drivers/md/raid5.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * raid5.c : Multiple Devices driver for Linux
   4  *         Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
   5  *         Copyright (C) 1999, 2000 Ingo Molnar
   6  *         Copyright (C) 2002, 2003 H. Peter Anvin
   7  *
   8  * RAID-4/5/6 management functions.
   9  * Thanks to Penguin Computing for making the RAID-6 development possible
  10  * by donating a test server!
  11  */
  12
  13 /*
  14  * BITMAP UNPLUGGING:
  15  *
  16  * The sequencing for updating the bitmap reliably is a little
  17  * subtle (and I got it wrong the first time) so it deserves some
  18  * explanation.
  19  *
  20  * We group bitmap updates into batches.  Each batch has a number.
  21  * We may write out several batches at once, but that isn't very important.
  22  * conf->seq_write is the number of the last batch successfully written.
  23  * conf->seq_flush is the number of the last batch that was closed to
  24  *    new additions.
  25  * When we discover that we will need to write to any block in a stripe
  26  * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
  27  * the number of the batch it will be in. This is seq_flush+1.
  28  * When we are ready to do a write, if that batch hasn't been written yet,
  29  *   we plug the array and queue the stripe for later.
  30  * When an unplug happens, we increment bm_flush, thus closing the current
  31  *   batch.
  32  * When we notice that bm_flush > bm_write, we write out all pending updates
  33  * to the bitmap, and advance bm_write to where bm_flush was.
  34  * This may occasionally write a bit out twice, but is sure never to
  35  * miss any bits.
  36  */
  37
  38 #include <linux/blkdev.h>
  39 #include <linux/kthread.h>
  40 #include <linux/raid/pq.h>
  41 #include <linux/async_tx.h>
  42 #include <linux/module.h>
  43 #include <linux/async.h>
  44 #include <linux/seq_file.h>
  45 #include <linux/cpu.h>
  46 #include <linux/slab.h>
  47 #include <linux/ratelimit.h>
  48 #include <linux/nodemask.h>
  49
  50 #include <trace/events/block.h>
  51 #include <linux/list_sort.h>
  52
  53 #include "md.h"
  54 #include "raid5.h"
  55 #include "raid0.h"
  56 #include "md-bitmap.h"
  57 #include "raid5-log.h"
  58
  59 #define UNSUPPORTED_MDDEV_FLAGS (1L << MD_FAILFAST_SUPPORTED)
  60
  61 #define cpu_to_group(cpu) cpu_to_node(cpu)
  62 #define ANY_GROUP NUMA_NO_NODE
  63
  64 static bool devices_handle_discard_safely = false;
  65 module_param(devices_handle_discard_safely, bool, 0644);
  66 MODULE_PARM_DESC(devices_handle_discard_safely,
  67                  "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
  68 static struct workqueue_struct *raid5_wq;
  69
  70 static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
  71 {
  72         int hash = (sect >> STRIPE_SHIFT) & HASH_MASK;
  73         return &conf->stripe_hashtbl[hash];
  74 }
  75
  76 static inline int stripe_hash_locks_hash(sector_t sect)
  77 {
  78         return (sect >> STRIPE_SHIFT) & STRIPE_HASH_LOCKS_MASK;
  79 }
  80
  81 static inline void lock_device_hash_lock(struct r5conf *conf, int hash)
  82 {
  83         spin_lock_irq(conf->hash_locks + hash);
  84         spin_lock(&conf->device_lock);
  85 }
  86
  87 static inline void unlock_device_hash_lock(struct r5conf *conf, int hash)
  88 {
  89         spin_unlock(&conf->device_lock);
  90         spin_unlock_irq(conf->hash_locks + hash);
  91 }
  92
  93 static inline void lock_all_device_hash_locks_irq(struct r5conf *conf)
  94 {
  95         int i;
  96         spin_lock_irq(conf->hash_locks);
  97         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
  98                 spin_lock_nest_lock(conf->hash_locks + i, conf->hash_locks);
  99         spin_lock(&conf->device_lock);
 100 }
 101
 102 static inline void unlock_all_device_hash_locks_irq(struct r5conf *conf)
 103 {
 104         int i;
 105         spin_unlock(&conf->device_lock);
 106         for (i = NR_STRIPE_HASH_LOCKS - 1; i; i--)
 107                 spin_unlock(conf->hash_locks + i);
 108         spin_unlock_irq(conf->hash_locks);
 109 }
 110
 111 /* Find first data disk in a raid6 stripe */
 112 static inline int raid6_d0(struct stripe_head *sh)
 113 {
 114         if (sh->ddf_layout)
 115                 /* ddf always start from first device */
 116                 return 0;
 117         /* md starts just after Q block */
 118         if (sh->qd_idx == sh->disks - 1)
 119                 return 0;
 120         else
 121                 return sh->qd_idx + 1;
 122 }
 123 static inline int raid6_next_disk(int disk, int raid_disks)
 124 {
 125         disk++;
 126         return (disk < raid_disks) ? disk : 0;
 127 }
 128
 129 /* When walking through the disks in a raid5, starting at raid6_d0,
 130  * We need to map each disk to a 'slot', where the data disks are slot
 131  * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
 132  * is raid_disks-1.  This help does that mapping.
 133  */
 134 static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
 135                              int *count, int syndrome_disks)
 136 {
 137         int slot = *count;
 138
 139         if (sh->ddf_layout)
 140                 (*count)++;
 141         if (idx == sh->pd_idx)
 142                 return syndrome_disks;
 143         if (idx == sh->qd_idx)
 144                 return syndrome_disks + 1;
 145         if (!sh->ddf_layout)
 146                 (*count)++;
 147         return slot;
 148 }
 149
 150 static void print_raid5_conf (struct r5conf *conf);
 151
 152 static int stripe_operations_active(struct stripe_head *sh)
 153 {
 154         return sh->check_state || sh->reconstruct_state ||
 155                test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
 156                test_bit(STRIPE_COMPUTE_RUN, &sh->state);
 157 }
 158
 159 static bool stripe_is_lowprio(struct stripe_head *sh)
 160 {
 161         return (test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) ||
 162                 test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) &&
 163                !test_bit(STRIPE_R5C_CACHING, &sh->state);
 164 }
 165
 166 static void raid5_wakeup_stripe_thread(struct stripe_head *sh)
 167 {
 168         struct r5conf *conf = sh->raid_conf;
 169         struct r5worker_group *group;
 170         int thread_cnt;
 171         int i, cpu = sh->cpu;
 172
 173         if (!cpu_online(cpu)) {
 174                 cpu = cpumask_any(cpu_online_mask);
 175                 sh->cpu = cpu;
 176         }
 177
 178         if (list_empty(&sh->lru)) {
 179                 struct r5worker_group *group;
 180                 group = conf->worker_groups + cpu_to_group(cpu);
 181                 if (stripe_is_lowprio(sh))
 182                         list_add_tail(&sh->lru, &group->loprio_list);
 183                 else
 184                         list_add_tail(&sh->lru, &group->handle_list);
 185                 group->stripes_cnt++;
 186                 sh->group = group;
 187         }
 188
 189         if (conf->worker_cnt_per_group == 0) {
 190                 md_wakeup_thread(conf->mddev->thread);
 191                 return;
 192         }
 193
 194         group = conf->worker_groups + cpu_to_group(sh->cpu);
 195
 196         group->workers[0].working = true;
 197         /* at least one worker should run to avoid race */
 198         queue_work_on(sh->cpu, raid5_wq, &group->workers[0].work);
 199
 200         thread_cnt = group->stripes_cnt / MAX_STRIPE_BATCH - 1;
 201         /* wakeup more workers */
 202         for (i = 1; i < conf->worker_cnt_per_group && thread_cnt > 0; i++) {
 203                 if (group->workers[i].working == false) {
 204                         group->workers[i].working = true;
 205                         queue_work_on(sh->cpu, raid5_wq,
 206                                       &group->workers[i].work);
 207                         thread_cnt--;
 208                 }
 209         }
 210 }
 211
 212 static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh,
 213                               struct list_head *temp_inactive_list)
 214 {
 215         int i;
 216         int injournal = 0;      /* number of date pages with R5_InJournal */
 217
 218         BUG_ON(!list_empty(&sh->lru));
 219         BUG_ON(atomic_read(&conf->active_stripes)==0);
 220
 221         if (r5c_is_writeback(conf->log))
 222                 for (i = sh->disks; i--; )
 223                         if (test_bit(R5_InJournal, &sh->dev[i].flags))
 224                                 injournal++;
 225         /*
 226          * In the following cases, the stripe cannot be released to cached
 227          * lists. Therefore, we make the stripe write out and set
 228          * STRIPE_HANDLE:
 229          *   1. when quiesce in r5c write back;
 230          *   2. when resync is requested fot the stripe.
 231          */
 232         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) ||
 233             (conf->quiesce && r5c_is_writeback(conf->log) &&
 234              !test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0)) {
 235                 if (test_bit(STRIPE_R5C_CACHING, &sh->state))
 236                         r5c_make_stripe_write_out(sh);
 237                 set_bit(STRIPE_HANDLE, &sh->state);
 238         }
 239
 240         if (test_bit(STRIPE_HANDLE, &sh->state)) {
 241                 if (test_bit(STRIPE_DELAYED, &sh->state) &&
 242                     !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 243                         list_add_tail(&sh->lru, &conf->delayed_list);
 244                 else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
 245                            sh->bm_seq - conf->seq_write > 0)
 246                         list_add_tail(&sh->lru, &conf->bitmap_list);
 247                 else {
 248                         clear_bit(STRIPE_DELAYED, &sh->state);
 249                         clear_bit(STRIPE_BIT_DELAY, &sh->state);
 250                         if (conf->worker_cnt_per_group == 0) {
 251                                 if (stripe_is_lowprio(sh))
 252                                         list_add_tail(&sh->lru,
 253                                                         &conf->loprio_list);
 254                                 else
 255                                         list_add_tail(&sh->lru,
 256                                                         &conf->handle_list);
 257                         } else {
 258                                 raid5_wakeup_stripe_thread(sh);
 259                                 return;
 260                         }
 261                 }
 262                 md_wakeup_thread(conf->mddev->thread);
 263         } else {
 264                 BUG_ON(stripe_operations_active(sh));
 265                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 266                         if (atomic_dec_return(&conf->preread_active_stripes)
 267                             < IO_THRESHOLD)
 268                                 md_wakeup_thread(conf->mddev->thread);
 269                 atomic_dec(&conf->active_stripes);
 270                 if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
 271                         if (!r5c_is_writeback(conf->log))
 272                                 list_add_tail(&sh->lru, temp_inactive_list);
 273                         else {
 274                                 WARN_ON(test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags));
 275                                 if (injournal == 0)
 276                                         list_add_tail(&sh->lru, temp_inactive_list);
 277                                 else if (injournal == conf->raid_disks - conf->max_degraded) {
 278                                         /* full stripe */
 279                                         if (!test_and_set_bit(STRIPE_R5C_FULL_STRIPE, &sh->state))
 280                                                 atomic_inc(&conf->r5c_cached_full_stripes);
 281                                         if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
 282                                                 atomic_dec(&conf->r5c_cached_partial_stripes);
 283                                         list_add_tail(&sh->lru, &conf->r5c_full_stripe_list);
 284                                         r5c_check_cached_full_stripe(conf);
 285                                 } else
 286                                         /*
 287                                          * STRIPE_R5C_PARTIAL_STRIPE is set in
 288                                          * r5c_try_caching_write(). No need to
 289                                          * set it again.
 290                                          */
 291                                         list_add_tail(&sh->lru, &conf->r5c_partial_stripe_list);
 292                         }
 293                 }
 294         }
 295 }
 296
 297 static void __release_stripe(struct r5conf *conf, struct stripe_head *sh,
 298                              struct list_head *temp_inactive_list)
 299 {
 300         if (atomic_dec_and_test(&sh->count))
 301                 do_release_stripe(conf, sh, temp_inactive_list);
 302 }
 303
 304 /*
 305  * @hash could be NR_STRIPE_HASH_LOCKS, then we have a list of inactive_list
 306  *
 307  * Be careful: Only one task can add/delete stripes from temp_inactive_list at
 308  * given time. Adding stripes only takes device lock, while deleting stripes
 309  * only takes hash lock.
 310  */
 311 static void release_inactive_stripe_list(struct r5conf *conf,
 312                                          struct list_head *temp_inactive_list,
 313                                          int hash)
 314 {
 315         int size;
 316         bool do_wakeup = false;
 317         unsigned long flags;
 318
 319         if (hash == NR_STRIPE_HASH_LOCKS) {
 320                 size = NR_STRIPE_HASH_LOCKS;
 321                 hash = NR_STRIPE_HASH_LOCKS - 1;
 322         } else
 323                 size = 1;
 324         while (size) {
 325                 struct list_head *list = &temp_inactive_list[size - 1];
 326
 327                 /*
 328                  * We don't hold any lock here yet, raid5_get_active_stripe() might
 329                  * remove stripes from the list
 330                  */
 331                 if (!list_empty_careful(list)) {
 332                         spin_lock_irqsave(conf->hash_locks + hash, flags);
 333                         if (list_empty(conf->inactive_list + hash) &&
 334                             !list_empty(list))
 335                                 atomic_dec(&conf->empty_inactive_list_nr);
 336                         list_splice_tail_init(list, conf->inactive_list + hash);
 337                         do_wakeup = true;
 338                         spin_unlock_irqrestore(conf->hash_locks + hash, flags);
 339                 }
 340                 size--;
 341                 hash--;
 342         }
 343
 344         if (do_wakeup) {
 345                 wake_up(&conf->wait_for_stripe);
 346                 if (atomic_read(&conf->active_stripes) == 0)
 347                         wake_up(&conf->wait_for_quiescent);
 348                 if (conf->retry_read_aligned)
 349                         md_wakeup_thread(conf->mddev->thread);
 350         }
 351 }
 352
 353 /* should hold conf->device_lock already */
 354 static int release_stripe_list(struct r5conf *conf,
 355                                struct list_head *temp_inactive_list)
 356 {
 357         struct stripe_head *sh, *t;
 358         int count = 0;
 359         struct llist_node *head;
 360
 361         head = llist_del_all(&conf->released_stripes);
 362         head = llist_reverse_order(head);
 363         llist_for_each_entry_safe(sh, t, head, release_list) {
 364                 int hash;
 365
 366                 /* sh could be readded after STRIPE_ON_RELEASE_LIST is cleard */
 367                 smp_mb();
 368                 clear_bit(STRIPE_ON_RELEASE_LIST, &sh->state);
 369                 /*
 370                  * Don't worry the bit is set here, because if the bit is set
 371                  * again, the count is always > 1. This is true for
 372                  * STRIPE_ON_UNPLUG_LIST bit too.
 373                  */
 374                 hash = sh->hash_lock_index;
 375                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
 376                 count++;
 377         }
 378
 379         return count;
 380 }
 381
 382 void raid5_release_stripe(struct stripe_head *sh)
 383 {
 384         struct r5conf *conf = sh->raid_conf;
 385         unsigned long flags;
 386         struct list_head list;
 387         int hash;
 388         bool wakeup;
 389
 390         /* Avoid release_list until the last reference.
 391          */
 392         if (atomic_add_unless(&sh->count, -1, 1))
 393                 return;
 394
 395         if (unlikely(!conf->mddev->thread) ||
 396                 test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state))
 397                 goto slow_path;
 398         wakeup = llist_add(&sh->release_list, &conf->released_stripes);
 399         if (wakeup)
 400                 md_wakeup_thread(conf->mddev->thread);
 401         return;
 402 slow_path:
 403         /* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */
 404         if (atomic_dec_and_lock_irqsave(&sh->count, &conf->device_lock, flags)) {
 405                 INIT_LIST_HEAD(&list);
 406                 hash = sh->hash_lock_index;
 407                 do_release_stripe(conf, sh, &list);
 408                 spin_unlock_irqrestore(&conf->device_lock, flags);
 409                 release_inactive_stripe_list(conf, &list, hash);
 410         }
 411 }
 412
 413 static inline void remove_hash(struct stripe_head *sh)
 414 {
 415         pr_debug("remove_hash(), stripe %llu\n",
 416                 (unsigned long long)sh->sector);
 417
 418         hlist_del_init(&sh->hash);
 419 }
 420
 421 static inline void insert_hash(struct r5conf *conf, struct stripe_head *sh)
 422 {
 423         struct hlist_head *hp = stripe_hash(conf, sh->sector);
 424
 425         pr_debug("insert_hash(), stripe %llu\n",
 426                 (unsigned long long)sh->sector);
 427
 428         hlist_add_head(&sh->hash, hp);
 429 }
 430
 431 /* find an idle stripe, make sure it is unhashed, and return it. */
 432 static struct stripe_head *get_free_stripe(struct r5conf *conf, int hash)
 433 {
 434         struct stripe_head *sh = NULL;
 435         struct list_head *first;
 436
 437         if (list_empty(conf->inactive_list + hash))
 438                 goto out;
 439         first = (conf->inactive_list + hash)->next;
 440         sh = list_entry(first, struct stripe_head, lru);
 441         list_del_init(first);
 442         remove_hash(sh);
 443         atomic_inc(&conf->active_stripes);
 444         BUG_ON(hash != sh->hash_lock_index);
 445         if (list_empty(conf->inactive_list + hash))
 446                 atomic_inc(&conf->empty_inactive_list_nr);
 447 out:
 448         return sh;
 449 }
 450
 451 static void shrink_buffers(struct stripe_head *sh)
 452 {
 453         struct page *p;
 454         int i;
 455         int num = sh->raid_conf->pool_size;
 456
 457         for (i = 0; i < num ; i++) {
 458                 WARN_ON(sh->dev[i].page != sh->dev[i].orig_page);
 459                 p = sh->dev[i].page;
 460                 if (!p)
 461                         continue;
 462                 sh->dev[i].page = NULL;
 463                 put_page(p);
 464         }
 465 }
 466
 467 static int grow_buffers(struct stripe_head *sh, gfp_t gfp)
 468 {
 469         int i;
 470         int num = sh->raid_conf->pool_size;
 471
 472         for (i = 0; i < num; i++) {
 473                 struct page *page;
 474
 475                 if (!(page = alloc_page(gfp))) {
 476                         return 1;
 477                 }
 478                 sh->dev[i].page = page;
 479                 sh->dev[i].orig_page = page;
 480         }
 481
 482         return 0;
 483 }
 484
 485 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
 486                             struct stripe_head *sh);
 487
 488 static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
 489 {
 490         struct r5conf *conf = sh->raid_conf;
 491         int i, seq;
 492
 493         BUG_ON(atomic_read(&sh->count) != 0);
 494         BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
 495         BUG_ON(stripe_operations_active(sh));
 496         BUG_ON(sh->batch_head);
 497
 498         pr_debug("init_stripe called, stripe %llu\n",
 499                 (unsigned long long)sector);
 500 retry:
 501         seq = read_seqcount_begin(&conf->gen_lock);
 502         sh->generation = conf->generation - previous;
 503         sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
 504         sh->sector = sector;
 505         stripe_set_idx(sector, conf, previous, sh);
 506         sh->state = 0;
 507
 508         for (i = sh->disks; i--; ) {
 509                 struct r5dev *dev = &sh->dev[i];
 510
 511                 if (dev->toread || dev->read || dev->towrite || dev->written ||
 512                     test_bit(R5_LOCKED, &dev->flags)) {
 513                         pr_err("sector=%llx i=%d %p %p %p %p %d\n",
 514                                (unsigned long long)sh->sector, i, dev->toread,
 515                                dev->read, dev->towrite, dev->written,
 516                                test_bit(R5_LOCKED, &dev->flags));
 517                         WARN_ON(1);
 518                 }
 519                 dev->flags = 0;
 520                 dev->sector = raid5_compute_blocknr(sh, i, previous);
 521         }
 522         if (read_seqcount_retry(&conf->gen_lock, seq))
 523                 goto retry;
 524         sh->overwrite_disks = 0;
 525         insert_hash(conf, sh);
 526         sh->cpu = smp_processor_id();
 527         set_bit(STRIPE_BATCH_READY, &sh->state);
 528 }
 529
 530 static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
 531                                          short generation)
 532 {
 533         struct stripe_head *sh;
 534
 535         pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
 536         hlist_for_each_entry(sh, stripe_hash(conf, sector), hash)
 537                 if (sh->sector == sector && sh->generation == generation)
 538                         return sh;
 539         pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
 540         return NULL;
 541 }
 542
 543 /*
 544  * Need to check if array has failed when deciding whether to:
 545  *  - start an array
 546  *  - remove non-faulty devices
 547  *  - add a spare
 548  *  - allow a reshape
 549  * This determination is simple when no reshape is happening.
 550  * However if there is a reshape, we need to carefully check
 551  * both the before and after sections.
 552  * This is because some failed devices may only affect one
 553  * of the two sections, and some non-in_sync devices may
 554  * be insync in the section most affected by failed devices.
 555  */
 556 int raid5_calc_degraded(struct r5conf *conf)
 557 {
 558         int degraded, degraded2;
 559         int i;
 560
 561         rcu_read_lock();
 562         degraded = 0;
 563         for (i = 0; i < conf->previous_raid_disks; i++) {
 564                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 565                 if (rdev && test_bit(Faulty, &rdev->flags))
 566                         rdev = rcu_dereference(conf->disks[i].replacement);
 567                 if (!rdev || test_bit(Faulty, &rdev->flags))
 568                         degraded++;
 569                 else if (test_bit(In_sync, &rdev->flags))
 570                         ;
 571                 else
 572                         /* not in-sync or faulty.
 573                          * If the reshape increases the number of devices,
 574                          * this is being recovered by the reshape, so
 575                          * this 'previous' section is not in_sync.
 576                          * If the number of devices is being reduced however,
 577                          * the device can only be part of the array if
 578                          * we are reverting a reshape, so this section will
 579                          * be in-sync.
 580                          */
 581                         if (conf->raid_disks >= conf->previous_raid_disks)
 582                                 degraded++;
 583         }
 584         rcu_read_unlock();
 585         if (conf->raid_disks == conf->previous_raid_disks)
 586                 return degraded;
 587         rcu_read_lock();
 588         degraded2 = 0;
 589         for (i = 0; i < conf->raid_disks; i++) {
 590                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 591                 if (rdev && test_bit(Faulty, &rdev->flags))
 592                         rdev = rcu_dereference(conf->disks[i].replacement);
 593                 if (!rdev || test_bit(Faulty, &rdev->flags))
 594                         degraded2++;
 595                 else if (test_bit(In_sync, &rdev->flags))
 596                         ;
 597                 else
 598                         /* not in-sync or faulty.
 599                          * If reshape increases the number of devices, this
 600                          * section has already been recovered, else it
 601                          * almost certainly hasn't.
 602                          */
 603                         if (conf->raid_disks <= conf->previous_raid_disks)
 604                                 degraded2++;
 605         }
 606         rcu_read_unlock();
 607         if (degraded2 > degraded)
 608                 return degraded2;
 609         return degraded;
 610 }
 611
 612 static int has_failed(struct r5conf *conf)
 613 {
 614         int degraded;
 615
 616         if (conf->mddev->reshape_position == MaxSector)
 617                 return conf->mddev->degraded > conf->max_degraded;
 618
 619         degraded = raid5_calc_degraded(conf);
 620         if (degraded > conf->max_degraded)
 621                 return 1;
 622         return 0;
 623 }
 624
 625 struct stripe_head *
 626 raid5_get_active_stripe(struct r5conf *conf, sector_t sector,
 627                         int previous, int noblock, int noquiesce)
 628 {
 629         struct stripe_head *sh;
 630         int hash = stripe_hash_locks_hash(sector);
 631         int inc_empty_inactive_list_flag;
 632
 633         pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
 634
 635         spin_lock_irq(conf->hash_locks + hash);
 636
 637         do {
 638                 wait_event_lock_irq(conf->wait_for_quiescent,
 639                                     conf->quiesce == 0 || noquiesce,
 640                                     *(conf->hash_locks + hash));
 641                 sh = __find_stripe(conf, sector, conf->generation - previous);
 642                 if (!sh) {
 643                         if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state)) {
 644                                 sh = get_free_stripe(conf, hash);
 645                                 if (!sh && !test_bit(R5_DID_ALLOC,
 646                                                      &conf->cache_state))
 647                                         set_bit(R5_ALLOC_MORE,
 648                                                 &conf->cache_state);
 649                         }
 650                         if (noblock && sh == NULL)
 651                                 break;
 652
 653                         r5c_check_stripe_cache_usage(conf);
 654                         if (!sh) {
 655                                 set_bit(R5_INACTIVE_BLOCKED,
 656                                         &conf->cache_state);
 657                                 r5l_wake_reclaim(conf->log, 0);
 658                                 wait_event_lock_irq(
 659                                         conf->wait_for_stripe,
 660                                         !list_empty(conf->inactive_list + hash) &&
 661                                         (atomic_read(&conf->active_stripes)
 662                                          < (conf->max_nr_stripes * 3 / 4)
 663                                          || !test_bit(R5_INACTIVE_BLOCKED,
 664                                                       &conf->cache_state)),
 665                                         *(conf->hash_locks + hash));
 666                                 clear_bit(R5_INACTIVE_BLOCKED,
 667                                           &conf->cache_state);
 668                         } else {
 669                                 init_stripe(sh, sector, previous);
 670                                 atomic_inc(&sh->count);
 671                         }
 672                 } else if (!atomic_inc_not_zero(&sh->count)) {
 673                         spin_lock(&conf->device_lock);
 674                         if (!atomic_read(&sh->count)) {
 675                                 if (!test_bit(STRIPE_HANDLE, &sh->state))
 676                                         atomic_inc(&conf->active_stripes);
 677                                 BUG_ON(list_empty(&sh->lru) &&
 678                                        !test_bit(STRIPE_EXPANDING, &sh->state));
 679                                 inc_empty_inactive_list_flag = 0;
 680                                 if (!list_empty(conf->inactive_list + hash))
 681                                         inc_empty_inactive_list_flag = 1;
 682                                 list_del_init(&sh->lru);
 683                                 if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 684                                         atomic_inc(&conf->empty_inactive_list_nr);
 685                                 if (sh->group) {
 686                                         sh->group->stripes_cnt--;
 687                                         sh->group = NULL;
 688                                 }
 689                         }
 690                         atomic_inc(&sh->count);
 691                         spin_unlock(&conf->device_lock);
 692                 }
 693         } while (sh == NULL);
 694
 695         spin_unlock_irq(conf->hash_locks + hash);
 696         return sh;
 697 }
 698
 699 static bool is_full_stripe_write(struct stripe_head *sh)
 700 {
 701         BUG_ON(sh->overwrite_disks > (sh->disks - sh->raid_conf->max_degraded));
 702         return sh->overwrite_disks == (sh->disks - sh->raid_conf->max_degraded);
 703 }
 704
 705 static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 706                 __acquires(&sh1->stripe_lock)
 707                 __acquires(&sh2->stripe_lock)
 708 {
 709         if (sh1 > sh2) {
 710                 spin_lock_irq(&sh2->stripe_lock);
 711                 spin_lock_nested(&sh1->stripe_lock, 1);
 712         } else {
 713                 spin_lock_irq(&sh1->stripe_lock);
 714                 spin_lock_nested(&sh2->stripe_lock, 1);
 715         }
 716 }
 717
 718 static void unlock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 719                 __releases(&sh1->stripe_lock)
 720                 __releases(&sh2->stripe_lock)
 721 {
 722         spin_unlock(&sh1->stripe_lock);
 723         spin_unlock_irq(&sh2->stripe_lock);
 724 }
 725
 726 /* Only freshly new full stripe normal write stripe can be added to a batch list */
 727 static bool stripe_can_batch(struct stripe_head *sh)
 728 {
 729         struct r5conf *conf = sh->raid_conf;
 730
 731         if (raid5_has_log(conf) || raid5_has_ppl(conf))
 732                 return false;
 733         return test_bit(STRIPE_BATCH_READY, &sh->state) &&
 734                 !test_bit(STRIPE_BITMAP_PENDING, &sh->state) &&
 735                 is_full_stripe_write(sh);
 736 }
 737
 738 /* we only do back search */
 739 static void stripe_add_to_batch_list(struct r5conf *conf, struct stripe_head *sh)
 740 {
 741         struct stripe_head *head;
 742         sector_t head_sector, tmp_sec;
 743         int hash;
 744         int dd_idx;
 745         int inc_empty_inactive_list_flag;
 746
 747         /* Don't cross chunks, so stripe pd_idx/qd_idx is the same */
 748         tmp_sec = sh->sector;
 749         if (!sector_div(tmp_sec, conf->chunk_sectors))
 750                 return;
 751         head_sector = sh->sector - STRIPE_SECTORS;
 752
 753         hash = stripe_hash_locks_hash(head_sector);
 754         spin_lock_irq(conf->hash_locks + hash);
 755         head = __find_stripe(conf, head_sector, conf->generation);
 756         if (head && !atomic_inc_not_zero(&head->count)) {
 757                 spin_lock(&conf->device_lock);
 758                 if (!atomic_read(&head->count)) {
 759                         if (!test_bit(STRIPE_HANDLE, &head->state))
 760                                 atomic_inc(&conf->active_stripes);
 761                         BUG_ON(list_empty(&head->lru) &&
 762                                !test_bit(STRIPE_EXPANDING, &head->state));
 763                         inc_empty_inactive_list_flag = 0;
 764                         if (!list_empty(conf->inactive_list + hash))
 765                                 inc_empty_inactive_list_flag = 1;
 766                         list_del_init(&head->lru);
 767                         if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 768                                 atomic_inc(&conf->empty_inactive_list_nr);
 769                         if (head->group) {
 770                                 head->group->stripes_cnt--;
 771                                 head->group = NULL;
 772                         }
 773                 }
 774                 atomic_inc(&head->count);
 775                 spin_unlock(&conf->device_lock);
 776         }
 777         spin_unlock_irq(conf->hash_locks + hash);
 778
 779         if (!head)
 780                 return;
 781         if (!stripe_can_batch(head))
 782                 goto out;
 783
 784         lock_two_stripes(head, sh);
 785         /* clear_batch_ready clear the flag */
 786         if (!stripe_can_batch(head) || !stripe_can_batch(sh))
 787                 goto unlock_out;
 788
 789         if (sh->batch_head)
 790                 goto unlock_out;
 791
 792         dd_idx = 0;
 793         while (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
 794                 dd_idx++;
 795         if (head->dev[dd_idx].towrite->bi_opf != sh->dev[dd_idx].towrite->bi_opf ||
 796             bio_op(head->dev[dd_idx].towrite) != bio_op(sh->dev[dd_idx].towrite))
 797                 goto unlock_out;
 798
 799         if (head->batch_head) {
 800                 spin_lock(&head->batch_head->batch_lock);
 801                 /* This batch list is already running */
 802                 if (!stripe_can_batch(head)) {
 803                         spin_unlock(&head->batch_head->batch_lock);
 804                         goto unlock_out;
 805                 }
 806                 /*
 807                  * We must assign batch_head of this stripe within the
 808                  * batch_lock, otherwise clear_batch_ready of batch head
 809                  * stripe could clear BATCH_READY bit of this stripe and
 810                  * this stripe->batch_head doesn't get assigned, which
 811                  * could confuse clear_batch_ready for this stripe
 812                  */
 813                 sh->batch_head = head->batch_head;
 814
 815                 /*
 816                  * at this point, head's BATCH_READY could be cleared, but we
 817                  * can still add the stripe to batch list
 818                  */
 819                 list_add(&sh->batch_list, &head->batch_list);
 820                 spin_unlock(&head->batch_head->batch_lock);
 821         } else {
 822                 head->batch_head = head;
 823                 sh->batch_head = head->batch_head;
 824                 spin_lock(&head->batch_lock);
 825                 list_add_tail(&sh->batch_list, &head->batch_list);
 826                 spin_unlock(&head->batch_lock);
 827         }
 828
 829         if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 830                 if (atomic_dec_return(&conf->preread_active_stripes)
 831                     < IO_THRESHOLD)
 832                         md_wakeup_thread(conf->mddev->thread);
 833
 834         if (test_and_clear_bit(STRIPE_BIT_DELAY, &sh->state)) {
 835                 int seq = sh->bm_seq;
 836                 if (test_bit(STRIPE_BIT_DELAY, &sh->batch_head->state) &&
 837                     sh->batch_head->bm_seq > seq)
 838                         seq = sh->batch_head->bm_seq;
 839                 set_bit(STRIPE_BIT_DELAY, &sh->batch_head->state);
 840                 sh->batch_head->bm_seq = seq;
 841         }
 842
 843         atomic_inc(&sh->count);
 844 unlock_out:
 845         unlock_two_stripes(head, sh);
 846 out:
 847         raid5_release_stripe(head);
 848 }
 849
 850 /* Determine if 'data_offset' or 'new_data_offset' should be used
 851  * in this stripe_head.
 852  */
 853 static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
 854 {
 855         sector_t progress = conf->reshape_progress;
 856         /* Need a memory barrier to make sure we see the value
 857          * of conf->generation, or ->data_offset that was set before
 858          * reshape_progress was updated.
 859          */
 860         smp_rmb();
 861         if (progress == MaxSector)
 862                 return 0;
 863         if (sh->generation == conf->generation - 1)
 864                 return 0;
 865         /* We are in a reshape, and this is a new-generation stripe,
 866          * so use new_data_offset.
 867          */
 868         return 1;
 869 }
 870
 871 static void dispatch_bio_list(struct bio_list *tmp)
 872 {
 873         struct bio *bio;
 874
 875         while ((bio = bio_list_pop(tmp)))
 876                 generic_make_request(bio);
 877 }
 878
 879 static int cmp_stripe(void *priv, struct list_head *a, struct list_head *b)
 880 {
 881         const struct r5pending_data *da = list_entry(a,
 882                                 struct r5pending_data, sibling);
 883         const struct r5pending_data *db = list_entry(b,
 884                                 struct r5pending_data, sibling);
 885         if (da->sector > db->sector)
 886                 return 1;
 887         if (da->sector < db->sector)
 888                 return -1;
 889         return 0;
 890 }
 891
 892 static void dispatch_defer_bios(struct r5conf *conf, int target,
 893                                 struct bio_list *list)
 894 {
 895         struct r5pending_data *data;
 896         struct list_head *first, *next = NULL;
 897         int cnt = 0;
 898
 899         if (conf->pending_data_cnt == 0)
 900                 return;
 901
 902         list_sort(NULL, &conf->pending_list, cmp_stripe);
 903
 904         first = conf->pending_list.next;
 905
 906         /* temporarily move the head */
 907         if (conf->next_pending_data)
 908                 list_move_tail(&conf->pending_list,
 909                                 &conf->next_pending_data->sibling);
 910
 911         while (!list_empty(&conf->pending_list)) {
 912                 data = list_first_entry(&conf->pending_list,
 913                         struct r5pending_data, sibling);
 914                 if (&data->sibling == first)
 915                         first = data->sibling.next;
 916                 next = data->sibling.next;
 917
 918                 bio_list_merge(list, &data->bios);
 919                 list_move(&data->sibling, &conf->free_list);
 920                 cnt++;
 921                 if (cnt >= target)
 922                         break;
 923         }
 924         conf->pending_data_cnt -= cnt;
 925         BUG_ON(conf->pending_data_cnt < 0 || cnt < target);
 926
 927         if (next != &conf->pending_list)
 928                 conf->next_pending_data = list_entry(next,
 929                                 struct r5pending_data, sibling);
 930         else
 931                 conf->next_pending_data = NULL;
 932         /* list isn't empty */
 933         if (first != &conf->pending_list)
 934                 list_move_tail(&conf->pending_list, first);
 935 }
 936
 937 static void flush_deferred_bios(struct r5conf *conf)
 938 {
 939         struct bio_list tmp = BIO_EMPTY_LIST;
 940
 941         if (conf->pending_data_cnt == 0)
 942                 return;
 943
 944         spin_lock(&conf->pending_bios_lock);
 945         dispatch_defer_bios(conf, conf->pending_data_cnt, &tmp);
 946         BUG_ON(conf->pending_data_cnt != 0);
 947         spin_unlock(&conf->pending_bios_lock);
 948
 949         dispatch_bio_list(&tmp);
 950 }
 951
 952 static void defer_issue_bios(struct r5conf *conf, sector_t sector,
 953                                 struct bio_list *bios)
 954 {
 955         struct bio_list tmp = BIO_EMPTY_LIST;
 956         struct r5pending_data *ent;
 957
 958         spin_lock(&conf->pending_bios_lock);
 959         ent = list_first_entry(&conf->free_list, struct r5pending_data,
 960                                                         sibling);
 961         list_move_tail(&ent->sibling, &conf->pending_list);
 962         ent->sector = sector;
 963         bio_list_init(&ent->bios);
 964         bio_list_merge(&ent->bios, bios);
 965         conf->pending_data_cnt++;
 966         if (conf->pending_data_cnt >= PENDING_IO_MAX)
 967                 dispatch_defer_bios(conf, PENDING_IO_ONE_FLUSH, &tmp);
 968
 969         spin_unlock(&conf->pending_bios_lock);
 970
 971         dispatch_bio_list(&tmp);
 972 }
 973
 974 static void
 975 raid5_end_read_request(struct bio *bi);
 976 static void
 977 raid5_end_write_request(struct bio *bi);
 978
 979 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 980 {
 981         struct r5conf *conf = sh->raid_conf;
 982         int i, disks = sh->disks;
 983         struct stripe_head *head_sh = sh;
 984         struct bio_list pending_bios = BIO_EMPTY_LIST;
 985         bool should_defer;
 986
 987         might_sleep();
 988
 989         if (log_stripe(sh, s) == 0)
 990                 return;
 991
 992         should_defer = conf->batch_bio_dispatch && conf->group_cnt;
 993
 994         for (i = disks; i--; ) {
 995                 int op, op_flags = 0;
 996                 int replace_only = 0;
 997                 struct bio *bi, *rbi;
 998                 struct md_rdev *rdev, *rrdev = NULL;
 999
1000                 sh = head_sh;
1001                 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
1002                         op = REQ_OP_WRITE;
1003                         if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
1004                                 op_flags = REQ_FUA;
1005                         if (test_bit(R5_Discard, &sh->dev[i].flags))
1006                                 op = REQ_OP_DISCARD;
1007                 } else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1008                         op = REQ_OP_READ;
1009                 else if (test_and_clear_bit(R5_WantReplace,
1010                                             &sh->dev[i].flags)) {
1011                         op = REQ_OP_WRITE;
1012                         replace_only = 1;
1013                 } else
1014                         continue;
1015                 if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
1016                         op_flags |= REQ_SYNC;
1017
1018 again:
1019                 bi = &sh->dev[i].req;
1020                 rbi = &sh->dev[i].rreq; /* For writing to replacement */
1021
1022                 rcu_read_lock();
1023                 rrdev = rcu_dereference(conf->disks[i].replacement);
1024                 smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
1025                 rdev = rcu_dereference(conf->disks[i].rdev);
1026                 if (!rdev) {
1027                         rdev = rrdev;
1028                         rrdev = NULL;
1029                 }
1030                 if (op_is_write(op)) {
1031                         if (replace_only)
1032                                 rdev = NULL;
1033                         if (rdev == rrdev)
1034                                 /* We raced and saw duplicates */
1035                                 rrdev = NULL;
1036                 } else {
1037                         if (test_bit(R5_ReadRepl, &head_sh->dev[i].flags) && rrdev)
1038                                 rdev = rrdev;
1039                         rrdev = NULL;
1040                 }
1041
1042                 if (rdev && test_bit(Faulty, &rdev->flags))
1043                         rdev = NULL;
1044                 if (rdev)
1045                         atomic_inc(&rdev->nr_pending);
1046                 if (rrdev && test_bit(Faulty, &rrdev->flags))
1047                         rrdev = NULL;
1048                 if (rrdev)
1049                         atomic_inc(&rrdev->nr_pending);
1050                 rcu_read_unlock();
1051
1052                 /* We have already checked bad blocks for reads.  Now
1053                  * need to check for writes.  We never accept write errors
1054                  * on the replacement, so we don't to check rrdev.
1055                  */
1056                 while (op_is_write(op) && rdev &&
1057                        test_bit(WriteErrorSeen, &rdev->flags)) {
1058                         sector_t first_bad;
1059                         int bad_sectors;
1060                         int bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
1061                                               &first_bad, &bad_sectors);
1062                         if (!bad)
1063                                 break;
1064
1065                         if (bad < 0) {
1066                                 set_bit(BlockedBadBlocks, &rdev->flags);
1067                                 if (!conf->mddev->external &&
1068                                     conf->mddev->sb_flags) {
1069                                         /* It is very unlikely, but we might
1070                                          * still need to write out the
1071                                          * bad block log - better give it
1072                                          * a chance*/
1073                                         md_check_recovery(conf->mddev);
1074                                 }
1075                                 /*
1076                                  * Because md_wait_for_blocked_rdev
1077                                  * will dec nr_pending, we must
1078                                  * increment it first.
1079                                  */
1080                                 atomic_inc(&rdev->nr_pending);
1081                                 md_wait_for_blocked_rdev(rdev, conf->mddev);
1082                         } else {
1083                                 /* Acknowledged bad block - skip the write */
1084                                 rdev_dec_pending(rdev, conf->mddev);
1085                                 rdev = NULL;
1086                         }
1087                 }
1088
1089                 if (rdev) {
1090                         if (s->syncing || s->expanding || s->expanded
1091                             || s->replacing)
1092                                 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
1093
1094                         set_bit(STRIPE_IO_STARTED, &sh->state);
1095
1096                         bio_set_dev(bi, rdev->bdev);
1097                         bio_set_op_attrs(bi, op, op_flags);
1098                         bi->bi_end_io = op_is_write(op)
1099                                 ? raid5_end_write_request
1100                                 : raid5_end_read_request;
1101                         bi->bi_private = sh;
1102
1103                         pr_debug("%s: for %llu schedule op %d on disc %d\n",
1104                                 __func__, (unsigned long long)sh->sector,
1105                                 bi->bi_opf, i);
1106                         atomic_inc(&sh->count);
1107                         if (sh != head_sh)
1108                                 atomic_inc(&head_sh->count);
1109                         if (use_new_offset(conf, sh))
1110                                 bi->bi_iter.bi_sector = (sh->sector
1111                                                  + rdev->new_data_offset);
1112                         else
1113                                 bi->bi_iter.bi_sector = (sh->sector
1114                                                  + rdev->data_offset);
1115                         if (test_bit(R5_ReadNoMerge, &head_sh->dev[i].flags))
1116                                 bi->bi_opf |= REQ_NOMERGE;
1117
1118                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1119                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1120
1121                         if (!op_is_write(op) &&
1122                             test_bit(R5_InJournal, &sh->dev[i].flags))
1123                                 /*
1124                                  * issuing read for a page in journal, this
1125                                  * must be preparing for prexor in rmw; read
1126                                  * the data into orig_page
1127                                  */
1128                                 sh->dev[i].vec.bv_page = sh->dev[i].orig_page;
1129                         else
1130                                 sh->dev[i].vec.bv_page = sh->dev[i].page;
1131                         bi->bi_vcnt = 1;
1132                         bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1133                         bi->bi_io_vec[0].bv_offset = 0;
1134                         bi->bi_iter.bi_size = STRIPE_SIZE;
1135                         bi->bi_write_hint = sh->dev[i].write_hint;
1136                         if (!rrdev)
1137                                 sh->dev[i].write_hint = RWF_WRITE_LIFE_NOT_SET;
1138                         /*
1139                          * If this is discard request, set bi_vcnt 0. We don't
1140                          * want to confuse SCSI because SCSI will replace payload
1141                          */
1142                         if (op == REQ_OP_DISCARD)
1143                                 bi->bi_vcnt = 0;
1144                         if (rrdev)
1145                                 set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
1146
1147                         if (conf->mddev->gendisk)
1148                                 trace_block_bio_remap(bi->bi_disk->queue,
1149                                                       bi, disk_devt(conf->mddev->gendisk),
1150                                                       sh->dev[i].sector);
1151                         if (should_defer && op_is_write(op))
1152                                 bio_list_add(&pending_bios, bi);
1153                         else
1154                                 generic_make_request(bi);
1155                 }
1156                 if (rrdev) {
1157                         if (s->syncing || s->expanding || s->expanded
1158                             || s->replacing)
1159                                 md_sync_acct(rrdev->bdev, STRIPE_SECTORS);
1160
1161                         set_bit(STRIPE_IO_STARTED, &sh->state);
1162
1163                         bio_set_dev(rbi, rrdev->bdev);
1164                         bio_set_op_attrs(rbi, op, op_flags);
1165                         BUG_ON(!op_is_write(op));
1166                         rbi->bi_end_io = raid5_end_write_request;
1167                         rbi->bi_private = sh;
1168
1169                         pr_debug("%s: for %llu schedule op %d on "
1170                                  "replacement disc %d\n",
1171                                 __func__, (unsigned long long)sh->sector,
1172                                 rbi->bi_opf, i);
1173                         atomic_inc(&sh->count);
1174                         if (sh != head_sh)
1175                                 atomic_inc(&head_sh->count);
1176                         if (use_new_offset(conf, sh))
1177                                 rbi->bi_iter.bi_sector = (sh->sector
1178                                                   + rrdev->new_data_offset);
1179                         else
1180                                 rbi->bi_iter.bi_sector = (sh->sector
1181                                                   + rrdev->data_offset);
1182                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1183                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1184                         sh->dev[i].rvec.bv_page = sh->dev[i].page;
1185                         rbi->bi_vcnt = 1;
1186                         rbi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1187                         rbi->bi_io_vec[0].bv_offset = 0;
1188                         rbi->bi_iter.bi_size = STRIPE_SIZE;
1189                         rbi->bi_write_hint = sh->dev[i].write_hint;
1190                         sh->dev[i].write_hint = RWF_WRITE_LIFE_NOT_SET;
1191                         /*
1192                          * If this is discard request, set bi_vcnt 0. We don't
1193                          * want to confuse SCSI because SCSI will replace payload
1194                          */
1195                         if (op == REQ_OP_DISCARD)
1196                                 rbi->bi_vcnt = 0;
1197                         if (conf->mddev->gendisk)
1198                                 trace_block_bio_remap(rbi->bi_disk->queue,
1199                                                       rbi, disk_devt(conf->mddev->gendisk),
1200                                                       sh->dev[i].sector);
1201                         if (should_defer && op_is_write(op))
1202                                 bio_list_add(&pending_bios, rbi);
1203                         else
1204                                 generic_make_request(rbi);
1205                 }
1206                 if (!rdev && !rrdev) {
1207                         if (op_is_write(op))
1208                                 set_bit(STRIPE_DEGRADED, &sh->state);
1209                         pr_debug("skip op %d on disc %d for sector %llu\n",
1210                                 bi->bi_opf, i, (unsigned long long)sh->sector);
1211                         clear_bit(R5_LOCKED, &sh->dev[i].flags);
1212                         set_bit(STRIPE_HANDLE, &sh->state);
1213                 }
1214
1215                 if (!head_sh->batch_head)
1216                         continue;
1217                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1218                                       batch_list);
1219                 if (sh != head_sh)
1220                         goto again;
1221         }
1222
1223         if (should_defer && !bio_list_empty(&pending_bios))
1224                 defer_issue_bios(conf, head_sh->sector, &pending_bios);
1225 }
1226
1227 static struct dma_async_tx_descriptor *
1228 async_copy_data(int frombio, struct bio *bio, struct page **page,
1229         sector_t sector, struct dma_async_tx_descriptor *tx,
1230         struct stripe_head *sh, int no_skipcopy)
1231 {
1232         struct bio_vec bvl;
1233         struct bvec_iter iter;
1234         struct page *bio_page;
1235         int page_offset;
1236         struct async_submit_ctl submit;
1237         enum async_tx_flags flags = 0;
1238
1239         if (bio->bi_iter.bi_sector >= sector)
1240                 page_offset = (signed)(bio->bi_iter.bi_sector - sector) * 512;
1241         else
1242                 page_offset = (signed)(sector - bio->bi_iter.bi_sector) * -512;
1243
1244         if (frombio)
1245                 flags |= ASYNC_TX_FENCE;
1246         init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
1247
1248         bio_for_each_segment(bvl, bio, iter) {
1249                 int len = bvl.bv_len;
1250                 int clen;
1251                 int b_offset = 0;
1252
1253                 if (page_offset < 0) {
1254                         b_offset = -page_offset;
1255                         page_offset += b_offset;
1256                         len -= b_offset;
1257                 }
1258
1259                 if (len > 0 && page_offset + len > STRIPE_SIZE)
1260                         clen = STRIPE_SIZE - page_offset;
1261                 else
1262                         clen = len;
1263
1264                 if (clen > 0) {
1265                         b_offset += bvl.bv_offset;
1266                         bio_page = bvl.bv_page;
1267                         if (frombio) {
1268                                 if (sh->raid_conf->skip_copy &&
1269                                     b_offset == 0 && page_offset == 0 &&
1270                                     clen == STRIPE_SIZE &&
1271                                     !no_skipcopy)
1272                                         *page = bio_page;
1273                                 else
1274                                         tx = async_memcpy(*page, bio_page, page_offset,
1275                                                   b_offset, clen, &submit);
1276                         } else
1277                                 tx = async_memcpy(bio_page, *page, b_offset,
1278                                                   page_offset, clen, &submit);
1279                 }
1280                 /* chain the operations */
1281                 submit.depend_tx = tx;
1282
1283                 if (clen < len) /* hit end of page */
1284                         break;
1285                 page_offset +=  len;
1286         }
1287
1288         return tx;
1289 }
1290
1291 static void ops_complete_biofill(void *stripe_head_ref)
1292 {
1293         struct stripe_head *sh = stripe_head_ref;
1294         int i;
1295
1296         pr_debug("%s: stripe %llu\n", __func__,
1297                 (unsigned long long)sh->sector);
1298
1299         /* clear completed biofills */
1300         for (i = sh->disks; i--; ) {
1301                 struct r5dev *dev = &sh->dev[i];
1302
1303                 /* acknowledge completion of a biofill operation */
1304                 /* and check if we need to reply to a read request,
1305                  * new R5_Wantfill requests are held off until
1306                  * !STRIPE_BIOFILL_RUN
1307                  */
1308                 if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
1309                         struct bio *rbi, *rbi2;
1310
1311                         BUG_ON(!dev->read);
1312                         rbi = dev->read;
1313                         dev->read = NULL;
1314                         while (rbi && rbi->bi_iter.bi_sector <
1315                                 dev->sector + STRIPE_SECTORS) {
1316                                 rbi2 = r5_next_bio(rbi, dev->sector);
1317                                 bio_endio(rbi);
1318                                 rbi = rbi2;
1319                         }
1320                 }
1321         }
1322         clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
1323
1324         set_bit(STRIPE_HANDLE, &sh->state);
1325         raid5_release_stripe(sh);
1326 }
1327
1328 static void ops_run_biofill(struct stripe_head *sh)
1329 {
1330         struct dma_async_tx_descriptor *tx = NULL;
1331         struct async_submit_ctl submit;
1332         int i;
1333
1334         BUG_ON(sh->batch_head);
1335         pr_debug("%s: stripe %llu\n", __func__,
1336                 (unsigned long long)sh->sector);
1337
1338         for (i = sh->disks; i--; ) {
1339                 struct r5dev *dev = &sh->dev[i];
1340                 if (test_bit(R5_Wantfill, &dev->flags)) {
1341                         struct bio *rbi;
1342                         spin_lock_irq(&sh->stripe_lock);
1343                         dev->read = rbi = dev->toread;
1344                         dev->toread = NULL;
1345                         spin_unlock_irq(&sh->stripe_lock);
1346                         while (rbi && rbi->bi_iter.bi_sector <
1347                                 dev->sector + STRIPE_SECTORS) {
1348                                 tx = async_copy_data(0, rbi, &dev->page,
1349                                                      dev->sector, tx, sh, 0);
1350                                 rbi = r5_next_bio(rbi, dev->sector);
1351                         }
1352                 }
1353         }
1354
1355         atomic_inc(&sh->count);
1356         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
1357         async_trigger_callback(&submit);
1358 }
1359
1360 static void mark_target_uptodate(struct stripe_head *sh, int target)
1361 {
1362         struct r5dev *tgt;
1363
1364         if (target < 0)
1365                 return;
1366
1367         tgt = &sh->dev[target];
1368         set_bit(R5_UPTODATE, &tgt->flags);
1369         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1370         clear_bit(R5_Wantcompute, &tgt->flags);
1371 }
1372
1373 static void ops_complete_compute(void *stripe_head_ref)
1374 {
1375         struct stripe_head *sh = stripe_head_ref;
1376
1377         pr_debug("%s: stripe %llu\n", __func__,
1378                 (unsigned long long)sh->sector);
1379
1380         /* mark the computed target(s) as uptodate */
1381         mark_target_uptodate(sh, sh->ops.target);
1382         mark_target_uptodate(sh, sh->ops.target2);
1383
1384         clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
1385         if (sh->check_state == check_state_compute_run)
1386                 sh->check_state = check_state_compute_result;
1387         set_bit(STRIPE_HANDLE, &sh->state);
1388         raid5_release_stripe(sh);
1389 }
1390
1391 /* return a pointer to the address conversion region of the scribble buffer */
1392 static struct page **to_addr_page(struct raid5_percpu *percpu, int i)
1393 {
1394         return percpu->scribble + i * percpu->scribble_obj_size;
1395 }
1396
1397 /* return a pointer to the address conversion region of the scribble buffer */
1398 static addr_conv_t *to_addr_conv(struct stripe_head *sh,
1399                                  struct raid5_percpu *percpu, int i)
1400 {
1401         return (void *) (to_addr_page(percpu, i) + sh->disks + 2);
1402 }
1403
1404 static struct dma_async_tx_descriptor *
1405 ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
1406 {
1407         int disks = sh->disks;
1408         struct page **xor_srcs = to_addr_page(percpu, 0);
1409         int target = sh->ops.target;
1410         struct r5dev *tgt = &sh->dev[target];
1411         struct page *xor_dest = tgt->page;
1412         int count = 0;
1413         struct dma_async_tx_descriptor *tx;
1414         struct async_submit_ctl submit;
1415         int i;
1416
1417         BUG_ON(sh->batch_head);
1418
1419         pr_debug("%s: stripe %llu block: %d\n",
1420                 __func__, (unsigned long long)sh->sector, target);
1421         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1422
1423         for (i = disks; i--; )
1424                 if (i != target)
1425                         xor_srcs[count++] = sh->dev[i].page;
1426
1427         atomic_inc(&sh->count);
1428
1429         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
1430                           ops_complete_compute, sh, to_addr_conv(sh, percpu, 0));
1431         if (unlikely(count == 1))
1432                 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
1433         else
1434                 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1435
1436         return tx;
1437 }
1438
1439 /* set_syndrome_sources - populate source buffers for gen_syndrome
1440  * @srcs - (struct page *) array of size sh->disks
1441  * @sh - stripe_head to parse
1442  *
1443  * Populates srcs in proper layout order for the stripe and returns the
1444  * 'count' of sources to be used in a call to async_gen_syndrome.  The P
1445  * destination buffer is recorded in srcs[count] and the Q destination
1446  * is recorded in srcs[count+1]].
1447  */
1448 static int set_syndrome_sources(struct page **srcs,
1449                                 struct stripe_head *sh,
1450                                 int srctype)
1451 {
1452         int disks = sh->disks;
1453         int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
1454         int d0_idx = raid6_d0(sh);
1455         int count;
1456         int i;
1457
1458         for (i = 0; i < disks; i++)
1459                 srcs[i] = NULL;
1460
1461         count = 0;
1462         i = d0_idx;
1463         do {
1464                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1465                 struct r5dev *dev = &sh->dev[i];
1466
1467                 if (i == sh->qd_idx || i == sh->pd_idx ||
1468                     (srctype == SYNDROME_SRC_ALL) ||
1469                     (srctype == SYNDROME_SRC_WANT_DRAIN &&
1470                      (test_bit(R5_Wantdrain, &dev->flags) ||
1471                       test_bit(R5_InJournal, &dev->flags))) ||
1472                     (srctype == SYNDROME_SRC_WRITTEN &&
1473                      (dev->written ||
1474                       test_bit(R5_InJournal, &dev->flags)))) {
1475                         if (test_bit(R5_InJournal, &dev->flags))
1476                                 srcs[slot] = sh->dev[i].orig_page;
1477                         else
1478                                 srcs[slot] = sh->dev[i].page;
1479                 }
1480                 i = raid6_next_disk(i, disks);
1481         } while (i != d0_idx);
1482
1483         return syndrome_disks;
1484 }
1485
1486 static struct dma_async_tx_descriptor *
1487 ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
1488 {
1489         int disks = sh->disks;
1490         struct page **blocks = to_addr_page(percpu, 0);
1491         int target;
1492         int qd_idx = sh->qd_idx;
1493         struct dma_async_tx_descriptor *tx;
1494         struct async_submit_ctl submit;
1495         struct r5dev *tgt;
1496         struct page *dest;
1497         int i;
1498         int count;
1499
1500         BUG_ON(sh->batch_head);
1501         if (sh->ops.target < 0)
1502                 target = sh->ops.target2;
1503         else if (sh->ops.target2 < 0)
1504                 target = sh->ops.target;
1505         else
1506                 /* we should only have one valid target */
1507                 BUG();
1508         BUG_ON(target < 0);
1509         pr_debug("%s: stripe %llu block: %d\n",
1510                 __func__, (unsigned long long)sh->sector, target);
1511
1512         tgt = &sh->dev[target];
1513         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1514         dest = tgt->page;
1515
1516         atomic_inc(&sh->count);
1517
1518         if (target == qd_idx) {
1519                 count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1520                 blocks[count] = NULL; /* regenerating p is not necessary */
1521                 BUG_ON(blocks[count+1] != dest); /* q should already be set */
1522                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1523                                   ops_complete_compute, sh,
1524                                   to_addr_conv(sh, percpu, 0));
1525                 tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
1526         } else {
1527                 /* Compute any data- or p-drive using XOR */
1528                 count = 0;
1529                 for (i = disks; i-- ; ) {
1530                         if (i == target || i == qd_idx)
1531                                 continue;
1532                         blocks[count++] = sh->dev[i].page;
1533                 }
1534
1535                 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1536                                   NULL, ops_complete_compute, sh,
1537                                   to_addr_conv(sh, percpu, 0));
1538                 tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
1539         }
1540
1541         return tx;
1542 }
1543
1544 static struct dma_async_tx_descriptor *
1545 ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
1546 {
1547         int i, count, disks = sh->disks;
1548         int syndrome_disks = sh->ddf_layout ? disks : disks-2;
1549         int d0_idx = raid6_d0(sh);
1550         int faila = -1, failb = -1;
1551         int target = sh->ops.target;
1552         int target2 = sh->ops.target2;
1553         struct r5dev *tgt = &sh->dev[target];
1554         struct r5dev *tgt2 = &sh->dev[target2];
1555         struct dma_async_tx_descriptor *tx;
1556         struct page **blocks = to_addr_page(percpu, 0);
1557         struct async_submit_ctl submit;
1558
1559         BUG_ON(sh->batch_head);
1560         pr_debug("%s: stripe %llu block1: %d block2: %d\n",
1561                  __func__, (unsigned long long)sh->sector, target, target2);
1562         BUG_ON(target < 0 || target2 < 0);
1563         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1564         BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
1565
1566         /* we need to open-code set_syndrome_sources to handle the
1567          * slot number conversion for 'faila' and 'failb'
1568          */
1569         for (i = 0; i < disks ; i++)
1570                 blocks[i] = NULL;
1571         count = 0;
1572         i = d0_idx;
1573         do {
1574                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1575
1576                 blocks[slot] = sh->dev[i].page;
1577
1578                 if (i == target)
1579                         faila = slot;
1580                 if (i == target2)
1581                         failb = slot;
1582                 i = raid6_next_disk(i, disks);
1583         } while (i != d0_idx);
1584
1585         BUG_ON(faila == failb);
1586         if (failb < faila)
1587                 swap(faila, failb);
1588         pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
1589                  __func__, (unsigned long long)sh->sector, faila, failb);
1590
1591         atomic_inc(&sh->count);
1592
1593         if (failb == syndrome_disks+1) {
1594                 /* Q disk is one of the missing disks */
1595                 if (faila == syndrome_disks) {
1596                         /* Missing P+Q, just recompute */
1597                         init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1598                                           ops_complete_compute, sh,
1599                                           to_addr_conv(sh, percpu, 0));
1600                         return async_gen_syndrome(blocks, 0, syndrome_disks+2,
1601                                                   STRIPE_SIZE, &submit);
1602                 } else {
1603                         struct page *dest;
1604                         int data_target;
1605                         int qd_idx = sh->qd_idx;
1606
1607                         /* Missing D+Q: recompute D from P, then recompute Q */
1608                         if (target == qd_idx)
1609                                 data_target = target2;
1610                         else
1611                                 data_target = target;
1612
1613                         count = 0;
1614                         for (i = disks; i-- ; ) {
1615                                 if (i == data_target || i == qd_idx)
1616                                         continue;
1617                                 blocks[count++] = sh->dev[i].page;
1618                         }
1619                         dest = sh->dev[data_target].page;
1620                         init_async_submit(&submit,
1621                                           ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1622                                           NULL, NULL, NULL,
1623                                           to_addr_conv(sh, percpu, 0));
1624                         tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
1625                                        &submit);
1626
1627                         count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1628                         init_async_submit(&submit, ASYNC_TX_FENCE, tx,
1629                                           ops_complete_compute, sh,
1630                                           to_addr_conv(sh, percpu, 0));
1631                         return async_gen_syndrome(blocks, 0, count+2,
1632                                                   STRIPE_SIZE, &submit);
1633                 }
1634         } else {
1635                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1636                                   ops_complete_compute, sh,
1637                                   to_addr_conv(sh, percpu, 0));
1638                 if (failb == syndrome_disks) {
1639                         /* We're missing D+P. */
1640                         return async_raid6_datap_recov(syndrome_disks+2,
1641                                                        STRIPE_SIZE, faila,
1642                                                        blocks, &submit);
1643                 } else {
1644                         /* We're missing D+D. */
1645                         return async_raid6_2data_recov(syndrome_disks+2,
1646                                                        STRIPE_SIZE, faila, failb,
1647                                                        blocks, &submit);
1648                 }
1649         }
1650 }
1651
1652 static void ops_complete_prexor(void *stripe_head_ref)
1653 {
1654         struct stripe_head *sh = stripe_head_ref;
1655
1656         pr_debug("%s: stripe %llu\n", __func__,
1657                 (unsigned long long)sh->sector);
1658
1659         if (r5c_is_writeback(sh->raid_conf->log))
1660                 /*
1661                  * raid5-cache write back uses orig_page during prexor.
1662                  * After prexor, it is time to free orig_page
1663                  */
1664                 r5c_release_extra_page(sh);
1665 }
1666
1667 static struct dma_async_tx_descriptor *
1668 ops_run_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
1669                 struct dma_async_tx_descriptor *tx)
1670 {
1671         int disks = sh->disks;
1672         struct page **xor_srcs = to_addr_page(percpu, 0);
1673         int count = 0, pd_idx = sh->pd_idx, i;
1674         struct async_submit_ctl submit;
1675
1676         /* existing parity data subtracted */
1677         struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1678
1679         BUG_ON(sh->batch_head);
1680         pr_debug("%s: stripe %llu\n", __func__,
1681                 (unsigned long long)sh->sector);
1682
1683         for (i = disks; i--; ) {
1684                 struct r5dev *dev = &sh->dev[i];
1685                 /* Only process blocks that are known to be uptodate */
1686                 if (test_bit(R5_InJournal, &dev->flags))
1687                         xor_srcs[count++] = dev->orig_page;
1688                 else if (test_bit(R5_Wantdrain, &dev->flags))
1689                         xor_srcs[count++] = dev->page;
1690         }
1691
1692         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1693                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1694         tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1695
1696         return tx;
1697 }
1698
1699 static struct dma_async_tx_descriptor *
1700 ops_run_prexor6(struct stripe_head *sh, struct raid5_percpu *percpu,
1701                 struct dma_async_tx_descriptor *tx)
1702 {
1703         struct page **blocks = to_addr_page(percpu, 0);
1704         int count;
1705         struct async_submit_ctl submit;
1706
1707         pr_debug("%s: stripe %llu\n", __func__,
1708                 (unsigned long long)sh->sector);
1709
1710         count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_WANT_DRAIN);
1711
1712         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_PQ_XOR_DST, tx,
1713                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1714         tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
1715
1716         return tx;
1717 }
1718
1719 static struct dma_async_tx_descriptor *
1720 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1721 {
1722         struct r5conf *conf = sh->raid_conf;
1723         int disks = sh->disks;
1724         int i;
1725         struct stripe_head *head_sh = sh;
1726
1727         pr_debug("%s: stripe %llu\n", __func__,
1728                 (unsigned long long)sh->sector);
1729
1730         for (i = disks; i--; ) {
1731                 struct r5dev *dev;
1732                 struct bio *chosen;
1733
1734                 sh = head_sh;
1735                 if (test_and_clear_bit(R5_Wantdrain, &head_sh->dev[i].flags)) {
1736                         struct bio *wbi;
1737
1738 again:
1739                         dev = &sh->dev[i];
1740                         /*
1741                          * clear R5_InJournal, so when rewriting a page in
1742                          * journal, it is not skipped by r5l_log_stripe()
1743                          */
1744                         clear_bit(R5_InJournal, &dev->flags);
1745                         spin_lock_irq(&sh->stripe_lock);
1746                         chosen = dev->towrite;
1747                         dev->towrite = NULL;
1748                         sh->overwrite_disks = 0;
1749                         BUG_ON(dev->written);
1750                         wbi = dev->written = chosen;
1751                         spin_unlock_irq(&sh->stripe_lock);
1752                         WARN_ON(dev->page != dev->orig_page);
1753
1754                         while (wbi && wbi->bi_iter.bi_sector <
1755                                 dev->sector + STRIPE_SECTORS) {
1756                                 if (wbi->bi_opf & REQ_FUA)
1757                                         set_bit(R5_WantFUA, &dev->flags);
1758                                 if (wbi->bi_opf & REQ_SYNC)
1759                                         set_bit(R5_SyncIO, &dev->flags);
1760                                 if (bio_op(wbi) == REQ_OP_DISCARD)
1761                                         set_bit(R5_Discard, &dev->flags);
1762                                 else {
1763                                         tx = async_copy_data(1, wbi, &dev->page,
1764                                                              dev->sector, tx, sh,
1765                                                              r5c_is_writeback(conf->log));
1766                                         if (dev->page != dev->orig_page &&
1767                                             !r5c_is_writeback(conf->log)) {
1768                                                 set_bit(R5_SkipCopy, &dev->flags);
1769                                                 clear_bit(R5_UPTODATE, &dev->flags);
1770                                                 clear_bit(R5_OVERWRITE, &dev->flags);
1771                                         }
1772                                 }
1773                                 wbi = r5_next_bio(wbi, dev->sector);
1774                         }
1775
1776                         if (head_sh->batch_head) {
1777                                 sh = list_first_entry(&sh->batch_list,
1778                                                       struct stripe_head,
1779                                                       batch_list);
1780                                 if (sh == head_sh)
1781                                         continue;
1782                                 goto again;
1783                         }
1784                 }
1785         }
1786
1787         return tx;
1788 }
1789
1790 static void ops_complete_reconstruct(void *stripe_head_ref)
1791 {
1792         struct stripe_head *sh = stripe_head_ref;
1793         int disks = sh->disks;
1794         int pd_idx = sh->pd_idx;
1795         int qd_idx = sh->qd_idx;
1796         int i;
1797         bool fua = false, sync = false, discard = false;
1798
1799         pr_debug("%s: stripe %llu\n", __func__,
1800                 (unsigned long long)sh->sector);
1801
1802         for (i = disks; i--; ) {
1803                 fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
1804                 sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
1805                 discard |= test_bit(R5_Discard, &sh->dev[i].flags);
1806         }
1807
1808         for (i = disks; i--; ) {
1809                 struct r5dev *dev = &sh->dev[i];
1810
1811                 if (dev->written || i == pd_idx || i == qd_idx) {
1812                         if (!discard && !test_bit(R5_SkipCopy, &dev->flags)) {
1813                                 set_bit(R5_UPTODATE, &dev->flags);
1814                                 if (test_bit(STRIPE_EXPAND_READY, &sh->state))
1815                                         set_bit(R5_Expanded, &dev->flags);
1816                         }
1817                         if (fua)
1818                                 set_bit(R5_WantFUA, &dev->flags);
1819                         if (sync)
1820                                 set_bit(R5_SyncIO, &dev->flags);
1821                 }
1822         }
1823
1824         if (sh->reconstruct_state == reconstruct_state_drain_run)
1825                 sh->reconstruct_state = reconstruct_state_drain_result;
1826         else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
1827                 sh->reconstruct_state = reconstruct_state_prexor_drain_result;
1828         else {
1829                 BUG_ON(sh->reconstruct_state != reconstruct_state_run);
1830                 sh->reconstruct_state = reconstruct_state_result;
1831         }
1832
1833         set_bit(STRIPE_HANDLE, &sh->state);
1834         raid5_release_stripe(sh);
1835 }
1836
1837 static void
1838 ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
1839                      struct dma_async_tx_descriptor *tx)
1840 {
1841         int disks = sh->disks;
1842         struct page **xor_srcs;
1843         struct async_submit_ctl submit;
1844         int count, pd_idx = sh->pd_idx, i;
1845         struct page *xor_dest;
1846         int prexor = 0;
1847         unsigned long flags;
1848         int j = 0;
1849         struct stripe_head *head_sh = sh;
1850         int last_stripe;
1851
1852         pr_debug("%s: stripe %llu\n", __func__,
1853                 (unsigned long long)sh->sector);
1854
1855         for (i = 0; i < sh->disks; i++) {
1856                 if (pd_idx == i)
1857                         continue;
1858                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
1859                         break;
1860         }
1861         if (i >= sh->disks) {
1862                 atomic_inc(&sh->count);
1863                 set_bit(R5_Discard, &sh->dev[pd_idx].flags);
1864                 ops_complete_reconstruct(sh);
1865                 return;
1866         }
1867 again:
1868         count = 0;
1869         xor_srcs = to_addr_page(percpu, j);
1870         /* check if prexor is active which means only process blocks
1871          * that are part of a read-modify-write (written)
1872          */
1873         if (head_sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1874                 prexor = 1;
1875                 xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1876                 for (i = disks; i--; ) {
1877                         struct r5dev *dev = &sh->dev[i];
1878                         if (head_sh->dev[i].written ||
1879                             test_bit(R5_InJournal, &head_sh->dev[i].flags))
1880                                 xor_srcs[count++] = dev->page;
1881                 }
1882         } else {
1883                 xor_dest = sh->dev[pd_idx].page;
1884                 for (i = disks; i--; ) {
1885                         struct r5dev *dev = &sh->dev[i];
1886                         if (i != pd_idx)
1887                                 xor_srcs[count++] = dev->page;
1888                 }
1889         }
1890
1891         /* 1/ if we prexor'd then the dest is reused as a source
1892          * 2/ if we did not prexor then we are redoing the parity
1893          * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
1894          * for the synchronous xor case
1895          */
1896         last_stripe = !head_sh->batch_head ||
1897                 list_first_entry(&sh->batch_list,
1898                                  struct stripe_head, batch_list) == head_sh;
1899         if (last_stripe) {
1900                 flags = ASYNC_TX_ACK |
1901                         (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
1902
1903                 atomic_inc(&head_sh->count);
1904                 init_async_submit(&submit, flags, tx, ops_complete_reconstruct, head_sh,
1905                                   to_addr_conv(sh, percpu, j));
1906         } else {
1907                 flags = prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST;
1908                 init_async_submit(&submit, flags, tx, NULL, NULL,
1909                                   to_addr_conv(sh, percpu, j));
1910         }
1911
1912         if (unlikely(count == 1))
1913                 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
1914         else
1915                 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1916         if (!last_stripe) {
1917                 j++;
1918                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1919                                       batch_list);
1920                 goto again;
1921         }
1922 }
1923
1924 static void
1925 ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
1926                      struct dma_async_tx_descriptor *tx)
1927 {
1928         struct async_submit_ctl submit;
1929         struct page **blocks;
1930         int count, i, j = 0;
1931         struct stripe_head *head_sh = sh;
1932         int last_stripe;
1933         int synflags;
1934         unsigned long txflags;
1935
1936         pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
1937
1938         for (i = 0; i < sh->disks; i++) {
1939                 if (sh->pd_idx == i || sh->qd_idx == i)
1940                         continue;
1941                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
1942                         break;
1943         }
1944         if (i >= sh->disks) {
1945                 atomic_inc(&sh->count);
1946                 set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
1947                 set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
1948                 ops_complete_reconstruct(sh);
1949                 return;
1950         }
1951
1952 again:
1953         blocks = to_addr_page(percpu, j);
1954
1955         if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1956                 synflags = SYNDROME_SRC_WRITTEN;
1957                 txflags = ASYNC_TX_ACK | ASYNC_TX_PQ_XOR_DST;
1958         } else {
1959                 synflags = SYNDROME_SRC_ALL;
1960                 txflags = ASYNC_TX_ACK;
1961         }
1962
1963         count = set_syndrome_sources(blocks, sh, synflags);
1964         last_stripe = !head_sh->batch_head ||
1965                 list_first_entry(&sh->batch_list,
1966                                  struct stripe_head, batch_list) == head_sh;
1967
1968         if (last_stripe) {
1969                 atomic_inc(&head_sh->count);
1970                 init_async_submit(&submit, txflags, tx, ops_complete_reconstruct,
1971                                   head_sh, to_addr_conv(sh, percpu, j));
1972         } else
1973                 init_async_submit(&submit, 0, tx, NULL, NULL,
1974                                   to_addr_conv(sh, percpu, j));
1975         tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
1976         if (!last_stripe) {
1977                 j++;
1978                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1979                                       batch_list);
1980                 goto again;
1981         }
1982 }
1983
1984 static void ops_complete_check(void *stripe_head_ref)
1985 {
1986         struct stripe_head *sh = stripe_head_ref;
1987
1988         pr_debug("%s: stripe %llu\n", __func__,
1989                 (unsigned long long)sh->sector);
1990
1991         sh->check_state = check_state_check_result;
1992         set_bit(STRIPE_HANDLE, &sh->state);
1993         raid5_release_stripe(sh);
1994 }
1995
1996 static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
1997 {
1998         int disks = sh->disks;
1999         int pd_idx = sh->pd_idx;
2000         int qd_idx = sh->qd_idx;
2001         struct page *xor_dest;
2002         struct page **xor_srcs = to_addr_page(percpu, 0);
2003         struct dma_async_tx_descriptor *tx;
2004         struct async_submit_ctl submit;
2005         int count;
2006         int i;
2007
2008         pr_debug("%s: stripe %llu\n", __func__,
2009                 (unsigned long long)sh->sector);
2010
2011         BUG_ON(sh->batch_head);
2012         count = 0;
2013         xor_dest = sh->dev[pd_idx].page;
2014         xor_srcs[count++] = xor_dest;
2015         for (i = disks; i--; ) {
2016                 if (i == pd_idx || i == qd_idx)
2017                         continue;
2018                 xor_srcs[count++] = sh->dev[i].page;
2019         }
2020
2021         init_async_submit(&submit, 0, NULL, NULL, NULL,
2022                           to_addr_conv(sh, percpu, 0));
2023         tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
2024                            &sh->ops.zero_sum_result, &submit);
2025
2026         atomic_inc(&sh->count);
2027         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
2028         tx = async_trigger_callback(&submit);
2029 }
2030
2031 static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
2032 {
2033         struct page **srcs = to_addr_page(percpu, 0);
2034         struct async_submit_ctl submit;
2035         int count;
2036
2037         pr_debug("%s: stripe %llu checkp: %d\n", __func__,
2038                 (unsigned long long)sh->sector, checkp);
2039
2040         BUG_ON(sh->batch_head);
2041         count = set_syndrome_sources(srcs, sh, SYNDROME_SRC_ALL);
2042         if (!checkp)
2043                 srcs[count] = NULL;
2044
2045         atomic_inc(&sh->count);
2046         init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
2047                           sh, to_addr_conv(sh, percpu, 0));
2048         async_syndrome_val(srcs, 0, count+2, STRIPE_SIZE,
2049                            &sh->ops.zero_sum_result, percpu->spare_page, &submit);
2050 }
2051
2052 static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
2053 {
2054         int overlap_clear = 0, i, disks = sh->disks;
2055         struct dma_async_tx_descriptor *tx = NULL;
2056         struct r5conf *conf = sh->raid_conf;
2057         int level = conf->level;
2058         struct raid5_percpu *percpu;
2059         unsigned long cpu;
2060
2061         cpu = get_cpu();
2062         percpu = per_cpu_ptr(conf->percpu, cpu);
2063         if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
2064                 ops_run_biofill(sh);
2065                 overlap_clear++;
2066         }
2067
2068         if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
2069                 if (level < 6)
2070                         tx = ops_run_compute5(sh, percpu);
2071                 else {
2072                         if (sh->ops.target2 < 0 || sh->ops.target < 0)
2073                                 tx = ops_run_compute6_1(sh, percpu);
2074                         else
2075                                 tx = ops_run_compute6_2(sh, percpu);
2076                 }
2077                 /* terminate the chain if reconstruct is not set to be run */
2078                 if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
2079                         async_tx_ack(tx);
2080         }
2081
2082         if (test_bit(STRIPE_OP_PREXOR, &ops_request)) {
2083                 if (level < 6)
2084                         tx = ops_run_prexor5(sh, percpu, tx);
2085                 else
2086                         tx = ops_run_prexor6(sh, percpu, tx);
2087         }
2088
2089         if (test_bit(STRIPE_OP_PARTIAL_PARITY, &ops_request))
2090                 tx = ops_run_partial_parity(sh, percpu, tx);
2091
2092         if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
2093                 tx = ops_run_biodrain(sh, tx);
2094                 overlap_clear++;
2095         }
2096
2097         if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
2098                 if (level < 6)
2099                         ops_run_reconstruct5(sh, percpu, tx);
2100                 else
2101                         ops_run_reconstruct6(sh, percpu, tx);
2102         }
2103
2104         if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
2105                 if (sh->check_state == check_state_run)
2106                         ops_run_check_p(sh, percpu);
2107                 else if (sh->check_state == check_state_run_q)
2108                         ops_run_check_pq(sh, percpu, 0);
2109                 else if (sh->check_state == check_state_run_pq)
2110                         ops_run_check_pq(sh, percpu, 1);
2111                 else
2112                         BUG();
2113         }
2114
2115         if (overlap_clear && !sh->batch_head)
2116                 for (i = disks; i--; ) {
2117                         struct r5dev *dev = &sh->dev[i];
2118                         if (test_and_clear_bit(R5_Overlap, &dev->flags))
2119                                 wake_up(&sh->raid_conf->wait_for_overlap);
2120                 }
2121         put_cpu();
2122 }
2123
2124 static void free_stripe(struct kmem_cache *sc, struct stripe_head *sh)
2125 {
2126         if (sh->ppl_page)
2127                 __free_page(sh->ppl_page);
2128         kmem_cache_free(sc, sh);
2129 }
2130
2131 static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp,
2132         int disks, struct r5conf *conf)
2133 {
2134         struct stripe_head *sh;
2135         int i;
2136
2137         sh = kmem_cache_zalloc(sc, gfp);
2138         if (sh) {
2139                 spin_lock_init(&sh->stripe_lock);
2140                 spin_lock_init(&sh->batch_lock);
2141                 INIT_LIST_HEAD(&sh->batch_list);
2142                 INIT_LIST_HEAD(&sh->lru);
2143                 INIT_LIST_HEAD(&sh->r5c);
2144                 INIT_LIST_HEAD(&sh->log_list);
2145                 atomic_set(&sh->count, 1);
2146                 sh->raid_conf = conf;
2147                 sh->log_start = MaxSector;
2148                 for (i = 0; i < disks; i++) {
2149                         struct r5dev *dev = &sh->dev[i];
2150
2151                         bio_init(&dev->req, &dev->vec, 1);
2152                         bio_init(&dev->rreq, &dev->rvec, 1);
2153                 }
2154
2155                 if (raid5_has_ppl(conf)) {
2156                         sh->ppl_page = alloc_page(gfp);
2157                         if (!sh->ppl_page) {
2158                                 free_stripe(sc, sh);
2159                                 sh = NULL;
2160                         }
2161                 }
2162         }
2163         return sh;
2164 }
2165 static int grow_one_stripe(struct r5conf *conf, gfp_t gfp)
2166 {
2167         struct stripe_head *sh;
2168
2169         sh = alloc_stripe(conf->slab_cache, gfp, conf->pool_size, conf);
2170         if (!sh)
2171                 return 0;
2172
2173         if (grow_buffers(sh, gfp)) {
2174                 shrink_buffers(sh);
2175                 free_stripe(conf->slab_cache, sh);
2176                 return 0;
2177         }
2178         sh->hash_lock_index =
2179                 conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS;
2180         /* we just created an active stripe so... */
2181         atomic_inc(&conf->active_stripes);
2182
2183         raid5_release_stripe(sh);
2184         conf->max_nr_stripes++;
2185         return 1;
2186 }
2187
2188 static int grow_stripes(struct r5conf *conf, int num)
2189 {
2190         struct kmem_cache *sc;
2191         size_t namelen = sizeof(conf->cache_name[0]);
2192         int devs = max(conf->raid_disks, conf->previous_raid_disks);
2193
2194         if (conf->mddev->gendisk)
2195                 snprintf(conf->cache_name[0], namelen,
2196                         "raid%d-%s", conf->level, mdname(conf->mddev));
2197         else
2198                 snprintf(conf->cache_name[0], namelen,
2199                         "raid%d-%p", conf->level, conf->mddev);
2200         snprintf(conf->cache_name[1], namelen, "%.27s-alt", conf->cache_name[0]);
2201
2202         conf->active_name = 0;
2203         sc = kmem_cache_create(conf->cache_name[conf->active_name],
2204                                sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
2205                                0, 0, NULL);
2206         if (!sc)
2207                 return 1;
2208         conf->slab_cache = sc;
2209         conf->pool_size = devs;
2210         while (num--)
2211                 if (!grow_one_stripe(conf, GFP_KERNEL))
2212                         return 1;
2213
2214         return 0;
2215 }
2216
2217 /**
2218  * scribble_len - return the required size of the scribble region
2219  * @num - total number of disks in the array
2220  *
2221  * The size must be enough to contain:
2222  * 1/ a struct page pointer for each device in the array +2
2223  * 2/ room to convert each entry in (1) to its corresponding dma
2224  *    (dma_map_page()) or page (page_address()) address.
2225  *
2226  * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
2227  * calculate over all devices (not just the data blocks), using zeros in place
2228  * of the P and Q blocks.
2229  */
2230 static int scribble_alloc(struct raid5_percpu *percpu,
2231                           int num, int cnt, gfp_t flags)
2232 {
2233         size_t obj_size =
2234                 sizeof(struct page *) * (num+2) +
2235                 sizeof(addr_conv_t) * (num+2);
2236         void *scribble;
2237
2238         scribble = kvmalloc_array(cnt, obj_size, flags);
2239         if (!scribble)
2240                 return -ENOMEM;
2241
2242         kvfree(percpu->scribble);
2243
2244         percpu->scribble = scribble;
2245         percpu->scribble_obj_size = obj_size;
2246         return 0;
2247 }
2248
2249 static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
2250 {
2251         unsigned long cpu;
2252         int err = 0;
2253
2254         /*
2255          * Never shrink. And mddev_suspend() could deadlock if this is called
2256          * from raid5d. In that case, scribble_disks and scribble_sectors
2257          * should equal to new_disks and new_sectors
2258          */
2259         if (conf->scribble_disks >= new_disks &&
2260             conf->scribble_sectors >= new_sectors)
2261                 return 0;
2262         mddev_suspend(conf->mddev);
2263         get_online_cpus();
2264
2265         for_each_present_cpu(cpu) {
2266                 struct raid5_percpu *percpu;
2267
2268                 percpu = per_cpu_ptr(conf->percpu, cpu);
2269                 err = scribble_alloc(percpu, new_disks,
2270                                      new_sectors / STRIPE_SECTORS,
2271                                      GFP_NOIO);
2272                 if (err)
2273                         break;
2274         }
2275
2276         put_online_cpus();
2277         mddev_resume(conf->mddev);
2278         if (!err) {
2279                 conf->scribble_disks = new_disks;
2280                 conf->scribble_sectors = new_sectors;
2281         }
2282         return err;
2283 }
2284
2285 static int resize_stripes(struct r5conf *conf, int newsize)
2286 {
2287         /* Make all the stripes able to hold 'newsize' devices.
2288          * New slots in each stripe get 'page' set to a new page.
2289          *
2290          * This happens in stages:
2291          * 1/ create a new kmem_cache and allocate the required number of
2292          *    stripe_heads.
2293          * 2/ gather all the old stripe_heads and transfer the pages across
2294          *    to the new stripe_heads.  This will have the side effect of
2295          *    freezing the array as once all stripe_heads have been collected,
2296          *    no IO will be possible.  Old stripe heads are freed once their
2297          *    pages have been transferred over, and the old kmem_cache is
2298          *    freed when all stripes are done.
2299          * 3/ reallocate conf->disks to be suitable bigger.  If this fails,
2300          *    we simple return a failure status - no need to clean anything up.
2301          * 4/ allocate new pages for the new slots in the new stripe_heads.
2302          *    If this fails, we don't bother trying the shrink the
2303          *    stripe_heads down again, we just leave them as they are.
2304          *    As each stripe_head is processed the new one is released into
2305          *    active service.
2306          *
2307          * Once step2 is started, we cannot afford to wait for a write,
2308          * so we use GFP_NOIO allocations.
2309          */
2310         struct stripe_head *osh, *nsh;
2311         LIST_HEAD(newstripes);
2312         struct disk_info *ndisks;
2313         int err = 0;
2314         struct kmem_cache *sc;
2315         int i;
2316         int hash, cnt;
2317
2318         md_allow_write(conf->mddev);
2319
2320         /* Step 1 */
2321         sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
2322                                sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
2323                                0, 0, NULL);
2324         if (!sc)
2325                 return -ENOMEM;
2326
2327         /* Need to ensure auto-resizing doesn't interfere */
2328         mutex_lock(&conf->cache_size_mutex);
2329
2330         for (i = conf->max_nr_stripes; i; i--) {
2331                 nsh = alloc_stripe(sc, GFP_KERNEL, newsize, conf);
2332                 if (!nsh)
2333                         break;
2334
2335                 list_add(&nsh->lru, &newstripes);
2336         }
2337         if (i) {
2338                 /* didn't get enough, give up */
2339                 while (!list_empty(&newstripes)) {
2340                         nsh = list_entry(newstripes.next, struct stripe_head, lru);
2341                         list_del(&nsh->lru);
2342                         free_stripe(sc, nsh);
2343                 }
2344                 kmem_cache_destroy(sc);
2345                 mutex_unlock(&conf->cache_size_mutex);
2346                 return -ENOMEM;
2347         }
2348         /* Step 2 - Must use GFP_NOIO now.
2349          * OK, we have enough stripes, start collecting inactive
2350          * stripes and copying them over
2351          */
2352         hash = 0;
2353         cnt = 0;
2354         list_for_each_entry(nsh, &newstripes, lru) {
2355                 lock_device_hash_lock(conf, hash);
2356                 wait_event_cmd(conf->wait_for_stripe,
2357                                     !list_empty(conf->inactive_list + hash),
2358                                     unlock_device_hash_lock(conf, hash),
2359                                     lock_device_hash_lock(conf, hash));
2360                 osh = get_free_stripe(conf, hash);
2361                 unlock_device_hash_lock(conf, hash);
2362
2363                 for(i=0; i<conf->pool_size; i++) {
2364                         nsh->dev[i].page = osh->dev[i].page;
2365                         nsh->dev[i].orig_page = osh->dev[i].page;
2366                 }
2367                 nsh->hash_lock_index = hash;
2368                 free_stripe(conf->slab_cache, osh);
2369                 cnt++;
2370                 if (cnt >= conf->max_nr_stripes / NR_STRIPE_HASH_LOCKS +
2371                     !!((conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS) > hash)) {
2372                         hash++;
2373                         cnt = 0;
2374                 }
2375         }
2376         kmem_cache_destroy(conf->slab_cache);
2377
2378         /* Step 3.
2379          * At this point, we are holding all the stripes so the array
2380          * is completely stalled, so now is a good time to resize
2381          * conf->disks and the scribble region
2382          */
2383         ndisks = kcalloc(newsize, sizeof(struct disk_info), GFP_NOIO);
2384         if (ndisks) {
2385                 for (i = 0; i < conf->pool_size; i++)
2386                         ndisks[i] = conf->disks[i];
2387
2388                 for (i = conf->pool_size; i < newsize; i++) {
2389                         ndisks[i].extra_page = alloc_page(GFP_NOIO);
2390                         if (!ndisks[i].extra_page)
2391                                 err = -ENOMEM;
2392                 }
2393
2394                 if (err) {
2395                         for (i = conf->pool_size; i < newsize; i++)
2396                                 if (ndisks[i].extra_page)
2397                                         put_page(ndisks[i].extra_page);
2398                         kfree(ndisks);
2399                 } else {
2400                         kfree(conf->disks);
2401                         conf->disks = ndisks;
2402                 }
2403         } else
2404                 err = -ENOMEM;
2405
2406         mutex_unlock(&conf->cache_size_mutex);
2407
2408         conf->slab_cache = sc;
2409         conf->active_name = 1-conf->active_name;
2410
2411         /* Step 4, return new stripes to service */
2412         while(!list_empty(&newstripes)) {
2413                 nsh = list_entry(newstripes.next, struct stripe_head, lru);
2414                 list_del_init(&nsh->lru);
2415
2416                 for (i=conf->raid_disks; i < newsize; i++)
2417                         if (nsh->dev[i].page == NULL) {
2418                                 struct page *p = alloc_page(GFP_NOIO);
2419                                 nsh->dev[i].page = p;
2420                                 nsh->dev[i].orig_page = p;
2421                                 if (!p)
2422                                         err = -ENOMEM;
2423                         }
2424                 raid5_release_stripe(nsh);
2425         }
2426         /* critical section pass, GFP_NOIO no longer needed */
2427
2428         if (!err)
2429                 conf->pool_size = newsize;
2430         return err;
2431 }
2432
2433 static int drop_one_stripe(struct r5conf *conf)
2434 {
2435         struct stripe_head *sh;
2436         int hash = (conf->max_nr_stripes - 1) & STRIPE_HASH_LOCKS_MASK;
2437
2438         spin_lock_irq(conf->hash_locks + hash);
2439         sh = get_free_stripe(conf, hash);
2440         spin_unlock_irq(conf->hash_locks + hash);
2441         if (!sh)
2442                 return 0;
2443         BUG_ON(atomic_read(&sh->count));
2444         shrink_buffers(sh);
2445         free_stripe(conf->slab_cache, sh);
2446         atomic_dec(&conf->active_stripes);
2447         conf->max_nr_stripes--;
2448         return 1;
2449 }
2450
2451 static void shrink_stripes(struct r5conf *conf)
2452 {
2453         while (conf->max_nr_stripes &&
2454                drop_one_stripe(conf))
2455                 ;
2456
2457         kmem_cache_destroy(conf->slab_cache);
2458         conf->slab_cache = NULL;
2459 }
2460
2461 static void raid5_end_read_request(struct bio * bi)
2462 {
2463         struct stripe_head *sh = bi->bi_private;
2464         struct r5conf *conf = sh->raid_conf;
2465         int disks = sh->disks, i;
2466         char b[BDEVNAME_SIZE];
2467         struct md_rdev *rdev = NULL;
2468         sector_t s;
2469
2470         for (i=0 ; i<disks; i++)
2471                 if (bi == &sh->dev[i].req)
2472                         break;
2473
2474         pr_debug("end_read_request %llu/%d, count: %d, error %d.\n",
2475                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2476                 bi->bi_status);
2477         if (i == disks) {
2478                 bio_reset(bi);
2479                 BUG();
2480                 return;
2481         }
2482         if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2483                 /* If replacement finished while this request was outstanding,
2484                  * 'replacement' might be NULL already.
2485                  * In that case it moved down to 'rdev'.
2486                  * rdev is not removed until all requests are finished.
2487                  */
2488                 rdev = conf->disks[i].replacement;
2489         if (!rdev)
2490                 rdev = conf->disks[i].rdev;
2491
2492         if (use_new_offset(conf, sh))
2493                 s = sh->sector + rdev->new_data_offset;
2494         else
2495                 s = sh->sector + rdev->data_offset;
2496         if (!bi->bi_status) {
2497                 set_bit(R5_UPTODATE, &sh->dev[i].flags);
2498                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2499                         /* Note that this cannot happen on a
2500                          * replacement device.  We just fail those on
2501                          * any error
2502                          */
2503                         pr_info_ratelimited(
2504                                 "md/raid:%s: read error corrected (%lu sectors at %llu on %s)\n",
2505                                 mdname(conf->mddev), STRIPE_SECTORS,
2506                                 (unsigned long long)s,
2507                                 bdevname(rdev->bdev, b));
2508                         atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
2509                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2510                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2511                 } else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2512                         clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2513
2514                 if (test_bit(R5_InJournal, &sh->dev[i].flags))
2515                         /*
2516                          * end read for a page in journal, this
2517                          * must be preparing for prexor in rmw
2518                          */
2519                         set_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags);
2520
2521                 if (atomic_read(&rdev->read_errors))
2522                         atomic_set(&rdev->read_errors, 0);
2523         } else {
2524                 const char *bdn = bdevname(rdev->bdev, b);
2525                 int retry = 0;
2526                 int set_bad = 0;
2527
2528                 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
2529                 if (!(bi->bi_status == BLK_STS_PROTECTION))
2530                         atomic_inc(&rdev->read_errors);
2531                 if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2532                         pr_warn_ratelimited(
2533                                 "md/raid:%s: read error on replacement device (sector %llu on %s).\n",
2534                                 mdname(conf->mddev),
2535                                 (unsigned long long)s,
2536                                 bdn);
2537                 else if (conf->mddev->degraded >= conf->max_degraded) {
2538                         set_bad = 1;
2539                         pr_warn_ratelimited(
2540                                 "md/raid:%s: read error not correctable (sector %llu on %s).\n",
2541                                 mdname(conf->mddev),
2542                                 (unsigned long long)s,
2543                                 bdn);
2544                 } else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
2545                         /* Oh, no!!! */
2546                         set_bad = 1;
2547                         pr_warn_ratelimited(
2548                                 "md/raid:%s: read error NOT corrected!! (sector %llu on %s).\n",
2549                                 mdname(conf->mddev),
2550                                 (unsigned long long)s,
2551                                 bdn);
2552                 } else if (atomic_read(&rdev->read_errors)
2553                          > conf->max_nr_stripes) {
2554                         if (!test_bit(Faulty, &rdev->flags)) {
2555                                 pr_warn("md/raid:%s: %d read_errors > %d stripes\n",
2556                                     mdname(conf->mddev),
2557                                     atomic_read(&rdev->read_errors),
2558                                     conf->max_nr_stripes);
2559                                 pr_warn("md/raid:%s: Too many read errors, failing device %s.\n",
2560                                     mdname(conf->mddev), bdn);
2561                         }
2562                 } else
2563                         retry = 1;
2564                 if (set_bad && test_bit(In_sync, &rdev->flags)
2565                     && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2566                         retry = 1;
2567                 if (retry)
2568                         if (sh->qd_idx >= 0 && sh->pd_idx == i)
2569                                 set_bit(R5_ReadError, &sh->dev[i].flags);
2570                         else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
2571                                 set_bit(R5_ReadError, &sh->dev[i].flags);
2572                                 clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2573                         } else
2574                                 set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2575                 else {
2576                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2577                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2578                         if (!(set_bad
2579                               && test_bit(In_sync, &rdev->flags)
2580                               && rdev_set_badblocks(
2581                                       rdev, sh->sector, STRIPE_SECTORS, 0)))
2582                                 md_error(conf->mddev, rdev);
2583                 }
2584         }
2585         rdev_dec_pending(rdev, conf->mddev);
2586         bio_reset(bi);
2587         clear_bit(R5_LOCKED, &sh->dev[i].flags);
2588         set_bit(STRIPE_HANDLE, &sh->state);
2589         raid5_release_stripe(sh);
2590 }
2591
2592 static void raid5_end_write_request(struct bio *bi)
2593 {
2594         struct stripe_head *sh = bi->bi_private;
2595         struct r5conf *conf = sh->raid_conf;
2596         int disks = sh->disks, i;
2597         struct md_rdev *uninitialized_var(rdev);
2598         sector_t first_bad;
2599         int bad_sectors;
2600         int replacement = 0;
2601
2602         for (i = 0 ; i < disks; i++) {
2603                 if (bi == &sh->dev[i].req) {
2604                         rdev = conf->disks[i].rdev;
2605                         break;
2606                 }
2607                 if (bi == &sh->dev[i].rreq) {
2608                         rdev = conf->disks[i].replacement;
2609                         if (rdev)
2610                                 replacement = 1;
2611                         else
2612                                 /* rdev was removed and 'replacement'
2613                                  * replaced it.  rdev is not removed
2614                                  * until all requests are finished.
2615                                  */
2616                                 rdev = conf->disks[i].rdev;
2617                         break;
2618                 }
2619         }
2620         pr_debug("end_write_request %llu/%d, count %d, error: %d.\n",
2621                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2622                 bi->bi_status);
2623         if (i == disks) {
2624                 bio_reset(bi);
2625                 BUG();
2626                 return;
2627         }
2628
2629         if (replacement) {
2630                 if (bi->bi_status)
2631                         md_error(conf->mddev, rdev);
2632                 else if (is_badblock(rdev, sh->sector,
2633                                      STRIPE_SECTORS,
2634                                      &first_bad, &bad_sectors))
2635                         set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
2636         } else {
2637                 if (bi->bi_status) {
2638                         set_bit(STRIPE_DEGRADED, &sh->state);
2639                         set_bit(WriteErrorSeen, &rdev->flags);
2640                         set_bit(R5_WriteError, &sh->dev[i].flags);
2641                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
2642                                 set_bit(MD_RECOVERY_NEEDED,
2643                                         &rdev->mddev->recovery);
2644                 } else if (is_badblock(rdev, sh->sector,
2645                                        STRIPE_SECTORS,
2646                                        &first_bad, &bad_sectors)) {
2647                         set_bit(R5_MadeGood, &sh->dev[i].flags);
2648                         if (test_bit(R5_ReadError, &sh->dev[i].flags))
2649                                 /* That was a successful write so make
2650                                  * sure it looks like we already did
2651                                  * a re-write.
2652                                  */
2653                                 set_bit(R5_ReWrite, &sh->dev[i].flags);
2654                 }
2655         }
2656         rdev_dec_pending(rdev, conf->mddev);
2657
2658         if (sh->batch_head && bi->bi_status && !replacement)
2659                 set_bit(STRIPE_BATCH_ERR, &sh->batch_head->state);
2660
2661         bio_reset(bi);
2662         if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
2663                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
2664         set_bit(STRIPE_HANDLE, &sh->state);
2665         raid5_release_stripe(sh);
2666
2667         if (sh->batch_head && sh != sh->batch_head)
2668                 raid5_release_stripe(sh->batch_head);
2669 }
2670
2671 static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
2672 {
2673         char b[BDEVNAME_SIZE];
2674         struct r5conf *conf = mddev->private;
2675         unsigned long flags;
2676         pr_debug("raid456: error called\n");
2677
2678         spin_lock_irqsave(&conf->device_lock, flags);
2679
2680         if (test_bit(In_sync, &rdev->flags) &&
2681             mddev->degraded == conf->max_degraded) {
2682                 /*
2683                  * Don't allow to achieve failed state
2684                  * Don't try to recover this device
2685                  */
2686                 conf->recovery_disabled = mddev->recovery_disabled;
2687                 spin_unlock_irqrestore(&conf->device_lock, flags);
2688                 return;
2689         }
2690
2691         set_bit(Faulty, &rdev->flags);
2692         clear_bit(In_sync, &rdev->flags);
2693         mddev->degraded = raid5_calc_degraded(conf);
2694         spin_unlock_irqrestore(&conf->device_lock, flags);
2695         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2696
2697         set_bit(Blocked, &rdev->flags);
2698         set_mask_bits(&mddev->sb_flags, 0,
2699                       BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
2700         pr_crit("md/raid:%s: Disk failure on %s, disabling device.\n"
2701                 "md/raid:%s: Operation continuing on %d devices.\n",
2702                 mdname(mddev),
2703                 bdevname(rdev->bdev, b),
2704                 mdname(mddev),
2705                 conf->raid_disks - mddev->degraded);
2706         r5c_update_on_rdev_error(mddev, rdev);
2707 }
2708
2709 /*
2710  * Input: a 'big' sector number,
2711  * Output: index of the data and parity disk, and the sector # in them.
2712  */
2713 sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
2714                               int previous, int *dd_idx,
2715                               struct stripe_head *sh)
2716 {
2717         sector_t stripe, stripe2;
2718         sector_t chunk_number;
2719         unsigned int chunk_offset;
2720         int pd_idx, qd_idx;
2721         int ddf_layout = 0;
2722         sector_t new_sector;
2723         int algorithm = previous ? conf->prev_algo
2724                                  : conf->algorithm;
2725         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2726                                          : conf->chunk_sectors;
2727         int raid_disks = previous ? conf->previous_raid_disks
2728                                   : conf->raid_disks;
2729         int data_disks = raid_disks - conf->max_degraded;
2730
2731         /* First compute the information on this sector */
2732
2733         /*
2734          * Compute the chunk number and the sector offset inside the chunk
2735          */
2736         chunk_offset = sector_div(r_sector, sectors_per_chunk);
2737         chunk_number = r_sector;
2738
2739         /*
2740          * Compute the stripe number
2741          */
2742         stripe = chunk_number;
2743         *dd_idx = sector_div(stripe, data_disks);
2744         stripe2 = stripe;
2745         /*
2746          * Select the parity disk based on the user selected algorithm.
2747          */
2748         pd_idx = qd_idx = -1;
2749         switch(conf->level) {
2750         case 4:
2751                 pd_idx = data_disks;
2752                 break;
2753         case 5:
2754                 switch (algorithm) {
2755                 case ALGORITHM_LEFT_ASYMMETRIC:
2756                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
2757                         if (*dd_idx >= pd_idx)
2758                                 (*dd_idx)++;
2759                         break;
2760                 case ALGORITHM_RIGHT_ASYMMETRIC:
2761                         pd_idx = sector_div(stripe2, raid_disks);
2762                         if (*dd_idx >= pd_idx)
2763                                 (*dd_idx)++;
2764                         break;
2765                 case ALGORITHM_LEFT_SYMMETRIC:
2766                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
2767                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2768                         break;
2769                 case ALGORITHM_RIGHT_SYMMETRIC:
2770                         pd_idx = sector_div(stripe2, raid_disks);
2771                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2772                         break;
2773                 case ALGORITHM_PARITY_0:
2774                         pd_idx = 0;
2775                         (*dd_idx)++;
2776                         break;
2777                 case ALGORITHM_PARITY_N:
2778                         pd_idx = data_disks;
2779                         break;
2780                 default:
2781                         BUG();
2782                 }
2783                 break;
2784         case 6:
2785
2786                 switch (algorithm) {
2787                 case ALGORITHM_LEFT_ASYMMETRIC:
2788                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2789                         qd_idx = pd_idx + 1;
2790                         if (pd_idx == raid_disks-1) {
2791                                 (*dd_idx)++;    /* Q D D D P */
2792                                 qd_idx = 0;
2793                         } else if (*dd_idx >= pd_idx)
2794                                 (*dd_idx) += 2; /* D D P Q D */
2795                         break;
2796                 case ALGORITHM_RIGHT_ASYMMETRIC:
2797                         pd_idx = sector_div(stripe2, raid_disks);
2798                         qd_idx = pd_idx + 1;
2799                         if (pd_idx == raid_disks-1) {
2800                                 (*dd_idx)++;    /* Q D D D P */
2801                                 qd_idx = 0;
2802                         } else if (*dd_idx >= pd_idx)
2803                                 (*dd_idx) += 2; /* D D P Q D */
2804                         break;
2805                 case ALGORITHM_LEFT_SYMMETRIC:
2806                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2807                         qd_idx = (pd_idx + 1) % raid_disks;
2808                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2809                         break;
2810                 case ALGORITHM_RIGHT_SYMMETRIC:
2811                         pd_idx = sector_div(stripe2, raid_disks);
2812                         qd_idx = (pd_idx + 1) % raid_disks;
2813                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2814                         break;
2815
2816                 case ALGORITHM_PARITY_0:
2817                         pd_idx = 0;
2818                         qd_idx = 1;
2819                         (*dd_idx) += 2;
2820                         break;
2821                 case ALGORITHM_PARITY_N:
2822                         pd_idx = data_disks;
2823                         qd_idx = data_disks + 1;
2824                         break;
2825
2826                 case ALGORITHM_ROTATING_ZERO_RESTART:
2827                         /* Exactly the same as RIGHT_ASYMMETRIC, but or
2828                          * of blocks for computing Q is different.
2829                          */
2830                         pd_idx = sector_div(stripe2, raid_disks);
2831                         qd_idx = pd_idx + 1;
2832                         if (pd_idx == raid_disks-1) {
2833                                 (*dd_idx)++;    /* Q D D D P */
2834                                 qd_idx = 0;
2835                         } else if (*dd_idx >= pd_idx)
2836                                 (*dd_idx) += 2; /* D D P Q D */
2837                         ddf_layout = 1;
2838                         break;
2839
2840                 case ALGORITHM_ROTATING_N_RESTART:
2841                         /* Same a left_asymmetric, by first stripe is
2842                          * D D D P Q  rather than
2843                          * Q D D D P
2844                          */
2845                         stripe2 += 1;
2846                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2847                         qd_idx = pd_idx + 1;
2848                         if (pd_idx == raid_disks-1) {
2849                                 (*dd_idx)++;    /* Q D D D P */
2850                                 qd_idx = 0;
2851                         } else if (*dd_idx >= pd_idx)
2852                                 (*dd_idx) += 2; /* D D P Q D */
2853                         ddf_layout = 1;
2854                         break;
2855
2856                 case ALGORITHM_ROTATING_N_CONTINUE:
2857                         /* Same as left_symmetric but Q is before P */
2858                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2859                         qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
2860                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2861                         ddf_layout = 1;
2862                         break;
2863
2864                 case ALGORITHM_LEFT_ASYMMETRIC_6:
2865                         /* RAID5 left_asymmetric, with Q on last device */
2866                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2867                         if (*dd_idx >= pd_idx)
2868                                 (*dd_idx)++;
2869                         qd_idx = raid_disks - 1;
2870                         break;
2871
2872                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
2873                         pd_idx = sector_div(stripe2, raid_disks-1);
2874                         if (*dd_idx >= pd_idx)
2875                                 (*dd_idx)++;
2876                         qd_idx = raid_disks - 1;
2877                         break;
2878
2879                 case ALGORITHM_LEFT_SYMMETRIC_6:
2880                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2881                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2882                         qd_idx = raid_disks - 1;
2883                         break;
2884
2885                 case ALGORITHM_RIGHT_SYMMETRIC_6:
2886                         pd_idx = sector_div(stripe2, raid_disks-1);
2887                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2888                         qd_idx = raid_disks - 1;
2889                         break;
2890
2891                 case ALGORITHM_PARITY_0_6:
2892                         pd_idx = 0;
2893                         (*dd_idx)++;
2894                         qd_idx = raid_disks - 1;
2895                         break;
2896
2897                 default:
2898                         BUG();
2899                 }
2900                 break;
2901         }
2902
2903         if (sh) {
2904                 sh->pd_idx = pd_idx;
2905                 sh->qd_idx = qd_idx;
2906                 sh->ddf_layout = ddf_layout;
2907         }
2908         /*
2909          * Finally, compute the new sector number
2910          */
2911         new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
2912         return new_sector;
2913 }
2914
2915 sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous)
2916 {
2917         struct r5conf *conf = sh->raid_conf;
2918         int raid_disks = sh->disks;
2919         int data_disks = raid_disks - conf->max_degraded;
2920         sector_t new_sector = sh->sector, check;
2921         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2922                                          : conf->chunk_sectors;
2923         int algorithm = previous ? conf->prev_algo
2924                                  : conf->algorithm;
2925         sector_t stripe;
2926         int chunk_offset;
2927         sector_t chunk_number;
2928         int dummy1, dd_idx = i;
2929         sector_t r_sector;
2930         struct stripe_head sh2;
2931
2932         chunk_offset = sector_div(new_sector, sectors_per_chunk);
2933         stripe = new_sector;
2934
2935         if (i == sh->pd_idx)
2936                 return 0;
2937         switch(conf->level) {
2938         case 4: break;
2939         case 5:
2940                 switch (algorithm) {
2941                 case ALGORITHM_LEFT_ASYMMETRIC:
2942                 case ALGORITHM_RIGHT_ASYMMETRIC:
2943                         if (i > sh->pd_idx)
2944                                 i--;
2945                         break;
2946                 case ALGORITHM_LEFT_SYMMETRIC:
2947                 case ALGORITHM_RIGHT_SYMMETRIC:
2948                         if (i < sh->pd_idx)
2949                                 i += raid_disks;
2950                         i -= (sh->pd_idx + 1);
2951                         break;
2952                 case ALGORITHM_PARITY_0:
2953                         i -= 1;
2954                         break;
2955                 case ALGORITHM_PARITY_N:
2956                         break;
2957                 default:
2958                         BUG();
2959                 }
2960                 break;
2961         case 6:
2962                 if (i == sh->qd_idx)
2963                         return 0; /* It is the Q disk */
2964                 switch (algorithm) {
2965                 case ALGORITHM_LEFT_ASYMMETRIC:
2966                 case ALGORITHM_RIGHT_ASYMMETRIC:
2967                 case ALGORITHM_ROTATING_ZERO_RESTART:
2968                 case ALGORITHM_ROTATING_N_RESTART:
2969                         if (sh->pd_idx == raid_disks-1)
2970                                 i--;    /* Q D D D P */
2971                         else if (i > sh->pd_idx)
2972                                 i -= 2; /* D D P Q D */
2973                         break;
2974                 case ALGORITHM_LEFT_SYMMETRIC:
2975                 case ALGORITHM_RIGHT_SYMMETRIC:
2976                         if (sh->pd_idx == raid_disks-1)
2977                                 i--; /* Q D D D P */
2978                         else {
2979                                 /* D D P Q D */
2980                                 if (i < sh->pd_idx)
2981                                         i += raid_disks;
2982                                 i -= (sh->pd_idx + 2);
2983                         }
2984                         break;
2985                 case ALGORITHM_PARITY_0:
2986                         i -= 2;
2987                         break;
2988                 case ALGORITHM_PARITY_N:
2989                         break;
2990                 case ALGORITHM_ROTATING_N_CONTINUE:
2991                         /* Like left_symmetric, but P is before Q */
2992                         if (sh->pd_idx == 0)
2993                                 i--;    /* P D D D Q */
2994                         else {
2995                                 /* D D Q P D */
2996                                 if (i < sh->pd_idx)
2997                                         i += raid_disks;
2998                                 i -= (sh->pd_idx + 1);
2999                         }
3000                         break;
3001                 case ALGORITHM_LEFT_ASYMMETRIC_6:
3002                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
3003                         if (i > sh->pd_idx)
3004                                 i--;
3005                         break;
3006                 case ALGORITHM_LEFT_SYMMETRIC_6:
3007                 case ALGORITHM_RIGHT_SYMMETRIC_6:
3008                         if (i < sh->pd_idx)
3009                                 i += data_disks + 1;
3010                         i -= (sh->pd_idx + 1);
3011                         break;
3012                 case ALGORITHM_PARITY_0_6:
3013                         i -= 1;
3014                         break;
3015                 default:
3016                         BUG();
3017                 }
3018                 break;
3019         }
3020
3021         chunk_number = stripe * data_disks + i;
3022         r_sector = chunk_number * sectors_per_chunk + chunk_offset;
3023
3024         check = raid5_compute_sector(conf, r_sector,
3025                                      previous, &dummy1, &sh2);
3026         if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
3027                 || sh2.qd_idx != sh->qd_idx) {
3028                 pr_warn("md/raid:%s: compute_blocknr: map not correct\n",
3029                         mdname(conf->mddev));
3030                 return 0;
3031         }
3032         return r_sector;
3033 }
3034
3035 /*
3036  * There are cases where we want handle_stripe_dirtying() and
3037  * schedule_reconstruction() to delay towrite to some dev of a stripe.
3038  *
3039  * This function checks whether we want to delay the towrite. Specifically,
3040  * we delay the towrite when:
3041  *
3042  *   1. degraded stripe has a non-overwrite to the missing dev, AND this
3043  *      stripe has data in journal (for other devices).
3044  *
3045  *      In this case, when reading data for the non-overwrite dev, it is
3046  *      necessary to handle complex rmw of write back cache (prexor with
3047  *      orig_page, and xor with page). To keep read path simple, we would
3048  *      like to flush data in journal to RAID disks first, so complex rmw
3049  *      is handled in the write patch (handle_stripe_dirtying).
3050  *
3051  *   2. when journal space is critical (R5C_LOG_CRITICAL=1)
3052  *
3053  *      It is important to be able to flush all stripes in raid5-cache.
3054  *      Therefore, we need reserve some space on the journal device for
3055  *      these flushes. If flush operation includes pending writes to the
3056  *      stripe, we need to reserve (conf->raid_disk + 1) pages per stripe
3057  *      for the flush out. If we exclude these pending writes from flush
3058  *      operation, we only need (conf->max_degraded + 1) pages per stripe.
3059  *      Therefore, excluding pending writes in these cases enables more
3060  *      efficient use of the journal device.
3061  *
3062  *      Note: To make sure the stripe makes progress, we only delay
3063  *      towrite for stripes with data already in journal (injournal > 0).
3064  *      When LOG_CRITICAL, stripes with injournal == 0 will be sent to
3065  *      no_space_stripes list.
3066  *
3067  *   3. during journal failure
3068  *      In journal failure, we try to flush all cached data to raid disks
3069  *      based on data in stripe cache. The array is read-only to upper
3070  *      layers, so we would skip all pending writes.
3071  *
3072  */
3073 static inline bool delay_towrite(struct r5conf *conf,
3074                                  struct r5dev *dev,
3075                                  struct stripe_head_state *s)
3076 {
3077         /* case 1 above */
3078         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3079             !test_bit(R5_Insync, &dev->flags) && s->injournal)
3080                 return true;
3081         /* case 2 above */
3082         if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
3083             s->injournal > 0)
3084                 return true;
3085         /* case 3 above */
3086         if (s->log_failed && s->injournal)
3087                 return true;
3088         return false;
3089 }
3090
3091 static void
3092 schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
3093                          int rcw, int expand)
3094 {
3095         int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx, disks = sh->disks;
3096         struct r5conf *conf = sh->raid_conf;
3097         int level = conf->level;
3098
3099         if (rcw) {
3100                 /*
3101                  * In some cases, handle_stripe_dirtying initially decided to
3102                  * run rmw and allocates extra page for prexor. However, rcw is
3103                  * cheaper later on. We need to free the extra page now,
3104                  * because we won't be able to do that in ops_complete_prexor().
3105                  */
3106                 r5c_release_extra_page(sh);
3107
3108                 for (i = disks; i--; ) {
3109                         struct r5dev *dev = &sh->dev[i];
3110
3111                         if (dev->towrite && !delay_towrite(conf, dev, s)) {
3112                                 set_bit(R5_LOCKED, &dev->flags);
3113                                 set_bit(R5_Wantdrain, &dev->flags);
3114                                 if (!expand)
3115                                         clear_bit(R5_UPTODATE, &dev->flags);
3116                                 s->locked++;
3117                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3118                                 set_bit(R5_LOCKED, &dev->flags);
3119                                 s->locked++;
3120                         }
3121                 }
3122                 /* if we are not expanding this is a proper write request, and
3123                  * there will be bios with new data to be drained into the
3124                  * stripe cache
3125                  */
3126                 if (!expand) {
3127                         if (!s->locked)
3128                                 /* False alarm, nothing to do */
3129                                 return;
3130                         sh->reconstruct_state = reconstruct_state_drain_run;
3131                         set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3132                 } else
3133                         sh->reconstruct_state = reconstruct_state_run;
3134
3135                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3136
3137                 if (s->locked + conf->max_degraded == disks)
3138                         if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
3139                                 atomic_inc(&conf->pending_full_writes);
3140         } else {
3141                 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
3142                         test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
3143                 BUG_ON(level == 6 &&
3144                         (!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
3145                            test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));
3146
3147                 for (i = disks; i--; ) {
3148                         struct r5dev *dev = &sh->dev[i];
3149                         if (i == pd_idx || i == qd_idx)
3150                                 continue;
3151
3152                         if (dev->towrite &&
3153                             (test_bit(R5_UPTODATE, &dev->flags) ||
3154                              test_bit(R5_Wantcompute, &dev->flags))) {
3155                                 set_bit(R5_Wantdrain, &dev->flags);
3156                                 set_bit(R5_LOCKED, &dev->flags);
3157                                 clear_bit(R5_UPTODATE, &dev->flags);
3158                                 s->locked++;
3159                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3160                                 set_bit(R5_LOCKED, &dev->flags);
3161                                 s->locked++;
3162                         }
3163                 }
3164                 if (!s->locked)
3165                         /* False alarm - nothing to do */
3166                         return;
3167                 sh->reconstruct_state = reconstruct_state_prexor_drain_run;
3168                 set_bit(STRIPE_OP_PREXOR, &s->ops_request);
3169                 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3170                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3171         }
3172
3173         /* keep the parity disk(s) locked while asynchronous operations
3174          * are in flight
3175          */
3176         set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
3177         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
3178         s->locked++;
3179
3180         if (level == 6) {
3181                 int qd_idx = sh->qd_idx;
3182                 struct r5dev *dev = &sh->dev[qd_idx];
3183
3184                 set_bit(R5_LOCKED, &dev->flags);
3185                 clear_bit(R5_UPTODATE, &dev->flags);
3186                 s->locked++;
3187         }
3188
3189         if (raid5_has_ppl(sh->raid_conf) && sh->ppl_page &&
3190             test_bit(STRIPE_OP_BIODRAIN, &s->ops_request) &&
3191             !test_bit(STRIPE_FULL_WRITE, &sh->state) &&
3192             test_bit(R5_Insync, &sh->dev[pd_idx].flags))
3193                 set_bit(STRIPE_OP_PARTIAL_PARITY, &s->ops_request);
3194
3195         pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
3196                 __func__, (unsigned long long)sh->sector,
3197                 s->locked, s->ops_request);
3198 }
3199
3200 /*
3201  * Each stripe/dev can have one or more bion attached.
3202  * toread/towrite point to the first in a chain.
3203  * The bi_next chain must be in order.
3204  */
3205 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx,
3206                           int forwrite, int previous)
3207 {
3208         struct bio **bip;
3209         struct r5conf *conf = sh->raid_conf;
3210         int firstwrite=0;
3211
3212         pr_debug("adding bi b#%llu to stripe s#%llu\n",
3213                 (unsigned long long)bi->bi_iter.bi_sector,
3214                 (unsigned long long)sh->sector);
3215
3216         spin_lock_irq(&sh->stripe_lock);
3217         sh->dev[dd_idx].write_hint = bi->bi_write_hint;
3218         /* Don't allow new IO added to stripes in batch list */
3219         if (sh->batch_head)
3220                 goto overlap;
3221         if (forwrite) {
3222                 bip = &sh->dev[dd_idx].towrite;
3223                 if (*bip == NULL)
3224                         firstwrite = 1;
3225         } else
3226                 bip = &sh->dev[dd_idx].toread;
3227         while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector) {
3228                 if (bio_end_sector(*bip) > bi->bi_iter.bi_sector)
3229                         goto overlap;
3230                 bip = & (*bip)->bi_next;
3231         }
3232         if (*bip && (*bip)->bi_iter.bi_sector < bio_end_sector(bi))
3233                 goto overlap;
3234
3235         if (forwrite && raid5_has_ppl(conf)) {
3236                 /*
3237                  * With PPL only writes to consecutive data chunks within a
3238                  * stripe are allowed because for a single stripe_head we can
3239                  * only have one PPL entry at a time, which describes one data
3240                  * range. Not really an overlap, but wait_for_overlap can be
3241                  * used to handle this.
3242                  */
3243                 sector_t sector;
3244                 sector_t first = 0;
3245                 sector_t last = 0;
3246                 int count = 0;
3247                 int i;
3248
3249                 for (i = 0; i < sh->disks; i++) {
3250                         if (i != sh->pd_idx &&
3251                             (i == dd_idx || sh->dev[i].towrite)) {
3252                                 sector = sh->dev[i].sector;
3253                                 if (count == 0 || sector < first)
3254                                         first = sector;
3255                                 if (sector > last)
3256                                         last = sector;
3257                                 count++;
3258                         }
3259                 }
3260
3261                 if (first + conf->chunk_sectors * (count - 1) != last)
3262                         goto overlap;
3263         }
3264
3265         if (!forwrite || previous)
3266                 clear_bit(STRIPE_BATCH_READY, &sh->state);
3267
3268         BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
3269         if (*bip)
3270                 bi->bi_next = *bip;
3271         *bip = bi;
3272         bio_inc_remaining(bi);
3273         md_write_inc(conf->mddev, bi);
3274
3275         if (forwrite) {
3276                 /* check if page is covered */
3277                 sector_t sector = sh->dev[dd_idx].sector;
3278                 for (bi=sh->dev[dd_idx].towrite;
3279                      sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
3280                              bi && bi->bi_iter.bi_sector <= sector;
3281                      bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
3282                         if (bio_end_sector(bi) >= sector)
3283                                 sector = bio_end_sector(bi);
3284                 }
3285                 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
3286                         if (!test_and_set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags))
3287                                 sh->overwrite_disks++;
3288         }
3289
3290         pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
3291                 (unsigned long long)(*bip)->bi_iter.bi_sector,
3292                 (unsigned long long)sh->sector, dd_idx);
3293
3294         if (conf->mddev->bitmap && firstwrite) {
3295                 /* Cannot hold spinlock over bitmap_startwrite,
3296                  * but must ensure this isn't added to a batch until
3297                  * we have added to the bitmap and set bm_seq.
3298                  * So set STRIPE_BITMAP_PENDING to prevent
3299                  * batching.
3300                  * If multiple add_stripe_bio() calls race here they
3301                  * much all set STRIPE_BITMAP_PENDING.  So only the first one
3302                  * to complete "bitmap_startwrite" gets to set
3303                  * STRIPE_BIT_DELAY.  This is important as once a stripe
3304                  * is added to a batch, STRIPE_BIT_DELAY cannot be changed
3305                  * any more.
3306                  */
3307                 set_bit(STRIPE_BITMAP_PENDING, &sh->state);
3308                 spin_unlock_irq(&sh->stripe_lock);
3309                 md_bitmap_startwrite(conf->mddev->bitmap, sh->sector,
3310                                      STRIPE_SECTORS, 0);
3311                 spin_lock_irq(&sh->stripe_lock);
3312                 clear_bit(STRIPE_BITMAP_PENDING, &sh->state);
3313                 if (!sh->batch_head) {
3314                         sh->bm_seq = conf->seq_flush+1;
3315                         set_bit(STRIPE_BIT_DELAY, &sh->state);
3316                 }
3317         }
3318         spin_unlock_irq(&sh->stripe_lock);
3319
3320         if (stripe_can_batch(sh))
3321                 stripe_add_to_batch_list(conf, sh);
3322         return 1;
3323
3324  overlap:
3325         set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
3326         spin_unlock_irq(&sh->stripe_lock);
3327         return 0;
3328 }
3329
3330 static void end_reshape(struct r5conf *conf);
3331
3332 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
3333                             struct stripe_head *sh)
3334 {
3335         int sectors_per_chunk =
3336                 previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
3337         int dd_idx;
3338         int chunk_offset = sector_div(stripe, sectors_per_chunk);
3339         int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
3340
3341         raid5_compute_sector(conf,
3342                              stripe * (disks - conf->max_degraded)
3343                              *sectors_per_chunk + chunk_offset,
3344                              previous,
3345                              &dd_idx, sh);
3346 }
3347
3348 static void
3349 handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
3350                      struct stripe_head_state *s, int disks)
3351 {
3352         int i;
3353         BUG_ON(sh->batch_head);
3354         for (i = disks; i--; ) {
3355                 struct bio *bi;
3356                 int bitmap_end = 0;
3357
3358                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
3359                         struct md_rdev *rdev;
3360                         rcu_read_lock();
3361                         rdev = rcu_dereference(conf->disks[i].rdev);
3362                         if (rdev && test_bit(In_sync, &rdev->flags) &&
3363                             !test_bit(Faulty, &rdev->flags))
3364                                 atomic_inc(&rdev->nr_pending);
3365                         else
3366                                 rdev = NULL;
3367                         rcu_read_unlock();
3368                         if (rdev) {
3369                                 if (!rdev_set_badblocks(
3370                                             rdev,
3371                                             sh->sector,
3372                                             STRIPE_SECTORS, 0))
3373                                         md_error(conf->mddev, rdev);
3374                                 rdev_dec_pending(rdev, conf->mddev);
3375                         }
3376                 }
3377                 spin_lock_irq(&sh->stripe_lock);
3378                 /* fail all writes first */
3379                 bi = sh->dev[i].towrite;
3380                 sh->dev[i].towrite = NULL;
3381                 sh->overwrite_disks = 0;
3382                 spin_unlock_irq(&sh->stripe_lock);
3383                 if (bi)
3384                         bitmap_end = 1;
3385
3386                 log_stripe_write_finished(sh);
3387
3388                 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3389                         wake_up(&conf->wait_for_overlap);
3390
3391                 while (bi && bi->bi_iter.bi_sector <
3392                         sh->dev[i].sector + STRIPE_SECTORS) {
3393                         struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
3394
3395                         md_write_end(conf->mddev);
3396                         bio_io_error(bi);
3397                         bi = nextbi;
3398                 }
3399                 if (bitmap_end)
3400                         md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3401                                            STRIPE_SECTORS, 0, 0);
3402                 bitmap_end = 0;
3403                 /* and fail all 'written' */
3404                 bi = sh->dev[i].written;
3405                 sh->dev[i].written = NULL;
3406                 if (test_and_clear_bit(R5_SkipCopy, &sh->dev[i].flags)) {
3407                         WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
3408                         sh->dev[i].page = sh->dev[i].orig_page;
3409                 }
3410
3411                 if (bi) bitmap_end = 1;
3412                 while (bi && bi->bi_iter.bi_sector <
3413                        sh->dev[i].sector + STRIPE_SECTORS) {
3414                         struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
3415
3416                         md_write_end(conf->mddev);
3417                         bio_io_error(bi);
3418                         bi = bi2;
3419                 }
3420
3421                 /* fail any reads if this device is non-operational and
3422                  * the data has not reached the cache yet.
3423                  */
3424                 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
3425                     s->failed > conf->max_degraded &&
3426                     (!test_bit(R5_Insync, &sh->dev[i].flags) ||
3427                       test_bit(R5_ReadError, &sh->dev[i].flags))) {
3428                         spin_lock_irq(&sh->stripe_lock);
3429                         bi = sh->dev[i].toread;
3430                         sh->dev[i].toread = NULL;
3431                         spin_unlock_irq(&sh->stripe_lock);
3432                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3433                                 wake_up(&conf->wait_for_overlap);
3434                         if (bi)
3435                                 s->to_read--;
3436                         while (bi && bi->bi_iter.bi_sector <
3437                                sh->dev[i].sector + STRIPE_SECTORS) {
3438                                 struct bio *nextbi =
3439                                         r5_next_bio(bi, sh->dev[i].sector);
3440
3441                                 bio_io_error(bi);
3442                                 bi = nextbi;
3443                         }
3444                 }
3445                 if (bitmap_end)
3446                         md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3447                                            STRIPE_SECTORS, 0, 0);
3448                 /* If we were in the middle of a write the parity block might
3449                  * still be locked - so just clear all R5_LOCKED flags
3450                  */
3451                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
3452         }
3453         s->to_write = 0;
3454         s->written = 0;
3455
3456         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3457                 if (atomic_dec_and_test(&conf->pending_full_writes))
3458                         md_wakeup_thread(conf->mddev->thread);
3459 }
3460
3461 static void
3462 handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
3463                    struct stripe_head_state *s)
3464 {
3465         int abort = 0;
3466         int i;
3467
3468         BUG_ON(sh->batch_head);
3469         clear_bit(STRIPE_SYNCING, &sh->state);
3470         if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
3471                 wake_up(&conf->wait_for_overlap);
3472         s->syncing = 0;
3473         s->replacing = 0;
3474         /* There is nothing more to do for sync/check/repair.
3475          * Don't even need to abort as that is handled elsewhere
3476          * if needed, and not always wanted e.g. if there is a known
3477          * bad block here.
3478          * For recover/replace we need to record a bad block on all
3479          * non-sync devices, or abort the recovery
3480          */
3481         if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
3482                 /* During recovery devices cannot be removed, so
3483                  * locking and refcounting of rdevs is not needed
3484                  */
3485                 rcu_read_lock();
3486                 for (i = 0; i < conf->raid_disks; i++) {
3487                         struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
3488                         if (rdev
3489                             && !test_bit(Faulty, &rdev->flags)
3490                             && !test_bit(In_sync, &rdev->flags)
3491                             && !rdev_set_badblocks(rdev, sh->sector,
3492                                                    STRIPE_SECTORS, 0))
3493                                 abort = 1;
3494                         rdev = rcu_dereference(conf->disks[i].replacement);
3495                         if (rdev
3496                             && !test_bit(Faulty, &rdev->flags)
3497                             && !test_bit(In_sync, &rdev->flags)
3498                             && !rdev_set_badblocks(rdev, sh->sector,
3499                                                    STRIPE_SECTORS, 0))
3500                                 abort = 1;
3501                 }
3502                 rcu_read_unlock();
3503                 if (abort)
3504                         conf->recovery_disabled =
3505                                 conf->mddev->recovery_disabled;
3506         }
3507         md_done_sync(conf->mddev, STRIPE_SECTORS, !abort);
3508 }
3509
3510 static int want_replace(struct stripe_head *sh, int disk_idx)
3511 {
3512         struct md_rdev *rdev;
3513         int rv = 0;
3514
3515         rcu_read_lock();
3516         rdev = rcu_dereference(sh->raid_conf->disks[disk_idx].replacement);
3517         if (rdev
3518             && !test_bit(Faulty, &rdev->flags)
3519             && !test_bit(In_sync, &rdev->flags)
3520             && (rdev->recovery_offset <= sh->sector
3521                 || rdev->mddev->recovery_cp <= sh->sector))
3522                 rv = 1;
3523         rcu_read_unlock();
3524         return rv;
3525 }
3526
3527 static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
3528                            int disk_idx, int disks)
3529 {
3530         struct r5dev *dev = &sh->dev[disk_idx];
3531         struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
3532                                   &sh->dev[s->failed_num[1]] };
3533         int i;
3534
3535
3536         if (test_bit(R5_LOCKED, &dev->flags) ||
3537             test_bit(R5_UPTODATE, &dev->flags))
3538                 /* No point reading this as we already have it or have
3539                  * decided to get it.
3540                  */
3541                 return 0;
3542
3543         if (dev->toread ||
3544             (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)))
3545                 /* We need this block to directly satisfy a request */
3546                 return 1;
3547
3548         if (s->syncing || s->expanding ||
3549             (s->replacing && want_replace(sh, disk_idx)))
3550                 /* When syncing, or expanding we read everything.
3551                  * When replacing, we need the replaced block.
3552                  */
3553                 return 1;
3554
3555         if ((s->failed >= 1 && fdev[0]->toread) ||
3556             (s->failed >= 2 && fdev[1]->toread))
3557                 /* If we want to read from a failed device, then
3558                  * we need to actually read every other device.
3559                  */
3560                 return 1;
3561
3562         /* Sometimes neither read-modify-write nor reconstruct-write
3563          * cycles can work.  In those cases we read every block we
3564          * can.  Then the parity-update is certain to have enough to
3565          * work with.
3566          * This can only be a problem when we need to write something,
3567          * and some device has failed.  If either of those tests
3568          * fail we need look no further.
3569          */
3570         if (!s->failed || !s->to_write)
3571                 return 0;
3572
3573         if (test_bit(R5_Insync, &dev->flags) &&
3574             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3575                 /* Pre-reads at not permitted until after short delay
3576                  * to gather multiple requests.  However if this
3577                  * device is no Insync, the block could only be computed
3578                  * and there is no need to delay that.
3579                  */
3580                 return 0;
3581
3582         for (i = 0; i < s->failed && i < 2; i++) {
3583                 if (fdev[i]->towrite &&
3584                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3585                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3586                         /* If we have a partial write to a failed
3587                          * device, then we will need to reconstruct
3588                          * the content of that device, so all other
3589                          * devices must be read.
3590                          */
3591                         return 1;
3592         }
3593
3594         /* If we are forced to do a reconstruct-write, either because
3595          * the current RAID6 implementation only supports that, or
3596          * because parity cannot be trusted and we are currently
3597          * recovering it, there is extra need to be careful.
3598          * If one of the devices that we would need to read, because
3599          * it is not being overwritten (and maybe not written at all)
3600          * is missing/faulty, then we need to read everything we can.
3601          */
3602         if (sh->raid_conf->level != 6 &&
3603             sh->sector < sh->raid_conf->mddev->recovery_cp)
3604                 /* reconstruct-write isn't being forced */
3605                 return 0;
3606         for (i = 0; i < s->failed && i < 2; i++) {
3607                 if (s->failed_num[i] != sh->pd_idx &&
3608                     s->failed_num[i] != sh->qd_idx &&
3609                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3610                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3611                         return 1;
3612         }
3613
3614         return 0;
3615 }
3616
3617 /* fetch_block - checks the given member device to see if its data needs
3618  * to be read or computed to satisfy a request.
3619  *
3620  * Returns 1 when no more member devices need to be checked, otherwise returns
3621  * 0 to tell the loop in handle_stripe_fill to continue
3622  */
3623 static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
3624                        int disk_idx, int disks)
3625 {
3626         struct r5dev *dev = &sh->dev[disk_idx];
3627
3628         /* is the data in this block needed, and can we get it? */
3629         if (need_this_block(sh, s, disk_idx, disks)) {
3630                 /* we would like to get this block, possibly by computing it,
3631                  * otherwise read it if the backing disk is insync
3632                  */
3633                 BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
3634                 BUG_ON(test_bit(R5_Wantread, &dev->flags));
3635                 BUG_ON(sh->batch_head);
3636
3637                 /*
3638                  * In the raid6 case if the only non-uptodate disk is P
3639                  * then we already trusted P to compute the other failed
3640                  * drives. It is safe to compute rather than re-read P.
3641                  * In other cases we only compute blocks from failed
3642                  * devices, otherwise check/repair might fail to detect
3643                  * a real inconsistency.
3644                  */
3645
3646                 if ((s->uptodate == disks - 1) &&
3647                     ((sh->qd_idx >= 0 && sh->pd_idx == disk_idx) ||
3648                     (s->failed && (disk_idx == s->failed_num[0] ||
3649                                    disk_idx == s->failed_num[1])))) {
3650                         /* have disk failed, and we're requested to fetch it;
3651                          * do compute it
3652                          */
3653                         pr_debug("Computing stripe %llu block %d\n",
3654                                (unsigned long long)sh->sector, disk_idx);
3655                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3656                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3657                         set_bit(R5_Wantcompute, &dev->flags);
3658                         sh->ops.target = disk_idx;
3659                         sh->ops.target2 = -1; /* no 2nd target */
3660                         s->req_compute = 1;
3661                         /* Careful: from this point on 'uptodate' is in the eye
3662                          * of raid_run_ops which services 'compute' operations
3663                          * before writes. R5_Wantcompute flags a block that will
3664                          * be R5_UPTODATE by the time it is needed for a
3665                          * subsequent operation.
3666                          */
3667                         s->uptodate++;
3668                         return 1;
3669                 } else if (s->uptodate == disks-2 && s->failed >= 2) {
3670                         /* Computing 2-failure is *very* expensive; only
3671                          * do it if failed >= 2
3672                          */
3673                         int other;
3674                         for (other = disks; other--; ) {
3675                                 if (other == disk_idx)
3676                                         continue;
3677                                 if (!test_bit(R5_UPTODATE,
3678                                       &sh->dev[other].flags))
3679                                         break;
3680                         }
3681                         BUG_ON(other < 0);
3682                         pr_debug("Computing stripe %llu blocks %d,%d\n",
3683                                (unsigned long long)sh->sector,
3684                                disk_idx, other);
3685                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3686                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3687                         set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
3688                         set_bit(R5_Wantcompute, &sh->dev[other].flags);
3689                         sh->ops.target = disk_idx;
3690                         sh->ops.target2 = other;
3691                         s->uptodate += 2;
3692                         s->req_compute = 1;
3693                         return 1;
3694                 } else if (test_bit(R5_Insync, &dev->flags)) {
3695                         set_bit(R5_LOCKED, &dev->flags);
3696                         set_bit(R5_Wantread, &dev->flags);
3697                         s->locked++;
3698                         pr_debug("Reading block %d (sync=%d)\n",
3699                                 disk_idx, s->syncing);
3700                 }
3701         }
3702
3703         return 0;
3704 }
3705
3706 /**
3707  * handle_stripe_fill - read or compute data to satisfy pending requests.
3708  */
3709 static void handle_stripe_fill(struct stripe_head *sh,
3710                                struct stripe_head_state *s,
3711                                int disks)
3712 {
3713         int i;
3714
3715         /* look for blocks to read/compute, skip this if a compute
3716          * is already in flight, or if the stripe contents are in the
3717          * midst of changing due to a write
3718          */
3719         if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
3720             !sh->reconstruct_state) {
3721
3722                 /*
3723                  * For degraded stripe with data in journal, do not handle
3724                  * read requests yet, instead, flush the stripe to raid
3725                  * disks first, this avoids handling complex rmw of write
3726                  * back cache (prexor with orig_page, and then xor with
3727                  * page) in the read path
3728                  */
3729                 if (s->injournal && s->failed) {
3730                         if (test_bit(STRIPE_R5C_CACHING, &sh->state))
3731                                 r5c_make_stripe_write_out(sh);
3732                         goto out;
3733                 }
3734
3735                 for (i = disks; i--; )
3736                         if (fetch_block(sh, s, i, disks))
3737                                 break;
3738         }
3739 out:
3740         set_bit(STRIPE_HANDLE, &sh->state);
3741 }
3742
3743 static void break_stripe_batch_list(struct stripe_head *head_sh,
3744                                     unsigned long handle_flags);
3745 /* handle_stripe_clean_event
3746  * any written block on an uptodate or failed drive can be returned.
3747  * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
3748  * never LOCKED, so we don't need to test 'failed' directly.
3749  */
3750 static void handle_stripe_clean_event(struct r5conf *conf,
3751         struct stripe_head *sh, int disks)
3752 {
3753         int i;
3754         struct r5dev *dev;
3755         int discard_pending = 0;
3756         struct stripe_head *head_sh = sh;
3757         bool do_endio = false;
3758
3759         for (i = disks; i--; )
3760                 if (sh->dev[i].written) {
3761                         dev = &sh->dev[i];
3762                         if (!test_bit(R5_LOCKED, &dev->flags) &&
3763                             (test_bit(R5_UPTODATE, &dev->flags) ||
3764                              test_bit(R5_Discard, &dev->flags) ||
3765                              test_bit(R5_SkipCopy, &dev->flags))) {
3766                                 /* We can return any write requests */
3767                                 struct bio *wbi, *wbi2;
3768                                 pr_debug("Return write for disc %d\n", i);
3769                                 if (test_and_clear_bit(R5_Discard, &dev->flags))
3770                                         clear_bit(R5_UPTODATE, &dev->flags);
3771                                 if (test_and_clear_bit(R5_SkipCopy, &dev->flags)) {
3772                                         WARN_ON(test_bit(R5_UPTODATE, &dev->flags));
3773                                 }
3774                                 do_endio = true;
3775
3776 returnbi:
3777                                 dev->page = dev->orig_page;
3778                                 wbi = dev->written;
3779                                 dev->written = NULL;
3780                                 while (wbi && wbi->bi_iter.bi_sector <
3781                                         dev->sector + STRIPE_SECTORS) {
3782                                         wbi2 = r5_next_bio(wbi, dev->sector);
3783                                         md_write_end(conf->mddev);
3784                                         bio_endio(wbi);
3785                                         wbi = wbi2;
3786                                 }
3787                                 md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3788                                                    STRIPE_SECTORS,
3789                                                    !test_bit(STRIPE_DEGRADED, &sh->state),
3790                                                    0);
3791                                 if (head_sh->batch_head) {
3792                                         sh = list_first_entry(&sh->batch_list,
3793                                                               struct stripe_head,
3794                                                               batch_list);
3795                                         if (sh != head_sh) {
3796                                                 dev = &sh->dev[i];
3797                                                 goto returnbi;
3798                                         }
3799                                 }
3800                                 sh = head_sh;
3801                                 dev = &sh->dev[i];
3802                         } else if (test_bit(R5_Discard, &dev->flags))
3803                                 discard_pending = 1;
3804                 }
3805
3806         log_stripe_write_finished(sh);
3807
3808         if (!discard_pending &&
3809             test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) {
3810                 int hash;
3811                 clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
3812                 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
3813                 if (sh->qd_idx >= 0) {
3814                         clear_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
3815                         clear_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags);
3816                 }
3817                 /* now that discard is done we can proceed with any sync */
3818                 clear_bit(STRIPE_DISCARD, &sh->state);
3819                 /*
3820                  * SCSI discard will change some bio fields and the stripe has
3821                  * no updated data, so remove it from hash list and the stripe
3822                  * will be reinitialized
3823                  */
3824 unhash:
3825                 hash = sh->hash_lock_index;
3826                 spin_lock_irq(conf->hash_locks + hash);
3827                 remove_hash(sh);
3828                 spin_unlock_irq(conf->hash_locks + hash);
3829                 if (head_sh->batch_head) {
3830                         sh = list_first_entry(&sh->batch_list,
3831                                               struct stripe_head, batch_list);
3832                         if (sh != head_sh)
3833                                         goto unhash;
3834                 }
3835                 sh = head_sh;
3836
3837                 if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
3838                         set_bit(STRIPE_HANDLE, &sh->state);
3839
3840         }
3841
3842         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3843                 if (atomic_dec_and_test(&conf->pending_full_writes))
3844                         md_wakeup_thread(conf->mddev->thread);
3845
3846         if (head_sh->batch_head && do_endio)
3847                 break_stripe_batch_list(head_sh, STRIPE_EXPAND_SYNC_FLAGS);
3848 }
3849
3850 /*
3851  * For RMW in write back cache, we need extra page in prexor to store the
3852  * old data. This page is stored in dev->orig_page.
3853  *
3854  * This function checks whether we have data for prexor. The exact logic
3855  * is:
3856  *       R5_UPTODATE && (!R5_InJournal || R5_OrigPageUPTDODATE)
3857  */
3858 static inline bool uptodate_for_rmw(struct r5dev *dev)
3859 {
3860         return (test_bit(R5_UPTODATE, &dev->flags)) &&
3861                 (!test_bit(R5_InJournal, &dev->flags) ||
3862                  test_bit(R5_OrigPageUPTDODATE, &dev->flags));
3863 }
3864
3865 static int handle_stripe_dirtying(struct r5conf *conf,
3866                                   struct stripe_head *sh,
3867                                   struct stripe_head_state *s,
3868                                   int disks)
3869 {
3870         int rmw = 0, rcw = 0, i;
3871         sector_t recovery_cp = conf->mddev->recovery_cp;
3872
3873         /* Check whether resync is now happening or should start.
3874          * If yes, then the array is dirty (after unclean shutdown or
3875          * initial creation), so parity in some stripes might be inconsistent.
3876          * In this case, we need to always do reconstruct-write, to ensure
3877          * that in case of drive failure or read-error correction, we
3878          * generate correct data from the parity.
3879          */
3880         if (conf->rmw_level == PARITY_DISABLE_RMW ||
3881             (recovery_cp < MaxSector && sh->sector >= recovery_cp &&
3882              s->failed == 0)) {
3883                 /* Calculate the real rcw later - for now make it
3884                  * look like rcw is cheaper
3885                  */
3886                 rcw = 1; rmw = 2;
3887                 pr_debug("force RCW rmw_level=%u, recovery_cp=%llu sh->sector=%llu\n",
3888                          conf->rmw_level, (unsigned long long)recovery_cp,
3889                          (unsigned long long)sh->sector);
3890         } else for (i = disks; i--; ) {
3891                 /* would I have to read this buffer for read_modify_write */
3892                 struct r5dev *dev = &sh->dev[i];
3893                 if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3894                      i == sh->pd_idx || i == sh->qd_idx ||
3895                      test_bit(R5_InJournal, &dev->flags)) &&
3896                     !test_bit(R5_LOCKED, &dev->flags) &&
3897                     !(uptodate_for_rmw(dev) ||
3898                       test_bit(R5_Wantcompute, &dev->flags))) {
3899                         if (test_bit(R5_Insync, &dev->flags))
3900                                 rmw++;
3901                         else
3902                                 rmw += 2*disks;  /* cannot read it */
3903                 }
3904                 /* Would I have to read this buffer for reconstruct_write */
3905                 if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3906                     i != sh->pd_idx && i != sh->qd_idx &&
3907                     !test_bit(R5_LOCKED, &dev->flags) &&
3908                     !(test_bit(R5_UPTODATE, &dev->flags) ||
3909                       test_bit(R5_Wantcompute, &dev->flags))) {
3910                         if (test_bit(R5_Insync, &dev->flags))
3911                                 rcw++;
3912                         else
3913                                 rcw += 2*disks;
3914                 }
3915         }
3916
3917         pr_debug("for sector %llu state 0x%lx, rmw=%d rcw=%d\n",
3918                  (unsigned long long)sh->sector, sh->state, rmw, rcw);
3919         set_bit(STRIPE_HANDLE, &sh->state);
3920         if ((rmw < rcw || (rmw == rcw && conf->rmw_level == PARITY_PREFER_RMW)) && rmw > 0) {
3921                 /* prefer read-modify-write, but need to get some data */
3922                 if (conf->mddev->queue)
3923                         blk_add_trace_msg(conf->mddev->queue,
3924                                           "raid5 rmw %llu %d",
3925                                           (unsigned long long)sh->sector, rmw);
3926                 for (i = disks; i--; ) {
3927                         struct r5dev *dev = &sh->dev[i];
3928                         if (test_bit(R5_InJournal, &dev->flags) &&
3929                             dev->page == dev->orig_page &&
3930                             !test_bit(R5_LOCKED, &sh->dev[sh->pd_idx].flags)) {
3931                                 /* alloc page for prexor */
3932                                 struct page *p = alloc_page(GFP_NOIO);
3933
3934                                 if (p) {
3935                                         dev->orig_page = p;
3936                                         continue;
3937                                 }
3938
3939                                 /*
3940                                  * alloc_page() failed, try use
3941                                  * disk_info->extra_page
3942                                  */
3943                                 if (!test_and_set_bit(R5C_EXTRA_PAGE_IN_USE,
3944                                                       &conf->cache_state)) {
3945                                         r5c_use_extra_page(sh);
3946                                         break;
3947                                 }
3948
3949                                 /* extra_page in use, add to delayed_list */
3950                                 set_bit(STRIPE_DELAYED, &sh->state);
3951                                 s->waiting_extra_page = 1;
3952                                 return -EAGAIN;
3953                         }
3954                 }
3955
3956                 for (i = disks; i--; ) {
3957                         struct r5dev *dev = &sh->dev[i];
3958                         if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3959                              i == sh->pd_idx || i == sh->qd_idx ||
3960                              test_bit(R5_InJournal, &dev->flags)) &&
3961                             !test_bit(R5_LOCKED, &dev->flags) &&
3962                             !(uptodate_for_rmw(dev) ||
3963                               test_bit(R5_Wantcompute, &dev->flags)) &&
3964                             test_bit(R5_Insync, &dev->flags)) {
3965                                 if (test_bit(STRIPE_PREREAD_ACTIVE,
3966                                              &sh->state)) {
3967                                         pr_debug("Read_old block %d for r-m-w\n",
3968                                                  i);
3969                                         set_bit(R5_LOCKED, &dev->flags);
3970                                         set_bit(R5_Wantread, &dev->flags);
3971                                         s->locked++;
3972                                 } else {
3973                                         set_bit(STRIPE_DELAYED, &sh->state);
3974                                         set_bit(STRIPE_HANDLE, &sh->state);
3975                                 }
3976                         }
3977                 }
3978         }
3979         if ((rcw < rmw || (rcw == rmw && conf->rmw_level != PARITY_PREFER_RMW)) && rcw > 0) {
3980                 /* want reconstruct write, but need to get some data */
3981                 int qread =0;
3982                 rcw = 0;
3983                 for (i = disks; i--; ) {
3984                         struct r5dev *dev = &sh->dev[i];
3985                         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3986                             i != sh->pd_idx && i != sh->qd_idx &&
3987                             !test_bit(R5_LOCKED, &dev->flags) &&
3988                             !(test_bit(R5_UPTODATE, &dev->flags) ||
3989                               test_bit(R5_Wantcompute, &dev->flags))) {
3990                                 rcw++;
3991                                 if (test_bit(R5_Insync, &dev->flags) &&
3992                                     test_bit(STRIPE_PREREAD_ACTIVE,
3993                                              &sh->state)) {
3994                                         pr_debug("Read_old block "
3995                                                 "%d for Reconstruct\n", i);
3996                                         set_bit(R5_LOCKED, &dev->flags);
3997                                         set_bit(R5_Wantread, &dev->flags);
3998                                         s->locked++;
3999                                         qread++;
4000                                 } else {
4001                                         set_bit(STRIPE_DELAYED, &sh->state);
4002                                         set_bit(STRIPE_HANDLE, &sh->state);
4003                                 }
4004                         }
4005                 }
4006                 if (rcw && conf->mddev->queue)
4007                         blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
4008                                           (unsigned long long)sh->sector,
4009                                           rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
4010         }
4011
4012         if (rcw > disks && rmw > disks &&
4013             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4014                 set_bit(STRIPE_DELAYED, &sh->state);
4015
4016         /* now if nothing is locked, and if we have enough data,
4017          * we can start a write request
4018          */
4019         /* since handle_stripe can be called at any time we need to handle the
4020          * case where a compute block operation has been submitted and then a
4021          * subsequent call wants to start a write request.  raid_run_ops only
4022          * handles the case where compute block and reconstruct are requested
4023          * simultaneously.  If this is not the case then new writes need to be
4024          * held off until the compute completes.
4025          */
4026         if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
4027             (s->locked == 0 && (rcw == 0 || rmw == 0) &&
4028              !test_bit(STRIPE_BIT_DELAY, &sh->state)))
4029                 schedule_reconstruction(sh, s, rcw == 0, 0);
4030         return 0;
4031 }
4032
4033 static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
4034                                 struct stripe_head_state *s, int disks)
4035 {
4036         struct r5dev *dev = NULL;
4037
4038         BUG_ON(sh->batch_head);
4039         set_bit(STRIPE_HANDLE, &sh->state);
4040
4041         switch (sh->check_state) {
4042         case check_state_idle:
4043                 /* start a new check operation if there are no failures */
4044                 if (s->failed == 0) {
4045                         BUG_ON(s->uptodate != disks);
4046                         sh->check_state = check_state_run;
4047                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4048                         clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4049                         s->uptodate--;
4050                         break;
4051                 }
4052                 dev = &sh->dev[s->failed_num[0]];
4053                 /* fall through */
4054         case check_state_compute_result:
4055                 sh->check_state = check_state_idle;
4056                 if (!dev)
4057                         dev = &sh->dev[sh->pd_idx];
4058
4059                 /* check that a write has not made the stripe insync */
4060                 if (test_bit(STRIPE_INSYNC, &sh->state))
4061                         break;
4062
4063                 /* either failed parity check, or recovery is happening */
4064                 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
4065                 BUG_ON(s->uptodate != disks);
4066
4067                 set_bit(R5_LOCKED, &dev->flags);
4068                 s->locked++;
4069                 set_bit(R5_Wantwrite, &dev->flags);
4070
4071                 clear_bit(STRIPE_DEGRADED, &sh->state);
4072                 set_bit(STRIPE_INSYNC, &sh->state);
4073                 break;
4074         case check_state_run:
4075                 break; /* we will be called again upon completion */
4076         case check_state_check_result:
4077                 sh->check_state = check_state_idle;
4078
4079                 /* if a failure occurred during the check operation, leave
4080                  * STRIPE_INSYNC not set and let the stripe be handled again
4081                  */
4082                 if (s->failed)
4083                         break;
4084
4085                 /* handle a successful check operation, if parity is correct
4086                  * we are done.  Otherwise update the mismatch count and repair
4087                  * parity if !MD_RECOVERY_CHECK
4088                  */
4089                 if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
4090                         /* parity is correct (on disc,
4091                          * not in buffer any more)
4092                          */
4093                         set_bit(STRIPE_INSYNC, &sh->state);
4094                 else {
4095                         atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
4096                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4097                                 /* don't try to repair!! */
4098                                 set_bit(STRIPE_INSYNC, &sh->state);
4099                                 pr_warn_ratelimited("%s: mismatch sector in range "
4100                                                     "%llu-%llu\n", mdname(conf->mddev),
4101                                                     (unsigned long long) sh->sector,
4102                                                     (unsigned long long) sh->sector +
4103                                                     STRIPE_SECTORS);
4104                         } else {
4105                                 sh->check_state = check_state_compute_run;
4106                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4107                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4108                                 set_bit(R5_Wantcompute,
4109                                         &sh->dev[sh->pd_idx].flags);
4110                                 sh->ops.target = sh->pd_idx;
4111                                 sh->ops.target2 = -1;
4112                                 s->uptodate++;
4113                         }
4114                 }
4115                 break;
4116         case check_state_compute_run:
4117                 break;
4118         default:
4119                 pr_err("%s: unknown check_state: %d sector: %llu\n",
4120                        __func__, sh->check_state,
4121                        (unsigned long long) sh->sector);
4122                 BUG();
4123         }
4124 }
4125
4126 static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
4127                                   struct stripe_head_state *s,
4128                                   int disks)
4129 {
4130         int pd_idx = sh->pd_idx;
4131         int qd_idx = sh->qd_idx;
4132         struct r5dev *dev;
4133
4134         BUG_ON(sh->batch_head);
4135         set_bit(STRIPE_HANDLE, &sh->state);
4136
4137         BUG_ON(s->failed > 2);
4138
4139         /* Want to check and possibly repair P and Q.
4140          * However there could be one 'failed' device, in which
4141          * case we can only check one of them, possibly using the
4142          * other to generate missing data
4143          */
4144
4145         switch (sh->check_state) {
4146         case check_state_idle:
4147                 /* start a new check operation if there are < 2 failures */
4148                 if (s->failed == s->q_failed) {
4149                         /* The only possible failed device holds Q, so it
4150                          * makes sense to check P (If anything else were failed,
4151                          * we would have used P to recreate it).
4152                          */
4153                         sh->check_state = check_state_run;
4154                 }
4155                 if (!s->q_failed && s->failed < 2) {
4156                         /* Q is not failed, and we didn't use it to generate
4157                          * anything, so it makes sense to check it
4158                          */
4159                         if (sh->check_state == check_state_run)
4160                                 sh->check_state = check_state_run_pq;
4161                         else
4162                                 sh->check_state = check_state_run_q;
4163                 }
4164
4165                 /* discard potentially stale zero_sum_result */
4166                 sh->ops.zero_sum_result = 0;
4167
4168                 if (sh->check_state == check_state_run) {
4169                         /* async_xor_zero_sum destroys the contents of P */
4170                         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
4171                         s->uptodate--;
4172                 }
4173                 if (sh->check_state >= check_state_run &&
4174                     sh->check_state <= check_state_run_pq) {
4175                         /* async_syndrome_zero_sum preserves P and Q, so
4176                          * no need to mark them !uptodate here
4177                          */
4178                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4179                         break;
4180                 }
4181
4182                 /* we have 2-disk failure */
4183                 BUG_ON(s->failed != 2);
4184                 /* fall through */
4185         case check_state_compute_result:
4186                 sh->check_state = check_state_idle;
4187
4188                 /* check that a write has not made the stripe insync */
4189                 if (test_bit(STRIPE_INSYNC, &sh->state))
4190                         break;
4191
4192                 /* now write out any block on a failed drive,
4193                  * or P or Q if they were recomputed
4194                  */
4195                 dev = NULL;
4196                 if (s->failed == 2) {
4197                         dev = &sh->dev[s->failed_num[1]];
4198                         s->locked++;
4199                         set_bit(R5_LOCKED, &dev->flags);
4200                         set_bit(R5_Wantwrite, &dev->flags);
4201                 }
4202                 if (s->failed >= 1) {
4203                         dev = &sh->dev[s->failed_num[0]];
4204                         s->locked++;
4205                         set_bit(R5_LOCKED, &dev->flags);
4206                         set_bit(R5_Wantwrite, &dev->flags);
4207                 }
4208                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4209                         dev = &sh->dev[pd_idx];
4210                         s->locked++;
4211                         set_bit(R5_LOCKED, &dev->flags);
4212                         set_bit(R5_Wantwrite, &dev->flags);
4213                 }
4214                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4215                         dev = &sh->dev[qd_idx];
4216                         s->locked++;
4217                         set_bit(R5_LOCKED, &dev->flags);
4218                         set_bit(R5_Wantwrite, &dev->flags);
4219                 }
4220                 if (WARN_ONCE(dev && !test_bit(R5_UPTODATE, &dev->flags),
4221                               "%s: disk%td not up to date\n",
4222                               mdname(conf->mddev),
4223                               dev - (struct r5dev *) &sh->dev)) {
4224                         clear_bit(R5_LOCKED, &dev->flags);
4225                         clear_bit(R5_Wantwrite, &dev->flags);
4226                         s->locked--;
4227                 }
4228                 clear_bit(STRIPE_DEGRADED, &sh->state);
4229
4230                 set_bit(STRIPE_INSYNC, &sh->state);
4231                 break;
4232         case check_state_run:
4233         case check_state_run_q:
4234         case check_state_run_pq:
4235                 break; /* we will be called again upon completion */
4236         case check_state_check_result:
4237                 sh->check_state = check_state_idle;
4238
4239                 /* handle a successful check operation, if parity is correct
4240                  * we are done.  Otherwise update the mismatch count and repair
4241                  * parity if !MD_RECOVERY_CHECK
4242                  */
4243                 if (sh->ops.zero_sum_result == 0) {
4244                         /* both parities are correct */
4245                         if (!s->failed)
4246                                 set_bit(STRIPE_INSYNC, &sh->state);
4247                         else {
4248                                 /* in contrast to the raid5 case we can validate
4249                                  * parity, but still have a failure to write
4250                                  * back
4251                                  */
4252                                 sh->check_state = check_state_compute_result;
4253                                 /* Returning at this point means that we may go
4254                                  * off and bring p and/or q uptodate again so
4255                                  * we make sure to check zero_sum_result again
4256                                  * to verify if p or q need writeback
4257                                  */
4258                         }
4259                 } else {
4260                         atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
4261                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4262                                 /* don't try to repair!! */
4263                                 set_bit(STRIPE_INSYNC, &sh->state);
4264                                 pr_warn_ratelimited("%s: mismatch sector in range "
4265                                                     "%llu-%llu\n", mdname(conf->mddev),
4266                                                     (unsigned long long) sh->sector,
4267                                                     (unsigned long long) sh->sector +
4268                                                     STRIPE_SECTORS);
4269                         } else {
4270                                 int *target = &sh->ops.target;
4271
4272                                 sh->ops.target = -1;
4273                                 sh->ops.target2 = -1;
4274                                 sh->check_state = check_state_compute_run;
4275                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4276                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4277                                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4278                                         set_bit(R5_Wantcompute,
4279                                                 &sh->dev[pd_idx].flags);
4280                                         *target = pd_idx;
4281                                         target = &sh->ops.target2;
4282                                         s->uptodate++;
4283                                 }
4284                                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4285                                         set_bit(R5_Wantcompute,
4286                                                 &sh->dev[qd_idx].flags);
4287                                         *target = qd_idx;
4288                                         s->uptodate++;
4289                                 }
4290                         }
4291                 }
4292                 break;
4293         case check_state_compute_run:
4294                 break;
4295         default:
4296                 pr_warn("%s: unknown check_state: %d sector: %llu\n",
4297                         __func__, sh->check_state,
4298                         (unsigned long long) sh->sector);
4299                 BUG();
4300         }
4301 }
4302
4303 static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
4304 {
4305         int i;
4306
4307         /* We have read all the blocks in this stripe and now we need to
4308          * copy some of them into a target stripe for expand.
4309          */
4310         struct dma_async_tx_descriptor *tx = NULL;
4311         BUG_ON(sh->batch_head);
4312         clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
4313         for (i = 0; i < sh->disks; i++)
4314                 if (i != sh->pd_idx && i != sh->qd_idx) {
4315                         int dd_idx, j;
4316                         struct stripe_head *sh2;
4317                         struct async_submit_ctl submit;
4318
4319                         sector_t bn = raid5_compute_blocknr(sh, i, 1);
4320                         sector_t s = raid5_compute_sector(conf, bn, 0,
4321                                                           &dd_idx, NULL);
4322                         sh2 = raid5_get_active_stripe(conf, s, 0, 1, 1);
4323                         if (sh2 == NULL)
4324                                 /* so far only the early blocks of this stripe
4325                                  * have been requested.  When later blocks
4326                                  * get requested, we will try again
4327                                  */
4328                                 continue;
4329                         if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
4330                            test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
4331                                 /* must have already done this block */
4332                                 raid5_release_stripe(sh2);
4333                                 continue;
4334                         }
4335
4336                         /* place all the copies on one channel */
4337                         init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
4338                         tx = async_memcpy(sh2->dev[dd_idx].page,
4339                                           sh->dev[i].page, 0, 0, STRIPE_SIZE,
4340                                           &submit);
4341
4342                         set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
4343                         set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
4344                         for (j = 0; j < conf->raid_disks; j++)
4345                                 if (j != sh2->pd_idx &&
4346                                     j != sh2->qd_idx &&
4347                                     !test_bit(R5_Expanded, &sh2->dev[j].flags))
4348                                         break;
4349                         if (j == conf->raid_disks) {
4350                                 set_bit(STRIPE_EXPAND_READY, &sh2->state);
4351                                 set_bit(STRIPE_HANDLE, &sh2->state);
4352                         }
4353                         raid5_release_stripe(sh2);
4354
4355                 }
4356         /* done submitting copies, wait for them to complete */
4357         async_tx_quiesce(&tx);
4358 }
4359
4360 /*
4361  * handle_stripe - do things to a stripe.
4362  *
4363  * We lock the stripe by setting STRIPE_ACTIVE and then examine the
4364  * state of various bits to see what needs to be done.
4365  * Possible results:
4366  *    return some read requests which now have data
4367  *    return some write requests which are safely on storage
4368  *    schedule a read on some buffers
4369  *    schedule a write of some buffers
4370  *    return confirmation of parity correctness
4371  *
4372  */
4373
4374 static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
4375 {
4376         struct r5conf *conf = sh->raid_conf;
4377         int disks = sh->disks;
4378         struct r5dev *dev;
4379         int i;
4380         int do_recovery = 0;
4381
4382         memset(s, 0, sizeof(*s));
4383
4384         s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state) && !sh->batch_head;
4385         s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state) && !sh->batch_head;
4386         s->failed_num[0] = -1;
4387         s->failed_num[1] = -1;
4388         s->log_failed = r5l_log_disk_error(conf);
4389
4390         /* Now to look around and see what can be done */
4391         rcu_read_lock();
4392         for (i=disks; i--; ) {
4393                 struct md_rdev *rdev;
4394                 sector_t first_bad;
4395                 int bad_sectors;
4396                 int is_bad = 0;
4397
4398                 dev = &sh->dev[i];
4399
4400                 pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
4401                          i, dev->flags,
4402                          dev->toread, dev->towrite, dev->written);
4403                 /* maybe we can reply to a read
4404                  *
4405                  * new wantfill requests are only permitted while
4406                  * ops_complete_biofill is guaranteed to be inactive
4407                  */
4408                 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
4409                     !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
4410                         set_bit(R5_Wantfill, &dev->flags);
4411
4412                 /* now count some things */
4413                 if (test_bit(R5_LOCKED, &dev->flags))
4414                         s->locked++;
4415                 if (test_bit(R5_UPTODATE, &dev->flags))
4416                         s->uptodate++;
4417                 if (test_bit(R5_Wantcompute, &dev->flags)) {
4418                         s->compute++;
4419                         BUG_ON(s->compute > 2);
4420                 }
4421
4422                 if (test_bit(R5_Wantfill, &dev->flags))
4423                         s->to_fill++;
4424                 else if (dev->toread)
4425                         s->to_read++;
4426                 if (dev->towrite) {
4427                         s->to_write++;
4428                         if (!test_bit(R5_OVERWRITE, &dev->flags))
4429                                 s->non_overwrite++;
4430                 }
4431                 if (dev->written)
4432                         s->written++;
4433                 /* Prefer to use the replacement for reads, but only
4434                  * if it is recovered enough and has no bad blocks.
4435                  */
4436                 rdev = rcu_dereference(conf->disks[i].replacement);
4437                 if (rdev && !test_bit(Faulty, &rdev->flags) &&
4438                     rdev->recovery_offset >= sh->sector + STRIPE_SECTORS &&
4439                     !is_badblock(rdev, sh->sector, STRIPE_SECTORS,
4440                                  &first_bad, &bad_sectors))
4441                         set_bit(R5_ReadRepl, &dev->flags);
4442                 else {
4443                         if (rdev && !test_bit(Faulty, &rdev->flags))
4444                                 set_bit(R5_NeedReplace, &dev->flags);
4445                         else
4446                                 clear_bit(R5_NeedReplace, &dev->flags);
4447                         rdev = rcu_dereference(conf->disks[i].rdev);
4448                         clear_bit(R5_ReadRepl, &dev->flags);
4449                 }
4450                 if (rdev && test_bit(Faulty, &rdev->flags))
4451                         rdev = NULL;
4452                 if (rdev) {
4453                         is_bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
4454                                              &first_bad, &bad_sectors);
4455                         if (s->blocked_rdev == NULL
4456                             && (test_bit(Blocked, &rdev->flags)
4457                                 || is_bad < 0)) {
4458                                 if (is_bad < 0)
4459                                         set_bit(BlockedBadBlocks,
4460                                                 &rdev->flags);
4461                                 s->blocked_rdev = rdev;
4462                                 atomic_inc(&rdev->nr_pending);
4463                         }
4464                 }
4465                 clear_bit(R5_Insync, &dev->flags);
4466                 if (!rdev)
4467                         /* Not in-sync */;
4468                 else if (is_bad) {
4469                         /* also not in-sync */
4470                         if (!test_bit(WriteErrorSeen, &rdev->flags) &&
4471                             test_bit(R5_UPTODATE, &dev->flags)) {
4472                                 /* treat as in-sync, but with a read error
4473                                  * which we can now try to correct
4474                                  */
4475                                 set_bit(R5_Insync, &dev->flags);
4476                                 set_bit(R5_ReadError, &dev->flags);
4477                         }
4478                 } else if (test_bit(In_sync, &rdev->flags))
4479                         set_bit(R5_Insync, &dev->flags);
4480                 else if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
4481                         /* in sync if before recovery_offset */
4482                         set_bit(R5_Insync, &dev->flags);
4483                 else if (test_bit(R5_UPTODATE, &dev->flags) &&
4484                          test_bit(R5_Expanded, &dev->flags))
4485                         /* If we've reshaped into here, we assume it is Insync.
4486                          * We will shortly update recovery_offset to make
4487                          * it official.
4488                          */
4489                         set_bit(R5_Insync, &dev->flags);
4490
4491                 if (test_bit(R5_WriteError, &dev->flags)) {
4492                         /* This flag does not apply to '.replacement'
4493                          * only to .rdev, so make sure to check that*/
4494                         struct md_rdev *rdev2 = rcu_dereference(
4495                                 conf->disks[i].rdev);
4496                         if (rdev2 == rdev)
4497                                 clear_bit(R5_Insync, &dev->flags);
4498                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4499                                 s->handle_bad_blocks = 1;
4500                                 atomic_inc(&rdev2->nr_pending);
4501                         } else
4502                                 clear_bit(R5_WriteError, &dev->flags);
4503                 }
4504                 if (test_bit(R5_MadeGood, &dev->flags)) {
4505                         /* This flag does not apply to '.replacement'
4506                          * only to .rdev, so make sure to check that*/
4507                         struct md_rdev *rdev2 = rcu_dereference(
4508                                 conf->disks[i].rdev);
4509                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4510                                 s->handle_bad_blocks = 1;
4511                                 atomic_inc(&rdev2->nr_pending);
4512                         } else
4513                                 clear_bit(R5_MadeGood, &dev->flags);
4514                 }
4515                 if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
4516                         struct md_rdev *rdev2 = rcu_dereference(
4517                                 conf->disks[i].replacement);
4518                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4519                                 s->handle_bad_blocks = 1;
4520                                 atomic_inc(&rdev2->nr_pending);
4521                         } else
4522                                 clear_bit(R5_MadeGoodRepl, &dev->flags);
4523                 }
4524                 if (!test_bit(R5_Insync, &dev->flags)) {
4525                         /* The ReadError flag will just be confusing now */
4526                         clear_bit(R5_ReadError, &dev->flags);
4527                         clear_bit(R5_ReWrite, &dev->flags);
4528                 }
4529                 if (test_bit(R5_ReadError, &dev->flags))
4530                         clear_bit(R5_Insync, &dev->flags);
4531                 if (!test_bit(R5_Insync, &dev->flags)) {
4532                         if (s->failed < 2)
4533                                 s->failed_num[s->failed] = i;
4534                         s->failed++;
4535                         if (rdev && !test_bit(Faulty, &rdev->flags))
4536                                 do_recovery = 1;
4537                         else if (!rdev) {
4538                                 rdev = rcu_dereference(
4539                                     conf->disks[i].replacement);
4540                                 if (rdev && !test_bit(Faulty, &rdev->flags))
4541                                         do_recovery = 1;
4542                         }
4543                 }
4544
4545                 if (test_bit(R5_InJournal, &dev->flags))
4546                         s->injournal++;
4547                 if (test_bit(R5_InJournal, &dev->flags) && dev->written)
4548                         s->just_cached++;
4549         }
4550         if (test_bit(STRIPE_SYNCING, &sh->state)) {
4551                 /* If there is a failed device being replaced,
4552                  *     we must be recovering.
4553                  * else if we are after recovery_cp, we must be syncing
4554                  * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
4555                  * else we can only be replacing
4556                  * sync and recovery both need to read all devices, and so
4557                  * use the same flag.
4558                  */
4559                 if (do_recovery ||
4560                     sh->sector >= conf->mddev->recovery_cp ||
4561                     test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
4562                         s->syncing = 1;
4563                 else
4564                         s->replacing = 1;
4565         }
4566         rcu_read_unlock();
4567 }
4568
4569 static int clear_batch_ready(struct stripe_head *sh)
4570 {
4571         /* Return '1' if this is a member of batch, or
4572          * '0' if it is a lone stripe or a head which can now be
4573          * handled.
4574          */
4575         struct stripe_head *tmp;
4576         if (!test_and_clear_bit(STRIPE_BATCH_READY, &sh->state))
4577                 return (sh->batch_head && sh->batch_head != sh);
4578         spin_lock(&sh->stripe_lock);
4579         if (!sh->batch_head) {
4580                 spin_unlock(&sh->stripe_lock);
4581                 return 0;
4582         }
4583
4584         /*
4585          * this stripe could be added to a batch list before we check
4586          * BATCH_READY, skips it
4587          */
4588         if (sh->batch_head != sh) {
4589                 spin_unlock(&sh->stripe_lock);
4590                 return 1;
4591         }
4592         spin_lock(&sh->batch_lock);
4593         list_for_each_entry(tmp, &sh->batch_list, batch_list)
4594                 clear_bit(STRIPE_BATCH_READY, &tmp->state);
4595         spin_unlock(&sh->batch_lock);
4596         spin_unlock(&sh->stripe_lock);
4597
4598         /*
4599          * BATCH_READY is cleared, no new stripes can be added.
4600          * batch_list can be accessed without lock
4601          */
4602         return 0;
4603 }
4604
4605 static void break_stripe_batch_list(struct stripe_head *head_sh,
4606                                     unsigned long handle_flags)
4607 {
4608         struct stripe_head *sh, *next;
4609         int i;
4610         int do_wakeup = 0;
4611
4612         list_for_each_entry_safe(sh, next, &head_sh->batch_list, batch_list) {
4613
4614                 list_del_init(&sh->batch_list);
4615
4616                 WARN_ONCE(sh->state & ((1 << STRIPE_ACTIVE) |
4617                                           (1 << STRIPE_SYNCING) |
4618                                           (1 << STRIPE_REPLACED) |
4619                                           (1 << STRIPE_DELAYED) |
4620                                           (1 << STRIPE_BIT_DELAY) |
4621                                           (1 << STRIPE_FULL_WRITE) |
4622                                           (1 << STRIPE_BIOFILL_RUN) |
4623                                           (1 << STRIPE_COMPUTE_RUN)  |
4624                                           (1 << STRIPE_DISCARD) |
4625                                           (1 << STRIPE_BATCH_READY) |
4626                                           (1 << STRIPE_BATCH_ERR) |
4627                                           (1 << STRIPE_BITMAP_PENDING)),
4628                         "stripe state: %lx\n", sh->state);
4629                 WARN_ONCE(head_sh->state & ((1 << STRIPE_DISCARD) |
4630                                               (1 << STRIPE_REPLACED)),
4631                         "head stripe state: %lx\n", head_sh->state);
4632
4633                 set_mask_bits(&sh->state, ~(STRIPE_EXPAND_SYNC_FLAGS |
4634                                             (1 << STRIPE_PREREAD_ACTIVE) |
4635                                             (1 << STRIPE_DEGRADED) |
4636                                             (1 << STRIPE_ON_UNPLUG_LIST)),
4637                               head_sh->state & (1 << STRIPE_INSYNC));
4638
4639                 sh->check_state = head_sh->check_state;
4640                 sh->reconstruct_state = head_sh->reconstruct_state;
4641                 spin_lock_irq(&sh->stripe_lock);
4642                 sh->batch_head = NULL;
4643                 spin_unlock_irq(&sh->stripe_lock);
4644                 for (i = 0; i < sh->disks; i++) {
4645                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
4646                                 do_wakeup = 1;
4647                         sh->dev[i].flags = head_sh->dev[i].flags &
4648                                 (~((1 << R5_WriteError) | (1 << R5_Overlap)));
4649                 }
4650                 if (handle_flags == 0 ||
4651                     sh->state & handle_flags)
4652                         set_bit(STRIPE_HANDLE, &sh->state);
4653                 raid5_release_stripe(sh);
4654         }
4655         spin_lock_irq(&head_sh->stripe_lock);
4656         head_sh->batch_head = NULL;
4657         spin_unlock_irq(&head_sh->stripe_lock);
4658         for (i = 0; i < head_sh->disks; i++)
4659                 if (test_and_clear_bit(R5_Overlap, &head_sh->dev[i].flags))
4660                         do_wakeup = 1;
4661         if (head_sh->state & handle_flags)
4662                 set_bit(STRIPE_HANDLE, &head_sh->state);
4663
4664         if (do_wakeup)
4665                 wake_up(&head_sh->raid_conf->wait_for_overlap);
4666 }
4667
4668 static void handle_stripe(struct stripe_head *sh)
4669 {
4670         struct stripe_head_state s;
4671         struct r5conf *conf = sh->raid_conf;
4672         int i;
4673         int prexor;
4674         int disks = sh->disks;
4675         struct r5dev *pdev, *qdev;
4676
4677         clear_bit(STRIPE_HANDLE, &sh->state);
4678         if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
4679                 /* already being handled, ensure it gets handled
4680                  * again when current action finishes */
4681                 set_bit(STRIPE_HANDLE, &sh->state);
4682                 return;
4683         }
4684
4685         if (clear_batch_ready(sh) ) {
4686                 clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
4687                 return;
4688         }
4689
4690         if (test_and_clear_bit(STRIPE_BATCH_ERR, &sh->state))
4691                 break_stripe_batch_list(sh, 0);
4692
4693         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) && !sh->batch_head) {
4694                 spin_lock(&sh->stripe_lock);
4695                 /*
4696                  * Cannot process 'sync' concurrently with 'discard'.
4697                  * Flush data in r5cache before 'sync'.
4698                  */
4699                 if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) &&
4700                     !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) &&
4701                     !test_bit(STRIPE_DISCARD, &sh->state) &&
4702                     test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
4703                         set_bit(STRIPE_SYNCING, &sh->state);
4704                         clear_bit(STRIPE_INSYNC, &sh->state);
4705                         clear_bit(STRIPE_REPLACED, &sh->state);
4706                 }
4707                 spin_unlock(&sh->stripe_lock);
4708         }
4709         clear_bit(STRIPE_DELAYED, &sh->state);
4710
4711         pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
4712                 "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
4713                (unsigned long long)sh->sector, sh->state,
4714                atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
4715                sh->check_state, sh->reconstruct_state);
4716
4717         analyse_stripe(sh, &s);
4718
4719         if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
4720                 goto finish;
4721
4722         if (s.handle_bad_blocks ||
4723             test_bit(MD_SB_CHANGE_PENDING, &conf->mddev->sb_flags)) {
4724                 set_bit(STRIPE_HANDLE, &sh->state);
4725                 goto finish;
4726         }
4727
4728         if (unlikely(s.blocked_rdev)) {
4729                 if (s.syncing || s.expanding || s.expanded ||
4730                     s.replacing || s.to_write || s.written) {
4731                         set_bit(STRIPE_HANDLE, &sh->state);
4732                         goto finish;
4733                 }
4734                 /* There is nothing for the blocked_rdev to block */
4735                 rdev_dec_pending(s.blocked_rdev, conf->mddev);
4736                 s.blocked_rdev = NULL;
4737         }
4738
4739         if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
4740                 set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
4741                 set_bit(STRIPE_BIOFILL_RUN, &sh->state);
4742         }
4743
4744         pr_debug("locked=%d uptodate=%d to_read=%d"
4745                " to_write=%d failed=%d failed_num=%d,%d\n",
4746                s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
4747                s.failed_num[0], s.failed_num[1]);
4748         /*
4749          * check if the array has lost more than max_degraded devices and,
4750          * if so, some requests might need to be failed.
4751          *
4752          * When journal device failed (log_failed), we will only process
4753          * the stripe if there is data need write to raid disks
4754          */
4755         if (s.failed > conf->max_degraded ||
4756             (s.log_failed && s.injournal == 0)) {
4757                 sh->check_state = 0;
4758                 sh->reconstruct_state = 0;
4759                 break_stripe_batch_list(sh, 0);
4760                 if (s.to_read+s.to_write+s.written)
4761                         handle_failed_stripe(conf, sh, &s, disks);
4762                 if (s.syncing + s.replacing)
4763                         handle_failed_sync(conf, sh, &s);
4764         }
4765
4766         /* Now we check to see if any write operations have recently
4767          * completed
4768          */
4769         prexor = 0;
4770         if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
4771                 prexor = 1;
4772         if (sh->reconstruct_state == reconstruct_state_drain_result ||
4773             sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
4774                 sh->reconstruct_state = reconstruct_state_idle;
4775
4776                 /* All the 'written' buffers and the parity block are ready to
4777                  * be written back to disk
4778                  */
4779                 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
4780                        !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
4781                 BUG_ON(sh->qd_idx >= 0 &&
4782                        !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
4783                        !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
4784                 for (i = disks; i--; ) {
4785                         struct r5dev *dev = &sh->dev[i];
4786                         if (test_bit(R5_LOCKED, &dev->flags) &&
4787                                 (i == sh->pd_idx || i == sh->qd_idx ||
4788                                  dev->written || test_bit(R5_InJournal,
4789                                                           &dev->flags))) {
4790                                 pr_debug("Writing block %d\n", i);
4791                                 set_bit(R5_Wantwrite, &dev->flags);
4792                                 if (prexor)
4793                                         continue;
4794                                 if (s.failed > 1)
4795                                         continue;
4796                                 if (!test_bit(R5_Insync, &dev->flags) ||
4797                                     ((i == sh->pd_idx || i == sh->qd_idx)  &&
4798                                      s.failed == 0))
4799                                         set_bit(STRIPE_INSYNC, &sh->state);
4800                         }
4801                 }
4802                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4803                         s.dec_preread_active = 1;
4804         }
4805
4806         /*
4807          * might be able to return some write requests if the parity blocks
4808          * are safe, or on a failed drive
4809          */
4810         pdev = &sh->dev[sh->pd_idx];
4811         s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
4812                 || (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
4813         qdev = &sh->dev[sh->qd_idx];
4814         s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
4815                 || (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
4816                 || conf->level < 6;
4817
4818         if (s.written &&
4819             (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
4820                              && !test_bit(R5_LOCKED, &pdev->flags)
4821                              && (test_bit(R5_UPTODATE, &pdev->flags) ||
4822                                  test_bit(R5_Discard, &pdev->flags))))) &&
4823             (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
4824                              && !test_bit(R5_LOCKED, &qdev->flags)
4825                              && (test_bit(R5_UPTODATE, &qdev->flags) ||
4826                                  test_bit(R5_Discard, &qdev->flags))))))
4827                 handle_stripe_clean_event(conf, sh, disks);
4828
4829         if (s.just_cached)
4830                 r5c_handle_cached_data_endio(conf, sh, disks);
4831         log_stripe_write_finished(sh);
4832
4833         /* Now we might consider reading some blocks, either to check/generate
4834          * parity, or to satisfy requests
4835          * or to load a block that is being partially written.
4836          */
4837         if (s.to_read || s.non_overwrite
4838             || (conf->level == 6 && s.to_write && s.failed)
4839             || (s.syncing && (s.uptodate + s.compute < disks))
4840             || s.replacing
4841             || s.expanding)
4842                 handle_stripe_fill(sh, &s, disks);
4843
4844         /*
4845          * When the stripe finishes full journal write cycle (write to journal
4846          * and raid disk), this is the clean up procedure so it is ready for
4847          * next operation.
4848          */
4849         r5c_finish_stripe_write_out(conf, sh, &s);
4850
4851         /*
4852          * Now to consider new write requests, cache write back and what else,
4853          * if anything should be read.  We do not handle new writes when:
4854          * 1/ A 'write' operation (copy+xor) is already in flight.
4855          * 2/ A 'check' operation is in flight, as it may clobber the parity
4856          *    block.
4857          * 3/ A r5c cache log write is in flight.
4858          */
4859
4860         if (!sh->reconstruct_state && !sh->check_state && !sh->log_io) {
4861                 if (!r5c_is_writeback(conf->log)) {
4862                         if (s.to_write)
4863                                 handle_stripe_dirtying(conf, sh, &s, disks);
4864                 } else { /* write back cache */
4865                         int ret = 0;
4866
4867                         /* First, try handle writes in caching phase */
4868                         if (s.to_write)
4869                                 ret = r5c_try_caching_write(conf, sh, &s,
4870                                                             disks);
4871                         /*
4872                          * If caching phase failed: ret == -EAGAIN
4873                          *    OR
4874                          * stripe under reclaim: !caching && injournal
4875                          *
4876                          * fall back to handle_stripe_dirtying()
4877                          */
4878                         if (ret == -EAGAIN ||
4879                             /* stripe under reclaim: !caching && injournal */
4880                             (!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
4881                              s.injournal > 0)) {
4882                                 ret = handle_stripe_dirtying(conf, sh, &s,
4883                                                              disks);
4884                                 if (ret == -EAGAIN)
4885                                         goto finish;
4886                         }
4887                 }
4888         }
4889
4890         /* maybe we need to check and possibly fix the parity for this stripe
4891          * Any reads will already have been scheduled, so we just see if enough
4892          * data is available.  The parity check is held off while parity
4893          * dependent operations are in flight.
4894          */
4895         if (sh->check_state ||
4896             (s.syncing && s.locked == 0 &&
4897              !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4898              !test_bit(STRIPE_INSYNC, &sh->state))) {
4899                 if (conf->level == 6)
4900                         handle_parity_checks6(conf, sh, &s, disks);
4901                 else
4902                         handle_parity_checks5(conf, sh, &s, disks);
4903         }
4904
4905         if ((s.replacing || s.syncing) && s.locked == 0
4906             && !test_bit(STRIPE_COMPUTE_RUN, &sh->state)
4907             && !test_bit(STRIPE_REPLACED, &sh->state)) {
4908                 /* Write out to replacement devices where possible */
4909                 for (i = 0; i < conf->raid_disks; i++)
4910                         if (test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
4911                                 WARN_ON(!test_bit(R5_UPTODATE, &sh->dev[i].flags));
4912                                 set_bit(R5_WantReplace, &sh->dev[i].flags);
4913                                 set_bit(R5_LOCKED, &sh->dev[i].flags);
4914                                 s.locked++;
4915                         }
4916                 if (s.replacing)
4917                         set_bit(STRIPE_INSYNC, &sh->state);
4918                 set_bit(STRIPE_REPLACED, &sh->state);
4919         }
4920         if ((s.syncing || s.replacing) && s.locked == 0 &&
4921             !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4922             test_bit(STRIPE_INSYNC, &sh->state)) {
4923                 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
4924                 clear_bit(STRIPE_SYNCING, &sh->state);
4925                 if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
4926                         wake_up(&conf->wait_for_overlap);
4927         }
4928
4929         /* If the failed drives are just a ReadError, then we might need
4930          * to progress the repair/check process
4931          */
4932         if (s.failed <= conf->max_degraded && !conf->mddev->ro)
4933                 for (i = 0; i < s.failed; i++) {
4934                         struct r5dev *dev = &sh->dev[s.failed_num[i]];
4935                         if (test_bit(R5_ReadError, &dev->flags)
4936                             && !test_bit(R5_LOCKED, &dev->flags)
4937                             && test_bit(R5_UPTODATE, &dev->flags)
4938                                 ) {
4939                                 if (!test_bit(R5_ReWrite, &dev->flags)) {
4940                                         set_bit(R5_Wantwrite, &dev->flags);
4941                                         set_bit(R5_ReWrite, &dev->flags);
4942                                         set_bit(R5_LOCKED, &dev->flags);
4943                                         s.locked++;
4944                                 } else {
4945                                         /* let's read it back */
4946                                         set_bit(R5_Wantread, &dev->flags);
4947                                         set_bit(R5_LOCKED, &dev->flags);
4948                                         s.locked++;
4949                                 }
4950                         }
4951                 }
4952
4953         /* Finish reconstruct operations initiated by the expansion process */
4954         if (sh->reconstruct_state == reconstruct_state_result) {
4955                 struct stripe_head *sh_src
4956                         = raid5_get_active_stripe(conf, sh->sector, 1, 1, 1);
4957                 if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
4958                         /* sh cannot be written until sh_src has been read.
4959                          * so arrange for sh to be delayed a little
4960                          */
4961                         set_bit(STRIPE_DELAYED, &sh->state);
4962                         set_bit(STRIPE_HANDLE, &sh->state);
4963                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
4964                                               &sh_src->state))
4965                                 atomic_inc(&conf->preread_active_stripes);
4966                         raid5_release_stripe(sh_src);
4967                         goto finish;
4968                 }
4969                 if (sh_src)
4970                         raid5_release_stripe(sh_src);
4971
4972                 sh->reconstruct_state = reconstruct_state_idle;
4973                 clear_bit(STRIPE_EXPANDING, &sh->state);
4974                 for (i = conf->raid_disks; i--; ) {
4975                         set_bit(R5_Wantwrite, &sh->dev[i].flags);
4976                         set_bit(R5_LOCKED, &sh->dev[i].flags);
4977                         s.locked++;
4978                 }
4979         }
4980
4981         if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
4982             !sh->reconstruct_state) {
4983                 /* Need to write out all blocks after computing parity */
4984                 sh->disks = conf->raid_disks;
4985                 stripe_set_idx(sh->sector, conf, 0, sh);
4986                 schedule_reconstruction(sh, &s, 1, 1);
4987         } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
4988                 clear_bit(STRIPE_EXPAND_READY, &sh->state);
4989                 atomic_dec(&conf->reshape_stripes);
4990                 wake_up(&conf->wait_for_overlap);
4991                 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
4992         }
4993
4994         if (s.expanding && s.locked == 0 &&
4995             !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
4996                 handle_stripe_expansion(conf, sh);
4997
4998 finish:
4999         /* wait for this device to become unblocked */
5000         if (unlikely(s.blocked_rdev)) {
5001                 if (conf->mddev->external)
5002                         md_wait_for_blocked_rdev(s.blocked_rdev,
5003                                                  conf->mddev);
5004                 else
5005                         /* Internal metadata will immediately
5006                          * be written by raid5d, so we don't
5007                          * need to wait here.
5008                          */
5009                         rdev_dec_pending(s.blocked_rdev,
5010                                          conf->mddev);
5011         }
5012
5013         if (s.handle_bad_blocks)
5014                 for (i = disks; i--; ) {
5015                         struct md_rdev *rdev;
5016                         struct r5dev *dev = &sh->dev[i];
5017                         if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
5018                                 /* We own a safe reference to the rdev */
5019                                 rdev = conf->disks[i].rdev;
5020                                 if (!rdev_set_badblocks(rdev, sh->sector,
5021                                                         STRIPE_SECTORS, 0))
5022                                         md_error(conf->mddev, rdev);
5023                                 rdev_dec_pending(rdev, conf->mddev);
5024                         }
5025                         if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
5026                                 rdev = conf->disks[i].rdev;
5027                                 rdev_clear_badblocks(rdev, sh->sector,
5028                                                      STRIPE_SECTORS, 0);
5029                                 rdev_dec_pending(rdev, conf->mddev);
5030                         }
5031                         if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
5032                                 rdev = conf->disks[i].replacement;
5033                                 if (!rdev)
5034                                         /* rdev have been moved down */
5035                                         rdev = conf->disks[i].rdev;
5036                                 rdev_clear_badblocks(rdev, sh->sector,
5037                                                      STRIPE_SECTORS, 0);
5038                                 rdev_dec_pending(rdev, conf->mddev);
5039                         }
5040                 }
5041
5042         if (s.ops_request)
5043                 raid_run_ops(sh, s.ops_request);
5044
5045         ops_run_io(sh, &s);
5046
5047         if (s.dec_preread_active) {
5048                 /* We delay this until after ops_run_io so that if make_request
5049                  * is waiting on a flush, it won't continue until the writes
5050                  * have actually been submitted.
5051                  */
5052                 atomic_dec(&conf->preread_active_stripes);
5053                 if (atomic_read(&conf->preread_active_stripes) <
5054                     IO_THRESHOLD)
5055                         md_wakeup_thread(conf->mddev->thread);
5056         }
5057
5058         clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
5059 }
5060
5061 static void raid5_activate_delayed(struct r5conf *conf)
5062 {
5063         if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
5064                 while (!list_empty(&conf->delayed_list)) {
5065                         struct list_head *l = conf->delayed_list.next;
5066                         struct stripe_head *sh;
5067                         sh = list_entry(l, struct stripe_head, lru);
5068                         list_del_init(l);
5069                         clear_bit(STRIPE_DELAYED, &sh->state);
5070                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5071                                 atomic_inc(&conf->preread_active_stripes);
5072                         list_add_tail(&sh->lru, &conf->hold_list);
5073                         raid5_wakeup_stripe_thread(sh);
5074                 }
5075         }
5076 }
5077
5078 static void activate_bit_delay(struct r5conf *conf,
5079         struct list_head *temp_inactive_list)
5080 {
5081         /* device_lock is held */
5082         struct list_head head;
5083         list_add(&head, &conf->bitmap_list);
5084         list_del_init(&conf->bitmap_list);
5085         while (!list_empty(&head)) {
5086                 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
5087                 int hash;
5088                 list_del_init(&sh->lru);
5089                 atomic_inc(&sh->count);
5090                 hash = sh->hash_lock_index;
5091                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
5092         }
5093 }
5094
5095 static int raid5_congested(struct mddev *mddev, int bits)
5096 {
5097         struct r5conf *conf = mddev->private;
5098
5099         /* No difference between reads and writes.  Just check
5100          * how busy the stripe_cache is
5101          */
5102
5103         if (test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
5104                 return 1;
5105
5106         /* Also checks whether there is pressure on r5cache log space */
5107         if (test_bit(R5C_LOG_TIGHT, &conf->cache_state))
5108                 return 1;
5109         if (conf->quiesce)
5110                 return 1;
5111         if (atomic_read(&conf->empty_inactive_list_nr))
5112                 return 1;
5113
5114         return 0;
5115 }
5116
5117 static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
5118 {
5119         struct r5conf *conf = mddev->private;
5120         sector_t sector = bio->bi_iter.bi_sector;
5121         unsigned int chunk_sectors;
5122         unsigned int bio_sectors = bio_sectors(bio);
5123
5124         WARN_ON_ONCE(bio->bi_partno);
5125
5126         chunk_sectors = min(conf->chunk_sectors, conf->prev_chunk_sectors);
5127         return  chunk_sectors >=
5128                 ((sector & (chunk_sectors - 1)) + bio_sectors);
5129 }
5130
5131 /*
5132  *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
5133  *  later sampled by raid5d.
5134  */
5135 static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
5136 {
5137         unsigned long flags;
5138
5139         spin_lock_irqsave(&conf->device_lock, flags);
5140
5141         bi->bi_next = conf->retry_read_aligned_list;
5142         conf->retry_read_aligned_list = bi;
5143
5144         spin_unlock_irqrestore(&conf->device_lock, flags);
5145         md_wakeup_thread(conf->mddev->thread);
5146 }
5147
5148 static struct bio *remove_bio_from_retry(struct r5conf *conf,
5149                                          unsigned int *offset)
5150 {
5151         struct bio *bi;
5152
5153         bi = conf->retry_read_aligned;
5154         if (bi) {
5155                 *offset = conf->retry_read_offset;
5156                 conf->retry_read_aligned = NULL;
5157                 return bi;
5158         }
5159         bi = conf->retry_read_aligned_list;
5160         if(bi) {
5161                 conf->retry_read_aligned_list = bi->bi_next;
5162                 bi->bi_next = NULL;
5163                 *offset = 0;
5164         }
5165
5166         return bi;
5167 }
5168
5169 /*
5170  *  The "raid5_align_endio" should check if the read succeeded and if it
5171  *  did, call bio_endio on the original bio (having bio_put the new bio
5172  *  first).
5173  *  If the read failed..
5174  */
5175 static void raid5_align_endio(struct bio *bi)
5176 {
5177         struct bio* raid_bi  = bi->bi_private;
5178         struct mddev *mddev;
5179         struct r5conf *conf;
5180         struct md_rdev *rdev;
5181         blk_status_t error = bi->bi_status;
5182
5183         bio_put(bi);
5184
5185         rdev = (void*)raid_bi->bi_next;
5186         raid_bi->bi_next = NULL;
5187         mddev = rdev->mddev;
5188         conf = mddev->private;
5189
5190         rdev_dec_pending(rdev, conf->mddev);
5191
5192         if (!error) {
5193                 bio_endio(raid_bi);
5194                 if (atomic_dec_and_test(&conf->active_aligned_reads))
5195                         wake_up(&conf->wait_for_quiescent);
5196                 return;
5197         }
5198
5199         pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
5200
5201         add_bio_to_retry(raid_bi, conf);
5202 }
5203
5204 static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
5205 {
5206         struct r5conf *conf = mddev->private;
5207         int dd_idx;
5208         struct bio* align_bi;
5209         struct md_rdev *rdev;
5210         sector_t end_sector;
5211
5212         if (!in_chunk_boundary(mddev, raid_bio)) {
5213                 pr_debug("%s: non aligned\n", __func__);
5214                 return 0;
5215         }
5216         /*
5217          * use bio_clone_fast to make a copy of the bio
5218          */
5219         align_bi = bio_clone_fast(raid_bio, GFP_NOIO, &mddev->bio_set);
5220         if (!align_bi)
5221                 return 0;
5222         /*
5223          *   set bi_end_io to a new function, and set bi_private to the
5224          *     original bio.
5225          */
5226         align_bi->bi_end_io  = raid5_align_endio;
5227         align_bi->bi_private = raid_bio;
5228         /*
5229          *      compute position
5230          */
5231         align_bi->bi_iter.bi_sector =
5232                 raid5_compute_sector(conf, raid_bio->bi_iter.bi_sector,
5233                                      0, &dd_idx, NULL);
5234
5235         end_sector = bio_end_sector(align_bi);
5236         rcu_read_lock();
5237         rdev = rcu_dereference(conf->disks[dd_idx].replacement);
5238         if (!rdev || test_bit(Faulty, &rdev->flags) ||
5239             rdev->recovery_offset < end_sector) {
5240                 rdev = rcu_dereference(conf->disks[dd_idx].rdev);
5241                 if (rdev &&
5242                     (test_bit(Faulty, &rdev->flags) ||
5243                     !(test_bit(In_sync, &rdev->flags) ||
5244                       rdev->recovery_offset >= end_sector)))
5245                         rdev = NULL;
5246         }
5247
5248         if (r5c_big_stripe_cached(conf, align_bi->bi_iter.bi_sector)) {
5249                 rcu_read_unlock();
5250                 bio_put(align_bi);
5251                 return 0;
5252         }
5253
5254         if (rdev) {
5255                 sector_t first_bad;
5256                 int bad_sectors;
5257
5258                 atomic_inc(&rdev->nr_pending);
5259                 rcu_read_unlock();
5260                 raid_bio->bi_next = (void*)rdev;
5261                 bio_set_dev(align_bi, rdev->bdev);
5262
5263                 if (is_badblock(rdev, align_bi->bi_iter.bi_sector,
5264                                 bio_sectors(align_bi),
5265                                 &first_bad, &bad_sectors)) {
5266                         bio_put(align_bi);
5267                         rdev_dec_pending(rdev, mddev);
5268                         return 0;
5269                 }
5270
5271                 /* No reshape active, so we can trust rdev->data_offset */
5272                 align_bi->bi_iter.bi_sector += rdev->data_offset;
5273
5274                 spin_lock_irq(&conf->device_lock);
5275                 wait_event_lock_irq(conf->wait_for_quiescent,
5276                                     conf->quiesce == 0,
5277                                     conf->device_lock);
5278                 atomic_inc(&conf->active_aligned_reads);
5279                 spin_unlock_irq(&conf->device_lock);
5280
5281                 if (mddev->gendisk)
5282                         trace_block_bio_remap(align_bi->bi_disk->queue,
5283                                               align_bi, disk_devt(mddev->gendisk),
5284                                               raid_bio->bi_iter.bi_sector);
5285                 generic_make_request(align_bi);
5286                 return 1;
5287         } else {
5288                 rcu_read_unlock();
5289                 bio_put(align_bi);
5290                 return 0;
5291         }
5292 }
5293
5294 static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
5295 {
5296         struct bio *split;
5297         sector_t sector = raid_bio->bi_iter.bi_sector;
5298         unsigned chunk_sects = mddev->chunk_sectors;
5299         unsigned sectors = chunk_sects - (sector & (chunk_sects-1));
5300
5301         if (sectors < bio_sectors(raid_bio)) {
5302                 struct r5conf *conf = mddev->private;
5303                 split = bio_split(raid_bio, sectors, GFP_NOIO, &conf->bio_split);
5304                 bio_chain(split, raid_bio);
5305                 generic_make_request(raid_bio);
5306                 raid_bio = split;
5307         }
5308
5309         if (!raid5_read_one_chunk(mddev, raid_bio))
5310                 return raid_bio;
5311
5312         return NULL;
5313 }
5314
5315 /* __get_priority_stripe - get the next stripe to process
5316  *
5317  * Full stripe writes are allowed to pass preread active stripes up until
5318  * the bypass_threshold is exceeded.  In general the bypass_count
5319  * increments when the handle_list is handled before the hold_list; however, it
5320  * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
5321  * stripe with in flight i/o.  The bypass_count will be reset when the
5322  * head of the hold_list has changed, i.e. the head was promoted to the
5323  * handle_list.
5324  */
5325 static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group)
5326 {
5327         struct stripe_head *sh, *tmp;
5328         struct list_head *handle_list = NULL;
5329         struct r5worker_group *wg;
5330         bool second_try = !r5c_is_writeback(conf->log) &&
5331                 !r5l_log_disk_error(conf);
5332         bool try_loprio = test_bit(R5C_LOG_TIGHT, &conf->cache_state) ||
5333                 r5l_log_disk_error(conf);
5334
5335 again:
5336         wg = NULL;
5337         sh = NULL;
5338         if (conf->worker_cnt_per_group == 0) {
5339                 handle_list = try_loprio ? &conf->loprio_list :
5340                                         &conf->handle_list;
5341         } else if (group != ANY_GROUP) {
5342                 handle_list = try_loprio ? &conf->worker_groups[group].loprio_list :
5343                                 &conf->worker_groups[group].handle_list;
5344                 wg = &conf->worker_groups[group];
5345         } else {
5346                 int i;
5347                 for (i = 0; i < conf->group_cnt; i++) {
5348                         handle_list = try_loprio ? &conf->worker_groups[i].loprio_list :
5349                                 &conf->worker_groups[i].handle_list;
5350                         wg = &conf->worker_groups[i];
5351                         if (!list_empty(handle_list))
5352                                 break;
5353                 }
5354         }
5355
5356         pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
5357                   __func__,
5358                   list_empty(handle_list) ? "empty" : "busy",
5359                   list_empty(&conf->hold_list) ? "empty" : "busy",
5360                   atomic_read(&conf->pending_full_writes), conf->bypass_count);
5361
5362         if (!list_empty(handle_list)) {
5363                 sh = list_entry(handle_list->next, typeof(*sh), lru);
5364
5365                 if (list_empty(&conf->hold_list))
5366                         conf->bypass_count = 0;
5367                 else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
5368                         if (conf->hold_list.next == conf->last_hold)
5369                                 conf->bypass_count++;
5370                         else {
5371                                 conf->last_hold = conf->hold_list.next;
5372                                 conf->bypass_count -= conf->bypass_threshold;
5373                                 if (conf->bypass_count < 0)
5374                                         conf->bypass_count = 0;
5375                         }
5376                 }
5377         } else if (!list_empty(&conf->hold_list) &&
5378                    ((conf->bypass_threshold &&
5379                      conf->bypass_count > conf->bypass_threshold) ||
5380                     atomic_read(&conf->pending_full_writes) == 0)) {
5381
5382                 list_for_each_entry(tmp, &conf->hold_list,  lru) {
5383                         if (conf->worker_cnt_per_group == 0 ||
5384                             group == ANY_GROUP ||
5385                             !cpu_online(tmp->cpu) ||
5386                             cpu_to_group(tmp->cpu) == group) {
5387                                 sh = tmp;
5388                                 break;
5389                         }
5390                 }
5391
5392                 if (sh) {
5393                         conf->bypass_count -= conf->bypass_threshold;
5394                         if (conf->bypass_count < 0)
5395                                 conf->bypass_count = 0;
5396                 }
5397                 wg = NULL;
5398         }
5399
5400         if (!sh) {
5401                 if (second_try)
5402                         return NULL;
5403                 second_try = true;
5404                 try_loprio = !try_loprio;
5405                 goto again;
5406         }
5407
5408         if (wg) {
5409                 wg->stripes_cnt--;
5410                 sh->group = NULL;
5411         }
5412         list_del_init(&sh->lru);
5413         BUG_ON(atomic_inc_return(&sh->count) != 1);
5414         return sh;
5415 }
5416
5417 struct raid5_plug_cb {
5418         struct blk_plug_cb      cb;
5419         struct list_head        list;
5420         struct list_head        temp_inactive_list[NR_STRIPE_HASH_LOCKS];
5421 };
5422
5423 static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
5424 {
5425         struct raid5_plug_cb *cb = container_of(
5426                 blk_cb, struct raid5_plug_cb, cb);
5427         struct stripe_head *sh;
5428         struct mddev *mddev = cb->cb.data;
5429         struct r5conf *conf = mddev->private;
5430         int cnt = 0;
5431         int hash;
5432
5433         if (cb->list.next && !list_empty(&cb->list)) {
5434                 spin_lock_irq(&conf->device_lock);
5435                 while (!list_empty(&cb->list)) {
5436                         sh = list_first_entry(&cb->list, struct stripe_head, lru);
5437                         list_del_init(&sh->lru);
5438                         /*
5439                          * avoid race release_stripe_plug() sees
5440                          * STRIPE_ON_UNPLUG_LIST clear but the stripe
5441                          * is still in our list
5442                          */
5443                         smp_mb__before_atomic();
5444                         clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
5445                         /*
5446                          * STRIPE_ON_RELEASE_LIST could be set here. In that
5447                          * case, the count is always > 1 here
5448                          */
5449                         hash = sh->hash_lock_index;
5450                         __release_stripe(conf, sh, &cb->temp_inactive_list[hash]);
5451                         cnt++;
5452                 }
5453                 spin_unlock_irq(&conf->device_lock);
5454         }
5455         release_inactive_stripe_list(conf, cb->temp_inactive_list,
5456                                      NR_STRIPE_HASH_LOCKS);
5457         if (mddev->queue)
5458                 trace_block_unplug(mddev->queue, cnt, !from_schedule);
5459         kfree(cb);
5460 }
5461
5462 static void release_stripe_plug(struct mddev *mddev,
5463                                 struct stripe_head *sh)
5464 {
5465         struct blk_plug_cb *blk_cb = blk_check_plugged(
5466                 raid5_unplug, mddev,
5467                 sizeof(struct raid5_plug_cb));
5468         struct raid5_plug_cb *cb;
5469
5470         if (!blk_cb) {
5471                 raid5_release_stripe(sh);
5472                 return;
5473         }
5474
5475         cb = container_of(blk_cb, struct raid5_plug_cb, cb);
5476
5477         if (cb->list.next == NULL) {
5478                 int i;
5479                 INIT_LIST_HEAD(&cb->list);
5480                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
5481                         INIT_LIST_HEAD(cb->temp_inactive_list + i);
5482         }
5483
5484         if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
5485                 list_add_tail(&sh->lru, &cb->list);
5486         else
5487                 raid5_release_stripe(sh);
5488 }
5489
5490 static void make_discard_request(struct mddev *mddev, struct bio *bi)
5491 {
5492         struct r5conf *conf = mddev->private;
5493         sector_t logical_sector, last_sector;
5494         struct stripe_head *sh;
5495         int stripe_sectors;
5496
5497         if (mddev->reshape_position != MaxSector)
5498                 /* Skip discard while reshape is happening */
5499                 return;
5500
5501         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
5502         last_sector = bio_end_sector(bi);
5503
5504         bi->bi_next = NULL;
5505
5506         stripe_sectors = conf->chunk_sectors *
5507                 (conf->raid_disks - conf->max_degraded);
5508         logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
5509                                                stripe_sectors);
5510         sector_div(last_sector, stripe_sectors);
5511
5512         logical_sector *= conf->chunk_sectors;
5513         last_sector *= conf->chunk_sectors;
5514
5515         for (; logical_sector < last_sector;
5516              logical_sector += STRIPE_SECTORS) {
5517                 DEFINE_WAIT(w);
5518                 int d;
5519         again:
5520                 sh = raid5_get_active_stripe(conf, logical_sector, 0, 0, 0);
5521                 prepare_to_wait(&conf->wait_for_overlap, &w,
5522                                 TASK_UNINTERRUPTIBLE);
5523                 set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5524                 if (test_bit(STRIPE_SYNCING, &sh->state)) {
5525                         raid5_release_stripe(sh);
5526                         schedule();
5527                         goto again;
5528                 }
5529                 clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5530                 spin_lock_irq(&sh->stripe_lock);
5531                 for (d = 0; d < conf->raid_disks; d++) {
5532                         if (d == sh->pd_idx || d == sh->qd_idx)
5533                                 continue;
5534                         if (sh->dev[d].towrite || sh->dev[d].toread) {
5535                                 set_bit(R5_Overlap, &sh->dev[d].flags);
5536                                 spin_unlock_irq(&sh->stripe_lock);
5537                                 raid5_release_stripe(sh);
5538                                 schedule();
5539                                 goto again;
5540                         }
5541                 }
5542                 set_bit(STRIPE_DISCARD, &sh->state);
5543                 finish_wait(&conf->wait_for_overlap, &w);
5544                 sh->overwrite_disks = 0;
5545                 for (d = 0; d < conf->raid_disks; d++) {
5546                         if (d == sh->pd_idx || d == sh->qd_idx)
5547                                 continue;
5548                         sh->dev[d].towrite = bi;
5549                         set_bit(R5_OVERWRITE, &sh->dev[d].flags);
5550                         bio_inc_remaining(bi);
5551                         md_write_inc(mddev, bi);
5552                         sh->overwrite_disks++;
5553                 }
5554                 spin_unlock_irq(&sh->stripe_lock);
5555                 if (conf->mddev->bitmap) {
5556                         for (d = 0;
5557                              d < conf->raid_disks - conf->max_degraded;
5558                              d++)
5559                                 md_bitmap_startwrite(mddev->bitmap,
5560                                                      sh->sector,
5561                                                      STRIPE_SECTORS,
5562                                                      0);
5563                         sh->bm_seq = conf->seq_flush + 1;
5564                         set_bit(STRIPE_BIT_DELAY, &sh->state);
5565                 }
5566
5567                 set_bit(STRIPE_HANDLE, &sh->state);
5568                 clear_bit(STRIPE_DELAYED, &sh->state);
5569                 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5570                         atomic_inc(&conf->preread_active_stripes);
5571                 release_stripe_plug(mddev, sh);
5572         }
5573
5574         bio_endio(bi);
5575 }
5576
5577 static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
5578 {
5579         struct r5conf *conf = mddev->private;
5580         int dd_idx;
5581         sector_t new_sector;
5582         sector_t logical_sector, last_sector;
5583         struct stripe_head *sh;
5584         const int rw = bio_data_dir(bi);
5585         DEFINE_WAIT(w);
5586         bool do_prepare;
5587         bool do_flush = false;
5588
5589         if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
5590                 int ret = log_handle_flush_request(conf, bi);
5591
5592                 if (ret == 0)
5593                         return true;
5594                 if (ret == -ENODEV) {
5595                         md_flush_request(mddev, bi);
5596                         return true;
5597                 }
5598                 /* ret == -EAGAIN, fallback */
5599                 /*
5600                  * if r5l_handle_flush_request() didn't clear REQ_PREFLUSH,
5601                  * we need to flush journal device
5602                  */
5603                 do_flush = bi->bi_opf & REQ_PREFLUSH;
5604         }
5605
5606         if (!md_write_start(mddev, bi))
5607                 return false;
5608         /*
5609          * If array is degraded, better not do chunk aligned read because
5610          * later we might have to read it again in order to reconstruct
5611          * data on failed drives.
5612          */
5613         if (rw == READ && mddev->degraded == 0 &&
5614             mddev->reshape_position == MaxSector) {
5615                 bi = chunk_aligned_read(mddev, bi);
5616                 if (!bi)
5617                         return true;
5618         }
5619
5620         if (unlikely(bio_op(bi) == REQ_OP_DISCARD)) {
5621                 make_discard_request(mddev, bi);
5622                 md_write_end(mddev);
5623                 return true;
5624         }
5625
5626         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
5627         last_sector = bio_end_sector(bi);
5628         bi->bi_next = NULL;
5629
5630         prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
5631         for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
5632                 int previous;
5633                 int seq;
5634
5635                 do_prepare = false;
5636         retry:
5637                 seq = read_seqcount_begin(&conf->gen_lock);
5638                 previous = 0;
5639                 if (do_prepare)
5640                         prepare_to_wait(&conf->wait_for_overlap, &w,
5641                                 TASK_UNINTERRUPTIBLE);
5642                 if (unlikely(conf->reshape_progress != MaxSector)) {
5643                         /* spinlock is needed as reshape_progress may be
5644                          * 64bit on a 32bit platform, and so it might be
5645                          * possible to see a half-updated value
5646                          * Of course reshape_progress could change after
5647                          * the lock is dropped, so once we get a reference
5648                          * to the stripe that we think it is, we will have
5649                          * to check again.
5650                          */
5651                         spin_lock_irq(&conf->device_lock);
5652                         if (mddev->reshape_backwards
5653                             ? logical_sector < conf->reshape_progress
5654                             : logical_sector >= conf->reshape_progress) {
5655                                 previous = 1;
5656                         } else {
5657                                 if (mddev->reshape_backwards
5658                                     ? logical_sector < conf->reshape_safe
5659                                     : logical_sector >= conf->reshape_safe) {
5660                                         spin_unlock_irq(&conf->device_lock);
5661                                         schedule();
5662                                         do_prepare = true;
5663                                         goto retry;
5664                                 }
5665                         }
5666                         spin_unlock_irq(&conf->device_lock);
5667                 }
5668
5669                 new_sector = raid5_compute_sector(conf, logical_sector,
5670                                                   previous,
5671                                                   &dd_idx, NULL);
5672                 pr_debug("raid456: raid5_make_request, sector %llu logical %llu\n",
5673                         (unsigned long long)new_sector,
5674                         (unsigned long long)logical_sector);
5675
5676                 sh = raid5_get_active_stripe(conf, new_sector, previous,
5677                                        (bi->bi_opf & REQ_RAHEAD), 0);
5678                 if (sh) {
5679                         if (unlikely(previous)) {
5680                                 /* expansion might have moved on while waiting for a
5681                                  * stripe, so we must do the range check again.
5682                                  * Expansion could still move past after this
5683                                  * test, but as we are holding a reference to
5684                                  * 'sh', we know that if that happens,
5685                                  *  STRIPE_EXPANDING will get set and the expansion
5686                                  * won't proceed until we finish with the stripe.
5687                                  */
5688                                 int must_retry = 0;
5689                                 spin_lock_irq(&conf->device_lock);
5690                                 if (mddev->reshape_backwards
5691                                     ? logical_sector >= conf->reshape_progress
5692                                     : logical_sector < conf->reshape_progress)
5693                                         /* mismatch, need to try again */
5694                                         must_retry = 1;
5695                                 spin_unlock_irq(&conf->device_lock);
5696                                 if (must_retry) {
5697                                         raid5_release_stripe(sh);
5698                                         schedule();
5699                                         do_prepare = true;
5700                                         goto retry;
5701                                 }
5702                         }
5703                         if (read_seqcount_retry(&conf->gen_lock, seq)) {
5704                                 /* Might have got the wrong stripe_head
5705                                  * by accident
5706                                  */
5707                                 raid5_release_stripe(sh);
5708                                 goto retry;
5709                         }
5710
5711                         if (test_bit(STRIPE_EXPANDING, &sh->state) ||
5712                             !add_stripe_bio(sh, bi, dd_idx, rw, previous)) {
5713                                 /* Stripe is busy expanding or
5714                                  * add failed due to overlap.  Flush everything
5715                                  * and wait a while
5716                                  */
5717                                 md_wakeup_thread(mddev->thread);
5718                                 raid5_release_stripe(sh);
5719                                 schedule();
5720                                 do_prepare = true;
5721                                 goto retry;
5722                         }
5723                         if (do_flush) {
5724                                 set_bit(STRIPE_R5C_PREFLUSH, &sh->state);
5725                                 /* we only need flush for one stripe */
5726                                 do_flush = false;
5727                         }
5728
5729                         if (!sh->batch_head)
5730                                 set_bit(STRIPE_HANDLE, &sh->state);
5731                         clear_bit(STRIPE_DELAYED, &sh->state);
5732                         if ((!sh->batch_head || sh == sh->batch_head) &&
5733                             (bi->bi_opf & REQ_SYNC) &&
5734                             !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5735                                 atomic_inc(&conf->preread_active_stripes);
5736                         release_stripe_plug(mddev, sh);
5737                 } else {
5738                         /* cannot get stripe for read-ahead, just give-up */
5739                         bi->bi_status = BLK_STS_IOERR;
5740                         break;
5741                 }
5742         }
5743         finish_wait(&conf->wait_for_overlap, &w);
5744
5745         if (rw == WRITE)
5746                 md_write_end(mddev);
5747         bio_endio(bi);
5748         return true;
5749 }
5750
5751 static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
5752
5753 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
5754 {
5755         /* reshaping is quite different to recovery/resync so it is
5756          * handled quite separately ... here.
5757          *
5758          * On each call to sync_request, we gather one chunk worth of
5759          * destination stripes and flag them as expanding.
5760          * Then we find all the source stripes and request reads.
5761          * As the reads complete, handle_stripe will copy the data
5762          * into the destination stripe and release that stripe.
5763          */
5764         struct r5conf *conf = mddev->private;
5765         struct stripe_head *sh;
5766         struct md_rdev *rdev;
5767         sector_t first_sector, last_sector;
5768         int raid_disks = conf->previous_raid_disks;
5769         int data_disks = raid_disks - conf->max_degraded;
5770         int new_data_disks = conf->raid_disks - conf->max_degraded;
5771         int i;
5772         int dd_idx;
5773         sector_t writepos, readpos, safepos;
5774         sector_t stripe_addr;
5775         int reshape_sectors;
5776         struct list_head stripes;
5777         sector_t retn;
5778
5779         if (sector_nr == 0) {
5780                 /* If restarting in the middle, skip the initial sectors */
5781                 if (mddev->reshape_backwards &&
5782                     conf->reshape_progress < raid5_size(mddev, 0, 0)) {
5783                         sector_nr = raid5_size(mddev, 0, 0)
5784                                 - conf->reshape_progress;
5785                 } else if (mddev->reshape_backwards &&
5786                            conf->reshape_progress == MaxSector) {
5787                         /* shouldn't happen, but just in case, finish up.*/
5788                         sector_nr = MaxSector;
5789                 } else if (!mddev->reshape_backwards &&
5790                            conf->reshape_progress > 0)
5791                         sector_nr = conf->reshape_progress;
5792                 sector_div(sector_nr, new_data_disks);
5793                 if (sector_nr) {
5794                         mddev->curr_resync_completed = sector_nr;
5795                         sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5796                         *skipped = 1;
5797                         retn = sector_nr;
5798                         goto finish;
5799                 }
5800         }
5801
5802         /* We need to process a full chunk at a time.
5803          * If old and new chunk sizes differ, we need to process the
5804          * largest of these
5805          */
5806
5807         reshape_sectors = max(conf->chunk_sectors, conf->prev_chunk_sectors);
5808
5809         /* We update the metadata at least every 10 seconds, or when
5810          * the data about to be copied would over-write the source of
5811          * the data at the front of the range.  i.e. one new_stripe
5812          * along from reshape_progress new_maps to after where
5813          * reshape_safe old_maps to
5814          */
5815         writepos = conf->reshape_progress;
5816         sector_div(writepos, new_data_disks);
5817         readpos = conf->reshape_progress;
5818         sector_div(readpos, data_disks);
5819         safepos = conf->reshape_safe;
5820         sector_div(safepos, data_disks);
5821         if (mddev->reshape_backwards) {
5822                 BUG_ON(writepos < reshape_sectors);
5823                 writepos -= reshape_sectors;
5824                 readpos += reshape_sectors;
5825                 safepos += reshape_sectors;
5826         } else {
5827                 writepos += reshape_sectors;
5828                 /* readpos and safepos are worst-case calculations.
5829                  * A negative number is overly pessimistic, and causes
5830                  * obvious problems for unsigned storage.  So clip to 0.
5831                  */
5832                 readpos -= min_t(sector_t, reshape_sectors, readpos);
5833                 safepos -= min_t(sector_t, reshape_sectors, safepos);
5834         }
5835
5836         /* Having calculated the 'writepos' possibly use it
5837          * to set 'stripe_addr' which is where we will write to.
5838          */
5839         if (mddev->reshape_backwards) {
5840                 BUG_ON(conf->reshape_progress == 0);
5841                 stripe_addr = writepos;
5842                 BUG_ON((mddev->dev_sectors &
5843                         ~((sector_t)reshape_sectors - 1))
5844                        - reshape_sectors - stripe_addr
5845                        != sector_nr);
5846         } else {
5847                 BUG_ON(writepos != sector_nr + reshape_sectors);
5848                 stripe_addr = sector_nr;
5849         }
5850
5851         /* 'writepos' is the most advanced device address we might write.
5852          * 'readpos' is the least advanced device address we might read.
5853          * 'safepos' is the least address recorded in the metadata as having
5854          *     been reshaped.
5855          * If there is a min_offset_diff, these are adjusted either by
5856          * increasing the safepos/readpos if diff is negative, or
5857          * increasing writepos if diff is positive.
5858          * If 'readpos' is then behind 'writepos', there is no way that we can
5859          * ensure safety in the face of a crash - that must be done by userspace
5860          * making a backup of the data.  So in that case there is no particular
5861          * rush to update metadata.
5862          * Otherwise if 'safepos' is behind 'writepos', then we really need to
5863          * update the metadata to advance 'safepos' to match 'readpos' so that
5864          * we can be safe in the event of a crash.
5865          * So we insist on updating metadata if safepos is behind writepos and
5866          * readpos is beyond writepos.
5867          * In any case, update the metadata every 10 seconds.
5868          * Maybe that number should be configurable, but I'm not sure it is
5869          * worth it.... maybe it could be a multiple of safemode_delay???
5870          */
5871         if (conf->min_offset_diff < 0) {
5872                 safepos += -conf->min_offset_diff;
5873                 readpos += -conf->min_offset_diff;
5874         } else
5875                 writepos += conf->min_offset_diff;
5876
5877         if ((mddev->reshape_backwards
5878              ? (safepos > writepos && readpos < writepos)
5879              : (safepos < writepos && readpos > writepos)) ||
5880             time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
5881                 /* Cannot proceed until we've updated the superblock... */
5882                 wait_event(conf->wait_for_overlap,
5883                            atomic_read(&conf->reshape_stripes)==0
5884                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5885                 if (atomic_read(&conf->reshape_stripes) != 0)
5886                         return 0;
5887                 mddev->reshape_position = conf->reshape_progress;
5888                 mddev->curr_resync_completed = sector_nr;
5889                 if (!mddev->reshape_backwards)
5890                         /* Can update recovery_offset */
5891                         rdev_for_each(rdev, mddev)
5892                                 if (rdev->raid_disk >= 0 &&
5893                                     !test_bit(Journal, &rdev->flags) &&
5894                                     !test_bit(In_sync, &rdev->flags) &&
5895                                     rdev->recovery_offset < sector_nr)
5896                                         rdev->recovery_offset = sector_nr;
5897
5898                 conf->reshape_checkpoint = jiffies;
5899                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
5900                 md_wakeup_thread(mddev->thread);
5901                 wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
5902                            test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5903                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5904                         return 0;
5905                 spin_lock_irq(&conf->device_lock);
5906                 conf->reshape_safe = mddev->reshape_position;
5907                 spin_unlock_irq(&conf->device_lock);
5908                 wake_up(&conf->wait_for_overlap);
5909                 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5910         }
5911
5912         INIT_LIST_HEAD(&stripes);
5913         for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
5914                 int j;
5915                 int skipped_disk = 0;
5916                 sh = raid5_get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
5917                 set_bit(STRIPE_EXPANDING, &sh->state);
5918                 atomic_inc(&conf->reshape_stripes);
5919                 /* If any of this stripe is beyond the end of the old
5920                  * array, then we need to zero those blocks
5921                  */
5922                 for (j=sh->disks; j--;) {
5923                         sector_t s;
5924                         if (j == sh->pd_idx)
5925                                 continue;
5926                         if (conf->level == 6 &&
5927                             j == sh->qd_idx)
5928                                 continue;
5929                         s = raid5_compute_blocknr(sh, j, 0);
5930                         if (s < raid5_size(mddev, 0, 0)) {
5931                                 skipped_disk = 1;
5932                                 continue;
5933                         }
5934                         memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE);
5935                         set_bit(R5_Expanded, &sh->dev[j].flags);
5936                         set_bit(R5_UPTODATE, &sh->dev[j].flags);
5937                 }
5938                 if (!skipped_disk) {
5939                         set_bit(STRIPE_EXPAND_READY, &sh->state);
5940                         set_bit(STRIPE_HANDLE, &sh->state);
5941                 }
5942                 list_add(&sh->lru, &stripes);
5943         }
5944         spin_lock_irq(&conf->device_lock);
5945         if (mddev->reshape_backwards)
5946                 conf->reshape_progress -= reshape_sectors * new_data_disks;
5947         else
5948                 conf->reshape_progress += reshape_sectors * new_data_disks;
5949         spin_unlock_irq(&conf->device_lock);
5950         /* Ok, those stripe are ready. We can start scheduling
5951          * reads on the source stripes.
5952          * The source stripes are determined by mapping the first and last
5953          * block on the destination stripes.
5954          */
5955         first_sector =
5956                 raid5_compute_sector(conf, stripe_addr*(new_data_disks),
5957                                      1, &dd_idx, NULL);
5958         last_sector =
5959                 raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
5960                                             * new_data_disks - 1),
5961                                      1, &dd_idx, NULL);
5962         if (last_sector >= mddev->dev_sectors)
5963                 last_sector = mddev->dev_sectors - 1;
5964         while (first_sector <= last_sector) {
5965                 sh = raid5_get_active_stripe(conf, first_sector, 1, 0, 1);
5966                 set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
5967                 set_bit(STRIPE_HANDLE, &sh->state);
5968                 raid5_release_stripe(sh);
5969                 first_sector += STRIPE_SECTORS;
5970         }
5971         /* Now that the sources are clearly marked, we can release
5972          * the destination stripes
5973          */
5974         while (!list_empty(&stripes)) {
5975                 sh = list_entry(stripes.next, struct stripe_head, lru);
5976                 list_del_init(&sh->lru);
5977                 raid5_release_stripe(sh);
5978         }
5979         /* If this takes us to the resync_max point where we have to pause,
5980          * then we need to write out the superblock.
5981          */
5982         sector_nr += reshape_sectors;
5983         retn = reshape_sectors;
5984 finish:
5985         if (mddev->curr_resync_completed > mddev->resync_max ||
5986             (sector_nr - mddev->curr_resync_completed) * 2
5987             >= mddev->resync_max - mddev->curr_resync_completed) {
5988                 /* Cannot proceed until we've updated the superblock... */
5989                 wait_event(conf->wait_for_overlap,
5990                            atomic_read(&conf->reshape_stripes) == 0
5991                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5992                 if (atomic_read(&conf->reshape_stripes) != 0)
5993                         goto ret;
5994                 mddev->reshape_position = conf->reshape_progress;
5995                 mddev->curr_resync_completed = sector_nr;
5996                 if (!mddev->reshape_backwards)
5997                         /* Can update recovery_offset */
5998                         rdev_for_each(rdev, mddev)
5999                                 if (rdev->raid_disk >= 0 &&
6000                                     !test_bit(Journal, &rdev->flags) &&
6001                                     !test_bit(In_sync, &rdev->flags) &&
6002                                     rdev->recovery_offset < sector_nr)
6003                                         rdev->recovery_offset = sector_nr;
6004                 conf->reshape_checkpoint = jiffies;
6005                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
6006                 md_wakeup_thread(mddev->thread);
6007                 wait_event(mddev->sb_wait,
6008                            !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)
6009                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6010                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6011                         goto ret;
6012                 spin_lock_irq(&conf->device_lock);
6013                 conf->reshape_safe = mddev->reshape_position;
6014                 spin_unlock_irq(&conf->device_lock);
6015                 wake_up(&conf->wait_for_overlap);
6016                 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
6017         }
6018 ret:
6019         return retn;
6020 }
6021
6022 static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_nr,
6023                                           int *skipped)
6024 {
6025         struct r5conf *conf = mddev->private;
6026         struct stripe_head *sh;
6027         sector_t max_sector = mddev->dev_sectors;
6028         sector_t sync_blocks;
6029         int still_degraded = 0;
6030         int i;
6031
6032         if (sector_nr >= max_sector) {
6033                 /* just being told to finish up .. nothing much to do */
6034
6035                 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
6036                         end_reshape(conf);
6037                         return 0;
6038                 }
6039
6040                 if (mddev->curr_resync < max_sector) /* aborted */
6041                         md_bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
6042                                            &sync_blocks, 1);
6043                 else /* completed sync */
6044                         conf->fullsync = 0;
6045                 md_bitmap_close_sync(mddev->bitmap);
6046
6047                 return 0;
6048         }
6049
6050         /* Allow raid5_quiesce to complete */
6051         wait_event(conf->wait_for_overlap, conf->quiesce != 2);
6052
6053         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6054                 return reshape_request(mddev, sector_nr, skipped);
6055
6056         /* No need to check resync_max as we never do more than one
6057          * stripe, and as resync_max will always be on a chunk boundary,
6058          * if the check in md_do_sync didn't fire, there is no chance
6059          * of overstepping resync_max here
6060          */
6061
6062         /* if there is too many failed drives and we are trying
6063          * to resync, then assert that we are finished, because there is
6064          * nothing we can do.
6065          */
6066         if (mddev->degraded >= conf->max_degraded &&
6067             test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
6068                 sector_t rv = mddev->dev_sectors - sector_nr;
6069                 *skipped = 1;
6070                 return rv;
6071         }
6072         if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
6073             !conf->fullsync &&
6074             !md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
6075             sync_blocks >= STRIPE_SECTORS) {
6076                 /* we can skip this block, and probably more */
6077                 sync_blocks /= STRIPE_SECTORS;
6078                 *skipped = 1;
6079                 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
6080         }
6081
6082         md_bitmap_cond_end_sync(mddev->bitmap, sector_nr, false);
6083
6084         sh = raid5_get_active_stripe(conf, sector_nr, 0, 1, 0);
6085         if (sh == NULL) {
6086                 sh = raid5_get_active_stripe(conf, sector_nr, 0, 0, 0);
6087                 /* make sure we don't swamp the stripe cache if someone else
6088                  * is trying to get access
6089                  */
6090                 schedule_timeout_uninterruptible(1);
6091         }
6092         /* Need to check if array will still be degraded after recovery/resync
6093          * Note in case of > 1 drive failures it's possible we're rebuilding
6094          * one drive while leaving another faulty drive in array.
6095          */
6096         rcu_read_lock();
6097         for (i = 0; i < conf->raid_disks; i++) {
6098                 struct md_rdev *rdev = READ_ONCE(conf->disks[i].rdev);
6099
6100                 if (rdev == NULL || test_bit(Faulty, &rdev->flags))
6101                         still_degraded = 1;
6102         }
6103         rcu_read_unlock();
6104
6105         md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
6106
6107         set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
6108         set_bit(STRIPE_HANDLE, &sh->state);
6109
6110         raid5_release_stripe(sh);
6111
6112         return STRIPE_SECTORS;
6113 }
6114
6115 static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio,
6116                                unsigned int offset)
6117 {
6118         /* We may not be able to submit a whole bio at once as there
6119          * may not be enough stripe_heads available.
6120          * We cannot pre-allocate enough stripe_heads as we may need
6121          * more than exist in the cache (if we allow ever large chunks).
6122          * So we do one stripe head at a time and record in
6123          * ->bi_hw_segments how many have been done.
6124          *
6125          * We *know* that this entire raid_bio is in one chunk, so
6126          * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
6127          */
6128         struct stripe_head *sh;
6129         int dd_idx;
6130         sector_t sector, logical_sector, last_sector;
6131         int scnt = 0;
6132         int handled = 0;
6133
6134         logical_sector = raid_bio->bi_iter.bi_sector &
6135                 ~((sector_t)STRIPE_SECTORS-1);
6136         sector = raid5_compute_sector(conf, logical_sector,
6137                                       0, &dd_idx, NULL);
6138         last_sector = bio_end_sector(raid_bio);
6139
6140         for (; logical_sector < last_sector;
6141              logical_sector += STRIPE_SECTORS,
6142                      sector += STRIPE_SECTORS,
6143                      scnt++) {
6144
6145                 if (scnt < offset)
6146                         /* already done this stripe */
6147                         continue;
6148
6149                 sh = raid5_get_active_stripe(conf, sector, 0, 1, 1);
6150
6151                 if (!sh) {
6152                         /* failed to get a stripe - must wait */
6153                         conf->retry_read_aligned = raid_bio;
6154                         conf->retry_read_offset = scnt;
6155                         return handled;
6156                 }
6157
6158                 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0, 0)) {
6159                         raid5_release_stripe(sh);
6160                         conf->retry_read_aligned = raid_bio;
6161                         conf->retry_read_offset = scnt;
6162                         return handled;
6163                 }
6164
6165                 set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
6166                 handle_stripe(sh);
6167                 raid5_release_stripe(sh);
6168                 handled++;
6169         }
6170
6171         bio_endio(raid_bio);
6172
6173         if (atomic_dec_and_test(&conf->active_aligned_reads))
6174                 wake_up(&conf->wait_for_quiescent);
6175         return handled;
6176 }
6177
6178 static int handle_active_stripes(struct r5conf *conf, int group,
6179                                  struct r5worker *worker,
6180                                  struct list_head *temp_inactive_list)
6181                 __releases(&conf->device_lock)
6182                 __acquires(&conf->device_lock)
6183 {
6184         struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
6185         int i, batch_size = 0, hash;
6186         bool release_inactive = false;
6187
6188         while (batch_size < MAX_STRIPE_BATCH &&
6189                         (sh = __get_priority_stripe(conf, group)) != NULL)
6190                 batch[batch_size++] = sh;
6191
6192         if (batch_size == 0) {
6193                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6194                         if (!list_empty(temp_inactive_list + i))
6195                                 break;
6196                 if (i == NR_STRIPE_HASH_LOCKS) {
6197                         spin_unlock_irq(&conf->device_lock);
6198                         log_flush_stripe_to_raid(conf);
6199                         spin_lock_irq(&conf->device_lock);
6200                         return batch_size;
6201                 }
6202                 release_inactive = true;
6203         }
6204         spin_unlock_irq(&conf->device_lock);
6205
6206         release_inactive_stripe_list(conf, temp_inactive_list,
6207                                      NR_STRIPE_HASH_LOCKS);
6208
6209         r5l_flush_stripe_to_raid(conf->log);
6210         if (release_inactive) {
6211                 spin_lock_irq(&conf->device_lock);
6212                 return 0;
6213         }
6214
6215         for (i = 0; i < batch_size; i++)
6216                 handle_stripe(batch[i]);
6217         log_write_stripe_run(conf);
6218
6219         cond_resched();
6220
6221         spin_lock_irq(&conf->device_lock);
6222         for (i = 0; i < batch_size; i++) {
6223                 hash = batch[i]->hash_lock_index;
6224                 __release_stripe(conf, batch[i], &temp_inactive_list[hash]);
6225         }
6226         return batch_size;
6227 }
6228
6229 static void raid5_do_work(struct work_struct *work)
6230 {
6231         struct r5worker *worker = container_of(work, struct r5worker, work);
6232         struct r5worker_group *group = worker->group;
6233         struct r5conf *conf = group->conf;
6234         struct mddev *mddev = conf->mddev;
6235         int group_id = group - conf->worker_groups;
6236         int handled;
6237         struct blk_plug plug;
6238
6239         pr_debug("+++ raid5worker active\n");
6240
6241         blk_start_plug(&plug);
6242         handled = 0;
6243         spin_lock_irq(&conf->device_lock);
6244         while (1) {
6245                 int batch_size, released;
6246
6247                 released = release_stripe_list(conf, worker->temp_inactive_list);
6248
6249                 batch_size = handle_active_stripes(conf, group_id, worker,
6250                                                    worker->temp_inactive_list);
6251                 worker->working = false;
6252                 if (!batch_size && !released)
6253                         break;
6254                 handled += batch_size;
6255                 wait_event_lock_irq(mddev->sb_wait,
6256                         !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
6257                         conf->device_lock);
6258         }
6259         pr_debug("%d stripes handled\n", handled);
6260
6261         spin_unlock_irq(&conf->device_lock);
6262
6263         flush_deferred_bios(conf);
6264
6265         r5l_flush_stripe_to_raid(conf->log);
6266
6267         async_tx_issue_pending_all();
6268         blk_finish_plug(&plug);
6269
6270         pr_debug("--- raid5worker inactive\n");
6271 }
6272
6273 /*
6274  * This is our raid5 kernel thread.
6275  *
6276  * We scan the hash table for stripes which can be handled now.
6277  * During the scan, completed stripes are saved for us by the interrupt
6278  * handler, so that they will not have to wait for our next wakeup.
6279  */
6280 static void raid5d(struct md_thread *thread)
6281 {
6282         struct mddev *mddev = thread->mddev;
6283         struct r5conf *conf = mddev->private;
6284         int handled;
6285         struct blk_plug plug;
6286
6287         pr_debug("+++ raid5d active\n");
6288
6289         md_check_recovery(mddev);
6290
6291         blk_start_plug(&plug);
6292         handled = 0;
6293         spin_lock_irq(&conf->device_lock);
6294         while (1) {
6295                 struct bio *bio;
6296                 int batch_size, released;
6297                 unsigned int offset;
6298
6299                 released = release_stripe_list(conf, conf->temp_inactive_list);
6300                 if (released)
6301                         clear_bit(R5_DID_ALLOC, &conf->cache_state);
6302
6303                 if (
6304                     !list_empty(&conf->bitmap_list)) {
6305                         /* Now is a good time to flush some bitmap updates */
6306                         conf->seq_flush++;
6307                         spin_unlock_irq(&conf->device_lock);
6308                         md_bitmap_unplug(mddev->bitmap);
6309                         spin_lock_irq(&conf->device_lock);
6310                         conf->seq_write = conf->seq_flush;
6311                         activate_bit_delay(conf, conf->temp_inactive_list);
6312                 }
6313                 raid5_activate_delayed(conf);
6314
6315                 while ((bio = remove_bio_from_retry(conf, &offset))) {
6316                         int ok;
6317                         spin_unlock_irq(&conf->device_lock);
6318                         ok = retry_aligned_read(conf, bio, offset);
6319                         spin_lock_irq(&conf->device_lock);
6320                         if (!ok)
6321                                 break;
6322                         handled++;
6323                 }
6324
6325                 batch_size = handle_active_stripes(conf, ANY_GROUP, NULL,
6326                                                    conf->temp_inactive_list);
6327                 if (!batch_size && !released)
6328                         break;
6329                 handled += batch_size;
6330
6331                 if (mddev->sb_flags & ~(1 << MD_SB_CHANGE_PENDING)) {
6332                         spin_unlock_irq(&conf->device_lock);
6333                         md_check_recovery(mddev);
6334                         spin_lock_irq(&conf->device_lock);
6335                 }
6336         }
6337         pr_debug("%d stripes handled\n", handled);
6338
6339         spin_unlock_irq(&conf->device_lock);
6340         if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state) &&
6341             mutex_trylock(&conf->cache_size_mutex)) {
6342                 grow_one_stripe(conf, __GFP_NOWARN);
6343                 /* Set flag even if allocation failed.  This helps
6344                  * slow down allocation requests when mem is short
6345                  */
6346                 set_bit(R5_DID_ALLOC, &conf->cache_state);
6347                 mutex_unlock(&conf->cache_size_mutex);
6348         }
6349
6350         flush_deferred_bios(conf);
6351
6352         r5l_flush_stripe_to_raid(conf->log);
6353
6354         async_tx_issue_pending_all();
6355         blk_finish_plug(&plug);
6356
6357         pr_debug("--- raid5d inactive\n");
6358 }
6359
6360 static ssize_t
6361 raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
6362 {
6363         struct r5conf *conf;
6364         int ret = 0;
6365         spin_lock(&mddev->lock);
6366         conf = mddev->private;
6367         if (conf)
6368                 ret = sprintf(page, "%d\n", conf->min_nr_stripes);
6369         spin_unlock(&mddev->lock);
6370         return ret;
6371 }
6372
6373 int
6374 raid5_set_cache_size(struct mddev *mddev, int size)
6375 {
6376         int result = 0;
6377         struct r5conf *conf = mddev->private;
6378
6379         if (size <= 16 || size > 32768)
6380                 return -EINVAL;
6381
6382         conf->min_nr_stripes = size;
6383         mutex_lock(&conf->cache_size_mutex);
6384         while (size < conf->max_nr_stripes &&
6385                drop_one_stripe(conf))
6386                 ;
6387         mutex_unlock(&conf->cache_size_mutex);
6388
6389         md_allow_write(mddev);
6390
6391         mutex_lock(&conf->cache_size_mutex);
6392         while (size > conf->max_nr_stripes)
6393                 if (!grow_one_stripe(conf, GFP_KERNEL)) {
6394                         conf->min_nr_stripes = conf->max_nr_stripes;
6395                         result = -ENOMEM;
6396                         break;
6397                 }
6398         mutex_unlock(&conf->cache_size_mutex);
6399
6400         return result;
6401 }
6402 EXPORT_SYMBOL(raid5_set_cache_size);
6403
6404 static ssize_t
6405 raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
6406 {
6407         struct r5conf *conf;
6408         unsigned long new;
6409         int err;
6410
6411         if (len >= PAGE_SIZE)
6412                 return -EINVAL;
6413         if (kstrtoul(page, 10, &new))
6414                 return -EINVAL;
6415         err = mddev_lock(mddev);
6416         if (err)
6417                 return err;
6418         conf = mddev->private;
6419         if (!conf)
6420                 err = -ENODEV;
6421         else
6422                 err = raid5_set_cache_size(mddev, new);
6423         mddev_unlock(mddev);
6424
6425         return err ?: len;
6426 }
6427
6428 static struct md_sysfs_entry
6429 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
6430                                 raid5_show_stripe_cache_size,
6431                                 raid5_store_stripe_cache_size);
6432
6433 static ssize_t
6434 raid5_show_rmw_level(struct mddev  *mddev, char *page)
6435 {
6436         struct r5conf *conf = mddev->private;
6437         if (conf)
6438                 return sprintf(page, "%d\n", conf->rmw_level);
6439         else
6440                 return 0;
6441 }
6442
6443 static ssize_t
6444 raid5_store_rmw_level(struct mddev  *mddev, const char *page, size_t len)
6445 {
6446         struct r5conf *conf = mddev->private;
6447         unsigned long new;
6448
6449         if (!conf)
6450                 return -ENODEV;
6451
6452         if (len >= PAGE_SIZE)
6453                 return -EINVAL;
6454
6455         if (kstrtoul(page, 10, &new))
6456                 return -EINVAL;
6457
6458         if (new != PARITY_DISABLE_RMW && !raid6_call.xor_syndrome)
6459                 return -EINVAL;
6460
6461         if (new != PARITY_DISABLE_RMW &&
6462             new != PARITY_ENABLE_RMW &&
6463             new != PARITY_PREFER_RMW)
6464                 return -EINVAL;
6465
6466         conf->rmw_level = new;
6467         return len;
6468 }
6469
6470 static struct md_sysfs_entry
6471 raid5_rmw_level = __ATTR(rmw_level, S_IRUGO | S_IWUSR,
6472                          raid5_show_rmw_level,
6473                          raid5_store_rmw_level);
6474
6475
6476 static ssize_t
6477 raid5_show_preread_threshold(struct mddev *mddev, char *page)
6478 {
6479         struct r5conf *conf;
6480         int ret = 0;
6481         spin_lock(&mddev->lock);
6482         conf = mddev->private;
6483         if (conf)
6484                 ret = sprintf(page, "%d\n", conf->bypass_threshold);
6485         spin_unlock(&mddev->lock);
6486         return ret;
6487 }
6488
6489 static ssize_t
6490 raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
6491 {
6492         struct r5conf *conf;
6493         unsigned long new;
6494         int err;
6495
6496         if (len >= PAGE_SIZE)
6497                 return -EINVAL;
6498         if (kstrtoul(page, 10, &new))
6499                 return -EINVAL;
6500
6501         err = mddev_lock(mddev);
6502         if (err)
6503                 return err;
6504         conf = mddev->private;
6505         if (!conf)
6506                 err = -ENODEV;
6507         else if (new > conf->min_nr_stripes)
6508                 err = -EINVAL;
6509         else
6510                 conf->bypass_threshold = new;
6511         mddev_unlock(mddev);
6512         return err ?: len;
6513 }
6514
6515 static struct md_sysfs_entry
6516 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
6517                                         S_IRUGO | S_IWUSR,
6518                                         raid5_show_preread_threshold,
6519                                         raid5_store_preread_threshold);
6520
6521 static ssize_t
6522 raid5_show_skip_copy(struct mddev *mddev, char *page)
6523 {
6524         struct r5conf *conf;
6525         int ret = 0;
6526         spin_lock(&mddev->lock);
6527         conf = mddev->private;
6528         if (conf)
6529                 ret = sprintf(page, "%d\n", conf->skip_copy);
6530         spin_unlock(&mddev->lock);
6531         return ret;
6532 }
6533
6534 static ssize_t
6535 raid5_store_skip_copy(struct mddev *mddev, const char *page, size_t len)
6536 {
6537         struct r5conf *conf;
6538         unsigned long new;
6539         int err;
6540
6541         if (len >= PAGE_SIZE)
6542                 return -EINVAL;
6543         if (kstrtoul(page, 10, &new))
6544                 return -EINVAL;
6545         new = !!new;
6546
6547         err = mddev_lock(mddev);
6548         if (err)
6549                 return err;
6550         conf = mddev->private;
6551         if (!conf)
6552                 err = -ENODEV;
6553         else if (new != conf->skip_copy) {
6554                 mddev_suspend(mddev);
6555                 conf->skip_copy = new;
6556                 if (new)
6557                         mddev->queue->backing_dev_info->capabilities |=
6558                                 BDI_CAP_STABLE_WRITES;
6559                 else
6560                         mddev->queue->backing_dev_info->capabilities &=
6561                                 ~BDI_CAP_STABLE_WRITES;
6562                 mddev_resume(mddev);
6563         }
6564         mddev_unlock(mddev);
6565         return err ?: len;
6566 }
6567
6568 static struct md_sysfs_entry
6569 raid5_skip_copy = __ATTR(skip_copy, S_IRUGO | S_IWUSR,
6570                                         raid5_show_skip_copy,
6571                                         raid5_store_skip_copy);
6572
6573 static ssize_t
6574 stripe_cache_active_show(struct mddev *mddev, char *page)
6575 {
6576         struct r5conf *conf = mddev->private;
6577         if (conf)
6578                 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
6579         else
6580                 return 0;
6581 }
6582
6583 static struct md_sysfs_entry
6584 raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
6585
6586 static ssize_t
6587 raid5_show_group_thread_cnt(struct mddev *mddev, char *page)
6588 {
6589         struct r5conf *conf;
6590         int ret = 0;
6591         spin_lock(&mddev->lock);
6592         conf = mddev->private;
6593         if (conf)
6594                 ret = sprintf(page, "%d\n", conf->worker_cnt_per_group);
6595         spin_unlock(&mddev->lock);
6596         return ret;
6597 }
6598
6599 static int alloc_thread_groups(struct r5conf *conf, int cnt,
6600                                int *group_cnt,
6601                                int *worker_cnt_per_group,
6602                                struct r5worker_group **worker_groups);
6603 static ssize_t
6604 raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
6605 {
6606         struct r5conf *conf;
6607         unsigned int new;
6608         int err;
6609         struct r5worker_group *new_groups, *old_groups;
6610         int group_cnt, worker_cnt_per_group;
6611
6612         if (len >= PAGE_SIZE)
6613                 return -EINVAL;
6614         if (kstrtouint(page, 10, &new))
6615                 return -EINVAL;
6616         /* 8192 should be big enough */
6617         if (new > 8192)
6618                 return -EINVAL;
6619
6620         err = mddev_lock(mddev);
6621         if (err)
6622                 return err;
6623         conf = mddev->private;
6624         if (!conf)
6625                 err = -ENODEV;
6626         else if (new != conf->worker_cnt_per_group) {
6627                 mddev_suspend(mddev);
6628
6629                 old_groups = conf->worker_groups;
6630                 if (old_groups)
6631                         flush_workqueue(raid5_wq);
6632
6633                 err = alloc_thread_groups(conf, new,
6634                                           &group_cnt, &worker_cnt_per_group,
6635                                           &new_groups);
6636                 if (!err) {
6637                         spin_lock_irq(&conf->device_lock);
6638                         conf->group_cnt = group_cnt;
6639                         conf->worker_cnt_per_group = worker_cnt_per_group;
6640                         conf->worker_groups = new_groups;
6641                         spin_unlock_irq(&conf->device_lock);
6642
6643                         if (old_groups)
6644                                 kfree(old_groups[0].workers);
6645                         kfree(old_groups);
6646                 }
6647                 mddev_resume(mddev);
6648         }
6649         mddev_unlock(mddev);
6650
6651         return err ?: len;
6652 }
6653
6654 static struct md_sysfs_entry
6655 raid5_group_thread_cnt = __ATTR(group_thread_cnt, S_IRUGO | S_IWUSR,
6656                                 raid5_show_group_thread_cnt,
6657                                 raid5_store_group_thread_cnt);
6658
6659 static struct attribute *raid5_attrs[] =  {
6660         &raid5_stripecache_size.attr,
6661         &raid5_stripecache_active.attr,
6662         &raid5_preread_bypass_threshold.attr,
6663         &raid5_group_thread_cnt.attr,
6664         &raid5_skip_copy.attr,
6665         &raid5_rmw_level.attr,
6666         &r5c_journal_mode.attr,
6667         &ppl_write_hint.attr,
6668         NULL,
6669 };
6670 static struct attribute_group raid5_attrs_group = {
6671         .name = NULL,
6672         .attrs = raid5_attrs,
6673 };
6674
6675 static int alloc_thread_groups(struct r5conf *conf, int cnt,
6676                                int *group_cnt,
6677                                int *worker_cnt_per_group,
6678                                struct r5worker_group **worker_groups)
6679 {
6680         int i, j, k;
6681         ssize_t size;
6682         struct r5worker *workers;
6683
6684         *worker_cnt_per_group = cnt;
6685         if (cnt == 0) {
6686                 *group_cnt = 0;
6687                 *worker_groups = NULL;
6688                 return 0;
6689         }
6690         *group_cnt = num_possible_nodes();
6691         size = sizeof(struct r5worker) * cnt;
6692         workers = kcalloc(size, *group_cnt, GFP_NOIO);
6693         *worker_groups = kcalloc(*group_cnt, sizeof(struct r5worker_group),
6694                                  GFP_NOIO);
6695         if (!*worker_groups || !workers) {
6696                 kfree(workers);
6697                 kfree(*worker_groups);
6698                 return -ENOMEM;
6699         }
6700
6701         for (i = 0; i < *group_cnt; i++) {
6702                 struct r5worker_group *group;
6703
6704                 group = &(*worker_groups)[i];
6705                 INIT_LIST_HEAD(&group->handle_list);
6706                 INIT_LIST_HEAD(&group->loprio_list);
6707                 group->conf = conf;
6708                 group->workers = workers + i * cnt;
6709
6710                 for (j = 0; j < cnt; j++) {
6711                         struct r5worker *worker = group->workers + j;
6712                         worker->group = group;
6713                         INIT_WORK(&worker->work, raid5_do_work);
6714
6715                         for (k = 0; k < NR_STRIPE_HASH_LOCKS; k++)
6716                                 INIT_LIST_HEAD(worker->temp_inactive_list + k);
6717                 }
6718         }
6719
6720         return 0;
6721 }
6722
6723 static void free_thread_groups(struct r5conf *conf)
6724 {
6725         if (conf->worker_groups)
6726                 kfree(conf->worker_groups[0].workers);
6727         kfree(conf->worker_groups);
6728         conf->worker_groups = NULL;
6729 }
6730
6731 static sector_t
6732 raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
6733 {
6734         struct r5conf *conf = mddev->private;
6735
6736         if (!sectors)
6737                 sectors = mddev->dev_sectors;
6738         if (!raid_disks)
6739                 /* size is defined by the smallest of previous and new size */
6740                 raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
6741
6742         sectors &= ~((sector_t)conf->chunk_sectors - 1);
6743         sectors &= ~((sector_t)conf->prev_chunk_sectors - 1);
6744         return sectors * (raid_disks - conf->max_degraded);
6745 }
6746
6747 static void free_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6748 {
6749         safe_put_page(percpu->spare_page);
6750         percpu->spare_page = NULL;
6751         kvfree(percpu->scribble);
6752         percpu->scribble = NULL;
6753 }
6754
6755 static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6756 {
6757         if (conf->level == 6 && !percpu->spare_page) {
6758                 percpu->spare_page = alloc_page(GFP_KERNEL);
6759                 if (!percpu->spare_page)
6760                         return -ENOMEM;
6761         }
6762
6763         if (scribble_alloc(percpu,
6764                            max(conf->raid_disks,
6765                                conf->previous_raid_disks),
6766                            max(conf->chunk_sectors,
6767                                conf->prev_chunk_sectors)
6768                            / STRIPE_SECTORS,
6769                            GFP_KERNEL)) {
6770                 free_scratch_buffer(conf, percpu);
6771                 return -ENOMEM;
6772         }
6773
6774         return 0;
6775 }
6776
6777 static int raid456_cpu_dead(unsigned int cpu, struct hlist_node *node)
6778 {
6779         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
6780
6781         free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));
6782         return 0;
6783 }
6784
6785 static void raid5_free_percpu(struct r5conf *conf)
6786 {
6787         if (!conf->percpu)
6788                 return;
6789
6790         cpuhp_state_remove_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
6791         free_percpu(conf->percpu);
6792 }
6793
6794 static void free_conf(struct r5conf *conf)
6795 {
6796         int i;
6797
6798         log_exit(conf);
6799
6800         unregister_shrinker(&conf->shrinker);
6801         free_thread_groups(conf);
6802         shrink_stripes(conf);
6803         raid5_free_percpu(conf);
6804         for (i = 0; i < conf->pool_size; i++)
6805                 if (conf->disks[i].extra_page)
6806                         put_page(conf->disks[i].extra_page);
6807         kfree(conf->disks);
6808         bioset_exit(&conf->bio_split);
6809         kfree(conf->stripe_hashtbl);
6810         kfree(conf->pending_data);
6811         kfree(conf);
6812 }
6813
6814 static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
6815 {
6816         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
6817         struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);
6818
6819         if (alloc_scratch_buffer(conf, percpu)) {
6820                 pr_warn("%s: failed memory allocation for cpu%u\n",
6821                         __func__, cpu);
6822                 return -ENOMEM;
6823         }
6824         return 0;
6825 }
6826
6827 static int raid5_alloc_percpu(struct r5conf *conf)
6828 {
6829         int err = 0;
6830
6831         conf->percpu = alloc_percpu(struct raid5_percpu);
6832         if (!conf->percpu)
6833                 return -ENOMEM;
6834
6835         err = cpuhp_state_add_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
6836         if (!err) {
6837                 conf->scribble_disks = max(conf->raid_disks,
6838                         conf->previous_raid_disks);
6839                 conf->scribble_sectors = max(conf->chunk_sectors,
6840                         conf->prev_chunk_sectors);
6841         }
6842         return err;
6843 }
6844
6845 static unsigned long raid5_cache_scan(struct shrinker *shrink,
6846                                       struct shrink_control *sc)
6847 {
6848         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6849         unsigned long ret = SHRINK_STOP;
6850
6851         if (mutex_trylock(&conf->cache_size_mutex)) {
6852                 ret= 0;
6853                 while (ret < sc->nr_to_scan &&
6854                        conf->max_nr_stripes > conf->min_nr_stripes) {
6855                         if (drop_one_stripe(conf) == 0) {
6856                                 ret = SHRINK_STOP;
6857                                 break;
6858                         }
6859                         ret++;
6860                 }
6861                 mutex_unlock(&conf->cache_size_mutex);
6862         }
6863         return ret;
6864 }
6865
6866 static unsigned long raid5_cache_count(struct shrinker *shrink,
6867                                        struct shrink_control *sc)
6868 {
6869         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6870
6871         if (conf->max_nr_stripes < conf->min_nr_stripes)
6872                 /* unlikely, but not impossible */
6873                 return 0;
6874         return conf->max_nr_stripes - conf->min_nr_stripes;
6875 }
6876
6877 static struct r5conf *setup_conf(struct mddev *mddev)
6878 {
6879         struct r5conf *conf;
6880         int raid_disk, memory, max_disks;
6881         struct md_rdev *rdev;
6882         struct disk_info *disk;
6883         char pers_name[6];
6884         int i;
6885         int group_cnt, worker_cnt_per_group;
6886         struct r5worker_group *new_group;
6887         int ret;
6888
6889         if (mddev->new_level != 5
6890             && mddev->new_level != 4
6891             && mddev->new_level != 6) {
6892                 pr_warn("md/raid:%s: raid level not set to 4/5/6 (%d)\n",
6893                         mdname(mddev), mddev->new_level);
6894                 return ERR_PTR(-EIO);
6895         }
6896         if ((mddev->new_level == 5
6897              && !algorithm_valid_raid5(mddev->new_layout)) ||
6898             (mddev->new_level == 6
6899              && !algorithm_valid_raid6(mddev->new_layout))) {
6900                 pr_warn("md/raid:%s: layout %d not supported\n",
6901                         mdname(mddev), mddev->new_layout);
6902                 return ERR_PTR(-EIO);
6903         }
6904         if (mddev->new_level == 6 && mddev->raid_disks < 4) {
6905                 pr_warn("md/raid:%s: not enough configured devices (%d, minimum 4)\n",
6906                         mdname(mddev), mddev->raid_disks);
6907                 return ERR_PTR(-EINVAL);
6908         }
6909
6910         if (!mddev->new_chunk_sectors ||
6911             (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
6912             !is_power_of_2(mddev->new_chunk_sectors)) {
6913                 pr_warn("md/raid:%s: invalid chunk size %d\n",
6914                         mdname(mddev), mddev->new_chunk_sectors << 9);
6915                 return ERR_PTR(-EINVAL);
6916         }
6917
6918         conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
6919         if (conf == NULL)
6920                 goto abort;
6921         INIT_LIST_HEAD(&conf->free_list);
6922         INIT_LIST_HEAD(&conf->pending_list);
6923         conf->pending_data = kcalloc(PENDING_IO_MAX,
6924                                      sizeof(struct r5pending_data),
6925                                      GFP_KERNEL);
6926         if (!conf->pending_data)
6927                 goto abort;
6928         for (i = 0; i < PENDING_IO_MAX; i++)
6929                 list_add(&conf->pending_data[i].sibling, &conf->free_list);
6930         /* Don't enable multi-threading by default*/
6931         if (!alloc_thread_groups(conf, 0, &group_cnt, &worker_cnt_per_group,
6932                                  &new_group)) {
6933                 conf->group_cnt = group_cnt;
6934                 conf->worker_cnt_per_group = worker_cnt_per_group;
6935                 conf->worker_groups = new_group;
6936         } else
6937                 goto abort;
6938         spin_lock_init(&conf->device_lock);
6939         seqcount_init(&conf->gen_lock);
6940         mutex_init(&conf->cache_size_mutex);
6941         init_waitqueue_head(&conf->wait_for_quiescent);
6942         init_waitqueue_head(&conf->wait_for_stripe);
6943         init_waitqueue_head(&conf->wait_for_overlap);
6944         INIT_LIST_HEAD(&conf->handle_list);
6945         INIT_LIST_HEAD(&conf->loprio_list);
6946         INIT_LIST_HEAD(&conf->hold_list);
6947         INIT_LIST_HEAD(&conf->delayed_list);
6948         INIT_LIST_HEAD(&conf->bitmap_list);
6949         init_llist_head(&conf->released_stripes);
6950         atomic_set(&conf->active_stripes, 0);
6951         atomic_set(&conf->preread_active_stripes, 0);
6952         atomic_set(&conf->active_aligned_reads, 0);
6953         spin_lock_init(&conf->pending_bios_lock);
6954         conf->batch_bio_dispatch = true;
6955         rdev_for_each(rdev, mddev) {
6956                 if (test_bit(Journal, &rdev->flags))
6957                         continue;
6958                 if (blk_queue_nonrot(bdev_get_queue(rdev->bdev))) {
6959                         conf->batch_bio_dispatch = false;
6960                         break;
6961                 }
6962         }
6963
6964         conf->bypass_threshold = BYPASS_THRESHOLD;
6965         conf->recovery_disabled = mddev->recovery_disabled - 1;
6966
6967         conf->raid_disks = mddev->raid_disks;
6968         if (mddev->reshape_position == MaxSector)
6969                 conf->previous_raid_disks = mddev->raid_disks;
6970         else
6971                 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
6972         max_disks = max(conf->raid_disks, conf->previous_raid_disks);
6973
6974         conf->disks = kcalloc(max_disks, sizeof(struct disk_info),
6975                               GFP_KERNEL);
6976
6977         if (!conf->disks)
6978                 goto abort;
6979
6980         for (i = 0; i < max_disks; i++) {
6981                 conf->disks[i].extra_page = alloc_page(GFP_KERNEL);
6982                 if (!conf->disks[i].extra_page)
6983                         goto abort;
6984         }
6985
6986         ret = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
6987         if (ret)
6988                 goto abort;
6989         conf->mddev = mddev;
6990
6991         if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
6992                 goto abort;
6993
6994         /* We init hash_locks[0] separately to that it can be used
6995          * as the reference lock in the spin_lock_nest_lock() call
6996          * in lock_all_device_hash_locks_irq in order to convince
6997          * lockdep that we know what we are doing.
6998          */
6999         spin_lock_init(conf->hash_locks);
7000         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
7001                 spin_lock_init(conf->hash_locks + i);
7002
7003         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
7004                 INIT_LIST_HEAD(conf->inactive_list + i);
7005
7006         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
7007                 INIT_LIST_HEAD(conf->temp_inactive_list + i);
7008
7009         atomic_set(&conf->r5c_cached_full_stripes, 0);
7010         INIT_LIST_HEAD(&conf->r5c_full_stripe_list);
7011         atomic_set(&conf->r5c_cached_partial_stripes, 0);
7012         INIT_LIST_HEAD(&conf->r5c_partial_stripe_list);
7013         atomic_set(&conf->r5c_flushing_full_stripes, 0);
7014         atomic_set(&conf->r5c_flushing_partial_stripes, 0);
7015
7016         conf->level = mddev->new_level;
7017         conf->chunk_sectors = mddev->new_chunk_sectors;
7018         if (raid5_alloc_percpu(conf) != 0)
7019                 goto abort;
7020
7021         pr_debug("raid456: run(%s) called.\n", mdname(mddev));
7022
7023         rdev_for_each(rdev, mddev) {
7024                 raid_disk = rdev->raid_disk;
7025                 if (raid_disk >= max_disks
7026                     || raid_disk < 0 || test_bit(Journal, &rdev->flags))
7027                         continue;
7028                 disk = conf->disks + raid_disk;
7029
7030                 if (test_bit(Replacement, &rdev->flags)) {
7031                         if (disk->replacement)
7032                                 goto abort;
7033                         disk->replacement = rdev;
7034                 } else {
7035                         if (disk->rdev)
7036                                 goto abort;
7037                         disk->rdev = rdev;
7038                 }
7039
7040                 if (test_bit(In_sync, &rdev->flags)) {
7041                         char b[BDEVNAME_SIZE];
7042                         pr_info("md/raid:%s: device %s operational as raid disk %d\n",
7043                                 mdname(mddev), bdevname(rdev->bdev, b), raid_disk);
7044                 } else if (rdev->saved_raid_disk != raid_disk)
7045                         /* Cannot rely on bitmap to complete recovery */
7046                         conf->fullsync = 1;
7047         }
7048
7049         conf->level = mddev->new_level;
7050         if (conf->level == 6) {
7051                 conf->max_degraded = 2;
7052                 if (raid6_call.xor_syndrome)
7053                         conf->rmw_level = PARITY_ENABLE_RMW;
7054                 else
7055                         conf->rmw_level = PARITY_DISABLE_RMW;
7056         } else {
7057                 conf->max_degraded = 1;
7058                 conf->rmw_level = PARITY_ENABLE_RMW;
7059         }
7060         conf->algorithm = mddev->new_layout;
7061         conf->reshape_progress = mddev->reshape_position;
7062         if (conf->reshape_progress != MaxSector) {
7063                 conf->prev_chunk_sectors = mddev->chunk_sectors;
7064                 conf->prev_algo = mddev->layout;
7065         } else {
7066                 conf->prev_chunk_sectors = conf->chunk_sectors;
7067                 conf->prev_algo = conf->algorithm;
7068         }
7069
7070         conf->min_nr_stripes = NR_STRIPES;
7071         if (mddev->reshape_position != MaxSector) {
7072                 int stripes = max_t(int,
7073                         ((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4,
7074                         ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4);
7075                 conf->min_nr_stripes = max(NR_STRIPES, stripes);
7076                 if (conf->min_nr_stripes != NR_STRIPES)
7077                         pr_info("md/raid:%s: force stripe size %d for reshape\n",
7078                                 mdname(mddev), conf->min_nr_stripes);
7079         }
7080         memory = conf->min_nr_stripes * (sizeof(struct stripe_head) +
7081                  max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
7082         atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS);
7083         if (grow_stripes(conf, conf->min_nr_stripes)) {
7084                 pr_warn("md/raid:%s: couldn't allocate %dkB for buffers\n",
7085                         mdname(mddev), memory);
7086                 goto abort;
7087         } else
7088                 pr_debug("md/raid:%s: allocated %dkB\n", mdname(mddev), memory);
7089         /*
7090          * Losing a stripe head costs more than the time to refill it,
7091          * it reduces the queue depth and so can hurt throughput.
7092          * So set it rather large, scaled by number of devices.
7093          */
7094         conf->shrinker.seeks = DEFAULT_SEEKS * conf->raid_disks * 4;
7095         conf->shrinker.scan_objects = raid5_cache_scan;
7096         conf->shrinker.count_objects = raid5_cache_count;
7097         conf->shrinker.batch = 128;
7098         conf->shrinker.flags = 0;
7099         if (register_shrinker(&conf->shrinker)) {
7100                 pr_warn("md/raid:%s: couldn't register shrinker.\n",
7101                         mdname(mddev));
7102                 goto abort;
7103         }
7104
7105         sprintf(pers_name, "raid%d", mddev->new_level);
7106         conf->thread = md_register_thread(raid5d, mddev, pers_name);
7107         if (!conf->thread) {
7108                 pr_warn("md/raid:%s: couldn't allocate thread.\n",
7109                         mdname(mddev));
7110                 goto abort;
7111         }
7112
7113         return conf;
7114
7115  abort:
7116         if (conf) {
7117                 free_conf(conf);
7118                 return ERR_PTR(-EIO);
7119         } else
7120                 return ERR_PTR(-ENOMEM);
7121 }
7122
7123 static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
7124 {
7125         switch (algo) {
7126         case ALGORITHM_PARITY_0:
7127                 if (raid_disk < max_degraded)
7128                         return 1;
7129                 break;
7130         case ALGORITHM_PARITY_N:
7131                 if (raid_disk >= raid_disks - max_degraded)
7132                         return 1;
7133                 break;
7134         case ALGORITHM_PARITY_0_6:
7135                 if (raid_disk == 0 ||
7136                     raid_disk == raid_disks - 1)
7137                         return 1;
7138                 break;
7139         case ALGORITHM_LEFT_ASYMMETRIC_6:
7140         case ALGORITHM_RIGHT_ASYMMETRIC_6:
7141         case ALGORITHM_LEFT_SYMMETRIC_6:
7142         case ALGORITHM_RIGHT_SYMMETRIC_6:
7143                 if (raid_disk == raid_disks - 1)
7144                         return 1;
7145         }
7146         return 0;
7147 }
7148
7149 static int raid5_run(struct mddev *mddev)
7150 {
7151         struct r5conf *conf;
7152         int working_disks = 0;
7153         int dirty_parity_disks = 0;
7154         struct md_rdev *rdev;
7155         struct md_rdev *journal_dev = NULL;
7156         sector_t reshape_offset = 0;
7157         int i;
7158         long long min_offset_diff = 0;
7159         int first = 1;
7160
7161         if (mddev_init_writes_pending(mddev) < 0)
7162                 return -ENOMEM;
7163
7164         if (mddev->recovery_cp != MaxSector)
7165                 pr_notice("md/raid:%s: not clean -- starting background reconstruction\n",
7166                           mdname(mddev));
7167
7168         rdev_for_each(rdev, mddev) {
7169                 long long diff;
7170
7171                 if (test_bit(Journal, &rdev->flags)) {
7172                         journal_dev = rdev;
7173                         continue;
7174                 }
7175                 if (rdev->raid_disk < 0)
7176                         continue;
7177                 diff = (rdev->new_data_offset - rdev->data_offset);
7178                 if (first) {
7179                         min_offset_diff = diff;
7180                         first = 0;
7181                 } else if (mddev->reshape_backwards &&
7182                          diff < min_offset_diff)
7183                         min_offset_diff = diff;
7184                 else if (!mddev->reshape_backwards &&
7185                          diff > min_offset_diff)
7186                         min_offset_diff = diff;
7187         }
7188
7189         if ((test_bit(MD_HAS_JOURNAL, &mddev->flags) || journal_dev) &&
7190             (mddev->bitmap_info.offset || mddev->bitmap_info.file)) {
7191                 pr_notice("md/raid:%s: array cannot have both journal and bitmap\n",
7192                           mdname(mddev));
7193                 return -EINVAL;
7194         }
7195
7196         if (mddev->reshape_position != MaxSector) {
7197                 /* Check that we can continue the reshape.
7198                  * Difficulties arise if the stripe we would write to
7199                  * next is at or after the stripe we would read from next.
7200                  * For a reshape that changes the number of devices, this
7201                  * is only possible for a very short time, and mdadm makes
7202                  * sure that time appears to have past before assembling
7203                  * the array.  So we fail if that time hasn't passed.
7204                  * For a reshape that keeps the number of devices the same
7205                  * mdadm must be monitoring the reshape can keeping the
7206                  * critical areas read-only and backed up.  It will start
7207                  * the array in read-only mode, so we check for that.
7208                  */
7209                 sector_t here_new, here_old;
7210                 int old_disks;
7211                 int max_degraded = (mddev->level == 6 ? 2 : 1);
7212                 int chunk_sectors;
7213                 int new_data_disks;
7214
7215                 if (journal_dev) {
7216                         pr_warn("md/raid:%s: don't support reshape with journal - aborting.\n",
7217                                 mdname(mddev));
7218                         return -EINVAL;
7219                 }
7220
7221                 if (mddev->new_level != mddev->level) {
7222                         pr_warn("md/raid:%s: unsupported reshape required - aborting.\n",
7223                                 mdname(mddev));
7224                         return -EINVAL;
7225                 }
7226                 old_disks = mddev->raid_disks - mddev->delta_disks;
7227                 /* reshape_position must be on a new-stripe boundary, and one
7228                  * further up in new geometry must map after here in old
7229                  * geometry.
7230                  * If the chunk sizes are different, then as we perform reshape
7231                  * in units of the largest of the two, reshape_position needs
7232                  * be a multiple of the largest chunk size times new data disks.
7233                  */
7234                 here_new = mddev->reshape_position;
7235                 chunk_sectors = max(mddev->chunk_sectors, mddev->new_chunk_sectors);
7236                 new_data_disks = mddev->raid_disks - max_degraded;
7237                 if (sector_div(here_new, chunk_sectors * new_data_disks)) {
7238                         pr_warn("md/raid:%s: reshape_position not on a stripe boundary\n",
7239                                 mdname(mddev));
7240                         return -EINVAL;
7241                 }
7242                 reshape_offset = here_new * chunk_sectors;
7243                 /* here_new is the stripe we will write to */
7244                 here_old = mddev->reshape_position;
7245                 sector_div(here_old, chunk_sectors * (old_disks-max_degraded));
7246                 /* here_old is the first stripe that we might need to read
7247                  * from */
7248                 if (mddev->delta_disks == 0) {
7249                         /* We cannot be sure it is safe to start an in-place
7250                          * reshape.  It is only safe if user-space is monitoring
7251                          * and taking constant backups.
7252                          * mdadm always starts a situation like this in
7253                          * readonly mode so it can take control before
7254                          * allowing any writes.  So just check for that.
7255                          */
7256                         if (abs(min_offset_diff) >= mddev->chunk_sectors &&
7257                             abs(min_offset_diff) >= mddev->new_chunk_sectors)
7258                                 /* not really in-place - so OK */;
7259                         else if (mddev->ro == 0) {
7260                                 pr_warn("md/raid:%s: in-place reshape must be started in read-only mode - aborting\n",
7261                                         mdname(mddev));
7262                                 return -EINVAL;
7263                         }
7264                 } else if (mddev->reshape_backwards
7265                     ? (here_new * chunk_sectors + min_offset_diff <=
7266                        here_old * chunk_sectors)
7267                     : (here_new * chunk_sectors >=
7268                        here_old * chunk_sectors + (-min_offset_diff))) {
7269                         /* Reading from the same stripe as writing to - bad */
7270                         pr_warn("md/raid:%s: reshape_position too early for auto-recovery - aborting.\n",
7271                                 mdname(mddev));
7272                         return -EINVAL;
7273                 }
7274                 pr_debug("md/raid:%s: reshape will continue\n", mdname(mddev));
7275                 /* OK, we should be able to continue; */
7276         } else {
7277                 BUG_ON(mddev->level != mddev->new_level);
7278                 BUG_ON(mddev->layout != mddev->new_layout);
7279                 BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
7280                 BUG_ON(mddev->delta_disks != 0);
7281         }
7282
7283         if (test_bit(MD_HAS_JOURNAL, &mddev->flags) &&
7284             test_bit(MD_HAS_PPL, &mddev->flags)) {
7285                 pr_warn("md/raid:%s: using journal device and PPL not allowed - disabling PPL\n",
7286                         mdname(mddev));
7287                 clear_bit(MD_HAS_PPL, &mddev->flags);
7288                 clear_bit(MD_HAS_MULTIPLE_PPLS, &mddev->flags);
7289         }
7290
7291         if (mddev->private == NULL)
7292                 conf = setup_conf(mddev);
7293         else
7294                 conf = mddev->private;
7295
7296         if (IS_ERR(conf))
7297                 return PTR_ERR(conf);
7298
7299         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
7300                 if (!journal_dev) {
7301                         pr_warn("md/raid:%s: journal disk is missing, force array readonly\n",
7302                                 mdname(mddev));
7303                         mddev->ro = 1;
7304                         set_disk_ro(mddev->gendisk, 1);
7305                 } else if (mddev->recovery_cp == MaxSector)
7306                         set_bit(MD_JOURNAL_CLEAN, &mddev->flags);
7307         }
7308
7309         conf->min_offset_diff = min_offset_diff;
7310         mddev->thread = conf->thread;
7311         conf->thread = NULL;
7312         mddev->private = conf;
7313
7314         for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
7315              i++) {
7316                 rdev = conf->disks[i].rdev;
7317                 if (!rdev && conf->disks[i].replacement) {
7318                         /* The replacement is all we have yet */
7319                         rdev = conf->disks[i].replacement;
7320                         conf->disks[i].replacement = NULL;
7321                         clear_bit(Replacement, &rdev->flags);
7322                         conf->disks[i].rdev = rdev;
7323                 }
7324                 if (!rdev)
7325                         continue;
7326                 if (conf->disks[i].replacement &&
7327                     conf->reshape_progress != MaxSector) {
7328                         /* replacements and reshape simply do not mix. */
7329                         pr_warn("md: cannot handle concurrent replacement and reshape.\n");
7330                         goto abort;
7331                 }
7332                 if (test_bit(In_sync, &rdev->flags)) {
7333                         working_disks++;
7334                         continue;
7335                 }
7336                 /* This disc is not fully in-sync.  However if it
7337                  * just stored parity (beyond the recovery_offset),
7338                  * when we don't need to be concerned about the
7339                  * array being dirty.
7340                  * When reshape goes 'backwards', we never have
7341                  * partially completed devices, so we only need
7342                  * to worry about reshape going forwards.
7343                  */
7344                 /* Hack because v0.91 doesn't store recovery_offset properly. */
7345                 if (mddev->major_version == 0 &&
7346                     mddev->minor_version > 90)
7347                         rdev->recovery_offset = reshape_offset;
7348
7349                 if (rdev->recovery_offset < reshape_offset) {
7350                         /* We need to check old and new layout */
7351                         if (!only_parity(rdev->raid_disk,
7352                                          conf->algorithm,
7353                                          conf->raid_disks,
7354                                          conf->max_degraded))
7355                                 continue;
7356                 }
7357                 if (!only_parity(rdev->raid_disk,
7358                                  conf->prev_algo,
7359                                  conf->previous_raid_disks,
7360                                  conf->max_degraded))
7361                         continue;
7362                 dirty_parity_disks++;
7363         }
7364
7365         /*
7366          * 0 for a fully functional array, 1 or 2 for a degraded array.
7367          */
7368         mddev->degraded = raid5_calc_degraded(conf);
7369
7370         if (has_failed(conf)) {
7371                 pr_crit("md/raid:%s: not enough operational devices (%d/%d failed)\n",
7372                         mdname(mddev), mddev->degraded, conf->raid_disks);
7373                 goto abort;
7374         }
7375
7376         /* device size must be a multiple of chunk size */
7377         mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
7378         mddev->resync_max_sectors = mddev->dev_sectors;
7379
7380         if (mddev->degraded > dirty_parity_disks &&
7381             mddev->recovery_cp != MaxSector) {
7382                 if (test_bit(MD_HAS_PPL, &mddev->flags))
7383                         pr_crit("md/raid:%s: starting dirty degraded array with PPL.\n",
7384                                 mdname(mddev));
7385                 else if (mddev->ok_start_degraded)
7386                         pr_crit("md/raid:%s: starting dirty degraded array - data corruption possible.\n",
7387                                 mdname(mddev));
7388                 else {
7389                         pr_crit("md/raid:%s: cannot start dirty degraded array.\n",
7390                                 mdname(mddev));
7391                         goto abort;
7392                 }
7393         }
7394
7395         pr_info("md/raid:%s: raid level %d active with %d out of %d devices, algorithm %d\n",
7396                 mdname(mddev), conf->level,
7397                 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
7398                 mddev->new_layout);
7399
7400         print_raid5_conf(conf);
7401
7402         if (conf->reshape_progress != MaxSector) {
7403                 conf->reshape_safe = conf->reshape_progress;
7404                 atomic_set(&conf->reshape_stripes, 0);
7405                 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7406                 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7407                 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7408                 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7409                 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7410                                                         "reshape");
7411                 if (!mddev->sync_thread)
7412                         goto abort;
7413         }
7414
7415         /* Ok, everything is just fine now */
7416         if (mddev->to_remove == &raid5_attrs_group)
7417                 mddev->to_remove = NULL;
7418         else if (mddev->kobj.sd &&
7419             sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
7420                 pr_warn("raid5: failed to create sysfs attributes for %s\n",
7421                         mdname(mddev));
7422         md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
7423
7424         if (mddev->queue) {
7425                 int chunk_size;
7426                 /* read-ahead size must cover two whole stripes, which
7427                  * is 2 * (datadisks) * chunksize where 'n' is the
7428                  * number of raid devices
7429                  */
7430                 int data_disks = conf->previous_raid_disks - conf->max_degraded;
7431                 int stripe = data_disks *
7432                         ((mddev->chunk_sectors << 9) / PAGE_SIZE);
7433                 if (mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
7434                         mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
7435
7436                 chunk_size = mddev->chunk_sectors << 9;
7437                 blk_queue_io_min(mddev->queue, chunk_size);
7438                 blk_queue_io_opt(mddev->queue, chunk_size *
7439                                  (conf->raid_disks - conf->max_degraded));
7440                 mddev->queue->limits.raid_partial_stripes_expensive = 1;
7441                 /*
7442                  * We can only discard a whole stripe. It doesn't make sense to
7443                  * discard data disk but write parity disk
7444                  */
7445                 stripe = stripe * PAGE_SIZE;
7446                 /* Round up to power of 2, as discard handling
7447                  * currently assumes that */
7448                 while ((stripe-1) & stripe)
7449                         stripe = (stripe | (stripe-1)) + 1;
7450                 mddev->queue->limits.discard_alignment = stripe;
7451                 mddev->queue->limits.discard_granularity = stripe;
7452
7453                 blk_queue_max_write_same_sectors(mddev->queue, 0);
7454                 blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
7455
7456                 rdev_for_each(rdev, mddev) {
7457                         disk_stack_limits(mddev->gendisk, rdev->bdev,
7458                                           rdev->data_offset << 9);
7459                         disk_stack_limits(mddev->gendisk, rdev->bdev,
7460                                           rdev->new_data_offset << 9);
7461                 }
7462
7463                 /*
7464                  * zeroing is required, otherwise data
7465                  * could be lost. Consider a scenario: discard a stripe
7466                  * (the stripe could be inconsistent if
7467                  * discard_zeroes_data is 0); write one disk of the
7468                  * stripe (the stripe could be inconsistent again
7469                  * depending on which disks are used to calculate
7470                  * parity); the disk is broken; The stripe data of this
7471                  * disk is lost.
7472                  *
7473                  * We only allow DISCARD if the sysadmin has confirmed that
7474                  * only safe devices are in use by setting a module parameter.
7475                  * A better idea might be to turn DISCARD into WRITE_ZEROES
7476                  * requests, as that is required to be safe.
7477                  */
7478                 if (devices_handle_discard_safely &&
7479                     mddev->queue->limits.max_discard_sectors >= (stripe >> 9) &&
7480                     mddev->queue->limits.discard_granularity >= stripe)
7481                         blk_queue_flag_set(QUEUE_FLAG_DISCARD,
7482                                                 mddev->queue);
7483                 else
7484                         blk_queue_flag_clear(QUEUE_FLAG_DISCARD,
7485                                                 mddev->queue);
7486
7487                 blk_queue_max_hw_sectors(mddev->queue, UINT_MAX);
7488         }
7489
7490         if (log_init(conf, journal_dev, raid5_has_ppl(conf)))
7491                 goto abort;
7492
7493         return 0;
7494 abort:
7495         md_unregister_thread(&mddev->thread);
7496         print_raid5_conf(conf);
7497         free_conf(conf);
7498         mddev->private = NULL;
7499         pr_warn("md/raid:%s: failed to run raid set.\n", mdname(mddev));
7500         return -EIO;
7501 }
7502
7503 static void raid5_free(struct mddev *mddev, void *priv)
7504 {
7505         struct r5conf *conf = priv;
7506
7507         free_conf(conf);
7508         mddev->to_remove = &raid5_attrs_group;
7509 }
7510
7511 static void raid5_status(struct seq_file *seq, struct mddev *mddev)
7512 {
7513         struct r5conf *conf = mddev->private;
7514         int i;
7515
7516         seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
7517                 conf->chunk_sectors / 2, mddev->layout);
7518         seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
7519         rcu_read_lock();
7520         for (i = 0; i < conf->raid_disks; i++) {
7521                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
7522                 seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
7523         }
7524         rcu_read_unlock();
7525         seq_printf (seq, "]");
7526 }
7527
7528 static void print_raid5_conf (struct r5conf *conf)
7529 {
7530         int i;
7531         struct disk_info *tmp;
7532
7533         pr_debug("RAID conf printout:\n");
7534         if (!conf) {
7535                 pr_debug("(conf==NULL)\n");
7536                 return;
7537         }
7538         pr_debug(" --- level:%d rd:%d wd:%d\n", conf->level,
7539                conf->raid_disks,
7540                conf->raid_disks - conf->mddev->degraded);
7541
7542         for (i = 0; i < conf->raid_disks; i++) {
7543                 char b[BDEVNAME_SIZE];
7544                 tmp = conf->disks + i;
7545                 if (tmp->rdev)
7546                         pr_debug(" disk %d, o:%d, dev:%s\n",
7547                                i, !test_bit(Faulty, &tmp->rdev->flags),
7548                                bdevname(tmp->rdev->bdev, b));
7549         }
7550 }
7551
7552 static int raid5_spare_active(struct mddev *mddev)
7553 {
7554         int i;
7555         struct r5conf *conf = mddev->private;
7556         struct disk_info *tmp;
7557         int count = 0;
7558         unsigned long flags;
7559
7560         for (i = 0; i < conf->raid_disks; i++) {
7561                 tmp = conf->disks + i;
7562                 if (tmp->replacement
7563                     && tmp->replacement->recovery_offset == MaxSector
7564                     && !test_bit(Faulty, &tmp->replacement->flags)
7565                     && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
7566                         /* Replacement has just become active. */
7567                         if (!tmp->rdev
7568                             || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
7569                                 count++;
7570                         if (tmp->rdev) {
7571                                 /* Replaced device not technically faulty,
7572                                  * but we need to be sure it gets removed
7573                                  * and never re-added.
7574                                  */
7575                                 set_bit(Faulty, &tmp->rdev->flags);
7576                                 sysfs_notify_dirent_safe(
7577                                         tmp->rdev->sysfs_state);
7578                         }
7579                         sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
7580                 } else if (tmp->rdev
7581                     && tmp->rdev->recovery_offset == MaxSector
7582                     && !test_bit(Faulty, &tmp->rdev->flags)
7583                     && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
7584                         count++;
7585                         sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
7586                 }
7587         }
7588         spin_lock_irqsave(&conf->device_lock, flags);
7589         mddev->degraded = raid5_calc_degraded(conf);
7590         spin_unlock_irqrestore(&conf->device_lock, flags);
7591         print_raid5_conf(conf);
7592         return count;
7593 }
7594
7595 static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
7596 {
7597         struct r5conf *conf = mddev->private;
7598         int err = 0;
7599         int number = rdev->raid_disk;
7600         struct md_rdev **rdevp;
7601         struct disk_info *p = conf->disks + number;
7602
7603         print_raid5_conf(conf);
7604         if (test_bit(Journal, &rdev->flags) && conf->log) {
7605                 /*
7606                  * we can't wait pending write here, as this is called in
7607                  * raid5d, wait will deadlock.
7608                  * neilb: there is no locking about new writes here,
7609                  * so this cannot be safe.
7610                  */
7611                 if (atomic_read(&conf->active_stripes) ||
7612                     atomic_read(&conf->r5c_cached_full_stripes) ||
7613                     atomic_read(&conf->r5c_cached_partial_stripes)) {
7614                         return -EBUSY;
7615                 }
7616                 log_exit(conf);
7617                 return 0;
7618         }
7619         if (rdev == p->rdev)
7620                 rdevp = &p->rdev;
7621         else if (rdev == p->replacement)
7622                 rdevp = &p->replacement;
7623         else
7624                 return 0;
7625
7626         if (number >= conf->raid_disks &&
7627             conf->reshape_progress == MaxSector)
7628                 clear_bit(In_sync, &rdev->flags);
7629
7630         if (test_bit(In_sync, &rdev->flags) ||
7631             atomic_read(&rdev->nr_pending)) {
7632                 err = -EBUSY;
7633                 goto abort;
7634         }
7635         /* Only remove non-faulty devices if recovery
7636          * isn't possible.
7637          */
7638         if (!test_bit(Faulty, &rdev->flags) &&
7639             mddev->recovery_disabled != conf->recovery_disabled &&
7640             !has_failed(conf) &&
7641             (!p->replacement || p->replacement == rdev) &&
7642             number < conf->raid_disks) {
7643                 err = -EBUSY;
7644                 goto abort;
7645         }
7646         *rdevp = NULL;
7647         if (!test_bit(RemoveSynchronized, &rdev->flags)) {
7648                 synchronize_rcu();
7649                 if (atomic_read(&rdev->nr_pending)) {
7650                         /* lost the race, try later */
7651                         err = -EBUSY;
7652                         *rdevp = rdev;
7653                 }
7654         }
7655         if (!err) {
7656                 err = log_modify(conf, rdev, false);
7657                 if (err)
7658                         goto abort;
7659         }
7660         if (p->replacement) {
7661                 /* We must have just cleared 'rdev' */
7662                 p->rdev = p->replacement;
7663                 clear_bit(Replacement, &p->replacement->flags);
7664                 smp_mb(); /* Make sure other CPUs may see both as identical
7665                            * but will never see neither - if they are careful
7666                            */
7667                 p->replacement = NULL;
7668
7669                 if (!err)
7670                         err = log_modify(conf, p->rdev, true);
7671         }
7672
7673         clear_bit(WantReplacement, &rdev->flags);
7674 abort:
7675
7676         print_raid5_conf(conf);
7677         return err;
7678 }
7679
7680 static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
7681 {
7682         struct r5conf *conf = mddev->private;
7683         int ret, err = -EEXIST;
7684         int disk;
7685         struct disk_info *p;
7686         int first = 0;
7687         int last = conf->raid_disks - 1;
7688
7689         if (test_bit(Journal, &rdev->flags)) {
7690                 if (conf->log)
7691                         return -EBUSY;
7692
7693                 rdev->raid_disk = 0;
7694                 /*
7695                  * The array is in readonly mode if journal is missing, so no
7696                  * write requests running. We should be safe
7697                  */
7698                 ret = log_init(conf, rdev, false);
7699                 if (ret)
7700                         return ret;
7701
7702                 ret = r5l_start(conf->log);
7703                 if (ret)
7704                         return ret;
7705
7706                 return 0;
7707         }
7708         if (mddev->recovery_disabled == conf->recovery_disabled)
7709                 return -EBUSY;
7710
7711         if (rdev->saved_raid_disk < 0 && has_failed(conf))
7712                 /* no point adding a device */
7713                 return -EINVAL;
7714
7715         if (rdev->raid_disk >= 0)
7716                 first = last = rdev->raid_disk;
7717
7718         /*
7719          * find the disk ... but prefer rdev->saved_raid_disk
7720          * if possible.
7721          */
7722         if (rdev->saved_raid_disk >= 0 &&
7723             rdev->saved_raid_disk >= first &&
7724             conf->disks[rdev->saved_raid_disk].rdev == NULL)
7725                 first = rdev->saved_raid_disk;
7726
7727         for (disk = first; disk <= last; disk++) {
7728                 p = conf->disks + disk;
7729                 if (p->rdev == NULL) {
7730                         clear_bit(In_sync, &rdev->flags);
7731                         rdev->raid_disk = disk;
7732                         if (rdev->saved_raid_disk != disk)
7733                                 conf->fullsync = 1;
7734                         rcu_assign_pointer(p->rdev, rdev);
7735
7736                         err = log_modify(conf, rdev, true);
7737
7738                         goto out;
7739                 }
7740         }
7741         for (disk = first; disk <= last; disk++) {
7742                 p = conf->disks + disk;
7743                 if (test_bit(WantReplacement, &p->rdev->flags) &&
7744                     p->replacement == NULL) {
7745                         clear_bit(In_sync, &rdev->flags);
7746                         set_bit(Replacement, &rdev->flags);
7747                         rdev->raid_disk = disk;
7748                         err = 0;
7749                         conf->fullsync = 1;
7750                         rcu_assign_pointer(p->replacement, rdev);
7751                         break;
7752                 }
7753         }
7754 out:
7755         print_raid5_conf(conf);
7756         return err;
7757 }
7758
7759 static int raid5_resize(struct mddev *mddev, sector_t sectors)
7760 {
7761         /* no resync is happening, and there is enough space
7762          * on all devices, so we can resize.
7763          * We need to make sure resync covers any new space.
7764          * If the array is shrinking we should possibly wait until
7765          * any io in the removed space completes, but it hardly seems
7766          * worth it.
7767          */
7768         sector_t newsize;
7769         struct r5conf *conf = mddev->private;
7770
7771         if (raid5_has_log(conf) || raid5_has_ppl(conf))
7772                 return -EINVAL;
7773         sectors &= ~((sector_t)conf->chunk_sectors - 1);
7774         newsize = raid5_size(mddev, sectors, mddev->raid_disks);
7775         if (mddev->external_size &&
7776             mddev->array_sectors > newsize)
7777                 return -EINVAL;
7778         if (mddev->bitmap) {
7779                 int ret = md_bitmap_resize(mddev->bitmap, sectors, 0, 0);
7780                 if (ret)
7781                         return ret;
7782         }
7783         md_set_array_sectors(mddev, newsize);
7784         if (sectors > mddev->dev_sectors &&
7785             mddev->recovery_cp > mddev->dev_sectors) {
7786                 mddev->recovery_cp = mddev->dev_sectors;
7787                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7788         }
7789         mddev->dev_sectors = sectors;
7790         mddev->resync_max_sectors = sectors;
7791         return 0;
7792 }
7793
7794 static int check_stripe_cache(struct mddev *mddev)
7795 {
7796         /* Can only proceed if there are plenty of stripe_heads.
7797          * We need a minimum of one full stripe,, and for sensible progress
7798          * it is best to have about 4 times that.
7799          * If we require 4 times, then the default 256 4K stripe_heads will
7800          * allow for chunk sizes up to 256K, which is probably OK.
7801          * If the chunk size is greater, user-space should request more
7802          * stripe_heads first.
7803          */
7804         struct r5conf *conf = mddev->private;
7805         if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4
7806             > conf->min_nr_stripes ||
7807             ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4
7808             > conf->min_nr_stripes) {
7809                 pr_warn("md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
7810                         mdname(mddev),
7811                         ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
7812                          / STRIPE_SIZE)*4);
7813                 return 0;
7814         }
7815         return 1;
7816 }
7817
7818 static int check_reshape(struct mddev *mddev)
7819 {
7820         struct r5conf *conf = mddev->private;
7821
7822         if (raid5_has_log(conf) || raid5_has_ppl(conf))
7823                 return -EINVAL;
7824         if (mddev->delta_disks == 0 &&
7825             mddev->new_layout == mddev->layout &&
7826             mddev->new_chunk_sectors == mddev->chunk_sectors)
7827                 return 0; /* nothing to do */
7828         if (has_failed(conf))
7829                 return -EINVAL;
7830         if (mddev->delta_disks < 0 && mddev->reshape_position == MaxSector) {
7831                 /* We might be able to shrink, but the devices must
7832                  * be made bigger first.
7833                  * For raid6, 4 is the minimum size.
7834                  * Otherwise 2 is the minimum
7835                  */
7836                 int min = 2;
7837                 if (mddev->level == 6)
7838                         min = 4;
7839                 if (mddev->raid_disks + mddev->delta_disks < min)
7840                         return -EINVAL;
7841         }
7842
7843         if (!check_stripe_cache(mddev))
7844                 return -ENOSPC;
7845
7846         if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
7847             mddev->delta_disks > 0)
7848                 if (resize_chunks(conf,
7849                                   conf->previous_raid_disks
7850                                   + max(0, mddev->delta_disks),
7851                                   max(mddev->new_chunk_sectors,
7852                                       mddev->chunk_sectors)
7853                             ) < 0)
7854                         return -ENOMEM;
7855
7856         if (conf->previous_raid_disks + mddev->delta_disks <= conf->pool_size)
7857                 return 0; /* never bother to shrink */
7858         return resize_stripes(conf, (conf->previous_raid_disks
7859                                      + mddev->delta_disks));
7860 }
7861
7862 static int raid5_start_reshape(struct mddev *mddev)
7863 {
7864         struct r5conf *conf = mddev->private;
7865         struct md_rdev *rdev;
7866         int spares = 0;
7867         unsigned long flags;
7868
7869         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
7870                 return -EBUSY;
7871
7872         if (!check_stripe_cache(mddev))
7873                 return -ENOSPC;
7874
7875         if (has_failed(conf))
7876                 return -EINVAL;
7877
7878         rdev_for_each(rdev, mddev) {
7879                 if (!test_bit(In_sync, &rdev->flags)
7880                     && !test_bit(Faulty, &rdev->flags))
7881                         spares++;
7882         }
7883
7884         if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
7885                 /* Not enough devices even to make a degraded array
7886                  * of that size
7887                  */
7888                 return -EINVAL;
7889
7890         /* Refuse to reduce size of the array.  Any reductions in
7891          * array size must be through explicit setting of array_size
7892          * attribute.
7893          */
7894         if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
7895             < mddev->array_sectors) {
7896                 pr_warn("md/raid:%s: array size must be reduced before number of disks\n",
7897                         mdname(mddev));
7898                 return -EINVAL;
7899         }
7900
7901         atomic_set(&conf->reshape_stripes, 0);
7902         spin_lock_irq(&conf->device_lock);
7903         write_seqcount_begin(&conf->gen_lock);
7904         conf->previous_raid_disks = conf->raid_disks;
7905         conf->raid_disks += mddev->delta_disks;
7906         conf->prev_chunk_sectors = conf->chunk_sectors;
7907         conf->chunk_sectors = mddev->new_chunk_sectors;
7908         conf->prev_algo = conf->algorithm;
7909         conf->algorithm = mddev->new_layout;
7910         conf->generation++;
7911         /* Code that selects data_offset needs to see the generation update
7912          * if reshape_progress has been set - so a memory barrier needed.
7913          */
7914         smp_mb();
7915         if (mddev->reshape_backwards)
7916                 conf->reshape_progress = raid5_size(mddev, 0, 0);
7917         else
7918                 conf->reshape_progress = 0;
7919         conf->reshape_safe = conf->reshape_progress;
7920         write_seqcount_end(&conf->gen_lock);
7921         spin_unlock_irq(&conf->device_lock);
7922
7923         /* Now make sure any requests that proceeded on the assumption
7924          * the reshape wasn't running - like Discard or Read - have
7925          * completed.
7926          */
7927         mddev_suspend(mddev);
7928         mddev_resume(mddev);
7929
7930         /* Add some new drives, as many as will fit.
7931          * We know there are enough to make the newly sized array work.
7932          * Don't add devices if we are reducing the number of
7933          * devices in the array.  This is because it is not possible
7934          * to correctly record the "partially reconstructed" state of
7935          * such devices during the reshape and confusion could result.
7936          */
7937         if (mddev->delta_disks >= 0) {
7938                 rdev_for_each(rdev, mddev)
7939                         if (rdev->raid_disk < 0 &&
7940                             !test_bit(Faulty, &rdev->flags)) {
7941                                 if (raid5_add_disk(mddev, rdev) == 0) {
7942                                         if (rdev->raid_disk
7943                                             >= conf->previous_raid_disks)
7944                                                 set_bit(In_sync, &rdev->flags);
7945                                         else
7946                                                 rdev->recovery_offset = 0;
7947
7948                                         if (sysfs_link_rdev(mddev, rdev))
7949                                                 /* Failure here is OK */;
7950                                 }
7951                         } else if (rdev->raid_disk >= conf->previous_raid_disks
7952                                    && !test_bit(Faulty, &rdev->flags)) {
7953                                 /* This is a spare that was manually added */
7954                                 set_bit(In_sync, &rdev->flags);
7955                         }
7956
7957                 /* When a reshape changes the number of devices,
7958                  * ->degraded is measured against the larger of the
7959                  * pre and post number of devices.
7960                  */
7961                 spin_lock_irqsave(&conf->device_lock, flags);
7962                 mddev->degraded = raid5_calc_degraded(conf);
7963                 spin_unlock_irqrestore(&conf->device_lock, flags);
7964         }
7965         mddev->raid_disks = conf->raid_disks;
7966         mddev->reshape_position = conf->reshape_progress;
7967         set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
7968
7969         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7970         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7971         clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
7972         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7973         set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7974         mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7975                                                 "reshape");
7976         if (!mddev->sync_thread) {
7977                 mddev->recovery = 0;
7978                 spin_lock_irq(&conf->device_lock);
7979                 write_seqcount_begin(&conf->gen_lock);
7980                 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
7981                 mddev->new_chunk_sectors =
7982                         conf->chunk_sectors = conf->prev_chunk_sectors;
7983                 mddev->new_layout = conf->algorithm = conf->prev_algo;
7984                 rdev_for_each(rdev, mddev)
7985                         rdev->new_data_offset = rdev->data_offset;
7986                 smp_wmb();
7987                 conf->generation --;
7988                 conf->reshape_progress = MaxSector;
7989                 mddev->reshape_position = MaxSector;
7990                 write_seqcount_end(&conf->gen_lock);
7991                 spin_unlock_irq(&conf->device_lock);
7992                 return -EAGAIN;
7993         }
7994         conf->reshape_checkpoint = jiffies;
7995         md_wakeup_thread(mddev->sync_thread);
7996         md_new_event(mddev);
7997         return 0;
7998 }
7999
8000 /* This is called from the reshape thread and should make any
8001  * changes needed in 'conf'
8002  */
8003 static void end_reshape(struct r5conf *conf)
8004 {
8005
8006         if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
8007                 struct md_rdev *rdev;
8008
8009                 spin_lock_irq(&conf->device_lock);
8010                 conf->previous_raid_disks = conf->raid_disks;
8011                 md_finish_reshape(conf->mddev);
8012                 smp_wmb();
8013                 conf->reshape_progress = MaxSector;
8014                 conf->mddev->reshape_position = MaxSector;
8015                 rdev_for_each(rdev, conf->mddev)
8016                         if (rdev->raid_disk >= 0 &&
8017                             !test_bit(Journal, &rdev->flags) &&
8018                             !test_bit(In_sync, &rdev->flags))
8019                                 rdev->recovery_offset = MaxSector;
8020                 spin_unlock_irq(&conf->device_lock);
8021                 wake_up(&conf->wait_for_overlap);
8022
8023                 /* read-ahead size must cover two whole stripes, which is
8024                  * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
8025                  */
8026                 if (conf->mddev->queue) {
8027                         int data_disks = conf->raid_disks - conf->max_degraded;
8028                         int stripe = data_disks * ((conf->chunk_sectors << 9)
8029                                                    / PAGE_SIZE);
8030                         if (conf->mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
8031                                 conf->mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
8032                 }
8033         }
8034 }
8035
8036 /* This is called from the raid5d thread with mddev_lock held.
8037  * It makes config changes to the device.
8038  */
8039 static void raid5_finish_reshape(struct mddev *mddev)
8040 {
8041         struct r5conf *conf = mddev->private;
8042
8043         if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
8044
8045                 if (mddev->delta_disks <= 0) {
8046                         int d;
8047                         spin_lock_irq(&conf->device_lock);
8048                         mddev->degraded = raid5_calc_degraded(conf);
8049                         spin_unlock_irq(&conf->device_lock);
8050                         for (d = conf->raid_disks ;
8051                              d < conf->raid_disks - mddev->delta_disks;
8052                              d++) {
8053                                 struct md_rdev *rdev = conf->disks[d].rdev;
8054                                 if (rdev)
8055                                         clear_bit(In_sync, &rdev->flags);
8056                                 rdev = conf->disks[d].replacement;
8057                                 if (rdev)
8058                                         clear_bit(In_sync, &rdev->flags);
8059                         }
8060                 }
8061                 mddev->layout = conf->algorithm;
8062                 mddev->chunk_sectors = conf->chunk_sectors;
8063                 mddev->reshape_position = MaxSector;
8064                 mddev->delta_disks = 0;
8065                 mddev->reshape_backwards = 0;
8066         }
8067 }
8068
8069 static void raid5_quiesce(struct mddev *mddev, int quiesce)
8070 {
8071         struct r5conf *conf = mddev->private;
8072
8073         if (quiesce) {
8074                 /* stop all writes */
8075                 lock_all_device_hash_locks_irq(conf);
8076                 /* '2' tells resync/reshape to pause so that all
8077                  * active stripes can drain
8078                  */
8079                 r5c_flush_cache(conf, INT_MAX);
8080                 conf->quiesce = 2;
8081                 wait_event_cmd(conf->wait_for_quiescent,
8082                                     atomic_read(&conf->active_stripes) == 0 &&
8083                                     atomic_read(&conf->active_aligned_reads) == 0,
8084                                     unlock_all_device_hash_locks_irq(conf),
8085                                     lock_all_device_hash_locks_irq(conf));
8086                 conf->quiesce = 1;
8087                 unlock_all_device_hash_locks_irq(conf);
8088                 /* allow reshape to continue */
8089                 wake_up(&conf->wait_for_overlap);
8090         } else {
8091                 /* re-enable writes */
8092                 lock_all_device_hash_locks_irq(conf);
8093                 conf->quiesce = 0;
8094                 wake_up(&conf->wait_for_quiescent);
8095                 wake_up(&conf->wait_for_overlap);
8096                 unlock_all_device_hash_locks_irq(conf);
8097         }
8098         log_quiesce(conf, quiesce);
8099 }
8100
8101 static void *raid45_takeover_raid0(struct mddev *mddev, int level)
8102 {
8103         struct r0conf *raid0_conf = mddev->private;
8104         sector_t sectors;
8105
8106         /* for raid0 takeover only one zone is supported */
8107         if (raid0_conf->nr_strip_zones > 1) {
8108                 pr_warn("md/raid:%s: cannot takeover raid0 with more than one zone.\n",
8109                         mdname(mddev));
8110                 return ERR_PTR(-EINVAL);
8111         }
8112
8113         sectors = raid0_conf->strip_zone[0].zone_end;
8114         sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
8115         mddev->dev_sectors = sectors;
8116         mddev->new_level = level;
8117         mddev->new_layout = ALGORITHM_PARITY_N;
8118         mddev->new_chunk_sectors = mddev->chunk_sectors;
8119         mddev->raid_disks += 1;
8120         mddev->delta_disks = 1;
8121         /* make sure it will be not marked as dirty */
8122         mddev->recovery_cp = MaxSector;
8123
8124         return setup_conf(mddev);
8125 }
8126
8127 static void *raid5_takeover_raid1(struct mddev *mddev)
8128 {
8129         int chunksect;
8130         void *ret;
8131
8132         if (mddev->raid_disks != 2 ||
8133             mddev->degraded > 1)
8134                 return ERR_PTR(-EINVAL);
8135
8136         /* Should check if there are write-behind devices? */
8137
8138         chunksect = 64*2; /* 64K by default */
8139
8140         /* The array must be an exact multiple of chunksize */
8141         while (chunksect && (mddev->array_sectors & (chunksect-1)))
8142                 chunksect >>= 1;
8143
8144         if ((chunksect<<9) < STRIPE_SIZE)
8145                 /* array size does not allow a suitable chunk size */
8146                 return ERR_PTR(-EINVAL);
8147
8148         mddev->new_level = 5;
8149         mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
8150         mddev->new_chunk_sectors = chunksect;
8151
8152         ret = setup_conf(mddev);
8153         if (!IS_ERR(ret))
8154                 mddev_clear_unsupported_flags(mddev,
8155                         UNSUPPORTED_MDDEV_FLAGS);
8156         return ret;
8157 }
8158
8159 static void *raid5_takeover_raid6(struct mddev *mddev)
8160 {
8161         int new_layout;
8162
8163         switch (mddev->layout) {
8164         case ALGORITHM_LEFT_ASYMMETRIC_6:
8165                 new_layout = ALGORITHM_LEFT_ASYMMETRIC;
8166                 break;
8167         case ALGORITHM_RIGHT_ASYMMETRIC_6:
8168                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
8169                 break;
8170         case ALGORITHM_LEFT_SYMMETRIC_6:
8171                 new_layout = ALGORITHM_LEFT_SYMMETRIC;
8172                 break;
8173         case ALGORITHM_RIGHT_SYMMETRIC_6:
8174                 new_layout = ALGORITHM_RIGHT_SYMMETRIC;
8175                 break;
8176         case ALGORITHM_PARITY_0_6:
8177                 new_layout = ALGORITHM_PARITY_0;
8178                 break;
8179         case ALGORITHM_PARITY_N:
8180                 new_layout = ALGORITHM_PARITY_N;
8181                 break;
8182         default:
8183                 return ERR_PTR(-EINVAL);
8184         }
8185         mddev->new_level = 5;
8186         mddev->new_layout = new_layout;
8187         mddev->delta_disks = -1;
8188         mddev->raid_disks -= 1;
8189         return setup_conf(mddev);
8190 }
8191
8192 static int raid5_check_reshape(struct mddev *mddev)
8193 {
8194         /* For a 2-drive array, the layout and chunk size can be changed
8195          * immediately as not restriping is needed.
8196          * For larger arrays we record the new value - after validation
8197          * to be used by a reshape pass.
8198          */
8199         struct r5conf *conf = mddev->private;
8200         int new_chunk = mddev->new_chunk_sectors;
8201
8202         if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
8203                 return -EINVAL;
8204         if (new_chunk > 0) {
8205                 if (!is_power_of_2(new_chunk))
8206                         return -EINVAL;
8207                 if (new_chunk < (PAGE_SIZE>>9))
8208                         return -EINVAL;
8209                 if (mddev->array_sectors & (new_chunk-1))
8210                         /* not factor of array size */
8211                         return -EINVAL;
8212         }
8213
8214         /* They look valid */
8215
8216         if (mddev->raid_disks == 2) {
8217                 /* can make the change immediately */
8218                 if (mddev->new_layout >= 0) {
8219                         conf->algorithm = mddev->new_layout;
8220                         mddev->layout = mddev->new_layout;
8221                 }
8222                 if (new_chunk > 0) {
8223                         conf->chunk_sectors = new_chunk ;
8224                         mddev->chunk_sectors = new_chunk;
8225                 }
8226                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8227                 md_wakeup_thread(mddev->thread);
8228         }
8229         return check_reshape(mddev);
8230 }
8231
8232 static int raid6_check_reshape(struct mddev *mddev)
8233 {
8234         int new_chunk = mddev->new_chunk_sectors;
8235
8236         if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
8237                 return -EINVAL;
8238         if (new_chunk > 0) {
8239                 if (!is_power_of_2(new_chunk))
8240                         return -EINVAL;
8241                 if (new_chunk < (PAGE_SIZE >> 9))
8242                         return -EINVAL;
8243                 if (mddev->array_sectors & (new_chunk-1))
8244                         /* not factor of array size */
8245                         return -EINVAL;
8246         }
8247
8248         /* They look valid */
8249         return check_reshape(mddev);
8250 }
8251
8252 static void *raid5_takeover(struct mddev *mddev)
8253 {
8254         /* raid5 can take over:
8255          *  raid0 - if there is only one strip zone - make it a raid4 layout
8256          *  raid1 - if there are two drives.  We need to know the chunk size
8257          *  raid4 - trivial - just use a raid4 layout.
8258          *  raid6 - Providing it is a *_6 layout
8259          */
8260         if (mddev->level == 0)
8261                 return raid45_takeover_raid0(mddev, 5);
8262         if (mddev->level == 1)
8263                 return raid5_takeover_raid1(mddev);
8264         if (mddev->level == 4) {
8265                 mddev->new_layout = ALGORITHM_PARITY_N;
8266                 mddev->new_level = 5;
8267                 return setup_conf(mddev);
8268         }
8269         if (mddev->level == 6)
8270                 return raid5_takeover_raid6(mddev);
8271
8272         return ERR_PTR(-EINVAL);
8273 }
8274
8275 static void *raid4_takeover(struct mddev *mddev)
8276 {
8277         /* raid4 can take over:
8278          *  raid0 - if there is only one strip zone
8279          *  raid5 - if layout is right
8280          */
8281         if (mddev->level == 0)
8282                 return raid45_takeover_raid0(mddev, 4);
8283         if (mddev->level == 5 &&
8284             mddev->layout == ALGORITHM_PARITY_N) {
8285                 mddev->new_layout = 0;
8286                 mddev->new_level = 4;
8287                 return setup_conf(mddev);
8288         }
8289         return ERR_PTR(-EINVAL);
8290 }
8291
8292 static struct md_personality raid5_personality;
8293
8294 static void *raid6_takeover(struct mddev *mddev)
8295 {
8296         /* Currently can only take over a raid5.  We map the
8297          * personality to an equivalent raid6 personality
8298          * with the Q block at the end.
8299          */
8300         int new_layout;
8301
8302         if (mddev->pers != &raid5_personality)
8303                 return ERR_PTR(-EINVAL);
8304         if (mddev->degraded > 1)
8305                 return ERR_PTR(-EINVAL);
8306         if (mddev->raid_disks > 253)
8307                 return ERR_PTR(-EINVAL);
8308         if (mddev->raid_disks < 3)
8309                 return ERR_PTR(-EINVAL);
8310
8311         switch (mddev->layout) {
8312         case ALGORITHM_LEFT_ASYMMETRIC:
8313                 new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
8314                 break;
8315         case ALGORITHM_RIGHT_ASYMMETRIC:
8316                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
8317                 break;
8318         case ALGORITHM_LEFT_SYMMETRIC:
8319                 new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
8320                 break;
8321         case ALGORITHM_RIGHT_SYMMETRIC:
8322                 new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
8323                 break;
8324         case ALGORITHM_PARITY_0:
8325                 new_layout = ALGORITHM_PARITY_0_6;
8326                 break;
8327         case ALGORITHM_PARITY_N:
8328                 new_layout = ALGORITHM_PARITY_N;
8329                 break;
8330         default:
8331                 return ERR_PTR(-EINVAL);
8332         }
8333         mddev->new_level = 6;
8334         mddev->new_layout = new_layout;
8335         mddev->delta_disks = 1;
8336         mddev->raid_disks += 1;
8337         return setup_conf(mddev);
8338 }
8339
8340 static int raid5_change_consistency_policy(struct mddev *mddev, const char *buf)
8341 {
8342         struct r5conf *conf;
8343         int err;
8344
8345         err = mddev_lock(mddev);
8346         if (err)
8347                 return err;
8348         conf = mddev->private;
8349         if (!conf) {
8350                 mddev_unlock(mddev);
8351                 return -ENODEV;
8352         }
8353
8354         if (strncmp(buf, "ppl", 3) == 0) {
8355                 /* ppl only works with RAID 5 */
8356                 if (!raid5_has_ppl(conf) && conf->level == 5) {
8357                         err = log_init(conf, NULL, true);
8358                         if (!err) {
8359                                 err = resize_stripes(conf, conf->pool_size);
8360                                 if (err)
8361                                         log_exit(conf);
8362                         }
8363                 } else
8364                         err = -EINVAL;
8365         } else if (strncmp(buf, "resync", 6) == 0) {
8366                 if (raid5_has_ppl(conf)) {
8367                         mddev_suspend(mddev);
8368                         log_exit(conf);
8369                         mddev_resume(mddev);
8370                         err = resize_stripes(conf, conf->pool_size);
8371                 } else if (test_bit(MD_HAS_JOURNAL, &conf->mddev->flags) &&
8372                            r5l_log_disk_error(conf)) {
8373                         bool journal_dev_exists = false;
8374                         struct md_rdev *rdev;
8375
8376                         rdev_for_each(rdev, mddev)
8377                                 if (test_bit(Journal, &rdev->flags)) {
8378                                         journal_dev_exists = true;
8379                                         break;
8380                                 }
8381
8382                         if (!journal_dev_exists) {
8383                                 mddev_suspend(mddev);
8384                                 clear_bit(MD_HAS_JOURNAL, &mddev->flags);
8385                                 mddev_resume(mddev);
8386                         } else  /* need remove journal device first */
8387                                 err = -EBUSY;
8388                 } else
8389                         err = -EINVAL;
8390         } else {
8391                 err = -EINVAL;
8392         }
8393
8394         if (!err)
8395                 md_update_sb(mddev, 1);
8396
8397         mddev_unlock(mddev);
8398
8399         return err;
8400 }
8401
8402 static int raid5_start(struct mddev *mddev)
8403 {
8404         struct r5conf *conf = mddev->private;
8405
8406         return r5l_start(conf->log);
8407 }
8408
8409 static struct md_personality raid6_personality =
8410 {
8411         .name           = "raid6",
8412         .level          = 6,
8413         .owner          = THIS_MODULE,
8414         .make_request   = raid5_make_request,
8415         .run            = raid5_run,
8416         .start          = raid5_start,
8417         .free           = raid5_free,
8418         .status         = raid5_status,
8419         .error_handler  = raid5_error,
8420         .hot_add_disk   = raid5_add_disk,
8421         .hot_remove_disk= raid5_remove_disk,
8422         .spare_active   = raid5_spare_active,
8423         .sync_request   = raid5_sync_request,
8424         .resize         = raid5_resize,
8425         .size           = raid5_size,
8426         .check_reshape  = raid6_check_reshape,
8427         .start_reshape  = raid5_start_reshape,
8428         .finish_reshape = raid5_finish_reshape,
8429         .quiesce        = raid5_quiesce,
8430         .takeover       = raid6_takeover,
8431         .congested      = raid5_congested,
8432         .change_consistency_policy = raid5_change_consistency_policy,
8433 };
8434 static struct md_personality raid5_personality =
8435 {
8436         .name           = "raid5",
8437         .level          = 5,
8438         .owner          = THIS_MODULE,
8439         .make_request   = raid5_make_request,
8440         .run            = raid5_run,
8441         .start          = raid5_start,
8442         .free           = raid5_free,
8443         .status         = raid5_status,
8444         .error_handler  = raid5_error,
8445         .hot_add_disk   = raid5_add_disk,
8446         .hot_remove_disk= raid5_remove_disk,
8447         .spare_active   = raid5_spare_active,
8448         .sync_request   = raid5_sync_request,
8449         .resize         = raid5_resize,
8450         .size           = raid5_size,
8451         .check_reshape  = raid5_check_reshape,
8452         .start_reshape  = raid5_start_reshape,
8453         .finish_reshape = raid5_finish_reshape,
8454         .quiesce        = raid5_quiesce,
8455         .takeover       = raid5_takeover,
8456         .congested      = raid5_congested,
8457         .change_consistency_policy = raid5_change_consistency_policy,
8458 };
8459
8460 static struct md_personality raid4_personality =
8461 {
8462         .name           = "raid4",
8463         .level          = 4,
8464         .owner          = THIS_MODULE,
8465         .make_request   = raid5_make_request,
8466         .run            = raid5_run,
8467         .start          = raid5_start,
8468         .free           = raid5_free,
8469         .status         = raid5_status,
8470         .error_handler  = raid5_error,
8471         .hot_add_disk   = raid5_add_disk,
8472         .hot_remove_disk= raid5_remove_disk,
8473         .spare_active   = raid5_spare_active,
8474         .sync_request   = raid5_sync_request,
8475         .resize         = raid5_resize,
8476         .size           = raid5_size,
8477         .check_reshape  = raid5_check_reshape,
8478         .start_reshape  = raid5_start_reshape,
8479         .finish_reshape = raid5_finish_reshape,
8480         .quiesce        = raid5_quiesce,
8481         .takeover       = raid4_takeover,
8482         .congested      = raid5_congested,
8483         .change_consistency_policy = raid5_change_consistency_policy,
8484 };
8485
8486 static int __init raid5_init(void)
8487 {
8488         int ret;
8489
8490         raid5_wq = alloc_workqueue("raid5wq",
8491                 WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE|WQ_SYSFS, 0);
8492         if (!raid5_wq)
8493                 return -ENOMEM;
8494
8495         ret = cpuhp_setup_state_multi(CPUHP_MD_RAID5_PREPARE,
8496                                       "md/raid5:prepare",
8497                                       raid456_cpu_up_prepare,
8498                                       raid456_cpu_dead);
8499         if (ret) {
8500                 destroy_workqueue(raid5_wq);
8501                 return ret;
8502         }
8503         register_md_personality(&raid6_personality);
8504         register_md_personality(&raid5_personality);
8505         register_md_personality(&raid4_personality);
8506         return 0;
8507 }
8508
8509 static void raid5_exit(void)
8510 {
8511         unregister_md_personality(&raid6_personality);
8512         unregister_md_personality(&raid5_personality);
8513         unregister_md_personality(&raid4_personality);
8514         cpuhp_remove_multi_state(CPUHP_MD_RAID5_PREPARE);
8515         destroy_workqueue(raid5_wq);
8516 }
8517
8518 module_init(raid5_init);
8519 module_exit(raid5_exit);
8520 MODULE_LICENSE("GPL");
8521 MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
8522 MODULE_ALIAS("md-personality-4"); /* RAID5 */
8523 MODULE_ALIAS("md-raid5");
8524 MODULE_ALIAS("md-raid4");
8525 MODULE_ALIAS("md-level-5");
8526 MODULE_ALIAS("md-level-4");
8527 MODULE_ALIAS("md-personality-8"); /* RAID6 */
8528 MODULE_ALIAS("md-raid6");
8529 MODULE_ALIAS("md-level-6");
8530
8531 /* This used to be two separate modules, they were: */
8532 MODULE_ALIAS("raid5");
8533 MODULE_ALIAS("raid6");