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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2012 Fusion-io All rights reserved.
4 * Copyright (C) 2012 Intel Corp. All rights reserved.
5 */
6
7#include <linux/sched.h>
8#include <linux/bio.h>
9#include <linux/slab.h>
10#include <linux/blkdev.h>
11#include <linux/raid/pq.h>
12#include <linux/hash.h>
13#include <linux/list_sort.h>
14#include <linux/raid/xor.h>
15#include <linux/mm.h>
16#include "ctree.h"
17#include "disk-io.h"
18#include "volumes.h"
19#include "raid56.h"
20#include "async-thread.h"
21
22/* set when additional merges to this rbio are not allowed */
23#define RBIO_RMW_LOCKED_BIT 1
24
25/*
26 * set when this rbio is sitting in the hash, but it is just a cache
27 * of past RMW
28 */
29#define RBIO_CACHE_BIT 2
30
31/*
32 * set when it is safe to trust the stripe_pages for caching
33 */
34#define RBIO_CACHE_READY_BIT 3
35
36#define RBIO_CACHE_SIZE 1024
37
38#define BTRFS_STRIPE_HASH_TABLE_BITS 11
39
40/* Used by the raid56 code to lock stripes for read/modify/write */
41struct btrfs_stripe_hash {
42 struct list_head hash_list;
43 spinlock_t lock;
44};
45
46/* Used by the raid56 code to lock stripes for read/modify/write */
47struct btrfs_stripe_hash_table {
48 struct list_head stripe_cache;
49 spinlock_t cache_lock;
50 int cache_size;
51 struct btrfs_stripe_hash table[];
52};
53
54enum btrfs_rbio_ops {
55 BTRFS_RBIO_WRITE,
56 BTRFS_RBIO_READ_REBUILD,
57 BTRFS_RBIO_PARITY_SCRUB,
58 BTRFS_RBIO_REBUILD_MISSING,
59};
60
61struct btrfs_raid_bio {
62 struct btrfs_fs_info *fs_info;
63 struct btrfs_bio *bbio;
64
65 /* while we're doing rmw on a stripe
66 * we put it into a hash table so we can
67 * lock the stripe and merge more rbios
68 * into it.
69 */
70 struct list_head hash_list;
71
72 /*
73 * LRU list for the stripe cache
74 */
75 struct list_head stripe_cache;
76
77 /*
78 * for scheduling work in the helper threads
79 */
80 struct btrfs_work work;
81
82 /*
83 * bio list and bio_list_lock are used
84 * to add more bios into the stripe
85 * in hopes of avoiding the full rmw
86 */
87 struct bio_list bio_list;
88 spinlock_t bio_list_lock;
89
90 /* also protected by the bio_list_lock, the
91 * plug list is used by the plugging code
92 * to collect partial bios while plugged. The
93 * stripe locking code also uses it to hand off
94 * the stripe lock to the next pending IO
95 */
96 struct list_head plug_list;
97
98 /*
99 * flags that tell us if it is safe to
100 * merge with this bio
101 */
102 unsigned long flags;
103
104 /* size of each individual stripe on disk */
105 int stripe_len;
106
107 /* number of data stripes (no p/q) */
108 int nr_data;
109
110 int real_stripes;
111
112 int stripe_npages;
113 /*
114 * set if we're doing a parity rebuild
115 * for a read from higher up, which is handled
116 * differently from a parity rebuild as part of
117 * rmw
118 */
119 enum btrfs_rbio_ops operation;
120
121 /* first bad stripe */
122 int faila;
123
124 /* second bad stripe (for raid6 use) */
125 int failb;
126
127 int scrubp;
128 /*
129 * number of pages needed to represent the full
130 * stripe
131 */
132 int nr_pages;
133
134 /*
135 * size of all the bios in the bio_list. This
136 * helps us decide if the rbio maps to a full
137 * stripe or not
138 */
139 int bio_list_bytes;
140
141 int generic_bio_cnt;
142
143 refcount_t refs;
144
145 atomic_t stripes_pending;
146
147 atomic_t error;
148 /*
149 * these are two arrays of pointers. We allocate the
150 * rbio big enough to hold them both and setup their
151 * locations when the rbio is allocated
152 */
153
154 /* pointers to pages that we allocated for
155 * reading/writing stripes directly from the disk (including P/Q)
156 */
157 struct page **stripe_pages;
158
159 /*
160 * pointers to the pages in the bio_list. Stored
161 * here for faster lookup
162 */
163 struct page **bio_pages;
164
165 /*
166 * bitmap to record which horizontal stripe has data
167 */
168 unsigned long *dbitmap;
169
170 /* allocated with real_stripes-many pointers for finish_*() calls */
171 void **finish_pointers;
172
173 /* allocated with stripe_npages-many bits for finish_*() calls */
174 unsigned long *finish_pbitmap;
175};
176
177static int __raid56_parity_recover(struct btrfs_raid_bio *rbio);
178static noinline void finish_rmw(struct btrfs_raid_bio *rbio);
179static void rmw_work(struct btrfs_work *work);
180static void read_rebuild_work(struct btrfs_work *work);
181static int fail_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio);
182static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed);
183static void __free_raid_bio(struct btrfs_raid_bio *rbio);
184static void index_rbio_pages(struct btrfs_raid_bio *rbio);
185static int alloc_rbio_pages(struct btrfs_raid_bio *rbio);
186
187static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
188 int need_check);
189static void scrub_parity_work(struct btrfs_work *work);
190
191static void start_async_work(struct btrfs_raid_bio *rbio, btrfs_func_t work_func)
192{
193 btrfs_init_work(&rbio->work, btrfs_rmw_helper, work_func, NULL, NULL);
194 btrfs_queue_work(rbio->fs_info->rmw_workers, &rbio->work);
195}
196
197/*
198 * the stripe hash table is used for locking, and to collect
199 * bios in hopes of making a full stripe
200 */
201int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info)
202{
203 struct btrfs_stripe_hash_table *table;
204 struct btrfs_stripe_hash_table *x;
205 struct btrfs_stripe_hash *cur;
206 struct btrfs_stripe_hash *h;
207 int num_entries = 1 << BTRFS_STRIPE_HASH_TABLE_BITS;
208 int i;
209 int table_size;
210
211 if (info->stripe_hash_table)
212 return 0;
213
214 /*
215 * The table is large, starting with order 4 and can go as high as
216 * order 7 in case lock debugging is turned on.
217 *
218 * Try harder to allocate and fallback to vmalloc to lower the chance
219 * of a failing mount.
220 */
221 table_size = sizeof(*table) + sizeof(*h) * num_entries;
222 table = kvzalloc(table_size, GFP_KERNEL);
223 if (!table)
224 return -ENOMEM;
225
226 spin_lock_init(&table->cache_lock);
227 INIT_LIST_HEAD(&table->stripe_cache);
228
229 h = table->table;
230
231 for (i = 0; i < num_entries; i++) {
232 cur = h + i;
233 INIT_LIST_HEAD(&cur->hash_list);
234 spin_lock_init(&cur->lock);
235 }
236
237 x = cmpxchg(&info->stripe_hash_table, NULL, table);
238 if (x)
239 kvfree(x);
240 return 0;
241}
242
243/*
244 * caching an rbio means to copy anything from the
245 * bio_pages array into the stripe_pages array. We
246 * use the page uptodate bit in the stripe cache array
247 * to indicate if it has valid data
248 *
249 * once the caching is done, we set the cache ready
250 * bit.
251 */
252static void cache_rbio_pages(struct btrfs_raid_bio *rbio)
253{
254 int i;
255 char *s;
256 char *d;
257 int ret;
258
259 ret = alloc_rbio_pages(rbio);
260 if (ret)
261 return;
262
263 for (i = 0; i < rbio->nr_pages; i++) {
264 if (!rbio->bio_pages[i])
265 continue;
266
267 s = kmap(rbio->bio_pages[i]);
268 d = kmap(rbio->stripe_pages[i]);
269
270 copy_page(d, s);
271
272 kunmap(rbio->bio_pages[i]);
273 kunmap(rbio->stripe_pages[i]);
274 SetPageUptodate(rbio->stripe_pages[i]);
275 }
276 set_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
277}
278
279/*
280 * we hash on the first logical address of the stripe
281 */
282static int rbio_bucket(struct btrfs_raid_bio *rbio)
283{
284 u64 num = rbio->bbio->raid_map[0];
285
286 /*
287 * we shift down quite a bit. We're using byte
288 * addressing, and most of the lower bits are zeros.
289 * This tends to upset hash_64, and it consistently
290 * returns just one or two different values.
291 *
292 * shifting off the lower bits fixes things.
293 */
294 return hash_64(num >> 16, BTRFS_STRIPE_HASH_TABLE_BITS);
295}
296
297/*
298 * stealing an rbio means taking all the uptodate pages from the stripe
299 * array in the source rbio and putting them into the destination rbio
300 */
301static void steal_rbio(struct btrfs_raid_bio *src, struct btrfs_raid_bio *dest)
302{
303 int i;
304 struct page *s;
305 struct page *d;
306
307 if (!test_bit(RBIO_CACHE_READY_BIT, &src->flags))
308 return;
309
310 for (i = 0; i < dest->nr_pages; i++) {
311 s = src->stripe_pages[i];
312 if (!s || !PageUptodate(s)) {
313 continue;
314 }
315
316 d = dest->stripe_pages[i];
317 if (d)
318 __free_page(d);
319
320 dest->stripe_pages[i] = s;
321 src->stripe_pages[i] = NULL;
322 }
323}
324
325/*
326 * merging means we take the bio_list from the victim and
327 * splice it into the destination. The victim should
328 * be discarded afterwards.
329 *
330 * must be called with dest->rbio_list_lock held
331 */
332static void merge_rbio(struct btrfs_raid_bio *dest,
333 struct btrfs_raid_bio *victim)
334{
335 bio_list_merge(&dest->bio_list, &victim->bio_list);
336 dest->bio_list_bytes += victim->bio_list_bytes;
337 dest->generic_bio_cnt += victim->generic_bio_cnt;
338 bio_list_init(&victim->bio_list);
339}
340
341/*
342 * used to prune items that are in the cache. The caller
343 * must hold the hash table lock.
344 */
345static void __remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
346{
347 int bucket = rbio_bucket(rbio);
348 struct btrfs_stripe_hash_table *table;
349 struct btrfs_stripe_hash *h;
350 int freeit = 0;
351
352 /*
353 * check the bit again under the hash table lock.
354 */
355 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
356 return;
357
358 table = rbio->fs_info->stripe_hash_table;
359 h = table->table + bucket;
360
361 /* hold the lock for the bucket because we may be
362 * removing it from the hash table
363 */
364 spin_lock(&h->lock);
365
366 /*
367 * hold the lock for the bio list because we need
368 * to make sure the bio list is empty
369 */
370 spin_lock(&rbio->bio_list_lock);
371
372 if (test_and_clear_bit(RBIO_CACHE_BIT, &rbio->flags)) {
373 list_del_init(&rbio->stripe_cache);
374 table->cache_size -= 1;
375 freeit = 1;
376
377 /* if the bio list isn't empty, this rbio is
378 * still involved in an IO. We take it out
379 * of the cache list, and drop the ref that
380 * was held for the list.
381 *
382 * If the bio_list was empty, we also remove
383 * the rbio from the hash_table, and drop
384 * the corresponding ref
385 */
386 if (bio_list_empty(&rbio->bio_list)) {
387 if (!list_empty(&rbio->hash_list)) {
388 list_del_init(&rbio->hash_list);
389 refcount_dec(&rbio->refs);
390 BUG_ON(!list_empty(&rbio->plug_list));
391 }
392 }
393 }
394
395 spin_unlock(&rbio->bio_list_lock);
396 spin_unlock(&h->lock);
397
398 if (freeit)
399 __free_raid_bio(rbio);
400}
401
402/*
403 * prune a given rbio from the cache
404 */
405static void remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
406{
407 struct btrfs_stripe_hash_table *table;
408 unsigned long flags;
409
410 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
411 return;
412
413 table = rbio->fs_info->stripe_hash_table;
414
415 spin_lock_irqsave(&table->cache_lock, flags);
416 __remove_rbio_from_cache(rbio);
417 spin_unlock_irqrestore(&table->cache_lock, flags);
418}
419
420/*
421 * remove everything in the cache
422 */
423static void btrfs_clear_rbio_cache(struct btrfs_fs_info *info)
424{
425 struct btrfs_stripe_hash_table *table;
426 unsigned long flags;
427 struct btrfs_raid_bio *rbio;
428
429 table = info->stripe_hash_table;
430
431 spin_lock_irqsave(&table->cache_lock, flags);
432 while (!list_empty(&table->stripe_cache)) {
433 rbio = list_entry(table->stripe_cache.next,
434 struct btrfs_raid_bio,
435 stripe_cache);
436 __remove_rbio_from_cache(rbio);
437 }
438 spin_unlock_irqrestore(&table->cache_lock, flags);
439}
440
441/*
442 * remove all cached entries and free the hash table
443 * used by unmount
444 */
445void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info)
446{
447 if (!info->stripe_hash_table)
448 return;
449 btrfs_clear_rbio_cache(info);
450 kvfree(info->stripe_hash_table);
451 info->stripe_hash_table = NULL;
452}
453
454/*
455 * insert an rbio into the stripe cache. It
456 * must have already been prepared by calling
457 * cache_rbio_pages
458 *
459 * If this rbio was already cached, it gets
460 * moved to the front of the lru.
461 *
462 * If the size of the rbio cache is too big, we
463 * prune an item.
464 */
465static void cache_rbio(struct btrfs_raid_bio *rbio)
466{
467 struct btrfs_stripe_hash_table *table;
468 unsigned long flags;
469
470 if (!test_bit(RBIO_CACHE_READY_BIT, &rbio->flags))
471 return;
472
473 table = rbio->fs_info->stripe_hash_table;
474
475 spin_lock_irqsave(&table->cache_lock, flags);
476 spin_lock(&rbio->bio_list_lock);
477
478 /* bump our ref if we were not in the list before */
479 if (!test_and_set_bit(RBIO_CACHE_BIT, &rbio->flags))
480 refcount_inc(&rbio->refs);
481
482 if (!list_empty(&rbio->stripe_cache)){
483 list_move(&rbio->stripe_cache, &table->stripe_cache);
484 } else {
485 list_add(&rbio->stripe_cache, &table->stripe_cache);
486 table->cache_size += 1;
487 }
488
489 spin_unlock(&rbio->bio_list_lock);
490
491 if (table->cache_size > RBIO_CACHE_SIZE) {
492 struct btrfs_raid_bio *found;
493
494 found = list_entry(table->stripe_cache.prev,
495 struct btrfs_raid_bio,
496 stripe_cache);
497
498 if (found != rbio)
499 __remove_rbio_from_cache(found);
500 }
501
502 spin_unlock_irqrestore(&table->cache_lock, flags);
503}
504
505/*
506 * helper function to run the xor_blocks api. It is only
507 * able to do MAX_XOR_BLOCKS at a time, so we need to
508 * loop through.
509 */
510static void run_xor(void **pages, int src_cnt, ssize_t len)
511{
512 int src_off = 0;
513 int xor_src_cnt = 0;
514 void *dest = pages[src_cnt];
515
516 while(src_cnt > 0) {
517 xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS);
518 xor_blocks(xor_src_cnt, len, dest, pages + src_off);
519
520 src_cnt -= xor_src_cnt;
521 src_off += xor_src_cnt;
522 }
523}
524
525/*
526 * Returns true if the bio list inside this rbio covers an entire stripe (no
527 * rmw required).
528 */
529static int rbio_is_full(struct btrfs_raid_bio *rbio)
530{
531 unsigned long flags;
532 unsigned long size = rbio->bio_list_bytes;
533 int ret = 1;
534
535 spin_lock_irqsave(&rbio->bio_list_lock, flags);
536 if (size != rbio->nr_data * rbio->stripe_len)
537 ret = 0;
538 BUG_ON(size > rbio->nr_data * rbio->stripe_len);
539 spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
540
541 return ret;
542}
543
544/*
545 * returns 1 if it is safe to merge two rbios together.
546 * The merging is safe if the two rbios correspond to
547 * the same stripe and if they are both going in the same
548 * direction (read vs write), and if neither one is
549 * locked for final IO
550 *
551 * The caller is responsible for locking such that
552 * rmw_locked is safe to test
553 */
554static int rbio_can_merge(struct btrfs_raid_bio *last,
555 struct btrfs_raid_bio *cur)
556{
557 if (test_bit(RBIO_RMW_LOCKED_BIT, &last->flags) ||
558 test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags))
559 return 0;
560
561 /*
562 * we can't merge with cached rbios, since the
563 * idea is that when we merge the destination
564 * rbio is going to run our IO for us. We can
565 * steal from cached rbios though, other functions
566 * handle that.
567 */
568 if (test_bit(RBIO_CACHE_BIT, &last->flags) ||
569 test_bit(RBIO_CACHE_BIT, &cur->flags))
570 return 0;
571
572 if (last->bbio->raid_map[0] !=
573 cur->bbio->raid_map[0])
574 return 0;
575
576 /* we can't merge with different operations */
577 if (last->operation != cur->operation)
578 return 0;
579 /*
580 * We've need read the full stripe from the drive.
581 * check and repair the parity and write the new results.
582 *
583 * We're not allowed to add any new bios to the
584 * bio list here, anyone else that wants to
585 * change this stripe needs to do their own rmw.
586 */
587 if (last->operation == BTRFS_RBIO_PARITY_SCRUB)
588 return 0;
589
590 if (last->operation == BTRFS_RBIO_REBUILD_MISSING)
591 return 0;
592
593 if (last->operation == BTRFS_RBIO_READ_REBUILD) {
594 int fa = last->faila;
595 int fb = last->failb;
596 int cur_fa = cur->faila;
597 int cur_fb = cur->failb;
598
599 if (last->faila >= last->failb) {
600 fa = last->failb;
601 fb = last->faila;
602 }
603
604 if (cur->faila >= cur->failb) {
605 cur_fa = cur->failb;
606 cur_fb = cur->faila;
607 }
608
609 if (fa != cur_fa || fb != cur_fb)
610 return 0;
611 }
612 return 1;
613}
614
615static int rbio_stripe_page_index(struct btrfs_raid_bio *rbio, int stripe,
616 int index)
617{
618 return stripe * rbio->stripe_npages + index;
619}
620
621/*
622 * these are just the pages from the rbio array, not from anything
623 * the FS sent down to us
624 */
625static struct page *rbio_stripe_page(struct btrfs_raid_bio *rbio, int stripe,
626 int index)
627{
628 return rbio->stripe_pages[rbio_stripe_page_index(rbio, stripe, index)];
629}
630
631/*
632 * helper to index into the pstripe
633 */
634static struct page *rbio_pstripe_page(struct btrfs_raid_bio *rbio, int index)
635{
636 return rbio_stripe_page(rbio, rbio->nr_data, index);
637}
638
639/*
640 * helper to index into the qstripe, returns null
641 * if there is no qstripe
642 */
643static struct page *rbio_qstripe_page(struct btrfs_raid_bio *rbio, int index)
644{
645 if (rbio->nr_data + 1 == rbio->real_stripes)
646 return NULL;
647 return rbio_stripe_page(rbio, rbio->nr_data + 1, index);
648}
649
650/*
651 * The first stripe in the table for a logical address
652 * has the lock. rbios are added in one of three ways:
653 *
654 * 1) Nobody has the stripe locked yet. The rbio is given
655 * the lock and 0 is returned. The caller must start the IO
656 * themselves.
657 *
658 * 2) Someone has the stripe locked, but we're able to merge
659 * with the lock owner. The rbio is freed and the IO will
660 * start automatically along with the existing rbio. 1 is returned.
661 *
662 * 3) Someone has the stripe locked, but we're not able to merge.
663 * The rbio is added to the lock owner's plug list, or merged into
664 * an rbio already on the plug list. When the lock owner unlocks,
665 * the next rbio on the list is run and the IO is started automatically.
666 * 1 is returned
667 *
668 * If we return 0, the caller still owns the rbio and must continue with
669 * IO submission. If we return 1, the caller must assume the rbio has
670 * already been freed.
671 */
672static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
673{
674 int bucket = rbio_bucket(rbio);
675 struct btrfs_stripe_hash *h = rbio->fs_info->stripe_hash_table->table + bucket;
676 struct btrfs_raid_bio *cur;
677 struct btrfs_raid_bio *pending;
678 unsigned long flags;
679 struct btrfs_raid_bio *freeit = NULL;
680 struct btrfs_raid_bio *cache_drop = NULL;
681 int ret = 0;
682
683 spin_lock_irqsave(&h->lock, flags);
684 list_for_each_entry(cur, &h->hash_list, hash_list) {
685 if (cur->bbio->raid_map[0] == rbio->bbio->raid_map[0]) {
686 spin_lock(&cur->bio_list_lock);
687
688 /* can we steal this cached rbio's pages? */
689 if (bio_list_empty(&cur->bio_list) &&
690 list_empty(&cur->plug_list) &&
691 test_bit(RBIO_CACHE_BIT, &cur->flags) &&
692 !test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) {
693 list_del_init(&cur->hash_list);
694 refcount_dec(&cur->refs);
695
696 steal_rbio(cur, rbio);
697 cache_drop = cur;
698 spin_unlock(&cur->bio_list_lock);
699
700 goto lockit;
701 }
702
703 /* can we merge into the lock owner? */
704 if (rbio_can_merge(cur, rbio)) {
705 merge_rbio(cur, rbio);
706 spin_unlock(&cur->bio_list_lock);
707 freeit = rbio;
708 ret = 1;
709 goto out;
710 }
711
712
713 /*
714 * we couldn't merge with the running
715 * rbio, see if we can merge with the
716 * pending ones. We don't have to
717 * check for rmw_locked because there
718 * is no way they are inside finish_rmw
719 * right now
720 */
721 list_for_each_entry(pending, &cur->plug_list,
722 plug_list) {
723 if (rbio_can_merge(pending, rbio)) {
724 merge_rbio(pending, rbio);
725 spin_unlock(&cur->bio_list_lock);
726 freeit = rbio;
727 ret = 1;
728 goto out;
729 }
730 }
731
732 /* no merging, put us on the tail of the plug list,
733 * our rbio will be started with the currently
734 * running rbio unlocks
735 */
736 list_add_tail(&rbio->plug_list, &cur->plug_list);
737 spin_unlock(&cur->bio_list_lock);
738 ret = 1;
739 goto out;
740 }
741 }
742lockit:
743 refcount_inc(&rbio->refs);
744 list_add(&rbio->hash_list, &h->hash_list);
745out:
746 spin_unlock_irqrestore(&h->lock, flags);
747 if (cache_drop)
748 remove_rbio_from_cache(cache_drop);
749 if (freeit)
750 __free_raid_bio(freeit);
751 return ret;
752}
753
754/*
755 * called as rmw or parity rebuild is completed. If the plug list has more
756 * rbios waiting for this stripe, the next one on the list will be started
757 */
758static noinline void unlock_stripe(struct btrfs_raid_bio *rbio)
759{
760 int bucket;
761 struct btrfs_stripe_hash *h;
762 unsigned long flags;
763 int keep_cache = 0;
764
765 bucket = rbio_bucket(rbio);
766 h = rbio->fs_info->stripe_hash_table->table + bucket;
767
768 if (list_empty(&rbio->plug_list))
769 cache_rbio(rbio);
770
771 spin_lock_irqsave(&h->lock, flags);
772 spin_lock(&rbio->bio_list_lock);
773
774 if (!list_empty(&rbio->hash_list)) {
775 /*
776 * if we're still cached and there is no other IO
777 * to perform, just leave this rbio here for others
778 * to steal from later
779 */
780 if (list_empty(&rbio->plug_list) &&
781 test_bit(RBIO_CACHE_BIT, &rbio->flags)) {
782 keep_cache = 1;
783 clear_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
784 BUG_ON(!bio_list_empty(&rbio->bio_list));
785 goto done;
786 }
787
788 list_del_init(&rbio->hash_list);
789 refcount_dec(&rbio->refs);
790
791 /*
792 * we use the plug list to hold all the rbios
793 * waiting for the chance to lock this stripe.
794 * hand the lock over to one of them.
795 */
796 if (!list_empty(&rbio->plug_list)) {
797 struct btrfs_raid_bio *next;
798 struct list_head *head = rbio->plug_list.next;
799
800 next = list_entry(head, struct btrfs_raid_bio,
801 plug_list);
802
803 list_del_init(&rbio->plug_list);
804
805 list_add(&next->hash_list, &h->hash_list);
806 refcount_inc(&next->refs);
807 spin_unlock(&rbio->bio_list_lock);
808 spin_unlock_irqrestore(&h->lock, flags);
809
810 if (next->operation == BTRFS_RBIO_READ_REBUILD)
811 start_async_work(next, read_rebuild_work);
812 else if (next->operation == BTRFS_RBIO_REBUILD_MISSING) {
813 steal_rbio(rbio, next);
814 start_async_work(next, read_rebuild_work);
815 } else if (next->operation == BTRFS_RBIO_WRITE) {
816 steal_rbio(rbio, next);
817 start_async_work(next, rmw_work);
818 } else if (next->operation == BTRFS_RBIO_PARITY_SCRUB) {
819 steal_rbio(rbio, next);
820 start_async_work(next, scrub_parity_work);
821 }
822
823 goto done_nolock;
824 }
825 }
826done:
827 spin_unlock(&rbio->bio_list_lock);
828 spin_unlock_irqrestore(&h->lock, flags);
829
830done_nolock:
831 if (!keep_cache)
832 remove_rbio_from_cache(rbio);
833}
834
835static void __free_raid_bio(struct btrfs_raid_bio *rbio)
836{
837 int i;
838
839 if (!refcount_dec_and_test(&rbio->refs))
840 return;
841
842 WARN_ON(!list_empty(&rbio->stripe_cache));
843 WARN_ON(!list_empty(&rbio->hash_list));
844 WARN_ON(!bio_list_empty(&rbio->bio_list));
845
846 for (i = 0; i < rbio->nr_pages; i++) {
847 if (rbio->stripe_pages[i]) {
848 __free_page(rbio->stripe_pages[i]);
849 rbio->stripe_pages[i] = NULL;
850 }
851 }
852
853 btrfs_put_bbio(rbio->bbio);
854 kfree(rbio);
855}
856
857static void rbio_endio_bio_list(struct bio *cur, blk_status_t err)
858{
859 struct bio *next;
860
861 while (cur) {
862 next = cur->bi_next;
863 cur->bi_next = NULL;
864 cur->bi_status = err;
865 bio_endio(cur);
866 cur = next;
867 }
868}
869
870/*
871 * this frees the rbio and runs through all the bios in the
872 * bio_list and calls end_io on them
873 */
874static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, blk_status_t err)
875{
876 struct bio *cur = bio_list_get(&rbio->bio_list);
877 struct bio *extra;
878
879 if (rbio->generic_bio_cnt)
880 btrfs_bio_counter_sub(rbio->fs_info, rbio->generic_bio_cnt);
881
882 /*
883 * At this moment, rbio->bio_list is empty, however since rbio does not
884 * always have RBIO_RMW_LOCKED_BIT set and rbio is still linked on the
885 * hash list, rbio may be merged with others so that rbio->bio_list
886 * becomes non-empty.
887 * Once unlock_stripe() is done, rbio->bio_list will not be updated any
888 * more and we can call bio_endio() on all queued bios.
889 */
890 unlock_stripe(rbio);
891 extra = bio_list_get(&rbio->bio_list);
892 __free_raid_bio(rbio);
893
894 rbio_endio_bio_list(cur, err);
895 if (extra)
896 rbio_endio_bio_list(extra, err);
897}
898
899/*
900 * end io function used by finish_rmw. When we finally
901 * get here, we've written a full stripe
902 */
903static void raid_write_end_io(struct bio *bio)
904{
905 struct btrfs_raid_bio *rbio = bio->bi_private;
906 blk_status_t err = bio->bi_status;
907 int max_errors;
908
909 if (err)
910 fail_bio_stripe(rbio, bio);
911
912 bio_put(bio);
913
914 if (!atomic_dec_and_test(&rbio->stripes_pending))
915 return;
916
917 err = BLK_STS_OK;
918
919 /* OK, we have read all the stripes we need to. */
920 max_errors = (rbio->operation == BTRFS_RBIO_PARITY_SCRUB) ?
921 0 : rbio->bbio->max_errors;
922 if (atomic_read(&rbio->error) > max_errors)
923 err = BLK_STS_IOERR;
924
925 rbio_orig_end_io(rbio, err);
926}
927
928/*
929 * the read/modify/write code wants to use the original bio for
930 * any pages it included, and then use the rbio for everything
931 * else. This function decides if a given index (stripe number)
932 * and page number in that stripe fall inside the original bio
933 * or the rbio.
934 *
935 * if you set bio_list_only, you'll get a NULL back for any ranges
936 * that are outside the bio_list
937 *
938 * This doesn't take any refs on anything, you get a bare page pointer
939 * and the caller must bump refs as required.
940 *
941 * You must call index_rbio_pages once before you can trust
942 * the answers from this function.
943 */
944static struct page *page_in_rbio(struct btrfs_raid_bio *rbio,
945 int index, int pagenr, int bio_list_only)
946{
947 int chunk_page;
948 struct page *p = NULL;
949
950 chunk_page = index * (rbio->stripe_len >> PAGE_SHIFT) + pagenr;
951
952 spin_lock_irq(&rbio->bio_list_lock);
953 p = rbio->bio_pages[chunk_page];
954 spin_unlock_irq(&rbio->bio_list_lock);
955
956 if (p || bio_list_only)
957 return p;
958
959 return rbio->stripe_pages[chunk_page];
960}
961
962/*
963 * number of pages we need for the entire stripe across all the
964 * drives
965 */
966static unsigned long rbio_nr_pages(unsigned long stripe_len, int nr_stripes)
967{
968 return DIV_ROUND_UP(stripe_len, PAGE_SIZE) * nr_stripes;
969}
970
971/*
972 * allocation and initial setup for the btrfs_raid_bio. Not
973 * this does not allocate any pages for rbio->pages.
974 */
975static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info,
976 struct btrfs_bio *bbio,
977 u64 stripe_len)
978{
979 struct btrfs_raid_bio *rbio;
980 int nr_data = 0;
981 int real_stripes = bbio->num_stripes - bbio->num_tgtdevs;
982 int num_pages = rbio_nr_pages(stripe_len, real_stripes);
983 int stripe_npages = DIV_ROUND_UP(stripe_len, PAGE_SIZE);
984 void *p;
985
986 rbio = kzalloc(sizeof(*rbio) +
987 sizeof(*rbio->stripe_pages) * num_pages +
988 sizeof(*rbio->bio_pages) * num_pages +
989 sizeof(*rbio->finish_pointers) * real_stripes +
990 sizeof(*rbio->dbitmap) * BITS_TO_LONGS(stripe_npages) +
991 sizeof(*rbio->finish_pbitmap) *
992 BITS_TO_LONGS(stripe_npages),
993 GFP_NOFS);
994 if (!rbio)
995 return ERR_PTR(-ENOMEM);
996
997 bio_list_init(&rbio->bio_list);
998 INIT_LIST_HEAD(&rbio->plug_list);
999 spin_lock_init(&rbio->bio_list_lock);
1000 INIT_LIST_HEAD(&rbio->stripe_cache);
1001 INIT_LIST_HEAD(&rbio->hash_list);
1002 rbio->bbio = bbio;
1003 rbio->fs_info = fs_info;
1004 rbio->stripe_len = stripe_len;
1005 rbio->nr_pages = num_pages;
1006 rbio->real_stripes = real_stripes;
1007 rbio->stripe_npages = stripe_npages;
1008 rbio->faila = -1;
1009 rbio->failb = -1;
1010 refcount_set(&rbio->refs, 1);
1011 atomic_set(&rbio->error, 0);
1012 atomic_set(&rbio->stripes_pending, 0);
1013
1014 /*
1015 * the stripe_pages, bio_pages, etc arrays point to the extra
1016 * memory we allocated past the end of the rbio
1017 */
1018 p = rbio + 1;
1019#define CONSUME_ALLOC(ptr, count) do { \
1020 ptr = p; \
1021 p = (unsigned char *)p + sizeof(*(ptr)) * (count); \
1022 } while (0)
1023 CONSUME_ALLOC(rbio->stripe_pages, num_pages);
1024 CONSUME_ALLOC(rbio->bio_pages, num_pages);
1025 CONSUME_ALLOC(rbio->finish_pointers, real_stripes);
1026 CONSUME_ALLOC(rbio->dbitmap, BITS_TO_LONGS(stripe_npages));
1027 CONSUME_ALLOC(rbio->finish_pbitmap, BITS_TO_LONGS(stripe_npages));
1028#undef CONSUME_ALLOC
1029
1030 if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID5)
1031 nr_data = real_stripes - 1;
1032 else if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID6)
1033 nr_data = real_stripes - 2;
1034 else
1035 BUG();
1036
1037 rbio->nr_data = nr_data;
1038 return rbio;
1039}
1040
1041/* allocate pages for all the stripes in the bio, including parity */
1042static int alloc_rbio_pages(struct btrfs_raid_bio *rbio)
1043{
1044 int i;
1045 struct page *page;
1046
1047 for (i = 0; i < rbio->nr_pages; i++) {
1048 if (rbio->stripe_pages[i])
1049 continue;
1050 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1051 if (!page)
1052 return -ENOMEM;
1053 rbio->stripe_pages[i] = page;
1054 }
1055 return 0;
1056}
1057
1058/* only allocate pages for p/q stripes */
1059static int alloc_rbio_parity_pages(struct btrfs_raid_bio *rbio)
1060{
1061 int i;
1062 struct page *page;
1063
1064 i = rbio_stripe_page_index(rbio, rbio->nr_data, 0);
1065
1066 for (; i < rbio->nr_pages; i++) {
1067 if (rbio->stripe_pages[i])
1068 continue;
1069 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1070 if (!page)
1071 return -ENOMEM;
1072 rbio->stripe_pages[i] = page;
1073 }
1074 return 0;
1075}
1076
1077/*
1078 * add a single page from a specific stripe into our list of bios for IO
1079 * this will try to merge into existing bios if possible, and returns
1080 * zero if all went well.
1081 */
1082static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
1083 struct bio_list *bio_list,
1084 struct page *page,
1085 int stripe_nr,
1086 unsigned long page_index,
1087 unsigned long bio_max_len)
1088{
1089 struct bio *last = bio_list->tail;
1090 u64 last_end = 0;
1091 int ret;
1092 struct bio *bio;
1093 struct btrfs_bio_stripe *stripe;
1094 u64 disk_start;
1095
1096 stripe = &rbio->bbio->stripes[stripe_nr];
1097 disk_start = stripe->physical + (page_index << PAGE_SHIFT);
1098
1099 /* if the device is missing, just fail this stripe */
1100 if (!stripe->dev->bdev)
1101 return fail_rbio_index(rbio, stripe_nr);
1102
1103 /* see if we can add this page onto our existing bio */
1104 if (last) {
1105 last_end = (u64)last->bi_iter.bi_sector << 9;
1106 last_end += last->bi_iter.bi_size;
1107
1108 /*
1109 * we can't merge these if they are from different
1110 * devices or if they are not contiguous
1111 */
1112 if (last_end == disk_start && stripe->dev->bdev &&
1113 !last->bi_status &&
1114 last->bi_disk == stripe->dev->bdev->bd_disk &&
1115 last->bi_partno == stripe->dev->bdev->bd_partno) {
1116 ret = bio_add_page(last, page, PAGE_SIZE, 0);
1117 if (ret == PAGE_SIZE)
1118 return 0;
1119 }
1120 }
1121
1122 /* put a new bio on the list */
1123 bio = btrfs_io_bio_alloc(bio_max_len >> PAGE_SHIFT ?: 1);
1124 bio->bi_iter.bi_size = 0;
1125 bio_set_dev(bio, stripe->dev->bdev);
1126 bio->bi_iter.bi_sector = disk_start >> 9;
1127
1128 bio_add_page(bio, page, PAGE_SIZE, 0);
1129 bio_list_add(bio_list, bio);
1130 return 0;
1131}
1132
1133/*
1134 * while we're doing the read/modify/write cycle, we could
1135 * have errors in reading pages off the disk. This checks
1136 * for errors and if we're not able to read the page it'll
1137 * trigger parity reconstruction. The rmw will be finished
1138 * after we've reconstructed the failed stripes
1139 */
1140static void validate_rbio_for_rmw(struct btrfs_raid_bio *rbio)
1141{
1142 if (rbio->faila >= 0 || rbio->failb >= 0) {
1143 BUG_ON(rbio->faila == rbio->real_stripes - 1);
1144 __raid56_parity_recover(rbio);
1145 } else {
1146 finish_rmw(rbio);
1147 }
1148}
1149
1150/*
1151 * helper function to walk our bio list and populate the bio_pages array with
1152 * the result. This seems expensive, but it is faster than constantly
1153 * searching through the bio list as we setup the IO in finish_rmw or stripe
1154 * reconstruction.
1155 *
1156 * This must be called before you trust the answers from page_in_rbio
1157 */
1158static void index_rbio_pages(struct btrfs_raid_bio *rbio)
1159{
1160 struct bio *bio;
1161 u64 start;
1162 unsigned long stripe_offset;
1163 unsigned long page_index;
1164
1165 spin_lock_irq(&rbio->bio_list_lock);
1166 bio_list_for_each(bio, &rbio->bio_list) {
1167 struct bio_vec bvec;
1168 struct bvec_iter iter;
1169 int i = 0;
1170
1171 start = (u64)bio->bi_iter.bi_sector << 9;
1172 stripe_offset = start - rbio->bbio->raid_map[0];
1173 page_index = stripe_offset >> PAGE_SHIFT;
1174
1175 if (bio_flagged(bio, BIO_CLONED))
1176 bio->bi_iter = btrfs_io_bio(bio)->iter;
1177
1178 bio_for_each_segment(bvec, bio, iter) {
1179 rbio->bio_pages[page_index + i] = bvec.bv_page;
1180 i++;
1181 }
1182 }
1183 spin_unlock_irq(&rbio->bio_list_lock);
1184}
1185
1186/*
1187 * this is called from one of two situations. We either
1188 * have a full stripe from the higher layers, or we've read all
1189 * the missing bits off disk.
1190 *
1191 * This will calculate the parity and then send down any
1192 * changed blocks.
1193 */
1194static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
1195{
1196 struct btrfs_bio *bbio = rbio->bbio;
1197 void **pointers = rbio->finish_pointers;
1198 int nr_data = rbio->nr_data;
1199 int stripe;
1200 int pagenr;
1201 int p_stripe = -1;
1202 int q_stripe = -1;
1203 struct bio_list bio_list;
1204 struct bio *bio;
1205 int ret;
1206
1207 bio_list_init(&bio_list);
1208
1209 if (rbio->real_stripes - rbio->nr_data == 1) {
1210 p_stripe = rbio->real_stripes - 1;
1211 } else if (rbio->real_stripes - rbio->nr_data == 2) {
1212 p_stripe = rbio->real_stripes - 2;
1213 q_stripe = rbio->real_stripes - 1;
1214 } else {
1215 BUG();
1216 }
1217
1218 /* at this point we either have a full stripe,
1219 * or we've read the full stripe from the drive.
1220 * recalculate the parity and write the new results.
1221 *
1222 * We're not allowed to add any new bios to the
1223 * bio list here, anyone else that wants to
1224 * change this stripe needs to do their own rmw.
1225 */
1226 spin_lock_irq(&rbio->bio_list_lock);
1227 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1228 spin_unlock_irq(&rbio->bio_list_lock);
1229
1230 atomic_set(&rbio->error, 0);
1231
1232 /*
1233 * now that we've set rmw_locked, run through the
1234 * bio list one last time and map the page pointers
1235 *
1236 * We don't cache full rbios because we're assuming
1237 * the higher layers are unlikely to use this area of
1238 * the disk again soon. If they do use it again,
1239 * hopefully they will send another full bio.
1240 */
1241 index_rbio_pages(rbio);
1242 if (!rbio_is_full(rbio))
1243 cache_rbio_pages(rbio);
1244 else
1245 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
1246
1247 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1248 struct page *p;
1249 /* first collect one page from each data stripe */
1250 for (stripe = 0; stripe < nr_data; stripe++) {
1251 p = page_in_rbio(rbio, stripe, pagenr, 0);
1252 pointers[stripe] = kmap(p);
1253 }
1254
1255 /* then add the parity stripe */
1256 p = rbio_pstripe_page(rbio, pagenr);
1257 SetPageUptodate(p);
1258 pointers[stripe++] = kmap(p);
1259
1260 if (q_stripe != -1) {
1261
1262 /*
1263 * raid6, add the qstripe and call the
1264 * library function to fill in our p/q
1265 */
1266 p = rbio_qstripe_page(rbio, pagenr);
1267 SetPageUptodate(p);
1268 pointers[stripe++] = kmap(p);
1269
1270 raid6_call.gen_syndrome(rbio->real_stripes, PAGE_SIZE,
1271 pointers);
1272 } else {
1273 /* raid5 */
1274 copy_page(pointers[nr_data], pointers[0]);
1275 run_xor(pointers + 1, nr_data - 1, PAGE_SIZE);
1276 }
1277
1278
1279 for (stripe = 0; stripe < rbio->real_stripes; stripe++)
1280 kunmap(page_in_rbio(rbio, stripe, pagenr, 0));
1281 }
1282
1283 /*
1284 * time to start writing. Make bios for everything from the
1285 * higher layers (the bio_list in our rbio) and our p/q. Ignore
1286 * everything else.
1287 */
1288 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1289 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1290 struct page *page;
1291 if (stripe < rbio->nr_data) {
1292 page = page_in_rbio(rbio, stripe, pagenr, 1);
1293 if (!page)
1294 continue;
1295 } else {
1296 page = rbio_stripe_page(rbio, stripe, pagenr);
1297 }
1298
1299 ret = rbio_add_io_page(rbio, &bio_list,
1300 page, stripe, pagenr, rbio->stripe_len);
1301 if (ret)
1302 goto cleanup;
1303 }
1304 }
1305
1306 if (likely(!bbio->num_tgtdevs))
1307 goto write_data;
1308
1309 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1310 if (!bbio->tgtdev_map[stripe])
1311 continue;
1312
1313 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1314 struct page *page;
1315 if (stripe < rbio->nr_data) {
1316 page = page_in_rbio(rbio, stripe, pagenr, 1);
1317 if (!page)
1318 continue;
1319 } else {
1320 page = rbio_stripe_page(rbio, stripe, pagenr);
1321 }
1322
1323 ret = rbio_add_io_page(rbio, &bio_list, page,
1324 rbio->bbio->tgtdev_map[stripe],
1325 pagenr, rbio->stripe_len);
1326 if (ret)
1327 goto cleanup;
1328 }
1329 }
1330
1331write_data:
1332 atomic_set(&rbio->stripes_pending, bio_list_size(&bio_list));
1333 BUG_ON(atomic_read(&rbio->stripes_pending) == 0);
1334
1335 while (1) {
1336 bio = bio_list_pop(&bio_list);
1337 if (!bio)
1338 break;
1339
1340 bio->bi_private = rbio;
1341 bio->bi_end_io = raid_write_end_io;
1342 bio->bi_opf = REQ_OP_WRITE;
1343
1344 submit_bio(bio);
1345 }
1346 return;
1347
1348cleanup:
1349 rbio_orig_end_io(rbio, BLK_STS_IOERR);
1350
1351 while ((bio = bio_list_pop(&bio_list)))
1352 bio_put(bio);
1353}
1354
1355/*
1356 * helper to find the stripe number for a given bio. Used to figure out which
1357 * stripe has failed. This expects the bio to correspond to a physical disk,
1358 * so it looks up based on physical sector numbers.
1359 */
1360static int find_bio_stripe(struct btrfs_raid_bio *rbio,
1361 struct bio *bio)
1362{
1363 u64 physical = bio->bi_iter.bi_sector;
1364 u64 stripe_start;
1365 int i;
1366 struct btrfs_bio_stripe *stripe;
1367
1368 physical <<= 9;
1369
1370 for (i = 0; i < rbio->bbio->num_stripes; i++) {
1371 stripe = &rbio->bbio->stripes[i];
1372 stripe_start = stripe->physical;
1373 if (physical >= stripe_start &&
1374 physical < stripe_start + rbio->stripe_len &&
1375 stripe->dev->bdev &&
1376 bio->bi_disk == stripe->dev->bdev->bd_disk &&
1377 bio->bi_partno == stripe->dev->bdev->bd_partno) {
1378 return i;
1379 }
1380 }
1381 return -1;
1382}
1383
1384/*
1385 * helper to find the stripe number for a given
1386 * bio (before mapping). Used to figure out which stripe has
1387 * failed. This looks up based on logical block numbers.
1388 */
1389static int find_logical_bio_stripe(struct btrfs_raid_bio *rbio,
1390 struct bio *bio)
1391{
1392 u64 logical = bio->bi_iter.bi_sector;
1393 u64 stripe_start;
1394 int i;
1395
1396 logical <<= 9;
1397
1398 for (i = 0; i < rbio->nr_data; i++) {
1399 stripe_start = rbio->bbio->raid_map[i];
1400 if (logical >= stripe_start &&
1401 logical < stripe_start + rbio->stripe_len) {
1402 return i;
1403 }
1404 }
1405 return -1;
1406}
1407
1408/*
1409 * returns -EIO if we had too many failures
1410 */
1411static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed)
1412{
1413 unsigned long flags;
1414 int ret = 0;
1415
1416 spin_lock_irqsave(&rbio->bio_list_lock, flags);
1417
1418 /* we already know this stripe is bad, move on */
1419 if (rbio->faila == failed || rbio->failb == failed)
1420 goto out;
1421
1422 if (rbio->faila == -1) {
1423 /* first failure on this rbio */
1424 rbio->faila = failed;
1425 atomic_inc(&rbio->error);
1426 } else if (rbio->failb == -1) {
1427 /* second failure on this rbio */
1428 rbio->failb = failed;
1429 atomic_inc(&rbio->error);
1430 } else {
1431 ret = -EIO;
1432 }
1433out:
1434 spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
1435
1436 return ret;
1437}
1438
1439/*
1440 * helper to fail a stripe based on a physical disk
1441 * bio.
1442 */
1443static int fail_bio_stripe(struct btrfs_raid_bio *rbio,
1444 struct bio *bio)
1445{
1446 int failed = find_bio_stripe(rbio, bio);
1447
1448 if (failed < 0)
1449 return -EIO;
1450
1451 return fail_rbio_index(rbio, failed);
1452}
1453
1454/*
1455 * this sets each page in the bio uptodate. It should only be used on private
1456 * rbio pages, nothing that comes in from the higher layers
1457 */
1458static void set_bio_pages_uptodate(struct bio *bio)
1459{
1460 struct bio_vec *bvec;
1461 struct bvec_iter_all iter_all;
1462
1463 ASSERT(!bio_flagged(bio, BIO_CLONED));
1464
1465 bio_for_each_segment_all(bvec, bio, iter_all)
1466 SetPageUptodate(bvec->bv_page);
1467}
1468
1469/*
1470 * end io for the read phase of the rmw cycle. All the bios here are physical
1471 * stripe bios we've read from the disk so we can recalculate the parity of the
1472 * stripe.
1473 *
1474 * This will usually kick off finish_rmw once all the bios are read in, but it
1475 * may trigger parity reconstruction if we had any errors along the way
1476 */
1477static void raid_rmw_end_io(struct bio *bio)
1478{
1479 struct btrfs_raid_bio *rbio = bio->bi_private;
1480
1481 if (bio->bi_status)
1482 fail_bio_stripe(rbio, bio);
1483 else
1484 set_bio_pages_uptodate(bio);
1485
1486 bio_put(bio);
1487
1488 if (!atomic_dec_and_test(&rbio->stripes_pending))
1489 return;
1490
1491 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
1492 goto cleanup;
1493
1494 /*
1495 * this will normally call finish_rmw to start our write
1496 * but if there are any failed stripes we'll reconstruct
1497 * from parity first
1498 */
1499 validate_rbio_for_rmw(rbio);
1500 return;
1501
1502cleanup:
1503
1504 rbio_orig_end_io(rbio, BLK_STS_IOERR);
1505}
1506
1507/*
1508 * the stripe must be locked by the caller. It will
1509 * unlock after all the writes are done
1510 */
1511static int raid56_rmw_stripe(struct btrfs_raid_bio *rbio)
1512{
1513 int bios_to_read = 0;
1514 struct bio_list bio_list;
1515 int ret;
1516 int pagenr;
1517 int stripe;
1518 struct bio *bio;
1519
1520 bio_list_init(&bio_list);
1521
1522 ret = alloc_rbio_pages(rbio);
1523 if (ret)
1524 goto cleanup;
1525
1526 index_rbio_pages(rbio);
1527
1528 atomic_set(&rbio->error, 0);
1529 /*
1530 * build a list of bios to read all the missing parts of this
1531 * stripe
1532 */
1533 for (stripe = 0; stripe < rbio->nr_data; stripe++) {
1534 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1535 struct page *page;
1536 /*
1537 * we want to find all the pages missing from
1538 * the rbio and read them from the disk. If
1539 * page_in_rbio finds a page in the bio list
1540 * we don't need to read it off the stripe.
1541 */
1542 page = page_in_rbio(rbio, stripe, pagenr, 1);
1543 if (page)
1544 continue;
1545
1546 page = rbio_stripe_page(rbio, stripe, pagenr);
1547 /*
1548 * the bio cache may have handed us an uptodate
1549 * page. If so, be happy and use it
1550 */
1551 if (PageUptodate(page))
1552 continue;
1553
1554 ret = rbio_add_io_page(rbio, &bio_list, page,
1555 stripe, pagenr, rbio->stripe_len);
1556 if (ret)
1557 goto cleanup;
1558 }
1559 }
1560
1561 bios_to_read = bio_list_size(&bio_list);
1562 if (!bios_to_read) {
1563 /*
1564 * this can happen if others have merged with
1565 * us, it means there is nothing left to read.
1566 * But if there are missing devices it may not be
1567 * safe to do the full stripe write yet.
1568 */
1569 goto finish;
1570 }
1571
1572 /*
1573 * the bbio may be freed once we submit the last bio. Make sure
1574 * not to touch it after that
1575 */
1576 atomic_set(&rbio->stripes_pending, bios_to_read);
1577 while (1) {
1578 bio = bio_list_pop(&bio_list);
1579 if (!bio)
1580 break;
1581
1582 bio->bi_private = rbio;
1583 bio->bi_end_io = raid_rmw_end_io;
1584 bio->bi_opf = REQ_OP_READ;
1585
1586 btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
1587
1588 submit_bio(bio);
1589 }
1590 /* the actual write will happen once the reads are done */
1591 return 0;
1592
1593cleanup:
1594 rbio_orig_end_io(rbio, BLK_STS_IOERR);
1595
1596 while ((bio = bio_list_pop(&bio_list)))
1597 bio_put(bio);
1598
1599 return -EIO;
1600
1601finish:
1602 validate_rbio_for_rmw(rbio);
1603 return 0;
1604}
1605
1606/*
1607 * if the upper layers pass in a full stripe, we thank them by only allocating
1608 * enough pages to hold the parity, and sending it all down quickly.
1609 */
1610static int full_stripe_write(struct btrfs_raid_bio *rbio)
1611{
1612 int ret;
1613
1614 ret = alloc_rbio_parity_pages(rbio);
1615 if (ret) {
1616 __free_raid_bio(rbio);
1617 return ret;
1618 }
1619
1620 ret = lock_stripe_add(rbio);
1621 if (ret == 0)
1622 finish_rmw(rbio);
1623 return 0;
1624}
1625
1626/*
1627 * partial stripe writes get handed over to async helpers.
1628 * We're really hoping to merge a few more writes into this
1629 * rbio before calculating new parity
1630 */
1631static int partial_stripe_write(struct btrfs_raid_bio *rbio)
1632{
1633 int ret;
1634
1635 ret = lock_stripe_add(rbio);
1636 if (ret == 0)
1637 start_async_work(rbio, rmw_work);
1638 return 0;
1639}
1640
1641/*
1642 * sometimes while we were reading from the drive to
1643 * recalculate parity, enough new bios come into create
1644 * a full stripe. So we do a check here to see if we can
1645 * go directly to finish_rmw
1646 */
1647static int __raid56_parity_write(struct btrfs_raid_bio *rbio)
1648{
1649 /* head off into rmw land if we don't have a full stripe */
1650 if (!rbio_is_full(rbio))
1651 return partial_stripe_write(rbio);
1652 return full_stripe_write(rbio);
1653}
1654
1655/*
1656 * We use plugging call backs to collect full stripes.
1657 * Any time we get a partial stripe write while plugged
1658 * we collect it into a list. When the unplug comes down,
1659 * we sort the list by logical block number and merge
1660 * everything we can into the same rbios
1661 */
1662struct btrfs_plug_cb {
1663 struct blk_plug_cb cb;
1664 struct btrfs_fs_info *info;
1665 struct list_head rbio_list;
1666 struct btrfs_work work;
1667};
1668
1669/*
1670 * rbios on the plug list are sorted for easier merging.
1671 */
1672static int plug_cmp(void *priv, struct list_head *a, struct list_head *b)
1673{
1674 struct btrfs_raid_bio *ra = container_of(a, struct btrfs_raid_bio,
1675 plug_list);
1676 struct btrfs_raid_bio *rb = container_of(b, struct btrfs_raid_bio,
1677 plug_list);
1678 u64 a_sector = ra->bio_list.head->bi_iter.bi_sector;
1679 u64 b_sector = rb->bio_list.head->bi_iter.bi_sector;
1680
1681 if (a_sector < b_sector)
1682 return -1;
1683 if (a_sector > b_sector)
1684 return 1;
1685 return 0;
1686}
1687
1688static void run_plug(struct btrfs_plug_cb *plug)
1689{
1690 struct btrfs_raid_bio *cur;
1691 struct btrfs_raid_bio *last = NULL;
1692
1693 /*
1694 * sort our plug list then try to merge
1695 * everything we can in hopes of creating full
1696 * stripes.
1697 */
1698 list_sort(NULL, &plug->rbio_list, plug_cmp);
1699 while (!list_empty(&plug->rbio_list)) {
1700 cur = list_entry(plug->rbio_list.next,
1701 struct btrfs_raid_bio, plug_list);
1702 list_del_init(&cur->plug_list);
1703
1704 if (rbio_is_full(cur)) {
1705 int ret;
1706
1707 /* we have a full stripe, send it down */
1708 ret = full_stripe_write(cur);
1709 BUG_ON(ret);
1710 continue;
1711 }
1712 if (last) {
1713 if (rbio_can_merge(last, cur)) {
1714 merge_rbio(last, cur);
1715 __free_raid_bio(cur);
1716 continue;
1717
1718 }
1719 __raid56_parity_write(last);
1720 }
1721 last = cur;
1722 }
1723 if (last) {
1724 __raid56_parity_write(last);
1725 }
1726 kfree(plug);
1727}
1728
1729/*
1730 * if the unplug comes from schedule, we have to push the
1731 * work off to a helper thread
1732 */
1733static void unplug_work(struct btrfs_work *work)
1734{
1735 struct btrfs_plug_cb *plug;
1736 plug = container_of(work, struct btrfs_plug_cb, work);
1737 run_plug(plug);
1738}
1739
1740static void btrfs_raid_unplug(struct blk_plug_cb *cb, bool from_schedule)
1741{
1742 struct btrfs_plug_cb *plug;
1743 plug = container_of(cb, struct btrfs_plug_cb, cb);
1744
1745 if (from_schedule) {
1746 btrfs_init_work(&plug->work, btrfs_rmw_helper,
1747 unplug_work, NULL, NULL);
1748 btrfs_queue_work(plug->info->rmw_workers,
1749 &plug->work);
1750 return;
1751 }
1752 run_plug(plug);
1753}
1754
1755/*
1756 * our main entry point for writes from the rest of the FS.
1757 */
1758int raid56_parity_write(struct btrfs_fs_info *fs_info, struct bio *bio,
1759 struct btrfs_bio *bbio, u64 stripe_len)
1760{
1761 struct btrfs_raid_bio *rbio;
1762 struct btrfs_plug_cb *plug = NULL;
1763 struct blk_plug_cb *cb;
1764 int ret;
1765
1766 rbio = alloc_rbio(fs_info, bbio, stripe_len);
1767 if (IS_ERR(rbio)) {
1768 btrfs_put_bbio(bbio);
1769 return PTR_ERR(rbio);
1770 }
1771 bio_list_add(&rbio->bio_list, bio);
1772 rbio->bio_list_bytes = bio->bi_iter.bi_size;
1773 rbio->operation = BTRFS_RBIO_WRITE;
1774
1775 btrfs_bio_counter_inc_noblocked(fs_info);
1776 rbio->generic_bio_cnt = 1;
1777
1778 /*
1779 * don't plug on full rbios, just get them out the door
1780 * as quickly as we can
1781 */
1782 if (rbio_is_full(rbio)) {
1783 ret = full_stripe_write(rbio);
1784 if (ret)
1785 btrfs_bio_counter_dec(fs_info);
1786 return ret;
1787 }
1788
1789 cb = blk_check_plugged(btrfs_raid_unplug, fs_info, sizeof(*plug));
1790 if (cb) {
1791 plug = container_of(cb, struct btrfs_plug_cb, cb);
1792 if (!plug->info) {
1793 plug->info = fs_info;
1794 INIT_LIST_HEAD(&plug->rbio_list);
1795 }
1796 list_add_tail(&rbio->plug_list, &plug->rbio_list);
1797 ret = 0;
1798 } else {
1799 ret = __raid56_parity_write(rbio);
1800 if (ret)
1801 btrfs_bio_counter_dec(fs_info);
1802 }
1803 return ret;
1804}
1805
1806/*
1807 * all parity reconstruction happens here. We've read in everything
1808 * we can find from the drives and this does the heavy lifting of
1809 * sorting the good from the bad.
1810 */
1811static void __raid_recover_end_io(struct btrfs_raid_bio *rbio)
1812{
1813 int pagenr, stripe;
1814 void **pointers;
1815 int faila = -1, failb = -1;
1816 struct page *page;
1817 blk_status_t err;
1818 int i;
1819
1820 pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
1821 if (!pointers) {
1822 err = BLK_STS_RESOURCE;
1823 goto cleanup_io;
1824 }
1825
1826 faila = rbio->faila;
1827 failb = rbio->failb;
1828
1829 if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1830 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) {
1831 spin_lock_irq(&rbio->bio_list_lock);
1832 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1833 spin_unlock_irq(&rbio->bio_list_lock);
1834 }
1835
1836 index_rbio_pages(rbio);
1837
1838 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1839 /*
1840 * Now we just use bitmap to mark the horizontal stripes in
1841 * which we have data when doing parity scrub.
1842 */
1843 if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB &&
1844 !test_bit(pagenr, rbio->dbitmap))
1845 continue;
1846
1847 /* setup our array of pointers with pages
1848 * from each stripe
1849 */
1850 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1851 /*
1852 * if we're rebuilding a read, we have to use
1853 * pages from the bio list
1854 */
1855 if ((rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1856 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) &&
1857 (stripe == faila || stripe == failb)) {
1858 page = page_in_rbio(rbio, stripe, pagenr, 0);
1859 } else {
1860 page = rbio_stripe_page(rbio, stripe, pagenr);
1861 }
1862 pointers[stripe] = kmap(page);
1863 }
1864
1865 /* all raid6 handling here */
1866 if (rbio->bbio->map_type & BTRFS_BLOCK_GROUP_RAID6) {
1867 /*
1868 * single failure, rebuild from parity raid5
1869 * style
1870 */
1871 if (failb < 0) {
1872 if (faila == rbio->nr_data) {
1873 /*
1874 * Just the P stripe has failed, without
1875 * a bad data or Q stripe.
1876 * TODO, we should redo the xor here.
1877 */
1878 err = BLK_STS_IOERR;
1879 goto cleanup;
1880 }
1881 /*
1882 * a single failure in raid6 is rebuilt
1883 * in the pstripe code below
1884 */
1885 goto pstripe;
1886 }
1887
1888 /* make sure our ps and qs are in order */
1889 if (faila > failb) {
1890 int tmp = failb;
1891 failb = faila;
1892 faila = tmp;
1893 }
1894
1895 /* if the q stripe is failed, do a pstripe reconstruction
1896 * from the xors.
1897 * If both the q stripe and the P stripe are failed, we're
1898 * here due to a crc mismatch and we can't give them the
1899 * data they want
1900 */
1901 if (rbio->bbio->raid_map[failb] == RAID6_Q_STRIPE) {
1902 if (rbio->bbio->raid_map[faila] ==
1903 RAID5_P_STRIPE) {
1904 err = BLK_STS_IOERR;
1905 goto cleanup;
1906 }
1907 /*
1908 * otherwise we have one bad data stripe and
1909 * a good P stripe. raid5!
1910 */
1911 goto pstripe;
1912 }
1913
1914 if (rbio->bbio->raid_map[failb] == RAID5_P_STRIPE) {
1915 raid6_datap_recov(rbio->real_stripes,
1916 PAGE_SIZE, faila, pointers);
1917 } else {
1918 raid6_2data_recov(rbio->real_stripes,
1919 PAGE_SIZE, faila, failb,
1920 pointers);
1921 }
1922 } else {
1923 void *p;
1924
1925 /* rebuild from P stripe here (raid5 or raid6) */
1926 BUG_ON(failb != -1);
1927pstripe:
1928 /* Copy parity block into failed block to start with */
1929 copy_page(pointers[faila], pointers[rbio->nr_data]);
1930
1931 /* rearrange the pointer array */
1932 p = pointers[faila];
1933 for (stripe = faila; stripe < rbio->nr_data - 1; stripe++)
1934 pointers[stripe] = pointers[stripe + 1];
1935 pointers[rbio->nr_data - 1] = p;
1936
1937 /* xor in the rest */
1938 run_xor(pointers, rbio->nr_data - 1, PAGE_SIZE);
1939 }
1940 /* if we're doing this rebuild as part of an rmw, go through
1941 * and set all of our private rbio pages in the
1942 * failed stripes as uptodate. This way finish_rmw will
1943 * know they can be trusted. If this was a read reconstruction,
1944 * other endio functions will fiddle the uptodate bits
1945 */
1946 if (rbio->operation == BTRFS_RBIO_WRITE) {
1947 for (i = 0; i < rbio->stripe_npages; i++) {
1948 if (faila != -1) {
1949 page = rbio_stripe_page(rbio, faila, i);
1950 SetPageUptodate(page);
1951 }
1952 if (failb != -1) {
1953 page = rbio_stripe_page(rbio, failb, i);
1954 SetPageUptodate(page);
1955 }
1956 }
1957 }
1958 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1959 /*
1960 * if we're rebuilding a read, we have to use
1961 * pages from the bio list
1962 */
1963 if ((rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1964 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) &&
1965 (stripe == faila || stripe == failb)) {
1966 page = page_in_rbio(rbio, stripe, pagenr, 0);
1967 } else {
1968 page = rbio_stripe_page(rbio, stripe, pagenr);
1969 }
1970 kunmap(page);
1971 }
1972 }
1973
1974 err = BLK_STS_OK;
1975cleanup:
1976 kfree(pointers);
1977
1978cleanup_io:
1979 /*
1980 * Similar to READ_REBUILD, REBUILD_MISSING at this point also has a
1981 * valid rbio which is consistent with ondisk content, thus such a
1982 * valid rbio can be cached to avoid further disk reads.
1983 */
1984 if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1985 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) {
1986 /*
1987 * - In case of two failures, where rbio->failb != -1:
1988 *
1989 * Do not cache this rbio since the above read reconstruction
1990 * (raid6_datap_recov() or raid6_2data_recov()) may have
1991 * changed some content of stripes which are not identical to
1992 * on-disk content any more, otherwise, a later write/recover
1993 * may steal stripe_pages from this rbio and end up with
1994 * corruptions or rebuild failures.
1995 *
1996 * - In case of single failure, where rbio->failb == -1:
1997 *
1998 * Cache this rbio iff the above read reconstruction is
1999 * executed without problems.
2000 */
2001 if (err == BLK_STS_OK && rbio->failb < 0)
2002 cache_rbio_pages(rbio);
2003 else
2004 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
2005
2006 rbio_orig_end_io(rbio, err);
2007 } else if (err == BLK_STS_OK) {
2008 rbio->faila = -1;
2009 rbio->failb = -1;
2010
2011 if (rbio->operation == BTRFS_RBIO_WRITE)
2012 finish_rmw(rbio);
2013 else if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB)
2014 finish_parity_scrub(rbio, 0);
2015 else
2016 BUG();
2017 } else {
2018 rbio_orig_end_io(rbio, err);
2019 }
2020}
2021
2022/*
2023 * This is called only for stripes we've read from disk to
2024 * reconstruct the parity.
2025 */
2026static void raid_recover_end_io(struct bio *bio)
2027{
2028 struct btrfs_raid_bio *rbio = bio->bi_private;
2029
2030 /*
2031 * we only read stripe pages off the disk, set them
2032 * up to date if there were no errors
2033 */
2034 if (bio->bi_status)
2035 fail_bio_stripe(rbio, bio);
2036 else
2037 set_bio_pages_uptodate(bio);
2038 bio_put(bio);
2039
2040 if (!atomic_dec_and_test(&rbio->stripes_pending))
2041 return;
2042
2043 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
2044 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2045 else
2046 __raid_recover_end_io(rbio);
2047}
2048
2049/*
2050 * reads everything we need off the disk to reconstruct
2051 * the parity. endio handlers trigger final reconstruction
2052 * when the IO is done.
2053 *
2054 * This is used both for reads from the higher layers and for
2055 * parity construction required to finish a rmw cycle.
2056 */
2057static int __raid56_parity_recover(struct btrfs_raid_bio *rbio)
2058{
2059 int bios_to_read = 0;
2060 struct bio_list bio_list;
2061 int ret;
2062 int pagenr;
2063 int stripe;
2064 struct bio *bio;
2065
2066 bio_list_init(&bio_list);
2067
2068 ret = alloc_rbio_pages(rbio);
2069 if (ret)
2070 goto cleanup;
2071
2072 atomic_set(&rbio->error, 0);
2073
2074 /*
2075 * read everything that hasn't failed. Thanks to the
2076 * stripe cache, it is possible that some or all of these
2077 * pages are going to be uptodate.
2078 */
2079 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
2080 if (rbio->faila == stripe || rbio->failb == stripe) {
2081 atomic_inc(&rbio->error);
2082 continue;
2083 }
2084
2085 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
2086 struct page *p;
2087
2088 /*
2089 * the rmw code may have already read this
2090 * page in
2091 */
2092 p = rbio_stripe_page(rbio, stripe, pagenr);
2093 if (PageUptodate(p))
2094 continue;
2095
2096 ret = rbio_add_io_page(rbio, &bio_list,
2097 rbio_stripe_page(rbio, stripe, pagenr),
2098 stripe, pagenr, rbio->stripe_len);
2099 if (ret < 0)
2100 goto cleanup;
2101 }
2102 }
2103
2104 bios_to_read = bio_list_size(&bio_list);
2105 if (!bios_to_read) {
2106 /*
2107 * we might have no bios to read just because the pages
2108 * were up to date, or we might have no bios to read because
2109 * the devices were gone.
2110 */
2111 if (atomic_read(&rbio->error) <= rbio->bbio->max_errors) {
2112 __raid_recover_end_io(rbio);
2113 goto out;
2114 } else {
2115 goto cleanup;
2116 }
2117 }
2118
2119 /*
2120 * the bbio may be freed once we submit the last bio. Make sure
2121 * not to touch it after that
2122 */
2123 atomic_set(&rbio->stripes_pending, bios_to_read);
2124 while (1) {
2125 bio = bio_list_pop(&bio_list);
2126 if (!bio)
2127 break;
2128
2129 bio->bi_private = rbio;
2130 bio->bi_end_io = raid_recover_end_io;
2131 bio->bi_opf = REQ_OP_READ;
2132
2133 btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
2134
2135 submit_bio(bio);
2136 }
2137out:
2138 return 0;
2139
2140cleanup:
2141 if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
2142 rbio->operation == BTRFS_RBIO_REBUILD_MISSING)
2143 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2144
2145 while ((bio = bio_list_pop(&bio_list)))
2146 bio_put(bio);
2147
2148 return -EIO;
2149}
2150
2151/*
2152 * the main entry point for reads from the higher layers. This
2153 * is really only called when the normal read path had a failure,
2154 * so we assume the bio they send down corresponds to a failed part
2155 * of the drive.
2156 */
2157int raid56_parity_recover(struct btrfs_fs_info *fs_info, struct bio *bio,
2158 struct btrfs_bio *bbio, u64 stripe_len,
2159 int mirror_num, int generic_io)
2160{
2161 struct btrfs_raid_bio *rbio;
2162 int ret;
2163
2164 if (generic_io) {
2165 ASSERT(bbio->mirror_num == mirror_num);
2166 btrfs_io_bio(bio)->mirror_num = mirror_num;
2167 }
2168
2169 rbio = alloc_rbio(fs_info, bbio, stripe_len);
2170 if (IS_ERR(rbio)) {
2171 if (generic_io)
2172 btrfs_put_bbio(bbio);
2173 return PTR_ERR(rbio);
2174 }
2175
2176 rbio->operation = BTRFS_RBIO_READ_REBUILD;
2177 bio_list_add(&rbio->bio_list, bio);
2178 rbio->bio_list_bytes = bio->bi_iter.bi_size;
2179
2180 rbio->faila = find_logical_bio_stripe(rbio, bio);
2181 if (rbio->faila == -1) {
2182 btrfs_warn(fs_info,
2183 "%s could not find the bad stripe in raid56 so that we cannot recover any more (bio has logical %llu len %llu, bbio has map_type %llu)",
2184 __func__, (u64)bio->bi_iter.bi_sector << 9,
2185 (u64)bio->bi_iter.bi_size, bbio->map_type);
2186 if (generic_io)
2187 btrfs_put_bbio(bbio);
2188 kfree(rbio);
2189 return -EIO;
2190 }
2191
2192 if (generic_io) {
2193 btrfs_bio_counter_inc_noblocked(fs_info);
2194 rbio->generic_bio_cnt = 1;
2195 } else {
2196 btrfs_get_bbio(bbio);
2197 }
2198
2199 /*
2200 * Loop retry:
2201 * for 'mirror == 2', reconstruct from all other stripes.
2202 * for 'mirror_num > 2', select a stripe to fail on every retry.
2203 */
2204 if (mirror_num > 2) {
2205 /*
2206 * 'mirror == 3' is to fail the p stripe and
2207 * reconstruct from the q stripe. 'mirror > 3' is to
2208 * fail a data stripe and reconstruct from p+q stripe.
2209 */
2210 rbio->failb = rbio->real_stripes - (mirror_num - 1);
2211 ASSERT(rbio->failb > 0);
2212 if (rbio->failb <= rbio->faila)
2213 rbio->failb--;
2214 }
2215
2216 ret = lock_stripe_add(rbio);
2217
2218 /*
2219 * __raid56_parity_recover will end the bio with
2220 * any errors it hits. We don't want to return
2221 * its error value up the stack because our caller
2222 * will end up calling bio_endio with any nonzero
2223 * return
2224 */
2225 if (ret == 0)
2226 __raid56_parity_recover(rbio);
2227 /*
2228 * our rbio has been added to the list of
2229 * rbios that will be handled after the
2230 * currently lock owner is done
2231 */
2232 return 0;
2233
2234}
2235
2236static void rmw_work(struct btrfs_work *work)
2237{
2238 struct btrfs_raid_bio *rbio;
2239
2240 rbio = container_of(work, struct btrfs_raid_bio, work);
2241 raid56_rmw_stripe(rbio);
2242}
2243
2244static void read_rebuild_work(struct btrfs_work *work)
2245{
2246 struct btrfs_raid_bio *rbio;
2247
2248 rbio = container_of(work, struct btrfs_raid_bio, work);
2249 __raid56_parity_recover(rbio);
2250}
2251
2252/*
2253 * The following code is used to scrub/replace the parity stripe
2254 *
2255 * Caller must have already increased bio_counter for getting @bbio.
2256 *
2257 * Note: We need make sure all the pages that add into the scrub/replace
2258 * raid bio are correct and not be changed during the scrub/replace. That
2259 * is those pages just hold metadata or file data with checksum.
2260 */
2261
2262struct btrfs_raid_bio *
2263raid56_parity_alloc_scrub_rbio(struct btrfs_fs_info *fs_info, struct bio *bio,
2264 struct btrfs_bio *bbio, u64 stripe_len,
2265 struct btrfs_device *scrub_dev,
2266 unsigned long *dbitmap, int stripe_nsectors)
2267{
2268 struct btrfs_raid_bio *rbio;
2269 int i;
2270
2271 rbio = alloc_rbio(fs_info, bbio, stripe_len);
2272 if (IS_ERR(rbio))
2273 return NULL;
2274 bio_list_add(&rbio->bio_list, bio);
2275 /*
2276 * This is a special bio which is used to hold the completion handler
2277 * and make the scrub rbio is similar to the other types
2278 */
2279 ASSERT(!bio->bi_iter.bi_size);
2280 rbio->operation = BTRFS_RBIO_PARITY_SCRUB;
2281
2282 /*
2283 * After mapping bbio with BTRFS_MAP_WRITE, parities have been sorted
2284 * to the end position, so this search can start from the first parity
2285 * stripe.
2286 */
2287 for (i = rbio->nr_data; i < rbio->real_stripes; i++) {
2288 if (bbio->stripes[i].dev == scrub_dev) {
2289 rbio->scrubp = i;
2290 break;
2291 }
2292 }
2293 ASSERT(i < rbio->real_stripes);
2294
2295 /* Now we just support the sectorsize equals to page size */
2296 ASSERT(fs_info->sectorsize == PAGE_SIZE);
2297 ASSERT(rbio->stripe_npages == stripe_nsectors);
2298 bitmap_copy(rbio->dbitmap, dbitmap, stripe_nsectors);
2299
2300 /*
2301 * We have already increased bio_counter when getting bbio, record it
2302 * so we can free it at rbio_orig_end_io().
2303 */
2304 rbio->generic_bio_cnt = 1;
2305
2306 return rbio;
2307}
2308
2309/* Used for both parity scrub and missing. */
2310void raid56_add_scrub_pages(struct btrfs_raid_bio *rbio, struct page *page,
2311 u64 logical)
2312{
2313 int stripe_offset;
2314 int index;
2315
2316 ASSERT(logical >= rbio->bbio->raid_map[0]);
2317 ASSERT(logical + PAGE_SIZE <= rbio->bbio->raid_map[0] +
2318 rbio->stripe_len * rbio->nr_data);
2319 stripe_offset = (int)(logical - rbio->bbio->raid_map[0]);
2320 index = stripe_offset >> PAGE_SHIFT;
2321 rbio->bio_pages[index] = page;
2322}
2323
2324/*
2325 * We just scrub the parity that we have correct data on the same horizontal,
2326 * so we needn't allocate all pages for all the stripes.
2327 */
2328static int alloc_rbio_essential_pages(struct btrfs_raid_bio *rbio)
2329{
2330 int i;
2331 int bit;
2332 int index;
2333 struct page *page;
2334
2335 for_each_set_bit(bit, rbio->dbitmap, rbio->stripe_npages) {
2336 for (i = 0; i < rbio->real_stripes; i++) {
2337 index = i * rbio->stripe_npages + bit;
2338 if (rbio->stripe_pages[index])
2339 continue;
2340
2341 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2342 if (!page)
2343 return -ENOMEM;
2344 rbio->stripe_pages[index] = page;
2345 }
2346 }
2347 return 0;
2348}
2349
2350static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
2351 int need_check)
2352{
2353 struct btrfs_bio *bbio = rbio->bbio;
2354 void **pointers = rbio->finish_pointers;
2355 unsigned long *pbitmap = rbio->finish_pbitmap;
2356 int nr_data = rbio->nr_data;
2357 int stripe;
2358 int pagenr;
2359 int p_stripe = -1;
2360 int q_stripe = -1;
2361 struct page *p_page = NULL;
2362 struct page *q_page = NULL;
2363 struct bio_list bio_list;
2364 struct bio *bio;
2365 int is_replace = 0;
2366 int ret;
2367
2368 bio_list_init(&bio_list);
2369
2370 if (rbio->real_stripes - rbio->nr_data == 1) {
2371 p_stripe = rbio->real_stripes - 1;
2372 } else if (rbio->real_stripes - rbio->nr_data == 2) {
2373 p_stripe = rbio->real_stripes - 2;
2374 q_stripe = rbio->real_stripes - 1;
2375 } else {
2376 BUG();
2377 }
2378
2379 if (bbio->num_tgtdevs && bbio->tgtdev_map[rbio->scrubp]) {
2380 is_replace = 1;
2381 bitmap_copy(pbitmap, rbio->dbitmap, rbio->stripe_npages);
2382 }
2383
2384 /*
2385 * Because the higher layers(scrubber) are unlikely to
2386 * use this area of the disk again soon, so don't cache
2387 * it.
2388 */
2389 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
2390
2391 if (!need_check)
2392 goto writeback;
2393
2394 p_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2395 if (!p_page)
2396 goto cleanup;
2397 SetPageUptodate(p_page);
2398
2399 if (q_stripe != -1) {
2400 q_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2401 if (!q_page) {
2402 __free_page(p_page);
2403 goto cleanup;
2404 }
2405 SetPageUptodate(q_page);
2406 }
2407
2408 atomic_set(&rbio->error, 0);
2409
2410 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2411 struct page *p;
2412 void *parity;
2413 /* first collect one page from each data stripe */
2414 for (stripe = 0; stripe < nr_data; stripe++) {
2415 p = page_in_rbio(rbio, stripe, pagenr, 0);
2416 pointers[stripe] = kmap(p);
2417 }
2418
2419 /* then add the parity stripe */
2420 pointers[stripe++] = kmap(p_page);
2421
2422 if (q_stripe != -1) {
2423
2424 /*
2425 * raid6, add the qstripe and call the
2426 * library function to fill in our p/q
2427 */
2428 pointers[stripe++] = kmap(q_page);
2429
2430 raid6_call.gen_syndrome(rbio->real_stripes, PAGE_SIZE,
2431 pointers);
2432 } else {
2433 /* raid5 */
2434 copy_page(pointers[nr_data], pointers[0]);
2435 run_xor(pointers + 1, nr_data - 1, PAGE_SIZE);
2436 }
2437
2438 /* Check scrubbing parity and repair it */
2439 p = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2440 parity = kmap(p);
2441 if (memcmp(parity, pointers[rbio->scrubp], PAGE_SIZE))
2442 copy_page(parity, pointers[rbio->scrubp]);
2443 else
2444 /* Parity is right, needn't writeback */
2445 bitmap_clear(rbio->dbitmap, pagenr, 1);
2446 kunmap(p);
2447
2448 for (stripe = 0; stripe < nr_data; stripe++)
2449 kunmap(page_in_rbio(rbio, stripe, pagenr, 0));
2450 kunmap(p_page);
2451 }
2452
2453 __free_page(p_page);
2454 if (q_page)
2455 __free_page(q_page);
2456
2457writeback:
2458 /*
2459 * time to start writing. Make bios for everything from the
2460 * higher layers (the bio_list in our rbio) and our p/q. Ignore
2461 * everything else.
2462 */
2463 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2464 struct page *page;
2465
2466 page = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2467 ret = rbio_add_io_page(rbio, &bio_list,
2468 page, rbio->scrubp, pagenr, rbio->stripe_len);
2469 if (ret)
2470 goto cleanup;
2471 }
2472
2473 if (!is_replace)
2474 goto submit_write;
2475
2476 for_each_set_bit(pagenr, pbitmap, rbio->stripe_npages) {
2477 struct page *page;
2478
2479 page = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2480 ret = rbio_add_io_page(rbio, &bio_list, page,
2481 bbio->tgtdev_map[rbio->scrubp],
2482 pagenr, rbio->stripe_len);
2483 if (ret)
2484 goto cleanup;
2485 }
2486
2487submit_write:
2488 nr_data = bio_list_size(&bio_list);
2489 if (!nr_data) {
2490 /* Every parity is right */
2491 rbio_orig_end_io(rbio, BLK_STS_OK);
2492 return;
2493 }
2494
2495 atomic_set(&rbio->stripes_pending, nr_data);
2496
2497 while (1) {
2498 bio = bio_list_pop(&bio_list);
2499 if (!bio)
2500 break;
2501
2502 bio->bi_private = rbio;
2503 bio->bi_end_io = raid_write_end_io;
2504 bio->bi_opf = REQ_OP_WRITE;
2505
2506 submit_bio(bio);
2507 }
2508 return;
2509
2510cleanup:
2511 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2512
2513 while ((bio = bio_list_pop(&bio_list)))
2514 bio_put(bio);
2515}
2516
2517static inline int is_data_stripe(struct btrfs_raid_bio *rbio, int stripe)
2518{
2519 if (stripe >= 0 && stripe < rbio->nr_data)
2520 return 1;
2521 return 0;
2522}
2523
2524/*
2525 * While we're doing the parity check and repair, we could have errors
2526 * in reading pages off the disk. This checks for errors and if we're
2527 * not able to read the page it'll trigger parity reconstruction. The
2528 * parity scrub will be finished after we've reconstructed the failed
2529 * stripes
2530 */
2531static void validate_rbio_for_parity_scrub(struct btrfs_raid_bio *rbio)
2532{
2533 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
2534 goto cleanup;
2535
2536 if (rbio->faila >= 0 || rbio->failb >= 0) {
2537 int dfail = 0, failp = -1;
2538
2539 if (is_data_stripe(rbio, rbio->faila))
2540 dfail++;
2541 else if (is_parity_stripe(rbio->faila))
2542 failp = rbio->faila;
2543
2544 if (is_data_stripe(rbio, rbio->failb))
2545 dfail++;
2546 else if (is_parity_stripe(rbio->failb))
2547 failp = rbio->failb;
2548
2549 /*
2550 * Because we can not use a scrubbing parity to repair
2551 * the data, so the capability of the repair is declined.
2552 * (In the case of RAID5, we can not repair anything)
2553 */
2554 if (dfail > rbio->bbio->max_errors - 1)
2555 goto cleanup;
2556
2557 /*
2558 * If all data is good, only parity is correctly, just
2559 * repair the parity.
2560 */
2561 if (dfail == 0) {
2562 finish_parity_scrub(rbio, 0);
2563 return;
2564 }
2565
2566 /*
2567 * Here means we got one corrupted data stripe and one
2568 * corrupted parity on RAID6, if the corrupted parity
2569 * is scrubbing parity, luckily, use the other one to repair
2570 * the data, or we can not repair the data stripe.
2571 */
2572 if (failp != rbio->scrubp)
2573 goto cleanup;
2574
2575 __raid_recover_end_io(rbio);
2576 } else {
2577 finish_parity_scrub(rbio, 1);
2578 }
2579 return;
2580
2581cleanup:
2582 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2583}
2584
2585/*
2586 * end io for the read phase of the rmw cycle. All the bios here are physical
2587 * stripe bios we've read from the disk so we can recalculate the parity of the
2588 * stripe.
2589 *
2590 * This will usually kick off finish_rmw once all the bios are read in, but it
2591 * may trigger parity reconstruction if we had any errors along the way
2592 */
2593static void raid56_parity_scrub_end_io(struct bio *bio)
2594{
2595 struct btrfs_raid_bio *rbio = bio->bi_private;
2596
2597 if (bio->bi_status)
2598 fail_bio_stripe(rbio, bio);
2599 else
2600 set_bio_pages_uptodate(bio);
2601
2602 bio_put(bio);
2603
2604 if (!atomic_dec_and_test(&rbio->stripes_pending))
2605 return;
2606
2607 /*
2608 * this will normally call finish_rmw to start our write
2609 * but if there are any failed stripes we'll reconstruct
2610 * from parity first
2611 */
2612 validate_rbio_for_parity_scrub(rbio);
2613}
2614
2615static void raid56_parity_scrub_stripe(struct btrfs_raid_bio *rbio)
2616{
2617 int bios_to_read = 0;
2618 struct bio_list bio_list;
2619 int ret;
2620 int pagenr;
2621 int stripe;
2622 struct bio *bio;
2623
2624 bio_list_init(&bio_list);
2625
2626 ret = alloc_rbio_essential_pages(rbio);
2627 if (ret)
2628 goto cleanup;
2629
2630 atomic_set(&rbio->error, 0);
2631 /*
2632 * build a list of bios to read all the missing parts of this
2633 * stripe
2634 */
2635 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
2636 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2637 struct page *page;
2638 /*
2639 * we want to find all the pages missing from
2640 * the rbio and read them from the disk. If
2641 * page_in_rbio finds a page in the bio list
2642 * we don't need to read it off the stripe.
2643 */
2644 page = page_in_rbio(rbio, stripe, pagenr, 1);
2645 if (page)
2646 continue;
2647
2648 page = rbio_stripe_page(rbio, stripe, pagenr);
2649 /*
2650 * the bio cache may have handed us an uptodate
2651 * page. If so, be happy and use it
2652 */
2653 if (PageUptodate(page))
2654 continue;
2655
2656 ret = rbio_add_io_page(rbio, &bio_list, page,
2657 stripe, pagenr, rbio->stripe_len);
2658 if (ret)
2659 goto cleanup;
2660 }
2661 }
2662
2663 bios_to_read = bio_list_size(&bio_list);
2664 if (!bios_to_read) {
2665 /*
2666 * this can happen if others have merged with
2667 * us, it means there is nothing left to read.
2668 * But if there are missing devices it may not be
2669 * safe to do the full stripe write yet.
2670 */
2671 goto finish;
2672 }
2673
2674 /*
2675 * the bbio may be freed once we submit the last bio. Make sure
2676 * not to touch it after that
2677 */
2678 atomic_set(&rbio->stripes_pending, bios_to_read);
2679 while (1) {
2680 bio = bio_list_pop(&bio_list);
2681 if (!bio)
2682 break;
2683
2684 bio->bi_private = rbio;
2685 bio->bi_end_io = raid56_parity_scrub_end_io;
2686 bio->bi_opf = REQ_OP_READ;
2687
2688 btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
2689
2690 submit_bio(bio);
2691 }
2692 /* the actual write will happen once the reads are done */
2693 return;
2694
2695cleanup:
2696 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2697
2698 while ((bio = bio_list_pop(&bio_list)))
2699 bio_put(bio);
2700
2701 return;
2702
2703finish:
2704 validate_rbio_for_parity_scrub(rbio);
2705}
2706
2707static void scrub_parity_work(struct btrfs_work *work)
2708{
2709 struct btrfs_raid_bio *rbio;
2710
2711 rbio = container_of(work, struct btrfs_raid_bio, work);
2712 raid56_parity_scrub_stripe(rbio);
2713}
2714
2715void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio)
2716{
2717 if (!lock_stripe_add(rbio))
2718 start_async_work(rbio, scrub_parity_work);
2719}
2720
2721/* The following code is used for dev replace of a missing RAID 5/6 device. */
2722
2723struct btrfs_raid_bio *
2724raid56_alloc_missing_rbio(struct btrfs_fs_info *fs_info, struct bio *bio,
2725 struct btrfs_bio *bbio, u64 length)
2726{
2727 struct btrfs_raid_bio *rbio;
2728
2729 rbio = alloc_rbio(fs_info, bbio, length);
2730 if (IS_ERR(rbio))
2731 return NULL;
2732
2733 rbio->operation = BTRFS_RBIO_REBUILD_MISSING;
2734 bio_list_add(&rbio->bio_list, bio);
2735 /*
2736 * This is a special bio which is used to hold the completion handler
2737 * and make the scrub rbio is similar to the other types
2738 */
2739 ASSERT(!bio->bi_iter.bi_size);
2740
2741 rbio->faila = find_logical_bio_stripe(rbio, bio);
2742 if (rbio->faila == -1) {
2743 BUG();
2744 kfree(rbio);
2745 return NULL;
2746 }
2747
2748 /*
2749 * When we get bbio, we have already increased bio_counter, record it
2750 * so we can free it at rbio_orig_end_io()
2751 */
2752 rbio->generic_bio_cnt = 1;
2753
2754 return rbio;
2755}
2756
2757void raid56_submit_missing_rbio(struct btrfs_raid_bio *rbio)
2758{
2759 if (!lock_stripe_add(rbio))
2760 start_async_work(rbio, read_rebuild_work);
2761}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2012 Fusion-io All rights reserved.
4 * Copyright (C) 2012 Intel Corp. All rights reserved.
5 */
6
7#include <linux/sched.h>
8#include <linux/bio.h>
9#include <linux/slab.h>
10#include <linux/blkdev.h>
11#include <linux/raid/pq.h>
12#include <linux/hash.h>
13#include <linux/list_sort.h>
14#include <linux/raid/xor.h>
15#include <linux/mm.h>
16#include "misc.h"
17#include "ctree.h"
18#include "disk-io.h"
19#include "volumes.h"
20#include "raid56.h"
21#include "async-thread.h"
22
23/* set when additional merges to this rbio are not allowed */
24#define RBIO_RMW_LOCKED_BIT 1
25
26/*
27 * set when this rbio is sitting in the hash, but it is just a cache
28 * of past RMW
29 */
30#define RBIO_CACHE_BIT 2
31
32/*
33 * set when it is safe to trust the stripe_pages for caching
34 */
35#define RBIO_CACHE_READY_BIT 3
36
37#define RBIO_CACHE_SIZE 1024
38
39#define BTRFS_STRIPE_HASH_TABLE_BITS 11
40
41/* Used by the raid56 code to lock stripes for read/modify/write */
42struct btrfs_stripe_hash {
43 struct list_head hash_list;
44 spinlock_t lock;
45};
46
47/* Used by the raid56 code to lock stripes for read/modify/write */
48struct btrfs_stripe_hash_table {
49 struct list_head stripe_cache;
50 spinlock_t cache_lock;
51 int cache_size;
52 struct btrfs_stripe_hash table[];
53};
54
55enum btrfs_rbio_ops {
56 BTRFS_RBIO_WRITE,
57 BTRFS_RBIO_READ_REBUILD,
58 BTRFS_RBIO_PARITY_SCRUB,
59 BTRFS_RBIO_REBUILD_MISSING,
60};
61
62struct btrfs_raid_bio {
63 struct btrfs_fs_info *fs_info;
64 struct btrfs_bio *bbio;
65
66 /* while we're doing rmw on a stripe
67 * we put it into a hash table so we can
68 * lock the stripe and merge more rbios
69 * into it.
70 */
71 struct list_head hash_list;
72
73 /*
74 * LRU list for the stripe cache
75 */
76 struct list_head stripe_cache;
77
78 /*
79 * for scheduling work in the helper threads
80 */
81 struct btrfs_work work;
82
83 /*
84 * bio list and bio_list_lock are used
85 * to add more bios into the stripe
86 * in hopes of avoiding the full rmw
87 */
88 struct bio_list bio_list;
89 spinlock_t bio_list_lock;
90
91 /* also protected by the bio_list_lock, the
92 * plug list is used by the plugging code
93 * to collect partial bios while plugged. The
94 * stripe locking code also uses it to hand off
95 * the stripe lock to the next pending IO
96 */
97 struct list_head plug_list;
98
99 /*
100 * flags that tell us if it is safe to
101 * merge with this bio
102 */
103 unsigned long flags;
104
105 /* size of each individual stripe on disk */
106 int stripe_len;
107
108 /* number of data stripes (no p/q) */
109 int nr_data;
110
111 int real_stripes;
112
113 int stripe_npages;
114 /*
115 * set if we're doing a parity rebuild
116 * for a read from higher up, which is handled
117 * differently from a parity rebuild as part of
118 * rmw
119 */
120 enum btrfs_rbio_ops operation;
121
122 /* first bad stripe */
123 int faila;
124
125 /* second bad stripe (for raid6 use) */
126 int failb;
127
128 int scrubp;
129 /*
130 * number of pages needed to represent the full
131 * stripe
132 */
133 int nr_pages;
134
135 /*
136 * size of all the bios in the bio_list. This
137 * helps us decide if the rbio maps to a full
138 * stripe or not
139 */
140 int bio_list_bytes;
141
142 int generic_bio_cnt;
143
144 refcount_t refs;
145
146 atomic_t stripes_pending;
147
148 atomic_t error;
149 /*
150 * these are two arrays of pointers. We allocate the
151 * rbio big enough to hold them both and setup their
152 * locations when the rbio is allocated
153 */
154
155 /* pointers to pages that we allocated for
156 * reading/writing stripes directly from the disk (including P/Q)
157 */
158 struct page **stripe_pages;
159
160 /*
161 * pointers to the pages in the bio_list. Stored
162 * here for faster lookup
163 */
164 struct page **bio_pages;
165
166 /*
167 * bitmap to record which horizontal stripe has data
168 */
169 unsigned long *dbitmap;
170
171 /* allocated with real_stripes-many pointers for finish_*() calls */
172 void **finish_pointers;
173
174 /* allocated with stripe_npages-many bits for finish_*() calls */
175 unsigned long *finish_pbitmap;
176};
177
178static int __raid56_parity_recover(struct btrfs_raid_bio *rbio);
179static noinline void finish_rmw(struct btrfs_raid_bio *rbio);
180static void rmw_work(struct btrfs_work *work);
181static void read_rebuild_work(struct btrfs_work *work);
182static int fail_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio);
183static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed);
184static void __free_raid_bio(struct btrfs_raid_bio *rbio);
185static void index_rbio_pages(struct btrfs_raid_bio *rbio);
186static int alloc_rbio_pages(struct btrfs_raid_bio *rbio);
187
188static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
189 int need_check);
190static void scrub_parity_work(struct btrfs_work *work);
191
192static void start_async_work(struct btrfs_raid_bio *rbio, btrfs_func_t work_func)
193{
194 btrfs_init_work(&rbio->work, work_func, NULL, NULL);
195 btrfs_queue_work(rbio->fs_info->rmw_workers, &rbio->work);
196}
197
198/*
199 * the stripe hash table is used for locking, and to collect
200 * bios in hopes of making a full stripe
201 */
202int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info)
203{
204 struct btrfs_stripe_hash_table *table;
205 struct btrfs_stripe_hash_table *x;
206 struct btrfs_stripe_hash *cur;
207 struct btrfs_stripe_hash *h;
208 int num_entries = 1 << BTRFS_STRIPE_HASH_TABLE_BITS;
209 int i;
210
211 if (info->stripe_hash_table)
212 return 0;
213
214 /*
215 * The table is large, starting with order 4 and can go as high as
216 * order 7 in case lock debugging is turned on.
217 *
218 * Try harder to allocate and fallback to vmalloc to lower the chance
219 * of a failing mount.
220 */
221 table = kvzalloc(struct_size(table, table, num_entries), GFP_KERNEL);
222 if (!table)
223 return -ENOMEM;
224
225 spin_lock_init(&table->cache_lock);
226 INIT_LIST_HEAD(&table->stripe_cache);
227
228 h = table->table;
229
230 for (i = 0; i < num_entries; i++) {
231 cur = h + i;
232 INIT_LIST_HEAD(&cur->hash_list);
233 spin_lock_init(&cur->lock);
234 }
235
236 x = cmpxchg(&info->stripe_hash_table, NULL, table);
237 kvfree(x);
238 return 0;
239}
240
241/*
242 * caching an rbio means to copy anything from the
243 * bio_pages array into the stripe_pages array. We
244 * use the page uptodate bit in the stripe cache array
245 * to indicate if it has valid data
246 *
247 * once the caching is done, we set the cache ready
248 * bit.
249 */
250static void cache_rbio_pages(struct btrfs_raid_bio *rbio)
251{
252 int i;
253 int ret;
254
255 ret = alloc_rbio_pages(rbio);
256 if (ret)
257 return;
258
259 for (i = 0; i < rbio->nr_pages; i++) {
260 if (!rbio->bio_pages[i])
261 continue;
262
263 copy_highpage(rbio->stripe_pages[i], rbio->bio_pages[i]);
264 SetPageUptodate(rbio->stripe_pages[i]);
265 }
266 set_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
267}
268
269/*
270 * we hash on the first logical address of the stripe
271 */
272static int rbio_bucket(struct btrfs_raid_bio *rbio)
273{
274 u64 num = rbio->bbio->raid_map[0];
275
276 /*
277 * we shift down quite a bit. We're using byte
278 * addressing, and most of the lower bits are zeros.
279 * This tends to upset hash_64, and it consistently
280 * returns just one or two different values.
281 *
282 * shifting off the lower bits fixes things.
283 */
284 return hash_64(num >> 16, BTRFS_STRIPE_HASH_TABLE_BITS);
285}
286
287/*
288 * stealing an rbio means taking all the uptodate pages from the stripe
289 * array in the source rbio and putting them into the destination rbio
290 */
291static void steal_rbio(struct btrfs_raid_bio *src, struct btrfs_raid_bio *dest)
292{
293 int i;
294 struct page *s;
295 struct page *d;
296
297 if (!test_bit(RBIO_CACHE_READY_BIT, &src->flags))
298 return;
299
300 for (i = 0; i < dest->nr_pages; i++) {
301 s = src->stripe_pages[i];
302 if (!s || !PageUptodate(s)) {
303 continue;
304 }
305
306 d = dest->stripe_pages[i];
307 if (d)
308 __free_page(d);
309
310 dest->stripe_pages[i] = s;
311 src->stripe_pages[i] = NULL;
312 }
313}
314
315/*
316 * merging means we take the bio_list from the victim and
317 * splice it into the destination. The victim should
318 * be discarded afterwards.
319 *
320 * must be called with dest->rbio_list_lock held
321 */
322static void merge_rbio(struct btrfs_raid_bio *dest,
323 struct btrfs_raid_bio *victim)
324{
325 bio_list_merge(&dest->bio_list, &victim->bio_list);
326 dest->bio_list_bytes += victim->bio_list_bytes;
327 dest->generic_bio_cnt += victim->generic_bio_cnt;
328 bio_list_init(&victim->bio_list);
329}
330
331/*
332 * used to prune items that are in the cache. The caller
333 * must hold the hash table lock.
334 */
335static void __remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
336{
337 int bucket = rbio_bucket(rbio);
338 struct btrfs_stripe_hash_table *table;
339 struct btrfs_stripe_hash *h;
340 int freeit = 0;
341
342 /*
343 * check the bit again under the hash table lock.
344 */
345 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
346 return;
347
348 table = rbio->fs_info->stripe_hash_table;
349 h = table->table + bucket;
350
351 /* hold the lock for the bucket because we may be
352 * removing it from the hash table
353 */
354 spin_lock(&h->lock);
355
356 /*
357 * hold the lock for the bio list because we need
358 * to make sure the bio list is empty
359 */
360 spin_lock(&rbio->bio_list_lock);
361
362 if (test_and_clear_bit(RBIO_CACHE_BIT, &rbio->flags)) {
363 list_del_init(&rbio->stripe_cache);
364 table->cache_size -= 1;
365 freeit = 1;
366
367 /* if the bio list isn't empty, this rbio is
368 * still involved in an IO. We take it out
369 * of the cache list, and drop the ref that
370 * was held for the list.
371 *
372 * If the bio_list was empty, we also remove
373 * the rbio from the hash_table, and drop
374 * the corresponding ref
375 */
376 if (bio_list_empty(&rbio->bio_list)) {
377 if (!list_empty(&rbio->hash_list)) {
378 list_del_init(&rbio->hash_list);
379 refcount_dec(&rbio->refs);
380 BUG_ON(!list_empty(&rbio->plug_list));
381 }
382 }
383 }
384
385 spin_unlock(&rbio->bio_list_lock);
386 spin_unlock(&h->lock);
387
388 if (freeit)
389 __free_raid_bio(rbio);
390}
391
392/*
393 * prune a given rbio from the cache
394 */
395static void remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
396{
397 struct btrfs_stripe_hash_table *table;
398 unsigned long flags;
399
400 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
401 return;
402
403 table = rbio->fs_info->stripe_hash_table;
404
405 spin_lock_irqsave(&table->cache_lock, flags);
406 __remove_rbio_from_cache(rbio);
407 spin_unlock_irqrestore(&table->cache_lock, flags);
408}
409
410/*
411 * remove everything in the cache
412 */
413static void btrfs_clear_rbio_cache(struct btrfs_fs_info *info)
414{
415 struct btrfs_stripe_hash_table *table;
416 unsigned long flags;
417 struct btrfs_raid_bio *rbio;
418
419 table = info->stripe_hash_table;
420
421 spin_lock_irqsave(&table->cache_lock, flags);
422 while (!list_empty(&table->stripe_cache)) {
423 rbio = list_entry(table->stripe_cache.next,
424 struct btrfs_raid_bio,
425 stripe_cache);
426 __remove_rbio_from_cache(rbio);
427 }
428 spin_unlock_irqrestore(&table->cache_lock, flags);
429}
430
431/*
432 * remove all cached entries and free the hash table
433 * used by unmount
434 */
435void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info)
436{
437 if (!info->stripe_hash_table)
438 return;
439 btrfs_clear_rbio_cache(info);
440 kvfree(info->stripe_hash_table);
441 info->stripe_hash_table = NULL;
442}
443
444/*
445 * insert an rbio into the stripe cache. It
446 * must have already been prepared by calling
447 * cache_rbio_pages
448 *
449 * If this rbio was already cached, it gets
450 * moved to the front of the lru.
451 *
452 * If the size of the rbio cache is too big, we
453 * prune an item.
454 */
455static void cache_rbio(struct btrfs_raid_bio *rbio)
456{
457 struct btrfs_stripe_hash_table *table;
458 unsigned long flags;
459
460 if (!test_bit(RBIO_CACHE_READY_BIT, &rbio->flags))
461 return;
462
463 table = rbio->fs_info->stripe_hash_table;
464
465 spin_lock_irqsave(&table->cache_lock, flags);
466 spin_lock(&rbio->bio_list_lock);
467
468 /* bump our ref if we were not in the list before */
469 if (!test_and_set_bit(RBIO_CACHE_BIT, &rbio->flags))
470 refcount_inc(&rbio->refs);
471
472 if (!list_empty(&rbio->stripe_cache)){
473 list_move(&rbio->stripe_cache, &table->stripe_cache);
474 } else {
475 list_add(&rbio->stripe_cache, &table->stripe_cache);
476 table->cache_size += 1;
477 }
478
479 spin_unlock(&rbio->bio_list_lock);
480
481 if (table->cache_size > RBIO_CACHE_SIZE) {
482 struct btrfs_raid_bio *found;
483
484 found = list_entry(table->stripe_cache.prev,
485 struct btrfs_raid_bio,
486 stripe_cache);
487
488 if (found != rbio)
489 __remove_rbio_from_cache(found);
490 }
491
492 spin_unlock_irqrestore(&table->cache_lock, flags);
493}
494
495/*
496 * helper function to run the xor_blocks api. It is only
497 * able to do MAX_XOR_BLOCKS at a time, so we need to
498 * loop through.
499 */
500static void run_xor(void **pages, int src_cnt, ssize_t len)
501{
502 int src_off = 0;
503 int xor_src_cnt = 0;
504 void *dest = pages[src_cnt];
505
506 while(src_cnt > 0) {
507 xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS);
508 xor_blocks(xor_src_cnt, len, dest, pages + src_off);
509
510 src_cnt -= xor_src_cnt;
511 src_off += xor_src_cnt;
512 }
513}
514
515/*
516 * Returns true if the bio list inside this rbio covers an entire stripe (no
517 * rmw required).
518 */
519static int rbio_is_full(struct btrfs_raid_bio *rbio)
520{
521 unsigned long flags;
522 unsigned long size = rbio->bio_list_bytes;
523 int ret = 1;
524
525 spin_lock_irqsave(&rbio->bio_list_lock, flags);
526 if (size != rbio->nr_data * rbio->stripe_len)
527 ret = 0;
528 BUG_ON(size > rbio->nr_data * rbio->stripe_len);
529 spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
530
531 return ret;
532}
533
534/*
535 * returns 1 if it is safe to merge two rbios together.
536 * The merging is safe if the two rbios correspond to
537 * the same stripe and if they are both going in the same
538 * direction (read vs write), and if neither one is
539 * locked for final IO
540 *
541 * The caller is responsible for locking such that
542 * rmw_locked is safe to test
543 */
544static int rbio_can_merge(struct btrfs_raid_bio *last,
545 struct btrfs_raid_bio *cur)
546{
547 if (test_bit(RBIO_RMW_LOCKED_BIT, &last->flags) ||
548 test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags))
549 return 0;
550
551 /*
552 * we can't merge with cached rbios, since the
553 * idea is that when we merge the destination
554 * rbio is going to run our IO for us. We can
555 * steal from cached rbios though, other functions
556 * handle that.
557 */
558 if (test_bit(RBIO_CACHE_BIT, &last->flags) ||
559 test_bit(RBIO_CACHE_BIT, &cur->flags))
560 return 0;
561
562 if (last->bbio->raid_map[0] !=
563 cur->bbio->raid_map[0])
564 return 0;
565
566 /* we can't merge with different operations */
567 if (last->operation != cur->operation)
568 return 0;
569 /*
570 * We've need read the full stripe from the drive.
571 * check and repair the parity and write the new results.
572 *
573 * We're not allowed to add any new bios to the
574 * bio list here, anyone else that wants to
575 * change this stripe needs to do their own rmw.
576 */
577 if (last->operation == BTRFS_RBIO_PARITY_SCRUB)
578 return 0;
579
580 if (last->operation == BTRFS_RBIO_REBUILD_MISSING)
581 return 0;
582
583 if (last->operation == BTRFS_RBIO_READ_REBUILD) {
584 int fa = last->faila;
585 int fb = last->failb;
586 int cur_fa = cur->faila;
587 int cur_fb = cur->failb;
588
589 if (last->faila >= last->failb) {
590 fa = last->failb;
591 fb = last->faila;
592 }
593
594 if (cur->faila >= cur->failb) {
595 cur_fa = cur->failb;
596 cur_fb = cur->faila;
597 }
598
599 if (fa != cur_fa || fb != cur_fb)
600 return 0;
601 }
602 return 1;
603}
604
605static int rbio_stripe_page_index(struct btrfs_raid_bio *rbio, int stripe,
606 int index)
607{
608 return stripe * rbio->stripe_npages + index;
609}
610
611/*
612 * these are just the pages from the rbio array, not from anything
613 * the FS sent down to us
614 */
615static struct page *rbio_stripe_page(struct btrfs_raid_bio *rbio, int stripe,
616 int index)
617{
618 return rbio->stripe_pages[rbio_stripe_page_index(rbio, stripe, index)];
619}
620
621/*
622 * helper to index into the pstripe
623 */
624static struct page *rbio_pstripe_page(struct btrfs_raid_bio *rbio, int index)
625{
626 return rbio_stripe_page(rbio, rbio->nr_data, index);
627}
628
629/*
630 * helper to index into the qstripe, returns null
631 * if there is no qstripe
632 */
633static struct page *rbio_qstripe_page(struct btrfs_raid_bio *rbio, int index)
634{
635 if (rbio->nr_data + 1 == rbio->real_stripes)
636 return NULL;
637 return rbio_stripe_page(rbio, rbio->nr_data + 1, index);
638}
639
640/*
641 * The first stripe in the table for a logical address
642 * has the lock. rbios are added in one of three ways:
643 *
644 * 1) Nobody has the stripe locked yet. The rbio is given
645 * the lock and 0 is returned. The caller must start the IO
646 * themselves.
647 *
648 * 2) Someone has the stripe locked, but we're able to merge
649 * with the lock owner. The rbio is freed and the IO will
650 * start automatically along with the existing rbio. 1 is returned.
651 *
652 * 3) Someone has the stripe locked, but we're not able to merge.
653 * The rbio is added to the lock owner's plug list, or merged into
654 * an rbio already on the plug list. When the lock owner unlocks,
655 * the next rbio on the list is run and the IO is started automatically.
656 * 1 is returned
657 *
658 * If we return 0, the caller still owns the rbio and must continue with
659 * IO submission. If we return 1, the caller must assume the rbio has
660 * already been freed.
661 */
662static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
663{
664 struct btrfs_stripe_hash *h;
665 struct btrfs_raid_bio *cur;
666 struct btrfs_raid_bio *pending;
667 unsigned long flags;
668 struct btrfs_raid_bio *freeit = NULL;
669 struct btrfs_raid_bio *cache_drop = NULL;
670 int ret = 0;
671
672 h = rbio->fs_info->stripe_hash_table->table + rbio_bucket(rbio);
673
674 spin_lock_irqsave(&h->lock, flags);
675 list_for_each_entry(cur, &h->hash_list, hash_list) {
676 if (cur->bbio->raid_map[0] != rbio->bbio->raid_map[0])
677 continue;
678
679 spin_lock(&cur->bio_list_lock);
680
681 /* Can we steal this cached rbio's pages? */
682 if (bio_list_empty(&cur->bio_list) &&
683 list_empty(&cur->plug_list) &&
684 test_bit(RBIO_CACHE_BIT, &cur->flags) &&
685 !test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) {
686 list_del_init(&cur->hash_list);
687 refcount_dec(&cur->refs);
688
689 steal_rbio(cur, rbio);
690 cache_drop = cur;
691 spin_unlock(&cur->bio_list_lock);
692
693 goto lockit;
694 }
695
696 /* Can we merge into the lock owner? */
697 if (rbio_can_merge(cur, rbio)) {
698 merge_rbio(cur, rbio);
699 spin_unlock(&cur->bio_list_lock);
700 freeit = rbio;
701 ret = 1;
702 goto out;
703 }
704
705
706 /*
707 * We couldn't merge with the running rbio, see if we can merge
708 * with the pending ones. We don't have to check for rmw_locked
709 * because there is no way they are inside finish_rmw right now
710 */
711 list_for_each_entry(pending, &cur->plug_list, plug_list) {
712 if (rbio_can_merge(pending, rbio)) {
713 merge_rbio(pending, rbio);
714 spin_unlock(&cur->bio_list_lock);
715 freeit = rbio;
716 ret = 1;
717 goto out;
718 }
719 }
720
721 /*
722 * No merging, put us on the tail of the plug list, our rbio
723 * will be started with the currently running rbio unlocks
724 */
725 list_add_tail(&rbio->plug_list, &cur->plug_list);
726 spin_unlock(&cur->bio_list_lock);
727 ret = 1;
728 goto out;
729 }
730lockit:
731 refcount_inc(&rbio->refs);
732 list_add(&rbio->hash_list, &h->hash_list);
733out:
734 spin_unlock_irqrestore(&h->lock, flags);
735 if (cache_drop)
736 remove_rbio_from_cache(cache_drop);
737 if (freeit)
738 __free_raid_bio(freeit);
739 return ret;
740}
741
742/*
743 * called as rmw or parity rebuild is completed. If the plug list has more
744 * rbios waiting for this stripe, the next one on the list will be started
745 */
746static noinline void unlock_stripe(struct btrfs_raid_bio *rbio)
747{
748 int bucket;
749 struct btrfs_stripe_hash *h;
750 unsigned long flags;
751 int keep_cache = 0;
752
753 bucket = rbio_bucket(rbio);
754 h = rbio->fs_info->stripe_hash_table->table + bucket;
755
756 if (list_empty(&rbio->plug_list))
757 cache_rbio(rbio);
758
759 spin_lock_irqsave(&h->lock, flags);
760 spin_lock(&rbio->bio_list_lock);
761
762 if (!list_empty(&rbio->hash_list)) {
763 /*
764 * if we're still cached and there is no other IO
765 * to perform, just leave this rbio here for others
766 * to steal from later
767 */
768 if (list_empty(&rbio->plug_list) &&
769 test_bit(RBIO_CACHE_BIT, &rbio->flags)) {
770 keep_cache = 1;
771 clear_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
772 BUG_ON(!bio_list_empty(&rbio->bio_list));
773 goto done;
774 }
775
776 list_del_init(&rbio->hash_list);
777 refcount_dec(&rbio->refs);
778
779 /*
780 * we use the plug list to hold all the rbios
781 * waiting for the chance to lock this stripe.
782 * hand the lock over to one of them.
783 */
784 if (!list_empty(&rbio->plug_list)) {
785 struct btrfs_raid_bio *next;
786 struct list_head *head = rbio->plug_list.next;
787
788 next = list_entry(head, struct btrfs_raid_bio,
789 plug_list);
790
791 list_del_init(&rbio->plug_list);
792
793 list_add(&next->hash_list, &h->hash_list);
794 refcount_inc(&next->refs);
795 spin_unlock(&rbio->bio_list_lock);
796 spin_unlock_irqrestore(&h->lock, flags);
797
798 if (next->operation == BTRFS_RBIO_READ_REBUILD)
799 start_async_work(next, read_rebuild_work);
800 else if (next->operation == BTRFS_RBIO_REBUILD_MISSING) {
801 steal_rbio(rbio, next);
802 start_async_work(next, read_rebuild_work);
803 } else if (next->operation == BTRFS_RBIO_WRITE) {
804 steal_rbio(rbio, next);
805 start_async_work(next, rmw_work);
806 } else if (next->operation == BTRFS_RBIO_PARITY_SCRUB) {
807 steal_rbio(rbio, next);
808 start_async_work(next, scrub_parity_work);
809 }
810
811 goto done_nolock;
812 }
813 }
814done:
815 spin_unlock(&rbio->bio_list_lock);
816 spin_unlock_irqrestore(&h->lock, flags);
817
818done_nolock:
819 if (!keep_cache)
820 remove_rbio_from_cache(rbio);
821}
822
823static void __free_raid_bio(struct btrfs_raid_bio *rbio)
824{
825 int i;
826
827 if (!refcount_dec_and_test(&rbio->refs))
828 return;
829
830 WARN_ON(!list_empty(&rbio->stripe_cache));
831 WARN_ON(!list_empty(&rbio->hash_list));
832 WARN_ON(!bio_list_empty(&rbio->bio_list));
833
834 for (i = 0; i < rbio->nr_pages; i++) {
835 if (rbio->stripe_pages[i]) {
836 __free_page(rbio->stripe_pages[i]);
837 rbio->stripe_pages[i] = NULL;
838 }
839 }
840
841 btrfs_put_bbio(rbio->bbio);
842 kfree(rbio);
843}
844
845static void rbio_endio_bio_list(struct bio *cur, blk_status_t err)
846{
847 struct bio *next;
848
849 while (cur) {
850 next = cur->bi_next;
851 cur->bi_next = NULL;
852 cur->bi_status = err;
853 bio_endio(cur);
854 cur = next;
855 }
856}
857
858/*
859 * this frees the rbio and runs through all the bios in the
860 * bio_list and calls end_io on them
861 */
862static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, blk_status_t err)
863{
864 struct bio *cur = bio_list_get(&rbio->bio_list);
865 struct bio *extra;
866
867 if (rbio->generic_bio_cnt)
868 btrfs_bio_counter_sub(rbio->fs_info, rbio->generic_bio_cnt);
869
870 /*
871 * At this moment, rbio->bio_list is empty, however since rbio does not
872 * always have RBIO_RMW_LOCKED_BIT set and rbio is still linked on the
873 * hash list, rbio may be merged with others so that rbio->bio_list
874 * becomes non-empty.
875 * Once unlock_stripe() is done, rbio->bio_list will not be updated any
876 * more and we can call bio_endio() on all queued bios.
877 */
878 unlock_stripe(rbio);
879 extra = bio_list_get(&rbio->bio_list);
880 __free_raid_bio(rbio);
881
882 rbio_endio_bio_list(cur, err);
883 if (extra)
884 rbio_endio_bio_list(extra, err);
885}
886
887/*
888 * end io function used by finish_rmw. When we finally
889 * get here, we've written a full stripe
890 */
891static void raid_write_end_io(struct bio *bio)
892{
893 struct btrfs_raid_bio *rbio = bio->bi_private;
894 blk_status_t err = bio->bi_status;
895 int max_errors;
896
897 if (err)
898 fail_bio_stripe(rbio, bio);
899
900 bio_put(bio);
901
902 if (!atomic_dec_and_test(&rbio->stripes_pending))
903 return;
904
905 err = BLK_STS_OK;
906
907 /* OK, we have read all the stripes we need to. */
908 max_errors = (rbio->operation == BTRFS_RBIO_PARITY_SCRUB) ?
909 0 : rbio->bbio->max_errors;
910 if (atomic_read(&rbio->error) > max_errors)
911 err = BLK_STS_IOERR;
912
913 rbio_orig_end_io(rbio, err);
914}
915
916/*
917 * the read/modify/write code wants to use the original bio for
918 * any pages it included, and then use the rbio for everything
919 * else. This function decides if a given index (stripe number)
920 * and page number in that stripe fall inside the original bio
921 * or the rbio.
922 *
923 * if you set bio_list_only, you'll get a NULL back for any ranges
924 * that are outside the bio_list
925 *
926 * This doesn't take any refs on anything, you get a bare page pointer
927 * and the caller must bump refs as required.
928 *
929 * You must call index_rbio_pages once before you can trust
930 * the answers from this function.
931 */
932static struct page *page_in_rbio(struct btrfs_raid_bio *rbio,
933 int index, int pagenr, int bio_list_only)
934{
935 int chunk_page;
936 struct page *p = NULL;
937
938 chunk_page = index * (rbio->stripe_len >> PAGE_SHIFT) + pagenr;
939
940 spin_lock_irq(&rbio->bio_list_lock);
941 p = rbio->bio_pages[chunk_page];
942 spin_unlock_irq(&rbio->bio_list_lock);
943
944 if (p || bio_list_only)
945 return p;
946
947 return rbio->stripe_pages[chunk_page];
948}
949
950/*
951 * number of pages we need for the entire stripe across all the
952 * drives
953 */
954static unsigned long rbio_nr_pages(unsigned long stripe_len, int nr_stripes)
955{
956 return DIV_ROUND_UP(stripe_len, PAGE_SIZE) * nr_stripes;
957}
958
959/*
960 * allocation and initial setup for the btrfs_raid_bio. Not
961 * this does not allocate any pages for rbio->pages.
962 */
963static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info,
964 struct btrfs_bio *bbio,
965 u64 stripe_len)
966{
967 struct btrfs_raid_bio *rbio;
968 int nr_data = 0;
969 int real_stripes = bbio->num_stripes - bbio->num_tgtdevs;
970 int num_pages = rbio_nr_pages(stripe_len, real_stripes);
971 int stripe_npages = DIV_ROUND_UP(stripe_len, PAGE_SIZE);
972 void *p;
973
974 rbio = kzalloc(sizeof(*rbio) +
975 sizeof(*rbio->stripe_pages) * num_pages +
976 sizeof(*rbio->bio_pages) * num_pages +
977 sizeof(*rbio->finish_pointers) * real_stripes +
978 sizeof(*rbio->dbitmap) * BITS_TO_LONGS(stripe_npages) +
979 sizeof(*rbio->finish_pbitmap) *
980 BITS_TO_LONGS(stripe_npages),
981 GFP_NOFS);
982 if (!rbio)
983 return ERR_PTR(-ENOMEM);
984
985 bio_list_init(&rbio->bio_list);
986 INIT_LIST_HEAD(&rbio->plug_list);
987 spin_lock_init(&rbio->bio_list_lock);
988 INIT_LIST_HEAD(&rbio->stripe_cache);
989 INIT_LIST_HEAD(&rbio->hash_list);
990 rbio->bbio = bbio;
991 rbio->fs_info = fs_info;
992 rbio->stripe_len = stripe_len;
993 rbio->nr_pages = num_pages;
994 rbio->real_stripes = real_stripes;
995 rbio->stripe_npages = stripe_npages;
996 rbio->faila = -1;
997 rbio->failb = -1;
998 refcount_set(&rbio->refs, 1);
999 atomic_set(&rbio->error, 0);
1000 atomic_set(&rbio->stripes_pending, 0);
1001
1002 /*
1003 * the stripe_pages, bio_pages, etc arrays point to the extra
1004 * memory we allocated past the end of the rbio
1005 */
1006 p = rbio + 1;
1007#define CONSUME_ALLOC(ptr, count) do { \
1008 ptr = p; \
1009 p = (unsigned char *)p + sizeof(*(ptr)) * (count); \
1010 } while (0)
1011 CONSUME_ALLOC(rbio->stripe_pages, num_pages);
1012 CONSUME_ALLOC(rbio->bio_pages, num_pages);
1013 CONSUME_ALLOC(rbio->finish_pointers, real_stripes);
1014 CONSUME_ALLOC(rbio->dbitmap, BITS_TO_LONGS(stripe_npages));
1015 CONSUME_ALLOC(rbio->finish_pbitmap, BITS_TO_LONGS(stripe_npages));
1016#undef CONSUME_ALLOC
1017
1018 if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID5)
1019 nr_data = real_stripes - 1;
1020 else if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID6)
1021 nr_data = real_stripes - 2;
1022 else
1023 BUG();
1024
1025 rbio->nr_data = nr_data;
1026 return rbio;
1027}
1028
1029/* allocate pages for all the stripes in the bio, including parity */
1030static int alloc_rbio_pages(struct btrfs_raid_bio *rbio)
1031{
1032 int i;
1033 struct page *page;
1034
1035 for (i = 0; i < rbio->nr_pages; i++) {
1036 if (rbio->stripe_pages[i])
1037 continue;
1038 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1039 if (!page)
1040 return -ENOMEM;
1041 rbio->stripe_pages[i] = page;
1042 }
1043 return 0;
1044}
1045
1046/* only allocate pages for p/q stripes */
1047static int alloc_rbio_parity_pages(struct btrfs_raid_bio *rbio)
1048{
1049 int i;
1050 struct page *page;
1051
1052 i = rbio_stripe_page_index(rbio, rbio->nr_data, 0);
1053
1054 for (; i < rbio->nr_pages; i++) {
1055 if (rbio->stripe_pages[i])
1056 continue;
1057 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1058 if (!page)
1059 return -ENOMEM;
1060 rbio->stripe_pages[i] = page;
1061 }
1062 return 0;
1063}
1064
1065/*
1066 * add a single page from a specific stripe into our list of bios for IO
1067 * this will try to merge into existing bios if possible, and returns
1068 * zero if all went well.
1069 */
1070static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
1071 struct bio_list *bio_list,
1072 struct page *page,
1073 int stripe_nr,
1074 unsigned long page_index,
1075 unsigned long bio_max_len)
1076{
1077 struct bio *last = bio_list->tail;
1078 int ret;
1079 struct bio *bio;
1080 struct btrfs_bio_stripe *stripe;
1081 u64 disk_start;
1082
1083 stripe = &rbio->bbio->stripes[stripe_nr];
1084 disk_start = stripe->physical + (page_index << PAGE_SHIFT);
1085
1086 /* if the device is missing, just fail this stripe */
1087 if (!stripe->dev->bdev)
1088 return fail_rbio_index(rbio, stripe_nr);
1089
1090 /* see if we can add this page onto our existing bio */
1091 if (last) {
1092 u64 last_end = last->bi_iter.bi_sector << 9;
1093 last_end += last->bi_iter.bi_size;
1094
1095 /*
1096 * we can't merge these if they are from different
1097 * devices or if they are not contiguous
1098 */
1099 if (last_end == disk_start && !last->bi_status &&
1100 last->bi_bdev == stripe->dev->bdev) {
1101 ret = bio_add_page(last, page, PAGE_SIZE, 0);
1102 if (ret == PAGE_SIZE)
1103 return 0;
1104 }
1105 }
1106
1107 /* put a new bio on the list */
1108 bio = btrfs_io_bio_alloc(bio_max_len >> PAGE_SHIFT ?: 1);
1109 btrfs_io_bio(bio)->device = stripe->dev;
1110 bio->bi_iter.bi_size = 0;
1111 bio_set_dev(bio, stripe->dev->bdev);
1112 bio->bi_iter.bi_sector = disk_start >> 9;
1113
1114 bio_add_page(bio, page, PAGE_SIZE, 0);
1115 bio_list_add(bio_list, bio);
1116 return 0;
1117}
1118
1119/*
1120 * while we're doing the read/modify/write cycle, we could
1121 * have errors in reading pages off the disk. This checks
1122 * for errors and if we're not able to read the page it'll
1123 * trigger parity reconstruction. The rmw will be finished
1124 * after we've reconstructed the failed stripes
1125 */
1126static void validate_rbio_for_rmw(struct btrfs_raid_bio *rbio)
1127{
1128 if (rbio->faila >= 0 || rbio->failb >= 0) {
1129 BUG_ON(rbio->faila == rbio->real_stripes - 1);
1130 __raid56_parity_recover(rbio);
1131 } else {
1132 finish_rmw(rbio);
1133 }
1134}
1135
1136/*
1137 * helper function to walk our bio list and populate the bio_pages array with
1138 * the result. This seems expensive, but it is faster than constantly
1139 * searching through the bio list as we setup the IO in finish_rmw or stripe
1140 * reconstruction.
1141 *
1142 * This must be called before you trust the answers from page_in_rbio
1143 */
1144static void index_rbio_pages(struct btrfs_raid_bio *rbio)
1145{
1146 struct bio *bio;
1147 u64 start;
1148 unsigned long stripe_offset;
1149 unsigned long page_index;
1150
1151 spin_lock_irq(&rbio->bio_list_lock);
1152 bio_list_for_each(bio, &rbio->bio_list) {
1153 struct bio_vec bvec;
1154 struct bvec_iter iter;
1155 int i = 0;
1156
1157 start = bio->bi_iter.bi_sector << 9;
1158 stripe_offset = start - rbio->bbio->raid_map[0];
1159 page_index = stripe_offset >> PAGE_SHIFT;
1160
1161 if (bio_flagged(bio, BIO_CLONED))
1162 bio->bi_iter = btrfs_io_bio(bio)->iter;
1163
1164 bio_for_each_segment(bvec, bio, iter) {
1165 rbio->bio_pages[page_index + i] = bvec.bv_page;
1166 i++;
1167 }
1168 }
1169 spin_unlock_irq(&rbio->bio_list_lock);
1170}
1171
1172/*
1173 * this is called from one of two situations. We either
1174 * have a full stripe from the higher layers, or we've read all
1175 * the missing bits off disk.
1176 *
1177 * This will calculate the parity and then send down any
1178 * changed blocks.
1179 */
1180static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
1181{
1182 struct btrfs_bio *bbio = rbio->bbio;
1183 void **pointers = rbio->finish_pointers;
1184 int nr_data = rbio->nr_data;
1185 int stripe;
1186 int pagenr;
1187 bool has_qstripe;
1188 struct bio_list bio_list;
1189 struct bio *bio;
1190 int ret;
1191
1192 bio_list_init(&bio_list);
1193
1194 if (rbio->real_stripes - rbio->nr_data == 1)
1195 has_qstripe = false;
1196 else if (rbio->real_stripes - rbio->nr_data == 2)
1197 has_qstripe = true;
1198 else
1199 BUG();
1200
1201 /* at this point we either have a full stripe,
1202 * or we've read the full stripe from the drive.
1203 * recalculate the parity and write the new results.
1204 *
1205 * We're not allowed to add any new bios to the
1206 * bio list here, anyone else that wants to
1207 * change this stripe needs to do their own rmw.
1208 */
1209 spin_lock_irq(&rbio->bio_list_lock);
1210 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1211 spin_unlock_irq(&rbio->bio_list_lock);
1212
1213 atomic_set(&rbio->error, 0);
1214
1215 /*
1216 * now that we've set rmw_locked, run through the
1217 * bio list one last time and map the page pointers
1218 *
1219 * We don't cache full rbios because we're assuming
1220 * the higher layers are unlikely to use this area of
1221 * the disk again soon. If they do use it again,
1222 * hopefully they will send another full bio.
1223 */
1224 index_rbio_pages(rbio);
1225 if (!rbio_is_full(rbio))
1226 cache_rbio_pages(rbio);
1227 else
1228 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
1229
1230 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1231 struct page *p;
1232 /* first collect one page from each data stripe */
1233 for (stripe = 0; stripe < nr_data; stripe++) {
1234 p = page_in_rbio(rbio, stripe, pagenr, 0);
1235 pointers[stripe] = kmap_local_page(p);
1236 }
1237
1238 /* then add the parity stripe */
1239 p = rbio_pstripe_page(rbio, pagenr);
1240 SetPageUptodate(p);
1241 pointers[stripe++] = kmap_local_page(p);
1242
1243 if (has_qstripe) {
1244
1245 /*
1246 * raid6, add the qstripe and call the
1247 * library function to fill in our p/q
1248 */
1249 p = rbio_qstripe_page(rbio, pagenr);
1250 SetPageUptodate(p);
1251 pointers[stripe++] = kmap_local_page(p);
1252
1253 raid6_call.gen_syndrome(rbio->real_stripes, PAGE_SIZE,
1254 pointers);
1255 } else {
1256 /* raid5 */
1257 copy_page(pointers[nr_data], pointers[0]);
1258 run_xor(pointers + 1, nr_data - 1, PAGE_SIZE);
1259 }
1260 for (stripe = stripe - 1; stripe >= 0; stripe--)
1261 kunmap_local(pointers[stripe]);
1262 }
1263
1264 /*
1265 * time to start writing. Make bios for everything from the
1266 * higher layers (the bio_list in our rbio) and our p/q. Ignore
1267 * everything else.
1268 */
1269 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1270 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1271 struct page *page;
1272 if (stripe < rbio->nr_data) {
1273 page = page_in_rbio(rbio, stripe, pagenr, 1);
1274 if (!page)
1275 continue;
1276 } else {
1277 page = rbio_stripe_page(rbio, stripe, pagenr);
1278 }
1279
1280 ret = rbio_add_io_page(rbio, &bio_list,
1281 page, stripe, pagenr, rbio->stripe_len);
1282 if (ret)
1283 goto cleanup;
1284 }
1285 }
1286
1287 if (likely(!bbio->num_tgtdevs))
1288 goto write_data;
1289
1290 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1291 if (!bbio->tgtdev_map[stripe])
1292 continue;
1293
1294 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1295 struct page *page;
1296 if (stripe < rbio->nr_data) {
1297 page = page_in_rbio(rbio, stripe, pagenr, 1);
1298 if (!page)
1299 continue;
1300 } else {
1301 page = rbio_stripe_page(rbio, stripe, pagenr);
1302 }
1303
1304 ret = rbio_add_io_page(rbio, &bio_list, page,
1305 rbio->bbio->tgtdev_map[stripe],
1306 pagenr, rbio->stripe_len);
1307 if (ret)
1308 goto cleanup;
1309 }
1310 }
1311
1312write_data:
1313 atomic_set(&rbio->stripes_pending, bio_list_size(&bio_list));
1314 BUG_ON(atomic_read(&rbio->stripes_pending) == 0);
1315
1316 while ((bio = bio_list_pop(&bio_list))) {
1317 bio->bi_private = rbio;
1318 bio->bi_end_io = raid_write_end_io;
1319 bio->bi_opf = REQ_OP_WRITE;
1320
1321 submit_bio(bio);
1322 }
1323 return;
1324
1325cleanup:
1326 rbio_orig_end_io(rbio, BLK_STS_IOERR);
1327
1328 while ((bio = bio_list_pop(&bio_list)))
1329 bio_put(bio);
1330}
1331
1332/*
1333 * helper to find the stripe number for a given bio. Used to figure out which
1334 * stripe has failed. This expects the bio to correspond to a physical disk,
1335 * so it looks up based on physical sector numbers.
1336 */
1337static int find_bio_stripe(struct btrfs_raid_bio *rbio,
1338 struct bio *bio)
1339{
1340 u64 physical = bio->bi_iter.bi_sector;
1341 int i;
1342 struct btrfs_bio_stripe *stripe;
1343
1344 physical <<= 9;
1345
1346 for (i = 0; i < rbio->bbio->num_stripes; i++) {
1347 stripe = &rbio->bbio->stripes[i];
1348 if (in_range(physical, stripe->physical, rbio->stripe_len) &&
1349 stripe->dev->bdev && bio->bi_bdev == stripe->dev->bdev) {
1350 return i;
1351 }
1352 }
1353 return -1;
1354}
1355
1356/*
1357 * helper to find the stripe number for a given
1358 * bio (before mapping). Used to figure out which stripe has
1359 * failed. This looks up based on logical block numbers.
1360 */
1361static int find_logical_bio_stripe(struct btrfs_raid_bio *rbio,
1362 struct bio *bio)
1363{
1364 u64 logical = bio->bi_iter.bi_sector << 9;
1365 int i;
1366
1367 for (i = 0; i < rbio->nr_data; i++) {
1368 u64 stripe_start = rbio->bbio->raid_map[i];
1369
1370 if (in_range(logical, stripe_start, rbio->stripe_len))
1371 return i;
1372 }
1373 return -1;
1374}
1375
1376/*
1377 * returns -EIO if we had too many failures
1378 */
1379static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed)
1380{
1381 unsigned long flags;
1382 int ret = 0;
1383
1384 spin_lock_irqsave(&rbio->bio_list_lock, flags);
1385
1386 /* we already know this stripe is bad, move on */
1387 if (rbio->faila == failed || rbio->failb == failed)
1388 goto out;
1389
1390 if (rbio->faila == -1) {
1391 /* first failure on this rbio */
1392 rbio->faila = failed;
1393 atomic_inc(&rbio->error);
1394 } else if (rbio->failb == -1) {
1395 /* second failure on this rbio */
1396 rbio->failb = failed;
1397 atomic_inc(&rbio->error);
1398 } else {
1399 ret = -EIO;
1400 }
1401out:
1402 spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
1403
1404 return ret;
1405}
1406
1407/*
1408 * helper to fail a stripe based on a physical disk
1409 * bio.
1410 */
1411static int fail_bio_stripe(struct btrfs_raid_bio *rbio,
1412 struct bio *bio)
1413{
1414 int failed = find_bio_stripe(rbio, bio);
1415
1416 if (failed < 0)
1417 return -EIO;
1418
1419 return fail_rbio_index(rbio, failed);
1420}
1421
1422/*
1423 * this sets each page in the bio uptodate. It should only be used on private
1424 * rbio pages, nothing that comes in from the higher layers
1425 */
1426static void set_bio_pages_uptodate(struct bio *bio)
1427{
1428 struct bio_vec *bvec;
1429 struct bvec_iter_all iter_all;
1430
1431 ASSERT(!bio_flagged(bio, BIO_CLONED));
1432
1433 bio_for_each_segment_all(bvec, bio, iter_all)
1434 SetPageUptodate(bvec->bv_page);
1435}
1436
1437/*
1438 * end io for the read phase of the rmw cycle. All the bios here are physical
1439 * stripe bios we've read from the disk so we can recalculate the parity of the
1440 * stripe.
1441 *
1442 * This will usually kick off finish_rmw once all the bios are read in, but it
1443 * may trigger parity reconstruction if we had any errors along the way
1444 */
1445static void raid_rmw_end_io(struct bio *bio)
1446{
1447 struct btrfs_raid_bio *rbio = bio->bi_private;
1448
1449 if (bio->bi_status)
1450 fail_bio_stripe(rbio, bio);
1451 else
1452 set_bio_pages_uptodate(bio);
1453
1454 bio_put(bio);
1455
1456 if (!atomic_dec_and_test(&rbio->stripes_pending))
1457 return;
1458
1459 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
1460 goto cleanup;
1461
1462 /*
1463 * this will normally call finish_rmw to start our write
1464 * but if there are any failed stripes we'll reconstruct
1465 * from parity first
1466 */
1467 validate_rbio_for_rmw(rbio);
1468 return;
1469
1470cleanup:
1471
1472 rbio_orig_end_io(rbio, BLK_STS_IOERR);
1473}
1474
1475/*
1476 * the stripe must be locked by the caller. It will
1477 * unlock after all the writes are done
1478 */
1479static int raid56_rmw_stripe(struct btrfs_raid_bio *rbio)
1480{
1481 int bios_to_read = 0;
1482 struct bio_list bio_list;
1483 int ret;
1484 int pagenr;
1485 int stripe;
1486 struct bio *bio;
1487
1488 bio_list_init(&bio_list);
1489
1490 ret = alloc_rbio_pages(rbio);
1491 if (ret)
1492 goto cleanup;
1493
1494 index_rbio_pages(rbio);
1495
1496 atomic_set(&rbio->error, 0);
1497 /*
1498 * build a list of bios to read all the missing parts of this
1499 * stripe
1500 */
1501 for (stripe = 0; stripe < rbio->nr_data; stripe++) {
1502 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1503 struct page *page;
1504 /*
1505 * we want to find all the pages missing from
1506 * the rbio and read them from the disk. If
1507 * page_in_rbio finds a page in the bio list
1508 * we don't need to read it off the stripe.
1509 */
1510 page = page_in_rbio(rbio, stripe, pagenr, 1);
1511 if (page)
1512 continue;
1513
1514 page = rbio_stripe_page(rbio, stripe, pagenr);
1515 /*
1516 * the bio cache may have handed us an uptodate
1517 * page. If so, be happy and use it
1518 */
1519 if (PageUptodate(page))
1520 continue;
1521
1522 ret = rbio_add_io_page(rbio, &bio_list, page,
1523 stripe, pagenr, rbio->stripe_len);
1524 if (ret)
1525 goto cleanup;
1526 }
1527 }
1528
1529 bios_to_read = bio_list_size(&bio_list);
1530 if (!bios_to_read) {
1531 /*
1532 * this can happen if others have merged with
1533 * us, it means there is nothing left to read.
1534 * But if there are missing devices it may not be
1535 * safe to do the full stripe write yet.
1536 */
1537 goto finish;
1538 }
1539
1540 /*
1541 * the bbio may be freed once we submit the last bio. Make sure
1542 * not to touch it after that
1543 */
1544 atomic_set(&rbio->stripes_pending, bios_to_read);
1545 while ((bio = bio_list_pop(&bio_list))) {
1546 bio->bi_private = rbio;
1547 bio->bi_end_io = raid_rmw_end_io;
1548 bio->bi_opf = REQ_OP_READ;
1549
1550 btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
1551
1552 submit_bio(bio);
1553 }
1554 /* the actual write will happen once the reads are done */
1555 return 0;
1556
1557cleanup:
1558 rbio_orig_end_io(rbio, BLK_STS_IOERR);
1559
1560 while ((bio = bio_list_pop(&bio_list)))
1561 bio_put(bio);
1562
1563 return -EIO;
1564
1565finish:
1566 validate_rbio_for_rmw(rbio);
1567 return 0;
1568}
1569
1570/*
1571 * if the upper layers pass in a full stripe, we thank them by only allocating
1572 * enough pages to hold the parity, and sending it all down quickly.
1573 */
1574static int full_stripe_write(struct btrfs_raid_bio *rbio)
1575{
1576 int ret;
1577
1578 ret = alloc_rbio_parity_pages(rbio);
1579 if (ret) {
1580 __free_raid_bio(rbio);
1581 return ret;
1582 }
1583
1584 ret = lock_stripe_add(rbio);
1585 if (ret == 0)
1586 finish_rmw(rbio);
1587 return 0;
1588}
1589
1590/*
1591 * partial stripe writes get handed over to async helpers.
1592 * We're really hoping to merge a few more writes into this
1593 * rbio before calculating new parity
1594 */
1595static int partial_stripe_write(struct btrfs_raid_bio *rbio)
1596{
1597 int ret;
1598
1599 ret = lock_stripe_add(rbio);
1600 if (ret == 0)
1601 start_async_work(rbio, rmw_work);
1602 return 0;
1603}
1604
1605/*
1606 * sometimes while we were reading from the drive to
1607 * recalculate parity, enough new bios come into create
1608 * a full stripe. So we do a check here to see if we can
1609 * go directly to finish_rmw
1610 */
1611static int __raid56_parity_write(struct btrfs_raid_bio *rbio)
1612{
1613 /* head off into rmw land if we don't have a full stripe */
1614 if (!rbio_is_full(rbio))
1615 return partial_stripe_write(rbio);
1616 return full_stripe_write(rbio);
1617}
1618
1619/*
1620 * We use plugging call backs to collect full stripes.
1621 * Any time we get a partial stripe write while plugged
1622 * we collect it into a list. When the unplug comes down,
1623 * we sort the list by logical block number and merge
1624 * everything we can into the same rbios
1625 */
1626struct btrfs_plug_cb {
1627 struct blk_plug_cb cb;
1628 struct btrfs_fs_info *info;
1629 struct list_head rbio_list;
1630 struct btrfs_work work;
1631};
1632
1633/*
1634 * rbios on the plug list are sorted for easier merging.
1635 */
1636static int plug_cmp(void *priv, const struct list_head *a,
1637 const struct list_head *b)
1638{
1639 struct btrfs_raid_bio *ra = container_of(a, struct btrfs_raid_bio,
1640 plug_list);
1641 struct btrfs_raid_bio *rb = container_of(b, struct btrfs_raid_bio,
1642 plug_list);
1643 u64 a_sector = ra->bio_list.head->bi_iter.bi_sector;
1644 u64 b_sector = rb->bio_list.head->bi_iter.bi_sector;
1645
1646 if (a_sector < b_sector)
1647 return -1;
1648 if (a_sector > b_sector)
1649 return 1;
1650 return 0;
1651}
1652
1653static void run_plug(struct btrfs_plug_cb *plug)
1654{
1655 struct btrfs_raid_bio *cur;
1656 struct btrfs_raid_bio *last = NULL;
1657
1658 /*
1659 * sort our plug list then try to merge
1660 * everything we can in hopes of creating full
1661 * stripes.
1662 */
1663 list_sort(NULL, &plug->rbio_list, plug_cmp);
1664 while (!list_empty(&plug->rbio_list)) {
1665 cur = list_entry(plug->rbio_list.next,
1666 struct btrfs_raid_bio, plug_list);
1667 list_del_init(&cur->plug_list);
1668
1669 if (rbio_is_full(cur)) {
1670 int ret;
1671
1672 /* we have a full stripe, send it down */
1673 ret = full_stripe_write(cur);
1674 BUG_ON(ret);
1675 continue;
1676 }
1677 if (last) {
1678 if (rbio_can_merge(last, cur)) {
1679 merge_rbio(last, cur);
1680 __free_raid_bio(cur);
1681 continue;
1682
1683 }
1684 __raid56_parity_write(last);
1685 }
1686 last = cur;
1687 }
1688 if (last) {
1689 __raid56_parity_write(last);
1690 }
1691 kfree(plug);
1692}
1693
1694/*
1695 * if the unplug comes from schedule, we have to push the
1696 * work off to a helper thread
1697 */
1698static void unplug_work(struct btrfs_work *work)
1699{
1700 struct btrfs_plug_cb *plug;
1701 plug = container_of(work, struct btrfs_plug_cb, work);
1702 run_plug(plug);
1703}
1704
1705static void btrfs_raid_unplug(struct blk_plug_cb *cb, bool from_schedule)
1706{
1707 struct btrfs_plug_cb *plug;
1708 plug = container_of(cb, struct btrfs_plug_cb, cb);
1709
1710 if (from_schedule) {
1711 btrfs_init_work(&plug->work, unplug_work, NULL, NULL);
1712 btrfs_queue_work(plug->info->rmw_workers,
1713 &plug->work);
1714 return;
1715 }
1716 run_plug(plug);
1717}
1718
1719/*
1720 * our main entry point for writes from the rest of the FS.
1721 */
1722int raid56_parity_write(struct btrfs_fs_info *fs_info, struct bio *bio,
1723 struct btrfs_bio *bbio, u64 stripe_len)
1724{
1725 struct btrfs_raid_bio *rbio;
1726 struct btrfs_plug_cb *plug = NULL;
1727 struct blk_plug_cb *cb;
1728 int ret;
1729
1730 rbio = alloc_rbio(fs_info, bbio, stripe_len);
1731 if (IS_ERR(rbio)) {
1732 btrfs_put_bbio(bbio);
1733 return PTR_ERR(rbio);
1734 }
1735 bio_list_add(&rbio->bio_list, bio);
1736 rbio->bio_list_bytes = bio->bi_iter.bi_size;
1737 rbio->operation = BTRFS_RBIO_WRITE;
1738
1739 btrfs_bio_counter_inc_noblocked(fs_info);
1740 rbio->generic_bio_cnt = 1;
1741
1742 /*
1743 * don't plug on full rbios, just get them out the door
1744 * as quickly as we can
1745 */
1746 if (rbio_is_full(rbio)) {
1747 ret = full_stripe_write(rbio);
1748 if (ret)
1749 btrfs_bio_counter_dec(fs_info);
1750 return ret;
1751 }
1752
1753 cb = blk_check_plugged(btrfs_raid_unplug, fs_info, sizeof(*plug));
1754 if (cb) {
1755 plug = container_of(cb, struct btrfs_plug_cb, cb);
1756 if (!plug->info) {
1757 plug->info = fs_info;
1758 INIT_LIST_HEAD(&plug->rbio_list);
1759 }
1760 list_add_tail(&rbio->plug_list, &plug->rbio_list);
1761 ret = 0;
1762 } else {
1763 ret = __raid56_parity_write(rbio);
1764 if (ret)
1765 btrfs_bio_counter_dec(fs_info);
1766 }
1767 return ret;
1768}
1769
1770/*
1771 * all parity reconstruction happens here. We've read in everything
1772 * we can find from the drives and this does the heavy lifting of
1773 * sorting the good from the bad.
1774 */
1775static void __raid_recover_end_io(struct btrfs_raid_bio *rbio)
1776{
1777 int pagenr, stripe;
1778 void **pointers;
1779 void **unmap_array;
1780 int faila = -1, failb = -1;
1781 struct page *page;
1782 blk_status_t err;
1783 int i;
1784
1785 pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
1786 if (!pointers) {
1787 err = BLK_STS_RESOURCE;
1788 goto cleanup_io;
1789 }
1790
1791 /*
1792 * Store copy of pointers that does not get reordered during
1793 * reconstruction so that kunmap_local works.
1794 */
1795 unmap_array = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
1796 if (!unmap_array) {
1797 err = BLK_STS_RESOURCE;
1798 goto cleanup_pointers;
1799 }
1800
1801 faila = rbio->faila;
1802 failb = rbio->failb;
1803
1804 if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1805 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) {
1806 spin_lock_irq(&rbio->bio_list_lock);
1807 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1808 spin_unlock_irq(&rbio->bio_list_lock);
1809 }
1810
1811 index_rbio_pages(rbio);
1812
1813 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
1814 /*
1815 * Now we just use bitmap to mark the horizontal stripes in
1816 * which we have data when doing parity scrub.
1817 */
1818 if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB &&
1819 !test_bit(pagenr, rbio->dbitmap))
1820 continue;
1821
1822 /*
1823 * Setup our array of pointers with pages from each stripe
1824 *
1825 * NOTE: store a duplicate array of pointers to preserve the
1826 * pointer order
1827 */
1828 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1829 /*
1830 * if we're rebuilding a read, we have to use
1831 * pages from the bio list
1832 */
1833 if ((rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1834 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) &&
1835 (stripe == faila || stripe == failb)) {
1836 page = page_in_rbio(rbio, stripe, pagenr, 0);
1837 } else {
1838 page = rbio_stripe_page(rbio, stripe, pagenr);
1839 }
1840 pointers[stripe] = kmap_local_page(page);
1841 unmap_array[stripe] = pointers[stripe];
1842 }
1843
1844 /* all raid6 handling here */
1845 if (rbio->bbio->map_type & BTRFS_BLOCK_GROUP_RAID6) {
1846 /*
1847 * single failure, rebuild from parity raid5
1848 * style
1849 */
1850 if (failb < 0) {
1851 if (faila == rbio->nr_data) {
1852 /*
1853 * Just the P stripe has failed, without
1854 * a bad data or Q stripe.
1855 * TODO, we should redo the xor here.
1856 */
1857 err = BLK_STS_IOERR;
1858 goto cleanup;
1859 }
1860 /*
1861 * a single failure in raid6 is rebuilt
1862 * in the pstripe code below
1863 */
1864 goto pstripe;
1865 }
1866
1867 /* make sure our ps and qs are in order */
1868 if (faila > failb)
1869 swap(faila, failb);
1870
1871 /* if the q stripe is failed, do a pstripe reconstruction
1872 * from the xors.
1873 * If both the q stripe and the P stripe are failed, we're
1874 * here due to a crc mismatch and we can't give them the
1875 * data they want
1876 */
1877 if (rbio->bbio->raid_map[failb] == RAID6_Q_STRIPE) {
1878 if (rbio->bbio->raid_map[faila] ==
1879 RAID5_P_STRIPE) {
1880 err = BLK_STS_IOERR;
1881 goto cleanup;
1882 }
1883 /*
1884 * otherwise we have one bad data stripe and
1885 * a good P stripe. raid5!
1886 */
1887 goto pstripe;
1888 }
1889
1890 if (rbio->bbio->raid_map[failb] == RAID5_P_STRIPE) {
1891 raid6_datap_recov(rbio->real_stripes,
1892 PAGE_SIZE, faila, pointers);
1893 } else {
1894 raid6_2data_recov(rbio->real_stripes,
1895 PAGE_SIZE, faila, failb,
1896 pointers);
1897 }
1898 } else {
1899 void *p;
1900
1901 /* rebuild from P stripe here (raid5 or raid6) */
1902 BUG_ON(failb != -1);
1903pstripe:
1904 /* Copy parity block into failed block to start with */
1905 copy_page(pointers[faila], pointers[rbio->nr_data]);
1906
1907 /* rearrange the pointer array */
1908 p = pointers[faila];
1909 for (stripe = faila; stripe < rbio->nr_data - 1; stripe++)
1910 pointers[stripe] = pointers[stripe + 1];
1911 pointers[rbio->nr_data - 1] = p;
1912
1913 /* xor in the rest */
1914 run_xor(pointers, rbio->nr_data - 1, PAGE_SIZE);
1915 }
1916 /* if we're doing this rebuild as part of an rmw, go through
1917 * and set all of our private rbio pages in the
1918 * failed stripes as uptodate. This way finish_rmw will
1919 * know they can be trusted. If this was a read reconstruction,
1920 * other endio functions will fiddle the uptodate bits
1921 */
1922 if (rbio->operation == BTRFS_RBIO_WRITE) {
1923 for (i = 0; i < rbio->stripe_npages; i++) {
1924 if (faila != -1) {
1925 page = rbio_stripe_page(rbio, faila, i);
1926 SetPageUptodate(page);
1927 }
1928 if (failb != -1) {
1929 page = rbio_stripe_page(rbio, failb, i);
1930 SetPageUptodate(page);
1931 }
1932 }
1933 }
1934 for (stripe = rbio->real_stripes - 1; stripe >= 0; stripe--)
1935 kunmap_local(unmap_array[stripe]);
1936 }
1937
1938 err = BLK_STS_OK;
1939cleanup:
1940 kfree(unmap_array);
1941cleanup_pointers:
1942 kfree(pointers);
1943
1944cleanup_io:
1945 /*
1946 * Similar to READ_REBUILD, REBUILD_MISSING at this point also has a
1947 * valid rbio which is consistent with ondisk content, thus such a
1948 * valid rbio can be cached to avoid further disk reads.
1949 */
1950 if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
1951 rbio->operation == BTRFS_RBIO_REBUILD_MISSING) {
1952 /*
1953 * - In case of two failures, where rbio->failb != -1:
1954 *
1955 * Do not cache this rbio since the above read reconstruction
1956 * (raid6_datap_recov() or raid6_2data_recov()) may have
1957 * changed some content of stripes which are not identical to
1958 * on-disk content any more, otherwise, a later write/recover
1959 * may steal stripe_pages from this rbio and end up with
1960 * corruptions or rebuild failures.
1961 *
1962 * - In case of single failure, where rbio->failb == -1:
1963 *
1964 * Cache this rbio iff the above read reconstruction is
1965 * executed without problems.
1966 */
1967 if (err == BLK_STS_OK && rbio->failb < 0)
1968 cache_rbio_pages(rbio);
1969 else
1970 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
1971
1972 rbio_orig_end_io(rbio, err);
1973 } else if (err == BLK_STS_OK) {
1974 rbio->faila = -1;
1975 rbio->failb = -1;
1976
1977 if (rbio->operation == BTRFS_RBIO_WRITE)
1978 finish_rmw(rbio);
1979 else if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB)
1980 finish_parity_scrub(rbio, 0);
1981 else
1982 BUG();
1983 } else {
1984 rbio_orig_end_io(rbio, err);
1985 }
1986}
1987
1988/*
1989 * This is called only for stripes we've read from disk to
1990 * reconstruct the parity.
1991 */
1992static void raid_recover_end_io(struct bio *bio)
1993{
1994 struct btrfs_raid_bio *rbio = bio->bi_private;
1995
1996 /*
1997 * we only read stripe pages off the disk, set them
1998 * up to date if there were no errors
1999 */
2000 if (bio->bi_status)
2001 fail_bio_stripe(rbio, bio);
2002 else
2003 set_bio_pages_uptodate(bio);
2004 bio_put(bio);
2005
2006 if (!atomic_dec_and_test(&rbio->stripes_pending))
2007 return;
2008
2009 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
2010 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2011 else
2012 __raid_recover_end_io(rbio);
2013}
2014
2015/*
2016 * reads everything we need off the disk to reconstruct
2017 * the parity. endio handlers trigger final reconstruction
2018 * when the IO is done.
2019 *
2020 * This is used both for reads from the higher layers and for
2021 * parity construction required to finish a rmw cycle.
2022 */
2023static int __raid56_parity_recover(struct btrfs_raid_bio *rbio)
2024{
2025 int bios_to_read = 0;
2026 struct bio_list bio_list;
2027 int ret;
2028 int pagenr;
2029 int stripe;
2030 struct bio *bio;
2031
2032 bio_list_init(&bio_list);
2033
2034 ret = alloc_rbio_pages(rbio);
2035 if (ret)
2036 goto cleanup;
2037
2038 atomic_set(&rbio->error, 0);
2039
2040 /*
2041 * read everything that hasn't failed. Thanks to the
2042 * stripe cache, it is possible that some or all of these
2043 * pages are going to be uptodate.
2044 */
2045 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
2046 if (rbio->faila == stripe || rbio->failb == stripe) {
2047 atomic_inc(&rbio->error);
2048 continue;
2049 }
2050
2051 for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
2052 struct page *p;
2053
2054 /*
2055 * the rmw code may have already read this
2056 * page in
2057 */
2058 p = rbio_stripe_page(rbio, stripe, pagenr);
2059 if (PageUptodate(p))
2060 continue;
2061
2062 ret = rbio_add_io_page(rbio, &bio_list,
2063 rbio_stripe_page(rbio, stripe, pagenr),
2064 stripe, pagenr, rbio->stripe_len);
2065 if (ret < 0)
2066 goto cleanup;
2067 }
2068 }
2069
2070 bios_to_read = bio_list_size(&bio_list);
2071 if (!bios_to_read) {
2072 /*
2073 * we might have no bios to read just because the pages
2074 * were up to date, or we might have no bios to read because
2075 * the devices were gone.
2076 */
2077 if (atomic_read(&rbio->error) <= rbio->bbio->max_errors) {
2078 __raid_recover_end_io(rbio);
2079 return 0;
2080 } else {
2081 goto cleanup;
2082 }
2083 }
2084
2085 /*
2086 * the bbio may be freed once we submit the last bio. Make sure
2087 * not to touch it after that
2088 */
2089 atomic_set(&rbio->stripes_pending, bios_to_read);
2090 while ((bio = bio_list_pop(&bio_list))) {
2091 bio->bi_private = rbio;
2092 bio->bi_end_io = raid_recover_end_io;
2093 bio->bi_opf = REQ_OP_READ;
2094
2095 btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
2096
2097 submit_bio(bio);
2098 }
2099
2100 return 0;
2101
2102cleanup:
2103 if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
2104 rbio->operation == BTRFS_RBIO_REBUILD_MISSING)
2105 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2106
2107 while ((bio = bio_list_pop(&bio_list)))
2108 bio_put(bio);
2109
2110 return -EIO;
2111}
2112
2113/*
2114 * the main entry point for reads from the higher layers. This
2115 * is really only called when the normal read path had a failure,
2116 * so we assume the bio they send down corresponds to a failed part
2117 * of the drive.
2118 */
2119int raid56_parity_recover(struct btrfs_fs_info *fs_info, struct bio *bio,
2120 struct btrfs_bio *bbio, u64 stripe_len,
2121 int mirror_num, int generic_io)
2122{
2123 struct btrfs_raid_bio *rbio;
2124 int ret;
2125
2126 if (generic_io) {
2127 ASSERT(bbio->mirror_num == mirror_num);
2128 btrfs_io_bio(bio)->mirror_num = mirror_num;
2129 }
2130
2131 rbio = alloc_rbio(fs_info, bbio, stripe_len);
2132 if (IS_ERR(rbio)) {
2133 if (generic_io)
2134 btrfs_put_bbio(bbio);
2135 return PTR_ERR(rbio);
2136 }
2137
2138 rbio->operation = BTRFS_RBIO_READ_REBUILD;
2139 bio_list_add(&rbio->bio_list, bio);
2140 rbio->bio_list_bytes = bio->bi_iter.bi_size;
2141
2142 rbio->faila = find_logical_bio_stripe(rbio, bio);
2143 if (rbio->faila == -1) {
2144 btrfs_warn(fs_info,
2145 "%s could not find the bad stripe in raid56 so that we cannot recover any more (bio has logical %llu len %llu, bbio has map_type %llu)",
2146 __func__, bio->bi_iter.bi_sector << 9,
2147 (u64)bio->bi_iter.bi_size, bbio->map_type);
2148 if (generic_io)
2149 btrfs_put_bbio(bbio);
2150 kfree(rbio);
2151 return -EIO;
2152 }
2153
2154 if (generic_io) {
2155 btrfs_bio_counter_inc_noblocked(fs_info);
2156 rbio->generic_bio_cnt = 1;
2157 } else {
2158 btrfs_get_bbio(bbio);
2159 }
2160
2161 /*
2162 * Loop retry:
2163 * for 'mirror == 2', reconstruct from all other stripes.
2164 * for 'mirror_num > 2', select a stripe to fail on every retry.
2165 */
2166 if (mirror_num > 2) {
2167 /*
2168 * 'mirror == 3' is to fail the p stripe and
2169 * reconstruct from the q stripe. 'mirror > 3' is to
2170 * fail a data stripe and reconstruct from p+q stripe.
2171 */
2172 rbio->failb = rbio->real_stripes - (mirror_num - 1);
2173 ASSERT(rbio->failb > 0);
2174 if (rbio->failb <= rbio->faila)
2175 rbio->failb--;
2176 }
2177
2178 ret = lock_stripe_add(rbio);
2179
2180 /*
2181 * __raid56_parity_recover will end the bio with
2182 * any errors it hits. We don't want to return
2183 * its error value up the stack because our caller
2184 * will end up calling bio_endio with any nonzero
2185 * return
2186 */
2187 if (ret == 0)
2188 __raid56_parity_recover(rbio);
2189 /*
2190 * our rbio has been added to the list of
2191 * rbios that will be handled after the
2192 * currently lock owner is done
2193 */
2194 return 0;
2195
2196}
2197
2198static void rmw_work(struct btrfs_work *work)
2199{
2200 struct btrfs_raid_bio *rbio;
2201
2202 rbio = container_of(work, struct btrfs_raid_bio, work);
2203 raid56_rmw_stripe(rbio);
2204}
2205
2206static void read_rebuild_work(struct btrfs_work *work)
2207{
2208 struct btrfs_raid_bio *rbio;
2209
2210 rbio = container_of(work, struct btrfs_raid_bio, work);
2211 __raid56_parity_recover(rbio);
2212}
2213
2214/*
2215 * The following code is used to scrub/replace the parity stripe
2216 *
2217 * Caller must have already increased bio_counter for getting @bbio.
2218 *
2219 * Note: We need make sure all the pages that add into the scrub/replace
2220 * raid bio are correct and not be changed during the scrub/replace. That
2221 * is those pages just hold metadata or file data with checksum.
2222 */
2223
2224struct btrfs_raid_bio *
2225raid56_parity_alloc_scrub_rbio(struct btrfs_fs_info *fs_info, struct bio *bio,
2226 struct btrfs_bio *bbio, u64 stripe_len,
2227 struct btrfs_device *scrub_dev,
2228 unsigned long *dbitmap, int stripe_nsectors)
2229{
2230 struct btrfs_raid_bio *rbio;
2231 int i;
2232
2233 rbio = alloc_rbio(fs_info, bbio, stripe_len);
2234 if (IS_ERR(rbio))
2235 return NULL;
2236 bio_list_add(&rbio->bio_list, bio);
2237 /*
2238 * This is a special bio which is used to hold the completion handler
2239 * and make the scrub rbio is similar to the other types
2240 */
2241 ASSERT(!bio->bi_iter.bi_size);
2242 rbio->operation = BTRFS_RBIO_PARITY_SCRUB;
2243
2244 /*
2245 * After mapping bbio with BTRFS_MAP_WRITE, parities have been sorted
2246 * to the end position, so this search can start from the first parity
2247 * stripe.
2248 */
2249 for (i = rbio->nr_data; i < rbio->real_stripes; i++) {
2250 if (bbio->stripes[i].dev == scrub_dev) {
2251 rbio->scrubp = i;
2252 break;
2253 }
2254 }
2255 ASSERT(i < rbio->real_stripes);
2256
2257 /* Now we just support the sectorsize equals to page size */
2258 ASSERT(fs_info->sectorsize == PAGE_SIZE);
2259 ASSERT(rbio->stripe_npages == stripe_nsectors);
2260 bitmap_copy(rbio->dbitmap, dbitmap, stripe_nsectors);
2261
2262 /*
2263 * We have already increased bio_counter when getting bbio, record it
2264 * so we can free it at rbio_orig_end_io().
2265 */
2266 rbio->generic_bio_cnt = 1;
2267
2268 return rbio;
2269}
2270
2271/* Used for both parity scrub and missing. */
2272void raid56_add_scrub_pages(struct btrfs_raid_bio *rbio, struct page *page,
2273 u64 logical)
2274{
2275 int stripe_offset;
2276 int index;
2277
2278 ASSERT(logical >= rbio->bbio->raid_map[0]);
2279 ASSERT(logical + PAGE_SIZE <= rbio->bbio->raid_map[0] +
2280 rbio->stripe_len * rbio->nr_data);
2281 stripe_offset = (int)(logical - rbio->bbio->raid_map[0]);
2282 index = stripe_offset >> PAGE_SHIFT;
2283 rbio->bio_pages[index] = page;
2284}
2285
2286/*
2287 * We just scrub the parity that we have correct data on the same horizontal,
2288 * so we needn't allocate all pages for all the stripes.
2289 */
2290static int alloc_rbio_essential_pages(struct btrfs_raid_bio *rbio)
2291{
2292 int i;
2293 int bit;
2294 int index;
2295 struct page *page;
2296
2297 for_each_set_bit(bit, rbio->dbitmap, rbio->stripe_npages) {
2298 for (i = 0; i < rbio->real_stripes; i++) {
2299 index = i * rbio->stripe_npages + bit;
2300 if (rbio->stripe_pages[index])
2301 continue;
2302
2303 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2304 if (!page)
2305 return -ENOMEM;
2306 rbio->stripe_pages[index] = page;
2307 }
2308 }
2309 return 0;
2310}
2311
2312static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
2313 int need_check)
2314{
2315 struct btrfs_bio *bbio = rbio->bbio;
2316 void **pointers = rbio->finish_pointers;
2317 unsigned long *pbitmap = rbio->finish_pbitmap;
2318 int nr_data = rbio->nr_data;
2319 int stripe;
2320 int pagenr;
2321 bool has_qstripe;
2322 struct page *p_page = NULL;
2323 struct page *q_page = NULL;
2324 struct bio_list bio_list;
2325 struct bio *bio;
2326 int is_replace = 0;
2327 int ret;
2328
2329 bio_list_init(&bio_list);
2330
2331 if (rbio->real_stripes - rbio->nr_data == 1)
2332 has_qstripe = false;
2333 else if (rbio->real_stripes - rbio->nr_data == 2)
2334 has_qstripe = true;
2335 else
2336 BUG();
2337
2338 if (bbio->num_tgtdevs && bbio->tgtdev_map[rbio->scrubp]) {
2339 is_replace = 1;
2340 bitmap_copy(pbitmap, rbio->dbitmap, rbio->stripe_npages);
2341 }
2342
2343 /*
2344 * Because the higher layers(scrubber) are unlikely to
2345 * use this area of the disk again soon, so don't cache
2346 * it.
2347 */
2348 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
2349
2350 if (!need_check)
2351 goto writeback;
2352
2353 p_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2354 if (!p_page)
2355 goto cleanup;
2356 SetPageUptodate(p_page);
2357
2358 if (has_qstripe) {
2359 /* RAID6, allocate and map temp space for the Q stripe */
2360 q_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2361 if (!q_page) {
2362 __free_page(p_page);
2363 goto cleanup;
2364 }
2365 SetPageUptodate(q_page);
2366 pointers[rbio->real_stripes - 1] = kmap_local_page(q_page);
2367 }
2368
2369 atomic_set(&rbio->error, 0);
2370
2371 /* Map the parity stripe just once */
2372 pointers[nr_data] = kmap_local_page(p_page);
2373
2374 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2375 struct page *p;
2376 void *parity;
2377 /* first collect one page from each data stripe */
2378 for (stripe = 0; stripe < nr_data; stripe++) {
2379 p = page_in_rbio(rbio, stripe, pagenr, 0);
2380 pointers[stripe] = kmap_local_page(p);
2381 }
2382
2383 if (has_qstripe) {
2384 /* RAID6, call the library function to fill in our P/Q */
2385 raid6_call.gen_syndrome(rbio->real_stripes, PAGE_SIZE,
2386 pointers);
2387 } else {
2388 /* raid5 */
2389 copy_page(pointers[nr_data], pointers[0]);
2390 run_xor(pointers + 1, nr_data - 1, PAGE_SIZE);
2391 }
2392
2393 /* Check scrubbing parity and repair it */
2394 p = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2395 parity = kmap_local_page(p);
2396 if (memcmp(parity, pointers[rbio->scrubp], PAGE_SIZE))
2397 copy_page(parity, pointers[rbio->scrubp]);
2398 else
2399 /* Parity is right, needn't writeback */
2400 bitmap_clear(rbio->dbitmap, pagenr, 1);
2401 kunmap_local(parity);
2402
2403 for (stripe = nr_data - 1; stripe >= 0; stripe--)
2404 kunmap_local(pointers[stripe]);
2405 }
2406
2407 kunmap_local(pointers[nr_data]);
2408 __free_page(p_page);
2409 if (q_page) {
2410 kunmap_local(pointers[rbio->real_stripes - 1]);
2411 __free_page(q_page);
2412 }
2413
2414writeback:
2415 /*
2416 * time to start writing. Make bios for everything from the
2417 * higher layers (the bio_list in our rbio) and our p/q. Ignore
2418 * everything else.
2419 */
2420 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2421 struct page *page;
2422
2423 page = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2424 ret = rbio_add_io_page(rbio, &bio_list,
2425 page, rbio->scrubp, pagenr, rbio->stripe_len);
2426 if (ret)
2427 goto cleanup;
2428 }
2429
2430 if (!is_replace)
2431 goto submit_write;
2432
2433 for_each_set_bit(pagenr, pbitmap, rbio->stripe_npages) {
2434 struct page *page;
2435
2436 page = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2437 ret = rbio_add_io_page(rbio, &bio_list, page,
2438 bbio->tgtdev_map[rbio->scrubp],
2439 pagenr, rbio->stripe_len);
2440 if (ret)
2441 goto cleanup;
2442 }
2443
2444submit_write:
2445 nr_data = bio_list_size(&bio_list);
2446 if (!nr_data) {
2447 /* Every parity is right */
2448 rbio_orig_end_io(rbio, BLK_STS_OK);
2449 return;
2450 }
2451
2452 atomic_set(&rbio->stripes_pending, nr_data);
2453
2454 while ((bio = bio_list_pop(&bio_list))) {
2455 bio->bi_private = rbio;
2456 bio->bi_end_io = raid_write_end_io;
2457 bio->bi_opf = REQ_OP_WRITE;
2458
2459 submit_bio(bio);
2460 }
2461 return;
2462
2463cleanup:
2464 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2465
2466 while ((bio = bio_list_pop(&bio_list)))
2467 bio_put(bio);
2468}
2469
2470static inline int is_data_stripe(struct btrfs_raid_bio *rbio, int stripe)
2471{
2472 if (stripe >= 0 && stripe < rbio->nr_data)
2473 return 1;
2474 return 0;
2475}
2476
2477/*
2478 * While we're doing the parity check and repair, we could have errors
2479 * in reading pages off the disk. This checks for errors and if we're
2480 * not able to read the page it'll trigger parity reconstruction. The
2481 * parity scrub will be finished after we've reconstructed the failed
2482 * stripes
2483 */
2484static void validate_rbio_for_parity_scrub(struct btrfs_raid_bio *rbio)
2485{
2486 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
2487 goto cleanup;
2488
2489 if (rbio->faila >= 0 || rbio->failb >= 0) {
2490 int dfail = 0, failp = -1;
2491
2492 if (is_data_stripe(rbio, rbio->faila))
2493 dfail++;
2494 else if (is_parity_stripe(rbio->faila))
2495 failp = rbio->faila;
2496
2497 if (is_data_stripe(rbio, rbio->failb))
2498 dfail++;
2499 else if (is_parity_stripe(rbio->failb))
2500 failp = rbio->failb;
2501
2502 /*
2503 * Because we can not use a scrubbing parity to repair
2504 * the data, so the capability of the repair is declined.
2505 * (In the case of RAID5, we can not repair anything)
2506 */
2507 if (dfail > rbio->bbio->max_errors - 1)
2508 goto cleanup;
2509
2510 /*
2511 * If all data is good, only parity is correctly, just
2512 * repair the parity.
2513 */
2514 if (dfail == 0) {
2515 finish_parity_scrub(rbio, 0);
2516 return;
2517 }
2518
2519 /*
2520 * Here means we got one corrupted data stripe and one
2521 * corrupted parity on RAID6, if the corrupted parity
2522 * is scrubbing parity, luckily, use the other one to repair
2523 * the data, or we can not repair the data stripe.
2524 */
2525 if (failp != rbio->scrubp)
2526 goto cleanup;
2527
2528 __raid_recover_end_io(rbio);
2529 } else {
2530 finish_parity_scrub(rbio, 1);
2531 }
2532 return;
2533
2534cleanup:
2535 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2536}
2537
2538/*
2539 * end io for the read phase of the rmw cycle. All the bios here are physical
2540 * stripe bios we've read from the disk so we can recalculate the parity of the
2541 * stripe.
2542 *
2543 * This will usually kick off finish_rmw once all the bios are read in, but it
2544 * may trigger parity reconstruction if we had any errors along the way
2545 */
2546static void raid56_parity_scrub_end_io(struct bio *bio)
2547{
2548 struct btrfs_raid_bio *rbio = bio->bi_private;
2549
2550 if (bio->bi_status)
2551 fail_bio_stripe(rbio, bio);
2552 else
2553 set_bio_pages_uptodate(bio);
2554
2555 bio_put(bio);
2556
2557 if (!atomic_dec_and_test(&rbio->stripes_pending))
2558 return;
2559
2560 /*
2561 * this will normally call finish_rmw to start our write
2562 * but if there are any failed stripes we'll reconstruct
2563 * from parity first
2564 */
2565 validate_rbio_for_parity_scrub(rbio);
2566}
2567
2568static void raid56_parity_scrub_stripe(struct btrfs_raid_bio *rbio)
2569{
2570 int bios_to_read = 0;
2571 struct bio_list bio_list;
2572 int ret;
2573 int pagenr;
2574 int stripe;
2575 struct bio *bio;
2576
2577 bio_list_init(&bio_list);
2578
2579 ret = alloc_rbio_essential_pages(rbio);
2580 if (ret)
2581 goto cleanup;
2582
2583 atomic_set(&rbio->error, 0);
2584 /*
2585 * build a list of bios to read all the missing parts of this
2586 * stripe
2587 */
2588 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
2589 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2590 struct page *page;
2591 /*
2592 * we want to find all the pages missing from
2593 * the rbio and read them from the disk. If
2594 * page_in_rbio finds a page in the bio list
2595 * we don't need to read it off the stripe.
2596 */
2597 page = page_in_rbio(rbio, stripe, pagenr, 1);
2598 if (page)
2599 continue;
2600
2601 page = rbio_stripe_page(rbio, stripe, pagenr);
2602 /*
2603 * the bio cache may have handed us an uptodate
2604 * page. If so, be happy and use it
2605 */
2606 if (PageUptodate(page))
2607 continue;
2608
2609 ret = rbio_add_io_page(rbio, &bio_list, page,
2610 stripe, pagenr, rbio->stripe_len);
2611 if (ret)
2612 goto cleanup;
2613 }
2614 }
2615
2616 bios_to_read = bio_list_size(&bio_list);
2617 if (!bios_to_read) {
2618 /*
2619 * this can happen if others have merged with
2620 * us, it means there is nothing left to read.
2621 * But if there are missing devices it may not be
2622 * safe to do the full stripe write yet.
2623 */
2624 goto finish;
2625 }
2626
2627 /*
2628 * the bbio may be freed once we submit the last bio. Make sure
2629 * not to touch it after that
2630 */
2631 atomic_set(&rbio->stripes_pending, bios_to_read);
2632 while ((bio = bio_list_pop(&bio_list))) {
2633 bio->bi_private = rbio;
2634 bio->bi_end_io = raid56_parity_scrub_end_io;
2635 bio->bi_opf = REQ_OP_READ;
2636
2637 btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
2638
2639 submit_bio(bio);
2640 }
2641 /* the actual write will happen once the reads are done */
2642 return;
2643
2644cleanup:
2645 rbio_orig_end_io(rbio, BLK_STS_IOERR);
2646
2647 while ((bio = bio_list_pop(&bio_list)))
2648 bio_put(bio);
2649
2650 return;
2651
2652finish:
2653 validate_rbio_for_parity_scrub(rbio);
2654}
2655
2656static void scrub_parity_work(struct btrfs_work *work)
2657{
2658 struct btrfs_raid_bio *rbio;
2659
2660 rbio = container_of(work, struct btrfs_raid_bio, work);
2661 raid56_parity_scrub_stripe(rbio);
2662}
2663
2664void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio)
2665{
2666 if (!lock_stripe_add(rbio))
2667 start_async_work(rbio, scrub_parity_work);
2668}
2669
2670/* The following code is used for dev replace of a missing RAID 5/6 device. */
2671
2672struct btrfs_raid_bio *
2673raid56_alloc_missing_rbio(struct btrfs_fs_info *fs_info, struct bio *bio,
2674 struct btrfs_bio *bbio, u64 length)
2675{
2676 struct btrfs_raid_bio *rbio;
2677
2678 rbio = alloc_rbio(fs_info, bbio, length);
2679 if (IS_ERR(rbio))
2680 return NULL;
2681
2682 rbio->operation = BTRFS_RBIO_REBUILD_MISSING;
2683 bio_list_add(&rbio->bio_list, bio);
2684 /*
2685 * This is a special bio which is used to hold the completion handler
2686 * and make the scrub rbio is similar to the other types
2687 */
2688 ASSERT(!bio->bi_iter.bi_size);
2689
2690 rbio->faila = find_logical_bio_stripe(rbio, bio);
2691 if (rbio->faila == -1) {
2692 BUG();
2693 kfree(rbio);
2694 return NULL;
2695 }
2696
2697 /*
2698 * When we get bbio, we have already increased bio_counter, record it
2699 * so we can free it at rbio_orig_end_io()
2700 */
2701 rbio->generic_bio_cnt = 1;
2702
2703 return rbio;
2704}
2705
2706void raid56_submit_missing_rbio(struct btrfs_raid_bio *rbio)
2707{
2708 if (!lock_stripe_add(rbio))
2709 start_async_work(rbio, read_rebuild_work);
2710}