drivers/md/raid5.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * raid5.c : Multiple Devices driver for Linux
   4  *         Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
   5  *         Copyright (C) 1999, 2000 Ingo Molnar
   6  *         Copyright (C) 2002, 2003 H. Peter Anvin
   7  *
   8  * RAID-4/5/6 management functions.
   9  * Thanks to Penguin Computing for making the RAID-6 development possible
  10  * by donating a test server!
  11  */
  12
  13 /*
  14  * BITMAP UNPLUGGING:
  15  *
  16  * The sequencing for updating the bitmap reliably is a little
  17  * subtle (and I got it wrong the first time) so it deserves some
  18  * explanation.
  19  *
  20  * We group bitmap updates into batches.  Each batch has a number.
  21  * We may write out several batches at once, but that isn't very important.
  22  * conf->seq_write is the number of the last batch successfully written.
  23  * conf->seq_flush is the number of the last batch that was closed to
  24  *    new additions.
  25  * When we discover that we will need to write to any block in a stripe
  26  * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
  27  * the number of the batch it will be in. This is seq_flush+1.
  28  * When we are ready to do a write, if that batch hasn't been written yet,
  29  *   we plug the array and queue the stripe for later.
  30  * When an unplug happens, we increment bm_flush, thus closing the current
  31  *   batch.
  32  * When we notice that bm_flush > bm_write, we write out all pending updates
  33  * to the bitmap, and advance bm_write to where bm_flush was.
  34  * This may occasionally write a bit out twice, but is sure never to
  35  * miss any bits.
  36  */
  37
  38 #include <linux/blkdev.h>
  39 #include <linux/kthread.h>
  40 #include <linux/raid/pq.h>
  41 #include <linux/async_tx.h>
  42 #include <linux/module.h>
  43 #include <linux/async.h>
  44 #include <linux/seq_file.h>
  45 #include <linux/cpu.h>
  46 #include <linux/slab.h>
  47 #include <linux/ratelimit.h>
  48 #include <linux/nodemask.h>
  49
  50 #include <trace/events/block.h>
  51 #include <linux/list_sort.h>
  52
  53 #include "md.h"
  54 #include "raid5.h"
  55 #include "raid0.h"
  56 #include "md-bitmap.h"
  57 #include "raid5-log.h"
  58
  59 #define UNSUPPORTED_MDDEV_FLAGS (1L << MD_FAILFAST_SUPPORTED)
  60
  61 #define cpu_to_group(cpu) cpu_to_node(cpu)
  62 #define ANY_GROUP NUMA_NO_NODE
  63
  64 #define RAID5_MAX_REQ_STRIPES 256
  65
  66 static bool devices_handle_discard_safely = false;
  67 module_param(devices_handle_discard_safely, bool, 0644);
  68 MODULE_PARM_DESC(devices_handle_discard_safely,
  69                  "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
  70 static struct workqueue_struct *raid5_wq;
  71
  72 static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
  73 {
  74         int hash = (sect >> RAID5_STRIPE_SHIFT(conf)) & HASH_MASK;
  75         return &conf->stripe_hashtbl[hash];
  76 }
  77
  78 static inline int stripe_hash_locks_hash(struct r5conf *conf, sector_t sect)
  79 {
  80         return (sect >> RAID5_STRIPE_SHIFT(conf)) & STRIPE_HASH_LOCKS_MASK;
  81 }
  82
  83 static inline void lock_device_hash_lock(struct r5conf *conf, int hash)
  84         __acquires(&conf->device_lock)
  85 {
  86         spin_lock_irq(conf->hash_locks + hash);
  87         spin_lock(&conf->device_lock);
  88 }
  89
  90 static inline void unlock_device_hash_lock(struct r5conf *conf, int hash)
  91         __releases(&conf->device_lock)
  92 {
  93         spin_unlock(&conf->device_lock);
  94         spin_unlock_irq(conf->hash_locks + hash);
  95 }
  96
  97 static inline void lock_all_device_hash_locks_irq(struct r5conf *conf)
  98         __acquires(&conf->device_lock)
  99 {
 100         int i;
 101         spin_lock_irq(conf->hash_locks);
 102         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
 103                 spin_lock_nest_lock(conf->hash_locks + i, conf->hash_locks);
 104         spin_lock(&conf->device_lock);
 105 }
 106
 107 static inline void unlock_all_device_hash_locks_irq(struct r5conf *conf)
 108         __releases(&conf->device_lock)
 109 {
 110         int i;
 111         spin_unlock(&conf->device_lock);
 112         for (i = NR_STRIPE_HASH_LOCKS - 1; i; i--)
 113                 spin_unlock(conf->hash_locks + i);
 114         spin_unlock_irq(conf->hash_locks);
 115 }
 116
 117 /* Find first data disk in a raid6 stripe */
 118 static inline int raid6_d0(struct stripe_head *sh)
 119 {
 120         if (sh->ddf_layout)
 121                 /* ddf always start from first device */
 122                 return 0;
 123         /* md starts just after Q block */
 124         if (sh->qd_idx == sh->disks - 1)
 125                 return 0;
 126         else
 127                 return sh->qd_idx + 1;
 128 }
 129 static inline int raid6_next_disk(int disk, int raid_disks)
 130 {
 131         disk++;
 132         return (disk < raid_disks) ? disk : 0;
 133 }
 134
 135 /* When walking through the disks in a raid5, starting at raid6_d0,
 136  * We need to map each disk to a 'slot', where the data disks are slot
 137  * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
 138  * is raid_disks-1.  This help does that mapping.
 139  */
 140 static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
 141                              int *count, int syndrome_disks)
 142 {
 143         int slot = *count;
 144
 145         if (sh->ddf_layout)
 146                 (*count)++;
 147         if (idx == sh->pd_idx)
 148                 return syndrome_disks;
 149         if (idx == sh->qd_idx)
 150                 return syndrome_disks + 1;
 151         if (!sh->ddf_layout)
 152                 (*count)++;
 153         return slot;
 154 }
 155
 156 static void print_raid5_conf (struct r5conf *conf);
 157
 158 static int stripe_operations_active(struct stripe_head *sh)
 159 {
 160         return sh->check_state || sh->reconstruct_state ||
 161                test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
 162                test_bit(STRIPE_COMPUTE_RUN, &sh->state);
 163 }
 164
 165 static bool stripe_is_lowprio(struct stripe_head *sh)
 166 {
 167         return (test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) ||
 168                 test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) &&
 169                !test_bit(STRIPE_R5C_CACHING, &sh->state);
 170 }
 171
 172 static void raid5_wakeup_stripe_thread(struct stripe_head *sh)
 173         __must_hold(&sh->raid_conf->device_lock)
 174 {
 175         struct r5conf *conf = sh->raid_conf;
 176         struct r5worker_group *group;
 177         int thread_cnt;
 178         int i, cpu = sh->cpu;
 179
 180         if (!cpu_online(cpu)) {
 181                 cpu = cpumask_any(cpu_online_mask);
 182                 sh->cpu = cpu;
 183         }
 184
 185         if (list_empty(&sh->lru)) {
 186                 struct r5worker_group *group;
 187                 group = conf->worker_groups + cpu_to_group(cpu);
 188                 if (stripe_is_lowprio(sh))
 189                         list_add_tail(&sh->lru, &group->loprio_list);
 190                 else
 191                         list_add_tail(&sh->lru, &group->handle_list);
 192                 group->stripes_cnt++;
 193                 sh->group = group;
 194         }
 195
 196         if (conf->worker_cnt_per_group == 0) {
 197                 md_wakeup_thread(conf->mddev->thread);
 198                 return;
 199         }
 200
 201         group = conf->worker_groups + cpu_to_group(sh->cpu);
 202
 203         group->workers[0].working = true;
 204         /* at least one worker should run to avoid race */
 205         queue_work_on(sh->cpu, raid5_wq, &group->workers[0].work);
 206
 207         thread_cnt = group->stripes_cnt / MAX_STRIPE_BATCH - 1;
 208         /* wakeup more workers */
 209         for (i = 1; i < conf->worker_cnt_per_group && thread_cnt > 0; i++) {
 210                 if (group->workers[i].working == false) {
 211                         group->workers[i].working = true;
 212                         queue_work_on(sh->cpu, raid5_wq,
 213                                       &group->workers[i].work);
 214                         thread_cnt--;
 215                 }
 216         }
 217 }
 218
 219 static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh,
 220                               struct list_head *temp_inactive_list)
 221         __must_hold(&conf->device_lock)
 222 {
 223         int i;
 224         int injournal = 0;      /* number of date pages with R5_InJournal */
 225
 226         BUG_ON(!list_empty(&sh->lru));
 227         BUG_ON(atomic_read(&conf->active_stripes)==0);
 228
 229         if (r5c_is_writeback(conf->log))
 230                 for (i = sh->disks; i--; )
 231                         if (test_bit(R5_InJournal, &sh->dev[i].flags))
 232                                 injournal++;
 233         /*
 234          * In the following cases, the stripe cannot be released to cached
 235          * lists. Therefore, we make the stripe write out and set
 236          * STRIPE_HANDLE:
 237          *   1. when quiesce in r5c write back;
 238          *   2. when resync is requested fot the stripe.
 239          */
 240         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) ||
 241             (conf->quiesce && r5c_is_writeback(conf->log) &&
 242              !test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0)) {
 243                 if (test_bit(STRIPE_R5C_CACHING, &sh->state))
 244                         r5c_make_stripe_write_out(sh);
 245                 set_bit(STRIPE_HANDLE, &sh->state);
 246         }
 247
 248         if (test_bit(STRIPE_HANDLE, &sh->state)) {
 249                 if (test_bit(STRIPE_DELAYED, &sh->state) &&
 250                     !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 251                         list_add_tail(&sh->lru, &conf->delayed_list);
 252                 else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
 253                            sh->bm_seq - conf->seq_write > 0)
 254                         list_add_tail(&sh->lru, &conf->bitmap_list);
 255                 else {
 256                         clear_bit(STRIPE_DELAYED, &sh->state);
 257                         clear_bit(STRIPE_BIT_DELAY, &sh->state);
 258                         if (conf->worker_cnt_per_group == 0) {
 259                                 if (stripe_is_lowprio(sh))
 260                                         list_add_tail(&sh->lru,
 261                                                         &conf->loprio_list);
 262                                 else
 263                                         list_add_tail(&sh->lru,
 264                                                         &conf->handle_list);
 265                         } else {
 266                                 raid5_wakeup_stripe_thread(sh);
 267                                 return;
 268                         }
 269                 }
 270                 md_wakeup_thread(conf->mddev->thread);
 271         } else {
 272                 BUG_ON(stripe_operations_active(sh));
 273                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 274                         if (atomic_dec_return(&conf->preread_active_stripes)
 275                             < IO_THRESHOLD)
 276                                 md_wakeup_thread(conf->mddev->thread);
 277                 atomic_dec(&conf->active_stripes);
 278                 if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
 279                         if (!r5c_is_writeback(conf->log))
 280                                 list_add_tail(&sh->lru, temp_inactive_list);
 281                         else {
 282                                 WARN_ON(test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags));
 283                                 if (injournal == 0)
 284                                         list_add_tail(&sh->lru, temp_inactive_list);
 285                                 else if (injournal == conf->raid_disks - conf->max_degraded) {
 286                                         /* full stripe */
 287                                         if (!test_and_set_bit(STRIPE_R5C_FULL_STRIPE, &sh->state))
 288                                                 atomic_inc(&conf->r5c_cached_full_stripes);
 289                                         if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
 290                                                 atomic_dec(&conf->r5c_cached_partial_stripes);
 291                                         list_add_tail(&sh->lru, &conf->r5c_full_stripe_list);
 292                                         r5c_check_cached_full_stripe(conf);
 293                                 } else
 294                                         /*
 295                                          * STRIPE_R5C_PARTIAL_STRIPE is set in
 296                                          * r5c_try_caching_write(). No need to
 297                                          * set it again.
 298                                          */
 299                                         list_add_tail(&sh->lru, &conf->r5c_partial_stripe_list);
 300                         }
 301                 }
 302         }
 303 }
 304
 305 static void __release_stripe(struct r5conf *conf, struct stripe_head *sh,
 306                              struct list_head *temp_inactive_list)
 307         __must_hold(&conf->device_lock)
 308 {
 309         if (atomic_dec_and_test(&sh->count))
 310                 do_release_stripe(conf, sh, temp_inactive_list);
 311 }
 312
 313 /*
 314  * @hash could be NR_STRIPE_HASH_LOCKS, then we have a list of inactive_list
 315  *
 316  * Be careful: Only one task can add/delete stripes from temp_inactive_list at
 317  * given time. Adding stripes only takes device lock, while deleting stripes
 318  * only takes hash lock.
 319  */
 320 static void release_inactive_stripe_list(struct r5conf *conf,
 321                                          struct list_head *temp_inactive_list,
 322                                          int hash)
 323 {
 324         int size;
 325         bool do_wakeup = false;
 326         unsigned long flags;
 327
 328         if (hash == NR_STRIPE_HASH_LOCKS) {
 329                 size = NR_STRIPE_HASH_LOCKS;
 330                 hash = NR_STRIPE_HASH_LOCKS - 1;
 331         } else
 332                 size = 1;
 333         while (size) {
 334                 struct list_head *list = &temp_inactive_list[size - 1];
 335
 336                 /*
 337                  * We don't hold any lock here yet, raid5_get_active_stripe() might
 338                  * remove stripes from the list
 339                  */
 340                 if (!list_empty_careful(list)) {
 341                         spin_lock_irqsave(conf->hash_locks + hash, flags);
 342                         if (list_empty(conf->inactive_list + hash) &&
 343                             !list_empty(list))
 344                                 atomic_dec(&conf->empty_inactive_list_nr);
 345                         list_splice_tail_init(list, conf->inactive_list + hash);
 346                         do_wakeup = true;
 347                         spin_unlock_irqrestore(conf->hash_locks + hash, flags);
 348                 }
 349                 size--;
 350                 hash--;
 351         }
 352
 353         if (do_wakeup) {
 354                 wake_up(&conf->wait_for_stripe);
 355                 if (atomic_read(&conf->active_stripes) == 0)
 356                         wake_up(&conf->wait_for_quiescent);
 357                 if (conf->retry_read_aligned)
 358                         md_wakeup_thread(conf->mddev->thread);
 359         }
 360 }
 361
 362 static int release_stripe_list(struct r5conf *conf,
 363                                struct list_head *temp_inactive_list)
 364         __must_hold(&conf->device_lock)
 365 {
 366         struct stripe_head *sh, *t;
 367         int count = 0;
 368         struct llist_node *head;
 369
 370         head = llist_del_all(&conf->released_stripes);
 371         head = llist_reverse_order(head);
 372         llist_for_each_entry_safe(sh, t, head, release_list) {
 373                 int hash;
 374
 375                 /* sh could be readded after STRIPE_ON_RELEASE_LIST is cleard */
 376                 smp_mb();
 377                 clear_bit(STRIPE_ON_RELEASE_LIST, &sh->state);
 378                 /*
 379                  * Don't worry the bit is set here, because if the bit is set
 380                  * again, the count is always > 1. This is true for
 381                  * STRIPE_ON_UNPLUG_LIST bit too.
 382                  */
 383                 hash = sh->hash_lock_index;
 384                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
 385                 count++;
 386         }
 387
 388         return count;
 389 }
 390
 391 void raid5_release_stripe(struct stripe_head *sh)
 392 {
 393         struct r5conf *conf = sh->raid_conf;
 394         unsigned long flags;
 395         struct list_head list;
 396         int hash;
 397         bool wakeup;
 398
 399         /* Avoid release_list until the last reference.
 400          */
 401         if (atomic_add_unless(&sh->count, -1, 1))
 402                 return;
 403
 404         if (unlikely(!conf->mddev->thread) ||
 405                 test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state))
 406                 goto slow_path;
 407         wakeup = llist_add(&sh->release_list, &conf->released_stripes);
 408         if (wakeup)
 409                 md_wakeup_thread(conf->mddev->thread);
 410         return;
 411 slow_path:
 412         /* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */
 413         if (atomic_dec_and_lock_irqsave(&sh->count, &conf->device_lock, flags)) {
 414                 INIT_LIST_HEAD(&list);
 415                 hash = sh->hash_lock_index;
 416                 do_release_stripe(conf, sh, &list);
 417                 spin_unlock_irqrestore(&conf->device_lock, flags);
 418                 release_inactive_stripe_list(conf, &list, hash);
 419         }
 420 }
 421
 422 static inline void remove_hash(struct stripe_head *sh)
 423 {
 424         pr_debug("remove_hash(), stripe %llu\n",
 425                 (unsigned long long)sh->sector);
 426
 427         hlist_del_init(&sh->hash);
 428 }
 429
 430 static inline void insert_hash(struct r5conf *conf, struct stripe_head *sh)
 431 {
 432         struct hlist_head *hp = stripe_hash(conf, sh->sector);
 433
 434         pr_debug("insert_hash(), stripe %llu\n",
 435                 (unsigned long long)sh->sector);
 436
 437         hlist_add_head(&sh->hash, hp);
 438 }
 439
 440 /* find an idle stripe, make sure it is unhashed, and return it. */
 441 static struct stripe_head *get_free_stripe(struct r5conf *conf, int hash)
 442 {
 443         struct stripe_head *sh = NULL;
 444         struct list_head *first;
 445
 446         if (list_empty(conf->inactive_list + hash))
 447                 goto out;
 448         first = (conf->inactive_list + hash)->next;
 449         sh = list_entry(first, struct stripe_head, lru);
 450         list_del_init(first);
 451         remove_hash(sh);
 452         atomic_inc(&conf->active_stripes);
 453         BUG_ON(hash != sh->hash_lock_index);
 454         if (list_empty(conf->inactive_list + hash))
 455                 atomic_inc(&conf->empty_inactive_list_nr);
 456 out:
 457         return sh;
 458 }
 459
 460 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
 461 static void free_stripe_pages(struct stripe_head *sh)
 462 {
 463         int i;
 464         struct page *p;
 465
 466         /* Have not allocate page pool */
 467         if (!sh->pages)
 468                 return;
 469
 470         for (i = 0; i < sh->nr_pages; i++) {
 471                 p = sh->pages[i];
 472                 if (p)
 473                         put_page(p);
 474                 sh->pages[i] = NULL;
 475         }
 476 }
 477
 478 static int alloc_stripe_pages(struct stripe_head *sh, gfp_t gfp)
 479 {
 480         int i;
 481         struct page *p;
 482
 483         for (i = 0; i < sh->nr_pages; i++) {
 484                 /* The page have allocated. */
 485                 if (sh->pages[i])
 486                         continue;
 487
 488                 p = alloc_page(gfp);
 489                 if (!p) {
 490                         free_stripe_pages(sh);
 491                         return -ENOMEM;
 492                 }
 493                 sh->pages[i] = p;
 494         }
 495         return 0;
 496 }
 497
 498 static int
 499 init_stripe_shared_pages(struct stripe_head *sh, struct r5conf *conf, int disks)
 500 {
 501         int nr_pages, cnt;
 502
 503         if (sh->pages)
 504                 return 0;
 505
 506         /* Each of the sh->dev[i] need one conf->stripe_size */
 507         cnt = PAGE_SIZE / conf->stripe_size;
 508         nr_pages = (disks + cnt - 1) / cnt;
 509
 510         sh->pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
 511         if (!sh->pages)
 512                 return -ENOMEM;
 513         sh->nr_pages = nr_pages;
 514         sh->stripes_per_page = cnt;
 515         return 0;
 516 }
 517 #endif
 518
 519 static void shrink_buffers(struct stripe_head *sh)
 520 {
 521         int i;
 522         int num = sh->raid_conf->pool_size;
 523
 524 #if PAGE_SIZE == DEFAULT_STRIPE_SIZE
 525         for (i = 0; i < num ; i++) {
 526                 struct page *p;
 527
 528                 WARN_ON(sh->dev[i].page != sh->dev[i].orig_page);
 529                 p = sh->dev[i].page;
 530                 if (!p)
 531                         continue;
 532                 sh->dev[i].page = NULL;
 533                 put_page(p);
 534         }
 535 #else
 536         for (i = 0; i < num; i++)
 537                 sh->dev[i].page = NULL;
 538         free_stripe_pages(sh); /* Free pages */
 539 #endif
 540 }
 541
 542 static int grow_buffers(struct stripe_head *sh, gfp_t gfp)
 543 {
 544         int i;
 545         int num = sh->raid_conf->pool_size;
 546
 547 #if PAGE_SIZE == DEFAULT_STRIPE_SIZE
 548         for (i = 0; i < num; i++) {
 549                 struct page *page;
 550
 551                 if (!(page = alloc_page(gfp))) {
 552                         return 1;
 553                 }
 554                 sh->dev[i].page = page;
 555                 sh->dev[i].orig_page = page;
 556                 sh->dev[i].offset = 0;
 557         }
 558 #else
 559         if (alloc_stripe_pages(sh, gfp))
 560                 return -ENOMEM;
 561
 562         for (i = 0; i < num; i++) {
 563                 sh->dev[i].page = raid5_get_dev_page(sh, i);
 564                 sh->dev[i].orig_page = sh->dev[i].page;
 565                 sh->dev[i].offset = raid5_get_page_offset(sh, i);
 566         }
 567 #endif
 568         return 0;
 569 }
 570
 571 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
 572                             struct stripe_head *sh);
 573
 574 static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
 575 {
 576         struct r5conf *conf = sh->raid_conf;
 577         int i, seq;
 578
 579         BUG_ON(atomic_read(&sh->count) != 0);
 580         BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
 581         BUG_ON(stripe_operations_active(sh));
 582         BUG_ON(sh->batch_head);
 583
 584         pr_debug("init_stripe called, stripe %llu\n",
 585                 (unsigned long long)sector);
 586 retry:
 587         seq = read_seqcount_begin(&conf->gen_lock);
 588         sh->generation = conf->generation - previous;
 589         sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
 590         sh->sector = sector;
 591         stripe_set_idx(sector, conf, previous, sh);
 592         sh->state = 0;
 593
 594         for (i = sh->disks; i--; ) {
 595                 struct r5dev *dev = &sh->dev[i];
 596
 597                 if (dev->toread || dev->read || dev->towrite || dev->written ||
 598                     test_bit(R5_LOCKED, &dev->flags)) {
 599                         pr_err("sector=%llx i=%d %p %p %p %p %d\n",
 600                                (unsigned long long)sh->sector, i, dev->toread,
 601                                dev->read, dev->towrite, dev->written,
 602                                test_bit(R5_LOCKED, &dev->flags));
 603                         WARN_ON(1);
 604                 }
 605                 dev->flags = 0;
 606                 dev->sector = raid5_compute_blocknr(sh, i, previous);
 607         }
 608         if (read_seqcount_retry(&conf->gen_lock, seq))
 609                 goto retry;
 610         sh->overwrite_disks = 0;
 611         insert_hash(conf, sh);
 612         sh->cpu = smp_processor_id();
 613         set_bit(STRIPE_BATCH_READY, &sh->state);
 614 }
 615
 616 static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
 617                                          short generation)
 618 {
 619         struct stripe_head *sh;
 620
 621         pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
 622         hlist_for_each_entry(sh, stripe_hash(conf, sector), hash)
 623                 if (sh->sector == sector && sh->generation == generation)
 624                         return sh;
 625         pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
 626         return NULL;
 627 }
 628
 629 static struct stripe_head *find_get_stripe(struct r5conf *conf,
 630                 sector_t sector, short generation, int hash)
 631 {
 632         int inc_empty_inactive_list_flag;
 633         struct stripe_head *sh;
 634
 635         sh = __find_stripe(conf, sector, generation);
 636         if (!sh)
 637                 return NULL;
 638
 639         if (atomic_inc_not_zero(&sh->count))
 640                 return sh;
 641
 642         /*
 643          * Slow path. The reference count is zero which means the stripe must
 644          * be on a list (sh->lru). Must remove the stripe from the list that
 645          * references it with the device_lock held.
 646          */
 647
 648         spin_lock(&conf->device_lock);
 649         if (!atomic_read(&sh->count)) {
 650                 if (!test_bit(STRIPE_HANDLE, &sh->state))
 651                         atomic_inc(&conf->active_stripes);
 652                 BUG_ON(list_empty(&sh->lru) &&
 653                        !test_bit(STRIPE_EXPANDING, &sh->state));
 654                 inc_empty_inactive_list_flag = 0;
 655                 if (!list_empty(conf->inactive_list + hash))
 656                         inc_empty_inactive_list_flag = 1;
 657                 list_del_init(&sh->lru);
 658                 if (list_empty(conf->inactive_list + hash) &&
 659                     inc_empty_inactive_list_flag)
 660                         atomic_inc(&conf->empty_inactive_list_nr);
 661                 if (sh->group) {
 662                         sh->group->stripes_cnt--;
 663                         sh->group = NULL;
 664                 }
 665         }
 666         atomic_inc(&sh->count);
 667         spin_unlock(&conf->device_lock);
 668
 669         return sh;
 670 }
 671
 672 /*
 673  * Need to check if array has failed when deciding whether to:
 674  *  - start an array
 675  *  - remove non-faulty devices
 676  *  - add a spare
 677  *  - allow a reshape
 678  * This determination is simple when no reshape is happening.
 679  * However if there is a reshape, we need to carefully check
 680  * both the before and after sections.
 681  * This is because some failed devices may only affect one
 682  * of the two sections, and some non-in_sync devices may
 683  * be insync in the section most affected by failed devices.
 684  *
 685  * Most calls to this function hold &conf->device_lock. Calls
 686  * in raid5_run() do not require the lock as no other threads
 687  * have been started yet.
 688  */
 689 int raid5_calc_degraded(struct r5conf *conf)
 690 {
 691         int degraded, degraded2;
 692         int i;
 693
 694         rcu_read_lock();
 695         degraded = 0;
 696         for (i = 0; i < conf->previous_raid_disks; i++) {
 697                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 698                 if (rdev && test_bit(Faulty, &rdev->flags))
 699                         rdev = rcu_dereference(conf->disks[i].replacement);
 700                 if (!rdev || test_bit(Faulty, &rdev->flags))
 701                         degraded++;
 702                 else if (test_bit(In_sync, &rdev->flags))
 703                         ;
 704                 else
 705                         /* not in-sync or faulty.
 706                          * If the reshape increases the number of devices,
 707                          * this is being recovered by the reshape, so
 708                          * this 'previous' section is not in_sync.
 709                          * If the number of devices is being reduced however,
 710                          * the device can only be part of the array if
 711                          * we are reverting a reshape, so this section will
 712                          * be in-sync.
 713                          */
 714                         if (conf->raid_disks >= conf->previous_raid_disks)
 715                                 degraded++;
 716         }
 717         rcu_read_unlock();
 718         if (conf->raid_disks == conf->previous_raid_disks)
 719                 return degraded;
 720         rcu_read_lock();
 721         degraded2 = 0;
 722         for (i = 0; i < conf->raid_disks; i++) {
 723                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 724                 if (rdev && test_bit(Faulty, &rdev->flags))
 725                         rdev = rcu_dereference(conf->disks[i].replacement);
 726                 if (!rdev || test_bit(Faulty, &rdev->flags))
 727                         degraded2++;
 728                 else if (test_bit(In_sync, &rdev->flags))
 729                         ;
 730                 else
 731                         /* not in-sync or faulty.
 732                          * If reshape increases the number of devices, this
 733                          * section has already been recovered, else it
 734                          * almost certainly hasn't.
 735                          */
 736                         if (conf->raid_disks <= conf->previous_raid_disks)
 737                                 degraded2++;
 738         }
 739         rcu_read_unlock();
 740         if (degraded2 > degraded)
 741                 return degraded2;
 742         return degraded;
 743 }
 744
 745 static bool has_failed(struct r5conf *conf)
 746 {
 747         int degraded = conf->mddev->degraded;
 748
 749         if (test_bit(MD_BROKEN, &conf->mddev->flags))
 750                 return true;
 751
 752         if (conf->mddev->reshape_position != MaxSector)
 753                 degraded = raid5_calc_degraded(conf);
 754
 755         return degraded > conf->max_degraded;
 756 }
 757
 758 enum stripe_result {
 759         STRIPE_SUCCESS = 0,
 760         STRIPE_RETRY,
 761         STRIPE_SCHEDULE_AND_RETRY,
 762         STRIPE_FAIL,
 763 };
 764
 765 struct stripe_request_ctx {
 766         /* a reference to the last stripe_head for batching */
 767         struct stripe_head *batch_last;
 768
 769         /* first sector in the request */
 770         sector_t first_sector;
 771
 772         /* last sector in the request */
 773         sector_t last_sector;
 774
 775         /*
 776          * bitmap to track stripe sectors that have been added to stripes
 777          * add one to account for unaligned requests
 778          */
 779         DECLARE_BITMAP(sectors_to_do, RAID5_MAX_REQ_STRIPES + 1);
 780
 781         /* the request had REQ_PREFLUSH, cleared after the first stripe_head */
 782         bool do_flush;
 783 };
 784
 785 /*
 786  * Block until another thread clears R5_INACTIVE_BLOCKED or
 787  * there are fewer than 3/4 the maximum number of active stripes
 788  * and there is an inactive stripe available.
 789  */
 790 static bool is_inactive_blocked(struct r5conf *conf, int hash)
 791 {
 792         int active = atomic_read(&conf->active_stripes);
 793
 794         if (list_empty(conf->inactive_list + hash))
 795                 return false;
 796
 797         if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
 798                 return true;
 799
 800         return active < (conf->max_nr_stripes * 3 / 4);
 801 }
 802
 803 static struct stripe_head *__raid5_get_active_stripe(struct r5conf *conf,
 804                 struct stripe_request_ctx *ctx, sector_t sector,
 805                 bool previous, bool noblock, bool noquiesce)
 806 {
 807         struct stripe_head *sh;
 808         int hash = stripe_hash_locks_hash(conf, sector);
 809
 810         pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
 811
 812         spin_lock_irq(conf->hash_locks + hash);
 813
 814 retry:
 815         if (!noquiesce && conf->quiesce) {
 816                 /*
 817                  * Must release the reference to batch_last before waiting,
 818                  * on quiesce, otherwise the batch_last will hold a reference
 819                  * to a stripe and raid5_quiesce() will deadlock waiting for
 820                  * active_stripes to go to zero.
 821                  */
 822                 if (ctx && ctx->batch_last) {
 823                         raid5_release_stripe(ctx->batch_last);
 824                         ctx->batch_last = NULL;
 825                 }
 826
 827                 wait_event_lock_irq(conf->wait_for_quiescent, !conf->quiesce,
 828                                     *(conf->hash_locks + hash));
 829         }
 830
 831         sh = find_get_stripe(conf, sector, conf->generation - previous, hash);
 832         if (sh)
 833                 goto out;
 834
 835         if (test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
 836                 goto wait_for_stripe;
 837
 838         sh = get_free_stripe(conf, hash);
 839         if (sh) {
 840                 r5c_check_stripe_cache_usage(conf);
 841                 init_stripe(sh, sector, previous);
 842                 atomic_inc(&sh->count);
 843                 goto out;
 844         }
 845
 846         if (!test_bit(R5_DID_ALLOC, &conf->cache_state))
 847                 set_bit(R5_ALLOC_MORE, &conf->cache_state);
 848
 849 wait_for_stripe:
 850         if (noblock)
 851                 goto out;
 852
 853         set_bit(R5_INACTIVE_BLOCKED, &conf->cache_state);
 854         r5l_wake_reclaim(conf->log, 0);
 855         wait_event_lock_irq(conf->wait_for_stripe,
 856                             is_inactive_blocked(conf, hash),
 857                             *(conf->hash_locks + hash));
 858         clear_bit(R5_INACTIVE_BLOCKED, &conf->cache_state);
 859         goto retry;
 860
 861 out:
 862         spin_unlock_irq(conf->hash_locks + hash);
 863         return sh;
 864 }
 865
 866 struct stripe_head *raid5_get_active_stripe(struct r5conf *conf,
 867                 sector_t sector, bool previous, bool noblock, bool noquiesce)
 868 {
 869         return __raid5_get_active_stripe(conf, NULL, sector, previous, noblock,
 870                                          noquiesce);
 871 }
 872
 873 static bool is_full_stripe_write(struct stripe_head *sh)
 874 {
 875         BUG_ON(sh->overwrite_disks > (sh->disks - sh->raid_conf->max_degraded));
 876         return sh->overwrite_disks == (sh->disks - sh->raid_conf->max_degraded);
 877 }
 878
 879 static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 880                 __acquires(&sh1->stripe_lock)
 881                 __acquires(&sh2->stripe_lock)
 882 {
 883         if (sh1 > sh2) {
 884                 spin_lock_irq(&sh2->stripe_lock);
 885                 spin_lock_nested(&sh1->stripe_lock, 1);
 886         } else {
 887                 spin_lock_irq(&sh1->stripe_lock);
 888                 spin_lock_nested(&sh2->stripe_lock, 1);
 889         }
 890 }
 891
 892 static void unlock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 893                 __releases(&sh1->stripe_lock)
 894                 __releases(&sh2->stripe_lock)
 895 {
 896         spin_unlock(&sh1->stripe_lock);
 897         spin_unlock_irq(&sh2->stripe_lock);
 898 }
 899
 900 /* Only freshly new full stripe normal write stripe can be added to a batch list */
 901 static bool stripe_can_batch(struct stripe_head *sh)
 902 {
 903         struct r5conf *conf = sh->raid_conf;
 904
 905         if (raid5_has_log(conf) || raid5_has_ppl(conf))
 906                 return false;
 907         return test_bit(STRIPE_BATCH_READY, &sh->state) &&
 908                 !test_bit(STRIPE_BITMAP_PENDING, &sh->state) &&
 909                 is_full_stripe_write(sh);
 910 }
 911
 912 /* we only do back search */
 913 static void stripe_add_to_batch_list(struct r5conf *conf,
 914                 struct stripe_head *sh, struct stripe_head *last_sh)
 915 {
 916         struct stripe_head *head;
 917         sector_t head_sector, tmp_sec;
 918         int hash;
 919         int dd_idx;
 920
 921         /* Don't cross chunks, so stripe pd_idx/qd_idx is the same */
 922         tmp_sec = sh->sector;
 923         if (!sector_div(tmp_sec, conf->chunk_sectors))
 924                 return;
 925         head_sector = sh->sector - RAID5_STRIPE_SECTORS(conf);
 926
 927         if (last_sh && head_sector == last_sh->sector) {
 928                 head = last_sh;
 929                 atomic_inc(&head->count);
 930         } else {
 931                 hash = stripe_hash_locks_hash(conf, head_sector);
 932                 spin_lock_irq(conf->hash_locks + hash);
 933                 head = find_get_stripe(conf, head_sector, conf->generation,
 934                                        hash);
 935                 spin_unlock_irq(conf->hash_locks + hash);
 936                 if (!head)
 937                         return;
 938                 if (!stripe_can_batch(head))
 939                         goto out;
 940         }
 941
 942         lock_two_stripes(head, sh);
 943         /* clear_batch_ready clear the flag */
 944         if (!stripe_can_batch(head) || !stripe_can_batch(sh))
 945                 goto unlock_out;
 946
 947         if (sh->batch_head)
 948                 goto unlock_out;
 949
 950         dd_idx = 0;
 951         while (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
 952                 dd_idx++;
 953         if (head->dev[dd_idx].towrite->bi_opf != sh->dev[dd_idx].towrite->bi_opf ||
 954             bio_op(head->dev[dd_idx].towrite) != bio_op(sh->dev[dd_idx].towrite))
 955                 goto unlock_out;
 956
 957         if (head->batch_head) {
 958                 spin_lock(&head->batch_head->batch_lock);
 959                 /* This batch list is already running */
 960                 if (!stripe_can_batch(head)) {
 961                         spin_unlock(&head->batch_head->batch_lock);
 962                         goto unlock_out;
 963                 }
 964                 /*
 965                  * We must assign batch_head of this stripe within the
 966                  * batch_lock, otherwise clear_batch_ready of batch head
 967                  * stripe could clear BATCH_READY bit of this stripe and
 968                  * this stripe->batch_head doesn't get assigned, which
 969                  * could confuse clear_batch_ready for this stripe
 970                  */
 971                 sh->batch_head = head->batch_head;
 972
 973                 /*
 974                  * at this point, head's BATCH_READY could be cleared, but we
 975                  * can still add the stripe to batch list
 976                  */
 977                 list_add(&sh->batch_list, &head->batch_list);
 978                 spin_unlock(&head->batch_head->batch_lock);
 979         } else {
 980                 head->batch_head = head;
 981                 sh->batch_head = head->batch_head;
 982                 spin_lock(&head->batch_lock);
 983                 list_add_tail(&sh->batch_list, &head->batch_list);
 984                 spin_unlock(&head->batch_lock);
 985         }
 986
 987         if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 988                 if (atomic_dec_return(&conf->preread_active_stripes)
 989                     < IO_THRESHOLD)
 990                         md_wakeup_thread(conf->mddev->thread);
 991
 992         if (test_and_clear_bit(STRIPE_BIT_DELAY, &sh->state)) {
 993                 int seq = sh->bm_seq;
 994                 if (test_bit(STRIPE_BIT_DELAY, &sh->batch_head->state) &&
 995                     sh->batch_head->bm_seq > seq)
 996                         seq = sh->batch_head->bm_seq;
 997                 set_bit(STRIPE_BIT_DELAY, &sh->batch_head->state);
 998                 sh->batch_head->bm_seq = seq;
 999         }
1000
1001         atomic_inc(&sh->count);
1002 unlock_out:
1003         unlock_two_stripes(head, sh);
1004 out:
1005         raid5_release_stripe(head);
1006 }
1007
1008 /* Determine if 'data_offset' or 'new_data_offset' should be used
1009  * in this stripe_head.
1010  */
1011 static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
1012 {
1013         sector_t progress = conf->reshape_progress;
1014         /* Need a memory barrier to make sure we see the value
1015          * of conf->generation, or ->data_offset that was set before
1016          * reshape_progress was updated.
1017          */
1018         smp_rmb();
1019         if (progress == MaxSector)
1020                 return 0;
1021         if (sh->generation == conf->generation - 1)
1022                 return 0;
1023         /* We are in a reshape, and this is a new-generation stripe,
1024          * so use new_data_offset.
1025          */
1026         return 1;
1027 }
1028
1029 static void dispatch_bio_list(struct bio_list *tmp)
1030 {
1031         struct bio *bio;
1032
1033         while ((bio = bio_list_pop(tmp)))
1034                 submit_bio_noacct(bio);
1035 }
1036
1037 static int cmp_stripe(void *priv, const struct list_head *a,
1038                       const struct list_head *b)
1039 {
1040         const struct r5pending_data *da = list_entry(a,
1041                                 struct r5pending_data, sibling);
1042         const struct r5pending_data *db = list_entry(b,
1043                                 struct r5pending_data, sibling);
1044         if (da->sector > db->sector)
1045                 return 1;
1046         if (da->sector < db->sector)
1047                 return -1;
1048         return 0;
1049 }
1050
1051 static void dispatch_defer_bios(struct r5conf *conf, int target,
1052                                 struct bio_list *list)
1053 {
1054         struct r5pending_data *data;
1055         struct list_head *first, *next = NULL;
1056         int cnt = 0;
1057
1058         if (conf->pending_data_cnt == 0)
1059                 return;
1060
1061         list_sort(NULL, &conf->pending_list, cmp_stripe);
1062
1063         first = conf->pending_list.next;
1064
1065         /* temporarily move the head */
1066         if (conf->next_pending_data)
1067                 list_move_tail(&conf->pending_list,
1068                                 &conf->next_pending_data->sibling);
1069
1070         while (!list_empty(&conf->pending_list)) {
1071                 data = list_first_entry(&conf->pending_list,
1072                         struct r5pending_data, sibling);
1073                 if (&data->sibling == first)
1074                         first = data->sibling.next;
1075                 next = data->sibling.next;
1076
1077                 bio_list_merge(list, &data->bios);
1078                 list_move(&data->sibling, &conf->free_list);
1079                 cnt++;
1080                 if (cnt >= target)
1081                         break;
1082         }
1083         conf->pending_data_cnt -= cnt;
1084         BUG_ON(conf->pending_data_cnt < 0 || cnt < target);
1085
1086         if (next != &conf->pending_list)
1087                 conf->next_pending_data = list_entry(next,
1088                                 struct r5pending_data, sibling);
1089         else
1090                 conf->next_pending_data = NULL;
1091         /* list isn't empty */
1092         if (first != &conf->pending_list)
1093                 list_move_tail(&conf->pending_list, first);
1094 }
1095
1096 static void flush_deferred_bios(struct r5conf *conf)
1097 {
1098         struct bio_list tmp = BIO_EMPTY_LIST;
1099
1100         if (conf->pending_data_cnt == 0)
1101                 return;
1102
1103         spin_lock(&conf->pending_bios_lock);
1104         dispatch_defer_bios(conf, conf->pending_data_cnt, &tmp);
1105         BUG_ON(conf->pending_data_cnt != 0);
1106         spin_unlock(&conf->pending_bios_lock);
1107
1108         dispatch_bio_list(&tmp);
1109 }
1110
1111 static void defer_issue_bios(struct r5conf *conf, sector_t sector,
1112                                 struct bio_list *bios)
1113 {
1114         struct bio_list tmp = BIO_EMPTY_LIST;
1115         struct r5pending_data *ent;
1116
1117         spin_lock(&conf->pending_bios_lock);
1118         ent = list_first_entry(&conf->free_list, struct r5pending_data,
1119                                                         sibling);
1120         list_move_tail(&ent->sibling, &conf->pending_list);
1121         ent->sector = sector;
1122         bio_list_init(&ent->bios);
1123         bio_list_merge(&ent->bios, bios);
1124         conf->pending_data_cnt++;
1125         if (conf->pending_data_cnt >= PENDING_IO_MAX)
1126                 dispatch_defer_bios(conf, PENDING_IO_ONE_FLUSH, &tmp);
1127
1128         spin_unlock(&conf->pending_bios_lock);
1129
1130         dispatch_bio_list(&tmp);
1131 }
1132
1133 static void
1134 raid5_end_read_request(struct bio *bi);
1135 static void
1136 raid5_end_write_request(struct bio *bi);
1137
1138 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
1139 {
1140         struct r5conf *conf = sh->raid_conf;
1141         int i, disks = sh->disks;
1142         struct stripe_head *head_sh = sh;
1143         struct bio_list pending_bios = BIO_EMPTY_LIST;
1144         struct r5dev *dev;
1145         bool should_defer;
1146
1147         might_sleep();
1148
1149         if (log_stripe(sh, s) == 0)
1150                 return;
1151
1152         should_defer = conf->batch_bio_dispatch && conf->group_cnt;
1153
1154         for (i = disks; i--; ) {
1155                 enum req_op op;
1156                 blk_opf_t op_flags = 0;
1157                 int replace_only = 0;
1158                 struct bio *bi, *rbi;
1159                 struct md_rdev *rdev, *rrdev = NULL;
1160
1161                 sh = head_sh;
1162                 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
1163                         op = REQ_OP_WRITE;
1164                         if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
1165                                 op_flags = REQ_FUA;
1166                         if (test_bit(R5_Discard, &sh->dev[i].flags))
1167                                 op = REQ_OP_DISCARD;
1168                 } else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1169                         op = REQ_OP_READ;
1170                 else if (test_and_clear_bit(R5_WantReplace,
1171                                             &sh->dev[i].flags)) {
1172                         op = REQ_OP_WRITE;
1173                         replace_only = 1;
1174                 } else
1175                         continue;
1176                 if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
1177                         op_flags |= REQ_SYNC;
1178
1179 again:
1180                 dev = &sh->dev[i];
1181                 bi = &dev->req;
1182                 rbi = &dev->rreq; /* For writing to replacement */
1183
1184                 rcu_read_lock();
1185                 rrdev = rcu_dereference(conf->disks[i].replacement);
1186                 smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
1187                 rdev = rcu_dereference(conf->disks[i].rdev);
1188                 if (!rdev) {
1189                         rdev = rrdev;
1190                         rrdev = NULL;
1191                 }
1192                 if (op_is_write(op)) {
1193                         if (replace_only)
1194                                 rdev = NULL;
1195                         if (rdev == rrdev)
1196                                 /* We raced and saw duplicates */
1197                                 rrdev = NULL;
1198                 } else {
1199                         if (test_bit(R5_ReadRepl, &head_sh->dev[i].flags) && rrdev)
1200                                 rdev = rrdev;
1201                         rrdev = NULL;
1202                 }
1203
1204                 if (rdev && test_bit(Faulty, &rdev->flags))
1205                         rdev = NULL;
1206                 if (rdev)
1207                         atomic_inc(&rdev->nr_pending);
1208                 if (rrdev && test_bit(Faulty, &rrdev->flags))
1209                         rrdev = NULL;
1210                 if (rrdev)
1211                         atomic_inc(&rrdev->nr_pending);
1212                 rcu_read_unlock();
1213
1214                 /* We have already checked bad blocks for reads.  Now
1215                  * need to check for writes.  We never accept write errors
1216                  * on the replacement, so we don't to check rrdev.
1217                  */
1218                 while (op_is_write(op) && rdev &&
1219                        test_bit(WriteErrorSeen, &rdev->flags)) {
1220                         sector_t first_bad;
1221                         int bad_sectors;
1222                         int bad = is_badblock(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf),
1223                                               &first_bad, &bad_sectors);
1224                         if (!bad)
1225                                 break;
1226
1227                         if (bad < 0) {
1228                                 set_bit(BlockedBadBlocks, &rdev->flags);
1229                                 if (!conf->mddev->external &&
1230                                     conf->mddev->sb_flags) {
1231                                         /* It is very unlikely, but we might
1232                                          * still need to write out the
1233                                          * bad block log - better give it
1234                                          * a chance*/
1235                                         md_check_recovery(conf->mddev);
1236                                 }
1237                                 /*
1238                                  * Because md_wait_for_blocked_rdev
1239                                  * will dec nr_pending, we must
1240                                  * increment it first.
1241                                  */
1242                                 atomic_inc(&rdev->nr_pending);
1243                                 md_wait_for_blocked_rdev(rdev, conf->mddev);
1244                         } else {
1245                                 /* Acknowledged bad block - skip the write */
1246                                 rdev_dec_pending(rdev, conf->mddev);
1247                                 rdev = NULL;
1248                         }
1249                 }
1250
1251                 if (rdev) {
1252                         if (s->syncing || s->expanding || s->expanded
1253                             || s->replacing)
1254                                 md_sync_acct(rdev->bdev, RAID5_STRIPE_SECTORS(conf));
1255
1256                         set_bit(STRIPE_IO_STARTED, &sh->state);
1257
1258                         bio_init(bi, rdev->bdev, &dev->vec, 1, op | op_flags);
1259                         bi->bi_end_io = op_is_write(op)
1260                                 ? raid5_end_write_request
1261                                 : raid5_end_read_request;
1262                         bi->bi_private = sh;
1263
1264                         pr_debug("%s: for %llu schedule op %d on disc %d\n",
1265                                 __func__, (unsigned long long)sh->sector,
1266                                 bi->bi_opf, i);
1267                         atomic_inc(&sh->count);
1268                         if (sh != head_sh)
1269                                 atomic_inc(&head_sh->count);
1270                         if (use_new_offset(conf, sh))
1271                                 bi->bi_iter.bi_sector = (sh->sector
1272                                                  + rdev->new_data_offset);
1273                         else
1274                                 bi->bi_iter.bi_sector = (sh->sector
1275                                                  + rdev->data_offset);
1276                         if (test_bit(R5_ReadNoMerge, &head_sh->dev[i].flags))
1277                                 bi->bi_opf |= REQ_NOMERGE;
1278
1279                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1280                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1281
1282                         if (!op_is_write(op) &&
1283                             test_bit(R5_InJournal, &sh->dev[i].flags))
1284                                 /*
1285                                  * issuing read for a page in journal, this
1286                                  * must be preparing for prexor in rmw; read
1287                                  * the data into orig_page
1288                                  */
1289                                 sh->dev[i].vec.bv_page = sh->dev[i].orig_page;
1290                         else
1291                                 sh->dev[i].vec.bv_page = sh->dev[i].page;
1292                         bi->bi_vcnt = 1;
1293                         bi->bi_io_vec[0].bv_len = RAID5_STRIPE_SIZE(conf);
1294                         bi->bi_io_vec[0].bv_offset = sh->dev[i].offset;
1295                         bi->bi_iter.bi_size = RAID5_STRIPE_SIZE(conf);
1296                         /*
1297                          * If this is discard request, set bi_vcnt 0. We don't
1298                          * want to confuse SCSI because SCSI will replace payload
1299                          */
1300                         if (op == REQ_OP_DISCARD)
1301                                 bi->bi_vcnt = 0;
1302                         if (rrdev)
1303                                 set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
1304
1305                         if (conf->mddev->gendisk)
1306                                 trace_block_bio_remap(bi,
1307                                                 disk_devt(conf->mddev->gendisk),
1308                                                 sh->dev[i].sector);
1309                         if (should_defer && op_is_write(op))
1310                                 bio_list_add(&pending_bios, bi);
1311                         else
1312                                 submit_bio_noacct(bi);
1313                 }
1314                 if (rrdev) {
1315                         if (s->syncing || s->expanding || s->expanded
1316                             || s->replacing)
1317                                 md_sync_acct(rrdev->bdev, RAID5_STRIPE_SECTORS(conf));
1318
1319                         set_bit(STRIPE_IO_STARTED, &sh->state);
1320
1321                         bio_init(rbi, rrdev->bdev, &dev->rvec, 1, op | op_flags);
1322                         BUG_ON(!op_is_write(op));
1323                         rbi->bi_end_io = raid5_end_write_request;
1324                         rbi->bi_private = sh;
1325
1326                         pr_debug("%s: for %llu schedule op %d on "
1327                                  "replacement disc %d\n",
1328                                 __func__, (unsigned long long)sh->sector,
1329                                 rbi->bi_opf, i);
1330                         atomic_inc(&sh->count);
1331                         if (sh != head_sh)
1332                                 atomic_inc(&head_sh->count);
1333                         if (use_new_offset(conf, sh))
1334                                 rbi->bi_iter.bi_sector = (sh->sector
1335                                                   + rrdev->new_data_offset);
1336                         else
1337                                 rbi->bi_iter.bi_sector = (sh->sector
1338                                                   + rrdev->data_offset);
1339                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1340                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1341                         sh->dev[i].rvec.bv_page = sh->dev[i].page;
1342                         rbi->bi_vcnt = 1;
1343                         rbi->bi_io_vec[0].bv_len = RAID5_STRIPE_SIZE(conf);
1344                         rbi->bi_io_vec[0].bv_offset = sh->dev[i].offset;
1345                         rbi->bi_iter.bi_size = RAID5_STRIPE_SIZE(conf);
1346                         /*
1347                          * If this is discard request, set bi_vcnt 0. We don't
1348                          * want to confuse SCSI because SCSI will replace payload
1349                          */
1350                         if (op == REQ_OP_DISCARD)
1351                                 rbi->bi_vcnt = 0;
1352                         if (conf->mddev->gendisk)
1353                                 trace_block_bio_remap(rbi,
1354                                                 disk_devt(conf->mddev->gendisk),
1355                                                 sh->dev[i].sector);
1356                         if (should_defer && op_is_write(op))
1357                                 bio_list_add(&pending_bios, rbi);
1358                         else
1359                                 submit_bio_noacct(rbi);
1360                 }
1361                 if (!rdev && !rrdev) {
1362                         if (op_is_write(op))
1363                                 set_bit(STRIPE_DEGRADED, &sh->state);
1364                         pr_debug("skip op %d on disc %d for sector %llu\n",
1365                                 bi->bi_opf, i, (unsigned long long)sh->sector);
1366                         clear_bit(R5_LOCKED, &sh->dev[i].flags);
1367                         set_bit(STRIPE_HANDLE, &sh->state);
1368                 }
1369
1370                 if (!head_sh->batch_head)
1371                         continue;
1372                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1373                                       batch_list);
1374                 if (sh != head_sh)
1375                         goto again;
1376         }
1377
1378         if (should_defer && !bio_list_empty(&pending_bios))
1379                 defer_issue_bios(conf, head_sh->sector, &pending_bios);
1380 }
1381
1382 static struct dma_async_tx_descriptor *
1383 async_copy_data(int frombio, struct bio *bio, struct page **page,
1384         unsigned int poff, sector_t sector, struct dma_async_tx_descriptor *tx,
1385         struct stripe_head *sh, int no_skipcopy)
1386 {
1387         struct bio_vec bvl;
1388         struct bvec_iter iter;
1389         struct page *bio_page;
1390         int page_offset;
1391         struct async_submit_ctl submit;
1392         enum async_tx_flags flags = 0;
1393         struct r5conf *conf = sh->raid_conf;
1394
1395         if (bio->bi_iter.bi_sector >= sector)
1396                 page_offset = (signed)(bio->bi_iter.bi_sector - sector) * 512;
1397         else
1398                 page_offset = (signed)(sector - bio->bi_iter.bi_sector) * -512;
1399
1400         if (frombio)
1401                 flags |= ASYNC_TX_FENCE;
1402         init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
1403
1404         bio_for_each_segment(bvl, bio, iter) {
1405                 int len = bvl.bv_len;
1406                 int clen;
1407                 int b_offset = 0;
1408
1409                 if (page_offset < 0) {
1410                         b_offset = -page_offset;
1411                         page_offset += b_offset;
1412                         len -= b_offset;
1413                 }
1414
1415                 if (len > 0 && page_offset + len > RAID5_STRIPE_SIZE(conf))
1416                         clen = RAID5_STRIPE_SIZE(conf) - page_offset;
1417                 else
1418                         clen = len;
1419
1420                 if (clen > 0) {
1421                         b_offset += bvl.bv_offset;
1422                         bio_page = bvl.bv_page;
1423                         if (frombio) {
1424                                 if (conf->skip_copy &&
1425                                     b_offset == 0 && page_offset == 0 &&
1426                                     clen == RAID5_STRIPE_SIZE(conf) &&
1427                                     !no_skipcopy)
1428                                         *page = bio_page;
1429                                 else
1430                                         tx = async_memcpy(*page, bio_page, page_offset + poff,
1431                                                   b_offset, clen, &submit);
1432                         } else
1433                                 tx = async_memcpy(bio_page, *page, b_offset,
1434                                                   page_offset + poff, clen, &submit);
1435                 }
1436                 /* chain the operations */
1437                 submit.depend_tx = tx;
1438
1439                 if (clen < len) /* hit end of page */
1440                         break;
1441                 page_offset +=  len;
1442         }
1443
1444         return tx;
1445 }
1446
1447 static void ops_complete_biofill(void *stripe_head_ref)
1448 {
1449         struct stripe_head *sh = stripe_head_ref;
1450         int i;
1451         struct r5conf *conf = sh->raid_conf;
1452
1453         pr_debug("%s: stripe %llu\n", __func__,
1454                 (unsigned long long)sh->sector);
1455
1456         /* clear completed biofills */
1457         for (i = sh->disks; i--; ) {
1458                 struct r5dev *dev = &sh->dev[i];
1459
1460                 /* acknowledge completion of a biofill operation */
1461                 /* and check if we need to reply to a read request,
1462                  * new R5_Wantfill requests are held off until
1463                  * !STRIPE_BIOFILL_RUN
1464                  */
1465                 if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
1466                         struct bio *rbi, *rbi2;
1467
1468                         BUG_ON(!dev->read);
1469                         rbi = dev->read;
1470                         dev->read = NULL;
1471                         while (rbi && rbi->bi_iter.bi_sector <
1472                                 dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1473                                 rbi2 = r5_next_bio(conf, rbi, dev->sector);
1474                                 bio_endio(rbi);
1475                                 rbi = rbi2;
1476                         }
1477                 }
1478         }
1479         clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
1480
1481         set_bit(STRIPE_HANDLE, &sh->state);
1482         raid5_release_stripe(sh);
1483 }
1484
1485 static void ops_run_biofill(struct stripe_head *sh)
1486 {
1487         struct dma_async_tx_descriptor *tx = NULL;
1488         struct async_submit_ctl submit;
1489         int i;
1490         struct r5conf *conf = sh->raid_conf;
1491
1492         BUG_ON(sh->batch_head);
1493         pr_debug("%s: stripe %llu\n", __func__,
1494                 (unsigned long long)sh->sector);
1495
1496         for (i = sh->disks; i--; ) {
1497                 struct r5dev *dev = &sh->dev[i];
1498                 if (test_bit(R5_Wantfill, &dev->flags)) {
1499                         struct bio *rbi;
1500                         spin_lock_irq(&sh->stripe_lock);
1501                         dev->read = rbi = dev->toread;
1502                         dev->toread = NULL;
1503                         spin_unlock_irq(&sh->stripe_lock);
1504                         while (rbi && rbi->bi_iter.bi_sector <
1505                                 dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1506                                 tx = async_copy_data(0, rbi, &dev->page,
1507                                                      dev->offset,
1508                                                      dev->sector, tx, sh, 0);
1509                                 rbi = r5_next_bio(conf, rbi, dev->sector);
1510                         }
1511                 }
1512         }
1513
1514         atomic_inc(&sh->count);
1515         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
1516         async_trigger_callback(&submit);
1517 }
1518
1519 static void mark_target_uptodate(struct stripe_head *sh, int target)
1520 {
1521         struct r5dev *tgt;
1522
1523         if (target < 0)
1524                 return;
1525
1526         tgt = &sh->dev[target];
1527         set_bit(R5_UPTODATE, &tgt->flags);
1528         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1529         clear_bit(R5_Wantcompute, &tgt->flags);
1530 }
1531
1532 static void ops_complete_compute(void *stripe_head_ref)
1533 {
1534         struct stripe_head *sh = stripe_head_ref;
1535
1536         pr_debug("%s: stripe %llu\n", __func__,
1537                 (unsigned long long)sh->sector);
1538
1539         /* mark the computed target(s) as uptodate */
1540         mark_target_uptodate(sh, sh->ops.target);
1541         mark_target_uptodate(sh, sh->ops.target2);
1542
1543         clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
1544         if (sh->check_state == check_state_compute_run)
1545                 sh->check_state = check_state_compute_result;
1546         set_bit(STRIPE_HANDLE, &sh->state);
1547         raid5_release_stripe(sh);
1548 }
1549
1550 /* return a pointer to the address conversion region of the scribble buffer */
1551 static struct page **to_addr_page(struct raid5_percpu *percpu, int i)
1552 {
1553         return percpu->scribble + i * percpu->scribble_obj_size;
1554 }
1555
1556 /* return a pointer to the address conversion region of the scribble buffer */
1557 static addr_conv_t *to_addr_conv(struct stripe_head *sh,
1558                                  struct raid5_percpu *percpu, int i)
1559 {
1560         return (void *) (to_addr_page(percpu, i) + sh->disks + 2);
1561 }
1562
1563 /*
1564  * Return a pointer to record offset address.
1565  */
1566 static unsigned int *
1567 to_addr_offs(struct stripe_head *sh, struct raid5_percpu *percpu)
1568 {
1569         return (unsigned int *) (to_addr_conv(sh, percpu, 0) + sh->disks + 2);
1570 }
1571
1572 static struct dma_async_tx_descriptor *
1573 ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
1574 {
1575         int disks = sh->disks;
1576         struct page **xor_srcs = to_addr_page(percpu, 0);
1577         unsigned int *off_srcs = to_addr_offs(sh, percpu);
1578         int target = sh->ops.target;
1579         struct r5dev *tgt = &sh->dev[target];
1580         struct page *xor_dest = tgt->page;
1581         unsigned int off_dest = tgt->offset;
1582         int count = 0;
1583         struct dma_async_tx_descriptor *tx;
1584         struct async_submit_ctl submit;
1585         int i;
1586
1587         BUG_ON(sh->batch_head);
1588
1589         pr_debug("%s: stripe %llu block: %d\n",
1590                 __func__, (unsigned long long)sh->sector, target);
1591         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1592
1593         for (i = disks; i--; ) {
1594                 if (i != target) {
1595                         off_srcs[count] = sh->dev[i].offset;
1596                         xor_srcs[count++] = sh->dev[i].page;
1597                 }
1598         }
1599
1600         atomic_inc(&sh->count);
1601
1602         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
1603                           ops_complete_compute, sh, to_addr_conv(sh, percpu, 0));
1604         if (unlikely(count == 1))
1605                 tx = async_memcpy(xor_dest, xor_srcs[0], off_dest, off_srcs[0],
1606                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1607         else
1608                 tx = async_xor_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
1609                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1610
1611         return tx;
1612 }
1613
1614 /* set_syndrome_sources - populate source buffers for gen_syndrome
1615  * @srcs - (struct page *) array of size sh->disks
1616  * @offs - (unsigned int) array of offset for each page
1617  * @sh - stripe_head to parse
1618  *
1619  * Populates srcs in proper layout order for the stripe and returns the
1620  * 'count' of sources to be used in a call to async_gen_syndrome.  The P
1621  * destination buffer is recorded in srcs[count] and the Q destination
1622  * is recorded in srcs[count+1]].
1623  */
1624 static int set_syndrome_sources(struct page **srcs,
1625                                 unsigned int *offs,
1626                                 struct stripe_head *sh,
1627                                 int srctype)
1628 {
1629         int disks = sh->disks;
1630         int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
1631         int d0_idx = raid6_d0(sh);
1632         int count;
1633         int i;
1634
1635         for (i = 0; i < disks; i++)
1636                 srcs[i] = NULL;
1637
1638         count = 0;
1639         i = d0_idx;
1640         do {
1641                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1642                 struct r5dev *dev = &sh->dev[i];
1643
1644                 if (i == sh->qd_idx || i == sh->pd_idx ||
1645                     (srctype == SYNDROME_SRC_ALL) ||
1646                     (srctype == SYNDROME_SRC_WANT_DRAIN &&
1647                      (test_bit(R5_Wantdrain, &dev->flags) ||
1648                       test_bit(R5_InJournal, &dev->flags))) ||
1649                     (srctype == SYNDROME_SRC_WRITTEN &&
1650                      (dev->written ||
1651                       test_bit(R5_InJournal, &dev->flags)))) {
1652                         if (test_bit(R5_InJournal, &dev->flags))
1653                                 srcs[slot] = sh->dev[i].orig_page;
1654                         else
1655                                 srcs[slot] = sh->dev[i].page;
1656                         /*
1657                          * For R5_InJournal, PAGE_SIZE must be 4KB and will
1658                          * not shared page. In that case, dev[i].offset
1659                          * is 0.
1660                          */
1661                         offs[slot] = sh->dev[i].offset;
1662                 }
1663                 i = raid6_next_disk(i, disks);
1664         } while (i != d0_idx);
1665
1666         return syndrome_disks;
1667 }
1668
1669 static struct dma_async_tx_descriptor *
1670 ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
1671 {
1672         int disks = sh->disks;
1673         struct page **blocks = to_addr_page(percpu, 0);
1674         unsigned int *offs = to_addr_offs(sh, percpu);
1675         int target;
1676         int qd_idx = sh->qd_idx;
1677         struct dma_async_tx_descriptor *tx;
1678         struct async_submit_ctl submit;
1679         struct r5dev *tgt;
1680         struct page *dest;
1681         unsigned int dest_off;
1682         int i;
1683         int count;
1684
1685         BUG_ON(sh->batch_head);
1686         if (sh->ops.target < 0)
1687                 target = sh->ops.target2;
1688         else if (sh->ops.target2 < 0)
1689                 target = sh->ops.target;
1690         else
1691                 /* we should only have one valid target */
1692                 BUG();
1693         BUG_ON(target < 0);
1694         pr_debug("%s: stripe %llu block: %d\n",
1695                 __func__, (unsigned long long)sh->sector, target);
1696
1697         tgt = &sh->dev[target];
1698         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1699         dest = tgt->page;
1700         dest_off = tgt->offset;
1701
1702         atomic_inc(&sh->count);
1703
1704         if (target == qd_idx) {
1705                 count = set_syndrome_sources(blocks, offs, sh, SYNDROME_SRC_ALL);
1706                 blocks[count] = NULL; /* regenerating p is not necessary */
1707                 BUG_ON(blocks[count+1] != dest); /* q should already be set */
1708                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1709                                   ops_complete_compute, sh,
1710                                   to_addr_conv(sh, percpu, 0));
1711                 tx = async_gen_syndrome(blocks, offs, count+2,
1712                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1713         } else {
1714                 /* Compute any data- or p-drive using XOR */
1715                 count = 0;
1716                 for (i = disks; i-- ; ) {
1717                         if (i == target || i == qd_idx)
1718                                 continue;
1719                         offs[count] = sh->dev[i].offset;
1720                         blocks[count++] = sh->dev[i].page;
1721                 }
1722
1723                 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1724                                   NULL, ops_complete_compute, sh,
1725                                   to_addr_conv(sh, percpu, 0));
1726                 tx = async_xor_offs(dest, dest_off, blocks, offs, count,
1727                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1728         }
1729
1730         return tx;
1731 }
1732
1733 static struct dma_async_tx_descriptor *
1734 ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
1735 {
1736         int i, count, disks = sh->disks;
1737         int syndrome_disks = sh->ddf_layout ? disks : disks-2;
1738         int d0_idx = raid6_d0(sh);
1739         int faila = -1, failb = -1;
1740         int target = sh->ops.target;
1741         int target2 = sh->ops.target2;
1742         struct r5dev *tgt = &sh->dev[target];
1743         struct r5dev *tgt2 = &sh->dev[target2];
1744         struct dma_async_tx_descriptor *tx;
1745         struct page **blocks = to_addr_page(percpu, 0);
1746         unsigned int *offs = to_addr_offs(sh, percpu);
1747         struct async_submit_ctl submit;
1748
1749         BUG_ON(sh->batch_head);
1750         pr_debug("%s: stripe %llu block1: %d block2: %d\n",
1751                  __func__, (unsigned long long)sh->sector, target, target2);
1752         BUG_ON(target < 0 || target2 < 0);
1753         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1754         BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
1755
1756         /* we need to open-code set_syndrome_sources to handle the
1757          * slot number conversion for 'faila' and 'failb'
1758          */
1759         for (i = 0; i < disks ; i++) {
1760                 offs[i] = 0;
1761                 blocks[i] = NULL;
1762         }
1763         count = 0;
1764         i = d0_idx;
1765         do {
1766                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1767
1768                 offs[slot] = sh->dev[i].offset;
1769                 blocks[slot] = sh->dev[i].page;
1770
1771                 if (i == target)
1772                         faila = slot;
1773                 if (i == target2)
1774                         failb = slot;
1775                 i = raid6_next_disk(i, disks);
1776         } while (i != d0_idx);
1777
1778         BUG_ON(faila == failb);
1779         if (failb < faila)
1780                 swap(faila, failb);
1781         pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
1782                  __func__, (unsigned long long)sh->sector, faila, failb);
1783
1784         atomic_inc(&sh->count);
1785
1786         if (failb == syndrome_disks+1) {
1787                 /* Q disk is one of the missing disks */
1788                 if (faila == syndrome_disks) {
1789                         /* Missing P+Q, just recompute */
1790                         init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1791                                           ops_complete_compute, sh,
1792                                           to_addr_conv(sh, percpu, 0));
1793                         return async_gen_syndrome(blocks, offs, syndrome_disks+2,
1794                                                   RAID5_STRIPE_SIZE(sh->raid_conf),
1795                                                   &submit);
1796                 } else {
1797                         struct page *dest;
1798                         unsigned int dest_off;
1799                         int data_target;
1800                         int qd_idx = sh->qd_idx;
1801
1802                         /* Missing D+Q: recompute D from P, then recompute Q */
1803                         if (target == qd_idx)
1804                                 data_target = target2;
1805                         else
1806                                 data_target = target;
1807
1808                         count = 0;
1809                         for (i = disks; i-- ; ) {
1810                                 if (i == data_target || i == qd_idx)
1811                                         continue;
1812                                 offs[count] = sh->dev[i].offset;
1813                                 blocks[count++] = sh->dev[i].page;
1814                         }
1815                         dest = sh->dev[data_target].page;
1816                         dest_off = sh->dev[data_target].offset;
1817                         init_async_submit(&submit,
1818                                           ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1819                                           NULL, NULL, NULL,
1820                                           to_addr_conv(sh, percpu, 0));
1821                         tx = async_xor_offs(dest, dest_off, blocks, offs, count,
1822                                        RAID5_STRIPE_SIZE(sh->raid_conf),
1823                                        &submit);
1824
1825                         count = set_syndrome_sources(blocks, offs, sh, SYNDROME_SRC_ALL);
1826                         init_async_submit(&submit, ASYNC_TX_FENCE, tx,
1827                                           ops_complete_compute, sh,
1828                                           to_addr_conv(sh, percpu, 0));
1829                         return async_gen_syndrome(blocks, offs, count+2,
1830                                                   RAID5_STRIPE_SIZE(sh->raid_conf),
1831                                                   &submit);
1832                 }
1833         } else {
1834                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1835                                   ops_complete_compute, sh,
1836                                   to_addr_conv(sh, percpu, 0));
1837                 if (failb == syndrome_disks) {
1838                         /* We're missing D+P. */
1839                         return async_raid6_datap_recov(syndrome_disks+2,
1840                                                 RAID5_STRIPE_SIZE(sh->raid_conf),
1841                                                 faila,
1842                                                 blocks, offs, &submit);
1843                 } else {
1844                         /* We're missing D+D. */
1845                         return async_raid6_2data_recov(syndrome_disks+2,
1846                                                 RAID5_STRIPE_SIZE(sh->raid_conf),
1847                                                 faila, failb,
1848                                                 blocks, offs, &submit);
1849                 }
1850         }
1851 }
1852
1853 static void ops_complete_prexor(void *stripe_head_ref)
1854 {
1855         struct stripe_head *sh = stripe_head_ref;
1856
1857         pr_debug("%s: stripe %llu\n", __func__,
1858                 (unsigned long long)sh->sector);
1859
1860         if (r5c_is_writeback(sh->raid_conf->log))
1861                 /*
1862                  * raid5-cache write back uses orig_page during prexor.
1863                  * After prexor, it is time to free orig_page
1864                  */
1865                 r5c_release_extra_page(sh);
1866 }
1867
1868 static struct dma_async_tx_descriptor *
1869 ops_run_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
1870                 struct dma_async_tx_descriptor *tx)
1871 {
1872         int disks = sh->disks;
1873         struct page **xor_srcs = to_addr_page(percpu, 0);
1874         unsigned int *off_srcs = to_addr_offs(sh, percpu);
1875         int count = 0, pd_idx = sh->pd_idx, i;
1876         struct async_submit_ctl submit;
1877
1878         /* existing parity data subtracted */
1879         unsigned int off_dest = off_srcs[count] = sh->dev[pd_idx].offset;
1880         struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1881
1882         BUG_ON(sh->batch_head);
1883         pr_debug("%s: stripe %llu\n", __func__,
1884                 (unsigned long long)sh->sector);
1885
1886         for (i = disks; i--; ) {
1887                 struct r5dev *dev = &sh->dev[i];
1888                 /* Only process blocks that are known to be uptodate */
1889                 if (test_bit(R5_InJournal, &dev->flags)) {
1890                         /*
1891                          * For this case, PAGE_SIZE must be equal to 4KB and
1892                          * page offset is zero.
1893                          */
1894                         off_srcs[count] = dev->offset;
1895                         xor_srcs[count++] = dev->orig_page;
1896                 } else if (test_bit(R5_Wantdrain, &dev->flags)) {
1897                         off_srcs[count] = dev->offset;
1898                         xor_srcs[count++] = dev->page;
1899                 }
1900         }
1901
1902         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1903                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1904         tx = async_xor_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
1905                         RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1906
1907         return tx;
1908 }
1909
1910 static struct dma_async_tx_descriptor *
1911 ops_run_prexor6(struct stripe_head *sh, struct raid5_percpu *percpu,
1912                 struct dma_async_tx_descriptor *tx)
1913 {
1914         struct page **blocks = to_addr_page(percpu, 0);
1915         unsigned int *offs = to_addr_offs(sh, percpu);
1916         int count;
1917         struct async_submit_ctl submit;
1918
1919         pr_debug("%s: stripe %llu\n", __func__,
1920                 (unsigned long long)sh->sector);
1921
1922         count = set_syndrome_sources(blocks, offs, sh, SYNDROME_SRC_WANT_DRAIN);
1923
1924         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_PQ_XOR_DST, tx,
1925                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1926         tx = async_gen_syndrome(blocks, offs, count+2,
1927                         RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1928
1929         return tx;
1930 }
1931
1932 static struct dma_async_tx_descriptor *
1933 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1934 {
1935         struct r5conf *conf = sh->raid_conf;
1936         int disks = sh->disks;
1937         int i;
1938         struct stripe_head *head_sh = sh;
1939
1940         pr_debug("%s: stripe %llu\n", __func__,
1941                 (unsigned long long)sh->sector);
1942
1943         for (i = disks; i--; ) {
1944                 struct r5dev *dev;
1945                 struct bio *chosen;
1946
1947                 sh = head_sh;
1948                 if (test_and_clear_bit(R5_Wantdrain, &head_sh->dev[i].flags)) {
1949                         struct bio *wbi;
1950
1951 again:
1952                         dev = &sh->dev[i];
1953                         /*
1954                          * clear R5_InJournal, so when rewriting a page in
1955                          * journal, it is not skipped by r5l_log_stripe()
1956                          */
1957                         clear_bit(R5_InJournal, &dev->flags);
1958                         spin_lock_irq(&sh->stripe_lock);
1959                         chosen = dev->towrite;
1960                         dev->towrite = NULL;
1961                         sh->overwrite_disks = 0;
1962                         BUG_ON(dev->written);
1963                         wbi = dev->written = chosen;
1964                         spin_unlock_irq(&sh->stripe_lock);
1965                         WARN_ON(dev->page != dev->orig_page);
1966
1967                         while (wbi && wbi->bi_iter.bi_sector <
1968                                 dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1969                                 if (wbi->bi_opf & REQ_FUA)
1970                                         set_bit(R5_WantFUA, &dev->flags);
1971                                 if (wbi->bi_opf & REQ_SYNC)
1972                                         set_bit(R5_SyncIO, &dev->flags);
1973                                 if (bio_op(wbi) == REQ_OP_DISCARD)
1974                                         set_bit(R5_Discard, &dev->flags);
1975                                 else {
1976                                         tx = async_copy_data(1, wbi, &dev->page,
1977                                                              dev->offset,
1978                                                              dev->sector, tx, sh,
1979                                                              r5c_is_writeback(conf->log));
1980                                         if (dev->page != dev->orig_page &&
1981                                             !r5c_is_writeback(conf->log)) {
1982                                                 set_bit(R5_SkipCopy, &dev->flags);
1983                                                 clear_bit(R5_UPTODATE, &dev->flags);
1984                                                 clear_bit(R5_OVERWRITE, &dev->flags);
1985                                         }
1986                                 }
1987                                 wbi = r5_next_bio(conf, wbi, dev->sector);
1988                         }
1989
1990                         if (head_sh->batch_head) {
1991                                 sh = list_first_entry(&sh->batch_list,
1992                                                       struct stripe_head,
1993                                                       batch_list);
1994                                 if (sh == head_sh)
1995                                         continue;
1996                                 goto again;
1997                         }
1998                 }
1999         }
2000
2001         return tx;
2002 }
2003
2004 static void ops_complete_reconstruct(void *stripe_head_ref)
2005 {
2006         struct stripe_head *sh = stripe_head_ref;
2007         int disks = sh->disks;
2008         int pd_idx = sh->pd_idx;
2009         int qd_idx = sh->qd_idx;
2010         int i;
2011         bool fua = false, sync = false, discard = false;
2012
2013         pr_debug("%s: stripe %llu\n", __func__,
2014                 (unsigned long long)sh->sector);
2015
2016         for (i = disks; i--; ) {
2017                 fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
2018                 sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
2019                 discard |= test_bit(R5_Discard, &sh->dev[i].flags);
2020         }
2021
2022         for (i = disks; i--; ) {
2023                 struct r5dev *dev = &sh->dev[i];
2024
2025                 if (dev->written || i == pd_idx || i == qd_idx) {
2026                         if (!discard && !test_bit(R5_SkipCopy, &dev->flags)) {
2027                                 set_bit(R5_UPTODATE, &dev->flags);
2028                                 if (test_bit(STRIPE_EXPAND_READY, &sh->state))
2029                                         set_bit(R5_Expanded, &dev->flags);
2030                         }
2031                         if (fua)
2032                                 set_bit(R5_WantFUA, &dev->flags);
2033                         if (sync)
2034                                 set_bit(R5_SyncIO, &dev->flags);
2035                 }
2036         }
2037
2038         if (sh->reconstruct_state == reconstruct_state_drain_run)
2039                 sh->reconstruct_state = reconstruct_state_drain_result;
2040         else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
2041                 sh->reconstruct_state = reconstruct_state_prexor_drain_result;
2042         else {
2043                 BUG_ON(sh->reconstruct_state != reconstruct_state_run);
2044                 sh->reconstruct_state = reconstruct_state_result;
2045         }
2046
2047         set_bit(STRIPE_HANDLE, &sh->state);
2048         raid5_release_stripe(sh);
2049 }
2050
2051 static void
2052 ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
2053                      struct dma_async_tx_descriptor *tx)
2054 {
2055         int disks = sh->disks;
2056         struct page **xor_srcs;
2057         unsigned int *off_srcs;
2058         struct async_submit_ctl submit;
2059         int count, pd_idx = sh->pd_idx, i;
2060         struct page *xor_dest;
2061         unsigned int off_dest;
2062         int prexor = 0;
2063         unsigned long flags;
2064         int j = 0;
2065         struct stripe_head *head_sh = sh;
2066         int last_stripe;
2067
2068         pr_debug("%s: stripe %llu\n", __func__,
2069                 (unsigned long long)sh->sector);
2070
2071         for (i = 0; i < sh->disks; i++) {
2072                 if (pd_idx == i)
2073                         continue;
2074                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
2075                         break;
2076         }
2077         if (i >= sh->disks) {
2078                 atomic_inc(&sh->count);
2079                 set_bit(R5_Discard, &sh->dev[pd_idx].flags);
2080                 ops_complete_reconstruct(sh);
2081                 return;
2082         }
2083 again:
2084         count = 0;
2085         xor_srcs = to_addr_page(percpu, j);
2086         off_srcs = to_addr_offs(sh, percpu);
2087         /* check if prexor is active which means only process blocks
2088          * that are part of a read-modify-write (written)
2089          */
2090         if (head_sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
2091                 prexor = 1;
2092                 off_dest = off_srcs[count] = sh->dev[pd_idx].offset;
2093                 xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
2094                 for (i = disks; i--; ) {
2095                         struct r5dev *dev = &sh->dev[i];
2096                         if (head_sh->dev[i].written ||
2097                             test_bit(R5_InJournal, &head_sh->dev[i].flags)) {
2098                                 off_srcs[count] = dev->offset;
2099                                 xor_srcs[count++] = dev->page;
2100                         }
2101                 }
2102         } else {
2103                 xor_dest = sh->dev[pd_idx].page;
2104                 off_dest = sh->dev[pd_idx].offset;
2105                 for (i = disks; i--; ) {
2106                         struct r5dev *dev = &sh->dev[i];
2107                         if (i != pd_idx) {
2108                                 off_srcs[count] = dev->offset;
2109                                 xor_srcs[count++] = dev->page;
2110                         }
2111                 }
2112         }
2113
2114         /* 1/ if we prexor'd then the dest is reused as a source
2115          * 2/ if we did not prexor then we are redoing the parity
2116          * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
2117          * for the synchronous xor case
2118          */
2119         last_stripe = !head_sh->batch_head ||
2120                 list_first_entry(&sh->batch_list,
2121                                  struct stripe_head, batch_list) == head_sh;
2122         if (last_stripe) {
2123                 flags = ASYNC_TX_ACK |
2124                         (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
2125
2126                 atomic_inc(&head_sh->count);
2127                 init_async_submit(&submit, flags, tx, ops_complete_reconstruct, head_sh,
2128                                   to_addr_conv(sh, percpu, j));
2129         } else {
2130                 flags = prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST;
2131                 init_async_submit(&submit, flags, tx, NULL, NULL,
2132                                   to_addr_conv(sh, percpu, j));
2133         }
2134
2135         if (unlikely(count == 1))
2136                 tx = async_memcpy(xor_dest, xor_srcs[0], off_dest, off_srcs[0],
2137                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
2138         else
2139                 tx = async_xor_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
2140                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
2141         if (!last_stripe) {
2142                 j++;
2143                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
2144                                       batch_list);
2145                 goto again;
2146         }
2147 }
2148
2149 static void
2150 ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
2151                      struct dma_async_tx_descriptor *tx)
2152 {
2153         struct async_submit_ctl submit;
2154         struct page **blocks;
2155         unsigned int *offs;
2156         int count, i, j = 0;
2157         struct stripe_head *head_sh = sh;
2158         int last_stripe;
2159         int synflags;
2160         unsigned long txflags;
2161
2162         pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
2163
2164         for (i = 0; i < sh->disks; i++) {
2165                 if (sh->pd_idx == i || sh->qd_idx == i)
2166                         continue;
2167                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
2168                         break;
2169         }
2170         if (i >= sh->disks) {
2171                 atomic_inc(&sh->count);
2172                 set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
2173                 set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
2174                 ops_complete_reconstruct(sh);
2175                 return;
2176         }
2177
2178 again:
2179         blocks = to_addr_page(percpu, j);
2180         offs = to_addr_offs(sh, percpu);
2181
2182         if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
2183                 synflags = SYNDROME_SRC_WRITTEN;
2184                 txflags = ASYNC_TX_ACK | ASYNC_TX_PQ_XOR_DST;
2185         } else {
2186                 synflags = SYNDROME_SRC_ALL;
2187                 txflags = ASYNC_TX_ACK;
2188         }
2189
2190         count = set_syndrome_sources(blocks, offs, sh, synflags);
2191         last_stripe = !head_sh->batch_head ||
2192                 list_first_entry(&sh->batch_list,
2193                                  struct stripe_head, batch_list) == head_sh;
2194
2195         if (last_stripe) {
2196                 atomic_inc(&head_sh->count);
2197                 init_async_submit(&submit, txflags, tx, ops_complete_reconstruct,
2198                                   head_sh, to_addr_conv(sh, percpu, j));
2199         } else
2200                 init_async_submit(&submit, 0, tx, NULL, NULL,
2201                                   to_addr_conv(sh, percpu, j));
2202         tx = async_gen_syndrome(blocks, offs, count+2,
2203                         RAID5_STRIPE_SIZE(sh->raid_conf),  &submit);
2204         if (!last_stripe) {
2205                 j++;
2206                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
2207                                       batch_list);
2208                 goto again;
2209         }
2210 }
2211
2212 static void ops_complete_check(void *stripe_head_ref)
2213 {
2214         struct stripe_head *sh = stripe_head_ref;
2215
2216         pr_debug("%s: stripe %llu\n", __func__,
2217                 (unsigned long long)sh->sector);
2218
2219         sh->check_state = check_state_check_result;
2220         set_bit(STRIPE_HANDLE, &sh->state);
2221         raid5_release_stripe(sh);
2222 }
2223
2224 static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
2225 {
2226         int disks = sh->disks;
2227         int pd_idx = sh->pd_idx;
2228         int qd_idx = sh->qd_idx;
2229         struct page *xor_dest;
2230         unsigned int off_dest;
2231         struct page **xor_srcs = to_addr_page(percpu, 0);
2232         unsigned int *off_srcs = to_addr_offs(sh, percpu);
2233         struct dma_async_tx_descriptor *tx;
2234         struct async_submit_ctl submit;
2235         int count;
2236         int i;
2237
2238         pr_debug("%s: stripe %llu\n", __func__,
2239                 (unsigned long long)sh->sector);
2240
2241         BUG_ON(sh->batch_head);
2242         count = 0;
2243         xor_dest = sh->dev[pd_idx].page;
2244         off_dest = sh->dev[pd_idx].offset;
2245         off_srcs[count] = off_dest;
2246         xor_srcs[count++] = xor_dest;
2247         for (i = disks; i--; ) {
2248                 if (i == pd_idx || i == qd_idx)
2249                         continue;
2250                 off_srcs[count] = sh->dev[i].offset;
2251                 xor_srcs[count++] = sh->dev[i].page;
2252         }
2253
2254         init_async_submit(&submit, 0, NULL, NULL, NULL,
2255                           to_addr_conv(sh, percpu, 0));
2256         tx = async_xor_val_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
2257                            RAID5_STRIPE_SIZE(sh->raid_conf),
2258                            &sh->ops.zero_sum_result, &submit);
2259
2260         atomic_inc(&sh->count);
2261         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
2262         tx = async_trigger_callback(&submit);
2263 }
2264
2265 static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
2266 {
2267         struct page **srcs = to_addr_page(percpu, 0);
2268         unsigned int *offs = to_addr_offs(sh, percpu);
2269         struct async_submit_ctl submit;
2270         int count;
2271
2272         pr_debug("%s: stripe %llu checkp: %d\n", __func__,
2273                 (unsigned long long)sh->sector, checkp);
2274
2275         BUG_ON(sh->batch_head);
2276         count = set_syndrome_sources(srcs, offs, sh, SYNDROME_SRC_ALL);
2277         if (!checkp)
2278                 srcs[count] = NULL;
2279
2280         atomic_inc(&sh->count);
2281         init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
2282                           sh, to_addr_conv(sh, percpu, 0));
2283         async_syndrome_val(srcs, offs, count+2,
2284                            RAID5_STRIPE_SIZE(sh->raid_conf),
2285                            &sh->ops.zero_sum_result, percpu->spare_page, 0, &submit);
2286 }
2287
2288 static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
2289 {
2290         int overlap_clear = 0, i, disks = sh->disks;
2291         struct dma_async_tx_descriptor *tx = NULL;
2292         struct r5conf *conf = sh->raid_conf;
2293         int level = conf->level;
2294         struct raid5_percpu *percpu;
2295
2296         local_lock(&conf->percpu->lock);
2297         percpu = this_cpu_ptr(conf->percpu);
2298         if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
2299                 ops_run_biofill(sh);
2300                 overlap_clear++;
2301         }
2302
2303         if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
2304                 if (level < 6)
2305                         tx = ops_run_compute5(sh, percpu);
2306                 else {
2307                         if (sh->ops.target2 < 0 || sh->ops.target < 0)
2308                                 tx = ops_run_compute6_1(sh, percpu);
2309                         else
2310                                 tx = ops_run_compute6_2(sh, percpu);
2311                 }
2312                 /* terminate the chain if reconstruct is not set to be run */
2313                 if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
2314                         async_tx_ack(tx);
2315         }
2316
2317         if (test_bit(STRIPE_OP_PREXOR, &ops_request)) {
2318                 if (level < 6)
2319                         tx = ops_run_prexor5(sh, percpu, tx);
2320                 else
2321                         tx = ops_run_prexor6(sh, percpu, tx);
2322         }
2323
2324         if (test_bit(STRIPE_OP_PARTIAL_PARITY, &ops_request))
2325                 tx = ops_run_partial_parity(sh, percpu, tx);
2326
2327         if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
2328                 tx = ops_run_biodrain(sh, tx);
2329                 overlap_clear++;
2330         }
2331
2332         if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
2333                 if (level < 6)
2334                         ops_run_reconstruct5(sh, percpu, tx);
2335                 else
2336                         ops_run_reconstruct6(sh, percpu, tx);
2337         }
2338
2339         if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
2340                 if (sh->check_state == check_state_run)
2341                         ops_run_check_p(sh, percpu);
2342                 else if (sh->check_state == check_state_run_q)
2343                         ops_run_check_pq(sh, percpu, 0);
2344                 else if (sh->check_state == check_state_run_pq)
2345                         ops_run_check_pq(sh, percpu, 1);
2346                 else
2347                         BUG();
2348         }
2349
2350         if (overlap_clear && !sh->batch_head) {
2351                 for (i = disks; i--; ) {
2352                         struct r5dev *dev = &sh->dev[i];
2353                         if (test_and_clear_bit(R5_Overlap, &dev->flags))
2354                                 wake_up(&sh->raid_conf->wait_for_overlap);
2355                 }
2356         }
2357         local_unlock(&conf->percpu->lock);
2358 }
2359
2360 static void free_stripe(struct kmem_cache *sc, struct stripe_head *sh)
2361 {
2362 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2363         kfree(sh->pages);
2364 #endif
2365         if (sh->ppl_page)
2366                 __free_page(sh->ppl_page);
2367         kmem_cache_free(sc, sh);
2368 }
2369
2370 static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp,
2371         int disks, struct r5conf *conf)
2372 {
2373         struct stripe_head *sh;
2374
2375         sh = kmem_cache_zalloc(sc, gfp);
2376         if (sh) {
2377                 spin_lock_init(&sh->stripe_lock);
2378                 spin_lock_init(&sh->batch_lock);
2379                 INIT_LIST_HEAD(&sh->batch_list);
2380                 INIT_LIST_HEAD(&sh->lru);
2381                 INIT_LIST_HEAD(&sh->r5c);
2382                 INIT_LIST_HEAD(&sh->log_list);
2383                 atomic_set(&sh->count, 1);
2384                 sh->raid_conf = conf;
2385                 sh->log_start = MaxSector;
2386
2387                 if (raid5_has_ppl(conf)) {
2388                         sh->ppl_page = alloc_page(gfp);
2389                         if (!sh->ppl_page) {
2390                                 free_stripe(sc, sh);
2391                                 return NULL;
2392                         }
2393                 }
2394 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2395                 if (init_stripe_shared_pages(sh, conf, disks)) {
2396                         free_stripe(sc, sh);
2397                         return NULL;
2398                 }
2399 #endif
2400         }
2401         return sh;
2402 }
2403 static int grow_one_stripe(struct r5conf *conf, gfp_t gfp)
2404 {
2405         struct stripe_head *sh;
2406
2407         sh = alloc_stripe(conf->slab_cache, gfp, conf->pool_size, conf);
2408         if (!sh)
2409                 return 0;
2410
2411         if (grow_buffers(sh, gfp)) {
2412                 shrink_buffers(sh);
2413                 free_stripe(conf->slab_cache, sh);
2414                 return 0;
2415         }
2416         sh->hash_lock_index =
2417                 conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS;
2418         /* we just created an active stripe so... */
2419         atomic_inc(&conf->active_stripes);
2420
2421         raid5_release_stripe(sh);
2422         conf->max_nr_stripes++;
2423         return 1;
2424 }
2425
2426 static int grow_stripes(struct r5conf *conf, int num)
2427 {
2428         struct kmem_cache *sc;
2429         size_t namelen = sizeof(conf->cache_name[0]);
2430         int devs = max(conf->raid_disks, conf->previous_raid_disks);
2431
2432         if (conf->mddev->gendisk)
2433                 snprintf(conf->cache_name[0], namelen,
2434                         "raid%d-%s", conf->level, mdname(conf->mddev));
2435         else
2436                 snprintf(conf->cache_name[0], namelen,
2437                         "raid%d-%p", conf->level, conf->mddev);
2438         snprintf(conf->cache_name[1], namelen, "%.27s-alt", conf->cache_name[0]);
2439
2440         conf->active_name = 0;
2441         sc = kmem_cache_create(conf->cache_name[conf->active_name],
2442                                sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
2443                                0, 0, NULL);
2444         if (!sc)
2445                 return 1;
2446         conf->slab_cache = sc;
2447         conf->pool_size = devs;
2448         while (num--)
2449                 if (!grow_one_stripe(conf, GFP_KERNEL))
2450                         return 1;
2451
2452         return 0;
2453 }
2454
2455 /**
2456  * scribble_alloc - allocate percpu scribble buffer for required size
2457  *                  of the scribble region
2458  * @percpu: from for_each_present_cpu() of the caller
2459  * @num: total number of disks in the array
2460  * @cnt: scribble objs count for required size of the scribble region
2461  *
2462  * The scribble buffer size must be enough to contain:
2463  * 1/ a struct page pointer for each device in the array +2
2464  * 2/ room to convert each entry in (1) to its corresponding dma
2465  *    (dma_map_page()) or page (page_address()) address.
2466  *
2467  * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
2468  * calculate over all devices (not just the data blocks), using zeros in place
2469  * of the P and Q blocks.
2470  */
2471 static int scribble_alloc(struct raid5_percpu *percpu,
2472                           int num, int cnt)
2473 {
2474         size_t obj_size =
2475                 sizeof(struct page *) * (num + 2) +
2476                 sizeof(addr_conv_t) * (num + 2) +
2477                 sizeof(unsigned int) * (num + 2);
2478         void *scribble;
2479
2480         /*
2481          * If here is in raid array suspend context, it is in memalloc noio
2482          * context as well, there is no potential recursive memory reclaim
2483          * I/Os with the GFP_KERNEL flag.
2484          */
2485         scribble = kvmalloc_array(cnt, obj_size, GFP_KERNEL);
2486         if (!scribble)
2487                 return -ENOMEM;
2488
2489         kvfree(percpu->scribble);
2490
2491         percpu->scribble = scribble;
2492         percpu->scribble_obj_size = obj_size;
2493         return 0;
2494 }
2495
2496 static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
2497 {
2498         unsigned long cpu;
2499         int err = 0;
2500
2501         /*
2502          * Never shrink. And mddev_suspend() could deadlock if this is called
2503          * from raid5d. In that case, scribble_disks and scribble_sectors
2504          * should equal to new_disks and new_sectors
2505          */
2506         if (conf->scribble_disks >= new_disks &&
2507             conf->scribble_sectors >= new_sectors)
2508                 return 0;
2509         mddev_suspend(conf->mddev);
2510         cpus_read_lock();
2511
2512         for_each_present_cpu(cpu) {
2513                 struct raid5_percpu *percpu;
2514
2515                 percpu = per_cpu_ptr(conf->percpu, cpu);
2516                 err = scribble_alloc(percpu, new_disks,
2517                                      new_sectors / RAID5_STRIPE_SECTORS(conf));
2518                 if (err)
2519                         break;
2520         }
2521
2522         cpus_read_unlock();
2523         mddev_resume(conf->mddev);
2524         if (!err) {
2525                 conf->scribble_disks = new_disks;
2526                 conf->scribble_sectors = new_sectors;
2527         }
2528         return err;
2529 }
2530
2531 static int resize_stripes(struct r5conf *conf, int newsize)
2532 {
2533         /* Make all the stripes able to hold 'newsize' devices.
2534          * New slots in each stripe get 'page' set to a new page.
2535          *
2536          * This happens in stages:
2537          * 1/ create a new kmem_cache and allocate the required number of
2538          *    stripe_heads.
2539          * 2/ gather all the old stripe_heads and transfer the pages across
2540          *    to the new stripe_heads.  This will have the side effect of
2541          *    freezing the array as once all stripe_heads have been collected,
2542          *    no IO will be possible.  Old stripe heads are freed once their
2543          *    pages have been transferred over, and the old kmem_cache is
2544          *    freed when all stripes are done.
2545          * 3/ reallocate conf->disks to be suitable bigger.  If this fails,
2546          *    we simple return a failure status - no need to clean anything up.
2547          * 4/ allocate new pages for the new slots in the new stripe_heads.
2548          *    If this fails, we don't bother trying the shrink the
2549          *    stripe_heads down again, we just leave them as they are.
2550          *    As each stripe_head is processed the new one is released into
2551          *    active service.
2552          *
2553          * Once step2 is started, we cannot afford to wait for a write,
2554          * so we use GFP_NOIO allocations.
2555          */
2556         struct stripe_head *osh, *nsh;
2557         LIST_HEAD(newstripes);
2558         struct disk_info *ndisks;
2559         int err = 0;
2560         struct kmem_cache *sc;
2561         int i;
2562         int hash, cnt;
2563
2564         md_allow_write(conf->mddev);
2565
2566         /* Step 1 */
2567         sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
2568                                sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
2569                                0, 0, NULL);
2570         if (!sc)
2571                 return -ENOMEM;
2572
2573         /* Need to ensure auto-resizing doesn't interfere */
2574         mutex_lock(&conf->cache_size_mutex);
2575
2576         for (i = conf->max_nr_stripes; i; i--) {
2577                 nsh = alloc_stripe(sc, GFP_KERNEL, newsize, conf);
2578                 if (!nsh)
2579                         break;
2580
2581                 list_add(&nsh->lru, &newstripes);
2582         }
2583         if (i) {
2584                 /* didn't get enough, give up */
2585                 while (!list_empty(&newstripes)) {
2586                         nsh = list_entry(newstripes.next, struct stripe_head, lru);
2587                         list_del(&nsh->lru);
2588                         free_stripe(sc, nsh);
2589                 }
2590                 kmem_cache_destroy(sc);
2591                 mutex_unlock(&conf->cache_size_mutex);
2592                 return -ENOMEM;
2593         }
2594         /* Step 2 - Must use GFP_NOIO now.
2595          * OK, we have enough stripes, start collecting inactive
2596          * stripes and copying them over
2597          */
2598         hash = 0;
2599         cnt = 0;
2600         list_for_each_entry(nsh, &newstripes, lru) {
2601                 lock_device_hash_lock(conf, hash);
2602                 wait_event_cmd(conf->wait_for_stripe,
2603                                     !list_empty(conf->inactive_list + hash),
2604                                     unlock_device_hash_lock(conf, hash),
2605                                     lock_device_hash_lock(conf, hash));
2606                 osh = get_free_stripe(conf, hash);
2607                 unlock_device_hash_lock(conf, hash);
2608
2609 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2610         for (i = 0; i < osh->nr_pages; i++) {
2611                 nsh->pages[i] = osh->pages[i];
2612                 osh->pages[i] = NULL;
2613         }
2614 #endif
2615                 for(i=0; i<conf->pool_size; i++) {
2616                         nsh->dev[i].page = osh->dev[i].page;
2617                         nsh->dev[i].orig_page = osh->dev[i].page;
2618                         nsh->dev[i].offset = osh->dev[i].offset;
2619                 }
2620                 nsh->hash_lock_index = hash;
2621                 free_stripe(conf->slab_cache, osh);
2622                 cnt++;
2623                 if (cnt >= conf->max_nr_stripes / NR_STRIPE_HASH_LOCKS +
2624                     !!((conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS) > hash)) {
2625                         hash++;
2626                         cnt = 0;
2627                 }
2628         }
2629         kmem_cache_destroy(conf->slab_cache);
2630
2631         /* Step 3.
2632          * At this point, we are holding all the stripes so the array
2633          * is completely stalled, so now is a good time to resize
2634          * conf->disks and the scribble region
2635          */
2636         ndisks = kcalloc(newsize, sizeof(struct disk_info), GFP_NOIO);
2637         if (ndisks) {
2638                 for (i = 0; i < conf->pool_size; i++)
2639                         ndisks[i] = conf->disks[i];
2640
2641                 for (i = conf->pool_size; i < newsize; i++) {
2642                         ndisks[i].extra_page = alloc_page(GFP_NOIO);
2643                         if (!ndisks[i].extra_page)
2644                                 err = -ENOMEM;
2645                 }
2646
2647                 if (err) {
2648                         for (i = conf->pool_size; i < newsize; i++)
2649                                 if (ndisks[i].extra_page)
2650                                         put_page(ndisks[i].extra_page);
2651                         kfree(ndisks);
2652                 } else {
2653                         kfree(conf->disks);
2654                         conf->disks = ndisks;
2655                 }
2656         } else
2657                 err = -ENOMEM;
2658
2659         conf->slab_cache = sc;
2660         conf->active_name = 1-conf->active_name;
2661
2662         /* Step 4, return new stripes to service */
2663         while(!list_empty(&newstripes)) {
2664                 nsh = list_entry(newstripes.next, struct stripe_head, lru);
2665                 list_del_init(&nsh->lru);
2666
2667 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2668                 for (i = 0; i < nsh->nr_pages; i++) {
2669                         if (nsh->pages[i])
2670                                 continue;
2671                         nsh->pages[i] = alloc_page(GFP_NOIO);
2672                         if (!nsh->pages[i])
2673                                 err = -ENOMEM;
2674                 }
2675
2676                 for (i = conf->raid_disks; i < newsize; i++) {
2677                         if (nsh->dev[i].page)
2678                                 continue;
2679                         nsh->dev[i].page = raid5_get_dev_page(nsh, i);
2680                         nsh->dev[i].orig_page = nsh->dev[i].page;
2681                         nsh->dev[i].offset = raid5_get_page_offset(nsh, i);
2682                 }
2683 #else
2684                 for (i=conf->raid_disks; i < newsize; i++)
2685                         if (nsh->dev[i].page == NULL) {
2686                                 struct page *p = alloc_page(GFP_NOIO);
2687                                 nsh->dev[i].page = p;
2688                                 nsh->dev[i].orig_page = p;
2689                                 nsh->dev[i].offset = 0;
2690                                 if (!p)
2691                                         err = -ENOMEM;
2692                         }
2693 #endif
2694                 raid5_release_stripe(nsh);
2695         }
2696         /* critical section pass, GFP_NOIO no longer needed */
2697
2698         if (!err)
2699                 conf->pool_size = newsize;
2700         mutex_unlock(&conf->cache_size_mutex);
2701
2702         return err;
2703 }
2704
2705 static int drop_one_stripe(struct r5conf *conf)
2706 {
2707         struct stripe_head *sh;
2708         int hash = (conf->max_nr_stripes - 1) & STRIPE_HASH_LOCKS_MASK;
2709
2710         spin_lock_irq(conf->hash_locks + hash);
2711         sh = get_free_stripe(conf, hash);
2712         spin_unlock_irq(conf->hash_locks + hash);
2713         if (!sh)
2714                 return 0;
2715         BUG_ON(atomic_read(&sh->count));
2716         shrink_buffers(sh);
2717         free_stripe(conf->slab_cache, sh);
2718         atomic_dec(&conf->active_stripes);
2719         conf->max_nr_stripes--;
2720         return 1;
2721 }
2722
2723 static void shrink_stripes(struct r5conf *conf)
2724 {
2725         while (conf->max_nr_stripes &&
2726                drop_one_stripe(conf))
2727                 ;
2728
2729         kmem_cache_destroy(conf->slab_cache);
2730         conf->slab_cache = NULL;
2731 }
2732
2733 /*
2734  * This helper wraps rcu_dereference_protected() and can be used when
2735  * it is known that the nr_pending of the rdev is elevated.
2736  */
2737 static struct md_rdev *rdev_pend_deref(struct md_rdev __rcu *rdev)
2738 {
2739         return rcu_dereference_protected(rdev,
2740                         atomic_read(&rcu_access_pointer(rdev)->nr_pending));
2741 }
2742
2743 /*
2744  * This helper wraps rcu_dereference_protected() and should be used
2745  * when it is known that the mddev_lock() is held. This is safe
2746  * seeing raid5_remove_disk() has the same lock held.
2747  */
2748 static struct md_rdev *rdev_mdlock_deref(struct mddev *mddev,
2749                                          struct md_rdev __rcu *rdev)
2750 {
2751         return rcu_dereference_protected(rdev,
2752                         lockdep_is_held(&mddev->reconfig_mutex));
2753 }
2754
2755 static void raid5_end_read_request(struct bio * bi)
2756 {
2757         struct stripe_head *sh = bi->bi_private;
2758         struct r5conf *conf = sh->raid_conf;
2759         int disks = sh->disks, i;
2760         struct md_rdev *rdev = NULL;
2761         sector_t s;
2762
2763         for (i=0 ; i<disks; i++)
2764                 if (bi == &sh->dev[i].req)
2765                         break;
2766
2767         pr_debug("end_read_request %llu/%d, count: %d, error %d.\n",
2768                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2769                 bi->bi_status);
2770         if (i == disks) {
2771                 BUG();
2772                 return;
2773         }
2774         if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2775                 /* If replacement finished while this request was outstanding,
2776                  * 'replacement' might be NULL already.
2777                  * In that case it moved down to 'rdev'.
2778                  * rdev is not removed until all requests are finished.
2779                  */
2780                 rdev = rdev_pend_deref(conf->disks[i].replacement);
2781         if (!rdev)
2782                 rdev = rdev_pend_deref(conf->disks[i].rdev);
2783
2784         if (use_new_offset(conf, sh))
2785                 s = sh->sector + rdev->new_data_offset;
2786         else
2787                 s = sh->sector + rdev->data_offset;
2788         if (!bi->bi_status) {
2789                 set_bit(R5_UPTODATE, &sh->dev[i].flags);
2790                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2791                         /* Note that this cannot happen on a
2792                          * replacement device.  We just fail those on
2793                          * any error
2794                          */
2795                         pr_info_ratelimited(
2796                                 "md/raid:%s: read error corrected (%lu sectors at %llu on %pg)\n",
2797                                 mdname(conf->mddev), RAID5_STRIPE_SECTORS(conf),
2798                                 (unsigned long long)s,
2799                                 rdev->bdev);
2800                         atomic_add(RAID5_STRIPE_SECTORS(conf), &rdev->corrected_errors);
2801                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2802                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2803                 } else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2804                         clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2805
2806                 if (test_bit(R5_InJournal, &sh->dev[i].flags))
2807                         /*
2808                          * end read for a page in journal, this
2809                          * must be preparing for prexor in rmw
2810                          */
2811                         set_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags);
2812
2813                 if (atomic_read(&rdev->read_errors))
2814                         atomic_set(&rdev->read_errors, 0);
2815         } else {
2816                 int retry = 0;
2817                 int set_bad = 0;
2818
2819                 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
2820                 if (!(bi->bi_status == BLK_STS_PROTECTION))
2821                         atomic_inc(&rdev->read_errors);
2822                 if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2823                         pr_warn_ratelimited(
2824                                 "md/raid:%s: read error on replacement device (sector %llu on %pg).\n",
2825                                 mdname(conf->mddev),
2826                                 (unsigned long long)s,
2827                                 rdev->bdev);
2828                 else if (conf->mddev->degraded >= conf->max_degraded) {
2829                         set_bad = 1;
2830                         pr_warn_ratelimited(
2831                                 "md/raid:%s: read error not correctable (sector %llu on %pg).\n",
2832                                 mdname(conf->mddev),
2833                                 (unsigned long long)s,
2834                                 rdev->bdev);
2835                 } else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
2836                         /* Oh, no!!! */
2837                         set_bad = 1;
2838                         pr_warn_ratelimited(
2839                                 "md/raid:%s: read error NOT corrected!! (sector %llu on %pg).\n",
2840                                 mdname(conf->mddev),
2841                                 (unsigned long long)s,
2842                                 rdev->bdev);
2843                 } else if (atomic_read(&rdev->read_errors)
2844                          > conf->max_nr_stripes) {
2845                         if (!test_bit(Faulty, &rdev->flags)) {
2846                                 pr_warn("md/raid:%s: %d read_errors > %d stripes\n",
2847                                     mdname(conf->mddev),
2848                                     atomic_read(&rdev->read_errors),
2849                                     conf->max_nr_stripes);
2850                                 pr_warn("md/raid:%s: Too many read errors, failing device %pg.\n",
2851                                     mdname(conf->mddev), rdev->bdev);
2852                         }
2853                 } else
2854                         retry = 1;
2855                 if (set_bad && test_bit(In_sync, &rdev->flags)
2856                     && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2857                         retry = 1;
2858                 if (retry)
2859                         if (sh->qd_idx >= 0 && sh->pd_idx == i)
2860                                 set_bit(R5_ReadError, &sh->dev[i].flags);
2861                         else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
2862                                 set_bit(R5_ReadError, &sh->dev[i].flags);
2863                                 clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2864                         } else
2865                                 set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2866                 else {
2867                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2868                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2869                         if (!(set_bad
2870                               && test_bit(In_sync, &rdev->flags)
2871                               && rdev_set_badblocks(
2872                                       rdev, sh->sector, RAID5_STRIPE_SECTORS(conf), 0)))
2873                                 md_error(conf->mddev, rdev);
2874                 }
2875         }
2876         rdev_dec_pending(rdev, conf->mddev);
2877         bio_uninit(bi);
2878         clear_bit(R5_LOCKED, &sh->dev[i].flags);
2879         set_bit(STRIPE_HANDLE, &sh->state);
2880         raid5_release_stripe(sh);
2881 }
2882
2883 static void raid5_end_write_request(struct bio *bi)
2884 {
2885         struct stripe_head *sh = bi->bi_private;
2886         struct r5conf *conf = sh->raid_conf;
2887         int disks = sh->disks, i;
2888         struct md_rdev *rdev;
2889         sector_t first_bad;
2890         int bad_sectors;
2891         int replacement = 0;
2892
2893         for (i = 0 ; i < disks; i++) {
2894                 if (bi == &sh->dev[i].req) {
2895                         rdev = rdev_pend_deref(conf->disks[i].rdev);
2896                         break;
2897                 }
2898                 if (bi == &sh->dev[i].rreq) {
2899                         rdev = rdev_pend_deref(conf->disks[i].replacement);
2900                         if (rdev)
2901                                 replacement = 1;
2902                         else
2903                                 /* rdev was removed and 'replacement'
2904                                  * replaced it.  rdev is not removed
2905                                  * until all requests are finished.
2906                                  */
2907                                 rdev = rdev_pend_deref(conf->disks[i].rdev);
2908                         break;
2909                 }
2910         }
2911         pr_debug("end_write_request %llu/%d, count %d, error: %d.\n",
2912                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2913                 bi->bi_status);
2914         if (i == disks) {
2915                 BUG();
2916                 return;
2917         }
2918
2919         if (replacement) {
2920                 if (bi->bi_status)
2921                         md_error(conf->mddev, rdev);
2922                 else if (is_badblock(rdev, sh->sector,
2923                                      RAID5_STRIPE_SECTORS(conf),
2924                                      &first_bad, &bad_sectors))
2925                         set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
2926         } else {
2927                 if (bi->bi_status) {
2928                         set_bit(STRIPE_DEGRADED, &sh->state);
2929                         set_bit(WriteErrorSeen, &rdev->flags);
2930                         set_bit(R5_WriteError, &sh->dev[i].flags);
2931                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
2932                                 set_bit(MD_RECOVERY_NEEDED,
2933                                         &rdev->mddev->recovery);
2934                 } else if (is_badblock(rdev, sh->sector,
2935                                        RAID5_STRIPE_SECTORS(conf),
2936                                        &first_bad, &bad_sectors)) {
2937                         set_bit(R5_MadeGood, &sh->dev[i].flags);
2938                         if (test_bit(R5_ReadError, &sh->dev[i].flags))
2939                                 /* That was a successful write so make
2940                                  * sure it looks like we already did
2941                                  * a re-write.
2942                                  */
2943                                 set_bit(R5_ReWrite, &sh->dev[i].flags);
2944                 }
2945         }
2946         rdev_dec_pending(rdev, conf->mddev);
2947
2948         if (sh->batch_head && bi->bi_status && !replacement)
2949                 set_bit(STRIPE_BATCH_ERR, &sh->batch_head->state);
2950
2951         bio_uninit(bi);
2952         if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
2953                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
2954         set_bit(STRIPE_HANDLE, &sh->state);
2955
2956         if (sh->batch_head && sh != sh->batch_head)
2957                 raid5_release_stripe(sh->batch_head);
2958         raid5_release_stripe(sh);
2959 }
2960
2961 static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
2962 {
2963         struct r5conf *conf = mddev->private;
2964         unsigned long flags;
2965         pr_debug("raid456: error called\n");
2966
2967         pr_crit("md/raid:%s: Disk failure on %pg, disabling device.\n",
2968                 mdname(mddev), rdev->bdev);
2969
2970         spin_lock_irqsave(&conf->device_lock, flags);
2971         set_bit(Faulty, &rdev->flags);
2972         clear_bit(In_sync, &rdev->flags);
2973         mddev->degraded = raid5_calc_degraded(conf);
2974
2975         if (has_failed(conf)) {
2976                 set_bit(MD_BROKEN, &conf->mddev->flags);
2977                 conf->recovery_disabled = mddev->recovery_disabled;
2978
2979                 pr_crit("md/raid:%s: Cannot continue operation (%d/%d failed).\n",
2980                         mdname(mddev), mddev->degraded, conf->raid_disks);
2981         } else {
2982                 pr_crit("md/raid:%s: Operation continuing on %d devices.\n",
2983                         mdname(mddev), conf->raid_disks - mddev->degraded);
2984         }
2985
2986         spin_unlock_irqrestore(&conf->device_lock, flags);
2987         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2988
2989         set_bit(Blocked, &rdev->flags);
2990         set_mask_bits(&mddev->sb_flags, 0,
2991                       BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
2992         r5c_update_on_rdev_error(mddev, rdev);
2993 }
2994
2995 /*
2996  * Input: a 'big' sector number,
2997  * Output: index of the data and parity disk, and the sector # in them.
2998  */
2999 sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
3000                               int previous, int *dd_idx,
3001                               struct stripe_head *sh)
3002 {
3003         sector_t stripe, stripe2;
3004         sector_t chunk_number;
3005         unsigned int chunk_offset;
3006         int pd_idx, qd_idx;
3007         int ddf_layout = 0;
3008         sector_t new_sector;
3009         int algorithm = previous ? conf->prev_algo
3010                                  : conf->algorithm;
3011         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
3012                                          : conf->chunk_sectors;
3013         int raid_disks = previous ? conf->previous_raid_disks
3014                                   : conf->raid_disks;
3015         int data_disks = raid_disks - conf->max_degraded;
3016
3017         /* First compute the information on this sector */
3018
3019         /*
3020          * Compute the chunk number and the sector offset inside the chunk
3021          */
3022         chunk_offset = sector_div(r_sector, sectors_per_chunk);
3023         chunk_number = r_sector;
3024
3025         /*
3026          * Compute the stripe number
3027          */
3028         stripe = chunk_number;
3029         *dd_idx = sector_div(stripe, data_disks);
3030         stripe2 = stripe;
3031         /*
3032          * Select the parity disk based on the user selected algorithm.
3033          */
3034         pd_idx = qd_idx = -1;
3035         switch(conf->level) {
3036         case 4:
3037                 pd_idx = data_disks;
3038                 break;
3039         case 5:
3040                 switch (algorithm) {
3041                 case ALGORITHM_LEFT_ASYMMETRIC:
3042                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
3043                         if (*dd_idx >= pd_idx)
3044                                 (*dd_idx)++;
3045                         break;
3046                 case ALGORITHM_RIGHT_ASYMMETRIC:
3047                         pd_idx = sector_div(stripe2, raid_disks);
3048                         if (*dd_idx >= pd_idx)
3049                                 (*dd_idx)++;
3050                         break;
3051                 case ALGORITHM_LEFT_SYMMETRIC:
3052                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
3053                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
3054                         break;
3055                 case ALGORITHM_RIGHT_SYMMETRIC:
3056                         pd_idx = sector_div(stripe2, raid_disks);
3057                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
3058                         break;
3059                 case ALGORITHM_PARITY_0:
3060                         pd_idx = 0;
3061                         (*dd_idx)++;
3062                         break;
3063                 case ALGORITHM_PARITY_N:
3064                         pd_idx = data_disks;
3065                         break;
3066                 default:
3067                         BUG();
3068                 }
3069                 break;
3070         case 6:
3071
3072                 switch (algorithm) {
3073                 case ALGORITHM_LEFT_ASYMMETRIC:
3074                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3075                         qd_idx = pd_idx + 1;
3076                         if (pd_idx == raid_disks-1) {
3077                                 (*dd_idx)++;    /* Q D D D P */
3078                                 qd_idx = 0;
3079                         } else if (*dd_idx >= pd_idx)
3080                                 (*dd_idx) += 2; /* D D P Q D */
3081                         break;
3082                 case ALGORITHM_RIGHT_ASYMMETRIC:
3083                         pd_idx = sector_div(stripe2, raid_disks);
3084                         qd_idx = pd_idx + 1;
3085                         if (pd_idx == raid_disks-1) {
3086                                 (*dd_idx)++;    /* Q D D D P */
3087                                 qd_idx = 0;
3088                         } else if (*dd_idx >= pd_idx)
3089                                 (*dd_idx) += 2; /* D D P Q D */
3090                         break;
3091                 case ALGORITHM_LEFT_SYMMETRIC:
3092                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3093                         qd_idx = (pd_idx + 1) % raid_disks;
3094                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
3095                         break;
3096                 case ALGORITHM_RIGHT_SYMMETRIC:
3097                         pd_idx = sector_div(stripe2, raid_disks);
3098                         qd_idx = (pd_idx + 1) % raid_disks;
3099                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
3100                         break;
3101
3102                 case ALGORITHM_PARITY_0:
3103                         pd_idx = 0;
3104                         qd_idx = 1;
3105                         (*dd_idx) += 2;
3106                         break;
3107                 case ALGORITHM_PARITY_N:
3108                         pd_idx = data_disks;
3109                         qd_idx = data_disks + 1;
3110                         break;
3111
3112                 case ALGORITHM_ROTATING_ZERO_RESTART:
3113                         /* Exactly the same as RIGHT_ASYMMETRIC, but or
3114                          * of blocks for computing Q is different.
3115                          */
3116                         pd_idx = sector_div(stripe2, raid_disks);
3117                         qd_idx = pd_idx + 1;
3118                         if (pd_idx == raid_disks-1) {
3119                                 (*dd_idx)++;    /* Q D D D P */
3120                                 qd_idx = 0;
3121                         } else if (*dd_idx >= pd_idx)
3122                                 (*dd_idx) += 2; /* D D P Q D */
3123                         ddf_layout = 1;
3124                         break;
3125
3126                 case ALGORITHM_ROTATING_N_RESTART:
3127                         /* Same a left_asymmetric, by first stripe is
3128                          * D D D P Q  rather than
3129                          * Q D D D P
3130                          */
3131                         stripe2 += 1;
3132                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3133                         qd_idx = pd_idx + 1;
3134                         if (pd_idx == raid_disks-1) {
3135                                 (*dd_idx)++;    /* Q D D D P */
3136                                 qd_idx = 0;
3137                         } else if (*dd_idx >= pd_idx)
3138                                 (*dd_idx) += 2; /* D D P Q D */
3139                         ddf_layout = 1;
3140                         break;
3141
3142                 case ALGORITHM_ROTATING_N_CONTINUE:
3143                         /* Same as left_symmetric but Q is before P */
3144                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3145                         qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
3146                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
3147                         ddf_layout = 1;
3148                         break;
3149
3150                 case ALGORITHM_LEFT_ASYMMETRIC_6:
3151                         /* RAID5 left_asymmetric, with Q on last device */
3152                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
3153                         if (*dd_idx >= pd_idx)
3154                                 (*dd_idx)++;
3155                         qd_idx = raid_disks - 1;
3156                         break;
3157
3158                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
3159                         pd_idx = sector_div(stripe2, raid_disks-1);
3160                         if (*dd_idx >= pd_idx)
3161                                 (*dd_idx)++;
3162                         qd_idx = raid_disks - 1;
3163                         break;
3164
3165                 case ALGORITHM_LEFT_SYMMETRIC_6:
3166                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
3167                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
3168                         qd_idx = raid_disks - 1;
3169                         break;
3170
3171                 case ALGORITHM_RIGHT_SYMMETRIC_6:
3172                         pd_idx = sector_div(stripe2, raid_disks-1);
3173                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
3174                         qd_idx = raid_disks - 1;
3175                         break;
3176
3177                 case ALGORITHM_PARITY_0_6:
3178                         pd_idx = 0;
3179                         (*dd_idx)++;
3180                         qd_idx = raid_disks - 1;
3181                         break;
3182
3183                 default:
3184                         BUG();
3185                 }
3186                 break;
3187         }
3188
3189         if (sh) {
3190                 sh->pd_idx = pd_idx;
3191                 sh->qd_idx = qd_idx;
3192                 sh->ddf_layout = ddf_layout;
3193         }
3194         /*
3195          * Finally, compute the new sector number
3196          */
3197         new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
3198         return new_sector;
3199 }
3200
3201 sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous)
3202 {
3203         struct r5conf *conf = sh->raid_conf;
3204         int raid_disks = sh->disks;
3205         int data_disks = raid_disks - conf->max_degraded;
3206         sector_t new_sector = sh->sector, check;
3207         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
3208                                          : conf->chunk_sectors;
3209         int algorithm = previous ? conf->prev_algo
3210                                  : conf->algorithm;
3211         sector_t stripe;
3212         int chunk_offset;
3213         sector_t chunk_number;
3214         int dummy1, dd_idx = i;
3215         sector_t r_sector;
3216         struct stripe_head sh2;
3217
3218         chunk_offset = sector_div(new_sector, sectors_per_chunk);
3219         stripe = new_sector;
3220
3221         if (i == sh->pd_idx)
3222                 return 0;
3223         switch(conf->level) {
3224         case 4: break;
3225         case 5:
3226                 switch (algorithm) {
3227                 case ALGORITHM_LEFT_ASYMMETRIC:
3228                 case ALGORITHM_RIGHT_ASYMMETRIC:
3229                         if (i > sh->pd_idx)
3230                                 i--;
3231                         break;
3232                 case ALGORITHM_LEFT_SYMMETRIC:
3233                 case ALGORITHM_RIGHT_SYMMETRIC:
3234                         if (i < sh->pd_idx)
3235                                 i += raid_disks;
3236                         i -= (sh->pd_idx + 1);
3237                         break;
3238                 case ALGORITHM_PARITY_0:
3239                         i -= 1;
3240                         break;
3241                 case ALGORITHM_PARITY_N:
3242                         break;
3243                 default:
3244                         BUG();
3245                 }
3246                 break;
3247         case 6:
3248                 if (i == sh->qd_idx)
3249                         return 0; /* It is the Q disk */
3250                 switch (algorithm) {
3251                 case ALGORITHM_LEFT_ASYMMETRIC:
3252                 case ALGORITHM_RIGHT_ASYMMETRIC:
3253                 case ALGORITHM_ROTATING_ZERO_RESTART:
3254                 case ALGORITHM_ROTATING_N_RESTART:
3255                         if (sh->pd_idx == raid_disks-1)
3256                                 i--;    /* Q D D D P */
3257                         else if (i > sh->pd_idx)
3258                                 i -= 2; /* D D P Q D */
3259                         break;
3260                 case ALGORITHM_LEFT_SYMMETRIC:
3261                 case ALGORITHM_RIGHT_SYMMETRIC:
3262                         if (sh->pd_idx == raid_disks-1)
3263                                 i--; /* Q D D D P */
3264                         else {
3265                                 /* D D P Q D */
3266                                 if (i < sh->pd_idx)
3267                                         i += raid_disks;
3268                                 i -= (sh->pd_idx + 2);
3269                         }
3270                         break;
3271                 case ALGORITHM_PARITY_0:
3272                         i -= 2;
3273                         break;
3274                 case ALGORITHM_PARITY_N:
3275                         break;
3276                 case ALGORITHM_ROTATING_N_CONTINUE:
3277                         /* Like left_symmetric, but P is before Q */
3278                         if (sh->pd_idx == 0)
3279                                 i--;    /* P D D D Q */
3280                         else {
3281                                 /* D D Q P D */
3282                                 if (i < sh->pd_idx)
3283                                         i += raid_disks;
3284                                 i -= (sh->pd_idx + 1);
3285                         }
3286                         break;
3287                 case ALGORITHM_LEFT_ASYMMETRIC_6:
3288                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
3289                         if (i > sh->pd_idx)
3290                                 i--;
3291                         break;
3292                 case ALGORITHM_LEFT_SYMMETRIC_6:
3293                 case ALGORITHM_RIGHT_SYMMETRIC_6:
3294                         if (i < sh->pd_idx)
3295                                 i += data_disks + 1;
3296                         i -= (sh->pd_idx + 1);
3297                         break;
3298                 case ALGORITHM_PARITY_0_6:
3299                         i -= 1;
3300                         break;
3301                 default:
3302                         BUG();
3303                 }
3304                 break;
3305         }
3306
3307         chunk_number = stripe * data_disks + i;
3308         r_sector = chunk_number * sectors_per_chunk + chunk_offset;
3309
3310         check = raid5_compute_sector(conf, r_sector,
3311                                      previous, &dummy1, &sh2);
3312         if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
3313                 || sh2.qd_idx != sh->qd_idx) {
3314                 pr_warn("md/raid:%s: compute_blocknr: map not correct\n",
3315                         mdname(conf->mddev));
3316                 return 0;
3317         }
3318         return r_sector;
3319 }
3320
3321 /*
3322  * There are cases where we want handle_stripe_dirtying() and
3323  * schedule_reconstruction() to delay towrite to some dev of a stripe.
3324  *
3325  * This function checks whether we want to delay the towrite. Specifically,
3326  * we delay the towrite when:
3327  *
3328  *   1. degraded stripe has a non-overwrite to the missing dev, AND this
3329  *      stripe has data in journal (for other devices).
3330  *
3331  *      In this case, when reading data for the non-overwrite dev, it is
3332  *      necessary to handle complex rmw of write back cache (prexor with
3333  *      orig_page, and xor with page). To keep read path simple, we would
3334  *      like to flush data in journal to RAID disks first, so complex rmw
3335  *      is handled in the write patch (handle_stripe_dirtying).
3336  *
3337  *   2. when journal space is critical (R5C_LOG_CRITICAL=1)
3338  *
3339  *      It is important to be able to flush all stripes in raid5-cache.
3340  *      Therefore, we need reserve some space on the journal device for
3341  *      these flushes. If flush operation includes pending writes to the
3342  *      stripe, we need to reserve (conf->raid_disk + 1) pages per stripe
3343  *      for the flush out. If we exclude these pending writes from flush
3344  *      operation, we only need (conf->max_degraded + 1) pages per stripe.
3345  *      Therefore, excluding pending writes in these cases enables more
3346  *      efficient use of the journal device.
3347  *
3348  *      Note: To make sure the stripe makes progress, we only delay
3349  *      towrite for stripes with data already in journal (injournal > 0).
3350  *      When LOG_CRITICAL, stripes with injournal == 0 will be sent to
3351  *      no_space_stripes list.
3352  *
3353  *   3. during journal failure
3354  *      In journal failure, we try to flush all cached data to raid disks
3355  *      based on data in stripe cache. The array is read-only to upper
3356  *      layers, so we would skip all pending writes.
3357  *
3358  */
3359 static inline bool delay_towrite(struct r5conf *conf,
3360                                  struct r5dev *dev,
3361                                  struct stripe_head_state *s)
3362 {
3363         /* case 1 above */
3364         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3365             !test_bit(R5_Insync, &dev->flags) && s->injournal)
3366                 return true;
3367         /* case 2 above */
3368         if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
3369             s->injournal > 0)
3370                 return true;
3371         /* case 3 above */
3372         if (s->log_failed && s->injournal)
3373                 return true;
3374         return false;
3375 }
3376
3377 static void
3378 schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
3379                          int rcw, int expand)
3380 {
3381         int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx, disks = sh->disks;
3382         struct r5conf *conf = sh->raid_conf;
3383         int level = conf->level;
3384
3385         if (rcw) {
3386                 /*
3387                  * In some cases, handle_stripe_dirtying initially decided to
3388                  * run rmw and allocates extra page for prexor. However, rcw is
3389                  * cheaper later on. We need to free the extra page now,
3390                  * because we won't be able to do that in ops_complete_prexor().
3391                  */
3392                 r5c_release_extra_page(sh);
3393
3394                 for (i = disks; i--; ) {
3395                         struct r5dev *dev = &sh->dev[i];
3396
3397                         if (dev->towrite && !delay_towrite(conf, dev, s)) {
3398                                 set_bit(R5_LOCKED, &dev->flags);
3399                                 set_bit(R5_Wantdrain, &dev->flags);
3400                                 if (!expand)
3401                                         clear_bit(R5_UPTODATE, &dev->flags);
3402                                 s->locked++;
3403                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3404                                 set_bit(R5_LOCKED, &dev->flags);
3405                                 s->locked++;
3406                         }
3407                 }
3408                 /* if we are not expanding this is a proper write request, and
3409                  * there will be bios with new data to be drained into the
3410                  * stripe cache
3411                  */
3412                 if (!expand) {
3413                         if (!s->locked)
3414                                 /* False alarm, nothing to do */
3415                                 return;
3416                         sh->reconstruct_state = reconstruct_state_drain_run;
3417                         set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3418                 } else
3419                         sh->reconstruct_state = reconstruct_state_run;
3420
3421                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3422
3423                 if (s->locked + conf->max_degraded == disks)
3424                         if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
3425                                 atomic_inc(&conf->pending_full_writes);
3426         } else {
3427                 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
3428                         test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
3429                 BUG_ON(level == 6 &&
3430                         (!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
3431                            test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));
3432
3433                 for (i = disks; i--; ) {
3434                         struct r5dev *dev = &sh->dev[i];
3435                         if (i == pd_idx || i == qd_idx)
3436                                 continue;
3437
3438                         if (dev->towrite &&
3439                             (test_bit(R5_UPTODATE, &dev->flags) ||
3440                              test_bit(R5_Wantcompute, &dev->flags))) {
3441                                 set_bit(R5_Wantdrain, &dev->flags);
3442                                 set_bit(R5_LOCKED, &dev->flags);
3443                                 clear_bit(R5_UPTODATE, &dev->flags);
3444                                 s->locked++;
3445                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3446                                 set_bit(R5_LOCKED, &dev->flags);
3447                                 s->locked++;
3448                         }
3449                 }
3450                 if (!s->locked)
3451                         /* False alarm - nothing to do */
3452                         return;
3453                 sh->reconstruct_state = reconstruct_state_prexor_drain_run;
3454                 set_bit(STRIPE_OP_PREXOR, &s->ops_request);
3455                 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3456                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3457         }
3458
3459         /* keep the parity disk(s) locked while asynchronous operations
3460          * are in flight
3461          */
3462         set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
3463         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
3464         s->locked++;
3465
3466         if (level == 6) {
3467                 int qd_idx = sh->qd_idx;
3468                 struct r5dev *dev = &sh->dev[qd_idx];
3469
3470                 set_bit(R5_LOCKED, &dev->flags);
3471                 clear_bit(R5_UPTODATE, &dev->flags);
3472                 s->locked++;
3473         }
3474
3475         if (raid5_has_ppl(sh->raid_conf) && sh->ppl_page &&
3476             test_bit(STRIPE_OP_BIODRAIN, &s->ops_request) &&
3477             !test_bit(STRIPE_FULL_WRITE, &sh->state) &&
3478             test_bit(R5_Insync, &sh->dev[pd_idx].flags))
3479                 set_bit(STRIPE_OP_PARTIAL_PARITY, &s->ops_request);
3480
3481         pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
3482                 __func__, (unsigned long long)sh->sector,
3483                 s->locked, s->ops_request);
3484 }
3485
3486 static bool stripe_bio_overlaps(struct stripe_head *sh, struct bio *bi,
3487                                 int dd_idx, int forwrite)
3488 {
3489         struct r5conf *conf = sh->raid_conf;
3490         struct bio **bip;
3491
3492         pr_debug("checking bi b#%llu to stripe s#%llu\n",
3493                  bi->bi_iter.bi_sector, sh->sector);
3494
3495         /* Don't allow new IO added to stripes in batch list */
3496         if (sh->batch_head)
3497                 return true;
3498
3499         if (forwrite)
3500                 bip = &sh->dev[dd_idx].towrite;
3501         else
3502                 bip = &sh->dev[dd_idx].toread;
3503
3504         while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector) {
3505                 if (bio_end_sector(*bip) > bi->bi_iter.bi_sector)
3506                         return true;
3507                 bip = &(*bip)->bi_next;
3508         }
3509
3510         if (*bip && (*bip)->bi_iter.bi_sector < bio_end_sector(bi))
3511                 return true;
3512
3513         if (forwrite && raid5_has_ppl(conf)) {
3514                 /*
3515                  * With PPL only writes to consecutive data chunks within a
3516                  * stripe are allowed because for a single stripe_head we can
3517                  * only have one PPL entry at a time, which describes one data
3518                  * range. Not really an overlap, but wait_for_overlap can be
3519                  * used to handle this.
3520                  */
3521                 sector_t sector;
3522                 sector_t first = 0;
3523                 sector_t last = 0;
3524                 int count = 0;
3525                 int i;
3526
3527                 for (i = 0; i < sh->disks; i++) {
3528                         if (i != sh->pd_idx &&
3529                             (i == dd_idx || sh->dev[i].towrite)) {
3530                                 sector = sh->dev[i].sector;
3531                                 if (count == 0 || sector < first)
3532                                         first = sector;
3533                                 if (sector > last)
3534                                         last = sector;
3535                                 count++;
3536                         }
3537                 }
3538
3539                 if (first + conf->chunk_sectors * (count - 1) != last)
3540                         return true;
3541         }
3542
3543         return false;
3544 }
3545
3546 static void __add_stripe_bio(struct stripe_head *sh, struct bio *bi,
3547                              int dd_idx, int forwrite, int previous)
3548 {
3549         struct r5conf *conf = sh->raid_conf;
3550         struct bio **bip;
3551         int firstwrite = 0;
3552
3553         if (forwrite) {
3554                 bip = &sh->dev[dd_idx].towrite;
3555                 if (!*bip)
3556                         firstwrite = 1;
3557         } else {
3558                 bip = &sh->dev[dd_idx].toread;
3559         }
3560
3561         while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector)
3562                 bip = &(*bip)->bi_next;
3563
3564         if (!forwrite || previous)
3565                 clear_bit(STRIPE_BATCH_READY, &sh->state);
3566
3567         BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
3568         if (*bip)
3569                 bi->bi_next = *bip;
3570         *bip = bi;
3571         bio_inc_remaining(bi);
3572         md_write_inc(conf->mddev, bi);
3573
3574         if (forwrite) {
3575                 /* check if page is covered */
3576                 sector_t sector = sh->dev[dd_idx].sector;
3577                 for (bi=sh->dev[dd_idx].towrite;
3578                      sector < sh->dev[dd_idx].sector + RAID5_STRIPE_SECTORS(conf) &&
3579                              bi && bi->bi_iter.bi_sector <= sector;
3580                      bi = r5_next_bio(conf, bi, sh->dev[dd_idx].sector)) {
3581                         if (bio_end_sector(bi) >= sector)
3582                                 sector = bio_end_sector(bi);
3583                 }
3584                 if (sector >= sh->dev[dd_idx].sector + RAID5_STRIPE_SECTORS(conf))
3585                         if (!test_and_set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags))
3586                                 sh->overwrite_disks++;
3587         }
3588
3589         pr_debug("added bi b#%llu to stripe s#%llu, disk %d, logical %llu\n",
3590                  (*bip)->bi_iter.bi_sector, sh->sector, dd_idx,
3591                  sh->dev[dd_idx].sector);
3592
3593         if (conf->mddev->bitmap && firstwrite) {
3594                 /* Cannot hold spinlock over bitmap_startwrite,
3595                  * but must ensure this isn't added to a batch until
3596                  * we have added to the bitmap and set bm_seq.
3597                  * So set STRIPE_BITMAP_PENDING to prevent
3598                  * batching.
3599                  * If multiple __add_stripe_bio() calls race here they
3600                  * much all set STRIPE_BITMAP_PENDING.  So only the first one
3601                  * to complete "bitmap_startwrite" gets to set
3602                  * STRIPE_BIT_DELAY.  This is important as once a stripe
3603                  * is added to a batch, STRIPE_BIT_DELAY cannot be changed
3604                  * any more.
3605                  */
3606                 set_bit(STRIPE_BITMAP_PENDING, &sh->state);
3607                 spin_unlock_irq(&sh->stripe_lock);
3608                 md_bitmap_startwrite(conf->mddev->bitmap, sh->sector,
3609                                      RAID5_STRIPE_SECTORS(conf), 0);
3610                 spin_lock_irq(&sh->stripe_lock);
3611                 clear_bit(STRIPE_BITMAP_PENDING, &sh->state);
3612                 if (!sh->batch_head) {
3613                         sh->bm_seq = conf->seq_flush+1;
3614                         set_bit(STRIPE_BIT_DELAY, &sh->state);
3615                 }
3616         }
3617 }
3618
3619 /*
3620  * Each stripe/dev can have one or more bios attached.
3621  * toread/towrite point to the first in a chain.
3622  * The bi_next chain must be in order.
3623  */
3624 static bool add_stripe_bio(struct stripe_head *sh, struct bio *bi,
3625                            int dd_idx, int forwrite, int previous)
3626 {
3627         spin_lock_irq(&sh->stripe_lock);
3628
3629         if (stripe_bio_overlaps(sh, bi, dd_idx, forwrite)) {
3630                 set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
3631                 spin_unlock_irq(&sh->stripe_lock);
3632                 return false;
3633         }
3634
3635         __add_stripe_bio(sh, bi, dd_idx, forwrite, previous);
3636         spin_unlock_irq(&sh->stripe_lock);
3637         return true;
3638 }
3639
3640 static void end_reshape(struct r5conf *conf);
3641
3642 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
3643                             struct stripe_head *sh)
3644 {
3645         int sectors_per_chunk =
3646                 previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
3647         int dd_idx;
3648         int chunk_offset = sector_div(stripe, sectors_per_chunk);
3649         int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
3650
3651         raid5_compute_sector(conf,
3652                              stripe * (disks - conf->max_degraded)
3653                              *sectors_per_chunk + chunk_offset,
3654                              previous,
3655                              &dd_idx, sh);
3656 }
3657
3658 static void
3659 handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
3660                      struct stripe_head_state *s, int disks)
3661 {
3662         int i;
3663         BUG_ON(sh->batch_head);
3664         for (i = disks; i--; ) {
3665                 struct bio *bi;
3666                 int bitmap_end = 0;
3667
3668                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
3669                         struct md_rdev *rdev;
3670                         rcu_read_lock();
3671                         rdev = rcu_dereference(conf->disks[i].rdev);
3672                         if (rdev && test_bit(In_sync, &rdev->flags) &&
3673                             !test_bit(Faulty, &rdev->flags))
3674                                 atomic_inc(&rdev->nr_pending);
3675                         else
3676                                 rdev = NULL;
3677                         rcu_read_unlock();
3678                         if (rdev) {
3679                                 if (!rdev_set_badblocks(
3680                                             rdev,
3681                                             sh->sector,
3682                                             RAID5_STRIPE_SECTORS(conf), 0))
3683                                         md_error(conf->mddev, rdev);
3684                                 rdev_dec_pending(rdev, conf->mddev);
3685                         }
3686                 }
3687                 spin_lock_irq(&sh->stripe_lock);
3688                 /* fail all writes first */
3689                 bi = sh->dev[i].towrite;
3690                 sh->dev[i].towrite = NULL;
3691                 sh->overwrite_disks = 0;
3692                 spin_unlock_irq(&sh->stripe_lock);
3693                 if (bi)
3694                         bitmap_end = 1;
3695
3696                 log_stripe_write_finished(sh);
3697
3698                 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3699                         wake_up(&conf->wait_for_overlap);
3700
3701                 while (bi && bi->bi_iter.bi_sector <
3702                         sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3703                         struct bio *nextbi = r5_next_bio(conf, bi, sh->dev[i].sector);
3704
3705                         md_write_end(conf->mddev);
3706                         bio_io_error(bi);
3707                         bi = nextbi;
3708                 }
3709                 if (bitmap_end)
3710                         md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3711                                            RAID5_STRIPE_SECTORS(conf), 0, 0);
3712                 bitmap_end = 0;
3713                 /* and fail all 'written' */
3714                 bi = sh->dev[i].written;
3715                 sh->dev[i].written = NULL;
3716                 if (test_and_clear_bit(R5_SkipCopy, &sh->dev[i].flags)) {
3717                         WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
3718                         sh->dev[i].page = sh->dev[i].orig_page;
3719                 }
3720
3721                 if (bi) bitmap_end = 1;
3722                 while (bi && bi->bi_iter.bi_sector <
3723                        sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3724                         struct bio *bi2 = r5_next_bio(conf, bi, sh->dev[i].sector);
3725
3726                         md_write_end(conf->mddev);
3727                         bio_io_error(bi);
3728                         bi = bi2;
3729                 }
3730
3731                 /* fail any reads if this device is non-operational and
3732                  * the data has not reached the cache yet.
3733                  */
3734                 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
3735                     s->failed > conf->max_degraded &&
3736                     (!test_bit(R5_Insync, &sh->dev[i].flags) ||
3737                       test_bit(R5_ReadError, &sh->dev[i].flags))) {
3738                         spin_lock_irq(&sh->stripe_lock);
3739                         bi = sh->dev[i].toread;
3740                         sh->dev[i].toread = NULL;
3741                         spin_unlock_irq(&sh->stripe_lock);
3742                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3743                                 wake_up(&conf->wait_for_overlap);
3744                         if (bi)
3745                                 s->to_read--;
3746                         while (bi && bi->bi_iter.bi_sector <
3747                                sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3748                                 struct bio *nextbi =
3749                                         r5_next_bio(conf, bi, sh->dev[i].sector);
3750
3751                                 bio_io_error(bi);
3752                                 bi = nextbi;
3753                         }
3754                 }
3755                 if (bitmap_end)
3756                         md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3757                                            RAID5_STRIPE_SECTORS(conf), 0, 0);
3758                 /* If we were in the middle of a write the parity block might
3759                  * still be locked - so just clear all R5_LOCKED flags
3760                  */
3761                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
3762         }
3763         s->to_write = 0;
3764         s->written = 0;
3765
3766         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3767                 if (atomic_dec_and_test(&conf->pending_full_writes))
3768                         md_wakeup_thread(conf->mddev->thread);
3769 }
3770
3771 static void
3772 handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
3773                    struct stripe_head_state *s)
3774 {
3775         int abort = 0;
3776         int i;
3777
3778         BUG_ON(sh->batch_head);
3779         clear_bit(STRIPE_SYNCING, &sh->state);
3780         if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
3781                 wake_up(&conf->wait_for_overlap);
3782         s->syncing = 0;
3783         s->replacing = 0;
3784         /* There is nothing more to do for sync/check/repair.
3785          * Don't even need to abort as that is handled elsewhere
3786          * if needed, and not always wanted e.g. if there is a known
3787          * bad block here.
3788          * For recover/replace we need to record a bad block on all
3789          * non-sync devices, or abort the recovery
3790          */
3791         if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
3792                 /* During recovery devices cannot be removed, so
3793                  * locking and refcounting of rdevs is not needed
3794                  */
3795                 rcu_read_lock();
3796                 for (i = 0; i < conf->raid_disks; i++) {
3797                         struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
3798                         if (rdev
3799                             && !test_bit(Faulty, &rdev->flags)
3800                             && !test_bit(In_sync, &rdev->flags)
3801                             && !rdev_set_badblocks(rdev, sh->sector,
3802                                                    RAID5_STRIPE_SECTORS(conf), 0))
3803                                 abort = 1;
3804                         rdev = rcu_dereference(conf->disks[i].replacement);
3805                         if (rdev
3806                             && !test_bit(Faulty, &rdev->flags)
3807                             && !test_bit(In_sync, &rdev->flags)
3808                             && !rdev_set_badblocks(rdev, sh->sector,
3809                                                    RAID5_STRIPE_SECTORS(conf), 0))
3810                                 abort = 1;
3811                 }
3812                 rcu_read_unlock();
3813                 if (abort)
3814                         conf->recovery_disabled =
3815                                 conf->mddev->recovery_disabled;
3816         }
3817         md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), !abort);
3818 }
3819
3820 static int want_replace(struct stripe_head *sh, int disk_idx)
3821 {
3822         struct md_rdev *rdev;
3823         int rv = 0;
3824
3825         rcu_read_lock();
3826         rdev = rcu_dereference(sh->raid_conf->disks[disk_idx].replacement);
3827         if (rdev
3828             && !test_bit(Faulty, &rdev->flags)
3829             && !test_bit(In_sync, &rdev->flags)
3830             && (rdev->recovery_offset <= sh->sector
3831                 || rdev->mddev->recovery_cp <= sh->sector))
3832                 rv = 1;
3833         rcu_read_unlock();
3834         return rv;
3835 }
3836
3837 static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
3838                            int disk_idx, int disks)
3839 {
3840         struct r5dev *dev = &sh->dev[disk_idx];
3841         struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
3842                                   &sh->dev[s->failed_num[1]] };
3843         int i;
3844         bool force_rcw = (sh->raid_conf->rmw_level == PARITY_DISABLE_RMW);
3845
3846
3847         if (test_bit(R5_LOCKED, &dev->flags) ||
3848             test_bit(R5_UPTODATE, &dev->flags))
3849                 /* No point reading this as we already have it or have
3850                  * decided to get it.
3851                  */
3852                 return 0;
3853
3854         if (dev->toread ||
3855             (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)))
3856                 /* We need this block to directly satisfy a request */
3857                 return 1;
3858
3859         if (s->syncing || s->expanding ||
3860             (s->replacing && want_replace(sh, disk_idx)))
3861                 /* When syncing, or expanding we read everything.
3862                  * When replacing, we need the replaced block.
3863                  */
3864                 return 1;
3865
3866         if ((s->failed >= 1 && fdev[0]->toread) ||
3867             (s->failed >= 2 && fdev[1]->toread))
3868                 /* If we want to read from a failed device, then
3869                  * we need to actually read every other device.
3870                  */
3871                 return 1;
3872
3873         /* Sometimes neither read-modify-write nor reconstruct-write
3874          * cycles can work.  In those cases we read every block we
3875          * can.  Then the parity-update is certain to have enough to
3876          * work with.
3877          * This can only be a problem when we need to write something,
3878          * and some device has failed.  If either of those tests
3879          * fail we need look no further.
3880          */
3881         if (!s->failed || !s->to_write)
3882                 return 0;
3883
3884         if (test_bit(R5_Insync, &dev->flags) &&
3885             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3886                 /* Pre-reads at not permitted until after short delay
3887                  * to gather multiple requests.  However if this
3888                  * device is no Insync, the block could only be computed
3889                  * and there is no need to delay that.
3890                  */
3891                 return 0;
3892
3893         for (i = 0; i < s->failed && i < 2; i++) {
3894                 if (fdev[i]->towrite &&
3895                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3896                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3897                         /* If we have a partial write to a failed
3898                          * device, then we will need to reconstruct
3899                          * the content of that device, so all other
3900                          * devices must be read.
3901                          */
3902                         return 1;
3903
3904                 if (s->failed >= 2 &&
3905                     (fdev[i]->towrite ||
3906                      s->failed_num[i] == sh->pd_idx ||
3907                      s->failed_num[i] == sh->qd_idx) &&
3908                     !test_bit(R5_UPTODATE, &fdev[i]->flags))
3909                         /* In max degraded raid6, If the failed disk is P, Q,
3910                          * or we want to read the failed disk, we need to do
3911                          * reconstruct-write.
3912                          */
3913                         force_rcw = true;
3914         }
3915
3916         /* If we are forced to do a reconstruct-write, because parity
3917          * cannot be trusted and we are currently recovering it, there
3918          * is extra need to be careful.
3919          * If one of the devices that we would need to read, because
3920          * it is not being overwritten (and maybe not written at all)
3921          * is missing/faulty, then we need to read everything we can.
3922          */
3923         if (!force_rcw &&
3924             sh->sector < sh->raid_conf->mddev->recovery_cp)
3925                 /* reconstruct-write isn't being forced */
3926                 return 0;
3927         for (i = 0; i < s->failed && i < 2; i++) {
3928                 if (s->failed_num[i] != sh->pd_idx &&
3929                     s->failed_num[i] != sh->qd_idx &&
3930                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3931                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3932                         return 1;
3933         }
3934
3935         return 0;
3936 }
3937
3938 /* fetch_block - checks the given member device to see if its data needs
3939  * to be read or computed to satisfy a request.
3940  *
3941  * Returns 1 when no more member devices need to be checked, otherwise returns
3942  * 0 to tell the loop in handle_stripe_fill to continue
3943  */
3944 static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
3945                        int disk_idx, int disks)
3946 {
3947         struct r5dev *dev = &sh->dev[disk_idx];
3948
3949         /* is the data in this block needed, and can we get it? */
3950         if (need_this_block(sh, s, disk_idx, disks)) {
3951                 /* we would like to get this block, possibly by computing it,
3952                  * otherwise read it if the backing disk is insync
3953                  */
3954                 BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
3955                 BUG_ON(test_bit(R5_Wantread, &dev->flags));
3956                 BUG_ON(sh->batch_head);
3957
3958                 /*
3959                  * In the raid6 case if the only non-uptodate disk is P
3960                  * then we already trusted P to compute the other failed
3961                  * drives. It is safe to compute rather than re-read P.
3962                  * In other cases we only compute blocks from failed
3963                  * devices, otherwise check/repair might fail to detect
3964                  * a real inconsistency.
3965                  */
3966
3967                 if ((s->uptodate == disks - 1) &&
3968                     ((sh->qd_idx >= 0 && sh->pd_idx == disk_idx) ||
3969                     (s->failed && (disk_idx == s->failed_num[0] ||
3970                                    disk_idx == s->failed_num[1])))) {
3971                         /* have disk failed, and we're requested to fetch it;
3972                          * do compute it
3973                          */
3974                         pr_debug("Computing stripe %llu block %d\n",
3975                                (unsigned long long)sh->sector, disk_idx);
3976                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3977                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3978                         set_bit(R5_Wantcompute, &dev->flags);
3979                         sh->ops.target = disk_idx;
3980                         sh->ops.target2 = -1; /* no 2nd target */
3981                         s->req_compute = 1;
3982                         /* Careful: from this point on 'uptodate' is in the eye
3983                          * of raid_run_ops which services 'compute' operations
3984                          * before writes. R5_Wantcompute flags a block that will
3985                          * be R5_UPTODATE by the time it is needed for a
3986                          * subsequent operation.
3987                          */
3988                         s->uptodate++;
3989                         return 1;
3990                 } else if (s->uptodate == disks-2 && s->failed >= 2) {
3991                         /* Computing 2-failure is *very* expensive; only
3992                          * do it if failed >= 2
3993                          */
3994                         int other;
3995                         for (other = disks; other--; ) {
3996                                 if (other == disk_idx)
3997                                         continue;
3998                                 if (!test_bit(R5_UPTODATE,
3999                                       &sh->dev[other].flags))
4000                                         break;
4001                         }
4002                         BUG_ON(other < 0);
4003                         pr_debug("Computing stripe %llu blocks %d,%d\n",
4004                                (unsigned long long)sh->sector,
4005                                disk_idx, other);
4006                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4007                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4008                         set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
4009                         set_bit(R5_Wantcompute, &sh->dev[other].flags);
4010                         sh->ops.target = disk_idx;
4011                         sh->ops.target2 = other;
4012                         s->uptodate += 2;
4013                         s->req_compute = 1;
4014                         return 1;
4015                 } else if (test_bit(R5_Insync, &dev->flags)) {
4016                         set_bit(R5_LOCKED, &dev->flags);
4017                         set_bit(R5_Wantread, &dev->flags);
4018                         s->locked++;
4019                         pr_debug("Reading block %d (sync=%d)\n",
4020                                 disk_idx, s->syncing);
4021                 }
4022         }
4023
4024         return 0;
4025 }
4026
4027 /*
4028  * handle_stripe_fill - read or compute data to satisfy pending requests.
4029  */
4030 static void handle_stripe_fill(struct stripe_head *sh,
4031                                struct stripe_head_state *s,
4032                                int disks)
4033 {
4034         int i;
4035
4036         /* look for blocks to read/compute, skip this if a compute
4037          * is already in flight, or if the stripe contents are in the
4038          * midst of changing due to a write
4039          */
4040         if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
4041             !sh->reconstruct_state) {
4042
4043                 /*
4044                  * For degraded stripe with data in journal, do not handle
4045                  * read requests yet, instead, flush the stripe to raid
4046                  * disks first, this avoids handling complex rmw of write
4047                  * back cache (prexor with orig_page, and then xor with
4048                  * page) in the read path
4049                  */
4050                 if (s->injournal && s->failed) {
4051                         if (test_bit(STRIPE_R5C_CACHING, &sh->state))
4052                                 r5c_make_stripe_write_out(sh);
4053                         goto out;
4054                 }
4055
4056                 for (i = disks; i--; )
4057                         if (fetch_block(sh, s, i, disks))
4058                                 break;
4059         }
4060 out:
4061         set_bit(STRIPE_HANDLE, &sh->state);
4062 }
4063
4064 static void break_stripe_batch_list(struct stripe_head *head_sh,
4065                                     unsigned long handle_flags);
4066 /* handle_stripe_clean_event
4067  * any written block on an uptodate or failed drive can be returned.
4068  * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
4069  * never LOCKED, so we don't need to test 'failed' directly.
4070  */
4071 static void handle_stripe_clean_event(struct r5conf *conf,
4072         struct stripe_head *sh, int disks)
4073 {
4074         int i;
4075         struct r5dev *dev;
4076         int discard_pending = 0;
4077         struct stripe_head *head_sh = sh;
4078         bool do_endio = false;
4079
4080         for (i = disks; i--; )
4081                 if (sh->dev[i].written) {
4082                         dev = &sh->dev[i];
4083                         if (!test_bit(R5_LOCKED, &dev->flags) &&
4084                             (test_bit(R5_UPTODATE, &dev->flags) ||
4085                              test_bit(R5_Discard, &dev->flags) ||
4086                              test_bit(R5_SkipCopy, &dev->flags))) {
4087                                 /* We can return any write requests */
4088                                 struct bio *wbi, *wbi2;
4089                                 pr_debug("Return write for disc %d\n", i);
4090                                 if (test_and_clear_bit(R5_Discard, &dev->flags))
4091                                         clear_bit(R5_UPTODATE, &dev->flags);
4092                                 if (test_and_clear_bit(R5_SkipCopy, &dev->flags)) {
4093                                         WARN_ON(test_bit(R5_UPTODATE, &dev->flags));
4094                                 }
4095                                 do_endio = true;
4096
4097 returnbi:
4098                                 dev->page = dev->orig_page;
4099                                 wbi = dev->written;
4100                                 dev->written = NULL;
4101                                 while (wbi && wbi->bi_iter.bi_sector <
4102                                         dev->sector + RAID5_STRIPE_SECTORS(conf)) {
4103                                         wbi2 = r5_next_bio(conf, wbi, dev->sector);
4104                                         md_write_end(conf->mddev);
4105                                         bio_endio(wbi);
4106                                         wbi = wbi2;
4107                                 }
4108                                 md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
4109                                                    RAID5_STRIPE_SECTORS(conf),
4110                                                    !test_bit(STRIPE_DEGRADED, &sh->state),
4111                                                    0);
4112                                 if (head_sh->batch_head) {
4113                                         sh = list_first_entry(&sh->batch_list,
4114                                                               struct stripe_head,
4115                                                               batch_list);
4116                                         if (sh != head_sh) {
4117                                                 dev = &sh->dev[i];
4118                                                 goto returnbi;
4119                                         }
4120                                 }
4121                                 sh = head_sh;
4122                                 dev = &sh->dev[i];
4123                         } else if (test_bit(R5_Discard, &dev->flags))
4124                                 discard_pending = 1;
4125                 }
4126
4127         log_stripe_write_finished(sh);
4128
4129         if (!discard_pending &&
4130             test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) {
4131                 int hash;
4132                 clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
4133                 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4134                 if (sh->qd_idx >= 0) {
4135                         clear_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
4136                         clear_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags);
4137                 }
4138                 /* now that discard is done we can proceed with any sync */
4139                 clear_bit(STRIPE_DISCARD, &sh->state);
4140                 /*
4141                  * SCSI discard will change some bio fields and the stripe has
4142                  * no updated data, so remove it from hash list and the stripe
4143                  * will be reinitialized
4144                  */
4145 unhash:
4146                 hash = sh->hash_lock_index;
4147                 spin_lock_irq(conf->hash_locks + hash);
4148                 remove_hash(sh);
4149                 spin_unlock_irq(conf->hash_locks + hash);
4150                 if (head_sh->batch_head) {
4151                         sh = list_first_entry(&sh->batch_list,
4152                                               struct stripe_head, batch_list);
4153                         if (sh != head_sh)
4154                                         goto unhash;
4155                 }
4156                 sh = head_sh;
4157
4158                 if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
4159                         set_bit(STRIPE_HANDLE, &sh->state);
4160
4161         }
4162
4163         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
4164                 if (atomic_dec_and_test(&conf->pending_full_writes))
4165                         md_wakeup_thread(conf->mddev->thread);
4166
4167         if (head_sh->batch_head && do_endio)
4168                 break_stripe_batch_list(head_sh, STRIPE_EXPAND_SYNC_FLAGS);
4169 }
4170
4171 /*
4172  * For RMW in write back cache, we need extra page in prexor to store the
4173  * old data. This page is stored in dev->orig_page.
4174  *
4175  * This function checks whether we have data for prexor. The exact logic
4176  * is:
4177  *       R5_UPTODATE && (!R5_InJournal || R5_OrigPageUPTDODATE)
4178  */
4179 static inline bool uptodate_for_rmw(struct r5dev *dev)
4180 {
4181         return (test_bit(R5_UPTODATE, &dev->flags)) &&
4182                 (!test_bit(R5_InJournal, &dev->flags) ||
4183                  test_bit(R5_OrigPageUPTDODATE, &dev->flags));
4184 }
4185
4186 static int handle_stripe_dirtying(struct r5conf *conf,
4187                                   struct stripe_head *sh,
4188                                   struct stripe_head_state *s,
4189                                   int disks)
4190 {
4191         int rmw = 0, rcw = 0, i;
4192         sector_t recovery_cp = conf->mddev->recovery_cp;
4193
4194         /* Check whether resync is now happening or should start.
4195          * If yes, then the array is dirty (after unclean shutdown or
4196          * initial creation), so parity in some stripes might be inconsistent.
4197          * In this case, we need to always do reconstruct-write, to ensure
4198          * that in case of drive failure or read-error correction, we
4199          * generate correct data from the parity.
4200          */
4201         if (conf->rmw_level == PARITY_DISABLE_RMW ||
4202             (recovery_cp < MaxSector && sh->sector >= recovery_cp &&
4203              s->failed == 0)) {
4204                 /* Calculate the real rcw later - for now make it
4205                  * look like rcw is cheaper
4206                  */
4207                 rcw = 1; rmw = 2;
4208                 pr_debug("force RCW rmw_level=%u, recovery_cp=%llu sh->sector=%llu\n",
4209                          conf->rmw_level, (unsigned long long)recovery_cp,
4210                          (unsigned long long)sh->sector);
4211         } else for (i = disks; i--; ) {
4212                 /* would I have to read this buffer for read_modify_write */
4213                 struct r5dev *dev = &sh->dev[i];
4214                 if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
4215                      i == sh->pd_idx || i == sh->qd_idx ||
4216                      test_bit(R5_InJournal, &dev->flags)) &&
4217                     !test_bit(R5_LOCKED, &dev->flags) &&
4218                     !(uptodate_for_rmw(dev) ||
4219                       test_bit(R5_Wantcompute, &dev->flags))) {
4220                         if (test_bit(R5_Insync, &dev->flags))
4221                                 rmw++;
4222                         else
4223                                 rmw += 2*disks;  /* cannot read it */
4224                 }
4225                 /* Would I have to read this buffer for reconstruct_write */
4226                 if (!test_bit(R5_OVERWRITE, &dev->flags) &&
4227                     i != sh->pd_idx && i != sh->qd_idx &&
4228                     !test_bit(R5_LOCKED, &dev->flags) &&
4229                     !(test_bit(R5_UPTODATE, &dev->flags) ||
4230                       test_bit(R5_Wantcompute, &dev->flags))) {
4231                         if (test_bit(R5_Insync, &dev->flags))
4232                                 rcw++;
4233                         else
4234                                 rcw += 2*disks;
4235                 }
4236         }
4237
4238         pr_debug("for sector %llu state 0x%lx, rmw=%d rcw=%d\n",
4239                  (unsigned long long)sh->sector, sh->state, rmw, rcw);
4240         set_bit(STRIPE_HANDLE, &sh->state);
4241         if ((rmw < rcw || (rmw == rcw && conf->rmw_level == PARITY_PREFER_RMW)) && rmw > 0) {
4242                 /* prefer read-modify-write, but need to get some data */
4243                 if (conf->mddev->queue)
4244                         blk_add_trace_msg(conf->mddev->queue,
4245                                           "raid5 rmw %llu %d",
4246                                           (unsigned long long)sh->sector, rmw);
4247                 for (i = disks; i--; ) {
4248                         struct r5dev *dev = &sh->dev[i];
4249                         if (test_bit(R5_InJournal, &dev->flags) &&
4250                             dev->page == dev->orig_page &&
4251                             !test_bit(R5_LOCKED, &sh->dev[sh->pd_idx].flags)) {
4252                                 /* alloc page for prexor */
4253                                 struct page *p = alloc_page(GFP_NOIO);
4254
4255                                 if (p) {
4256                                         dev->orig_page = p;
4257                                         continue;
4258                                 }
4259
4260                                 /*
4261                                  * alloc_page() failed, try use
4262                                  * disk_info->extra_page
4263                                  */
4264                                 if (!test_and_set_bit(R5C_EXTRA_PAGE_IN_USE,
4265                                                       &conf->cache_state)) {
4266                                         r5c_use_extra_page(sh);
4267                                         break;
4268                                 }
4269
4270                                 /* extra_page in use, add to delayed_list */
4271                                 set_bit(STRIPE_DELAYED, &sh->state);
4272                                 s->waiting_extra_page = 1;
4273                                 return -EAGAIN;
4274                         }
4275                 }
4276
4277                 for (i = disks; i--; ) {
4278                         struct r5dev *dev = &sh->dev[i];
4279                         if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
4280                              i == sh->pd_idx || i == sh->qd_idx ||
4281                              test_bit(R5_InJournal, &dev->flags)) &&
4282                             !test_bit(R5_LOCKED, &dev->flags) &&
4283                             !(uptodate_for_rmw(dev) ||
4284                               test_bit(R5_Wantcompute, &dev->flags)) &&
4285                             test_bit(R5_Insync, &dev->flags)) {
4286                                 if (test_bit(STRIPE_PREREAD_ACTIVE,
4287                                              &sh->state)) {
4288                                         pr_debug("Read_old block %d for r-m-w\n",
4289                                                  i);
4290                                         set_bit(R5_LOCKED, &dev->flags);
4291                                         set_bit(R5_Wantread, &dev->flags);
4292                                         s->locked++;
4293                                 } else
4294                                         set_bit(STRIPE_DELAYED, &sh->state);
4295                         }
4296                 }
4297         }
4298         if ((rcw < rmw || (rcw == rmw && conf->rmw_level != PARITY_PREFER_RMW)) && rcw > 0) {
4299                 /* want reconstruct write, but need to get some data */
4300                 int qread =0;
4301                 rcw = 0;
4302                 for (i = disks; i--; ) {
4303                         struct r5dev *dev = &sh->dev[i];
4304                         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
4305                             i != sh->pd_idx && i != sh->qd_idx &&
4306                             !test_bit(R5_LOCKED, &dev->flags) &&
4307                             !(test_bit(R5_UPTODATE, &dev->flags) ||
4308                               test_bit(R5_Wantcompute, &dev->flags))) {
4309                                 rcw++;
4310                                 if (test_bit(R5_Insync, &dev->flags) &&
4311                                     test_bit(STRIPE_PREREAD_ACTIVE,
4312                                              &sh->state)) {
4313                                         pr_debug("Read_old block "
4314                                                 "%d for Reconstruct\n", i);
4315                                         set_bit(R5_LOCKED, &dev->flags);
4316                                         set_bit(R5_Wantread, &dev->flags);
4317                                         s->locked++;
4318                                         qread++;
4319                                 } else
4320                                         set_bit(STRIPE_DELAYED, &sh->state);
4321                         }
4322                 }
4323                 if (rcw && conf->mddev->queue)
4324                         blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
4325                                           (unsigned long long)sh->sector,
4326                                           rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
4327         }
4328
4329         if (rcw > disks && rmw > disks &&
4330             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4331                 set_bit(STRIPE_DELAYED, &sh->state);
4332
4333         /* now if nothing is locked, and if we have enough data,
4334          * we can start a write request
4335          */
4336         /* since handle_stripe can be called at any time we need to handle the
4337          * case where a compute block operation has been submitted and then a
4338          * subsequent call wants to start a write request.  raid_run_ops only
4339          * handles the case where compute block and reconstruct are requested
4340          * simultaneously.  If this is not the case then new writes need to be
4341          * held off until the compute completes.
4342          */
4343         if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
4344             (s->locked == 0 && (rcw == 0 || rmw == 0) &&
4345              !test_bit(STRIPE_BIT_DELAY, &sh->state)))
4346                 schedule_reconstruction(sh, s, rcw == 0, 0);
4347         return 0;
4348 }
4349
4350 static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
4351                                 struct stripe_head_state *s, int disks)
4352 {
4353         struct r5dev *dev = NULL;
4354
4355         BUG_ON(sh->batch_head);
4356         set_bit(STRIPE_HANDLE, &sh->state);
4357
4358         switch (sh->check_state) {
4359         case check_state_idle:
4360                 /* start a new check operation if there are no failures */
4361                 if (s->failed == 0) {
4362                         BUG_ON(s->uptodate != disks);
4363                         sh->check_state = check_state_run;
4364                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4365                         clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4366                         s->uptodate--;
4367                         break;
4368                 }
4369                 dev = &sh->dev[s->failed_num[0]];
4370                 fallthrough;
4371         case check_state_compute_result:
4372                 sh->check_state = check_state_idle;
4373                 if (!dev)
4374                         dev = &sh->dev[sh->pd_idx];
4375
4376                 /* check that a write has not made the stripe insync */
4377                 if (test_bit(STRIPE_INSYNC, &sh->state))
4378                         break;
4379
4380                 /* either failed parity check, or recovery is happening */
4381                 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
4382                 BUG_ON(s->uptodate != disks);
4383
4384                 set_bit(R5_LOCKED, &dev->flags);
4385                 s->locked++;
4386                 set_bit(R5_Wantwrite, &dev->flags);
4387
4388                 clear_bit(STRIPE_DEGRADED, &sh->state);
4389                 set_bit(STRIPE_INSYNC, &sh->state);
4390                 break;
4391         case check_state_run:
4392                 break; /* we will be called again upon completion */
4393         case check_state_check_result:
4394                 sh->check_state = check_state_idle;
4395
4396                 /* if a failure occurred during the check operation, leave
4397                  * STRIPE_INSYNC not set and let the stripe be handled again
4398                  */
4399                 if (s->failed)
4400                         break;
4401
4402                 /* handle a successful check operation, if parity is correct
4403                  * we are done.  Otherwise update the mismatch count and repair
4404                  * parity if !MD_RECOVERY_CHECK
4405                  */
4406                 if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
4407                         /* parity is correct (on disc,
4408                          * not in buffer any more)
4409                          */
4410                         set_bit(STRIPE_INSYNC, &sh->state);
4411                 else {
4412                         atomic64_add(RAID5_STRIPE_SECTORS(conf), &conf->mddev->resync_mismatches);
4413                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4414                                 /* don't try to repair!! */
4415                                 set_bit(STRIPE_INSYNC, &sh->state);
4416                                 pr_warn_ratelimited("%s: mismatch sector in range "
4417                                                     "%llu-%llu\n", mdname(conf->mddev),
4418                                                     (unsigned long long) sh->sector,
4419                                                     (unsigned long long) sh->sector +
4420                                                     RAID5_STRIPE_SECTORS(conf));
4421                         } else {
4422                                 sh->check_state = check_state_compute_run;
4423                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4424                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4425                                 set_bit(R5_Wantcompute,
4426                                         &sh->dev[sh->pd_idx].flags);
4427                                 sh->ops.target = sh->pd_idx;
4428                                 sh->ops.target2 = -1;
4429                                 s->uptodate++;
4430                         }
4431                 }
4432                 break;
4433         case check_state_compute_run:
4434                 break;
4435         default:
4436                 pr_err("%s: unknown check_state: %d sector: %llu\n",
4437                        __func__, sh->check_state,
4438                        (unsigned long long) sh->sector);
4439                 BUG();
4440         }
4441 }
4442
4443 static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
4444                                   struct stripe_head_state *s,
4445                                   int disks)
4446 {
4447         int pd_idx = sh->pd_idx;
4448         int qd_idx = sh->qd_idx;
4449         struct r5dev *dev;
4450
4451         BUG_ON(sh->batch_head);
4452         set_bit(STRIPE_HANDLE, &sh->state);
4453
4454         BUG_ON(s->failed > 2);
4455
4456         /* Want to check and possibly repair P and Q.
4457          * However there could be one 'failed' device, in which
4458          * case we can only check one of them, possibly using the
4459          * other to generate missing data
4460          */
4461
4462         switch (sh->check_state) {
4463         case check_state_idle:
4464                 /* start a new check operation if there are < 2 failures */
4465                 if (s->failed == s->q_failed) {
4466                         /* The only possible failed device holds Q, so it
4467                          * makes sense to check P (If anything else were failed,
4468                          * we would have used P to recreate it).
4469                          */
4470                         sh->check_state = check_state_run;
4471                 }
4472                 if (!s->q_failed && s->failed < 2) {
4473                         /* Q is not failed, and we didn't use it to generate
4474                          * anything, so it makes sense to check it
4475                          */
4476                         if (sh->check_state == check_state_run)
4477                                 sh->check_state = check_state_run_pq;
4478                         else
4479                                 sh->check_state = check_state_run_q;
4480                 }
4481
4482                 /* discard potentially stale zero_sum_result */
4483                 sh->ops.zero_sum_result = 0;
4484
4485                 if (sh->check_state == check_state_run) {
4486                         /* async_xor_zero_sum destroys the contents of P */
4487                         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
4488                         s->uptodate--;
4489                 }
4490                 if (sh->check_state >= check_state_run &&
4491                     sh->check_state <= check_state_run_pq) {
4492                         /* async_syndrome_zero_sum preserves P and Q, so
4493                          * no need to mark them !uptodate here
4494                          */
4495                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4496                         break;
4497                 }
4498
4499                 /* we have 2-disk failure */
4500                 BUG_ON(s->failed != 2);
4501                 fallthrough;
4502         case check_state_compute_result:
4503                 sh->check_state = check_state_idle;
4504
4505                 /* check that a write has not made the stripe insync */
4506                 if (test_bit(STRIPE_INSYNC, &sh->state))
4507                         break;
4508
4509                 /* now write out any block on a failed drive,
4510                  * or P or Q if they were recomputed
4511                  */
4512                 dev = NULL;
4513                 if (s->failed == 2) {
4514                         dev = &sh->dev[s->failed_num[1]];
4515                         s->locked++;
4516                         set_bit(R5_LOCKED, &dev->flags);
4517                         set_bit(R5_Wantwrite, &dev->flags);
4518                 }
4519                 if (s->failed >= 1) {
4520                         dev = &sh->dev[s->failed_num[0]];
4521                         s->locked++;
4522                         set_bit(R5_LOCKED, &dev->flags);
4523                         set_bit(R5_Wantwrite, &dev->flags);
4524                 }
4525                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4526                         dev = &sh->dev[pd_idx];
4527                         s->locked++;
4528                         set_bit(R5_LOCKED, &dev->flags);
4529                         set_bit(R5_Wantwrite, &dev->flags);
4530                 }
4531                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4532                         dev = &sh->dev[qd_idx];
4533                         s->locked++;
4534                         set_bit(R5_LOCKED, &dev->flags);
4535                         set_bit(R5_Wantwrite, &dev->flags);
4536                 }
4537                 if (WARN_ONCE(dev && !test_bit(R5_UPTODATE, &dev->flags),
4538                               "%s: disk%td not up to date\n",
4539                               mdname(conf->mddev),
4540                               dev - (struct r5dev *) &sh->dev)) {
4541                         clear_bit(R5_LOCKED, &dev->flags);
4542                         clear_bit(R5_Wantwrite, &dev->flags);
4543                         s->locked--;
4544                 }
4545                 clear_bit(STRIPE_DEGRADED, &sh->state);
4546
4547                 set_bit(STRIPE_INSYNC, &sh->state);
4548                 break;
4549         case check_state_run:
4550         case check_state_run_q:
4551         case check_state_run_pq:
4552                 break; /* we will be called again upon completion */
4553         case check_state_check_result:
4554                 sh->check_state = check_state_idle;
4555
4556                 /* handle a successful check operation, if parity is correct
4557                  * we are done.  Otherwise update the mismatch count and repair
4558                  * parity if !MD_RECOVERY_CHECK
4559                  */
4560                 if (sh->ops.zero_sum_result == 0) {
4561                         /* both parities are correct */
4562                         if (!s->failed)
4563                                 set_bit(STRIPE_INSYNC, &sh->state);
4564                         else {
4565                                 /* in contrast to the raid5 case we can validate
4566                                  * parity, but still have a failure to write
4567                                  * back
4568                                  */
4569                                 sh->check_state = check_state_compute_result;
4570                                 /* Returning at this point means that we may go
4571                                  * off and bring p and/or q uptodate again so
4572                                  * we make sure to check zero_sum_result again
4573                                  * to verify if p or q need writeback
4574                                  */
4575                         }
4576                 } else {
4577                         atomic64_add(RAID5_STRIPE_SECTORS(conf), &conf->mddev->resync_mismatches);
4578                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4579                                 /* don't try to repair!! */
4580                                 set_bit(STRIPE_INSYNC, &sh->state);
4581                                 pr_warn_ratelimited("%s: mismatch sector in range "
4582                                                     "%llu-%llu\n", mdname(conf->mddev),
4583                                                     (unsigned long long) sh->sector,
4584                                                     (unsigned long long) sh->sector +
4585                                                     RAID5_STRIPE_SECTORS(conf));
4586                         } else {
4587                                 int *target = &sh->ops.target;
4588
4589                                 sh->ops.target = -1;
4590                                 sh->ops.target2 = -1;
4591                                 sh->check_state = check_state_compute_run;
4592                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4593                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4594                                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4595                                         set_bit(R5_Wantcompute,
4596                                                 &sh->dev[pd_idx].flags);
4597                                         *target = pd_idx;
4598                                         target = &sh->ops.target2;
4599                                         s->uptodate++;
4600                                 }
4601                                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4602                                         set_bit(R5_Wantcompute,
4603                                                 &sh->dev[qd_idx].flags);
4604                                         *target = qd_idx;
4605                                         s->uptodate++;
4606                                 }
4607                         }
4608                 }
4609                 break;
4610         case check_state_compute_run:
4611                 break;
4612         default:
4613                 pr_warn("%s: unknown check_state: %d sector: %llu\n",
4614                         __func__, sh->check_state,
4615                         (unsigned long long) sh->sector);
4616                 BUG();
4617         }
4618 }
4619
4620 static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
4621 {
4622         int i;
4623
4624         /* We have read all the blocks in this stripe and now we need to
4625          * copy some of them into a target stripe for expand.
4626          */
4627         struct dma_async_tx_descriptor *tx = NULL;
4628         BUG_ON(sh->batch_head);
4629         clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
4630         for (i = 0; i < sh->disks; i++)
4631                 if (i != sh->pd_idx && i != sh->qd_idx) {
4632                         int dd_idx, j;
4633                         struct stripe_head *sh2;
4634                         struct async_submit_ctl submit;
4635
4636                         sector_t bn = raid5_compute_blocknr(sh, i, 1);
4637                         sector_t s = raid5_compute_sector(conf, bn, 0,
4638                                                           &dd_idx, NULL);
4639                         sh2 = raid5_get_active_stripe(conf, s, 0, 1, 1);
4640                         if (sh2 == NULL)
4641                                 /* so far only the early blocks of this stripe
4642                                  * have been requested.  When later blocks
4643                                  * get requested, we will try again
4644                                  */
4645                                 continue;
4646                         if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
4647                            test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
4648                                 /* must have already done this block */
4649                                 raid5_release_stripe(sh2);
4650                                 continue;
4651                         }
4652
4653                         /* place all the copies on one channel */
4654                         init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
4655                         tx = async_memcpy(sh2->dev[dd_idx].page,
4656                                           sh->dev[i].page, sh2->dev[dd_idx].offset,
4657                                           sh->dev[i].offset, RAID5_STRIPE_SIZE(conf),
4658                                           &submit);
4659
4660                         set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
4661                         set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
4662                         for (j = 0; j < conf->raid_disks; j++)
4663                                 if (j != sh2->pd_idx &&
4664                                     j != sh2->qd_idx &&
4665                                     !test_bit(R5_Expanded, &sh2->dev[j].flags))
4666                                         break;
4667                         if (j == conf->raid_disks) {
4668                                 set_bit(STRIPE_EXPAND_READY, &sh2->state);
4669                                 set_bit(STRIPE_HANDLE, &sh2->state);
4670                         }
4671                         raid5_release_stripe(sh2);
4672
4673                 }
4674         /* done submitting copies, wait for them to complete */
4675         async_tx_quiesce(&tx);
4676 }
4677
4678 /*
4679  * handle_stripe - do things to a stripe.
4680  *
4681  * We lock the stripe by setting STRIPE_ACTIVE and then examine the
4682  * state of various bits to see what needs to be done.
4683  * Possible results:
4684  *    return some read requests which now have data
4685  *    return some write requests which are safely on storage
4686  *    schedule a read on some buffers
4687  *    schedule a write of some buffers
4688  *    return confirmation of parity correctness
4689  *
4690  */
4691
4692 static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
4693 {
4694         struct r5conf *conf = sh->raid_conf;
4695         int disks = sh->disks;
4696         struct r5dev *dev;
4697         int i;
4698         int do_recovery = 0;
4699
4700         memset(s, 0, sizeof(*s));
4701
4702         s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state) && !sh->batch_head;
4703         s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state) && !sh->batch_head;
4704         s->failed_num[0] = -1;
4705         s->failed_num[1] = -1;
4706         s->log_failed = r5l_log_disk_error(conf);
4707
4708         /* Now to look around and see what can be done */
4709         rcu_read_lock();
4710         for (i=disks; i--; ) {
4711                 struct md_rdev *rdev;
4712                 sector_t first_bad;
4713                 int bad_sectors;
4714                 int is_bad = 0;
4715
4716                 dev = &sh->dev[i];
4717
4718                 pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
4719                          i, dev->flags,
4720                          dev->toread, dev->towrite, dev->written);
4721                 /* maybe we can reply to a read
4722                  *
4723                  * new wantfill requests are only permitted while
4724                  * ops_complete_biofill is guaranteed to be inactive
4725                  */
4726                 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
4727                     !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
4728                         set_bit(R5_Wantfill, &dev->flags);
4729
4730                 /* now count some things */
4731                 if (test_bit(R5_LOCKED, &dev->flags))
4732                         s->locked++;
4733                 if (test_bit(R5_UPTODATE, &dev->flags))
4734                         s->uptodate++;
4735                 if (test_bit(R5_Wantcompute, &dev->flags)) {
4736                         s->compute++;
4737                         BUG_ON(s->compute > 2);
4738                 }
4739
4740                 if (test_bit(R5_Wantfill, &dev->flags))
4741                         s->to_fill++;
4742                 else if (dev->toread)
4743                         s->to_read++;
4744                 if (dev->towrite) {
4745                         s->to_write++;
4746                         if (!test_bit(R5_OVERWRITE, &dev->flags))
4747                                 s->non_overwrite++;
4748                 }
4749                 if (dev->written)
4750                         s->written++;
4751                 /* Prefer to use the replacement for reads, but only
4752                  * if it is recovered enough and has no bad blocks.
4753                  */
4754                 rdev = rcu_dereference(conf->disks[i].replacement);
4755                 if (rdev && !test_bit(Faulty, &rdev->flags) &&
4756                     rdev->recovery_offset >= sh->sector + RAID5_STRIPE_SECTORS(conf) &&
4757                     !is_badblock(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf),
4758                                  &first_bad, &bad_sectors))
4759                         set_bit(R5_ReadRepl, &dev->flags);
4760                 else {
4761                         if (rdev && !test_bit(Faulty, &rdev->flags))
4762                                 set_bit(R5_NeedReplace, &dev->flags);
4763                         else
4764                                 clear_bit(R5_NeedReplace, &dev->flags);
4765                         rdev = rcu_dereference(conf->disks[i].rdev);
4766                         clear_bit(R5_ReadRepl, &dev->flags);
4767                 }
4768                 if (rdev && test_bit(Faulty, &rdev->flags))
4769                         rdev = NULL;
4770                 if (rdev) {
4771                         is_bad = is_badblock(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf),
4772                                              &first_bad, &bad_sectors);
4773                         if (s->blocked_rdev == NULL
4774                             && (test_bit(Blocked, &rdev->flags)
4775                                 || is_bad < 0)) {
4776                                 if (is_bad < 0)
4777                                         set_bit(BlockedBadBlocks,
4778                                                 &rdev->flags);
4779                                 s->blocked_rdev = rdev;
4780                                 atomic_inc(&rdev->nr_pending);
4781                         }
4782                 }
4783                 clear_bit(R5_Insync, &dev->flags);
4784                 if (!rdev)
4785                         /* Not in-sync */;
4786                 else if (is_bad) {
4787                         /* also not in-sync */
4788                         if (!test_bit(WriteErrorSeen, &rdev->flags) &&
4789                             test_bit(R5_UPTODATE, &dev->flags)) {
4790                                 /* treat as in-sync, but with a read error
4791                                  * which we can now try to correct
4792                                  */
4793                                 set_bit(R5_Insync, &dev->flags);
4794                                 set_bit(R5_ReadError, &dev->flags);
4795                         }
4796                 } else if (test_bit(In_sync, &rdev->flags))
4797                         set_bit(R5_Insync, &dev->flags);
4798                 else if (sh->sector + RAID5_STRIPE_SECTORS(conf) <= rdev->recovery_offset)
4799                         /* in sync if before recovery_offset */
4800                         set_bit(R5_Insync, &dev->flags);
4801                 else if (test_bit(R5_UPTODATE, &dev->flags) &&
4802                          test_bit(R5_Expanded, &dev->flags))
4803                         /* If we've reshaped into here, we assume it is Insync.
4804                          * We will shortly update recovery_offset to make
4805                          * it official.
4806                          */
4807                         set_bit(R5_Insync, &dev->flags);
4808
4809                 if (test_bit(R5_WriteError, &dev->flags)) {
4810                         /* This flag does not apply to '.replacement'
4811                          * only to .rdev, so make sure to check that*/
4812                         struct md_rdev *rdev2 = rcu_dereference(
4813                                 conf->disks[i].rdev);
4814                         if (rdev2 == rdev)
4815                                 clear_bit(R5_Insync, &dev->flags);
4816                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4817                                 s->handle_bad_blocks = 1;
4818                                 atomic_inc(&rdev2->nr_pending);
4819                         } else
4820                                 clear_bit(R5_WriteError, &dev->flags);
4821                 }
4822                 if (test_bit(R5_MadeGood, &dev->flags)) {
4823                         /* This flag does not apply to '.replacement'
4824                          * only to .rdev, so make sure to check that*/
4825                         struct md_rdev *rdev2 = rcu_dereference(
4826                                 conf->disks[i].rdev);
4827                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4828                                 s->handle_bad_blocks = 1;
4829                                 atomic_inc(&rdev2->nr_pending);
4830                         } else
4831                                 clear_bit(R5_MadeGood, &dev->flags);
4832                 }
4833                 if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
4834                         struct md_rdev *rdev2 = rcu_dereference(
4835                                 conf->disks[i].replacement);
4836                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4837                                 s->handle_bad_blocks = 1;
4838                                 atomic_inc(&rdev2->nr_pending);
4839                         } else
4840                                 clear_bit(R5_MadeGoodRepl, &dev->flags);
4841                 }
4842                 if (!test_bit(R5_Insync, &dev->flags)) {
4843                         /* The ReadError flag will just be confusing now */
4844                         clear_bit(R5_ReadError, &dev->flags);
4845                         clear_bit(R5_ReWrite, &dev->flags);
4846                 }
4847                 if (test_bit(R5_ReadError, &dev->flags))
4848                         clear_bit(R5_Insync, &dev->flags);
4849                 if (!test_bit(R5_Insync, &dev->flags)) {
4850                         if (s->failed < 2)
4851                                 s->failed_num[s->failed] = i;
4852                         s->failed++;
4853                         if (rdev && !test_bit(Faulty, &rdev->flags))
4854                                 do_recovery = 1;
4855                         else if (!rdev) {
4856                                 rdev = rcu_dereference(
4857                                     conf->disks[i].replacement);
4858                                 if (rdev && !test_bit(Faulty, &rdev->flags))
4859                                         do_recovery = 1;
4860                         }
4861                 }
4862
4863                 if (test_bit(R5_InJournal, &dev->flags))
4864                         s->injournal++;
4865                 if (test_bit(R5_InJournal, &dev->flags) && dev->written)
4866                         s->just_cached++;
4867         }
4868         if (test_bit(STRIPE_SYNCING, &sh->state)) {
4869                 /* If there is a failed device being replaced,
4870                  *     we must be recovering.
4871                  * else if we are after recovery_cp, we must be syncing
4872                  * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
4873                  * else we can only be replacing
4874                  * sync and recovery both need to read all devices, and so
4875                  * use the same flag.
4876                  */
4877                 if (do_recovery ||
4878                     sh->sector >= conf->mddev->recovery_cp ||
4879                     test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
4880                         s->syncing = 1;
4881                 else
4882                         s->replacing = 1;
4883         }
4884         rcu_read_unlock();
4885 }
4886
4887 /*
4888  * Return '1' if this is a member of batch, or '0' if it is a lone stripe or
4889  * a head which can now be handled.
4890  */
4891 static int clear_batch_ready(struct stripe_head *sh)
4892 {
4893         struct stripe_head *tmp;
4894         if (!test_and_clear_bit(STRIPE_BATCH_READY, &sh->state))
4895                 return (sh->batch_head && sh->batch_head != sh);
4896         spin_lock(&sh->stripe_lock);
4897         if (!sh->batch_head) {
4898                 spin_unlock(&sh->stripe_lock);
4899                 return 0;
4900         }
4901
4902         /*
4903          * this stripe could be added to a batch list before we check
4904          * BATCH_READY, skips it
4905          */
4906         if (sh->batch_head != sh) {
4907                 spin_unlock(&sh->stripe_lock);
4908                 return 1;
4909         }
4910         spin_lock(&sh->batch_lock);
4911         list_for_each_entry(tmp, &sh->batch_list, batch_list)
4912                 clear_bit(STRIPE_BATCH_READY, &tmp->state);
4913         spin_unlock(&sh->batch_lock);
4914         spin_unlock(&sh->stripe_lock);
4915
4916         /*
4917          * BATCH_READY is cleared, no new stripes can be added.
4918          * batch_list can be accessed without lock
4919          */
4920         return 0;
4921 }
4922
4923 static void break_stripe_batch_list(struct stripe_head *head_sh,
4924                                     unsigned long handle_flags)
4925 {
4926         struct stripe_head *sh, *next;
4927         int i;
4928         int do_wakeup = 0;
4929
4930         list_for_each_entry_safe(sh, next, &head_sh->batch_list, batch_list) {
4931
4932                 list_del_init(&sh->batch_list);
4933
4934                 WARN_ONCE(sh->state & ((1 << STRIPE_ACTIVE) |
4935                                           (1 << STRIPE_SYNCING) |
4936                                           (1 << STRIPE_REPLACED) |
4937                                           (1 << STRIPE_DELAYED) |
4938                                           (1 << STRIPE_BIT_DELAY) |
4939                                           (1 << STRIPE_FULL_WRITE) |
4940                                           (1 << STRIPE_BIOFILL_RUN) |
4941                                           (1 << STRIPE_COMPUTE_RUN)  |
4942                                           (1 << STRIPE_DISCARD) |
4943                                           (1 << STRIPE_BATCH_READY) |
4944                                           (1 << STRIPE_BATCH_ERR) |
4945                                           (1 << STRIPE_BITMAP_PENDING)),
4946                         "stripe state: %lx\n", sh->state);
4947                 WARN_ONCE(head_sh->state & ((1 << STRIPE_DISCARD) |
4948                                               (1 << STRIPE_REPLACED)),
4949                         "head stripe state: %lx\n", head_sh->state);
4950
4951                 set_mask_bits(&sh->state, ~(STRIPE_EXPAND_SYNC_FLAGS |
4952                                             (1 << STRIPE_PREREAD_ACTIVE) |
4953                                             (1 << STRIPE_DEGRADED) |
4954                                             (1 << STRIPE_ON_UNPLUG_LIST)),
4955                               head_sh->state & (1 << STRIPE_INSYNC));
4956
4957                 sh->check_state = head_sh->check_state;
4958                 sh->reconstruct_state = head_sh->reconstruct_state;
4959                 spin_lock_irq(&sh->stripe_lock);
4960                 sh->batch_head = NULL;
4961                 spin_unlock_irq(&sh->stripe_lock);
4962                 for (i = 0; i < sh->disks; i++) {
4963                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
4964                                 do_wakeup = 1;
4965                         sh->dev[i].flags = head_sh->dev[i].flags &
4966                                 (~((1 << R5_WriteError) | (1 << R5_Overlap)));
4967                 }
4968                 if (handle_flags == 0 ||
4969                     sh->state & handle_flags)
4970                         set_bit(STRIPE_HANDLE, &sh->state);
4971                 raid5_release_stripe(sh);
4972         }
4973         spin_lock_irq(&head_sh->stripe_lock);
4974         head_sh->batch_head = NULL;
4975         spin_unlock_irq(&head_sh->stripe_lock);
4976         for (i = 0; i < head_sh->disks; i++)
4977                 if (test_and_clear_bit(R5_Overlap, &head_sh->dev[i].flags))
4978                         do_wakeup = 1;
4979         if (head_sh->state & handle_flags)
4980                 set_bit(STRIPE_HANDLE, &head_sh->state);
4981
4982         if (do_wakeup)
4983                 wake_up(&head_sh->raid_conf->wait_for_overlap);
4984 }
4985
4986 static void handle_stripe(struct stripe_head *sh)
4987 {
4988         struct stripe_head_state s;
4989         struct r5conf *conf = sh->raid_conf;
4990         int i;
4991         int prexor;
4992         int disks = sh->disks;
4993         struct r5dev *pdev, *qdev;
4994
4995         clear_bit(STRIPE_HANDLE, &sh->state);
4996
4997         /*
4998          * handle_stripe should not continue handle the batched stripe, only
4999          * the head of batch list or lone stripe can continue. Otherwise we
5000          * could see break_stripe_batch_list warns about the STRIPE_ACTIVE
5001          * is set for the batched stripe.
5002          */
5003         if (clear_batch_ready(sh))
5004                 return;
5005
5006         if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
5007                 /* already being handled, ensure it gets handled
5008                  * again when current action finishes */
5009                 set_bit(STRIPE_HANDLE, &sh->state);
5010                 return;
5011         }
5012
5013         if (test_and_clear_bit(STRIPE_BATCH_ERR, &sh->state))
5014                 break_stripe_batch_list(sh, 0);
5015
5016         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) && !sh->batch_head) {
5017                 spin_lock(&sh->stripe_lock);
5018                 /*
5019                  * Cannot process 'sync' concurrently with 'discard'.
5020                  * Flush data in r5cache before 'sync'.
5021                  */
5022                 if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) &&
5023                     !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) &&
5024                     !test_bit(STRIPE_DISCARD, &sh->state) &&
5025                     test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
5026                         set_bit(STRIPE_SYNCING, &sh->state);
5027                         clear_bit(STRIPE_INSYNC, &sh->state);
5028                         clear_bit(STRIPE_REPLACED, &sh->state);
5029                 }
5030                 spin_unlock(&sh->stripe_lock);
5031         }
5032         clear_bit(STRIPE_DELAYED, &sh->state);
5033
5034         pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
5035                 "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
5036                (unsigned long long)sh->sector, sh->state,
5037                atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
5038                sh->check_state, sh->reconstruct_state);
5039
5040         analyse_stripe(sh, &s);
5041
5042         if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
5043                 goto finish;
5044
5045         if (s.handle_bad_blocks ||
5046             test_bit(MD_SB_CHANGE_PENDING, &conf->mddev->sb_flags)) {
5047                 set_bit(STRIPE_HANDLE, &sh->state);
5048                 goto finish;
5049         }
5050
5051         if (unlikely(s.blocked_rdev)) {
5052                 if (s.syncing || s.expanding || s.expanded ||
5053                     s.replacing || s.to_write || s.written) {
5054                         set_bit(STRIPE_HANDLE, &sh->state);
5055                         goto finish;
5056                 }
5057                 /* There is nothing for the blocked_rdev to block */
5058                 rdev_dec_pending(s.blocked_rdev, conf->mddev);
5059                 s.blocked_rdev = NULL;
5060         }
5061
5062         if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
5063                 set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
5064                 set_bit(STRIPE_BIOFILL_RUN, &sh->state);
5065         }
5066
5067         pr_debug("locked=%d uptodate=%d to_read=%d"
5068                " to_write=%d failed=%d failed_num=%d,%d\n",
5069                s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
5070                s.failed_num[0], s.failed_num[1]);
5071         /*
5072          * check if the array has lost more than max_degraded devices and,
5073          * if so, some requests might need to be failed.
5074          *
5075          * When journal device failed (log_failed), we will only process
5076          * the stripe if there is data need write to raid disks
5077          */
5078         if (s.failed > conf->max_degraded ||
5079             (s.log_failed && s.injournal == 0)) {
5080                 sh->check_state = 0;
5081                 sh->reconstruct_state = 0;
5082                 break_stripe_batch_list(sh, 0);
5083                 if (s.to_read+s.to_write+s.written)
5084                         handle_failed_stripe(conf, sh, &s, disks);
5085                 if (s.syncing + s.replacing)
5086                         handle_failed_sync(conf, sh, &s);
5087         }
5088
5089         /* Now we check to see if any write operations have recently
5090          * completed
5091          */
5092         prexor = 0;
5093         if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
5094                 prexor = 1;
5095         if (sh->reconstruct_state == reconstruct_state_drain_result ||
5096             sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
5097                 sh->reconstruct_state = reconstruct_state_idle;
5098
5099                 /* All the 'written' buffers and the parity block are ready to
5100                  * be written back to disk
5101                  */
5102                 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
5103                        !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
5104                 BUG_ON(sh->qd_idx >= 0 &&
5105                        !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
5106                        !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
5107                 for (i = disks; i--; ) {
5108                         struct r5dev *dev = &sh->dev[i];
5109                         if (test_bit(R5_LOCKED, &dev->flags) &&
5110                                 (i == sh->pd_idx || i == sh->qd_idx ||
5111                                  dev->written || test_bit(R5_InJournal,
5112                                                           &dev->flags))) {
5113                                 pr_debug("Writing block %d\n", i);
5114                                 set_bit(R5_Wantwrite, &dev->flags);
5115                                 if (prexor)
5116                                         continue;
5117                                 if (s.failed > 1)
5118                                         continue;
5119                                 if (!test_bit(R5_Insync, &dev->flags) ||
5120                                     ((i == sh->pd_idx || i == sh->qd_idx)  &&
5121                                      s.failed == 0))
5122                                         set_bit(STRIPE_INSYNC, &sh->state);
5123                         }
5124                 }
5125                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5126                         s.dec_preread_active = 1;
5127         }
5128
5129         /*
5130          * might be able to return some write requests if the parity blocks
5131          * are safe, or on a failed drive
5132          */
5133         pdev = &sh->dev[sh->pd_idx];
5134         s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
5135                 || (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
5136         qdev = &sh->dev[sh->qd_idx];
5137         s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
5138                 || (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
5139                 || conf->level < 6;
5140
5141         if (s.written &&
5142             (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
5143                              && !test_bit(R5_LOCKED, &pdev->flags)
5144                              && (test_bit(R5_UPTODATE, &pdev->flags) ||
5145                                  test_bit(R5_Discard, &pdev->flags))))) &&
5146             (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
5147                              && !test_bit(R5_LOCKED, &qdev->flags)
5148                              && (test_bit(R5_UPTODATE, &qdev->flags) ||
5149                                  test_bit(R5_Discard, &qdev->flags))))))
5150                 handle_stripe_clean_event(conf, sh, disks);
5151
5152         if (s.just_cached)
5153                 r5c_handle_cached_data_endio(conf, sh, disks);
5154         log_stripe_write_finished(sh);
5155
5156         /* Now we might consider reading some blocks, either to check/generate
5157          * parity, or to satisfy requests
5158          * or to load a block that is being partially written.
5159          */
5160         if (s.to_read || s.non_overwrite
5161             || (s.to_write && s.failed)
5162             || (s.syncing && (s.uptodate + s.compute < disks))
5163             || s.replacing
5164             || s.expanding)
5165                 handle_stripe_fill(sh, &s, disks);
5166
5167         /*
5168          * When the stripe finishes full journal write cycle (write to journal
5169          * and raid disk), this is the clean up procedure so it is ready for
5170          * next operation.
5171          */
5172         r5c_finish_stripe_write_out(conf, sh, &s);
5173
5174         /*
5175          * Now to consider new write requests, cache write back and what else,
5176          * if anything should be read.  We do not handle new writes when:
5177          * 1/ A 'write' operation (copy+xor) is already in flight.
5178          * 2/ A 'check' operation is in flight, as it may clobber the parity
5179          *    block.
5180          * 3/ A r5c cache log write is in flight.
5181          */
5182
5183         if (!sh->reconstruct_state && !sh->check_state && !sh->log_io) {
5184                 if (!r5c_is_writeback(conf->log)) {
5185                         if (s.to_write)
5186                                 handle_stripe_dirtying(conf, sh, &s, disks);
5187                 } else { /* write back cache */
5188                         int ret = 0;
5189
5190                         /* First, try handle writes in caching phase */
5191                         if (s.to_write)
5192                                 ret = r5c_try_caching_write(conf, sh, &s,
5193                                                             disks);
5194                         /*
5195                          * If caching phase failed: ret == -EAGAIN
5196                          *    OR
5197                          * stripe under reclaim: !caching && injournal
5198                          *
5199                          * fall back to handle_stripe_dirtying()
5200                          */
5201                         if (ret == -EAGAIN ||
5202                             /* stripe under reclaim: !caching && injournal */
5203                             (!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
5204                              s.injournal > 0)) {
5205                                 ret = handle_stripe_dirtying(conf, sh, &s,
5206                                                              disks);
5207                                 if (ret == -EAGAIN)
5208                                         goto finish;
5209                         }
5210                 }
5211         }
5212
5213         /* maybe we need to check and possibly fix the parity for this stripe
5214          * Any reads will already have been scheduled, so we just see if enough
5215          * data is available.  The parity check is held off while parity
5216          * dependent operations are in flight.
5217          */
5218         if (sh->check_state ||
5219             (s.syncing && s.locked == 0 &&
5220              !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
5221              !test_bit(STRIPE_INSYNC, &sh->state))) {
5222                 if (conf->level == 6)
5223                         handle_parity_checks6(conf, sh, &s, disks);
5224                 else
5225                         handle_parity_checks5(conf, sh, &s, disks);
5226         }
5227
5228         if ((s.replacing || s.syncing) && s.locked == 0
5229             && !test_bit(STRIPE_COMPUTE_RUN, &sh->state)
5230             && !test_bit(STRIPE_REPLACED, &sh->state)) {
5231                 /* Write out to replacement devices where possible */
5232                 for (i = 0; i < conf->raid_disks; i++)
5233                         if (test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
5234                                 WARN_ON(!test_bit(R5_UPTODATE, &sh->dev[i].flags));
5235                                 set_bit(R5_WantReplace, &sh->dev[i].flags);
5236                                 set_bit(R5_LOCKED, &sh->dev[i].flags);
5237                                 s.locked++;
5238                         }
5239                 if (s.replacing)
5240                         set_bit(STRIPE_INSYNC, &sh->state);
5241                 set_bit(STRIPE_REPLACED, &sh->state);
5242         }
5243         if ((s.syncing || s.replacing) && s.locked == 0 &&
5244             !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
5245             test_bit(STRIPE_INSYNC, &sh->state)) {
5246                 md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), 1);
5247                 clear_bit(STRIPE_SYNCING, &sh->state);
5248                 if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
5249                         wake_up(&conf->wait_for_overlap);
5250         }
5251
5252         /* If the failed drives are just a ReadError, then we might need
5253          * to progress the repair/check process
5254          */
5255         if (s.failed <= conf->max_degraded && !conf->mddev->ro)
5256                 for (i = 0; i < s.failed; i++) {
5257                         struct r5dev *dev = &sh->dev[s.failed_num[i]];
5258                         if (test_bit(R5_ReadError, &dev->flags)
5259                             && !test_bit(R5_LOCKED, &dev->flags)
5260                             && test_bit(R5_UPTODATE, &dev->flags)
5261                                 ) {
5262                                 if (!test_bit(R5_ReWrite, &dev->flags)) {
5263                                         set_bit(R5_Wantwrite, &dev->flags);
5264                                         set_bit(R5_ReWrite, &dev->flags);
5265                                 } else
5266                                         /* let's read it back */
5267                                         set_bit(R5_Wantread, &dev->flags);
5268                                 set_bit(R5_LOCKED, &dev->flags);
5269                                 s.locked++;
5270                         }
5271                 }
5272
5273         /* Finish reconstruct operations initiated by the expansion process */
5274         if (sh->reconstruct_state == reconstruct_state_result) {
5275                 struct stripe_head *sh_src
5276                         = raid5_get_active_stripe(conf, sh->sector, 1, 1, 1);
5277                 if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
5278                         /* sh cannot be written until sh_src has been read.
5279                          * so arrange for sh to be delayed a little
5280                          */
5281                         set_bit(STRIPE_DELAYED, &sh->state);
5282                         set_bit(STRIPE_HANDLE, &sh->state);
5283                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
5284                                               &sh_src->state))
5285                                 atomic_inc(&conf->preread_active_stripes);
5286                         raid5_release_stripe(sh_src);
5287                         goto finish;
5288                 }
5289                 if (sh_src)
5290                         raid5_release_stripe(sh_src);
5291
5292                 sh->reconstruct_state = reconstruct_state_idle;
5293                 clear_bit(STRIPE_EXPANDING, &sh->state);
5294                 for (i = conf->raid_disks; i--; ) {
5295                         set_bit(R5_Wantwrite, &sh->dev[i].flags);
5296                         set_bit(R5_LOCKED, &sh->dev[i].flags);
5297                         s.locked++;
5298                 }
5299         }
5300
5301         if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
5302             !sh->reconstruct_state) {
5303                 /* Need to write out all blocks after computing parity */
5304                 sh->disks = conf->raid_disks;
5305                 stripe_set_idx(sh->sector, conf, 0, sh);
5306                 schedule_reconstruction(sh, &s, 1, 1);
5307         } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
5308                 clear_bit(STRIPE_EXPAND_READY, &sh->state);
5309                 atomic_dec(&conf->reshape_stripes);
5310                 wake_up(&conf->wait_for_overlap);
5311                 md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), 1);
5312         }
5313
5314         if (s.expanding && s.locked == 0 &&
5315             !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
5316                 handle_stripe_expansion(conf, sh);
5317
5318 finish:
5319         /* wait for this device to become unblocked */
5320         if (unlikely(s.blocked_rdev)) {
5321                 if (conf->mddev->external)
5322                         md_wait_for_blocked_rdev(s.blocked_rdev,
5323                                                  conf->mddev);
5324                 else
5325                         /* Internal metadata will immediately
5326                          * be written by raid5d, so we don't
5327                          * need to wait here.
5328                          */
5329                         rdev_dec_pending(s.blocked_rdev,
5330                                          conf->mddev);
5331         }
5332
5333         if (s.handle_bad_blocks)
5334                 for (i = disks; i--; ) {
5335                         struct md_rdev *rdev;
5336                         struct r5dev *dev = &sh->dev[i];
5337                         if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
5338                                 /* We own a safe reference to the rdev */
5339                                 rdev = rdev_pend_deref(conf->disks[i].rdev);
5340                                 if (!rdev_set_badblocks(rdev, sh->sector,
5341                                                         RAID5_STRIPE_SECTORS(conf), 0))
5342                                         md_error(conf->mddev, rdev);
5343                                 rdev_dec_pending(rdev, conf->mddev);
5344                         }
5345                         if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
5346                                 rdev = rdev_pend_deref(conf->disks[i].rdev);
5347                                 rdev_clear_badblocks(rdev, sh->sector,
5348                                                      RAID5_STRIPE_SECTORS(conf), 0);
5349                                 rdev_dec_pending(rdev, conf->mddev);
5350                         }
5351                         if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
5352                                 rdev = rdev_pend_deref(conf->disks[i].replacement);
5353                                 if (!rdev)
5354                                         /* rdev have been moved down */
5355                                         rdev = rdev_pend_deref(conf->disks[i].rdev);
5356                                 rdev_clear_badblocks(rdev, sh->sector,
5357                                                      RAID5_STRIPE_SECTORS(conf), 0);
5358                                 rdev_dec_pending(rdev, conf->mddev);
5359                         }
5360                 }
5361
5362         if (s.ops_request)
5363                 raid_run_ops(sh, s.ops_request);
5364
5365         ops_run_io(sh, &s);
5366
5367         if (s.dec_preread_active) {
5368                 /* We delay this until after ops_run_io so that if make_request
5369                  * is waiting on a flush, it won't continue until the writes
5370                  * have actually been submitted.
5371                  */
5372                 atomic_dec(&conf->preread_active_stripes);
5373                 if (atomic_read(&conf->preread_active_stripes) <
5374                     IO_THRESHOLD)
5375                         md_wakeup_thread(conf->mddev->thread);
5376         }
5377
5378         clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
5379 }
5380
5381 static void raid5_activate_delayed(struct r5conf *conf)
5382         __must_hold(&conf->device_lock)
5383 {
5384         if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
5385                 while (!list_empty(&conf->delayed_list)) {
5386                         struct list_head *l = conf->delayed_list.next;
5387                         struct stripe_head *sh;
5388                         sh = list_entry(l, struct stripe_head, lru);
5389                         list_del_init(l);
5390                         clear_bit(STRIPE_DELAYED, &sh->state);
5391                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5392                                 atomic_inc(&conf->preread_active_stripes);
5393                         list_add_tail(&sh->lru, &conf->hold_list);
5394                         raid5_wakeup_stripe_thread(sh);
5395                 }
5396         }
5397 }
5398
5399 static void activate_bit_delay(struct r5conf *conf,
5400                 struct list_head *temp_inactive_list)
5401         __must_hold(&conf->device_lock)
5402 {
5403         struct list_head head;
5404         list_add(&head, &conf->bitmap_list);
5405         list_del_init(&conf->bitmap_list);
5406         while (!list_empty(&head)) {
5407                 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
5408                 int hash;
5409                 list_del_init(&sh->lru);
5410                 atomic_inc(&sh->count);
5411                 hash = sh->hash_lock_index;
5412                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
5413         }
5414 }
5415
5416 static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
5417 {
5418         struct r5conf *conf = mddev->private;
5419         sector_t sector = bio->bi_iter.bi_sector;
5420         unsigned int chunk_sectors;
5421         unsigned int bio_sectors = bio_sectors(bio);
5422
5423         chunk_sectors = min(conf->chunk_sectors, conf->prev_chunk_sectors);
5424         return  chunk_sectors >=
5425                 ((sector & (chunk_sectors - 1)) + bio_sectors);
5426 }
5427
5428 /*
5429  *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
5430  *  later sampled by raid5d.
5431  */
5432 static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
5433 {
5434         unsigned long flags;
5435
5436         spin_lock_irqsave(&conf->device_lock, flags);
5437
5438         bi->bi_next = conf->retry_read_aligned_list;
5439         conf->retry_read_aligned_list = bi;
5440
5441         spin_unlock_irqrestore(&conf->device_lock, flags);
5442         md_wakeup_thread(conf->mddev->thread);
5443 }
5444
5445 static struct bio *remove_bio_from_retry(struct r5conf *conf,
5446                                          unsigned int *offset)
5447 {
5448         struct bio *bi;
5449
5450         bi = conf->retry_read_aligned;
5451         if (bi) {
5452                 *offset = conf->retry_read_offset;
5453                 conf->retry_read_aligned = NULL;
5454                 return bi;
5455         }
5456         bi = conf->retry_read_aligned_list;
5457         if(bi) {
5458                 conf->retry_read_aligned_list = bi->bi_next;
5459                 bi->bi_next = NULL;
5460                 *offset = 0;
5461         }
5462
5463         return bi;
5464 }
5465
5466 /*
5467  *  The "raid5_align_endio" should check if the read succeeded and if it
5468  *  did, call bio_endio on the original bio (having bio_put the new bio
5469  *  first).
5470  *  If the read failed..
5471  */
5472 static void raid5_align_endio(struct bio *bi)
5473 {
5474         struct md_io_acct *md_io_acct = bi->bi_private;
5475         struct bio *raid_bi = md_io_acct->orig_bio;
5476         struct mddev *mddev;
5477         struct r5conf *conf;
5478         struct md_rdev *rdev;
5479         blk_status_t error = bi->bi_status;
5480         unsigned long start_time = md_io_acct->start_time;
5481
5482         bio_put(bi);
5483
5484         rdev = (void*)raid_bi->bi_next;
5485         raid_bi->bi_next = NULL;
5486         mddev = rdev->mddev;
5487         conf = mddev->private;
5488
5489         rdev_dec_pending(rdev, conf->mddev);
5490
5491         if (!error) {
5492                 if (blk_queue_io_stat(raid_bi->bi_bdev->bd_disk->queue))
5493                         bio_end_io_acct(raid_bi, start_time);
5494                 bio_endio(raid_bi);
5495                 if (atomic_dec_and_test(&conf->active_aligned_reads))
5496                         wake_up(&conf->wait_for_quiescent);
5497                 return;
5498         }
5499
5500         pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
5501
5502         add_bio_to_retry(raid_bi, conf);
5503 }
5504
5505 static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
5506 {
5507         struct r5conf *conf = mddev->private;
5508         struct bio *align_bio;
5509         struct md_rdev *rdev;
5510         sector_t sector, end_sector, first_bad;
5511         int bad_sectors, dd_idx;
5512         struct md_io_acct *md_io_acct;
5513         bool did_inc;
5514
5515         if (!in_chunk_boundary(mddev, raid_bio)) {
5516                 pr_debug("%s: non aligned\n", __func__);
5517                 return 0;
5518         }
5519
5520         sector = raid5_compute_sector(conf, raid_bio->bi_iter.bi_sector, 0,
5521                                       &dd_idx, NULL);
5522         end_sector = bio_end_sector(raid_bio);
5523
5524         rcu_read_lock();
5525         if (r5c_big_stripe_cached(conf, sector))
5526                 goto out_rcu_unlock;
5527
5528         rdev = rcu_dereference(conf->disks[dd_idx].replacement);
5529         if (!rdev || test_bit(Faulty, &rdev->flags) ||
5530             rdev->recovery_offset < end_sector) {
5531                 rdev = rcu_dereference(conf->disks[dd_idx].rdev);
5532                 if (!rdev)
5533                         goto out_rcu_unlock;
5534                 if (test_bit(Faulty, &rdev->flags) ||
5535                     !(test_bit(In_sync, &rdev->flags) ||
5536                       rdev->recovery_offset >= end_sector))
5537                         goto out_rcu_unlock;
5538         }
5539
5540         atomic_inc(&rdev->nr_pending);
5541         rcu_read_unlock();
5542
5543         if (is_badblock(rdev, sector, bio_sectors(raid_bio), &first_bad,
5544                         &bad_sectors)) {
5545                 bio_put(raid_bio);
5546                 rdev_dec_pending(rdev, mddev);
5547                 return 0;
5548         }
5549
5550         align_bio = bio_alloc_clone(rdev->bdev, raid_bio, GFP_NOIO,
5551                                     &mddev->io_acct_set);
5552         md_io_acct = container_of(align_bio, struct md_io_acct, bio_clone);
5553         raid_bio->bi_next = (void *)rdev;
5554         if (blk_queue_io_stat(raid_bio->bi_bdev->bd_disk->queue))
5555                 md_io_acct->start_time = bio_start_io_acct(raid_bio);
5556         md_io_acct->orig_bio = raid_bio;
5557
5558         align_bio->bi_end_io = raid5_align_endio;
5559         align_bio->bi_private = md_io_acct;
5560         align_bio->bi_iter.bi_sector = sector;
5561
5562         /* No reshape active, so we can trust rdev->data_offset */
5563         align_bio->bi_iter.bi_sector += rdev->data_offset;
5564
5565         did_inc = false;
5566         if (conf->quiesce == 0) {
5567                 atomic_inc(&conf->active_aligned_reads);
5568                 did_inc = true;
5569         }
5570         /* need a memory barrier to detect the race with raid5_quiesce() */
5571         if (!did_inc || smp_load_acquire(&conf->quiesce) != 0) {
5572                 /* quiesce is in progress, so we need to undo io activation and wait
5573                  * for it to finish
5574                  */
5575                 if (did_inc && atomic_dec_and_test(&conf->active_aligned_reads))
5576                         wake_up(&conf->wait_for_quiescent);
5577                 spin_lock_irq(&conf->device_lock);
5578                 wait_event_lock_irq(conf->wait_for_quiescent, conf->quiesce == 0,
5579                                     conf->device_lock);
5580                 atomic_inc(&conf->active_aligned_reads);
5581                 spin_unlock_irq(&conf->device_lock);
5582         }
5583
5584         if (mddev->gendisk)
5585                 trace_block_bio_remap(align_bio, disk_devt(mddev->gendisk),
5586                                       raid_bio->bi_iter.bi_sector);
5587         submit_bio_noacct(align_bio);
5588         return 1;
5589
5590 out_rcu_unlock:
5591         rcu_read_unlock();
5592         return 0;
5593 }
5594
5595 static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
5596 {
5597         struct bio *split;
5598         sector_t sector = raid_bio->bi_iter.bi_sector;
5599         unsigned chunk_sects = mddev->chunk_sectors;
5600         unsigned sectors = chunk_sects - (sector & (chunk_sects-1));
5601
5602         if (sectors < bio_sectors(raid_bio)) {
5603                 struct r5conf *conf = mddev->private;
5604                 split = bio_split(raid_bio, sectors, GFP_NOIO, &conf->bio_split);
5605                 bio_chain(split, raid_bio);
5606                 submit_bio_noacct(raid_bio);
5607                 raid_bio = split;
5608         }
5609
5610         if (!raid5_read_one_chunk(mddev, raid_bio))
5611                 return raid_bio;
5612
5613         return NULL;
5614 }
5615
5616 /* __get_priority_stripe - get the next stripe to process
5617  *
5618  * Full stripe writes are allowed to pass preread active stripes up until
5619  * the bypass_threshold is exceeded.  In general the bypass_count
5620  * increments when the handle_list is handled before the hold_list; however, it
5621  * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
5622  * stripe with in flight i/o.  The bypass_count will be reset when the
5623  * head of the hold_list has changed, i.e. the head was promoted to the
5624  * handle_list.
5625  */
5626 static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group)
5627         __must_hold(&conf->device_lock)
5628 {
5629         struct stripe_head *sh, *tmp;
5630         struct list_head *handle_list = NULL;
5631         struct r5worker_group *wg;
5632         bool second_try = !r5c_is_writeback(conf->log) &&
5633                 !r5l_log_disk_error(conf);
5634         bool try_loprio = test_bit(R5C_LOG_TIGHT, &conf->cache_state) ||
5635                 r5l_log_disk_error(conf);
5636
5637 again:
5638         wg = NULL;
5639         sh = NULL;
5640         if (conf->worker_cnt_per_group == 0) {
5641                 handle_list = try_loprio ? &conf->loprio_list :
5642                                         &conf->handle_list;
5643         } else if (group != ANY_GROUP) {
5644                 handle_list = try_loprio ? &conf->worker_groups[group].loprio_list :
5645                                 &conf->worker_groups[group].handle_list;
5646                 wg = &conf->worker_groups[group];
5647         } else {
5648                 int i;
5649                 for (i = 0; i < conf->group_cnt; i++) {
5650                         handle_list = try_loprio ? &conf->worker_groups[i].loprio_list :
5651                                 &conf->worker_groups[i].handle_list;
5652                         wg = &conf->worker_groups[i];
5653                         if (!list_empty(handle_list))
5654                                 break;
5655                 }
5656         }
5657
5658         pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
5659                   __func__,
5660                   list_empty(handle_list) ? "empty" : "busy",
5661                   list_empty(&conf->hold_list) ? "empty" : "busy",
5662                   atomic_read(&conf->pending_full_writes), conf->bypass_count);
5663
5664         if (!list_empty(handle_list)) {
5665                 sh = list_entry(handle_list->next, typeof(*sh), lru);
5666
5667                 if (list_empty(&conf->hold_list))
5668                         conf->bypass_count = 0;
5669                 else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
5670                         if (conf->hold_list.next == conf->last_hold)
5671                                 conf->bypass_count++;
5672                         else {
5673                                 conf->last_hold = conf->hold_list.next;
5674                                 conf->bypass_count -= conf->bypass_threshold;
5675                                 if (conf->bypass_count < 0)
5676                                         conf->bypass_count = 0;
5677                         }
5678                 }
5679         } else if (!list_empty(&conf->hold_list) &&
5680                    ((conf->bypass_threshold &&
5681                      conf->bypass_count > conf->bypass_threshold) ||
5682                     atomic_read(&conf->pending_full_writes) == 0)) {
5683
5684                 list_for_each_entry(tmp, &conf->hold_list,  lru) {
5685                         if (conf->worker_cnt_per_group == 0 ||
5686                             group == ANY_GROUP ||
5687                             !cpu_online(tmp->cpu) ||
5688                             cpu_to_group(tmp->cpu) == group) {
5689                                 sh = tmp;
5690                                 break;
5691                         }
5692                 }
5693
5694                 if (sh) {
5695                         conf->bypass_count -= conf->bypass_threshold;
5696                         if (conf->bypass_count < 0)
5697                                 conf->bypass_count = 0;
5698                 }
5699                 wg = NULL;
5700         }
5701
5702         if (!sh) {
5703                 if (second_try)
5704                         return NULL;
5705                 second_try = true;
5706                 try_loprio = !try_loprio;
5707                 goto again;
5708         }
5709
5710         if (wg) {
5711                 wg->stripes_cnt--;
5712                 sh->group = NULL;
5713         }
5714         list_del_init(&sh->lru);
5715         BUG_ON(atomic_inc_return(&sh->count) != 1);
5716         return sh;
5717 }
5718
5719 struct raid5_plug_cb {
5720         struct blk_plug_cb      cb;
5721         struct list_head        list;
5722         struct list_head        temp_inactive_list[NR_STRIPE_HASH_LOCKS];
5723 };
5724
5725 static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
5726 {
5727         struct raid5_plug_cb *cb = container_of(
5728                 blk_cb, struct raid5_plug_cb, cb);
5729         struct stripe_head *sh;
5730         struct mddev *mddev = cb->cb.data;
5731         struct r5conf *conf = mddev->private;
5732         int cnt = 0;
5733         int hash;
5734
5735         if (cb->list.next && !list_empty(&cb->list)) {
5736                 spin_lock_irq(&conf->device_lock);
5737                 while (!list_empty(&cb->list)) {
5738                         sh = list_first_entry(&cb->list, struct stripe_head, lru);
5739                         list_del_init(&sh->lru);
5740                         /*
5741                          * avoid race release_stripe_plug() sees
5742                          * STRIPE_ON_UNPLUG_LIST clear but the stripe
5743                          * is still in our list
5744                          */
5745                         smp_mb__before_atomic();
5746                         clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
5747                         /*
5748                          * STRIPE_ON_RELEASE_LIST could be set here. In that
5749                          * case, the count is always > 1 here
5750                          */
5751                         hash = sh->hash_lock_index;
5752                         __release_stripe(conf, sh, &cb->temp_inactive_list[hash]);
5753                         cnt++;
5754                 }
5755                 spin_unlock_irq(&conf->device_lock);
5756         }
5757         release_inactive_stripe_list(conf, cb->temp_inactive_list,
5758                                      NR_STRIPE_HASH_LOCKS);
5759         if (mddev->queue)
5760                 trace_block_unplug(mddev->queue, cnt, !from_schedule);
5761         kfree(cb);
5762 }
5763
5764 static void release_stripe_plug(struct mddev *mddev,
5765                                 struct stripe_head *sh)
5766 {
5767         struct blk_plug_cb *blk_cb = blk_check_plugged(
5768                 raid5_unplug, mddev,
5769                 sizeof(struct raid5_plug_cb));
5770         struct raid5_plug_cb *cb;
5771
5772         if (!blk_cb) {
5773                 raid5_release_stripe(sh);
5774                 return;
5775         }
5776
5777         cb = container_of(blk_cb, struct raid5_plug_cb, cb);
5778
5779         if (cb->list.next == NULL) {
5780                 int i;
5781                 INIT_LIST_HEAD(&cb->list);
5782                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
5783                         INIT_LIST_HEAD(cb->temp_inactive_list + i);
5784         }
5785
5786         if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
5787                 list_add_tail(&sh->lru, &cb->list);
5788         else
5789                 raid5_release_stripe(sh);
5790 }
5791
5792 static void make_discard_request(struct mddev *mddev, struct bio *bi)
5793 {
5794         struct r5conf *conf = mddev->private;
5795         sector_t logical_sector, last_sector;
5796         struct stripe_head *sh;
5797         int stripe_sectors;
5798
5799         /* We need to handle this when io_uring supports discard/trim */
5800         if (WARN_ON_ONCE(bi->bi_opf & REQ_NOWAIT))
5801                 return;
5802
5803         if (mddev->reshape_position != MaxSector)
5804                 /* Skip discard while reshape is happening */
5805                 return;
5806
5807         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
5808         last_sector = bio_end_sector(bi);
5809
5810         bi->bi_next = NULL;
5811
5812         stripe_sectors = conf->chunk_sectors *
5813                 (conf->raid_disks - conf->max_degraded);
5814         logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
5815                                                stripe_sectors);
5816         sector_div(last_sector, stripe_sectors);
5817
5818         logical_sector *= conf->chunk_sectors;
5819         last_sector *= conf->chunk_sectors;
5820
5821         for (; logical_sector < last_sector;
5822              logical_sector += RAID5_STRIPE_SECTORS(conf)) {
5823                 DEFINE_WAIT(w);
5824                 int d;
5825         again:
5826                 sh = raid5_get_active_stripe(conf, logical_sector, 0, 0, 0);
5827                 prepare_to_wait(&conf->wait_for_overlap, &w,
5828                                 TASK_UNINTERRUPTIBLE);
5829                 set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5830                 if (test_bit(STRIPE_SYNCING, &sh->state)) {
5831                         raid5_release_stripe(sh);
5832                         schedule();
5833                         goto again;
5834                 }
5835                 clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5836                 spin_lock_irq(&sh->stripe_lock);
5837                 for (d = 0; d < conf->raid_disks; d++) {
5838                         if (d == sh->pd_idx || d == sh->qd_idx)
5839                                 continue;
5840                         if (sh->dev[d].towrite || sh->dev[d].toread) {
5841                                 set_bit(R5_Overlap, &sh->dev[d].flags);
5842                                 spin_unlock_irq(&sh->stripe_lock);
5843                                 raid5_release_stripe(sh);
5844                                 schedule();
5845                                 goto again;
5846                         }
5847                 }
5848                 set_bit(STRIPE_DISCARD, &sh->state);
5849                 finish_wait(&conf->wait_for_overlap, &w);
5850                 sh->overwrite_disks = 0;
5851                 for (d = 0; d < conf->raid_disks; d++) {
5852                         if (d == sh->pd_idx || d == sh->qd_idx)
5853                                 continue;
5854                         sh->dev[d].towrite = bi;
5855                         set_bit(R5_OVERWRITE, &sh->dev[d].flags);
5856                         bio_inc_remaining(bi);
5857                         md_write_inc(mddev, bi);
5858                         sh->overwrite_disks++;
5859                 }
5860                 spin_unlock_irq(&sh->stripe_lock);
5861                 if (conf->mddev->bitmap) {
5862                         for (d = 0;
5863                              d < conf->raid_disks - conf->max_degraded;
5864                              d++)
5865                                 md_bitmap_startwrite(mddev->bitmap,
5866                                                      sh->sector,
5867                                                      RAID5_STRIPE_SECTORS(conf),
5868                                                      0);
5869                         sh->bm_seq = conf->seq_flush + 1;
5870                         set_bit(STRIPE_BIT_DELAY, &sh->state);
5871                 }
5872
5873                 set_bit(STRIPE_HANDLE, &sh->state);
5874                 clear_bit(STRIPE_DELAYED, &sh->state);
5875                 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5876                         atomic_inc(&conf->preread_active_stripes);
5877                 release_stripe_plug(mddev, sh);
5878         }
5879
5880         bio_endio(bi);
5881 }
5882
5883 static bool ahead_of_reshape(struct mddev *mddev, sector_t sector,
5884                              sector_t reshape_sector)
5885 {
5886         return mddev->reshape_backwards ? sector < reshape_sector :
5887                                           sector >= reshape_sector;
5888 }
5889
5890 static bool range_ahead_of_reshape(struct mddev *mddev, sector_t min,
5891                                    sector_t max, sector_t reshape_sector)
5892 {
5893         return mddev->reshape_backwards ? max < reshape_sector :
5894                                           min >= reshape_sector;
5895 }
5896
5897 static bool stripe_ahead_of_reshape(struct mddev *mddev, struct r5conf *conf,
5898                                     struct stripe_head *sh)
5899 {
5900         sector_t max_sector = 0, min_sector = MaxSector;
5901         bool ret = false;
5902         int dd_idx;
5903
5904         for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) {
5905                 if (dd_idx == sh->pd_idx)
5906                         continue;
5907
5908                 min_sector = min(min_sector, sh->dev[dd_idx].sector);
5909                 max_sector = min(max_sector, sh->dev[dd_idx].sector);
5910         }
5911
5912         spin_lock_irq(&conf->device_lock);
5913
5914         if (!range_ahead_of_reshape(mddev, min_sector, max_sector,
5915                                      conf->reshape_progress))
5916                 /* mismatch, need to try again */
5917                 ret = true;
5918
5919         spin_unlock_irq(&conf->device_lock);
5920
5921         return ret;
5922 }
5923
5924 static int add_all_stripe_bios(struct r5conf *conf,
5925                 struct stripe_request_ctx *ctx, struct stripe_head *sh,
5926                 struct bio *bi, int forwrite, int previous)
5927 {
5928         int dd_idx;
5929         int ret = 1;
5930
5931         spin_lock_irq(&sh->stripe_lock);
5932
5933         for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) {
5934                 struct r5dev *dev = &sh->dev[dd_idx];
5935
5936                 if (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
5937                         continue;
5938
5939                 if (dev->sector < ctx->first_sector ||
5940                     dev->sector >= ctx->last_sector)
5941                         continue;
5942
5943                 if (stripe_bio_overlaps(sh, bi, dd_idx, forwrite)) {
5944                         set_bit(R5_Overlap, &dev->flags);
5945                         ret = 0;
5946                         continue;
5947                 }
5948         }
5949
5950         if (!ret)
5951                 goto out;
5952
5953         for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) {
5954                 struct r5dev *dev = &sh->dev[dd_idx];
5955
5956                 if (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
5957                         continue;
5958
5959                 if (dev->sector < ctx->first_sector ||
5960                     dev->sector >= ctx->last_sector)
5961                         continue;
5962
5963                 __add_stripe_bio(sh, bi, dd_idx, forwrite, previous);
5964                 clear_bit((dev->sector - ctx->first_sector) >>
5965                           RAID5_STRIPE_SHIFT(conf), ctx->sectors_to_do);
5966         }
5967
5968 out:
5969         spin_unlock_irq(&sh->stripe_lock);
5970         return ret;
5971 }
5972
5973 static enum stripe_result make_stripe_request(struct mddev *mddev,
5974                 struct r5conf *conf, struct stripe_request_ctx *ctx,
5975                 sector_t logical_sector, struct bio *bi)
5976 {
5977         const int rw = bio_data_dir(bi);
5978         enum stripe_result ret;
5979         struct stripe_head *sh;
5980         sector_t new_sector;
5981         int previous = 0;
5982         int seq, dd_idx;
5983
5984         seq = read_seqcount_begin(&conf->gen_lock);
5985
5986         if (unlikely(conf->reshape_progress != MaxSector)) {
5987                 /*
5988                  * Spinlock is needed as reshape_progress may be
5989                  * 64bit on a 32bit platform, and so it might be
5990                  * possible to see a half-updated value
5991                  * Of course reshape_progress could change after
5992                  * the lock is dropped, so once we get a reference
5993                  * to the stripe that we think it is, we will have
5994                  * to check again.
5995                  */
5996                 spin_lock_irq(&conf->device_lock);
5997                 if (ahead_of_reshape(mddev, logical_sector,
5998                                      conf->reshape_progress)) {
5999                         previous = 1;
6000                 } else {
6001                         if (ahead_of_reshape(mddev, logical_sector,
6002                                              conf->reshape_safe)) {
6003                                 spin_unlock_irq(&conf->device_lock);
6004                                 return STRIPE_SCHEDULE_AND_RETRY;
6005                         }
6006                 }
6007                 spin_unlock_irq(&conf->device_lock);
6008         }
6009
6010         new_sector = raid5_compute_sector(conf, logical_sector, previous,
6011                                           &dd_idx, NULL);
6012         pr_debug("raid456: %s, sector %llu logical %llu\n", __func__,
6013                  new_sector, logical_sector);
6014
6015         sh = __raid5_get_active_stripe(conf, ctx, new_sector, previous,
6016                                        (bi->bi_opf & REQ_RAHEAD), 0);
6017         if (unlikely(!sh)) {
6018                 /* cannot get stripe, just give-up */
6019                 bi->bi_status = BLK_STS_IOERR;
6020                 return STRIPE_FAIL;
6021         }
6022
6023         if (unlikely(previous) &&
6024             stripe_ahead_of_reshape(mddev, conf, sh)) {
6025                 /*
6026                  * Expansion moved on while waiting for a stripe.
6027                  * Expansion could still move past after this
6028                  * test, but as we are holding a reference to
6029                  * 'sh', we know that if that happens,
6030                  *  STRIPE_EXPANDING will get set and the expansion
6031                  * won't proceed until we finish with the stripe.
6032                  */
6033                 ret = STRIPE_SCHEDULE_AND_RETRY;
6034                 goto out_release;
6035         }
6036
6037         if (read_seqcount_retry(&conf->gen_lock, seq)) {
6038                 /* Might have got the wrong stripe_head by accident */
6039                 ret = STRIPE_RETRY;
6040                 goto out_release;
6041         }
6042
6043         if (test_bit(STRIPE_EXPANDING, &sh->state) ||
6044             !add_all_stripe_bios(conf, ctx, sh, bi, rw, previous)) {
6045                 /*
6046                  * Stripe is busy expanding or add failed due to
6047                  * overlap. Flush everything and wait a while.
6048                  */
6049                 md_wakeup_thread(mddev->thread);
6050                 ret = STRIPE_SCHEDULE_AND_RETRY;
6051                 goto out_release;
6052         }
6053
6054         if (stripe_can_batch(sh)) {
6055                 stripe_add_to_batch_list(conf, sh, ctx->batch_last);
6056                 if (ctx->batch_last)
6057                         raid5_release_stripe(ctx->batch_last);
6058                 atomic_inc(&sh->count);
6059                 ctx->batch_last = sh;
6060         }
6061
6062         if (ctx->do_flush) {
6063                 set_bit(STRIPE_R5C_PREFLUSH, &sh->state);
6064                 /* we only need flush for one stripe */
6065                 ctx->do_flush = false;
6066         }
6067
6068         set_bit(STRIPE_HANDLE, &sh->state);
6069         clear_bit(STRIPE_DELAYED, &sh->state);
6070         if ((!sh->batch_head || sh == sh->batch_head) &&
6071             (bi->bi_opf & REQ_SYNC) &&
6072             !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
6073                 atomic_inc(&conf->preread_active_stripes);
6074
6075         release_stripe_plug(mddev, sh);
6076         return STRIPE_SUCCESS;
6077
6078 out_release:
6079         raid5_release_stripe(sh);
6080         return ret;
6081 }
6082
6083 static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
6084 {
6085         DEFINE_WAIT_FUNC(wait, woken_wake_function);
6086         struct r5conf *conf = mddev->private;
6087         sector_t logical_sector;
6088         struct stripe_request_ctx ctx = {};
6089         const int rw = bio_data_dir(bi);
6090         enum stripe_result res;
6091         int s, stripe_cnt;
6092
6093         if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
6094                 int ret = log_handle_flush_request(conf, bi);
6095
6096                 if (ret == 0)
6097                         return true;
6098                 if (ret == -ENODEV) {
6099                         if (md_flush_request(mddev, bi))
6100                                 return true;
6101                 }
6102                 /* ret == -EAGAIN, fallback */
6103                 /*
6104                  * if r5l_handle_flush_request() didn't clear REQ_PREFLUSH,
6105                  * we need to flush journal device
6106                  */
6107                 ctx.do_flush = bi->bi_opf & REQ_PREFLUSH;
6108         }
6109
6110         if (!md_write_start(mddev, bi))
6111                 return false;
6112         /*
6113          * If array is degraded, better not do chunk aligned read because
6114          * later we might have to read it again in order to reconstruct
6115          * data on failed drives.
6116          */
6117         if (rw == READ && mddev->degraded == 0 &&
6118             mddev->reshape_position == MaxSector) {
6119                 bi = chunk_aligned_read(mddev, bi);
6120                 if (!bi)
6121                         return true;
6122         }
6123
6124         if (unlikely(bio_op(bi) == REQ_OP_DISCARD)) {
6125                 make_discard_request(mddev, bi);
6126                 md_write_end(mddev);
6127                 return true;
6128         }
6129
6130         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
6131         ctx.first_sector = logical_sector;
6132         ctx.last_sector = bio_end_sector(bi);
6133         bi->bi_next = NULL;
6134
6135         stripe_cnt = DIV_ROUND_UP_SECTOR_T(ctx.last_sector - logical_sector,
6136                                            RAID5_STRIPE_SECTORS(conf));
6137         bitmap_set(ctx.sectors_to_do, 0, stripe_cnt);
6138
6139         pr_debug("raid456: %s, logical %llu to %llu\n", __func__,
6140                  bi->bi_iter.bi_sector, ctx.last_sector);
6141
6142         /* Bail out if conflicts with reshape and REQ_NOWAIT is set */
6143         if ((bi->bi_opf & REQ_NOWAIT) &&
6144             (conf->reshape_progress != MaxSector) &&
6145             !ahead_of_reshape(mddev, logical_sector, conf->reshape_progress) &&
6146             ahead_of_reshape(mddev, logical_sector, conf->reshape_safe)) {
6147                 bio_wouldblock_error(bi);
6148                 if (rw == WRITE)
6149                         md_write_end(mddev);
6150                 return true;
6151         }
6152         md_account_bio(mddev, &bi);
6153
6154         add_wait_queue(&conf->wait_for_overlap, &wait);
6155         while (1) {
6156                 res = make_stripe_request(mddev, conf, &ctx, logical_sector,
6157                                           bi);
6158                 if (res == STRIPE_FAIL)
6159                         break;
6160
6161                 if (res == STRIPE_RETRY)
6162                         continue;
6163
6164                 if (res == STRIPE_SCHEDULE_AND_RETRY) {
6165                         /*
6166                          * Must release the reference to batch_last before
6167                          * scheduling and waiting for work to be done,
6168                          * otherwise the batch_last stripe head could prevent
6169                          * raid5_activate_delayed() from making progress
6170                          * and thus deadlocking.
6171                          */
6172                         if (ctx.batch_last) {
6173                                 raid5_release_stripe(ctx.batch_last);
6174                                 ctx.batch_last = NULL;
6175                         }
6176
6177                         wait_woken(&wait, TASK_UNINTERRUPTIBLE,
6178                                    MAX_SCHEDULE_TIMEOUT);
6179                         continue;
6180                 }
6181
6182                 s = find_first_bit(ctx.sectors_to_do, stripe_cnt);
6183                 if (s == stripe_cnt)
6184                         break;
6185
6186                 logical_sector = ctx.first_sector +
6187                         (s << RAID5_STRIPE_SHIFT(conf));
6188         }
6189         remove_wait_queue(&conf->wait_for_overlap, &wait);
6190
6191         if (ctx.batch_last)
6192                 raid5_release_stripe(ctx.batch_last);
6193
6194         if (rw == WRITE)
6195                 md_write_end(mddev);
6196         bio_endio(bi);
6197         return true;
6198 }
6199
6200 static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
6201
6202 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
6203 {
6204         /* reshaping is quite different to recovery/resync so it is
6205          * handled quite separately ... here.
6206          *
6207          * On each call to sync_request, we gather one chunk worth of
6208          * destination stripes and flag them as expanding.
6209          * Then we find all the source stripes and request reads.
6210          * As the reads complete, handle_stripe will copy the data
6211          * into the destination stripe and release that stripe.
6212          */
6213         struct r5conf *conf = mddev->private;
6214         struct stripe_head *sh;
6215         struct md_rdev *rdev;
6216         sector_t first_sector, last_sector;
6217         int raid_disks = conf->previous_raid_disks;
6218         int data_disks = raid_disks - conf->max_degraded;
6219         int new_data_disks = conf->raid_disks - conf->max_degraded;
6220         int i;
6221         int dd_idx;
6222         sector_t writepos, readpos, safepos;
6223         sector_t stripe_addr;
6224         int reshape_sectors;
6225         struct list_head stripes;
6226         sector_t retn;
6227
6228         if (sector_nr == 0) {
6229                 /* If restarting in the middle, skip the initial sectors */
6230                 if (mddev->reshape_backwards &&
6231                     conf->reshape_progress < raid5_size(mddev, 0, 0)) {
6232                         sector_nr = raid5_size(mddev, 0, 0)
6233                                 - conf->reshape_progress;
6234                 } else if (mddev->reshape_backwards &&
6235                            conf->reshape_progress == MaxSector) {
6236                         /* shouldn't happen, but just in case, finish up.*/
6237                         sector_nr = MaxSector;
6238                 } else if (!mddev->reshape_backwards &&
6239                            conf->reshape_progress > 0)
6240                         sector_nr = conf->reshape_progress;
6241                 sector_div(sector_nr, new_data_disks);
6242                 if (sector_nr) {
6243                         mddev->curr_resync_completed = sector_nr;
6244                         sysfs_notify_dirent_safe(mddev->sysfs_completed);
6245                         *skipped = 1;
6246                         retn = sector_nr;
6247                         goto finish;
6248                 }
6249         }
6250
6251         /* We need to process a full chunk at a time.
6252          * If old and new chunk sizes differ, we need to process the
6253          * largest of these
6254          */
6255
6256         reshape_sectors = max(conf->chunk_sectors, conf->prev_chunk_sectors);
6257
6258         /* We update the metadata at least every 10 seconds, or when
6259          * the data about to be copied would over-write the source of
6260          * the data at the front of the range.  i.e. one new_stripe
6261          * along from reshape_progress new_maps to after where
6262          * reshape_safe old_maps to
6263          */
6264         writepos = conf->reshape_progress;
6265         sector_div(writepos, new_data_disks);
6266         readpos = conf->reshape_progress;
6267         sector_div(readpos, data_disks);
6268         safepos = conf->reshape_safe;
6269         sector_div(safepos, data_disks);
6270         if (mddev->reshape_backwards) {
6271                 BUG_ON(writepos < reshape_sectors);
6272                 writepos -= reshape_sectors;
6273                 readpos += reshape_sectors;
6274                 safepos += reshape_sectors;
6275         } else {
6276                 writepos += reshape_sectors;
6277                 /* readpos and safepos are worst-case calculations.
6278                  * A negative number is overly pessimistic, and causes
6279                  * obvious problems for unsigned storage.  So clip to 0.
6280                  */
6281                 readpos -= min_t(sector_t, reshape_sectors, readpos);
6282                 safepos -= min_t(sector_t, reshape_sectors, safepos);
6283         }
6284
6285         /* Having calculated the 'writepos' possibly use it
6286          * to set 'stripe_addr' which is where we will write to.
6287          */
6288         if (mddev->reshape_backwards) {
6289                 BUG_ON(conf->reshape_progress == 0);
6290                 stripe_addr = writepos;
6291                 BUG_ON((mddev->dev_sectors &
6292                         ~((sector_t)reshape_sectors - 1))
6293                        - reshape_sectors - stripe_addr
6294                        != sector_nr);
6295         } else {
6296                 BUG_ON(writepos != sector_nr + reshape_sectors);
6297                 stripe_addr = sector_nr;
6298         }
6299
6300         /* 'writepos' is the most advanced device address we might write.
6301          * 'readpos' is the least advanced device address we might read.
6302          * 'safepos' is the least address recorded in the metadata as having
6303          *     been reshaped.
6304          * If there is a min_offset_diff, these are adjusted either by
6305          * increasing the safepos/readpos if diff is negative, or
6306          * increasing writepos if diff is positive.
6307          * If 'readpos' is then behind 'writepos', there is no way that we can
6308          * ensure safety in the face of a crash - that must be done by userspace
6309          * making a backup of the data.  So in that case there is no particular
6310          * rush to update metadata.
6311          * Otherwise if 'safepos' is behind 'writepos', then we really need to
6312          * update the metadata to advance 'safepos' to match 'readpos' so that
6313          * we can be safe in the event of a crash.
6314          * So we insist on updating metadata if safepos is behind writepos and
6315          * readpos is beyond writepos.
6316          * In any case, update the metadata every 10 seconds.
6317          * Maybe that number should be configurable, but I'm not sure it is
6318          * worth it.... maybe it could be a multiple of safemode_delay???
6319          */
6320         if (conf->min_offset_diff < 0) {
6321                 safepos += -conf->min_offset_diff;
6322                 readpos += -conf->min_offset_diff;
6323         } else
6324                 writepos += conf->min_offset_diff;
6325
6326         if ((mddev->reshape_backwards
6327              ? (safepos > writepos && readpos < writepos)
6328              : (safepos < writepos && readpos > writepos)) ||
6329             time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
6330                 /* Cannot proceed until we've updated the superblock... */
6331                 wait_event(conf->wait_for_overlap,
6332                            atomic_read(&conf->reshape_stripes)==0
6333                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6334                 if (atomic_read(&conf->reshape_stripes) != 0)
6335                         return 0;
6336                 mddev->reshape_position = conf->reshape_progress;
6337                 mddev->curr_resync_completed = sector_nr;
6338                 if (!mddev->reshape_backwards)
6339                         /* Can update recovery_offset */
6340                         rdev_for_each(rdev, mddev)
6341                                 if (rdev->raid_disk >= 0 &&
6342                                     !test_bit(Journal, &rdev->flags) &&
6343                                     !test_bit(In_sync, &rdev->flags) &&
6344                                     rdev->recovery_offset < sector_nr)
6345                                         rdev->recovery_offset = sector_nr;
6346
6347                 conf->reshape_checkpoint = jiffies;
6348                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
6349                 md_wakeup_thread(mddev->thread);
6350                 wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
6351                            test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6352                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6353                         return 0;
6354                 spin_lock_irq(&conf->device_lock);
6355                 conf->reshape_safe = mddev->reshape_position;
6356                 spin_unlock_irq(&conf->device_lock);
6357                 wake_up(&conf->wait_for_overlap);
6358                 sysfs_notify_dirent_safe(mddev->sysfs_completed);
6359         }
6360
6361         INIT_LIST_HEAD(&stripes);
6362         for (i = 0; i < reshape_sectors; i += RAID5_STRIPE_SECTORS(conf)) {
6363                 int j;
6364                 int skipped_disk = 0;
6365                 sh = raid5_get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
6366                 set_bit(STRIPE_EXPANDING, &sh->state);
6367                 atomic_inc(&conf->reshape_stripes);
6368                 /* If any of this stripe is beyond the end of the old
6369                  * array, then we need to zero those blocks
6370                  */
6371                 for (j=sh->disks; j--;) {
6372                         sector_t s;
6373                         if (j == sh->pd_idx)
6374                                 continue;
6375                         if (conf->level == 6 &&
6376                             j == sh->qd_idx)
6377                                 continue;
6378                         s = raid5_compute_blocknr(sh, j, 0);
6379                         if (s < raid5_size(mddev, 0, 0)) {
6380                                 skipped_disk = 1;
6381                                 continue;
6382                         }
6383                         memset(page_address(sh->dev[j].page), 0, RAID5_STRIPE_SIZE(conf));
6384                         set_bit(R5_Expanded, &sh->dev[j].flags);
6385                         set_bit(R5_UPTODATE, &sh->dev[j].flags);
6386                 }
6387                 if (!skipped_disk) {
6388                         set_bit(STRIPE_EXPAND_READY, &sh->state);
6389                         set_bit(STRIPE_HANDLE, &sh->state);
6390                 }
6391                 list_add(&sh->lru, &stripes);
6392         }
6393         spin_lock_irq(&conf->device_lock);
6394         if (mddev->reshape_backwards)
6395                 conf->reshape_progress -= reshape_sectors * new_data_disks;
6396         else
6397                 conf->reshape_progress += reshape_sectors * new_data_disks;
6398         spin_unlock_irq(&conf->device_lock);
6399         /* Ok, those stripe are ready. We can start scheduling
6400          * reads on the source stripes.
6401          * The source stripes are determined by mapping the first and last
6402          * block on the destination stripes.
6403          */
6404         first_sector =
6405                 raid5_compute_sector(conf, stripe_addr*(new_data_disks),
6406                                      1, &dd_idx, NULL);
6407         last_sector =
6408                 raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
6409                                             * new_data_disks - 1),
6410                                      1, &dd_idx, NULL);
6411         if (last_sector >= mddev->dev_sectors)
6412                 last_sector = mddev->dev_sectors - 1;
6413         while (first_sector <= last_sector) {
6414                 sh = raid5_get_active_stripe(conf, first_sector, 1, 0, 1);
6415                 set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
6416                 set_bit(STRIPE_HANDLE, &sh->state);
6417                 raid5_release_stripe(sh);
6418                 first_sector += RAID5_STRIPE_SECTORS(conf);
6419         }
6420         /* Now that the sources are clearly marked, we can release
6421          * the destination stripes
6422          */
6423         while (!list_empty(&stripes)) {
6424                 sh = list_entry(stripes.next, struct stripe_head, lru);
6425                 list_del_init(&sh->lru);
6426                 raid5_release_stripe(sh);
6427         }
6428         /* If this takes us to the resync_max point where we have to pause,
6429          * then we need to write out the superblock.
6430          */
6431         sector_nr += reshape_sectors;
6432         retn = reshape_sectors;
6433 finish:
6434         if (mddev->curr_resync_completed > mddev->resync_max ||
6435             (sector_nr - mddev->curr_resync_completed) * 2
6436             >= mddev->resync_max - mddev->curr_resync_completed) {
6437                 /* Cannot proceed until we've updated the superblock... */
6438                 wait_event(conf->wait_for_overlap,
6439                            atomic_read(&conf->reshape_stripes) == 0
6440                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6441                 if (atomic_read(&conf->reshape_stripes) != 0)
6442                         goto ret;
6443                 mddev->reshape_position = conf->reshape_progress;
6444                 mddev->curr_resync_completed = sector_nr;
6445                 if (!mddev->reshape_backwards)
6446                         /* Can update recovery_offset */
6447                         rdev_for_each(rdev, mddev)
6448                                 if (rdev->raid_disk >= 0 &&
6449                                     !test_bit(Journal, &rdev->flags) &&
6450                                     !test_bit(In_sync, &rdev->flags) &&
6451                                     rdev->recovery_offset < sector_nr)
6452                                         rdev->recovery_offset = sector_nr;
6453                 conf->reshape_checkpoint = jiffies;
6454                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
6455                 md_wakeup_thread(mddev->thread);
6456                 wait_event(mddev->sb_wait,
6457                            !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)
6458                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6459                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6460                         goto ret;
6461                 spin_lock_irq(&conf->device_lock);
6462                 conf->reshape_safe = mddev->reshape_position;
6463                 spin_unlock_irq(&conf->device_lock);
6464                 wake_up(&conf->wait_for_overlap);
6465                 sysfs_notify_dirent_safe(mddev->sysfs_completed);
6466         }
6467 ret:
6468         return retn;
6469 }
6470
6471 static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_nr,
6472                                           int *skipped)
6473 {
6474         struct r5conf *conf = mddev->private;
6475         struct stripe_head *sh;
6476         sector_t max_sector = mddev->dev_sectors;
6477         sector_t sync_blocks;
6478         int still_degraded = 0;
6479         int i;
6480
6481         if (sector_nr >= max_sector) {
6482                 /* just being told to finish up .. nothing much to do */
6483
6484                 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
6485                         end_reshape(conf);
6486                         return 0;
6487                 }
6488
6489                 if (mddev->curr_resync < max_sector) /* aborted */
6490                         md_bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
6491                                            &sync_blocks, 1);
6492                 else /* completed sync */
6493                         conf->fullsync = 0;
6494                 md_bitmap_close_sync(mddev->bitmap);
6495
6496                 return 0;
6497         }
6498
6499         /* Allow raid5_quiesce to complete */
6500         wait_event(conf->wait_for_overlap, conf->quiesce != 2);
6501
6502         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6503                 return reshape_request(mddev, sector_nr, skipped);
6504
6505         /* No need to check resync_max as we never do more than one
6506          * stripe, and as resync_max will always be on a chunk boundary,
6507          * if the check in md_do_sync didn't fire, there is no chance
6508          * of overstepping resync_max here
6509          */
6510
6511         /* if there is too many failed drives and we are trying
6512          * to resync, then assert that we are finished, because there is
6513          * nothing we can do.
6514          */
6515         if (mddev->degraded >= conf->max_degraded &&
6516             test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
6517                 sector_t rv = mddev->dev_sectors - sector_nr;
6518                 *skipped = 1;
6519                 return rv;
6520         }
6521         if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
6522             !conf->fullsync &&
6523             !md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
6524             sync_blocks >= RAID5_STRIPE_SECTORS(conf)) {
6525                 /* we can skip this block, and probably more */
6526                 do_div(sync_blocks, RAID5_STRIPE_SECTORS(conf));
6527                 *skipped = 1;
6528                 /* keep things rounded to whole stripes */
6529                 return sync_blocks * RAID5_STRIPE_SECTORS(conf);
6530         }
6531
6532         md_bitmap_cond_end_sync(mddev->bitmap, sector_nr, false);
6533
6534         sh = raid5_get_active_stripe(conf, sector_nr, 0, 1, 0);
6535         if (sh == NULL) {
6536                 sh = raid5_get_active_stripe(conf, sector_nr, 0, 0, 0);
6537                 /* make sure we don't swamp the stripe cache if someone else
6538                  * is trying to get access
6539                  */
6540                 schedule_timeout_uninterruptible(1);
6541         }
6542         /* Need to check if array will still be degraded after recovery/resync
6543          * Note in case of > 1 drive failures it's possible we're rebuilding
6544          * one drive while leaving another faulty drive in array.
6545          */
6546         rcu_read_lock();
6547         for (i = 0; i < conf->raid_disks; i++) {
6548                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
6549
6550                 if (rdev == NULL || test_bit(Faulty, &rdev->flags))
6551                         still_degraded = 1;
6552         }
6553         rcu_read_unlock();
6554
6555         md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
6556
6557         set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
6558         set_bit(STRIPE_HANDLE, &sh->state);
6559
6560         raid5_release_stripe(sh);
6561
6562         return RAID5_STRIPE_SECTORS(conf);
6563 }
6564
6565 static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio,
6566                                unsigned int offset)
6567 {
6568         /* We may not be able to submit a whole bio at once as there
6569          * may not be enough stripe_heads available.
6570          * We cannot pre-allocate enough stripe_heads as we may need
6571          * more than exist in the cache (if we allow ever large chunks).
6572          * So we do one stripe head at a time and record in
6573          * ->bi_hw_segments how many have been done.
6574          *
6575          * We *know* that this entire raid_bio is in one chunk, so
6576          * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
6577          */
6578         struct stripe_head *sh;
6579         int dd_idx;
6580         sector_t sector, logical_sector, last_sector;
6581         int scnt = 0;
6582         int handled = 0;
6583
6584         logical_sector = raid_bio->bi_iter.bi_sector &
6585                 ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
6586         sector = raid5_compute_sector(conf, logical_sector,
6587                                       0, &dd_idx, NULL);
6588         last_sector = bio_end_sector(raid_bio);
6589
6590         for (; logical_sector < last_sector;
6591              logical_sector += RAID5_STRIPE_SECTORS(conf),
6592                      sector += RAID5_STRIPE_SECTORS(conf),
6593                      scnt++) {
6594
6595                 if (scnt < offset)
6596                         /* already done this stripe */
6597                         continue;
6598
6599                 sh = raid5_get_active_stripe(conf, sector, 0, 1, 1);
6600
6601                 if (!sh) {
6602                         /* failed to get a stripe - must wait */
6603                         conf->retry_read_aligned = raid_bio;
6604                         conf->retry_read_offset = scnt;
6605                         return handled;
6606                 }
6607
6608                 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0, 0)) {
6609                         raid5_release_stripe(sh);
6610                         conf->retry_read_aligned = raid_bio;
6611                         conf->retry_read_offset = scnt;
6612                         return handled;
6613                 }
6614
6615                 set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
6616                 handle_stripe(sh);
6617                 raid5_release_stripe(sh);
6618                 handled++;
6619         }
6620
6621         bio_endio(raid_bio);
6622
6623         if (atomic_dec_and_test(&conf->active_aligned_reads))
6624                 wake_up(&conf->wait_for_quiescent);
6625         return handled;
6626 }
6627
6628 static int handle_active_stripes(struct r5conf *conf, int group,
6629                                  struct r5worker *worker,
6630                                  struct list_head *temp_inactive_list)
6631                 __must_hold(&conf->device_lock)
6632 {
6633         struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
6634         int i, batch_size = 0, hash;
6635         bool release_inactive = false;
6636
6637         while (batch_size < MAX_STRIPE_BATCH &&
6638                         (sh = __get_priority_stripe(conf, group)) != NULL)
6639                 batch[batch_size++] = sh;
6640
6641         if (batch_size == 0) {
6642                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6643                         if (!list_empty(temp_inactive_list + i))
6644                                 break;
6645                 if (i == NR_STRIPE_HASH_LOCKS) {
6646                         spin_unlock_irq(&conf->device_lock);
6647                         log_flush_stripe_to_raid(conf);
6648                         spin_lock_irq(&conf->device_lock);
6649                         return batch_size;
6650                 }
6651                 release_inactive = true;
6652         }
6653         spin_unlock_irq(&conf->device_lock);
6654
6655         release_inactive_stripe_list(conf, temp_inactive_list,
6656                                      NR_STRIPE_HASH_LOCKS);
6657
6658         r5l_flush_stripe_to_raid(conf->log);
6659         if (release_inactive) {
6660                 spin_lock_irq(&conf->device_lock);
6661                 return 0;
6662         }
6663
6664         for (i = 0; i < batch_size; i++)
6665                 handle_stripe(batch[i]);
6666         log_write_stripe_run(conf);
6667
6668         cond_resched();
6669
6670         spin_lock_irq(&conf->device_lock);
6671         for (i = 0; i < batch_size; i++) {
6672                 hash = batch[i]->hash_lock_index;
6673                 __release_stripe(conf, batch[i], &temp_inactive_list[hash]);
6674         }
6675         return batch_size;
6676 }
6677
6678 static void raid5_do_work(struct work_struct *work)
6679 {
6680         struct r5worker *worker = container_of(work, struct r5worker, work);
6681         struct r5worker_group *group = worker->group;
6682         struct r5conf *conf = group->conf;
6683         struct mddev *mddev = conf->mddev;
6684         int group_id = group - conf->worker_groups;
6685         int handled;
6686         struct blk_plug plug;
6687
6688         pr_debug("+++ raid5worker active\n");
6689
6690         blk_start_plug(&plug);
6691         handled = 0;
6692         spin_lock_irq(&conf->device_lock);
6693         while (1) {
6694                 int batch_size, released;
6695
6696                 released = release_stripe_list(conf, worker->temp_inactive_list);
6697
6698                 batch_size = handle_active_stripes(conf, group_id, worker,
6699                                                    worker->temp_inactive_list);
6700                 worker->working = false;
6701                 if (!batch_size && !released)
6702                         break;
6703                 handled += batch_size;
6704                 wait_event_lock_irq(mddev->sb_wait,
6705                         !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
6706                         conf->device_lock);
6707         }
6708         pr_debug("%d stripes handled\n", handled);
6709
6710         spin_unlock_irq(&conf->device_lock);
6711
6712         flush_deferred_bios(conf);
6713
6714         r5l_flush_stripe_to_raid(conf->log);
6715
6716         async_tx_issue_pending_all();
6717         blk_finish_plug(&plug);
6718
6719         pr_debug("--- raid5worker inactive\n");
6720 }
6721
6722 /*
6723  * This is our raid5 kernel thread.
6724  *
6725  * We scan the hash table for stripes which can be handled now.
6726  * During the scan, completed stripes are saved for us by the interrupt
6727  * handler, so that they will not have to wait for our next wakeup.
6728  */
6729 static void raid5d(struct md_thread *thread)
6730 {
6731         struct mddev *mddev = thread->mddev;
6732         struct r5conf *conf = mddev->private;
6733         int handled;
6734         struct blk_plug plug;
6735
6736         pr_debug("+++ raid5d active\n");
6737
6738         md_check_recovery(mddev);
6739
6740         blk_start_plug(&plug);
6741         handled = 0;
6742         spin_lock_irq(&conf->device_lock);
6743         while (1) {
6744                 struct bio *bio;
6745                 int batch_size, released;
6746                 unsigned int offset;
6747
6748                 released = release_stripe_list(conf, conf->temp_inactive_list);
6749                 if (released)
6750                         clear_bit(R5_DID_ALLOC, &conf->cache_state);
6751
6752                 if (
6753                     !list_empty(&conf->bitmap_list)) {
6754                         /* Now is a good time to flush some bitmap updates */
6755                         conf->seq_flush++;
6756                         spin_unlock_irq(&conf->device_lock);
6757                         md_bitmap_unplug(mddev->bitmap);
6758                         spin_lock_irq(&conf->device_lock);
6759                         conf->seq_write = conf->seq_flush;
6760                         activate_bit_delay(conf, conf->temp_inactive_list);
6761                 }
6762                 raid5_activate_delayed(conf);
6763
6764                 while ((bio = remove_bio_from_retry(conf, &offset))) {
6765                         int ok;
6766                         spin_unlock_irq(&conf->device_lock);
6767                         ok = retry_aligned_read(conf, bio, offset);
6768                         spin_lock_irq(&conf->device_lock);
6769                         if (!ok)
6770                                 break;
6771                         handled++;
6772                 }
6773
6774                 batch_size = handle_active_stripes(conf, ANY_GROUP, NULL,
6775                                                    conf->temp_inactive_list);
6776                 if (!batch_size && !released)
6777                         break;
6778                 handled += batch_size;
6779
6780                 if (mddev->sb_flags & ~(1 << MD_SB_CHANGE_PENDING)) {
6781                         spin_unlock_irq(&conf->device_lock);
6782                         md_check_recovery(mddev);
6783                         spin_lock_irq(&conf->device_lock);
6784                 }
6785         }
6786         pr_debug("%d stripes handled\n", handled);
6787
6788         spin_unlock_irq(&conf->device_lock);
6789         if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state) &&
6790             mutex_trylock(&conf->cache_size_mutex)) {
6791                 grow_one_stripe(conf, __GFP_NOWARN);
6792                 /* Set flag even if allocation failed.  This helps
6793                  * slow down allocation requests when mem is short
6794                  */
6795                 set_bit(R5_DID_ALLOC, &conf->cache_state);
6796                 mutex_unlock(&conf->cache_size_mutex);
6797         }
6798
6799         flush_deferred_bios(conf);
6800
6801         r5l_flush_stripe_to_raid(conf->log);
6802
6803         async_tx_issue_pending_all();
6804         blk_finish_plug(&plug);
6805
6806         pr_debug("--- raid5d inactive\n");
6807 }
6808
6809 static ssize_t
6810 raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
6811 {
6812         struct r5conf *conf;
6813         int ret = 0;
6814         spin_lock(&mddev->lock);
6815         conf = mddev->private;
6816         if (conf)
6817                 ret = sprintf(page, "%d\n", conf->min_nr_stripes);
6818         spin_unlock(&mddev->lock);
6819         return ret;
6820 }
6821
6822 int
6823 raid5_set_cache_size(struct mddev *mddev, int size)
6824 {
6825         int result = 0;
6826         struct r5conf *conf = mddev->private;
6827
6828         if (size <= 16 || size > 32768)
6829                 return -EINVAL;
6830
6831         conf->min_nr_stripes = size;
6832         mutex_lock(&conf->cache_size_mutex);
6833         while (size < conf->max_nr_stripes &&
6834                drop_one_stripe(conf))
6835                 ;
6836         mutex_unlock(&conf->cache_size_mutex);
6837
6838         md_allow_write(mddev);
6839
6840         mutex_lock(&conf->cache_size_mutex);
6841         while (size > conf->max_nr_stripes)
6842                 if (!grow_one_stripe(conf, GFP_KERNEL)) {
6843                         conf->min_nr_stripes = conf->max_nr_stripes;
6844                         result = -ENOMEM;
6845                         break;
6846                 }
6847         mutex_unlock(&conf->cache_size_mutex);
6848
6849         return result;
6850 }
6851 EXPORT_SYMBOL(raid5_set_cache_size);
6852
6853 static ssize_t
6854 raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
6855 {
6856         struct r5conf *conf;
6857         unsigned long new;
6858         int err;
6859
6860         if (len >= PAGE_SIZE)
6861                 return -EINVAL;
6862         if (kstrtoul(page, 10, &new))
6863                 return -EINVAL;
6864         err = mddev_lock(mddev);
6865         if (err)
6866                 return err;
6867         conf = mddev->private;
6868         if (!conf)
6869                 err = -ENODEV;
6870         else
6871                 err = raid5_set_cache_size(mddev, new);
6872         mddev_unlock(mddev);
6873
6874         return err ?: len;
6875 }
6876
6877 static struct md_sysfs_entry
6878 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
6879                                 raid5_show_stripe_cache_size,
6880                                 raid5_store_stripe_cache_size);
6881
6882 static ssize_t
6883 raid5_show_rmw_level(struct mddev  *mddev, char *page)
6884 {
6885         struct r5conf *conf = mddev->private;
6886         if (conf)
6887                 return sprintf(page, "%d\n", conf->rmw_level);
6888         else
6889                 return 0;
6890 }
6891
6892 static ssize_t
6893 raid5_store_rmw_level(struct mddev  *mddev, const char *page, size_t len)
6894 {
6895         struct r5conf *conf = mddev->private;
6896         unsigned long new;
6897
6898         if (!conf)
6899                 return -ENODEV;
6900
6901         if (len >= PAGE_SIZE)
6902                 return -EINVAL;
6903
6904         if (kstrtoul(page, 10, &new))
6905                 return -EINVAL;
6906
6907         if (new != PARITY_DISABLE_RMW && !raid6_call.xor_syndrome)
6908                 return -EINVAL;
6909
6910         if (new != PARITY_DISABLE_RMW &&
6911             new != PARITY_ENABLE_RMW &&
6912             new != PARITY_PREFER_RMW)
6913                 return -EINVAL;
6914
6915         conf->rmw_level = new;
6916         return len;
6917 }
6918
6919 static struct md_sysfs_entry
6920 raid5_rmw_level = __ATTR(rmw_level, S_IRUGO | S_IWUSR,
6921                          raid5_show_rmw_level,
6922                          raid5_store_rmw_level);
6923
6924 static ssize_t
6925 raid5_show_stripe_size(struct mddev  *mddev, char *page)
6926 {
6927         struct r5conf *conf;
6928         int ret = 0;
6929
6930         spin_lock(&mddev->lock);
6931         conf = mddev->private;
6932         if (conf)
6933                 ret = sprintf(page, "%lu\n", RAID5_STRIPE_SIZE(conf));
6934         spin_unlock(&mddev->lock);
6935         return ret;
6936 }
6937
6938 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
6939 static ssize_t
6940 raid5_store_stripe_size(struct mddev  *mddev, const char *page, size_t len)
6941 {
6942         struct r5conf *conf;
6943         unsigned long new;
6944         int err;
6945         int size;
6946
6947         if (len >= PAGE_SIZE)
6948                 return -EINVAL;
6949         if (kstrtoul(page, 10, &new))
6950                 return -EINVAL;
6951
6952         /*
6953          * The value should not be bigger than PAGE_SIZE. It requires to
6954          * be multiple of DEFAULT_STRIPE_SIZE and the value should be power
6955          * of two.
6956          */
6957         if (new % DEFAULT_STRIPE_SIZE != 0 ||
6958                         new > PAGE_SIZE || new == 0 ||
6959                         new != roundup_pow_of_two(new))
6960                 return -EINVAL;
6961
6962         err = mddev_lock(mddev);
6963         if (err)
6964                 return err;
6965
6966         conf = mddev->private;
6967         if (!conf) {
6968                 err = -ENODEV;
6969                 goto out_unlock;
6970         }
6971
6972         if (new == conf->stripe_size)
6973                 goto out_unlock;
6974
6975         pr_debug("md/raid: change stripe_size from %lu to %lu\n",
6976                         conf->stripe_size, new);
6977
6978         if (mddev->sync_thread ||
6979                 test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
6980                 mddev->reshape_position != MaxSector ||
6981                 mddev->sysfs_active) {
6982                 err = -EBUSY;
6983                 goto out_unlock;
6984         }
6985
6986         mddev_suspend(mddev);
6987         mutex_lock(&conf->cache_size_mutex);
6988         size = conf->max_nr_stripes;
6989
6990         shrink_stripes(conf);
6991
6992         conf->stripe_size = new;
6993         conf->stripe_shift = ilog2(new) - 9;
6994         conf->stripe_sectors = new >> 9;
6995         if (grow_stripes(conf, size)) {
6996                 pr_warn("md/raid:%s: couldn't allocate buffers\n",
6997                                 mdname(mddev));
6998                 err = -ENOMEM;
6999         }
7000         mutex_unlock(&conf->cache_size_mutex);
7001         mddev_resume(mddev);
7002
7003 out_unlock:
7004         mddev_unlock(mddev);
7005         return err ?: len;
7006 }
7007
7008 static struct md_sysfs_entry
7009 raid5_stripe_size = __ATTR(stripe_size, 0644,
7010                          raid5_show_stripe_size,
7011                          raid5_store_stripe_size);
7012 #else
7013 static struct md_sysfs_entry
7014 raid5_stripe_size = __ATTR(stripe_size, 0444,
7015                          raid5_show_stripe_size,
7016                          NULL);
7017 #endif
7018
7019 static ssize_t
7020 raid5_show_preread_threshold(struct mddev *mddev, char *page)
7021 {
7022         struct r5conf *conf;
7023         int ret = 0;
7024         spin_lock(&mddev->lock);
7025         conf = mddev->private;
7026         if (conf)
7027                 ret = sprintf(page, "%d\n", conf->bypass_threshold);
7028         spin_unlock(&mddev->lock);
7029         return ret;
7030 }
7031
7032 static ssize_t
7033 raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
7034 {
7035         struct r5conf *conf;
7036         unsigned long new;
7037         int err;
7038
7039         if (len >= PAGE_SIZE)
7040                 return -EINVAL;
7041         if (kstrtoul(page, 10, &new))
7042                 return -EINVAL;
7043
7044         err = mddev_lock(mddev);
7045         if (err)
7046                 return err;
7047         conf = mddev->private;
7048         if (!conf)
7049                 err = -ENODEV;
7050         else if (new > conf->min_nr_stripes)
7051                 err = -EINVAL;
7052         else
7053                 conf->bypass_threshold = new;
7054         mddev_unlock(mddev);
7055         return err ?: len;
7056 }
7057
7058 static struct md_sysfs_entry
7059 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
7060                                         S_IRUGO | S_IWUSR,
7061                                         raid5_show_preread_threshold,
7062                                         raid5_store_preread_threshold);
7063
7064 static ssize_t
7065 raid5_show_skip_copy(struct mddev *mddev, char *page)
7066 {
7067         struct r5conf *conf;
7068         int ret = 0;
7069         spin_lock(&mddev->lock);
7070         conf = mddev->private;
7071         if (conf)
7072                 ret = sprintf(page, "%d\n", conf->skip_copy);
7073         spin_unlock(&mddev->lock);
7074         return ret;
7075 }
7076
7077 static ssize_t
7078 raid5_store_skip_copy(struct mddev *mddev, const char *page, size_t len)
7079 {
7080         struct r5conf *conf;
7081         unsigned long new;
7082         int err;
7083
7084         if (len >= PAGE_SIZE)
7085                 return -EINVAL;
7086         if (kstrtoul(page, 10, &new))
7087                 return -EINVAL;
7088         new = !!new;
7089
7090         err = mddev_lock(mddev);
7091         if (err)
7092                 return err;
7093         conf = mddev->private;
7094         if (!conf)
7095                 err = -ENODEV;
7096         else if (new != conf->skip_copy) {
7097                 struct request_queue *q = mddev->queue;
7098
7099                 mddev_suspend(mddev);
7100                 conf->skip_copy = new;
7101                 if (new)
7102                         blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES, q);
7103                 else
7104                         blk_queue_flag_clear(QUEUE_FLAG_STABLE_WRITES, q);
7105                 mddev_resume(mddev);
7106         }
7107         mddev_unlock(mddev);
7108         return err ?: len;
7109 }
7110
7111 static struct md_sysfs_entry
7112 raid5_skip_copy = __ATTR(skip_copy, S_IRUGO | S_IWUSR,
7113                                         raid5_show_skip_copy,
7114                                         raid5_store_skip_copy);
7115
7116 static ssize_t
7117 stripe_cache_active_show(struct mddev *mddev, char *page)
7118 {
7119         struct r5conf *conf = mddev->private;
7120         if (conf)
7121                 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
7122         else
7123                 return 0;
7124 }
7125
7126 static struct md_sysfs_entry
7127 raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
7128
7129 static ssize_t
7130 raid5_show_group_thread_cnt(struct mddev *mddev, char *page)
7131 {
7132         struct r5conf *conf;
7133         int ret = 0;
7134         spin_lock(&mddev->lock);
7135         conf = mddev->private;
7136         if (conf)
7137                 ret = sprintf(page, "%d\n", conf->worker_cnt_per_group);
7138         spin_unlock(&mddev->lock);
7139         return ret;
7140 }
7141
7142 static int alloc_thread_groups(struct r5conf *conf, int cnt,
7143                                int *group_cnt,
7144                                struct r5worker_group **worker_groups);
7145 static ssize_t
7146 raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
7147 {
7148         struct r5conf *conf;
7149         unsigned int new;
7150         int err;
7151         struct r5worker_group *new_groups, *old_groups;
7152         int group_cnt;
7153
7154         if (len >= PAGE_SIZE)
7155                 return -EINVAL;
7156         if (kstrtouint(page, 10, &new))
7157                 return -EINVAL;
7158         /* 8192 should be big enough */
7159         if (new > 8192)
7160                 return -EINVAL;
7161
7162         err = mddev_lock(mddev);
7163         if (err)
7164                 return err;
7165         conf = mddev->private;
7166         if (!conf)
7167                 err = -ENODEV;
7168         else if (new != conf->worker_cnt_per_group) {
7169                 mddev_suspend(mddev);
7170
7171                 old_groups = conf->worker_groups;
7172                 if (old_groups)
7173                         flush_workqueue(raid5_wq);
7174
7175                 err = alloc_thread_groups(conf, new, &group_cnt, &new_groups);
7176                 if (!err) {
7177                         spin_lock_irq(&conf->device_lock);
7178                         conf->group_cnt = group_cnt;
7179                         conf->worker_cnt_per_group = new;
7180                         conf->worker_groups = new_groups;
7181                         spin_unlock_irq(&conf->device_lock);
7182
7183                         if (old_groups)
7184                                 kfree(old_groups[0].workers);
7185                         kfree(old_groups);
7186                 }
7187                 mddev_resume(mddev);
7188         }
7189         mddev_unlock(mddev);
7190
7191         return err ?: len;
7192 }
7193
7194 static struct md_sysfs_entry
7195 raid5_group_thread_cnt = __ATTR(group_thread_cnt, S_IRUGO | S_IWUSR,
7196                                 raid5_show_group_thread_cnt,
7197                                 raid5_store_group_thread_cnt);
7198
7199 static struct attribute *raid5_attrs[] =  {
7200         &raid5_stripecache_size.attr,
7201         &raid5_stripecache_active.attr,
7202         &raid5_preread_bypass_threshold.attr,
7203         &raid5_group_thread_cnt.attr,
7204         &raid5_skip_copy.attr,
7205         &raid5_rmw_level.attr,
7206         &raid5_stripe_size.attr,
7207         &r5c_journal_mode.attr,
7208         &ppl_write_hint.attr,
7209         NULL,
7210 };
7211 static const struct attribute_group raid5_attrs_group = {
7212         .name = NULL,
7213         .attrs = raid5_attrs,
7214 };
7215
7216 static int alloc_thread_groups(struct r5conf *conf, int cnt, int *group_cnt,
7217                                struct r5worker_group **worker_groups)
7218 {
7219         int i, j, k;
7220         ssize_t size;
7221         struct r5worker *workers;
7222
7223         if (cnt == 0) {
7224                 *group_cnt = 0;
7225                 *worker_groups = NULL;
7226                 return 0;
7227         }
7228         *group_cnt = num_possible_nodes();
7229         size = sizeof(struct r5worker) * cnt;
7230         workers = kcalloc(size, *group_cnt, GFP_NOIO);
7231         *worker_groups = kcalloc(*group_cnt, sizeof(struct r5worker_group),
7232                                  GFP_NOIO);
7233         if (!*worker_groups || !workers) {
7234                 kfree(workers);
7235                 kfree(*worker_groups);
7236                 return -ENOMEM;
7237         }
7238
7239         for (i = 0; i < *group_cnt; i++) {
7240                 struct r5worker_group *group;
7241
7242                 group = &(*worker_groups)[i];
7243                 INIT_LIST_HEAD(&group->handle_list);
7244                 INIT_LIST_HEAD(&group->loprio_list);
7245                 group->conf = conf;
7246                 group->workers = workers + i * cnt;
7247
7248                 for (j = 0; j < cnt; j++) {
7249                         struct r5worker *worker = group->workers + j;
7250                         worker->group = group;
7251                         INIT_WORK(&worker->work, raid5_do_work);
7252
7253                         for (k = 0; k < NR_STRIPE_HASH_LOCKS; k++)
7254                                 INIT_LIST_HEAD(worker->temp_inactive_list + k);
7255                 }
7256         }
7257
7258         return 0;
7259 }
7260
7261 static void free_thread_groups(struct r5conf *conf)
7262 {
7263         if (conf->worker_groups)
7264                 kfree(conf->worker_groups[0].workers);
7265         kfree(conf->worker_groups);
7266         conf->worker_groups = NULL;
7267 }
7268
7269 static sector_t
7270 raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
7271 {
7272         struct r5conf *conf = mddev->private;
7273
7274         if (!sectors)
7275                 sectors = mddev->dev_sectors;
7276         if (!raid_disks)
7277                 /* size is defined by the smallest of previous and new size */
7278                 raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
7279
7280         sectors &= ~((sector_t)conf->chunk_sectors - 1);
7281         sectors &= ~((sector_t)conf->prev_chunk_sectors - 1);
7282         return sectors * (raid_disks - conf->max_degraded);
7283 }
7284
7285 static void free_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
7286 {
7287         safe_put_page(percpu->spare_page);
7288         percpu->spare_page = NULL;
7289         kvfree(percpu->scribble);
7290         percpu->scribble = NULL;
7291 }
7292
7293 static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
7294 {
7295         if (conf->level == 6 && !percpu->spare_page) {
7296                 percpu->spare_page = alloc_page(GFP_KERNEL);
7297                 if (!percpu->spare_page)
7298                         return -ENOMEM;
7299         }
7300
7301         if (scribble_alloc(percpu,
7302                            max(conf->raid_disks,
7303                                conf->previous_raid_disks),
7304                            max(conf->chunk_sectors,
7305                                conf->prev_chunk_sectors)
7306                            / RAID5_STRIPE_SECTORS(conf))) {
7307                 free_scratch_buffer(conf, percpu);
7308                 return -ENOMEM;
7309         }
7310
7311         local_lock_init(&percpu->lock);
7312         return 0;
7313 }
7314
7315 static int raid456_cpu_dead(unsigned int cpu, struct hlist_node *node)
7316 {
7317         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
7318
7319         free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));
7320         return 0;
7321 }
7322
7323 static void raid5_free_percpu(struct r5conf *conf)
7324 {
7325         if (!conf->percpu)
7326                 return;
7327
7328         cpuhp_state_remove_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
7329         free_percpu(conf->percpu);
7330 }
7331
7332 static void free_conf(struct r5conf *conf)
7333 {
7334         int i;
7335
7336         log_exit(conf);
7337
7338         unregister_shrinker(&conf->shrinker);
7339         free_thread_groups(conf);
7340         shrink_stripes(conf);
7341         raid5_free_percpu(conf);
7342         for (i = 0; i < conf->pool_size; i++)
7343                 if (conf->disks[i].extra_page)
7344                         put_page(conf->disks[i].extra_page);
7345         kfree(conf->disks);
7346         bioset_exit(&conf->bio_split);
7347         kfree(conf->stripe_hashtbl);
7348         kfree(conf->pending_data);
7349         kfree(conf);
7350 }
7351
7352 static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
7353 {
7354         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
7355         struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);
7356
7357         if (alloc_scratch_buffer(conf, percpu)) {
7358                 pr_warn("%s: failed memory allocation for cpu%u\n",
7359                         __func__, cpu);
7360                 return -ENOMEM;
7361         }
7362         return 0;
7363 }
7364
7365 static int raid5_alloc_percpu(struct r5conf *conf)
7366 {
7367         int err = 0;
7368
7369         conf->percpu = alloc_percpu(struct raid5_percpu);
7370         if (!conf->percpu)
7371                 return -ENOMEM;
7372
7373         err = cpuhp_state_add_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
7374         if (!err) {
7375                 conf->scribble_disks = max(conf->raid_disks,
7376                         conf->previous_raid_disks);
7377                 conf->scribble_sectors = max(conf->chunk_sectors,
7378                         conf->prev_chunk_sectors);
7379         }
7380         return err;
7381 }
7382
7383 static unsigned long raid5_cache_scan(struct shrinker *shrink,
7384                                       struct shrink_control *sc)
7385 {
7386         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
7387         unsigned long ret = SHRINK_STOP;
7388
7389         if (mutex_trylock(&conf->cache_size_mutex)) {
7390                 ret= 0;
7391                 while (ret < sc->nr_to_scan &&
7392                        conf->max_nr_stripes > conf->min_nr_stripes) {
7393                         if (drop_one_stripe(conf) == 0) {
7394                                 ret = SHRINK_STOP;
7395                                 break;
7396                         }
7397                         ret++;
7398                 }
7399                 mutex_unlock(&conf->cache_size_mutex);
7400         }
7401         return ret;
7402 }
7403
7404 static unsigned long raid5_cache_count(struct shrinker *shrink,
7405                                        struct shrink_control *sc)
7406 {
7407         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
7408
7409         if (conf->max_nr_stripes < conf->min_nr_stripes)
7410                 /* unlikely, but not impossible */
7411                 return 0;
7412         return conf->max_nr_stripes - conf->min_nr_stripes;
7413 }
7414
7415 static struct r5conf *setup_conf(struct mddev *mddev)
7416 {
7417         struct r5conf *conf;
7418         int raid_disk, memory, max_disks;
7419         struct md_rdev *rdev;
7420         struct disk_info *disk;
7421         char pers_name[6];
7422         int i;
7423         int group_cnt;
7424         struct r5worker_group *new_group;
7425         int ret = -ENOMEM;
7426
7427         if (mddev->new_level != 5
7428             && mddev->new_level != 4
7429             && mddev->new_level != 6) {
7430                 pr_warn("md/raid:%s: raid level not set to 4/5/6 (%d)\n",
7431                         mdname(mddev), mddev->new_level);
7432                 return ERR_PTR(-EIO);
7433         }
7434         if ((mddev->new_level == 5
7435              && !algorithm_valid_raid5(mddev->new_layout)) ||
7436             (mddev->new_level == 6
7437              && !algorithm_valid_raid6(mddev->new_layout))) {
7438                 pr_warn("md/raid:%s: layout %d not supported\n",
7439                         mdname(mddev), mddev->new_layout);
7440                 return ERR_PTR(-EIO);
7441         }
7442         if (mddev->new_level == 6 && mddev->raid_disks < 4) {
7443                 pr_warn("md/raid:%s: not enough configured devices (%d, minimum 4)\n",
7444                         mdname(mddev), mddev->raid_disks);
7445                 return ERR_PTR(-EINVAL);
7446         }
7447
7448         if (!mddev->new_chunk_sectors ||
7449             (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
7450             !is_power_of_2(mddev->new_chunk_sectors)) {
7451                 pr_warn("md/raid:%s: invalid chunk size %d\n",
7452                         mdname(mddev), mddev->new_chunk_sectors << 9);
7453                 return ERR_PTR(-EINVAL);
7454         }
7455
7456         conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
7457         if (conf == NULL)
7458                 goto abort;
7459
7460 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
7461         conf->stripe_size = DEFAULT_STRIPE_SIZE;
7462         conf->stripe_shift = ilog2(DEFAULT_STRIPE_SIZE) - 9;
7463         conf->stripe_sectors = DEFAULT_STRIPE_SIZE >> 9;
7464 #endif
7465         INIT_LIST_HEAD(&conf->free_list);
7466         INIT_LIST_HEAD(&conf->pending_list);
7467         conf->pending_data = kcalloc(PENDING_IO_MAX,
7468                                      sizeof(struct r5pending_data),
7469                                      GFP_KERNEL);
7470         if (!conf->pending_data)
7471                 goto abort;
7472         for (i = 0; i < PENDING_IO_MAX; i++)
7473                 list_add(&conf->pending_data[i].sibling, &conf->free_list);
7474         /* Don't enable multi-threading by default*/
7475         if (!alloc_thread_groups(conf, 0, &group_cnt, &new_group)) {
7476                 conf->group_cnt = group_cnt;
7477                 conf->worker_cnt_per_group = 0;
7478                 conf->worker_groups = new_group;
7479         } else
7480                 goto abort;
7481         spin_lock_init(&conf->device_lock);
7482         seqcount_spinlock_init(&conf->gen_lock, &conf->device_lock);
7483         mutex_init(&conf->cache_size_mutex);
7484
7485         init_waitqueue_head(&conf->wait_for_quiescent);
7486         init_waitqueue_head(&conf->wait_for_stripe);
7487         init_waitqueue_head(&conf->wait_for_overlap);
7488         INIT_LIST_HEAD(&conf->handle_list);
7489         INIT_LIST_HEAD(&conf->loprio_list);
7490         INIT_LIST_HEAD(&conf->hold_list);
7491         INIT_LIST_HEAD(&conf->delayed_list);
7492         INIT_LIST_HEAD(&conf->bitmap_list);
7493         init_llist_head(&conf->released_stripes);
7494         atomic_set(&conf->active_stripes, 0);
7495         atomic_set(&conf->preread_active_stripes, 0);
7496         atomic_set(&conf->active_aligned_reads, 0);
7497         spin_lock_init(&conf->pending_bios_lock);
7498         conf->batch_bio_dispatch = true;
7499         rdev_for_each(rdev, mddev) {
7500                 if (test_bit(Journal, &rdev->flags))
7501                         continue;
7502                 if (bdev_nonrot(rdev->bdev)) {
7503                         conf->batch_bio_dispatch = false;
7504                         break;
7505                 }
7506         }
7507
7508         conf->bypass_threshold = BYPASS_THRESHOLD;
7509         conf->recovery_disabled = mddev->recovery_disabled - 1;
7510
7511         conf->raid_disks = mddev->raid_disks;
7512         if (mddev->reshape_position == MaxSector)
7513                 conf->previous_raid_disks = mddev->raid_disks;
7514         else
7515                 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
7516         max_disks = max(conf->raid_disks, conf->previous_raid_disks);
7517
7518         conf->disks = kcalloc(max_disks, sizeof(struct disk_info),
7519                               GFP_KERNEL);
7520
7521         if (!conf->disks)
7522                 goto abort;
7523
7524         for (i = 0; i < max_disks; i++) {
7525                 conf->disks[i].extra_page = alloc_page(GFP_KERNEL);
7526                 if (!conf->disks[i].extra_page)
7527                         goto abort;
7528         }
7529
7530         ret = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
7531         if (ret)
7532                 goto abort;
7533         conf->mddev = mddev;
7534
7535         ret = -ENOMEM;
7536         conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL);
7537         if (!conf->stripe_hashtbl)
7538                 goto abort;
7539
7540         /* We init hash_locks[0] separately to that it can be used
7541          * as the reference lock in the spin_lock_nest_lock() call
7542          * in lock_all_device_hash_locks_irq in order to convince
7543          * lockdep that we know what we are doing.
7544          */
7545         spin_lock_init(conf->hash_locks);
7546         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
7547                 spin_lock_init(conf->hash_locks + i);
7548
7549         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
7550                 INIT_LIST_HEAD(conf->inactive_list + i);
7551
7552         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
7553                 INIT_LIST_HEAD(conf->temp_inactive_list + i);
7554
7555         atomic_set(&conf->r5c_cached_full_stripes, 0);
7556         INIT_LIST_HEAD(&conf->r5c_full_stripe_list);
7557         atomic_set(&conf->r5c_cached_partial_stripes, 0);
7558         INIT_LIST_HEAD(&conf->r5c_partial_stripe_list);
7559         atomic_set(&conf->r5c_flushing_full_stripes, 0);
7560         atomic_set(&conf->r5c_flushing_partial_stripes, 0);
7561
7562         conf->level = mddev->new_level;
7563         conf->chunk_sectors = mddev->new_chunk_sectors;
7564         ret = raid5_alloc_percpu(conf);
7565         if (ret)
7566                 goto abort;
7567
7568         pr_debug("raid456: run(%s) called.\n", mdname(mddev));
7569
7570         ret = -EIO;
7571         rdev_for_each(rdev, mddev) {
7572                 raid_disk = rdev->raid_disk;
7573                 if (raid_disk >= max_disks
7574                     || raid_disk < 0 || test_bit(Journal, &rdev->flags))
7575                         continue;
7576                 disk = conf->disks + raid_disk;
7577
7578                 if (test_bit(Replacement, &rdev->flags)) {
7579                         if (disk->replacement)
7580                                 goto abort;
7581                         RCU_INIT_POINTER(disk->replacement, rdev);
7582                 } else {
7583                         if (disk->rdev)
7584                                 goto abort;
7585                         RCU_INIT_POINTER(disk->rdev, rdev);
7586                 }
7587
7588                 if (test_bit(In_sync, &rdev->flags)) {
7589                         pr_info("md/raid:%s: device %pg operational as raid disk %d\n",
7590                                 mdname(mddev), rdev->bdev, raid_disk);
7591                 } else if (rdev->saved_raid_disk != raid_disk)
7592                         /* Cannot rely on bitmap to complete recovery */
7593                         conf->fullsync = 1;
7594         }
7595
7596         conf->level = mddev->new_level;
7597         if (conf->level == 6) {
7598                 conf->max_degraded = 2;
7599                 if (raid6_call.xor_syndrome)
7600                         conf->rmw_level = PARITY_ENABLE_RMW;
7601                 else
7602                         conf->rmw_level = PARITY_DISABLE_RMW;
7603         } else {
7604                 conf->max_degraded = 1;
7605                 conf->rmw_level = PARITY_ENABLE_RMW;
7606         }
7607         conf->algorithm = mddev->new_layout;
7608         conf->reshape_progress = mddev->reshape_position;
7609         if (conf->reshape_progress != MaxSector) {
7610                 conf->prev_chunk_sectors = mddev->chunk_sectors;
7611                 conf->prev_algo = mddev->layout;
7612         } else {
7613                 conf->prev_chunk_sectors = conf->chunk_sectors;
7614                 conf->prev_algo = conf->algorithm;
7615         }
7616
7617         conf->min_nr_stripes = NR_STRIPES;
7618         if (mddev->reshape_position != MaxSector) {
7619                 int stripes = max_t(int,
7620                         ((mddev->chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4,
7621                         ((mddev->new_chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4);
7622                 conf->min_nr_stripes = max(NR_STRIPES, stripes);
7623                 if (conf->min_nr_stripes != NR_STRIPES)
7624                         pr_info("md/raid:%s: force stripe size %d for reshape\n",
7625                                 mdname(mddev), conf->min_nr_stripes);
7626         }
7627         memory = conf->min_nr_stripes * (sizeof(struct stripe_head) +
7628                  max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
7629         atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS);
7630         if (grow_stripes(conf, conf->min_nr_stripes)) {
7631                 pr_warn("md/raid:%s: couldn't allocate %dkB for buffers\n",
7632                         mdname(mddev), memory);
7633                 ret = -ENOMEM;
7634                 goto abort;
7635         } else
7636                 pr_debug("md/raid:%s: allocated %dkB\n", mdname(mddev), memory);
7637         /*
7638          * Losing a stripe head costs more than the time to refill it,
7639          * it reduces the queue depth and so can hurt throughput.
7640          * So set it rather large, scaled by number of devices.
7641          */
7642         conf->shrinker.seeks = DEFAULT_SEEKS * conf->raid_disks * 4;
7643         conf->shrinker.scan_objects = raid5_cache_scan;
7644         conf->shrinker.count_objects = raid5_cache_count;
7645         conf->shrinker.batch = 128;
7646         conf->shrinker.flags = 0;
7647         ret = register_shrinker(&conf->shrinker, "md-raid5:%s", mdname(mddev));
7648         if (ret) {
7649                 pr_warn("md/raid:%s: couldn't register shrinker.\n",
7650                         mdname(mddev));
7651                 goto abort;
7652         }
7653
7654         sprintf(pers_name, "raid%d", mddev->new_level);
7655         conf->thread = md_register_thread(raid5d, mddev, pers_name);
7656         if (!conf->thread) {
7657                 pr_warn("md/raid:%s: couldn't allocate thread.\n",
7658                         mdname(mddev));
7659                 ret = -ENOMEM;
7660                 goto abort;
7661         }
7662
7663         return conf;
7664
7665  abort:
7666         if (conf)
7667                 free_conf(conf);
7668         return ERR_PTR(ret);
7669 }
7670
7671 static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
7672 {
7673         switch (algo) {
7674         case ALGORITHM_PARITY_0:
7675                 if (raid_disk < max_degraded)
7676                         return 1;
7677                 break;
7678         case ALGORITHM_PARITY_N:
7679                 if (raid_disk >= raid_disks - max_degraded)
7680                         return 1;
7681                 break;
7682         case ALGORITHM_PARITY_0_6:
7683                 if (raid_disk == 0 ||
7684                     raid_disk == raid_disks - 1)
7685                         return 1;
7686                 break;
7687         case ALGORITHM_LEFT_ASYMMETRIC_6:
7688         case ALGORITHM_RIGHT_ASYMMETRIC_6:
7689         case ALGORITHM_LEFT_SYMMETRIC_6:
7690         case ALGORITHM_RIGHT_SYMMETRIC_6:
7691                 if (raid_disk == raid_disks - 1)
7692                         return 1;
7693         }
7694         return 0;
7695 }
7696
7697 static void raid5_set_io_opt(struct r5conf *conf)
7698 {
7699         blk_queue_io_opt(conf->mddev->queue, (conf->chunk_sectors << 9) *
7700                          (conf->raid_disks - conf->max_degraded));
7701 }
7702
7703 static int raid5_run(struct mddev *mddev)
7704 {
7705         struct r5conf *conf;
7706         int working_disks = 0;
7707         int dirty_parity_disks = 0;
7708         struct md_rdev *rdev;
7709         struct md_rdev *journal_dev = NULL;
7710         sector_t reshape_offset = 0;
7711         int i, ret = 0;
7712         long long min_offset_diff = 0;
7713         int first = 1;
7714
7715         if (acct_bioset_init(mddev)) {
7716                 pr_err("md/raid456:%s: alloc acct bioset failed.\n", mdname(mddev));
7717                 return -ENOMEM;
7718         }
7719
7720         if (mddev_init_writes_pending(mddev) < 0) {
7721                 ret = -ENOMEM;
7722                 goto exit_acct_set;
7723         }
7724
7725         if (mddev->recovery_cp != MaxSector)
7726                 pr_notice("md/raid:%s: not clean -- starting background reconstruction\n",
7727                           mdname(mddev));
7728
7729         rdev_for_each(rdev, mddev) {
7730                 long long diff;
7731
7732                 if (test_bit(Journal, &rdev->flags)) {
7733                         journal_dev = rdev;
7734                         continue;
7735                 }
7736                 if (rdev->raid_disk < 0)
7737                         continue;
7738                 diff = (rdev->new_data_offset - rdev->data_offset);
7739                 if (first) {
7740                         min_offset_diff = diff;
7741                         first = 0;
7742                 } else if (mddev->reshape_backwards &&
7743                          diff < min_offset_diff)
7744                         min_offset_diff = diff;
7745                 else if (!mddev->reshape_backwards &&
7746                          diff > min_offset_diff)
7747                         min_offset_diff = diff;
7748         }
7749
7750         if ((test_bit(MD_HAS_JOURNAL, &mddev->flags) || journal_dev) &&
7751             (mddev->bitmap_info.offset || mddev->bitmap_info.file)) {
7752                 pr_notice("md/raid:%s: array cannot have both journal and bitmap\n",
7753                           mdname(mddev));
7754                 ret = -EINVAL;
7755                 goto exit_acct_set;
7756         }
7757
7758         if (mddev->reshape_position != MaxSector) {
7759                 /* Check that we can continue the reshape.
7760                  * Difficulties arise if the stripe we would write to
7761                  * next is at or after the stripe we would read from next.
7762                  * For a reshape that changes the number of devices, this
7763                  * is only possible for a very short time, and mdadm makes
7764                  * sure that time appears to have past before assembling
7765                  * the array.  So we fail if that time hasn't passed.
7766                  * For a reshape that keeps the number of devices the same
7767                  * mdadm must be monitoring the reshape can keeping the
7768                  * critical areas read-only and backed up.  It will start
7769                  * the array in read-only mode, so we check for that.
7770                  */
7771                 sector_t here_new, here_old;
7772                 int old_disks;
7773                 int max_degraded = (mddev->level == 6 ? 2 : 1);
7774                 int chunk_sectors;
7775                 int new_data_disks;
7776
7777                 if (journal_dev) {
7778                         pr_warn("md/raid:%s: don't support reshape with journal - aborting.\n",
7779                                 mdname(mddev));
7780                         ret = -EINVAL;
7781                         goto exit_acct_set;
7782                 }
7783
7784                 if (mddev->new_level != mddev->level) {
7785                         pr_warn("md/raid:%s: unsupported reshape required - aborting.\n",
7786                                 mdname(mddev));
7787                         ret = -EINVAL;
7788                         goto exit_acct_set;
7789                 }
7790                 old_disks = mddev->raid_disks - mddev->delta_disks;
7791                 /* reshape_position must be on a new-stripe boundary, and one
7792                  * further up in new geometry must map after here in old
7793                  * geometry.
7794                  * If the chunk sizes are different, then as we perform reshape
7795                  * in units of the largest of the two, reshape_position needs
7796                  * be a multiple of the largest chunk size times new data disks.
7797                  */
7798                 here_new = mddev->reshape_position;
7799                 chunk_sectors = max(mddev->chunk_sectors, mddev->new_chunk_sectors);
7800                 new_data_disks = mddev->raid_disks - max_degraded;
7801                 if (sector_div(here_new, chunk_sectors * new_data_disks)) {
7802                         pr_warn("md/raid:%s: reshape_position not on a stripe boundary\n",
7803                                 mdname(mddev));
7804                         ret = -EINVAL;
7805                         goto exit_acct_set;
7806                 }
7807                 reshape_offset = here_new * chunk_sectors;
7808                 /* here_new is the stripe we will write to */
7809                 here_old = mddev->reshape_position;
7810                 sector_div(here_old, chunk_sectors * (old_disks-max_degraded));
7811                 /* here_old is the first stripe that we might need to read
7812                  * from */
7813                 if (mddev->delta_disks == 0) {
7814                         /* We cannot be sure it is safe to start an in-place
7815                          * reshape.  It is only safe if user-space is monitoring
7816                          * and taking constant backups.
7817                          * mdadm always starts a situation like this in
7818                          * readonly mode so it can take control before
7819                          * allowing any writes.  So just check for that.
7820                          */
7821                         if (abs(min_offset_diff) >= mddev->chunk_sectors &&
7822                             abs(min_offset_diff) >= mddev->new_chunk_sectors)
7823                                 /* not really in-place - so OK */;
7824                         else if (mddev->ro == 0) {
7825                                 pr_warn("md/raid:%s: in-place reshape must be started in read-only mode - aborting\n",
7826                                         mdname(mddev));
7827                                 ret = -EINVAL;
7828                                 goto exit_acct_set;
7829                         }
7830                 } else if (mddev->reshape_backwards
7831                     ? (here_new * chunk_sectors + min_offset_diff <=
7832                        here_old * chunk_sectors)
7833                     : (here_new * chunk_sectors >=
7834                        here_old * chunk_sectors + (-min_offset_diff))) {
7835                         /* Reading from the same stripe as writing to - bad */
7836                         pr_warn("md/raid:%s: reshape_position too early for auto-recovery - aborting.\n",
7837                                 mdname(mddev));
7838                         ret = -EINVAL;
7839                         goto exit_acct_set;
7840                 }
7841                 pr_debug("md/raid:%s: reshape will continue\n", mdname(mddev));
7842                 /* OK, we should be able to continue; */
7843         } else {
7844                 BUG_ON(mddev->level != mddev->new_level);
7845                 BUG_ON(mddev->layout != mddev->new_layout);
7846                 BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
7847                 BUG_ON(mddev->delta_disks != 0);
7848         }
7849
7850         if (test_bit(MD_HAS_JOURNAL, &mddev->flags) &&
7851             test_bit(MD_HAS_PPL, &mddev->flags)) {
7852                 pr_warn("md/raid:%s: using journal device and PPL not allowed - disabling PPL\n",
7853                         mdname(mddev));
7854                 clear_bit(MD_HAS_PPL, &mddev->flags);
7855                 clear_bit(MD_HAS_MULTIPLE_PPLS, &mddev->flags);
7856         }
7857
7858         if (mddev->private == NULL)
7859                 conf = setup_conf(mddev);
7860         else
7861                 conf = mddev->private;
7862
7863         if (IS_ERR(conf)) {
7864                 ret = PTR_ERR(conf);
7865                 goto exit_acct_set;
7866         }
7867
7868         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
7869                 if (!journal_dev) {
7870                         pr_warn("md/raid:%s: journal disk is missing, force array readonly\n",
7871                                 mdname(mddev));
7872                         mddev->ro = 1;
7873                         set_disk_ro(mddev->gendisk, 1);
7874                 } else if (mddev->recovery_cp == MaxSector)
7875                         set_bit(MD_JOURNAL_CLEAN, &mddev->flags);
7876         }
7877
7878         conf->min_offset_diff = min_offset_diff;
7879         mddev->thread = conf->thread;
7880         conf->thread = NULL;
7881         mddev->private = conf;
7882
7883         for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
7884              i++) {
7885                 rdev = rdev_mdlock_deref(mddev, conf->disks[i].rdev);
7886                 if (!rdev && conf->disks[i].replacement) {
7887                         /* The replacement is all we have yet */
7888                         rdev = rdev_mdlock_deref(mddev,
7889                                                  conf->disks[i].replacement);
7890                         conf->disks[i].replacement = NULL;
7891                         clear_bit(Replacement, &rdev->flags);
7892                         rcu_assign_pointer(conf->disks[i].rdev, rdev);
7893                 }
7894                 if (!rdev)
7895                         continue;
7896                 if (rcu_access_pointer(conf->disks[i].replacement) &&
7897                     conf->reshape_progress != MaxSector) {
7898                         /* replacements and reshape simply do not mix. */
7899                         pr_warn("md: cannot handle concurrent replacement and reshape.\n");
7900                         goto abort;
7901                 }
7902                 if (test_bit(In_sync, &rdev->flags)) {
7903                         working_disks++;
7904                         continue;
7905                 }
7906                 /* This disc is not fully in-sync.  However if it
7907                  * just stored parity (beyond the recovery_offset),
7908                  * when we don't need to be concerned about the
7909                  * array being dirty.
7910                  * When reshape goes 'backwards', we never have
7911                  * partially completed devices, so we only need
7912                  * to worry about reshape going forwards.
7913                  */
7914                 /* Hack because v0.91 doesn't store recovery_offset properly. */
7915                 if (mddev->major_version == 0 &&
7916                     mddev->minor_version > 90)
7917                         rdev->recovery_offset = reshape_offset;
7918
7919                 if (rdev->recovery_offset < reshape_offset) {
7920                         /* We need to check old and new layout */
7921                         if (!only_parity(rdev->raid_disk,
7922                                          conf->algorithm,
7923                                          conf->raid_disks,
7924                                          conf->max_degraded))
7925                                 continue;
7926                 }
7927                 if (!only_parity(rdev->raid_disk,
7928                                  conf->prev_algo,
7929                                  conf->previous_raid_disks,
7930                                  conf->max_degraded))
7931                         continue;
7932                 dirty_parity_disks++;
7933         }
7934
7935         /*
7936          * 0 for a fully functional array, 1 or 2 for a degraded array.
7937          */
7938         mddev->degraded = raid5_calc_degraded(conf);
7939
7940         if (has_failed(conf)) {
7941                 pr_crit("md/raid:%s: not enough operational devices (%d/%d failed)\n",
7942                         mdname(mddev), mddev->degraded, conf->raid_disks);
7943                 goto abort;
7944         }
7945
7946         /* device size must be a multiple of chunk size */
7947         mddev->dev_sectors &= ~((sector_t)mddev->chunk_sectors - 1);
7948         mddev->resync_max_sectors = mddev->dev_sectors;
7949
7950         if (mddev->degraded > dirty_parity_disks &&
7951             mddev->recovery_cp != MaxSector) {
7952                 if (test_bit(MD_HAS_PPL, &mddev->flags))
7953                         pr_crit("md/raid:%s: starting dirty degraded array with PPL.\n",
7954                                 mdname(mddev));
7955                 else if (mddev->ok_start_degraded)
7956                         pr_crit("md/raid:%s: starting dirty degraded array - data corruption possible.\n",
7957                                 mdname(mddev));
7958                 else {
7959                         pr_crit("md/raid:%s: cannot start dirty degraded array.\n",
7960                                 mdname(mddev));
7961                         goto abort;
7962                 }
7963         }
7964
7965         pr_info("md/raid:%s: raid level %d active with %d out of %d devices, algorithm %d\n",
7966                 mdname(mddev), conf->level,
7967                 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
7968                 mddev->new_layout);
7969
7970         print_raid5_conf(conf);
7971
7972         if (conf->reshape_progress != MaxSector) {
7973                 conf->reshape_safe = conf->reshape_progress;
7974                 atomic_set(&conf->reshape_stripes, 0);
7975                 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7976                 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7977                 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7978                 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7979                 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7980                                                         "reshape");
7981                 if (!mddev->sync_thread)
7982                         goto abort;
7983         }
7984
7985         /* Ok, everything is just fine now */
7986         if (mddev->to_remove == &raid5_attrs_group)
7987                 mddev->to_remove = NULL;
7988         else if (mddev->kobj.sd &&
7989             sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
7990                 pr_warn("raid5: failed to create sysfs attributes for %s\n",
7991                         mdname(mddev));
7992         md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
7993
7994         if (mddev->queue) {
7995                 int chunk_size;
7996                 /* read-ahead size must cover two whole stripes, which
7997                  * is 2 * (datadisks) * chunksize where 'n' is the
7998                  * number of raid devices
7999                  */
8000                 int data_disks = conf->previous_raid_disks - conf->max_degraded;
8001                 int stripe = data_disks *
8002                         ((mddev->chunk_sectors << 9) / PAGE_SIZE);
8003
8004                 chunk_size = mddev->chunk_sectors << 9;
8005                 blk_queue_io_min(mddev->queue, chunk_size);
8006                 raid5_set_io_opt(conf);
8007                 mddev->queue->limits.raid_partial_stripes_expensive = 1;
8008                 /*
8009                  * We can only discard a whole stripe. It doesn't make sense to
8010                  * discard data disk but write parity disk
8011                  */
8012                 stripe = stripe * PAGE_SIZE;
8013                 stripe = roundup_pow_of_two(stripe);
8014                 mddev->queue->limits.discard_granularity = stripe;
8015
8016                 blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
8017
8018                 rdev_for_each(rdev, mddev) {
8019                         disk_stack_limits(mddev->gendisk, rdev->bdev,
8020                                           rdev->data_offset << 9);
8021                         disk_stack_limits(mddev->gendisk, rdev->bdev,
8022                                           rdev->new_data_offset << 9);
8023                 }
8024
8025                 /*
8026                  * zeroing is required, otherwise data
8027                  * could be lost. Consider a scenario: discard a stripe
8028                  * (the stripe could be inconsistent if
8029                  * discard_zeroes_data is 0); write one disk of the
8030                  * stripe (the stripe could be inconsistent again
8031                  * depending on which disks are used to calculate
8032                  * parity); the disk is broken; The stripe data of this
8033                  * disk is lost.
8034                  *
8035                  * We only allow DISCARD if the sysadmin has confirmed that
8036                  * only safe devices are in use by setting a module parameter.
8037                  * A better idea might be to turn DISCARD into WRITE_ZEROES
8038                  * requests, as that is required to be safe.
8039                  */
8040                 if (!devices_handle_discard_safely ||
8041                     mddev->queue->limits.max_discard_sectors < (stripe >> 9) ||
8042                     mddev->queue->limits.discard_granularity < stripe)
8043                         blk_queue_max_discard_sectors(mddev->queue, 0);
8044
8045                 /*
8046                  * Requests require having a bitmap for each stripe.
8047                  * Limit the max sectors based on this.
8048                  */
8049                 blk_queue_max_hw_sectors(mddev->queue,
8050                         RAID5_MAX_REQ_STRIPES << RAID5_STRIPE_SHIFT(conf));
8051
8052                 /* No restrictions on the number of segments in the request */
8053                 blk_queue_max_segments(mddev->queue, USHRT_MAX);
8054         }
8055
8056         if (log_init(conf, journal_dev, raid5_has_ppl(conf)))
8057                 goto abort;
8058
8059         return 0;
8060 abort:
8061         md_unregister_thread(&mddev->thread);
8062         print_raid5_conf(conf);
8063         free_conf(conf);
8064         mddev->private = NULL;
8065         pr_warn("md/raid:%s: failed to run raid set.\n", mdname(mddev));
8066         ret = -EIO;
8067 exit_acct_set:
8068         acct_bioset_exit(mddev);
8069         return ret;
8070 }
8071
8072 static void raid5_free(struct mddev *mddev, void *priv)
8073 {
8074         struct r5conf *conf = priv;
8075
8076         free_conf(conf);
8077         acct_bioset_exit(mddev);
8078         mddev->to_remove = &raid5_attrs_group;
8079 }
8080
8081 static void raid5_status(struct seq_file *seq, struct mddev *mddev)
8082 {
8083         struct r5conf *conf = mddev->private;
8084         int i;
8085
8086         seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
8087                 conf->chunk_sectors / 2, mddev->layout);
8088         seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
8089         rcu_read_lock();
8090         for (i = 0; i < conf->raid_disks; i++) {
8091                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
8092                 seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
8093         }
8094         rcu_read_unlock();
8095         seq_printf (seq, "]");
8096 }
8097
8098 static void print_raid5_conf (struct r5conf *conf)
8099 {
8100         struct md_rdev *rdev;
8101         int i;
8102
8103         pr_debug("RAID conf printout:\n");
8104         if (!conf) {
8105                 pr_debug("(conf==NULL)\n");
8106                 return;
8107         }
8108         pr_debug(" --- level:%d rd:%d wd:%d\n", conf->level,
8109                conf->raid_disks,
8110                conf->raid_disks - conf->mddev->degraded);
8111
8112         rcu_read_lock();
8113         for (i = 0; i < conf->raid_disks; i++) {
8114                 rdev = rcu_dereference(conf->disks[i].rdev);
8115                 if (rdev)
8116                         pr_debug(" disk %d, o:%d, dev:%pg\n",
8117                                i, !test_bit(Faulty, &rdev->flags),
8118                                rdev->bdev);
8119         }
8120         rcu_read_unlock();
8121 }
8122
8123 static int raid5_spare_active(struct mddev *mddev)
8124 {
8125         int i;
8126         struct r5conf *conf = mddev->private;
8127         struct md_rdev *rdev, *replacement;
8128         int count = 0;
8129         unsigned long flags;
8130
8131         for (i = 0; i < conf->raid_disks; i++) {
8132                 rdev = rdev_mdlock_deref(mddev, conf->disks[i].rdev);
8133                 replacement = rdev_mdlock_deref(mddev,
8134                                                 conf->disks[i].replacement);
8135                 if (replacement
8136                     && replacement->recovery_offset == MaxSector
8137                     && !test_bit(Faulty, &replacement->flags)
8138                     && !test_and_set_bit(In_sync, &replacement->flags)) {
8139                         /* Replacement has just become active. */
8140                         if (!rdev
8141                             || !test_and_clear_bit(In_sync, &rdev->flags))
8142                                 count++;
8143                         if (rdev) {
8144                                 /* Replaced device not technically faulty,
8145                                  * but we need to be sure it gets removed
8146                                  * and never re-added.
8147                                  */
8148                                 set_bit(Faulty, &rdev->flags);
8149                                 sysfs_notify_dirent_safe(
8150                                         rdev->sysfs_state);
8151                         }
8152                         sysfs_notify_dirent_safe(replacement->sysfs_state);
8153                 } else if (rdev
8154                     && rdev->recovery_offset == MaxSector
8155                     && !test_bit(Faulty, &rdev->flags)
8156                     && !test_and_set_bit(In_sync, &rdev->flags)) {
8157                         count++;
8158                         sysfs_notify_dirent_safe(rdev->sysfs_state);
8159                 }
8160         }
8161         spin_lock_irqsave(&conf->device_lock, flags);
8162         mddev->degraded = raid5_calc_degraded(conf);
8163         spin_unlock_irqrestore(&conf->device_lock, flags);
8164         print_raid5_conf(conf);
8165         return count;
8166 }
8167
8168 static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
8169 {
8170         struct r5conf *conf = mddev->private;
8171         int err = 0;
8172         int number = rdev->raid_disk;
8173         struct md_rdev __rcu **rdevp;
8174         struct disk_info *p;
8175         struct md_rdev *tmp;
8176
8177         print_raid5_conf(conf);
8178         if (test_bit(Journal, &rdev->flags) && conf->log) {
8179                 /*
8180                  * we can't wait pending write here, as this is called in
8181                  * raid5d, wait will deadlock.
8182                  * neilb: there is no locking about new writes here,
8183                  * so this cannot be safe.
8184                  */
8185                 if (atomic_read(&conf->active_stripes) ||
8186                     atomic_read(&conf->r5c_cached_full_stripes) ||
8187                     atomic_read(&conf->r5c_cached_partial_stripes)) {
8188                         return -EBUSY;
8189                 }
8190                 log_exit(conf);
8191                 return 0;
8192         }
8193         if (unlikely(number >= conf->pool_size))
8194                 return 0;
8195         p = conf->disks + number;
8196         if (rdev == rcu_access_pointer(p->rdev))
8197                 rdevp = &p->rdev;
8198         else if (rdev == rcu_access_pointer(p->replacement))
8199                 rdevp = &p->replacement;
8200         else
8201                 return 0;
8202
8203         if (number >= conf->raid_disks &&
8204             conf->reshape_progress == MaxSector)
8205                 clear_bit(In_sync, &rdev->flags);
8206
8207         if (test_bit(In_sync, &rdev->flags) ||
8208             atomic_read(&rdev->nr_pending)) {
8209                 err = -EBUSY;
8210                 goto abort;
8211         }
8212         /* Only remove non-faulty devices if recovery
8213          * isn't possible.
8214          */
8215         if (!test_bit(Faulty, &rdev->flags) &&
8216             mddev->recovery_disabled != conf->recovery_disabled &&
8217             !has_failed(conf) &&
8218             (!rcu_access_pointer(p->replacement) ||
8219              rcu_access_pointer(p->replacement) == rdev) &&
8220             number < conf->raid_disks) {
8221                 err = -EBUSY;
8222                 goto abort;
8223         }
8224         *rdevp = NULL;
8225         if (!test_bit(RemoveSynchronized, &rdev->flags)) {
8226                 lockdep_assert_held(&mddev->reconfig_mutex);
8227                 synchronize_rcu();
8228                 if (atomic_read(&rdev->nr_pending)) {
8229                         /* lost the race, try later */
8230                         err = -EBUSY;
8231                         rcu_assign_pointer(*rdevp, rdev);
8232                 }
8233         }
8234         if (!err) {
8235                 err = log_modify(conf, rdev, false);
8236                 if (err)
8237                         goto abort;
8238         }
8239
8240         tmp = rcu_access_pointer(p->replacement);
8241         if (tmp) {
8242                 /* We must have just cleared 'rdev' */
8243                 rcu_assign_pointer(p->rdev, tmp);
8244                 clear_bit(Replacement, &tmp->flags);
8245                 smp_mb(); /* Make sure other CPUs may see both as identical
8246                            * but will never see neither - if they are careful
8247                            */
8248                 rcu_assign_pointer(p->replacement, NULL);
8249
8250                 if (!err)
8251                         err = log_modify(conf, tmp, true);
8252         }
8253
8254         clear_bit(WantReplacement, &rdev->flags);
8255 abort:
8256
8257         print_raid5_conf(conf);
8258         return err;
8259 }
8260
8261 static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
8262 {
8263         struct r5conf *conf = mddev->private;
8264         int ret, err = -EEXIST;
8265         int disk;
8266         struct disk_info *p;
8267         struct md_rdev *tmp;
8268         int first = 0;
8269         int last = conf->raid_disks - 1;
8270
8271         if (test_bit(Journal, &rdev->flags)) {
8272                 if (conf->log)
8273                         return -EBUSY;
8274
8275                 rdev->raid_disk = 0;
8276                 /*
8277                  * The array is in readonly mode if journal is missing, so no
8278                  * write requests running. We should be safe
8279                  */
8280                 ret = log_init(conf, rdev, false);
8281                 if (ret)
8282                         return ret;
8283
8284                 ret = r5l_start(conf->log);
8285                 if (ret)
8286                         return ret;
8287
8288                 return 0;
8289         }
8290         if (mddev->recovery_disabled == conf->recovery_disabled)
8291                 return -EBUSY;
8292
8293         if (rdev->saved_raid_disk < 0 && has_failed(conf))
8294                 /* no point adding a device */
8295                 return -EINVAL;
8296
8297         if (rdev->raid_disk >= 0)
8298                 first = last = rdev->raid_disk;
8299
8300         /*
8301          * find the disk ... but prefer rdev->saved_raid_disk
8302          * if possible.
8303          */
8304         if (rdev->saved_raid_disk >= first &&
8305             rdev->saved_raid_disk <= last &&
8306             conf->disks[rdev->saved_raid_disk].rdev == NULL)
8307                 first = rdev->saved_raid_disk;
8308
8309         for (disk = first; disk <= last; disk++) {
8310                 p = conf->disks + disk;
8311                 if (p->rdev == NULL) {
8312                         clear_bit(In_sync, &rdev->flags);
8313                         rdev->raid_disk = disk;
8314                         if (rdev->saved_raid_disk != disk)
8315                                 conf->fullsync = 1;
8316                         rcu_assign_pointer(p->rdev, rdev);
8317
8318                         err = log_modify(conf, rdev, true);
8319
8320                         goto out;
8321                 }
8322         }
8323         for (disk = first; disk <= last; disk++) {
8324                 p = conf->disks + disk;
8325                 tmp = rdev_mdlock_deref(mddev, p->rdev);
8326                 if (test_bit(WantReplacement, &tmp->flags) &&
8327                     p->replacement == NULL) {
8328                         clear_bit(In_sync, &rdev->flags);
8329                         set_bit(Replacement, &rdev->flags);
8330                         rdev->raid_disk = disk;
8331                         err = 0;
8332                         conf->fullsync = 1;
8333                         rcu_assign_pointer(p->replacement, rdev);
8334                         break;
8335                 }
8336         }
8337 out:
8338         print_raid5_conf(conf);
8339         return err;
8340 }
8341
8342 static int raid5_resize(struct mddev *mddev, sector_t sectors)
8343 {
8344         /* no resync is happening, and there is enough space
8345          * on all devices, so we can resize.
8346          * We need to make sure resync covers any new space.
8347          * If the array is shrinking we should possibly wait until
8348          * any io in the removed space completes, but it hardly seems
8349          * worth it.
8350          */
8351         sector_t newsize;
8352         struct r5conf *conf = mddev->private;
8353
8354         if (raid5_has_log(conf) || raid5_has_ppl(conf))
8355                 return -EINVAL;
8356         sectors &= ~((sector_t)conf->chunk_sectors - 1);
8357         newsize = raid5_size(mddev, sectors, mddev->raid_disks);
8358         if (mddev->external_size &&
8359             mddev->array_sectors > newsize)
8360                 return -EINVAL;
8361         if (mddev->bitmap) {
8362                 int ret = md_bitmap_resize(mddev->bitmap, sectors, 0, 0);
8363                 if (ret)
8364                         return ret;
8365         }
8366         md_set_array_sectors(mddev, newsize);
8367         if (sectors > mddev->dev_sectors &&
8368             mddev->recovery_cp > mddev->dev_sectors) {
8369                 mddev->recovery_cp = mddev->dev_sectors;
8370                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
8371         }
8372         mddev->dev_sectors = sectors;
8373         mddev->resync_max_sectors = sectors;
8374         return 0;
8375 }
8376
8377 static int check_stripe_cache(struct mddev *mddev)
8378 {
8379         /* Can only proceed if there are plenty of stripe_heads.
8380          * We need a minimum of one full stripe,, and for sensible progress
8381          * it is best to have about 4 times that.
8382          * If we require 4 times, then the default 256 4K stripe_heads will
8383          * allow for chunk sizes up to 256K, which is probably OK.
8384          * If the chunk size is greater, user-space should request more
8385          * stripe_heads first.
8386          */
8387         struct r5conf *conf = mddev->private;
8388         if (((mddev->chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4
8389             > conf->min_nr_stripes ||
8390             ((mddev->new_chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4
8391             > conf->min_nr_stripes) {
8392                 pr_warn("md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
8393                         mdname(mddev),
8394                         ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
8395                          / RAID5_STRIPE_SIZE(conf))*4);
8396                 return 0;
8397         }
8398         return 1;
8399 }
8400
8401 static int check_reshape(struct mddev *mddev)
8402 {
8403         struct r5conf *conf = mddev->private;
8404
8405         if (raid5_has_log(conf) || raid5_has_ppl(conf))
8406                 return -EINVAL;
8407         if (mddev->delta_disks == 0 &&
8408             mddev->new_layout == mddev->layout &&
8409             mddev->new_chunk_sectors == mddev->chunk_sectors)
8410                 return 0; /* nothing to do */
8411         if (has_failed(conf))
8412                 return -EINVAL;
8413         if (mddev->delta_disks < 0 && mddev->reshape_position == MaxSector) {
8414                 /* We might be able to shrink, but the devices must
8415                  * be made bigger first.
8416                  * For raid6, 4 is the minimum size.
8417                  * Otherwise 2 is the minimum
8418                  */
8419                 int min = 2;
8420                 if (mddev->level == 6)
8421                         min = 4;
8422                 if (mddev->raid_disks + mddev->delta_disks < min)
8423                         return -EINVAL;
8424         }
8425
8426         if (!check_stripe_cache(mddev))
8427                 return -ENOSPC;
8428
8429         if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
8430             mddev->delta_disks > 0)
8431                 if (resize_chunks(conf,
8432                                   conf->previous_raid_disks
8433                                   + max(0, mddev->delta_disks),
8434                                   max(mddev->new_chunk_sectors,
8435                                       mddev->chunk_sectors)
8436                             ) < 0)
8437                         return -ENOMEM;
8438
8439         if (conf->previous_raid_disks + mddev->delta_disks <= conf->pool_size)
8440                 return 0; /* never bother to shrink */
8441         return resize_stripes(conf, (conf->previous_raid_disks
8442                                      + mddev->delta_disks));
8443 }
8444
8445 static int raid5_start_reshape(struct mddev *mddev)
8446 {
8447         struct r5conf *conf = mddev->private;
8448         struct md_rdev *rdev;
8449         int spares = 0;
8450         unsigned long flags;
8451
8452         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
8453                 return -EBUSY;
8454
8455         if (!check_stripe_cache(mddev))
8456                 return -ENOSPC;
8457
8458         if (has_failed(conf))
8459                 return -EINVAL;
8460
8461         rdev_for_each(rdev, mddev) {
8462                 if (!test_bit(In_sync, &rdev->flags)
8463                     && !test_bit(Faulty, &rdev->flags))
8464                         spares++;
8465         }
8466
8467         if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
8468                 /* Not enough devices even to make a degraded array
8469                  * of that size
8470                  */
8471                 return -EINVAL;
8472
8473         /* Refuse to reduce size of the array.  Any reductions in
8474          * array size must be through explicit setting of array_size
8475          * attribute.
8476          */
8477         if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
8478             < mddev->array_sectors) {
8479                 pr_warn("md/raid:%s: array size must be reduced before number of disks\n",
8480                         mdname(mddev));
8481                 return -EINVAL;
8482         }
8483
8484         atomic_set(&conf->reshape_stripes, 0);
8485         spin_lock_irq(&conf->device_lock);
8486         write_seqcount_begin(&conf->gen_lock);
8487         conf->previous_raid_disks = conf->raid_disks;
8488         conf->raid_disks += mddev->delta_disks;
8489         conf->prev_chunk_sectors = conf->chunk_sectors;
8490         conf->chunk_sectors = mddev->new_chunk_sectors;
8491         conf->prev_algo = conf->algorithm;
8492         conf->algorithm = mddev->new_layout;
8493         conf->generation++;
8494         /* Code that selects data_offset needs to see the generation update
8495          * if reshape_progress has been set - so a memory barrier needed.
8496          */
8497         smp_mb();
8498         if (mddev->reshape_backwards)
8499                 conf->reshape_progress = raid5_size(mddev, 0, 0);
8500         else
8501                 conf->reshape_progress = 0;
8502         conf->reshape_safe = conf->reshape_progress;
8503         write_seqcount_end(&conf->gen_lock);
8504         spin_unlock_irq(&conf->device_lock);
8505
8506         /* Now make sure any requests that proceeded on the assumption
8507          * the reshape wasn't running - like Discard or Read - have
8508          * completed.
8509          */
8510         mddev_suspend(mddev);
8511         mddev_resume(mddev);
8512
8513         /* Add some new drives, as many as will fit.
8514          * We know there are enough to make the newly sized array work.
8515          * Don't add devices if we are reducing the number of
8516          * devices in the array.  This is because it is not possible
8517          * to correctly record the "partially reconstructed" state of
8518          * such devices during the reshape and confusion could result.
8519          */
8520         if (mddev->delta_disks >= 0) {
8521                 rdev_for_each(rdev, mddev)
8522                         if (rdev->raid_disk < 0 &&
8523                             !test_bit(Faulty, &rdev->flags)) {
8524                                 if (raid5_add_disk(mddev, rdev) == 0) {
8525                                         if (rdev->raid_disk
8526                                             >= conf->previous_raid_disks)
8527                                                 set_bit(In_sync, &rdev->flags);
8528                                         else
8529                                                 rdev->recovery_offset = 0;
8530
8531                                         /* Failure here is OK */
8532                                         sysfs_link_rdev(mddev, rdev);
8533                                 }
8534                         } else if (rdev->raid_disk >= conf->previous_raid_disks
8535                                    && !test_bit(Faulty, &rdev->flags)) {
8536                                 /* This is a spare that was manually added */
8537                                 set_bit(In_sync, &rdev->flags);
8538                         }
8539
8540                 /* When a reshape changes the number of devices,
8541                  * ->degraded is measured against the larger of the
8542                  * pre and post number of devices.
8543                  */
8544                 spin_lock_irqsave(&conf->device_lock, flags);
8545                 mddev->degraded = raid5_calc_degraded(conf);
8546                 spin_unlock_irqrestore(&conf->device_lock, flags);
8547         }
8548         mddev->raid_disks = conf->raid_disks;
8549         mddev->reshape_position = conf->reshape_progress;
8550         set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8551
8552         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
8553         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
8554         clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
8555         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
8556         set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
8557         mddev->sync_thread = md_register_thread(md_do_sync, mddev,
8558                                                 "reshape");
8559         if (!mddev->sync_thread) {
8560                 mddev->recovery = 0;
8561                 spin_lock_irq(&conf->device_lock);
8562                 write_seqcount_begin(&conf->gen_lock);
8563                 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
8564                 mddev->new_chunk_sectors =
8565                         conf->chunk_sectors = conf->prev_chunk_sectors;
8566                 mddev->new_layout = conf->algorithm = conf->prev_algo;
8567                 rdev_for_each(rdev, mddev)
8568                         rdev->new_data_offset = rdev->data_offset;
8569                 smp_wmb();
8570                 conf->generation --;
8571                 conf->reshape_progress = MaxSector;
8572                 mddev->reshape_position = MaxSector;
8573                 write_seqcount_end(&conf->gen_lock);
8574                 spin_unlock_irq(&conf->device_lock);
8575                 return -EAGAIN;
8576         }
8577         conf->reshape_checkpoint = jiffies;
8578         md_wakeup_thread(mddev->sync_thread);
8579         md_new_event();
8580         return 0;
8581 }
8582
8583 /* This is called from the reshape thread and should make any
8584  * changes needed in 'conf'
8585  */
8586 static void end_reshape(struct r5conf *conf)
8587 {
8588
8589         if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
8590                 struct md_rdev *rdev;
8591
8592                 spin_lock_irq(&conf->device_lock);
8593                 conf->previous_raid_disks = conf->raid_disks;
8594                 md_finish_reshape(conf->mddev);
8595                 smp_wmb();
8596                 conf->reshape_progress = MaxSector;
8597                 conf->mddev->reshape_position = MaxSector;
8598                 rdev_for_each(rdev, conf->mddev)
8599                         if (rdev->raid_disk >= 0 &&
8600                             !test_bit(Journal, &rdev->flags) &&
8601                             !test_bit(In_sync, &rdev->flags))
8602                                 rdev->recovery_offset = MaxSector;
8603                 spin_unlock_irq(&conf->device_lock);
8604                 wake_up(&conf->wait_for_overlap);
8605
8606                 if (conf->mddev->queue)
8607                         raid5_set_io_opt(conf);
8608         }
8609 }
8610
8611 /* This is called from the raid5d thread with mddev_lock held.
8612  * It makes config changes to the device.
8613  */
8614 static void raid5_finish_reshape(struct mddev *mddev)
8615 {
8616         struct r5conf *conf = mddev->private;
8617         struct md_rdev *rdev;
8618
8619         if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
8620
8621                 if (mddev->delta_disks <= 0) {
8622                         int d;
8623                         spin_lock_irq(&conf->device_lock);
8624                         mddev->degraded = raid5_calc_degraded(conf);
8625                         spin_unlock_irq(&conf->device_lock);
8626                         for (d = conf->raid_disks ;
8627                              d < conf->raid_disks - mddev->delta_disks;
8628                              d++) {
8629                                 rdev = rdev_mdlock_deref(mddev,
8630                                                          conf->disks[d].rdev);
8631                                 if (rdev)
8632                                         clear_bit(In_sync, &rdev->flags);
8633                                 rdev = rdev_mdlock_deref(mddev,
8634                                                 conf->disks[d].replacement);
8635                                 if (rdev)
8636                                         clear_bit(In_sync, &rdev->flags);
8637                         }
8638                 }
8639                 mddev->layout = conf->algorithm;
8640                 mddev->chunk_sectors = conf->chunk_sectors;
8641                 mddev->reshape_position = MaxSector;
8642                 mddev->delta_disks = 0;
8643                 mddev->reshape_backwards = 0;
8644         }
8645 }
8646
8647 static void raid5_quiesce(struct mddev *mddev, int quiesce)
8648 {
8649         struct r5conf *conf = mddev->private;
8650
8651         if (quiesce) {
8652                 /* stop all writes */
8653                 lock_all_device_hash_locks_irq(conf);
8654                 /* '2' tells resync/reshape to pause so that all
8655                  * active stripes can drain
8656                  */
8657                 r5c_flush_cache(conf, INT_MAX);
8658                 /* need a memory barrier to make sure read_one_chunk() sees
8659                  * quiesce started and reverts to slow (locked) path.
8660                  */
8661                 smp_store_release(&conf->quiesce, 2);
8662                 wait_event_cmd(conf->wait_for_quiescent,
8663                                     atomic_read(&conf->active_stripes) == 0 &&
8664                                     atomic_read(&conf->active_aligned_reads) == 0,
8665                                     unlock_all_device_hash_locks_irq(conf),
8666                                     lock_all_device_hash_locks_irq(conf));
8667                 conf->quiesce = 1;
8668                 unlock_all_device_hash_locks_irq(conf);
8669                 /* allow reshape to continue */
8670                 wake_up(&conf->wait_for_overlap);
8671         } else {
8672                 /* re-enable writes */
8673                 lock_all_device_hash_locks_irq(conf);
8674                 conf->quiesce = 0;
8675                 wake_up(&conf->wait_for_quiescent);
8676                 wake_up(&conf->wait_for_overlap);
8677                 unlock_all_device_hash_locks_irq(conf);
8678         }
8679         log_quiesce(conf, quiesce);
8680 }
8681
8682 static void *raid45_takeover_raid0(struct mddev *mddev, int level)
8683 {
8684         struct r0conf *raid0_conf = mddev->private;
8685         sector_t sectors;
8686
8687         /* for raid0 takeover only one zone is supported */
8688         if (raid0_conf->nr_strip_zones > 1) {
8689                 pr_warn("md/raid:%s: cannot takeover raid0 with more than one zone.\n",
8690                         mdname(mddev));
8691                 return ERR_PTR(-EINVAL);
8692         }
8693
8694         sectors = raid0_conf->strip_zone[0].zone_end;
8695         sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
8696         mddev->dev_sectors = sectors;
8697         mddev->new_level = level;
8698         mddev->new_layout = ALGORITHM_PARITY_N;
8699         mddev->new_chunk_sectors = mddev->chunk_sectors;
8700         mddev->raid_disks += 1;
8701         mddev->delta_disks = 1;
8702         /* make sure it will be not marked as dirty */
8703         mddev->recovery_cp = MaxSector;
8704
8705         return setup_conf(mddev);
8706 }
8707
8708 static void *raid5_takeover_raid1(struct mddev *mddev)
8709 {
8710         int chunksect;
8711         void *ret;
8712
8713         if (mddev->raid_disks != 2 ||
8714             mddev->degraded > 1)
8715                 return ERR_PTR(-EINVAL);
8716
8717         /* Should check if there are write-behind devices? */
8718
8719         chunksect = 64*2; /* 64K by default */
8720
8721         /* The array must be an exact multiple of chunksize */
8722         while (chunksect && (mddev->array_sectors & (chunksect-1)))
8723                 chunksect >>= 1;
8724
8725         if ((chunksect<<9) < RAID5_STRIPE_SIZE((struct r5conf *)mddev->private))
8726                 /* array size does not allow a suitable chunk size */
8727                 return ERR_PTR(-EINVAL);
8728
8729         mddev->new_level = 5;
8730         mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
8731         mddev->new_chunk_sectors = chunksect;
8732
8733         ret = setup_conf(mddev);
8734         if (!IS_ERR(ret))
8735                 mddev_clear_unsupported_flags(mddev,
8736                         UNSUPPORTED_MDDEV_FLAGS);
8737         return ret;
8738 }
8739
8740 static void *raid5_takeover_raid6(struct mddev *mddev)
8741 {
8742         int new_layout;
8743
8744         switch (mddev->layout) {
8745         case ALGORITHM_LEFT_ASYMMETRIC_6:
8746                 new_layout = ALGORITHM_LEFT_ASYMMETRIC;
8747                 break;
8748         case ALGORITHM_RIGHT_ASYMMETRIC_6:
8749                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
8750                 break;
8751         case ALGORITHM_LEFT_SYMMETRIC_6:
8752                 new_layout = ALGORITHM_LEFT_SYMMETRIC;
8753                 break;
8754         case ALGORITHM_RIGHT_SYMMETRIC_6:
8755                 new_layout = ALGORITHM_RIGHT_SYMMETRIC;
8756                 break;
8757         case ALGORITHM_PARITY_0_6:
8758                 new_layout = ALGORITHM_PARITY_0;
8759                 break;
8760         case ALGORITHM_PARITY_N:
8761                 new_layout = ALGORITHM_PARITY_N;
8762                 break;
8763         default:
8764                 return ERR_PTR(-EINVAL);
8765         }
8766         mddev->new_level = 5;
8767         mddev->new_layout = new_layout;
8768         mddev->delta_disks = -1;
8769         mddev->raid_disks -= 1;
8770         return setup_conf(mddev);
8771 }
8772
8773 static int raid5_check_reshape(struct mddev *mddev)
8774 {
8775         /* For a 2-drive array, the layout and chunk size can be changed
8776          * immediately as not restriping is needed.
8777          * For larger arrays we record the new value - after validation
8778          * to be used by a reshape pass.
8779          */
8780         struct r5conf *conf = mddev->private;
8781         int new_chunk = mddev->new_chunk_sectors;
8782
8783         if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
8784                 return -EINVAL;
8785         if (new_chunk > 0) {
8786                 if (!is_power_of_2(new_chunk))
8787                         return -EINVAL;
8788                 if (new_chunk < (PAGE_SIZE>>9))
8789                         return -EINVAL;
8790                 if (mddev->array_sectors & (new_chunk-1))
8791                         /* not factor of array size */
8792                         return -EINVAL;
8793         }
8794
8795         /* They look valid */
8796
8797         if (mddev->raid_disks == 2) {
8798                 /* can make the change immediately */
8799                 if (mddev->new_layout >= 0) {
8800                         conf->algorithm = mddev->new_layout;
8801                         mddev->layout = mddev->new_layout;
8802                 }
8803                 if (new_chunk > 0) {
8804                         conf->chunk_sectors = new_chunk ;
8805                         mddev->chunk_sectors = new_chunk;
8806                 }
8807                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8808                 md_wakeup_thread(mddev->thread);
8809         }
8810         return check_reshape(mddev);
8811 }
8812
8813 static int raid6_check_reshape(struct mddev *mddev)
8814 {
8815         int new_chunk = mddev->new_chunk_sectors;
8816
8817         if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
8818                 return -EINVAL;
8819         if (new_chunk > 0) {
8820                 if (!is_power_of_2(new_chunk))
8821                         return -EINVAL;
8822                 if (new_chunk < (PAGE_SIZE >> 9))
8823                         return -EINVAL;
8824                 if (mddev->array_sectors & (new_chunk-1))
8825                         /* not factor of array size */
8826                         return -EINVAL;
8827         }
8828
8829         /* They look valid */
8830         return check_reshape(mddev);
8831 }
8832
8833 static void *raid5_takeover(struct mddev *mddev)
8834 {
8835         /* raid5 can take over:
8836          *  raid0 - if there is only one strip zone - make it a raid4 layout
8837          *  raid1 - if there are two drives.  We need to know the chunk size
8838          *  raid4 - trivial - just use a raid4 layout.
8839          *  raid6 - Providing it is a *_6 layout
8840          */
8841         if (mddev->level == 0)
8842                 return raid45_takeover_raid0(mddev, 5);
8843         if (mddev->level == 1)
8844                 return raid5_takeover_raid1(mddev);
8845         if (mddev->level == 4) {
8846                 mddev->new_layout = ALGORITHM_PARITY_N;
8847                 mddev->new_level = 5;
8848                 return setup_conf(mddev);
8849         }
8850         if (mddev->level == 6)
8851                 return raid5_takeover_raid6(mddev);
8852
8853         return ERR_PTR(-EINVAL);
8854 }
8855
8856 static void *raid4_takeover(struct mddev *mddev)
8857 {
8858         /* raid4 can take over:
8859          *  raid0 - if there is only one strip zone
8860          *  raid5 - if layout is right
8861          */
8862         if (mddev->level == 0)
8863                 return raid45_takeover_raid0(mddev, 4);
8864         if (mddev->level == 5 &&
8865             mddev->layout == ALGORITHM_PARITY_N) {
8866                 mddev->new_layout = 0;
8867                 mddev->new_level = 4;
8868                 return setup_conf(mddev);
8869         }
8870         return ERR_PTR(-EINVAL);
8871 }
8872
8873 static struct md_personality raid5_personality;
8874
8875 static void *raid6_takeover(struct mddev *mddev)
8876 {
8877         /* Currently can only take over a raid5.  We map the
8878          * personality to an equivalent raid6 personality
8879          * with the Q block at the end.
8880          */
8881         int new_layout;
8882
8883         if (mddev->pers != &raid5_personality)
8884                 return ERR_PTR(-EINVAL);
8885         if (mddev->degraded > 1)
8886                 return ERR_PTR(-EINVAL);
8887         if (mddev->raid_disks > 253)
8888                 return ERR_PTR(-EINVAL);
8889         if (mddev->raid_disks < 3)
8890                 return ERR_PTR(-EINVAL);
8891
8892         switch (mddev->layout) {
8893         case ALGORITHM_LEFT_ASYMMETRIC:
8894                 new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
8895                 break;
8896         case ALGORITHM_RIGHT_ASYMMETRIC:
8897                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
8898                 break;
8899         case ALGORITHM_LEFT_SYMMETRIC:
8900                 new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
8901                 break;
8902         case ALGORITHM_RIGHT_SYMMETRIC:
8903                 new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
8904                 break;
8905         case ALGORITHM_PARITY_0:
8906                 new_layout = ALGORITHM_PARITY_0_6;
8907                 break;
8908         case ALGORITHM_PARITY_N:
8909                 new_layout = ALGORITHM_PARITY_N;
8910                 break;
8911         default:
8912                 return ERR_PTR(-EINVAL);
8913         }
8914         mddev->new_level = 6;
8915         mddev->new_layout = new_layout;
8916         mddev->delta_disks = 1;
8917         mddev->raid_disks += 1;
8918         return setup_conf(mddev);
8919 }
8920
8921 static int raid5_change_consistency_policy(struct mddev *mddev, const char *buf)
8922 {
8923         struct r5conf *conf;
8924         int err;
8925
8926         err = mddev_lock(mddev);
8927         if (err)
8928                 return err;
8929         conf = mddev->private;
8930         if (!conf) {
8931                 mddev_unlock(mddev);
8932                 return -ENODEV;
8933         }
8934
8935         if (strncmp(buf, "ppl", 3) == 0) {
8936                 /* ppl only works with RAID 5 */
8937                 if (!raid5_has_ppl(conf) && conf->level == 5) {
8938                         err = log_init(conf, NULL, true);
8939                         if (!err) {
8940                                 err = resize_stripes(conf, conf->pool_size);
8941                                 if (err) {
8942                                         mddev_suspend(mddev);
8943                                         log_exit(conf);
8944                                         mddev_resume(mddev);
8945                                 }
8946                         }
8947                 } else
8948                         err = -EINVAL;
8949         } else if (strncmp(buf, "resync", 6) == 0) {
8950                 if (raid5_has_ppl(conf)) {
8951                         mddev_suspend(mddev);
8952                         log_exit(conf);
8953                         mddev_resume(mddev);
8954                         err = resize_stripes(conf, conf->pool_size);
8955                 } else if (test_bit(MD_HAS_JOURNAL, &conf->mddev->flags) &&
8956                            r5l_log_disk_error(conf)) {
8957                         bool journal_dev_exists = false;
8958                         struct md_rdev *rdev;
8959
8960                         rdev_for_each(rdev, mddev)
8961                                 if (test_bit(Journal, &rdev->flags)) {
8962                                         journal_dev_exists = true;
8963                                         break;
8964                                 }
8965
8966                         if (!journal_dev_exists) {
8967                                 mddev_suspend(mddev);
8968                                 clear_bit(MD_HAS_JOURNAL, &mddev->flags);
8969                                 mddev_resume(mddev);
8970                         } else  /* need remove journal device first */
8971                                 err = -EBUSY;
8972                 } else
8973                         err = -EINVAL;
8974         } else {
8975                 err = -EINVAL;
8976         }
8977
8978         if (!err)
8979                 md_update_sb(mddev, 1);
8980
8981         mddev_unlock(mddev);
8982
8983         return err;
8984 }
8985
8986 static int raid5_start(struct mddev *mddev)
8987 {
8988         struct r5conf *conf = mddev->private;
8989
8990         return r5l_start(conf->log);
8991 }
8992
8993 static struct md_personality raid6_personality =
8994 {
8995         .name           = "raid6",
8996         .level          = 6,
8997         .owner          = THIS_MODULE,
8998         .make_request   = raid5_make_request,
8999         .run            = raid5_run,
9000         .start          = raid5_start,
9001         .free           = raid5_free,
9002         .status         = raid5_status,
9003         .error_handler  = raid5_error,
9004         .hot_add_disk   = raid5_add_disk,
9005         .hot_remove_disk= raid5_remove_disk,
9006         .spare_active   = raid5_spare_active,
9007         .sync_request   = raid5_sync_request,
9008         .resize         = raid5_resize,
9009         .size           = raid5_size,
9010         .check_reshape  = raid6_check_reshape,
9011         .start_reshape  = raid5_start_reshape,
9012         .finish_reshape = raid5_finish_reshape,
9013         .quiesce        = raid5_quiesce,
9014         .takeover       = raid6_takeover,
9015         .change_consistency_policy = raid5_change_consistency_policy,
9016 };
9017 static struct md_personality raid5_personality =
9018 {
9019         .name           = "raid5",
9020         .level          = 5,
9021         .owner          = THIS_MODULE,
9022         .make_request   = raid5_make_request,
9023         .run            = raid5_run,
9024         .start          = raid5_start,
9025         .free           = raid5_free,
9026         .status         = raid5_status,
9027         .error_handler  = raid5_error,
9028         .hot_add_disk   = raid5_add_disk,
9029         .hot_remove_disk= raid5_remove_disk,
9030         .spare_active   = raid5_spare_active,
9031         .sync_request   = raid5_sync_request,
9032         .resize         = raid5_resize,
9033         .size           = raid5_size,
9034         .check_reshape  = raid5_check_reshape,
9035         .start_reshape  = raid5_start_reshape,
9036         .finish_reshape = raid5_finish_reshape,
9037         .quiesce        = raid5_quiesce,
9038         .takeover       = raid5_takeover,
9039         .change_consistency_policy = raid5_change_consistency_policy,
9040 };
9041
9042 static struct md_personality raid4_personality =
9043 {
9044         .name           = "raid4",
9045         .level          = 4,
9046         .owner          = THIS_MODULE,
9047         .make_request   = raid5_make_request,
9048         .run            = raid5_run,
9049         .start          = raid5_start,
9050         .free           = raid5_free,
9051         .status         = raid5_status,
9052         .error_handler  = raid5_error,
9053         .hot_add_disk   = raid5_add_disk,
9054         .hot_remove_disk= raid5_remove_disk,
9055         .spare_active   = raid5_spare_active,
9056         .sync_request   = raid5_sync_request,
9057         .resize         = raid5_resize,
9058         .size           = raid5_size,
9059         .check_reshape  = raid5_check_reshape,
9060         .start_reshape  = raid5_start_reshape,
9061         .finish_reshape = raid5_finish_reshape,
9062         .quiesce        = raid5_quiesce,
9063         .takeover       = raid4_takeover,
9064         .change_consistency_policy = raid5_change_consistency_policy,
9065 };
9066
9067 static int __init raid5_init(void)
9068 {
9069         int ret;
9070
9071         raid5_wq = alloc_workqueue("raid5wq",
9072                 WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE|WQ_SYSFS, 0);
9073         if (!raid5_wq)
9074                 return -ENOMEM;
9075
9076         ret = cpuhp_setup_state_multi(CPUHP_MD_RAID5_PREPARE,
9077                                       "md/raid5:prepare",
9078                                       raid456_cpu_up_prepare,
9079                                       raid456_cpu_dead);
9080         if (ret) {
9081                 destroy_workqueue(raid5_wq);
9082                 return ret;
9083         }
9084         register_md_personality(&raid6_personality);
9085         register_md_personality(&raid5_personality);
9086         register_md_personality(&raid4_personality);
9087         return 0;
9088 }
9089
9090 static void raid5_exit(void)
9091 {
9092         unregister_md_personality(&raid6_personality);
9093         unregister_md_personality(&raid5_personality);
9094         unregister_md_personality(&raid4_personality);
9095         cpuhp_remove_multi_state(CPUHP_MD_RAID5_PREPARE);
9096         destroy_workqueue(raid5_wq);
9097 }
9098
9099 module_init(raid5_init);
9100 module_exit(raid5_exit);
9101 MODULE_LICENSE("GPL");
9102 MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
9103 MODULE_ALIAS("md-personality-4"); /* RAID5 */
9104 MODULE_ALIAS("md-raid5");
9105 MODULE_ALIAS("md-raid4");
9106 MODULE_ALIAS("md-level-5");
9107 MODULE_ALIAS("md-level-4");
9108 MODULE_ALIAS("md-personality-8"); /* RAID6 */
9109 MODULE_ALIAS("md-raid6");
9110 MODULE_ALIAS("md-level-6");
9111
9112 /* This used to be two separate modules, they were: */
9113 MODULE_ALIAS("raid5");
9114 MODULE_ALIAS("raid6");