drivers/md/raid5.c

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