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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 "messages.h"
17#include "misc.h"
18#include "ctree.h"
19#include "disk-io.h"
20#include "volumes.h"
21#include "raid56.h"
22#include "async-thread.h"
23#include "file-item.h"
24#include "btrfs_inode.h"
25
26/* set when additional merges to this rbio are not allowed */
27#define RBIO_RMW_LOCKED_BIT 1
28
29/*
30 * set when this rbio is sitting in the hash, but it is just a cache
31 * of past RMW
32 */
33#define RBIO_CACHE_BIT 2
34
35/*
36 * set when it is safe to trust the stripe_pages for caching
37 */
38#define RBIO_CACHE_READY_BIT 3
39
40#define RBIO_CACHE_SIZE 1024
41
42#define BTRFS_STRIPE_HASH_TABLE_BITS 11
43
44/* Used by the raid56 code to lock stripes for read/modify/write */
45struct btrfs_stripe_hash {
46 struct list_head hash_list;
47 spinlock_t lock;
48};
49
50/* Used by the raid56 code to lock stripes for read/modify/write */
51struct btrfs_stripe_hash_table {
52 struct list_head stripe_cache;
53 spinlock_t cache_lock;
54 int cache_size;
55 struct btrfs_stripe_hash table[];
56};
57
58/*
59 * A bvec like structure to present a sector inside a page.
60 *
61 * Unlike bvec we don't need bvlen, as it's fixed to sectorsize.
62 */
63struct sector_ptr {
64 struct page *page;
65 unsigned int pgoff:24;
66 unsigned int uptodate:8;
67};
68
69static void rmw_rbio_work(struct work_struct *work);
70static void rmw_rbio_work_locked(struct work_struct *work);
71static void index_rbio_pages(struct btrfs_raid_bio *rbio);
72static int alloc_rbio_pages(struct btrfs_raid_bio *rbio);
73
74static int finish_parity_scrub(struct btrfs_raid_bio *rbio, int need_check);
75static void scrub_rbio_work_locked(struct work_struct *work);
76
77static void free_raid_bio_pointers(struct btrfs_raid_bio *rbio)
78{
79 bitmap_free(rbio->error_bitmap);
80 kfree(rbio->stripe_pages);
81 kfree(rbio->bio_sectors);
82 kfree(rbio->stripe_sectors);
83 kfree(rbio->finish_pointers);
84}
85
86static void free_raid_bio(struct btrfs_raid_bio *rbio)
87{
88 int i;
89
90 if (!refcount_dec_and_test(&rbio->refs))
91 return;
92
93 WARN_ON(!list_empty(&rbio->stripe_cache));
94 WARN_ON(!list_empty(&rbio->hash_list));
95 WARN_ON(!bio_list_empty(&rbio->bio_list));
96
97 for (i = 0; i < rbio->nr_pages; i++) {
98 if (rbio->stripe_pages[i]) {
99 __free_page(rbio->stripe_pages[i]);
100 rbio->stripe_pages[i] = NULL;
101 }
102 }
103
104 btrfs_put_bioc(rbio->bioc);
105 free_raid_bio_pointers(rbio);
106 kfree(rbio);
107}
108
109static void start_async_work(struct btrfs_raid_bio *rbio, work_func_t work_func)
110{
111 INIT_WORK(&rbio->work, work_func);
112 queue_work(rbio->bioc->fs_info->rmw_workers, &rbio->work);
113}
114
115/*
116 * the stripe hash table is used for locking, and to collect
117 * bios in hopes of making a full stripe
118 */
119int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info)
120{
121 struct btrfs_stripe_hash_table *table;
122 struct btrfs_stripe_hash_table *x;
123 struct btrfs_stripe_hash *cur;
124 struct btrfs_stripe_hash *h;
125 int num_entries = 1 << BTRFS_STRIPE_HASH_TABLE_BITS;
126 int i;
127
128 if (info->stripe_hash_table)
129 return 0;
130
131 /*
132 * The table is large, starting with order 4 and can go as high as
133 * order 7 in case lock debugging is turned on.
134 *
135 * Try harder to allocate and fallback to vmalloc to lower the chance
136 * of a failing mount.
137 */
138 table = kvzalloc(struct_size(table, table, num_entries), GFP_KERNEL);
139 if (!table)
140 return -ENOMEM;
141
142 spin_lock_init(&table->cache_lock);
143 INIT_LIST_HEAD(&table->stripe_cache);
144
145 h = table->table;
146
147 for (i = 0; i < num_entries; i++) {
148 cur = h + i;
149 INIT_LIST_HEAD(&cur->hash_list);
150 spin_lock_init(&cur->lock);
151 }
152
153 x = cmpxchg(&info->stripe_hash_table, NULL, table);
154 kvfree(x);
155 return 0;
156}
157
158/*
159 * caching an rbio means to copy anything from the
160 * bio_sectors array into the stripe_pages array. We
161 * use the page uptodate bit in the stripe cache array
162 * to indicate if it has valid data
163 *
164 * once the caching is done, we set the cache ready
165 * bit.
166 */
167static void cache_rbio_pages(struct btrfs_raid_bio *rbio)
168{
169 int i;
170 int ret;
171
172 ret = alloc_rbio_pages(rbio);
173 if (ret)
174 return;
175
176 for (i = 0; i < rbio->nr_sectors; i++) {
177 /* Some range not covered by bio (partial write), skip it */
178 if (!rbio->bio_sectors[i].page) {
179 /*
180 * Even if the sector is not covered by bio, if it is
181 * a data sector it should still be uptodate as it is
182 * read from disk.
183 */
184 if (i < rbio->nr_data * rbio->stripe_nsectors)
185 ASSERT(rbio->stripe_sectors[i].uptodate);
186 continue;
187 }
188
189 ASSERT(rbio->stripe_sectors[i].page);
190 memcpy_page(rbio->stripe_sectors[i].page,
191 rbio->stripe_sectors[i].pgoff,
192 rbio->bio_sectors[i].page,
193 rbio->bio_sectors[i].pgoff,
194 rbio->bioc->fs_info->sectorsize);
195 rbio->stripe_sectors[i].uptodate = 1;
196 }
197 set_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
198}
199
200/*
201 * we hash on the first logical address of the stripe
202 */
203static int rbio_bucket(struct btrfs_raid_bio *rbio)
204{
205 u64 num = rbio->bioc->raid_map[0];
206
207 /*
208 * we shift down quite a bit. We're using byte
209 * addressing, and most of the lower bits are zeros.
210 * This tends to upset hash_64, and it consistently
211 * returns just one or two different values.
212 *
213 * shifting off the lower bits fixes things.
214 */
215 return hash_64(num >> 16, BTRFS_STRIPE_HASH_TABLE_BITS);
216}
217
218static bool full_page_sectors_uptodate(struct btrfs_raid_bio *rbio,
219 unsigned int page_nr)
220{
221 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
222 const u32 sectors_per_page = PAGE_SIZE / sectorsize;
223 int i;
224
225 ASSERT(page_nr < rbio->nr_pages);
226
227 for (i = sectors_per_page * page_nr;
228 i < sectors_per_page * page_nr + sectors_per_page;
229 i++) {
230 if (!rbio->stripe_sectors[i].uptodate)
231 return false;
232 }
233 return true;
234}
235
236/*
237 * Update the stripe_sectors[] array to use correct page and pgoff
238 *
239 * Should be called every time any page pointer in stripes_pages[] got modified.
240 */
241static void index_stripe_sectors(struct btrfs_raid_bio *rbio)
242{
243 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
244 u32 offset;
245 int i;
246
247 for (i = 0, offset = 0; i < rbio->nr_sectors; i++, offset += sectorsize) {
248 int page_index = offset >> PAGE_SHIFT;
249
250 ASSERT(page_index < rbio->nr_pages);
251 rbio->stripe_sectors[i].page = rbio->stripe_pages[page_index];
252 rbio->stripe_sectors[i].pgoff = offset_in_page(offset);
253 }
254}
255
256static void steal_rbio_page(struct btrfs_raid_bio *src,
257 struct btrfs_raid_bio *dest, int page_nr)
258{
259 const u32 sectorsize = src->bioc->fs_info->sectorsize;
260 const u32 sectors_per_page = PAGE_SIZE / sectorsize;
261 int i;
262
263 if (dest->stripe_pages[page_nr])
264 __free_page(dest->stripe_pages[page_nr]);
265 dest->stripe_pages[page_nr] = src->stripe_pages[page_nr];
266 src->stripe_pages[page_nr] = NULL;
267
268 /* Also update the sector->uptodate bits. */
269 for (i = sectors_per_page * page_nr;
270 i < sectors_per_page * page_nr + sectors_per_page; i++)
271 dest->stripe_sectors[i].uptodate = true;
272}
273
274static bool is_data_stripe_page(struct btrfs_raid_bio *rbio, int page_nr)
275{
276 const int sector_nr = (page_nr << PAGE_SHIFT) >>
277 rbio->bioc->fs_info->sectorsize_bits;
278
279 /*
280 * We have ensured PAGE_SIZE is aligned with sectorsize, thus
281 * we won't have a page which is half data half parity.
282 *
283 * Thus if the first sector of the page belongs to data stripes, then
284 * the full page belongs to data stripes.
285 */
286 return (sector_nr < rbio->nr_data * rbio->stripe_nsectors);
287}
288
289/*
290 * Stealing an rbio means taking all the uptodate pages from the stripe array
291 * in the source rbio and putting them into the destination rbio.
292 *
293 * This will also update the involved stripe_sectors[] which are referring to
294 * the old pages.
295 */
296static void steal_rbio(struct btrfs_raid_bio *src, struct btrfs_raid_bio *dest)
297{
298 int i;
299
300 if (!test_bit(RBIO_CACHE_READY_BIT, &src->flags))
301 return;
302
303 for (i = 0; i < dest->nr_pages; i++) {
304 struct page *p = src->stripe_pages[i];
305
306 /*
307 * We don't need to steal P/Q pages as they will always be
308 * regenerated for RMW or full write anyway.
309 */
310 if (!is_data_stripe_page(src, i))
311 continue;
312
313 /*
314 * If @src already has RBIO_CACHE_READY_BIT, it should have
315 * all data stripe pages present and uptodate.
316 */
317 ASSERT(p);
318 ASSERT(full_page_sectors_uptodate(src, i));
319 steal_rbio_page(src, dest, i);
320 }
321 index_stripe_sectors(dest);
322 index_stripe_sectors(src);
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 /* Also inherit the bitmaps from @victim. */
338 bitmap_or(&dest->dbitmap, &victim->dbitmap, &dest->dbitmap,
339 dest->stripe_nsectors);
340 bio_list_init(&victim->bio_list);
341}
342
343/*
344 * used to prune items that are in the cache. The caller
345 * must hold the hash table lock.
346 */
347static void __remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
348{
349 int bucket = rbio_bucket(rbio);
350 struct btrfs_stripe_hash_table *table;
351 struct btrfs_stripe_hash *h;
352 int freeit = 0;
353
354 /*
355 * check the bit again under the hash table lock.
356 */
357 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
358 return;
359
360 table = rbio->bioc->fs_info->stripe_hash_table;
361 h = table->table + bucket;
362
363 /* hold the lock for the bucket because we may be
364 * removing it from the hash table
365 */
366 spin_lock(&h->lock);
367
368 /*
369 * hold the lock for the bio list because we need
370 * to make sure the bio list is empty
371 */
372 spin_lock(&rbio->bio_list_lock);
373
374 if (test_and_clear_bit(RBIO_CACHE_BIT, &rbio->flags)) {
375 list_del_init(&rbio->stripe_cache);
376 table->cache_size -= 1;
377 freeit = 1;
378
379 /* if the bio list isn't empty, this rbio is
380 * still involved in an IO. We take it out
381 * of the cache list, and drop the ref that
382 * was held for the list.
383 *
384 * If the bio_list was empty, we also remove
385 * the rbio from the hash_table, and drop
386 * the corresponding ref
387 */
388 if (bio_list_empty(&rbio->bio_list)) {
389 if (!list_empty(&rbio->hash_list)) {
390 list_del_init(&rbio->hash_list);
391 refcount_dec(&rbio->refs);
392 BUG_ON(!list_empty(&rbio->plug_list));
393 }
394 }
395 }
396
397 spin_unlock(&rbio->bio_list_lock);
398 spin_unlock(&h->lock);
399
400 if (freeit)
401 free_raid_bio(rbio);
402}
403
404/*
405 * prune a given rbio from the cache
406 */
407static void remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
408{
409 struct btrfs_stripe_hash_table *table;
410 unsigned long flags;
411
412 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
413 return;
414
415 table = rbio->bioc->fs_info->stripe_hash_table;
416
417 spin_lock_irqsave(&table->cache_lock, flags);
418 __remove_rbio_from_cache(rbio);
419 spin_unlock_irqrestore(&table->cache_lock, flags);
420}
421
422/*
423 * remove everything in the cache
424 */
425static void btrfs_clear_rbio_cache(struct btrfs_fs_info *info)
426{
427 struct btrfs_stripe_hash_table *table;
428 unsigned long flags;
429 struct btrfs_raid_bio *rbio;
430
431 table = info->stripe_hash_table;
432
433 spin_lock_irqsave(&table->cache_lock, flags);
434 while (!list_empty(&table->stripe_cache)) {
435 rbio = list_entry(table->stripe_cache.next,
436 struct btrfs_raid_bio,
437 stripe_cache);
438 __remove_rbio_from_cache(rbio);
439 }
440 spin_unlock_irqrestore(&table->cache_lock, flags);
441}
442
443/*
444 * remove all cached entries and free the hash table
445 * used by unmount
446 */
447void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info)
448{
449 if (!info->stripe_hash_table)
450 return;
451 btrfs_clear_rbio_cache(info);
452 kvfree(info->stripe_hash_table);
453 info->stripe_hash_table = NULL;
454}
455
456/*
457 * insert an rbio into the stripe cache. It
458 * must have already been prepared by calling
459 * cache_rbio_pages
460 *
461 * If this rbio was already cached, it gets
462 * moved to the front of the lru.
463 *
464 * If the size of the rbio cache is too big, we
465 * prune an item.
466 */
467static void cache_rbio(struct btrfs_raid_bio *rbio)
468{
469 struct btrfs_stripe_hash_table *table;
470 unsigned long flags;
471
472 if (!test_bit(RBIO_CACHE_READY_BIT, &rbio->flags))
473 return;
474
475 table = rbio->bioc->fs_info->stripe_hash_table;
476
477 spin_lock_irqsave(&table->cache_lock, flags);
478 spin_lock(&rbio->bio_list_lock);
479
480 /* bump our ref if we were not in the list before */
481 if (!test_and_set_bit(RBIO_CACHE_BIT, &rbio->flags))
482 refcount_inc(&rbio->refs);
483
484 if (!list_empty(&rbio->stripe_cache)){
485 list_move(&rbio->stripe_cache, &table->stripe_cache);
486 } else {
487 list_add(&rbio->stripe_cache, &table->stripe_cache);
488 table->cache_size += 1;
489 }
490
491 spin_unlock(&rbio->bio_list_lock);
492
493 if (table->cache_size > RBIO_CACHE_SIZE) {
494 struct btrfs_raid_bio *found;
495
496 found = list_entry(table->stripe_cache.prev,
497 struct btrfs_raid_bio,
498 stripe_cache);
499
500 if (found != rbio)
501 __remove_rbio_from_cache(found);
502 }
503
504 spin_unlock_irqrestore(&table->cache_lock, flags);
505}
506
507/*
508 * helper function to run the xor_blocks api. It is only
509 * able to do MAX_XOR_BLOCKS at a time, so we need to
510 * loop through.
511 */
512static void run_xor(void **pages, int src_cnt, ssize_t len)
513{
514 int src_off = 0;
515 int xor_src_cnt = 0;
516 void *dest = pages[src_cnt];
517
518 while(src_cnt > 0) {
519 xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS);
520 xor_blocks(xor_src_cnt, len, dest, pages + src_off);
521
522 src_cnt -= xor_src_cnt;
523 src_off += xor_src_cnt;
524 }
525}
526
527/*
528 * Returns true if the bio list inside this rbio covers an entire stripe (no
529 * rmw required).
530 */
531static int rbio_is_full(struct btrfs_raid_bio *rbio)
532{
533 unsigned long flags;
534 unsigned long size = rbio->bio_list_bytes;
535 int ret = 1;
536
537 spin_lock_irqsave(&rbio->bio_list_lock, flags);
538 if (size != rbio->nr_data * BTRFS_STRIPE_LEN)
539 ret = 0;
540 BUG_ON(size > rbio->nr_data * BTRFS_STRIPE_LEN);
541 spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
542
543 return ret;
544}
545
546/*
547 * returns 1 if it is safe to merge two rbios together.
548 * The merging is safe if the two rbios correspond to
549 * the same stripe and if they are both going in the same
550 * direction (read vs write), and if neither one is
551 * locked for final IO
552 *
553 * The caller is responsible for locking such that
554 * rmw_locked is safe to test
555 */
556static int rbio_can_merge(struct btrfs_raid_bio *last,
557 struct btrfs_raid_bio *cur)
558{
559 if (test_bit(RBIO_RMW_LOCKED_BIT, &last->flags) ||
560 test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags))
561 return 0;
562
563 /*
564 * we can't merge with cached rbios, since the
565 * idea is that when we merge the destination
566 * rbio is going to run our IO for us. We can
567 * steal from cached rbios though, other functions
568 * handle that.
569 */
570 if (test_bit(RBIO_CACHE_BIT, &last->flags) ||
571 test_bit(RBIO_CACHE_BIT, &cur->flags))
572 return 0;
573
574 if (last->bioc->raid_map[0] != cur->bioc->raid_map[0])
575 return 0;
576
577 /* we can't merge with different operations */
578 if (last->operation != cur->operation)
579 return 0;
580 /*
581 * We've need read the full stripe from the drive.
582 * check and repair the parity and write the new results.
583 *
584 * We're not allowed to add any new bios to the
585 * bio list here, anyone else that wants to
586 * change this stripe needs to do their own rmw.
587 */
588 if (last->operation == BTRFS_RBIO_PARITY_SCRUB)
589 return 0;
590
591 if (last->operation == BTRFS_RBIO_REBUILD_MISSING ||
592 last->operation == BTRFS_RBIO_READ_REBUILD)
593 return 0;
594
595 return 1;
596}
597
598static unsigned int rbio_stripe_sector_index(const struct btrfs_raid_bio *rbio,
599 unsigned int stripe_nr,
600 unsigned int sector_nr)
601{
602 ASSERT(stripe_nr < rbio->real_stripes);
603 ASSERT(sector_nr < rbio->stripe_nsectors);
604
605 return stripe_nr * rbio->stripe_nsectors + sector_nr;
606}
607
608/* Return a sector from rbio->stripe_sectors, not from the bio list */
609static struct sector_ptr *rbio_stripe_sector(const struct btrfs_raid_bio *rbio,
610 unsigned int stripe_nr,
611 unsigned int sector_nr)
612{
613 return &rbio->stripe_sectors[rbio_stripe_sector_index(rbio, stripe_nr,
614 sector_nr)];
615}
616
617/* Grab a sector inside P stripe */
618static struct sector_ptr *rbio_pstripe_sector(const struct btrfs_raid_bio *rbio,
619 unsigned int sector_nr)
620{
621 return rbio_stripe_sector(rbio, rbio->nr_data, sector_nr);
622}
623
624/* Grab a sector inside Q stripe, return NULL if not RAID6 */
625static struct sector_ptr *rbio_qstripe_sector(const struct btrfs_raid_bio *rbio,
626 unsigned int sector_nr)
627{
628 if (rbio->nr_data + 1 == rbio->real_stripes)
629 return NULL;
630 return rbio_stripe_sector(rbio, rbio->nr_data + 1, sector_nr);
631}
632
633/*
634 * The first stripe in the table for a logical address
635 * has the lock. rbios are added in one of three ways:
636 *
637 * 1) Nobody has the stripe locked yet. The rbio is given
638 * the lock and 0 is returned. The caller must start the IO
639 * themselves.
640 *
641 * 2) Someone has the stripe locked, but we're able to merge
642 * with the lock owner. The rbio is freed and the IO will
643 * start automatically along with the existing rbio. 1 is returned.
644 *
645 * 3) Someone has the stripe locked, but we're not able to merge.
646 * The rbio is added to the lock owner's plug list, or merged into
647 * an rbio already on the plug list. When the lock owner unlocks,
648 * the next rbio on the list is run and the IO is started automatically.
649 * 1 is returned
650 *
651 * If we return 0, the caller still owns the rbio and must continue with
652 * IO submission. If we return 1, the caller must assume the rbio has
653 * already been freed.
654 */
655static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
656{
657 struct btrfs_stripe_hash *h;
658 struct btrfs_raid_bio *cur;
659 struct btrfs_raid_bio *pending;
660 unsigned long flags;
661 struct btrfs_raid_bio *freeit = NULL;
662 struct btrfs_raid_bio *cache_drop = NULL;
663 int ret = 0;
664
665 h = rbio->bioc->fs_info->stripe_hash_table->table + rbio_bucket(rbio);
666
667 spin_lock_irqsave(&h->lock, flags);
668 list_for_each_entry(cur, &h->hash_list, hash_list) {
669 if (cur->bioc->raid_map[0] != rbio->bioc->raid_map[0])
670 continue;
671
672 spin_lock(&cur->bio_list_lock);
673
674 /* Can we steal this cached rbio's pages? */
675 if (bio_list_empty(&cur->bio_list) &&
676 list_empty(&cur->plug_list) &&
677 test_bit(RBIO_CACHE_BIT, &cur->flags) &&
678 !test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) {
679 list_del_init(&cur->hash_list);
680 refcount_dec(&cur->refs);
681
682 steal_rbio(cur, rbio);
683 cache_drop = cur;
684 spin_unlock(&cur->bio_list_lock);
685
686 goto lockit;
687 }
688
689 /* Can we merge into the lock owner? */
690 if (rbio_can_merge(cur, rbio)) {
691 merge_rbio(cur, rbio);
692 spin_unlock(&cur->bio_list_lock);
693 freeit = rbio;
694 ret = 1;
695 goto out;
696 }
697
698
699 /*
700 * We couldn't merge with the running rbio, see if we can merge
701 * with the pending ones. We don't have to check for rmw_locked
702 * because there is no way they are inside finish_rmw right now
703 */
704 list_for_each_entry(pending, &cur->plug_list, plug_list) {
705 if (rbio_can_merge(pending, rbio)) {
706 merge_rbio(pending, rbio);
707 spin_unlock(&cur->bio_list_lock);
708 freeit = rbio;
709 ret = 1;
710 goto out;
711 }
712 }
713
714 /*
715 * No merging, put us on the tail of the plug list, our rbio
716 * will be started with the currently running rbio unlocks
717 */
718 list_add_tail(&rbio->plug_list, &cur->plug_list);
719 spin_unlock(&cur->bio_list_lock);
720 ret = 1;
721 goto out;
722 }
723lockit:
724 refcount_inc(&rbio->refs);
725 list_add(&rbio->hash_list, &h->hash_list);
726out:
727 spin_unlock_irqrestore(&h->lock, flags);
728 if (cache_drop)
729 remove_rbio_from_cache(cache_drop);
730 if (freeit)
731 free_raid_bio(freeit);
732 return ret;
733}
734
735static void recover_rbio_work_locked(struct work_struct *work);
736
737/*
738 * called as rmw or parity rebuild is completed. If the plug list has more
739 * rbios waiting for this stripe, the next one on the list will be started
740 */
741static noinline void unlock_stripe(struct btrfs_raid_bio *rbio)
742{
743 int bucket;
744 struct btrfs_stripe_hash *h;
745 unsigned long flags;
746 int keep_cache = 0;
747
748 bucket = rbio_bucket(rbio);
749 h = rbio->bioc->fs_info->stripe_hash_table->table + bucket;
750
751 if (list_empty(&rbio->plug_list))
752 cache_rbio(rbio);
753
754 spin_lock_irqsave(&h->lock, flags);
755 spin_lock(&rbio->bio_list_lock);
756
757 if (!list_empty(&rbio->hash_list)) {
758 /*
759 * if we're still cached and there is no other IO
760 * to perform, just leave this rbio here for others
761 * to steal from later
762 */
763 if (list_empty(&rbio->plug_list) &&
764 test_bit(RBIO_CACHE_BIT, &rbio->flags)) {
765 keep_cache = 1;
766 clear_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
767 BUG_ON(!bio_list_empty(&rbio->bio_list));
768 goto done;
769 }
770
771 list_del_init(&rbio->hash_list);
772 refcount_dec(&rbio->refs);
773
774 /*
775 * we use the plug list to hold all the rbios
776 * waiting for the chance to lock this stripe.
777 * hand the lock over to one of them.
778 */
779 if (!list_empty(&rbio->plug_list)) {
780 struct btrfs_raid_bio *next;
781 struct list_head *head = rbio->plug_list.next;
782
783 next = list_entry(head, struct btrfs_raid_bio,
784 plug_list);
785
786 list_del_init(&rbio->plug_list);
787
788 list_add(&next->hash_list, &h->hash_list);
789 refcount_inc(&next->refs);
790 spin_unlock(&rbio->bio_list_lock);
791 spin_unlock_irqrestore(&h->lock, flags);
792
793 if (next->operation == BTRFS_RBIO_READ_REBUILD)
794 start_async_work(next, recover_rbio_work_locked);
795 else if (next->operation == BTRFS_RBIO_REBUILD_MISSING) {
796 steal_rbio(rbio, next);
797 start_async_work(next, recover_rbio_work_locked);
798 } else if (next->operation == BTRFS_RBIO_WRITE) {
799 steal_rbio(rbio, next);
800 start_async_work(next, rmw_rbio_work_locked);
801 } else if (next->operation == BTRFS_RBIO_PARITY_SCRUB) {
802 steal_rbio(rbio, next);
803 start_async_work(next, scrub_rbio_work_locked);
804 }
805
806 goto done_nolock;
807 }
808 }
809done:
810 spin_unlock(&rbio->bio_list_lock);
811 spin_unlock_irqrestore(&h->lock, flags);
812
813done_nolock:
814 if (!keep_cache)
815 remove_rbio_from_cache(rbio);
816}
817
818static void rbio_endio_bio_list(struct bio *cur, blk_status_t err)
819{
820 struct bio *next;
821
822 while (cur) {
823 next = cur->bi_next;
824 cur->bi_next = NULL;
825 cur->bi_status = err;
826 bio_endio(cur);
827 cur = next;
828 }
829}
830
831/*
832 * this frees the rbio and runs through all the bios in the
833 * bio_list and calls end_io on them
834 */
835static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, blk_status_t err)
836{
837 struct bio *cur = bio_list_get(&rbio->bio_list);
838 struct bio *extra;
839
840 kfree(rbio->csum_buf);
841 bitmap_free(rbio->csum_bitmap);
842 rbio->csum_buf = NULL;
843 rbio->csum_bitmap = NULL;
844
845 /*
846 * Clear the data bitmap, as the rbio may be cached for later usage.
847 * do this before before unlock_stripe() so there will be no new bio
848 * for this bio.
849 */
850 bitmap_clear(&rbio->dbitmap, 0, rbio->stripe_nsectors);
851
852 /*
853 * At this moment, rbio->bio_list is empty, however since rbio does not
854 * always have RBIO_RMW_LOCKED_BIT set and rbio is still linked on the
855 * hash list, rbio may be merged with others so that rbio->bio_list
856 * becomes non-empty.
857 * Once unlock_stripe() is done, rbio->bio_list will not be updated any
858 * more and we can call bio_endio() on all queued bios.
859 */
860 unlock_stripe(rbio);
861 extra = bio_list_get(&rbio->bio_list);
862 free_raid_bio(rbio);
863
864 rbio_endio_bio_list(cur, err);
865 if (extra)
866 rbio_endio_bio_list(extra, err);
867}
868
869/*
870 * Get a sector pointer specified by its @stripe_nr and @sector_nr.
871 *
872 * @rbio: The raid bio
873 * @stripe_nr: Stripe number, valid range [0, real_stripe)
874 * @sector_nr: Sector number inside the stripe,
875 * valid range [0, stripe_nsectors)
876 * @bio_list_only: Whether to use sectors inside the bio list only.
877 *
878 * The read/modify/write code wants to reuse the original bio page as much
879 * as possible, and only use stripe_sectors as fallback.
880 */
881static struct sector_ptr *sector_in_rbio(struct btrfs_raid_bio *rbio,
882 int stripe_nr, int sector_nr,
883 bool bio_list_only)
884{
885 struct sector_ptr *sector;
886 int index;
887
888 ASSERT(stripe_nr >= 0 && stripe_nr < rbio->real_stripes);
889 ASSERT(sector_nr >= 0 && sector_nr < rbio->stripe_nsectors);
890
891 index = stripe_nr * rbio->stripe_nsectors + sector_nr;
892 ASSERT(index >= 0 && index < rbio->nr_sectors);
893
894 spin_lock_irq(&rbio->bio_list_lock);
895 sector = &rbio->bio_sectors[index];
896 if (sector->page || bio_list_only) {
897 /* Don't return sector without a valid page pointer */
898 if (!sector->page)
899 sector = NULL;
900 spin_unlock_irq(&rbio->bio_list_lock);
901 return sector;
902 }
903 spin_unlock_irq(&rbio->bio_list_lock);
904
905 return &rbio->stripe_sectors[index];
906}
907
908/*
909 * allocation and initial setup for the btrfs_raid_bio. Not
910 * this does not allocate any pages for rbio->pages.
911 */
912static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info,
913 struct btrfs_io_context *bioc)
914{
915 const unsigned int real_stripes = bioc->num_stripes - bioc->num_tgtdevs;
916 const unsigned int stripe_npages = BTRFS_STRIPE_LEN >> PAGE_SHIFT;
917 const unsigned int num_pages = stripe_npages * real_stripes;
918 const unsigned int stripe_nsectors =
919 BTRFS_STRIPE_LEN >> fs_info->sectorsize_bits;
920 const unsigned int num_sectors = stripe_nsectors * real_stripes;
921 struct btrfs_raid_bio *rbio;
922
923 /* PAGE_SIZE must also be aligned to sectorsize for subpage support */
924 ASSERT(IS_ALIGNED(PAGE_SIZE, fs_info->sectorsize));
925 /*
926 * Our current stripe len should be fixed to 64k thus stripe_nsectors
927 * (at most 16) should be no larger than BITS_PER_LONG.
928 */
929 ASSERT(stripe_nsectors <= BITS_PER_LONG);
930
931 rbio = kzalloc(sizeof(*rbio), GFP_NOFS);
932 if (!rbio)
933 return ERR_PTR(-ENOMEM);
934 rbio->stripe_pages = kcalloc(num_pages, sizeof(struct page *),
935 GFP_NOFS);
936 rbio->bio_sectors = kcalloc(num_sectors, sizeof(struct sector_ptr),
937 GFP_NOFS);
938 rbio->stripe_sectors = kcalloc(num_sectors, sizeof(struct sector_ptr),
939 GFP_NOFS);
940 rbio->finish_pointers = kcalloc(real_stripes, sizeof(void *), GFP_NOFS);
941 rbio->error_bitmap = bitmap_zalloc(num_sectors, GFP_NOFS);
942
943 if (!rbio->stripe_pages || !rbio->bio_sectors || !rbio->stripe_sectors ||
944 !rbio->finish_pointers || !rbio->error_bitmap) {
945 free_raid_bio_pointers(rbio);
946 kfree(rbio);
947 return ERR_PTR(-ENOMEM);
948 }
949
950 bio_list_init(&rbio->bio_list);
951 init_waitqueue_head(&rbio->io_wait);
952 INIT_LIST_HEAD(&rbio->plug_list);
953 spin_lock_init(&rbio->bio_list_lock);
954 INIT_LIST_HEAD(&rbio->stripe_cache);
955 INIT_LIST_HEAD(&rbio->hash_list);
956 btrfs_get_bioc(bioc);
957 rbio->bioc = bioc;
958 rbio->nr_pages = num_pages;
959 rbio->nr_sectors = num_sectors;
960 rbio->real_stripes = real_stripes;
961 rbio->stripe_npages = stripe_npages;
962 rbio->stripe_nsectors = stripe_nsectors;
963 refcount_set(&rbio->refs, 1);
964 atomic_set(&rbio->stripes_pending, 0);
965
966 ASSERT(btrfs_nr_parity_stripes(bioc->map_type));
967 rbio->nr_data = real_stripes - btrfs_nr_parity_stripes(bioc->map_type);
968
969 return rbio;
970}
971
972/* allocate pages for all the stripes in the bio, including parity */
973static int alloc_rbio_pages(struct btrfs_raid_bio *rbio)
974{
975 int ret;
976
977 ret = btrfs_alloc_page_array(rbio->nr_pages, rbio->stripe_pages);
978 if (ret < 0)
979 return ret;
980 /* Mapping all sectors */
981 index_stripe_sectors(rbio);
982 return 0;
983}
984
985/* only allocate pages for p/q stripes */
986static int alloc_rbio_parity_pages(struct btrfs_raid_bio *rbio)
987{
988 const int data_pages = rbio->nr_data * rbio->stripe_npages;
989 int ret;
990
991 ret = btrfs_alloc_page_array(rbio->nr_pages - data_pages,
992 rbio->stripe_pages + data_pages);
993 if (ret < 0)
994 return ret;
995
996 index_stripe_sectors(rbio);
997 return 0;
998}
999
1000/*
1001 * Return the total numer of errors found in the vertical stripe of @sector_nr.
1002 *
1003 * @faila and @failb will also be updated to the first and second stripe
1004 * number of the errors.
1005 */
1006static int get_rbio_veritical_errors(struct btrfs_raid_bio *rbio, int sector_nr,
1007 int *faila, int *failb)
1008{
1009 int stripe_nr;
1010 int found_errors = 0;
1011
1012 if (faila || failb) {
1013 /*
1014 * Both @faila and @failb should be valid pointers if any of
1015 * them is specified.
1016 */
1017 ASSERT(faila && failb);
1018 *faila = -1;
1019 *failb = -1;
1020 }
1021
1022 for (stripe_nr = 0; stripe_nr < rbio->real_stripes; stripe_nr++) {
1023 int total_sector_nr = stripe_nr * rbio->stripe_nsectors + sector_nr;
1024
1025 if (test_bit(total_sector_nr, rbio->error_bitmap)) {
1026 found_errors++;
1027 if (faila) {
1028 /* Update faila and failb. */
1029 if (*faila < 0)
1030 *faila = stripe_nr;
1031 else if (*failb < 0)
1032 *failb = stripe_nr;
1033 }
1034 }
1035 }
1036 return found_errors;
1037}
1038
1039/*
1040 * Add a single sector @sector into our list of bios for IO.
1041 *
1042 * Return 0 if everything went well.
1043 * Return <0 for error.
1044 */
1045static int rbio_add_io_sector(struct btrfs_raid_bio *rbio,
1046 struct bio_list *bio_list,
1047 struct sector_ptr *sector,
1048 unsigned int stripe_nr,
1049 unsigned int sector_nr,
1050 enum req_op op)
1051{
1052 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
1053 struct bio *last = bio_list->tail;
1054 int ret;
1055 struct bio *bio;
1056 struct btrfs_io_stripe *stripe;
1057 u64 disk_start;
1058
1059 /*
1060 * Note: here stripe_nr has taken device replace into consideration,
1061 * thus it can be larger than rbio->real_stripe.
1062 * So here we check against bioc->num_stripes, not rbio->real_stripes.
1063 */
1064 ASSERT(stripe_nr >= 0 && stripe_nr < rbio->bioc->num_stripes);
1065 ASSERT(sector_nr >= 0 && sector_nr < rbio->stripe_nsectors);
1066 ASSERT(sector->page);
1067
1068 stripe = &rbio->bioc->stripes[stripe_nr];
1069 disk_start = stripe->physical + sector_nr * sectorsize;
1070
1071 /* if the device is missing, just fail this stripe */
1072 if (!stripe->dev->bdev) {
1073 int found_errors;
1074
1075 set_bit(stripe_nr * rbio->stripe_nsectors + sector_nr,
1076 rbio->error_bitmap);
1077
1078 /* Check if we have reached tolerance early. */
1079 found_errors = get_rbio_veritical_errors(rbio, sector_nr,
1080 NULL, NULL);
1081 if (found_errors > rbio->bioc->max_errors)
1082 return -EIO;
1083 return 0;
1084 }
1085
1086 /* see if we can add this page onto our existing bio */
1087 if (last) {
1088 u64 last_end = last->bi_iter.bi_sector << 9;
1089 last_end += last->bi_iter.bi_size;
1090
1091 /*
1092 * we can't merge these if they are from different
1093 * devices or if they are not contiguous
1094 */
1095 if (last_end == disk_start && !last->bi_status &&
1096 last->bi_bdev == stripe->dev->bdev) {
1097 ret = bio_add_page(last, sector->page, sectorsize,
1098 sector->pgoff);
1099 if (ret == sectorsize)
1100 return 0;
1101 }
1102 }
1103
1104 /* put a new bio on the list */
1105 bio = bio_alloc(stripe->dev->bdev,
1106 max(BTRFS_STRIPE_LEN >> PAGE_SHIFT, 1),
1107 op, GFP_NOFS);
1108 bio->bi_iter.bi_sector = disk_start >> 9;
1109 bio->bi_private = rbio;
1110
1111 bio_add_page(bio, sector->page, sectorsize, sector->pgoff);
1112 bio_list_add(bio_list, bio);
1113 return 0;
1114}
1115
1116static void index_one_bio(struct btrfs_raid_bio *rbio, struct bio *bio)
1117{
1118 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
1119 struct bio_vec bvec;
1120 struct bvec_iter iter;
1121 u32 offset = (bio->bi_iter.bi_sector << SECTOR_SHIFT) -
1122 rbio->bioc->raid_map[0];
1123
1124 bio_for_each_segment(bvec, bio, iter) {
1125 u32 bvec_offset;
1126
1127 for (bvec_offset = 0; bvec_offset < bvec.bv_len;
1128 bvec_offset += sectorsize, offset += sectorsize) {
1129 int index = offset / sectorsize;
1130 struct sector_ptr *sector = &rbio->bio_sectors[index];
1131
1132 sector->page = bvec.bv_page;
1133 sector->pgoff = bvec.bv_offset + bvec_offset;
1134 ASSERT(sector->pgoff < PAGE_SIZE);
1135 }
1136 }
1137}
1138
1139/*
1140 * helper function to walk our bio list and populate the bio_pages array with
1141 * the result. This seems expensive, but it is faster than constantly
1142 * searching through the bio list as we setup the IO in finish_rmw or stripe
1143 * reconstruction.
1144 *
1145 * This must be called before you trust the answers from page_in_rbio
1146 */
1147static void index_rbio_pages(struct btrfs_raid_bio *rbio)
1148{
1149 struct bio *bio;
1150
1151 spin_lock_irq(&rbio->bio_list_lock);
1152 bio_list_for_each(bio, &rbio->bio_list)
1153 index_one_bio(rbio, bio);
1154
1155 spin_unlock_irq(&rbio->bio_list_lock);
1156}
1157
1158static void bio_get_trace_info(struct btrfs_raid_bio *rbio, struct bio *bio,
1159 struct raid56_bio_trace_info *trace_info)
1160{
1161 const struct btrfs_io_context *bioc = rbio->bioc;
1162 int i;
1163
1164 ASSERT(bioc);
1165
1166 /* We rely on bio->bi_bdev to find the stripe number. */
1167 if (!bio->bi_bdev)
1168 goto not_found;
1169
1170 for (i = 0; i < bioc->num_stripes; i++) {
1171 if (bio->bi_bdev != bioc->stripes[i].dev->bdev)
1172 continue;
1173 trace_info->stripe_nr = i;
1174 trace_info->devid = bioc->stripes[i].dev->devid;
1175 trace_info->offset = (bio->bi_iter.bi_sector << SECTOR_SHIFT) -
1176 bioc->stripes[i].physical;
1177 return;
1178 }
1179
1180not_found:
1181 trace_info->devid = -1;
1182 trace_info->offset = -1;
1183 trace_info->stripe_nr = -1;
1184}
1185
1186/* Generate PQ for one veritical stripe. */
1187static void generate_pq_vertical(struct btrfs_raid_bio *rbio, int sectornr)
1188{
1189 void **pointers = rbio->finish_pointers;
1190 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
1191 struct sector_ptr *sector;
1192 int stripe;
1193 const bool has_qstripe = rbio->bioc->map_type & BTRFS_BLOCK_GROUP_RAID6;
1194
1195 /* First collect one sector from each data stripe */
1196 for (stripe = 0; stripe < rbio->nr_data; stripe++) {
1197 sector = sector_in_rbio(rbio, stripe, sectornr, 0);
1198 pointers[stripe] = kmap_local_page(sector->page) +
1199 sector->pgoff;
1200 }
1201
1202 /* Then add the parity stripe */
1203 sector = rbio_pstripe_sector(rbio, sectornr);
1204 sector->uptodate = 1;
1205 pointers[stripe++] = kmap_local_page(sector->page) + sector->pgoff;
1206
1207 if (has_qstripe) {
1208 /*
1209 * RAID6, add the qstripe and call the library function
1210 * to fill in our p/q
1211 */
1212 sector = rbio_qstripe_sector(rbio, sectornr);
1213 sector->uptodate = 1;
1214 pointers[stripe++] = kmap_local_page(sector->page) +
1215 sector->pgoff;
1216
1217 raid6_call.gen_syndrome(rbio->real_stripes, sectorsize,
1218 pointers);
1219 } else {
1220 /* raid5 */
1221 memcpy(pointers[rbio->nr_data], pointers[0], sectorsize);
1222 run_xor(pointers + 1, rbio->nr_data - 1, sectorsize);
1223 }
1224 for (stripe = stripe - 1; stripe >= 0; stripe--)
1225 kunmap_local(pointers[stripe]);
1226}
1227
1228static int rmw_assemble_write_bios(struct btrfs_raid_bio *rbio,
1229 struct bio_list *bio_list)
1230{
1231 struct bio *bio;
1232 /* The total sector number inside the full stripe. */
1233 int total_sector_nr;
1234 int sectornr;
1235 int stripe;
1236 int ret;
1237
1238 ASSERT(bio_list_size(bio_list) == 0);
1239
1240 /* We should have at least one data sector. */
1241 ASSERT(bitmap_weight(&rbio->dbitmap, rbio->stripe_nsectors));
1242
1243 /*
1244 * Reset errors, as we may have errors inherited from from degraded
1245 * write.
1246 */
1247 bitmap_clear(rbio->error_bitmap, 0, rbio->nr_sectors);
1248
1249 /*
1250 * Start assembly. Make bios for everything from the higher layers (the
1251 * bio_list in our rbio) and our P/Q. Ignore everything else.
1252 */
1253 for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
1254 total_sector_nr++) {
1255 struct sector_ptr *sector;
1256
1257 stripe = total_sector_nr / rbio->stripe_nsectors;
1258 sectornr = total_sector_nr % rbio->stripe_nsectors;
1259
1260 /* This vertical stripe has no data, skip it. */
1261 if (!test_bit(sectornr, &rbio->dbitmap))
1262 continue;
1263
1264 if (stripe < rbio->nr_data) {
1265 sector = sector_in_rbio(rbio, stripe, sectornr, 1);
1266 if (!sector)
1267 continue;
1268 } else {
1269 sector = rbio_stripe_sector(rbio, stripe, sectornr);
1270 }
1271
1272 ret = rbio_add_io_sector(rbio, bio_list, sector, stripe,
1273 sectornr, REQ_OP_WRITE);
1274 if (ret)
1275 goto error;
1276 }
1277
1278 if (likely(!rbio->bioc->num_tgtdevs))
1279 return 0;
1280
1281 /* Make a copy for the replace target device. */
1282 for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
1283 total_sector_nr++) {
1284 struct sector_ptr *sector;
1285
1286 stripe = total_sector_nr / rbio->stripe_nsectors;
1287 sectornr = total_sector_nr % rbio->stripe_nsectors;
1288
1289 if (!rbio->bioc->tgtdev_map[stripe]) {
1290 /*
1291 * We can skip the whole stripe completely, note
1292 * total_sector_nr will be increased by one anyway.
1293 */
1294 ASSERT(sectornr == 0);
1295 total_sector_nr += rbio->stripe_nsectors - 1;
1296 continue;
1297 }
1298
1299 /* This vertical stripe has no data, skip it. */
1300 if (!test_bit(sectornr, &rbio->dbitmap))
1301 continue;
1302
1303 if (stripe < rbio->nr_data) {
1304 sector = sector_in_rbio(rbio, stripe, sectornr, 1);
1305 if (!sector)
1306 continue;
1307 } else {
1308 sector = rbio_stripe_sector(rbio, stripe, sectornr);
1309 }
1310
1311 ret = rbio_add_io_sector(rbio, bio_list, sector,
1312 rbio->bioc->tgtdev_map[stripe],
1313 sectornr, REQ_OP_WRITE);
1314 if (ret)
1315 goto error;
1316 }
1317
1318 return 0;
1319error:
1320 while ((bio = bio_list_pop(bio_list)))
1321 bio_put(bio);
1322 return -EIO;
1323}
1324
1325static void set_rbio_range_error(struct btrfs_raid_bio *rbio, struct bio *bio)
1326{
1327 struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
1328 u32 offset = (bio->bi_iter.bi_sector << SECTOR_SHIFT) -
1329 rbio->bioc->raid_map[0];
1330 int total_nr_sector = offset >> fs_info->sectorsize_bits;
1331
1332 ASSERT(total_nr_sector < rbio->nr_data * rbio->stripe_nsectors);
1333
1334 bitmap_set(rbio->error_bitmap, total_nr_sector,
1335 bio->bi_iter.bi_size >> fs_info->sectorsize_bits);
1336
1337 /*
1338 * Special handling for raid56_alloc_missing_rbio() used by
1339 * scrub/replace. Unlike call path in raid56_parity_recover(), they
1340 * pass an empty bio here. Thus we have to find out the missing device
1341 * and mark the stripe error instead.
1342 */
1343 if (bio->bi_iter.bi_size == 0) {
1344 bool found_missing = false;
1345 int stripe_nr;
1346
1347 for (stripe_nr = 0; stripe_nr < rbio->real_stripes; stripe_nr++) {
1348 if (!rbio->bioc->stripes[stripe_nr].dev->bdev) {
1349 found_missing = true;
1350 bitmap_set(rbio->error_bitmap,
1351 stripe_nr * rbio->stripe_nsectors,
1352 rbio->stripe_nsectors);
1353 }
1354 }
1355 ASSERT(found_missing);
1356 }
1357}
1358
1359/*
1360 * For subpage case, we can no longer set page Uptodate directly for
1361 * stripe_pages[], thus we need to locate the sector.
1362 */
1363static struct sector_ptr *find_stripe_sector(struct btrfs_raid_bio *rbio,
1364 struct page *page,
1365 unsigned int pgoff)
1366{
1367 int i;
1368
1369 for (i = 0; i < rbio->nr_sectors; i++) {
1370 struct sector_ptr *sector = &rbio->stripe_sectors[i];
1371
1372 if (sector->page == page && sector->pgoff == pgoff)
1373 return sector;
1374 }
1375 return NULL;
1376}
1377
1378/*
1379 * this sets each page in the bio uptodate. It should only be used on private
1380 * rbio pages, nothing that comes in from the higher layers
1381 */
1382static void set_bio_pages_uptodate(struct btrfs_raid_bio *rbio, struct bio *bio)
1383{
1384 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
1385 struct bio_vec *bvec;
1386 struct bvec_iter_all iter_all;
1387
1388 ASSERT(!bio_flagged(bio, BIO_CLONED));
1389
1390 bio_for_each_segment_all(bvec, bio, iter_all) {
1391 struct sector_ptr *sector;
1392 int pgoff;
1393
1394 for (pgoff = bvec->bv_offset; pgoff - bvec->bv_offset < bvec->bv_len;
1395 pgoff += sectorsize) {
1396 sector = find_stripe_sector(rbio, bvec->bv_page, pgoff);
1397 ASSERT(sector);
1398 if (sector)
1399 sector->uptodate = 1;
1400 }
1401 }
1402}
1403
1404static int get_bio_sector_nr(struct btrfs_raid_bio *rbio, struct bio *bio)
1405{
1406 struct bio_vec *bv = bio_first_bvec_all(bio);
1407 int i;
1408
1409 for (i = 0; i < rbio->nr_sectors; i++) {
1410 struct sector_ptr *sector;
1411
1412 sector = &rbio->stripe_sectors[i];
1413 if (sector->page == bv->bv_page && sector->pgoff == bv->bv_offset)
1414 break;
1415 sector = &rbio->bio_sectors[i];
1416 if (sector->page == bv->bv_page && sector->pgoff == bv->bv_offset)
1417 break;
1418 }
1419 ASSERT(i < rbio->nr_sectors);
1420 return i;
1421}
1422
1423static void rbio_update_error_bitmap(struct btrfs_raid_bio *rbio, struct bio *bio)
1424{
1425 int total_sector_nr = get_bio_sector_nr(rbio, bio);
1426 u32 bio_size = 0;
1427 struct bio_vec *bvec;
1428 struct bvec_iter_all iter_all;
1429 int i;
1430
1431 bio_for_each_segment_all(bvec, bio, iter_all)
1432 bio_size += bvec->bv_len;
1433
1434 /*
1435 * Since we can have multiple bios touching the error_bitmap, we cannot
1436 * call bitmap_set() without protection.
1437 *
1438 * Instead use set_bit() for each bit, as set_bit() itself is atomic.
1439 */
1440 for (i = total_sector_nr; i < total_sector_nr +
1441 (bio_size >> rbio->bioc->fs_info->sectorsize_bits); i++)
1442 set_bit(i, rbio->error_bitmap);
1443}
1444
1445/* Verify the data sectors at read time. */
1446static void verify_bio_data_sectors(struct btrfs_raid_bio *rbio,
1447 struct bio *bio)
1448{
1449 struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
1450 int total_sector_nr = get_bio_sector_nr(rbio, bio);
1451 struct bio_vec *bvec;
1452 struct bvec_iter_all iter_all;
1453
1454 /* No data csum for the whole stripe, no need to verify. */
1455 if (!rbio->csum_bitmap || !rbio->csum_buf)
1456 return;
1457
1458 /* P/Q stripes, they have no data csum to verify against. */
1459 if (total_sector_nr >= rbio->nr_data * rbio->stripe_nsectors)
1460 return;
1461
1462 bio_for_each_segment_all(bvec, bio, iter_all) {
1463 int bv_offset;
1464
1465 for (bv_offset = bvec->bv_offset;
1466 bv_offset < bvec->bv_offset + bvec->bv_len;
1467 bv_offset += fs_info->sectorsize, total_sector_nr++) {
1468 u8 csum_buf[BTRFS_CSUM_SIZE];
1469 u8 *expected_csum = rbio->csum_buf +
1470 total_sector_nr * fs_info->csum_size;
1471 int ret;
1472
1473 /* No csum for this sector, skip to the next sector. */
1474 if (!test_bit(total_sector_nr, rbio->csum_bitmap))
1475 continue;
1476
1477 ret = btrfs_check_sector_csum(fs_info, bvec->bv_page,
1478 bv_offset, csum_buf, expected_csum);
1479 if (ret < 0)
1480 set_bit(total_sector_nr, rbio->error_bitmap);
1481 }
1482 }
1483}
1484
1485static void raid_wait_read_end_io(struct bio *bio)
1486{
1487 struct btrfs_raid_bio *rbio = bio->bi_private;
1488
1489 if (bio->bi_status) {
1490 rbio_update_error_bitmap(rbio, bio);
1491 } else {
1492 set_bio_pages_uptodate(rbio, bio);
1493 verify_bio_data_sectors(rbio, bio);
1494 }
1495
1496 bio_put(bio);
1497 if (atomic_dec_and_test(&rbio->stripes_pending))
1498 wake_up(&rbio->io_wait);
1499}
1500
1501static void submit_read_bios(struct btrfs_raid_bio *rbio,
1502 struct bio_list *bio_list)
1503{
1504 struct bio *bio;
1505
1506 atomic_set(&rbio->stripes_pending, bio_list_size(bio_list));
1507 while ((bio = bio_list_pop(bio_list))) {
1508 bio->bi_end_io = raid_wait_read_end_io;
1509
1510 if (trace_raid56_scrub_read_recover_enabled()) {
1511 struct raid56_bio_trace_info trace_info = { 0 };
1512
1513 bio_get_trace_info(rbio, bio, &trace_info);
1514 trace_raid56_scrub_read_recover(rbio, bio, &trace_info);
1515 }
1516 submit_bio(bio);
1517 }
1518}
1519
1520static int rmw_assemble_read_bios(struct btrfs_raid_bio *rbio,
1521 struct bio_list *bio_list)
1522{
1523 struct bio *bio;
1524 int total_sector_nr;
1525 int ret = 0;
1526
1527 ASSERT(bio_list_size(bio_list) == 0);
1528
1529 /*
1530 * Build a list of bios to read all sectors (including data and P/Q).
1531 *
1532 * This behaviro is to compensate the later csum verification and
1533 * recovery.
1534 */
1535 for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
1536 total_sector_nr++) {
1537 struct sector_ptr *sector;
1538 int stripe = total_sector_nr / rbio->stripe_nsectors;
1539 int sectornr = total_sector_nr % rbio->stripe_nsectors;
1540
1541 sector = rbio_stripe_sector(rbio, stripe, sectornr);
1542 ret = rbio_add_io_sector(rbio, bio_list, sector,
1543 stripe, sectornr, REQ_OP_READ);
1544 if (ret)
1545 goto cleanup;
1546 }
1547 return 0;
1548
1549cleanup:
1550 while ((bio = bio_list_pop(bio_list)))
1551 bio_put(bio);
1552 return ret;
1553}
1554
1555static int alloc_rbio_data_pages(struct btrfs_raid_bio *rbio)
1556{
1557 const int data_pages = rbio->nr_data * rbio->stripe_npages;
1558 int ret;
1559
1560 ret = btrfs_alloc_page_array(data_pages, rbio->stripe_pages);
1561 if (ret < 0)
1562 return ret;
1563
1564 index_stripe_sectors(rbio);
1565 return 0;
1566}
1567
1568/*
1569 * We use plugging call backs to collect full stripes.
1570 * Any time we get a partial stripe write while plugged
1571 * we collect it into a list. When the unplug comes down,
1572 * we sort the list by logical block number and merge
1573 * everything we can into the same rbios
1574 */
1575struct btrfs_plug_cb {
1576 struct blk_plug_cb cb;
1577 struct btrfs_fs_info *info;
1578 struct list_head rbio_list;
1579 struct work_struct work;
1580};
1581
1582/*
1583 * rbios on the plug list are sorted for easier merging.
1584 */
1585static int plug_cmp(void *priv, const struct list_head *a,
1586 const struct list_head *b)
1587{
1588 const struct btrfs_raid_bio *ra = container_of(a, struct btrfs_raid_bio,
1589 plug_list);
1590 const struct btrfs_raid_bio *rb = container_of(b, struct btrfs_raid_bio,
1591 plug_list);
1592 u64 a_sector = ra->bio_list.head->bi_iter.bi_sector;
1593 u64 b_sector = rb->bio_list.head->bi_iter.bi_sector;
1594
1595 if (a_sector < b_sector)
1596 return -1;
1597 if (a_sector > b_sector)
1598 return 1;
1599 return 0;
1600}
1601
1602static void raid_unplug(struct blk_plug_cb *cb, bool from_schedule)
1603{
1604 struct btrfs_plug_cb *plug = container_of(cb, struct btrfs_plug_cb, cb);
1605 struct btrfs_raid_bio *cur;
1606 struct btrfs_raid_bio *last = NULL;
1607
1608 list_sort(NULL, &plug->rbio_list, plug_cmp);
1609
1610 while (!list_empty(&plug->rbio_list)) {
1611 cur = list_entry(plug->rbio_list.next,
1612 struct btrfs_raid_bio, plug_list);
1613 list_del_init(&cur->plug_list);
1614
1615 if (rbio_is_full(cur)) {
1616 /* We have a full stripe, queue it down. */
1617 start_async_work(cur, rmw_rbio_work);
1618 continue;
1619 }
1620 if (last) {
1621 if (rbio_can_merge(last, cur)) {
1622 merge_rbio(last, cur);
1623 free_raid_bio(cur);
1624 continue;
1625 }
1626 start_async_work(last, rmw_rbio_work);
1627 }
1628 last = cur;
1629 }
1630 if (last)
1631 start_async_work(last, rmw_rbio_work);
1632 kfree(plug);
1633}
1634
1635/* Add the original bio into rbio->bio_list, and update rbio::dbitmap. */
1636static void rbio_add_bio(struct btrfs_raid_bio *rbio, struct bio *orig_bio)
1637{
1638 const struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
1639 const u64 orig_logical = orig_bio->bi_iter.bi_sector << SECTOR_SHIFT;
1640 const u64 full_stripe_start = rbio->bioc->raid_map[0];
1641 const u32 orig_len = orig_bio->bi_iter.bi_size;
1642 const u32 sectorsize = fs_info->sectorsize;
1643 u64 cur_logical;
1644
1645 ASSERT(orig_logical >= full_stripe_start &&
1646 orig_logical + orig_len <= full_stripe_start +
1647 rbio->nr_data * BTRFS_STRIPE_LEN);
1648
1649 bio_list_add(&rbio->bio_list, orig_bio);
1650 rbio->bio_list_bytes += orig_bio->bi_iter.bi_size;
1651
1652 /* Update the dbitmap. */
1653 for (cur_logical = orig_logical; cur_logical < orig_logical + orig_len;
1654 cur_logical += sectorsize) {
1655 int bit = ((u32)(cur_logical - full_stripe_start) >>
1656 fs_info->sectorsize_bits) % rbio->stripe_nsectors;
1657
1658 set_bit(bit, &rbio->dbitmap);
1659 }
1660}
1661
1662/*
1663 * our main entry point for writes from the rest of the FS.
1664 */
1665void raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc)
1666{
1667 struct btrfs_fs_info *fs_info = bioc->fs_info;
1668 struct btrfs_raid_bio *rbio;
1669 struct btrfs_plug_cb *plug = NULL;
1670 struct blk_plug_cb *cb;
1671 int ret = 0;
1672
1673 rbio = alloc_rbio(fs_info, bioc);
1674 if (IS_ERR(rbio)) {
1675 ret = PTR_ERR(rbio);
1676 goto fail;
1677 }
1678 rbio->operation = BTRFS_RBIO_WRITE;
1679 rbio_add_bio(rbio, bio);
1680
1681 /*
1682 * Don't plug on full rbios, just get them out the door
1683 * as quickly as we can
1684 */
1685 if (rbio_is_full(rbio))
1686 goto queue_rbio;
1687
1688 cb = blk_check_plugged(raid_unplug, fs_info, sizeof(*plug));
1689 if (cb) {
1690 plug = container_of(cb, struct btrfs_plug_cb, cb);
1691 if (!plug->info) {
1692 plug->info = fs_info;
1693 INIT_LIST_HEAD(&plug->rbio_list);
1694 }
1695 list_add_tail(&rbio->plug_list, &plug->rbio_list);
1696 return;
1697 }
1698queue_rbio:
1699 /*
1700 * Either we don't have any existing plug, or we're doing a full stripe,
1701 * can queue the rmw work now.
1702 */
1703 start_async_work(rbio, rmw_rbio_work);
1704
1705 return;
1706
1707fail:
1708 bio->bi_status = errno_to_blk_status(ret);
1709 bio_endio(bio);
1710}
1711
1712static int verify_one_sector(struct btrfs_raid_bio *rbio,
1713 int stripe_nr, int sector_nr)
1714{
1715 struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
1716 struct sector_ptr *sector;
1717 u8 csum_buf[BTRFS_CSUM_SIZE];
1718 u8 *csum_expected;
1719 int ret;
1720
1721 if (!rbio->csum_bitmap || !rbio->csum_buf)
1722 return 0;
1723
1724 /* No way to verify P/Q as they are not covered by data csum. */
1725 if (stripe_nr >= rbio->nr_data)
1726 return 0;
1727 /*
1728 * If we're rebuilding a read, we have to use pages from the
1729 * bio list if possible.
1730 */
1731 if ((rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1732 rbio->operation == BTRFS_RBIO_REBUILD_MISSING)) {
1733 sector = sector_in_rbio(rbio, stripe_nr, sector_nr, 0);
1734 } else {
1735 sector = rbio_stripe_sector(rbio, stripe_nr, sector_nr);
1736 }
1737
1738 ASSERT(sector->page);
1739
1740 csum_expected = rbio->csum_buf +
1741 (stripe_nr * rbio->stripe_nsectors + sector_nr) *
1742 fs_info->csum_size;
1743 ret = btrfs_check_sector_csum(fs_info, sector->page, sector->pgoff,
1744 csum_buf, csum_expected);
1745 return ret;
1746}
1747
1748/*
1749 * Recover a vertical stripe specified by @sector_nr.
1750 * @*pointers are the pre-allocated pointers by the caller, so we don't
1751 * need to allocate/free the pointers again and again.
1752 */
1753static int recover_vertical(struct btrfs_raid_bio *rbio, int sector_nr,
1754 void **pointers, void **unmap_array)
1755{
1756 struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
1757 struct sector_ptr *sector;
1758 const u32 sectorsize = fs_info->sectorsize;
1759 int found_errors;
1760 int faila;
1761 int failb;
1762 int stripe_nr;
1763 int ret = 0;
1764
1765 /*
1766 * Now we just use bitmap to mark the horizontal stripes in
1767 * which we have data when doing parity scrub.
1768 */
1769 if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB &&
1770 !test_bit(sector_nr, &rbio->dbitmap))
1771 return 0;
1772
1773 found_errors = get_rbio_veritical_errors(rbio, sector_nr, &faila,
1774 &failb);
1775 /*
1776 * No errors in the veritical stripe, skip it. Can happen for recovery
1777 * which only part of a stripe failed csum check.
1778 */
1779 if (!found_errors)
1780 return 0;
1781
1782 if (found_errors > rbio->bioc->max_errors)
1783 return -EIO;
1784
1785 /*
1786 * Setup our array of pointers with sectors from each stripe
1787 *
1788 * NOTE: store a duplicate array of pointers to preserve the
1789 * pointer order.
1790 */
1791 for (stripe_nr = 0; stripe_nr < rbio->real_stripes; stripe_nr++) {
1792 /*
1793 * If we're rebuilding a read, we have to use pages from the
1794 * bio list if possible.
1795 */
1796 if ((rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1797 rbio->operation == BTRFS_RBIO_REBUILD_MISSING)) {
1798 sector = sector_in_rbio(rbio, stripe_nr, sector_nr, 0);
1799 } else {
1800 sector = rbio_stripe_sector(rbio, stripe_nr, sector_nr);
1801 }
1802 ASSERT(sector->page);
1803 pointers[stripe_nr] = kmap_local_page(sector->page) +
1804 sector->pgoff;
1805 unmap_array[stripe_nr] = pointers[stripe_nr];
1806 }
1807
1808 /* All raid6 handling here */
1809 if (rbio->bioc->map_type & BTRFS_BLOCK_GROUP_RAID6) {
1810 /* Single failure, rebuild from parity raid5 style */
1811 if (failb < 0) {
1812 if (faila == rbio->nr_data)
1813 /*
1814 * Just the P stripe has failed, without
1815 * a bad data or Q stripe.
1816 * We have nothing to do, just skip the
1817 * recovery for this stripe.
1818 */
1819 goto cleanup;
1820 /*
1821 * a single failure in raid6 is rebuilt
1822 * in the pstripe code below
1823 */
1824 goto pstripe;
1825 }
1826
1827 /*
1828 * If the q stripe is failed, do a pstripe reconstruction from
1829 * the xors.
1830 * If both the q stripe and the P stripe are failed, we're
1831 * here due to a crc mismatch and we can't give them the
1832 * data they want.
1833 */
1834 if (rbio->bioc->raid_map[failb] == RAID6_Q_STRIPE) {
1835 if (rbio->bioc->raid_map[faila] ==
1836 RAID5_P_STRIPE)
1837 /*
1838 * Only P and Q are corrupted.
1839 * We only care about data stripes recovery,
1840 * can skip this vertical stripe.
1841 */
1842 goto cleanup;
1843 /*
1844 * Otherwise we have one bad data stripe and
1845 * a good P stripe. raid5!
1846 */
1847 goto pstripe;
1848 }
1849
1850 if (rbio->bioc->raid_map[failb] == RAID5_P_STRIPE) {
1851 raid6_datap_recov(rbio->real_stripes, sectorsize,
1852 faila, pointers);
1853 } else {
1854 raid6_2data_recov(rbio->real_stripes, sectorsize,
1855 faila, failb, pointers);
1856 }
1857 } else {
1858 void *p;
1859
1860 /* Rebuild from P stripe here (raid5 or raid6). */
1861 ASSERT(failb == -1);
1862pstripe:
1863 /* Copy parity block into failed block to start with */
1864 memcpy(pointers[faila], pointers[rbio->nr_data], sectorsize);
1865
1866 /* Rearrange the pointer array */
1867 p = pointers[faila];
1868 for (stripe_nr = faila; stripe_nr < rbio->nr_data - 1;
1869 stripe_nr++)
1870 pointers[stripe_nr] = pointers[stripe_nr + 1];
1871 pointers[rbio->nr_data - 1] = p;
1872
1873 /* Xor in the rest */
1874 run_xor(pointers, rbio->nr_data - 1, sectorsize);
1875
1876 }
1877
1878 /*
1879 * No matter if this is a RMW or recovery, we should have all
1880 * failed sectors repaired in the vertical stripe, thus they are now
1881 * uptodate.
1882 * Especially if we determine to cache the rbio, we need to
1883 * have at least all data sectors uptodate.
1884 *
1885 * If possible, also check if the repaired sector matches its data
1886 * checksum.
1887 */
1888 if (faila >= 0) {
1889 ret = verify_one_sector(rbio, faila, sector_nr);
1890 if (ret < 0)
1891 goto cleanup;
1892
1893 sector = rbio_stripe_sector(rbio, faila, sector_nr);
1894 sector->uptodate = 1;
1895 }
1896 if (failb >= 0) {
1897 ret = verify_one_sector(rbio, failb, sector_nr);
1898 if (ret < 0)
1899 goto cleanup;
1900
1901 sector = rbio_stripe_sector(rbio, failb, sector_nr);
1902 sector->uptodate = 1;
1903 }
1904
1905cleanup:
1906 for (stripe_nr = rbio->real_stripes - 1; stripe_nr >= 0; stripe_nr--)
1907 kunmap_local(unmap_array[stripe_nr]);
1908 return ret;
1909}
1910
1911static int recover_sectors(struct btrfs_raid_bio *rbio)
1912{
1913 void **pointers = NULL;
1914 void **unmap_array = NULL;
1915 int sectornr;
1916 int ret = 0;
1917
1918 /*
1919 * @pointers array stores the pointer for each sector.
1920 *
1921 * @unmap_array stores copy of pointers that does not get reordered
1922 * during reconstruction so that kunmap_local works.
1923 */
1924 pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
1925 unmap_array = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
1926 if (!pointers || !unmap_array) {
1927 ret = -ENOMEM;
1928 goto out;
1929 }
1930
1931 if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1932 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) {
1933 spin_lock_irq(&rbio->bio_list_lock);
1934 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1935 spin_unlock_irq(&rbio->bio_list_lock);
1936 }
1937
1938 index_rbio_pages(rbio);
1939
1940 for (sectornr = 0; sectornr < rbio->stripe_nsectors; sectornr++) {
1941 ret = recover_vertical(rbio, sectornr, pointers, unmap_array);
1942 if (ret < 0)
1943 break;
1944 }
1945
1946out:
1947 kfree(pointers);
1948 kfree(unmap_array);
1949 return ret;
1950}
1951
1952static int recover_assemble_read_bios(struct btrfs_raid_bio *rbio,
1953 struct bio_list *bio_list)
1954{
1955 struct bio *bio;
1956 int total_sector_nr;
1957 int ret = 0;
1958
1959 ASSERT(bio_list_size(bio_list) == 0);
1960 /*
1961 * Read everything that hasn't failed. However this time we will
1962 * not trust any cached sector.
1963 * As we may read out some stale data but higher layer is not reading
1964 * that stale part.
1965 *
1966 * So here we always re-read everything in recovery path.
1967 */
1968 for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
1969 total_sector_nr++) {
1970 int stripe = total_sector_nr / rbio->stripe_nsectors;
1971 int sectornr = total_sector_nr % rbio->stripe_nsectors;
1972 struct sector_ptr *sector;
1973
1974 /*
1975 * Skip the range which has error. It can be a range which is
1976 * marked error (for csum mismatch), or it can be a missing
1977 * device.
1978 */
1979 if (!rbio->bioc->stripes[stripe].dev->bdev ||
1980 test_bit(total_sector_nr, rbio->error_bitmap)) {
1981 /*
1982 * Also set the error bit for missing device, which
1983 * may not yet have its error bit set.
1984 */
1985 set_bit(total_sector_nr, rbio->error_bitmap);
1986 continue;
1987 }
1988
1989 sector = rbio_stripe_sector(rbio, stripe, sectornr);
1990 ret = rbio_add_io_sector(rbio, bio_list, sector, stripe,
1991 sectornr, REQ_OP_READ);
1992 if (ret < 0)
1993 goto error;
1994 }
1995 return 0;
1996error:
1997 while ((bio = bio_list_pop(bio_list)))
1998 bio_put(bio);
1999
2000 return -EIO;
2001}
2002
2003static int recover_rbio(struct btrfs_raid_bio *rbio)
2004{
2005 struct bio_list bio_list;
2006 struct bio *bio;
2007 int ret;
2008
2009 /*
2010 * Either we're doing recover for a read failure or degraded write,
2011 * caller should have set error bitmap correctly.
2012 */
2013 ASSERT(bitmap_weight(rbio->error_bitmap, rbio->nr_sectors));
2014 bio_list_init(&bio_list);
2015
2016 /* For recovery, we need to read all sectors including P/Q. */
2017 ret = alloc_rbio_pages(rbio);
2018 if (ret < 0)
2019 goto out;
2020
2021 index_rbio_pages(rbio);
2022
2023 ret = recover_assemble_read_bios(rbio, &bio_list);
2024 if (ret < 0)
2025 goto out;
2026
2027 submit_read_bios(rbio, &bio_list);
2028 wait_event(rbio->io_wait, atomic_read(&rbio->stripes_pending) == 0);
2029
2030 ret = recover_sectors(rbio);
2031
2032out:
2033 while ((bio = bio_list_pop(&bio_list)))
2034 bio_put(bio);
2035
2036 return ret;
2037}
2038
2039static void recover_rbio_work(struct work_struct *work)
2040{
2041 struct btrfs_raid_bio *rbio;
2042 int ret;
2043
2044 rbio = container_of(work, struct btrfs_raid_bio, work);
2045
2046 ret = lock_stripe_add(rbio);
2047 if (ret == 0) {
2048 ret = recover_rbio(rbio);
2049 rbio_orig_end_io(rbio, errno_to_blk_status(ret));
2050 }
2051}
2052
2053static void recover_rbio_work_locked(struct work_struct *work)
2054{
2055 struct btrfs_raid_bio *rbio;
2056 int ret;
2057
2058 rbio = container_of(work, struct btrfs_raid_bio, work);
2059
2060 ret = recover_rbio(rbio);
2061 rbio_orig_end_io(rbio, errno_to_blk_status(ret));
2062}
2063
2064static void set_rbio_raid6_extra_error(struct btrfs_raid_bio *rbio, int mirror_num)
2065{
2066 bool found = false;
2067 int sector_nr;
2068
2069 /*
2070 * This is for RAID6 extra recovery tries, thus mirror number should
2071 * be large than 2.
2072 * Mirror 1 means read from data stripes. Mirror 2 means rebuild using
2073 * RAID5 methods.
2074 */
2075 ASSERT(mirror_num > 2);
2076 for (sector_nr = 0; sector_nr < rbio->stripe_nsectors; sector_nr++) {
2077 int found_errors;
2078 int faila;
2079 int failb;
2080
2081 found_errors = get_rbio_veritical_errors(rbio, sector_nr,
2082 &faila, &failb);
2083 /* This vertical stripe doesn't have errors. */
2084 if (!found_errors)
2085 continue;
2086
2087 /*
2088 * If we found errors, there should be only one error marked
2089 * by previous set_rbio_range_error().
2090 */
2091 ASSERT(found_errors == 1);
2092 found = true;
2093
2094 /* Now select another stripe to mark as error. */
2095 failb = rbio->real_stripes - (mirror_num - 1);
2096 if (failb <= faila)
2097 failb--;
2098
2099 /* Set the extra bit in error bitmap. */
2100 if (failb >= 0)
2101 set_bit(failb * rbio->stripe_nsectors + sector_nr,
2102 rbio->error_bitmap);
2103 }
2104
2105 /* We should found at least one vertical stripe with error.*/
2106 ASSERT(found);
2107}
2108
2109/*
2110 * the main entry point for reads from the higher layers. This
2111 * is really only called when the normal read path had a failure,
2112 * so we assume the bio they send down corresponds to a failed part
2113 * of the drive.
2114 */
2115void raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
2116 int mirror_num)
2117{
2118 struct btrfs_fs_info *fs_info = bioc->fs_info;
2119 struct btrfs_raid_bio *rbio;
2120
2121 rbio = alloc_rbio(fs_info, bioc);
2122 if (IS_ERR(rbio)) {
2123 bio->bi_status = errno_to_blk_status(PTR_ERR(rbio));
2124 bio_endio(bio);
2125 return;
2126 }
2127
2128 rbio->operation = BTRFS_RBIO_READ_REBUILD;
2129 rbio_add_bio(rbio, bio);
2130
2131 set_rbio_range_error(rbio, bio);
2132
2133 /*
2134 * Loop retry:
2135 * for 'mirror == 2', reconstruct from all other stripes.
2136 * for 'mirror_num > 2', select a stripe to fail on every retry.
2137 */
2138 if (mirror_num > 2)
2139 set_rbio_raid6_extra_error(rbio, mirror_num);
2140
2141 start_async_work(rbio, recover_rbio_work);
2142}
2143
2144static void fill_data_csums(struct btrfs_raid_bio *rbio)
2145{
2146 struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
2147 struct btrfs_root *csum_root = btrfs_csum_root(fs_info,
2148 rbio->bioc->raid_map[0]);
2149 const u64 start = rbio->bioc->raid_map[0];
2150 const u32 len = (rbio->nr_data * rbio->stripe_nsectors) <<
2151 fs_info->sectorsize_bits;
2152 int ret;
2153
2154 /* The rbio should not have its csum buffer initialized. */
2155 ASSERT(!rbio->csum_buf && !rbio->csum_bitmap);
2156
2157 /*
2158 * Skip the csum search if:
2159 *
2160 * - The rbio doesn't belong to data block groups
2161 * Then we are doing IO for tree blocks, no need to search csums.
2162 *
2163 * - The rbio belongs to mixed block groups
2164 * This is to avoid deadlock, as we're already holding the full
2165 * stripe lock, if we trigger a metadata read, and it needs to do
2166 * raid56 recovery, we will deadlock.
2167 */
2168 if (!(rbio->bioc->map_type & BTRFS_BLOCK_GROUP_DATA) ||
2169 rbio->bioc->map_type & BTRFS_BLOCK_GROUP_METADATA)
2170 return;
2171
2172 rbio->csum_buf = kzalloc(rbio->nr_data * rbio->stripe_nsectors *
2173 fs_info->csum_size, GFP_NOFS);
2174 rbio->csum_bitmap = bitmap_zalloc(rbio->nr_data * rbio->stripe_nsectors,
2175 GFP_NOFS);
2176 if (!rbio->csum_buf || !rbio->csum_bitmap) {
2177 ret = -ENOMEM;
2178 goto error;
2179 }
2180
2181 ret = btrfs_lookup_csums_bitmap(csum_root, start, start + len - 1,
2182 rbio->csum_buf, rbio->csum_bitmap);
2183 if (ret < 0)
2184 goto error;
2185 if (bitmap_empty(rbio->csum_bitmap, len >> fs_info->sectorsize_bits))
2186 goto no_csum;
2187 return;
2188
2189error:
2190 /*
2191 * We failed to allocate memory or grab the csum, but it's not fatal,
2192 * we can still continue. But better to warn users that RMW is no
2193 * longer safe for this particular sub-stripe write.
2194 */
2195 btrfs_warn_rl(fs_info,
2196"sub-stripe write for full stripe %llu is not safe, failed to get csum: %d",
2197 rbio->bioc->raid_map[0], ret);
2198no_csum:
2199 kfree(rbio->csum_buf);
2200 bitmap_free(rbio->csum_bitmap);
2201 rbio->csum_buf = NULL;
2202 rbio->csum_bitmap = NULL;
2203}
2204
2205static int rmw_read_wait_recover(struct btrfs_raid_bio *rbio)
2206{
2207 struct bio_list bio_list;
2208 struct bio *bio;
2209 int ret;
2210
2211 bio_list_init(&bio_list);
2212
2213 /*
2214 * Fill the data csums we need for data verification. We need to fill
2215 * the csum_bitmap/csum_buf first, as our endio function will try to
2216 * verify the data sectors.
2217 */
2218 fill_data_csums(rbio);
2219
2220 ret = rmw_assemble_read_bios(rbio, &bio_list);
2221 if (ret < 0)
2222 goto out;
2223
2224 submit_read_bios(rbio, &bio_list);
2225 wait_event(rbio->io_wait, atomic_read(&rbio->stripes_pending) == 0);
2226
2227 /*
2228 * We may or may not have any corrupted sectors (including missing dev
2229 * and csum mismatch), just let recover_sectors() to handle them all.
2230 */
2231 ret = recover_sectors(rbio);
2232 return ret;
2233out:
2234 while ((bio = bio_list_pop(&bio_list)))
2235 bio_put(bio);
2236
2237 return ret;
2238}
2239
2240static void raid_wait_write_end_io(struct bio *bio)
2241{
2242 struct btrfs_raid_bio *rbio = bio->bi_private;
2243 blk_status_t err = bio->bi_status;
2244
2245 if (err)
2246 rbio_update_error_bitmap(rbio, bio);
2247 bio_put(bio);
2248 if (atomic_dec_and_test(&rbio->stripes_pending))
2249 wake_up(&rbio->io_wait);
2250}
2251
2252static void submit_write_bios(struct btrfs_raid_bio *rbio,
2253 struct bio_list *bio_list)
2254{
2255 struct bio *bio;
2256
2257 atomic_set(&rbio->stripes_pending, bio_list_size(bio_list));
2258 while ((bio = bio_list_pop(bio_list))) {
2259 bio->bi_end_io = raid_wait_write_end_io;
2260
2261 if (trace_raid56_write_stripe_enabled()) {
2262 struct raid56_bio_trace_info trace_info = { 0 };
2263
2264 bio_get_trace_info(rbio, bio, &trace_info);
2265 trace_raid56_write_stripe(rbio, bio, &trace_info);
2266 }
2267 submit_bio(bio);
2268 }
2269}
2270
2271/*
2272 * To determine if we need to read any sector from the disk.
2273 * Should only be utilized in RMW path, to skip cached rbio.
2274 */
2275static bool need_read_stripe_sectors(struct btrfs_raid_bio *rbio)
2276{
2277 int i;
2278
2279 for (i = 0; i < rbio->nr_data * rbio->stripe_nsectors; i++) {
2280 struct sector_ptr *sector = &rbio->stripe_sectors[i];
2281
2282 /*
2283 * We have a sector which doesn't have page nor uptodate,
2284 * thus this rbio can not be cached one, as cached one must
2285 * have all its data sectors present and uptodate.
2286 */
2287 if (!sector->page || !sector->uptodate)
2288 return true;
2289 }
2290 return false;
2291}
2292
2293static int rmw_rbio(struct btrfs_raid_bio *rbio)
2294{
2295 struct bio_list bio_list;
2296 int sectornr;
2297 int ret = 0;
2298
2299 /*
2300 * Allocate the pages for parity first, as P/Q pages will always be
2301 * needed for both full-stripe and sub-stripe writes.
2302 */
2303 ret = alloc_rbio_parity_pages(rbio);
2304 if (ret < 0)
2305 return ret;
2306
2307 /*
2308 * Either full stripe write, or we have every data sector already
2309 * cached, can go to write path immediately.
2310 */
2311 if (rbio_is_full(rbio) || !need_read_stripe_sectors(rbio))
2312 goto write;
2313
2314 /*
2315 * Now we're doing sub-stripe write, also need all data stripes to do
2316 * the full RMW.
2317 */
2318 ret = alloc_rbio_data_pages(rbio);
2319 if (ret < 0)
2320 return ret;
2321
2322 index_rbio_pages(rbio);
2323
2324 ret = rmw_read_wait_recover(rbio);
2325 if (ret < 0)
2326 return ret;
2327
2328write:
2329 /*
2330 * At this stage we're not allowed to add any new bios to the
2331 * bio list any more, anyone else that wants to change this stripe
2332 * needs to do their own rmw.
2333 */
2334 spin_lock_irq(&rbio->bio_list_lock);
2335 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
2336 spin_unlock_irq(&rbio->bio_list_lock);
2337
2338 bitmap_clear(rbio->error_bitmap, 0, rbio->nr_sectors);
2339
2340 index_rbio_pages(rbio);
2341
2342 /*
2343 * We don't cache full rbios because we're assuming
2344 * the higher layers are unlikely to use this area of
2345 * the disk again soon. If they do use it again,
2346 * hopefully they will send another full bio.
2347 */
2348 if (!rbio_is_full(rbio))
2349 cache_rbio_pages(rbio);
2350 else
2351 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
2352
2353 for (sectornr = 0; sectornr < rbio->stripe_nsectors; sectornr++)
2354 generate_pq_vertical(rbio, sectornr);
2355
2356 bio_list_init(&bio_list);
2357 ret = rmw_assemble_write_bios(rbio, &bio_list);
2358 if (ret < 0)
2359 return ret;
2360
2361 /* We should have at least one bio assembled. */
2362 ASSERT(bio_list_size(&bio_list));
2363 submit_write_bios(rbio, &bio_list);
2364 wait_event(rbio->io_wait, atomic_read(&rbio->stripes_pending) == 0);
2365
2366 /* We may have more errors than our tolerance during the read. */
2367 for (sectornr = 0; sectornr < rbio->stripe_nsectors; sectornr++) {
2368 int found_errors;
2369
2370 found_errors = get_rbio_veritical_errors(rbio, sectornr, NULL, NULL);
2371 if (found_errors > rbio->bioc->max_errors) {
2372 ret = -EIO;
2373 break;
2374 }
2375 }
2376 return ret;
2377}
2378
2379static void rmw_rbio_work(struct work_struct *work)
2380{
2381 struct btrfs_raid_bio *rbio;
2382 int ret;
2383
2384 rbio = container_of(work, struct btrfs_raid_bio, work);
2385
2386 ret = lock_stripe_add(rbio);
2387 if (ret == 0) {
2388 ret = rmw_rbio(rbio);
2389 rbio_orig_end_io(rbio, errno_to_blk_status(ret));
2390 }
2391}
2392
2393static void rmw_rbio_work_locked(struct work_struct *work)
2394{
2395 struct btrfs_raid_bio *rbio;
2396 int ret;
2397
2398 rbio = container_of(work, struct btrfs_raid_bio, work);
2399
2400 ret = rmw_rbio(rbio);
2401 rbio_orig_end_io(rbio, errno_to_blk_status(ret));
2402}
2403
2404/*
2405 * The following code is used to scrub/replace the parity stripe
2406 *
2407 * Caller must have already increased bio_counter for getting @bioc.
2408 *
2409 * Note: We need make sure all the pages that add into the scrub/replace
2410 * raid bio are correct and not be changed during the scrub/replace. That
2411 * is those pages just hold metadata or file data with checksum.
2412 */
2413
2414struct btrfs_raid_bio *raid56_parity_alloc_scrub_rbio(struct bio *bio,
2415 struct btrfs_io_context *bioc,
2416 struct btrfs_device *scrub_dev,
2417 unsigned long *dbitmap, int stripe_nsectors)
2418{
2419 struct btrfs_fs_info *fs_info = bioc->fs_info;
2420 struct btrfs_raid_bio *rbio;
2421 int i;
2422
2423 rbio = alloc_rbio(fs_info, bioc);
2424 if (IS_ERR(rbio))
2425 return NULL;
2426 bio_list_add(&rbio->bio_list, bio);
2427 /*
2428 * This is a special bio which is used to hold the completion handler
2429 * and make the scrub rbio is similar to the other types
2430 */
2431 ASSERT(!bio->bi_iter.bi_size);
2432 rbio->operation = BTRFS_RBIO_PARITY_SCRUB;
2433
2434 /*
2435 * After mapping bioc with BTRFS_MAP_WRITE, parities have been sorted
2436 * to the end position, so this search can start from the first parity
2437 * stripe.
2438 */
2439 for (i = rbio->nr_data; i < rbio->real_stripes; i++) {
2440 if (bioc->stripes[i].dev == scrub_dev) {
2441 rbio->scrubp = i;
2442 break;
2443 }
2444 }
2445 ASSERT(i < rbio->real_stripes);
2446
2447 bitmap_copy(&rbio->dbitmap, dbitmap, stripe_nsectors);
2448 return rbio;
2449}
2450
2451/* Used for both parity scrub and missing. */
2452void raid56_add_scrub_pages(struct btrfs_raid_bio *rbio, struct page *page,
2453 unsigned int pgoff, u64 logical)
2454{
2455 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
2456 int stripe_offset;
2457 int index;
2458
2459 ASSERT(logical >= rbio->bioc->raid_map[0]);
2460 ASSERT(logical + sectorsize <= rbio->bioc->raid_map[0] +
2461 BTRFS_STRIPE_LEN * rbio->nr_data);
2462 stripe_offset = (int)(logical - rbio->bioc->raid_map[0]);
2463 index = stripe_offset / sectorsize;
2464 rbio->bio_sectors[index].page = page;
2465 rbio->bio_sectors[index].pgoff = pgoff;
2466}
2467
2468/*
2469 * We just scrub the parity that we have correct data on the same horizontal,
2470 * so we needn't allocate all pages for all the stripes.
2471 */
2472static int alloc_rbio_essential_pages(struct btrfs_raid_bio *rbio)
2473{
2474 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
2475 int total_sector_nr;
2476
2477 for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
2478 total_sector_nr++) {
2479 struct page *page;
2480 int sectornr = total_sector_nr % rbio->stripe_nsectors;
2481 int index = (total_sector_nr * sectorsize) >> PAGE_SHIFT;
2482
2483 if (!test_bit(sectornr, &rbio->dbitmap))
2484 continue;
2485 if (rbio->stripe_pages[index])
2486 continue;
2487 page = alloc_page(GFP_NOFS);
2488 if (!page)
2489 return -ENOMEM;
2490 rbio->stripe_pages[index] = page;
2491 }
2492 index_stripe_sectors(rbio);
2493 return 0;
2494}
2495
2496static int finish_parity_scrub(struct btrfs_raid_bio *rbio, int need_check)
2497{
2498 struct btrfs_io_context *bioc = rbio->bioc;
2499 const u32 sectorsize = bioc->fs_info->sectorsize;
2500 void **pointers = rbio->finish_pointers;
2501 unsigned long *pbitmap = &rbio->finish_pbitmap;
2502 int nr_data = rbio->nr_data;
2503 int stripe;
2504 int sectornr;
2505 bool has_qstripe;
2506 struct sector_ptr p_sector = { 0 };
2507 struct sector_ptr q_sector = { 0 };
2508 struct bio_list bio_list;
2509 struct bio *bio;
2510 int is_replace = 0;
2511 int ret;
2512
2513 bio_list_init(&bio_list);
2514
2515 if (rbio->real_stripes - rbio->nr_data == 1)
2516 has_qstripe = false;
2517 else if (rbio->real_stripes - rbio->nr_data == 2)
2518 has_qstripe = true;
2519 else
2520 BUG();
2521
2522 if (bioc->num_tgtdevs && bioc->tgtdev_map[rbio->scrubp]) {
2523 is_replace = 1;
2524 bitmap_copy(pbitmap, &rbio->dbitmap, rbio->stripe_nsectors);
2525 }
2526
2527 /*
2528 * Because the higher layers(scrubber) are unlikely to
2529 * use this area of the disk again soon, so don't cache
2530 * it.
2531 */
2532 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
2533
2534 if (!need_check)
2535 goto writeback;
2536
2537 p_sector.page = alloc_page(GFP_NOFS);
2538 if (!p_sector.page)
2539 return -ENOMEM;
2540 p_sector.pgoff = 0;
2541 p_sector.uptodate = 1;
2542
2543 if (has_qstripe) {
2544 /* RAID6, allocate and map temp space for the Q stripe */
2545 q_sector.page = alloc_page(GFP_NOFS);
2546 if (!q_sector.page) {
2547 __free_page(p_sector.page);
2548 p_sector.page = NULL;
2549 return -ENOMEM;
2550 }
2551 q_sector.pgoff = 0;
2552 q_sector.uptodate = 1;
2553 pointers[rbio->real_stripes - 1] = kmap_local_page(q_sector.page);
2554 }
2555
2556 bitmap_clear(rbio->error_bitmap, 0, rbio->nr_sectors);
2557
2558 /* Map the parity stripe just once */
2559 pointers[nr_data] = kmap_local_page(p_sector.page);
2560
2561 for_each_set_bit(sectornr, &rbio->dbitmap, rbio->stripe_nsectors) {
2562 struct sector_ptr *sector;
2563 void *parity;
2564
2565 /* first collect one page from each data stripe */
2566 for (stripe = 0; stripe < nr_data; stripe++) {
2567 sector = sector_in_rbio(rbio, stripe, sectornr, 0);
2568 pointers[stripe] = kmap_local_page(sector->page) +
2569 sector->pgoff;
2570 }
2571
2572 if (has_qstripe) {
2573 /* RAID6, call the library function to fill in our P/Q */
2574 raid6_call.gen_syndrome(rbio->real_stripes, sectorsize,
2575 pointers);
2576 } else {
2577 /* raid5 */
2578 memcpy(pointers[nr_data], pointers[0], sectorsize);
2579 run_xor(pointers + 1, nr_data - 1, sectorsize);
2580 }
2581
2582 /* Check scrubbing parity and repair it */
2583 sector = rbio_stripe_sector(rbio, rbio->scrubp, sectornr);
2584 parity = kmap_local_page(sector->page) + sector->pgoff;
2585 if (memcmp(parity, pointers[rbio->scrubp], sectorsize) != 0)
2586 memcpy(parity, pointers[rbio->scrubp], sectorsize);
2587 else
2588 /* Parity is right, needn't writeback */
2589 bitmap_clear(&rbio->dbitmap, sectornr, 1);
2590 kunmap_local(parity);
2591
2592 for (stripe = nr_data - 1; stripe >= 0; stripe--)
2593 kunmap_local(pointers[stripe]);
2594 }
2595
2596 kunmap_local(pointers[nr_data]);
2597 __free_page(p_sector.page);
2598 p_sector.page = NULL;
2599 if (q_sector.page) {
2600 kunmap_local(pointers[rbio->real_stripes - 1]);
2601 __free_page(q_sector.page);
2602 q_sector.page = NULL;
2603 }
2604
2605writeback:
2606 /*
2607 * time to start writing. Make bios for everything from the
2608 * higher layers (the bio_list in our rbio) and our p/q. Ignore
2609 * everything else.
2610 */
2611 for_each_set_bit(sectornr, &rbio->dbitmap, rbio->stripe_nsectors) {
2612 struct sector_ptr *sector;
2613
2614 sector = rbio_stripe_sector(rbio, rbio->scrubp, sectornr);
2615 ret = rbio_add_io_sector(rbio, &bio_list, sector, rbio->scrubp,
2616 sectornr, REQ_OP_WRITE);
2617 if (ret)
2618 goto cleanup;
2619 }
2620
2621 if (!is_replace)
2622 goto submit_write;
2623
2624 for_each_set_bit(sectornr, pbitmap, rbio->stripe_nsectors) {
2625 struct sector_ptr *sector;
2626
2627 sector = rbio_stripe_sector(rbio, rbio->scrubp, sectornr);
2628 ret = rbio_add_io_sector(rbio, &bio_list, sector,
2629 bioc->tgtdev_map[rbio->scrubp],
2630 sectornr, REQ_OP_WRITE);
2631 if (ret)
2632 goto cleanup;
2633 }
2634
2635submit_write:
2636 submit_write_bios(rbio, &bio_list);
2637 return 0;
2638
2639cleanup:
2640 while ((bio = bio_list_pop(&bio_list)))
2641 bio_put(bio);
2642 return ret;
2643}
2644
2645static inline int is_data_stripe(struct btrfs_raid_bio *rbio, int stripe)
2646{
2647 if (stripe >= 0 && stripe < rbio->nr_data)
2648 return 1;
2649 return 0;
2650}
2651
2652static int recover_scrub_rbio(struct btrfs_raid_bio *rbio)
2653{
2654 void **pointers = NULL;
2655 void **unmap_array = NULL;
2656 int sector_nr;
2657 int ret = 0;
2658
2659 /*
2660 * @pointers array stores the pointer for each sector.
2661 *
2662 * @unmap_array stores copy of pointers that does not get reordered
2663 * during reconstruction so that kunmap_local works.
2664 */
2665 pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
2666 unmap_array = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
2667 if (!pointers || !unmap_array) {
2668 ret = -ENOMEM;
2669 goto out;
2670 }
2671
2672 for (sector_nr = 0; sector_nr < rbio->stripe_nsectors; sector_nr++) {
2673 int dfail = 0, failp = -1;
2674 int faila;
2675 int failb;
2676 int found_errors;
2677
2678 found_errors = get_rbio_veritical_errors(rbio, sector_nr,
2679 &faila, &failb);
2680 if (found_errors > rbio->bioc->max_errors) {
2681 ret = -EIO;
2682 goto out;
2683 }
2684 if (found_errors == 0)
2685 continue;
2686
2687 /* We should have at least one error here. */
2688 ASSERT(faila >= 0 || failb >= 0);
2689
2690 if (is_data_stripe(rbio, faila))
2691 dfail++;
2692 else if (is_parity_stripe(faila))
2693 failp = faila;
2694
2695 if (is_data_stripe(rbio, failb))
2696 dfail++;
2697 else if (is_parity_stripe(failb))
2698 failp = failb;
2699 /*
2700 * Because we can not use a scrubbing parity to repair the
2701 * data, so the capability of the repair is declined. (In the
2702 * case of RAID5, we can not repair anything.)
2703 */
2704 if (dfail > rbio->bioc->max_errors - 1) {
2705 ret = -EIO;
2706 goto out;
2707 }
2708 /*
2709 * If all data is good, only parity is correctly, just repair
2710 * the parity, no need to recover data stripes.
2711 */
2712 if (dfail == 0)
2713 continue;
2714
2715 /*
2716 * Here means we got one corrupted data stripe and one
2717 * corrupted parity on RAID6, if the corrupted parity is
2718 * scrubbing parity, luckily, use the other one to repair the
2719 * data, or we can not repair the data stripe.
2720 */
2721 if (failp != rbio->scrubp) {
2722 ret = -EIO;
2723 goto out;
2724 }
2725
2726 ret = recover_vertical(rbio, sector_nr, pointers, unmap_array);
2727 if (ret < 0)
2728 goto out;
2729 }
2730out:
2731 kfree(pointers);
2732 kfree(unmap_array);
2733 return ret;
2734}
2735
2736static int scrub_assemble_read_bios(struct btrfs_raid_bio *rbio,
2737 struct bio_list *bio_list)
2738{
2739 struct bio *bio;
2740 int total_sector_nr;
2741 int ret = 0;
2742
2743 ASSERT(bio_list_size(bio_list) == 0);
2744
2745 /* Build a list of bios to read all the missing parts. */
2746 for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
2747 total_sector_nr++) {
2748 int sectornr = total_sector_nr % rbio->stripe_nsectors;
2749 int stripe = total_sector_nr / rbio->stripe_nsectors;
2750 struct sector_ptr *sector;
2751
2752 /* No data in the vertical stripe, no need to read. */
2753 if (!test_bit(sectornr, &rbio->dbitmap))
2754 continue;
2755
2756 /*
2757 * We want to find all the sectors missing from the rbio and
2758 * read them from the disk. If sector_in_rbio() finds a sector
2759 * in the bio list we don't need to read it off the stripe.
2760 */
2761 sector = sector_in_rbio(rbio, stripe, sectornr, 1);
2762 if (sector)
2763 continue;
2764
2765 sector = rbio_stripe_sector(rbio, stripe, sectornr);
2766 /*
2767 * The bio cache may have handed us an uptodate sector. If so,
2768 * use it.
2769 */
2770 if (sector->uptodate)
2771 continue;
2772
2773 ret = rbio_add_io_sector(rbio, bio_list, sector, stripe,
2774 sectornr, REQ_OP_READ);
2775 if (ret)
2776 goto error;
2777 }
2778 return 0;
2779error:
2780 while ((bio = bio_list_pop(bio_list)))
2781 bio_put(bio);
2782 return ret;
2783}
2784
2785static int scrub_rbio(struct btrfs_raid_bio *rbio)
2786{
2787 bool need_check = false;
2788 struct bio_list bio_list;
2789 int sector_nr;
2790 int ret;
2791 struct bio *bio;
2792
2793 bio_list_init(&bio_list);
2794
2795 ret = alloc_rbio_essential_pages(rbio);
2796 if (ret)
2797 goto cleanup;
2798
2799 bitmap_clear(rbio->error_bitmap, 0, rbio->nr_sectors);
2800
2801 ret = scrub_assemble_read_bios(rbio, &bio_list);
2802 if (ret < 0)
2803 goto cleanup;
2804
2805 submit_read_bios(rbio, &bio_list);
2806 wait_event(rbio->io_wait, atomic_read(&rbio->stripes_pending) == 0);
2807
2808 /* We may have some failures, recover the failed sectors first. */
2809 ret = recover_scrub_rbio(rbio);
2810 if (ret < 0)
2811 goto cleanup;
2812
2813 /*
2814 * We have every sector properly prepared. Can finish the scrub
2815 * and writeback the good content.
2816 */
2817 ret = finish_parity_scrub(rbio, need_check);
2818 wait_event(rbio->io_wait, atomic_read(&rbio->stripes_pending) == 0);
2819 for (sector_nr = 0; sector_nr < rbio->stripe_nsectors; sector_nr++) {
2820 int found_errors;
2821
2822 found_errors = get_rbio_veritical_errors(rbio, sector_nr, NULL, NULL);
2823 if (found_errors > rbio->bioc->max_errors) {
2824 ret = -EIO;
2825 break;
2826 }
2827 }
2828 return ret;
2829
2830cleanup:
2831 while ((bio = bio_list_pop(&bio_list)))
2832 bio_put(bio);
2833
2834 return ret;
2835}
2836
2837static void scrub_rbio_work_locked(struct work_struct *work)
2838{
2839 struct btrfs_raid_bio *rbio;
2840 int ret;
2841
2842 rbio = container_of(work, struct btrfs_raid_bio, work);
2843 ret = scrub_rbio(rbio);
2844 rbio_orig_end_io(rbio, errno_to_blk_status(ret));
2845}
2846
2847void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio)
2848{
2849 if (!lock_stripe_add(rbio))
2850 start_async_work(rbio, scrub_rbio_work_locked);
2851}
2852
2853/* The following code is used for dev replace of a missing RAID 5/6 device. */
2854
2855struct btrfs_raid_bio *
2856raid56_alloc_missing_rbio(struct bio *bio, struct btrfs_io_context *bioc)
2857{
2858 struct btrfs_fs_info *fs_info = bioc->fs_info;
2859 struct btrfs_raid_bio *rbio;
2860
2861 rbio = alloc_rbio(fs_info, bioc);
2862 if (IS_ERR(rbio))
2863 return NULL;
2864
2865 rbio->operation = BTRFS_RBIO_REBUILD_MISSING;
2866 bio_list_add(&rbio->bio_list, bio);
2867 /*
2868 * This is a special bio which is used to hold the completion handler
2869 * and make the scrub rbio is similar to the other types
2870 */
2871 ASSERT(!bio->bi_iter.bi_size);
2872
2873 set_rbio_range_error(rbio, bio);
2874
2875 return rbio;
2876}
2877
2878void raid56_submit_missing_rbio(struct btrfs_raid_bio *rbio)
2879{
2880 start_async_work(rbio, recover_rbio_work);
2881}
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}