drivers/md/raid5.c

   1 /*
   2  * raid5.c : Multiple Devices driver for Linux
   3  *         Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
   4  *         Copyright (C) 1999, 2000 Ingo Molnar
   5  *         Copyright (C) 2002, 2003 H. Peter Anvin
   6  *
   7  * RAID-4/5/6 management functions.
   8  * Thanks to Penguin Computing for making the RAID-6 development possible
   9  * by donating a test server!
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2, or (at your option)
  14  * any later version.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * (for example /usr/src/linux/COPYING); if not, write to the Free
  18  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20
  21 /*
  22  * BITMAP UNPLUGGING:
  23  *
  24  * The sequencing for updating the bitmap reliably is a little
  25  * subtle (and I got it wrong the first time) so it deserves some
  26  * explanation.
  27  *
  28  * We group bitmap updates into batches.  Each batch has a number.
  29  * We may write out several batches at once, but that isn't very important.
  30  * conf->seq_write is the number of the last batch successfully written.
  31  * conf->seq_flush is the number of the last batch that was closed to
  32  *    new additions.
  33  * When we discover that we will need to write to any block in a stripe
  34  * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
  35  * the number of the batch it will be in. This is seq_flush+1.
  36  * When we are ready to do a write, if that batch hasn't been written yet,
  37  *   we plug the array and queue the stripe for later.
  38  * When an unplug happens, we increment bm_flush, thus closing the current
  39  *   batch.
  40  * When we notice that bm_flush > bm_write, we write out all pending updates
  41  * to the bitmap, and advance bm_write to where bm_flush was.
  42  * This may occasionally write a bit out twice, but is sure never to
  43  * miss any bits.
  44  */
  45
  46 #include <linux/blkdev.h>
  47 #include <linux/kthread.h>
  48 #include <linux/raid/pq.h>
  49 #include <linux/async_tx.h>
  50 #include <linux/module.h>
  51 #include <linux/async.h>
  52 #include <linux/seq_file.h>
  53 #include <linux/cpu.h>
  54 #include <linux/slab.h>
  55 #include <linux/ratelimit.h>
  56 #include <linux/nodemask.h>
  57 #include <linux/flex_array.h>
  58 #include <linux/sched/signal.h>
  59
  60 #include <trace/events/block.h>
  61 #include <linux/list_sort.h>
  62
  63 #include "md.h"
  64 #include "raid5.h"
  65 #include "raid0.h"
  66 #include "bitmap.h"
  67 #include "raid5-log.h"
  68
  69 #define UNSUPPORTED_MDDEV_FLAGS (1L << MD_FAILFAST_SUPPORTED)
  70
  71 #define cpu_to_group(cpu) cpu_to_node(cpu)
  72 #define ANY_GROUP NUMA_NO_NODE
  73
  74 static bool devices_handle_discard_safely = false;
  75 module_param(devices_handle_discard_safely, bool, 0644);
  76 MODULE_PARM_DESC(devices_handle_discard_safely,
  77                  "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
  78 static struct workqueue_struct *raid5_wq;
  79
  80 static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
  81 {
  82         int hash = (sect >> STRIPE_SHIFT) & HASH_MASK;
  83         return &conf->stripe_hashtbl[hash];
  84 }
  85
  86 static inline int stripe_hash_locks_hash(sector_t sect)
  87 {
  88         return (sect >> STRIPE_SHIFT) & STRIPE_HASH_LOCKS_MASK;
  89 }
  90
  91 static inline void lock_device_hash_lock(struct r5conf *conf, int hash)
  92 {
  93         spin_lock_irq(conf->hash_locks + hash);
  94         spin_lock(&conf->device_lock);
  95 }
  96
  97 static inline void unlock_device_hash_lock(struct r5conf *conf, int hash)
  98 {
  99         spin_unlock(&conf->device_lock);
 100         spin_unlock_irq(conf->hash_locks + hash);
 101 }
 102
 103 static inline void lock_all_device_hash_locks_irq(struct r5conf *conf)
 104 {
 105         int i;
 106         local_irq_disable();
 107         spin_lock(conf->hash_locks);
 108         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
 109                 spin_lock_nest_lock(conf->hash_locks + i, conf->hash_locks);
 110         spin_lock(&conf->device_lock);
 111 }
 112
 113 static inline void unlock_all_device_hash_locks_irq(struct r5conf *conf)
 114 {
 115         int i;
 116         spin_unlock(&conf->device_lock);
 117         for (i = NR_STRIPE_HASH_LOCKS; i; i--)
 118                 spin_unlock(conf->hash_locks + i - 1);
 119         local_irq_enable();
 120 }
 121
 122 /* Find first data disk in a raid6 stripe */
 123 static inline int raid6_d0(struct stripe_head *sh)
 124 {
 125         if (sh->ddf_layout)
 126                 /* ddf always start from first device */
 127                 return 0;
 128         /* md starts just after Q block */
 129         if (sh->qd_idx == sh->disks - 1)
 130                 return 0;
 131         else
 132                 return sh->qd_idx + 1;
 133 }
 134 static inline int raid6_next_disk(int disk, int raid_disks)
 135 {
 136         disk++;
 137         return (disk < raid_disks) ? disk : 0;
 138 }
 139
 140 /* When walking through the disks in a raid5, starting at raid6_d0,
 141  * We need to map each disk to a 'slot', where the data disks are slot
 142  * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
 143  * is raid_disks-1.  This help does that mapping.
 144  */
 145 static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
 146                              int *count, int syndrome_disks)
 147 {
 148         int slot = *count;
 149
 150         if (sh->ddf_layout)
 151                 (*count)++;
 152         if (idx == sh->pd_idx)
 153                 return syndrome_disks;
 154         if (idx == sh->qd_idx)
 155                 return syndrome_disks + 1;
 156         if (!sh->ddf_layout)
 157                 (*count)++;
 158         return slot;
 159 }
 160
 161 static void print_raid5_conf (struct r5conf *conf);
 162
 163 static int stripe_operations_active(struct stripe_head *sh)
 164 {
 165         return sh->check_state || sh->reconstruct_state ||
 166                test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
 167                test_bit(STRIPE_COMPUTE_RUN, &sh->state);
 168 }
 169
 170 static bool stripe_is_lowprio(struct stripe_head *sh)
 171 {
 172         return (test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) ||
 173                 test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) &&
 174                !test_bit(STRIPE_R5C_CACHING, &sh->state);
 175 }
 176
 177 static void raid5_wakeup_stripe_thread(struct stripe_head *sh)
 178 {
 179         struct r5conf *conf = sh->raid_conf;
 180         struct r5worker_group *group;
 181         int thread_cnt;
 182         int i, cpu = sh->cpu;
 183
 184         if (!cpu_online(cpu)) {
 185                 cpu = cpumask_any(cpu_online_mask);
 186                 sh->cpu = cpu;
 187         }
 188
 189         if (list_empty(&sh->lru)) {
 190                 struct r5worker_group *group;
 191                 group = conf->worker_groups + cpu_to_group(cpu);
 192                 if (stripe_is_lowprio(sh))
 193                         list_add_tail(&sh->lru, &group->loprio_list);
 194                 else
 195                         list_add_tail(&sh->lru, &group->handle_list);
 196                 group->stripes_cnt++;
 197                 sh->group = group;
 198         }
 199
 200         if (conf->worker_cnt_per_group == 0) {
 201                 md_wakeup_thread(conf->mddev->thread);
 202                 return;
 203         }
 204
 205         group = conf->worker_groups + cpu_to_group(sh->cpu);
 206
 207         group->workers[0].working = true;
 208         /* at least one worker should run to avoid race */
 209         queue_work_on(sh->cpu, raid5_wq, &group->workers[0].work);
 210
 211         thread_cnt = group->stripes_cnt / MAX_STRIPE_BATCH - 1;
 212         /* wakeup more workers */
 213         for (i = 1; i < conf->worker_cnt_per_group && thread_cnt > 0; i++) {
 214                 if (group->workers[i].working == false) {
 215                         group->workers[i].working = true;
 216                         queue_work_on(sh->cpu, raid5_wq,
 217                                       &group->workers[i].work);
 218                         thread_cnt--;
 219                 }
 220         }
 221 }
 222
 223 static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh,
 224                               struct list_head *temp_inactive_list)
 225 {
 226         int i;
 227         int injournal = 0;      /* number of date pages with R5_InJournal */
 228
 229         BUG_ON(!list_empty(&sh->lru));
 230         BUG_ON(atomic_read(&conf->active_stripes)==0);
 231
 232         if (r5c_is_writeback(conf->log))
 233                 for (i = sh->disks; i--; )
 234                         if (test_bit(R5_InJournal, &sh->dev[i].flags))
 235                                 injournal++;
 236         /*
 237          * When quiesce in r5c write back, set STRIPE_HANDLE for stripes with
 238          * data in journal, so they are not released to cached lists
 239          */
 240         if (conf->quiesce && r5c_is_writeback(conf->log) &&
 241             !test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0) {
 242                 if (test_bit(STRIPE_R5C_CACHING, &sh->state))
 243                         r5c_make_stripe_write_out(sh);
 244                 set_bit(STRIPE_HANDLE, &sh->state);
 245         }
 246
 247         if (test_bit(STRIPE_HANDLE, &sh->state)) {
 248                 if (test_bit(STRIPE_DELAYED, &sh->state) &&
 249                     !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 250                         list_add_tail(&sh->lru, &conf->delayed_list);
 251                 else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
 252                            sh->bm_seq - conf->seq_write > 0)
 253                         list_add_tail(&sh->lru, &conf->bitmap_list);
 254                 else {
 255                         clear_bit(STRIPE_DELAYED, &sh->state);
 256                         clear_bit(STRIPE_BIT_DELAY, &sh->state);
 257                         if (conf->worker_cnt_per_group == 0) {
 258                                 if (stripe_is_lowprio(sh))
 259                                         list_add_tail(&sh->lru,
 260                                                         &conf->loprio_list);
 261                                 else
 262                                         list_add_tail(&sh->lru,
 263                                                         &conf->handle_list);
 264                         } else {
 265                                 raid5_wakeup_stripe_thread(sh);
 266                                 return;
 267                         }
 268                 }
 269                 md_wakeup_thread(conf->mddev->thread);
 270         } else {
 271                 BUG_ON(stripe_operations_active(sh));
 272                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 273                         if (atomic_dec_return(&conf->preread_active_stripes)
 274                             < IO_THRESHOLD)
 275                                 md_wakeup_thread(conf->mddev->thread);
 276                 atomic_dec(&conf->active_stripes);
 277                 if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
 278                         if (!r5c_is_writeback(conf->log))
 279                                 list_add_tail(&sh->lru, temp_inactive_list);
 280                         else {
 281                                 WARN_ON(test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags));
 282                                 if (injournal == 0)
 283                                         list_add_tail(&sh->lru, temp_inactive_list);
 284                                 else if (injournal == conf->raid_disks - conf->max_degraded) {
 285                                         /* full stripe */
 286                                         if (!test_and_set_bit(STRIPE_R5C_FULL_STRIPE, &sh->state))
 287                                                 atomic_inc(&conf->r5c_cached_full_stripes);
 288                                         if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
 289                                                 atomic_dec(&conf->r5c_cached_partial_stripes);
 290                                         list_add_tail(&sh->lru, &conf->r5c_full_stripe_list);
 291                                         r5c_check_cached_full_stripe(conf);
 292                                 } else
 293                                         /*
 294                                          * STRIPE_R5C_PARTIAL_STRIPE is set in
 295                                          * r5c_try_caching_write(). No need to
 296                                          * set it again.
 297                                          */
 298                                         list_add_tail(&sh->lru, &conf->r5c_partial_stripe_list);
 299                         }
 300                 }
 301         }
 302 }
 303
 304 static void __release_stripe(struct r5conf *conf, struct stripe_head *sh,
 305                              struct list_head *temp_inactive_list)
 306 {
 307         if (atomic_dec_and_test(&sh->count))
 308                 do_release_stripe(conf, sh, temp_inactive_list);
 309 }
 310
 311 /*
 312  * @hash could be NR_STRIPE_HASH_LOCKS, then we have a list of inactive_list
 313  *
 314  * Be careful: Only one task can add/delete stripes from temp_inactive_list at
 315  * given time. Adding stripes only takes device lock, while deleting stripes
 316  * only takes hash lock.
 317  */
 318 static void release_inactive_stripe_list(struct r5conf *conf,
 319                                          struct list_head *temp_inactive_list,
 320                                          int hash)
 321 {
 322         int size;
 323         bool do_wakeup = false;
 324         unsigned long flags;
 325
 326         if (hash == NR_STRIPE_HASH_LOCKS) {
 327                 size = NR_STRIPE_HASH_LOCKS;
 328                 hash = NR_STRIPE_HASH_LOCKS - 1;
 329         } else
 330                 size = 1;
 331         while (size) {
 332                 struct list_head *list = &temp_inactive_list[size - 1];
 333
 334                 /*
 335                  * We don't hold any lock here yet, raid5_get_active_stripe() might
 336                  * remove stripes from the list
 337                  */
 338                 if (!list_empty_careful(list)) {
 339                         spin_lock_irqsave(conf->hash_locks + hash, flags);
 340                         if (list_empty(conf->inactive_list + hash) &&
 341                             !list_empty(list))
 342                                 atomic_dec(&conf->empty_inactive_list_nr);
 343                         list_splice_tail_init(list, conf->inactive_list + hash);
 344                         do_wakeup = true;
 345                         spin_unlock_irqrestore(conf->hash_locks + hash, flags);
 346                 }
 347                 size--;
 348                 hash--;
 349         }
 350
 351         if (do_wakeup) {
 352                 wake_up(&conf->wait_for_stripe);
 353                 if (atomic_read(&conf->active_stripes) == 0)
 354                         wake_up(&conf->wait_for_quiescent);
 355                 if (conf->retry_read_aligned)
 356                         md_wakeup_thread(conf->mddev->thread);
 357         }
 358 }
 359
 360 /* should hold conf->device_lock already */
 361 static int release_stripe_list(struct r5conf *conf,
 362                                struct list_head *temp_inactive_list)
 363 {
 364         struct stripe_head *sh, *t;
 365         int count = 0;
 366         struct llist_node *head;
 367
 368         head = llist_del_all(&conf->released_stripes);
 369         head = llist_reverse_order(head);
 370         llist_for_each_entry_safe(sh, t, head, release_list) {
 371                 int hash;
 372
 373                 /* sh could be readded after STRIPE_ON_RELEASE_LIST is cleard */
 374                 smp_mb();
 375                 clear_bit(STRIPE_ON_RELEASE_LIST, &sh->state);
 376                 /*
 377                  * Don't worry the bit is set here, because if the bit is set
 378                  * again, the count is always > 1. This is true for
 379                  * STRIPE_ON_UNPLUG_LIST bit too.
 380                  */
 381                 hash = sh->hash_lock_index;
 382                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
 383                 count++;
 384         }
 385
 386         return count;
 387 }
 388
 389 void raid5_release_stripe(struct stripe_head *sh)
 390 {
 391         struct r5conf *conf = sh->raid_conf;
 392         unsigned long flags;
 393         struct list_head list;
 394         int hash;
 395         bool wakeup;
 396
 397         /* Avoid release_list until the last reference.
 398          */
 399         if (atomic_add_unless(&sh->count, -1, 1))
 400                 return;
 401
 402         if (unlikely(!conf->mddev->thread) ||
 403                 test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state))
 404                 goto slow_path;
 405         wakeup = llist_add(&sh->release_list, &conf->released_stripes);
 406         if (wakeup)
 407                 md_wakeup_thread(conf->mddev->thread);
 408         return;
 409 slow_path:
 410         local_irq_save(flags);
 411         /* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */
 412         if (atomic_dec_and_lock(&sh->count, &conf->device_lock)) {
 413                 INIT_LIST_HEAD(&list);
 414                 hash = sh->hash_lock_index;
 415                 do_release_stripe(conf, sh, &list);
 416                 spin_unlock(&conf->device_lock);
 417                 release_inactive_stripe_list(conf, &list, hash);
 418         }
 419         local_irq_restore(flags);
 420 }
 421
 422 static inline void remove_hash(struct stripe_head *sh)
 423 {
 424         pr_debug("remove_hash(), stripe %llu\n",
 425                 (unsigned long long)sh->sector);
 426
 427         hlist_del_init(&sh->hash);
 428 }
 429
 430 static inline void insert_hash(struct r5conf *conf, struct stripe_head *sh)
 431 {
 432         struct hlist_head *hp = stripe_hash(conf, sh->sector);
 433
 434         pr_debug("insert_hash(), stripe %llu\n",
 435                 (unsigned long long)sh->sector);
 436
 437         hlist_add_head(&sh->hash, hp);
 438 }
 439
 440 /* find an idle stripe, make sure it is unhashed, and return it. */
 441 static struct stripe_head *get_free_stripe(struct r5conf *conf, int hash)
 442 {
 443         struct stripe_head *sh = NULL;
 444         struct list_head *first;
 445
 446         if (list_empty(conf->inactive_list + hash))
 447                 goto out;
 448         first = (conf->inactive_list + hash)->next;
 449         sh = list_entry(first, struct stripe_head, lru);
 450         list_del_init(first);
 451         remove_hash(sh);
 452         atomic_inc(&conf->active_stripes);
 453         BUG_ON(hash != sh->hash_lock_index);
 454         if (list_empty(conf->inactive_list + hash))
 455                 atomic_inc(&conf->empty_inactive_list_nr);
 456 out:
 457         return sh;
 458 }
 459
 460 static void shrink_buffers(struct stripe_head *sh)
 461 {
 462         struct page *p;
 463         int i;
 464         int num = sh->raid_conf->pool_size;
 465
 466         for (i = 0; i < num ; i++) {
 467                 WARN_ON(sh->dev[i].page != sh->dev[i].orig_page);
 468                 p = sh->dev[i].page;
 469                 if (!p)
 470                         continue;
 471                 sh->dev[i].page = NULL;
 472                 put_page(p);
 473         }
 474 }
 475
 476 static int grow_buffers(struct stripe_head *sh, gfp_t gfp)
 477 {
 478         int i;
 479         int num = sh->raid_conf->pool_size;
 480
 481         for (i = 0; i < num; i++) {
 482                 struct page *page;
 483
 484                 if (!(page = alloc_page(gfp))) {
 485                         return 1;
 486                 }
 487                 sh->dev[i].page = page;
 488                 sh->dev[i].orig_page = page;
 489         }
 490
 491         return 0;
 492 }
 493
 494 static void raid5_build_block(struct stripe_head *sh, int i, int previous);
 495 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
 496                             struct stripe_head *sh);
 497
 498 static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
 499 {
 500         struct r5conf *conf = sh->raid_conf;
 501         int i, seq;
 502
 503         BUG_ON(atomic_read(&sh->count) != 0);
 504         BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
 505         BUG_ON(stripe_operations_active(sh));
 506         BUG_ON(sh->batch_head);
 507
 508         pr_debug("init_stripe called, stripe %llu\n",
 509                 (unsigned long long)sector);
 510 retry:
 511         seq = read_seqcount_begin(&conf->gen_lock);
 512         sh->generation = conf->generation - previous;
 513         sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
 514         sh->sector = sector;
 515         stripe_set_idx(sector, conf, previous, sh);
 516         sh->state = 0;
 517
 518         for (i = sh->disks; i--; ) {
 519                 struct r5dev *dev = &sh->dev[i];
 520
 521                 if (dev->toread || dev->read || dev->towrite || dev->written ||
 522                     test_bit(R5_LOCKED, &dev->flags)) {
 523                         pr_err("sector=%llx i=%d %p %p %p %p %d\n",
 524                                (unsigned long long)sh->sector, i, dev->toread,
 525                                dev->read, dev->towrite, dev->written,
 526                                test_bit(R5_LOCKED, &dev->flags));
 527                         WARN_ON(1);
 528                 }
 529                 dev->flags = 0;
 530                 raid5_build_block(sh, i, previous);
 531         }
 532         if (read_seqcount_retry(&conf->gen_lock, seq))
 533                 goto retry;
 534         sh->overwrite_disks = 0;
 535         insert_hash(conf, sh);
 536         sh->cpu = smp_processor_id();
 537         set_bit(STRIPE_BATCH_READY, &sh->state);
 538 }
 539
 540 static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
 541                                          short generation)
 542 {
 543         struct stripe_head *sh;
 544
 545         pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
 546         hlist_for_each_entry(sh, stripe_hash(conf, sector), hash)
 547                 if (sh->sector == sector && sh->generation == generation)
 548                         return sh;
 549         pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
 550         return NULL;
 551 }
 552
 553 /*
 554  * Need to check if array has failed when deciding whether to:
 555  *  - start an array
 556  *  - remove non-faulty devices
 557  *  - add a spare
 558  *  - allow a reshape
 559  * This determination is simple when no reshape is happening.
 560  * However if there is a reshape, we need to carefully check
 561  * both the before and after sections.
 562  * This is because some failed devices may only affect one
 563  * of the two sections, and some non-in_sync devices may
 564  * be insync in the section most affected by failed devices.
 565  */
 566 int raid5_calc_degraded(struct r5conf *conf)
 567 {
 568         int degraded, degraded2;
 569         int i;
 570
 571         rcu_read_lock();
 572         degraded = 0;
 573         for (i = 0; i < conf->previous_raid_disks; i++) {
 574                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 575                 if (rdev && test_bit(Faulty, &rdev->flags))
 576                         rdev = rcu_dereference(conf->disks[i].replacement);
 577                 if (!rdev || test_bit(Faulty, &rdev->flags))
 578                         degraded++;
 579                 else if (test_bit(In_sync, &rdev->flags))
 580                         ;
 581                 else
 582                         /* not in-sync or faulty.
 583                          * If the reshape increases the number of devices,
 584                          * this is being recovered by the reshape, so
 585                          * this 'previous' section is not in_sync.
 586                          * If the number of devices is being reduced however,
 587                          * the device can only be part of the array if
 588                          * we are reverting a reshape, so this section will
 589                          * be in-sync.
 590                          */
 591                         if (conf->raid_disks >= conf->previous_raid_disks)
 592                                 degraded++;
 593         }
 594         rcu_read_unlock();
 595         if (conf->raid_disks == conf->previous_raid_disks)
 596                 return degraded;
 597         rcu_read_lock();
 598         degraded2 = 0;
 599         for (i = 0; i < conf->raid_disks; i++) {
 600                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 601                 if (rdev && test_bit(Faulty, &rdev->flags))
 602                         rdev = rcu_dereference(conf->disks[i].replacement);
 603                 if (!rdev || test_bit(Faulty, &rdev->flags))
 604                         degraded2++;
 605                 else if (test_bit(In_sync, &rdev->flags))
 606                         ;
 607                 else
 608                         /* not in-sync or faulty.
 609                          * If reshape increases the number of devices, this
 610                          * section has already been recovered, else it
 611                          * almost certainly hasn't.
 612                          */
 613                         if (conf->raid_disks <= conf->previous_raid_disks)
 614                                 degraded2++;
 615         }
 616         rcu_read_unlock();
 617         if (degraded2 > degraded)
 618                 return degraded2;
 619         return degraded;
 620 }
 621
 622 static int has_failed(struct r5conf *conf)
 623 {
 624         int degraded;
 625
 626         if (conf->mddev->reshape_position == MaxSector)
 627                 return conf->mddev->degraded > conf->max_degraded;
 628
 629         degraded = raid5_calc_degraded(conf);
 630         if (degraded > conf->max_degraded)
 631                 return 1;
 632         return 0;
 633 }
 634
 635 struct stripe_head *
 636 raid5_get_active_stripe(struct r5conf *conf, sector_t sector,
 637                         int previous, int noblock, int noquiesce)
 638 {
 639         struct stripe_head *sh;
 640         int hash = stripe_hash_locks_hash(sector);
 641         int inc_empty_inactive_list_flag;
 642
 643         pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
 644
 645         spin_lock_irq(conf->hash_locks + hash);
 646
 647         do {
 648                 wait_event_lock_irq(conf->wait_for_quiescent,
 649                                     conf->quiesce == 0 || noquiesce,
 650                                     *(conf->hash_locks + hash));
 651                 sh = __find_stripe(conf, sector, conf->generation - previous);
 652                 if (!sh) {
 653                         if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state)) {
 654                                 sh = get_free_stripe(conf, hash);
 655                                 if (!sh && !test_bit(R5_DID_ALLOC,
 656                                                      &conf->cache_state))
 657                                         set_bit(R5_ALLOC_MORE,
 658                                                 &conf->cache_state);
 659                         }
 660                         if (noblock && sh == NULL)
 661                                 break;
 662
 663                         r5c_check_stripe_cache_usage(conf);
 664                         if (!sh) {
 665                                 set_bit(R5_INACTIVE_BLOCKED,
 666                                         &conf->cache_state);
 667                                 r5l_wake_reclaim(conf->log, 0);
 668                                 wait_event_lock_irq(
 669                                         conf->wait_for_stripe,
 670                                         !list_empty(conf->inactive_list + hash) &&
 671                                         (atomic_read(&conf->active_stripes)
 672                                          < (conf->max_nr_stripes * 3 / 4)
 673                                          || !test_bit(R5_INACTIVE_BLOCKED,
 674                                                       &conf->cache_state)),
 675                                         *(conf->hash_locks + hash));
 676                                 clear_bit(R5_INACTIVE_BLOCKED,
 677                                           &conf->cache_state);
 678                         } else {
 679                                 init_stripe(sh, sector, previous);
 680                                 atomic_inc(&sh->count);
 681                         }
 682                 } else if (!atomic_inc_not_zero(&sh->count)) {
 683                         spin_lock(&conf->device_lock);
 684                         if (!atomic_read(&sh->count)) {
 685                                 if (!test_bit(STRIPE_HANDLE, &sh->state))
 686                                         atomic_inc(&conf->active_stripes);
 687                                 BUG_ON(list_empty(&sh->lru) &&
 688                                        !test_bit(STRIPE_EXPANDING, &sh->state));
 689                                 inc_empty_inactive_list_flag = 0;
 690                                 if (!list_empty(conf->inactive_list + hash))
 691                                         inc_empty_inactive_list_flag = 1;
 692                                 list_del_init(&sh->lru);
 693                                 if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 694                                         atomic_inc(&conf->empty_inactive_list_nr);
 695                                 if (sh->group) {
 696                                         sh->group->stripes_cnt--;
 697                                         sh->group = NULL;
 698                                 }
 699                         }
 700                         atomic_inc(&sh->count);
 701                         spin_unlock(&conf->device_lock);
 702                 }
 703         } while (sh == NULL);
 704
 705         spin_unlock_irq(conf->hash_locks + hash);
 706         return sh;
 707 }
 708
 709 static bool is_full_stripe_write(struct stripe_head *sh)
 710 {
 711         BUG_ON(sh->overwrite_disks > (sh->disks - sh->raid_conf->max_degraded));
 712         return sh->overwrite_disks == (sh->disks - sh->raid_conf->max_degraded);
 713 }
 714
 715 static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 716 {
 717         local_irq_disable();
 718         if (sh1 > sh2) {
 719                 spin_lock(&sh2->stripe_lock);
 720                 spin_lock_nested(&sh1->stripe_lock, 1);
 721         } else {
 722                 spin_lock(&sh1->stripe_lock);
 723                 spin_lock_nested(&sh2->stripe_lock, 1);
 724         }
 725 }
 726
 727 static void unlock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 728 {
 729         spin_unlock(&sh1->stripe_lock);
 730         spin_unlock(&sh2->stripe_lock);
 731         local_irq_enable();
 732 }
 733
 734 /* Only freshly new full stripe normal write stripe can be added to a batch list */
 735 static bool stripe_can_batch(struct stripe_head *sh)
 736 {
 737         struct r5conf *conf = sh->raid_conf;
 738
 739         if (conf->log || raid5_has_ppl(conf))
 740                 return false;
 741         return test_bit(STRIPE_BATCH_READY, &sh->state) &&
 742                 !test_bit(STRIPE_BITMAP_PENDING, &sh->state) &&
 743                 is_full_stripe_write(sh);
 744 }
 745
 746 /* we only do back search */
 747 static void stripe_add_to_batch_list(struct r5conf *conf, struct stripe_head *sh)
 748 {
 749         struct stripe_head *head;
 750         sector_t head_sector, tmp_sec;
 751         int hash;
 752         int dd_idx;
 753         int inc_empty_inactive_list_flag;
 754
 755         /* Don't cross chunks, so stripe pd_idx/qd_idx is the same */
 756         tmp_sec = sh->sector;
 757         if (!sector_div(tmp_sec, conf->chunk_sectors))
 758                 return;
 759         head_sector = sh->sector - STRIPE_SECTORS;
 760
 761         hash = stripe_hash_locks_hash(head_sector);
 762         spin_lock_irq(conf->hash_locks + hash);
 763         head = __find_stripe(conf, head_sector, conf->generation);
 764         if (head && !atomic_inc_not_zero(&head->count)) {
 765                 spin_lock(&conf->device_lock);
 766                 if (!atomic_read(&head->count)) {
 767                         if (!test_bit(STRIPE_HANDLE, &head->state))
 768                                 atomic_inc(&conf->active_stripes);
 769                         BUG_ON(list_empty(&head->lru) &&
 770                                !test_bit(STRIPE_EXPANDING, &head->state));
 771                         inc_empty_inactive_list_flag = 0;
 772                         if (!list_empty(conf->inactive_list + hash))
 773                                 inc_empty_inactive_list_flag = 1;
 774                         list_del_init(&head->lru);
 775                         if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 776                                 atomic_inc(&conf->empty_inactive_list_nr);
 777                         if (head->group) {
 778                                 head->group->stripes_cnt--;
 779                                 head->group = NULL;
 780                         }
 781                 }
 782                 atomic_inc(&head->count);
 783                 spin_unlock(&conf->device_lock);
 784         }
 785         spin_unlock_irq(conf->hash_locks + hash);
 786
 787         if (!head)
 788                 return;
 789         if (!stripe_can_batch(head))
 790                 goto out;
 791
 792         lock_two_stripes(head, sh);
 793         /* clear_batch_ready clear the flag */
 794         if (!stripe_can_batch(head) || !stripe_can_batch(sh))
 795                 goto unlock_out;
 796
 797         if (sh->batch_head)
 798                 goto unlock_out;
 799
 800         dd_idx = 0;
 801         while (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
 802                 dd_idx++;
 803         if (head->dev[dd_idx].towrite->bi_opf != sh->dev[dd_idx].towrite->bi_opf ||
 804             bio_op(head->dev[dd_idx].towrite) != bio_op(sh->dev[dd_idx].towrite))
 805                 goto unlock_out;
 806
 807         if (head->batch_head) {
 808                 spin_lock(&head->batch_head->batch_lock);
 809                 /* This batch list is already running */
 810                 if (!stripe_can_batch(head)) {
 811                         spin_unlock(&head->batch_head->batch_lock);
 812                         goto unlock_out;
 813                 }
 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
 822                 sh->batch_head = head->batch_head;
 823         } else {
 824                 head->batch_head = head;
 825                 sh->batch_head = head->batch_head;
 826                 spin_lock(&head->batch_lock);
 827                 list_add_tail(&sh->batch_list, &head->batch_list);
 828                 spin_unlock(&head->batch_lock);
 829         }
 830
 831         if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 832                 if (atomic_dec_return(&conf->preread_active_stripes)
 833                     < IO_THRESHOLD)
 834                         md_wakeup_thread(conf->mddev->thread);
 835
 836         if (test_and_clear_bit(STRIPE_BIT_DELAY, &sh->state)) {
 837                 int seq = sh->bm_seq;
 838                 if (test_bit(STRIPE_BIT_DELAY, &sh->batch_head->state) &&
 839                     sh->batch_head->bm_seq > seq)
 840                         seq = sh->batch_head->bm_seq;
 841                 set_bit(STRIPE_BIT_DELAY, &sh->batch_head->state);
 842                 sh->batch_head->bm_seq = seq;
 843         }
 844
 845         atomic_inc(&sh->count);
 846 unlock_out:
 847         unlock_two_stripes(head, sh);
 848 out:
 849         raid5_release_stripe(head);
 850 }
 851
 852 /* Determine if 'data_offset' or 'new_data_offset' should be used
 853  * in this stripe_head.
 854  */
 855 static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
 856 {
 857         sector_t progress = conf->reshape_progress;
 858         /* Need a memory barrier to make sure we see the value
 859          * of conf->generation, or ->data_offset that was set before
 860          * reshape_progress was updated.
 861          */
 862         smp_rmb();
 863         if (progress == MaxSector)
 864                 return 0;
 865         if (sh->generation == conf->generation - 1)
 866                 return 0;
 867         /* We are in a reshape, and this is a new-generation stripe,
 868          * so use new_data_offset.
 869          */
 870         return 1;
 871 }
 872
 873 static void dispatch_bio_list(struct bio_list *tmp)
 874 {
 875         struct bio *bio;
 876
 877         while ((bio = bio_list_pop(tmp)))
 878                 generic_make_request(bio);
 879 }
 880
 881 static int cmp_stripe(void *priv, struct list_head *a, struct list_head *b)
 882 {
 883         const struct r5pending_data *da = list_entry(a,
 884                                 struct r5pending_data, sibling);
 885         const struct r5pending_data *db = list_entry(b,
 886                                 struct r5pending_data, sibling);
 887         if (da->sector > db->sector)
 888                 return 1;
 889         if (da->sector < db->sector)
 890                 return -1;
 891         return 0;
 892 }
 893
 894 static void dispatch_defer_bios(struct r5conf *conf, int target,
 895                                 struct bio_list *list)
 896 {
 897         struct r5pending_data *data;
 898         struct list_head *first, *next = NULL;
 899         int cnt = 0;
 900
 901         if (conf->pending_data_cnt == 0)
 902                 return;
 903
 904         list_sort(NULL, &conf->pending_list, cmp_stripe);
 905
 906         first = conf->pending_list.next;
 907
 908         /* temporarily move the head */
 909         if (conf->next_pending_data)
 910                 list_move_tail(&conf->pending_list,
 911                                 &conf->next_pending_data->sibling);
 912
 913         while (!list_empty(&conf->pending_list)) {
 914                 data = list_first_entry(&conf->pending_list,
 915                         struct r5pending_data, sibling);
 916                 if (&data->sibling == first)
 917                         first = data->sibling.next;
 918                 next = data->sibling.next;
 919
 920                 bio_list_merge(list, &data->bios);
 921                 list_move(&data->sibling, &conf->free_list);
 922                 cnt++;
 923                 if (cnt >= target)
 924                         break;
 925         }
 926         conf->pending_data_cnt -= cnt;
 927         BUG_ON(conf->pending_data_cnt < 0 || cnt < target);
 928
 929         if (next != &conf->pending_list)
 930                 conf->next_pending_data = list_entry(next,
 931                                 struct r5pending_data, sibling);
 932         else
 933                 conf->next_pending_data = NULL;
 934         /* list isn't empty */
 935         if (first != &conf->pending_list)
 936                 list_move_tail(&conf->pending_list, first);
 937 }
 938
 939 static void flush_deferred_bios(struct r5conf *conf)
 940 {
 941         struct bio_list tmp = BIO_EMPTY_LIST;
 942
 943         if (conf->pending_data_cnt == 0)
 944                 return;
 945
 946         spin_lock(&conf->pending_bios_lock);
 947         dispatch_defer_bios(conf, conf->pending_data_cnt, &tmp);
 948         BUG_ON(conf->pending_data_cnt != 0);
 949         spin_unlock(&conf->pending_bios_lock);
 950
 951         dispatch_bio_list(&tmp);
 952 }
 953
 954 static void defer_issue_bios(struct r5conf *conf, sector_t sector,
 955                                 struct bio_list *bios)
 956 {
 957         struct bio_list tmp = BIO_EMPTY_LIST;
 958         struct r5pending_data *ent;
 959
 960         spin_lock(&conf->pending_bios_lock);
 961         ent = list_first_entry(&conf->free_list, struct r5pending_data,
 962                                                         sibling);
 963         list_move_tail(&ent->sibling, &conf->pending_list);
 964         ent->sector = sector;
 965         bio_list_init(&ent->bios);
 966         bio_list_merge(&ent->bios, bios);
 967         conf->pending_data_cnt++;
 968         if (conf->pending_data_cnt >= PENDING_IO_MAX)
 969                 dispatch_defer_bios(conf, PENDING_IO_ONE_FLUSH, &tmp);
 970
 971         spin_unlock(&conf->pending_bios_lock);
 972
 973         dispatch_bio_list(&tmp);
 974 }
 975
 976 static void
 977 raid5_end_read_request(struct bio *bi);
 978 static void
 979 raid5_end_write_request(struct bio *bi);
 980
 981 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 982 {
 983         struct r5conf *conf = sh->raid_conf;
 984         int i, disks = sh->disks;
 985         struct stripe_head *head_sh = sh;
 986         struct bio_list pending_bios = BIO_EMPTY_LIST;
 987         bool should_defer;
 988
 989         might_sleep();
 990
 991         if (log_stripe(sh, s) == 0)
 992                 return;
 993
 994         should_defer = conf->batch_bio_dispatch && conf->group_cnt;
 995
 996         for (i = disks; i--; ) {
 997                 int op, op_flags = 0;
 998                 int replace_only = 0;
 999                 struct bio *bi, *rbi;
1000                 struct md_rdev *rdev, *rrdev = NULL;
1001
1002                 sh = head_sh;
1003                 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
1004                         op = REQ_OP_WRITE;
1005                         if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
1006                                 op_flags = REQ_FUA;
1007                         if (test_bit(R5_Discard, &sh->dev[i].flags))
1008                                 op = REQ_OP_DISCARD;
1009                 } else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1010                         op = REQ_OP_READ;
1011                 else if (test_and_clear_bit(R5_WantReplace,
1012                                             &sh->dev[i].flags)) {
1013                         op = REQ_OP_WRITE;
1014                         replace_only = 1;
1015                 } else
1016                         continue;
1017                 if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
1018                         op_flags |= REQ_SYNC;
1019
1020 again:
1021                 bi = &sh->dev[i].req;
1022                 rbi = &sh->dev[i].rreq; /* For writing to replacement */
1023
1024                 rcu_read_lock();
1025                 rrdev = rcu_dereference(conf->disks[i].replacement);
1026                 smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
1027                 rdev = rcu_dereference(conf->disks[i].rdev);
1028                 if (!rdev) {
1029                         rdev = rrdev;
1030                         rrdev = NULL;
1031                 }
1032                 if (op_is_write(op)) {
1033                         if (replace_only)
1034                                 rdev = NULL;
1035                         if (rdev == rrdev)
1036                                 /* We raced and saw duplicates */
1037                                 rrdev = NULL;
1038                 } else {
1039                         if (test_bit(R5_ReadRepl, &head_sh->dev[i].flags) && rrdev)
1040                                 rdev = rrdev;
1041                         rrdev = NULL;
1042                 }
1043
1044                 if (rdev && test_bit(Faulty, &rdev->flags))
1045                         rdev = NULL;
1046                 if (rdev)
1047                         atomic_inc(&rdev->nr_pending);
1048                 if (rrdev && test_bit(Faulty, &rrdev->flags))
1049                         rrdev = NULL;
1050                 if (rrdev)
1051                         atomic_inc(&rrdev->nr_pending);
1052                 rcu_read_unlock();
1053
1054                 /* We have already checked bad blocks for reads.  Now
1055                  * need to check for writes.  We never accept write errors
1056                  * on the replacement, so we don't to check rrdev.
1057                  */
1058                 while (op_is_write(op) && rdev &&
1059                        test_bit(WriteErrorSeen, &rdev->flags)) {
1060                         sector_t first_bad;
1061                         int bad_sectors;
1062                         int bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
1063                                               &first_bad, &bad_sectors);
1064                         if (!bad)
1065                                 break;
1066
1067                         if (bad < 0) {
1068                                 set_bit(BlockedBadBlocks, &rdev->flags);
1069                                 if (!conf->mddev->external &&
1070                                     conf->mddev->sb_flags) {
1071                                         /* It is very unlikely, but we might
1072                                          * still need to write out the
1073                                          * bad block log - better give it
1074                                          * a chance*/
1075                                         md_check_recovery(conf->mddev);
1076                                 }
1077                                 /*
1078                                  * Because md_wait_for_blocked_rdev
1079                                  * will dec nr_pending, we must
1080                                  * increment it first.
1081                                  */
1082                                 atomic_inc(&rdev->nr_pending);
1083                                 md_wait_for_blocked_rdev(rdev, conf->mddev);
1084                         } else {
1085                                 /* Acknowledged bad block - skip the write */
1086                                 rdev_dec_pending(rdev, conf->mddev);
1087                                 rdev = NULL;
1088                         }
1089                 }
1090
1091                 if (rdev) {
1092                         if (s->syncing || s->expanding || s->expanded
1093                             || s->replacing)
1094                                 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
1095
1096                         set_bit(STRIPE_IO_STARTED, &sh->state);
1097
1098                         bi->bi_bdev = rdev->bdev;
1099                         bio_set_op_attrs(bi, op, op_flags);
1100                         bi->bi_end_io = op_is_write(op)
1101                                 ? raid5_end_write_request
1102                                 : raid5_end_read_request;
1103                         bi->bi_private = sh;
1104
1105                         pr_debug("%s: for %llu schedule op %d on disc %d\n",
1106                                 __func__, (unsigned long long)sh->sector,
1107                                 bi->bi_opf, i);
1108                         atomic_inc(&sh->count);
1109                         if (sh != head_sh)
1110                                 atomic_inc(&head_sh->count);
1111                         if (use_new_offset(conf, sh))
1112                                 bi->bi_iter.bi_sector = (sh->sector
1113                                                  + rdev->new_data_offset);
1114                         else
1115                                 bi->bi_iter.bi_sector = (sh->sector
1116                                                  + rdev->data_offset);
1117                         if (test_bit(R5_ReadNoMerge, &head_sh->dev[i].flags))
1118                                 bi->bi_opf |= REQ_NOMERGE;
1119
1120                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1121                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1122
1123                         if (!op_is_write(op) &&
1124                             test_bit(R5_InJournal, &sh->dev[i].flags))
1125                                 /*
1126                                  * issuing read for a page in journal, this
1127                                  * must be preparing for prexor in rmw; read
1128                                  * the data into orig_page
1129                                  */
1130                                 sh->dev[i].vec.bv_page = sh->dev[i].orig_page;
1131                         else
1132                                 sh->dev[i].vec.bv_page = sh->dev[i].page;
1133                         bi->bi_vcnt = 1;
1134                         bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1135                         bi->bi_io_vec[0].bv_offset = 0;
1136                         bi->bi_iter.bi_size = STRIPE_SIZE;
1137                         /*
1138                          * If this is discard request, set bi_vcnt 0. We don't
1139                          * want to confuse SCSI because SCSI will replace payload
1140                          */
1141                         if (op == REQ_OP_DISCARD)
1142                                 bi->bi_vcnt = 0;
1143                         if (rrdev)
1144                                 set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
1145
1146                         if (conf->mddev->gendisk)
1147                                 trace_block_bio_remap(bdev_get_queue(bi->bi_bdev),
1148                                                       bi, disk_devt(conf->mddev->gendisk),
1149                                                       sh->dev[i].sector);
1150                         if (should_defer && op_is_write(op))
1151                                 bio_list_add(&pending_bios, bi);
1152                         else
1153                                 generic_make_request(bi);
1154                 }
1155                 if (rrdev) {
1156                         if (s->syncing || s->expanding || s->expanded
1157                             || s->replacing)
1158                                 md_sync_acct(rrdev->bdev, STRIPE_SECTORS);
1159
1160                         set_bit(STRIPE_IO_STARTED, &sh->state);
1161
1162                         rbi->bi_bdev = rrdev->bdev;
1163                         bio_set_op_attrs(rbi, op, op_flags);
1164                         BUG_ON(!op_is_write(op));
1165                         rbi->bi_end_io = raid5_end_write_request;
1166                         rbi->bi_private = sh;
1167
1168                         pr_debug("%s: for %llu schedule op %d on "
1169                                  "replacement disc %d\n",
1170                                 __func__, (unsigned long long)sh->sector,
1171                                 rbi->bi_opf, i);
1172                         atomic_inc(&sh->count);
1173                         if (sh != head_sh)
1174                                 atomic_inc(&head_sh->count);
1175                         if (use_new_offset(conf, sh))
1176                                 rbi->bi_iter.bi_sector = (sh->sector
1177                                                   + rrdev->new_data_offset);
1178                         else
1179                                 rbi->bi_iter.bi_sector = (sh->sector
1180                                                   + rrdev->data_offset);
1181                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1182                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1183                         sh->dev[i].rvec.bv_page = sh->dev[i].page;
1184                         rbi->bi_vcnt = 1;
1185                         rbi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1186                         rbi->bi_io_vec[0].bv_offset = 0;
1187                         rbi->bi_iter.bi_size = STRIPE_SIZE;
1188                         /*
1189                          * If this is discard request, set bi_vcnt 0. We don't
1190                          * want to confuse SCSI because SCSI will replace payload
1191                          */
1192                         if (op == REQ_OP_DISCARD)
1193                                 rbi->bi_vcnt = 0;
1194                         if (conf->mddev->gendisk)
1195                                 trace_block_bio_remap(bdev_get_queue(rbi->bi_bdev),
1196                                                       rbi, disk_devt(conf->mddev->gendisk),
1197                                                       sh->dev[i].sector);
1198                         if (should_defer && op_is_write(op))
1199                                 bio_list_add(&pending_bios, rbi);
1200                         else
1201                                 generic_make_request(rbi);
1202                 }
1203                 if (!rdev && !rrdev) {
1204                         if (op_is_write(op))
1205                                 set_bit(STRIPE_DEGRADED, &sh->state);
1206                         pr_debug("skip op %d on disc %d for sector %llu\n",
1207                                 bi->bi_opf, i, (unsigned long long)sh->sector);
1208                         clear_bit(R5_LOCKED, &sh->dev[i].flags);
1209                         set_bit(STRIPE_HANDLE, &sh->state);
1210                 }
1211
1212                 if (!head_sh->batch_head)
1213                         continue;
1214                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1215                                       batch_list);
1216                 if (sh != head_sh)
1217                         goto again;
1218         }
1219
1220         if (should_defer && !bio_list_empty(&pending_bios))
1221                 defer_issue_bios(conf, head_sh->sector, &pending_bios);
1222 }
1223
1224 static struct dma_async_tx_descriptor *
1225 async_copy_data(int frombio, struct bio *bio, struct page **page,
1226         sector_t sector, struct dma_async_tx_descriptor *tx,
1227         struct stripe_head *sh, int no_skipcopy)
1228 {
1229         struct bio_vec bvl;
1230         struct bvec_iter iter;
1231         struct page *bio_page;
1232         int page_offset;
1233         struct async_submit_ctl submit;
1234         enum async_tx_flags flags = 0;
1235
1236         if (bio->bi_iter.bi_sector >= sector)
1237                 page_offset = (signed)(bio->bi_iter.bi_sector - sector) * 512;
1238         else
1239                 page_offset = (signed)(sector - bio->bi_iter.bi_sector) * -512;
1240
1241         if (frombio)
1242                 flags |= ASYNC_TX_FENCE;
1243         init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
1244
1245         bio_for_each_segment(bvl, bio, iter) {
1246                 int len = bvl.bv_len;
1247                 int clen;
1248                 int b_offset = 0;
1249
1250                 if (page_offset < 0) {
1251                         b_offset = -page_offset;
1252                         page_offset += b_offset;
1253                         len -= b_offset;
1254                 }
1255
1256                 if (len > 0 && page_offset + len > STRIPE_SIZE)
1257                         clen = STRIPE_SIZE - page_offset;
1258                 else
1259                         clen = len;
1260
1261                 if (clen > 0) {
1262                         b_offset += bvl.bv_offset;
1263                         bio_page = bvl.bv_page;
1264                         if (frombio) {
1265                                 if (sh->raid_conf->skip_copy &&
1266                                     b_offset == 0 && page_offset == 0 &&
1267                                     clen == STRIPE_SIZE &&
1268                                     !no_skipcopy)
1269                                         *page = bio_page;
1270                                 else
1271                                         tx = async_memcpy(*page, bio_page, page_offset,
1272                                                   b_offset, clen, &submit);
1273                         } else
1274                                 tx = async_memcpy(bio_page, *page, b_offset,
1275                                                   page_offset, clen, &submit);
1276                 }
1277                 /* chain the operations */
1278                 submit.depend_tx = tx;
1279
1280                 if (clen < len) /* hit end of page */
1281                         break;
1282                 page_offset +=  len;
1283         }
1284
1285         return tx;
1286 }
1287
1288 static void ops_complete_biofill(void *stripe_head_ref)
1289 {
1290         struct stripe_head *sh = stripe_head_ref;
1291         int i;
1292
1293         pr_debug("%s: stripe %llu\n", __func__,
1294                 (unsigned long long)sh->sector);
1295
1296         /* clear completed biofills */
1297         for (i = sh->disks; i--; ) {
1298                 struct r5dev *dev = &sh->dev[i];
1299
1300                 /* acknowledge completion of a biofill operation */
1301                 /* and check if we need to reply to a read request,
1302                  * new R5_Wantfill requests are held off until
1303                  * !STRIPE_BIOFILL_RUN
1304                  */
1305                 if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
1306                         struct bio *rbi, *rbi2;
1307
1308                         BUG_ON(!dev->read);
1309                         rbi = dev->read;
1310                         dev->read = NULL;
1311                         while (rbi && rbi->bi_iter.bi_sector <
1312                                 dev->sector + STRIPE_SECTORS) {
1313                                 rbi2 = r5_next_bio(rbi, dev->sector);
1314                                 bio_endio(rbi);
1315                                 rbi = rbi2;
1316                         }
1317                 }
1318         }
1319         clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
1320
1321         set_bit(STRIPE_HANDLE, &sh->state);
1322         raid5_release_stripe(sh);
1323 }
1324
1325 static void ops_run_biofill(struct stripe_head *sh)
1326 {
1327         struct dma_async_tx_descriptor *tx = NULL;
1328         struct async_submit_ctl submit;
1329         int i;
1330
1331         BUG_ON(sh->batch_head);
1332         pr_debug("%s: stripe %llu\n", __func__,
1333                 (unsigned long long)sh->sector);
1334
1335         for (i = sh->disks; i--; ) {
1336                 struct r5dev *dev = &sh->dev[i];
1337                 if (test_bit(R5_Wantfill, &dev->flags)) {
1338                         struct bio *rbi;
1339                         spin_lock_irq(&sh->stripe_lock);
1340                         dev->read = rbi = dev->toread;
1341                         dev->toread = NULL;
1342                         spin_unlock_irq(&sh->stripe_lock);
1343                         while (rbi && rbi->bi_iter.bi_sector <
1344                                 dev->sector + STRIPE_SECTORS) {
1345                                 tx = async_copy_data(0, rbi, &dev->page,
1346                                                      dev->sector, tx, sh, 0);
1347                                 rbi = r5_next_bio(rbi, dev->sector);
1348                         }
1349                 }
1350         }
1351
1352         atomic_inc(&sh->count);
1353         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
1354         async_trigger_callback(&submit);
1355 }
1356
1357 static void mark_target_uptodate(struct stripe_head *sh, int target)
1358 {
1359         struct r5dev *tgt;
1360
1361         if (target < 0)
1362                 return;
1363
1364         tgt = &sh->dev[target];
1365         set_bit(R5_UPTODATE, &tgt->flags);
1366         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1367         clear_bit(R5_Wantcompute, &tgt->flags);
1368 }
1369
1370 static void ops_complete_compute(void *stripe_head_ref)
1371 {
1372         struct stripe_head *sh = stripe_head_ref;
1373
1374         pr_debug("%s: stripe %llu\n", __func__,
1375                 (unsigned long long)sh->sector);
1376
1377         /* mark the computed target(s) as uptodate */
1378         mark_target_uptodate(sh, sh->ops.target);
1379         mark_target_uptodate(sh, sh->ops.target2);
1380
1381         clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
1382         if (sh->check_state == check_state_compute_run)
1383                 sh->check_state = check_state_compute_result;
1384         set_bit(STRIPE_HANDLE, &sh->state);
1385         raid5_release_stripe(sh);
1386 }
1387
1388 /* return a pointer to the address conversion region of the scribble buffer */
1389 static addr_conv_t *to_addr_conv(struct stripe_head *sh,
1390                                  struct raid5_percpu *percpu, int i)
1391 {
1392         void *addr;
1393
1394         addr = flex_array_get(percpu->scribble, i);
1395         return addr + sizeof(struct page *) * (sh->disks + 2);
1396 }
1397
1398 /* return a pointer to the address conversion region of the scribble buffer */
1399 static struct page **to_addr_page(struct raid5_percpu *percpu, int i)
1400 {
1401         void *addr;
1402
1403         addr = flex_array_get(percpu->scribble, i);
1404         return addr;
1405 }
1406
1407 static struct dma_async_tx_descriptor *
1408 ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
1409 {
1410         int disks = sh->disks;
1411         struct page **xor_srcs = to_addr_page(percpu, 0);
1412         int target = sh->ops.target;
1413         struct r5dev *tgt = &sh->dev[target];
1414         struct page *xor_dest = tgt->page;
1415         int count = 0;
1416         struct dma_async_tx_descriptor *tx;
1417         struct async_submit_ctl submit;
1418         int i;
1419
1420         BUG_ON(sh->batch_head);
1421
1422         pr_debug("%s: stripe %llu block: %d\n",
1423                 __func__, (unsigned long long)sh->sector, target);
1424         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1425
1426         for (i = disks; i--; )
1427                 if (i != target)
1428                         xor_srcs[count++] = sh->dev[i].page;
1429
1430         atomic_inc(&sh->count);
1431
1432         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
1433                           ops_complete_compute, sh, to_addr_conv(sh, percpu, 0));
1434         if (unlikely(count == 1))
1435                 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
1436         else
1437                 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1438
1439         return tx;
1440 }
1441
1442 /* set_syndrome_sources - populate source buffers for gen_syndrome
1443  * @srcs - (struct page *) array of size sh->disks
1444  * @sh - stripe_head to parse
1445  *
1446  * Populates srcs in proper layout order for the stripe and returns the
1447  * 'count' of sources to be used in a call to async_gen_syndrome.  The P
1448  * destination buffer is recorded in srcs[count] and the Q destination
1449  * is recorded in srcs[count+1]].
1450  */
1451 static int set_syndrome_sources(struct page **srcs,
1452                                 struct stripe_head *sh,
1453                                 int srctype)
1454 {
1455         int disks = sh->disks;
1456         int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
1457         int d0_idx = raid6_d0(sh);
1458         int count;
1459         int i;
1460
1461         for (i = 0; i < disks; i++)
1462                 srcs[i] = NULL;
1463
1464         count = 0;
1465         i = d0_idx;
1466         do {
1467                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1468                 struct r5dev *dev = &sh->dev[i];
1469
1470                 if (i == sh->qd_idx || i == sh->pd_idx ||
1471                     (srctype == SYNDROME_SRC_ALL) ||
1472                     (srctype == SYNDROME_SRC_WANT_DRAIN &&
1473                      (test_bit(R5_Wantdrain, &dev->flags) ||
1474                       test_bit(R5_InJournal, &dev->flags))) ||
1475                     (srctype == SYNDROME_SRC_WRITTEN &&
1476                      (dev->written ||
1477                       test_bit(R5_InJournal, &dev->flags)))) {
1478                         if (test_bit(R5_InJournal, &dev->flags))
1479                                 srcs[slot] = sh->dev[i].orig_page;
1480                         else
1481                                 srcs[slot] = sh->dev[i].page;
1482                 }
1483                 i = raid6_next_disk(i, disks);
1484         } while (i != d0_idx);
1485
1486         return syndrome_disks;
1487 }
1488
1489 static struct dma_async_tx_descriptor *
1490 ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
1491 {
1492         int disks = sh->disks;
1493         struct page **blocks = to_addr_page(percpu, 0);
1494         int target;
1495         int qd_idx = sh->qd_idx;
1496         struct dma_async_tx_descriptor *tx;
1497         struct async_submit_ctl submit;
1498         struct r5dev *tgt;
1499         struct page *dest;
1500         int i;
1501         int count;
1502
1503         BUG_ON(sh->batch_head);
1504         if (sh->ops.target < 0)
1505                 target = sh->ops.target2;
1506         else if (sh->ops.target2 < 0)
1507                 target = sh->ops.target;
1508         else
1509                 /* we should only have one valid target */
1510                 BUG();
1511         BUG_ON(target < 0);
1512         pr_debug("%s: stripe %llu block: %d\n",
1513                 __func__, (unsigned long long)sh->sector, target);
1514
1515         tgt = &sh->dev[target];
1516         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1517         dest = tgt->page;
1518
1519         atomic_inc(&sh->count);
1520
1521         if (target == qd_idx) {
1522                 count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1523                 blocks[count] = NULL; /* regenerating p is not necessary */
1524                 BUG_ON(blocks[count+1] != dest); /* q should already be set */
1525                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1526                                   ops_complete_compute, sh,
1527                                   to_addr_conv(sh, percpu, 0));
1528                 tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
1529         } else {
1530                 /* Compute any data- or p-drive using XOR */
1531                 count = 0;
1532                 for (i = disks; i-- ; ) {
1533                         if (i == target || i == qd_idx)
1534                                 continue;
1535                         blocks[count++] = sh->dev[i].page;
1536                 }
1537
1538                 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1539                                   NULL, ops_complete_compute, sh,
1540                                   to_addr_conv(sh, percpu, 0));
1541                 tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
1542         }
1543
1544         return tx;
1545 }
1546
1547 static struct dma_async_tx_descriptor *
1548 ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
1549 {
1550         int i, count, disks = sh->disks;
1551         int syndrome_disks = sh->ddf_layout ? disks : disks-2;
1552         int d0_idx = raid6_d0(sh);
1553         int faila = -1, failb = -1;
1554         int target = sh->ops.target;
1555         int target2 = sh->ops.target2;
1556         struct r5dev *tgt = &sh->dev[target];
1557         struct r5dev *tgt2 = &sh->dev[target2];
1558         struct dma_async_tx_descriptor *tx;
1559         struct page **blocks = to_addr_page(percpu, 0);
1560         struct async_submit_ctl submit;
1561
1562         BUG_ON(sh->batch_head);
1563         pr_debug("%s: stripe %llu block1: %d block2: %d\n",
1564                  __func__, (unsigned long long)sh->sector, target, target2);
1565         BUG_ON(target < 0 || target2 < 0);
1566         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1567         BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
1568
1569         /* we need to open-code set_syndrome_sources to handle the
1570          * slot number conversion for 'faila' and 'failb'
1571          */
1572         for (i = 0; i < disks ; i++)
1573                 blocks[i] = NULL;
1574         count = 0;
1575         i = d0_idx;
1576         do {
1577                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1578
1579                 blocks[slot] = sh->dev[i].page;
1580
1581                 if (i == target)
1582                         faila = slot;
1583                 if (i == target2)
1584                         failb = slot;
1585                 i = raid6_next_disk(i, disks);
1586         } while (i != d0_idx);
1587
1588         BUG_ON(faila == failb);
1589         if (failb < faila)
1590                 swap(faila, failb);
1591         pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
1592                  __func__, (unsigned long long)sh->sector, faila, failb);
1593
1594         atomic_inc(&sh->count);
1595
1596         if (failb == syndrome_disks+1) {
1597                 /* Q disk is one of the missing disks */
1598                 if (faila == syndrome_disks) {
1599                         /* Missing P+Q, just recompute */
1600                         init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1601                                           ops_complete_compute, sh,
1602                                           to_addr_conv(sh, percpu, 0));
1603                         return async_gen_syndrome(blocks, 0, syndrome_disks+2,
1604                                                   STRIPE_SIZE, &submit);
1605                 } else {
1606                         struct page *dest;
1607                         int data_target;
1608                         int qd_idx = sh->qd_idx;
1609
1610                         /* Missing D+Q: recompute D from P, then recompute Q */
1611                         if (target == qd_idx)
1612                                 data_target = target2;
1613                         else
1614                                 data_target = target;
1615
1616                         count = 0;
1617                         for (i = disks; i-- ; ) {
1618                                 if (i == data_target || i == qd_idx)
1619                                         continue;
1620                                 blocks[count++] = sh->dev[i].page;
1621                         }
1622                         dest = sh->dev[data_target].page;
1623                         init_async_submit(&submit,
1624                                           ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1625                                           NULL, NULL, NULL,
1626                                           to_addr_conv(sh, percpu, 0));
1627                         tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
1628                                        &submit);
1629
1630                         count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1631                         init_async_submit(&submit, ASYNC_TX_FENCE, tx,
1632                                           ops_complete_compute, sh,
1633                                           to_addr_conv(sh, percpu, 0));
1634                         return async_gen_syndrome(blocks, 0, count+2,
1635                                                   STRIPE_SIZE, &submit);
1636                 }
1637         } else {
1638                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1639                                   ops_complete_compute, sh,
1640                                   to_addr_conv(sh, percpu, 0));
1641                 if (failb == syndrome_disks) {
1642                         /* We're missing D+P. */
1643                         return async_raid6_datap_recov(syndrome_disks+2,
1644                                                        STRIPE_SIZE, faila,
1645                                                        blocks, &submit);
1646                 } else {
1647                         /* We're missing D+D. */
1648                         return async_raid6_2data_recov(syndrome_disks+2,
1649                                                        STRIPE_SIZE, faila, failb,
1650                                                        blocks, &submit);
1651                 }
1652         }
1653 }
1654
1655 static void ops_complete_prexor(void *stripe_head_ref)
1656 {
1657         struct stripe_head *sh = stripe_head_ref;
1658
1659         pr_debug("%s: stripe %llu\n", __func__,
1660                 (unsigned long long)sh->sector);
1661
1662         if (r5c_is_writeback(sh->raid_conf->log))
1663                 /*
1664                  * raid5-cache write back uses orig_page during prexor.
1665                  * After prexor, it is time to free orig_page
1666                  */
1667                 r5c_release_extra_page(sh);
1668 }
1669
1670 static struct dma_async_tx_descriptor *
1671 ops_run_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
1672                 struct dma_async_tx_descriptor *tx)
1673 {
1674         int disks = sh->disks;
1675         struct page **xor_srcs = to_addr_page(percpu, 0);
1676         int count = 0, pd_idx = sh->pd_idx, i;
1677         struct async_submit_ctl submit;
1678
1679         /* existing parity data subtracted */
1680         struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1681
1682         BUG_ON(sh->batch_head);
1683         pr_debug("%s: stripe %llu\n", __func__,
1684                 (unsigned long long)sh->sector);
1685
1686         for (i = disks; i--; ) {
1687                 struct r5dev *dev = &sh->dev[i];
1688                 /* Only process blocks that are known to be uptodate */
1689                 if (test_bit(R5_InJournal, &dev->flags))
1690                         xor_srcs[count++] = dev->orig_page;
1691                 else if (test_bit(R5_Wantdrain, &dev->flags))
1692                         xor_srcs[count++] = dev->page;
1693         }
1694
1695         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1696                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1697         tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1698
1699         return tx;
1700 }
1701
1702 static struct dma_async_tx_descriptor *
1703 ops_run_prexor6(struct stripe_head *sh, struct raid5_percpu *percpu,
1704                 struct dma_async_tx_descriptor *tx)
1705 {
1706         struct page **blocks = to_addr_page(percpu, 0);
1707         int count;
1708         struct async_submit_ctl submit;
1709
1710         pr_debug("%s: stripe %llu\n", __func__,
1711                 (unsigned long long)sh->sector);
1712
1713         count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_WANT_DRAIN);
1714
1715         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_PQ_XOR_DST, tx,
1716                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1717         tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
1718
1719         return tx;
1720 }
1721
1722 static struct dma_async_tx_descriptor *
1723 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1724 {
1725         struct r5conf *conf = sh->raid_conf;
1726         int disks = sh->disks;
1727         int i;
1728         struct stripe_head *head_sh = sh;
1729
1730         pr_debug("%s: stripe %llu\n", __func__,
1731                 (unsigned long long)sh->sector);
1732
1733         for (i = disks; i--; ) {
1734                 struct r5dev *dev;
1735                 struct bio *chosen;
1736
1737                 sh = head_sh;
1738                 if (test_and_clear_bit(R5_Wantdrain, &head_sh->dev[i].flags)) {
1739                         struct bio *wbi;
1740
1741 again:
1742                         dev = &sh->dev[i];
1743                         /*
1744                          * clear R5_InJournal, so when rewriting a page in
1745                          * journal, it is not skipped by r5l_log_stripe()
1746                          */
1747                         clear_bit(R5_InJournal, &dev->flags);
1748                         spin_lock_irq(&sh->stripe_lock);
1749                         chosen = dev->towrite;
1750                         dev->towrite = NULL;
1751                         sh->overwrite_disks = 0;
1752                         BUG_ON(dev->written);
1753                         wbi = dev->written = chosen;
1754                         spin_unlock_irq(&sh->stripe_lock);
1755                         WARN_ON(dev->page != dev->orig_page);
1756
1757                         while (wbi && wbi->bi_iter.bi_sector <
1758                                 dev->sector + STRIPE_SECTORS) {
1759                                 if (wbi->bi_opf & REQ_FUA)
1760                                         set_bit(R5_WantFUA, &dev->flags);
1761                                 if (wbi->bi_opf & REQ_SYNC)
1762                                         set_bit(R5_SyncIO, &dev->flags);
1763                                 if (bio_op(wbi) == REQ_OP_DISCARD)
1764                                         set_bit(R5_Discard, &dev->flags);
1765                                 else {
1766                                         tx = async_copy_data(1, wbi, &dev->page,
1767                                                              dev->sector, tx, sh,
1768                                                              r5c_is_writeback(conf->log));
1769                                         if (dev->page != dev->orig_page &&
1770                                             !r5c_is_writeback(conf->log)) {
1771                                                 set_bit(R5_SkipCopy, &dev->flags);
1772                                                 clear_bit(R5_UPTODATE, &dev->flags);
1773                                                 clear_bit(R5_OVERWRITE, &dev->flags);
1774                                         }
1775                                 }
1776                                 wbi = r5_next_bio(wbi, dev->sector);
1777                         }
1778
1779                         if (head_sh->batch_head) {
1780                                 sh = list_first_entry(&sh->batch_list,
1781                                                       struct stripe_head,
1782                                                       batch_list);
1783                                 if (sh == head_sh)
1784                                         continue;
1785                                 goto again;
1786                         }
1787                 }
1788         }
1789
1790         return tx;
1791 }
1792
1793 static void ops_complete_reconstruct(void *stripe_head_ref)
1794 {
1795         struct stripe_head *sh = stripe_head_ref;
1796         int disks = sh->disks;
1797         int pd_idx = sh->pd_idx;
1798         int qd_idx = sh->qd_idx;
1799         int i;
1800         bool fua = false, sync = false, discard = false;
1801
1802         pr_debug("%s: stripe %llu\n", __func__,
1803                 (unsigned long long)sh->sector);
1804
1805         for (i = disks; i--; ) {
1806                 fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
1807                 sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
1808                 discard |= test_bit(R5_Discard, &sh->dev[i].flags);
1809         }
1810
1811         for (i = disks; i--; ) {
1812                 struct r5dev *dev = &sh->dev[i];
1813
1814                 if (dev->written || i == pd_idx || i == qd_idx) {
1815                         if (!discard && !test_bit(R5_SkipCopy, &dev->flags))
1816                                 set_bit(R5_UPTODATE, &dev->flags);
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         int devs = max(conf->raid_disks, conf->previous_raid_disks);
2192
2193         if (conf->mddev->gendisk)
2194                 sprintf(conf->cache_name[0],
2195                         "raid%d-%s", conf->level, mdname(conf->mddev));
2196         else
2197                 sprintf(conf->cache_name[0],
2198                         "raid%d-%p", conf->level, conf->mddev);
2199         sprintf(conf->cache_name[1], "%s-alt", conf->cache_name[0]);
2200
2201         conf->active_name = 0;
2202         sc = kmem_cache_create(conf->cache_name[conf->active_name],
2203                                sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
2204                                0, 0, NULL);
2205         if (!sc)
2206                 return 1;
2207         conf->slab_cache = sc;
2208         conf->pool_size = devs;
2209         while (num--)
2210                 if (!grow_one_stripe(conf, GFP_KERNEL))
2211                         return 1;
2212
2213         return 0;
2214 }
2215
2216 /**
2217  * scribble_len - return the required size of the scribble region
2218  * @num - total number of disks in the array
2219  *
2220  * The size must be enough to contain:
2221  * 1/ a struct page pointer for each device in the array +2
2222  * 2/ room to convert each entry in (1) to its corresponding dma
2223  *    (dma_map_page()) or page (page_address()) address.
2224  *
2225  * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
2226  * calculate over all devices (not just the data blocks), using zeros in place
2227  * of the P and Q blocks.
2228  */
2229 static struct flex_array *scribble_alloc(int num, int cnt, gfp_t flags)
2230 {
2231         struct flex_array *ret;
2232         size_t len;
2233
2234         len = sizeof(struct page *) * (num+2) + sizeof(addr_conv_t) * (num+2);
2235         ret = flex_array_alloc(len, cnt, flags);
2236         if (!ret)
2237                 return NULL;
2238         /* always prealloc all elements, so no locking is required */
2239         if (flex_array_prealloc(ret, 0, cnt, flags)) {
2240                 flex_array_free(ret);
2241                 return NULL;
2242         }
2243         return ret;
2244 }
2245
2246 static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
2247 {
2248         unsigned long cpu;
2249         int err = 0;
2250
2251         /*
2252          * Never shrink. And mddev_suspend() could deadlock if this is called
2253          * from raid5d. In that case, scribble_disks and scribble_sectors
2254          * should equal to new_disks and new_sectors
2255          */
2256         if (conf->scribble_disks >= new_disks &&
2257             conf->scribble_sectors >= new_sectors)
2258                 return 0;
2259         mddev_suspend(conf->mddev);
2260         get_online_cpus();
2261         for_each_present_cpu(cpu) {
2262                 struct raid5_percpu *percpu;
2263                 struct flex_array *scribble;
2264
2265                 percpu = per_cpu_ptr(conf->percpu, cpu);
2266                 scribble = scribble_alloc(new_disks,
2267                                           new_sectors / STRIPE_SECTORS,
2268                                           GFP_NOIO);
2269
2270                 if (scribble) {
2271                         flex_array_free(percpu->scribble);
2272                         percpu->scribble = scribble;
2273                 } else {
2274                         err = -ENOMEM;
2275                         break;
2276                 }
2277         }
2278         put_online_cpus();
2279         mddev_resume(conf->mddev);
2280         if (!err) {
2281                 conf->scribble_disks = new_disks;
2282                 conf->scribble_sectors = new_sectors;
2283         }
2284         return err;
2285 }
2286
2287 static int resize_stripes(struct r5conf *conf, int newsize)
2288 {
2289         /* Make all the stripes able to hold 'newsize' devices.
2290          * New slots in each stripe get 'page' set to a new page.
2291          *
2292          * This happens in stages:
2293          * 1/ create a new kmem_cache and allocate the required number of
2294          *    stripe_heads.
2295          * 2/ gather all the old stripe_heads and transfer the pages across
2296          *    to the new stripe_heads.  This will have the side effect of
2297          *    freezing the array as once all stripe_heads have been collected,
2298          *    no IO will be possible.  Old stripe heads are freed once their
2299          *    pages have been transferred over, and the old kmem_cache is
2300          *    freed when all stripes are done.
2301          * 3/ reallocate conf->disks to be suitable bigger.  If this fails,
2302          *    we simple return a failure status - no need to clean anything up.
2303          * 4/ allocate new pages for the new slots in the new stripe_heads.
2304          *    If this fails, we don't bother trying the shrink the
2305          *    stripe_heads down again, we just leave them as they are.
2306          *    As each stripe_head is processed the new one is released into
2307          *    active service.
2308          *
2309          * Once step2 is started, we cannot afford to wait for a write,
2310          * so we use GFP_NOIO allocations.
2311          */
2312         struct stripe_head *osh, *nsh;
2313         LIST_HEAD(newstripes);
2314         struct disk_info *ndisks;
2315         int err;
2316         struct kmem_cache *sc;
2317         int i;
2318         int hash, cnt;
2319
2320         err = md_allow_write(conf->mddev);
2321         if (err)
2322                 return err;
2323
2324         /* Step 1 */
2325         sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
2326                                sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
2327                                0, 0, NULL);
2328         if (!sc)
2329                 return -ENOMEM;
2330
2331         /* Need to ensure auto-resizing doesn't interfere */
2332         mutex_lock(&conf->cache_size_mutex);
2333
2334         for (i = conf->max_nr_stripes; i; i--) {
2335                 nsh = alloc_stripe(sc, GFP_KERNEL, newsize, conf);
2336                 if (!nsh)
2337                         break;
2338
2339                 list_add(&nsh->lru, &newstripes);
2340         }
2341         if (i) {
2342                 /* didn't get enough, give up */
2343                 while (!list_empty(&newstripes)) {
2344                         nsh = list_entry(newstripes.next, struct stripe_head, lru);
2345                         list_del(&nsh->lru);
2346                         free_stripe(sc, nsh);
2347                 }
2348                 kmem_cache_destroy(sc);
2349                 mutex_unlock(&conf->cache_size_mutex);
2350                 return -ENOMEM;
2351         }
2352         /* Step 2 - Must use GFP_NOIO now.
2353          * OK, we have enough stripes, start collecting inactive
2354          * stripes and copying them over
2355          */
2356         hash = 0;
2357         cnt = 0;
2358         list_for_each_entry(nsh, &newstripes, lru) {
2359                 lock_device_hash_lock(conf, hash);
2360                 wait_event_cmd(conf->wait_for_stripe,
2361                                     !list_empty(conf->inactive_list + hash),
2362                                     unlock_device_hash_lock(conf, hash),
2363                                     lock_device_hash_lock(conf, hash));
2364                 osh = get_free_stripe(conf, hash);
2365                 unlock_device_hash_lock(conf, hash);
2366
2367                 for(i=0; i<conf->pool_size; i++) {
2368                         nsh->dev[i].page = osh->dev[i].page;
2369                         nsh->dev[i].orig_page = osh->dev[i].page;
2370                 }
2371                 nsh->hash_lock_index = hash;
2372                 free_stripe(conf->slab_cache, osh);
2373                 cnt++;
2374                 if (cnt >= conf->max_nr_stripes / NR_STRIPE_HASH_LOCKS +
2375                     !!((conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS) > hash)) {
2376                         hash++;
2377                         cnt = 0;
2378                 }
2379         }
2380         kmem_cache_destroy(conf->slab_cache);
2381
2382         /* Step 3.
2383          * At this point, we are holding all the stripes so the array
2384          * is completely stalled, so now is a good time to resize
2385          * conf->disks and the scribble region
2386          */
2387         ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO);
2388         if (ndisks) {
2389                 for (i = 0; i < conf->pool_size; i++)
2390                         ndisks[i] = conf->disks[i];
2391
2392                 for (i = conf->pool_size; i < newsize; i++) {
2393                         ndisks[i].extra_page = alloc_page(GFP_NOIO);
2394                         if (!ndisks[i].extra_page)
2395                                 err = -ENOMEM;
2396                 }
2397
2398                 if (err) {
2399                         for (i = conf->pool_size; i < newsize; i++)
2400                                 if (ndisks[i].extra_page)
2401                                         put_page(ndisks[i].extra_page);
2402                         kfree(ndisks);
2403                 } else {
2404                         kfree(conf->disks);
2405                         conf->disks = ndisks;
2406                 }
2407         } else
2408                 err = -ENOMEM;
2409
2410         mutex_unlock(&conf->cache_size_mutex);
2411
2412         conf->slab_cache = sc;
2413         conf->active_name = 1-conf->active_name;
2414
2415         /* Step 4, return new stripes to service */
2416         while(!list_empty(&newstripes)) {
2417                 nsh = list_entry(newstripes.next, struct stripe_head, lru);
2418                 list_del_init(&nsh->lru);
2419
2420                 for (i=conf->raid_disks; i < newsize; i++)
2421                         if (nsh->dev[i].page == NULL) {
2422                                 struct page *p = alloc_page(GFP_NOIO);
2423                                 nsh->dev[i].page = p;
2424                                 nsh->dev[i].orig_page = p;
2425                                 if (!p)
2426                                         err = -ENOMEM;
2427                         }
2428                 raid5_release_stripe(nsh);
2429         }
2430         /* critical section pass, GFP_NOIO no longer needed */
2431
2432         if (!err)
2433                 conf->pool_size = newsize;
2434         return err;
2435 }
2436
2437 static int drop_one_stripe(struct r5conf *conf)
2438 {
2439         struct stripe_head *sh;
2440         int hash = (conf->max_nr_stripes - 1) & STRIPE_HASH_LOCKS_MASK;
2441
2442         spin_lock_irq(conf->hash_locks + hash);
2443         sh = get_free_stripe(conf, hash);
2444         spin_unlock_irq(conf->hash_locks + hash);
2445         if (!sh)
2446                 return 0;
2447         BUG_ON(atomic_read(&sh->count));
2448         shrink_buffers(sh);
2449         free_stripe(conf->slab_cache, sh);
2450         atomic_dec(&conf->active_stripes);
2451         conf->max_nr_stripes--;
2452         return 1;
2453 }
2454
2455 static void shrink_stripes(struct r5conf *conf)
2456 {
2457         while (conf->max_nr_stripes &&
2458                drop_one_stripe(conf))
2459                 ;
2460
2461         kmem_cache_destroy(conf->slab_cache);
2462         conf->slab_cache = NULL;
2463 }
2464
2465 static void raid5_end_read_request(struct bio * bi)
2466 {
2467         struct stripe_head *sh = bi->bi_private;
2468         struct r5conf *conf = sh->raid_conf;
2469         int disks = sh->disks, i;
2470         char b[BDEVNAME_SIZE];
2471         struct md_rdev *rdev = NULL;
2472         sector_t s;
2473
2474         for (i=0 ; i<disks; i++)
2475                 if (bi == &sh->dev[i].req)
2476                         break;
2477
2478         pr_debug("end_read_request %llu/%d, count: %d, error %d.\n",
2479                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2480                 bi->bi_error);
2481         if (i == disks) {
2482                 bio_reset(bi);
2483                 BUG();
2484                 return;
2485         }
2486         if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2487                 /* If replacement finished while this request was outstanding,
2488                  * 'replacement' might be NULL already.
2489                  * In that case it moved down to 'rdev'.
2490                  * rdev is not removed until all requests are finished.
2491                  */
2492                 rdev = conf->disks[i].replacement;
2493         if (!rdev)
2494                 rdev = conf->disks[i].rdev;
2495
2496         if (use_new_offset(conf, sh))
2497                 s = sh->sector + rdev->new_data_offset;
2498         else
2499                 s = sh->sector + rdev->data_offset;
2500         if (!bi->bi_error) {
2501                 set_bit(R5_UPTODATE, &sh->dev[i].flags);
2502                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2503                         /* Note that this cannot happen on a
2504                          * replacement device.  We just fail those on
2505                          * any error
2506                          */
2507                         pr_info_ratelimited(
2508                                 "md/raid:%s: read error corrected (%lu sectors at %llu on %s)\n",
2509                                 mdname(conf->mddev), STRIPE_SECTORS,
2510                                 (unsigned long long)s,
2511                                 bdevname(rdev->bdev, b));
2512                         atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
2513                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2514                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2515                 } else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2516                         clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2517
2518                 if (test_bit(R5_InJournal, &sh->dev[i].flags))
2519                         /*
2520                          * end read for a page in journal, this
2521                          * must be preparing for prexor in rmw
2522                          */
2523                         set_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags);
2524
2525                 if (atomic_read(&rdev->read_errors))
2526                         atomic_set(&rdev->read_errors, 0);
2527         } else {
2528                 const char *bdn = bdevname(rdev->bdev, b);
2529                 int retry = 0;
2530                 int set_bad = 0;
2531
2532                 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
2533                 atomic_inc(&rdev->read_errors);
2534                 if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2535                         pr_warn_ratelimited(
2536                                 "md/raid:%s: read error on replacement device (sector %llu on %s).\n",
2537                                 mdname(conf->mddev),
2538                                 (unsigned long long)s,
2539                                 bdn);
2540                 else if (conf->mddev->degraded >= conf->max_degraded) {
2541                         set_bad = 1;
2542                         pr_warn_ratelimited(
2543                                 "md/raid:%s: read error not correctable (sector %llu on %s).\n",
2544                                 mdname(conf->mddev),
2545                                 (unsigned long long)s,
2546                                 bdn);
2547                 } else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
2548                         /* Oh, no!!! */
2549                         set_bad = 1;
2550                         pr_warn_ratelimited(
2551                                 "md/raid:%s: read error NOT corrected!! (sector %llu on %s).\n",
2552                                 mdname(conf->mddev),
2553                                 (unsigned long long)s,
2554                                 bdn);
2555                 } else if (atomic_read(&rdev->read_errors)
2556                          > conf->max_nr_stripes)
2557                         pr_warn("md/raid:%s: Too many read errors, failing device %s.\n",
2558                                mdname(conf->mddev), bdn);
2559                 else
2560                         retry = 1;
2561                 if (set_bad && test_bit(In_sync, &rdev->flags)
2562                     && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2563                         retry = 1;
2564                 if (retry)
2565                         if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
2566                                 set_bit(R5_ReadError, &sh->dev[i].flags);
2567                                 clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2568                         } else
2569                                 set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2570                 else {
2571                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2572                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2573                         if (!(set_bad
2574                               && test_bit(In_sync, &rdev->flags)
2575                               && rdev_set_badblocks(
2576                                       rdev, sh->sector, STRIPE_SECTORS, 0)))
2577                                 md_error(conf->mddev, rdev);
2578                 }
2579         }
2580         rdev_dec_pending(rdev, conf->mddev);
2581         bio_reset(bi);
2582         clear_bit(R5_LOCKED, &sh->dev[i].flags);
2583         set_bit(STRIPE_HANDLE, &sh->state);
2584         raid5_release_stripe(sh);
2585 }
2586
2587 static void raid5_end_write_request(struct bio *bi)
2588 {
2589         struct stripe_head *sh = bi->bi_private;
2590         struct r5conf *conf = sh->raid_conf;
2591         int disks = sh->disks, i;
2592         struct md_rdev *uninitialized_var(rdev);
2593         sector_t first_bad;
2594         int bad_sectors;
2595         int replacement = 0;
2596
2597         for (i = 0 ; i < disks; i++) {
2598                 if (bi == &sh->dev[i].req) {
2599                         rdev = conf->disks[i].rdev;
2600                         break;
2601                 }
2602                 if (bi == &sh->dev[i].rreq) {
2603                         rdev = conf->disks[i].replacement;
2604                         if (rdev)
2605                                 replacement = 1;
2606                         else
2607                                 /* rdev was removed and 'replacement'
2608                                  * replaced it.  rdev is not removed
2609                                  * until all requests are finished.
2610                                  */
2611                                 rdev = conf->disks[i].rdev;
2612                         break;
2613                 }
2614         }
2615         pr_debug("end_write_request %llu/%d, count %d, error: %d.\n",
2616                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2617                 bi->bi_error);
2618         if (i == disks) {
2619                 bio_reset(bi);
2620                 BUG();
2621                 return;
2622         }
2623
2624         if (replacement) {
2625                 if (bi->bi_error)
2626                         md_error(conf->mddev, rdev);
2627                 else if (is_badblock(rdev, sh->sector,
2628                                      STRIPE_SECTORS,
2629                                      &first_bad, &bad_sectors))
2630                         set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
2631         } else {
2632                 if (bi->bi_error) {
2633                         set_bit(STRIPE_DEGRADED, &sh->state);
2634                         set_bit(WriteErrorSeen, &rdev->flags);
2635                         set_bit(R5_WriteError, &sh->dev[i].flags);
2636                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
2637                                 set_bit(MD_RECOVERY_NEEDED,
2638                                         &rdev->mddev->recovery);
2639                 } else if (is_badblock(rdev, sh->sector,
2640                                        STRIPE_SECTORS,
2641                                        &first_bad, &bad_sectors)) {
2642                         set_bit(R5_MadeGood, &sh->dev[i].flags);
2643                         if (test_bit(R5_ReadError, &sh->dev[i].flags))
2644                                 /* That was a successful write so make
2645                                  * sure it looks like we already did
2646                                  * a re-write.
2647                                  */
2648                                 set_bit(R5_ReWrite, &sh->dev[i].flags);
2649                 }
2650         }
2651         rdev_dec_pending(rdev, conf->mddev);
2652
2653         if (sh->batch_head && bi->bi_error && !replacement)
2654                 set_bit(STRIPE_BATCH_ERR, &sh->batch_head->state);
2655
2656         bio_reset(bi);
2657         if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
2658                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
2659         set_bit(STRIPE_HANDLE, &sh->state);
2660         raid5_release_stripe(sh);
2661
2662         if (sh->batch_head && sh != sh->batch_head)
2663                 raid5_release_stripe(sh->batch_head);
2664 }
2665
2666 static void raid5_build_block(struct stripe_head *sh, int i, int previous)
2667 {
2668         struct r5dev *dev = &sh->dev[i];
2669
2670         dev->flags = 0;
2671         dev->sector = raid5_compute_blocknr(sh, i, previous);
2672 }
2673
2674 static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
2675 {
2676         char b[BDEVNAME_SIZE];
2677         struct r5conf *conf = mddev->private;
2678         unsigned long flags;
2679         pr_debug("raid456: error called\n");
2680
2681         spin_lock_irqsave(&conf->device_lock, flags);
2682         clear_bit(In_sync, &rdev->flags);
2683         mddev->degraded = raid5_calc_degraded(conf);
2684         spin_unlock_irqrestore(&conf->device_lock, flags);
2685         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2686
2687         set_bit(Blocked, &rdev->flags);
2688         set_bit(Faulty, &rdev->flags);
2689         set_mask_bits(&mddev->sb_flags, 0,
2690                       BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
2691         pr_crit("md/raid:%s: Disk failure on %s, disabling device.\n"
2692                 "md/raid:%s: Operation continuing on %d devices.\n",
2693                 mdname(mddev),
2694                 bdevname(rdev->bdev, b),
2695                 mdname(mddev),
2696                 conf->raid_disks - mddev->degraded);
2697         r5c_update_on_rdev_error(mddev);
2698 }
2699
2700 /*
2701  * Input: a 'big' sector number,
2702  * Output: index of the data and parity disk, and the sector # in them.
2703  */
2704 sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
2705                               int previous, int *dd_idx,
2706                               struct stripe_head *sh)
2707 {
2708         sector_t stripe, stripe2;
2709         sector_t chunk_number;
2710         unsigned int chunk_offset;
2711         int pd_idx, qd_idx;
2712         int ddf_layout = 0;
2713         sector_t new_sector;
2714         int algorithm = previous ? conf->prev_algo
2715                                  : conf->algorithm;
2716         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2717                                          : conf->chunk_sectors;
2718         int raid_disks = previous ? conf->previous_raid_disks
2719                                   : conf->raid_disks;
2720         int data_disks = raid_disks - conf->max_degraded;
2721
2722         /* First compute the information on this sector */
2723
2724         /*
2725          * Compute the chunk number and the sector offset inside the chunk
2726          */
2727         chunk_offset = sector_div(r_sector, sectors_per_chunk);
2728         chunk_number = r_sector;
2729
2730         /*
2731          * Compute the stripe number
2732          */
2733         stripe = chunk_number;
2734         *dd_idx = sector_div(stripe, data_disks);
2735         stripe2 = stripe;
2736         /*
2737          * Select the parity disk based on the user selected algorithm.
2738          */
2739         pd_idx = qd_idx = -1;
2740         switch(conf->level) {
2741         case 4:
2742                 pd_idx = data_disks;
2743                 break;
2744         case 5:
2745                 switch (algorithm) {
2746                 case ALGORITHM_LEFT_ASYMMETRIC:
2747                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
2748                         if (*dd_idx >= pd_idx)
2749                                 (*dd_idx)++;
2750                         break;
2751                 case ALGORITHM_RIGHT_ASYMMETRIC:
2752                         pd_idx = sector_div(stripe2, raid_disks);
2753                         if (*dd_idx >= pd_idx)
2754                                 (*dd_idx)++;
2755                         break;
2756                 case ALGORITHM_LEFT_SYMMETRIC:
2757                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
2758                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2759                         break;
2760                 case ALGORITHM_RIGHT_SYMMETRIC:
2761                         pd_idx = sector_div(stripe2, raid_disks);
2762                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2763                         break;
2764                 case ALGORITHM_PARITY_0:
2765                         pd_idx = 0;
2766                         (*dd_idx)++;
2767                         break;
2768                 case ALGORITHM_PARITY_N:
2769                         pd_idx = data_disks;
2770                         break;
2771                 default:
2772                         BUG();
2773                 }
2774                 break;
2775         case 6:
2776
2777                 switch (algorithm) {
2778                 case ALGORITHM_LEFT_ASYMMETRIC:
2779                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2780                         qd_idx = pd_idx + 1;
2781                         if (pd_idx == raid_disks-1) {
2782                                 (*dd_idx)++;    /* Q D D D P */
2783                                 qd_idx = 0;
2784                         } else if (*dd_idx >= pd_idx)
2785                                 (*dd_idx) += 2; /* D D P Q D */
2786                         break;
2787                 case ALGORITHM_RIGHT_ASYMMETRIC:
2788                         pd_idx = 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_LEFT_SYMMETRIC:
2797                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2798                         qd_idx = (pd_idx + 1) % raid_disks;
2799                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2800                         break;
2801                 case ALGORITHM_RIGHT_SYMMETRIC:
2802                         pd_idx = sector_div(stripe2, raid_disks);
2803                         qd_idx = (pd_idx + 1) % raid_disks;
2804                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2805                         break;
2806
2807                 case ALGORITHM_PARITY_0:
2808                         pd_idx = 0;
2809                         qd_idx = 1;
2810                         (*dd_idx) += 2;
2811                         break;
2812                 case ALGORITHM_PARITY_N:
2813                         pd_idx = data_disks;
2814                         qd_idx = data_disks + 1;
2815                         break;
2816
2817                 case ALGORITHM_ROTATING_ZERO_RESTART:
2818                         /* Exactly the same as RIGHT_ASYMMETRIC, but or
2819                          * of blocks for computing Q is different.
2820                          */
2821                         pd_idx = sector_div(stripe2, raid_disks);
2822                         qd_idx = pd_idx + 1;
2823                         if (pd_idx == raid_disks-1) {
2824                                 (*dd_idx)++;    /* Q D D D P */
2825                                 qd_idx = 0;
2826                         } else if (*dd_idx >= pd_idx)
2827                                 (*dd_idx) += 2; /* D D P Q D */
2828                         ddf_layout = 1;
2829                         break;
2830
2831                 case ALGORITHM_ROTATING_N_RESTART:
2832                         /* Same a left_asymmetric, by first stripe is
2833                          * D D D P Q  rather than
2834                          * Q D D D P
2835                          */
2836                         stripe2 += 1;
2837                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2838                         qd_idx = pd_idx + 1;
2839                         if (pd_idx == raid_disks-1) {
2840                                 (*dd_idx)++;    /* Q D D D P */
2841                                 qd_idx = 0;
2842                         } else if (*dd_idx >= pd_idx)
2843                                 (*dd_idx) += 2; /* D D P Q D */
2844                         ddf_layout = 1;
2845                         break;
2846
2847                 case ALGORITHM_ROTATING_N_CONTINUE:
2848                         /* Same as left_symmetric but Q is before P */
2849                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2850                         qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
2851                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2852                         ddf_layout = 1;
2853                         break;
2854
2855                 case ALGORITHM_LEFT_ASYMMETRIC_6:
2856                         /* RAID5 left_asymmetric, with Q on last device */
2857                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2858                         if (*dd_idx >= pd_idx)
2859                                 (*dd_idx)++;
2860                         qd_idx = raid_disks - 1;
2861                         break;
2862
2863                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
2864                         pd_idx = sector_div(stripe2, raid_disks-1);
2865                         if (*dd_idx >= pd_idx)
2866                                 (*dd_idx)++;
2867                         qd_idx = raid_disks - 1;
2868                         break;
2869
2870                 case ALGORITHM_LEFT_SYMMETRIC_6:
2871                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2872                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2873                         qd_idx = raid_disks - 1;
2874                         break;
2875
2876                 case ALGORITHM_RIGHT_SYMMETRIC_6:
2877                         pd_idx = sector_div(stripe2, raid_disks-1);
2878                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2879                         qd_idx = raid_disks - 1;
2880                         break;
2881
2882                 case ALGORITHM_PARITY_0_6:
2883                         pd_idx = 0;
2884                         (*dd_idx)++;
2885                         qd_idx = raid_disks - 1;
2886                         break;
2887
2888                 default:
2889                         BUG();
2890                 }
2891                 break;
2892         }
2893
2894         if (sh) {
2895                 sh->pd_idx = pd_idx;
2896                 sh->qd_idx = qd_idx;
2897                 sh->ddf_layout = ddf_layout;
2898         }
2899         /*
2900          * Finally, compute the new sector number
2901          */
2902         new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
2903         return new_sector;
2904 }
2905
2906 sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous)
2907 {
2908         struct r5conf *conf = sh->raid_conf;
2909         int raid_disks = sh->disks;
2910         int data_disks = raid_disks - conf->max_degraded;
2911         sector_t new_sector = sh->sector, check;
2912         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2913                                          : conf->chunk_sectors;
2914         int algorithm = previous ? conf->prev_algo
2915                                  : conf->algorithm;
2916         sector_t stripe;
2917         int chunk_offset;
2918         sector_t chunk_number;
2919         int dummy1, dd_idx = i;
2920         sector_t r_sector;
2921         struct stripe_head sh2;
2922
2923         chunk_offset = sector_div(new_sector, sectors_per_chunk);
2924         stripe = new_sector;
2925
2926         if (i == sh->pd_idx)
2927                 return 0;
2928         switch(conf->level) {
2929         case 4: break;
2930         case 5:
2931                 switch (algorithm) {
2932                 case ALGORITHM_LEFT_ASYMMETRIC:
2933                 case ALGORITHM_RIGHT_ASYMMETRIC:
2934                         if (i > sh->pd_idx)
2935                                 i--;
2936                         break;
2937                 case ALGORITHM_LEFT_SYMMETRIC:
2938                 case ALGORITHM_RIGHT_SYMMETRIC:
2939                         if (i < sh->pd_idx)
2940                                 i += raid_disks;
2941                         i -= (sh->pd_idx + 1);
2942                         break;
2943                 case ALGORITHM_PARITY_0:
2944                         i -= 1;
2945                         break;
2946                 case ALGORITHM_PARITY_N:
2947                         break;
2948                 default:
2949                         BUG();
2950                 }
2951                 break;
2952         case 6:
2953                 if (i == sh->qd_idx)
2954                         return 0; /* It is the Q disk */
2955                 switch (algorithm) {
2956                 case ALGORITHM_LEFT_ASYMMETRIC:
2957                 case ALGORITHM_RIGHT_ASYMMETRIC:
2958                 case ALGORITHM_ROTATING_ZERO_RESTART:
2959                 case ALGORITHM_ROTATING_N_RESTART:
2960                         if (sh->pd_idx == raid_disks-1)
2961                                 i--;    /* Q D D D P */
2962                         else if (i > sh->pd_idx)
2963                                 i -= 2; /* D D P Q D */
2964                         break;
2965                 case ALGORITHM_LEFT_SYMMETRIC:
2966                 case ALGORITHM_RIGHT_SYMMETRIC:
2967                         if (sh->pd_idx == raid_disks-1)
2968                                 i--; /* Q D D D P */
2969                         else {
2970                                 /* D D P Q D */
2971                                 if (i < sh->pd_idx)
2972                                         i += raid_disks;
2973                                 i -= (sh->pd_idx + 2);
2974                         }
2975                         break;
2976                 case ALGORITHM_PARITY_0:
2977                         i -= 2;
2978                         break;
2979                 case ALGORITHM_PARITY_N:
2980                         break;
2981                 case ALGORITHM_ROTATING_N_CONTINUE:
2982                         /* Like left_symmetric, but P is before Q */
2983                         if (sh->pd_idx == 0)
2984                                 i--;    /* P D D D Q */
2985                         else {
2986                                 /* D D Q P D */
2987                                 if (i < sh->pd_idx)
2988                                         i += raid_disks;
2989                                 i -= (sh->pd_idx + 1);
2990                         }
2991                         break;
2992                 case ALGORITHM_LEFT_ASYMMETRIC_6:
2993                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
2994                         if (i > sh->pd_idx)
2995                                 i--;
2996                         break;
2997                 case ALGORITHM_LEFT_SYMMETRIC_6:
2998                 case ALGORITHM_RIGHT_SYMMETRIC_6:
2999                         if (i < sh->pd_idx)
3000                                 i += data_disks + 1;
3001                         i -= (sh->pd_idx + 1);
3002                         break;
3003                 case ALGORITHM_PARITY_0_6:
3004                         i -= 1;
3005                         break;
3006                 default:
3007                         BUG();
3008                 }
3009                 break;
3010         }
3011
3012         chunk_number = stripe * data_disks + i;
3013         r_sector = chunk_number * sectors_per_chunk + chunk_offset;
3014
3015         check = raid5_compute_sector(conf, r_sector,
3016                                      previous, &dummy1, &sh2);
3017         if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
3018                 || sh2.qd_idx != sh->qd_idx) {
3019                 pr_warn("md/raid:%s: compute_blocknr: map not correct\n",
3020                         mdname(conf->mddev));
3021                 return 0;
3022         }
3023         return r_sector;
3024 }
3025
3026 /*
3027  * There are cases where we want handle_stripe_dirtying() and
3028  * schedule_reconstruction() to delay towrite to some dev of a stripe.
3029  *
3030  * This function checks whether we want to delay the towrite. Specifically,
3031  * we delay the towrite when:
3032  *
3033  *   1. degraded stripe has a non-overwrite to the missing dev, AND this
3034  *      stripe has data in journal (for other devices).
3035  *
3036  *      In this case, when reading data for the non-overwrite dev, it is
3037  *      necessary to handle complex rmw of write back cache (prexor with
3038  *      orig_page, and xor with page). To keep read path simple, we would
3039  *      like to flush data in journal to RAID disks first, so complex rmw
3040  *      is handled in the write patch (handle_stripe_dirtying).
3041  *
3042  *   2. when journal space is critical (R5C_LOG_CRITICAL=1)
3043  *
3044  *      It is important to be able to flush all stripes in raid5-cache.
3045  *      Therefore, we need reserve some space on the journal device for
3046  *      these flushes. If flush operation includes pending writes to the
3047  *      stripe, we need to reserve (conf->raid_disk + 1) pages per stripe
3048  *      for the flush out. If we exclude these pending writes from flush
3049  *      operation, we only need (conf->max_degraded + 1) pages per stripe.
3050  *      Therefore, excluding pending writes in these cases enables more
3051  *      efficient use of the journal device.
3052  *
3053  *      Note: To make sure the stripe makes progress, we only delay
3054  *      towrite for stripes with data already in journal (injournal > 0).
3055  *      When LOG_CRITICAL, stripes with injournal == 0 will be sent to
3056  *      no_space_stripes list.
3057  *
3058  */
3059 static inline bool delay_towrite(struct r5conf *conf,
3060                                  struct r5dev *dev,
3061                                  struct stripe_head_state *s)
3062 {
3063         /* case 1 above */
3064         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3065             !test_bit(R5_Insync, &dev->flags) && s->injournal)
3066                 return true;
3067         /* case 2 above */
3068         if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
3069             s->injournal > 0)
3070                 return true;
3071         return false;
3072 }
3073
3074 static void
3075 schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
3076                          int rcw, int expand)
3077 {
3078         int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx, disks = sh->disks;
3079         struct r5conf *conf = sh->raid_conf;
3080         int level = conf->level;
3081
3082         if (rcw) {
3083                 /*
3084                  * In some cases, handle_stripe_dirtying initially decided to
3085                  * run rmw and allocates extra page for prexor. However, rcw is
3086                  * cheaper later on. We need to free the extra page now,
3087                  * because we won't be able to do that in ops_complete_prexor().
3088                  */
3089                 r5c_release_extra_page(sh);
3090
3091                 for (i = disks; i--; ) {
3092                         struct r5dev *dev = &sh->dev[i];
3093
3094                         if (dev->towrite && !delay_towrite(conf, dev, s)) {
3095                                 set_bit(R5_LOCKED, &dev->flags);
3096                                 set_bit(R5_Wantdrain, &dev->flags);
3097                                 if (!expand)
3098                                         clear_bit(R5_UPTODATE, &dev->flags);
3099                                 s->locked++;
3100                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3101                                 set_bit(R5_LOCKED, &dev->flags);
3102                                 s->locked++;
3103                         }
3104                 }
3105                 /* if we are not expanding this is a proper write request, and
3106                  * there will be bios with new data to be drained into the
3107                  * stripe cache
3108                  */
3109                 if (!expand) {
3110                         if (!s->locked)
3111                                 /* False alarm, nothing to do */
3112                                 return;
3113                         sh->reconstruct_state = reconstruct_state_drain_run;
3114                         set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3115                 } else
3116                         sh->reconstruct_state = reconstruct_state_run;
3117
3118                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3119
3120                 if (s->locked + conf->max_degraded == disks)
3121                         if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
3122                                 atomic_inc(&conf->pending_full_writes);
3123         } else {
3124                 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
3125                         test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
3126                 BUG_ON(level == 6 &&
3127                         (!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
3128                            test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));
3129
3130                 for (i = disks; i--; ) {
3131                         struct r5dev *dev = &sh->dev[i];
3132                         if (i == pd_idx || i == qd_idx)
3133                                 continue;
3134
3135                         if (dev->towrite &&
3136                             (test_bit(R5_UPTODATE, &dev->flags) ||
3137                              test_bit(R5_Wantcompute, &dev->flags))) {
3138                                 set_bit(R5_Wantdrain, &dev->flags);
3139                                 set_bit(R5_LOCKED, &dev->flags);
3140                                 clear_bit(R5_UPTODATE, &dev->flags);
3141                                 s->locked++;
3142                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3143                                 set_bit(R5_LOCKED, &dev->flags);
3144                                 s->locked++;
3145                         }
3146                 }
3147                 if (!s->locked)
3148                         /* False alarm - nothing to do */
3149                         return;
3150                 sh->reconstruct_state = reconstruct_state_prexor_drain_run;
3151                 set_bit(STRIPE_OP_PREXOR, &s->ops_request);
3152                 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3153                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3154         }
3155
3156         /* keep the parity disk(s) locked while asynchronous operations
3157          * are in flight
3158          */
3159         set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
3160         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
3161         s->locked++;
3162
3163         if (level == 6) {
3164                 int qd_idx = sh->qd_idx;
3165                 struct r5dev *dev = &sh->dev[qd_idx];
3166
3167                 set_bit(R5_LOCKED, &dev->flags);
3168                 clear_bit(R5_UPTODATE, &dev->flags);
3169                 s->locked++;
3170         }
3171
3172         if (raid5_has_ppl(sh->raid_conf) && sh->ppl_page &&
3173             test_bit(STRIPE_OP_BIODRAIN, &s->ops_request) &&
3174             !test_bit(STRIPE_FULL_WRITE, &sh->state) &&
3175             test_bit(R5_Insync, &sh->dev[pd_idx].flags))
3176                 set_bit(STRIPE_OP_PARTIAL_PARITY, &s->ops_request);
3177
3178         pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
3179                 __func__, (unsigned long long)sh->sector,
3180                 s->locked, s->ops_request);
3181 }
3182
3183 /*
3184  * Each stripe/dev can have one or more bion attached.
3185  * toread/towrite point to the first in a chain.
3186  * The bi_next chain must be in order.
3187  */
3188 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx,
3189                           int forwrite, int previous)
3190 {
3191         struct bio **bip;
3192         struct r5conf *conf = sh->raid_conf;
3193         int firstwrite=0;
3194
3195         pr_debug("adding bi b#%llu to stripe s#%llu\n",
3196                 (unsigned long long)bi->bi_iter.bi_sector,
3197                 (unsigned long long)sh->sector);
3198
3199         spin_lock_irq(&sh->stripe_lock);
3200         /* Don't allow new IO added to stripes in batch list */
3201         if (sh->batch_head)
3202                 goto overlap;
3203         if (forwrite) {
3204                 bip = &sh->dev[dd_idx].towrite;
3205                 if (*bip == NULL)
3206                         firstwrite = 1;
3207         } else
3208                 bip = &sh->dev[dd_idx].toread;
3209         while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector) {
3210                 if (bio_end_sector(*bip) > bi->bi_iter.bi_sector)
3211                         goto overlap;
3212                 bip = & (*bip)->bi_next;
3213         }
3214         if (*bip && (*bip)->bi_iter.bi_sector < bio_end_sector(bi))
3215                 goto overlap;
3216
3217         if (forwrite && raid5_has_ppl(conf)) {
3218                 /*
3219                  * With PPL only writes to consecutive data chunks within a
3220                  * stripe are allowed because for a single stripe_head we can
3221                  * only have one PPL entry at a time, which describes one data
3222                  * range. Not really an overlap, but wait_for_overlap can be
3223                  * used to handle this.
3224                  */
3225                 sector_t sector;
3226                 sector_t first = 0;
3227                 sector_t last = 0;
3228                 int count = 0;
3229                 int i;
3230
3231                 for (i = 0; i < sh->disks; i++) {
3232                         if (i != sh->pd_idx &&
3233                             (i == dd_idx || sh->dev[i].towrite)) {
3234                                 sector = sh->dev[i].sector;
3235                                 if (count == 0 || sector < first)
3236                                         first = sector;
3237                                 if (sector > last)
3238                                         last = sector;
3239                                 count++;
3240                         }
3241                 }
3242
3243                 if (first + conf->chunk_sectors * (count - 1) != last)
3244                         goto overlap;
3245         }
3246
3247         if (!forwrite || previous)
3248                 clear_bit(STRIPE_BATCH_READY, &sh->state);
3249
3250         BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
3251         if (*bip)
3252                 bi->bi_next = *bip;
3253         *bip = bi;
3254         bio_inc_remaining(bi);
3255         md_write_inc(conf->mddev, bi);
3256
3257         if (forwrite) {
3258                 /* check if page is covered */
3259                 sector_t sector = sh->dev[dd_idx].sector;
3260                 for (bi=sh->dev[dd_idx].towrite;
3261                      sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
3262                              bi && bi->bi_iter.bi_sector <= sector;
3263                      bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
3264                         if (bio_end_sector(bi) >= sector)
3265                                 sector = bio_end_sector(bi);
3266                 }
3267                 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
3268                         if (!test_and_set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags))
3269                                 sh->overwrite_disks++;
3270         }
3271
3272         pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
3273                 (unsigned long long)(*bip)->bi_iter.bi_sector,
3274                 (unsigned long long)sh->sector, dd_idx);
3275
3276         if (conf->mddev->bitmap && firstwrite) {
3277                 /* Cannot hold spinlock over bitmap_startwrite,
3278                  * but must ensure this isn't added to a batch until
3279                  * we have added to the bitmap and set bm_seq.
3280                  * So set STRIPE_BITMAP_PENDING to prevent
3281                  * batching.
3282                  * If multiple add_stripe_bio() calls race here they
3283                  * much all set STRIPE_BITMAP_PENDING.  So only the first one
3284                  * to complete "bitmap_startwrite" gets to set
3285                  * STRIPE_BIT_DELAY.  This is important as once a stripe
3286                  * is added to a batch, STRIPE_BIT_DELAY cannot be changed
3287                  * any more.
3288                  */
3289                 set_bit(STRIPE_BITMAP_PENDING, &sh->state);
3290                 spin_unlock_irq(&sh->stripe_lock);
3291                 bitmap_startwrite(conf->mddev->bitmap, sh->sector,
3292                                   STRIPE_SECTORS, 0);
3293                 spin_lock_irq(&sh->stripe_lock);
3294                 clear_bit(STRIPE_BITMAP_PENDING, &sh->state);
3295                 if (!sh->batch_head) {
3296                         sh->bm_seq = conf->seq_flush+1;
3297                         set_bit(STRIPE_BIT_DELAY, &sh->state);
3298                 }
3299         }
3300         spin_unlock_irq(&sh->stripe_lock);
3301
3302         if (stripe_can_batch(sh))
3303                 stripe_add_to_batch_list(conf, sh);
3304         return 1;
3305
3306  overlap:
3307         set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
3308         spin_unlock_irq(&sh->stripe_lock);
3309         return 0;
3310 }
3311
3312 static void end_reshape(struct r5conf *conf);
3313
3314 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
3315                             struct stripe_head *sh)
3316 {
3317         int sectors_per_chunk =
3318                 previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
3319         int dd_idx;
3320         int chunk_offset = sector_div(stripe, sectors_per_chunk);
3321         int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
3322
3323         raid5_compute_sector(conf,
3324                              stripe * (disks - conf->max_degraded)
3325                              *sectors_per_chunk + chunk_offset,
3326                              previous,
3327                              &dd_idx, sh);
3328 }
3329
3330 static void
3331 handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
3332                      struct stripe_head_state *s, int disks)
3333 {
3334         int i;
3335         BUG_ON(sh->batch_head);
3336         for (i = disks; i--; ) {
3337                 struct bio *bi;
3338                 int bitmap_end = 0;
3339
3340                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
3341                         struct md_rdev *rdev;
3342                         rcu_read_lock();
3343                         rdev = rcu_dereference(conf->disks[i].rdev);
3344                         if (rdev && test_bit(In_sync, &rdev->flags) &&
3345                             !test_bit(Faulty, &rdev->flags))
3346                                 atomic_inc(&rdev->nr_pending);
3347                         else
3348                                 rdev = NULL;
3349                         rcu_read_unlock();
3350                         if (rdev) {
3351                                 if (!rdev_set_badblocks(
3352                                             rdev,
3353                                             sh->sector,
3354                                             STRIPE_SECTORS, 0))
3355                                         md_error(conf->mddev, rdev);
3356                                 rdev_dec_pending(rdev, conf->mddev);
3357                         }
3358                 }
3359                 spin_lock_irq(&sh->stripe_lock);
3360                 /* fail all writes first */
3361                 bi = sh->dev[i].towrite;
3362                 sh->dev[i].towrite = NULL;
3363                 sh->overwrite_disks = 0;
3364                 spin_unlock_irq(&sh->stripe_lock);
3365                 if (bi)
3366                         bitmap_end = 1;
3367
3368                 log_stripe_write_finished(sh);
3369
3370                 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3371                         wake_up(&conf->wait_for_overlap);
3372
3373                 while (bi && bi->bi_iter.bi_sector <
3374                         sh->dev[i].sector + STRIPE_SECTORS) {
3375                         struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
3376
3377                         bi->bi_error = -EIO;
3378                         md_write_end(conf->mddev);
3379                         bio_endio(bi);
3380                         bi = nextbi;
3381                 }
3382                 if (bitmap_end)
3383                         bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3384                                 STRIPE_SECTORS, 0, 0);
3385                 bitmap_end = 0;
3386                 /* and fail all 'written' */
3387                 bi = sh->dev[i].written;
3388                 sh->dev[i].written = NULL;
3389                 if (test_and_clear_bit(R5_SkipCopy, &sh->dev[i].flags)) {
3390                         WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
3391                         sh->dev[i].page = sh->dev[i].orig_page;
3392                 }
3393
3394                 if (bi) bitmap_end = 1;
3395                 while (bi && bi->bi_iter.bi_sector <
3396                        sh->dev[i].sector + STRIPE_SECTORS) {
3397                         struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
3398
3399                         bi->bi_error = -EIO;
3400                         md_write_end(conf->mddev);
3401                         bio_endio(bi);
3402                         bi = bi2;
3403                 }
3404
3405                 /* fail any reads if this device is non-operational and
3406                  * the data has not reached the cache yet.
3407                  */
3408                 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
3409                     s->failed > conf->max_degraded &&
3410                     (!test_bit(R5_Insync, &sh->dev[i].flags) ||
3411                       test_bit(R5_ReadError, &sh->dev[i].flags))) {
3412                         spin_lock_irq(&sh->stripe_lock);
3413                         bi = sh->dev[i].toread;
3414                         sh->dev[i].toread = NULL;
3415                         spin_unlock_irq(&sh->stripe_lock);
3416                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3417                                 wake_up(&conf->wait_for_overlap);
3418                         if (bi)
3419                                 s->to_read--;
3420                         while (bi && bi->bi_iter.bi_sector <
3421                                sh->dev[i].sector + STRIPE_SECTORS) {
3422                                 struct bio *nextbi =
3423                                         r5_next_bio(bi, sh->dev[i].sector);
3424
3425                                 bi->bi_error = -EIO;
3426                                 bio_endio(bi);
3427                                 bi = nextbi;
3428                         }
3429                 }
3430                 if (bitmap_end)
3431                         bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3432                                         STRIPE_SECTORS, 0, 0);
3433                 /* If we were in the middle of a write the parity block might
3434                  * still be locked - so just clear all R5_LOCKED flags
3435                  */
3436                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
3437         }
3438         s->to_write = 0;
3439         s->written = 0;
3440
3441         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3442                 if (atomic_dec_and_test(&conf->pending_full_writes))
3443                         md_wakeup_thread(conf->mddev->thread);
3444 }
3445
3446 static void
3447 handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
3448                    struct stripe_head_state *s)
3449 {
3450         int abort = 0;
3451         int i;
3452
3453         BUG_ON(sh->batch_head);
3454         clear_bit(STRIPE_SYNCING, &sh->state);
3455         if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
3456                 wake_up(&conf->wait_for_overlap);
3457         s->syncing = 0;
3458         s->replacing = 0;
3459         /* There is nothing more to do for sync/check/repair.
3460          * Don't even need to abort as that is handled elsewhere
3461          * if needed, and not always wanted e.g. if there is a known
3462          * bad block here.
3463          * For recover/replace we need to record a bad block on all
3464          * non-sync devices, or abort the recovery
3465          */
3466         if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
3467                 /* During recovery devices cannot be removed, so
3468                  * locking and refcounting of rdevs is not needed
3469                  */
3470                 rcu_read_lock();
3471                 for (i = 0; i < conf->raid_disks; i++) {
3472                         struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
3473                         if (rdev
3474                             && !test_bit(Faulty, &rdev->flags)
3475                             && !test_bit(In_sync, &rdev->flags)
3476                             && !rdev_set_badblocks(rdev, sh->sector,
3477                                                    STRIPE_SECTORS, 0))
3478                                 abort = 1;
3479                         rdev = rcu_dereference(conf->disks[i].replacement);
3480                         if (rdev
3481                             && !test_bit(Faulty, &rdev->flags)
3482                             && !test_bit(In_sync, &rdev->flags)
3483                             && !rdev_set_badblocks(rdev, sh->sector,
3484                                                    STRIPE_SECTORS, 0))
3485                                 abort = 1;
3486                 }
3487                 rcu_read_unlock();
3488                 if (abort)
3489                         conf->recovery_disabled =
3490                                 conf->mddev->recovery_disabled;
3491         }
3492         md_done_sync(conf->mddev, STRIPE_SECTORS, !abort);
3493 }
3494
3495 static int want_replace(struct stripe_head *sh, int disk_idx)
3496 {
3497         struct md_rdev *rdev;
3498         int rv = 0;
3499
3500         rcu_read_lock();
3501         rdev = rcu_dereference(sh->raid_conf->disks[disk_idx].replacement);
3502         if (rdev
3503             && !test_bit(Faulty, &rdev->flags)
3504             && !test_bit(In_sync, &rdev->flags)
3505             && (rdev->recovery_offset <= sh->sector
3506                 || rdev->mddev->recovery_cp <= sh->sector))
3507                 rv = 1;
3508         rcu_read_unlock();
3509         return rv;
3510 }
3511
3512 static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
3513                            int disk_idx, int disks)
3514 {
3515         struct r5dev *dev = &sh->dev[disk_idx];
3516         struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
3517                                   &sh->dev[s->failed_num[1]] };
3518         int i;
3519
3520
3521         if (test_bit(R5_LOCKED, &dev->flags) ||
3522             test_bit(R5_UPTODATE, &dev->flags))
3523                 /* No point reading this as we already have it or have
3524                  * decided to get it.
3525                  */
3526                 return 0;
3527
3528         if (dev->toread ||
3529             (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)))
3530                 /* We need this block to directly satisfy a request */
3531                 return 1;
3532
3533         if (s->syncing || s->expanding ||
3534             (s->replacing && want_replace(sh, disk_idx)))
3535                 /* When syncing, or expanding we read everything.
3536                  * When replacing, we need the replaced block.
3537                  */
3538                 return 1;
3539
3540         if ((s->failed >= 1 && fdev[0]->toread) ||
3541             (s->failed >= 2 && fdev[1]->toread))
3542                 /* If we want to read from a failed device, then
3543                  * we need to actually read every other device.
3544                  */
3545                 return 1;
3546
3547         /* Sometimes neither read-modify-write nor reconstruct-write
3548          * cycles can work.  In those cases we read every block we
3549          * can.  Then the parity-update is certain to have enough to
3550          * work with.
3551          * This can only be a problem when we need to write something,
3552          * and some device has failed.  If either of those tests
3553          * fail we need look no further.
3554          */
3555         if (!s->failed || !s->to_write)
3556                 return 0;
3557
3558         if (test_bit(R5_Insync, &dev->flags) &&
3559             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3560                 /* Pre-reads at not permitted until after short delay
3561                  * to gather multiple requests.  However if this
3562                  * device is no Insync, the block could only be computed
3563                  * and there is no need to delay that.
3564                  */
3565                 return 0;
3566
3567         for (i = 0; i < s->failed && i < 2; i++) {
3568                 if (fdev[i]->towrite &&
3569                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3570                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3571                         /* If we have a partial write to a failed
3572                          * device, then we will need to reconstruct
3573                          * the content of that device, so all other
3574                          * devices must be read.
3575                          */
3576                         return 1;
3577         }
3578
3579         /* If we are forced to do a reconstruct-write, either because
3580          * the current RAID6 implementation only supports that, or
3581          * because parity cannot be trusted and we are currently
3582          * recovering it, there is extra need to be careful.
3583          * If one of the devices that we would need to read, because
3584          * it is not being overwritten (and maybe not written at all)
3585          * is missing/faulty, then we need to read everything we can.
3586          */
3587         if (sh->raid_conf->level != 6 &&
3588             sh->sector < sh->raid_conf->mddev->recovery_cp)
3589                 /* reconstruct-write isn't being forced */
3590                 return 0;
3591         for (i = 0; i < s->failed && i < 2; i++) {
3592                 if (s->failed_num[i] != sh->pd_idx &&
3593                     s->failed_num[i] != sh->qd_idx &&
3594                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3595                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3596                         return 1;
3597         }
3598
3599         return 0;
3600 }
3601
3602 /* fetch_block - checks the given member device to see if its data needs
3603  * to be read or computed to satisfy a request.
3604  *
3605  * Returns 1 when no more member devices need to be checked, otherwise returns
3606  * 0 to tell the loop in handle_stripe_fill to continue
3607  */
3608 static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
3609                        int disk_idx, int disks)
3610 {
3611         struct r5dev *dev = &sh->dev[disk_idx];
3612
3613         /* is the data in this block needed, and can we get it? */
3614         if (need_this_block(sh, s, disk_idx, disks)) {
3615                 /* we would like to get this block, possibly by computing it,
3616                  * otherwise read it if the backing disk is insync
3617                  */
3618                 BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
3619                 BUG_ON(test_bit(R5_Wantread, &dev->flags));
3620                 BUG_ON(sh->batch_head);
3621
3622                 /*
3623                  * In the raid6 case if the only non-uptodate disk is P
3624                  * then we already trusted P to compute the other failed
3625                  * drives. It is safe to compute rather than re-read P.
3626                  * In other cases we only compute blocks from failed
3627                  * devices, otherwise check/repair might fail to detect
3628                  * a real inconsistency.
3629                  */
3630
3631                 if ((s->uptodate == disks - 1) &&
3632                     ((sh->qd_idx >= 0 && sh->pd_idx == disk_idx) ||
3633                     (s->failed && (disk_idx == s->failed_num[0] ||
3634                                    disk_idx == s->failed_num[1])))) {
3635                         /* have disk failed, and we're requested to fetch it;
3636                          * do compute it
3637                          */
3638                         pr_debug("Computing stripe %llu block %d\n",
3639                                (unsigned long long)sh->sector, disk_idx);
3640                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3641                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3642                         set_bit(R5_Wantcompute, &dev->flags);
3643                         sh->ops.target = disk_idx;
3644                         sh->ops.target2 = -1; /* no 2nd target */
3645                         s->req_compute = 1;
3646                         /* Careful: from this point on 'uptodate' is in the eye
3647                          * of raid_run_ops which services 'compute' operations
3648                          * before writes. R5_Wantcompute flags a block that will
3649                          * be R5_UPTODATE by the time it is needed for a
3650                          * subsequent operation.
3651                          */
3652                         s->uptodate++;
3653                         return 1;
3654                 } else if (s->uptodate == disks-2 && s->failed >= 2) {
3655                         /* Computing 2-failure is *very* expensive; only
3656                          * do it if failed >= 2
3657                          */
3658                         int other;
3659                         for (other = disks; other--; ) {
3660                                 if (other == disk_idx)
3661                                         continue;
3662                                 if (!test_bit(R5_UPTODATE,
3663                                       &sh->dev[other].flags))
3664                                         break;
3665                         }
3666                         BUG_ON(other < 0);
3667                         pr_debug("Computing stripe %llu blocks %d,%d\n",
3668                                (unsigned long long)sh->sector,
3669                                disk_idx, other);
3670                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3671                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3672                         set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
3673                         set_bit(R5_Wantcompute, &sh->dev[other].flags);
3674                         sh->ops.target = disk_idx;
3675                         sh->ops.target2 = other;
3676                         s->uptodate += 2;
3677                         s->req_compute = 1;
3678                         return 1;
3679                 } else if (test_bit(R5_Insync, &dev->flags)) {
3680                         set_bit(R5_LOCKED, &dev->flags);
3681                         set_bit(R5_Wantread, &dev->flags);
3682                         s->locked++;
3683                         pr_debug("Reading block %d (sync=%d)\n",
3684                                 disk_idx, s->syncing);
3685                 }
3686         }
3687
3688         return 0;
3689 }
3690
3691 /**
3692  * handle_stripe_fill - read or compute data to satisfy pending requests.
3693  */
3694 static void handle_stripe_fill(struct stripe_head *sh,
3695                                struct stripe_head_state *s,
3696                                int disks)
3697 {
3698         int i;
3699
3700         /* look for blocks to read/compute, skip this if a compute
3701          * is already in flight, or if the stripe contents are in the
3702          * midst of changing due to a write
3703          */
3704         if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
3705             !sh->reconstruct_state) {
3706
3707                 /*
3708                  * For degraded stripe with data in journal, do not handle
3709                  * read requests yet, instead, flush the stripe to raid
3710                  * disks first, this avoids handling complex rmw of write
3711                  * back cache (prexor with orig_page, and then xor with
3712                  * page) in the read path
3713                  */
3714                 if (s->injournal && s->failed) {
3715                         if (test_bit(STRIPE_R5C_CACHING, &sh->state))
3716                                 r5c_make_stripe_write_out(sh);
3717                         goto out;
3718                 }
3719
3720                 for (i = disks; i--; )
3721                         if (fetch_block(sh, s, i, disks))
3722                                 break;
3723         }
3724 out:
3725         set_bit(STRIPE_HANDLE, &sh->state);
3726 }
3727
3728 static void break_stripe_batch_list(struct stripe_head *head_sh,
3729                                     unsigned long handle_flags);
3730 /* handle_stripe_clean_event
3731  * any written block on an uptodate or failed drive can be returned.
3732  * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
3733  * never LOCKED, so we don't need to test 'failed' directly.
3734  */
3735 static void handle_stripe_clean_event(struct r5conf *conf,
3736         struct stripe_head *sh, int disks)
3737 {
3738         int i;
3739         struct r5dev *dev;
3740         int discard_pending = 0;
3741         struct stripe_head *head_sh = sh;
3742         bool do_endio = false;
3743
3744         for (i = disks; i--; )
3745                 if (sh->dev[i].written) {
3746                         dev = &sh->dev[i];
3747                         if (!test_bit(R5_LOCKED, &dev->flags) &&
3748                             (test_bit(R5_UPTODATE, &dev->flags) ||
3749                              test_bit(R5_Discard, &dev->flags) ||
3750                              test_bit(R5_SkipCopy, &dev->flags))) {
3751                                 /* We can return any write requests */
3752                                 struct bio *wbi, *wbi2;
3753                                 pr_debug("Return write for disc %d\n", i);
3754                                 if (test_and_clear_bit(R5_Discard, &dev->flags))
3755                                         clear_bit(R5_UPTODATE, &dev->flags);
3756                                 if (test_and_clear_bit(R5_SkipCopy, &dev->flags)) {
3757                                         WARN_ON(test_bit(R5_UPTODATE, &dev->flags));
3758                                 }
3759                                 do_endio = true;
3760
3761 returnbi:
3762                                 dev->page = dev->orig_page;
3763                                 wbi = dev->written;
3764                                 dev->written = NULL;
3765                                 while (wbi && wbi->bi_iter.bi_sector <
3766                                         dev->sector + STRIPE_SECTORS) {
3767                                         wbi2 = r5_next_bio(wbi, dev->sector);
3768                                         md_write_end(conf->mddev);
3769                                         bio_endio(wbi);
3770                                         wbi = wbi2;
3771                                 }
3772                                 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3773                                                 STRIPE_SECTORS,
3774                                          !test_bit(STRIPE_DEGRADED, &sh->state),
3775                                                 0);
3776                                 if (head_sh->batch_head) {
3777                                         sh = list_first_entry(&sh->batch_list,
3778                                                               struct stripe_head,
3779                                                               batch_list);
3780                                         if (sh != head_sh) {
3781                                                 dev = &sh->dev[i];
3782                                                 goto returnbi;
3783                                         }
3784                                 }
3785                                 sh = head_sh;
3786                                 dev = &sh->dev[i];
3787                         } else if (test_bit(R5_Discard, &dev->flags))
3788                                 discard_pending = 1;
3789                 }
3790
3791         log_stripe_write_finished(sh);
3792
3793         if (!discard_pending &&
3794             test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) {
3795                 int hash;
3796                 clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
3797                 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
3798                 if (sh->qd_idx >= 0) {
3799                         clear_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
3800                         clear_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags);
3801                 }
3802                 /* now that discard is done we can proceed with any sync */
3803                 clear_bit(STRIPE_DISCARD, &sh->state);
3804                 /*
3805                  * SCSI discard will change some bio fields and the stripe has
3806                  * no updated data, so remove it from hash list and the stripe
3807                  * will be reinitialized
3808                  */
3809 unhash:
3810                 hash = sh->hash_lock_index;
3811                 spin_lock_irq(conf->hash_locks + hash);
3812                 remove_hash(sh);
3813                 spin_unlock_irq(conf->hash_locks + hash);
3814                 if (head_sh->batch_head) {
3815                         sh = list_first_entry(&sh->batch_list,
3816                                               struct stripe_head, batch_list);
3817                         if (sh != head_sh)
3818                                         goto unhash;
3819                 }
3820                 sh = head_sh;
3821
3822                 if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
3823                         set_bit(STRIPE_HANDLE, &sh->state);
3824
3825         }
3826
3827         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3828                 if (atomic_dec_and_test(&conf->pending_full_writes))
3829                         md_wakeup_thread(conf->mddev->thread);
3830
3831         if (head_sh->batch_head && do_endio)
3832                 break_stripe_batch_list(head_sh, STRIPE_EXPAND_SYNC_FLAGS);
3833 }
3834
3835 /*
3836  * For RMW in write back cache, we need extra page in prexor to store the
3837  * old data. This page is stored in dev->orig_page.
3838  *
3839  * This function checks whether we have data for prexor. The exact logic
3840  * is:
3841  *       R5_UPTODATE && (!R5_InJournal || R5_OrigPageUPTDODATE)
3842  */
3843 static inline bool uptodate_for_rmw(struct r5dev *dev)
3844 {
3845         return (test_bit(R5_UPTODATE, &dev->flags)) &&
3846                 (!test_bit(R5_InJournal, &dev->flags) ||
3847                  test_bit(R5_OrigPageUPTDODATE, &dev->flags));
3848 }
3849
3850 static int handle_stripe_dirtying(struct r5conf *conf,
3851                                   struct stripe_head *sh,
3852                                   struct stripe_head_state *s,
3853                                   int disks)
3854 {
3855         int rmw = 0, rcw = 0, i;
3856         sector_t recovery_cp = conf->mddev->recovery_cp;
3857
3858         /* Check whether resync is now happening or should start.
3859          * If yes, then the array is dirty (after unclean shutdown or
3860          * initial creation), so parity in some stripes might be inconsistent.
3861          * In this case, we need to always do reconstruct-write, to ensure
3862          * that in case of drive failure or read-error correction, we
3863          * generate correct data from the parity.
3864          */
3865         if (conf->rmw_level == PARITY_DISABLE_RMW ||
3866             (recovery_cp < MaxSector && sh->sector >= recovery_cp &&
3867              s->failed == 0)) {
3868                 /* Calculate the real rcw later - for now make it
3869                  * look like rcw is cheaper
3870                  */
3871                 rcw = 1; rmw = 2;
3872                 pr_debug("force RCW rmw_level=%u, recovery_cp=%llu sh->sector=%llu\n",
3873                          conf->rmw_level, (unsigned long long)recovery_cp,
3874                          (unsigned long long)sh->sector);
3875         } else for (i = disks; i--; ) {
3876                 /* would I have to read this buffer for read_modify_write */
3877                 struct r5dev *dev = &sh->dev[i];
3878                 if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3879                      i == sh->pd_idx || i == sh->qd_idx ||
3880                      test_bit(R5_InJournal, &dev->flags)) &&
3881                     !test_bit(R5_LOCKED, &dev->flags) &&
3882                     !(uptodate_for_rmw(dev) ||
3883                       test_bit(R5_Wantcompute, &dev->flags))) {
3884                         if (test_bit(R5_Insync, &dev->flags))
3885                                 rmw++;
3886                         else
3887                                 rmw += 2*disks;  /* cannot read it */
3888                 }
3889                 /* Would I have to read this buffer for reconstruct_write */
3890                 if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3891                     i != sh->pd_idx && i != sh->qd_idx &&
3892                     !test_bit(R5_LOCKED, &dev->flags) &&
3893                     !(test_bit(R5_UPTODATE, &dev->flags) ||
3894                       test_bit(R5_Wantcompute, &dev->flags))) {
3895                         if (test_bit(R5_Insync, &dev->flags))
3896                                 rcw++;
3897                         else
3898                                 rcw += 2*disks;
3899                 }
3900         }
3901
3902         pr_debug("for sector %llu state 0x%lx, rmw=%d rcw=%d\n",
3903                  (unsigned long long)sh->sector, sh->state, rmw, rcw);
3904         set_bit(STRIPE_HANDLE, &sh->state);
3905         if ((rmw < rcw || (rmw == rcw && conf->rmw_level == PARITY_PREFER_RMW)) && rmw > 0) {
3906                 /* prefer read-modify-write, but need to get some data */
3907                 if (conf->mddev->queue)
3908                         blk_add_trace_msg(conf->mddev->queue,
3909                                           "raid5 rmw %llu %d",
3910                                           (unsigned long long)sh->sector, rmw);
3911                 for (i = disks; i--; ) {
3912                         struct r5dev *dev = &sh->dev[i];
3913                         if (test_bit(R5_InJournal, &dev->flags) &&
3914                             dev->page == dev->orig_page &&
3915                             !test_bit(R5_LOCKED, &sh->dev[sh->pd_idx].flags)) {
3916                                 /* alloc page for prexor */
3917                                 struct page *p = alloc_page(GFP_NOIO);
3918
3919                                 if (p) {
3920                                         dev->orig_page = p;
3921                                         continue;
3922                                 }
3923
3924                                 /*
3925                                  * alloc_page() failed, try use
3926                                  * disk_info->extra_page
3927                                  */
3928                                 if (!test_and_set_bit(R5C_EXTRA_PAGE_IN_USE,
3929                                                       &conf->cache_state)) {
3930                                         r5c_use_extra_page(sh);
3931                                         break;
3932                                 }
3933
3934                                 /* extra_page in use, add to delayed_list */
3935                                 set_bit(STRIPE_DELAYED, &sh->state);
3936                                 s->waiting_extra_page = 1;
3937                                 return -EAGAIN;
3938                         }
3939                 }
3940
3941                 for (i = disks; i--; ) {
3942                         struct r5dev *dev = &sh->dev[i];
3943                         if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3944                              i == sh->pd_idx || i == sh->qd_idx ||
3945                              test_bit(R5_InJournal, &dev->flags)) &&
3946                             !test_bit(R5_LOCKED, &dev->flags) &&
3947                             !(uptodate_for_rmw(dev) ||
3948                               test_bit(R5_Wantcompute, &dev->flags)) &&
3949                             test_bit(R5_Insync, &dev->flags)) {
3950                                 if (test_bit(STRIPE_PREREAD_ACTIVE,
3951                                              &sh->state)) {
3952                                         pr_debug("Read_old block %d for r-m-w\n",
3953                                                  i);
3954                                         set_bit(R5_LOCKED, &dev->flags);
3955                                         set_bit(R5_Wantread, &dev->flags);
3956                                         s->locked++;
3957                                 } else {
3958                                         set_bit(STRIPE_DELAYED, &sh->state);
3959                                         set_bit(STRIPE_HANDLE, &sh->state);
3960                                 }
3961                         }
3962                 }
3963         }
3964         if ((rcw < rmw || (rcw == rmw && conf->rmw_level != PARITY_PREFER_RMW)) && rcw > 0) {
3965                 /* want reconstruct write, but need to get some data */
3966                 int qread =0;
3967                 rcw = 0;
3968                 for (i = disks; i--; ) {
3969                         struct r5dev *dev = &sh->dev[i];
3970                         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3971                             i != sh->pd_idx && i != sh->qd_idx &&
3972                             !test_bit(R5_LOCKED, &dev->flags) &&
3973                             !(test_bit(R5_UPTODATE, &dev->flags) ||
3974                               test_bit(R5_Wantcompute, &dev->flags))) {
3975                                 rcw++;
3976                                 if (test_bit(R5_Insync, &dev->flags) &&
3977                                     test_bit(STRIPE_PREREAD_ACTIVE,
3978                                              &sh->state)) {
3979                                         pr_debug("Read_old block "
3980                                                 "%d for Reconstruct\n", i);
3981                                         set_bit(R5_LOCKED, &dev->flags);
3982                                         set_bit(R5_Wantread, &dev->flags);
3983                                         s->locked++;
3984                                         qread++;
3985                                 } else {
3986                                         set_bit(STRIPE_DELAYED, &sh->state);
3987                                         set_bit(STRIPE_HANDLE, &sh->state);
3988                                 }
3989                         }
3990                 }
3991                 if (rcw && conf->mddev->queue)
3992                         blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
3993                                           (unsigned long long)sh->sector,
3994                                           rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
3995         }
3996
3997         if (rcw > disks && rmw > disks &&
3998             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3999                 set_bit(STRIPE_DELAYED, &sh->state);
4000
4001         /* now if nothing is locked, and if we have enough data,
4002          * we can start a write request
4003          */
4004         /* since handle_stripe can be called at any time we need to handle the
4005          * case where a compute block operation has been submitted and then a
4006          * subsequent call wants to start a write request.  raid_run_ops only
4007          * handles the case where compute block and reconstruct are requested
4008          * simultaneously.  If this is not the case then new writes need to be
4009          * held off until the compute completes.
4010          */
4011         if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
4012             (s->locked == 0 && (rcw == 0 || rmw == 0) &&
4013              !test_bit(STRIPE_BIT_DELAY, &sh->state)))
4014                 schedule_reconstruction(sh, s, rcw == 0, 0);
4015         return 0;
4016 }
4017
4018 static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
4019                                 struct stripe_head_state *s, int disks)
4020 {
4021         struct r5dev *dev = NULL;
4022
4023         BUG_ON(sh->batch_head);
4024         set_bit(STRIPE_HANDLE, &sh->state);
4025
4026         switch (sh->check_state) {
4027         case check_state_idle:
4028                 /* start a new check operation if there are no failures */
4029                 if (s->failed == 0) {
4030                         BUG_ON(s->uptodate != disks);
4031                         sh->check_state = check_state_run;
4032                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4033                         clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4034                         s->uptodate--;
4035                         break;
4036                 }
4037                 dev = &sh->dev[s->failed_num[0]];
4038                 /* fall through */
4039         case check_state_compute_result:
4040                 sh->check_state = check_state_idle;
4041                 if (!dev)
4042                         dev = &sh->dev[sh->pd_idx];
4043
4044                 /* check that a write has not made the stripe insync */
4045                 if (test_bit(STRIPE_INSYNC, &sh->state))
4046                         break;
4047
4048                 /* either failed parity check, or recovery is happening */
4049                 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
4050                 BUG_ON(s->uptodate != disks);
4051
4052                 set_bit(R5_LOCKED, &dev->flags);
4053                 s->locked++;
4054                 set_bit(R5_Wantwrite, &dev->flags);
4055
4056                 clear_bit(STRIPE_DEGRADED, &sh->state);
4057                 set_bit(STRIPE_INSYNC, &sh->state);
4058                 break;
4059         case check_state_run:
4060                 break; /* we will be called again upon completion */
4061         case check_state_check_result:
4062                 sh->check_state = check_state_idle;
4063
4064                 /* if a failure occurred during the check operation, leave
4065                  * STRIPE_INSYNC not set and let the stripe be handled again
4066                  */
4067                 if (s->failed)
4068                         break;
4069
4070                 /* handle a successful check operation, if parity is correct
4071                  * we are done.  Otherwise update the mismatch count and repair
4072                  * parity if !MD_RECOVERY_CHECK
4073                  */
4074                 if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
4075                         /* parity is correct (on disc,
4076                          * not in buffer any more)
4077                          */
4078                         set_bit(STRIPE_INSYNC, &sh->state);
4079                 else {
4080                         atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
4081                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
4082                                 /* don't try to repair!! */
4083                                 set_bit(STRIPE_INSYNC, &sh->state);
4084                         else {
4085                                 sh->check_state = check_state_compute_run;
4086                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4087                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4088                                 set_bit(R5_Wantcompute,
4089                                         &sh->dev[sh->pd_idx].flags);
4090                                 sh->ops.target = sh->pd_idx;
4091                                 sh->ops.target2 = -1;
4092                                 s->uptodate++;
4093                         }
4094                 }
4095                 break;
4096         case check_state_compute_run:
4097                 break;
4098         default:
4099                 pr_err("%s: unknown check_state: %d sector: %llu\n",
4100                        __func__, sh->check_state,
4101                        (unsigned long long) sh->sector);
4102                 BUG();
4103         }
4104 }
4105
4106 static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
4107                                   struct stripe_head_state *s,
4108                                   int disks)
4109 {
4110         int pd_idx = sh->pd_idx;
4111         int qd_idx = sh->qd_idx;
4112         struct r5dev *dev;
4113
4114         BUG_ON(sh->batch_head);
4115         set_bit(STRIPE_HANDLE, &sh->state);
4116
4117         BUG_ON(s->failed > 2);
4118
4119         /* Want to check and possibly repair P and Q.
4120          * However there could be one 'failed' device, in which
4121          * case we can only check one of them, possibly using the
4122          * other to generate missing data
4123          */
4124
4125         switch (sh->check_state) {
4126         case check_state_idle:
4127                 /* start a new check operation if there are < 2 failures */
4128                 if (s->failed == s->q_failed) {
4129                         /* The only possible failed device holds Q, so it
4130                          * makes sense to check P (If anything else were failed,
4131                          * we would have used P to recreate it).
4132                          */
4133                         sh->check_state = check_state_run;
4134                 }
4135                 if (!s->q_failed && s->failed < 2) {
4136                         /* Q is not failed, and we didn't use it to generate
4137                          * anything, so it makes sense to check it
4138                          */
4139                         if (sh->check_state == check_state_run)
4140                                 sh->check_state = check_state_run_pq;
4141                         else
4142                                 sh->check_state = check_state_run_q;
4143                 }
4144
4145                 /* discard potentially stale zero_sum_result */
4146                 sh->ops.zero_sum_result = 0;
4147
4148                 if (sh->check_state == check_state_run) {
4149                         /* async_xor_zero_sum destroys the contents of P */
4150                         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
4151                         s->uptodate--;
4152                 }
4153                 if (sh->check_state >= check_state_run &&
4154                     sh->check_state <= check_state_run_pq) {
4155                         /* async_syndrome_zero_sum preserves P and Q, so
4156                          * no need to mark them !uptodate here
4157                          */
4158                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4159                         break;
4160                 }
4161
4162                 /* we have 2-disk failure */
4163                 BUG_ON(s->failed != 2);
4164                 /* fall through */
4165         case check_state_compute_result:
4166                 sh->check_state = check_state_idle;
4167
4168                 /* check that a write has not made the stripe insync */
4169                 if (test_bit(STRIPE_INSYNC, &sh->state))
4170                         break;
4171
4172                 /* now write out any block on a failed drive,
4173                  * or P or Q if they were recomputed
4174                  */
4175                 BUG_ON(s->uptodate < disks - 1); /* We don't need Q to recover */
4176                 if (s->failed == 2) {
4177                         dev = &sh->dev[s->failed_num[1]];
4178                         s->locked++;
4179                         set_bit(R5_LOCKED, &dev->flags);
4180                         set_bit(R5_Wantwrite, &dev->flags);
4181                 }
4182                 if (s->failed >= 1) {
4183                         dev = &sh->dev[s->failed_num[0]];
4184                         s->locked++;
4185                         set_bit(R5_LOCKED, &dev->flags);
4186                         set_bit(R5_Wantwrite, &dev->flags);
4187                 }
4188                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4189                         dev = &sh->dev[pd_idx];
4190                         s->locked++;
4191                         set_bit(R5_LOCKED, &dev->flags);
4192                         set_bit(R5_Wantwrite, &dev->flags);
4193                 }
4194                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4195                         dev = &sh->dev[qd_idx];
4196                         s->locked++;
4197                         set_bit(R5_LOCKED, &dev->flags);
4198                         set_bit(R5_Wantwrite, &dev->flags);
4199                 }
4200                 clear_bit(STRIPE_DEGRADED, &sh->state);
4201
4202                 set_bit(STRIPE_INSYNC, &sh->state);
4203                 break;
4204         case check_state_run:
4205         case check_state_run_q:
4206         case check_state_run_pq:
4207                 break; /* we will be called again upon completion */
4208         case check_state_check_result:
4209                 sh->check_state = check_state_idle;
4210
4211                 /* handle a successful check operation, if parity is correct
4212                  * we are done.  Otherwise update the mismatch count and repair
4213                  * parity if !MD_RECOVERY_CHECK
4214                  */
4215                 if (sh->ops.zero_sum_result == 0) {
4216                         /* both parities are correct */
4217                         if (!s->failed)
4218                                 set_bit(STRIPE_INSYNC, &sh->state);
4219                         else {
4220                                 /* in contrast to the raid5 case we can validate
4221                                  * parity, but still have a failure to write
4222                                  * back
4223                                  */
4224                                 sh->check_state = check_state_compute_result;
4225                                 /* Returning at this point means that we may go
4226                                  * off and bring p and/or q uptodate again so
4227                                  * we make sure to check zero_sum_result again
4228                                  * to verify if p or q need writeback
4229                                  */
4230                         }
4231                 } else {
4232                         atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
4233                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery))
4234                                 /* don't try to repair!! */
4235                                 set_bit(STRIPE_INSYNC, &sh->state);
4236                         else {
4237                                 int *target = &sh->ops.target;
4238
4239                                 sh->ops.target = -1;
4240                                 sh->ops.target2 = -1;
4241                                 sh->check_state = check_state_compute_run;
4242                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4243                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4244                                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4245                                         set_bit(R5_Wantcompute,
4246                                                 &sh->dev[pd_idx].flags);
4247                                         *target = pd_idx;
4248                                         target = &sh->ops.target2;
4249                                         s->uptodate++;
4250                                 }
4251                                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4252                                         set_bit(R5_Wantcompute,
4253                                                 &sh->dev[qd_idx].flags);
4254                                         *target = qd_idx;
4255                                         s->uptodate++;
4256                                 }
4257                         }
4258                 }
4259                 break;
4260         case check_state_compute_run:
4261                 break;
4262         default:
4263                 pr_warn("%s: unknown check_state: %d sector: %llu\n",
4264                         __func__, sh->check_state,
4265                         (unsigned long long) sh->sector);
4266                 BUG();
4267         }
4268 }
4269
4270 static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
4271 {
4272         int i;
4273
4274         /* We have read all the blocks in this stripe and now we need to
4275          * copy some of them into a target stripe for expand.
4276          */
4277         struct dma_async_tx_descriptor *tx = NULL;
4278         BUG_ON(sh->batch_head);
4279         clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
4280         for (i = 0; i < sh->disks; i++)
4281                 if (i != sh->pd_idx && i != sh->qd_idx) {
4282                         int dd_idx, j;
4283                         struct stripe_head *sh2;
4284                         struct async_submit_ctl submit;
4285
4286                         sector_t bn = raid5_compute_blocknr(sh, i, 1);
4287                         sector_t s = raid5_compute_sector(conf, bn, 0,
4288                                                           &dd_idx, NULL);
4289                         sh2 = raid5_get_active_stripe(conf, s, 0, 1, 1);
4290                         if (sh2 == NULL)
4291                                 /* so far only the early blocks of this stripe
4292                                  * have been requested.  When later blocks
4293                                  * get requested, we will try again
4294                                  */
4295                                 continue;
4296                         if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
4297                            test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
4298                                 /* must have already done this block */
4299                                 raid5_release_stripe(sh2);
4300                                 continue;
4301                         }
4302
4303                         /* place all the copies on one channel */
4304                         init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
4305                         tx = async_memcpy(sh2->dev[dd_idx].page,
4306                                           sh->dev[i].page, 0, 0, STRIPE_SIZE,
4307                                           &submit);
4308
4309                         set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
4310                         set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
4311                         for (j = 0; j < conf->raid_disks; j++)
4312                                 if (j != sh2->pd_idx &&
4313                                     j != sh2->qd_idx &&
4314                                     !test_bit(R5_Expanded, &sh2->dev[j].flags))
4315                                         break;
4316                         if (j == conf->raid_disks) {
4317                                 set_bit(STRIPE_EXPAND_READY, &sh2->state);
4318                                 set_bit(STRIPE_HANDLE, &sh2->state);
4319                         }
4320                         raid5_release_stripe(sh2);
4321
4322                 }
4323         /* done submitting copies, wait for them to complete */
4324         async_tx_quiesce(&tx);
4325 }
4326
4327 /*
4328  * handle_stripe - do things to a stripe.
4329  *
4330  * We lock the stripe by setting STRIPE_ACTIVE and then examine the
4331  * state of various bits to see what needs to be done.
4332  * Possible results:
4333  *    return some read requests which now have data
4334  *    return some write requests which are safely on storage
4335  *    schedule a read on some buffers
4336  *    schedule a write of some buffers
4337  *    return confirmation of parity correctness
4338  *
4339  */
4340
4341 static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
4342 {
4343         struct r5conf *conf = sh->raid_conf;
4344         int disks = sh->disks;
4345         struct r5dev *dev;
4346         int i;
4347         int do_recovery = 0;
4348
4349         memset(s, 0, sizeof(*s));
4350
4351         s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state) && !sh->batch_head;
4352         s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state) && !sh->batch_head;
4353         s->failed_num[0] = -1;
4354         s->failed_num[1] = -1;
4355         s->log_failed = r5l_log_disk_error(conf);
4356
4357         /* Now to look around and see what can be done */
4358         rcu_read_lock();
4359         for (i=disks; i--; ) {
4360                 struct md_rdev *rdev;
4361                 sector_t first_bad;
4362                 int bad_sectors;
4363                 int is_bad = 0;
4364
4365                 dev = &sh->dev[i];
4366
4367                 pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
4368                          i, dev->flags,
4369                          dev->toread, dev->towrite, dev->written);
4370                 /* maybe we can reply to a read
4371                  *
4372                  * new wantfill requests are only permitted while
4373                  * ops_complete_biofill is guaranteed to be inactive
4374                  */
4375                 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
4376                     !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
4377                         set_bit(R5_Wantfill, &dev->flags);
4378
4379                 /* now count some things */
4380                 if (test_bit(R5_LOCKED, &dev->flags))
4381                         s->locked++;
4382                 if (test_bit(R5_UPTODATE, &dev->flags))
4383                         s->uptodate++;
4384                 if (test_bit(R5_Wantcompute, &dev->flags)) {
4385                         s->compute++;
4386                         BUG_ON(s->compute > 2);
4387                 }
4388
4389                 if (test_bit(R5_Wantfill, &dev->flags))
4390                         s->to_fill++;
4391                 else if (dev->toread)
4392                         s->to_read++;
4393                 if (dev->towrite) {
4394                         s->to_write++;
4395                         if (!test_bit(R5_OVERWRITE, &dev->flags))
4396                                 s->non_overwrite++;
4397                 }
4398                 if (dev->written)
4399                         s->written++;
4400                 /* Prefer to use the replacement for reads, but only
4401                  * if it is recovered enough and has no bad blocks.
4402                  */
4403                 rdev = rcu_dereference(conf->disks[i].replacement);
4404                 if (rdev && !test_bit(Faulty, &rdev->flags) &&
4405                     rdev->recovery_offset >= sh->sector + STRIPE_SECTORS &&
4406                     !is_badblock(rdev, sh->sector, STRIPE_SECTORS,
4407                                  &first_bad, &bad_sectors))
4408                         set_bit(R5_ReadRepl, &dev->flags);
4409                 else {
4410                         if (rdev && !test_bit(Faulty, &rdev->flags))
4411                                 set_bit(R5_NeedReplace, &dev->flags);
4412                         else
4413                                 clear_bit(R5_NeedReplace, &dev->flags);
4414                         rdev = rcu_dereference(conf->disks[i].rdev);
4415                         clear_bit(R5_ReadRepl, &dev->flags);
4416                 }
4417                 if (rdev && test_bit(Faulty, &rdev->flags))
4418                         rdev = NULL;
4419                 if (rdev) {
4420                         is_bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
4421                                              &first_bad, &bad_sectors);
4422                         if (s->blocked_rdev == NULL
4423                             && (test_bit(Blocked, &rdev->flags)
4424                                 || is_bad < 0)) {
4425                                 if (is_bad < 0)
4426                                         set_bit(BlockedBadBlocks,
4427                                                 &rdev->flags);
4428                                 s->blocked_rdev = rdev;
4429                                 atomic_inc(&rdev->nr_pending);
4430                         }
4431                 }
4432                 clear_bit(R5_Insync, &dev->flags);
4433                 if (!rdev)
4434                         /* Not in-sync */;
4435                 else if (is_bad) {
4436                         /* also not in-sync */
4437                         if (!test_bit(WriteErrorSeen, &rdev->flags) &&
4438                             test_bit(R5_UPTODATE, &dev->flags)) {
4439                                 /* treat as in-sync, but with a read error
4440                                  * which we can now try to correct
4441                                  */
4442                                 set_bit(R5_Insync, &dev->flags);
4443                                 set_bit(R5_ReadError, &dev->flags);
4444                         }
4445                 } else if (test_bit(In_sync, &rdev->flags))
4446                         set_bit(R5_Insync, &dev->flags);
4447                 else if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
4448                         /* in sync if before recovery_offset */
4449                         set_bit(R5_Insync, &dev->flags);
4450                 else if (test_bit(R5_UPTODATE, &dev->flags) &&
4451                          test_bit(R5_Expanded, &dev->flags))
4452                         /* If we've reshaped into here, we assume it is Insync.
4453                          * We will shortly update recovery_offset to make
4454                          * it official.
4455                          */
4456                         set_bit(R5_Insync, &dev->flags);
4457
4458                 if (test_bit(R5_WriteError, &dev->flags)) {
4459                         /* This flag does not apply to '.replacement'
4460                          * only to .rdev, so make sure to check that*/
4461                         struct md_rdev *rdev2 = rcu_dereference(
4462                                 conf->disks[i].rdev);
4463                         if (rdev2 == rdev)
4464                                 clear_bit(R5_Insync, &dev->flags);
4465                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4466                                 s->handle_bad_blocks = 1;
4467                                 atomic_inc(&rdev2->nr_pending);
4468                         } else
4469                                 clear_bit(R5_WriteError, &dev->flags);
4470                 }
4471                 if (test_bit(R5_MadeGood, &dev->flags)) {
4472                         /* This flag does not apply to '.replacement'
4473                          * only to .rdev, so make sure to check that*/
4474                         struct md_rdev *rdev2 = rcu_dereference(
4475                                 conf->disks[i].rdev);
4476                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4477                                 s->handle_bad_blocks = 1;
4478                                 atomic_inc(&rdev2->nr_pending);
4479                         } else
4480                                 clear_bit(R5_MadeGood, &dev->flags);
4481                 }
4482                 if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
4483                         struct md_rdev *rdev2 = rcu_dereference(
4484                                 conf->disks[i].replacement);
4485                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4486                                 s->handle_bad_blocks = 1;
4487                                 atomic_inc(&rdev2->nr_pending);
4488                         } else
4489                                 clear_bit(R5_MadeGoodRepl, &dev->flags);
4490                 }
4491                 if (!test_bit(R5_Insync, &dev->flags)) {
4492                         /* The ReadError flag will just be confusing now */
4493                         clear_bit(R5_ReadError, &dev->flags);
4494                         clear_bit(R5_ReWrite, &dev->flags);
4495                 }
4496                 if (test_bit(R5_ReadError, &dev->flags))
4497                         clear_bit(R5_Insync, &dev->flags);
4498                 if (!test_bit(R5_Insync, &dev->flags)) {
4499                         if (s->failed < 2)
4500                                 s->failed_num[s->failed] = i;
4501                         s->failed++;
4502                         if (rdev && !test_bit(Faulty, &rdev->flags))
4503                                 do_recovery = 1;
4504                 }
4505
4506                 if (test_bit(R5_InJournal, &dev->flags))
4507                         s->injournal++;
4508                 if (test_bit(R5_InJournal, &dev->flags) && dev->written)
4509                         s->just_cached++;
4510         }
4511         if (test_bit(STRIPE_SYNCING, &sh->state)) {
4512                 /* If there is a failed device being replaced,
4513                  *     we must be recovering.
4514                  * else if we are after recovery_cp, we must be syncing
4515                  * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
4516                  * else we can only be replacing
4517                  * sync and recovery both need to read all devices, and so
4518                  * use the same flag.
4519                  */
4520                 if (do_recovery ||
4521                     sh->sector >= conf->mddev->recovery_cp ||
4522                     test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
4523                         s->syncing = 1;
4524                 else
4525                         s->replacing = 1;
4526         }
4527         rcu_read_unlock();
4528 }
4529
4530 static int clear_batch_ready(struct stripe_head *sh)
4531 {
4532         /* Return '1' if this is a member of batch, or
4533          * '0' if it is a lone stripe or a head which can now be
4534          * handled.
4535          */
4536         struct stripe_head *tmp;
4537         if (!test_and_clear_bit(STRIPE_BATCH_READY, &sh->state))
4538                 return (sh->batch_head && sh->batch_head != sh);
4539         spin_lock(&sh->stripe_lock);
4540         if (!sh->batch_head) {
4541                 spin_unlock(&sh->stripe_lock);
4542                 return 0;
4543         }
4544
4545         /*
4546          * this stripe could be added to a batch list before we check
4547          * BATCH_READY, skips it
4548          */
4549         if (sh->batch_head != sh) {
4550                 spin_unlock(&sh->stripe_lock);
4551                 return 1;
4552         }
4553         spin_lock(&sh->batch_lock);
4554         list_for_each_entry(tmp, &sh->batch_list, batch_list)
4555                 clear_bit(STRIPE_BATCH_READY, &tmp->state);
4556         spin_unlock(&sh->batch_lock);
4557         spin_unlock(&sh->stripe_lock);
4558
4559         /*
4560          * BATCH_READY is cleared, no new stripes can be added.
4561          * batch_list can be accessed without lock
4562          */
4563         return 0;
4564 }
4565
4566 static void break_stripe_batch_list(struct stripe_head *head_sh,
4567                                     unsigned long handle_flags)
4568 {
4569         struct stripe_head *sh, *next;
4570         int i;
4571         int do_wakeup = 0;
4572
4573         list_for_each_entry_safe(sh, next, &head_sh->batch_list, batch_list) {
4574
4575                 list_del_init(&sh->batch_list);
4576
4577                 WARN_ONCE(sh->state & ((1 << STRIPE_ACTIVE) |
4578                                           (1 << STRIPE_SYNCING) |
4579                                           (1 << STRIPE_REPLACED) |
4580                                           (1 << STRIPE_DELAYED) |
4581                                           (1 << STRIPE_BIT_DELAY) |
4582                                           (1 << STRIPE_FULL_WRITE) |
4583                                           (1 << STRIPE_BIOFILL_RUN) |
4584                                           (1 << STRIPE_COMPUTE_RUN)  |
4585                                           (1 << STRIPE_OPS_REQ_PENDING) |
4586                                           (1 << STRIPE_DISCARD) |
4587                                           (1 << STRIPE_BATCH_READY) |
4588                                           (1 << STRIPE_BATCH_ERR) |
4589                                           (1 << STRIPE_BITMAP_PENDING)),
4590                         "stripe state: %lx\n", sh->state);
4591                 WARN_ONCE(head_sh->state & ((1 << STRIPE_DISCARD) |
4592                                               (1 << STRIPE_REPLACED)),
4593                         "head stripe state: %lx\n", head_sh->state);
4594
4595                 set_mask_bits(&sh->state, ~(STRIPE_EXPAND_SYNC_FLAGS |
4596                                             (1 << STRIPE_PREREAD_ACTIVE) |
4597                                             (1 << STRIPE_DEGRADED)),
4598                               head_sh->state & (1 << STRIPE_INSYNC));
4599
4600                 sh->check_state = head_sh->check_state;
4601                 sh->reconstruct_state = head_sh->reconstruct_state;
4602                 for (i = 0; i < sh->disks; i++) {
4603                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
4604                                 do_wakeup = 1;
4605                         sh->dev[i].flags = head_sh->dev[i].flags &
4606                                 (~((1 << R5_WriteError) | (1 << R5_Overlap)));
4607                 }
4608                 spin_lock_irq(&sh->stripe_lock);
4609                 sh->batch_head = NULL;
4610                 spin_unlock_irq(&sh->stripe_lock);
4611                 if (handle_flags == 0 ||
4612                     sh->state & handle_flags)
4613                         set_bit(STRIPE_HANDLE, &sh->state);
4614                 raid5_release_stripe(sh);
4615         }
4616         spin_lock_irq(&head_sh->stripe_lock);
4617         head_sh->batch_head = NULL;
4618         spin_unlock_irq(&head_sh->stripe_lock);
4619         for (i = 0; i < head_sh->disks; i++)
4620                 if (test_and_clear_bit(R5_Overlap, &head_sh->dev[i].flags))
4621                         do_wakeup = 1;
4622         if (head_sh->state & handle_flags)
4623                 set_bit(STRIPE_HANDLE, &head_sh->state);
4624
4625         if (do_wakeup)
4626                 wake_up(&head_sh->raid_conf->wait_for_overlap);
4627 }
4628
4629 static void handle_stripe(struct stripe_head *sh)
4630 {
4631         struct stripe_head_state s;
4632         struct r5conf *conf = sh->raid_conf;
4633         int i;
4634         int prexor;
4635         int disks = sh->disks;
4636         struct r5dev *pdev, *qdev;
4637
4638         clear_bit(STRIPE_HANDLE, &sh->state);
4639         if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
4640                 /* already being handled, ensure it gets handled
4641                  * again when current action finishes */
4642                 set_bit(STRIPE_HANDLE, &sh->state);
4643                 return;
4644         }
4645
4646         if (clear_batch_ready(sh) ) {
4647                 clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
4648                 return;
4649         }
4650
4651         if (test_and_clear_bit(STRIPE_BATCH_ERR, &sh->state))
4652                 break_stripe_batch_list(sh, 0);
4653
4654         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) && !sh->batch_head) {
4655                 spin_lock(&sh->stripe_lock);
4656                 /* Cannot process 'sync' concurrently with 'discard' */
4657                 if (!test_bit(STRIPE_DISCARD, &sh->state) &&
4658                     test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
4659                         set_bit(STRIPE_SYNCING, &sh->state);
4660                         clear_bit(STRIPE_INSYNC, &sh->state);
4661                         clear_bit(STRIPE_REPLACED, &sh->state);
4662                 }
4663                 spin_unlock(&sh->stripe_lock);
4664         }
4665         clear_bit(STRIPE_DELAYED, &sh->state);
4666
4667         pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
4668                 "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
4669                (unsigned long long)sh->sector, sh->state,
4670                atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
4671                sh->check_state, sh->reconstruct_state);
4672
4673         analyse_stripe(sh, &s);
4674
4675         if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
4676                 goto finish;
4677
4678         if (s.handle_bad_blocks ||
4679             test_bit(MD_SB_CHANGE_PENDING, &conf->mddev->sb_flags)) {
4680                 set_bit(STRIPE_HANDLE, &sh->state);
4681                 goto finish;
4682         }
4683
4684         if (unlikely(s.blocked_rdev)) {
4685                 if (s.syncing || s.expanding || s.expanded ||
4686                     s.replacing || s.to_write || s.written) {
4687                         set_bit(STRIPE_HANDLE, &sh->state);
4688                         goto finish;
4689                 }
4690                 /* There is nothing for the blocked_rdev to block */
4691                 rdev_dec_pending(s.blocked_rdev, conf->mddev);
4692                 s.blocked_rdev = NULL;
4693         }
4694
4695         if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
4696                 set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
4697                 set_bit(STRIPE_BIOFILL_RUN, &sh->state);
4698         }
4699
4700         pr_debug("locked=%d uptodate=%d to_read=%d"
4701                " to_write=%d failed=%d failed_num=%d,%d\n",
4702                s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
4703                s.failed_num[0], s.failed_num[1]);
4704         /* check if the array has lost more than max_degraded devices and,
4705          * if so, some requests might need to be failed.
4706          */
4707         if (s.failed > conf->max_degraded || s.log_failed) {
4708                 sh->check_state = 0;
4709                 sh->reconstruct_state = 0;
4710                 break_stripe_batch_list(sh, 0);
4711                 if (s.to_read+s.to_write+s.written)
4712                         handle_failed_stripe(conf, sh, &s, disks);
4713                 if (s.syncing + s.replacing)
4714                         handle_failed_sync(conf, sh, &s);
4715         }
4716
4717         /* Now we check to see if any write operations have recently
4718          * completed
4719          */
4720         prexor = 0;
4721         if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
4722                 prexor = 1;
4723         if (sh->reconstruct_state == reconstruct_state_drain_result ||
4724             sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
4725                 sh->reconstruct_state = reconstruct_state_idle;
4726
4727                 /* All the 'written' buffers and the parity block are ready to
4728                  * be written back to disk
4729                  */
4730                 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
4731                        !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
4732                 BUG_ON(sh->qd_idx >= 0 &&
4733                        !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
4734                        !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
4735                 for (i = disks; i--; ) {
4736                         struct r5dev *dev = &sh->dev[i];
4737                         if (test_bit(R5_LOCKED, &dev->flags) &&
4738                                 (i == sh->pd_idx || i == sh->qd_idx ||
4739                                  dev->written || test_bit(R5_InJournal,
4740                                                           &dev->flags))) {
4741                                 pr_debug("Writing block %d\n", i);
4742                                 set_bit(R5_Wantwrite, &dev->flags);
4743                                 if (prexor)
4744                                         continue;
4745                                 if (s.failed > 1)
4746                                         continue;
4747                                 if (!test_bit(R5_Insync, &dev->flags) ||
4748                                     ((i == sh->pd_idx || i == sh->qd_idx)  &&
4749                                      s.failed == 0))
4750                                         set_bit(STRIPE_INSYNC, &sh->state);
4751                         }
4752                 }
4753                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4754                         s.dec_preread_active = 1;
4755         }
4756
4757         /*
4758          * might be able to return some write requests if the parity blocks
4759          * are safe, or on a failed drive
4760          */
4761         pdev = &sh->dev[sh->pd_idx];
4762         s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
4763                 || (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
4764         qdev = &sh->dev[sh->qd_idx];
4765         s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
4766                 || (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
4767                 || conf->level < 6;
4768
4769         if (s.written &&
4770             (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
4771                              && !test_bit(R5_LOCKED, &pdev->flags)
4772                              && (test_bit(R5_UPTODATE, &pdev->flags) ||
4773                                  test_bit(R5_Discard, &pdev->flags))))) &&
4774             (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
4775                              && !test_bit(R5_LOCKED, &qdev->flags)
4776                              && (test_bit(R5_UPTODATE, &qdev->flags) ||
4777                                  test_bit(R5_Discard, &qdev->flags))))))
4778                 handle_stripe_clean_event(conf, sh, disks);
4779
4780         if (s.just_cached)
4781                 r5c_handle_cached_data_endio(conf, sh, disks);
4782         log_stripe_write_finished(sh);
4783
4784         /* Now we might consider reading some blocks, either to check/generate
4785          * parity, or to satisfy requests
4786          * or to load a block that is being partially written.
4787          */
4788         if (s.to_read || s.non_overwrite
4789             || (conf->level == 6 && s.to_write && s.failed)
4790             || (s.syncing && (s.uptodate + s.compute < disks))
4791             || s.replacing
4792             || s.expanding)
4793                 handle_stripe_fill(sh, &s, disks);
4794
4795         /*
4796          * When the stripe finishes full journal write cycle (write to journal
4797          * and raid disk), this is the clean up procedure so it is ready for
4798          * next operation.
4799          */
4800         r5c_finish_stripe_write_out(conf, sh, &s);
4801
4802         /*
4803          * Now to consider new write requests, cache write back and what else,
4804          * if anything should be read.  We do not handle new writes when:
4805          * 1/ A 'write' operation (copy+xor) is already in flight.
4806          * 2/ A 'check' operation is in flight, as it may clobber the parity
4807          *    block.
4808          * 3/ A r5c cache log write is in flight.
4809          */
4810
4811         if (!sh->reconstruct_state && !sh->check_state && !sh->log_io) {
4812                 if (!r5c_is_writeback(conf->log)) {
4813                         if (s.to_write)
4814                                 handle_stripe_dirtying(conf, sh, &s, disks);
4815                 } else { /* write back cache */
4816                         int ret = 0;
4817
4818                         /* First, try handle writes in caching phase */
4819                         if (s.to_write)
4820                                 ret = r5c_try_caching_write(conf, sh, &s,
4821                                                             disks);
4822                         /*
4823                          * If caching phase failed: ret == -EAGAIN
4824                          *    OR
4825                          * stripe under reclaim: !caching && injournal
4826                          *
4827                          * fall back to handle_stripe_dirtying()
4828                          */
4829                         if (ret == -EAGAIN ||
4830                             /* stripe under reclaim: !caching && injournal */
4831                             (!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
4832                              s.injournal > 0)) {
4833                                 ret = handle_stripe_dirtying(conf, sh, &s,
4834                                                              disks);
4835                                 if (ret == -EAGAIN)
4836                                         goto finish;
4837                         }
4838                 }
4839         }
4840
4841         /* maybe we need to check and possibly fix the parity for this stripe
4842          * Any reads will already have been scheduled, so we just see if enough
4843          * data is available.  The parity check is held off while parity
4844          * dependent operations are in flight.
4845          */
4846         if (sh->check_state ||
4847             (s.syncing && s.locked == 0 &&
4848              !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4849              !test_bit(STRIPE_INSYNC, &sh->state))) {
4850                 if (conf->level == 6)
4851                         handle_parity_checks6(conf, sh, &s, disks);
4852                 else
4853                         handle_parity_checks5(conf, sh, &s, disks);
4854         }
4855
4856         if ((s.replacing || s.syncing) && s.locked == 0
4857             && !test_bit(STRIPE_COMPUTE_RUN, &sh->state)
4858             && !test_bit(STRIPE_REPLACED, &sh->state)) {
4859                 /* Write out to replacement devices where possible */
4860                 for (i = 0; i < conf->raid_disks; i++)
4861                         if (test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
4862                                 WARN_ON(!test_bit(R5_UPTODATE, &sh->dev[i].flags));
4863                                 set_bit(R5_WantReplace, &sh->dev[i].flags);
4864                                 set_bit(R5_LOCKED, &sh->dev[i].flags);
4865                                 s.locked++;
4866                         }
4867                 if (s.replacing)
4868                         set_bit(STRIPE_INSYNC, &sh->state);
4869                 set_bit(STRIPE_REPLACED, &sh->state);
4870         }
4871         if ((s.syncing || s.replacing) && s.locked == 0 &&
4872             !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4873             test_bit(STRIPE_INSYNC, &sh->state)) {
4874                 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
4875                 clear_bit(STRIPE_SYNCING, &sh->state);
4876                 if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
4877                         wake_up(&conf->wait_for_overlap);
4878         }
4879
4880         /* If the failed drives are just a ReadError, then we might need
4881          * to progress the repair/check process
4882          */
4883         if (s.failed <= conf->max_degraded && !conf->mddev->ro)
4884                 for (i = 0; i < s.failed; i++) {
4885                         struct r5dev *dev = &sh->dev[s.failed_num[i]];
4886                         if (test_bit(R5_ReadError, &dev->flags)
4887                             && !test_bit(R5_LOCKED, &dev->flags)
4888                             && test_bit(R5_UPTODATE, &dev->flags)
4889                                 ) {
4890                                 if (!test_bit(R5_ReWrite, &dev->flags)) {
4891                                         set_bit(R5_Wantwrite, &dev->flags);
4892                                         set_bit(R5_ReWrite, &dev->flags);
4893                                         set_bit(R5_LOCKED, &dev->flags);
4894                                         s.locked++;
4895                                 } else {
4896                                         /* let's read it back */
4897                                         set_bit(R5_Wantread, &dev->flags);
4898                                         set_bit(R5_LOCKED, &dev->flags);
4899                                         s.locked++;
4900                                 }
4901                         }
4902                 }
4903
4904         /* Finish reconstruct operations initiated by the expansion process */
4905         if (sh->reconstruct_state == reconstruct_state_result) {
4906                 struct stripe_head *sh_src
4907                         = raid5_get_active_stripe(conf, sh->sector, 1, 1, 1);
4908                 if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
4909                         /* sh cannot be written until sh_src has been read.
4910                          * so arrange for sh to be delayed a little
4911                          */
4912                         set_bit(STRIPE_DELAYED, &sh->state);
4913                         set_bit(STRIPE_HANDLE, &sh->state);
4914                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
4915                                               &sh_src->state))
4916                                 atomic_inc(&conf->preread_active_stripes);
4917                         raid5_release_stripe(sh_src);
4918                         goto finish;
4919                 }
4920                 if (sh_src)
4921                         raid5_release_stripe(sh_src);
4922
4923                 sh->reconstruct_state = reconstruct_state_idle;
4924                 clear_bit(STRIPE_EXPANDING, &sh->state);
4925                 for (i = conf->raid_disks; i--; ) {
4926                         set_bit(R5_Wantwrite, &sh->dev[i].flags);
4927                         set_bit(R5_LOCKED, &sh->dev[i].flags);
4928                         s.locked++;
4929                 }
4930         }
4931
4932         if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
4933             !sh->reconstruct_state) {
4934                 /* Need to write out all blocks after computing parity */
4935                 sh->disks = conf->raid_disks;
4936                 stripe_set_idx(sh->sector, conf, 0, sh);
4937                 schedule_reconstruction(sh, &s, 1, 1);
4938         } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
4939                 clear_bit(STRIPE_EXPAND_READY, &sh->state);
4940                 atomic_dec(&conf->reshape_stripes);
4941                 wake_up(&conf->wait_for_overlap);
4942                 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
4943         }
4944
4945         if (s.expanding && s.locked == 0 &&
4946             !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
4947                 handle_stripe_expansion(conf, sh);
4948
4949 finish:
4950         /* wait for this device to become unblocked */
4951         if (unlikely(s.blocked_rdev)) {
4952                 if (conf->mddev->external)
4953                         md_wait_for_blocked_rdev(s.blocked_rdev,
4954                                                  conf->mddev);
4955                 else
4956                         /* Internal metadata will immediately
4957                          * be written by raid5d, so we don't
4958                          * need to wait here.
4959                          */
4960                         rdev_dec_pending(s.blocked_rdev,
4961                                          conf->mddev);
4962         }
4963
4964         if (s.handle_bad_blocks)
4965                 for (i = disks; i--; ) {
4966                         struct md_rdev *rdev;
4967                         struct r5dev *dev = &sh->dev[i];
4968                         if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
4969                                 /* We own a safe reference to the rdev */
4970                                 rdev = conf->disks[i].rdev;
4971                                 if (!rdev_set_badblocks(rdev, sh->sector,
4972                                                         STRIPE_SECTORS, 0))
4973                                         md_error(conf->mddev, rdev);
4974                                 rdev_dec_pending(rdev, conf->mddev);
4975                         }
4976                         if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
4977                                 rdev = conf->disks[i].rdev;
4978                                 rdev_clear_badblocks(rdev, sh->sector,
4979                                                      STRIPE_SECTORS, 0);
4980                                 rdev_dec_pending(rdev, conf->mddev);
4981                         }
4982                         if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
4983                                 rdev = conf->disks[i].replacement;
4984                                 if (!rdev)
4985                                         /* rdev have been moved down */
4986                                         rdev = conf->disks[i].rdev;
4987                                 rdev_clear_badblocks(rdev, sh->sector,
4988                                                      STRIPE_SECTORS, 0);
4989                                 rdev_dec_pending(rdev, conf->mddev);
4990                         }
4991                 }
4992
4993         if (s.ops_request)
4994                 raid_run_ops(sh, s.ops_request);
4995
4996         ops_run_io(sh, &s);
4997
4998         if (s.dec_preread_active) {
4999                 /* We delay this until after ops_run_io so that if make_request
5000                  * is waiting on a flush, it won't continue until the writes
5001                  * have actually been submitted.
5002                  */
5003                 atomic_dec(&conf->preread_active_stripes);
5004                 if (atomic_read(&conf->preread_active_stripes) <
5005                     IO_THRESHOLD)
5006                         md_wakeup_thread(conf->mddev->thread);
5007         }
5008
5009         clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
5010 }
5011
5012 static void raid5_activate_delayed(struct r5conf *conf)
5013 {
5014         if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
5015                 while (!list_empty(&conf->delayed_list)) {
5016                         struct list_head *l = conf->delayed_list.next;
5017                         struct stripe_head *sh;
5018                         sh = list_entry(l, struct stripe_head, lru);
5019                         list_del_init(l);
5020                         clear_bit(STRIPE_DELAYED, &sh->state);
5021                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5022                                 atomic_inc(&conf->preread_active_stripes);
5023                         list_add_tail(&sh->lru, &conf->hold_list);
5024                         raid5_wakeup_stripe_thread(sh);
5025                 }
5026         }
5027 }
5028
5029 static void activate_bit_delay(struct r5conf *conf,
5030         struct list_head *temp_inactive_list)
5031 {
5032         /* device_lock is held */
5033         struct list_head head;
5034         list_add(&head, &conf->bitmap_list);
5035         list_del_init(&conf->bitmap_list);
5036         while (!list_empty(&head)) {
5037                 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
5038                 int hash;
5039                 list_del_init(&sh->lru);
5040                 atomic_inc(&sh->count);
5041                 hash = sh->hash_lock_index;
5042                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
5043         }
5044 }
5045
5046 static int raid5_congested(struct mddev *mddev, int bits)
5047 {
5048         struct r5conf *conf = mddev->private;
5049
5050         /* No difference between reads and writes.  Just check
5051          * how busy the stripe_cache is
5052          */
5053
5054         if (test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
5055                 return 1;
5056
5057         /* Also checks whether there is pressure on r5cache log space */
5058         if (test_bit(R5C_LOG_TIGHT, &conf->cache_state))
5059                 return 1;
5060         if (conf->quiesce)
5061                 return 1;
5062         if (atomic_read(&conf->empty_inactive_list_nr))
5063                 return 1;
5064
5065         return 0;
5066 }
5067
5068 static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
5069 {
5070         struct r5conf *conf = mddev->private;
5071         sector_t sector = bio->bi_iter.bi_sector + get_start_sect(bio->bi_bdev);
5072         unsigned int chunk_sectors;
5073         unsigned int bio_sectors = bio_sectors(bio);
5074
5075         chunk_sectors = min(conf->chunk_sectors, conf->prev_chunk_sectors);
5076         return  chunk_sectors >=
5077                 ((sector & (chunk_sectors - 1)) + bio_sectors);
5078 }
5079
5080 /*
5081  *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
5082  *  later sampled by raid5d.
5083  */
5084 static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
5085 {
5086         unsigned long flags;
5087
5088         spin_lock_irqsave(&conf->device_lock, flags);
5089
5090         bi->bi_next = conf->retry_read_aligned_list;
5091         conf->retry_read_aligned_list = bi;
5092
5093         spin_unlock_irqrestore(&conf->device_lock, flags);
5094         md_wakeup_thread(conf->mddev->thread);
5095 }
5096
5097 static struct bio *remove_bio_from_retry(struct r5conf *conf,
5098                                          unsigned int *offset)
5099 {
5100         struct bio *bi;
5101
5102         bi = conf->retry_read_aligned;
5103         if (bi) {
5104                 *offset = conf->retry_read_offset;
5105                 conf->retry_read_aligned = NULL;
5106                 return bi;
5107         }
5108         bi = conf->retry_read_aligned_list;
5109         if(bi) {
5110                 conf->retry_read_aligned_list = bi->bi_next;
5111                 bi->bi_next = NULL;
5112                 *offset = 0;
5113         }
5114
5115         return bi;
5116 }
5117
5118 /*
5119  *  The "raid5_align_endio" should check if the read succeeded and if it
5120  *  did, call bio_endio on the original bio (having bio_put the new bio
5121  *  first).
5122  *  If the read failed..
5123  */
5124 static void raid5_align_endio(struct bio *bi)
5125 {
5126         struct bio* raid_bi  = bi->bi_private;
5127         struct mddev *mddev;
5128         struct r5conf *conf;
5129         struct md_rdev *rdev;
5130         int error = bi->bi_error;
5131
5132         bio_put(bi);
5133
5134         rdev = (void*)raid_bi->bi_next;
5135         raid_bi->bi_next = NULL;
5136         mddev = rdev->mddev;
5137         conf = mddev->private;
5138
5139         rdev_dec_pending(rdev, conf->mddev);
5140
5141         if (!error) {
5142                 bio_endio(raid_bi);
5143                 if (atomic_dec_and_test(&conf->active_aligned_reads))
5144                         wake_up(&conf->wait_for_quiescent);
5145                 return;
5146         }
5147
5148         pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
5149
5150         add_bio_to_retry(raid_bi, conf);
5151 }
5152
5153 static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
5154 {
5155         struct r5conf *conf = mddev->private;
5156         int dd_idx;
5157         struct bio* align_bi;
5158         struct md_rdev *rdev;
5159         sector_t end_sector;
5160
5161         if (!in_chunk_boundary(mddev, raid_bio)) {
5162                 pr_debug("%s: non aligned\n", __func__);
5163                 return 0;
5164         }
5165         /*
5166          * use bio_clone_fast to make a copy of the bio
5167          */
5168         align_bi = bio_clone_fast(raid_bio, GFP_NOIO, mddev->bio_set);
5169         if (!align_bi)
5170                 return 0;
5171         /*
5172          *   set bi_end_io to a new function, and set bi_private to the
5173          *     original bio.
5174          */
5175         align_bi->bi_end_io  = raid5_align_endio;
5176         align_bi->bi_private = raid_bio;
5177         /*
5178          *      compute position
5179          */
5180         align_bi->bi_iter.bi_sector =
5181                 raid5_compute_sector(conf, raid_bio->bi_iter.bi_sector,
5182                                      0, &dd_idx, NULL);
5183
5184         end_sector = bio_end_sector(align_bi);
5185         rcu_read_lock();
5186         rdev = rcu_dereference(conf->disks[dd_idx].replacement);
5187         if (!rdev || test_bit(Faulty, &rdev->flags) ||
5188             rdev->recovery_offset < end_sector) {
5189                 rdev = rcu_dereference(conf->disks[dd_idx].rdev);
5190                 if (rdev &&
5191                     (test_bit(Faulty, &rdev->flags) ||
5192                     !(test_bit(In_sync, &rdev->flags) ||
5193                       rdev->recovery_offset >= end_sector)))
5194                         rdev = NULL;
5195         }
5196
5197         if (r5c_big_stripe_cached(conf, align_bi->bi_iter.bi_sector)) {
5198                 rcu_read_unlock();
5199                 bio_put(align_bi);
5200                 return 0;
5201         }
5202
5203         if (rdev) {
5204                 sector_t first_bad;
5205                 int bad_sectors;
5206
5207                 atomic_inc(&rdev->nr_pending);
5208                 rcu_read_unlock();
5209                 raid_bio->bi_next = (void*)rdev;
5210                 align_bi->bi_bdev =  rdev->bdev;
5211                 bio_clear_flag(align_bi, BIO_SEG_VALID);
5212
5213                 if (is_badblock(rdev, align_bi->bi_iter.bi_sector,
5214                                 bio_sectors(align_bi),
5215                                 &first_bad, &bad_sectors)) {
5216                         bio_put(align_bi);
5217                         rdev_dec_pending(rdev, mddev);
5218                         return 0;
5219                 }
5220
5221                 /* No reshape active, so we can trust rdev->data_offset */
5222                 align_bi->bi_iter.bi_sector += rdev->data_offset;
5223
5224                 spin_lock_irq(&conf->device_lock);
5225                 wait_event_lock_irq(conf->wait_for_quiescent,
5226                                     conf->quiesce == 0,
5227                                     conf->device_lock);
5228                 atomic_inc(&conf->active_aligned_reads);
5229                 spin_unlock_irq(&conf->device_lock);
5230
5231                 if (mddev->gendisk)
5232                         trace_block_bio_remap(bdev_get_queue(align_bi->bi_bdev),
5233                                               align_bi, disk_devt(mddev->gendisk),
5234                                               raid_bio->bi_iter.bi_sector);
5235                 generic_make_request(align_bi);
5236                 return 1;
5237         } else {
5238                 rcu_read_unlock();
5239                 bio_put(align_bi);
5240                 return 0;
5241         }
5242 }
5243
5244 static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
5245 {
5246         struct bio *split;
5247         sector_t sector = raid_bio->bi_iter.bi_sector;
5248         unsigned chunk_sects = mddev->chunk_sectors;
5249         unsigned sectors = chunk_sects - (sector & (chunk_sects-1));
5250
5251         if (sectors < bio_sectors(raid_bio)) {
5252                 struct r5conf *conf = mddev->private;
5253                 split = bio_split(raid_bio, sectors, GFP_NOIO, conf->bio_split);
5254                 bio_chain(split, raid_bio);
5255                 generic_make_request(raid_bio);
5256                 raid_bio = split;
5257         }
5258
5259         if (!raid5_read_one_chunk(mddev, raid_bio))
5260                 return raid_bio;
5261
5262         return NULL;
5263 }
5264
5265 /* __get_priority_stripe - get the next stripe to process
5266  *
5267  * Full stripe writes are allowed to pass preread active stripes up until
5268  * the bypass_threshold is exceeded.  In general the bypass_count
5269  * increments when the handle_list is handled before the hold_list; however, it
5270  * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
5271  * stripe with in flight i/o.  The bypass_count will be reset when the
5272  * head of the hold_list has changed, i.e. the head was promoted to the
5273  * handle_list.
5274  */
5275 static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group)
5276 {
5277         struct stripe_head *sh, *tmp;
5278         struct list_head *handle_list = NULL;
5279         struct r5worker_group *wg;
5280         bool second_try = !r5c_is_writeback(conf->log);
5281         bool try_loprio = test_bit(R5C_LOG_TIGHT, &conf->cache_state);
5282
5283 again:
5284         wg = NULL;
5285         sh = NULL;
5286         if (conf->worker_cnt_per_group == 0) {
5287                 handle_list = try_loprio ? &conf->loprio_list :
5288                                         &conf->handle_list;
5289         } else if (group != ANY_GROUP) {
5290                 handle_list = try_loprio ? &conf->worker_groups[group].loprio_list :
5291                                 &conf->worker_groups[group].handle_list;
5292                 wg = &conf->worker_groups[group];
5293         } else {
5294                 int i;
5295                 for (i = 0; i < conf->group_cnt; i++) {
5296                         handle_list = try_loprio ? &conf->worker_groups[i].loprio_list :
5297                                 &conf->worker_groups[i].handle_list;
5298                         wg = &conf->worker_groups[i];
5299                         if (!list_empty(handle_list))
5300                                 break;
5301                 }
5302         }
5303
5304         pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
5305                   __func__,
5306                   list_empty(handle_list) ? "empty" : "busy",
5307                   list_empty(&conf->hold_list) ? "empty" : "busy",
5308                   atomic_read(&conf->pending_full_writes), conf->bypass_count);
5309
5310         if (!list_empty(handle_list)) {
5311                 sh = list_entry(handle_list->next, typeof(*sh), lru);
5312
5313                 if (list_empty(&conf->hold_list))
5314                         conf->bypass_count = 0;
5315                 else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
5316                         if (conf->hold_list.next == conf->last_hold)
5317                                 conf->bypass_count++;
5318                         else {
5319                                 conf->last_hold = conf->hold_list.next;
5320                                 conf->bypass_count -= conf->bypass_threshold;
5321                                 if (conf->bypass_count < 0)
5322                                         conf->bypass_count = 0;
5323                         }
5324                 }
5325         } else if (!list_empty(&conf->hold_list) &&
5326                    ((conf->bypass_threshold &&
5327                      conf->bypass_count > conf->bypass_threshold) ||
5328                     atomic_read(&conf->pending_full_writes) == 0)) {
5329
5330                 list_for_each_entry(tmp, &conf->hold_list,  lru) {
5331                         if (conf->worker_cnt_per_group == 0 ||
5332                             group == ANY_GROUP ||
5333                             !cpu_online(tmp->cpu) ||
5334                             cpu_to_group(tmp->cpu) == group) {
5335                                 sh = tmp;
5336                                 break;
5337                         }
5338                 }
5339
5340                 if (sh) {
5341                         conf->bypass_count -= conf->bypass_threshold;
5342                         if (conf->bypass_count < 0)
5343                                 conf->bypass_count = 0;
5344                 }
5345                 wg = NULL;
5346         }
5347
5348         if (!sh) {
5349                 if (second_try)
5350                         return NULL;
5351                 second_try = true;
5352                 try_loprio = !try_loprio;
5353                 goto again;
5354         }
5355
5356         if (wg) {
5357                 wg->stripes_cnt--;
5358                 sh->group = NULL;
5359         }
5360         list_del_init(&sh->lru);
5361         BUG_ON(atomic_inc_return(&sh->count) != 1);
5362         return sh;
5363 }
5364
5365 struct raid5_plug_cb {
5366         struct blk_plug_cb      cb;
5367         struct list_head        list;
5368         struct list_head        temp_inactive_list[NR_STRIPE_HASH_LOCKS];
5369 };
5370
5371 static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
5372 {
5373         struct raid5_plug_cb *cb = container_of(
5374                 blk_cb, struct raid5_plug_cb, cb);
5375         struct stripe_head *sh;
5376         struct mddev *mddev = cb->cb.data;
5377         struct r5conf *conf = mddev->private;
5378         int cnt = 0;
5379         int hash;
5380
5381         if (cb->list.next && !list_empty(&cb->list)) {
5382                 spin_lock_irq(&conf->device_lock);
5383                 while (!list_empty(&cb->list)) {
5384                         sh = list_first_entry(&cb->list, struct stripe_head, lru);
5385                         list_del_init(&sh->lru);
5386                         /*
5387                          * avoid race release_stripe_plug() sees
5388                          * STRIPE_ON_UNPLUG_LIST clear but the stripe
5389                          * is still in our list
5390                          */
5391                         smp_mb__before_atomic();
5392                         clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
5393                         /*
5394                          * STRIPE_ON_RELEASE_LIST could be set here. In that
5395                          * case, the count is always > 1 here
5396                          */
5397                         hash = sh->hash_lock_index;
5398                         __release_stripe(conf, sh, &cb->temp_inactive_list[hash]);
5399                         cnt++;
5400                 }
5401                 spin_unlock_irq(&conf->device_lock);
5402         }
5403         release_inactive_stripe_list(conf, cb->temp_inactive_list,
5404                                      NR_STRIPE_HASH_LOCKS);
5405         if (mddev->queue)
5406                 trace_block_unplug(mddev->queue, cnt, !from_schedule);
5407         kfree(cb);
5408 }
5409
5410 static void release_stripe_plug(struct mddev *mddev,
5411                                 struct stripe_head *sh)
5412 {
5413         struct blk_plug_cb *blk_cb = blk_check_plugged(
5414                 raid5_unplug, mddev,
5415                 sizeof(struct raid5_plug_cb));
5416         struct raid5_plug_cb *cb;
5417
5418         if (!blk_cb) {
5419                 raid5_release_stripe(sh);
5420                 return;
5421         }
5422
5423         cb = container_of(blk_cb, struct raid5_plug_cb, cb);
5424
5425         if (cb->list.next == NULL) {
5426                 int i;
5427                 INIT_LIST_HEAD(&cb->list);
5428                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
5429                         INIT_LIST_HEAD(cb->temp_inactive_list + i);
5430         }
5431
5432         if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
5433                 list_add_tail(&sh->lru, &cb->list);
5434         else
5435                 raid5_release_stripe(sh);
5436 }
5437
5438 static void make_discard_request(struct mddev *mddev, struct bio *bi)
5439 {
5440         struct r5conf *conf = mddev->private;
5441         sector_t logical_sector, last_sector;
5442         struct stripe_head *sh;
5443         int stripe_sectors;
5444
5445         if (mddev->reshape_position != MaxSector)
5446                 /* Skip discard while reshape is happening */
5447                 return;
5448
5449         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
5450         last_sector = bi->bi_iter.bi_sector + (bi->bi_iter.bi_size>>9);
5451
5452         bi->bi_next = NULL;
5453         md_write_start(mddev, bi);
5454
5455         stripe_sectors = conf->chunk_sectors *
5456                 (conf->raid_disks - conf->max_degraded);
5457         logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
5458                                                stripe_sectors);
5459         sector_div(last_sector, stripe_sectors);
5460
5461         logical_sector *= conf->chunk_sectors;
5462         last_sector *= conf->chunk_sectors;
5463
5464         for (; logical_sector < last_sector;
5465              logical_sector += STRIPE_SECTORS) {
5466                 DEFINE_WAIT(w);
5467                 int d;
5468         again:
5469                 sh = raid5_get_active_stripe(conf, logical_sector, 0, 0, 0);
5470                 prepare_to_wait(&conf->wait_for_overlap, &w,
5471                                 TASK_UNINTERRUPTIBLE);
5472                 set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5473                 if (test_bit(STRIPE_SYNCING, &sh->state)) {
5474                         raid5_release_stripe(sh);
5475                         schedule();
5476                         goto again;
5477                 }
5478                 clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5479                 spin_lock_irq(&sh->stripe_lock);
5480                 for (d = 0; d < conf->raid_disks; d++) {
5481                         if (d == sh->pd_idx || d == sh->qd_idx)
5482                                 continue;
5483                         if (sh->dev[d].towrite || sh->dev[d].toread) {
5484                                 set_bit(R5_Overlap, &sh->dev[d].flags);
5485                                 spin_unlock_irq(&sh->stripe_lock);
5486                                 raid5_release_stripe(sh);
5487                                 schedule();
5488                                 goto again;
5489                         }
5490                 }
5491                 set_bit(STRIPE_DISCARD, &sh->state);
5492                 finish_wait(&conf->wait_for_overlap, &w);
5493                 sh->overwrite_disks = 0;
5494                 for (d = 0; d < conf->raid_disks; d++) {
5495                         if (d == sh->pd_idx || d == sh->qd_idx)
5496                                 continue;
5497                         sh->dev[d].towrite = bi;
5498                         set_bit(R5_OVERWRITE, &sh->dev[d].flags);
5499                         bio_inc_remaining(bi);
5500                         md_write_inc(mddev, bi);
5501                         sh->overwrite_disks++;
5502                 }
5503                 spin_unlock_irq(&sh->stripe_lock);
5504                 if (conf->mddev->bitmap) {
5505                         for (d = 0;
5506                              d < conf->raid_disks - conf->max_degraded;
5507                              d++)
5508                                 bitmap_startwrite(mddev->bitmap,
5509                                                   sh->sector,
5510                                                   STRIPE_SECTORS,
5511                                                   0);
5512                         sh->bm_seq = conf->seq_flush + 1;
5513                         set_bit(STRIPE_BIT_DELAY, &sh->state);
5514                 }
5515
5516                 set_bit(STRIPE_HANDLE, &sh->state);
5517                 clear_bit(STRIPE_DELAYED, &sh->state);
5518                 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5519                         atomic_inc(&conf->preread_active_stripes);
5520                 release_stripe_plug(mddev, sh);
5521         }
5522
5523         md_write_end(mddev);
5524         bio_endio(bi);
5525 }
5526
5527 static void raid5_make_request(struct mddev *mddev, struct bio * bi)
5528 {
5529         struct r5conf *conf = mddev->private;
5530         int dd_idx;
5531         sector_t new_sector;
5532         sector_t logical_sector, last_sector;
5533         struct stripe_head *sh;
5534         const int rw = bio_data_dir(bi);
5535         DEFINE_WAIT(w);
5536         bool do_prepare;
5537         bool do_flush = false;
5538
5539         if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
5540                 int ret = r5l_handle_flush_request(conf->log, bi);
5541
5542                 if (ret == 0)
5543                         return;
5544                 if (ret == -ENODEV) {
5545                         md_flush_request(mddev, bi);
5546                         return;
5547                 }
5548                 /* ret == -EAGAIN, fallback */
5549                 /*
5550                  * if r5l_handle_flush_request() didn't clear REQ_PREFLUSH,
5551                  * we need to flush journal device
5552                  */
5553                 do_flush = bi->bi_opf & REQ_PREFLUSH;
5554         }
5555
5556         /*
5557          * If array is degraded, better not do chunk aligned read because
5558          * later we might have to read it again in order to reconstruct
5559          * data on failed drives.
5560          */
5561         if (rw == READ && mddev->degraded == 0 &&
5562             mddev->reshape_position == MaxSector) {
5563                 bi = chunk_aligned_read(mddev, bi);
5564                 if (!bi)
5565                         return;
5566         }
5567
5568         if (unlikely(bio_op(bi) == REQ_OP_DISCARD)) {
5569                 make_discard_request(mddev, bi);
5570                 return;
5571         }
5572
5573         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
5574         last_sector = bio_end_sector(bi);
5575         bi->bi_next = NULL;
5576         md_write_start(mddev, bi);
5577
5578         prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
5579         for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
5580                 int previous;
5581                 int seq;
5582
5583                 do_prepare = false;
5584         retry:
5585                 seq = read_seqcount_begin(&conf->gen_lock);
5586                 previous = 0;
5587                 if (do_prepare)
5588                         prepare_to_wait(&conf->wait_for_overlap, &w,
5589                                 TASK_UNINTERRUPTIBLE);
5590                 if (unlikely(conf->reshape_progress != MaxSector)) {
5591                         /* spinlock is needed as reshape_progress may be
5592                          * 64bit on a 32bit platform, and so it might be
5593                          * possible to see a half-updated value
5594                          * Of course reshape_progress could change after
5595                          * the lock is dropped, so once we get a reference
5596                          * to the stripe that we think it is, we will have
5597                          * to check again.
5598                          */
5599                         spin_lock_irq(&conf->device_lock);
5600                         if (mddev->reshape_backwards
5601                             ? logical_sector < conf->reshape_progress
5602                             : logical_sector >= conf->reshape_progress) {
5603                                 previous = 1;
5604                         } else {
5605                                 if (mddev->reshape_backwards
5606                                     ? logical_sector < conf->reshape_safe
5607                                     : logical_sector >= conf->reshape_safe) {
5608                                         spin_unlock_irq(&conf->device_lock);
5609                                         schedule();
5610                                         do_prepare = true;
5611                                         goto retry;
5612                                 }
5613                         }
5614                         spin_unlock_irq(&conf->device_lock);
5615                 }
5616
5617                 new_sector = raid5_compute_sector(conf, logical_sector,
5618                                                   previous,
5619                                                   &dd_idx, NULL);
5620                 pr_debug("raid456: raid5_make_request, sector %llu logical %llu\n",
5621                         (unsigned long long)new_sector,
5622                         (unsigned long long)logical_sector);
5623
5624                 sh = raid5_get_active_stripe(conf, new_sector, previous,
5625                                        (bi->bi_opf & REQ_RAHEAD), 0);
5626                 if (sh) {
5627                         if (unlikely(previous)) {
5628                                 /* expansion might have moved on while waiting for a
5629                                  * stripe, so we must do the range check again.
5630                                  * Expansion could still move past after this
5631                                  * test, but as we are holding a reference to
5632                                  * 'sh', we know that if that happens,
5633                                  *  STRIPE_EXPANDING will get set and the expansion
5634                                  * won't proceed until we finish with the stripe.
5635                                  */
5636                                 int must_retry = 0;
5637                                 spin_lock_irq(&conf->device_lock);
5638                                 if (mddev->reshape_backwards
5639                                     ? logical_sector >= conf->reshape_progress
5640                                     : logical_sector < conf->reshape_progress)
5641                                         /* mismatch, need to try again */
5642                                         must_retry = 1;
5643                                 spin_unlock_irq(&conf->device_lock);
5644                                 if (must_retry) {
5645                                         raid5_release_stripe(sh);
5646                                         schedule();
5647                                         do_prepare = true;
5648                                         goto retry;
5649                                 }
5650                         }
5651                         if (read_seqcount_retry(&conf->gen_lock, seq)) {
5652                                 /* Might have got the wrong stripe_head
5653                                  * by accident
5654                                  */
5655                                 raid5_release_stripe(sh);
5656                                 goto retry;
5657                         }
5658
5659                         if (rw == WRITE &&
5660                             logical_sector >= mddev->suspend_lo &&
5661                             logical_sector < mddev->suspend_hi) {
5662                                 raid5_release_stripe(sh);
5663                                 /* As the suspend_* range is controlled by
5664                                  * userspace, we want an interruptible
5665                                  * wait.
5666                                  */
5667                                 flush_signals(current);
5668                                 prepare_to_wait(&conf->wait_for_overlap,
5669                                                 &w, TASK_INTERRUPTIBLE);
5670                                 if (logical_sector >= mddev->suspend_lo &&
5671                                     logical_sector < mddev->suspend_hi) {
5672                                         schedule();
5673                                         do_prepare = true;
5674                                 }
5675                                 goto retry;
5676                         }
5677
5678                         if (test_bit(STRIPE_EXPANDING, &sh->state) ||
5679                             !add_stripe_bio(sh, bi, dd_idx, rw, previous)) {
5680                                 /* Stripe is busy expanding or
5681                                  * add failed due to overlap.  Flush everything
5682                                  * and wait a while
5683                                  */
5684                                 md_wakeup_thread(mddev->thread);
5685                                 raid5_release_stripe(sh);
5686                                 schedule();
5687                                 do_prepare = true;
5688                                 goto retry;
5689                         }
5690                         if (do_flush) {
5691                                 set_bit(STRIPE_R5C_PREFLUSH, &sh->state);
5692                                 /* we only need flush for one stripe */
5693                                 do_flush = false;
5694                         }
5695
5696                         set_bit(STRIPE_HANDLE, &sh->state);
5697                         clear_bit(STRIPE_DELAYED, &sh->state);
5698                         if ((!sh->batch_head || sh == sh->batch_head) &&
5699                             (bi->bi_opf & REQ_SYNC) &&
5700                             !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5701                                 atomic_inc(&conf->preread_active_stripes);
5702                         release_stripe_plug(mddev, sh);
5703                 } else {
5704                         /* cannot get stripe for read-ahead, just give-up */
5705                         bi->bi_error = -EIO;
5706                         break;
5707                 }
5708         }
5709         finish_wait(&conf->wait_for_overlap, &w);
5710
5711         if (rw == WRITE)
5712                 md_write_end(mddev);
5713         bio_endio(bi);
5714 }
5715
5716 static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
5717
5718 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
5719 {
5720         /* reshaping is quite different to recovery/resync so it is
5721          * handled quite separately ... here.
5722          *
5723          * On each call to sync_request, we gather one chunk worth of
5724          * destination stripes and flag them as expanding.
5725          * Then we find all the source stripes and request reads.
5726          * As the reads complete, handle_stripe will copy the data
5727          * into the destination stripe and release that stripe.
5728          */
5729         struct r5conf *conf = mddev->private;
5730         struct stripe_head *sh;
5731         sector_t first_sector, last_sector;
5732         int raid_disks = conf->previous_raid_disks;
5733         int data_disks = raid_disks - conf->max_degraded;
5734         int new_data_disks = conf->raid_disks - conf->max_degraded;
5735         int i;
5736         int dd_idx;
5737         sector_t writepos, readpos, safepos;
5738         sector_t stripe_addr;
5739         int reshape_sectors;
5740         struct list_head stripes;
5741         sector_t retn;
5742
5743         if (sector_nr == 0) {
5744                 /* If restarting in the middle, skip the initial sectors */
5745                 if (mddev->reshape_backwards &&
5746                     conf->reshape_progress < raid5_size(mddev, 0, 0)) {
5747                         sector_nr = raid5_size(mddev, 0, 0)
5748                                 - conf->reshape_progress;
5749                 } else if (mddev->reshape_backwards &&
5750                            conf->reshape_progress == MaxSector) {
5751                         /* shouldn't happen, but just in case, finish up.*/
5752                         sector_nr = MaxSector;
5753                 } else if (!mddev->reshape_backwards &&
5754                            conf->reshape_progress > 0)
5755                         sector_nr = conf->reshape_progress;
5756                 sector_div(sector_nr, new_data_disks);
5757                 if (sector_nr) {
5758                         mddev->curr_resync_completed = sector_nr;
5759                         sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5760                         *skipped = 1;
5761                         retn = sector_nr;
5762                         goto finish;
5763                 }
5764         }
5765
5766         /* We need to process a full chunk at a time.
5767          * If old and new chunk sizes differ, we need to process the
5768          * largest of these
5769          */
5770
5771         reshape_sectors = max(conf->chunk_sectors, conf->prev_chunk_sectors);
5772
5773         /* We update the metadata at least every 10 seconds, or when
5774          * the data about to be copied would over-write the source of
5775          * the data at the front of the range.  i.e. one new_stripe
5776          * along from reshape_progress new_maps to after where
5777          * reshape_safe old_maps to
5778          */
5779         writepos = conf->reshape_progress;
5780         sector_div(writepos, new_data_disks);
5781         readpos = conf->reshape_progress;
5782         sector_div(readpos, data_disks);
5783         safepos = conf->reshape_safe;
5784         sector_div(safepos, data_disks);
5785         if (mddev->reshape_backwards) {
5786                 BUG_ON(writepos < reshape_sectors);
5787                 writepos -= reshape_sectors;
5788                 readpos += reshape_sectors;
5789                 safepos += reshape_sectors;
5790         } else {
5791                 writepos += reshape_sectors;
5792                 /* readpos and safepos are worst-case calculations.
5793                  * A negative number is overly pessimistic, and causes
5794                  * obvious problems for unsigned storage.  So clip to 0.
5795                  */
5796                 readpos -= min_t(sector_t, reshape_sectors, readpos);
5797                 safepos -= min_t(sector_t, reshape_sectors, safepos);
5798         }
5799
5800         /* Having calculated the 'writepos' possibly use it
5801          * to set 'stripe_addr' which is where we will write to.
5802          */
5803         if (mddev->reshape_backwards) {
5804                 BUG_ON(conf->reshape_progress == 0);
5805                 stripe_addr = writepos;
5806                 BUG_ON((mddev->dev_sectors &
5807                         ~((sector_t)reshape_sectors - 1))
5808                        - reshape_sectors - stripe_addr
5809                        != sector_nr);
5810         } else {
5811                 BUG_ON(writepos != sector_nr + reshape_sectors);
5812                 stripe_addr = sector_nr;
5813         }
5814
5815         /* 'writepos' is the most advanced device address we might write.
5816          * 'readpos' is the least advanced device address we might read.
5817          * 'safepos' is the least address recorded in the metadata as having
5818          *     been reshaped.
5819          * If there is a min_offset_diff, these are adjusted either by
5820          * increasing the safepos/readpos if diff is negative, or
5821          * increasing writepos if diff is positive.
5822          * If 'readpos' is then behind 'writepos', there is no way that we can
5823          * ensure safety in the face of a crash - that must be done by userspace
5824          * making a backup of the data.  So in that case there is no particular
5825          * rush to update metadata.
5826          * Otherwise if 'safepos' is behind 'writepos', then we really need to
5827          * update the metadata to advance 'safepos' to match 'readpos' so that
5828          * we can be safe in the event of a crash.
5829          * So we insist on updating metadata if safepos is behind writepos and
5830          * readpos is beyond writepos.
5831          * In any case, update the metadata every 10 seconds.
5832          * Maybe that number should be configurable, but I'm not sure it is
5833          * worth it.... maybe it could be a multiple of safemode_delay???
5834          */
5835         if (conf->min_offset_diff < 0) {
5836                 safepos += -conf->min_offset_diff;
5837                 readpos += -conf->min_offset_diff;
5838         } else
5839                 writepos += conf->min_offset_diff;
5840
5841         if ((mddev->reshape_backwards
5842              ? (safepos > writepos && readpos < writepos)
5843              : (safepos < writepos && readpos > writepos)) ||
5844             time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
5845                 /* Cannot proceed until we've updated the superblock... */
5846                 wait_event(conf->wait_for_overlap,
5847                            atomic_read(&conf->reshape_stripes)==0
5848                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5849                 if (atomic_read(&conf->reshape_stripes) != 0)
5850                         return 0;
5851                 mddev->reshape_position = conf->reshape_progress;
5852                 mddev->curr_resync_completed = sector_nr;
5853                 conf->reshape_checkpoint = jiffies;
5854                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
5855                 md_wakeup_thread(mddev->thread);
5856                 wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
5857                            test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5858                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5859                         return 0;
5860                 spin_lock_irq(&conf->device_lock);
5861                 conf->reshape_safe = mddev->reshape_position;
5862                 spin_unlock_irq(&conf->device_lock);
5863                 wake_up(&conf->wait_for_overlap);
5864                 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5865         }
5866
5867         INIT_LIST_HEAD(&stripes);
5868         for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
5869                 int j;
5870                 int skipped_disk = 0;
5871                 sh = raid5_get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
5872                 set_bit(STRIPE_EXPANDING, &sh->state);
5873                 atomic_inc(&conf->reshape_stripes);
5874                 /* If any of this stripe is beyond the end of the old
5875                  * array, then we need to zero those blocks
5876                  */
5877                 for (j=sh->disks; j--;) {
5878                         sector_t s;
5879                         if (j == sh->pd_idx)
5880                                 continue;
5881                         if (conf->level == 6 &&
5882                             j == sh->qd_idx)
5883                                 continue;
5884                         s = raid5_compute_blocknr(sh, j, 0);
5885                         if (s < raid5_size(mddev, 0, 0)) {
5886                                 skipped_disk = 1;
5887                                 continue;
5888                         }
5889                         memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE);
5890                         set_bit(R5_Expanded, &sh->dev[j].flags);
5891                         set_bit(R5_UPTODATE, &sh->dev[j].flags);
5892                 }
5893                 if (!skipped_disk) {
5894                         set_bit(STRIPE_EXPAND_READY, &sh->state);
5895                         set_bit(STRIPE_HANDLE, &sh->state);
5896                 }
5897                 list_add(&sh->lru, &stripes);
5898         }
5899         spin_lock_irq(&conf->device_lock);
5900         if (mddev->reshape_backwards)
5901                 conf->reshape_progress -= reshape_sectors * new_data_disks;
5902         else
5903                 conf->reshape_progress += reshape_sectors * new_data_disks;
5904         spin_unlock_irq(&conf->device_lock);
5905         /* Ok, those stripe are ready. We can start scheduling
5906          * reads on the source stripes.
5907          * The source stripes are determined by mapping the first and last
5908          * block on the destination stripes.
5909          */
5910         first_sector =
5911                 raid5_compute_sector(conf, stripe_addr*(new_data_disks),
5912                                      1, &dd_idx, NULL);
5913         last_sector =
5914                 raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
5915                                             * new_data_disks - 1),
5916                                      1, &dd_idx, NULL);
5917         if (last_sector >= mddev->dev_sectors)
5918                 last_sector = mddev->dev_sectors - 1;
5919         while (first_sector <= last_sector) {
5920                 sh = raid5_get_active_stripe(conf, first_sector, 1, 0, 1);
5921                 set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
5922                 set_bit(STRIPE_HANDLE, &sh->state);
5923                 raid5_release_stripe(sh);
5924                 first_sector += STRIPE_SECTORS;
5925         }
5926         /* Now that the sources are clearly marked, we can release
5927          * the destination stripes
5928          */
5929         while (!list_empty(&stripes)) {
5930                 sh = list_entry(stripes.next, struct stripe_head, lru);
5931                 list_del_init(&sh->lru);
5932                 raid5_release_stripe(sh);
5933         }
5934         /* If this takes us to the resync_max point where we have to pause,
5935          * then we need to write out the superblock.
5936          */
5937         sector_nr += reshape_sectors;
5938         retn = reshape_sectors;
5939 finish:
5940         if (mddev->curr_resync_completed > mddev->resync_max ||
5941             (sector_nr - mddev->curr_resync_completed) * 2
5942             >= mddev->resync_max - mddev->curr_resync_completed) {
5943                 /* Cannot proceed until we've updated the superblock... */
5944                 wait_event(conf->wait_for_overlap,
5945                            atomic_read(&conf->reshape_stripes) == 0
5946                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5947                 if (atomic_read(&conf->reshape_stripes) != 0)
5948                         goto ret;
5949                 mddev->reshape_position = conf->reshape_progress;
5950                 mddev->curr_resync_completed = sector_nr;
5951                 conf->reshape_checkpoint = jiffies;
5952                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
5953                 md_wakeup_thread(mddev->thread);
5954                 wait_event(mddev->sb_wait,
5955                            !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)
5956                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5957                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5958                         goto ret;
5959                 spin_lock_irq(&conf->device_lock);
5960                 conf->reshape_safe = mddev->reshape_position;
5961                 spin_unlock_irq(&conf->device_lock);
5962                 wake_up(&conf->wait_for_overlap);
5963                 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5964         }
5965 ret:
5966         return retn;
5967 }
5968
5969 static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_nr,
5970                                           int *skipped)
5971 {
5972         struct r5conf *conf = mddev->private;
5973         struct stripe_head *sh;
5974         sector_t max_sector = mddev->dev_sectors;
5975         sector_t sync_blocks;
5976         int still_degraded = 0;
5977         int i;
5978
5979         if (sector_nr >= max_sector) {
5980                 /* just being told to finish up .. nothing much to do */
5981
5982                 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
5983                         end_reshape(conf);
5984                         return 0;
5985                 }
5986
5987                 if (mddev->curr_resync < max_sector) /* aborted */
5988                         bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
5989                                         &sync_blocks, 1);
5990                 else /* completed sync */
5991                         conf->fullsync = 0;
5992                 bitmap_close_sync(mddev->bitmap);
5993
5994                 return 0;
5995         }
5996
5997         /* Allow raid5_quiesce to complete */
5998         wait_event(conf->wait_for_overlap, conf->quiesce != 2);
5999
6000         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6001                 return reshape_request(mddev, sector_nr, skipped);
6002
6003         /* No need to check resync_max as we never do more than one
6004          * stripe, and as resync_max will always be on a chunk boundary,
6005          * if the check in md_do_sync didn't fire, there is no chance
6006          * of overstepping resync_max here
6007          */
6008
6009         /* if there is too many failed drives and we are trying
6010          * to resync, then assert that we are finished, because there is
6011          * nothing we can do.
6012          */
6013         if (mddev->degraded >= conf->max_degraded &&
6014             test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
6015                 sector_t rv = mddev->dev_sectors - sector_nr;
6016                 *skipped = 1;
6017                 return rv;
6018         }
6019         if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
6020             !conf->fullsync &&
6021             !bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
6022             sync_blocks >= STRIPE_SECTORS) {
6023                 /* we can skip this block, and probably more */
6024                 sync_blocks /= STRIPE_SECTORS;
6025                 *skipped = 1;
6026                 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
6027         }
6028
6029         bitmap_cond_end_sync(mddev->bitmap, sector_nr, false);
6030
6031         sh = raid5_get_active_stripe(conf, sector_nr, 0, 1, 0);
6032         if (sh == NULL) {
6033                 sh = raid5_get_active_stripe(conf, sector_nr, 0, 0, 0);
6034                 /* make sure we don't swamp the stripe cache if someone else
6035                  * is trying to get access
6036                  */
6037                 schedule_timeout_uninterruptible(1);
6038         }
6039         /* Need to check if array will still be degraded after recovery/resync
6040          * Note in case of > 1 drive failures it's possible we're rebuilding
6041          * one drive while leaving another faulty drive in array.
6042          */
6043         rcu_read_lock();
6044         for (i = 0; i < conf->raid_disks; i++) {
6045                 struct md_rdev *rdev = ACCESS_ONCE(conf->disks[i].rdev);
6046
6047                 if (rdev == NULL || test_bit(Faulty, &rdev->flags))
6048                         still_degraded = 1;
6049         }
6050         rcu_read_unlock();
6051
6052         bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
6053
6054         set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
6055         set_bit(STRIPE_HANDLE, &sh->state);
6056
6057         raid5_release_stripe(sh);
6058
6059         return STRIPE_SECTORS;
6060 }
6061
6062 static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio,
6063                                unsigned int offset)
6064 {
6065         /* We may not be able to submit a whole bio at once as there
6066          * may not be enough stripe_heads available.
6067          * We cannot pre-allocate enough stripe_heads as we may need
6068          * more than exist in the cache (if we allow ever large chunks).
6069          * So we do one stripe head at a time and record in
6070          * ->bi_hw_segments how many have been done.
6071          *
6072          * We *know* that this entire raid_bio is in one chunk, so
6073          * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
6074          */
6075         struct stripe_head *sh;
6076         int dd_idx;
6077         sector_t sector, logical_sector, last_sector;
6078         int scnt = 0;
6079         int handled = 0;
6080
6081         logical_sector = raid_bio->bi_iter.bi_sector &
6082                 ~((sector_t)STRIPE_SECTORS-1);
6083         sector = raid5_compute_sector(conf, logical_sector,
6084                                       0, &dd_idx, NULL);
6085         last_sector = bio_end_sector(raid_bio);
6086
6087         for (; logical_sector < last_sector;
6088              logical_sector += STRIPE_SECTORS,
6089                      sector += STRIPE_SECTORS,
6090                      scnt++) {
6091
6092                 if (scnt < offset)
6093                         /* already done this stripe */
6094                         continue;
6095
6096                 sh = raid5_get_active_stripe(conf, sector, 0, 1, 1);
6097
6098                 if (!sh) {
6099                         /* failed to get a stripe - must wait */
6100                         conf->retry_read_aligned = raid_bio;
6101                         conf->retry_read_offset = scnt;
6102                         return handled;
6103                 }
6104
6105                 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0, 0)) {
6106                         raid5_release_stripe(sh);
6107                         conf->retry_read_aligned = raid_bio;
6108                         conf->retry_read_offset = scnt;
6109                         return handled;
6110                 }
6111
6112                 set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
6113                 handle_stripe(sh);
6114                 raid5_release_stripe(sh);
6115                 handled++;
6116         }
6117
6118         bio_endio(raid_bio);
6119
6120         if (atomic_dec_and_test(&conf->active_aligned_reads))
6121                 wake_up(&conf->wait_for_quiescent);
6122         return handled;
6123 }
6124
6125 static int handle_active_stripes(struct r5conf *conf, int group,
6126                                  struct r5worker *worker,
6127                                  struct list_head *temp_inactive_list)
6128 {
6129         struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
6130         int i, batch_size = 0, hash;
6131         bool release_inactive = false;
6132
6133         while (batch_size < MAX_STRIPE_BATCH &&
6134                         (sh = __get_priority_stripe(conf, group)) != NULL)
6135                 batch[batch_size++] = sh;
6136
6137         if (batch_size == 0) {
6138                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6139                         if (!list_empty(temp_inactive_list + i))
6140                                 break;
6141                 if (i == NR_STRIPE_HASH_LOCKS) {
6142                         spin_unlock_irq(&conf->device_lock);
6143                         r5l_flush_stripe_to_raid(conf->log);
6144                         spin_lock_irq(&conf->device_lock);
6145                         return batch_size;
6146                 }
6147                 release_inactive = true;
6148         }
6149         spin_unlock_irq(&conf->device_lock);
6150
6151         release_inactive_stripe_list(conf, temp_inactive_list,
6152                                      NR_STRIPE_HASH_LOCKS);
6153
6154         r5l_flush_stripe_to_raid(conf->log);
6155         if (release_inactive) {
6156                 spin_lock_irq(&conf->device_lock);
6157                 return 0;
6158         }
6159
6160         for (i = 0; i < batch_size; i++)
6161                 handle_stripe(batch[i]);
6162         log_write_stripe_run(conf);
6163
6164         cond_resched();
6165
6166         spin_lock_irq(&conf->device_lock);
6167         for (i = 0; i < batch_size; i++) {
6168                 hash = batch[i]->hash_lock_index;
6169                 __release_stripe(conf, batch[i], &temp_inactive_list[hash]);
6170         }
6171         return batch_size;
6172 }
6173
6174 static void raid5_do_work(struct work_struct *work)
6175 {
6176         struct r5worker *worker = container_of(work, struct r5worker, work);
6177         struct r5worker_group *group = worker->group;
6178         struct r5conf *conf = group->conf;
6179         struct mddev *mddev = conf->mddev;
6180         int group_id = group - conf->worker_groups;
6181         int handled;
6182         struct blk_plug plug;
6183
6184         pr_debug("+++ raid5worker active\n");
6185
6186         blk_start_plug(&plug);
6187         handled = 0;
6188         spin_lock_irq(&conf->device_lock);
6189         while (1) {
6190                 int batch_size, released;
6191
6192                 released = release_stripe_list(conf, worker->temp_inactive_list);
6193
6194                 batch_size = handle_active_stripes(conf, group_id, worker,
6195                                                    worker->temp_inactive_list);
6196                 worker->working = false;
6197                 if (!batch_size && !released)
6198                         break;
6199                 handled += batch_size;
6200                 wait_event_lock_irq(mddev->sb_wait,
6201                         !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
6202                         conf->device_lock);
6203         }
6204         pr_debug("%d stripes handled\n", handled);
6205
6206         spin_unlock_irq(&conf->device_lock);
6207         blk_finish_plug(&plug);
6208
6209         pr_debug("--- raid5worker inactive\n");
6210 }
6211
6212 /*
6213  * This is our raid5 kernel thread.
6214  *
6215  * We scan the hash table for stripes which can be handled now.
6216  * During the scan, completed stripes are saved for us by the interrupt
6217  * handler, so that they will not have to wait for our next wakeup.
6218  */
6219 static void raid5d(struct md_thread *thread)
6220 {
6221         struct mddev *mddev = thread->mddev;
6222         struct r5conf *conf = mddev->private;
6223         int handled;
6224         struct blk_plug plug;
6225
6226         pr_debug("+++ raid5d active\n");
6227
6228         md_check_recovery(mddev);
6229
6230         blk_start_plug(&plug);
6231         handled = 0;
6232         spin_lock_irq(&conf->device_lock);
6233         while (1) {
6234                 struct bio *bio;
6235                 int batch_size, released;
6236                 unsigned int offset;
6237
6238                 released = release_stripe_list(conf, conf->temp_inactive_list);
6239                 if (released)
6240                         clear_bit(R5_DID_ALLOC, &conf->cache_state);
6241
6242                 if (
6243                     !list_empty(&conf->bitmap_list)) {
6244                         /* Now is a good time to flush some bitmap updates */
6245                         conf->seq_flush++;
6246                         spin_unlock_irq(&conf->device_lock);
6247                         bitmap_unplug(mddev->bitmap);
6248                         spin_lock_irq(&conf->device_lock);
6249                         conf->seq_write = conf->seq_flush;
6250                         activate_bit_delay(conf, conf->temp_inactive_list);
6251                 }
6252                 raid5_activate_delayed(conf);
6253
6254                 while ((bio = remove_bio_from_retry(conf, &offset))) {
6255                         int ok;
6256                         spin_unlock_irq(&conf->device_lock);
6257                         ok = retry_aligned_read(conf, bio, offset);
6258                         spin_lock_irq(&conf->device_lock);
6259                         if (!ok)
6260                                 break;
6261                         handled++;
6262                 }
6263
6264                 batch_size = handle_active_stripes(conf, ANY_GROUP, NULL,
6265                                                    conf->temp_inactive_list);
6266                 if (!batch_size && !released)
6267                         break;
6268                 handled += batch_size;
6269
6270                 if (mddev->sb_flags & ~(1 << MD_SB_CHANGE_PENDING)) {
6271                         spin_unlock_irq(&conf->device_lock);
6272                         md_check_recovery(mddev);
6273                         spin_lock_irq(&conf->device_lock);
6274                 }
6275         }
6276         pr_debug("%d stripes handled\n", handled);
6277
6278         spin_unlock_irq(&conf->device_lock);
6279         if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state) &&
6280             mutex_trylock(&conf->cache_size_mutex)) {
6281                 grow_one_stripe(conf, __GFP_NOWARN);
6282                 /* Set flag even if allocation failed.  This helps
6283                  * slow down allocation requests when mem is short
6284                  */
6285                 set_bit(R5_DID_ALLOC, &conf->cache_state);
6286                 mutex_unlock(&conf->cache_size_mutex);
6287         }
6288
6289         flush_deferred_bios(conf);
6290
6291         r5l_flush_stripe_to_raid(conf->log);
6292
6293         async_tx_issue_pending_all();
6294         blk_finish_plug(&plug);
6295
6296         pr_debug("--- raid5d inactive\n");
6297 }
6298
6299 static ssize_t
6300 raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
6301 {
6302         struct r5conf *conf;
6303         int ret = 0;
6304         spin_lock(&mddev->lock);
6305         conf = mddev->private;
6306         if (conf)
6307                 ret = sprintf(page, "%d\n", conf->min_nr_stripes);
6308         spin_unlock(&mddev->lock);
6309         return ret;
6310 }
6311
6312 int
6313 raid5_set_cache_size(struct mddev *mddev, int size)
6314 {
6315         struct r5conf *conf = mddev->private;
6316         int err;
6317
6318         if (size <= 16 || size > 32768)
6319                 return -EINVAL;
6320
6321         conf->min_nr_stripes = size;
6322         mutex_lock(&conf->cache_size_mutex);
6323         while (size < conf->max_nr_stripes &&
6324                drop_one_stripe(conf))
6325                 ;
6326         mutex_unlock(&conf->cache_size_mutex);
6327
6328
6329         err = md_allow_write(mddev);
6330         if (err)
6331                 return err;
6332
6333         mutex_lock(&conf->cache_size_mutex);
6334         while (size > conf->max_nr_stripes)
6335                 if (!grow_one_stripe(conf, GFP_KERNEL))
6336                         break;
6337         mutex_unlock(&conf->cache_size_mutex);
6338
6339         return 0;
6340 }
6341 EXPORT_SYMBOL(raid5_set_cache_size);
6342
6343 static ssize_t
6344 raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
6345 {
6346         struct r5conf *conf;
6347         unsigned long new;
6348         int err;
6349
6350         if (len >= PAGE_SIZE)
6351                 return -EINVAL;
6352         if (kstrtoul(page, 10, &new))
6353                 return -EINVAL;
6354         err = mddev_lock(mddev);
6355         if (err)
6356                 return err;
6357         conf = mddev->private;
6358         if (!conf)
6359                 err = -ENODEV;
6360         else
6361                 err = raid5_set_cache_size(mddev, new);
6362         mddev_unlock(mddev);
6363
6364         return err ?: len;
6365 }
6366
6367 static struct md_sysfs_entry
6368 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
6369                                 raid5_show_stripe_cache_size,
6370                                 raid5_store_stripe_cache_size);
6371
6372 static ssize_t
6373 raid5_show_rmw_level(struct mddev  *mddev, char *page)
6374 {
6375         struct r5conf *conf = mddev->private;
6376         if (conf)
6377                 return sprintf(page, "%d\n", conf->rmw_level);
6378         else
6379                 return 0;
6380 }
6381
6382 static ssize_t
6383 raid5_store_rmw_level(struct mddev  *mddev, const char *page, size_t len)
6384 {
6385         struct r5conf *conf = mddev->private;
6386         unsigned long new;
6387
6388         if (!conf)
6389                 return -ENODEV;
6390
6391         if (len >= PAGE_SIZE)
6392                 return -EINVAL;
6393
6394         if (kstrtoul(page, 10, &new))
6395                 return -EINVAL;
6396
6397         if (new != PARITY_DISABLE_RMW && !raid6_call.xor_syndrome)
6398                 return -EINVAL;
6399
6400         if (new != PARITY_DISABLE_RMW &&
6401             new != PARITY_ENABLE_RMW &&
6402             new != PARITY_PREFER_RMW)
6403                 return -EINVAL;
6404
6405         conf->rmw_level = new;
6406         return len;
6407 }
6408
6409 static struct md_sysfs_entry
6410 raid5_rmw_level = __ATTR(rmw_level, S_IRUGO | S_IWUSR,
6411                          raid5_show_rmw_level,
6412                          raid5_store_rmw_level);
6413
6414
6415 static ssize_t
6416 raid5_show_preread_threshold(struct mddev *mddev, char *page)
6417 {
6418         struct r5conf *conf;
6419         int ret = 0;
6420         spin_lock(&mddev->lock);
6421         conf = mddev->private;
6422         if (conf)
6423                 ret = sprintf(page, "%d\n", conf->bypass_threshold);
6424         spin_unlock(&mddev->lock);
6425         return ret;
6426 }
6427
6428 static ssize_t
6429 raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
6430 {
6431         struct r5conf *conf;
6432         unsigned long new;
6433         int err;
6434
6435         if (len >= PAGE_SIZE)
6436                 return -EINVAL;
6437         if (kstrtoul(page, 10, &new))
6438                 return -EINVAL;
6439
6440         err = mddev_lock(mddev);
6441         if (err)
6442                 return err;
6443         conf = mddev->private;
6444         if (!conf)
6445                 err = -ENODEV;
6446         else if (new > conf->min_nr_stripes)
6447                 err = -EINVAL;
6448         else
6449                 conf->bypass_threshold = new;
6450         mddev_unlock(mddev);
6451         return err ?: len;
6452 }
6453
6454 static struct md_sysfs_entry
6455 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
6456                                         S_IRUGO | S_IWUSR,
6457                                         raid5_show_preread_threshold,
6458                                         raid5_store_preread_threshold);
6459
6460 static ssize_t
6461 raid5_show_skip_copy(struct mddev *mddev, char *page)
6462 {
6463         struct r5conf *conf;
6464         int ret = 0;
6465         spin_lock(&mddev->lock);
6466         conf = mddev->private;
6467         if (conf)
6468                 ret = sprintf(page, "%d\n", conf->skip_copy);
6469         spin_unlock(&mddev->lock);
6470         return ret;
6471 }
6472
6473 static ssize_t
6474 raid5_store_skip_copy(struct mddev *mddev, const char *page, size_t len)
6475 {
6476         struct r5conf *conf;
6477         unsigned long new;
6478         int err;
6479
6480         if (len >= PAGE_SIZE)
6481                 return -EINVAL;
6482         if (kstrtoul(page, 10, &new))
6483                 return -EINVAL;
6484         new = !!new;
6485
6486         err = mddev_lock(mddev);
6487         if (err)
6488                 return err;
6489         conf = mddev->private;
6490         if (!conf)
6491                 err = -ENODEV;
6492         else if (new != conf->skip_copy) {
6493                 mddev_suspend(mddev);
6494                 conf->skip_copy = new;
6495                 if (new)
6496                         mddev->queue->backing_dev_info->capabilities |=
6497                                 BDI_CAP_STABLE_WRITES;
6498                 else
6499                         mddev->queue->backing_dev_info->capabilities &=
6500                                 ~BDI_CAP_STABLE_WRITES;
6501                 mddev_resume(mddev);
6502         }
6503         mddev_unlock(mddev);
6504         return err ?: len;
6505 }
6506
6507 static struct md_sysfs_entry
6508 raid5_skip_copy = __ATTR(skip_copy, S_IRUGO | S_IWUSR,
6509                                         raid5_show_skip_copy,
6510                                         raid5_store_skip_copy);
6511
6512 static ssize_t
6513 stripe_cache_active_show(struct mddev *mddev, char *page)
6514 {
6515         struct r5conf *conf = mddev->private;
6516         if (conf)
6517                 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
6518         else
6519                 return 0;
6520 }
6521
6522 static struct md_sysfs_entry
6523 raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
6524
6525 static ssize_t
6526 raid5_show_group_thread_cnt(struct mddev *mddev, char *page)
6527 {
6528         struct r5conf *conf;
6529         int ret = 0;
6530         spin_lock(&mddev->lock);
6531         conf = mddev->private;
6532         if (conf)
6533                 ret = sprintf(page, "%d\n", conf->worker_cnt_per_group);
6534         spin_unlock(&mddev->lock);
6535         return ret;
6536 }
6537
6538 static int alloc_thread_groups(struct r5conf *conf, int cnt,
6539                                int *group_cnt,
6540                                int *worker_cnt_per_group,
6541                                struct r5worker_group **worker_groups);
6542 static ssize_t
6543 raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
6544 {
6545         struct r5conf *conf;
6546         unsigned long new;
6547         int err;
6548         struct r5worker_group *new_groups, *old_groups;
6549         int group_cnt, worker_cnt_per_group;
6550
6551         if (len >= PAGE_SIZE)
6552                 return -EINVAL;
6553         if (kstrtoul(page, 10, &new))
6554                 return -EINVAL;
6555
6556         err = mddev_lock(mddev);
6557         if (err)
6558                 return err;
6559         conf = mddev->private;
6560         if (!conf)
6561                 err = -ENODEV;
6562         else if (new != conf->worker_cnt_per_group) {
6563                 mddev_suspend(mddev);
6564
6565                 old_groups = conf->worker_groups;
6566                 if (old_groups)
6567                         flush_workqueue(raid5_wq);
6568
6569                 err = alloc_thread_groups(conf, new,
6570                                           &group_cnt, &worker_cnt_per_group,
6571                                           &new_groups);
6572                 if (!err) {
6573                         spin_lock_irq(&conf->device_lock);
6574                         conf->group_cnt = group_cnt;
6575                         conf->worker_cnt_per_group = worker_cnt_per_group;
6576                         conf->worker_groups = new_groups;
6577                         spin_unlock_irq(&conf->device_lock);
6578
6579                         if (old_groups)
6580                                 kfree(old_groups[0].workers);
6581                         kfree(old_groups);
6582                 }
6583                 mddev_resume(mddev);
6584         }
6585         mddev_unlock(mddev);
6586
6587         return err ?: len;
6588 }
6589
6590 static struct md_sysfs_entry
6591 raid5_group_thread_cnt = __ATTR(group_thread_cnt, S_IRUGO | S_IWUSR,
6592                                 raid5_show_group_thread_cnt,
6593                                 raid5_store_group_thread_cnt);
6594
6595 static struct attribute *raid5_attrs[] =  {
6596         &raid5_stripecache_size.attr,
6597         &raid5_stripecache_active.attr,
6598         &raid5_preread_bypass_threshold.attr,
6599         &raid5_group_thread_cnt.attr,
6600         &raid5_skip_copy.attr,
6601         &raid5_rmw_level.attr,
6602         &r5c_journal_mode.attr,
6603         NULL,
6604 };
6605 static struct attribute_group raid5_attrs_group = {
6606         .name = NULL,
6607         .attrs = raid5_attrs,
6608 };
6609
6610 static int alloc_thread_groups(struct r5conf *conf, int cnt,
6611                                int *group_cnt,
6612                                int *worker_cnt_per_group,
6613                                struct r5worker_group **worker_groups)
6614 {
6615         int i, j, k;
6616         ssize_t size;
6617         struct r5worker *workers;
6618
6619         *worker_cnt_per_group = cnt;
6620         if (cnt == 0) {
6621                 *group_cnt = 0;
6622                 *worker_groups = NULL;
6623                 return 0;
6624         }
6625         *group_cnt = num_possible_nodes();
6626         size = sizeof(struct r5worker) * cnt;
6627         workers = kzalloc(size * *group_cnt, GFP_NOIO);
6628         *worker_groups = kzalloc(sizeof(struct r5worker_group) *
6629                                 *group_cnt, GFP_NOIO);
6630         if (!*worker_groups || !workers) {
6631                 kfree(workers);
6632                 kfree(*worker_groups);
6633                 return -ENOMEM;
6634         }
6635
6636         for (i = 0; i < *group_cnt; i++) {
6637                 struct r5worker_group *group;
6638
6639                 group = &(*worker_groups)[i];
6640                 INIT_LIST_HEAD(&group->handle_list);
6641                 INIT_LIST_HEAD(&group->loprio_list);
6642                 group->conf = conf;
6643                 group->workers = workers + i * cnt;
6644
6645                 for (j = 0; j < cnt; j++) {
6646                         struct r5worker *worker = group->workers + j;
6647                         worker->group = group;
6648                         INIT_WORK(&worker->work, raid5_do_work);
6649
6650                         for (k = 0; k < NR_STRIPE_HASH_LOCKS; k++)
6651                                 INIT_LIST_HEAD(worker->temp_inactive_list + k);
6652                 }
6653         }
6654
6655         return 0;
6656 }
6657
6658 static void free_thread_groups(struct r5conf *conf)
6659 {
6660         if (conf->worker_groups)
6661                 kfree(conf->worker_groups[0].workers);
6662         kfree(conf->worker_groups);
6663         conf->worker_groups = NULL;
6664 }
6665
6666 static sector_t
6667 raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
6668 {
6669         struct r5conf *conf = mddev->private;
6670
6671         if (!sectors)
6672                 sectors = mddev->dev_sectors;
6673         if (!raid_disks)
6674                 /* size is defined by the smallest of previous and new size */
6675                 raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
6676
6677         sectors &= ~((sector_t)conf->chunk_sectors - 1);
6678         sectors &= ~((sector_t)conf->prev_chunk_sectors - 1);
6679         return sectors * (raid_disks - conf->max_degraded);
6680 }
6681
6682 static void free_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6683 {
6684         safe_put_page(percpu->spare_page);
6685         if (percpu->scribble)
6686                 flex_array_free(percpu->scribble);
6687         percpu->spare_page = NULL;
6688         percpu->scribble = NULL;
6689 }
6690
6691 static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6692 {
6693         if (conf->level == 6 && !percpu->spare_page)
6694                 percpu->spare_page = alloc_page(GFP_KERNEL);
6695         if (!percpu->scribble)
6696                 percpu->scribble = scribble_alloc(max(conf->raid_disks,
6697                                                       conf->previous_raid_disks),
6698                                                   max(conf->chunk_sectors,
6699                                                       conf->prev_chunk_sectors)
6700                                                    / STRIPE_SECTORS,
6701                                                   GFP_KERNEL);
6702
6703         if (!percpu->scribble || (conf->level == 6 && !percpu->spare_page)) {
6704                 free_scratch_buffer(conf, percpu);
6705                 return -ENOMEM;
6706         }
6707
6708         return 0;
6709 }
6710
6711 static int raid456_cpu_dead(unsigned int cpu, struct hlist_node *node)
6712 {
6713         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
6714
6715         free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));
6716         return 0;
6717 }
6718
6719 static void raid5_free_percpu(struct r5conf *conf)
6720 {
6721         if (!conf->percpu)
6722                 return;
6723
6724         cpuhp_state_remove_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
6725         free_percpu(conf->percpu);
6726 }
6727
6728 static void free_conf(struct r5conf *conf)
6729 {
6730         int i;
6731
6732         log_exit(conf);
6733
6734         if (conf->shrinker.nr_deferred)
6735                 unregister_shrinker(&conf->shrinker);
6736
6737         free_thread_groups(conf);
6738         shrink_stripes(conf);
6739         raid5_free_percpu(conf);
6740         for (i = 0; i < conf->pool_size; i++)
6741                 if (conf->disks[i].extra_page)
6742                         put_page(conf->disks[i].extra_page);
6743         kfree(conf->disks);
6744         if (conf->bio_split)
6745                 bioset_free(conf->bio_split);
6746         kfree(conf->stripe_hashtbl);
6747         kfree(conf->pending_data);
6748         kfree(conf);
6749 }
6750
6751 static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
6752 {
6753         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
6754         struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);
6755
6756         if (alloc_scratch_buffer(conf, percpu)) {
6757                 pr_warn("%s: failed memory allocation for cpu%u\n",
6758                         __func__, cpu);
6759                 return -ENOMEM;
6760         }
6761         return 0;
6762 }
6763
6764 static int raid5_alloc_percpu(struct r5conf *conf)
6765 {
6766         int err = 0;
6767
6768         conf->percpu = alloc_percpu(struct raid5_percpu);
6769         if (!conf->percpu)
6770                 return -ENOMEM;
6771
6772         err = cpuhp_state_add_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
6773         if (!err) {
6774                 conf->scribble_disks = max(conf->raid_disks,
6775                         conf->previous_raid_disks);
6776                 conf->scribble_sectors = max(conf->chunk_sectors,
6777                         conf->prev_chunk_sectors);
6778         }
6779         return err;
6780 }
6781
6782 static unsigned long raid5_cache_scan(struct shrinker *shrink,
6783                                       struct shrink_control *sc)
6784 {
6785         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6786         unsigned long ret = SHRINK_STOP;
6787
6788         if (mutex_trylock(&conf->cache_size_mutex)) {
6789                 ret= 0;
6790                 while (ret < sc->nr_to_scan &&
6791                        conf->max_nr_stripes > conf->min_nr_stripes) {
6792                         if (drop_one_stripe(conf) == 0) {
6793                                 ret = SHRINK_STOP;
6794                                 break;
6795                         }
6796                         ret++;
6797                 }
6798                 mutex_unlock(&conf->cache_size_mutex);
6799         }
6800         return ret;
6801 }
6802
6803 static unsigned long raid5_cache_count(struct shrinker *shrink,
6804                                        struct shrink_control *sc)
6805 {
6806         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6807
6808         if (conf->max_nr_stripes < conf->min_nr_stripes)
6809                 /* unlikely, but not impossible */
6810                 return 0;
6811         return conf->max_nr_stripes - conf->min_nr_stripes;
6812 }
6813
6814 static struct r5conf *setup_conf(struct mddev *mddev)
6815 {
6816         struct r5conf *conf;
6817         int raid_disk, memory, max_disks;
6818         struct md_rdev *rdev;
6819         struct disk_info *disk;
6820         char pers_name[6];
6821         int i;
6822         int group_cnt, worker_cnt_per_group;
6823         struct r5worker_group *new_group;
6824
6825         if (mddev->new_level != 5
6826             && mddev->new_level != 4
6827             && mddev->new_level != 6) {
6828                 pr_warn("md/raid:%s: raid level not set to 4/5/6 (%d)\n",
6829                         mdname(mddev), mddev->new_level);
6830                 return ERR_PTR(-EIO);
6831         }
6832         if ((mddev->new_level == 5
6833              && !algorithm_valid_raid5(mddev->new_layout)) ||
6834             (mddev->new_level == 6
6835              && !algorithm_valid_raid6(mddev->new_layout))) {
6836                 pr_warn("md/raid:%s: layout %d not supported\n",
6837                         mdname(mddev), mddev->new_layout);
6838                 return ERR_PTR(-EIO);
6839         }
6840         if (mddev->new_level == 6 && mddev->raid_disks < 4) {
6841                 pr_warn("md/raid:%s: not enough configured devices (%d, minimum 4)\n",
6842                         mdname(mddev), mddev->raid_disks);
6843                 return ERR_PTR(-EINVAL);
6844         }
6845
6846         if (!mddev->new_chunk_sectors ||
6847             (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
6848             !is_power_of_2(mddev->new_chunk_sectors)) {
6849                 pr_warn("md/raid:%s: invalid chunk size %d\n",
6850                         mdname(mddev), mddev->new_chunk_sectors << 9);
6851                 return ERR_PTR(-EINVAL);
6852         }
6853
6854         conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
6855         if (conf == NULL)
6856                 goto abort;
6857         INIT_LIST_HEAD(&conf->free_list);
6858         INIT_LIST_HEAD(&conf->pending_list);
6859         conf->pending_data = kzalloc(sizeof(struct r5pending_data) *
6860                 PENDING_IO_MAX, GFP_KERNEL);
6861         if (!conf->pending_data)
6862                 goto abort;
6863         for (i = 0; i < PENDING_IO_MAX; i++)
6864                 list_add(&conf->pending_data[i].sibling, &conf->free_list);
6865         /* Don't enable multi-threading by default*/
6866         if (!alloc_thread_groups(conf, 0, &group_cnt, &worker_cnt_per_group,
6867                                  &new_group)) {
6868                 conf->group_cnt = group_cnt;
6869                 conf->worker_cnt_per_group = worker_cnt_per_group;
6870                 conf->worker_groups = new_group;
6871         } else
6872                 goto abort;
6873         spin_lock_init(&conf->device_lock);
6874         seqcount_init(&conf->gen_lock);
6875         mutex_init(&conf->cache_size_mutex);
6876         init_waitqueue_head(&conf->wait_for_quiescent);
6877         init_waitqueue_head(&conf->wait_for_stripe);
6878         init_waitqueue_head(&conf->wait_for_overlap);
6879         INIT_LIST_HEAD(&conf->handle_list);
6880         INIT_LIST_HEAD(&conf->loprio_list);
6881         INIT_LIST_HEAD(&conf->hold_list);
6882         INIT_LIST_HEAD(&conf->delayed_list);
6883         INIT_LIST_HEAD(&conf->bitmap_list);
6884         init_llist_head(&conf->released_stripes);
6885         atomic_set(&conf->active_stripes, 0);
6886         atomic_set(&conf->preread_active_stripes, 0);
6887         atomic_set(&conf->active_aligned_reads, 0);
6888         spin_lock_init(&conf->pending_bios_lock);
6889         conf->batch_bio_dispatch = true;
6890         rdev_for_each(rdev, mddev) {
6891                 if (test_bit(Journal, &rdev->flags))
6892                         continue;
6893                 if (blk_queue_nonrot(bdev_get_queue(rdev->bdev))) {
6894                         conf->batch_bio_dispatch = false;
6895                         break;
6896                 }
6897         }
6898
6899         conf->bypass_threshold = BYPASS_THRESHOLD;
6900         conf->recovery_disabled = mddev->recovery_disabled - 1;
6901
6902         conf->raid_disks = mddev->raid_disks;
6903         if (mddev->reshape_position == MaxSector)
6904                 conf->previous_raid_disks = mddev->raid_disks;
6905         else
6906                 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
6907         max_disks = max(conf->raid_disks, conf->previous_raid_disks);
6908
6909         conf->disks = kzalloc(max_disks * sizeof(struct disk_info),
6910                               GFP_KERNEL);
6911
6912         if (!conf->disks)
6913                 goto abort;
6914
6915         for (i = 0; i < max_disks; i++) {
6916                 conf->disks[i].extra_page = alloc_page(GFP_KERNEL);
6917                 if (!conf->disks[i].extra_page)
6918                         goto abort;
6919         }
6920
6921         conf->bio_split = bioset_create(BIO_POOL_SIZE, 0);
6922         if (!conf->bio_split)
6923                 goto abort;
6924         conf->mddev = mddev;
6925
6926         if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
6927                 goto abort;
6928
6929         /* We init hash_locks[0] separately to that it can be used
6930          * as the reference lock in the spin_lock_nest_lock() call
6931          * in lock_all_device_hash_locks_irq in order to convince
6932          * lockdep that we know what we are doing.
6933          */
6934         spin_lock_init(conf->hash_locks);
6935         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
6936                 spin_lock_init(conf->hash_locks + i);
6937
6938         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6939                 INIT_LIST_HEAD(conf->inactive_list + i);
6940
6941         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6942                 INIT_LIST_HEAD(conf->temp_inactive_list + i);
6943
6944         atomic_set(&conf->r5c_cached_full_stripes, 0);
6945         INIT_LIST_HEAD(&conf->r5c_full_stripe_list);
6946         atomic_set(&conf->r5c_cached_partial_stripes, 0);
6947         INIT_LIST_HEAD(&conf->r5c_partial_stripe_list);
6948         atomic_set(&conf->r5c_flushing_full_stripes, 0);
6949         atomic_set(&conf->r5c_flushing_partial_stripes, 0);
6950
6951         conf->level = mddev->new_level;
6952         conf->chunk_sectors = mddev->new_chunk_sectors;
6953         if (raid5_alloc_percpu(conf) != 0)
6954                 goto abort;
6955
6956         pr_debug("raid456: run(%s) called.\n", mdname(mddev));
6957
6958         rdev_for_each(rdev, mddev) {
6959                 raid_disk = rdev->raid_disk;
6960                 if (raid_disk >= max_disks
6961                     || raid_disk < 0 || test_bit(Journal, &rdev->flags))
6962                         continue;
6963                 disk = conf->disks + raid_disk;
6964
6965                 if (test_bit(Replacement, &rdev->flags)) {
6966                         if (disk->replacement)
6967                                 goto abort;
6968                         disk->replacement = rdev;
6969                 } else {
6970                         if (disk->rdev)
6971                                 goto abort;
6972                         disk->rdev = rdev;
6973                 }
6974
6975                 if (test_bit(In_sync, &rdev->flags)) {
6976                         char b[BDEVNAME_SIZE];
6977                         pr_info("md/raid:%s: device %s operational as raid disk %d\n",
6978                                 mdname(mddev), bdevname(rdev->bdev, b), raid_disk);
6979                 } else if (rdev->saved_raid_disk != raid_disk)
6980                         /* Cannot rely on bitmap to complete recovery */
6981                         conf->fullsync = 1;
6982         }
6983
6984         conf->level = mddev->new_level;
6985         if (conf->level == 6) {
6986                 conf->max_degraded = 2;
6987                 if (raid6_call.xor_syndrome)
6988                         conf->rmw_level = PARITY_ENABLE_RMW;
6989                 else
6990                         conf->rmw_level = PARITY_DISABLE_RMW;
6991         } else {
6992                 conf->max_degraded = 1;
6993                 conf->rmw_level = PARITY_ENABLE_RMW;
6994         }
6995         conf->algorithm = mddev->new_layout;
6996         conf->reshape_progress = mddev->reshape_position;
6997         if (conf->reshape_progress != MaxSector) {
6998                 conf->prev_chunk_sectors = mddev->chunk_sectors;
6999                 conf->prev_algo = mddev->layout;
7000         } else {
7001                 conf->prev_chunk_sectors = conf->chunk_sectors;
7002                 conf->prev_algo = conf->algorithm;
7003         }
7004
7005         conf->min_nr_stripes = NR_STRIPES;
7006         if (mddev->reshape_position != MaxSector) {
7007                 int stripes = max_t(int,
7008                         ((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4,
7009                         ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4);
7010                 conf->min_nr_stripes = max(NR_STRIPES, stripes);
7011                 if (conf->min_nr_stripes != NR_STRIPES)
7012                         pr_info("md/raid:%s: force stripe size %d for reshape\n",
7013                                 mdname(mddev), conf->min_nr_stripes);
7014         }
7015         memory = conf->min_nr_stripes * (sizeof(struct stripe_head) +
7016                  max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
7017         atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS);
7018         if (grow_stripes(conf, conf->min_nr_stripes)) {
7019                 pr_warn("md/raid:%s: couldn't allocate %dkB for buffers\n",
7020                         mdname(mddev), memory);
7021                 goto abort;
7022         } else
7023                 pr_debug("md/raid:%s: allocated %dkB\n", mdname(mddev), memory);
7024         /*
7025          * Losing a stripe head costs more than the time to refill it,
7026          * it reduces the queue depth and so can hurt throughput.
7027          * So set it rather large, scaled by number of devices.
7028          */
7029         conf->shrinker.seeks = DEFAULT_SEEKS * conf->raid_disks * 4;
7030         conf->shrinker.scan_objects = raid5_cache_scan;
7031         conf->shrinker.count_objects = raid5_cache_count;
7032         conf->shrinker.batch = 128;
7033         conf->shrinker.flags = 0;
7034         if (register_shrinker(&conf->shrinker)) {
7035                 pr_warn("md/raid:%s: couldn't register shrinker.\n",
7036                         mdname(mddev));
7037                 goto abort;
7038         }
7039
7040         sprintf(pers_name, "raid%d", mddev->new_level);
7041         conf->thread = md_register_thread(raid5d, mddev, pers_name);
7042         if (!conf->thread) {
7043                 pr_warn("md/raid:%s: couldn't allocate thread.\n",
7044                         mdname(mddev));
7045                 goto abort;
7046         }
7047
7048         return conf;
7049
7050  abort:
7051         if (conf) {
7052                 free_conf(conf);
7053                 return ERR_PTR(-EIO);
7054         } else
7055                 return ERR_PTR(-ENOMEM);
7056 }
7057
7058 static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
7059 {
7060         switch (algo) {
7061         case ALGORITHM_PARITY_0:
7062                 if (raid_disk < max_degraded)
7063                         return 1;
7064                 break;
7065         case ALGORITHM_PARITY_N:
7066                 if (raid_disk >= raid_disks - max_degraded)
7067                         return 1;
7068                 break;
7069         case ALGORITHM_PARITY_0_6:
7070                 if (raid_disk == 0 ||
7071                     raid_disk == raid_disks - 1)
7072                         return 1;
7073                 break;
7074         case ALGORITHM_LEFT_ASYMMETRIC_6:
7075         case ALGORITHM_RIGHT_ASYMMETRIC_6:
7076         case ALGORITHM_LEFT_SYMMETRIC_6:
7077         case ALGORITHM_RIGHT_SYMMETRIC_6:
7078                 if (raid_disk == raid_disks - 1)
7079                         return 1;
7080         }
7081         return 0;
7082 }
7083
7084 static int raid5_run(struct mddev *mddev)
7085 {
7086         struct r5conf *conf;
7087         int working_disks = 0;
7088         int dirty_parity_disks = 0;
7089         struct md_rdev *rdev;
7090         struct md_rdev *journal_dev = NULL;
7091         sector_t reshape_offset = 0;
7092         int i;
7093         long long min_offset_diff = 0;
7094         int first = 1;
7095
7096         if (mddev->recovery_cp != MaxSector)
7097                 pr_notice("md/raid:%s: not clean -- starting background reconstruction\n",
7098                           mdname(mddev));
7099
7100         rdev_for_each(rdev, mddev) {
7101                 long long diff;
7102
7103                 if (test_bit(Journal, &rdev->flags)) {
7104                         journal_dev = rdev;
7105                         continue;
7106                 }
7107                 if (rdev->raid_disk < 0)
7108                         continue;
7109                 diff = (rdev->new_data_offset - rdev->data_offset);
7110                 if (first) {
7111                         min_offset_diff = diff;
7112                         first = 0;
7113                 } else if (mddev->reshape_backwards &&
7114                          diff < min_offset_diff)
7115                         min_offset_diff = diff;
7116                 else if (!mddev->reshape_backwards &&
7117                          diff > min_offset_diff)
7118                         min_offset_diff = diff;
7119         }
7120
7121         if (mddev->reshape_position != MaxSector) {
7122                 /* Check that we can continue the reshape.
7123                  * Difficulties arise if the stripe we would write to
7124                  * next is at or after the stripe we would read from next.
7125                  * For a reshape that changes the number of devices, this
7126                  * is only possible for a very short time, and mdadm makes
7127                  * sure that time appears to have past before assembling
7128                  * the array.  So we fail if that time hasn't passed.
7129                  * For a reshape that keeps the number of devices the same
7130                  * mdadm must be monitoring the reshape can keeping the
7131                  * critical areas read-only and backed up.  It will start
7132                  * the array in read-only mode, so we check for that.
7133                  */
7134                 sector_t here_new, here_old;
7135                 int old_disks;
7136                 int max_degraded = (mddev->level == 6 ? 2 : 1);
7137                 int chunk_sectors;
7138                 int new_data_disks;
7139
7140                 if (journal_dev) {
7141                         pr_warn("md/raid:%s: don't support reshape with journal - aborting.\n",
7142                                 mdname(mddev));
7143                         return -EINVAL;
7144                 }
7145
7146                 if (mddev->new_level != mddev->level) {
7147                         pr_warn("md/raid:%s: unsupported reshape required - aborting.\n",
7148                                 mdname(mddev));
7149                         return -EINVAL;
7150                 }
7151                 old_disks = mddev->raid_disks - mddev->delta_disks;
7152                 /* reshape_position must be on a new-stripe boundary, and one
7153                  * further up in new geometry must map after here in old
7154                  * geometry.
7155                  * If the chunk sizes are different, then as we perform reshape
7156                  * in units of the largest of the two, reshape_position needs
7157                  * be a multiple of the largest chunk size times new data disks.
7158                  */
7159                 here_new = mddev->reshape_position;
7160                 chunk_sectors = max(mddev->chunk_sectors, mddev->new_chunk_sectors);
7161                 new_data_disks = mddev->raid_disks - max_degraded;
7162                 if (sector_div(here_new, chunk_sectors * new_data_disks)) {
7163                         pr_warn("md/raid:%s: reshape_position not on a stripe boundary\n",
7164                                 mdname(mddev));
7165                         return -EINVAL;
7166                 }
7167                 reshape_offset = here_new * chunk_sectors;
7168                 /* here_new is the stripe we will write to */
7169                 here_old = mddev->reshape_position;
7170                 sector_div(here_old, chunk_sectors * (old_disks-max_degraded));
7171                 /* here_old is the first stripe that we might need to read
7172                  * from */
7173                 if (mddev->delta_disks == 0) {
7174                         /* We cannot be sure it is safe to start an in-place
7175                          * reshape.  It is only safe if user-space is monitoring
7176                          * and taking constant backups.
7177                          * mdadm always starts a situation like this in
7178                          * readonly mode so it can take control before
7179                          * allowing any writes.  So just check for that.
7180                          */
7181                         if (abs(min_offset_diff) >= mddev->chunk_sectors &&
7182                             abs(min_offset_diff) >= mddev->new_chunk_sectors)
7183                                 /* not really in-place - so OK */;
7184                         else if (mddev->ro == 0) {
7185                                 pr_warn("md/raid:%s: in-place reshape must be started in read-only mode - aborting\n",
7186                                         mdname(mddev));
7187                                 return -EINVAL;
7188                         }
7189                 } else if (mddev->reshape_backwards
7190                     ? (here_new * chunk_sectors + min_offset_diff <=
7191                        here_old * chunk_sectors)
7192                     : (here_new * chunk_sectors >=
7193                        here_old * chunk_sectors + (-min_offset_diff))) {
7194                         /* Reading from the same stripe as writing to - bad */
7195                         pr_warn("md/raid:%s: reshape_position too early for auto-recovery - aborting.\n",
7196                                 mdname(mddev));
7197                         return -EINVAL;
7198                 }
7199                 pr_debug("md/raid:%s: reshape will continue\n", mdname(mddev));
7200                 /* OK, we should be able to continue; */
7201         } else {
7202                 BUG_ON(mddev->level != mddev->new_level);
7203                 BUG_ON(mddev->layout != mddev->new_layout);
7204                 BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
7205                 BUG_ON(mddev->delta_disks != 0);
7206         }
7207
7208         if (test_bit(MD_HAS_JOURNAL, &mddev->flags) &&
7209             test_bit(MD_HAS_PPL, &mddev->flags)) {
7210                 pr_warn("md/raid:%s: using journal device and PPL not allowed - disabling PPL\n",
7211                         mdname(mddev));
7212                 clear_bit(MD_HAS_PPL, &mddev->flags);
7213         }
7214
7215         if (mddev->private == NULL)
7216                 conf = setup_conf(mddev);
7217         else
7218                 conf = mddev->private;
7219
7220         if (IS_ERR(conf))
7221                 return PTR_ERR(conf);
7222
7223         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
7224                 if (!journal_dev) {
7225                         pr_warn("md/raid:%s: journal disk is missing, force array readonly\n",
7226                                 mdname(mddev));
7227                         mddev->ro = 1;
7228                         set_disk_ro(mddev->gendisk, 1);
7229                 } else if (mddev->recovery_cp == MaxSector)
7230                         set_bit(MD_JOURNAL_CLEAN, &mddev->flags);
7231         }
7232
7233         conf->min_offset_diff = min_offset_diff;
7234         mddev->thread = conf->thread;
7235         conf->thread = NULL;
7236         mddev->private = conf;
7237
7238         for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
7239              i++) {
7240                 rdev = conf->disks[i].rdev;
7241                 if (!rdev && conf->disks[i].replacement) {
7242                         /* The replacement is all we have yet */
7243                         rdev = conf->disks[i].replacement;
7244                         conf->disks[i].replacement = NULL;
7245                         clear_bit(Replacement, &rdev->flags);
7246                         conf->disks[i].rdev = rdev;
7247                 }
7248                 if (!rdev)
7249                         continue;
7250                 if (conf->disks[i].replacement &&
7251                     conf->reshape_progress != MaxSector) {
7252                         /* replacements and reshape simply do not mix. */
7253                         pr_warn("md: cannot handle concurrent replacement and reshape.\n");
7254                         goto abort;
7255                 }
7256                 if (test_bit(In_sync, &rdev->flags)) {
7257                         working_disks++;
7258                         continue;
7259                 }
7260                 /* This disc is not fully in-sync.  However if it
7261                  * just stored parity (beyond the recovery_offset),
7262                  * when we don't need to be concerned about the
7263                  * array being dirty.
7264                  * When reshape goes 'backwards', we never have
7265                  * partially completed devices, so we only need
7266                  * to worry about reshape going forwards.
7267                  */
7268                 /* Hack because v0.91 doesn't store recovery_offset properly. */
7269                 if (mddev->major_version == 0 &&
7270                     mddev->minor_version > 90)
7271                         rdev->recovery_offset = reshape_offset;
7272
7273                 if (rdev->recovery_offset < reshape_offset) {
7274                         /* We need to check old and new layout */
7275                         if (!only_parity(rdev->raid_disk,
7276                                          conf->algorithm,
7277                                          conf->raid_disks,
7278                                          conf->max_degraded))
7279                                 continue;
7280                 }
7281                 if (!only_parity(rdev->raid_disk,
7282                                  conf->prev_algo,
7283                                  conf->previous_raid_disks,
7284                                  conf->max_degraded))
7285                         continue;
7286                 dirty_parity_disks++;
7287         }
7288
7289         /*
7290          * 0 for a fully functional array, 1 or 2 for a degraded array.
7291          */
7292         mddev->degraded = raid5_calc_degraded(conf);
7293
7294         if (has_failed(conf)) {
7295                 pr_crit("md/raid:%s: not enough operational devices (%d/%d failed)\n",
7296                         mdname(mddev), mddev->degraded, conf->raid_disks);
7297                 goto abort;
7298         }
7299
7300         /* device size must be a multiple of chunk size */
7301         mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
7302         mddev->resync_max_sectors = mddev->dev_sectors;
7303
7304         if (mddev->degraded > dirty_parity_disks &&
7305             mddev->recovery_cp != MaxSector) {
7306                 if (test_bit(MD_HAS_PPL, &mddev->flags))
7307                         pr_crit("md/raid:%s: starting dirty degraded array with PPL.\n",
7308                                 mdname(mddev));
7309                 else if (mddev->ok_start_degraded)
7310                         pr_crit("md/raid:%s: starting dirty degraded array - data corruption possible.\n",
7311                                 mdname(mddev));
7312                 else {
7313                         pr_crit("md/raid:%s: cannot start dirty degraded array.\n",
7314                                 mdname(mddev));
7315                         goto abort;
7316                 }
7317         }
7318
7319         pr_info("md/raid:%s: raid level %d active with %d out of %d devices, algorithm %d\n",
7320                 mdname(mddev), conf->level,
7321                 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
7322                 mddev->new_layout);
7323
7324         print_raid5_conf(conf);
7325
7326         if (conf->reshape_progress != MaxSector) {
7327                 conf->reshape_safe = conf->reshape_progress;
7328                 atomic_set(&conf->reshape_stripes, 0);
7329                 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7330                 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7331                 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7332                 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7333                 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7334                                                         "reshape");
7335         }
7336
7337         /* Ok, everything is just fine now */
7338         if (mddev->to_remove == &raid5_attrs_group)
7339                 mddev->to_remove = NULL;
7340         else if (mddev->kobj.sd &&
7341             sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
7342                 pr_warn("raid5: failed to create sysfs attributes for %s\n",
7343                         mdname(mddev));
7344         md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
7345
7346         if (mddev->queue) {
7347                 int chunk_size;
7348                 /* read-ahead size must cover two whole stripes, which
7349                  * is 2 * (datadisks) * chunksize where 'n' is the
7350                  * number of raid devices
7351                  */
7352                 int data_disks = conf->previous_raid_disks - conf->max_degraded;
7353                 int stripe = data_disks *
7354                         ((mddev->chunk_sectors << 9) / PAGE_SIZE);
7355                 if (mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
7356                         mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
7357
7358                 chunk_size = mddev->chunk_sectors << 9;
7359                 blk_queue_io_min(mddev->queue, chunk_size);
7360                 blk_queue_io_opt(mddev->queue, chunk_size *
7361                                  (conf->raid_disks - conf->max_degraded));
7362                 mddev->queue->limits.raid_partial_stripes_expensive = 1;
7363                 /*
7364                  * We can only discard a whole stripe. It doesn't make sense to
7365                  * discard data disk but write parity disk
7366                  */
7367                 stripe = stripe * PAGE_SIZE;
7368                 /* Round up to power of 2, as discard handling
7369                  * currently assumes that */
7370                 while ((stripe-1) & stripe)
7371                         stripe = (stripe | (stripe-1)) + 1;
7372                 mddev->queue->limits.discard_alignment = stripe;
7373                 mddev->queue->limits.discard_granularity = stripe;
7374
7375                 blk_queue_max_write_same_sectors(mddev->queue, 0);
7376                 blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
7377
7378                 rdev_for_each(rdev, mddev) {
7379                         disk_stack_limits(mddev->gendisk, rdev->bdev,
7380                                           rdev->data_offset << 9);
7381                         disk_stack_limits(mddev->gendisk, rdev->bdev,
7382                                           rdev->new_data_offset << 9);
7383                 }
7384
7385                 /*
7386                  * zeroing is required, otherwise data
7387                  * could be lost. Consider a scenario: discard a stripe
7388                  * (the stripe could be inconsistent if
7389                  * discard_zeroes_data is 0); write one disk of the
7390                  * stripe (the stripe could be inconsistent again
7391                  * depending on which disks are used to calculate
7392                  * parity); the disk is broken; The stripe data of this
7393                  * disk is lost.
7394                  *
7395                  * We only allow DISCARD if the sysadmin has confirmed that
7396                  * only safe devices are in use by setting a module parameter.
7397                  * A better idea might be to turn DISCARD into WRITE_ZEROES
7398                  * requests, as that is required to be safe.
7399                  */
7400                 if (devices_handle_discard_safely &&
7401                     mddev->queue->limits.max_discard_sectors >= (stripe >> 9) &&
7402                     mddev->queue->limits.discard_granularity >= stripe)
7403                         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
7404                                                 mddev->queue);
7405                 else
7406                         queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
7407                                                 mddev->queue);
7408
7409                 blk_queue_max_hw_sectors(mddev->queue, UINT_MAX);
7410         }
7411
7412         if (log_init(conf, journal_dev, raid5_has_ppl(conf)))
7413                 goto abort;
7414
7415         return 0;
7416 abort:
7417         md_unregister_thread(&mddev->thread);
7418         print_raid5_conf(conf);
7419         free_conf(conf);
7420         mddev->private = NULL;
7421         pr_warn("md/raid:%s: failed to run raid set.\n", mdname(mddev));
7422         return -EIO;
7423 }
7424
7425 static void raid5_free(struct mddev *mddev, void *priv)
7426 {
7427         struct r5conf *conf = priv;
7428
7429         free_conf(conf);
7430         mddev->to_remove = &raid5_attrs_group;
7431 }
7432
7433 static void raid5_status(struct seq_file *seq, struct mddev *mddev)
7434 {
7435         struct r5conf *conf = mddev->private;
7436         int i;
7437
7438         seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
7439                 conf->chunk_sectors / 2, mddev->layout);
7440         seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
7441         rcu_read_lock();
7442         for (i = 0; i < conf->raid_disks; i++) {
7443                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
7444                 seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
7445         }
7446         rcu_read_unlock();
7447         seq_printf (seq, "]");
7448 }
7449
7450 static void print_raid5_conf (struct r5conf *conf)
7451 {
7452         int i;
7453         struct disk_info *tmp;
7454
7455         pr_debug("RAID conf printout:\n");
7456         if (!conf) {
7457                 pr_debug("(conf==NULL)\n");
7458                 return;
7459         }
7460         pr_debug(" --- level:%d rd:%d wd:%d\n", conf->level,
7461                conf->raid_disks,
7462                conf->raid_disks - conf->mddev->degraded);
7463
7464         for (i = 0; i < conf->raid_disks; i++) {
7465                 char b[BDEVNAME_SIZE];
7466                 tmp = conf->disks + i;
7467                 if (tmp->rdev)
7468                         pr_debug(" disk %d, o:%d, dev:%s\n",
7469                                i, !test_bit(Faulty, &tmp->rdev->flags),
7470                                bdevname(tmp->rdev->bdev, b));
7471         }
7472 }
7473
7474 static int raid5_spare_active(struct mddev *mddev)
7475 {
7476         int i;
7477         struct r5conf *conf = mddev->private;
7478         struct disk_info *tmp;
7479         int count = 0;
7480         unsigned long flags;
7481
7482         for (i = 0; i < conf->raid_disks; i++) {
7483                 tmp = conf->disks + i;
7484                 if (tmp->replacement
7485                     && tmp->replacement->recovery_offset == MaxSector
7486                     && !test_bit(Faulty, &tmp->replacement->flags)
7487                     && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
7488                         /* Replacement has just become active. */
7489                         if (!tmp->rdev
7490                             || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
7491                                 count++;
7492                         if (tmp->rdev) {
7493                                 /* Replaced device not technically faulty,
7494                                  * but we need to be sure it gets removed
7495                                  * and never re-added.
7496                                  */
7497                                 set_bit(Faulty, &tmp->rdev->flags);
7498                                 sysfs_notify_dirent_safe(
7499                                         tmp->rdev->sysfs_state);
7500                         }
7501                         sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
7502                 } else if (tmp->rdev
7503                     && tmp->rdev->recovery_offset == MaxSector
7504                     && !test_bit(Faulty, &tmp->rdev->flags)
7505                     && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
7506                         count++;
7507                         sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
7508                 }
7509         }
7510         spin_lock_irqsave(&conf->device_lock, flags);
7511         mddev->degraded = raid5_calc_degraded(conf);
7512         spin_unlock_irqrestore(&conf->device_lock, flags);
7513         print_raid5_conf(conf);
7514         return count;
7515 }
7516
7517 static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
7518 {
7519         struct r5conf *conf = mddev->private;
7520         int err = 0;
7521         int number = rdev->raid_disk;
7522         struct md_rdev **rdevp;
7523         struct disk_info *p = conf->disks + number;
7524
7525         print_raid5_conf(conf);
7526         if (test_bit(Journal, &rdev->flags) && conf->log) {
7527                 /*
7528                  * we can't wait pending write here, as this is called in
7529                  * raid5d, wait will deadlock.
7530                  * neilb: there is no locking about new writes here,
7531                  * so this cannot be safe.
7532                  */
7533                 if (atomic_read(&conf->active_stripes)) {
7534                         return -EBUSY;
7535                 }
7536                 log_exit(conf);
7537                 return 0;
7538         }
7539         if (rdev == p->rdev)
7540                 rdevp = &p->rdev;
7541         else if (rdev == p->replacement)
7542                 rdevp = &p->replacement;
7543         else
7544                 return 0;
7545
7546         if (number >= conf->raid_disks &&
7547             conf->reshape_progress == MaxSector)
7548                 clear_bit(In_sync, &rdev->flags);
7549
7550         if (test_bit(In_sync, &rdev->flags) ||
7551             atomic_read(&rdev->nr_pending)) {
7552                 err = -EBUSY;
7553                 goto abort;
7554         }
7555         /* Only remove non-faulty devices if recovery
7556          * isn't possible.
7557          */
7558         if (!test_bit(Faulty, &rdev->flags) &&
7559             mddev->recovery_disabled != conf->recovery_disabled &&
7560             !has_failed(conf) &&
7561             (!p->replacement || p->replacement == rdev) &&
7562             number < conf->raid_disks) {
7563                 err = -EBUSY;
7564                 goto abort;
7565         }
7566         *rdevp = NULL;
7567         if (!test_bit(RemoveSynchronized, &rdev->flags)) {
7568                 synchronize_rcu();
7569                 if (atomic_read(&rdev->nr_pending)) {
7570                         /* lost the race, try later */
7571                         err = -EBUSY;
7572                         *rdevp = rdev;
7573                 }
7574         }
7575         if (!err) {
7576                 err = log_modify(conf, rdev, false);
7577                 if (err)
7578                         goto abort;
7579         }
7580         if (p->replacement) {
7581                 /* We must have just cleared 'rdev' */
7582                 p->rdev = p->replacement;
7583                 clear_bit(Replacement, &p->replacement->flags);
7584                 smp_mb(); /* Make sure other CPUs may see both as identical
7585                            * but will never see neither - if they are careful
7586                            */
7587                 p->replacement = NULL;
7588
7589                 if (!err)
7590                         err = log_modify(conf, p->rdev, true);
7591         }
7592
7593         clear_bit(WantReplacement, &rdev->flags);
7594 abort:
7595
7596         print_raid5_conf(conf);
7597         return err;
7598 }
7599
7600 static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
7601 {
7602         struct r5conf *conf = mddev->private;
7603         int err = -EEXIST;
7604         int disk;
7605         struct disk_info *p;
7606         int first = 0;
7607         int last = conf->raid_disks - 1;
7608
7609         if (test_bit(Journal, &rdev->flags)) {
7610                 if (conf->log)
7611                         return -EBUSY;
7612
7613                 rdev->raid_disk = 0;
7614                 /*
7615                  * The array is in readonly mode if journal is missing, so no
7616                  * write requests running. We should be safe
7617                  */
7618                 log_init(conf, rdev, false);
7619                 return 0;
7620         }
7621         if (mddev->recovery_disabled == conf->recovery_disabled)
7622                 return -EBUSY;
7623
7624         if (rdev->saved_raid_disk < 0 && has_failed(conf))
7625                 /* no point adding a device */
7626                 return -EINVAL;
7627
7628         if (rdev->raid_disk >= 0)
7629                 first = last = rdev->raid_disk;
7630
7631         /*
7632          * find the disk ... but prefer rdev->saved_raid_disk
7633          * if possible.
7634          */
7635         if (rdev->saved_raid_disk >= 0 &&
7636             rdev->saved_raid_disk >= first &&
7637             conf->disks[rdev->saved_raid_disk].rdev == NULL)
7638                 first = rdev->saved_raid_disk;
7639
7640         for (disk = first; disk <= last; disk++) {
7641                 p = conf->disks + disk;
7642                 if (p->rdev == NULL) {
7643                         clear_bit(In_sync, &rdev->flags);
7644                         rdev->raid_disk = disk;
7645                         if (rdev->saved_raid_disk != disk)
7646                                 conf->fullsync = 1;
7647                         rcu_assign_pointer(p->rdev, rdev);
7648
7649                         err = log_modify(conf, rdev, true);
7650
7651                         goto out;
7652                 }
7653         }
7654         for (disk = first; disk <= last; disk++) {
7655                 p = conf->disks + disk;
7656                 if (test_bit(WantReplacement, &p->rdev->flags) &&
7657                     p->replacement == NULL) {
7658                         clear_bit(In_sync, &rdev->flags);
7659                         set_bit(Replacement, &rdev->flags);
7660                         rdev->raid_disk = disk;
7661                         err = 0;
7662                         conf->fullsync = 1;
7663                         rcu_assign_pointer(p->replacement, rdev);
7664                         break;
7665                 }
7666         }
7667 out:
7668         print_raid5_conf(conf);
7669         return err;
7670 }
7671
7672 static int raid5_resize(struct mddev *mddev, sector_t sectors)
7673 {
7674         /* no resync is happening, and there is enough space
7675          * on all devices, so we can resize.
7676          * We need to make sure resync covers any new space.
7677          * If the array is shrinking we should possibly wait until
7678          * any io in the removed space completes, but it hardly seems
7679          * worth it.
7680          */
7681         sector_t newsize;
7682         struct r5conf *conf = mddev->private;
7683
7684         if (conf->log || raid5_has_ppl(conf))
7685                 return -EINVAL;
7686         sectors &= ~((sector_t)conf->chunk_sectors - 1);
7687         newsize = raid5_size(mddev, sectors, mddev->raid_disks);
7688         if (mddev->external_size &&
7689             mddev->array_sectors > newsize)
7690                 return -EINVAL;
7691         if (mddev->bitmap) {
7692                 int ret = bitmap_resize(mddev->bitmap, sectors, 0, 0);
7693                 if (ret)
7694                         return ret;
7695         }
7696         md_set_array_sectors(mddev, newsize);
7697         if (sectors > mddev->dev_sectors &&
7698             mddev->recovery_cp > mddev->dev_sectors) {
7699                 mddev->recovery_cp = mddev->dev_sectors;
7700                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7701         }
7702         mddev->dev_sectors = sectors;
7703         mddev->resync_max_sectors = sectors;
7704         return 0;
7705 }
7706
7707 static int check_stripe_cache(struct mddev *mddev)
7708 {
7709         /* Can only proceed if there are plenty of stripe_heads.
7710          * We need a minimum of one full stripe,, and for sensible progress
7711          * it is best to have about 4 times that.
7712          * If we require 4 times, then the default 256 4K stripe_heads will
7713          * allow for chunk sizes up to 256K, which is probably OK.
7714          * If the chunk size is greater, user-space should request more
7715          * stripe_heads first.
7716          */
7717         struct r5conf *conf = mddev->private;
7718         if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4
7719             > conf->min_nr_stripes ||
7720             ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4
7721             > conf->min_nr_stripes) {
7722                 pr_warn("md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
7723                         mdname(mddev),
7724                         ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
7725                          / STRIPE_SIZE)*4);
7726                 return 0;
7727         }
7728         return 1;
7729 }
7730
7731 static int check_reshape(struct mddev *mddev)
7732 {
7733         struct r5conf *conf = mddev->private;
7734
7735         if (conf->log || raid5_has_ppl(conf))
7736                 return -EINVAL;
7737         if (mddev->delta_disks == 0 &&
7738             mddev->new_layout == mddev->layout &&
7739             mddev->new_chunk_sectors == mddev->chunk_sectors)
7740                 return 0; /* nothing to do */
7741         if (has_failed(conf))
7742                 return -EINVAL;
7743         if (mddev->delta_disks < 0 && mddev->reshape_position == MaxSector) {
7744                 /* We might be able to shrink, but the devices must
7745                  * be made bigger first.
7746                  * For raid6, 4 is the minimum size.
7747                  * Otherwise 2 is the minimum
7748                  */
7749                 int min = 2;
7750                 if (mddev->level == 6)
7751                         min = 4;
7752                 if (mddev->raid_disks + mddev->delta_disks < min)
7753                         return -EINVAL;
7754         }
7755
7756         if (!check_stripe_cache(mddev))
7757                 return -ENOSPC;
7758
7759         if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
7760             mddev->delta_disks > 0)
7761                 if (resize_chunks(conf,
7762                                   conf->previous_raid_disks
7763                                   + max(0, mddev->delta_disks),
7764                                   max(mddev->new_chunk_sectors,
7765                                       mddev->chunk_sectors)
7766                             ) < 0)
7767                         return -ENOMEM;
7768
7769         if (conf->previous_raid_disks + mddev->delta_disks <= conf->pool_size)
7770                 return 0; /* never bother to shrink */
7771         return resize_stripes(conf, (conf->previous_raid_disks
7772                                      + mddev->delta_disks));
7773 }
7774
7775 static int raid5_start_reshape(struct mddev *mddev)
7776 {
7777         struct r5conf *conf = mddev->private;
7778         struct md_rdev *rdev;
7779         int spares = 0;
7780         unsigned long flags;
7781
7782         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
7783                 return -EBUSY;
7784
7785         if (!check_stripe_cache(mddev))
7786                 return -ENOSPC;
7787
7788         if (has_failed(conf))
7789                 return -EINVAL;
7790
7791         rdev_for_each(rdev, mddev) {
7792                 if (!test_bit(In_sync, &rdev->flags)
7793                     && !test_bit(Faulty, &rdev->flags))
7794                         spares++;
7795         }
7796
7797         if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
7798                 /* Not enough devices even to make a degraded array
7799                  * of that size
7800                  */
7801                 return -EINVAL;
7802
7803         /* Refuse to reduce size of the array.  Any reductions in
7804          * array size must be through explicit setting of array_size
7805          * attribute.
7806          */
7807         if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
7808             < mddev->array_sectors) {
7809                 pr_warn("md/raid:%s: array size must be reduced before number of disks\n",
7810                         mdname(mddev));
7811                 return -EINVAL;
7812         }
7813
7814         atomic_set(&conf->reshape_stripes, 0);
7815         spin_lock_irq(&conf->device_lock);
7816         write_seqcount_begin(&conf->gen_lock);
7817         conf->previous_raid_disks = conf->raid_disks;
7818         conf->raid_disks += mddev->delta_disks;
7819         conf->prev_chunk_sectors = conf->chunk_sectors;
7820         conf->chunk_sectors = mddev->new_chunk_sectors;
7821         conf->prev_algo = conf->algorithm;
7822         conf->algorithm = mddev->new_layout;
7823         conf->generation++;
7824         /* Code that selects data_offset needs to see the generation update
7825          * if reshape_progress has been set - so a memory barrier needed.
7826          */
7827         smp_mb();
7828         if (mddev->reshape_backwards)
7829                 conf->reshape_progress = raid5_size(mddev, 0, 0);
7830         else
7831                 conf->reshape_progress = 0;
7832         conf->reshape_safe = conf->reshape_progress;
7833         write_seqcount_end(&conf->gen_lock);
7834         spin_unlock_irq(&conf->device_lock);
7835
7836         /* Now make sure any requests that proceeded on the assumption
7837          * the reshape wasn't running - like Discard or Read - have
7838          * completed.
7839          */
7840         mddev_suspend(mddev);
7841         mddev_resume(mddev);
7842
7843         /* Add some new drives, as many as will fit.
7844          * We know there are enough to make the newly sized array work.
7845          * Don't add devices if we are reducing the number of
7846          * devices in the array.  This is because it is not possible
7847          * to correctly record the "partially reconstructed" state of
7848          * such devices during the reshape and confusion could result.
7849          */
7850         if (mddev->delta_disks >= 0) {
7851                 rdev_for_each(rdev, mddev)
7852                         if (rdev->raid_disk < 0 &&
7853                             !test_bit(Faulty, &rdev->flags)) {
7854                                 if (raid5_add_disk(mddev, rdev) == 0) {
7855                                         if (rdev->raid_disk
7856                                             >= conf->previous_raid_disks)
7857                                                 set_bit(In_sync, &rdev->flags);
7858                                         else
7859                                                 rdev->recovery_offset = 0;
7860
7861                                         if (sysfs_link_rdev(mddev, rdev))
7862                                                 /* Failure here is OK */;
7863                                 }
7864                         } else if (rdev->raid_disk >= conf->previous_raid_disks
7865                                    && !test_bit(Faulty, &rdev->flags)) {
7866                                 /* This is a spare that was manually added */
7867                                 set_bit(In_sync, &rdev->flags);
7868                         }
7869
7870                 /* When a reshape changes the number of devices,
7871                  * ->degraded is measured against the larger of the
7872                  * pre and post number of devices.
7873                  */
7874                 spin_lock_irqsave(&conf->device_lock, flags);
7875                 mddev->degraded = raid5_calc_degraded(conf);
7876                 spin_unlock_irqrestore(&conf->device_lock, flags);
7877         }
7878         mddev->raid_disks = conf->raid_disks;
7879         mddev->reshape_position = conf->reshape_progress;
7880         set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
7881
7882         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7883         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7884         clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
7885         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7886         set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7887         mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7888                                                 "reshape");
7889         if (!mddev->sync_thread) {
7890                 mddev->recovery = 0;
7891                 spin_lock_irq(&conf->device_lock);
7892                 write_seqcount_begin(&conf->gen_lock);
7893                 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
7894                 mddev->new_chunk_sectors =
7895                         conf->chunk_sectors = conf->prev_chunk_sectors;
7896                 mddev->new_layout = conf->algorithm = conf->prev_algo;
7897                 rdev_for_each(rdev, mddev)
7898                         rdev->new_data_offset = rdev->data_offset;
7899                 smp_wmb();
7900                 conf->generation --;
7901                 conf->reshape_progress = MaxSector;
7902                 mddev->reshape_position = MaxSector;
7903                 write_seqcount_end(&conf->gen_lock);
7904                 spin_unlock_irq(&conf->device_lock);
7905                 return -EAGAIN;
7906         }
7907         conf->reshape_checkpoint = jiffies;
7908         md_wakeup_thread(mddev->sync_thread);
7909         md_new_event(mddev);
7910         return 0;
7911 }
7912
7913 /* This is called from the reshape thread and should make any
7914  * changes needed in 'conf'
7915  */
7916 static void end_reshape(struct r5conf *conf)
7917 {
7918
7919         if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
7920                 struct md_rdev *rdev;
7921
7922                 spin_lock_irq(&conf->device_lock);
7923                 conf->previous_raid_disks = conf->raid_disks;
7924                 rdev_for_each(rdev, conf->mddev)
7925                         rdev->data_offset = rdev->new_data_offset;
7926                 smp_wmb();
7927                 conf->reshape_progress = MaxSector;
7928                 conf->mddev->reshape_position = MaxSector;
7929                 spin_unlock_irq(&conf->device_lock);
7930                 wake_up(&conf->wait_for_overlap);
7931
7932                 /* read-ahead size must cover two whole stripes, which is
7933                  * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
7934                  */
7935                 if (conf->mddev->queue) {
7936                         int data_disks = conf->raid_disks - conf->max_degraded;
7937                         int stripe = data_disks * ((conf->chunk_sectors << 9)
7938                                                    / PAGE_SIZE);
7939                         if (conf->mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
7940                                 conf->mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
7941                 }
7942         }
7943 }
7944
7945 /* This is called from the raid5d thread with mddev_lock held.
7946  * It makes config changes to the device.
7947  */
7948 static void raid5_finish_reshape(struct mddev *mddev)
7949 {
7950         struct r5conf *conf = mddev->private;
7951
7952         if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
7953
7954                 if (mddev->delta_disks > 0) {
7955                         md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
7956                         if (mddev->queue) {
7957                                 set_capacity(mddev->gendisk, mddev->array_sectors);
7958                                 revalidate_disk(mddev->gendisk);
7959                         }
7960                 } else {
7961                         int d;
7962                         spin_lock_irq(&conf->device_lock);
7963                         mddev->degraded = raid5_calc_degraded(conf);
7964                         spin_unlock_irq(&conf->device_lock);
7965                         for (d = conf->raid_disks ;
7966                              d < conf->raid_disks - mddev->delta_disks;
7967                              d++) {
7968                                 struct md_rdev *rdev = conf->disks[d].rdev;
7969                                 if (rdev)
7970                                         clear_bit(In_sync, &rdev->flags);
7971                                 rdev = conf->disks[d].replacement;
7972                                 if (rdev)
7973                                         clear_bit(In_sync, &rdev->flags);
7974                         }
7975                 }
7976                 mddev->layout = conf->algorithm;
7977                 mddev->chunk_sectors = conf->chunk_sectors;
7978                 mddev->reshape_position = MaxSector;
7979                 mddev->delta_disks = 0;
7980                 mddev->reshape_backwards = 0;
7981         }
7982 }
7983
7984 static void raid5_quiesce(struct mddev *mddev, int state)
7985 {
7986         struct r5conf *conf = mddev->private;
7987
7988         switch(state) {
7989         case 2: /* resume for a suspend */
7990                 wake_up(&conf->wait_for_overlap);
7991                 break;
7992
7993         case 1: /* stop all writes */
7994                 lock_all_device_hash_locks_irq(conf);
7995                 /* '2' tells resync/reshape to pause so that all
7996                  * active stripes can drain
7997                  */
7998                 r5c_flush_cache(conf, INT_MAX);
7999                 conf->quiesce = 2;
8000                 wait_event_cmd(conf->wait_for_quiescent,
8001                                     atomic_read(&conf->active_stripes) == 0 &&
8002                                     atomic_read(&conf->active_aligned_reads) == 0,
8003                                     unlock_all_device_hash_locks_irq(conf),
8004                                     lock_all_device_hash_locks_irq(conf));
8005                 conf->quiesce = 1;
8006                 unlock_all_device_hash_locks_irq(conf);
8007                 /* allow reshape to continue */
8008                 wake_up(&conf->wait_for_overlap);
8009                 break;
8010
8011         case 0: /* re-enable writes */
8012                 lock_all_device_hash_locks_irq(conf);
8013                 conf->quiesce = 0;
8014                 wake_up(&conf->wait_for_quiescent);
8015                 wake_up(&conf->wait_for_overlap);
8016                 unlock_all_device_hash_locks_irq(conf);
8017                 break;
8018         }
8019         r5l_quiesce(conf->log, state);
8020 }
8021
8022 static void *raid45_takeover_raid0(struct mddev *mddev, int level)
8023 {
8024         struct r0conf *raid0_conf = mddev->private;
8025         sector_t sectors;
8026
8027         /* for raid0 takeover only one zone is supported */
8028         if (raid0_conf->nr_strip_zones > 1) {
8029                 pr_warn("md/raid:%s: cannot takeover raid0 with more than one zone.\n",
8030                         mdname(mddev));
8031                 return ERR_PTR(-EINVAL);
8032         }
8033
8034         sectors = raid0_conf->strip_zone[0].zone_end;
8035         sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
8036         mddev->dev_sectors = sectors;
8037         mddev->new_level = level;
8038         mddev->new_layout = ALGORITHM_PARITY_N;
8039         mddev->new_chunk_sectors = mddev->chunk_sectors;
8040         mddev->raid_disks += 1;
8041         mddev->delta_disks = 1;
8042         /* make sure it will be not marked as dirty */
8043         mddev->recovery_cp = MaxSector;
8044
8045         return setup_conf(mddev);
8046 }
8047
8048 static void *raid5_takeover_raid1(struct mddev *mddev)
8049 {
8050         int chunksect;
8051         void *ret;
8052
8053         if (mddev->raid_disks != 2 ||
8054             mddev->degraded > 1)
8055                 return ERR_PTR(-EINVAL);
8056
8057         /* Should check if there are write-behind devices? */
8058
8059         chunksect = 64*2; /* 64K by default */
8060
8061         /* The array must be an exact multiple of chunksize */
8062         while (chunksect && (mddev->array_sectors & (chunksect-1)))
8063                 chunksect >>= 1;
8064
8065         if ((chunksect<<9) < STRIPE_SIZE)
8066                 /* array size does not allow a suitable chunk size */
8067                 return ERR_PTR(-EINVAL);
8068
8069         mddev->new_level = 5;
8070         mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
8071         mddev->new_chunk_sectors = chunksect;
8072
8073         ret = setup_conf(mddev);
8074         if (!IS_ERR(ret))
8075                 mddev_clear_unsupported_flags(mddev,
8076                         UNSUPPORTED_MDDEV_FLAGS);
8077         return ret;
8078 }
8079
8080 static void *raid5_takeover_raid6(struct mddev *mddev)
8081 {
8082         int new_layout;
8083
8084         switch (mddev->layout) {
8085         case ALGORITHM_LEFT_ASYMMETRIC_6:
8086                 new_layout = ALGORITHM_LEFT_ASYMMETRIC;
8087                 break;
8088         case ALGORITHM_RIGHT_ASYMMETRIC_6:
8089                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
8090                 break;
8091         case ALGORITHM_LEFT_SYMMETRIC_6:
8092                 new_layout = ALGORITHM_LEFT_SYMMETRIC;
8093                 break;
8094         case ALGORITHM_RIGHT_SYMMETRIC_6:
8095                 new_layout = ALGORITHM_RIGHT_SYMMETRIC;
8096                 break;
8097         case ALGORITHM_PARITY_0_6:
8098                 new_layout = ALGORITHM_PARITY_0;
8099                 break;
8100         case ALGORITHM_PARITY_N:
8101                 new_layout = ALGORITHM_PARITY_N;
8102                 break;
8103         default:
8104                 return ERR_PTR(-EINVAL);
8105         }
8106         mddev->new_level = 5;
8107         mddev->new_layout = new_layout;
8108         mddev->delta_disks = -1;
8109         mddev->raid_disks -= 1;
8110         return setup_conf(mddev);
8111 }
8112
8113 static int raid5_check_reshape(struct mddev *mddev)
8114 {
8115         /* For a 2-drive array, the layout and chunk size can be changed
8116          * immediately as not restriping is needed.
8117          * For larger arrays we record the new value - after validation
8118          * to be used by a reshape pass.
8119          */
8120         struct r5conf *conf = mddev->private;
8121         int new_chunk = mddev->new_chunk_sectors;
8122
8123         if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
8124                 return -EINVAL;
8125         if (new_chunk > 0) {
8126                 if (!is_power_of_2(new_chunk))
8127                         return -EINVAL;
8128                 if (new_chunk < (PAGE_SIZE>>9))
8129                         return -EINVAL;
8130                 if (mddev->array_sectors & (new_chunk-1))
8131                         /* not factor of array size */
8132                         return -EINVAL;
8133         }
8134
8135         /* They look valid */
8136
8137         if (mddev->raid_disks == 2) {
8138                 /* can make the change immediately */
8139                 if (mddev->new_layout >= 0) {
8140                         conf->algorithm = mddev->new_layout;
8141                         mddev->layout = mddev->new_layout;
8142                 }
8143                 if (new_chunk > 0) {
8144                         conf->chunk_sectors = new_chunk ;
8145                         mddev->chunk_sectors = new_chunk;
8146                 }
8147                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8148                 md_wakeup_thread(mddev->thread);
8149         }
8150         return check_reshape(mddev);
8151 }
8152
8153 static int raid6_check_reshape(struct mddev *mddev)
8154 {
8155         int new_chunk = mddev->new_chunk_sectors;
8156
8157         if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
8158                 return -EINVAL;
8159         if (new_chunk > 0) {
8160                 if (!is_power_of_2(new_chunk))
8161                         return -EINVAL;
8162                 if (new_chunk < (PAGE_SIZE >> 9))
8163                         return -EINVAL;
8164                 if (mddev->array_sectors & (new_chunk-1))
8165                         /* not factor of array size */
8166                         return -EINVAL;
8167         }
8168
8169         /* They look valid */
8170         return check_reshape(mddev);
8171 }
8172
8173 static void *raid5_takeover(struct mddev *mddev)
8174 {
8175         /* raid5 can take over:
8176          *  raid0 - if there is only one strip zone - make it a raid4 layout
8177          *  raid1 - if there are two drives.  We need to know the chunk size
8178          *  raid4 - trivial - just use a raid4 layout.
8179          *  raid6 - Providing it is a *_6 layout
8180          */
8181         if (mddev->level == 0)
8182                 return raid45_takeover_raid0(mddev, 5);
8183         if (mddev->level == 1)
8184                 return raid5_takeover_raid1(mddev);
8185         if (mddev->level == 4) {
8186                 mddev->new_layout = ALGORITHM_PARITY_N;
8187                 mddev->new_level = 5;
8188                 return setup_conf(mddev);
8189         }
8190         if (mddev->level == 6)
8191                 return raid5_takeover_raid6(mddev);
8192
8193         return ERR_PTR(-EINVAL);
8194 }
8195
8196 static void *raid4_takeover(struct mddev *mddev)
8197 {
8198         /* raid4 can take over:
8199          *  raid0 - if there is only one strip zone
8200          *  raid5 - if layout is right
8201          */
8202         if (mddev->level == 0)
8203                 return raid45_takeover_raid0(mddev, 4);
8204         if (mddev->level == 5 &&
8205             mddev->layout == ALGORITHM_PARITY_N) {
8206                 mddev->new_layout = 0;
8207                 mddev->new_level = 4;
8208                 return setup_conf(mddev);
8209         }
8210         return ERR_PTR(-EINVAL);
8211 }
8212
8213 static struct md_personality raid5_personality;
8214
8215 static void *raid6_takeover(struct mddev *mddev)
8216 {
8217         /* Currently can only take over a raid5.  We map the
8218          * personality to an equivalent raid6 personality
8219          * with the Q block at the end.
8220          */
8221         int new_layout;
8222
8223         if (mddev->pers != &raid5_personality)
8224                 return ERR_PTR(-EINVAL);
8225         if (mddev->degraded > 1)
8226                 return ERR_PTR(-EINVAL);
8227         if (mddev->raid_disks > 253)
8228                 return ERR_PTR(-EINVAL);
8229         if (mddev->raid_disks < 3)
8230                 return ERR_PTR(-EINVAL);
8231
8232         switch (mddev->layout) {
8233         case ALGORITHM_LEFT_ASYMMETRIC:
8234                 new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
8235                 break;
8236         case ALGORITHM_RIGHT_ASYMMETRIC:
8237                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
8238                 break;
8239         case ALGORITHM_LEFT_SYMMETRIC:
8240                 new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
8241                 break;
8242         case ALGORITHM_RIGHT_SYMMETRIC:
8243                 new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
8244                 break;
8245         case ALGORITHM_PARITY_0:
8246                 new_layout = ALGORITHM_PARITY_0_6;
8247                 break;
8248         case ALGORITHM_PARITY_N:
8249                 new_layout = ALGORITHM_PARITY_N;
8250                 break;
8251         default:
8252                 return ERR_PTR(-EINVAL);
8253         }
8254         mddev->new_level = 6;
8255         mddev->new_layout = new_layout;
8256         mddev->delta_disks = 1;
8257         mddev->raid_disks += 1;
8258         return setup_conf(mddev);
8259 }
8260
8261 static int raid5_change_consistency_policy(struct mddev *mddev, const char *buf)
8262 {
8263         struct r5conf *conf;
8264         int err;
8265
8266         err = mddev_lock(mddev);
8267         if (err)
8268                 return err;
8269         conf = mddev->private;
8270         if (!conf) {
8271                 mddev_unlock(mddev);
8272                 return -ENODEV;
8273         }
8274
8275         if (strncmp(buf, "ppl", 3) == 0) {
8276                 /* ppl only works with RAID 5 */
8277                 if (!raid5_has_ppl(conf) && conf->level == 5) {
8278                         err = log_init(conf, NULL, true);
8279                         if (!err) {
8280                                 err = resize_stripes(conf, conf->pool_size);
8281                                 if (err)
8282                                         log_exit(conf);
8283                         }
8284                 } else
8285                         err = -EINVAL;
8286         } else if (strncmp(buf, "resync", 6) == 0) {
8287                 if (raid5_has_ppl(conf)) {
8288                         mddev_suspend(mddev);
8289                         log_exit(conf);
8290                         mddev_resume(mddev);
8291                         err = resize_stripes(conf, conf->pool_size);
8292                 } else if (test_bit(MD_HAS_JOURNAL, &conf->mddev->flags) &&
8293                            r5l_log_disk_error(conf)) {
8294                         bool journal_dev_exists = false;
8295                         struct md_rdev *rdev;
8296
8297                         rdev_for_each(rdev, mddev)
8298                                 if (test_bit(Journal, &rdev->flags)) {
8299                                         journal_dev_exists = true;
8300                                         break;
8301                                 }
8302
8303                         if (!journal_dev_exists) {
8304                                 mddev_suspend(mddev);
8305                                 clear_bit(MD_HAS_JOURNAL, &mddev->flags);
8306                                 mddev_resume(mddev);
8307                         } else  /* need remove journal device first */
8308                                 err = -EBUSY;
8309                 } else
8310                         err = -EINVAL;
8311         } else {
8312                 err = -EINVAL;
8313         }
8314
8315         if (!err)
8316                 md_update_sb(mddev, 1);
8317
8318         mddev_unlock(mddev);
8319
8320         return err;
8321 }
8322
8323 static struct md_personality raid6_personality =
8324 {
8325         .name           = "raid6",
8326         .level          = 6,
8327         .owner          = THIS_MODULE,
8328         .make_request   = raid5_make_request,
8329         .run            = raid5_run,
8330         .free           = raid5_free,
8331         .status         = raid5_status,
8332         .error_handler  = raid5_error,
8333         .hot_add_disk   = raid5_add_disk,
8334         .hot_remove_disk= raid5_remove_disk,
8335         .spare_active   = raid5_spare_active,
8336         .sync_request   = raid5_sync_request,
8337         .resize         = raid5_resize,
8338         .size           = raid5_size,
8339         .check_reshape  = raid6_check_reshape,
8340         .start_reshape  = raid5_start_reshape,
8341         .finish_reshape = raid5_finish_reshape,
8342         .quiesce        = raid5_quiesce,
8343         .takeover       = raid6_takeover,
8344         .congested      = raid5_congested,
8345         .change_consistency_policy = raid5_change_consistency_policy,
8346 };
8347 static struct md_personality raid5_personality =
8348 {
8349         .name           = "raid5",
8350         .level          = 5,
8351         .owner          = THIS_MODULE,
8352         .make_request   = raid5_make_request,
8353         .run            = raid5_run,
8354         .free           = raid5_free,
8355         .status         = raid5_status,
8356         .error_handler  = raid5_error,
8357         .hot_add_disk   = raid5_add_disk,
8358         .hot_remove_disk= raid5_remove_disk,
8359         .spare_active   = raid5_spare_active,
8360         .sync_request   = raid5_sync_request,
8361         .resize         = raid5_resize,
8362         .size           = raid5_size,
8363         .check_reshape  = raid5_check_reshape,
8364         .start_reshape  = raid5_start_reshape,
8365         .finish_reshape = raid5_finish_reshape,
8366         .quiesce        = raid5_quiesce,
8367         .takeover       = raid5_takeover,
8368         .congested      = raid5_congested,
8369         .change_consistency_policy = raid5_change_consistency_policy,
8370 };
8371
8372 static struct md_personality raid4_personality =
8373 {
8374         .name           = "raid4",
8375         .level          = 4,
8376         .owner          = THIS_MODULE,
8377         .make_request   = raid5_make_request,
8378         .run            = raid5_run,
8379         .free           = raid5_free,
8380         .status         = raid5_status,
8381         .error_handler  = raid5_error,
8382         .hot_add_disk   = raid5_add_disk,
8383         .hot_remove_disk= raid5_remove_disk,
8384         .spare_active   = raid5_spare_active,
8385         .sync_request   = raid5_sync_request,
8386         .resize         = raid5_resize,
8387         .size           = raid5_size,
8388         .check_reshape  = raid5_check_reshape,
8389         .start_reshape  = raid5_start_reshape,
8390         .finish_reshape = raid5_finish_reshape,
8391         .quiesce        = raid5_quiesce,
8392         .takeover       = raid4_takeover,
8393         .congested      = raid5_congested,
8394         .change_consistency_policy = raid5_change_consistency_policy,
8395 };
8396
8397 static int __init raid5_init(void)
8398 {
8399         int ret;
8400
8401         raid5_wq = alloc_workqueue("raid5wq",
8402                 WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE|WQ_SYSFS, 0);
8403         if (!raid5_wq)
8404                 return -ENOMEM;
8405
8406         ret = cpuhp_setup_state_multi(CPUHP_MD_RAID5_PREPARE,
8407                                       "md/raid5:prepare",
8408                                       raid456_cpu_up_prepare,
8409                                       raid456_cpu_dead);
8410         if (ret) {
8411                 destroy_workqueue(raid5_wq);
8412                 return ret;
8413         }
8414         register_md_personality(&raid6_personality);
8415         register_md_personality(&raid5_personality);
8416         register_md_personality(&raid4_personality);
8417         return 0;
8418 }
8419
8420 static void raid5_exit(void)
8421 {
8422         unregister_md_personality(&raid6_personality);
8423         unregister_md_personality(&raid5_personality);
8424         unregister_md_personality(&raid4_personality);
8425         cpuhp_remove_multi_state(CPUHP_MD_RAID5_PREPARE);
8426         destroy_workqueue(raid5_wq);
8427 }
8428
8429 module_init(raid5_init);
8430 module_exit(raid5_exit);
8431 MODULE_LICENSE("GPL");
8432 MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
8433 MODULE_ALIAS("md-personality-4"); /* RAID5 */
8434 MODULE_ALIAS("md-raid5");
8435 MODULE_ALIAS("md-raid4");
8436 MODULE_ALIAS("md-level-5");
8437 MODULE_ALIAS("md-level-4");
8438 MODULE_ALIAS("md-personality-8"); /* RAID6 */
8439 MODULE_ALIAS("md-raid6");
8440 MODULE_ALIAS("md-level-6");
8441
8442 /* This used to be two separate modules, they were: */
8443 MODULE_ALIAS("raid5");
8444 MODULE_ALIAS("raid6");