drivers/md/raid5.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * raid5.c : Multiple Devices driver for Linux
   4  *         Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
   5  *         Copyright (C) 1999, 2000 Ingo Molnar
   6  *         Copyright (C) 2002, 2003 H. Peter Anvin
   7  *
   8  * RAID-4/5/6 management functions.
   9  * Thanks to Penguin Computing for making the RAID-6 development possible
  10  * by donating a test server!
  11  */
  12
  13 /*
  14  * BITMAP UNPLUGGING:
  15  *
  16  * The sequencing for updating the bitmap reliably is a little
  17  * subtle (and I got it wrong the first time) so it deserves some
  18  * explanation.
  19  *
  20  * We group bitmap updates into batches.  Each batch has a number.
  21  * We may write out several batches at once, but that isn't very important.
  22  * conf->seq_write is the number of the last batch successfully written.
  23  * conf->seq_flush is the number of the last batch that was closed to
  24  *    new additions.
  25  * When we discover that we will need to write to any block in a stripe
  26  * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
  27  * the number of the batch it will be in. This is seq_flush+1.
  28  * When we are ready to do a write, if that batch hasn't been written yet,
  29  *   we plug the array and queue the stripe for later.
  30  * When an unplug happens, we increment bm_flush, thus closing the current
  31  *   batch.
  32  * When we notice that bm_flush > bm_write, we write out all pending updates
  33  * to the bitmap, and advance bm_write to where bm_flush was.
  34  * This may occasionally write a bit out twice, but is sure never to
  35  * miss any bits.
  36  */
  37
  38 #include <linux/blkdev.h>
  39 #include <linux/delay.h>
  40 #include <linux/kthread.h>
  41 #include <linux/raid/pq.h>
  42 #include <linux/async_tx.h>
  43 #include <linux/module.h>
  44 #include <linux/async.h>
  45 #include <linux/seq_file.h>
  46 #include <linux/cpu.h>
  47 #include <linux/slab.h>
  48 #include <linux/ratelimit.h>
  49 #include <linux/nodemask.h>
  50
  51 #include <trace/events/block.h>
  52 #include <linux/list_sort.h>
  53
  54 #include "md.h"
  55 #include "raid5.h"
  56 #include "raid0.h"
  57 #include "md-bitmap.h"
  58 #include "raid5-log.h"
  59
  60 #define UNSUPPORTED_MDDEV_FLAGS (1L << MD_FAILFAST_SUPPORTED)
  61
  62 #define cpu_to_group(cpu) cpu_to_node(cpu)
  63 #define ANY_GROUP NUMA_NO_NODE
  64
  65 #define RAID5_MAX_REQ_STRIPES 256
  66
  67 static bool devices_handle_discard_safely = false;
  68 module_param(devices_handle_discard_safely, bool, 0644);
  69 MODULE_PARM_DESC(devices_handle_discard_safely,
  70                  "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
  71 static struct workqueue_struct *raid5_wq;
  72
  73 static void raid5_quiesce(struct mddev *mddev, int quiesce);
  74
  75 static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
  76 {
  77         int hash = (sect >> RAID5_STRIPE_SHIFT(conf)) & HASH_MASK;
  78         return &conf->stripe_hashtbl[hash];
  79 }
  80
  81 static inline int stripe_hash_locks_hash(struct r5conf *conf, sector_t sect)
  82 {
  83         return (sect >> RAID5_STRIPE_SHIFT(conf)) & STRIPE_HASH_LOCKS_MASK;
  84 }
  85
  86 static inline void lock_device_hash_lock(struct r5conf *conf, int hash)
  87         __acquires(&conf->device_lock)
  88 {
  89         spin_lock_irq(conf->hash_locks + hash);
  90         spin_lock(&conf->device_lock);
  91 }
  92
  93 static inline void unlock_device_hash_lock(struct r5conf *conf, int hash)
  94         __releases(&conf->device_lock)
  95 {
  96         spin_unlock(&conf->device_lock);
  97         spin_unlock_irq(conf->hash_locks + hash);
  98 }
  99
 100 static inline void lock_all_device_hash_locks_irq(struct r5conf *conf)
 101         __acquires(&conf->device_lock)
 102 {
 103         int i;
 104         spin_lock_irq(conf->hash_locks);
 105         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
 106                 spin_lock_nest_lock(conf->hash_locks + i, conf->hash_locks);
 107         spin_lock(&conf->device_lock);
 108 }
 109
 110 static inline void unlock_all_device_hash_locks_irq(struct r5conf *conf)
 111         __releases(&conf->device_lock)
 112 {
 113         int i;
 114         spin_unlock(&conf->device_lock);
 115         for (i = NR_STRIPE_HASH_LOCKS - 1; i; i--)
 116                 spin_unlock(conf->hash_locks + i);
 117         spin_unlock_irq(conf->hash_locks);
 118 }
 119
 120 /* Find first data disk in a raid6 stripe */
 121 static inline int raid6_d0(struct stripe_head *sh)
 122 {
 123         if (sh->ddf_layout)
 124                 /* ddf always start from first device */
 125                 return 0;
 126         /* md starts just after Q block */
 127         if (sh->qd_idx == sh->disks - 1)
 128                 return 0;
 129         else
 130                 return sh->qd_idx + 1;
 131 }
 132 static inline int raid6_next_disk(int disk, int raid_disks)
 133 {
 134         disk++;
 135         return (disk < raid_disks) ? disk : 0;
 136 }
 137
 138 /* When walking through the disks in a raid5, starting at raid6_d0,
 139  * We need to map each disk to a 'slot', where the data disks are slot
 140  * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
 141  * is raid_disks-1.  This help does that mapping.
 142  */
 143 static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
 144                              int *count, int syndrome_disks)
 145 {
 146         int slot = *count;
 147
 148         if (sh->ddf_layout)
 149                 (*count)++;
 150         if (idx == sh->pd_idx)
 151                 return syndrome_disks;
 152         if (idx == sh->qd_idx)
 153                 return syndrome_disks + 1;
 154         if (!sh->ddf_layout)
 155                 (*count)++;
 156         return slot;
 157 }
 158
 159 static void print_raid5_conf (struct r5conf *conf);
 160
 161 static int stripe_operations_active(struct stripe_head *sh)
 162 {
 163         return sh->check_state || sh->reconstruct_state ||
 164                test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
 165                test_bit(STRIPE_COMPUTE_RUN, &sh->state);
 166 }
 167
 168 static bool stripe_is_lowprio(struct stripe_head *sh)
 169 {
 170         return (test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) ||
 171                 test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) &&
 172                !test_bit(STRIPE_R5C_CACHING, &sh->state);
 173 }
 174
 175 static void raid5_wakeup_stripe_thread(struct stripe_head *sh)
 176         __must_hold(&sh->raid_conf->device_lock)
 177 {
 178         struct r5conf *conf = sh->raid_conf;
 179         struct r5worker_group *group;
 180         int thread_cnt;
 181         int i, cpu = sh->cpu;
 182
 183         if (!cpu_online(cpu)) {
 184                 cpu = cpumask_any(cpu_online_mask);
 185                 sh->cpu = cpu;
 186         }
 187
 188         if (list_empty(&sh->lru)) {
 189                 struct r5worker_group *group;
 190                 group = conf->worker_groups + cpu_to_group(cpu);
 191                 if (stripe_is_lowprio(sh))
 192                         list_add_tail(&sh->lru, &group->loprio_list);
 193                 else
 194                         list_add_tail(&sh->lru, &group->handle_list);
 195                 group->stripes_cnt++;
 196                 sh->group = group;
 197         }
 198
 199         if (conf->worker_cnt_per_group == 0) {
 200                 md_wakeup_thread(conf->mddev->thread);
 201                 return;
 202         }
 203
 204         group = conf->worker_groups + cpu_to_group(sh->cpu);
 205
 206         group->workers[0].working = true;
 207         /* at least one worker should run to avoid race */
 208         queue_work_on(sh->cpu, raid5_wq, &group->workers[0].work);
 209
 210         thread_cnt = group->stripes_cnt / MAX_STRIPE_BATCH - 1;
 211         /* wakeup more workers */
 212         for (i = 1; i < conf->worker_cnt_per_group && thread_cnt > 0; i++) {
 213                 if (group->workers[i].working == false) {
 214                         group->workers[i].working = true;
 215                         queue_work_on(sh->cpu, raid5_wq,
 216                                       &group->workers[i].work);
 217                         thread_cnt--;
 218                 }
 219         }
 220 }
 221
 222 static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh,
 223                               struct list_head *temp_inactive_list)
 224         __must_hold(&conf->device_lock)
 225 {
 226         int i;
 227         int injournal = 0;      /* number of date pages with R5_InJournal */
 228
 229         BUG_ON(!list_empty(&sh->lru));
 230         BUG_ON(atomic_read(&conf->active_stripes)==0);
 231
 232         if (r5c_is_writeback(conf->log))
 233                 for (i = sh->disks; i--; )
 234                         if (test_bit(R5_InJournal, &sh->dev[i].flags))
 235                                 injournal++;
 236         /*
 237          * In the following cases, the stripe cannot be released to cached
 238          * lists. Therefore, we make the stripe write out and set
 239          * STRIPE_HANDLE:
 240          *   1. when quiesce in r5c write back;
 241          *   2. when resync is requested fot the stripe.
 242          */
 243         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) ||
 244             (conf->quiesce && r5c_is_writeback(conf->log) &&
 245              !test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0)) {
 246                 if (test_bit(STRIPE_R5C_CACHING, &sh->state))
 247                         r5c_make_stripe_write_out(sh);
 248                 set_bit(STRIPE_HANDLE, &sh->state);
 249         }
 250
 251         if (test_bit(STRIPE_HANDLE, &sh->state)) {
 252                 if (test_bit(STRIPE_DELAYED, &sh->state) &&
 253                     !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 254                         list_add_tail(&sh->lru, &conf->delayed_list);
 255                 else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
 256                            sh->bm_seq - conf->seq_write > 0)
 257                         list_add_tail(&sh->lru, &conf->bitmap_list);
 258                 else {
 259                         clear_bit(STRIPE_DELAYED, &sh->state);
 260                         clear_bit(STRIPE_BIT_DELAY, &sh->state);
 261                         if (conf->worker_cnt_per_group == 0) {
 262                                 if (stripe_is_lowprio(sh))
 263                                         list_add_tail(&sh->lru,
 264                                                         &conf->loprio_list);
 265                                 else
 266                                         list_add_tail(&sh->lru,
 267                                                         &conf->handle_list);
 268                         } else {
 269                                 raid5_wakeup_stripe_thread(sh);
 270                                 return;
 271                         }
 272                 }
 273                 md_wakeup_thread(conf->mddev->thread);
 274         } else {
 275                 BUG_ON(stripe_operations_active(sh));
 276                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 277                         if (atomic_dec_return(&conf->preread_active_stripes)
 278                             < IO_THRESHOLD)
 279                                 md_wakeup_thread(conf->mddev->thread);
 280                 atomic_dec(&conf->active_stripes);
 281                 if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
 282                         if (!r5c_is_writeback(conf->log))
 283                                 list_add_tail(&sh->lru, temp_inactive_list);
 284                         else {
 285                                 WARN_ON(test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags));
 286                                 if (injournal == 0)
 287                                         list_add_tail(&sh->lru, temp_inactive_list);
 288                                 else if (injournal == conf->raid_disks - conf->max_degraded) {
 289                                         /* full stripe */
 290                                         if (!test_and_set_bit(STRIPE_R5C_FULL_STRIPE, &sh->state))
 291                                                 atomic_inc(&conf->r5c_cached_full_stripes);
 292                                         if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
 293                                                 atomic_dec(&conf->r5c_cached_partial_stripes);
 294                                         list_add_tail(&sh->lru, &conf->r5c_full_stripe_list);
 295                                         r5c_check_cached_full_stripe(conf);
 296                                 } else
 297                                         /*
 298                                          * STRIPE_R5C_PARTIAL_STRIPE is set in
 299                                          * r5c_try_caching_write(). No need to
 300                                          * set it again.
 301                                          */
 302                                         list_add_tail(&sh->lru, &conf->r5c_partial_stripe_list);
 303                         }
 304                 }
 305         }
 306 }
 307
 308 static void __release_stripe(struct r5conf *conf, struct stripe_head *sh,
 309                              struct list_head *temp_inactive_list)
 310         __must_hold(&conf->device_lock)
 311 {
 312         if (atomic_dec_and_test(&sh->count))
 313                 do_release_stripe(conf, sh, temp_inactive_list);
 314 }
 315
 316 /*
 317  * @hash could be NR_STRIPE_HASH_LOCKS, then we have a list of inactive_list
 318  *
 319  * Be careful: Only one task can add/delete stripes from temp_inactive_list at
 320  * given time. Adding stripes only takes device lock, while deleting stripes
 321  * only takes hash lock.
 322  */
 323 static void release_inactive_stripe_list(struct r5conf *conf,
 324                                          struct list_head *temp_inactive_list,
 325                                          int hash)
 326 {
 327         int size;
 328         bool do_wakeup = false;
 329         unsigned long flags;
 330
 331         if (hash == NR_STRIPE_HASH_LOCKS) {
 332                 size = NR_STRIPE_HASH_LOCKS;
 333                 hash = NR_STRIPE_HASH_LOCKS - 1;
 334         } else
 335                 size = 1;
 336         while (size) {
 337                 struct list_head *list = &temp_inactive_list[size - 1];
 338
 339                 /*
 340                  * We don't hold any lock here yet, raid5_get_active_stripe() might
 341                  * remove stripes from the list
 342                  */
 343                 if (!list_empty_careful(list)) {
 344                         spin_lock_irqsave(conf->hash_locks + hash, flags);
 345                         if (list_empty(conf->inactive_list + hash) &&
 346                             !list_empty(list))
 347                                 atomic_dec(&conf->empty_inactive_list_nr);
 348                         list_splice_tail_init(list, conf->inactive_list + hash);
 349                         do_wakeup = true;
 350                         spin_unlock_irqrestore(conf->hash_locks + hash, flags);
 351                 }
 352                 size--;
 353                 hash--;
 354         }
 355
 356         if (do_wakeup) {
 357                 wake_up(&conf->wait_for_stripe);
 358                 if (atomic_read(&conf->active_stripes) == 0)
 359                         wake_up(&conf->wait_for_quiescent);
 360                 if (conf->retry_read_aligned)
 361                         md_wakeup_thread(conf->mddev->thread);
 362         }
 363 }
 364
 365 static int release_stripe_list(struct r5conf *conf,
 366                                struct list_head *temp_inactive_list)
 367         __must_hold(&conf->device_lock)
 368 {
 369         struct stripe_head *sh, *t;
 370         int count = 0;
 371         struct llist_node *head;
 372
 373         head = llist_del_all(&conf->released_stripes);
 374         head = llist_reverse_order(head);
 375         llist_for_each_entry_safe(sh, t, head, release_list) {
 376                 int hash;
 377
 378                 /* sh could be readded after STRIPE_ON_RELEASE_LIST is cleard */
 379                 smp_mb();
 380                 clear_bit(STRIPE_ON_RELEASE_LIST, &sh->state);
 381                 /*
 382                  * Don't worry the bit is set here, because if the bit is set
 383                  * again, the count is always > 1. This is true for
 384                  * STRIPE_ON_UNPLUG_LIST bit too.
 385                  */
 386                 hash = sh->hash_lock_index;
 387                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
 388                 count++;
 389         }
 390
 391         return count;
 392 }
 393
 394 void raid5_release_stripe(struct stripe_head *sh)
 395 {
 396         struct r5conf *conf = sh->raid_conf;
 397         unsigned long flags;
 398         struct list_head list;
 399         int hash;
 400         bool wakeup;
 401
 402         /* Avoid release_list until the last reference.
 403          */
 404         if (atomic_add_unless(&sh->count, -1, 1))
 405                 return;
 406
 407         if (unlikely(!conf->mddev->thread) ||
 408                 test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state))
 409                 goto slow_path;
 410         wakeup = llist_add(&sh->release_list, &conf->released_stripes);
 411         if (wakeup)
 412                 md_wakeup_thread(conf->mddev->thread);
 413         return;
 414 slow_path:
 415         /* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */
 416         if (atomic_dec_and_lock_irqsave(&sh->count, &conf->device_lock, flags)) {
 417                 INIT_LIST_HEAD(&list);
 418                 hash = sh->hash_lock_index;
 419                 do_release_stripe(conf, sh, &list);
 420                 spin_unlock_irqrestore(&conf->device_lock, flags);
 421                 release_inactive_stripe_list(conf, &list, hash);
 422         }
 423 }
 424
 425 static inline void remove_hash(struct stripe_head *sh)
 426 {
 427         pr_debug("remove_hash(), stripe %llu\n",
 428                 (unsigned long long)sh->sector);
 429
 430         hlist_del_init(&sh->hash);
 431 }
 432
 433 static inline void insert_hash(struct r5conf *conf, struct stripe_head *sh)
 434 {
 435         struct hlist_head *hp = stripe_hash(conf, sh->sector);
 436
 437         pr_debug("insert_hash(), stripe %llu\n",
 438                 (unsigned long long)sh->sector);
 439
 440         hlist_add_head(&sh->hash, hp);
 441 }
 442
 443 /* find an idle stripe, make sure it is unhashed, and return it. */
 444 static struct stripe_head *get_free_stripe(struct r5conf *conf, int hash)
 445 {
 446         struct stripe_head *sh = NULL;
 447         struct list_head *first;
 448
 449         if (list_empty(conf->inactive_list + hash))
 450                 goto out;
 451         first = (conf->inactive_list + hash)->next;
 452         sh = list_entry(first, struct stripe_head, lru);
 453         list_del_init(first);
 454         remove_hash(sh);
 455         atomic_inc(&conf->active_stripes);
 456         BUG_ON(hash != sh->hash_lock_index);
 457         if (list_empty(conf->inactive_list + hash))
 458                 atomic_inc(&conf->empty_inactive_list_nr);
 459 out:
 460         return sh;
 461 }
 462
 463 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
 464 static void free_stripe_pages(struct stripe_head *sh)
 465 {
 466         int i;
 467         struct page *p;
 468
 469         /* Have not allocate page pool */
 470         if (!sh->pages)
 471                 return;
 472
 473         for (i = 0; i < sh->nr_pages; i++) {
 474                 p = sh->pages[i];
 475                 if (p)
 476                         put_page(p);
 477                 sh->pages[i] = NULL;
 478         }
 479 }
 480
 481 static int alloc_stripe_pages(struct stripe_head *sh, gfp_t gfp)
 482 {
 483         int i;
 484         struct page *p;
 485
 486         for (i = 0; i < sh->nr_pages; i++) {
 487                 /* The page have allocated. */
 488                 if (sh->pages[i])
 489                         continue;
 490
 491                 p = alloc_page(gfp);
 492                 if (!p) {
 493                         free_stripe_pages(sh);
 494                         return -ENOMEM;
 495                 }
 496                 sh->pages[i] = p;
 497         }
 498         return 0;
 499 }
 500
 501 static int
 502 init_stripe_shared_pages(struct stripe_head *sh, struct r5conf *conf, int disks)
 503 {
 504         int nr_pages, cnt;
 505
 506         if (sh->pages)
 507                 return 0;
 508
 509         /* Each of the sh->dev[i] need one conf->stripe_size */
 510         cnt = PAGE_SIZE / conf->stripe_size;
 511         nr_pages = (disks + cnt - 1) / cnt;
 512
 513         sh->pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
 514         if (!sh->pages)
 515                 return -ENOMEM;
 516         sh->nr_pages = nr_pages;
 517         sh->stripes_per_page = cnt;
 518         return 0;
 519 }
 520 #endif
 521
 522 static void shrink_buffers(struct stripe_head *sh)
 523 {
 524         int i;
 525         int num = sh->raid_conf->pool_size;
 526
 527 #if PAGE_SIZE == DEFAULT_STRIPE_SIZE
 528         for (i = 0; i < num ; i++) {
 529                 struct page *p;
 530
 531                 WARN_ON(sh->dev[i].page != sh->dev[i].orig_page);
 532                 p = sh->dev[i].page;
 533                 if (!p)
 534                         continue;
 535                 sh->dev[i].page = NULL;
 536                 put_page(p);
 537         }
 538 #else
 539         for (i = 0; i < num; i++)
 540                 sh->dev[i].page = NULL;
 541         free_stripe_pages(sh); /* Free pages */
 542 #endif
 543 }
 544
 545 static int grow_buffers(struct stripe_head *sh, gfp_t gfp)
 546 {
 547         int i;
 548         int num = sh->raid_conf->pool_size;
 549
 550 #if PAGE_SIZE == DEFAULT_STRIPE_SIZE
 551         for (i = 0; i < num; i++) {
 552                 struct page *page;
 553
 554                 if (!(page = alloc_page(gfp))) {
 555                         return 1;
 556                 }
 557                 sh->dev[i].page = page;
 558                 sh->dev[i].orig_page = page;
 559                 sh->dev[i].offset = 0;
 560         }
 561 #else
 562         if (alloc_stripe_pages(sh, gfp))
 563                 return -ENOMEM;
 564
 565         for (i = 0; i < num; i++) {
 566                 sh->dev[i].page = raid5_get_dev_page(sh, i);
 567                 sh->dev[i].orig_page = sh->dev[i].page;
 568                 sh->dev[i].offset = raid5_get_page_offset(sh, i);
 569         }
 570 #endif
 571         return 0;
 572 }
 573
 574 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
 575                             struct stripe_head *sh);
 576
 577 static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
 578 {
 579         struct r5conf *conf = sh->raid_conf;
 580         int i, seq;
 581
 582         BUG_ON(atomic_read(&sh->count) != 0);
 583         BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
 584         BUG_ON(stripe_operations_active(sh));
 585         BUG_ON(sh->batch_head);
 586
 587         pr_debug("init_stripe called, stripe %llu\n",
 588                 (unsigned long long)sector);
 589 retry:
 590         seq = read_seqcount_begin(&conf->gen_lock);
 591         sh->generation = conf->generation - previous;
 592         sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
 593         sh->sector = sector;
 594         stripe_set_idx(sector, conf, previous, sh);
 595         sh->state = 0;
 596
 597         for (i = sh->disks; i--; ) {
 598                 struct r5dev *dev = &sh->dev[i];
 599
 600                 if (dev->toread || dev->read || dev->towrite || dev->written ||
 601                     test_bit(R5_LOCKED, &dev->flags)) {
 602                         pr_err("sector=%llx i=%d %p %p %p %p %d\n",
 603                                (unsigned long long)sh->sector, i, dev->toread,
 604                                dev->read, dev->towrite, dev->written,
 605                                test_bit(R5_LOCKED, &dev->flags));
 606                         WARN_ON(1);
 607                 }
 608                 dev->flags = 0;
 609                 dev->sector = raid5_compute_blocknr(sh, i, previous);
 610         }
 611         if (read_seqcount_retry(&conf->gen_lock, seq))
 612                 goto retry;
 613         sh->overwrite_disks = 0;
 614         insert_hash(conf, sh);
 615         sh->cpu = smp_processor_id();
 616         set_bit(STRIPE_BATCH_READY, &sh->state);
 617 }
 618
 619 static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
 620                                          short generation)
 621 {
 622         struct stripe_head *sh;
 623
 624         pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
 625         hlist_for_each_entry(sh, stripe_hash(conf, sector), hash)
 626                 if (sh->sector == sector && sh->generation == generation)
 627                         return sh;
 628         pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
 629         return NULL;
 630 }
 631
 632 static struct stripe_head *find_get_stripe(struct r5conf *conf,
 633                 sector_t sector, short generation, int hash)
 634 {
 635         int inc_empty_inactive_list_flag;
 636         struct stripe_head *sh;
 637
 638         sh = __find_stripe(conf, sector, generation);
 639         if (!sh)
 640                 return NULL;
 641
 642         if (atomic_inc_not_zero(&sh->count))
 643                 return sh;
 644
 645         /*
 646          * Slow path. The reference count is zero which means the stripe must
 647          * be on a list (sh->lru). Must remove the stripe from the list that
 648          * references it with the device_lock held.
 649          */
 650
 651         spin_lock(&conf->device_lock);
 652         if (!atomic_read(&sh->count)) {
 653                 if (!test_bit(STRIPE_HANDLE, &sh->state))
 654                         atomic_inc(&conf->active_stripes);
 655                 BUG_ON(list_empty(&sh->lru) &&
 656                        !test_bit(STRIPE_EXPANDING, &sh->state));
 657                 inc_empty_inactive_list_flag = 0;
 658                 if (!list_empty(conf->inactive_list + hash))
 659                         inc_empty_inactive_list_flag = 1;
 660                 list_del_init(&sh->lru);
 661                 if (list_empty(conf->inactive_list + hash) &&
 662                     inc_empty_inactive_list_flag)
 663                         atomic_inc(&conf->empty_inactive_list_nr);
 664                 if (sh->group) {
 665                         sh->group->stripes_cnt--;
 666                         sh->group = NULL;
 667                 }
 668         }
 669         atomic_inc(&sh->count);
 670         spin_unlock(&conf->device_lock);
 671
 672         return sh;
 673 }
 674
 675 /*
 676  * Need to check if array has failed when deciding whether to:
 677  *  - start an array
 678  *  - remove non-faulty devices
 679  *  - add a spare
 680  *  - allow a reshape
 681  * This determination is simple when no reshape is happening.
 682  * However if there is a reshape, we need to carefully check
 683  * both the before and after sections.
 684  * This is because some failed devices may only affect one
 685  * of the two sections, and some non-in_sync devices may
 686  * be insync in the section most affected by failed devices.
 687  *
 688  * Most calls to this function hold &conf->device_lock. Calls
 689  * in raid5_run() do not require the lock as no other threads
 690  * have been started yet.
 691  */
 692 int raid5_calc_degraded(struct r5conf *conf)
 693 {
 694         int degraded, degraded2;
 695         int i;
 696
 697         degraded = 0;
 698         for (i = 0; i < conf->previous_raid_disks; i++) {
 699                 struct md_rdev *rdev = READ_ONCE(conf->disks[i].rdev);
 700
 701                 if (rdev && test_bit(Faulty, &rdev->flags))
 702                         rdev = READ_ONCE(conf->disks[i].replacement);
 703                 if (!rdev || test_bit(Faulty, &rdev->flags))
 704                         degraded++;
 705                 else if (test_bit(In_sync, &rdev->flags))
 706                         ;
 707                 else
 708                         /* not in-sync or faulty.
 709                          * If the reshape increases the number of devices,
 710                          * this is being recovered by the reshape, so
 711                          * this 'previous' section is not in_sync.
 712                          * If the number of devices is being reduced however,
 713                          * the device can only be part of the array if
 714                          * we are reverting a reshape, so this section will
 715                          * be in-sync.
 716                          */
 717                         if (conf->raid_disks >= conf->previous_raid_disks)
 718                                 degraded++;
 719         }
 720         if (conf->raid_disks == conf->previous_raid_disks)
 721                 return degraded;
 722         degraded2 = 0;
 723         for (i = 0; i < conf->raid_disks; i++) {
 724                 struct md_rdev *rdev = READ_ONCE(conf->disks[i].rdev);
 725
 726                 if (rdev && test_bit(Faulty, &rdev->flags))
 727                         rdev = READ_ONCE(conf->disks[i].replacement);
 728                 if (!rdev || test_bit(Faulty, &rdev->flags))
 729                         degraded2++;
 730                 else if (test_bit(In_sync, &rdev->flags))
 731                         ;
 732                 else
 733                         /* not in-sync or faulty.
 734                          * If reshape increases the number of devices, this
 735                          * section has already been recovered, else it
 736                          * almost certainly hasn't.
 737                          */
 738                         if (conf->raid_disks <= conf->previous_raid_disks)
 739                                 degraded2++;
 740         }
 741         if (degraded2 > degraded)
 742                 return degraded2;
 743         return degraded;
 744 }
 745
 746 static bool has_failed(struct r5conf *conf)
 747 {
 748         int degraded = conf->mddev->degraded;
 749
 750         if (test_bit(MD_BROKEN, &conf->mddev->flags))
 751                 return true;
 752
 753         if (conf->mddev->reshape_position != MaxSector)
 754                 degraded = raid5_calc_degraded(conf);
 755
 756         return degraded > conf->max_degraded;
 757 }
 758
 759 enum stripe_result {
 760         STRIPE_SUCCESS = 0,
 761         STRIPE_RETRY,
 762         STRIPE_SCHEDULE_AND_RETRY,
 763         STRIPE_FAIL,
 764         STRIPE_WAIT_RESHAPE,
 765 };
 766
 767 struct stripe_request_ctx {
 768         /* a reference to the last stripe_head for batching */
 769         struct stripe_head *batch_last;
 770
 771         /* first sector in the request */
 772         sector_t first_sector;
 773
 774         /* last sector in the request */
 775         sector_t last_sector;
 776
 777         /*
 778          * bitmap to track stripe sectors that have been added to stripes
 779          * add one to account for unaligned requests
 780          */
 781         DECLARE_BITMAP(sectors_to_do, RAID5_MAX_REQ_STRIPES + 1);
 782
 783         /* the request had REQ_PREFLUSH, cleared after the first stripe_head */
 784         bool do_flush;
 785 };
 786
 787 /*
 788  * Block until another thread clears R5_INACTIVE_BLOCKED or
 789  * there are fewer than 3/4 the maximum number of active stripes
 790  * and there is an inactive stripe available.
 791  */
 792 static bool is_inactive_blocked(struct r5conf *conf, int hash)
 793 {
 794         if (list_empty(conf->inactive_list + hash))
 795                 return false;
 796
 797         if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
 798                 return true;
 799
 800         return (atomic_read(&conf->active_stripes) <
 801                 (conf->max_nr_stripes * 3 / 4));
 802 }
 803
 804 struct stripe_head *raid5_get_active_stripe(struct r5conf *conf,
 805                 struct stripe_request_ctx *ctx, sector_t sector,
 806                 unsigned int flags)
 807 {
 808         struct stripe_head *sh;
 809         int hash = stripe_hash_locks_hash(conf, sector);
 810         int previous = !!(flags & R5_GAS_PREVIOUS);
 811
 812         pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
 813
 814         spin_lock_irq(conf->hash_locks + hash);
 815
 816         for (;;) {
 817                 if (!(flags & R5_GAS_NOQUIESCE) && conf->quiesce) {
 818                         /*
 819                          * Must release the reference to batch_last before
 820                          * waiting, on quiesce, otherwise the batch_last will
 821                          * hold a reference to a stripe and raid5_quiesce()
 822                          * will deadlock waiting for active_stripes to go to
 823                          * zero.
 824                          */
 825                         if (ctx && ctx->batch_last) {
 826                                 raid5_release_stripe(ctx->batch_last);
 827                                 ctx->batch_last = NULL;
 828                         }
 829
 830                         wait_event_lock_irq(conf->wait_for_quiescent,
 831                                             !conf->quiesce,
 832                                             *(conf->hash_locks + hash));
 833                 }
 834
 835                 sh = find_get_stripe(conf, sector, conf->generation - previous,
 836                                      hash);
 837                 if (sh)
 838                         break;
 839
 840                 if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state)) {
 841                         sh = get_free_stripe(conf, hash);
 842                         if (sh) {
 843                                 r5c_check_stripe_cache_usage(conf);
 844                                 init_stripe(sh, sector, previous);
 845                                 atomic_inc(&sh->count);
 846                                 break;
 847                         }
 848
 849                         if (!test_bit(R5_DID_ALLOC, &conf->cache_state))
 850                                 set_bit(R5_ALLOC_MORE, &conf->cache_state);
 851                 }
 852
 853                 if (flags & R5_GAS_NOBLOCK)
 854                         break;
 855
 856                 set_bit(R5_INACTIVE_BLOCKED, &conf->cache_state);
 857                 r5l_wake_reclaim(conf->log, 0);
 858
 859                 /* release batch_last before wait to avoid risk of deadlock */
 860                 if (ctx && ctx->batch_last) {
 861                         raid5_release_stripe(ctx->batch_last);
 862                         ctx->batch_last = NULL;
 863                 }
 864
 865                 wait_event_lock_irq(conf->wait_for_stripe,
 866                                     is_inactive_blocked(conf, hash),
 867                                     *(conf->hash_locks + hash));
 868                 clear_bit(R5_INACTIVE_BLOCKED, &conf->cache_state);
 869         }
 870
 871         spin_unlock_irq(conf->hash_locks + hash);
 872         return sh;
 873 }
 874
 875 static bool is_full_stripe_write(struct stripe_head *sh)
 876 {
 877         BUG_ON(sh->overwrite_disks > (sh->disks - sh->raid_conf->max_degraded));
 878         return sh->overwrite_disks == (sh->disks - sh->raid_conf->max_degraded);
 879 }
 880
 881 static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 882                 __acquires(&sh1->stripe_lock)
 883                 __acquires(&sh2->stripe_lock)
 884 {
 885         if (sh1 > sh2) {
 886                 spin_lock_irq(&sh2->stripe_lock);
 887                 spin_lock_nested(&sh1->stripe_lock, 1);
 888         } else {
 889                 spin_lock_irq(&sh1->stripe_lock);
 890                 spin_lock_nested(&sh2->stripe_lock, 1);
 891         }
 892 }
 893
 894 static void unlock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 895                 __releases(&sh1->stripe_lock)
 896                 __releases(&sh2->stripe_lock)
 897 {
 898         spin_unlock(&sh1->stripe_lock);
 899         spin_unlock_irq(&sh2->stripe_lock);
 900 }
 901
 902 /* Only freshly new full stripe normal write stripe can be added to a batch list */
 903 static bool stripe_can_batch(struct stripe_head *sh)
 904 {
 905         struct r5conf *conf = sh->raid_conf;
 906
 907         if (raid5_has_log(conf) || raid5_has_ppl(conf))
 908                 return false;
 909         return test_bit(STRIPE_BATCH_READY, &sh->state) &&
 910                 !test_bit(STRIPE_BITMAP_PENDING, &sh->state) &&
 911                 is_full_stripe_write(sh);
 912 }
 913
 914 /* we only do back search */
 915 static void stripe_add_to_batch_list(struct r5conf *conf,
 916                 struct stripe_head *sh, struct stripe_head *last_sh)
 917 {
 918         struct stripe_head *head;
 919         sector_t head_sector, tmp_sec;
 920         int hash;
 921         int dd_idx;
 922
 923         /* Don't cross chunks, so stripe pd_idx/qd_idx is the same */
 924         tmp_sec = sh->sector;
 925         if (!sector_div(tmp_sec, conf->chunk_sectors))
 926                 return;
 927         head_sector = sh->sector - RAID5_STRIPE_SECTORS(conf);
 928
 929         if (last_sh && head_sector == last_sh->sector) {
 930                 head = last_sh;
 931                 atomic_inc(&head->count);
 932         } else {
 933                 hash = stripe_hash_locks_hash(conf, head_sector);
 934                 spin_lock_irq(conf->hash_locks + hash);
 935                 head = find_get_stripe(conf, head_sector, conf->generation,
 936                                        hash);
 937                 spin_unlock_irq(conf->hash_locks + hash);
 938                 if (!head)
 939                         return;
 940                 if (!stripe_can_batch(head))
 941                         goto out;
 942         }
 943
 944         lock_two_stripes(head, sh);
 945         /* clear_batch_ready clear the flag */
 946         if (!stripe_can_batch(head) || !stripe_can_batch(sh))
 947                 goto unlock_out;
 948
 949         if (sh->batch_head)
 950                 goto unlock_out;
 951
 952         dd_idx = 0;
 953         while (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
 954                 dd_idx++;
 955         if (head->dev[dd_idx].towrite->bi_opf != sh->dev[dd_idx].towrite->bi_opf ||
 956             bio_op(head->dev[dd_idx].towrite) != bio_op(sh->dev[dd_idx].towrite))
 957                 goto unlock_out;
 958
 959         if (head->batch_head) {
 960                 spin_lock(&head->batch_head->batch_lock);
 961                 /* This batch list is already running */
 962                 if (!stripe_can_batch(head)) {
 963                         spin_unlock(&head->batch_head->batch_lock);
 964                         goto unlock_out;
 965                 }
 966                 /*
 967                  * We must assign batch_head of this stripe within the
 968                  * batch_lock, otherwise clear_batch_ready of batch head
 969                  * stripe could clear BATCH_READY bit of this stripe and
 970                  * this stripe->batch_head doesn't get assigned, which
 971                  * could confuse clear_batch_ready for this stripe
 972                  */
 973                 sh->batch_head = head->batch_head;
 974
 975                 /*
 976                  * at this point, head's BATCH_READY could be cleared, but we
 977                  * can still add the stripe to batch list
 978                  */
 979                 list_add(&sh->batch_list, &head->batch_list);
 980                 spin_unlock(&head->batch_head->batch_lock);
 981         } else {
 982                 head->batch_head = head;
 983                 sh->batch_head = head->batch_head;
 984                 spin_lock(&head->batch_lock);
 985                 list_add_tail(&sh->batch_list, &head->batch_list);
 986                 spin_unlock(&head->batch_lock);
 987         }
 988
 989         if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 990                 if (atomic_dec_return(&conf->preread_active_stripes)
 991                     < IO_THRESHOLD)
 992                         md_wakeup_thread(conf->mddev->thread);
 993
 994         if (test_and_clear_bit(STRIPE_BIT_DELAY, &sh->state)) {
 995                 int seq = sh->bm_seq;
 996                 if (test_bit(STRIPE_BIT_DELAY, &sh->batch_head->state) &&
 997                     sh->batch_head->bm_seq > seq)
 998                         seq = sh->batch_head->bm_seq;
 999                 set_bit(STRIPE_BIT_DELAY, &sh->batch_head->state);
1000                 sh->batch_head->bm_seq = seq;
1001         }
1002
1003         atomic_inc(&sh->count);
1004 unlock_out:
1005         unlock_two_stripes(head, sh);
1006 out:
1007         raid5_release_stripe(head);
1008 }
1009
1010 /* Determine if 'data_offset' or 'new_data_offset' should be used
1011  * in this stripe_head.
1012  */
1013 static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
1014 {
1015         sector_t progress = conf->reshape_progress;
1016         /* Need a memory barrier to make sure we see the value
1017          * of conf->generation, or ->data_offset that was set before
1018          * reshape_progress was updated.
1019          */
1020         smp_rmb();
1021         if (progress == MaxSector)
1022                 return 0;
1023         if (sh->generation == conf->generation - 1)
1024                 return 0;
1025         /* We are in a reshape, and this is a new-generation stripe,
1026          * so use new_data_offset.
1027          */
1028         return 1;
1029 }
1030
1031 static void dispatch_bio_list(struct bio_list *tmp)
1032 {
1033         struct bio *bio;
1034
1035         while ((bio = bio_list_pop(tmp)))
1036                 submit_bio_noacct(bio);
1037 }
1038
1039 static int cmp_stripe(void *priv, const struct list_head *a,
1040                       const struct list_head *b)
1041 {
1042         const struct r5pending_data *da = list_entry(a,
1043                                 struct r5pending_data, sibling);
1044         const struct r5pending_data *db = list_entry(b,
1045                                 struct r5pending_data, sibling);
1046         if (da->sector > db->sector)
1047                 return 1;
1048         if (da->sector < db->sector)
1049                 return -1;
1050         return 0;
1051 }
1052
1053 static void dispatch_defer_bios(struct r5conf *conf, int target,
1054                                 struct bio_list *list)
1055 {
1056         struct r5pending_data *data;
1057         struct list_head *first, *next = NULL;
1058         int cnt = 0;
1059
1060         if (conf->pending_data_cnt == 0)
1061                 return;
1062
1063         list_sort(NULL, &conf->pending_list, cmp_stripe);
1064
1065         first = conf->pending_list.next;
1066
1067         /* temporarily move the head */
1068         if (conf->next_pending_data)
1069                 list_move_tail(&conf->pending_list,
1070                                 &conf->next_pending_data->sibling);
1071
1072         while (!list_empty(&conf->pending_list)) {
1073                 data = list_first_entry(&conf->pending_list,
1074                         struct r5pending_data, sibling);
1075                 if (&data->sibling == first)
1076                         first = data->sibling.next;
1077                 next = data->sibling.next;
1078
1079                 bio_list_merge(list, &data->bios);
1080                 list_move(&data->sibling, &conf->free_list);
1081                 cnt++;
1082                 if (cnt >= target)
1083                         break;
1084         }
1085         conf->pending_data_cnt -= cnt;
1086         BUG_ON(conf->pending_data_cnt < 0 || cnt < target);
1087
1088         if (next != &conf->pending_list)
1089                 conf->next_pending_data = list_entry(next,
1090                                 struct r5pending_data, sibling);
1091         else
1092                 conf->next_pending_data = NULL;
1093         /* list isn't empty */
1094         if (first != &conf->pending_list)
1095                 list_move_tail(&conf->pending_list, first);
1096 }
1097
1098 static void flush_deferred_bios(struct r5conf *conf)
1099 {
1100         struct bio_list tmp = BIO_EMPTY_LIST;
1101
1102         if (conf->pending_data_cnt == 0)
1103                 return;
1104
1105         spin_lock(&conf->pending_bios_lock);
1106         dispatch_defer_bios(conf, conf->pending_data_cnt, &tmp);
1107         BUG_ON(conf->pending_data_cnt != 0);
1108         spin_unlock(&conf->pending_bios_lock);
1109
1110         dispatch_bio_list(&tmp);
1111 }
1112
1113 static void defer_issue_bios(struct r5conf *conf, sector_t sector,
1114                                 struct bio_list *bios)
1115 {
1116         struct bio_list tmp = BIO_EMPTY_LIST;
1117         struct r5pending_data *ent;
1118
1119         spin_lock(&conf->pending_bios_lock);
1120         ent = list_first_entry(&conf->free_list, struct r5pending_data,
1121                                                         sibling);
1122         list_move_tail(&ent->sibling, &conf->pending_list);
1123         ent->sector = sector;
1124         bio_list_init(&ent->bios);
1125         bio_list_merge(&ent->bios, bios);
1126         conf->pending_data_cnt++;
1127         if (conf->pending_data_cnt >= PENDING_IO_MAX)
1128                 dispatch_defer_bios(conf, PENDING_IO_ONE_FLUSH, &tmp);
1129
1130         spin_unlock(&conf->pending_bios_lock);
1131
1132         dispatch_bio_list(&tmp);
1133 }
1134
1135 static void
1136 raid5_end_read_request(struct bio *bi);
1137 static void
1138 raid5_end_write_request(struct bio *bi);
1139
1140 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
1141 {
1142         struct r5conf *conf = sh->raid_conf;
1143         int i, disks = sh->disks;
1144         struct stripe_head *head_sh = sh;
1145         struct bio_list pending_bios = BIO_EMPTY_LIST;
1146         struct r5dev *dev;
1147         bool should_defer;
1148
1149         might_sleep();
1150
1151         if (log_stripe(sh, s) == 0)
1152                 return;
1153
1154         should_defer = conf->batch_bio_dispatch && conf->group_cnt;
1155
1156         for (i = disks; i--; ) {
1157                 enum req_op op;
1158                 blk_opf_t op_flags = 0;
1159                 int replace_only = 0;
1160                 struct bio *bi, *rbi;
1161                 struct md_rdev *rdev, *rrdev = NULL;
1162
1163                 sh = head_sh;
1164                 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
1165                         op = REQ_OP_WRITE;
1166                         if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
1167                                 op_flags = REQ_FUA;
1168                         if (test_bit(R5_Discard, &sh->dev[i].flags))
1169                                 op = REQ_OP_DISCARD;
1170                 } else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1171                         op = REQ_OP_READ;
1172                 else if (test_and_clear_bit(R5_WantReplace,
1173                                             &sh->dev[i].flags)) {
1174                         op = REQ_OP_WRITE;
1175                         replace_only = 1;
1176                 } else
1177                         continue;
1178                 if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
1179                         op_flags |= REQ_SYNC;
1180
1181 again:
1182                 dev = &sh->dev[i];
1183                 bi = &dev->req;
1184                 rbi = &dev->rreq; /* For writing to replacement */
1185
1186                 rdev = conf->disks[i].rdev;
1187                 rrdev = conf->disks[i].replacement;
1188                 if (op_is_write(op)) {
1189                         if (replace_only)
1190                                 rdev = NULL;
1191                         if (rdev == rrdev)
1192                                 /* We raced and saw duplicates */
1193                                 rrdev = NULL;
1194                 } else {
1195                         if (test_bit(R5_ReadRepl, &head_sh->dev[i].flags) && rrdev)
1196                                 rdev = rrdev;
1197                         rrdev = NULL;
1198                 }
1199
1200                 if (rdev && test_bit(Faulty, &rdev->flags))
1201                         rdev = NULL;
1202                 if (rdev)
1203                         atomic_inc(&rdev->nr_pending);
1204                 if (rrdev && test_bit(Faulty, &rrdev->flags))
1205                         rrdev = NULL;
1206                 if (rrdev)
1207                         atomic_inc(&rrdev->nr_pending);
1208
1209                 /* We have already checked bad blocks for reads.  Now
1210                  * need to check for writes.  We never accept write errors
1211                  * on the replacement, so we don't to check rrdev.
1212                  */
1213                 while (op_is_write(op) && rdev &&
1214                        test_bit(WriteErrorSeen, &rdev->flags)) {
1215                         int bad = rdev_has_badblock(rdev, sh->sector,
1216                                                     RAID5_STRIPE_SECTORS(conf));
1217                         if (!bad)
1218                                 break;
1219
1220                         if (bad < 0) {
1221                                 set_bit(BlockedBadBlocks, &rdev->flags);
1222                                 if (!conf->mddev->external &&
1223                                     conf->mddev->sb_flags) {
1224                                         /* It is very unlikely, but we might
1225                                          * still need to write out the
1226                                          * bad block log - better give it
1227                                          * a chance*/
1228                                         md_check_recovery(conf->mddev);
1229                                 }
1230                                 /*
1231                                  * Because md_wait_for_blocked_rdev
1232                                  * will dec nr_pending, we must
1233                                  * increment it first.
1234                                  */
1235                                 atomic_inc(&rdev->nr_pending);
1236                                 md_wait_for_blocked_rdev(rdev, conf->mddev);
1237                         } else {
1238                                 /* Acknowledged bad block - skip the write */
1239                                 rdev_dec_pending(rdev, conf->mddev);
1240                                 rdev = NULL;
1241                         }
1242                 }
1243
1244                 if (rdev) {
1245                         if (s->syncing || s->expanding || s->expanded
1246                             || s->replacing)
1247                                 md_sync_acct(rdev->bdev, RAID5_STRIPE_SECTORS(conf));
1248
1249                         set_bit(STRIPE_IO_STARTED, &sh->state);
1250
1251                         bio_init(bi, rdev->bdev, &dev->vec, 1, op | op_flags);
1252                         bi->bi_end_io = op_is_write(op)
1253                                 ? raid5_end_write_request
1254                                 : raid5_end_read_request;
1255                         bi->bi_private = sh;
1256
1257                         pr_debug("%s: for %llu schedule op %d on disc %d\n",
1258                                 __func__, (unsigned long long)sh->sector,
1259                                 bi->bi_opf, i);
1260                         atomic_inc(&sh->count);
1261                         if (sh != head_sh)
1262                                 atomic_inc(&head_sh->count);
1263                         if (use_new_offset(conf, sh))
1264                                 bi->bi_iter.bi_sector = (sh->sector
1265                                                  + rdev->new_data_offset);
1266                         else
1267                                 bi->bi_iter.bi_sector = (sh->sector
1268                                                  + rdev->data_offset);
1269                         if (test_bit(R5_ReadNoMerge, &head_sh->dev[i].flags))
1270                                 bi->bi_opf |= REQ_NOMERGE;
1271
1272                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1273                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1274
1275                         if (!op_is_write(op) &&
1276                             test_bit(R5_InJournal, &sh->dev[i].flags))
1277                                 /*
1278                                  * issuing read for a page in journal, this
1279                                  * must be preparing for prexor in rmw; read
1280                                  * the data into orig_page
1281                                  */
1282                                 sh->dev[i].vec.bv_page = sh->dev[i].orig_page;
1283                         else
1284                                 sh->dev[i].vec.bv_page = sh->dev[i].page;
1285                         bi->bi_vcnt = 1;
1286                         bi->bi_io_vec[0].bv_len = RAID5_STRIPE_SIZE(conf);
1287                         bi->bi_io_vec[0].bv_offset = sh->dev[i].offset;
1288                         bi->bi_iter.bi_size = RAID5_STRIPE_SIZE(conf);
1289                         /*
1290                          * If this is discard request, set bi_vcnt 0. We don't
1291                          * want to confuse SCSI because SCSI will replace payload
1292                          */
1293                         if (op == REQ_OP_DISCARD)
1294                                 bi->bi_vcnt = 0;
1295                         if (rrdev)
1296                                 set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
1297
1298                         mddev_trace_remap(conf->mddev, bi, sh->dev[i].sector);
1299                         if (should_defer && op_is_write(op))
1300                                 bio_list_add(&pending_bios, bi);
1301                         else
1302                                 submit_bio_noacct(bi);
1303                 }
1304                 if (rrdev) {
1305                         if (s->syncing || s->expanding || s->expanded
1306                             || s->replacing)
1307                                 md_sync_acct(rrdev->bdev, RAID5_STRIPE_SECTORS(conf));
1308
1309                         set_bit(STRIPE_IO_STARTED, &sh->state);
1310
1311                         bio_init(rbi, rrdev->bdev, &dev->rvec, 1, op | op_flags);
1312                         BUG_ON(!op_is_write(op));
1313                         rbi->bi_end_io = raid5_end_write_request;
1314                         rbi->bi_private = sh;
1315
1316                         pr_debug("%s: for %llu schedule op %d on "
1317                                  "replacement disc %d\n",
1318                                 __func__, (unsigned long long)sh->sector,
1319                                 rbi->bi_opf, i);
1320                         atomic_inc(&sh->count);
1321                         if (sh != head_sh)
1322                                 atomic_inc(&head_sh->count);
1323                         if (use_new_offset(conf, sh))
1324                                 rbi->bi_iter.bi_sector = (sh->sector
1325                                                   + rrdev->new_data_offset);
1326                         else
1327                                 rbi->bi_iter.bi_sector = (sh->sector
1328                                                   + rrdev->data_offset);
1329                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1330                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1331                         sh->dev[i].rvec.bv_page = sh->dev[i].page;
1332                         rbi->bi_vcnt = 1;
1333                         rbi->bi_io_vec[0].bv_len = RAID5_STRIPE_SIZE(conf);
1334                         rbi->bi_io_vec[0].bv_offset = sh->dev[i].offset;
1335                         rbi->bi_iter.bi_size = RAID5_STRIPE_SIZE(conf);
1336                         /*
1337                          * If this is discard request, set bi_vcnt 0. We don't
1338                          * want to confuse SCSI because SCSI will replace payload
1339                          */
1340                         if (op == REQ_OP_DISCARD)
1341                                 rbi->bi_vcnt = 0;
1342                         mddev_trace_remap(conf->mddev, rbi, sh->dev[i].sector);
1343                         if (should_defer && op_is_write(op))
1344                                 bio_list_add(&pending_bios, rbi);
1345                         else
1346                                 submit_bio_noacct(rbi);
1347                 }
1348                 if (!rdev && !rrdev) {
1349                         if (op_is_write(op))
1350                                 set_bit(STRIPE_DEGRADED, &sh->state);
1351                         pr_debug("skip op %d on disc %d for sector %llu\n",
1352                                 bi->bi_opf, i, (unsigned long long)sh->sector);
1353                         clear_bit(R5_LOCKED, &sh->dev[i].flags);
1354                         set_bit(STRIPE_HANDLE, &sh->state);
1355                 }
1356
1357                 if (!head_sh->batch_head)
1358                         continue;
1359                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1360                                       batch_list);
1361                 if (sh != head_sh)
1362                         goto again;
1363         }
1364
1365         if (should_defer && !bio_list_empty(&pending_bios))
1366                 defer_issue_bios(conf, head_sh->sector, &pending_bios);
1367 }
1368
1369 static struct dma_async_tx_descriptor *
1370 async_copy_data(int frombio, struct bio *bio, struct page **page,
1371         unsigned int poff, sector_t sector, struct dma_async_tx_descriptor *tx,
1372         struct stripe_head *sh, int no_skipcopy)
1373 {
1374         struct bio_vec bvl;
1375         struct bvec_iter iter;
1376         struct page *bio_page;
1377         int page_offset;
1378         struct async_submit_ctl submit;
1379         enum async_tx_flags flags = 0;
1380         struct r5conf *conf = sh->raid_conf;
1381
1382         if (bio->bi_iter.bi_sector >= sector)
1383                 page_offset = (signed)(bio->bi_iter.bi_sector - sector) * 512;
1384         else
1385                 page_offset = (signed)(sector - bio->bi_iter.bi_sector) * -512;
1386
1387         if (frombio)
1388                 flags |= ASYNC_TX_FENCE;
1389         init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
1390
1391         bio_for_each_segment(bvl, bio, iter) {
1392                 int len = bvl.bv_len;
1393                 int clen;
1394                 int b_offset = 0;
1395
1396                 if (page_offset < 0) {
1397                         b_offset = -page_offset;
1398                         page_offset += b_offset;
1399                         len -= b_offset;
1400                 }
1401
1402                 if (len > 0 && page_offset + len > RAID5_STRIPE_SIZE(conf))
1403                         clen = RAID5_STRIPE_SIZE(conf) - page_offset;
1404                 else
1405                         clen = len;
1406
1407                 if (clen > 0) {
1408                         b_offset += bvl.bv_offset;
1409                         bio_page = bvl.bv_page;
1410                         if (frombio) {
1411                                 if (conf->skip_copy &&
1412                                     b_offset == 0 && page_offset == 0 &&
1413                                     clen == RAID5_STRIPE_SIZE(conf) &&
1414                                     !no_skipcopy)
1415                                         *page = bio_page;
1416                                 else
1417                                         tx = async_memcpy(*page, bio_page, page_offset + poff,
1418                                                   b_offset, clen, &submit);
1419                         } else
1420                                 tx = async_memcpy(bio_page, *page, b_offset,
1421                                                   page_offset + poff, clen, &submit);
1422                 }
1423                 /* chain the operations */
1424                 submit.depend_tx = tx;
1425
1426                 if (clen < len) /* hit end of page */
1427                         break;
1428                 page_offset +=  len;
1429         }
1430
1431         return tx;
1432 }
1433
1434 static void ops_complete_biofill(void *stripe_head_ref)
1435 {
1436         struct stripe_head *sh = stripe_head_ref;
1437         int i;
1438         struct r5conf *conf = sh->raid_conf;
1439
1440         pr_debug("%s: stripe %llu\n", __func__,
1441                 (unsigned long long)sh->sector);
1442
1443         /* clear completed biofills */
1444         for (i = sh->disks; i--; ) {
1445                 struct r5dev *dev = &sh->dev[i];
1446
1447                 /* acknowledge completion of a biofill operation */
1448                 /* and check if we need to reply to a read request,
1449                  * new R5_Wantfill requests are held off until
1450                  * !STRIPE_BIOFILL_RUN
1451                  */
1452                 if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
1453                         struct bio *rbi, *rbi2;
1454
1455                         BUG_ON(!dev->read);
1456                         rbi = dev->read;
1457                         dev->read = NULL;
1458                         while (rbi && rbi->bi_iter.bi_sector <
1459                                 dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1460                                 rbi2 = r5_next_bio(conf, rbi, dev->sector);
1461                                 bio_endio(rbi);
1462                                 rbi = rbi2;
1463                         }
1464                 }
1465         }
1466         clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
1467
1468         set_bit(STRIPE_HANDLE, &sh->state);
1469         raid5_release_stripe(sh);
1470 }
1471
1472 static void ops_run_biofill(struct stripe_head *sh)
1473 {
1474         struct dma_async_tx_descriptor *tx = NULL;
1475         struct async_submit_ctl submit;
1476         int i;
1477         struct r5conf *conf = sh->raid_conf;
1478
1479         BUG_ON(sh->batch_head);
1480         pr_debug("%s: stripe %llu\n", __func__,
1481                 (unsigned long long)sh->sector);
1482
1483         for (i = sh->disks; i--; ) {
1484                 struct r5dev *dev = &sh->dev[i];
1485                 if (test_bit(R5_Wantfill, &dev->flags)) {
1486                         struct bio *rbi;
1487                         spin_lock_irq(&sh->stripe_lock);
1488                         dev->read = rbi = dev->toread;
1489                         dev->toread = NULL;
1490                         spin_unlock_irq(&sh->stripe_lock);
1491                         while (rbi && rbi->bi_iter.bi_sector <
1492                                 dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1493                                 tx = async_copy_data(0, rbi, &dev->page,
1494                                                      dev->offset,
1495                                                      dev->sector, tx, sh, 0);
1496                                 rbi = r5_next_bio(conf, rbi, dev->sector);
1497                         }
1498                 }
1499         }
1500
1501         atomic_inc(&sh->count);
1502         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
1503         async_trigger_callback(&submit);
1504 }
1505
1506 static void mark_target_uptodate(struct stripe_head *sh, int target)
1507 {
1508         struct r5dev *tgt;
1509
1510         if (target < 0)
1511                 return;
1512
1513         tgt = &sh->dev[target];
1514         set_bit(R5_UPTODATE, &tgt->flags);
1515         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1516         clear_bit(R5_Wantcompute, &tgt->flags);
1517 }
1518
1519 static void ops_complete_compute(void *stripe_head_ref)
1520 {
1521         struct stripe_head *sh = stripe_head_ref;
1522
1523         pr_debug("%s: stripe %llu\n", __func__,
1524                 (unsigned long long)sh->sector);
1525
1526         /* mark the computed target(s) as uptodate */
1527         mark_target_uptodate(sh, sh->ops.target);
1528         mark_target_uptodate(sh, sh->ops.target2);
1529
1530         clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
1531         if (sh->check_state == check_state_compute_run)
1532                 sh->check_state = check_state_compute_result;
1533         set_bit(STRIPE_HANDLE, &sh->state);
1534         raid5_release_stripe(sh);
1535 }
1536
1537 /* return a pointer to the address conversion region of the scribble buffer */
1538 static struct page **to_addr_page(struct raid5_percpu *percpu, int i)
1539 {
1540         return percpu->scribble + i * percpu->scribble_obj_size;
1541 }
1542
1543 /* return a pointer to the address conversion region of the scribble buffer */
1544 static addr_conv_t *to_addr_conv(struct stripe_head *sh,
1545                                  struct raid5_percpu *percpu, int i)
1546 {
1547         return (void *) (to_addr_page(percpu, i) + sh->disks + 2);
1548 }
1549
1550 /*
1551  * Return a pointer to record offset address.
1552  */
1553 static unsigned int *
1554 to_addr_offs(struct stripe_head *sh, struct raid5_percpu *percpu)
1555 {
1556         return (unsigned int *) (to_addr_conv(sh, percpu, 0) + sh->disks + 2);
1557 }
1558
1559 static struct dma_async_tx_descriptor *
1560 ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
1561 {
1562         int disks = sh->disks;
1563         struct page **xor_srcs = to_addr_page(percpu, 0);
1564         unsigned int *off_srcs = to_addr_offs(sh, percpu);
1565         int target = sh->ops.target;
1566         struct r5dev *tgt = &sh->dev[target];
1567         struct page *xor_dest = tgt->page;
1568         unsigned int off_dest = tgt->offset;
1569         int count = 0;
1570         struct dma_async_tx_descriptor *tx;
1571         struct async_submit_ctl submit;
1572         int i;
1573
1574         BUG_ON(sh->batch_head);
1575
1576         pr_debug("%s: stripe %llu block: %d\n",
1577                 __func__, (unsigned long long)sh->sector, target);
1578         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1579
1580         for (i = disks; i--; ) {
1581                 if (i != target) {
1582                         off_srcs[count] = sh->dev[i].offset;
1583                         xor_srcs[count++] = sh->dev[i].page;
1584                 }
1585         }
1586
1587         atomic_inc(&sh->count);
1588
1589         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
1590                           ops_complete_compute, sh, to_addr_conv(sh, percpu, 0));
1591         if (unlikely(count == 1))
1592                 tx = async_memcpy(xor_dest, xor_srcs[0], off_dest, off_srcs[0],
1593                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1594         else
1595                 tx = async_xor_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
1596                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1597
1598         return tx;
1599 }
1600
1601 /* set_syndrome_sources - populate source buffers for gen_syndrome
1602  * @srcs - (struct page *) array of size sh->disks
1603  * @offs - (unsigned int) array of offset for each page
1604  * @sh - stripe_head to parse
1605  *
1606  * Populates srcs in proper layout order for the stripe and returns the
1607  * 'count' of sources to be used in a call to async_gen_syndrome.  The P
1608  * destination buffer is recorded in srcs[count] and the Q destination
1609  * is recorded in srcs[count+1]].
1610  */
1611 static int set_syndrome_sources(struct page **srcs,
1612                                 unsigned int *offs,
1613                                 struct stripe_head *sh,
1614                                 int srctype)
1615 {
1616         int disks = sh->disks;
1617         int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
1618         int d0_idx = raid6_d0(sh);
1619         int count;
1620         int i;
1621
1622         for (i = 0; i < disks; i++)
1623                 srcs[i] = NULL;
1624
1625         count = 0;
1626         i = d0_idx;
1627         do {
1628                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1629                 struct r5dev *dev = &sh->dev[i];
1630
1631                 if (i == sh->qd_idx || i == sh->pd_idx ||
1632                     (srctype == SYNDROME_SRC_ALL) ||
1633                     (srctype == SYNDROME_SRC_WANT_DRAIN &&
1634                      (test_bit(R5_Wantdrain, &dev->flags) ||
1635                       test_bit(R5_InJournal, &dev->flags))) ||
1636                     (srctype == SYNDROME_SRC_WRITTEN &&
1637                      (dev->written ||
1638                       test_bit(R5_InJournal, &dev->flags)))) {
1639                         if (test_bit(R5_InJournal, &dev->flags))
1640                                 srcs[slot] = sh->dev[i].orig_page;
1641                         else
1642                                 srcs[slot] = sh->dev[i].page;
1643                         /*
1644                          * For R5_InJournal, PAGE_SIZE must be 4KB and will
1645                          * not shared page. In that case, dev[i].offset
1646                          * is 0.
1647                          */
1648                         offs[slot] = sh->dev[i].offset;
1649                 }
1650                 i = raid6_next_disk(i, disks);
1651         } while (i != d0_idx);
1652
1653         return syndrome_disks;
1654 }
1655
1656 static struct dma_async_tx_descriptor *
1657 ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
1658 {
1659         int disks = sh->disks;
1660         struct page **blocks = to_addr_page(percpu, 0);
1661         unsigned int *offs = to_addr_offs(sh, percpu);
1662         int target;
1663         int qd_idx = sh->qd_idx;
1664         struct dma_async_tx_descriptor *tx;
1665         struct async_submit_ctl submit;
1666         struct r5dev *tgt;
1667         struct page *dest;
1668         unsigned int dest_off;
1669         int i;
1670         int count;
1671
1672         BUG_ON(sh->batch_head);
1673         if (sh->ops.target < 0)
1674                 target = sh->ops.target2;
1675         else if (sh->ops.target2 < 0)
1676                 target = sh->ops.target;
1677         else
1678                 /* we should only have one valid target */
1679                 BUG();
1680         BUG_ON(target < 0);
1681         pr_debug("%s: stripe %llu block: %d\n",
1682                 __func__, (unsigned long long)sh->sector, target);
1683
1684         tgt = &sh->dev[target];
1685         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1686         dest = tgt->page;
1687         dest_off = tgt->offset;
1688
1689         atomic_inc(&sh->count);
1690
1691         if (target == qd_idx) {
1692                 count = set_syndrome_sources(blocks, offs, sh, SYNDROME_SRC_ALL);
1693                 blocks[count] = NULL; /* regenerating p is not necessary */
1694                 BUG_ON(blocks[count+1] != dest); /* q should already be set */
1695                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1696                                   ops_complete_compute, sh,
1697                                   to_addr_conv(sh, percpu, 0));
1698                 tx = async_gen_syndrome(blocks, offs, count+2,
1699                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1700         } else {
1701                 /* Compute any data- or p-drive using XOR */
1702                 count = 0;
1703                 for (i = disks; i-- ; ) {
1704                         if (i == target || i == qd_idx)
1705                                 continue;
1706                         offs[count] = sh->dev[i].offset;
1707                         blocks[count++] = sh->dev[i].page;
1708                 }
1709
1710                 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1711                                   NULL, ops_complete_compute, sh,
1712                                   to_addr_conv(sh, percpu, 0));
1713                 tx = async_xor_offs(dest, dest_off, blocks, offs, count,
1714                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1715         }
1716
1717         return tx;
1718 }
1719
1720 static struct dma_async_tx_descriptor *
1721 ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
1722 {
1723         int i, count, disks = sh->disks;
1724         int syndrome_disks = sh->ddf_layout ? disks : disks-2;
1725         int d0_idx = raid6_d0(sh);
1726         int faila = -1, failb = -1;
1727         int target = sh->ops.target;
1728         int target2 = sh->ops.target2;
1729         struct r5dev *tgt = &sh->dev[target];
1730         struct r5dev *tgt2 = &sh->dev[target2];
1731         struct dma_async_tx_descriptor *tx;
1732         struct page **blocks = to_addr_page(percpu, 0);
1733         unsigned int *offs = to_addr_offs(sh, percpu);
1734         struct async_submit_ctl submit;
1735
1736         BUG_ON(sh->batch_head);
1737         pr_debug("%s: stripe %llu block1: %d block2: %d\n",
1738                  __func__, (unsigned long long)sh->sector, target, target2);
1739         BUG_ON(target < 0 || target2 < 0);
1740         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1741         BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
1742
1743         /* we need to open-code set_syndrome_sources to handle the
1744          * slot number conversion for 'faila' and 'failb'
1745          */
1746         for (i = 0; i < disks ; i++) {
1747                 offs[i] = 0;
1748                 blocks[i] = NULL;
1749         }
1750         count = 0;
1751         i = d0_idx;
1752         do {
1753                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1754
1755                 offs[slot] = sh->dev[i].offset;
1756                 blocks[slot] = sh->dev[i].page;
1757
1758                 if (i == target)
1759                         faila = slot;
1760                 if (i == target2)
1761                         failb = slot;
1762                 i = raid6_next_disk(i, disks);
1763         } while (i != d0_idx);
1764
1765         BUG_ON(faila == failb);
1766         if (failb < faila)
1767                 swap(faila, failb);
1768         pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
1769                  __func__, (unsigned long long)sh->sector, faila, failb);
1770
1771         atomic_inc(&sh->count);
1772
1773         if (failb == syndrome_disks+1) {
1774                 /* Q disk is one of the missing disks */
1775                 if (faila == syndrome_disks) {
1776                         /* Missing P+Q, just recompute */
1777                         init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1778                                           ops_complete_compute, sh,
1779                                           to_addr_conv(sh, percpu, 0));
1780                         return async_gen_syndrome(blocks, offs, syndrome_disks+2,
1781                                                   RAID5_STRIPE_SIZE(sh->raid_conf),
1782                                                   &submit);
1783                 } else {
1784                         struct page *dest;
1785                         unsigned int dest_off;
1786                         int data_target;
1787                         int qd_idx = sh->qd_idx;
1788
1789                         /* Missing D+Q: recompute D from P, then recompute Q */
1790                         if (target == qd_idx)
1791                                 data_target = target2;
1792                         else
1793                                 data_target = target;
1794
1795                         count = 0;
1796                         for (i = disks; i-- ; ) {
1797                                 if (i == data_target || i == qd_idx)
1798                                         continue;
1799                                 offs[count] = sh->dev[i].offset;
1800                                 blocks[count++] = sh->dev[i].page;
1801                         }
1802                         dest = sh->dev[data_target].page;
1803                         dest_off = sh->dev[data_target].offset;
1804                         init_async_submit(&submit,
1805                                           ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1806                                           NULL, NULL, NULL,
1807                                           to_addr_conv(sh, percpu, 0));
1808                         tx = async_xor_offs(dest, dest_off, blocks, offs, count,
1809                                        RAID5_STRIPE_SIZE(sh->raid_conf),
1810                                        &submit);
1811
1812                         count = set_syndrome_sources(blocks, offs, sh, SYNDROME_SRC_ALL);
1813                         init_async_submit(&submit, ASYNC_TX_FENCE, tx,
1814                                           ops_complete_compute, sh,
1815                                           to_addr_conv(sh, percpu, 0));
1816                         return async_gen_syndrome(blocks, offs, count+2,
1817                                                   RAID5_STRIPE_SIZE(sh->raid_conf),
1818                                                   &submit);
1819                 }
1820         } else {
1821                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1822                                   ops_complete_compute, sh,
1823                                   to_addr_conv(sh, percpu, 0));
1824                 if (failb == syndrome_disks) {
1825                         /* We're missing D+P. */
1826                         return async_raid6_datap_recov(syndrome_disks+2,
1827                                                 RAID5_STRIPE_SIZE(sh->raid_conf),
1828                                                 faila,
1829                                                 blocks, offs, &submit);
1830                 } else {
1831                         /* We're missing D+D. */
1832                         return async_raid6_2data_recov(syndrome_disks+2,
1833                                                 RAID5_STRIPE_SIZE(sh->raid_conf),
1834                                                 faila, failb,
1835                                                 blocks, offs, &submit);
1836                 }
1837         }
1838 }
1839
1840 static void ops_complete_prexor(void *stripe_head_ref)
1841 {
1842         struct stripe_head *sh = stripe_head_ref;
1843
1844         pr_debug("%s: stripe %llu\n", __func__,
1845                 (unsigned long long)sh->sector);
1846
1847         if (r5c_is_writeback(sh->raid_conf->log))
1848                 /*
1849                  * raid5-cache write back uses orig_page during prexor.
1850                  * After prexor, it is time to free orig_page
1851                  */
1852                 r5c_release_extra_page(sh);
1853 }
1854
1855 static struct dma_async_tx_descriptor *
1856 ops_run_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
1857                 struct dma_async_tx_descriptor *tx)
1858 {
1859         int disks = sh->disks;
1860         struct page **xor_srcs = to_addr_page(percpu, 0);
1861         unsigned int *off_srcs = to_addr_offs(sh, percpu);
1862         int count = 0, pd_idx = sh->pd_idx, i;
1863         struct async_submit_ctl submit;
1864
1865         /* existing parity data subtracted */
1866         unsigned int off_dest = off_srcs[count] = sh->dev[pd_idx].offset;
1867         struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1868
1869         BUG_ON(sh->batch_head);
1870         pr_debug("%s: stripe %llu\n", __func__,
1871                 (unsigned long long)sh->sector);
1872
1873         for (i = disks; i--; ) {
1874                 struct r5dev *dev = &sh->dev[i];
1875                 /* Only process blocks that are known to be uptodate */
1876                 if (test_bit(R5_InJournal, &dev->flags)) {
1877                         /*
1878                          * For this case, PAGE_SIZE must be equal to 4KB and
1879                          * page offset is zero.
1880                          */
1881                         off_srcs[count] = dev->offset;
1882                         xor_srcs[count++] = dev->orig_page;
1883                 } else if (test_bit(R5_Wantdrain, &dev->flags)) {
1884                         off_srcs[count] = dev->offset;
1885                         xor_srcs[count++] = dev->page;
1886                 }
1887         }
1888
1889         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1890                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1891         tx = async_xor_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
1892                         RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1893
1894         return tx;
1895 }
1896
1897 static struct dma_async_tx_descriptor *
1898 ops_run_prexor6(struct stripe_head *sh, struct raid5_percpu *percpu,
1899                 struct dma_async_tx_descriptor *tx)
1900 {
1901         struct page **blocks = to_addr_page(percpu, 0);
1902         unsigned int *offs = to_addr_offs(sh, percpu);
1903         int count;
1904         struct async_submit_ctl submit;
1905
1906         pr_debug("%s: stripe %llu\n", __func__,
1907                 (unsigned long long)sh->sector);
1908
1909         count = set_syndrome_sources(blocks, offs, sh, SYNDROME_SRC_WANT_DRAIN);
1910
1911         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_PQ_XOR_DST, tx,
1912                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1913         tx = async_gen_syndrome(blocks, offs, count+2,
1914                         RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1915
1916         return tx;
1917 }
1918
1919 static struct dma_async_tx_descriptor *
1920 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1921 {
1922         struct r5conf *conf = sh->raid_conf;
1923         int disks = sh->disks;
1924         int i;
1925         struct stripe_head *head_sh = sh;
1926
1927         pr_debug("%s: stripe %llu\n", __func__,
1928                 (unsigned long long)sh->sector);
1929
1930         for (i = disks; i--; ) {
1931                 struct r5dev *dev;
1932                 struct bio *chosen;
1933
1934                 sh = head_sh;
1935                 if (test_and_clear_bit(R5_Wantdrain, &head_sh->dev[i].flags)) {
1936                         struct bio *wbi;
1937
1938 again:
1939                         dev = &sh->dev[i];
1940                         /*
1941                          * clear R5_InJournal, so when rewriting a page in
1942                          * journal, it is not skipped by r5l_log_stripe()
1943                          */
1944                         clear_bit(R5_InJournal, &dev->flags);
1945                         spin_lock_irq(&sh->stripe_lock);
1946                         chosen = dev->towrite;
1947                         dev->towrite = NULL;
1948                         sh->overwrite_disks = 0;
1949                         BUG_ON(dev->written);
1950                         wbi = dev->written = chosen;
1951                         spin_unlock_irq(&sh->stripe_lock);
1952                         WARN_ON(dev->page != dev->orig_page);
1953
1954                         while (wbi && wbi->bi_iter.bi_sector <
1955                                 dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1956                                 if (wbi->bi_opf & REQ_FUA)
1957                                         set_bit(R5_WantFUA, &dev->flags);
1958                                 if (wbi->bi_opf & REQ_SYNC)
1959                                         set_bit(R5_SyncIO, &dev->flags);
1960                                 if (bio_op(wbi) == REQ_OP_DISCARD)
1961                                         set_bit(R5_Discard, &dev->flags);
1962                                 else {
1963                                         tx = async_copy_data(1, wbi, &dev->page,
1964                                                              dev->offset,
1965                                                              dev->sector, tx, sh,
1966                                                              r5c_is_writeback(conf->log));
1967                                         if (dev->page != dev->orig_page &&
1968                                             !r5c_is_writeback(conf->log)) {
1969                                                 set_bit(R5_SkipCopy, &dev->flags);
1970                                                 clear_bit(R5_UPTODATE, &dev->flags);
1971                                                 clear_bit(R5_OVERWRITE, &dev->flags);
1972                                         }
1973                                 }
1974                                 wbi = r5_next_bio(conf, wbi, dev->sector);
1975                         }
1976
1977                         if (head_sh->batch_head) {
1978                                 sh = list_first_entry(&sh->batch_list,
1979                                                       struct stripe_head,
1980                                                       batch_list);
1981                                 if (sh == head_sh)
1982                                         continue;
1983                                 goto again;
1984                         }
1985                 }
1986         }
1987
1988         return tx;
1989 }
1990
1991 static void ops_complete_reconstruct(void *stripe_head_ref)
1992 {
1993         struct stripe_head *sh = stripe_head_ref;
1994         int disks = sh->disks;
1995         int pd_idx = sh->pd_idx;
1996         int qd_idx = sh->qd_idx;
1997         int i;
1998         bool fua = false, sync = false, discard = false;
1999
2000         pr_debug("%s: stripe %llu\n", __func__,
2001                 (unsigned long long)sh->sector);
2002
2003         for (i = disks; i--; ) {
2004                 fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
2005                 sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
2006                 discard |= test_bit(R5_Discard, &sh->dev[i].flags);
2007         }
2008
2009         for (i = disks; i--; ) {
2010                 struct r5dev *dev = &sh->dev[i];
2011
2012                 if (dev->written || i == pd_idx || i == qd_idx) {
2013                         if (!discard && !test_bit(R5_SkipCopy, &dev->flags)) {
2014                                 set_bit(R5_UPTODATE, &dev->flags);
2015                                 if (test_bit(STRIPE_EXPAND_READY, &sh->state))
2016                                         set_bit(R5_Expanded, &dev->flags);
2017                         }
2018                         if (fua)
2019                                 set_bit(R5_WantFUA, &dev->flags);
2020                         if (sync)
2021                                 set_bit(R5_SyncIO, &dev->flags);
2022                 }
2023         }
2024
2025         if (sh->reconstruct_state == reconstruct_state_drain_run)
2026                 sh->reconstruct_state = reconstruct_state_drain_result;
2027         else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
2028                 sh->reconstruct_state = reconstruct_state_prexor_drain_result;
2029         else {
2030                 BUG_ON(sh->reconstruct_state != reconstruct_state_run);
2031                 sh->reconstruct_state = reconstruct_state_result;
2032         }
2033
2034         set_bit(STRIPE_HANDLE, &sh->state);
2035         raid5_release_stripe(sh);
2036 }
2037
2038 static void
2039 ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
2040                      struct dma_async_tx_descriptor *tx)
2041 {
2042         int disks = sh->disks;
2043         struct page **xor_srcs;
2044         unsigned int *off_srcs;
2045         struct async_submit_ctl submit;
2046         int count, pd_idx = sh->pd_idx, i;
2047         struct page *xor_dest;
2048         unsigned int off_dest;
2049         int prexor = 0;
2050         unsigned long flags;
2051         int j = 0;
2052         struct stripe_head *head_sh = sh;
2053         int last_stripe;
2054
2055         pr_debug("%s: stripe %llu\n", __func__,
2056                 (unsigned long long)sh->sector);
2057
2058         for (i = 0; i < sh->disks; i++) {
2059                 if (pd_idx == i)
2060                         continue;
2061                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
2062                         break;
2063         }
2064         if (i >= sh->disks) {
2065                 atomic_inc(&sh->count);
2066                 set_bit(R5_Discard, &sh->dev[pd_idx].flags);
2067                 ops_complete_reconstruct(sh);
2068                 return;
2069         }
2070 again:
2071         count = 0;
2072         xor_srcs = to_addr_page(percpu, j);
2073         off_srcs = to_addr_offs(sh, percpu);
2074         /* check if prexor is active which means only process blocks
2075          * that are part of a read-modify-write (written)
2076          */
2077         if (head_sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
2078                 prexor = 1;
2079                 off_dest = off_srcs[count] = sh->dev[pd_idx].offset;
2080                 xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
2081                 for (i = disks; i--; ) {
2082                         struct r5dev *dev = &sh->dev[i];
2083                         if (head_sh->dev[i].written ||
2084                             test_bit(R5_InJournal, &head_sh->dev[i].flags)) {
2085                                 off_srcs[count] = dev->offset;
2086                                 xor_srcs[count++] = dev->page;
2087                         }
2088                 }
2089         } else {
2090                 xor_dest = sh->dev[pd_idx].page;
2091                 off_dest = sh->dev[pd_idx].offset;
2092                 for (i = disks; i--; ) {
2093                         struct r5dev *dev = &sh->dev[i];
2094                         if (i != pd_idx) {
2095                                 off_srcs[count] = dev->offset;
2096                                 xor_srcs[count++] = dev->page;
2097                         }
2098                 }
2099         }
2100
2101         /* 1/ if we prexor'd then the dest is reused as a source
2102          * 2/ if we did not prexor then we are redoing the parity
2103          * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
2104          * for the synchronous xor case
2105          */
2106         last_stripe = !head_sh->batch_head ||
2107                 list_first_entry(&sh->batch_list,
2108                                  struct stripe_head, batch_list) == head_sh;
2109         if (last_stripe) {
2110                 flags = ASYNC_TX_ACK |
2111                         (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
2112
2113                 atomic_inc(&head_sh->count);
2114                 init_async_submit(&submit, flags, tx, ops_complete_reconstruct, head_sh,
2115                                   to_addr_conv(sh, percpu, j));
2116         } else {
2117                 flags = prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST;
2118                 init_async_submit(&submit, flags, tx, NULL, NULL,
2119                                   to_addr_conv(sh, percpu, j));
2120         }
2121
2122         if (unlikely(count == 1))
2123                 tx = async_memcpy(xor_dest, xor_srcs[0], off_dest, off_srcs[0],
2124                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
2125         else
2126                 tx = async_xor_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
2127                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
2128         if (!last_stripe) {
2129                 j++;
2130                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
2131                                       batch_list);
2132                 goto again;
2133         }
2134 }
2135
2136 static void
2137 ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
2138                      struct dma_async_tx_descriptor *tx)
2139 {
2140         struct async_submit_ctl submit;
2141         struct page **blocks;
2142         unsigned int *offs;
2143         int count, i, j = 0;
2144         struct stripe_head *head_sh = sh;
2145         int last_stripe;
2146         int synflags;
2147         unsigned long txflags;
2148
2149         pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
2150
2151         for (i = 0; i < sh->disks; i++) {
2152                 if (sh->pd_idx == i || sh->qd_idx == i)
2153                         continue;
2154                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
2155                         break;
2156         }
2157         if (i >= sh->disks) {
2158                 atomic_inc(&sh->count);
2159                 set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
2160                 set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
2161                 ops_complete_reconstruct(sh);
2162                 return;
2163         }
2164
2165 again:
2166         blocks = to_addr_page(percpu, j);
2167         offs = to_addr_offs(sh, percpu);
2168
2169         if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
2170                 synflags = SYNDROME_SRC_WRITTEN;
2171                 txflags = ASYNC_TX_ACK | ASYNC_TX_PQ_XOR_DST;
2172         } else {
2173                 synflags = SYNDROME_SRC_ALL;
2174                 txflags = ASYNC_TX_ACK;
2175         }
2176
2177         count = set_syndrome_sources(blocks, offs, sh, synflags);
2178         last_stripe = !head_sh->batch_head ||
2179                 list_first_entry(&sh->batch_list,
2180                                  struct stripe_head, batch_list) == head_sh;
2181
2182         if (last_stripe) {
2183                 atomic_inc(&head_sh->count);
2184                 init_async_submit(&submit, txflags, tx, ops_complete_reconstruct,
2185                                   head_sh, to_addr_conv(sh, percpu, j));
2186         } else
2187                 init_async_submit(&submit, 0, tx, NULL, NULL,
2188                                   to_addr_conv(sh, percpu, j));
2189         tx = async_gen_syndrome(blocks, offs, count+2,
2190                         RAID5_STRIPE_SIZE(sh->raid_conf),  &submit);
2191         if (!last_stripe) {
2192                 j++;
2193                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
2194                                       batch_list);
2195                 goto again;
2196         }
2197 }
2198
2199 static void ops_complete_check(void *stripe_head_ref)
2200 {
2201         struct stripe_head *sh = stripe_head_ref;
2202
2203         pr_debug("%s: stripe %llu\n", __func__,
2204                 (unsigned long long)sh->sector);
2205
2206         sh->check_state = check_state_check_result;
2207         set_bit(STRIPE_HANDLE, &sh->state);
2208         raid5_release_stripe(sh);
2209 }
2210
2211 static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
2212 {
2213         int disks = sh->disks;
2214         int pd_idx = sh->pd_idx;
2215         int qd_idx = sh->qd_idx;
2216         struct page *xor_dest;
2217         unsigned int off_dest;
2218         struct page **xor_srcs = to_addr_page(percpu, 0);
2219         unsigned int *off_srcs = to_addr_offs(sh, percpu);
2220         struct dma_async_tx_descriptor *tx;
2221         struct async_submit_ctl submit;
2222         int count;
2223         int i;
2224
2225         pr_debug("%s: stripe %llu\n", __func__,
2226                 (unsigned long long)sh->sector);
2227
2228         BUG_ON(sh->batch_head);
2229         count = 0;
2230         xor_dest = sh->dev[pd_idx].page;
2231         off_dest = sh->dev[pd_idx].offset;
2232         off_srcs[count] = off_dest;
2233         xor_srcs[count++] = xor_dest;
2234         for (i = disks; i--; ) {
2235                 if (i == pd_idx || i == qd_idx)
2236                         continue;
2237                 off_srcs[count] = sh->dev[i].offset;
2238                 xor_srcs[count++] = sh->dev[i].page;
2239         }
2240
2241         init_async_submit(&submit, 0, NULL, NULL, NULL,
2242                           to_addr_conv(sh, percpu, 0));
2243         tx = async_xor_val_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
2244                            RAID5_STRIPE_SIZE(sh->raid_conf),
2245                            &sh->ops.zero_sum_result, &submit);
2246
2247         atomic_inc(&sh->count);
2248         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
2249         tx = async_trigger_callback(&submit);
2250 }
2251
2252 static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
2253 {
2254         struct page **srcs = to_addr_page(percpu, 0);
2255         unsigned int *offs = to_addr_offs(sh, percpu);
2256         struct async_submit_ctl submit;
2257         int count;
2258
2259         pr_debug("%s: stripe %llu checkp: %d\n", __func__,
2260                 (unsigned long long)sh->sector, checkp);
2261
2262         BUG_ON(sh->batch_head);
2263         count = set_syndrome_sources(srcs, offs, sh, SYNDROME_SRC_ALL);
2264         if (!checkp)
2265                 srcs[count] = NULL;
2266
2267         atomic_inc(&sh->count);
2268         init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
2269                           sh, to_addr_conv(sh, percpu, 0));
2270         async_syndrome_val(srcs, offs, count+2,
2271                            RAID5_STRIPE_SIZE(sh->raid_conf),
2272                            &sh->ops.zero_sum_result, percpu->spare_page, 0, &submit);
2273 }
2274
2275 static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
2276 {
2277         int overlap_clear = 0, i, disks = sh->disks;
2278         struct dma_async_tx_descriptor *tx = NULL;
2279         struct r5conf *conf = sh->raid_conf;
2280         int level = conf->level;
2281         struct raid5_percpu *percpu;
2282
2283         local_lock(&conf->percpu->lock);
2284         percpu = this_cpu_ptr(conf->percpu);
2285         if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
2286                 ops_run_biofill(sh);
2287                 overlap_clear++;
2288         }
2289
2290         if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
2291                 if (level < 6)
2292                         tx = ops_run_compute5(sh, percpu);
2293                 else {
2294                         if (sh->ops.target2 < 0 || sh->ops.target < 0)
2295                                 tx = ops_run_compute6_1(sh, percpu);
2296                         else
2297                                 tx = ops_run_compute6_2(sh, percpu);
2298                 }
2299                 /* terminate the chain if reconstruct is not set to be run */
2300                 if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
2301                         async_tx_ack(tx);
2302         }
2303
2304         if (test_bit(STRIPE_OP_PREXOR, &ops_request)) {
2305                 if (level < 6)
2306                         tx = ops_run_prexor5(sh, percpu, tx);
2307                 else
2308                         tx = ops_run_prexor6(sh, percpu, tx);
2309         }
2310
2311         if (test_bit(STRIPE_OP_PARTIAL_PARITY, &ops_request))
2312                 tx = ops_run_partial_parity(sh, percpu, tx);
2313
2314         if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
2315                 tx = ops_run_biodrain(sh, tx);
2316                 overlap_clear++;
2317         }
2318
2319         if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
2320                 if (level < 6)
2321                         ops_run_reconstruct5(sh, percpu, tx);
2322                 else
2323                         ops_run_reconstruct6(sh, percpu, tx);
2324         }
2325
2326         if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
2327                 if (sh->check_state == check_state_run)
2328                         ops_run_check_p(sh, percpu);
2329                 else if (sh->check_state == check_state_run_q)
2330                         ops_run_check_pq(sh, percpu, 0);
2331                 else if (sh->check_state == check_state_run_pq)
2332                         ops_run_check_pq(sh, percpu, 1);
2333                 else
2334                         BUG();
2335         }
2336
2337         if (overlap_clear && !sh->batch_head) {
2338                 for (i = disks; i--; ) {
2339                         struct r5dev *dev = &sh->dev[i];
2340                         if (test_and_clear_bit(R5_Overlap, &dev->flags))
2341                                 wake_up(&sh->raid_conf->wait_for_overlap);
2342                 }
2343         }
2344         local_unlock(&conf->percpu->lock);
2345 }
2346
2347 static void free_stripe(struct kmem_cache *sc, struct stripe_head *sh)
2348 {
2349 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2350         kfree(sh->pages);
2351 #endif
2352         if (sh->ppl_page)
2353                 __free_page(sh->ppl_page);
2354         kmem_cache_free(sc, sh);
2355 }
2356
2357 static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp,
2358         int disks, struct r5conf *conf)
2359 {
2360         struct stripe_head *sh;
2361
2362         sh = kmem_cache_zalloc(sc, gfp);
2363         if (sh) {
2364                 spin_lock_init(&sh->stripe_lock);
2365                 spin_lock_init(&sh->batch_lock);
2366                 INIT_LIST_HEAD(&sh->batch_list);
2367                 INIT_LIST_HEAD(&sh->lru);
2368                 INIT_LIST_HEAD(&sh->r5c);
2369                 INIT_LIST_HEAD(&sh->log_list);
2370                 atomic_set(&sh->count, 1);
2371                 sh->raid_conf = conf;
2372                 sh->log_start = MaxSector;
2373
2374                 if (raid5_has_ppl(conf)) {
2375                         sh->ppl_page = alloc_page(gfp);
2376                         if (!sh->ppl_page) {
2377                                 free_stripe(sc, sh);
2378                                 return NULL;
2379                         }
2380                 }
2381 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2382                 if (init_stripe_shared_pages(sh, conf, disks)) {
2383                         free_stripe(sc, sh);
2384                         return NULL;
2385                 }
2386 #endif
2387         }
2388         return sh;
2389 }
2390 static int grow_one_stripe(struct r5conf *conf, gfp_t gfp)
2391 {
2392         struct stripe_head *sh;
2393
2394         sh = alloc_stripe(conf->slab_cache, gfp, conf->pool_size, conf);
2395         if (!sh)
2396                 return 0;
2397
2398         if (grow_buffers(sh, gfp)) {
2399                 shrink_buffers(sh);
2400                 free_stripe(conf->slab_cache, sh);
2401                 return 0;
2402         }
2403         sh->hash_lock_index =
2404                 conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS;
2405         /* we just created an active stripe so... */
2406         atomic_inc(&conf->active_stripes);
2407
2408         raid5_release_stripe(sh);
2409         WRITE_ONCE(conf->max_nr_stripes, conf->max_nr_stripes + 1);
2410         return 1;
2411 }
2412
2413 static int grow_stripes(struct r5conf *conf, int num)
2414 {
2415         struct kmem_cache *sc;
2416         size_t namelen = sizeof(conf->cache_name[0]);
2417         int devs = max(conf->raid_disks, conf->previous_raid_disks);
2418
2419         if (mddev_is_dm(conf->mddev))
2420                 snprintf(conf->cache_name[0], namelen,
2421                         "raid%d-%p", conf->level, conf->mddev);
2422         else
2423                 snprintf(conf->cache_name[0], namelen,
2424                         "raid%d-%s", conf->level, mdname(conf->mddev));
2425         snprintf(conf->cache_name[1], namelen, "%.27s-alt", conf->cache_name[0]);
2426
2427         conf->active_name = 0;
2428         sc = kmem_cache_create(conf->cache_name[conf->active_name],
2429                                struct_size_t(struct stripe_head, dev, devs),
2430                                0, 0, NULL);
2431         if (!sc)
2432                 return 1;
2433         conf->slab_cache = sc;
2434         conf->pool_size = devs;
2435         while (num--)
2436                 if (!grow_one_stripe(conf, GFP_KERNEL))
2437                         return 1;
2438
2439         return 0;
2440 }
2441
2442 /**
2443  * scribble_alloc - allocate percpu scribble buffer for required size
2444  *                  of the scribble region
2445  * @percpu: from for_each_present_cpu() of the caller
2446  * @num: total number of disks in the array
2447  * @cnt: scribble objs count for required size of the scribble region
2448  *
2449  * The scribble buffer size must be enough to contain:
2450  * 1/ a struct page pointer for each device in the array +2
2451  * 2/ room to convert each entry in (1) to its corresponding dma
2452  *    (dma_map_page()) or page (page_address()) address.
2453  *
2454  * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
2455  * calculate over all devices (not just the data blocks), using zeros in place
2456  * of the P and Q blocks.
2457  */
2458 static int scribble_alloc(struct raid5_percpu *percpu,
2459                           int num, int cnt)
2460 {
2461         size_t obj_size =
2462                 sizeof(struct page *) * (num + 2) +
2463                 sizeof(addr_conv_t) * (num + 2) +
2464                 sizeof(unsigned int) * (num + 2);
2465         void *scribble;
2466
2467         /*
2468          * If here is in raid array suspend context, it is in memalloc noio
2469          * context as well, there is no potential recursive memory reclaim
2470          * I/Os with the GFP_KERNEL flag.
2471          */
2472         scribble = kvmalloc_array(cnt, obj_size, GFP_KERNEL);
2473         if (!scribble)
2474                 return -ENOMEM;
2475
2476         kvfree(percpu->scribble);
2477
2478         percpu->scribble = scribble;
2479         percpu->scribble_obj_size = obj_size;
2480         return 0;
2481 }
2482
2483 static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
2484 {
2485         unsigned long cpu;
2486         int err = 0;
2487
2488         /* Never shrink. */
2489         if (conf->scribble_disks >= new_disks &&
2490             conf->scribble_sectors >= new_sectors)
2491                 return 0;
2492
2493         raid5_quiesce(conf->mddev, true);
2494         cpus_read_lock();
2495
2496         for_each_present_cpu(cpu) {
2497                 struct raid5_percpu *percpu;
2498
2499                 percpu = per_cpu_ptr(conf->percpu, cpu);
2500                 err = scribble_alloc(percpu, new_disks,
2501                                      new_sectors / RAID5_STRIPE_SECTORS(conf));
2502                 if (err)
2503                         break;
2504         }
2505
2506         cpus_read_unlock();
2507         raid5_quiesce(conf->mddev, false);
2508
2509         if (!err) {
2510                 conf->scribble_disks = new_disks;
2511                 conf->scribble_sectors = new_sectors;
2512         }
2513         return err;
2514 }
2515
2516 static int resize_stripes(struct r5conf *conf, int newsize)
2517 {
2518         /* Make all the stripes able to hold 'newsize' devices.
2519          * New slots in each stripe get 'page' set to a new page.
2520          *
2521          * This happens in stages:
2522          * 1/ create a new kmem_cache and allocate the required number of
2523          *    stripe_heads.
2524          * 2/ gather all the old stripe_heads and transfer the pages across
2525          *    to the new stripe_heads.  This will have the side effect of
2526          *    freezing the array as once all stripe_heads have been collected,
2527          *    no IO will be possible.  Old stripe heads are freed once their
2528          *    pages have been transferred over, and the old kmem_cache is
2529          *    freed when all stripes are done.
2530          * 3/ reallocate conf->disks to be suitable bigger.  If this fails,
2531          *    we simple return a failure status - no need to clean anything up.
2532          * 4/ allocate new pages for the new slots in the new stripe_heads.
2533          *    If this fails, we don't bother trying the shrink the
2534          *    stripe_heads down again, we just leave them as they are.
2535          *    As each stripe_head is processed the new one is released into
2536          *    active service.
2537          *
2538          * Once step2 is started, we cannot afford to wait for a write,
2539          * so we use GFP_NOIO allocations.
2540          */
2541         struct stripe_head *osh, *nsh;
2542         LIST_HEAD(newstripes);
2543         struct disk_info *ndisks;
2544         int err = 0;
2545         struct kmem_cache *sc;
2546         int i;
2547         int hash, cnt;
2548
2549         md_allow_write(conf->mddev);
2550
2551         /* Step 1 */
2552         sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
2553                                struct_size_t(struct stripe_head, dev, newsize),
2554                                0, 0, NULL);
2555         if (!sc)
2556                 return -ENOMEM;
2557
2558         /* Need to ensure auto-resizing doesn't interfere */
2559         mutex_lock(&conf->cache_size_mutex);
2560
2561         for (i = conf->max_nr_stripes; i; i--) {
2562                 nsh = alloc_stripe(sc, GFP_KERNEL, newsize, conf);
2563                 if (!nsh)
2564                         break;
2565
2566                 list_add(&nsh->lru, &newstripes);
2567         }
2568         if (i) {
2569                 /* didn't get enough, give up */
2570                 while (!list_empty(&newstripes)) {
2571                         nsh = list_entry(newstripes.next, struct stripe_head, lru);
2572                         list_del(&nsh->lru);
2573                         free_stripe(sc, nsh);
2574                 }
2575                 kmem_cache_destroy(sc);
2576                 mutex_unlock(&conf->cache_size_mutex);
2577                 return -ENOMEM;
2578         }
2579         /* Step 2 - Must use GFP_NOIO now.
2580          * OK, we have enough stripes, start collecting inactive
2581          * stripes and copying them over
2582          */
2583         hash = 0;
2584         cnt = 0;
2585         list_for_each_entry(nsh, &newstripes, lru) {
2586                 lock_device_hash_lock(conf, hash);
2587                 wait_event_cmd(conf->wait_for_stripe,
2588                                     !list_empty(conf->inactive_list + hash),
2589                                     unlock_device_hash_lock(conf, hash),
2590                                     lock_device_hash_lock(conf, hash));
2591                 osh = get_free_stripe(conf, hash);
2592                 unlock_device_hash_lock(conf, hash);
2593
2594 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2595         for (i = 0; i < osh->nr_pages; i++) {
2596                 nsh->pages[i] = osh->pages[i];
2597                 osh->pages[i] = NULL;
2598         }
2599 #endif
2600                 for(i=0; i<conf->pool_size; i++) {
2601                         nsh->dev[i].page = osh->dev[i].page;
2602                         nsh->dev[i].orig_page = osh->dev[i].page;
2603                         nsh->dev[i].offset = osh->dev[i].offset;
2604                 }
2605                 nsh->hash_lock_index = hash;
2606                 free_stripe(conf->slab_cache, osh);
2607                 cnt++;
2608                 if (cnt >= conf->max_nr_stripes / NR_STRIPE_HASH_LOCKS +
2609                     !!((conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS) > hash)) {
2610                         hash++;
2611                         cnt = 0;
2612                 }
2613         }
2614         kmem_cache_destroy(conf->slab_cache);
2615
2616         /* Step 3.
2617          * At this point, we are holding all the stripes so the array
2618          * is completely stalled, so now is a good time to resize
2619          * conf->disks and the scribble region
2620          */
2621         ndisks = kcalloc(newsize, sizeof(struct disk_info), GFP_NOIO);
2622         if (ndisks) {
2623                 for (i = 0; i < conf->pool_size; i++)
2624                         ndisks[i] = conf->disks[i];
2625
2626                 for (i = conf->pool_size; i < newsize; i++) {
2627                         ndisks[i].extra_page = alloc_page(GFP_NOIO);
2628                         if (!ndisks[i].extra_page)
2629                                 err = -ENOMEM;
2630                 }
2631
2632                 if (err) {
2633                         for (i = conf->pool_size; i < newsize; i++)
2634                                 if (ndisks[i].extra_page)
2635                                         put_page(ndisks[i].extra_page);
2636                         kfree(ndisks);
2637                 } else {
2638                         kfree(conf->disks);
2639                         conf->disks = ndisks;
2640                 }
2641         } else
2642                 err = -ENOMEM;
2643
2644         conf->slab_cache = sc;
2645         conf->active_name = 1-conf->active_name;
2646
2647         /* Step 4, return new stripes to service */
2648         while(!list_empty(&newstripes)) {
2649                 nsh = list_entry(newstripes.next, struct stripe_head, lru);
2650                 list_del_init(&nsh->lru);
2651
2652 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2653                 for (i = 0; i < nsh->nr_pages; i++) {
2654                         if (nsh->pages[i])
2655                                 continue;
2656                         nsh->pages[i] = alloc_page(GFP_NOIO);
2657                         if (!nsh->pages[i])
2658                                 err = -ENOMEM;
2659                 }
2660
2661                 for (i = conf->raid_disks; i < newsize; i++) {
2662                         if (nsh->dev[i].page)
2663                                 continue;
2664                         nsh->dev[i].page = raid5_get_dev_page(nsh, i);
2665                         nsh->dev[i].orig_page = nsh->dev[i].page;
2666                         nsh->dev[i].offset = raid5_get_page_offset(nsh, i);
2667                 }
2668 #else
2669                 for (i=conf->raid_disks; i < newsize; i++)
2670                         if (nsh->dev[i].page == NULL) {
2671                                 struct page *p = alloc_page(GFP_NOIO);
2672                                 nsh->dev[i].page = p;
2673                                 nsh->dev[i].orig_page = p;
2674                                 nsh->dev[i].offset = 0;
2675                                 if (!p)
2676                                         err = -ENOMEM;
2677                         }
2678 #endif
2679                 raid5_release_stripe(nsh);
2680         }
2681         /* critical section pass, GFP_NOIO no longer needed */
2682
2683         if (!err)
2684                 conf->pool_size = newsize;
2685         mutex_unlock(&conf->cache_size_mutex);
2686
2687         return err;
2688 }
2689
2690 static int drop_one_stripe(struct r5conf *conf)
2691 {
2692         struct stripe_head *sh;
2693         int hash = (conf->max_nr_stripes - 1) & STRIPE_HASH_LOCKS_MASK;
2694
2695         spin_lock_irq(conf->hash_locks + hash);
2696         sh = get_free_stripe(conf, hash);
2697         spin_unlock_irq(conf->hash_locks + hash);
2698         if (!sh)
2699                 return 0;
2700         BUG_ON(atomic_read(&sh->count));
2701         shrink_buffers(sh);
2702         free_stripe(conf->slab_cache, sh);
2703         atomic_dec(&conf->active_stripes);
2704         WRITE_ONCE(conf->max_nr_stripes, conf->max_nr_stripes - 1);
2705         return 1;
2706 }
2707
2708 static void shrink_stripes(struct r5conf *conf)
2709 {
2710         while (conf->max_nr_stripes &&
2711                drop_one_stripe(conf))
2712                 ;
2713
2714         kmem_cache_destroy(conf->slab_cache);
2715         conf->slab_cache = NULL;
2716 }
2717
2718 static void raid5_end_read_request(struct bio * bi)
2719 {
2720         struct stripe_head *sh = bi->bi_private;
2721         struct r5conf *conf = sh->raid_conf;
2722         int disks = sh->disks, i;
2723         struct md_rdev *rdev = NULL;
2724         sector_t s;
2725
2726         for (i=0 ; i<disks; i++)
2727                 if (bi == &sh->dev[i].req)
2728                         break;
2729
2730         pr_debug("end_read_request %llu/%d, count: %d, error %d.\n",
2731                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2732                 bi->bi_status);
2733         if (i == disks) {
2734                 BUG();
2735                 return;
2736         }
2737         if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2738                 /* If replacement finished while this request was outstanding,
2739                  * 'replacement' might be NULL already.
2740                  * In that case it moved down to 'rdev'.
2741                  * rdev is not removed until all requests are finished.
2742                  */
2743                 rdev = conf->disks[i].replacement;
2744         if (!rdev)
2745                 rdev = conf->disks[i].rdev;
2746
2747         if (use_new_offset(conf, sh))
2748                 s = sh->sector + rdev->new_data_offset;
2749         else
2750                 s = sh->sector + rdev->data_offset;
2751         if (!bi->bi_status) {
2752                 set_bit(R5_UPTODATE, &sh->dev[i].flags);
2753                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2754                         /* Note that this cannot happen on a
2755                          * replacement device.  We just fail those on
2756                          * any error
2757                          */
2758                         pr_info_ratelimited(
2759                                 "md/raid:%s: read error corrected (%lu sectors at %llu on %pg)\n",
2760                                 mdname(conf->mddev), RAID5_STRIPE_SECTORS(conf),
2761                                 (unsigned long long)s,
2762                                 rdev->bdev);
2763                         atomic_add(RAID5_STRIPE_SECTORS(conf), &rdev->corrected_errors);
2764                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2765                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2766                 } else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2767                         clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2768
2769                 if (test_bit(R5_InJournal, &sh->dev[i].flags))
2770                         /*
2771                          * end read for a page in journal, this
2772                          * must be preparing for prexor in rmw
2773                          */
2774                         set_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags);
2775
2776                 if (atomic_read(&rdev->read_errors))
2777                         atomic_set(&rdev->read_errors, 0);
2778         } else {
2779                 int retry = 0;
2780                 int set_bad = 0;
2781
2782                 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
2783                 if (!(bi->bi_status == BLK_STS_PROTECTION))
2784                         atomic_inc(&rdev->read_errors);
2785                 if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2786                         pr_warn_ratelimited(
2787                                 "md/raid:%s: read error on replacement device (sector %llu on %pg).\n",
2788                                 mdname(conf->mddev),
2789                                 (unsigned long long)s,
2790                                 rdev->bdev);
2791                 else if (conf->mddev->degraded >= conf->max_degraded) {
2792                         set_bad = 1;
2793                         pr_warn_ratelimited(
2794                                 "md/raid:%s: read error not correctable (sector %llu on %pg).\n",
2795                                 mdname(conf->mddev),
2796                                 (unsigned long long)s,
2797                                 rdev->bdev);
2798                 } else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
2799                         /* Oh, no!!! */
2800                         set_bad = 1;
2801                         pr_warn_ratelimited(
2802                                 "md/raid:%s: read error NOT corrected!! (sector %llu on %pg).\n",
2803                                 mdname(conf->mddev),
2804                                 (unsigned long long)s,
2805                                 rdev->bdev);
2806                 } else if (atomic_read(&rdev->read_errors)
2807                          > conf->max_nr_stripes) {
2808                         if (!test_bit(Faulty, &rdev->flags)) {
2809                                 pr_warn("md/raid:%s: %d read_errors > %d stripes\n",
2810                                     mdname(conf->mddev),
2811                                     atomic_read(&rdev->read_errors),
2812                                     conf->max_nr_stripes);
2813                                 pr_warn("md/raid:%s: Too many read errors, failing device %pg.\n",
2814                                     mdname(conf->mddev), rdev->bdev);
2815                         }
2816                 } else
2817                         retry = 1;
2818                 if (set_bad && test_bit(In_sync, &rdev->flags)
2819                     && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2820                         retry = 1;
2821                 if (retry)
2822                         if (sh->qd_idx >= 0 && sh->pd_idx == i)
2823                                 set_bit(R5_ReadError, &sh->dev[i].flags);
2824                         else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
2825                                 set_bit(R5_ReadError, &sh->dev[i].flags);
2826                                 clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2827                         } else
2828                                 set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2829                 else {
2830                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2831                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2832                         if (!(set_bad
2833                               && test_bit(In_sync, &rdev->flags)
2834                               && rdev_set_badblocks(
2835                                       rdev, sh->sector, RAID5_STRIPE_SECTORS(conf), 0)))
2836                                 md_error(conf->mddev, rdev);
2837                 }
2838         }
2839         rdev_dec_pending(rdev, conf->mddev);
2840         bio_uninit(bi);
2841         clear_bit(R5_LOCKED, &sh->dev[i].flags);
2842         set_bit(STRIPE_HANDLE, &sh->state);
2843         raid5_release_stripe(sh);
2844 }
2845
2846 static void raid5_end_write_request(struct bio *bi)
2847 {
2848         struct stripe_head *sh = bi->bi_private;
2849         struct r5conf *conf = sh->raid_conf;
2850         int disks = sh->disks, i;
2851         struct md_rdev *rdev;
2852         int replacement = 0;
2853
2854         for (i = 0 ; i < disks; i++) {
2855                 if (bi == &sh->dev[i].req) {
2856                         rdev = conf->disks[i].rdev;
2857                         break;
2858                 }
2859                 if (bi == &sh->dev[i].rreq) {
2860                         rdev = conf->disks[i].replacement;
2861                         if (rdev)
2862                                 replacement = 1;
2863                         else
2864                                 /* rdev was removed and 'replacement'
2865                                  * replaced it.  rdev is not removed
2866                                  * until all requests are finished.
2867                                  */
2868                                 rdev = conf->disks[i].rdev;
2869                         break;
2870                 }
2871         }
2872         pr_debug("end_write_request %llu/%d, count %d, error: %d.\n",
2873                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2874                 bi->bi_status);
2875         if (i == disks) {
2876                 BUG();
2877                 return;
2878         }
2879
2880         if (replacement) {
2881                 if (bi->bi_status)
2882                         md_error(conf->mddev, rdev);
2883                 else if (rdev_has_badblock(rdev, sh->sector,
2884                                            RAID5_STRIPE_SECTORS(conf)))
2885                         set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
2886         } else {
2887                 if (bi->bi_status) {
2888                         set_bit(STRIPE_DEGRADED, &sh->state);
2889                         set_bit(WriteErrorSeen, &rdev->flags);
2890                         set_bit(R5_WriteError, &sh->dev[i].flags);
2891                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
2892                                 set_bit(MD_RECOVERY_NEEDED,
2893                                         &rdev->mddev->recovery);
2894                 } else if (rdev_has_badblock(rdev, sh->sector,
2895                                              RAID5_STRIPE_SECTORS(conf))) {
2896                         set_bit(R5_MadeGood, &sh->dev[i].flags);
2897                         if (test_bit(R5_ReadError, &sh->dev[i].flags))
2898                                 /* That was a successful write so make
2899                                  * sure it looks like we already did
2900                                  * a re-write.
2901                                  */
2902                                 set_bit(R5_ReWrite, &sh->dev[i].flags);
2903                 }
2904         }
2905         rdev_dec_pending(rdev, conf->mddev);
2906
2907         if (sh->batch_head && bi->bi_status && !replacement)
2908                 set_bit(STRIPE_BATCH_ERR, &sh->batch_head->state);
2909
2910         bio_uninit(bi);
2911         if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
2912                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
2913         set_bit(STRIPE_HANDLE, &sh->state);
2914
2915         if (sh->batch_head && sh != sh->batch_head)
2916                 raid5_release_stripe(sh->batch_head);
2917         raid5_release_stripe(sh);
2918 }
2919
2920 static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
2921 {
2922         struct r5conf *conf = mddev->private;
2923         unsigned long flags;
2924         pr_debug("raid456: error called\n");
2925
2926         pr_crit("md/raid:%s: Disk failure on %pg, disabling device.\n",
2927                 mdname(mddev), rdev->bdev);
2928
2929         spin_lock_irqsave(&conf->device_lock, flags);
2930         set_bit(Faulty, &rdev->flags);
2931         clear_bit(In_sync, &rdev->flags);
2932         mddev->degraded = raid5_calc_degraded(conf);
2933
2934         if (has_failed(conf)) {
2935                 set_bit(MD_BROKEN, &conf->mddev->flags);
2936                 conf->recovery_disabled = mddev->recovery_disabled;
2937
2938                 pr_crit("md/raid:%s: Cannot continue operation (%d/%d failed).\n",
2939                         mdname(mddev), mddev->degraded, conf->raid_disks);
2940         } else {
2941                 pr_crit("md/raid:%s: Operation continuing on %d devices.\n",
2942                         mdname(mddev), conf->raid_disks - mddev->degraded);
2943         }
2944
2945         spin_unlock_irqrestore(&conf->device_lock, flags);
2946         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2947
2948         set_bit(Blocked, &rdev->flags);
2949         set_mask_bits(&mddev->sb_flags, 0,
2950                       BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
2951         r5c_update_on_rdev_error(mddev, rdev);
2952 }
2953
2954 /*
2955  * Input: a 'big' sector number,
2956  * Output: index of the data and parity disk, and the sector # in them.
2957  */
2958 sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
2959                               int previous, int *dd_idx,
2960                               struct stripe_head *sh)
2961 {
2962         sector_t stripe, stripe2;
2963         sector_t chunk_number;
2964         unsigned int chunk_offset;
2965         int pd_idx, qd_idx;
2966         int ddf_layout = 0;
2967         sector_t new_sector;
2968         int algorithm = previous ? conf->prev_algo
2969                                  : conf->algorithm;
2970         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2971                                          : conf->chunk_sectors;
2972         int raid_disks = previous ? conf->previous_raid_disks
2973                                   : conf->raid_disks;
2974         int data_disks = raid_disks - conf->max_degraded;
2975
2976         /* First compute the information on this sector */
2977
2978         /*
2979          * Compute the chunk number and the sector offset inside the chunk
2980          */
2981         chunk_offset = sector_div(r_sector, sectors_per_chunk);
2982         chunk_number = r_sector;
2983
2984         /*
2985          * Compute the stripe number
2986          */
2987         stripe = chunk_number;
2988         *dd_idx = sector_div(stripe, data_disks);
2989         stripe2 = stripe;
2990         /*
2991          * Select the parity disk based on the user selected algorithm.
2992          */
2993         pd_idx = qd_idx = -1;
2994         switch(conf->level) {
2995         case 4:
2996                 pd_idx = data_disks;
2997                 break;
2998         case 5:
2999                 switch (algorithm) {
3000                 case ALGORITHM_LEFT_ASYMMETRIC:
3001                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
3002                         if (*dd_idx >= pd_idx)
3003                                 (*dd_idx)++;
3004                         break;
3005                 case ALGORITHM_RIGHT_ASYMMETRIC:
3006                         pd_idx = sector_div(stripe2, raid_disks);
3007                         if (*dd_idx >= pd_idx)
3008                                 (*dd_idx)++;
3009                         break;
3010                 case ALGORITHM_LEFT_SYMMETRIC:
3011                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
3012                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
3013                         break;
3014                 case ALGORITHM_RIGHT_SYMMETRIC:
3015                         pd_idx = sector_div(stripe2, raid_disks);
3016                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
3017                         break;
3018                 case ALGORITHM_PARITY_0:
3019                         pd_idx = 0;
3020                         (*dd_idx)++;
3021                         break;
3022                 case ALGORITHM_PARITY_N:
3023                         pd_idx = data_disks;
3024                         break;
3025                 default:
3026                         BUG();
3027                 }
3028                 break;
3029         case 6:
3030
3031                 switch (algorithm) {
3032                 case ALGORITHM_LEFT_ASYMMETRIC:
3033                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3034                         qd_idx = pd_idx + 1;
3035                         if (pd_idx == raid_disks-1) {
3036                                 (*dd_idx)++;    /* Q D D D P */
3037                                 qd_idx = 0;
3038                         } else if (*dd_idx >= pd_idx)
3039                                 (*dd_idx) += 2; /* D D P Q D */
3040                         break;
3041                 case ALGORITHM_RIGHT_ASYMMETRIC:
3042                         pd_idx = sector_div(stripe2, raid_disks);
3043                         qd_idx = pd_idx + 1;
3044                         if (pd_idx == raid_disks-1) {
3045                                 (*dd_idx)++;    /* Q D D D P */
3046                                 qd_idx = 0;
3047                         } else if (*dd_idx >= pd_idx)
3048                                 (*dd_idx) += 2; /* D D P Q D */
3049                         break;
3050                 case ALGORITHM_LEFT_SYMMETRIC:
3051                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3052                         qd_idx = (pd_idx + 1) % raid_disks;
3053                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
3054                         break;
3055                 case ALGORITHM_RIGHT_SYMMETRIC:
3056                         pd_idx = sector_div(stripe2, raid_disks);
3057                         qd_idx = (pd_idx + 1) % raid_disks;
3058                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
3059                         break;
3060
3061                 case ALGORITHM_PARITY_0:
3062                         pd_idx = 0;
3063                         qd_idx = 1;
3064                         (*dd_idx) += 2;
3065                         break;
3066                 case ALGORITHM_PARITY_N:
3067                         pd_idx = data_disks;
3068                         qd_idx = data_disks + 1;
3069                         break;
3070
3071                 case ALGORITHM_ROTATING_ZERO_RESTART:
3072                         /* Exactly the same as RIGHT_ASYMMETRIC, but or
3073                          * of blocks for computing Q is different.
3074                          */
3075                         pd_idx = sector_div(stripe2, raid_disks);
3076                         qd_idx = pd_idx + 1;
3077                         if (pd_idx == raid_disks-1) {
3078                                 (*dd_idx)++;    /* Q D D D P */
3079                                 qd_idx = 0;
3080                         } else if (*dd_idx >= pd_idx)
3081                                 (*dd_idx) += 2; /* D D P Q D */
3082                         ddf_layout = 1;
3083                         break;
3084
3085                 case ALGORITHM_ROTATING_N_RESTART:
3086                         /* Same a left_asymmetric, by first stripe is
3087                          * D D D P Q  rather than
3088                          * Q D D D P
3089                          */
3090                         stripe2 += 1;
3091                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3092                         qd_idx = pd_idx + 1;
3093                         if (pd_idx == raid_disks-1) {
3094                                 (*dd_idx)++;    /* Q D D D P */
3095                                 qd_idx = 0;
3096                         } else if (*dd_idx >= pd_idx)
3097                                 (*dd_idx) += 2; /* D D P Q D */
3098                         ddf_layout = 1;
3099                         break;
3100
3101                 case ALGORITHM_ROTATING_N_CONTINUE:
3102                         /* Same as left_symmetric but Q is before P */
3103                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3104                         qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
3105                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
3106                         ddf_layout = 1;
3107                         break;
3108
3109                 case ALGORITHM_LEFT_ASYMMETRIC_6:
3110                         /* RAID5 left_asymmetric, with Q on last device */
3111                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
3112                         if (*dd_idx >= pd_idx)
3113                                 (*dd_idx)++;
3114                         qd_idx = raid_disks - 1;
3115                         break;
3116
3117                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
3118                         pd_idx = sector_div(stripe2, raid_disks-1);
3119                         if (*dd_idx >= pd_idx)
3120                                 (*dd_idx)++;
3121                         qd_idx = raid_disks - 1;
3122                         break;
3123
3124                 case ALGORITHM_LEFT_SYMMETRIC_6:
3125                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
3126                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
3127                         qd_idx = raid_disks - 1;
3128                         break;
3129
3130                 case ALGORITHM_RIGHT_SYMMETRIC_6:
3131                         pd_idx = sector_div(stripe2, raid_disks-1);
3132                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
3133                         qd_idx = raid_disks - 1;
3134                         break;
3135
3136                 case ALGORITHM_PARITY_0_6:
3137                         pd_idx = 0;
3138                         (*dd_idx)++;
3139                         qd_idx = raid_disks - 1;
3140                         break;
3141
3142                 default:
3143                         BUG();
3144                 }
3145                 break;
3146         }
3147
3148         if (sh) {
3149                 sh->pd_idx = pd_idx;
3150                 sh->qd_idx = qd_idx;
3151                 sh->ddf_layout = ddf_layout;
3152         }
3153         /*
3154          * Finally, compute the new sector number
3155          */
3156         new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
3157         return new_sector;
3158 }
3159
3160 sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous)
3161 {
3162         struct r5conf *conf = sh->raid_conf;
3163         int raid_disks = sh->disks;
3164         int data_disks = raid_disks - conf->max_degraded;
3165         sector_t new_sector = sh->sector, check;
3166         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
3167                                          : conf->chunk_sectors;
3168         int algorithm = previous ? conf->prev_algo
3169                                  : conf->algorithm;
3170         sector_t stripe;
3171         int chunk_offset;
3172         sector_t chunk_number;
3173         int dummy1, dd_idx = i;
3174         sector_t r_sector;
3175         struct stripe_head sh2;
3176
3177         chunk_offset = sector_div(new_sector, sectors_per_chunk);
3178         stripe = new_sector;
3179
3180         if (i == sh->pd_idx)
3181                 return 0;
3182         switch(conf->level) {
3183         case 4: break;
3184         case 5:
3185                 switch (algorithm) {
3186                 case ALGORITHM_LEFT_ASYMMETRIC:
3187                 case ALGORITHM_RIGHT_ASYMMETRIC:
3188                         if (i > sh->pd_idx)
3189                                 i--;
3190                         break;
3191                 case ALGORITHM_LEFT_SYMMETRIC:
3192                 case ALGORITHM_RIGHT_SYMMETRIC:
3193                         if (i < sh->pd_idx)
3194                                 i += raid_disks;
3195                         i -= (sh->pd_idx + 1);
3196                         break;
3197                 case ALGORITHM_PARITY_0:
3198                         i -= 1;
3199                         break;
3200                 case ALGORITHM_PARITY_N:
3201                         break;
3202                 default:
3203                         BUG();
3204                 }
3205                 break;
3206         case 6:
3207                 if (i == sh->qd_idx)
3208                         return 0; /* It is the Q disk */
3209                 switch (algorithm) {
3210                 case ALGORITHM_LEFT_ASYMMETRIC:
3211                 case ALGORITHM_RIGHT_ASYMMETRIC:
3212                 case ALGORITHM_ROTATING_ZERO_RESTART:
3213                 case ALGORITHM_ROTATING_N_RESTART:
3214                         if (sh->pd_idx == raid_disks-1)
3215                                 i--;    /* Q D D D P */
3216                         else if (i > sh->pd_idx)
3217                                 i -= 2; /* D D P Q D */
3218                         break;
3219                 case ALGORITHM_LEFT_SYMMETRIC:
3220                 case ALGORITHM_RIGHT_SYMMETRIC:
3221                         if (sh->pd_idx == raid_disks-1)
3222                                 i--; /* Q D D D P */
3223                         else {
3224                                 /* D D P Q D */
3225                                 if (i < sh->pd_idx)
3226                                         i += raid_disks;
3227                                 i -= (sh->pd_idx + 2);
3228                         }
3229                         break;
3230                 case ALGORITHM_PARITY_0:
3231                         i -= 2;
3232                         break;
3233                 case ALGORITHM_PARITY_N:
3234                         break;
3235                 case ALGORITHM_ROTATING_N_CONTINUE:
3236                         /* Like left_symmetric, but P is before Q */
3237                         if (sh->pd_idx == 0)
3238                                 i--;    /* P D D D Q */
3239                         else {
3240                                 /* D D Q P D */
3241                                 if (i < sh->pd_idx)
3242                                         i += raid_disks;
3243                                 i -= (sh->pd_idx + 1);
3244                         }
3245                         break;
3246                 case ALGORITHM_LEFT_ASYMMETRIC_6:
3247                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
3248                         if (i > sh->pd_idx)
3249                                 i--;
3250                         break;
3251                 case ALGORITHM_LEFT_SYMMETRIC_6:
3252                 case ALGORITHM_RIGHT_SYMMETRIC_6:
3253                         if (i < sh->pd_idx)
3254                                 i += data_disks + 1;
3255                         i -= (sh->pd_idx + 1);
3256                         break;
3257                 case ALGORITHM_PARITY_0_6:
3258                         i -= 1;
3259                         break;
3260                 default:
3261                         BUG();
3262                 }
3263                 break;
3264         }
3265
3266         chunk_number = stripe * data_disks + i;
3267         r_sector = chunk_number * sectors_per_chunk + chunk_offset;
3268
3269         check = raid5_compute_sector(conf, r_sector,
3270                                      previous, &dummy1, &sh2);
3271         if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
3272                 || sh2.qd_idx != sh->qd_idx) {
3273                 pr_warn("md/raid:%s: compute_blocknr: map not correct\n",
3274                         mdname(conf->mddev));
3275                 return 0;
3276         }
3277         return r_sector;
3278 }
3279
3280 /*
3281  * There are cases where we want handle_stripe_dirtying() and
3282  * schedule_reconstruction() to delay towrite to some dev of a stripe.
3283  *
3284  * This function checks whether we want to delay the towrite. Specifically,
3285  * we delay the towrite when:
3286  *
3287  *   1. degraded stripe has a non-overwrite to the missing dev, AND this
3288  *      stripe has data in journal (for other devices).
3289  *
3290  *      In this case, when reading data for the non-overwrite dev, it is
3291  *      necessary to handle complex rmw of write back cache (prexor with
3292  *      orig_page, and xor with page). To keep read path simple, we would
3293  *      like to flush data in journal to RAID disks first, so complex rmw
3294  *      is handled in the write patch (handle_stripe_dirtying).
3295  *
3296  *   2. when journal space is critical (R5C_LOG_CRITICAL=1)
3297  *
3298  *      It is important to be able to flush all stripes in raid5-cache.
3299  *      Therefore, we need reserve some space on the journal device for
3300  *      these flushes. If flush operation includes pending writes to the
3301  *      stripe, we need to reserve (conf->raid_disk + 1) pages per stripe
3302  *      for the flush out. If we exclude these pending writes from flush
3303  *      operation, we only need (conf->max_degraded + 1) pages per stripe.
3304  *      Therefore, excluding pending writes in these cases enables more
3305  *      efficient use of the journal device.
3306  *
3307  *      Note: To make sure the stripe makes progress, we only delay
3308  *      towrite for stripes with data already in journal (injournal > 0).
3309  *      When LOG_CRITICAL, stripes with injournal == 0 will be sent to
3310  *      no_space_stripes list.
3311  *
3312  *   3. during journal failure
3313  *      In journal failure, we try to flush all cached data to raid disks
3314  *      based on data in stripe cache. The array is read-only to upper
3315  *      layers, so we would skip all pending writes.
3316  *
3317  */
3318 static inline bool delay_towrite(struct r5conf *conf,
3319                                  struct r5dev *dev,
3320                                  struct stripe_head_state *s)
3321 {
3322         /* case 1 above */
3323         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3324             !test_bit(R5_Insync, &dev->flags) && s->injournal)
3325                 return true;
3326         /* case 2 above */
3327         if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
3328             s->injournal > 0)
3329                 return true;
3330         /* case 3 above */
3331         if (s->log_failed && s->injournal)
3332                 return true;
3333         return false;
3334 }
3335
3336 static void
3337 schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
3338                          int rcw, int expand)
3339 {
3340         int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx, disks = sh->disks;
3341         struct r5conf *conf = sh->raid_conf;
3342         int level = conf->level;
3343
3344         if (rcw) {
3345                 /*
3346                  * In some cases, handle_stripe_dirtying initially decided to
3347                  * run rmw and allocates extra page for prexor. However, rcw is
3348                  * cheaper later on. We need to free the extra page now,
3349                  * because we won't be able to do that in ops_complete_prexor().
3350                  */
3351                 r5c_release_extra_page(sh);
3352
3353                 for (i = disks; i--; ) {
3354                         struct r5dev *dev = &sh->dev[i];
3355
3356                         if (dev->towrite && !delay_towrite(conf, dev, s)) {
3357                                 set_bit(R5_LOCKED, &dev->flags);
3358                                 set_bit(R5_Wantdrain, &dev->flags);
3359                                 if (!expand)
3360                                         clear_bit(R5_UPTODATE, &dev->flags);
3361                                 s->locked++;
3362                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3363                                 set_bit(R5_LOCKED, &dev->flags);
3364                                 s->locked++;
3365                         }
3366                 }
3367                 /* if we are not expanding this is a proper write request, and
3368                  * there will be bios with new data to be drained into the
3369                  * stripe cache
3370                  */
3371                 if (!expand) {
3372                         if (!s->locked)
3373                                 /* False alarm, nothing to do */
3374                                 return;
3375                         sh->reconstruct_state = reconstruct_state_drain_run;
3376                         set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3377                 } else
3378                         sh->reconstruct_state = reconstruct_state_run;
3379
3380                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3381
3382                 if (s->locked + conf->max_degraded == disks)
3383                         if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
3384                                 atomic_inc(&conf->pending_full_writes);
3385         } else {
3386                 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
3387                         test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
3388                 BUG_ON(level == 6 &&
3389                         (!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
3390                            test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));
3391
3392                 for (i = disks; i--; ) {
3393                         struct r5dev *dev = &sh->dev[i];
3394                         if (i == pd_idx || i == qd_idx)
3395                                 continue;
3396
3397                         if (dev->towrite &&
3398                             (test_bit(R5_UPTODATE, &dev->flags) ||
3399                              test_bit(R5_Wantcompute, &dev->flags))) {
3400                                 set_bit(R5_Wantdrain, &dev->flags);
3401                                 set_bit(R5_LOCKED, &dev->flags);
3402                                 clear_bit(R5_UPTODATE, &dev->flags);
3403                                 s->locked++;
3404                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3405                                 set_bit(R5_LOCKED, &dev->flags);
3406                                 s->locked++;
3407                         }
3408                 }
3409                 if (!s->locked)
3410                         /* False alarm - nothing to do */
3411                         return;
3412                 sh->reconstruct_state = reconstruct_state_prexor_drain_run;
3413                 set_bit(STRIPE_OP_PREXOR, &s->ops_request);
3414                 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3415                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3416         }
3417
3418         /* keep the parity disk(s) locked while asynchronous operations
3419          * are in flight
3420          */
3421         set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
3422         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
3423         s->locked++;
3424
3425         if (level == 6) {
3426                 int qd_idx = sh->qd_idx;
3427                 struct r5dev *dev = &sh->dev[qd_idx];
3428
3429                 set_bit(R5_LOCKED, &dev->flags);
3430                 clear_bit(R5_UPTODATE, &dev->flags);
3431                 s->locked++;
3432         }
3433
3434         if (raid5_has_ppl(sh->raid_conf) && sh->ppl_page &&
3435             test_bit(STRIPE_OP_BIODRAIN, &s->ops_request) &&
3436             !test_bit(STRIPE_FULL_WRITE, &sh->state) &&
3437             test_bit(R5_Insync, &sh->dev[pd_idx].flags))
3438                 set_bit(STRIPE_OP_PARTIAL_PARITY, &s->ops_request);
3439
3440         pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
3441                 __func__, (unsigned long long)sh->sector,
3442                 s->locked, s->ops_request);
3443 }
3444
3445 static bool stripe_bio_overlaps(struct stripe_head *sh, struct bio *bi,
3446                                 int dd_idx, int forwrite)
3447 {
3448         struct r5conf *conf = sh->raid_conf;
3449         struct bio **bip;
3450
3451         pr_debug("checking bi b#%llu to stripe s#%llu\n",
3452                  bi->bi_iter.bi_sector, sh->sector);
3453
3454         /* Don't allow new IO added to stripes in batch list */
3455         if (sh->batch_head)
3456                 return true;
3457
3458         if (forwrite)
3459                 bip = &sh->dev[dd_idx].towrite;
3460         else
3461                 bip = &sh->dev[dd_idx].toread;
3462
3463         while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector) {
3464                 if (bio_end_sector(*bip) > bi->bi_iter.bi_sector)
3465                         return true;
3466                 bip = &(*bip)->bi_next;
3467         }
3468
3469         if (*bip && (*bip)->bi_iter.bi_sector < bio_end_sector(bi))
3470                 return true;
3471
3472         if (forwrite && raid5_has_ppl(conf)) {
3473                 /*
3474                  * With PPL only writes to consecutive data chunks within a
3475                  * stripe are allowed because for a single stripe_head we can
3476                  * only have one PPL entry at a time, which describes one data
3477                  * range. Not really an overlap, but wait_for_overlap can be
3478                  * used to handle this.
3479                  */
3480                 sector_t sector;
3481                 sector_t first = 0;
3482                 sector_t last = 0;
3483                 int count = 0;
3484                 int i;
3485
3486                 for (i = 0; i < sh->disks; i++) {
3487                         if (i != sh->pd_idx &&
3488                             (i == dd_idx || sh->dev[i].towrite)) {
3489                                 sector = sh->dev[i].sector;
3490                                 if (count == 0 || sector < first)
3491                                         first = sector;
3492                                 if (sector > last)
3493                                         last = sector;
3494                                 count++;
3495                         }
3496                 }
3497
3498                 if (first + conf->chunk_sectors * (count - 1) != last)
3499                         return true;
3500         }
3501
3502         return false;
3503 }
3504
3505 static void __add_stripe_bio(struct stripe_head *sh, struct bio *bi,
3506                              int dd_idx, int forwrite, int previous)
3507 {
3508         struct r5conf *conf = sh->raid_conf;
3509         struct bio **bip;
3510         int firstwrite = 0;
3511
3512         if (forwrite) {
3513                 bip = &sh->dev[dd_idx].towrite;
3514                 if (!*bip)
3515                         firstwrite = 1;
3516         } else {
3517                 bip = &sh->dev[dd_idx].toread;
3518         }
3519
3520         while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector)
3521                 bip = &(*bip)->bi_next;
3522
3523         if (!forwrite || previous)
3524                 clear_bit(STRIPE_BATCH_READY, &sh->state);
3525
3526         BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
3527         if (*bip)
3528                 bi->bi_next = *bip;
3529         *bip = bi;
3530         bio_inc_remaining(bi);
3531         md_write_inc(conf->mddev, bi);
3532
3533         if (forwrite) {
3534                 /* check if page is covered */
3535                 sector_t sector = sh->dev[dd_idx].sector;
3536                 for (bi=sh->dev[dd_idx].towrite;
3537                      sector < sh->dev[dd_idx].sector + RAID5_STRIPE_SECTORS(conf) &&
3538                              bi && bi->bi_iter.bi_sector <= sector;
3539                      bi = r5_next_bio(conf, bi, sh->dev[dd_idx].sector)) {
3540                         if (bio_end_sector(bi) >= sector)
3541                                 sector = bio_end_sector(bi);
3542                 }
3543                 if (sector >= sh->dev[dd_idx].sector + RAID5_STRIPE_SECTORS(conf))
3544                         if (!test_and_set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags))
3545                                 sh->overwrite_disks++;
3546         }
3547
3548         pr_debug("added bi b#%llu to stripe s#%llu, disk %d, logical %llu\n",
3549                  (*bip)->bi_iter.bi_sector, sh->sector, dd_idx,
3550                  sh->dev[dd_idx].sector);
3551
3552         if (conf->mddev->bitmap && firstwrite) {
3553                 /* Cannot hold spinlock over bitmap_startwrite,
3554                  * but must ensure this isn't added to a batch until
3555                  * we have added to the bitmap and set bm_seq.
3556                  * So set STRIPE_BITMAP_PENDING to prevent
3557                  * batching.
3558                  * If multiple __add_stripe_bio() calls race here they
3559                  * much all set STRIPE_BITMAP_PENDING.  So only the first one
3560                  * to complete "bitmap_startwrite" gets to set
3561                  * STRIPE_BIT_DELAY.  This is important as once a stripe
3562                  * is added to a batch, STRIPE_BIT_DELAY cannot be changed
3563                  * any more.
3564                  */
3565                 set_bit(STRIPE_BITMAP_PENDING, &sh->state);
3566                 spin_unlock_irq(&sh->stripe_lock);
3567                 md_bitmap_startwrite(conf->mddev->bitmap, sh->sector,
3568                                      RAID5_STRIPE_SECTORS(conf), 0);
3569                 spin_lock_irq(&sh->stripe_lock);
3570                 clear_bit(STRIPE_BITMAP_PENDING, &sh->state);
3571                 if (!sh->batch_head) {
3572                         sh->bm_seq = conf->seq_flush+1;
3573                         set_bit(STRIPE_BIT_DELAY, &sh->state);
3574                 }
3575         }
3576 }
3577
3578 /*
3579  * Each stripe/dev can have one or more bios attached.
3580  * toread/towrite point to the first in a chain.
3581  * The bi_next chain must be in order.
3582  */
3583 static bool add_stripe_bio(struct stripe_head *sh, struct bio *bi,
3584                            int dd_idx, int forwrite, int previous)
3585 {
3586         spin_lock_irq(&sh->stripe_lock);
3587
3588         if (stripe_bio_overlaps(sh, bi, dd_idx, forwrite)) {
3589                 set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
3590                 spin_unlock_irq(&sh->stripe_lock);
3591                 return false;
3592         }
3593
3594         __add_stripe_bio(sh, bi, dd_idx, forwrite, previous);
3595         spin_unlock_irq(&sh->stripe_lock);
3596         return true;
3597 }
3598
3599 static void end_reshape(struct r5conf *conf);
3600
3601 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
3602                             struct stripe_head *sh)
3603 {
3604         int sectors_per_chunk =
3605                 previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
3606         int dd_idx;
3607         int chunk_offset = sector_div(stripe, sectors_per_chunk);
3608         int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
3609
3610         raid5_compute_sector(conf,
3611                              stripe * (disks - conf->max_degraded)
3612                              *sectors_per_chunk + chunk_offset,
3613                              previous,
3614                              &dd_idx, sh);
3615 }
3616
3617 static void
3618 handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
3619                      struct stripe_head_state *s, int disks)
3620 {
3621         int i;
3622         BUG_ON(sh->batch_head);
3623         for (i = disks; i--; ) {
3624                 struct bio *bi;
3625                 int bitmap_end = 0;
3626
3627                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
3628                         struct md_rdev *rdev = conf->disks[i].rdev;
3629
3630                         if (rdev && test_bit(In_sync, &rdev->flags) &&
3631                             !test_bit(Faulty, &rdev->flags))
3632                                 atomic_inc(&rdev->nr_pending);
3633                         else
3634                                 rdev = NULL;
3635                         if (rdev) {
3636                                 if (!rdev_set_badblocks(
3637                                             rdev,
3638                                             sh->sector,
3639                                             RAID5_STRIPE_SECTORS(conf), 0))
3640                                         md_error(conf->mddev, rdev);
3641                                 rdev_dec_pending(rdev, conf->mddev);
3642                         }
3643                 }
3644                 spin_lock_irq(&sh->stripe_lock);
3645                 /* fail all writes first */
3646                 bi = sh->dev[i].towrite;
3647                 sh->dev[i].towrite = NULL;
3648                 sh->overwrite_disks = 0;
3649                 spin_unlock_irq(&sh->stripe_lock);
3650                 if (bi)
3651                         bitmap_end = 1;
3652
3653                 log_stripe_write_finished(sh);
3654
3655                 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3656                         wake_up(&conf->wait_for_overlap);
3657
3658                 while (bi && bi->bi_iter.bi_sector <
3659                         sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3660                         struct bio *nextbi = r5_next_bio(conf, bi, sh->dev[i].sector);
3661
3662                         md_write_end(conf->mddev);
3663                         bio_io_error(bi);
3664                         bi = nextbi;
3665                 }
3666                 if (bitmap_end)
3667                         md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3668                                            RAID5_STRIPE_SECTORS(conf), 0, 0);
3669                 bitmap_end = 0;
3670                 /* and fail all 'written' */
3671                 bi = sh->dev[i].written;
3672                 sh->dev[i].written = NULL;
3673                 if (test_and_clear_bit(R5_SkipCopy, &sh->dev[i].flags)) {
3674                         WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
3675                         sh->dev[i].page = sh->dev[i].orig_page;
3676                 }
3677
3678                 if (bi) bitmap_end = 1;
3679                 while (bi && bi->bi_iter.bi_sector <
3680                        sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3681                         struct bio *bi2 = r5_next_bio(conf, bi, sh->dev[i].sector);
3682
3683                         md_write_end(conf->mddev);
3684                         bio_io_error(bi);
3685                         bi = bi2;
3686                 }
3687
3688                 /* fail any reads if this device is non-operational and
3689                  * the data has not reached the cache yet.
3690                  */
3691                 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
3692                     s->failed > conf->max_degraded &&
3693                     (!test_bit(R5_Insync, &sh->dev[i].flags) ||
3694                       test_bit(R5_ReadError, &sh->dev[i].flags))) {
3695                         spin_lock_irq(&sh->stripe_lock);
3696                         bi = sh->dev[i].toread;
3697                         sh->dev[i].toread = NULL;
3698                         spin_unlock_irq(&sh->stripe_lock);
3699                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3700                                 wake_up(&conf->wait_for_overlap);
3701                         if (bi)
3702                                 s->to_read--;
3703                         while (bi && bi->bi_iter.bi_sector <
3704                                sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3705                                 struct bio *nextbi =
3706                                         r5_next_bio(conf, bi, sh->dev[i].sector);
3707
3708                                 bio_io_error(bi);
3709                                 bi = nextbi;
3710                         }
3711                 }
3712                 if (bitmap_end)
3713                         md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3714                                            RAID5_STRIPE_SECTORS(conf), 0, 0);
3715                 /* If we were in the middle of a write the parity block might
3716                  * still be locked - so just clear all R5_LOCKED flags
3717                  */
3718                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
3719         }
3720         s->to_write = 0;
3721         s->written = 0;
3722
3723         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3724                 if (atomic_dec_and_test(&conf->pending_full_writes))
3725                         md_wakeup_thread(conf->mddev->thread);
3726 }
3727
3728 static void
3729 handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
3730                    struct stripe_head_state *s)
3731 {
3732         int abort = 0;
3733         int i;
3734
3735         BUG_ON(sh->batch_head);
3736         clear_bit(STRIPE_SYNCING, &sh->state);
3737         if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
3738                 wake_up(&conf->wait_for_overlap);
3739         s->syncing = 0;
3740         s->replacing = 0;
3741         /* There is nothing more to do for sync/check/repair.
3742          * Don't even need to abort as that is handled elsewhere
3743          * if needed, and not always wanted e.g. if there is a known
3744          * bad block here.
3745          * For recover/replace we need to record a bad block on all
3746          * non-sync devices, or abort the recovery
3747          */
3748         if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
3749                 /* During recovery devices cannot be removed, so
3750                  * locking and refcounting of rdevs is not needed
3751                  */
3752                 for (i = 0; i < conf->raid_disks; i++) {
3753                         struct md_rdev *rdev = conf->disks[i].rdev;
3754
3755                         if (rdev
3756                             && !test_bit(Faulty, &rdev->flags)
3757                             && !test_bit(In_sync, &rdev->flags)
3758                             && !rdev_set_badblocks(rdev, sh->sector,
3759                                                    RAID5_STRIPE_SECTORS(conf), 0))
3760                                 abort = 1;
3761                         rdev = conf->disks[i].replacement;
3762
3763                         if (rdev
3764                             && !test_bit(Faulty, &rdev->flags)
3765                             && !test_bit(In_sync, &rdev->flags)
3766                             && !rdev_set_badblocks(rdev, sh->sector,
3767                                                    RAID5_STRIPE_SECTORS(conf), 0))
3768                                 abort = 1;
3769                 }
3770                 if (abort)
3771                         conf->recovery_disabled =
3772                                 conf->mddev->recovery_disabled;
3773         }
3774         md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), !abort);
3775 }
3776
3777 static int want_replace(struct stripe_head *sh, int disk_idx)
3778 {
3779         struct md_rdev *rdev;
3780         int rv = 0;
3781
3782         rdev = sh->raid_conf->disks[disk_idx].replacement;
3783         if (rdev
3784             && !test_bit(Faulty, &rdev->flags)
3785             && !test_bit(In_sync, &rdev->flags)
3786             && (rdev->recovery_offset <= sh->sector
3787                 || rdev->mddev->recovery_cp <= sh->sector))
3788                 rv = 1;
3789         return rv;
3790 }
3791
3792 static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
3793                            int disk_idx, int disks)
3794 {
3795         struct r5dev *dev = &sh->dev[disk_idx];
3796         struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
3797                                   &sh->dev[s->failed_num[1]] };
3798         int i;
3799         bool force_rcw = (sh->raid_conf->rmw_level == PARITY_DISABLE_RMW);
3800
3801
3802         if (test_bit(R5_LOCKED, &dev->flags) ||
3803             test_bit(R5_UPTODATE, &dev->flags))
3804                 /* No point reading this as we already have it or have
3805                  * decided to get it.
3806                  */
3807                 return 0;
3808
3809         if (dev->toread ||
3810             (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)))
3811                 /* We need this block to directly satisfy a request */
3812                 return 1;
3813
3814         if (s->syncing || s->expanding ||
3815             (s->replacing && want_replace(sh, disk_idx)))
3816                 /* When syncing, or expanding we read everything.
3817                  * When replacing, we need the replaced block.
3818                  */
3819                 return 1;
3820
3821         if ((s->failed >= 1 && fdev[0]->toread) ||
3822             (s->failed >= 2 && fdev[1]->toread))
3823                 /* If we want to read from a failed device, then
3824                  * we need to actually read every other device.
3825                  */
3826                 return 1;
3827
3828         /* Sometimes neither read-modify-write nor reconstruct-write
3829          * cycles can work.  In those cases we read every block we
3830          * can.  Then the parity-update is certain to have enough to
3831          * work with.
3832          * This can only be a problem when we need to write something,
3833          * and some device has failed.  If either of those tests
3834          * fail we need look no further.
3835          */
3836         if (!s->failed || !s->to_write)
3837                 return 0;
3838
3839         if (test_bit(R5_Insync, &dev->flags) &&
3840             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3841                 /* Pre-reads at not permitted until after short delay
3842                  * to gather multiple requests.  However if this
3843                  * device is no Insync, the block could only be computed
3844                  * and there is no need to delay that.
3845                  */
3846                 return 0;
3847
3848         for (i = 0; i < s->failed && i < 2; i++) {
3849                 if (fdev[i]->towrite &&
3850                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3851                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3852                         /* If we have a partial write to a failed
3853                          * device, then we will need to reconstruct
3854                          * the content of that device, so all other
3855                          * devices must be read.
3856                          */
3857                         return 1;
3858
3859                 if (s->failed >= 2 &&
3860                     (fdev[i]->towrite ||
3861                      s->failed_num[i] == sh->pd_idx ||
3862                      s->failed_num[i] == sh->qd_idx) &&
3863                     !test_bit(R5_UPTODATE, &fdev[i]->flags))
3864                         /* In max degraded raid6, If the failed disk is P, Q,
3865                          * or we want to read the failed disk, we need to do
3866                          * reconstruct-write.
3867                          */
3868                         force_rcw = true;
3869         }
3870
3871         /* If we are forced to do a reconstruct-write, because parity
3872          * cannot be trusted and we are currently recovering it, there
3873          * is extra need to be careful.
3874          * If one of the devices that we would need to read, because
3875          * it is not being overwritten (and maybe not written at all)
3876          * is missing/faulty, then we need to read everything we can.
3877          */
3878         if (!force_rcw &&
3879             sh->sector < sh->raid_conf->mddev->recovery_cp)
3880                 /* reconstruct-write isn't being forced */
3881                 return 0;
3882         for (i = 0; i < s->failed && i < 2; i++) {
3883                 if (s->failed_num[i] != sh->pd_idx &&
3884                     s->failed_num[i] != sh->qd_idx &&
3885                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3886                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3887                         return 1;
3888         }
3889
3890         return 0;
3891 }
3892
3893 /* fetch_block - checks the given member device to see if its data needs
3894  * to be read or computed to satisfy a request.
3895  *
3896  * Returns 1 when no more member devices need to be checked, otherwise returns
3897  * 0 to tell the loop in handle_stripe_fill to continue
3898  */
3899 static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
3900                        int disk_idx, int disks)
3901 {
3902         struct r5dev *dev = &sh->dev[disk_idx];
3903
3904         /* is the data in this block needed, and can we get it? */
3905         if (need_this_block(sh, s, disk_idx, disks)) {
3906                 /* we would like to get this block, possibly by computing it,
3907                  * otherwise read it if the backing disk is insync
3908                  */
3909                 BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
3910                 BUG_ON(test_bit(R5_Wantread, &dev->flags));
3911                 BUG_ON(sh->batch_head);
3912
3913                 /*
3914                  * In the raid6 case if the only non-uptodate disk is P
3915                  * then we already trusted P to compute the other failed
3916                  * drives. It is safe to compute rather than re-read P.
3917                  * In other cases we only compute blocks from failed
3918                  * devices, otherwise check/repair might fail to detect
3919                  * a real inconsistency.
3920                  */
3921
3922                 if ((s->uptodate == disks - 1) &&
3923                     ((sh->qd_idx >= 0 && sh->pd_idx == disk_idx) ||
3924                     (s->failed && (disk_idx == s->failed_num[0] ||
3925                                    disk_idx == s->failed_num[1])))) {
3926                         /* have disk failed, and we're requested to fetch it;
3927                          * do compute it
3928                          */
3929                         pr_debug("Computing stripe %llu block %d\n",
3930                                (unsigned long long)sh->sector, disk_idx);
3931                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3932                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3933                         set_bit(R5_Wantcompute, &dev->flags);
3934                         sh->ops.target = disk_idx;
3935                         sh->ops.target2 = -1; /* no 2nd target */
3936                         s->req_compute = 1;
3937                         /* Careful: from this point on 'uptodate' is in the eye
3938                          * of raid_run_ops which services 'compute' operations
3939                          * before writes. R5_Wantcompute flags a block that will
3940                          * be R5_UPTODATE by the time it is needed for a
3941                          * subsequent operation.
3942                          */
3943                         s->uptodate++;
3944                         return 1;
3945                 } else if (s->uptodate == disks-2 && s->failed >= 2) {
3946                         /* Computing 2-failure is *very* expensive; only
3947                          * do it if failed >= 2
3948                          */
3949                         int other;
3950                         for (other = disks; other--; ) {
3951                                 if (other == disk_idx)
3952                                         continue;
3953                                 if (!test_bit(R5_UPTODATE,
3954                                       &sh->dev[other].flags))
3955                                         break;
3956                         }
3957                         BUG_ON(other < 0);
3958                         pr_debug("Computing stripe %llu blocks %d,%d\n",
3959                                (unsigned long long)sh->sector,
3960                                disk_idx, other);
3961                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3962                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3963                         set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
3964                         set_bit(R5_Wantcompute, &sh->dev[other].flags);
3965                         sh->ops.target = disk_idx;
3966                         sh->ops.target2 = other;
3967                         s->uptodate += 2;
3968                         s->req_compute = 1;
3969                         return 1;
3970                 } else if (test_bit(R5_Insync, &dev->flags)) {
3971                         set_bit(R5_LOCKED, &dev->flags);
3972                         set_bit(R5_Wantread, &dev->flags);
3973                         s->locked++;
3974                         pr_debug("Reading block %d (sync=%d)\n",
3975                                 disk_idx, s->syncing);
3976                 }
3977         }
3978
3979         return 0;
3980 }
3981
3982 /*
3983  * handle_stripe_fill - read or compute data to satisfy pending requests.
3984  */
3985 static void handle_stripe_fill(struct stripe_head *sh,
3986                                struct stripe_head_state *s,
3987                                int disks)
3988 {
3989         int i;
3990
3991         /* look for blocks to read/compute, skip this if a compute
3992          * is already in flight, or if the stripe contents are in the
3993          * midst of changing due to a write
3994          */
3995         if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
3996             !sh->reconstruct_state) {
3997
3998                 /*
3999                  * For degraded stripe with data in journal, do not handle
4000                  * read requests yet, instead, flush the stripe to raid
4001                  * disks first, this avoids handling complex rmw of write
4002                  * back cache (prexor with orig_page, and then xor with
4003                  * page) in the read path
4004                  */
4005                 if (s->to_read && s->injournal && s->failed) {
4006                         if (test_bit(STRIPE_R5C_CACHING, &sh->state))
4007                                 r5c_make_stripe_write_out(sh);
4008                         goto out;
4009                 }
4010
4011                 for (i = disks; i--; )
4012                         if (fetch_block(sh, s, i, disks))
4013                                 break;
4014         }
4015 out:
4016         set_bit(STRIPE_HANDLE, &sh->state);
4017 }
4018
4019 static void break_stripe_batch_list(struct stripe_head *head_sh,
4020                                     unsigned long handle_flags);
4021 /* handle_stripe_clean_event
4022  * any written block on an uptodate or failed drive can be returned.
4023  * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
4024  * never LOCKED, so we don't need to test 'failed' directly.
4025  */
4026 static void handle_stripe_clean_event(struct r5conf *conf,
4027         struct stripe_head *sh, int disks)
4028 {
4029         int i;
4030         struct r5dev *dev;
4031         int discard_pending = 0;
4032         struct stripe_head *head_sh = sh;
4033         bool do_endio = false;
4034
4035         for (i = disks; i--; )
4036                 if (sh->dev[i].written) {
4037                         dev = &sh->dev[i];
4038                         if (!test_bit(R5_LOCKED, &dev->flags) &&
4039                             (test_bit(R5_UPTODATE, &dev->flags) ||
4040                              test_bit(R5_Discard, &dev->flags) ||
4041                              test_bit(R5_SkipCopy, &dev->flags))) {
4042                                 /* We can return any write requests */
4043                                 struct bio *wbi, *wbi2;
4044                                 pr_debug("Return write for disc %d\n", i);
4045                                 if (test_and_clear_bit(R5_Discard, &dev->flags))
4046                                         clear_bit(R5_UPTODATE, &dev->flags);
4047                                 if (test_and_clear_bit(R5_SkipCopy, &dev->flags)) {
4048                                         WARN_ON(test_bit(R5_UPTODATE, &dev->flags));
4049                                 }
4050                                 do_endio = true;
4051
4052 returnbi:
4053                                 dev->page = dev->orig_page;
4054                                 wbi = dev->written;
4055                                 dev->written = NULL;
4056                                 while (wbi && wbi->bi_iter.bi_sector <
4057                                         dev->sector + RAID5_STRIPE_SECTORS(conf)) {
4058                                         wbi2 = r5_next_bio(conf, wbi, dev->sector);
4059                                         md_write_end(conf->mddev);
4060                                         bio_endio(wbi);
4061                                         wbi = wbi2;
4062                                 }
4063                                 md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
4064                                                    RAID5_STRIPE_SECTORS(conf),
4065                                                    !test_bit(STRIPE_DEGRADED, &sh->state),
4066                                                    0);
4067                                 if (head_sh->batch_head) {
4068                                         sh = list_first_entry(&sh->batch_list,
4069                                                               struct stripe_head,
4070                                                               batch_list);
4071                                         if (sh != head_sh) {
4072                                                 dev = &sh->dev[i];
4073                                                 goto returnbi;
4074                                         }
4075                                 }
4076                                 sh = head_sh;
4077                                 dev = &sh->dev[i];
4078                         } else if (test_bit(R5_Discard, &dev->flags))
4079                                 discard_pending = 1;
4080                 }
4081
4082         log_stripe_write_finished(sh);
4083
4084         if (!discard_pending &&
4085             test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) {
4086                 int hash;
4087                 clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
4088                 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4089                 if (sh->qd_idx >= 0) {
4090                         clear_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
4091                         clear_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags);
4092                 }
4093                 /* now that discard is done we can proceed with any sync */
4094                 clear_bit(STRIPE_DISCARD, &sh->state);
4095                 /*
4096                  * SCSI discard will change some bio fields and the stripe has
4097                  * no updated data, so remove it from hash list and the stripe
4098                  * will be reinitialized
4099                  */
4100 unhash:
4101                 hash = sh->hash_lock_index;
4102                 spin_lock_irq(conf->hash_locks + hash);
4103                 remove_hash(sh);
4104                 spin_unlock_irq(conf->hash_locks + hash);
4105                 if (head_sh->batch_head) {
4106                         sh = list_first_entry(&sh->batch_list,
4107                                               struct stripe_head, batch_list);
4108                         if (sh != head_sh)
4109                                         goto unhash;
4110                 }
4111                 sh = head_sh;
4112
4113                 if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
4114                         set_bit(STRIPE_HANDLE, &sh->state);
4115
4116         }
4117
4118         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
4119                 if (atomic_dec_and_test(&conf->pending_full_writes))
4120                         md_wakeup_thread(conf->mddev->thread);
4121
4122         if (head_sh->batch_head && do_endio)
4123                 break_stripe_batch_list(head_sh, STRIPE_EXPAND_SYNC_FLAGS);
4124 }
4125
4126 /*
4127  * For RMW in write back cache, we need extra page in prexor to store the
4128  * old data. This page is stored in dev->orig_page.
4129  *
4130  * This function checks whether we have data for prexor. The exact logic
4131  * is:
4132  *       R5_UPTODATE && (!R5_InJournal || R5_OrigPageUPTDODATE)
4133  */
4134 static inline bool uptodate_for_rmw(struct r5dev *dev)
4135 {
4136         return (test_bit(R5_UPTODATE, &dev->flags)) &&
4137                 (!test_bit(R5_InJournal, &dev->flags) ||
4138                  test_bit(R5_OrigPageUPTDODATE, &dev->flags));
4139 }
4140
4141 static int handle_stripe_dirtying(struct r5conf *conf,
4142                                   struct stripe_head *sh,
4143                                   struct stripe_head_state *s,
4144                                   int disks)
4145 {
4146         int rmw = 0, rcw = 0, i;
4147         sector_t recovery_cp = conf->mddev->recovery_cp;
4148
4149         /* Check whether resync is now happening or should start.
4150          * If yes, then the array is dirty (after unclean shutdown or
4151          * initial creation), so parity in some stripes might be inconsistent.
4152          * In this case, we need to always do reconstruct-write, to ensure
4153          * that in case of drive failure or read-error correction, we
4154          * generate correct data from the parity.
4155          */
4156         if (conf->rmw_level == PARITY_DISABLE_RMW ||
4157             (recovery_cp < MaxSector && sh->sector >= recovery_cp &&
4158              s->failed == 0)) {
4159                 /* Calculate the real rcw later - for now make it
4160                  * look like rcw is cheaper
4161                  */
4162                 rcw = 1; rmw = 2;
4163                 pr_debug("force RCW rmw_level=%u, recovery_cp=%llu sh->sector=%llu\n",
4164                          conf->rmw_level, (unsigned long long)recovery_cp,
4165                          (unsigned long long)sh->sector);
4166         } else for (i = disks; i--; ) {
4167                 /* would I have to read this buffer for read_modify_write */
4168                 struct r5dev *dev = &sh->dev[i];
4169                 if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
4170                      i == sh->pd_idx || i == sh->qd_idx ||
4171                      test_bit(R5_InJournal, &dev->flags)) &&
4172                     !test_bit(R5_LOCKED, &dev->flags) &&
4173                     !(uptodate_for_rmw(dev) ||
4174                       test_bit(R5_Wantcompute, &dev->flags))) {
4175                         if (test_bit(R5_Insync, &dev->flags))
4176                                 rmw++;
4177                         else
4178                                 rmw += 2*disks;  /* cannot read it */
4179                 }
4180                 /* Would I have to read this buffer for reconstruct_write */
4181                 if (!test_bit(R5_OVERWRITE, &dev->flags) &&
4182                     i != sh->pd_idx && i != sh->qd_idx &&
4183                     !test_bit(R5_LOCKED, &dev->flags) &&
4184                     !(test_bit(R5_UPTODATE, &dev->flags) ||
4185                       test_bit(R5_Wantcompute, &dev->flags))) {
4186                         if (test_bit(R5_Insync, &dev->flags))
4187                                 rcw++;
4188                         else
4189                                 rcw += 2*disks;
4190                 }
4191         }
4192
4193         pr_debug("for sector %llu state 0x%lx, rmw=%d rcw=%d\n",
4194                  (unsigned long long)sh->sector, sh->state, rmw, rcw);
4195         set_bit(STRIPE_HANDLE, &sh->state);
4196         if ((rmw < rcw || (rmw == rcw && conf->rmw_level == PARITY_PREFER_RMW)) && rmw > 0) {
4197                 /* prefer read-modify-write, but need to get some data */
4198                 mddev_add_trace_msg(conf->mddev, "raid5 rmw %llu %d",
4199                                 sh->sector, rmw);
4200
4201                 for (i = disks; i--; ) {
4202                         struct r5dev *dev = &sh->dev[i];
4203                         if (test_bit(R5_InJournal, &dev->flags) &&
4204                             dev->page == dev->orig_page &&
4205                             !test_bit(R5_LOCKED, &sh->dev[sh->pd_idx].flags)) {
4206                                 /* alloc page for prexor */
4207                                 struct page *p = alloc_page(GFP_NOIO);
4208
4209                                 if (p) {
4210                                         dev->orig_page = p;
4211                                         continue;
4212                                 }
4213
4214                                 /*
4215                                  * alloc_page() failed, try use
4216                                  * disk_info->extra_page
4217                                  */
4218                                 if (!test_and_set_bit(R5C_EXTRA_PAGE_IN_USE,
4219                                                       &conf->cache_state)) {
4220                                         r5c_use_extra_page(sh);
4221                                         break;
4222                                 }
4223
4224                                 /* extra_page in use, add to delayed_list */
4225                                 set_bit(STRIPE_DELAYED, &sh->state);
4226                                 s->waiting_extra_page = 1;
4227                                 return -EAGAIN;
4228                         }
4229                 }
4230
4231                 for (i = disks; i--; ) {
4232                         struct r5dev *dev = &sh->dev[i];
4233                         if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
4234                              i == sh->pd_idx || i == sh->qd_idx ||
4235                              test_bit(R5_InJournal, &dev->flags)) &&
4236                             !test_bit(R5_LOCKED, &dev->flags) &&
4237                             !(uptodate_for_rmw(dev) ||
4238                               test_bit(R5_Wantcompute, &dev->flags)) &&
4239                             test_bit(R5_Insync, &dev->flags)) {
4240                                 if (test_bit(STRIPE_PREREAD_ACTIVE,
4241                                              &sh->state)) {
4242                                         pr_debug("Read_old block %d for r-m-w\n",
4243                                                  i);
4244                                         set_bit(R5_LOCKED, &dev->flags);
4245                                         set_bit(R5_Wantread, &dev->flags);
4246                                         s->locked++;
4247                                 } else
4248                                         set_bit(STRIPE_DELAYED, &sh->state);
4249                         }
4250                 }
4251         }
4252         if ((rcw < rmw || (rcw == rmw && conf->rmw_level != PARITY_PREFER_RMW)) && rcw > 0) {
4253                 /* want reconstruct write, but need to get some data */
4254                 int qread =0;
4255                 rcw = 0;
4256                 for (i = disks; i--; ) {
4257                         struct r5dev *dev = &sh->dev[i];
4258                         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
4259                             i != sh->pd_idx && i != sh->qd_idx &&
4260                             !test_bit(R5_LOCKED, &dev->flags) &&
4261                             !(test_bit(R5_UPTODATE, &dev->flags) ||
4262                               test_bit(R5_Wantcompute, &dev->flags))) {
4263                                 rcw++;
4264                                 if (test_bit(R5_Insync, &dev->flags) &&
4265                                     test_bit(STRIPE_PREREAD_ACTIVE,
4266                                              &sh->state)) {
4267                                         pr_debug("Read_old block "
4268                                                 "%d for Reconstruct\n", i);
4269                                         set_bit(R5_LOCKED, &dev->flags);
4270                                         set_bit(R5_Wantread, &dev->flags);
4271                                         s->locked++;
4272                                         qread++;
4273                                 } else
4274                                         set_bit(STRIPE_DELAYED, &sh->state);
4275                         }
4276                 }
4277                 if (rcw && !mddev_is_dm(conf->mddev))
4278                         blk_add_trace_msg(conf->mddev->gendisk->queue,
4279                                 "raid5 rcw %llu %d %d %d",
4280                                 (unsigned long long)sh->sector, rcw, qread,
4281                                 test_bit(STRIPE_DELAYED, &sh->state));
4282         }
4283
4284         if (rcw > disks && rmw > disks &&
4285             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4286                 set_bit(STRIPE_DELAYED, &sh->state);
4287
4288         /* now if nothing is locked, and if we have enough data,
4289          * we can start a write request
4290          */
4291         /* since handle_stripe can be called at any time we need to handle the
4292          * case where a compute block operation has been submitted and then a
4293          * subsequent call wants to start a write request.  raid_run_ops only
4294          * handles the case where compute block and reconstruct are requested
4295          * simultaneously.  If this is not the case then new writes need to be
4296          * held off until the compute completes.
4297          */
4298         if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
4299             (s->locked == 0 && (rcw == 0 || rmw == 0) &&
4300              !test_bit(STRIPE_BIT_DELAY, &sh->state)))
4301                 schedule_reconstruction(sh, s, rcw == 0, 0);
4302         return 0;
4303 }
4304
4305 static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
4306                                 struct stripe_head_state *s, int disks)
4307 {
4308         struct r5dev *dev = NULL;
4309
4310         BUG_ON(sh->batch_head);
4311         set_bit(STRIPE_HANDLE, &sh->state);
4312
4313         switch (sh->check_state) {
4314         case check_state_idle:
4315                 /* start a new check operation if there are no failures */
4316                 if (s->failed == 0) {
4317                         BUG_ON(s->uptodate != disks);
4318                         sh->check_state = check_state_run;
4319                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4320                         clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4321                         s->uptodate--;
4322                         break;
4323                 }
4324                 dev = &sh->dev[s->failed_num[0]];
4325                 fallthrough;
4326         case check_state_compute_result:
4327                 sh->check_state = check_state_idle;
4328                 if (!dev)
4329                         dev = &sh->dev[sh->pd_idx];
4330
4331                 /* check that a write has not made the stripe insync */
4332                 if (test_bit(STRIPE_INSYNC, &sh->state))
4333                         break;
4334
4335                 /* either failed parity check, or recovery is happening */
4336                 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
4337                 BUG_ON(s->uptodate != disks);
4338
4339                 set_bit(R5_LOCKED, &dev->flags);
4340                 s->locked++;
4341                 set_bit(R5_Wantwrite, &dev->flags);
4342
4343                 clear_bit(STRIPE_DEGRADED, &sh->state);
4344                 set_bit(STRIPE_INSYNC, &sh->state);
4345                 break;
4346         case check_state_run:
4347                 break; /* we will be called again upon completion */
4348         case check_state_check_result:
4349                 sh->check_state = check_state_idle;
4350
4351                 /* if a failure occurred during the check operation, leave
4352                  * STRIPE_INSYNC not set and let the stripe be handled again
4353                  */
4354                 if (s->failed)
4355                         break;
4356
4357                 /* handle a successful check operation, if parity is correct
4358                  * we are done.  Otherwise update the mismatch count and repair
4359                  * parity if !MD_RECOVERY_CHECK
4360                  */
4361                 if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
4362                         /* parity is correct (on disc,
4363                          * not in buffer any more)
4364                          */
4365                         set_bit(STRIPE_INSYNC, &sh->state);
4366                 else {
4367                         atomic64_add(RAID5_STRIPE_SECTORS(conf), &conf->mddev->resync_mismatches);
4368                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4369                                 /* don't try to repair!! */
4370                                 set_bit(STRIPE_INSYNC, &sh->state);
4371                                 pr_warn_ratelimited("%s: mismatch sector in range "
4372                                                     "%llu-%llu\n", mdname(conf->mddev),
4373                                                     (unsigned long long) sh->sector,
4374                                                     (unsigned long long) sh->sector +
4375                                                     RAID5_STRIPE_SECTORS(conf));
4376                         } else {
4377                                 sh->check_state = check_state_compute_run;
4378                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4379                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4380                                 set_bit(R5_Wantcompute,
4381                                         &sh->dev[sh->pd_idx].flags);
4382                                 sh->ops.target = sh->pd_idx;
4383                                 sh->ops.target2 = -1;
4384                                 s->uptodate++;
4385                         }
4386                 }
4387                 break;
4388         case check_state_compute_run:
4389                 break;
4390         default:
4391                 pr_err("%s: unknown check_state: %d sector: %llu\n",
4392                        __func__, sh->check_state,
4393                        (unsigned long long) sh->sector);
4394                 BUG();
4395         }
4396 }
4397
4398 static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
4399                                   struct stripe_head_state *s,
4400                                   int disks)
4401 {
4402         int pd_idx = sh->pd_idx;
4403         int qd_idx = sh->qd_idx;
4404         struct r5dev *dev;
4405
4406         BUG_ON(sh->batch_head);
4407         set_bit(STRIPE_HANDLE, &sh->state);
4408
4409         BUG_ON(s->failed > 2);
4410
4411         /* Want to check and possibly repair P and Q.
4412          * However there could be one 'failed' device, in which
4413          * case we can only check one of them, possibly using the
4414          * other to generate missing data
4415          */
4416
4417         switch (sh->check_state) {
4418         case check_state_idle:
4419                 /* start a new check operation if there are < 2 failures */
4420                 if (s->failed == s->q_failed) {
4421                         /* The only possible failed device holds Q, so it
4422                          * makes sense to check P (If anything else were failed,
4423                          * we would have used P to recreate it).
4424                          */
4425                         sh->check_state = check_state_run;
4426                 }
4427                 if (!s->q_failed && s->failed < 2) {
4428                         /* Q is not failed, and we didn't use it to generate
4429                          * anything, so it makes sense to check it
4430                          */
4431                         if (sh->check_state == check_state_run)
4432                                 sh->check_state = check_state_run_pq;
4433                         else
4434                                 sh->check_state = check_state_run_q;
4435                 }
4436
4437                 /* discard potentially stale zero_sum_result */
4438                 sh->ops.zero_sum_result = 0;
4439
4440                 if (sh->check_state == check_state_run) {
4441                         /* async_xor_zero_sum destroys the contents of P */
4442                         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
4443                         s->uptodate--;
4444                 }
4445                 if (sh->check_state >= check_state_run &&
4446                     sh->check_state <= check_state_run_pq) {
4447                         /* async_syndrome_zero_sum preserves P and Q, so
4448                          * no need to mark them !uptodate here
4449                          */
4450                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4451                         break;
4452                 }
4453
4454                 /* we have 2-disk failure */
4455                 BUG_ON(s->failed != 2);
4456                 fallthrough;
4457         case check_state_compute_result:
4458                 sh->check_state = check_state_idle;
4459
4460                 /* check that a write has not made the stripe insync */
4461                 if (test_bit(STRIPE_INSYNC, &sh->state))
4462                         break;
4463
4464                 /* now write out any block on a failed drive,
4465                  * or P or Q if they were recomputed
4466                  */
4467                 dev = NULL;
4468                 if (s->failed == 2) {
4469                         dev = &sh->dev[s->failed_num[1]];
4470                         s->locked++;
4471                         set_bit(R5_LOCKED, &dev->flags);
4472                         set_bit(R5_Wantwrite, &dev->flags);
4473                 }
4474                 if (s->failed >= 1) {
4475                         dev = &sh->dev[s->failed_num[0]];
4476                         s->locked++;
4477                         set_bit(R5_LOCKED, &dev->flags);
4478                         set_bit(R5_Wantwrite, &dev->flags);
4479                 }
4480                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4481                         dev = &sh->dev[pd_idx];
4482                         s->locked++;
4483                         set_bit(R5_LOCKED, &dev->flags);
4484                         set_bit(R5_Wantwrite, &dev->flags);
4485                 }
4486                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4487                         dev = &sh->dev[qd_idx];
4488                         s->locked++;
4489                         set_bit(R5_LOCKED, &dev->flags);
4490                         set_bit(R5_Wantwrite, &dev->flags);
4491                 }
4492                 if (WARN_ONCE(dev && !test_bit(R5_UPTODATE, &dev->flags),
4493                               "%s: disk%td not up to date\n",
4494                               mdname(conf->mddev),
4495                               dev - (struct r5dev *) &sh->dev)) {
4496                         clear_bit(R5_LOCKED, &dev->flags);
4497                         clear_bit(R5_Wantwrite, &dev->flags);
4498                         s->locked--;
4499                 }
4500                 clear_bit(STRIPE_DEGRADED, &sh->state);
4501
4502                 set_bit(STRIPE_INSYNC, &sh->state);
4503                 break;
4504         case check_state_run:
4505         case check_state_run_q:
4506         case check_state_run_pq:
4507                 break; /* we will be called again upon completion */
4508         case check_state_check_result:
4509                 sh->check_state = check_state_idle;
4510
4511                 /* handle a successful check operation, if parity is correct
4512                  * we are done.  Otherwise update the mismatch count and repair
4513                  * parity if !MD_RECOVERY_CHECK
4514                  */
4515                 if (sh->ops.zero_sum_result == 0) {
4516                         /* both parities are correct */
4517                         if (!s->failed)
4518                                 set_bit(STRIPE_INSYNC, &sh->state);
4519                         else {
4520                                 /* in contrast to the raid5 case we can validate
4521                                  * parity, but still have a failure to write
4522                                  * back
4523                                  */
4524                                 sh->check_state = check_state_compute_result;
4525                                 /* Returning at this point means that we may go
4526                                  * off and bring p and/or q uptodate again so
4527                                  * we make sure to check zero_sum_result again
4528                                  * to verify if p or q need writeback
4529                                  */
4530                         }
4531                 } else {
4532                         atomic64_add(RAID5_STRIPE_SECTORS(conf), &conf->mddev->resync_mismatches);
4533                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4534                                 /* don't try to repair!! */
4535                                 set_bit(STRIPE_INSYNC, &sh->state);
4536                                 pr_warn_ratelimited("%s: mismatch sector in range "
4537                                                     "%llu-%llu\n", mdname(conf->mddev),
4538                                                     (unsigned long long) sh->sector,
4539                                                     (unsigned long long) sh->sector +
4540                                                     RAID5_STRIPE_SECTORS(conf));
4541                         } else {
4542                                 int *target = &sh->ops.target;
4543
4544                                 sh->ops.target = -1;
4545                                 sh->ops.target2 = -1;
4546                                 sh->check_state = check_state_compute_run;
4547                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4548                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4549                                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4550                                         set_bit(R5_Wantcompute,
4551                                                 &sh->dev[pd_idx].flags);
4552                                         *target = pd_idx;
4553                                         target = &sh->ops.target2;
4554                                         s->uptodate++;
4555                                 }
4556                                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4557                                         set_bit(R5_Wantcompute,
4558                                                 &sh->dev[qd_idx].flags);
4559                                         *target = qd_idx;
4560                                         s->uptodate++;
4561                                 }
4562                         }
4563                 }
4564                 break;
4565         case check_state_compute_run:
4566                 break;
4567         default:
4568                 pr_warn("%s: unknown check_state: %d sector: %llu\n",
4569                         __func__, sh->check_state,
4570                         (unsigned long long) sh->sector);
4571                 BUG();
4572         }
4573 }
4574
4575 static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
4576 {
4577         int i;
4578
4579         /* We have read all the blocks in this stripe and now we need to
4580          * copy some of them into a target stripe for expand.
4581          */
4582         struct dma_async_tx_descriptor *tx = NULL;
4583         BUG_ON(sh->batch_head);
4584         clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
4585         for (i = 0; i < sh->disks; i++)
4586                 if (i != sh->pd_idx && i != sh->qd_idx) {
4587                         int dd_idx, j;
4588                         struct stripe_head *sh2;
4589                         struct async_submit_ctl submit;
4590
4591                         sector_t bn = raid5_compute_blocknr(sh, i, 1);
4592                         sector_t s = raid5_compute_sector(conf, bn, 0,
4593                                                           &dd_idx, NULL);
4594                         sh2 = raid5_get_active_stripe(conf, NULL, s,
4595                                 R5_GAS_NOBLOCK | R5_GAS_NOQUIESCE);
4596                         if (sh2 == NULL)
4597                                 /* so far only the early blocks of this stripe
4598                                  * have been requested.  When later blocks
4599                                  * get requested, we will try again
4600                                  */
4601                                 continue;
4602                         if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
4603                            test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
4604                                 /* must have already done this block */
4605                                 raid5_release_stripe(sh2);
4606                                 continue;
4607                         }
4608
4609                         /* place all the copies on one channel */
4610                         init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
4611                         tx = async_memcpy(sh2->dev[dd_idx].page,
4612                                           sh->dev[i].page, sh2->dev[dd_idx].offset,
4613                                           sh->dev[i].offset, RAID5_STRIPE_SIZE(conf),
4614                                           &submit);
4615
4616                         set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
4617                         set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
4618                         for (j = 0; j < conf->raid_disks; j++)
4619                                 if (j != sh2->pd_idx &&
4620                                     j != sh2->qd_idx &&
4621                                     !test_bit(R5_Expanded, &sh2->dev[j].flags))
4622                                         break;
4623                         if (j == conf->raid_disks) {
4624                                 set_bit(STRIPE_EXPAND_READY, &sh2->state);
4625                                 set_bit(STRIPE_HANDLE, &sh2->state);
4626                         }
4627                         raid5_release_stripe(sh2);
4628
4629                 }
4630         /* done submitting copies, wait for them to complete */
4631         async_tx_quiesce(&tx);
4632 }
4633
4634 /*
4635  * handle_stripe - do things to a stripe.
4636  *
4637  * We lock the stripe by setting STRIPE_ACTIVE and then examine the
4638  * state of various bits to see what needs to be done.
4639  * Possible results:
4640  *    return some read requests which now have data
4641  *    return some write requests which are safely on storage
4642  *    schedule a read on some buffers
4643  *    schedule a write of some buffers
4644  *    return confirmation of parity correctness
4645  *
4646  */
4647
4648 static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
4649 {
4650         struct r5conf *conf = sh->raid_conf;
4651         int disks = sh->disks;
4652         struct r5dev *dev;
4653         int i;
4654         int do_recovery = 0;
4655
4656         memset(s, 0, sizeof(*s));
4657
4658         s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state) && !sh->batch_head;
4659         s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state) && !sh->batch_head;
4660         s->failed_num[0] = -1;
4661         s->failed_num[1] = -1;
4662         s->log_failed = r5l_log_disk_error(conf);
4663
4664         /* Now to look around and see what can be done */
4665         for (i=disks; i--; ) {
4666                 struct md_rdev *rdev;
4667                 int is_bad = 0;
4668
4669                 dev = &sh->dev[i];
4670
4671                 pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
4672                          i, dev->flags,
4673                          dev->toread, dev->towrite, dev->written);
4674                 /* maybe we can reply to a read
4675                  *
4676                  * new wantfill requests are only permitted while
4677                  * ops_complete_biofill is guaranteed to be inactive
4678                  */
4679                 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
4680                     !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
4681                         set_bit(R5_Wantfill, &dev->flags);
4682
4683                 /* now count some things */
4684                 if (test_bit(R5_LOCKED, &dev->flags))
4685                         s->locked++;
4686                 if (test_bit(R5_UPTODATE, &dev->flags))
4687                         s->uptodate++;
4688                 if (test_bit(R5_Wantcompute, &dev->flags)) {
4689                         s->compute++;
4690                         BUG_ON(s->compute > 2);
4691                 }
4692
4693                 if (test_bit(R5_Wantfill, &dev->flags))
4694                         s->to_fill++;
4695                 else if (dev->toread)
4696                         s->to_read++;
4697                 if (dev->towrite) {
4698                         s->to_write++;
4699                         if (!test_bit(R5_OVERWRITE, &dev->flags))
4700                                 s->non_overwrite++;
4701                 }
4702                 if (dev->written)
4703                         s->written++;
4704                 /* Prefer to use the replacement for reads, but only
4705                  * if it is recovered enough and has no bad blocks.
4706                  */
4707                 rdev = conf->disks[i].replacement;
4708                 if (rdev && !test_bit(Faulty, &rdev->flags) &&
4709                     rdev->recovery_offset >= sh->sector + RAID5_STRIPE_SECTORS(conf) &&
4710                     !rdev_has_badblock(rdev, sh->sector,
4711                                        RAID5_STRIPE_SECTORS(conf)))
4712                         set_bit(R5_ReadRepl, &dev->flags);
4713                 else {
4714                         if (rdev && !test_bit(Faulty, &rdev->flags))
4715                                 set_bit(R5_NeedReplace, &dev->flags);
4716                         else
4717                                 clear_bit(R5_NeedReplace, &dev->flags);
4718                         rdev = conf->disks[i].rdev;
4719                         clear_bit(R5_ReadRepl, &dev->flags);
4720                 }
4721                 if (rdev && test_bit(Faulty, &rdev->flags))
4722                         rdev = NULL;
4723                 if (rdev) {
4724                         is_bad = rdev_has_badblock(rdev, sh->sector,
4725                                                    RAID5_STRIPE_SECTORS(conf));
4726                         if (s->blocked_rdev == NULL
4727                             && (test_bit(Blocked, &rdev->flags)
4728                                 || is_bad < 0)) {
4729                                 if (is_bad < 0)
4730                                         set_bit(BlockedBadBlocks,
4731                                                 &rdev->flags);
4732                                 s->blocked_rdev = rdev;
4733                                 atomic_inc(&rdev->nr_pending);
4734                         }
4735                 }
4736                 clear_bit(R5_Insync, &dev->flags);
4737                 if (!rdev)
4738                         /* Not in-sync */;
4739                 else if (is_bad) {
4740                         /* also not in-sync */
4741                         if (!test_bit(WriteErrorSeen, &rdev->flags) &&
4742                             test_bit(R5_UPTODATE, &dev->flags)) {
4743                                 /* treat as in-sync, but with a read error
4744                                  * which we can now try to correct
4745                                  */
4746                                 set_bit(R5_Insync, &dev->flags);
4747                                 set_bit(R5_ReadError, &dev->flags);
4748                         }
4749                 } else if (test_bit(In_sync, &rdev->flags))
4750                         set_bit(R5_Insync, &dev->flags);
4751                 else if (sh->sector + RAID5_STRIPE_SECTORS(conf) <= rdev->recovery_offset)
4752                         /* in sync if before recovery_offset */
4753                         set_bit(R5_Insync, &dev->flags);
4754                 else if (test_bit(R5_UPTODATE, &dev->flags) &&
4755                          test_bit(R5_Expanded, &dev->flags))
4756                         /* If we've reshaped into here, we assume it is Insync.
4757                          * We will shortly update recovery_offset to make
4758                          * it official.
4759                          */
4760                         set_bit(R5_Insync, &dev->flags);
4761
4762                 if (test_bit(R5_WriteError, &dev->flags)) {
4763                         /* This flag does not apply to '.replacement'
4764                          * only to .rdev, so make sure to check that*/
4765                         struct md_rdev *rdev2 = conf->disks[i].rdev;
4766
4767                         if (rdev2 == rdev)
4768                                 clear_bit(R5_Insync, &dev->flags);
4769                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4770                                 s->handle_bad_blocks = 1;
4771                                 atomic_inc(&rdev2->nr_pending);
4772                         } else
4773                                 clear_bit(R5_WriteError, &dev->flags);
4774                 }
4775                 if (test_bit(R5_MadeGood, &dev->flags)) {
4776                         /* This flag does not apply to '.replacement'
4777                          * only to .rdev, so make sure to check that*/
4778                         struct md_rdev *rdev2 = conf->disks[i].rdev;
4779
4780                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4781                                 s->handle_bad_blocks = 1;
4782                                 atomic_inc(&rdev2->nr_pending);
4783                         } else
4784                                 clear_bit(R5_MadeGood, &dev->flags);
4785                 }
4786                 if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
4787                         struct md_rdev *rdev2 = conf->disks[i].replacement;
4788
4789                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4790                                 s->handle_bad_blocks = 1;
4791                                 atomic_inc(&rdev2->nr_pending);
4792                         } else
4793                                 clear_bit(R5_MadeGoodRepl, &dev->flags);
4794                 }
4795                 if (!test_bit(R5_Insync, &dev->flags)) {
4796                         /* The ReadError flag will just be confusing now */
4797                         clear_bit(R5_ReadError, &dev->flags);
4798                         clear_bit(R5_ReWrite, &dev->flags);
4799                 }
4800                 if (test_bit(R5_ReadError, &dev->flags))
4801                         clear_bit(R5_Insync, &dev->flags);
4802                 if (!test_bit(R5_Insync, &dev->flags)) {
4803                         if (s->failed < 2)
4804                                 s->failed_num[s->failed] = i;
4805                         s->failed++;
4806                         if (rdev && !test_bit(Faulty, &rdev->flags))
4807                                 do_recovery = 1;
4808                         else if (!rdev) {
4809                                 rdev = conf->disks[i].replacement;
4810                                 if (rdev && !test_bit(Faulty, &rdev->flags))
4811                                         do_recovery = 1;
4812                         }
4813                 }
4814
4815                 if (test_bit(R5_InJournal, &dev->flags))
4816                         s->injournal++;
4817                 if (test_bit(R5_InJournal, &dev->flags) && dev->written)
4818                         s->just_cached++;
4819         }
4820         if (test_bit(STRIPE_SYNCING, &sh->state)) {
4821                 /* If there is a failed device being replaced,
4822                  *     we must be recovering.
4823                  * else if we are after recovery_cp, we must be syncing
4824                  * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
4825                  * else we can only be replacing
4826                  * sync and recovery both need to read all devices, and so
4827                  * use the same flag.
4828                  */
4829                 if (do_recovery ||
4830                     sh->sector >= conf->mddev->recovery_cp ||
4831                     test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
4832                         s->syncing = 1;
4833                 else
4834                         s->replacing = 1;
4835         }
4836 }
4837
4838 /*
4839  * Return '1' if this is a member of batch, or '0' if it is a lone stripe or
4840  * a head which can now be handled.
4841  */
4842 static int clear_batch_ready(struct stripe_head *sh)
4843 {
4844         struct stripe_head *tmp;
4845         if (!test_and_clear_bit(STRIPE_BATCH_READY, &sh->state))
4846                 return (sh->batch_head && sh->batch_head != sh);
4847         spin_lock(&sh->stripe_lock);
4848         if (!sh->batch_head) {
4849                 spin_unlock(&sh->stripe_lock);
4850                 return 0;
4851         }
4852
4853         /*
4854          * this stripe could be added to a batch list before we check
4855          * BATCH_READY, skips it
4856          */
4857         if (sh->batch_head != sh) {
4858                 spin_unlock(&sh->stripe_lock);
4859                 return 1;
4860         }
4861         spin_lock(&sh->batch_lock);
4862         list_for_each_entry(tmp, &sh->batch_list, batch_list)
4863                 clear_bit(STRIPE_BATCH_READY, &tmp->state);
4864         spin_unlock(&sh->batch_lock);
4865         spin_unlock(&sh->stripe_lock);
4866
4867         /*
4868          * BATCH_READY is cleared, no new stripes can be added.
4869          * batch_list can be accessed without lock
4870          */
4871         return 0;
4872 }
4873
4874 static void break_stripe_batch_list(struct stripe_head *head_sh,
4875                                     unsigned long handle_flags)
4876 {
4877         struct stripe_head *sh, *next;
4878         int i;
4879         int do_wakeup = 0;
4880
4881         list_for_each_entry_safe(sh, next, &head_sh->batch_list, batch_list) {
4882
4883                 list_del_init(&sh->batch_list);
4884
4885                 WARN_ONCE(sh->state & ((1 << STRIPE_ACTIVE) |
4886                                           (1 << STRIPE_SYNCING) |
4887                                           (1 << STRIPE_REPLACED) |
4888                                           (1 << STRIPE_DELAYED) |
4889                                           (1 << STRIPE_BIT_DELAY) |
4890                                           (1 << STRIPE_FULL_WRITE) |
4891                                           (1 << STRIPE_BIOFILL_RUN) |
4892                                           (1 << STRIPE_COMPUTE_RUN)  |
4893                                           (1 << STRIPE_DISCARD) |
4894                                           (1 << STRIPE_BATCH_READY) |
4895                                           (1 << STRIPE_BATCH_ERR) |
4896                                           (1 << STRIPE_BITMAP_PENDING)),
4897                         "stripe state: %lx\n", sh->state);
4898                 WARN_ONCE(head_sh->state & ((1 << STRIPE_DISCARD) |
4899                                               (1 << STRIPE_REPLACED)),
4900                         "head stripe state: %lx\n", head_sh->state);
4901
4902                 set_mask_bits(&sh->state, ~(STRIPE_EXPAND_SYNC_FLAGS |
4903                                             (1 << STRIPE_PREREAD_ACTIVE) |
4904                                             (1 << STRIPE_DEGRADED) |
4905                                             (1 << STRIPE_ON_UNPLUG_LIST)),
4906                               head_sh->state & (1 << STRIPE_INSYNC));
4907
4908                 sh->check_state = head_sh->check_state;
4909                 sh->reconstruct_state = head_sh->reconstruct_state;
4910                 spin_lock_irq(&sh->stripe_lock);
4911                 sh->batch_head = NULL;
4912                 spin_unlock_irq(&sh->stripe_lock);
4913                 for (i = 0; i < sh->disks; i++) {
4914                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
4915                                 do_wakeup = 1;
4916                         sh->dev[i].flags = head_sh->dev[i].flags &
4917                                 (~((1 << R5_WriteError) | (1 << R5_Overlap)));
4918                 }
4919                 if (handle_flags == 0 ||
4920                     sh->state & handle_flags)
4921                         set_bit(STRIPE_HANDLE, &sh->state);
4922                 raid5_release_stripe(sh);
4923         }
4924         spin_lock_irq(&head_sh->stripe_lock);
4925         head_sh->batch_head = NULL;
4926         spin_unlock_irq(&head_sh->stripe_lock);
4927         for (i = 0; i < head_sh->disks; i++)
4928                 if (test_and_clear_bit(R5_Overlap, &head_sh->dev[i].flags))
4929                         do_wakeup = 1;
4930         if (head_sh->state & handle_flags)
4931                 set_bit(STRIPE_HANDLE, &head_sh->state);
4932
4933         if (do_wakeup)
4934                 wake_up(&head_sh->raid_conf->wait_for_overlap);
4935 }
4936
4937 static void handle_stripe(struct stripe_head *sh)
4938 {
4939         struct stripe_head_state s;
4940         struct r5conf *conf = sh->raid_conf;
4941         int i;
4942         int prexor;
4943         int disks = sh->disks;
4944         struct r5dev *pdev, *qdev;
4945
4946         clear_bit(STRIPE_HANDLE, &sh->state);
4947
4948         /*
4949          * handle_stripe should not continue handle the batched stripe, only
4950          * the head of batch list or lone stripe can continue. Otherwise we
4951          * could see break_stripe_batch_list warns about the STRIPE_ACTIVE
4952          * is set for the batched stripe.
4953          */
4954         if (clear_batch_ready(sh))
4955                 return;
4956
4957         if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
4958                 /* already being handled, ensure it gets handled
4959                  * again when current action finishes */
4960                 set_bit(STRIPE_HANDLE, &sh->state);
4961                 return;
4962         }
4963
4964         if (test_and_clear_bit(STRIPE_BATCH_ERR, &sh->state))
4965                 break_stripe_batch_list(sh, 0);
4966
4967         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) && !sh->batch_head) {
4968                 spin_lock(&sh->stripe_lock);
4969                 /*
4970                  * Cannot process 'sync' concurrently with 'discard'.
4971                  * Flush data in r5cache before 'sync'.
4972                  */
4973                 if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) &&
4974                     !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) &&
4975                     !test_bit(STRIPE_DISCARD, &sh->state) &&
4976                     test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
4977                         set_bit(STRIPE_SYNCING, &sh->state);
4978                         clear_bit(STRIPE_INSYNC, &sh->state);
4979                         clear_bit(STRIPE_REPLACED, &sh->state);
4980                 }
4981                 spin_unlock(&sh->stripe_lock);
4982         }
4983         clear_bit(STRIPE_DELAYED, &sh->state);
4984
4985         pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
4986                 "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
4987                (unsigned long long)sh->sector, sh->state,
4988                atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
4989                sh->check_state, sh->reconstruct_state);
4990
4991         analyse_stripe(sh, &s);
4992
4993         if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
4994                 goto finish;
4995
4996         if (s.handle_bad_blocks ||
4997             test_bit(MD_SB_CHANGE_PENDING, &conf->mddev->sb_flags)) {
4998                 set_bit(STRIPE_HANDLE, &sh->state);
4999                 goto finish;
5000         }
5001
5002         if (unlikely(s.blocked_rdev)) {
5003                 if (s.syncing || s.expanding || s.expanded ||
5004                     s.replacing || s.to_write || s.written) {
5005                         set_bit(STRIPE_HANDLE, &sh->state);
5006                         goto finish;
5007                 }
5008                 /* There is nothing for the blocked_rdev to block */
5009                 rdev_dec_pending(s.blocked_rdev, conf->mddev);
5010                 s.blocked_rdev = NULL;
5011         }
5012
5013         if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
5014                 set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
5015                 set_bit(STRIPE_BIOFILL_RUN, &sh->state);
5016         }
5017
5018         pr_debug("locked=%d uptodate=%d to_read=%d"
5019                " to_write=%d failed=%d failed_num=%d,%d\n",
5020                s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
5021                s.failed_num[0], s.failed_num[1]);
5022         /*
5023          * check if the array has lost more than max_degraded devices and,
5024          * if so, some requests might need to be failed.
5025          *
5026          * When journal device failed (log_failed), we will only process
5027          * the stripe if there is data need write to raid disks
5028          */
5029         if (s.failed > conf->max_degraded ||
5030             (s.log_failed && s.injournal == 0)) {
5031                 sh->check_state = 0;
5032                 sh->reconstruct_state = 0;
5033                 break_stripe_batch_list(sh, 0);
5034                 if (s.to_read+s.to_write+s.written)
5035                         handle_failed_stripe(conf, sh, &s, disks);
5036                 if (s.syncing + s.replacing)
5037                         handle_failed_sync(conf, sh, &s);
5038         }
5039
5040         /* Now we check to see if any write operations have recently
5041          * completed
5042          */
5043         prexor = 0;
5044         if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
5045                 prexor = 1;
5046         if (sh->reconstruct_state == reconstruct_state_drain_result ||
5047             sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
5048                 sh->reconstruct_state = reconstruct_state_idle;
5049
5050                 /* All the 'written' buffers and the parity block are ready to
5051                  * be written back to disk
5052                  */
5053                 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
5054                        !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
5055                 BUG_ON(sh->qd_idx >= 0 &&
5056                        !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
5057                        !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
5058                 for (i = disks; i--; ) {
5059                         struct r5dev *dev = &sh->dev[i];
5060                         if (test_bit(R5_LOCKED, &dev->flags) &&
5061                                 (i == sh->pd_idx || i == sh->qd_idx ||
5062                                  dev->written || test_bit(R5_InJournal,
5063                                                           &dev->flags))) {
5064                                 pr_debug("Writing block %d\n", i);
5065                                 set_bit(R5_Wantwrite, &dev->flags);
5066                                 if (prexor)
5067                                         continue;
5068                                 if (s.failed > 1)
5069                                         continue;
5070                                 if (!test_bit(R5_Insync, &dev->flags) ||
5071                                     ((i == sh->pd_idx || i == sh->qd_idx)  &&
5072                                      s.failed == 0))
5073                                         set_bit(STRIPE_INSYNC, &sh->state);
5074                         }
5075                 }
5076                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5077                         s.dec_preread_active = 1;
5078         }
5079
5080         /*
5081          * might be able to return some write requests if the parity blocks
5082          * are safe, or on a failed drive
5083          */
5084         pdev = &sh->dev[sh->pd_idx];
5085         s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
5086                 || (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
5087         qdev = &sh->dev[sh->qd_idx];
5088         s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
5089                 || (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
5090                 || conf->level < 6;
5091
5092         if (s.written &&
5093             (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
5094                              && !test_bit(R5_LOCKED, &pdev->flags)
5095                              && (test_bit(R5_UPTODATE, &pdev->flags) ||
5096                                  test_bit(R5_Discard, &pdev->flags))))) &&
5097             (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
5098                              && !test_bit(R5_LOCKED, &qdev->flags)
5099                              && (test_bit(R5_UPTODATE, &qdev->flags) ||
5100                                  test_bit(R5_Discard, &qdev->flags))))))
5101                 handle_stripe_clean_event(conf, sh, disks);
5102
5103         if (s.just_cached)
5104                 r5c_handle_cached_data_endio(conf, sh, disks);
5105         log_stripe_write_finished(sh);
5106
5107         /* Now we might consider reading some blocks, either to check/generate
5108          * parity, or to satisfy requests
5109          * or to load a block that is being partially written.
5110          */
5111         if (s.to_read || s.non_overwrite
5112             || (s.to_write && s.failed)
5113             || (s.syncing && (s.uptodate + s.compute < disks))
5114             || s.replacing
5115             || s.expanding)
5116                 handle_stripe_fill(sh, &s, disks);
5117
5118         /*
5119          * When the stripe finishes full journal write cycle (write to journal
5120          * and raid disk), this is the clean up procedure so it is ready for
5121          * next operation.
5122          */
5123         r5c_finish_stripe_write_out(conf, sh, &s);
5124
5125         /*
5126          * Now to consider new write requests, cache write back and what else,
5127          * if anything should be read.  We do not handle new writes when:
5128          * 1/ A 'write' operation (copy+xor) is already in flight.
5129          * 2/ A 'check' operation is in flight, as it may clobber the parity
5130          *    block.
5131          * 3/ A r5c cache log write is in flight.
5132          */
5133
5134         if (!sh->reconstruct_state && !sh->check_state && !sh->log_io) {
5135                 if (!r5c_is_writeback(conf->log)) {
5136                         if (s.to_write)
5137                                 handle_stripe_dirtying(conf, sh, &s, disks);
5138                 } else { /* write back cache */
5139                         int ret = 0;
5140
5141                         /* First, try handle writes in caching phase */
5142                         if (s.to_write)
5143                                 ret = r5c_try_caching_write(conf, sh, &s,
5144                                                             disks);
5145                         /*
5146                          * If caching phase failed: ret == -EAGAIN
5147                          *    OR
5148                          * stripe under reclaim: !caching && injournal
5149                          *
5150                          * fall back to handle_stripe_dirtying()
5151                          */
5152                         if (ret == -EAGAIN ||
5153                             /* stripe under reclaim: !caching && injournal */
5154                             (!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
5155                              s.injournal > 0)) {
5156                                 ret = handle_stripe_dirtying(conf, sh, &s,
5157                                                              disks);
5158                                 if (ret == -EAGAIN)
5159                                         goto finish;
5160                         }
5161                 }
5162         }
5163
5164         /* maybe we need to check and possibly fix the parity for this stripe
5165          * Any reads will already have been scheduled, so we just see if enough
5166          * data is available.  The parity check is held off while parity
5167          * dependent operations are in flight.
5168          */
5169         if (sh->check_state ||
5170             (s.syncing && s.locked == 0 &&
5171              !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
5172              !test_bit(STRIPE_INSYNC, &sh->state))) {
5173                 if (conf->level == 6)
5174                         handle_parity_checks6(conf, sh, &s, disks);
5175                 else
5176                         handle_parity_checks5(conf, sh, &s, disks);
5177         }
5178
5179         if ((s.replacing || s.syncing) && s.locked == 0
5180             && !test_bit(STRIPE_COMPUTE_RUN, &sh->state)
5181             && !test_bit(STRIPE_REPLACED, &sh->state)) {
5182                 /* Write out to replacement devices where possible */
5183                 for (i = 0; i < conf->raid_disks; i++)
5184                         if (test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
5185                                 WARN_ON(!test_bit(R5_UPTODATE, &sh->dev[i].flags));
5186                                 set_bit(R5_WantReplace, &sh->dev[i].flags);
5187                                 set_bit(R5_LOCKED, &sh->dev[i].flags);
5188                                 s.locked++;
5189                         }
5190                 if (s.replacing)
5191                         set_bit(STRIPE_INSYNC, &sh->state);
5192                 set_bit(STRIPE_REPLACED, &sh->state);
5193         }
5194         if ((s.syncing || s.replacing) && s.locked == 0 &&
5195             !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
5196             test_bit(STRIPE_INSYNC, &sh->state)) {
5197                 md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), 1);
5198                 clear_bit(STRIPE_SYNCING, &sh->state);
5199                 if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
5200                         wake_up(&conf->wait_for_overlap);
5201         }
5202
5203         /* If the failed drives are just a ReadError, then we might need
5204          * to progress the repair/check process
5205          */
5206         if (s.failed <= conf->max_degraded && !conf->mddev->ro)
5207                 for (i = 0; i < s.failed; i++) {
5208                         struct r5dev *dev = &sh->dev[s.failed_num[i]];
5209                         if (test_bit(R5_ReadError, &dev->flags)
5210                             && !test_bit(R5_LOCKED, &dev->flags)
5211                             && test_bit(R5_UPTODATE, &dev->flags)
5212                                 ) {
5213                                 if (!test_bit(R5_ReWrite, &dev->flags)) {
5214                                         set_bit(R5_Wantwrite, &dev->flags);
5215                                         set_bit(R5_ReWrite, &dev->flags);
5216                                 } else
5217                                         /* let's read it back */
5218                                         set_bit(R5_Wantread, &dev->flags);
5219                                 set_bit(R5_LOCKED, &dev->flags);
5220                                 s.locked++;
5221                         }
5222                 }
5223
5224         /* Finish reconstruct operations initiated by the expansion process */
5225         if (sh->reconstruct_state == reconstruct_state_result) {
5226                 struct stripe_head *sh_src
5227                         = raid5_get_active_stripe(conf, NULL, sh->sector,
5228                                         R5_GAS_PREVIOUS | R5_GAS_NOBLOCK |
5229                                         R5_GAS_NOQUIESCE);
5230                 if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
5231                         /* sh cannot be written until sh_src has been read.
5232                          * so arrange for sh to be delayed a little
5233                          */
5234                         set_bit(STRIPE_DELAYED, &sh->state);
5235                         set_bit(STRIPE_HANDLE, &sh->state);
5236                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
5237                                               &sh_src->state))
5238                                 atomic_inc(&conf->preread_active_stripes);
5239                         raid5_release_stripe(sh_src);
5240                         goto finish;
5241                 }
5242                 if (sh_src)
5243                         raid5_release_stripe(sh_src);
5244
5245                 sh->reconstruct_state = reconstruct_state_idle;
5246                 clear_bit(STRIPE_EXPANDING, &sh->state);
5247                 for (i = conf->raid_disks; i--; ) {
5248                         set_bit(R5_Wantwrite, &sh->dev[i].flags);
5249                         set_bit(R5_LOCKED, &sh->dev[i].flags);
5250                         s.locked++;
5251                 }
5252         }
5253
5254         if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
5255             !sh->reconstruct_state) {
5256                 /* Need to write out all blocks after computing parity */
5257                 sh->disks = conf->raid_disks;
5258                 stripe_set_idx(sh->sector, conf, 0, sh);
5259                 schedule_reconstruction(sh, &s, 1, 1);
5260         } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
5261                 clear_bit(STRIPE_EXPAND_READY, &sh->state);
5262                 atomic_dec(&conf->reshape_stripes);
5263                 wake_up(&conf->wait_for_overlap);
5264                 md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), 1);
5265         }
5266
5267         if (s.expanding && s.locked == 0 &&
5268             !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
5269                 handle_stripe_expansion(conf, sh);
5270
5271 finish:
5272         /* wait for this device to become unblocked */
5273         if (unlikely(s.blocked_rdev)) {
5274                 if (conf->mddev->external)
5275                         md_wait_for_blocked_rdev(s.blocked_rdev,
5276                                                  conf->mddev);
5277                 else
5278                         /* Internal metadata will immediately
5279                          * be written by raid5d, so we don't
5280                          * need to wait here.
5281                          */
5282                         rdev_dec_pending(s.blocked_rdev,
5283                                          conf->mddev);
5284         }
5285
5286         if (s.handle_bad_blocks)
5287                 for (i = disks; i--; ) {
5288                         struct md_rdev *rdev;
5289                         struct r5dev *dev = &sh->dev[i];
5290                         if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
5291                                 /* We own a safe reference to the rdev */
5292                                 rdev = conf->disks[i].rdev;
5293                                 if (!rdev_set_badblocks(rdev, sh->sector,
5294                                                         RAID5_STRIPE_SECTORS(conf), 0))
5295                                         md_error(conf->mddev, rdev);
5296                                 rdev_dec_pending(rdev, conf->mddev);
5297                         }
5298                         if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
5299                                 rdev = conf->disks[i].rdev;
5300                                 rdev_clear_badblocks(rdev, sh->sector,
5301                                                      RAID5_STRIPE_SECTORS(conf), 0);
5302                                 rdev_dec_pending(rdev, conf->mddev);
5303                         }
5304                         if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
5305                                 rdev = conf->disks[i].replacement;
5306                                 if (!rdev)
5307                                         /* rdev have been moved down */
5308                                         rdev = conf->disks[i].rdev;
5309                                 rdev_clear_badblocks(rdev, sh->sector,
5310                                                      RAID5_STRIPE_SECTORS(conf), 0);
5311                                 rdev_dec_pending(rdev, conf->mddev);
5312                         }
5313                 }
5314
5315         if (s.ops_request)
5316                 raid_run_ops(sh, s.ops_request);
5317
5318         ops_run_io(sh, &s);
5319
5320         if (s.dec_preread_active) {
5321                 /* We delay this until after ops_run_io so that if make_request
5322                  * is waiting on a flush, it won't continue until the writes
5323                  * have actually been submitted.
5324                  */
5325                 atomic_dec(&conf->preread_active_stripes);
5326                 if (atomic_read(&conf->preread_active_stripes) <
5327                     IO_THRESHOLD)
5328                         md_wakeup_thread(conf->mddev->thread);
5329         }
5330
5331         clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
5332 }
5333
5334 static void raid5_activate_delayed(struct r5conf *conf)
5335         __must_hold(&conf->device_lock)
5336 {
5337         if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
5338                 while (!list_empty(&conf->delayed_list)) {
5339                         struct list_head *l = conf->delayed_list.next;
5340                         struct stripe_head *sh;
5341                         sh = list_entry(l, struct stripe_head, lru);
5342                         list_del_init(l);
5343                         clear_bit(STRIPE_DELAYED, &sh->state);
5344                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5345                                 atomic_inc(&conf->preread_active_stripes);
5346                         list_add_tail(&sh->lru, &conf->hold_list);
5347                         raid5_wakeup_stripe_thread(sh);
5348                 }
5349         }
5350 }
5351
5352 static void activate_bit_delay(struct r5conf *conf,
5353                 struct list_head *temp_inactive_list)
5354         __must_hold(&conf->device_lock)
5355 {
5356         struct list_head head;
5357         list_add(&head, &conf->bitmap_list);
5358         list_del_init(&conf->bitmap_list);
5359         while (!list_empty(&head)) {
5360                 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
5361                 int hash;
5362                 list_del_init(&sh->lru);
5363                 atomic_inc(&sh->count);
5364                 hash = sh->hash_lock_index;
5365                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
5366         }
5367 }
5368
5369 static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
5370 {
5371         struct r5conf *conf = mddev->private;
5372         sector_t sector = bio->bi_iter.bi_sector;
5373         unsigned int chunk_sectors;
5374         unsigned int bio_sectors = bio_sectors(bio);
5375
5376         chunk_sectors = min(conf->chunk_sectors, conf->prev_chunk_sectors);
5377         return  chunk_sectors >=
5378                 ((sector & (chunk_sectors - 1)) + bio_sectors);
5379 }
5380
5381 /*
5382  *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
5383  *  later sampled by raid5d.
5384  */
5385 static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
5386 {
5387         unsigned long flags;
5388
5389         spin_lock_irqsave(&conf->device_lock, flags);
5390
5391         bi->bi_next = conf->retry_read_aligned_list;
5392         conf->retry_read_aligned_list = bi;
5393
5394         spin_unlock_irqrestore(&conf->device_lock, flags);
5395         md_wakeup_thread(conf->mddev->thread);
5396 }
5397
5398 static struct bio *remove_bio_from_retry(struct r5conf *conf,
5399                                          unsigned int *offset)
5400 {
5401         struct bio *bi;
5402
5403         bi = conf->retry_read_aligned;
5404         if (bi) {
5405                 *offset = conf->retry_read_offset;
5406                 conf->retry_read_aligned = NULL;
5407                 return bi;
5408         }
5409         bi = conf->retry_read_aligned_list;
5410         if(bi) {
5411                 conf->retry_read_aligned_list = bi->bi_next;
5412                 bi->bi_next = NULL;
5413                 *offset = 0;
5414         }
5415
5416         return bi;
5417 }
5418
5419 /*
5420  *  The "raid5_align_endio" should check if the read succeeded and if it
5421  *  did, call bio_endio on the original bio (having bio_put the new bio
5422  *  first).
5423  *  If the read failed..
5424  */
5425 static void raid5_align_endio(struct bio *bi)
5426 {
5427         struct bio *raid_bi = bi->bi_private;
5428         struct md_rdev *rdev = (void *)raid_bi->bi_next;
5429         struct mddev *mddev = rdev->mddev;
5430         struct r5conf *conf = mddev->private;
5431         blk_status_t error = bi->bi_status;
5432
5433         bio_put(bi);
5434         raid_bi->bi_next = NULL;
5435         rdev_dec_pending(rdev, conf->mddev);
5436
5437         if (!error) {
5438                 bio_endio(raid_bi);
5439                 if (atomic_dec_and_test(&conf->active_aligned_reads))
5440                         wake_up(&conf->wait_for_quiescent);
5441                 return;
5442         }
5443
5444         pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
5445
5446         add_bio_to_retry(raid_bi, conf);
5447 }
5448
5449 static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
5450 {
5451         struct r5conf *conf = mddev->private;
5452         struct bio *align_bio;
5453         struct md_rdev *rdev;
5454         sector_t sector, end_sector;
5455         int dd_idx;
5456         bool did_inc;
5457
5458         if (!in_chunk_boundary(mddev, raid_bio)) {
5459                 pr_debug("%s: non aligned\n", __func__);
5460                 return 0;
5461         }
5462
5463         sector = raid5_compute_sector(conf, raid_bio->bi_iter.bi_sector, 0,
5464                                       &dd_idx, NULL);
5465         end_sector = sector + bio_sectors(raid_bio);
5466
5467         if (r5c_big_stripe_cached(conf, sector))
5468                 return 0;
5469
5470         rdev = conf->disks[dd_idx].replacement;
5471         if (!rdev || test_bit(Faulty, &rdev->flags) ||
5472             rdev->recovery_offset < end_sector) {
5473                 rdev = conf->disks[dd_idx].rdev;
5474                 if (!rdev)
5475                         return 0;
5476                 if (test_bit(Faulty, &rdev->flags) ||
5477                     !(test_bit(In_sync, &rdev->flags) ||
5478                       rdev->recovery_offset >= end_sector))
5479                         return 0;
5480         }
5481
5482         atomic_inc(&rdev->nr_pending);
5483
5484         if (rdev_has_badblock(rdev, sector, bio_sectors(raid_bio))) {
5485                 rdev_dec_pending(rdev, mddev);
5486                 return 0;
5487         }
5488
5489         md_account_bio(mddev, &raid_bio);
5490         raid_bio->bi_next = (void *)rdev;
5491
5492         align_bio = bio_alloc_clone(rdev->bdev, raid_bio, GFP_NOIO,
5493                                     &mddev->bio_set);
5494         align_bio->bi_end_io = raid5_align_endio;
5495         align_bio->bi_private = raid_bio;
5496         align_bio->bi_iter.bi_sector = sector;
5497
5498         /* No reshape active, so we can trust rdev->data_offset */
5499         align_bio->bi_iter.bi_sector += rdev->data_offset;
5500
5501         did_inc = false;
5502         if (conf->quiesce == 0) {
5503                 atomic_inc(&conf->active_aligned_reads);
5504                 did_inc = true;
5505         }
5506         /* need a memory barrier to detect the race with raid5_quiesce() */
5507         if (!did_inc || smp_load_acquire(&conf->quiesce) != 0) {
5508                 /* quiesce is in progress, so we need to undo io activation and wait
5509                  * for it to finish
5510                  */
5511                 if (did_inc && atomic_dec_and_test(&conf->active_aligned_reads))
5512                         wake_up(&conf->wait_for_quiescent);
5513                 spin_lock_irq(&conf->device_lock);
5514                 wait_event_lock_irq(conf->wait_for_quiescent, conf->quiesce == 0,
5515                                     conf->device_lock);
5516                 atomic_inc(&conf->active_aligned_reads);
5517                 spin_unlock_irq(&conf->device_lock);
5518         }
5519
5520         mddev_trace_remap(mddev, align_bio, raid_bio->bi_iter.bi_sector);
5521         submit_bio_noacct(align_bio);
5522         return 1;
5523 }
5524
5525 static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
5526 {
5527         struct bio *split;
5528         sector_t sector = raid_bio->bi_iter.bi_sector;
5529         unsigned chunk_sects = mddev->chunk_sectors;
5530         unsigned sectors = chunk_sects - (sector & (chunk_sects-1));
5531
5532         if (sectors < bio_sectors(raid_bio)) {
5533                 struct r5conf *conf = mddev->private;
5534                 split = bio_split(raid_bio, sectors, GFP_NOIO, &conf->bio_split);
5535                 bio_chain(split, raid_bio);
5536                 submit_bio_noacct(raid_bio);
5537                 raid_bio = split;
5538         }
5539
5540         if (!raid5_read_one_chunk(mddev, raid_bio))
5541                 return raid_bio;
5542
5543         return NULL;
5544 }
5545
5546 /* __get_priority_stripe - get the next stripe to process
5547  *
5548  * Full stripe writes are allowed to pass preread active stripes up until
5549  * the bypass_threshold is exceeded.  In general the bypass_count
5550  * increments when the handle_list is handled before the hold_list; however, it
5551  * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
5552  * stripe with in flight i/o.  The bypass_count will be reset when the
5553  * head of the hold_list has changed, i.e. the head was promoted to the
5554  * handle_list.
5555  */
5556 static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group)
5557         __must_hold(&conf->device_lock)
5558 {
5559         struct stripe_head *sh, *tmp;
5560         struct list_head *handle_list = NULL;
5561         struct r5worker_group *wg;
5562         bool second_try = !r5c_is_writeback(conf->log) &&
5563                 !r5l_log_disk_error(conf);
5564         bool try_loprio = test_bit(R5C_LOG_TIGHT, &conf->cache_state) ||
5565                 r5l_log_disk_error(conf);
5566
5567 again:
5568         wg = NULL;
5569         sh = NULL;
5570         if (conf->worker_cnt_per_group == 0) {
5571                 handle_list = try_loprio ? &conf->loprio_list :
5572                                         &conf->handle_list;
5573         } else if (group != ANY_GROUP) {
5574                 handle_list = try_loprio ? &conf->worker_groups[group].loprio_list :
5575                                 &conf->worker_groups[group].handle_list;
5576                 wg = &conf->worker_groups[group];
5577         } else {
5578                 int i;
5579                 for (i = 0; i < conf->group_cnt; i++) {
5580                         handle_list = try_loprio ? &conf->worker_groups[i].loprio_list :
5581                                 &conf->worker_groups[i].handle_list;
5582                         wg = &conf->worker_groups[i];
5583                         if (!list_empty(handle_list))
5584                                 break;
5585                 }
5586         }
5587
5588         pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
5589                   __func__,
5590                   list_empty(handle_list) ? "empty" : "busy",
5591                   list_empty(&conf->hold_list) ? "empty" : "busy",
5592                   atomic_read(&conf->pending_full_writes), conf->bypass_count);
5593
5594         if (!list_empty(handle_list)) {
5595                 sh = list_entry(handle_list->next, typeof(*sh), lru);
5596
5597                 if (list_empty(&conf->hold_list))
5598                         conf->bypass_count = 0;
5599                 else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
5600                         if (conf->hold_list.next == conf->last_hold)
5601                                 conf->bypass_count++;
5602                         else {
5603                                 conf->last_hold = conf->hold_list.next;
5604                                 conf->bypass_count -= conf->bypass_threshold;
5605                                 if (conf->bypass_count < 0)
5606                                         conf->bypass_count = 0;
5607                         }
5608                 }
5609         } else if (!list_empty(&conf->hold_list) &&
5610                    ((conf->bypass_threshold &&
5611                      conf->bypass_count > conf->bypass_threshold) ||
5612                     atomic_read(&conf->pending_full_writes) == 0)) {
5613
5614                 list_for_each_entry(tmp, &conf->hold_list,  lru) {
5615                         if (conf->worker_cnt_per_group == 0 ||
5616                             group == ANY_GROUP ||
5617                             !cpu_online(tmp->cpu) ||
5618                             cpu_to_group(tmp->cpu) == group) {
5619                                 sh = tmp;
5620                                 break;
5621                         }
5622                 }
5623
5624                 if (sh) {
5625                         conf->bypass_count -= conf->bypass_threshold;
5626                         if (conf->bypass_count < 0)
5627                                 conf->bypass_count = 0;
5628                 }
5629                 wg = NULL;
5630         }
5631
5632         if (!sh) {
5633                 if (second_try)
5634                         return NULL;
5635                 second_try = true;
5636                 try_loprio = !try_loprio;
5637                 goto again;
5638         }
5639
5640         if (wg) {
5641                 wg->stripes_cnt--;
5642                 sh->group = NULL;
5643         }
5644         list_del_init(&sh->lru);
5645         BUG_ON(atomic_inc_return(&sh->count) != 1);
5646         return sh;
5647 }
5648
5649 struct raid5_plug_cb {
5650         struct blk_plug_cb      cb;
5651         struct list_head        list;
5652         struct list_head        temp_inactive_list[NR_STRIPE_HASH_LOCKS];
5653 };
5654
5655 static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
5656 {
5657         struct raid5_plug_cb *cb = container_of(
5658                 blk_cb, struct raid5_plug_cb, cb);
5659         struct stripe_head *sh;
5660         struct mddev *mddev = cb->cb.data;
5661         struct r5conf *conf = mddev->private;
5662         int cnt = 0;
5663         int hash;
5664
5665         if (cb->list.next && !list_empty(&cb->list)) {
5666                 spin_lock_irq(&conf->device_lock);
5667                 while (!list_empty(&cb->list)) {
5668                         sh = list_first_entry(&cb->list, struct stripe_head, lru);
5669                         list_del_init(&sh->lru);
5670                         /*
5671                          * avoid race release_stripe_plug() sees
5672                          * STRIPE_ON_UNPLUG_LIST clear but the stripe
5673                          * is still in our list
5674                          */
5675                         smp_mb__before_atomic();
5676                         clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
5677                         /*
5678                          * STRIPE_ON_RELEASE_LIST could be set here. In that
5679                          * case, the count is always > 1 here
5680                          */
5681                         hash = sh->hash_lock_index;
5682                         __release_stripe(conf, sh, &cb->temp_inactive_list[hash]);
5683                         cnt++;
5684                 }
5685                 spin_unlock_irq(&conf->device_lock);
5686         }
5687         release_inactive_stripe_list(conf, cb->temp_inactive_list,
5688                                      NR_STRIPE_HASH_LOCKS);
5689         if (!mddev_is_dm(mddev))
5690                 trace_block_unplug(mddev->gendisk->queue, cnt, !from_schedule);
5691         kfree(cb);
5692 }
5693
5694 static void release_stripe_plug(struct mddev *mddev,
5695                                 struct stripe_head *sh)
5696 {
5697         struct blk_plug_cb *blk_cb = blk_check_plugged(
5698                 raid5_unplug, mddev,
5699                 sizeof(struct raid5_plug_cb));
5700         struct raid5_plug_cb *cb;
5701
5702         if (!blk_cb) {
5703                 raid5_release_stripe(sh);
5704                 return;
5705         }
5706
5707         cb = container_of(blk_cb, struct raid5_plug_cb, cb);
5708
5709         if (cb->list.next == NULL) {
5710                 int i;
5711                 INIT_LIST_HEAD(&cb->list);
5712                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
5713                         INIT_LIST_HEAD(cb->temp_inactive_list + i);
5714         }
5715
5716         if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
5717                 list_add_tail(&sh->lru, &cb->list);
5718         else
5719                 raid5_release_stripe(sh);
5720 }
5721
5722 static void make_discard_request(struct mddev *mddev, struct bio *bi)
5723 {
5724         struct r5conf *conf = mddev->private;
5725         sector_t logical_sector, last_sector;
5726         struct stripe_head *sh;
5727         int stripe_sectors;
5728
5729         /* We need to handle this when io_uring supports discard/trim */
5730         if (WARN_ON_ONCE(bi->bi_opf & REQ_NOWAIT))
5731                 return;
5732
5733         if (mddev->reshape_position != MaxSector)
5734                 /* Skip discard while reshape is happening */
5735                 return;
5736
5737         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
5738         last_sector = bio_end_sector(bi);
5739
5740         bi->bi_next = NULL;
5741
5742         stripe_sectors = conf->chunk_sectors *
5743                 (conf->raid_disks - conf->max_degraded);
5744         logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
5745                                                stripe_sectors);
5746         sector_div(last_sector, stripe_sectors);
5747
5748         logical_sector *= conf->chunk_sectors;
5749         last_sector *= conf->chunk_sectors;
5750
5751         for (; logical_sector < last_sector;
5752              logical_sector += RAID5_STRIPE_SECTORS(conf)) {
5753                 DEFINE_WAIT(w);
5754                 int d;
5755         again:
5756                 sh = raid5_get_active_stripe(conf, NULL, logical_sector, 0);
5757                 prepare_to_wait(&conf->wait_for_overlap, &w,
5758                                 TASK_UNINTERRUPTIBLE);
5759                 set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5760                 if (test_bit(STRIPE_SYNCING, &sh->state)) {
5761                         raid5_release_stripe(sh);
5762                         schedule();
5763                         goto again;
5764                 }
5765                 clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5766                 spin_lock_irq(&sh->stripe_lock);
5767                 for (d = 0; d < conf->raid_disks; d++) {
5768                         if (d == sh->pd_idx || d == sh->qd_idx)
5769                                 continue;
5770                         if (sh->dev[d].towrite || sh->dev[d].toread) {
5771                                 set_bit(R5_Overlap, &sh->dev[d].flags);
5772                                 spin_unlock_irq(&sh->stripe_lock);
5773                                 raid5_release_stripe(sh);
5774                                 schedule();
5775                                 goto again;
5776                         }
5777                 }
5778                 set_bit(STRIPE_DISCARD, &sh->state);
5779                 finish_wait(&conf->wait_for_overlap, &w);
5780                 sh->overwrite_disks = 0;
5781                 for (d = 0; d < conf->raid_disks; d++) {
5782                         if (d == sh->pd_idx || d == sh->qd_idx)
5783                                 continue;
5784                         sh->dev[d].towrite = bi;
5785                         set_bit(R5_OVERWRITE, &sh->dev[d].flags);
5786                         bio_inc_remaining(bi);
5787                         md_write_inc(mddev, bi);
5788                         sh->overwrite_disks++;
5789                 }
5790                 spin_unlock_irq(&sh->stripe_lock);
5791                 if (conf->mddev->bitmap) {
5792                         for (d = 0;
5793                              d < conf->raid_disks - conf->max_degraded;
5794                              d++)
5795                                 md_bitmap_startwrite(mddev->bitmap,
5796                                                      sh->sector,
5797                                                      RAID5_STRIPE_SECTORS(conf),
5798                                                      0);
5799                         sh->bm_seq = conf->seq_flush + 1;
5800                         set_bit(STRIPE_BIT_DELAY, &sh->state);
5801                 }
5802
5803                 set_bit(STRIPE_HANDLE, &sh->state);
5804                 clear_bit(STRIPE_DELAYED, &sh->state);
5805                 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5806                         atomic_inc(&conf->preread_active_stripes);
5807                 release_stripe_plug(mddev, sh);
5808         }
5809
5810         bio_endio(bi);
5811 }
5812
5813 static bool ahead_of_reshape(struct mddev *mddev, sector_t sector,
5814                              sector_t reshape_sector)
5815 {
5816         return mddev->reshape_backwards ? sector < reshape_sector :
5817                                           sector >= reshape_sector;
5818 }
5819
5820 static bool range_ahead_of_reshape(struct mddev *mddev, sector_t min,
5821                                    sector_t max, sector_t reshape_sector)
5822 {
5823         return mddev->reshape_backwards ? max < reshape_sector :
5824                                           min >= reshape_sector;
5825 }
5826
5827 static bool stripe_ahead_of_reshape(struct mddev *mddev, struct r5conf *conf,
5828                                     struct stripe_head *sh)
5829 {
5830         sector_t max_sector = 0, min_sector = MaxSector;
5831         bool ret = false;
5832         int dd_idx;
5833
5834         for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) {
5835                 if (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
5836                         continue;
5837
5838                 min_sector = min(min_sector, sh->dev[dd_idx].sector);
5839                 max_sector = max(max_sector, sh->dev[dd_idx].sector);
5840         }
5841
5842         spin_lock_irq(&conf->device_lock);
5843
5844         if (!range_ahead_of_reshape(mddev, min_sector, max_sector,
5845                                      conf->reshape_progress))
5846                 /* mismatch, need to try again */
5847                 ret = true;
5848
5849         spin_unlock_irq(&conf->device_lock);
5850
5851         return ret;
5852 }
5853
5854 static int add_all_stripe_bios(struct r5conf *conf,
5855                 struct stripe_request_ctx *ctx, struct stripe_head *sh,
5856                 struct bio *bi, int forwrite, int previous)
5857 {
5858         int dd_idx;
5859         int ret = 1;
5860
5861         spin_lock_irq(&sh->stripe_lock);
5862
5863         for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) {
5864                 struct r5dev *dev = &sh->dev[dd_idx];
5865
5866                 if (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
5867                         continue;
5868
5869                 if (dev->sector < ctx->first_sector ||
5870                     dev->sector >= ctx->last_sector)
5871                         continue;
5872
5873                 if (stripe_bio_overlaps(sh, bi, dd_idx, forwrite)) {
5874                         set_bit(R5_Overlap, &dev->flags);
5875                         ret = 0;
5876                         continue;
5877                 }
5878         }
5879
5880         if (!ret)
5881                 goto out;
5882
5883         for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) {
5884                 struct r5dev *dev = &sh->dev[dd_idx];
5885
5886                 if (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
5887                         continue;
5888
5889                 if (dev->sector < ctx->first_sector ||
5890                     dev->sector >= ctx->last_sector)
5891                         continue;
5892
5893                 __add_stripe_bio(sh, bi, dd_idx, forwrite, previous);
5894                 clear_bit((dev->sector - ctx->first_sector) >>
5895                           RAID5_STRIPE_SHIFT(conf), ctx->sectors_to_do);
5896         }
5897
5898 out:
5899         spin_unlock_irq(&sh->stripe_lock);
5900         return ret;
5901 }
5902
5903 static enum stripe_result make_stripe_request(struct mddev *mddev,
5904                 struct r5conf *conf, struct stripe_request_ctx *ctx,
5905                 sector_t logical_sector, struct bio *bi)
5906 {
5907         const int rw = bio_data_dir(bi);
5908         enum stripe_result ret;
5909         struct stripe_head *sh;
5910         sector_t new_sector;
5911         int previous = 0, flags = 0;
5912         int seq, dd_idx;
5913
5914         seq = read_seqcount_begin(&conf->gen_lock);
5915
5916         if (unlikely(conf->reshape_progress != MaxSector)) {
5917                 /*
5918                  * Spinlock is needed as reshape_progress may be
5919                  * 64bit on a 32bit platform, and so it might be
5920                  * possible to see a half-updated value
5921                  * Of course reshape_progress could change after
5922                  * the lock is dropped, so once we get a reference
5923                  * to the stripe that we think it is, we will have
5924                  * to check again.
5925                  */
5926                 spin_lock_irq(&conf->device_lock);
5927                 if (ahead_of_reshape(mddev, logical_sector,
5928                                      conf->reshape_progress)) {
5929                         previous = 1;
5930                 } else {
5931                         if (ahead_of_reshape(mddev, logical_sector,
5932                                              conf->reshape_safe)) {
5933                                 spin_unlock_irq(&conf->device_lock);
5934                                 ret = STRIPE_SCHEDULE_AND_RETRY;
5935                                 goto out;
5936                         }
5937                 }
5938                 spin_unlock_irq(&conf->device_lock);
5939         }
5940
5941         new_sector = raid5_compute_sector(conf, logical_sector, previous,
5942                                           &dd_idx, NULL);
5943         pr_debug("raid456: %s, sector %llu logical %llu\n", __func__,
5944                  new_sector, logical_sector);
5945
5946         if (previous)
5947                 flags |= R5_GAS_PREVIOUS;
5948         if (bi->bi_opf & REQ_RAHEAD)
5949                 flags |= R5_GAS_NOBLOCK;
5950         sh = raid5_get_active_stripe(conf, ctx, new_sector, flags);
5951         if (unlikely(!sh)) {
5952                 /* cannot get stripe, just give-up */
5953                 bi->bi_status = BLK_STS_IOERR;
5954                 return STRIPE_FAIL;
5955         }
5956
5957         if (unlikely(previous) &&
5958             stripe_ahead_of_reshape(mddev, conf, sh)) {
5959                 /*
5960                  * Expansion moved on while waiting for a stripe.
5961                  * Expansion could still move past after this
5962                  * test, but as we are holding a reference to
5963                  * 'sh', we know that if that happens,
5964                  *  STRIPE_EXPANDING will get set and the expansion
5965                  * won't proceed until we finish with the stripe.
5966                  */
5967                 ret = STRIPE_SCHEDULE_AND_RETRY;
5968                 goto out_release;
5969         }
5970
5971         if (read_seqcount_retry(&conf->gen_lock, seq)) {
5972                 /* Might have got the wrong stripe_head by accident */
5973                 ret = STRIPE_RETRY;
5974                 goto out_release;
5975         }
5976
5977         if (test_bit(STRIPE_EXPANDING, &sh->state) ||
5978             !add_all_stripe_bios(conf, ctx, sh, bi, rw, previous)) {
5979                 /*
5980                  * Stripe is busy expanding or add failed due to
5981                  * overlap. Flush everything and wait a while.
5982                  */
5983                 md_wakeup_thread(mddev->thread);
5984                 ret = STRIPE_SCHEDULE_AND_RETRY;
5985                 goto out_release;
5986         }
5987
5988         if (stripe_can_batch(sh)) {
5989                 stripe_add_to_batch_list(conf, sh, ctx->batch_last);
5990                 if (ctx->batch_last)
5991                         raid5_release_stripe(ctx->batch_last);
5992                 atomic_inc(&sh->count);
5993                 ctx->batch_last = sh;
5994         }
5995
5996         if (ctx->do_flush) {
5997                 set_bit(STRIPE_R5C_PREFLUSH, &sh->state);
5998                 /* we only need flush for one stripe */
5999                 ctx->do_flush = false;
6000         }
6001
6002         set_bit(STRIPE_HANDLE, &sh->state);
6003         clear_bit(STRIPE_DELAYED, &sh->state);
6004         if ((!sh->batch_head || sh == sh->batch_head) &&
6005             (bi->bi_opf & REQ_SYNC) &&
6006             !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
6007                 atomic_inc(&conf->preread_active_stripes);
6008
6009         release_stripe_plug(mddev, sh);
6010         return STRIPE_SUCCESS;
6011
6012 out_release:
6013         raid5_release_stripe(sh);
6014 out:
6015         if (ret == STRIPE_SCHEDULE_AND_RETRY && reshape_interrupted(mddev)) {
6016                 bi->bi_status = BLK_STS_RESOURCE;
6017                 ret = STRIPE_WAIT_RESHAPE;
6018                 pr_err_ratelimited("dm-raid456: io across reshape position while reshape can't make progress");
6019         }
6020         return ret;
6021 }
6022
6023 /*
6024  * If the bio covers multiple data disks, find sector within the bio that has
6025  * the lowest chunk offset in the first chunk.
6026  */
6027 static sector_t raid5_bio_lowest_chunk_sector(struct r5conf *conf,
6028                                               struct bio *bi)
6029 {
6030         int sectors_per_chunk = conf->chunk_sectors;
6031         int raid_disks = conf->raid_disks;
6032         int dd_idx;
6033         struct stripe_head sh;
6034         unsigned int chunk_offset;
6035         sector_t r_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
6036         sector_t sector;
6037
6038         /* We pass in fake stripe_head to get back parity disk numbers */
6039         sector = raid5_compute_sector(conf, r_sector, 0, &dd_idx, &sh);
6040         chunk_offset = sector_div(sector, sectors_per_chunk);
6041         if (sectors_per_chunk - chunk_offset >= bio_sectors(bi))
6042                 return r_sector;
6043         /*
6044          * Bio crosses to the next data disk. Check whether it's in the same
6045          * chunk.
6046          */
6047         dd_idx++;
6048         while (dd_idx == sh.pd_idx || dd_idx == sh.qd_idx)
6049                 dd_idx++;
6050         if (dd_idx >= raid_disks)
6051                 return r_sector;
6052         return r_sector + sectors_per_chunk - chunk_offset;
6053 }
6054
6055 static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
6056 {
6057         DEFINE_WAIT_FUNC(wait, woken_wake_function);
6058         struct r5conf *conf = mddev->private;
6059         sector_t logical_sector;
6060         struct stripe_request_ctx ctx = {};
6061         const int rw = bio_data_dir(bi);
6062         enum stripe_result res;
6063         int s, stripe_cnt;
6064
6065         if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
6066                 int ret = log_handle_flush_request(conf, bi);
6067
6068                 if (ret == 0)
6069                         return true;
6070                 if (ret == -ENODEV) {
6071                         if (md_flush_request(mddev, bi))
6072                                 return true;
6073                 }
6074                 /* ret == -EAGAIN, fallback */
6075                 /*
6076                  * if r5l_handle_flush_request() didn't clear REQ_PREFLUSH,
6077                  * we need to flush journal device
6078                  */
6079                 ctx.do_flush = bi->bi_opf & REQ_PREFLUSH;
6080         }
6081
6082         if (!md_write_start(mddev, bi))
6083                 return false;
6084         /*
6085          * If array is degraded, better not do chunk aligned read because
6086          * later we might have to read it again in order to reconstruct
6087          * data on failed drives.
6088          */
6089         if (rw == READ && mddev->degraded == 0 &&
6090             mddev->reshape_position == MaxSector) {
6091                 bi = chunk_aligned_read(mddev, bi);
6092                 if (!bi)
6093                         return true;
6094         }
6095
6096         if (unlikely(bio_op(bi) == REQ_OP_DISCARD)) {
6097                 make_discard_request(mddev, bi);
6098                 md_write_end(mddev);
6099                 return true;
6100         }
6101
6102         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
6103         ctx.first_sector = logical_sector;
6104         ctx.last_sector = bio_end_sector(bi);
6105         bi->bi_next = NULL;
6106
6107         stripe_cnt = DIV_ROUND_UP_SECTOR_T(ctx.last_sector - logical_sector,
6108                                            RAID5_STRIPE_SECTORS(conf));
6109         bitmap_set(ctx.sectors_to_do, 0, stripe_cnt);
6110
6111         pr_debug("raid456: %s, logical %llu to %llu\n", __func__,
6112                  bi->bi_iter.bi_sector, ctx.last_sector);
6113
6114         /* Bail out if conflicts with reshape and REQ_NOWAIT is set */
6115         if ((bi->bi_opf & REQ_NOWAIT) &&
6116             (conf->reshape_progress != MaxSector) &&
6117             !ahead_of_reshape(mddev, logical_sector, conf->reshape_progress) &&
6118             ahead_of_reshape(mddev, logical_sector, conf->reshape_safe)) {
6119                 bio_wouldblock_error(bi);
6120                 if (rw == WRITE)
6121                         md_write_end(mddev);
6122                 return true;
6123         }
6124         md_account_bio(mddev, &bi);
6125
6126         /*
6127          * Lets start with the stripe with the lowest chunk offset in the first
6128          * chunk. That has the best chances of creating IOs adjacent to
6129          * previous IOs in case of sequential IO and thus creates the most
6130          * sequential IO pattern. We don't bother with the optimization when
6131          * reshaping as the performance benefit is not worth the complexity.
6132          */
6133         if (likely(conf->reshape_progress == MaxSector))
6134                 logical_sector = raid5_bio_lowest_chunk_sector(conf, bi);
6135         s = (logical_sector - ctx.first_sector) >> RAID5_STRIPE_SHIFT(conf);
6136
6137         add_wait_queue(&conf->wait_for_overlap, &wait);
6138         while (1) {
6139                 res = make_stripe_request(mddev, conf, &ctx, logical_sector,
6140                                           bi);
6141                 if (res == STRIPE_FAIL || res == STRIPE_WAIT_RESHAPE)
6142                         break;
6143
6144                 if (res == STRIPE_RETRY)
6145                         continue;
6146
6147                 if (res == STRIPE_SCHEDULE_AND_RETRY) {
6148                         /*
6149                          * Must release the reference to batch_last before
6150                          * scheduling and waiting for work to be done,
6151                          * otherwise the batch_last stripe head could prevent
6152                          * raid5_activate_delayed() from making progress
6153                          * and thus deadlocking.
6154                          */
6155                         if (ctx.batch_last) {
6156                                 raid5_release_stripe(ctx.batch_last);
6157                                 ctx.batch_last = NULL;
6158                         }
6159
6160                         wait_woken(&wait, TASK_UNINTERRUPTIBLE,
6161                                    MAX_SCHEDULE_TIMEOUT);
6162                         continue;
6163                 }
6164
6165                 s = find_next_bit_wrap(ctx.sectors_to_do, stripe_cnt, s);
6166                 if (s == stripe_cnt)
6167                         break;
6168
6169                 logical_sector = ctx.first_sector +
6170                         (s << RAID5_STRIPE_SHIFT(conf));
6171         }
6172         remove_wait_queue(&conf->wait_for_overlap, &wait);
6173
6174         if (ctx.batch_last)
6175                 raid5_release_stripe(ctx.batch_last);
6176
6177         if (rw == WRITE)
6178                 md_write_end(mddev);
6179         if (res == STRIPE_WAIT_RESHAPE) {
6180                 md_free_cloned_bio(bi);
6181                 return false;
6182         }
6183
6184         bio_endio(bi);
6185         return true;
6186 }
6187
6188 static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
6189
6190 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
6191 {
6192         /* reshaping is quite different to recovery/resync so it is
6193          * handled quite separately ... here.
6194          *
6195          * On each call to sync_request, we gather one chunk worth of
6196          * destination stripes and flag them as expanding.
6197          * Then we find all the source stripes and request reads.
6198          * As the reads complete, handle_stripe will copy the data
6199          * into the destination stripe and release that stripe.
6200          */
6201         struct r5conf *conf = mddev->private;
6202         struct stripe_head *sh;
6203         struct md_rdev *rdev;
6204         sector_t first_sector, last_sector;
6205         int raid_disks = conf->previous_raid_disks;
6206         int data_disks = raid_disks - conf->max_degraded;
6207         int new_data_disks = conf->raid_disks - conf->max_degraded;
6208         int i;
6209         int dd_idx;
6210         sector_t writepos, readpos, safepos;
6211         sector_t stripe_addr;
6212         int reshape_sectors;
6213         struct list_head stripes;
6214         sector_t retn;
6215
6216         if (sector_nr == 0) {
6217                 /* If restarting in the middle, skip the initial sectors */
6218                 if (mddev->reshape_backwards &&
6219                     conf->reshape_progress < raid5_size(mddev, 0, 0)) {
6220                         sector_nr = raid5_size(mddev, 0, 0)
6221                                 - conf->reshape_progress;
6222                 } else if (mddev->reshape_backwards &&
6223                            conf->reshape_progress == MaxSector) {
6224                         /* shouldn't happen, but just in case, finish up.*/
6225                         sector_nr = MaxSector;
6226                 } else if (!mddev->reshape_backwards &&
6227                            conf->reshape_progress > 0)
6228                         sector_nr = conf->reshape_progress;
6229                 sector_div(sector_nr, new_data_disks);
6230                 if (sector_nr) {
6231                         mddev->curr_resync_completed = sector_nr;
6232                         sysfs_notify_dirent_safe(mddev->sysfs_completed);
6233                         *skipped = 1;
6234                         retn = sector_nr;
6235                         goto finish;
6236                 }
6237         }
6238
6239         /* We need to process a full chunk at a time.
6240          * If old and new chunk sizes differ, we need to process the
6241          * largest of these
6242          */
6243
6244         reshape_sectors = max(conf->chunk_sectors, conf->prev_chunk_sectors);
6245
6246         /* We update the metadata at least every 10 seconds, or when
6247          * the data about to be copied would over-write the source of
6248          * the data at the front of the range.  i.e. one new_stripe
6249          * along from reshape_progress new_maps to after where
6250          * reshape_safe old_maps to
6251          */
6252         writepos = conf->reshape_progress;
6253         sector_div(writepos, new_data_disks);
6254         readpos = conf->reshape_progress;
6255         sector_div(readpos, data_disks);
6256         safepos = conf->reshape_safe;
6257         sector_div(safepos, data_disks);
6258         if (mddev->reshape_backwards) {
6259                 BUG_ON(writepos < reshape_sectors);
6260                 writepos -= reshape_sectors;
6261                 readpos += reshape_sectors;
6262                 safepos += reshape_sectors;
6263         } else {
6264                 writepos += reshape_sectors;
6265                 /* readpos and safepos are worst-case calculations.
6266                  * A negative number is overly pessimistic, and causes
6267                  * obvious problems for unsigned storage.  So clip to 0.
6268                  */
6269                 readpos -= min_t(sector_t, reshape_sectors, readpos);
6270                 safepos -= min_t(sector_t, reshape_sectors, safepos);
6271         }
6272
6273         /* Having calculated the 'writepos' possibly use it
6274          * to set 'stripe_addr' which is where we will write to.
6275          */
6276         if (mddev->reshape_backwards) {
6277                 BUG_ON(conf->reshape_progress == 0);
6278                 stripe_addr = writepos;
6279                 BUG_ON((mddev->dev_sectors &
6280                         ~((sector_t)reshape_sectors - 1))
6281                        - reshape_sectors - stripe_addr
6282                        != sector_nr);
6283         } else {
6284                 BUG_ON(writepos != sector_nr + reshape_sectors);
6285                 stripe_addr = sector_nr;
6286         }
6287
6288         /* 'writepos' is the most advanced device address we might write.
6289          * 'readpos' is the least advanced device address we might read.
6290          * 'safepos' is the least address recorded in the metadata as having
6291          *     been reshaped.
6292          * If there is a min_offset_diff, these are adjusted either by
6293          * increasing the safepos/readpos if diff is negative, or
6294          * increasing writepos if diff is positive.
6295          * If 'readpos' is then behind 'writepos', there is no way that we can
6296          * ensure safety in the face of a crash - that must be done by userspace
6297          * making a backup of the data.  So in that case there is no particular
6298          * rush to update metadata.
6299          * Otherwise if 'safepos' is behind 'writepos', then we really need to
6300          * update the metadata to advance 'safepos' to match 'readpos' so that
6301          * we can be safe in the event of a crash.
6302          * So we insist on updating metadata if safepos is behind writepos and
6303          * readpos is beyond writepos.
6304          * In any case, update the metadata every 10 seconds.
6305          * Maybe that number should be configurable, but I'm not sure it is
6306          * worth it.... maybe it could be a multiple of safemode_delay???
6307          */
6308         if (conf->min_offset_diff < 0) {
6309                 safepos += -conf->min_offset_diff;
6310                 readpos += -conf->min_offset_diff;
6311         } else
6312                 writepos += conf->min_offset_diff;
6313
6314         if ((mddev->reshape_backwards
6315              ? (safepos > writepos && readpos < writepos)
6316              : (safepos < writepos && readpos > writepos)) ||
6317             time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
6318                 /* Cannot proceed until we've updated the superblock... */
6319                 wait_event(conf->wait_for_overlap,
6320                            atomic_read(&conf->reshape_stripes)==0
6321                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6322                 if (atomic_read(&conf->reshape_stripes) != 0)
6323                         return 0;
6324                 mddev->reshape_position = conf->reshape_progress;
6325                 mddev->curr_resync_completed = sector_nr;
6326                 if (!mddev->reshape_backwards)
6327                         /* Can update recovery_offset */
6328                         rdev_for_each(rdev, mddev)
6329                                 if (rdev->raid_disk >= 0 &&
6330                                     !test_bit(Journal, &rdev->flags) &&
6331                                     !test_bit(In_sync, &rdev->flags) &&
6332                                     rdev->recovery_offset < sector_nr)
6333                                         rdev->recovery_offset = sector_nr;
6334
6335                 conf->reshape_checkpoint = jiffies;
6336                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
6337                 md_wakeup_thread(mddev->thread);
6338                 wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
6339                            test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6340                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6341                         return 0;
6342                 spin_lock_irq(&conf->device_lock);
6343                 conf->reshape_safe = mddev->reshape_position;
6344                 spin_unlock_irq(&conf->device_lock);
6345                 wake_up(&conf->wait_for_overlap);
6346                 sysfs_notify_dirent_safe(mddev->sysfs_completed);
6347         }
6348
6349         INIT_LIST_HEAD(&stripes);
6350         for (i = 0; i < reshape_sectors; i += RAID5_STRIPE_SECTORS(conf)) {
6351                 int j;
6352                 int skipped_disk = 0;
6353                 sh = raid5_get_active_stripe(conf, NULL, stripe_addr+i,
6354                                              R5_GAS_NOQUIESCE);
6355                 set_bit(STRIPE_EXPANDING, &sh->state);
6356                 atomic_inc(&conf->reshape_stripes);
6357                 /* If any of this stripe is beyond the end of the old
6358                  * array, then we need to zero those blocks
6359                  */
6360                 for (j=sh->disks; j--;) {
6361                         sector_t s;
6362                         if (j == sh->pd_idx)
6363                                 continue;
6364                         if (conf->level == 6 &&
6365                             j == sh->qd_idx)
6366                                 continue;
6367                         s = raid5_compute_blocknr(sh, j, 0);
6368                         if (s < raid5_size(mddev, 0, 0)) {
6369                                 skipped_disk = 1;
6370                                 continue;
6371                         }
6372                         memset(page_address(sh->dev[j].page), 0, RAID5_STRIPE_SIZE(conf));
6373                         set_bit(R5_Expanded, &sh->dev[j].flags);
6374                         set_bit(R5_UPTODATE, &sh->dev[j].flags);
6375                 }
6376                 if (!skipped_disk) {
6377                         set_bit(STRIPE_EXPAND_READY, &sh->state);
6378                         set_bit(STRIPE_HANDLE, &sh->state);
6379                 }
6380                 list_add(&sh->lru, &stripes);
6381         }
6382         spin_lock_irq(&conf->device_lock);
6383         if (mddev->reshape_backwards)
6384                 conf->reshape_progress -= reshape_sectors * new_data_disks;
6385         else
6386                 conf->reshape_progress += reshape_sectors * new_data_disks;
6387         spin_unlock_irq(&conf->device_lock);
6388         /* Ok, those stripe are ready. We can start scheduling
6389          * reads on the source stripes.
6390          * The source stripes are determined by mapping the first and last
6391          * block on the destination stripes.
6392          */
6393         first_sector =
6394                 raid5_compute_sector(conf, stripe_addr*(new_data_disks),
6395                                      1, &dd_idx, NULL);
6396         last_sector =
6397                 raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
6398                                             * new_data_disks - 1),
6399                                      1, &dd_idx, NULL);
6400         if (last_sector >= mddev->dev_sectors)
6401                 last_sector = mddev->dev_sectors - 1;
6402         while (first_sector <= last_sector) {
6403                 sh = raid5_get_active_stripe(conf, NULL, first_sector,
6404                                 R5_GAS_PREVIOUS | R5_GAS_NOQUIESCE);
6405                 set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
6406                 set_bit(STRIPE_HANDLE, &sh->state);
6407                 raid5_release_stripe(sh);
6408                 first_sector += RAID5_STRIPE_SECTORS(conf);
6409         }
6410         /* Now that the sources are clearly marked, we can release
6411          * the destination stripes
6412          */
6413         while (!list_empty(&stripes)) {
6414                 sh = list_entry(stripes.next, struct stripe_head, lru);
6415                 list_del_init(&sh->lru);
6416                 raid5_release_stripe(sh);
6417         }
6418         /* If this takes us to the resync_max point where we have to pause,
6419          * then we need to write out the superblock.
6420          */
6421         sector_nr += reshape_sectors;
6422         retn = reshape_sectors;
6423 finish:
6424         if (mddev->curr_resync_completed > mddev->resync_max ||
6425             (sector_nr - mddev->curr_resync_completed) * 2
6426             >= mddev->resync_max - mddev->curr_resync_completed) {
6427                 /* Cannot proceed until we've updated the superblock... */
6428                 wait_event(conf->wait_for_overlap,
6429                            atomic_read(&conf->reshape_stripes) == 0
6430                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6431                 if (atomic_read(&conf->reshape_stripes) != 0)
6432                         goto ret;
6433                 mddev->reshape_position = conf->reshape_progress;
6434                 mddev->curr_resync_completed = sector_nr;
6435                 if (!mddev->reshape_backwards)
6436                         /* Can update recovery_offset */
6437                         rdev_for_each(rdev, mddev)
6438                                 if (rdev->raid_disk >= 0 &&
6439                                     !test_bit(Journal, &rdev->flags) &&
6440                                     !test_bit(In_sync, &rdev->flags) &&
6441                                     rdev->recovery_offset < sector_nr)
6442                                         rdev->recovery_offset = sector_nr;
6443                 conf->reshape_checkpoint = jiffies;
6444                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
6445                 md_wakeup_thread(mddev->thread);
6446                 wait_event(mddev->sb_wait,
6447                            !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)
6448                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6449                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6450                         goto ret;
6451                 spin_lock_irq(&conf->device_lock);
6452                 conf->reshape_safe = mddev->reshape_position;
6453                 spin_unlock_irq(&conf->device_lock);
6454                 wake_up(&conf->wait_for_overlap);
6455                 sysfs_notify_dirent_safe(mddev->sysfs_completed);
6456         }
6457 ret:
6458         return retn;
6459 }
6460
6461 static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_nr,
6462                                           int *skipped)
6463 {
6464         struct r5conf *conf = mddev->private;
6465         struct stripe_head *sh;
6466         sector_t max_sector = mddev->dev_sectors;
6467         sector_t sync_blocks;
6468         int still_degraded = 0;
6469         int i;
6470
6471         if (sector_nr >= max_sector) {
6472                 /* just being told to finish up .. nothing much to do */
6473
6474                 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
6475                         end_reshape(conf);
6476                         return 0;
6477                 }
6478
6479                 if (mddev->curr_resync < max_sector) /* aborted */
6480                         md_bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
6481                                            &sync_blocks, 1);
6482                 else /* completed sync */
6483                         conf->fullsync = 0;
6484                 md_bitmap_close_sync(mddev->bitmap);
6485
6486                 return 0;
6487         }
6488
6489         /* Allow raid5_quiesce to complete */
6490         wait_event(conf->wait_for_overlap, conf->quiesce != 2);
6491
6492         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6493                 return reshape_request(mddev, sector_nr, skipped);
6494
6495         /* No need to check resync_max as we never do more than one
6496          * stripe, and as resync_max will always be on a chunk boundary,
6497          * if the check in md_do_sync didn't fire, there is no chance
6498          * of overstepping resync_max here
6499          */
6500
6501         /* if there is too many failed drives and we are trying
6502          * to resync, then assert that we are finished, because there is
6503          * nothing we can do.
6504          */
6505         if (mddev->degraded >= conf->max_degraded &&
6506             test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
6507                 sector_t rv = mddev->dev_sectors - sector_nr;
6508                 *skipped = 1;
6509                 return rv;
6510         }
6511         if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
6512             !conf->fullsync &&
6513             !md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
6514             sync_blocks >= RAID5_STRIPE_SECTORS(conf)) {
6515                 /* we can skip this block, and probably more */
6516                 do_div(sync_blocks, RAID5_STRIPE_SECTORS(conf));
6517                 *skipped = 1;
6518                 /* keep things rounded to whole stripes */
6519                 return sync_blocks * RAID5_STRIPE_SECTORS(conf);
6520         }
6521
6522         md_bitmap_cond_end_sync(mddev->bitmap, sector_nr, false);
6523
6524         sh = raid5_get_active_stripe(conf, NULL, sector_nr,
6525                                      R5_GAS_NOBLOCK);
6526         if (sh == NULL) {
6527                 sh = raid5_get_active_stripe(conf, NULL, sector_nr, 0);
6528                 /* make sure we don't swamp the stripe cache if someone else
6529                  * is trying to get access
6530                  */
6531                 schedule_timeout_uninterruptible(1);
6532         }
6533         /* Need to check if array will still be degraded after recovery/resync
6534          * Note in case of > 1 drive failures it's possible we're rebuilding
6535          * one drive while leaving another faulty drive in array.
6536          */
6537         for (i = 0; i < conf->raid_disks; i++) {
6538                 struct md_rdev *rdev = conf->disks[i].rdev;
6539
6540                 if (rdev == NULL || test_bit(Faulty, &rdev->flags))
6541                         still_degraded = 1;
6542         }
6543
6544         md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
6545
6546         set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
6547         set_bit(STRIPE_HANDLE, &sh->state);
6548
6549         raid5_release_stripe(sh);
6550
6551         return RAID5_STRIPE_SECTORS(conf);
6552 }
6553
6554 static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio,
6555                                unsigned int offset)
6556 {
6557         /* We may not be able to submit a whole bio at once as there
6558          * may not be enough stripe_heads available.
6559          * We cannot pre-allocate enough stripe_heads as we may need
6560          * more than exist in the cache (if we allow ever large chunks).
6561          * So we do one stripe head at a time and record in
6562          * ->bi_hw_segments how many have been done.
6563          *
6564          * We *know* that this entire raid_bio is in one chunk, so
6565          * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
6566          */
6567         struct stripe_head *sh;
6568         int dd_idx;
6569         sector_t sector, logical_sector, last_sector;
6570         int scnt = 0;
6571         int handled = 0;
6572
6573         logical_sector = raid_bio->bi_iter.bi_sector &
6574                 ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
6575         sector = raid5_compute_sector(conf, logical_sector,
6576                                       0, &dd_idx, NULL);
6577         last_sector = bio_end_sector(raid_bio);
6578
6579         for (; logical_sector < last_sector;
6580              logical_sector += RAID5_STRIPE_SECTORS(conf),
6581                      sector += RAID5_STRIPE_SECTORS(conf),
6582                      scnt++) {
6583
6584                 if (scnt < offset)
6585                         /* already done this stripe */
6586                         continue;
6587
6588                 sh = raid5_get_active_stripe(conf, NULL, sector,
6589                                 R5_GAS_NOBLOCK | R5_GAS_NOQUIESCE);
6590                 if (!sh) {
6591                         /* failed to get a stripe - must wait */
6592                         conf->retry_read_aligned = raid_bio;
6593                         conf->retry_read_offset = scnt;
6594                         return handled;
6595                 }
6596
6597                 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0, 0)) {
6598                         raid5_release_stripe(sh);
6599                         conf->retry_read_aligned = raid_bio;
6600                         conf->retry_read_offset = scnt;
6601                         return handled;
6602                 }
6603
6604                 set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
6605                 handle_stripe(sh);
6606                 raid5_release_stripe(sh);
6607                 handled++;
6608         }
6609
6610         bio_endio(raid_bio);
6611
6612         if (atomic_dec_and_test(&conf->active_aligned_reads))
6613                 wake_up(&conf->wait_for_quiescent);
6614         return handled;
6615 }
6616
6617 static int handle_active_stripes(struct r5conf *conf, int group,
6618                                  struct r5worker *worker,
6619                                  struct list_head *temp_inactive_list)
6620                 __must_hold(&conf->device_lock)
6621 {
6622         struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
6623         int i, batch_size = 0, hash;
6624         bool release_inactive = false;
6625
6626         while (batch_size < MAX_STRIPE_BATCH &&
6627                         (sh = __get_priority_stripe(conf, group)) != NULL)
6628                 batch[batch_size++] = sh;
6629
6630         if (batch_size == 0) {
6631                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6632                         if (!list_empty(temp_inactive_list + i))
6633                                 break;
6634                 if (i == NR_STRIPE_HASH_LOCKS) {
6635                         spin_unlock_irq(&conf->device_lock);
6636                         log_flush_stripe_to_raid(conf);
6637                         spin_lock_irq(&conf->device_lock);
6638                         return batch_size;
6639                 }
6640                 release_inactive = true;
6641         }
6642         spin_unlock_irq(&conf->device_lock);
6643
6644         release_inactive_stripe_list(conf, temp_inactive_list,
6645                                      NR_STRIPE_HASH_LOCKS);
6646
6647         r5l_flush_stripe_to_raid(conf->log);
6648         if (release_inactive) {
6649                 spin_lock_irq(&conf->device_lock);
6650                 return 0;
6651         }
6652
6653         for (i = 0; i < batch_size; i++)
6654                 handle_stripe(batch[i]);
6655         log_write_stripe_run(conf);
6656
6657         cond_resched();
6658
6659         spin_lock_irq(&conf->device_lock);
6660         for (i = 0; i < batch_size; i++) {
6661                 hash = batch[i]->hash_lock_index;
6662                 __release_stripe(conf, batch[i], &temp_inactive_list[hash]);
6663         }
6664         return batch_size;
6665 }
6666
6667 static void raid5_do_work(struct work_struct *work)
6668 {
6669         struct r5worker *worker = container_of(work, struct r5worker, work);
6670         struct r5worker_group *group = worker->group;
6671         struct r5conf *conf = group->conf;
6672         struct mddev *mddev = conf->mddev;
6673         int group_id = group - conf->worker_groups;
6674         int handled;
6675         struct blk_plug plug;
6676
6677         pr_debug("+++ raid5worker active\n");
6678
6679         blk_start_plug(&plug);
6680         handled = 0;
6681         spin_lock_irq(&conf->device_lock);
6682         while (1) {
6683                 int batch_size, released;
6684
6685                 released = release_stripe_list(conf, worker->temp_inactive_list);
6686
6687                 batch_size = handle_active_stripes(conf, group_id, worker,
6688                                                    worker->temp_inactive_list);
6689                 worker->working = false;
6690                 if (!batch_size && !released)
6691                         break;
6692                 handled += batch_size;
6693                 wait_event_lock_irq(mddev->sb_wait,
6694                         !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
6695                         conf->device_lock);
6696         }
6697         pr_debug("%d stripes handled\n", handled);
6698
6699         spin_unlock_irq(&conf->device_lock);
6700
6701         flush_deferred_bios(conf);
6702
6703         r5l_flush_stripe_to_raid(conf->log);
6704
6705         async_tx_issue_pending_all();
6706         blk_finish_plug(&plug);
6707
6708         pr_debug("--- raid5worker inactive\n");
6709 }
6710
6711 /*
6712  * This is our raid5 kernel thread.
6713  *
6714  * We scan the hash table for stripes which can be handled now.
6715  * During the scan, completed stripes are saved for us by the interrupt
6716  * handler, so that they will not have to wait for our next wakeup.
6717  */
6718 static void raid5d(struct md_thread *thread)
6719 {
6720         struct mddev *mddev = thread->mddev;
6721         struct r5conf *conf = mddev->private;
6722         int handled;
6723         struct blk_plug plug;
6724
6725         pr_debug("+++ raid5d active\n");
6726
6727         md_check_recovery(mddev);
6728
6729         blk_start_plug(&plug);
6730         handled = 0;
6731         spin_lock_irq(&conf->device_lock);
6732         while (1) {
6733                 struct bio *bio;
6734                 int batch_size, released;
6735                 unsigned int offset;
6736
6737                 released = release_stripe_list(conf, conf->temp_inactive_list);
6738                 if (released)
6739                         clear_bit(R5_DID_ALLOC, &conf->cache_state);
6740
6741                 if (
6742                     !list_empty(&conf->bitmap_list)) {
6743                         /* Now is a good time to flush some bitmap updates */
6744                         conf->seq_flush++;
6745                         spin_unlock_irq(&conf->device_lock);
6746                         md_bitmap_unplug(mddev->bitmap);
6747                         spin_lock_irq(&conf->device_lock);
6748                         conf->seq_write = conf->seq_flush;
6749                         activate_bit_delay(conf, conf->temp_inactive_list);
6750                 }
6751                 raid5_activate_delayed(conf);
6752
6753                 while ((bio = remove_bio_from_retry(conf, &offset))) {
6754                         int ok;
6755                         spin_unlock_irq(&conf->device_lock);
6756                         ok = retry_aligned_read(conf, bio, offset);
6757                         spin_lock_irq(&conf->device_lock);
6758                         if (!ok)
6759                                 break;
6760                         handled++;
6761                 }
6762
6763                 batch_size = handle_active_stripes(conf, ANY_GROUP, NULL,
6764                                                    conf->temp_inactive_list);
6765                 if (!batch_size && !released)
6766                         break;
6767                 handled += batch_size;
6768
6769                 if (mddev->sb_flags & ~(1 << MD_SB_CHANGE_PENDING)) {
6770                         spin_unlock_irq(&conf->device_lock);
6771                         md_check_recovery(mddev);
6772                         spin_lock_irq(&conf->device_lock);
6773
6774                         /*
6775                          * Waiting on MD_SB_CHANGE_PENDING below may deadlock
6776                          * seeing md_check_recovery() is needed to clear
6777                          * the flag when using mdmon.
6778                          */
6779                         continue;
6780                 }
6781
6782                 wait_event_lock_irq(mddev->sb_wait,
6783                         !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
6784                         conf->device_lock);
6785         }
6786         pr_debug("%d stripes handled\n", handled);
6787
6788         spin_unlock_irq(&conf->device_lock);
6789         if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state) &&
6790             mutex_trylock(&conf->cache_size_mutex)) {
6791                 grow_one_stripe(conf, __GFP_NOWARN);
6792                 /* Set flag even if allocation failed.  This helps
6793                  * slow down allocation requests when mem is short
6794                  */
6795                 set_bit(R5_DID_ALLOC, &conf->cache_state);
6796                 mutex_unlock(&conf->cache_size_mutex);
6797         }
6798
6799         flush_deferred_bios(conf);
6800
6801         r5l_flush_stripe_to_raid(conf->log);
6802
6803         async_tx_issue_pending_all();
6804         blk_finish_plug(&plug);
6805
6806         pr_debug("--- raid5d inactive\n");
6807 }
6808
6809 static ssize_t
6810 raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
6811 {
6812         struct r5conf *conf;
6813         int ret = 0;
6814         spin_lock(&mddev->lock);
6815         conf = mddev->private;
6816         if (conf)
6817                 ret = sprintf(page, "%d\n", conf->min_nr_stripes);
6818         spin_unlock(&mddev->lock);
6819         return ret;
6820 }
6821
6822 int
6823 raid5_set_cache_size(struct mddev *mddev, int size)
6824 {
6825         int result = 0;
6826         struct r5conf *conf = mddev->private;
6827
6828         if (size <= 16 || size > 32768)
6829                 return -EINVAL;
6830
6831         WRITE_ONCE(conf->min_nr_stripes, size);
6832         mutex_lock(&conf->cache_size_mutex);
6833         while (size < conf->max_nr_stripes &&
6834                drop_one_stripe(conf))
6835                 ;
6836         mutex_unlock(&conf->cache_size_mutex);
6837
6838         md_allow_write(mddev);
6839
6840         mutex_lock(&conf->cache_size_mutex);
6841         while (size > conf->max_nr_stripes)
6842                 if (!grow_one_stripe(conf, GFP_KERNEL)) {
6843                         WRITE_ONCE(conf->min_nr_stripes, conf->max_nr_stripes);
6844                         result = -ENOMEM;
6845                         break;
6846                 }
6847         mutex_unlock(&conf->cache_size_mutex);
6848
6849         return result;
6850 }
6851 EXPORT_SYMBOL(raid5_set_cache_size);
6852
6853 static ssize_t
6854 raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
6855 {
6856         struct r5conf *conf;
6857         unsigned long new;
6858         int err;
6859
6860         if (len >= PAGE_SIZE)
6861                 return -EINVAL;
6862         if (kstrtoul(page, 10, &new))
6863                 return -EINVAL;
6864         err = mddev_lock(mddev);
6865         if (err)
6866                 return err;
6867         conf = mddev->private;
6868         if (!conf)
6869                 err = -ENODEV;
6870         else
6871                 err = raid5_set_cache_size(mddev, new);
6872         mddev_unlock(mddev);
6873
6874         return err ?: len;
6875 }
6876
6877 static struct md_sysfs_entry
6878 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
6879                                 raid5_show_stripe_cache_size,
6880                                 raid5_store_stripe_cache_size);
6881
6882 static ssize_t
6883 raid5_show_rmw_level(struct mddev  *mddev, char *page)
6884 {
6885         struct r5conf *conf = mddev->private;
6886         if (conf)
6887                 return sprintf(page, "%d\n", conf->rmw_level);
6888         else
6889                 return 0;
6890 }
6891
6892 static ssize_t
6893 raid5_store_rmw_level(struct mddev  *mddev, const char *page, size_t len)
6894 {
6895         struct r5conf *conf = mddev->private;
6896         unsigned long new;
6897
6898         if (!conf)
6899                 return -ENODEV;
6900
6901         if (len >= PAGE_SIZE)
6902                 return -EINVAL;
6903
6904         if (kstrtoul(page, 10, &new))
6905                 return -EINVAL;
6906
6907         if (new != PARITY_DISABLE_RMW && !raid6_call.xor_syndrome)
6908                 return -EINVAL;
6909
6910         if (new != PARITY_DISABLE_RMW &&
6911             new != PARITY_ENABLE_RMW &&
6912             new != PARITY_PREFER_RMW)
6913                 return -EINVAL;
6914
6915         conf->rmw_level = new;
6916         return len;
6917 }
6918
6919 static struct md_sysfs_entry
6920 raid5_rmw_level = __ATTR(rmw_level, S_IRUGO | S_IWUSR,
6921                          raid5_show_rmw_level,
6922                          raid5_store_rmw_level);
6923
6924 static ssize_t
6925 raid5_show_stripe_size(struct mddev  *mddev, char *page)
6926 {
6927         struct r5conf *conf;
6928         int ret = 0;
6929
6930         spin_lock(&mddev->lock);
6931         conf = mddev->private;
6932         if (conf)
6933                 ret = sprintf(page, "%lu\n", RAID5_STRIPE_SIZE(conf));
6934         spin_unlock(&mddev->lock);
6935         return ret;
6936 }
6937
6938 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
6939 static ssize_t
6940 raid5_store_stripe_size(struct mddev  *mddev, const char *page, size_t len)
6941 {
6942         struct r5conf *conf;
6943         unsigned long new;
6944         int err;
6945         int size;
6946
6947         if (len >= PAGE_SIZE)
6948                 return -EINVAL;
6949         if (kstrtoul(page, 10, &new))
6950                 return -EINVAL;
6951
6952         /*
6953          * The value should not be bigger than PAGE_SIZE. It requires to
6954          * be multiple of DEFAULT_STRIPE_SIZE and the value should be power
6955          * of two.
6956          */
6957         if (new % DEFAULT_STRIPE_SIZE != 0 ||
6958                         new > PAGE_SIZE || new == 0 ||
6959                         new != roundup_pow_of_two(new))
6960                 return -EINVAL;
6961
6962         err = mddev_suspend_and_lock(mddev);
6963         if (err)
6964                 return err;
6965
6966         conf = mddev->private;
6967         if (!conf) {
6968                 err = -ENODEV;
6969                 goto out_unlock;
6970         }
6971
6972         if (new == conf->stripe_size)
6973                 goto out_unlock;
6974
6975         pr_debug("md/raid: change stripe_size from %lu to %lu\n",
6976                         conf->stripe_size, new);
6977
6978         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
6979             mddev->reshape_position != MaxSector || mddev->sysfs_active) {
6980                 err = -EBUSY;
6981                 goto out_unlock;
6982         }
6983
6984         mutex_lock(&conf->cache_size_mutex);
6985         size = conf->max_nr_stripes;
6986
6987         shrink_stripes(conf);
6988
6989         conf->stripe_size = new;
6990         conf->stripe_shift = ilog2(new) - 9;
6991         conf->stripe_sectors = new >> 9;
6992         if (grow_stripes(conf, size)) {
6993                 pr_warn("md/raid:%s: couldn't allocate buffers\n",
6994                                 mdname(mddev));
6995                 err = -ENOMEM;
6996         }
6997         mutex_unlock(&conf->cache_size_mutex);
6998
6999 out_unlock:
7000         mddev_unlock_and_resume(mddev);
7001         return err ?: len;
7002 }
7003
7004 static struct md_sysfs_entry
7005 raid5_stripe_size = __ATTR(stripe_size, 0644,
7006                          raid5_show_stripe_size,
7007                          raid5_store_stripe_size);
7008 #else
7009 static struct md_sysfs_entry
7010 raid5_stripe_size = __ATTR(stripe_size, 0444,
7011                          raid5_show_stripe_size,
7012                          NULL);
7013 #endif
7014
7015 static ssize_t
7016 raid5_show_preread_threshold(struct mddev *mddev, char *page)
7017 {
7018         struct r5conf *conf;
7019         int ret = 0;
7020         spin_lock(&mddev->lock);
7021         conf = mddev->private;
7022         if (conf)
7023                 ret = sprintf(page, "%d\n", conf->bypass_threshold);
7024         spin_unlock(&mddev->lock);
7025         return ret;
7026 }
7027
7028 static ssize_t
7029 raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
7030 {
7031         struct r5conf *conf;
7032         unsigned long new;
7033         int err;
7034
7035         if (len >= PAGE_SIZE)
7036                 return -EINVAL;
7037         if (kstrtoul(page, 10, &new))
7038                 return -EINVAL;
7039
7040         err = mddev_lock(mddev);
7041         if (err)
7042                 return err;
7043         conf = mddev->private;
7044         if (!conf)
7045                 err = -ENODEV;
7046         else if (new > conf->min_nr_stripes)
7047                 err = -EINVAL;
7048         else
7049                 conf->bypass_threshold = new;
7050         mddev_unlock(mddev);
7051         return err ?: len;
7052 }
7053
7054 static struct md_sysfs_entry
7055 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
7056                                         S_IRUGO | S_IWUSR,
7057                                         raid5_show_preread_threshold,
7058                                         raid5_store_preread_threshold);
7059
7060 static ssize_t
7061 raid5_show_skip_copy(struct mddev *mddev, char *page)
7062 {
7063         struct r5conf *conf;
7064         int ret = 0;
7065         spin_lock(&mddev->lock);
7066         conf = mddev->private;
7067         if (conf)
7068                 ret = sprintf(page, "%d\n", conf->skip_copy);
7069         spin_unlock(&mddev->lock);
7070         return ret;
7071 }
7072
7073 static ssize_t
7074 raid5_store_skip_copy(struct mddev *mddev, const char *page, size_t len)
7075 {
7076         struct r5conf *conf;
7077         unsigned long new;
7078         int err;
7079
7080         if (len >= PAGE_SIZE)
7081                 return -EINVAL;
7082         if (kstrtoul(page, 10, &new))
7083                 return -EINVAL;
7084         new = !!new;
7085
7086         err = mddev_suspend_and_lock(mddev);
7087         if (err)
7088                 return err;
7089         conf = mddev->private;
7090         if (!conf)
7091                 err = -ENODEV;
7092         else if (new != conf->skip_copy) {
7093                 struct request_queue *q = mddev->gendisk->queue;
7094
7095                 conf->skip_copy = new;
7096                 if (new)
7097                         blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES, q);
7098                 else
7099                         blk_queue_flag_clear(QUEUE_FLAG_STABLE_WRITES, q);
7100         }
7101         mddev_unlock_and_resume(mddev);
7102         return err ?: len;
7103 }
7104
7105 static struct md_sysfs_entry
7106 raid5_skip_copy = __ATTR(skip_copy, S_IRUGO | S_IWUSR,
7107                                         raid5_show_skip_copy,
7108                                         raid5_store_skip_copy);
7109
7110 static ssize_t
7111 stripe_cache_active_show(struct mddev *mddev, char *page)
7112 {
7113         struct r5conf *conf = mddev->private;
7114         if (conf)
7115                 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
7116         else
7117                 return 0;
7118 }
7119
7120 static struct md_sysfs_entry
7121 raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
7122
7123 static ssize_t
7124 raid5_show_group_thread_cnt(struct mddev *mddev, char *page)
7125 {
7126         struct r5conf *conf;
7127         int ret = 0;
7128         spin_lock(&mddev->lock);
7129         conf = mddev->private;
7130         if (conf)
7131                 ret = sprintf(page, "%d\n", conf->worker_cnt_per_group);
7132         spin_unlock(&mddev->lock);
7133         return ret;
7134 }
7135
7136 static int alloc_thread_groups(struct r5conf *conf, int cnt,
7137                                int *group_cnt,
7138                                struct r5worker_group **worker_groups);
7139 static ssize_t
7140 raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
7141 {
7142         struct r5conf *conf;
7143         unsigned int new;
7144         int err;
7145         struct r5worker_group *new_groups, *old_groups;
7146         int group_cnt;
7147
7148         if (len >= PAGE_SIZE)
7149                 return -EINVAL;
7150         if (kstrtouint(page, 10, &new))
7151                 return -EINVAL;
7152         /* 8192 should be big enough */
7153         if (new > 8192)
7154                 return -EINVAL;
7155
7156         err = mddev_suspend_and_lock(mddev);
7157         if (err)
7158                 return err;
7159         conf = mddev->private;
7160         if (!conf)
7161                 err = -ENODEV;
7162         else if (new != conf->worker_cnt_per_group) {
7163                 old_groups = conf->worker_groups;
7164                 if (old_groups)
7165                         flush_workqueue(raid5_wq);
7166
7167                 err = alloc_thread_groups(conf, new, &group_cnt, &new_groups);
7168                 if (!err) {
7169                         spin_lock_irq(&conf->device_lock);
7170                         conf->group_cnt = group_cnt;
7171                         conf->worker_cnt_per_group = new;
7172                         conf->worker_groups = new_groups;
7173                         spin_unlock_irq(&conf->device_lock);
7174
7175                         if (old_groups)
7176                                 kfree(old_groups[0].workers);
7177                         kfree(old_groups);
7178                 }
7179         }
7180         mddev_unlock_and_resume(mddev);
7181
7182         return err ?: len;
7183 }
7184
7185 static struct md_sysfs_entry
7186 raid5_group_thread_cnt = __ATTR(group_thread_cnt, S_IRUGO | S_IWUSR,
7187                                 raid5_show_group_thread_cnt,
7188                                 raid5_store_group_thread_cnt);
7189
7190 static struct attribute *raid5_attrs[] =  {
7191         &raid5_stripecache_size.attr,
7192         &raid5_stripecache_active.attr,
7193         &raid5_preread_bypass_threshold.attr,
7194         &raid5_group_thread_cnt.attr,
7195         &raid5_skip_copy.attr,
7196         &raid5_rmw_level.attr,
7197         &raid5_stripe_size.attr,
7198         &r5c_journal_mode.attr,
7199         &ppl_write_hint.attr,
7200         NULL,
7201 };
7202 static const struct attribute_group raid5_attrs_group = {
7203         .name = NULL,
7204         .attrs = raid5_attrs,
7205 };
7206
7207 static int alloc_thread_groups(struct r5conf *conf, int cnt, int *group_cnt,
7208                                struct r5worker_group **worker_groups)
7209 {
7210         int i, j, k;
7211         ssize_t size;
7212         struct r5worker *workers;
7213
7214         if (cnt == 0) {
7215                 *group_cnt = 0;
7216                 *worker_groups = NULL;
7217                 return 0;
7218         }
7219         *group_cnt = num_possible_nodes();
7220         size = sizeof(struct r5worker) * cnt;
7221         workers = kcalloc(size, *group_cnt, GFP_NOIO);
7222         *worker_groups = kcalloc(*group_cnt, sizeof(struct r5worker_group),
7223                                  GFP_NOIO);
7224         if (!*worker_groups || !workers) {
7225                 kfree(workers);
7226                 kfree(*worker_groups);
7227                 return -ENOMEM;
7228         }
7229
7230         for (i = 0; i < *group_cnt; i++) {
7231                 struct r5worker_group *group;
7232
7233                 group = &(*worker_groups)[i];
7234                 INIT_LIST_HEAD(&group->handle_list);
7235                 INIT_LIST_HEAD(&group->loprio_list);
7236                 group->conf = conf;
7237                 group->workers = workers + i * cnt;
7238
7239                 for (j = 0; j < cnt; j++) {
7240                         struct r5worker *worker = group->workers + j;
7241                         worker->group = group;
7242                         INIT_WORK(&worker->work, raid5_do_work);
7243
7244                         for (k = 0; k < NR_STRIPE_HASH_LOCKS; k++)
7245                                 INIT_LIST_HEAD(worker->temp_inactive_list + k);
7246                 }
7247         }
7248
7249         return 0;
7250 }
7251
7252 static void free_thread_groups(struct r5conf *conf)
7253 {
7254         if (conf->worker_groups)
7255                 kfree(conf->worker_groups[0].workers);
7256         kfree(conf->worker_groups);
7257         conf->worker_groups = NULL;
7258 }
7259
7260 static sector_t
7261 raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
7262 {
7263         struct r5conf *conf = mddev->private;
7264
7265         if (!sectors)
7266                 sectors = mddev->dev_sectors;
7267         if (!raid_disks)
7268                 /* size is defined by the smallest of previous and new size */
7269                 raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
7270
7271         sectors &= ~((sector_t)conf->chunk_sectors - 1);
7272         sectors &= ~((sector_t)conf->prev_chunk_sectors - 1);
7273         return sectors * (raid_disks - conf->max_degraded);
7274 }
7275
7276 static void free_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
7277 {
7278         safe_put_page(percpu->spare_page);
7279         percpu->spare_page = NULL;
7280         kvfree(percpu->scribble);
7281         percpu->scribble = NULL;
7282 }
7283
7284 static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
7285 {
7286         if (conf->level == 6 && !percpu->spare_page) {
7287                 percpu->spare_page = alloc_page(GFP_KERNEL);
7288                 if (!percpu->spare_page)
7289                         return -ENOMEM;
7290         }
7291
7292         if (scribble_alloc(percpu,
7293                            max(conf->raid_disks,
7294                                conf->previous_raid_disks),
7295                            max(conf->chunk_sectors,
7296                                conf->prev_chunk_sectors)
7297                            / RAID5_STRIPE_SECTORS(conf))) {
7298                 free_scratch_buffer(conf, percpu);
7299                 return -ENOMEM;
7300         }
7301
7302         local_lock_init(&percpu->lock);
7303         return 0;
7304 }
7305
7306 static int raid456_cpu_dead(unsigned int cpu, struct hlist_node *node)
7307 {
7308         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
7309
7310         free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));
7311         return 0;
7312 }
7313
7314 static void raid5_free_percpu(struct r5conf *conf)
7315 {
7316         if (!conf->percpu)
7317                 return;
7318
7319         cpuhp_state_remove_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
7320         free_percpu(conf->percpu);
7321 }
7322
7323 static void free_conf(struct r5conf *conf)
7324 {
7325         int i;
7326
7327         log_exit(conf);
7328
7329         shrinker_free(conf->shrinker);
7330         free_thread_groups(conf);
7331         shrink_stripes(conf);
7332         raid5_free_percpu(conf);
7333         for (i = 0; i < conf->pool_size; i++)
7334                 if (conf->disks[i].extra_page)
7335                         put_page(conf->disks[i].extra_page);
7336         kfree(conf->disks);
7337         bioset_exit(&conf->bio_split);
7338         kfree(conf->stripe_hashtbl);
7339         kfree(conf->pending_data);
7340         kfree(conf);
7341 }
7342
7343 static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
7344 {
7345         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
7346         struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);
7347
7348         if (alloc_scratch_buffer(conf, percpu)) {
7349                 pr_warn("%s: failed memory allocation for cpu%u\n",
7350                         __func__, cpu);
7351                 return -ENOMEM;
7352         }
7353         return 0;
7354 }
7355
7356 static int raid5_alloc_percpu(struct r5conf *conf)
7357 {
7358         int err = 0;
7359
7360         conf->percpu = alloc_percpu(struct raid5_percpu);
7361         if (!conf->percpu)
7362                 return -ENOMEM;
7363
7364         err = cpuhp_state_add_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
7365         if (!err) {
7366                 conf->scribble_disks = max(conf->raid_disks,
7367                         conf->previous_raid_disks);
7368                 conf->scribble_sectors = max(conf->chunk_sectors,
7369                         conf->prev_chunk_sectors);
7370         }
7371         return err;
7372 }
7373
7374 static unsigned long raid5_cache_scan(struct shrinker *shrink,
7375                                       struct shrink_control *sc)
7376 {
7377         struct r5conf *conf = shrink->private_data;
7378         unsigned long ret = SHRINK_STOP;
7379
7380         if (mutex_trylock(&conf->cache_size_mutex)) {
7381                 ret= 0;
7382                 while (ret < sc->nr_to_scan &&
7383                        conf->max_nr_stripes > conf->min_nr_stripes) {
7384                         if (drop_one_stripe(conf) == 0) {
7385                                 ret = SHRINK_STOP;
7386                                 break;
7387                         }
7388                         ret++;
7389                 }
7390                 mutex_unlock(&conf->cache_size_mutex);
7391         }
7392         return ret;
7393 }
7394
7395 static unsigned long raid5_cache_count(struct shrinker *shrink,
7396                                        struct shrink_control *sc)
7397 {
7398         struct r5conf *conf = shrink->private_data;
7399         int max_stripes = READ_ONCE(conf->max_nr_stripes);
7400         int min_stripes = READ_ONCE(conf->min_nr_stripes);
7401
7402         if (max_stripes < min_stripes)
7403                 /* unlikely, but not impossible */
7404                 return 0;
7405         return max_stripes - min_stripes;
7406 }
7407
7408 static struct r5conf *setup_conf(struct mddev *mddev)
7409 {
7410         struct r5conf *conf;
7411         int raid_disk, memory, max_disks;
7412         struct md_rdev *rdev;
7413         struct disk_info *disk;
7414         char pers_name[6];
7415         int i;
7416         int group_cnt;
7417         struct r5worker_group *new_group;
7418         int ret = -ENOMEM;
7419
7420         if (mddev->new_level != 5
7421             && mddev->new_level != 4
7422             && mddev->new_level != 6) {
7423                 pr_warn("md/raid:%s: raid level not set to 4/5/6 (%d)\n",
7424                         mdname(mddev), mddev->new_level);
7425                 return ERR_PTR(-EIO);
7426         }
7427         if ((mddev->new_level == 5
7428              && !algorithm_valid_raid5(mddev->new_layout)) ||
7429             (mddev->new_level == 6
7430              && !algorithm_valid_raid6(mddev->new_layout))) {
7431                 pr_warn("md/raid:%s: layout %d not supported\n",
7432                         mdname(mddev), mddev->new_layout);
7433                 return ERR_PTR(-EIO);
7434         }
7435         if (mddev->new_level == 6 && mddev->raid_disks < 4) {
7436                 pr_warn("md/raid:%s: not enough configured devices (%d, minimum 4)\n",
7437                         mdname(mddev), mddev->raid_disks);
7438                 return ERR_PTR(-EINVAL);
7439         }
7440
7441         if (!mddev->new_chunk_sectors ||
7442             (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
7443             !is_power_of_2(mddev->new_chunk_sectors)) {
7444                 pr_warn("md/raid:%s: invalid chunk size %d\n",
7445                         mdname(mddev), mddev->new_chunk_sectors << 9);
7446                 return ERR_PTR(-EINVAL);
7447         }
7448
7449         conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
7450         if (conf == NULL)
7451                 goto abort;
7452
7453 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
7454         conf->stripe_size = DEFAULT_STRIPE_SIZE;
7455         conf->stripe_shift = ilog2(DEFAULT_STRIPE_SIZE) - 9;
7456         conf->stripe_sectors = DEFAULT_STRIPE_SIZE >> 9;
7457 #endif
7458         INIT_LIST_HEAD(&conf->free_list);
7459         INIT_LIST_HEAD(&conf->pending_list);
7460         conf->pending_data = kcalloc(PENDING_IO_MAX,
7461                                      sizeof(struct r5pending_data),
7462                                      GFP_KERNEL);
7463         if (!conf->pending_data)
7464                 goto abort;
7465         for (i = 0; i < PENDING_IO_MAX; i++)
7466                 list_add(&conf->pending_data[i].sibling, &conf->free_list);
7467         /* Don't enable multi-threading by default*/
7468         if (!alloc_thread_groups(conf, 0, &group_cnt, &new_group)) {
7469                 conf->group_cnt = group_cnt;
7470                 conf->worker_cnt_per_group = 0;
7471                 conf->worker_groups = new_group;
7472         } else
7473                 goto abort;
7474         spin_lock_init(&conf->device_lock);
7475         seqcount_spinlock_init(&conf->gen_lock, &conf->device_lock);
7476         mutex_init(&conf->cache_size_mutex);
7477
7478         init_waitqueue_head(&conf->wait_for_quiescent);
7479         init_waitqueue_head(&conf->wait_for_stripe);
7480         init_waitqueue_head(&conf->wait_for_overlap);
7481         INIT_LIST_HEAD(&conf->handle_list);
7482         INIT_LIST_HEAD(&conf->loprio_list);
7483         INIT_LIST_HEAD(&conf->hold_list);
7484         INIT_LIST_HEAD(&conf->delayed_list);
7485         INIT_LIST_HEAD(&conf->bitmap_list);
7486         init_llist_head(&conf->released_stripes);
7487         atomic_set(&conf->active_stripes, 0);
7488         atomic_set(&conf->preread_active_stripes, 0);
7489         atomic_set(&conf->active_aligned_reads, 0);
7490         spin_lock_init(&conf->pending_bios_lock);
7491         conf->batch_bio_dispatch = true;
7492         rdev_for_each(rdev, mddev) {
7493                 if (test_bit(Journal, &rdev->flags))
7494                         continue;
7495                 if (bdev_nonrot(rdev->bdev)) {
7496                         conf->batch_bio_dispatch = false;
7497                         break;
7498                 }
7499         }
7500
7501         conf->bypass_threshold = BYPASS_THRESHOLD;
7502         conf->recovery_disabled = mddev->recovery_disabled - 1;
7503
7504         conf->raid_disks = mddev->raid_disks;
7505         if (mddev->reshape_position == MaxSector)
7506                 conf->previous_raid_disks = mddev->raid_disks;
7507         else
7508                 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
7509         max_disks = max(conf->raid_disks, conf->previous_raid_disks);
7510
7511         conf->disks = kcalloc(max_disks, sizeof(struct disk_info),
7512                               GFP_KERNEL);
7513
7514         if (!conf->disks)
7515                 goto abort;
7516
7517         for (i = 0; i < max_disks; i++) {
7518                 conf->disks[i].extra_page = alloc_page(GFP_KERNEL);
7519                 if (!conf->disks[i].extra_page)
7520                         goto abort;
7521         }
7522
7523         ret = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
7524         if (ret)
7525                 goto abort;
7526         conf->mddev = mddev;
7527
7528         ret = -ENOMEM;
7529         conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL);
7530         if (!conf->stripe_hashtbl)
7531                 goto abort;
7532
7533         /* We init hash_locks[0] separately to that it can be used
7534          * as the reference lock in the spin_lock_nest_lock() call
7535          * in lock_all_device_hash_locks_irq in order to convince
7536          * lockdep that we know what we are doing.
7537          */
7538         spin_lock_init(conf->hash_locks);
7539         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
7540                 spin_lock_init(conf->hash_locks + i);
7541
7542         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
7543                 INIT_LIST_HEAD(conf->inactive_list + i);
7544
7545         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
7546                 INIT_LIST_HEAD(conf->temp_inactive_list + i);
7547
7548         atomic_set(&conf->r5c_cached_full_stripes, 0);
7549         INIT_LIST_HEAD(&conf->r5c_full_stripe_list);
7550         atomic_set(&conf->r5c_cached_partial_stripes, 0);
7551         INIT_LIST_HEAD(&conf->r5c_partial_stripe_list);
7552         atomic_set(&conf->r5c_flushing_full_stripes, 0);
7553         atomic_set(&conf->r5c_flushing_partial_stripes, 0);
7554
7555         conf->level = mddev->new_level;
7556         conf->chunk_sectors = mddev->new_chunk_sectors;
7557         ret = raid5_alloc_percpu(conf);
7558         if (ret)
7559                 goto abort;
7560
7561         pr_debug("raid456: run(%s) called.\n", mdname(mddev));
7562
7563         ret = -EIO;
7564         rdev_for_each(rdev, mddev) {
7565                 raid_disk = rdev->raid_disk;
7566                 if (raid_disk >= max_disks
7567                     || raid_disk < 0 || test_bit(Journal, &rdev->flags))
7568                         continue;
7569                 disk = conf->disks + raid_disk;
7570
7571                 if (test_bit(Replacement, &rdev->flags)) {
7572                         if (disk->replacement)
7573                                 goto abort;
7574                         RCU_INIT_POINTER(disk->replacement, rdev);
7575                 } else {
7576                         if (disk->rdev)
7577                                 goto abort;
7578                         RCU_INIT_POINTER(disk->rdev, rdev);
7579                 }
7580
7581                 if (test_bit(In_sync, &rdev->flags)) {
7582                         pr_info("md/raid:%s: device %pg operational as raid disk %d\n",
7583                                 mdname(mddev), rdev->bdev, raid_disk);
7584                 } else if (rdev->saved_raid_disk != raid_disk)
7585                         /* Cannot rely on bitmap to complete recovery */
7586                         conf->fullsync = 1;
7587         }
7588
7589         conf->level = mddev->new_level;
7590         if (conf->level == 6) {
7591                 conf->max_degraded = 2;
7592                 if (raid6_call.xor_syndrome)
7593                         conf->rmw_level = PARITY_ENABLE_RMW;
7594                 else
7595                         conf->rmw_level = PARITY_DISABLE_RMW;
7596         } else {
7597                 conf->max_degraded = 1;
7598                 conf->rmw_level = PARITY_ENABLE_RMW;
7599         }
7600         conf->algorithm = mddev->new_layout;
7601         conf->reshape_progress = mddev->reshape_position;
7602         if (conf->reshape_progress != MaxSector) {
7603                 conf->prev_chunk_sectors = mddev->chunk_sectors;
7604                 conf->prev_algo = mddev->layout;
7605         } else {
7606                 conf->prev_chunk_sectors = conf->chunk_sectors;
7607                 conf->prev_algo = conf->algorithm;
7608         }
7609
7610         conf->min_nr_stripes = NR_STRIPES;
7611         if (mddev->reshape_position != MaxSector) {
7612                 int stripes = max_t(int,
7613                         ((mddev->chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4,
7614                         ((mddev->new_chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4);
7615                 conf->min_nr_stripes = max(NR_STRIPES, stripes);
7616                 if (conf->min_nr_stripes != NR_STRIPES)
7617                         pr_info("md/raid:%s: force stripe size %d for reshape\n",
7618                                 mdname(mddev), conf->min_nr_stripes);
7619         }
7620         memory = conf->min_nr_stripes * (sizeof(struct stripe_head) +
7621                  max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
7622         atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS);
7623         if (grow_stripes(conf, conf->min_nr_stripes)) {
7624                 pr_warn("md/raid:%s: couldn't allocate %dkB for buffers\n",
7625                         mdname(mddev), memory);
7626                 ret = -ENOMEM;
7627                 goto abort;
7628         } else
7629                 pr_debug("md/raid:%s: allocated %dkB\n", mdname(mddev), memory);
7630         /*
7631          * Losing a stripe head costs more than the time to refill it,
7632          * it reduces the queue depth and so can hurt throughput.
7633          * So set it rather large, scaled by number of devices.
7634          */
7635         conf->shrinker = shrinker_alloc(0, "md-raid5:%s", mdname(mddev));
7636         if (!conf->shrinker) {
7637                 ret = -ENOMEM;
7638                 pr_warn("md/raid:%s: couldn't allocate shrinker.\n",
7639                         mdname(mddev));
7640                 goto abort;
7641         }
7642
7643         conf->shrinker->seeks = DEFAULT_SEEKS * conf->raid_disks * 4;
7644         conf->shrinker->scan_objects = raid5_cache_scan;
7645         conf->shrinker->count_objects = raid5_cache_count;
7646         conf->shrinker->batch = 128;
7647         conf->shrinker->private_data = conf;
7648
7649         shrinker_register(conf->shrinker);
7650
7651         sprintf(pers_name, "raid%d", mddev->new_level);
7652         rcu_assign_pointer(conf->thread,
7653                            md_register_thread(raid5d, mddev, pers_name));
7654         if (!conf->thread) {
7655                 pr_warn("md/raid:%s: couldn't allocate thread.\n",
7656                         mdname(mddev));
7657                 ret = -ENOMEM;
7658                 goto abort;
7659         }
7660
7661         return conf;
7662
7663  abort:
7664         if (conf)
7665                 free_conf(conf);
7666         return ERR_PTR(ret);
7667 }
7668
7669 static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
7670 {
7671         switch (algo) {
7672         case ALGORITHM_PARITY_0:
7673                 if (raid_disk < max_degraded)
7674                         return 1;
7675                 break;
7676         case ALGORITHM_PARITY_N:
7677                 if (raid_disk >= raid_disks - max_degraded)
7678                         return 1;
7679                 break;
7680         case ALGORITHM_PARITY_0_6:
7681                 if (raid_disk == 0 ||
7682                     raid_disk == raid_disks - 1)
7683                         return 1;
7684                 break;
7685         case ALGORITHM_LEFT_ASYMMETRIC_6:
7686         case ALGORITHM_RIGHT_ASYMMETRIC_6:
7687         case ALGORITHM_LEFT_SYMMETRIC_6:
7688         case ALGORITHM_RIGHT_SYMMETRIC_6:
7689                 if (raid_disk == raid_disks - 1)
7690                         return 1;
7691         }
7692         return 0;
7693 }
7694
7695 static int raid5_set_limits(struct mddev *mddev)
7696 {
7697         struct r5conf *conf = mddev->private;
7698         struct queue_limits lim;
7699         int data_disks, stripe;
7700         struct md_rdev *rdev;
7701
7702         /*
7703          * The read-ahead size must cover two whole stripes, which is
7704          * 2 * (datadisks) * chunksize where 'n' is the number of raid devices.
7705          */
7706         data_disks = conf->previous_raid_disks - conf->max_degraded;
7707
7708         /*
7709          * We can only discard a whole stripe. It doesn't make sense to
7710          * discard data disk but write parity disk
7711          */
7712         stripe = roundup_pow_of_two(data_disks * (mddev->chunk_sectors << 9));
7713
7714         blk_set_stacking_limits(&lim);
7715         lim.io_min = mddev->chunk_sectors << 9;
7716         lim.io_opt = lim.io_min * (conf->raid_disks - conf->max_degraded);
7717         lim.raid_partial_stripes_expensive = 1;
7718         lim.discard_granularity = stripe;
7719         lim.max_write_zeroes_sectors = 0;
7720         mddev_stack_rdev_limits(mddev, &lim);
7721         rdev_for_each(rdev, mddev)
7722                 queue_limits_stack_bdev(&lim, rdev->bdev, rdev->new_data_offset,
7723                                 mddev->gendisk->disk_name);
7724
7725         /*
7726          * Zeroing is required for discard, otherwise data could be lost.
7727          *
7728          * Consider a scenario: discard a stripe (the stripe could be
7729          * inconsistent if discard_zeroes_data is 0); write one disk of the
7730          * stripe (the stripe could be inconsistent again depending on which
7731          * disks are used to calculate parity); the disk is broken; The stripe
7732          * data of this disk is lost.
7733          *
7734          * We only allow DISCARD if the sysadmin has confirmed that only safe
7735          * devices are in use by setting a module parameter.  A better idea
7736          * might be to turn DISCARD into WRITE_ZEROES requests, as that is
7737          * required to be safe.
7738          */
7739         if (!devices_handle_discard_safely ||
7740             lim.max_discard_sectors < (stripe >> 9) ||
7741             lim.discard_granularity < stripe)
7742                 lim.max_hw_discard_sectors = 0;
7743
7744         /*
7745          * Requests require having a bitmap for each stripe.
7746          * Limit the max sectors based on this.
7747          */
7748         lim.max_hw_sectors = RAID5_MAX_REQ_STRIPES << RAID5_STRIPE_SHIFT(conf);
7749
7750         /* No restrictions on the number of segments in the request */
7751         lim.max_segments = USHRT_MAX;
7752
7753         return queue_limits_set(mddev->gendisk->queue, &lim);
7754 }
7755
7756 static int raid5_run(struct mddev *mddev)
7757 {
7758         struct r5conf *conf;
7759         int dirty_parity_disks = 0;
7760         struct md_rdev *rdev;
7761         struct md_rdev *journal_dev = NULL;
7762         sector_t reshape_offset = 0;
7763         int i;
7764         long long min_offset_diff = 0;
7765         int first = 1;
7766         int ret = -EIO;
7767
7768         if (mddev->recovery_cp != MaxSector)
7769                 pr_notice("md/raid:%s: not clean -- starting background reconstruction\n",
7770                           mdname(mddev));
7771
7772         rdev_for_each(rdev, mddev) {
7773                 long long diff;
7774
7775                 if (test_bit(Journal, &rdev->flags)) {
7776                         journal_dev = rdev;
7777                         continue;
7778                 }
7779                 if (rdev->raid_disk < 0)
7780                         continue;
7781                 diff = (rdev->new_data_offset - rdev->data_offset);
7782                 if (first) {
7783                         min_offset_diff = diff;
7784                         first = 0;
7785                 } else if (mddev->reshape_backwards &&
7786                          diff < min_offset_diff)
7787                         min_offset_diff = diff;
7788                 else if (!mddev->reshape_backwards &&
7789                          diff > min_offset_diff)
7790                         min_offset_diff = diff;
7791         }
7792
7793         if ((test_bit(MD_HAS_JOURNAL, &mddev->flags) || journal_dev) &&
7794             (mddev->bitmap_info.offset || mddev->bitmap_info.file)) {
7795                 pr_notice("md/raid:%s: array cannot have both journal and bitmap\n",
7796                           mdname(mddev));
7797                 return -EINVAL;
7798         }
7799
7800         if (mddev->reshape_position != MaxSector) {
7801                 /* Check that we can continue the reshape.
7802                  * Difficulties arise if the stripe we would write to
7803                  * next is at or after the stripe we would read from next.
7804                  * For a reshape that changes the number of devices, this
7805                  * is only possible for a very short time, and mdadm makes
7806                  * sure that time appears to have past before assembling
7807                  * the array.  So we fail if that time hasn't passed.
7808                  * For a reshape that keeps the number of devices the same
7809                  * mdadm must be monitoring the reshape can keeping the
7810                  * critical areas read-only and backed up.  It will start
7811                  * the array in read-only mode, so we check for that.
7812                  */
7813                 sector_t here_new, here_old;
7814                 int old_disks;
7815                 int max_degraded = (mddev->level == 6 ? 2 : 1);
7816                 int chunk_sectors;
7817                 int new_data_disks;
7818
7819                 if (journal_dev) {
7820                         pr_warn("md/raid:%s: don't support reshape with journal - aborting.\n",
7821                                 mdname(mddev));
7822                         return -EINVAL;
7823                 }
7824
7825                 if (mddev->new_level != mddev->level) {
7826                         pr_warn("md/raid:%s: unsupported reshape required - aborting.\n",
7827                                 mdname(mddev));
7828                         return -EINVAL;
7829                 }
7830                 old_disks = mddev->raid_disks - mddev->delta_disks;
7831                 /* reshape_position must be on a new-stripe boundary, and one
7832                  * further up in new geometry must map after here in old
7833                  * geometry.
7834                  * If the chunk sizes are different, then as we perform reshape
7835                  * in units of the largest of the two, reshape_position needs
7836                  * be a multiple of the largest chunk size times new data disks.
7837                  */
7838                 here_new = mddev->reshape_position;
7839                 chunk_sectors = max(mddev->chunk_sectors, mddev->new_chunk_sectors);
7840                 new_data_disks = mddev->raid_disks - max_degraded;
7841                 if (sector_div(here_new, chunk_sectors * new_data_disks)) {
7842                         pr_warn("md/raid:%s: reshape_position not on a stripe boundary\n",
7843                                 mdname(mddev));
7844                         return -EINVAL;
7845                 }
7846                 reshape_offset = here_new * chunk_sectors;
7847                 /* here_new is the stripe we will write to */
7848                 here_old = mddev->reshape_position;
7849                 sector_div(here_old, chunk_sectors * (old_disks-max_degraded));
7850                 /* here_old is the first stripe that we might need to read
7851                  * from */
7852                 if (mddev->delta_disks == 0) {
7853                         /* We cannot be sure it is safe to start an in-place
7854                          * reshape.  It is only safe if user-space is monitoring
7855                          * and taking constant backups.
7856                          * mdadm always starts a situation like this in
7857                          * readonly mode so it can take control before
7858                          * allowing any writes.  So just check for that.
7859                          */
7860                         if (abs(min_offset_diff) >= mddev->chunk_sectors &&
7861                             abs(min_offset_diff) >= mddev->new_chunk_sectors)
7862                                 /* not really in-place - so OK */;
7863                         else if (mddev->ro == 0) {
7864                                 pr_warn("md/raid:%s: in-place reshape must be started in read-only mode - aborting\n",
7865                                         mdname(mddev));
7866                                 return -EINVAL;
7867                         }
7868                 } else if (mddev->reshape_backwards
7869                     ? (here_new * chunk_sectors + min_offset_diff <=
7870                        here_old * chunk_sectors)
7871                     : (here_new * chunk_sectors >=
7872                        here_old * chunk_sectors + (-min_offset_diff))) {
7873                         /* Reading from the same stripe as writing to - bad */
7874                         pr_warn("md/raid:%s: reshape_position too early for auto-recovery - aborting.\n",
7875                                 mdname(mddev));
7876                         return -EINVAL;
7877                 }
7878                 pr_debug("md/raid:%s: reshape will continue\n", mdname(mddev));
7879                 /* OK, we should be able to continue; */
7880         } else {
7881                 BUG_ON(mddev->level != mddev->new_level);
7882                 BUG_ON(mddev->layout != mddev->new_layout);
7883                 BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
7884                 BUG_ON(mddev->delta_disks != 0);
7885         }
7886
7887         if (test_bit(MD_HAS_JOURNAL, &mddev->flags) &&
7888             test_bit(MD_HAS_PPL, &mddev->flags)) {
7889                 pr_warn("md/raid:%s: using journal device and PPL not allowed - disabling PPL\n",
7890                         mdname(mddev));
7891                 clear_bit(MD_HAS_PPL, &mddev->flags);
7892                 clear_bit(MD_HAS_MULTIPLE_PPLS, &mddev->flags);
7893         }
7894
7895         if (mddev->private == NULL)
7896                 conf = setup_conf(mddev);
7897         else
7898                 conf = mddev->private;
7899
7900         if (IS_ERR(conf))
7901                 return PTR_ERR(conf);
7902
7903         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
7904                 if (!journal_dev) {
7905                         pr_warn("md/raid:%s: journal disk is missing, force array readonly\n",
7906                                 mdname(mddev));
7907                         mddev->ro = 1;
7908                         set_disk_ro(mddev->gendisk, 1);
7909                 } else if (mddev->recovery_cp == MaxSector)
7910                         set_bit(MD_JOURNAL_CLEAN, &mddev->flags);
7911         }
7912
7913         conf->min_offset_diff = min_offset_diff;
7914         rcu_assign_pointer(mddev->thread, conf->thread);
7915         rcu_assign_pointer(conf->thread, NULL);
7916         mddev->private = conf;
7917
7918         for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
7919              i++) {
7920                 rdev = conf->disks[i].rdev;
7921                 if (!rdev)
7922                         continue;
7923                 if (conf->disks[i].replacement &&
7924                     conf->reshape_progress != MaxSector) {
7925                         /* replacements and reshape simply do not mix. */
7926                         pr_warn("md: cannot handle concurrent replacement and reshape.\n");
7927                         goto abort;
7928                 }
7929                 if (test_bit(In_sync, &rdev->flags))
7930                         continue;
7931                 /* This disc is not fully in-sync.  However if it
7932                  * just stored parity (beyond the recovery_offset),
7933                  * when we don't need to be concerned about the
7934                  * array being dirty.
7935                  * When reshape goes 'backwards', we never have
7936                  * partially completed devices, so we only need
7937                  * to worry about reshape going forwards.
7938                  */
7939                 /* Hack because v0.91 doesn't store recovery_offset properly. */
7940                 if (mddev->major_version == 0 &&
7941                     mddev->minor_version > 90)
7942                         rdev->recovery_offset = reshape_offset;
7943
7944                 if (rdev->recovery_offset < reshape_offset) {
7945                         /* We need to check old and new layout */
7946                         if (!only_parity(rdev->raid_disk,
7947                                          conf->algorithm,
7948                                          conf->raid_disks,
7949                                          conf->max_degraded))
7950                                 continue;
7951                 }
7952                 if (!only_parity(rdev->raid_disk,
7953                                  conf->prev_algo,
7954                                  conf->previous_raid_disks,
7955                                  conf->max_degraded))
7956                         continue;
7957                 dirty_parity_disks++;
7958         }
7959
7960         /*
7961          * 0 for a fully functional array, 1 or 2 for a degraded array.
7962          */
7963         mddev->degraded = raid5_calc_degraded(conf);
7964
7965         if (has_failed(conf)) {
7966                 pr_crit("md/raid:%s: not enough operational devices (%d/%d failed)\n",
7967                         mdname(mddev), mddev->degraded, conf->raid_disks);
7968                 goto abort;
7969         }
7970
7971         /* device size must be a multiple of chunk size */
7972         mddev->dev_sectors &= ~((sector_t)mddev->chunk_sectors - 1);
7973         mddev->resync_max_sectors = mddev->dev_sectors;
7974
7975         if (mddev->degraded > dirty_parity_disks &&
7976             mddev->recovery_cp != MaxSector) {
7977                 if (test_bit(MD_HAS_PPL, &mddev->flags))
7978                         pr_crit("md/raid:%s: starting dirty degraded array with PPL.\n",
7979                                 mdname(mddev));
7980                 else if (mddev->ok_start_degraded)
7981                         pr_crit("md/raid:%s: starting dirty degraded array - data corruption possible.\n",
7982                                 mdname(mddev));
7983                 else {
7984                         pr_crit("md/raid:%s: cannot start dirty degraded array.\n",
7985                                 mdname(mddev));
7986                         goto abort;
7987                 }
7988         }
7989
7990         pr_info("md/raid:%s: raid level %d active with %d out of %d devices, algorithm %d\n",
7991                 mdname(mddev), conf->level,
7992                 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
7993                 mddev->new_layout);
7994
7995         print_raid5_conf(conf);
7996
7997         if (conf->reshape_progress != MaxSector) {
7998                 conf->reshape_safe = conf->reshape_progress;
7999                 atomic_set(&conf->reshape_stripes, 0);
8000                 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
8001                 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
8002                 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
8003                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
8004         }
8005
8006         /* Ok, everything is just fine now */
8007         if (mddev->to_remove == &raid5_attrs_group)
8008                 mddev->to_remove = NULL;
8009         else if (mddev->kobj.sd &&
8010             sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
8011                 pr_warn("raid5: failed to create sysfs attributes for %s\n",
8012                         mdname(mddev));
8013         md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
8014
8015         if (!mddev_is_dm(mddev)) {
8016                 ret = raid5_set_limits(mddev);
8017                 if (ret)
8018                         goto abort;
8019         }
8020
8021         if (log_init(conf, journal_dev, raid5_has_ppl(conf)))
8022                 goto abort;
8023
8024         return 0;
8025 abort:
8026         md_unregister_thread(mddev, &mddev->thread);
8027         print_raid5_conf(conf);
8028         free_conf(conf);
8029         mddev->private = NULL;
8030         pr_warn("md/raid:%s: failed to run raid set.\n", mdname(mddev));
8031         return ret;
8032 }
8033
8034 static void raid5_free(struct mddev *mddev, void *priv)
8035 {
8036         struct r5conf *conf = priv;
8037
8038         free_conf(conf);
8039         mddev->to_remove = &raid5_attrs_group;
8040 }
8041
8042 static void raid5_status(struct seq_file *seq, struct mddev *mddev)
8043 {
8044         struct r5conf *conf = mddev->private;
8045         int i;
8046
8047         lockdep_assert_held(&mddev->lock);
8048
8049         seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
8050                 conf->chunk_sectors / 2, mddev->layout);
8051         seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
8052         for (i = 0; i < conf->raid_disks; i++) {
8053                 struct md_rdev *rdev = READ_ONCE(conf->disks[i].rdev);
8054
8055                 seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
8056         }
8057         seq_printf (seq, "]");
8058 }
8059
8060 static void print_raid5_conf (struct r5conf *conf)
8061 {
8062         struct md_rdev *rdev;
8063         int i;
8064
8065         pr_debug("RAID conf printout:\n");
8066         if (!conf) {
8067                 pr_debug("(conf==NULL)\n");
8068                 return;
8069         }
8070         pr_debug(" --- level:%d rd:%d wd:%d\n", conf->level,
8071                conf->raid_disks,
8072                conf->raid_disks - conf->mddev->degraded);
8073
8074         rcu_read_lock();
8075         for (i = 0; i < conf->raid_disks; i++) {
8076                 rdev = rcu_dereference(conf->disks[i].rdev);
8077                 if (rdev)
8078                         pr_debug(" disk %d, o:%d, dev:%pg\n",
8079                                i, !test_bit(Faulty, &rdev->flags),
8080                                rdev->bdev);
8081         }
8082         rcu_read_unlock();
8083 }
8084
8085 static int raid5_spare_active(struct mddev *mddev)
8086 {
8087         int i;
8088         struct r5conf *conf = mddev->private;
8089         struct md_rdev *rdev, *replacement;
8090         int count = 0;
8091         unsigned long flags;
8092
8093         for (i = 0; i < conf->raid_disks; i++) {
8094                 rdev = conf->disks[i].rdev;
8095                 replacement = conf->disks[i].replacement;
8096                 if (replacement
8097                     && replacement->recovery_offset == MaxSector
8098                     && !test_bit(Faulty, &replacement->flags)
8099                     && !test_and_set_bit(In_sync, &replacement->flags)) {
8100                         /* Replacement has just become active. */
8101                         if (!rdev
8102                             || !test_and_clear_bit(In_sync, &rdev->flags))
8103                                 count++;
8104                         if (rdev) {
8105                                 /* Replaced device not technically faulty,
8106                                  * but we need to be sure it gets removed
8107                                  * and never re-added.
8108                                  */
8109                                 set_bit(Faulty, &rdev->flags);
8110                                 sysfs_notify_dirent_safe(
8111                                         rdev->sysfs_state);
8112                         }
8113                         sysfs_notify_dirent_safe(replacement->sysfs_state);
8114                 } else if (rdev
8115                     && rdev->recovery_offset == MaxSector
8116                     && !test_bit(Faulty, &rdev->flags)
8117                     && !test_and_set_bit(In_sync, &rdev->flags)) {
8118                         count++;
8119                         sysfs_notify_dirent_safe(rdev->sysfs_state);
8120                 }
8121         }
8122         spin_lock_irqsave(&conf->device_lock, flags);
8123         mddev->degraded = raid5_calc_degraded(conf);
8124         spin_unlock_irqrestore(&conf->device_lock, flags);
8125         print_raid5_conf(conf);
8126         return count;
8127 }
8128
8129 static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
8130 {
8131         struct r5conf *conf = mddev->private;
8132         int err = 0;
8133         int number = rdev->raid_disk;
8134         struct md_rdev **rdevp;
8135         struct disk_info *p;
8136         struct md_rdev *tmp;
8137
8138         print_raid5_conf(conf);
8139         if (test_bit(Journal, &rdev->flags) && conf->log) {
8140                 /*
8141                  * we can't wait pending write here, as this is called in
8142                  * raid5d, wait will deadlock.
8143                  * neilb: there is no locking about new writes here,
8144                  * so this cannot be safe.
8145                  */
8146                 if (atomic_read(&conf->active_stripes) ||
8147                     atomic_read(&conf->r5c_cached_full_stripes) ||
8148                     atomic_read(&conf->r5c_cached_partial_stripes)) {
8149                         return -EBUSY;
8150                 }
8151                 log_exit(conf);
8152                 return 0;
8153         }
8154         if (unlikely(number >= conf->pool_size))
8155                 return 0;
8156         p = conf->disks + number;
8157         if (rdev == p->rdev)
8158                 rdevp = &p->rdev;
8159         else if (rdev == p->replacement)
8160                 rdevp = &p->replacement;
8161         else
8162                 return 0;
8163
8164         if (number >= conf->raid_disks &&
8165             conf->reshape_progress == MaxSector)
8166                 clear_bit(In_sync, &rdev->flags);
8167
8168         if (test_bit(In_sync, &rdev->flags) ||
8169             atomic_read(&rdev->nr_pending)) {
8170                 err = -EBUSY;
8171                 goto abort;
8172         }
8173         /* Only remove non-faulty devices if recovery
8174          * isn't possible.
8175          */
8176         if (!test_bit(Faulty, &rdev->flags) &&
8177             mddev->recovery_disabled != conf->recovery_disabled &&
8178             !has_failed(conf) &&
8179             (!p->replacement || p->replacement == rdev) &&
8180             number < conf->raid_disks) {
8181                 err = -EBUSY;
8182                 goto abort;
8183         }
8184         WRITE_ONCE(*rdevp, NULL);
8185         if (!err) {
8186                 err = log_modify(conf, rdev, false);
8187                 if (err)
8188                         goto abort;
8189         }
8190
8191         tmp = p->replacement;
8192         if (tmp) {
8193                 /* We must have just cleared 'rdev' */
8194                 WRITE_ONCE(p->rdev, tmp);
8195                 clear_bit(Replacement, &tmp->flags);
8196                 WRITE_ONCE(p->replacement, NULL);
8197
8198                 if (!err)
8199                         err = log_modify(conf, tmp, true);
8200         }
8201
8202         clear_bit(WantReplacement, &rdev->flags);
8203 abort:
8204
8205         print_raid5_conf(conf);
8206         return err;
8207 }
8208
8209 static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
8210 {
8211         struct r5conf *conf = mddev->private;
8212         int ret, err = -EEXIST;
8213         int disk;
8214         struct disk_info *p;
8215         struct md_rdev *tmp;
8216         int first = 0;
8217         int last = conf->raid_disks - 1;
8218
8219         if (test_bit(Journal, &rdev->flags)) {
8220                 if (conf->log)
8221                         return -EBUSY;
8222
8223                 rdev->raid_disk = 0;
8224                 /*
8225                  * The array is in readonly mode if journal is missing, so no
8226                  * write requests running. We should be safe
8227                  */
8228                 ret = log_init(conf, rdev, false);
8229                 if (ret)
8230                         return ret;
8231
8232                 ret = r5l_start(conf->log);
8233                 if (ret)
8234                         return ret;
8235
8236                 return 0;
8237         }
8238         if (mddev->recovery_disabled == conf->recovery_disabled)
8239                 return -EBUSY;
8240
8241         if (rdev->saved_raid_disk < 0 && has_failed(conf))
8242                 /* no point adding a device */
8243                 return -EINVAL;
8244
8245         if (rdev->raid_disk >= 0)
8246                 first = last = rdev->raid_disk;
8247
8248         /*
8249          * find the disk ... but prefer rdev->saved_raid_disk
8250          * if possible.
8251          */
8252         if (rdev->saved_raid_disk >= first &&
8253             rdev->saved_raid_disk <= last &&
8254             conf->disks[rdev->saved_raid_disk].rdev == NULL)
8255                 first = rdev->saved_raid_disk;
8256
8257         for (disk = first; disk <= last; disk++) {
8258                 p = conf->disks + disk;
8259                 if (p->rdev == NULL) {
8260                         clear_bit(In_sync, &rdev->flags);
8261                         rdev->raid_disk = disk;
8262                         if (rdev->saved_raid_disk != disk)
8263                                 conf->fullsync = 1;
8264                         WRITE_ONCE(p->rdev, rdev);
8265
8266                         err = log_modify(conf, rdev, true);
8267
8268                         goto out;
8269                 }
8270         }
8271         for (disk = first; disk <= last; disk++) {
8272                 p = conf->disks + disk;
8273                 tmp = p->rdev;
8274                 if (test_bit(WantReplacement, &tmp->flags) &&
8275                     mddev->reshape_position == MaxSector &&
8276                     p->replacement == NULL) {
8277                         clear_bit(In_sync, &rdev->flags);
8278                         set_bit(Replacement, &rdev->flags);
8279                         rdev->raid_disk = disk;
8280                         err = 0;
8281                         conf->fullsync = 1;
8282                         WRITE_ONCE(p->replacement, rdev);
8283                         break;
8284                 }
8285         }
8286 out:
8287         print_raid5_conf(conf);
8288         return err;
8289 }
8290
8291 static int raid5_resize(struct mddev *mddev, sector_t sectors)
8292 {
8293         /* no resync is happening, and there is enough space
8294          * on all devices, so we can resize.
8295          * We need to make sure resync covers any new space.
8296          * If the array is shrinking we should possibly wait until
8297          * any io in the removed space completes, but it hardly seems
8298          * worth it.
8299          */
8300         sector_t newsize;
8301         struct r5conf *conf = mddev->private;
8302
8303         if (raid5_has_log(conf) || raid5_has_ppl(conf))
8304                 return -EINVAL;
8305         sectors &= ~((sector_t)conf->chunk_sectors - 1);
8306         newsize = raid5_size(mddev, sectors, mddev->raid_disks);
8307         if (mddev->external_size &&
8308             mddev->array_sectors > newsize)
8309                 return -EINVAL;
8310         if (mddev->bitmap) {
8311                 int ret = md_bitmap_resize(mddev->bitmap, sectors, 0, 0);
8312                 if (ret)
8313                         return ret;
8314         }
8315         md_set_array_sectors(mddev, newsize);
8316         if (sectors > mddev->dev_sectors &&
8317             mddev->recovery_cp > mddev->dev_sectors) {
8318                 mddev->recovery_cp = mddev->dev_sectors;
8319                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
8320         }
8321         mddev->dev_sectors = sectors;
8322         mddev->resync_max_sectors = sectors;
8323         return 0;
8324 }
8325
8326 static int check_stripe_cache(struct mddev *mddev)
8327 {
8328         /* Can only proceed if there are plenty of stripe_heads.
8329          * We need a minimum of one full stripe,, and for sensible progress
8330          * it is best to have about 4 times that.
8331          * If we require 4 times, then the default 256 4K stripe_heads will
8332          * allow for chunk sizes up to 256K, which is probably OK.
8333          * If the chunk size is greater, user-space should request more
8334          * stripe_heads first.
8335          */
8336         struct r5conf *conf = mddev->private;
8337         if (((mddev->chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4
8338             > conf->min_nr_stripes ||
8339             ((mddev->new_chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4
8340             > conf->min_nr_stripes) {
8341                 pr_warn("md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
8342                         mdname(mddev),
8343                         ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
8344                          / RAID5_STRIPE_SIZE(conf))*4);
8345                 return 0;
8346         }
8347         return 1;
8348 }
8349
8350 static int check_reshape(struct mddev *mddev)
8351 {
8352         struct r5conf *conf = mddev->private;
8353
8354         if (raid5_has_log(conf) || raid5_has_ppl(conf))
8355                 return -EINVAL;
8356         if (mddev->delta_disks == 0 &&
8357             mddev->new_layout == mddev->layout &&
8358             mddev->new_chunk_sectors == mddev->chunk_sectors)
8359                 return 0; /* nothing to do */
8360         if (has_failed(conf))
8361                 return -EINVAL;
8362         if (mddev->delta_disks < 0 && mddev->reshape_position == MaxSector) {
8363                 /* We might be able to shrink, but the devices must
8364                  * be made bigger first.
8365                  * For raid6, 4 is the minimum size.
8366                  * Otherwise 2 is the minimum
8367                  */
8368                 int min = 2;
8369                 if (mddev->level == 6)
8370                         min = 4;
8371                 if (mddev->raid_disks + mddev->delta_disks < min)
8372                         return -EINVAL;
8373         }
8374
8375         if (!check_stripe_cache(mddev))
8376                 return -ENOSPC;
8377
8378         if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
8379             mddev->delta_disks > 0)
8380                 if (resize_chunks(conf,
8381                                   conf->previous_raid_disks
8382                                   + max(0, mddev->delta_disks),
8383                                   max(mddev->new_chunk_sectors,
8384                                       mddev->chunk_sectors)
8385                             ) < 0)
8386                         return -ENOMEM;
8387
8388         if (conf->previous_raid_disks + mddev->delta_disks <= conf->pool_size)
8389                 return 0; /* never bother to shrink */
8390         return resize_stripes(conf, (conf->previous_raid_disks
8391                                      + mddev->delta_disks));
8392 }
8393
8394 static int raid5_start_reshape(struct mddev *mddev)
8395 {
8396         struct r5conf *conf = mddev->private;
8397         struct md_rdev *rdev;
8398         int spares = 0;
8399         int i;
8400         unsigned long flags;
8401
8402         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
8403                 return -EBUSY;
8404
8405         if (!check_stripe_cache(mddev))
8406                 return -ENOSPC;
8407
8408         if (has_failed(conf))
8409                 return -EINVAL;
8410
8411         /* raid5 can't handle concurrent reshape and recovery */
8412         if (mddev->recovery_cp < MaxSector)
8413                 return -EBUSY;
8414         for (i = 0; i < conf->raid_disks; i++)
8415                 if (conf->disks[i].replacement)
8416                         return -EBUSY;
8417
8418         rdev_for_each(rdev, mddev) {
8419                 if (!test_bit(In_sync, &rdev->flags)
8420                     && !test_bit(Faulty, &rdev->flags))
8421                         spares++;
8422         }
8423
8424         if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
8425                 /* Not enough devices even to make a degraded array
8426                  * of that size
8427                  */
8428                 return -EINVAL;
8429
8430         /* Refuse to reduce size of the array.  Any reductions in
8431          * array size must be through explicit setting of array_size
8432          * attribute.
8433          */
8434         if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
8435             < mddev->array_sectors) {
8436                 pr_warn("md/raid:%s: array size must be reduced before number of disks\n",
8437                         mdname(mddev));
8438                 return -EINVAL;
8439         }
8440
8441         atomic_set(&conf->reshape_stripes, 0);
8442         spin_lock_irq(&conf->device_lock);
8443         write_seqcount_begin(&conf->gen_lock);
8444         conf->previous_raid_disks = conf->raid_disks;
8445         conf->raid_disks += mddev->delta_disks;
8446         conf->prev_chunk_sectors = conf->chunk_sectors;
8447         conf->chunk_sectors = mddev->new_chunk_sectors;
8448         conf->prev_algo = conf->algorithm;
8449         conf->algorithm = mddev->new_layout;
8450         conf->generation++;
8451         /* Code that selects data_offset needs to see the generation update
8452          * if reshape_progress has been set - so a memory barrier needed.
8453          */
8454         smp_mb();
8455         if (mddev->reshape_backwards)
8456                 conf->reshape_progress = raid5_size(mddev, 0, 0);
8457         else
8458                 conf->reshape_progress = 0;
8459         conf->reshape_safe = conf->reshape_progress;
8460         write_seqcount_end(&conf->gen_lock);
8461         spin_unlock_irq(&conf->device_lock);
8462
8463         /* Now make sure any requests that proceeded on the assumption
8464          * the reshape wasn't running - like Discard or Read - have
8465          * completed.
8466          */
8467         raid5_quiesce(mddev, true);
8468         raid5_quiesce(mddev, false);
8469
8470         /* Add some new drives, as many as will fit.
8471          * We know there are enough to make the newly sized array work.
8472          * Don't add devices if we are reducing the number of
8473          * devices in the array.  This is because it is not possible
8474          * to correctly record the "partially reconstructed" state of
8475          * such devices during the reshape and confusion could result.
8476          */
8477         if (mddev->delta_disks >= 0) {
8478                 rdev_for_each(rdev, mddev)
8479                         if (rdev->raid_disk < 0 &&
8480                             !test_bit(Faulty, &rdev->flags)) {
8481                                 if (raid5_add_disk(mddev, rdev) == 0) {
8482                                         if (rdev->raid_disk
8483                                             >= conf->previous_raid_disks)
8484                                                 set_bit(In_sync, &rdev->flags);
8485                                         else
8486                                                 rdev->recovery_offset = 0;
8487
8488                                         /* Failure here is OK */
8489                                         sysfs_link_rdev(mddev, rdev);
8490                                 }
8491                         } else if (rdev->raid_disk >= conf->previous_raid_disks
8492                                    && !test_bit(Faulty, &rdev->flags)) {
8493                                 /* This is a spare that was manually added */
8494                                 set_bit(In_sync, &rdev->flags);
8495                         }
8496
8497                 /* When a reshape changes the number of devices,
8498                  * ->degraded is measured against the larger of the
8499                  * pre and post number of devices.
8500                  */
8501                 spin_lock_irqsave(&conf->device_lock, flags);
8502                 mddev->degraded = raid5_calc_degraded(conf);
8503                 spin_unlock_irqrestore(&conf->device_lock, flags);
8504         }
8505         mddev->raid_disks = conf->raid_disks;
8506         mddev->reshape_position = conf->reshape_progress;
8507         set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8508
8509         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
8510         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
8511         clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
8512         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
8513         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
8514         conf->reshape_checkpoint = jiffies;
8515         md_new_event();
8516         return 0;
8517 }
8518
8519 /* This is called from the reshape thread and should make any
8520  * changes needed in 'conf'
8521  */
8522 static void end_reshape(struct r5conf *conf)
8523 {
8524
8525         if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
8526                 struct md_rdev *rdev;
8527
8528                 spin_lock_irq(&conf->device_lock);
8529                 conf->previous_raid_disks = conf->raid_disks;
8530                 md_finish_reshape(conf->mddev);
8531                 smp_wmb();
8532                 conf->reshape_progress = MaxSector;
8533                 conf->mddev->reshape_position = MaxSector;
8534                 rdev_for_each(rdev, conf->mddev)
8535                         if (rdev->raid_disk >= 0 &&
8536                             !test_bit(Journal, &rdev->flags) &&
8537                             !test_bit(In_sync, &rdev->flags))
8538                                 rdev->recovery_offset = MaxSector;
8539                 spin_unlock_irq(&conf->device_lock);
8540                 wake_up(&conf->wait_for_overlap);
8541
8542                 mddev_update_io_opt(conf->mddev,
8543                         conf->raid_disks - conf->max_degraded);
8544         }
8545 }
8546
8547 /* This is called from the raid5d thread with mddev_lock held.
8548  * It makes config changes to the device.
8549  */
8550 static void raid5_finish_reshape(struct mddev *mddev)
8551 {
8552         struct r5conf *conf = mddev->private;
8553         struct md_rdev *rdev;
8554
8555         if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
8556
8557                 if (mddev->delta_disks <= 0) {
8558                         int d;
8559                         spin_lock_irq(&conf->device_lock);
8560                         mddev->degraded = raid5_calc_degraded(conf);
8561                         spin_unlock_irq(&conf->device_lock);
8562                         for (d = conf->raid_disks ;
8563                              d < conf->raid_disks - mddev->delta_disks;
8564                              d++) {
8565                                 rdev = conf->disks[d].rdev;
8566                                 if (rdev)
8567                                         clear_bit(In_sync, &rdev->flags);
8568                                 rdev = conf->disks[d].replacement;
8569                                 if (rdev)
8570                                         clear_bit(In_sync, &rdev->flags);
8571                         }
8572                 }
8573                 mddev->layout = conf->algorithm;
8574                 mddev->chunk_sectors = conf->chunk_sectors;
8575                 mddev->reshape_position = MaxSector;
8576                 mddev->delta_disks = 0;
8577                 mddev->reshape_backwards = 0;
8578         }
8579 }
8580
8581 static void raid5_quiesce(struct mddev *mddev, int quiesce)
8582 {
8583         struct r5conf *conf = mddev->private;
8584
8585         if (quiesce) {
8586                 /* stop all writes */
8587                 lock_all_device_hash_locks_irq(conf);
8588                 /* '2' tells resync/reshape to pause so that all
8589                  * active stripes can drain
8590                  */
8591                 r5c_flush_cache(conf, INT_MAX);
8592                 /* need a memory barrier to make sure read_one_chunk() sees
8593                  * quiesce started and reverts to slow (locked) path.
8594                  */
8595                 smp_store_release(&conf->quiesce, 2);
8596                 wait_event_cmd(conf->wait_for_quiescent,
8597                                     atomic_read(&conf->active_stripes) == 0 &&
8598                                     atomic_read(&conf->active_aligned_reads) == 0,
8599                                     unlock_all_device_hash_locks_irq(conf),
8600                                     lock_all_device_hash_locks_irq(conf));
8601                 conf->quiesce = 1;
8602                 unlock_all_device_hash_locks_irq(conf);
8603                 /* allow reshape to continue */
8604                 wake_up(&conf->wait_for_overlap);
8605         } else {
8606                 /* re-enable writes */
8607                 lock_all_device_hash_locks_irq(conf);
8608                 conf->quiesce = 0;
8609                 wake_up(&conf->wait_for_quiescent);
8610                 wake_up(&conf->wait_for_overlap);
8611                 unlock_all_device_hash_locks_irq(conf);
8612         }
8613         log_quiesce(conf, quiesce);
8614 }
8615
8616 static void *raid45_takeover_raid0(struct mddev *mddev, int level)
8617 {
8618         struct r0conf *raid0_conf = mddev->private;
8619         sector_t sectors;
8620
8621         /* for raid0 takeover only one zone is supported */
8622         if (raid0_conf->nr_strip_zones > 1) {
8623                 pr_warn("md/raid:%s: cannot takeover raid0 with more than one zone.\n",
8624                         mdname(mddev));
8625                 return ERR_PTR(-EINVAL);
8626         }
8627
8628         sectors = raid0_conf->strip_zone[0].zone_end;
8629         sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
8630         mddev->dev_sectors = sectors;
8631         mddev->new_level = level;
8632         mddev->new_layout = ALGORITHM_PARITY_N;
8633         mddev->new_chunk_sectors = mddev->chunk_sectors;
8634         mddev->raid_disks += 1;
8635         mddev->delta_disks = 1;
8636         /* make sure it will be not marked as dirty */
8637         mddev->recovery_cp = MaxSector;
8638
8639         return setup_conf(mddev);
8640 }
8641
8642 static void *raid5_takeover_raid1(struct mddev *mddev)
8643 {
8644         int chunksect;
8645         void *ret;
8646
8647         if (mddev->raid_disks != 2 ||
8648             mddev->degraded > 1)
8649                 return ERR_PTR(-EINVAL);
8650
8651         /* Should check if there are write-behind devices? */
8652
8653         chunksect = 64*2; /* 64K by default */
8654
8655         /* The array must be an exact multiple of chunksize */
8656         while (chunksect && (mddev->array_sectors & (chunksect-1)))
8657                 chunksect >>= 1;
8658
8659         if ((chunksect<<9) < RAID5_STRIPE_SIZE((struct r5conf *)mddev->private))
8660                 /* array size does not allow a suitable chunk size */
8661                 return ERR_PTR(-EINVAL);
8662
8663         mddev->new_level = 5;
8664         mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
8665         mddev->new_chunk_sectors = chunksect;
8666
8667         ret = setup_conf(mddev);
8668         if (!IS_ERR(ret))
8669                 mddev_clear_unsupported_flags(mddev,
8670                         UNSUPPORTED_MDDEV_FLAGS);
8671         return ret;
8672 }
8673
8674 static void *raid5_takeover_raid6(struct mddev *mddev)
8675 {
8676         int new_layout;
8677
8678         switch (mddev->layout) {
8679         case ALGORITHM_LEFT_ASYMMETRIC_6:
8680                 new_layout = ALGORITHM_LEFT_ASYMMETRIC;
8681                 break;
8682         case ALGORITHM_RIGHT_ASYMMETRIC_6:
8683                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
8684                 break;
8685         case ALGORITHM_LEFT_SYMMETRIC_6:
8686                 new_layout = ALGORITHM_LEFT_SYMMETRIC;
8687                 break;
8688         case ALGORITHM_RIGHT_SYMMETRIC_6:
8689                 new_layout = ALGORITHM_RIGHT_SYMMETRIC;
8690                 break;
8691         case ALGORITHM_PARITY_0_6:
8692                 new_layout = ALGORITHM_PARITY_0;
8693                 break;
8694         case ALGORITHM_PARITY_N:
8695                 new_layout = ALGORITHM_PARITY_N;
8696                 break;
8697         default:
8698                 return ERR_PTR(-EINVAL);
8699         }
8700         mddev->new_level = 5;
8701         mddev->new_layout = new_layout;
8702         mddev->delta_disks = -1;
8703         mddev->raid_disks -= 1;
8704         return setup_conf(mddev);
8705 }
8706
8707 static int raid5_check_reshape(struct mddev *mddev)
8708 {
8709         /* For a 2-drive array, the layout and chunk size can be changed
8710          * immediately as not restriping is needed.
8711          * For larger arrays we record the new value - after validation
8712          * to be used by a reshape pass.
8713          */
8714         struct r5conf *conf = mddev->private;
8715         int new_chunk = mddev->new_chunk_sectors;
8716
8717         if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
8718                 return -EINVAL;
8719         if (new_chunk > 0) {
8720                 if (!is_power_of_2(new_chunk))
8721                         return -EINVAL;
8722                 if (new_chunk < (PAGE_SIZE>>9))
8723                         return -EINVAL;
8724                 if (mddev->array_sectors & (new_chunk-1))
8725                         /* not factor of array size */
8726                         return -EINVAL;
8727         }
8728
8729         /* They look valid */
8730
8731         if (mddev->raid_disks == 2) {
8732                 /* can make the change immediately */
8733                 if (mddev->new_layout >= 0) {
8734                         conf->algorithm = mddev->new_layout;
8735                         mddev->layout = mddev->new_layout;
8736                 }
8737                 if (new_chunk > 0) {
8738                         conf->chunk_sectors = new_chunk ;
8739                         mddev->chunk_sectors = new_chunk;
8740                 }
8741                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8742                 md_wakeup_thread(mddev->thread);
8743         }
8744         return check_reshape(mddev);
8745 }
8746
8747 static int raid6_check_reshape(struct mddev *mddev)
8748 {
8749         int new_chunk = mddev->new_chunk_sectors;
8750
8751         if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
8752                 return -EINVAL;
8753         if (new_chunk > 0) {
8754                 if (!is_power_of_2(new_chunk))
8755                         return -EINVAL;
8756                 if (new_chunk < (PAGE_SIZE >> 9))
8757                         return -EINVAL;
8758                 if (mddev->array_sectors & (new_chunk-1))
8759                         /* not factor of array size */
8760                         return -EINVAL;
8761         }
8762
8763         /* They look valid */
8764         return check_reshape(mddev);
8765 }
8766
8767 static void *raid5_takeover(struct mddev *mddev)
8768 {
8769         /* raid5 can take over:
8770          *  raid0 - if there is only one strip zone - make it a raid4 layout
8771          *  raid1 - if there are two drives.  We need to know the chunk size
8772          *  raid4 - trivial - just use a raid4 layout.
8773          *  raid6 - Providing it is a *_6 layout
8774          */
8775         if (mddev->level == 0)
8776                 return raid45_takeover_raid0(mddev, 5);
8777         if (mddev->level == 1)
8778                 return raid5_takeover_raid1(mddev);
8779         if (mddev->level == 4) {
8780                 mddev->new_layout = ALGORITHM_PARITY_N;
8781                 mddev->new_level = 5;
8782                 return setup_conf(mddev);
8783         }
8784         if (mddev->level == 6)
8785                 return raid5_takeover_raid6(mddev);
8786
8787         return ERR_PTR(-EINVAL);
8788 }
8789
8790 static void *raid4_takeover(struct mddev *mddev)
8791 {
8792         /* raid4 can take over:
8793          *  raid0 - if there is only one strip zone
8794          *  raid5 - if layout is right
8795          */
8796         if (mddev->level == 0)
8797                 return raid45_takeover_raid0(mddev, 4);
8798         if (mddev->level == 5 &&
8799             mddev->layout == ALGORITHM_PARITY_N) {
8800                 mddev->new_layout = 0;
8801                 mddev->new_level = 4;
8802                 return setup_conf(mddev);
8803         }
8804         return ERR_PTR(-EINVAL);
8805 }
8806
8807 static struct md_personality raid5_personality;
8808
8809 static void *raid6_takeover(struct mddev *mddev)
8810 {
8811         /* Currently can only take over a raid5.  We map the
8812          * personality to an equivalent raid6 personality
8813          * with the Q block at the end.
8814          */
8815         int new_layout;
8816
8817         if (mddev->pers != &raid5_personality)
8818                 return ERR_PTR(-EINVAL);
8819         if (mddev->degraded > 1)
8820                 return ERR_PTR(-EINVAL);
8821         if (mddev->raid_disks > 253)
8822                 return ERR_PTR(-EINVAL);
8823         if (mddev->raid_disks < 3)
8824                 return ERR_PTR(-EINVAL);
8825
8826         switch (mddev->layout) {
8827         case ALGORITHM_LEFT_ASYMMETRIC:
8828                 new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
8829                 break;
8830         case ALGORITHM_RIGHT_ASYMMETRIC:
8831                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
8832                 break;
8833         case ALGORITHM_LEFT_SYMMETRIC:
8834                 new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
8835                 break;
8836         case ALGORITHM_RIGHT_SYMMETRIC:
8837                 new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
8838                 break;
8839         case ALGORITHM_PARITY_0:
8840                 new_layout = ALGORITHM_PARITY_0_6;
8841                 break;
8842         case ALGORITHM_PARITY_N:
8843                 new_layout = ALGORITHM_PARITY_N;
8844                 break;
8845         default:
8846                 return ERR_PTR(-EINVAL);
8847         }
8848         mddev->new_level = 6;
8849         mddev->new_layout = new_layout;
8850         mddev->delta_disks = 1;
8851         mddev->raid_disks += 1;
8852         return setup_conf(mddev);
8853 }
8854
8855 static int raid5_change_consistency_policy(struct mddev *mddev, const char *buf)
8856 {
8857         struct r5conf *conf;
8858         int err;
8859
8860         err = mddev_suspend_and_lock(mddev);
8861         if (err)
8862                 return err;
8863         conf = mddev->private;
8864         if (!conf) {
8865                 mddev_unlock_and_resume(mddev);
8866                 return -ENODEV;
8867         }
8868
8869         if (strncmp(buf, "ppl", 3) == 0) {
8870                 /* ppl only works with RAID 5 */
8871                 if (!raid5_has_ppl(conf) && conf->level == 5) {
8872                         err = log_init(conf, NULL, true);
8873                         if (!err) {
8874                                 err = resize_stripes(conf, conf->pool_size);
8875                                 if (err)
8876                                         log_exit(conf);
8877                         }
8878                 } else
8879                         err = -EINVAL;
8880         } else if (strncmp(buf, "resync", 6) == 0) {
8881                 if (raid5_has_ppl(conf)) {
8882                         log_exit(conf);
8883                         err = resize_stripes(conf, conf->pool_size);
8884                 } else if (test_bit(MD_HAS_JOURNAL, &conf->mddev->flags) &&
8885                            r5l_log_disk_error(conf)) {
8886                         bool journal_dev_exists = false;
8887                         struct md_rdev *rdev;
8888
8889                         rdev_for_each(rdev, mddev)
8890                                 if (test_bit(Journal, &rdev->flags)) {
8891                                         journal_dev_exists = true;
8892                                         break;
8893                                 }
8894
8895                         if (!journal_dev_exists)
8896                                 clear_bit(MD_HAS_JOURNAL, &mddev->flags);
8897                         else  /* need remove journal device first */
8898                                 err = -EBUSY;
8899                 } else
8900                         err = -EINVAL;
8901         } else {
8902                 err = -EINVAL;
8903         }
8904
8905         if (!err)
8906                 md_update_sb(mddev, 1);
8907
8908         mddev_unlock_and_resume(mddev);
8909
8910         return err;
8911 }
8912
8913 static int raid5_start(struct mddev *mddev)
8914 {
8915         struct r5conf *conf = mddev->private;
8916
8917         return r5l_start(conf->log);
8918 }
8919
8920 /*
8921  * This is only used for dm-raid456, caller already frozen sync_thread, hence
8922  * if rehsape is still in progress, io that is waiting for reshape can never be
8923  * done now, hence wake up and handle those IO.
8924  */
8925 static void raid5_prepare_suspend(struct mddev *mddev)
8926 {
8927         struct r5conf *conf = mddev->private;
8928
8929         wake_up(&conf->wait_for_overlap);
8930 }
8931
8932 static struct md_personality raid6_personality =
8933 {
8934         .name           = "raid6",
8935         .level          = 6,
8936         .owner          = THIS_MODULE,
8937         .make_request   = raid5_make_request,
8938         .run            = raid5_run,
8939         .start          = raid5_start,
8940         .free           = raid5_free,
8941         .status         = raid5_status,
8942         .error_handler  = raid5_error,
8943         .hot_add_disk   = raid5_add_disk,
8944         .hot_remove_disk= raid5_remove_disk,
8945         .spare_active   = raid5_spare_active,
8946         .sync_request   = raid5_sync_request,
8947         .resize         = raid5_resize,
8948         .size           = raid5_size,
8949         .check_reshape  = raid6_check_reshape,
8950         .start_reshape  = raid5_start_reshape,
8951         .finish_reshape = raid5_finish_reshape,
8952         .quiesce        = raid5_quiesce,
8953         .takeover       = raid6_takeover,
8954         .change_consistency_policy = raid5_change_consistency_policy,
8955         .prepare_suspend = raid5_prepare_suspend,
8956 };
8957 static struct md_personality raid5_personality =
8958 {
8959         .name           = "raid5",
8960         .level          = 5,
8961         .owner          = THIS_MODULE,
8962         .make_request   = raid5_make_request,
8963         .run            = raid5_run,
8964         .start          = raid5_start,
8965         .free           = raid5_free,
8966         .status         = raid5_status,
8967         .error_handler  = raid5_error,
8968         .hot_add_disk   = raid5_add_disk,
8969         .hot_remove_disk= raid5_remove_disk,
8970         .spare_active   = raid5_spare_active,
8971         .sync_request   = raid5_sync_request,
8972         .resize         = raid5_resize,
8973         .size           = raid5_size,
8974         .check_reshape  = raid5_check_reshape,
8975         .start_reshape  = raid5_start_reshape,
8976         .finish_reshape = raid5_finish_reshape,
8977         .quiesce        = raid5_quiesce,
8978         .takeover       = raid5_takeover,
8979         .change_consistency_policy = raid5_change_consistency_policy,
8980         .prepare_suspend = raid5_prepare_suspend,
8981 };
8982
8983 static struct md_personality raid4_personality =
8984 {
8985         .name           = "raid4",
8986         .level          = 4,
8987         .owner          = THIS_MODULE,
8988         .make_request   = raid5_make_request,
8989         .run            = raid5_run,
8990         .start          = raid5_start,
8991         .free           = raid5_free,
8992         .status         = raid5_status,
8993         .error_handler  = raid5_error,
8994         .hot_add_disk   = raid5_add_disk,
8995         .hot_remove_disk= raid5_remove_disk,
8996         .spare_active   = raid5_spare_active,
8997         .sync_request   = raid5_sync_request,
8998         .resize         = raid5_resize,
8999         .size           = raid5_size,
9000         .check_reshape  = raid5_check_reshape,
9001         .start_reshape  = raid5_start_reshape,
9002         .finish_reshape = raid5_finish_reshape,
9003         .quiesce        = raid5_quiesce,
9004         .takeover       = raid4_takeover,
9005         .change_consistency_policy = raid5_change_consistency_policy,
9006         .prepare_suspend = raid5_prepare_suspend,
9007 };
9008
9009 static int __init raid5_init(void)
9010 {
9011         int ret;
9012
9013         raid5_wq = alloc_workqueue("raid5wq",
9014                 WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE|WQ_SYSFS, 0);
9015         if (!raid5_wq)
9016                 return -ENOMEM;
9017
9018         ret = cpuhp_setup_state_multi(CPUHP_MD_RAID5_PREPARE,
9019                                       "md/raid5:prepare",
9020                                       raid456_cpu_up_prepare,
9021                                       raid456_cpu_dead);
9022         if (ret) {
9023                 destroy_workqueue(raid5_wq);
9024                 return ret;
9025         }
9026         register_md_personality(&raid6_personality);
9027         register_md_personality(&raid5_personality);
9028         register_md_personality(&raid4_personality);
9029         return 0;
9030 }
9031
9032 static void raid5_exit(void)
9033 {
9034         unregister_md_personality(&raid6_personality);
9035         unregister_md_personality(&raid5_personality);
9036         unregister_md_personality(&raid4_personality);
9037         cpuhp_remove_multi_state(CPUHP_MD_RAID5_PREPARE);
9038         destroy_workqueue(raid5_wq);
9039 }
9040
9041 module_init(raid5_init);
9042 module_exit(raid5_exit);
9043 MODULE_LICENSE("GPL");
9044 MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
9045 MODULE_ALIAS("md-personality-4"); /* RAID5 */
9046 MODULE_ALIAS("md-raid5");
9047 MODULE_ALIAS("md-raid4");
9048 MODULE_ALIAS("md-level-5");
9049 MODULE_ALIAS("md-level-4");
9050 MODULE_ALIAS("md-personality-8"); /* RAID6 */
9051 MODULE_ALIAS("md-raid6");
9052 MODULE_ALIAS("md-level-6");
9053
9054 /* This used to be two separate modules, they were: */
9055 MODULE_ALIAS("raid5");
9056 MODULE_ALIAS("raid6");