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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/*
2 * Copyright (C) 2012 Fusion-io All rights reserved.
3 * Copyright (C) 2012 Intel Corp. All rights reserved.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public
7 * License v2 as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public
15 * License along with this program; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 021110-1307, USA.
18 */
19#include <linux/sched.h>
20#include <linux/wait.h>
21#include <linux/bio.h>
22#include <linux/slab.h>
23#include <linux/buffer_head.h>
24#include <linux/blkdev.h>
25#include <linux/random.h>
26#include <linux/iocontext.h>
27#include <linux/capability.h>
28#include <linux/ratelimit.h>
29#include <linux/kthread.h>
30#include <linux/raid/pq.h>
31#include <linux/hash.h>
32#include <linux/list_sort.h>
33#include <linux/raid/xor.h>
34#include <linux/vmalloc.h>
35#include <asm/div64.h>
36#include "ctree.h"
37#include "extent_map.h"
38#include "disk-io.h"
39#include "transaction.h"
40#include "print-tree.h"
41#include "volumes.h"
42#include "raid56.h"
43#include "async-thread.h"
44#include "check-integrity.h"
45#include "rcu-string.h"
46
47/* set when additional merges to this rbio are not allowed */
48#define RBIO_RMW_LOCKED_BIT 1
49
50/*
51 * set when this rbio is sitting in the hash, but it is just a cache
52 * of past RMW
53 */
54#define RBIO_CACHE_BIT 2
55
56/*
57 * set when it is safe to trust the stripe_pages for caching
58 */
59#define RBIO_CACHE_READY_BIT 3
60
61
62#define RBIO_CACHE_SIZE 1024
63
64struct btrfs_raid_bio {
65 struct btrfs_fs_info *fs_info;
66 struct btrfs_bio *bbio;
67
68 /*
69 * logical block numbers for the start of each stripe
70 * The last one or two are p/q. These are sorted,
71 * so raid_map[0] is the start of our full stripe
72 */
73 u64 *raid_map;
74
75 /* while we're doing rmw on a stripe
76 * we put it into a hash table so we can
77 * lock the stripe and merge more rbios
78 * into it.
79 */
80 struct list_head hash_list;
81
82 /*
83 * LRU list for the stripe cache
84 */
85 struct list_head stripe_cache;
86
87 /*
88 * for scheduling work in the helper threads
89 */
90 struct btrfs_work work;
91
92 /*
93 * bio list and bio_list_lock are used
94 * to add more bios into the stripe
95 * in hopes of avoiding the full rmw
96 */
97 struct bio_list bio_list;
98 spinlock_t bio_list_lock;
99
100 /* also protected by the bio_list_lock, the
101 * plug list is used by the plugging code
102 * to collect partial bios while plugged. The
103 * stripe locking code also uses it to hand off
104 * the stripe lock to the next pending IO
105 */
106 struct list_head plug_list;
107
108 /*
109 * flags that tell us if it is safe to
110 * merge with this bio
111 */
112 unsigned long flags;
113
114 /* size of each individual stripe on disk */
115 int stripe_len;
116
117 /* number of data stripes (no p/q) */
118 int nr_data;
119
120 /*
121 * set if we're doing a parity rebuild
122 * for a read from higher up, which is handled
123 * differently from a parity rebuild as part of
124 * rmw
125 */
126 int read_rebuild;
127
128 /* first bad stripe */
129 int faila;
130
131 /* second bad stripe (for raid6 use) */
132 int failb;
133
134 /*
135 * number of pages needed to represent the full
136 * stripe
137 */
138 int nr_pages;
139
140 /*
141 * size of all the bios in the bio_list. This
142 * helps us decide if the rbio maps to a full
143 * stripe or not
144 */
145 int bio_list_bytes;
146
147 atomic_t refs;
148
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
167static int __raid56_parity_recover(struct btrfs_raid_bio *rbio);
168static noinline void finish_rmw(struct btrfs_raid_bio *rbio);
169static void rmw_work(struct btrfs_work *work);
170static void read_rebuild_work(struct btrfs_work *work);
171static void async_rmw_stripe(struct btrfs_raid_bio *rbio);
172static void async_read_rebuild(struct btrfs_raid_bio *rbio);
173static int fail_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio);
174static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed);
175static void __free_raid_bio(struct btrfs_raid_bio *rbio);
176static void index_rbio_pages(struct btrfs_raid_bio *rbio);
177static int alloc_rbio_pages(struct btrfs_raid_bio *rbio);
178
179/*
180 * the stripe hash table is used for locking, and to collect
181 * bios in hopes of making a full stripe
182 */
183int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info)
184{
185 struct btrfs_stripe_hash_table *table;
186 struct btrfs_stripe_hash_table *x;
187 struct btrfs_stripe_hash *cur;
188 struct btrfs_stripe_hash *h;
189 int num_entries = 1 << BTRFS_STRIPE_HASH_TABLE_BITS;
190 int i;
191 int table_size;
192
193 if (info->stripe_hash_table)
194 return 0;
195
196 /*
197 * The table is large, starting with order 4 and can go as high as
198 * order 7 in case lock debugging is turned on.
199 *
200 * Try harder to allocate and fallback to vmalloc to lower the chance
201 * of a failing mount.
202 */
203 table_size = sizeof(*table) + sizeof(*h) * num_entries;
204 table = kzalloc(table_size, GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
205 if (!table) {
206 table = vzalloc(table_size);
207 if (!table)
208 return -ENOMEM;
209 }
210
211 spin_lock_init(&table->cache_lock);
212 INIT_LIST_HEAD(&table->stripe_cache);
213
214 h = table->table;
215
216 for (i = 0; i < num_entries; i++) {
217 cur = h + i;
218 INIT_LIST_HEAD(&cur->hash_list);
219 spin_lock_init(&cur->lock);
220 init_waitqueue_head(&cur->wait);
221 }
222
223 x = cmpxchg(&info->stripe_hash_table, NULL, table);
224 if (x) {
225 if (is_vmalloc_addr(x))
226 vfree(x);
227 else
228 kfree(x);
229 }
230 return 0;
231}
232
233/*
234 * caching an rbio means to copy anything from the
235 * bio_pages array into the stripe_pages array. We
236 * use the page uptodate bit in the stripe cache array
237 * to indicate if it has valid data
238 *
239 * once the caching is done, we set the cache ready
240 * bit.
241 */
242static void cache_rbio_pages(struct btrfs_raid_bio *rbio)
243{
244 int i;
245 char *s;
246 char *d;
247 int ret;
248
249 ret = alloc_rbio_pages(rbio);
250 if (ret)
251 return;
252
253 for (i = 0; i < rbio->nr_pages; i++) {
254 if (!rbio->bio_pages[i])
255 continue;
256
257 s = kmap(rbio->bio_pages[i]);
258 d = kmap(rbio->stripe_pages[i]);
259
260 memcpy(d, s, PAGE_CACHE_SIZE);
261
262 kunmap(rbio->bio_pages[i]);
263 kunmap(rbio->stripe_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->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 bio_list_init(&victim->bio_list);
328}
329
330/*
331 * used to prune items that are in the cache. The caller
332 * must hold the hash table lock.
333 */
334static void __remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
335{
336 int bucket = rbio_bucket(rbio);
337 struct btrfs_stripe_hash_table *table;
338 struct btrfs_stripe_hash *h;
339 int freeit = 0;
340
341 /*
342 * check the bit again under the hash table lock.
343 */
344 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
345 return;
346
347 table = rbio->fs_info->stripe_hash_table;
348 h = table->table + bucket;
349
350 /* hold the lock for the bucket because we may be
351 * removing it from the hash table
352 */
353 spin_lock(&h->lock);
354
355 /*
356 * hold the lock for the bio list because we need
357 * to make sure the bio list is empty
358 */
359 spin_lock(&rbio->bio_list_lock);
360
361 if (test_and_clear_bit(RBIO_CACHE_BIT, &rbio->flags)) {
362 list_del_init(&rbio->stripe_cache);
363 table->cache_size -= 1;
364 freeit = 1;
365
366 /* if the bio list isn't empty, this rbio is
367 * still involved in an IO. We take it out
368 * of the cache list, and drop the ref that
369 * was held for the list.
370 *
371 * If the bio_list was empty, we also remove
372 * the rbio from the hash_table, and drop
373 * the corresponding ref
374 */
375 if (bio_list_empty(&rbio->bio_list)) {
376 if (!list_empty(&rbio->hash_list)) {
377 list_del_init(&rbio->hash_list);
378 atomic_dec(&rbio->refs);
379 BUG_ON(!list_empty(&rbio->plug_list));
380 }
381 }
382 }
383
384 spin_unlock(&rbio->bio_list_lock);
385 spin_unlock(&h->lock);
386
387 if (freeit)
388 __free_raid_bio(rbio);
389}
390
391/*
392 * prune a given rbio from the cache
393 */
394static void remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
395{
396 struct btrfs_stripe_hash_table *table;
397 unsigned long flags;
398
399 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
400 return;
401
402 table = rbio->fs_info->stripe_hash_table;
403
404 spin_lock_irqsave(&table->cache_lock, flags);
405 __remove_rbio_from_cache(rbio);
406 spin_unlock_irqrestore(&table->cache_lock, flags);
407}
408
409/*
410 * remove everything in the cache
411 */
412static void btrfs_clear_rbio_cache(struct btrfs_fs_info *info)
413{
414 struct btrfs_stripe_hash_table *table;
415 unsigned long flags;
416 struct btrfs_raid_bio *rbio;
417
418 table = info->stripe_hash_table;
419
420 spin_lock_irqsave(&table->cache_lock, flags);
421 while (!list_empty(&table->stripe_cache)) {
422 rbio = list_entry(table->stripe_cache.next,
423 struct btrfs_raid_bio,
424 stripe_cache);
425 __remove_rbio_from_cache(rbio);
426 }
427 spin_unlock_irqrestore(&table->cache_lock, flags);
428}
429
430/*
431 * remove all cached entries and free the hash table
432 * used by unmount
433 */
434void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info)
435{
436 if (!info->stripe_hash_table)
437 return;
438 btrfs_clear_rbio_cache(info);
439 if (is_vmalloc_addr(info->stripe_hash_table))
440 vfree(info->stripe_hash_table);
441 else
442 kfree(info->stripe_hash_table);
443 info->stripe_hash_table = NULL;
444}
445
446/*
447 * insert an rbio into the stripe cache. It
448 * must have already been prepared by calling
449 * cache_rbio_pages
450 *
451 * If this rbio was already cached, it gets
452 * moved to the front of the lru.
453 *
454 * If the size of the rbio cache is too big, we
455 * prune an item.
456 */
457static void cache_rbio(struct btrfs_raid_bio *rbio)
458{
459 struct btrfs_stripe_hash_table *table;
460 unsigned long flags;
461
462 if (!test_bit(RBIO_CACHE_READY_BIT, &rbio->flags))
463 return;
464
465 table = rbio->fs_info->stripe_hash_table;
466
467 spin_lock_irqsave(&table->cache_lock, flags);
468 spin_lock(&rbio->bio_list_lock);
469
470 /* bump our ref if we were not in the list before */
471 if (!test_and_set_bit(RBIO_CACHE_BIT, &rbio->flags))
472 atomic_inc(&rbio->refs);
473
474 if (!list_empty(&rbio->stripe_cache)){
475 list_move(&rbio->stripe_cache, &table->stripe_cache);
476 } else {
477 list_add(&rbio->stripe_cache, &table->stripe_cache);
478 table->cache_size += 1;
479 }
480
481 spin_unlock(&rbio->bio_list_lock);
482
483 if (table->cache_size > RBIO_CACHE_SIZE) {
484 struct btrfs_raid_bio *found;
485
486 found = list_entry(table->stripe_cache.prev,
487 struct btrfs_raid_bio,
488 stripe_cache);
489
490 if (found != rbio)
491 __remove_rbio_from_cache(found);
492 }
493
494 spin_unlock_irqrestore(&table->cache_lock, flags);
495 return;
496}
497
498/*
499 * helper function to run the xor_blocks api. It is only
500 * able to do MAX_XOR_BLOCKS at a time, so we need to
501 * loop through.
502 */
503static void run_xor(void **pages, int src_cnt, ssize_t len)
504{
505 int src_off = 0;
506 int xor_src_cnt = 0;
507 void *dest = pages[src_cnt];
508
509 while(src_cnt > 0) {
510 xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS);
511 xor_blocks(xor_src_cnt, len, dest, pages + src_off);
512
513 src_cnt -= xor_src_cnt;
514 src_off += xor_src_cnt;
515 }
516}
517
518/*
519 * returns true if the bio list inside this rbio
520 * covers an entire stripe (no rmw required).
521 * Must be called with the bio list lock held, or
522 * at a time when you know it is impossible to add
523 * new bios into the list
524 */
525static int __rbio_is_full(struct btrfs_raid_bio *rbio)
526{
527 unsigned long size = rbio->bio_list_bytes;
528 int ret = 1;
529
530 if (size != rbio->nr_data * rbio->stripe_len)
531 ret = 0;
532
533 BUG_ON(size > rbio->nr_data * rbio->stripe_len);
534 return ret;
535}
536
537static int rbio_is_full(struct btrfs_raid_bio *rbio)
538{
539 unsigned long flags;
540 int ret;
541
542 spin_lock_irqsave(&rbio->bio_list_lock, flags);
543 ret = __rbio_is_full(rbio);
544 spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
545 return ret;
546}
547
548/*
549 * returns 1 if it is safe to merge two rbios together.
550 * The merging is safe if the two rbios correspond to
551 * the same stripe and if they are both going in the same
552 * direction (read vs write), and if neither one is
553 * locked for final IO
554 *
555 * The caller is responsible for locking such that
556 * rmw_locked is safe to test
557 */
558static int rbio_can_merge(struct btrfs_raid_bio *last,
559 struct btrfs_raid_bio *cur)
560{
561 if (test_bit(RBIO_RMW_LOCKED_BIT, &last->flags) ||
562 test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags))
563 return 0;
564
565 /*
566 * we can't merge with cached rbios, since the
567 * idea is that when we merge the destination
568 * rbio is going to run our IO for us. We can
569 * steal from cached rbio's though, other functions
570 * handle that.
571 */
572 if (test_bit(RBIO_CACHE_BIT, &last->flags) ||
573 test_bit(RBIO_CACHE_BIT, &cur->flags))
574 return 0;
575
576 if (last->raid_map[0] !=
577 cur->raid_map[0])
578 return 0;
579
580 /* reads can't merge with writes */
581 if (last->read_rebuild !=
582 cur->read_rebuild) {
583 return 0;
584 }
585
586 return 1;
587}
588
589/*
590 * helper to index into the pstripe
591 */
592static struct page *rbio_pstripe_page(struct btrfs_raid_bio *rbio, int index)
593{
594 index += (rbio->nr_data * rbio->stripe_len) >> PAGE_CACHE_SHIFT;
595 return rbio->stripe_pages[index];
596}
597
598/*
599 * helper to index into the qstripe, returns null
600 * if there is no qstripe
601 */
602static struct page *rbio_qstripe_page(struct btrfs_raid_bio *rbio, int index)
603{
604 if (rbio->nr_data + 1 == rbio->bbio->num_stripes)
605 return NULL;
606
607 index += ((rbio->nr_data + 1) * rbio->stripe_len) >>
608 PAGE_CACHE_SHIFT;
609 return rbio->stripe_pages[index];
610}
611
612/*
613 * The first stripe in the table for a logical address
614 * has the lock. rbios are added in one of three ways:
615 *
616 * 1) Nobody has the stripe locked yet. The rbio is given
617 * the lock and 0 is returned. The caller must start the IO
618 * themselves.
619 *
620 * 2) Someone has the stripe locked, but we're able to merge
621 * with the lock owner. The rbio is freed and the IO will
622 * start automatically along with the existing rbio. 1 is returned.
623 *
624 * 3) Someone has the stripe locked, but we're not able to merge.
625 * The rbio is added to the lock owner's plug list, or merged into
626 * an rbio already on the plug list. When the lock owner unlocks,
627 * the next rbio on the list is run and the IO is started automatically.
628 * 1 is returned
629 *
630 * If we return 0, the caller still owns the rbio and must continue with
631 * IO submission. If we return 1, the caller must assume the rbio has
632 * already been freed.
633 */
634static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
635{
636 int bucket = rbio_bucket(rbio);
637 struct btrfs_stripe_hash *h = rbio->fs_info->stripe_hash_table->table + bucket;
638 struct btrfs_raid_bio *cur;
639 struct btrfs_raid_bio *pending;
640 unsigned long flags;
641 DEFINE_WAIT(wait);
642 struct btrfs_raid_bio *freeit = NULL;
643 struct btrfs_raid_bio *cache_drop = NULL;
644 int ret = 0;
645 int walk = 0;
646
647 spin_lock_irqsave(&h->lock, flags);
648 list_for_each_entry(cur, &h->hash_list, hash_list) {
649 walk++;
650 if (cur->raid_map[0] == rbio->raid_map[0]) {
651 spin_lock(&cur->bio_list_lock);
652
653 /* can we steal this cached rbio's pages? */
654 if (bio_list_empty(&cur->bio_list) &&
655 list_empty(&cur->plug_list) &&
656 test_bit(RBIO_CACHE_BIT, &cur->flags) &&
657 !test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) {
658 list_del_init(&cur->hash_list);
659 atomic_dec(&cur->refs);
660
661 steal_rbio(cur, rbio);
662 cache_drop = cur;
663 spin_unlock(&cur->bio_list_lock);
664
665 goto lockit;
666 }
667
668 /* can we merge into the lock owner? */
669 if (rbio_can_merge(cur, rbio)) {
670 merge_rbio(cur, rbio);
671 spin_unlock(&cur->bio_list_lock);
672 freeit = rbio;
673 ret = 1;
674 goto out;
675 }
676
677
678 /*
679 * we couldn't merge with the running
680 * rbio, see if we can merge with the
681 * pending ones. We don't have to
682 * check for rmw_locked because there
683 * is no way they are inside finish_rmw
684 * right now
685 */
686 list_for_each_entry(pending, &cur->plug_list,
687 plug_list) {
688 if (rbio_can_merge(pending, rbio)) {
689 merge_rbio(pending, rbio);
690 spin_unlock(&cur->bio_list_lock);
691 freeit = rbio;
692 ret = 1;
693 goto out;
694 }
695 }
696
697 /* no merging, put us on the tail of the plug list,
698 * our rbio will be started with the currently
699 * running rbio unlocks
700 */
701 list_add_tail(&rbio->plug_list, &cur->plug_list);
702 spin_unlock(&cur->bio_list_lock);
703 ret = 1;
704 goto out;
705 }
706 }
707lockit:
708 atomic_inc(&rbio->refs);
709 list_add(&rbio->hash_list, &h->hash_list);
710out:
711 spin_unlock_irqrestore(&h->lock, flags);
712 if (cache_drop)
713 remove_rbio_from_cache(cache_drop);
714 if (freeit)
715 __free_raid_bio(freeit);
716 return ret;
717}
718
719/*
720 * called as rmw or parity rebuild is completed. If the plug list has more
721 * rbios waiting for this stripe, the next one on the list will be started
722 */
723static noinline void unlock_stripe(struct btrfs_raid_bio *rbio)
724{
725 int bucket;
726 struct btrfs_stripe_hash *h;
727 unsigned long flags;
728 int keep_cache = 0;
729
730 bucket = rbio_bucket(rbio);
731 h = rbio->fs_info->stripe_hash_table->table + bucket;
732
733 if (list_empty(&rbio->plug_list))
734 cache_rbio(rbio);
735
736 spin_lock_irqsave(&h->lock, flags);
737 spin_lock(&rbio->bio_list_lock);
738
739 if (!list_empty(&rbio->hash_list)) {
740 /*
741 * if we're still cached and there is no other IO
742 * to perform, just leave this rbio here for others
743 * to steal from later
744 */
745 if (list_empty(&rbio->plug_list) &&
746 test_bit(RBIO_CACHE_BIT, &rbio->flags)) {
747 keep_cache = 1;
748 clear_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
749 BUG_ON(!bio_list_empty(&rbio->bio_list));
750 goto done;
751 }
752
753 list_del_init(&rbio->hash_list);
754 atomic_dec(&rbio->refs);
755
756 /*
757 * we use the plug list to hold all the rbios
758 * waiting for the chance to lock this stripe.
759 * hand the lock over to one of them.
760 */
761 if (!list_empty(&rbio->plug_list)) {
762 struct btrfs_raid_bio *next;
763 struct list_head *head = rbio->plug_list.next;
764
765 next = list_entry(head, struct btrfs_raid_bio,
766 plug_list);
767
768 list_del_init(&rbio->plug_list);
769
770 list_add(&next->hash_list, &h->hash_list);
771 atomic_inc(&next->refs);
772 spin_unlock(&rbio->bio_list_lock);
773 spin_unlock_irqrestore(&h->lock, flags);
774
775 if (next->read_rebuild)
776 async_read_rebuild(next);
777 else {
778 steal_rbio(rbio, next);
779 async_rmw_stripe(next);
780 }
781
782 goto done_nolock;
783 } else if (waitqueue_active(&h->wait)) {
784 spin_unlock(&rbio->bio_list_lock);
785 spin_unlock_irqrestore(&h->lock, flags);
786 wake_up(&h->wait);
787 goto done_nolock;
788 }
789 }
790done:
791 spin_unlock(&rbio->bio_list_lock);
792 spin_unlock_irqrestore(&h->lock, flags);
793
794done_nolock:
795 if (!keep_cache)
796 remove_rbio_from_cache(rbio);
797}
798
799static void __free_raid_bio(struct btrfs_raid_bio *rbio)
800{
801 int i;
802
803 WARN_ON(atomic_read(&rbio->refs) < 0);
804 if (!atomic_dec_and_test(&rbio->refs))
805 return;
806
807 WARN_ON(!list_empty(&rbio->stripe_cache));
808 WARN_ON(!list_empty(&rbio->hash_list));
809 WARN_ON(!bio_list_empty(&rbio->bio_list));
810
811 for (i = 0; i < rbio->nr_pages; i++) {
812 if (rbio->stripe_pages[i]) {
813 __free_page(rbio->stripe_pages[i]);
814 rbio->stripe_pages[i] = NULL;
815 }
816 }
817 kfree(rbio->raid_map);
818 kfree(rbio->bbio);
819 kfree(rbio);
820}
821
822static void free_raid_bio(struct btrfs_raid_bio *rbio)
823{
824 unlock_stripe(rbio);
825 __free_raid_bio(rbio);
826}
827
828/*
829 * this frees the rbio and runs through all the bios in the
830 * bio_list and calls end_io on them
831 */
832static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, int err, int uptodate)
833{
834 struct bio *cur = bio_list_get(&rbio->bio_list);
835 struct bio *next;
836 free_raid_bio(rbio);
837
838 while (cur) {
839 next = cur->bi_next;
840 cur->bi_next = NULL;
841 if (uptodate)
842 set_bit(BIO_UPTODATE, &cur->bi_flags);
843 bio_endio(cur, err);
844 cur = next;
845 }
846}
847
848/*
849 * end io function used by finish_rmw. When we finally
850 * get here, we've written a full stripe
851 */
852static void raid_write_end_io(struct bio *bio, int err)
853{
854 struct btrfs_raid_bio *rbio = bio->bi_private;
855
856 if (err)
857 fail_bio_stripe(rbio, bio);
858
859 bio_put(bio);
860
861 if (!atomic_dec_and_test(&rbio->bbio->stripes_pending))
862 return;
863
864 err = 0;
865
866 /* OK, we have read all the stripes we need to. */
867 if (atomic_read(&rbio->bbio->error) > rbio->bbio->max_errors)
868 err = -EIO;
869
870 rbio_orig_end_io(rbio, err, 0);
871 return;
872}
873
874/*
875 * the read/modify/write code wants to use the original bio for
876 * any pages it included, and then use the rbio for everything
877 * else. This function decides if a given index (stripe number)
878 * and page number in that stripe fall inside the original bio
879 * or the rbio.
880 *
881 * if you set bio_list_only, you'll get a NULL back for any ranges
882 * that are outside the bio_list
883 *
884 * This doesn't take any refs on anything, you get a bare page pointer
885 * and the caller must bump refs as required.
886 *
887 * You must call index_rbio_pages once before you can trust
888 * the answers from this function.
889 */
890static struct page *page_in_rbio(struct btrfs_raid_bio *rbio,
891 int index, int pagenr, int bio_list_only)
892{
893 int chunk_page;
894 struct page *p = NULL;
895
896 chunk_page = index * (rbio->stripe_len >> PAGE_SHIFT) + pagenr;
897
898 spin_lock_irq(&rbio->bio_list_lock);
899 p = rbio->bio_pages[chunk_page];
900 spin_unlock_irq(&rbio->bio_list_lock);
901
902 if (p || bio_list_only)
903 return p;
904
905 return rbio->stripe_pages[chunk_page];
906}
907
908/*
909 * number of pages we need for the entire stripe across all the
910 * drives
911 */
912static unsigned long rbio_nr_pages(unsigned long stripe_len, int nr_stripes)
913{
914 unsigned long nr = stripe_len * nr_stripes;
915 return (nr + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
916}
917
918/*
919 * allocation and initial setup for the btrfs_raid_bio. Not
920 * this does not allocate any pages for rbio->pages.
921 */
922static struct btrfs_raid_bio *alloc_rbio(struct btrfs_root *root,
923 struct btrfs_bio *bbio, u64 *raid_map,
924 u64 stripe_len)
925{
926 struct btrfs_raid_bio *rbio;
927 int nr_data = 0;
928 int num_pages = rbio_nr_pages(stripe_len, bbio->num_stripes);
929 void *p;
930
931 rbio = kzalloc(sizeof(*rbio) + num_pages * sizeof(struct page *) * 2,
932 GFP_NOFS);
933 if (!rbio) {
934 kfree(raid_map);
935 kfree(bbio);
936 return ERR_PTR(-ENOMEM);
937 }
938
939 bio_list_init(&rbio->bio_list);
940 INIT_LIST_HEAD(&rbio->plug_list);
941 spin_lock_init(&rbio->bio_list_lock);
942 INIT_LIST_HEAD(&rbio->stripe_cache);
943 INIT_LIST_HEAD(&rbio->hash_list);
944 rbio->bbio = bbio;
945 rbio->raid_map = raid_map;
946 rbio->fs_info = root->fs_info;
947 rbio->stripe_len = stripe_len;
948 rbio->nr_pages = num_pages;
949 rbio->faila = -1;
950 rbio->failb = -1;
951 atomic_set(&rbio->refs, 1);
952
953 /*
954 * the stripe_pages and bio_pages array point to the extra
955 * memory we allocated past the end of the rbio
956 */
957 p = rbio + 1;
958 rbio->stripe_pages = p;
959 rbio->bio_pages = p + sizeof(struct page *) * num_pages;
960
961 if (raid_map[bbio->num_stripes - 1] == RAID6_Q_STRIPE)
962 nr_data = bbio->num_stripes - 2;
963 else
964 nr_data = bbio->num_stripes - 1;
965
966 rbio->nr_data = nr_data;
967 return rbio;
968}
969
970/* allocate pages for all the stripes in the bio, including parity */
971static int alloc_rbio_pages(struct btrfs_raid_bio *rbio)
972{
973 int i;
974 struct page *page;
975
976 for (i = 0; i < rbio->nr_pages; i++) {
977 if (rbio->stripe_pages[i])
978 continue;
979 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
980 if (!page)
981 return -ENOMEM;
982 rbio->stripe_pages[i] = page;
983 ClearPageUptodate(page);
984 }
985 return 0;
986}
987
988/* allocate pages for just the p/q stripes */
989static int alloc_rbio_parity_pages(struct btrfs_raid_bio *rbio)
990{
991 int i;
992 struct page *page;
993
994 i = (rbio->nr_data * rbio->stripe_len) >> PAGE_CACHE_SHIFT;
995
996 for (; i < rbio->nr_pages; i++) {
997 if (rbio->stripe_pages[i])
998 continue;
999 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1000 if (!page)
1001 return -ENOMEM;
1002 rbio->stripe_pages[i] = page;
1003 }
1004 return 0;
1005}
1006
1007/*
1008 * add a single page from a specific stripe into our list of bios for IO
1009 * this will try to merge into existing bios if possible, and returns
1010 * zero if all went well.
1011 */
1012static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
1013 struct bio_list *bio_list,
1014 struct page *page,
1015 int stripe_nr,
1016 unsigned long page_index,
1017 unsigned long bio_max_len)
1018{
1019 struct bio *last = bio_list->tail;
1020 u64 last_end = 0;
1021 int ret;
1022 struct bio *bio;
1023 struct btrfs_bio_stripe *stripe;
1024 u64 disk_start;
1025
1026 stripe = &rbio->bbio->stripes[stripe_nr];
1027 disk_start = stripe->physical + (page_index << PAGE_CACHE_SHIFT);
1028
1029 /* if the device is missing, just fail this stripe */
1030 if (!stripe->dev->bdev)
1031 return fail_rbio_index(rbio, stripe_nr);
1032
1033 /* see if we can add this page onto our existing bio */
1034 if (last) {
1035 last_end = (u64)last->bi_iter.bi_sector << 9;
1036 last_end += last->bi_iter.bi_size;
1037
1038 /*
1039 * we can't merge these if they are from different
1040 * devices or if they are not contiguous
1041 */
1042 if (last_end == disk_start && stripe->dev->bdev &&
1043 test_bit(BIO_UPTODATE, &last->bi_flags) &&
1044 last->bi_bdev == stripe->dev->bdev) {
1045 ret = bio_add_page(last, page, PAGE_CACHE_SIZE, 0);
1046 if (ret == PAGE_CACHE_SIZE)
1047 return 0;
1048 }
1049 }
1050
1051 /* put a new bio on the list */
1052 bio = btrfs_io_bio_alloc(GFP_NOFS, bio_max_len >> PAGE_SHIFT?:1);
1053 if (!bio)
1054 return -ENOMEM;
1055
1056 bio->bi_iter.bi_size = 0;
1057 bio->bi_bdev = stripe->dev->bdev;
1058 bio->bi_iter.bi_sector = disk_start >> 9;
1059 set_bit(BIO_UPTODATE, &bio->bi_flags);
1060
1061 bio_add_page(bio, page, PAGE_CACHE_SIZE, 0);
1062 bio_list_add(bio_list, bio);
1063 return 0;
1064}
1065
1066/*
1067 * while we're doing the read/modify/write cycle, we could
1068 * have errors in reading pages off the disk. This checks
1069 * for errors and if we're not able to read the page it'll
1070 * trigger parity reconstruction. The rmw will be finished
1071 * after we've reconstructed the failed stripes
1072 */
1073static void validate_rbio_for_rmw(struct btrfs_raid_bio *rbio)
1074{
1075 if (rbio->faila >= 0 || rbio->failb >= 0) {
1076 BUG_ON(rbio->faila == rbio->bbio->num_stripes - 1);
1077 __raid56_parity_recover(rbio);
1078 } else {
1079 finish_rmw(rbio);
1080 }
1081}
1082
1083/*
1084 * these are just the pages from the rbio array, not from anything
1085 * the FS sent down to us
1086 */
1087static struct page *rbio_stripe_page(struct btrfs_raid_bio *rbio, int stripe, int page)
1088{
1089 int index;
1090 index = stripe * (rbio->stripe_len >> PAGE_CACHE_SHIFT);
1091 index += page;
1092 return rbio->stripe_pages[index];
1093}
1094
1095/*
1096 * helper function to walk our bio list and populate the bio_pages array with
1097 * the result. This seems expensive, but it is faster than constantly
1098 * searching through the bio list as we setup the IO in finish_rmw or stripe
1099 * reconstruction.
1100 *
1101 * This must be called before you trust the answers from page_in_rbio
1102 */
1103static void index_rbio_pages(struct btrfs_raid_bio *rbio)
1104{
1105 struct bio *bio;
1106 u64 start;
1107 unsigned long stripe_offset;
1108 unsigned long page_index;
1109 struct page *p;
1110 int i;
1111
1112 spin_lock_irq(&rbio->bio_list_lock);
1113 bio_list_for_each(bio, &rbio->bio_list) {
1114 start = (u64)bio->bi_iter.bi_sector << 9;
1115 stripe_offset = start - rbio->raid_map[0];
1116 page_index = stripe_offset >> PAGE_CACHE_SHIFT;
1117
1118 for (i = 0; i < bio->bi_vcnt; i++) {
1119 p = bio->bi_io_vec[i].bv_page;
1120 rbio->bio_pages[page_index + i] = p;
1121 }
1122 }
1123 spin_unlock_irq(&rbio->bio_list_lock);
1124}
1125
1126/*
1127 * this is called from one of two situations. We either
1128 * have a full stripe from the higher layers, or we've read all
1129 * the missing bits off disk.
1130 *
1131 * This will calculate the parity and then send down any
1132 * changed blocks.
1133 */
1134static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
1135{
1136 struct btrfs_bio *bbio = rbio->bbio;
1137 void *pointers[bbio->num_stripes];
1138 int stripe_len = rbio->stripe_len;
1139 int nr_data = rbio->nr_data;
1140 int stripe;
1141 int pagenr;
1142 int p_stripe = -1;
1143 int q_stripe = -1;
1144 struct bio_list bio_list;
1145 struct bio *bio;
1146 int pages_per_stripe = stripe_len >> PAGE_CACHE_SHIFT;
1147 int ret;
1148
1149 bio_list_init(&bio_list);
1150
1151 if (bbio->num_stripes - rbio->nr_data == 1) {
1152 p_stripe = bbio->num_stripes - 1;
1153 } else if (bbio->num_stripes - rbio->nr_data == 2) {
1154 p_stripe = bbio->num_stripes - 2;
1155 q_stripe = bbio->num_stripes - 1;
1156 } else {
1157 BUG();
1158 }
1159
1160 /* at this point we either have a full stripe,
1161 * or we've read the full stripe from the drive.
1162 * recalculate the parity and write the new results.
1163 *
1164 * We're not allowed to add any new bios to the
1165 * bio list here, anyone else that wants to
1166 * change this stripe needs to do their own rmw.
1167 */
1168 spin_lock_irq(&rbio->bio_list_lock);
1169 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1170 spin_unlock_irq(&rbio->bio_list_lock);
1171
1172 atomic_set(&rbio->bbio->error, 0);
1173
1174 /*
1175 * now that we've set rmw_locked, run through the
1176 * bio list one last time and map the page pointers
1177 *
1178 * We don't cache full rbios because we're assuming
1179 * the higher layers are unlikely to use this area of
1180 * the disk again soon. If they do use it again,
1181 * hopefully they will send another full bio.
1182 */
1183 index_rbio_pages(rbio);
1184 if (!rbio_is_full(rbio))
1185 cache_rbio_pages(rbio);
1186 else
1187 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
1188
1189 for (pagenr = 0; pagenr < pages_per_stripe; pagenr++) {
1190 struct page *p;
1191 /* first collect one page from each data stripe */
1192 for (stripe = 0; stripe < nr_data; stripe++) {
1193 p = page_in_rbio(rbio, stripe, pagenr, 0);
1194 pointers[stripe] = kmap(p);
1195 }
1196
1197 /* then add the parity stripe */
1198 p = rbio_pstripe_page(rbio, pagenr);
1199 SetPageUptodate(p);
1200 pointers[stripe++] = kmap(p);
1201
1202 if (q_stripe != -1) {
1203
1204 /*
1205 * raid6, add the qstripe and call the
1206 * library function to fill in our p/q
1207 */
1208 p = rbio_qstripe_page(rbio, pagenr);
1209 SetPageUptodate(p);
1210 pointers[stripe++] = kmap(p);
1211
1212 raid6_call.gen_syndrome(bbio->num_stripes, PAGE_SIZE,
1213 pointers);
1214 } else {
1215 /* raid5 */
1216 memcpy(pointers[nr_data], pointers[0], PAGE_SIZE);
1217 run_xor(pointers + 1, nr_data - 1, PAGE_CACHE_SIZE);
1218 }
1219
1220
1221 for (stripe = 0; stripe < bbio->num_stripes; stripe++)
1222 kunmap(page_in_rbio(rbio, stripe, pagenr, 0));
1223 }
1224
1225 /*
1226 * time to start writing. Make bios for everything from the
1227 * higher layers (the bio_list in our rbio) and our p/q. Ignore
1228 * everything else.
1229 */
1230 for (stripe = 0; stripe < bbio->num_stripes; stripe++) {
1231 for (pagenr = 0; pagenr < pages_per_stripe; pagenr++) {
1232 struct page *page;
1233 if (stripe < rbio->nr_data) {
1234 page = page_in_rbio(rbio, stripe, pagenr, 1);
1235 if (!page)
1236 continue;
1237 } else {
1238 page = rbio_stripe_page(rbio, stripe, pagenr);
1239 }
1240
1241 ret = rbio_add_io_page(rbio, &bio_list,
1242 page, stripe, pagenr, rbio->stripe_len);
1243 if (ret)
1244 goto cleanup;
1245 }
1246 }
1247
1248 atomic_set(&bbio->stripes_pending, bio_list_size(&bio_list));
1249 BUG_ON(atomic_read(&bbio->stripes_pending) == 0);
1250
1251 while (1) {
1252 bio = bio_list_pop(&bio_list);
1253 if (!bio)
1254 break;
1255
1256 bio->bi_private = rbio;
1257 bio->bi_end_io = raid_write_end_io;
1258 BUG_ON(!test_bit(BIO_UPTODATE, &bio->bi_flags));
1259 submit_bio(WRITE, bio);
1260 }
1261 return;
1262
1263cleanup:
1264 rbio_orig_end_io(rbio, -EIO, 0);
1265}
1266
1267/*
1268 * helper to find the stripe number for a given bio. Used to figure out which
1269 * stripe has failed. This expects the bio to correspond to a physical disk,
1270 * so it looks up based on physical sector numbers.
1271 */
1272static int find_bio_stripe(struct btrfs_raid_bio *rbio,
1273 struct bio *bio)
1274{
1275 u64 physical = bio->bi_iter.bi_sector;
1276 u64 stripe_start;
1277 int i;
1278 struct btrfs_bio_stripe *stripe;
1279
1280 physical <<= 9;
1281
1282 for (i = 0; i < rbio->bbio->num_stripes; i++) {
1283 stripe = &rbio->bbio->stripes[i];
1284 stripe_start = stripe->physical;
1285 if (physical >= stripe_start &&
1286 physical < stripe_start + rbio->stripe_len) {
1287 return i;
1288 }
1289 }
1290 return -1;
1291}
1292
1293/*
1294 * helper to find the stripe number for a given
1295 * bio (before mapping). Used to figure out which stripe has
1296 * failed. This looks up based on logical block numbers.
1297 */
1298static int find_logical_bio_stripe(struct btrfs_raid_bio *rbio,
1299 struct bio *bio)
1300{
1301 u64 logical = bio->bi_iter.bi_sector;
1302 u64 stripe_start;
1303 int i;
1304
1305 logical <<= 9;
1306
1307 for (i = 0; i < rbio->nr_data; i++) {
1308 stripe_start = rbio->raid_map[i];
1309 if (logical >= stripe_start &&
1310 logical < stripe_start + rbio->stripe_len) {
1311 return i;
1312 }
1313 }
1314 return -1;
1315}
1316
1317/*
1318 * returns -EIO if we had too many failures
1319 */
1320static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed)
1321{
1322 unsigned long flags;
1323 int ret = 0;
1324
1325 spin_lock_irqsave(&rbio->bio_list_lock, flags);
1326
1327 /* we already know this stripe is bad, move on */
1328 if (rbio->faila == failed || rbio->failb == failed)
1329 goto out;
1330
1331 if (rbio->faila == -1) {
1332 /* first failure on this rbio */
1333 rbio->faila = failed;
1334 atomic_inc(&rbio->bbio->error);
1335 } else if (rbio->failb == -1) {
1336 /* second failure on this rbio */
1337 rbio->failb = failed;
1338 atomic_inc(&rbio->bbio->error);
1339 } else {
1340 ret = -EIO;
1341 }
1342out:
1343 spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
1344
1345 return ret;
1346}
1347
1348/*
1349 * helper to fail a stripe based on a physical disk
1350 * bio.
1351 */
1352static int fail_bio_stripe(struct btrfs_raid_bio *rbio,
1353 struct bio *bio)
1354{
1355 int failed = find_bio_stripe(rbio, bio);
1356
1357 if (failed < 0)
1358 return -EIO;
1359
1360 return fail_rbio_index(rbio, failed);
1361}
1362
1363/*
1364 * this sets each page in the bio uptodate. It should only be used on private
1365 * rbio pages, nothing that comes in from the higher layers
1366 */
1367static void set_bio_pages_uptodate(struct bio *bio)
1368{
1369 int i;
1370 struct page *p;
1371
1372 for (i = 0; i < bio->bi_vcnt; i++) {
1373 p = bio->bi_io_vec[i].bv_page;
1374 SetPageUptodate(p);
1375 }
1376}
1377
1378/*
1379 * end io for the read phase of the rmw cycle. All the bios here are physical
1380 * stripe bios we've read from the disk so we can recalculate the parity of the
1381 * stripe.
1382 *
1383 * This will usually kick off finish_rmw once all the bios are read in, but it
1384 * may trigger parity reconstruction if we had any errors along the way
1385 */
1386static void raid_rmw_end_io(struct bio *bio, int err)
1387{
1388 struct btrfs_raid_bio *rbio = bio->bi_private;
1389
1390 if (err)
1391 fail_bio_stripe(rbio, bio);
1392 else
1393 set_bio_pages_uptodate(bio);
1394
1395 bio_put(bio);
1396
1397 if (!atomic_dec_and_test(&rbio->bbio->stripes_pending))
1398 return;
1399
1400 err = 0;
1401 if (atomic_read(&rbio->bbio->error) > rbio->bbio->max_errors)
1402 goto cleanup;
1403
1404 /*
1405 * this will normally call finish_rmw to start our write
1406 * but if there are any failed stripes we'll reconstruct
1407 * from parity first
1408 */
1409 validate_rbio_for_rmw(rbio);
1410 return;
1411
1412cleanup:
1413
1414 rbio_orig_end_io(rbio, -EIO, 0);
1415}
1416
1417static void async_rmw_stripe(struct btrfs_raid_bio *rbio)
1418{
1419 btrfs_init_work(&rbio->work, rmw_work, NULL, NULL);
1420
1421 btrfs_queue_work(rbio->fs_info->rmw_workers,
1422 &rbio->work);
1423}
1424
1425static void async_read_rebuild(struct btrfs_raid_bio *rbio)
1426{
1427 btrfs_init_work(&rbio->work, read_rebuild_work, NULL, NULL);
1428
1429 btrfs_queue_work(rbio->fs_info->rmw_workers,
1430 &rbio->work);
1431}
1432
1433/*
1434 * the stripe must be locked by the caller. It will
1435 * unlock after all the writes are done
1436 */
1437static int raid56_rmw_stripe(struct btrfs_raid_bio *rbio)
1438{
1439 int bios_to_read = 0;
1440 struct btrfs_bio *bbio = rbio->bbio;
1441 struct bio_list bio_list;
1442 int ret;
1443 int nr_pages = (rbio->stripe_len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1444 int pagenr;
1445 int stripe;
1446 struct bio *bio;
1447
1448 bio_list_init(&bio_list);
1449
1450 ret = alloc_rbio_pages(rbio);
1451 if (ret)
1452 goto cleanup;
1453
1454 index_rbio_pages(rbio);
1455
1456 atomic_set(&rbio->bbio->error, 0);
1457 /*
1458 * build a list of bios to read all the missing parts of this
1459 * stripe
1460 */
1461 for (stripe = 0; stripe < rbio->nr_data; stripe++) {
1462 for (pagenr = 0; pagenr < nr_pages; pagenr++) {
1463 struct page *page;
1464 /*
1465 * we want to find all the pages missing from
1466 * the rbio and read them from the disk. If
1467 * page_in_rbio finds a page in the bio list
1468 * we don't need to read it off the stripe.
1469 */
1470 page = page_in_rbio(rbio, stripe, pagenr, 1);
1471 if (page)
1472 continue;
1473
1474 page = rbio_stripe_page(rbio, stripe, pagenr);
1475 /*
1476 * the bio cache may have handed us an uptodate
1477 * page. If so, be happy and use it
1478 */
1479 if (PageUptodate(page))
1480 continue;
1481
1482 ret = rbio_add_io_page(rbio, &bio_list, page,
1483 stripe, pagenr, rbio->stripe_len);
1484 if (ret)
1485 goto cleanup;
1486 }
1487 }
1488
1489 bios_to_read = bio_list_size(&bio_list);
1490 if (!bios_to_read) {
1491 /*
1492 * this can happen if others have merged with
1493 * us, it means there is nothing left to read.
1494 * But if there are missing devices it may not be
1495 * safe to do the full stripe write yet.
1496 */
1497 goto finish;
1498 }
1499
1500 /*
1501 * the bbio may be freed once we submit the last bio. Make sure
1502 * not to touch it after that
1503 */
1504 atomic_set(&bbio->stripes_pending, bios_to_read);
1505 while (1) {
1506 bio = bio_list_pop(&bio_list);
1507 if (!bio)
1508 break;
1509
1510 bio->bi_private = rbio;
1511 bio->bi_end_io = raid_rmw_end_io;
1512
1513 btrfs_bio_wq_end_io(rbio->fs_info, bio,
1514 BTRFS_WQ_ENDIO_RAID56);
1515
1516 BUG_ON(!test_bit(BIO_UPTODATE, &bio->bi_flags));
1517 submit_bio(READ, bio);
1518 }
1519 /* the actual write will happen once the reads are done */
1520 return 0;
1521
1522cleanup:
1523 rbio_orig_end_io(rbio, -EIO, 0);
1524 return -EIO;
1525
1526finish:
1527 validate_rbio_for_rmw(rbio);
1528 return 0;
1529}
1530
1531/*
1532 * if the upper layers pass in a full stripe, we thank them by only allocating
1533 * enough pages to hold the parity, and sending it all down quickly.
1534 */
1535static int full_stripe_write(struct btrfs_raid_bio *rbio)
1536{
1537 int ret;
1538
1539 ret = alloc_rbio_parity_pages(rbio);
1540 if (ret) {
1541 __free_raid_bio(rbio);
1542 return ret;
1543 }
1544
1545 ret = lock_stripe_add(rbio);
1546 if (ret == 0)
1547 finish_rmw(rbio);
1548 return 0;
1549}
1550
1551/*
1552 * partial stripe writes get handed over to async helpers.
1553 * We're really hoping to merge a few more writes into this
1554 * rbio before calculating new parity
1555 */
1556static int partial_stripe_write(struct btrfs_raid_bio *rbio)
1557{
1558 int ret;
1559
1560 ret = lock_stripe_add(rbio);
1561 if (ret == 0)
1562 async_rmw_stripe(rbio);
1563 return 0;
1564}
1565
1566/*
1567 * sometimes while we were reading from the drive to
1568 * recalculate parity, enough new bios come into create
1569 * a full stripe. So we do a check here to see if we can
1570 * go directly to finish_rmw
1571 */
1572static int __raid56_parity_write(struct btrfs_raid_bio *rbio)
1573{
1574 /* head off into rmw land if we don't have a full stripe */
1575 if (!rbio_is_full(rbio))
1576 return partial_stripe_write(rbio);
1577 return full_stripe_write(rbio);
1578}
1579
1580/*
1581 * We use plugging call backs to collect full stripes.
1582 * Any time we get a partial stripe write while plugged
1583 * we collect it into a list. When the unplug comes down,
1584 * we sort the list by logical block number and merge
1585 * everything we can into the same rbios
1586 */
1587struct btrfs_plug_cb {
1588 struct blk_plug_cb cb;
1589 struct btrfs_fs_info *info;
1590 struct list_head rbio_list;
1591 struct btrfs_work work;
1592};
1593
1594/*
1595 * rbios on the plug list are sorted for easier merging.
1596 */
1597static int plug_cmp(void *priv, struct list_head *a, struct list_head *b)
1598{
1599 struct btrfs_raid_bio *ra = container_of(a, struct btrfs_raid_bio,
1600 plug_list);
1601 struct btrfs_raid_bio *rb = container_of(b, struct btrfs_raid_bio,
1602 plug_list);
1603 u64 a_sector = ra->bio_list.head->bi_iter.bi_sector;
1604 u64 b_sector = rb->bio_list.head->bi_iter.bi_sector;
1605
1606 if (a_sector < b_sector)
1607 return -1;
1608 if (a_sector > b_sector)
1609 return 1;
1610 return 0;
1611}
1612
1613static void run_plug(struct btrfs_plug_cb *plug)
1614{
1615 struct btrfs_raid_bio *cur;
1616 struct btrfs_raid_bio *last = NULL;
1617
1618 /*
1619 * sort our plug list then try to merge
1620 * everything we can in hopes of creating full
1621 * stripes.
1622 */
1623 list_sort(NULL, &plug->rbio_list, plug_cmp);
1624 while (!list_empty(&plug->rbio_list)) {
1625 cur = list_entry(plug->rbio_list.next,
1626 struct btrfs_raid_bio, plug_list);
1627 list_del_init(&cur->plug_list);
1628
1629 if (rbio_is_full(cur)) {
1630 /* we have a full stripe, send it down */
1631 full_stripe_write(cur);
1632 continue;
1633 }
1634 if (last) {
1635 if (rbio_can_merge(last, cur)) {
1636 merge_rbio(last, cur);
1637 __free_raid_bio(cur);
1638 continue;
1639
1640 }
1641 __raid56_parity_write(last);
1642 }
1643 last = cur;
1644 }
1645 if (last) {
1646 __raid56_parity_write(last);
1647 }
1648 kfree(plug);
1649}
1650
1651/*
1652 * if the unplug comes from schedule, we have to push the
1653 * work off to a helper thread
1654 */
1655static void unplug_work(struct btrfs_work *work)
1656{
1657 struct btrfs_plug_cb *plug;
1658 plug = container_of(work, struct btrfs_plug_cb, work);
1659 run_plug(plug);
1660}
1661
1662static void btrfs_raid_unplug(struct blk_plug_cb *cb, bool from_schedule)
1663{
1664 struct btrfs_plug_cb *plug;
1665 plug = container_of(cb, struct btrfs_plug_cb, cb);
1666
1667 if (from_schedule) {
1668 btrfs_init_work(&plug->work, unplug_work, NULL, NULL);
1669 btrfs_queue_work(plug->info->rmw_workers,
1670 &plug->work);
1671 return;
1672 }
1673 run_plug(plug);
1674}
1675
1676/*
1677 * our main entry point for writes from the rest of the FS.
1678 */
1679int raid56_parity_write(struct btrfs_root *root, struct bio *bio,
1680 struct btrfs_bio *bbio, u64 *raid_map,
1681 u64 stripe_len)
1682{
1683 struct btrfs_raid_bio *rbio;
1684 struct btrfs_plug_cb *plug = NULL;
1685 struct blk_plug_cb *cb;
1686
1687 rbio = alloc_rbio(root, bbio, raid_map, stripe_len);
1688 if (IS_ERR(rbio))
1689 return PTR_ERR(rbio);
1690 bio_list_add(&rbio->bio_list, bio);
1691 rbio->bio_list_bytes = bio->bi_iter.bi_size;
1692
1693 /*
1694 * don't plug on full rbios, just get them out the door
1695 * as quickly as we can
1696 */
1697 if (rbio_is_full(rbio))
1698 return full_stripe_write(rbio);
1699
1700 cb = blk_check_plugged(btrfs_raid_unplug, root->fs_info,
1701 sizeof(*plug));
1702 if (cb) {
1703 plug = container_of(cb, struct btrfs_plug_cb, cb);
1704 if (!plug->info) {
1705 plug->info = root->fs_info;
1706 INIT_LIST_HEAD(&plug->rbio_list);
1707 }
1708 list_add_tail(&rbio->plug_list, &plug->rbio_list);
1709 } else {
1710 return __raid56_parity_write(rbio);
1711 }
1712 return 0;
1713}
1714
1715/*
1716 * all parity reconstruction happens here. We've read in everything
1717 * we can find from the drives and this does the heavy lifting of
1718 * sorting the good from the bad.
1719 */
1720static void __raid_recover_end_io(struct btrfs_raid_bio *rbio)
1721{
1722 int pagenr, stripe;
1723 void **pointers;
1724 int faila = -1, failb = -1;
1725 int nr_pages = (rbio->stripe_len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1726 struct page *page;
1727 int err;
1728 int i;
1729
1730 pointers = kzalloc(rbio->bbio->num_stripes * sizeof(void *),
1731 GFP_NOFS);
1732 if (!pointers) {
1733 err = -ENOMEM;
1734 goto cleanup_io;
1735 }
1736
1737 faila = rbio->faila;
1738 failb = rbio->failb;
1739
1740 if (rbio->read_rebuild) {
1741 spin_lock_irq(&rbio->bio_list_lock);
1742 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1743 spin_unlock_irq(&rbio->bio_list_lock);
1744 }
1745
1746 index_rbio_pages(rbio);
1747
1748 for (pagenr = 0; pagenr < nr_pages; pagenr++) {
1749 /* setup our array of pointers with pages
1750 * from each stripe
1751 */
1752 for (stripe = 0; stripe < rbio->bbio->num_stripes; stripe++) {
1753 /*
1754 * if we're rebuilding a read, we have to use
1755 * pages from the bio list
1756 */
1757 if (rbio->read_rebuild &&
1758 (stripe == faila || stripe == failb)) {
1759 page = page_in_rbio(rbio, stripe, pagenr, 0);
1760 } else {
1761 page = rbio_stripe_page(rbio, stripe, pagenr);
1762 }
1763 pointers[stripe] = kmap(page);
1764 }
1765
1766 /* all raid6 handling here */
1767 if (rbio->raid_map[rbio->bbio->num_stripes - 1] ==
1768 RAID6_Q_STRIPE) {
1769
1770 /*
1771 * single failure, rebuild from parity raid5
1772 * style
1773 */
1774 if (failb < 0) {
1775 if (faila == rbio->nr_data) {
1776 /*
1777 * Just the P stripe has failed, without
1778 * a bad data or Q stripe.
1779 * TODO, we should redo the xor here.
1780 */
1781 err = -EIO;
1782 goto cleanup;
1783 }
1784 /*
1785 * a single failure in raid6 is rebuilt
1786 * in the pstripe code below
1787 */
1788 goto pstripe;
1789 }
1790
1791 /* make sure our ps and qs are in order */
1792 if (faila > failb) {
1793 int tmp = failb;
1794 failb = faila;
1795 faila = tmp;
1796 }
1797
1798 /* if the q stripe is failed, do a pstripe reconstruction
1799 * from the xors.
1800 * If both the q stripe and the P stripe are failed, we're
1801 * here due to a crc mismatch and we can't give them the
1802 * data they want
1803 */
1804 if (rbio->raid_map[failb] == RAID6_Q_STRIPE) {
1805 if (rbio->raid_map[faila] == RAID5_P_STRIPE) {
1806 err = -EIO;
1807 goto cleanup;
1808 }
1809 /*
1810 * otherwise we have one bad data stripe and
1811 * a good P stripe. raid5!
1812 */
1813 goto pstripe;
1814 }
1815
1816 if (rbio->raid_map[failb] == RAID5_P_STRIPE) {
1817 raid6_datap_recov(rbio->bbio->num_stripes,
1818 PAGE_SIZE, faila, pointers);
1819 } else {
1820 raid6_2data_recov(rbio->bbio->num_stripes,
1821 PAGE_SIZE, faila, failb,
1822 pointers);
1823 }
1824 } else {
1825 void *p;
1826
1827 /* rebuild from P stripe here (raid5 or raid6) */
1828 BUG_ON(failb != -1);
1829pstripe:
1830 /* Copy parity block into failed block to start with */
1831 memcpy(pointers[faila],
1832 pointers[rbio->nr_data],
1833 PAGE_CACHE_SIZE);
1834
1835 /* rearrange the pointer array */
1836 p = pointers[faila];
1837 for (stripe = faila; stripe < rbio->nr_data - 1; stripe++)
1838 pointers[stripe] = pointers[stripe + 1];
1839 pointers[rbio->nr_data - 1] = p;
1840
1841 /* xor in the rest */
1842 run_xor(pointers, rbio->nr_data - 1, PAGE_CACHE_SIZE);
1843 }
1844 /* if we're doing this rebuild as part of an rmw, go through
1845 * and set all of our private rbio pages in the
1846 * failed stripes as uptodate. This way finish_rmw will
1847 * know they can be trusted. If this was a read reconstruction,
1848 * other endio functions will fiddle the uptodate bits
1849 */
1850 if (!rbio->read_rebuild) {
1851 for (i = 0; i < nr_pages; i++) {
1852 if (faila != -1) {
1853 page = rbio_stripe_page(rbio, faila, i);
1854 SetPageUptodate(page);
1855 }
1856 if (failb != -1) {
1857 page = rbio_stripe_page(rbio, failb, i);
1858 SetPageUptodate(page);
1859 }
1860 }
1861 }
1862 for (stripe = 0; stripe < rbio->bbio->num_stripes; stripe++) {
1863 /*
1864 * if we're rebuilding a read, we have to use
1865 * pages from the bio list
1866 */
1867 if (rbio->read_rebuild &&
1868 (stripe == faila || stripe == failb)) {
1869 page = page_in_rbio(rbio, stripe, pagenr, 0);
1870 } else {
1871 page = rbio_stripe_page(rbio, stripe, pagenr);
1872 }
1873 kunmap(page);
1874 }
1875 }
1876
1877 err = 0;
1878cleanup:
1879 kfree(pointers);
1880
1881cleanup_io:
1882
1883 if (rbio->read_rebuild) {
1884 if (err == 0)
1885 cache_rbio_pages(rbio);
1886 else
1887 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
1888
1889 rbio_orig_end_io(rbio, err, err == 0);
1890 } else if (err == 0) {
1891 rbio->faila = -1;
1892 rbio->failb = -1;
1893 finish_rmw(rbio);
1894 } else {
1895 rbio_orig_end_io(rbio, err, 0);
1896 }
1897}
1898
1899/*
1900 * This is called only for stripes we've read from disk to
1901 * reconstruct the parity.
1902 */
1903static void raid_recover_end_io(struct bio *bio, int err)
1904{
1905 struct btrfs_raid_bio *rbio = bio->bi_private;
1906
1907 /*
1908 * we only read stripe pages off the disk, set them
1909 * up to date if there were no errors
1910 */
1911 if (err)
1912 fail_bio_stripe(rbio, bio);
1913 else
1914 set_bio_pages_uptodate(bio);
1915 bio_put(bio);
1916
1917 if (!atomic_dec_and_test(&rbio->bbio->stripes_pending))
1918 return;
1919
1920 if (atomic_read(&rbio->bbio->error) > rbio->bbio->max_errors)
1921 rbio_orig_end_io(rbio, -EIO, 0);
1922 else
1923 __raid_recover_end_io(rbio);
1924}
1925
1926/*
1927 * reads everything we need off the disk to reconstruct
1928 * the parity. endio handlers trigger final reconstruction
1929 * when the IO is done.
1930 *
1931 * This is used both for reads from the higher layers and for
1932 * parity construction required to finish a rmw cycle.
1933 */
1934static int __raid56_parity_recover(struct btrfs_raid_bio *rbio)
1935{
1936 int bios_to_read = 0;
1937 struct btrfs_bio *bbio = rbio->bbio;
1938 struct bio_list bio_list;
1939 int ret;
1940 int nr_pages = (rbio->stripe_len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1941 int pagenr;
1942 int stripe;
1943 struct bio *bio;
1944
1945 bio_list_init(&bio_list);
1946
1947 ret = alloc_rbio_pages(rbio);
1948 if (ret)
1949 goto cleanup;
1950
1951 atomic_set(&rbio->bbio->error, 0);
1952
1953 /*
1954 * read everything that hasn't failed. Thanks to the
1955 * stripe cache, it is possible that some or all of these
1956 * pages are going to be uptodate.
1957 */
1958 for (stripe = 0; stripe < bbio->num_stripes; stripe++) {
1959 if (rbio->faila == stripe ||
1960 rbio->failb == stripe)
1961 continue;
1962
1963 for (pagenr = 0; pagenr < nr_pages; pagenr++) {
1964 struct page *p;
1965
1966 /*
1967 * the rmw code may have already read this
1968 * page in
1969 */
1970 p = rbio_stripe_page(rbio, stripe, pagenr);
1971 if (PageUptodate(p))
1972 continue;
1973
1974 ret = rbio_add_io_page(rbio, &bio_list,
1975 rbio_stripe_page(rbio, stripe, pagenr),
1976 stripe, pagenr, rbio->stripe_len);
1977 if (ret < 0)
1978 goto cleanup;
1979 }
1980 }
1981
1982 bios_to_read = bio_list_size(&bio_list);
1983 if (!bios_to_read) {
1984 /*
1985 * we might have no bios to read just because the pages
1986 * were up to date, or we might have no bios to read because
1987 * the devices were gone.
1988 */
1989 if (atomic_read(&rbio->bbio->error) <= rbio->bbio->max_errors) {
1990 __raid_recover_end_io(rbio);
1991 goto out;
1992 } else {
1993 goto cleanup;
1994 }
1995 }
1996
1997 /*
1998 * the bbio may be freed once we submit the last bio. Make sure
1999 * not to touch it after that
2000 */
2001 atomic_set(&bbio->stripes_pending, bios_to_read);
2002 while (1) {
2003 bio = bio_list_pop(&bio_list);
2004 if (!bio)
2005 break;
2006
2007 bio->bi_private = rbio;
2008 bio->bi_end_io = raid_recover_end_io;
2009
2010 btrfs_bio_wq_end_io(rbio->fs_info, bio,
2011 BTRFS_WQ_ENDIO_RAID56);
2012
2013 BUG_ON(!test_bit(BIO_UPTODATE, &bio->bi_flags));
2014 submit_bio(READ, bio);
2015 }
2016out:
2017 return 0;
2018
2019cleanup:
2020 if (rbio->read_rebuild)
2021 rbio_orig_end_io(rbio, -EIO, 0);
2022 return -EIO;
2023}
2024
2025/*
2026 * the main entry point for reads from the higher layers. This
2027 * is really only called when the normal read path had a failure,
2028 * so we assume the bio they send down corresponds to a failed part
2029 * of the drive.
2030 */
2031int raid56_parity_recover(struct btrfs_root *root, struct bio *bio,
2032 struct btrfs_bio *bbio, u64 *raid_map,
2033 u64 stripe_len, int mirror_num)
2034{
2035 struct btrfs_raid_bio *rbio;
2036 int ret;
2037
2038 rbio = alloc_rbio(root, bbio, raid_map, stripe_len);
2039 if (IS_ERR(rbio))
2040 return PTR_ERR(rbio);
2041
2042 rbio->read_rebuild = 1;
2043 bio_list_add(&rbio->bio_list, bio);
2044 rbio->bio_list_bytes = bio->bi_iter.bi_size;
2045
2046 rbio->faila = find_logical_bio_stripe(rbio, bio);
2047 if (rbio->faila == -1) {
2048 BUG();
2049 kfree(raid_map);
2050 kfree(bbio);
2051 kfree(rbio);
2052 return -EIO;
2053 }
2054
2055 /*
2056 * reconstruct from the q stripe if they are
2057 * asking for mirror 3
2058 */
2059 if (mirror_num == 3)
2060 rbio->failb = bbio->num_stripes - 2;
2061
2062 ret = lock_stripe_add(rbio);
2063
2064 /*
2065 * __raid56_parity_recover will end the bio with
2066 * any errors it hits. We don't want to return
2067 * its error value up the stack because our caller
2068 * will end up calling bio_endio with any nonzero
2069 * return
2070 */
2071 if (ret == 0)
2072 __raid56_parity_recover(rbio);
2073 /*
2074 * our rbio has been added to the list of
2075 * rbios that will be handled after the
2076 * currently lock owner is done
2077 */
2078 return 0;
2079
2080}
2081
2082static void rmw_work(struct btrfs_work *work)
2083{
2084 struct btrfs_raid_bio *rbio;
2085
2086 rbio = container_of(work, struct btrfs_raid_bio, work);
2087 raid56_rmw_stripe(rbio);
2088}
2089
2090static void read_rebuild_work(struct btrfs_work *work)
2091{
2092 struct btrfs_raid_bio *rbio;
2093
2094 rbio = container_of(work, struct btrfs_raid_bio, work);
2095 __raid56_parity_recover(rbio);
2096}