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1/*
2 * Copyright (C) 2012 Fusion-io All rights reserved.
3 * Copyright (C) 2012 Intel Corp. All rights reserved.
4 *
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.
8 *
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.
13 *
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.
18 */
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 <linux/vmalloc.h>
35#include <asm/div64.h>
36#include "ctree.h"
37#include "extent_map.h"
38#include "disk-io.h"
39#include "transaction.h"
40#include "print-tree.h"
41#include "volumes.h"
42#include "raid56.h"
43#include "async-thread.h"
44#include "check-integrity.h"
45#include "rcu-string.h"
46
47/* set when additional merges to this rbio are not allowed */
48#define RBIO_RMW_LOCKED_BIT 1
49
50/*
51 * set when this rbio is sitting in the hash, but it is just a cache
52 * of past RMW
53 */
54#define RBIO_CACHE_BIT 2
55
56/*
57 * set when it is safe to trust the stripe_pages for caching
58 */
59#define RBIO_CACHE_READY_BIT 3
60
61#define RBIO_CACHE_SIZE 1024
62
63enum btrfs_rbio_ops {
64 BTRFS_RBIO_WRITE,
65 BTRFS_RBIO_READ_REBUILD,
66 BTRFS_RBIO_PARITY_SCRUB,
67 BTRFS_RBIO_REBUILD_MISSING,
68};
69
70struct btrfs_raid_bio {
71 struct btrfs_fs_info *fs_info;
72 struct btrfs_bio *bbio;
73
74 /* while we're doing rmw on a stripe
75 * we put it into a hash table so we can
76 * lock the stripe and merge more rbios
77 * into it.
78 */
79 struct list_head hash_list;
80
81 /*
82 * LRU list for the stripe cache
83 */
84 struct list_head stripe_cache;
85
86 /*
87 * for scheduling work in the helper threads
88 */
89 struct btrfs_work work;
90
91 /*
92 * bio list and bio_list_lock are used
93 * to add more bios into the stripe
94 * in hopes of avoiding the full rmw
95 */
96 struct bio_list bio_list;
97 spinlock_t bio_list_lock;
98
99 /* also protected by the bio_list_lock, the
100 * plug list is used by the plugging code
101 * to collect partial bios while plugged. The
102 * stripe locking code also uses it to hand off
103 * the stripe lock to the next pending IO
104 */
105 struct list_head plug_list;
106
107 /*
108 * flags that tell us if it is safe to
109 * merge with this bio
110 */
111 unsigned long flags;
112
113 /* size of each individual stripe on disk */
114 int stripe_len;
115
116 /* number of data stripes (no p/q) */
117 int nr_data;
118
119 int real_stripes;
120
121 int stripe_npages;
122 /*
123 * set if we're doing a parity rebuild
124 * for a read from higher up, which is handled
125 * differently from a parity rebuild as part of
126 * rmw
127 */
128 enum btrfs_rbio_ops operation;
129
130 /* first bad stripe */
131 int faila;
132
133 /* second bad stripe (for raid6 use) */
134 int failb;
135
136 int scrubp;
137 /*
138 * number of pages needed to represent the full
139 * stripe
140 */
141 int nr_pages;
142
143 /*
144 * size of all the bios in the bio_list. This
145 * helps us decide if the rbio maps to a full
146 * stripe or not
147 */
148 int bio_list_bytes;
149
150 int generic_bio_cnt;
151
152 atomic_t refs;
153
154 atomic_t stripes_pending;
155
156 atomic_t error;
157 /*
158 * these are two arrays of pointers. We allocate the
159 * rbio big enough to hold them both and setup their
160 * locations when the rbio is allocated
161 */
162
163 /* pointers to pages that we allocated for
164 * reading/writing stripes directly from the disk (including P/Q)
165 */
166 struct page **stripe_pages;
167
168 /*
169 * pointers to the pages in the bio_list. Stored
170 * here for faster lookup
171 */
172 struct page **bio_pages;
173
174 /*
175 * bitmap to record which horizontal stripe has data
176 */
177 unsigned long *dbitmap;
178};
179
180static int __raid56_parity_recover(struct btrfs_raid_bio *rbio);
181static noinline void finish_rmw(struct btrfs_raid_bio *rbio);
182static void rmw_work(struct btrfs_work *work);
183static void read_rebuild_work(struct btrfs_work *work);
184static void async_rmw_stripe(struct btrfs_raid_bio *rbio);
185static void async_read_rebuild(struct btrfs_raid_bio *rbio);
186static int fail_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio);
187static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed);
188static void __free_raid_bio(struct btrfs_raid_bio *rbio);
189static void index_rbio_pages(struct btrfs_raid_bio *rbio);
190static int alloc_rbio_pages(struct btrfs_raid_bio *rbio);
191
192static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
193 int need_check);
194static void async_scrub_parity(struct btrfs_raid_bio *rbio);
195
196/*
197 * the stripe hash table is used for locking, and to collect
198 * bios in hopes of making a full stripe
199 */
200int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info)
201{
202 struct btrfs_stripe_hash_table *table;
203 struct btrfs_stripe_hash_table *x;
204 struct btrfs_stripe_hash *cur;
205 struct btrfs_stripe_hash *h;
206 int num_entries = 1 << BTRFS_STRIPE_HASH_TABLE_BITS;
207 int i;
208 int table_size;
209
210 if (info->stripe_hash_table)
211 return 0;
212
213 /*
214 * The table is large, starting with order 4 and can go as high as
215 * order 7 in case lock debugging is turned on.
216 *
217 * Try harder to allocate and fallback to vmalloc to lower the chance
218 * of a failing mount.
219 */
220 table_size = sizeof(*table) + sizeof(*h) * num_entries;
221 table = kzalloc(table_size, GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
222 if (!table) {
223 table = vzalloc(table_size);
224 if (!table)
225 return -ENOMEM;
226 }
227
228 spin_lock_init(&table->cache_lock);
229 INIT_LIST_HEAD(&table->stripe_cache);
230
231 h = table->table;
232
233 for (i = 0; i < num_entries; i++) {
234 cur = h + i;
235 INIT_LIST_HEAD(&cur->hash_list);
236 spin_lock_init(&cur->lock);
237 init_waitqueue_head(&cur->wait);
238 }
239
240 x = cmpxchg(&info->stripe_hash_table, NULL, table);
241 if (x)
242 kvfree(x);
243 return 0;
244}
245
246/*
247 * caching an rbio means to copy anything from the
248 * bio_pages array into the stripe_pages array. We
249 * use the page uptodate bit in the stripe cache array
250 * to indicate if it has valid data
251 *
252 * once the caching is done, we set the cache ready
253 * bit.
254 */
255static void cache_rbio_pages(struct btrfs_raid_bio *rbio)
256{
257 int i;
258 char *s;
259 char *d;
260 int ret;
261
262 ret = alloc_rbio_pages(rbio);
263 if (ret)
264 return;
265
266 for (i = 0; i < rbio->nr_pages; i++) {
267 if (!rbio->bio_pages[i])
268 continue;
269
270 s = kmap(rbio->bio_pages[i]);
271 d = kmap(rbio->stripe_pages[i]);
272
273 memcpy(d, s, PAGE_SIZE);
274
275 kunmap(rbio->bio_pages[i]);
276 kunmap(rbio->stripe_pages[i]);
277 SetPageUptodate(rbio->stripe_pages[i]);
278 }
279 set_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
280}
281
282/*
283 * we hash on the first logical address of the stripe
284 */
285static int rbio_bucket(struct btrfs_raid_bio *rbio)
286{
287 u64 num = rbio->bbio->raid_map[0];
288
289 /*
290 * we shift down quite a bit. We're using byte
291 * addressing, and most of the lower bits are zeros.
292 * This tends to upset hash_64, and it consistently
293 * returns just one or two different values.
294 *
295 * shifting off the lower bits fixes things.
296 */
297 return hash_64(num >> 16, BTRFS_STRIPE_HASH_TABLE_BITS);
298}
299
300/*
301 * stealing an rbio means taking all the uptodate pages from the stripe
302 * array in the source rbio and putting them into the destination rbio
303 */
304static void steal_rbio(struct btrfs_raid_bio *src, struct btrfs_raid_bio *dest)
305{
306 int i;
307 struct page *s;
308 struct page *d;
309
310 if (!test_bit(RBIO_CACHE_READY_BIT, &src->flags))
311 return;
312
313 for (i = 0; i < dest->nr_pages; i++) {
314 s = src->stripe_pages[i];
315 if (!s || !PageUptodate(s)) {
316 continue;
317 }
318
319 d = dest->stripe_pages[i];
320 if (d)
321 __free_page(d);
322
323 dest->stripe_pages[i] = s;
324 src->stripe_pages[i] = NULL;
325 }
326}
327
328/*
329 * merging means we take the bio_list from the victim and
330 * splice it into the destination. The victim should
331 * be discarded afterwards.
332 *
333 * must be called with dest->rbio_list_lock held
334 */
335static void merge_rbio(struct btrfs_raid_bio *dest,
336 struct btrfs_raid_bio *victim)
337{
338 bio_list_merge(&dest->bio_list, &victim->bio_list);
339 dest->bio_list_bytes += victim->bio_list_bytes;
340 dest->generic_bio_cnt += victim->generic_bio_cnt;
341 bio_list_init(&victim->bio_list);
342}
343
344/*
345 * used to prune items that are in the cache. The caller
346 * must hold the hash table lock.
347 */
348static void __remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
349{
350 int bucket = rbio_bucket(rbio);
351 struct btrfs_stripe_hash_table *table;
352 struct btrfs_stripe_hash *h;
353 int freeit = 0;
354
355 /*
356 * check the bit again under the hash table lock.
357 */
358 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
359 return;
360
361 table = rbio->fs_info->stripe_hash_table;
362 h = table->table + bucket;
363
364 /* hold the lock for the bucket because we may be
365 * removing it from the hash table
366 */
367 spin_lock(&h->lock);
368
369 /*
370 * hold the lock for the bio list because we need
371 * to make sure the bio list is empty
372 */
373 spin_lock(&rbio->bio_list_lock);
374
375 if (test_and_clear_bit(RBIO_CACHE_BIT, &rbio->flags)) {
376 list_del_init(&rbio->stripe_cache);
377 table->cache_size -= 1;
378 freeit = 1;
379
380 /* if the bio list isn't empty, this rbio is
381 * still involved in an IO. We take it out
382 * of the cache list, and drop the ref that
383 * was held for the list.
384 *
385 * If the bio_list was empty, we also remove
386 * the rbio from the hash_table, and drop
387 * the corresponding ref
388 */
389 if (bio_list_empty(&rbio->bio_list)) {
390 if (!list_empty(&rbio->hash_list)) {
391 list_del_init(&rbio->hash_list);
392 atomic_dec(&rbio->refs);
393 BUG_ON(!list_empty(&rbio->plug_list));
394 }
395 }
396 }
397
398 spin_unlock(&rbio->bio_list_lock);
399 spin_unlock(&h->lock);
400
401 if (freeit)
402 __free_raid_bio(rbio);
403}
404
405/*
406 * prune a given rbio from the cache
407 */
408static void remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
409{
410 struct btrfs_stripe_hash_table *table;
411 unsigned long flags;
412
413 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
414 return;
415
416 table = rbio->fs_info->stripe_hash_table;
417
418 spin_lock_irqsave(&table->cache_lock, flags);
419 __remove_rbio_from_cache(rbio);
420 spin_unlock_irqrestore(&table->cache_lock, flags);
421}
422
423/*
424 * remove everything in the cache
425 */
426static void btrfs_clear_rbio_cache(struct btrfs_fs_info *info)
427{
428 struct btrfs_stripe_hash_table *table;
429 unsigned long flags;
430 struct btrfs_raid_bio *rbio;
431
432 table = info->stripe_hash_table;
433
434 spin_lock_irqsave(&table->cache_lock, flags);
435 while (!list_empty(&table->stripe_cache)) {
436 rbio = list_entry(table->stripe_cache.next,
437 struct btrfs_raid_bio,
438 stripe_cache);
439 __remove_rbio_from_cache(rbio);
440 }
441 spin_unlock_irqrestore(&table->cache_lock, flags);
442}
443
444/*
445 * remove all cached entries and free the hash table
446 * used by unmount
447 */
448void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info)
449{
450 if (!info->stripe_hash_table)
451 return;
452 btrfs_clear_rbio_cache(info);
453 kvfree(info->stripe_hash_table);
454 info->stripe_hash_table = NULL;
455}
456
457/*
458 * insert an rbio into the stripe cache. It
459 * must have already been prepared by calling
460 * cache_rbio_pages
461 *
462 * If this rbio was already cached, it gets
463 * moved to the front of the lru.
464 *
465 * If the size of the rbio cache is too big, we
466 * prune an item.
467 */
468static void cache_rbio(struct btrfs_raid_bio *rbio)
469{
470 struct btrfs_stripe_hash_table *table;
471 unsigned long flags;
472
473 if (!test_bit(RBIO_CACHE_READY_BIT, &rbio->flags))
474 return;
475
476 table = rbio->fs_info->stripe_hash_table;
477
478 spin_lock_irqsave(&table->cache_lock, flags);
479 spin_lock(&rbio->bio_list_lock);
480
481 /* bump our ref if we were not in the list before */
482 if (!test_and_set_bit(RBIO_CACHE_BIT, &rbio->flags))
483 atomic_inc(&rbio->refs);
484
485 if (!list_empty(&rbio->stripe_cache)){
486 list_move(&rbio->stripe_cache, &table->stripe_cache);
487 } else {
488 list_add(&rbio->stripe_cache, &table->stripe_cache);
489 table->cache_size += 1;
490 }
491
492 spin_unlock(&rbio->bio_list_lock);
493
494 if (table->cache_size > RBIO_CACHE_SIZE) {
495 struct btrfs_raid_bio *found;
496
497 found = list_entry(table->stripe_cache.prev,
498 struct btrfs_raid_bio,
499 stripe_cache);
500
501 if (found != rbio)
502 __remove_rbio_from_cache(found);
503 }
504
505 spin_unlock_irqrestore(&table->cache_lock, flags);
506}
507
508/*
509 * helper function to run the xor_blocks api. It is only
510 * able to do MAX_XOR_BLOCKS at a time, so we need to
511 * loop through.
512 */
513static void run_xor(void **pages, int src_cnt, ssize_t len)
514{
515 int src_off = 0;
516 int xor_src_cnt = 0;
517 void *dest = pages[src_cnt];
518
519 while(src_cnt > 0) {
520 xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS);
521 xor_blocks(xor_src_cnt, len, dest, pages + src_off);
522
523 src_cnt -= xor_src_cnt;
524 src_off += xor_src_cnt;
525 }
526}
527
528/*
529 * returns true if the bio list inside this rbio
530 * covers an entire stripe (no rmw required).
531 * Must be called with the bio list lock held, or
532 * at a time when you know it is impossible to add
533 * new bios into the list
534 */
535static int __rbio_is_full(struct btrfs_raid_bio *rbio)
536{
537 unsigned long size = rbio->bio_list_bytes;
538 int ret = 1;
539
540 if (size != rbio->nr_data * rbio->stripe_len)
541 ret = 0;
542
543 BUG_ON(size > rbio->nr_data * rbio->stripe_len);
544 return ret;
545}
546
547static int rbio_is_full(struct btrfs_raid_bio *rbio)
548{
549 unsigned long flags;
550 int ret;
551
552 spin_lock_irqsave(&rbio->bio_list_lock, flags);
553 ret = __rbio_is_full(rbio);
554 spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
555 return ret;
556}
557
558/*
559 * returns 1 if it is safe to merge two rbios together.
560 * The merging is safe if the two rbios correspond to
561 * the same stripe and if they are both going in the same
562 * direction (read vs write), and if neither one is
563 * locked for final IO
564 *
565 * The caller is responsible for locking such that
566 * rmw_locked is safe to test
567 */
568static int rbio_can_merge(struct btrfs_raid_bio *last,
569 struct btrfs_raid_bio *cur)
570{
571 if (test_bit(RBIO_RMW_LOCKED_BIT, &last->flags) ||
572 test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags))
573 return 0;
574
575 /*
576 * we can't merge with cached rbios, since the
577 * idea is that when we merge the destination
578 * rbio is going to run our IO for us. We can
579 * steal from cached rbios though, other functions
580 * handle that.
581 */
582 if (test_bit(RBIO_CACHE_BIT, &last->flags) ||
583 test_bit(RBIO_CACHE_BIT, &cur->flags))
584 return 0;
585
586 if (last->bbio->raid_map[0] !=
587 cur->bbio->raid_map[0])
588 return 0;
589
590 /* we can't merge with different operations */
591 if (last->operation != cur->operation)
592 return 0;
593 /*
594 * We've need read the full stripe from the drive.
595 * check and repair the parity and write the new results.
596 *
597 * We're not allowed to add any new bios to the
598 * bio list here, anyone else that wants to
599 * change this stripe needs to do their own rmw.
600 */
601 if (last->operation == BTRFS_RBIO_PARITY_SCRUB ||
602 cur->operation == BTRFS_RBIO_PARITY_SCRUB)
603 return 0;
604
605 if (last->operation == BTRFS_RBIO_REBUILD_MISSING ||
606 cur->operation == BTRFS_RBIO_REBUILD_MISSING)
607 return 0;
608
609 return 1;
610}
611
612static int rbio_stripe_page_index(struct btrfs_raid_bio *rbio, int stripe,
613 int index)
614{
615 return stripe * rbio->stripe_npages + index;
616}
617
618/*
619 * these are just the pages from the rbio array, not from anything
620 * the FS sent down to us
621 */
622static struct page *rbio_stripe_page(struct btrfs_raid_bio *rbio, int stripe,
623 int index)
624{
625 return rbio->stripe_pages[rbio_stripe_page_index(rbio, stripe, index)];
626}
627
628/*
629 * helper to index into the pstripe
630 */
631static struct page *rbio_pstripe_page(struct btrfs_raid_bio *rbio, int index)
632{
633 return rbio_stripe_page(rbio, rbio->nr_data, index);
634}
635
636/*
637 * helper to index into the qstripe, returns null
638 * if there is no qstripe
639 */
640static struct page *rbio_qstripe_page(struct btrfs_raid_bio *rbio, int index)
641{
642 if (rbio->nr_data + 1 == rbio->real_stripes)
643 return NULL;
644 return rbio_stripe_page(rbio, rbio->nr_data + 1, index);
645}
646
647/*
648 * The first stripe in the table for a logical address
649 * has the lock. rbios are added in one of three ways:
650 *
651 * 1) Nobody has the stripe locked yet. The rbio is given
652 * the lock and 0 is returned. The caller must start the IO
653 * themselves.
654 *
655 * 2) Someone has the stripe locked, but we're able to merge
656 * with the lock owner. The rbio is freed and the IO will
657 * start automatically along with the existing rbio. 1 is returned.
658 *
659 * 3) Someone has the stripe locked, but we're not able to merge.
660 * The rbio is added to the lock owner's plug list, or merged into
661 * an rbio already on the plug list. When the lock owner unlocks,
662 * the next rbio on the list is run and the IO is started automatically.
663 * 1 is returned
664 *
665 * If we return 0, the caller still owns the rbio and must continue with
666 * IO submission. If we return 1, the caller must assume the rbio has
667 * already been freed.
668 */
669static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
670{
671 int bucket = rbio_bucket(rbio);
672 struct btrfs_stripe_hash *h = rbio->fs_info->stripe_hash_table->table + bucket;
673 struct btrfs_raid_bio *cur;
674 struct btrfs_raid_bio *pending;
675 unsigned long flags;
676 DEFINE_WAIT(wait);
677 struct btrfs_raid_bio *freeit = NULL;
678 struct btrfs_raid_bio *cache_drop = NULL;
679 int ret = 0;
680 int walk = 0;
681
682 spin_lock_irqsave(&h->lock, flags);
683 list_for_each_entry(cur, &h->hash_list, hash_list) {
684 walk++;
685 if (cur->bbio->raid_map[0] == rbio->bbio->raid_map[0]) {
686 spin_lock(&cur->bio_list_lock);
687
688 /* can we steal this cached rbio's pages? */
689 if (bio_list_empty(&cur->bio_list) &&
690 list_empty(&cur->plug_list) &&
691 test_bit(RBIO_CACHE_BIT, &cur->flags) &&
692 !test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) {
693 list_del_init(&cur->hash_list);
694 atomic_dec(&cur->refs);
695
696 steal_rbio(cur, rbio);
697 cache_drop = cur;
698 spin_unlock(&cur->bio_list_lock);
699
700 goto lockit;
701 }
702
703 /* can we merge into the lock owner? */
704 if (rbio_can_merge(cur, rbio)) {
705 merge_rbio(cur, rbio);
706 spin_unlock(&cur->bio_list_lock);
707 freeit = rbio;
708 ret = 1;
709 goto out;
710 }
711
712
713 /*
714 * we couldn't merge with the running
715 * rbio, see if we can merge with the
716 * pending ones. We don't have to
717 * check for rmw_locked because there
718 * is no way they are inside finish_rmw
719 * right now
720 */
721 list_for_each_entry(pending, &cur->plug_list,
722 plug_list) {
723 if (rbio_can_merge(pending, rbio)) {
724 merge_rbio(pending, rbio);
725 spin_unlock(&cur->bio_list_lock);
726 freeit = rbio;
727 ret = 1;
728 goto out;
729 }
730 }
731
732 /* no merging, put us on the tail of the plug list,
733 * our rbio will be started with the currently
734 * running rbio unlocks
735 */
736 list_add_tail(&rbio->plug_list, &cur->plug_list);
737 spin_unlock(&cur->bio_list_lock);
738 ret = 1;
739 goto out;
740 }
741 }
742lockit:
743 atomic_inc(&rbio->refs);
744 list_add(&rbio->hash_list, &h->hash_list);
745out:
746 spin_unlock_irqrestore(&h->lock, flags);
747 if (cache_drop)
748 remove_rbio_from_cache(cache_drop);
749 if (freeit)
750 __free_raid_bio(freeit);
751 return ret;
752}
753
754/*
755 * called as rmw or parity rebuild is completed. If the plug list has more
756 * rbios waiting for this stripe, the next one on the list will be started
757 */
758static noinline void unlock_stripe(struct btrfs_raid_bio *rbio)
759{
760 int bucket;
761 struct btrfs_stripe_hash *h;
762 unsigned long flags;
763 int keep_cache = 0;
764
765 bucket = rbio_bucket(rbio);
766 h = rbio->fs_info->stripe_hash_table->table + bucket;
767
768 if (list_empty(&rbio->plug_list))
769 cache_rbio(rbio);
770
771 spin_lock_irqsave(&h->lock, flags);
772 spin_lock(&rbio->bio_list_lock);
773
774 if (!list_empty(&rbio->hash_list)) {
775 /*
776 * if we're still cached and there is no other IO
777 * to perform, just leave this rbio here for others
778 * to steal from later
779 */
780 if (list_empty(&rbio->plug_list) &&
781 test_bit(RBIO_CACHE_BIT, &rbio->flags)) {
782 keep_cache = 1;
783 clear_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
784 BUG_ON(!bio_list_empty(&rbio->bio_list));
785 goto done;
786 }
787
788 list_del_init(&rbio->hash_list);
789 atomic_dec(&rbio->refs);
790
791 /*
792 * we use the plug list to hold all the rbios
793 * waiting for the chance to lock this stripe.
794 * hand the lock over to one of them.
795 */
796 if (!list_empty(&rbio->plug_list)) {
797 struct btrfs_raid_bio *next;
798 struct list_head *head = rbio->plug_list.next;
799
800 next = list_entry(head, struct btrfs_raid_bio,
801 plug_list);
802
803 list_del_init(&rbio->plug_list);
804
805 list_add(&next->hash_list, &h->hash_list);
806 atomic_inc(&next->refs);
807 spin_unlock(&rbio->bio_list_lock);
808 spin_unlock_irqrestore(&h->lock, flags);
809
810 if (next->operation == BTRFS_RBIO_READ_REBUILD)
811 async_read_rebuild(next);
812 else if (next->operation == BTRFS_RBIO_REBUILD_MISSING) {
813 steal_rbio(rbio, next);
814 async_read_rebuild(next);
815 } else if (next->operation == BTRFS_RBIO_WRITE) {
816 steal_rbio(rbio, next);
817 async_rmw_stripe(next);
818 } else if (next->operation == BTRFS_RBIO_PARITY_SCRUB) {
819 steal_rbio(rbio, next);
820 async_scrub_parity(next);
821 }
822
823 goto done_nolock;
824 /*
825 * The barrier for this waitqueue_active is not needed,
826 * we're protected by h->lock and can't miss a wakeup.
827 */
828 } else if (waitqueue_active(&h->wait)) {
829 spin_unlock(&rbio->bio_list_lock);
830 spin_unlock_irqrestore(&h->lock, flags);
831 wake_up(&h->wait);
832 goto done_nolock;
833 }
834 }
835done:
836 spin_unlock(&rbio->bio_list_lock);
837 spin_unlock_irqrestore(&h->lock, flags);
838
839done_nolock:
840 if (!keep_cache)
841 remove_rbio_from_cache(rbio);
842}
843
844static void __free_raid_bio(struct btrfs_raid_bio *rbio)
845{
846 int i;
847
848 WARN_ON(atomic_read(&rbio->refs) < 0);
849 if (!atomic_dec_and_test(&rbio->refs))
850 return;
851
852 WARN_ON(!list_empty(&rbio->stripe_cache));
853 WARN_ON(!list_empty(&rbio->hash_list));
854 WARN_ON(!bio_list_empty(&rbio->bio_list));
855
856 for (i = 0; i < rbio->nr_pages; i++) {
857 if (rbio->stripe_pages[i]) {
858 __free_page(rbio->stripe_pages[i]);
859 rbio->stripe_pages[i] = NULL;
860 }
861 }
862
863 btrfs_put_bbio(rbio->bbio);
864 kfree(rbio);
865}
866
867static void free_raid_bio(struct btrfs_raid_bio *rbio)
868{
869 unlock_stripe(rbio);
870 __free_raid_bio(rbio);
871}
872
873/*
874 * this frees the rbio and runs through all the bios in the
875 * bio_list and calls end_io on them
876 */
877static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, int err)
878{
879 struct bio *cur = bio_list_get(&rbio->bio_list);
880 struct bio *next;
881
882 if (rbio->generic_bio_cnt)
883 btrfs_bio_counter_sub(rbio->fs_info, rbio->generic_bio_cnt);
884
885 free_raid_bio(rbio);
886
887 while (cur) {
888 next = cur->bi_next;
889 cur->bi_next = NULL;
890 cur->bi_error = err;
891 bio_endio(cur);
892 cur = next;
893 }
894}
895
896/*
897 * end io function used by finish_rmw. When we finally
898 * get here, we've written a full stripe
899 */
900static void raid_write_end_io(struct bio *bio)
901{
902 struct btrfs_raid_bio *rbio = bio->bi_private;
903 int err = bio->bi_error;
904 int max_errors;
905
906 if (err)
907 fail_bio_stripe(rbio, bio);
908
909 bio_put(bio);
910
911 if (!atomic_dec_and_test(&rbio->stripes_pending))
912 return;
913
914 err = 0;
915
916 /* OK, we have read all the stripes we need to. */
917 max_errors = (rbio->operation == BTRFS_RBIO_PARITY_SCRUB) ?
918 0 : rbio->bbio->max_errors;
919 if (atomic_read(&rbio->error) > max_errors)
920 err = -EIO;
921
922 rbio_orig_end_io(rbio, err);
923}
924
925/*
926 * the read/modify/write code wants to use the original bio for
927 * any pages it included, and then use the rbio for everything
928 * else. This function decides if a given index (stripe number)
929 * and page number in that stripe fall inside the original bio
930 * or the rbio.
931 *
932 * if you set bio_list_only, you'll get a NULL back for any ranges
933 * that are outside the bio_list
934 *
935 * This doesn't take any refs on anything, you get a bare page pointer
936 * and the caller must bump refs as required.
937 *
938 * You must call index_rbio_pages once before you can trust
939 * the answers from this function.
940 */
941static struct page *page_in_rbio(struct btrfs_raid_bio *rbio,
942 int index, int pagenr, int bio_list_only)
943{
944 int chunk_page;
945 struct page *p = NULL;
946
947 chunk_page = index * (rbio->stripe_len >> PAGE_SHIFT) + pagenr;
948
949 spin_lock_irq(&rbio->bio_list_lock);
950 p = rbio->bio_pages[chunk_page];
951 spin_unlock_irq(&rbio->bio_list_lock);
952
953 if (p || bio_list_only)
954 return p;
955
956 return rbio->stripe_pages[chunk_page];
957}
958
959/*
960 * number of pages we need for the entire stripe across all the
961 * drives
962 */
963static unsigned long rbio_nr_pages(unsigned long stripe_len, int nr_stripes)
964{
965 return DIV_ROUND_UP(stripe_len, PAGE_SIZE) * nr_stripes;
966}
967
968/*
969 * allocation and initial setup for the btrfs_raid_bio. Not
970 * this does not allocate any pages for rbio->pages.
971 */
972static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info,
973 struct btrfs_bio *bbio,
974 u64 stripe_len)
975{
976 struct btrfs_raid_bio *rbio;
977 int nr_data = 0;
978 int real_stripes = bbio->num_stripes - bbio->num_tgtdevs;
979 int num_pages = rbio_nr_pages(stripe_len, real_stripes);
980 int stripe_npages = DIV_ROUND_UP(stripe_len, PAGE_SIZE);
981 void *p;
982
983 rbio = kzalloc(sizeof(*rbio) + num_pages * sizeof(struct page *) * 2 +
984 DIV_ROUND_UP(stripe_npages, BITS_PER_LONG) *
985 sizeof(long), GFP_NOFS);
986 if (!rbio)
987 return ERR_PTR(-ENOMEM);
988
989 bio_list_init(&rbio->bio_list);
990 INIT_LIST_HEAD(&rbio->plug_list);
991 spin_lock_init(&rbio->bio_list_lock);
992 INIT_LIST_HEAD(&rbio->stripe_cache);
993 INIT_LIST_HEAD(&rbio->hash_list);
994 rbio->bbio = bbio;
995 rbio->fs_info = fs_info;
996 rbio->stripe_len = stripe_len;
997 rbio->nr_pages = num_pages;
998 rbio->real_stripes = real_stripes;
999 rbio->stripe_npages = stripe_npages;
1000 rbio->faila = -1;
1001 rbio->failb = -1;
1002 atomic_set(&rbio->refs, 1);
1003 atomic_set(&rbio->error, 0);
1004 atomic_set(&rbio->stripes_pending, 0);
1005
1006 /*
1007 * the stripe_pages and bio_pages array point to the extra
1008 * memory we allocated past the end of the rbio
1009 */
1010 p = rbio + 1;
1011 rbio->stripe_pages = p;
1012 rbio->bio_pages = p + sizeof(struct page *) * num_pages;
1013 rbio->dbitmap = p + sizeof(struct page *) * num_pages * 2;
1014
1015 if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID5)
1016 nr_data = real_stripes - 1;
1017 else if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID6)
1018 nr_data = real_stripes - 2;
1019 else
1020 BUG();
1021
1022 rbio->nr_data = nr_data;
1023 return rbio;
1024}
1025
1026/* allocate pages for all the stripes in the bio, including parity */
1027static int alloc_rbio_pages(struct btrfs_raid_bio *rbio)
1028{
1029 int i;
1030 struct page *page;
1031
1032 for (i = 0; i < rbio->nr_pages; i++) {
1033 if (rbio->stripe_pages[i])
1034 continue;
1035 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1036 if (!page)
1037 return -ENOMEM;
1038 rbio->stripe_pages[i] = page;
1039 }
1040 return 0;
1041}
1042
1043/* only allocate pages for p/q stripes */
1044static int alloc_rbio_parity_pages(struct btrfs_raid_bio *rbio)
1045{
1046 int i;
1047 struct page *page;
1048
1049 i = rbio_stripe_page_index(rbio, rbio->nr_data, 0);
1050
1051 for (; i < rbio->nr_pages; i++) {
1052 if (rbio->stripe_pages[i])
1053 continue;
1054 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1055 if (!page)
1056 return -ENOMEM;
1057 rbio->stripe_pages[i] = page;
1058 }
1059 return 0;
1060}
1061
1062/*
1063 * add a single page from a specific stripe into our list of bios for IO
1064 * this will try to merge into existing bios if possible, and returns
1065 * zero if all went well.
1066 */
1067static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
1068 struct bio_list *bio_list,
1069 struct page *page,
1070 int stripe_nr,
1071 unsigned long page_index,
1072 unsigned long bio_max_len)
1073{
1074 struct bio *last = bio_list->tail;
1075 u64 last_end = 0;
1076 int ret;
1077 struct bio *bio;
1078 struct btrfs_bio_stripe *stripe;
1079 u64 disk_start;
1080
1081 stripe = &rbio->bbio->stripes[stripe_nr];
1082 disk_start = stripe->physical + (page_index << PAGE_SHIFT);
1083
1084 /* if the device is missing, just fail this stripe */
1085 if (!stripe->dev->bdev)
1086 return fail_rbio_index(rbio, stripe_nr);
1087
1088 /* see if we can add this page onto our existing bio */
1089 if (last) {
1090 last_end = (u64)last->bi_iter.bi_sector << 9;
1091 last_end += last->bi_iter.bi_size;
1092
1093 /*
1094 * we can't merge these if they are from different
1095 * devices or if they are not contiguous
1096 */
1097 if (last_end == disk_start && stripe->dev->bdev &&
1098 !last->bi_error &&
1099 last->bi_bdev == stripe->dev->bdev) {
1100 ret = bio_add_page(last, page, PAGE_SIZE, 0);
1101 if (ret == PAGE_SIZE)
1102 return 0;
1103 }
1104 }
1105
1106 /* put a new bio on the list */
1107 bio = btrfs_io_bio_alloc(GFP_NOFS, bio_max_len >> PAGE_SHIFT?:1);
1108 if (!bio)
1109 return -ENOMEM;
1110
1111 bio->bi_iter.bi_size = 0;
1112 bio->bi_bdev = stripe->dev->bdev;
1113 bio->bi_iter.bi_sector = disk_start >> 9;
1114
1115 bio_add_page(bio, page, PAGE_SIZE, 0);
1116 bio_list_add(bio_list, bio);
1117 return 0;
1118}
1119
1120/*
1121 * while we're doing the read/modify/write cycle, we could
1122 * have errors in reading pages off the disk. This checks
1123 * for errors and if we're not able to read the page it'll
1124 * trigger parity reconstruction. The rmw will be finished
1125 * after we've reconstructed the failed stripes
1126 */
1127static void validate_rbio_for_rmw(struct btrfs_raid_bio *rbio)
1128{
1129 if (rbio->faila >= 0 || rbio->failb >= 0) {
1130 BUG_ON(rbio->faila == rbio->real_stripes - 1);
1131 __raid56_parity_recover(rbio);
1132 } else {
1133 finish_rmw(rbio);
1134 }
1135}
1136
1137/*
1138 * helper function to walk our bio list and populate the bio_pages array with
1139 * the result. This seems expensive, but it is faster than constantly
1140 * searching through the bio list as we setup the IO in finish_rmw or stripe
1141 * reconstruction.
1142 *
1143 * This must be called before you trust the answers from page_in_rbio
1144 */
1145static void index_rbio_pages(struct btrfs_raid_bio *rbio)
1146{
1147 struct bio *bio;
1148 struct bio_vec *bvec;
1149 u64 start;
1150 unsigned long stripe_offset;
1151 unsigned long page_index;
1152 int i;
1153
1154 spin_lock_irq(&rbio->bio_list_lock);
1155 bio_list_for_each(bio, &rbio->bio_list) {
1156 start = (u64)bio->bi_iter.bi_sector << 9;
1157 stripe_offset = start - rbio->bbio->raid_map[0];
1158 page_index = stripe_offset >> PAGE_SHIFT;
1159
1160 bio_for_each_segment_all(bvec, bio, i)
1161 rbio->bio_pages[page_index + i] = bvec->bv_page;
1162 }
1163 spin_unlock_irq(&rbio->bio_list_lock);
1164}
1165
1166/*
1167 * this is called from one of two situations. We either
1168 * have a full stripe from the higher layers, or we've read all
1169 * the missing bits off disk.
1170 *
1171 * This will calculate the parity and then send down any
1172 * changed blocks.
1173 */
1174static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
1175{
1176 struct btrfs_bio *bbio = rbio->bbio;
1177 void *pointers[rbio->real_stripes];
1178 int nr_data = rbio->nr_data;
1179 int stripe;
1180 int pagenr;
1181 int p_stripe = -1;
1182 int q_stripe = -1;
1183 struct bio_list bio_list;
1184 struct bio *bio;
1185 int ret;
1186
1187 bio_list_init(&bio_list);
1188
1189 if (rbio->real_stripes - rbio->nr_data == 1) {
1190 p_stripe = rbio->real_stripes - 1;
1191 } else if (rbio->real_stripes - rbio->nr_data == 2) {
1192 p_stripe = rbio->real_stripes - 2;
1193 q_stripe = rbio->real_stripes - 1;
1194 } else {
1195 BUG();
1196 }
1197
1198 /* at this point we either have a full stripe,
1199 * or we've read the full stripe from the drive.
1200 * recalculate the parity and write the new results.
1201 *
1202 * We're not allowed to add any new bios to the
1203 * bio list here, anyone else that wants to
1204 * change this stripe needs to do their own rmw.
1205 */
1206 spin_lock_irq(&rbio->bio_list_lock);
1207 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1208 spin_unlock_irq(&rbio->bio_list_lock);
1209
1210 atomic_set(&rbio->error, 0);
1211
1212 /*
1213 * now that we've set rmw_locked, run through the
1214 * bio list one last time and map the page pointers
1215 *
1216 * We don't cache full rbios because we're assuming
1217 * the higher layers are unlikely to use this area of
1218 * the disk again soon. If they do use it again,
1219 * hopefully they will send another full bio.
1220 */
1221 index_rbio_pages(rbio);
1222 if (!rbio_is_full(rbio))
1223 cache_rbio_pages(rbio);
1224 else
1225 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
1226
1227 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1228 struct page *p;
1229 /* first collect one page from each data stripe */
1230 for (stripe = 0; stripe < nr_data; stripe++) {
1231 p = page_in_rbio(rbio, stripe, pagenr, 0);
1232 pointers[stripe] = kmap(p);
1233 }
1234
1235 /* then add the parity stripe */
1236 p = rbio_pstripe_page(rbio, pagenr);
1237 SetPageUptodate(p);
1238 pointers[stripe++] = kmap(p);
1239
1240 if (q_stripe != -1) {
1241
1242 /*
1243 * raid6, add the qstripe and call the
1244 * library function to fill in our p/q
1245 */
1246 p = rbio_qstripe_page(rbio, pagenr);
1247 SetPageUptodate(p);
1248 pointers[stripe++] = kmap(p);
1249
1250 raid6_call.gen_syndrome(rbio->real_stripes, PAGE_SIZE,
1251 pointers);
1252 } else {
1253 /* raid5 */
1254 memcpy(pointers[nr_data], pointers[0], PAGE_SIZE);
1255 run_xor(pointers + 1, nr_data - 1, PAGE_SIZE);
1256 }
1257
1258
1259 for (stripe = 0; stripe < rbio->real_stripes; stripe++)
1260 kunmap(page_in_rbio(rbio, stripe, pagenr, 0));
1261 }
1262
1263 /*
1264 * time to start writing. Make bios for everything from the
1265 * higher layers (the bio_list in our rbio) and our p/q. Ignore
1266 * everything else.
1267 */
1268 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1269 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1270 struct page *page;
1271 if (stripe < rbio->nr_data) {
1272 page = page_in_rbio(rbio, stripe, pagenr, 1);
1273 if (!page)
1274 continue;
1275 } else {
1276 page = rbio_stripe_page(rbio, stripe, pagenr);
1277 }
1278
1279 ret = rbio_add_io_page(rbio, &bio_list,
1280 page, stripe, pagenr, rbio->stripe_len);
1281 if (ret)
1282 goto cleanup;
1283 }
1284 }
1285
1286 if (likely(!bbio->num_tgtdevs))
1287 goto write_data;
1288
1289 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1290 if (!bbio->tgtdev_map[stripe])
1291 continue;
1292
1293 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1294 struct page *page;
1295 if (stripe < rbio->nr_data) {
1296 page = page_in_rbio(rbio, stripe, pagenr, 1);
1297 if (!page)
1298 continue;
1299 } else {
1300 page = rbio_stripe_page(rbio, stripe, pagenr);
1301 }
1302
1303 ret = rbio_add_io_page(rbio, &bio_list, page,
1304 rbio->bbio->tgtdev_map[stripe],
1305 pagenr, rbio->stripe_len);
1306 if (ret)
1307 goto cleanup;
1308 }
1309 }
1310
1311write_data:
1312 atomic_set(&rbio->stripes_pending, bio_list_size(&bio_list));
1313 BUG_ON(atomic_read(&rbio->stripes_pending) == 0);
1314
1315 while (1) {
1316 bio = bio_list_pop(&bio_list);
1317 if (!bio)
1318 break;
1319
1320 bio->bi_private = rbio;
1321 bio->bi_end_io = raid_write_end_io;
1322 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
1323
1324 submit_bio(bio);
1325 }
1326 return;
1327
1328cleanup:
1329 rbio_orig_end_io(rbio, -EIO);
1330}
1331
1332/*
1333 * helper to find the stripe number for a given bio. Used to figure out which
1334 * stripe has failed. This expects the bio to correspond to a physical disk,
1335 * so it looks up based on physical sector numbers.
1336 */
1337static int find_bio_stripe(struct btrfs_raid_bio *rbio,
1338 struct bio *bio)
1339{
1340 u64 physical = bio->bi_iter.bi_sector;
1341 u64 stripe_start;
1342 int i;
1343 struct btrfs_bio_stripe *stripe;
1344
1345 physical <<= 9;
1346
1347 for (i = 0; i < rbio->bbio->num_stripes; i++) {
1348 stripe = &rbio->bbio->stripes[i];
1349 stripe_start = stripe->physical;
1350 if (physical >= stripe_start &&
1351 physical < stripe_start + rbio->stripe_len &&
1352 bio->bi_bdev == stripe->dev->bdev) {
1353 return i;
1354 }
1355 }
1356 return -1;
1357}
1358
1359/*
1360 * helper to find the stripe number for a given
1361 * bio (before mapping). Used to figure out which stripe has
1362 * failed. This looks up based on logical block numbers.
1363 */
1364static int find_logical_bio_stripe(struct btrfs_raid_bio *rbio,
1365 struct bio *bio)
1366{
1367 u64 logical = bio->bi_iter.bi_sector;
1368 u64 stripe_start;
1369 int i;
1370
1371 logical <<= 9;
1372
1373 for (i = 0; i < rbio->nr_data; i++) {
1374 stripe_start = rbio->bbio->raid_map[i];
1375 if (logical >= stripe_start &&
1376 logical < stripe_start + rbio->stripe_len) {
1377 return i;
1378 }
1379 }
1380 return -1;
1381}
1382
1383/*
1384 * returns -EIO if we had too many failures
1385 */
1386static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed)
1387{
1388 unsigned long flags;
1389 int ret = 0;
1390
1391 spin_lock_irqsave(&rbio->bio_list_lock, flags);
1392
1393 /* we already know this stripe is bad, move on */
1394 if (rbio->faila == failed || rbio->failb == failed)
1395 goto out;
1396
1397 if (rbio->faila == -1) {
1398 /* first failure on this rbio */
1399 rbio->faila = failed;
1400 atomic_inc(&rbio->error);
1401 } else if (rbio->failb == -1) {
1402 /* second failure on this rbio */
1403 rbio->failb = failed;
1404 atomic_inc(&rbio->error);
1405 } else {
1406 ret = -EIO;
1407 }
1408out:
1409 spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
1410
1411 return ret;
1412}
1413
1414/*
1415 * helper to fail a stripe based on a physical disk
1416 * bio.
1417 */
1418static int fail_bio_stripe(struct btrfs_raid_bio *rbio,
1419 struct bio *bio)
1420{
1421 int failed = find_bio_stripe(rbio, bio);
1422
1423 if (failed < 0)
1424 return -EIO;
1425
1426 return fail_rbio_index(rbio, failed);
1427}
1428
1429/*
1430 * this sets each page in the bio uptodate. It should only be used on private
1431 * rbio pages, nothing that comes in from the higher layers
1432 */
1433static void set_bio_pages_uptodate(struct bio *bio)
1434{
1435 struct bio_vec *bvec;
1436 int i;
1437
1438 bio_for_each_segment_all(bvec, bio, i)
1439 SetPageUptodate(bvec->bv_page);
1440}
1441
1442/*
1443 * end io for the read phase of the rmw cycle. All the bios here are physical
1444 * stripe bios we've read from the disk so we can recalculate the parity of the
1445 * stripe.
1446 *
1447 * This will usually kick off finish_rmw once all the bios are read in, but it
1448 * may trigger parity reconstruction if we had any errors along the way
1449 */
1450static void raid_rmw_end_io(struct bio *bio)
1451{
1452 struct btrfs_raid_bio *rbio = bio->bi_private;
1453
1454 if (bio->bi_error)
1455 fail_bio_stripe(rbio, bio);
1456 else
1457 set_bio_pages_uptodate(bio);
1458
1459 bio_put(bio);
1460
1461 if (!atomic_dec_and_test(&rbio->stripes_pending))
1462 return;
1463
1464 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
1465 goto cleanup;
1466
1467 /*
1468 * this will normally call finish_rmw to start our write
1469 * but if there are any failed stripes we'll reconstruct
1470 * from parity first
1471 */
1472 validate_rbio_for_rmw(rbio);
1473 return;
1474
1475cleanup:
1476
1477 rbio_orig_end_io(rbio, -EIO);
1478}
1479
1480static void async_rmw_stripe(struct btrfs_raid_bio *rbio)
1481{
1482 btrfs_init_work(&rbio->work, btrfs_rmw_helper, rmw_work, NULL, NULL);
1483 btrfs_queue_work(rbio->fs_info->rmw_workers, &rbio->work);
1484}
1485
1486static void async_read_rebuild(struct btrfs_raid_bio *rbio)
1487{
1488 btrfs_init_work(&rbio->work, btrfs_rmw_helper,
1489 read_rebuild_work, NULL, NULL);
1490
1491 btrfs_queue_work(rbio->fs_info->rmw_workers, &rbio->work);
1492}
1493
1494/*
1495 * the stripe must be locked by the caller. It will
1496 * unlock after all the writes are done
1497 */
1498static int raid56_rmw_stripe(struct btrfs_raid_bio *rbio)
1499{
1500 int bios_to_read = 0;
1501 struct bio_list bio_list;
1502 int ret;
1503 int pagenr;
1504 int stripe;
1505 struct bio *bio;
1506
1507 bio_list_init(&bio_list);
1508
1509 ret = alloc_rbio_pages(rbio);
1510 if (ret)
1511 goto cleanup;
1512
1513 index_rbio_pages(rbio);
1514
1515 atomic_set(&rbio->error, 0);
1516 /*
1517 * build a list of bios to read all the missing parts of this
1518 * stripe
1519 */
1520 for (stripe = 0; stripe < rbio->nr_data; stripe++) {
1521 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1522 struct page *page;
1523 /*
1524 * we want to find all the pages missing from
1525 * the rbio and read them from the disk. If
1526 * page_in_rbio finds a page in the bio list
1527 * we don't need to read it off the stripe.
1528 */
1529 page = page_in_rbio(rbio, stripe, pagenr, 1);
1530 if (page)
1531 continue;
1532
1533 page = rbio_stripe_page(rbio, stripe, pagenr);
1534 /*
1535 * the bio cache may have handed us an uptodate
1536 * page. If so, be happy and use it
1537 */
1538 if (PageUptodate(page))
1539 continue;
1540
1541 ret = rbio_add_io_page(rbio, &bio_list, page,
1542 stripe, pagenr, rbio->stripe_len);
1543 if (ret)
1544 goto cleanup;
1545 }
1546 }
1547
1548 bios_to_read = bio_list_size(&bio_list);
1549 if (!bios_to_read) {
1550 /*
1551 * this can happen if others have merged with
1552 * us, it means there is nothing left to read.
1553 * But if there are missing devices it may not be
1554 * safe to do the full stripe write yet.
1555 */
1556 goto finish;
1557 }
1558
1559 /*
1560 * the bbio may be freed once we submit the last bio. Make sure
1561 * not to touch it after that
1562 */
1563 atomic_set(&rbio->stripes_pending, bios_to_read);
1564 while (1) {
1565 bio = bio_list_pop(&bio_list);
1566 if (!bio)
1567 break;
1568
1569 bio->bi_private = rbio;
1570 bio->bi_end_io = raid_rmw_end_io;
1571 bio_set_op_attrs(bio, REQ_OP_READ, 0);
1572
1573 btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
1574
1575 submit_bio(bio);
1576 }
1577 /* the actual write will happen once the reads are done */
1578 return 0;
1579
1580cleanup:
1581 rbio_orig_end_io(rbio, -EIO);
1582 return -EIO;
1583
1584finish:
1585 validate_rbio_for_rmw(rbio);
1586 return 0;
1587}
1588
1589/*
1590 * if the upper layers pass in a full stripe, we thank them by only allocating
1591 * enough pages to hold the parity, and sending it all down quickly.
1592 */
1593static int full_stripe_write(struct btrfs_raid_bio *rbio)
1594{
1595 int ret;
1596
1597 ret = alloc_rbio_parity_pages(rbio);
1598 if (ret) {
1599 __free_raid_bio(rbio);
1600 return ret;
1601 }
1602
1603 ret = lock_stripe_add(rbio);
1604 if (ret == 0)
1605 finish_rmw(rbio);
1606 return 0;
1607}
1608
1609/*
1610 * partial stripe writes get handed over to async helpers.
1611 * We're really hoping to merge a few more writes into this
1612 * rbio before calculating new parity
1613 */
1614static int partial_stripe_write(struct btrfs_raid_bio *rbio)
1615{
1616 int ret;
1617
1618 ret = lock_stripe_add(rbio);
1619 if (ret == 0)
1620 async_rmw_stripe(rbio);
1621 return 0;
1622}
1623
1624/*
1625 * sometimes while we were reading from the drive to
1626 * recalculate parity, enough new bios come into create
1627 * a full stripe. So we do a check here to see if we can
1628 * go directly to finish_rmw
1629 */
1630static int __raid56_parity_write(struct btrfs_raid_bio *rbio)
1631{
1632 /* head off into rmw land if we don't have a full stripe */
1633 if (!rbio_is_full(rbio))
1634 return partial_stripe_write(rbio);
1635 return full_stripe_write(rbio);
1636}
1637
1638/*
1639 * We use plugging call backs to collect full stripes.
1640 * Any time we get a partial stripe write while plugged
1641 * we collect it into a list. When the unplug comes down,
1642 * we sort the list by logical block number and merge
1643 * everything we can into the same rbios
1644 */
1645struct btrfs_plug_cb {
1646 struct blk_plug_cb cb;
1647 struct btrfs_fs_info *info;
1648 struct list_head rbio_list;
1649 struct btrfs_work work;
1650};
1651
1652/*
1653 * rbios on the plug list are sorted for easier merging.
1654 */
1655static int plug_cmp(void *priv, struct list_head *a, struct list_head *b)
1656{
1657 struct btrfs_raid_bio *ra = container_of(a, struct btrfs_raid_bio,
1658 plug_list);
1659 struct btrfs_raid_bio *rb = container_of(b, struct btrfs_raid_bio,
1660 plug_list);
1661 u64 a_sector = ra->bio_list.head->bi_iter.bi_sector;
1662 u64 b_sector = rb->bio_list.head->bi_iter.bi_sector;
1663
1664 if (a_sector < b_sector)
1665 return -1;
1666 if (a_sector > b_sector)
1667 return 1;
1668 return 0;
1669}
1670
1671static void run_plug(struct btrfs_plug_cb *plug)
1672{
1673 struct btrfs_raid_bio *cur;
1674 struct btrfs_raid_bio *last = NULL;
1675
1676 /*
1677 * sort our plug list then try to merge
1678 * everything we can in hopes of creating full
1679 * stripes.
1680 */
1681 list_sort(NULL, &plug->rbio_list, plug_cmp);
1682 while (!list_empty(&plug->rbio_list)) {
1683 cur = list_entry(plug->rbio_list.next,
1684 struct btrfs_raid_bio, plug_list);
1685 list_del_init(&cur->plug_list);
1686
1687 if (rbio_is_full(cur)) {
1688 /* we have a full stripe, send it down */
1689 full_stripe_write(cur);
1690 continue;
1691 }
1692 if (last) {
1693 if (rbio_can_merge(last, cur)) {
1694 merge_rbio(last, cur);
1695 __free_raid_bio(cur);
1696 continue;
1697
1698 }
1699 __raid56_parity_write(last);
1700 }
1701 last = cur;
1702 }
1703 if (last) {
1704 __raid56_parity_write(last);
1705 }
1706 kfree(plug);
1707}
1708
1709/*
1710 * if the unplug comes from schedule, we have to push the
1711 * work off to a helper thread
1712 */
1713static void unplug_work(struct btrfs_work *work)
1714{
1715 struct btrfs_plug_cb *plug;
1716 plug = container_of(work, struct btrfs_plug_cb, work);
1717 run_plug(plug);
1718}
1719
1720static void btrfs_raid_unplug(struct blk_plug_cb *cb, bool from_schedule)
1721{
1722 struct btrfs_plug_cb *plug;
1723 plug = container_of(cb, struct btrfs_plug_cb, cb);
1724
1725 if (from_schedule) {
1726 btrfs_init_work(&plug->work, btrfs_rmw_helper,
1727 unplug_work, NULL, NULL);
1728 btrfs_queue_work(plug->info->rmw_workers,
1729 &plug->work);
1730 return;
1731 }
1732 run_plug(plug);
1733}
1734
1735/*
1736 * our main entry point for writes from the rest of the FS.
1737 */
1738int raid56_parity_write(struct btrfs_fs_info *fs_info, struct bio *bio,
1739 struct btrfs_bio *bbio, u64 stripe_len)
1740{
1741 struct btrfs_raid_bio *rbio;
1742 struct btrfs_plug_cb *plug = NULL;
1743 struct blk_plug_cb *cb;
1744 int ret;
1745
1746 rbio = alloc_rbio(fs_info, bbio, stripe_len);
1747 if (IS_ERR(rbio)) {
1748 btrfs_put_bbio(bbio);
1749 return PTR_ERR(rbio);
1750 }
1751 bio_list_add(&rbio->bio_list, bio);
1752 rbio->bio_list_bytes = bio->bi_iter.bi_size;
1753 rbio->operation = BTRFS_RBIO_WRITE;
1754
1755 btrfs_bio_counter_inc_noblocked(fs_info);
1756 rbio->generic_bio_cnt = 1;
1757
1758 /*
1759 * don't plug on full rbios, just get them out the door
1760 * as quickly as we can
1761 */
1762 if (rbio_is_full(rbio)) {
1763 ret = full_stripe_write(rbio);
1764 if (ret)
1765 btrfs_bio_counter_dec(fs_info);
1766 return ret;
1767 }
1768
1769 cb = blk_check_plugged(btrfs_raid_unplug, fs_info, sizeof(*plug));
1770 if (cb) {
1771 plug = container_of(cb, struct btrfs_plug_cb, cb);
1772 if (!plug->info) {
1773 plug->info = fs_info;
1774 INIT_LIST_HEAD(&plug->rbio_list);
1775 }
1776 list_add_tail(&rbio->plug_list, &plug->rbio_list);
1777 ret = 0;
1778 } else {
1779 ret = __raid56_parity_write(rbio);
1780 if (ret)
1781 btrfs_bio_counter_dec(fs_info);
1782 }
1783 return ret;
1784}
1785
1786/*
1787 * all parity reconstruction happens here. We've read in everything
1788 * we can find from the drives and this does the heavy lifting of
1789 * sorting the good from the bad.
1790 */
1791static void __raid_recover_end_io(struct btrfs_raid_bio *rbio)
1792{
1793 int pagenr, stripe;
1794 void **pointers;
1795 int faila = -1, failb = -1;
1796 struct page *page;
1797 int err;
1798 int i;
1799
1800 pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
1801 if (!pointers) {
1802 err = -ENOMEM;
1803 goto cleanup_io;
1804 }
1805
1806 faila = rbio->faila;
1807 failb = rbio->failb;
1808
1809 if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1810 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) {
1811 spin_lock_irq(&rbio->bio_list_lock);
1812 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1813 spin_unlock_irq(&rbio->bio_list_lock);
1814 }
1815
1816 index_rbio_pages(rbio);
1817
1818 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1819 /*
1820 * Now we just use bitmap to mark the horizontal stripes in
1821 * which we have data when doing parity scrub.
1822 */
1823 if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB &&
1824 !test_bit(pagenr, rbio->dbitmap))
1825 continue;
1826
1827 /* setup our array of pointers with pages
1828 * from each stripe
1829 */
1830 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1831 /*
1832 * if we're rebuilding a read, we have to use
1833 * pages from the bio list
1834 */
1835 if ((rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1836 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) &&
1837 (stripe == faila || stripe == failb)) {
1838 page = page_in_rbio(rbio, stripe, pagenr, 0);
1839 } else {
1840 page = rbio_stripe_page(rbio, stripe, pagenr);
1841 }
1842 pointers[stripe] = kmap(page);
1843 }
1844
1845 /* all raid6 handling here */
1846 if (rbio->bbio->map_type & BTRFS_BLOCK_GROUP_RAID6) {
1847 /*
1848 * single failure, rebuild from parity raid5
1849 * style
1850 */
1851 if (failb < 0) {
1852 if (faila == rbio->nr_data) {
1853 /*
1854 * Just the P stripe has failed, without
1855 * a bad data or Q stripe.
1856 * TODO, we should redo the xor here.
1857 */
1858 err = -EIO;
1859 goto cleanup;
1860 }
1861 /*
1862 * a single failure in raid6 is rebuilt
1863 * in the pstripe code below
1864 */
1865 goto pstripe;
1866 }
1867
1868 /* make sure our ps and qs are in order */
1869 if (faila > failb) {
1870 int tmp = failb;
1871 failb = faila;
1872 faila = tmp;
1873 }
1874
1875 /* if the q stripe is failed, do a pstripe reconstruction
1876 * from the xors.
1877 * If both the q stripe and the P stripe are failed, we're
1878 * here due to a crc mismatch and we can't give them the
1879 * data they want
1880 */
1881 if (rbio->bbio->raid_map[failb] == RAID6_Q_STRIPE) {
1882 if (rbio->bbio->raid_map[faila] ==
1883 RAID5_P_STRIPE) {
1884 err = -EIO;
1885 goto cleanup;
1886 }
1887 /*
1888 * otherwise we have one bad data stripe and
1889 * a good P stripe. raid5!
1890 */
1891 goto pstripe;
1892 }
1893
1894 if (rbio->bbio->raid_map[failb] == RAID5_P_STRIPE) {
1895 raid6_datap_recov(rbio->real_stripes,
1896 PAGE_SIZE, faila, pointers);
1897 } else {
1898 raid6_2data_recov(rbio->real_stripes,
1899 PAGE_SIZE, faila, failb,
1900 pointers);
1901 }
1902 } else {
1903 void *p;
1904
1905 /* rebuild from P stripe here (raid5 or raid6) */
1906 BUG_ON(failb != -1);
1907pstripe:
1908 /* Copy parity block into failed block to start with */
1909 memcpy(pointers[faila],
1910 pointers[rbio->nr_data],
1911 PAGE_SIZE);
1912
1913 /* rearrange the pointer array */
1914 p = pointers[faila];
1915 for (stripe = faila; stripe < rbio->nr_data - 1; stripe++)
1916 pointers[stripe] = pointers[stripe + 1];
1917 pointers[rbio->nr_data - 1] = p;
1918
1919 /* xor in the rest */
1920 run_xor(pointers, rbio->nr_data - 1, PAGE_SIZE);
1921 }
1922 /* if we're doing this rebuild as part of an rmw, go through
1923 * and set all of our private rbio pages in the
1924 * failed stripes as uptodate. This way finish_rmw will
1925 * know they can be trusted. If this was a read reconstruction,
1926 * other endio functions will fiddle the uptodate bits
1927 */
1928 if (rbio->operation == BTRFS_RBIO_WRITE) {
1929 for (i = 0; i < rbio->stripe_npages; i++) {
1930 if (faila != -1) {
1931 page = rbio_stripe_page(rbio, faila, i);
1932 SetPageUptodate(page);
1933 }
1934 if (failb != -1) {
1935 page = rbio_stripe_page(rbio, failb, i);
1936 SetPageUptodate(page);
1937 }
1938 }
1939 }
1940 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1941 /*
1942 * if we're rebuilding a read, we have to use
1943 * pages from the bio list
1944 */
1945 if ((rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1946 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) &&
1947 (stripe == faila || stripe == failb)) {
1948 page = page_in_rbio(rbio, stripe, pagenr, 0);
1949 } else {
1950 page = rbio_stripe_page(rbio, stripe, pagenr);
1951 }
1952 kunmap(page);
1953 }
1954 }
1955
1956 err = 0;
1957cleanup:
1958 kfree(pointers);
1959
1960cleanup_io:
1961 if (rbio->operation == BTRFS_RBIO_READ_REBUILD) {
1962 if (err == 0)
1963 cache_rbio_pages(rbio);
1964 else
1965 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
1966
1967 rbio_orig_end_io(rbio, err);
1968 } else if (rbio->operation == BTRFS_RBIO_REBUILD_MISSING) {
1969 rbio_orig_end_io(rbio, err);
1970 } else if (err == 0) {
1971 rbio->faila = -1;
1972 rbio->failb = -1;
1973
1974 if (rbio->operation == BTRFS_RBIO_WRITE)
1975 finish_rmw(rbio);
1976 else if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB)
1977 finish_parity_scrub(rbio, 0);
1978 else
1979 BUG();
1980 } else {
1981 rbio_orig_end_io(rbio, err);
1982 }
1983}
1984
1985/*
1986 * This is called only for stripes we've read from disk to
1987 * reconstruct the parity.
1988 */
1989static void raid_recover_end_io(struct bio *bio)
1990{
1991 struct btrfs_raid_bio *rbio = bio->bi_private;
1992
1993 /*
1994 * we only read stripe pages off the disk, set them
1995 * up to date if there were no errors
1996 */
1997 if (bio->bi_error)
1998 fail_bio_stripe(rbio, bio);
1999 else
2000 set_bio_pages_uptodate(bio);
2001 bio_put(bio);
2002
2003 if (!atomic_dec_and_test(&rbio->stripes_pending))
2004 return;
2005
2006 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
2007 rbio_orig_end_io(rbio, -EIO);
2008 else
2009 __raid_recover_end_io(rbio);
2010}
2011
2012/*
2013 * reads everything we need off the disk to reconstruct
2014 * the parity. endio handlers trigger final reconstruction
2015 * when the IO is done.
2016 *
2017 * This is used both for reads from the higher layers and for
2018 * parity construction required to finish a rmw cycle.
2019 */
2020static int __raid56_parity_recover(struct btrfs_raid_bio *rbio)
2021{
2022 int bios_to_read = 0;
2023 struct bio_list bio_list;
2024 int ret;
2025 int pagenr;
2026 int stripe;
2027 struct bio *bio;
2028
2029 bio_list_init(&bio_list);
2030
2031 ret = alloc_rbio_pages(rbio);
2032 if (ret)
2033 goto cleanup;
2034
2035 atomic_set(&rbio->error, 0);
2036
2037 /*
2038 * read everything that hasn't failed. Thanks to the
2039 * stripe cache, it is possible that some or all of these
2040 * pages are going to be uptodate.
2041 */
2042 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
2043 if (rbio->faila == stripe || rbio->failb == stripe) {
2044 atomic_inc(&rbio->error);
2045 continue;
2046 }
2047
2048 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
2049 struct page *p;
2050
2051 /*
2052 * the rmw code may have already read this
2053 * page in
2054 */
2055 p = rbio_stripe_page(rbio, stripe, pagenr);
2056 if (PageUptodate(p))
2057 continue;
2058
2059 ret = rbio_add_io_page(rbio, &bio_list,
2060 rbio_stripe_page(rbio, stripe, pagenr),
2061 stripe, pagenr, rbio->stripe_len);
2062 if (ret < 0)
2063 goto cleanup;
2064 }
2065 }
2066
2067 bios_to_read = bio_list_size(&bio_list);
2068 if (!bios_to_read) {
2069 /*
2070 * we might have no bios to read just because the pages
2071 * were up to date, or we might have no bios to read because
2072 * the devices were gone.
2073 */
2074 if (atomic_read(&rbio->error) <= rbio->bbio->max_errors) {
2075 __raid_recover_end_io(rbio);
2076 goto out;
2077 } else {
2078 goto cleanup;
2079 }
2080 }
2081
2082 /*
2083 * the bbio may be freed once we submit the last bio. Make sure
2084 * not to touch it after that
2085 */
2086 atomic_set(&rbio->stripes_pending, bios_to_read);
2087 while (1) {
2088 bio = bio_list_pop(&bio_list);
2089 if (!bio)
2090 break;
2091
2092 bio->bi_private = rbio;
2093 bio->bi_end_io = raid_recover_end_io;
2094 bio_set_op_attrs(bio, REQ_OP_READ, 0);
2095
2096 btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
2097
2098 submit_bio(bio);
2099 }
2100out:
2101 return 0;
2102
2103cleanup:
2104 if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
2105 rbio->operation == BTRFS_RBIO_REBUILD_MISSING)
2106 rbio_orig_end_io(rbio, -EIO);
2107 return -EIO;
2108}
2109
2110/*
2111 * the main entry point for reads from the higher layers. This
2112 * is really only called when the normal read path had a failure,
2113 * so we assume the bio they send down corresponds to a failed part
2114 * of the drive.
2115 */
2116int raid56_parity_recover(struct btrfs_fs_info *fs_info, struct bio *bio,
2117 struct btrfs_bio *bbio, u64 stripe_len,
2118 int mirror_num, int generic_io)
2119{
2120 struct btrfs_raid_bio *rbio;
2121 int ret;
2122
2123 rbio = alloc_rbio(fs_info, bbio, stripe_len);
2124 if (IS_ERR(rbio)) {
2125 if (generic_io)
2126 btrfs_put_bbio(bbio);
2127 return PTR_ERR(rbio);
2128 }
2129
2130 rbio->operation = BTRFS_RBIO_READ_REBUILD;
2131 bio_list_add(&rbio->bio_list, bio);
2132 rbio->bio_list_bytes = bio->bi_iter.bi_size;
2133
2134 rbio->faila = find_logical_bio_stripe(rbio, bio);
2135 if (rbio->faila == -1) {
2136 btrfs_warn(fs_info,
2137 "%s could not find the bad stripe in raid56 so that we cannot recover any more (bio has logical %llu len %llu, bbio has map_type %llu)",
2138 __func__, (u64)bio->bi_iter.bi_sector << 9,
2139 (u64)bio->bi_iter.bi_size, bbio->map_type);
2140 if (generic_io)
2141 btrfs_put_bbio(bbio);
2142 kfree(rbio);
2143 return -EIO;
2144 }
2145
2146 if (generic_io) {
2147 btrfs_bio_counter_inc_noblocked(fs_info);
2148 rbio->generic_bio_cnt = 1;
2149 } else {
2150 btrfs_get_bbio(bbio);
2151 }
2152
2153 /*
2154 * reconstruct from the q stripe if they are
2155 * asking for mirror 3
2156 */
2157 if (mirror_num == 3)
2158 rbio->failb = rbio->real_stripes - 2;
2159
2160 ret = lock_stripe_add(rbio);
2161
2162 /*
2163 * __raid56_parity_recover will end the bio with
2164 * any errors it hits. We don't want to return
2165 * its error value up the stack because our caller
2166 * will end up calling bio_endio with any nonzero
2167 * return
2168 */
2169 if (ret == 0)
2170 __raid56_parity_recover(rbio);
2171 /*
2172 * our rbio has been added to the list of
2173 * rbios that will be handled after the
2174 * currently lock owner is done
2175 */
2176 return 0;
2177
2178}
2179
2180static void rmw_work(struct btrfs_work *work)
2181{
2182 struct btrfs_raid_bio *rbio;
2183
2184 rbio = container_of(work, struct btrfs_raid_bio, work);
2185 raid56_rmw_stripe(rbio);
2186}
2187
2188static void read_rebuild_work(struct btrfs_work *work)
2189{
2190 struct btrfs_raid_bio *rbio;
2191
2192 rbio = container_of(work, struct btrfs_raid_bio, work);
2193 __raid56_parity_recover(rbio);
2194}
2195
2196/*
2197 * The following code is used to scrub/replace the parity stripe
2198 *
2199 * Note: We need make sure all the pages that add into the scrub/replace
2200 * raid bio are correct and not be changed during the scrub/replace. That
2201 * is those pages just hold metadata or file data with checksum.
2202 */
2203
2204struct btrfs_raid_bio *
2205raid56_parity_alloc_scrub_rbio(struct btrfs_fs_info *fs_info, struct bio *bio,
2206 struct btrfs_bio *bbio, u64 stripe_len,
2207 struct btrfs_device *scrub_dev,
2208 unsigned long *dbitmap, int stripe_nsectors)
2209{
2210 struct btrfs_raid_bio *rbio;
2211 int i;
2212
2213 rbio = alloc_rbio(fs_info, bbio, stripe_len);
2214 if (IS_ERR(rbio))
2215 return NULL;
2216 bio_list_add(&rbio->bio_list, bio);
2217 /*
2218 * This is a special bio which is used to hold the completion handler
2219 * and make the scrub rbio is similar to the other types
2220 */
2221 ASSERT(!bio->bi_iter.bi_size);
2222 rbio->operation = BTRFS_RBIO_PARITY_SCRUB;
2223
2224 for (i = 0; i < rbio->real_stripes; i++) {
2225 if (bbio->stripes[i].dev == scrub_dev) {
2226 rbio->scrubp = i;
2227 break;
2228 }
2229 }
2230
2231 /* Now we just support the sectorsize equals to page size */
2232 ASSERT(fs_info->sectorsize == PAGE_SIZE);
2233 ASSERT(rbio->stripe_npages == stripe_nsectors);
2234 bitmap_copy(rbio->dbitmap, dbitmap, stripe_nsectors);
2235
2236 return rbio;
2237}
2238
2239/* Used for both parity scrub and missing. */
2240void raid56_add_scrub_pages(struct btrfs_raid_bio *rbio, struct page *page,
2241 u64 logical)
2242{
2243 int stripe_offset;
2244 int index;
2245
2246 ASSERT(logical >= rbio->bbio->raid_map[0]);
2247 ASSERT(logical + PAGE_SIZE <= rbio->bbio->raid_map[0] +
2248 rbio->stripe_len * rbio->nr_data);
2249 stripe_offset = (int)(logical - rbio->bbio->raid_map[0]);
2250 index = stripe_offset >> PAGE_SHIFT;
2251 rbio->bio_pages[index] = page;
2252}
2253
2254/*
2255 * We just scrub the parity that we have correct data on the same horizontal,
2256 * so we needn't allocate all pages for all the stripes.
2257 */
2258static int alloc_rbio_essential_pages(struct btrfs_raid_bio *rbio)
2259{
2260 int i;
2261 int bit;
2262 int index;
2263 struct page *page;
2264
2265 for_each_set_bit(bit, rbio->dbitmap, rbio->stripe_npages) {
2266 for (i = 0; i < rbio->real_stripes; i++) {
2267 index = i * rbio->stripe_npages + bit;
2268 if (rbio->stripe_pages[index])
2269 continue;
2270
2271 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2272 if (!page)
2273 return -ENOMEM;
2274 rbio->stripe_pages[index] = page;
2275 }
2276 }
2277 return 0;
2278}
2279
2280static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
2281 int need_check)
2282{
2283 struct btrfs_bio *bbio = rbio->bbio;
2284 void *pointers[rbio->real_stripes];
2285 DECLARE_BITMAP(pbitmap, rbio->stripe_npages);
2286 int nr_data = rbio->nr_data;
2287 int stripe;
2288 int pagenr;
2289 int p_stripe = -1;
2290 int q_stripe = -1;
2291 struct page *p_page = NULL;
2292 struct page *q_page = NULL;
2293 struct bio_list bio_list;
2294 struct bio *bio;
2295 int is_replace = 0;
2296 int ret;
2297
2298 bio_list_init(&bio_list);
2299
2300 if (rbio->real_stripes - rbio->nr_data == 1) {
2301 p_stripe = rbio->real_stripes - 1;
2302 } else if (rbio->real_stripes - rbio->nr_data == 2) {
2303 p_stripe = rbio->real_stripes - 2;
2304 q_stripe = rbio->real_stripes - 1;
2305 } else {
2306 BUG();
2307 }
2308
2309 if (bbio->num_tgtdevs && bbio->tgtdev_map[rbio->scrubp]) {
2310 is_replace = 1;
2311 bitmap_copy(pbitmap, rbio->dbitmap, rbio->stripe_npages);
2312 }
2313
2314 /*
2315 * Because the higher layers(scrubber) are unlikely to
2316 * use this area of the disk again soon, so don't cache
2317 * it.
2318 */
2319 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
2320
2321 if (!need_check)
2322 goto writeback;
2323
2324 p_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2325 if (!p_page)
2326 goto cleanup;
2327 SetPageUptodate(p_page);
2328
2329 if (q_stripe != -1) {
2330 q_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2331 if (!q_page) {
2332 __free_page(p_page);
2333 goto cleanup;
2334 }
2335 SetPageUptodate(q_page);
2336 }
2337
2338 atomic_set(&rbio->error, 0);
2339
2340 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2341 struct page *p;
2342 void *parity;
2343 /* first collect one page from each data stripe */
2344 for (stripe = 0; stripe < nr_data; stripe++) {
2345 p = page_in_rbio(rbio, stripe, pagenr, 0);
2346 pointers[stripe] = kmap(p);
2347 }
2348
2349 /* then add the parity stripe */
2350 pointers[stripe++] = kmap(p_page);
2351
2352 if (q_stripe != -1) {
2353
2354 /*
2355 * raid6, add the qstripe and call the
2356 * library function to fill in our p/q
2357 */
2358 pointers[stripe++] = kmap(q_page);
2359
2360 raid6_call.gen_syndrome(rbio->real_stripes, PAGE_SIZE,
2361 pointers);
2362 } else {
2363 /* raid5 */
2364 memcpy(pointers[nr_data], pointers[0], PAGE_SIZE);
2365 run_xor(pointers + 1, nr_data - 1, PAGE_SIZE);
2366 }
2367
2368 /* Check scrubbing parity and repair it */
2369 p = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2370 parity = kmap(p);
2371 if (memcmp(parity, pointers[rbio->scrubp], PAGE_SIZE))
2372 memcpy(parity, pointers[rbio->scrubp], PAGE_SIZE);
2373 else
2374 /* Parity is right, needn't writeback */
2375 bitmap_clear(rbio->dbitmap, pagenr, 1);
2376 kunmap(p);
2377
2378 for (stripe = 0; stripe < rbio->real_stripes; stripe++)
2379 kunmap(page_in_rbio(rbio, stripe, pagenr, 0));
2380 }
2381
2382 __free_page(p_page);
2383 if (q_page)
2384 __free_page(q_page);
2385
2386writeback:
2387 /*
2388 * time to start writing. Make bios for everything from the
2389 * higher layers (the bio_list in our rbio) and our p/q. Ignore
2390 * everything else.
2391 */
2392 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2393 struct page *page;
2394
2395 page = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2396 ret = rbio_add_io_page(rbio, &bio_list,
2397 page, rbio->scrubp, pagenr, rbio->stripe_len);
2398 if (ret)
2399 goto cleanup;
2400 }
2401
2402 if (!is_replace)
2403 goto submit_write;
2404
2405 for_each_set_bit(pagenr, pbitmap, rbio->stripe_npages) {
2406 struct page *page;
2407
2408 page = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2409 ret = rbio_add_io_page(rbio, &bio_list, page,
2410 bbio->tgtdev_map[rbio->scrubp],
2411 pagenr, rbio->stripe_len);
2412 if (ret)
2413 goto cleanup;
2414 }
2415
2416submit_write:
2417 nr_data = bio_list_size(&bio_list);
2418 if (!nr_data) {
2419 /* Every parity is right */
2420 rbio_orig_end_io(rbio, 0);
2421 return;
2422 }
2423
2424 atomic_set(&rbio->stripes_pending, nr_data);
2425
2426 while (1) {
2427 bio = bio_list_pop(&bio_list);
2428 if (!bio)
2429 break;
2430
2431 bio->bi_private = rbio;
2432 bio->bi_end_io = raid_write_end_io;
2433 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
2434
2435 submit_bio(bio);
2436 }
2437 return;
2438
2439cleanup:
2440 rbio_orig_end_io(rbio, -EIO);
2441}
2442
2443static inline int is_data_stripe(struct btrfs_raid_bio *rbio, int stripe)
2444{
2445 if (stripe >= 0 && stripe < rbio->nr_data)
2446 return 1;
2447 return 0;
2448}
2449
2450/*
2451 * While we're doing the parity check and repair, we could have errors
2452 * in reading pages off the disk. This checks for errors and if we're
2453 * not able to read the page it'll trigger parity reconstruction. The
2454 * parity scrub will be finished after we've reconstructed the failed
2455 * stripes
2456 */
2457static void validate_rbio_for_parity_scrub(struct btrfs_raid_bio *rbio)
2458{
2459 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
2460 goto cleanup;
2461
2462 if (rbio->faila >= 0 || rbio->failb >= 0) {
2463 int dfail = 0, failp = -1;
2464
2465 if (is_data_stripe(rbio, rbio->faila))
2466 dfail++;
2467 else if (is_parity_stripe(rbio->faila))
2468 failp = rbio->faila;
2469
2470 if (is_data_stripe(rbio, rbio->failb))
2471 dfail++;
2472 else if (is_parity_stripe(rbio->failb))
2473 failp = rbio->failb;
2474
2475 /*
2476 * Because we can not use a scrubbing parity to repair
2477 * the data, so the capability of the repair is declined.
2478 * (In the case of RAID5, we can not repair anything)
2479 */
2480 if (dfail > rbio->bbio->max_errors - 1)
2481 goto cleanup;
2482
2483 /*
2484 * If all data is good, only parity is correctly, just
2485 * repair the parity.
2486 */
2487 if (dfail == 0) {
2488 finish_parity_scrub(rbio, 0);
2489 return;
2490 }
2491
2492 /*
2493 * Here means we got one corrupted data stripe and one
2494 * corrupted parity on RAID6, if the corrupted parity
2495 * is scrubbing parity, luckily, use the other one to repair
2496 * the data, or we can not repair the data stripe.
2497 */
2498 if (failp != rbio->scrubp)
2499 goto cleanup;
2500
2501 __raid_recover_end_io(rbio);
2502 } else {
2503 finish_parity_scrub(rbio, 1);
2504 }
2505 return;
2506
2507cleanup:
2508 rbio_orig_end_io(rbio, -EIO);
2509}
2510
2511/*
2512 * end io for the read phase of the rmw cycle. All the bios here are physical
2513 * stripe bios we've read from the disk so we can recalculate the parity of the
2514 * stripe.
2515 *
2516 * This will usually kick off finish_rmw once all the bios are read in, but it
2517 * may trigger parity reconstruction if we had any errors along the way
2518 */
2519static void raid56_parity_scrub_end_io(struct bio *bio)
2520{
2521 struct btrfs_raid_bio *rbio = bio->bi_private;
2522
2523 if (bio->bi_error)
2524 fail_bio_stripe(rbio, bio);
2525 else
2526 set_bio_pages_uptodate(bio);
2527
2528 bio_put(bio);
2529
2530 if (!atomic_dec_and_test(&rbio->stripes_pending))
2531 return;
2532
2533 /*
2534 * this will normally call finish_rmw to start our write
2535 * but if there are any failed stripes we'll reconstruct
2536 * from parity first
2537 */
2538 validate_rbio_for_parity_scrub(rbio);
2539}
2540
2541static void raid56_parity_scrub_stripe(struct btrfs_raid_bio *rbio)
2542{
2543 int bios_to_read = 0;
2544 struct bio_list bio_list;
2545 int ret;
2546 int pagenr;
2547 int stripe;
2548 struct bio *bio;
2549
2550 ret = alloc_rbio_essential_pages(rbio);
2551 if (ret)
2552 goto cleanup;
2553
2554 bio_list_init(&bio_list);
2555
2556 atomic_set(&rbio->error, 0);
2557 /*
2558 * build a list of bios to read all the missing parts of this
2559 * stripe
2560 */
2561 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
2562 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2563 struct page *page;
2564 /*
2565 * we want to find all the pages missing from
2566 * the rbio and read them from the disk. If
2567 * page_in_rbio finds a page in the bio list
2568 * we don't need to read it off the stripe.
2569 */
2570 page = page_in_rbio(rbio, stripe, pagenr, 1);
2571 if (page)
2572 continue;
2573
2574 page = rbio_stripe_page(rbio, stripe, pagenr);
2575 /*
2576 * the bio cache may have handed us an uptodate
2577 * page. If so, be happy and use it
2578 */
2579 if (PageUptodate(page))
2580 continue;
2581
2582 ret = rbio_add_io_page(rbio, &bio_list, page,
2583 stripe, pagenr, rbio->stripe_len);
2584 if (ret)
2585 goto cleanup;
2586 }
2587 }
2588
2589 bios_to_read = bio_list_size(&bio_list);
2590 if (!bios_to_read) {
2591 /*
2592 * this can happen if others have merged with
2593 * us, it means there is nothing left to read.
2594 * But if there are missing devices it may not be
2595 * safe to do the full stripe write yet.
2596 */
2597 goto finish;
2598 }
2599
2600 /*
2601 * the bbio may be freed once we submit the last bio. Make sure
2602 * not to touch it after that
2603 */
2604 atomic_set(&rbio->stripes_pending, bios_to_read);
2605 while (1) {
2606 bio = bio_list_pop(&bio_list);
2607 if (!bio)
2608 break;
2609
2610 bio->bi_private = rbio;
2611 bio->bi_end_io = raid56_parity_scrub_end_io;
2612 bio_set_op_attrs(bio, REQ_OP_READ, 0);
2613
2614 btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
2615
2616 submit_bio(bio);
2617 }
2618 /* the actual write will happen once the reads are done */
2619 return;
2620
2621cleanup:
2622 rbio_orig_end_io(rbio, -EIO);
2623 return;
2624
2625finish:
2626 validate_rbio_for_parity_scrub(rbio);
2627}
2628
2629static void scrub_parity_work(struct btrfs_work *work)
2630{
2631 struct btrfs_raid_bio *rbio;
2632
2633 rbio = container_of(work, struct btrfs_raid_bio, work);
2634 raid56_parity_scrub_stripe(rbio);
2635}
2636
2637static void async_scrub_parity(struct btrfs_raid_bio *rbio)
2638{
2639 btrfs_init_work(&rbio->work, btrfs_rmw_helper,
2640 scrub_parity_work, NULL, NULL);
2641
2642 btrfs_queue_work(rbio->fs_info->rmw_workers, &rbio->work);
2643}
2644
2645void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio)
2646{
2647 if (!lock_stripe_add(rbio))
2648 async_scrub_parity(rbio);
2649}
2650
2651/* The following code is used for dev replace of a missing RAID 5/6 device. */
2652
2653struct btrfs_raid_bio *
2654raid56_alloc_missing_rbio(struct btrfs_fs_info *fs_info, struct bio *bio,
2655 struct btrfs_bio *bbio, u64 length)
2656{
2657 struct btrfs_raid_bio *rbio;
2658
2659 rbio = alloc_rbio(fs_info, bbio, length);
2660 if (IS_ERR(rbio))
2661 return NULL;
2662
2663 rbio->operation = BTRFS_RBIO_REBUILD_MISSING;
2664 bio_list_add(&rbio->bio_list, bio);
2665 /*
2666 * This is a special bio which is used to hold the completion handler
2667 * and make the scrub rbio is similar to the other types
2668 */
2669 ASSERT(!bio->bi_iter.bi_size);
2670
2671 rbio->faila = find_logical_bio_stripe(rbio, bio);
2672 if (rbio->faila == -1) {
2673 BUG();
2674 kfree(rbio);
2675 return NULL;
2676 }
2677
2678 return rbio;
2679}
2680
2681static void missing_raid56_work(struct btrfs_work *work)
2682{
2683 struct btrfs_raid_bio *rbio;
2684
2685 rbio = container_of(work, struct btrfs_raid_bio, work);
2686 __raid56_parity_recover(rbio);
2687}
2688
2689static void async_missing_raid56(struct btrfs_raid_bio *rbio)
2690{
2691 btrfs_init_work(&rbio->work, btrfs_rmw_helper,
2692 missing_raid56_work, NULL, NULL);
2693
2694 btrfs_queue_work(rbio->fs_info->rmw_workers, &rbio->work);
2695}
2696
2697void raid56_submit_missing_rbio(struct btrfs_raid_bio *rbio)
2698{
2699 if (!lock_stripe_add(rbio))
2700 async_missing_raid56(rbio);
2701}