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