
4880                                 set_bit(R5_WantReplace, &sh->dev[i].flags);
4881                                 set_bit(R5_LOCKED, &sh->dev[i].flags);
4882                                 s.locked++;
4883                         }
4884                 if (s.replacing)
4885                         set_bit(STRIPE_INSYNC, &sh->state);
4886                 set_bit(STRIPE_REPLACED, &sh->state);
4887         }
4888         if ((s.syncing || s.replacing) && s.locked == 0 &&
4889             !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4890             test_bit(STRIPE_INSYNC, &sh->state)) {
4891                 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
4892                 clear_bit(STRIPE_SYNCING, &sh->state);
4893                 if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
4894                         wake_up(&conf->wait_for_overlap);
4895         }
4896
4897         /* If the failed drives are just a ReadError, then we might need
4898          * to progress the repair/check process
4899          */
4900         if (s.failed <= conf->max_degraded && !conf->mddev->ro)
4901                 for (i = 0; i < s.failed; i++) {
4902                         struct r5dev *dev = &sh->dev[s.failed_num[i]];
4903                         if (test_bit(R5_ReadError, &dev->flags)
4904                             && !test_bit(R5_LOCKED, &dev->flags)
4905                             && test_bit(R5_UPTODATE, &dev->flags)
4906                                 ) {
4907                                 if (!test_bit(R5_ReWrite, &dev->flags)) {
4908                                         set_bit(R5_Wantwrite, &dev->flags);
4909                                         set_bit(R5_ReWrite, &dev->flags);
4910                                         set_bit(R5_LOCKED, &dev->flags);
4911                                         s.locked++;
4912                                 } else {
4913                                         /* let's read it back */
4914                                         set_bit(R5_Wantread, &dev->flags);
4915                                         set_bit(R5_LOCKED, &dev->flags);
4916                                         s.locked++;
4917                                 }
4918                         }
4919                 }
4920
4921         /* Finish reconstruct operations initiated by the expansion process */
4922         if (sh->reconstruct_state == reconstruct_state_result) {
4923                 struct stripe_head *sh_src
4924                         = raid5_get_active_stripe(conf, sh->sector, 1, 1, 1);
4925                 if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
4926                         /* sh cannot be written until sh_src has been read.
4927                          * so arrange for sh to be delayed a little
4928                          */
4929                         set_bit(STRIPE_DELAYED, &sh->state);
4930                         set_bit(STRIPE_HANDLE, &sh->state);
4931                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
4932                                               &sh_src->state))
4933                                 atomic_inc(&conf->preread_active_stripes);
4934                         raid5_release_stripe(sh_src);
4935                         goto finish;
4936                 }
4937                 if (sh_src)
4938                         raid5_release_stripe(sh_src);
4939
4940                 sh->reconstruct_state = reconstruct_state_idle;
4941                 clear_bit(STRIPE_EXPANDING, &sh->state);
4942                 for (i = conf->raid_disks; i--; ) {
4943                         set_bit(R5_Wantwrite, &sh->dev[i].flags);
4944                         set_bit(R5_LOCKED, &sh->dev[i].flags);
4945                         s.locked++;
4946                 }
4947         }
4948
4949         if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
4950             !sh->reconstruct_state) {
4951                 /* Need to write out all blocks after computing parity */
4952                 sh->disks = conf->raid_disks;
4953                 stripe_set_idx(sh->sector, conf, 0, sh);
4954                 schedule_reconstruction(sh, &s, 1, 1);
4955         } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
4956                 clear_bit(STRIPE_EXPAND_READY, &sh->state);
4957                 atomic_dec(&conf->reshape_stripes);
4958                 wake_up(&conf->wait_for_overlap);
4959                 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
4960         }
4961
4962         if (s.expanding && s.locked == 0 &&
4963             !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
4964                 handle_stripe_expansion(conf, sh);
4965
4966 finish:
4967         /* wait for this device to become unblocked */
4968         if (unlikely(s.blocked_rdev)) {
4969                 if (conf->mddev->external)
4970                         md_wait_for_blocked_rdev(s.blocked_rdev,
4971                                                  conf->mddev);
4972                 else
4973                         /* Internal metadata will immediately
4974                          * be written by raid5d, so we don't
4975                          * need to wait here.
4976                          */
4977                         rdev_dec_pending(s.blocked_rdev,
4978                                          conf->mddev);
4979         }
4980
4981         if (s.handle_bad_blocks)
4982                 for (i = disks; i--; ) {
4983                         struct md_rdev *rdev;
4984                         struct r5dev *dev = &sh->dev[i];
4985                         if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
4986                                 /* We own a safe reference to the rdev */
4987                                 rdev = conf->disks[i].rdev;
4988                                 if (!rdev_set_badblocks(rdev, sh->sector,
4989                                                         STRIPE_SECTORS, 0))
4990                                         md_error(conf->mddev, rdev);
4991                                 rdev_dec_pending(rdev, conf->mddev);
4992                         }
4993                         if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
4994                                 rdev = conf->disks[i].rdev;
4995                                 rdev_clear_badblocks(rdev, sh->sector,
4996                                                      STRIPE_SECTORS, 0);
4997                                 rdev_dec_pending(rdev, conf->mddev);
4998                         }
4999                         if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
5000                                 rdev = conf->disks[i].replacement;
5001                                 if (!rdev)
5002                                         /* rdev have been moved down */
5003                                         rdev = conf->disks[i].rdev;
5004                                 rdev_clear_badblocks(rdev, sh->sector,
5005                                                      STRIPE_SECTORS, 0);
5006                                 rdev_dec_pending(rdev, conf->mddev);
5007                         }
5008                 }
5009
5010         if (s.ops_request)
5011                 raid_run_ops(sh, s.ops_request);
5012
5013         ops_run_io(sh, &s);
5014
5015         if (s.dec_preread_active) {
5016                 /* We delay this until after ops_run_io so that if make_request
5017                  * is waiting on a flush, it won't continue until the writes
5018                  * have actually been submitted.
5019                  */
5020                 atomic_dec(&conf->preread_active_stripes);
5021                 if (atomic_read(&conf->preread_active_stripes) <
5022                     IO_THRESHOLD)
5023                         md_wakeup_thread(conf->mddev->thread);
5024         }
5025
5026         if (!bio_list_empty(&s.return_bi)) {
5027                 if (test_bit(MD_SB_CHANGE_PENDING, &conf->mddev->sb_flags)) {
5028                         spin_lock_irq(&conf->device_lock);
5029                         bio_list_merge(&conf->return_bi, &s.return_bi);
5030                         spin_unlock_irq(&conf->device_lock);
5031                         md_wakeup_thread(conf->mddev->thread);
5032                 } else
5033                         return_io(&s.return_bi);
5034         }
5035
5036         clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
5037 }
5038
5039 static void raid5_activate_delayed(struct r5conf *conf)
5040 {
5041         if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
5042                 while (!list_empty(&conf->delayed_list)) {
5043                         struct list_head *l = conf->delayed_list.next;
5044                         struct stripe_head *sh;
5045                         sh = list_entry(l, struct stripe_head, lru);
5046                         list_del_init(l);
5047                         clear_bit(STRIPE_DELAYED, &sh->state);
5048                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5049                                 atomic_inc(&conf->preread_active_stripes);
5050                         list_add_tail(&sh->lru, &conf->hold_list);
5051                         raid5_wakeup_stripe_thread(sh);
5052                 }
5053         }
5054 }
5055
5056 static void activate_bit_delay(struct r5conf *conf,
5057         struct list_head *temp_inactive_list)
5058 {
5059         /* device_lock is held */
5060         struct list_head head;
5061         list_add(&head, &conf->bitmap_list);
5062         list_del_init(&conf->bitmap_list);
5063         while (!list_empty(&head)) {
5064                 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
5065                 int hash;
5066                 list_del_init(&sh->lru);
5067                 atomic_inc(&sh->count);
5068                 hash = sh->hash_lock_index;
5069                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
5070         }
5071 }
5072
5073 static int raid5_congested(struct mddev *mddev, int bits)
5074 {
5075         struct r5conf *conf = mddev->private;
5076
5077         /* No difference between reads and writes.  Just check
5078          * how busy the stripe_cache is
5079          */
5080
5081         if (test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
5082                 return 1;
5083
5084         /* Also checks whether there is pressure on r5cache log space */
5085         if (test_bit(R5C_LOG_TIGHT, &conf->cache_state))
5086                 return 1;
5087         if (conf->quiesce)
5088                 return 1;
5089         if (atomic_read(&conf->empty_inactive_list_nr))
5090                 return 1;
5091
5092         return 0;
5093 }
5094
5095 static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
5096 {
5097         struct r5conf *conf = mddev->private;
5098         sector_t sector = bio->bi_iter.bi_sector + get_start_sect(bio->bi_bdev);
5099         unsigned int chunk_sectors;
5100         unsigned int bio_sectors = bio_sectors(bio);
5101
5102         chunk_sectors = min(conf->chunk_sectors, conf->prev_chunk_sectors);
5103         return  chunk_sectors >=
5104                 ((sector & (chunk_sectors - 1)) + bio_sectors);
5105 }
5106
5107 /*
5108  *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
5109  *  later sampled by raid5d.
5110  */
5111 static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
5112 {
5113         unsigned long flags;
5114
5115         spin_lock_irqsave(&conf->device_lock, flags);
5116
5117         bi->bi_next = conf->retry_read_aligned_list;
5118         conf->retry_read_aligned_list = bi;
5119
5120         spin_unlock_irqrestore(&conf->device_lock, flags);
5121         md_wakeup_thread(conf->mddev->thread);
5122 }
5123
5124 static struct bio *remove_bio_from_retry(struct r5conf *conf)
5125 {
5126         struct bio *bi;
5127
5128         bi = conf->retry_read_aligned;
5129         if (bi) {
5130                 conf->retry_read_aligned = NULL;
5131                 return bi;
5132         }
5133         bi = conf->retry_read_aligned_list;
5134         if(bi) {
5135                 conf->retry_read_aligned_list = bi->bi_next;
5136                 bi->bi_next = NULL;
5137                 /*
5138                  * this sets the active strip count to 1 and the processed
5139                  * strip count to zero (upper 8 bits)
5140                  */
5141                 raid5_set_bi_stripes(bi, 1); /* biased count of active stripes */
5142         }
5143
5144         return bi;
5145 }
5146
5147 /*
5148  *  The "raid5_align_endio" should check if the read succeeded and if it
5149  *  did, call bio_endio on the original bio (having bio_put the new bio
5150  *  first).
5151  *  If the read failed..
5152  */
5153 static void raid5_align_endio(struct bio *bi)
5154 {
5155         struct bio* raid_bi  = bi->bi_private;
5156         struct mddev *mddev;
5157         struct r5conf *conf;
5158         struct md_rdev *rdev;
5159         int error = bi->bi_error;
5160
5161         bio_put(bi);
5162
5163         rdev = (void*)raid_bi->bi_next;
5164         raid_bi->bi_next = NULL;
5165         mddev = rdev->mddev;
5166         conf = mddev->private;
5167
5168         rdev_dec_pending(rdev, conf->mddev);
5169
5170         if (!error) {
5171                 trace_block_bio_complete(bdev_get_queue(raid_bi->bi_bdev),
5172                                          raid_bi, 0);
5173                 bio_endio(raid_bi);
5174                 if (atomic_dec_and_test(&conf->active_aligned_reads))
5175                         wake_up(&conf->wait_for_quiescent);
5176                 return;
5177         }
5178
5179         pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
5180
5181         add_bio_to_retry(raid_bi, conf);
5182 }
5183
5184 static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
5185 {
5186         struct r5conf *conf = mddev->private;
5187         int dd_idx;
5188         struct bio* align_bi;
5189         struct md_rdev *rdev;
5190         sector_t end_sector;
5191
5192         if (!in_chunk_boundary(mddev, raid_bio)) {
5193                 pr_debug("%s: non aligned\n", __func__);
5194                 return 0;
5195         }
5196         /*
5197          * use bio_clone_fast to make a copy of the bio
5198          */
5199         align_bi = bio_clone_fast(raid_bio, GFP_NOIO, mddev->bio_set);
5200         if (!align_bi)
5201                 return 0;
5202         /*
5203          *   set bi_end_io to a new function, and set bi_private to the
5204          *     original bio.
5205          */
5206         align_bi->bi_end_io  = raid5_align_endio;
5207         align_bi->bi_private = raid_bio;
5208         /*
5209          *      compute position
5210          */
5211         align_bi->bi_iter.bi_sector =
5212                 raid5_compute_sector(conf, raid_bio->bi_iter.bi_sector,
5213                                      0, &dd_idx, NULL);
5214
5215         end_sector = bio_end_sector(align_bi);
5216         rcu_read_lock();
5217         rdev = rcu_dereference(conf->disks[dd_idx].replacement);
5218         if (!rdev || test_bit(Faulty, &rdev->flags) ||
5219             rdev->recovery_offset < end_sector) {
5220                 rdev = rcu_dereference(conf->disks[dd_idx].rdev);
5221                 if (rdev &&
5222                     (test_bit(Faulty, &rdev->flags) ||
5223                     !(test_bit(In_sync, &rdev->flags) ||
5224                       rdev->recovery_offset >= end_sector)))
5225                         rdev = NULL;
5226         }
5227
5228         if (r5c_big_stripe_cached(conf, align_bi->bi_iter.bi_sector)) {
5229                 rcu_read_unlock();
5230                 bio_put(align_bi);
5231                 return 0;
5232         }
5233
5234         if (rdev) {
5235                 sector_t first_bad;
5236                 int bad_sectors;
5237
5238                 atomic_inc(&rdev->nr_pending);
5239                 rcu_read_unlock();
5240                 raid_bio->bi_next = (void*)rdev;
5241                 align_bi->bi_bdev =  rdev->bdev;
5242                 bio_clear_flag(align_bi, BIO_SEG_VALID);
5243
5244                 if (is_badblock(rdev, align_bi->bi_iter.bi_sector,
5245                                 bio_sectors(align_bi),
5246                                 &first_bad, &bad_sectors)) {
5247                         bio_put(align_bi);
5248                         rdev_dec_pending(rdev, mddev);
5249                         return 0;
5250                 }
5251
5252                 /* No reshape active, so we can trust rdev->data_offset */
5253                 align_bi->bi_iter.bi_sector += rdev->data_offset;
5254
5255                 spin_lock_irq(&conf->device_lock);
5256                 wait_event_lock_irq(conf->wait_for_quiescent,
5257                                     conf->quiesce == 0,
5258                                     conf->device_lock);
5259                 atomic_inc(&conf->active_aligned_reads);
5260                 spin_unlock_irq(&conf->device_lock);
5261
5262                 if (mddev->gendisk)
5263                         trace_block_bio_remap(bdev_get_queue(align_bi->bi_bdev),
5264                                               align_bi, disk_devt(mddev->gendisk),
5265                                               raid_bio->bi_iter.bi_sector);
5266                 generic_make_request(align_bi);
5267                 return 1;
5268         } else {
5269                 rcu_read_unlock();
5270                 bio_put(align_bi);
5271                 return 0;
5272         }
5273 }
5274
5275 static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
5276 {
5277         struct bio *split;
5278
5279         do {
5280                 sector_t sector = raid_bio->bi_iter.bi_sector;
5281                 unsigned chunk_sects = mddev->chunk_sectors;
5282                 unsigned sectors = chunk_sects - (sector & (chunk_sects-1));
5283
5284                 if (sectors < bio_sectors(raid_bio)) {
5285                         split = bio_split(raid_bio, sectors, GFP_NOIO, fs_bio_set);
5286                         bio_chain(split, raid_bio);
5287                 } else
5288                         split = raid_bio;
5289
5290                 if (!raid5_read_one_chunk(mddev, split)) {
5291                         if (split != raid_bio)
5292                                 generic_make_request(raid_bio);
5293                         return split;
5294                 }
5295         } while (split != raid_bio);
5296
5297         return NULL;
5298 }
5299
5300 /* __get_priority_stripe - get the next stripe to process
5301  *
5302  * Full stripe writes are allowed to pass preread active stripes up until
5303  * the bypass_threshold is exceeded.  In general the bypass_count
5304  * increments when the handle_list is handled before the hold_list; however, it
5305  * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
5306  * stripe with in flight i/o.  The bypass_count will be reset when the
5307  * head of the hold_list has changed, i.e. the head was promoted to the
5308  * handle_list.
5309  */
5310 static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group)
5311 {
5312         struct stripe_head *sh, *tmp;
5313         struct list_head *handle_list = NULL;
5314         struct r5worker_group *wg;
5315         bool second_try = !r5c_is_writeback(conf->log);
5316         bool try_loprio = test_bit(R5C_LOG_TIGHT, &conf->cache_state);
5317
5318 again:
5319         wg = NULL;
5320         sh = NULL;
5321         if (conf->worker_cnt_per_group == 0) {
5322                 handle_list = try_loprio ? &conf->loprio_list :
5323                                         &conf->handle_list;
5324         } else if (group != ANY_GROUP) {
5325                 handle_list = try_loprio ? &conf->worker_groups[group].loprio_list :
5326                                 &conf->worker_groups[group].handle_list;
5327                 wg = &conf->worker_groups[group];
5328         } else {
5329                 int i;
5330                 for (i = 0; i < conf->group_cnt; i++) {
5331                         handle_list = try_loprio ? &conf->worker_groups[i].loprio_list :
5332                                 &conf->worker_groups[i].handle_list;
5333                         wg = &conf->worker_groups[i];
5334                         if (!list_empty(handle_list))
5335                                 break;
5336                 }
5337         }
5338
5339         pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
5340                   __func__,
5341                   list_empty(handle_list) ? "empty" : "busy",
5342                   list_empty(&conf->hold_list) ? "empty" : "busy",
5343                   atomic_read(&conf->pending_full_writes), conf->bypass_count);
5344
5345         if (!list_empty(handle_list)) {
5346                 sh = list_entry(handle_list->next, typeof(*sh), lru);
5347
5348                 if (list_empty(&conf->hold_list))
5349                         conf->bypass_count = 0;
5350                 else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
5351                         if (conf->hold_list.next == conf->last_hold)
5352                                 conf->bypass_count++;
5353                         else {
5354                                 conf->last_hold = conf->hold_list.next;
5355                                 conf->bypass_count -= conf->bypass_threshold;
5356                                 if (conf->bypass_count < 0)
5357                                         conf->bypass_count = 0;
5358                         }
5359                 }
5360         } else if (!list_empty(&conf->hold_list) &&
5361                    ((conf->bypass_threshold &&
5362                      conf->bypass_count > conf->bypass_threshold) ||
5363                     atomic_read(&conf->pending_full_writes) == 0)) {
5364
5365                 list_for_each_entry(tmp, &conf->hold_list,  lru) {
5366                         if (conf->worker_cnt_per_group == 0 ||
5367                             group == ANY_GROUP ||
5368                             !cpu_online(tmp->cpu) ||
5369                             cpu_to_group(tmp->cpu) == group) {
5370                                 sh = tmp;
5371                                 break;
5372                         }
5373                 }
5374
5375                 if (sh) {
5376                         conf->bypass_count -= conf->bypass_threshold;
5377                         if (conf->bypass_count < 0)
5378                                 conf->bypass_count = 0;
5379                 }
5380                 wg = NULL;
5381         }
5382
5383         if (!sh) {
5384                 if (second_try)
5385                         return NULL;
5386                 second_try = true;
5387                 try_loprio = !try_loprio;
5388                 goto again;
5389         }
5390
5391         if (wg) {
5392                 wg->stripes_cnt--;
5393                 sh->group = NULL;
5394         }
5395         list_del_init(&sh->lru);
5396         BUG_ON(atomic_inc_return(&sh->count) != 1);
5397         return sh;
5398 }
5399
5400 struct raid5_plug_cb {
5401         struct blk_plug_cb      cb;
5402         struct list_head        list;
5403         struct list_head        temp_inactive_list[NR_STRIPE_HASH_LOCKS];
5404 };
5405
5406 static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
5407 {
5408         struct raid5_plug_cb *cb = container_of(
5409                 blk_cb, struct raid5_plug_cb, cb);
5410         struct stripe_head *sh;
5411         struct mddev *mddev = cb->cb.data;
5412         struct r5conf *conf = mddev->private;
5413         int cnt = 0;
5414         int hash;
5415
5416         if (cb->list.next && !list_empty(&cb->list)) {
5417                 spin_lock_irq(&conf->device_lock);
5418                 while (!list_empty(&cb->list)) {
5419                         sh = list_first_entry(&cb->list, struct stripe_head, lru);
5420                         list_del_init(&sh->lru);
5421                         /*
5422                          * avoid race release_stripe_plug() sees
5423                          * STRIPE_ON_UNPLUG_LIST clear but the stripe
5424                          * is still in our list
5425                          */
5426                         smp_mb__before_atomic();
5427                         clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
5428                         /*
5429                          * STRIPE_ON_RELEASE_LIST could be set here. In that
5430                          * case, the count is always > 1 here
5431                          */
5432                         hash = sh->hash_lock_index;
5433                         __release_stripe(conf, sh, &cb->temp_inactive_list[hash]);
5434                         cnt++;
5435                 }
5436                 spin_unlock_irq(&conf->device_lock);
5437         }
5438         release_inactive_stripe_list(conf, cb->temp_inactive_list,
5439                                      NR_STRIPE_HASH_LOCKS);
5440         if (mddev->queue)
5441                 trace_block_unplug(mddev->queue, cnt, !from_schedule);
5442         kfree(cb);
5443 }
5444
5445 static void release_stripe_plug(struct mddev *mddev,
5446                                 struct stripe_head *sh)
5447 {
5448         struct blk_plug_cb *blk_cb = blk_check_plugged(
5449                 raid5_unplug, mddev,
5450                 sizeof(struct raid5_plug_cb));
5451         struct raid5_plug_cb *cb;
5452
5453         if (!blk_cb) {
5454                 raid5_release_stripe(sh);
5455                 return;
5456         }
5457
5458         cb = container_of(blk_cb, struct raid5_plug_cb, cb);
5459
5460         if (cb->list.next == NULL) {
5461                 int i;
5462                 INIT_LIST_HEAD(&cb->list);
5463                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
5464                         INIT_LIST_HEAD(cb->temp_inactive_list + i);
5465         }
5466
5467         if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
5468                 list_add_tail(&sh->lru, &cb->list);
5469         else
5470                 raid5_release_stripe(sh);
5471 }
5472
5473 static void make_discard_request(struct mddev *mddev, struct bio *bi)
5474 {
5475         struct r5conf *conf = mddev->private;
5476         sector_t logical_sector, last_sector;
5477         struct stripe_head *sh;
5478         int remaining;
5479         int stripe_sectors;
5480
5481         if (mddev->reshape_position != MaxSector)
5482                 /* Skip discard while reshape is happening */
5483                 return;
5484
5485         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
5486         last_sector = bi->bi_iter.bi_sector + (bi->bi_iter.bi_size>>9);
5487
5488         bi->bi_next = NULL;
5489         bi->bi_phys_segments = 1; /* over-loaded to count active stripes */
5490
5491         stripe_sectors = conf->chunk_sectors *
5492                 (conf->raid_disks - conf->max_degraded);
5493         logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
5494                                                stripe_sectors);
5495         sector_div(last_sector, stripe_sectors);
5496
5497         logical_sector *= conf->chunk_sectors;
5498         last_sector *= conf->chunk_sectors;
5499
5500         for (; logical_sector < last_sector;
5501              logical_sector += STRIPE_SECTORS) {
5502                 DEFINE_WAIT(w);
5503                 int d;
5504         again:
5505                 sh = raid5_get_active_stripe(conf, logical_sector, 0, 0, 0);
5506                 prepare_to_wait(&conf->wait_for_overlap, &w,
5507                                 TASK_UNINTERRUPTIBLE);
5508                 set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5509                 if (test_bit(STRIPE_SYNCING, &sh->state)) {
5510                         raid5_release_stripe(sh);
5511                         schedule();
5512                         goto again;
5513                 }
5514                 clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5515                 spin_lock_irq(&sh->stripe_lock);
5516                 for (d = 0; d < conf->raid_disks; d++) {
5517                         if (d == sh->pd_idx || d == sh->qd_idx)
5518                                 continue;
5519                         if (sh->dev[d].towrite || sh->dev[d].toread) {
5520                                 set_bit(R5_Overlap, &sh->dev[d].flags);
5521                                 spin_unlock_irq(&sh->stripe_lock);
5522                                 raid5_release_stripe(sh);
5523                                 schedule();
5524                                 goto again;
5525                         }
5526                 }
5527                 set_bit(STRIPE_DISCARD, &sh->state);
5528                 finish_wait(&conf->wait_for_overlap, &w);
5529                 sh->overwrite_disks = 0;
5530                 for (d = 0; d < conf->raid_disks; d++) {
5531                         if (d == sh->pd_idx || d == sh->qd_idx)
5532                                 continue;
5533                         sh->dev[d].towrite = bi;
5534                         set_bit(R5_OVERWRITE, &sh->dev[d].flags);
5535                         raid5_inc_bi_active_stripes(bi);
5536                         sh->overwrite_disks++;
5537                 }
5538                 spin_unlock_irq(&sh->stripe_lock);
5539                 if (conf->mddev->bitmap) {
5540                         for (d = 0;
5541                              d < conf->raid_disks - conf->max_degraded;
5542                              d++)
5543                                 bitmap_startwrite(mddev->bitmap,
5544                                                   sh->sector,
5545                                                   STRIPE_SECTORS,
5546                                                   0);
5547                         sh->bm_seq = conf->seq_flush + 1;
5548                         set_bit(STRIPE_BIT_DELAY, &sh->state);
5549                 }
5550
5551                 set_bit(STRIPE_HANDLE, &sh->state);
5552                 clear_bit(STRIPE_DELAYED, &sh->state);
5553                 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5554                         atomic_inc(&conf->preread_active_stripes);
5555                 release_stripe_plug(mddev, sh);
5556         }
5557
5558         remaining = raid5_dec_bi_active_stripes(bi);
5559         if (remaining == 0) {
5560                 md_write_end(mddev);
5561                 bio_endio(bi);
5562         }
5563 }
5564
5565 static void raid5_make_request(struct mddev *mddev, struct bio * bi)
5566 {
5567         struct r5conf *conf = mddev->private;
5568         int dd_idx;
5569         sector_t new_sector;
5570         sector_t logical_sector, last_sector;
5571         struct stripe_head *sh;
5572         const int rw = bio_data_dir(bi);
5573         int remaining;
5574         DEFINE_WAIT(w);
5575         bool do_prepare;
5576         bool do_flush = false;
5577
5578         if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
5579                 int ret = r5l_handle_flush_request(conf->log, bi);
5580
5581                 if (ret == 0)
5582                         return;
5583                 if (ret == -ENODEV) {
5584                         md_flush_request(mddev, bi);
5585                         return;
5586                 }
5587                 /* ret == -EAGAIN, fallback */
5588                 /*
5589                  * if r5l_handle_flush_request() didn't clear REQ_PREFLUSH,
5590                  * we need to flush journal device
5591                  */
5592                 do_flush = bi->bi_opf & REQ_PREFLUSH;
5593         }
5594
5595         md_write_start(mddev, bi);
5596
5597         /*
5598          * If array is degraded, better not do chunk aligned read because
5599          * later we might have to read it again in order to reconstruct
5600          * data on failed drives.
5601          */
5602         if (rw == READ && mddev->degraded == 0 &&
5603             mddev->reshape_position == MaxSector) {
5604                 bi = chunk_aligned_read(mddev, bi);
5605                 if (!bi)
5606                         return;
5607         }
5608
5609         if (unlikely(bio_op(bi) == REQ_OP_DISCARD)) {
5610                 make_discard_request(mddev, bi);
5611                 return;
5612         }
5613
5614         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
5615         last_sector = bio_end_sector(bi);
5616         bi->bi_next = NULL;
5617         bi->bi_phys_segments = 1;       /* over-loaded to count active stripes */
5618
5619         prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
5620         for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
5621                 int previous;
5622                 int seq;
5623
5624                 do_prepare = false;
5625         retry:
5626                 seq = read_seqcount_begin(&conf->gen_lock);
5627                 previous = 0;
5628                 if (do_prepare)
5629                         prepare_to_wait(&conf->wait_for_overlap, &w,
5630                                 TASK_UNINTERRUPTIBLE);
5631                 if (unlikely(conf->reshape_progress != MaxSector)) {
5632                         /* spinlock is needed as reshape_progress may be
5633                          * 64bit on a 32bit platform, and so it might be
5634                          * possible to see a half-updated value
5635                          * Of course reshape_progress could change after
5636                          * the lock is dropped, so once we get a reference
5637                          * to the stripe that we think it is, we will have
5638                          * to check again.
5639                          */
5640                         spin_lock_irq(&conf->device_lock);
5641                         if (mddev->reshape_backwards
5642                             ? logical_sector < conf->reshape_progress
5643                             : logical_sector >= conf->reshape_progress) {
5644                                 previous = 1;
5645                         } else {
5646                                 if (mddev->reshape_backwards
5647                                     ? logical_sector < conf->reshape_safe
5648                                     : logical_sector >= conf->reshape_safe) {
5649                                         spin_unlock_irq(&conf->device_lock);
5650                                         schedule();
5651                                         do_prepare = true;
5652                                         goto retry;
5653                                 }
5654                         }
5655                         spin_unlock_irq(&conf->device_lock);
5656                 }
5657
5658                 new_sector = raid5_compute_sector(conf, logical_sector,
5659                                                   previous,
5660                                                   &dd_idx, NULL);
5661                 pr_debug("raid456: raid5_make_request, sector %llu logical %llu\n",
5662                         (unsigned long long)new_sector,
5663                         (unsigned long long)logical_sector);
5664
5665                 sh = raid5_get_active_stripe(conf, new_sector, previous,
5666                                        (bi->bi_opf & REQ_RAHEAD), 0);
5667                 if (sh) {
5668                         if (unlikely(previous)) {
5669                                 /* expansion might have moved on while waiting for a
5670                                  * stripe, so we must do the range check again.
5671                                  * Expansion could still move past after this
5672                                  * test, but as we are holding a reference to
5673                                  * 'sh', we know that if that happens,
5674                                  *  STRIPE_EXPANDING will get set and the expansion
5675                                  * won't proceed until we finish with the stripe.
5676                                  */
5677                                 int must_retry = 0;
5678                                 spin_lock_irq(&conf->device_lock);
5679                                 if (mddev->reshape_backwards
5680                                     ? logical_sector >= conf->reshape_progress
5681                                     : logical_sector < conf->reshape_progress)
5682                                         /* mismatch, need to try again */
5683                                         must_retry = 1;
5684                                 spin_unlock_irq(&conf->device_lock);
5685                                 if (must_retry) {
5686                                         raid5_release_stripe(sh);
5687                                         schedule();
5688                                         do_prepare = true;
5689                                         goto retry;
5690                                 }
5691                         }
5692                         if (read_seqcount_retry(&conf->gen_lock, seq)) {
5693                                 /* Might have got the wrong stripe_head
5694                                  * by accident
5695                                  */
5696                                 raid5_release_stripe(sh);
5697                                 goto retry;
5698                         }
5699
5700                         if (rw == WRITE &&
5701                             logical_sector >= mddev->suspend_lo &&
5702                             logical_sector < mddev->suspend_hi) {
5703                                 raid5_release_stripe(sh);
5704                                 /* As the suspend_* range is controlled by
5705                                  * userspace, we want an interruptible
5706                                  * wait.
5707                                  */
5708                                 flush_signals(current);
5709                                 prepare_to_wait(&conf->wait_for_overlap,
5710                                                 &w, TASK_INTERRUPTIBLE);
5711                                 if (logical_sector >= mddev->suspend_lo &&
5712                                     logical_sector < mddev->suspend_hi) {
5713                                         schedule();
5714                                         do_prepare = true;
5715                                 }
5716                                 goto retry;
5717                         }
5718
5719                         if (test_bit(STRIPE_EXPANDING, &sh->state) ||
5720                             !add_stripe_bio(sh, bi, dd_idx, rw, previous)) {
5721                                 /* Stripe is busy expanding or
5722                                  * add failed due to overlap.  Flush everything
5723                                  * and wait a while
5724                                  */
5725                                 md_wakeup_thread(mddev->thread);
5726                                 raid5_release_stripe(sh);
5727                                 schedule();
5728                                 do_prepare = true;
5729                                 goto retry;
5730                         }
5731                         if (do_flush) {
5732                                 set_bit(STRIPE_R5C_PREFLUSH, &sh->state);
5733                                 /* we only need flush for one stripe */
5734                                 do_flush = false;
5735                         }
5736
5737                         set_bit(STRIPE_HANDLE, &sh->state);
5738                         clear_bit(STRIPE_DELAYED, &sh->state);
5739                         if ((!sh->batch_head || sh == sh->batch_head) &&
5740                             (bi->bi_opf & REQ_SYNC) &&
5741                             !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5742                                 atomic_inc(&conf->preread_active_stripes);
5743                         release_stripe_plug(mddev, sh);
5744                 } else {
5745                         /* cannot get stripe for read-ahead, just give-up */
5746                         bi->bi_error = -EIO;
5747                         break;
5748                 }
5749         }
5750         finish_wait(&conf->wait_for_overlap, &w);
5751
5752         remaining = raid5_dec_bi_active_stripes(bi);
5753         if (remaining == 0) {
5754
5755                 if ( rw == WRITE )
5756                         md_write_end(mddev);
5757
5758                 trace_block_bio_complete(bdev_get_queue(bi->bi_bdev),
5759                                          bi, 0);
5760                 bio_endio(bi);
5761         }
5762 }
5763
5764 static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
5765
5766 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
5767 {
5768         /* reshaping is quite different to recovery/resync so it is
5769          * handled quite separately ... here.
5770          *
5771          * On each call to sync_request, we gather one chunk worth of
5772          * destination stripes and flag them as expanding.
5773          * Then we find all the source stripes and request reads.
5774          * As the reads complete, handle_stripe will copy the data
5775          * into the destination stripe and release that stripe.
5776          */
5777         struct r5conf *conf = mddev->private;
5778         struct stripe_head *sh;
5779         sector_t first_sector, last_sector;
5780         int raid_disks = conf->previous_raid_disks;
5781         int data_disks = raid_disks - conf->max_degraded;
5782         int new_data_disks = conf->raid_disks - conf->max_degraded;
5783         int i;
5784         int dd_idx;
5785         sector_t writepos, readpos, safepos;
5786         sector_t stripe_addr;
5787         int reshape_sectors;
5788         struct list_head stripes;
5789         sector_t retn;
5790
5791         if (sector_nr == 0) {
5792                 /* If restarting in the middle, skip the initial sectors */
5793                 if (mddev->reshape_backwards &&
5794                     conf->reshape_progress < raid5_size(mddev, 0, 0)) {
5795                         sector_nr = raid5_size(mddev, 0, 0)
5796                                 - conf->reshape_progress;
5797                 } else if (mddev->reshape_backwards &&
5798                            conf->reshape_progress == MaxSector) {
5799                         /* shouldn't happen, but just in case, finish up.*/
5800                         sector_nr = MaxSector;
5801                 } else if (!mddev->reshape_backwards &&
5802                            conf->reshape_progress > 0)
5803                         sector_nr = conf->reshape_progress;
5804                 sector_div(sector_nr, new_data_disks);
5805                 if (sector_nr) {
5806                         mddev->curr_resync_completed = sector_nr;
5807                         sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5808                         *skipped = 1;
5809                         retn = sector_nr;
5810                         goto finish;
5811                 }
5812         }
5813
5814         /* We need to process a full chunk at a time.
5815          * If old and new chunk sizes differ, we need to process the
5816          * largest of these
5817          */
5818
5819         reshape_sectors = max(conf->chunk_sectors, conf->prev_chunk_sectors);
5820
5821         /* We update the metadata at least every 10 seconds, or when
5822          * the data about to be copied would over-write the source of
5823          * the data at the front of the range.  i.e. one new_stripe
5824          * along from reshape_progress new_maps to after where
5825          * reshape_safe old_maps to
5826          */
5827         writepos = conf->reshape_progress;
5828         sector_div(writepos, new_data_disks);
5829         readpos = conf->reshape_progress;
5830         sector_div(readpos, data_disks);
5831         safepos = conf->reshape_safe;
5832         sector_div(safepos, data_disks);
5833         if (mddev->reshape_backwards) {
5834                 BUG_ON(writepos < reshape_sectors);
5835                 writepos -= reshape_sectors;
5836                 readpos += reshape_sectors;
5837                 safepos += reshape_sectors;
5838         } else {
5839                 writepos += reshape_sectors;
5840                 /* readpos and safepos are worst-case calculations.
5841                  * A negative number is overly pessimistic, and causes
5842                  * obvious problems for unsigned storage.  So clip to 0.
5843                  */
5844                 readpos -= min_t(sector_t, reshape_sectors, readpos);
5845                 safepos -= min_t(sector_t, reshape_sectors, safepos);
5846         }
5847
5848         /* Having calculated the 'writepos' possibly use it
5849          * to set 'stripe_addr' which is where we will write to.
5850          */
5851         if (mddev->reshape_backwards) {
5852                 BUG_ON(conf->reshape_progress == 0);
5853                 stripe_addr = writepos;
5854                 BUG_ON((mddev->dev_sectors &
5855                         ~((sector_t)reshape_sectors - 1))
5856                        - reshape_sectors - stripe_addr
5857                        != sector_nr);
5858         } else {
5859                 BUG_ON(writepos != sector_nr + reshape_sectors);
5860                 stripe_addr = sector_nr;
5861         }
5862
5863         /* 'writepos' is the most advanced device address we might write.
5864          * 'readpos' is the least advanced device address we might read.
5865          * 'safepos' is the least address recorded in the metadata as having
5866          *     been reshaped.
5867          * If there is a min_offset_diff, these are adjusted either by
5868          * increasing the safepos/readpos if diff is negative, or
5869          * increasing writepos if diff is positive.
5870          * If 'readpos' is then behind 'writepos', there is no way that we can
5871          * ensure safety in the face of a crash - that must be done by userspace
5872          * making a backup of the data.  So in that case there is no particular
5873          * rush to update metadata.
5874          * Otherwise if 'safepos' is behind 'writepos', then we really need to
5875          * update the metadata to advance 'safepos' to match 'readpos' so that
5876          * we can be safe in the event of a crash.
5877          * So we insist on updating metadata if safepos is behind writepos and
5878          * readpos is beyond writepos.
5879          * In any case, update the metadata every 10 seconds.
5880          * Maybe that number should be configurable, but I'm not sure it is
5881          * worth it.... maybe it could be a multiple of safemode_delay???
5882          */
5883         if (conf->min_offset_diff < 0) {
5884                 safepos += -conf->min_offset_diff;
5885                 readpos += -conf->min_offset_diff;
5886         } else
5887                 writepos += conf->min_offset_diff;
5888
5889         if ((mddev->reshape_backwards
5890              ? (safepos > writepos && readpos < writepos)
5891              : (safepos < writepos && readpos > writepos)) ||
5892             time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
5893                 /* Cannot proceed until we've updated the superblock... */
5894                 wait_event(conf->wait_for_overlap,
5895                            atomic_read(&conf->reshape_stripes)==0
5896                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5897                 if (atomic_read(&conf->reshape_stripes) != 0)
5898                         return 0;
5899                 mddev->reshape_position = conf->reshape_progress;
5900                 mddev->curr_resync_completed = sector_nr;
5901                 conf->reshape_checkpoint = jiffies;
5902                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
5903                 md_wakeup_thread(mddev->thread);
5904                 wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
5905                            test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5906                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5907                         return 0;
5908                 spin_lock_irq(&conf->device_lock);
5909                 conf->reshape_safe = mddev->reshape_position;
5910                 spin_unlock_irq(&conf->device_lock);
5911                 wake_up(&conf->wait_for_overlap);
5912                 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5913         }
5914
5915         INIT_LIST_HEAD(&stripes);
5916         for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
5917                 int j;
5918                 int skipped_disk = 0;
5919                 sh = raid5_get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
5920                 set_bit(STRIPE_EXPANDING, &sh->state);
5921                 atomic_inc(&conf->reshape_stripes);
5922                 /* If any of this stripe is beyond the end of the old
5923                  * array, then we need to zero those blocks
5924                  */
5925                 for (j=sh->disks; j--;) {
5926                         sector_t s;
5927                         if (j == sh->pd_idx)
5928                                 continue;
5929                         if (conf->level == 6 &&
5930                             j == sh->qd_idx)
5931                                 continue;
5932                         s = raid5_compute_blocknr(sh, j, 0);
5933                         if (s < raid5_size(mddev, 0, 0)) {
5934                                 skipped_disk = 1;
5935                                 continue;
5936                         }
5937                         memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE);
5938                         set_bit(R5_Expanded, &sh->dev[j].flags);
5939                         set_bit(R5_UPTODATE, &sh->dev[j].flags);
5940                 }
5941                 if (!skipped_disk) {
5942                         set_bit(STRIPE_EXPAND_READY, &sh->state);
5943                         set_bit(STRIPE_HANDLE, &sh->state);
5944                 }
5945                 list_add(&sh->lru, &stripes);
5946         }
5947         spin_lock_irq(&conf->device_lock);
5948         if (mddev->reshape_backwards)
5949                 conf->reshape_progress -= reshape_sectors * new_data_disks;
5950         else
5951                 conf->reshape_progress += reshape_sectors * new_data_disks;
5952         spin_unlock_irq(&conf->device_lock);
5953         /* Ok, those stripe are ready. We can start scheduling
5954          * reads on the source stripes.
5955          * The source stripes are determined by mapping the first and last
5956          * block on the destination stripes.
5957          */
5958         first_sector =
5959                 raid5_compute_sector(conf, stripe_addr*(new_data_disks),
5960                                      1, &dd_idx, NULL);
5961         last_sector =
5962                 raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
5963                                             * new_data_disks - 1),
5964                                      1, &dd_idx, NULL);
5965         if (last_sector >= mddev->dev_sectors)
5966                 last_sector = mddev->dev_sectors - 1;
5967         while (first_sector <= last_sector) {
5968                 sh = raid5_get_active_stripe(conf, first_sector, 1, 0, 1);
5969                 set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
5970                 set_bit(STRIPE_HANDLE, &sh->state);
5971                 raid5_release_stripe(sh);
5972                 first_sector += STRIPE_SECTORS;
5973         }
5974         /* Now that the sources are clearly marked, we can release
5975          * the destination stripes
5976          */
5977         while (!list_empty(&stripes)) {
5978                 sh = list_entry(stripes.next, struct stripe_head, lru);
5979                 list_del_init(&sh->lru);
5980                 raid5_release_stripe(sh);
5981         }
5982         /* If this takes us to the resync_max point where we have to pause,
5983          * then we need to write out the superblock.
5984          */
5985         sector_nr += reshape_sectors;
5986         retn = reshape_sectors;
5987 finish:
5988         if (mddev->curr_resync_completed > mddev->resync_max ||
5989             (sector_nr - mddev->curr_resync_completed) * 2
5990             >= mddev->resync_max - mddev->curr_resync_completed) {
5991                 /* Cannot proceed until we've updated the superblock... */
5992                 wait_event(conf->wait_for_overlap,
5993                            atomic_read(&conf->reshape_stripes) == 0
5994                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5995                 if (atomic_read(&conf->reshape_stripes) != 0)
5996                         goto ret;
5997                 mddev->reshape_position = conf->reshape_progress;
5998                 mddev->curr_resync_completed = sector_nr;
5999                 conf->reshape_checkpoint = jiffies;
6000                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
6001                 md_wakeup_thread(mddev->thread);
6002                 wait_event(mddev->sb_wait,
6003                            !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)
6004                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6005                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6006                         goto ret;
6007                 spin_lock_irq(&conf->device_lock);
6008                 conf->reshape_safe = mddev->reshape_position;
6009                 spin_unlock_irq(&conf->device_lock);
6010                 wake_up(&conf->wait_for_overlap);
6011                 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
6012         }
6013 ret:
6014         return retn;
6015 }
6016
6017 static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_nr,
6018                                           int *skipped)
6019 {
6020         struct r5conf *conf = mddev->private;
6021         struct stripe_head *sh;
6022         sector_t max_sector = mddev->dev_sectors;
6023         sector_t sync_blocks;
6024         int still_degraded = 0;
6025         int i;
6026
6027         if (sector_nr >= max_sector) {
6028                 /* just being told to finish up .. nothing much to do */
6029
6030                 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
6031                         end_reshape(conf);
6032                         return 0;
6033                 }
6034
6035                 if (mddev->curr_resync < max_sector) /* aborted */
6036                         bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
6037                                         &sync_blocks, 1);
6038                 else /* completed sync */
6039                         conf->fullsync = 0;
6040                 bitmap_close_sync(mddev->bitmap);
6041
6042                 return 0;
6043         }
6044
6045         /* Allow raid5_quiesce to complete */
6046         wait_event(conf->wait_for_overlap, conf->quiesce != 2);
6047
6048         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6049                 return reshape_request(mddev, sector_nr, skipped);
6050
6051         /* No need to check resync_max as we never do more than one
6052          * stripe, and as resync_max will always be on a chunk boundary,
6053          * if the check in md_do_sync didn't fire, there is no chance
6054          * of overstepping resync_max here
6055          */
6056
6057         /* if there is too many failed drives and we are trying
6058          * to resync, then assert that we are finished, because there is
6059          * nothing we can do.
6060          */
6061         if (mddev->degraded >= conf->max_degraded &&
6062             test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
6063                 sector_t rv = mddev->dev_sectors - sector_nr;
6064                 *skipped = 1;
6065                 return rv;
6066         }
6067         if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
6068             !conf->fullsync &&
6069             !bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
6070             sync_blocks >= STRIPE_SECTORS) {
6071                 /* we can skip this block, and probably more */
6072                 sync_blocks /= STRIPE_SECTORS;
6073                 *skipped = 1;
6074                 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
6075         }
6076
6077         bitmap_cond_end_sync(mddev->bitmap, sector_nr, false);
6078
6079         sh = raid5_get_active_stripe(conf, sector_nr, 0, 1, 0);
6080         if (sh == NULL) {
6081                 sh = raid5_get_active_stripe(conf, sector_nr, 0, 0, 0);
6082                 /* make sure we don't swamp the stripe cache if someone else
6083                  * is trying to get access
6084                  */
6085                 schedule_timeout_uninterruptible(1);
6086         }
6087         /* Need to check if array will still be degraded after recovery/resync
6088          * Note in case of > 1 drive failures it's possible we're rebuilding
6089          * one drive while leaving another faulty drive in array.
6090          */
6091         rcu_read_lock();
6092         for (i = 0; i < conf->raid_disks; i++) {
6093                 struct md_rdev *rdev = ACCESS_ONCE(conf->disks[i].rdev);
6094
6095                 if (rdev == NULL || test_bit(Faulty, &rdev->flags))
6096                         still_degraded = 1;
6097         }
6098         rcu_read_unlock();
6099
6100         bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
6101
6102         set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
6103         set_bit(STRIPE_HANDLE, &sh->state);
6104
6105         raid5_release_stripe(sh);
6106
6107         return STRIPE_SECTORS;
6108 }
6109
6110 static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio)
6111 {
6112         /* We may not be able to submit a whole bio at once as there
6113          * may not be enough stripe_heads available.
6114          * We cannot pre-allocate enough stripe_heads as we may need
6115          * more than exist in the cache (if we allow ever large chunks).
6116          * So we do one stripe head at a time and record in
6117          * ->bi_hw_segments how many have been done.
6118          *
6119          * We *know* that this entire raid_bio is in one chunk, so
6120          * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
6121          */
6122         struct stripe_head *sh;
6123         int dd_idx;
6124         sector_t sector, logical_sector, last_sector;
6125         int scnt = 0;
6126         int remaining;
6127         int handled = 0;
6128
6129         logical_sector = raid_bio->bi_iter.bi_sector &
6130                 ~((sector_t)STRIPE_SECTORS-1);
6131         sector = raid5_compute_sector(conf, logical_sector,
6132                                       0, &dd_idx, NULL);
6133         last_sector = bio_end_sector(raid_bio);
6134
6135         for (; logical_sector < last_sector;
6136              logical_sector += STRIPE_SECTORS,
6137                      sector += STRIPE_SECTORS,
6138                      scnt++) {
6139
6140                 if (scnt < raid5_bi_processed_stripes(raid_bio))
6141                         /* already done this stripe */
6142                         continue;
6143
6144                 sh = raid5_get_active_stripe(conf, sector, 0, 1, 1);
6145
6146                 if (!sh) {
6147                         /* failed to get a stripe - must wait */
6148                         raid5_set_bi_processed_stripes(raid_bio, scnt);
6149                         conf->retry_read_aligned = raid_bio;
6150                         return handled;
6151                 }
6152
6153                 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0, 0)) {
6154                         raid5_release_stripe(sh);
6155                         raid5_set_bi_processed_stripes(raid_bio, scnt);
6156                         conf->retry_read_aligned = raid_bio;
6157                         return handled;
6158                 }
6159
6160                 set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
6161                 handle_stripe(sh);
6162                 raid5_release_stripe(sh);
6163                 handled++;
6164         }
6165         remaining = raid5_dec_bi_active_stripes(raid_bio);
6166         if (remaining == 0) {
6167                 trace_block_bio_complete(bdev_get_queue(raid_bio->bi_bdev),
6168                                          raid_bio, 0);
6169                 bio_endio(raid_bio);
6170         }
6171         if (atomic_dec_and_test(&conf->active_aligned_reads))
6172                 wake_up(&conf->wait_for_quiescent);
6173         return handled;
6174 }
6175
6176 static int handle_active_stripes(struct r5conf *conf, int group,
6177                                  struct r5worker *worker,
6178                                  struct list_head *temp_inactive_list)
6179 {
6180         struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
6181         int i, batch_size = 0, hash;
6182         bool release_inactive = false;
6183
6184         while (batch_size < MAX_STRIPE_BATCH &&
6185                         (sh = __get_priority_stripe(conf, group)) != NULL)
6186                 batch[batch_size++] = sh;
6187
6188         if (batch_size == 0) {
6189                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6190                         if (!list_empty(temp_inactive_list + i))
6191                                 break;
6192                 if (i == NR_STRIPE_HASH_LOCKS) {
6193                         spin_unlock_irq(&conf->device_lock);
6194                         r5l_flush_stripe_to_raid(conf->log);
6195                         spin_lock_irq(&conf->device_lock);
6196                         return batch_size;
6197                 }
6198                 release_inactive = true;
6199         }
6200         spin_unlock_irq(&conf->device_lock);
6201
6202         release_inactive_stripe_list(conf, temp_inactive_list,
6203                                      NR_STRIPE_HASH_LOCKS);
6204
6205         r5l_flush_stripe_to_raid(conf->log);
6206         if (release_inactive) {
6207                 spin_lock_irq(&conf->device_lock);
6208                 return 0;
6209         }
6210
6211         for (i = 0; i < batch_size; i++)
6212                 handle_stripe(batch[i]);
6213         log_write_stripe_run(conf);
6214
6215         cond_resched();
6216
6217         spin_lock_irq(&conf->device_lock);
6218         for (i = 0; i < batch_size; i++) {
6219                 hash = batch[i]->hash_lock_index;
6220                 __release_stripe(conf, batch[i], &temp_inactive_list[hash]);
6221         }
6222         return batch_size;
6223 }
6224
6225 static void raid5_do_work(struct work_struct *work)
6226 {
6227         struct r5worker *worker = container_of(work, struct r5worker, work);
6228         struct r5worker_group *group = worker->group;
6229         struct r5conf *conf = group->conf;
6230         int group_id = group - conf->worker_groups;
6231         int handled;
6232         struct blk_plug plug;
6233
6234         pr_debug("+++ raid5worker active\n");
6235
6236         blk_start_plug(&plug);
6237         handled = 0;
6238         spin_lock_irq(&conf->device_lock);
6239         while (1) {
6240                 int batch_size, released;
6241
6242                 released = release_stripe_list(conf, worker->temp_inactive_list);
6243
6244                 batch_size = handle_active_stripes(conf, group_id, worker,
6245                                                    worker->temp_inactive_list);
6246                 worker->working = false;
6247                 if (!batch_size && !released)
6248                         break;
6249                 handled += batch_size;
6250         }
6251         pr_debug("%d stripes handled\n", handled);
6252
6253         spin_unlock_irq(&conf->device_lock);
6254         blk_finish_plug(&plug);
6255
6256         pr_debug("--- raid5worker inactive\n");
6257 }
6258
6259 /*
6260  * This is our raid5 kernel thread.
6261  *
6262  * We scan the hash table for stripes which can be handled now.
6263  * During the scan, completed stripes are saved for us by the interrupt
6264  * handler, so that they will not have to wait for our next wakeup.
6265  */
6266 static void raid5d(struct md_thread *thread)
6267 {
6268         struct mddev *mddev = thread->mddev;
6269         struct r5conf *conf = mddev->private;
6270         int handled;
6271         struct blk_plug plug;
6272
6273         pr_debug("+++ raid5d active\n");
6274
6275         md_check_recovery(mddev);
6276
6277         if (!bio_list_empty(&conf->return_bi) &&
6278             !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
6279                 struct bio_list tmp = BIO_EMPTY_LIST;
6280                 spin_lock_irq(&conf->device_lock);
6281                 if (!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
6282                         bio_list_merge(&tmp, &conf->return_bi);
6283                         bio_list_init(&conf->return_bi);
6284                 }
6285                 spin_unlock_irq(&conf->device_lock);
6286                 return_io(&tmp);
6287         }
6288
6289         blk_start_plug(&plug);
6290         handled = 0;
6291         spin_lock_irq(&conf->device_lock);
6292         while (1) {
6293                 struct bio *bio;
6294                 int batch_size, released;
6295
6296                 released = release_stripe_list(conf, conf->temp_inactive_list);
6297                 if (released)
6298                         clear_bit(R5_DID_ALLOC, &conf->cache_state);
6299
6300                 if (
6301                     !list_empty(&conf->bitmap_list)) {
6302                         /* Now is a good time to flush some bitmap updates */
6303                         conf->seq_flush++;
6304                         spin_unlock_irq(&conf->device_lock);
6305                         bitmap_unplug(mddev->bitmap);
6306                         spin_lock_irq(&conf->device_lock);
6307                         conf->seq_write = conf->seq_flush;
6308                         activate_bit_delay(conf, conf->temp_inactive_list);
6309                 }
6310                 raid5_activate_delayed(conf);
6311
6312                 while ((bio = remove_bio_from_retry(conf))) {
6313                         int ok;
6314                         spin_unlock_irq(&conf->device_lock);
6315                         ok = retry_aligned_read(conf, bio);
6316                         spin_lock_irq(&conf->device_lock);
6317                         if (!ok)
6318                                 break;
6319                         handled++;
6320                 }
6321
6322                 batch_size = handle_active_stripes(conf, ANY_GROUP, NULL,
6323                                                    conf->temp_inactive_list);
6324                 if (!batch_size && !released)
6325                         break;
6326                 handled += batch_size;
6327
6328                 if (mddev->sb_flags & ~(1 << MD_SB_CHANGE_PENDING)) {
6329                         spin_unlock_irq(&conf->device_lock);
6330                         md_check_recovery(mddev);
6331                         spin_lock_irq(&conf->device_lock);
6332                 }
6333         }
6334         pr_debug("%d stripes handled\n", handled);
6335
6336         spin_unlock_irq(&conf->device_lock);
6337         if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state) &&
6338             mutex_trylock(&conf->cache_size_mutex)) {
6339                 grow_one_stripe(conf, __GFP_NOWARN);
6340                 /* Set flag even if allocation failed.  This helps
6341                  * slow down allocation requests when mem is short
6342                  */
6343                 set_bit(R5_DID_ALLOC, &conf->cache_state);
6344                 mutex_unlock(&conf->cache_size_mutex);
6345         }
6346
6347         flush_deferred_bios(conf);
6348
6349         r5l_flush_stripe_to_raid(conf->log);
6350
6351         async_tx_issue_pending_all();
6352         blk_finish_plug(&plug);
6353
6354         pr_debug("--- raid5d inactive\n");
6355 }
6356
6357 static ssize_t
6358 raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
6359 {
6360         struct r5conf *conf;
6361         int ret = 0;
6362         spin_lock(&mddev->lock);
6363         conf = mddev->private;
6364         if (conf)
6365                 ret = sprintf(page, "%d\n", conf->min_nr_stripes);
6366         spin_unlock(&mddev->lock);
6367         return ret;
6368 }
6369
6370 int
6371 raid5_set_cache_size(struct mddev *mddev, int size)
6372 {
6373         struct r5conf *conf = mddev->private;
6374         int err;
6375
6376         if (size <= 16 || size > 32768)
6377                 return -EINVAL;
6378
6379         conf->min_nr_stripes = size;
6380         mutex_lock(&conf->cache_size_mutex);
6381         while (size < conf->max_nr_stripes &&
6382                drop_one_stripe(conf))
6383                 ;
6384         mutex_unlock(&conf->cache_size_mutex);
6385
6386
6387         err = md_allow_write(mddev);
6388         if (err)
6389                 return err;
6390
6391         mutex_lock(&conf->cache_size_mutex);
6392         while (size > conf->max_nr_stripes)
6393                 if (!grow_one_stripe(conf, GFP_KERNEL))
6394                         break;
6395         mutex_unlock(&conf->cache_size_mutex);
6396
6397         return 0;
6398 }
6399 EXPORT_SYMBOL(raid5_set_cache_size);
6400
6401 static ssize_t
6402 raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
6403 {
6404         struct r5conf *conf;
6405         unsigned long new;
6406         int err;
6407
6408         if (len >= PAGE_SIZE)
6409                 return -EINVAL;
6410         if (kstrtoul(page, 10, &new))
6411                 return -EINVAL;
6412         err = mddev_lock(mddev);
6413         if (err)
6414                 return err;
6415         conf = mddev->private;
6416         if (!conf)
6417                 err = -ENODEV;
6418         else
6419                 err = raid5_set_cache_size(mddev, new);
6420         mddev_unlock(mddev);
6421
6422         return err ?: len;
6423 }
6424
6425 static struct md_sysfs_entry
6426 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
6427                                 raid5_show_stripe_cache_size,
6428                                 raid5_store_stripe_cache_size);
6429
6430 static ssize_t
6431 raid5_show_rmw_level(struct mddev  *mddev, char *page)
6432 {
6433         struct r5conf *conf = mddev->private;
6434         if (conf)
6435                 return sprintf(page, "%d\n", conf->rmw_level);
6436         else
6437                 return 0;
6438 }
6439
6440 static ssize_t
6441 raid5_store_rmw_level(struct mddev  *mddev, const char *page, size_t len)
6442 {
6443         struct r5conf *conf = mddev->private;
6444         unsigned long new;
6445
6446         if (!conf)
6447                 return -ENODEV;
6448
6449         if (len >= PAGE_SIZE)
6450                 return -EINVAL;
6451
6452         if (kstrtoul(page, 10, &new))
6453                 return -EINVAL;
6454
6455         if (new != PARITY_DISABLE_RMW && !raid6_call.xor_syndrome)
6456                 return -EINVAL;
6457
6458         if (new != PARITY_DISABLE_RMW &&
6459             new != PARITY_ENABLE_RMW &&
6460             new != PARITY_PREFER_RMW)
6461                 return -EINVAL;
6462
6463         conf->rmw_level = new;
6464         return len;
6465 }
6466
6467 static struct md_sysfs_entry
6468 raid5_rmw_level = __ATTR(rmw_level, S_IRUGO | S_IWUSR,
6469                          raid5_show_rmw_level,
6470                          raid5_store_rmw_level);
6471
6472
6473 static ssize_t
6474 raid5_show_preread_threshold(struct mddev *mddev, char *page)
6475 {
6476         struct r5conf *conf;
6477         int ret = 0;
6478         spin_lock(&mddev->lock);
6479         conf = mddev->private;
6480         if (conf)
6481                 ret = sprintf(page, "%d\n", conf->bypass_threshold);
6482         spin_unlock(&mddev->lock);
6483         return ret;
6484 }
6485
6486 static ssize_t
6487 raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
6488 {
6489         struct r5conf *conf;
6490         unsigned long new;
6491         int err;
6492
6493         if (len >= PAGE_SIZE)
6494                 return -EINVAL;
6495         if (kstrtoul(page, 10, &new))
6496                 return -EINVAL;
6497
6498         err = mddev_lock(mddev);
6499         if (err)
6500                 return err;
6501         conf = mddev->private;
6502         if (!conf)
6503                 err = -ENODEV;
6504         else if (new > conf->min_nr_stripes)
6505                 err = -EINVAL;
6506         else
6507                 conf->bypass_threshold = new;
6508         mddev_unlock(mddev);
6509         return err ?: len;
6510 }
6511
6512 static struct md_sysfs_entry
6513 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
6514                                         S_IRUGO | S_IWUSR,
6515                                         raid5_show_preread_threshold,
6516                                         raid5_store_preread_threshold);
6517
6518 static ssize_t
6519 raid5_show_skip_copy(struct mddev *mddev, char *page)
6520 {
6521         struct r5conf *conf;
6522         int ret = 0;
6523         spin_lock(&mddev->lock);
6524         conf = mddev->private;
6525         if (conf)
6526                 ret = sprintf(page, "%d\n", conf->skip_copy);
6527         spin_unlock(&mddev->lock);
6528         return ret;
6529 }
6530
6531 static ssize_t
6532 raid5_store_skip_copy(struct mddev *mddev, const char *page, size_t len)
6533 {
6534         struct r5conf *conf;
6535         unsigned long new;
6536         int err;
6537
6538         if (len >= PAGE_SIZE)
6539                 return -EINVAL;
6540         if (kstrtoul(page, 10, &new))
6541                 return -EINVAL;
6542         new = !!new;
6543
6544         err = mddev_lock(mddev);
6545         if (err)
6546                 return err;
6547         conf = mddev->private;
6548         if (!conf)
6549                 err = -ENODEV;
6550         else if (new != conf->skip_copy) {
6551                 mddev_suspend(mddev);
6552                 conf->skip_copy = new;
6553                 if (new)
6554                         mddev->queue->backing_dev_info->capabilities |=
6555                                 BDI_CAP_STABLE_WRITES;
6556                 else
6557                         mddev->queue->backing_dev_info->capabilities &=
6558                                 ~BDI_CAP_STABLE_WRITES;
6559                 mddev_resume(mddev);
6560         }
6561         mddev_unlock(mddev);
6562         return err ?: len;
6563 }
6564
6565 static struct md_sysfs_entry
6566 raid5_skip_copy = __ATTR(skip_copy, S_IRUGO | S_IWUSR,
6567                                         raid5_show_skip_copy,
6568                                         raid5_store_skip_copy);
6569
6570 static ssize_t
6571 stripe_cache_active_show(struct mddev *mddev, char *page)
6572 {
6573         struct r5conf *conf = mddev->private;
6574         if (conf)
6575                 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
6576         else
6577                 return 0;
6578 }
6579
6580 static struct md_sysfs_entry
6581 raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
6582
6583 static ssize_t
6584 raid5_show_group_thread_cnt(struct mddev *mddev, char *page)
6585 {
6586         struct r5conf *conf;
6587         int ret = 0;
6588         spin_lock(&mddev->lock);
6589         conf = mddev->private;
6590         if (conf)
6591                 ret = sprintf(page, "%d\n", conf->worker_cnt_per_group);
6592         spin_unlock(&mddev->lock);
6593         return ret;
6594 }
6595
6596 static int alloc_thread_groups(struct r5conf *conf, int cnt,
6597                                int *group_cnt,
6598                                int *worker_cnt_per_group,
6599                                struct r5worker_group **worker_groups);
6600 static ssize_t
6601 raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
6602 {
6603         struct r5conf *conf;
6604         unsigned long new;
6605         int err;
6606         struct r5worker_group *new_groups, *old_groups;
6607         int group_cnt, worker_cnt_per_group;
6608
6609         if (len >= PAGE_SIZE)
6610                 return -EINVAL;
6611         if (kstrtoul(page, 10, &new))
6612                 return -EINVAL;
6613
6614         err = mddev_lock(mddev);
6615         if (err)
6616                 return err;
6617         conf = mddev->private;
6618         if (!conf)
6619                 err = -ENODEV;
6620         else if (new != conf->worker_cnt_per_group) {
6621                 mddev_suspend(mddev);
6622
6623                 old_groups = conf->worker_groups;
6624                 if (old_groups)
6625                         flush_workqueue(raid5_wq);
6626
6627                 err = alloc_thread_groups(conf, new,
6628                                           &group_cnt, &worker_cnt_per_group,
6629                                           &new_groups);
6630                 if (!err) {
6631                         spin_lock_irq(&conf->device_lock);
6632                         conf->group_cnt = group_cnt;
6633                         conf->worker_cnt_per_group = worker_cnt_per_group;
6634                         conf->worker_groups = new_groups;
6635                         spin_unlock_irq(&conf->device_lock);
6636
6637                         if (old_groups)
6638                                 kfree(old_groups[0].workers);
6639                         kfree(old_groups);
6640                 }
6641                 mddev_resume(mddev);
6642         }
6643         mddev_unlock(mddev);
6644
6645         return err ?: len;
6646 }
6647
6648 static struct md_sysfs_entry
6649 raid5_group_thread_cnt = __ATTR(group_thread_cnt, S_IRUGO | S_IWUSR,
6650                                 raid5_show_group_thread_cnt,
6651                                 raid5_store_group_thread_cnt);
6652
6653 static struct attribute *raid5_attrs[] =  {
6654         &raid5_stripecache_size.attr,
6655         &raid5_stripecache_active.attr,
6656         &raid5_preread_bypass_threshold.attr,
6657         &raid5_group_thread_cnt.attr,
6658         &raid5_skip_copy.attr,
6659         &raid5_rmw_level.attr,
6660         &r5c_journal_mode.attr,
6661         NULL,
6662 };
6663 static struct attribute_group raid5_attrs_group = {
6664         .name = NULL,
6665         .attrs = raid5_attrs,
6666 };
6667
6668 static int alloc_thread_groups(struct r5conf *conf, int cnt,
6669                                int *group_cnt,
6670                                int *worker_cnt_per_group,
6671                                struct r5worker_group **worker_groups)
6672 {
6673         int i, j, k;
6674         ssize_t size;
6675         struct r5worker *workers;
6676
6677         *worker_cnt_per_group = cnt;
6678         if (cnt == 0) {
6679                 *group_cnt = 0;
6680                 *worker_groups = NULL;
6681                 return 0;
6682         }
6683         *group_cnt = num_possible_nodes();
6684         size = sizeof(struct r5worker) * cnt;
6685         workers = kzalloc(size * *group_cnt, GFP_NOIO);
6686         *worker_groups = kzalloc(sizeof(struct r5worker_group) *
6687                                 *group_cnt, GFP_NOIO);
6688         if (!*worker_groups || !workers) {
6689                 kfree(workers);
6690                 kfree(*worker_groups);
6691                 return -ENOMEM;
6692         }
6693
6694         for (i = 0; i < *group_cnt; i++) {
6695                 struct r5worker_group *group;
6696
6697                 group = &(*worker_groups)[i];
6698                 INIT_LIST_HEAD(&group->handle_list);
6699                 INIT_LIST_HEAD(&group->loprio_list);
6700                 group->conf = conf;
6701                 group->workers = workers + i * cnt;
6702
6703                 for (j = 0; j < cnt; j++) {
6704                         struct r5worker *worker = group->workers + j;
6705                         worker->group = group;
6706                         INIT_WORK(&worker->work, raid5_do_work);
6707
6708                         for (k = 0; k < NR_STRIPE_HASH_LOCKS; k++)
6709                                 INIT_LIST_HEAD(worker->temp_inactive_list + k);
6710                 }
6711         }
6712
6713         return 0;
6714 }
6715
6716 static void free_thread_groups(struct r5conf *conf)
6717 {
6718         if (conf->worker_groups)
6719                 kfree(conf->worker_groups[0].workers);
6720         kfree(conf->worker_groups);
6721         conf->worker_groups = NULL;
6722 }
6723
6724 static sector_t
6725 raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
6726 {
6727         struct r5conf *conf = mddev->private;
6728
6729         if (!sectors)
6730                 sectors = mddev->dev_sectors;
6731         if (!raid_disks)
6732                 /* size is defined by the smallest of previous and new size */
6733                 raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
6734
6735         sectors &= ~((sector_t)conf->chunk_sectors - 1);
6736         sectors &= ~((sector_t)conf->prev_chunk_sectors - 1);
6737         return sectors * (raid_disks - conf->max_degraded);
6738 }
6739
6740 static void free_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6741 {
6742         safe_put_page(percpu->spare_page);
6743         if (percpu->scribble)
6744                 flex_array_free(percpu->scribble);
6745         percpu->spare_page = NULL;
6746         percpu->scribble = NULL;
6747 }
6748
6749 static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6750 {
6751         if (conf->level == 6 && !percpu->spare_page)
6752                 percpu->spare_page = alloc_page(GFP_KERNEL);
6753         if (!percpu->scribble)
6754                 percpu->scribble = scribble_alloc(max(conf->raid_disks,
6755                                                       conf->previous_raid_disks),
6756                                                   max(conf->chunk_sectors,
6757                                                       conf->prev_chunk_sectors)
6758                                                    / STRIPE_SECTORS,
6759                                                   GFP_KERNEL);
6760
6761         if (!percpu->scribble || (conf->level == 6 && !percpu->spare_page)) {
6762                 free_scratch_buffer(conf, percpu);
6763                 return -ENOMEM;
6764         }
6765
6766         return 0;
6767 }
6768
6769 static int raid456_cpu_dead(unsigned int cpu, struct hlist_node *node)
6770 {
6771         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
6772
6773         free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));
6774         return 0;
6775 }
6776
6777 static void raid5_free_percpu(struct r5conf *conf)
6778 {
6779         if (!conf->percpu)
6780                 return;
6781
6782         cpuhp_state_remove_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
6783         free_percpu(conf->percpu);
6784 }
6785
6786 static void free_conf(struct r5conf *conf)
6787 {
6788         int i;
6789
6790         log_exit(conf);
6791
6792         if (conf->shrinker.nr_deferred)
6793                 unregister_shrinker(&conf->shrinker);
6794
6795         free_thread_groups(conf);
6796         shrink_stripes(conf);
6797         raid5_free_percpu(conf);
6798         for (i = 0; i < conf->pool_size; i++)
6799                 if (conf->disks[i].extra_page)
6800                         put_page(conf->disks[i].extra_page);
6801         kfree(conf->disks);
6802         kfree(conf->stripe_hashtbl);
6803         kfree(conf->pending_data);
6804         kfree(conf);
6805 }
6806
6807 static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
6808 {
6809         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
6810         struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);
6811
6812         if (alloc_scratch_buffer(conf, percpu)) {
6813                 pr_warn("%s: failed memory allocation for cpu%u\n",
6814                         __func__, cpu);
6815                 return -ENOMEM;
6816         }
6817         return 0;
6818 }
6819
6820 static int raid5_alloc_percpu(struct r5conf *conf)
6821 {
6822         int err = 0;
6823
6824         conf->percpu = alloc_percpu(struct raid5_percpu);
6825         if (!conf->percpu)
6826                 return -ENOMEM;
6827
6828         err = cpuhp_state_add_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
6829         if (!err) {
6830                 conf->scribble_disks = max(conf->raid_disks,
6831                         conf->previous_raid_disks);
6832                 conf->scribble_sectors = max(conf->chunk_sectors,
6833                         conf->prev_chunk_sectors);
6834         }
6835         return err;
6836 }
6837
6838 static unsigned long raid5_cache_scan(struct shrinker *shrink,
6839                                       struct shrink_control *sc)
6840 {
6841         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6842         unsigned long ret = SHRINK_STOP;
6843
6844         if (mutex_trylock(&conf->cache_size_mutex)) {
6845                 ret= 0;
6846                 while (ret < sc->nr_to_scan &&
6847                        conf->max_nr_stripes > conf->min_nr_stripes) {
6848                         if (drop_one_stripe(conf) == 0) {
6849                                 ret = SHRINK_STOP;
6850                                 break;
6851                         }
6852                         ret++;
6853                 }
6854                 mutex_unlock(&conf->cache_size_mutex);
6855         }
6856         return ret;
6857 }
6858
6859 static unsigned long raid5_cache_count(struct shrinker *shrink,
6860                                        struct shrink_control *sc)
6861 {
6862         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6863
6864         if (conf->max_nr_stripes < conf->min_nr_stripes)
6865                 /* unlikely, but not impossible */
6866                 return 0;
6867         return conf->max_nr_stripes - conf->min_nr_stripes;
6868 }
6869
6870 static struct r5conf *setup_conf(struct mddev *mddev)
6871 {
6872         struct r5conf *conf;
6873         int raid_disk, memory, max_disks;
6874         struct md_rdev *rdev;
6875         struct disk_info *disk;
6876         char pers_name[6];
6877         int i;
6878         int group_cnt, worker_cnt_per_group;
6879         struct r5worker_group *new_group;
6880
6881         if (mddev->new_level != 5
6882             && mddev->new_level != 4
6883             && mddev->new_level != 6) {
6884                 pr_warn("md/raid:%s: raid level not set to 4/5/6 (%d)\n",
6885                         mdname(mddev), mddev->new_level);
6886                 return ERR_PTR(-EIO);
6887         }
6888         if ((mddev->new_level == 5
6889              && !algorithm_valid_raid5(mddev->new_layout)) ||
6890             (mddev->new_level == 6
6891              && !algorithm_valid_raid6(mddev->new_layout))) {
6892                 pr_warn("md/raid:%s: layout %d not supported\n",
6893                         mdname(mddev), mddev->new_layout);
6894                 return ERR_PTR(-EIO);
6895         }
6896         if (mddev->new_level == 6 && mddev->raid_disks < 4) {
6897                 pr_warn("md/raid:%s: not enough configured devices (%d, minimum 4)\n",
6898                         mdname(mddev), mddev->raid_disks);
6899                 return ERR_PTR(-EINVAL);
6900         }
6901
6902         if (!mddev->new_chunk_sectors ||
6903             (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
6904             !is_power_of_2(mddev->new_chunk_sectors)) {
6905                 pr_warn("md/raid:%s: invalid chunk size %d\n",
6906                         mdname(mddev), mddev->new_chunk_sectors << 9);
6907                 return ERR_PTR(-EINVAL);
6908         }
6909
6910         conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
6911         if (conf == NULL)
6912                 goto abort;
6913         INIT_LIST_HEAD(&conf->free_list);
6914         INIT_LIST_HEAD(&conf->pending_list);
6915         conf->pending_data = kzalloc(sizeof(struct r5pending_data) *
6916                 PENDING_IO_MAX, GFP_KERNEL);
6917         if (!conf->pending_data)
6918                 goto abort;
6919         for (i = 0; i < PENDING_IO_MAX; i++)
6920                 list_add(&conf->pending_data[i].sibling, &conf->free_list);
6921         /* Don't enable multi-threading by default*/
6922         if (!alloc_thread_groups(conf, 0, &group_cnt, &worker_cnt_per_group,
6923                                  &new_group)) {
6924                 conf->group_cnt = group_cnt;
6925                 conf->worker_cnt_per_group = worker_cnt_per_group;
6926                 conf->worker_groups = new_group;
6927         } else
6928                 goto abort;
6929         spin_lock_init(&conf->device_lock);
6930         seqcount_init(&conf->gen_lock);
6931         mutex_init(&conf->cache_size_mutex);
6932         init_waitqueue_head(&conf->wait_for_quiescent);
6933         init_waitqueue_head(&conf->wait_for_stripe);
6934         init_waitqueue_head(&conf->wait_for_overlap);
6935         INIT_LIST_HEAD(&conf->handle_list);
6936         INIT_LIST_HEAD(&conf->loprio_list);
6937         INIT_LIST_HEAD(&conf->hold_list);
6938         INIT_LIST_HEAD(&conf->delayed_list);
6939         INIT_LIST_HEAD(&conf->bitmap_list);
6940         bio_list_init(&conf->return_bi);
6941         init_llist_head(&conf->released_stripes);
6942         atomic_set(&conf->active_stripes, 0);
6943         atomic_set(&conf->preread_active_stripes, 0);
6944         atomic_set(&conf->active_aligned_reads, 0);
6945         spin_lock_init(&conf->pending_bios_lock);
6946         conf->batch_bio_dispatch = true;
6947         rdev_for_each(rdev, mddev) {
6948                 if (test_bit(Journal, &rdev->flags))
6949                         continue;
6950                 if (blk_queue_nonrot(bdev_get_queue(rdev->bdev))) {
6951                         conf->batch_bio_dispatch = false;
6952                         break;
6953                 }
6954         }
6955
6956         conf->bypass_threshold = BYPASS_THRESHOLD;
6957         conf->recovery_disabled = mddev->recovery_disabled - 1;
6958
6959         conf->raid_disks = mddev->raid_disks;
6960         if (mddev->reshape_position == MaxSector)
6961                 conf->previous_raid_disks = mddev->raid_disks;
6962         else
6963                 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
6964         max_disks = max(conf->raid_disks, conf->previous_raid_disks);
6965
6966         conf->disks = kzalloc(max_disks * sizeof(struct disk_info),
6967                               GFP_KERNEL);
6968
6969         if (!conf->disks)
6970                 goto abort;
6971
6972         for (i = 0; i < max_disks; i++) {
6973                 conf->disks[i].extra_page = alloc_page(GFP_KERNEL);
6974                 if (!conf->disks[i].extra_page)
6975                         goto abort;
6976         }
6977
6978         conf->mddev = mddev;
6979
6980         if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
6981                 goto abort;
6982
6983         /* We init hash_locks[0] separately to that it can be used
6984          * as the reference lock in the spin_lock_nest_lock() call
6985          * in lock_all_device_hash_locks_irq in order to convince
6986          * lockdep that we know what we are doing.
6987          */
6988         spin_lock_init(conf->hash_locks);
6989         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
6990                 spin_lock_init(conf->hash_locks + i);
6991
6992         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6993                 INIT_LIST_HEAD(conf->inactive_list + i);
6994
6995         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6996                 INIT_LIST_HEAD(conf->temp_inactive_list + i);
6997
6998         atomic_set(&conf->r5c_cached_full_stripes, 0);
6999         INIT_LIST_HEAD(&conf->r5c_full_stripe_list);
7000         atomic_set(&conf->r5c_cached_partial_stripes, 0);
7001         INIT_LIST_HEAD(&conf->r5c_partial_stripe_list);
7002         atomic_set(&conf->r5c_flushing_full_stripes, 0);
7003         atomic_set(&conf->r5c_flushing_partial_stripes, 0);
7004
7005         conf->level = mddev->new_level;
7006         conf->chunk_sectors = mddev->new_chunk_sectors;
7007         if (raid5_alloc_percpu(conf) != 0)
7008                 goto abort;
7009
7010         pr_debug("raid456: run(%s) called.\n", mdname(mddev));
7011
7012         rdev_for_each(rdev, mddev) {
7013                 raid_disk = rdev->raid_disk;
7014                 if (raid_disk >= max_disks
7015                     || raid_disk < 0 || test_bit(Journal, &rdev->flags))
7016                         continue;
7017                 disk = conf->disks + raid_disk;
7018
7019                 if (test_bit(Replacement, &rdev->flags)) {
7020                         if (disk->replacement)
7021                                 goto abort;
7022                         disk->replacement = rdev;
7023                 } else {
7024                         if (disk->rdev)
7025                                 goto abort;
7026                         disk->rdev = rdev;
7027                 }
7028
7029                 if (test_bit(In_sync, &rdev->flags)) {
7030                         char b[BDEVNAME_SIZE];
7031                         pr_info("md/raid:%s: device %s operational as raid disk %d\n",
7032                                 mdname(mddev), bdevname(rdev->bdev, b), raid_disk);
7033                 } else if (rdev->saved_raid_disk != raid_disk)
7034                         /* Cannot rely on bitmap to complete recovery */
7035                         conf->fullsync = 1;
7036         }
7037
7038         conf->level = mddev->new_level;
7039         if (conf->level == 6) {
7040                 conf->max_degraded = 2;
7041                 if (raid6_call.xor_syndrome)
7042                         conf->rmw_level = PARITY_ENABLE_RMW;
7043                 else
7044                         conf->rmw_level = PARITY_DISABLE_RMW;
7045         } else {
7046                 conf->max_degraded = 1;
7047                 conf->rmw_level = PARITY_ENABLE_RMW;
7048         }
7049         conf->algorithm = mddev->new_layout;
7050         conf->reshape_progress = mddev->reshape_position;
7051         if (conf->reshape_progress != MaxSector) {
7052                 conf->prev_chunk_sectors = mddev->chunk_sectors;
7053                 conf->prev_algo = mddev->layout;
7054         } else {
7055                 conf->prev_chunk_sectors = conf->chunk_sectors;
7056                 conf->prev_algo = conf->algorithm;
7057         }
7058
7059         conf->min_nr_stripes = NR_STRIPES;
7060         if (mddev->reshape_position != MaxSector) {
7061                 int stripes = max_t(int,
7062                         ((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4,
7063                         ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4);
7064                 conf->min_nr_stripes = max(NR_STRIPES, stripes);
7065                 if (conf->min_nr_stripes != NR_STRIPES)
7066                         pr_info("md/raid:%s: force stripe size %d for reshape\n",
7067                                 mdname(mddev), conf->min_nr_stripes);
7068         }
7069         memory = conf->min_nr_stripes * (sizeof(struct stripe_head) +
7070                  max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
7071         atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS);
7072         if (grow_stripes(conf, conf->min_nr_stripes)) {
7073                 pr_warn("md/raid:%s: couldn't allocate %dkB for buffers\n",
7074                         mdname(mddev), memory);
7075                 goto abort;
7076         } else
7077                 pr_debug("md/raid:%s: allocated %dkB\n", mdname(mddev), memory);
7078         /*
7079          * Losing a stripe head costs more than the time to refill it,
7080          * it reduces the queue depth and so can hurt throughput.
7081          * So set it rather large, scaled by number of devices.
7082          */
7083         conf->shrinker.seeks = DEFAULT_SEEKS * conf->raid_disks * 4;
7084         conf->shrinker.scan_objects = raid5_cache_scan;
7085         conf->shrinker.count_objects = raid5_cache_count;
7086         conf->shrinker.batch = 128;
7087         conf->shrinker.flags = 0;
7088         if (register_shrinker(&conf->shrinker)) {
7089                 pr_warn("md/raid:%s: couldn't register shrinker.\n",
7090                         mdname(mddev));
7091                 goto abort;
7092         }
7093
7094         sprintf(pers_name, "raid%d", mddev->new_level);
7095         conf->thread = md_register_thread(raid5d, mddev, pers_name);
7096         if (!conf->thread) {
7097                 pr_warn("md/raid:%s: couldn't allocate thread.\n",
7098                         mdname(mddev));
7099                 goto abort;
7100         }
7101
7102         return conf;
7103
7104  abort:
7105         if (conf) {
7106                 free_conf(conf);
7107                 return ERR_PTR(-EIO);
7108         } else
7109                 return ERR_PTR(-ENOMEM);
7110 }
7111
7112 static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
7113 {
7114         switch (algo) {
7115         case ALGORITHM_PARITY_0:
7116                 if (raid_disk < max_degraded)
7117                         return 1;
7118                 break;
7119         case ALGORITHM_PARITY_N:
7120                 if (raid_disk >= raid_disks - max_degraded)
7121                         return 1;
7122                 break;
7123         case ALGORITHM_PARITY_0_6:
7124                 if (raid_disk == 0 ||
7125                     raid_disk == raid_disks - 1)
7126                         return 1;
7127                 break;
7128         case ALGORITHM_LEFT_ASYMMETRIC_6:
7129         case ALGORITHM_RIGHT_ASYMMETRIC_6:
7130         case ALGORITHM_LEFT_SYMMETRIC_6:
7131         case ALGORITHM_RIGHT_SYMMETRIC_6:
7132                 if (raid_disk == raid_disks - 1)
7133                         return 1;
7134         }
7135         return 0;
7136 }
7137
7138 static int raid5_run(struct mddev *mddev)
7139 {
7140         struct r5conf *conf;
7141         int working_disks = 0;
7142         int dirty_parity_disks = 0;
7143         struct md_rdev *rdev;
7144         struct md_rdev *journal_dev = NULL;
7145         sector_t reshape_offset = 0;
7146         int i;
7147         long long min_offset_diff = 0;
7148         int first = 1;
7149
7150         if (mddev->recovery_cp != MaxSector)
7151                 pr_notice("md/raid:%s: not clean -- starting background reconstruction\n",
7152                           mdname(mddev));
7153
7154         rdev_for_each(rdev, mddev) {
7155                 long long diff;
7156
7157                 if (test_bit(Journal, &rdev->flags)) {
7158                         journal_dev = rdev;
7159                         continue;
7160                 }
7161                 if (rdev->raid_disk < 0)
7162                         continue;
7163                 diff = (rdev->new_data_offset - rdev->data_offset);
7164                 if (first) {
7165                         min_offset_diff = diff;
7166                         first = 0;
7167                 } else if (mddev->reshape_backwards &&
7168                          diff < min_offset_diff)
7169                         min_offset_diff = diff;
7170                 else if (!mddev->reshape_backwards &&
7171                          diff > min_offset_diff)
7172                         min_offset_diff = diff;
7173         }
7174
7175         if (mddev->reshape_position != MaxSector) {
7176                 /* Check that we can continue the reshape.
7177                  * Difficulties arise if the stripe we would write to
7178                  * next is at or after the stripe we would read from next.
7179                  * For a reshape that changes the number of devices, this
7180                  * is only possible for a very short time, and mdadm makes
7181                  * sure that time appears to have past before assembling
7182                  * the array.  So we fail if that time hasn't passed.
7183                  * For a reshape that keeps the number of devices the same
7184                  * mdadm must be monitoring the reshape can keeping the
7185                  * critical areas read-only and backed up.  It will start
7186                  * the array in read-only mode, so we check for that.
7187                  */
7188                 sector_t here_new, here_old;
7189                 int old_disks;
7190                 int max_degraded = (mddev->level == 6 ? 2 : 1);
7191                 int chunk_sectors;
7192                 int new_data_disks;
7193
7194                 if (journal_dev) {
7195                         pr_warn("md/raid:%s: don't support reshape with journal - aborting.\n",
7196                                 mdname(mddev));
7197                         return -EINVAL;
7198                 }
7199
7200                 if (mddev->new_level != mddev->level) {
7201                         pr_warn("md/raid:%s: unsupported reshape required - aborting.\n",
7202                                 mdname(mddev));
7203                         return -EINVAL;
7204                 }
7205                 old_disks = mddev->raid_disks - mddev->delta_disks;
7206                 /* reshape_position must be on a new-stripe boundary, and one
7207                  * further up in new geometry must map after here in old
7208                  * geometry.
7209                  * If the chunk sizes are different, then as we perform reshape
7210                  * in units of the largest of the two, reshape_position needs
7211                  * be a multiple of the largest chunk size times new data disks.
7212                  */
7213                 here_new = mddev->reshape_position;
7214                 chunk_sectors = max(mddev->chunk_sectors, mddev->new_chunk_sectors);
7215                 new_data_disks = mddev->raid_disks - max_degraded;
7216                 if (sector_div(here_new, chunk_sectors * new_data_disks)) {
7217                         pr_warn("md/raid:%s: reshape_position not on a stripe boundary\n",
7218                                 mdname(mddev));
7219                         return -EINVAL;
7220                 }
7221                 reshape_offset = here_new * chunk_sectors;
7222                 /* here_new is the stripe we will write to */
7223                 here_old = mddev->reshape_position;
7224                 sector_div(here_old, chunk_sectors * (old_disks-max_degraded));
7225                 /* here_old is the first stripe that we might need to read
7226                  * from */
7227                 if (mddev->delta_disks == 0) {
7228                         /* We cannot be sure it is safe to start an in-place
7229                          * reshape.  It is only safe if user-space is monitoring
7230                          * and taking constant backups.
7231                          * mdadm always starts a situation like this in
7232                          * readonly mode so it can take control before
7233                          * allowing any writes.  So just check for that.
7234                          */
7235                         if (abs(min_offset_diff) >= mddev->chunk_sectors &&
7236                             abs(min_offset_diff) >= mddev->new_chunk_sectors)
7237                                 /* not really in-place - so OK */;
7238                         else if (mddev->ro == 0) {
7239                                 pr_warn("md/raid:%s: in-place reshape must be started in read-only mode - aborting\n",
7240                                         mdname(mddev));
7241                                 return -EINVAL;
7242                         }
7243                 } else if (mddev->reshape_backwards
7244                     ? (here_new * chunk_sectors + min_offset_diff <=
7245                        here_old * chunk_sectors)
7246                     : (here_new * chunk_sectors >=
7247                        here_old * chunk_sectors + (-min_offset_diff))) {
7248                         /* Reading from the same stripe as writing to - bad */
7249                         pr_warn("md/raid:%s: reshape_position too early for auto-recovery - aborting.\n",
7250                                 mdname(mddev));
7251                         return -EINVAL;
7252                 }
7253                 pr_debug("md/raid:%s: reshape will continue\n", mdname(mddev));
7254                 /* OK, we should be able to continue; */
7255         } else {
7256                 BUG_ON(mddev->level != mddev->new_level);
7257                 BUG_ON(mddev->layout != mddev->new_layout);
7258                 BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
7259                 BUG_ON(mddev->delta_disks != 0);
7260         }
7261
7262         if (test_bit(MD_HAS_JOURNAL, &mddev->flags) &&
7263             test_bit(MD_HAS_PPL, &mddev->flags)) {
7264                 pr_warn("md/raid:%s: using journal device and PPL not allowed - disabling PPL\n",
7265                         mdname(mddev));
7266                 clear_bit(MD_HAS_PPL, &mddev->flags);
7267         }
7268
7269         if (mddev->private == NULL)
7270                 conf = setup_conf(mddev);
7271         else
7272                 conf = mddev->private;
7273
7274         if (IS_ERR(conf))
7275                 return PTR_ERR(conf);
7276
7277         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
7278                 if (!journal_dev) {
7279                         pr_warn("md/raid:%s: journal disk is missing, force array readonly\n",
7280                                 mdname(mddev));
7281                         mddev->ro = 1;
7282                         set_disk_ro(mddev->gendisk, 1);
7283                 } else if (mddev->recovery_cp == MaxSector)
7284                         set_bit(MD_JOURNAL_CLEAN, &mddev->flags);
7285         }
7286
7287         conf->min_offset_diff = min_offset_diff;
7288         mddev->thread = conf->thread;
7289         conf->thread = NULL;
7290         mddev->private = conf;
7291
7292         for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
7293              i++) {
7294                 rdev = conf->disks[i].rdev;
7295                 if (!rdev && conf->disks[i].replacement) {
7296                         /* The replacement is all we have yet */
7297                         rdev = conf->disks[i].replacement;
7298                         conf->disks[i].replacement = NULL;
7299                         clear_bit(Replacement, &rdev->flags);
7300                         conf->disks[i].rdev = rdev;
7301                 }
7302                 if (!rdev)
7303                         continue;
7304                 if (conf->disks[i].replacement &&
7305                     conf->reshape_progress != MaxSector) {
7306                         /* replacements and reshape simply do not mix. */
7307                         pr_warn("md: cannot handle concurrent replacement and reshape.\n");
7308                         goto abort;
7309                 }
7310                 if (test_bit(In_sync, &rdev->flags)) {
7311                         working_disks++;
7312                         continue;
7313                 }
7314                 /* This disc is not fully in-sync.  However if it
7315                  * just stored parity (beyond the recovery_offset),
7316                  * when we don't need to be concerned about the
7317                  * array being dirty.
7318                  * When reshape goes 'backwards', we never have
7319                  * partially completed devices, so we only need
7320                  * to worry about reshape going forwards.
7321                  */
7322                 /* Hack because v0.91 doesn't store recovery_offset properly. */
7323                 if (mddev->major_version == 0 &&
7324                     mddev->minor_version > 90)
7325                         rdev->recovery_offset = reshape_offset;
7326
7327                 if (rdev->recovery_offset < reshape_offset) {
7328                         /* We need to check old and new layout */
7329                         if (!only_parity(rdev->raid_disk,
7330                                          conf->algorithm,
7331                                          conf->raid_disks,
7332                                          conf->max_degraded))
7333                                 continue;
7334                 }
7335                 if (!only_parity(rdev->raid_disk,
7336                                  conf->prev_algo,
7337                                  conf->previous_raid_disks,
7338                                  conf->max_degraded))
7339                         continue;
7340                 dirty_parity_disks++;
7341         }
7342
7343         /*
7344          * 0 for a fully functional array, 1 or 2 for a degraded array.
7345          */
7346         mddev->degraded = raid5_calc_degraded(conf);
7347
7348         if (has_failed(conf)) {
7349                 pr_crit("md/raid:%s: not enough operational devices (%d/%d failed)\n",
7350                         mdname(mddev), mddev->degraded, conf->raid_disks);
7351                 goto abort;
7352         }
7353
7354         /* device size must be a multiple of chunk size */
7355         mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
7356         mddev->resync_max_sectors = mddev->dev_sectors;
7357
7358         if (mddev->degraded > dirty_parity_disks &&
7359             mddev->recovery_cp != MaxSector) {
7360                 if (test_bit(MD_HAS_PPL, &mddev->flags))
7361                         pr_crit("md/raid:%s: starting dirty degraded array with PPL.\n",
7362                                 mdname(mddev));
7363                 else if (mddev->ok_start_degraded)
7364                         pr_crit("md/raid:%s: starting dirty degraded array - data corruption possible.\n",
7365                                 mdname(mddev));
7366                 else {
7367                         pr_crit("md/raid:%s: cannot start dirty degraded array.\n",
7368                                 mdname(mddev));
7369                         goto abort;
7370                 }
7371         }
7372
7373         pr_info("md/raid:%s: raid level %d active with %d out of %d devices, algorithm %d\n",
7374                 mdname(mddev), conf->level,
7375                 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
7376                 mddev->new_layout);
7377
7378         print_raid5_conf(conf);
7379
7380         if (conf->reshape_progress != MaxSector) {
7381                 conf->reshape_safe = conf->reshape_progress;
7382                 atomic_set(&conf->reshape_stripes, 0);
7383                 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7384                 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7385                 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7386                 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7387                 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7388                                                         "reshape");
7389         }
7390
7391         /* Ok, everything is just fine now */
7392         if (mddev->to_remove == &raid5_attrs_group)
7393                 mddev->to_remove = NULL;
7394         else if (mddev->kobj.sd &&
7395             sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
7396                 pr_warn("raid5: failed to create sysfs attributes for %s\n",
7397                         mdname(mddev));
7398         md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
7399
7400         if (mddev->queue) {
7401                 int chunk_size;
7402                 bool discard_supported = true;
7403                 /* read-ahead size must cover two whole stripes, which
7404                  * is 2 * (datadisks) * chunksize where 'n' is the
7405                  * number of raid devices
7406                  */
7407                 int data_disks = conf->previous_raid_disks - conf->max_degraded;
7408                 int stripe = data_disks *
7409                         ((mddev->chunk_sectors << 9) / PAGE_SIZE);
7410                 if (mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
7411                         mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
7412
7413                 chunk_size = mddev->chunk_sectors << 9;
7414                 blk_queue_io_min(mddev->queue, chunk_size);
7415                 blk_queue_io_opt(mddev->queue, chunk_size *
7416                                  (conf->raid_disks - conf->max_degraded));
7417                 mddev->queue->limits.raid_partial_stripes_expensive = 1;
7418                 /*
7419                  * We can only discard a whole stripe. It doesn't make sense to
7420                  * discard data disk but write parity disk
7421                  */
7422                 stripe = stripe * PAGE_SIZE;
7423                 /* Round up to power of 2, as discard handling
7424                  * currently assumes that */
7425                 while ((stripe-1) & stripe)
7426                         stripe = (stripe | (stripe-1)) + 1;
7427                 mddev->queue->limits.discard_alignment = stripe;
7428                 mddev->queue->limits.discard_granularity = stripe;
7429
7430                 /*
7431                  * We use 16-bit counter of active stripes in bi_phys_segments
7432                  * (minus one for over-loaded initialization)
7433                  */
7434                 blk_queue_max_hw_sectors(mddev->queue, 0xfffe * STRIPE_SECTORS);
7435                 blk_queue_max_discard_sectors(mddev->queue,
7436                                               0xfffe * STRIPE_SECTORS);
7437
7438                 /*
7439                  * unaligned part of discard request will be ignored, so can't
7440                  * guarantee discard_zeroes_data
7441                  */
7442                 mddev->queue->limits.discard_zeroes_data = 0;
7443
7444                 blk_queue_max_write_same_sectors(mddev->queue, 0);
7445
7446                 rdev_for_each(rdev, mddev) {
7447                         disk_stack_limits(mddev->gendisk, rdev->bdev,
7448                                           rdev->data_offset << 9);
7449                         disk_stack_limits(mddev->gendisk, rdev->bdev,
7450                                           rdev->new_data_offset << 9);
7451                         /*
7452                          * discard_zeroes_data is required, otherwise data
7453                          * could be lost. Consider a scenario: discard a stripe
7454                          * (the stripe could be inconsistent if
7455                          * discard_zeroes_data is 0); write one disk of the
7456                          * stripe (the stripe could be inconsistent again
7457                          * depending on which disks are used to calculate
7458                          * parity); the disk is broken; The stripe data of this
7459                          * disk is lost.
7460                          */
7461                         if (!blk_queue_discard(bdev_get_queue(rdev->bdev)) ||
7462                             !bdev_get_queue(rdev->bdev)->
7463                                                 limits.discard_zeroes_data)
7464                                 discard_supported = false;
7465                         /* Unfortunately, discard_zeroes_data is not currently
7466                          * a guarantee - just a hint.  So we only allow DISCARD
7467                          * if the sysadmin has confirmed that only safe devices
7468                          * are in use by setting a module parameter.
7469                          */
7470                         if (!devices_handle_discard_safely) {
7471                                 if (discard_supported) {
7472                                         pr_info("md/raid456: discard support disabled due to uncertainty.\n");
7473                                         pr_info("Set raid456.devices_handle_discard_safely=Y to override.\n");
7474                                 }
7475                                 discard_supported = false;
7476                         }
7477                 }
7478
7479                 if (discard_supported &&
7480                     mddev->queue->limits.max_discard_sectors >= (stripe >> 9) &&
7481                     mddev->queue->limits.discard_granularity >= stripe)
7482                         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
7483                                                 mddev->queue);
7484                 else
7485                         queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
7486                                                 mddev->queue);
7487
7488                 blk_queue_max_hw_sectors(mddev->queue, UINT_MAX);
7489         }
7490
7491         if (log_init(conf, journal_dev))
7492                 goto abort;
7493
7494         return 0;
7495 abort:
7496         md_unregister_thread(&mddev->thread);
7497         print_raid5_conf(conf);
7498         free_conf(conf);
7499         mddev->private = NULL;
7500         pr_warn("md/raid:%s: failed to run raid set.\n", mdname(mddev));
7501         return -EIO;
7502 }
7503
7504 static void raid5_free(struct mddev *mddev, void *priv)
7505 {
7506         struct r5conf *conf = priv;
7507
7508         free_conf(conf);
7509         mddev->to_remove = &raid5_attrs_group;
7510 }
7511
7512 static void raid5_status(struct seq_file *seq, struct mddev *mddev)
7513 {
7514         struct r5conf *conf = mddev->private;
7515         int i;
7516
7517         seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
7518                 conf->chunk_sectors / 2, mddev->layout);
7519         seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
7520         rcu_read_lock();
7521         for (i = 0; i < conf->raid_disks; i++) {
7522                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
7523                 seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
7524         }
7525         rcu_read_unlock();
7526         seq_printf (seq, "]");
7527 }
7528
7529 static void print_raid5_conf (struct r5conf *conf)
7530 {
7531         int i;
7532         struct disk_info *tmp;
7533
7534         pr_debug("RAID conf printout:\n");
7535         if (!conf) {
7536                 pr_debug("(conf==NULL)\n");
7537                 return;
7538         }
7539         pr_debug(" --- level:%d rd:%d wd:%d\n", conf->level,
7540                conf->raid_disks,
7541                conf->raid_disks - conf->mddev->degraded);
7542
7543         for (i = 0; i < conf->raid_disks; i++) {
7544                 char b[BDEVNAME_SIZE];
7545                 tmp = conf->disks + i;
7546                 if (tmp->rdev)
7547                         pr_debug(" disk %d, o:%d, dev:%s\n",
7548                                i, !test_bit(Faulty, &tmp->rdev->flags),
7549                                bdevname(tmp->rdev->bdev, b));
7550         }
7551 }
7552
7553 static int raid5_spare_active(struct mddev *mddev)
7554 {
7555         int i;
7556         struct r5conf *conf = mddev->private;
7557         struct disk_info *tmp;
7558         int count = 0;
7559         unsigned long flags;
7560
7561         for (i = 0; i < conf->raid_disks; i++) {
7562                 tmp = conf->disks + i;
7563                 if (tmp->replacement
7564                     && tmp->replacement->recovery_offset == MaxSector
7565                     && !test_bit(Faulty, &tmp->replacement->flags)
7566                     && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
7567                         /* Replacement has just become active. */
7568                         if (!tmp->rdev
7569                             || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
7570                                 count++;
7571                         if (tmp->rdev) {
7572                                 /* Replaced device not technically faulty,
7573                                  * but we need to be sure it gets removed
7574                                  * and never re-added.
7575                                  */
7576                                 set_bit(Faulty, &tmp->rdev->flags);
7577                                 sysfs_notify_dirent_safe(
7578                                         tmp->rdev->sysfs_state);
7579                         }
7580                         sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
7581                 } else if (tmp->rdev
7582                     && tmp->rdev->recovery_offset == MaxSector
7583                     && !test_bit(Faulty, &tmp->rdev->flags)
7584                     && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
7585                         count++;
7586                         sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
7587                 }
7588         }
7589         spin_lock_irqsave(&conf->device_lock, flags);
7590         mddev->degraded = raid5_calc_degraded(conf);
7591         spin_unlock_irqrestore(&conf->device_lock, flags);
7592         print_raid5_conf(conf);
7593         return count;
7594 }
7595
7596 static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
7597 {
7598         struct r5conf *conf = mddev->private;
7599         int err = 0;
7600         int number = rdev->raid_disk;
7601         struct md_rdev **rdevp;
7602         struct disk_info *p = conf->disks + number;
7603
7604         print_raid5_conf(conf);
7605         if (test_bit(Journal, &rdev->flags) && conf->log) {
7606                 /*
7607                  * we can't wait pending write here, as this is called in
7608                  * raid5d, wait will deadlock.
7609                  */
7610                 if (atomic_read(&mddev->writes_pending))
7611                         return -EBUSY;
7612                 log_exit(conf);
7613                 return 0;
7614         }
7615         if (rdev == p->rdev)
7616                 rdevp = &p->rdev;
7617         else if (rdev == p->replacement)
7618                 rdevp = &p->replacement;
7619         else
7620                 return 0;
7621
7622         if (number >= conf->raid_disks &&
7623             conf->reshape_progress == MaxSector)
7624                 clear_bit(In_sync, &rdev->flags);
7625
7626         if (test_bit(In_sync, &rdev->flags) ||
7627             atomic_read(&rdev->nr_pending)) {
7628                 err = -EBUSY;
7629                 goto abort;
7630         }
7631         /* Only remove non-faulty devices if recovery
7632          * isn't possible.
7633          */
7634         if (!test_bit(Faulty, &rdev->flags) &&
7635             mddev->recovery_disabled != conf->recovery_disabled &&
7636             !has_failed(conf) &&
7637             (!p->replacement || p->replacement == rdev) &&
7638             number < conf->raid_disks) {
7639                 err = -EBUSY;
7640                 goto abort;
7641         }
7642         *rdevp = NULL;
7643         if (!test_bit(RemoveSynchronized, &rdev->flags)) {
7644                 synchronize_rcu();
7645                 if (atomic_read(&rdev->nr_pending)) {
7646                         /* lost the race, try later */
7647                         err = -EBUSY;
7648                         *rdevp = rdev;
7649                 }
7650         }
7651         if (!err) {
7652                 err = log_modify(conf, rdev, false);
7653                 if (err)
7654                         goto abort;
7655         }
7656         if (p->replacement) {
7657                 /* We must have just cleared 'rdev' */
7658                 p->rdev = p->replacement;
7659                 clear_bit(Replacement, &p->replacement->flags);
7660                 smp_mb(); /* Make sure other CPUs may see both as identical
7661                            * but will never see neither - if they are careful
7662                            */
7663                 p->replacement = NULL;
7664                 clear_bit(WantReplacement, &rdev->flags);
7665
7666                 if (!err)
7667                         err = log_modify(conf, p->rdev, true);
7668         } else
7669                 /* We might have just removed the Replacement as faulty-
7670                  * clear the bit just in case
7671                  */
7672                 clear_bit(WantReplacement, &rdev->flags);
7673 abort:
7674
7675         print_raid5_conf(conf);
7676         return err;
7677 }
7678
7679 static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
7680 {
7681         struct r5conf *conf = mddev->private;
7682         int err = -EEXIST;
7683         int disk;
7684         struct disk_info *p;
7685         int first = 0;
7686         int last = conf->raid_disks - 1;
7687
7688         if (test_bit(Journal, &rdev->flags)) {
7689                 if (conf->log)
7690                         return -EBUSY;
7691
7692                 rdev->raid_disk = 0;
7693                 /*
7694                  * The array is in readonly mode if journal is missing, so no
7695                  * write requests running. We should be safe
7696                  */
7697                 log_init(conf, rdev);
7698                 return 0;
7699         }
7700         if (mddev->recovery_disabled == conf->recovery_disabled)
7701                 return -EBUSY;
7702
7703         if (rdev->saved_raid_disk < 0 && has_failed(conf))
7704                 /* no point adding a device */
7705                 return -EINVAL;
7706
7707         if (rdev->raid_disk >= 0)
7708                 first = last = rdev->raid_disk;
7709
7710         /*
7711          * find the disk ... but prefer rdev->saved_raid_disk
7712          * if possible.
7713          */
7714         if (rdev->saved_raid_disk >= 0 &&
7715             rdev->saved_raid_disk >= first &&
7716             conf->disks[rdev->saved_raid_disk].rdev == NULL)
7717                 first = rdev->saved_raid_disk;
7718
7719         for (disk = first; disk <= last; disk++) {
7720                 p = conf->disks + disk;
7721                 if (p->rdev == NULL) {
7722                         clear_bit(In_sync, &rdev->flags);
7723                         rdev->raid_disk = disk;
7724                         if (rdev->saved_raid_disk != disk)
7725                                 conf->fullsync = 1;
7726                         rcu_assign_pointer(p->rdev, rdev);
7727
7728                         err = log_modify(conf, rdev, true);
7729
7730                         goto out;
7731                 }
7732         }
7733         for (disk = first; disk <= last; disk++) {
7734                 p = conf->disks + disk;
7735                 if (test_bit(WantReplacement, &p->rdev->flags) &&
7736                     p->replacement == NULL) {
7737                         clear_bit(In_sync, &rdev->flags);
7738                         set_bit(Replacement, &rdev->flags);
7739                         rdev->raid_disk = disk;
7740                         err = 0;
7741                         conf->fullsync = 1;
7742                         rcu_assign_pointer(p->replacement, rdev);
7743                         break;
7744                 }
7745         }
7746 out:
7747         print_raid5_conf(conf);
7748         return err;
7749 }
7750
7751 static int raid5_resize(struct mddev *mddev, sector_t sectors)
7752 {
7753         /* no resync is happening, and there is enough space
7754          * on all devices, so we can resize.
7755          * We need to make sure resync covers any new space.
7756          * If the array is shrinking we should possibly wait until
7757          * any io in the removed space completes, but it hardly seems
7758          * worth it.
7759          */
7760         sector_t newsize;
7761         struct r5conf *conf = mddev->private;
7762
7763         if (conf->log || raid5_has_ppl(conf))
7764                 return -EINVAL;
7765         sectors &= ~((sector_t)conf->chunk_sectors - 1);
7766         newsize = raid5_size(mddev, sectors, mddev->raid_disks);
7767         if (mddev->external_size &&
7768             mddev->array_sectors > newsize)
7769                 return -EINVAL;
7770         if (mddev->bitmap) {
7771                 int ret = bitmap_resize(mddev->bitmap, sectors, 0, 0);
7772                 if (ret)
7773                         return ret;
7774         }
7775         md_set_array_sectors(mddev, newsize);
7776         if (sectors > mddev->dev_sectors &&
7777             mddev->recovery_cp > mddev->dev_sectors) {
7778                 mddev->recovery_cp = mddev->dev_sectors;
7779                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7780         }
7781         mddev->dev_sectors = sectors;
7782         mddev->resync_max_sectors = sectors;
7783         return 0;
7784 }
7785
7786 static int check_stripe_cache(struct mddev *mddev)
7787 {
7788         /* Can only proceed if there are plenty of stripe_heads.
7789          * We need a minimum of one full stripe,, and for sensible progress
7790          * it is best to have about 4 times that.
7791          * If we require 4 times, then the default 256 4K stripe_heads will
7792          * allow for chunk sizes up to 256K, which is probably OK.
7793          * If the chunk size is greater, user-space should request more
7794          * stripe_heads first.
7795          */
7796         struct r5conf *conf = mddev->private;
7797         if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4
7798             > conf->min_nr_stripes ||
7799             ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4
7800             > conf->min_nr_stripes) {
7801                 pr_warn("md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
7802                         mdname(mddev),
7803                         ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
7804                          / STRIPE_SIZE)*4);
7805                 return 0;
7806         }
7807         return 1;
7808 }
7809
7810 static int check_reshape(struct mddev *mddev)
7811 {
7812         struct r5conf *conf = mddev->private;
7813
7814         if (conf->log || raid5_has_ppl(conf))
7815                 return -EINVAL;
7816         if (mddev->delta_disks == 0 &&
7817             mddev->new_layout == mddev->layout &&
7818             mddev->new_chunk_sectors == mddev->chunk_sectors)
7819                 return 0; /* nothing to do */
7820         if (has_failed(conf))
7821                 return -EINVAL;
7822         if (mddev->delta_disks < 0 && mddev->reshape_position == MaxSector) {
7823                 /* We might be able to shrink, but the devices must
7824                  * be made bigger first.
7825                  * For raid6, 4 is the minimum size.
7826                  * Otherwise 2 is the minimum
7827                  */
7828                 int min = 2;
7829                 if (mddev->level == 6)
7830                         min = 4;
7831                 if (mddev->raid_disks + mddev->delta_disks < min)
7832                         return -EINVAL;
7833         }
7834
7835         if (!check_stripe_cache(mddev))
7836                 return -ENOSPC;
7837
7838         if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
7839             mddev->delta_disks > 0)
7840                 if (resize_chunks(conf,
7841                                   conf->previous_raid_disks
7842                                   + max(0, mddev->delta_disks),
7843                                   max(mddev->new_chunk_sectors,
7844                                       mddev->chunk_sectors)
7845                             ) < 0)
7846                         return -ENOMEM;
7847         return resize_stripes(conf, (conf->previous_raid_disks
7848                                      + mddev->delta_disks));
7849 }
7850
7851 static int raid5_start_reshape(struct mddev *mddev)
7852 {
7853         struct r5conf *conf = mddev->private;
7854         struct md_rdev *rdev;
7855         int spares = 0;
7856         unsigned long flags;
7857
7858         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
7859                 return -EBUSY;
7860
7861         if (!check_stripe_cache(mddev))
7862                 return -ENOSPC;
7863
7864         if (has_failed(conf))
7865                 return -EINVAL;
7866
7867         rdev_for_each(rdev, mddev) {
7868                 if (!test_bit(In_sync, &rdev->flags)
7869                     && !test_bit(Faulty, &rdev->flags))
7870                         spares++;
7871         }
7872
7873         if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
7874                 /* Not enough devices even to make a degraded array
7875                  * of that size
7876                  */
7877                 return -EINVAL;
7878
7879         /* Refuse to reduce size of the array.  Any reductions in
7880          * array size must be through explicit setting of array_size
7881          * attribute.
7882          */
7883         if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
7884             < mddev->array_sectors) {
7885                 pr_warn("md/raid:%s: array size must be reduced before number of disks\n",
7886                         mdname(mddev));
7887                 return -EINVAL;
7888         }
7889
7890         atomic_set(&conf->reshape_stripes, 0);
7891         spin_lock_irq(&conf->device_lock);
7892         write_seqcount_begin(&conf->gen_lock);
7893         conf->previous_raid_disks = conf->raid_disks;
7894         conf->raid_disks += mddev->delta_disks;
7895         conf->prev_chunk_sectors = conf->chunk_sectors;
7896         conf->chunk_sectors = mddev->new_chunk_sectors;
7897         conf->prev_algo = conf->algorithm;
7898         conf->algorithm = mddev->new_layout;
7899         conf->generation++;
7900         /* Code that selects data_offset needs to see the generation update
7901          * if reshape_progress has been set - so a memory barrier needed.
7902          */
7903         smp_mb();
7904         if (mddev->reshape_backwards)
7905                 conf->reshape_progress = raid5_size(mddev, 0, 0);
7906         else
7907                 conf->reshape_progress = 0;
7908         conf->reshape_safe = conf->reshape_progress;
7909         write_seqcount_end(&conf->gen_lock);
7910         spin_unlock_irq(&conf->device_lock);
7911
7912         /* Now make sure any requests that proceeded on the assumption
7913          * the reshape wasn't running - like Discard or Read - have
7914          * completed.
7915          */
7916         mddev_suspend(mddev);
7917         mddev_resume(mddev);
7918
7919         /* Add some new drives, as many as will fit.
7920          * We know there are enough to make the newly sized array work.
7921          * Don't add devices if we are reducing the number of
7922          * devices in the array.  This is because it is not possible
7923          * to correctly record the "partially reconstructed" state of
7924          * such devices during the reshape and confusion could result.
7925          */
7926         if (mddev->delta_disks >= 0) {
7927                 rdev_for_each(rdev, mddev)
7928                         if (rdev->raid_disk < 0 &&
7929                             !test_bit(Faulty, &rdev->flags)) {
7930                                 if (raid5_add_disk(mddev, rdev) == 0) {
7931                                         if (rdev->raid_disk
7932                                             >= conf->previous_raid_disks)
7933                                                 set_bit(In_sync, &rdev->flags);
7934                                         else
7935                                                 rdev->recovery_offset = 0;
7936
7937                                         if (sysfs_link_rdev(mddev, rdev))
7938                                                 /* Failure here is OK */;
7939                                 }
7940                         } else if (rdev->raid_disk >= conf->previous_raid_disks
7941                                    && !test_bit(Faulty, &rdev->flags)) {
7942                                 /* This is a spare that was manually added */
7943                                 set_bit(In_sync, &rdev->flags);
7944                         }
7945
7946                 /* When a reshape changes the number of devices,
7947                  * ->degraded is measured against the larger of the
7948                  * pre and post number of devices.
7949                  */
7950                 spin_lock_irqsave(&conf->device_lock, flags);
7951                 mddev->degraded = raid5_calc_degraded(conf);
7952                 spin_unlock_irqrestore(&conf->device_lock, flags);
7953         }
7954         mddev->raid_disks = conf->raid_disks;
7955         mddev->reshape_position = conf->reshape_progress;
7956         set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
7957
7958         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7959         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7960         clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
7961         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7962         set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7963         mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7964                                                 "reshape");
7965         if (!mddev->sync_thread) {
7966                 mddev->recovery = 0;
7967                 spin_lock_irq(&conf->device_lock);
7968                 write_seqcount_begin(&conf->gen_lock);
7969                 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
7970                 mddev->new_chunk_sectors =
7971                         conf->chunk_sectors = conf->prev_chunk_sectors;
7972                 mddev->new_layout = conf->algorithm = conf->prev_algo;
7973                 rdev_for_each(rdev, mddev)
7974                         rdev->new_data_offset = rdev->data_offset;
7975                 smp_wmb();
7976                 conf->generation --;
7977                 conf->reshape_progress = MaxSector;
7978                 mddev->reshape_position = MaxSector;
7979                 write_seqcount_end(&conf->gen_lock);
7980                 spin_unlock_irq(&conf->device_lock);
7981                 return -EAGAIN;
7982         }
7983         conf->reshape_checkpoint = jiffies;
7984         md_wakeup_thread(mddev->sync_thread);
7985         md_new_event(mddev);
7986         return 0;
7987 }
7988
7989 /* This is called from the reshape thread and should make any
7990  * changes needed in 'conf'
7991  */
7992 static void end_reshape(struct r5conf *conf)
7993 {
7994
7995         if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
7996                 struct md_rdev *rdev;
7997
7998                 spin_lock_irq(&conf->device_lock);
7999                 conf->previous_raid_disks = conf->raid_disks;
8000                 rdev_for_each(rdev, conf->mddev)
8001                         rdev->data_offset = rdev->new_data_offset;
8002                 smp_wmb();
8003                 conf->reshape_progress = MaxSector;
8004                 conf->mddev->reshape_position = MaxSector;
8005                 spin_unlock_irq(&conf->device_lock);
8006                 wake_up(&conf->wait_for_overlap);
8007
8008                 /* read-ahead size must cover two whole stripes, which is
8009                  * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
8010                  */
8011                 if (conf->mddev->queue) {
8012                         int data_disks = conf->raid_disks - conf->max_degraded;
8013                         int stripe = data_disks * ((conf->chunk_sectors << 9)
8014                                                    / PAGE_SIZE);
8015                         if (conf->mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
8016                                 conf->mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
8017                 }
8018         }
8019 }
8020
8021 /* This is called from the raid5d thread with mddev_lock held.
8022  * It makes config changes to the device.
8023  */
8024 static void raid5_finish_reshape(struct mddev *mddev)
8025 {
8026         struct r5conf *conf = mddev->private;
8027
8028         if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
8029
8030                 if (mddev->delta_disks > 0) {
8031                         md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
8032                         if (mddev->queue) {
8033                                 set_capacity(mddev->gendisk, mddev->array_sectors);
8034                                 revalidate_disk(mddev->gendisk);
8035                         }
8036                 } else {
8037                         int d;
8038                         spin_lock_irq(&conf->device_lock);
8039                         mddev->degraded = raid5_calc_degraded(conf);
8040                         spin_unlock_irq(&conf->device_lock);
8041                         for (d = conf->raid_disks ;
8042                              d < conf->raid_disks - mddev->delta_disks;
8043                              d++) {
8044                                 struct md_rdev *rdev = conf->disks[d].rdev;
8045                                 if (rdev)
8046                                         clear_bit(In_sync, &rdev->flags);
8047                                 rdev = conf->disks[d].replacement;
8048                                 if (rdev)
8049                                         clear_bit(In_sync, &rdev->flags);
8050                         }
8051                 }
8052                 mddev->layout = conf->algorithm;
8053                 mddev->chunk_sectors = conf->chunk_sectors;
8054                 mddev->reshape_position = MaxSector;
8055                 mddev->delta_disks = 0;
8056                 mddev->reshape_backwards = 0;
8057         }
8058 }
8059
8060 static void raid5_quiesce(struct mddev *mddev, int state)
8061 {
8062         struct r5conf *conf = mddev->private;
8063
8064         switch(state) {
8065         case 2: /* resume for a suspend */
8066                 wake_up(&conf->wait_for_overlap);
8067                 break;
8068
8069         case 1: /* stop all writes */
8070                 lock_all_device_hash_locks_irq(conf);
8071                 /* '2' tells resync/reshape to pause so that all
8072                  * active stripes can drain
8073                  */
8074                 r5c_flush_cache(conf, INT_MAX);
8075                 conf->quiesce = 2;
8076                 wait_event_cmd(conf->wait_for_quiescent,
8077                                     atomic_read(&conf->active_stripes) == 0 &&
8078                                     atomic_read(&conf->active_aligned_reads) == 0,
8079                                     unlock_all_device_hash_locks_irq(conf),
8080                                     lock_all_device_hash_locks_irq(conf));
8081                 conf->quiesce = 1;
8082                 unlock_all_device_hash_locks_irq(conf);
8083                 /* allow reshape to continue */
8084                 wake_up(&conf->wait_for_overlap);
8085                 break;
8086
8087         case 0: /* re-enable writes */
8088                 lock_all_device_hash_locks_irq(conf);
8089                 conf->quiesce = 0;
8090                 wake_up(&conf->wait_for_quiescent);
8091                 wake_up(&conf->wait_for_overlap);
8092                 unlock_all_device_hash_locks_irq(conf);
8093                 break;
8094         }
8095         r5l_quiesce(conf->log, state);
8096 }
8097
8098 static void *raid45_takeover_raid0(struct mddev *mddev, int level)
8099 {
8100         struct r0conf *raid0_conf = mddev->private;
8101         sector_t sectors;
8102
8103         /* for raid0 takeover only one zone is supported */
8104         if (raid0_conf->nr_strip_zones > 1) {
8105                 pr_warn("md/raid:%s: cannot takeover raid0 with more than one zone.\n",
8106                         mdname(mddev));
8107                 return ERR_PTR(-EINVAL);
8108         }
8109
8110         sectors = raid0_conf->strip_zone[0].zone_end;
8111         sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
8112         mddev->dev_sectors = sectors;
8113         mddev->new_level = level;
8114         mddev->new_layout = ALGORITHM_PARITY_N;
8115         mddev->new_chunk_sectors = mddev->chunk_sectors;
8116         mddev->raid_disks += 1;
8117         mddev->delta_disks = 1;
8118         /* make sure it will be not marked as dirty */
8119         mddev->recovery_cp = MaxSector;
8120
8121         return setup_conf(mddev);
8122 }
8123
8124 static void *raid5_takeover_raid1(struct mddev *mddev)
8125 {
8126         int chunksect;
8127         void *ret;
8128
8129         if (mddev->raid_disks != 2 ||
8130             mddev->degraded > 1)
8131                 return ERR_PTR(-EINVAL);
8132
8133         /* Should check if there are write-behind devices? */
8134
8135         chunksect = 64*2; /* 64K by default */
8136
8137         /* The array must be an exact multiple of chunksize */
8138         while (chunksect && (mddev->array_sectors & (chunksect-1)))
8139                 chunksect >>= 1;
8140
8141         if ((chunksect<<9) < STRIPE_SIZE)
8142                 /* array size does not allow a suitable chunk size */
8143                 return ERR_PTR(-EINVAL);
8144
8145         mddev->new_level = 5;
8146         mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
8147         mddev->new_chunk_sectors = chunksect;
8148
8149         ret = setup_conf(mddev);
8150         if (!IS_ERR(ret))
8151                 mddev_clear_unsupported_flags(mddev,
8152                         UNSUPPORTED_MDDEV_FLAGS);
8153         return ret;
8154 }
8155
8156 static void *raid5_takeover_raid6(struct mddev *mddev)
8157 {
8158         int new_layout;
8159
8160         switch (mddev->layout) {
8161         case ALGORITHM_LEFT_ASYMMETRIC_6:
8162                 new_layout = ALGORITHM_LEFT_ASYMMETRIC;
8163                 break;
8164         case ALGORITHM_RIGHT_ASYMMETRIC_6:
8165                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
8166                 break;
8167         case ALGORITHM_LEFT_SYMMETRIC_6:
8168                 new_layout = ALGORITHM_LEFT_SYMMETRIC;
8169                 break;
8170         case ALGORITHM_RIGHT_SYMMETRIC_6:
8171                 new_layout = ALGORITHM_RIGHT_SYMMETRIC;
8172                 break;
8173         case ALGORITHM_PARITY_0_6:
8174                 new_layout = ALGORITHM_PARITY_0;
8175                 break;
8176         case ALGORITHM_PARITY_N:
8177                 new_layout = ALGORITHM_PARITY_N;
8178                 break;
8179         default:
8180                 return ERR_PTR(-EINVAL);
8181         }
8182         mddev->new_level = 5;
8183         mddev->new_layout = new_layout;
8184         mddev->delta_disks = -1;
8185         mddev->raid_disks -= 1;
8186         return setup_conf(mddev);
8187 }
8188
8189 static int raid5_check_reshape(struct mddev *mddev)
8190 {
8191         /* For a 2-drive array, the layout and chunk size can be changed
8192          * immediately as not restriping is needed.
8193          * For larger arrays we record the new value - after validation
8194          * to be used by a reshape pass.
8195          */
8196         struct r5conf *conf = mddev->private;
8197         int new_chunk = mddev->new_chunk_sectors;
8198
8199         if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
8200                 return -EINVAL;
8201         if (new_chunk > 0) {
8202                 if (!is_power_of_2(new_chunk))
8203                         return -EINVAL;
8204                 if (new_chunk < (PAGE_SIZE>>9))
8205                         return -EINVAL;
8206                 if (mddev->array_sectors & (new_chunk-1))
8207                         /* not factor of array size */
8208                         return -EINVAL;
8209         }
8210
8211         /* They look valid */
8212
8213         if (mddev->raid_disks == 2) {
8214                 /* can make the change immediately */
8215                 if (mddev->new_layout >= 0) {
8216                         conf->algorithm = mddev->new_layout;
8217                         mddev->layout = mddev->new_layout;
8218                 }
8219                 if (new_chunk > 0) {
8220                         conf->chunk_sectors = new_chunk ;
8221                         mddev->chunk_sectors = new_chunk;
8222                 }
8223                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8224                 md_wakeup_thread(mddev->thread);
8225         }
8226         return check_reshape(mddev);
8227 }
8228
8229 static int raid6_check_reshape(struct mddev *mddev)
8230 {
8231         int new_chunk = mddev->new_chunk_sectors;
8232
8233         if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
8234                 return -EINVAL;
8235         if (new_chunk > 0) {
8236                 if (!is_power_of_2(new_chunk))
8237                         return -EINVAL;
8238                 if (new_chunk < (PAGE_SIZE >> 9))
8239                         return -EINVAL;
8240                 if (mddev->array_sectors & (new_chunk-1))
8241                         /* not factor of array size */
8242                         return -EINVAL;
8243         }
8244
8245         /* They look valid */
8246         return check_reshape(mddev);
8247 }
8248
8249 static void *raid5_takeover(struct mddev *mddev)
8250 {
8251         /* raid5 can take over:
8252          *  raid0 - if there is only one strip zone - make it a raid4 layout
8253          *  raid1 - if there are two drives.  We need to know the chunk size
8254          *  raid4 - trivial - just use a raid4 layout.
8255          *  raid6 - Providing it is a *_6 layout
8256          */
8257         if (mddev->level == 0)
8258                 return raid45_takeover_raid0(mddev, 5);
8259         if (mddev->level == 1)
8260                 return raid5_takeover_raid1(mddev);
8261         if (mddev->level == 4) {
8262                 mddev->new_layout = ALGORITHM_PARITY_N;
8263                 mddev->new_level = 5;
8264                 return setup_conf(mddev);
8265         }
8266         if (mddev->level == 6)
8267                 return raid5_takeover_raid6(mddev);
8268
8269         return ERR_PTR(-EINVAL);
8270 }
8271
8272 static void *raid4_takeover(struct mddev *mddev)
8273 {
8274         /* raid4 can take over:
8275          *  raid0 - if there is only one strip zone
8276          *  raid5 - if layout is right
8277          */
8278         if (mddev->level == 0)
8279                 return raid45_takeover_raid0(mddev, 4);
8280         if (mddev->level == 5 &&
8281             mddev->layout == ALGORITHM_PARITY_N) {
8282                 mddev->new_layout = 0;
8283                 mddev->new_level = 4;
8284                 return setup_conf(mddev);
8285         }
8286         return ERR_PTR(-EINVAL);
8287 }
8288
8289 static struct md_personality raid5_personality;
8290
8291 static void *raid6_takeover(struct mddev *mddev)
8292 {
8293         /* Currently can only take over a raid5.  We map the
8294          * personality to an equivalent raid6 personality
8295          * with the Q block at the end.
8296          */
8297         int new_layout;
8298
8299         if (mddev->pers != &raid5_personality)
8300                 return ERR_PTR(-EINVAL);
8301         if (mddev->degraded > 1)
8302                 return ERR_PTR(-EINVAL);
8303         if (mddev->raid_disks > 253)
8304                 return ERR_PTR(-EINVAL);
8305         if (mddev->raid_disks < 3)
8306                 return ERR_PTR(-EINVAL);
8307
8308         switch (mddev->layout) {
8309         case ALGORITHM_LEFT_ASYMMETRIC:
8310                 new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
8311                 break;
8312         case ALGORITHM_RIGHT_ASYMMETRIC:
8313                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
8314                 break;
8315         case ALGORITHM_LEFT_SYMMETRIC:
8316                 new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
8317                 break;
8318         case ALGORITHM_RIGHT_SYMMETRIC:
8319                 new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
8320                 break;
8321         case ALGORITHM_PARITY_0:
8322                 new_layout = ALGORITHM_PARITY_0_6;
8323                 break;
8324         case ALGORITHM_PARITY_N:
8325                 new_layout = ALGORITHM_PARITY_N;
8326                 break;
8327         default:
8328                 return ERR_PTR(-EINVAL);
8329         }
8330         mddev->new_level = 6;
8331         mddev->new_layout = new_layout;
8332         mddev->delta_disks = 1;
8333         mddev->raid_disks += 1;
8334         return setup_conf(mddev);
8335 }
8336
8337 static void raid5_reset_stripe_cache(struct mddev *mddev)
8338 {
8339         struct r5conf *conf = mddev->private;
8340
8341         mutex_lock(&conf->cache_size_mutex);
8342         while (conf->max_nr_stripes &&
8343                drop_one_stripe(conf))
8344                 ;
8345         while (conf->min_nr_stripes > conf->max_nr_stripes &&
8346                grow_one_stripe(conf, GFP_KERNEL))
8347                 ;
8348         mutex_unlock(&conf->cache_size_mutex);
8349 }
8350
8351 static int raid5_change_consistency_policy(struct mddev *mddev, const char *buf)
8352 {
8353         struct r5conf *conf;
8354         int err;
8355
8356         err = mddev_lock(mddev);
8357         if (err)
8358                 return err;
8359         conf = mddev->private;
8360         if (!conf) {
8361                 mddev_unlock(mddev);
8362                 return -ENODEV;
8363         }
8364
8365         if (strncmp(buf, "ppl", 3) == 0 && !raid5_has_ppl(conf)) {
8366                 mddev_suspend(mddev);
8367                 set_bit(MD_HAS_PPL, &mddev->flags);
8368                 err = log_init(conf, NULL);
8369                 if (!err)
8370                         raid5_reset_stripe_cache(mddev);
8371                 mddev_resume(mddev);
8372         } else if (strncmp(buf, "resync", 6) == 0 && raid5_has_ppl(conf)) {
8373                 mddev_suspend(mddev);
8374                 log_exit(conf);
8375                 raid5_reset_stripe_cache(mddev);
8376                 mddev_resume(mddev);
8377         } else {
8378                 err = -EINVAL;
8379         }
8380
8381         if (!err)
8382                 md_update_sb(mddev, 1);
8383
8384         mddev_unlock(mddev);
8385
8386         return err;
8387 }
8388
8389 static struct md_personality raid6_personality =
8390 {
8391         .name           = "raid6",
8392         .level          = 6,
8393         .owner          = THIS_MODULE,
8394         .make_request   = raid5_make_request,
8395         .run            = raid5_run,
8396         .free           = raid5_free,
8397         .status         = raid5_status,
8398         .error_handler  = raid5_error,
8399         .hot_add_disk   = raid5_add_disk,
8400         .hot_remove_disk= raid5_remove_disk,
8401         .spare_active   = raid5_spare_active,
8402         .sync_request   = raid5_sync_request,
8403         .resize         = raid5_resize,
8404         .size           = raid5_size,
8405         .check_reshape  = raid6_check_reshape,
8406         .start_reshape  = raid5_start_reshape,
8407         .finish_reshape = raid5_finish_reshape,
8408         .quiesce        = raid5_quiesce,
8409         .takeover       = raid6_takeover,
8410         .congested      = raid5_congested,
8411 };
8412 static struct md_personality raid5_personality =
8413 {
8414         .name           = "raid5",
8415         .level          = 5,
8416         .owner          = THIS_MODULE,
8417         .make_request   = raid5_make_request,
8418         .run            = raid5_run,
8419         .free           = raid5_free,
8420         .status         = raid5_status,
8421         .error_handler  = raid5_error,
8422         .hot_add_disk   = raid5_add_disk,
8423         .hot_remove_disk= raid5_remove_disk,
8424         .spare_active   = raid5_spare_active,
8425         .sync_request   = raid5_sync_request,
8426         .resize         = raid5_resize,
8427         .size           = raid5_size,
8428         .check_reshape  = raid5_check_reshape,
8429         .start_reshape  = raid5_start_reshape,
8430         .finish_reshape = raid5_finish_reshape,
8431         .quiesce        = raid5_quiesce,
8432         .takeover       = raid5_takeover,
8433         .congested      = raid5_congested,
8434         .change_consistency_policy = raid5_change_consistency_policy,
8435 };
8436
8437 static struct md_personality raid4_personality =
8438 {
8439         .name           = "raid4",
8440         .level          = 4,
8441         .owner          = THIS_MODULE,
8442         .make_request   = raid5_make_request,
8443         .run            = raid5_run,
8444         .free           = raid5_free,
8445         .status         = raid5_status,
8446         .error_handler  = raid5_error,
8447         .hot_add_disk   = raid5_add_disk,
8448         .hot_remove_disk= raid5_remove_disk,
8449         .spare_active   = raid5_spare_active,
8450         .sync_request   = raid5_sync_request,
8451         .resize         = raid5_resize,
8452         .size           = raid5_size,
8453         .check_reshape  = raid5_check_reshape,
8454         .start_reshape  = raid5_start_reshape,
8455         .finish_reshape = raid5_finish_reshape,
8456         .quiesce        = raid5_quiesce,
8457         .takeover       = raid4_takeover,
8458         .congested      = raid5_congested,
8459 };
8460
8461 static int __init raid5_init(void)
8462 {
8463         int ret;
8464
8465         raid5_wq = alloc_workqueue("raid5wq",
8466                 WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE|WQ_SYSFS, 0);
8467         if (!raid5_wq)
8468                 return -ENOMEM;
8469
8470         ret = cpuhp_setup_state_multi(CPUHP_MD_RAID5_PREPARE,
8471                                       "md/raid5:prepare",
8472                                       raid456_cpu_up_prepare,
8473                                       raid456_cpu_dead);
8474         if (ret) {
8475                 destroy_workqueue(raid5_wq);
8476                 return ret;
8477         }
8478         register_md_personality(&raid6_personality);
8479         register_md_personality(&raid5_personality);
8480         register_md_personality(&raid4_personality);
8481         return 0;
8482 }
8483
8484 static void raid5_exit(void)
8485 {
8486         unregister_md_personality(&raid6_personality);
8487         unregister_md_personality(&raid5_personality);
8488         unregister_md_personality(&raid4_personality);
8489         cpuhp_remove_multi_state(CPUHP_MD_RAID5_PREPARE);
8490         destroy_workqueue(raid5_wq);
8491 }
8492
8493 module_init(raid5_init);
8494 module_exit(raid5_exit);
8495 MODULE_LICENSE("GPL");
8496 MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
8497 MODULE_ALIAS("md-personality-4"); /* RAID5 */
8498 MODULE_ALIAS("md-raid5");
8499 MODULE_ALIAS("md-raid4");
8500 MODULE_ALIAS("md-level-5");
8501 MODULE_ALIAS("md-level-4");
8502 MODULE_ALIAS("md-personality-8"); /* RAID6 */
8503 MODULE_ALIAS("md-raid6");
8504 MODULE_ALIAS("md-level-6");
8505
8506 /* This used to be two separate modules, they were: */
8507 MODULE_ALIAS("raid5");
8508 MODULE_ALIAS("raid6");