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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2012 Fusion-io All rights reserved.
4 * Copyright (C) 2012 Intel Corp. All rights reserved.
5 */
6
7#include <linux/sched.h>
8#include <linux/bio.h>
9#include <linux/slab.h>
10#include <linux/blkdev.h>
11#include <linux/raid/pq.h>
12#include <linux/hash.h>
13#include <linux/list_sort.h>
14#include <linux/raid/xor.h>
15#include <linux/mm.h>
16#include "misc.h"
17#include "ctree.h"
18#include "disk-io.h"
19#include "volumes.h"
20#include "raid56.h"
21#include "async-thread.h"
22
23/* set when additional merges to this rbio are not allowed */
24#define RBIO_RMW_LOCKED_BIT 1
25
26/*
27 * set when this rbio is sitting in the hash, but it is just a cache
28 * of past RMW
29 */
30#define RBIO_CACHE_BIT 2
31
32/*
33 * set when it is safe to trust the stripe_pages for caching
34 */
35#define RBIO_CACHE_READY_BIT 3
36
37#define RBIO_CACHE_SIZE 1024
38
39#define BTRFS_STRIPE_HASH_TABLE_BITS 11
40
41/* Used by the raid56 code to lock stripes for read/modify/write */
42struct btrfs_stripe_hash {
43 struct list_head hash_list;
44 spinlock_t lock;
45};
46
47/* Used by the raid56 code to lock stripes for read/modify/write */
48struct btrfs_stripe_hash_table {
49 struct list_head stripe_cache;
50 spinlock_t cache_lock;
51 int cache_size;
52 struct btrfs_stripe_hash table[];
53};
54
55enum btrfs_rbio_ops {
56 BTRFS_RBIO_WRITE,
57 BTRFS_RBIO_READ_REBUILD,
58 BTRFS_RBIO_PARITY_SCRUB,
59 BTRFS_RBIO_REBUILD_MISSING,
60};
61
62struct btrfs_raid_bio {
63 struct btrfs_fs_info *fs_info;
64 struct btrfs_bio *bbio;
65
66 /* while we're doing rmw on a stripe
67 * we put it into a hash table so we can
68 * lock the stripe and merge more rbios
69 * into it.
70 */
71 struct list_head hash_list;
72
73 /*
74 * LRU list for the stripe cache
75 */
76 struct list_head stripe_cache;
77
78 /*
79 * for scheduling work in the helper threads
80 */
81 struct btrfs_work work;
82
83 /*
84 * bio list and bio_list_lock are used
85 * to add more bios into the stripe
86 * in hopes of avoiding the full rmw
87 */
88 struct bio_list bio_list;
89 spinlock_t bio_list_lock;
90
91 /* also protected by the bio_list_lock, the
92 * plug list is used by the plugging code
93 * to collect partial bios while plugged. The
94 * stripe locking code also uses it to hand off
95 * the stripe lock to the next pending IO
96 */
97 struct list_head plug_list;
98
99 /*
100 * flags that tell us if it is safe to
101 * merge with this bio
102 */
103 unsigned long flags;
104
105 /* size of each individual stripe on disk */
106 int stripe_len;
107
108 /* number of data stripes (no p/q) */
109 int nr_data;
110
111 int real_stripes;
112
113 int stripe_npages;
114 /*
115 * set if we're doing a parity rebuild
116 * for a read from higher up, which is handled
117 * differently from a parity rebuild as part of
118 * rmw
119 */
120 enum btrfs_rbio_ops operation;
121
122 /* first bad stripe */
123 int faila;
124
125 /* second bad stripe (for raid6 use) */
126 int failb;
127
128 int scrubp;
129 /*
130 * number of pages needed to represent the full
131 * stripe
132 */
133 int nr_pages;
134
135 /*
136 * size of all the bios in the bio_list. This
137 * helps us decide if the rbio maps to a full
138 * stripe or not
139 */
140 int bio_list_bytes;
141
142 int generic_bio_cnt;
143
144 refcount_t refs;
145
146 atomic_t stripes_pending;
147
148 atomic_t error;
149 /*
150 * these are two arrays of pointers. We allocate the
151 * rbio big enough to hold them both and setup their
152 * locations when the rbio is allocated
153 */
154
155 /* pointers to pages that we allocated for
156 * reading/writing stripes directly from the disk (including P/Q)
157 */
158 struct page **stripe_pages;
159
160 /*
161 * pointers to the pages in the bio_list. Stored
162 * here for faster lookup
163 */
164 struct page **bio_pages;
165
166 /*
167 * bitmap to record which horizontal stripe has data
168 */
169 unsigned long *dbitmap;
170
171 /* allocated with real_stripes-many pointers for finish_*() calls */
172 void **finish_pointers;
173
174 /* allocated with stripe_npages-many bits for finish_*() calls */
175 unsigned long *finish_pbitmap;
176};
177
178static int __raid56_parity_recover(struct btrfs_raid_bio *rbio);
179static noinline void finish_rmw(struct btrfs_raid_bio *rbio);
180static void rmw_work(struct btrfs_work *work);
181static void read_rebuild_work(struct btrfs_work *work);
182static int fail_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio);
183static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed);
184static void __free_raid_bio(struct btrfs_raid_bio *rbio);
185static void index_rbio_pages(struct btrfs_raid_bio *rbio);
186static int alloc_rbio_pages(struct btrfs_raid_bio *rbio);
187
188static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
189 int need_check);
190static void scrub_parity_work(struct btrfs_work *work);
191
192static void start_async_work(struct btrfs_raid_bio *rbio, btrfs_func_t work_func)
193{
194 btrfs_init_work(&rbio->work, work_func, NULL, NULL);
195 btrfs_queue_work(rbio->fs_info->rmw_workers, &rbio->work);
196}
197
198/*
199 * the stripe hash table is used for locking, and to collect
200 * bios in hopes of making a full stripe
201 */
202int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info)
203{
204 struct btrfs_stripe_hash_table *table;
205 struct btrfs_stripe_hash_table *x;
206 struct btrfs_stripe_hash *cur;
207 struct btrfs_stripe_hash *h;
208 int num_entries = 1 << BTRFS_STRIPE_HASH_TABLE_BITS;
209 int i;
210
211 if (info->stripe_hash_table)
212 return 0;
213
214 /*
215 * The table is large, starting with order 4 and can go as high as
216 * order 7 in case lock debugging is turned on.
217 *
218 * Try harder to allocate and fallback to vmalloc to lower the chance
219 * of a failing mount.
220 */
221 table = kvzalloc(struct_size(table, table, num_entries), GFP_KERNEL);
222 if (!table)
223 return -ENOMEM;
224
225 spin_lock_init(&table->cache_lock);
226 INIT_LIST_HEAD(&table->stripe_cache);
227
228 h = table->table;
229
230 for (i = 0; i < num_entries; i++) {
231 cur = h + i;
232 INIT_LIST_HEAD(&cur->hash_list);
233 spin_lock_init(&cur->lock);
234 }
235
236 x = cmpxchg(&info->stripe_hash_table, NULL, table);
237 kvfree(x);
238 return 0;
239}
240
241/*
242 * caching an rbio means to copy anything from the
243 * bio_pages array into the stripe_pages array. We
244 * use the page uptodate bit in the stripe cache array
245 * to indicate if it has valid data
246 *
247 * once the caching is done, we set the cache ready
248 * bit.
249 */
250static void cache_rbio_pages(struct btrfs_raid_bio *rbio)
251{
252 int i;
253 int ret;
254
255 ret = alloc_rbio_pages(rbio);
256 if (ret)
257 return;
258
259 for (i = 0; i < rbio->nr_pages; i++) {
260 if (!rbio->bio_pages[i])
261 continue;
262
263 copy_highpage(rbio->stripe_pages[i], rbio->bio_pages[i]);
264 SetPageUptodate(rbio->stripe_pages[i]);
265 }
266 set_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
267}
268
269/*
270 * we hash on the first logical address of the stripe
271 */
272static int rbio_bucket(struct btrfs_raid_bio *rbio)
273{
274 u64 num = rbio->bbio->raid_map[0];
275
276 /*
277 * we shift down quite a bit. We're using byte
278 * addressing, and most of the lower bits are zeros.
279 * This tends to upset hash_64, and it consistently
280 * returns just one or two different values.
281 *
282 * shifting off the lower bits fixes things.
283 */
284 return hash_64(num >> 16, BTRFS_STRIPE_HASH_TABLE_BITS);
285}
286
287/*
288 * stealing an rbio means taking all the uptodate pages from the stripe
289 * array in the source rbio and putting them into the destination rbio
290 */
291static void steal_rbio(struct btrfs_raid_bio *src, struct btrfs_raid_bio *dest)
292{
293 int i;
294 struct page *s;
295 struct page *d;
296
297 if (!test_bit(RBIO_CACHE_READY_BIT, &src->flags))
298 return;
299
300 for (i = 0; i < dest->nr_pages; i++) {
301 s = src->stripe_pages[i];
302 if (!s || !PageUptodate(s)) {
303 continue;
304 }
305
306 d = dest->stripe_pages[i];
307 if (d)
308 __free_page(d);
309
310 dest->stripe_pages[i] = s;
311 src->stripe_pages[i] = NULL;
312 }
313}
314
315/*
316 * merging means we take the bio_list from the victim and
317 * splice it into the destination. The victim should
318 * be discarded afterwards.
319 *
320 * must be called with dest->rbio_list_lock held
321 */
322static void merge_rbio(struct btrfs_raid_bio *dest,
323 struct btrfs_raid_bio *victim)
324{
325 bio_list_merge(&dest->bio_list, &victim->bio_list);
326 dest->bio_list_bytes += victim->bio_list_bytes;
327 dest->generic_bio_cnt += victim->generic_bio_cnt;
328 bio_list_init(&victim->bio_list);
329}
330
331/*
332 * used to prune items that are in the cache. The caller
333 * must hold the hash table lock.
334 */
335static void __remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
336{
337 int bucket = rbio_bucket(rbio);
338 struct btrfs_stripe_hash_table *table;
339 struct btrfs_stripe_hash *h;
340 int freeit = 0;
341
342 /*
343 * check the bit again under the hash table lock.
344 */
345 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
346 return;
347
348 table = rbio->fs_info->stripe_hash_table;
349 h = table->table + bucket;
350
351 /* hold the lock for the bucket because we may be
352 * removing it from the hash table
353 */
354 spin_lock(&h->lock);
355
356 /*
357 * hold the lock for the bio list because we need
358 * to make sure the bio list is empty
359 */
360 spin_lock(&rbio->bio_list_lock);
361
362 if (test_and_clear_bit(RBIO_CACHE_BIT, &rbio->flags)) {
363 list_del_init(&rbio->stripe_cache);
364 table->cache_size -= 1;
365 freeit = 1;
366
367 /* if the bio list isn't empty, this rbio is
368 * still involved in an IO. We take it out
369 * of the cache list, and drop the ref that
370 * was held for the list.
371 *
372 * If the bio_list was empty, we also remove
373 * the rbio from the hash_table, and drop
374 * the corresponding ref
375 */
376 if (bio_list_empty(&rbio->bio_list)) {
377 if (!list_empty(&rbio->hash_list)) {
378 list_del_init(&rbio->hash_list);
379 refcount_dec(&rbio->refs);
380 BUG_ON(!list_empty(&rbio->plug_list));
381 }
382 }
383 }
384
385 spin_unlock(&rbio->bio_list_lock);
386 spin_unlock(&h->lock);
387
388 if (freeit)
389 __free_raid_bio(rbio);
390}
391
392/*
393 * prune a given rbio from the cache
394 */
395static void remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
396{
397 struct btrfs_stripe_hash_table *table;
398 unsigned long flags;
399
400 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
401 return;
402
403 table = rbio->fs_info->stripe_hash_table;
404
405 spin_lock_irqsave(&table->cache_lock, flags);
406 __remove_rbio_from_cache(rbio);
407 spin_unlock_irqrestore(&table->cache_lock, flags);
408}
409
410/*
411 * remove everything in the cache
412 */
413static void btrfs_clear_rbio_cache(struct btrfs_fs_info *info)
414{
415 struct btrfs_stripe_hash_table *table;
416 unsigned long flags;
417 struct btrfs_raid_bio *rbio;
418
419 table = info->stripe_hash_table;
420
421 spin_lock_irqsave(&table->cache_lock, flags);
422 while (!list_empty(&table->stripe_cache)) {
423 rbio = list_entry(table->stripe_cache.next,
424 struct btrfs_raid_bio,
425 stripe_cache);
426 __remove_rbio_from_cache(rbio);
427 }
428 spin_unlock_irqrestore(&table->cache_lock, flags);
429}
430
431/*
432 * remove all cached entries and free the hash table
433 * used by unmount
434 */
435void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info)
436{
437 if (!info->stripe_hash_table)
438 return;
439 btrfs_clear_rbio_cache(info);
440 kvfree(info->stripe_hash_table);
441 info->stripe_hash_table = NULL;
442}
443
444/*
445 * insert an rbio into the stripe cache. It
446 * must have already been prepared by calling
447 * cache_rbio_pages
448 *
449 * If this rbio was already cached, it gets
450 * moved to the front of the lru.
451 *
452 * If the size of the rbio cache is too big, we
453 * prune an item.
454 */
455static void cache_rbio(struct btrfs_raid_bio *rbio)
456{
457 struct btrfs_stripe_hash_table *table;
458 unsigned long flags;
459
460 if (!test_bit(RBIO_CACHE_READY_BIT, &rbio->flags))
461 return;
462
463 table = rbio->fs_info->stripe_hash_table;
464
465 spin_lock_irqsave(&table->cache_lock, flags);
466 spin_lock(&rbio->bio_list_lock);
467
468 /* bump our ref if we were not in the list before */
469 if (!test_and_set_bit(RBIO_CACHE_BIT, &rbio->flags))
470 refcount_inc(&rbio->refs);
471
472 if (!list_empty(&rbio->stripe_cache)){
473 list_move(&rbio->stripe_cache, &table->stripe_cache);
474 } else {
475 list_add(&rbio->stripe_cache, &table->stripe_cache);
476 table->cache_size += 1;
477 }
478
479 spin_unlock(&rbio->bio_list_lock);
480
481 if (table->cache_size > RBIO_CACHE_SIZE) {
482 struct btrfs_raid_bio *found;
483
484 found = list_entry(table->stripe_cache.prev,
485 struct btrfs_raid_bio,
486 stripe_cache);
487
488 if (found != rbio)
489 __remove_rbio_from_cache(found);
490 }
491
492 spin_unlock_irqrestore(&table->cache_lock, flags);
493}
494
495/*
496 * helper function to run the xor_blocks api. It is only
497 * able to do MAX_XOR_BLOCKS at a time, so we need to
498 * loop through.
499 */
500static void run_xor(void **pages, int src_cnt, ssize_t len)
501{
502 int src_off = 0;
503 int xor_src_cnt = 0;
504 void *dest = pages[src_cnt];
505
506 while(src_cnt > 0) {
507 xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS);
508 xor_blocks(xor_src_cnt, len, dest, pages + src_off);
509
510 src_cnt -= xor_src_cnt;
511 src_off += xor_src_cnt;
512 }
513}
514
515/*
516 * Returns true if the bio list inside this rbio covers an entire stripe (no
517 * rmw required).
518 */
519static int rbio_is_full(struct btrfs_raid_bio *rbio)
520{
521 unsigned long flags;
522 unsigned long size = rbio->bio_list_bytes;
523 int ret = 1;
524
525 spin_lock_irqsave(&rbio->bio_list_lock, flags);
526 if (size != rbio->nr_data * rbio->stripe_len)
527 ret = 0;
528 BUG_ON(size > rbio->nr_data * rbio->stripe_len);
529 spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
530
531 return ret;
532}
533
534/*
535 * returns 1 if it is safe to merge two rbios together.
536 * The merging is safe if the two rbios correspond to
537 * the same stripe and if they are both going in the same
538 * direction (read vs write), and if neither one is
539 * locked for final IO
540 *
541 * The caller is responsible for locking such that
542 * rmw_locked is safe to test
543 */
544static int rbio_can_merge(struct btrfs_raid_bio *last,
545 struct btrfs_raid_bio *cur)
546{
547 if (test_bit(RBIO_RMW_LOCKED_BIT, &last->flags) ||
548 test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags))
549 return 0;
550
551 /*
552 * we can't merge with cached rbios, since the
553 * idea is that when we merge the destination
554 * rbio is going to run our IO for us. We can
555 * steal from cached rbios though, other functions
556 * handle that.
557 */
558 if (test_bit(RBIO_CACHE_BIT, &last->flags) ||
559 test_bit(RBIO_CACHE_BIT, &cur->flags))
560 return 0;
561
562 if (last->bbio->raid_map[0] !=
563 cur->bbio->raid_map[0])
564 return 0;
565
566 /* we can't merge with different operations */
567 if (last->operation != cur->operation)
568 return 0;
569 /*
570 * We've need read the full stripe from the drive.
571 * check and repair the parity and write the new results.
572 *
573 * We're not allowed to add any new bios to the
574 * bio list here, anyone else that wants to
575 * change this stripe needs to do their own rmw.
576 */
577 if (last->operation == BTRFS_RBIO_PARITY_SCRUB)
578 return 0;
579
580 if (last->operation == BTRFS_RBIO_REBUILD_MISSING)
581 return 0;
582
583 if (last->operation == BTRFS_RBIO_READ_REBUILD) {
584 int fa = last->faila;
585 int fb = last->failb;
586 int cur_fa = cur->faila;
587 int cur_fb = cur->failb;
588
589 if (last->faila >= last->failb) {
590 fa = last->failb;
591 fb = last->faila;
592 }
593
594 if (cur->faila >= cur->failb) {
595 cur_fa = cur->failb;
596 cur_fb = cur->faila;
597 }
598
599 if (fa != cur_fa || fb != cur_fb)
600 return 0;
601 }
602 return 1;
603}
604
605static int rbio_stripe_page_index(struct btrfs_raid_bio *rbio, int stripe,
606 int index)
607{
608 return stripe * rbio->stripe_npages + index;
609}
610
611/*
612 * these are just the pages from the rbio array, not from anything
613 * the FS sent down to us
614 */
615static struct page *rbio_stripe_page(struct btrfs_raid_bio *rbio, int stripe,
616 int index)
617{
618 return rbio->stripe_pages[rbio_stripe_page_index(rbio, stripe, index)];
619}
620
621/*
622 * helper to index into the pstripe
623 */
624static struct page *rbio_pstripe_page(struct btrfs_raid_bio *rbio, int index)
625{
626 return rbio_stripe_page(rbio, rbio->nr_data, index);
627}
628
629/*
630 * helper to index into the qstripe, returns null
631 * if there is no qstripe
632 */
633static struct page *rbio_qstripe_page(struct btrfs_raid_bio *rbio, int index)
634{
635 if (rbio->nr_data + 1 == rbio->real_stripes)
636 return NULL;
637 return rbio_stripe_page(rbio, rbio->nr_data + 1, index);
638}
639
640/*
641 * The first stripe in the table for a logical address
642 * has the lock. rbios are added in one of three ways:
643 *
644 * 1) Nobody has the stripe locked yet. The rbio is given
645 * the lock and 0 is returned. The caller must start the IO
646 * themselves.
647 *
648 * 2) Someone has the stripe locked, but we're able to merge
649 * with the lock owner. The rbio is freed and the IO will
650 * start automatically along with the existing rbio. 1 is returned.
651 *
652 * 3) Someone has the stripe locked, but we're not able to merge.
653 * The rbio is added to the lock owner's plug list, or merged into
654 * an rbio already on the plug list. When the lock owner unlocks,
655 * the next rbio on the list is run and the IO is started automatically.
656 * 1 is returned
657 *
658 * If we return 0, the caller still owns the rbio and must continue with
659 * IO submission. If we return 1, the caller must assume the rbio has
660 * already been freed.
661 */
662static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
663{
664 struct btrfs_stripe_hash *h;
665 struct btrfs_raid_bio *cur;
666 struct btrfs_raid_bio *pending;
667 unsigned long flags;
668 struct btrfs_raid_bio *freeit = NULL;
669 struct btrfs_raid_bio *cache_drop = NULL;
670 int ret = 0;
671
672 h = rbio->fs_info->stripe_hash_table->table + rbio_bucket(rbio);
673
674 spin_lock_irqsave(&h->lock, flags);
675 list_for_each_entry(cur, &h->hash_list, hash_list) {
676 if (cur->bbio->raid_map[0] != rbio->bbio->raid_map[0])
677 continue;
678
679 spin_lock(&cur->bio_list_lock);
680
681 /* Can we steal this cached rbio's pages? */
682 if (bio_list_empty(&cur->bio_list) &&
683 list_empty(&cur->plug_list) &&
684 test_bit(RBIO_CACHE_BIT, &cur->flags) &&
685 !test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) {
686 list_del_init(&cur->hash_list);
687 refcount_dec(&cur->refs);
688
689 steal_rbio(cur, rbio);
690 cache_drop = cur;
691 spin_unlock(&cur->bio_list_lock);
692
693 goto lockit;
694 }
695
696 /* Can we merge into the lock owner? */
697 if (rbio_can_merge(cur, rbio)) {
698 merge_rbio(cur, rbio);
699 spin_unlock(&cur->bio_list_lock);
700 freeit = rbio;
701 ret = 1;
702 goto out;
703 }
704
705
706 /*
707 * We couldn't merge with the running rbio, see if we can merge
708 * with the pending ones. We don't have to check for rmw_locked
709 * because there is no way they are inside finish_rmw right now
710 */
711 list_for_each_entry(pending, &cur->plug_list, plug_list) {
712 if (rbio_can_merge(pending, rbio)) {
713 merge_rbio(pending, rbio);
714 spin_unlock(&cur->bio_list_lock);
715 freeit = rbio;
716 ret = 1;
717 goto out;
718 }
719 }
720
721 /*
722 * No merging, put us on the tail of the plug list, our rbio
723 * will be started with the currently running rbio unlocks
724 */
725 list_add_tail(&rbio->plug_list, &cur->plug_list);
726 spin_unlock(&cur->bio_list_lock);
727 ret = 1;
728 goto out;
729 }
730lockit:
731 refcount_inc(&rbio->refs);
732 list_add(&rbio->hash_list, &h->hash_list);
733out:
734 spin_unlock_irqrestore(&h->lock, flags);
735 if (cache_drop)
736 remove_rbio_from_cache(cache_drop);
737 if (freeit)
738 __free_raid_bio(freeit);
739 return ret;
740}
741
742/*
743 * called as rmw or parity rebuild is completed. If the plug list has more
744 * rbios waiting for this stripe, the next one on the list will be started
745 */
746static noinline void unlock_stripe(struct btrfs_raid_bio *rbio)
747{
748 int bucket;
749 struct btrfs_stripe_hash *h;
750 unsigned long flags;
751 int keep_cache = 0;
752
753 bucket = rbio_bucket(rbio);
754 h = rbio->fs_info->stripe_hash_table->table + bucket;
755
756 if (list_empty(&rbio->plug_list))
757 cache_rbio(rbio);
758
759 spin_lock_irqsave(&h->lock, flags);
760 spin_lock(&rbio->bio_list_lock);
761
762 if (!list_empty(&rbio->hash_list)) {
763 /*
764 * if we're still cached and there is no other IO
765 * to perform, just leave this rbio here for others
766 * to steal from later
767 */
768 if (list_empty(&rbio->plug_list) &&
769 test_bit(RBIO_CACHE_BIT, &rbio->flags)) {
770 keep_cache = 1;
771 clear_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
772 BUG_ON(!bio_list_empty(&rbio->bio_list));
773 goto done;
774 }
775
776 list_del_init(&rbio->hash_list);
777 refcount_dec(&rbio->refs);
778
779 /*
780 * we use the plug list to hold all the rbios
781 * waiting for the chance to lock this stripe.
782 * hand the lock over to one of them.
783 */
784 if (!list_empty(&rbio->plug_list)) {
785 struct btrfs_raid_bio *next;
786 struct list_head *head = rbio->plug_list.next;
787
788 next = list_entry(head, struct btrfs_raid_bio,
789 plug_list);
790
791 list_del_init(&rbio->plug_list);
792
793 list_add(&next->hash_list, &h->hash_list);
794 refcount_inc(&next->refs);
795 spin_unlock(&rbio->bio_list_lock);
796 spin_unlock_irqrestore(&h->lock, flags);
797
798 if (next->operation == BTRFS_RBIO_READ_REBUILD)
799 start_async_work(next, read_rebuild_work);
800 else if (next->operation == BTRFS_RBIO_REBUILD_MISSING) {
801 steal_rbio(rbio, next);
802 start_async_work(next, read_rebuild_work);
803 } else if (next->operation == BTRFS_RBIO_WRITE) {
804 steal_rbio(rbio, next);
805 start_async_work(next, rmw_work);
806 } else if (next->operation == BTRFS_RBIO_PARITY_SCRUB) {
807 steal_rbio(rbio, next);
808 start_async_work(next, scrub_parity_work);
809 }
810
811 goto done_nolock;
812 }
813 }
814done:
815 spin_unlock(&rbio->bio_list_lock);
816 spin_unlock_irqrestore(&h->lock, flags);
817
818done_nolock:
819 if (!keep_cache)
820 remove_rbio_from_cache(rbio);
821}
822
823static void __free_raid_bio(struct btrfs_raid_bio *rbio)
824{
825 int i;
826
827 if (!refcount_dec_and_test(&rbio->refs))
828 return;
829
830 WARN_ON(!list_empty(&rbio->stripe_cache));
831 WARN_ON(!list_empty(&rbio->hash_list));
832 WARN_ON(!bio_list_empty(&rbio->bio_list));
833
834 for (i = 0; i < rbio->nr_pages; i++) {
835 if (rbio->stripe_pages[i]) {
836 __free_page(rbio->stripe_pages[i]);
837 rbio->stripe_pages[i] = NULL;
838 }
839 }
840
841 btrfs_put_bbio(rbio->bbio);
842 kfree(rbio);
843}
844
845static void rbio_endio_bio_list(struct bio *cur, blk_status_t err)
846{
847 struct bio *next;
848
849 while (cur) {
850 next = cur->bi_next;
851 cur->bi_next = NULL;
852 cur->bi_status = err;
853 bio_endio(cur);
854 cur = next;
855 }
856}
857
858/*
859 * this frees the rbio and runs through all the bios in the
860 * bio_list and calls end_io on them
861 */
862static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, blk_status_t err)
863{
864 struct bio *cur = bio_list_get(&rbio->bio_list);
865 struct bio *extra;
866
867 if (rbio->generic_bio_cnt)
868 btrfs_bio_counter_sub(rbio->fs_info, rbio->generic_bio_cnt);
869
870 /*
871 * At this moment, rbio->bio_list is empty, however since rbio does not
872 * always have RBIO_RMW_LOCKED_BIT set and rbio is still linked on the
873 * hash list, rbio may be merged with others so that rbio->bio_list
874 * becomes non-empty.
875 * Once unlock_stripe() is done, rbio->bio_list will not be updated any
876 * more and we can call bio_endio() on all queued bios.
877 */
878 unlock_stripe(rbio);
879 extra = bio_list_get(&rbio->bio_list);
880 __free_raid_bio(rbio);
881
882 rbio_endio_bio_list(cur, err);
883 if (extra)
884 rbio_endio_bio_list(extra, err);
885}
886
887/*
888 * end io function used by finish_rmw. When we finally
889 * get here, we've written a full stripe
890 */
891static void raid_write_end_io(struct bio *bio)
892{
893 struct btrfs_raid_bio *rbio = bio->bi_private;
894 blk_status_t err = bio->bi_status;
895 int max_errors;
896
897 if (err)
898 fail_bio_stripe(rbio, bio);
899
900 bio_put(bio);
901
902 if (!atomic_dec_and_test(&rbio->stripes_pending))
903 return;
904
905 err = BLK_STS_OK;
906
907 /* OK, we have read all the stripes we need to. */
908 max_errors = (rbio->operation == BTRFS_RBIO_PARITY_SCRUB) ?
909 0 : rbio->bbio->max_errors;
910 if (atomic_read(&rbio->error) > max_errors)
911 err = BLK_STS_IOERR;
912
913 rbio_orig_end_io(rbio, err);
914}
915
916/*
917 * the read/modify/write code wants to use the original bio for
918 * any pages it included, and then use the rbio for everything
919 * else. This function decides if a given index (stripe number)
920 * and page number in that stripe fall inside the original bio
921 * or the rbio.
922 *
923 * if you set bio_list_only, you'll get a NULL back for any ranges
924 * that are outside the bio_list
925 *
926 * This doesn't take any refs on anything, you get a bare page pointer
927 * and the caller must bump refs as required.
928 *
929 * You must call index_rbio_pages once before you can trust
930 * the answers from this function.
931 */
932static struct page *page_in_rbio(struct btrfs_raid_bio *rbio,
933 int index, int pagenr, int bio_list_only)
934{
935 int chunk_page;
936 struct page *p = NULL;
937
938 chunk_page = index * (rbio->stripe_len >> PAGE_SHIFT) + pagenr;
939
940 spin_lock_irq(&rbio->bio_list_lock);
941 p = rbio->bio_pages[chunk_page];
942 spin_unlock_irq(&rbio->bio_list_lock);
943
944 if (p || bio_list_only)
945 return p;
946
947 return rbio->stripe_pages[chunk_page];
948}
949
950/*
951 * number of pages we need for the entire stripe across all the
952 * drives
953 */
954static unsigned long rbio_nr_pages(unsigned long stripe_len, int nr_stripes)
955{
956 return DIV_ROUND_UP(stripe_len, PAGE_SIZE) * nr_stripes;
957}
958
959/*
960 * allocation and initial setup for the btrfs_raid_bio. Not
961 * this does not allocate any pages for rbio->pages.
962 */
963static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info,
964 struct btrfs_bio *bbio,
965 u64 stripe_len)
966{
967 struct btrfs_raid_bio *rbio;
968 int nr_data = 0;
969 int real_stripes = bbio->num_stripes - bbio->num_tgtdevs;
970 int num_pages = rbio_nr_pages(stripe_len, real_stripes);
971 int stripe_npages = DIV_ROUND_UP(stripe_len, PAGE_SIZE);
972 void *p;
973
974 rbio = kzalloc(sizeof(*rbio) +
975 sizeof(*rbio->stripe_pages) * num_pages +
976 sizeof(*rbio->bio_pages) * num_pages +
977 sizeof(*rbio->finish_pointers) * real_stripes +
978 sizeof(*rbio->dbitmap) * BITS_TO_LONGS(stripe_npages) +
979 sizeof(*rbio->finish_pbitmap) *
980 BITS_TO_LONGS(stripe_npages),
981 GFP_NOFS);
982 if (!rbio)
983 return ERR_PTR(-ENOMEM);
984
985 bio_list_init(&rbio->bio_list);
986 INIT_LIST_HEAD(&rbio->plug_list);
987 spin_lock_init(&rbio->bio_list_lock);
988 INIT_LIST_HEAD(&rbio->stripe_cache);
989 INIT_LIST_HEAD(&rbio->hash_list);
990 rbio->bbio = bbio;
991 rbio->fs_info = fs_info;
992 rbio->stripe_len = stripe_len;
993 rbio->nr_pages = num_pages;
994 rbio->real_stripes = real_stripes;
995 rbio->stripe_npages = stripe_npages;
996 rbio->faila = -1;
997 rbio->failb = -1;
998 refcount_set(&rbio->refs, 1);
999 atomic_set(&rbio->error, 0);
1000 atomic_set(&rbio->stripes_pending, 0);
1001
1002 /*
1003 * the stripe_pages, bio_pages, etc arrays point to the extra
1004 * memory we allocated past the end of the rbio
1005 */
1006 p = rbio + 1;
1007#define CONSUME_ALLOC(ptr, count) do { \
1008 ptr = p; \
1009 p = (unsigned char *)p + sizeof(*(ptr)) * (count); \
1010 } while (0)
1011 CONSUME_ALLOC(rbio->stripe_pages, num_pages);
1012 CONSUME_ALLOC(rbio->bio_pages, num_pages);
1013 CONSUME_ALLOC(rbio->finish_pointers, real_stripes);
1014 CONSUME_ALLOC(rbio->dbitmap, BITS_TO_LONGS(stripe_npages));
1015 CONSUME_ALLOC(rbio->finish_pbitmap, BITS_TO_LONGS(stripe_npages));
1016#undef CONSUME_ALLOC
1017
1018 if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID5)
1019 nr_data = real_stripes - 1;
1020 else if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID6)
1021 nr_data = real_stripes - 2;
1022 else
1023 BUG();
1024
1025 rbio->nr_data = nr_data;
1026 return rbio;
1027}
1028
1029/* allocate pages for all the stripes in the bio, including parity */
1030static int alloc_rbio_pages(struct btrfs_raid_bio *rbio)
1031{
1032 int i;
1033 struct page *page;
1034
1035 for (i = 0; i < rbio->nr_pages; i++) {
1036 if (rbio->stripe_pages[i])
1037 continue;
1038 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1039 if (!page)
1040 return -ENOMEM;
1041 rbio->stripe_pages[i] = page;
1042 }
1043 return 0;
1044}
1045
1046/* only allocate pages for p/q stripes */
1047static int alloc_rbio_parity_pages(struct btrfs_raid_bio *rbio)
1048{
1049 int i;
1050 struct page *page;
1051
1052 i = rbio_stripe_page_index(rbio, rbio->nr_data, 0);
1053
1054 for (; i < rbio->nr_pages; i++) {
1055 if (rbio->stripe_pages[i])
1056 continue;
1057 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1058 if (!page)
1059 return -ENOMEM;
1060 rbio->stripe_pages[i] = page;
1061 }
1062 return 0;
1063}
1064
1065/*
1066 * add a single page from a specific stripe into our list of bios for IO
1067 * this will try to merge into existing bios if possible, and returns
1068 * zero if all went well.
1069 */
1070static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
1071 struct bio_list *bio_list,
1072 struct page *page,
1073 int stripe_nr,
1074 unsigned long page_index,
1075 unsigned long bio_max_len)
1076{
1077 struct bio *last = bio_list->tail;
1078 int ret;
1079 struct bio *bio;
1080 struct btrfs_bio_stripe *stripe;
1081 u64 disk_start;
1082
1083 stripe = &rbio->bbio->stripes[stripe_nr];
1084 disk_start = stripe->physical + (page_index << PAGE_SHIFT);
1085
1086 /* if the device is missing, just fail this stripe */
1087 if (!stripe->dev->bdev)
1088 return fail_rbio_index(rbio, stripe_nr);
1089
1090 /* see if we can add this page onto our existing bio */
1091 if (last) {
1092 u64 last_end = last->bi_iter.bi_sector << 9;
1093 last_end += last->bi_iter.bi_size;
1094
1095 /*
1096 * we can't merge these if they are from different
1097 * devices or if they are not contiguous
1098 */
1099 if (last_end == disk_start && !last->bi_status &&
1100 last->bi_bdev == stripe->dev->bdev) {
1101 ret = bio_add_page(last, page, PAGE_SIZE, 0);
1102 if (ret == PAGE_SIZE)
1103 return 0;
1104 }
1105 }
1106
1107 /* put a new bio on the list */
1108 bio = btrfs_io_bio_alloc(bio_max_len >> PAGE_SHIFT ?: 1);
1109 btrfs_io_bio(bio)->device = stripe->dev;
1110 bio->bi_iter.bi_size = 0;
1111 bio_set_dev(bio, stripe->dev->bdev);
1112 bio->bi_iter.bi_sector = disk_start >> 9;
1113
1114 bio_add_page(bio, page, PAGE_SIZE, 0);
1115 bio_list_add(bio_list, bio);
1116 return 0;
1117}
1118
1119/*
1120 * while we're doing the read/modify/write cycle, we could
1121 * have errors in reading pages off the disk. This checks
1122 * for errors and if we're not able to read the page it'll
1123 * trigger parity reconstruction. The rmw will be finished
1124 * after we've reconstructed the failed stripes
1125 */
1126static void validate_rbio_for_rmw(struct btrfs_raid_bio *rbio)
1127{
1128 if (rbio->faila >= 0 || rbio->failb >= 0) {
1129 BUG_ON(rbio->faila == rbio->real_stripes - 1);
1130 __raid56_parity_recover(rbio);
1131 } else {
1132 finish_rmw(rbio);
1133 }
1134}
1135
1136/*
1137 * helper function to walk our bio list and populate the bio_pages array with
1138 * the result. This seems expensive, but it is faster than constantly
1139 * searching through the bio list as we setup the IO in finish_rmw or stripe
1140 * reconstruction.
1141 *
1142 * This must be called before you trust the answers from page_in_rbio
1143 */
1144static void index_rbio_pages(struct btrfs_raid_bio *rbio)
1145{
1146 struct bio *bio;
1147 u64 start;
1148 unsigned long stripe_offset;
1149 unsigned long page_index;
1150
1151 spin_lock_irq(&rbio->bio_list_lock);
1152 bio_list_for_each(bio, &rbio->bio_list) {
1153 struct bio_vec bvec;
1154 struct bvec_iter iter;
1155 int i = 0;
1156
1157 start = bio->bi_iter.bi_sector << 9;
1158 stripe_offset = start - rbio->bbio->raid_map[0];
1159 page_index = stripe_offset >> PAGE_SHIFT;
1160
1161 if (bio_flagged(bio, BIO_CLONED))
1162 bio->bi_iter = btrfs_io_bio(bio)->iter;
1163
1164 bio_for_each_segment(bvec, bio, iter) {
1165 rbio->bio_pages[page_index + i] = bvec.bv_page;
1166 i++;
1167 }
1168 }
1169 spin_unlock_irq(&rbio->bio_list_lock);
1170}
1171
1172/*
1173 * this is called from one of two situations. We either
1174 * have a full stripe from the higher layers, or we've read all
1175 * the missing bits off disk.
1176 *
1177 * This will calculate the parity and then send down any
1178 * changed blocks.
1179 */
1180static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
1181{
1182 struct btrfs_bio *bbio = rbio->bbio;
1183 void **pointers = rbio->finish_pointers;
1184 int nr_data = rbio->nr_data;
1185 int stripe;
1186 int pagenr;
1187 bool has_qstripe;
1188 struct bio_list bio_list;
1189 struct bio *bio;
1190 int ret;
1191
1192 bio_list_init(&bio_list);
1193
1194 if (rbio->real_stripes - rbio->nr_data == 1)
1195 has_qstripe = false;
1196 else if (rbio->real_stripes - rbio->nr_data == 2)
1197 has_qstripe = true;
1198 else
1199 BUG();
1200
1201 /* at this point we either have a full stripe,
1202 * or we've read the full stripe from the drive.
1203 * recalculate the parity and write the new results.
1204 *
1205 * We're not allowed to add any new bios to the
1206 * bio list here, anyone else that wants to
1207 * change this stripe needs to do their own rmw.
1208 */
1209 spin_lock_irq(&rbio->bio_list_lock);
1210 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1211 spin_unlock_irq(&rbio->bio_list_lock);
1212
1213 atomic_set(&rbio->error, 0);
1214
1215 /*
1216 * now that we've set rmw_locked, run through the
1217 * bio list one last time and map the page pointers
1218 *
1219 * We don't cache full rbios because we're assuming
1220 * the higher layers are unlikely to use this area of
1221 * the disk again soon. If they do use it again,
1222 * hopefully they will send another full bio.
1223 */
1224 index_rbio_pages(rbio);
1225 if (!rbio_is_full(rbio))
1226 cache_rbio_pages(rbio);
1227 else
1228 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
1229
1230 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1231 struct page *p;
1232 /* first collect one page from each data stripe */
1233 for (stripe = 0; stripe < nr_data; stripe++) {
1234 p = page_in_rbio(rbio, stripe, pagenr, 0);
1235 pointers[stripe] = kmap_local_page(p);
1236 }
1237
1238 /* then add the parity stripe */
1239 p = rbio_pstripe_page(rbio, pagenr);
1240 SetPageUptodate(p);
1241 pointers[stripe++] = kmap_local_page(p);
1242
1243 if (has_qstripe) {
1244
1245 /*
1246 * raid6, add the qstripe and call the
1247 * library function to fill in our p/q
1248 */
1249 p = rbio_qstripe_page(rbio, pagenr);
1250 SetPageUptodate(p);
1251 pointers[stripe++] = kmap_local_page(p);
1252
1253 raid6_call.gen_syndrome(rbio->real_stripes, PAGE_SIZE,
1254 pointers);
1255 } else {
1256 /* raid5 */
1257 copy_page(pointers[nr_data], pointers[0]);
1258 run_xor(pointers + 1, nr_data - 1, PAGE_SIZE);
1259 }
1260 for (stripe = stripe - 1; stripe >= 0; stripe--)
1261 kunmap_local(pointers[stripe]);
1262 }
1263
1264 /*
1265 * time to start writing. Make bios for everything from the
1266 * higher layers (the bio_list in our rbio) and our p/q. Ignore
1267 * everything else.
1268 */
1269 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1270 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1271 struct page *page;
1272 if (stripe < rbio->nr_data) {
1273 page = page_in_rbio(rbio, stripe, pagenr, 1);
1274 if (!page)
1275 continue;
1276 } else {
1277 page = rbio_stripe_page(rbio, stripe, pagenr);
1278 }
1279
1280 ret = rbio_add_io_page(rbio, &bio_list,
1281 page, stripe, pagenr, rbio->stripe_len);
1282 if (ret)
1283 goto cleanup;
1284 }
1285 }
1286
1287 if (likely(!bbio->num_tgtdevs))
1288 goto write_data;
1289
1290 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1291 if (!bbio->tgtdev_map[stripe])
1292 continue;
1293
1294 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1295 struct page *page;
1296 if (stripe < rbio->nr_data) {
1297 page = page_in_rbio(rbio, stripe, pagenr, 1);
1298 if (!page)
1299 continue;
1300 } else {
1301 page = rbio_stripe_page(rbio, stripe, pagenr);
1302 }
1303
1304 ret = rbio_add_io_page(rbio, &bio_list, page,
1305 rbio->bbio->tgtdev_map[stripe],
1306 pagenr, rbio->stripe_len);
1307 if (ret)
1308 goto cleanup;
1309 }
1310 }
1311
1312write_data:
1313 atomic_set(&rbio->stripes_pending, bio_list_size(&bio_list));
1314 BUG_ON(atomic_read(&rbio->stripes_pending) == 0);
1315
1316 while ((bio = bio_list_pop(&bio_list))) {
1317 bio->bi_private = rbio;
1318 bio->bi_end_io = raid_write_end_io;
1319 bio->bi_opf = REQ_OP_WRITE;
1320
1321 submit_bio(bio);
1322 }
1323 return;
1324
1325cleanup:
1326 rbio_orig_end_io(rbio, BLK_STS_IOERR);
1327
1328 while ((bio = bio_list_pop(&bio_list)))
1329 bio_put(bio);
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 int i;
1342 struct btrfs_bio_stripe *stripe;
1343
1344 physical <<= 9;
1345
1346 for (i = 0; i < rbio->bbio->num_stripes; i++) {
1347 stripe = &rbio->bbio->stripes[i];
1348 if (in_range(physical, stripe->physical, rbio->stripe_len) &&
1349 stripe->dev->bdev && bio->bi_bdev == stripe->dev->bdev) {
1350 return i;
1351 }
1352 }
1353 return -1;
1354}
1355
1356/*
1357 * helper to find the stripe number for a given
1358 * bio (before mapping). Used to figure out which stripe has
1359 * failed. This looks up based on logical block numbers.
1360 */
1361static int find_logical_bio_stripe(struct btrfs_raid_bio *rbio,
1362 struct bio *bio)
1363{
1364 u64 logical = bio->bi_iter.bi_sector << 9;
1365 int i;
1366
1367 for (i = 0; i < rbio->nr_data; i++) {
1368 u64 stripe_start = rbio->bbio->raid_map[i];
1369
1370 if (in_range(logical, stripe_start, rbio->stripe_len))
1371 return i;
1372 }
1373 return -1;
1374}
1375
1376/*
1377 * returns -EIO if we had too many failures
1378 */
1379static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed)
1380{
1381 unsigned long flags;
1382 int ret = 0;
1383
1384 spin_lock_irqsave(&rbio->bio_list_lock, flags);
1385
1386 /* we already know this stripe is bad, move on */
1387 if (rbio->faila == failed || rbio->failb == failed)
1388 goto out;
1389
1390 if (rbio->faila == -1) {
1391 /* first failure on this rbio */
1392 rbio->faila = failed;
1393 atomic_inc(&rbio->error);
1394 } else if (rbio->failb == -1) {
1395 /* second failure on this rbio */
1396 rbio->failb = failed;
1397 atomic_inc(&rbio->error);
1398 } else {
1399 ret = -EIO;
1400 }
1401out:
1402 spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
1403
1404 return ret;
1405}
1406
1407/*
1408 * helper to fail a stripe based on a physical disk
1409 * bio.
1410 */
1411static int fail_bio_stripe(struct btrfs_raid_bio *rbio,
1412 struct bio *bio)
1413{
1414 int failed = find_bio_stripe(rbio, bio);
1415
1416 if (failed < 0)
1417 return -EIO;
1418
1419 return fail_rbio_index(rbio, failed);
1420}
1421
1422/*
1423 * this sets each page in the bio uptodate. It should only be used on private
1424 * rbio pages, nothing that comes in from the higher layers
1425 */
1426static void set_bio_pages_uptodate(struct bio *bio)
1427{
1428 struct bio_vec *bvec;
1429 struct bvec_iter_all iter_all;
1430
1431 ASSERT(!bio_flagged(bio, BIO_CLONED));
1432
1433 bio_for_each_segment_all(bvec, bio, iter_all)
1434 SetPageUptodate(bvec->bv_page);
1435}
1436
1437/*
1438 * end io for the read phase of the rmw cycle. All the bios here are physical
1439 * stripe bios we've read from the disk so we can recalculate the parity of the
1440 * stripe.
1441 *
1442 * This will usually kick off finish_rmw once all the bios are read in, but it
1443 * may trigger parity reconstruction if we had any errors along the way
1444 */
1445static void raid_rmw_end_io(struct bio *bio)
1446{
1447 struct btrfs_raid_bio *rbio = bio->bi_private;
1448
1449 if (bio->bi_status)
1450 fail_bio_stripe(rbio, bio);
1451 else
1452 set_bio_pages_uptodate(bio);
1453
1454 bio_put(bio);
1455
1456 if (!atomic_dec_and_test(&rbio->stripes_pending))
1457 return;
1458
1459 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
1460 goto cleanup;
1461
1462 /*
1463 * this will normally call finish_rmw to start our write
1464 * but if there are any failed stripes we'll reconstruct
1465 * from parity first
1466 */
1467 validate_rbio_for_rmw(rbio);
1468 return;
1469
1470cleanup:
1471
1472 rbio_orig_end_io(rbio, BLK_STS_IOERR);
1473}
1474
1475/*
1476 * the stripe must be locked by the caller. It will
1477 * unlock after all the writes are done
1478 */
1479static int raid56_rmw_stripe(struct btrfs_raid_bio *rbio)
1480{
1481 int bios_to_read = 0;
1482 struct bio_list bio_list;
1483 int ret;
1484 int pagenr;
1485 int stripe;
1486 struct bio *bio;
1487
1488 bio_list_init(&bio_list);
1489
1490 ret = alloc_rbio_pages(rbio);
1491 if (ret)
1492 goto cleanup;
1493
1494 index_rbio_pages(rbio);
1495
1496 atomic_set(&rbio->error, 0);
1497 /*
1498 * build a list of bios to read all the missing parts of this
1499 * stripe
1500 */
1501 for (stripe = 0; stripe < rbio->nr_data; stripe++) {
1502 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1503 struct page *page;
1504 /*
1505 * we want to find all the pages missing from
1506 * the rbio and read them from the disk. If
1507 * page_in_rbio finds a page in the bio list
1508 * we don't need to read it off the stripe.
1509 */
1510 page = page_in_rbio(rbio, stripe, pagenr, 1);
1511 if (page)
1512 continue;
1513
1514 page = rbio_stripe_page(rbio, stripe, pagenr);
1515 /*
1516 * the bio cache may have handed us an uptodate
1517 * page. If so, be happy and use it
1518 */
1519 if (PageUptodate(page))
1520 continue;
1521
1522 ret = rbio_add_io_page(rbio, &bio_list, page,
1523 stripe, pagenr, rbio->stripe_len);
1524 if (ret)
1525 goto cleanup;
1526 }
1527 }
1528
1529 bios_to_read = bio_list_size(&bio_list);
1530 if (!bios_to_read) {
1531 /*
1532 * this can happen if others have merged with
1533 * us, it means there is nothing left to read.
1534 * But if there are missing devices it may not be
1535 * safe to do the full stripe write yet.
1536 */
1537 goto finish;
1538 }
1539
1540 /*
1541 * the bbio may be freed once we submit the last bio. Make sure
1542 * not to touch it after that
1543 */
1544 atomic_set(&rbio->stripes_pending, bios_to_read);
1545 while ((bio = bio_list_pop(&bio_list))) {
1546 bio->bi_private = rbio;
1547 bio->bi_end_io = raid_rmw_end_io;
1548 bio->bi_opf = REQ_OP_READ;
1549
1550 btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
1551
1552 submit_bio(bio);
1553 }
1554 /* the actual write will happen once the reads are done */
1555 return 0;
1556
1557cleanup:
1558 rbio_orig_end_io(rbio, BLK_STS_IOERR);
1559
1560 while ((bio = bio_list_pop(&bio_list)))
1561 bio_put(bio);
1562
1563 return -EIO;
1564
1565finish:
1566 validate_rbio_for_rmw(rbio);
1567 return 0;
1568}
1569
1570/*
1571 * if the upper layers pass in a full stripe, we thank them by only allocating
1572 * enough pages to hold the parity, and sending it all down quickly.
1573 */
1574static int full_stripe_write(struct btrfs_raid_bio *rbio)
1575{
1576 int ret;
1577
1578 ret = alloc_rbio_parity_pages(rbio);
1579 if (ret) {
1580 __free_raid_bio(rbio);
1581 return ret;
1582 }
1583
1584 ret = lock_stripe_add(rbio);
1585 if (ret == 0)
1586 finish_rmw(rbio);
1587 return 0;
1588}
1589
1590/*
1591 * partial stripe writes get handed over to async helpers.
1592 * We're really hoping to merge a few more writes into this
1593 * rbio before calculating new parity
1594 */
1595static int partial_stripe_write(struct btrfs_raid_bio *rbio)
1596{
1597 int ret;
1598
1599 ret = lock_stripe_add(rbio);
1600 if (ret == 0)
1601 start_async_work(rbio, rmw_work);
1602 return 0;
1603}
1604
1605/*
1606 * sometimes while we were reading from the drive to
1607 * recalculate parity, enough new bios come into create
1608 * a full stripe. So we do a check here to see if we can
1609 * go directly to finish_rmw
1610 */
1611static int __raid56_parity_write(struct btrfs_raid_bio *rbio)
1612{
1613 /* head off into rmw land if we don't have a full stripe */
1614 if (!rbio_is_full(rbio))
1615 return partial_stripe_write(rbio);
1616 return full_stripe_write(rbio);
1617}
1618
1619/*
1620 * We use plugging call backs to collect full stripes.
1621 * Any time we get a partial stripe write while plugged
1622 * we collect it into a list. When the unplug comes down,
1623 * we sort the list by logical block number and merge
1624 * everything we can into the same rbios
1625 */
1626struct btrfs_plug_cb {
1627 struct blk_plug_cb cb;
1628 struct btrfs_fs_info *info;
1629 struct list_head rbio_list;
1630 struct btrfs_work work;
1631};
1632
1633/*
1634 * rbios on the plug list are sorted for easier merging.
1635 */
1636static int plug_cmp(void *priv, const struct list_head *a,
1637 const struct list_head *b)
1638{
1639 struct btrfs_raid_bio *ra = container_of(a, struct btrfs_raid_bio,
1640 plug_list);
1641 struct btrfs_raid_bio *rb = container_of(b, struct btrfs_raid_bio,
1642 plug_list);
1643 u64 a_sector = ra->bio_list.head->bi_iter.bi_sector;
1644 u64 b_sector = rb->bio_list.head->bi_iter.bi_sector;
1645
1646 if (a_sector < b_sector)
1647 return -1;
1648 if (a_sector > b_sector)
1649 return 1;
1650 return 0;
1651}
1652
1653static void run_plug(struct btrfs_plug_cb *plug)
1654{
1655 struct btrfs_raid_bio *cur;
1656 struct btrfs_raid_bio *last = NULL;
1657
1658 /*
1659 * sort our plug list then try to merge
1660 * everything we can in hopes of creating full
1661 * stripes.
1662 */
1663 list_sort(NULL, &plug->rbio_list, plug_cmp);
1664 while (!list_empty(&plug->rbio_list)) {
1665 cur = list_entry(plug->rbio_list.next,
1666 struct btrfs_raid_bio, plug_list);
1667 list_del_init(&cur->plug_list);
1668
1669 if (rbio_is_full(cur)) {
1670 int ret;
1671
1672 /* we have a full stripe, send it down */
1673 ret = full_stripe_write(cur);
1674 BUG_ON(ret);
1675 continue;
1676 }
1677 if (last) {
1678 if (rbio_can_merge(last, cur)) {
1679 merge_rbio(last, cur);
1680 __free_raid_bio(cur);
1681 continue;
1682
1683 }
1684 __raid56_parity_write(last);
1685 }
1686 last = cur;
1687 }
1688 if (last) {
1689 __raid56_parity_write(last);
1690 }
1691 kfree(plug);
1692}
1693
1694/*
1695 * if the unplug comes from schedule, we have to push the
1696 * work off to a helper thread
1697 */
1698static void unplug_work(struct btrfs_work *work)
1699{
1700 struct btrfs_plug_cb *plug;
1701 plug = container_of(work, struct btrfs_plug_cb, work);
1702 run_plug(plug);
1703}
1704
1705static void btrfs_raid_unplug(struct blk_plug_cb *cb, bool from_schedule)
1706{
1707 struct btrfs_plug_cb *plug;
1708 plug = container_of(cb, struct btrfs_plug_cb, cb);
1709
1710 if (from_schedule) {
1711 btrfs_init_work(&plug->work, unplug_work, NULL, NULL);
1712 btrfs_queue_work(plug->info->rmw_workers,
1713 &plug->work);
1714 return;
1715 }
1716 run_plug(plug);
1717}
1718
1719/*
1720 * our main entry point for writes from the rest of the FS.
1721 */
1722int raid56_parity_write(struct btrfs_fs_info *fs_info, struct bio *bio,
1723 struct btrfs_bio *bbio, u64 stripe_len)
1724{
1725 struct btrfs_raid_bio *rbio;
1726 struct btrfs_plug_cb *plug = NULL;
1727 struct blk_plug_cb *cb;
1728 int ret;
1729
1730 rbio = alloc_rbio(fs_info, bbio, stripe_len);
1731 if (IS_ERR(rbio)) {
1732 btrfs_put_bbio(bbio);
1733 return PTR_ERR(rbio);
1734 }
1735 bio_list_add(&rbio->bio_list, bio);
1736 rbio->bio_list_bytes = bio->bi_iter.bi_size;
1737 rbio->operation = BTRFS_RBIO_WRITE;
1738
1739 btrfs_bio_counter_inc_noblocked(fs_info);
1740 rbio->generic_bio_cnt = 1;
1741
1742 /*
1743 * don't plug on full rbios, just get them out the door
1744 * as quickly as we can
1745 */
1746 if (rbio_is_full(rbio)) {
1747 ret = full_stripe_write(rbio);
1748 if (ret)
1749 btrfs_bio_counter_dec(fs_info);
1750 return ret;
1751 }
1752
1753 cb = blk_check_plugged(btrfs_raid_unplug, fs_info, sizeof(*plug));
1754 if (cb) {
1755 plug = container_of(cb, struct btrfs_plug_cb, cb);
1756 if (!plug->info) {
1757 plug->info = fs_info;
1758 INIT_LIST_HEAD(&plug->rbio_list);
1759 }
1760 list_add_tail(&rbio->plug_list, &plug->rbio_list);
1761 ret = 0;
1762 } else {
1763 ret = __raid56_parity_write(rbio);
1764 if (ret)
1765 btrfs_bio_counter_dec(fs_info);
1766 }
1767 return ret;
1768}
1769
1770/*
1771 * all parity reconstruction happens here. We've read in everything
1772 * we can find from the drives and this does the heavy lifting of
1773 * sorting the good from the bad.
1774 */
1775static void __raid_recover_end_io(struct btrfs_raid_bio *rbio)
1776{
1777 int pagenr, stripe;
1778 void **pointers;
1779 void **unmap_array;
1780 int faila = -1, failb = -1;
1781 struct page *page;
1782 blk_status_t err;
1783 int i;
1784
1785 pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
1786 if (!pointers) {
1787 err = BLK_STS_RESOURCE;
1788 goto cleanup_io;
1789 }
1790
1791 /*
1792 * Store copy of pointers that does not get reordered during
1793 * reconstruction so that kunmap_local works.
1794 */
1795 unmap_array = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
1796 if (!unmap_array) {
1797 err = BLK_STS_RESOURCE;
1798 goto cleanup_pointers;
1799 }
1800
1801 faila = rbio->faila;
1802 failb = rbio->failb;
1803
1804 if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1805 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) {
1806 spin_lock_irq(&rbio->bio_list_lock);
1807 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1808 spin_unlock_irq(&rbio->bio_list_lock);
1809 }
1810
1811 index_rbio_pages(rbio);
1812
1813 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1814 /*
1815 * Now we just use bitmap to mark the horizontal stripes in
1816 * which we have data when doing parity scrub.
1817 */
1818 if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB &&
1819 !test_bit(pagenr, rbio->dbitmap))
1820 continue;
1821
1822 /*
1823 * Setup our array of pointers with pages from each stripe
1824 *
1825 * NOTE: store a duplicate array of pointers to preserve the
1826 * pointer order
1827 */
1828 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1829 /*
1830 * if we're rebuilding a read, we have to use
1831 * pages from the bio list
1832 */
1833 if ((rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1834 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) &&
1835 (stripe == faila || stripe == failb)) {
1836 page = page_in_rbio(rbio, stripe, pagenr, 0);
1837 } else {
1838 page = rbio_stripe_page(rbio, stripe, pagenr);
1839 }
1840 pointers[stripe] = kmap_local_page(page);
1841 unmap_array[stripe] = pointers[stripe];
1842 }
1843
1844 /* all raid6 handling here */
1845 if (rbio->bbio->map_type & BTRFS_BLOCK_GROUP_RAID6) {
1846 /*
1847 * single failure, rebuild from parity raid5
1848 * style
1849 */
1850 if (failb < 0) {
1851 if (faila == rbio->nr_data) {
1852 /*
1853 * Just the P stripe has failed, without
1854 * a bad data or Q stripe.
1855 * TODO, we should redo the xor here.
1856 */
1857 err = BLK_STS_IOERR;
1858 goto cleanup;
1859 }
1860 /*
1861 * a single failure in raid6 is rebuilt
1862 * in the pstripe code below
1863 */
1864 goto pstripe;
1865 }
1866
1867 /* make sure our ps and qs are in order */
1868 if (faila > failb)
1869 swap(faila, failb);
1870
1871 /* if the q stripe is failed, do a pstripe reconstruction
1872 * from the xors.
1873 * If both the q stripe and the P stripe are failed, we're
1874 * here due to a crc mismatch and we can't give them the
1875 * data they want
1876 */
1877 if (rbio->bbio->raid_map[failb] == RAID6_Q_STRIPE) {
1878 if (rbio->bbio->raid_map[faila] ==
1879 RAID5_P_STRIPE) {
1880 err = BLK_STS_IOERR;
1881 goto cleanup;
1882 }
1883 /*
1884 * otherwise we have one bad data stripe and
1885 * a good P stripe. raid5!
1886 */
1887 goto pstripe;
1888 }
1889
1890 if (rbio->bbio->raid_map[failb] == RAID5_P_STRIPE) {
1891 raid6_datap_recov(rbio->real_stripes,
1892 PAGE_SIZE, faila, pointers);
1893 } else {
1894 raid6_2data_recov(rbio->real_stripes,
1895 PAGE_SIZE, faila, failb,
1896 pointers);
1897 }
1898 } else {
1899 void *p;
1900
1901 /* rebuild from P stripe here (raid5 or raid6) */
1902 BUG_ON(failb != -1);
1903pstripe:
1904 /* Copy parity block into failed block to start with */
1905 copy_page(pointers[faila], pointers[rbio->nr_data]);
1906
1907 /* rearrange the pointer array */
1908 p = pointers[faila];
1909 for (stripe = faila; stripe < rbio->nr_data - 1; stripe++)
1910 pointers[stripe] = pointers[stripe + 1];
1911 pointers[rbio->nr_data - 1] = p;
1912
1913 /* xor in the rest */
1914 run_xor(pointers, rbio->nr_data - 1, PAGE_SIZE);
1915 }
1916 /* if we're doing this rebuild as part of an rmw, go through
1917 * and set all of our private rbio pages in the
1918 * failed stripes as uptodate. This way finish_rmw will
1919 * know they can be trusted. If this was a read reconstruction,
1920 * other endio functions will fiddle the uptodate bits
1921 */
1922 if (rbio->operation == BTRFS_RBIO_WRITE) {
1923 for (i = 0; i < rbio->stripe_npages; i++) {
1924 if (faila != -1) {
1925 page = rbio_stripe_page(rbio, faila, i);
1926 SetPageUptodate(page);
1927 }
1928 if (failb != -1) {
1929 page = rbio_stripe_page(rbio, failb, i);
1930 SetPageUptodate(page);
1931 }
1932 }
1933 }
1934 for (stripe = rbio->real_stripes - 1; stripe >= 0; stripe--)
1935 kunmap_local(unmap_array[stripe]);
1936 }
1937
1938 err = BLK_STS_OK;
1939cleanup:
1940 kfree(unmap_array);
1941cleanup_pointers:
1942 kfree(pointers);
1943
1944cleanup_io:
1945 /*
1946 * Similar to READ_REBUILD, REBUILD_MISSING at this point also has a
1947 * valid rbio which is consistent with ondisk content, thus such a
1948 * valid rbio can be cached to avoid further disk reads.
1949 */
1950 if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1951 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) {
1952 /*
1953 * - In case of two failures, where rbio->failb != -1:
1954 *
1955 * Do not cache this rbio since the above read reconstruction
1956 * (raid6_datap_recov() or raid6_2data_recov()) may have
1957 * changed some content of stripes which are not identical to
1958 * on-disk content any more, otherwise, a later write/recover
1959 * may steal stripe_pages from this rbio and end up with
1960 * corruptions or rebuild failures.
1961 *
1962 * - In case of single failure, where rbio->failb == -1:
1963 *
1964 * Cache this rbio iff the above read reconstruction is
1965 * executed without problems.
1966 */
1967 if (err == BLK_STS_OK && rbio->failb < 0)
1968 cache_rbio_pages(rbio);
1969 else
1970 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
1971
1972 rbio_orig_end_io(rbio, err);
1973 } else if (err == BLK_STS_OK) {
1974 rbio->faila = -1;
1975 rbio->failb = -1;
1976
1977 if (rbio->operation == BTRFS_RBIO_WRITE)
1978 finish_rmw(rbio);
1979 else if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB)
1980 finish_parity_scrub(rbio, 0);
1981 else
1982 BUG();
1983 } else {
1984 rbio_orig_end_io(rbio, err);
1985 }
1986}
1987
1988/*
1989 * This is called only for stripes we've read from disk to
1990 * reconstruct the parity.
1991 */
1992static void raid_recover_end_io(struct bio *bio)
1993{
1994 struct btrfs_raid_bio *rbio = bio->bi_private;
1995
1996 /*
1997 * we only read stripe pages off the disk, set them
1998 * up to date if there were no errors
1999 */
2000 if (bio->bi_status)
2001 fail_bio_stripe(rbio, bio);
2002 else
2003 set_bio_pages_uptodate(bio);
2004 bio_put(bio);
2005
2006 if (!atomic_dec_and_test(&rbio->stripes_pending))
2007 return;
2008
2009 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
2010 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2011 else
2012 __raid_recover_end_io(rbio);
2013}
2014
2015/*
2016 * reads everything we need off the disk to reconstruct
2017 * the parity. endio handlers trigger final reconstruction
2018 * when the IO is done.
2019 *
2020 * This is used both for reads from the higher layers and for
2021 * parity construction required to finish a rmw cycle.
2022 */
2023static int __raid56_parity_recover(struct btrfs_raid_bio *rbio)
2024{
2025 int bios_to_read = 0;
2026 struct bio_list bio_list;
2027 int ret;
2028 int pagenr;
2029 int stripe;
2030 struct bio *bio;
2031
2032 bio_list_init(&bio_list);
2033
2034 ret = alloc_rbio_pages(rbio);
2035 if (ret)
2036 goto cleanup;
2037
2038 atomic_set(&rbio->error, 0);
2039
2040 /*
2041 * read everything that hasn't failed. Thanks to the
2042 * stripe cache, it is possible that some or all of these
2043 * pages are going to be uptodate.
2044 */
2045 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
2046 if (rbio->faila == stripe || rbio->failb == stripe) {
2047 atomic_inc(&rbio->error);
2048 continue;
2049 }
2050
2051 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
2052 struct page *p;
2053
2054 /*
2055 * the rmw code may have already read this
2056 * page in
2057 */
2058 p = rbio_stripe_page(rbio, stripe, pagenr);
2059 if (PageUptodate(p))
2060 continue;
2061
2062 ret = rbio_add_io_page(rbio, &bio_list,
2063 rbio_stripe_page(rbio, stripe, pagenr),
2064 stripe, pagenr, rbio->stripe_len);
2065 if (ret < 0)
2066 goto cleanup;
2067 }
2068 }
2069
2070 bios_to_read = bio_list_size(&bio_list);
2071 if (!bios_to_read) {
2072 /*
2073 * we might have no bios to read just because the pages
2074 * were up to date, or we might have no bios to read because
2075 * the devices were gone.
2076 */
2077 if (atomic_read(&rbio->error) <= rbio->bbio->max_errors) {
2078 __raid_recover_end_io(rbio);
2079 return 0;
2080 } else {
2081 goto cleanup;
2082 }
2083 }
2084
2085 /*
2086 * the bbio may be freed once we submit the last bio. Make sure
2087 * not to touch it after that
2088 */
2089 atomic_set(&rbio->stripes_pending, bios_to_read);
2090 while ((bio = bio_list_pop(&bio_list))) {
2091 bio->bi_private = rbio;
2092 bio->bi_end_io = raid_recover_end_io;
2093 bio->bi_opf = REQ_OP_READ;
2094
2095 btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
2096
2097 submit_bio(bio);
2098 }
2099
2100 return 0;
2101
2102cleanup:
2103 if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
2104 rbio->operation == BTRFS_RBIO_REBUILD_MISSING)
2105 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2106
2107 while ((bio = bio_list_pop(&bio_list)))
2108 bio_put(bio);
2109
2110 return -EIO;
2111}
2112
2113/*
2114 * the main entry point for reads from the higher layers. This
2115 * is really only called when the normal read path had a failure,
2116 * so we assume the bio they send down corresponds to a failed part
2117 * of the drive.
2118 */
2119int raid56_parity_recover(struct btrfs_fs_info *fs_info, struct bio *bio,
2120 struct btrfs_bio *bbio, u64 stripe_len,
2121 int mirror_num, int generic_io)
2122{
2123 struct btrfs_raid_bio *rbio;
2124 int ret;
2125
2126 if (generic_io) {
2127 ASSERT(bbio->mirror_num == mirror_num);
2128 btrfs_io_bio(bio)->mirror_num = mirror_num;
2129 }
2130
2131 rbio = alloc_rbio(fs_info, bbio, stripe_len);
2132 if (IS_ERR(rbio)) {
2133 if (generic_io)
2134 btrfs_put_bbio(bbio);
2135 return PTR_ERR(rbio);
2136 }
2137
2138 rbio->operation = BTRFS_RBIO_READ_REBUILD;
2139 bio_list_add(&rbio->bio_list, bio);
2140 rbio->bio_list_bytes = bio->bi_iter.bi_size;
2141
2142 rbio->faila = find_logical_bio_stripe(rbio, bio);
2143 if (rbio->faila == -1) {
2144 btrfs_warn(fs_info,
2145 "%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)",
2146 __func__, bio->bi_iter.bi_sector << 9,
2147 (u64)bio->bi_iter.bi_size, bbio->map_type);
2148 if (generic_io)
2149 btrfs_put_bbio(bbio);
2150 kfree(rbio);
2151 return -EIO;
2152 }
2153
2154 if (generic_io) {
2155 btrfs_bio_counter_inc_noblocked(fs_info);
2156 rbio->generic_bio_cnt = 1;
2157 } else {
2158 btrfs_get_bbio(bbio);
2159 }
2160
2161 /*
2162 * Loop retry:
2163 * for 'mirror == 2', reconstruct from all other stripes.
2164 * for 'mirror_num > 2', select a stripe to fail on every retry.
2165 */
2166 if (mirror_num > 2) {
2167 /*
2168 * 'mirror == 3' is to fail the p stripe and
2169 * reconstruct from the q stripe. 'mirror > 3' is to
2170 * fail a data stripe and reconstruct from p+q stripe.
2171 */
2172 rbio->failb = rbio->real_stripes - (mirror_num - 1);
2173 ASSERT(rbio->failb > 0);
2174 if (rbio->failb <= rbio->faila)
2175 rbio->failb--;
2176 }
2177
2178 ret = lock_stripe_add(rbio);
2179
2180 /*
2181 * __raid56_parity_recover will end the bio with
2182 * any errors it hits. We don't want to return
2183 * its error value up the stack because our caller
2184 * will end up calling bio_endio with any nonzero
2185 * return
2186 */
2187 if (ret == 0)
2188 __raid56_parity_recover(rbio);
2189 /*
2190 * our rbio has been added to the list of
2191 * rbios that will be handled after the
2192 * currently lock owner is done
2193 */
2194 return 0;
2195
2196}
2197
2198static void rmw_work(struct btrfs_work *work)
2199{
2200 struct btrfs_raid_bio *rbio;
2201
2202 rbio = container_of(work, struct btrfs_raid_bio, work);
2203 raid56_rmw_stripe(rbio);
2204}
2205
2206static void read_rebuild_work(struct btrfs_work *work)
2207{
2208 struct btrfs_raid_bio *rbio;
2209
2210 rbio = container_of(work, struct btrfs_raid_bio, work);
2211 __raid56_parity_recover(rbio);
2212}
2213
2214/*
2215 * The following code is used to scrub/replace the parity stripe
2216 *
2217 * Caller must have already increased bio_counter for getting @bbio.
2218 *
2219 * Note: We need make sure all the pages that add into the scrub/replace
2220 * raid bio are correct and not be changed during the scrub/replace. That
2221 * is those pages just hold metadata or file data with checksum.
2222 */
2223
2224struct btrfs_raid_bio *
2225raid56_parity_alloc_scrub_rbio(struct btrfs_fs_info *fs_info, struct bio *bio,
2226 struct btrfs_bio *bbio, u64 stripe_len,
2227 struct btrfs_device *scrub_dev,
2228 unsigned long *dbitmap, int stripe_nsectors)
2229{
2230 struct btrfs_raid_bio *rbio;
2231 int i;
2232
2233 rbio = alloc_rbio(fs_info, bbio, stripe_len);
2234 if (IS_ERR(rbio))
2235 return NULL;
2236 bio_list_add(&rbio->bio_list, bio);
2237 /*
2238 * This is a special bio which is used to hold the completion handler
2239 * and make the scrub rbio is similar to the other types
2240 */
2241 ASSERT(!bio->bi_iter.bi_size);
2242 rbio->operation = BTRFS_RBIO_PARITY_SCRUB;
2243
2244 /*
2245 * After mapping bbio with BTRFS_MAP_WRITE, parities have been sorted
2246 * to the end position, so this search can start from the first parity
2247 * stripe.
2248 */
2249 for (i = rbio->nr_data; i < rbio->real_stripes; i++) {
2250 if (bbio->stripes[i].dev == scrub_dev) {
2251 rbio->scrubp = i;
2252 break;
2253 }
2254 }
2255 ASSERT(i < rbio->real_stripes);
2256
2257 /* Now we just support the sectorsize equals to page size */
2258 ASSERT(fs_info->sectorsize == PAGE_SIZE);
2259 ASSERT(rbio->stripe_npages == stripe_nsectors);
2260 bitmap_copy(rbio->dbitmap, dbitmap, stripe_nsectors);
2261
2262 /*
2263 * We have already increased bio_counter when getting bbio, record it
2264 * so we can free it at rbio_orig_end_io().
2265 */
2266 rbio->generic_bio_cnt = 1;
2267
2268 return rbio;
2269}
2270
2271/* Used for both parity scrub and missing. */
2272void raid56_add_scrub_pages(struct btrfs_raid_bio *rbio, struct page *page,
2273 u64 logical)
2274{
2275 int stripe_offset;
2276 int index;
2277
2278 ASSERT(logical >= rbio->bbio->raid_map[0]);
2279 ASSERT(logical + PAGE_SIZE <= rbio->bbio->raid_map[0] +
2280 rbio->stripe_len * rbio->nr_data);
2281 stripe_offset = (int)(logical - rbio->bbio->raid_map[0]);
2282 index = stripe_offset >> PAGE_SHIFT;
2283 rbio->bio_pages[index] = page;
2284}
2285
2286/*
2287 * We just scrub the parity that we have correct data on the same horizontal,
2288 * so we needn't allocate all pages for all the stripes.
2289 */
2290static int alloc_rbio_essential_pages(struct btrfs_raid_bio *rbio)
2291{
2292 int i;
2293 int bit;
2294 int index;
2295 struct page *page;
2296
2297 for_each_set_bit(bit, rbio->dbitmap, rbio->stripe_npages) {
2298 for (i = 0; i < rbio->real_stripes; i++) {
2299 index = i * rbio->stripe_npages + bit;
2300 if (rbio->stripe_pages[index])
2301 continue;
2302
2303 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2304 if (!page)
2305 return -ENOMEM;
2306 rbio->stripe_pages[index] = page;
2307 }
2308 }
2309 return 0;
2310}
2311
2312static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
2313 int need_check)
2314{
2315 struct btrfs_bio *bbio = rbio->bbio;
2316 void **pointers = rbio->finish_pointers;
2317 unsigned long *pbitmap = rbio->finish_pbitmap;
2318 int nr_data = rbio->nr_data;
2319 int stripe;
2320 int pagenr;
2321 bool has_qstripe;
2322 struct page *p_page = NULL;
2323 struct page *q_page = NULL;
2324 struct bio_list bio_list;
2325 struct bio *bio;
2326 int is_replace = 0;
2327 int ret;
2328
2329 bio_list_init(&bio_list);
2330
2331 if (rbio->real_stripes - rbio->nr_data == 1)
2332 has_qstripe = false;
2333 else if (rbio->real_stripes - rbio->nr_data == 2)
2334 has_qstripe = true;
2335 else
2336 BUG();
2337
2338 if (bbio->num_tgtdevs && bbio->tgtdev_map[rbio->scrubp]) {
2339 is_replace = 1;
2340 bitmap_copy(pbitmap, rbio->dbitmap, rbio->stripe_npages);
2341 }
2342
2343 /*
2344 * Because the higher layers(scrubber) are unlikely to
2345 * use this area of the disk again soon, so don't cache
2346 * it.
2347 */
2348 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
2349
2350 if (!need_check)
2351 goto writeback;
2352
2353 p_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2354 if (!p_page)
2355 goto cleanup;
2356 SetPageUptodate(p_page);
2357
2358 if (has_qstripe) {
2359 /* RAID6, allocate and map temp space for the Q stripe */
2360 q_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2361 if (!q_page) {
2362 __free_page(p_page);
2363 goto cleanup;
2364 }
2365 SetPageUptodate(q_page);
2366 pointers[rbio->real_stripes - 1] = kmap_local_page(q_page);
2367 }
2368
2369 atomic_set(&rbio->error, 0);
2370
2371 /* Map the parity stripe just once */
2372 pointers[nr_data] = kmap_local_page(p_page);
2373
2374 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2375 struct page *p;
2376 void *parity;
2377 /* first collect one page from each data stripe */
2378 for (stripe = 0; stripe < nr_data; stripe++) {
2379 p = page_in_rbio(rbio, stripe, pagenr, 0);
2380 pointers[stripe] = kmap_local_page(p);
2381 }
2382
2383 if (has_qstripe) {
2384 /* RAID6, call the library function to fill in our P/Q */
2385 raid6_call.gen_syndrome(rbio->real_stripes, PAGE_SIZE,
2386 pointers);
2387 } else {
2388 /* raid5 */
2389 copy_page(pointers[nr_data], pointers[0]);
2390 run_xor(pointers + 1, nr_data - 1, PAGE_SIZE);
2391 }
2392
2393 /* Check scrubbing parity and repair it */
2394 p = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2395 parity = kmap_local_page(p);
2396 if (memcmp(parity, pointers[rbio->scrubp], PAGE_SIZE))
2397 copy_page(parity, pointers[rbio->scrubp]);
2398 else
2399 /* Parity is right, needn't writeback */
2400 bitmap_clear(rbio->dbitmap, pagenr, 1);
2401 kunmap_local(parity);
2402
2403 for (stripe = nr_data - 1; stripe >= 0; stripe--)
2404 kunmap_local(pointers[stripe]);
2405 }
2406
2407 kunmap_local(pointers[nr_data]);
2408 __free_page(p_page);
2409 if (q_page) {
2410 kunmap_local(pointers[rbio->real_stripes - 1]);
2411 __free_page(q_page);
2412 }
2413
2414writeback:
2415 /*
2416 * time to start writing. Make bios for everything from the
2417 * higher layers (the bio_list in our rbio) and our p/q. Ignore
2418 * everything else.
2419 */
2420 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2421 struct page *page;
2422
2423 page = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2424 ret = rbio_add_io_page(rbio, &bio_list,
2425 page, rbio->scrubp, pagenr, rbio->stripe_len);
2426 if (ret)
2427 goto cleanup;
2428 }
2429
2430 if (!is_replace)
2431 goto submit_write;
2432
2433 for_each_set_bit(pagenr, pbitmap, rbio->stripe_npages) {
2434 struct page *page;
2435
2436 page = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2437 ret = rbio_add_io_page(rbio, &bio_list, page,
2438 bbio->tgtdev_map[rbio->scrubp],
2439 pagenr, rbio->stripe_len);
2440 if (ret)
2441 goto cleanup;
2442 }
2443
2444submit_write:
2445 nr_data = bio_list_size(&bio_list);
2446 if (!nr_data) {
2447 /* Every parity is right */
2448 rbio_orig_end_io(rbio, BLK_STS_OK);
2449 return;
2450 }
2451
2452 atomic_set(&rbio->stripes_pending, nr_data);
2453
2454 while ((bio = bio_list_pop(&bio_list))) {
2455 bio->bi_private = rbio;
2456 bio->bi_end_io = raid_write_end_io;
2457 bio->bi_opf = REQ_OP_WRITE;
2458
2459 submit_bio(bio);
2460 }
2461 return;
2462
2463cleanup:
2464 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2465
2466 while ((bio = bio_list_pop(&bio_list)))
2467 bio_put(bio);
2468}
2469
2470static inline int is_data_stripe(struct btrfs_raid_bio *rbio, int stripe)
2471{
2472 if (stripe >= 0 && stripe < rbio->nr_data)
2473 return 1;
2474 return 0;
2475}
2476
2477/*
2478 * While we're doing the parity check and repair, we could have errors
2479 * in reading pages off the disk. This checks for errors and if we're
2480 * not able to read the page it'll trigger parity reconstruction. The
2481 * parity scrub will be finished after we've reconstructed the failed
2482 * stripes
2483 */
2484static void validate_rbio_for_parity_scrub(struct btrfs_raid_bio *rbio)
2485{
2486 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
2487 goto cleanup;
2488
2489 if (rbio->faila >= 0 || rbio->failb >= 0) {
2490 int dfail = 0, failp = -1;
2491
2492 if (is_data_stripe(rbio, rbio->faila))
2493 dfail++;
2494 else if (is_parity_stripe(rbio->faila))
2495 failp = rbio->faila;
2496
2497 if (is_data_stripe(rbio, rbio->failb))
2498 dfail++;
2499 else if (is_parity_stripe(rbio->failb))
2500 failp = rbio->failb;
2501
2502 /*
2503 * Because we can not use a scrubbing parity to repair
2504 * the data, so the capability of the repair is declined.
2505 * (In the case of RAID5, we can not repair anything)
2506 */
2507 if (dfail > rbio->bbio->max_errors - 1)
2508 goto cleanup;
2509
2510 /*
2511 * If all data is good, only parity is correctly, just
2512 * repair the parity.
2513 */
2514 if (dfail == 0) {
2515 finish_parity_scrub(rbio, 0);
2516 return;
2517 }
2518
2519 /*
2520 * Here means we got one corrupted data stripe and one
2521 * corrupted parity on RAID6, if the corrupted parity
2522 * is scrubbing parity, luckily, use the other one to repair
2523 * the data, or we can not repair the data stripe.
2524 */
2525 if (failp != rbio->scrubp)
2526 goto cleanup;
2527
2528 __raid_recover_end_io(rbio);
2529 } else {
2530 finish_parity_scrub(rbio, 1);
2531 }
2532 return;
2533
2534cleanup:
2535 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2536}
2537
2538/*
2539 * end io for the read phase of the rmw cycle. All the bios here are physical
2540 * stripe bios we've read from the disk so we can recalculate the parity of the
2541 * stripe.
2542 *
2543 * This will usually kick off finish_rmw once all the bios are read in, but it
2544 * may trigger parity reconstruction if we had any errors along the way
2545 */
2546static void raid56_parity_scrub_end_io(struct bio *bio)
2547{
2548 struct btrfs_raid_bio *rbio = bio->bi_private;
2549
2550 if (bio->bi_status)
2551 fail_bio_stripe(rbio, bio);
2552 else
2553 set_bio_pages_uptodate(bio);
2554
2555 bio_put(bio);
2556
2557 if (!atomic_dec_and_test(&rbio->stripes_pending))
2558 return;
2559
2560 /*
2561 * this will normally call finish_rmw to start our write
2562 * but if there are any failed stripes we'll reconstruct
2563 * from parity first
2564 */
2565 validate_rbio_for_parity_scrub(rbio);
2566}
2567
2568static void raid56_parity_scrub_stripe(struct btrfs_raid_bio *rbio)
2569{
2570 int bios_to_read = 0;
2571 struct bio_list bio_list;
2572 int ret;
2573 int pagenr;
2574 int stripe;
2575 struct bio *bio;
2576
2577 bio_list_init(&bio_list);
2578
2579 ret = alloc_rbio_essential_pages(rbio);
2580 if (ret)
2581 goto cleanup;
2582
2583 atomic_set(&rbio->error, 0);
2584 /*
2585 * build a list of bios to read all the missing parts of this
2586 * stripe
2587 */
2588 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
2589 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2590 struct page *page;
2591 /*
2592 * we want to find all the pages missing from
2593 * the rbio and read them from the disk. If
2594 * page_in_rbio finds a page in the bio list
2595 * we don't need to read it off the stripe.
2596 */
2597 page = page_in_rbio(rbio, stripe, pagenr, 1);
2598 if (page)
2599 continue;
2600
2601 page = rbio_stripe_page(rbio, stripe, pagenr);
2602 /*
2603 * the bio cache may have handed us an uptodate
2604 * page. If so, be happy and use it
2605 */
2606 if (PageUptodate(page))
2607 continue;
2608
2609 ret = rbio_add_io_page(rbio, &bio_list, page,
2610 stripe, pagenr, rbio->stripe_len);
2611 if (ret)
2612 goto cleanup;
2613 }
2614 }
2615
2616 bios_to_read = bio_list_size(&bio_list);
2617 if (!bios_to_read) {
2618 /*
2619 * this can happen if others have merged with
2620 * us, it means there is nothing left to read.
2621 * But if there are missing devices it may not be
2622 * safe to do the full stripe write yet.
2623 */
2624 goto finish;
2625 }
2626
2627 /*
2628 * the bbio may be freed once we submit the last bio. Make sure
2629 * not to touch it after that
2630 */
2631 atomic_set(&rbio->stripes_pending, bios_to_read);
2632 while ((bio = bio_list_pop(&bio_list))) {
2633 bio->bi_private = rbio;
2634 bio->bi_end_io = raid56_parity_scrub_end_io;
2635 bio->bi_opf = REQ_OP_READ;
2636
2637 btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
2638
2639 submit_bio(bio);
2640 }
2641 /* the actual write will happen once the reads are done */
2642 return;
2643
2644cleanup:
2645 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2646
2647 while ((bio = bio_list_pop(&bio_list)))
2648 bio_put(bio);
2649
2650 return;
2651
2652finish:
2653 validate_rbio_for_parity_scrub(rbio);
2654}
2655
2656static void scrub_parity_work(struct btrfs_work *work)
2657{
2658 struct btrfs_raid_bio *rbio;
2659
2660 rbio = container_of(work, struct btrfs_raid_bio, work);
2661 raid56_parity_scrub_stripe(rbio);
2662}
2663
2664void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio)
2665{
2666 if (!lock_stripe_add(rbio))
2667 start_async_work(rbio, scrub_parity_work);
2668}
2669
2670/* The following code is used for dev replace of a missing RAID 5/6 device. */
2671
2672struct btrfs_raid_bio *
2673raid56_alloc_missing_rbio(struct btrfs_fs_info *fs_info, struct bio *bio,
2674 struct btrfs_bio *bbio, u64 length)
2675{
2676 struct btrfs_raid_bio *rbio;
2677
2678 rbio = alloc_rbio(fs_info, bbio, length);
2679 if (IS_ERR(rbio))
2680 return NULL;
2681
2682 rbio->operation = BTRFS_RBIO_REBUILD_MISSING;
2683 bio_list_add(&rbio->bio_list, bio);
2684 /*
2685 * This is a special bio which is used to hold the completion handler
2686 * and make the scrub rbio is similar to the other types
2687 */
2688 ASSERT(!bio->bi_iter.bi_size);
2689
2690 rbio->faila = find_logical_bio_stripe(rbio, bio);
2691 if (rbio->faila == -1) {
2692 BUG();
2693 kfree(rbio);
2694 return NULL;
2695 }
2696
2697 /*
2698 * When we get bbio, we have already increased bio_counter, record it
2699 * so we can free it at rbio_orig_end_io()
2700 */
2701 rbio->generic_bio_cnt = 1;
2702
2703 return rbio;
2704}
2705
2706void raid56_submit_missing_rbio(struct btrfs_raid_bio *rbio)
2707{
2708 if (!lock_stripe_add(rbio))
2709 start_async_work(rbio, read_rebuild_work);
2710}