2 * Copyright (C) 2012 Fusion-io All rights reserved.
3 * Copyright (C) 2012 Intel Corp. All rights reserved.
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public
7 * License v2 as published by the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
14 * You should have received a copy of the GNU General Public
15 * License along with this program; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 021110-1307, USA.
19 #include <linux/sched.h>
20 #include <linux/wait.h>
21 #include <linux/bio.h>
22 #include <linux/slab.h>
23 #include <linux/buffer_head.h>
24 #include <linux/blkdev.h>
25 #include <linux/random.h>
26 #include <linux/iocontext.h>
27 #include <linux/capability.h>
28 #include <linux/ratelimit.h>
29 #include <linux/kthread.h>
30 #include <linux/raid/pq.h>
31 #include <linux/hash.h>
32 #include <linux/list_sort.h>
33 #include <linux/raid/xor.h>
34 #include <asm/div64.h>
37 #include "extent_map.h"
39 #include "transaction.h"
40 #include "print-tree.h"
43 #include "async-thread.h"
44 #include "check-integrity.h"
45 #include "rcu-string.h"
47 /* set when additional merges to this rbio are not allowed */
48 #define RBIO_RMW_LOCKED_BIT 1
51 * set when this rbio is sitting in the hash, but it is just a cache
54 #define RBIO_CACHE_BIT 2
57 * set when it is safe to trust the stripe_pages for caching
59 #define RBIO_CACHE_READY_BIT 3
62 #define RBIO_CACHE_SIZE 1024
64 struct btrfs_raid_bio {
65 struct btrfs_fs_info *fs_info;
66 struct btrfs_bio *bbio;
69 * logical block numbers for the start of each stripe
70 * The last one or two are p/q. These are sorted,
71 * so raid_map[0] is the start of our full stripe
75 /* while we're doing rmw on a stripe
76 * we put it into a hash table so we can
77 * lock the stripe and merge more rbios
80 struct list_head hash_list;
83 * LRU list for the stripe cache
85 struct list_head stripe_cache;
88 * for scheduling work in the helper threads
90 struct btrfs_work work;
93 * bio list and bio_list_lock are used
94 * to add more bios into the stripe
95 * in hopes of avoiding the full rmw
97 struct bio_list bio_list;
98 spinlock_t bio_list_lock;
101 * also protected by the bio_list_lock, the
102 * stripe locking code uses plug_list to hand off
103 * the stripe lock to the next pending IO
105 struct list_head plug_list;
108 * flags that tell us if it is safe to
109 * merge with this bio
113 /* size of each individual stripe on disk */
116 /* number of data stripes (no p/q) */
120 * set if we're doing a parity rebuild
121 * for a read from higher up, which is handled
122 * differently from a parity rebuild as part of
127 /* first bad stripe */
130 /* second bad stripe (for raid6 use) */
134 * number of pages needed to represent the full
140 * size of all the bios in the bio_list. This
141 * helps us decide if the rbio maps to a full
149 * these are two arrays of pointers. We allocate the
150 * rbio big enough to hold them both and setup their
151 * locations when the rbio is allocated
154 /* pointers to pages that we allocated for
155 * reading/writing stripes directly from the disk (including P/Q)
157 struct page **stripe_pages;
160 * pointers to the pages in the bio_list. Stored
161 * here for faster lookup
163 struct page **bio_pages;
166 static int __raid56_parity_recover(struct btrfs_raid_bio *rbio);
167 static noinline void finish_rmw(struct btrfs_raid_bio *rbio);
168 static void rmw_work(struct btrfs_work *work);
169 static void read_rebuild_work(struct btrfs_work *work);
170 static void async_rmw_stripe(struct btrfs_raid_bio *rbio);
171 static void async_read_rebuild(struct btrfs_raid_bio *rbio);
172 static int fail_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio);
173 static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed);
174 static void __free_raid_bio(struct btrfs_raid_bio *rbio);
175 static void index_rbio_pages(struct btrfs_raid_bio *rbio);
176 static int alloc_rbio_pages(struct btrfs_raid_bio *rbio);
179 * the stripe hash table is used for locking, and to collect
180 * bios in hopes of making a full stripe
182 int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info)
184 struct btrfs_stripe_hash_table *table;
185 struct btrfs_stripe_hash_table *x;
186 struct btrfs_stripe_hash *cur;
187 struct btrfs_stripe_hash *h;
188 int num_entries = 1 << BTRFS_STRIPE_HASH_TABLE_BITS;
191 if (info->stripe_hash_table)
194 table = kzalloc(sizeof(*table) + sizeof(*h) * num_entries, GFP_NOFS);
198 spin_lock_init(&table->cache_lock);
199 INIT_LIST_HEAD(&table->stripe_cache);
203 for (i = 0; i < num_entries; i++) {
205 INIT_LIST_HEAD(&cur->hash_list);
206 spin_lock_init(&cur->lock);
207 init_waitqueue_head(&cur->wait);
210 x = cmpxchg(&info->stripe_hash_table, NULL, table);
217 * caching an rbio means to copy anything from the
218 * bio_pages array into the stripe_pages array. We
219 * use the page uptodate bit in the stripe cache array
220 * to indicate if it has valid data
222 * once the caching is done, we set the cache ready
225 static void cache_rbio_pages(struct btrfs_raid_bio *rbio)
232 ret = alloc_rbio_pages(rbio);
236 for (i = 0; i < rbio->nr_pages; i++) {
237 if (!rbio->bio_pages[i])
240 s = kmap(rbio->bio_pages[i]);
241 d = kmap(rbio->stripe_pages[i]);
243 memcpy(d, s, PAGE_CACHE_SIZE);
245 kunmap(rbio->bio_pages[i]);
246 kunmap(rbio->stripe_pages[i]);
247 SetPageUptodate(rbio->stripe_pages[i]);
249 set_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
253 * we hash on the first logical address of the stripe
255 static int rbio_bucket(struct btrfs_raid_bio *rbio)
257 u64 num = rbio->raid_map[0];
260 * we shift down quite a bit. We're using byte
261 * addressing, and most of the lower bits are zeros.
262 * This tends to upset hash_64, and it consistently
263 * returns just one or two different values.
265 * shifting off the lower bits fixes things.
267 return hash_64(num >> 16, BTRFS_STRIPE_HASH_TABLE_BITS);
271 * stealing an rbio means taking all the uptodate pages from the stripe
272 * array in the source rbio and putting them into the destination rbio
274 static void steal_rbio(struct btrfs_raid_bio *src, struct btrfs_raid_bio *dest)
280 if (!test_bit(RBIO_CACHE_READY_BIT, &src->flags))
283 for (i = 0; i < dest->nr_pages; i++) {
284 s = src->stripe_pages[i];
285 if (!s || !PageUptodate(s)) {
289 d = dest->stripe_pages[i];
293 dest->stripe_pages[i] = s;
294 src->stripe_pages[i] = NULL;
299 * merging means we take the bio_list from the victim and
300 * splice it into the destination. The victim should
301 * be discarded afterwards.
303 * must be called with dest->rbio_list_lock held
305 static void merge_rbio(struct btrfs_raid_bio *dest,
306 struct btrfs_raid_bio *victim)
308 bio_list_merge(&dest->bio_list, &victim->bio_list);
309 dest->bio_list_bytes += victim->bio_list_bytes;
310 bio_list_init(&victim->bio_list);
314 * used to prune items that are in the cache. The caller
315 * must hold the hash table lock.
317 static void __remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
319 int bucket = rbio_bucket(rbio);
320 struct btrfs_stripe_hash_table *table;
321 struct btrfs_stripe_hash *h;
325 * check the bit again under the hash table lock.
327 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
330 table = rbio->fs_info->stripe_hash_table;
331 h = table->table + bucket;
333 /* hold the lock for the bucket because we may be
334 * removing it from the hash table
339 * hold the lock for the bio list because we need
340 * to make sure the bio list is empty
342 spin_lock(&rbio->bio_list_lock);
344 if (test_and_clear_bit(RBIO_CACHE_BIT, &rbio->flags)) {
345 list_del_init(&rbio->stripe_cache);
346 table->cache_size -= 1;
349 /* if the bio list isn't empty, this rbio is
350 * still involved in an IO. We take it out
351 * of the cache list, and drop the ref that
352 * was held for the list.
354 * If the bio_list was empty, we also remove
355 * the rbio from the hash_table, and drop
356 * the corresponding ref
358 if (bio_list_empty(&rbio->bio_list)) {
359 if (!list_empty(&rbio->hash_list)) {
360 list_del_init(&rbio->hash_list);
361 atomic_dec(&rbio->refs);
362 BUG_ON(!list_empty(&rbio->plug_list));
367 spin_unlock(&rbio->bio_list_lock);
368 spin_unlock(&h->lock);
371 __free_raid_bio(rbio);
375 * prune a given rbio from the cache
377 static void remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
379 struct btrfs_stripe_hash_table *table;
382 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
385 table = rbio->fs_info->stripe_hash_table;
387 spin_lock_irqsave(&table->cache_lock, flags);
388 __remove_rbio_from_cache(rbio);
389 spin_unlock_irqrestore(&table->cache_lock, flags);
393 * remove everything in the cache
395 void btrfs_clear_rbio_cache(struct btrfs_fs_info *info)
397 struct btrfs_stripe_hash_table *table;
399 struct btrfs_raid_bio *rbio;
401 table = info->stripe_hash_table;
403 spin_lock_irqsave(&table->cache_lock, flags);
404 while (!list_empty(&table->stripe_cache)) {
405 rbio = list_entry(table->stripe_cache.next,
406 struct btrfs_raid_bio,
408 __remove_rbio_from_cache(rbio);
410 spin_unlock_irqrestore(&table->cache_lock, flags);
414 * remove all cached entries and free the hash table
417 void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info)
419 if (!info->stripe_hash_table)
421 btrfs_clear_rbio_cache(info);
422 kfree(info->stripe_hash_table);
423 info->stripe_hash_table = NULL;
427 * insert an rbio into the stripe cache. It
428 * must have already been prepared by calling
431 * If this rbio was already cached, it gets
432 * moved to the front of the lru.
434 * If the size of the rbio cache is too big, we
437 static void cache_rbio(struct btrfs_raid_bio *rbio)
439 struct btrfs_stripe_hash_table *table;
442 if (!test_bit(RBIO_CACHE_READY_BIT, &rbio->flags))
445 table = rbio->fs_info->stripe_hash_table;
447 spin_lock_irqsave(&table->cache_lock, flags);
448 spin_lock(&rbio->bio_list_lock);
450 /* bump our ref if we were not in the list before */
451 if (!test_and_set_bit(RBIO_CACHE_BIT, &rbio->flags))
452 atomic_inc(&rbio->refs);
454 if (!list_empty(&rbio->stripe_cache)){
455 list_move(&rbio->stripe_cache, &table->stripe_cache);
457 list_add(&rbio->stripe_cache, &table->stripe_cache);
458 table->cache_size += 1;
461 spin_unlock(&rbio->bio_list_lock);
463 if (table->cache_size > RBIO_CACHE_SIZE) {
464 struct btrfs_raid_bio *found;
466 found = list_entry(table->stripe_cache.prev,
467 struct btrfs_raid_bio,
471 __remove_rbio_from_cache(found);
474 spin_unlock_irqrestore(&table->cache_lock, flags);
479 * helper function to run the xor_blocks api. It is only
480 * able to do MAX_XOR_BLOCKS at a time, so we need to
483 static void run_xor(void **pages, int src_cnt, ssize_t len)
487 void *dest = pages[src_cnt];
490 xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS);
491 xor_blocks(xor_src_cnt, len, dest, pages + src_off);
493 src_cnt -= xor_src_cnt;
494 src_off += xor_src_cnt;
499 * returns true if the bio list inside this rbio
500 * covers an entire stripe (no rmw required).
501 * Must be called with the bio list lock held, or
502 * at a time when you know it is impossible to add
503 * new bios into the list
505 static int __rbio_is_full(struct btrfs_raid_bio *rbio)
507 unsigned long size = rbio->bio_list_bytes;
510 if (size != rbio->nr_data * rbio->stripe_len)
513 BUG_ON(size > rbio->nr_data * rbio->stripe_len);
517 static int rbio_is_full(struct btrfs_raid_bio *rbio)
522 spin_lock_irqsave(&rbio->bio_list_lock, flags);
523 ret = __rbio_is_full(rbio);
524 spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
529 * returns 1 if it is safe to merge two rbios together.
530 * The merging is safe if the two rbios correspond to
531 * the same stripe and if they are both going in the same
532 * direction (read vs write), and if neither one is
533 * locked for final IO
535 * The caller is responsible for locking such that
536 * rmw_locked is safe to test
538 static int rbio_can_merge(struct btrfs_raid_bio *last,
539 struct btrfs_raid_bio *cur)
541 if (test_bit(RBIO_RMW_LOCKED_BIT, &last->flags) ||
542 test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags))
546 * we can't merge with cached rbios, since the
547 * idea is that when we merge the destination
548 * rbio is going to run our IO for us. We can
549 * steal from cached rbio's though, other functions
552 if (test_bit(RBIO_CACHE_BIT, &last->flags) ||
553 test_bit(RBIO_CACHE_BIT, &cur->flags))
556 if (last->raid_map[0] !=
560 /* reads can't merge with writes */
561 if (last->read_rebuild !=
570 * helper to index into the pstripe
572 static struct page *rbio_pstripe_page(struct btrfs_raid_bio *rbio, int index)
574 index += (rbio->nr_data * rbio->stripe_len) >> PAGE_CACHE_SHIFT;
575 return rbio->stripe_pages[index];
579 * helper to index into the qstripe, returns null
580 * if there is no qstripe
582 static struct page *rbio_qstripe_page(struct btrfs_raid_bio *rbio, int index)
584 if (rbio->nr_data + 1 == rbio->bbio->num_stripes)
587 index += ((rbio->nr_data + 1) * rbio->stripe_len) >>
589 return rbio->stripe_pages[index];
593 * The first stripe in the table for a logical address
594 * has the lock. rbios are added in one of three ways:
596 * 1) Nobody has the stripe locked yet. The rbio is given
597 * the lock and 0 is returned. The caller must start the IO
600 * 2) Someone has the stripe locked, but we're able to merge
601 * with the lock owner. The rbio is freed and the IO will
602 * start automatically along with the existing rbio. 1 is returned.
604 * 3) Someone has the stripe locked, but we're not able to merge.
605 * The rbio is added to the lock owner's plug list, or merged into
606 * an rbio already on the plug list. When the lock owner unlocks,
607 * the next rbio on the list is run and the IO is started automatically.
610 * If we return 0, the caller still owns the rbio and must continue with
611 * IO submission. If we return 1, the caller must assume the rbio has
612 * already been freed.
614 static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
616 int bucket = rbio_bucket(rbio);
617 struct btrfs_stripe_hash *h = rbio->fs_info->stripe_hash_table->table + bucket;
618 struct btrfs_raid_bio *cur;
619 struct btrfs_raid_bio *pending;
622 struct btrfs_raid_bio *freeit = NULL;
623 struct btrfs_raid_bio *cache_drop = NULL;
627 spin_lock_irqsave(&h->lock, flags);
628 list_for_each_entry(cur, &h->hash_list, hash_list) {
630 if (cur->raid_map[0] == rbio->raid_map[0]) {
631 spin_lock(&cur->bio_list_lock);
633 /* can we steal this cached rbio's pages? */
634 if (bio_list_empty(&cur->bio_list) &&
635 list_empty(&cur->plug_list) &&
636 test_bit(RBIO_CACHE_BIT, &cur->flags) &&
637 !test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) {
638 list_del_init(&cur->hash_list);
639 atomic_dec(&cur->refs);
641 steal_rbio(cur, rbio);
643 spin_unlock(&cur->bio_list_lock);
648 /* can we merge into the lock owner? */
649 if (rbio_can_merge(cur, rbio)) {
650 merge_rbio(cur, rbio);
651 spin_unlock(&cur->bio_list_lock);
659 * we couldn't merge with the running
660 * rbio, see if we can merge with the
661 * pending ones. We don't have to
662 * check for rmw_locked because there
663 * is no way they are inside finish_rmw
666 list_for_each_entry(pending, &cur->plug_list,
668 if (rbio_can_merge(pending, rbio)) {
669 merge_rbio(pending, rbio);
670 spin_unlock(&cur->bio_list_lock);
677 /* no merging, put us on the tail of the plug list,
678 * our rbio will be started with the currently
679 * running rbio unlocks
681 list_add_tail(&rbio->plug_list, &cur->plug_list);
682 spin_unlock(&cur->bio_list_lock);
688 atomic_inc(&rbio->refs);
689 list_add(&rbio->hash_list, &h->hash_list);
691 spin_unlock_irqrestore(&h->lock, flags);
693 remove_rbio_from_cache(cache_drop);
695 __free_raid_bio(freeit);
700 * called as rmw or parity rebuild is completed. If the plug list has more
701 * rbios waiting for this stripe, the next one on the list will be started
703 static noinline void unlock_stripe(struct btrfs_raid_bio *rbio)
706 struct btrfs_stripe_hash *h;
710 bucket = rbio_bucket(rbio);
711 h = rbio->fs_info->stripe_hash_table->table + bucket;
713 if (list_empty(&rbio->plug_list))
716 spin_lock_irqsave(&h->lock, flags);
717 spin_lock(&rbio->bio_list_lock);
719 if (!list_empty(&rbio->hash_list)) {
721 * if we're still cached and there is no other IO
722 * to perform, just leave this rbio here for others
723 * to steal from later
725 if (list_empty(&rbio->plug_list) &&
726 test_bit(RBIO_CACHE_BIT, &rbio->flags)) {
728 clear_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
729 BUG_ON(!bio_list_empty(&rbio->bio_list));
733 list_del_init(&rbio->hash_list);
734 atomic_dec(&rbio->refs);
737 * we use the plug list to hold all the rbios
738 * waiting for the chance to lock this stripe.
739 * hand the lock over to one of them.
741 if (!list_empty(&rbio->plug_list)) {
742 struct btrfs_raid_bio *next;
743 struct list_head *head = rbio->plug_list.next;
745 next = list_entry(head, struct btrfs_raid_bio,
748 list_del_init(&rbio->plug_list);
750 list_add(&next->hash_list, &h->hash_list);
751 atomic_inc(&next->refs);
752 spin_unlock(&rbio->bio_list_lock);
753 spin_unlock_irqrestore(&h->lock, flags);
755 if (next->read_rebuild)
756 async_read_rebuild(next);
758 steal_rbio(rbio, next);
759 async_rmw_stripe(next);
763 } else if (waitqueue_active(&h->wait)) {
764 spin_unlock(&rbio->bio_list_lock);
765 spin_unlock_irqrestore(&h->lock, flags);
771 spin_unlock(&rbio->bio_list_lock);
772 spin_unlock_irqrestore(&h->lock, flags);
776 remove_rbio_from_cache(rbio);
779 static void __free_raid_bio(struct btrfs_raid_bio *rbio)
783 WARN_ON(atomic_read(&rbio->refs) < 0);
784 if (!atomic_dec_and_test(&rbio->refs))
787 WARN_ON(!list_empty(&rbio->stripe_cache));
788 WARN_ON(!list_empty(&rbio->hash_list));
789 WARN_ON(!bio_list_empty(&rbio->bio_list));
791 for (i = 0; i < rbio->nr_pages; i++) {
792 if (rbio->stripe_pages[i]) {
793 __free_page(rbio->stripe_pages[i]);
794 rbio->stripe_pages[i] = NULL;
797 kfree(rbio->raid_map);
802 static void free_raid_bio(struct btrfs_raid_bio *rbio)
805 __free_raid_bio(rbio);
809 * this frees the rbio and runs through all the bios in the
810 * bio_list and calls end_io on them
812 static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, int err, int uptodate)
814 struct bio *cur = bio_list_get(&rbio->bio_list);
822 set_bit(BIO_UPTODATE, &cur->bi_flags);
829 * end io function used by finish_rmw. When we finally
830 * get here, we've written a full stripe
832 static void raid_write_end_io(struct bio *bio, int err)
834 struct btrfs_raid_bio *rbio = bio->bi_private;
837 fail_bio_stripe(rbio, bio);
841 if (!atomic_dec_and_test(&rbio->bbio->stripes_pending))
846 /* OK, we have read all the stripes we need to. */
847 if (atomic_read(&rbio->bbio->error) > rbio->bbio->max_errors)
850 rbio_orig_end_io(rbio, err, 0);
855 * the read/modify/write code wants to use the original bio for
856 * any pages it included, and then use the rbio for everything
857 * else. This function decides if a given index (stripe number)
858 * and page number in that stripe fall inside the original bio
861 * if you set bio_list_only, you'll get a NULL back for any ranges
862 * that are outside the bio_list
864 * This doesn't take any refs on anything, you get a bare page pointer
865 * and the caller must bump refs as required.
867 * You must call index_rbio_pages once before you can trust
868 * the answers from this function.
870 static struct page *page_in_rbio(struct btrfs_raid_bio *rbio,
871 int index, int pagenr, int bio_list_only)
874 struct page *p = NULL;
876 chunk_page = index * (rbio->stripe_len >> PAGE_SHIFT) + pagenr;
878 spin_lock_irq(&rbio->bio_list_lock);
879 p = rbio->bio_pages[chunk_page];
880 spin_unlock_irq(&rbio->bio_list_lock);
882 if (p || bio_list_only)
885 return rbio->stripe_pages[chunk_page];
889 * number of pages we need for the entire stripe across all the
892 static unsigned long rbio_nr_pages(unsigned long stripe_len, int nr_stripes)
894 unsigned long nr = stripe_len * nr_stripes;
895 return (nr + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
899 * allocation and initial setup for the btrfs_raid_bio. Not
900 * this does not allocate any pages for rbio->pages.
902 static struct btrfs_raid_bio *alloc_rbio(struct btrfs_root *root,
903 struct btrfs_bio *bbio, u64 *raid_map,
906 struct btrfs_raid_bio *rbio;
908 int num_pages = rbio_nr_pages(stripe_len, bbio->num_stripes);
911 rbio = kzalloc(sizeof(*rbio) + num_pages * sizeof(struct page *) * 2,
916 return ERR_PTR(-ENOMEM);
919 bio_list_init(&rbio->bio_list);
920 INIT_LIST_HEAD(&rbio->plug_list);
921 spin_lock_init(&rbio->bio_list_lock);
922 INIT_LIST_HEAD(&rbio->stripe_cache);
923 INIT_LIST_HEAD(&rbio->hash_list);
925 rbio->raid_map = raid_map;
926 rbio->fs_info = root->fs_info;
927 rbio->stripe_len = stripe_len;
928 rbio->nr_pages = num_pages;
931 atomic_set(&rbio->refs, 1);
934 * the stripe_pages and bio_pages array point to the extra
935 * memory we allocated past the end of the rbio
938 rbio->stripe_pages = p;
939 rbio->bio_pages = p + sizeof(struct page *) * num_pages;
941 if (raid_map[bbio->num_stripes - 1] == RAID6_Q_STRIPE)
942 nr_data = bbio->num_stripes - 2;
944 nr_data = bbio->num_stripes - 1;
946 rbio->nr_data = nr_data;
950 /* allocate pages for all the stripes in the bio, including parity */
951 static int alloc_rbio_pages(struct btrfs_raid_bio *rbio)
956 for (i = 0; i < rbio->nr_pages; i++) {
957 if (rbio->stripe_pages[i])
959 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
962 rbio->stripe_pages[i] = page;
963 ClearPageUptodate(page);
968 /* allocate pages for just the p/q stripes */
969 static int alloc_rbio_parity_pages(struct btrfs_raid_bio *rbio)
974 i = (rbio->nr_data * rbio->stripe_len) >> PAGE_CACHE_SHIFT;
976 for (; i < rbio->nr_pages; i++) {
977 if (rbio->stripe_pages[i])
979 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
982 rbio->stripe_pages[i] = page;
988 * add a single page from a specific stripe into our list of bios for IO
989 * this will try to merge into existing bios if possible, and returns
990 * zero if all went well.
992 int rbio_add_io_page(struct btrfs_raid_bio *rbio,
993 struct bio_list *bio_list,
996 unsigned long page_index,
997 unsigned long bio_max_len)
999 struct bio *last = bio_list->tail;
1003 struct btrfs_bio_stripe *stripe;
1006 stripe = &rbio->bbio->stripes[stripe_nr];
1007 disk_start = stripe->physical + (page_index << PAGE_CACHE_SHIFT);
1009 /* if the device is missing, just fail this stripe */
1010 if (!stripe->dev->bdev)
1011 return fail_rbio_index(rbio, stripe_nr);
1013 /* see if we can add this page onto our existing bio */
1015 last_end = (u64)last->bi_sector << 9;
1016 last_end += last->bi_size;
1019 * we can't merge these if they are from different
1020 * devices or if they are not contiguous
1022 if (last_end == disk_start && stripe->dev->bdev &&
1023 test_bit(BIO_UPTODATE, &last->bi_flags) &&
1024 last->bi_bdev == stripe->dev->bdev) {
1025 ret = bio_add_page(last, page, PAGE_CACHE_SIZE, 0);
1026 if (ret == PAGE_CACHE_SIZE)
1031 /* put a new bio on the list */
1032 bio = bio_alloc(GFP_NOFS, bio_max_len >> PAGE_SHIFT?:1);
1037 bio->bi_bdev = stripe->dev->bdev;
1038 bio->bi_sector = disk_start >> 9;
1039 set_bit(BIO_UPTODATE, &bio->bi_flags);
1041 bio_add_page(bio, page, PAGE_CACHE_SIZE, 0);
1042 bio_list_add(bio_list, bio);
1047 * while we're doing the read/modify/write cycle, we could
1048 * have errors in reading pages off the disk. This checks
1049 * for errors and if we're not able to read the page it'll
1050 * trigger parity reconstruction. The rmw will be finished
1051 * after we've reconstructed the failed stripes
1053 static void validate_rbio_for_rmw(struct btrfs_raid_bio *rbio)
1055 if (rbio->faila >= 0 || rbio->failb >= 0) {
1056 BUG_ON(rbio->faila == rbio->bbio->num_stripes - 1);
1057 __raid56_parity_recover(rbio);
1064 * these are just the pages from the rbio array, not from anything
1065 * the FS sent down to us
1067 static struct page *rbio_stripe_page(struct btrfs_raid_bio *rbio, int stripe, int page)
1070 index = stripe * (rbio->stripe_len >> PAGE_CACHE_SHIFT);
1072 return rbio->stripe_pages[index];
1076 * helper function to walk our bio list and populate the bio_pages array with
1077 * the result. This seems expensive, but it is faster than constantly
1078 * searching through the bio list as we setup the IO in finish_rmw or stripe
1081 * This must be called before you trust the answers from page_in_rbio
1083 static void index_rbio_pages(struct btrfs_raid_bio *rbio)
1087 unsigned long stripe_offset;
1088 unsigned long page_index;
1092 spin_lock_irq(&rbio->bio_list_lock);
1093 bio_list_for_each(bio, &rbio->bio_list) {
1094 start = (u64)bio->bi_sector << 9;
1095 stripe_offset = start - rbio->raid_map[0];
1096 page_index = stripe_offset >> PAGE_CACHE_SHIFT;
1098 for (i = 0; i < bio->bi_vcnt; i++) {
1099 p = bio->bi_io_vec[i].bv_page;
1100 rbio->bio_pages[page_index + i] = p;
1103 spin_unlock_irq(&rbio->bio_list_lock);
1107 * this is called from one of two situations. We either
1108 * have a full stripe from the higher layers, or we've read all
1109 * the missing bits off disk.
1111 * This will calculate the parity and then send down any
1114 static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
1116 struct btrfs_bio *bbio = rbio->bbio;
1117 void *pointers[bbio->num_stripes];
1118 int stripe_len = rbio->stripe_len;
1119 int nr_data = rbio->nr_data;
1124 struct bio_list bio_list;
1126 int pages_per_stripe = stripe_len >> PAGE_CACHE_SHIFT;
1129 bio_list_init(&bio_list);
1131 if (bbio->num_stripes - rbio->nr_data == 1) {
1132 p_stripe = bbio->num_stripes - 1;
1133 } else if (bbio->num_stripes - rbio->nr_data == 2) {
1134 p_stripe = bbio->num_stripes - 2;
1135 q_stripe = bbio->num_stripes - 1;
1140 /* at this point we either have a full stripe,
1141 * or we've read the full stripe from the drive.
1142 * recalculate the parity and write the new results.
1144 * We're not allowed to add any new bios to the
1145 * bio list here, anyone else that wants to
1146 * change this stripe needs to do their own rmw.
1148 spin_lock_irq(&rbio->bio_list_lock);
1149 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1150 spin_unlock_irq(&rbio->bio_list_lock);
1152 atomic_set(&rbio->bbio->error, 0);
1155 * now that we've set rmw_locked, run through the
1156 * bio list one last time and map the page pointers
1158 * We don't cache full rbios because we're assuming
1159 * the higher layers are unlikely to use this area of
1160 * the disk again soon. If they do use it again,
1161 * hopefully they will send another full bio.
1163 index_rbio_pages(rbio);
1164 if (!rbio_is_full(rbio))
1165 cache_rbio_pages(rbio);
1167 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
1169 for (pagenr = 0; pagenr < pages_per_stripe; pagenr++) {
1171 /* first collect one page from each data stripe */
1172 for (stripe = 0; stripe < nr_data; stripe++) {
1173 p = page_in_rbio(rbio, stripe, pagenr, 0);
1174 pointers[stripe] = kmap(p);
1177 /* then add the parity stripe */
1178 p = rbio_pstripe_page(rbio, pagenr);
1180 pointers[stripe++] = kmap(p);
1182 if (q_stripe != -1) {
1185 * raid6, add the qstripe and call the
1186 * library function to fill in our p/q
1188 p = rbio_qstripe_page(rbio, pagenr);
1190 pointers[stripe++] = kmap(p);
1192 raid6_call.gen_syndrome(bbio->num_stripes, PAGE_SIZE,
1196 memcpy(pointers[nr_data], pointers[0], PAGE_SIZE);
1197 run_xor(pointers + 1, nr_data - 1, PAGE_CACHE_SIZE);
1201 for (stripe = 0; stripe < bbio->num_stripes; stripe++)
1202 kunmap(page_in_rbio(rbio, stripe, pagenr, 0));
1206 * time to start writing. Make bios for everything from the
1207 * higher layers (the bio_list in our rbio) and our p/q. Ignore
1210 for (stripe = 0; stripe < bbio->num_stripes; stripe++) {
1211 for (pagenr = 0; pagenr < pages_per_stripe; pagenr++) {
1213 if (stripe < rbio->nr_data) {
1214 page = page_in_rbio(rbio, stripe, pagenr, 1);
1218 page = rbio_stripe_page(rbio, stripe, pagenr);
1221 ret = rbio_add_io_page(rbio, &bio_list,
1222 page, stripe, pagenr, rbio->stripe_len);
1228 atomic_set(&bbio->stripes_pending, bio_list_size(&bio_list));
1229 BUG_ON(atomic_read(&bbio->stripes_pending) == 0);
1232 bio = bio_list_pop(&bio_list);
1236 bio->bi_private = rbio;
1237 bio->bi_end_io = raid_write_end_io;
1238 BUG_ON(!test_bit(BIO_UPTODATE, &bio->bi_flags));
1239 submit_bio(WRITE, bio);
1244 rbio_orig_end_io(rbio, -EIO, 0);
1248 * helper to find the stripe number for a given bio. Used to figure out which
1249 * stripe has failed. This expects the bio to correspond to a physical disk,
1250 * so it looks up based on physical sector numbers.
1252 static int find_bio_stripe(struct btrfs_raid_bio *rbio,
1255 u64 physical = bio->bi_sector;
1258 struct btrfs_bio_stripe *stripe;
1262 for (i = 0; i < rbio->bbio->num_stripes; i++) {
1263 stripe = &rbio->bbio->stripes[i];
1264 stripe_start = stripe->physical;
1265 if (physical >= stripe_start &&
1266 physical < stripe_start + rbio->stripe_len) {
1274 * helper to find the stripe number for a given
1275 * bio (before mapping). Used to figure out which stripe has
1276 * failed. This looks up based on logical block numbers.
1278 static int find_logical_bio_stripe(struct btrfs_raid_bio *rbio,
1281 u64 logical = bio->bi_sector;
1287 for (i = 0; i < rbio->nr_data; i++) {
1288 stripe_start = rbio->raid_map[i];
1289 if (logical >= stripe_start &&
1290 logical < stripe_start + rbio->stripe_len) {
1298 * returns -EIO if we had too many failures
1300 static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed)
1302 unsigned long flags;
1305 spin_lock_irqsave(&rbio->bio_list_lock, flags);
1307 /* we already know this stripe is bad, move on */
1308 if (rbio->faila == failed || rbio->failb == failed)
1311 if (rbio->faila == -1) {
1312 /* first failure on this rbio */
1313 rbio->faila = failed;
1314 atomic_inc(&rbio->bbio->error);
1315 } else if (rbio->failb == -1) {
1316 /* second failure on this rbio */
1317 rbio->failb = failed;
1318 atomic_inc(&rbio->bbio->error);
1323 spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
1329 * helper to fail a stripe based on a physical disk
1332 static int fail_bio_stripe(struct btrfs_raid_bio *rbio,
1335 int failed = find_bio_stripe(rbio, bio);
1340 return fail_rbio_index(rbio, failed);
1344 * this sets each page in the bio uptodate. It should only be used on private
1345 * rbio pages, nothing that comes in from the higher layers
1347 static void set_bio_pages_uptodate(struct bio *bio)
1352 for (i = 0; i < bio->bi_vcnt; i++) {
1353 p = bio->bi_io_vec[i].bv_page;
1359 * end io for the read phase of the rmw cycle. All the bios here are physical
1360 * stripe bios we've read from the disk so we can recalculate the parity of the
1363 * This will usually kick off finish_rmw once all the bios are read in, but it
1364 * may trigger parity reconstruction if we had any errors along the way
1366 static void raid_rmw_end_io(struct bio *bio, int err)
1368 struct btrfs_raid_bio *rbio = bio->bi_private;
1371 fail_bio_stripe(rbio, bio);
1373 set_bio_pages_uptodate(bio);
1377 if (!atomic_dec_and_test(&rbio->bbio->stripes_pending))
1381 if (atomic_read(&rbio->bbio->error) > rbio->bbio->max_errors)
1385 * this will normally call finish_rmw to start our write
1386 * but if there are any failed stripes we'll reconstruct
1389 validate_rbio_for_rmw(rbio);
1394 rbio_orig_end_io(rbio, -EIO, 0);
1397 static void async_rmw_stripe(struct btrfs_raid_bio *rbio)
1399 rbio->work.flags = 0;
1400 rbio->work.func = rmw_work;
1402 btrfs_queue_worker(&rbio->fs_info->rmw_workers,
1406 static void async_read_rebuild(struct btrfs_raid_bio *rbio)
1408 rbio->work.flags = 0;
1409 rbio->work.func = read_rebuild_work;
1411 btrfs_queue_worker(&rbio->fs_info->rmw_workers,
1416 * the stripe must be locked by the caller. It will
1417 * unlock after all the writes are done
1419 static int raid56_rmw_stripe(struct btrfs_raid_bio *rbio)
1421 int bios_to_read = 0;
1422 struct btrfs_bio *bbio = rbio->bbio;
1423 struct bio_list bio_list;
1425 int nr_pages = (rbio->stripe_len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1430 bio_list_init(&bio_list);
1432 ret = alloc_rbio_pages(rbio);
1436 index_rbio_pages(rbio);
1438 atomic_set(&rbio->bbio->error, 0);
1440 * build a list of bios to read all the missing parts of this
1443 for (stripe = 0; stripe < rbio->nr_data; stripe++) {
1444 for (pagenr = 0; pagenr < nr_pages; pagenr++) {
1447 * we want to find all the pages missing from
1448 * the rbio and read them from the disk. If
1449 * page_in_rbio finds a page in the bio list
1450 * we don't need to read it off the stripe.
1452 page = page_in_rbio(rbio, stripe, pagenr, 1);
1456 page = rbio_stripe_page(rbio, stripe, pagenr);
1458 * the bio cache may have handed us an uptodate
1459 * page. If so, be happy and use it
1461 if (PageUptodate(page))
1464 ret = rbio_add_io_page(rbio, &bio_list, page,
1465 stripe, pagenr, rbio->stripe_len);
1471 bios_to_read = bio_list_size(&bio_list);
1472 if (!bios_to_read) {
1474 * this can happen if others have merged with
1475 * us, it means there is nothing left to read.
1476 * But if there are missing devices it may not be
1477 * safe to do the full stripe write yet.
1483 * the bbio may be freed once we submit the last bio. Make sure
1484 * not to touch it after that
1486 atomic_set(&bbio->stripes_pending, bios_to_read);
1488 bio = bio_list_pop(&bio_list);
1492 bio->bi_private = rbio;
1493 bio->bi_end_io = raid_rmw_end_io;
1495 btrfs_bio_wq_end_io(rbio->fs_info, bio,
1496 BTRFS_WQ_ENDIO_RAID56);
1498 BUG_ON(!test_bit(BIO_UPTODATE, &bio->bi_flags));
1499 submit_bio(READ, bio);
1501 /* the actual write will happen once the reads are done */
1505 rbio_orig_end_io(rbio, -EIO, 0);
1509 validate_rbio_for_rmw(rbio);
1514 * if the upper layers pass in a full stripe, we thank them by only allocating
1515 * enough pages to hold the parity, and sending it all down quickly.
1517 static int full_stripe_write(struct btrfs_raid_bio *rbio)
1521 ret = alloc_rbio_parity_pages(rbio);
1525 ret = lock_stripe_add(rbio);
1532 * partial stripe writes get handed over to async helpers.
1533 * We're really hoping to merge a few more writes into this
1534 * rbio before calculating new parity
1536 static int partial_stripe_write(struct btrfs_raid_bio *rbio)
1540 ret = lock_stripe_add(rbio);
1542 async_rmw_stripe(rbio);
1547 * sometimes while we were reading from the drive to
1548 * recalculate parity, enough new bios come into create
1549 * a full stripe. So we do a check here to see if we can
1550 * go directly to finish_rmw
1552 static int __raid56_parity_write(struct btrfs_raid_bio *rbio)
1554 /* head off into rmw land if we don't have a full stripe */
1555 if (!rbio_is_full(rbio))
1556 return partial_stripe_write(rbio);
1557 return full_stripe_write(rbio);
1561 * our main entry point for writes from the rest of the FS.
1563 int raid56_parity_write(struct btrfs_root *root, struct bio *bio,
1564 struct btrfs_bio *bbio, u64 *raid_map,
1567 struct btrfs_raid_bio *rbio;
1569 rbio = alloc_rbio(root, bbio, raid_map, stripe_len);
1573 return PTR_ERR(rbio);
1575 bio_list_add(&rbio->bio_list, bio);
1576 rbio->bio_list_bytes = bio->bi_size;
1577 return __raid56_parity_write(rbio);
1581 * all parity reconstruction happens here. We've read in everything
1582 * we can find from the drives and this does the heavy lifting of
1583 * sorting the good from the bad.
1585 static void __raid_recover_end_io(struct btrfs_raid_bio *rbio)
1589 int faila = -1, failb = -1;
1590 int nr_pages = (rbio->stripe_len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1595 pointers = kzalloc(rbio->bbio->num_stripes * sizeof(void *),
1602 faila = rbio->faila;
1603 failb = rbio->failb;
1605 if (rbio->read_rebuild) {
1606 spin_lock_irq(&rbio->bio_list_lock);
1607 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1608 spin_unlock_irq(&rbio->bio_list_lock);
1611 index_rbio_pages(rbio);
1613 for (pagenr = 0; pagenr < nr_pages; pagenr++) {
1614 /* setup our array of pointers with pages
1617 for (stripe = 0; stripe < rbio->bbio->num_stripes; stripe++) {
1619 * if we're rebuilding a read, we have to use
1620 * pages from the bio list
1622 if (rbio->read_rebuild &&
1623 (stripe == faila || stripe == failb)) {
1624 page = page_in_rbio(rbio, stripe, pagenr, 0);
1626 page = rbio_stripe_page(rbio, stripe, pagenr);
1628 pointers[stripe] = kmap(page);
1631 /* all raid6 handling here */
1632 if (rbio->raid_map[rbio->bbio->num_stripes - 1] ==
1636 * single failure, rebuild from parity raid5
1640 if (faila == rbio->nr_data) {
1642 * Just the P stripe has failed, without
1643 * a bad data or Q stripe.
1644 * TODO, we should redo the xor here.
1650 * a single failure in raid6 is rebuilt
1651 * in the pstripe code below
1656 /* make sure our ps and qs are in order */
1657 if (faila > failb) {
1663 /* if the q stripe is failed, do a pstripe reconstruction
1665 * If both the q stripe and the P stripe are failed, we're
1666 * here due to a crc mismatch and we can't give them the
1669 if (rbio->raid_map[failb] == RAID6_Q_STRIPE) {
1670 if (rbio->raid_map[faila] == RAID5_P_STRIPE) {
1675 * otherwise we have one bad data stripe and
1676 * a good P stripe. raid5!
1681 if (rbio->raid_map[failb] == RAID5_P_STRIPE) {
1682 raid6_datap_recov(rbio->bbio->num_stripes,
1683 PAGE_SIZE, faila, pointers);
1685 raid6_2data_recov(rbio->bbio->num_stripes,
1686 PAGE_SIZE, faila, failb,
1692 /* rebuild from P stripe here (raid5 or raid6) */
1693 BUG_ON(failb != -1);
1695 /* Copy parity block into failed block to start with */
1696 memcpy(pointers[faila],
1697 pointers[rbio->nr_data],
1700 /* rearrange the pointer array */
1701 p = pointers[faila];
1702 for (stripe = faila; stripe < rbio->nr_data - 1; stripe++)
1703 pointers[stripe] = pointers[stripe + 1];
1704 pointers[rbio->nr_data - 1] = p;
1706 /* xor in the rest */
1707 run_xor(pointers, rbio->nr_data - 1, PAGE_CACHE_SIZE);
1709 /* if we're doing this rebuild as part of an rmw, go through
1710 * and set all of our private rbio pages in the
1711 * failed stripes as uptodate. This way finish_rmw will
1712 * know they can be trusted. If this was a read reconstruction,
1713 * other endio functions will fiddle the uptodate bits
1715 if (!rbio->read_rebuild) {
1716 for (i = 0; i < nr_pages; i++) {
1718 page = rbio_stripe_page(rbio, faila, i);
1719 SetPageUptodate(page);
1722 page = rbio_stripe_page(rbio, failb, i);
1723 SetPageUptodate(page);
1727 for (stripe = 0; stripe < rbio->bbio->num_stripes; stripe++) {
1729 * if we're rebuilding a read, we have to use
1730 * pages from the bio list
1732 if (rbio->read_rebuild &&
1733 (stripe == faila || stripe == failb)) {
1734 page = page_in_rbio(rbio, stripe, pagenr, 0);
1736 page = rbio_stripe_page(rbio, stripe, pagenr);
1748 if (rbio->read_rebuild) {
1750 cache_rbio_pages(rbio);
1752 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
1754 rbio_orig_end_io(rbio, err, err == 0);
1755 } else if (err == 0) {
1760 rbio_orig_end_io(rbio, err, 0);
1765 * This is called only for stripes we've read from disk to
1766 * reconstruct the parity.
1768 static void raid_recover_end_io(struct bio *bio, int err)
1770 struct btrfs_raid_bio *rbio = bio->bi_private;
1773 * we only read stripe pages off the disk, set them
1774 * up to date if there were no errors
1777 fail_bio_stripe(rbio, bio);
1779 set_bio_pages_uptodate(bio);
1782 if (!atomic_dec_and_test(&rbio->bbio->stripes_pending))
1785 if (atomic_read(&rbio->bbio->error) > rbio->bbio->max_errors)
1786 rbio_orig_end_io(rbio, -EIO, 0);
1788 __raid_recover_end_io(rbio);
1792 * reads everything we need off the disk to reconstruct
1793 * the parity. endio handlers trigger final reconstruction
1794 * when the IO is done.
1796 * This is used both for reads from the higher layers and for
1797 * parity construction required to finish a rmw cycle.
1799 static int __raid56_parity_recover(struct btrfs_raid_bio *rbio)
1801 int bios_to_read = 0;
1802 struct btrfs_bio *bbio = rbio->bbio;
1803 struct bio_list bio_list;
1805 int nr_pages = (rbio->stripe_len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1810 bio_list_init(&bio_list);
1812 ret = alloc_rbio_pages(rbio);
1816 atomic_set(&rbio->bbio->error, 0);
1819 * read everything that hasn't failed. Thanks to the
1820 * stripe cache, it is possible that some or all of these
1821 * pages are going to be uptodate.
1823 for (stripe = 0; stripe < bbio->num_stripes; stripe++) {
1824 if (rbio->faila == stripe ||
1825 rbio->failb == stripe)
1828 for (pagenr = 0; pagenr < nr_pages; pagenr++) {
1832 * the rmw code may have already read this
1835 p = rbio_stripe_page(rbio, stripe, pagenr);
1836 if (PageUptodate(p))
1839 ret = rbio_add_io_page(rbio, &bio_list,
1840 rbio_stripe_page(rbio, stripe, pagenr),
1841 stripe, pagenr, rbio->stripe_len);
1847 bios_to_read = bio_list_size(&bio_list);
1848 if (!bios_to_read) {
1850 * we might have no bios to read just because the pages
1851 * were up to date, or we might have no bios to read because
1852 * the devices were gone.
1854 if (atomic_read(&rbio->bbio->error) <= rbio->bbio->max_errors) {
1855 __raid_recover_end_io(rbio);
1863 * the bbio may be freed once we submit the last bio. Make sure
1864 * not to touch it after that
1866 atomic_set(&bbio->stripes_pending, bios_to_read);
1868 bio = bio_list_pop(&bio_list);
1872 bio->bi_private = rbio;
1873 bio->bi_end_io = raid_recover_end_io;
1875 btrfs_bio_wq_end_io(rbio->fs_info, bio,
1876 BTRFS_WQ_ENDIO_RAID56);
1878 BUG_ON(!test_bit(BIO_UPTODATE, &bio->bi_flags));
1879 submit_bio(READ, bio);
1885 if (rbio->read_rebuild)
1886 rbio_orig_end_io(rbio, -EIO, 0);
1891 * the main entry point for reads from the higher layers. This
1892 * is really only called when the normal read path had a failure,
1893 * so we assume the bio they send down corresponds to a failed part
1896 int raid56_parity_recover(struct btrfs_root *root, struct bio *bio,
1897 struct btrfs_bio *bbio, u64 *raid_map,
1898 u64 stripe_len, int mirror_num)
1900 struct btrfs_raid_bio *rbio;
1903 rbio = alloc_rbio(root, bbio, raid_map, stripe_len);
1905 return PTR_ERR(rbio);
1908 rbio->read_rebuild = 1;
1909 bio_list_add(&rbio->bio_list, bio);
1910 rbio->bio_list_bytes = bio->bi_size;
1912 rbio->faila = find_logical_bio_stripe(rbio, bio);
1913 if (rbio->faila == -1) {
1920 * reconstruct from the q stripe if they are
1921 * asking for mirror 3
1923 if (mirror_num == 3)
1924 rbio->failb = bbio->num_stripes - 2;
1926 ret = lock_stripe_add(rbio);
1929 * __raid56_parity_recover will end the bio with
1930 * any errors it hits. We don't want to return
1931 * its error value up the stack because our caller
1932 * will end up calling bio_endio with any nonzero
1936 __raid56_parity_recover(rbio);
1938 * our rbio has been added to the list of
1939 * rbios that will be handled after the
1940 * currently lock owner is done
1946 static void rmw_work(struct btrfs_work *work)
1948 struct btrfs_raid_bio *rbio;
1950 rbio = container_of(work, struct btrfs_raid_bio, work);
1951 raid56_rmw_stripe(rbio);
1954 static void read_rebuild_work(struct btrfs_work *work)
1956 struct btrfs_raid_bio *rbio;
1958 rbio = container_of(work, struct btrfs_raid_bio, work);
1959 __raid56_parity_recover(rbio);