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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 "ctree.h"
17#include "disk-io.h"
18#include "volumes.h"
19#include "raid56.h"
20#include "async-thread.h"
21
22/* set when additional merges to this rbio are not allowed */
23#define RBIO_RMW_LOCKED_BIT 1
24
25/*
26 * set when this rbio is sitting in the hash, but it is just a cache
27 * of past RMW
28 */
29#define RBIO_CACHE_BIT 2
30
31/*
32 * set when it is safe to trust the stripe_pages for caching
33 */
34#define RBIO_CACHE_READY_BIT 3
35
36#define RBIO_CACHE_SIZE 1024
37
38#define BTRFS_STRIPE_HASH_TABLE_BITS 11
39
40/* Used by the raid56 code to lock stripes for read/modify/write */
41struct btrfs_stripe_hash {
42 struct list_head hash_list;
43 spinlock_t lock;
44};
45
46/* Used by the raid56 code to lock stripes for read/modify/write */
47struct btrfs_stripe_hash_table {
48 struct list_head stripe_cache;
49 spinlock_t cache_lock;
50 int cache_size;
51 struct btrfs_stripe_hash table[];
52};
53
54enum btrfs_rbio_ops {
55 BTRFS_RBIO_WRITE,
56 BTRFS_RBIO_READ_REBUILD,
57 BTRFS_RBIO_PARITY_SCRUB,
58 BTRFS_RBIO_REBUILD_MISSING,
59};
60
61struct btrfs_raid_bio {
62 struct btrfs_fs_info *fs_info;
63 struct btrfs_bio *bbio;
64
65 /* while we're doing rmw on a stripe
66 * we put it into a hash table so we can
67 * lock the stripe and merge more rbios
68 * into it.
69 */
70 struct list_head hash_list;
71
72 /*
73 * LRU list for the stripe cache
74 */
75 struct list_head stripe_cache;
76
77 /*
78 * for scheduling work in the helper threads
79 */
80 struct btrfs_work work;
81
82 /*
83 * bio list and bio_list_lock are used
84 * to add more bios into the stripe
85 * in hopes of avoiding the full rmw
86 */
87 struct bio_list bio_list;
88 spinlock_t bio_list_lock;
89
90 /* also protected by the bio_list_lock, the
91 * plug list is used by the plugging code
92 * to collect partial bios while plugged. The
93 * stripe locking code also uses it to hand off
94 * the stripe lock to the next pending IO
95 */
96 struct list_head plug_list;
97
98 /*
99 * flags that tell us if it is safe to
100 * merge with this bio
101 */
102 unsigned long flags;
103
104 /* size of each individual stripe on disk */
105 int stripe_len;
106
107 /* number of data stripes (no p/q) */
108 int nr_data;
109
110 int real_stripes;
111
112 int stripe_npages;
113 /*
114 * set if we're doing a parity rebuild
115 * for a read from higher up, which is handled
116 * differently from a parity rebuild as part of
117 * rmw
118 */
119 enum btrfs_rbio_ops operation;
120
121 /* first bad stripe */
122 int faila;
123
124 /* second bad stripe (for raid6 use) */
125 int failb;
126
127 int scrubp;
128 /*
129 * number of pages needed to represent the full
130 * stripe
131 */
132 int nr_pages;
133
134 /*
135 * size of all the bios in the bio_list. This
136 * helps us decide if the rbio maps to a full
137 * stripe or not
138 */
139 int bio_list_bytes;
140
141 int generic_bio_cnt;
142
143 refcount_t refs;
144
145 atomic_t stripes_pending;
146
147 atomic_t error;
148 /*
149 * these are two arrays of pointers. We allocate the
150 * rbio big enough to hold them both and setup their
151 * locations when the rbio is allocated
152 */
153
154 /* pointers to pages that we allocated for
155 * reading/writing stripes directly from the disk (including P/Q)
156 */
157 struct page **stripe_pages;
158
159 /*
160 * pointers to the pages in the bio_list. Stored
161 * here for faster lookup
162 */
163 struct page **bio_pages;
164
165 /*
166 * bitmap to record which horizontal stripe has data
167 */
168 unsigned long *dbitmap;
169
170 /* allocated with real_stripes-many pointers for finish_*() calls */
171 void **finish_pointers;
172
173 /* allocated with stripe_npages-many bits for finish_*() calls */
174 unsigned long *finish_pbitmap;
175};
176
177static int __raid56_parity_recover(struct btrfs_raid_bio *rbio);
178static noinline void finish_rmw(struct btrfs_raid_bio *rbio);
179static void rmw_work(struct btrfs_work *work);
180static void read_rebuild_work(struct btrfs_work *work);
181static int fail_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio);
182static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed);
183static void __free_raid_bio(struct btrfs_raid_bio *rbio);
184static void index_rbio_pages(struct btrfs_raid_bio *rbio);
185static int alloc_rbio_pages(struct btrfs_raid_bio *rbio);
186
187static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
188 int need_check);
189static void scrub_parity_work(struct btrfs_work *work);
190
191static void start_async_work(struct btrfs_raid_bio *rbio, btrfs_func_t work_func)
192{
193 btrfs_init_work(&rbio->work, btrfs_rmw_helper, work_func, NULL, NULL);
194 btrfs_queue_work(rbio->fs_info->rmw_workers, &rbio->work);
195}
196
197/*
198 * the stripe hash table is used for locking, and to collect
199 * bios in hopes of making a full stripe
200 */
201int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info)
202{
203 struct btrfs_stripe_hash_table *table;
204 struct btrfs_stripe_hash_table *x;
205 struct btrfs_stripe_hash *cur;
206 struct btrfs_stripe_hash *h;
207 int num_entries = 1 << BTRFS_STRIPE_HASH_TABLE_BITS;
208 int i;
209 int table_size;
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_size = sizeof(*table) + sizeof(*h) * num_entries;
222 table = kvzalloc(table_size, GFP_KERNEL);
223 if (!table)
224 return -ENOMEM;
225
226 spin_lock_init(&table->cache_lock);
227 INIT_LIST_HEAD(&table->stripe_cache);
228
229 h = table->table;
230
231 for (i = 0; i < num_entries; i++) {
232 cur = h + i;
233 INIT_LIST_HEAD(&cur->hash_list);
234 spin_lock_init(&cur->lock);
235 }
236
237 x = cmpxchg(&info->stripe_hash_table, NULL, table);
238 if (x)
239 kvfree(x);
240 return 0;
241}
242
243/*
244 * caching an rbio means to copy anything from the
245 * bio_pages array into the stripe_pages array. We
246 * use the page uptodate bit in the stripe cache array
247 * to indicate if it has valid data
248 *
249 * once the caching is done, we set the cache ready
250 * bit.
251 */
252static void cache_rbio_pages(struct btrfs_raid_bio *rbio)
253{
254 int i;
255 char *s;
256 char *d;
257 int ret;
258
259 ret = alloc_rbio_pages(rbio);
260 if (ret)
261 return;
262
263 for (i = 0; i < rbio->nr_pages; i++) {
264 if (!rbio->bio_pages[i])
265 continue;
266
267 s = kmap(rbio->bio_pages[i]);
268 d = kmap(rbio->stripe_pages[i]);
269
270 copy_page(d, s);
271
272 kunmap(rbio->bio_pages[i]);
273 kunmap(rbio->stripe_pages[i]);
274 SetPageUptodate(rbio->stripe_pages[i]);
275 }
276 set_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
277}
278
279/*
280 * we hash on the first logical address of the stripe
281 */
282static int rbio_bucket(struct btrfs_raid_bio *rbio)
283{
284 u64 num = rbio->bbio->raid_map[0];
285
286 /*
287 * we shift down quite a bit. We're using byte
288 * addressing, and most of the lower bits are zeros.
289 * This tends to upset hash_64, and it consistently
290 * returns just one or two different values.
291 *
292 * shifting off the lower bits fixes things.
293 */
294 return hash_64(num >> 16, BTRFS_STRIPE_HASH_TABLE_BITS);
295}
296
297/*
298 * stealing an rbio means taking all the uptodate pages from the stripe
299 * array in the source rbio and putting them into the destination rbio
300 */
301static void steal_rbio(struct btrfs_raid_bio *src, struct btrfs_raid_bio *dest)
302{
303 int i;
304 struct page *s;
305 struct page *d;
306
307 if (!test_bit(RBIO_CACHE_READY_BIT, &src->flags))
308 return;
309
310 for (i = 0; i < dest->nr_pages; i++) {
311 s = src->stripe_pages[i];
312 if (!s || !PageUptodate(s)) {
313 continue;
314 }
315
316 d = dest->stripe_pages[i];
317 if (d)
318 __free_page(d);
319
320 dest->stripe_pages[i] = s;
321 src->stripe_pages[i] = NULL;
322 }
323}
324
325/*
326 * merging means we take the bio_list from the victim and
327 * splice it into the destination. The victim should
328 * be discarded afterwards.
329 *
330 * must be called with dest->rbio_list_lock held
331 */
332static void merge_rbio(struct btrfs_raid_bio *dest,
333 struct btrfs_raid_bio *victim)
334{
335 bio_list_merge(&dest->bio_list, &victim->bio_list);
336 dest->bio_list_bytes += victim->bio_list_bytes;
337 dest->generic_bio_cnt += victim->generic_bio_cnt;
338 bio_list_init(&victim->bio_list);
339}
340
341/*
342 * used to prune items that are in the cache. The caller
343 * must hold the hash table lock.
344 */
345static void __remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
346{
347 int bucket = rbio_bucket(rbio);
348 struct btrfs_stripe_hash_table *table;
349 struct btrfs_stripe_hash *h;
350 int freeit = 0;
351
352 /*
353 * check the bit again under the hash table lock.
354 */
355 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
356 return;
357
358 table = rbio->fs_info->stripe_hash_table;
359 h = table->table + bucket;
360
361 /* hold the lock for the bucket because we may be
362 * removing it from the hash table
363 */
364 spin_lock(&h->lock);
365
366 /*
367 * hold the lock for the bio list because we need
368 * to make sure the bio list is empty
369 */
370 spin_lock(&rbio->bio_list_lock);
371
372 if (test_and_clear_bit(RBIO_CACHE_BIT, &rbio->flags)) {
373 list_del_init(&rbio->stripe_cache);
374 table->cache_size -= 1;
375 freeit = 1;
376
377 /* if the bio list isn't empty, this rbio is
378 * still involved in an IO. We take it out
379 * of the cache list, and drop the ref that
380 * was held for the list.
381 *
382 * If the bio_list was empty, we also remove
383 * the rbio from the hash_table, and drop
384 * the corresponding ref
385 */
386 if (bio_list_empty(&rbio->bio_list)) {
387 if (!list_empty(&rbio->hash_list)) {
388 list_del_init(&rbio->hash_list);
389 refcount_dec(&rbio->refs);
390 BUG_ON(!list_empty(&rbio->plug_list));
391 }
392 }
393 }
394
395 spin_unlock(&rbio->bio_list_lock);
396 spin_unlock(&h->lock);
397
398 if (freeit)
399 __free_raid_bio(rbio);
400}
401
402/*
403 * prune a given rbio from the cache
404 */
405static void remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
406{
407 struct btrfs_stripe_hash_table *table;
408 unsigned long flags;
409
410 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
411 return;
412
413 table = rbio->fs_info->stripe_hash_table;
414
415 spin_lock_irqsave(&table->cache_lock, flags);
416 __remove_rbio_from_cache(rbio);
417 spin_unlock_irqrestore(&table->cache_lock, flags);
418}
419
420/*
421 * remove everything in the cache
422 */
423static void btrfs_clear_rbio_cache(struct btrfs_fs_info *info)
424{
425 struct btrfs_stripe_hash_table *table;
426 unsigned long flags;
427 struct btrfs_raid_bio *rbio;
428
429 table = info->stripe_hash_table;
430
431 spin_lock_irqsave(&table->cache_lock, flags);
432 while (!list_empty(&table->stripe_cache)) {
433 rbio = list_entry(table->stripe_cache.next,
434 struct btrfs_raid_bio,
435 stripe_cache);
436 __remove_rbio_from_cache(rbio);
437 }
438 spin_unlock_irqrestore(&table->cache_lock, flags);
439}
440
441/*
442 * remove all cached entries and free the hash table
443 * used by unmount
444 */
445void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info)
446{
447 if (!info->stripe_hash_table)
448 return;
449 btrfs_clear_rbio_cache(info);
450 kvfree(info->stripe_hash_table);
451 info->stripe_hash_table = NULL;
452}
453
454/*
455 * insert an rbio into the stripe cache. It
456 * must have already been prepared by calling
457 * cache_rbio_pages
458 *
459 * If this rbio was already cached, it gets
460 * moved to the front of the lru.
461 *
462 * If the size of the rbio cache is too big, we
463 * prune an item.
464 */
465static void cache_rbio(struct btrfs_raid_bio *rbio)
466{
467 struct btrfs_stripe_hash_table *table;
468 unsigned long flags;
469
470 if (!test_bit(RBIO_CACHE_READY_BIT, &rbio->flags))
471 return;
472
473 table = rbio->fs_info->stripe_hash_table;
474
475 spin_lock_irqsave(&table->cache_lock, flags);
476 spin_lock(&rbio->bio_list_lock);
477
478 /* bump our ref if we were not in the list before */
479 if (!test_and_set_bit(RBIO_CACHE_BIT, &rbio->flags))
480 refcount_inc(&rbio->refs);
481
482 if (!list_empty(&rbio->stripe_cache)){
483 list_move(&rbio->stripe_cache, &table->stripe_cache);
484 } else {
485 list_add(&rbio->stripe_cache, &table->stripe_cache);
486 table->cache_size += 1;
487 }
488
489 spin_unlock(&rbio->bio_list_lock);
490
491 if (table->cache_size > RBIO_CACHE_SIZE) {
492 struct btrfs_raid_bio *found;
493
494 found = list_entry(table->stripe_cache.prev,
495 struct btrfs_raid_bio,
496 stripe_cache);
497
498 if (found != rbio)
499 __remove_rbio_from_cache(found);
500 }
501
502 spin_unlock_irqrestore(&table->cache_lock, flags);
503}
504
505/*
506 * helper function to run the xor_blocks api. It is only
507 * able to do MAX_XOR_BLOCKS at a time, so we need to
508 * loop through.
509 */
510static void run_xor(void **pages, int src_cnt, ssize_t len)
511{
512 int src_off = 0;
513 int xor_src_cnt = 0;
514 void *dest = pages[src_cnt];
515
516 while(src_cnt > 0) {
517 xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS);
518 xor_blocks(xor_src_cnt, len, dest, pages + src_off);
519
520 src_cnt -= xor_src_cnt;
521 src_off += xor_src_cnt;
522 }
523}
524
525/*
526 * Returns true if the bio list inside this rbio covers an entire stripe (no
527 * rmw required).
528 */
529static int rbio_is_full(struct btrfs_raid_bio *rbio)
530{
531 unsigned long flags;
532 unsigned long size = rbio->bio_list_bytes;
533 int ret = 1;
534
535 spin_lock_irqsave(&rbio->bio_list_lock, flags);
536 if (size != rbio->nr_data * rbio->stripe_len)
537 ret = 0;
538 BUG_ON(size > rbio->nr_data * rbio->stripe_len);
539 spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
540
541 return ret;
542}
543
544/*
545 * returns 1 if it is safe to merge two rbios together.
546 * The merging is safe if the two rbios correspond to
547 * the same stripe and if they are both going in the same
548 * direction (read vs write), and if neither one is
549 * locked for final IO
550 *
551 * The caller is responsible for locking such that
552 * rmw_locked is safe to test
553 */
554static int rbio_can_merge(struct btrfs_raid_bio *last,
555 struct btrfs_raid_bio *cur)
556{
557 if (test_bit(RBIO_RMW_LOCKED_BIT, &last->flags) ||
558 test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags))
559 return 0;
560
561 /*
562 * we can't merge with cached rbios, since the
563 * idea is that when we merge the destination
564 * rbio is going to run our IO for us. We can
565 * steal from cached rbios though, other functions
566 * handle that.
567 */
568 if (test_bit(RBIO_CACHE_BIT, &last->flags) ||
569 test_bit(RBIO_CACHE_BIT, &cur->flags))
570 return 0;
571
572 if (last->bbio->raid_map[0] !=
573 cur->bbio->raid_map[0])
574 return 0;
575
576 /* we can't merge with different operations */
577 if (last->operation != cur->operation)
578 return 0;
579 /*
580 * We've need read the full stripe from the drive.
581 * check and repair the parity and write the new results.
582 *
583 * We're not allowed to add any new bios to the
584 * bio list here, anyone else that wants to
585 * change this stripe needs to do their own rmw.
586 */
587 if (last->operation == BTRFS_RBIO_PARITY_SCRUB)
588 return 0;
589
590 if (last->operation == BTRFS_RBIO_REBUILD_MISSING)
591 return 0;
592
593 if (last->operation == BTRFS_RBIO_READ_REBUILD) {
594 int fa = last->faila;
595 int fb = last->failb;
596 int cur_fa = cur->faila;
597 int cur_fb = cur->failb;
598
599 if (last->faila >= last->failb) {
600 fa = last->failb;
601 fb = last->faila;
602 }
603
604 if (cur->faila >= cur->failb) {
605 cur_fa = cur->failb;
606 cur_fb = cur->faila;
607 }
608
609 if (fa != cur_fa || fb != cur_fb)
610 return 0;
611 }
612 return 1;
613}
614
615static int rbio_stripe_page_index(struct btrfs_raid_bio *rbio, int stripe,
616 int index)
617{
618 return stripe * rbio->stripe_npages + index;
619}
620
621/*
622 * these are just the pages from the rbio array, not from anything
623 * the FS sent down to us
624 */
625static struct page *rbio_stripe_page(struct btrfs_raid_bio *rbio, int stripe,
626 int index)
627{
628 return rbio->stripe_pages[rbio_stripe_page_index(rbio, stripe, index)];
629}
630
631/*
632 * helper to index into the pstripe
633 */
634static struct page *rbio_pstripe_page(struct btrfs_raid_bio *rbio, int index)
635{
636 return rbio_stripe_page(rbio, rbio->nr_data, index);
637}
638
639/*
640 * helper to index into the qstripe, returns null
641 * if there is no qstripe
642 */
643static struct page *rbio_qstripe_page(struct btrfs_raid_bio *rbio, int index)
644{
645 if (rbio->nr_data + 1 == rbio->real_stripes)
646 return NULL;
647 return rbio_stripe_page(rbio, rbio->nr_data + 1, index);
648}
649
650/*
651 * The first stripe in the table for a logical address
652 * has the lock. rbios are added in one of three ways:
653 *
654 * 1) Nobody has the stripe locked yet. The rbio is given
655 * the lock and 0 is returned. The caller must start the IO
656 * themselves.
657 *
658 * 2) Someone has the stripe locked, but we're able to merge
659 * with the lock owner. The rbio is freed and the IO will
660 * start automatically along with the existing rbio. 1 is returned.
661 *
662 * 3) Someone has the stripe locked, but we're not able to merge.
663 * The rbio is added to the lock owner's plug list, or merged into
664 * an rbio already on the plug list. When the lock owner unlocks,
665 * the next rbio on the list is run and the IO is started automatically.
666 * 1 is returned
667 *
668 * If we return 0, the caller still owns the rbio and must continue with
669 * IO submission. If we return 1, the caller must assume the rbio has
670 * already been freed.
671 */
672static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
673{
674 int bucket = rbio_bucket(rbio);
675 struct btrfs_stripe_hash *h = rbio->fs_info->stripe_hash_table->table + bucket;
676 struct btrfs_raid_bio *cur;
677 struct btrfs_raid_bio *pending;
678 unsigned long flags;
679 struct btrfs_raid_bio *freeit = NULL;
680 struct btrfs_raid_bio *cache_drop = NULL;
681 int ret = 0;
682
683 spin_lock_irqsave(&h->lock, flags);
684 list_for_each_entry(cur, &h->hash_list, hash_list) {
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 refcount_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 refcount_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 refcount_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 refcount_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 start_async_work(next, read_rebuild_work);
812 else if (next->operation == BTRFS_RBIO_REBUILD_MISSING) {
813 steal_rbio(rbio, next);
814 start_async_work(next, read_rebuild_work);
815 } else if (next->operation == BTRFS_RBIO_WRITE) {
816 steal_rbio(rbio, next);
817 start_async_work(next, rmw_work);
818 } else if (next->operation == BTRFS_RBIO_PARITY_SCRUB) {
819 steal_rbio(rbio, next);
820 start_async_work(next, scrub_parity_work);
821 }
822
823 goto done_nolock;
824 }
825 }
826done:
827 spin_unlock(&rbio->bio_list_lock);
828 spin_unlock_irqrestore(&h->lock, flags);
829
830done_nolock:
831 if (!keep_cache)
832 remove_rbio_from_cache(rbio);
833}
834
835static void __free_raid_bio(struct btrfs_raid_bio *rbio)
836{
837 int i;
838
839 if (!refcount_dec_and_test(&rbio->refs))
840 return;
841
842 WARN_ON(!list_empty(&rbio->stripe_cache));
843 WARN_ON(!list_empty(&rbio->hash_list));
844 WARN_ON(!bio_list_empty(&rbio->bio_list));
845
846 for (i = 0; i < rbio->nr_pages; i++) {
847 if (rbio->stripe_pages[i]) {
848 __free_page(rbio->stripe_pages[i]);
849 rbio->stripe_pages[i] = NULL;
850 }
851 }
852
853 btrfs_put_bbio(rbio->bbio);
854 kfree(rbio);
855}
856
857static void rbio_endio_bio_list(struct bio *cur, blk_status_t err)
858{
859 struct bio *next;
860
861 while (cur) {
862 next = cur->bi_next;
863 cur->bi_next = NULL;
864 cur->bi_status = err;
865 bio_endio(cur);
866 cur = next;
867 }
868}
869
870/*
871 * this frees the rbio and runs through all the bios in the
872 * bio_list and calls end_io on them
873 */
874static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, blk_status_t err)
875{
876 struct bio *cur = bio_list_get(&rbio->bio_list);
877 struct bio *extra;
878
879 if (rbio->generic_bio_cnt)
880 btrfs_bio_counter_sub(rbio->fs_info, rbio->generic_bio_cnt);
881
882 /*
883 * At this moment, rbio->bio_list is empty, however since rbio does not
884 * always have RBIO_RMW_LOCKED_BIT set and rbio is still linked on the
885 * hash list, rbio may be merged with others so that rbio->bio_list
886 * becomes non-empty.
887 * Once unlock_stripe() is done, rbio->bio_list will not be updated any
888 * more and we can call bio_endio() on all queued bios.
889 */
890 unlock_stripe(rbio);
891 extra = bio_list_get(&rbio->bio_list);
892 __free_raid_bio(rbio);
893
894 rbio_endio_bio_list(cur, err);
895 if (extra)
896 rbio_endio_bio_list(extra, err);
897}
898
899/*
900 * end io function used by finish_rmw. When we finally
901 * get here, we've written a full stripe
902 */
903static void raid_write_end_io(struct bio *bio)
904{
905 struct btrfs_raid_bio *rbio = bio->bi_private;
906 blk_status_t err = bio->bi_status;
907 int max_errors;
908
909 if (err)
910 fail_bio_stripe(rbio, bio);
911
912 bio_put(bio);
913
914 if (!atomic_dec_and_test(&rbio->stripes_pending))
915 return;
916
917 err = BLK_STS_OK;
918
919 /* OK, we have read all the stripes we need to. */
920 max_errors = (rbio->operation == BTRFS_RBIO_PARITY_SCRUB) ?
921 0 : rbio->bbio->max_errors;
922 if (atomic_read(&rbio->error) > max_errors)
923 err = BLK_STS_IOERR;
924
925 rbio_orig_end_io(rbio, err);
926}
927
928/*
929 * the read/modify/write code wants to use the original bio for
930 * any pages it included, and then use the rbio for everything
931 * else. This function decides if a given index (stripe number)
932 * and page number in that stripe fall inside the original bio
933 * or the rbio.
934 *
935 * if you set bio_list_only, you'll get a NULL back for any ranges
936 * that are outside the bio_list
937 *
938 * This doesn't take any refs on anything, you get a bare page pointer
939 * and the caller must bump refs as required.
940 *
941 * You must call index_rbio_pages once before you can trust
942 * the answers from this function.
943 */
944static struct page *page_in_rbio(struct btrfs_raid_bio *rbio,
945 int index, int pagenr, int bio_list_only)
946{
947 int chunk_page;
948 struct page *p = NULL;
949
950 chunk_page = index * (rbio->stripe_len >> PAGE_SHIFT) + pagenr;
951
952 spin_lock_irq(&rbio->bio_list_lock);
953 p = rbio->bio_pages[chunk_page];
954 spin_unlock_irq(&rbio->bio_list_lock);
955
956 if (p || bio_list_only)
957 return p;
958
959 return rbio->stripe_pages[chunk_page];
960}
961
962/*
963 * number of pages we need for the entire stripe across all the
964 * drives
965 */
966static unsigned long rbio_nr_pages(unsigned long stripe_len, int nr_stripes)
967{
968 return DIV_ROUND_UP(stripe_len, PAGE_SIZE) * nr_stripes;
969}
970
971/*
972 * allocation and initial setup for the btrfs_raid_bio. Not
973 * this does not allocate any pages for rbio->pages.
974 */
975static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info,
976 struct btrfs_bio *bbio,
977 u64 stripe_len)
978{
979 struct btrfs_raid_bio *rbio;
980 int nr_data = 0;
981 int real_stripes = bbio->num_stripes - bbio->num_tgtdevs;
982 int num_pages = rbio_nr_pages(stripe_len, real_stripes);
983 int stripe_npages = DIV_ROUND_UP(stripe_len, PAGE_SIZE);
984 void *p;
985
986 rbio = kzalloc(sizeof(*rbio) +
987 sizeof(*rbio->stripe_pages) * num_pages +
988 sizeof(*rbio->bio_pages) * num_pages +
989 sizeof(*rbio->finish_pointers) * real_stripes +
990 sizeof(*rbio->dbitmap) * BITS_TO_LONGS(stripe_npages) +
991 sizeof(*rbio->finish_pbitmap) *
992 BITS_TO_LONGS(stripe_npages),
993 GFP_NOFS);
994 if (!rbio)
995 return ERR_PTR(-ENOMEM);
996
997 bio_list_init(&rbio->bio_list);
998 INIT_LIST_HEAD(&rbio->plug_list);
999 spin_lock_init(&rbio->bio_list_lock);
1000 INIT_LIST_HEAD(&rbio->stripe_cache);
1001 INIT_LIST_HEAD(&rbio->hash_list);
1002 rbio->bbio = bbio;
1003 rbio->fs_info = fs_info;
1004 rbio->stripe_len = stripe_len;
1005 rbio->nr_pages = num_pages;
1006 rbio->real_stripes = real_stripes;
1007 rbio->stripe_npages = stripe_npages;
1008 rbio->faila = -1;
1009 rbio->failb = -1;
1010 refcount_set(&rbio->refs, 1);
1011 atomic_set(&rbio->error, 0);
1012 atomic_set(&rbio->stripes_pending, 0);
1013
1014 /*
1015 * the stripe_pages, bio_pages, etc arrays point to the extra
1016 * memory we allocated past the end of the rbio
1017 */
1018 p = rbio + 1;
1019#define CONSUME_ALLOC(ptr, count) do { \
1020 ptr = p; \
1021 p = (unsigned char *)p + sizeof(*(ptr)) * (count); \
1022 } while (0)
1023 CONSUME_ALLOC(rbio->stripe_pages, num_pages);
1024 CONSUME_ALLOC(rbio->bio_pages, num_pages);
1025 CONSUME_ALLOC(rbio->finish_pointers, real_stripes);
1026 CONSUME_ALLOC(rbio->dbitmap, BITS_TO_LONGS(stripe_npages));
1027 CONSUME_ALLOC(rbio->finish_pbitmap, BITS_TO_LONGS(stripe_npages));
1028#undef CONSUME_ALLOC
1029
1030 if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID5)
1031 nr_data = real_stripes - 1;
1032 else if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID6)
1033 nr_data = real_stripes - 2;
1034 else
1035 BUG();
1036
1037 rbio->nr_data = nr_data;
1038 return rbio;
1039}
1040
1041/* allocate pages for all the stripes in the bio, including parity */
1042static int alloc_rbio_pages(struct btrfs_raid_bio *rbio)
1043{
1044 int i;
1045 struct page *page;
1046
1047 for (i = 0; i < rbio->nr_pages; i++) {
1048 if (rbio->stripe_pages[i])
1049 continue;
1050 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1051 if (!page)
1052 return -ENOMEM;
1053 rbio->stripe_pages[i] = page;
1054 }
1055 return 0;
1056}
1057
1058/* only allocate pages for p/q stripes */
1059static int alloc_rbio_parity_pages(struct btrfs_raid_bio *rbio)
1060{
1061 int i;
1062 struct page *page;
1063
1064 i = rbio_stripe_page_index(rbio, rbio->nr_data, 0);
1065
1066 for (; i < rbio->nr_pages; i++) {
1067 if (rbio->stripe_pages[i])
1068 continue;
1069 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1070 if (!page)
1071 return -ENOMEM;
1072 rbio->stripe_pages[i] = page;
1073 }
1074 return 0;
1075}
1076
1077/*
1078 * add a single page from a specific stripe into our list of bios for IO
1079 * this will try to merge into existing bios if possible, and returns
1080 * zero if all went well.
1081 */
1082static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
1083 struct bio_list *bio_list,
1084 struct page *page,
1085 int stripe_nr,
1086 unsigned long page_index,
1087 unsigned long bio_max_len)
1088{
1089 struct bio *last = bio_list->tail;
1090 u64 last_end = 0;
1091 int ret;
1092 struct bio *bio;
1093 struct btrfs_bio_stripe *stripe;
1094 u64 disk_start;
1095
1096 stripe = &rbio->bbio->stripes[stripe_nr];
1097 disk_start = stripe->physical + (page_index << PAGE_SHIFT);
1098
1099 /* if the device is missing, just fail this stripe */
1100 if (!stripe->dev->bdev)
1101 return fail_rbio_index(rbio, stripe_nr);
1102
1103 /* see if we can add this page onto our existing bio */
1104 if (last) {
1105 last_end = (u64)last->bi_iter.bi_sector << 9;
1106 last_end += last->bi_iter.bi_size;
1107
1108 /*
1109 * we can't merge these if they are from different
1110 * devices or if they are not contiguous
1111 */
1112 if (last_end == disk_start && stripe->dev->bdev &&
1113 !last->bi_status &&
1114 last->bi_disk == stripe->dev->bdev->bd_disk &&
1115 last->bi_partno == stripe->dev->bdev->bd_partno) {
1116 ret = bio_add_page(last, page, PAGE_SIZE, 0);
1117 if (ret == PAGE_SIZE)
1118 return 0;
1119 }
1120 }
1121
1122 /* put a new bio on the list */
1123 bio = btrfs_io_bio_alloc(bio_max_len >> PAGE_SHIFT ?: 1);
1124 bio->bi_iter.bi_size = 0;
1125 bio_set_dev(bio, stripe->dev->bdev);
1126 bio->bi_iter.bi_sector = disk_start >> 9;
1127
1128 bio_add_page(bio, page, PAGE_SIZE, 0);
1129 bio_list_add(bio_list, bio);
1130 return 0;
1131}
1132
1133/*
1134 * while we're doing the read/modify/write cycle, we could
1135 * have errors in reading pages off the disk. This checks
1136 * for errors and if we're not able to read the page it'll
1137 * trigger parity reconstruction. The rmw will be finished
1138 * after we've reconstructed the failed stripes
1139 */
1140static void validate_rbio_for_rmw(struct btrfs_raid_bio *rbio)
1141{
1142 if (rbio->faila >= 0 || rbio->failb >= 0) {
1143 BUG_ON(rbio->faila == rbio->real_stripes - 1);
1144 __raid56_parity_recover(rbio);
1145 } else {
1146 finish_rmw(rbio);
1147 }
1148}
1149
1150/*
1151 * helper function to walk our bio list and populate the bio_pages array with
1152 * the result. This seems expensive, but it is faster than constantly
1153 * searching through the bio list as we setup the IO in finish_rmw or stripe
1154 * reconstruction.
1155 *
1156 * This must be called before you trust the answers from page_in_rbio
1157 */
1158static void index_rbio_pages(struct btrfs_raid_bio *rbio)
1159{
1160 struct bio *bio;
1161 u64 start;
1162 unsigned long stripe_offset;
1163 unsigned long page_index;
1164
1165 spin_lock_irq(&rbio->bio_list_lock);
1166 bio_list_for_each(bio, &rbio->bio_list) {
1167 struct bio_vec bvec;
1168 struct bvec_iter iter;
1169 int i = 0;
1170
1171 start = (u64)bio->bi_iter.bi_sector << 9;
1172 stripe_offset = start - rbio->bbio->raid_map[0];
1173 page_index = stripe_offset >> PAGE_SHIFT;
1174
1175 if (bio_flagged(bio, BIO_CLONED))
1176 bio->bi_iter = btrfs_io_bio(bio)->iter;
1177
1178 bio_for_each_segment(bvec, bio, iter) {
1179 rbio->bio_pages[page_index + i] = bvec.bv_page;
1180 i++;
1181 }
1182 }
1183 spin_unlock_irq(&rbio->bio_list_lock);
1184}
1185
1186/*
1187 * this is called from one of two situations. We either
1188 * have a full stripe from the higher layers, or we've read all
1189 * the missing bits off disk.
1190 *
1191 * This will calculate the parity and then send down any
1192 * changed blocks.
1193 */
1194static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
1195{
1196 struct btrfs_bio *bbio = rbio->bbio;
1197 void **pointers = rbio->finish_pointers;
1198 int nr_data = rbio->nr_data;
1199 int stripe;
1200 int pagenr;
1201 int p_stripe = -1;
1202 int q_stripe = -1;
1203 struct bio_list bio_list;
1204 struct bio *bio;
1205 int ret;
1206
1207 bio_list_init(&bio_list);
1208
1209 if (rbio->real_stripes - rbio->nr_data == 1) {
1210 p_stripe = rbio->real_stripes - 1;
1211 } else if (rbio->real_stripes - rbio->nr_data == 2) {
1212 p_stripe = rbio->real_stripes - 2;
1213 q_stripe = rbio->real_stripes - 1;
1214 } else {
1215 BUG();
1216 }
1217
1218 /* at this point we either have a full stripe,
1219 * or we've read the full stripe from the drive.
1220 * recalculate the parity and write the new results.
1221 *
1222 * We're not allowed to add any new bios to the
1223 * bio list here, anyone else that wants to
1224 * change this stripe needs to do their own rmw.
1225 */
1226 spin_lock_irq(&rbio->bio_list_lock);
1227 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1228 spin_unlock_irq(&rbio->bio_list_lock);
1229
1230 atomic_set(&rbio->error, 0);
1231
1232 /*
1233 * now that we've set rmw_locked, run through the
1234 * bio list one last time and map the page pointers
1235 *
1236 * We don't cache full rbios because we're assuming
1237 * the higher layers are unlikely to use this area of
1238 * the disk again soon. If they do use it again,
1239 * hopefully they will send another full bio.
1240 */
1241 index_rbio_pages(rbio);
1242 if (!rbio_is_full(rbio))
1243 cache_rbio_pages(rbio);
1244 else
1245 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
1246
1247 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1248 struct page *p;
1249 /* first collect one page from each data stripe */
1250 for (stripe = 0; stripe < nr_data; stripe++) {
1251 p = page_in_rbio(rbio, stripe, pagenr, 0);
1252 pointers[stripe] = kmap(p);
1253 }
1254
1255 /* then add the parity stripe */
1256 p = rbio_pstripe_page(rbio, pagenr);
1257 SetPageUptodate(p);
1258 pointers[stripe++] = kmap(p);
1259
1260 if (q_stripe != -1) {
1261
1262 /*
1263 * raid6, add the qstripe and call the
1264 * library function to fill in our p/q
1265 */
1266 p = rbio_qstripe_page(rbio, pagenr);
1267 SetPageUptodate(p);
1268 pointers[stripe++] = kmap(p);
1269
1270 raid6_call.gen_syndrome(rbio->real_stripes, PAGE_SIZE,
1271 pointers);
1272 } else {
1273 /* raid5 */
1274 copy_page(pointers[nr_data], pointers[0]);
1275 run_xor(pointers + 1, nr_data - 1, PAGE_SIZE);
1276 }
1277
1278
1279 for (stripe = 0; stripe < rbio->real_stripes; stripe++)
1280 kunmap(page_in_rbio(rbio, stripe, pagenr, 0));
1281 }
1282
1283 /*
1284 * time to start writing. Make bios for everything from the
1285 * higher layers (the bio_list in our rbio) and our p/q. Ignore
1286 * everything else.
1287 */
1288 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1289 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1290 struct page *page;
1291 if (stripe < rbio->nr_data) {
1292 page = page_in_rbio(rbio, stripe, pagenr, 1);
1293 if (!page)
1294 continue;
1295 } else {
1296 page = rbio_stripe_page(rbio, stripe, pagenr);
1297 }
1298
1299 ret = rbio_add_io_page(rbio, &bio_list,
1300 page, stripe, pagenr, rbio->stripe_len);
1301 if (ret)
1302 goto cleanup;
1303 }
1304 }
1305
1306 if (likely(!bbio->num_tgtdevs))
1307 goto write_data;
1308
1309 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1310 if (!bbio->tgtdev_map[stripe])
1311 continue;
1312
1313 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1314 struct page *page;
1315 if (stripe < rbio->nr_data) {
1316 page = page_in_rbio(rbio, stripe, pagenr, 1);
1317 if (!page)
1318 continue;
1319 } else {
1320 page = rbio_stripe_page(rbio, stripe, pagenr);
1321 }
1322
1323 ret = rbio_add_io_page(rbio, &bio_list, page,
1324 rbio->bbio->tgtdev_map[stripe],
1325 pagenr, rbio->stripe_len);
1326 if (ret)
1327 goto cleanup;
1328 }
1329 }
1330
1331write_data:
1332 atomic_set(&rbio->stripes_pending, bio_list_size(&bio_list));
1333 BUG_ON(atomic_read(&rbio->stripes_pending) == 0);
1334
1335 while (1) {
1336 bio = bio_list_pop(&bio_list);
1337 if (!bio)
1338 break;
1339
1340 bio->bi_private = rbio;
1341 bio->bi_end_io = raid_write_end_io;
1342 bio->bi_opf = REQ_OP_WRITE;
1343
1344 submit_bio(bio);
1345 }
1346 return;
1347
1348cleanup:
1349 rbio_orig_end_io(rbio, BLK_STS_IOERR);
1350
1351 while ((bio = bio_list_pop(&bio_list)))
1352 bio_put(bio);
1353}
1354
1355/*
1356 * helper to find the stripe number for a given bio. Used to figure out which
1357 * stripe has failed. This expects the bio to correspond to a physical disk,
1358 * so it looks up based on physical sector numbers.
1359 */
1360static int find_bio_stripe(struct btrfs_raid_bio *rbio,
1361 struct bio *bio)
1362{
1363 u64 physical = bio->bi_iter.bi_sector;
1364 u64 stripe_start;
1365 int i;
1366 struct btrfs_bio_stripe *stripe;
1367
1368 physical <<= 9;
1369
1370 for (i = 0; i < rbio->bbio->num_stripes; i++) {
1371 stripe = &rbio->bbio->stripes[i];
1372 stripe_start = stripe->physical;
1373 if (physical >= stripe_start &&
1374 physical < stripe_start + rbio->stripe_len &&
1375 stripe->dev->bdev &&
1376 bio->bi_disk == stripe->dev->bdev->bd_disk &&
1377 bio->bi_partno == stripe->dev->bdev->bd_partno) {
1378 return i;
1379 }
1380 }
1381 return -1;
1382}
1383
1384/*
1385 * helper to find the stripe number for a given
1386 * bio (before mapping). Used to figure out which stripe has
1387 * failed. This looks up based on logical block numbers.
1388 */
1389static int find_logical_bio_stripe(struct btrfs_raid_bio *rbio,
1390 struct bio *bio)
1391{
1392 u64 logical = bio->bi_iter.bi_sector;
1393 u64 stripe_start;
1394 int i;
1395
1396 logical <<= 9;
1397
1398 for (i = 0; i < rbio->nr_data; i++) {
1399 stripe_start = rbio->bbio->raid_map[i];
1400 if (logical >= stripe_start &&
1401 logical < stripe_start + rbio->stripe_len) {
1402 return i;
1403 }
1404 }
1405 return -1;
1406}
1407
1408/*
1409 * returns -EIO if we had too many failures
1410 */
1411static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed)
1412{
1413 unsigned long flags;
1414 int ret = 0;
1415
1416 spin_lock_irqsave(&rbio->bio_list_lock, flags);
1417
1418 /* we already know this stripe is bad, move on */
1419 if (rbio->faila == failed || rbio->failb == failed)
1420 goto out;
1421
1422 if (rbio->faila == -1) {
1423 /* first failure on this rbio */
1424 rbio->faila = failed;
1425 atomic_inc(&rbio->error);
1426 } else if (rbio->failb == -1) {
1427 /* second failure on this rbio */
1428 rbio->failb = failed;
1429 atomic_inc(&rbio->error);
1430 } else {
1431 ret = -EIO;
1432 }
1433out:
1434 spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
1435
1436 return ret;
1437}
1438
1439/*
1440 * helper to fail a stripe based on a physical disk
1441 * bio.
1442 */
1443static int fail_bio_stripe(struct btrfs_raid_bio *rbio,
1444 struct bio *bio)
1445{
1446 int failed = find_bio_stripe(rbio, bio);
1447
1448 if (failed < 0)
1449 return -EIO;
1450
1451 return fail_rbio_index(rbio, failed);
1452}
1453
1454/*
1455 * this sets each page in the bio uptodate. It should only be used on private
1456 * rbio pages, nothing that comes in from the higher layers
1457 */
1458static void set_bio_pages_uptodate(struct bio *bio)
1459{
1460 struct bio_vec *bvec;
1461 struct bvec_iter_all iter_all;
1462
1463 ASSERT(!bio_flagged(bio, BIO_CLONED));
1464
1465 bio_for_each_segment_all(bvec, bio, iter_all)
1466 SetPageUptodate(bvec->bv_page);
1467}
1468
1469/*
1470 * end io for the read phase of the rmw cycle. All the bios here are physical
1471 * stripe bios we've read from the disk so we can recalculate the parity of the
1472 * stripe.
1473 *
1474 * This will usually kick off finish_rmw once all the bios are read in, but it
1475 * may trigger parity reconstruction if we had any errors along the way
1476 */
1477static void raid_rmw_end_io(struct bio *bio)
1478{
1479 struct btrfs_raid_bio *rbio = bio->bi_private;
1480
1481 if (bio->bi_status)
1482 fail_bio_stripe(rbio, bio);
1483 else
1484 set_bio_pages_uptodate(bio);
1485
1486 bio_put(bio);
1487
1488 if (!atomic_dec_and_test(&rbio->stripes_pending))
1489 return;
1490
1491 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
1492 goto cleanup;
1493
1494 /*
1495 * this will normally call finish_rmw to start our write
1496 * but if there are any failed stripes we'll reconstruct
1497 * from parity first
1498 */
1499 validate_rbio_for_rmw(rbio);
1500 return;
1501
1502cleanup:
1503
1504 rbio_orig_end_io(rbio, BLK_STS_IOERR);
1505}
1506
1507/*
1508 * the stripe must be locked by the caller. It will
1509 * unlock after all the writes are done
1510 */
1511static int raid56_rmw_stripe(struct btrfs_raid_bio *rbio)
1512{
1513 int bios_to_read = 0;
1514 struct bio_list bio_list;
1515 int ret;
1516 int pagenr;
1517 int stripe;
1518 struct bio *bio;
1519
1520 bio_list_init(&bio_list);
1521
1522 ret = alloc_rbio_pages(rbio);
1523 if (ret)
1524 goto cleanup;
1525
1526 index_rbio_pages(rbio);
1527
1528 atomic_set(&rbio->error, 0);
1529 /*
1530 * build a list of bios to read all the missing parts of this
1531 * stripe
1532 */
1533 for (stripe = 0; stripe < rbio->nr_data; stripe++) {
1534 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1535 struct page *page;
1536 /*
1537 * we want to find all the pages missing from
1538 * the rbio and read them from the disk. If
1539 * page_in_rbio finds a page in the bio list
1540 * we don't need to read it off the stripe.
1541 */
1542 page = page_in_rbio(rbio, stripe, pagenr, 1);
1543 if (page)
1544 continue;
1545
1546 page = rbio_stripe_page(rbio, stripe, pagenr);
1547 /*
1548 * the bio cache may have handed us an uptodate
1549 * page. If so, be happy and use it
1550 */
1551 if (PageUptodate(page))
1552 continue;
1553
1554 ret = rbio_add_io_page(rbio, &bio_list, page,
1555 stripe, pagenr, rbio->stripe_len);
1556 if (ret)
1557 goto cleanup;
1558 }
1559 }
1560
1561 bios_to_read = bio_list_size(&bio_list);
1562 if (!bios_to_read) {
1563 /*
1564 * this can happen if others have merged with
1565 * us, it means there is nothing left to read.
1566 * But if there are missing devices it may not be
1567 * safe to do the full stripe write yet.
1568 */
1569 goto finish;
1570 }
1571
1572 /*
1573 * the bbio may be freed once we submit the last bio. Make sure
1574 * not to touch it after that
1575 */
1576 atomic_set(&rbio->stripes_pending, bios_to_read);
1577 while (1) {
1578 bio = bio_list_pop(&bio_list);
1579 if (!bio)
1580 break;
1581
1582 bio->bi_private = rbio;
1583 bio->bi_end_io = raid_rmw_end_io;
1584 bio->bi_opf = REQ_OP_READ;
1585
1586 btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
1587
1588 submit_bio(bio);
1589 }
1590 /* the actual write will happen once the reads are done */
1591 return 0;
1592
1593cleanup:
1594 rbio_orig_end_io(rbio, BLK_STS_IOERR);
1595
1596 while ((bio = bio_list_pop(&bio_list)))
1597 bio_put(bio);
1598
1599 return -EIO;
1600
1601finish:
1602 validate_rbio_for_rmw(rbio);
1603 return 0;
1604}
1605
1606/*
1607 * if the upper layers pass in a full stripe, we thank them by only allocating
1608 * enough pages to hold the parity, and sending it all down quickly.
1609 */
1610static int full_stripe_write(struct btrfs_raid_bio *rbio)
1611{
1612 int ret;
1613
1614 ret = alloc_rbio_parity_pages(rbio);
1615 if (ret) {
1616 __free_raid_bio(rbio);
1617 return ret;
1618 }
1619
1620 ret = lock_stripe_add(rbio);
1621 if (ret == 0)
1622 finish_rmw(rbio);
1623 return 0;
1624}
1625
1626/*
1627 * partial stripe writes get handed over to async helpers.
1628 * We're really hoping to merge a few more writes into this
1629 * rbio before calculating new parity
1630 */
1631static int partial_stripe_write(struct btrfs_raid_bio *rbio)
1632{
1633 int ret;
1634
1635 ret = lock_stripe_add(rbio);
1636 if (ret == 0)
1637 start_async_work(rbio, rmw_work);
1638 return 0;
1639}
1640
1641/*
1642 * sometimes while we were reading from the drive to
1643 * recalculate parity, enough new bios come into create
1644 * a full stripe. So we do a check here to see if we can
1645 * go directly to finish_rmw
1646 */
1647static int __raid56_parity_write(struct btrfs_raid_bio *rbio)
1648{
1649 /* head off into rmw land if we don't have a full stripe */
1650 if (!rbio_is_full(rbio))
1651 return partial_stripe_write(rbio);
1652 return full_stripe_write(rbio);
1653}
1654
1655/*
1656 * We use plugging call backs to collect full stripes.
1657 * Any time we get a partial stripe write while plugged
1658 * we collect it into a list. When the unplug comes down,
1659 * we sort the list by logical block number and merge
1660 * everything we can into the same rbios
1661 */
1662struct btrfs_plug_cb {
1663 struct blk_plug_cb cb;
1664 struct btrfs_fs_info *info;
1665 struct list_head rbio_list;
1666 struct btrfs_work work;
1667};
1668
1669/*
1670 * rbios on the plug list are sorted for easier merging.
1671 */
1672static int plug_cmp(void *priv, struct list_head *a, struct list_head *b)
1673{
1674 struct btrfs_raid_bio *ra = container_of(a, struct btrfs_raid_bio,
1675 plug_list);
1676 struct btrfs_raid_bio *rb = container_of(b, struct btrfs_raid_bio,
1677 plug_list);
1678 u64 a_sector = ra->bio_list.head->bi_iter.bi_sector;
1679 u64 b_sector = rb->bio_list.head->bi_iter.bi_sector;
1680
1681 if (a_sector < b_sector)
1682 return -1;
1683 if (a_sector > b_sector)
1684 return 1;
1685 return 0;
1686}
1687
1688static void run_plug(struct btrfs_plug_cb *plug)
1689{
1690 struct btrfs_raid_bio *cur;
1691 struct btrfs_raid_bio *last = NULL;
1692
1693 /*
1694 * sort our plug list then try to merge
1695 * everything we can in hopes of creating full
1696 * stripes.
1697 */
1698 list_sort(NULL, &plug->rbio_list, plug_cmp);
1699 while (!list_empty(&plug->rbio_list)) {
1700 cur = list_entry(plug->rbio_list.next,
1701 struct btrfs_raid_bio, plug_list);
1702 list_del_init(&cur->plug_list);
1703
1704 if (rbio_is_full(cur)) {
1705 int ret;
1706
1707 /* we have a full stripe, send it down */
1708 ret = full_stripe_write(cur);
1709 BUG_ON(ret);
1710 continue;
1711 }
1712 if (last) {
1713 if (rbio_can_merge(last, cur)) {
1714 merge_rbio(last, cur);
1715 __free_raid_bio(cur);
1716 continue;
1717
1718 }
1719 __raid56_parity_write(last);
1720 }
1721 last = cur;
1722 }
1723 if (last) {
1724 __raid56_parity_write(last);
1725 }
1726 kfree(plug);
1727}
1728
1729/*
1730 * if the unplug comes from schedule, we have to push the
1731 * work off to a helper thread
1732 */
1733static void unplug_work(struct btrfs_work *work)
1734{
1735 struct btrfs_plug_cb *plug;
1736 plug = container_of(work, struct btrfs_plug_cb, work);
1737 run_plug(plug);
1738}
1739
1740static void btrfs_raid_unplug(struct blk_plug_cb *cb, bool from_schedule)
1741{
1742 struct btrfs_plug_cb *plug;
1743 plug = container_of(cb, struct btrfs_plug_cb, cb);
1744
1745 if (from_schedule) {
1746 btrfs_init_work(&plug->work, btrfs_rmw_helper,
1747 unplug_work, NULL, NULL);
1748 btrfs_queue_work(plug->info->rmw_workers,
1749 &plug->work);
1750 return;
1751 }
1752 run_plug(plug);
1753}
1754
1755/*
1756 * our main entry point for writes from the rest of the FS.
1757 */
1758int raid56_parity_write(struct btrfs_fs_info *fs_info, struct bio *bio,
1759 struct btrfs_bio *bbio, u64 stripe_len)
1760{
1761 struct btrfs_raid_bio *rbio;
1762 struct btrfs_plug_cb *plug = NULL;
1763 struct blk_plug_cb *cb;
1764 int ret;
1765
1766 rbio = alloc_rbio(fs_info, bbio, stripe_len);
1767 if (IS_ERR(rbio)) {
1768 btrfs_put_bbio(bbio);
1769 return PTR_ERR(rbio);
1770 }
1771 bio_list_add(&rbio->bio_list, bio);
1772 rbio->bio_list_bytes = bio->bi_iter.bi_size;
1773 rbio->operation = BTRFS_RBIO_WRITE;
1774
1775 btrfs_bio_counter_inc_noblocked(fs_info);
1776 rbio->generic_bio_cnt = 1;
1777
1778 /*
1779 * don't plug on full rbios, just get them out the door
1780 * as quickly as we can
1781 */
1782 if (rbio_is_full(rbio)) {
1783 ret = full_stripe_write(rbio);
1784 if (ret)
1785 btrfs_bio_counter_dec(fs_info);
1786 return ret;
1787 }
1788
1789 cb = blk_check_plugged(btrfs_raid_unplug, fs_info, sizeof(*plug));
1790 if (cb) {
1791 plug = container_of(cb, struct btrfs_plug_cb, cb);
1792 if (!plug->info) {
1793 plug->info = fs_info;
1794 INIT_LIST_HEAD(&plug->rbio_list);
1795 }
1796 list_add_tail(&rbio->plug_list, &plug->rbio_list);
1797 ret = 0;
1798 } else {
1799 ret = __raid56_parity_write(rbio);
1800 if (ret)
1801 btrfs_bio_counter_dec(fs_info);
1802 }
1803 return ret;
1804}
1805
1806/*
1807 * all parity reconstruction happens here. We've read in everything
1808 * we can find from the drives and this does the heavy lifting of
1809 * sorting the good from the bad.
1810 */
1811static void __raid_recover_end_io(struct btrfs_raid_bio *rbio)
1812{
1813 int pagenr, stripe;
1814 void **pointers;
1815 int faila = -1, failb = -1;
1816 struct page *page;
1817 blk_status_t err;
1818 int i;
1819
1820 pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
1821 if (!pointers) {
1822 err = BLK_STS_RESOURCE;
1823 goto cleanup_io;
1824 }
1825
1826 faila = rbio->faila;
1827 failb = rbio->failb;
1828
1829 if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1830 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) {
1831 spin_lock_irq(&rbio->bio_list_lock);
1832 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1833 spin_unlock_irq(&rbio->bio_list_lock);
1834 }
1835
1836 index_rbio_pages(rbio);
1837
1838 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1839 /*
1840 * Now we just use bitmap to mark the horizontal stripes in
1841 * which we have data when doing parity scrub.
1842 */
1843 if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB &&
1844 !test_bit(pagenr, rbio->dbitmap))
1845 continue;
1846
1847 /* setup our array of pointers with pages
1848 * from each stripe
1849 */
1850 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1851 /*
1852 * if we're rebuilding a read, we have to use
1853 * pages from the bio list
1854 */
1855 if ((rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1856 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) &&
1857 (stripe == faila || stripe == failb)) {
1858 page = page_in_rbio(rbio, stripe, pagenr, 0);
1859 } else {
1860 page = rbio_stripe_page(rbio, stripe, pagenr);
1861 }
1862 pointers[stripe] = kmap(page);
1863 }
1864
1865 /* all raid6 handling here */
1866 if (rbio->bbio->map_type & BTRFS_BLOCK_GROUP_RAID6) {
1867 /*
1868 * single failure, rebuild from parity raid5
1869 * style
1870 */
1871 if (failb < 0) {
1872 if (faila == rbio->nr_data) {
1873 /*
1874 * Just the P stripe has failed, without
1875 * a bad data or Q stripe.
1876 * TODO, we should redo the xor here.
1877 */
1878 err = BLK_STS_IOERR;
1879 goto cleanup;
1880 }
1881 /*
1882 * a single failure in raid6 is rebuilt
1883 * in the pstripe code below
1884 */
1885 goto pstripe;
1886 }
1887
1888 /* make sure our ps and qs are in order */
1889 if (faila > failb) {
1890 int tmp = failb;
1891 failb = faila;
1892 faila = tmp;
1893 }
1894
1895 /* if the q stripe is failed, do a pstripe reconstruction
1896 * from the xors.
1897 * If both the q stripe and the P stripe are failed, we're
1898 * here due to a crc mismatch and we can't give them the
1899 * data they want
1900 */
1901 if (rbio->bbio->raid_map[failb] == RAID6_Q_STRIPE) {
1902 if (rbio->bbio->raid_map[faila] ==
1903 RAID5_P_STRIPE) {
1904 err = BLK_STS_IOERR;
1905 goto cleanup;
1906 }
1907 /*
1908 * otherwise we have one bad data stripe and
1909 * a good P stripe. raid5!
1910 */
1911 goto pstripe;
1912 }
1913
1914 if (rbio->bbio->raid_map[failb] == RAID5_P_STRIPE) {
1915 raid6_datap_recov(rbio->real_stripes,
1916 PAGE_SIZE, faila, pointers);
1917 } else {
1918 raid6_2data_recov(rbio->real_stripes,
1919 PAGE_SIZE, faila, failb,
1920 pointers);
1921 }
1922 } else {
1923 void *p;
1924
1925 /* rebuild from P stripe here (raid5 or raid6) */
1926 BUG_ON(failb != -1);
1927pstripe:
1928 /* Copy parity block into failed block to start with */
1929 copy_page(pointers[faila], pointers[rbio->nr_data]);
1930
1931 /* rearrange the pointer array */
1932 p = pointers[faila];
1933 for (stripe = faila; stripe < rbio->nr_data - 1; stripe++)
1934 pointers[stripe] = pointers[stripe + 1];
1935 pointers[rbio->nr_data - 1] = p;
1936
1937 /* xor in the rest */
1938 run_xor(pointers, rbio->nr_data - 1, PAGE_SIZE);
1939 }
1940 /* if we're doing this rebuild as part of an rmw, go through
1941 * and set all of our private rbio pages in the
1942 * failed stripes as uptodate. This way finish_rmw will
1943 * know they can be trusted. If this was a read reconstruction,
1944 * other endio functions will fiddle the uptodate bits
1945 */
1946 if (rbio->operation == BTRFS_RBIO_WRITE) {
1947 for (i = 0; i < rbio->stripe_npages; i++) {
1948 if (faila != -1) {
1949 page = rbio_stripe_page(rbio, faila, i);
1950 SetPageUptodate(page);
1951 }
1952 if (failb != -1) {
1953 page = rbio_stripe_page(rbio, failb, i);
1954 SetPageUptodate(page);
1955 }
1956 }
1957 }
1958 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1959 /*
1960 * if we're rebuilding a read, we have to use
1961 * pages from the bio list
1962 */
1963 if ((rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1964 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) &&
1965 (stripe == faila || stripe == failb)) {
1966 page = page_in_rbio(rbio, stripe, pagenr, 0);
1967 } else {
1968 page = rbio_stripe_page(rbio, stripe, pagenr);
1969 }
1970 kunmap(page);
1971 }
1972 }
1973
1974 err = BLK_STS_OK;
1975cleanup:
1976 kfree(pointers);
1977
1978cleanup_io:
1979 /*
1980 * Similar to READ_REBUILD, REBUILD_MISSING at this point also has a
1981 * valid rbio which is consistent with ondisk content, thus such a
1982 * valid rbio can be cached to avoid further disk reads.
1983 */
1984 if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1985 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) {
1986 /*
1987 * - In case of two failures, where rbio->failb != -1:
1988 *
1989 * Do not cache this rbio since the above read reconstruction
1990 * (raid6_datap_recov() or raid6_2data_recov()) may have
1991 * changed some content of stripes which are not identical to
1992 * on-disk content any more, otherwise, a later write/recover
1993 * may steal stripe_pages from this rbio and end up with
1994 * corruptions or rebuild failures.
1995 *
1996 * - In case of single failure, where rbio->failb == -1:
1997 *
1998 * Cache this rbio iff the above read reconstruction is
1999 * executed without problems.
2000 */
2001 if (err == BLK_STS_OK && rbio->failb < 0)
2002 cache_rbio_pages(rbio);
2003 else
2004 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
2005
2006 rbio_orig_end_io(rbio, err);
2007 } else if (err == BLK_STS_OK) {
2008 rbio->faila = -1;
2009 rbio->failb = -1;
2010
2011 if (rbio->operation == BTRFS_RBIO_WRITE)
2012 finish_rmw(rbio);
2013 else if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB)
2014 finish_parity_scrub(rbio, 0);
2015 else
2016 BUG();
2017 } else {
2018 rbio_orig_end_io(rbio, err);
2019 }
2020}
2021
2022/*
2023 * This is called only for stripes we've read from disk to
2024 * reconstruct the parity.
2025 */
2026static void raid_recover_end_io(struct bio *bio)
2027{
2028 struct btrfs_raid_bio *rbio = bio->bi_private;
2029
2030 /*
2031 * we only read stripe pages off the disk, set them
2032 * up to date if there were no errors
2033 */
2034 if (bio->bi_status)
2035 fail_bio_stripe(rbio, bio);
2036 else
2037 set_bio_pages_uptodate(bio);
2038 bio_put(bio);
2039
2040 if (!atomic_dec_and_test(&rbio->stripes_pending))
2041 return;
2042
2043 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
2044 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2045 else
2046 __raid_recover_end_io(rbio);
2047}
2048
2049/*
2050 * reads everything we need off the disk to reconstruct
2051 * the parity. endio handlers trigger final reconstruction
2052 * when the IO is done.
2053 *
2054 * This is used both for reads from the higher layers and for
2055 * parity construction required to finish a rmw cycle.
2056 */
2057static int __raid56_parity_recover(struct btrfs_raid_bio *rbio)
2058{
2059 int bios_to_read = 0;
2060 struct bio_list bio_list;
2061 int ret;
2062 int pagenr;
2063 int stripe;
2064 struct bio *bio;
2065
2066 bio_list_init(&bio_list);
2067
2068 ret = alloc_rbio_pages(rbio);
2069 if (ret)
2070 goto cleanup;
2071
2072 atomic_set(&rbio->error, 0);
2073
2074 /*
2075 * read everything that hasn't failed. Thanks to the
2076 * stripe cache, it is possible that some or all of these
2077 * pages are going to be uptodate.
2078 */
2079 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
2080 if (rbio->faila == stripe || rbio->failb == stripe) {
2081 atomic_inc(&rbio->error);
2082 continue;
2083 }
2084
2085 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
2086 struct page *p;
2087
2088 /*
2089 * the rmw code may have already read this
2090 * page in
2091 */
2092 p = rbio_stripe_page(rbio, stripe, pagenr);
2093 if (PageUptodate(p))
2094 continue;
2095
2096 ret = rbio_add_io_page(rbio, &bio_list,
2097 rbio_stripe_page(rbio, stripe, pagenr),
2098 stripe, pagenr, rbio->stripe_len);
2099 if (ret < 0)
2100 goto cleanup;
2101 }
2102 }
2103
2104 bios_to_read = bio_list_size(&bio_list);
2105 if (!bios_to_read) {
2106 /*
2107 * we might have no bios to read just because the pages
2108 * were up to date, or we might have no bios to read because
2109 * the devices were gone.
2110 */
2111 if (atomic_read(&rbio->error) <= rbio->bbio->max_errors) {
2112 __raid_recover_end_io(rbio);
2113 goto out;
2114 } else {
2115 goto cleanup;
2116 }
2117 }
2118
2119 /*
2120 * the bbio may be freed once we submit the last bio. Make sure
2121 * not to touch it after that
2122 */
2123 atomic_set(&rbio->stripes_pending, bios_to_read);
2124 while (1) {
2125 bio = bio_list_pop(&bio_list);
2126 if (!bio)
2127 break;
2128
2129 bio->bi_private = rbio;
2130 bio->bi_end_io = raid_recover_end_io;
2131 bio->bi_opf = REQ_OP_READ;
2132
2133 btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
2134
2135 submit_bio(bio);
2136 }
2137out:
2138 return 0;
2139
2140cleanup:
2141 if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
2142 rbio->operation == BTRFS_RBIO_REBUILD_MISSING)
2143 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2144
2145 while ((bio = bio_list_pop(&bio_list)))
2146 bio_put(bio);
2147
2148 return -EIO;
2149}
2150
2151/*
2152 * the main entry point for reads from the higher layers. This
2153 * is really only called when the normal read path had a failure,
2154 * so we assume the bio they send down corresponds to a failed part
2155 * of the drive.
2156 */
2157int raid56_parity_recover(struct btrfs_fs_info *fs_info, struct bio *bio,
2158 struct btrfs_bio *bbio, u64 stripe_len,
2159 int mirror_num, int generic_io)
2160{
2161 struct btrfs_raid_bio *rbio;
2162 int ret;
2163
2164 if (generic_io) {
2165 ASSERT(bbio->mirror_num == mirror_num);
2166 btrfs_io_bio(bio)->mirror_num = mirror_num;
2167 }
2168
2169 rbio = alloc_rbio(fs_info, bbio, stripe_len);
2170 if (IS_ERR(rbio)) {
2171 if (generic_io)
2172 btrfs_put_bbio(bbio);
2173 return PTR_ERR(rbio);
2174 }
2175
2176 rbio->operation = BTRFS_RBIO_READ_REBUILD;
2177 bio_list_add(&rbio->bio_list, bio);
2178 rbio->bio_list_bytes = bio->bi_iter.bi_size;
2179
2180 rbio->faila = find_logical_bio_stripe(rbio, bio);
2181 if (rbio->faila == -1) {
2182 btrfs_warn(fs_info,
2183 "%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)",
2184 __func__, (u64)bio->bi_iter.bi_sector << 9,
2185 (u64)bio->bi_iter.bi_size, bbio->map_type);
2186 if (generic_io)
2187 btrfs_put_bbio(bbio);
2188 kfree(rbio);
2189 return -EIO;
2190 }
2191
2192 if (generic_io) {
2193 btrfs_bio_counter_inc_noblocked(fs_info);
2194 rbio->generic_bio_cnt = 1;
2195 } else {
2196 btrfs_get_bbio(bbio);
2197 }
2198
2199 /*
2200 * Loop retry:
2201 * for 'mirror == 2', reconstruct from all other stripes.
2202 * for 'mirror_num > 2', select a stripe to fail on every retry.
2203 */
2204 if (mirror_num > 2) {
2205 /*
2206 * 'mirror == 3' is to fail the p stripe and
2207 * reconstruct from the q stripe. 'mirror > 3' is to
2208 * fail a data stripe and reconstruct from p+q stripe.
2209 */
2210 rbio->failb = rbio->real_stripes - (mirror_num - 1);
2211 ASSERT(rbio->failb > 0);
2212 if (rbio->failb <= rbio->faila)
2213 rbio->failb--;
2214 }
2215
2216 ret = lock_stripe_add(rbio);
2217
2218 /*
2219 * __raid56_parity_recover will end the bio with
2220 * any errors it hits. We don't want to return
2221 * its error value up the stack because our caller
2222 * will end up calling bio_endio with any nonzero
2223 * return
2224 */
2225 if (ret == 0)
2226 __raid56_parity_recover(rbio);
2227 /*
2228 * our rbio has been added to the list of
2229 * rbios that will be handled after the
2230 * currently lock owner is done
2231 */
2232 return 0;
2233
2234}
2235
2236static void rmw_work(struct btrfs_work *work)
2237{
2238 struct btrfs_raid_bio *rbio;
2239
2240 rbio = container_of(work, struct btrfs_raid_bio, work);
2241 raid56_rmw_stripe(rbio);
2242}
2243
2244static void read_rebuild_work(struct btrfs_work *work)
2245{
2246 struct btrfs_raid_bio *rbio;
2247
2248 rbio = container_of(work, struct btrfs_raid_bio, work);
2249 __raid56_parity_recover(rbio);
2250}
2251
2252/*
2253 * The following code is used to scrub/replace the parity stripe
2254 *
2255 * Caller must have already increased bio_counter for getting @bbio.
2256 *
2257 * Note: We need make sure all the pages that add into the scrub/replace
2258 * raid bio are correct and not be changed during the scrub/replace. That
2259 * is those pages just hold metadata or file data with checksum.
2260 */
2261
2262struct btrfs_raid_bio *
2263raid56_parity_alloc_scrub_rbio(struct btrfs_fs_info *fs_info, struct bio *bio,
2264 struct btrfs_bio *bbio, u64 stripe_len,
2265 struct btrfs_device *scrub_dev,
2266 unsigned long *dbitmap, int stripe_nsectors)
2267{
2268 struct btrfs_raid_bio *rbio;
2269 int i;
2270
2271 rbio = alloc_rbio(fs_info, bbio, stripe_len);
2272 if (IS_ERR(rbio))
2273 return NULL;
2274 bio_list_add(&rbio->bio_list, bio);
2275 /*
2276 * This is a special bio which is used to hold the completion handler
2277 * and make the scrub rbio is similar to the other types
2278 */
2279 ASSERT(!bio->bi_iter.bi_size);
2280 rbio->operation = BTRFS_RBIO_PARITY_SCRUB;
2281
2282 /*
2283 * After mapping bbio with BTRFS_MAP_WRITE, parities have been sorted
2284 * to the end position, so this search can start from the first parity
2285 * stripe.
2286 */
2287 for (i = rbio->nr_data; i < rbio->real_stripes; i++) {
2288 if (bbio->stripes[i].dev == scrub_dev) {
2289 rbio->scrubp = i;
2290 break;
2291 }
2292 }
2293 ASSERT(i < rbio->real_stripes);
2294
2295 /* Now we just support the sectorsize equals to page size */
2296 ASSERT(fs_info->sectorsize == PAGE_SIZE);
2297 ASSERT(rbio->stripe_npages == stripe_nsectors);
2298 bitmap_copy(rbio->dbitmap, dbitmap, stripe_nsectors);
2299
2300 /*
2301 * We have already increased bio_counter when getting bbio, record it
2302 * so we can free it at rbio_orig_end_io().
2303 */
2304 rbio->generic_bio_cnt = 1;
2305
2306 return rbio;
2307}
2308
2309/* Used for both parity scrub and missing. */
2310void raid56_add_scrub_pages(struct btrfs_raid_bio *rbio, struct page *page,
2311 u64 logical)
2312{
2313 int stripe_offset;
2314 int index;
2315
2316 ASSERT(logical >= rbio->bbio->raid_map[0]);
2317 ASSERT(logical + PAGE_SIZE <= rbio->bbio->raid_map[0] +
2318 rbio->stripe_len * rbio->nr_data);
2319 stripe_offset = (int)(logical - rbio->bbio->raid_map[0]);
2320 index = stripe_offset >> PAGE_SHIFT;
2321 rbio->bio_pages[index] = page;
2322}
2323
2324/*
2325 * We just scrub the parity that we have correct data on the same horizontal,
2326 * so we needn't allocate all pages for all the stripes.
2327 */
2328static int alloc_rbio_essential_pages(struct btrfs_raid_bio *rbio)
2329{
2330 int i;
2331 int bit;
2332 int index;
2333 struct page *page;
2334
2335 for_each_set_bit(bit, rbio->dbitmap, rbio->stripe_npages) {
2336 for (i = 0; i < rbio->real_stripes; i++) {
2337 index = i * rbio->stripe_npages + bit;
2338 if (rbio->stripe_pages[index])
2339 continue;
2340
2341 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2342 if (!page)
2343 return -ENOMEM;
2344 rbio->stripe_pages[index] = page;
2345 }
2346 }
2347 return 0;
2348}
2349
2350static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
2351 int need_check)
2352{
2353 struct btrfs_bio *bbio = rbio->bbio;
2354 void **pointers = rbio->finish_pointers;
2355 unsigned long *pbitmap = rbio->finish_pbitmap;
2356 int nr_data = rbio->nr_data;
2357 int stripe;
2358 int pagenr;
2359 int p_stripe = -1;
2360 int q_stripe = -1;
2361 struct page *p_page = NULL;
2362 struct page *q_page = NULL;
2363 struct bio_list bio_list;
2364 struct bio *bio;
2365 int is_replace = 0;
2366 int ret;
2367
2368 bio_list_init(&bio_list);
2369
2370 if (rbio->real_stripes - rbio->nr_data == 1) {
2371 p_stripe = rbio->real_stripes - 1;
2372 } else if (rbio->real_stripes - rbio->nr_data == 2) {
2373 p_stripe = rbio->real_stripes - 2;
2374 q_stripe = rbio->real_stripes - 1;
2375 } else {
2376 BUG();
2377 }
2378
2379 if (bbio->num_tgtdevs && bbio->tgtdev_map[rbio->scrubp]) {
2380 is_replace = 1;
2381 bitmap_copy(pbitmap, rbio->dbitmap, rbio->stripe_npages);
2382 }
2383
2384 /*
2385 * Because the higher layers(scrubber) are unlikely to
2386 * use this area of the disk again soon, so don't cache
2387 * it.
2388 */
2389 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
2390
2391 if (!need_check)
2392 goto writeback;
2393
2394 p_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2395 if (!p_page)
2396 goto cleanup;
2397 SetPageUptodate(p_page);
2398
2399 if (q_stripe != -1) {
2400 q_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2401 if (!q_page) {
2402 __free_page(p_page);
2403 goto cleanup;
2404 }
2405 SetPageUptodate(q_page);
2406 }
2407
2408 atomic_set(&rbio->error, 0);
2409
2410 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2411 struct page *p;
2412 void *parity;
2413 /* first collect one page from each data stripe */
2414 for (stripe = 0; stripe < nr_data; stripe++) {
2415 p = page_in_rbio(rbio, stripe, pagenr, 0);
2416 pointers[stripe] = kmap(p);
2417 }
2418
2419 /* then add the parity stripe */
2420 pointers[stripe++] = kmap(p_page);
2421
2422 if (q_stripe != -1) {
2423
2424 /*
2425 * raid6, add the qstripe and call the
2426 * library function to fill in our p/q
2427 */
2428 pointers[stripe++] = kmap(q_page);
2429
2430 raid6_call.gen_syndrome(rbio->real_stripes, PAGE_SIZE,
2431 pointers);
2432 } else {
2433 /* raid5 */
2434 copy_page(pointers[nr_data], pointers[0]);
2435 run_xor(pointers + 1, nr_data - 1, PAGE_SIZE);
2436 }
2437
2438 /* Check scrubbing parity and repair it */
2439 p = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2440 parity = kmap(p);
2441 if (memcmp(parity, pointers[rbio->scrubp], PAGE_SIZE))
2442 copy_page(parity, pointers[rbio->scrubp]);
2443 else
2444 /* Parity is right, needn't writeback */
2445 bitmap_clear(rbio->dbitmap, pagenr, 1);
2446 kunmap(p);
2447
2448 for (stripe = 0; stripe < nr_data; stripe++)
2449 kunmap(page_in_rbio(rbio, stripe, pagenr, 0));
2450 kunmap(p_page);
2451 }
2452
2453 __free_page(p_page);
2454 if (q_page)
2455 __free_page(q_page);
2456
2457writeback:
2458 /*
2459 * time to start writing. Make bios for everything from the
2460 * higher layers (the bio_list in our rbio) and our p/q. Ignore
2461 * everything else.
2462 */
2463 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2464 struct page *page;
2465
2466 page = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2467 ret = rbio_add_io_page(rbio, &bio_list,
2468 page, rbio->scrubp, pagenr, rbio->stripe_len);
2469 if (ret)
2470 goto cleanup;
2471 }
2472
2473 if (!is_replace)
2474 goto submit_write;
2475
2476 for_each_set_bit(pagenr, pbitmap, rbio->stripe_npages) {
2477 struct page *page;
2478
2479 page = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2480 ret = rbio_add_io_page(rbio, &bio_list, page,
2481 bbio->tgtdev_map[rbio->scrubp],
2482 pagenr, rbio->stripe_len);
2483 if (ret)
2484 goto cleanup;
2485 }
2486
2487submit_write:
2488 nr_data = bio_list_size(&bio_list);
2489 if (!nr_data) {
2490 /* Every parity is right */
2491 rbio_orig_end_io(rbio, BLK_STS_OK);
2492 return;
2493 }
2494
2495 atomic_set(&rbio->stripes_pending, nr_data);
2496
2497 while (1) {
2498 bio = bio_list_pop(&bio_list);
2499 if (!bio)
2500 break;
2501
2502 bio->bi_private = rbio;
2503 bio->bi_end_io = raid_write_end_io;
2504 bio->bi_opf = REQ_OP_WRITE;
2505
2506 submit_bio(bio);
2507 }
2508 return;
2509
2510cleanup:
2511 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2512
2513 while ((bio = bio_list_pop(&bio_list)))
2514 bio_put(bio);
2515}
2516
2517static inline int is_data_stripe(struct btrfs_raid_bio *rbio, int stripe)
2518{
2519 if (stripe >= 0 && stripe < rbio->nr_data)
2520 return 1;
2521 return 0;
2522}
2523
2524/*
2525 * While we're doing the parity check and repair, we could have errors
2526 * in reading pages off the disk. This checks for errors and if we're
2527 * not able to read the page it'll trigger parity reconstruction. The
2528 * parity scrub will be finished after we've reconstructed the failed
2529 * stripes
2530 */
2531static void validate_rbio_for_parity_scrub(struct btrfs_raid_bio *rbio)
2532{
2533 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
2534 goto cleanup;
2535
2536 if (rbio->faila >= 0 || rbio->failb >= 0) {
2537 int dfail = 0, failp = -1;
2538
2539 if (is_data_stripe(rbio, rbio->faila))
2540 dfail++;
2541 else if (is_parity_stripe(rbio->faila))
2542 failp = rbio->faila;
2543
2544 if (is_data_stripe(rbio, rbio->failb))
2545 dfail++;
2546 else if (is_parity_stripe(rbio->failb))
2547 failp = rbio->failb;
2548
2549 /*
2550 * Because we can not use a scrubbing parity to repair
2551 * the data, so the capability of the repair is declined.
2552 * (In the case of RAID5, we can not repair anything)
2553 */
2554 if (dfail > rbio->bbio->max_errors - 1)
2555 goto cleanup;
2556
2557 /*
2558 * If all data is good, only parity is correctly, just
2559 * repair the parity.
2560 */
2561 if (dfail == 0) {
2562 finish_parity_scrub(rbio, 0);
2563 return;
2564 }
2565
2566 /*
2567 * Here means we got one corrupted data stripe and one
2568 * corrupted parity on RAID6, if the corrupted parity
2569 * is scrubbing parity, luckily, use the other one to repair
2570 * the data, or we can not repair the data stripe.
2571 */
2572 if (failp != rbio->scrubp)
2573 goto cleanup;
2574
2575 __raid_recover_end_io(rbio);
2576 } else {
2577 finish_parity_scrub(rbio, 1);
2578 }
2579 return;
2580
2581cleanup:
2582 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2583}
2584
2585/*
2586 * end io for the read phase of the rmw cycle. All the bios here are physical
2587 * stripe bios we've read from the disk so we can recalculate the parity of the
2588 * stripe.
2589 *
2590 * This will usually kick off finish_rmw once all the bios are read in, but it
2591 * may trigger parity reconstruction if we had any errors along the way
2592 */
2593static void raid56_parity_scrub_end_io(struct bio *bio)
2594{
2595 struct btrfs_raid_bio *rbio = bio->bi_private;
2596
2597 if (bio->bi_status)
2598 fail_bio_stripe(rbio, bio);
2599 else
2600 set_bio_pages_uptodate(bio);
2601
2602 bio_put(bio);
2603
2604 if (!atomic_dec_and_test(&rbio->stripes_pending))
2605 return;
2606
2607 /*
2608 * this will normally call finish_rmw to start our write
2609 * but if there are any failed stripes we'll reconstruct
2610 * from parity first
2611 */
2612 validate_rbio_for_parity_scrub(rbio);
2613}
2614
2615static void raid56_parity_scrub_stripe(struct btrfs_raid_bio *rbio)
2616{
2617 int bios_to_read = 0;
2618 struct bio_list bio_list;
2619 int ret;
2620 int pagenr;
2621 int stripe;
2622 struct bio *bio;
2623
2624 bio_list_init(&bio_list);
2625
2626 ret = alloc_rbio_essential_pages(rbio);
2627 if (ret)
2628 goto cleanup;
2629
2630 atomic_set(&rbio->error, 0);
2631 /*
2632 * build a list of bios to read all the missing parts of this
2633 * stripe
2634 */
2635 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
2636 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2637 struct page *page;
2638 /*
2639 * we want to find all the pages missing from
2640 * the rbio and read them from the disk. If
2641 * page_in_rbio finds a page in the bio list
2642 * we don't need to read it off the stripe.
2643 */
2644 page = page_in_rbio(rbio, stripe, pagenr, 1);
2645 if (page)
2646 continue;
2647
2648 page = rbio_stripe_page(rbio, stripe, pagenr);
2649 /*
2650 * the bio cache may have handed us an uptodate
2651 * page. If so, be happy and use it
2652 */
2653 if (PageUptodate(page))
2654 continue;
2655
2656 ret = rbio_add_io_page(rbio, &bio_list, page,
2657 stripe, pagenr, rbio->stripe_len);
2658 if (ret)
2659 goto cleanup;
2660 }
2661 }
2662
2663 bios_to_read = bio_list_size(&bio_list);
2664 if (!bios_to_read) {
2665 /*
2666 * this can happen if others have merged with
2667 * us, it means there is nothing left to read.
2668 * But if there are missing devices it may not be
2669 * safe to do the full stripe write yet.
2670 */
2671 goto finish;
2672 }
2673
2674 /*
2675 * the bbio may be freed once we submit the last bio. Make sure
2676 * not to touch it after that
2677 */
2678 atomic_set(&rbio->stripes_pending, bios_to_read);
2679 while (1) {
2680 bio = bio_list_pop(&bio_list);
2681 if (!bio)
2682 break;
2683
2684 bio->bi_private = rbio;
2685 bio->bi_end_io = raid56_parity_scrub_end_io;
2686 bio->bi_opf = REQ_OP_READ;
2687
2688 btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
2689
2690 submit_bio(bio);
2691 }
2692 /* the actual write will happen once the reads are done */
2693 return;
2694
2695cleanup:
2696 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2697
2698 while ((bio = bio_list_pop(&bio_list)))
2699 bio_put(bio);
2700
2701 return;
2702
2703finish:
2704 validate_rbio_for_parity_scrub(rbio);
2705}
2706
2707static void scrub_parity_work(struct btrfs_work *work)
2708{
2709 struct btrfs_raid_bio *rbio;
2710
2711 rbio = container_of(work, struct btrfs_raid_bio, work);
2712 raid56_parity_scrub_stripe(rbio);
2713}
2714
2715void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio)
2716{
2717 if (!lock_stripe_add(rbio))
2718 start_async_work(rbio, scrub_parity_work);
2719}
2720
2721/* The following code is used for dev replace of a missing RAID 5/6 device. */
2722
2723struct btrfs_raid_bio *
2724raid56_alloc_missing_rbio(struct btrfs_fs_info *fs_info, struct bio *bio,
2725 struct btrfs_bio *bbio, u64 length)
2726{
2727 struct btrfs_raid_bio *rbio;
2728
2729 rbio = alloc_rbio(fs_info, bbio, length);
2730 if (IS_ERR(rbio))
2731 return NULL;
2732
2733 rbio->operation = BTRFS_RBIO_REBUILD_MISSING;
2734 bio_list_add(&rbio->bio_list, bio);
2735 /*
2736 * This is a special bio which is used to hold the completion handler
2737 * and make the scrub rbio is similar to the other types
2738 */
2739 ASSERT(!bio->bi_iter.bi_size);
2740
2741 rbio->faila = find_logical_bio_stripe(rbio, bio);
2742 if (rbio->faila == -1) {
2743 BUG();
2744 kfree(rbio);
2745 return NULL;
2746 }
2747
2748 /*
2749 * When we get bbio, we have already increased bio_counter, record it
2750 * so we can free it at rbio_orig_end_io()
2751 */
2752 rbio->generic_bio_cnt = 1;
2753
2754 return rbio;
2755}
2756
2757void raid56_submit_missing_rbio(struct btrfs_raid_bio *rbio)
2758{
2759 if (!lock_stripe_add(rbio))
2760 start_async_work(rbio, read_rebuild_work);
2761}
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/wait.h>
9#include <linux/bio.h>
10#include <linux/slab.h>
11#include <linux/buffer_head.h>
12#include <linux/blkdev.h>
13#include <linux/random.h>
14#include <linux/iocontext.h>
15#include <linux/capability.h>
16#include <linux/ratelimit.h>
17#include <linux/kthread.h>
18#include <linux/raid/pq.h>
19#include <linux/hash.h>
20#include <linux/list_sort.h>
21#include <linux/raid/xor.h>
22#include <linux/mm.h>
23#include <asm/div64.h>
24#include "ctree.h"
25#include "extent_map.h"
26#include "disk-io.h"
27#include "transaction.h"
28#include "print-tree.h"
29#include "volumes.h"
30#include "raid56.h"
31#include "async-thread.h"
32#include "check-integrity.h"
33#include "rcu-string.h"
34
35/* set when additional merges to this rbio are not allowed */
36#define RBIO_RMW_LOCKED_BIT 1
37
38/*
39 * set when this rbio is sitting in the hash, but it is just a cache
40 * of past RMW
41 */
42#define RBIO_CACHE_BIT 2
43
44/*
45 * set when it is safe to trust the stripe_pages for caching
46 */
47#define RBIO_CACHE_READY_BIT 3
48
49#define RBIO_CACHE_SIZE 1024
50
51enum btrfs_rbio_ops {
52 BTRFS_RBIO_WRITE,
53 BTRFS_RBIO_READ_REBUILD,
54 BTRFS_RBIO_PARITY_SCRUB,
55 BTRFS_RBIO_REBUILD_MISSING,
56};
57
58struct btrfs_raid_bio {
59 struct btrfs_fs_info *fs_info;
60 struct btrfs_bio *bbio;
61
62 /* while we're doing rmw on a stripe
63 * we put it into a hash table so we can
64 * lock the stripe and merge more rbios
65 * into it.
66 */
67 struct list_head hash_list;
68
69 /*
70 * LRU list for the stripe cache
71 */
72 struct list_head stripe_cache;
73
74 /*
75 * for scheduling work in the helper threads
76 */
77 struct btrfs_work work;
78
79 /*
80 * bio list and bio_list_lock are used
81 * to add more bios into the stripe
82 * in hopes of avoiding the full rmw
83 */
84 struct bio_list bio_list;
85 spinlock_t bio_list_lock;
86
87 /* also protected by the bio_list_lock, the
88 * plug list is used by the plugging code
89 * to collect partial bios while plugged. The
90 * stripe locking code also uses it to hand off
91 * the stripe lock to the next pending IO
92 */
93 struct list_head plug_list;
94
95 /*
96 * flags that tell us if it is safe to
97 * merge with this bio
98 */
99 unsigned long flags;
100
101 /* size of each individual stripe on disk */
102 int stripe_len;
103
104 /* number of data stripes (no p/q) */
105 int nr_data;
106
107 int real_stripes;
108
109 int stripe_npages;
110 /*
111 * set if we're doing a parity rebuild
112 * for a read from higher up, which is handled
113 * differently from a parity rebuild as part of
114 * rmw
115 */
116 enum btrfs_rbio_ops operation;
117
118 /* first bad stripe */
119 int faila;
120
121 /* second bad stripe (for raid6 use) */
122 int failb;
123
124 int scrubp;
125 /*
126 * number of pages needed to represent the full
127 * stripe
128 */
129 int nr_pages;
130
131 /*
132 * size of all the bios in the bio_list. This
133 * helps us decide if the rbio maps to a full
134 * stripe or not
135 */
136 int bio_list_bytes;
137
138 int generic_bio_cnt;
139
140 refcount_t refs;
141
142 atomic_t stripes_pending;
143
144 atomic_t error;
145 /*
146 * these are two arrays of pointers. We allocate the
147 * rbio big enough to hold them both and setup their
148 * locations when the rbio is allocated
149 */
150
151 /* pointers to pages that we allocated for
152 * reading/writing stripes directly from the disk (including P/Q)
153 */
154 struct page **stripe_pages;
155
156 /*
157 * pointers to the pages in the bio_list. Stored
158 * here for faster lookup
159 */
160 struct page **bio_pages;
161
162 /*
163 * bitmap to record which horizontal stripe has data
164 */
165 unsigned long *dbitmap;
166};
167
168static int __raid56_parity_recover(struct btrfs_raid_bio *rbio);
169static noinline void finish_rmw(struct btrfs_raid_bio *rbio);
170static void rmw_work(struct btrfs_work *work);
171static void read_rebuild_work(struct btrfs_work *work);
172static void async_rmw_stripe(struct btrfs_raid_bio *rbio);
173static void async_read_rebuild(struct btrfs_raid_bio *rbio);
174static int fail_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio);
175static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed);
176static void __free_raid_bio(struct btrfs_raid_bio *rbio);
177static void index_rbio_pages(struct btrfs_raid_bio *rbio);
178static int alloc_rbio_pages(struct btrfs_raid_bio *rbio);
179
180static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
181 int need_check);
182static void async_scrub_parity(struct btrfs_raid_bio *rbio);
183
184/*
185 * the stripe hash table is used for locking, and to collect
186 * bios in hopes of making a full stripe
187 */
188int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info)
189{
190 struct btrfs_stripe_hash_table *table;
191 struct btrfs_stripe_hash_table *x;
192 struct btrfs_stripe_hash *cur;
193 struct btrfs_stripe_hash *h;
194 int num_entries = 1 << BTRFS_STRIPE_HASH_TABLE_BITS;
195 int i;
196 int table_size;
197
198 if (info->stripe_hash_table)
199 return 0;
200
201 /*
202 * The table is large, starting with order 4 and can go as high as
203 * order 7 in case lock debugging is turned on.
204 *
205 * Try harder to allocate and fallback to vmalloc to lower the chance
206 * of a failing mount.
207 */
208 table_size = sizeof(*table) + sizeof(*h) * num_entries;
209 table = kvzalloc(table_size, GFP_KERNEL);
210 if (!table)
211 return -ENOMEM;
212
213 spin_lock_init(&table->cache_lock);
214 INIT_LIST_HEAD(&table->stripe_cache);
215
216 h = table->table;
217
218 for (i = 0; i < num_entries; i++) {
219 cur = h + i;
220 INIT_LIST_HEAD(&cur->hash_list);
221 spin_lock_init(&cur->lock);
222 }
223
224 x = cmpxchg(&info->stripe_hash_table, NULL, table);
225 if (x)
226 kvfree(x);
227 return 0;
228}
229
230/*
231 * caching an rbio means to copy anything from the
232 * bio_pages array into the stripe_pages array. We
233 * use the page uptodate bit in the stripe cache array
234 * to indicate if it has valid data
235 *
236 * once the caching is done, we set the cache ready
237 * bit.
238 */
239static void cache_rbio_pages(struct btrfs_raid_bio *rbio)
240{
241 int i;
242 char *s;
243 char *d;
244 int ret;
245
246 ret = alloc_rbio_pages(rbio);
247 if (ret)
248 return;
249
250 for (i = 0; i < rbio->nr_pages; i++) {
251 if (!rbio->bio_pages[i])
252 continue;
253
254 s = kmap(rbio->bio_pages[i]);
255 d = kmap(rbio->stripe_pages[i]);
256
257 memcpy(d, s, PAGE_SIZE);
258
259 kunmap(rbio->bio_pages[i]);
260 kunmap(rbio->stripe_pages[i]);
261 SetPageUptodate(rbio->stripe_pages[i]);
262 }
263 set_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
264}
265
266/*
267 * we hash on the first logical address of the stripe
268 */
269static int rbio_bucket(struct btrfs_raid_bio *rbio)
270{
271 u64 num = rbio->bbio->raid_map[0];
272
273 /*
274 * we shift down quite a bit. We're using byte
275 * addressing, and most of the lower bits are zeros.
276 * This tends to upset hash_64, and it consistently
277 * returns just one or two different values.
278 *
279 * shifting off the lower bits fixes things.
280 */
281 return hash_64(num >> 16, BTRFS_STRIPE_HASH_TABLE_BITS);
282}
283
284/*
285 * stealing an rbio means taking all the uptodate pages from the stripe
286 * array in the source rbio and putting them into the destination rbio
287 */
288static void steal_rbio(struct btrfs_raid_bio *src, struct btrfs_raid_bio *dest)
289{
290 int i;
291 struct page *s;
292 struct page *d;
293
294 if (!test_bit(RBIO_CACHE_READY_BIT, &src->flags))
295 return;
296
297 for (i = 0; i < dest->nr_pages; i++) {
298 s = src->stripe_pages[i];
299 if (!s || !PageUptodate(s)) {
300 continue;
301 }
302
303 d = dest->stripe_pages[i];
304 if (d)
305 __free_page(d);
306
307 dest->stripe_pages[i] = s;
308 src->stripe_pages[i] = NULL;
309 }
310}
311
312/*
313 * merging means we take the bio_list from the victim and
314 * splice it into the destination. The victim should
315 * be discarded afterwards.
316 *
317 * must be called with dest->rbio_list_lock held
318 */
319static void merge_rbio(struct btrfs_raid_bio *dest,
320 struct btrfs_raid_bio *victim)
321{
322 bio_list_merge(&dest->bio_list, &victim->bio_list);
323 dest->bio_list_bytes += victim->bio_list_bytes;
324 dest->generic_bio_cnt += victim->generic_bio_cnt;
325 bio_list_init(&victim->bio_list);
326}
327
328/*
329 * used to prune items that are in the cache. The caller
330 * must hold the hash table lock.
331 */
332static void __remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
333{
334 int bucket = rbio_bucket(rbio);
335 struct btrfs_stripe_hash_table *table;
336 struct btrfs_stripe_hash *h;
337 int freeit = 0;
338
339 /*
340 * check the bit again under the hash table lock.
341 */
342 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
343 return;
344
345 table = rbio->fs_info->stripe_hash_table;
346 h = table->table + bucket;
347
348 /* hold the lock for the bucket because we may be
349 * removing it from the hash table
350 */
351 spin_lock(&h->lock);
352
353 /*
354 * hold the lock for the bio list because we need
355 * to make sure the bio list is empty
356 */
357 spin_lock(&rbio->bio_list_lock);
358
359 if (test_and_clear_bit(RBIO_CACHE_BIT, &rbio->flags)) {
360 list_del_init(&rbio->stripe_cache);
361 table->cache_size -= 1;
362 freeit = 1;
363
364 /* if the bio list isn't empty, this rbio is
365 * still involved in an IO. We take it out
366 * of the cache list, and drop the ref that
367 * was held for the list.
368 *
369 * If the bio_list was empty, we also remove
370 * the rbio from the hash_table, and drop
371 * the corresponding ref
372 */
373 if (bio_list_empty(&rbio->bio_list)) {
374 if (!list_empty(&rbio->hash_list)) {
375 list_del_init(&rbio->hash_list);
376 refcount_dec(&rbio->refs);
377 BUG_ON(!list_empty(&rbio->plug_list));
378 }
379 }
380 }
381
382 spin_unlock(&rbio->bio_list_lock);
383 spin_unlock(&h->lock);
384
385 if (freeit)
386 __free_raid_bio(rbio);
387}
388
389/*
390 * prune a given rbio from the cache
391 */
392static void remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
393{
394 struct btrfs_stripe_hash_table *table;
395 unsigned long flags;
396
397 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
398 return;
399
400 table = rbio->fs_info->stripe_hash_table;
401
402 spin_lock_irqsave(&table->cache_lock, flags);
403 __remove_rbio_from_cache(rbio);
404 spin_unlock_irqrestore(&table->cache_lock, flags);
405}
406
407/*
408 * remove everything in the cache
409 */
410static void btrfs_clear_rbio_cache(struct btrfs_fs_info *info)
411{
412 struct btrfs_stripe_hash_table *table;
413 unsigned long flags;
414 struct btrfs_raid_bio *rbio;
415
416 table = info->stripe_hash_table;
417
418 spin_lock_irqsave(&table->cache_lock, flags);
419 while (!list_empty(&table->stripe_cache)) {
420 rbio = list_entry(table->stripe_cache.next,
421 struct btrfs_raid_bio,
422 stripe_cache);
423 __remove_rbio_from_cache(rbio);
424 }
425 spin_unlock_irqrestore(&table->cache_lock, flags);
426}
427
428/*
429 * remove all cached entries and free the hash table
430 * used by unmount
431 */
432void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info)
433{
434 if (!info->stripe_hash_table)
435 return;
436 btrfs_clear_rbio_cache(info);
437 kvfree(info->stripe_hash_table);
438 info->stripe_hash_table = NULL;
439}
440
441/*
442 * insert an rbio into the stripe cache. It
443 * must have already been prepared by calling
444 * cache_rbio_pages
445 *
446 * If this rbio was already cached, it gets
447 * moved to the front of the lru.
448 *
449 * If the size of the rbio cache is too big, we
450 * prune an item.
451 */
452static void cache_rbio(struct btrfs_raid_bio *rbio)
453{
454 struct btrfs_stripe_hash_table *table;
455 unsigned long flags;
456
457 if (!test_bit(RBIO_CACHE_READY_BIT, &rbio->flags))
458 return;
459
460 table = rbio->fs_info->stripe_hash_table;
461
462 spin_lock_irqsave(&table->cache_lock, flags);
463 spin_lock(&rbio->bio_list_lock);
464
465 /* bump our ref if we were not in the list before */
466 if (!test_and_set_bit(RBIO_CACHE_BIT, &rbio->flags))
467 refcount_inc(&rbio->refs);
468
469 if (!list_empty(&rbio->stripe_cache)){
470 list_move(&rbio->stripe_cache, &table->stripe_cache);
471 } else {
472 list_add(&rbio->stripe_cache, &table->stripe_cache);
473 table->cache_size += 1;
474 }
475
476 spin_unlock(&rbio->bio_list_lock);
477
478 if (table->cache_size > RBIO_CACHE_SIZE) {
479 struct btrfs_raid_bio *found;
480
481 found = list_entry(table->stripe_cache.prev,
482 struct btrfs_raid_bio,
483 stripe_cache);
484
485 if (found != rbio)
486 __remove_rbio_from_cache(found);
487 }
488
489 spin_unlock_irqrestore(&table->cache_lock, flags);
490}
491
492/*
493 * helper function to run the xor_blocks api. It is only
494 * able to do MAX_XOR_BLOCKS at a time, so we need to
495 * loop through.
496 */
497static void run_xor(void **pages, int src_cnt, ssize_t len)
498{
499 int src_off = 0;
500 int xor_src_cnt = 0;
501 void *dest = pages[src_cnt];
502
503 while(src_cnt > 0) {
504 xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS);
505 xor_blocks(xor_src_cnt, len, dest, pages + src_off);
506
507 src_cnt -= xor_src_cnt;
508 src_off += xor_src_cnt;
509 }
510}
511
512/*
513 * returns true if the bio list inside this rbio
514 * covers an entire stripe (no rmw required).
515 * Must be called with the bio list lock held, or
516 * at a time when you know it is impossible to add
517 * new bios into the list
518 */
519static int __rbio_is_full(struct btrfs_raid_bio *rbio)
520{
521 unsigned long size = rbio->bio_list_bytes;
522 int ret = 1;
523
524 if (size != rbio->nr_data * rbio->stripe_len)
525 ret = 0;
526
527 BUG_ON(size > rbio->nr_data * rbio->stripe_len);
528 return ret;
529}
530
531static int rbio_is_full(struct btrfs_raid_bio *rbio)
532{
533 unsigned long flags;
534 int ret;
535
536 spin_lock_irqsave(&rbio->bio_list_lock, flags);
537 ret = __rbio_is_full(rbio);
538 spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
539 return ret;
540}
541
542/*
543 * returns 1 if it is safe to merge two rbios together.
544 * The merging is safe if the two rbios correspond to
545 * the same stripe and if they are both going in the same
546 * direction (read vs write), and if neither one is
547 * locked for final IO
548 *
549 * The caller is responsible for locking such that
550 * rmw_locked is safe to test
551 */
552static int rbio_can_merge(struct btrfs_raid_bio *last,
553 struct btrfs_raid_bio *cur)
554{
555 if (test_bit(RBIO_RMW_LOCKED_BIT, &last->flags) ||
556 test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags))
557 return 0;
558
559 /*
560 * we can't merge with cached rbios, since the
561 * idea is that when we merge the destination
562 * rbio is going to run our IO for us. We can
563 * steal from cached rbios though, other functions
564 * handle that.
565 */
566 if (test_bit(RBIO_CACHE_BIT, &last->flags) ||
567 test_bit(RBIO_CACHE_BIT, &cur->flags))
568 return 0;
569
570 if (last->bbio->raid_map[0] !=
571 cur->bbio->raid_map[0])
572 return 0;
573
574 /* we can't merge with different operations */
575 if (last->operation != cur->operation)
576 return 0;
577 /*
578 * We've need read the full stripe from the drive.
579 * check and repair the parity and write the new results.
580 *
581 * We're not allowed to add any new bios to the
582 * bio list here, anyone else that wants to
583 * change this stripe needs to do their own rmw.
584 */
585 if (last->operation == BTRFS_RBIO_PARITY_SCRUB)
586 return 0;
587
588 if (last->operation == BTRFS_RBIO_REBUILD_MISSING)
589 return 0;
590
591 if (last->operation == BTRFS_RBIO_READ_REBUILD) {
592 int fa = last->faila;
593 int fb = last->failb;
594 int cur_fa = cur->faila;
595 int cur_fb = cur->failb;
596
597 if (last->faila >= last->failb) {
598 fa = last->failb;
599 fb = last->faila;
600 }
601
602 if (cur->faila >= cur->failb) {
603 cur_fa = cur->failb;
604 cur_fb = cur->faila;
605 }
606
607 if (fa != cur_fa || fb != cur_fb)
608 return 0;
609 }
610 return 1;
611}
612
613static int rbio_stripe_page_index(struct btrfs_raid_bio *rbio, int stripe,
614 int index)
615{
616 return stripe * rbio->stripe_npages + index;
617}
618
619/*
620 * these are just the pages from the rbio array, not from anything
621 * the FS sent down to us
622 */
623static struct page *rbio_stripe_page(struct btrfs_raid_bio *rbio, int stripe,
624 int index)
625{
626 return rbio->stripe_pages[rbio_stripe_page_index(rbio, stripe, index)];
627}
628
629/*
630 * helper to index into the pstripe
631 */
632static struct page *rbio_pstripe_page(struct btrfs_raid_bio *rbio, int index)
633{
634 return rbio_stripe_page(rbio, rbio->nr_data, index);
635}
636
637/*
638 * helper to index into the qstripe, returns null
639 * if there is no qstripe
640 */
641static struct page *rbio_qstripe_page(struct btrfs_raid_bio *rbio, int index)
642{
643 if (rbio->nr_data + 1 == rbio->real_stripes)
644 return NULL;
645 return rbio_stripe_page(rbio, rbio->nr_data + 1, index);
646}
647
648/*
649 * The first stripe in the table for a logical address
650 * has the lock. rbios are added in one of three ways:
651 *
652 * 1) Nobody has the stripe locked yet. The rbio is given
653 * the lock and 0 is returned. The caller must start the IO
654 * themselves.
655 *
656 * 2) Someone has the stripe locked, but we're able to merge
657 * with the lock owner. The rbio is freed and the IO will
658 * start automatically along with the existing rbio. 1 is returned.
659 *
660 * 3) Someone has the stripe locked, but we're not able to merge.
661 * The rbio is added to the lock owner's plug list, or merged into
662 * an rbio already on the plug list. When the lock owner unlocks,
663 * the next rbio on the list is run and the IO is started automatically.
664 * 1 is returned
665 *
666 * If we return 0, the caller still owns the rbio and must continue with
667 * IO submission. If we return 1, the caller must assume the rbio has
668 * already been freed.
669 */
670static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
671{
672 int bucket = rbio_bucket(rbio);
673 struct btrfs_stripe_hash *h = rbio->fs_info->stripe_hash_table->table + bucket;
674 struct btrfs_raid_bio *cur;
675 struct btrfs_raid_bio *pending;
676 unsigned long flags;
677 struct btrfs_raid_bio *freeit = NULL;
678 struct btrfs_raid_bio *cache_drop = NULL;
679 int ret = 0;
680
681 spin_lock_irqsave(&h->lock, flags);
682 list_for_each_entry(cur, &h->hash_list, hash_list) {
683 if (cur->bbio->raid_map[0] == rbio->bbio->raid_map[0]) {
684 spin_lock(&cur->bio_list_lock);
685
686 /* can we steal this cached rbio's pages? */
687 if (bio_list_empty(&cur->bio_list) &&
688 list_empty(&cur->plug_list) &&
689 test_bit(RBIO_CACHE_BIT, &cur->flags) &&
690 !test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) {
691 list_del_init(&cur->hash_list);
692 refcount_dec(&cur->refs);
693
694 steal_rbio(cur, rbio);
695 cache_drop = cur;
696 spin_unlock(&cur->bio_list_lock);
697
698 goto lockit;
699 }
700
701 /* can we merge into the lock owner? */
702 if (rbio_can_merge(cur, rbio)) {
703 merge_rbio(cur, rbio);
704 spin_unlock(&cur->bio_list_lock);
705 freeit = rbio;
706 ret = 1;
707 goto out;
708 }
709
710
711 /*
712 * we couldn't merge with the running
713 * rbio, see if we can merge with the
714 * pending ones. We don't have to
715 * check for rmw_locked because there
716 * is no way they are inside finish_rmw
717 * right now
718 */
719 list_for_each_entry(pending, &cur->plug_list,
720 plug_list) {
721 if (rbio_can_merge(pending, rbio)) {
722 merge_rbio(pending, rbio);
723 spin_unlock(&cur->bio_list_lock);
724 freeit = rbio;
725 ret = 1;
726 goto out;
727 }
728 }
729
730 /* no merging, put us on the tail of the plug list,
731 * our rbio will be started with the currently
732 * running rbio unlocks
733 */
734 list_add_tail(&rbio->plug_list, &cur->plug_list);
735 spin_unlock(&cur->bio_list_lock);
736 ret = 1;
737 goto out;
738 }
739 }
740lockit:
741 refcount_inc(&rbio->refs);
742 list_add(&rbio->hash_list, &h->hash_list);
743out:
744 spin_unlock_irqrestore(&h->lock, flags);
745 if (cache_drop)
746 remove_rbio_from_cache(cache_drop);
747 if (freeit)
748 __free_raid_bio(freeit);
749 return ret;
750}
751
752/*
753 * called as rmw or parity rebuild is completed. If the plug list has more
754 * rbios waiting for this stripe, the next one on the list will be started
755 */
756static noinline void unlock_stripe(struct btrfs_raid_bio *rbio)
757{
758 int bucket;
759 struct btrfs_stripe_hash *h;
760 unsigned long flags;
761 int keep_cache = 0;
762
763 bucket = rbio_bucket(rbio);
764 h = rbio->fs_info->stripe_hash_table->table + bucket;
765
766 if (list_empty(&rbio->plug_list))
767 cache_rbio(rbio);
768
769 spin_lock_irqsave(&h->lock, flags);
770 spin_lock(&rbio->bio_list_lock);
771
772 if (!list_empty(&rbio->hash_list)) {
773 /*
774 * if we're still cached and there is no other IO
775 * to perform, just leave this rbio here for others
776 * to steal from later
777 */
778 if (list_empty(&rbio->plug_list) &&
779 test_bit(RBIO_CACHE_BIT, &rbio->flags)) {
780 keep_cache = 1;
781 clear_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
782 BUG_ON(!bio_list_empty(&rbio->bio_list));
783 goto done;
784 }
785
786 list_del_init(&rbio->hash_list);
787 refcount_dec(&rbio->refs);
788
789 /*
790 * we use the plug list to hold all the rbios
791 * waiting for the chance to lock this stripe.
792 * hand the lock over to one of them.
793 */
794 if (!list_empty(&rbio->plug_list)) {
795 struct btrfs_raid_bio *next;
796 struct list_head *head = rbio->plug_list.next;
797
798 next = list_entry(head, struct btrfs_raid_bio,
799 plug_list);
800
801 list_del_init(&rbio->plug_list);
802
803 list_add(&next->hash_list, &h->hash_list);
804 refcount_inc(&next->refs);
805 spin_unlock(&rbio->bio_list_lock);
806 spin_unlock_irqrestore(&h->lock, flags);
807
808 if (next->operation == BTRFS_RBIO_READ_REBUILD)
809 async_read_rebuild(next);
810 else if (next->operation == BTRFS_RBIO_REBUILD_MISSING) {
811 steal_rbio(rbio, next);
812 async_read_rebuild(next);
813 } else if (next->operation == BTRFS_RBIO_WRITE) {
814 steal_rbio(rbio, next);
815 async_rmw_stripe(next);
816 } else if (next->operation == BTRFS_RBIO_PARITY_SCRUB) {
817 steal_rbio(rbio, next);
818 async_scrub_parity(next);
819 }
820
821 goto done_nolock;
822 }
823 }
824done:
825 spin_unlock(&rbio->bio_list_lock);
826 spin_unlock_irqrestore(&h->lock, flags);
827
828done_nolock:
829 if (!keep_cache)
830 remove_rbio_from_cache(rbio);
831}
832
833static void __free_raid_bio(struct btrfs_raid_bio *rbio)
834{
835 int i;
836
837 if (!refcount_dec_and_test(&rbio->refs))
838 return;
839
840 WARN_ON(!list_empty(&rbio->stripe_cache));
841 WARN_ON(!list_empty(&rbio->hash_list));
842 WARN_ON(!bio_list_empty(&rbio->bio_list));
843
844 for (i = 0; i < rbio->nr_pages; i++) {
845 if (rbio->stripe_pages[i]) {
846 __free_page(rbio->stripe_pages[i]);
847 rbio->stripe_pages[i] = NULL;
848 }
849 }
850
851 btrfs_put_bbio(rbio->bbio);
852 kfree(rbio);
853}
854
855static void rbio_endio_bio_list(struct bio *cur, blk_status_t err)
856{
857 struct bio *next;
858
859 while (cur) {
860 next = cur->bi_next;
861 cur->bi_next = NULL;
862 cur->bi_status = err;
863 bio_endio(cur);
864 cur = next;
865 }
866}
867
868/*
869 * this frees the rbio and runs through all the bios in the
870 * bio_list and calls end_io on them
871 */
872static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, blk_status_t err)
873{
874 struct bio *cur = bio_list_get(&rbio->bio_list);
875 struct bio *extra;
876
877 if (rbio->generic_bio_cnt)
878 btrfs_bio_counter_sub(rbio->fs_info, rbio->generic_bio_cnt);
879
880 /*
881 * At this moment, rbio->bio_list is empty, however since rbio does not
882 * always have RBIO_RMW_LOCKED_BIT set and rbio is still linked on the
883 * hash list, rbio may be merged with others so that rbio->bio_list
884 * becomes non-empty.
885 * Once unlock_stripe() is done, rbio->bio_list will not be updated any
886 * more and we can call bio_endio() on all queued bios.
887 */
888 unlock_stripe(rbio);
889 extra = bio_list_get(&rbio->bio_list);
890 __free_raid_bio(rbio);
891
892 rbio_endio_bio_list(cur, err);
893 if (extra)
894 rbio_endio_bio_list(extra, err);
895}
896
897/*
898 * end io function used by finish_rmw. When we finally
899 * get here, we've written a full stripe
900 */
901static void raid_write_end_io(struct bio *bio)
902{
903 struct btrfs_raid_bio *rbio = bio->bi_private;
904 blk_status_t err = bio->bi_status;
905 int max_errors;
906
907 if (err)
908 fail_bio_stripe(rbio, bio);
909
910 bio_put(bio);
911
912 if (!atomic_dec_and_test(&rbio->stripes_pending))
913 return;
914
915 err = BLK_STS_OK;
916
917 /* OK, we have read all the stripes we need to. */
918 max_errors = (rbio->operation == BTRFS_RBIO_PARITY_SCRUB) ?
919 0 : rbio->bbio->max_errors;
920 if (atomic_read(&rbio->error) > max_errors)
921 err = BLK_STS_IOERR;
922
923 rbio_orig_end_io(rbio, err);
924}
925
926/*
927 * the read/modify/write code wants to use the original bio for
928 * any pages it included, and then use the rbio for everything
929 * else. This function decides if a given index (stripe number)
930 * and page number in that stripe fall inside the original bio
931 * or the rbio.
932 *
933 * if you set bio_list_only, you'll get a NULL back for any ranges
934 * that are outside the bio_list
935 *
936 * This doesn't take any refs on anything, you get a bare page pointer
937 * and the caller must bump refs as required.
938 *
939 * You must call index_rbio_pages once before you can trust
940 * the answers from this function.
941 */
942static struct page *page_in_rbio(struct btrfs_raid_bio *rbio,
943 int index, int pagenr, int bio_list_only)
944{
945 int chunk_page;
946 struct page *p = NULL;
947
948 chunk_page = index * (rbio->stripe_len >> PAGE_SHIFT) + pagenr;
949
950 spin_lock_irq(&rbio->bio_list_lock);
951 p = rbio->bio_pages[chunk_page];
952 spin_unlock_irq(&rbio->bio_list_lock);
953
954 if (p || bio_list_only)
955 return p;
956
957 return rbio->stripe_pages[chunk_page];
958}
959
960/*
961 * number of pages we need for the entire stripe across all the
962 * drives
963 */
964static unsigned long rbio_nr_pages(unsigned long stripe_len, int nr_stripes)
965{
966 return DIV_ROUND_UP(stripe_len, PAGE_SIZE) * nr_stripes;
967}
968
969/*
970 * allocation and initial setup for the btrfs_raid_bio. Not
971 * this does not allocate any pages for rbio->pages.
972 */
973static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info,
974 struct btrfs_bio *bbio,
975 u64 stripe_len)
976{
977 struct btrfs_raid_bio *rbio;
978 int nr_data = 0;
979 int real_stripes = bbio->num_stripes - bbio->num_tgtdevs;
980 int num_pages = rbio_nr_pages(stripe_len, real_stripes);
981 int stripe_npages = DIV_ROUND_UP(stripe_len, PAGE_SIZE);
982 void *p;
983
984 rbio = kzalloc(sizeof(*rbio) + num_pages * sizeof(struct page *) * 2 +
985 DIV_ROUND_UP(stripe_npages, BITS_PER_LONG) *
986 sizeof(long), GFP_NOFS);
987 if (!rbio)
988 return ERR_PTR(-ENOMEM);
989
990 bio_list_init(&rbio->bio_list);
991 INIT_LIST_HEAD(&rbio->plug_list);
992 spin_lock_init(&rbio->bio_list_lock);
993 INIT_LIST_HEAD(&rbio->stripe_cache);
994 INIT_LIST_HEAD(&rbio->hash_list);
995 rbio->bbio = bbio;
996 rbio->fs_info = fs_info;
997 rbio->stripe_len = stripe_len;
998 rbio->nr_pages = num_pages;
999 rbio->real_stripes = real_stripes;
1000 rbio->stripe_npages = stripe_npages;
1001 rbio->faila = -1;
1002 rbio->failb = -1;
1003 refcount_set(&rbio->refs, 1);
1004 atomic_set(&rbio->error, 0);
1005 atomic_set(&rbio->stripes_pending, 0);
1006
1007 /*
1008 * the stripe_pages and bio_pages array point to the extra
1009 * memory we allocated past the end of the rbio
1010 */
1011 p = rbio + 1;
1012 rbio->stripe_pages = p;
1013 rbio->bio_pages = p + sizeof(struct page *) * num_pages;
1014 rbio->dbitmap = p + sizeof(struct page *) * num_pages * 2;
1015
1016 if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID5)
1017 nr_data = real_stripes - 1;
1018 else if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID6)
1019 nr_data = real_stripes - 2;
1020 else
1021 BUG();
1022
1023 rbio->nr_data = nr_data;
1024 return rbio;
1025}
1026
1027/* allocate pages for all the stripes in the bio, including parity */
1028static int alloc_rbio_pages(struct btrfs_raid_bio *rbio)
1029{
1030 int i;
1031 struct page *page;
1032
1033 for (i = 0; i < rbio->nr_pages; i++) {
1034 if (rbio->stripe_pages[i])
1035 continue;
1036 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1037 if (!page)
1038 return -ENOMEM;
1039 rbio->stripe_pages[i] = page;
1040 }
1041 return 0;
1042}
1043
1044/* only allocate pages for p/q stripes */
1045static int alloc_rbio_parity_pages(struct btrfs_raid_bio *rbio)
1046{
1047 int i;
1048 struct page *page;
1049
1050 i = rbio_stripe_page_index(rbio, rbio->nr_data, 0);
1051
1052 for (; i < rbio->nr_pages; i++) {
1053 if (rbio->stripe_pages[i])
1054 continue;
1055 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1056 if (!page)
1057 return -ENOMEM;
1058 rbio->stripe_pages[i] = page;
1059 }
1060 return 0;
1061}
1062
1063/*
1064 * add a single page from a specific stripe into our list of bios for IO
1065 * this will try to merge into existing bios if possible, and returns
1066 * zero if all went well.
1067 */
1068static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
1069 struct bio_list *bio_list,
1070 struct page *page,
1071 int stripe_nr,
1072 unsigned long page_index,
1073 unsigned long bio_max_len)
1074{
1075 struct bio *last = bio_list->tail;
1076 u64 last_end = 0;
1077 int ret;
1078 struct bio *bio;
1079 struct btrfs_bio_stripe *stripe;
1080 u64 disk_start;
1081
1082 stripe = &rbio->bbio->stripes[stripe_nr];
1083 disk_start = stripe->physical + (page_index << PAGE_SHIFT);
1084
1085 /* if the device is missing, just fail this stripe */
1086 if (!stripe->dev->bdev)
1087 return fail_rbio_index(rbio, stripe_nr);
1088
1089 /* see if we can add this page onto our existing bio */
1090 if (last) {
1091 last_end = (u64)last->bi_iter.bi_sector << 9;
1092 last_end += last->bi_iter.bi_size;
1093
1094 /*
1095 * we can't merge these if they are from different
1096 * devices or if they are not contiguous
1097 */
1098 if (last_end == disk_start && stripe->dev->bdev &&
1099 !last->bi_status &&
1100 last->bi_disk == stripe->dev->bdev->bd_disk &&
1101 last->bi_partno == stripe->dev->bdev->bd_partno) {
1102 ret = bio_add_page(last, page, PAGE_SIZE, 0);
1103 if (ret == PAGE_SIZE)
1104 return 0;
1105 }
1106 }
1107
1108 /* put a new bio on the list */
1109 bio = btrfs_io_bio_alloc(bio_max_len >> PAGE_SHIFT ?: 1);
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 = (u64)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->real_stripes];
1184 int nr_data = rbio->nr_data;
1185 int stripe;
1186 int pagenr;
1187 int p_stripe = -1;
1188 int q_stripe = -1;
1189 struct bio_list bio_list;
1190 struct bio *bio;
1191 int ret;
1192
1193 bio_list_init(&bio_list);
1194
1195 if (rbio->real_stripes - rbio->nr_data == 1) {
1196 p_stripe = rbio->real_stripes - 1;
1197 } else if (rbio->real_stripes - rbio->nr_data == 2) {
1198 p_stripe = rbio->real_stripes - 2;
1199 q_stripe = rbio->real_stripes - 1;
1200 } else {
1201 BUG();
1202 }
1203
1204 /* at this point we either have a full stripe,
1205 * or we've read the full stripe from the drive.
1206 * recalculate the parity and write the new results.
1207 *
1208 * We're not allowed to add any new bios to the
1209 * bio list here, anyone else that wants to
1210 * change this stripe needs to do their own rmw.
1211 */
1212 spin_lock_irq(&rbio->bio_list_lock);
1213 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1214 spin_unlock_irq(&rbio->bio_list_lock);
1215
1216 atomic_set(&rbio->error, 0);
1217
1218 /*
1219 * now that we've set rmw_locked, run through the
1220 * bio list one last time and map the page pointers
1221 *
1222 * We don't cache full rbios because we're assuming
1223 * the higher layers are unlikely to use this area of
1224 * the disk again soon. If they do use it again,
1225 * hopefully they will send another full bio.
1226 */
1227 index_rbio_pages(rbio);
1228 if (!rbio_is_full(rbio))
1229 cache_rbio_pages(rbio);
1230 else
1231 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
1232
1233 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1234 struct page *p;
1235 /* first collect one page from each data stripe */
1236 for (stripe = 0; stripe < nr_data; stripe++) {
1237 p = page_in_rbio(rbio, stripe, pagenr, 0);
1238 pointers[stripe] = kmap(p);
1239 }
1240
1241 /* then add the parity stripe */
1242 p = rbio_pstripe_page(rbio, pagenr);
1243 SetPageUptodate(p);
1244 pointers[stripe++] = kmap(p);
1245
1246 if (q_stripe != -1) {
1247
1248 /*
1249 * raid6, add the qstripe and call the
1250 * library function to fill in our p/q
1251 */
1252 p = rbio_qstripe_page(rbio, pagenr);
1253 SetPageUptodate(p);
1254 pointers[stripe++] = kmap(p);
1255
1256 raid6_call.gen_syndrome(rbio->real_stripes, PAGE_SIZE,
1257 pointers);
1258 } else {
1259 /* raid5 */
1260 memcpy(pointers[nr_data], pointers[0], PAGE_SIZE);
1261 run_xor(pointers + 1, nr_data - 1, PAGE_SIZE);
1262 }
1263
1264
1265 for (stripe = 0; stripe < rbio->real_stripes; stripe++)
1266 kunmap(page_in_rbio(rbio, stripe, pagenr, 0));
1267 }
1268
1269 /*
1270 * time to start writing. Make bios for everything from the
1271 * higher layers (the bio_list in our rbio) and our p/q. Ignore
1272 * everything else.
1273 */
1274 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1275 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1276 struct page *page;
1277 if (stripe < rbio->nr_data) {
1278 page = page_in_rbio(rbio, stripe, pagenr, 1);
1279 if (!page)
1280 continue;
1281 } else {
1282 page = rbio_stripe_page(rbio, stripe, pagenr);
1283 }
1284
1285 ret = rbio_add_io_page(rbio, &bio_list,
1286 page, stripe, pagenr, rbio->stripe_len);
1287 if (ret)
1288 goto cleanup;
1289 }
1290 }
1291
1292 if (likely(!bbio->num_tgtdevs))
1293 goto write_data;
1294
1295 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1296 if (!bbio->tgtdev_map[stripe])
1297 continue;
1298
1299 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1300 struct page *page;
1301 if (stripe < rbio->nr_data) {
1302 page = page_in_rbio(rbio, stripe, pagenr, 1);
1303 if (!page)
1304 continue;
1305 } else {
1306 page = rbio_stripe_page(rbio, stripe, pagenr);
1307 }
1308
1309 ret = rbio_add_io_page(rbio, &bio_list, page,
1310 rbio->bbio->tgtdev_map[stripe],
1311 pagenr, rbio->stripe_len);
1312 if (ret)
1313 goto cleanup;
1314 }
1315 }
1316
1317write_data:
1318 atomic_set(&rbio->stripes_pending, bio_list_size(&bio_list));
1319 BUG_ON(atomic_read(&rbio->stripes_pending) == 0);
1320
1321 while (1) {
1322 bio = bio_list_pop(&bio_list);
1323 if (!bio)
1324 break;
1325
1326 bio->bi_private = rbio;
1327 bio->bi_end_io = raid_write_end_io;
1328 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
1329
1330 submit_bio(bio);
1331 }
1332 return;
1333
1334cleanup:
1335 rbio_orig_end_io(rbio, BLK_STS_IOERR);
1336
1337 while ((bio = bio_list_pop(&bio_list)))
1338 bio_put(bio);
1339}
1340
1341/*
1342 * helper to find the stripe number for a given bio. Used to figure out which
1343 * stripe has failed. This expects the bio to correspond to a physical disk,
1344 * so it looks up based on physical sector numbers.
1345 */
1346static int find_bio_stripe(struct btrfs_raid_bio *rbio,
1347 struct bio *bio)
1348{
1349 u64 physical = bio->bi_iter.bi_sector;
1350 u64 stripe_start;
1351 int i;
1352 struct btrfs_bio_stripe *stripe;
1353
1354 physical <<= 9;
1355
1356 for (i = 0; i < rbio->bbio->num_stripes; i++) {
1357 stripe = &rbio->bbio->stripes[i];
1358 stripe_start = stripe->physical;
1359 if (physical >= stripe_start &&
1360 physical < stripe_start + rbio->stripe_len &&
1361 stripe->dev->bdev &&
1362 bio->bi_disk == stripe->dev->bdev->bd_disk &&
1363 bio->bi_partno == stripe->dev->bdev->bd_partno) {
1364 return i;
1365 }
1366 }
1367 return -1;
1368}
1369
1370/*
1371 * helper to find the stripe number for a given
1372 * bio (before mapping). Used to figure out which stripe has
1373 * failed. This looks up based on logical block numbers.
1374 */
1375static int find_logical_bio_stripe(struct btrfs_raid_bio *rbio,
1376 struct bio *bio)
1377{
1378 u64 logical = bio->bi_iter.bi_sector;
1379 u64 stripe_start;
1380 int i;
1381
1382 logical <<= 9;
1383
1384 for (i = 0; i < rbio->nr_data; i++) {
1385 stripe_start = rbio->bbio->raid_map[i];
1386 if (logical >= stripe_start &&
1387 logical < stripe_start + rbio->stripe_len) {
1388 return i;
1389 }
1390 }
1391 return -1;
1392}
1393
1394/*
1395 * returns -EIO if we had too many failures
1396 */
1397static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed)
1398{
1399 unsigned long flags;
1400 int ret = 0;
1401
1402 spin_lock_irqsave(&rbio->bio_list_lock, flags);
1403
1404 /* we already know this stripe is bad, move on */
1405 if (rbio->faila == failed || rbio->failb == failed)
1406 goto out;
1407
1408 if (rbio->faila == -1) {
1409 /* first failure on this rbio */
1410 rbio->faila = failed;
1411 atomic_inc(&rbio->error);
1412 } else if (rbio->failb == -1) {
1413 /* second failure on this rbio */
1414 rbio->failb = failed;
1415 atomic_inc(&rbio->error);
1416 } else {
1417 ret = -EIO;
1418 }
1419out:
1420 spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
1421
1422 return ret;
1423}
1424
1425/*
1426 * helper to fail a stripe based on a physical disk
1427 * bio.
1428 */
1429static int fail_bio_stripe(struct btrfs_raid_bio *rbio,
1430 struct bio *bio)
1431{
1432 int failed = find_bio_stripe(rbio, bio);
1433
1434 if (failed < 0)
1435 return -EIO;
1436
1437 return fail_rbio_index(rbio, failed);
1438}
1439
1440/*
1441 * this sets each page in the bio uptodate. It should only be used on private
1442 * rbio pages, nothing that comes in from the higher layers
1443 */
1444static void set_bio_pages_uptodate(struct bio *bio)
1445{
1446 struct bio_vec *bvec;
1447 int i;
1448
1449 ASSERT(!bio_flagged(bio, BIO_CLONED));
1450
1451 bio_for_each_segment_all(bvec, bio, i)
1452 SetPageUptodate(bvec->bv_page);
1453}
1454
1455/*
1456 * end io for the read phase of the rmw cycle. All the bios here are physical
1457 * stripe bios we've read from the disk so we can recalculate the parity of the
1458 * stripe.
1459 *
1460 * This will usually kick off finish_rmw once all the bios are read in, but it
1461 * may trigger parity reconstruction if we had any errors along the way
1462 */
1463static void raid_rmw_end_io(struct bio *bio)
1464{
1465 struct btrfs_raid_bio *rbio = bio->bi_private;
1466
1467 if (bio->bi_status)
1468 fail_bio_stripe(rbio, bio);
1469 else
1470 set_bio_pages_uptodate(bio);
1471
1472 bio_put(bio);
1473
1474 if (!atomic_dec_and_test(&rbio->stripes_pending))
1475 return;
1476
1477 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
1478 goto cleanup;
1479
1480 /*
1481 * this will normally call finish_rmw to start our write
1482 * but if there are any failed stripes we'll reconstruct
1483 * from parity first
1484 */
1485 validate_rbio_for_rmw(rbio);
1486 return;
1487
1488cleanup:
1489
1490 rbio_orig_end_io(rbio, BLK_STS_IOERR);
1491}
1492
1493static void async_rmw_stripe(struct btrfs_raid_bio *rbio)
1494{
1495 btrfs_init_work(&rbio->work, btrfs_rmw_helper, rmw_work, NULL, NULL);
1496 btrfs_queue_work(rbio->fs_info->rmw_workers, &rbio->work);
1497}
1498
1499static void async_read_rebuild(struct btrfs_raid_bio *rbio)
1500{
1501 btrfs_init_work(&rbio->work, btrfs_rmw_helper,
1502 read_rebuild_work, NULL, NULL);
1503
1504 btrfs_queue_work(rbio->fs_info->rmw_workers, &rbio->work);
1505}
1506
1507/*
1508 * the stripe must be locked by the caller. It will
1509 * unlock after all the writes are done
1510 */
1511static int raid56_rmw_stripe(struct btrfs_raid_bio *rbio)
1512{
1513 int bios_to_read = 0;
1514 struct bio_list bio_list;
1515 int ret;
1516 int pagenr;
1517 int stripe;
1518 struct bio *bio;
1519
1520 bio_list_init(&bio_list);
1521
1522 ret = alloc_rbio_pages(rbio);
1523 if (ret)
1524 goto cleanup;
1525
1526 index_rbio_pages(rbio);
1527
1528 atomic_set(&rbio->error, 0);
1529 /*
1530 * build a list of bios to read all the missing parts of this
1531 * stripe
1532 */
1533 for (stripe = 0; stripe < rbio->nr_data; stripe++) {
1534 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1535 struct page *page;
1536 /*
1537 * we want to find all the pages missing from
1538 * the rbio and read them from the disk. If
1539 * page_in_rbio finds a page in the bio list
1540 * we don't need to read it off the stripe.
1541 */
1542 page = page_in_rbio(rbio, stripe, pagenr, 1);
1543 if (page)
1544 continue;
1545
1546 page = rbio_stripe_page(rbio, stripe, pagenr);
1547 /*
1548 * the bio cache may have handed us an uptodate
1549 * page. If so, be happy and use it
1550 */
1551 if (PageUptodate(page))
1552 continue;
1553
1554 ret = rbio_add_io_page(rbio, &bio_list, page,
1555 stripe, pagenr, rbio->stripe_len);
1556 if (ret)
1557 goto cleanup;
1558 }
1559 }
1560
1561 bios_to_read = bio_list_size(&bio_list);
1562 if (!bios_to_read) {
1563 /*
1564 * this can happen if others have merged with
1565 * us, it means there is nothing left to read.
1566 * But if there are missing devices it may not be
1567 * safe to do the full stripe write yet.
1568 */
1569 goto finish;
1570 }
1571
1572 /*
1573 * the bbio may be freed once we submit the last bio. Make sure
1574 * not to touch it after that
1575 */
1576 atomic_set(&rbio->stripes_pending, bios_to_read);
1577 while (1) {
1578 bio = bio_list_pop(&bio_list);
1579 if (!bio)
1580 break;
1581
1582 bio->bi_private = rbio;
1583 bio->bi_end_io = raid_rmw_end_io;
1584 bio_set_op_attrs(bio, REQ_OP_READ, 0);
1585
1586 btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
1587
1588 submit_bio(bio);
1589 }
1590 /* the actual write will happen once the reads are done */
1591 return 0;
1592
1593cleanup:
1594 rbio_orig_end_io(rbio, BLK_STS_IOERR);
1595
1596 while ((bio = bio_list_pop(&bio_list)))
1597 bio_put(bio);
1598
1599 return -EIO;
1600
1601finish:
1602 validate_rbio_for_rmw(rbio);
1603 return 0;
1604}
1605
1606/*
1607 * if the upper layers pass in a full stripe, we thank them by only allocating
1608 * enough pages to hold the parity, and sending it all down quickly.
1609 */
1610static int full_stripe_write(struct btrfs_raid_bio *rbio)
1611{
1612 int ret;
1613
1614 ret = alloc_rbio_parity_pages(rbio);
1615 if (ret) {
1616 __free_raid_bio(rbio);
1617 return ret;
1618 }
1619
1620 ret = lock_stripe_add(rbio);
1621 if (ret == 0)
1622 finish_rmw(rbio);
1623 return 0;
1624}
1625
1626/*
1627 * partial stripe writes get handed over to async helpers.
1628 * We're really hoping to merge a few more writes into this
1629 * rbio before calculating new parity
1630 */
1631static int partial_stripe_write(struct btrfs_raid_bio *rbio)
1632{
1633 int ret;
1634
1635 ret = lock_stripe_add(rbio);
1636 if (ret == 0)
1637 async_rmw_stripe(rbio);
1638 return 0;
1639}
1640
1641/*
1642 * sometimes while we were reading from the drive to
1643 * recalculate parity, enough new bios come into create
1644 * a full stripe. So we do a check here to see if we can
1645 * go directly to finish_rmw
1646 */
1647static int __raid56_parity_write(struct btrfs_raid_bio *rbio)
1648{
1649 /* head off into rmw land if we don't have a full stripe */
1650 if (!rbio_is_full(rbio))
1651 return partial_stripe_write(rbio);
1652 return full_stripe_write(rbio);
1653}
1654
1655/*
1656 * We use plugging call backs to collect full stripes.
1657 * Any time we get a partial stripe write while plugged
1658 * we collect it into a list. When the unplug comes down,
1659 * we sort the list by logical block number and merge
1660 * everything we can into the same rbios
1661 */
1662struct btrfs_plug_cb {
1663 struct blk_plug_cb cb;
1664 struct btrfs_fs_info *info;
1665 struct list_head rbio_list;
1666 struct btrfs_work work;
1667};
1668
1669/*
1670 * rbios on the plug list are sorted for easier merging.
1671 */
1672static int plug_cmp(void *priv, struct list_head *a, struct list_head *b)
1673{
1674 struct btrfs_raid_bio *ra = container_of(a, struct btrfs_raid_bio,
1675 plug_list);
1676 struct btrfs_raid_bio *rb = container_of(b, struct btrfs_raid_bio,
1677 plug_list);
1678 u64 a_sector = ra->bio_list.head->bi_iter.bi_sector;
1679 u64 b_sector = rb->bio_list.head->bi_iter.bi_sector;
1680
1681 if (a_sector < b_sector)
1682 return -1;
1683 if (a_sector > b_sector)
1684 return 1;
1685 return 0;
1686}
1687
1688static void run_plug(struct btrfs_plug_cb *plug)
1689{
1690 struct btrfs_raid_bio *cur;
1691 struct btrfs_raid_bio *last = NULL;
1692
1693 /*
1694 * sort our plug list then try to merge
1695 * everything we can in hopes of creating full
1696 * stripes.
1697 */
1698 list_sort(NULL, &plug->rbio_list, plug_cmp);
1699 while (!list_empty(&plug->rbio_list)) {
1700 cur = list_entry(plug->rbio_list.next,
1701 struct btrfs_raid_bio, plug_list);
1702 list_del_init(&cur->plug_list);
1703
1704 if (rbio_is_full(cur)) {
1705 /* we have a full stripe, send it down */
1706 full_stripe_write(cur);
1707 continue;
1708 }
1709 if (last) {
1710 if (rbio_can_merge(last, cur)) {
1711 merge_rbio(last, cur);
1712 __free_raid_bio(cur);
1713 continue;
1714
1715 }
1716 __raid56_parity_write(last);
1717 }
1718 last = cur;
1719 }
1720 if (last) {
1721 __raid56_parity_write(last);
1722 }
1723 kfree(plug);
1724}
1725
1726/*
1727 * if the unplug comes from schedule, we have to push the
1728 * work off to a helper thread
1729 */
1730static void unplug_work(struct btrfs_work *work)
1731{
1732 struct btrfs_plug_cb *plug;
1733 plug = container_of(work, struct btrfs_plug_cb, work);
1734 run_plug(plug);
1735}
1736
1737static void btrfs_raid_unplug(struct blk_plug_cb *cb, bool from_schedule)
1738{
1739 struct btrfs_plug_cb *plug;
1740 plug = container_of(cb, struct btrfs_plug_cb, cb);
1741
1742 if (from_schedule) {
1743 btrfs_init_work(&plug->work, btrfs_rmw_helper,
1744 unplug_work, NULL, NULL);
1745 btrfs_queue_work(plug->info->rmw_workers,
1746 &plug->work);
1747 return;
1748 }
1749 run_plug(plug);
1750}
1751
1752/*
1753 * our main entry point for writes from the rest of the FS.
1754 */
1755int raid56_parity_write(struct btrfs_fs_info *fs_info, struct bio *bio,
1756 struct btrfs_bio *bbio, u64 stripe_len)
1757{
1758 struct btrfs_raid_bio *rbio;
1759 struct btrfs_plug_cb *plug = NULL;
1760 struct blk_plug_cb *cb;
1761 int ret;
1762
1763 rbio = alloc_rbio(fs_info, bbio, stripe_len);
1764 if (IS_ERR(rbio)) {
1765 btrfs_put_bbio(bbio);
1766 return PTR_ERR(rbio);
1767 }
1768 bio_list_add(&rbio->bio_list, bio);
1769 rbio->bio_list_bytes = bio->bi_iter.bi_size;
1770 rbio->operation = BTRFS_RBIO_WRITE;
1771
1772 btrfs_bio_counter_inc_noblocked(fs_info);
1773 rbio->generic_bio_cnt = 1;
1774
1775 /*
1776 * don't plug on full rbios, just get them out the door
1777 * as quickly as we can
1778 */
1779 if (rbio_is_full(rbio)) {
1780 ret = full_stripe_write(rbio);
1781 if (ret)
1782 btrfs_bio_counter_dec(fs_info);
1783 return ret;
1784 }
1785
1786 cb = blk_check_plugged(btrfs_raid_unplug, fs_info, sizeof(*plug));
1787 if (cb) {
1788 plug = container_of(cb, struct btrfs_plug_cb, cb);
1789 if (!plug->info) {
1790 plug->info = fs_info;
1791 INIT_LIST_HEAD(&plug->rbio_list);
1792 }
1793 list_add_tail(&rbio->plug_list, &plug->rbio_list);
1794 ret = 0;
1795 } else {
1796 ret = __raid56_parity_write(rbio);
1797 if (ret)
1798 btrfs_bio_counter_dec(fs_info);
1799 }
1800 return ret;
1801}
1802
1803/*
1804 * all parity reconstruction happens here. We've read in everything
1805 * we can find from the drives and this does the heavy lifting of
1806 * sorting the good from the bad.
1807 */
1808static void __raid_recover_end_io(struct btrfs_raid_bio *rbio)
1809{
1810 int pagenr, stripe;
1811 void **pointers;
1812 int faila = -1, failb = -1;
1813 struct page *page;
1814 blk_status_t err;
1815 int i;
1816
1817 pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
1818 if (!pointers) {
1819 err = BLK_STS_RESOURCE;
1820 goto cleanup_io;
1821 }
1822
1823 faila = rbio->faila;
1824 failb = rbio->failb;
1825
1826 if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1827 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) {
1828 spin_lock_irq(&rbio->bio_list_lock);
1829 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1830 spin_unlock_irq(&rbio->bio_list_lock);
1831 }
1832
1833 index_rbio_pages(rbio);
1834
1835 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1836 /*
1837 * Now we just use bitmap to mark the horizontal stripes in
1838 * which we have data when doing parity scrub.
1839 */
1840 if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB &&
1841 !test_bit(pagenr, rbio->dbitmap))
1842 continue;
1843
1844 /* setup our array of pointers with pages
1845 * from each stripe
1846 */
1847 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1848 /*
1849 * if we're rebuilding a read, we have to use
1850 * pages from the bio list
1851 */
1852 if ((rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1853 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) &&
1854 (stripe == faila || stripe == failb)) {
1855 page = page_in_rbio(rbio, stripe, pagenr, 0);
1856 } else {
1857 page = rbio_stripe_page(rbio, stripe, pagenr);
1858 }
1859 pointers[stripe] = kmap(page);
1860 }
1861
1862 /* all raid6 handling here */
1863 if (rbio->bbio->map_type & BTRFS_BLOCK_GROUP_RAID6) {
1864 /*
1865 * single failure, rebuild from parity raid5
1866 * style
1867 */
1868 if (failb < 0) {
1869 if (faila == rbio->nr_data) {
1870 /*
1871 * Just the P stripe has failed, without
1872 * a bad data or Q stripe.
1873 * TODO, we should redo the xor here.
1874 */
1875 err = BLK_STS_IOERR;
1876 goto cleanup;
1877 }
1878 /*
1879 * a single failure in raid6 is rebuilt
1880 * in the pstripe code below
1881 */
1882 goto pstripe;
1883 }
1884
1885 /* make sure our ps and qs are in order */
1886 if (faila > failb) {
1887 int tmp = failb;
1888 failb = faila;
1889 faila = tmp;
1890 }
1891
1892 /* if the q stripe is failed, do a pstripe reconstruction
1893 * from the xors.
1894 * If both the q stripe and the P stripe are failed, we're
1895 * here due to a crc mismatch and we can't give them the
1896 * data they want
1897 */
1898 if (rbio->bbio->raid_map[failb] == RAID6_Q_STRIPE) {
1899 if (rbio->bbio->raid_map[faila] ==
1900 RAID5_P_STRIPE) {
1901 err = BLK_STS_IOERR;
1902 goto cleanup;
1903 }
1904 /*
1905 * otherwise we have one bad data stripe and
1906 * a good P stripe. raid5!
1907 */
1908 goto pstripe;
1909 }
1910
1911 if (rbio->bbio->raid_map[failb] == RAID5_P_STRIPE) {
1912 raid6_datap_recov(rbio->real_stripes,
1913 PAGE_SIZE, faila, pointers);
1914 } else {
1915 raid6_2data_recov(rbio->real_stripes,
1916 PAGE_SIZE, faila, failb,
1917 pointers);
1918 }
1919 } else {
1920 void *p;
1921
1922 /* rebuild from P stripe here (raid5 or raid6) */
1923 BUG_ON(failb != -1);
1924pstripe:
1925 /* Copy parity block into failed block to start with */
1926 memcpy(pointers[faila],
1927 pointers[rbio->nr_data],
1928 PAGE_SIZE);
1929
1930 /* rearrange the pointer array */
1931 p = pointers[faila];
1932 for (stripe = faila; stripe < rbio->nr_data - 1; stripe++)
1933 pointers[stripe] = pointers[stripe + 1];
1934 pointers[rbio->nr_data - 1] = p;
1935
1936 /* xor in the rest */
1937 run_xor(pointers, rbio->nr_data - 1, PAGE_SIZE);
1938 }
1939 /* if we're doing this rebuild as part of an rmw, go through
1940 * and set all of our private rbio pages in the
1941 * failed stripes as uptodate. This way finish_rmw will
1942 * know they can be trusted. If this was a read reconstruction,
1943 * other endio functions will fiddle the uptodate bits
1944 */
1945 if (rbio->operation == BTRFS_RBIO_WRITE) {
1946 for (i = 0; i < rbio->stripe_npages; i++) {
1947 if (faila != -1) {
1948 page = rbio_stripe_page(rbio, faila, i);
1949 SetPageUptodate(page);
1950 }
1951 if (failb != -1) {
1952 page = rbio_stripe_page(rbio, failb, i);
1953 SetPageUptodate(page);
1954 }
1955 }
1956 }
1957 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1958 /*
1959 * if we're rebuilding a read, we have to use
1960 * pages from the bio list
1961 */
1962 if ((rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1963 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) &&
1964 (stripe == faila || stripe == failb)) {
1965 page = page_in_rbio(rbio, stripe, pagenr, 0);
1966 } else {
1967 page = rbio_stripe_page(rbio, stripe, pagenr);
1968 }
1969 kunmap(page);
1970 }
1971 }
1972
1973 err = BLK_STS_OK;
1974cleanup:
1975 kfree(pointers);
1976
1977cleanup_io:
1978 /*
1979 * Similar to READ_REBUILD, REBUILD_MISSING at this point also has a
1980 * valid rbio which is consistent with ondisk content, thus such a
1981 * valid rbio can be cached to avoid further disk reads.
1982 */
1983 if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1984 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) {
1985 /*
1986 * - In case of two failures, where rbio->failb != -1:
1987 *
1988 * Do not cache this rbio since the above read reconstruction
1989 * (raid6_datap_recov() or raid6_2data_recov()) may have
1990 * changed some content of stripes which are not identical to
1991 * on-disk content any more, otherwise, a later write/recover
1992 * may steal stripe_pages from this rbio and end up with
1993 * corruptions or rebuild failures.
1994 *
1995 * - In case of single failure, where rbio->failb == -1:
1996 *
1997 * Cache this rbio iff the above read reconstruction is
1998 * excuted without problems.
1999 */
2000 if (err == BLK_STS_OK && rbio->failb < 0)
2001 cache_rbio_pages(rbio);
2002 else
2003 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
2004
2005 rbio_orig_end_io(rbio, err);
2006 } else if (err == BLK_STS_OK) {
2007 rbio->faila = -1;
2008 rbio->failb = -1;
2009
2010 if (rbio->operation == BTRFS_RBIO_WRITE)
2011 finish_rmw(rbio);
2012 else if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB)
2013 finish_parity_scrub(rbio, 0);
2014 else
2015 BUG();
2016 } else {
2017 rbio_orig_end_io(rbio, err);
2018 }
2019}
2020
2021/*
2022 * This is called only for stripes we've read from disk to
2023 * reconstruct the parity.
2024 */
2025static void raid_recover_end_io(struct bio *bio)
2026{
2027 struct btrfs_raid_bio *rbio = bio->bi_private;
2028
2029 /*
2030 * we only read stripe pages off the disk, set them
2031 * up to date if there were no errors
2032 */
2033 if (bio->bi_status)
2034 fail_bio_stripe(rbio, bio);
2035 else
2036 set_bio_pages_uptodate(bio);
2037 bio_put(bio);
2038
2039 if (!atomic_dec_and_test(&rbio->stripes_pending))
2040 return;
2041
2042 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
2043 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2044 else
2045 __raid_recover_end_io(rbio);
2046}
2047
2048/*
2049 * reads everything we need off the disk to reconstruct
2050 * the parity. endio handlers trigger final reconstruction
2051 * when the IO is done.
2052 *
2053 * This is used both for reads from the higher layers and for
2054 * parity construction required to finish a rmw cycle.
2055 */
2056static int __raid56_parity_recover(struct btrfs_raid_bio *rbio)
2057{
2058 int bios_to_read = 0;
2059 struct bio_list bio_list;
2060 int ret;
2061 int pagenr;
2062 int stripe;
2063 struct bio *bio;
2064
2065 bio_list_init(&bio_list);
2066
2067 ret = alloc_rbio_pages(rbio);
2068 if (ret)
2069 goto cleanup;
2070
2071 atomic_set(&rbio->error, 0);
2072
2073 /*
2074 * read everything that hasn't failed. Thanks to the
2075 * stripe cache, it is possible that some or all of these
2076 * pages are going to be uptodate.
2077 */
2078 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
2079 if (rbio->faila == stripe || rbio->failb == stripe) {
2080 atomic_inc(&rbio->error);
2081 continue;
2082 }
2083
2084 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
2085 struct page *p;
2086
2087 /*
2088 * the rmw code may have already read this
2089 * page in
2090 */
2091 p = rbio_stripe_page(rbio, stripe, pagenr);
2092 if (PageUptodate(p))
2093 continue;
2094
2095 ret = rbio_add_io_page(rbio, &bio_list,
2096 rbio_stripe_page(rbio, stripe, pagenr),
2097 stripe, pagenr, rbio->stripe_len);
2098 if (ret < 0)
2099 goto cleanup;
2100 }
2101 }
2102
2103 bios_to_read = bio_list_size(&bio_list);
2104 if (!bios_to_read) {
2105 /*
2106 * we might have no bios to read just because the pages
2107 * were up to date, or we might have no bios to read because
2108 * the devices were gone.
2109 */
2110 if (atomic_read(&rbio->error) <= rbio->bbio->max_errors) {
2111 __raid_recover_end_io(rbio);
2112 goto out;
2113 } else {
2114 goto cleanup;
2115 }
2116 }
2117
2118 /*
2119 * the bbio may be freed once we submit the last bio. Make sure
2120 * not to touch it after that
2121 */
2122 atomic_set(&rbio->stripes_pending, bios_to_read);
2123 while (1) {
2124 bio = bio_list_pop(&bio_list);
2125 if (!bio)
2126 break;
2127
2128 bio->bi_private = rbio;
2129 bio->bi_end_io = raid_recover_end_io;
2130 bio_set_op_attrs(bio, REQ_OP_READ, 0);
2131
2132 btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
2133
2134 submit_bio(bio);
2135 }
2136out:
2137 return 0;
2138
2139cleanup:
2140 if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
2141 rbio->operation == BTRFS_RBIO_REBUILD_MISSING)
2142 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2143
2144 while ((bio = bio_list_pop(&bio_list)))
2145 bio_put(bio);
2146
2147 return -EIO;
2148}
2149
2150/*
2151 * the main entry point for reads from the higher layers. This
2152 * is really only called when the normal read path had a failure,
2153 * so we assume the bio they send down corresponds to a failed part
2154 * of the drive.
2155 */
2156int raid56_parity_recover(struct btrfs_fs_info *fs_info, struct bio *bio,
2157 struct btrfs_bio *bbio, u64 stripe_len,
2158 int mirror_num, int generic_io)
2159{
2160 struct btrfs_raid_bio *rbio;
2161 int ret;
2162
2163 if (generic_io) {
2164 ASSERT(bbio->mirror_num == mirror_num);
2165 btrfs_io_bio(bio)->mirror_num = mirror_num;
2166 }
2167
2168 rbio = alloc_rbio(fs_info, bbio, stripe_len);
2169 if (IS_ERR(rbio)) {
2170 if (generic_io)
2171 btrfs_put_bbio(bbio);
2172 return PTR_ERR(rbio);
2173 }
2174
2175 rbio->operation = BTRFS_RBIO_READ_REBUILD;
2176 bio_list_add(&rbio->bio_list, bio);
2177 rbio->bio_list_bytes = bio->bi_iter.bi_size;
2178
2179 rbio->faila = find_logical_bio_stripe(rbio, bio);
2180 if (rbio->faila == -1) {
2181 btrfs_warn(fs_info,
2182 "%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)",
2183 __func__, (u64)bio->bi_iter.bi_sector << 9,
2184 (u64)bio->bi_iter.bi_size, bbio->map_type);
2185 if (generic_io)
2186 btrfs_put_bbio(bbio);
2187 kfree(rbio);
2188 return -EIO;
2189 }
2190
2191 if (generic_io) {
2192 btrfs_bio_counter_inc_noblocked(fs_info);
2193 rbio->generic_bio_cnt = 1;
2194 } else {
2195 btrfs_get_bbio(bbio);
2196 }
2197
2198 /*
2199 * Loop retry:
2200 * for 'mirror == 2', reconstruct from all other stripes.
2201 * for 'mirror_num > 2', select a stripe to fail on every retry.
2202 */
2203 if (mirror_num > 2) {
2204 /*
2205 * 'mirror == 3' is to fail the p stripe and
2206 * reconstruct from the q stripe. 'mirror > 3' is to
2207 * fail a data stripe and reconstruct from p+q stripe.
2208 */
2209 rbio->failb = rbio->real_stripes - (mirror_num - 1);
2210 ASSERT(rbio->failb > 0);
2211 if (rbio->failb <= rbio->faila)
2212 rbio->failb--;
2213 }
2214
2215 ret = lock_stripe_add(rbio);
2216
2217 /*
2218 * __raid56_parity_recover will end the bio with
2219 * any errors it hits. We don't want to return
2220 * its error value up the stack because our caller
2221 * will end up calling bio_endio with any nonzero
2222 * return
2223 */
2224 if (ret == 0)
2225 __raid56_parity_recover(rbio);
2226 /*
2227 * our rbio has been added to the list of
2228 * rbios that will be handled after the
2229 * currently lock owner is done
2230 */
2231 return 0;
2232
2233}
2234
2235static void rmw_work(struct btrfs_work *work)
2236{
2237 struct btrfs_raid_bio *rbio;
2238
2239 rbio = container_of(work, struct btrfs_raid_bio, work);
2240 raid56_rmw_stripe(rbio);
2241}
2242
2243static void read_rebuild_work(struct btrfs_work *work)
2244{
2245 struct btrfs_raid_bio *rbio;
2246
2247 rbio = container_of(work, struct btrfs_raid_bio, work);
2248 __raid56_parity_recover(rbio);
2249}
2250
2251/*
2252 * The following code is used to scrub/replace the parity stripe
2253 *
2254 * Caller must have already increased bio_counter for getting @bbio.
2255 *
2256 * Note: We need make sure all the pages that add into the scrub/replace
2257 * raid bio are correct and not be changed during the scrub/replace. That
2258 * is those pages just hold metadata or file data with checksum.
2259 */
2260
2261struct btrfs_raid_bio *
2262raid56_parity_alloc_scrub_rbio(struct btrfs_fs_info *fs_info, struct bio *bio,
2263 struct btrfs_bio *bbio, u64 stripe_len,
2264 struct btrfs_device *scrub_dev,
2265 unsigned long *dbitmap, int stripe_nsectors)
2266{
2267 struct btrfs_raid_bio *rbio;
2268 int i;
2269
2270 rbio = alloc_rbio(fs_info, bbio, stripe_len);
2271 if (IS_ERR(rbio))
2272 return NULL;
2273 bio_list_add(&rbio->bio_list, bio);
2274 /*
2275 * This is a special bio which is used to hold the completion handler
2276 * and make the scrub rbio is similar to the other types
2277 */
2278 ASSERT(!bio->bi_iter.bi_size);
2279 rbio->operation = BTRFS_RBIO_PARITY_SCRUB;
2280
2281 /*
2282 * After mapping bbio with BTRFS_MAP_WRITE, parities have been sorted
2283 * to the end position, so this search can start from the first parity
2284 * stripe.
2285 */
2286 for (i = rbio->nr_data; i < rbio->real_stripes; i++) {
2287 if (bbio->stripes[i].dev == scrub_dev) {
2288 rbio->scrubp = i;
2289 break;
2290 }
2291 }
2292 ASSERT(i < rbio->real_stripes);
2293
2294 /* Now we just support the sectorsize equals to page size */
2295 ASSERT(fs_info->sectorsize == PAGE_SIZE);
2296 ASSERT(rbio->stripe_npages == stripe_nsectors);
2297 bitmap_copy(rbio->dbitmap, dbitmap, stripe_nsectors);
2298
2299 /*
2300 * We have already increased bio_counter when getting bbio, record it
2301 * so we can free it at rbio_orig_end_io().
2302 */
2303 rbio->generic_bio_cnt = 1;
2304
2305 return rbio;
2306}
2307
2308/* Used for both parity scrub and missing. */
2309void raid56_add_scrub_pages(struct btrfs_raid_bio *rbio, struct page *page,
2310 u64 logical)
2311{
2312 int stripe_offset;
2313 int index;
2314
2315 ASSERT(logical >= rbio->bbio->raid_map[0]);
2316 ASSERT(logical + PAGE_SIZE <= rbio->bbio->raid_map[0] +
2317 rbio->stripe_len * rbio->nr_data);
2318 stripe_offset = (int)(logical - rbio->bbio->raid_map[0]);
2319 index = stripe_offset >> PAGE_SHIFT;
2320 rbio->bio_pages[index] = page;
2321}
2322
2323/*
2324 * We just scrub the parity that we have correct data on the same horizontal,
2325 * so we needn't allocate all pages for all the stripes.
2326 */
2327static int alloc_rbio_essential_pages(struct btrfs_raid_bio *rbio)
2328{
2329 int i;
2330 int bit;
2331 int index;
2332 struct page *page;
2333
2334 for_each_set_bit(bit, rbio->dbitmap, rbio->stripe_npages) {
2335 for (i = 0; i < rbio->real_stripes; i++) {
2336 index = i * rbio->stripe_npages + bit;
2337 if (rbio->stripe_pages[index])
2338 continue;
2339
2340 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2341 if (!page)
2342 return -ENOMEM;
2343 rbio->stripe_pages[index] = page;
2344 }
2345 }
2346 return 0;
2347}
2348
2349static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
2350 int need_check)
2351{
2352 struct btrfs_bio *bbio = rbio->bbio;
2353 void *pointers[rbio->real_stripes];
2354 DECLARE_BITMAP(pbitmap, rbio->stripe_npages);
2355 int nr_data = rbio->nr_data;
2356 int stripe;
2357 int pagenr;
2358 int p_stripe = -1;
2359 int q_stripe = -1;
2360 struct page *p_page = NULL;
2361 struct page *q_page = NULL;
2362 struct bio_list bio_list;
2363 struct bio *bio;
2364 int is_replace = 0;
2365 int ret;
2366
2367 bio_list_init(&bio_list);
2368
2369 if (rbio->real_stripes - rbio->nr_data == 1) {
2370 p_stripe = rbio->real_stripes - 1;
2371 } else if (rbio->real_stripes - rbio->nr_data == 2) {
2372 p_stripe = rbio->real_stripes - 2;
2373 q_stripe = rbio->real_stripes - 1;
2374 } else {
2375 BUG();
2376 }
2377
2378 if (bbio->num_tgtdevs && bbio->tgtdev_map[rbio->scrubp]) {
2379 is_replace = 1;
2380 bitmap_copy(pbitmap, rbio->dbitmap, rbio->stripe_npages);
2381 }
2382
2383 /*
2384 * Because the higher layers(scrubber) are unlikely to
2385 * use this area of the disk again soon, so don't cache
2386 * it.
2387 */
2388 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
2389
2390 if (!need_check)
2391 goto writeback;
2392
2393 p_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2394 if (!p_page)
2395 goto cleanup;
2396 SetPageUptodate(p_page);
2397
2398 if (q_stripe != -1) {
2399 q_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2400 if (!q_page) {
2401 __free_page(p_page);
2402 goto cleanup;
2403 }
2404 SetPageUptodate(q_page);
2405 }
2406
2407 atomic_set(&rbio->error, 0);
2408
2409 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2410 struct page *p;
2411 void *parity;
2412 /* first collect one page from each data stripe */
2413 for (stripe = 0; stripe < nr_data; stripe++) {
2414 p = page_in_rbio(rbio, stripe, pagenr, 0);
2415 pointers[stripe] = kmap(p);
2416 }
2417
2418 /* then add the parity stripe */
2419 pointers[stripe++] = kmap(p_page);
2420
2421 if (q_stripe != -1) {
2422
2423 /*
2424 * raid6, add the qstripe and call the
2425 * library function to fill in our p/q
2426 */
2427 pointers[stripe++] = kmap(q_page);
2428
2429 raid6_call.gen_syndrome(rbio->real_stripes, PAGE_SIZE,
2430 pointers);
2431 } else {
2432 /* raid5 */
2433 memcpy(pointers[nr_data], pointers[0], PAGE_SIZE);
2434 run_xor(pointers + 1, nr_data - 1, PAGE_SIZE);
2435 }
2436
2437 /* Check scrubbing parity and repair it */
2438 p = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2439 parity = kmap(p);
2440 if (memcmp(parity, pointers[rbio->scrubp], PAGE_SIZE))
2441 memcpy(parity, pointers[rbio->scrubp], PAGE_SIZE);
2442 else
2443 /* Parity is right, needn't writeback */
2444 bitmap_clear(rbio->dbitmap, pagenr, 1);
2445 kunmap(p);
2446
2447 for (stripe = 0; stripe < rbio->real_stripes; stripe++)
2448 kunmap(page_in_rbio(rbio, stripe, pagenr, 0));
2449 }
2450
2451 __free_page(p_page);
2452 if (q_page)
2453 __free_page(q_page);
2454
2455writeback:
2456 /*
2457 * time to start writing. Make bios for everything from the
2458 * higher layers (the bio_list in our rbio) and our p/q. Ignore
2459 * everything else.
2460 */
2461 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2462 struct page *page;
2463
2464 page = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2465 ret = rbio_add_io_page(rbio, &bio_list,
2466 page, rbio->scrubp, pagenr, rbio->stripe_len);
2467 if (ret)
2468 goto cleanup;
2469 }
2470
2471 if (!is_replace)
2472 goto submit_write;
2473
2474 for_each_set_bit(pagenr, pbitmap, rbio->stripe_npages) {
2475 struct page *page;
2476
2477 page = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2478 ret = rbio_add_io_page(rbio, &bio_list, page,
2479 bbio->tgtdev_map[rbio->scrubp],
2480 pagenr, rbio->stripe_len);
2481 if (ret)
2482 goto cleanup;
2483 }
2484
2485submit_write:
2486 nr_data = bio_list_size(&bio_list);
2487 if (!nr_data) {
2488 /* Every parity is right */
2489 rbio_orig_end_io(rbio, BLK_STS_OK);
2490 return;
2491 }
2492
2493 atomic_set(&rbio->stripes_pending, nr_data);
2494
2495 while (1) {
2496 bio = bio_list_pop(&bio_list);
2497 if (!bio)
2498 break;
2499
2500 bio->bi_private = rbio;
2501 bio->bi_end_io = raid_write_end_io;
2502 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
2503
2504 submit_bio(bio);
2505 }
2506 return;
2507
2508cleanup:
2509 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2510
2511 while ((bio = bio_list_pop(&bio_list)))
2512 bio_put(bio);
2513}
2514
2515static inline int is_data_stripe(struct btrfs_raid_bio *rbio, int stripe)
2516{
2517 if (stripe >= 0 && stripe < rbio->nr_data)
2518 return 1;
2519 return 0;
2520}
2521
2522/*
2523 * While we're doing the parity check and repair, we could have errors
2524 * in reading pages off the disk. This checks for errors and if we're
2525 * not able to read the page it'll trigger parity reconstruction. The
2526 * parity scrub will be finished after we've reconstructed the failed
2527 * stripes
2528 */
2529static void validate_rbio_for_parity_scrub(struct btrfs_raid_bio *rbio)
2530{
2531 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
2532 goto cleanup;
2533
2534 if (rbio->faila >= 0 || rbio->failb >= 0) {
2535 int dfail = 0, failp = -1;
2536
2537 if (is_data_stripe(rbio, rbio->faila))
2538 dfail++;
2539 else if (is_parity_stripe(rbio->faila))
2540 failp = rbio->faila;
2541
2542 if (is_data_stripe(rbio, rbio->failb))
2543 dfail++;
2544 else if (is_parity_stripe(rbio->failb))
2545 failp = rbio->failb;
2546
2547 /*
2548 * Because we can not use a scrubbing parity to repair
2549 * the data, so the capability of the repair is declined.
2550 * (In the case of RAID5, we can not repair anything)
2551 */
2552 if (dfail > rbio->bbio->max_errors - 1)
2553 goto cleanup;
2554
2555 /*
2556 * If all data is good, only parity is correctly, just
2557 * repair the parity.
2558 */
2559 if (dfail == 0) {
2560 finish_parity_scrub(rbio, 0);
2561 return;
2562 }
2563
2564 /*
2565 * Here means we got one corrupted data stripe and one
2566 * corrupted parity on RAID6, if the corrupted parity
2567 * is scrubbing parity, luckily, use the other one to repair
2568 * the data, or we can not repair the data stripe.
2569 */
2570 if (failp != rbio->scrubp)
2571 goto cleanup;
2572
2573 __raid_recover_end_io(rbio);
2574 } else {
2575 finish_parity_scrub(rbio, 1);
2576 }
2577 return;
2578
2579cleanup:
2580 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2581}
2582
2583/*
2584 * end io for the read phase of the rmw cycle. All the bios here are physical
2585 * stripe bios we've read from the disk so we can recalculate the parity of the
2586 * stripe.
2587 *
2588 * This will usually kick off finish_rmw once all the bios are read in, but it
2589 * may trigger parity reconstruction if we had any errors along the way
2590 */
2591static void raid56_parity_scrub_end_io(struct bio *bio)
2592{
2593 struct btrfs_raid_bio *rbio = bio->bi_private;
2594
2595 if (bio->bi_status)
2596 fail_bio_stripe(rbio, bio);
2597 else
2598 set_bio_pages_uptodate(bio);
2599
2600 bio_put(bio);
2601
2602 if (!atomic_dec_and_test(&rbio->stripes_pending))
2603 return;
2604
2605 /*
2606 * this will normally call finish_rmw to start our write
2607 * but if there are any failed stripes we'll reconstruct
2608 * from parity first
2609 */
2610 validate_rbio_for_parity_scrub(rbio);
2611}
2612
2613static void raid56_parity_scrub_stripe(struct btrfs_raid_bio *rbio)
2614{
2615 int bios_to_read = 0;
2616 struct bio_list bio_list;
2617 int ret;
2618 int pagenr;
2619 int stripe;
2620 struct bio *bio;
2621
2622 bio_list_init(&bio_list);
2623
2624 ret = alloc_rbio_essential_pages(rbio);
2625 if (ret)
2626 goto cleanup;
2627
2628 atomic_set(&rbio->error, 0);
2629 /*
2630 * build a list of bios to read all the missing parts of this
2631 * stripe
2632 */
2633 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
2634 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2635 struct page *page;
2636 /*
2637 * we want to find all the pages missing from
2638 * the rbio and read them from the disk. If
2639 * page_in_rbio finds a page in the bio list
2640 * we don't need to read it off the stripe.
2641 */
2642 page = page_in_rbio(rbio, stripe, pagenr, 1);
2643 if (page)
2644 continue;
2645
2646 page = rbio_stripe_page(rbio, stripe, pagenr);
2647 /*
2648 * the bio cache may have handed us an uptodate
2649 * page. If so, be happy and use it
2650 */
2651 if (PageUptodate(page))
2652 continue;
2653
2654 ret = rbio_add_io_page(rbio, &bio_list, page,
2655 stripe, pagenr, rbio->stripe_len);
2656 if (ret)
2657 goto cleanup;
2658 }
2659 }
2660
2661 bios_to_read = bio_list_size(&bio_list);
2662 if (!bios_to_read) {
2663 /*
2664 * this can happen if others have merged with
2665 * us, it means there is nothing left to read.
2666 * But if there are missing devices it may not be
2667 * safe to do the full stripe write yet.
2668 */
2669 goto finish;
2670 }
2671
2672 /*
2673 * the bbio may be freed once we submit the last bio. Make sure
2674 * not to touch it after that
2675 */
2676 atomic_set(&rbio->stripes_pending, bios_to_read);
2677 while (1) {
2678 bio = bio_list_pop(&bio_list);
2679 if (!bio)
2680 break;
2681
2682 bio->bi_private = rbio;
2683 bio->bi_end_io = raid56_parity_scrub_end_io;
2684 bio_set_op_attrs(bio, REQ_OP_READ, 0);
2685
2686 btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
2687
2688 submit_bio(bio);
2689 }
2690 /* the actual write will happen once the reads are done */
2691 return;
2692
2693cleanup:
2694 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2695
2696 while ((bio = bio_list_pop(&bio_list)))
2697 bio_put(bio);
2698
2699 return;
2700
2701finish:
2702 validate_rbio_for_parity_scrub(rbio);
2703}
2704
2705static void scrub_parity_work(struct btrfs_work *work)
2706{
2707 struct btrfs_raid_bio *rbio;
2708
2709 rbio = container_of(work, struct btrfs_raid_bio, work);
2710 raid56_parity_scrub_stripe(rbio);
2711}
2712
2713static void async_scrub_parity(struct btrfs_raid_bio *rbio)
2714{
2715 btrfs_init_work(&rbio->work, btrfs_rmw_helper,
2716 scrub_parity_work, NULL, NULL);
2717
2718 btrfs_queue_work(rbio->fs_info->rmw_workers, &rbio->work);
2719}
2720
2721void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio)
2722{
2723 if (!lock_stripe_add(rbio))
2724 async_scrub_parity(rbio);
2725}
2726
2727/* The following code is used for dev replace of a missing RAID 5/6 device. */
2728
2729struct btrfs_raid_bio *
2730raid56_alloc_missing_rbio(struct btrfs_fs_info *fs_info, struct bio *bio,
2731 struct btrfs_bio *bbio, u64 length)
2732{
2733 struct btrfs_raid_bio *rbio;
2734
2735 rbio = alloc_rbio(fs_info, bbio, length);
2736 if (IS_ERR(rbio))
2737 return NULL;
2738
2739 rbio->operation = BTRFS_RBIO_REBUILD_MISSING;
2740 bio_list_add(&rbio->bio_list, bio);
2741 /*
2742 * This is a special bio which is used to hold the completion handler
2743 * and make the scrub rbio is similar to the other types
2744 */
2745 ASSERT(!bio->bi_iter.bi_size);
2746
2747 rbio->faila = find_logical_bio_stripe(rbio, bio);
2748 if (rbio->faila == -1) {
2749 BUG();
2750 kfree(rbio);
2751 return NULL;
2752 }
2753
2754 /*
2755 * When we get bbio, we have already increased bio_counter, record it
2756 * so we can free it at rbio_orig_end_io()
2757 */
2758 rbio->generic_bio_cnt = 1;
2759
2760 return rbio;
2761}
2762
2763void raid56_submit_missing_rbio(struct btrfs_raid_bio *rbio)
2764{
2765 if (!lock_stripe_add(rbio))
2766 async_read_rebuild(rbio);
2767}