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/delay.h>
  40 #include <linux/kthread.h>
  41 #include <linux/raid/pq.h>
  42 #include <linux/async_tx.h>
  43 #include <linux/module.h>
  44 #include <linux/async.h>
  45 #include <linux/seq_file.h>
  46 #include <linux/cpu.h>
  47 #include <linux/slab.h>
  48 #include <linux/ratelimit.h>
  49 #include <linux/nodemask.h>
  50
  51 #include <trace/events/block.h>
  52 #include <linux/list_sort.h>
  53
  54 #include "md.h"
  55 #include "raid5.h"
  56 #include "raid0.h"
  57 #include "md-bitmap.h"
  58 #include "raid5-log.h"
  59
  60 #define UNSUPPORTED_MDDEV_FLAGS (1L << MD_FAILFAST_SUPPORTED)
  61
  62 #define cpu_to_group(cpu) cpu_to_node(cpu)
  63 #define ANY_GROUP NUMA_NO_NODE
  64
  65 #define RAID5_MAX_REQ_STRIPES 256
  66
  67 static bool devices_handle_discard_safely = false;
  68 module_param(devices_handle_discard_safely, bool, 0644);
  69 MODULE_PARM_DESC(devices_handle_discard_safely,
  70                  "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
  71 static struct workqueue_struct *raid5_wq;
  72
  73 static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
  74 {
  75         int hash = (sect >> RAID5_STRIPE_SHIFT(conf)) & HASH_MASK;
  76         return &conf->stripe_hashtbl[hash];
  77 }
  78
  79 static inline int stripe_hash_locks_hash(struct r5conf *conf, sector_t sect)
  80 {
  81         return (sect >> RAID5_STRIPE_SHIFT(conf)) & STRIPE_HASH_LOCKS_MASK;
  82 }
  83
  84 static inline void lock_device_hash_lock(struct r5conf *conf, int hash)
  85         __acquires(&conf->device_lock)
  86 {
  87         spin_lock_irq(conf->hash_locks + hash);
  88         spin_lock(&conf->device_lock);
  89 }
  90
  91 static inline void unlock_device_hash_lock(struct r5conf *conf, int hash)
  92         __releases(&conf->device_lock)
  93 {
  94         spin_unlock(&conf->device_lock);
  95         spin_unlock_irq(conf->hash_locks + hash);
  96 }
  97
  98 static inline void lock_all_device_hash_locks_irq(struct r5conf *conf)
  99         __acquires(&conf->device_lock)
 100 {
 101         int i;
 102         spin_lock_irq(conf->hash_locks);
 103         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
 104                 spin_lock_nest_lock(conf->hash_locks + i, conf->hash_locks);
 105         spin_lock(&conf->device_lock);
 106 }
 107
 108 static inline void unlock_all_device_hash_locks_irq(struct r5conf *conf)
 109         __releases(&conf->device_lock)
 110 {
 111         int i;
 112         spin_unlock(&conf->device_lock);
 113         for (i = NR_STRIPE_HASH_LOCKS - 1; i; i--)
 114                 spin_unlock(conf->hash_locks + i);
 115         spin_unlock_irq(conf->hash_locks);
 116 }
 117
 118 /* Find first data disk in a raid6 stripe */
 119 static inline int raid6_d0(struct stripe_head *sh)
 120 {
 121         if (sh->ddf_layout)
 122                 /* ddf always start from first device */
 123                 return 0;
 124         /* md starts just after Q block */
 125         if (sh->qd_idx == sh->disks - 1)
 126                 return 0;
 127         else
 128                 return sh->qd_idx + 1;
 129 }
 130 static inline int raid6_next_disk(int disk, int raid_disks)
 131 {
 132         disk++;
 133         return (disk < raid_disks) ? disk : 0;
 134 }
 135
 136 /* When walking through the disks in a raid5, starting at raid6_d0,
 137  * We need to map each disk to a 'slot', where the data disks are slot
 138  * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
 139  * is raid_disks-1.  This help does that mapping.
 140  */
 141 static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
 142                              int *count, int syndrome_disks)
 143 {
 144         int slot = *count;
 145
 146         if (sh->ddf_layout)
 147                 (*count)++;
 148         if (idx == sh->pd_idx)
 149                 return syndrome_disks;
 150         if (idx == sh->qd_idx)
 151                 return syndrome_disks + 1;
 152         if (!sh->ddf_layout)
 153                 (*count)++;
 154         return slot;
 155 }
 156
 157 static void print_raid5_conf (struct r5conf *conf);
 158
 159 static int stripe_operations_active(struct stripe_head *sh)
 160 {
 161         return sh->check_state || sh->reconstruct_state ||
 162                test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
 163                test_bit(STRIPE_COMPUTE_RUN, &sh->state);
 164 }
 165
 166 static bool stripe_is_lowprio(struct stripe_head *sh)
 167 {
 168         return (test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) ||
 169                 test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) &&
 170                !test_bit(STRIPE_R5C_CACHING, &sh->state);
 171 }
 172
 173 static void raid5_wakeup_stripe_thread(struct stripe_head *sh)
 174         __must_hold(&sh->raid_conf->device_lock)
 175 {
 176         struct r5conf *conf = sh->raid_conf;
 177         struct r5worker_group *group;
 178         int thread_cnt;
 179         int i, cpu = sh->cpu;
 180
 181         if (!cpu_online(cpu)) {
 182                 cpu = cpumask_any(cpu_online_mask);
 183                 sh->cpu = cpu;
 184         }
 185
 186         if (list_empty(&sh->lru)) {
 187                 struct r5worker_group *group;
 188                 group = conf->worker_groups + cpu_to_group(cpu);
 189                 if (stripe_is_lowprio(sh))
 190                         list_add_tail(&sh->lru, &group->loprio_list);
 191                 else
 192                         list_add_tail(&sh->lru, &group->handle_list);
 193                 group->stripes_cnt++;
 194                 sh->group = group;
 195         }
 196
 197         if (conf->worker_cnt_per_group == 0) {
 198                 md_wakeup_thread(conf->mddev->thread);
 199                 return;
 200         }
 201
 202         group = conf->worker_groups + cpu_to_group(sh->cpu);
 203
 204         group->workers[0].working = true;
 205         /* at least one worker should run to avoid race */
 206         queue_work_on(sh->cpu, raid5_wq, &group->workers[0].work);
 207
 208         thread_cnt = group->stripes_cnt / MAX_STRIPE_BATCH - 1;
 209         /* wakeup more workers */
 210         for (i = 1; i < conf->worker_cnt_per_group && thread_cnt > 0; i++) {
 211                 if (group->workers[i].working == false) {
 212                         group->workers[i].working = true;
 213                         queue_work_on(sh->cpu, raid5_wq,
 214                                       &group->workers[i].work);
 215                         thread_cnt--;
 216                 }
 217         }
 218 }
 219
 220 static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh,
 221                               struct list_head *temp_inactive_list)
 222         __must_hold(&conf->device_lock)
 223 {
 224         int i;
 225         int injournal = 0;      /* number of date pages with R5_InJournal */
 226
 227         BUG_ON(!list_empty(&sh->lru));
 228         BUG_ON(atomic_read(&conf->active_stripes)==0);
 229
 230         if (r5c_is_writeback(conf->log))
 231                 for (i = sh->disks; i--; )
 232                         if (test_bit(R5_InJournal, &sh->dev[i].flags))
 233                                 injournal++;
 234         /*
 235          * In the following cases, the stripe cannot be released to cached
 236          * lists. Therefore, we make the stripe write out and set
 237          * STRIPE_HANDLE:
 238          *   1. when quiesce in r5c write back;
 239          *   2. when resync is requested fot the stripe.
 240          */
 241         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) ||
 242             (conf->quiesce && r5c_is_writeback(conf->log) &&
 243              !test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0)) {
 244                 if (test_bit(STRIPE_R5C_CACHING, &sh->state))
 245                         r5c_make_stripe_write_out(sh);
 246                 set_bit(STRIPE_HANDLE, &sh->state);
 247         }
 248
 249         if (test_bit(STRIPE_HANDLE, &sh->state)) {
 250                 if (test_bit(STRIPE_DELAYED, &sh->state) &&
 251                     !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 252                         list_add_tail(&sh->lru, &conf->delayed_list);
 253                 else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
 254                            sh->bm_seq - conf->seq_write > 0)
 255                         list_add_tail(&sh->lru, &conf->bitmap_list);
 256                 else {
 257                         clear_bit(STRIPE_DELAYED, &sh->state);
 258                         clear_bit(STRIPE_BIT_DELAY, &sh->state);
 259                         if (conf->worker_cnt_per_group == 0) {
 260                                 if (stripe_is_lowprio(sh))
 261                                         list_add_tail(&sh->lru,
 262                                                         &conf->loprio_list);
 263                                 else
 264                                         list_add_tail(&sh->lru,
 265                                                         &conf->handle_list);
 266                         } else {
 267                                 raid5_wakeup_stripe_thread(sh);
 268                                 return;
 269                         }
 270                 }
 271                 md_wakeup_thread(conf->mddev->thread);
 272         } else {
 273                 BUG_ON(stripe_operations_active(sh));
 274                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 275                         if (atomic_dec_return(&conf->preread_active_stripes)
 276                             < IO_THRESHOLD)
 277                                 md_wakeup_thread(conf->mddev->thread);
 278                 atomic_dec(&conf->active_stripes);
 279                 if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
 280                         if (!r5c_is_writeback(conf->log))
 281                                 list_add_tail(&sh->lru, temp_inactive_list);
 282                         else {
 283                                 WARN_ON(test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags));
 284                                 if (injournal == 0)
 285                                         list_add_tail(&sh->lru, temp_inactive_list);
 286                                 else if (injournal == conf->raid_disks - conf->max_degraded) {
 287                                         /* full stripe */
 288                                         if (!test_and_set_bit(STRIPE_R5C_FULL_STRIPE, &sh->state))
 289                                                 atomic_inc(&conf->r5c_cached_full_stripes);
 290                                         if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
 291                                                 atomic_dec(&conf->r5c_cached_partial_stripes);
 292                                         list_add_tail(&sh->lru, &conf->r5c_full_stripe_list);
 293                                         r5c_check_cached_full_stripe(conf);
 294                                 } else
 295                                         /*
 296                                          * STRIPE_R5C_PARTIAL_STRIPE is set in
 297                                          * r5c_try_caching_write(). No need to
 298                                          * set it again.
 299                                          */
 300                                         list_add_tail(&sh->lru, &conf->r5c_partial_stripe_list);
 301                         }
 302                 }
 303         }
 304 }
 305
 306 static void __release_stripe(struct r5conf *conf, struct stripe_head *sh,
 307                              struct list_head *temp_inactive_list)
 308         __must_hold(&conf->device_lock)
 309 {
 310         if (atomic_dec_and_test(&sh->count))
 311                 do_release_stripe(conf, sh, temp_inactive_list);
 312 }
 313
 314 /*
 315  * @hash could be NR_STRIPE_HASH_LOCKS, then we have a list of inactive_list
 316  *
 317  * Be careful: Only one task can add/delete stripes from temp_inactive_list at
 318  * given time. Adding stripes only takes device lock, while deleting stripes
 319  * only takes hash lock.
 320  */
 321 static void release_inactive_stripe_list(struct r5conf *conf,
 322                                          struct list_head *temp_inactive_list,
 323                                          int hash)
 324 {
 325         int size;
 326         bool do_wakeup = false;
 327         unsigned long flags;
 328
 329         if (hash == NR_STRIPE_HASH_LOCKS) {
 330                 size = NR_STRIPE_HASH_LOCKS;
 331                 hash = NR_STRIPE_HASH_LOCKS - 1;
 332         } else
 333                 size = 1;
 334         while (size) {
 335                 struct list_head *list = &temp_inactive_list[size - 1];
 336
 337                 /*
 338                  * We don't hold any lock here yet, raid5_get_active_stripe() might
 339                  * remove stripes from the list
 340                  */
 341                 if (!list_empty_careful(list)) {
 342                         spin_lock_irqsave(conf->hash_locks + hash, flags);
 343                         if (list_empty(conf->inactive_list + hash) &&
 344                             !list_empty(list))
 345                                 atomic_dec(&conf->empty_inactive_list_nr);
 346                         list_splice_tail_init(list, conf->inactive_list + hash);
 347                         do_wakeup = true;
 348                         spin_unlock_irqrestore(conf->hash_locks + hash, flags);
 349                 }
 350                 size--;
 351                 hash--;
 352         }
 353
 354         if (do_wakeup) {
 355                 wake_up(&conf->wait_for_stripe);
 356                 if (atomic_read(&conf->active_stripes) == 0)
 357                         wake_up(&conf->wait_for_quiescent);
 358                 if (conf->retry_read_aligned)
 359                         md_wakeup_thread(conf->mddev->thread);
 360         }
 361 }
 362
 363 static int release_stripe_list(struct r5conf *conf,
 364                                struct list_head *temp_inactive_list)
 365         __must_hold(&conf->device_lock)
 366 {
 367         struct stripe_head *sh, *t;
 368         int count = 0;
 369         struct llist_node *head;
 370
 371         head = llist_del_all(&conf->released_stripes);
 372         head = llist_reverse_order(head);
 373         llist_for_each_entry_safe(sh, t, head, release_list) {
 374                 int hash;
 375
 376                 /* sh could be readded after STRIPE_ON_RELEASE_LIST is cleard */
 377                 smp_mb();
 378                 clear_bit(STRIPE_ON_RELEASE_LIST, &sh->state);
 379                 /*
 380                  * Don't worry the bit is set here, because if the bit is set
 381                  * again, the count is always > 1. This is true for
 382                  * STRIPE_ON_UNPLUG_LIST bit too.
 383                  */
 384                 hash = sh->hash_lock_index;
 385                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
 386                 count++;
 387         }
 388
 389         return count;
 390 }
 391
 392 void raid5_release_stripe(struct stripe_head *sh)
 393 {
 394         struct r5conf *conf = sh->raid_conf;
 395         unsigned long flags;
 396         struct list_head list;
 397         int hash;
 398         bool wakeup;
 399
 400         /* Avoid release_list until the last reference.
 401          */
 402         if (atomic_add_unless(&sh->count, -1, 1))
 403                 return;
 404
 405         if (unlikely(!conf->mddev->thread) ||
 406                 test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state))
 407                 goto slow_path;
 408         wakeup = llist_add(&sh->release_list, &conf->released_stripes);
 409         if (wakeup)
 410                 md_wakeup_thread(conf->mddev->thread);
 411         return;
 412 slow_path:
 413         /* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */
 414         if (atomic_dec_and_lock_irqsave(&sh->count, &conf->device_lock, flags)) {
 415                 INIT_LIST_HEAD(&list);
 416                 hash = sh->hash_lock_index;
 417                 do_release_stripe(conf, sh, &list);
 418                 spin_unlock_irqrestore(&conf->device_lock, flags);
 419                 release_inactive_stripe_list(conf, &list, hash);
 420         }
 421 }
 422
 423 static inline void remove_hash(struct stripe_head *sh)
 424 {
 425         pr_debug("remove_hash(), stripe %llu\n",
 426                 (unsigned long long)sh->sector);
 427
 428         hlist_del_init(&sh->hash);
 429 }
 430
 431 static inline void insert_hash(struct r5conf *conf, struct stripe_head *sh)
 432 {
 433         struct hlist_head *hp = stripe_hash(conf, sh->sector);
 434
 435         pr_debug("insert_hash(), stripe %llu\n",
 436                 (unsigned long long)sh->sector);
 437
 438         hlist_add_head(&sh->hash, hp);
 439 }
 440
 441 /* find an idle stripe, make sure it is unhashed, and return it. */
 442 static struct stripe_head *get_free_stripe(struct r5conf *conf, int hash)
 443 {
 444         struct stripe_head *sh = NULL;
 445         struct list_head *first;
 446
 447         if (list_empty(conf->inactive_list + hash))
 448                 goto out;
 449         first = (conf->inactive_list + hash)->next;
 450         sh = list_entry(first, struct stripe_head, lru);
 451         list_del_init(first);
 452         remove_hash(sh);
 453         atomic_inc(&conf->active_stripes);
 454         BUG_ON(hash != sh->hash_lock_index);
 455         if (list_empty(conf->inactive_list + hash))
 456                 atomic_inc(&conf->empty_inactive_list_nr);
 457 out:
 458         return sh;
 459 }
 460
 461 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
 462 static void free_stripe_pages(struct stripe_head *sh)
 463 {
 464         int i;
 465         struct page *p;
 466
 467         /* Have not allocate page pool */
 468         if (!sh->pages)
 469                 return;
 470
 471         for (i = 0; i < sh->nr_pages; i++) {
 472                 p = sh->pages[i];
 473                 if (p)
 474                         put_page(p);
 475                 sh->pages[i] = NULL;
 476         }
 477 }
 478
 479 static int alloc_stripe_pages(struct stripe_head *sh, gfp_t gfp)
 480 {
 481         int i;
 482         struct page *p;
 483
 484         for (i = 0; i < sh->nr_pages; i++) {
 485                 /* The page have allocated. */
 486                 if (sh->pages[i])
 487                         continue;
 488
 489                 p = alloc_page(gfp);
 490                 if (!p) {
 491                         free_stripe_pages(sh);
 492                         return -ENOMEM;
 493                 }
 494                 sh->pages[i] = p;
 495         }
 496         return 0;
 497 }
 498
 499 static int
 500 init_stripe_shared_pages(struct stripe_head *sh, struct r5conf *conf, int disks)
 501 {
 502         int nr_pages, cnt;
 503
 504         if (sh->pages)
 505                 return 0;
 506
 507         /* Each of the sh->dev[i] need one conf->stripe_size */
 508         cnt = PAGE_SIZE / conf->stripe_size;
 509         nr_pages = (disks + cnt - 1) / cnt;
 510
 511         sh->pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
 512         if (!sh->pages)
 513                 return -ENOMEM;
 514         sh->nr_pages = nr_pages;
 515         sh->stripes_per_page = cnt;
 516         return 0;
 517 }
 518 #endif
 519
 520 static void shrink_buffers(struct stripe_head *sh)
 521 {
 522         int i;
 523         int num = sh->raid_conf->pool_size;
 524
 525 #if PAGE_SIZE == DEFAULT_STRIPE_SIZE
 526         for (i = 0; i < num ; i++) {
 527                 struct page *p;
 528
 529                 WARN_ON(sh->dev[i].page != sh->dev[i].orig_page);
 530                 p = sh->dev[i].page;
 531                 if (!p)
 532                         continue;
 533                 sh->dev[i].page = NULL;
 534                 put_page(p);
 535         }
 536 #else
 537         for (i = 0; i < num; i++)
 538                 sh->dev[i].page = NULL;
 539         free_stripe_pages(sh); /* Free pages */
 540 #endif
 541 }
 542
 543 static int grow_buffers(struct stripe_head *sh, gfp_t gfp)
 544 {
 545         int i;
 546         int num = sh->raid_conf->pool_size;
 547
 548 #if PAGE_SIZE == DEFAULT_STRIPE_SIZE
 549         for (i = 0; i < num; i++) {
 550                 struct page *page;
 551
 552                 if (!(page = alloc_page(gfp))) {
 553                         return 1;
 554                 }
 555                 sh->dev[i].page = page;
 556                 sh->dev[i].orig_page = page;
 557                 sh->dev[i].offset = 0;
 558         }
 559 #else
 560         if (alloc_stripe_pages(sh, gfp))
 561                 return -ENOMEM;
 562
 563         for (i = 0; i < num; i++) {
 564                 sh->dev[i].page = raid5_get_dev_page(sh, i);
 565                 sh->dev[i].orig_page = sh->dev[i].page;
 566                 sh->dev[i].offset = raid5_get_page_offset(sh, i);
 567         }
 568 #endif
 569         return 0;
 570 }
 571
 572 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
 573                             struct stripe_head *sh);
 574
 575 static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
 576 {
 577         struct r5conf *conf = sh->raid_conf;
 578         int i, seq;
 579
 580         BUG_ON(atomic_read(&sh->count) != 0);
 581         BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
 582         BUG_ON(stripe_operations_active(sh));
 583         BUG_ON(sh->batch_head);
 584
 585         pr_debug("init_stripe called, stripe %llu\n",
 586                 (unsigned long long)sector);
 587 retry:
 588         seq = read_seqcount_begin(&conf->gen_lock);
 589         sh->generation = conf->generation - previous;
 590         sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
 591         sh->sector = sector;
 592         stripe_set_idx(sector, conf, previous, sh);
 593         sh->state = 0;
 594
 595         for (i = sh->disks; i--; ) {
 596                 struct r5dev *dev = &sh->dev[i];
 597
 598                 if (dev->toread || dev->read || dev->towrite || dev->written ||
 599                     test_bit(R5_LOCKED, &dev->flags)) {
 600                         pr_err("sector=%llx i=%d %p %p %p %p %d\n",
 601                                (unsigned long long)sh->sector, i, dev->toread,
 602                                dev->read, dev->towrite, dev->written,
 603                                test_bit(R5_LOCKED, &dev->flags));
 604                         WARN_ON(1);
 605                 }
 606                 dev->flags = 0;
 607                 dev->sector = raid5_compute_blocknr(sh, i, previous);
 608         }
 609         if (read_seqcount_retry(&conf->gen_lock, seq))
 610                 goto retry;
 611         sh->overwrite_disks = 0;
 612         insert_hash(conf, sh);
 613         sh->cpu = smp_processor_id();
 614         set_bit(STRIPE_BATCH_READY, &sh->state);
 615 }
 616
 617 static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
 618                                          short generation)
 619 {
 620         struct stripe_head *sh;
 621
 622         pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
 623         hlist_for_each_entry(sh, stripe_hash(conf, sector), hash)
 624                 if (sh->sector == sector && sh->generation == generation)
 625                         return sh;
 626         pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
 627         return NULL;
 628 }
 629
 630 static struct stripe_head *find_get_stripe(struct r5conf *conf,
 631                 sector_t sector, short generation, int hash)
 632 {
 633         int inc_empty_inactive_list_flag;
 634         struct stripe_head *sh;
 635
 636         sh = __find_stripe(conf, sector, generation);
 637         if (!sh)
 638                 return NULL;
 639
 640         if (atomic_inc_not_zero(&sh->count))
 641                 return sh;
 642
 643         /*
 644          * Slow path. The reference count is zero which means the stripe must
 645          * be on a list (sh->lru). Must remove the stripe from the list that
 646          * references it with the device_lock held.
 647          */
 648
 649         spin_lock(&conf->device_lock);
 650         if (!atomic_read(&sh->count)) {
 651                 if (!test_bit(STRIPE_HANDLE, &sh->state))
 652                         atomic_inc(&conf->active_stripes);
 653                 BUG_ON(list_empty(&sh->lru) &&
 654                        !test_bit(STRIPE_EXPANDING, &sh->state));
 655                 inc_empty_inactive_list_flag = 0;
 656                 if (!list_empty(conf->inactive_list + hash))
 657                         inc_empty_inactive_list_flag = 1;
 658                 list_del_init(&sh->lru);
 659                 if (list_empty(conf->inactive_list + hash) &&
 660                     inc_empty_inactive_list_flag)
 661                         atomic_inc(&conf->empty_inactive_list_nr);
 662                 if (sh->group) {
 663                         sh->group->stripes_cnt--;
 664                         sh->group = NULL;
 665                 }
 666         }
 667         atomic_inc(&sh->count);
 668         spin_unlock(&conf->device_lock);
 669
 670         return sh;
 671 }
 672
 673 /*
 674  * Need to check if array has failed when deciding whether to:
 675  *  - start an array
 676  *  - remove non-faulty devices
 677  *  - add a spare
 678  *  - allow a reshape
 679  * This determination is simple when no reshape is happening.
 680  * However if there is a reshape, we need to carefully check
 681  * both the before and after sections.
 682  * This is because some failed devices may only affect one
 683  * of the two sections, and some non-in_sync devices may
 684  * be insync in the section most affected by failed devices.
 685  *
 686  * Most calls to this function hold &conf->device_lock. Calls
 687  * in raid5_run() do not require the lock as no other threads
 688  * have been started yet.
 689  */
 690 int raid5_calc_degraded(struct r5conf *conf)
 691 {
 692         int degraded, degraded2;
 693         int i;
 694
 695         rcu_read_lock();
 696         degraded = 0;
 697         for (i = 0; i < conf->previous_raid_disks; i++) {
 698                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 699                 if (rdev && test_bit(Faulty, &rdev->flags))
 700                         rdev = rcu_dereference(conf->disks[i].replacement);
 701                 if (!rdev || test_bit(Faulty, &rdev->flags))
 702                         degraded++;
 703                 else if (test_bit(In_sync, &rdev->flags))
 704                         ;
 705                 else
 706                         /* not in-sync or faulty.
 707                          * If the reshape increases the number of devices,
 708                          * this is being recovered by the reshape, so
 709                          * this 'previous' section is not in_sync.
 710                          * If the number of devices is being reduced however,
 711                          * the device can only be part of the array if
 712                          * we are reverting a reshape, so this section will
 713                          * be in-sync.
 714                          */
 715                         if (conf->raid_disks >= conf->previous_raid_disks)
 716                                 degraded++;
 717         }
 718         rcu_read_unlock();
 719         if (conf->raid_disks == conf->previous_raid_disks)
 720                 return degraded;
 721         rcu_read_lock();
 722         degraded2 = 0;
 723         for (i = 0; i < conf->raid_disks; i++) {
 724                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 725                 if (rdev && test_bit(Faulty, &rdev->flags))
 726                         rdev = rcu_dereference(conf->disks[i].replacement);
 727                 if (!rdev || test_bit(Faulty, &rdev->flags))
 728                         degraded2++;
 729                 else if (test_bit(In_sync, &rdev->flags))
 730                         ;
 731                 else
 732                         /* not in-sync or faulty.
 733                          * If reshape increases the number of devices, this
 734                          * section has already been recovered, else it
 735                          * almost certainly hasn't.
 736                          */
 737                         if (conf->raid_disks <= conf->previous_raid_disks)
 738                                 degraded2++;
 739         }
 740         rcu_read_unlock();
 741         if (degraded2 > degraded)
 742                 return degraded2;
 743         return degraded;
 744 }
 745
 746 static bool has_failed(struct r5conf *conf)
 747 {
 748         int degraded = conf->mddev->degraded;
 749
 750         if (test_bit(MD_BROKEN, &conf->mddev->flags))
 751                 return true;
 752
 753         if (conf->mddev->reshape_position != MaxSector)
 754                 degraded = raid5_calc_degraded(conf);
 755
 756         return degraded > conf->max_degraded;
 757 }
 758
 759 enum stripe_result {
 760         STRIPE_SUCCESS = 0,
 761         STRIPE_RETRY,
 762         STRIPE_SCHEDULE_AND_RETRY,
 763         STRIPE_FAIL,
 764 };
 765
 766 struct stripe_request_ctx {
 767         /* a reference to the last stripe_head for batching */
 768         struct stripe_head *batch_last;
 769
 770         /* first sector in the request */
 771         sector_t first_sector;
 772
 773         /* last sector in the request */
 774         sector_t last_sector;
 775
 776         /*
 777          * bitmap to track stripe sectors that have been added to stripes
 778          * add one to account for unaligned requests
 779          */
 780         DECLARE_BITMAP(sectors_to_do, RAID5_MAX_REQ_STRIPES + 1);
 781
 782         /* the request had REQ_PREFLUSH, cleared after the first stripe_head */
 783         bool do_flush;
 784 };
 785
 786 /*
 787  * Block until another thread clears R5_INACTIVE_BLOCKED or
 788  * there are fewer than 3/4 the maximum number of active stripes
 789  * and there is an inactive stripe available.
 790  */
 791 static bool is_inactive_blocked(struct r5conf *conf, int hash)
 792 {
 793         if (list_empty(conf->inactive_list + hash))
 794                 return false;
 795
 796         if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
 797                 return true;
 798
 799         return (atomic_read(&conf->active_stripes) <
 800                 (conf->max_nr_stripes * 3 / 4));
 801 }
 802
 803 struct stripe_head *raid5_get_active_stripe(struct r5conf *conf,
 804                 struct stripe_request_ctx *ctx, sector_t sector,
 805                 unsigned int flags)
 806 {
 807         struct stripe_head *sh;
 808         int hash = stripe_hash_locks_hash(conf, sector);
 809         int previous = !!(flags & R5_GAS_PREVIOUS);
 810
 811         pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
 812
 813         spin_lock_irq(conf->hash_locks + hash);
 814
 815         for (;;) {
 816                 if (!(flags & R5_GAS_NOQUIESCE) && conf->quiesce) {
 817                         /*
 818                          * Must release the reference to batch_last before
 819                          * waiting, on quiesce, otherwise the batch_last will
 820                          * hold a reference to a stripe and raid5_quiesce()
 821                          * will deadlock waiting for active_stripes to go to
 822                          * zero.
 823                          */
 824                         if (ctx && ctx->batch_last) {
 825                                 raid5_release_stripe(ctx->batch_last);
 826                                 ctx->batch_last = NULL;
 827                         }
 828
 829                         wait_event_lock_irq(conf->wait_for_quiescent,
 830                                             !conf->quiesce,
 831                                             *(conf->hash_locks + hash));
 832                 }
 833
 834                 sh = find_get_stripe(conf, sector, conf->generation - previous,
 835                                      hash);
 836                 if (sh)
 837                         break;
 838
 839                 if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state)) {
 840                         sh = get_free_stripe(conf, hash);
 841                         if (sh) {
 842                                 r5c_check_stripe_cache_usage(conf);
 843                                 init_stripe(sh, sector, previous);
 844                                 atomic_inc(&sh->count);
 845                                 break;
 846                         }
 847
 848                         if (!test_bit(R5_DID_ALLOC, &conf->cache_state))
 849                                 set_bit(R5_ALLOC_MORE, &conf->cache_state);
 850                 }
 851
 852                 if (flags & R5_GAS_NOBLOCK)
 853                         break;
 854
 855                 set_bit(R5_INACTIVE_BLOCKED, &conf->cache_state);
 856                 r5l_wake_reclaim(conf->log, 0);
 857
 858                 /* release batch_last before wait to avoid risk of deadlock */
 859                 if (ctx && ctx->batch_last) {
 860                         raid5_release_stripe(ctx->batch_last);
 861                         ctx->batch_last = NULL;
 862                 }
 863
 864                 wait_event_lock_irq(conf->wait_for_stripe,
 865                                     is_inactive_blocked(conf, hash),
 866                                     *(conf->hash_locks + hash));
 867                 clear_bit(R5_INACTIVE_BLOCKED, &conf->cache_state);
 868         }
 869
 870         spin_unlock_irq(conf->hash_locks + hash);
 871         return sh;
 872 }
 873
 874 static bool is_full_stripe_write(struct stripe_head *sh)
 875 {
 876         BUG_ON(sh->overwrite_disks > (sh->disks - sh->raid_conf->max_degraded));
 877         return sh->overwrite_disks == (sh->disks - sh->raid_conf->max_degraded);
 878 }
 879
 880 static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 881                 __acquires(&sh1->stripe_lock)
 882                 __acquires(&sh2->stripe_lock)
 883 {
 884         if (sh1 > sh2) {
 885                 spin_lock_irq(&sh2->stripe_lock);
 886                 spin_lock_nested(&sh1->stripe_lock, 1);
 887         } else {
 888                 spin_lock_irq(&sh1->stripe_lock);
 889                 spin_lock_nested(&sh2->stripe_lock, 1);
 890         }
 891 }
 892
 893 static void unlock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 894                 __releases(&sh1->stripe_lock)
 895                 __releases(&sh2->stripe_lock)
 896 {
 897         spin_unlock(&sh1->stripe_lock);
 898         spin_unlock_irq(&sh2->stripe_lock);
 899 }
 900
 901 /* Only freshly new full stripe normal write stripe can be added to a batch list */
 902 static bool stripe_can_batch(struct stripe_head *sh)
 903 {
 904         struct r5conf *conf = sh->raid_conf;
 905
 906         if (raid5_has_log(conf) || raid5_has_ppl(conf))
 907                 return false;
 908         return test_bit(STRIPE_BATCH_READY, &sh->state) &&
 909                 !test_bit(STRIPE_BITMAP_PENDING, &sh->state) &&
 910                 is_full_stripe_write(sh);
 911 }
 912
 913 /* we only do back search */
 914 static void stripe_add_to_batch_list(struct r5conf *conf,
 915                 struct stripe_head *sh, struct stripe_head *last_sh)
 916 {
 917         struct stripe_head *head;
 918         sector_t head_sector, tmp_sec;
 919         int hash;
 920         int dd_idx;
 921
 922         /* Don't cross chunks, so stripe pd_idx/qd_idx is the same */
 923         tmp_sec = sh->sector;
 924         if (!sector_div(tmp_sec, conf->chunk_sectors))
 925                 return;
 926         head_sector = sh->sector - RAID5_STRIPE_SECTORS(conf);
 927
 928         if (last_sh && head_sector == last_sh->sector) {
 929                 head = last_sh;
 930                 atomic_inc(&head->count);
 931         } else {
 932                 hash = stripe_hash_locks_hash(conf, head_sector);
 933                 spin_lock_irq(conf->hash_locks + hash);
 934                 head = find_get_stripe(conf, head_sector, conf->generation,
 935                                        hash);
 936                 spin_unlock_irq(conf->hash_locks + hash);
 937                 if (!head)
 938                         return;
 939                 if (!stripe_can_batch(head))
 940                         goto out;
 941         }
 942
 943         lock_two_stripes(head, sh);
 944         /* clear_batch_ready clear the flag */
 945         if (!stripe_can_batch(head) || !stripe_can_batch(sh))
 946                 goto unlock_out;
 947
 948         if (sh->batch_head)
 949                 goto unlock_out;
 950
 951         dd_idx = 0;
 952         while (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
 953                 dd_idx++;
 954         if (head->dev[dd_idx].towrite->bi_opf != sh->dev[dd_idx].towrite->bi_opf ||
 955             bio_op(head->dev[dd_idx].towrite) != bio_op(sh->dev[dd_idx].towrite))
 956                 goto unlock_out;
 957
 958         if (head->batch_head) {
 959                 spin_lock(&head->batch_head->batch_lock);
 960                 /* This batch list is already running */
 961                 if (!stripe_can_batch(head)) {
 962                         spin_unlock(&head->batch_head->batch_lock);
 963                         goto unlock_out;
 964                 }
 965                 /*
 966                  * We must assign batch_head of this stripe within the
 967                  * batch_lock, otherwise clear_batch_ready of batch head
 968                  * stripe could clear BATCH_READY bit of this stripe and
 969                  * this stripe->batch_head doesn't get assigned, which
 970                  * could confuse clear_batch_ready for this stripe
 971                  */
 972                 sh->batch_head = head->batch_head;
 973
 974                 /*
 975                  * at this point, head's BATCH_READY could be cleared, but we
 976                  * can still add the stripe to batch list
 977                  */
 978                 list_add(&sh->batch_list, &head->batch_list);
 979                 spin_unlock(&head->batch_head->batch_lock);
 980         } else {
 981                 head->batch_head = head;
 982                 sh->batch_head = head->batch_head;
 983                 spin_lock(&head->batch_lock);
 984                 list_add_tail(&sh->batch_list, &head->batch_list);
 985                 spin_unlock(&head->batch_lock);
 986         }
 987
 988         if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 989                 if (atomic_dec_return(&conf->preread_active_stripes)
 990                     < IO_THRESHOLD)
 991                         md_wakeup_thread(conf->mddev->thread);
 992
 993         if (test_and_clear_bit(STRIPE_BIT_DELAY, &sh->state)) {
 994                 int seq = sh->bm_seq;
 995                 if (test_bit(STRIPE_BIT_DELAY, &sh->batch_head->state) &&
 996                     sh->batch_head->bm_seq > seq)
 997                         seq = sh->batch_head->bm_seq;
 998                 set_bit(STRIPE_BIT_DELAY, &sh->batch_head->state);
 999                 sh->batch_head->bm_seq = seq;
1000         }
1001
1002         atomic_inc(&sh->count);
1003 unlock_out:
1004         unlock_two_stripes(head, sh);
1005 out:
1006         raid5_release_stripe(head);
1007 }
1008
1009 /* Determine if 'data_offset' or 'new_data_offset' should be used
1010  * in this stripe_head.
1011  */
1012 static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
1013 {
1014         sector_t progress = conf->reshape_progress;
1015         /* Need a memory barrier to make sure we see the value
1016          * of conf->generation, or ->data_offset that was set before
1017          * reshape_progress was updated.
1018          */
1019         smp_rmb();
1020         if (progress == MaxSector)
1021                 return 0;
1022         if (sh->generation == conf->generation - 1)
1023                 return 0;
1024         /* We are in a reshape, and this is a new-generation stripe,
1025          * so use new_data_offset.
1026          */
1027         return 1;
1028 }
1029
1030 static void dispatch_bio_list(struct bio_list *tmp)
1031 {
1032         struct bio *bio;
1033
1034         while ((bio = bio_list_pop(tmp)))
1035                 submit_bio_noacct(bio);
1036 }
1037
1038 static int cmp_stripe(void *priv, const struct list_head *a,
1039                       const struct list_head *b)
1040 {
1041         const struct r5pending_data *da = list_entry(a,
1042                                 struct r5pending_data, sibling);
1043         const struct r5pending_data *db = list_entry(b,
1044                                 struct r5pending_data, sibling);
1045         if (da->sector > db->sector)
1046                 return 1;
1047         if (da->sector < db->sector)
1048                 return -1;
1049         return 0;
1050 }
1051
1052 static void dispatch_defer_bios(struct r5conf *conf, int target,
1053                                 struct bio_list *list)
1054 {
1055         struct r5pending_data *data;
1056         struct list_head *first, *next = NULL;
1057         int cnt = 0;
1058
1059         if (conf->pending_data_cnt == 0)
1060                 return;
1061
1062         list_sort(NULL, &conf->pending_list, cmp_stripe);
1063
1064         first = conf->pending_list.next;
1065
1066         /* temporarily move the head */
1067         if (conf->next_pending_data)
1068                 list_move_tail(&conf->pending_list,
1069                                 &conf->next_pending_data->sibling);
1070
1071         while (!list_empty(&conf->pending_list)) {
1072                 data = list_first_entry(&conf->pending_list,
1073                         struct r5pending_data, sibling);
1074                 if (&data->sibling == first)
1075                         first = data->sibling.next;
1076                 next = data->sibling.next;
1077
1078                 bio_list_merge(list, &data->bios);
1079                 list_move(&data->sibling, &conf->free_list);
1080                 cnt++;
1081                 if (cnt >= target)
1082                         break;
1083         }
1084         conf->pending_data_cnt -= cnt;
1085         BUG_ON(conf->pending_data_cnt < 0 || cnt < target);
1086
1087         if (next != &conf->pending_list)
1088                 conf->next_pending_data = list_entry(next,
1089                                 struct r5pending_data, sibling);
1090         else
1091                 conf->next_pending_data = NULL;
1092         /* list isn't empty */
1093         if (first != &conf->pending_list)
1094                 list_move_tail(&conf->pending_list, first);
1095 }
1096
1097 static void flush_deferred_bios(struct r5conf *conf)
1098 {
1099         struct bio_list tmp = BIO_EMPTY_LIST;
1100
1101         if (conf->pending_data_cnt == 0)
1102                 return;
1103
1104         spin_lock(&conf->pending_bios_lock);
1105         dispatch_defer_bios(conf, conf->pending_data_cnt, &tmp);
1106         BUG_ON(conf->pending_data_cnt != 0);
1107         spin_unlock(&conf->pending_bios_lock);
1108
1109         dispatch_bio_list(&tmp);
1110 }
1111
1112 static void defer_issue_bios(struct r5conf *conf, sector_t sector,
1113                                 struct bio_list *bios)
1114 {
1115         struct bio_list tmp = BIO_EMPTY_LIST;
1116         struct r5pending_data *ent;
1117
1118         spin_lock(&conf->pending_bios_lock);
1119         ent = list_first_entry(&conf->free_list, struct r5pending_data,
1120                                                         sibling);
1121         list_move_tail(&ent->sibling, &conf->pending_list);
1122         ent->sector = sector;
1123         bio_list_init(&ent->bios);
1124         bio_list_merge(&ent->bios, bios);
1125         conf->pending_data_cnt++;
1126         if (conf->pending_data_cnt >= PENDING_IO_MAX)
1127                 dispatch_defer_bios(conf, PENDING_IO_ONE_FLUSH, &tmp);
1128
1129         spin_unlock(&conf->pending_bios_lock);
1130
1131         dispatch_bio_list(&tmp);
1132 }
1133
1134 static void
1135 raid5_end_read_request(struct bio *bi);
1136 static void
1137 raid5_end_write_request(struct bio *bi);
1138
1139 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
1140 {
1141         struct r5conf *conf = sh->raid_conf;
1142         int i, disks = sh->disks;
1143         struct stripe_head *head_sh = sh;
1144         struct bio_list pending_bios = BIO_EMPTY_LIST;
1145         struct r5dev *dev;
1146         bool should_defer;
1147
1148         might_sleep();
1149
1150         if (log_stripe(sh, s) == 0)
1151                 return;
1152
1153         should_defer = conf->batch_bio_dispatch && conf->group_cnt;
1154
1155         for (i = disks; i--; ) {
1156                 enum req_op op;
1157                 blk_opf_t op_flags = 0;
1158                 int replace_only = 0;
1159                 struct bio *bi, *rbi;
1160                 struct md_rdev *rdev, *rrdev = NULL;
1161
1162                 sh = head_sh;
1163                 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
1164                         op = REQ_OP_WRITE;
1165                         if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
1166                                 op_flags = REQ_FUA;
1167                         if (test_bit(R5_Discard, &sh->dev[i].flags))
1168                                 op = REQ_OP_DISCARD;
1169                 } else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1170                         op = REQ_OP_READ;
1171                 else if (test_and_clear_bit(R5_WantReplace,
1172                                             &sh->dev[i].flags)) {
1173                         op = REQ_OP_WRITE;
1174                         replace_only = 1;
1175                 } else
1176                         continue;
1177                 if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
1178                         op_flags |= REQ_SYNC;
1179
1180 again:
1181                 dev = &sh->dev[i];
1182                 bi = &dev->req;
1183                 rbi = &dev->rreq; /* For writing to replacement */
1184
1185                 rcu_read_lock();
1186                 rrdev = rcu_dereference(conf->disks[i].replacement);
1187                 smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
1188                 rdev = rcu_dereference(conf->disks[i].rdev);
1189                 if (!rdev) {
1190                         rdev = rrdev;
1191                         rrdev = NULL;
1192                 }
1193                 if (op_is_write(op)) {
1194                         if (replace_only)
1195                                 rdev = NULL;
1196                         if (rdev == rrdev)
1197                                 /* We raced and saw duplicates */
1198                                 rrdev = NULL;
1199                 } else {
1200                         if (test_bit(R5_ReadRepl, &head_sh->dev[i].flags) && rrdev)
1201                                 rdev = rrdev;
1202                         rrdev = NULL;
1203                 }
1204
1205                 if (rdev && test_bit(Faulty, &rdev->flags))
1206                         rdev = NULL;
1207                 if (rdev)
1208                         atomic_inc(&rdev->nr_pending);
1209                 if (rrdev && test_bit(Faulty, &rrdev->flags))
1210                         rrdev = NULL;
1211                 if (rrdev)
1212                         atomic_inc(&rrdev->nr_pending);
1213                 rcu_read_unlock();
1214
1215                 /* We have already checked bad blocks for reads.  Now
1216                  * need to check for writes.  We never accept write errors
1217                  * on the replacement, so we don't to check rrdev.
1218                  */
1219                 while (op_is_write(op) && rdev &&
1220                        test_bit(WriteErrorSeen, &rdev->flags)) {
1221                         sector_t first_bad;
1222                         int bad_sectors;
1223                         int bad = is_badblock(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf),
1224                                               &first_bad, &bad_sectors);
1225                         if (!bad)
1226                                 break;
1227
1228                         if (bad < 0) {
1229                                 set_bit(BlockedBadBlocks, &rdev->flags);
1230                                 if (!conf->mddev->external &&
1231                                     conf->mddev->sb_flags) {
1232                                         /* It is very unlikely, but we might
1233                                          * still need to write out the
1234                                          * bad block log - better give it
1235                                          * a chance*/
1236                                         md_check_recovery(conf->mddev);
1237                                 }
1238                                 /*
1239                                  * Because md_wait_for_blocked_rdev
1240                                  * will dec nr_pending, we must
1241                                  * increment it first.
1242                                  */
1243                                 atomic_inc(&rdev->nr_pending);
1244                                 md_wait_for_blocked_rdev(rdev, conf->mddev);
1245                         } else {
1246                                 /* Acknowledged bad block - skip the write */
1247                                 rdev_dec_pending(rdev, conf->mddev);
1248                                 rdev = NULL;
1249                         }
1250                 }
1251
1252                 if (rdev) {
1253                         if (s->syncing || s->expanding || s->expanded
1254                             || s->replacing)
1255                                 md_sync_acct(rdev->bdev, RAID5_STRIPE_SECTORS(conf));
1256
1257                         set_bit(STRIPE_IO_STARTED, &sh->state);
1258
1259                         bio_init(bi, rdev->bdev, &dev->vec, 1, op | op_flags);
1260                         bi->bi_end_io = op_is_write(op)
1261                                 ? raid5_end_write_request
1262                                 : raid5_end_read_request;
1263                         bi->bi_private = sh;
1264
1265                         pr_debug("%s: for %llu schedule op %d on disc %d\n",
1266                                 __func__, (unsigned long long)sh->sector,
1267                                 bi->bi_opf, i);
1268                         atomic_inc(&sh->count);
1269                         if (sh != head_sh)
1270                                 atomic_inc(&head_sh->count);
1271                         if (use_new_offset(conf, sh))
1272                                 bi->bi_iter.bi_sector = (sh->sector
1273                                                  + rdev->new_data_offset);
1274                         else
1275                                 bi->bi_iter.bi_sector = (sh->sector
1276                                                  + rdev->data_offset);
1277                         if (test_bit(R5_ReadNoMerge, &head_sh->dev[i].flags))
1278                                 bi->bi_opf |= REQ_NOMERGE;
1279
1280                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1281                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1282
1283                         if (!op_is_write(op) &&
1284                             test_bit(R5_InJournal, &sh->dev[i].flags))
1285                                 /*
1286                                  * issuing read for a page in journal, this
1287                                  * must be preparing for prexor in rmw; read
1288                                  * the data into orig_page
1289                                  */
1290                                 sh->dev[i].vec.bv_page = sh->dev[i].orig_page;
1291                         else
1292                                 sh->dev[i].vec.bv_page = sh->dev[i].page;
1293                         bi->bi_vcnt = 1;
1294                         bi->bi_io_vec[0].bv_len = RAID5_STRIPE_SIZE(conf);
1295                         bi->bi_io_vec[0].bv_offset = sh->dev[i].offset;
1296                         bi->bi_iter.bi_size = RAID5_STRIPE_SIZE(conf);
1297                         /*
1298                          * If this is discard request, set bi_vcnt 0. We don't
1299                          * want to confuse SCSI because SCSI will replace payload
1300                          */
1301                         if (op == REQ_OP_DISCARD)
1302                                 bi->bi_vcnt = 0;
1303                         if (rrdev)
1304                                 set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
1305
1306                         if (conf->mddev->gendisk)
1307                                 trace_block_bio_remap(bi,
1308                                                 disk_devt(conf->mddev->gendisk),
1309                                                 sh->dev[i].sector);
1310                         if (should_defer && op_is_write(op))
1311                                 bio_list_add(&pending_bios, bi);
1312                         else
1313                                 submit_bio_noacct(bi);
1314                 }
1315                 if (rrdev) {
1316                         if (s->syncing || s->expanding || s->expanded
1317                             || s->replacing)
1318                                 md_sync_acct(rrdev->bdev, RAID5_STRIPE_SECTORS(conf));
1319
1320                         set_bit(STRIPE_IO_STARTED, &sh->state);
1321
1322                         bio_init(rbi, rrdev->bdev, &dev->rvec, 1, op | op_flags);
1323                         BUG_ON(!op_is_write(op));
1324                         rbi->bi_end_io = raid5_end_write_request;
1325                         rbi->bi_private = sh;
1326
1327                         pr_debug("%s: for %llu schedule op %d on "
1328                                  "replacement disc %d\n",
1329                                 __func__, (unsigned long long)sh->sector,
1330                                 rbi->bi_opf, i);
1331                         atomic_inc(&sh->count);
1332                         if (sh != head_sh)
1333                                 atomic_inc(&head_sh->count);
1334                         if (use_new_offset(conf, sh))
1335                                 rbi->bi_iter.bi_sector = (sh->sector
1336                                                   + rrdev->new_data_offset);
1337                         else
1338                                 rbi->bi_iter.bi_sector = (sh->sector
1339                                                   + rrdev->data_offset);
1340                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1341                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1342                         sh->dev[i].rvec.bv_page = sh->dev[i].page;
1343                         rbi->bi_vcnt = 1;
1344                         rbi->bi_io_vec[0].bv_len = RAID5_STRIPE_SIZE(conf);
1345                         rbi->bi_io_vec[0].bv_offset = sh->dev[i].offset;
1346                         rbi->bi_iter.bi_size = RAID5_STRIPE_SIZE(conf);
1347                         /*
1348                          * If this is discard request, set bi_vcnt 0. We don't
1349                          * want to confuse SCSI because SCSI will replace payload
1350                          */
1351                         if (op == REQ_OP_DISCARD)
1352                                 rbi->bi_vcnt = 0;
1353                         if (conf->mddev->gendisk)
1354                                 trace_block_bio_remap(rbi,
1355                                                 disk_devt(conf->mddev->gendisk),
1356                                                 sh->dev[i].sector);
1357                         if (should_defer && op_is_write(op))
1358                                 bio_list_add(&pending_bios, rbi);
1359                         else
1360                                 submit_bio_noacct(rbi);
1361                 }
1362                 if (!rdev && !rrdev) {
1363                         if (op_is_write(op))
1364                                 set_bit(STRIPE_DEGRADED, &sh->state);
1365                         pr_debug("skip op %d on disc %d for sector %llu\n",
1366                                 bi->bi_opf, i, (unsigned long long)sh->sector);
1367                         clear_bit(R5_LOCKED, &sh->dev[i].flags);
1368                         set_bit(STRIPE_HANDLE, &sh->state);
1369                 }
1370
1371                 if (!head_sh->batch_head)
1372                         continue;
1373                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1374                                       batch_list);
1375                 if (sh != head_sh)
1376                         goto again;
1377         }
1378
1379         if (should_defer && !bio_list_empty(&pending_bios))
1380                 defer_issue_bios(conf, head_sh->sector, &pending_bios);
1381 }
1382
1383 static struct dma_async_tx_descriptor *
1384 async_copy_data(int frombio, struct bio *bio, struct page **page,
1385         unsigned int poff, sector_t sector, struct dma_async_tx_descriptor *tx,
1386         struct stripe_head *sh, int no_skipcopy)
1387 {
1388         struct bio_vec bvl;
1389         struct bvec_iter iter;
1390         struct page *bio_page;
1391         int page_offset;
1392         struct async_submit_ctl submit;
1393         enum async_tx_flags flags = 0;
1394         struct r5conf *conf = sh->raid_conf;
1395
1396         if (bio->bi_iter.bi_sector >= sector)
1397                 page_offset = (signed)(bio->bi_iter.bi_sector - sector) * 512;
1398         else
1399                 page_offset = (signed)(sector - bio->bi_iter.bi_sector) * -512;
1400
1401         if (frombio)
1402                 flags |= ASYNC_TX_FENCE;
1403         init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
1404
1405         bio_for_each_segment(bvl, bio, iter) {
1406                 int len = bvl.bv_len;
1407                 int clen;
1408                 int b_offset = 0;
1409
1410                 if (page_offset < 0) {
1411                         b_offset = -page_offset;
1412                         page_offset += b_offset;
1413                         len -= b_offset;
1414                 }
1415
1416                 if (len > 0 && page_offset + len > RAID5_STRIPE_SIZE(conf))
1417                         clen = RAID5_STRIPE_SIZE(conf) - page_offset;
1418                 else
1419                         clen = len;
1420
1421                 if (clen > 0) {
1422                         b_offset += bvl.bv_offset;
1423                         bio_page = bvl.bv_page;
1424                         if (frombio) {
1425                                 if (conf->skip_copy &&
1426                                     b_offset == 0 && page_offset == 0 &&
1427                                     clen == RAID5_STRIPE_SIZE(conf) &&
1428                                     !no_skipcopy)
1429                                         *page = bio_page;
1430                                 else
1431                                         tx = async_memcpy(*page, bio_page, page_offset + poff,
1432                                                   b_offset, clen, &submit);
1433                         } else
1434                                 tx = async_memcpy(bio_page, *page, b_offset,
1435                                                   page_offset + poff, clen, &submit);
1436                 }
1437                 /* chain the operations */
1438                 submit.depend_tx = tx;
1439
1440                 if (clen < len) /* hit end of page */
1441                         break;
1442                 page_offset +=  len;
1443         }
1444
1445         return tx;
1446 }
1447
1448 static void ops_complete_biofill(void *stripe_head_ref)
1449 {
1450         struct stripe_head *sh = stripe_head_ref;
1451         int i;
1452         struct r5conf *conf = sh->raid_conf;
1453
1454         pr_debug("%s: stripe %llu\n", __func__,
1455                 (unsigned long long)sh->sector);
1456
1457         /* clear completed biofills */
1458         for (i = sh->disks; i--; ) {
1459                 struct r5dev *dev = &sh->dev[i];
1460
1461                 /* acknowledge completion of a biofill operation */
1462                 /* and check if we need to reply to a read request,
1463                  * new R5_Wantfill requests are held off until
1464                  * !STRIPE_BIOFILL_RUN
1465                  */
1466                 if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
1467                         struct bio *rbi, *rbi2;
1468
1469                         BUG_ON(!dev->read);
1470                         rbi = dev->read;
1471                         dev->read = NULL;
1472                         while (rbi && rbi->bi_iter.bi_sector <
1473                                 dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1474                                 rbi2 = r5_next_bio(conf, rbi, dev->sector);
1475                                 bio_endio(rbi);
1476                                 rbi = rbi2;
1477                         }
1478                 }
1479         }
1480         clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
1481
1482         set_bit(STRIPE_HANDLE, &sh->state);
1483         raid5_release_stripe(sh);
1484 }
1485
1486 static void ops_run_biofill(struct stripe_head *sh)
1487 {
1488         struct dma_async_tx_descriptor *tx = NULL;
1489         struct async_submit_ctl submit;
1490         int i;
1491         struct r5conf *conf = sh->raid_conf;
1492
1493         BUG_ON(sh->batch_head);
1494         pr_debug("%s: stripe %llu\n", __func__,
1495                 (unsigned long long)sh->sector);
1496
1497         for (i = sh->disks; i--; ) {
1498                 struct r5dev *dev = &sh->dev[i];
1499                 if (test_bit(R5_Wantfill, &dev->flags)) {
1500                         struct bio *rbi;
1501                         spin_lock_irq(&sh->stripe_lock);
1502                         dev->read = rbi = dev->toread;
1503                         dev->toread = NULL;
1504                         spin_unlock_irq(&sh->stripe_lock);
1505                         while (rbi && rbi->bi_iter.bi_sector <
1506                                 dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1507                                 tx = async_copy_data(0, rbi, &dev->page,
1508                                                      dev->offset,
1509                                                      dev->sector, tx, sh, 0);
1510                                 rbi = r5_next_bio(conf, rbi, dev->sector);
1511                         }
1512                 }
1513         }
1514
1515         atomic_inc(&sh->count);
1516         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
1517         async_trigger_callback(&submit);
1518 }
1519
1520 static void mark_target_uptodate(struct stripe_head *sh, int target)
1521 {
1522         struct r5dev *tgt;
1523
1524         if (target < 0)
1525                 return;
1526
1527         tgt = &sh->dev[target];
1528         set_bit(R5_UPTODATE, &tgt->flags);
1529         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1530         clear_bit(R5_Wantcompute, &tgt->flags);
1531 }
1532
1533 static void ops_complete_compute(void *stripe_head_ref)
1534 {
1535         struct stripe_head *sh = stripe_head_ref;
1536
1537         pr_debug("%s: stripe %llu\n", __func__,
1538                 (unsigned long long)sh->sector);
1539
1540         /* mark the computed target(s) as uptodate */
1541         mark_target_uptodate(sh, sh->ops.target);
1542         mark_target_uptodate(sh, sh->ops.target2);
1543
1544         clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
1545         if (sh->check_state == check_state_compute_run)
1546                 sh->check_state = check_state_compute_result;
1547         set_bit(STRIPE_HANDLE, &sh->state);
1548         raid5_release_stripe(sh);
1549 }
1550
1551 /* return a pointer to the address conversion region of the scribble buffer */
1552 static struct page **to_addr_page(struct raid5_percpu *percpu, int i)
1553 {
1554         return percpu->scribble + i * percpu->scribble_obj_size;
1555 }
1556
1557 /* return a pointer to the address conversion region of the scribble buffer */
1558 static addr_conv_t *to_addr_conv(struct stripe_head *sh,
1559                                  struct raid5_percpu *percpu, int i)
1560 {
1561         return (void *) (to_addr_page(percpu, i) + sh->disks + 2);
1562 }
1563
1564 /*
1565  * Return a pointer to record offset address.
1566  */
1567 static unsigned int *
1568 to_addr_offs(struct stripe_head *sh, struct raid5_percpu *percpu)
1569 {
1570         return (unsigned int *) (to_addr_conv(sh, percpu, 0) + sh->disks + 2);
1571 }
1572
1573 static struct dma_async_tx_descriptor *
1574 ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
1575 {
1576         int disks = sh->disks;
1577         struct page **xor_srcs = to_addr_page(percpu, 0);
1578         unsigned int *off_srcs = to_addr_offs(sh, percpu);
1579         int target = sh->ops.target;
1580         struct r5dev *tgt = &sh->dev[target];
1581         struct page *xor_dest = tgt->page;
1582         unsigned int off_dest = tgt->offset;
1583         int count = 0;
1584         struct dma_async_tx_descriptor *tx;
1585         struct async_submit_ctl submit;
1586         int i;
1587
1588         BUG_ON(sh->batch_head);
1589
1590         pr_debug("%s: stripe %llu block: %d\n",
1591                 __func__, (unsigned long long)sh->sector, target);
1592         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1593
1594         for (i = disks; i--; ) {
1595                 if (i != target) {
1596                         off_srcs[count] = sh->dev[i].offset;
1597                         xor_srcs[count++] = sh->dev[i].page;
1598                 }
1599         }
1600
1601         atomic_inc(&sh->count);
1602
1603         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
1604                           ops_complete_compute, sh, to_addr_conv(sh, percpu, 0));
1605         if (unlikely(count == 1))
1606                 tx = async_memcpy(xor_dest, xor_srcs[0], off_dest, off_srcs[0],
1607                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1608         else
1609                 tx = async_xor_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
1610                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1611
1612         return tx;
1613 }
1614
1615 /* set_syndrome_sources - populate source buffers for gen_syndrome
1616  * @srcs - (struct page *) array of size sh->disks
1617  * @offs - (unsigned int) array of offset for each page
1618  * @sh - stripe_head to parse
1619  *
1620  * Populates srcs in proper layout order for the stripe and returns the
1621  * 'count' of sources to be used in a call to async_gen_syndrome.  The P
1622  * destination buffer is recorded in srcs[count] and the Q destination
1623  * is recorded in srcs[count+1]].
1624  */
1625 static int set_syndrome_sources(struct page **srcs,
1626                                 unsigned int *offs,
1627                                 struct stripe_head *sh,
1628                                 int srctype)
1629 {
1630         int disks = sh->disks;
1631         int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
1632         int d0_idx = raid6_d0(sh);
1633         int count;
1634         int i;
1635
1636         for (i = 0; i < disks; i++)
1637                 srcs[i] = NULL;
1638
1639         count = 0;
1640         i = d0_idx;
1641         do {
1642                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1643                 struct r5dev *dev = &sh->dev[i];
1644
1645                 if (i == sh->qd_idx || i == sh->pd_idx ||
1646                     (srctype == SYNDROME_SRC_ALL) ||
1647                     (srctype == SYNDROME_SRC_WANT_DRAIN &&
1648                      (test_bit(R5_Wantdrain, &dev->flags) ||
1649                       test_bit(R5_InJournal, &dev->flags))) ||
1650                     (srctype == SYNDROME_SRC_WRITTEN &&
1651                      (dev->written ||
1652                       test_bit(R5_InJournal, &dev->flags)))) {
1653                         if (test_bit(R5_InJournal, &dev->flags))
1654                                 srcs[slot] = sh->dev[i].orig_page;
1655                         else
1656                                 srcs[slot] = sh->dev[i].page;
1657                         /*
1658                          * For R5_InJournal, PAGE_SIZE must be 4KB and will
1659                          * not shared page. In that case, dev[i].offset
1660                          * is 0.
1661                          */
1662                         offs[slot] = sh->dev[i].offset;
1663                 }
1664                 i = raid6_next_disk(i, disks);
1665         } while (i != d0_idx);
1666
1667         return syndrome_disks;
1668 }
1669
1670 static struct dma_async_tx_descriptor *
1671 ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
1672 {
1673         int disks = sh->disks;
1674         struct page **blocks = to_addr_page(percpu, 0);
1675         unsigned int *offs = to_addr_offs(sh, percpu);
1676         int target;
1677         int qd_idx = sh->qd_idx;
1678         struct dma_async_tx_descriptor *tx;
1679         struct async_submit_ctl submit;
1680         struct r5dev *tgt;
1681         struct page *dest;
1682         unsigned int dest_off;
1683         int i;
1684         int count;
1685
1686         BUG_ON(sh->batch_head);
1687         if (sh->ops.target < 0)
1688                 target = sh->ops.target2;
1689         else if (sh->ops.target2 < 0)
1690                 target = sh->ops.target;
1691         else
1692                 /* we should only have one valid target */
1693                 BUG();
1694         BUG_ON(target < 0);
1695         pr_debug("%s: stripe %llu block: %d\n",
1696                 __func__, (unsigned long long)sh->sector, target);
1697
1698         tgt = &sh->dev[target];
1699         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1700         dest = tgt->page;
1701         dest_off = tgt->offset;
1702
1703         atomic_inc(&sh->count);
1704
1705         if (target == qd_idx) {
1706                 count = set_syndrome_sources(blocks, offs, sh, SYNDROME_SRC_ALL);
1707                 blocks[count] = NULL; /* regenerating p is not necessary */
1708                 BUG_ON(blocks[count+1] != dest); /* q should already be set */
1709                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1710                                   ops_complete_compute, sh,
1711                                   to_addr_conv(sh, percpu, 0));
1712                 tx = async_gen_syndrome(blocks, offs, count+2,
1713                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1714         } else {
1715                 /* Compute any data- or p-drive using XOR */
1716                 count = 0;
1717                 for (i = disks; i-- ; ) {
1718                         if (i == target || i == qd_idx)
1719                                 continue;
1720                         offs[count] = sh->dev[i].offset;
1721                         blocks[count++] = sh->dev[i].page;
1722                 }
1723
1724                 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1725                                   NULL, ops_complete_compute, sh,
1726                                   to_addr_conv(sh, percpu, 0));
1727                 tx = async_xor_offs(dest, dest_off, blocks, offs, count,
1728                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1729         }
1730
1731         return tx;
1732 }
1733
1734 static struct dma_async_tx_descriptor *
1735 ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
1736 {
1737         int i, count, disks = sh->disks;
1738         int syndrome_disks = sh->ddf_layout ? disks : disks-2;
1739         int d0_idx = raid6_d0(sh);
1740         int faila = -1, failb = -1;
1741         int target = sh->ops.target;
1742         int target2 = sh->ops.target2;
1743         struct r5dev *tgt = &sh->dev[target];
1744         struct r5dev *tgt2 = &sh->dev[target2];
1745         struct dma_async_tx_descriptor *tx;
1746         struct page **blocks = to_addr_page(percpu, 0);
1747         unsigned int *offs = to_addr_offs(sh, percpu);
1748         struct async_submit_ctl submit;
1749
1750         BUG_ON(sh->batch_head);
1751         pr_debug("%s: stripe %llu block1: %d block2: %d\n",
1752                  __func__, (unsigned long long)sh->sector, target, target2);
1753         BUG_ON(target < 0 || target2 < 0);
1754         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1755         BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
1756
1757         /* we need to open-code set_syndrome_sources to handle the
1758          * slot number conversion for 'faila' and 'failb'
1759          */
1760         for (i = 0; i < disks ; i++) {
1761                 offs[i] = 0;
1762                 blocks[i] = NULL;
1763         }
1764         count = 0;
1765         i = d0_idx;
1766         do {
1767                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1768
1769                 offs[slot] = sh->dev[i].offset;
1770                 blocks[slot] = sh->dev[i].page;
1771
1772                 if (i == target)
1773                         faila = slot;
1774                 if (i == target2)
1775                         failb = slot;
1776                 i = raid6_next_disk(i, disks);
1777         } while (i != d0_idx);
1778
1779         BUG_ON(faila == failb);
1780         if (failb < faila)
1781                 swap(faila, failb);
1782         pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
1783                  __func__, (unsigned long long)sh->sector, faila, failb);
1784
1785         atomic_inc(&sh->count);
1786
1787         if (failb == syndrome_disks+1) {
1788                 /* Q disk is one of the missing disks */
1789                 if (faila == syndrome_disks) {
1790                         /* Missing P+Q, just recompute */
1791                         init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1792                                           ops_complete_compute, sh,
1793                                           to_addr_conv(sh, percpu, 0));
1794                         return async_gen_syndrome(blocks, offs, syndrome_disks+2,
1795                                                   RAID5_STRIPE_SIZE(sh->raid_conf),
1796                                                   &submit);
1797                 } else {
1798                         struct page *dest;
1799                         unsigned int dest_off;
1800                         int data_target;
1801                         int qd_idx = sh->qd_idx;
1802
1803                         /* Missing D+Q: recompute D from P, then recompute Q */
1804                         if (target == qd_idx)
1805                                 data_target = target2;
1806                         else
1807                                 data_target = target;
1808
1809                         count = 0;
1810                         for (i = disks; i-- ; ) {
1811                                 if (i == data_target || i == qd_idx)
1812                                         continue;
1813                                 offs[count] = sh->dev[i].offset;
1814                                 blocks[count++] = sh->dev[i].page;
1815                         }
1816                         dest = sh->dev[data_target].page;
1817                         dest_off = sh->dev[data_target].offset;
1818                         init_async_submit(&submit,
1819                                           ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1820                                           NULL, NULL, NULL,
1821                                           to_addr_conv(sh, percpu, 0));
1822                         tx = async_xor_offs(dest, dest_off, blocks, offs, count,
1823                                        RAID5_STRIPE_SIZE(sh->raid_conf),
1824                                        &submit);
1825
1826                         count = set_syndrome_sources(blocks, offs, sh, SYNDROME_SRC_ALL);
1827                         init_async_submit(&submit, ASYNC_TX_FENCE, tx,
1828                                           ops_complete_compute, sh,
1829                                           to_addr_conv(sh, percpu, 0));
1830                         return async_gen_syndrome(blocks, offs, count+2,
1831                                                   RAID5_STRIPE_SIZE(sh->raid_conf),
1832                                                   &submit);
1833                 }
1834         } else {
1835                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1836                                   ops_complete_compute, sh,
1837                                   to_addr_conv(sh, percpu, 0));
1838                 if (failb == syndrome_disks) {
1839                         /* We're missing D+P. */
1840                         return async_raid6_datap_recov(syndrome_disks+2,
1841                                                 RAID5_STRIPE_SIZE(sh->raid_conf),
1842                                                 faila,
1843                                                 blocks, offs, &submit);
1844                 } else {
1845                         /* We're missing D+D. */
1846                         return async_raid6_2data_recov(syndrome_disks+2,
1847                                                 RAID5_STRIPE_SIZE(sh->raid_conf),
1848                                                 faila, failb,
1849                                                 blocks, offs, &submit);
1850                 }
1851         }
1852 }
1853
1854 static void ops_complete_prexor(void *stripe_head_ref)
1855 {
1856         struct stripe_head *sh = stripe_head_ref;
1857
1858         pr_debug("%s: stripe %llu\n", __func__,
1859                 (unsigned long long)sh->sector);
1860
1861         if (r5c_is_writeback(sh->raid_conf->log))
1862                 /*
1863                  * raid5-cache write back uses orig_page during prexor.
1864                  * After prexor, it is time to free orig_page
1865                  */
1866                 r5c_release_extra_page(sh);
1867 }
1868
1869 static struct dma_async_tx_descriptor *
1870 ops_run_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
1871                 struct dma_async_tx_descriptor *tx)
1872 {
1873         int disks = sh->disks;
1874         struct page **xor_srcs = to_addr_page(percpu, 0);
1875         unsigned int *off_srcs = to_addr_offs(sh, percpu);
1876         int count = 0, pd_idx = sh->pd_idx, i;
1877         struct async_submit_ctl submit;
1878
1879         /* existing parity data subtracted */
1880         unsigned int off_dest = off_srcs[count] = sh->dev[pd_idx].offset;
1881         struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1882
1883         BUG_ON(sh->batch_head);
1884         pr_debug("%s: stripe %llu\n", __func__,
1885                 (unsigned long long)sh->sector);
1886
1887         for (i = disks; i--; ) {
1888                 struct r5dev *dev = &sh->dev[i];
1889                 /* Only process blocks that are known to be uptodate */
1890                 if (test_bit(R5_InJournal, &dev->flags)) {
1891                         /*
1892                          * For this case, PAGE_SIZE must be equal to 4KB and
1893                          * page offset is zero.
1894                          */
1895                         off_srcs[count] = dev->offset;
1896                         xor_srcs[count++] = dev->orig_page;
1897                 } else if (test_bit(R5_Wantdrain, &dev->flags)) {
1898                         off_srcs[count] = dev->offset;
1899                         xor_srcs[count++] = dev->page;
1900                 }
1901         }
1902
1903         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1904                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1905         tx = async_xor_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
1906                         RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1907
1908         return tx;
1909 }
1910
1911 static struct dma_async_tx_descriptor *
1912 ops_run_prexor6(struct stripe_head *sh, struct raid5_percpu *percpu,
1913                 struct dma_async_tx_descriptor *tx)
1914 {
1915         struct page **blocks = to_addr_page(percpu, 0);
1916         unsigned int *offs = to_addr_offs(sh, percpu);
1917         int count;
1918         struct async_submit_ctl submit;
1919
1920         pr_debug("%s: stripe %llu\n", __func__,
1921                 (unsigned long long)sh->sector);
1922
1923         count = set_syndrome_sources(blocks, offs, sh, SYNDROME_SRC_WANT_DRAIN);
1924
1925         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_PQ_XOR_DST, tx,
1926                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1927         tx = async_gen_syndrome(blocks, offs, count+2,
1928                         RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1929
1930         return tx;
1931 }
1932
1933 static struct dma_async_tx_descriptor *
1934 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1935 {
1936         struct r5conf *conf = sh->raid_conf;
1937         int disks = sh->disks;
1938         int i;
1939         struct stripe_head *head_sh = sh;
1940
1941         pr_debug("%s: stripe %llu\n", __func__,
1942                 (unsigned long long)sh->sector);
1943
1944         for (i = disks; i--; ) {
1945                 struct r5dev *dev;
1946                 struct bio *chosen;
1947
1948                 sh = head_sh;
1949                 if (test_and_clear_bit(R5_Wantdrain, &head_sh->dev[i].flags)) {
1950                         struct bio *wbi;
1951
1952 again:
1953                         dev = &sh->dev[i];
1954                         /*
1955                          * clear R5_InJournal, so when rewriting a page in
1956                          * journal, it is not skipped by r5l_log_stripe()
1957                          */
1958                         clear_bit(R5_InJournal, &dev->flags);
1959                         spin_lock_irq(&sh->stripe_lock);
1960                         chosen = dev->towrite;
1961                         dev->towrite = NULL;
1962                         sh->overwrite_disks = 0;
1963                         BUG_ON(dev->written);
1964                         wbi = dev->written = chosen;
1965                         spin_unlock_irq(&sh->stripe_lock);
1966                         WARN_ON(dev->page != dev->orig_page);
1967
1968                         while (wbi && wbi->bi_iter.bi_sector <
1969                                 dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1970                                 if (wbi->bi_opf & REQ_FUA)
1971                                         set_bit(R5_WantFUA, &dev->flags);
1972                                 if (wbi->bi_opf & REQ_SYNC)
1973                                         set_bit(R5_SyncIO, &dev->flags);
1974                                 if (bio_op(wbi) == REQ_OP_DISCARD)
1975                                         set_bit(R5_Discard, &dev->flags);
1976                                 else {
1977                                         tx = async_copy_data(1, wbi, &dev->page,
1978                                                              dev->offset,
1979                                                              dev->sector, tx, sh,
1980                                                              r5c_is_writeback(conf->log));
1981                                         if (dev->page != dev->orig_page &&
1982                                             !r5c_is_writeback(conf->log)) {
1983                                                 set_bit(R5_SkipCopy, &dev->flags);
1984                                                 clear_bit(R5_UPTODATE, &dev->flags);
1985                                                 clear_bit(R5_OVERWRITE, &dev->flags);
1986                                         }
1987                                 }
1988                                 wbi = r5_next_bio(conf, wbi, dev->sector);
1989                         }
1990
1991                         if (head_sh->batch_head) {
1992                                 sh = list_first_entry(&sh->batch_list,
1993                                                       struct stripe_head,
1994                                                       batch_list);
1995                                 if (sh == head_sh)
1996                                         continue;
1997                                 goto again;
1998                         }
1999                 }
2000         }
2001
2002         return tx;
2003 }
2004
2005 static void ops_complete_reconstruct(void *stripe_head_ref)
2006 {
2007         struct stripe_head *sh = stripe_head_ref;
2008         int disks = sh->disks;
2009         int pd_idx = sh->pd_idx;
2010         int qd_idx = sh->qd_idx;
2011         int i;
2012         bool fua = false, sync = false, discard = false;
2013
2014         pr_debug("%s: stripe %llu\n", __func__,
2015                 (unsigned long long)sh->sector);
2016
2017         for (i = disks; i--; ) {
2018                 fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
2019                 sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
2020                 discard |= test_bit(R5_Discard, &sh->dev[i].flags);
2021         }
2022
2023         for (i = disks; i--; ) {
2024                 struct r5dev *dev = &sh->dev[i];
2025
2026                 if (dev->written || i == pd_idx || i == qd_idx) {
2027                         if (!discard && !test_bit(R5_SkipCopy, &dev->flags)) {
2028                                 set_bit(R5_UPTODATE, &dev->flags);
2029                                 if (test_bit(STRIPE_EXPAND_READY, &sh->state))
2030                                         set_bit(R5_Expanded, &dev->flags);
2031                         }
2032                         if (fua)
2033                                 set_bit(R5_WantFUA, &dev->flags);
2034                         if (sync)
2035                                 set_bit(R5_SyncIO, &dev->flags);
2036                 }
2037         }
2038
2039         if (sh->reconstruct_state == reconstruct_state_drain_run)
2040                 sh->reconstruct_state = reconstruct_state_drain_result;
2041         else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
2042                 sh->reconstruct_state = reconstruct_state_prexor_drain_result;
2043         else {
2044                 BUG_ON(sh->reconstruct_state != reconstruct_state_run);
2045                 sh->reconstruct_state = reconstruct_state_result;
2046         }
2047
2048         set_bit(STRIPE_HANDLE, &sh->state);
2049         raid5_release_stripe(sh);
2050 }
2051
2052 static void
2053 ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
2054                      struct dma_async_tx_descriptor *tx)
2055 {
2056         int disks = sh->disks;
2057         struct page **xor_srcs;
2058         unsigned int *off_srcs;
2059         struct async_submit_ctl submit;
2060         int count, pd_idx = sh->pd_idx, i;
2061         struct page *xor_dest;
2062         unsigned int off_dest;
2063         int prexor = 0;
2064         unsigned long flags;
2065         int j = 0;
2066         struct stripe_head *head_sh = sh;
2067         int last_stripe;
2068
2069         pr_debug("%s: stripe %llu\n", __func__,
2070                 (unsigned long long)sh->sector);
2071
2072         for (i = 0; i < sh->disks; i++) {
2073                 if (pd_idx == i)
2074                         continue;
2075                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
2076                         break;
2077         }
2078         if (i >= sh->disks) {
2079                 atomic_inc(&sh->count);
2080                 set_bit(R5_Discard, &sh->dev[pd_idx].flags);
2081                 ops_complete_reconstruct(sh);
2082                 return;
2083         }
2084 again:
2085         count = 0;
2086         xor_srcs = to_addr_page(percpu, j);
2087         off_srcs = to_addr_offs(sh, percpu);
2088         /* check if prexor is active which means only process blocks
2089          * that are part of a read-modify-write (written)
2090          */
2091         if (head_sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
2092                 prexor = 1;
2093                 off_dest = off_srcs[count] = sh->dev[pd_idx].offset;
2094                 xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
2095                 for (i = disks; i--; ) {
2096                         struct r5dev *dev = &sh->dev[i];
2097                         if (head_sh->dev[i].written ||
2098                             test_bit(R5_InJournal, &head_sh->dev[i].flags)) {
2099                                 off_srcs[count] = dev->offset;
2100                                 xor_srcs[count++] = dev->page;
2101                         }
2102                 }
2103         } else {
2104                 xor_dest = sh->dev[pd_idx].page;
2105                 off_dest = sh->dev[pd_idx].offset;
2106                 for (i = disks; i--; ) {
2107                         struct r5dev *dev = &sh->dev[i];
2108                         if (i != pd_idx) {
2109                                 off_srcs[count] = dev->offset;
2110                                 xor_srcs[count++] = dev->page;
2111                         }
2112                 }
2113         }
2114
2115         /* 1/ if we prexor'd then the dest is reused as a source
2116          * 2/ if we did not prexor then we are redoing the parity
2117          * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
2118          * for the synchronous xor case
2119          */
2120         last_stripe = !head_sh->batch_head ||
2121                 list_first_entry(&sh->batch_list,
2122                                  struct stripe_head, batch_list) == head_sh;
2123         if (last_stripe) {
2124                 flags = ASYNC_TX_ACK |
2125                         (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
2126
2127                 atomic_inc(&head_sh->count);
2128                 init_async_submit(&submit, flags, tx, ops_complete_reconstruct, head_sh,
2129                                   to_addr_conv(sh, percpu, j));
2130         } else {
2131                 flags = prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST;
2132                 init_async_submit(&submit, flags, tx, NULL, NULL,
2133                                   to_addr_conv(sh, percpu, j));
2134         }
2135
2136         if (unlikely(count == 1))
2137                 tx = async_memcpy(xor_dest, xor_srcs[0], off_dest, off_srcs[0],
2138                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
2139         else
2140                 tx = async_xor_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
2141                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
2142         if (!last_stripe) {
2143                 j++;
2144                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
2145                                       batch_list);
2146                 goto again;
2147         }
2148 }
2149
2150 static void
2151 ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
2152                      struct dma_async_tx_descriptor *tx)
2153 {
2154         struct async_submit_ctl submit;
2155         struct page **blocks;
2156         unsigned int *offs;
2157         int count, i, j = 0;
2158         struct stripe_head *head_sh = sh;
2159         int last_stripe;
2160         int synflags;
2161         unsigned long txflags;
2162
2163         pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
2164
2165         for (i = 0; i < sh->disks; i++) {
2166                 if (sh->pd_idx == i || sh->qd_idx == i)
2167                         continue;
2168                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
2169                         break;
2170         }
2171         if (i >= sh->disks) {
2172                 atomic_inc(&sh->count);
2173                 set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
2174                 set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
2175                 ops_complete_reconstruct(sh);
2176                 return;
2177         }
2178
2179 again:
2180         blocks = to_addr_page(percpu, j);
2181         offs = to_addr_offs(sh, percpu);
2182
2183         if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
2184                 synflags = SYNDROME_SRC_WRITTEN;
2185                 txflags = ASYNC_TX_ACK | ASYNC_TX_PQ_XOR_DST;
2186         } else {
2187                 synflags = SYNDROME_SRC_ALL;
2188                 txflags = ASYNC_TX_ACK;
2189         }
2190
2191         count = set_syndrome_sources(blocks, offs, sh, synflags);
2192         last_stripe = !head_sh->batch_head ||
2193                 list_first_entry(&sh->batch_list,
2194                                  struct stripe_head, batch_list) == head_sh;
2195
2196         if (last_stripe) {
2197                 atomic_inc(&head_sh->count);
2198                 init_async_submit(&submit, txflags, tx, ops_complete_reconstruct,
2199                                   head_sh, to_addr_conv(sh, percpu, j));
2200         } else
2201                 init_async_submit(&submit, 0, tx, NULL, NULL,
2202                                   to_addr_conv(sh, percpu, j));
2203         tx = async_gen_syndrome(blocks, offs, count+2,
2204                         RAID5_STRIPE_SIZE(sh->raid_conf),  &submit);
2205         if (!last_stripe) {
2206                 j++;
2207                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
2208                                       batch_list);
2209                 goto again;
2210         }
2211 }
2212
2213 static void ops_complete_check(void *stripe_head_ref)
2214 {
2215         struct stripe_head *sh = stripe_head_ref;
2216
2217         pr_debug("%s: stripe %llu\n", __func__,
2218                 (unsigned long long)sh->sector);
2219
2220         sh->check_state = check_state_check_result;
2221         set_bit(STRIPE_HANDLE, &sh->state);
2222         raid5_release_stripe(sh);
2223 }
2224
2225 static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
2226 {
2227         int disks = sh->disks;
2228         int pd_idx = sh->pd_idx;
2229         int qd_idx = sh->qd_idx;
2230         struct page *xor_dest;
2231         unsigned int off_dest;
2232         struct page **xor_srcs = to_addr_page(percpu, 0);
2233         unsigned int *off_srcs = to_addr_offs(sh, percpu);
2234         struct dma_async_tx_descriptor *tx;
2235         struct async_submit_ctl submit;
2236         int count;
2237         int i;
2238
2239         pr_debug("%s: stripe %llu\n", __func__,
2240                 (unsigned long long)sh->sector);
2241
2242         BUG_ON(sh->batch_head);
2243         count = 0;
2244         xor_dest = sh->dev[pd_idx].page;
2245         off_dest = sh->dev[pd_idx].offset;
2246         off_srcs[count] = off_dest;
2247         xor_srcs[count++] = xor_dest;
2248         for (i = disks; i--; ) {
2249                 if (i == pd_idx || i == qd_idx)
2250                         continue;
2251                 off_srcs[count] = sh->dev[i].offset;
2252                 xor_srcs[count++] = sh->dev[i].page;
2253         }
2254
2255         init_async_submit(&submit, 0, NULL, NULL, NULL,
2256                           to_addr_conv(sh, percpu, 0));
2257         tx = async_xor_val_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
2258                            RAID5_STRIPE_SIZE(sh->raid_conf),
2259                            &sh->ops.zero_sum_result, &submit);
2260
2261         atomic_inc(&sh->count);
2262         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
2263         tx = async_trigger_callback(&submit);
2264 }
2265
2266 static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
2267 {
2268         struct page **srcs = to_addr_page(percpu, 0);
2269         unsigned int *offs = to_addr_offs(sh, percpu);
2270         struct async_submit_ctl submit;
2271         int count;
2272
2273         pr_debug("%s: stripe %llu checkp: %d\n", __func__,
2274                 (unsigned long long)sh->sector, checkp);
2275
2276         BUG_ON(sh->batch_head);
2277         count = set_syndrome_sources(srcs, offs, sh, SYNDROME_SRC_ALL);
2278         if (!checkp)
2279                 srcs[count] = NULL;
2280
2281         atomic_inc(&sh->count);
2282         init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
2283                           sh, to_addr_conv(sh, percpu, 0));
2284         async_syndrome_val(srcs, offs, count+2,
2285                            RAID5_STRIPE_SIZE(sh->raid_conf),
2286                            &sh->ops.zero_sum_result, percpu->spare_page, 0, &submit);
2287 }
2288
2289 static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
2290 {
2291         int overlap_clear = 0, i, disks = sh->disks;
2292         struct dma_async_tx_descriptor *tx = NULL;
2293         struct r5conf *conf = sh->raid_conf;
2294         int level = conf->level;
2295         struct raid5_percpu *percpu;
2296
2297         local_lock(&conf->percpu->lock);
2298         percpu = this_cpu_ptr(conf->percpu);
2299         if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
2300                 ops_run_biofill(sh);
2301                 overlap_clear++;
2302         }
2303
2304         if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
2305                 if (level < 6)
2306                         tx = ops_run_compute5(sh, percpu);
2307                 else {
2308                         if (sh->ops.target2 < 0 || sh->ops.target < 0)
2309                                 tx = ops_run_compute6_1(sh, percpu);
2310                         else
2311                                 tx = ops_run_compute6_2(sh, percpu);
2312                 }
2313                 /* terminate the chain if reconstruct is not set to be run */
2314                 if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
2315                         async_tx_ack(tx);
2316         }
2317
2318         if (test_bit(STRIPE_OP_PREXOR, &ops_request)) {
2319                 if (level < 6)
2320                         tx = ops_run_prexor5(sh, percpu, tx);
2321                 else
2322                         tx = ops_run_prexor6(sh, percpu, tx);
2323         }
2324
2325         if (test_bit(STRIPE_OP_PARTIAL_PARITY, &ops_request))
2326                 tx = ops_run_partial_parity(sh, percpu, tx);
2327
2328         if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
2329                 tx = ops_run_biodrain(sh, tx);
2330                 overlap_clear++;
2331         }
2332
2333         if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
2334                 if (level < 6)
2335                         ops_run_reconstruct5(sh, percpu, tx);
2336                 else
2337                         ops_run_reconstruct6(sh, percpu, tx);
2338         }
2339
2340         if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
2341                 if (sh->check_state == check_state_run)
2342                         ops_run_check_p(sh, percpu);
2343                 else if (sh->check_state == check_state_run_q)
2344                         ops_run_check_pq(sh, percpu, 0);
2345                 else if (sh->check_state == check_state_run_pq)
2346                         ops_run_check_pq(sh, percpu, 1);
2347                 else
2348                         BUG();
2349         }
2350
2351         if (overlap_clear && !sh->batch_head) {
2352                 for (i = disks; i--; ) {
2353                         struct r5dev *dev = &sh->dev[i];
2354                         if (test_and_clear_bit(R5_Overlap, &dev->flags))
2355                                 wake_up(&sh->raid_conf->wait_for_overlap);
2356                 }
2357         }
2358         local_unlock(&conf->percpu->lock);
2359 }
2360
2361 static void free_stripe(struct kmem_cache *sc, struct stripe_head *sh)
2362 {
2363 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2364         kfree(sh->pages);
2365 #endif
2366         if (sh->ppl_page)
2367                 __free_page(sh->ppl_page);
2368         kmem_cache_free(sc, sh);
2369 }
2370
2371 static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp,
2372         int disks, struct r5conf *conf)
2373 {
2374         struct stripe_head *sh;
2375
2376         sh = kmem_cache_zalloc(sc, gfp);
2377         if (sh) {
2378                 spin_lock_init(&sh->stripe_lock);
2379                 spin_lock_init(&sh->batch_lock);
2380                 INIT_LIST_HEAD(&sh->batch_list);
2381                 INIT_LIST_HEAD(&sh->lru);
2382                 INIT_LIST_HEAD(&sh->r5c);
2383                 INIT_LIST_HEAD(&sh->log_list);
2384                 atomic_set(&sh->count, 1);
2385                 sh->raid_conf = conf;
2386                 sh->log_start = MaxSector;
2387
2388                 if (raid5_has_ppl(conf)) {
2389                         sh->ppl_page = alloc_page(gfp);
2390                         if (!sh->ppl_page) {
2391                                 free_stripe(sc, sh);
2392                                 return NULL;
2393                         }
2394                 }
2395 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2396                 if (init_stripe_shared_pages(sh, conf, disks)) {
2397                         free_stripe(sc, sh);
2398                         return NULL;
2399                 }
2400 #endif
2401         }
2402         return sh;
2403 }
2404 static int grow_one_stripe(struct r5conf *conf, gfp_t gfp)
2405 {
2406         struct stripe_head *sh;
2407
2408         sh = alloc_stripe(conf->slab_cache, gfp, conf->pool_size, conf);
2409         if (!sh)
2410                 return 0;
2411
2412         if (grow_buffers(sh, gfp)) {
2413                 shrink_buffers(sh);
2414                 free_stripe(conf->slab_cache, sh);
2415                 return 0;
2416         }
2417         sh->hash_lock_index =
2418                 conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS;
2419         /* we just created an active stripe so... */
2420         atomic_inc(&conf->active_stripes);
2421
2422         raid5_release_stripe(sh);
2423         conf->max_nr_stripes++;
2424         return 1;
2425 }
2426
2427 static int grow_stripes(struct r5conf *conf, int num)
2428 {
2429         struct kmem_cache *sc;
2430         size_t namelen = sizeof(conf->cache_name[0]);
2431         int devs = max(conf->raid_disks, conf->previous_raid_disks);
2432
2433         if (conf->mddev->gendisk)
2434                 snprintf(conf->cache_name[0], namelen,
2435                         "raid%d-%s", conf->level, mdname(conf->mddev));
2436         else
2437                 snprintf(conf->cache_name[0], namelen,
2438                         "raid%d-%p", conf->level, conf->mddev);
2439         snprintf(conf->cache_name[1], namelen, "%.27s-alt", conf->cache_name[0]);
2440
2441         conf->active_name = 0;
2442         sc = kmem_cache_create(conf->cache_name[conf->active_name],
2443                                struct_size_t(struct stripe_head, dev, devs),
2444                                0, 0, NULL);
2445         if (!sc)
2446                 return 1;
2447         conf->slab_cache = sc;
2448         conf->pool_size = devs;
2449         while (num--)
2450                 if (!grow_one_stripe(conf, GFP_KERNEL))
2451                         return 1;
2452
2453         return 0;
2454 }
2455
2456 /**
2457  * scribble_alloc - allocate percpu scribble buffer for required size
2458  *                  of the scribble region
2459  * @percpu: from for_each_present_cpu() of the caller
2460  * @num: total number of disks in the array
2461  * @cnt: scribble objs count for required size of the scribble region
2462  *
2463  * The scribble buffer size must be enough to contain:
2464  * 1/ a struct page pointer for each device in the array +2
2465  * 2/ room to convert each entry in (1) to its corresponding dma
2466  *    (dma_map_page()) or page (page_address()) address.
2467  *
2468  * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
2469  * calculate over all devices (not just the data blocks), using zeros in place
2470  * of the P and Q blocks.
2471  */
2472 static int scribble_alloc(struct raid5_percpu *percpu,
2473                           int num, int cnt)
2474 {
2475         size_t obj_size =
2476                 sizeof(struct page *) * (num + 2) +
2477                 sizeof(addr_conv_t) * (num + 2) +
2478                 sizeof(unsigned int) * (num + 2);
2479         void *scribble;
2480
2481         /*
2482          * If here is in raid array suspend context, it is in memalloc noio
2483          * context as well, there is no potential recursive memory reclaim
2484          * I/Os with the GFP_KERNEL flag.
2485          */
2486         scribble = kvmalloc_array(cnt, obj_size, GFP_KERNEL);
2487         if (!scribble)
2488                 return -ENOMEM;
2489
2490         kvfree(percpu->scribble);
2491
2492         percpu->scribble = scribble;
2493         percpu->scribble_obj_size = obj_size;
2494         return 0;
2495 }
2496
2497 static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
2498 {
2499         unsigned long cpu;
2500         int err = 0;
2501
2502         /*
2503          * Never shrink. And mddev_suspend() could deadlock if this is called
2504          * from raid5d. In that case, scribble_disks and scribble_sectors
2505          * should equal to new_disks and new_sectors
2506          */
2507         if (conf->scribble_disks >= new_disks &&
2508             conf->scribble_sectors >= new_sectors)
2509                 return 0;
2510         mddev_suspend(conf->mddev);
2511         cpus_read_lock();
2512
2513         for_each_present_cpu(cpu) {
2514                 struct raid5_percpu *percpu;
2515
2516                 percpu = per_cpu_ptr(conf->percpu, cpu);
2517                 err = scribble_alloc(percpu, new_disks,
2518                                      new_sectors / RAID5_STRIPE_SECTORS(conf));
2519                 if (err)
2520                         break;
2521         }
2522
2523         cpus_read_unlock();
2524         mddev_resume(conf->mddev);
2525         if (!err) {
2526                 conf->scribble_disks = new_disks;
2527                 conf->scribble_sectors = new_sectors;
2528         }
2529         return err;
2530 }
2531
2532 static int resize_stripes(struct r5conf *conf, int newsize)
2533 {
2534         /* Make all the stripes able to hold 'newsize' devices.
2535          * New slots in each stripe get 'page' set to a new page.
2536          *
2537          * This happens in stages:
2538          * 1/ create a new kmem_cache and allocate the required number of
2539          *    stripe_heads.
2540          * 2/ gather all the old stripe_heads and transfer the pages across
2541          *    to the new stripe_heads.  This will have the side effect of
2542          *    freezing the array as once all stripe_heads have been collected,
2543          *    no IO will be possible.  Old stripe heads are freed once their
2544          *    pages have been transferred over, and the old kmem_cache is
2545          *    freed when all stripes are done.
2546          * 3/ reallocate conf->disks to be suitable bigger.  If this fails,
2547          *    we simple return a failure status - no need to clean anything up.
2548          * 4/ allocate new pages for the new slots in the new stripe_heads.
2549          *    If this fails, we don't bother trying the shrink the
2550          *    stripe_heads down again, we just leave them as they are.
2551          *    As each stripe_head is processed the new one is released into
2552          *    active service.
2553          *
2554          * Once step2 is started, we cannot afford to wait for a write,
2555          * so we use GFP_NOIO allocations.
2556          */
2557         struct stripe_head *osh, *nsh;
2558         LIST_HEAD(newstripes);
2559         struct disk_info *ndisks;
2560         int err = 0;
2561         struct kmem_cache *sc;
2562         int i;
2563         int hash, cnt;
2564
2565         md_allow_write(conf->mddev);
2566
2567         /* Step 1 */
2568         sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
2569                                struct_size_t(struct stripe_head, dev, newsize),
2570                                0, 0, NULL);
2571         if (!sc)
2572                 return -ENOMEM;
2573
2574         /* Need to ensure auto-resizing doesn't interfere */
2575         mutex_lock(&conf->cache_size_mutex);
2576
2577         for (i = conf->max_nr_stripes; i; i--) {
2578                 nsh = alloc_stripe(sc, GFP_KERNEL, newsize, conf);
2579                 if (!nsh)
2580                         break;
2581
2582                 list_add(&nsh->lru, &newstripes);
2583         }
2584         if (i) {
2585                 /* didn't get enough, give up */
2586                 while (!list_empty(&newstripes)) {
2587                         nsh = list_entry(newstripes.next, struct stripe_head, lru);
2588                         list_del(&nsh->lru);
2589                         free_stripe(sc, nsh);
2590                 }
2591                 kmem_cache_destroy(sc);
2592                 mutex_unlock(&conf->cache_size_mutex);
2593                 return -ENOMEM;
2594         }
2595         /* Step 2 - Must use GFP_NOIO now.
2596          * OK, we have enough stripes, start collecting inactive
2597          * stripes and copying them over
2598          */
2599         hash = 0;
2600         cnt = 0;
2601         list_for_each_entry(nsh, &newstripes, lru) {
2602                 lock_device_hash_lock(conf, hash);
2603                 wait_event_cmd(conf->wait_for_stripe,
2604                                     !list_empty(conf->inactive_list + hash),
2605                                     unlock_device_hash_lock(conf, hash),
2606                                     lock_device_hash_lock(conf, hash));
2607                 osh = get_free_stripe(conf, hash);
2608                 unlock_device_hash_lock(conf, hash);
2609
2610 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2611         for (i = 0; i < osh->nr_pages; i++) {
2612                 nsh->pages[i] = osh->pages[i];
2613                 osh->pages[i] = NULL;
2614         }
2615 #endif
2616                 for(i=0; i<conf->pool_size; i++) {
2617                         nsh->dev[i].page = osh->dev[i].page;
2618                         nsh->dev[i].orig_page = osh->dev[i].page;
2619                         nsh->dev[i].offset = osh->dev[i].offset;
2620                 }
2621                 nsh->hash_lock_index = hash;
2622                 free_stripe(conf->slab_cache, osh);
2623                 cnt++;
2624                 if (cnt >= conf->max_nr_stripes / NR_STRIPE_HASH_LOCKS +
2625                     !!((conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS) > hash)) {
2626                         hash++;
2627                         cnt = 0;
2628                 }
2629         }
2630         kmem_cache_destroy(conf->slab_cache);
2631
2632         /* Step 3.
2633          * At this point, we are holding all the stripes so the array
2634          * is completely stalled, so now is a good time to resize
2635          * conf->disks and the scribble region
2636          */
2637         ndisks = kcalloc(newsize, sizeof(struct disk_info), GFP_NOIO);
2638         if (ndisks) {
2639                 for (i = 0; i < conf->pool_size; i++)
2640                         ndisks[i] = conf->disks[i];
2641
2642                 for (i = conf->pool_size; i < newsize; i++) {
2643                         ndisks[i].extra_page = alloc_page(GFP_NOIO);
2644                         if (!ndisks[i].extra_page)
2645                                 err = -ENOMEM;
2646                 }
2647
2648                 if (err) {
2649                         for (i = conf->pool_size; i < newsize; i++)
2650                                 if (ndisks[i].extra_page)
2651                                         put_page(ndisks[i].extra_page);
2652                         kfree(ndisks);
2653                 } else {
2654                         kfree(conf->disks);
2655                         conf->disks = ndisks;
2656                 }
2657         } else
2658                 err = -ENOMEM;
2659
2660         conf->slab_cache = sc;
2661         conf->active_name = 1-conf->active_name;
2662
2663         /* Step 4, return new stripes to service */
2664         while(!list_empty(&newstripes)) {
2665                 nsh = list_entry(newstripes.next, struct stripe_head, lru);
2666                 list_del_init(&nsh->lru);
2667
2668 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2669                 for (i = 0; i < nsh->nr_pages; i++) {
2670                         if (nsh->pages[i])
2671                                 continue;
2672                         nsh->pages[i] = alloc_page(GFP_NOIO);
2673                         if (!nsh->pages[i])
2674                                 err = -ENOMEM;
2675                 }
2676
2677                 for (i = conf->raid_disks; i < newsize; i++) {
2678                         if (nsh->dev[i].page)
2679                                 continue;
2680                         nsh->dev[i].page = raid5_get_dev_page(nsh, i);
2681                         nsh->dev[i].orig_page = nsh->dev[i].page;
2682                         nsh->dev[i].offset = raid5_get_page_offset(nsh, i);
2683                 }
2684 #else
2685                 for (i=conf->raid_disks; i < newsize; i++)
2686                         if (nsh->dev[i].page == NULL) {
2687                                 struct page *p = alloc_page(GFP_NOIO);
2688                                 nsh->dev[i].page = p;
2689                                 nsh->dev[i].orig_page = p;
2690                                 nsh->dev[i].offset = 0;
2691                                 if (!p)
2692                                         err = -ENOMEM;
2693                         }
2694 #endif
2695                 raid5_release_stripe(nsh);
2696         }
2697         /* critical section pass, GFP_NOIO no longer needed */
2698
2699         if (!err)
2700                 conf->pool_size = newsize;
2701         mutex_unlock(&conf->cache_size_mutex);
2702
2703         return err;
2704 }
2705
2706 static int drop_one_stripe(struct r5conf *conf)
2707 {
2708         struct stripe_head *sh;
2709         int hash = (conf->max_nr_stripes - 1) & STRIPE_HASH_LOCKS_MASK;
2710
2711         spin_lock_irq(conf->hash_locks + hash);
2712         sh = get_free_stripe(conf, hash);
2713         spin_unlock_irq(conf->hash_locks + hash);
2714         if (!sh)
2715                 return 0;
2716         BUG_ON(atomic_read(&sh->count));
2717         shrink_buffers(sh);
2718         free_stripe(conf->slab_cache, sh);
2719         atomic_dec(&conf->active_stripes);
2720         conf->max_nr_stripes--;
2721         return 1;
2722 }
2723
2724 static void shrink_stripes(struct r5conf *conf)
2725 {
2726         while (conf->max_nr_stripes &&
2727                drop_one_stripe(conf))
2728                 ;
2729
2730         kmem_cache_destroy(conf->slab_cache);
2731         conf->slab_cache = NULL;
2732 }
2733
2734 /*
2735  * This helper wraps rcu_dereference_protected() and can be used when
2736  * it is known that the nr_pending of the rdev is elevated.
2737  */
2738 static struct md_rdev *rdev_pend_deref(struct md_rdev __rcu *rdev)
2739 {
2740         return rcu_dereference_protected(rdev,
2741                         atomic_read(&rcu_access_pointer(rdev)->nr_pending));
2742 }
2743
2744 /*
2745  * This helper wraps rcu_dereference_protected() and should be used
2746  * when it is known that the mddev_lock() is held. This is safe
2747  * seeing raid5_remove_disk() has the same lock held.
2748  */
2749 static struct md_rdev *rdev_mdlock_deref(struct mddev *mddev,
2750                                          struct md_rdev __rcu *rdev)
2751 {
2752         return rcu_dereference_protected(rdev,
2753                         lockdep_is_held(&mddev->reconfig_mutex));
2754 }
2755
2756 static void raid5_end_read_request(struct bio * bi)
2757 {
2758         struct stripe_head *sh = bi->bi_private;
2759         struct r5conf *conf = sh->raid_conf;
2760         int disks = sh->disks, i;
2761         struct md_rdev *rdev = NULL;
2762         sector_t s;
2763
2764         for (i=0 ; i<disks; i++)
2765                 if (bi == &sh->dev[i].req)
2766                         break;
2767
2768         pr_debug("end_read_request %llu/%d, count: %d, error %d.\n",
2769                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2770                 bi->bi_status);
2771         if (i == disks) {
2772                 BUG();
2773                 return;
2774         }
2775         if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2776                 /* If replacement finished while this request was outstanding,
2777                  * 'replacement' might be NULL already.
2778                  * In that case it moved down to 'rdev'.
2779                  * rdev is not removed until all requests are finished.
2780                  */
2781                 rdev = rdev_pend_deref(conf->disks[i].replacement);
2782         if (!rdev)
2783                 rdev = rdev_pend_deref(conf->disks[i].rdev);
2784
2785         if (use_new_offset(conf, sh))
2786                 s = sh->sector + rdev->new_data_offset;
2787         else
2788                 s = sh->sector + rdev->data_offset;
2789         if (!bi->bi_status) {
2790                 set_bit(R5_UPTODATE, &sh->dev[i].flags);
2791                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2792                         /* Note that this cannot happen on a
2793                          * replacement device.  We just fail those on
2794                          * any error
2795                          */
2796                         pr_info_ratelimited(
2797                                 "md/raid:%s: read error corrected (%lu sectors at %llu on %pg)\n",
2798                                 mdname(conf->mddev), RAID5_STRIPE_SECTORS(conf),
2799                                 (unsigned long long)s,
2800                                 rdev->bdev);
2801                         atomic_add(RAID5_STRIPE_SECTORS(conf), &rdev->corrected_errors);
2802                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2803                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2804                 } else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2805                         clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2806
2807                 if (test_bit(R5_InJournal, &sh->dev[i].flags))
2808                         /*
2809                          * end read for a page in journal, this
2810                          * must be preparing for prexor in rmw
2811                          */
2812                         set_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags);
2813
2814                 if (atomic_read(&rdev->read_errors))
2815                         atomic_set(&rdev->read_errors, 0);
2816         } else {
2817                 int retry = 0;
2818                 int set_bad = 0;
2819
2820                 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
2821                 if (!(bi->bi_status == BLK_STS_PROTECTION))
2822                         atomic_inc(&rdev->read_errors);
2823                 if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2824                         pr_warn_ratelimited(
2825                                 "md/raid:%s: read error on replacement device (sector %llu on %pg).\n",
2826                                 mdname(conf->mddev),
2827                                 (unsigned long long)s,
2828                                 rdev->bdev);
2829                 else if (conf->mddev->degraded >= conf->max_degraded) {
2830                         set_bad = 1;
2831                         pr_warn_ratelimited(
2832                                 "md/raid:%s: read error not correctable (sector %llu on %pg).\n",
2833                                 mdname(conf->mddev),
2834                                 (unsigned long long)s,
2835                                 rdev->bdev);
2836                 } else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
2837                         /* Oh, no!!! */
2838                         set_bad = 1;
2839                         pr_warn_ratelimited(
2840                                 "md/raid:%s: read error NOT corrected!! (sector %llu on %pg).\n",
2841                                 mdname(conf->mddev),
2842                                 (unsigned long long)s,
2843                                 rdev->bdev);
2844                 } else if (atomic_read(&rdev->read_errors)
2845                          > conf->max_nr_stripes) {
2846                         if (!test_bit(Faulty, &rdev->flags)) {
2847                                 pr_warn("md/raid:%s: %d read_errors > %d stripes\n",
2848                                     mdname(conf->mddev),
2849                                     atomic_read(&rdev->read_errors),
2850                                     conf->max_nr_stripes);
2851                                 pr_warn("md/raid:%s: Too many read errors, failing device %pg.\n",
2852                                     mdname(conf->mddev), rdev->bdev);
2853                         }
2854                 } else
2855                         retry = 1;
2856                 if (set_bad && test_bit(In_sync, &rdev->flags)
2857                     && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2858                         retry = 1;
2859                 if (retry)
2860                         if (sh->qd_idx >= 0 && sh->pd_idx == i)
2861                                 set_bit(R5_ReadError, &sh->dev[i].flags);
2862                         else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
2863                                 set_bit(R5_ReadError, &sh->dev[i].flags);
2864                                 clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2865                         } else
2866                                 set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2867                 else {
2868                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2869                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2870                         if (!(set_bad
2871                               && test_bit(In_sync, &rdev->flags)
2872                               && rdev_set_badblocks(
2873                                       rdev, sh->sector, RAID5_STRIPE_SECTORS(conf), 0)))
2874                                 md_error(conf->mddev, rdev);
2875                 }
2876         }
2877         rdev_dec_pending(rdev, conf->mddev);
2878         bio_uninit(bi);
2879         clear_bit(R5_LOCKED, &sh->dev[i].flags);
2880         set_bit(STRIPE_HANDLE, &sh->state);
2881         raid5_release_stripe(sh);
2882 }
2883
2884 static void raid5_end_write_request(struct bio *bi)
2885 {
2886         struct stripe_head *sh = bi->bi_private;
2887         struct r5conf *conf = sh->raid_conf;
2888         int disks = sh->disks, i;
2889         struct md_rdev *rdev;
2890         sector_t first_bad;
2891         int bad_sectors;
2892         int replacement = 0;
2893
2894         for (i = 0 ; i < disks; i++) {
2895                 if (bi == &sh->dev[i].req) {
2896                         rdev = rdev_pend_deref(conf->disks[i].rdev);
2897                         break;
2898                 }
2899                 if (bi == &sh->dev[i].rreq) {
2900                         rdev = rdev_pend_deref(conf->disks[i].replacement);
2901                         if (rdev)
2902                                 replacement = 1;
2903                         else
2904                                 /* rdev was removed and 'replacement'
2905                                  * replaced it.  rdev is not removed
2906                                  * until all requests are finished.
2907                                  */
2908                                 rdev = rdev_pend_deref(conf->disks[i].rdev);
2909                         break;
2910                 }
2911         }
2912         pr_debug("end_write_request %llu/%d, count %d, error: %d.\n",
2913                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2914                 bi->bi_status);
2915         if (i == disks) {
2916                 BUG();
2917                 return;
2918         }
2919
2920         if (replacement) {
2921                 if (bi->bi_status)
2922                         md_error(conf->mddev, rdev);
2923                 else if (is_badblock(rdev, sh->sector,
2924                                      RAID5_STRIPE_SECTORS(conf),
2925                                      &first_bad, &bad_sectors))
2926                         set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
2927         } else {
2928                 if (bi->bi_status) {
2929                         set_bit(STRIPE_DEGRADED, &sh->state);
2930                         set_bit(WriteErrorSeen, &rdev->flags);
2931                         set_bit(R5_WriteError, &sh->dev[i].flags);
2932                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
2933                                 set_bit(MD_RECOVERY_NEEDED,
2934                                         &rdev->mddev->recovery);
2935                 } else if (is_badblock(rdev, sh->sector,
2936                                        RAID5_STRIPE_SECTORS(conf),
2937                                        &first_bad, &bad_sectors)) {
2938                         set_bit(R5_MadeGood, &sh->dev[i].flags);
2939                         if (test_bit(R5_ReadError, &sh->dev[i].flags))
2940                                 /* That was a successful write so make
2941                                  * sure it looks like we already did
2942                                  * a re-write.
2943                                  */
2944                                 set_bit(R5_ReWrite, &sh->dev[i].flags);
2945                 }
2946         }
2947         rdev_dec_pending(rdev, conf->mddev);
2948
2949         if (sh->batch_head && bi->bi_status && !replacement)
2950                 set_bit(STRIPE_BATCH_ERR, &sh->batch_head->state);
2951
2952         bio_uninit(bi);
2953         if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
2954                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
2955         set_bit(STRIPE_HANDLE, &sh->state);
2956
2957         if (sh->batch_head && sh != sh->batch_head)
2958                 raid5_release_stripe(sh->batch_head);
2959         raid5_release_stripe(sh);
2960 }
2961
2962 static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
2963 {
2964         struct r5conf *conf = mddev->private;
2965         unsigned long flags;
2966         pr_debug("raid456: error called\n");
2967
2968         pr_crit("md/raid:%s: Disk failure on %pg, disabling device.\n",
2969                 mdname(mddev), rdev->bdev);
2970
2971         spin_lock_irqsave(&conf->device_lock, flags);
2972         set_bit(Faulty, &rdev->flags);
2973         clear_bit(In_sync, &rdev->flags);
2974         mddev->degraded = raid5_calc_degraded(conf);
2975
2976         if (has_failed(conf)) {
2977                 set_bit(MD_BROKEN, &conf->mddev->flags);
2978                 conf->recovery_disabled = mddev->recovery_disabled;
2979
2980                 pr_crit("md/raid:%s: Cannot continue operation (%d/%d failed).\n",
2981                         mdname(mddev), mddev->degraded, conf->raid_disks);
2982         } else {
2983                 pr_crit("md/raid:%s: Operation continuing on %d devices.\n",
2984                         mdname(mddev), conf->raid_disks - mddev->degraded);
2985         }
2986
2987         spin_unlock_irqrestore(&conf->device_lock, flags);
2988         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2989
2990         set_bit(Blocked, &rdev->flags);
2991         set_mask_bits(&mddev->sb_flags, 0,
2992                       BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
2993         r5c_update_on_rdev_error(mddev, rdev);
2994 }
2995
2996 /*
2997  * Input: a 'big' sector number,
2998  * Output: index of the data and parity disk, and the sector # in them.
2999  */
3000 sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
3001                               int previous, int *dd_idx,
3002                               struct stripe_head *sh)
3003 {
3004         sector_t stripe, stripe2;
3005         sector_t chunk_number;
3006         unsigned int chunk_offset;
3007         int pd_idx, qd_idx;
3008         int ddf_layout = 0;
3009         sector_t new_sector;
3010         int algorithm = previous ? conf->prev_algo
3011                                  : conf->algorithm;
3012         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
3013                                          : conf->chunk_sectors;
3014         int raid_disks = previous ? conf->previous_raid_disks
3015                                   : conf->raid_disks;
3016         int data_disks = raid_disks - conf->max_degraded;
3017
3018         /* First compute the information on this sector */
3019
3020         /*
3021          * Compute the chunk number and the sector offset inside the chunk
3022          */
3023         chunk_offset = sector_div(r_sector, sectors_per_chunk);
3024         chunk_number = r_sector;
3025
3026         /*
3027          * Compute the stripe number
3028          */
3029         stripe = chunk_number;
3030         *dd_idx = sector_div(stripe, data_disks);
3031         stripe2 = stripe;
3032         /*
3033          * Select the parity disk based on the user selected algorithm.
3034          */
3035         pd_idx = qd_idx = -1;
3036         switch(conf->level) {
3037         case 4:
3038                 pd_idx = data_disks;
3039                 break;
3040         case 5:
3041                 switch (algorithm) {
3042                 case ALGORITHM_LEFT_ASYMMETRIC:
3043                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
3044                         if (*dd_idx >= pd_idx)
3045                                 (*dd_idx)++;
3046                         break;
3047                 case ALGORITHM_RIGHT_ASYMMETRIC:
3048                         pd_idx = sector_div(stripe2, raid_disks);
3049                         if (*dd_idx >= pd_idx)
3050                                 (*dd_idx)++;
3051                         break;
3052                 case ALGORITHM_LEFT_SYMMETRIC:
3053                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
3054                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
3055                         break;
3056                 case ALGORITHM_RIGHT_SYMMETRIC:
3057                         pd_idx = sector_div(stripe2, raid_disks);
3058                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
3059                         break;
3060                 case ALGORITHM_PARITY_0:
3061                         pd_idx = 0;
3062                         (*dd_idx)++;
3063                         break;
3064                 case ALGORITHM_PARITY_N:
3065                         pd_idx = data_disks;
3066                         break;
3067                 default:
3068                         BUG();
3069                 }
3070                 break;
3071         case 6:
3072
3073                 switch (algorithm) {
3074                 case ALGORITHM_LEFT_ASYMMETRIC:
3075                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3076                         qd_idx = pd_idx + 1;
3077                         if (pd_idx == raid_disks-1) {
3078                                 (*dd_idx)++;    /* Q D D D P */
3079                                 qd_idx = 0;
3080                         } else if (*dd_idx >= pd_idx)
3081                                 (*dd_idx) += 2; /* D D P Q D */
3082                         break;
3083                 case ALGORITHM_RIGHT_ASYMMETRIC:
3084                         pd_idx = sector_div(stripe2, raid_disks);
3085                         qd_idx = pd_idx + 1;
3086                         if (pd_idx == raid_disks-1) {
3087                                 (*dd_idx)++;    /* Q D D D P */
3088                                 qd_idx = 0;
3089                         } else if (*dd_idx >= pd_idx)
3090                                 (*dd_idx) += 2; /* D D P Q D */
3091                         break;
3092                 case ALGORITHM_LEFT_SYMMETRIC:
3093                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3094                         qd_idx = (pd_idx + 1) % raid_disks;
3095                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
3096                         break;
3097                 case ALGORITHM_RIGHT_SYMMETRIC:
3098                         pd_idx = sector_div(stripe2, raid_disks);
3099                         qd_idx = (pd_idx + 1) % raid_disks;
3100                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
3101                         break;
3102
3103                 case ALGORITHM_PARITY_0:
3104                         pd_idx = 0;
3105                         qd_idx = 1;
3106                         (*dd_idx) += 2;
3107                         break;
3108                 case ALGORITHM_PARITY_N:
3109                         pd_idx = data_disks;
3110                         qd_idx = data_disks + 1;
3111                         break;
3112
3113                 case ALGORITHM_ROTATING_ZERO_RESTART:
3114                         /* Exactly the same as RIGHT_ASYMMETRIC, but or
3115                          * of blocks for computing Q is different.
3116                          */
3117                         pd_idx = sector_div(stripe2, raid_disks);
3118                         qd_idx = pd_idx + 1;
3119                         if (pd_idx == raid_disks-1) {
3120                                 (*dd_idx)++;    /* Q D D D P */
3121                                 qd_idx = 0;
3122                         } else if (*dd_idx >= pd_idx)
3123                                 (*dd_idx) += 2; /* D D P Q D */
3124                         ddf_layout = 1;
3125                         break;
3126
3127                 case ALGORITHM_ROTATING_N_RESTART:
3128                         /* Same a left_asymmetric, by first stripe is
3129                          * D D D P Q  rather than
3130                          * Q D D D P
3131                          */
3132                         stripe2 += 1;
3133                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3134                         qd_idx = pd_idx + 1;
3135                         if (pd_idx == raid_disks-1) {
3136                                 (*dd_idx)++;    /* Q D D D P */
3137                                 qd_idx = 0;
3138                         } else if (*dd_idx >= pd_idx)
3139                                 (*dd_idx) += 2; /* D D P Q D */
3140                         ddf_layout = 1;
3141                         break;
3142
3143                 case ALGORITHM_ROTATING_N_CONTINUE:
3144                         /* Same as left_symmetric but Q is before P */
3145                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3146                         qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
3147                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
3148                         ddf_layout = 1;
3149                         break;
3150
3151                 case ALGORITHM_LEFT_ASYMMETRIC_6:
3152                         /* RAID5 left_asymmetric, with Q on last device */
3153                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
3154                         if (*dd_idx >= pd_idx)
3155                                 (*dd_idx)++;
3156                         qd_idx = raid_disks - 1;
3157                         break;
3158
3159                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
3160                         pd_idx = sector_div(stripe2, raid_disks-1);
3161                         if (*dd_idx >= pd_idx)
3162                                 (*dd_idx)++;
3163                         qd_idx = raid_disks - 1;
3164                         break;
3165
3166                 case ALGORITHM_LEFT_SYMMETRIC_6:
3167                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
3168                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
3169                         qd_idx = raid_disks - 1;
3170                         break;
3171
3172                 case ALGORITHM_RIGHT_SYMMETRIC_6:
3173                         pd_idx = sector_div(stripe2, raid_disks-1);
3174                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
3175                         qd_idx = raid_disks - 1;
3176                         break;
3177
3178                 case ALGORITHM_PARITY_0_6:
3179                         pd_idx = 0;
3180                         (*dd_idx)++;
3181                         qd_idx = raid_disks - 1;
3182                         break;
3183
3184                 default:
3185                         BUG();
3186                 }
3187                 break;
3188         }
3189
3190         if (sh) {
3191                 sh->pd_idx = pd_idx;
3192                 sh->qd_idx = qd_idx;
3193                 sh->ddf_layout = ddf_layout;
3194         }
3195         /*
3196          * Finally, compute the new sector number
3197          */
3198         new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
3199         return new_sector;
3200 }
3201
3202 sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous)
3203 {
3204         struct r5conf *conf = sh->raid_conf;
3205         int raid_disks = sh->disks;
3206         int data_disks = raid_disks - conf->max_degraded;
3207         sector_t new_sector = sh->sector, check;
3208         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
3209                                          : conf->chunk_sectors;
3210         int algorithm = previous ? conf->prev_algo
3211                                  : conf->algorithm;
3212         sector_t stripe;
3213         int chunk_offset;
3214         sector_t chunk_number;
3215         int dummy1, dd_idx = i;
3216         sector_t r_sector;
3217         struct stripe_head sh2;
3218
3219         chunk_offset = sector_div(new_sector, sectors_per_chunk);
3220         stripe = new_sector;
3221
3222         if (i == sh->pd_idx)
3223                 return 0;
3224         switch(conf->level) {
3225         case 4: break;
3226         case 5:
3227                 switch (algorithm) {
3228                 case ALGORITHM_LEFT_ASYMMETRIC:
3229                 case ALGORITHM_RIGHT_ASYMMETRIC:
3230                         if (i > sh->pd_idx)
3231                                 i--;
3232                         break;
3233                 case ALGORITHM_LEFT_SYMMETRIC:
3234                 case ALGORITHM_RIGHT_SYMMETRIC:
3235                         if (i < sh->pd_idx)
3236                                 i += raid_disks;
3237                         i -= (sh->pd_idx + 1);
3238                         break;
3239                 case ALGORITHM_PARITY_0:
3240                         i -= 1;
3241                         break;
3242                 case ALGORITHM_PARITY_N:
3243                         break;
3244                 default:
3245                         BUG();
3246                 }
3247                 break;
3248         case 6:
3249                 if (i == sh->qd_idx)
3250                         return 0; /* It is the Q disk */
3251                 switch (algorithm) {
3252                 case ALGORITHM_LEFT_ASYMMETRIC:
3253                 case ALGORITHM_RIGHT_ASYMMETRIC:
3254                 case ALGORITHM_ROTATING_ZERO_RESTART:
3255                 case ALGORITHM_ROTATING_N_RESTART:
3256                         if (sh->pd_idx == raid_disks-1)
3257                                 i--;    /* Q D D D P */
3258                         else if (i > sh->pd_idx)
3259                                 i -= 2; /* D D P Q D */
3260                         break;
3261                 case ALGORITHM_LEFT_SYMMETRIC:
3262                 case ALGORITHM_RIGHT_SYMMETRIC:
3263                         if (sh->pd_idx == raid_disks-1)
3264                                 i--; /* Q D D D P */
3265                         else {
3266                                 /* D D P Q D */
3267                                 if (i < sh->pd_idx)
3268                                         i += raid_disks;
3269                                 i -= (sh->pd_idx + 2);
3270                         }
3271                         break;
3272                 case ALGORITHM_PARITY_0:
3273                         i -= 2;
3274                         break;
3275                 case ALGORITHM_PARITY_N:
3276                         break;
3277                 case ALGORITHM_ROTATING_N_CONTINUE:
3278                         /* Like left_symmetric, but P is before Q */
3279                         if (sh->pd_idx == 0)
3280                                 i--;    /* P D D D Q */
3281                         else {
3282                                 /* D D Q P D */
3283                                 if (i < sh->pd_idx)
3284                                         i += raid_disks;
3285                                 i -= (sh->pd_idx + 1);
3286                         }
3287                         break;
3288                 case ALGORITHM_LEFT_ASYMMETRIC_6:
3289                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
3290                         if (i > sh->pd_idx)
3291                                 i--;
3292                         break;
3293                 case ALGORITHM_LEFT_SYMMETRIC_6:
3294                 case ALGORITHM_RIGHT_SYMMETRIC_6:
3295                         if (i < sh->pd_idx)
3296                                 i += data_disks + 1;
3297                         i -= (sh->pd_idx + 1);
3298                         break;
3299                 case ALGORITHM_PARITY_0_6:
3300                         i -= 1;
3301                         break;
3302                 default:
3303                         BUG();
3304                 }
3305                 break;
3306         }
3307
3308         chunk_number = stripe * data_disks + i;
3309         r_sector = chunk_number * sectors_per_chunk + chunk_offset;
3310
3311         check = raid5_compute_sector(conf, r_sector,
3312                                      previous, &dummy1, &sh2);
3313         if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
3314                 || sh2.qd_idx != sh->qd_idx) {
3315                 pr_warn("md/raid:%s: compute_blocknr: map not correct\n",
3316                         mdname(conf->mddev));
3317                 return 0;
3318         }
3319         return r_sector;
3320 }
3321
3322 /*
3323  * There are cases where we want handle_stripe_dirtying() and
3324  * schedule_reconstruction() to delay towrite to some dev of a stripe.
3325  *
3326  * This function checks whether we want to delay the towrite. Specifically,
3327  * we delay the towrite when:
3328  *
3329  *   1. degraded stripe has a non-overwrite to the missing dev, AND this
3330  *      stripe has data in journal (for other devices).
3331  *
3332  *      In this case, when reading data for the non-overwrite dev, it is
3333  *      necessary to handle complex rmw of write back cache (prexor with
3334  *      orig_page, and xor with page). To keep read path simple, we would
3335  *      like to flush data in journal to RAID disks first, so complex rmw
3336  *      is handled in the write patch (handle_stripe_dirtying).
3337  *
3338  *   2. when journal space is critical (R5C_LOG_CRITICAL=1)
3339  *
3340  *      It is important to be able to flush all stripes in raid5-cache.
3341  *      Therefore, we need reserve some space on the journal device for
3342  *      these flushes. If flush operation includes pending writes to the
3343  *      stripe, we need to reserve (conf->raid_disk + 1) pages per stripe
3344  *      for the flush out. If we exclude these pending writes from flush
3345  *      operation, we only need (conf->max_degraded + 1) pages per stripe.
3346  *      Therefore, excluding pending writes in these cases enables more
3347  *      efficient use of the journal device.
3348  *
3349  *      Note: To make sure the stripe makes progress, we only delay
3350  *      towrite for stripes with data already in journal (injournal > 0).
3351  *      When LOG_CRITICAL, stripes with injournal == 0 will be sent to
3352  *      no_space_stripes list.
3353  *
3354  *   3. during journal failure
3355  *      In journal failure, we try to flush all cached data to raid disks
3356  *      based on data in stripe cache. The array is read-only to upper
3357  *      layers, so we would skip all pending writes.
3358  *
3359  */
3360 static inline bool delay_towrite(struct r5conf *conf,
3361                                  struct r5dev *dev,
3362                                  struct stripe_head_state *s)
3363 {
3364         /* case 1 above */
3365         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3366             !test_bit(R5_Insync, &dev->flags) && s->injournal)
3367                 return true;
3368         /* case 2 above */
3369         if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
3370             s->injournal > 0)
3371                 return true;
3372         /* case 3 above */
3373         if (s->log_failed && s->injournal)
3374                 return true;
3375         return false;
3376 }
3377
3378 static void
3379 schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
3380                          int rcw, int expand)
3381 {
3382         int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx, disks = sh->disks;
3383         struct r5conf *conf = sh->raid_conf;
3384         int level = conf->level;
3385
3386         if (rcw) {
3387                 /*
3388                  * In some cases, handle_stripe_dirtying initially decided to
3389                  * run rmw and allocates extra page for prexor. However, rcw is
3390                  * cheaper later on. We need to free the extra page now,
3391                  * because we won't be able to do that in ops_complete_prexor().
3392                  */
3393                 r5c_release_extra_page(sh);
3394
3395                 for (i = disks; i--; ) {
3396                         struct r5dev *dev = &sh->dev[i];
3397
3398                         if (dev->towrite && !delay_towrite(conf, dev, s)) {
3399                                 set_bit(R5_LOCKED, &dev->flags);
3400                                 set_bit(R5_Wantdrain, &dev->flags);
3401                                 if (!expand)
3402                                         clear_bit(R5_UPTODATE, &dev->flags);
3403                                 s->locked++;
3404                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3405                                 set_bit(R5_LOCKED, &dev->flags);
3406                                 s->locked++;
3407                         }
3408                 }
3409                 /* if we are not expanding this is a proper write request, and
3410                  * there will be bios with new data to be drained into the
3411                  * stripe cache
3412                  */
3413                 if (!expand) {
3414                         if (!s->locked)
3415                                 /* False alarm, nothing to do */
3416                                 return;
3417                         sh->reconstruct_state = reconstruct_state_drain_run;
3418                         set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3419                 } else
3420                         sh->reconstruct_state = reconstruct_state_run;
3421
3422                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3423
3424                 if (s->locked + conf->max_degraded == disks)
3425                         if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
3426                                 atomic_inc(&conf->pending_full_writes);
3427         } else {
3428                 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
3429                         test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
3430                 BUG_ON(level == 6 &&
3431                         (!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
3432                            test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));
3433
3434                 for (i = disks; i--; ) {
3435                         struct r5dev *dev = &sh->dev[i];
3436                         if (i == pd_idx || i == qd_idx)
3437                                 continue;
3438
3439                         if (dev->towrite &&
3440                             (test_bit(R5_UPTODATE, &dev->flags) ||
3441                              test_bit(R5_Wantcompute, &dev->flags))) {
3442                                 set_bit(R5_Wantdrain, &dev->flags);
3443                                 set_bit(R5_LOCKED, &dev->flags);
3444                                 clear_bit(R5_UPTODATE, &dev->flags);
3445                                 s->locked++;
3446                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3447                                 set_bit(R5_LOCKED, &dev->flags);
3448                                 s->locked++;
3449                         }
3450                 }
3451                 if (!s->locked)
3452                         /* False alarm - nothing to do */
3453                         return;
3454                 sh->reconstruct_state = reconstruct_state_prexor_drain_run;
3455                 set_bit(STRIPE_OP_PREXOR, &s->ops_request);
3456                 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3457                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3458         }
3459
3460         /* keep the parity disk(s) locked while asynchronous operations
3461          * are in flight
3462          */
3463         set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
3464         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
3465         s->locked++;
3466
3467         if (level == 6) {
3468                 int qd_idx = sh->qd_idx;
3469                 struct r5dev *dev = &sh->dev[qd_idx];
3470
3471                 set_bit(R5_LOCKED, &dev->flags);
3472                 clear_bit(R5_UPTODATE, &dev->flags);
3473                 s->locked++;
3474         }
3475
3476         if (raid5_has_ppl(sh->raid_conf) && sh->ppl_page &&
3477             test_bit(STRIPE_OP_BIODRAIN, &s->ops_request) &&
3478             !test_bit(STRIPE_FULL_WRITE, &sh->state) &&
3479             test_bit(R5_Insync, &sh->dev[pd_idx].flags))
3480                 set_bit(STRIPE_OP_PARTIAL_PARITY, &s->ops_request);
3481
3482         pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
3483                 __func__, (unsigned long long)sh->sector,
3484                 s->locked, s->ops_request);
3485 }
3486
3487 static bool stripe_bio_overlaps(struct stripe_head *sh, struct bio *bi,
3488                                 int dd_idx, int forwrite)
3489 {
3490         struct r5conf *conf = sh->raid_conf;
3491         struct bio **bip;
3492
3493         pr_debug("checking bi b#%llu to stripe s#%llu\n",
3494                  bi->bi_iter.bi_sector, sh->sector);
3495
3496         /* Don't allow new IO added to stripes in batch list */
3497         if (sh->batch_head)
3498                 return true;
3499
3500         if (forwrite)
3501                 bip = &sh->dev[dd_idx].towrite;
3502         else
3503                 bip = &sh->dev[dd_idx].toread;
3504
3505         while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector) {
3506                 if (bio_end_sector(*bip) > bi->bi_iter.bi_sector)
3507                         return true;
3508                 bip = &(*bip)->bi_next;
3509         }
3510
3511         if (*bip && (*bip)->bi_iter.bi_sector < bio_end_sector(bi))
3512                 return true;
3513
3514         if (forwrite && raid5_has_ppl(conf)) {
3515                 /*
3516                  * With PPL only writes to consecutive data chunks within a
3517                  * stripe are allowed because for a single stripe_head we can
3518                  * only have one PPL entry at a time, which describes one data
3519                  * range. Not really an overlap, but wait_for_overlap can be
3520                  * used to handle this.
3521                  */
3522                 sector_t sector;
3523                 sector_t first = 0;
3524                 sector_t last = 0;
3525                 int count = 0;
3526                 int i;
3527
3528                 for (i = 0; i < sh->disks; i++) {
3529                         if (i != sh->pd_idx &&
3530                             (i == dd_idx || sh->dev[i].towrite)) {
3531                                 sector = sh->dev[i].sector;
3532                                 if (count == 0 || sector < first)
3533                                         first = sector;
3534                                 if (sector > last)
3535                                         last = sector;
3536                                 count++;
3537                         }
3538                 }
3539
3540                 if (first + conf->chunk_sectors * (count - 1) != last)
3541                         return true;
3542         }
3543
3544         return false;
3545 }
3546
3547 static void __add_stripe_bio(struct stripe_head *sh, struct bio *bi,
3548                              int dd_idx, int forwrite, int previous)
3549 {
3550         struct r5conf *conf = sh->raid_conf;
3551         struct bio **bip;
3552         int firstwrite = 0;
3553
3554         if (forwrite) {
3555                 bip = &sh->dev[dd_idx].towrite;
3556                 if (!*bip)
3557                         firstwrite = 1;
3558         } else {
3559                 bip = &sh->dev[dd_idx].toread;
3560         }
3561
3562         while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector)
3563                 bip = &(*bip)->bi_next;
3564
3565         if (!forwrite || previous)
3566                 clear_bit(STRIPE_BATCH_READY, &sh->state);
3567
3568         BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
3569         if (*bip)
3570                 bi->bi_next = *bip;
3571         *bip = bi;
3572         bio_inc_remaining(bi);
3573         md_write_inc(conf->mddev, bi);
3574
3575         if (forwrite) {
3576                 /* check if page is covered */
3577                 sector_t sector = sh->dev[dd_idx].sector;
3578                 for (bi=sh->dev[dd_idx].towrite;
3579                      sector < sh->dev[dd_idx].sector + RAID5_STRIPE_SECTORS(conf) &&
3580                              bi && bi->bi_iter.bi_sector <= sector;
3581                      bi = r5_next_bio(conf, bi, sh->dev[dd_idx].sector)) {
3582                         if (bio_end_sector(bi) >= sector)
3583                                 sector = bio_end_sector(bi);
3584                 }
3585                 if (sector >= sh->dev[dd_idx].sector + RAID5_STRIPE_SECTORS(conf))
3586                         if (!test_and_set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags))
3587                                 sh->overwrite_disks++;
3588         }
3589
3590         pr_debug("added bi b#%llu to stripe s#%llu, disk %d, logical %llu\n",
3591                  (*bip)->bi_iter.bi_sector, sh->sector, dd_idx,
3592                  sh->dev[dd_idx].sector);
3593
3594         if (conf->mddev->bitmap && firstwrite) {
3595                 /* Cannot hold spinlock over bitmap_startwrite,
3596                  * but must ensure this isn't added to a batch until
3597                  * we have added to the bitmap and set bm_seq.
3598                  * So set STRIPE_BITMAP_PENDING to prevent
3599                  * batching.
3600                  * If multiple __add_stripe_bio() calls race here they
3601                  * much all set STRIPE_BITMAP_PENDING.  So only the first one
3602                  * to complete "bitmap_startwrite" gets to set
3603                  * STRIPE_BIT_DELAY.  This is important as once a stripe
3604                  * is added to a batch, STRIPE_BIT_DELAY cannot be changed
3605                  * any more.
3606                  */
3607                 set_bit(STRIPE_BITMAP_PENDING, &sh->state);
3608                 spin_unlock_irq(&sh->stripe_lock);
3609                 md_bitmap_startwrite(conf->mddev->bitmap, sh->sector,
3610                                      RAID5_STRIPE_SECTORS(conf), 0);
3611                 spin_lock_irq(&sh->stripe_lock);
3612                 clear_bit(STRIPE_BITMAP_PENDING, &sh->state);
3613                 if (!sh->batch_head) {
3614                         sh->bm_seq = conf->seq_flush+1;
3615                         set_bit(STRIPE_BIT_DELAY, &sh->state);
3616                 }
3617         }
3618 }
3619
3620 /*
3621  * Each stripe/dev can have one or more bios attached.
3622  * toread/towrite point to the first in a chain.
3623  * The bi_next chain must be in order.
3624  */
3625 static bool add_stripe_bio(struct stripe_head *sh, struct bio *bi,
3626                            int dd_idx, int forwrite, int previous)
3627 {
3628         spin_lock_irq(&sh->stripe_lock);
3629
3630         if (stripe_bio_overlaps(sh, bi, dd_idx, forwrite)) {
3631                 set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
3632                 spin_unlock_irq(&sh->stripe_lock);
3633                 return false;
3634         }
3635
3636         __add_stripe_bio(sh, bi, dd_idx, forwrite, previous);
3637         spin_unlock_irq(&sh->stripe_lock);
3638         return true;
3639 }
3640
3641 static void end_reshape(struct r5conf *conf);
3642
3643 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
3644                             struct stripe_head *sh)
3645 {
3646         int sectors_per_chunk =
3647                 previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
3648         int dd_idx;
3649         int chunk_offset = sector_div(stripe, sectors_per_chunk);
3650         int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
3651
3652         raid5_compute_sector(conf,
3653                              stripe * (disks - conf->max_degraded)
3654                              *sectors_per_chunk + chunk_offset,
3655                              previous,
3656                              &dd_idx, sh);
3657 }
3658
3659 static void
3660 handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
3661                      struct stripe_head_state *s, int disks)
3662 {
3663         int i;
3664         BUG_ON(sh->batch_head);
3665         for (i = disks; i--; ) {
3666                 struct bio *bi;
3667                 int bitmap_end = 0;
3668
3669                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
3670                         struct md_rdev *rdev;
3671                         rcu_read_lock();
3672                         rdev = rcu_dereference(conf->disks[i].rdev);
3673                         if (rdev && test_bit(In_sync, &rdev->flags) &&
3674                             !test_bit(Faulty, &rdev->flags))
3675                                 atomic_inc(&rdev->nr_pending);
3676                         else
3677                                 rdev = NULL;
3678                         rcu_read_unlock();
3679                         if (rdev) {
3680                                 if (!rdev_set_badblocks(
3681                                             rdev,
3682                                             sh->sector,
3683                                             RAID5_STRIPE_SECTORS(conf), 0))
3684                                         md_error(conf->mddev, rdev);
3685                                 rdev_dec_pending(rdev, conf->mddev);
3686                         }
3687                 }
3688                 spin_lock_irq(&sh->stripe_lock);
3689                 /* fail all writes first */
3690                 bi = sh->dev[i].towrite;
3691                 sh->dev[i].towrite = NULL;
3692                 sh->overwrite_disks = 0;
3693                 spin_unlock_irq(&sh->stripe_lock);
3694                 if (bi)
3695                         bitmap_end = 1;
3696
3697                 log_stripe_write_finished(sh);
3698
3699                 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3700                         wake_up(&conf->wait_for_overlap);
3701
3702                 while (bi && bi->bi_iter.bi_sector <
3703                         sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3704                         struct bio *nextbi = r5_next_bio(conf, bi, sh->dev[i].sector);
3705
3706                         md_write_end(conf->mddev);
3707                         bio_io_error(bi);
3708                         bi = nextbi;
3709                 }
3710                 if (bitmap_end)
3711                         md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3712                                            RAID5_STRIPE_SECTORS(conf), 0, 0);
3713                 bitmap_end = 0;
3714                 /* and fail all 'written' */
3715                 bi = sh->dev[i].written;
3716                 sh->dev[i].written = NULL;
3717                 if (test_and_clear_bit(R5_SkipCopy, &sh->dev[i].flags)) {
3718                         WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
3719                         sh->dev[i].page = sh->dev[i].orig_page;
3720                 }
3721
3722                 if (bi) bitmap_end = 1;
3723                 while (bi && bi->bi_iter.bi_sector <
3724                        sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3725                         struct bio *bi2 = r5_next_bio(conf, bi, sh->dev[i].sector);
3726
3727                         md_write_end(conf->mddev);
3728                         bio_io_error(bi);
3729                         bi = bi2;
3730                 }
3731
3732                 /* fail any reads if this device is non-operational and
3733                  * the data has not reached the cache yet.
3734                  */
3735                 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
3736                     s->failed > conf->max_degraded &&
3737                     (!test_bit(R5_Insync, &sh->dev[i].flags) ||
3738                       test_bit(R5_ReadError, &sh->dev[i].flags))) {
3739                         spin_lock_irq(&sh->stripe_lock);
3740                         bi = sh->dev[i].toread;
3741                         sh->dev[i].toread = NULL;
3742                         spin_unlock_irq(&sh->stripe_lock);
3743                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3744                                 wake_up(&conf->wait_for_overlap);
3745                         if (bi)
3746                                 s->to_read--;
3747                         while (bi && bi->bi_iter.bi_sector <
3748                                sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3749                                 struct bio *nextbi =
3750                                         r5_next_bio(conf, bi, sh->dev[i].sector);
3751
3752                                 bio_io_error(bi);
3753                                 bi = nextbi;
3754                         }
3755                 }
3756                 if (bitmap_end)
3757                         md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3758                                            RAID5_STRIPE_SECTORS(conf), 0, 0);
3759                 /* If we were in the middle of a write the parity block might
3760                  * still be locked - so just clear all R5_LOCKED flags
3761                  */
3762                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
3763         }
3764         s->to_write = 0;
3765         s->written = 0;
3766
3767         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3768                 if (atomic_dec_and_test(&conf->pending_full_writes))
3769                         md_wakeup_thread(conf->mddev->thread);
3770 }
3771
3772 static void
3773 handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
3774                    struct stripe_head_state *s)
3775 {
3776         int abort = 0;
3777         int i;
3778
3779         BUG_ON(sh->batch_head);
3780         clear_bit(STRIPE_SYNCING, &sh->state);
3781         if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
3782                 wake_up(&conf->wait_for_overlap);
3783         s->syncing = 0;
3784         s->replacing = 0;
3785         /* There is nothing more to do for sync/check/repair.
3786          * Don't even need to abort as that is handled elsewhere
3787          * if needed, and not always wanted e.g. if there is a known
3788          * bad block here.
3789          * For recover/replace we need to record a bad block on all
3790          * non-sync devices, or abort the recovery
3791          */
3792         if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
3793                 /* During recovery devices cannot be removed, so
3794                  * locking and refcounting of rdevs is not needed
3795                  */
3796                 rcu_read_lock();
3797                 for (i = 0; i < conf->raid_disks; i++) {
3798                         struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
3799                         if (rdev
3800                             && !test_bit(Faulty, &rdev->flags)
3801                             && !test_bit(In_sync, &rdev->flags)
3802                             && !rdev_set_badblocks(rdev, sh->sector,
3803                                                    RAID5_STRIPE_SECTORS(conf), 0))
3804                                 abort = 1;
3805                         rdev = rcu_dereference(conf->disks[i].replacement);
3806                         if (rdev
3807                             && !test_bit(Faulty, &rdev->flags)
3808                             && !test_bit(In_sync, &rdev->flags)
3809                             && !rdev_set_badblocks(rdev, sh->sector,
3810                                                    RAID5_STRIPE_SECTORS(conf), 0))
3811                                 abort = 1;
3812                 }
3813                 rcu_read_unlock();
3814                 if (abort)
3815                         conf->recovery_disabled =
3816                                 conf->mddev->recovery_disabled;
3817         }
3818         md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), !abort);
3819 }
3820
3821 static int want_replace(struct stripe_head *sh, int disk_idx)
3822 {
3823         struct md_rdev *rdev;
3824         int rv = 0;
3825
3826         rcu_read_lock();
3827         rdev = rcu_dereference(sh->raid_conf->disks[disk_idx].replacement);
3828         if (rdev
3829             && !test_bit(Faulty, &rdev->flags)
3830             && !test_bit(In_sync, &rdev->flags)
3831             && (rdev->recovery_offset <= sh->sector
3832                 || rdev->mddev->recovery_cp <= sh->sector))
3833                 rv = 1;
3834         rcu_read_unlock();
3835         return rv;
3836 }
3837
3838 static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
3839                            int disk_idx, int disks)
3840 {
3841         struct r5dev *dev = &sh->dev[disk_idx];
3842         struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
3843                                   &sh->dev[s->failed_num[1]] };
3844         int i;
3845         bool force_rcw = (sh->raid_conf->rmw_level == PARITY_DISABLE_RMW);
3846
3847
3848         if (test_bit(R5_LOCKED, &dev->flags) ||
3849             test_bit(R5_UPTODATE, &dev->flags))
3850                 /* No point reading this as we already have it or have
3851                  * decided to get it.
3852                  */
3853                 return 0;
3854
3855         if (dev->toread ||
3856             (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)))
3857                 /* We need this block to directly satisfy a request */
3858                 return 1;
3859
3860         if (s->syncing || s->expanding ||
3861             (s->replacing && want_replace(sh, disk_idx)))
3862                 /* When syncing, or expanding we read everything.
3863                  * When replacing, we need the replaced block.
3864                  */
3865                 return 1;
3866
3867         if ((s->failed >= 1 && fdev[0]->toread) ||
3868             (s->failed >= 2 && fdev[1]->toread))
3869                 /* If we want to read from a failed device, then
3870                  * we need to actually read every other device.
3871                  */
3872                 return 1;
3873
3874         /* Sometimes neither read-modify-write nor reconstruct-write
3875          * cycles can work.  In those cases we read every block we
3876          * can.  Then the parity-update is certain to have enough to
3877          * work with.
3878          * This can only be a problem when we need to write something,
3879          * and some device has failed.  If either of those tests
3880          * fail we need look no further.
3881          */
3882         if (!s->failed || !s->to_write)
3883                 return 0;
3884
3885         if (test_bit(R5_Insync, &dev->flags) &&
3886             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3887                 /* Pre-reads at not permitted until after short delay
3888                  * to gather multiple requests.  However if this
3889                  * device is no Insync, the block could only be computed
3890                  * and there is no need to delay that.
3891                  */
3892                 return 0;
3893
3894         for (i = 0; i < s->failed && i < 2; i++) {
3895                 if (fdev[i]->towrite &&
3896                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3897                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3898                         /* If we have a partial write to a failed
3899                          * device, then we will need to reconstruct
3900                          * the content of that device, so all other
3901                          * devices must be read.
3902                          */
3903                         return 1;
3904
3905                 if (s->failed >= 2 &&
3906                     (fdev[i]->towrite ||
3907                      s->failed_num[i] == sh->pd_idx ||
3908                      s->failed_num[i] == sh->qd_idx) &&
3909                     !test_bit(R5_UPTODATE, &fdev[i]->flags))
3910                         /* In max degraded raid6, If the failed disk is P, Q,
3911                          * or we want to read the failed disk, we need to do
3912                          * reconstruct-write.
3913                          */
3914                         force_rcw = true;
3915         }
3916
3917         /* If we are forced to do a reconstruct-write, because parity
3918          * cannot be trusted and we are currently recovering it, there
3919          * is extra need to be careful.
3920          * If one of the devices that we would need to read, because
3921          * it is not being overwritten (and maybe not written at all)
3922          * is missing/faulty, then we need to read everything we can.
3923          */
3924         if (!force_rcw &&
3925             sh->sector < sh->raid_conf->mddev->recovery_cp)
3926                 /* reconstruct-write isn't being forced */
3927                 return 0;
3928         for (i = 0; i < s->failed && i < 2; i++) {
3929                 if (s->failed_num[i] != sh->pd_idx &&
3930                     s->failed_num[i] != sh->qd_idx &&
3931                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3932                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3933                         return 1;
3934         }
3935
3936         return 0;
3937 }
3938
3939 /* fetch_block - checks the given member device to see if its data needs
3940  * to be read or computed to satisfy a request.
3941  *
3942  * Returns 1 when no more member devices need to be checked, otherwise returns
3943  * 0 to tell the loop in handle_stripe_fill to continue
3944  */
3945 static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
3946                        int disk_idx, int disks)
3947 {
3948         struct r5dev *dev = &sh->dev[disk_idx];
3949
3950         /* is the data in this block needed, and can we get it? */
3951         if (need_this_block(sh, s, disk_idx, disks)) {
3952                 /* we would like to get this block, possibly by computing it,
3953                  * otherwise read it if the backing disk is insync
3954                  */
3955                 BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
3956                 BUG_ON(test_bit(R5_Wantread, &dev->flags));
3957                 BUG_ON(sh->batch_head);
3958
3959                 /*
3960                  * In the raid6 case if the only non-uptodate disk is P
3961                  * then we already trusted P to compute the other failed
3962                  * drives. It is safe to compute rather than re-read P.
3963                  * In other cases we only compute blocks from failed
3964                  * devices, otherwise check/repair might fail to detect
3965                  * a real inconsistency.
3966                  */
3967
3968                 if ((s->uptodate == disks - 1) &&
3969                     ((sh->qd_idx >= 0 && sh->pd_idx == disk_idx) ||
3970                     (s->failed && (disk_idx == s->failed_num[0] ||
3971                                    disk_idx == s->failed_num[1])))) {
3972                         /* have disk failed, and we're requested to fetch it;
3973                          * do compute it
3974                          */
3975                         pr_debug("Computing stripe %llu block %d\n",
3976                                (unsigned long long)sh->sector, disk_idx);
3977                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3978                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3979                         set_bit(R5_Wantcompute, &dev->flags);
3980                         sh->ops.target = disk_idx;
3981                         sh->ops.target2 = -1; /* no 2nd target */
3982                         s->req_compute = 1;
3983                         /* Careful: from this point on 'uptodate' is in the eye
3984                          * of raid_run_ops which services 'compute' operations
3985                          * before writes. R5_Wantcompute flags a block that will
3986                          * be R5_UPTODATE by the time it is needed for a
3987                          * subsequent operation.
3988                          */
3989                         s->uptodate++;
3990                         return 1;
3991                 } else if (s->uptodate == disks-2 && s->failed >= 2) {
3992                         /* Computing 2-failure is *very* expensive; only
3993                          * do it if failed >= 2
3994                          */
3995                         int other;
3996                         for (other = disks; other--; ) {
3997                                 if (other == disk_idx)
3998                                         continue;
3999                                 if (!test_bit(R5_UPTODATE,
4000                                       &sh->dev[other].flags))
4001                                         break;
4002                         }
4003                         BUG_ON(other < 0);
4004                         pr_debug("Computing stripe %llu blocks %d,%d\n",
4005                                (unsigned long long)sh->sector,
4006                                disk_idx, other);
4007                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4008                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4009                         set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
4010                         set_bit(R5_Wantcompute, &sh->dev[other].flags);
4011                         sh->ops.target = disk_idx;
4012                         sh->ops.target2 = other;
4013                         s->uptodate += 2;
4014                         s->req_compute = 1;
4015                         return 1;
4016                 } else if (test_bit(R5_Insync, &dev->flags)) {
4017                         set_bit(R5_LOCKED, &dev->flags);
4018                         set_bit(R5_Wantread, &dev->flags);
4019                         s->locked++;
4020                         pr_debug("Reading block %d (sync=%d)\n",
4021                                 disk_idx, s->syncing);
4022                 }
4023         }
4024
4025         return 0;
4026 }
4027
4028 /*
4029  * handle_stripe_fill - read or compute data to satisfy pending requests.
4030  */
4031 static void handle_stripe_fill(struct stripe_head *sh,
4032                                struct stripe_head_state *s,
4033                                int disks)
4034 {
4035         int i;
4036
4037         /* look for blocks to read/compute, skip this if a compute
4038          * is already in flight, or if the stripe contents are in the
4039          * midst of changing due to a write
4040          */
4041         if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
4042             !sh->reconstruct_state) {
4043
4044                 /*
4045                  * For degraded stripe with data in journal, do not handle
4046                  * read requests yet, instead, flush the stripe to raid
4047                  * disks first, this avoids handling complex rmw of write
4048                  * back cache (prexor with orig_page, and then xor with
4049                  * page) in the read path
4050                  */
4051                 if (s->to_read && s->injournal && s->failed) {
4052                         if (test_bit(STRIPE_R5C_CACHING, &sh->state))
4053                                 r5c_make_stripe_write_out(sh);
4054                         goto out;
4055                 }
4056
4057                 for (i = disks; i--; )
4058                         if (fetch_block(sh, s, i, disks))
4059                                 break;
4060         }
4061 out:
4062         set_bit(STRIPE_HANDLE, &sh->state);
4063 }
4064
4065 static void break_stripe_batch_list(struct stripe_head *head_sh,
4066                                     unsigned long handle_flags);
4067 /* handle_stripe_clean_event
4068  * any written block on an uptodate or failed drive can be returned.
4069  * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
4070  * never LOCKED, so we don't need to test 'failed' directly.
4071  */
4072 static void handle_stripe_clean_event(struct r5conf *conf,
4073         struct stripe_head *sh, int disks)
4074 {
4075         int i;
4076         struct r5dev *dev;
4077         int discard_pending = 0;
4078         struct stripe_head *head_sh = sh;
4079         bool do_endio = false;
4080
4081         for (i = disks; i--; )
4082                 if (sh->dev[i].written) {
4083                         dev = &sh->dev[i];
4084                         if (!test_bit(R5_LOCKED, &dev->flags) &&
4085                             (test_bit(R5_UPTODATE, &dev->flags) ||
4086                              test_bit(R5_Discard, &dev->flags) ||
4087                              test_bit(R5_SkipCopy, &dev->flags))) {
4088                                 /* We can return any write requests */
4089                                 struct bio *wbi, *wbi2;
4090                                 pr_debug("Return write for disc %d\n", i);
4091                                 if (test_and_clear_bit(R5_Discard, &dev->flags))
4092                                         clear_bit(R5_UPTODATE, &dev->flags);
4093                                 if (test_and_clear_bit(R5_SkipCopy, &dev->flags)) {
4094                                         WARN_ON(test_bit(R5_UPTODATE, &dev->flags));
4095                                 }
4096                                 do_endio = true;
4097
4098 returnbi:
4099                                 dev->page = dev->orig_page;
4100                                 wbi = dev->written;
4101                                 dev->written = NULL;
4102                                 while (wbi && wbi->bi_iter.bi_sector <
4103                                         dev->sector + RAID5_STRIPE_SECTORS(conf)) {
4104                                         wbi2 = r5_next_bio(conf, wbi, dev->sector);
4105                                         md_write_end(conf->mddev);
4106                                         bio_endio(wbi);
4107                                         wbi = wbi2;
4108                                 }
4109                                 md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
4110                                                    RAID5_STRIPE_SECTORS(conf),
4111                                                    !test_bit(STRIPE_DEGRADED, &sh->state),
4112                                                    0);
4113                                 if (head_sh->batch_head) {
4114                                         sh = list_first_entry(&sh->batch_list,
4115                                                               struct stripe_head,
4116                                                               batch_list);
4117                                         if (sh != head_sh) {
4118                                                 dev = &sh->dev[i];
4119                                                 goto returnbi;
4120                                         }
4121                                 }
4122                                 sh = head_sh;
4123                                 dev = &sh->dev[i];
4124                         } else if (test_bit(R5_Discard, &dev->flags))
4125                                 discard_pending = 1;
4126                 }
4127
4128         log_stripe_write_finished(sh);
4129
4130         if (!discard_pending &&
4131             test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) {
4132                 int hash;
4133                 clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
4134                 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4135                 if (sh->qd_idx >= 0) {
4136                         clear_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
4137                         clear_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags);
4138                 }
4139                 /* now that discard is done we can proceed with any sync */
4140                 clear_bit(STRIPE_DISCARD, &sh->state);
4141                 /*
4142                  * SCSI discard will change some bio fields and the stripe has
4143                  * no updated data, so remove it from hash list and the stripe
4144                  * will be reinitialized
4145                  */
4146 unhash:
4147                 hash = sh->hash_lock_index;
4148                 spin_lock_irq(conf->hash_locks + hash);
4149                 remove_hash(sh);
4150                 spin_unlock_irq(conf->hash_locks + hash);
4151                 if (head_sh->batch_head) {
4152                         sh = list_first_entry(&sh->batch_list,
4153                                               struct stripe_head, batch_list);
4154                         if (sh != head_sh)
4155                                         goto unhash;
4156                 }
4157                 sh = head_sh;
4158
4159                 if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
4160                         set_bit(STRIPE_HANDLE, &sh->state);
4161
4162         }
4163
4164         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
4165                 if (atomic_dec_and_test(&conf->pending_full_writes))
4166                         md_wakeup_thread(conf->mddev->thread);
4167
4168         if (head_sh->batch_head && do_endio)
4169                 break_stripe_batch_list(head_sh, STRIPE_EXPAND_SYNC_FLAGS);
4170 }
4171
4172 /*
4173  * For RMW in write back cache, we need extra page in prexor to store the
4174  * old data. This page is stored in dev->orig_page.
4175  *
4176  * This function checks whether we have data for prexor. The exact logic
4177  * is:
4178  *       R5_UPTODATE && (!R5_InJournal || R5_OrigPageUPTDODATE)
4179  */
4180 static inline bool uptodate_for_rmw(struct r5dev *dev)
4181 {
4182         return (test_bit(R5_UPTODATE, &dev->flags)) &&
4183                 (!test_bit(R5_InJournal, &dev->flags) ||
4184                  test_bit(R5_OrigPageUPTDODATE, &dev->flags));
4185 }
4186
4187 static int handle_stripe_dirtying(struct r5conf *conf,
4188                                   struct stripe_head *sh,
4189                                   struct stripe_head_state *s,
4190                                   int disks)
4191 {
4192         int rmw = 0, rcw = 0, i;
4193         sector_t recovery_cp = conf->mddev->recovery_cp;
4194
4195         /* Check whether resync is now happening or should start.
4196          * If yes, then the array is dirty (after unclean shutdown or
4197          * initial creation), so parity in some stripes might be inconsistent.
4198          * In this case, we need to always do reconstruct-write, to ensure
4199          * that in case of drive failure or read-error correction, we
4200          * generate correct data from the parity.
4201          */
4202         if (conf->rmw_level == PARITY_DISABLE_RMW ||
4203             (recovery_cp < MaxSector && sh->sector >= recovery_cp &&
4204              s->failed == 0)) {
4205                 /* Calculate the real rcw later - for now make it
4206                  * look like rcw is cheaper
4207                  */
4208                 rcw = 1; rmw = 2;
4209                 pr_debug("force RCW rmw_level=%u, recovery_cp=%llu sh->sector=%llu\n",
4210                          conf->rmw_level, (unsigned long long)recovery_cp,
4211                          (unsigned long long)sh->sector);
4212         } else for (i = disks; i--; ) {
4213                 /* would I have to read this buffer for read_modify_write */
4214                 struct r5dev *dev = &sh->dev[i];
4215                 if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
4216                      i == sh->pd_idx || i == sh->qd_idx ||
4217                      test_bit(R5_InJournal, &dev->flags)) &&
4218                     !test_bit(R5_LOCKED, &dev->flags) &&
4219                     !(uptodate_for_rmw(dev) ||
4220                       test_bit(R5_Wantcompute, &dev->flags))) {
4221                         if (test_bit(R5_Insync, &dev->flags))
4222                                 rmw++;
4223                         else
4224                                 rmw += 2*disks;  /* cannot read it */
4225                 }
4226                 /* Would I have to read this buffer for reconstruct_write */
4227                 if (!test_bit(R5_OVERWRITE, &dev->flags) &&
4228                     i != sh->pd_idx && i != sh->qd_idx &&
4229                     !test_bit(R5_LOCKED, &dev->flags) &&
4230                     !(test_bit(R5_UPTODATE, &dev->flags) ||
4231                       test_bit(R5_Wantcompute, &dev->flags))) {
4232                         if (test_bit(R5_Insync, &dev->flags))
4233                                 rcw++;
4234                         else
4235                                 rcw += 2*disks;
4236                 }
4237         }
4238
4239         pr_debug("for sector %llu state 0x%lx, rmw=%d rcw=%d\n",
4240                  (unsigned long long)sh->sector, sh->state, rmw, rcw);
4241         set_bit(STRIPE_HANDLE, &sh->state);
4242         if ((rmw < rcw || (rmw == rcw && conf->rmw_level == PARITY_PREFER_RMW)) && rmw > 0) {
4243                 /* prefer read-modify-write, but need to get some data */
4244                 if (conf->mddev->queue)
4245                         blk_add_trace_msg(conf->mddev->queue,
4246                                           "raid5 rmw %llu %d",
4247                                           (unsigned long long)sh->sector, rmw);
4248                 for (i = disks; i--; ) {
4249                         struct r5dev *dev = &sh->dev[i];
4250                         if (test_bit(R5_InJournal, &dev->flags) &&
4251                             dev->page == dev->orig_page &&
4252                             !test_bit(R5_LOCKED, &sh->dev[sh->pd_idx].flags)) {
4253                                 /* alloc page for prexor */
4254                                 struct page *p = alloc_page(GFP_NOIO);
4255
4256                                 if (p) {
4257                                         dev->orig_page = p;
4258                                         continue;
4259                                 }
4260
4261                                 /*
4262                                  * alloc_page() failed, try use
4263                                  * disk_info->extra_page
4264                                  */
4265                                 if (!test_and_set_bit(R5C_EXTRA_PAGE_IN_USE,
4266                                                       &conf->cache_state)) {
4267                                         r5c_use_extra_page(sh);
4268                                         break;
4269                                 }
4270
4271                                 /* extra_page in use, add to delayed_list */
4272                                 set_bit(STRIPE_DELAYED, &sh->state);
4273                                 s->waiting_extra_page = 1;
4274                                 return -EAGAIN;
4275                         }
4276                 }
4277
4278                 for (i = disks; i--; ) {
4279                         struct r5dev *dev = &sh->dev[i];
4280                         if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
4281                              i == sh->pd_idx || i == sh->qd_idx ||
4282                              test_bit(R5_InJournal, &dev->flags)) &&
4283                             !test_bit(R5_LOCKED, &dev->flags) &&
4284                             !(uptodate_for_rmw(dev) ||
4285                               test_bit(R5_Wantcompute, &dev->flags)) &&
4286                             test_bit(R5_Insync, &dev->flags)) {
4287                                 if (test_bit(STRIPE_PREREAD_ACTIVE,
4288                                              &sh->state)) {
4289                                         pr_debug("Read_old block %d for r-m-w\n",
4290                                                  i);
4291                                         set_bit(R5_LOCKED, &dev->flags);
4292                                         set_bit(R5_Wantread, &dev->flags);
4293                                         s->locked++;
4294                                 } else
4295                                         set_bit(STRIPE_DELAYED, &sh->state);
4296                         }
4297                 }
4298         }
4299         if ((rcw < rmw || (rcw == rmw && conf->rmw_level != PARITY_PREFER_RMW)) && rcw > 0) {
4300                 /* want reconstruct write, but need to get some data */
4301                 int qread =0;
4302                 rcw = 0;
4303                 for (i = disks; i--; ) {
4304                         struct r5dev *dev = &sh->dev[i];
4305                         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
4306                             i != sh->pd_idx && i != sh->qd_idx &&
4307                             !test_bit(R5_LOCKED, &dev->flags) &&
4308                             !(test_bit(R5_UPTODATE, &dev->flags) ||
4309                               test_bit(R5_Wantcompute, &dev->flags))) {
4310                                 rcw++;
4311                                 if (test_bit(R5_Insync, &dev->flags) &&
4312                                     test_bit(STRIPE_PREREAD_ACTIVE,
4313                                              &sh->state)) {
4314                                         pr_debug("Read_old block "
4315                                                 "%d for Reconstruct\n", i);
4316                                         set_bit(R5_LOCKED, &dev->flags);
4317                                         set_bit(R5_Wantread, &dev->flags);
4318                                         s->locked++;
4319                                         qread++;
4320                                 } else
4321                                         set_bit(STRIPE_DELAYED, &sh->state);
4322                         }
4323                 }
4324                 if (rcw && conf->mddev->queue)
4325                         blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
4326                                           (unsigned long long)sh->sector,
4327                                           rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
4328         }
4329
4330         if (rcw > disks && rmw > disks &&
4331             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4332                 set_bit(STRIPE_DELAYED, &sh->state);
4333
4334         /* now if nothing is locked, and if we have enough data,
4335          * we can start a write request
4336          */
4337         /* since handle_stripe can be called at any time we need to handle the
4338          * case where a compute block operation has been submitted and then a
4339          * subsequent call wants to start a write request.  raid_run_ops only
4340          * handles the case where compute block and reconstruct are requested
4341          * simultaneously.  If this is not the case then new writes need to be
4342          * held off until the compute completes.
4343          */
4344         if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
4345             (s->locked == 0 && (rcw == 0 || rmw == 0) &&
4346              !test_bit(STRIPE_BIT_DELAY, &sh->state)))
4347                 schedule_reconstruction(sh, s, rcw == 0, 0);
4348         return 0;
4349 }
4350
4351 static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
4352                                 struct stripe_head_state *s, int disks)
4353 {
4354         struct r5dev *dev = NULL;
4355
4356         BUG_ON(sh->batch_head);
4357         set_bit(STRIPE_HANDLE, &sh->state);
4358
4359         switch (sh->check_state) {
4360         case check_state_idle:
4361                 /* start a new check operation if there are no failures */
4362                 if (s->failed == 0) {
4363                         BUG_ON(s->uptodate != disks);
4364                         sh->check_state = check_state_run;
4365                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4366                         clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4367                         s->uptodate--;
4368                         break;
4369                 }
4370                 dev = &sh->dev[s->failed_num[0]];
4371                 fallthrough;
4372         case check_state_compute_result:
4373                 sh->check_state = check_state_idle;
4374                 if (!dev)
4375                         dev = &sh->dev[sh->pd_idx];
4376
4377                 /* check that a write has not made the stripe insync */
4378                 if (test_bit(STRIPE_INSYNC, &sh->state))
4379                         break;
4380
4381                 /* either failed parity check, or recovery is happening */
4382                 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
4383                 BUG_ON(s->uptodate != disks);
4384
4385                 set_bit(R5_LOCKED, &dev->flags);
4386                 s->locked++;
4387                 set_bit(R5_Wantwrite, &dev->flags);
4388
4389                 clear_bit(STRIPE_DEGRADED, &sh->state);
4390                 set_bit(STRIPE_INSYNC, &sh->state);
4391                 break;
4392         case check_state_run:
4393                 break; /* we will be called again upon completion */
4394         case check_state_check_result:
4395                 sh->check_state = check_state_idle;
4396
4397                 /* if a failure occurred during the check operation, leave
4398                  * STRIPE_INSYNC not set and let the stripe be handled again
4399                  */
4400                 if (s->failed)
4401                         break;
4402
4403                 /* handle a successful check operation, if parity is correct
4404                  * we are done.  Otherwise update the mismatch count and repair
4405                  * parity if !MD_RECOVERY_CHECK
4406                  */
4407                 if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
4408                         /* parity is correct (on disc,
4409                          * not in buffer any more)
4410                          */
4411                         set_bit(STRIPE_INSYNC, &sh->state);
4412                 else {
4413                         atomic64_add(RAID5_STRIPE_SECTORS(conf), &conf->mddev->resync_mismatches);
4414                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4415                                 /* don't try to repair!! */
4416                                 set_bit(STRIPE_INSYNC, &sh->state);
4417                                 pr_warn_ratelimited("%s: mismatch sector in range "
4418                                                     "%llu-%llu\n", mdname(conf->mddev),
4419                                                     (unsigned long long) sh->sector,
4420                                                     (unsigned long long) sh->sector +
4421                                                     RAID5_STRIPE_SECTORS(conf));
4422                         } else {
4423                                 sh->check_state = check_state_compute_run;
4424                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4425                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4426                                 set_bit(R5_Wantcompute,
4427                                         &sh->dev[sh->pd_idx].flags);
4428                                 sh->ops.target = sh->pd_idx;
4429                                 sh->ops.target2 = -1;
4430                                 s->uptodate++;
4431                         }
4432                 }
4433                 break;
4434         case check_state_compute_run:
4435                 break;
4436         default:
4437                 pr_err("%s: unknown check_state: %d sector: %llu\n",
4438                        __func__, sh->check_state,
4439                        (unsigned long long) sh->sector);
4440                 BUG();
4441         }
4442 }
4443
4444 static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
4445                                   struct stripe_head_state *s,
4446                                   int disks)
4447 {
4448         int pd_idx = sh->pd_idx;
4449         int qd_idx = sh->qd_idx;
4450         struct r5dev *dev;
4451
4452         BUG_ON(sh->batch_head);
4453         set_bit(STRIPE_HANDLE, &sh->state);
4454
4455         BUG_ON(s->failed > 2);
4456
4457         /* Want to check and possibly repair P and Q.
4458          * However there could be one 'failed' device, in which
4459          * case we can only check one of them, possibly using the
4460          * other to generate missing data
4461          */
4462
4463         switch (sh->check_state) {
4464         case check_state_idle:
4465                 /* start a new check operation if there are < 2 failures */
4466                 if (s->failed == s->q_failed) {
4467                         /* The only possible failed device holds Q, so it
4468                          * makes sense to check P (If anything else were failed,
4469                          * we would have used P to recreate it).
4470                          */
4471                         sh->check_state = check_state_run;
4472                 }
4473                 if (!s->q_failed && s->failed < 2) {
4474                         /* Q is not failed, and we didn't use it to generate
4475                          * anything, so it makes sense to check it
4476                          */
4477                         if (sh->check_state == check_state_run)
4478                                 sh->check_state = check_state_run_pq;
4479                         else
4480                                 sh->check_state = check_state_run_q;
4481                 }
4482
4483                 /* discard potentially stale zero_sum_result */
4484                 sh->ops.zero_sum_result = 0;
4485
4486                 if (sh->check_state == check_state_run) {
4487                         /* async_xor_zero_sum destroys the contents of P */
4488                         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
4489                         s->uptodate--;
4490                 }
4491                 if (sh->check_state >= check_state_run &&
4492                     sh->check_state <= check_state_run_pq) {
4493                         /* async_syndrome_zero_sum preserves P and Q, so
4494                          * no need to mark them !uptodate here
4495                          */
4496                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4497                         break;
4498                 }
4499
4500                 /* we have 2-disk failure */
4501                 BUG_ON(s->failed != 2);
4502                 fallthrough;
4503         case check_state_compute_result:
4504                 sh->check_state = check_state_idle;
4505
4506                 /* check that a write has not made the stripe insync */
4507                 if (test_bit(STRIPE_INSYNC, &sh->state))
4508                         break;
4509
4510                 /* now write out any block on a failed drive,
4511                  * or P or Q if they were recomputed
4512                  */
4513                 dev = NULL;
4514                 if (s->failed == 2) {
4515                         dev = &sh->dev[s->failed_num[1]];
4516                         s->locked++;
4517                         set_bit(R5_LOCKED, &dev->flags);
4518                         set_bit(R5_Wantwrite, &dev->flags);
4519                 }
4520                 if (s->failed >= 1) {
4521                         dev = &sh->dev[s->failed_num[0]];
4522                         s->locked++;
4523                         set_bit(R5_LOCKED, &dev->flags);
4524                         set_bit(R5_Wantwrite, &dev->flags);
4525                 }
4526                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4527                         dev = &sh->dev[pd_idx];
4528                         s->locked++;
4529                         set_bit(R5_LOCKED, &dev->flags);
4530                         set_bit(R5_Wantwrite, &dev->flags);
4531                 }
4532                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4533                         dev = &sh->dev[qd_idx];
4534                         s->locked++;
4535                         set_bit(R5_LOCKED, &dev->flags);
4536                         set_bit(R5_Wantwrite, &dev->flags);
4537                 }
4538                 if (WARN_ONCE(dev && !test_bit(R5_UPTODATE, &dev->flags),
4539                               "%s: disk%td not up to date\n",
4540                               mdname(conf->mddev),
4541                               dev - (struct r5dev *) &sh->dev)) {
4542                         clear_bit(R5_LOCKED, &dev->flags);
4543                         clear_bit(R5_Wantwrite, &dev->flags);
4544                         s->locked--;
4545                 }
4546                 clear_bit(STRIPE_DEGRADED, &sh->state);
4547
4548                 set_bit(STRIPE_INSYNC, &sh->state);
4549                 break;
4550         case check_state_run:
4551         case check_state_run_q:
4552         case check_state_run_pq:
4553                 break; /* we will be called again upon completion */
4554         case check_state_check_result:
4555                 sh->check_state = check_state_idle;
4556
4557                 /* handle a successful check operation, if parity is correct
4558                  * we are done.  Otherwise update the mismatch count and repair
4559                  * parity if !MD_RECOVERY_CHECK
4560                  */
4561                 if (sh->ops.zero_sum_result == 0) {
4562                         /* both parities are correct */
4563                         if (!s->failed)
4564                                 set_bit(STRIPE_INSYNC, &sh->state);
4565                         else {
4566                                 /* in contrast to the raid5 case we can validate
4567                                  * parity, but still have a failure to write
4568                                  * back
4569                                  */
4570                                 sh->check_state = check_state_compute_result;
4571                                 /* Returning at this point means that we may go
4572                                  * off and bring p and/or q uptodate again so
4573                                  * we make sure to check zero_sum_result again
4574                                  * to verify if p or q need writeback
4575                                  */
4576                         }
4577                 } else {
4578                         atomic64_add(RAID5_STRIPE_SECTORS(conf), &conf->mddev->resync_mismatches);
4579                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4580                                 /* don't try to repair!! */
4581                                 set_bit(STRIPE_INSYNC, &sh->state);
4582                                 pr_warn_ratelimited("%s: mismatch sector in range "
4583                                                     "%llu-%llu\n", mdname(conf->mddev),
4584                                                     (unsigned long long) sh->sector,
4585                                                     (unsigned long long) sh->sector +
4586                                                     RAID5_STRIPE_SECTORS(conf));
4587                         } else {
4588                                 int *target = &sh->ops.target;
4589
4590                                 sh->ops.target = -1;
4591                                 sh->ops.target2 = -1;
4592                                 sh->check_state = check_state_compute_run;
4593                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4594                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4595                                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4596                                         set_bit(R5_Wantcompute,
4597                                                 &sh->dev[pd_idx].flags);
4598                                         *target = pd_idx;
4599                                         target = &sh->ops.target2;
4600                                         s->uptodate++;
4601                                 }
4602                                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4603                                         set_bit(R5_Wantcompute,
4604                                                 &sh->dev[qd_idx].flags);
4605                                         *target = qd_idx;
4606                                         s->uptodate++;
4607                                 }
4608                         }
4609                 }
4610                 break;
4611         case check_state_compute_run:
4612                 break;
4613         default:
4614                 pr_warn("%s: unknown check_state: %d sector: %llu\n",
4615                         __func__, sh->check_state,
4616                         (unsigned long long) sh->sector);
4617                 BUG();
4618         }
4619 }
4620
4621 static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
4622 {
4623         int i;
4624
4625         /* We have read all the blocks in this stripe and now we need to
4626          * copy some of them into a target stripe for expand.
4627          */
4628         struct dma_async_tx_descriptor *tx = NULL;
4629         BUG_ON(sh->batch_head);
4630         clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
4631         for (i = 0; i < sh->disks; i++)
4632                 if (i != sh->pd_idx && i != sh->qd_idx) {
4633                         int dd_idx, j;
4634                         struct stripe_head *sh2;
4635                         struct async_submit_ctl submit;
4636
4637                         sector_t bn = raid5_compute_blocknr(sh, i, 1);
4638                         sector_t s = raid5_compute_sector(conf, bn, 0,
4639                                                           &dd_idx, NULL);
4640                         sh2 = raid5_get_active_stripe(conf, NULL, s,
4641                                 R5_GAS_NOBLOCK | R5_GAS_NOQUIESCE);
4642                         if (sh2 == NULL)
4643                                 /* so far only the early blocks of this stripe
4644                                  * have been requested.  When later blocks
4645                                  * get requested, we will try again
4646                                  */
4647                                 continue;
4648                         if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
4649                            test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
4650                                 /* must have already done this block */
4651                                 raid5_release_stripe(sh2);
4652                                 continue;
4653                         }
4654
4655                         /* place all the copies on one channel */
4656                         init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
4657                         tx = async_memcpy(sh2->dev[dd_idx].page,
4658                                           sh->dev[i].page, sh2->dev[dd_idx].offset,
4659                                           sh->dev[i].offset, RAID5_STRIPE_SIZE(conf),
4660                                           &submit);
4661
4662                         set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
4663                         set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
4664                         for (j = 0; j < conf->raid_disks; j++)
4665                                 if (j != sh2->pd_idx &&
4666                                     j != sh2->qd_idx &&
4667                                     !test_bit(R5_Expanded, &sh2->dev[j].flags))
4668                                         break;
4669                         if (j == conf->raid_disks) {
4670                                 set_bit(STRIPE_EXPAND_READY, &sh2->state);
4671                                 set_bit(STRIPE_HANDLE, &sh2->state);
4672                         }
4673                         raid5_release_stripe(sh2);
4674
4675                 }
4676         /* done submitting copies, wait for them to complete */
4677         async_tx_quiesce(&tx);
4678 }
4679
4680 /*
4681  * handle_stripe - do things to a stripe.
4682  *
4683  * We lock the stripe by setting STRIPE_ACTIVE and then examine the
4684  * state of various bits to see what needs to be done.
4685  * Possible results:
4686  *    return some read requests which now have data
4687  *    return some write requests which are safely on storage
4688  *    schedule a read on some buffers
4689  *    schedule a write of some buffers
4690  *    return confirmation of parity correctness
4691  *
4692  */
4693
4694 static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
4695 {
4696         struct r5conf *conf = sh->raid_conf;
4697         int disks = sh->disks;
4698         struct r5dev *dev;
4699         int i;
4700         int do_recovery = 0;
4701
4702         memset(s, 0, sizeof(*s));
4703
4704         s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state) && !sh->batch_head;
4705         s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state) && !sh->batch_head;
4706         s->failed_num[0] = -1;
4707         s->failed_num[1] = -1;
4708         s->log_failed = r5l_log_disk_error(conf);
4709
4710         /* Now to look around and see what can be done */
4711         rcu_read_lock();
4712         for (i=disks; i--; ) {
4713                 struct md_rdev *rdev;
4714                 sector_t first_bad;
4715                 int bad_sectors;
4716                 int is_bad = 0;
4717
4718                 dev = &sh->dev[i];
4719
4720                 pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
4721                          i, dev->flags,
4722                          dev->toread, dev->towrite, dev->written);
4723                 /* maybe we can reply to a read
4724                  *
4725                  * new wantfill requests are only permitted while
4726                  * ops_complete_biofill is guaranteed to be inactive
4727                  */
4728                 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
4729                     !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
4730                         set_bit(R5_Wantfill, &dev->flags);
4731
4732                 /* now count some things */
4733                 if (test_bit(R5_LOCKED, &dev->flags))
4734                         s->locked++;
4735                 if (test_bit(R5_UPTODATE, &dev->flags))
4736                         s->uptodate++;
4737                 if (test_bit(R5_Wantcompute, &dev->flags)) {
4738                         s->compute++;
4739                         BUG_ON(s->compute > 2);
4740                 }
4741
4742                 if (test_bit(R5_Wantfill, &dev->flags))
4743                         s->to_fill++;
4744                 else if (dev->toread)
4745                         s->to_read++;
4746                 if (dev->towrite) {
4747                         s->to_write++;
4748                         if (!test_bit(R5_OVERWRITE, &dev->flags))
4749                                 s->non_overwrite++;
4750                 }
4751                 if (dev->written)
4752                         s->written++;
4753                 /* Prefer to use the replacement for reads, but only
4754                  * if it is recovered enough and has no bad blocks.
4755                  */
4756                 rdev = rcu_dereference(conf->disks[i].replacement);
4757                 if (rdev && !test_bit(Faulty, &rdev->flags) &&
4758                     rdev->recovery_offset >= sh->sector + RAID5_STRIPE_SECTORS(conf) &&
4759                     !is_badblock(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf),
4760                                  &first_bad, &bad_sectors))
4761                         set_bit(R5_ReadRepl, &dev->flags);
4762                 else {
4763                         if (rdev && !test_bit(Faulty, &rdev->flags))
4764                                 set_bit(R5_NeedReplace, &dev->flags);
4765                         else
4766                                 clear_bit(R5_NeedReplace, &dev->flags);
4767                         rdev = rcu_dereference(conf->disks[i].rdev);
4768                         clear_bit(R5_ReadRepl, &dev->flags);
4769                 }
4770                 if (rdev && test_bit(Faulty, &rdev->flags))
4771                         rdev = NULL;
4772                 if (rdev) {
4773                         is_bad = is_badblock(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf),
4774                                              &first_bad, &bad_sectors);
4775                         if (s->blocked_rdev == NULL
4776                             && (test_bit(Blocked, &rdev->flags)
4777                                 || is_bad < 0)) {
4778                                 if (is_bad < 0)
4779                                         set_bit(BlockedBadBlocks,
4780                                                 &rdev->flags);
4781                                 s->blocked_rdev = rdev;
4782                                 atomic_inc(&rdev->nr_pending);
4783                         }
4784                 }
4785                 clear_bit(R5_Insync, &dev->flags);
4786                 if (!rdev)
4787                         /* Not in-sync */;
4788                 else if (is_bad) {
4789                         /* also not in-sync */
4790                         if (!test_bit(WriteErrorSeen, &rdev->flags) &&
4791                             test_bit(R5_UPTODATE, &dev->flags)) {
4792                                 /* treat as in-sync, but with a read error
4793                                  * which we can now try to correct
4794                                  */
4795                                 set_bit(R5_Insync, &dev->flags);
4796                                 set_bit(R5_ReadError, &dev->flags);
4797                         }
4798                 } else if (test_bit(In_sync, &rdev->flags))
4799                         set_bit(R5_Insync, &dev->flags);
4800                 else if (sh->sector + RAID5_STRIPE_SECTORS(conf) <= rdev->recovery_offset)
4801                         /* in sync if before recovery_offset */
4802                         set_bit(R5_Insync, &dev->flags);
4803                 else if (test_bit(R5_UPTODATE, &dev->flags) &&
4804                          test_bit(R5_Expanded, &dev->flags))
4805                         /* If we've reshaped into here, we assume it is Insync.
4806                          * We will shortly update recovery_offset to make
4807                          * it official.
4808                          */
4809                         set_bit(R5_Insync, &dev->flags);
4810
4811                 if (test_bit(R5_WriteError, &dev->flags)) {
4812                         /* This flag does not apply to '.replacement'
4813                          * only to .rdev, so make sure to check that*/
4814                         struct md_rdev *rdev2 = rcu_dereference(
4815                                 conf->disks[i].rdev);
4816                         if (rdev2 == rdev)
4817                                 clear_bit(R5_Insync, &dev->flags);
4818                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4819                                 s->handle_bad_blocks = 1;
4820                                 atomic_inc(&rdev2->nr_pending);
4821                         } else
4822                                 clear_bit(R5_WriteError, &dev->flags);
4823                 }
4824                 if (test_bit(R5_MadeGood, &dev->flags)) {
4825                         /* This flag does not apply to '.replacement'
4826                          * only to .rdev, so make sure to check that*/
4827                         struct md_rdev *rdev2 = rcu_dereference(
4828                                 conf->disks[i].rdev);
4829                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4830                                 s->handle_bad_blocks = 1;
4831                                 atomic_inc(&rdev2->nr_pending);
4832                         } else
4833                                 clear_bit(R5_MadeGood, &dev->flags);
4834                 }
4835                 if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
4836                         struct md_rdev *rdev2 = rcu_dereference(
4837                                 conf->disks[i].replacement);
4838                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4839                                 s->handle_bad_blocks = 1;
4840                                 atomic_inc(&rdev2->nr_pending);
4841                         } else
4842                                 clear_bit(R5_MadeGoodRepl, &dev->flags);
4843                 }
4844                 if (!test_bit(R5_Insync, &dev->flags)) {
4845                         /* The ReadError flag will just be confusing now */
4846                         clear_bit(R5_ReadError, &dev->flags);
4847                         clear_bit(R5_ReWrite, &dev->flags);
4848                 }
4849                 if (test_bit(R5_ReadError, &dev->flags))
4850                         clear_bit(R5_Insync, &dev->flags);
4851                 if (!test_bit(R5_Insync, &dev->flags)) {
4852                         if (s->failed < 2)
4853                                 s->failed_num[s->failed] = i;
4854                         s->failed++;
4855                         if (rdev && !test_bit(Faulty, &rdev->flags))
4856                                 do_recovery = 1;
4857                         else if (!rdev) {
4858                                 rdev = rcu_dereference(
4859                                     conf->disks[i].replacement);
4860                                 if (rdev && !test_bit(Faulty, &rdev->flags))
4861                                         do_recovery = 1;
4862                         }
4863                 }
4864
4865                 if (test_bit(R5_InJournal, &dev->flags))
4866                         s->injournal++;
4867                 if (test_bit(R5_InJournal, &dev->flags) && dev->written)
4868                         s->just_cached++;
4869         }
4870         if (test_bit(STRIPE_SYNCING, &sh->state)) {
4871                 /* If there is a failed device being replaced,
4872                  *     we must be recovering.
4873                  * else if we are after recovery_cp, we must be syncing
4874                  * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
4875                  * else we can only be replacing
4876                  * sync and recovery both need to read all devices, and so
4877                  * use the same flag.
4878                  */
4879                 if (do_recovery ||
4880                     sh->sector >= conf->mddev->recovery_cp ||
4881                     test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
4882                         s->syncing = 1;
4883                 else
4884                         s->replacing = 1;
4885         }
4886         rcu_read_unlock();
4887 }
4888
4889 /*
4890  * Return '1' if this is a member of batch, or '0' if it is a lone stripe or
4891  * a head which can now be handled.
4892  */
4893 static int clear_batch_ready(struct stripe_head *sh)
4894 {
4895         struct stripe_head *tmp;
4896         if (!test_and_clear_bit(STRIPE_BATCH_READY, &sh->state))
4897                 return (sh->batch_head && sh->batch_head != sh);
4898         spin_lock(&sh->stripe_lock);
4899         if (!sh->batch_head) {
4900                 spin_unlock(&sh->stripe_lock);
4901                 return 0;
4902         }
4903
4904         /*
4905          * this stripe could be added to a batch list before we check
4906          * BATCH_READY, skips it
4907          */
4908         if (sh->batch_head != sh) {
4909                 spin_unlock(&sh->stripe_lock);
4910                 return 1;
4911         }
4912         spin_lock(&sh->batch_lock);
4913         list_for_each_entry(tmp, &sh->batch_list, batch_list)
4914                 clear_bit(STRIPE_BATCH_READY, &tmp->state);
4915         spin_unlock(&sh->batch_lock);
4916         spin_unlock(&sh->stripe_lock);
4917
4918         /*
4919          * BATCH_READY is cleared, no new stripes can be added.
4920          * batch_list can be accessed without lock
4921          */
4922         return 0;
4923 }
4924
4925 static void break_stripe_batch_list(struct stripe_head *head_sh,
4926                                     unsigned long handle_flags)
4927 {
4928         struct stripe_head *sh, *next;
4929         int i;
4930         int do_wakeup = 0;
4931
4932         list_for_each_entry_safe(sh, next, &head_sh->batch_list, batch_list) {
4933
4934                 list_del_init(&sh->batch_list);
4935
4936                 WARN_ONCE(sh->state & ((1 << STRIPE_ACTIVE) |
4937                                           (1 << STRIPE_SYNCING) |
4938                                           (1 << STRIPE_REPLACED) |
4939                                           (1 << STRIPE_DELAYED) |
4940                                           (1 << STRIPE_BIT_DELAY) |
4941                                           (1 << STRIPE_FULL_WRITE) |
4942                                           (1 << STRIPE_BIOFILL_RUN) |
4943                                           (1 << STRIPE_COMPUTE_RUN)  |
4944                                           (1 << STRIPE_DISCARD) |
4945                                           (1 << STRIPE_BATCH_READY) |
4946                                           (1 << STRIPE_BATCH_ERR) |
4947                                           (1 << STRIPE_BITMAP_PENDING)),
4948                         "stripe state: %lx\n", sh->state);
4949                 WARN_ONCE(head_sh->state & ((1 << STRIPE_DISCARD) |
4950                                               (1 << STRIPE_REPLACED)),
4951                         "head stripe state: %lx\n", head_sh->state);
4952
4953                 set_mask_bits(&sh->state, ~(STRIPE_EXPAND_SYNC_FLAGS |
4954                                             (1 << STRIPE_PREREAD_ACTIVE) |
4955                                             (1 << STRIPE_DEGRADED) |
4956                                             (1 << STRIPE_ON_UNPLUG_LIST)),
4957                               head_sh->state & (1 << STRIPE_INSYNC));
4958
4959                 sh->check_state = head_sh->check_state;
4960                 sh->reconstruct_state = head_sh->reconstruct_state;
4961                 spin_lock_irq(&sh->stripe_lock);
4962                 sh->batch_head = NULL;
4963                 spin_unlock_irq(&sh->stripe_lock);
4964                 for (i = 0; i < sh->disks; i++) {
4965                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
4966                                 do_wakeup = 1;
4967                         sh->dev[i].flags = head_sh->dev[i].flags &
4968                                 (~((1 << R5_WriteError) | (1 << R5_Overlap)));
4969                 }
4970                 if (handle_flags == 0 ||
4971                     sh->state & handle_flags)
4972                         set_bit(STRIPE_HANDLE, &sh->state);
4973                 raid5_release_stripe(sh);
4974         }
4975         spin_lock_irq(&head_sh->stripe_lock);
4976         head_sh->batch_head = NULL;
4977         spin_unlock_irq(&head_sh->stripe_lock);
4978         for (i = 0; i < head_sh->disks; i++)
4979                 if (test_and_clear_bit(R5_Overlap, &head_sh->dev[i].flags))
4980                         do_wakeup = 1;
4981         if (head_sh->state & handle_flags)
4982                 set_bit(STRIPE_HANDLE, &head_sh->state);
4983
4984         if (do_wakeup)
4985                 wake_up(&head_sh->raid_conf->wait_for_overlap);
4986 }
4987
4988 static void handle_stripe(struct stripe_head *sh)
4989 {
4990         struct stripe_head_state s;
4991         struct r5conf *conf = sh->raid_conf;
4992         int i;
4993         int prexor;
4994         int disks = sh->disks;
4995         struct r5dev *pdev, *qdev;
4996
4997         clear_bit(STRIPE_HANDLE, &sh->state);
4998
4999         /*
5000          * handle_stripe should not continue handle the batched stripe, only
5001          * the head of batch list or lone stripe can continue. Otherwise we
5002          * could see break_stripe_batch_list warns about the STRIPE_ACTIVE
5003          * is set for the batched stripe.
5004          */
5005         if (clear_batch_ready(sh))
5006                 return;
5007
5008         if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
5009                 /* already being handled, ensure it gets handled
5010                  * again when current action finishes */
5011                 set_bit(STRIPE_HANDLE, &sh->state);
5012                 return;
5013         }
5014
5015         if (test_and_clear_bit(STRIPE_BATCH_ERR, &sh->state))
5016                 break_stripe_batch_list(sh, 0);
5017
5018         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) && !sh->batch_head) {
5019                 spin_lock(&sh->stripe_lock);
5020                 /*
5021                  * Cannot process 'sync' concurrently with 'discard'.
5022                  * Flush data in r5cache before 'sync'.
5023                  */
5024                 if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) &&
5025                     !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) &&
5026                     !test_bit(STRIPE_DISCARD, &sh->state) &&
5027                     test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
5028                         set_bit(STRIPE_SYNCING, &sh->state);
5029                         clear_bit(STRIPE_INSYNC, &sh->state);
5030                         clear_bit(STRIPE_REPLACED, &sh->state);
5031                 }
5032                 spin_unlock(&sh->stripe_lock);
5033         }
5034         clear_bit(STRIPE_DELAYED, &sh->state);
5035
5036         pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
5037                 "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
5038                (unsigned long long)sh->sector, sh->state,
5039                atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
5040                sh->check_state, sh->reconstruct_state);
5041
5042         analyse_stripe(sh, &s);
5043
5044         if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
5045                 goto finish;
5046
5047         if (s.handle_bad_blocks ||
5048             test_bit(MD_SB_CHANGE_PENDING, &conf->mddev->sb_flags)) {
5049                 set_bit(STRIPE_HANDLE, &sh->state);
5050                 goto finish;
5051         }
5052
5053         if (unlikely(s.blocked_rdev)) {
5054                 if (s.syncing || s.expanding || s.expanded ||
5055                     s.replacing || s.to_write || s.written) {
5056                         set_bit(STRIPE_HANDLE, &sh->state);
5057                         goto finish;
5058                 }
5059                 /* There is nothing for the blocked_rdev to block */
5060                 rdev_dec_pending(s.blocked_rdev, conf->mddev);
5061                 s.blocked_rdev = NULL;
5062         }
5063
5064         if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
5065                 set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
5066                 set_bit(STRIPE_BIOFILL_RUN, &sh->state);
5067         }
5068
5069         pr_debug("locked=%d uptodate=%d to_read=%d"
5070                " to_write=%d failed=%d failed_num=%d,%d\n",
5071                s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
5072                s.failed_num[0], s.failed_num[1]);
5073         /*
5074          * check if the array has lost more than max_degraded devices and,
5075          * if so, some requests might need to be failed.
5076          *
5077          * When journal device failed (log_failed), we will only process
5078          * the stripe if there is data need write to raid disks
5079          */
5080         if (s.failed > conf->max_degraded ||
5081             (s.log_failed && s.injournal == 0)) {
5082                 sh->check_state = 0;
5083                 sh->reconstruct_state = 0;
5084                 break_stripe_batch_list(sh, 0);
5085                 if (s.to_read+s.to_write+s.written)
5086                         handle_failed_stripe(conf, sh, &s, disks);
5087                 if (s.syncing + s.replacing)
5088                         handle_failed_sync(conf, sh, &s);
5089         }
5090
5091         /* Now we check to see if any write operations have recently
5092          * completed
5093          */
5094         prexor = 0;
5095         if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
5096                 prexor = 1;
5097         if (sh->reconstruct_state == reconstruct_state_drain_result ||
5098             sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
5099                 sh->reconstruct_state = reconstruct_state_idle;
5100
5101                 /* All the 'written' buffers and the parity block are ready to
5102                  * be written back to disk
5103                  */
5104                 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
5105                        !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
5106                 BUG_ON(sh->qd_idx >= 0 &&
5107                        !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
5108                        !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
5109                 for (i = disks; i--; ) {
5110                         struct r5dev *dev = &sh->dev[i];
5111                         if (test_bit(R5_LOCKED, &dev->flags) &&
5112                                 (i == sh->pd_idx || i == sh->qd_idx ||
5113                                  dev->written || test_bit(R5_InJournal,
5114                                                           &dev->flags))) {
5115                                 pr_debug("Writing block %d\n", i);
5116                                 set_bit(R5_Wantwrite, &dev->flags);
5117                                 if (prexor)
5118                                         continue;
5119                                 if (s.failed > 1)
5120                                         continue;
5121                                 if (!test_bit(R5_Insync, &dev->flags) ||
5122                                     ((i == sh->pd_idx || i == sh->qd_idx)  &&
5123                                      s.failed == 0))
5124                                         set_bit(STRIPE_INSYNC, &sh->state);
5125                         }
5126                 }
5127                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5128                         s.dec_preread_active = 1;
5129         }
5130
5131         /*
5132          * might be able to return some write requests if the parity blocks
5133          * are safe, or on a failed drive
5134          */
5135         pdev = &sh->dev[sh->pd_idx];
5136         s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
5137                 || (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
5138         qdev = &sh->dev[sh->qd_idx];
5139         s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
5140                 || (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
5141                 || conf->level < 6;
5142
5143         if (s.written &&
5144             (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
5145                              && !test_bit(R5_LOCKED, &pdev->flags)
5146                              && (test_bit(R5_UPTODATE, &pdev->flags) ||
5147                                  test_bit(R5_Discard, &pdev->flags))))) &&
5148             (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
5149                              && !test_bit(R5_LOCKED, &qdev->flags)
5150                              && (test_bit(R5_UPTODATE, &qdev->flags) ||
5151                                  test_bit(R5_Discard, &qdev->flags))))))
5152                 handle_stripe_clean_event(conf, sh, disks);
5153
5154         if (s.just_cached)
5155                 r5c_handle_cached_data_endio(conf, sh, disks);
5156         log_stripe_write_finished(sh);
5157
5158         /* Now we might consider reading some blocks, either to check/generate
5159          * parity, or to satisfy requests
5160          * or to load a block that is being partially written.
5161          */
5162         if (s.to_read || s.non_overwrite
5163             || (s.to_write && s.failed)
5164             || (s.syncing && (s.uptodate + s.compute < disks))
5165             || s.replacing
5166             || s.expanding)
5167                 handle_stripe_fill(sh, &s, disks);
5168
5169         /*
5170          * When the stripe finishes full journal write cycle (write to journal
5171          * and raid disk), this is the clean up procedure so it is ready for
5172          * next operation.
5173          */
5174         r5c_finish_stripe_write_out(conf, sh, &s);
5175
5176         /*
5177          * Now to consider new write requests, cache write back and what else,
5178          * if anything should be read.  We do not handle new writes when:
5179          * 1/ A 'write' operation (copy+xor) is already in flight.
5180          * 2/ A 'check' operation is in flight, as it may clobber the parity
5181          *    block.
5182          * 3/ A r5c cache log write is in flight.
5183          */
5184
5185         if (!sh->reconstruct_state && !sh->check_state && !sh->log_io) {
5186                 if (!r5c_is_writeback(conf->log)) {
5187                         if (s.to_write)
5188                                 handle_stripe_dirtying(conf, sh, &s, disks);
5189                 } else { /* write back cache */
5190                         int ret = 0;
5191
5192                         /* First, try handle writes in caching phase */
5193                         if (s.to_write)
5194                                 ret = r5c_try_caching_write(conf, sh, &s,
5195                                                             disks);
5196                         /*
5197                          * If caching phase failed: ret == -EAGAIN
5198                          *    OR
5199                          * stripe under reclaim: !caching && injournal
5200                          *
5201                          * fall back to handle_stripe_dirtying()
5202                          */
5203                         if (ret == -EAGAIN ||
5204                             /* stripe under reclaim: !caching && injournal */
5205                             (!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
5206                              s.injournal > 0)) {
5207                                 ret = handle_stripe_dirtying(conf, sh, &s,
5208                                                              disks);
5209                                 if (ret == -EAGAIN)
5210                                         goto finish;
5211                         }
5212                 }
5213         }
5214
5215         /* maybe we need to check and possibly fix the parity for this stripe
5216          * Any reads will already have been scheduled, so we just see if enough
5217          * data is available.  The parity check is held off while parity
5218          * dependent operations are in flight.
5219          */
5220         if (sh->check_state ||
5221             (s.syncing && s.locked == 0 &&
5222              !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
5223              !test_bit(STRIPE_INSYNC, &sh->state))) {
5224                 if (conf->level == 6)
5225                         handle_parity_checks6(conf, sh, &s, disks);
5226                 else
5227                         handle_parity_checks5(conf, sh, &s, disks);
5228         }
5229
5230         if ((s.replacing || s.syncing) && s.locked == 0
5231             && !test_bit(STRIPE_COMPUTE_RUN, &sh->state)
5232             && !test_bit(STRIPE_REPLACED, &sh->state)) {
5233                 /* Write out to replacement devices where possible */
5234                 for (i = 0; i < conf->raid_disks; i++)
5235                         if (test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
5236                                 WARN_ON(!test_bit(R5_UPTODATE, &sh->dev[i].flags));
5237                                 set_bit(R5_WantReplace, &sh->dev[i].flags);
5238                                 set_bit(R5_LOCKED, &sh->dev[i].flags);
5239                                 s.locked++;
5240                         }
5241                 if (s.replacing)
5242                         set_bit(STRIPE_INSYNC, &sh->state);
5243                 set_bit(STRIPE_REPLACED, &sh->state);
5244         }
5245         if ((s.syncing || s.replacing) && s.locked == 0 &&
5246             !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
5247             test_bit(STRIPE_INSYNC, &sh->state)) {
5248                 md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), 1);
5249                 clear_bit(STRIPE_SYNCING, &sh->state);
5250                 if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
5251                         wake_up(&conf->wait_for_overlap);
5252         }
5253
5254         /* If the failed drives are just a ReadError, then we might need
5255          * to progress the repair/check process
5256          */
5257         if (s.failed <= conf->max_degraded && !conf->mddev->ro)
5258                 for (i = 0; i < s.failed; i++) {
5259                         struct r5dev *dev = &sh->dev[s.failed_num[i]];
5260                         if (test_bit(R5_ReadError, &dev->flags)
5261                             && !test_bit(R5_LOCKED, &dev->flags)
5262                             && test_bit(R5_UPTODATE, &dev->flags)
5263                                 ) {
5264                                 if (!test_bit(R5_ReWrite, &dev->flags)) {
5265                                         set_bit(R5_Wantwrite, &dev->flags);
5266                                         set_bit(R5_ReWrite, &dev->flags);
5267                                 } else
5268                                         /* let's read it back */
5269                                         set_bit(R5_Wantread, &dev->flags);
5270                                 set_bit(R5_LOCKED, &dev->flags);
5271                                 s.locked++;
5272                         }
5273                 }
5274
5275         /* Finish reconstruct operations initiated by the expansion process */
5276         if (sh->reconstruct_state == reconstruct_state_result) {
5277                 struct stripe_head *sh_src
5278                         = raid5_get_active_stripe(conf, NULL, sh->sector,
5279                                         R5_GAS_PREVIOUS | R5_GAS_NOBLOCK |
5280                                         R5_GAS_NOQUIESCE);
5281                 if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
5282                         /* sh cannot be written until sh_src has been read.
5283                          * so arrange for sh to be delayed a little
5284                          */
5285                         set_bit(STRIPE_DELAYED, &sh->state);
5286                         set_bit(STRIPE_HANDLE, &sh->state);
5287                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
5288                                               &sh_src->state))
5289                                 atomic_inc(&conf->preread_active_stripes);
5290                         raid5_release_stripe(sh_src);
5291                         goto finish;
5292                 }
5293                 if (sh_src)
5294                         raid5_release_stripe(sh_src);
5295
5296                 sh->reconstruct_state = reconstruct_state_idle;
5297                 clear_bit(STRIPE_EXPANDING, &sh->state);
5298                 for (i = conf->raid_disks; i--; ) {
5299                         set_bit(R5_Wantwrite, &sh->dev[i].flags);
5300                         set_bit(R5_LOCKED, &sh->dev[i].flags);
5301                         s.locked++;
5302                 }
5303         }
5304
5305         if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
5306             !sh->reconstruct_state) {
5307                 /* Need to write out all blocks after computing parity */
5308                 sh->disks = conf->raid_disks;
5309                 stripe_set_idx(sh->sector, conf, 0, sh);
5310                 schedule_reconstruction(sh, &s, 1, 1);
5311         } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
5312                 clear_bit(STRIPE_EXPAND_READY, &sh->state);
5313                 atomic_dec(&conf->reshape_stripes);
5314                 wake_up(&conf->wait_for_overlap);
5315                 md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), 1);
5316         }
5317
5318         if (s.expanding && s.locked == 0 &&
5319             !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
5320                 handle_stripe_expansion(conf, sh);
5321
5322 finish:
5323         /* wait for this device to become unblocked */
5324         if (unlikely(s.blocked_rdev)) {
5325                 if (conf->mddev->external)
5326                         md_wait_for_blocked_rdev(s.blocked_rdev,
5327                                                  conf->mddev);
5328                 else
5329                         /* Internal metadata will immediately
5330                          * be written by raid5d, so we don't
5331                          * need to wait here.
5332                          */
5333                         rdev_dec_pending(s.blocked_rdev,
5334                                          conf->mddev);
5335         }
5336
5337         if (s.handle_bad_blocks)
5338                 for (i = disks; i--; ) {
5339                         struct md_rdev *rdev;
5340                         struct r5dev *dev = &sh->dev[i];
5341                         if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
5342                                 /* We own a safe reference to the rdev */
5343                                 rdev = rdev_pend_deref(conf->disks[i].rdev);
5344                                 if (!rdev_set_badblocks(rdev, sh->sector,
5345                                                         RAID5_STRIPE_SECTORS(conf), 0))
5346                                         md_error(conf->mddev, rdev);
5347                                 rdev_dec_pending(rdev, conf->mddev);
5348                         }
5349                         if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
5350                                 rdev = rdev_pend_deref(conf->disks[i].rdev);
5351                                 rdev_clear_badblocks(rdev, sh->sector,
5352                                                      RAID5_STRIPE_SECTORS(conf), 0);
5353                                 rdev_dec_pending(rdev, conf->mddev);
5354                         }
5355                         if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
5356                                 rdev = rdev_pend_deref(conf->disks[i].replacement);
5357                                 if (!rdev)
5358                                         /* rdev have been moved down */
5359                                         rdev = rdev_pend_deref(conf->disks[i].rdev);
5360                                 rdev_clear_badblocks(rdev, sh->sector,
5361                                                      RAID5_STRIPE_SECTORS(conf), 0);
5362                                 rdev_dec_pending(rdev, conf->mddev);
5363                         }
5364                 }
5365
5366         if (s.ops_request)
5367                 raid_run_ops(sh, s.ops_request);
5368
5369         ops_run_io(sh, &s);
5370
5371         if (s.dec_preread_active) {
5372                 /* We delay this until after ops_run_io so that if make_request
5373                  * is waiting on a flush, it won't continue until the writes
5374                  * have actually been submitted.
5375                  */
5376                 atomic_dec(&conf->preread_active_stripes);
5377                 if (atomic_read(&conf->preread_active_stripes) <
5378                     IO_THRESHOLD)
5379                         md_wakeup_thread(conf->mddev->thread);
5380         }
5381
5382         clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
5383 }
5384
5385 static void raid5_activate_delayed(struct r5conf *conf)
5386         __must_hold(&conf->device_lock)
5387 {
5388         if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
5389                 while (!list_empty(&conf->delayed_list)) {
5390                         struct list_head *l = conf->delayed_list.next;
5391                         struct stripe_head *sh;
5392                         sh = list_entry(l, struct stripe_head, lru);
5393                         list_del_init(l);
5394                         clear_bit(STRIPE_DELAYED, &sh->state);
5395                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5396                                 atomic_inc(&conf->preread_active_stripes);
5397                         list_add_tail(&sh->lru, &conf->hold_list);
5398                         raid5_wakeup_stripe_thread(sh);
5399                 }
5400         }
5401 }
5402
5403 static void activate_bit_delay(struct r5conf *conf,
5404                 struct list_head *temp_inactive_list)
5405         __must_hold(&conf->device_lock)
5406 {
5407         struct list_head head;
5408         list_add(&head, &conf->bitmap_list);
5409         list_del_init(&conf->bitmap_list);
5410         while (!list_empty(&head)) {
5411                 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
5412                 int hash;
5413                 list_del_init(&sh->lru);
5414                 atomic_inc(&sh->count);
5415                 hash = sh->hash_lock_index;
5416                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
5417         }
5418 }
5419
5420 static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
5421 {
5422         struct r5conf *conf = mddev->private;
5423         sector_t sector = bio->bi_iter.bi_sector;
5424         unsigned int chunk_sectors;
5425         unsigned int bio_sectors = bio_sectors(bio);
5426
5427         chunk_sectors = min(conf->chunk_sectors, conf->prev_chunk_sectors);
5428         return  chunk_sectors >=
5429                 ((sector & (chunk_sectors - 1)) + bio_sectors);
5430 }
5431
5432 /*
5433  *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
5434  *  later sampled by raid5d.
5435  */
5436 static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
5437 {
5438         unsigned long flags;
5439
5440         spin_lock_irqsave(&conf->device_lock, flags);
5441
5442         bi->bi_next = conf->retry_read_aligned_list;
5443         conf->retry_read_aligned_list = bi;
5444
5445         spin_unlock_irqrestore(&conf->device_lock, flags);
5446         md_wakeup_thread(conf->mddev->thread);
5447 }
5448
5449 static struct bio *remove_bio_from_retry(struct r5conf *conf,
5450                                          unsigned int *offset)
5451 {
5452         struct bio *bi;
5453
5454         bi = conf->retry_read_aligned;
5455         if (bi) {
5456                 *offset = conf->retry_read_offset;
5457                 conf->retry_read_aligned = NULL;
5458                 return bi;
5459         }
5460         bi = conf->retry_read_aligned_list;
5461         if(bi) {
5462                 conf->retry_read_aligned_list = bi->bi_next;
5463                 bi->bi_next = NULL;
5464                 *offset = 0;
5465         }
5466
5467         return bi;
5468 }
5469
5470 /*
5471  *  The "raid5_align_endio" should check if the read succeeded and if it
5472  *  did, call bio_endio on the original bio (having bio_put the new bio
5473  *  first).
5474  *  If the read failed..
5475  */
5476 static void raid5_align_endio(struct bio *bi)
5477 {
5478         struct bio *raid_bi = bi->bi_private;
5479         struct md_rdev *rdev = (void *)raid_bi->bi_next;
5480         struct mddev *mddev = rdev->mddev;
5481         struct r5conf *conf = mddev->private;
5482         blk_status_t error = bi->bi_status;
5483
5484         bio_put(bi);
5485         raid_bi->bi_next = NULL;
5486         rdev_dec_pending(rdev, conf->mddev);
5487
5488         if (!error) {
5489                 bio_endio(raid_bi);
5490                 if (atomic_dec_and_test(&conf->active_aligned_reads))
5491                         wake_up(&conf->wait_for_quiescent);
5492                 return;
5493         }
5494
5495         pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
5496
5497         add_bio_to_retry(raid_bi, conf);
5498 }
5499
5500 static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
5501 {
5502         struct r5conf *conf = mddev->private;
5503         struct bio *align_bio;
5504         struct md_rdev *rdev;
5505         sector_t sector, end_sector, first_bad;
5506         int bad_sectors, dd_idx;
5507         bool did_inc;
5508
5509         if (!in_chunk_boundary(mddev, raid_bio)) {
5510                 pr_debug("%s: non aligned\n", __func__);
5511                 return 0;
5512         }
5513
5514         sector = raid5_compute_sector(conf, raid_bio->bi_iter.bi_sector, 0,
5515                                       &dd_idx, NULL);
5516         end_sector = sector + bio_sectors(raid_bio);
5517
5518         rcu_read_lock();
5519         if (r5c_big_stripe_cached(conf, sector))
5520                 goto out_rcu_unlock;
5521
5522         rdev = rcu_dereference(conf->disks[dd_idx].replacement);
5523         if (!rdev || test_bit(Faulty, &rdev->flags) ||
5524             rdev->recovery_offset < end_sector) {
5525                 rdev = rcu_dereference(conf->disks[dd_idx].rdev);
5526                 if (!rdev)
5527                         goto out_rcu_unlock;
5528                 if (test_bit(Faulty, &rdev->flags) ||
5529                     !(test_bit(In_sync, &rdev->flags) ||
5530                       rdev->recovery_offset >= end_sector))
5531                         goto out_rcu_unlock;
5532         }
5533
5534         atomic_inc(&rdev->nr_pending);
5535         rcu_read_unlock();
5536
5537         if (is_badblock(rdev, sector, bio_sectors(raid_bio), &first_bad,
5538                         &bad_sectors)) {
5539                 rdev_dec_pending(rdev, mddev);
5540                 return 0;
5541         }
5542
5543         md_account_bio(mddev, &raid_bio);
5544         raid_bio->bi_next = (void *)rdev;
5545
5546         align_bio = bio_alloc_clone(rdev->bdev, raid_bio, GFP_NOIO,
5547                                     &mddev->bio_set);
5548         align_bio->bi_end_io = raid5_align_endio;
5549         align_bio->bi_private = raid_bio;
5550         align_bio->bi_iter.bi_sector = sector;
5551
5552         /* No reshape active, so we can trust rdev->data_offset */
5553         align_bio->bi_iter.bi_sector += rdev->data_offset;
5554
5555         did_inc = false;
5556         if (conf->quiesce == 0) {
5557                 atomic_inc(&conf->active_aligned_reads);
5558                 did_inc = true;
5559         }
5560         /* need a memory barrier to detect the race with raid5_quiesce() */
5561         if (!did_inc || smp_load_acquire(&conf->quiesce) != 0) {
5562                 /* quiesce is in progress, so we need to undo io activation and wait
5563                  * for it to finish
5564                  */
5565                 if (did_inc && atomic_dec_and_test(&conf->active_aligned_reads))
5566                         wake_up(&conf->wait_for_quiescent);
5567                 spin_lock_irq(&conf->device_lock);
5568                 wait_event_lock_irq(conf->wait_for_quiescent, conf->quiesce == 0,
5569                                     conf->device_lock);
5570                 atomic_inc(&conf->active_aligned_reads);
5571                 spin_unlock_irq(&conf->device_lock);
5572         }
5573
5574         if (mddev->gendisk)
5575                 trace_block_bio_remap(align_bio, disk_devt(mddev->gendisk),
5576                                       raid_bio->bi_iter.bi_sector);
5577         submit_bio_noacct(align_bio);
5578         return 1;
5579
5580 out_rcu_unlock:
5581         rcu_read_unlock();
5582         return 0;
5583 }
5584
5585 static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
5586 {
5587         struct bio *split;
5588         sector_t sector = raid_bio->bi_iter.bi_sector;
5589         unsigned chunk_sects = mddev->chunk_sectors;
5590         unsigned sectors = chunk_sects - (sector & (chunk_sects-1));
5591
5592         if (sectors < bio_sectors(raid_bio)) {
5593                 struct r5conf *conf = mddev->private;
5594                 split = bio_split(raid_bio, sectors, GFP_NOIO, &conf->bio_split);
5595                 bio_chain(split, raid_bio);
5596                 submit_bio_noacct(raid_bio);
5597                 raid_bio = split;
5598         }
5599
5600         if (!raid5_read_one_chunk(mddev, raid_bio))
5601                 return raid_bio;
5602
5603         return NULL;
5604 }
5605
5606 /* __get_priority_stripe - get the next stripe to process
5607  *
5608  * Full stripe writes are allowed to pass preread active stripes up until
5609  * the bypass_threshold is exceeded.  In general the bypass_count
5610  * increments when the handle_list is handled before the hold_list; however, it
5611  * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
5612  * stripe with in flight i/o.  The bypass_count will be reset when the
5613  * head of the hold_list has changed, i.e. the head was promoted to the
5614  * handle_list.
5615  */
5616 static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group)
5617         __must_hold(&conf->device_lock)
5618 {
5619         struct stripe_head *sh, *tmp;
5620         struct list_head *handle_list = NULL;
5621         struct r5worker_group *wg;
5622         bool second_try = !r5c_is_writeback(conf->log) &&
5623                 !r5l_log_disk_error(conf);
5624         bool try_loprio = test_bit(R5C_LOG_TIGHT, &conf->cache_state) ||
5625                 r5l_log_disk_error(conf);
5626
5627 again:
5628         wg = NULL;
5629         sh = NULL;
5630         if (conf->worker_cnt_per_group == 0) {
5631                 handle_list = try_loprio ? &conf->loprio_list :
5632                                         &conf->handle_list;
5633         } else if (group != ANY_GROUP) {
5634                 handle_list = try_loprio ? &conf->worker_groups[group].loprio_list :
5635                                 &conf->worker_groups[group].handle_list;
5636                 wg = &conf->worker_groups[group];
5637         } else {
5638                 int i;
5639                 for (i = 0; i < conf->group_cnt; i++) {
5640                         handle_list = try_loprio ? &conf->worker_groups[i].loprio_list :
5641                                 &conf->worker_groups[i].handle_list;
5642                         wg = &conf->worker_groups[i];
5643                         if (!list_empty(handle_list))
5644                                 break;
5645                 }
5646         }
5647
5648         pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
5649                   __func__,
5650                   list_empty(handle_list) ? "empty" : "busy",
5651                   list_empty(&conf->hold_list) ? "empty" : "busy",
5652                   atomic_read(&conf->pending_full_writes), conf->bypass_count);
5653
5654         if (!list_empty(handle_list)) {
5655                 sh = list_entry(handle_list->next, typeof(*sh), lru);
5656
5657                 if (list_empty(&conf->hold_list))
5658                         conf->bypass_count = 0;
5659                 else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
5660                         if (conf->hold_list.next == conf->last_hold)
5661                                 conf->bypass_count++;
5662                         else {
5663                                 conf->last_hold = conf->hold_list.next;
5664                                 conf->bypass_count -= conf->bypass_threshold;
5665                                 if (conf->bypass_count < 0)
5666                                         conf->bypass_count = 0;
5667                         }
5668                 }
5669         } else if (!list_empty(&conf->hold_list) &&
5670                    ((conf->bypass_threshold &&
5671                      conf->bypass_count > conf->bypass_threshold) ||
5672                     atomic_read(&conf->pending_full_writes) == 0)) {
5673
5674                 list_for_each_entry(tmp, &conf->hold_list,  lru) {
5675                         if (conf->worker_cnt_per_group == 0 ||
5676                             group == ANY_GROUP ||
5677                             !cpu_online(tmp->cpu) ||
5678                             cpu_to_group(tmp->cpu) == group) {
5679                                 sh = tmp;
5680                                 break;
5681                         }
5682                 }
5683
5684                 if (sh) {
5685                         conf->bypass_count -= conf->bypass_threshold;
5686                         if (conf->bypass_count < 0)
5687                                 conf->bypass_count = 0;
5688                 }
5689                 wg = NULL;
5690         }
5691
5692         if (!sh) {
5693                 if (second_try)
5694                         return NULL;
5695                 second_try = true;
5696                 try_loprio = !try_loprio;
5697                 goto again;
5698         }
5699
5700         if (wg) {
5701                 wg->stripes_cnt--;
5702                 sh->group = NULL;
5703         }
5704         list_del_init(&sh->lru);
5705         BUG_ON(atomic_inc_return(&sh->count) != 1);
5706         return sh;
5707 }
5708
5709 struct raid5_plug_cb {
5710         struct blk_plug_cb      cb;
5711         struct list_head        list;
5712         struct list_head        temp_inactive_list[NR_STRIPE_HASH_LOCKS];
5713 };
5714
5715 static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
5716 {
5717         struct raid5_plug_cb *cb = container_of(
5718                 blk_cb, struct raid5_plug_cb, cb);
5719         struct stripe_head *sh;
5720         struct mddev *mddev = cb->cb.data;
5721         struct r5conf *conf = mddev->private;
5722         int cnt = 0;
5723         int hash;
5724
5725         if (cb->list.next && !list_empty(&cb->list)) {
5726                 spin_lock_irq(&conf->device_lock);
5727                 while (!list_empty(&cb->list)) {
5728                         sh = list_first_entry(&cb->list, struct stripe_head, lru);
5729                         list_del_init(&sh->lru);
5730                         /*
5731                          * avoid race release_stripe_plug() sees
5732                          * STRIPE_ON_UNPLUG_LIST clear but the stripe
5733                          * is still in our list
5734                          */
5735                         smp_mb__before_atomic();
5736                         clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
5737                         /*
5738                          * STRIPE_ON_RELEASE_LIST could be set here. In that
5739                          * case, the count is always > 1 here
5740                          */
5741                         hash = sh->hash_lock_index;
5742                         __release_stripe(conf, sh, &cb->temp_inactive_list[hash]);
5743                         cnt++;
5744                 }
5745                 spin_unlock_irq(&conf->device_lock);
5746         }
5747         release_inactive_stripe_list(conf, cb->temp_inactive_list,
5748                                      NR_STRIPE_HASH_LOCKS);
5749         if (mddev->queue)
5750                 trace_block_unplug(mddev->queue, cnt, !from_schedule);
5751         kfree(cb);
5752 }
5753
5754 static void release_stripe_plug(struct mddev *mddev,
5755                                 struct stripe_head *sh)
5756 {
5757         struct blk_plug_cb *blk_cb = blk_check_plugged(
5758                 raid5_unplug, mddev,
5759                 sizeof(struct raid5_plug_cb));
5760         struct raid5_plug_cb *cb;
5761
5762         if (!blk_cb) {
5763                 raid5_release_stripe(sh);
5764                 return;
5765         }
5766
5767         cb = container_of(blk_cb, struct raid5_plug_cb, cb);
5768
5769         if (cb->list.next == NULL) {
5770                 int i;
5771                 INIT_LIST_HEAD(&cb->list);
5772                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
5773                         INIT_LIST_HEAD(cb->temp_inactive_list + i);
5774         }
5775
5776         if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
5777                 list_add_tail(&sh->lru, &cb->list);
5778         else
5779                 raid5_release_stripe(sh);
5780 }
5781
5782 static void make_discard_request(struct mddev *mddev, struct bio *bi)
5783 {
5784         struct r5conf *conf = mddev->private;
5785         sector_t logical_sector, last_sector;
5786         struct stripe_head *sh;
5787         int stripe_sectors;
5788
5789         /* We need to handle this when io_uring supports discard/trim */
5790         if (WARN_ON_ONCE(bi->bi_opf & REQ_NOWAIT))
5791                 return;
5792
5793         if (mddev->reshape_position != MaxSector)
5794                 /* Skip discard while reshape is happening */
5795                 return;
5796
5797         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
5798         last_sector = bio_end_sector(bi);
5799
5800         bi->bi_next = NULL;
5801
5802         stripe_sectors = conf->chunk_sectors *
5803                 (conf->raid_disks - conf->max_degraded);
5804         logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
5805                                                stripe_sectors);
5806         sector_div(last_sector, stripe_sectors);
5807
5808         logical_sector *= conf->chunk_sectors;
5809         last_sector *= conf->chunk_sectors;
5810
5811         for (; logical_sector < last_sector;
5812              logical_sector += RAID5_STRIPE_SECTORS(conf)) {
5813                 DEFINE_WAIT(w);
5814                 int d;
5815         again:
5816                 sh = raid5_get_active_stripe(conf, NULL, logical_sector, 0);
5817                 prepare_to_wait(&conf->wait_for_overlap, &w,
5818                                 TASK_UNINTERRUPTIBLE);
5819                 set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5820                 if (test_bit(STRIPE_SYNCING, &sh->state)) {
5821                         raid5_release_stripe(sh);
5822                         schedule();
5823                         goto again;
5824                 }
5825                 clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5826                 spin_lock_irq(&sh->stripe_lock);
5827                 for (d = 0; d < conf->raid_disks; d++) {
5828                         if (d == sh->pd_idx || d == sh->qd_idx)
5829                                 continue;
5830                         if (sh->dev[d].towrite || sh->dev[d].toread) {
5831                                 set_bit(R5_Overlap, &sh->dev[d].flags);
5832                                 spin_unlock_irq(&sh->stripe_lock);
5833                                 raid5_release_stripe(sh);
5834                                 schedule();
5835                                 goto again;
5836                         }
5837                 }
5838                 set_bit(STRIPE_DISCARD, &sh->state);
5839                 finish_wait(&conf->wait_for_overlap, &w);
5840                 sh->overwrite_disks = 0;
5841                 for (d = 0; d < conf->raid_disks; d++) {
5842                         if (d == sh->pd_idx || d == sh->qd_idx)
5843                                 continue;
5844                         sh->dev[d].towrite = bi;
5845                         set_bit(R5_OVERWRITE, &sh->dev[d].flags);
5846                         bio_inc_remaining(bi);
5847                         md_write_inc(mddev, bi);
5848                         sh->overwrite_disks++;
5849                 }
5850                 spin_unlock_irq(&sh->stripe_lock);
5851                 if (conf->mddev->bitmap) {
5852                         for (d = 0;
5853                              d < conf->raid_disks - conf->max_degraded;
5854                              d++)
5855                                 md_bitmap_startwrite(mddev->bitmap,
5856                                                      sh->sector,
5857                                                      RAID5_STRIPE_SECTORS(conf),
5858                                                      0);
5859                         sh->bm_seq = conf->seq_flush + 1;
5860                         set_bit(STRIPE_BIT_DELAY, &sh->state);
5861                 }
5862
5863                 set_bit(STRIPE_HANDLE, &sh->state);
5864                 clear_bit(STRIPE_DELAYED, &sh->state);
5865                 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5866                         atomic_inc(&conf->preread_active_stripes);
5867                 release_stripe_plug(mddev, sh);
5868         }
5869
5870         bio_endio(bi);
5871 }
5872
5873 static bool ahead_of_reshape(struct mddev *mddev, sector_t sector,
5874                              sector_t reshape_sector)
5875 {
5876         return mddev->reshape_backwards ? sector < reshape_sector :
5877                                           sector >= reshape_sector;
5878 }
5879
5880 static bool range_ahead_of_reshape(struct mddev *mddev, sector_t min,
5881                                    sector_t max, sector_t reshape_sector)
5882 {
5883         return mddev->reshape_backwards ? max < reshape_sector :
5884                                           min >= reshape_sector;
5885 }
5886
5887 static bool stripe_ahead_of_reshape(struct mddev *mddev, struct r5conf *conf,
5888                                     struct stripe_head *sh)
5889 {
5890         sector_t max_sector = 0, min_sector = MaxSector;
5891         bool ret = false;
5892         int dd_idx;
5893
5894         for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) {
5895                 if (dd_idx == sh->pd_idx)
5896                         continue;
5897
5898                 min_sector = min(min_sector, sh->dev[dd_idx].sector);
5899                 max_sector = min(max_sector, sh->dev[dd_idx].sector);
5900         }
5901
5902         spin_lock_irq(&conf->device_lock);
5903
5904         if (!range_ahead_of_reshape(mddev, min_sector, max_sector,
5905                                      conf->reshape_progress))
5906                 /* mismatch, need to try again */
5907                 ret = true;
5908
5909         spin_unlock_irq(&conf->device_lock);
5910
5911         return ret;
5912 }
5913
5914 static int add_all_stripe_bios(struct r5conf *conf,
5915                 struct stripe_request_ctx *ctx, struct stripe_head *sh,
5916                 struct bio *bi, int forwrite, int previous)
5917 {
5918         int dd_idx;
5919         int ret = 1;
5920
5921         spin_lock_irq(&sh->stripe_lock);
5922
5923         for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) {
5924                 struct r5dev *dev = &sh->dev[dd_idx];
5925
5926                 if (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
5927                         continue;
5928
5929                 if (dev->sector < ctx->first_sector ||
5930                     dev->sector >= ctx->last_sector)
5931                         continue;
5932
5933                 if (stripe_bio_overlaps(sh, bi, dd_idx, forwrite)) {
5934                         set_bit(R5_Overlap, &dev->flags);
5935                         ret = 0;
5936                         continue;
5937                 }
5938         }
5939
5940         if (!ret)
5941                 goto out;
5942
5943         for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) {
5944                 struct r5dev *dev = &sh->dev[dd_idx];
5945
5946                 if (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
5947                         continue;
5948
5949                 if (dev->sector < ctx->first_sector ||
5950                     dev->sector >= ctx->last_sector)
5951                         continue;
5952
5953                 __add_stripe_bio(sh, bi, dd_idx, forwrite, previous);
5954                 clear_bit((dev->sector - ctx->first_sector) >>
5955                           RAID5_STRIPE_SHIFT(conf), ctx->sectors_to_do);
5956         }
5957
5958 out:
5959         spin_unlock_irq(&sh->stripe_lock);
5960         return ret;
5961 }
5962
5963 static bool reshape_inprogress(struct mddev *mddev)
5964 {
5965         return test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
5966                test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
5967                !test_bit(MD_RECOVERY_DONE, &mddev->recovery) &&
5968                !test_bit(MD_RECOVERY_INTR, &mddev->recovery);
5969 }
5970
5971 static bool reshape_disabled(struct mddev *mddev)
5972 {
5973         return is_md_suspended(mddev) || !md_is_rdwr(mddev);
5974 }
5975
5976 static enum stripe_result make_stripe_request(struct mddev *mddev,
5977                 struct r5conf *conf, struct stripe_request_ctx *ctx,
5978                 sector_t logical_sector, struct bio *bi)
5979 {
5980         const int rw = bio_data_dir(bi);
5981         enum stripe_result ret;
5982         struct stripe_head *sh;
5983         sector_t new_sector;
5984         int previous = 0, flags = 0;
5985         int seq, dd_idx;
5986
5987         seq = read_seqcount_begin(&conf->gen_lock);
5988
5989         if (unlikely(conf->reshape_progress != MaxSector)) {
5990                 /*
5991                  * Spinlock is needed as reshape_progress may be
5992                  * 64bit on a 32bit platform, and so it might be
5993                  * possible to see a half-updated value
5994                  * Of course reshape_progress could change after
5995                  * the lock is dropped, so once we get a reference
5996                  * to the stripe that we think it is, we will have
5997                  * to check again.
5998                  */
5999                 spin_lock_irq(&conf->device_lock);
6000                 if (ahead_of_reshape(mddev, logical_sector,
6001                                      conf->reshape_progress)) {
6002                         previous = 1;
6003                 } else {
6004                         if (ahead_of_reshape(mddev, logical_sector,
6005                                              conf->reshape_safe)) {
6006                                 spin_unlock_irq(&conf->device_lock);
6007                                 ret = STRIPE_SCHEDULE_AND_RETRY;
6008                                 goto out;
6009                         }
6010                 }
6011                 spin_unlock_irq(&conf->device_lock);
6012         }
6013
6014         new_sector = raid5_compute_sector(conf, logical_sector, previous,
6015                                           &dd_idx, NULL);
6016         pr_debug("raid456: %s, sector %llu logical %llu\n", __func__,
6017                  new_sector, logical_sector);
6018
6019         if (previous)
6020                 flags |= R5_GAS_PREVIOUS;
6021         if (bi->bi_opf & REQ_RAHEAD)
6022                 flags |= R5_GAS_NOBLOCK;
6023         sh = raid5_get_active_stripe(conf, ctx, new_sector, flags);
6024         if (unlikely(!sh)) {
6025                 /* cannot get stripe, just give-up */
6026                 bi->bi_status = BLK_STS_IOERR;
6027                 return STRIPE_FAIL;
6028         }
6029
6030         if (unlikely(previous) &&
6031             stripe_ahead_of_reshape(mddev, conf, sh)) {
6032                 /*
6033                  * Expansion moved on while waiting for a stripe.
6034                  * Expansion could still move past after this
6035                  * test, but as we are holding a reference to
6036                  * 'sh', we know that if that happens,
6037                  *  STRIPE_EXPANDING will get set and the expansion
6038                  * won't proceed until we finish with the stripe.
6039                  */
6040                 ret = STRIPE_SCHEDULE_AND_RETRY;
6041                 goto out_release;
6042         }
6043
6044         if (read_seqcount_retry(&conf->gen_lock, seq)) {
6045                 /* Might have got the wrong stripe_head by accident */
6046                 ret = STRIPE_RETRY;
6047                 goto out_release;
6048         }
6049
6050         if (test_bit(STRIPE_EXPANDING, &sh->state) ||
6051             !add_all_stripe_bios(conf, ctx, sh, bi, rw, previous)) {
6052                 /*
6053                  * Stripe is busy expanding or add failed due to
6054                  * overlap. Flush everything and wait a while.
6055                  */
6056                 md_wakeup_thread(mddev->thread);
6057                 ret = STRIPE_SCHEDULE_AND_RETRY;
6058                 goto out_release;
6059         }
6060
6061         if (stripe_can_batch(sh)) {
6062                 stripe_add_to_batch_list(conf, sh, ctx->batch_last);
6063                 if (ctx->batch_last)
6064                         raid5_release_stripe(ctx->batch_last);
6065                 atomic_inc(&sh->count);
6066                 ctx->batch_last = sh;
6067         }
6068
6069         if (ctx->do_flush) {
6070                 set_bit(STRIPE_R5C_PREFLUSH, &sh->state);
6071                 /* we only need flush for one stripe */
6072                 ctx->do_flush = false;
6073         }
6074
6075         set_bit(STRIPE_HANDLE, &sh->state);
6076         clear_bit(STRIPE_DELAYED, &sh->state);
6077         if ((!sh->batch_head || sh == sh->batch_head) &&
6078             (bi->bi_opf & REQ_SYNC) &&
6079             !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
6080                 atomic_inc(&conf->preread_active_stripes);
6081
6082         release_stripe_plug(mddev, sh);
6083         return STRIPE_SUCCESS;
6084
6085 out_release:
6086         raid5_release_stripe(sh);
6087 out:
6088         if (ret == STRIPE_SCHEDULE_AND_RETRY && !reshape_inprogress(mddev) &&
6089             reshape_disabled(mddev)) {
6090                 bi->bi_status = BLK_STS_IOERR;
6091                 ret = STRIPE_FAIL;
6092                 pr_err("md/raid456:%s: io failed across reshape position while reshape can't make progress.\n",
6093                        mdname(mddev));
6094         }
6095
6096         return ret;
6097 }
6098
6099 /*
6100  * If the bio covers multiple data disks, find sector within the bio that has
6101  * the lowest chunk offset in the first chunk.
6102  */
6103 static sector_t raid5_bio_lowest_chunk_sector(struct r5conf *conf,
6104                                               struct bio *bi)
6105 {
6106         int sectors_per_chunk = conf->chunk_sectors;
6107         int raid_disks = conf->raid_disks;
6108         int dd_idx;
6109         struct stripe_head sh;
6110         unsigned int chunk_offset;
6111         sector_t r_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
6112         sector_t sector;
6113
6114         /* We pass in fake stripe_head to get back parity disk numbers */
6115         sector = raid5_compute_sector(conf, r_sector, 0, &dd_idx, &sh);
6116         chunk_offset = sector_div(sector, sectors_per_chunk);
6117         if (sectors_per_chunk - chunk_offset >= bio_sectors(bi))
6118                 return r_sector;
6119         /*
6120          * Bio crosses to the next data disk. Check whether it's in the same
6121          * chunk.
6122          */
6123         dd_idx++;
6124         while (dd_idx == sh.pd_idx || dd_idx == sh.qd_idx)
6125                 dd_idx++;
6126         if (dd_idx >= raid_disks)
6127                 return r_sector;
6128         return r_sector + sectors_per_chunk - chunk_offset;
6129 }
6130
6131 static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
6132 {
6133         DEFINE_WAIT_FUNC(wait, woken_wake_function);
6134         struct r5conf *conf = mddev->private;
6135         sector_t logical_sector;
6136         struct stripe_request_ctx ctx = {};
6137         const int rw = bio_data_dir(bi);
6138         enum stripe_result res;
6139         int s, stripe_cnt;
6140
6141         if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
6142                 int ret = log_handle_flush_request(conf, bi);
6143
6144                 if (ret == 0)
6145                         return true;
6146                 if (ret == -ENODEV) {
6147                         if (md_flush_request(mddev, bi))
6148                                 return true;
6149                 }
6150                 /* ret == -EAGAIN, fallback */
6151                 /*
6152                  * if r5l_handle_flush_request() didn't clear REQ_PREFLUSH,
6153                  * we need to flush journal device
6154                  */
6155                 ctx.do_flush = bi->bi_opf & REQ_PREFLUSH;
6156         }
6157
6158         if (!md_write_start(mddev, bi))
6159                 return false;
6160         /*
6161          * If array is degraded, better not do chunk aligned read because
6162          * later we might have to read it again in order to reconstruct
6163          * data on failed drives.
6164          */
6165         if (rw == READ && mddev->degraded == 0 &&
6166             mddev->reshape_position == MaxSector) {
6167                 bi = chunk_aligned_read(mddev, bi);
6168                 if (!bi)
6169                         return true;
6170         }
6171
6172         if (unlikely(bio_op(bi) == REQ_OP_DISCARD)) {
6173                 make_discard_request(mddev, bi);
6174                 md_write_end(mddev);
6175                 return true;
6176         }
6177
6178         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
6179         ctx.first_sector = logical_sector;
6180         ctx.last_sector = bio_end_sector(bi);
6181         bi->bi_next = NULL;
6182
6183         stripe_cnt = DIV_ROUND_UP_SECTOR_T(ctx.last_sector - logical_sector,
6184                                            RAID5_STRIPE_SECTORS(conf));
6185         bitmap_set(ctx.sectors_to_do, 0, stripe_cnt);
6186
6187         pr_debug("raid456: %s, logical %llu to %llu\n", __func__,
6188                  bi->bi_iter.bi_sector, ctx.last_sector);
6189
6190         /* Bail out if conflicts with reshape and REQ_NOWAIT is set */
6191         if ((bi->bi_opf & REQ_NOWAIT) &&
6192             (conf->reshape_progress != MaxSector) &&
6193             !ahead_of_reshape(mddev, logical_sector, conf->reshape_progress) &&
6194             ahead_of_reshape(mddev, logical_sector, conf->reshape_safe)) {
6195                 bio_wouldblock_error(bi);
6196                 if (rw == WRITE)
6197                         md_write_end(mddev);
6198                 return true;
6199         }
6200         md_account_bio(mddev, &bi);
6201
6202         /*
6203          * Lets start with the stripe with the lowest chunk offset in the first
6204          * chunk. That has the best chances of creating IOs adjacent to
6205          * previous IOs in case of sequential IO and thus creates the most
6206          * sequential IO pattern. We don't bother with the optimization when
6207          * reshaping as the performance benefit is not worth the complexity.
6208          */
6209         if (likely(conf->reshape_progress == MaxSector))
6210                 logical_sector = raid5_bio_lowest_chunk_sector(conf, bi);
6211         s = (logical_sector - ctx.first_sector) >> RAID5_STRIPE_SHIFT(conf);
6212
6213         add_wait_queue(&conf->wait_for_overlap, &wait);
6214         while (1) {
6215                 res = make_stripe_request(mddev, conf, &ctx, logical_sector,
6216                                           bi);
6217                 if (res == STRIPE_FAIL)
6218                         break;
6219
6220                 if (res == STRIPE_RETRY)
6221                         continue;
6222
6223                 if (res == STRIPE_SCHEDULE_AND_RETRY) {
6224                         /*
6225                          * Must release the reference to batch_last before
6226                          * scheduling and waiting for work to be done,
6227                          * otherwise the batch_last stripe head could prevent
6228                          * raid5_activate_delayed() from making progress
6229                          * and thus deadlocking.
6230                          */
6231                         if (ctx.batch_last) {
6232                                 raid5_release_stripe(ctx.batch_last);
6233                                 ctx.batch_last = NULL;
6234                         }
6235
6236                         wait_woken(&wait, TASK_UNINTERRUPTIBLE,
6237                                    MAX_SCHEDULE_TIMEOUT);
6238                         continue;
6239                 }
6240
6241                 s = find_next_bit_wrap(ctx.sectors_to_do, stripe_cnt, s);
6242                 if (s == stripe_cnt)
6243                         break;
6244
6245                 logical_sector = ctx.first_sector +
6246                         (s << RAID5_STRIPE_SHIFT(conf));
6247         }
6248         remove_wait_queue(&conf->wait_for_overlap, &wait);
6249
6250         if (ctx.batch_last)
6251                 raid5_release_stripe(ctx.batch_last);
6252
6253         if (rw == WRITE)
6254                 md_write_end(mddev);
6255         bio_endio(bi);
6256         return true;
6257 }
6258
6259 static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
6260
6261 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
6262 {
6263         /* reshaping is quite different to recovery/resync so it is
6264          * handled quite separately ... here.
6265          *
6266          * On each call to sync_request, we gather one chunk worth of
6267          * destination stripes and flag them as expanding.
6268          * Then we find all the source stripes and request reads.
6269          * As the reads complete, handle_stripe will copy the data
6270          * into the destination stripe and release that stripe.
6271          */
6272         struct r5conf *conf = mddev->private;
6273         struct stripe_head *sh;
6274         struct md_rdev *rdev;
6275         sector_t first_sector, last_sector;
6276         int raid_disks = conf->previous_raid_disks;
6277         int data_disks = raid_disks - conf->max_degraded;
6278         int new_data_disks = conf->raid_disks - conf->max_degraded;
6279         int i;
6280         int dd_idx;
6281         sector_t writepos, readpos, safepos;
6282         sector_t stripe_addr;
6283         int reshape_sectors;
6284         struct list_head stripes;
6285         sector_t retn;
6286
6287         if (sector_nr == 0) {
6288                 /* If restarting in the middle, skip the initial sectors */
6289                 if (mddev->reshape_backwards &&
6290                     conf->reshape_progress < raid5_size(mddev, 0, 0)) {
6291                         sector_nr = raid5_size(mddev, 0, 0)
6292                                 - conf->reshape_progress;
6293                 } else if (mddev->reshape_backwards &&
6294                            conf->reshape_progress == MaxSector) {
6295                         /* shouldn't happen, but just in case, finish up.*/
6296                         sector_nr = MaxSector;
6297                 } else if (!mddev->reshape_backwards &&
6298                            conf->reshape_progress > 0)
6299                         sector_nr = conf->reshape_progress;
6300                 sector_div(sector_nr, new_data_disks);
6301                 if (sector_nr) {
6302                         mddev->curr_resync_completed = sector_nr;
6303                         sysfs_notify_dirent_safe(mddev->sysfs_completed);
6304                         *skipped = 1;
6305                         retn = sector_nr;
6306                         goto finish;
6307                 }
6308         }
6309
6310         /* We need to process a full chunk at a time.
6311          * If old and new chunk sizes differ, we need to process the
6312          * largest of these
6313          */
6314
6315         reshape_sectors = max(conf->chunk_sectors, conf->prev_chunk_sectors);
6316
6317         /* We update the metadata at least every 10 seconds, or when
6318          * the data about to be copied would over-write the source of
6319          * the data at the front of the range.  i.e. one new_stripe
6320          * along from reshape_progress new_maps to after where
6321          * reshape_safe old_maps to
6322          */
6323         writepos = conf->reshape_progress;
6324         sector_div(writepos, new_data_disks);
6325         readpos = conf->reshape_progress;
6326         sector_div(readpos, data_disks);
6327         safepos = conf->reshape_safe;
6328         sector_div(safepos, data_disks);
6329         if (mddev->reshape_backwards) {
6330                 BUG_ON(writepos < reshape_sectors);
6331                 writepos -= reshape_sectors;
6332                 readpos += reshape_sectors;
6333                 safepos += reshape_sectors;
6334         } else {
6335                 writepos += reshape_sectors;
6336                 /* readpos and safepos are worst-case calculations.
6337                  * A negative number is overly pessimistic, and causes
6338                  * obvious problems for unsigned storage.  So clip to 0.
6339                  */
6340                 readpos -= min_t(sector_t, reshape_sectors, readpos);
6341                 safepos -= min_t(sector_t, reshape_sectors, safepos);
6342         }
6343
6344         /* Having calculated the 'writepos' possibly use it
6345          * to set 'stripe_addr' which is where we will write to.
6346          */
6347         if (mddev->reshape_backwards) {
6348                 BUG_ON(conf->reshape_progress == 0);
6349                 stripe_addr = writepos;
6350                 BUG_ON((mddev->dev_sectors &
6351                         ~((sector_t)reshape_sectors - 1))
6352                        - reshape_sectors - stripe_addr
6353                        != sector_nr);
6354         } else {
6355                 BUG_ON(writepos != sector_nr + reshape_sectors);
6356                 stripe_addr = sector_nr;
6357         }
6358
6359         /* 'writepos' is the most advanced device address we might write.
6360          * 'readpos' is the least advanced device address we might read.
6361          * 'safepos' is the least address recorded in the metadata as having
6362          *     been reshaped.
6363          * If there is a min_offset_diff, these are adjusted either by
6364          * increasing the safepos/readpos if diff is negative, or
6365          * increasing writepos if diff is positive.
6366          * If 'readpos' is then behind 'writepos', there is no way that we can
6367          * ensure safety in the face of a crash - that must be done by userspace
6368          * making a backup of the data.  So in that case there is no particular
6369          * rush to update metadata.
6370          * Otherwise if 'safepos' is behind 'writepos', then we really need to
6371          * update the metadata to advance 'safepos' to match 'readpos' so that
6372          * we can be safe in the event of a crash.
6373          * So we insist on updating metadata if safepos is behind writepos and
6374          * readpos is beyond writepos.
6375          * In any case, update the metadata every 10 seconds.
6376          * Maybe that number should be configurable, but I'm not sure it is
6377          * worth it.... maybe it could be a multiple of safemode_delay???
6378          */
6379         if (conf->min_offset_diff < 0) {
6380                 safepos += -conf->min_offset_diff;
6381                 readpos += -conf->min_offset_diff;
6382         } else
6383                 writepos += conf->min_offset_diff;
6384
6385         if ((mddev->reshape_backwards
6386              ? (safepos > writepos && readpos < writepos)
6387              : (safepos < writepos && readpos > writepos)) ||
6388             time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
6389                 /* Cannot proceed until we've updated the superblock... */
6390                 wait_event(conf->wait_for_overlap,
6391                            atomic_read(&conf->reshape_stripes)==0
6392                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6393                 if (atomic_read(&conf->reshape_stripes) != 0)
6394                         return 0;
6395                 mddev->reshape_position = conf->reshape_progress;
6396                 mddev->curr_resync_completed = sector_nr;
6397                 if (!mddev->reshape_backwards)
6398                         /* Can update recovery_offset */
6399                         rdev_for_each(rdev, mddev)
6400                                 if (rdev->raid_disk >= 0 &&
6401                                     !test_bit(Journal, &rdev->flags) &&
6402                                     !test_bit(In_sync, &rdev->flags) &&
6403                                     rdev->recovery_offset < sector_nr)
6404                                         rdev->recovery_offset = sector_nr;
6405
6406                 conf->reshape_checkpoint = jiffies;
6407                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
6408                 md_wakeup_thread(mddev->thread);
6409                 wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
6410                            test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6411                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6412                         return 0;
6413                 spin_lock_irq(&conf->device_lock);
6414                 conf->reshape_safe = mddev->reshape_position;
6415                 spin_unlock_irq(&conf->device_lock);
6416                 wake_up(&conf->wait_for_overlap);
6417                 sysfs_notify_dirent_safe(mddev->sysfs_completed);
6418         }
6419
6420         INIT_LIST_HEAD(&stripes);
6421         for (i = 0; i < reshape_sectors; i += RAID5_STRIPE_SECTORS(conf)) {
6422                 int j;
6423                 int skipped_disk = 0;
6424                 sh = raid5_get_active_stripe(conf, NULL, stripe_addr+i,
6425                                              R5_GAS_NOQUIESCE);
6426                 set_bit(STRIPE_EXPANDING, &sh->state);
6427                 atomic_inc(&conf->reshape_stripes);
6428                 /* If any of this stripe is beyond the end of the old
6429                  * array, then we need to zero those blocks
6430                  */
6431                 for (j=sh->disks; j--;) {
6432                         sector_t s;
6433                         if (j == sh->pd_idx)
6434                                 continue;
6435                         if (conf->level == 6 &&
6436                             j == sh->qd_idx)
6437                                 continue;
6438                         s = raid5_compute_blocknr(sh, j, 0);
6439                         if (s < raid5_size(mddev, 0, 0)) {
6440                                 skipped_disk = 1;
6441                                 continue;
6442                         }
6443                         memset(page_address(sh->dev[j].page), 0, RAID5_STRIPE_SIZE(conf));
6444                         set_bit(R5_Expanded, &sh->dev[j].flags);
6445                         set_bit(R5_UPTODATE, &sh->dev[j].flags);
6446                 }
6447                 if (!skipped_disk) {
6448                         set_bit(STRIPE_EXPAND_READY, &sh->state);
6449                         set_bit(STRIPE_HANDLE, &sh->state);
6450                 }
6451                 list_add(&sh->lru, &stripes);
6452         }
6453         spin_lock_irq(&conf->device_lock);
6454         if (mddev->reshape_backwards)
6455                 conf->reshape_progress -= reshape_sectors * new_data_disks;
6456         else
6457                 conf->reshape_progress += reshape_sectors * new_data_disks;
6458         spin_unlock_irq(&conf->device_lock);
6459         /* Ok, those stripe are ready. We can start scheduling
6460          * reads on the source stripes.
6461          * The source stripes are determined by mapping the first and last
6462          * block on the destination stripes.
6463          */
6464         first_sector =
6465                 raid5_compute_sector(conf, stripe_addr*(new_data_disks),
6466                                      1, &dd_idx, NULL);
6467         last_sector =
6468                 raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
6469                                             * new_data_disks - 1),
6470                                      1, &dd_idx, NULL);
6471         if (last_sector >= mddev->dev_sectors)
6472                 last_sector = mddev->dev_sectors - 1;
6473         while (first_sector <= last_sector) {
6474                 sh = raid5_get_active_stripe(conf, NULL, first_sector,
6475                                 R5_GAS_PREVIOUS | R5_GAS_NOQUIESCE);
6476                 set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
6477                 set_bit(STRIPE_HANDLE, &sh->state);
6478                 raid5_release_stripe(sh);
6479                 first_sector += RAID5_STRIPE_SECTORS(conf);
6480         }
6481         /* Now that the sources are clearly marked, we can release
6482          * the destination stripes
6483          */
6484         while (!list_empty(&stripes)) {
6485                 sh = list_entry(stripes.next, struct stripe_head, lru);
6486                 list_del_init(&sh->lru);
6487                 raid5_release_stripe(sh);
6488         }
6489         /* If this takes us to the resync_max point where we have to pause,
6490          * then we need to write out the superblock.
6491          */
6492         sector_nr += reshape_sectors;
6493         retn = reshape_sectors;
6494 finish:
6495         if (mddev->curr_resync_completed > mddev->resync_max ||
6496             (sector_nr - mddev->curr_resync_completed) * 2
6497             >= mddev->resync_max - mddev->curr_resync_completed) {
6498                 /* Cannot proceed until we've updated the superblock... */
6499                 wait_event(conf->wait_for_overlap,
6500                            atomic_read(&conf->reshape_stripes) == 0
6501                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6502                 if (atomic_read(&conf->reshape_stripes) != 0)
6503                         goto ret;
6504                 mddev->reshape_position = conf->reshape_progress;
6505                 mddev->curr_resync_completed = sector_nr;
6506                 if (!mddev->reshape_backwards)
6507                         /* Can update recovery_offset */
6508                         rdev_for_each(rdev, mddev)
6509                                 if (rdev->raid_disk >= 0 &&
6510                                     !test_bit(Journal, &rdev->flags) &&
6511                                     !test_bit(In_sync, &rdev->flags) &&
6512                                     rdev->recovery_offset < sector_nr)
6513                                         rdev->recovery_offset = sector_nr;
6514                 conf->reshape_checkpoint = jiffies;
6515                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
6516                 md_wakeup_thread(mddev->thread);
6517                 wait_event(mddev->sb_wait,
6518                            !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)
6519                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6520                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6521                         goto ret;
6522                 spin_lock_irq(&conf->device_lock);
6523                 conf->reshape_safe = mddev->reshape_position;
6524                 spin_unlock_irq(&conf->device_lock);
6525                 wake_up(&conf->wait_for_overlap);
6526                 sysfs_notify_dirent_safe(mddev->sysfs_completed);
6527         }
6528 ret:
6529         return retn;
6530 }
6531
6532 static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_nr,
6533                                           int *skipped)
6534 {
6535         struct r5conf *conf = mddev->private;
6536         struct stripe_head *sh;
6537         sector_t max_sector = mddev->dev_sectors;
6538         sector_t sync_blocks;
6539         int still_degraded = 0;
6540         int i;
6541
6542         if (sector_nr >= max_sector) {
6543                 /* just being told to finish up .. nothing much to do */
6544
6545                 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
6546                         end_reshape(conf);
6547                         return 0;
6548                 }
6549
6550                 if (mddev->curr_resync < max_sector) /* aborted */
6551                         md_bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
6552                                            &sync_blocks, 1);
6553                 else /* completed sync */
6554                         conf->fullsync = 0;
6555                 md_bitmap_close_sync(mddev->bitmap);
6556
6557                 return 0;
6558         }
6559
6560         /* Allow raid5_quiesce to complete */
6561         wait_event(conf->wait_for_overlap, conf->quiesce != 2);
6562
6563         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6564                 return reshape_request(mddev, sector_nr, skipped);
6565
6566         /* No need to check resync_max as we never do more than one
6567          * stripe, and as resync_max will always be on a chunk boundary,
6568          * if the check in md_do_sync didn't fire, there is no chance
6569          * of overstepping resync_max here
6570          */
6571
6572         /* if there is too many failed drives and we are trying
6573          * to resync, then assert that we are finished, because there is
6574          * nothing we can do.
6575          */
6576         if (mddev->degraded >= conf->max_degraded &&
6577             test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
6578                 sector_t rv = mddev->dev_sectors - sector_nr;
6579                 *skipped = 1;
6580                 return rv;
6581         }
6582         if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
6583             !conf->fullsync &&
6584             !md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
6585             sync_blocks >= RAID5_STRIPE_SECTORS(conf)) {
6586                 /* we can skip this block, and probably more */
6587                 do_div(sync_blocks, RAID5_STRIPE_SECTORS(conf));
6588                 *skipped = 1;
6589                 /* keep things rounded to whole stripes */
6590                 return sync_blocks * RAID5_STRIPE_SECTORS(conf);
6591         }
6592
6593         md_bitmap_cond_end_sync(mddev->bitmap, sector_nr, false);
6594
6595         sh = raid5_get_active_stripe(conf, NULL, sector_nr,
6596                                      R5_GAS_NOBLOCK);
6597         if (sh == NULL) {
6598                 sh = raid5_get_active_stripe(conf, NULL, sector_nr, 0);
6599                 /* make sure we don't swamp the stripe cache if someone else
6600                  * is trying to get access
6601                  */
6602                 schedule_timeout_uninterruptible(1);
6603         }
6604         /* Need to check if array will still be degraded after recovery/resync
6605          * Note in case of > 1 drive failures it's possible we're rebuilding
6606          * one drive while leaving another faulty drive in array.
6607          */
6608         rcu_read_lock();
6609         for (i = 0; i < conf->raid_disks; i++) {
6610                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
6611
6612                 if (rdev == NULL || test_bit(Faulty, &rdev->flags))
6613                         still_degraded = 1;
6614         }
6615         rcu_read_unlock();
6616
6617         md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
6618
6619         set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
6620         set_bit(STRIPE_HANDLE, &sh->state);
6621
6622         raid5_release_stripe(sh);
6623
6624         return RAID5_STRIPE_SECTORS(conf);
6625 }
6626
6627 static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio,
6628                                unsigned int offset)
6629 {
6630         /* We may not be able to submit a whole bio at once as there
6631          * may not be enough stripe_heads available.
6632          * We cannot pre-allocate enough stripe_heads as we may need
6633          * more than exist in the cache (if we allow ever large chunks).
6634          * So we do one stripe head at a time and record in
6635          * ->bi_hw_segments how many have been done.
6636          *
6637          * We *know* that this entire raid_bio is in one chunk, so
6638          * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
6639          */
6640         struct stripe_head *sh;
6641         int dd_idx;
6642         sector_t sector, logical_sector, last_sector;
6643         int scnt = 0;
6644         int handled = 0;
6645
6646         logical_sector = raid_bio->bi_iter.bi_sector &
6647                 ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
6648         sector = raid5_compute_sector(conf, logical_sector,
6649                                       0, &dd_idx, NULL);
6650         last_sector = bio_end_sector(raid_bio);
6651
6652         for (; logical_sector < last_sector;
6653              logical_sector += RAID5_STRIPE_SECTORS(conf),
6654                      sector += RAID5_STRIPE_SECTORS(conf),
6655                      scnt++) {
6656
6657                 if (scnt < offset)
6658                         /* already done this stripe */
6659                         continue;
6660
6661                 sh = raid5_get_active_stripe(conf, NULL, sector,
6662                                 R5_GAS_NOBLOCK | R5_GAS_NOQUIESCE);
6663                 if (!sh) {
6664                         /* failed to get a stripe - must wait */
6665                         conf->retry_read_aligned = raid_bio;
6666                         conf->retry_read_offset = scnt;
6667                         return handled;
6668                 }
6669
6670                 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0, 0)) {
6671                         raid5_release_stripe(sh);
6672                         conf->retry_read_aligned = raid_bio;
6673                         conf->retry_read_offset = scnt;
6674                         return handled;
6675                 }
6676
6677                 set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
6678                 handle_stripe(sh);
6679                 raid5_release_stripe(sh);
6680                 handled++;
6681         }
6682
6683         bio_endio(raid_bio);
6684
6685         if (atomic_dec_and_test(&conf->active_aligned_reads))
6686                 wake_up(&conf->wait_for_quiescent);
6687         return handled;
6688 }
6689
6690 static int handle_active_stripes(struct r5conf *conf, int group,
6691                                  struct r5worker *worker,
6692                                  struct list_head *temp_inactive_list)
6693                 __must_hold(&conf->device_lock)
6694 {
6695         struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
6696         int i, batch_size = 0, hash;
6697         bool release_inactive = false;
6698
6699         while (batch_size < MAX_STRIPE_BATCH &&
6700                         (sh = __get_priority_stripe(conf, group)) != NULL)
6701                 batch[batch_size++] = sh;
6702
6703         if (batch_size == 0) {
6704                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6705                         if (!list_empty(temp_inactive_list + i))
6706                                 break;
6707                 if (i == NR_STRIPE_HASH_LOCKS) {
6708                         spin_unlock_irq(&conf->device_lock);
6709                         log_flush_stripe_to_raid(conf);
6710                         spin_lock_irq(&conf->device_lock);
6711                         return batch_size;
6712                 }
6713                 release_inactive = true;
6714         }
6715         spin_unlock_irq(&conf->device_lock);
6716
6717         release_inactive_stripe_list(conf, temp_inactive_list,
6718                                      NR_STRIPE_HASH_LOCKS);
6719
6720         r5l_flush_stripe_to_raid(conf->log);
6721         if (release_inactive) {
6722                 spin_lock_irq(&conf->device_lock);
6723                 return 0;
6724         }
6725
6726         for (i = 0; i < batch_size; i++)
6727                 handle_stripe(batch[i]);
6728         log_write_stripe_run(conf);
6729
6730         cond_resched();
6731
6732         spin_lock_irq(&conf->device_lock);
6733         for (i = 0; i < batch_size; i++) {
6734                 hash = batch[i]->hash_lock_index;
6735                 __release_stripe(conf, batch[i], &temp_inactive_list[hash]);
6736         }
6737         return batch_size;
6738 }
6739
6740 static void raid5_do_work(struct work_struct *work)
6741 {
6742         struct r5worker *worker = container_of(work, struct r5worker, work);
6743         struct r5worker_group *group = worker->group;
6744         struct r5conf *conf = group->conf;
6745         struct mddev *mddev = conf->mddev;
6746         int group_id = group - conf->worker_groups;
6747         int handled;
6748         struct blk_plug plug;
6749
6750         pr_debug("+++ raid5worker active\n");
6751
6752         blk_start_plug(&plug);
6753         handled = 0;
6754         spin_lock_irq(&conf->device_lock);
6755         while (1) {
6756                 int batch_size, released;
6757
6758                 released = release_stripe_list(conf, worker->temp_inactive_list);
6759
6760                 batch_size = handle_active_stripes(conf, group_id, worker,
6761                                                    worker->temp_inactive_list);
6762                 worker->working = false;
6763                 if (!batch_size && !released)
6764                         break;
6765                 handled += batch_size;
6766                 wait_event_lock_irq(mddev->sb_wait,
6767                         !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
6768                         conf->device_lock);
6769         }
6770         pr_debug("%d stripes handled\n", handled);
6771
6772         spin_unlock_irq(&conf->device_lock);
6773
6774         flush_deferred_bios(conf);
6775
6776         r5l_flush_stripe_to_raid(conf->log);
6777
6778         async_tx_issue_pending_all();
6779         blk_finish_plug(&plug);
6780
6781         pr_debug("--- raid5worker inactive\n");
6782 }
6783
6784 /*
6785  * This is our raid5 kernel thread.
6786  *
6787  * We scan the hash table for stripes which can be handled now.
6788  * During the scan, completed stripes are saved for us by the interrupt
6789  * handler, so that they will not have to wait for our next wakeup.
6790  */
6791 static void raid5d(struct md_thread *thread)
6792 {
6793         struct mddev *mddev = thread->mddev;
6794         struct r5conf *conf = mddev->private;
6795         int handled;
6796         struct blk_plug plug;
6797
6798         pr_debug("+++ raid5d active\n");
6799
6800         md_check_recovery(mddev);
6801
6802         blk_start_plug(&plug);
6803         handled = 0;
6804         spin_lock_irq(&conf->device_lock);
6805         while (1) {
6806                 struct bio *bio;
6807                 int batch_size, released;
6808                 unsigned int offset;
6809
6810                 released = release_stripe_list(conf, conf->temp_inactive_list);
6811                 if (released)
6812                         clear_bit(R5_DID_ALLOC, &conf->cache_state);
6813
6814                 if (
6815                     !list_empty(&conf->bitmap_list)) {
6816                         /* Now is a good time to flush some bitmap updates */
6817                         conf->seq_flush++;
6818                         spin_unlock_irq(&conf->device_lock);
6819                         md_bitmap_unplug(mddev->bitmap);
6820                         spin_lock_irq(&conf->device_lock);
6821                         conf->seq_write = conf->seq_flush;
6822                         activate_bit_delay(conf, conf->temp_inactive_list);
6823                 }
6824                 raid5_activate_delayed(conf);
6825
6826                 while ((bio = remove_bio_from_retry(conf, &offset))) {
6827                         int ok;
6828                         spin_unlock_irq(&conf->device_lock);
6829                         ok = retry_aligned_read(conf, bio, offset);
6830                         spin_lock_irq(&conf->device_lock);
6831                         if (!ok)
6832                                 break;
6833                         handled++;
6834                 }
6835
6836                 batch_size = handle_active_stripes(conf, ANY_GROUP, NULL,
6837                                                    conf->temp_inactive_list);
6838                 if (!batch_size && !released)
6839                         break;
6840                 handled += batch_size;
6841
6842                 if (mddev->sb_flags & ~(1 << MD_SB_CHANGE_PENDING)) {
6843                         spin_unlock_irq(&conf->device_lock);
6844                         md_check_recovery(mddev);
6845                         spin_lock_irq(&conf->device_lock);
6846
6847                         /*
6848                          * Waiting on MD_SB_CHANGE_PENDING below may deadlock
6849                          * seeing md_check_recovery() is needed to clear
6850                          * the flag when using mdmon.
6851                          */
6852                         continue;
6853                 }
6854
6855                 wait_event_lock_irq(mddev->sb_wait,
6856                         !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
6857                         conf->device_lock);
6858         }
6859         pr_debug("%d stripes handled\n", handled);
6860
6861         spin_unlock_irq(&conf->device_lock);
6862         if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state) &&
6863             mutex_trylock(&conf->cache_size_mutex)) {
6864                 grow_one_stripe(conf, __GFP_NOWARN);
6865                 /* Set flag even if allocation failed.  This helps
6866                  * slow down allocation requests when mem is short
6867                  */
6868                 set_bit(R5_DID_ALLOC, &conf->cache_state);
6869                 mutex_unlock(&conf->cache_size_mutex);
6870         }
6871
6872         flush_deferred_bios(conf);
6873
6874         r5l_flush_stripe_to_raid(conf->log);
6875
6876         async_tx_issue_pending_all();
6877         blk_finish_plug(&plug);
6878
6879         pr_debug("--- raid5d inactive\n");
6880 }
6881
6882 static ssize_t
6883 raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
6884 {
6885         struct r5conf *conf;
6886         int ret = 0;
6887         spin_lock(&mddev->lock);
6888         conf = mddev->private;
6889         if (conf)
6890                 ret = sprintf(page, "%d\n", conf->min_nr_stripes);
6891         spin_unlock(&mddev->lock);
6892         return ret;
6893 }
6894
6895 int
6896 raid5_set_cache_size(struct mddev *mddev, int size)
6897 {
6898         int result = 0;
6899         struct r5conf *conf = mddev->private;
6900
6901         if (size <= 16 || size > 32768)
6902                 return -EINVAL;
6903
6904         conf->min_nr_stripes = size;
6905         mutex_lock(&conf->cache_size_mutex);
6906         while (size < conf->max_nr_stripes &&
6907                drop_one_stripe(conf))
6908                 ;
6909         mutex_unlock(&conf->cache_size_mutex);
6910
6911         md_allow_write(mddev);
6912
6913         mutex_lock(&conf->cache_size_mutex);
6914         while (size > conf->max_nr_stripes)
6915                 if (!grow_one_stripe(conf, GFP_KERNEL)) {
6916                         conf->min_nr_stripes = conf->max_nr_stripes;
6917                         result = -ENOMEM;
6918                         break;
6919                 }
6920         mutex_unlock(&conf->cache_size_mutex);
6921
6922         return result;
6923 }
6924 EXPORT_SYMBOL(raid5_set_cache_size);
6925
6926 static ssize_t
6927 raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
6928 {
6929         struct r5conf *conf;
6930         unsigned long new;
6931         int err;
6932
6933         if (len >= PAGE_SIZE)
6934                 return -EINVAL;
6935         if (kstrtoul(page, 10, &new))
6936                 return -EINVAL;
6937         err = mddev_lock(mddev);
6938         if (err)
6939                 return err;
6940         conf = mddev->private;
6941         if (!conf)
6942                 err = -ENODEV;
6943         else
6944                 err = raid5_set_cache_size(mddev, new);
6945         mddev_unlock(mddev);
6946
6947         return err ?: len;
6948 }
6949
6950 static struct md_sysfs_entry
6951 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
6952                                 raid5_show_stripe_cache_size,
6953                                 raid5_store_stripe_cache_size);
6954
6955 static ssize_t
6956 raid5_show_rmw_level(struct mddev  *mddev, char *page)
6957 {
6958         struct r5conf *conf = mddev->private;
6959         if (conf)
6960                 return sprintf(page, "%d\n", conf->rmw_level);
6961         else
6962                 return 0;
6963 }
6964
6965 static ssize_t
6966 raid5_store_rmw_level(struct mddev  *mddev, const char *page, size_t len)
6967 {
6968         struct r5conf *conf = mddev->private;
6969         unsigned long new;
6970
6971         if (!conf)
6972                 return -ENODEV;
6973
6974         if (len >= PAGE_SIZE)
6975                 return -EINVAL;
6976
6977         if (kstrtoul(page, 10, &new))
6978                 return -EINVAL;
6979
6980         if (new != PARITY_DISABLE_RMW && !raid6_call.xor_syndrome)
6981                 return -EINVAL;
6982
6983         if (new != PARITY_DISABLE_RMW &&
6984             new != PARITY_ENABLE_RMW &&
6985             new != PARITY_PREFER_RMW)
6986                 return -EINVAL;
6987
6988         conf->rmw_level = new;
6989         return len;
6990 }
6991
6992 static struct md_sysfs_entry
6993 raid5_rmw_level = __ATTR(rmw_level, S_IRUGO | S_IWUSR,
6994                          raid5_show_rmw_level,
6995                          raid5_store_rmw_level);
6996
6997 static ssize_t
6998 raid5_show_stripe_size(struct mddev  *mddev, char *page)
6999 {
7000         struct r5conf *conf;
7001         int ret = 0;
7002
7003         spin_lock(&mddev->lock);
7004         conf = mddev->private;
7005         if (conf)
7006                 ret = sprintf(page, "%lu\n", RAID5_STRIPE_SIZE(conf));
7007         spin_unlock(&mddev->lock);
7008         return ret;
7009 }
7010
7011 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
7012 static ssize_t
7013 raid5_store_stripe_size(struct mddev  *mddev, const char *page, size_t len)
7014 {
7015         struct r5conf *conf;
7016         unsigned long new;
7017         int err;
7018         int size;
7019
7020         if (len >= PAGE_SIZE)
7021                 return -EINVAL;
7022         if (kstrtoul(page, 10, &new))
7023                 return -EINVAL;
7024
7025         /*
7026          * The value should not be bigger than PAGE_SIZE. It requires to
7027          * be multiple of DEFAULT_STRIPE_SIZE and the value should be power
7028          * of two.
7029          */
7030         if (new % DEFAULT_STRIPE_SIZE != 0 ||
7031                         new > PAGE_SIZE || new == 0 ||
7032                         new != roundup_pow_of_two(new))
7033                 return -EINVAL;
7034
7035         err = mddev_lock(mddev);
7036         if (err)
7037                 return err;
7038
7039         conf = mddev->private;
7040         if (!conf) {
7041                 err = -ENODEV;
7042                 goto out_unlock;
7043         }
7044
7045         if (new == conf->stripe_size)
7046                 goto out_unlock;
7047
7048         pr_debug("md/raid: change stripe_size from %lu to %lu\n",
7049                         conf->stripe_size, new);
7050
7051         if (mddev->sync_thread ||
7052                 test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
7053                 mddev->reshape_position != MaxSector ||
7054                 mddev->sysfs_active) {
7055                 err = -EBUSY;
7056                 goto out_unlock;
7057         }
7058
7059         mddev_suspend(mddev);
7060         mutex_lock(&conf->cache_size_mutex);
7061         size = conf->max_nr_stripes;
7062
7063         shrink_stripes(conf);
7064
7065         conf->stripe_size = new;
7066         conf->stripe_shift = ilog2(new) - 9;
7067         conf->stripe_sectors = new >> 9;
7068         if (grow_stripes(conf, size)) {
7069                 pr_warn("md/raid:%s: couldn't allocate buffers\n",
7070                                 mdname(mddev));
7071                 err = -ENOMEM;
7072         }
7073         mutex_unlock(&conf->cache_size_mutex);
7074         mddev_resume(mddev);
7075
7076 out_unlock:
7077         mddev_unlock(mddev);
7078         return err ?: len;
7079 }
7080
7081 static struct md_sysfs_entry
7082 raid5_stripe_size = __ATTR(stripe_size, 0644,
7083                          raid5_show_stripe_size,
7084                          raid5_store_stripe_size);
7085 #else
7086 static struct md_sysfs_entry
7087 raid5_stripe_size = __ATTR(stripe_size, 0444,
7088                          raid5_show_stripe_size,
7089                          NULL);
7090 #endif
7091
7092 static ssize_t
7093 raid5_show_preread_threshold(struct mddev *mddev, char *page)
7094 {
7095         struct r5conf *conf;
7096         int ret = 0;
7097         spin_lock(&mddev->lock);
7098         conf = mddev->private;
7099         if (conf)
7100                 ret = sprintf(page, "%d\n", conf->bypass_threshold);
7101         spin_unlock(&mddev->lock);
7102         return ret;
7103 }
7104
7105 static ssize_t
7106 raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
7107 {
7108         struct r5conf *conf;
7109         unsigned long new;
7110         int err;
7111
7112         if (len >= PAGE_SIZE)
7113                 return -EINVAL;
7114         if (kstrtoul(page, 10, &new))
7115                 return -EINVAL;
7116
7117         err = mddev_lock(mddev);
7118         if (err)
7119                 return err;
7120         conf = mddev->private;
7121         if (!conf)
7122                 err = -ENODEV;
7123         else if (new > conf->min_nr_stripes)
7124                 err = -EINVAL;
7125         else
7126                 conf->bypass_threshold = new;
7127         mddev_unlock(mddev);
7128         return err ?: len;
7129 }
7130
7131 static struct md_sysfs_entry
7132 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
7133                                         S_IRUGO | S_IWUSR,
7134                                         raid5_show_preread_threshold,
7135                                         raid5_store_preread_threshold);
7136
7137 static ssize_t
7138 raid5_show_skip_copy(struct mddev *mddev, char *page)
7139 {
7140         struct r5conf *conf;
7141         int ret = 0;
7142         spin_lock(&mddev->lock);
7143         conf = mddev->private;
7144         if (conf)
7145                 ret = sprintf(page, "%d\n", conf->skip_copy);
7146         spin_unlock(&mddev->lock);
7147         return ret;
7148 }
7149
7150 static ssize_t
7151 raid5_store_skip_copy(struct mddev *mddev, const char *page, size_t len)
7152 {
7153         struct r5conf *conf;
7154         unsigned long new;
7155         int err;
7156
7157         if (len >= PAGE_SIZE)
7158                 return -EINVAL;
7159         if (kstrtoul(page, 10, &new))
7160                 return -EINVAL;
7161         new = !!new;
7162
7163         err = mddev_lock(mddev);
7164         if (err)
7165                 return err;
7166         conf = mddev->private;
7167         if (!conf)
7168                 err = -ENODEV;
7169         else if (new != conf->skip_copy) {
7170                 struct request_queue *q = mddev->queue;
7171
7172                 mddev_suspend(mddev);
7173                 conf->skip_copy = new;
7174                 if (new)
7175                         blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES, q);
7176                 else
7177                         blk_queue_flag_clear(QUEUE_FLAG_STABLE_WRITES, q);
7178                 mddev_resume(mddev);
7179         }
7180         mddev_unlock(mddev);
7181         return err ?: len;
7182 }
7183
7184 static struct md_sysfs_entry
7185 raid5_skip_copy = __ATTR(skip_copy, S_IRUGO | S_IWUSR,
7186                                         raid5_show_skip_copy,
7187                                         raid5_store_skip_copy);
7188
7189 static ssize_t
7190 stripe_cache_active_show(struct mddev *mddev, char *page)
7191 {
7192         struct r5conf *conf = mddev->private;
7193         if (conf)
7194                 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
7195         else
7196                 return 0;
7197 }
7198
7199 static struct md_sysfs_entry
7200 raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
7201
7202 static ssize_t
7203 raid5_show_group_thread_cnt(struct mddev *mddev, char *page)
7204 {
7205         struct r5conf *conf;
7206         int ret = 0;
7207         spin_lock(&mddev->lock);
7208         conf = mddev->private;
7209         if (conf)
7210                 ret = sprintf(page, "%d\n", conf->worker_cnt_per_group);
7211         spin_unlock(&mddev->lock);
7212         return ret;
7213 }
7214
7215 static int alloc_thread_groups(struct r5conf *conf, int cnt,
7216                                int *group_cnt,
7217                                struct r5worker_group **worker_groups);
7218 static ssize_t
7219 raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
7220 {
7221         struct r5conf *conf;
7222         unsigned int new;
7223         int err;
7224         struct r5worker_group *new_groups, *old_groups;
7225         int group_cnt;
7226
7227         if (len >= PAGE_SIZE)
7228                 return -EINVAL;
7229         if (kstrtouint(page, 10, &new))
7230                 return -EINVAL;
7231         /* 8192 should be big enough */
7232         if (new > 8192)
7233                 return -EINVAL;
7234
7235         err = mddev_lock(mddev);
7236         if (err)
7237                 return err;
7238         conf = mddev->private;
7239         if (!conf)
7240                 err = -ENODEV;
7241         else if (new != conf->worker_cnt_per_group) {
7242                 mddev_suspend(mddev);
7243
7244                 old_groups = conf->worker_groups;
7245                 if (old_groups)
7246                         flush_workqueue(raid5_wq);
7247
7248                 err = alloc_thread_groups(conf, new, &group_cnt, &new_groups);
7249                 if (!err) {
7250                         spin_lock_irq(&conf->device_lock);
7251                         conf->group_cnt = group_cnt;
7252                         conf->worker_cnt_per_group = new;
7253                         conf->worker_groups = new_groups;
7254                         spin_unlock_irq(&conf->device_lock);
7255
7256                         if (old_groups)
7257                                 kfree(old_groups[0].workers);
7258                         kfree(old_groups);
7259                 }
7260                 mddev_resume(mddev);
7261         }
7262         mddev_unlock(mddev);
7263
7264         return err ?: len;
7265 }
7266
7267 static struct md_sysfs_entry
7268 raid5_group_thread_cnt = __ATTR(group_thread_cnt, S_IRUGO | S_IWUSR,
7269                                 raid5_show_group_thread_cnt,
7270                                 raid5_store_group_thread_cnt);
7271
7272 static struct attribute *raid5_attrs[] =  {
7273         &raid5_stripecache_size.attr,
7274         &raid5_stripecache_active.attr,
7275         &raid5_preread_bypass_threshold.attr,
7276         &raid5_group_thread_cnt.attr,
7277         &raid5_skip_copy.attr,
7278         &raid5_rmw_level.attr,
7279         &raid5_stripe_size.attr,
7280         &r5c_journal_mode.attr,
7281         &ppl_write_hint.attr,
7282         NULL,
7283 };
7284 static const struct attribute_group raid5_attrs_group = {
7285         .name = NULL,
7286         .attrs = raid5_attrs,
7287 };
7288
7289 static int alloc_thread_groups(struct r5conf *conf, int cnt, int *group_cnt,
7290                                struct r5worker_group **worker_groups)
7291 {
7292         int i, j, k;
7293         ssize_t size;
7294         struct r5worker *workers;
7295
7296         if (cnt == 0) {
7297                 *group_cnt = 0;
7298                 *worker_groups = NULL;
7299                 return 0;
7300         }
7301         *group_cnt = num_possible_nodes();
7302         size = sizeof(struct r5worker) * cnt;
7303         workers = kcalloc(size, *group_cnt, GFP_NOIO);
7304         *worker_groups = kcalloc(*group_cnt, sizeof(struct r5worker_group),
7305                                  GFP_NOIO);
7306         if (!*worker_groups || !workers) {
7307                 kfree(workers);
7308                 kfree(*worker_groups);
7309                 return -ENOMEM;
7310         }
7311
7312         for (i = 0; i < *group_cnt; i++) {
7313                 struct r5worker_group *group;
7314
7315                 group = &(*worker_groups)[i];
7316                 INIT_LIST_HEAD(&group->handle_list);
7317                 INIT_LIST_HEAD(&group->loprio_list);
7318                 group->conf = conf;
7319                 group->workers = workers + i * cnt;
7320
7321                 for (j = 0; j < cnt; j++) {
7322                         struct r5worker *worker = group->workers + j;
7323                         worker->group = group;
7324                         INIT_WORK(&worker->work, raid5_do_work);
7325
7326                         for (k = 0; k < NR_STRIPE_HASH_LOCKS; k++)
7327                                 INIT_LIST_HEAD(worker->temp_inactive_list + k);
7328                 }
7329         }
7330
7331         return 0;
7332 }
7333
7334 static void free_thread_groups(struct r5conf *conf)
7335 {
7336         if (conf->worker_groups)
7337                 kfree(conf->worker_groups[0].workers);
7338         kfree(conf->worker_groups);
7339         conf->worker_groups = NULL;
7340 }
7341
7342 static sector_t
7343 raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
7344 {
7345         struct r5conf *conf = mddev->private;
7346
7347         if (!sectors)
7348                 sectors = mddev->dev_sectors;
7349         if (!raid_disks)
7350                 /* size is defined by the smallest of previous and new size */
7351                 raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
7352
7353         sectors &= ~((sector_t)conf->chunk_sectors - 1);
7354         sectors &= ~((sector_t)conf->prev_chunk_sectors - 1);
7355         return sectors * (raid_disks - conf->max_degraded);
7356 }
7357
7358 static void free_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
7359 {
7360         safe_put_page(percpu->spare_page);
7361         percpu->spare_page = NULL;
7362         kvfree(percpu->scribble);
7363         percpu->scribble = NULL;
7364 }
7365
7366 static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
7367 {
7368         if (conf->level == 6 && !percpu->spare_page) {
7369                 percpu->spare_page = alloc_page(GFP_KERNEL);
7370                 if (!percpu->spare_page)
7371                         return -ENOMEM;
7372         }
7373
7374         if (scribble_alloc(percpu,
7375                            max(conf->raid_disks,
7376                                conf->previous_raid_disks),
7377                            max(conf->chunk_sectors,
7378                                conf->prev_chunk_sectors)
7379                            / RAID5_STRIPE_SECTORS(conf))) {
7380                 free_scratch_buffer(conf, percpu);
7381                 return -ENOMEM;
7382         }
7383
7384         local_lock_init(&percpu->lock);
7385         return 0;
7386 }
7387
7388 static int raid456_cpu_dead(unsigned int cpu, struct hlist_node *node)
7389 {
7390         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
7391
7392         free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));
7393         return 0;
7394 }
7395
7396 static void raid5_free_percpu(struct r5conf *conf)
7397 {
7398         if (!conf->percpu)
7399                 return;
7400
7401         cpuhp_state_remove_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
7402         free_percpu(conf->percpu);
7403 }
7404
7405 static void free_conf(struct r5conf *conf)
7406 {
7407         int i;
7408
7409         log_exit(conf);
7410
7411         unregister_shrinker(&conf->shrinker);
7412         free_thread_groups(conf);
7413         shrink_stripes(conf);
7414         raid5_free_percpu(conf);
7415         for (i = 0; i < conf->pool_size; i++)
7416                 if (conf->disks[i].extra_page)
7417                         put_page(conf->disks[i].extra_page);
7418         kfree(conf->disks);
7419         bioset_exit(&conf->bio_split);
7420         kfree(conf->stripe_hashtbl);
7421         kfree(conf->pending_data);
7422         kfree(conf);
7423 }
7424
7425 static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
7426 {
7427         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
7428         struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);
7429
7430         if (alloc_scratch_buffer(conf, percpu)) {
7431                 pr_warn("%s: failed memory allocation for cpu%u\n",
7432                         __func__, cpu);
7433                 return -ENOMEM;
7434         }
7435         return 0;
7436 }
7437
7438 static int raid5_alloc_percpu(struct r5conf *conf)
7439 {
7440         int err = 0;
7441
7442         conf->percpu = alloc_percpu(struct raid5_percpu);
7443         if (!conf->percpu)
7444                 return -ENOMEM;
7445
7446         err = cpuhp_state_add_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
7447         if (!err) {
7448                 conf->scribble_disks = max(conf->raid_disks,
7449                         conf->previous_raid_disks);
7450                 conf->scribble_sectors = max(conf->chunk_sectors,
7451                         conf->prev_chunk_sectors);
7452         }
7453         return err;
7454 }
7455
7456 static unsigned long raid5_cache_scan(struct shrinker *shrink,
7457                                       struct shrink_control *sc)
7458 {
7459         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
7460         unsigned long ret = SHRINK_STOP;
7461
7462         if (mutex_trylock(&conf->cache_size_mutex)) {
7463                 ret= 0;
7464                 while (ret < sc->nr_to_scan &&
7465                        conf->max_nr_stripes > conf->min_nr_stripes) {
7466                         if (drop_one_stripe(conf) == 0) {
7467                                 ret = SHRINK_STOP;
7468                                 break;
7469                         }
7470                         ret++;
7471                 }
7472                 mutex_unlock(&conf->cache_size_mutex);
7473         }
7474         return ret;
7475 }
7476
7477 static unsigned long raid5_cache_count(struct shrinker *shrink,
7478                                        struct shrink_control *sc)
7479 {
7480         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
7481
7482         if (conf->max_nr_stripes < conf->min_nr_stripes)
7483                 /* unlikely, but not impossible */
7484                 return 0;
7485         return conf->max_nr_stripes - conf->min_nr_stripes;
7486 }
7487
7488 static struct r5conf *setup_conf(struct mddev *mddev)
7489 {
7490         struct r5conf *conf;
7491         int raid_disk, memory, max_disks;
7492         struct md_rdev *rdev;
7493         struct disk_info *disk;
7494         char pers_name[6];
7495         int i;
7496         int group_cnt;
7497         struct r5worker_group *new_group;
7498         int ret = -ENOMEM;
7499
7500         if (mddev->new_level != 5
7501             && mddev->new_level != 4
7502             && mddev->new_level != 6) {
7503                 pr_warn("md/raid:%s: raid level not set to 4/5/6 (%d)\n",
7504                         mdname(mddev), mddev->new_level);
7505                 return ERR_PTR(-EIO);
7506         }
7507         if ((mddev->new_level == 5
7508              && !algorithm_valid_raid5(mddev->new_layout)) ||
7509             (mddev->new_level == 6
7510              && !algorithm_valid_raid6(mddev->new_layout))) {
7511                 pr_warn("md/raid:%s: layout %d not supported\n",
7512                         mdname(mddev), mddev->new_layout);
7513                 return ERR_PTR(-EIO);
7514         }
7515         if (mddev->new_level == 6 && mddev->raid_disks < 4) {
7516                 pr_warn("md/raid:%s: not enough configured devices (%d, minimum 4)\n",
7517                         mdname(mddev), mddev->raid_disks);
7518                 return ERR_PTR(-EINVAL);
7519         }
7520
7521         if (!mddev->new_chunk_sectors ||
7522             (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
7523             !is_power_of_2(mddev->new_chunk_sectors)) {
7524                 pr_warn("md/raid:%s: invalid chunk size %d\n",
7525                         mdname(mddev), mddev->new_chunk_sectors << 9);
7526                 return ERR_PTR(-EINVAL);
7527         }
7528
7529         conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
7530         if (conf == NULL)
7531                 goto abort;
7532
7533 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
7534         conf->stripe_size = DEFAULT_STRIPE_SIZE;
7535         conf->stripe_shift = ilog2(DEFAULT_STRIPE_SIZE) - 9;
7536         conf->stripe_sectors = DEFAULT_STRIPE_SIZE >> 9;
7537 #endif
7538         INIT_LIST_HEAD(&conf->free_list);
7539         INIT_LIST_HEAD(&conf->pending_list);
7540         conf->pending_data = kcalloc(PENDING_IO_MAX,
7541                                      sizeof(struct r5pending_data),
7542                                      GFP_KERNEL);
7543         if (!conf->pending_data)
7544                 goto abort;
7545         for (i = 0; i < PENDING_IO_MAX; i++)
7546                 list_add(&conf->pending_data[i].sibling, &conf->free_list);
7547         /* Don't enable multi-threading by default*/
7548         if (!alloc_thread_groups(conf, 0, &group_cnt, &new_group)) {
7549                 conf->group_cnt = group_cnt;
7550                 conf->worker_cnt_per_group = 0;
7551                 conf->worker_groups = new_group;
7552         } else
7553                 goto abort;
7554         spin_lock_init(&conf->device_lock);
7555         seqcount_spinlock_init(&conf->gen_lock, &conf->device_lock);
7556         mutex_init(&conf->cache_size_mutex);
7557
7558         init_waitqueue_head(&conf->wait_for_quiescent);
7559         init_waitqueue_head(&conf->wait_for_stripe);
7560         init_waitqueue_head(&conf->wait_for_overlap);
7561         INIT_LIST_HEAD(&conf->handle_list);
7562         INIT_LIST_HEAD(&conf->loprio_list);
7563         INIT_LIST_HEAD(&conf->hold_list);
7564         INIT_LIST_HEAD(&conf->delayed_list);
7565         INIT_LIST_HEAD(&conf->bitmap_list);
7566         init_llist_head(&conf->released_stripes);
7567         atomic_set(&conf->active_stripes, 0);
7568         atomic_set(&conf->preread_active_stripes, 0);
7569         atomic_set(&conf->active_aligned_reads, 0);
7570         spin_lock_init(&conf->pending_bios_lock);
7571         conf->batch_bio_dispatch = true;
7572         rdev_for_each(rdev, mddev) {
7573                 if (test_bit(Journal, &rdev->flags))
7574                         continue;
7575                 if (bdev_nonrot(rdev->bdev)) {
7576                         conf->batch_bio_dispatch = false;
7577                         break;
7578                 }
7579         }
7580
7581         conf->bypass_threshold = BYPASS_THRESHOLD;
7582         conf->recovery_disabled = mddev->recovery_disabled - 1;
7583
7584         conf->raid_disks = mddev->raid_disks;
7585         if (mddev->reshape_position == MaxSector)
7586                 conf->previous_raid_disks = mddev->raid_disks;
7587         else
7588                 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
7589         max_disks = max(conf->raid_disks, conf->previous_raid_disks);
7590
7591         conf->disks = kcalloc(max_disks, sizeof(struct disk_info),
7592                               GFP_KERNEL);
7593
7594         if (!conf->disks)
7595                 goto abort;
7596
7597         for (i = 0; i < max_disks; i++) {
7598                 conf->disks[i].extra_page = alloc_page(GFP_KERNEL);
7599                 if (!conf->disks[i].extra_page)
7600                         goto abort;
7601         }
7602
7603         ret = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
7604         if (ret)
7605                 goto abort;
7606         conf->mddev = mddev;
7607
7608         ret = -ENOMEM;
7609         conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL);
7610         if (!conf->stripe_hashtbl)
7611                 goto abort;
7612
7613         /* We init hash_locks[0] separately to that it can be used
7614          * as the reference lock in the spin_lock_nest_lock() call
7615          * in lock_all_device_hash_locks_irq in order to convince
7616          * lockdep that we know what we are doing.
7617          */
7618         spin_lock_init(conf->hash_locks);
7619         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
7620                 spin_lock_init(conf->hash_locks + i);
7621
7622         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
7623                 INIT_LIST_HEAD(conf->inactive_list + i);
7624
7625         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
7626                 INIT_LIST_HEAD(conf->temp_inactive_list + i);
7627
7628         atomic_set(&conf->r5c_cached_full_stripes, 0);
7629         INIT_LIST_HEAD(&conf->r5c_full_stripe_list);
7630         atomic_set(&conf->r5c_cached_partial_stripes, 0);
7631         INIT_LIST_HEAD(&conf->r5c_partial_stripe_list);
7632         atomic_set(&conf->r5c_flushing_full_stripes, 0);
7633         atomic_set(&conf->r5c_flushing_partial_stripes, 0);
7634
7635         conf->level = mddev->new_level;
7636         conf->chunk_sectors = mddev->new_chunk_sectors;
7637         ret = raid5_alloc_percpu(conf);
7638         if (ret)
7639                 goto abort;
7640
7641         pr_debug("raid456: run(%s) called.\n", mdname(mddev));
7642
7643         ret = -EIO;
7644         rdev_for_each(rdev, mddev) {
7645                 raid_disk = rdev->raid_disk;
7646                 if (raid_disk >= max_disks
7647                     || raid_disk < 0 || test_bit(Journal, &rdev->flags))
7648                         continue;
7649                 disk = conf->disks + raid_disk;
7650
7651                 if (test_bit(Replacement, &rdev->flags)) {
7652                         if (disk->replacement)
7653                                 goto abort;
7654                         RCU_INIT_POINTER(disk->replacement, rdev);
7655                 } else {
7656                         if (disk->rdev)
7657                                 goto abort;
7658                         RCU_INIT_POINTER(disk->rdev, rdev);
7659                 }
7660
7661                 if (test_bit(In_sync, &rdev->flags)) {
7662                         pr_info("md/raid:%s: device %pg operational as raid disk %d\n",
7663                                 mdname(mddev), rdev->bdev, raid_disk);
7664                 } else if (rdev->saved_raid_disk != raid_disk)
7665                         /* Cannot rely on bitmap to complete recovery */
7666                         conf->fullsync = 1;
7667         }
7668
7669         conf->level = mddev->new_level;
7670         if (conf->level == 6) {
7671                 conf->max_degraded = 2;
7672                 if (raid6_call.xor_syndrome)
7673                         conf->rmw_level = PARITY_ENABLE_RMW;
7674                 else
7675                         conf->rmw_level = PARITY_DISABLE_RMW;
7676         } else {
7677                 conf->max_degraded = 1;
7678                 conf->rmw_level = PARITY_ENABLE_RMW;
7679         }
7680         conf->algorithm = mddev->new_layout;
7681         conf->reshape_progress = mddev->reshape_position;
7682         if (conf->reshape_progress != MaxSector) {
7683                 conf->prev_chunk_sectors = mddev->chunk_sectors;
7684                 conf->prev_algo = mddev->layout;
7685         } else {
7686                 conf->prev_chunk_sectors = conf->chunk_sectors;
7687                 conf->prev_algo = conf->algorithm;
7688         }
7689
7690         conf->min_nr_stripes = NR_STRIPES;
7691         if (mddev->reshape_position != MaxSector) {
7692                 int stripes = max_t(int,
7693                         ((mddev->chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4,
7694                         ((mddev->new_chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4);
7695                 conf->min_nr_stripes = max(NR_STRIPES, stripes);
7696                 if (conf->min_nr_stripes != NR_STRIPES)
7697                         pr_info("md/raid:%s: force stripe size %d for reshape\n",
7698                                 mdname(mddev), conf->min_nr_stripes);
7699         }
7700         memory = conf->min_nr_stripes * (sizeof(struct stripe_head) +
7701                  max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
7702         atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS);
7703         if (grow_stripes(conf, conf->min_nr_stripes)) {
7704                 pr_warn("md/raid:%s: couldn't allocate %dkB for buffers\n",
7705                         mdname(mddev), memory);
7706                 ret = -ENOMEM;
7707                 goto abort;
7708         } else
7709                 pr_debug("md/raid:%s: allocated %dkB\n", mdname(mddev), memory);
7710         /*
7711          * Losing a stripe head costs more than the time to refill it,
7712          * it reduces the queue depth and so can hurt throughput.
7713          * So set it rather large, scaled by number of devices.
7714          */
7715         conf->shrinker.seeks = DEFAULT_SEEKS * conf->raid_disks * 4;
7716         conf->shrinker.scan_objects = raid5_cache_scan;
7717         conf->shrinker.count_objects = raid5_cache_count;
7718         conf->shrinker.batch = 128;
7719         conf->shrinker.flags = 0;
7720         ret = register_shrinker(&conf->shrinker, "md-raid5:%s", mdname(mddev));
7721         if (ret) {
7722                 pr_warn("md/raid:%s: couldn't register shrinker.\n",
7723                         mdname(mddev));
7724                 goto abort;
7725         }
7726
7727         sprintf(pers_name, "raid%d", mddev->new_level);
7728         rcu_assign_pointer(conf->thread,
7729                            md_register_thread(raid5d, mddev, pers_name));
7730         if (!conf->thread) {
7731                 pr_warn("md/raid:%s: couldn't allocate thread.\n",
7732                         mdname(mddev));
7733                 ret = -ENOMEM;
7734                 goto abort;
7735         }
7736
7737         return conf;
7738
7739  abort:
7740         if (conf)
7741                 free_conf(conf);
7742         return ERR_PTR(ret);
7743 }
7744
7745 static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
7746 {
7747         switch (algo) {
7748         case ALGORITHM_PARITY_0:
7749                 if (raid_disk < max_degraded)
7750                         return 1;
7751                 break;
7752         case ALGORITHM_PARITY_N:
7753                 if (raid_disk >= raid_disks - max_degraded)
7754                         return 1;
7755                 break;
7756         case ALGORITHM_PARITY_0_6:
7757                 if (raid_disk == 0 ||
7758                     raid_disk == raid_disks - 1)
7759                         return 1;
7760                 break;
7761         case ALGORITHM_LEFT_ASYMMETRIC_6:
7762         case ALGORITHM_RIGHT_ASYMMETRIC_6:
7763         case ALGORITHM_LEFT_SYMMETRIC_6:
7764         case ALGORITHM_RIGHT_SYMMETRIC_6:
7765                 if (raid_disk == raid_disks - 1)
7766                         return 1;
7767         }
7768         return 0;
7769 }
7770
7771 static void raid5_set_io_opt(struct r5conf *conf)
7772 {
7773         blk_queue_io_opt(conf->mddev->queue, (conf->chunk_sectors << 9) *
7774                          (conf->raid_disks - conf->max_degraded));
7775 }
7776
7777 static int raid5_run(struct mddev *mddev)
7778 {
7779         struct r5conf *conf;
7780         int dirty_parity_disks = 0;
7781         struct md_rdev *rdev;
7782         struct md_rdev *journal_dev = NULL;
7783         sector_t reshape_offset = 0;
7784         int i;
7785         long long min_offset_diff = 0;
7786         int first = 1;
7787
7788         if (mddev_init_writes_pending(mddev) < 0)
7789                 return -ENOMEM;
7790
7791         if (mddev->recovery_cp != MaxSector)
7792                 pr_notice("md/raid:%s: not clean -- starting background reconstruction\n",
7793                           mdname(mddev));
7794
7795         rdev_for_each(rdev, mddev) {
7796                 long long diff;
7797
7798                 if (test_bit(Journal, &rdev->flags)) {
7799                         journal_dev = rdev;
7800                         continue;
7801                 }
7802                 if (rdev->raid_disk < 0)
7803                         continue;
7804                 diff = (rdev->new_data_offset - rdev->data_offset);
7805                 if (first) {
7806                         min_offset_diff = diff;
7807                         first = 0;
7808                 } else if (mddev->reshape_backwards &&
7809                          diff < min_offset_diff)
7810                         min_offset_diff = diff;
7811                 else if (!mddev->reshape_backwards &&
7812                          diff > min_offset_diff)
7813                         min_offset_diff = diff;
7814         }
7815
7816         if ((test_bit(MD_HAS_JOURNAL, &mddev->flags) || journal_dev) &&
7817             (mddev->bitmap_info.offset || mddev->bitmap_info.file)) {
7818                 pr_notice("md/raid:%s: array cannot have both journal and bitmap\n",
7819                           mdname(mddev));
7820                 return -EINVAL;
7821         }
7822
7823         if (mddev->reshape_position != MaxSector) {
7824                 /* Check that we can continue the reshape.
7825                  * Difficulties arise if the stripe we would write to
7826                  * next is at or after the stripe we would read from next.
7827                  * For a reshape that changes the number of devices, this
7828                  * is only possible for a very short time, and mdadm makes
7829                  * sure that time appears to have past before assembling
7830                  * the array.  So we fail if that time hasn't passed.
7831                  * For a reshape that keeps the number of devices the same
7832                  * mdadm must be monitoring the reshape can keeping the
7833                  * critical areas read-only and backed up.  It will start
7834                  * the array in read-only mode, so we check for that.
7835                  */
7836                 sector_t here_new, here_old;
7837                 int old_disks;
7838                 int max_degraded = (mddev->level == 6 ? 2 : 1);
7839                 int chunk_sectors;
7840                 int new_data_disks;
7841
7842                 if (journal_dev) {
7843                         pr_warn("md/raid:%s: don't support reshape with journal - aborting.\n",
7844                                 mdname(mddev));
7845                         return -EINVAL;
7846                 }
7847
7848                 if (mddev->new_level != mddev->level) {
7849                         pr_warn("md/raid:%s: unsupported reshape required - aborting.\n",
7850                                 mdname(mddev));
7851                         return -EINVAL;
7852                 }
7853                 old_disks = mddev->raid_disks - mddev->delta_disks;
7854                 /* reshape_position must be on a new-stripe boundary, and one
7855                  * further up in new geometry must map after here in old
7856                  * geometry.
7857                  * If the chunk sizes are different, then as we perform reshape
7858                  * in units of the largest of the two, reshape_position needs
7859                  * be a multiple of the largest chunk size times new data disks.
7860                  */
7861                 here_new = mddev->reshape_position;
7862                 chunk_sectors = max(mddev->chunk_sectors, mddev->new_chunk_sectors);
7863                 new_data_disks = mddev->raid_disks - max_degraded;
7864                 if (sector_div(here_new, chunk_sectors * new_data_disks)) {
7865                         pr_warn("md/raid:%s: reshape_position not on a stripe boundary\n",
7866                                 mdname(mddev));
7867                         return -EINVAL;
7868                 }
7869                 reshape_offset = here_new * chunk_sectors;
7870                 /* here_new is the stripe we will write to */
7871                 here_old = mddev->reshape_position;
7872                 sector_div(here_old, chunk_sectors * (old_disks-max_degraded));
7873                 /* here_old is the first stripe that we might need to read
7874                  * from */
7875                 if (mddev->delta_disks == 0) {
7876                         /* We cannot be sure it is safe to start an in-place
7877                          * reshape.  It is only safe if user-space is monitoring
7878                          * and taking constant backups.
7879                          * mdadm always starts a situation like this in
7880                          * readonly mode so it can take control before
7881                          * allowing any writes.  So just check for that.
7882                          */
7883                         if (abs(min_offset_diff) >= mddev->chunk_sectors &&
7884                             abs(min_offset_diff) >= mddev->new_chunk_sectors)
7885                                 /* not really in-place - so OK */;
7886                         else if (mddev->ro == 0) {
7887                                 pr_warn("md/raid:%s: in-place reshape must be started in read-only mode - aborting\n",
7888                                         mdname(mddev));
7889                                 return -EINVAL;
7890                         }
7891                 } else if (mddev->reshape_backwards
7892                     ? (here_new * chunk_sectors + min_offset_diff <=
7893                        here_old * chunk_sectors)
7894                     : (here_new * chunk_sectors >=
7895                        here_old * chunk_sectors + (-min_offset_diff))) {
7896                         /* Reading from the same stripe as writing to - bad */
7897                         pr_warn("md/raid:%s: reshape_position too early for auto-recovery - aborting.\n",
7898                                 mdname(mddev));
7899                         return -EINVAL;
7900                 }
7901                 pr_debug("md/raid:%s: reshape will continue\n", mdname(mddev));
7902                 /* OK, we should be able to continue; */
7903         } else {
7904                 BUG_ON(mddev->level != mddev->new_level);
7905                 BUG_ON(mddev->layout != mddev->new_layout);
7906                 BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
7907                 BUG_ON(mddev->delta_disks != 0);
7908         }
7909
7910         if (test_bit(MD_HAS_JOURNAL, &mddev->flags) &&
7911             test_bit(MD_HAS_PPL, &mddev->flags)) {
7912                 pr_warn("md/raid:%s: using journal device and PPL not allowed - disabling PPL\n",
7913                         mdname(mddev));
7914                 clear_bit(MD_HAS_PPL, &mddev->flags);
7915                 clear_bit(MD_HAS_MULTIPLE_PPLS, &mddev->flags);
7916         }
7917
7918         if (mddev->private == NULL)
7919                 conf = setup_conf(mddev);
7920         else
7921                 conf = mddev->private;
7922
7923         if (IS_ERR(conf))
7924                 return PTR_ERR(conf);
7925
7926         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
7927                 if (!journal_dev) {
7928                         pr_warn("md/raid:%s: journal disk is missing, force array readonly\n",
7929                                 mdname(mddev));
7930                         mddev->ro = 1;
7931                         set_disk_ro(mddev->gendisk, 1);
7932                 } else if (mddev->recovery_cp == MaxSector)
7933                         set_bit(MD_JOURNAL_CLEAN, &mddev->flags);
7934         }
7935
7936         conf->min_offset_diff = min_offset_diff;
7937         rcu_assign_pointer(mddev->thread, conf->thread);
7938         rcu_assign_pointer(conf->thread, NULL);
7939         mddev->private = conf;
7940
7941         for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
7942              i++) {
7943                 rdev = rdev_mdlock_deref(mddev, conf->disks[i].rdev);
7944                 if (!rdev && conf->disks[i].replacement) {
7945                         /* The replacement is all we have yet */
7946                         rdev = rdev_mdlock_deref(mddev,
7947                                                  conf->disks[i].replacement);
7948                         conf->disks[i].replacement = NULL;
7949                         clear_bit(Replacement, &rdev->flags);
7950                         rcu_assign_pointer(conf->disks[i].rdev, rdev);
7951                 }
7952                 if (!rdev)
7953                         continue;
7954                 if (rcu_access_pointer(conf->disks[i].replacement) &&
7955                     conf->reshape_progress != MaxSector) {
7956                         /* replacements and reshape simply do not mix. */
7957                         pr_warn("md: cannot handle concurrent replacement and reshape.\n");
7958                         goto abort;
7959                 }
7960                 if (test_bit(In_sync, &rdev->flags))
7961                         continue;
7962                 /* This disc is not fully in-sync.  However if it
7963                  * just stored parity (beyond the recovery_offset),
7964                  * when we don't need to be concerned about the
7965                  * array being dirty.
7966                  * When reshape goes 'backwards', we never have
7967                  * partially completed devices, so we only need
7968                  * to worry about reshape going forwards.
7969                  */
7970                 /* Hack because v0.91 doesn't store recovery_offset properly. */
7971                 if (mddev->major_version == 0 &&
7972                     mddev->minor_version > 90)
7973                         rdev->recovery_offset = reshape_offset;
7974
7975                 if (rdev->recovery_offset < reshape_offset) {
7976                         /* We need to check old and new layout */
7977                         if (!only_parity(rdev->raid_disk,
7978                                          conf->algorithm,
7979                                          conf->raid_disks,
7980                                          conf->max_degraded))
7981                                 continue;
7982                 }
7983                 if (!only_parity(rdev->raid_disk,
7984                                  conf->prev_algo,
7985                                  conf->previous_raid_disks,
7986                                  conf->max_degraded))
7987                         continue;
7988                 dirty_parity_disks++;
7989         }
7990
7991         /*
7992          * 0 for a fully functional array, 1 or 2 for a degraded array.
7993          */
7994         mddev->degraded = raid5_calc_degraded(conf);
7995
7996         if (has_failed(conf)) {
7997                 pr_crit("md/raid:%s: not enough operational devices (%d/%d failed)\n",
7998                         mdname(mddev), mddev->degraded, conf->raid_disks);
7999                 goto abort;
8000         }
8001
8002         /* device size must be a multiple of chunk size */
8003         mddev->dev_sectors &= ~((sector_t)mddev->chunk_sectors - 1);
8004         mddev->resync_max_sectors = mddev->dev_sectors;
8005
8006         if (mddev->degraded > dirty_parity_disks &&
8007             mddev->recovery_cp != MaxSector) {
8008                 if (test_bit(MD_HAS_PPL, &mddev->flags))
8009                         pr_crit("md/raid:%s: starting dirty degraded array with PPL.\n",
8010                                 mdname(mddev));
8011                 else if (mddev->ok_start_degraded)
8012                         pr_crit("md/raid:%s: starting dirty degraded array - data corruption possible.\n",
8013                                 mdname(mddev));
8014                 else {
8015                         pr_crit("md/raid:%s: cannot start dirty degraded array.\n",
8016                                 mdname(mddev));
8017                         goto abort;
8018                 }
8019         }
8020
8021         pr_info("md/raid:%s: raid level %d active with %d out of %d devices, algorithm %d\n",
8022                 mdname(mddev), conf->level,
8023                 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
8024                 mddev->new_layout);
8025
8026         print_raid5_conf(conf);
8027
8028         if (conf->reshape_progress != MaxSector) {
8029                 conf->reshape_safe = conf->reshape_progress;
8030                 atomic_set(&conf->reshape_stripes, 0);
8031                 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
8032                 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
8033                 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
8034                 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
8035                 rcu_assign_pointer(mddev->sync_thread,
8036                         md_register_thread(md_do_sync, mddev, "reshape"));
8037                 if (!mddev->sync_thread)
8038                         goto abort;
8039         }
8040
8041         /* Ok, everything is just fine now */
8042         if (mddev->to_remove == &raid5_attrs_group)
8043                 mddev->to_remove = NULL;
8044         else if (mddev->kobj.sd &&
8045             sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
8046                 pr_warn("raid5: failed to create sysfs attributes for %s\n",
8047                         mdname(mddev));
8048         md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
8049
8050         if (mddev->queue) {
8051                 int chunk_size;
8052                 /* read-ahead size must cover two whole stripes, which
8053                  * is 2 * (datadisks) * chunksize where 'n' is the
8054                  * number of raid devices
8055                  */
8056                 int data_disks = conf->previous_raid_disks - conf->max_degraded;
8057                 int stripe = data_disks *
8058                         ((mddev->chunk_sectors << 9) / PAGE_SIZE);
8059
8060                 chunk_size = mddev->chunk_sectors << 9;
8061                 blk_queue_io_min(mddev->queue, chunk_size);
8062                 raid5_set_io_opt(conf);
8063                 mddev->queue->limits.raid_partial_stripes_expensive = 1;
8064                 /*
8065                  * We can only discard a whole stripe. It doesn't make sense to
8066                  * discard data disk but write parity disk
8067                  */
8068                 stripe = stripe * PAGE_SIZE;
8069                 stripe = roundup_pow_of_two(stripe);
8070                 mddev->queue->limits.discard_granularity = stripe;
8071
8072                 blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
8073
8074                 rdev_for_each(rdev, mddev) {
8075                         disk_stack_limits(mddev->gendisk, rdev->bdev,
8076                                           rdev->data_offset << 9);
8077                         disk_stack_limits(mddev->gendisk, rdev->bdev,
8078                                           rdev->new_data_offset << 9);
8079                 }
8080
8081                 /*
8082                  * zeroing is required, otherwise data
8083                  * could be lost. Consider a scenario: discard a stripe
8084                  * (the stripe could be inconsistent if
8085                  * discard_zeroes_data is 0); write one disk of the
8086                  * stripe (the stripe could be inconsistent again
8087                  * depending on which disks are used to calculate
8088                  * parity); the disk is broken; The stripe data of this
8089                  * disk is lost.
8090                  *
8091                  * We only allow DISCARD if the sysadmin has confirmed that
8092                  * only safe devices are in use by setting a module parameter.
8093                  * A better idea might be to turn DISCARD into WRITE_ZEROES
8094                  * requests, as that is required to be safe.
8095                  */
8096                 if (!devices_handle_discard_safely ||
8097                     mddev->queue->limits.max_discard_sectors < (stripe >> 9) ||
8098                     mddev->queue->limits.discard_granularity < stripe)
8099                         blk_queue_max_discard_sectors(mddev->queue, 0);
8100
8101                 /*
8102                  * Requests require having a bitmap for each stripe.
8103                  * Limit the max sectors based on this.
8104                  */
8105                 blk_queue_max_hw_sectors(mddev->queue,
8106                         RAID5_MAX_REQ_STRIPES << RAID5_STRIPE_SHIFT(conf));
8107
8108                 /* No restrictions on the number of segments in the request */
8109                 blk_queue_max_segments(mddev->queue, USHRT_MAX);
8110         }
8111
8112         if (log_init(conf, journal_dev, raid5_has_ppl(conf)))
8113                 goto abort;
8114
8115         return 0;
8116 abort:
8117         md_unregister_thread(mddev, &mddev->thread);
8118         print_raid5_conf(conf);
8119         free_conf(conf);
8120         mddev->private = NULL;
8121         pr_warn("md/raid:%s: failed to run raid set.\n", mdname(mddev));
8122         return -EIO;
8123 }
8124
8125 static void raid5_free(struct mddev *mddev, void *priv)
8126 {
8127         struct r5conf *conf = priv;
8128
8129         free_conf(conf);
8130         mddev->to_remove = &raid5_attrs_group;
8131 }
8132
8133 static void raid5_status(struct seq_file *seq, struct mddev *mddev)
8134 {
8135         struct r5conf *conf = mddev->private;
8136         int i;
8137
8138         seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
8139                 conf->chunk_sectors / 2, mddev->layout);
8140         seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
8141         rcu_read_lock();
8142         for (i = 0; i < conf->raid_disks; i++) {
8143                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
8144                 seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
8145         }
8146         rcu_read_unlock();
8147         seq_printf (seq, "]");
8148 }
8149
8150 static void print_raid5_conf (struct r5conf *conf)
8151 {
8152         struct md_rdev *rdev;
8153         int i;
8154
8155         pr_debug("RAID conf printout:\n");
8156         if (!conf) {
8157                 pr_debug("(conf==NULL)\n");
8158                 return;
8159         }
8160         pr_debug(" --- level:%d rd:%d wd:%d\n", conf->level,
8161                conf->raid_disks,
8162                conf->raid_disks - conf->mddev->degraded);
8163
8164         rcu_read_lock();
8165         for (i = 0; i < conf->raid_disks; i++) {
8166                 rdev = rcu_dereference(conf->disks[i].rdev);
8167                 if (rdev)
8168                         pr_debug(" disk %d, o:%d, dev:%pg\n",
8169                                i, !test_bit(Faulty, &rdev->flags),
8170                                rdev->bdev);
8171         }
8172         rcu_read_unlock();
8173 }
8174
8175 static int raid5_spare_active(struct mddev *mddev)
8176 {
8177         int i;
8178         struct r5conf *conf = mddev->private;
8179         struct md_rdev *rdev, *replacement;
8180         int count = 0;
8181         unsigned long flags;
8182
8183         for (i = 0; i < conf->raid_disks; i++) {
8184                 rdev = rdev_mdlock_deref(mddev, conf->disks[i].rdev);
8185                 replacement = rdev_mdlock_deref(mddev,
8186                                                 conf->disks[i].replacement);
8187                 if (replacement
8188                     && replacement->recovery_offset == MaxSector
8189                     && !test_bit(Faulty, &replacement->flags)
8190                     && !test_and_set_bit(In_sync, &replacement->flags)) {
8191                         /* Replacement has just become active. */
8192                         if (!rdev
8193                             || !test_and_clear_bit(In_sync, &rdev->flags))
8194                                 count++;
8195                         if (rdev) {
8196                                 /* Replaced device not technically faulty,
8197                                  * but we need to be sure it gets removed
8198                                  * and never re-added.
8199                                  */
8200                                 set_bit(Faulty, &rdev->flags);
8201                                 sysfs_notify_dirent_safe(
8202                                         rdev->sysfs_state);
8203                         }
8204                         sysfs_notify_dirent_safe(replacement->sysfs_state);
8205                 } else if (rdev
8206                     && rdev->recovery_offset == MaxSector
8207                     && !test_bit(Faulty, &rdev->flags)
8208                     && !test_and_set_bit(In_sync, &rdev->flags)) {
8209                         count++;
8210                         sysfs_notify_dirent_safe(rdev->sysfs_state);
8211                 }
8212         }
8213         spin_lock_irqsave(&conf->device_lock, flags);
8214         mddev->degraded = raid5_calc_degraded(conf);
8215         spin_unlock_irqrestore(&conf->device_lock, flags);
8216         print_raid5_conf(conf);
8217         return count;
8218 }
8219
8220 static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
8221 {
8222         struct r5conf *conf = mddev->private;
8223         int err = 0;
8224         int number = rdev->raid_disk;
8225         struct md_rdev __rcu **rdevp;
8226         struct disk_info *p;
8227         struct md_rdev *tmp;
8228
8229         print_raid5_conf(conf);
8230         if (test_bit(Journal, &rdev->flags) && conf->log) {
8231                 /*
8232                  * we can't wait pending write here, as this is called in
8233                  * raid5d, wait will deadlock.
8234                  * neilb: there is no locking about new writes here,
8235                  * so this cannot be safe.
8236                  */
8237                 if (atomic_read(&conf->active_stripes) ||
8238                     atomic_read(&conf->r5c_cached_full_stripes) ||
8239                     atomic_read(&conf->r5c_cached_partial_stripes)) {
8240                         return -EBUSY;
8241                 }
8242                 log_exit(conf);
8243                 return 0;
8244         }
8245         if (unlikely(number >= conf->pool_size))
8246                 return 0;
8247         p = conf->disks + number;
8248         if (rdev == rcu_access_pointer(p->rdev))
8249                 rdevp = &p->rdev;
8250         else if (rdev == rcu_access_pointer(p->replacement))
8251                 rdevp = &p->replacement;
8252         else
8253                 return 0;
8254
8255         if (number >= conf->raid_disks &&
8256             conf->reshape_progress == MaxSector)
8257                 clear_bit(In_sync, &rdev->flags);
8258
8259         if (test_bit(In_sync, &rdev->flags) ||
8260             atomic_read(&rdev->nr_pending)) {
8261                 err = -EBUSY;
8262                 goto abort;
8263         }
8264         /* Only remove non-faulty devices if recovery
8265          * isn't possible.
8266          */
8267         if (!test_bit(Faulty, &rdev->flags) &&
8268             mddev->recovery_disabled != conf->recovery_disabled &&
8269             !has_failed(conf) &&
8270             (!rcu_access_pointer(p->replacement) ||
8271              rcu_access_pointer(p->replacement) == rdev) &&
8272             number < conf->raid_disks) {
8273                 err = -EBUSY;
8274                 goto abort;
8275         }
8276         *rdevp = NULL;
8277         if (!test_bit(RemoveSynchronized, &rdev->flags)) {
8278                 lockdep_assert_held(&mddev->reconfig_mutex);
8279                 synchronize_rcu();
8280                 if (atomic_read(&rdev->nr_pending)) {
8281                         /* lost the race, try later */
8282                         err = -EBUSY;
8283                         rcu_assign_pointer(*rdevp, rdev);
8284                 }
8285         }
8286         if (!err) {
8287                 err = log_modify(conf, rdev, false);
8288                 if (err)
8289                         goto abort;
8290         }
8291
8292         tmp = rcu_access_pointer(p->replacement);
8293         if (tmp) {
8294                 /* We must have just cleared 'rdev' */
8295                 rcu_assign_pointer(p->rdev, tmp);
8296                 clear_bit(Replacement, &tmp->flags);
8297                 smp_mb(); /* Make sure other CPUs may see both as identical
8298                            * but will never see neither - if they are careful
8299                            */
8300                 rcu_assign_pointer(p->replacement, NULL);
8301
8302                 if (!err)
8303                         err = log_modify(conf, tmp, true);
8304         }
8305
8306         clear_bit(WantReplacement, &rdev->flags);
8307 abort:
8308
8309         print_raid5_conf(conf);
8310         return err;
8311 }
8312
8313 static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
8314 {
8315         struct r5conf *conf = mddev->private;
8316         int ret, err = -EEXIST;
8317         int disk;
8318         struct disk_info *p;
8319         struct md_rdev *tmp;
8320         int first = 0;
8321         int last = conf->raid_disks - 1;
8322
8323         if (test_bit(Journal, &rdev->flags)) {
8324                 if (conf->log)
8325                         return -EBUSY;
8326
8327                 rdev->raid_disk = 0;
8328                 /*
8329                  * The array is in readonly mode if journal is missing, so no
8330                  * write requests running. We should be safe
8331                  */
8332                 ret = log_init(conf, rdev, false);
8333                 if (ret)
8334                         return ret;
8335
8336                 ret = r5l_start(conf->log);
8337                 if (ret)
8338                         return ret;
8339
8340                 return 0;
8341         }
8342         if (mddev->recovery_disabled == conf->recovery_disabled)
8343                 return -EBUSY;
8344
8345         if (rdev->saved_raid_disk < 0 && has_failed(conf))
8346                 /* no point adding a device */
8347                 return -EINVAL;
8348
8349         if (rdev->raid_disk >= 0)
8350                 first = last = rdev->raid_disk;
8351
8352         /*
8353          * find the disk ... but prefer rdev->saved_raid_disk
8354          * if possible.
8355          */
8356         if (rdev->saved_raid_disk >= first &&
8357             rdev->saved_raid_disk <= last &&
8358             conf->disks[rdev->saved_raid_disk].rdev == NULL)
8359                 first = rdev->saved_raid_disk;
8360
8361         for (disk = first; disk <= last; disk++) {
8362                 p = conf->disks + disk;
8363                 if (p->rdev == NULL) {
8364                         clear_bit(In_sync, &rdev->flags);
8365                         rdev->raid_disk = disk;
8366                         if (rdev->saved_raid_disk != disk)
8367                                 conf->fullsync = 1;
8368                         rcu_assign_pointer(p->rdev, rdev);
8369
8370                         err = log_modify(conf, rdev, true);
8371
8372                         goto out;
8373                 }
8374         }
8375         for (disk = first; disk <= last; disk++) {
8376                 p = conf->disks + disk;
8377                 tmp = rdev_mdlock_deref(mddev, p->rdev);
8378                 if (test_bit(WantReplacement, &tmp->flags) &&
8379                     mddev->reshape_position == MaxSector &&
8380                     p->replacement == NULL) {
8381                         clear_bit(In_sync, &rdev->flags);
8382                         set_bit(Replacement, &rdev->flags);
8383                         rdev->raid_disk = disk;
8384                         err = 0;
8385                         conf->fullsync = 1;
8386                         rcu_assign_pointer(p->replacement, rdev);
8387                         break;
8388                 }
8389         }
8390 out:
8391         print_raid5_conf(conf);
8392         return err;
8393 }
8394
8395 static int raid5_resize(struct mddev *mddev, sector_t sectors)
8396 {
8397         /* no resync is happening, and there is enough space
8398          * on all devices, so we can resize.
8399          * We need to make sure resync covers any new space.
8400          * If the array is shrinking we should possibly wait until
8401          * any io in the removed space completes, but it hardly seems
8402          * worth it.
8403          */
8404         sector_t newsize;
8405         struct r5conf *conf = mddev->private;
8406
8407         if (raid5_has_log(conf) || raid5_has_ppl(conf))
8408                 return -EINVAL;
8409         sectors &= ~((sector_t)conf->chunk_sectors - 1);
8410         newsize = raid5_size(mddev, sectors, mddev->raid_disks);
8411         if (mddev->external_size &&
8412             mddev->array_sectors > newsize)
8413                 return -EINVAL;
8414         if (mddev->bitmap) {
8415                 int ret = md_bitmap_resize(mddev->bitmap, sectors, 0, 0);
8416                 if (ret)
8417                         return ret;
8418         }
8419         md_set_array_sectors(mddev, newsize);
8420         if (sectors > mddev->dev_sectors &&
8421             mddev->recovery_cp > mddev->dev_sectors) {
8422                 mddev->recovery_cp = mddev->dev_sectors;
8423                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
8424         }
8425         mddev->dev_sectors = sectors;
8426         mddev->resync_max_sectors = sectors;
8427         return 0;
8428 }
8429
8430 static int check_stripe_cache(struct mddev *mddev)
8431 {
8432         /* Can only proceed if there are plenty of stripe_heads.
8433          * We need a minimum of one full stripe,, and for sensible progress
8434          * it is best to have about 4 times that.
8435          * If we require 4 times, then the default 256 4K stripe_heads will
8436          * allow for chunk sizes up to 256K, which is probably OK.
8437          * If the chunk size is greater, user-space should request more
8438          * stripe_heads first.
8439          */
8440         struct r5conf *conf = mddev->private;
8441         if (((mddev->chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4
8442             > conf->min_nr_stripes ||
8443             ((mddev->new_chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4
8444             > conf->min_nr_stripes) {
8445                 pr_warn("md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
8446                         mdname(mddev),
8447                         ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
8448                          / RAID5_STRIPE_SIZE(conf))*4);
8449                 return 0;
8450         }
8451         return 1;
8452 }
8453
8454 static int check_reshape(struct mddev *mddev)
8455 {
8456         struct r5conf *conf = mddev->private;
8457
8458         if (raid5_has_log(conf) || raid5_has_ppl(conf))
8459                 return -EINVAL;
8460         if (mddev->delta_disks == 0 &&
8461             mddev->new_layout == mddev->layout &&
8462             mddev->new_chunk_sectors == mddev->chunk_sectors)
8463                 return 0; /* nothing to do */
8464         if (has_failed(conf))
8465                 return -EINVAL;
8466         if (mddev->delta_disks < 0 && mddev->reshape_position == MaxSector) {
8467                 /* We might be able to shrink, but the devices must
8468                  * be made bigger first.
8469                  * For raid6, 4 is the minimum size.
8470                  * Otherwise 2 is the minimum
8471                  */
8472                 int min = 2;
8473                 if (mddev->level == 6)
8474                         min = 4;
8475                 if (mddev->raid_disks + mddev->delta_disks < min)
8476                         return -EINVAL;
8477         }
8478
8479         if (!check_stripe_cache(mddev))
8480                 return -ENOSPC;
8481
8482         if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
8483             mddev->delta_disks > 0)
8484                 if (resize_chunks(conf,
8485                                   conf->previous_raid_disks
8486                                   + max(0, mddev->delta_disks),
8487                                   max(mddev->new_chunk_sectors,
8488                                       mddev->chunk_sectors)
8489                             ) < 0)
8490                         return -ENOMEM;
8491
8492         if (conf->previous_raid_disks + mddev->delta_disks <= conf->pool_size)
8493                 return 0; /* never bother to shrink */
8494         return resize_stripes(conf, (conf->previous_raid_disks
8495                                      + mddev->delta_disks));
8496 }
8497
8498 static int raid5_start_reshape(struct mddev *mddev)
8499 {
8500         struct r5conf *conf = mddev->private;
8501         struct md_rdev *rdev;
8502         int spares = 0;
8503         int i;
8504         unsigned long flags;
8505
8506         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
8507                 return -EBUSY;
8508
8509         if (!check_stripe_cache(mddev))
8510                 return -ENOSPC;
8511
8512         if (has_failed(conf))
8513                 return -EINVAL;
8514
8515         /* raid5 can't handle concurrent reshape and recovery */
8516         if (mddev->recovery_cp < MaxSector)
8517                 return -EBUSY;
8518         for (i = 0; i < conf->raid_disks; i++)
8519                 if (rdev_mdlock_deref(mddev, conf->disks[i].replacement))
8520                         return -EBUSY;
8521
8522         rdev_for_each(rdev, mddev) {
8523                 if (!test_bit(In_sync, &rdev->flags)
8524                     && !test_bit(Faulty, &rdev->flags))
8525                         spares++;
8526         }
8527
8528         if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
8529                 /* Not enough devices even to make a degraded array
8530                  * of that size
8531                  */
8532                 return -EINVAL;
8533
8534         /* Refuse to reduce size of the array.  Any reductions in
8535          * array size must be through explicit setting of array_size
8536          * attribute.
8537          */
8538         if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
8539             < mddev->array_sectors) {
8540                 pr_warn("md/raid:%s: array size must be reduced before number of disks\n",
8541                         mdname(mddev));
8542                 return -EINVAL;
8543         }
8544
8545         atomic_set(&conf->reshape_stripes, 0);
8546         spin_lock_irq(&conf->device_lock);
8547         write_seqcount_begin(&conf->gen_lock);
8548         conf->previous_raid_disks = conf->raid_disks;
8549         conf->raid_disks += mddev->delta_disks;
8550         conf->prev_chunk_sectors = conf->chunk_sectors;
8551         conf->chunk_sectors = mddev->new_chunk_sectors;
8552         conf->prev_algo = conf->algorithm;
8553         conf->algorithm = mddev->new_layout;
8554         conf->generation++;
8555         /* Code that selects data_offset needs to see the generation update
8556          * if reshape_progress has been set - so a memory barrier needed.
8557          */
8558         smp_mb();
8559         if (mddev->reshape_backwards)
8560                 conf->reshape_progress = raid5_size(mddev, 0, 0);
8561         else
8562                 conf->reshape_progress = 0;
8563         conf->reshape_safe = conf->reshape_progress;
8564         write_seqcount_end(&conf->gen_lock);
8565         spin_unlock_irq(&conf->device_lock);
8566
8567         /* Now make sure any requests that proceeded on the assumption
8568          * the reshape wasn't running - like Discard or Read - have
8569          * completed.
8570          */
8571         mddev_suspend(mddev);
8572         mddev_resume(mddev);
8573
8574         /* Add some new drives, as many as will fit.
8575          * We know there are enough to make the newly sized array work.
8576          * Don't add devices if we are reducing the number of
8577          * devices in the array.  This is because it is not possible
8578          * to correctly record the "partially reconstructed" state of
8579          * such devices during the reshape and confusion could result.
8580          */
8581         if (mddev->delta_disks >= 0) {
8582                 rdev_for_each(rdev, mddev)
8583                         if (rdev->raid_disk < 0 &&
8584                             !test_bit(Faulty, &rdev->flags)) {
8585                                 if (raid5_add_disk(mddev, rdev) == 0) {
8586                                         if (rdev->raid_disk
8587                                             >= conf->previous_raid_disks)
8588                                                 set_bit(In_sync, &rdev->flags);
8589                                         else
8590                                                 rdev->recovery_offset = 0;
8591
8592                                         /* Failure here is OK */
8593                                         sysfs_link_rdev(mddev, rdev);
8594                                 }
8595                         } else if (rdev->raid_disk >= conf->previous_raid_disks
8596                                    && !test_bit(Faulty, &rdev->flags)) {
8597                                 /* This is a spare that was manually added */
8598                                 set_bit(In_sync, &rdev->flags);
8599                         }
8600
8601                 /* When a reshape changes the number of devices,
8602                  * ->degraded is measured against the larger of the
8603                  * pre and post number of devices.
8604                  */
8605                 spin_lock_irqsave(&conf->device_lock, flags);
8606                 mddev->degraded = raid5_calc_degraded(conf);
8607                 spin_unlock_irqrestore(&conf->device_lock, flags);
8608         }
8609         mddev->raid_disks = conf->raid_disks;
8610         mddev->reshape_position = conf->reshape_progress;
8611         set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8612
8613         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
8614         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
8615         clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
8616         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
8617         set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
8618         rcu_assign_pointer(mddev->sync_thread,
8619                            md_register_thread(md_do_sync, mddev, "reshape"));
8620         if (!mddev->sync_thread) {
8621                 mddev->recovery = 0;
8622                 spin_lock_irq(&conf->device_lock);
8623                 write_seqcount_begin(&conf->gen_lock);
8624                 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
8625                 mddev->new_chunk_sectors =
8626                         conf->chunk_sectors = conf->prev_chunk_sectors;
8627                 mddev->new_layout = conf->algorithm = conf->prev_algo;
8628                 rdev_for_each(rdev, mddev)
8629                         rdev->new_data_offset = rdev->data_offset;
8630                 smp_wmb();
8631                 conf->generation --;
8632                 conf->reshape_progress = MaxSector;
8633                 mddev->reshape_position = MaxSector;
8634                 write_seqcount_end(&conf->gen_lock);
8635                 spin_unlock_irq(&conf->device_lock);
8636                 return -EAGAIN;
8637         }
8638         conf->reshape_checkpoint = jiffies;
8639         md_wakeup_thread(mddev->sync_thread);
8640         md_new_event();
8641         return 0;
8642 }
8643
8644 /* This is called from the reshape thread and should make any
8645  * changes needed in 'conf'
8646  */
8647 static void end_reshape(struct r5conf *conf)
8648 {
8649
8650         if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
8651                 struct md_rdev *rdev;
8652
8653                 spin_lock_irq(&conf->device_lock);
8654                 conf->previous_raid_disks = conf->raid_disks;
8655                 md_finish_reshape(conf->mddev);
8656                 smp_wmb();
8657                 conf->reshape_progress = MaxSector;
8658                 conf->mddev->reshape_position = MaxSector;
8659                 rdev_for_each(rdev, conf->mddev)
8660                         if (rdev->raid_disk >= 0 &&
8661                             !test_bit(Journal, &rdev->flags) &&
8662                             !test_bit(In_sync, &rdev->flags))
8663                                 rdev->recovery_offset = MaxSector;
8664                 spin_unlock_irq(&conf->device_lock);
8665                 wake_up(&conf->wait_for_overlap);
8666
8667                 if (conf->mddev->queue)
8668                         raid5_set_io_opt(conf);
8669         }
8670 }
8671
8672 /* This is called from the raid5d thread with mddev_lock held.
8673  * It makes config changes to the device.
8674  */
8675 static void raid5_finish_reshape(struct mddev *mddev)
8676 {
8677         struct r5conf *conf = mddev->private;
8678         struct md_rdev *rdev;
8679
8680         if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
8681
8682                 if (mddev->delta_disks <= 0) {
8683                         int d;
8684                         spin_lock_irq(&conf->device_lock);
8685                         mddev->degraded = raid5_calc_degraded(conf);
8686                         spin_unlock_irq(&conf->device_lock);
8687                         for (d = conf->raid_disks ;
8688                              d < conf->raid_disks - mddev->delta_disks;
8689                              d++) {
8690                                 rdev = rdev_mdlock_deref(mddev,
8691                                                          conf->disks[d].rdev);
8692                                 if (rdev)
8693                                         clear_bit(In_sync, &rdev->flags);
8694                                 rdev = rdev_mdlock_deref(mddev,
8695                                                 conf->disks[d].replacement);
8696                                 if (rdev)
8697                                         clear_bit(In_sync, &rdev->flags);
8698                         }
8699                 }
8700                 mddev->layout = conf->algorithm;
8701                 mddev->chunk_sectors = conf->chunk_sectors;
8702                 mddev->reshape_position = MaxSector;
8703                 mddev->delta_disks = 0;
8704                 mddev->reshape_backwards = 0;
8705         }
8706 }
8707
8708 static void raid5_quiesce(struct mddev *mddev, int quiesce)
8709 {
8710         struct r5conf *conf = mddev->private;
8711
8712         if (quiesce) {
8713                 /* stop all writes */
8714                 lock_all_device_hash_locks_irq(conf);
8715                 /* '2' tells resync/reshape to pause so that all
8716                  * active stripes can drain
8717                  */
8718                 r5c_flush_cache(conf, INT_MAX);
8719                 /* need a memory barrier to make sure read_one_chunk() sees
8720                  * quiesce started and reverts to slow (locked) path.
8721                  */
8722                 smp_store_release(&conf->quiesce, 2);
8723                 wait_event_cmd(conf->wait_for_quiescent,
8724                                     atomic_read(&conf->active_stripes) == 0 &&
8725                                     atomic_read(&conf->active_aligned_reads) == 0,
8726                                     unlock_all_device_hash_locks_irq(conf),
8727                                     lock_all_device_hash_locks_irq(conf));
8728                 conf->quiesce = 1;
8729                 unlock_all_device_hash_locks_irq(conf);
8730                 /* allow reshape to continue */
8731                 wake_up(&conf->wait_for_overlap);
8732         } else {
8733                 /* re-enable writes */
8734                 lock_all_device_hash_locks_irq(conf);
8735                 conf->quiesce = 0;
8736                 wake_up(&conf->wait_for_quiescent);
8737                 wake_up(&conf->wait_for_overlap);
8738                 unlock_all_device_hash_locks_irq(conf);
8739         }
8740         log_quiesce(conf, quiesce);
8741 }
8742
8743 static void *raid45_takeover_raid0(struct mddev *mddev, int level)
8744 {
8745         struct r0conf *raid0_conf = mddev->private;
8746         sector_t sectors;
8747
8748         /* for raid0 takeover only one zone is supported */
8749         if (raid0_conf->nr_strip_zones > 1) {
8750                 pr_warn("md/raid:%s: cannot takeover raid0 with more than one zone.\n",
8751                         mdname(mddev));
8752                 return ERR_PTR(-EINVAL);
8753         }
8754
8755         sectors = raid0_conf->strip_zone[0].zone_end;
8756         sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
8757         mddev->dev_sectors = sectors;
8758         mddev->new_level = level;
8759         mddev->new_layout = ALGORITHM_PARITY_N;
8760         mddev->new_chunk_sectors = mddev->chunk_sectors;
8761         mddev->raid_disks += 1;
8762         mddev->delta_disks = 1;
8763         /* make sure it will be not marked as dirty */
8764         mddev->recovery_cp = MaxSector;
8765
8766         return setup_conf(mddev);
8767 }
8768
8769 static void *raid5_takeover_raid1(struct mddev *mddev)
8770 {
8771         int chunksect;
8772         void *ret;
8773
8774         if (mddev->raid_disks != 2 ||
8775             mddev->degraded > 1)
8776                 return ERR_PTR(-EINVAL);
8777
8778         /* Should check if there are write-behind devices? */
8779
8780         chunksect = 64*2; /* 64K by default */
8781
8782         /* The array must be an exact multiple of chunksize */
8783         while (chunksect && (mddev->array_sectors & (chunksect-1)))
8784                 chunksect >>= 1;
8785
8786         if ((chunksect<<9) < RAID5_STRIPE_SIZE((struct r5conf *)mddev->private))
8787                 /* array size does not allow a suitable chunk size */
8788                 return ERR_PTR(-EINVAL);
8789
8790         mddev->new_level = 5;
8791         mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
8792         mddev->new_chunk_sectors = chunksect;
8793
8794         ret = setup_conf(mddev);
8795         if (!IS_ERR(ret))
8796                 mddev_clear_unsupported_flags(mddev,
8797                         UNSUPPORTED_MDDEV_FLAGS);
8798         return ret;
8799 }
8800
8801 static void *raid5_takeover_raid6(struct mddev *mddev)
8802 {
8803         int new_layout;
8804
8805         switch (mddev->layout) {
8806         case ALGORITHM_LEFT_ASYMMETRIC_6:
8807                 new_layout = ALGORITHM_LEFT_ASYMMETRIC;
8808                 break;
8809         case ALGORITHM_RIGHT_ASYMMETRIC_6:
8810                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
8811                 break;
8812         case ALGORITHM_LEFT_SYMMETRIC_6:
8813                 new_layout = ALGORITHM_LEFT_SYMMETRIC;
8814                 break;
8815         case ALGORITHM_RIGHT_SYMMETRIC_6:
8816                 new_layout = ALGORITHM_RIGHT_SYMMETRIC;
8817                 break;
8818         case ALGORITHM_PARITY_0_6:
8819                 new_layout = ALGORITHM_PARITY_0;
8820                 break;
8821         case ALGORITHM_PARITY_N:
8822                 new_layout = ALGORITHM_PARITY_N;
8823                 break;
8824         default:
8825                 return ERR_PTR(-EINVAL);
8826         }
8827         mddev->new_level = 5;
8828         mddev->new_layout = new_layout;
8829         mddev->delta_disks = -1;
8830         mddev->raid_disks -= 1;
8831         return setup_conf(mddev);
8832 }
8833
8834 static int raid5_check_reshape(struct mddev *mddev)
8835 {
8836         /* For a 2-drive array, the layout and chunk size can be changed
8837          * immediately as not restriping is needed.
8838          * For larger arrays we record the new value - after validation
8839          * to be used by a reshape pass.
8840          */
8841         struct r5conf *conf = mddev->private;
8842         int new_chunk = mddev->new_chunk_sectors;
8843
8844         if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
8845                 return -EINVAL;
8846         if (new_chunk > 0) {
8847                 if (!is_power_of_2(new_chunk))
8848                         return -EINVAL;
8849                 if (new_chunk < (PAGE_SIZE>>9))
8850                         return -EINVAL;
8851                 if (mddev->array_sectors & (new_chunk-1))
8852                         /* not factor of array size */
8853                         return -EINVAL;
8854         }
8855
8856         /* They look valid */
8857
8858         if (mddev->raid_disks == 2) {
8859                 /* can make the change immediately */
8860                 if (mddev->new_layout >= 0) {
8861                         conf->algorithm = mddev->new_layout;
8862                         mddev->layout = mddev->new_layout;
8863                 }
8864                 if (new_chunk > 0) {
8865                         conf->chunk_sectors = new_chunk ;
8866                         mddev->chunk_sectors = new_chunk;
8867                 }
8868                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8869                 md_wakeup_thread(mddev->thread);
8870         }
8871         return check_reshape(mddev);
8872 }
8873
8874 static int raid6_check_reshape(struct mddev *mddev)
8875 {
8876         int new_chunk = mddev->new_chunk_sectors;
8877
8878         if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
8879                 return -EINVAL;
8880         if (new_chunk > 0) {
8881                 if (!is_power_of_2(new_chunk))
8882                         return -EINVAL;
8883                 if (new_chunk < (PAGE_SIZE >> 9))
8884                         return -EINVAL;
8885                 if (mddev->array_sectors & (new_chunk-1))
8886                         /* not factor of array size */
8887                         return -EINVAL;
8888         }
8889
8890         /* They look valid */
8891         return check_reshape(mddev);
8892 }
8893
8894 static void *raid5_takeover(struct mddev *mddev)
8895 {
8896         /* raid5 can take over:
8897          *  raid0 - if there is only one strip zone - make it a raid4 layout
8898          *  raid1 - if there are two drives.  We need to know the chunk size
8899          *  raid4 - trivial - just use a raid4 layout.
8900          *  raid6 - Providing it is a *_6 layout
8901          */
8902         if (mddev->level == 0)
8903                 return raid45_takeover_raid0(mddev, 5);
8904         if (mddev->level == 1)
8905                 return raid5_takeover_raid1(mddev);
8906         if (mddev->level == 4) {
8907                 mddev->new_layout = ALGORITHM_PARITY_N;
8908                 mddev->new_level = 5;
8909                 return setup_conf(mddev);
8910         }
8911         if (mddev->level == 6)
8912                 return raid5_takeover_raid6(mddev);
8913
8914         return ERR_PTR(-EINVAL);
8915 }
8916
8917 static void *raid4_takeover(struct mddev *mddev)
8918 {
8919         /* raid4 can take over:
8920          *  raid0 - if there is only one strip zone
8921          *  raid5 - if layout is right
8922          */
8923         if (mddev->level == 0)
8924                 return raid45_takeover_raid0(mddev, 4);
8925         if (mddev->level == 5 &&
8926             mddev->layout == ALGORITHM_PARITY_N) {
8927                 mddev->new_layout = 0;
8928                 mddev->new_level = 4;
8929                 return setup_conf(mddev);
8930         }
8931         return ERR_PTR(-EINVAL);
8932 }
8933
8934 static struct md_personality raid5_personality;
8935
8936 static void *raid6_takeover(struct mddev *mddev)
8937 {
8938         /* Currently can only take over a raid5.  We map the
8939          * personality to an equivalent raid6 personality
8940          * with the Q block at the end.
8941          */
8942         int new_layout;
8943
8944         if (mddev->pers != &raid5_personality)
8945                 return ERR_PTR(-EINVAL);
8946         if (mddev->degraded > 1)
8947                 return ERR_PTR(-EINVAL);
8948         if (mddev->raid_disks > 253)
8949                 return ERR_PTR(-EINVAL);
8950         if (mddev->raid_disks < 3)
8951                 return ERR_PTR(-EINVAL);
8952
8953         switch (mddev->layout) {
8954         case ALGORITHM_LEFT_ASYMMETRIC:
8955                 new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
8956                 break;
8957         case ALGORITHM_RIGHT_ASYMMETRIC:
8958                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
8959                 break;
8960         case ALGORITHM_LEFT_SYMMETRIC:
8961                 new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
8962                 break;
8963         case ALGORITHM_RIGHT_SYMMETRIC:
8964                 new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
8965                 break;
8966         case ALGORITHM_PARITY_0:
8967                 new_layout = ALGORITHM_PARITY_0_6;
8968                 break;
8969         case ALGORITHM_PARITY_N:
8970                 new_layout = ALGORITHM_PARITY_N;
8971                 break;
8972         default:
8973                 return ERR_PTR(-EINVAL);
8974         }
8975         mddev->new_level = 6;
8976         mddev->new_layout = new_layout;
8977         mddev->delta_disks = 1;
8978         mddev->raid_disks += 1;
8979         return setup_conf(mddev);
8980 }
8981
8982 static int raid5_change_consistency_policy(struct mddev *mddev, const char *buf)
8983 {
8984         struct r5conf *conf;
8985         int err;
8986
8987         err = mddev_lock(mddev);
8988         if (err)
8989                 return err;
8990         conf = mddev->private;
8991         if (!conf) {
8992                 mddev_unlock(mddev);
8993                 return -ENODEV;
8994         }
8995
8996         if (strncmp(buf, "ppl", 3) == 0) {
8997                 /* ppl only works with RAID 5 */
8998                 if (!raid5_has_ppl(conf) && conf->level == 5) {
8999                         err = log_init(conf, NULL, true);
9000                         if (!err) {
9001                                 err = resize_stripes(conf, conf->pool_size);
9002                                 if (err) {
9003                                         mddev_suspend(mddev);
9004                                         log_exit(conf);
9005                                         mddev_resume(mddev);
9006                                 }
9007                         }
9008                 } else
9009                         err = -EINVAL;
9010         } else if (strncmp(buf, "resync", 6) == 0) {
9011                 if (raid5_has_ppl(conf)) {
9012                         mddev_suspend(mddev);
9013                         log_exit(conf);
9014                         mddev_resume(mddev);
9015                         err = resize_stripes(conf, conf->pool_size);
9016                 } else if (test_bit(MD_HAS_JOURNAL, &conf->mddev->flags) &&
9017                            r5l_log_disk_error(conf)) {
9018                         bool journal_dev_exists = false;
9019                         struct md_rdev *rdev;
9020
9021                         rdev_for_each(rdev, mddev)
9022                                 if (test_bit(Journal, &rdev->flags)) {
9023                                         journal_dev_exists = true;
9024                                         break;
9025                                 }
9026
9027                         if (!journal_dev_exists) {
9028                                 mddev_suspend(mddev);
9029                                 clear_bit(MD_HAS_JOURNAL, &mddev->flags);
9030                                 mddev_resume(mddev);
9031                         } else  /* need remove journal device first */
9032                                 err = -EBUSY;
9033                 } else
9034                         err = -EINVAL;
9035         } else {
9036                 err = -EINVAL;
9037         }
9038
9039         if (!err)
9040                 md_update_sb(mddev, 1);
9041
9042         mddev_unlock(mddev);
9043
9044         return err;
9045 }
9046
9047 static int raid5_start(struct mddev *mddev)
9048 {
9049         struct r5conf *conf = mddev->private;
9050
9051         return r5l_start(conf->log);
9052 }
9053
9054 static void raid5_prepare_suspend(struct mddev *mddev)
9055 {
9056         struct r5conf *conf = mddev->private;
9057
9058         wait_event(mddev->sb_wait, !reshape_inprogress(mddev) ||
9059                                     percpu_ref_is_zero(&mddev->active_io));
9060         if (percpu_ref_is_zero(&mddev->active_io))
9061                 return;
9062
9063         /*
9064          * Reshape is not in progress, and array is suspended, io that is
9065          * waiting for reshpape can never be done.
9066          */
9067         wake_up(&conf->wait_for_overlap);
9068 }
9069
9070 static struct md_personality raid6_personality =
9071 {
9072         .name           = "raid6",
9073         .level          = 6,
9074         .owner          = THIS_MODULE,
9075         .make_request   = raid5_make_request,
9076         .run            = raid5_run,
9077         .start          = raid5_start,
9078         .free           = raid5_free,
9079         .status         = raid5_status,
9080         .error_handler  = raid5_error,
9081         .hot_add_disk   = raid5_add_disk,
9082         .hot_remove_disk= raid5_remove_disk,
9083         .spare_active   = raid5_spare_active,
9084         .sync_request   = raid5_sync_request,
9085         .resize         = raid5_resize,
9086         .size           = raid5_size,
9087         .check_reshape  = raid6_check_reshape,
9088         .start_reshape  = raid5_start_reshape,
9089         .finish_reshape = raid5_finish_reshape,
9090         .prepare_suspend = raid5_prepare_suspend,
9091         .quiesce        = raid5_quiesce,
9092         .takeover       = raid6_takeover,
9093         .change_consistency_policy = raid5_change_consistency_policy,
9094 };
9095 static struct md_personality raid5_personality =
9096 {
9097         .name           = "raid5",
9098         .level          = 5,
9099         .owner          = THIS_MODULE,
9100         .make_request   = raid5_make_request,
9101         .run            = raid5_run,
9102         .start          = raid5_start,
9103         .free           = raid5_free,
9104         .status         = raid5_status,
9105         .error_handler  = raid5_error,
9106         .hot_add_disk   = raid5_add_disk,
9107         .hot_remove_disk= raid5_remove_disk,
9108         .spare_active   = raid5_spare_active,
9109         .sync_request   = raid5_sync_request,
9110         .resize         = raid5_resize,
9111         .size           = raid5_size,
9112         .check_reshape  = raid5_check_reshape,
9113         .start_reshape  = raid5_start_reshape,
9114         .finish_reshape = raid5_finish_reshape,
9115         .prepare_suspend = raid5_prepare_suspend,
9116         .quiesce        = raid5_quiesce,
9117         .takeover       = raid5_takeover,
9118         .change_consistency_policy = raid5_change_consistency_policy,
9119 };
9120
9121 static struct md_personality raid4_personality =
9122 {
9123         .name           = "raid4",
9124         .level          = 4,
9125         .owner          = THIS_MODULE,
9126         .make_request   = raid5_make_request,
9127         .run            = raid5_run,
9128         .start          = raid5_start,
9129         .free           = raid5_free,
9130         .status         = raid5_status,
9131         .error_handler  = raid5_error,
9132         .hot_add_disk   = raid5_add_disk,
9133         .hot_remove_disk= raid5_remove_disk,
9134         .spare_active   = raid5_spare_active,
9135         .sync_request   = raid5_sync_request,
9136         .resize         = raid5_resize,
9137         .size           = raid5_size,
9138         .check_reshape  = raid5_check_reshape,
9139         .start_reshape  = raid5_start_reshape,
9140         .finish_reshape = raid5_finish_reshape,
9141         .prepare_suspend = raid5_prepare_suspend,
9142         .quiesce        = raid5_quiesce,
9143         .takeover       = raid4_takeover,
9144         .change_consistency_policy = raid5_change_consistency_policy,
9145 };
9146
9147 static int __init raid5_init(void)
9148 {
9149         int ret;
9150
9151         raid5_wq = alloc_workqueue("raid5wq",
9152                 WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE|WQ_SYSFS, 0);
9153         if (!raid5_wq)
9154                 return -ENOMEM;
9155
9156         ret = cpuhp_setup_state_multi(CPUHP_MD_RAID5_PREPARE,
9157                                       "md/raid5:prepare",
9158                                       raid456_cpu_up_prepare,
9159                                       raid456_cpu_dead);
9160         if (ret) {
9161                 destroy_workqueue(raid5_wq);
9162                 return ret;
9163         }
9164         register_md_personality(&raid6_personality);
9165         register_md_personality(&raid5_personality);
9166         register_md_personality(&raid4_personality);
9167         return 0;
9168 }
9169
9170 static void raid5_exit(void)
9171 {
9172         unregister_md_personality(&raid6_personality);
9173         unregister_md_personality(&raid5_personality);
9174         unregister_md_personality(&raid4_personality);
9175         cpuhp_remove_multi_state(CPUHP_MD_RAID5_PREPARE);
9176         destroy_workqueue(raid5_wq);
9177 }
9178
9179 module_init(raid5_init);
9180 module_exit(raid5_exit);
9181 MODULE_LICENSE("GPL");
9182 MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
9183 MODULE_ALIAS("md-personality-4"); /* RAID5 */
9184 MODULE_ALIAS("md-raid5");
9185 MODULE_ALIAS("md-raid4");
9186 MODULE_ALIAS("md-level-5");
9187 MODULE_ALIAS("md-level-4");
9188 MODULE_ALIAS("md-personality-8"); /* RAID6 */
9189 MODULE_ALIAS("md-raid6");
9190 MODULE_ALIAS("md-level-6");
9191
9192 /* This used to be two separate modules, they were: */
9193 MODULE_ALIAS("raid5");
9194 MODULE_ALIAS("raid6");