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
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!
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)
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.
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
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
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
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
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 <trace/events/block.h>
64 #define cpu_to_group(cpu) cpu_to_node(cpu)
65 #define ANY_GROUP NUMA_NO_NODE
67 static struct workqueue_struct
*raid5_wq
;
72 #define NR_STRIPES 256
73 #define STRIPE_SIZE PAGE_SIZE
74 #define STRIPE_SHIFT (PAGE_SHIFT - 9)
75 #define STRIPE_SECTORS (STRIPE_SIZE>>9)
76 #define IO_THRESHOLD 1
77 #define BYPASS_THRESHOLD 1
78 #define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head))
79 #define HASH_MASK (NR_HASH - 1)
80 #define MAX_STRIPE_BATCH 8
82 static inline struct hlist_head
*stripe_hash(struct r5conf
*conf
, sector_t sect
)
84 int hash
= (sect
>> STRIPE_SHIFT
) & HASH_MASK
;
85 return &conf
->stripe_hashtbl
[hash
];
88 /* bio's attached to a stripe+device for I/O are linked together in bi_sector
89 * order without overlap. There may be several bio's per stripe+device, and
90 * a bio could span several devices.
91 * When walking this list for a particular stripe+device, we must never proceed
92 * beyond a bio that extends past this device, as the next bio might no longer
94 * This function is used to determine the 'next' bio in the list, given the sector
95 * of the current stripe+device
97 static inline struct bio
*r5_next_bio(struct bio
*bio
, sector_t sector
)
99 int sectors
= bio_sectors(bio
);
100 if (bio
->bi_sector
+ sectors
< sector
+ STRIPE_SECTORS
)
107 * We maintain a biased count of active stripes in the bottom 16 bits of
108 * bi_phys_segments, and a count of processed stripes in the upper 16 bits
110 static inline int raid5_bi_processed_stripes(struct bio
*bio
)
112 atomic_t
*segments
= (atomic_t
*)&bio
->bi_phys_segments
;
113 return (atomic_read(segments
) >> 16) & 0xffff;
116 static inline int raid5_dec_bi_active_stripes(struct bio
*bio
)
118 atomic_t
*segments
= (atomic_t
*)&bio
->bi_phys_segments
;
119 return atomic_sub_return(1, segments
) & 0xffff;
122 static inline void raid5_inc_bi_active_stripes(struct bio
*bio
)
124 atomic_t
*segments
= (atomic_t
*)&bio
->bi_phys_segments
;
125 atomic_inc(segments
);
128 static inline void raid5_set_bi_processed_stripes(struct bio
*bio
,
131 atomic_t
*segments
= (atomic_t
*)&bio
->bi_phys_segments
;
135 old
= atomic_read(segments
);
136 new = (old
& 0xffff) | (cnt
<< 16);
137 } while (atomic_cmpxchg(segments
, old
, new) != old
);
140 static inline void raid5_set_bi_stripes(struct bio
*bio
, unsigned int cnt
)
142 atomic_t
*segments
= (atomic_t
*)&bio
->bi_phys_segments
;
143 atomic_set(segments
, cnt
);
146 /* Find first data disk in a raid6 stripe */
147 static inline int raid6_d0(struct stripe_head
*sh
)
150 /* ddf always start from first device */
152 /* md starts just after Q block */
153 if (sh
->qd_idx
== sh
->disks
- 1)
156 return sh
->qd_idx
+ 1;
158 static inline int raid6_next_disk(int disk
, int raid_disks
)
161 return (disk
< raid_disks
) ? disk
: 0;
164 /* When walking through the disks in a raid5, starting at raid6_d0,
165 * We need to map each disk to a 'slot', where the data disks are slot
166 * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
167 * is raid_disks-1. This help does that mapping.
169 static int raid6_idx_to_slot(int idx
, struct stripe_head
*sh
,
170 int *count
, int syndrome_disks
)
176 if (idx
== sh
->pd_idx
)
177 return syndrome_disks
;
178 if (idx
== sh
->qd_idx
)
179 return syndrome_disks
+ 1;
185 static void return_io(struct bio
*return_bi
)
187 struct bio
*bi
= return_bi
;
190 return_bi
= bi
->bi_next
;
193 trace_block_bio_complete(bdev_get_queue(bi
->bi_bdev
),
200 static void print_raid5_conf (struct r5conf
*conf
);
202 static int stripe_operations_active(struct stripe_head
*sh
)
204 return sh
->check_state
|| sh
->reconstruct_state
||
205 test_bit(STRIPE_BIOFILL_RUN
, &sh
->state
) ||
206 test_bit(STRIPE_COMPUTE_RUN
, &sh
->state
);
209 static void raid5_wakeup_stripe_thread(struct stripe_head
*sh
)
211 struct r5conf
*conf
= sh
->raid_conf
;
212 struct r5worker_group
*group
;
214 int i
, cpu
= sh
->cpu
;
216 if (!cpu_online(cpu
)) {
217 cpu
= cpumask_any(cpu_online_mask
);
221 if (list_empty(&sh
->lru
)) {
222 struct r5worker_group
*group
;
223 group
= conf
->worker_groups
+ cpu_to_group(cpu
);
224 list_add_tail(&sh
->lru
, &group
->handle_list
);
225 group
->stripes_cnt
++;
229 if (conf
->worker_cnt_per_group
== 0) {
230 md_wakeup_thread(conf
->mddev
->thread
);
234 group
= conf
->worker_groups
+ cpu_to_group(sh
->cpu
);
236 group
->workers
[0].working
= true;
237 /* at least one worker should run to avoid race */
238 queue_work_on(sh
->cpu
, raid5_wq
, &group
->workers
[0].work
);
240 thread_cnt
= group
->stripes_cnt
/ MAX_STRIPE_BATCH
- 1;
241 /* wakeup more workers */
242 for (i
= 1; i
< conf
->worker_cnt_per_group
&& thread_cnt
> 0; i
++) {
243 if (group
->workers
[i
].working
== false) {
244 group
->workers
[i
].working
= true;
245 queue_work_on(sh
->cpu
, raid5_wq
,
246 &group
->workers
[i
].work
);
252 static void do_release_stripe(struct r5conf
*conf
, struct stripe_head
*sh
)
254 BUG_ON(!list_empty(&sh
->lru
));
255 BUG_ON(atomic_read(&conf
->active_stripes
)==0);
256 if (test_bit(STRIPE_HANDLE
, &sh
->state
)) {
257 if (test_bit(STRIPE_DELAYED
, &sh
->state
) &&
258 !test_bit(STRIPE_PREREAD_ACTIVE
, &sh
->state
))
259 list_add_tail(&sh
->lru
, &conf
->delayed_list
);
260 else if (test_bit(STRIPE_BIT_DELAY
, &sh
->state
) &&
261 sh
->bm_seq
- conf
->seq_write
> 0)
262 list_add_tail(&sh
->lru
, &conf
->bitmap_list
);
264 clear_bit(STRIPE_DELAYED
, &sh
->state
);
265 clear_bit(STRIPE_BIT_DELAY
, &sh
->state
);
266 if (conf
->worker_cnt_per_group
== 0) {
267 list_add_tail(&sh
->lru
, &conf
->handle_list
);
269 raid5_wakeup_stripe_thread(sh
);
273 md_wakeup_thread(conf
->mddev
->thread
);
275 BUG_ON(stripe_operations_active(sh
));
276 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE
, &sh
->state
))
277 if (atomic_dec_return(&conf
->preread_active_stripes
)
279 md_wakeup_thread(conf
->mddev
->thread
);
280 atomic_dec(&conf
->active_stripes
);
281 if (!test_bit(STRIPE_EXPANDING
, &sh
->state
)) {
282 list_add_tail(&sh
->lru
, &conf
->inactive_list
);
283 wake_up(&conf
->wait_for_stripe
);
284 if (conf
->retry_read_aligned
)
285 md_wakeup_thread(conf
->mddev
->thread
);
290 static void __release_stripe(struct r5conf
*conf
, struct stripe_head
*sh
)
292 if (atomic_dec_and_test(&sh
->count
))
293 do_release_stripe(conf
, sh
);
296 static struct llist_node
*llist_reverse_order(struct llist_node
*head
)
298 struct llist_node
*new_head
= NULL
;
301 struct llist_node
*tmp
= head
;
303 tmp
->next
= new_head
;
310 /* should hold conf->device_lock already */
311 static int release_stripe_list(struct r5conf
*conf
)
313 struct stripe_head
*sh
;
315 struct llist_node
*head
;
317 head
= llist_del_all(&conf
->released_stripes
);
318 head
= llist_reverse_order(head
);
320 sh
= llist_entry(head
, struct stripe_head
, release_list
);
321 head
= llist_next(head
);
322 /* sh could be readded after STRIPE_ON_RELEASE_LIST is cleard */
324 clear_bit(STRIPE_ON_RELEASE_LIST
, &sh
->state
);
326 * Don't worry the bit is set here, because if the bit is set
327 * again, the count is always > 1. This is true for
328 * STRIPE_ON_UNPLUG_LIST bit too.
330 __release_stripe(conf
, sh
);
337 static void release_stripe(struct stripe_head
*sh
)
339 struct r5conf
*conf
= sh
->raid_conf
;
343 if (test_and_set_bit(STRIPE_ON_RELEASE_LIST
, &sh
->state
))
345 wakeup
= llist_add(&sh
->release_list
, &conf
->released_stripes
);
347 md_wakeup_thread(conf
->mddev
->thread
);
350 local_irq_save(flags
);
351 /* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */
352 if (atomic_dec_and_lock(&sh
->count
, &conf
->device_lock
)) {
353 do_release_stripe(conf
, sh
);
354 spin_unlock(&conf
->device_lock
);
356 local_irq_restore(flags
);
359 static inline void remove_hash(struct stripe_head
*sh
)
361 pr_debug("remove_hash(), stripe %llu\n",
362 (unsigned long long)sh
->sector
);
364 hlist_del_init(&sh
->hash
);
367 static inline void insert_hash(struct r5conf
*conf
, struct stripe_head
*sh
)
369 struct hlist_head
*hp
= stripe_hash(conf
, sh
->sector
);
371 pr_debug("insert_hash(), stripe %llu\n",
372 (unsigned long long)sh
->sector
);
374 hlist_add_head(&sh
->hash
, hp
);
378 /* find an idle stripe, make sure it is unhashed, and return it. */
379 static struct stripe_head
*get_free_stripe(struct r5conf
*conf
)
381 struct stripe_head
*sh
= NULL
;
382 struct list_head
*first
;
384 if (list_empty(&conf
->inactive_list
))
386 first
= conf
->inactive_list
.next
;
387 sh
= list_entry(first
, struct stripe_head
, lru
);
388 list_del_init(first
);
390 atomic_inc(&conf
->active_stripes
);
395 static void shrink_buffers(struct stripe_head
*sh
)
399 int num
= sh
->raid_conf
->pool_size
;
401 for (i
= 0; i
< num
; i
++) {
405 sh
->dev
[i
].page
= NULL
;
410 static int grow_buffers(struct stripe_head
*sh
)
413 int num
= sh
->raid_conf
->pool_size
;
415 for (i
= 0; i
< num
; i
++) {
418 if (!(page
= alloc_page(GFP_KERNEL
))) {
421 sh
->dev
[i
].page
= page
;
426 static void raid5_build_block(struct stripe_head
*sh
, int i
, int previous
);
427 static void stripe_set_idx(sector_t stripe
, struct r5conf
*conf
, int previous
,
428 struct stripe_head
*sh
);
430 static void init_stripe(struct stripe_head
*sh
, sector_t sector
, int previous
)
432 struct r5conf
*conf
= sh
->raid_conf
;
435 BUG_ON(atomic_read(&sh
->count
) != 0);
436 BUG_ON(test_bit(STRIPE_HANDLE
, &sh
->state
));
437 BUG_ON(stripe_operations_active(sh
));
439 pr_debug("init_stripe called, stripe %llu\n",
440 (unsigned long long)sh
->sector
);
444 sh
->generation
= conf
->generation
- previous
;
445 sh
->disks
= previous
? conf
->previous_raid_disks
: conf
->raid_disks
;
447 stripe_set_idx(sector
, conf
, previous
, sh
);
451 for (i
= sh
->disks
; i
--; ) {
452 struct r5dev
*dev
= &sh
->dev
[i
];
454 if (dev
->toread
|| dev
->read
|| dev
->towrite
|| dev
->written
||
455 test_bit(R5_LOCKED
, &dev
->flags
)) {
456 printk(KERN_ERR
"sector=%llx i=%d %p %p %p %p %d\n",
457 (unsigned long long)sh
->sector
, i
, dev
->toread
,
458 dev
->read
, dev
->towrite
, dev
->written
,
459 test_bit(R5_LOCKED
, &dev
->flags
));
463 raid5_build_block(sh
, i
, previous
);
465 insert_hash(conf
, sh
);
466 sh
->cpu
= smp_processor_id();
469 static struct stripe_head
*__find_stripe(struct r5conf
*conf
, sector_t sector
,
472 struct stripe_head
*sh
;
474 pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector
);
475 hlist_for_each_entry(sh
, stripe_hash(conf
, sector
), hash
)
476 if (sh
->sector
== sector
&& sh
->generation
== generation
)
478 pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector
);
483 * Need to check if array has failed when deciding whether to:
485 * - remove non-faulty devices
488 * This determination is simple when no reshape is happening.
489 * However if there is a reshape, we need to carefully check
490 * both the before and after sections.
491 * This is because some failed devices may only affect one
492 * of the two sections, and some non-in_sync devices may
493 * be insync in the section most affected by failed devices.
495 static int calc_degraded(struct r5conf
*conf
)
497 int degraded
, degraded2
;
502 for (i
= 0; i
< conf
->previous_raid_disks
; i
++) {
503 struct md_rdev
*rdev
= rcu_dereference(conf
->disks
[i
].rdev
);
504 if (rdev
&& test_bit(Faulty
, &rdev
->flags
))
505 rdev
= rcu_dereference(conf
->disks
[i
].replacement
);
506 if (!rdev
|| test_bit(Faulty
, &rdev
->flags
))
508 else if (test_bit(In_sync
, &rdev
->flags
))
511 /* not in-sync or faulty.
512 * If the reshape increases the number of devices,
513 * this is being recovered by the reshape, so
514 * this 'previous' section is not in_sync.
515 * If the number of devices is being reduced however,
516 * the device can only be part of the array if
517 * we are reverting a reshape, so this section will
520 if (conf
->raid_disks
>= conf
->previous_raid_disks
)
524 if (conf
->raid_disks
== conf
->previous_raid_disks
)
528 for (i
= 0; i
< conf
->raid_disks
; i
++) {
529 struct md_rdev
*rdev
= rcu_dereference(conf
->disks
[i
].rdev
);
530 if (rdev
&& test_bit(Faulty
, &rdev
->flags
))
531 rdev
= rcu_dereference(conf
->disks
[i
].replacement
);
532 if (!rdev
|| test_bit(Faulty
, &rdev
->flags
))
534 else if (test_bit(In_sync
, &rdev
->flags
))
537 /* not in-sync or faulty.
538 * If reshape increases the number of devices, this
539 * section has already been recovered, else it
540 * almost certainly hasn't.
542 if (conf
->raid_disks
<= conf
->previous_raid_disks
)
546 if (degraded2
> degraded
)
551 static int has_failed(struct r5conf
*conf
)
555 if (conf
->mddev
->reshape_position
== MaxSector
)
556 return conf
->mddev
->degraded
> conf
->max_degraded
;
558 degraded
= calc_degraded(conf
);
559 if (degraded
> conf
->max_degraded
)
564 static struct stripe_head
*
565 get_active_stripe(struct r5conf
*conf
, sector_t sector
,
566 int previous
, int noblock
, int noquiesce
)
568 struct stripe_head
*sh
;
570 pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector
);
572 spin_lock_irq(&conf
->device_lock
);
575 wait_event_lock_irq(conf
->wait_for_stripe
,
576 conf
->quiesce
== 0 || noquiesce
,
578 sh
= __find_stripe(conf
, sector
, conf
->generation
- previous
);
580 if (!conf
->inactive_blocked
)
581 sh
= get_free_stripe(conf
);
582 if (noblock
&& sh
== NULL
)
585 conf
->inactive_blocked
= 1;
586 wait_event_lock_irq(conf
->wait_for_stripe
,
587 !list_empty(&conf
->inactive_list
) &&
588 (atomic_read(&conf
->active_stripes
)
589 < (conf
->max_nr_stripes
*3/4)
590 || !conf
->inactive_blocked
),
592 conf
->inactive_blocked
= 0;
594 init_stripe(sh
, sector
, previous
);
596 if (atomic_read(&sh
->count
)) {
597 BUG_ON(!list_empty(&sh
->lru
)
598 && !test_bit(STRIPE_EXPANDING
, &sh
->state
)
599 && !test_bit(STRIPE_ON_UNPLUG_LIST
, &sh
->state
)
600 && !test_bit(STRIPE_ON_RELEASE_LIST
, &sh
->state
));
602 if (!test_bit(STRIPE_HANDLE
, &sh
->state
))
603 atomic_inc(&conf
->active_stripes
);
604 if (list_empty(&sh
->lru
) &&
605 !test_bit(STRIPE_EXPANDING
, &sh
->state
))
607 list_del_init(&sh
->lru
);
609 sh
->group
->stripes_cnt
--;
614 } while (sh
== NULL
);
617 atomic_inc(&sh
->count
);
619 spin_unlock_irq(&conf
->device_lock
);
623 /* Determine if 'data_offset' or 'new_data_offset' should be used
624 * in this stripe_head.
626 static int use_new_offset(struct r5conf
*conf
, struct stripe_head
*sh
)
628 sector_t progress
= conf
->reshape_progress
;
629 /* Need a memory barrier to make sure we see the value
630 * of conf->generation, or ->data_offset that was set before
631 * reshape_progress was updated.
634 if (progress
== MaxSector
)
636 if (sh
->generation
== conf
->generation
- 1)
638 /* We are in a reshape, and this is a new-generation stripe,
639 * so use new_data_offset.
645 raid5_end_read_request(struct bio
*bi
, int error
);
647 raid5_end_write_request(struct bio
*bi
, int error
);
649 static void ops_run_io(struct stripe_head
*sh
, struct stripe_head_state
*s
)
651 struct r5conf
*conf
= sh
->raid_conf
;
652 int i
, disks
= sh
->disks
;
656 for (i
= disks
; i
--; ) {
658 int replace_only
= 0;
659 struct bio
*bi
, *rbi
;
660 struct md_rdev
*rdev
, *rrdev
= NULL
;
661 if (test_and_clear_bit(R5_Wantwrite
, &sh
->dev
[i
].flags
)) {
662 if (test_and_clear_bit(R5_WantFUA
, &sh
->dev
[i
].flags
))
666 if (test_bit(R5_Discard
, &sh
->dev
[i
].flags
))
668 } else if (test_and_clear_bit(R5_Wantread
, &sh
->dev
[i
].flags
))
670 else if (test_and_clear_bit(R5_WantReplace
,
671 &sh
->dev
[i
].flags
)) {
676 if (test_and_clear_bit(R5_SyncIO
, &sh
->dev
[i
].flags
))
679 bi
= &sh
->dev
[i
].req
;
680 rbi
= &sh
->dev
[i
].rreq
; /* For writing to replacement */
683 rrdev
= rcu_dereference(conf
->disks
[i
].replacement
);
684 smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
685 rdev
= rcu_dereference(conf
->disks
[i
].rdev
);
694 /* We raced and saw duplicates */
697 if (test_bit(R5_ReadRepl
, &sh
->dev
[i
].flags
) && rrdev
)
702 if (rdev
&& test_bit(Faulty
, &rdev
->flags
))
705 atomic_inc(&rdev
->nr_pending
);
706 if (rrdev
&& test_bit(Faulty
, &rrdev
->flags
))
709 atomic_inc(&rrdev
->nr_pending
);
712 /* We have already checked bad blocks for reads. Now
713 * need to check for writes. We never accept write errors
714 * on the replacement, so we don't to check rrdev.
716 while ((rw
& WRITE
) && rdev
&&
717 test_bit(WriteErrorSeen
, &rdev
->flags
)) {
720 int bad
= is_badblock(rdev
, sh
->sector
, STRIPE_SECTORS
,
721 &first_bad
, &bad_sectors
);
726 set_bit(BlockedBadBlocks
, &rdev
->flags
);
727 if (!conf
->mddev
->external
&&
728 conf
->mddev
->flags
) {
729 /* It is very unlikely, but we might
730 * still need to write out the
731 * bad block log - better give it
733 md_check_recovery(conf
->mddev
);
736 * Because md_wait_for_blocked_rdev
737 * will dec nr_pending, we must
738 * increment it first.
740 atomic_inc(&rdev
->nr_pending
);
741 md_wait_for_blocked_rdev(rdev
, conf
->mddev
);
743 /* Acknowledged bad block - skip the write */
744 rdev_dec_pending(rdev
, conf
->mddev
);
750 if (s
->syncing
|| s
->expanding
|| s
->expanded
752 md_sync_acct(rdev
->bdev
, STRIPE_SECTORS
);
754 set_bit(STRIPE_IO_STARTED
, &sh
->state
);
757 bi
->bi_bdev
= rdev
->bdev
;
759 bi
->bi_end_io
= (rw
& WRITE
)
760 ? raid5_end_write_request
761 : raid5_end_read_request
;
764 pr_debug("%s: for %llu schedule op %ld on disc %d\n",
765 __func__
, (unsigned long long)sh
->sector
,
767 atomic_inc(&sh
->count
);
768 if (use_new_offset(conf
, sh
))
769 bi
->bi_sector
= (sh
->sector
770 + rdev
->new_data_offset
);
772 bi
->bi_sector
= (sh
->sector
773 + rdev
->data_offset
);
774 if (test_bit(R5_ReadNoMerge
, &sh
->dev
[i
].flags
))
775 bi
->bi_rw
|= REQ_FLUSH
;
778 bi
->bi_io_vec
[0].bv_len
= STRIPE_SIZE
;
779 bi
->bi_io_vec
[0].bv_offset
= 0;
780 bi
->bi_size
= STRIPE_SIZE
;
782 * If this is discard request, set bi_vcnt 0. We don't
783 * want to confuse SCSI because SCSI will replace payload
785 if (rw
& REQ_DISCARD
)
788 set_bit(R5_DOUBLE_LOCKED
, &sh
->dev
[i
].flags
);
790 if (conf
->mddev
->gendisk
)
791 trace_block_bio_remap(bdev_get_queue(bi
->bi_bdev
),
792 bi
, disk_devt(conf
->mddev
->gendisk
),
794 generic_make_request(bi
);
797 if (s
->syncing
|| s
->expanding
|| s
->expanded
799 md_sync_acct(rrdev
->bdev
, STRIPE_SECTORS
);
801 set_bit(STRIPE_IO_STARTED
, &sh
->state
);
804 rbi
->bi_bdev
= rrdev
->bdev
;
806 BUG_ON(!(rw
& WRITE
));
807 rbi
->bi_end_io
= raid5_end_write_request
;
808 rbi
->bi_private
= sh
;
810 pr_debug("%s: for %llu schedule op %ld on "
811 "replacement disc %d\n",
812 __func__
, (unsigned long long)sh
->sector
,
814 atomic_inc(&sh
->count
);
815 if (use_new_offset(conf
, sh
))
816 rbi
->bi_sector
= (sh
->sector
817 + rrdev
->new_data_offset
);
819 rbi
->bi_sector
= (sh
->sector
820 + rrdev
->data_offset
);
822 rbi
->bi_io_vec
[0].bv_len
= STRIPE_SIZE
;
823 rbi
->bi_io_vec
[0].bv_offset
= 0;
824 rbi
->bi_size
= STRIPE_SIZE
;
826 * If this is discard request, set bi_vcnt 0. We don't
827 * want to confuse SCSI because SCSI will replace payload
829 if (rw
& REQ_DISCARD
)
831 if (conf
->mddev
->gendisk
)
832 trace_block_bio_remap(bdev_get_queue(rbi
->bi_bdev
),
833 rbi
, disk_devt(conf
->mddev
->gendisk
),
835 generic_make_request(rbi
);
837 if (!rdev
&& !rrdev
) {
839 set_bit(STRIPE_DEGRADED
, &sh
->state
);
840 pr_debug("skip op %ld on disc %d for sector %llu\n",
841 bi
->bi_rw
, i
, (unsigned long long)sh
->sector
);
842 clear_bit(R5_LOCKED
, &sh
->dev
[i
].flags
);
843 set_bit(STRIPE_HANDLE
, &sh
->state
);
848 static struct dma_async_tx_descriptor
*
849 async_copy_data(int frombio
, struct bio
*bio
, struct page
*page
,
850 sector_t sector
, struct dma_async_tx_descriptor
*tx
)
853 struct page
*bio_page
;
856 struct async_submit_ctl submit
;
857 enum async_tx_flags flags
= 0;
859 if (bio
->bi_sector
>= sector
)
860 page_offset
= (signed)(bio
->bi_sector
- sector
) * 512;
862 page_offset
= (signed)(sector
- bio
->bi_sector
) * -512;
865 flags
|= ASYNC_TX_FENCE
;
866 init_async_submit(&submit
, flags
, tx
, NULL
, NULL
, NULL
);
868 bio_for_each_segment(bvl
, bio
, i
) {
869 int len
= bvl
->bv_len
;
873 if (page_offset
< 0) {
874 b_offset
= -page_offset
;
875 page_offset
+= b_offset
;
879 if (len
> 0 && page_offset
+ len
> STRIPE_SIZE
)
880 clen
= STRIPE_SIZE
- page_offset
;
885 b_offset
+= bvl
->bv_offset
;
886 bio_page
= bvl
->bv_page
;
888 tx
= async_memcpy(page
, bio_page
, page_offset
,
889 b_offset
, clen
, &submit
);
891 tx
= async_memcpy(bio_page
, page
, b_offset
,
892 page_offset
, clen
, &submit
);
894 /* chain the operations */
895 submit
.depend_tx
= tx
;
897 if (clen
< len
) /* hit end of page */
905 static void ops_complete_biofill(void *stripe_head_ref
)
907 struct stripe_head
*sh
= stripe_head_ref
;
908 struct bio
*return_bi
= NULL
;
911 pr_debug("%s: stripe %llu\n", __func__
,
912 (unsigned long long)sh
->sector
);
914 /* clear completed biofills */
915 for (i
= sh
->disks
; i
--; ) {
916 struct r5dev
*dev
= &sh
->dev
[i
];
918 /* acknowledge completion of a biofill operation */
919 /* and check if we need to reply to a read request,
920 * new R5_Wantfill requests are held off until
921 * !STRIPE_BIOFILL_RUN
923 if (test_and_clear_bit(R5_Wantfill
, &dev
->flags
)) {
924 struct bio
*rbi
, *rbi2
;
929 while (rbi
&& rbi
->bi_sector
<
930 dev
->sector
+ STRIPE_SECTORS
) {
931 rbi2
= r5_next_bio(rbi
, dev
->sector
);
932 if (!raid5_dec_bi_active_stripes(rbi
)) {
933 rbi
->bi_next
= return_bi
;
940 clear_bit(STRIPE_BIOFILL_RUN
, &sh
->state
);
942 return_io(return_bi
);
944 set_bit(STRIPE_HANDLE
, &sh
->state
);
948 static void ops_run_biofill(struct stripe_head
*sh
)
950 struct dma_async_tx_descriptor
*tx
= NULL
;
951 struct async_submit_ctl submit
;
954 pr_debug("%s: stripe %llu\n", __func__
,
955 (unsigned long long)sh
->sector
);
957 for (i
= sh
->disks
; i
--; ) {
958 struct r5dev
*dev
= &sh
->dev
[i
];
959 if (test_bit(R5_Wantfill
, &dev
->flags
)) {
961 spin_lock_irq(&sh
->stripe_lock
);
962 dev
->read
= rbi
= dev
->toread
;
964 spin_unlock_irq(&sh
->stripe_lock
);
965 while (rbi
&& rbi
->bi_sector
<
966 dev
->sector
+ STRIPE_SECTORS
) {
967 tx
= async_copy_data(0, rbi
, dev
->page
,
969 rbi
= r5_next_bio(rbi
, dev
->sector
);
974 atomic_inc(&sh
->count
);
975 init_async_submit(&submit
, ASYNC_TX_ACK
, tx
, ops_complete_biofill
, sh
, NULL
);
976 async_trigger_callback(&submit
);
979 static void mark_target_uptodate(struct stripe_head
*sh
, int target
)
986 tgt
= &sh
->dev
[target
];
987 set_bit(R5_UPTODATE
, &tgt
->flags
);
988 BUG_ON(!test_bit(R5_Wantcompute
, &tgt
->flags
));
989 clear_bit(R5_Wantcompute
, &tgt
->flags
);
992 static void ops_complete_compute(void *stripe_head_ref
)
994 struct stripe_head
*sh
= stripe_head_ref
;
996 pr_debug("%s: stripe %llu\n", __func__
,
997 (unsigned long long)sh
->sector
);
999 /* mark the computed target(s) as uptodate */
1000 mark_target_uptodate(sh
, sh
->ops
.target
);
1001 mark_target_uptodate(sh
, sh
->ops
.target2
);
1003 clear_bit(STRIPE_COMPUTE_RUN
, &sh
->state
);
1004 if (sh
->check_state
== check_state_compute_run
)
1005 sh
->check_state
= check_state_compute_result
;
1006 set_bit(STRIPE_HANDLE
, &sh
->state
);
1010 /* return a pointer to the address conversion region of the scribble buffer */
1011 static addr_conv_t
*to_addr_conv(struct stripe_head
*sh
,
1012 struct raid5_percpu
*percpu
)
1014 return percpu
->scribble
+ sizeof(struct page
*) * (sh
->disks
+ 2);
1017 static struct dma_async_tx_descriptor
*
1018 ops_run_compute5(struct stripe_head
*sh
, struct raid5_percpu
*percpu
)
1020 int disks
= sh
->disks
;
1021 struct page
**xor_srcs
= percpu
->scribble
;
1022 int target
= sh
->ops
.target
;
1023 struct r5dev
*tgt
= &sh
->dev
[target
];
1024 struct page
*xor_dest
= tgt
->page
;
1026 struct dma_async_tx_descriptor
*tx
;
1027 struct async_submit_ctl submit
;
1030 pr_debug("%s: stripe %llu block: %d\n",
1031 __func__
, (unsigned long long)sh
->sector
, target
);
1032 BUG_ON(!test_bit(R5_Wantcompute
, &tgt
->flags
));
1034 for (i
= disks
; i
--; )
1036 xor_srcs
[count
++] = sh
->dev
[i
].page
;
1038 atomic_inc(&sh
->count
);
1040 init_async_submit(&submit
, ASYNC_TX_FENCE
|ASYNC_TX_XOR_ZERO_DST
, NULL
,
1041 ops_complete_compute
, sh
, to_addr_conv(sh
, percpu
));
1042 if (unlikely(count
== 1))
1043 tx
= async_memcpy(xor_dest
, xor_srcs
[0], 0, 0, STRIPE_SIZE
, &submit
);
1045 tx
= async_xor(xor_dest
, xor_srcs
, 0, count
, STRIPE_SIZE
, &submit
);
1050 /* set_syndrome_sources - populate source buffers for gen_syndrome
1051 * @srcs - (struct page *) array of size sh->disks
1052 * @sh - stripe_head to parse
1054 * Populates srcs in proper layout order for the stripe and returns the
1055 * 'count' of sources to be used in a call to async_gen_syndrome. The P
1056 * destination buffer is recorded in srcs[count] and the Q destination
1057 * is recorded in srcs[count+1]].
1059 static int set_syndrome_sources(struct page
**srcs
, struct stripe_head
*sh
)
1061 int disks
= sh
->disks
;
1062 int syndrome_disks
= sh
->ddf_layout
? disks
: (disks
- 2);
1063 int d0_idx
= raid6_d0(sh
);
1067 for (i
= 0; i
< disks
; i
++)
1073 int slot
= raid6_idx_to_slot(i
, sh
, &count
, syndrome_disks
);
1075 srcs
[slot
] = sh
->dev
[i
].page
;
1076 i
= raid6_next_disk(i
, disks
);
1077 } while (i
!= d0_idx
);
1079 return syndrome_disks
;
1082 static struct dma_async_tx_descriptor
*
1083 ops_run_compute6_1(struct stripe_head
*sh
, struct raid5_percpu
*percpu
)
1085 int disks
= sh
->disks
;
1086 struct page
**blocks
= percpu
->scribble
;
1088 int qd_idx
= sh
->qd_idx
;
1089 struct dma_async_tx_descriptor
*tx
;
1090 struct async_submit_ctl submit
;
1096 if (sh
->ops
.target
< 0)
1097 target
= sh
->ops
.target2
;
1098 else if (sh
->ops
.target2
< 0)
1099 target
= sh
->ops
.target
;
1101 /* we should only have one valid target */
1104 pr_debug("%s: stripe %llu block: %d\n",
1105 __func__
, (unsigned long long)sh
->sector
, target
);
1107 tgt
= &sh
->dev
[target
];
1108 BUG_ON(!test_bit(R5_Wantcompute
, &tgt
->flags
));
1111 atomic_inc(&sh
->count
);
1113 if (target
== qd_idx
) {
1114 count
= set_syndrome_sources(blocks
, sh
);
1115 blocks
[count
] = NULL
; /* regenerating p is not necessary */
1116 BUG_ON(blocks
[count
+1] != dest
); /* q should already be set */
1117 init_async_submit(&submit
, ASYNC_TX_FENCE
, NULL
,
1118 ops_complete_compute
, sh
,
1119 to_addr_conv(sh
, percpu
));
1120 tx
= async_gen_syndrome(blocks
, 0, count
+2, STRIPE_SIZE
, &submit
);
1122 /* Compute any data- or p-drive using XOR */
1124 for (i
= disks
; i
-- ; ) {
1125 if (i
== target
|| i
== qd_idx
)
1127 blocks
[count
++] = sh
->dev
[i
].page
;
1130 init_async_submit(&submit
, ASYNC_TX_FENCE
|ASYNC_TX_XOR_ZERO_DST
,
1131 NULL
, ops_complete_compute
, sh
,
1132 to_addr_conv(sh
, percpu
));
1133 tx
= async_xor(dest
, blocks
, 0, count
, STRIPE_SIZE
, &submit
);
1139 static struct dma_async_tx_descriptor
*
1140 ops_run_compute6_2(struct stripe_head
*sh
, struct raid5_percpu
*percpu
)
1142 int i
, count
, disks
= sh
->disks
;
1143 int syndrome_disks
= sh
->ddf_layout
? disks
: disks
-2;
1144 int d0_idx
= raid6_d0(sh
);
1145 int faila
= -1, failb
= -1;
1146 int target
= sh
->ops
.target
;
1147 int target2
= sh
->ops
.target2
;
1148 struct r5dev
*tgt
= &sh
->dev
[target
];
1149 struct r5dev
*tgt2
= &sh
->dev
[target2
];
1150 struct dma_async_tx_descriptor
*tx
;
1151 struct page
**blocks
= percpu
->scribble
;
1152 struct async_submit_ctl submit
;
1154 pr_debug("%s: stripe %llu block1: %d block2: %d\n",
1155 __func__
, (unsigned long long)sh
->sector
, target
, target2
);
1156 BUG_ON(target
< 0 || target2
< 0);
1157 BUG_ON(!test_bit(R5_Wantcompute
, &tgt
->flags
));
1158 BUG_ON(!test_bit(R5_Wantcompute
, &tgt2
->flags
));
1160 /* we need to open-code set_syndrome_sources to handle the
1161 * slot number conversion for 'faila' and 'failb'
1163 for (i
= 0; i
< disks
; i
++)
1168 int slot
= raid6_idx_to_slot(i
, sh
, &count
, syndrome_disks
);
1170 blocks
[slot
] = sh
->dev
[i
].page
;
1176 i
= raid6_next_disk(i
, disks
);
1177 } while (i
!= d0_idx
);
1179 BUG_ON(faila
== failb
);
1182 pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
1183 __func__
, (unsigned long long)sh
->sector
, faila
, failb
);
1185 atomic_inc(&sh
->count
);
1187 if (failb
== syndrome_disks
+1) {
1188 /* Q disk is one of the missing disks */
1189 if (faila
== syndrome_disks
) {
1190 /* Missing P+Q, just recompute */
1191 init_async_submit(&submit
, ASYNC_TX_FENCE
, NULL
,
1192 ops_complete_compute
, sh
,
1193 to_addr_conv(sh
, percpu
));
1194 return async_gen_syndrome(blocks
, 0, syndrome_disks
+2,
1195 STRIPE_SIZE
, &submit
);
1199 int qd_idx
= sh
->qd_idx
;
1201 /* Missing D+Q: recompute D from P, then recompute Q */
1202 if (target
== qd_idx
)
1203 data_target
= target2
;
1205 data_target
= target
;
1208 for (i
= disks
; i
-- ; ) {
1209 if (i
== data_target
|| i
== qd_idx
)
1211 blocks
[count
++] = sh
->dev
[i
].page
;
1213 dest
= sh
->dev
[data_target
].page
;
1214 init_async_submit(&submit
,
1215 ASYNC_TX_FENCE
|ASYNC_TX_XOR_ZERO_DST
,
1217 to_addr_conv(sh
, percpu
));
1218 tx
= async_xor(dest
, blocks
, 0, count
, STRIPE_SIZE
,
1221 count
= set_syndrome_sources(blocks
, sh
);
1222 init_async_submit(&submit
, ASYNC_TX_FENCE
, tx
,
1223 ops_complete_compute
, sh
,
1224 to_addr_conv(sh
, percpu
));
1225 return async_gen_syndrome(blocks
, 0, count
+2,
1226 STRIPE_SIZE
, &submit
);
1229 init_async_submit(&submit
, ASYNC_TX_FENCE
, NULL
,
1230 ops_complete_compute
, sh
,
1231 to_addr_conv(sh
, percpu
));
1232 if (failb
== syndrome_disks
) {
1233 /* We're missing D+P. */
1234 return async_raid6_datap_recov(syndrome_disks
+2,
1238 /* We're missing D+D. */
1239 return async_raid6_2data_recov(syndrome_disks
+2,
1240 STRIPE_SIZE
, faila
, failb
,
1247 static void ops_complete_prexor(void *stripe_head_ref
)
1249 struct stripe_head
*sh
= stripe_head_ref
;
1251 pr_debug("%s: stripe %llu\n", __func__
,
1252 (unsigned long long)sh
->sector
);
1255 static struct dma_async_tx_descriptor
*
1256 ops_run_prexor(struct stripe_head
*sh
, struct raid5_percpu
*percpu
,
1257 struct dma_async_tx_descriptor
*tx
)
1259 int disks
= sh
->disks
;
1260 struct page
**xor_srcs
= percpu
->scribble
;
1261 int count
= 0, pd_idx
= sh
->pd_idx
, i
;
1262 struct async_submit_ctl submit
;
1264 /* existing parity data subtracted */
1265 struct page
*xor_dest
= xor_srcs
[count
++] = sh
->dev
[pd_idx
].page
;
1267 pr_debug("%s: stripe %llu\n", __func__
,
1268 (unsigned long long)sh
->sector
);
1270 for (i
= disks
; i
--; ) {
1271 struct r5dev
*dev
= &sh
->dev
[i
];
1272 /* Only process blocks that are known to be uptodate */
1273 if (test_bit(R5_Wantdrain
, &dev
->flags
))
1274 xor_srcs
[count
++] = dev
->page
;
1277 init_async_submit(&submit
, ASYNC_TX_FENCE
|ASYNC_TX_XOR_DROP_DST
, tx
,
1278 ops_complete_prexor
, sh
, to_addr_conv(sh
, percpu
));
1279 tx
= async_xor(xor_dest
, xor_srcs
, 0, count
, STRIPE_SIZE
, &submit
);
1284 static struct dma_async_tx_descriptor
*
1285 ops_run_biodrain(struct stripe_head
*sh
, struct dma_async_tx_descriptor
*tx
)
1287 int disks
= sh
->disks
;
1290 pr_debug("%s: stripe %llu\n", __func__
,
1291 (unsigned long long)sh
->sector
);
1293 for (i
= disks
; i
--; ) {
1294 struct r5dev
*dev
= &sh
->dev
[i
];
1297 if (test_and_clear_bit(R5_Wantdrain
, &dev
->flags
)) {
1300 spin_lock_irq(&sh
->stripe_lock
);
1301 chosen
= dev
->towrite
;
1302 dev
->towrite
= NULL
;
1303 BUG_ON(dev
->written
);
1304 wbi
= dev
->written
= chosen
;
1305 spin_unlock_irq(&sh
->stripe_lock
);
1307 while (wbi
&& wbi
->bi_sector
<
1308 dev
->sector
+ STRIPE_SECTORS
) {
1309 if (wbi
->bi_rw
& REQ_FUA
)
1310 set_bit(R5_WantFUA
, &dev
->flags
);
1311 if (wbi
->bi_rw
& REQ_SYNC
)
1312 set_bit(R5_SyncIO
, &dev
->flags
);
1313 if (wbi
->bi_rw
& REQ_DISCARD
)
1314 set_bit(R5_Discard
, &dev
->flags
);
1316 tx
= async_copy_data(1, wbi
, dev
->page
,
1318 wbi
= r5_next_bio(wbi
, dev
->sector
);
1326 static void ops_complete_reconstruct(void *stripe_head_ref
)
1328 struct stripe_head
*sh
= stripe_head_ref
;
1329 int disks
= sh
->disks
;
1330 int pd_idx
= sh
->pd_idx
;
1331 int qd_idx
= sh
->qd_idx
;
1333 bool fua
= false, sync
= false, discard
= false;
1335 pr_debug("%s: stripe %llu\n", __func__
,
1336 (unsigned long long)sh
->sector
);
1338 for (i
= disks
; i
--; ) {
1339 fua
|= test_bit(R5_WantFUA
, &sh
->dev
[i
].flags
);
1340 sync
|= test_bit(R5_SyncIO
, &sh
->dev
[i
].flags
);
1341 discard
|= test_bit(R5_Discard
, &sh
->dev
[i
].flags
);
1344 for (i
= disks
; i
--; ) {
1345 struct r5dev
*dev
= &sh
->dev
[i
];
1347 if (dev
->written
|| i
== pd_idx
|| i
== qd_idx
) {
1349 set_bit(R5_UPTODATE
, &dev
->flags
);
1351 set_bit(R5_WantFUA
, &dev
->flags
);
1353 set_bit(R5_SyncIO
, &dev
->flags
);
1357 if (sh
->reconstruct_state
== reconstruct_state_drain_run
)
1358 sh
->reconstruct_state
= reconstruct_state_drain_result
;
1359 else if (sh
->reconstruct_state
== reconstruct_state_prexor_drain_run
)
1360 sh
->reconstruct_state
= reconstruct_state_prexor_drain_result
;
1362 BUG_ON(sh
->reconstruct_state
!= reconstruct_state_run
);
1363 sh
->reconstruct_state
= reconstruct_state_result
;
1366 set_bit(STRIPE_HANDLE
, &sh
->state
);
1371 ops_run_reconstruct5(struct stripe_head
*sh
, struct raid5_percpu
*percpu
,
1372 struct dma_async_tx_descriptor
*tx
)
1374 int disks
= sh
->disks
;
1375 struct page
**xor_srcs
= percpu
->scribble
;
1376 struct async_submit_ctl submit
;
1377 int count
= 0, pd_idx
= sh
->pd_idx
, i
;
1378 struct page
*xor_dest
;
1380 unsigned long flags
;
1382 pr_debug("%s: stripe %llu\n", __func__
,
1383 (unsigned long long)sh
->sector
);
1385 for (i
= 0; i
< sh
->disks
; i
++) {
1388 if (!test_bit(R5_Discard
, &sh
->dev
[i
].flags
))
1391 if (i
>= sh
->disks
) {
1392 atomic_inc(&sh
->count
);
1393 set_bit(R5_Discard
, &sh
->dev
[pd_idx
].flags
);
1394 ops_complete_reconstruct(sh
);
1397 /* check if prexor is active which means only process blocks
1398 * that are part of a read-modify-write (written)
1400 if (sh
->reconstruct_state
== reconstruct_state_prexor_drain_run
) {
1402 xor_dest
= xor_srcs
[count
++] = sh
->dev
[pd_idx
].page
;
1403 for (i
= disks
; i
--; ) {
1404 struct r5dev
*dev
= &sh
->dev
[i
];
1406 xor_srcs
[count
++] = dev
->page
;
1409 xor_dest
= sh
->dev
[pd_idx
].page
;
1410 for (i
= disks
; i
--; ) {
1411 struct r5dev
*dev
= &sh
->dev
[i
];
1413 xor_srcs
[count
++] = dev
->page
;
1417 /* 1/ if we prexor'd then the dest is reused as a source
1418 * 2/ if we did not prexor then we are redoing the parity
1419 * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
1420 * for the synchronous xor case
1422 flags
= ASYNC_TX_ACK
|
1423 (prexor
? ASYNC_TX_XOR_DROP_DST
: ASYNC_TX_XOR_ZERO_DST
);
1425 atomic_inc(&sh
->count
);
1427 init_async_submit(&submit
, flags
, tx
, ops_complete_reconstruct
, sh
,
1428 to_addr_conv(sh
, percpu
));
1429 if (unlikely(count
== 1))
1430 tx
= async_memcpy(xor_dest
, xor_srcs
[0], 0, 0, STRIPE_SIZE
, &submit
);
1432 tx
= async_xor(xor_dest
, xor_srcs
, 0, count
, STRIPE_SIZE
, &submit
);
1436 ops_run_reconstruct6(struct stripe_head
*sh
, struct raid5_percpu
*percpu
,
1437 struct dma_async_tx_descriptor
*tx
)
1439 struct async_submit_ctl submit
;
1440 struct page
**blocks
= percpu
->scribble
;
1443 pr_debug("%s: stripe %llu\n", __func__
, (unsigned long long)sh
->sector
);
1445 for (i
= 0; i
< sh
->disks
; i
++) {
1446 if (sh
->pd_idx
== i
|| sh
->qd_idx
== i
)
1448 if (!test_bit(R5_Discard
, &sh
->dev
[i
].flags
))
1451 if (i
>= sh
->disks
) {
1452 atomic_inc(&sh
->count
);
1453 set_bit(R5_Discard
, &sh
->dev
[sh
->pd_idx
].flags
);
1454 set_bit(R5_Discard
, &sh
->dev
[sh
->qd_idx
].flags
);
1455 ops_complete_reconstruct(sh
);
1459 count
= set_syndrome_sources(blocks
, sh
);
1461 atomic_inc(&sh
->count
);
1463 init_async_submit(&submit
, ASYNC_TX_ACK
, tx
, ops_complete_reconstruct
,
1464 sh
, to_addr_conv(sh
, percpu
));
1465 async_gen_syndrome(blocks
, 0, count
+2, STRIPE_SIZE
, &submit
);
1468 static void ops_complete_check(void *stripe_head_ref
)
1470 struct stripe_head
*sh
= stripe_head_ref
;
1472 pr_debug("%s: stripe %llu\n", __func__
,
1473 (unsigned long long)sh
->sector
);
1475 sh
->check_state
= check_state_check_result
;
1476 set_bit(STRIPE_HANDLE
, &sh
->state
);
1480 static void ops_run_check_p(struct stripe_head
*sh
, struct raid5_percpu
*percpu
)
1482 int disks
= sh
->disks
;
1483 int pd_idx
= sh
->pd_idx
;
1484 int qd_idx
= sh
->qd_idx
;
1485 struct page
*xor_dest
;
1486 struct page
**xor_srcs
= percpu
->scribble
;
1487 struct dma_async_tx_descriptor
*tx
;
1488 struct async_submit_ctl submit
;
1492 pr_debug("%s: stripe %llu\n", __func__
,
1493 (unsigned long long)sh
->sector
);
1496 xor_dest
= sh
->dev
[pd_idx
].page
;
1497 xor_srcs
[count
++] = xor_dest
;
1498 for (i
= disks
; i
--; ) {
1499 if (i
== pd_idx
|| i
== qd_idx
)
1501 xor_srcs
[count
++] = sh
->dev
[i
].page
;
1504 init_async_submit(&submit
, 0, NULL
, NULL
, NULL
,
1505 to_addr_conv(sh
, percpu
));
1506 tx
= async_xor_val(xor_dest
, xor_srcs
, 0, count
, STRIPE_SIZE
,
1507 &sh
->ops
.zero_sum_result
, &submit
);
1509 atomic_inc(&sh
->count
);
1510 init_async_submit(&submit
, ASYNC_TX_ACK
, tx
, ops_complete_check
, sh
, NULL
);
1511 tx
= async_trigger_callback(&submit
);
1514 static void ops_run_check_pq(struct stripe_head
*sh
, struct raid5_percpu
*percpu
, int checkp
)
1516 struct page
**srcs
= percpu
->scribble
;
1517 struct async_submit_ctl submit
;
1520 pr_debug("%s: stripe %llu checkp: %d\n", __func__
,
1521 (unsigned long long)sh
->sector
, checkp
);
1523 count
= set_syndrome_sources(srcs
, sh
);
1527 atomic_inc(&sh
->count
);
1528 init_async_submit(&submit
, ASYNC_TX_ACK
, NULL
, ops_complete_check
,
1529 sh
, to_addr_conv(sh
, percpu
));
1530 async_syndrome_val(srcs
, 0, count
+2, STRIPE_SIZE
,
1531 &sh
->ops
.zero_sum_result
, percpu
->spare_page
, &submit
);
1534 static void raid_run_ops(struct stripe_head
*sh
, unsigned long ops_request
)
1536 int overlap_clear
= 0, i
, disks
= sh
->disks
;
1537 struct dma_async_tx_descriptor
*tx
= NULL
;
1538 struct r5conf
*conf
= sh
->raid_conf
;
1539 int level
= conf
->level
;
1540 struct raid5_percpu
*percpu
;
1544 percpu
= per_cpu_ptr(conf
->percpu
, cpu
);
1545 if (test_bit(STRIPE_OP_BIOFILL
, &ops_request
)) {
1546 ops_run_biofill(sh
);
1550 if (test_bit(STRIPE_OP_COMPUTE_BLK
, &ops_request
)) {
1552 tx
= ops_run_compute5(sh
, percpu
);
1554 if (sh
->ops
.target2
< 0 || sh
->ops
.target
< 0)
1555 tx
= ops_run_compute6_1(sh
, percpu
);
1557 tx
= ops_run_compute6_2(sh
, percpu
);
1559 /* terminate the chain if reconstruct is not set to be run */
1560 if (tx
&& !test_bit(STRIPE_OP_RECONSTRUCT
, &ops_request
))
1564 if (test_bit(STRIPE_OP_PREXOR
, &ops_request
))
1565 tx
= ops_run_prexor(sh
, percpu
, tx
);
1567 if (test_bit(STRIPE_OP_BIODRAIN
, &ops_request
)) {
1568 tx
= ops_run_biodrain(sh
, tx
);
1572 if (test_bit(STRIPE_OP_RECONSTRUCT
, &ops_request
)) {
1574 ops_run_reconstruct5(sh
, percpu
, tx
);
1576 ops_run_reconstruct6(sh
, percpu
, tx
);
1579 if (test_bit(STRIPE_OP_CHECK
, &ops_request
)) {
1580 if (sh
->check_state
== check_state_run
)
1581 ops_run_check_p(sh
, percpu
);
1582 else if (sh
->check_state
== check_state_run_q
)
1583 ops_run_check_pq(sh
, percpu
, 0);
1584 else if (sh
->check_state
== check_state_run_pq
)
1585 ops_run_check_pq(sh
, percpu
, 1);
1591 for (i
= disks
; i
--; ) {
1592 struct r5dev
*dev
= &sh
->dev
[i
];
1593 if (test_and_clear_bit(R5_Overlap
, &dev
->flags
))
1594 wake_up(&sh
->raid_conf
->wait_for_overlap
);
1599 static int grow_one_stripe(struct r5conf
*conf
)
1601 struct stripe_head
*sh
;
1602 sh
= kmem_cache_zalloc(conf
->slab_cache
, GFP_KERNEL
);
1606 sh
->raid_conf
= conf
;
1608 spin_lock_init(&sh
->stripe_lock
);
1610 if (grow_buffers(sh
)) {
1612 kmem_cache_free(conf
->slab_cache
, sh
);
1615 /* we just created an active stripe so... */
1616 atomic_set(&sh
->count
, 1);
1617 atomic_inc(&conf
->active_stripes
);
1618 INIT_LIST_HEAD(&sh
->lru
);
1623 static int grow_stripes(struct r5conf
*conf
, int num
)
1625 struct kmem_cache
*sc
;
1626 int devs
= max(conf
->raid_disks
, conf
->previous_raid_disks
);
1628 if (conf
->mddev
->gendisk
)
1629 sprintf(conf
->cache_name
[0],
1630 "raid%d-%s", conf
->level
, mdname(conf
->mddev
));
1632 sprintf(conf
->cache_name
[0],
1633 "raid%d-%p", conf
->level
, conf
->mddev
);
1634 sprintf(conf
->cache_name
[1], "%s-alt", conf
->cache_name
[0]);
1636 conf
->active_name
= 0;
1637 sc
= kmem_cache_create(conf
->cache_name
[conf
->active_name
],
1638 sizeof(struct stripe_head
)+(devs
-1)*sizeof(struct r5dev
),
1642 conf
->slab_cache
= sc
;
1643 conf
->pool_size
= devs
;
1645 if (!grow_one_stripe(conf
))
1651 * scribble_len - return the required size of the scribble region
1652 * @num - total number of disks in the array
1654 * The size must be enough to contain:
1655 * 1/ a struct page pointer for each device in the array +2
1656 * 2/ room to convert each entry in (1) to its corresponding dma
1657 * (dma_map_page()) or page (page_address()) address.
1659 * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
1660 * calculate over all devices (not just the data blocks), using zeros in place
1661 * of the P and Q blocks.
1663 static size_t scribble_len(int num
)
1667 len
= sizeof(struct page
*) * (num
+2) + sizeof(addr_conv_t
) * (num
+2);
1672 static int resize_stripes(struct r5conf
*conf
, int newsize
)
1674 /* Make all the stripes able to hold 'newsize' devices.
1675 * New slots in each stripe get 'page' set to a new page.
1677 * This happens in stages:
1678 * 1/ create a new kmem_cache and allocate the required number of
1680 * 2/ gather all the old stripe_heads and transfer the pages across
1681 * to the new stripe_heads. This will have the side effect of
1682 * freezing the array as once all stripe_heads have been collected,
1683 * no IO will be possible. Old stripe heads are freed once their
1684 * pages have been transferred over, and the old kmem_cache is
1685 * freed when all stripes are done.
1686 * 3/ reallocate conf->disks to be suitable bigger. If this fails,
1687 * we simple return a failre status - no need to clean anything up.
1688 * 4/ allocate new pages for the new slots in the new stripe_heads.
1689 * If this fails, we don't bother trying the shrink the
1690 * stripe_heads down again, we just leave them as they are.
1691 * As each stripe_head is processed the new one is released into
1694 * Once step2 is started, we cannot afford to wait for a write,
1695 * so we use GFP_NOIO allocations.
1697 struct stripe_head
*osh
, *nsh
;
1698 LIST_HEAD(newstripes
);
1699 struct disk_info
*ndisks
;
1702 struct kmem_cache
*sc
;
1705 if (newsize
<= conf
->pool_size
)
1706 return 0; /* never bother to shrink */
1708 err
= md_allow_write(conf
->mddev
);
1713 sc
= kmem_cache_create(conf
->cache_name
[1-conf
->active_name
],
1714 sizeof(struct stripe_head
)+(newsize
-1)*sizeof(struct r5dev
),
1719 for (i
= conf
->max_nr_stripes
; i
; i
--) {
1720 nsh
= kmem_cache_zalloc(sc
, GFP_KERNEL
);
1724 nsh
->raid_conf
= conf
;
1725 spin_lock_init(&nsh
->stripe_lock
);
1727 list_add(&nsh
->lru
, &newstripes
);
1730 /* didn't get enough, give up */
1731 while (!list_empty(&newstripes
)) {
1732 nsh
= list_entry(newstripes
.next
, struct stripe_head
, lru
);
1733 list_del(&nsh
->lru
);
1734 kmem_cache_free(sc
, nsh
);
1736 kmem_cache_destroy(sc
);
1739 /* Step 2 - Must use GFP_NOIO now.
1740 * OK, we have enough stripes, start collecting inactive
1741 * stripes and copying them over
1743 list_for_each_entry(nsh
, &newstripes
, lru
) {
1744 spin_lock_irq(&conf
->device_lock
);
1745 wait_event_lock_irq(conf
->wait_for_stripe
,
1746 !list_empty(&conf
->inactive_list
),
1748 osh
= get_free_stripe(conf
);
1749 spin_unlock_irq(&conf
->device_lock
);
1750 atomic_set(&nsh
->count
, 1);
1751 for(i
=0; i
<conf
->pool_size
; i
++)
1752 nsh
->dev
[i
].page
= osh
->dev
[i
].page
;
1753 for( ; i
<newsize
; i
++)
1754 nsh
->dev
[i
].page
= NULL
;
1755 kmem_cache_free(conf
->slab_cache
, osh
);
1757 kmem_cache_destroy(conf
->slab_cache
);
1760 * At this point, we are holding all the stripes so the array
1761 * is completely stalled, so now is a good time to resize
1762 * conf->disks and the scribble region
1764 ndisks
= kzalloc(newsize
* sizeof(struct disk_info
), GFP_NOIO
);
1766 for (i
=0; i
<conf
->raid_disks
; i
++)
1767 ndisks
[i
] = conf
->disks
[i
];
1769 conf
->disks
= ndisks
;
1774 conf
->scribble_len
= scribble_len(newsize
);
1775 for_each_present_cpu(cpu
) {
1776 struct raid5_percpu
*percpu
;
1779 percpu
= per_cpu_ptr(conf
->percpu
, cpu
);
1780 scribble
= kmalloc(conf
->scribble_len
, GFP_NOIO
);
1783 kfree(percpu
->scribble
);
1784 percpu
->scribble
= scribble
;
1792 /* Step 4, return new stripes to service */
1793 while(!list_empty(&newstripes
)) {
1794 nsh
= list_entry(newstripes
.next
, struct stripe_head
, lru
);
1795 list_del_init(&nsh
->lru
);
1797 for (i
=conf
->raid_disks
; i
< newsize
; i
++)
1798 if (nsh
->dev
[i
].page
== NULL
) {
1799 struct page
*p
= alloc_page(GFP_NOIO
);
1800 nsh
->dev
[i
].page
= p
;
1804 release_stripe(nsh
);
1806 /* critical section pass, GFP_NOIO no longer needed */
1808 conf
->slab_cache
= sc
;
1809 conf
->active_name
= 1-conf
->active_name
;
1810 conf
->pool_size
= newsize
;
1814 static int drop_one_stripe(struct r5conf
*conf
)
1816 struct stripe_head
*sh
;
1818 spin_lock_irq(&conf
->device_lock
);
1819 sh
= get_free_stripe(conf
);
1820 spin_unlock_irq(&conf
->device_lock
);
1823 BUG_ON(atomic_read(&sh
->count
));
1825 kmem_cache_free(conf
->slab_cache
, sh
);
1826 atomic_dec(&conf
->active_stripes
);
1830 static void shrink_stripes(struct r5conf
*conf
)
1832 while (drop_one_stripe(conf
))
1835 if (conf
->slab_cache
)
1836 kmem_cache_destroy(conf
->slab_cache
);
1837 conf
->slab_cache
= NULL
;
1840 static void raid5_end_read_request(struct bio
* bi
, int error
)
1842 struct stripe_head
*sh
= bi
->bi_private
;
1843 struct r5conf
*conf
= sh
->raid_conf
;
1844 int disks
= sh
->disks
, i
;
1845 int uptodate
= test_bit(BIO_UPTODATE
, &bi
->bi_flags
);
1846 char b
[BDEVNAME_SIZE
];
1847 struct md_rdev
*rdev
= NULL
;
1850 for (i
=0 ; i
<disks
; i
++)
1851 if (bi
== &sh
->dev
[i
].req
)
1854 pr_debug("end_read_request %llu/%d, count: %d, uptodate %d.\n",
1855 (unsigned long long)sh
->sector
, i
, atomic_read(&sh
->count
),
1861 if (test_bit(R5_ReadRepl
, &sh
->dev
[i
].flags
))
1862 /* If replacement finished while this request was outstanding,
1863 * 'replacement' might be NULL already.
1864 * In that case it moved down to 'rdev'.
1865 * rdev is not removed until all requests are finished.
1867 rdev
= conf
->disks
[i
].replacement
;
1869 rdev
= conf
->disks
[i
].rdev
;
1871 if (use_new_offset(conf
, sh
))
1872 s
= sh
->sector
+ rdev
->new_data_offset
;
1874 s
= sh
->sector
+ rdev
->data_offset
;
1876 set_bit(R5_UPTODATE
, &sh
->dev
[i
].flags
);
1877 if (test_bit(R5_ReadError
, &sh
->dev
[i
].flags
)) {
1878 /* Note that this cannot happen on a
1879 * replacement device. We just fail those on
1884 "md/raid:%s: read error corrected"
1885 " (%lu sectors at %llu on %s)\n",
1886 mdname(conf
->mddev
), STRIPE_SECTORS
,
1887 (unsigned long long)s
,
1888 bdevname(rdev
->bdev
, b
));
1889 atomic_add(STRIPE_SECTORS
, &rdev
->corrected_errors
);
1890 clear_bit(R5_ReadError
, &sh
->dev
[i
].flags
);
1891 clear_bit(R5_ReWrite
, &sh
->dev
[i
].flags
);
1892 } else if (test_bit(R5_ReadNoMerge
, &sh
->dev
[i
].flags
))
1893 clear_bit(R5_ReadNoMerge
, &sh
->dev
[i
].flags
);
1895 if (atomic_read(&rdev
->read_errors
))
1896 atomic_set(&rdev
->read_errors
, 0);
1898 const char *bdn
= bdevname(rdev
->bdev
, b
);
1902 clear_bit(R5_UPTODATE
, &sh
->dev
[i
].flags
);
1903 atomic_inc(&rdev
->read_errors
);
1904 if (test_bit(R5_ReadRepl
, &sh
->dev
[i
].flags
))
1907 "md/raid:%s: read error on replacement device "
1908 "(sector %llu on %s).\n",
1909 mdname(conf
->mddev
),
1910 (unsigned long long)s
,
1912 else if (conf
->mddev
->degraded
>= conf
->max_degraded
) {
1916 "md/raid:%s: read error not correctable "
1917 "(sector %llu on %s).\n",
1918 mdname(conf
->mddev
),
1919 (unsigned long long)s
,
1921 } else if (test_bit(R5_ReWrite
, &sh
->dev
[i
].flags
)) {
1926 "md/raid:%s: read error NOT corrected!! "
1927 "(sector %llu on %s).\n",
1928 mdname(conf
->mddev
),
1929 (unsigned long long)s
,
1931 } else if (atomic_read(&rdev
->read_errors
)
1932 > conf
->max_nr_stripes
)
1934 "md/raid:%s: Too many read errors, failing device %s.\n",
1935 mdname(conf
->mddev
), bdn
);
1939 if (test_bit(R5_ReadNoMerge
, &sh
->dev
[i
].flags
)) {
1940 set_bit(R5_ReadError
, &sh
->dev
[i
].flags
);
1941 clear_bit(R5_ReadNoMerge
, &sh
->dev
[i
].flags
);
1943 set_bit(R5_ReadNoMerge
, &sh
->dev
[i
].flags
);
1945 clear_bit(R5_ReadError
, &sh
->dev
[i
].flags
);
1946 clear_bit(R5_ReWrite
, &sh
->dev
[i
].flags
);
1948 && test_bit(In_sync
, &rdev
->flags
)
1949 && rdev_set_badblocks(
1950 rdev
, sh
->sector
, STRIPE_SECTORS
, 0)))
1951 md_error(conf
->mddev
, rdev
);
1954 rdev_dec_pending(rdev
, conf
->mddev
);
1955 clear_bit(R5_LOCKED
, &sh
->dev
[i
].flags
);
1956 set_bit(STRIPE_HANDLE
, &sh
->state
);
1960 static void raid5_end_write_request(struct bio
*bi
, int error
)
1962 struct stripe_head
*sh
= bi
->bi_private
;
1963 struct r5conf
*conf
= sh
->raid_conf
;
1964 int disks
= sh
->disks
, i
;
1965 struct md_rdev
*uninitialized_var(rdev
);
1966 int uptodate
= test_bit(BIO_UPTODATE
, &bi
->bi_flags
);
1969 int replacement
= 0;
1971 for (i
= 0 ; i
< disks
; i
++) {
1972 if (bi
== &sh
->dev
[i
].req
) {
1973 rdev
= conf
->disks
[i
].rdev
;
1976 if (bi
== &sh
->dev
[i
].rreq
) {
1977 rdev
= conf
->disks
[i
].replacement
;
1981 /* rdev was removed and 'replacement'
1982 * replaced it. rdev is not removed
1983 * until all requests are finished.
1985 rdev
= conf
->disks
[i
].rdev
;
1989 pr_debug("end_write_request %llu/%d, count %d, uptodate: %d.\n",
1990 (unsigned long long)sh
->sector
, i
, atomic_read(&sh
->count
),
1999 md_error(conf
->mddev
, rdev
);
2000 else if (is_badblock(rdev
, sh
->sector
,
2002 &first_bad
, &bad_sectors
))
2003 set_bit(R5_MadeGoodRepl
, &sh
->dev
[i
].flags
);
2006 set_bit(WriteErrorSeen
, &rdev
->flags
);
2007 set_bit(R5_WriteError
, &sh
->dev
[i
].flags
);
2008 if (!test_and_set_bit(WantReplacement
, &rdev
->flags
))
2009 set_bit(MD_RECOVERY_NEEDED
,
2010 &rdev
->mddev
->recovery
);
2011 } else if (is_badblock(rdev
, sh
->sector
,
2013 &first_bad
, &bad_sectors
)) {
2014 set_bit(R5_MadeGood
, &sh
->dev
[i
].flags
);
2015 if (test_bit(R5_ReadError
, &sh
->dev
[i
].flags
))
2016 /* That was a successful write so make
2017 * sure it looks like we already did
2020 set_bit(R5_ReWrite
, &sh
->dev
[i
].flags
);
2023 rdev_dec_pending(rdev
, conf
->mddev
);
2025 if (!test_and_clear_bit(R5_DOUBLE_LOCKED
, &sh
->dev
[i
].flags
))
2026 clear_bit(R5_LOCKED
, &sh
->dev
[i
].flags
);
2027 set_bit(STRIPE_HANDLE
, &sh
->state
);
2031 static sector_t
compute_blocknr(struct stripe_head
*sh
, int i
, int previous
);
2033 static void raid5_build_block(struct stripe_head
*sh
, int i
, int previous
)
2035 struct r5dev
*dev
= &sh
->dev
[i
];
2037 bio_init(&dev
->req
);
2038 dev
->req
.bi_io_vec
= &dev
->vec
;
2040 dev
->req
.bi_max_vecs
++;
2041 dev
->req
.bi_private
= sh
;
2042 dev
->vec
.bv_page
= dev
->page
;
2044 bio_init(&dev
->rreq
);
2045 dev
->rreq
.bi_io_vec
= &dev
->rvec
;
2046 dev
->rreq
.bi_vcnt
++;
2047 dev
->rreq
.bi_max_vecs
++;
2048 dev
->rreq
.bi_private
= sh
;
2049 dev
->rvec
.bv_page
= dev
->page
;
2052 dev
->sector
= compute_blocknr(sh
, i
, previous
);
2055 static void error(struct mddev
*mddev
, struct md_rdev
*rdev
)
2057 char b
[BDEVNAME_SIZE
];
2058 struct r5conf
*conf
= mddev
->private;
2059 unsigned long flags
;
2060 pr_debug("raid456: error called\n");
2062 spin_lock_irqsave(&conf
->device_lock
, flags
);
2063 clear_bit(In_sync
, &rdev
->flags
);
2064 mddev
->degraded
= calc_degraded(conf
);
2065 spin_unlock_irqrestore(&conf
->device_lock
, flags
);
2066 set_bit(MD_RECOVERY_INTR
, &mddev
->recovery
);
2068 set_bit(Blocked
, &rdev
->flags
);
2069 set_bit(Faulty
, &rdev
->flags
);
2070 set_bit(MD_CHANGE_DEVS
, &mddev
->flags
);
2072 "md/raid:%s: Disk failure on %s, disabling device.\n"
2073 "md/raid:%s: Operation continuing on %d devices.\n",
2075 bdevname(rdev
->bdev
, b
),
2077 conf
->raid_disks
- mddev
->degraded
);
2081 * Input: a 'big' sector number,
2082 * Output: index of the data and parity disk, and the sector # in them.
2084 static sector_t
raid5_compute_sector(struct r5conf
*conf
, sector_t r_sector
,
2085 int previous
, int *dd_idx
,
2086 struct stripe_head
*sh
)
2088 sector_t stripe
, stripe2
;
2089 sector_t chunk_number
;
2090 unsigned int chunk_offset
;
2093 sector_t new_sector
;
2094 int algorithm
= previous
? conf
->prev_algo
2096 int sectors_per_chunk
= previous
? conf
->prev_chunk_sectors
2097 : conf
->chunk_sectors
;
2098 int raid_disks
= previous
? conf
->previous_raid_disks
2100 int data_disks
= raid_disks
- conf
->max_degraded
;
2102 /* First compute the information on this sector */
2105 * Compute the chunk number and the sector offset inside the chunk
2107 chunk_offset
= sector_div(r_sector
, sectors_per_chunk
);
2108 chunk_number
= r_sector
;
2111 * Compute the stripe number
2113 stripe
= chunk_number
;
2114 *dd_idx
= sector_div(stripe
, data_disks
);
2117 * Select the parity disk based on the user selected algorithm.
2119 pd_idx
= qd_idx
= -1;
2120 switch(conf
->level
) {
2122 pd_idx
= data_disks
;
2125 switch (algorithm
) {
2126 case ALGORITHM_LEFT_ASYMMETRIC
:
2127 pd_idx
= data_disks
- sector_div(stripe2
, raid_disks
);
2128 if (*dd_idx
>= pd_idx
)
2131 case ALGORITHM_RIGHT_ASYMMETRIC
:
2132 pd_idx
= sector_div(stripe2
, raid_disks
);
2133 if (*dd_idx
>= pd_idx
)
2136 case ALGORITHM_LEFT_SYMMETRIC
:
2137 pd_idx
= data_disks
- sector_div(stripe2
, raid_disks
);
2138 *dd_idx
= (pd_idx
+ 1 + *dd_idx
) % raid_disks
;
2140 case ALGORITHM_RIGHT_SYMMETRIC
:
2141 pd_idx
= sector_div(stripe2
, raid_disks
);
2142 *dd_idx
= (pd_idx
+ 1 + *dd_idx
) % raid_disks
;
2144 case ALGORITHM_PARITY_0
:
2148 case ALGORITHM_PARITY_N
:
2149 pd_idx
= data_disks
;
2157 switch (algorithm
) {
2158 case ALGORITHM_LEFT_ASYMMETRIC
:
2159 pd_idx
= raid_disks
- 1 - sector_div(stripe2
, raid_disks
);
2160 qd_idx
= pd_idx
+ 1;
2161 if (pd_idx
== raid_disks
-1) {
2162 (*dd_idx
)++; /* Q D D D P */
2164 } else if (*dd_idx
>= pd_idx
)
2165 (*dd_idx
) += 2; /* D D P Q D */
2167 case ALGORITHM_RIGHT_ASYMMETRIC
:
2168 pd_idx
= sector_div(stripe2
, raid_disks
);
2169 qd_idx
= pd_idx
+ 1;
2170 if (pd_idx
== raid_disks
-1) {
2171 (*dd_idx
)++; /* Q D D D P */
2173 } else if (*dd_idx
>= pd_idx
)
2174 (*dd_idx
) += 2; /* D D P Q D */
2176 case ALGORITHM_LEFT_SYMMETRIC
:
2177 pd_idx
= raid_disks
- 1 - sector_div(stripe2
, raid_disks
);
2178 qd_idx
= (pd_idx
+ 1) % raid_disks
;
2179 *dd_idx
= (pd_idx
+ 2 + *dd_idx
) % raid_disks
;
2181 case ALGORITHM_RIGHT_SYMMETRIC
:
2182 pd_idx
= sector_div(stripe2
, raid_disks
);
2183 qd_idx
= (pd_idx
+ 1) % raid_disks
;
2184 *dd_idx
= (pd_idx
+ 2 + *dd_idx
) % raid_disks
;
2187 case ALGORITHM_PARITY_0
:
2192 case ALGORITHM_PARITY_N
:
2193 pd_idx
= data_disks
;
2194 qd_idx
= data_disks
+ 1;
2197 case ALGORITHM_ROTATING_ZERO_RESTART
:
2198 /* Exactly the same as RIGHT_ASYMMETRIC, but or
2199 * of blocks for computing Q is different.
2201 pd_idx
= sector_div(stripe2
, raid_disks
);
2202 qd_idx
= pd_idx
+ 1;
2203 if (pd_idx
== raid_disks
-1) {
2204 (*dd_idx
)++; /* Q D D D P */
2206 } else if (*dd_idx
>= pd_idx
)
2207 (*dd_idx
) += 2; /* D D P Q D */
2211 case ALGORITHM_ROTATING_N_RESTART
:
2212 /* Same a left_asymmetric, by first stripe is
2213 * D D D P Q rather than
2217 pd_idx
= raid_disks
- 1 - sector_div(stripe2
, raid_disks
);
2218 qd_idx
= pd_idx
+ 1;
2219 if (pd_idx
== raid_disks
-1) {
2220 (*dd_idx
)++; /* Q D D D P */
2222 } else if (*dd_idx
>= pd_idx
)
2223 (*dd_idx
) += 2; /* D D P Q D */
2227 case ALGORITHM_ROTATING_N_CONTINUE
:
2228 /* Same as left_symmetric but Q is before P */
2229 pd_idx
= raid_disks
- 1 - sector_div(stripe2
, raid_disks
);
2230 qd_idx
= (pd_idx
+ raid_disks
- 1) % raid_disks
;
2231 *dd_idx
= (pd_idx
+ 1 + *dd_idx
) % raid_disks
;
2235 case ALGORITHM_LEFT_ASYMMETRIC_6
:
2236 /* RAID5 left_asymmetric, with Q on last device */
2237 pd_idx
= data_disks
- sector_div(stripe2
, raid_disks
-1);
2238 if (*dd_idx
>= pd_idx
)
2240 qd_idx
= raid_disks
- 1;
2243 case ALGORITHM_RIGHT_ASYMMETRIC_6
:
2244 pd_idx
= sector_div(stripe2
, raid_disks
-1);
2245 if (*dd_idx
>= pd_idx
)
2247 qd_idx
= raid_disks
- 1;
2250 case ALGORITHM_LEFT_SYMMETRIC_6
:
2251 pd_idx
= data_disks
- sector_div(stripe2
, raid_disks
-1);
2252 *dd_idx
= (pd_idx
+ 1 + *dd_idx
) % (raid_disks
-1);
2253 qd_idx
= raid_disks
- 1;
2256 case ALGORITHM_RIGHT_SYMMETRIC_6
:
2257 pd_idx
= sector_div(stripe2
, raid_disks
-1);
2258 *dd_idx
= (pd_idx
+ 1 + *dd_idx
) % (raid_disks
-1);
2259 qd_idx
= raid_disks
- 1;
2262 case ALGORITHM_PARITY_0_6
:
2265 qd_idx
= raid_disks
- 1;
2275 sh
->pd_idx
= pd_idx
;
2276 sh
->qd_idx
= qd_idx
;
2277 sh
->ddf_layout
= ddf_layout
;
2280 * Finally, compute the new sector number
2282 new_sector
= (sector_t
)stripe
* sectors_per_chunk
+ chunk_offset
;
2287 static sector_t
compute_blocknr(struct stripe_head
*sh
, int i
, int previous
)
2289 struct r5conf
*conf
= sh
->raid_conf
;
2290 int raid_disks
= sh
->disks
;
2291 int data_disks
= raid_disks
- conf
->max_degraded
;
2292 sector_t new_sector
= sh
->sector
, check
;
2293 int sectors_per_chunk
= previous
? conf
->prev_chunk_sectors
2294 : conf
->chunk_sectors
;
2295 int algorithm
= previous
? conf
->prev_algo
2299 sector_t chunk_number
;
2300 int dummy1
, dd_idx
= i
;
2302 struct stripe_head sh2
;
2305 chunk_offset
= sector_div(new_sector
, sectors_per_chunk
);
2306 stripe
= new_sector
;
2308 if (i
== sh
->pd_idx
)
2310 switch(conf
->level
) {
2313 switch (algorithm
) {
2314 case ALGORITHM_LEFT_ASYMMETRIC
:
2315 case ALGORITHM_RIGHT_ASYMMETRIC
:
2319 case ALGORITHM_LEFT_SYMMETRIC
:
2320 case ALGORITHM_RIGHT_SYMMETRIC
:
2323 i
-= (sh
->pd_idx
+ 1);
2325 case ALGORITHM_PARITY_0
:
2328 case ALGORITHM_PARITY_N
:
2335 if (i
== sh
->qd_idx
)
2336 return 0; /* It is the Q disk */
2337 switch (algorithm
) {
2338 case ALGORITHM_LEFT_ASYMMETRIC
:
2339 case ALGORITHM_RIGHT_ASYMMETRIC
:
2340 case ALGORITHM_ROTATING_ZERO_RESTART
:
2341 case ALGORITHM_ROTATING_N_RESTART
:
2342 if (sh
->pd_idx
== raid_disks
-1)
2343 i
--; /* Q D D D P */
2344 else if (i
> sh
->pd_idx
)
2345 i
-= 2; /* D D P Q D */
2347 case ALGORITHM_LEFT_SYMMETRIC
:
2348 case ALGORITHM_RIGHT_SYMMETRIC
:
2349 if (sh
->pd_idx
== raid_disks
-1)
2350 i
--; /* Q D D D P */
2355 i
-= (sh
->pd_idx
+ 2);
2358 case ALGORITHM_PARITY_0
:
2361 case ALGORITHM_PARITY_N
:
2363 case ALGORITHM_ROTATING_N_CONTINUE
:
2364 /* Like left_symmetric, but P is before Q */
2365 if (sh
->pd_idx
== 0)
2366 i
--; /* P D D D Q */
2371 i
-= (sh
->pd_idx
+ 1);
2374 case ALGORITHM_LEFT_ASYMMETRIC_6
:
2375 case ALGORITHM_RIGHT_ASYMMETRIC_6
:
2379 case ALGORITHM_LEFT_SYMMETRIC_6
:
2380 case ALGORITHM_RIGHT_SYMMETRIC_6
:
2382 i
+= data_disks
+ 1;
2383 i
-= (sh
->pd_idx
+ 1);
2385 case ALGORITHM_PARITY_0_6
:
2394 chunk_number
= stripe
* data_disks
+ i
;
2395 r_sector
= chunk_number
* sectors_per_chunk
+ chunk_offset
;
2397 check
= raid5_compute_sector(conf
, r_sector
,
2398 previous
, &dummy1
, &sh2
);
2399 if (check
!= sh
->sector
|| dummy1
!= dd_idx
|| sh2
.pd_idx
!= sh
->pd_idx
2400 || sh2
.qd_idx
!= sh
->qd_idx
) {
2401 printk(KERN_ERR
"md/raid:%s: compute_blocknr: map not correct\n",
2402 mdname(conf
->mddev
));
2410 schedule_reconstruction(struct stripe_head
*sh
, struct stripe_head_state
*s
,
2411 int rcw
, int expand
)
2413 int i
, pd_idx
= sh
->pd_idx
, disks
= sh
->disks
;
2414 struct r5conf
*conf
= sh
->raid_conf
;
2415 int level
= conf
->level
;
2419 for (i
= disks
; i
--; ) {
2420 struct r5dev
*dev
= &sh
->dev
[i
];
2423 set_bit(R5_LOCKED
, &dev
->flags
);
2424 set_bit(R5_Wantdrain
, &dev
->flags
);
2426 clear_bit(R5_UPTODATE
, &dev
->flags
);
2430 /* if we are not expanding this is a proper write request, and
2431 * there will be bios with new data to be drained into the
2436 /* False alarm, nothing to do */
2438 sh
->reconstruct_state
= reconstruct_state_drain_run
;
2439 set_bit(STRIPE_OP_BIODRAIN
, &s
->ops_request
);
2441 sh
->reconstruct_state
= reconstruct_state_run
;
2443 set_bit(STRIPE_OP_RECONSTRUCT
, &s
->ops_request
);
2445 if (s
->locked
+ conf
->max_degraded
== disks
)
2446 if (!test_and_set_bit(STRIPE_FULL_WRITE
, &sh
->state
))
2447 atomic_inc(&conf
->pending_full_writes
);
2450 BUG_ON(!(test_bit(R5_UPTODATE
, &sh
->dev
[pd_idx
].flags
) ||
2451 test_bit(R5_Wantcompute
, &sh
->dev
[pd_idx
].flags
)));
2453 for (i
= disks
; i
--; ) {
2454 struct r5dev
*dev
= &sh
->dev
[i
];
2459 (test_bit(R5_UPTODATE
, &dev
->flags
) ||
2460 test_bit(R5_Wantcompute
, &dev
->flags
))) {
2461 set_bit(R5_Wantdrain
, &dev
->flags
);
2462 set_bit(R5_LOCKED
, &dev
->flags
);
2463 clear_bit(R5_UPTODATE
, &dev
->flags
);
2468 /* False alarm - nothing to do */
2470 sh
->reconstruct_state
= reconstruct_state_prexor_drain_run
;
2471 set_bit(STRIPE_OP_PREXOR
, &s
->ops_request
);
2472 set_bit(STRIPE_OP_BIODRAIN
, &s
->ops_request
);
2473 set_bit(STRIPE_OP_RECONSTRUCT
, &s
->ops_request
);
2476 /* keep the parity disk(s) locked while asynchronous operations
2479 set_bit(R5_LOCKED
, &sh
->dev
[pd_idx
].flags
);
2480 clear_bit(R5_UPTODATE
, &sh
->dev
[pd_idx
].flags
);
2484 int qd_idx
= sh
->qd_idx
;
2485 struct r5dev
*dev
= &sh
->dev
[qd_idx
];
2487 set_bit(R5_LOCKED
, &dev
->flags
);
2488 clear_bit(R5_UPTODATE
, &dev
->flags
);
2492 pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
2493 __func__
, (unsigned long long)sh
->sector
,
2494 s
->locked
, s
->ops_request
);
2498 * Each stripe/dev can have one or more bion attached.
2499 * toread/towrite point to the first in a chain.
2500 * The bi_next chain must be in order.
2502 static int add_stripe_bio(struct stripe_head
*sh
, struct bio
*bi
, int dd_idx
, int forwrite
)
2505 struct r5conf
*conf
= sh
->raid_conf
;
2508 pr_debug("adding bi b#%llu to stripe s#%llu\n",
2509 (unsigned long long)bi
->bi_sector
,
2510 (unsigned long long)sh
->sector
);
2513 * If several bio share a stripe. The bio bi_phys_segments acts as a
2514 * reference count to avoid race. The reference count should already be
2515 * increased before this function is called (for example, in
2516 * make_request()), so other bio sharing this stripe will not free the
2517 * stripe. If a stripe is owned by one stripe, the stripe lock will
2520 spin_lock_irq(&sh
->stripe_lock
);
2522 bip
= &sh
->dev
[dd_idx
].towrite
;
2526 bip
= &sh
->dev
[dd_idx
].toread
;
2527 while (*bip
&& (*bip
)->bi_sector
< bi
->bi_sector
) {
2528 if (bio_end_sector(*bip
) > bi
->bi_sector
)
2530 bip
= & (*bip
)->bi_next
;
2532 if (*bip
&& (*bip
)->bi_sector
< bio_end_sector(bi
))
2535 BUG_ON(*bip
&& bi
->bi_next
&& (*bip
) != bi
->bi_next
);
2539 raid5_inc_bi_active_stripes(bi
);
2542 /* check if page is covered */
2543 sector_t sector
= sh
->dev
[dd_idx
].sector
;
2544 for (bi
=sh
->dev
[dd_idx
].towrite
;
2545 sector
< sh
->dev
[dd_idx
].sector
+ STRIPE_SECTORS
&&
2546 bi
&& bi
->bi_sector
<= sector
;
2547 bi
= r5_next_bio(bi
, sh
->dev
[dd_idx
].sector
)) {
2548 if (bio_end_sector(bi
) >= sector
)
2549 sector
= bio_end_sector(bi
);
2551 if (sector
>= sh
->dev
[dd_idx
].sector
+ STRIPE_SECTORS
)
2552 set_bit(R5_OVERWRITE
, &sh
->dev
[dd_idx
].flags
);
2555 pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
2556 (unsigned long long)(*bip
)->bi_sector
,
2557 (unsigned long long)sh
->sector
, dd_idx
);
2558 spin_unlock_irq(&sh
->stripe_lock
);
2560 if (conf
->mddev
->bitmap
&& firstwrite
) {
2561 bitmap_startwrite(conf
->mddev
->bitmap
, sh
->sector
,
2563 sh
->bm_seq
= conf
->seq_flush
+1;
2564 set_bit(STRIPE_BIT_DELAY
, &sh
->state
);
2569 set_bit(R5_Overlap
, &sh
->dev
[dd_idx
].flags
);
2570 spin_unlock_irq(&sh
->stripe_lock
);
2574 static void end_reshape(struct r5conf
*conf
);
2576 static void stripe_set_idx(sector_t stripe
, struct r5conf
*conf
, int previous
,
2577 struct stripe_head
*sh
)
2579 int sectors_per_chunk
=
2580 previous
? conf
->prev_chunk_sectors
: conf
->chunk_sectors
;
2582 int chunk_offset
= sector_div(stripe
, sectors_per_chunk
);
2583 int disks
= previous
? conf
->previous_raid_disks
: conf
->raid_disks
;
2585 raid5_compute_sector(conf
,
2586 stripe
* (disks
- conf
->max_degraded
)
2587 *sectors_per_chunk
+ chunk_offset
,
2593 handle_failed_stripe(struct r5conf
*conf
, struct stripe_head
*sh
,
2594 struct stripe_head_state
*s
, int disks
,
2595 struct bio
**return_bi
)
2598 for (i
= disks
; i
--; ) {
2602 if (test_bit(R5_ReadError
, &sh
->dev
[i
].flags
)) {
2603 struct md_rdev
*rdev
;
2605 rdev
= rcu_dereference(conf
->disks
[i
].rdev
);
2606 if (rdev
&& test_bit(In_sync
, &rdev
->flags
))
2607 atomic_inc(&rdev
->nr_pending
);
2612 if (!rdev_set_badblocks(
2616 md_error(conf
->mddev
, rdev
);
2617 rdev_dec_pending(rdev
, conf
->mddev
);
2620 spin_lock_irq(&sh
->stripe_lock
);
2621 /* fail all writes first */
2622 bi
= sh
->dev
[i
].towrite
;
2623 sh
->dev
[i
].towrite
= NULL
;
2624 spin_unlock_irq(&sh
->stripe_lock
);
2628 if (test_and_clear_bit(R5_Overlap
, &sh
->dev
[i
].flags
))
2629 wake_up(&conf
->wait_for_overlap
);
2631 while (bi
&& bi
->bi_sector
<
2632 sh
->dev
[i
].sector
+ STRIPE_SECTORS
) {
2633 struct bio
*nextbi
= r5_next_bio(bi
, sh
->dev
[i
].sector
);
2634 clear_bit(BIO_UPTODATE
, &bi
->bi_flags
);
2635 if (!raid5_dec_bi_active_stripes(bi
)) {
2636 md_write_end(conf
->mddev
);
2637 bi
->bi_next
= *return_bi
;
2643 bitmap_endwrite(conf
->mddev
->bitmap
, sh
->sector
,
2644 STRIPE_SECTORS
, 0, 0);
2646 /* and fail all 'written' */
2647 bi
= sh
->dev
[i
].written
;
2648 sh
->dev
[i
].written
= NULL
;
2649 if (bi
) bitmap_end
= 1;
2650 while (bi
&& bi
->bi_sector
<
2651 sh
->dev
[i
].sector
+ STRIPE_SECTORS
) {
2652 struct bio
*bi2
= r5_next_bio(bi
, sh
->dev
[i
].sector
);
2653 clear_bit(BIO_UPTODATE
, &bi
->bi_flags
);
2654 if (!raid5_dec_bi_active_stripes(bi
)) {
2655 md_write_end(conf
->mddev
);
2656 bi
->bi_next
= *return_bi
;
2662 /* fail any reads if this device is non-operational and
2663 * the data has not reached the cache yet.
2665 if (!test_bit(R5_Wantfill
, &sh
->dev
[i
].flags
) &&
2666 (!test_bit(R5_Insync
, &sh
->dev
[i
].flags
) ||
2667 test_bit(R5_ReadError
, &sh
->dev
[i
].flags
))) {
2668 spin_lock_irq(&sh
->stripe_lock
);
2669 bi
= sh
->dev
[i
].toread
;
2670 sh
->dev
[i
].toread
= NULL
;
2671 spin_unlock_irq(&sh
->stripe_lock
);
2672 if (test_and_clear_bit(R5_Overlap
, &sh
->dev
[i
].flags
))
2673 wake_up(&conf
->wait_for_overlap
);
2674 while (bi
&& bi
->bi_sector
<
2675 sh
->dev
[i
].sector
+ STRIPE_SECTORS
) {
2676 struct bio
*nextbi
=
2677 r5_next_bio(bi
, sh
->dev
[i
].sector
);
2678 clear_bit(BIO_UPTODATE
, &bi
->bi_flags
);
2679 if (!raid5_dec_bi_active_stripes(bi
)) {
2680 bi
->bi_next
= *return_bi
;
2687 bitmap_endwrite(conf
->mddev
->bitmap
, sh
->sector
,
2688 STRIPE_SECTORS
, 0, 0);
2689 /* If we were in the middle of a write the parity block might
2690 * still be locked - so just clear all R5_LOCKED flags
2692 clear_bit(R5_LOCKED
, &sh
->dev
[i
].flags
);
2695 if (test_and_clear_bit(STRIPE_FULL_WRITE
, &sh
->state
))
2696 if (atomic_dec_and_test(&conf
->pending_full_writes
))
2697 md_wakeup_thread(conf
->mddev
->thread
);
2701 handle_failed_sync(struct r5conf
*conf
, struct stripe_head
*sh
,
2702 struct stripe_head_state
*s
)
2707 clear_bit(STRIPE_SYNCING
, &sh
->state
);
2708 if (test_and_clear_bit(R5_Overlap
, &sh
->dev
[sh
->pd_idx
].flags
))
2709 wake_up(&conf
->wait_for_overlap
);
2712 /* There is nothing more to do for sync/check/repair.
2713 * Don't even need to abort as that is handled elsewhere
2714 * if needed, and not always wanted e.g. if there is a known
2716 * For recover/replace we need to record a bad block on all
2717 * non-sync devices, or abort the recovery
2719 if (test_bit(MD_RECOVERY_RECOVER
, &conf
->mddev
->recovery
)) {
2720 /* During recovery devices cannot be removed, so
2721 * locking and refcounting of rdevs is not needed
2723 for (i
= 0; i
< conf
->raid_disks
; i
++) {
2724 struct md_rdev
*rdev
= conf
->disks
[i
].rdev
;
2726 && !test_bit(Faulty
, &rdev
->flags
)
2727 && !test_bit(In_sync
, &rdev
->flags
)
2728 && !rdev_set_badblocks(rdev
, sh
->sector
,
2731 rdev
= conf
->disks
[i
].replacement
;
2733 && !test_bit(Faulty
, &rdev
->flags
)
2734 && !test_bit(In_sync
, &rdev
->flags
)
2735 && !rdev_set_badblocks(rdev
, sh
->sector
,
2740 conf
->recovery_disabled
=
2741 conf
->mddev
->recovery_disabled
;
2743 md_done_sync(conf
->mddev
, STRIPE_SECTORS
, !abort
);
2746 static int want_replace(struct stripe_head
*sh
, int disk_idx
)
2748 struct md_rdev
*rdev
;
2750 /* Doing recovery so rcu locking not required */
2751 rdev
= sh
->raid_conf
->disks
[disk_idx
].replacement
;
2753 && !test_bit(Faulty
, &rdev
->flags
)
2754 && !test_bit(In_sync
, &rdev
->flags
)
2755 && (rdev
->recovery_offset
<= sh
->sector
2756 || rdev
->mddev
->recovery_cp
<= sh
->sector
))
2762 /* fetch_block - checks the given member device to see if its data needs
2763 * to be read or computed to satisfy a request.
2765 * Returns 1 when no more member devices need to be checked, otherwise returns
2766 * 0 to tell the loop in handle_stripe_fill to continue
2768 static int fetch_block(struct stripe_head
*sh
, struct stripe_head_state
*s
,
2769 int disk_idx
, int disks
)
2771 struct r5dev
*dev
= &sh
->dev
[disk_idx
];
2772 struct r5dev
*fdev
[2] = { &sh
->dev
[s
->failed_num
[0]],
2773 &sh
->dev
[s
->failed_num
[1]] };
2775 /* is the data in this block needed, and can we get it? */
2776 if (!test_bit(R5_LOCKED
, &dev
->flags
) &&
2777 !test_bit(R5_UPTODATE
, &dev
->flags
) &&
2779 (dev
->towrite
&& !test_bit(R5_OVERWRITE
, &dev
->flags
)) ||
2780 s
->syncing
|| s
->expanding
||
2781 (s
->replacing
&& want_replace(sh
, disk_idx
)) ||
2782 (s
->failed
>= 1 && fdev
[0]->toread
) ||
2783 (s
->failed
>= 2 && fdev
[1]->toread
) ||
2784 (sh
->raid_conf
->level
<= 5 && s
->failed
&& fdev
[0]->towrite
&&
2785 !test_bit(R5_OVERWRITE
, &fdev
[0]->flags
)) ||
2786 (sh
->raid_conf
->level
== 6 && s
->failed
&& s
->to_write
))) {
2787 /* we would like to get this block, possibly by computing it,
2788 * otherwise read it if the backing disk is insync
2790 BUG_ON(test_bit(R5_Wantcompute
, &dev
->flags
));
2791 BUG_ON(test_bit(R5_Wantread
, &dev
->flags
));
2792 if ((s
->uptodate
== disks
- 1) &&
2793 (s
->failed
&& (disk_idx
== s
->failed_num
[0] ||
2794 disk_idx
== s
->failed_num
[1]))) {
2795 /* have disk failed, and we're requested to fetch it;
2798 pr_debug("Computing stripe %llu block %d\n",
2799 (unsigned long long)sh
->sector
, disk_idx
);
2800 set_bit(STRIPE_COMPUTE_RUN
, &sh
->state
);
2801 set_bit(STRIPE_OP_COMPUTE_BLK
, &s
->ops_request
);
2802 set_bit(R5_Wantcompute
, &dev
->flags
);
2803 sh
->ops
.target
= disk_idx
;
2804 sh
->ops
.target2
= -1; /* no 2nd target */
2806 /* Careful: from this point on 'uptodate' is in the eye
2807 * of raid_run_ops which services 'compute' operations
2808 * before writes. R5_Wantcompute flags a block that will
2809 * be R5_UPTODATE by the time it is needed for a
2810 * subsequent operation.
2814 } else if (s
->uptodate
== disks
-2 && s
->failed
>= 2) {
2815 /* Computing 2-failure is *very* expensive; only
2816 * do it if failed >= 2
2819 for (other
= disks
; other
--; ) {
2820 if (other
== disk_idx
)
2822 if (!test_bit(R5_UPTODATE
,
2823 &sh
->dev
[other
].flags
))
2827 pr_debug("Computing stripe %llu blocks %d,%d\n",
2828 (unsigned long long)sh
->sector
,
2830 set_bit(STRIPE_COMPUTE_RUN
, &sh
->state
);
2831 set_bit(STRIPE_OP_COMPUTE_BLK
, &s
->ops_request
);
2832 set_bit(R5_Wantcompute
, &sh
->dev
[disk_idx
].flags
);
2833 set_bit(R5_Wantcompute
, &sh
->dev
[other
].flags
);
2834 sh
->ops
.target
= disk_idx
;
2835 sh
->ops
.target2
= other
;
2839 } else if (test_bit(R5_Insync
, &dev
->flags
)) {
2840 set_bit(R5_LOCKED
, &dev
->flags
);
2841 set_bit(R5_Wantread
, &dev
->flags
);
2843 pr_debug("Reading block %d (sync=%d)\n",
2844 disk_idx
, s
->syncing
);
2852 * handle_stripe_fill - read or compute data to satisfy pending requests.
2854 static void handle_stripe_fill(struct stripe_head
*sh
,
2855 struct stripe_head_state
*s
,
2860 /* look for blocks to read/compute, skip this if a compute
2861 * is already in flight, or if the stripe contents are in the
2862 * midst of changing due to a write
2864 if (!test_bit(STRIPE_COMPUTE_RUN
, &sh
->state
) && !sh
->check_state
&&
2865 !sh
->reconstruct_state
)
2866 for (i
= disks
; i
--; )
2867 if (fetch_block(sh
, s
, i
, disks
))
2869 set_bit(STRIPE_HANDLE
, &sh
->state
);
2873 /* handle_stripe_clean_event
2874 * any written block on an uptodate or failed drive can be returned.
2875 * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
2876 * never LOCKED, so we don't need to test 'failed' directly.
2878 static void handle_stripe_clean_event(struct r5conf
*conf
,
2879 struct stripe_head
*sh
, int disks
, struct bio
**return_bi
)
2883 int discard_pending
= 0;
2885 for (i
= disks
; i
--; )
2886 if (sh
->dev
[i
].written
) {
2888 if (!test_bit(R5_LOCKED
, &dev
->flags
) &&
2889 (test_bit(R5_UPTODATE
, &dev
->flags
) ||
2890 test_bit(R5_Discard
, &dev
->flags
))) {
2891 /* We can return any write requests */
2892 struct bio
*wbi
, *wbi2
;
2893 pr_debug("Return write for disc %d\n", i
);
2894 if (test_and_clear_bit(R5_Discard
, &dev
->flags
))
2895 clear_bit(R5_UPTODATE
, &dev
->flags
);
2897 dev
->written
= NULL
;
2898 while (wbi
&& wbi
->bi_sector
<
2899 dev
->sector
+ STRIPE_SECTORS
) {
2900 wbi2
= r5_next_bio(wbi
, dev
->sector
);
2901 if (!raid5_dec_bi_active_stripes(wbi
)) {
2902 md_write_end(conf
->mddev
);
2903 wbi
->bi_next
= *return_bi
;
2908 bitmap_endwrite(conf
->mddev
->bitmap
, sh
->sector
,
2910 !test_bit(STRIPE_DEGRADED
, &sh
->state
),
2912 } else if (test_bit(R5_Discard
, &dev
->flags
))
2913 discard_pending
= 1;
2915 if (!discard_pending
&&
2916 test_bit(R5_Discard
, &sh
->dev
[sh
->pd_idx
].flags
)) {
2917 clear_bit(R5_Discard
, &sh
->dev
[sh
->pd_idx
].flags
);
2918 clear_bit(R5_UPTODATE
, &sh
->dev
[sh
->pd_idx
].flags
);
2919 if (sh
->qd_idx
>= 0) {
2920 clear_bit(R5_Discard
, &sh
->dev
[sh
->qd_idx
].flags
);
2921 clear_bit(R5_UPTODATE
, &sh
->dev
[sh
->qd_idx
].flags
);
2923 /* now that discard is done we can proceed with any sync */
2924 clear_bit(STRIPE_DISCARD
, &sh
->state
);
2926 * SCSI discard will change some bio fields and the stripe has
2927 * no updated data, so remove it from hash list and the stripe
2928 * will be reinitialized
2930 spin_lock_irq(&conf
->device_lock
);
2932 spin_unlock_irq(&conf
->device_lock
);
2933 if (test_bit(STRIPE_SYNC_REQUESTED
, &sh
->state
))
2934 set_bit(STRIPE_HANDLE
, &sh
->state
);
2938 if (test_and_clear_bit(STRIPE_FULL_WRITE
, &sh
->state
))
2939 if (atomic_dec_and_test(&conf
->pending_full_writes
))
2940 md_wakeup_thread(conf
->mddev
->thread
);
2943 static void handle_stripe_dirtying(struct r5conf
*conf
,
2944 struct stripe_head
*sh
,
2945 struct stripe_head_state
*s
,
2948 int rmw
= 0, rcw
= 0, i
;
2949 sector_t recovery_cp
= conf
->mddev
->recovery_cp
;
2951 /* RAID6 requires 'rcw' in current implementation.
2952 * Otherwise, check whether resync is now happening or should start.
2953 * If yes, then the array is dirty (after unclean shutdown or
2954 * initial creation), so parity in some stripes might be inconsistent.
2955 * In this case, we need to always do reconstruct-write, to ensure
2956 * that in case of drive failure or read-error correction, we
2957 * generate correct data from the parity.
2959 if (conf
->max_degraded
== 2 ||
2960 (recovery_cp
< MaxSector
&& sh
->sector
>= recovery_cp
)) {
2961 /* Calculate the real rcw later - for now make it
2962 * look like rcw is cheaper
2965 pr_debug("force RCW max_degraded=%u, recovery_cp=%llu sh->sector=%llu\n",
2966 conf
->max_degraded
, (unsigned long long)recovery_cp
,
2967 (unsigned long long)sh
->sector
);
2968 } else for (i
= disks
; i
--; ) {
2969 /* would I have to read this buffer for read_modify_write */
2970 struct r5dev
*dev
= &sh
->dev
[i
];
2971 if ((dev
->towrite
|| i
== sh
->pd_idx
) &&
2972 !test_bit(R5_LOCKED
, &dev
->flags
) &&
2973 !(test_bit(R5_UPTODATE
, &dev
->flags
) ||
2974 test_bit(R5_Wantcompute
, &dev
->flags
))) {
2975 if (test_bit(R5_Insync
, &dev
->flags
))
2978 rmw
+= 2*disks
; /* cannot read it */
2980 /* Would I have to read this buffer for reconstruct_write */
2981 if (!test_bit(R5_OVERWRITE
, &dev
->flags
) && i
!= sh
->pd_idx
&&
2982 !test_bit(R5_LOCKED
, &dev
->flags
) &&
2983 !(test_bit(R5_UPTODATE
, &dev
->flags
) ||
2984 test_bit(R5_Wantcompute
, &dev
->flags
))) {
2985 if (test_bit(R5_Insync
, &dev
->flags
)) rcw
++;
2990 pr_debug("for sector %llu, rmw=%d rcw=%d\n",
2991 (unsigned long long)sh
->sector
, rmw
, rcw
);
2992 set_bit(STRIPE_HANDLE
, &sh
->state
);
2993 if (rmw
< rcw
&& rmw
> 0) {
2994 /* prefer read-modify-write, but need to get some data */
2995 if (conf
->mddev
->queue
)
2996 blk_add_trace_msg(conf
->mddev
->queue
,
2997 "raid5 rmw %llu %d",
2998 (unsigned long long)sh
->sector
, rmw
);
2999 for (i
= disks
; i
--; ) {
3000 struct r5dev
*dev
= &sh
->dev
[i
];
3001 if ((dev
->towrite
|| i
== sh
->pd_idx
) &&
3002 !test_bit(R5_LOCKED
, &dev
->flags
) &&
3003 !(test_bit(R5_UPTODATE
, &dev
->flags
) ||
3004 test_bit(R5_Wantcompute
, &dev
->flags
)) &&
3005 test_bit(R5_Insync
, &dev
->flags
)) {
3007 test_bit(STRIPE_PREREAD_ACTIVE
, &sh
->state
)) {
3008 pr_debug("Read_old block "
3009 "%d for r-m-w\n", i
);
3010 set_bit(R5_LOCKED
, &dev
->flags
);
3011 set_bit(R5_Wantread
, &dev
->flags
);
3014 set_bit(STRIPE_DELAYED
, &sh
->state
);
3015 set_bit(STRIPE_HANDLE
, &sh
->state
);
3020 if (rcw
<= rmw
&& rcw
> 0) {
3021 /* want reconstruct write, but need to get some data */
3024 for (i
= disks
; i
--; ) {
3025 struct r5dev
*dev
= &sh
->dev
[i
];
3026 if (!test_bit(R5_OVERWRITE
, &dev
->flags
) &&
3027 i
!= sh
->pd_idx
&& i
!= sh
->qd_idx
&&
3028 !test_bit(R5_LOCKED
, &dev
->flags
) &&
3029 !(test_bit(R5_UPTODATE
, &dev
->flags
) ||
3030 test_bit(R5_Wantcompute
, &dev
->flags
))) {
3032 if (!test_bit(R5_Insync
, &dev
->flags
))
3033 continue; /* it's a failed drive */
3035 test_bit(STRIPE_PREREAD_ACTIVE
, &sh
->state
)) {
3036 pr_debug("Read_old block "
3037 "%d for Reconstruct\n", i
);
3038 set_bit(R5_LOCKED
, &dev
->flags
);
3039 set_bit(R5_Wantread
, &dev
->flags
);
3043 set_bit(STRIPE_DELAYED
, &sh
->state
);
3044 set_bit(STRIPE_HANDLE
, &sh
->state
);
3048 if (rcw
&& conf
->mddev
->queue
)
3049 blk_add_trace_msg(conf
->mddev
->queue
, "raid5 rcw %llu %d %d %d",
3050 (unsigned long long)sh
->sector
,
3051 rcw
, qread
, test_bit(STRIPE_DELAYED
, &sh
->state
));
3053 /* now if nothing is locked, and if we have enough data,
3054 * we can start a write request
3056 /* since handle_stripe can be called at any time we need to handle the
3057 * case where a compute block operation has been submitted and then a
3058 * subsequent call wants to start a write request. raid_run_ops only
3059 * handles the case where compute block and reconstruct are requested
3060 * simultaneously. If this is not the case then new writes need to be
3061 * held off until the compute completes.
3063 if ((s
->req_compute
|| !test_bit(STRIPE_COMPUTE_RUN
, &sh
->state
)) &&
3064 (s
->locked
== 0 && (rcw
== 0 || rmw
== 0) &&
3065 !test_bit(STRIPE_BIT_DELAY
, &sh
->state
)))
3066 schedule_reconstruction(sh
, s
, rcw
== 0, 0);
3069 static void handle_parity_checks5(struct r5conf
*conf
, struct stripe_head
*sh
,
3070 struct stripe_head_state
*s
, int disks
)
3072 struct r5dev
*dev
= NULL
;
3074 set_bit(STRIPE_HANDLE
, &sh
->state
);
3076 switch (sh
->check_state
) {
3077 case check_state_idle
:
3078 /* start a new check operation if there are no failures */
3079 if (s
->failed
== 0) {
3080 BUG_ON(s
->uptodate
!= disks
);
3081 sh
->check_state
= check_state_run
;
3082 set_bit(STRIPE_OP_CHECK
, &s
->ops_request
);
3083 clear_bit(R5_UPTODATE
, &sh
->dev
[sh
->pd_idx
].flags
);
3087 dev
= &sh
->dev
[s
->failed_num
[0]];
3089 case check_state_compute_result
:
3090 sh
->check_state
= check_state_idle
;
3092 dev
= &sh
->dev
[sh
->pd_idx
];
3094 /* check that a write has not made the stripe insync */
3095 if (test_bit(STRIPE_INSYNC
, &sh
->state
))
3098 /* either failed parity check, or recovery is happening */
3099 BUG_ON(!test_bit(R5_UPTODATE
, &dev
->flags
));
3100 BUG_ON(s
->uptodate
!= disks
);
3102 set_bit(R5_LOCKED
, &dev
->flags
);
3104 set_bit(R5_Wantwrite
, &dev
->flags
);
3106 clear_bit(STRIPE_DEGRADED
, &sh
->state
);
3107 set_bit(STRIPE_INSYNC
, &sh
->state
);
3109 case check_state_run
:
3110 break; /* we will be called again upon completion */
3111 case check_state_check_result
:
3112 sh
->check_state
= check_state_idle
;
3114 /* if a failure occurred during the check operation, leave
3115 * STRIPE_INSYNC not set and let the stripe be handled again
3120 /* handle a successful check operation, if parity is correct
3121 * we are done. Otherwise update the mismatch count and repair
3122 * parity if !MD_RECOVERY_CHECK
3124 if ((sh
->ops
.zero_sum_result
& SUM_CHECK_P_RESULT
) == 0)
3125 /* parity is correct (on disc,
3126 * not in buffer any more)
3128 set_bit(STRIPE_INSYNC
, &sh
->state
);
3130 atomic64_add(STRIPE_SECTORS
, &conf
->mddev
->resync_mismatches
);
3131 if (test_bit(MD_RECOVERY_CHECK
, &conf
->mddev
->recovery
))
3132 /* don't try to repair!! */
3133 set_bit(STRIPE_INSYNC
, &sh
->state
);
3135 sh
->check_state
= check_state_compute_run
;
3136 set_bit(STRIPE_COMPUTE_RUN
, &sh
->state
);
3137 set_bit(STRIPE_OP_COMPUTE_BLK
, &s
->ops_request
);
3138 set_bit(R5_Wantcompute
,
3139 &sh
->dev
[sh
->pd_idx
].flags
);
3140 sh
->ops
.target
= sh
->pd_idx
;
3141 sh
->ops
.target2
= -1;
3146 case check_state_compute_run
:
3149 printk(KERN_ERR
"%s: unknown check_state: %d sector: %llu\n",
3150 __func__
, sh
->check_state
,
3151 (unsigned long long) sh
->sector
);
3157 static void handle_parity_checks6(struct r5conf
*conf
, struct stripe_head
*sh
,
3158 struct stripe_head_state
*s
,
3161 int pd_idx
= sh
->pd_idx
;
3162 int qd_idx
= sh
->qd_idx
;
3165 set_bit(STRIPE_HANDLE
, &sh
->state
);
3167 BUG_ON(s
->failed
> 2);
3169 /* Want to check and possibly repair P and Q.
3170 * However there could be one 'failed' device, in which
3171 * case we can only check one of them, possibly using the
3172 * other to generate missing data
3175 switch (sh
->check_state
) {
3176 case check_state_idle
:
3177 /* start a new check operation if there are < 2 failures */
3178 if (s
->failed
== s
->q_failed
) {
3179 /* The only possible failed device holds Q, so it
3180 * makes sense to check P (If anything else were failed,
3181 * we would have used P to recreate it).
3183 sh
->check_state
= check_state_run
;
3185 if (!s
->q_failed
&& s
->failed
< 2) {
3186 /* Q is not failed, and we didn't use it to generate
3187 * anything, so it makes sense to check it
3189 if (sh
->check_state
== check_state_run
)
3190 sh
->check_state
= check_state_run_pq
;
3192 sh
->check_state
= check_state_run_q
;
3195 /* discard potentially stale zero_sum_result */
3196 sh
->ops
.zero_sum_result
= 0;
3198 if (sh
->check_state
== check_state_run
) {
3199 /* async_xor_zero_sum destroys the contents of P */
3200 clear_bit(R5_UPTODATE
, &sh
->dev
[pd_idx
].flags
);
3203 if (sh
->check_state
>= check_state_run
&&
3204 sh
->check_state
<= check_state_run_pq
) {
3205 /* async_syndrome_zero_sum preserves P and Q, so
3206 * no need to mark them !uptodate here
3208 set_bit(STRIPE_OP_CHECK
, &s
->ops_request
);
3212 /* we have 2-disk failure */
3213 BUG_ON(s
->failed
!= 2);
3215 case check_state_compute_result
:
3216 sh
->check_state
= check_state_idle
;
3218 /* check that a write has not made the stripe insync */
3219 if (test_bit(STRIPE_INSYNC
, &sh
->state
))
3222 /* now write out any block on a failed drive,
3223 * or P or Q if they were recomputed
3225 BUG_ON(s
->uptodate
< disks
- 1); /* We don't need Q to recover */
3226 if (s
->failed
== 2) {
3227 dev
= &sh
->dev
[s
->failed_num
[1]];
3229 set_bit(R5_LOCKED
, &dev
->flags
);
3230 set_bit(R5_Wantwrite
, &dev
->flags
);
3232 if (s
->failed
>= 1) {
3233 dev
= &sh
->dev
[s
->failed_num
[0]];
3235 set_bit(R5_LOCKED
, &dev
->flags
);
3236 set_bit(R5_Wantwrite
, &dev
->flags
);
3238 if (sh
->ops
.zero_sum_result
& SUM_CHECK_P_RESULT
) {
3239 dev
= &sh
->dev
[pd_idx
];
3241 set_bit(R5_LOCKED
, &dev
->flags
);
3242 set_bit(R5_Wantwrite
, &dev
->flags
);
3244 if (sh
->ops
.zero_sum_result
& SUM_CHECK_Q_RESULT
) {
3245 dev
= &sh
->dev
[qd_idx
];
3247 set_bit(R5_LOCKED
, &dev
->flags
);
3248 set_bit(R5_Wantwrite
, &dev
->flags
);
3250 clear_bit(STRIPE_DEGRADED
, &sh
->state
);
3252 set_bit(STRIPE_INSYNC
, &sh
->state
);
3254 case check_state_run
:
3255 case check_state_run_q
:
3256 case check_state_run_pq
:
3257 break; /* we will be called again upon completion */
3258 case check_state_check_result
:
3259 sh
->check_state
= check_state_idle
;
3261 /* handle a successful check operation, if parity is correct
3262 * we are done. Otherwise update the mismatch count and repair
3263 * parity if !MD_RECOVERY_CHECK
3265 if (sh
->ops
.zero_sum_result
== 0) {
3266 /* both parities are correct */
3268 set_bit(STRIPE_INSYNC
, &sh
->state
);
3270 /* in contrast to the raid5 case we can validate
3271 * parity, but still have a failure to write
3274 sh
->check_state
= check_state_compute_result
;
3275 /* Returning at this point means that we may go
3276 * off and bring p and/or q uptodate again so
3277 * we make sure to check zero_sum_result again
3278 * to verify if p or q need writeback
3282 atomic64_add(STRIPE_SECTORS
, &conf
->mddev
->resync_mismatches
);
3283 if (test_bit(MD_RECOVERY_CHECK
, &conf
->mddev
->recovery
))
3284 /* don't try to repair!! */
3285 set_bit(STRIPE_INSYNC
, &sh
->state
);
3287 int *target
= &sh
->ops
.target
;
3289 sh
->ops
.target
= -1;
3290 sh
->ops
.target2
= -1;
3291 sh
->check_state
= check_state_compute_run
;
3292 set_bit(STRIPE_COMPUTE_RUN
, &sh
->state
);
3293 set_bit(STRIPE_OP_COMPUTE_BLK
, &s
->ops_request
);
3294 if (sh
->ops
.zero_sum_result
& SUM_CHECK_P_RESULT
) {
3295 set_bit(R5_Wantcompute
,
3296 &sh
->dev
[pd_idx
].flags
);
3298 target
= &sh
->ops
.target2
;
3301 if (sh
->ops
.zero_sum_result
& SUM_CHECK_Q_RESULT
) {
3302 set_bit(R5_Wantcompute
,
3303 &sh
->dev
[qd_idx
].flags
);
3310 case check_state_compute_run
:
3313 printk(KERN_ERR
"%s: unknown check_state: %d sector: %llu\n",
3314 __func__
, sh
->check_state
,
3315 (unsigned long long) sh
->sector
);
3320 static void handle_stripe_expansion(struct r5conf
*conf
, struct stripe_head
*sh
)
3324 /* We have read all the blocks in this stripe and now we need to
3325 * copy some of them into a target stripe for expand.
3327 struct dma_async_tx_descriptor
*tx
= NULL
;
3328 clear_bit(STRIPE_EXPAND_SOURCE
, &sh
->state
);
3329 for (i
= 0; i
< sh
->disks
; i
++)
3330 if (i
!= sh
->pd_idx
&& i
!= sh
->qd_idx
) {
3332 struct stripe_head
*sh2
;
3333 struct async_submit_ctl submit
;
3335 sector_t bn
= compute_blocknr(sh
, i
, 1);
3336 sector_t s
= raid5_compute_sector(conf
, bn
, 0,
3338 sh2
= get_active_stripe(conf
, s
, 0, 1, 1);
3340 /* so far only the early blocks of this stripe
3341 * have been requested. When later blocks
3342 * get requested, we will try again
3345 if (!test_bit(STRIPE_EXPANDING
, &sh2
->state
) ||
3346 test_bit(R5_Expanded
, &sh2
->dev
[dd_idx
].flags
)) {
3347 /* must have already done this block */
3348 release_stripe(sh2
);
3352 /* place all the copies on one channel */
3353 init_async_submit(&submit
, 0, tx
, NULL
, NULL
, NULL
);
3354 tx
= async_memcpy(sh2
->dev
[dd_idx
].page
,
3355 sh
->dev
[i
].page
, 0, 0, STRIPE_SIZE
,
3358 set_bit(R5_Expanded
, &sh2
->dev
[dd_idx
].flags
);
3359 set_bit(R5_UPTODATE
, &sh2
->dev
[dd_idx
].flags
);
3360 for (j
= 0; j
< conf
->raid_disks
; j
++)
3361 if (j
!= sh2
->pd_idx
&&
3363 !test_bit(R5_Expanded
, &sh2
->dev
[j
].flags
))
3365 if (j
== conf
->raid_disks
) {
3366 set_bit(STRIPE_EXPAND_READY
, &sh2
->state
);
3367 set_bit(STRIPE_HANDLE
, &sh2
->state
);
3369 release_stripe(sh2
);
3372 /* done submitting copies, wait for them to complete */
3373 async_tx_quiesce(&tx
);
3377 * handle_stripe - do things to a stripe.
3379 * We lock the stripe by setting STRIPE_ACTIVE and then examine the
3380 * state of various bits to see what needs to be done.
3382 * return some read requests which now have data
3383 * return some write requests which are safely on storage
3384 * schedule a read on some buffers
3385 * schedule a write of some buffers
3386 * return confirmation of parity correctness
3390 static void analyse_stripe(struct stripe_head
*sh
, struct stripe_head_state
*s
)
3392 struct r5conf
*conf
= sh
->raid_conf
;
3393 int disks
= sh
->disks
;
3396 int do_recovery
= 0;
3398 memset(s
, 0, sizeof(*s
));
3400 s
->expanding
= test_bit(STRIPE_EXPAND_SOURCE
, &sh
->state
);
3401 s
->expanded
= test_bit(STRIPE_EXPAND_READY
, &sh
->state
);
3402 s
->failed_num
[0] = -1;
3403 s
->failed_num
[1] = -1;
3405 /* Now to look around and see what can be done */
3407 for (i
=disks
; i
--; ) {
3408 struct md_rdev
*rdev
;
3415 pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
3417 dev
->toread
, dev
->towrite
, dev
->written
);
3418 /* maybe we can reply to a read
3420 * new wantfill requests are only permitted while
3421 * ops_complete_biofill is guaranteed to be inactive
3423 if (test_bit(R5_UPTODATE
, &dev
->flags
) && dev
->toread
&&
3424 !test_bit(STRIPE_BIOFILL_RUN
, &sh
->state
))
3425 set_bit(R5_Wantfill
, &dev
->flags
);
3427 /* now count some things */
3428 if (test_bit(R5_LOCKED
, &dev
->flags
))
3430 if (test_bit(R5_UPTODATE
, &dev
->flags
))
3432 if (test_bit(R5_Wantcompute
, &dev
->flags
)) {
3434 BUG_ON(s
->compute
> 2);
3437 if (test_bit(R5_Wantfill
, &dev
->flags
))
3439 else if (dev
->toread
)
3443 if (!test_bit(R5_OVERWRITE
, &dev
->flags
))
3448 /* Prefer to use the replacement for reads, but only
3449 * if it is recovered enough and has no bad blocks.
3451 rdev
= rcu_dereference(conf
->disks
[i
].replacement
);
3452 if (rdev
&& !test_bit(Faulty
, &rdev
->flags
) &&
3453 rdev
->recovery_offset
>= sh
->sector
+ STRIPE_SECTORS
&&
3454 !is_badblock(rdev
, sh
->sector
, STRIPE_SECTORS
,
3455 &first_bad
, &bad_sectors
))
3456 set_bit(R5_ReadRepl
, &dev
->flags
);
3459 set_bit(R5_NeedReplace
, &dev
->flags
);
3460 rdev
= rcu_dereference(conf
->disks
[i
].rdev
);
3461 clear_bit(R5_ReadRepl
, &dev
->flags
);
3463 if (rdev
&& test_bit(Faulty
, &rdev
->flags
))
3466 is_bad
= is_badblock(rdev
, sh
->sector
, STRIPE_SECTORS
,
3467 &first_bad
, &bad_sectors
);
3468 if (s
->blocked_rdev
== NULL
3469 && (test_bit(Blocked
, &rdev
->flags
)
3472 set_bit(BlockedBadBlocks
,
3474 s
->blocked_rdev
= rdev
;
3475 atomic_inc(&rdev
->nr_pending
);
3478 clear_bit(R5_Insync
, &dev
->flags
);
3482 /* also not in-sync */
3483 if (!test_bit(WriteErrorSeen
, &rdev
->flags
) &&
3484 test_bit(R5_UPTODATE
, &dev
->flags
)) {
3485 /* treat as in-sync, but with a read error
3486 * which we can now try to correct
3488 set_bit(R5_Insync
, &dev
->flags
);
3489 set_bit(R5_ReadError
, &dev
->flags
);
3491 } else if (test_bit(In_sync
, &rdev
->flags
))
3492 set_bit(R5_Insync
, &dev
->flags
);
3493 else if (sh
->sector
+ STRIPE_SECTORS
<= rdev
->recovery_offset
)
3494 /* in sync if before recovery_offset */
3495 set_bit(R5_Insync
, &dev
->flags
);
3496 else if (test_bit(R5_UPTODATE
, &dev
->flags
) &&
3497 test_bit(R5_Expanded
, &dev
->flags
))
3498 /* If we've reshaped into here, we assume it is Insync.
3499 * We will shortly update recovery_offset to make
3502 set_bit(R5_Insync
, &dev
->flags
);
3504 if (rdev
&& test_bit(R5_WriteError
, &dev
->flags
)) {
3505 /* This flag does not apply to '.replacement'
3506 * only to .rdev, so make sure to check that*/
3507 struct md_rdev
*rdev2
= rcu_dereference(
3508 conf
->disks
[i
].rdev
);
3510 clear_bit(R5_Insync
, &dev
->flags
);
3511 if (rdev2
&& !test_bit(Faulty
, &rdev2
->flags
)) {
3512 s
->handle_bad_blocks
= 1;
3513 atomic_inc(&rdev2
->nr_pending
);
3515 clear_bit(R5_WriteError
, &dev
->flags
);
3517 if (rdev
&& test_bit(R5_MadeGood
, &dev
->flags
)) {
3518 /* This flag does not apply to '.replacement'
3519 * only to .rdev, so make sure to check that*/
3520 struct md_rdev
*rdev2
= rcu_dereference(
3521 conf
->disks
[i
].rdev
);
3522 if (rdev2
&& !test_bit(Faulty
, &rdev2
->flags
)) {
3523 s
->handle_bad_blocks
= 1;
3524 atomic_inc(&rdev2
->nr_pending
);
3526 clear_bit(R5_MadeGood
, &dev
->flags
);
3528 if (test_bit(R5_MadeGoodRepl
, &dev
->flags
)) {
3529 struct md_rdev
*rdev2
= rcu_dereference(
3530 conf
->disks
[i
].replacement
);
3531 if (rdev2
&& !test_bit(Faulty
, &rdev2
->flags
)) {
3532 s
->handle_bad_blocks
= 1;
3533 atomic_inc(&rdev2
->nr_pending
);
3535 clear_bit(R5_MadeGoodRepl
, &dev
->flags
);
3537 if (!test_bit(R5_Insync
, &dev
->flags
)) {
3538 /* The ReadError flag will just be confusing now */
3539 clear_bit(R5_ReadError
, &dev
->flags
);
3540 clear_bit(R5_ReWrite
, &dev
->flags
);
3542 if (test_bit(R5_ReadError
, &dev
->flags
))
3543 clear_bit(R5_Insync
, &dev
->flags
);
3544 if (!test_bit(R5_Insync
, &dev
->flags
)) {
3546 s
->failed_num
[s
->failed
] = i
;
3548 if (rdev
&& !test_bit(Faulty
, &rdev
->flags
))
3552 if (test_bit(STRIPE_SYNCING
, &sh
->state
)) {
3553 /* If there is a failed device being replaced,
3554 * we must be recovering.
3555 * else if we are after recovery_cp, we must be syncing
3556 * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
3557 * else we can only be replacing
3558 * sync and recovery both need to read all devices, and so
3559 * use the same flag.
3562 sh
->sector
>= conf
->mddev
->recovery_cp
||
3563 test_bit(MD_RECOVERY_REQUESTED
, &(conf
->mddev
->recovery
)))
3571 static void handle_stripe(struct stripe_head
*sh
)
3573 struct stripe_head_state s
;
3574 struct r5conf
*conf
= sh
->raid_conf
;
3577 int disks
= sh
->disks
;
3578 struct r5dev
*pdev
, *qdev
;
3580 clear_bit(STRIPE_HANDLE
, &sh
->state
);
3581 if (test_and_set_bit_lock(STRIPE_ACTIVE
, &sh
->state
)) {
3582 /* already being handled, ensure it gets handled
3583 * again when current action finishes */
3584 set_bit(STRIPE_HANDLE
, &sh
->state
);
3588 if (test_bit(STRIPE_SYNC_REQUESTED
, &sh
->state
)) {
3589 spin_lock(&sh
->stripe_lock
);
3590 /* Cannot process 'sync' concurrently with 'discard' */
3591 if (!test_bit(STRIPE_DISCARD
, &sh
->state
) &&
3592 test_and_clear_bit(STRIPE_SYNC_REQUESTED
, &sh
->state
)) {
3593 set_bit(STRIPE_SYNCING
, &sh
->state
);
3594 clear_bit(STRIPE_INSYNC
, &sh
->state
);
3595 clear_bit(STRIPE_REPLACED
, &sh
->state
);
3597 spin_unlock(&sh
->stripe_lock
);
3599 clear_bit(STRIPE_DELAYED
, &sh
->state
);
3601 pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
3602 "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
3603 (unsigned long long)sh
->sector
, sh
->state
,
3604 atomic_read(&sh
->count
), sh
->pd_idx
, sh
->qd_idx
,
3605 sh
->check_state
, sh
->reconstruct_state
);
3607 analyse_stripe(sh
, &s
);
3609 if (s
.handle_bad_blocks
) {
3610 set_bit(STRIPE_HANDLE
, &sh
->state
);
3614 if (unlikely(s
.blocked_rdev
)) {
3615 if (s
.syncing
|| s
.expanding
|| s
.expanded
||
3616 s
.replacing
|| s
.to_write
|| s
.written
) {
3617 set_bit(STRIPE_HANDLE
, &sh
->state
);
3620 /* There is nothing for the blocked_rdev to block */
3621 rdev_dec_pending(s
.blocked_rdev
, conf
->mddev
);
3622 s
.blocked_rdev
= NULL
;
3625 if (s
.to_fill
&& !test_bit(STRIPE_BIOFILL_RUN
, &sh
->state
)) {
3626 set_bit(STRIPE_OP_BIOFILL
, &s
.ops_request
);
3627 set_bit(STRIPE_BIOFILL_RUN
, &sh
->state
);
3630 pr_debug("locked=%d uptodate=%d to_read=%d"
3631 " to_write=%d failed=%d failed_num=%d,%d\n",
3632 s
.locked
, s
.uptodate
, s
.to_read
, s
.to_write
, s
.failed
,
3633 s
.failed_num
[0], s
.failed_num
[1]);
3634 /* check if the array has lost more than max_degraded devices and,
3635 * if so, some requests might need to be failed.
3637 if (s
.failed
> conf
->max_degraded
) {
3638 sh
->check_state
= 0;
3639 sh
->reconstruct_state
= 0;
3640 if (s
.to_read
+s
.to_write
+s
.written
)
3641 handle_failed_stripe(conf
, sh
, &s
, disks
, &s
.return_bi
);
3642 if (s
.syncing
+ s
.replacing
)
3643 handle_failed_sync(conf
, sh
, &s
);
3646 /* Now we check to see if any write operations have recently
3650 if (sh
->reconstruct_state
== reconstruct_state_prexor_drain_result
)
3652 if (sh
->reconstruct_state
== reconstruct_state_drain_result
||
3653 sh
->reconstruct_state
== reconstruct_state_prexor_drain_result
) {
3654 sh
->reconstruct_state
= reconstruct_state_idle
;
3656 /* All the 'written' buffers and the parity block are ready to
3657 * be written back to disk
3659 BUG_ON(!test_bit(R5_UPTODATE
, &sh
->dev
[sh
->pd_idx
].flags
) &&
3660 !test_bit(R5_Discard
, &sh
->dev
[sh
->pd_idx
].flags
));
3661 BUG_ON(sh
->qd_idx
>= 0 &&
3662 !test_bit(R5_UPTODATE
, &sh
->dev
[sh
->qd_idx
].flags
) &&
3663 !test_bit(R5_Discard
, &sh
->dev
[sh
->qd_idx
].flags
));
3664 for (i
= disks
; i
--; ) {
3665 struct r5dev
*dev
= &sh
->dev
[i
];
3666 if (test_bit(R5_LOCKED
, &dev
->flags
) &&
3667 (i
== sh
->pd_idx
|| i
== sh
->qd_idx
||
3669 pr_debug("Writing block %d\n", i
);
3670 set_bit(R5_Wantwrite
, &dev
->flags
);
3673 if (!test_bit(R5_Insync
, &dev
->flags
) ||
3674 ((i
== sh
->pd_idx
|| i
== sh
->qd_idx
) &&
3676 set_bit(STRIPE_INSYNC
, &sh
->state
);
3679 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE
, &sh
->state
))
3680 s
.dec_preread_active
= 1;
3684 * might be able to return some write requests if the parity blocks
3685 * are safe, or on a failed drive
3687 pdev
= &sh
->dev
[sh
->pd_idx
];
3688 s
.p_failed
= (s
.failed
>= 1 && s
.failed_num
[0] == sh
->pd_idx
)
3689 || (s
.failed
>= 2 && s
.failed_num
[1] == sh
->pd_idx
);
3690 qdev
= &sh
->dev
[sh
->qd_idx
];
3691 s
.q_failed
= (s
.failed
>= 1 && s
.failed_num
[0] == sh
->qd_idx
)
3692 || (s
.failed
>= 2 && s
.failed_num
[1] == sh
->qd_idx
)
3696 (s
.p_failed
|| ((test_bit(R5_Insync
, &pdev
->flags
)
3697 && !test_bit(R5_LOCKED
, &pdev
->flags
)
3698 && (test_bit(R5_UPTODATE
, &pdev
->flags
) ||
3699 test_bit(R5_Discard
, &pdev
->flags
))))) &&
3700 (s
.q_failed
|| ((test_bit(R5_Insync
, &qdev
->flags
)
3701 && !test_bit(R5_LOCKED
, &qdev
->flags
)
3702 && (test_bit(R5_UPTODATE
, &qdev
->flags
) ||
3703 test_bit(R5_Discard
, &qdev
->flags
))))))
3704 handle_stripe_clean_event(conf
, sh
, disks
, &s
.return_bi
);
3706 /* Now we might consider reading some blocks, either to check/generate
3707 * parity, or to satisfy requests
3708 * or to load a block that is being partially written.
3710 if (s
.to_read
|| s
.non_overwrite
3711 || (conf
->level
== 6 && s
.to_write
&& s
.failed
)
3712 || (s
.syncing
&& (s
.uptodate
+ s
.compute
< disks
))
3715 handle_stripe_fill(sh
, &s
, disks
);
3717 /* Now to consider new write requests and what else, if anything
3718 * should be read. We do not handle new writes when:
3719 * 1/ A 'write' operation (copy+xor) is already in flight.
3720 * 2/ A 'check' operation is in flight, as it may clobber the parity
3723 if (s
.to_write
&& !sh
->reconstruct_state
&& !sh
->check_state
)
3724 handle_stripe_dirtying(conf
, sh
, &s
, disks
);
3726 /* maybe we need to check and possibly fix the parity for this stripe
3727 * Any reads will already have been scheduled, so we just see if enough
3728 * data is available. The parity check is held off while parity
3729 * dependent operations are in flight.
3731 if (sh
->check_state
||
3732 (s
.syncing
&& s
.locked
== 0 &&
3733 !test_bit(STRIPE_COMPUTE_RUN
, &sh
->state
) &&
3734 !test_bit(STRIPE_INSYNC
, &sh
->state
))) {
3735 if (conf
->level
== 6)
3736 handle_parity_checks6(conf
, sh
, &s
, disks
);
3738 handle_parity_checks5(conf
, sh
, &s
, disks
);
3741 if ((s
.replacing
|| s
.syncing
) && s
.locked
== 0
3742 && !test_bit(STRIPE_COMPUTE_RUN
, &sh
->state
)
3743 && !test_bit(STRIPE_REPLACED
, &sh
->state
)) {
3744 /* Write out to replacement devices where possible */
3745 for (i
= 0; i
< conf
->raid_disks
; i
++)
3746 if (test_bit(R5_NeedReplace
, &sh
->dev
[i
].flags
)) {
3747 WARN_ON(!test_bit(R5_UPTODATE
, &sh
->dev
[i
].flags
));
3748 set_bit(R5_WantReplace
, &sh
->dev
[i
].flags
);
3749 set_bit(R5_LOCKED
, &sh
->dev
[i
].flags
);
3753 set_bit(STRIPE_INSYNC
, &sh
->state
);
3754 set_bit(STRIPE_REPLACED
, &sh
->state
);
3756 if ((s
.syncing
|| s
.replacing
) && s
.locked
== 0 &&
3757 !test_bit(STRIPE_COMPUTE_RUN
, &sh
->state
) &&
3758 test_bit(STRIPE_INSYNC
, &sh
->state
)) {
3759 md_done_sync(conf
->mddev
, STRIPE_SECTORS
, 1);
3760 clear_bit(STRIPE_SYNCING
, &sh
->state
);
3761 if (test_and_clear_bit(R5_Overlap
, &sh
->dev
[sh
->pd_idx
].flags
))
3762 wake_up(&conf
->wait_for_overlap
);
3765 /* If the failed drives are just a ReadError, then we might need
3766 * to progress the repair/check process
3768 if (s
.failed
<= conf
->max_degraded
&& !conf
->mddev
->ro
)
3769 for (i
= 0; i
< s
.failed
; i
++) {
3770 struct r5dev
*dev
= &sh
->dev
[s
.failed_num
[i
]];
3771 if (test_bit(R5_ReadError
, &dev
->flags
)
3772 && !test_bit(R5_LOCKED
, &dev
->flags
)
3773 && test_bit(R5_UPTODATE
, &dev
->flags
)
3775 if (!test_bit(R5_ReWrite
, &dev
->flags
)) {
3776 set_bit(R5_Wantwrite
, &dev
->flags
);
3777 set_bit(R5_ReWrite
, &dev
->flags
);
3778 set_bit(R5_LOCKED
, &dev
->flags
);
3781 /* let's read it back */
3782 set_bit(R5_Wantread
, &dev
->flags
);
3783 set_bit(R5_LOCKED
, &dev
->flags
);
3790 /* Finish reconstruct operations initiated by the expansion process */
3791 if (sh
->reconstruct_state
== reconstruct_state_result
) {
3792 struct stripe_head
*sh_src
3793 = get_active_stripe(conf
, sh
->sector
, 1, 1, 1);
3794 if (sh_src
&& test_bit(STRIPE_EXPAND_SOURCE
, &sh_src
->state
)) {
3795 /* sh cannot be written until sh_src has been read.
3796 * so arrange for sh to be delayed a little
3798 set_bit(STRIPE_DELAYED
, &sh
->state
);
3799 set_bit(STRIPE_HANDLE
, &sh
->state
);
3800 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE
,
3802 atomic_inc(&conf
->preread_active_stripes
);
3803 release_stripe(sh_src
);
3807 release_stripe(sh_src
);
3809 sh
->reconstruct_state
= reconstruct_state_idle
;
3810 clear_bit(STRIPE_EXPANDING
, &sh
->state
);
3811 for (i
= conf
->raid_disks
; i
--; ) {
3812 set_bit(R5_Wantwrite
, &sh
->dev
[i
].flags
);
3813 set_bit(R5_LOCKED
, &sh
->dev
[i
].flags
);
3818 if (s
.expanded
&& test_bit(STRIPE_EXPANDING
, &sh
->state
) &&
3819 !sh
->reconstruct_state
) {
3820 /* Need to write out all blocks after computing parity */
3821 sh
->disks
= conf
->raid_disks
;
3822 stripe_set_idx(sh
->sector
, conf
, 0, sh
);
3823 schedule_reconstruction(sh
, &s
, 1, 1);
3824 } else if (s
.expanded
&& !sh
->reconstruct_state
&& s
.locked
== 0) {
3825 clear_bit(STRIPE_EXPAND_READY
, &sh
->state
);
3826 atomic_dec(&conf
->reshape_stripes
);
3827 wake_up(&conf
->wait_for_overlap
);
3828 md_done_sync(conf
->mddev
, STRIPE_SECTORS
, 1);
3831 if (s
.expanding
&& s
.locked
== 0 &&
3832 !test_bit(STRIPE_COMPUTE_RUN
, &sh
->state
))
3833 handle_stripe_expansion(conf
, sh
);
3836 /* wait for this device to become unblocked */
3837 if (unlikely(s
.blocked_rdev
)) {
3838 if (conf
->mddev
->external
)
3839 md_wait_for_blocked_rdev(s
.blocked_rdev
,
3842 /* Internal metadata will immediately
3843 * be written by raid5d, so we don't
3844 * need to wait here.
3846 rdev_dec_pending(s
.blocked_rdev
,
3850 if (s
.handle_bad_blocks
)
3851 for (i
= disks
; i
--; ) {
3852 struct md_rdev
*rdev
;
3853 struct r5dev
*dev
= &sh
->dev
[i
];
3854 if (test_and_clear_bit(R5_WriteError
, &dev
->flags
)) {
3855 /* We own a safe reference to the rdev */
3856 rdev
= conf
->disks
[i
].rdev
;
3857 if (!rdev_set_badblocks(rdev
, sh
->sector
,
3859 md_error(conf
->mddev
, rdev
);
3860 rdev_dec_pending(rdev
, conf
->mddev
);
3862 if (test_and_clear_bit(R5_MadeGood
, &dev
->flags
)) {
3863 rdev
= conf
->disks
[i
].rdev
;
3864 rdev_clear_badblocks(rdev
, sh
->sector
,
3866 rdev_dec_pending(rdev
, conf
->mddev
);
3868 if (test_and_clear_bit(R5_MadeGoodRepl
, &dev
->flags
)) {
3869 rdev
= conf
->disks
[i
].replacement
;
3871 /* rdev have been moved down */
3872 rdev
= conf
->disks
[i
].rdev
;
3873 rdev_clear_badblocks(rdev
, sh
->sector
,
3875 rdev_dec_pending(rdev
, conf
->mddev
);
3880 raid_run_ops(sh
, s
.ops_request
);
3884 if (s
.dec_preread_active
) {
3885 /* We delay this until after ops_run_io so that if make_request
3886 * is waiting on a flush, it won't continue until the writes
3887 * have actually been submitted.
3889 atomic_dec(&conf
->preread_active_stripes
);
3890 if (atomic_read(&conf
->preread_active_stripes
) <
3892 md_wakeup_thread(conf
->mddev
->thread
);
3895 return_io(s
.return_bi
);
3897 clear_bit_unlock(STRIPE_ACTIVE
, &sh
->state
);
3900 static void raid5_activate_delayed(struct r5conf
*conf
)
3902 if (atomic_read(&conf
->preread_active_stripes
) < IO_THRESHOLD
) {
3903 while (!list_empty(&conf
->delayed_list
)) {
3904 struct list_head
*l
= conf
->delayed_list
.next
;
3905 struct stripe_head
*sh
;
3906 sh
= list_entry(l
, struct stripe_head
, lru
);
3908 clear_bit(STRIPE_DELAYED
, &sh
->state
);
3909 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE
, &sh
->state
))
3910 atomic_inc(&conf
->preread_active_stripes
);
3911 list_add_tail(&sh
->lru
, &conf
->hold_list
);
3912 raid5_wakeup_stripe_thread(sh
);
3917 static void activate_bit_delay(struct r5conf
*conf
)
3919 /* device_lock is held */
3920 struct list_head head
;
3921 list_add(&head
, &conf
->bitmap_list
);
3922 list_del_init(&conf
->bitmap_list
);
3923 while (!list_empty(&head
)) {
3924 struct stripe_head
*sh
= list_entry(head
.next
, struct stripe_head
, lru
);
3925 list_del_init(&sh
->lru
);
3926 atomic_inc(&sh
->count
);
3927 __release_stripe(conf
, sh
);
3931 int md_raid5_congested(struct mddev
*mddev
, int bits
)
3933 struct r5conf
*conf
= mddev
->private;
3935 /* No difference between reads and writes. Just check
3936 * how busy the stripe_cache is
3939 if (conf
->inactive_blocked
)
3943 if (list_empty_careful(&conf
->inactive_list
))
3948 EXPORT_SYMBOL_GPL(md_raid5_congested
);
3950 static int raid5_congested(void *data
, int bits
)
3952 struct mddev
*mddev
= data
;
3954 return mddev_congested(mddev
, bits
) ||
3955 md_raid5_congested(mddev
, bits
);
3958 /* We want read requests to align with chunks where possible,
3959 * but write requests don't need to.
3961 static int raid5_mergeable_bvec(struct request_queue
*q
,
3962 struct bvec_merge_data
*bvm
,
3963 struct bio_vec
*biovec
)
3965 struct mddev
*mddev
= q
->queuedata
;
3966 sector_t sector
= bvm
->bi_sector
+ get_start_sect(bvm
->bi_bdev
);
3968 unsigned int chunk_sectors
= mddev
->chunk_sectors
;
3969 unsigned int bio_sectors
= bvm
->bi_size
>> 9;
3971 if ((bvm
->bi_rw
& 1) == WRITE
)
3972 return biovec
->bv_len
; /* always allow writes to be mergeable */
3974 if (mddev
->new_chunk_sectors
< mddev
->chunk_sectors
)
3975 chunk_sectors
= mddev
->new_chunk_sectors
;
3976 max
= (chunk_sectors
- ((sector
& (chunk_sectors
- 1)) + bio_sectors
)) << 9;
3977 if (max
< 0) max
= 0;
3978 if (max
<= biovec
->bv_len
&& bio_sectors
== 0)
3979 return biovec
->bv_len
;
3985 static int in_chunk_boundary(struct mddev
*mddev
, struct bio
*bio
)
3987 sector_t sector
= bio
->bi_sector
+ get_start_sect(bio
->bi_bdev
);
3988 unsigned int chunk_sectors
= mddev
->chunk_sectors
;
3989 unsigned int bio_sectors
= bio_sectors(bio
);
3991 if (mddev
->new_chunk_sectors
< mddev
->chunk_sectors
)
3992 chunk_sectors
= mddev
->new_chunk_sectors
;
3993 return chunk_sectors
>=
3994 ((sector
& (chunk_sectors
- 1)) + bio_sectors
);
3998 * add bio to the retry LIFO ( in O(1) ... we are in interrupt )
3999 * later sampled by raid5d.
4001 static void add_bio_to_retry(struct bio
*bi
,struct r5conf
*conf
)
4003 unsigned long flags
;
4005 spin_lock_irqsave(&conf
->device_lock
, flags
);
4007 bi
->bi_next
= conf
->retry_read_aligned_list
;
4008 conf
->retry_read_aligned_list
= bi
;
4010 spin_unlock_irqrestore(&conf
->device_lock
, flags
);
4011 md_wakeup_thread(conf
->mddev
->thread
);
4015 static struct bio
*remove_bio_from_retry(struct r5conf
*conf
)
4019 bi
= conf
->retry_read_aligned
;
4021 conf
->retry_read_aligned
= NULL
;
4024 bi
= conf
->retry_read_aligned_list
;
4026 conf
->retry_read_aligned_list
= bi
->bi_next
;
4029 * this sets the active strip count to 1 and the processed
4030 * strip count to zero (upper 8 bits)
4032 raid5_set_bi_stripes(bi
, 1); /* biased count of active stripes */
4040 * The "raid5_align_endio" should check if the read succeeded and if it
4041 * did, call bio_endio on the original bio (having bio_put the new bio
4043 * If the read failed..
4045 static void raid5_align_endio(struct bio
*bi
, int error
)
4047 struct bio
* raid_bi
= bi
->bi_private
;
4048 struct mddev
*mddev
;
4049 struct r5conf
*conf
;
4050 int uptodate
= test_bit(BIO_UPTODATE
, &bi
->bi_flags
);
4051 struct md_rdev
*rdev
;
4055 rdev
= (void*)raid_bi
->bi_next
;
4056 raid_bi
->bi_next
= NULL
;
4057 mddev
= rdev
->mddev
;
4058 conf
= mddev
->private;
4060 rdev_dec_pending(rdev
, conf
->mddev
);
4062 if (!error
&& uptodate
) {
4063 trace_block_bio_complete(bdev_get_queue(raid_bi
->bi_bdev
),
4065 bio_endio(raid_bi
, 0);
4066 if (atomic_dec_and_test(&conf
->active_aligned_reads
))
4067 wake_up(&conf
->wait_for_stripe
);
4072 pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
4074 add_bio_to_retry(raid_bi
, conf
);
4077 static int bio_fits_rdev(struct bio
*bi
)
4079 struct request_queue
*q
= bdev_get_queue(bi
->bi_bdev
);
4081 if (bio_sectors(bi
) > queue_max_sectors(q
))
4083 blk_recount_segments(q
, bi
);
4084 if (bi
->bi_phys_segments
> queue_max_segments(q
))
4087 if (q
->merge_bvec_fn
)
4088 /* it's too hard to apply the merge_bvec_fn at this stage,
4097 static int chunk_aligned_read(struct mddev
*mddev
, struct bio
* raid_bio
)
4099 struct r5conf
*conf
= mddev
->private;
4101 struct bio
* align_bi
;
4102 struct md_rdev
*rdev
;
4103 sector_t end_sector
;
4105 if (!in_chunk_boundary(mddev
, raid_bio
)) {
4106 pr_debug("chunk_aligned_read : non aligned\n");
4110 * use bio_clone_mddev to make a copy of the bio
4112 align_bi
= bio_clone_mddev(raid_bio
, GFP_NOIO
, mddev
);
4116 * set bi_end_io to a new function, and set bi_private to the
4119 align_bi
->bi_end_io
= raid5_align_endio
;
4120 align_bi
->bi_private
= raid_bio
;
4124 align_bi
->bi_sector
= raid5_compute_sector(conf
, raid_bio
->bi_sector
,
4128 end_sector
= bio_end_sector(align_bi
);
4130 rdev
= rcu_dereference(conf
->disks
[dd_idx
].replacement
);
4131 if (!rdev
|| test_bit(Faulty
, &rdev
->flags
) ||
4132 rdev
->recovery_offset
< end_sector
) {
4133 rdev
= rcu_dereference(conf
->disks
[dd_idx
].rdev
);
4135 (test_bit(Faulty
, &rdev
->flags
) ||
4136 !(test_bit(In_sync
, &rdev
->flags
) ||
4137 rdev
->recovery_offset
>= end_sector
)))
4144 atomic_inc(&rdev
->nr_pending
);
4146 raid_bio
->bi_next
= (void*)rdev
;
4147 align_bi
->bi_bdev
= rdev
->bdev
;
4148 align_bi
->bi_flags
&= ~(1 << BIO_SEG_VALID
);
4150 if (!bio_fits_rdev(align_bi
) ||
4151 is_badblock(rdev
, align_bi
->bi_sector
, bio_sectors(align_bi
),
4152 &first_bad
, &bad_sectors
)) {
4153 /* too big in some way, or has a known bad block */
4155 rdev_dec_pending(rdev
, mddev
);
4159 /* No reshape active, so we can trust rdev->data_offset */
4160 align_bi
->bi_sector
+= rdev
->data_offset
;
4162 spin_lock_irq(&conf
->device_lock
);
4163 wait_event_lock_irq(conf
->wait_for_stripe
,
4166 atomic_inc(&conf
->active_aligned_reads
);
4167 spin_unlock_irq(&conf
->device_lock
);
4170 trace_block_bio_remap(bdev_get_queue(align_bi
->bi_bdev
),
4171 align_bi
, disk_devt(mddev
->gendisk
),
4172 raid_bio
->bi_sector
);
4173 generic_make_request(align_bi
);
4182 /* __get_priority_stripe - get the next stripe to process
4184 * Full stripe writes are allowed to pass preread active stripes up until
4185 * the bypass_threshold is exceeded. In general the bypass_count
4186 * increments when the handle_list is handled before the hold_list; however, it
4187 * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
4188 * stripe with in flight i/o. The bypass_count will be reset when the
4189 * head of the hold_list has changed, i.e. the head was promoted to the
4192 static struct stripe_head
*__get_priority_stripe(struct r5conf
*conf
, int group
)
4194 struct stripe_head
*sh
= NULL
, *tmp
;
4195 struct list_head
*handle_list
= NULL
;
4196 struct r5worker_group
*wg
= NULL
;
4198 if (conf
->worker_cnt_per_group
== 0) {
4199 handle_list
= &conf
->handle_list
;
4200 } else if (group
!= ANY_GROUP
) {
4201 handle_list
= &conf
->worker_groups
[group
].handle_list
;
4202 wg
= &conf
->worker_groups
[group
];
4205 for (i
= 0; i
< conf
->group_cnt
; i
++) {
4206 handle_list
= &conf
->worker_groups
[i
].handle_list
;
4207 wg
= &conf
->worker_groups
[i
];
4208 if (!list_empty(handle_list
))
4213 pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
4215 list_empty(handle_list
) ? "empty" : "busy",
4216 list_empty(&conf
->hold_list
) ? "empty" : "busy",
4217 atomic_read(&conf
->pending_full_writes
), conf
->bypass_count
);
4219 if (!list_empty(handle_list
)) {
4220 sh
= list_entry(handle_list
->next
, typeof(*sh
), lru
);
4222 if (list_empty(&conf
->hold_list
))
4223 conf
->bypass_count
= 0;
4224 else if (!test_bit(STRIPE_IO_STARTED
, &sh
->state
)) {
4225 if (conf
->hold_list
.next
== conf
->last_hold
)
4226 conf
->bypass_count
++;
4228 conf
->last_hold
= conf
->hold_list
.next
;
4229 conf
->bypass_count
-= conf
->bypass_threshold
;
4230 if (conf
->bypass_count
< 0)
4231 conf
->bypass_count
= 0;
4234 } else if (!list_empty(&conf
->hold_list
) &&
4235 ((conf
->bypass_threshold
&&
4236 conf
->bypass_count
> conf
->bypass_threshold
) ||
4237 atomic_read(&conf
->pending_full_writes
) == 0)) {
4239 list_for_each_entry(tmp
, &conf
->hold_list
, lru
) {
4240 if (conf
->worker_cnt_per_group
== 0 ||
4241 group
== ANY_GROUP
||
4242 !cpu_online(tmp
->cpu
) ||
4243 cpu_to_group(tmp
->cpu
) == group
) {
4250 conf
->bypass_count
-= conf
->bypass_threshold
;
4251 if (conf
->bypass_count
< 0)
4252 conf
->bypass_count
= 0;
4264 list_del_init(&sh
->lru
);
4265 atomic_inc(&sh
->count
);
4266 BUG_ON(atomic_read(&sh
->count
) != 1);
4270 struct raid5_plug_cb
{
4271 struct blk_plug_cb cb
;
4272 struct list_head list
;
4275 static void raid5_unplug(struct blk_plug_cb
*blk_cb
, bool from_schedule
)
4277 struct raid5_plug_cb
*cb
= container_of(
4278 blk_cb
, struct raid5_plug_cb
, cb
);
4279 struct stripe_head
*sh
;
4280 struct mddev
*mddev
= cb
->cb
.data
;
4281 struct r5conf
*conf
= mddev
->private;
4284 if (cb
->list
.next
&& !list_empty(&cb
->list
)) {
4285 spin_lock_irq(&conf
->device_lock
);
4286 while (!list_empty(&cb
->list
)) {
4287 sh
= list_first_entry(&cb
->list
, struct stripe_head
, lru
);
4288 list_del_init(&sh
->lru
);
4290 * avoid race release_stripe_plug() sees
4291 * STRIPE_ON_UNPLUG_LIST clear but the stripe
4292 * is still in our list
4294 smp_mb__before_clear_bit();
4295 clear_bit(STRIPE_ON_UNPLUG_LIST
, &sh
->state
);
4297 * STRIPE_ON_RELEASE_LIST could be set here. In that
4298 * case, the count is always > 1 here
4300 __release_stripe(conf
, sh
);
4303 spin_unlock_irq(&conf
->device_lock
);
4306 trace_block_unplug(mddev
->queue
, cnt
, !from_schedule
);
4310 static void release_stripe_plug(struct mddev
*mddev
,
4311 struct stripe_head
*sh
)
4313 struct blk_plug_cb
*blk_cb
= blk_check_plugged(
4314 raid5_unplug
, mddev
,
4315 sizeof(struct raid5_plug_cb
));
4316 struct raid5_plug_cb
*cb
;
4323 cb
= container_of(blk_cb
, struct raid5_plug_cb
, cb
);
4325 if (cb
->list
.next
== NULL
)
4326 INIT_LIST_HEAD(&cb
->list
);
4328 if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST
, &sh
->state
))
4329 list_add_tail(&sh
->lru
, &cb
->list
);
4334 static void make_discard_request(struct mddev
*mddev
, struct bio
*bi
)
4336 struct r5conf
*conf
= mddev
->private;
4337 sector_t logical_sector
, last_sector
;
4338 struct stripe_head
*sh
;
4342 if (mddev
->reshape_position
!= MaxSector
)
4343 /* Skip discard while reshape is happening */
4346 logical_sector
= bi
->bi_sector
& ~((sector_t
)STRIPE_SECTORS
-1);
4347 last_sector
= bi
->bi_sector
+ (bi
->bi_size
>>9);
4350 bi
->bi_phys_segments
= 1; /* over-loaded to count active stripes */
4352 stripe_sectors
= conf
->chunk_sectors
*
4353 (conf
->raid_disks
- conf
->max_degraded
);
4354 logical_sector
= DIV_ROUND_UP_SECTOR_T(logical_sector
,
4356 sector_div(last_sector
, stripe_sectors
);
4358 logical_sector
*= conf
->chunk_sectors
;
4359 last_sector
*= conf
->chunk_sectors
;
4361 for (; logical_sector
< last_sector
;
4362 logical_sector
+= STRIPE_SECTORS
) {
4366 sh
= get_active_stripe(conf
, logical_sector
, 0, 0, 0);
4367 prepare_to_wait(&conf
->wait_for_overlap
, &w
,
4368 TASK_UNINTERRUPTIBLE
);
4369 set_bit(R5_Overlap
, &sh
->dev
[sh
->pd_idx
].flags
);
4370 if (test_bit(STRIPE_SYNCING
, &sh
->state
)) {
4375 clear_bit(R5_Overlap
, &sh
->dev
[sh
->pd_idx
].flags
);
4376 spin_lock_irq(&sh
->stripe_lock
);
4377 for (d
= 0; d
< conf
->raid_disks
; d
++) {
4378 if (d
== sh
->pd_idx
|| d
== sh
->qd_idx
)
4380 if (sh
->dev
[d
].towrite
|| sh
->dev
[d
].toread
) {
4381 set_bit(R5_Overlap
, &sh
->dev
[d
].flags
);
4382 spin_unlock_irq(&sh
->stripe_lock
);
4388 set_bit(STRIPE_DISCARD
, &sh
->state
);
4389 finish_wait(&conf
->wait_for_overlap
, &w
);
4390 for (d
= 0; d
< conf
->raid_disks
; d
++) {
4391 if (d
== sh
->pd_idx
|| d
== sh
->qd_idx
)
4393 sh
->dev
[d
].towrite
= bi
;
4394 set_bit(R5_OVERWRITE
, &sh
->dev
[d
].flags
);
4395 raid5_inc_bi_active_stripes(bi
);
4397 spin_unlock_irq(&sh
->stripe_lock
);
4398 if (conf
->mddev
->bitmap
) {
4400 d
< conf
->raid_disks
- conf
->max_degraded
;
4402 bitmap_startwrite(mddev
->bitmap
,
4406 sh
->bm_seq
= conf
->seq_flush
+ 1;
4407 set_bit(STRIPE_BIT_DELAY
, &sh
->state
);
4410 set_bit(STRIPE_HANDLE
, &sh
->state
);
4411 clear_bit(STRIPE_DELAYED
, &sh
->state
);
4412 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE
, &sh
->state
))
4413 atomic_inc(&conf
->preread_active_stripes
);
4414 release_stripe_plug(mddev
, sh
);
4417 remaining
= raid5_dec_bi_active_stripes(bi
);
4418 if (remaining
== 0) {
4419 md_write_end(mddev
);
4424 static void make_request(struct mddev
*mddev
, struct bio
* bi
)
4426 struct r5conf
*conf
= mddev
->private;
4428 sector_t new_sector
;
4429 sector_t logical_sector
, last_sector
;
4430 struct stripe_head
*sh
;
4431 const int rw
= bio_data_dir(bi
);
4434 if (unlikely(bi
->bi_rw
& REQ_FLUSH
)) {
4435 md_flush_request(mddev
, bi
);
4439 md_write_start(mddev
, bi
);
4442 mddev
->reshape_position
== MaxSector
&&
4443 chunk_aligned_read(mddev
,bi
))
4446 if (unlikely(bi
->bi_rw
& REQ_DISCARD
)) {
4447 make_discard_request(mddev
, bi
);
4451 logical_sector
= bi
->bi_sector
& ~((sector_t
)STRIPE_SECTORS
-1);
4452 last_sector
= bio_end_sector(bi
);
4454 bi
->bi_phys_segments
= 1; /* over-loaded to count active stripes */
4456 for (;logical_sector
< last_sector
; logical_sector
+= STRIPE_SECTORS
) {
4462 seq
= read_seqcount_begin(&conf
->gen_lock
);
4464 prepare_to_wait(&conf
->wait_for_overlap
, &w
, TASK_UNINTERRUPTIBLE
);
4465 if (unlikely(conf
->reshape_progress
!= MaxSector
)) {
4466 /* spinlock is needed as reshape_progress may be
4467 * 64bit on a 32bit platform, and so it might be
4468 * possible to see a half-updated value
4469 * Of course reshape_progress could change after
4470 * the lock is dropped, so once we get a reference
4471 * to the stripe that we think it is, we will have
4474 spin_lock_irq(&conf
->device_lock
);
4475 if (mddev
->reshape_backwards
4476 ? logical_sector
< conf
->reshape_progress
4477 : logical_sector
>= conf
->reshape_progress
) {
4480 if (mddev
->reshape_backwards
4481 ? logical_sector
< conf
->reshape_safe
4482 : logical_sector
>= conf
->reshape_safe
) {
4483 spin_unlock_irq(&conf
->device_lock
);
4488 spin_unlock_irq(&conf
->device_lock
);
4491 new_sector
= raid5_compute_sector(conf
, logical_sector
,
4494 pr_debug("raid456: make_request, sector %llu logical %llu\n",
4495 (unsigned long long)new_sector
,
4496 (unsigned long long)logical_sector
);
4498 sh
= get_active_stripe(conf
, new_sector
, previous
,
4499 (bi
->bi_rw
&RWA_MASK
), 0);
4501 if (unlikely(previous
)) {
4502 /* expansion might have moved on while waiting for a
4503 * stripe, so we must do the range check again.
4504 * Expansion could still move past after this
4505 * test, but as we are holding a reference to
4506 * 'sh', we know that if that happens,
4507 * STRIPE_EXPANDING will get set and the expansion
4508 * won't proceed until we finish with the stripe.
4511 spin_lock_irq(&conf
->device_lock
);
4512 if (mddev
->reshape_backwards
4513 ? logical_sector
>= conf
->reshape_progress
4514 : logical_sector
< conf
->reshape_progress
)
4515 /* mismatch, need to try again */
4517 spin_unlock_irq(&conf
->device_lock
);
4524 if (read_seqcount_retry(&conf
->gen_lock
, seq
)) {
4525 /* Might have got the wrong stripe_head
4533 logical_sector
>= mddev
->suspend_lo
&&
4534 logical_sector
< mddev
->suspend_hi
) {
4536 /* As the suspend_* range is controlled by
4537 * userspace, we want an interruptible
4540 flush_signals(current
);
4541 prepare_to_wait(&conf
->wait_for_overlap
,
4542 &w
, TASK_INTERRUPTIBLE
);
4543 if (logical_sector
>= mddev
->suspend_lo
&&
4544 logical_sector
< mddev
->suspend_hi
)
4549 if (test_bit(STRIPE_EXPANDING
, &sh
->state
) ||
4550 !add_stripe_bio(sh
, bi
, dd_idx
, rw
)) {
4551 /* Stripe is busy expanding or
4552 * add failed due to overlap. Flush everything
4555 md_wakeup_thread(mddev
->thread
);
4560 finish_wait(&conf
->wait_for_overlap
, &w
);
4561 set_bit(STRIPE_HANDLE
, &sh
->state
);
4562 clear_bit(STRIPE_DELAYED
, &sh
->state
);
4563 if ((bi
->bi_rw
& REQ_SYNC
) &&
4564 !test_and_set_bit(STRIPE_PREREAD_ACTIVE
, &sh
->state
))
4565 atomic_inc(&conf
->preread_active_stripes
);
4566 release_stripe_plug(mddev
, sh
);
4568 /* cannot get stripe for read-ahead, just give-up */
4569 clear_bit(BIO_UPTODATE
, &bi
->bi_flags
);
4570 finish_wait(&conf
->wait_for_overlap
, &w
);
4575 remaining
= raid5_dec_bi_active_stripes(bi
);
4576 if (remaining
== 0) {
4579 md_write_end(mddev
);
4581 trace_block_bio_complete(bdev_get_queue(bi
->bi_bdev
),
4587 static sector_t
raid5_size(struct mddev
*mddev
, sector_t sectors
, int raid_disks
);
4589 static sector_t
reshape_request(struct mddev
*mddev
, sector_t sector_nr
, int *skipped
)
4591 /* reshaping is quite different to recovery/resync so it is
4592 * handled quite separately ... here.
4594 * On each call to sync_request, we gather one chunk worth of
4595 * destination stripes and flag them as expanding.
4596 * Then we find all the source stripes and request reads.
4597 * As the reads complete, handle_stripe will copy the data
4598 * into the destination stripe and release that stripe.
4600 struct r5conf
*conf
= mddev
->private;
4601 struct stripe_head
*sh
;
4602 sector_t first_sector
, last_sector
;
4603 int raid_disks
= conf
->previous_raid_disks
;
4604 int data_disks
= raid_disks
- conf
->max_degraded
;
4605 int new_data_disks
= conf
->raid_disks
- conf
->max_degraded
;
4608 sector_t writepos
, readpos
, safepos
;
4609 sector_t stripe_addr
;
4610 int reshape_sectors
;
4611 struct list_head stripes
;
4613 if (sector_nr
== 0) {
4614 /* If restarting in the middle, skip the initial sectors */
4615 if (mddev
->reshape_backwards
&&
4616 conf
->reshape_progress
< raid5_size(mddev
, 0, 0)) {
4617 sector_nr
= raid5_size(mddev
, 0, 0)
4618 - conf
->reshape_progress
;
4619 } else if (!mddev
->reshape_backwards
&&
4620 conf
->reshape_progress
> 0)
4621 sector_nr
= conf
->reshape_progress
;
4622 sector_div(sector_nr
, new_data_disks
);
4624 mddev
->curr_resync_completed
= sector_nr
;
4625 sysfs_notify(&mddev
->kobj
, NULL
, "sync_completed");
4631 /* We need to process a full chunk at a time.
4632 * If old and new chunk sizes differ, we need to process the
4635 if (mddev
->new_chunk_sectors
> mddev
->chunk_sectors
)
4636 reshape_sectors
= mddev
->new_chunk_sectors
;
4638 reshape_sectors
= mddev
->chunk_sectors
;
4640 /* We update the metadata at least every 10 seconds, or when
4641 * the data about to be copied would over-write the source of
4642 * the data at the front of the range. i.e. one new_stripe
4643 * along from reshape_progress new_maps to after where
4644 * reshape_safe old_maps to
4646 writepos
= conf
->reshape_progress
;
4647 sector_div(writepos
, new_data_disks
);
4648 readpos
= conf
->reshape_progress
;
4649 sector_div(readpos
, data_disks
);
4650 safepos
= conf
->reshape_safe
;
4651 sector_div(safepos
, data_disks
);
4652 if (mddev
->reshape_backwards
) {
4653 writepos
-= min_t(sector_t
, reshape_sectors
, writepos
);
4654 readpos
+= reshape_sectors
;
4655 safepos
+= reshape_sectors
;
4657 writepos
+= reshape_sectors
;
4658 readpos
-= min_t(sector_t
, reshape_sectors
, readpos
);
4659 safepos
-= min_t(sector_t
, reshape_sectors
, safepos
);
4662 /* Having calculated the 'writepos' possibly use it
4663 * to set 'stripe_addr' which is where we will write to.
4665 if (mddev
->reshape_backwards
) {
4666 BUG_ON(conf
->reshape_progress
== 0);
4667 stripe_addr
= writepos
;
4668 BUG_ON((mddev
->dev_sectors
&
4669 ~((sector_t
)reshape_sectors
- 1))
4670 - reshape_sectors
- stripe_addr
4673 BUG_ON(writepos
!= sector_nr
+ reshape_sectors
);
4674 stripe_addr
= sector_nr
;
4677 /* 'writepos' is the most advanced device address we might write.
4678 * 'readpos' is the least advanced device address we might read.
4679 * 'safepos' is the least address recorded in the metadata as having
4681 * If there is a min_offset_diff, these are adjusted either by
4682 * increasing the safepos/readpos if diff is negative, or
4683 * increasing writepos if diff is positive.
4684 * If 'readpos' is then behind 'writepos', there is no way that we can
4685 * ensure safety in the face of a crash - that must be done by userspace
4686 * making a backup of the data. So in that case there is no particular
4687 * rush to update metadata.
4688 * Otherwise if 'safepos' is behind 'writepos', then we really need to
4689 * update the metadata to advance 'safepos' to match 'readpos' so that
4690 * we can be safe in the event of a crash.
4691 * So we insist on updating metadata if safepos is behind writepos and
4692 * readpos is beyond writepos.
4693 * In any case, update the metadata every 10 seconds.
4694 * Maybe that number should be configurable, but I'm not sure it is
4695 * worth it.... maybe it could be a multiple of safemode_delay???
4697 if (conf
->min_offset_diff
< 0) {
4698 safepos
+= -conf
->min_offset_diff
;
4699 readpos
+= -conf
->min_offset_diff
;
4701 writepos
+= conf
->min_offset_diff
;
4703 if ((mddev
->reshape_backwards
4704 ? (safepos
> writepos
&& readpos
< writepos
)
4705 : (safepos
< writepos
&& readpos
> writepos
)) ||
4706 time_after(jiffies
, conf
->reshape_checkpoint
+ 10*HZ
)) {
4707 /* Cannot proceed until we've updated the superblock... */
4708 wait_event(conf
->wait_for_overlap
,
4709 atomic_read(&conf
->reshape_stripes
)==0);
4710 mddev
->reshape_position
= conf
->reshape_progress
;
4711 mddev
->curr_resync_completed
= sector_nr
;
4712 conf
->reshape_checkpoint
= jiffies
;
4713 set_bit(MD_CHANGE_DEVS
, &mddev
->flags
);
4714 md_wakeup_thread(mddev
->thread
);
4715 wait_event(mddev
->sb_wait
, mddev
->flags
== 0 ||
4716 kthread_should_stop());
4717 spin_lock_irq(&conf
->device_lock
);
4718 conf
->reshape_safe
= mddev
->reshape_position
;
4719 spin_unlock_irq(&conf
->device_lock
);
4720 wake_up(&conf
->wait_for_overlap
);
4721 sysfs_notify(&mddev
->kobj
, NULL
, "sync_completed");
4724 INIT_LIST_HEAD(&stripes
);
4725 for (i
= 0; i
< reshape_sectors
; i
+= STRIPE_SECTORS
) {
4727 int skipped_disk
= 0;
4728 sh
= get_active_stripe(conf
, stripe_addr
+i
, 0, 0, 1);
4729 set_bit(STRIPE_EXPANDING
, &sh
->state
);
4730 atomic_inc(&conf
->reshape_stripes
);
4731 /* If any of this stripe is beyond the end of the old
4732 * array, then we need to zero those blocks
4734 for (j
=sh
->disks
; j
--;) {
4736 if (j
== sh
->pd_idx
)
4738 if (conf
->level
== 6 &&
4741 s
= compute_blocknr(sh
, j
, 0);
4742 if (s
< raid5_size(mddev
, 0, 0)) {
4746 memset(page_address(sh
->dev
[j
].page
), 0, STRIPE_SIZE
);
4747 set_bit(R5_Expanded
, &sh
->dev
[j
].flags
);
4748 set_bit(R5_UPTODATE
, &sh
->dev
[j
].flags
);
4750 if (!skipped_disk
) {
4751 set_bit(STRIPE_EXPAND_READY
, &sh
->state
);
4752 set_bit(STRIPE_HANDLE
, &sh
->state
);
4754 list_add(&sh
->lru
, &stripes
);
4756 spin_lock_irq(&conf
->device_lock
);
4757 if (mddev
->reshape_backwards
)
4758 conf
->reshape_progress
-= reshape_sectors
* new_data_disks
;
4760 conf
->reshape_progress
+= reshape_sectors
* new_data_disks
;
4761 spin_unlock_irq(&conf
->device_lock
);
4762 /* Ok, those stripe are ready. We can start scheduling
4763 * reads on the source stripes.
4764 * The source stripes are determined by mapping the first and last
4765 * block on the destination stripes.
4768 raid5_compute_sector(conf
, stripe_addr
*(new_data_disks
),
4771 raid5_compute_sector(conf
, ((stripe_addr
+reshape_sectors
)
4772 * new_data_disks
- 1),
4774 if (last_sector
>= mddev
->dev_sectors
)
4775 last_sector
= mddev
->dev_sectors
- 1;
4776 while (first_sector
<= last_sector
) {
4777 sh
= get_active_stripe(conf
, first_sector
, 1, 0, 1);
4778 set_bit(STRIPE_EXPAND_SOURCE
, &sh
->state
);
4779 set_bit(STRIPE_HANDLE
, &sh
->state
);
4781 first_sector
+= STRIPE_SECTORS
;
4783 /* Now that the sources are clearly marked, we can release
4784 * the destination stripes
4786 while (!list_empty(&stripes
)) {
4787 sh
= list_entry(stripes
.next
, struct stripe_head
, lru
);
4788 list_del_init(&sh
->lru
);
4791 /* If this takes us to the resync_max point where we have to pause,
4792 * then we need to write out the superblock.
4794 sector_nr
+= reshape_sectors
;
4795 if ((sector_nr
- mddev
->curr_resync_completed
) * 2
4796 >= mddev
->resync_max
- mddev
->curr_resync_completed
) {
4797 /* Cannot proceed until we've updated the superblock... */
4798 wait_event(conf
->wait_for_overlap
,
4799 atomic_read(&conf
->reshape_stripes
) == 0);
4800 mddev
->reshape_position
= conf
->reshape_progress
;
4801 mddev
->curr_resync_completed
= sector_nr
;
4802 conf
->reshape_checkpoint
= jiffies
;
4803 set_bit(MD_CHANGE_DEVS
, &mddev
->flags
);
4804 md_wakeup_thread(mddev
->thread
);
4805 wait_event(mddev
->sb_wait
,
4806 !test_bit(MD_CHANGE_DEVS
, &mddev
->flags
)
4807 || kthread_should_stop());
4808 spin_lock_irq(&conf
->device_lock
);
4809 conf
->reshape_safe
= mddev
->reshape_position
;
4810 spin_unlock_irq(&conf
->device_lock
);
4811 wake_up(&conf
->wait_for_overlap
);
4812 sysfs_notify(&mddev
->kobj
, NULL
, "sync_completed");
4814 return reshape_sectors
;
4817 /* FIXME go_faster isn't used */
4818 static inline sector_t
sync_request(struct mddev
*mddev
, sector_t sector_nr
, int *skipped
, int go_faster
)
4820 struct r5conf
*conf
= mddev
->private;
4821 struct stripe_head
*sh
;
4822 sector_t max_sector
= mddev
->dev_sectors
;
4823 sector_t sync_blocks
;
4824 int still_degraded
= 0;
4827 if (sector_nr
>= max_sector
) {
4828 /* just being told to finish up .. nothing much to do */
4830 if (test_bit(MD_RECOVERY_RESHAPE
, &mddev
->recovery
)) {
4835 if (mddev
->curr_resync
< max_sector
) /* aborted */
4836 bitmap_end_sync(mddev
->bitmap
, mddev
->curr_resync
,
4838 else /* completed sync */
4840 bitmap_close_sync(mddev
->bitmap
);
4845 /* Allow raid5_quiesce to complete */
4846 wait_event(conf
->wait_for_overlap
, conf
->quiesce
!= 2);
4848 if (test_bit(MD_RECOVERY_RESHAPE
, &mddev
->recovery
))
4849 return reshape_request(mddev
, sector_nr
, skipped
);
4851 /* No need to check resync_max as we never do more than one
4852 * stripe, and as resync_max will always be on a chunk boundary,
4853 * if the check in md_do_sync didn't fire, there is no chance
4854 * of overstepping resync_max here
4857 /* if there is too many failed drives and we are trying
4858 * to resync, then assert that we are finished, because there is
4859 * nothing we can do.
4861 if (mddev
->degraded
>= conf
->max_degraded
&&
4862 test_bit(MD_RECOVERY_SYNC
, &mddev
->recovery
)) {
4863 sector_t rv
= mddev
->dev_sectors
- sector_nr
;
4867 if (!test_bit(MD_RECOVERY_REQUESTED
, &mddev
->recovery
) &&
4869 !bitmap_start_sync(mddev
->bitmap
, sector_nr
, &sync_blocks
, 1) &&
4870 sync_blocks
>= STRIPE_SECTORS
) {
4871 /* we can skip this block, and probably more */
4872 sync_blocks
/= STRIPE_SECTORS
;
4874 return sync_blocks
* STRIPE_SECTORS
; /* keep things rounded to whole stripes */
4877 bitmap_cond_end_sync(mddev
->bitmap
, sector_nr
);
4879 sh
= get_active_stripe(conf
, sector_nr
, 0, 1, 0);
4881 sh
= get_active_stripe(conf
, sector_nr
, 0, 0, 0);
4882 /* make sure we don't swamp the stripe cache if someone else
4883 * is trying to get access
4885 schedule_timeout_uninterruptible(1);
4887 /* Need to check if array will still be degraded after recovery/resync
4888 * We don't need to check the 'failed' flag as when that gets set,
4891 for (i
= 0; i
< conf
->raid_disks
; i
++)
4892 if (conf
->disks
[i
].rdev
== NULL
)
4895 bitmap_start_sync(mddev
->bitmap
, sector_nr
, &sync_blocks
, still_degraded
);
4897 set_bit(STRIPE_SYNC_REQUESTED
, &sh
->state
);
4902 return STRIPE_SECTORS
;
4905 static int retry_aligned_read(struct r5conf
*conf
, struct bio
*raid_bio
)
4907 /* We may not be able to submit a whole bio at once as there
4908 * may not be enough stripe_heads available.
4909 * We cannot pre-allocate enough stripe_heads as we may need
4910 * more than exist in the cache (if we allow ever large chunks).
4911 * So we do one stripe head at a time and record in
4912 * ->bi_hw_segments how many have been done.
4914 * We *know* that this entire raid_bio is in one chunk, so
4915 * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
4917 struct stripe_head
*sh
;
4919 sector_t sector
, logical_sector
, last_sector
;
4924 logical_sector
= raid_bio
->bi_sector
& ~((sector_t
)STRIPE_SECTORS
-1);
4925 sector
= raid5_compute_sector(conf
, logical_sector
,
4927 last_sector
= bio_end_sector(raid_bio
);
4929 for (; logical_sector
< last_sector
;
4930 logical_sector
+= STRIPE_SECTORS
,
4931 sector
+= STRIPE_SECTORS
,
4934 if (scnt
< raid5_bi_processed_stripes(raid_bio
))
4935 /* already done this stripe */
4938 sh
= get_active_stripe(conf
, sector
, 0, 1, 0);
4941 /* failed to get a stripe - must wait */
4942 raid5_set_bi_processed_stripes(raid_bio
, scnt
);
4943 conf
->retry_read_aligned
= raid_bio
;
4947 if (!add_stripe_bio(sh
, raid_bio
, dd_idx
, 0)) {
4949 raid5_set_bi_processed_stripes(raid_bio
, scnt
);
4950 conf
->retry_read_aligned
= raid_bio
;
4954 set_bit(R5_ReadNoMerge
, &sh
->dev
[dd_idx
].flags
);
4959 remaining
= raid5_dec_bi_active_stripes(raid_bio
);
4960 if (remaining
== 0) {
4961 trace_block_bio_complete(bdev_get_queue(raid_bio
->bi_bdev
),
4963 bio_endio(raid_bio
, 0);
4965 if (atomic_dec_and_test(&conf
->active_aligned_reads
))
4966 wake_up(&conf
->wait_for_stripe
);
4970 static int handle_active_stripes(struct r5conf
*conf
, int group
,
4971 struct r5worker
*worker
)
4973 struct stripe_head
*batch
[MAX_STRIPE_BATCH
], *sh
;
4974 int i
, batch_size
= 0;
4976 while (batch_size
< MAX_STRIPE_BATCH
&&
4977 (sh
= __get_priority_stripe(conf
, group
)) != NULL
)
4978 batch
[batch_size
++] = sh
;
4980 if (batch_size
== 0)
4982 spin_unlock_irq(&conf
->device_lock
);
4984 for (i
= 0; i
< batch_size
; i
++)
4985 handle_stripe(batch
[i
]);
4989 spin_lock_irq(&conf
->device_lock
);
4990 for (i
= 0; i
< batch_size
; i
++)
4991 __release_stripe(conf
, batch
[i
]);
4995 static void raid5_do_work(struct work_struct
*work
)
4997 struct r5worker
*worker
= container_of(work
, struct r5worker
, work
);
4998 struct r5worker_group
*group
= worker
->group
;
4999 struct r5conf
*conf
= group
->conf
;
5000 int group_id
= group
- conf
->worker_groups
;
5002 struct blk_plug plug
;
5004 pr_debug("+++ raid5worker active\n");
5006 blk_start_plug(&plug
);
5008 spin_lock_irq(&conf
->device_lock
);
5010 int batch_size
, released
;
5012 released
= release_stripe_list(conf
);
5014 batch_size
= handle_active_stripes(conf
, group_id
, worker
);
5015 worker
->working
= false;
5016 if (!batch_size
&& !released
)
5018 handled
+= batch_size
;
5020 pr_debug("%d stripes handled\n", handled
);
5022 spin_unlock_irq(&conf
->device_lock
);
5023 blk_finish_plug(&plug
);
5025 pr_debug("--- raid5worker inactive\n");
5029 * This is our raid5 kernel thread.
5031 * We scan the hash table for stripes which can be handled now.
5032 * During the scan, completed stripes are saved for us by the interrupt
5033 * handler, so that they will not have to wait for our next wakeup.
5035 static void raid5d(struct md_thread
*thread
)
5037 struct mddev
*mddev
= thread
->mddev
;
5038 struct r5conf
*conf
= mddev
->private;
5040 struct blk_plug plug
;
5042 pr_debug("+++ raid5d active\n");
5044 md_check_recovery(mddev
);
5046 blk_start_plug(&plug
);
5048 spin_lock_irq(&conf
->device_lock
);
5051 int batch_size
, released
;
5053 released
= release_stripe_list(conf
);
5056 !list_empty(&conf
->bitmap_list
)) {
5057 /* Now is a good time to flush some bitmap updates */
5059 spin_unlock_irq(&conf
->device_lock
);
5060 bitmap_unplug(mddev
->bitmap
);
5061 spin_lock_irq(&conf
->device_lock
);
5062 conf
->seq_write
= conf
->seq_flush
;
5063 activate_bit_delay(conf
);
5065 raid5_activate_delayed(conf
);
5067 while ((bio
= remove_bio_from_retry(conf
))) {
5069 spin_unlock_irq(&conf
->device_lock
);
5070 ok
= retry_aligned_read(conf
, bio
);
5071 spin_lock_irq(&conf
->device_lock
);
5077 batch_size
= handle_active_stripes(conf
, ANY_GROUP
, NULL
);
5078 if (!batch_size
&& !released
)
5080 handled
+= batch_size
;
5082 if (mddev
->flags
& ~(1<<MD_CHANGE_PENDING
)) {
5083 spin_unlock_irq(&conf
->device_lock
);
5084 md_check_recovery(mddev
);
5085 spin_lock_irq(&conf
->device_lock
);
5088 pr_debug("%d stripes handled\n", handled
);
5090 spin_unlock_irq(&conf
->device_lock
);
5092 async_tx_issue_pending_all();
5093 blk_finish_plug(&plug
);
5095 pr_debug("--- raid5d inactive\n");
5099 raid5_show_stripe_cache_size(struct mddev
*mddev
, char *page
)
5101 struct r5conf
*conf
= mddev
->private;
5103 return sprintf(page
, "%d\n", conf
->max_nr_stripes
);
5109 raid5_set_cache_size(struct mddev
*mddev
, int size
)
5111 struct r5conf
*conf
= mddev
->private;
5114 if (size
<= 16 || size
> 32768)
5116 while (size
< conf
->max_nr_stripes
) {
5117 if (drop_one_stripe(conf
))
5118 conf
->max_nr_stripes
--;
5122 err
= md_allow_write(mddev
);
5125 while (size
> conf
->max_nr_stripes
) {
5126 if (grow_one_stripe(conf
))
5127 conf
->max_nr_stripes
++;
5132 EXPORT_SYMBOL(raid5_set_cache_size
);
5135 raid5_store_stripe_cache_size(struct mddev
*mddev
, const char *page
, size_t len
)
5137 struct r5conf
*conf
= mddev
->private;
5141 if (len
>= PAGE_SIZE
)
5146 if (kstrtoul(page
, 10, &new))
5148 err
= raid5_set_cache_size(mddev
, new);
5154 static struct md_sysfs_entry
5155 raid5_stripecache_size
= __ATTR(stripe_cache_size
, S_IRUGO
| S_IWUSR
,
5156 raid5_show_stripe_cache_size
,
5157 raid5_store_stripe_cache_size
);
5160 raid5_show_preread_threshold(struct mddev
*mddev
, char *page
)
5162 struct r5conf
*conf
= mddev
->private;
5164 return sprintf(page
, "%d\n", conf
->bypass_threshold
);
5170 raid5_store_preread_threshold(struct mddev
*mddev
, const char *page
, size_t len
)
5172 struct r5conf
*conf
= mddev
->private;
5174 if (len
>= PAGE_SIZE
)
5179 if (kstrtoul(page
, 10, &new))
5181 if (new > conf
->max_nr_stripes
)
5183 conf
->bypass_threshold
= new;
5187 static struct md_sysfs_entry
5188 raid5_preread_bypass_threshold
= __ATTR(preread_bypass_threshold
,
5190 raid5_show_preread_threshold
,
5191 raid5_store_preread_threshold
);
5194 stripe_cache_active_show(struct mddev
*mddev
, char *page
)
5196 struct r5conf
*conf
= mddev
->private;
5198 return sprintf(page
, "%d\n", atomic_read(&conf
->active_stripes
));
5203 static struct md_sysfs_entry
5204 raid5_stripecache_active
= __ATTR_RO(stripe_cache_active
);
5207 raid5_show_group_thread_cnt(struct mddev
*mddev
, char *page
)
5209 struct r5conf
*conf
= mddev
->private;
5211 return sprintf(page
, "%d\n", conf
->worker_cnt_per_group
);
5216 static int alloc_thread_groups(struct r5conf
*conf
, int cnt
);
5218 raid5_store_group_thread_cnt(struct mddev
*mddev
, const char *page
, size_t len
)
5220 struct r5conf
*conf
= mddev
->private;
5223 struct r5worker_group
*old_groups
;
5226 if (len
>= PAGE_SIZE
)
5231 if (kstrtoul(page
, 10, &new))
5234 if (new == conf
->worker_cnt_per_group
)
5237 mddev_suspend(mddev
);
5239 old_groups
= conf
->worker_groups
;
5240 old_group_cnt
= conf
->worker_cnt_per_group
;
5242 conf
->worker_groups
= NULL
;
5243 err
= alloc_thread_groups(conf
, new);
5245 conf
->worker_groups
= old_groups
;
5246 conf
->worker_cnt_per_group
= old_group_cnt
;
5249 kfree(old_groups
[0].workers
);
5253 mddev_resume(mddev
);
5260 static struct md_sysfs_entry
5261 raid5_group_thread_cnt
= __ATTR(group_thread_cnt
, S_IRUGO
| S_IWUSR
,
5262 raid5_show_group_thread_cnt
,
5263 raid5_store_group_thread_cnt
);
5265 static struct attribute
*raid5_attrs
[] = {
5266 &raid5_stripecache_size
.attr
,
5267 &raid5_stripecache_active
.attr
,
5268 &raid5_preread_bypass_threshold
.attr
,
5269 &raid5_group_thread_cnt
.attr
,
5272 static struct attribute_group raid5_attrs_group
= {
5274 .attrs
= raid5_attrs
,
5277 static int alloc_thread_groups(struct r5conf
*conf
, int cnt
)
5281 struct r5worker
*workers
;
5283 conf
->worker_cnt_per_group
= cnt
;
5285 conf
->worker_groups
= NULL
;
5288 conf
->group_cnt
= num_possible_nodes();
5289 size
= sizeof(struct r5worker
) * cnt
;
5290 workers
= kzalloc(size
* conf
->group_cnt
, GFP_NOIO
);
5291 conf
->worker_groups
= kzalloc(sizeof(struct r5worker_group
) *
5292 conf
->group_cnt
, GFP_NOIO
);
5293 if (!conf
->worker_groups
|| !workers
) {
5295 kfree(conf
->worker_groups
);
5296 conf
->worker_groups
= NULL
;
5300 for (i
= 0; i
< conf
->group_cnt
; i
++) {
5301 struct r5worker_group
*group
;
5303 group
= &conf
->worker_groups
[i
];
5304 INIT_LIST_HEAD(&group
->handle_list
);
5306 group
->workers
= workers
+ i
* cnt
;
5308 for (j
= 0; j
< cnt
; j
++) {
5309 group
->workers
[j
].group
= group
;
5310 INIT_WORK(&group
->workers
[j
].work
, raid5_do_work
);
5317 static void free_thread_groups(struct r5conf
*conf
)
5319 if (conf
->worker_groups
)
5320 kfree(conf
->worker_groups
[0].workers
);
5321 kfree(conf
->worker_groups
);
5322 conf
->worker_groups
= NULL
;
5326 raid5_size(struct mddev
*mddev
, sector_t sectors
, int raid_disks
)
5328 struct r5conf
*conf
= mddev
->private;
5331 sectors
= mddev
->dev_sectors
;
5333 /* size is defined by the smallest of previous and new size */
5334 raid_disks
= min(conf
->raid_disks
, conf
->previous_raid_disks
);
5336 sectors
&= ~((sector_t
)mddev
->chunk_sectors
- 1);
5337 sectors
&= ~((sector_t
)mddev
->new_chunk_sectors
- 1);
5338 return sectors
* (raid_disks
- conf
->max_degraded
);
5341 static void raid5_free_percpu(struct r5conf
*conf
)
5343 struct raid5_percpu
*percpu
;
5350 for_each_possible_cpu(cpu
) {
5351 percpu
= per_cpu_ptr(conf
->percpu
, cpu
);
5352 safe_put_page(percpu
->spare_page
);
5353 kfree(percpu
->scribble
);
5355 #ifdef CONFIG_HOTPLUG_CPU
5356 unregister_cpu_notifier(&conf
->cpu_notify
);
5360 free_percpu(conf
->percpu
);
5363 static void free_conf(struct r5conf
*conf
)
5365 free_thread_groups(conf
);
5366 shrink_stripes(conf
);
5367 raid5_free_percpu(conf
);
5369 kfree(conf
->stripe_hashtbl
);
5373 #ifdef CONFIG_HOTPLUG_CPU
5374 static int raid456_cpu_notify(struct notifier_block
*nfb
, unsigned long action
,
5377 struct r5conf
*conf
= container_of(nfb
, struct r5conf
, cpu_notify
);
5378 long cpu
= (long)hcpu
;
5379 struct raid5_percpu
*percpu
= per_cpu_ptr(conf
->percpu
, cpu
);
5382 case CPU_UP_PREPARE
:
5383 case CPU_UP_PREPARE_FROZEN
:
5384 if (conf
->level
== 6 && !percpu
->spare_page
)
5385 percpu
->spare_page
= alloc_page(GFP_KERNEL
);
5386 if (!percpu
->scribble
)
5387 percpu
->scribble
= kmalloc(conf
->scribble_len
, GFP_KERNEL
);
5389 if (!percpu
->scribble
||
5390 (conf
->level
== 6 && !percpu
->spare_page
)) {
5391 safe_put_page(percpu
->spare_page
);
5392 kfree(percpu
->scribble
);
5393 pr_err("%s: failed memory allocation for cpu%ld\n",
5395 return notifier_from_errno(-ENOMEM
);
5399 case CPU_DEAD_FROZEN
:
5400 safe_put_page(percpu
->spare_page
);
5401 kfree(percpu
->scribble
);
5402 percpu
->spare_page
= NULL
;
5403 percpu
->scribble
= NULL
;
5412 static int raid5_alloc_percpu(struct r5conf
*conf
)
5415 struct page
*spare_page
;
5416 struct raid5_percpu __percpu
*allcpus
;
5420 allcpus
= alloc_percpu(struct raid5_percpu
);
5423 conf
->percpu
= allcpus
;
5427 for_each_present_cpu(cpu
) {
5428 if (conf
->level
== 6) {
5429 spare_page
= alloc_page(GFP_KERNEL
);
5434 per_cpu_ptr(conf
->percpu
, cpu
)->spare_page
= spare_page
;
5436 scribble
= kmalloc(conf
->scribble_len
, GFP_KERNEL
);
5441 per_cpu_ptr(conf
->percpu
, cpu
)->scribble
= scribble
;
5443 #ifdef CONFIG_HOTPLUG_CPU
5444 conf
->cpu_notify
.notifier_call
= raid456_cpu_notify
;
5445 conf
->cpu_notify
.priority
= 0;
5447 err
= register_cpu_notifier(&conf
->cpu_notify
);
5454 static struct r5conf
*setup_conf(struct mddev
*mddev
)
5456 struct r5conf
*conf
;
5457 int raid_disk
, memory
, max_disks
;
5458 struct md_rdev
*rdev
;
5459 struct disk_info
*disk
;
5462 if (mddev
->new_level
!= 5
5463 && mddev
->new_level
!= 4
5464 && mddev
->new_level
!= 6) {
5465 printk(KERN_ERR
"md/raid:%s: raid level not set to 4/5/6 (%d)\n",
5466 mdname(mddev
), mddev
->new_level
);
5467 return ERR_PTR(-EIO
);
5469 if ((mddev
->new_level
== 5
5470 && !algorithm_valid_raid5(mddev
->new_layout
)) ||
5471 (mddev
->new_level
== 6
5472 && !algorithm_valid_raid6(mddev
->new_layout
))) {
5473 printk(KERN_ERR
"md/raid:%s: layout %d not supported\n",
5474 mdname(mddev
), mddev
->new_layout
);
5475 return ERR_PTR(-EIO
);
5477 if (mddev
->new_level
== 6 && mddev
->raid_disks
< 4) {
5478 printk(KERN_ERR
"md/raid:%s: not enough configured devices (%d, minimum 4)\n",
5479 mdname(mddev
), mddev
->raid_disks
);
5480 return ERR_PTR(-EINVAL
);
5483 if (!mddev
->new_chunk_sectors
||
5484 (mddev
->new_chunk_sectors
<< 9) % PAGE_SIZE
||
5485 !is_power_of_2(mddev
->new_chunk_sectors
)) {
5486 printk(KERN_ERR
"md/raid:%s: invalid chunk size %d\n",
5487 mdname(mddev
), mddev
->new_chunk_sectors
<< 9);
5488 return ERR_PTR(-EINVAL
);
5491 conf
= kzalloc(sizeof(struct r5conf
), GFP_KERNEL
);
5494 /* Don't enable multi-threading by default*/
5495 if (alloc_thread_groups(conf
, 0))
5497 spin_lock_init(&conf
->device_lock
);
5498 seqcount_init(&conf
->gen_lock
);
5499 init_waitqueue_head(&conf
->wait_for_stripe
);
5500 init_waitqueue_head(&conf
->wait_for_overlap
);
5501 INIT_LIST_HEAD(&conf
->handle_list
);
5502 INIT_LIST_HEAD(&conf
->hold_list
);
5503 INIT_LIST_HEAD(&conf
->delayed_list
);
5504 INIT_LIST_HEAD(&conf
->bitmap_list
);
5505 INIT_LIST_HEAD(&conf
->inactive_list
);
5506 init_llist_head(&conf
->released_stripes
);
5507 atomic_set(&conf
->active_stripes
, 0);
5508 atomic_set(&conf
->preread_active_stripes
, 0);
5509 atomic_set(&conf
->active_aligned_reads
, 0);
5510 conf
->bypass_threshold
= BYPASS_THRESHOLD
;
5511 conf
->recovery_disabled
= mddev
->recovery_disabled
- 1;
5513 conf
->raid_disks
= mddev
->raid_disks
;
5514 if (mddev
->reshape_position
== MaxSector
)
5515 conf
->previous_raid_disks
= mddev
->raid_disks
;
5517 conf
->previous_raid_disks
= mddev
->raid_disks
- mddev
->delta_disks
;
5518 max_disks
= max(conf
->raid_disks
, conf
->previous_raid_disks
);
5519 conf
->scribble_len
= scribble_len(max_disks
);
5521 conf
->disks
= kzalloc(max_disks
* sizeof(struct disk_info
),
5526 conf
->mddev
= mddev
;
5528 if ((conf
->stripe_hashtbl
= kzalloc(PAGE_SIZE
, GFP_KERNEL
)) == NULL
)
5531 conf
->level
= mddev
->new_level
;
5532 if (raid5_alloc_percpu(conf
) != 0)
5535 pr_debug("raid456: run(%s) called.\n", mdname(mddev
));
5537 rdev_for_each(rdev
, mddev
) {
5538 raid_disk
= rdev
->raid_disk
;
5539 if (raid_disk
>= max_disks
5542 disk
= conf
->disks
+ raid_disk
;
5544 if (test_bit(Replacement
, &rdev
->flags
)) {
5545 if (disk
->replacement
)
5547 disk
->replacement
= rdev
;
5554 if (test_bit(In_sync
, &rdev
->flags
)) {
5555 char b
[BDEVNAME_SIZE
];
5556 printk(KERN_INFO
"md/raid:%s: device %s operational as raid"
5558 mdname(mddev
), bdevname(rdev
->bdev
, b
), raid_disk
);
5559 } else if (rdev
->saved_raid_disk
!= raid_disk
)
5560 /* Cannot rely on bitmap to complete recovery */
5564 conf
->chunk_sectors
= mddev
->new_chunk_sectors
;
5565 conf
->level
= mddev
->new_level
;
5566 if (conf
->level
== 6)
5567 conf
->max_degraded
= 2;
5569 conf
->max_degraded
= 1;
5570 conf
->algorithm
= mddev
->new_layout
;
5571 conf
->max_nr_stripes
= NR_STRIPES
;
5572 conf
->reshape_progress
= mddev
->reshape_position
;
5573 if (conf
->reshape_progress
!= MaxSector
) {
5574 conf
->prev_chunk_sectors
= mddev
->chunk_sectors
;
5575 conf
->prev_algo
= mddev
->layout
;
5578 memory
= conf
->max_nr_stripes
* (sizeof(struct stripe_head
) +
5579 max_disks
* ((sizeof(struct bio
) + PAGE_SIZE
))) / 1024;
5580 if (grow_stripes(conf
, conf
->max_nr_stripes
)) {
5582 "md/raid:%s: couldn't allocate %dkB for buffers\n",
5583 mdname(mddev
), memory
);
5586 printk(KERN_INFO
"md/raid:%s: allocated %dkB\n",
5587 mdname(mddev
), memory
);
5589 sprintf(pers_name
, "raid%d", mddev
->new_level
);
5590 conf
->thread
= md_register_thread(raid5d
, mddev
, pers_name
);
5591 if (!conf
->thread
) {
5593 "md/raid:%s: couldn't allocate thread.\n",
5603 return ERR_PTR(-EIO
);
5605 return ERR_PTR(-ENOMEM
);
5609 static int only_parity(int raid_disk
, int algo
, int raid_disks
, int max_degraded
)
5612 case ALGORITHM_PARITY_0
:
5613 if (raid_disk
< max_degraded
)
5616 case ALGORITHM_PARITY_N
:
5617 if (raid_disk
>= raid_disks
- max_degraded
)
5620 case ALGORITHM_PARITY_0_6
:
5621 if (raid_disk
== 0 ||
5622 raid_disk
== raid_disks
- 1)
5625 case ALGORITHM_LEFT_ASYMMETRIC_6
:
5626 case ALGORITHM_RIGHT_ASYMMETRIC_6
:
5627 case ALGORITHM_LEFT_SYMMETRIC_6
:
5628 case ALGORITHM_RIGHT_SYMMETRIC_6
:
5629 if (raid_disk
== raid_disks
- 1)
5635 static int run(struct mddev
*mddev
)
5637 struct r5conf
*conf
;
5638 int working_disks
= 0;
5639 int dirty_parity_disks
= 0;
5640 struct md_rdev
*rdev
;
5641 sector_t reshape_offset
= 0;
5643 long long min_offset_diff
= 0;
5646 if (mddev
->recovery_cp
!= MaxSector
)
5647 printk(KERN_NOTICE
"md/raid:%s: not clean"
5648 " -- starting background reconstruction\n",
5651 rdev_for_each(rdev
, mddev
) {
5653 if (rdev
->raid_disk
< 0)
5655 diff
= (rdev
->new_data_offset
- rdev
->data_offset
);
5657 min_offset_diff
= diff
;
5659 } else if (mddev
->reshape_backwards
&&
5660 diff
< min_offset_diff
)
5661 min_offset_diff
= diff
;
5662 else if (!mddev
->reshape_backwards
&&
5663 diff
> min_offset_diff
)
5664 min_offset_diff
= diff
;
5667 if (mddev
->reshape_position
!= MaxSector
) {
5668 /* Check that we can continue the reshape.
5669 * Difficulties arise if the stripe we would write to
5670 * next is at or after the stripe we would read from next.
5671 * For a reshape that changes the number of devices, this
5672 * is only possible for a very short time, and mdadm makes
5673 * sure that time appears to have past before assembling
5674 * the array. So we fail if that time hasn't passed.
5675 * For a reshape that keeps the number of devices the same
5676 * mdadm must be monitoring the reshape can keeping the
5677 * critical areas read-only and backed up. It will start
5678 * the array in read-only mode, so we check for that.
5680 sector_t here_new
, here_old
;
5682 int max_degraded
= (mddev
->level
== 6 ? 2 : 1);
5684 if (mddev
->new_level
!= mddev
->level
) {
5685 printk(KERN_ERR
"md/raid:%s: unsupported reshape "
5686 "required - aborting.\n",
5690 old_disks
= mddev
->raid_disks
- mddev
->delta_disks
;
5691 /* reshape_position must be on a new-stripe boundary, and one
5692 * further up in new geometry must map after here in old
5695 here_new
= mddev
->reshape_position
;
5696 if (sector_div(here_new
, mddev
->new_chunk_sectors
*
5697 (mddev
->raid_disks
- max_degraded
))) {
5698 printk(KERN_ERR
"md/raid:%s: reshape_position not "
5699 "on a stripe boundary\n", mdname(mddev
));
5702 reshape_offset
= here_new
* mddev
->new_chunk_sectors
;
5703 /* here_new is the stripe we will write to */
5704 here_old
= mddev
->reshape_position
;
5705 sector_div(here_old
, mddev
->chunk_sectors
*
5706 (old_disks
-max_degraded
));
5707 /* here_old is the first stripe that we might need to read
5709 if (mddev
->delta_disks
== 0) {
5710 if ((here_new
* mddev
->new_chunk_sectors
!=
5711 here_old
* mddev
->chunk_sectors
)) {
5712 printk(KERN_ERR
"md/raid:%s: reshape position is"
5713 " confused - aborting\n", mdname(mddev
));
5716 /* We cannot be sure it is safe to start an in-place
5717 * reshape. It is only safe if user-space is monitoring
5718 * and taking constant backups.
5719 * mdadm always starts a situation like this in
5720 * readonly mode so it can take control before
5721 * allowing any writes. So just check for that.
5723 if (abs(min_offset_diff
) >= mddev
->chunk_sectors
&&
5724 abs(min_offset_diff
) >= mddev
->new_chunk_sectors
)
5725 /* not really in-place - so OK */;
5726 else if (mddev
->ro
== 0) {
5727 printk(KERN_ERR
"md/raid:%s: in-place reshape "
5728 "must be started in read-only mode "
5733 } else if (mddev
->reshape_backwards
5734 ? (here_new
* mddev
->new_chunk_sectors
+ min_offset_diff
<=
5735 here_old
* mddev
->chunk_sectors
)
5736 : (here_new
* mddev
->new_chunk_sectors
>=
5737 here_old
* mddev
->chunk_sectors
+ (-min_offset_diff
))) {
5738 /* Reading from the same stripe as writing to - bad */
5739 printk(KERN_ERR
"md/raid:%s: reshape_position too early for "
5740 "auto-recovery - aborting.\n",
5744 printk(KERN_INFO
"md/raid:%s: reshape will continue\n",
5746 /* OK, we should be able to continue; */
5748 BUG_ON(mddev
->level
!= mddev
->new_level
);
5749 BUG_ON(mddev
->layout
!= mddev
->new_layout
);
5750 BUG_ON(mddev
->chunk_sectors
!= mddev
->new_chunk_sectors
);
5751 BUG_ON(mddev
->delta_disks
!= 0);
5754 if (mddev
->private == NULL
)
5755 conf
= setup_conf(mddev
);
5757 conf
= mddev
->private;
5760 return PTR_ERR(conf
);
5762 conf
->min_offset_diff
= min_offset_diff
;
5763 mddev
->thread
= conf
->thread
;
5764 conf
->thread
= NULL
;
5765 mddev
->private = conf
;
5767 for (i
= 0; i
< conf
->raid_disks
&& conf
->previous_raid_disks
;
5769 rdev
= conf
->disks
[i
].rdev
;
5770 if (!rdev
&& conf
->disks
[i
].replacement
) {
5771 /* The replacement is all we have yet */
5772 rdev
= conf
->disks
[i
].replacement
;
5773 conf
->disks
[i
].replacement
= NULL
;
5774 clear_bit(Replacement
, &rdev
->flags
);
5775 conf
->disks
[i
].rdev
= rdev
;
5779 if (conf
->disks
[i
].replacement
&&
5780 conf
->reshape_progress
!= MaxSector
) {
5781 /* replacements and reshape simply do not mix. */
5782 printk(KERN_ERR
"md: cannot handle concurrent "
5783 "replacement and reshape.\n");
5786 if (test_bit(In_sync
, &rdev
->flags
)) {
5790 /* This disc is not fully in-sync. However if it
5791 * just stored parity (beyond the recovery_offset),
5792 * when we don't need to be concerned about the
5793 * array being dirty.
5794 * When reshape goes 'backwards', we never have
5795 * partially completed devices, so we only need
5796 * to worry about reshape going forwards.
5798 /* Hack because v0.91 doesn't store recovery_offset properly. */
5799 if (mddev
->major_version
== 0 &&
5800 mddev
->minor_version
> 90)
5801 rdev
->recovery_offset
= reshape_offset
;
5803 if (rdev
->recovery_offset
< reshape_offset
) {
5804 /* We need to check old and new layout */
5805 if (!only_parity(rdev
->raid_disk
,
5808 conf
->max_degraded
))
5811 if (!only_parity(rdev
->raid_disk
,
5813 conf
->previous_raid_disks
,
5814 conf
->max_degraded
))
5816 dirty_parity_disks
++;
5820 * 0 for a fully functional array, 1 or 2 for a degraded array.
5822 mddev
->degraded
= calc_degraded(conf
);
5824 if (has_failed(conf
)) {
5825 printk(KERN_ERR
"md/raid:%s: not enough operational devices"
5826 " (%d/%d failed)\n",
5827 mdname(mddev
), mddev
->degraded
, conf
->raid_disks
);
5831 /* device size must be a multiple of chunk size */
5832 mddev
->dev_sectors
&= ~(mddev
->chunk_sectors
- 1);
5833 mddev
->resync_max_sectors
= mddev
->dev_sectors
;
5835 if (mddev
->degraded
> dirty_parity_disks
&&
5836 mddev
->recovery_cp
!= MaxSector
) {
5837 if (mddev
->ok_start_degraded
)
5839 "md/raid:%s: starting dirty degraded array"
5840 " - data corruption possible.\n",
5844 "md/raid:%s: cannot start dirty degraded array.\n",
5850 if (mddev
->degraded
== 0)
5851 printk(KERN_INFO
"md/raid:%s: raid level %d active with %d out of %d"
5852 " devices, algorithm %d\n", mdname(mddev
), conf
->level
,
5853 mddev
->raid_disks
-mddev
->degraded
, mddev
->raid_disks
,
5856 printk(KERN_ALERT
"md/raid:%s: raid level %d active with %d"
5857 " out of %d devices, algorithm %d\n",
5858 mdname(mddev
), conf
->level
,
5859 mddev
->raid_disks
- mddev
->degraded
,
5860 mddev
->raid_disks
, mddev
->new_layout
);
5862 print_raid5_conf(conf
);
5864 if (conf
->reshape_progress
!= MaxSector
) {
5865 conf
->reshape_safe
= conf
->reshape_progress
;
5866 atomic_set(&conf
->reshape_stripes
, 0);
5867 clear_bit(MD_RECOVERY_SYNC
, &mddev
->recovery
);
5868 clear_bit(MD_RECOVERY_CHECK
, &mddev
->recovery
);
5869 set_bit(MD_RECOVERY_RESHAPE
, &mddev
->recovery
);
5870 set_bit(MD_RECOVERY_RUNNING
, &mddev
->recovery
);
5871 mddev
->sync_thread
= md_register_thread(md_do_sync
, mddev
,
5876 /* Ok, everything is just fine now */
5877 if (mddev
->to_remove
== &raid5_attrs_group
)
5878 mddev
->to_remove
= NULL
;
5879 else if (mddev
->kobj
.sd
&&
5880 sysfs_create_group(&mddev
->kobj
, &raid5_attrs_group
))
5882 "raid5: failed to create sysfs attributes for %s\n",
5884 md_set_array_sectors(mddev
, raid5_size(mddev
, 0, 0));
5888 bool discard_supported
= true;
5889 /* read-ahead size must cover two whole stripes, which
5890 * is 2 * (datadisks) * chunksize where 'n' is the
5891 * number of raid devices
5893 int data_disks
= conf
->previous_raid_disks
- conf
->max_degraded
;
5894 int stripe
= data_disks
*
5895 ((mddev
->chunk_sectors
<< 9) / PAGE_SIZE
);
5896 if (mddev
->queue
->backing_dev_info
.ra_pages
< 2 * stripe
)
5897 mddev
->queue
->backing_dev_info
.ra_pages
= 2 * stripe
;
5899 blk_queue_merge_bvec(mddev
->queue
, raid5_mergeable_bvec
);
5901 mddev
->queue
->backing_dev_info
.congested_data
= mddev
;
5902 mddev
->queue
->backing_dev_info
.congested_fn
= raid5_congested
;
5904 chunk_size
= mddev
->chunk_sectors
<< 9;
5905 blk_queue_io_min(mddev
->queue
, chunk_size
);
5906 blk_queue_io_opt(mddev
->queue
, chunk_size
*
5907 (conf
->raid_disks
- conf
->max_degraded
));
5909 * We can only discard a whole stripe. It doesn't make sense to
5910 * discard data disk but write parity disk
5912 stripe
= stripe
* PAGE_SIZE
;
5913 /* Round up to power of 2, as discard handling
5914 * currently assumes that */
5915 while ((stripe
-1) & stripe
)
5916 stripe
= (stripe
| (stripe
-1)) + 1;
5917 mddev
->queue
->limits
.discard_alignment
= stripe
;
5918 mddev
->queue
->limits
.discard_granularity
= stripe
;
5920 * unaligned part of discard request will be ignored, so can't
5921 * guarantee discard_zerors_data
5923 mddev
->queue
->limits
.discard_zeroes_data
= 0;
5925 blk_queue_max_write_same_sectors(mddev
->queue
, 0);
5927 rdev_for_each(rdev
, mddev
) {
5928 disk_stack_limits(mddev
->gendisk
, rdev
->bdev
,
5929 rdev
->data_offset
<< 9);
5930 disk_stack_limits(mddev
->gendisk
, rdev
->bdev
,
5931 rdev
->new_data_offset
<< 9);
5933 * discard_zeroes_data is required, otherwise data
5934 * could be lost. Consider a scenario: discard a stripe
5935 * (the stripe could be inconsistent if
5936 * discard_zeroes_data is 0); write one disk of the
5937 * stripe (the stripe could be inconsistent again
5938 * depending on which disks are used to calculate
5939 * parity); the disk is broken; The stripe data of this
5942 if (!blk_queue_discard(bdev_get_queue(rdev
->bdev
)) ||
5943 !bdev_get_queue(rdev
->bdev
)->
5944 limits
.discard_zeroes_data
)
5945 discard_supported
= false;
5948 if (discard_supported
&&
5949 mddev
->queue
->limits
.max_discard_sectors
>= stripe
&&
5950 mddev
->queue
->limits
.discard_granularity
>= stripe
)
5951 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD
,
5954 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD
,
5960 md_unregister_thread(&mddev
->thread
);
5961 print_raid5_conf(conf
);
5963 mddev
->private = NULL
;
5964 printk(KERN_ALERT
"md/raid:%s: failed to run raid set.\n", mdname(mddev
));
5968 static int stop(struct mddev
*mddev
)
5970 struct r5conf
*conf
= mddev
->private;
5972 md_unregister_thread(&mddev
->thread
);
5974 mddev
->queue
->backing_dev_info
.congested_fn
= NULL
;
5976 mddev
->private = NULL
;
5977 mddev
->to_remove
= &raid5_attrs_group
;
5981 static void status(struct seq_file
*seq
, struct mddev
*mddev
)
5983 struct r5conf
*conf
= mddev
->private;
5986 seq_printf(seq
, " level %d, %dk chunk, algorithm %d", mddev
->level
,
5987 mddev
->chunk_sectors
/ 2, mddev
->layout
);
5988 seq_printf (seq
, " [%d/%d] [", conf
->raid_disks
, conf
->raid_disks
- mddev
->degraded
);
5989 for (i
= 0; i
< conf
->raid_disks
; i
++)
5990 seq_printf (seq
, "%s",
5991 conf
->disks
[i
].rdev
&&
5992 test_bit(In_sync
, &conf
->disks
[i
].rdev
->flags
) ? "U" : "_");
5993 seq_printf (seq
, "]");
5996 static void print_raid5_conf (struct r5conf
*conf
)
5999 struct disk_info
*tmp
;
6001 printk(KERN_DEBUG
"RAID conf printout:\n");
6003 printk("(conf==NULL)\n");
6006 printk(KERN_DEBUG
" --- level:%d rd:%d wd:%d\n", conf
->level
,
6008 conf
->raid_disks
- conf
->mddev
->degraded
);
6010 for (i
= 0; i
< conf
->raid_disks
; i
++) {
6011 char b
[BDEVNAME_SIZE
];
6012 tmp
= conf
->disks
+ i
;
6014 printk(KERN_DEBUG
" disk %d, o:%d, dev:%s\n",
6015 i
, !test_bit(Faulty
, &tmp
->rdev
->flags
),
6016 bdevname(tmp
->rdev
->bdev
, b
));
6020 static int raid5_spare_active(struct mddev
*mddev
)
6023 struct r5conf
*conf
= mddev
->private;
6024 struct disk_info
*tmp
;
6026 unsigned long flags
;
6028 for (i
= 0; i
< conf
->raid_disks
; i
++) {
6029 tmp
= conf
->disks
+ i
;
6030 if (tmp
->replacement
6031 && tmp
->replacement
->recovery_offset
== MaxSector
6032 && !test_bit(Faulty
, &tmp
->replacement
->flags
)
6033 && !test_and_set_bit(In_sync
, &tmp
->replacement
->flags
)) {
6034 /* Replacement has just become active. */
6036 || !test_and_clear_bit(In_sync
, &tmp
->rdev
->flags
))
6039 /* Replaced device not technically faulty,
6040 * but we need to be sure it gets removed
6041 * and never re-added.
6043 set_bit(Faulty
, &tmp
->rdev
->flags
);
6044 sysfs_notify_dirent_safe(
6045 tmp
->rdev
->sysfs_state
);
6047 sysfs_notify_dirent_safe(tmp
->replacement
->sysfs_state
);
6048 } else if (tmp
->rdev
6049 && tmp
->rdev
->recovery_offset
== MaxSector
6050 && !test_bit(Faulty
, &tmp
->rdev
->flags
)
6051 && !test_and_set_bit(In_sync
, &tmp
->rdev
->flags
)) {
6053 sysfs_notify_dirent_safe(tmp
->rdev
->sysfs_state
);
6056 spin_lock_irqsave(&conf
->device_lock
, flags
);
6057 mddev
->degraded
= calc_degraded(conf
);
6058 spin_unlock_irqrestore(&conf
->device_lock
, flags
);
6059 print_raid5_conf(conf
);
6063 static int raid5_remove_disk(struct mddev
*mddev
, struct md_rdev
*rdev
)
6065 struct r5conf
*conf
= mddev
->private;
6067 int number
= rdev
->raid_disk
;
6068 struct md_rdev
**rdevp
;
6069 struct disk_info
*p
= conf
->disks
+ number
;
6071 print_raid5_conf(conf
);
6072 if (rdev
== p
->rdev
)
6074 else if (rdev
== p
->replacement
)
6075 rdevp
= &p
->replacement
;
6079 if (number
>= conf
->raid_disks
&&
6080 conf
->reshape_progress
== MaxSector
)
6081 clear_bit(In_sync
, &rdev
->flags
);
6083 if (test_bit(In_sync
, &rdev
->flags
) ||
6084 atomic_read(&rdev
->nr_pending
)) {
6088 /* Only remove non-faulty devices if recovery
6091 if (!test_bit(Faulty
, &rdev
->flags
) &&
6092 mddev
->recovery_disabled
!= conf
->recovery_disabled
&&
6093 !has_failed(conf
) &&
6094 (!p
->replacement
|| p
->replacement
== rdev
) &&
6095 number
< conf
->raid_disks
) {
6101 if (atomic_read(&rdev
->nr_pending
)) {
6102 /* lost the race, try later */
6105 } else if (p
->replacement
) {
6106 /* We must have just cleared 'rdev' */
6107 p
->rdev
= p
->replacement
;
6108 clear_bit(Replacement
, &p
->replacement
->flags
);
6109 smp_mb(); /* Make sure other CPUs may see both as identical
6110 * but will never see neither - if they are careful
6112 p
->replacement
= NULL
;
6113 clear_bit(WantReplacement
, &rdev
->flags
);
6115 /* We might have just removed the Replacement as faulty-
6116 * clear the bit just in case
6118 clear_bit(WantReplacement
, &rdev
->flags
);
6121 print_raid5_conf(conf
);
6125 static int raid5_add_disk(struct mddev
*mddev
, struct md_rdev
*rdev
)
6127 struct r5conf
*conf
= mddev
->private;
6130 struct disk_info
*p
;
6132 int last
= conf
->raid_disks
- 1;
6134 if (mddev
->recovery_disabled
== conf
->recovery_disabled
)
6137 if (rdev
->saved_raid_disk
< 0 && has_failed(conf
))
6138 /* no point adding a device */
6141 if (rdev
->raid_disk
>= 0)
6142 first
= last
= rdev
->raid_disk
;
6145 * find the disk ... but prefer rdev->saved_raid_disk
6148 if (rdev
->saved_raid_disk
>= 0 &&
6149 rdev
->saved_raid_disk
>= first
&&
6150 conf
->disks
[rdev
->saved_raid_disk
].rdev
== NULL
)
6151 first
= rdev
->saved_raid_disk
;
6153 for (disk
= first
; disk
<= last
; disk
++) {
6154 p
= conf
->disks
+ disk
;
6155 if (p
->rdev
== NULL
) {
6156 clear_bit(In_sync
, &rdev
->flags
);
6157 rdev
->raid_disk
= disk
;
6159 if (rdev
->saved_raid_disk
!= disk
)
6161 rcu_assign_pointer(p
->rdev
, rdev
);
6165 for (disk
= first
; disk
<= last
; disk
++) {
6166 p
= conf
->disks
+ disk
;
6167 if (test_bit(WantReplacement
, &p
->rdev
->flags
) &&
6168 p
->replacement
== NULL
) {
6169 clear_bit(In_sync
, &rdev
->flags
);
6170 set_bit(Replacement
, &rdev
->flags
);
6171 rdev
->raid_disk
= disk
;
6174 rcu_assign_pointer(p
->replacement
, rdev
);
6179 print_raid5_conf(conf
);
6183 static int raid5_resize(struct mddev
*mddev
, sector_t sectors
)
6185 /* no resync is happening, and there is enough space
6186 * on all devices, so we can resize.
6187 * We need to make sure resync covers any new space.
6188 * If the array is shrinking we should possibly wait until
6189 * any io in the removed space completes, but it hardly seems
6193 sectors
&= ~((sector_t
)mddev
->chunk_sectors
- 1);
6194 newsize
= raid5_size(mddev
, sectors
, mddev
->raid_disks
);
6195 if (mddev
->external_size
&&
6196 mddev
->array_sectors
> newsize
)
6198 if (mddev
->bitmap
) {
6199 int ret
= bitmap_resize(mddev
->bitmap
, sectors
, 0, 0);
6203 md_set_array_sectors(mddev
, newsize
);
6204 set_capacity(mddev
->gendisk
, mddev
->array_sectors
);
6205 revalidate_disk(mddev
->gendisk
);
6206 if (sectors
> mddev
->dev_sectors
&&
6207 mddev
->recovery_cp
> mddev
->dev_sectors
) {
6208 mddev
->recovery_cp
= mddev
->dev_sectors
;
6209 set_bit(MD_RECOVERY_NEEDED
, &mddev
->recovery
);
6211 mddev
->dev_sectors
= sectors
;
6212 mddev
->resync_max_sectors
= sectors
;
6216 static int check_stripe_cache(struct mddev
*mddev
)
6218 /* Can only proceed if there are plenty of stripe_heads.
6219 * We need a minimum of one full stripe,, and for sensible progress
6220 * it is best to have about 4 times that.
6221 * If we require 4 times, then the default 256 4K stripe_heads will
6222 * allow for chunk sizes up to 256K, which is probably OK.
6223 * If the chunk size is greater, user-space should request more
6224 * stripe_heads first.
6226 struct r5conf
*conf
= mddev
->private;
6227 if (((mddev
->chunk_sectors
<< 9) / STRIPE_SIZE
) * 4
6228 > conf
->max_nr_stripes
||
6229 ((mddev
->new_chunk_sectors
<< 9) / STRIPE_SIZE
) * 4
6230 > conf
->max_nr_stripes
) {
6231 printk(KERN_WARNING
"md/raid:%s: reshape: not enough stripes. Needed %lu\n",
6233 ((max(mddev
->chunk_sectors
, mddev
->new_chunk_sectors
) << 9)
6240 static int check_reshape(struct mddev
*mddev
)
6242 struct r5conf
*conf
= mddev
->private;
6244 if (mddev
->delta_disks
== 0 &&
6245 mddev
->new_layout
== mddev
->layout
&&
6246 mddev
->new_chunk_sectors
== mddev
->chunk_sectors
)
6247 return 0; /* nothing to do */
6248 if (has_failed(conf
))
6250 if (mddev
->delta_disks
< 0 && mddev
->reshape_position
== MaxSector
) {
6251 /* We might be able to shrink, but the devices must
6252 * be made bigger first.
6253 * For raid6, 4 is the minimum size.
6254 * Otherwise 2 is the minimum
6257 if (mddev
->level
== 6)
6259 if (mddev
->raid_disks
+ mddev
->delta_disks
< min
)
6263 if (!check_stripe_cache(mddev
))
6266 return resize_stripes(conf
, (conf
->previous_raid_disks
6267 + mddev
->delta_disks
));
6270 static int raid5_start_reshape(struct mddev
*mddev
)
6272 struct r5conf
*conf
= mddev
->private;
6273 struct md_rdev
*rdev
;
6275 unsigned long flags
;
6277 if (test_bit(MD_RECOVERY_RUNNING
, &mddev
->recovery
))
6280 if (!check_stripe_cache(mddev
))
6283 if (has_failed(conf
))
6286 rdev_for_each(rdev
, mddev
) {
6287 if (!test_bit(In_sync
, &rdev
->flags
)
6288 && !test_bit(Faulty
, &rdev
->flags
))
6292 if (spares
- mddev
->degraded
< mddev
->delta_disks
- conf
->max_degraded
)
6293 /* Not enough devices even to make a degraded array
6298 /* Refuse to reduce size of the array. Any reductions in
6299 * array size must be through explicit setting of array_size
6302 if (raid5_size(mddev
, 0, conf
->raid_disks
+ mddev
->delta_disks
)
6303 < mddev
->array_sectors
) {
6304 printk(KERN_ERR
"md/raid:%s: array size must be reduced "
6305 "before number of disks\n", mdname(mddev
));
6309 atomic_set(&conf
->reshape_stripes
, 0);
6310 spin_lock_irq(&conf
->device_lock
);
6311 write_seqcount_begin(&conf
->gen_lock
);
6312 conf
->previous_raid_disks
= conf
->raid_disks
;
6313 conf
->raid_disks
+= mddev
->delta_disks
;
6314 conf
->prev_chunk_sectors
= conf
->chunk_sectors
;
6315 conf
->chunk_sectors
= mddev
->new_chunk_sectors
;
6316 conf
->prev_algo
= conf
->algorithm
;
6317 conf
->algorithm
= mddev
->new_layout
;
6319 /* Code that selects data_offset needs to see the generation update
6320 * if reshape_progress has been set - so a memory barrier needed.
6323 if (mddev
->reshape_backwards
)
6324 conf
->reshape_progress
= raid5_size(mddev
, 0, 0);
6326 conf
->reshape_progress
= 0;
6327 conf
->reshape_safe
= conf
->reshape_progress
;
6328 write_seqcount_end(&conf
->gen_lock
);
6329 spin_unlock_irq(&conf
->device_lock
);
6331 /* Now make sure any requests that proceeded on the assumption
6332 * the reshape wasn't running - like Discard or Read - have
6335 mddev_suspend(mddev
);
6336 mddev_resume(mddev
);
6338 /* Add some new drives, as many as will fit.
6339 * We know there are enough to make the newly sized array work.
6340 * Don't add devices if we are reducing the number of
6341 * devices in the array. This is because it is not possible
6342 * to correctly record the "partially reconstructed" state of
6343 * such devices during the reshape and confusion could result.
6345 if (mddev
->delta_disks
>= 0) {
6346 rdev_for_each(rdev
, mddev
)
6347 if (rdev
->raid_disk
< 0 &&
6348 !test_bit(Faulty
, &rdev
->flags
)) {
6349 if (raid5_add_disk(mddev
, rdev
) == 0) {
6351 >= conf
->previous_raid_disks
)
6352 set_bit(In_sync
, &rdev
->flags
);
6354 rdev
->recovery_offset
= 0;
6356 if (sysfs_link_rdev(mddev
, rdev
))
6357 /* Failure here is OK */;
6359 } else if (rdev
->raid_disk
>= conf
->previous_raid_disks
6360 && !test_bit(Faulty
, &rdev
->flags
)) {
6361 /* This is a spare that was manually added */
6362 set_bit(In_sync
, &rdev
->flags
);
6365 /* When a reshape changes the number of devices,
6366 * ->degraded is measured against the larger of the
6367 * pre and post number of devices.
6369 spin_lock_irqsave(&conf
->device_lock
, flags
);
6370 mddev
->degraded
= calc_degraded(conf
);
6371 spin_unlock_irqrestore(&conf
->device_lock
, flags
);
6373 mddev
->raid_disks
= conf
->raid_disks
;
6374 mddev
->reshape_position
= conf
->reshape_progress
;
6375 set_bit(MD_CHANGE_DEVS
, &mddev
->flags
);
6377 clear_bit(MD_RECOVERY_SYNC
, &mddev
->recovery
);
6378 clear_bit(MD_RECOVERY_CHECK
, &mddev
->recovery
);
6379 set_bit(MD_RECOVERY_RESHAPE
, &mddev
->recovery
);
6380 set_bit(MD_RECOVERY_RUNNING
, &mddev
->recovery
);
6381 mddev
->sync_thread
= md_register_thread(md_do_sync
, mddev
,
6383 if (!mddev
->sync_thread
) {
6384 mddev
->recovery
= 0;
6385 spin_lock_irq(&conf
->device_lock
);
6386 mddev
->raid_disks
= conf
->raid_disks
= conf
->previous_raid_disks
;
6387 rdev_for_each(rdev
, mddev
)
6388 rdev
->new_data_offset
= rdev
->data_offset
;
6390 conf
->reshape_progress
= MaxSector
;
6391 mddev
->reshape_position
= MaxSector
;
6392 spin_unlock_irq(&conf
->device_lock
);
6395 conf
->reshape_checkpoint
= jiffies
;
6396 md_wakeup_thread(mddev
->sync_thread
);
6397 md_new_event(mddev
);
6401 /* This is called from the reshape thread and should make any
6402 * changes needed in 'conf'
6404 static void end_reshape(struct r5conf
*conf
)
6407 if (!test_bit(MD_RECOVERY_INTR
, &conf
->mddev
->recovery
)) {
6408 struct md_rdev
*rdev
;
6410 spin_lock_irq(&conf
->device_lock
);
6411 conf
->previous_raid_disks
= conf
->raid_disks
;
6412 rdev_for_each(rdev
, conf
->mddev
)
6413 rdev
->data_offset
= rdev
->new_data_offset
;
6415 conf
->reshape_progress
= MaxSector
;
6416 spin_unlock_irq(&conf
->device_lock
);
6417 wake_up(&conf
->wait_for_overlap
);
6419 /* read-ahead size must cover two whole stripes, which is
6420 * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
6422 if (conf
->mddev
->queue
) {
6423 int data_disks
= conf
->raid_disks
- conf
->max_degraded
;
6424 int stripe
= data_disks
* ((conf
->chunk_sectors
<< 9)
6426 if (conf
->mddev
->queue
->backing_dev_info
.ra_pages
< 2 * stripe
)
6427 conf
->mddev
->queue
->backing_dev_info
.ra_pages
= 2 * stripe
;
6432 /* This is called from the raid5d thread with mddev_lock held.
6433 * It makes config changes to the device.
6435 static void raid5_finish_reshape(struct mddev
*mddev
)
6437 struct r5conf
*conf
= mddev
->private;
6439 if (!test_bit(MD_RECOVERY_INTR
, &mddev
->recovery
)) {
6441 if (mddev
->delta_disks
> 0) {
6442 md_set_array_sectors(mddev
, raid5_size(mddev
, 0, 0));
6443 set_capacity(mddev
->gendisk
, mddev
->array_sectors
);
6444 revalidate_disk(mddev
->gendisk
);
6447 spin_lock_irq(&conf
->device_lock
);
6448 mddev
->degraded
= calc_degraded(conf
);
6449 spin_unlock_irq(&conf
->device_lock
);
6450 for (d
= conf
->raid_disks
;
6451 d
< conf
->raid_disks
- mddev
->delta_disks
;
6453 struct md_rdev
*rdev
= conf
->disks
[d
].rdev
;
6455 clear_bit(In_sync
, &rdev
->flags
);
6456 rdev
= conf
->disks
[d
].replacement
;
6458 clear_bit(In_sync
, &rdev
->flags
);
6461 mddev
->layout
= conf
->algorithm
;
6462 mddev
->chunk_sectors
= conf
->chunk_sectors
;
6463 mddev
->reshape_position
= MaxSector
;
6464 mddev
->delta_disks
= 0;
6465 mddev
->reshape_backwards
= 0;
6469 static void raid5_quiesce(struct mddev
*mddev
, int state
)
6471 struct r5conf
*conf
= mddev
->private;
6474 case 2: /* resume for a suspend */
6475 wake_up(&conf
->wait_for_overlap
);
6478 case 1: /* stop all writes */
6479 spin_lock_irq(&conf
->device_lock
);
6480 /* '2' tells resync/reshape to pause so that all
6481 * active stripes can drain
6484 wait_event_lock_irq(conf
->wait_for_stripe
,
6485 atomic_read(&conf
->active_stripes
) == 0 &&
6486 atomic_read(&conf
->active_aligned_reads
) == 0,
6489 spin_unlock_irq(&conf
->device_lock
);
6490 /* allow reshape to continue */
6491 wake_up(&conf
->wait_for_overlap
);
6494 case 0: /* re-enable writes */
6495 spin_lock_irq(&conf
->device_lock
);
6497 wake_up(&conf
->wait_for_stripe
);
6498 wake_up(&conf
->wait_for_overlap
);
6499 spin_unlock_irq(&conf
->device_lock
);
6505 static void *raid45_takeover_raid0(struct mddev
*mddev
, int level
)
6507 struct r0conf
*raid0_conf
= mddev
->private;
6510 /* for raid0 takeover only one zone is supported */
6511 if (raid0_conf
->nr_strip_zones
> 1) {
6512 printk(KERN_ERR
"md/raid:%s: cannot takeover raid0 with more than one zone.\n",
6514 return ERR_PTR(-EINVAL
);
6517 sectors
= raid0_conf
->strip_zone
[0].zone_end
;
6518 sector_div(sectors
, raid0_conf
->strip_zone
[0].nb_dev
);
6519 mddev
->dev_sectors
= sectors
;
6520 mddev
->new_level
= level
;
6521 mddev
->new_layout
= ALGORITHM_PARITY_N
;
6522 mddev
->new_chunk_sectors
= mddev
->chunk_sectors
;
6523 mddev
->raid_disks
+= 1;
6524 mddev
->delta_disks
= 1;
6525 /* make sure it will be not marked as dirty */
6526 mddev
->recovery_cp
= MaxSector
;
6528 return setup_conf(mddev
);
6532 static void *raid5_takeover_raid1(struct mddev
*mddev
)
6536 if (mddev
->raid_disks
!= 2 ||
6537 mddev
->degraded
> 1)
6538 return ERR_PTR(-EINVAL
);
6540 /* Should check if there are write-behind devices? */
6542 chunksect
= 64*2; /* 64K by default */
6544 /* The array must be an exact multiple of chunksize */
6545 while (chunksect
&& (mddev
->array_sectors
& (chunksect
-1)))
6548 if ((chunksect
<<9) < STRIPE_SIZE
)
6549 /* array size does not allow a suitable chunk size */
6550 return ERR_PTR(-EINVAL
);
6552 mddev
->new_level
= 5;
6553 mddev
->new_layout
= ALGORITHM_LEFT_SYMMETRIC
;
6554 mddev
->new_chunk_sectors
= chunksect
;
6556 return setup_conf(mddev
);
6559 static void *raid5_takeover_raid6(struct mddev
*mddev
)
6563 switch (mddev
->layout
) {
6564 case ALGORITHM_LEFT_ASYMMETRIC_6
:
6565 new_layout
= ALGORITHM_LEFT_ASYMMETRIC
;
6567 case ALGORITHM_RIGHT_ASYMMETRIC_6
:
6568 new_layout
= ALGORITHM_RIGHT_ASYMMETRIC
;
6570 case ALGORITHM_LEFT_SYMMETRIC_6
:
6571 new_layout
= ALGORITHM_LEFT_SYMMETRIC
;
6573 case ALGORITHM_RIGHT_SYMMETRIC_6
:
6574 new_layout
= ALGORITHM_RIGHT_SYMMETRIC
;
6576 case ALGORITHM_PARITY_0_6
:
6577 new_layout
= ALGORITHM_PARITY_0
;
6579 case ALGORITHM_PARITY_N
:
6580 new_layout
= ALGORITHM_PARITY_N
;
6583 return ERR_PTR(-EINVAL
);
6585 mddev
->new_level
= 5;
6586 mddev
->new_layout
= new_layout
;
6587 mddev
->delta_disks
= -1;
6588 mddev
->raid_disks
-= 1;
6589 return setup_conf(mddev
);
6593 static int raid5_check_reshape(struct mddev
*mddev
)
6595 /* For a 2-drive array, the layout and chunk size can be changed
6596 * immediately as not restriping is needed.
6597 * For larger arrays we record the new value - after validation
6598 * to be used by a reshape pass.
6600 struct r5conf
*conf
= mddev
->private;
6601 int new_chunk
= mddev
->new_chunk_sectors
;
6603 if (mddev
->new_layout
>= 0 && !algorithm_valid_raid5(mddev
->new_layout
))
6605 if (new_chunk
> 0) {
6606 if (!is_power_of_2(new_chunk
))
6608 if (new_chunk
< (PAGE_SIZE
>>9))
6610 if (mddev
->array_sectors
& (new_chunk
-1))
6611 /* not factor of array size */
6615 /* They look valid */
6617 if (mddev
->raid_disks
== 2) {
6618 /* can make the change immediately */
6619 if (mddev
->new_layout
>= 0) {
6620 conf
->algorithm
= mddev
->new_layout
;
6621 mddev
->layout
= mddev
->new_layout
;
6623 if (new_chunk
> 0) {
6624 conf
->chunk_sectors
= new_chunk
;
6625 mddev
->chunk_sectors
= new_chunk
;
6627 set_bit(MD_CHANGE_DEVS
, &mddev
->flags
);
6628 md_wakeup_thread(mddev
->thread
);
6630 return check_reshape(mddev
);
6633 static int raid6_check_reshape(struct mddev
*mddev
)
6635 int new_chunk
= mddev
->new_chunk_sectors
;
6637 if (mddev
->new_layout
>= 0 && !algorithm_valid_raid6(mddev
->new_layout
))
6639 if (new_chunk
> 0) {
6640 if (!is_power_of_2(new_chunk
))
6642 if (new_chunk
< (PAGE_SIZE
>> 9))
6644 if (mddev
->array_sectors
& (new_chunk
-1))
6645 /* not factor of array size */
6649 /* They look valid */
6650 return check_reshape(mddev
);
6653 static void *raid5_takeover(struct mddev
*mddev
)
6655 /* raid5 can take over:
6656 * raid0 - if there is only one strip zone - make it a raid4 layout
6657 * raid1 - if there are two drives. We need to know the chunk size
6658 * raid4 - trivial - just use a raid4 layout.
6659 * raid6 - Providing it is a *_6 layout
6661 if (mddev
->level
== 0)
6662 return raid45_takeover_raid0(mddev
, 5);
6663 if (mddev
->level
== 1)
6664 return raid5_takeover_raid1(mddev
);
6665 if (mddev
->level
== 4) {
6666 mddev
->new_layout
= ALGORITHM_PARITY_N
;
6667 mddev
->new_level
= 5;
6668 return setup_conf(mddev
);
6670 if (mddev
->level
== 6)
6671 return raid5_takeover_raid6(mddev
);
6673 return ERR_PTR(-EINVAL
);
6676 static void *raid4_takeover(struct mddev
*mddev
)
6678 /* raid4 can take over:
6679 * raid0 - if there is only one strip zone
6680 * raid5 - if layout is right
6682 if (mddev
->level
== 0)
6683 return raid45_takeover_raid0(mddev
, 4);
6684 if (mddev
->level
== 5 &&
6685 mddev
->layout
== ALGORITHM_PARITY_N
) {
6686 mddev
->new_layout
= 0;
6687 mddev
->new_level
= 4;
6688 return setup_conf(mddev
);
6690 return ERR_PTR(-EINVAL
);
6693 static struct md_personality raid5_personality
;
6695 static void *raid6_takeover(struct mddev
*mddev
)
6697 /* Currently can only take over a raid5. We map the
6698 * personality to an equivalent raid6 personality
6699 * with the Q block at the end.
6703 if (mddev
->pers
!= &raid5_personality
)
6704 return ERR_PTR(-EINVAL
);
6705 if (mddev
->degraded
> 1)
6706 return ERR_PTR(-EINVAL
);
6707 if (mddev
->raid_disks
> 253)
6708 return ERR_PTR(-EINVAL
);
6709 if (mddev
->raid_disks
< 3)
6710 return ERR_PTR(-EINVAL
);
6712 switch (mddev
->layout
) {
6713 case ALGORITHM_LEFT_ASYMMETRIC
:
6714 new_layout
= ALGORITHM_LEFT_ASYMMETRIC_6
;
6716 case ALGORITHM_RIGHT_ASYMMETRIC
:
6717 new_layout
= ALGORITHM_RIGHT_ASYMMETRIC_6
;
6719 case ALGORITHM_LEFT_SYMMETRIC
:
6720 new_layout
= ALGORITHM_LEFT_SYMMETRIC_6
;
6722 case ALGORITHM_RIGHT_SYMMETRIC
:
6723 new_layout
= ALGORITHM_RIGHT_SYMMETRIC_6
;
6725 case ALGORITHM_PARITY_0
:
6726 new_layout
= ALGORITHM_PARITY_0_6
;
6728 case ALGORITHM_PARITY_N
:
6729 new_layout
= ALGORITHM_PARITY_N
;
6732 return ERR_PTR(-EINVAL
);
6734 mddev
->new_level
= 6;
6735 mddev
->new_layout
= new_layout
;
6736 mddev
->delta_disks
= 1;
6737 mddev
->raid_disks
+= 1;
6738 return setup_conf(mddev
);
6742 static struct md_personality raid6_personality
=
6746 .owner
= THIS_MODULE
,
6747 .make_request
= make_request
,
6751 .error_handler
= error
,
6752 .hot_add_disk
= raid5_add_disk
,
6753 .hot_remove_disk
= raid5_remove_disk
,
6754 .spare_active
= raid5_spare_active
,
6755 .sync_request
= sync_request
,
6756 .resize
= raid5_resize
,
6758 .check_reshape
= raid6_check_reshape
,
6759 .start_reshape
= raid5_start_reshape
,
6760 .finish_reshape
= raid5_finish_reshape
,
6761 .quiesce
= raid5_quiesce
,
6762 .takeover
= raid6_takeover
,
6764 static struct md_personality raid5_personality
=
6768 .owner
= THIS_MODULE
,
6769 .make_request
= make_request
,
6773 .error_handler
= error
,
6774 .hot_add_disk
= raid5_add_disk
,
6775 .hot_remove_disk
= raid5_remove_disk
,
6776 .spare_active
= raid5_spare_active
,
6777 .sync_request
= sync_request
,
6778 .resize
= raid5_resize
,
6780 .check_reshape
= raid5_check_reshape
,
6781 .start_reshape
= raid5_start_reshape
,
6782 .finish_reshape
= raid5_finish_reshape
,
6783 .quiesce
= raid5_quiesce
,
6784 .takeover
= raid5_takeover
,
6787 static struct md_personality raid4_personality
=
6791 .owner
= THIS_MODULE
,
6792 .make_request
= make_request
,
6796 .error_handler
= error
,
6797 .hot_add_disk
= raid5_add_disk
,
6798 .hot_remove_disk
= raid5_remove_disk
,
6799 .spare_active
= raid5_spare_active
,
6800 .sync_request
= sync_request
,
6801 .resize
= raid5_resize
,
6803 .check_reshape
= raid5_check_reshape
,
6804 .start_reshape
= raid5_start_reshape
,
6805 .finish_reshape
= raid5_finish_reshape
,
6806 .quiesce
= raid5_quiesce
,
6807 .takeover
= raid4_takeover
,
6810 static int __init
raid5_init(void)
6812 raid5_wq
= alloc_workqueue("raid5wq",
6813 WQ_UNBOUND
|WQ_MEM_RECLAIM
|WQ_CPU_INTENSIVE
|WQ_SYSFS
, 0);
6816 register_md_personality(&raid6_personality
);
6817 register_md_personality(&raid5_personality
);
6818 register_md_personality(&raid4_personality
);
6822 static void raid5_exit(void)
6824 unregister_md_personality(&raid6_personality
);
6825 unregister_md_personality(&raid5_personality
);
6826 unregister_md_personality(&raid4_personality
);
6827 destroy_workqueue(raid5_wq
);
6830 module_init(raid5_init
);
6831 module_exit(raid5_exit
);
6832 MODULE_LICENSE("GPL");
6833 MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
6834 MODULE_ALIAS("md-personality-4"); /* RAID5 */
6835 MODULE_ALIAS("md-raid5");
6836 MODULE_ALIAS("md-raid4");
6837 MODULE_ALIAS("md-level-5");
6838 MODULE_ALIAS("md-level-4");
6839 MODULE_ALIAS("md-personality-8"); /* RAID6 */
6840 MODULE_ALIAS("md-raid6");
6841 MODULE_ALIAS("md-level-6");
6843 /* This used to be two separate modules, they were: */
6844 MODULE_ALIAS("raid5");
6845 MODULE_ALIAS("raid6");