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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2012 Fusion-io All rights reserved.
4 * Copyright (C) 2012 Intel Corp. All rights reserved.
5 */
6
7#include <linux/sched.h>
8#include <linux/bio.h>
9#include <linux/slab.h>
10#include <linux/blkdev.h>
11#include <linux/raid/pq.h>
12#include <linux/hash.h>
13#include <linux/list_sort.h>
14#include <linux/raid/xor.h>
15#include <linux/mm.h>
16#include "messages.h"
17#include "ctree.h"
18#include "disk-io.h"
19#include "volumes.h"
20#include "raid56.h"
21#include "async-thread.h"
22#include "file-item.h"
23#include "btrfs_inode.h"
24
25/* set when additional merges to this rbio are not allowed */
26#define RBIO_RMW_LOCKED_BIT 1
27
28/*
29 * set when this rbio is sitting in the hash, but it is just a cache
30 * of past RMW
31 */
32#define RBIO_CACHE_BIT 2
33
34/*
35 * set when it is safe to trust the stripe_pages for caching
36 */
37#define RBIO_CACHE_READY_BIT 3
38
39#define RBIO_CACHE_SIZE 1024
40
41#define BTRFS_STRIPE_HASH_TABLE_BITS 11
42
43static void dump_bioc(const struct btrfs_fs_info *fs_info, const struct btrfs_io_context *bioc)
44{
45 if (unlikely(!bioc)) {
46 btrfs_crit(fs_info, "bioc=NULL");
47 return;
48 }
49 btrfs_crit(fs_info,
50"bioc logical=%llu full_stripe=%llu size=%llu map_type=0x%llx mirror=%u replace_nr_stripes=%u replace_stripe_src=%d num_stripes=%u",
51 bioc->logical, bioc->full_stripe_logical, bioc->size,
52 bioc->map_type, bioc->mirror_num, bioc->replace_nr_stripes,
53 bioc->replace_stripe_src, bioc->num_stripes);
54 for (int i = 0; i < bioc->num_stripes; i++) {
55 btrfs_crit(fs_info, " nr=%d devid=%llu physical=%llu",
56 i, bioc->stripes[i].dev->devid,
57 bioc->stripes[i].physical);
58 }
59}
60
61static void btrfs_dump_rbio(const struct btrfs_fs_info *fs_info,
62 const struct btrfs_raid_bio *rbio)
63{
64 if (!IS_ENABLED(CONFIG_BTRFS_ASSERT))
65 return;
66
67 dump_bioc(fs_info, rbio->bioc);
68 btrfs_crit(fs_info,
69"rbio flags=0x%lx nr_sectors=%u nr_data=%u real_stripes=%u stripe_nsectors=%u scrubp=%u dbitmap=0x%lx",
70 rbio->flags, rbio->nr_sectors, rbio->nr_data,
71 rbio->real_stripes, rbio->stripe_nsectors,
72 rbio->scrubp, rbio->dbitmap);
73}
74
75#define ASSERT_RBIO(expr, rbio) \
76({ \
77 if (IS_ENABLED(CONFIG_BTRFS_ASSERT) && unlikely(!(expr))) { \
78 const struct btrfs_fs_info *__fs_info = (rbio)->bioc ? \
79 (rbio)->bioc->fs_info : NULL; \
80 \
81 btrfs_dump_rbio(__fs_info, (rbio)); \
82 } \
83 ASSERT((expr)); \
84})
85
86#define ASSERT_RBIO_STRIPE(expr, rbio, stripe_nr) \
87({ \
88 if (IS_ENABLED(CONFIG_BTRFS_ASSERT) && unlikely(!(expr))) { \
89 const struct btrfs_fs_info *__fs_info = (rbio)->bioc ? \
90 (rbio)->bioc->fs_info : NULL; \
91 \
92 btrfs_dump_rbio(__fs_info, (rbio)); \
93 btrfs_crit(__fs_info, "stripe_nr=%d", (stripe_nr)); \
94 } \
95 ASSERT((expr)); \
96})
97
98#define ASSERT_RBIO_SECTOR(expr, rbio, sector_nr) \
99({ \
100 if (IS_ENABLED(CONFIG_BTRFS_ASSERT) && unlikely(!(expr))) { \
101 const struct btrfs_fs_info *__fs_info = (rbio)->bioc ? \
102 (rbio)->bioc->fs_info : NULL; \
103 \
104 btrfs_dump_rbio(__fs_info, (rbio)); \
105 btrfs_crit(__fs_info, "sector_nr=%d", (sector_nr)); \
106 } \
107 ASSERT((expr)); \
108})
109
110#define ASSERT_RBIO_LOGICAL(expr, rbio, logical) \
111({ \
112 if (IS_ENABLED(CONFIG_BTRFS_ASSERT) && unlikely(!(expr))) { \
113 const struct btrfs_fs_info *__fs_info = (rbio)->bioc ? \
114 (rbio)->bioc->fs_info : NULL; \
115 \
116 btrfs_dump_rbio(__fs_info, (rbio)); \
117 btrfs_crit(__fs_info, "logical=%llu", (logical)); \
118 } \
119 ASSERT((expr)); \
120})
121
122/* Used by the raid56 code to lock stripes for read/modify/write */
123struct btrfs_stripe_hash {
124 struct list_head hash_list;
125 spinlock_t lock;
126};
127
128/* Used by the raid56 code to lock stripes for read/modify/write */
129struct btrfs_stripe_hash_table {
130 struct list_head stripe_cache;
131 spinlock_t cache_lock;
132 int cache_size;
133 struct btrfs_stripe_hash table[];
134};
135
136/*
137 * A bvec like structure to present a sector inside a page.
138 *
139 * Unlike bvec we don't need bvlen, as it's fixed to sectorsize.
140 */
141struct sector_ptr {
142 struct page *page;
143 unsigned int pgoff:24;
144 unsigned int uptodate:8;
145};
146
147static void rmw_rbio_work(struct work_struct *work);
148static void rmw_rbio_work_locked(struct work_struct *work);
149static void index_rbio_pages(struct btrfs_raid_bio *rbio);
150static int alloc_rbio_pages(struct btrfs_raid_bio *rbio);
151
152static int finish_parity_scrub(struct btrfs_raid_bio *rbio);
153static void scrub_rbio_work_locked(struct work_struct *work);
154
155static void free_raid_bio_pointers(struct btrfs_raid_bio *rbio)
156{
157 bitmap_free(rbio->error_bitmap);
158 kfree(rbio->stripe_pages);
159 kfree(rbio->bio_sectors);
160 kfree(rbio->stripe_sectors);
161 kfree(rbio->finish_pointers);
162}
163
164static void free_raid_bio(struct btrfs_raid_bio *rbio)
165{
166 int i;
167
168 if (!refcount_dec_and_test(&rbio->refs))
169 return;
170
171 WARN_ON(!list_empty(&rbio->stripe_cache));
172 WARN_ON(!list_empty(&rbio->hash_list));
173 WARN_ON(!bio_list_empty(&rbio->bio_list));
174
175 for (i = 0; i < rbio->nr_pages; i++) {
176 if (rbio->stripe_pages[i]) {
177 __free_page(rbio->stripe_pages[i]);
178 rbio->stripe_pages[i] = NULL;
179 }
180 }
181
182 btrfs_put_bioc(rbio->bioc);
183 free_raid_bio_pointers(rbio);
184 kfree(rbio);
185}
186
187static void start_async_work(struct btrfs_raid_bio *rbio, work_func_t work_func)
188{
189 INIT_WORK(&rbio->work, work_func);
190 queue_work(rbio->bioc->fs_info->rmw_workers, &rbio->work);
191}
192
193/*
194 * the stripe hash table is used for locking, and to collect
195 * bios in hopes of making a full stripe
196 */
197int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info)
198{
199 struct btrfs_stripe_hash_table *table;
200 struct btrfs_stripe_hash_table *x;
201 struct btrfs_stripe_hash *cur;
202 struct btrfs_stripe_hash *h;
203 int num_entries = 1 << BTRFS_STRIPE_HASH_TABLE_BITS;
204 int i;
205
206 if (info->stripe_hash_table)
207 return 0;
208
209 /*
210 * The table is large, starting with order 4 and can go as high as
211 * order 7 in case lock debugging is turned on.
212 *
213 * Try harder to allocate and fallback to vmalloc to lower the chance
214 * of a failing mount.
215 */
216 table = kvzalloc(struct_size(table, table, num_entries), GFP_KERNEL);
217 if (!table)
218 return -ENOMEM;
219
220 spin_lock_init(&table->cache_lock);
221 INIT_LIST_HEAD(&table->stripe_cache);
222
223 h = table->table;
224
225 for (i = 0; i < num_entries; i++) {
226 cur = h + i;
227 INIT_LIST_HEAD(&cur->hash_list);
228 spin_lock_init(&cur->lock);
229 }
230
231 x = cmpxchg(&info->stripe_hash_table, NULL, table);
232 kvfree(x);
233 return 0;
234}
235
236/*
237 * caching an rbio means to copy anything from the
238 * bio_sectors array into the stripe_pages array. We
239 * use the page uptodate bit in the stripe cache array
240 * to indicate if it has valid data
241 *
242 * once the caching is done, we set the cache ready
243 * bit.
244 */
245static void cache_rbio_pages(struct btrfs_raid_bio *rbio)
246{
247 int i;
248 int ret;
249
250 ret = alloc_rbio_pages(rbio);
251 if (ret)
252 return;
253
254 for (i = 0; i < rbio->nr_sectors; i++) {
255 /* Some range not covered by bio (partial write), skip it */
256 if (!rbio->bio_sectors[i].page) {
257 /*
258 * Even if the sector is not covered by bio, if it is
259 * a data sector it should still be uptodate as it is
260 * read from disk.
261 */
262 if (i < rbio->nr_data * rbio->stripe_nsectors)
263 ASSERT(rbio->stripe_sectors[i].uptodate);
264 continue;
265 }
266
267 ASSERT(rbio->stripe_sectors[i].page);
268 memcpy_page(rbio->stripe_sectors[i].page,
269 rbio->stripe_sectors[i].pgoff,
270 rbio->bio_sectors[i].page,
271 rbio->bio_sectors[i].pgoff,
272 rbio->bioc->fs_info->sectorsize);
273 rbio->stripe_sectors[i].uptodate = 1;
274 }
275 set_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
276}
277
278/*
279 * we hash on the first logical address of the stripe
280 */
281static int rbio_bucket(struct btrfs_raid_bio *rbio)
282{
283 u64 num = rbio->bioc->full_stripe_logical;
284
285 /*
286 * we shift down quite a bit. We're using byte
287 * addressing, and most of the lower bits are zeros.
288 * This tends to upset hash_64, and it consistently
289 * returns just one or two different values.
290 *
291 * shifting off the lower bits fixes things.
292 */
293 return hash_64(num >> 16, BTRFS_STRIPE_HASH_TABLE_BITS);
294}
295
296static bool full_page_sectors_uptodate(struct btrfs_raid_bio *rbio,
297 unsigned int page_nr)
298{
299 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
300 const u32 sectors_per_page = PAGE_SIZE / sectorsize;
301 int i;
302
303 ASSERT(page_nr < rbio->nr_pages);
304
305 for (i = sectors_per_page * page_nr;
306 i < sectors_per_page * page_nr + sectors_per_page;
307 i++) {
308 if (!rbio->stripe_sectors[i].uptodate)
309 return false;
310 }
311 return true;
312}
313
314/*
315 * Update the stripe_sectors[] array to use correct page and pgoff
316 *
317 * Should be called every time any page pointer in stripes_pages[] got modified.
318 */
319static void index_stripe_sectors(struct btrfs_raid_bio *rbio)
320{
321 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
322 u32 offset;
323 int i;
324
325 for (i = 0, offset = 0; i < rbio->nr_sectors; i++, offset += sectorsize) {
326 int page_index = offset >> PAGE_SHIFT;
327
328 ASSERT(page_index < rbio->nr_pages);
329 rbio->stripe_sectors[i].page = rbio->stripe_pages[page_index];
330 rbio->stripe_sectors[i].pgoff = offset_in_page(offset);
331 }
332}
333
334static void steal_rbio_page(struct btrfs_raid_bio *src,
335 struct btrfs_raid_bio *dest, int page_nr)
336{
337 const u32 sectorsize = src->bioc->fs_info->sectorsize;
338 const u32 sectors_per_page = PAGE_SIZE / sectorsize;
339 int i;
340
341 if (dest->stripe_pages[page_nr])
342 __free_page(dest->stripe_pages[page_nr]);
343 dest->stripe_pages[page_nr] = src->stripe_pages[page_nr];
344 src->stripe_pages[page_nr] = NULL;
345
346 /* Also update the sector->uptodate bits. */
347 for (i = sectors_per_page * page_nr;
348 i < sectors_per_page * page_nr + sectors_per_page; i++)
349 dest->stripe_sectors[i].uptodate = true;
350}
351
352static bool is_data_stripe_page(struct btrfs_raid_bio *rbio, int page_nr)
353{
354 const int sector_nr = (page_nr << PAGE_SHIFT) >>
355 rbio->bioc->fs_info->sectorsize_bits;
356
357 /*
358 * We have ensured PAGE_SIZE is aligned with sectorsize, thus
359 * we won't have a page which is half data half parity.
360 *
361 * Thus if the first sector of the page belongs to data stripes, then
362 * the full page belongs to data stripes.
363 */
364 return (sector_nr < rbio->nr_data * rbio->stripe_nsectors);
365}
366
367/*
368 * Stealing an rbio means taking all the uptodate pages from the stripe array
369 * in the source rbio and putting them into the destination rbio.
370 *
371 * This will also update the involved stripe_sectors[] which are referring to
372 * the old pages.
373 */
374static void steal_rbio(struct btrfs_raid_bio *src, struct btrfs_raid_bio *dest)
375{
376 int i;
377
378 if (!test_bit(RBIO_CACHE_READY_BIT, &src->flags))
379 return;
380
381 for (i = 0; i < dest->nr_pages; i++) {
382 struct page *p = src->stripe_pages[i];
383
384 /*
385 * We don't need to steal P/Q pages as they will always be
386 * regenerated for RMW or full write anyway.
387 */
388 if (!is_data_stripe_page(src, i))
389 continue;
390
391 /*
392 * If @src already has RBIO_CACHE_READY_BIT, it should have
393 * all data stripe pages present and uptodate.
394 */
395 ASSERT(p);
396 ASSERT(full_page_sectors_uptodate(src, i));
397 steal_rbio_page(src, dest, i);
398 }
399 index_stripe_sectors(dest);
400 index_stripe_sectors(src);
401}
402
403/*
404 * merging means we take the bio_list from the victim and
405 * splice it into the destination. The victim should
406 * be discarded afterwards.
407 *
408 * must be called with dest->rbio_list_lock held
409 */
410static void merge_rbio(struct btrfs_raid_bio *dest,
411 struct btrfs_raid_bio *victim)
412{
413 bio_list_merge_init(&dest->bio_list, &victim->bio_list);
414 dest->bio_list_bytes += victim->bio_list_bytes;
415 /* Also inherit the bitmaps from @victim. */
416 bitmap_or(&dest->dbitmap, &victim->dbitmap, &dest->dbitmap,
417 dest->stripe_nsectors);
418}
419
420/*
421 * used to prune items that are in the cache. The caller
422 * must hold the hash table lock.
423 */
424static void __remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
425{
426 int bucket = rbio_bucket(rbio);
427 struct btrfs_stripe_hash_table *table;
428 struct btrfs_stripe_hash *h;
429 int freeit = 0;
430
431 /*
432 * check the bit again under the hash table lock.
433 */
434 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
435 return;
436
437 table = rbio->bioc->fs_info->stripe_hash_table;
438 h = table->table + bucket;
439
440 /* hold the lock for the bucket because we may be
441 * removing it from the hash table
442 */
443 spin_lock(&h->lock);
444
445 /*
446 * hold the lock for the bio list because we need
447 * to make sure the bio list is empty
448 */
449 spin_lock(&rbio->bio_list_lock);
450
451 if (test_and_clear_bit(RBIO_CACHE_BIT, &rbio->flags)) {
452 list_del_init(&rbio->stripe_cache);
453 table->cache_size -= 1;
454 freeit = 1;
455
456 /* if the bio list isn't empty, this rbio is
457 * still involved in an IO. We take it out
458 * of the cache list, and drop the ref that
459 * was held for the list.
460 *
461 * If the bio_list was empty, we also remove
462 * the rbio from the hash_table, and drop
463 * the corresponding ref
464 */
465 if (bio_list_empty(&rbio->bio_list)) {
466 if (!list_empty(&rbio->hash_list)) {
467 list_del_init(&rbio->hash_list);
468 refcount_dec(&rbio->refs);
469 BUG_ON(!list_empty(&rbio->plug_list));
470 }
471 }
472 }
473
474 spin_unlock(&rbio->bio_list_lock);
475 spin_unlock(&h->lock);
476
477 if (freeit)
478 free_raid_bio(rbio);
479}
480
481/*
482 * prune a given rbio from the cache
483 */
484static void remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
485{
486 struct btrfs_stripe_hash_table *table;
487
488 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
489 return;
490
491 table = rbio->bioc->fs_info->stripe_hash_table;
492
493 spin_lock(&table->cache_lock);
494 __remove_rbio_from_cache(rbio);
495 spin_unlock(&table->cache_lock);
496}
497
498/*
499 * remove everything in the cache
500 */
501static void btrfs_clear_rbio_cache(struct btrfs_fs_info *info)
502{
503 struct btrfs_stripe_hash_table *table;
504 struct btrfs_raid_bio *rbio;
505
506 table = info->stripe_hash_table;
507
508 spin_lock(&table->cache_lock);
509 while (!list_empty(&table->stripe_cache)) {
510 rbio = list_entry(table->stripe_cache.next,
511 struct btrfs_raid_bio,
512 stripe_cache);
513 __remove_rbio_from_cache(rbio);
514 }
515 spin_unlock(&table->cache_lock);
516}
517
518/*
519 * remove all cached entries and free the hash table
520 * used by unmount
521 */
522void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info)
523{
524 if (!info->stripe_hash_table)
525 return;
526 btrfs_clear_rbio_cache(info);
527 kvfree(info->stripe_hash_table);
528 info->stripe_hash_table = NULL;
529}
530
531/*
532 * insert an rbio into the stripe cache. It
533 * must have already been prepared by calling
534 * cache_rbio_pages
535 *
536 * If this rbio was already cached, it gets
537 * moved to the front of the lru.
538 *
539 * If the size of the rbio cache is too big, we
540 * prune an item.
541 */
542static void cache_rbio(struct btrfs_raid_bio *rbio)
543{
544 struct btrfs_stripe_hash_table *table;
545
546 if (!test_bit(RBIO_CACHE_READY_BIT, &rbio->flags))
547 return;
548
549 table = rbio->bioc->fs_info->stripe_hash_table;
550
551 spin_lock(&table->cache_lock);
552 spin_lock(&rbio->bio_list_lock);
553
554 /* bump our ref if we were not in the list before */
555 if (!test_and_set_bit(RBIO_CACHE_BIT, &rbio->flags))
556 refcount_inc(&rbio->refs);
557
558 if (!list_empty(&rbio->stripe_cache)){
559 list_move(&rbio->stripe_cache, &table->stripe_cache);
560 } else {
561 list_add(&rbio->stripe_cache, &table->stripe_cache);
562 table->cache_size += 1;
563 }
564
565 spin_unlock(&rbio->bio_list_lock);
566
567 if (table->cache_size > RBIO_CACHE_SIZE) {
568 struct btrfs_raid_bio *found;
569
570 found = list_entry(table->stripe_cache.prev,
571 struct btrfs_raid_bio,
572 stripe_cache);
573
574 if (found != rbio)
575 __remove_rbio_from_cache(found);
576 }
577
578 spin_unlock(&table->cache_lock);
579}
580
581/*
582 * helper function to run the xor_blocks api. It is only
583 * able to do MAX_XOR_BLOCKS at a time, so we need to
584 * loop through.
585 */
586static void run_xor(void **pages, int src_cnt, ssize_t len)
587{
588 int src_off = 0;
589 int xor_src_cnt = 0;
590 void *dest = pages[src_cnt];
591
592 while(src_cnt > 0) {
593 xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS);
594 xor_blocks(xor_src_cnt, len, dest, pages + src_off);
595
596 src_cnt -= xor_src_cnt;
597 src_off += xor_src_cnt;
598 }
599}
600
601/*
602 * Returns true if the bio list inside this rbio covers an entire stripe (no
603 * rmw required).
604 */
605static int rbio_is_full(struct btrfs_raid_bio *rbio)
606{
607 unsigned long size = rbio->bio_list_bytes;
608 int ret = 1;
609
610 spin_lock(&rbio->bio_list_lock);
611 if (size != rbio->nr_data * BTRFS_STRIPE_LEN)
612 ret = 0;
613 BUG_ON(size > rbio->nr_data * BTRFS_STRIPE_LEN);
614 spin_unlock(&rbio->bio_list_lock);
615
616 return ret;
617}
618
619/*
620 * returns 1 if it is safe to merge two rbios together.
621 * The merging is safe if the two rbios correspond to
622 * the same stripe and if they are both going in the same
623 * direction (read vs write), and if neither one is
624 * locked for final IO
625 *
626 * The caller is responsible for locking such that
627 * rmw_locked is safe to test
628 */
629static int rbio_can_merge(struct btrfs_raid_bio *last,
630 struct btrfs_raid_bio *cur)
631{
632 if (test_bit(RBIO_RMW_LOCKED_BIT, &last->flags) ||
633 test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags))
634 return 0;
635
636 /*
637 * we can't merge with cached rbios, since the
638 * idea is that when we merge the destination
639 * rbio is going to run our IO for us. We can
640 * steal from cached rbios though, other functions
641 * handle that.
642 */
643 if (test_bit(RBIO_CACHE_BIT, &last->flags) ||
644 test_bit(RBIO_CACHE_BIT, &cur->flags))
645 return 0;
646
647 if (last->bioc->full_stripe_logical != cur->bioc->full_stripe_logical)
648 return 0;
649
650 /* we can't merge with different operations */
651 if (last->operation != cur->operation)
652 return 0;
653 /*
654 * We've need read the full stripe from the drive.
655 * check and repair the parity and write the new results.
656 *
657 * We're not allowed to add any new bios to the
658 * bio list here, anyone else that wants to
659 * change this stripe needs to do their own rmw.
660 */
661 if (last->operation == BTRFS_RBIO_PARITY_SCRUB)
662 return 0;
663
664 if (last->operation == BTRFS_RBIO_READ_REBUILD)
665 return 0;
666
667 return 1;
668}
669
670static unsigned int rbio_stripe_sector_index(const struct btrfs_raid_bio *rbio,
671 unsigned int stripe_nr,
672 unsigned int sector_nr)
673{
674 ASSERT_RBIO_STRIPE(stripe_nr < rbio->real_stripes, rbio, stripe_nr);
675 ASSERT_RBIO_SECTOR(sector_nr < rbio->stripe_nsectors, rbio, sector_nr);
676
677 return stripe_nr * rbio->stripe_nsectors + sector_nr;
678}
679
680/* Return a sector from rbio->stripe_sectors, not from the bio list */
681static struct sector_ptr *rbio_stripe_sector(const struct btrfs_raid_bio *rbio,
682 unsigned int stripe_nr,
683 unsigned int sector_nr)
684{
685 return &rbio->stripe_sectors[rbio_stripe_sector_index(rbio, stripe_nr,
686 sector_nr)];
687}
688
689/* Grab a sector inside P stripe */
690static struct sector_ptr *rbio_pstripe_sector(const struct btrfs_raid_bio *rbio,
691 unsigned int sector_nr)
692{
693 return rbio_stripe_sector(rbio, rbio->nr_data, sector_nr);
694}
695
696/* Grab a sector inside Q stripe, return NULL if not RAID6 */
697static struct sector_ptr *rbio_qstripe_sector(const struct btrfs_raid_bio *rbio,
698 unsigned int sector_nr)
699{
700 if (rbio->nr_data + 1 == rbio->real_stripes)
701 return NULL;
702 return rbio_stripe_sector(rbio, rbio->nr_data + 1, sector_nr);
703}
704
705/*
706 * The first stripe in the table for a logical address
707 * has the lock. rbios are added in one of three ways:
708 *
709 * 1) Nobody has the stripe locked yet. The rbio is given
710 * the lock and 0 is returned. The caller must start the IO
711 * themselves.
712 *
713 * 2) Someone has the stripe locked, but we're able to merge
714 * with the lock owner. The rbio is freed and the IO will
715 * start automatically along with the existing rbio. 1 is returned.
716 *
717 * 3) Someone has the stripe locked, but we're not able to merge.
718 * The rbio is added to the lock owner's plug list, or merged into
719 * an rbio already on the plug list. When the lock owner unlocks,
720 * the next rbio on the list is run and the IO is started automatically.
721 * 1 is returned
722 *
723 * If we return 0, the caller still owns the rbio and must continue with
724 * IO submission. If we return 1, the caller must assume the rbio has
725 * already been freed.
726 */
727static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
728{
729 struct btrfs_stripe_hash *h;
730 struct btrfs_raid_bio *cur;
731 struct btrfs_raid_bio *pending;
732 struct btrfs_raid_bio *freeit = NULL;
733 struct btrfs_raid_bio *cache_drop = NULL;
734 int ret = 0;
735
736 h = rbio->bioc->fs_info->stripe_hash_table->table + rbio_bucket(rbio);
737
738 spin_lock(&h->lock);
739 list_for_each_entry(cur, &h->hash_list, hash_list) {
740 if (cur->bioc->full_stripe_logical != rbio->bioc->full_stripe_logical)
741 continue;
742
743 spin_lock(&cur->bio_list_lock);
744
745 /* Can we steal this cached rbio's pages? */
746 if (bio_list_empty(&cur->bio_list) &&
747 list_empty(&cur->plug_list) &&
748 test_bit(RBIO_CACHE_BIT, &cur->flags) &&
749 !test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) {
750 list_del_init(&cur->hash_list);
751 refcount_dec(&cur->refs);
752
753 steal_rbio(cur, rbio);
754 cache_drop = cur;
755 spin_unlock(&cur->bio_list_lock);
756
757 goto lockit;
758 }
759
760 /* Can we merge into the lock owner? */
761 if (rbio_can_merge(cur, rbio)) {
762 merge_rbio(cur, rbio);
763 spin_unlock(&cur->bio_list_lock);
764 freeit = rbio;
765 ret = 1;
766 goto out;
767 }
768
769
770 /*
771 * We couldn't merge with the running rbio, see if we can merge
772 * with the pending ones. We don't have to check for rmw_locked
773 * because there is no way they are inside finish_rmw right now
774 */
775 list_for_each_entry(pending, &cur->plug_list, plug_list) {
776 if (rbio_can_merge(pending, rbio)) {
777 merge_rbio(pending, rbio);
778 spin_unlock(&cur->bio_list_lock);
779 freeit = rbio;
780 ret = 1;
781 goto out;
782 }
783 }
784
785 /*
786 * No merging, put us on the tail of the plug list, our rbio
787 * will be started with the currently running rbio unlocks
788 */
789 list_add_tail(&rbio->plug_list, &cur->plug_list);
790 spin_unlock(&cur->bio_list_lock);
791 ret = 1;
792 goto out;
793 }
794lockit:
795 refcount_inc(&rbio->refs);
796 list_add(&rbio->hash_list, &h->hash_list);
797out:
798 spin_unlock(&h->lock);
799 if (cache_drop)
800 remove_rbio_from_cache(cache_drop);
801 if (freeit)
802 free_raid_bio(freeit);
803 return ret;
804}
805
806static void recover_rbio_work_locked(struct work_struct *work);
807
808/*
809 * called as rmw or parity rebuild is completed. If the plug list has more
810 * rbios waiting for this stripe, the next one on the list will be started
811 */
812static noinline void unlock_stripe(struct btrfs_raid_bio *rbio)
813{
814 int bucket;
815 struct btrfs_stripe_hash *h;
816 int keep_cache = 0;
817
818 bucket = rbio_bucket(rbio);
819 h = rbio->bioc->fs_info->stripe_hash_table->table + bucket;
820
821 if (list_empty(&rbio->plug_list))
822 cache_rbio(rbio);
823
824 spin_lock(&h->lock);
825 spin_lock(&rbio->bio_list_lock);
826
827 if (!list_empty(&rbio->hash_list)) {
828 /*
829 * if we're still cached and there is no other IO
830 * to perform, just leave this rbio here for others
831 * to steal from later
832 */
833 if (list_empty(&rbio->plug_list) &&
834 test_bit(RBIO_CACHE_BIT, &rbio->flags)) {
835 keep_cache = 1;
836 clear_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
837 BUG_ON(!bio_list_empty(&rbio->bio_list));
838 goto done;
839 }
840
841 list_del_init(&rbio->hash_list);
842 refcount_dec(&rbio->refs);
843
844 /*
845 * we use the plug list to hold all the rbios
846 * waiting for the chance to lock this stripe.
847 * hand the lock over to one of them.
848 */
849 if (!list_empty(&rbio->plug_list)) {
850 struct btrfs_raid_bio *next;
851 struct list_head *head = rbio->plug_list.next;
852
853 next = list_entry(head, struct btrfs_raid_bio,
854 plug_list);
855
856 list_del_init(&rbio->plug_list);
857
858 list_add(&next->hash_list, &h->hash_list);
859 refcount_inc(&next->refs);
860 spin_unlock(&rbio->bio_list_lock);
861 spin_unlock(&h->lock);
862
863 if (next->operation == BTRFS_RBIO_READ_REBUILD) {
864 start_async_work(next, recover_rbio_work_locked);
865 } else if (next->operation == BTRFS_RBIO_WRITE) {
866 steal_rbio(rbio, next);
867 start_async_work(next, rmw_rbio_work_locked);
868 } else if (next->operation == BTRFS_RBIO_PARITY_SCRUB) {
869 steal_rbio(rbio, next);
870 start_async_work(next, scrub_rbio_work_locked);
871 }
872
873 goto done_nolock;
874 }
875 }
876done:
877 spin_unlock(&rbio->bio_list_lock);
878 spin_unlock(&h->lock);
879
880done_nolock:
881 if (!keep_cache)
882 remove_rbio_from_cache(rbio);
883}
884
885static void rbio_endio_bio_list(struct bio *cur, blk_status_t err)
886{
887 struct bio *next;
888
889 while (cur) {
890 next = cur->bi_next;
891 cur->bi_next = NULL;
892 cur->bi_status = err;
893 bio_endio(cur);
894 cur = next;
895 }
896}
897
898/*
899 * this frees the rbio and runs through all the bios in the
900 * bio_list and calls end_io on them
901 */
902static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, blk_status_t err)
903{
904 struct bio *cur = bio_list_get(&rbio->bio_list);
905 struct bio *extra;
906
907 kfree(rbio->csum_buf);
908 bitmap_free(rbio->csum_bitmap);
909 rbio->csum_buf = NULL;
910 rbio->csum_bitmap = NULL;
911
912 /*
913 * Clear the data bitmap, as the rbio may be cached for later usage.
914 * do this before before unlock_stripe() so there will be no new bio
915 * for this bio.
916 */
917 bitmap_clear(&rbio->dbitmap, 0, rbio->stripe_nsectors);
918
919 /*
920 * At this moment, rbio->bio_list is empty, however since rbio does not
921 * always have RBIO_RMW_LOCKED_BIT set and rbio is still linked on the
922 * hash list, rbio may be merged with others so that rbio->bio_list
923 * becomes non-empty.
924 * Once unlock_stripe() is done, rbio->bio_list will not be updated any
925 * more and we can call bio_endio() on all queued bios.
926 */
927 unlock_stripe(rbio);
928 extra = bio_list_get(&rbio->bio_list);
929 free_raid_bio(rbio);
930
931 rbio_endio_bio_list(cur, err);
932 if (extra)
933 rbio_endio_bio_list(extra, err);
934}
935
936/*
937 * Get a sector pointer specified by its @stripe_nr and @sector_nr.
938 *
939 * @rbio: The raid bio
940 * @stripe_nr: Stripe number, valid range [0, real_stripe)
941 * @sector_nr: Sector number inside the stripe,
942 * valid range [0, stripe_nsectors)
943 * @bio_list_only: Whether to use sectors inside the bio list only.
944 *
945 * The read/modify/write code wants to reuse the original bio page as much
946 * as possible, and only use stripe_sectors as fallback.
947 */
948static struct sector_ptr *sector_in_rbio(struct btrfs_raid_bio *rbio,
949 int stripe_nr, int sector_nr,
950 bool bio_list_only)
951{
952 struct sector_ptr *sector;
953 int index;
954
955 ASSERT_RBIO_STRIPE(stripe_nr >= 0 && stripe_nr < rbio->real_stripes,
956 rbio, stripe_nr);
957 ASSERT_RBIO_SECTOR(sector_nr >= 0 && sector_nr < rbio->stripe_nsectors,
958 rbio, sector_nr);
959
960 index = stripe_nr * rbio->stripe_nsectors + sector_nr;
961 ASSERT(index >= 0 && index < rbio->nr_sectors);
962
963 spin_lock(&rbio->bio_list_lock);
964 sector = &rbio->bio_sectors[index];
965 if (sector->page || bio_list_only) {
966 /* Don't return sector without a valid page pointer */
967 if (!sector->page)
968 sector = NULL;
969 spin_unlock(&rbio->bio_list_lock);
970 return sector;
971 }
972 spin_unlock(&rbio->bio_list_lock);
973
974 return &rbio->stripe_sectors[index];
975}
976
977/*
978 * allocation and initial setup for the btrfs_raid_bio. Not
979 * this does not allocate any pages for rbio->pages.
980 */
981static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info,
982 struct btrfs_io_context *bioc)
983{
984 const unsigned int real_stripes = bioc->num_stripes - bioc->replace_nr_stripes;
985 const unsigned int stripe_npages = BTRFS_STRIPE_LEN >> PAGE_SHIFT;
986 const unsigned int num_pages = stripe_npages * real_stripes;
987 const unsigned int stripe_nsectors =
988 BTRFS_STRIPE_LEN >> fs_info->sectorsize_bits;
989 const unsigned int num_sectors = stripe_nsectors * real_stripes;
990 struct btrfs_raid_bio *rbio;
991
992 /* PAGE_SIZE must also be aligned to sectorsize for subpage support */
993 ASSERT(IS_ALIGNED(PAGE_SIZE, fs_info->sectorsize));
994 /*
995 * Our current stripe len should be fixed to 64k thus stripe_nsectors
996 * (at most 16) should be no larger than BITS_PER_LONG.
997 */
998 ASSERT(stripe_nsectors <= BITS_PER_LONG);
999
1000 /*
1001 * Real stripes must be between 2 (2 disks RAID5, aka RAID1) and 256
1002 * (limited by u8).
1003 */
1004 ASSERT(real_stripes >= 2);
1005 ASSERT(real_stripes <= U8_MAX);
1006
1007 rbio = kzalloc(sizeof(*rbio), GFP_NOFS);
1008 if (!rbio)
1009 return ERR_PTR(-ENOMEM);
1010 rbio->stripe_pages = kcalloc(num_pages, sizeof(struct page *),
1011 GFP_NOFS);
1012 rbio->bio_sectors = kcalloc(num_sectors, sizeof(struct sector_ptr),
1013 GFP_NOFS);
1014 rbio->stripe_sectors = kcalloc(num_sectors, sizeof(struct sector_ptr),
1015 GFP_NOFS);
1016 rbio->finish_pointers = kcalloc(real_stripes, sizeof(void *), GFP_NOFS);
1017 rbio->error_bitmap = bitmap_zalloc(num_sectors, GFP_NOFS);
1018
1019 if (!rbio->stripe_pages || !rbio->bio_sectors || !rbio->stripe_sectors ||
1020 !rbio->finish_pointers || !rbio->error_bitmap) {
1021 free_raid_bio_pointers(rbio);
1022 kfree(rbio);
1023 return ERR_PTR(-ENOMEM);
1024 }
1025
1026 bio_list_init(&rbio->bio_list);
1027 init_waitqueue_head(&rbio->io_wait);
1028 INIT_LIST_HEAD(&rbio->plug_list);
1029 spin_lock_init(&rbio->bio_list_lock);
1030 INIT_LIST_HEAD(&rbio->stripe_cache);
1031 INIT_LIST_HEAD(&rbio->hash_list);
1032 btrfs_get_bioc(bioc);
1033 rbio->bioc = bioc;
1034 rbio->nr_pages = num_pages;
1035 rbio->nr_sectors = num_sectors;
1036 rbio->real_stripes = real_stripes;
1037 rbio->stripe_npages = stripe_npages;
1038 rbio->stripe_nsectors = stripe_nsectors;
1039 refcount_set(&rbio->refs, 1);
1040 atomic_set(&rbio->stripes_pending, 0);
1041
1042 ASSERT(btrfs_nr_parity_stripes(bioc->map_type));
1043 rbio->nr_data = real_stripes - btrfs_nr_parity_stripes(bioc->map_type);
1044 ASSERT(rbio->nr_data > 0);
1045
1046 return rbio;
1047}
1048
1049/* allocate pages for all the stripes in the bio, including parity */
1050static int alloc_rbio_pages(struct btrfs_raid_bio *rbio)
1051{
1052 int ret;
1053
1054 ret = btrfs_alloc_page_array(rbio->nr_pages, rbio->stripe_pages, false);
1055 if (ret < 0)
1056 return ret;
1057 /* Mapping all sectors */
1058 index_stripe_sectors(rbio);
1059 return 0;
1060}
1061
1062/* only allocate pages for p/q stripes */
1063static int alloc_rbio_parity_pages(struct btrfs_raid_bio *rbio)
1064{
1065 const int data_pages = rbio->nr_data * rbio->stripe_npages;
1066 int ret;
1067
1068 ret = btrfs_alloc_page_array(rbio->nr_pages - data_pages,
1069 rbio->stripe_pages + data_pages, false);
1070 if (ret < 0)
1071 return ret;
1072
1073 index_stripe_sectors(rbio);
1074 return 0;
1075}
1076
1077/*
1078 * Return the total number of errors found in the vertical stripe of @sector_nr.
1079 *
1080 * @faila and @failb will also be updated to the first and second stripe
1081 * number of the errors.
1082 */
1083static int get_rbio_veritical_errors(struct btrfs_raid_bio *rbio, int sector_nr,
1084 int *faila, int *failb)
1085{
1086 int stripe_nr;
1087 int found_errors = 0;
1088
1089 if (faila || failb) {
1090 /*
1091 * Both @faila and @failb should be valid pointers if any of
1092 * them is specified.
1093 */
1094 ASSERT(faila && failb);
1095 *faila = -1;
1096 *failb = -1;
1097 }
1098
1099 for (stripe_nr = 0; stripe_nr < rbio->real_stripes; stripe_nr++) {
1100 int total_sector_nr = stripe_nr * rbio->stripe_nsectors + sector_nr;
1101
1102 if (test_bit(total_sector_nr, rbio->error_bitmap)) {
1103 found_errors++;
1104 if (faila) {
1105 /* Update faila and failb. */
1106 if (*faila < 0)
1107 *faila = stripe_nr;
1108 else if (*failb < 0)
1109 *failb = stripe_nr;
1110 }
1111 }
1112 }
1113 return found_errors;
1114}
1115
1116/*
1117 * Add a single sector @sector into our list of bios for IO.
1118 *
1119 * Return 0 if everything went well.
1120 * Return <0 for error.
1121 */
1122static int rbio_add_io_sector(struct btrfs_raid_bio *rbio,
1123 struct bio_list *bio_list,
1124 struct sector_ptr *sector,
1125 unsigned int stripe_nr,
1126 unsigned int sector_nr,
1127 enum req_op op)
1128{
1129 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
1130 struct bio *last = bio_list->tail;
1131 int ret;
1132 struct bio *bio;
1133 struct btrfs_io_stripe *stripe;
1134 u64 disk_start;
1135
1136 /*
1137 * Note: here stripe_nr has taken device replace into consideration,
1138 * thus it can be larger than rbio->real_stripe.
1139 * So here we check against bioc->num_stripes, not rbio->real_stripes.
1140 */
1141 ASSERT_RBIO_STRIPE(stripe_nr >= 0 && stripe_nr < rbio->bioc->num_stripes,
1142 rbio, stripe_nr);
1143 ASSERT_RBIO_SECTOR(sector_nr >= 0 && sector_nr < rbio->stripe_nsectors,
1144 rbio, sector_nr);
1145 ASSERT(sector->page);
1146
1147 stripe = &rbio->bioc->stripes[stripe_nr];
1148 disk_start = stripe->physical + sector_nr * sectorsize;
1149
1150 /* if the device is missing, just fail this stripe */
1151 if (!stripe->dev->bdev) {
1152 int found_errors;
1153
1154 set_bit(stripe_nr * rbio->stripe_nsectors + sector_nr,
1155 rbio->error_bitmap);
1156
1157 /* Check if we have reached tolerance early. */
1158 found_errors = get_rbio_veritical_errors(rbio, sector_nr,
1159 NULL, NULL);
1160 if (found_errors > rbio->bioc->max_errors)
1161 return -EIO;
1162 return 0;
1163 }
1164
1165 /* see if we can add this page onto our existing bio */
1166 if (last) {
1167 u64 last_end = last->bi_iter.bi_sector << SECTOR_SHIFT;
1168 last_end += last->bi_iter.bi_size;
1169
1170 /*
1171 * we can't merge these if they are from different
1172 * devices or if they are not contiguous
1173 */
1174 if (last_end == disk_start && !last->bi_status &&
1175 last->bi_bdev == stripe->dev->bdev) {
1176 ret = bio_add_page(last, sector->page, sectorsize,
1177 sector->pgoff);
1178 if (ret == sectorsize)
1179 return 0;
1180 }
1181 }
1182
1183 /* put a new bio on the list */
1184 bio = bio_alloc(stripe->dev->bdev,
1185 max(BTRFS_STRIPE_LEN >> PAGE_SHIFT, 1),
1186 op, GFP_NOFS);
1187 bio->bi_iter.bi_sector = disk_start >> SECTOR_SHIFT;
1188 bio->bi_private = rbio;
1189
1190 __bio_add_page(bio, sector->page, sectorsize, sector->pgoff);
1191 bio_list_add(bio_list, bio);
1192 return 0;
1193}
1194
1195static void index_one_bio(struct btrfs_raid_bio *rbio, struct bio *bio)
1196{
1197 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
1198 struct bio_vec bvec;
1199 struct bvec_iter iter;
1200 u32 offset = (bio->bi_iter.bi_sector << SECTOR_SHIFT) -
1201 rbio->bioc->full_stripe_logical;
1202
1203 bio_for_each_segment(bvec, bio, iter) {
1204 u32 bvec_offset;
1205
1206 for (bvec_offset = 0; bvec_offset < bvec.bv_len;
1207 bvec_offset += sectorsize, offset += sectorsize) {
1208 int index = offset / sectorsize;
1209 struct sector_ptr *sector = &rbio->bio_sectors[index];
1210
1211 sector->page = bvec.bv_page;
1212 sector->pgoff = bvec.bv_offset + bvec_offset;
1213 ASSERT(sector->pgoff < PAGE_SIZE);
1214 }
1215 }
1216}
1217
1218/*
1219 * helper function to walk our bio list and populate the bio_pages array with
1220 * the result. This seems expensive, but it is faster than constantly
1221 * searching through the bio list as we setup the IO in finish_rmw or stripe
1222 * reconstruction.
1223 *
1224 * This must be called before you trust the answers from page_in_rbio
1225 */
1226static void index_rbio_pages(struct btrfs_raid_bio *rbio)
1227{
1228 struct bio *bio;
1229
1230 spin_lock(&rbio->bio_list_lock);
1231 bio_list_for_each(bio, &rbio->bio_list)
1232 index_one_bio(rbio, bio);
1233
1234 spin_unlock(&rbio->bio_list_lock);
1235}
1236
1237static void bio_get_trace_info(struct btrfs_raid_bio *rbio, struct bio *bio,
1238 struct raid56_bio_trace_info *trace_info)
1239{
1240 const struct btrfs_io_context *bioc = rbio->bioc;
1241 int i;
1242
1243 ASSERT(bioc);
1244
1245 /* We rely on bio->bi_bdev to find the stripe number. */
1246 if (!bio->bi_bdev)
1247 goto not_found;
1248
1249 for (i = 0; i < bioc->num_stripes; i++) {
1250 if (bio->bi_bdev != bioc->stripes[i].dev->bdev)
1251 continue;
1252 trace_info->stripe_nr = i;
1253 trace_info->devid = bioc->stripes[i].dev->devid;
1254 trace_info->offset = (bio->bi_iter.bi_sector << SECTOR_SHIFT) -
1255 bioc->stripes[i].physical;
1256 return;
1257 }
1258
1259not_found:
1260 trace_info->devid = -1;
1261 trace_info->offset = -1;
1262 trace_info->stripe_nr = -1;
1263}
1264
1265static inline void bio_list_put(struct bio_list *bio_list)
1266{
1267 struct bio *bio;
1268
1269 while ((bio = bio_list_pop(bio_list)))
1270 bio_put(bio);
1271}
1272
1273static void assert_rbio(struct btrfs_raid_bio *rbio)
1274{
1275 if (!IS_ENABLED(CONFIG_BTRFS_ASSERT))
1276 return;
1277
1278 /*
1279 * At least two stripes (2 disks RAID5), and since real_stripes is U8,
1280 * we won't go beyond 256 disks anyway.
1281 */
1282 ASSERT_RBIO(rbio->real_stripes >= 2, rbio);
1283 ASSERT_RBIO(rbio->nr_data > 0, rbio);
1284
1285 /*
1286 * This is another check to make sure nr data stripes is smaller
1287 * than total stripes.
1288 */
1289 ASSERT_RBIO(rbio->nr_data < rbio->real_stripes, rbio);
1290}
1291
1292/* Generate PQ for one vertical stripe. */
1293static void generate_pq_vertical(struct btrfs_raid_bio *rbio, int sectornr)
1294{
1295 void **pointers = rbio->finish_pointers;
1296 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
1297 struct sector_ptr *sector;
1298 int stripe;
1299 const bool has_qstripe = rbio->bioc->map_type & BTRFS_BLOCK_GROUP_RAID6;
1300
1301 /* First collect one sector from each data stripe */
1302 for (stripe = 0; stripe < rbio->nr_data; stripe++) {
1303 sector = sector_in_rbio(rbio, stripe, sectornr, 0);
1304 pointers[stripe] = kmap_local_page(sector->page) +
1305 sector->pgoff;
1306 }
1307
1308 /* Then add the parity stripe */
1309 sector = rbio_pstripe_sector(rbio, sectornr);
1310 sector->uptodate = 1;
1311 pointers[stripe++] = kmap_local_page(sector->page) + sector->pgoff;
1312
1313 if (has_qstripe) {
1314 /*
1315 * RAID6, add the qstripe and call the library function
1316 * to fill in our p/q
1317 */
1318 sector = rbio_qstripe_sector(rbio, sectornr);
1319 sector->uptodate = 1;
1320 pointers[stripe++] = kmap_local_page(sector->page) +
1321 sector->pgoff;
1322
1323 assert_rbio(rbio);
1324 raid6_call.gen_syndrome(rbio->real_stripes, sectorsize,
1325 pointers);
1326 } else {
1327 /* raid5 */
1328 memcpy(pointers[rbio->nr_data], pointers[0], sectorsize);
1329 run_xor(pointers + 1, rbio->nr_data - 1, sectorsize);
1330 }
1331 for (stripe = stripe - 1; stripe >= 0; stripe--)
1332 kunmap_local(pointers[stripe]);
1333}
1334
1335static int rmw_assemble_write_bios(struct btrfs_raid_bio *rbio,
1336 struct bio_list *bio_list)
1337{
1338 /* The total sector number inside the full stripe. */
1339 int total_sector_nr;
1340 int sectornr;
1341 int stripe;
1342 int ret;
1343
1344 ASSERT(bio_list_size(bio_list) == 0);
1345
1346 /* We should have at least one data sector. */
1347 ASSERT(bitmap_weight(&rbio->dbitmap, rbio->stripe_nsectors));
1348
1349 /*
1350 * Reset errors, as we may have errors inherited from from degraded
1351 * write.
1352 */
1353 bitmap_clear(rbio->error_bitmap, 0, rbio->nr_sectors);
1354
1355 /*
1356 * Start assembly. Make bios for everything from the higher layers (the
1357 * bio_list in our rbio) and our P/Q. Ignore everything else.
1358 */
1359 for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
1360 total_sector_nr++) {
1361 struct sector_ptr *sector;
1362
1363 stripe = total_sector_nr / rbio->stripe_nsectors;
1364 sectornr = total_sector_nr % rbio->stripe_nsectors;
1365
1366 /* This vertical stripe has no data, skip it. */
1367 if (!test_bit(sectornr, &rbio->dbitmap))
1368 continue;
1369
1370 if (stripe < rbio->nr_data) {
1371 sector = sector_in_rbio(rbio, stripe, sectornr, 1);
1372 if (!sector)
1373 continue;
1374 } else {
1375 sector = rbio_stripe_sector(rbio, stripe, sectornr);
1376 }
1377
1378 ret = rbio_add_io_sector(rbio, bio_list, sector, stripe,
1379 sectornr, REQ_OP_WRITE);
1380 if (ret)
1381 goto error;
1382 }
1383
1384 if (likely(!rbio->bioc->replace_nr_stripes))
1385 return 0;
1386
1387 /*
1388 * Make a copy for the replace target device.
1389 *
1390 * Thus the source stripe number (in replace_stripe_src) should be valid.
1391 */
1392 ASSERT(rbio->bioc->replace_stripe_src >= 0);
1393
1394 for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
1395 total_sector_nr++) {
1396 struct sector_ptr *sector;
1397
1398 stripe = total_sector_nr / rbio->stripe_nsectors;
1399 sectornr = total_sector_nr % rbio->stripe_nsectors;
1400
1401 /*
1402 * For RAID56, there is only one device that can be replaced,
1403 * and replace_stripe_src[0] indicates the stripe number we
1404 * need to copy from.
1405 */
1406 if (stripe != rbio->bioc->replace_stripe_src) {
1407 /*
1408 * We can skip the whole stripe completely, note
1409 * total_sector_nr will be increased by one anyway.
1410 */
1411 ASSERT(sectornr == 0);
1412 total_sector_nr += rbio->stripe_nsectors - 1;
1413 continue;
1414 }
1415
1416 /* This vertical stripe has no data, skip it. */
1417 if (!test_bit(sectornr, &rbio->dbitmap))
1418 continue;
1419
1420 if (stripe < rbio->nr_data) {
1421 sector = sector_in_rbio(rbio, stripe, sectornr, 1);
1422 if (!sector)
1423 continue;
1424 } else {
1425 sector = rbio_stripe_sector(rbio, stripe, sectornr);
1426 }
1427
1428 ret = rbio_add_io_sector(rbio, bio_list, sector,
1429 rbio->real_stripes,
1430 sectornr, REQ_OP_WRITE);
1431 if (ret)
1432 goto error;
1433 }
1434
1435 return 0;
1436error:
1437 bio_list_put(bio_list);
1438 return -EIO;
1439}
1440
1441static void set_rbio_range_error(struct btrfs_raid_bio *rbio, struct bio *bio)
1442{
1443 struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
1444 u32 offset = (bio->bi_iter.bi_sector << SECTOR_SHIFT) -
1445 rbio->bioc->full_stripe_logical;
1446 int total_nr_sector = offset >> fs_info->sectorsize_bits;
1447
1448 ASSERT(total_nr_sector < rbio->nr_data * rbio->stripe_nsectors);
1449
1450 bitmap_set(rbio->error_bitmap, total_nr_sector,
1451 bio->bi_iter.bi_size >> fs_info->sectorsize_bits);
1452
1453 /*
1454 * Special handling for raid56_alloc_missing_rbio() used by
1455 * scrub/replace. Unlike call path in raid56_parity_recover(), they
1456 * pass an empty bio here. Thus we have to find out the missing device
1457 * and mark the stripe error instead.
1458 */
1459 if (bio->bi_iter.bi_size == 0) {
1460 bool found_missing = false;
1461 int stripe_nr;
1462
1463 for (stripe_nr = 0; stripe_nr < rbio->real_stripes; stripe_nr++) {
1464 if (!rbio->bioc->stripes[stripe_nr].dev->bdev) {
1465 found_missing = true;
1466 bitmap_set(rbio->error_bitmap,
1467 stripe_nr * rbio->stripe_nsectors,
1468 rbio->stripe_nsectors);
1469 }
1470 }
1471 ASSERT(found_missing);
1472 }
1473}
1474
1475/*
1476 * For subpage case, we can no longer set page Up-to-date directly for
1477 * stripe_pages[], thus we need to locate the sector.
1478 */
1479static struct sector_ptr *find_stripe_sector(struct btrfs_raid_bio *rbio,
1480 struct page *page,
1481 unsigned int pgoff)
1482{
1483 int i;
1484
1485 for (i = 0; i < rbio->nr_sectors; i++) {
1486 struct sector_ptr *sector = &rbio->stripe_sectors[i];
1487
1488 if (sector->page == page && sector->pgoff == pgoff)
1489 return sector;
1490 }
1491 return NULL;
1492}
1493
1494/*
1495 * this sets each page in the bio uptodate. It should only be used on private
1496 * rbio pages, nothing that comes in from the higher layers
1497 */
1498static void set_bio_pages_uptodate(struct btrfs_raid_bio *rbio, struct bio *bio)
1499{
1500 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
1501 struct bio_vec *bvec;
1502 struct bvec_iter_all iter_all;
1503
1504 ASSERT(!bio_flagged(bio, BIO_CLONED));
1505
1506 bio_for_each_segment_all(bvec, bio, iter_all) {
1507 struct sector_ptr *sector;
1508 int pgoff;
1509
1510 for (pgoff = bvec->bv_offset; pgoff - bvec->bv_offset < bvec->bv_len;
1511 pgoff += sectorsize) {
1512 sector = find_stripe_sector(rbio, bvec->bv_page, pgoff);
1513 ASSERT(sector);
1514 if (sector)
1515 sector->uptodate = 1;
1516 }
1517 }
1518}
1519
1520static int get_bio_sector_nr(struct btrfs_raid_bio *rbio, struct bio *bio)
1521{
1522 struct bio_vec *bv = bio_first_bvec_all(bio);
1523 int i;
1524
1525 for (i = 0; i < rbio->nr_sectors; i++) {
1526 struct sector_ptr *sector;
1527
1528 sector = &rbio->stripe_sectors[i];
1529 if (sector->page == bv->bv_page && sector->pgoff == bv->bv_offset)
1530 break;
1531 sector = &rbio->bio_sectors[i];
1532 if (sector->page == bv->bv_page && sector->pgoff == bv->bv_offset)
1533 break;
1534 }
1535 ASSERT(i < rbio->nr_sectors);
1536 return i;
1537}
1538
1539static void rbio_update_error_bitmap(struct btrfs_raid_bio *rbio, struct bio *bio)
1540{
1541 int total_sector_nr = get_bio_sector_nr(rbio, bio);
1542 u32 bio_size = 0;
1543 struct bio_vec *bvec;
1544 int i;
1545
1546 bio_for_each_bvec_all(bvec, bio, i)
1547 bio_size += bvec->bv_len;
1548
1549 /*
1550 * Since we can have multiple bios touching the error_bitmap, we cannot
1551 * call bitmap_set() without protection.
1552 *
1553 * Instead use set_bit() for each bit, as set_bit() itself is atomic.
1554 */
1555 for (i = total_sector_nr; i < total_sector_nr +
1556 (bio_size >> rbio->bioc->fs_info->sectorsize_bits); i++)
1557 set_bit(i, rbio->error_bitmap);
1558}
1559
1560/* Verify the data sectors at read time. */
1561static void verify_bio_data_sectors(struct btrfs_raid_bio *rbio,
1562 struct bio *bio)
1563{
1564 struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
1565 int total_sector_nr = get_bio_sector_nr(rbio, bio);
1566 struct bio_vec *bvec;
1567 struct bvec_iter_all iter_all;
1568
1569 /* No data csum for the whole stripe, no need to verify. */
1570 if (!rbio->csum_bitmap || !rbio->csum_buf)
1571 return;
1572
1573 /* P/Q stripes, they have no data csum to verify against. */
1574 if (total_sector_nr >= rbio->nr_data * rbio->stripe_nsectors)
1575 return;
1576
1577 bio_for_each_segment_all(bvec, bio, iter_all) {
1578 int bv_offset;
1579
1580 for (bv_offset = bvec->bv_offset;
1581 bv_offset < bvec->bv_offset + bvec->bv_len;
1582 bv_offset += fs_info->sectorsize, total_sector_nr++) {
1583 u8 csum_buf[BTRFS_CSUM_SIZE];
1584 u8 *expected_csum = rbio->csum_buf +
1585 total_sector_nr * fs_info->csum_size;
1586 int ret;
1587
1588 /* No csum for this sector, skip to the next sector. */
1589 if (!test_bit(total_sector_nr, rbio->csum_bitmap))
1590 continue;
1591
1592 ret = btrfs_check_sector_csum(fs_info, bvec->bv_page,
1593 bv_offset, csum_buf, expected_csum);
1594 if (ret < 0)
1595 set_bit(total_sector_nr, rbio->error_bitmap);
1596 }
1597 }
1598}
1599
1600static void raid_wait_read_end_io(struct bio *bio)
1601{
1602 struct btrfs_raid_bio *rbio = bio->bi_private;
1603
1604 if (bio->bi_status) {
1605 rbio_update_error_bitmap(rbio, bio);
1606 } else {
1607 set_bio_pages_uptodate(rbio, bio);
1608 verify_bio_data_sectors(rbio, bio);
1609 }
1610
1611 bio_put(bio);
1612 if (atomic_dec_and_test(&rbio->stripes_pending))
1613 wake_up(&rbio->io_wait);
1614}
1615
1616static void submit_read_wait_bio_list(struct btrfs_raid_bio *rbio,
1617 struct bio_list *bio_list)
1618{
1619 struct bio *bio;
1620
1621 atomic_set(&rbio->stripes_pending, bio_list_size(bio_list));
1622 while ((bio = bio_list_pop(bio_list))) {
1623 bio->bi_end_io = raid_wait_read_end_io;
1624
1625 if (trace_raid56_read_enabled()) {
1626 struct raid56_bio_trace_info trace_info = { 0 };
1627
1628 bio_get_trace_info(rbio, bio, &trace_info);
1629 trace_raid56_read(rbio, bio, &trace_info);
1630 }
1631 submit_bio(bio);
1632 }
1633
1634 wait_event(rbio->io_wait, atomic_read(&rbio->stripes_pending) == 0);
1635}
1636
1637static int alloc_rbio_data_pages(struct btrfs_raid_bio *rbio)
1638{
1639 const int data_pages = rbio->nr_data * rbio->stripe_npages;
1640 int ret;
1641
1642 ret = btrfs_alloc_page_array(data_pages, rbio->stripe_pages, false);
1643 if (ret < 0)
1644 return ret;
1645
1646 index_stripe_sectors(rbio);
1647 return 0;
1648}
1649
1650/*
1651 * We use plugging call backs to collect full stripes.
1652 * Any time we get a partial stripe write while plugged
1653 * we collect it into a list. When the unplug comes down,
1654 * we sort the list by logical block number and merge
1655 * everything we can into the same rbios
1656 */
1657struct btrfs_plug_cb {
1658 struct blk_plug_cb cb;
1659 struct btrfs_fs_info *info;
1660 struct list_head rbio_list;
1661};
1662
1663/*
1664 * rbios on the plug list are sorted for easier merging.
1665 */
1666static int plug_cmp(void *priv, const struct list_head *a,
1667 const struct list_head *b)
1668{
1669 const struct btrfs_raid_bio *ra = container_of(a, struct btrfs_raid_bio,
1670 plug_list);
1671 const struct btrfs_raid_bio *rb = container_of(b, struct btrfs_raid_bio,
1672 plug_list);
1673 u64 a_sector = ra->bio_list.head->bi_iter.bi_sector;
1674 u64 b_sector = rb->bio_list.head->bi_iter.bi_sector;
1675
1676 if (a_sector < b_sector)
1677 return -1;
1678 if (a_sector > b_sector)
1679 return 1;
1680 return 0;
1681}
1682
1683static void raid_unplug(struct blk_plug_cb *cb, bool from_schedule)
1684{
1685 struct btrfs_plug_cb *plug = container_of(cb, struct btrfs_plug_cb, cb);
1686 struct btrfs_raid_bio *cur;
1687 struct btrfs_raid_bio *last = NULL;
1688
1689 list_sort(NULL, &plug->rbio_list, plug_cmp);
1690
1691 while (!list_empty(&plug->rbio_list)) {
1692 cur = list_entry(plug->rbio_list.next,
1693 struct btrfs_raid_bio, plug_list);
1694 list_del_init(&cur->plug_list);
1695
1696 if (rbio_is_full(cur)) {
1697 /* We have a full stripe, queue it down. */
1698 start_async_work(cur, rmw_rbio_work);
1699 continue;
1700 }
1701 if (last) {
1702 if (rbio_can_merge(last, cur)) {
1703 merge_rbio(last, cur);
1704 free_raid_bio(cur);
1705 continue;
1706 }
1707 start_async_work(last, rmw_rbio_work);
1708 }
1709 last = cur;
1710 }
1711 if (last)
1712 start_async_work(last, rmw_rbio_work);
1713 kfree(plug);
1714}
1715
1716/* Add the original bio into rbio->bio_list, and update rbio::dbitmap. */
1717static void rbio_add_bio(struct btrfs_raid_bio *rbio, struct bio *orig_bio)
1718{
1719 const struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
1720 const u64 orig_logical = orig_bio->bi_iter.bi_sector << SECTOR_SHIFT;
1721 const u64 full_stripe_start = rbio->bioc->full_stripe_logical;
1722 const u32 orig_len = orig_bio->bi_iter.bi_size;
1723 const u32 sectorsize = fs_info->sectorsize;
1724 u64 cur_logical;
1725
1726 ASSERT_RBIO_LOGICAL(orig_logical >= full_stripe_start &&
1727 orig_logical + orig_len <= full_stripe_start +
1728 rbio->nr_data * BTRFS_STRIPE_LEN,
1729 rbio, orig_logical);
1730
1731 bio_list_add(&rbio->bio_list, orig_bio);
1732 rbio->bio_list_bytes += orig_bio->bi_iter.bi_size;
1733
1734 /* Update the dbitmap. */
1735 for (cur_logical = orig_logical; cur_logical < orig_logical + orig_len;
1736 cur_logical += sectorsize) {
1737 int bit = ((u32)(cur_logical - full_stripe_start) >>
1738 fs_info->sectorsize_bits) % rbio->stripe_nsectors;
1739
1740 set_bit(bit, &rbio->dbitmap);
1741 }
1742}
1743
1744/*
1745 * our main entry point for writes from the rest of the FS.
1746 */
1747void raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc)
1748{
1749 struct btrfs_fs_info *fs_info = bioc->fs_info;
1750 struct btrfs_raid_bio *rbio;
1751 struct btrfs_plug_cb *plug = NULL;
1752 struct blk_plug_cb *cb;
1753
1754 rbio = alloc_rbio(fs_info, bioc);
1755 if (IS_ERR(rbio)) {
1756 bio->bi_status = errno_to_blk_status(PTR_ERR(rbio));
1757 bio_endio(bio);
1758 return;
1759 }
1760 rbio->operation = BTRFS_RBIO_WRITE;
1761 rbio_add_bio(rbio, bio);
1762
1763 /*
1764 * Don't plug on full rbios, just get them out the door
1765 * as quickly as we can
1766 */
1767 if (!rbio_is_full(rbio)) {
1768 cb = blk_check_plugged(raid_unplug, fs_info, sizeof(*plug));
1769 if (cb) {
1770 plug = container_of(cb, struct btrfs_plug_cb, cb);
1771 if (!plug->info) {
1772 plug->info = fs_info;
1773 INIT_LIST_HEAD(&plug->rbio_list);
1774 }
1775 list_add_tail(&rbio->plug_list, &plug->rbio_list);
1776 return;
1777 }
1778 }
1779
1780 /*
1781 * Either we don't have any existing plug, or we're doing a full stripe,
1782 * queue the rmw work now.
1783 */
1784 start_async_work(rbio, rmw_rbio_work);
1785}
1786
1787static int verify_one_sector(struct btrfs_raid_bio *rbio,
1788 int stripe_nr, int sector_nr)
1789{
1790 struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
1791 struct sector_ptr *sector;
1792 u8 csum_buf[BTRFS_CSUM_SIZE];
1793 u8 *csum_expected;
1794 int ret;
1795
1796 if (!rbio->csum_bitmap || !rbio->csum_buf)
1797 return 0;
1798
1799 /* No way to verify P/Q as they are not covered by data csum. */
1800 if (stripe_nr >= rbio->nr_data)
1801 return 0;
1802 /*
1803 * If we're rebuilding a read, we have to use pages from the
1804 * bio list if possible.
1805 */
1806 if (rbio->operation == BTRFS_RBIO_READ_REBUILD) {
1807 sector = sector_in_rbio(rbio, stripe_nr, sector_nr, 0);
1808 } else {
1809 sector = rbio_stripe_sector(rbio, stripe_nr, sector_nr);
1810 }
1811
1812 ASSERT(sector->page);
1813
1814 csum_expected = rbio->csum_buf +
1815 (stripe_nr * rbio->stripe_nsectors + sector_nr) *
1816 fs_info->csum_size;
1817 ret = btrfs_check_sector_csum(fs_info, sector->page, sector->pgoff,
1818 csum_buf, csum_expected);
1819 return ret;
1820}
1821
1822/*
1823 * Recover a vertical stripe specified by @sector_nr.
1824 * @*pointers are the pre-allocated pointers by the caller, so we don't
1825 * need to allocate/free the pointers again and again.
1826 */
1827static int recover_vertical(struct btrfs_raid_bio *rbio, int sector_nr,
1828 void **pointers, void **unmap_array)
1829{
1830 struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
1831 struct sector_ptr *sector;
1832 const u32 sectorsize = fs_info->sectorsize;
1833 int found_errors;
1834 int faila;
1835 int failb;
1836 int stripe_nr;
1837 int ret = 0;
1838
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(sector_nr, &rbio->dbitmap))
1845 return 0;
1846
1847 found_errors = get_rbio_veritical_errors(rbio, sector_nr, &faila,
1848 &failb);
1849 /*
1850 * No errors in the vertical stripe, skip it. Can happen for recovery
1851 * which only part of a stripe failed csum check.
1852 */
1853 if (!found_errors)
1854 return 0;
1855
1856 if (found_errors > rbio->bioc->max_errors)
1857 return -EIO;
1858
1859 /*
1860 * Setup our array of pointers with sectors from each stripe
1861 *
1862 * NOTE: store a duplicate array of pointers to preserve the
1863 * pointer order.
1864 */
1865 for (stripe_nr = 0; stripe_nr < rbio->real_stripes; stripe_nr++) {
1866 /*
1867 * If we're rebuilding a read, we have to use pages from the
1868 * bio list if possible.
1869 */
1870 if (rbio->operation == BTRFS_RBIO_READ_REBUILD) {
1871 sector = sector_in_rbio(rbio, stripe_nr, sector_nr, 0);
1872 } else {
1873 sector = rbio_stripe_sector(rbio, stripe_nr, sector_nr);
1874 }
1875 ASSERT(sector->page);
1876 pointers[stripe_nr] = kmap_local_page(sector->page) +
1877 sector->pgoff;
1878 unmap_array[stripe_nr] = pointers[stripe_nr];
1879 }
1880
1881 /* All raid6 handling here */
1882 if (rbio->bioc->map_type & BTRFS_BLOCK_GROUP_RAID6) {
1883 /* Single failure, rebuild from parity raid5 style */
1884 if (failb < 0) {
1885 if (faila == rbio->nr_data)
1886 /*
1887 * Just the P stripe has failed, without
1888 * a bad data or Q stripe.
1889 * We have nothing to do, just skip the
1890 * recovery for this stripe.
1891 */
1892 goto cleanup;
1893 /*
1894 * a single failure in raid6 is rebuilt
1895 * in the pstripe code below
1896 */
1897 goto pstripe;
1898 }
1899
1900 /*
1901 * If the q stripe is failed, do a pstripe reconstruction from
1902 * the xors.
1903 * If both the q stripe and the P stripe are failed, we're
1904 * here due to a crc mismatch and we can't give them the
1905 * data they want.
1906 */
1907 if (failb == rbio->real_stripes - 1) {
1908 if (faila == rbio->real_stripes - 2)
1909 /*
1910 * Only P and Q are corrupted.
1911 * We only care about data stripes recovery,
1912 * can skip this vertical stripe.
1913 */
1914 goto cleanup;
1915 /*
1916 * Otherwise we have one bad data stripe and
1917 * a good P stripe. raid5!
1918 */
1919 goto pstripe;
1920 }
1921
1922 if (failb == rbio->real_stripes - 2) {
1923 raid6_datap_recov(rbio->real_stripes, sectorsize,
1924 faila, pointers);
1925 } else {
1926 raid6_2data_recov(rbio->real_stripes, sectorsize,
1927 faila, failb, pointers);
1928 }
1929 } else {
1930 void *p;
1931
1932 /* Rebuild from P stripe here (raid5 or raid6). */
1933 ASSERT(failb == -1);
1934pstripe:
1935 /* Copy parity block into failed block to start with */
1936 memcpy(pointers[faila], pointers[rbio->nr_data], sectorsize);
1937
1938 /* Rearrange the pointer array */
1939 p = pointers[faila];
1940 for (stripe_nr = faila; stripe_nr < rbio->nr_data - 1;
1941 stripe_nr++)
1942 pointers[stripe_nr] = pointers[stripe_nr + 1];
1943 pointers[rbio->nr_data - 1] = p;
1944
1945 /* Xor in the rest */
1946 run_xor(pointers, rbio->nr_data - 1, sectorsize);
1947
1948 }
1949
1950 /*
1951 * No matter if this is a RMW or recovery, we should have all
1952 * failed sectors repaired in the vertical stripe, thus they are now
1953 * uptodate.
1954 * Especially if we determine to cache the rbio, we need to
1955 * have at least all data sectors uptodate.
1956 *
1957 * If possible, also check if the repaired sector matches its data
1958 * checksum.
1959 */
1960 if (faila >= 0) {
1961 ret = verify_one_sector(rbio, faila, sector_nr);
1962 if (ret < 0)
1963 goto cleanup;
1964
1965 sector = rbio_stripe_sector(rbio, faila, sector_nr);
1966 sector->uptodate = 1;
1967 }
1968 if (failb >= 0) {
1969 ret = verify_one_sector(rbio, failb, sector_nr);
1970 if (ret < 0)
1971 goto cleanup;
1972
1973 sector = rbio_stripe_sector(rbio, failb, sector_nr);
1974 sector->uptodate = 1;
1975 }
1976
1977cleanup:
1978 for (stripe_nr = rbio->real_stripes - 1; stripe_nr >= 0; stripe_nr--)
1979 kunmap_local(unmap_array[stripe_nr]);
1980 return ret;
1981}
1982
1983static int recover_sectors(struct btrfs_raid_bio *rbio)
1984{
1985 void **pointers = NULL;
1986 void **unmap_array = NULL;
1987 int sectornr;
1988 int ret = 0;
1989
1990 /*
1991 * @pointers array stores the pointer for each sector.
1992 *
1993 * @unmap_array stores copy of pointers that does not get reordered
1994 * during reconstruction so that kunmap_local works.
1995 */
1996 pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
1997 unmap_array = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
1998 if (!pointers || !unmap_array) {
1999 ret = -ENOMEM;
2000 goto out;
2001 }
2002
2003 if (rbio->operation == BTRFS_RBIO_READ_REBUILD) {
2004 spin_lock(&rbio->bio_list_lock);
2005 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
2006 spin_unlock(&rbio->bio_list_lock);
2007 }
2008
2009 index_rbio_pages(rbio);
2010
2011 for (sectornr = 0; sectornr < rbio->stripe_nsectors; sectornr++) {
2012 ret = recover_vertical(rbio, sectornr, pointers, unmap_array);
2013 if (ret < 0)
2014 break;
2015 }
2016
2017out:
2018 kfree(pointers);
2019 kfree(unmap_array);
2020 return ret;
2021}
2022
2023static void recover_rbio(struct btrfs_raid_bio *rbio)
2024{
2025 struct bio_list bio_list = BIO_EMPTY_LIST;
2026 int total_sector_nr;
2027 int ret = 0;
2028
2029 /*
2030 * Either we're doing recover for a read failure or degraded write,
2031 * caller should have set error bitmap correctly.
2032 */
2033 ASSERT(bitmap_weight(rbio->error_bitmap, rbio->nr_sectors));
2034
2035 /* For recovery, we need to read all sectors including P/Q. */
2036 ret = alloc_rbio_pages(rbio);
2037 if (ret < 0)
2038 goto out;
2039
2040 index_rbio_pages(rbio);
2041
2042 /*
2043 * Read everything that hasn't failed. However this time we will
2044 * not trust any cached sector.
2045 * As we may read out some stale data but higher layer is not reading
2046 * that stale part.
2047 *
2048 * So here we always re-read everything in recovery path.
2049 */
2050 for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
2051 total_sector_nr++) {
2052 int stripe = total_sector_nr / rbio->stripe_nsectors;
2053 int sectornr = total_sector_nr % rbio->stripe_nsectors;
2054 struct sector_ptr *sector;
2055
2056 /*
2057 * Skip the range which has error. It can be a range which is
2058 * marked error (for csum mismatch), or it can be a missing
2059 * device.
2060 */
2061 if (!rbio->bioc->stripes[stripe].dev->bdev ||
2062 test_bit(total_sector_nr, rbio->error_bitmap)) {
2063 /*
2064 * Also set the error bit for missing device, which
2065 * may not yet have its error bit set.
2066 */
2067 set_bit(total_sector_nr, rbio->error_bitmap);
2068 continue;
2069 }
2070
2071 sector = rbio_stripe_sector(rbio, stripe, sectornr);
2072 ret = rbio_add_io_sector(rbio, &bio_list, sector, stripe,
2073 sectornr, REQ_OP_READ);
2074 if (ret < 0) {
2075 bio_list_put(&bio_list);
2076 goto out;
2077 }
2078 }
2079
2080 submit_read_wait_bio_list(rbio, &bio_list);
2081 ret = recover_sectors(rbio);
2082out:
2083 rbio_orig_end_io(rbio, errno_to_blk_status(ret));
2084}
2085
2086static void recover_rbio_work(struct work_struct *work)
2087{
2088 struct btrfs_raid_bio *rbio;
2089
2090 rbio = container_of(work, struct btrfs_raid_bio, work);
2091 if (!lock_stripe_add(rbio))
2092 recover_rbio(rbio);
2093}
2094
2095static void recover_rbio_work_locked(struct work_struct *work)
2096{
2097 recover_rbio(container_of(work, struct btrfs_raid_bio, work));
2098}
2099
2100static void set_rbio_raid6_extra_error(struct btrfs_raid_bio *rbio, int mirror_num)
2101{
2102 bool found = false;
2103 int sector_nr;
2104
2105 /*
2106 * This is for RAID6 extra recovery tries, thus mirror number should
2107 * be large than 2.
2108 * Mirror 1 means read from data stripes. Mirror 2 means rebuild using
2109 * RAID5 methods.
2110 */
2111 ASSERT(mirror_num > 2);
2112 for (sector_nr = 0; sector_nr < rbio->stripe_nsectors; sector_nr++) {
2113 int found_errors;
2114 int faila;
2115 int failb;
2116
2117 found_errors = get_rbio_veritical_errors(rbio, sector_nr,
2118 &faila, &failb);
2119 /* This vertical stripe doesn't have errors. */
2120 if (!found_errors)
2121 continue;
2122
2123 /*
2124 * If we found errors, there should be only one error marked
2125 * by previous set_rbio_range_error().
2126 */
2127 ASSERT(found_errors == 1);
2128 found = true;
2129
2130 /* Now select another stripe to mark as error. */
2131 failb = rbio->real_stripes - (mirror_num - 1);
2132 if (failb <= faila)
2133 failb--;
2134
2135 /* Set the extra bit in error bitmap. */
2136 if (failb >= 0)
2137 set_bit(failb * rbio->stripe_nsectors + sector_nr,
2138 rbio->error_bitmap);
2139 }
2140
2141 /* We should found at least one vertical stripe with error.*/
2142 ASSERT(found);
2143}
2144
2145/*
2146 * the main entry point for reads from the higher layers. This
2147 * is really only called when the normal read path had a failure,
2148 * so we assume the bio they send down corresponds to a failed part
2149 * of the drive.
2150 */
2151void raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
2152 int mirror_num)
2153{
2154 struct btrfs_fs_info *fs_info = bioc->fs_info;
2155 struct btrfs_raid_bio *rbio;
2156
2157 rbio = alloc_rbio(fs_info, bioc);
2158 if (IS_ERR(rbio)) {
2159 bio->bi_status = errno_to_blk_status(PTR_ERR(rbio));
2160 bio_endio(bio);
2161 return;
2162 }
2163
2164 rbio->operation = BTRFS_RBIO_READ_REBUILD;
2165 rbio_add_bio(rbio, bio);
2166
2167 set_rbio_range_error(rbio, bio);
2168
2169 /*
2170 * Loop retry:
2171 * for 'mirror == 2', reconstruct from all other stripes.
2172 * for 'mirror_num > 2', select a stripe to fail on every retry.
2173 */
2174 if (mirror_num > 2)
2175 set_rbio_raid6_extra_error(rbio, mirror_num);
2176
2177 start_async_work(rbio, recover_rbio_work);
2178}
2179
2180static void fill_data_csums(struct btrfs_raid_bio *rbio)
2181{
2182 struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
2183 struct btrfs_root *csum_root = btrfs_csum_root(fs_info,
2184 rbio->bioc->full_stripe_logical);
2185 const u64 start = rbio->bioc->full_stripe_logical;
2186 const u32 len = (rbio->nr_data * rbio->stripe_nsectors) <<
2187 fs_info->sectorsize_bits;
2188 int ret;
2189
2190 /* The rbio should not have its csum buffer initialized. */
2191 ASSERT(!rbio->csum_buf && !rbio->csum_bitmap);
2192
2193 /*
2194 * Skip the csum search if:
2195 *
2196 * - The rbio doesn't belong to data block groups
2197 * Then we are doing IO for tree blocks, no need to search csums.
2198 *
2199 * - The rbio belongs to mixed block groups
2200 * This is to avoid deadlock, as we're already holding the full
2201 * stripe lock, if we trigger a metadata read, and it needs to do
2202 * raid56 recovery, we will deadlock.
2203 */
2204 if (!(rbio->bioc->map_type & BTRFS_BLOCK_GROUP_DATA) ||
2205 rbio->bioc->map_type & BTRFS_BLOCK_GROUP_METADATA)
2206 return;
2207
2208 rbio->csum_buf = kzalloc(rbio->nr_data * rbio->stripe_nsectors *
2209 fs_info->csum_size, GFP_NOFS);
2210 rbio->csum_bitmap = bitmap_zalloc(rbio->nr_data * rbio->stripe_nsectors,
2211 GFP_NOFS);
2212 if (!rbio->csum_buf || !rbio->csum_bitmap) {
2213 ret = -ENOMEM;
2214 goto error;
2215 }
2216
2217 ret = btrfs_lookup_csums_bitmap(csum_root, NULL, start, start + len - 1,
2218 rbio->csum_buf, rbio->csum_bitmap);
2219 if (ret < 0)
2220 goto error;
2221 if (bitmap_empty(rbio->csum_bitmap, len >> fs_info->sectorsize_bits))
2222 goto no_csum;
2223 return;
2224
2225error:
2226 /*
2227 * We failed to allocate memory or grab the csum, but it's not fatal,
2228 * we can still continue. But better to warn users that RMW is no
2229 * longer safe for this particular sub-stripe write.
2230 */
2231 btrfs_warn_rl(fs_info,
2232"sub-stripe write for full stripe %llu is not safe, failed to get csum: %d",
2233 rbio->bioc->full_stripe_logical, ret);
2234no_csum:
2235 kfree(rbio->csum_buf);
2236 bitmap_free(rbio->csum_bitmap);
2237 rbio->csum_buf = NULL;
2238 rbio->csum_bitmap = NULL;
2239}
2240
2241static int rmw_read_wait_recover(struct btrfs_raid_bio *rbio)
2242{
2243 struct bio_list bio_list = BIO_EMPTY_LIST;
2244 int total_sector_nr;
2245 int ret = 0;
2246
2247 /*
2248 * Fill the data csums we need for data verification. We need to fill
2249 * the csum_bitmap/csum_buf first, as our endio function will try to
2250 * verify the data sectors.
2251 */
2252 fill_data_csums(rbio);
2253
2254 /*
2255 * Build a list of bios to read all sectors (including data and P/Q).
2256 *
2257 * This behavior is to compensate the later csum verification and recovery.
2258 */
2259 for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
2260 total_sector_nr++) {
2261 struct sector_ptr *sector;
2262 int stripe = total_sector_nr / rbio->stripe_nsectors;
2263 int sectornr = total_sector_nr % rbio->stripe_nsectors;
2264
2265 sector = rbio_stripe_sector(rbio, stripe, sectornr);
2266 ret = rbio_add_io_sector(rbio, &bio_list, sector,
2267 stripe, sectornr, REQ_OP_READ);
2268 if (ret) {
2269 bio_list_put(&bio_list);
2270 return ret;
2271 }
2272 }
2273
2274 /*
2275 * We may or may not have any corrupted sectors (including missing dev
2276 * and csum mismatch), just let recover_sectors() to handle them all.
2277 */
2278 submit_read_wait_bio_list(rbio, &bio_list);
2279 return recover_sectors(rbio);
2280}
2281
2282static void raid_wait_write_end_io(struct bio *bio)
2283{
2284 struct btrfs_raid_bio *rbio = bio->bi_private;
2285 blk_status_t err = bio->bi_status;
2286
2287 if (err)
2288 rbio_update_error_bitmap(rbio, bio);
2289 bio_put(bio);
2290 if (atomic_dec_and_test(&rbio->stripes_pending))
2291 wake_up(&rbio->io_wait);
2292}
2293
2294static void submit_write_bios(struct btrfs_raid_bio *rbio,
2295 struct bio_list *bio_list)
2296{
2297 struct bio *bio;
2298
2299 atomic_set(&rbio->stripes_pending, bio_list_size(bio_list));
2300 while ((bio = bio_list_pop(bio_list))) {
2301 bio->bi_end_io = raid_wait_write_end_io;
2302
2303 if (trace_raid56_write_enabled()) {
2304 struct raid56_bio_trace_info trace_info = { 0 };
2305
2306 bio_get_trace_info(rbio, bio, &trace_info);
2307 trace_raid56_write(rbio, bio, &trace_info);
2308 }
2309 submit_bio(bio);
2310 }
2311}
2312
2313/*
2314 * To determine if we need to read any sector from the disk.
2315 * Should only be utilized in RMW path, to skip cached rbio.
2316 */
2317static bool need_read_stripe_sectors(struct btrfs_raid_bio *rbio)
2318{
2319 int i;
2320
2321 for (i = 0; i < rbio->nr_data * rbio->stripe_nsectors; i++) {
2322 struct sector_ptr *sector = &rbio->stripe_sectors[i];
2323
2324 /*
2325 * We have a sector which doesn't have page nor uptodate,
2326 * thus this rbio can not be cached one, as cached one must
2327 * have all its data sectors present and uptodate.
2328 */
2329 if (!sector->page || !sector->uptodate)
2330 return true;
2331 }
2332 return false;
2333}
2334
2335static void rmw_rbio(struct btrfs_raid_bio *rbio)
2336{
2337 struct bio_list bio_list;
2338 int sectornr;
2339 int ret = 0;
2340
2341 /*
2342 * Allocate the pages for parity first, as P/Q pages will always be
2343 * needed for both full-stripe and sub-stripe writes.
2344 */
2345 ret = alloc_rbio_parity_pages(rbio);
2346 if (ret < 0)
2347 goto out;
2348
2349 /*
2350 * Either full stripe write, or we have every data sector already
2351 * cached, can go to write path immediately.
2352 */
2353 if (!rbio_is_full(rbio) && need_read_stripe_sectors(rbio)) {
2354 /*
2355 * Now we're doing sub-stripe write, also need all data stripes
2356 * to do the full RMW.
2357 */
2358 ret = alloc_rbio_data_pages(rbio);
2359 if (ret < 0)
2360 goto out;
2361
2362 index_rbio_pages(rbio);
2363
2364 ret = rmw_read_wait_recover(rbio);
2365 if (ret < 0)
2366 goto out;
2367 }
2368
2369 /*
2370 * At this stage we're not allowed to add any new bios to the
2371 * bio list any more, anyone else that wants to change this stripe
2372 * needs to do their own rmw.
2373 */
2374 spin_lock(&rbio->bio_list_lock);
2375 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
2376 spin_unlock(&rbio->bio_list_lock);
2377
2378 bitmap_clear(rbio->error_bitmap, 0, rbio->nr_sectors);
2379
2380 index_rbio_pages(rbio);
2381
2382 /*
2383 * We don't cache full rbios because we're assuming
2384 * the higher layers are unlikely to use this area of
2385 * the disk again soon. If they do use it again,
2386 * hopefully they will send another full bio.
2387 */
2388 if (!rbio_is_full(rbio))
2389 cache_rbio_pages(rbio);
2390 else
2391 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
2392
2393 for (sectornr = 0; sectornr < rbio->stripe_nsectors; sectornr++)
2394 generate_pq_vertical(rbio, sectornr);
2395
2396 bio_list_init(&bio_list);
2397 ret = rmw_assemble_write_bios(rbio, &bio_list);
2398 if (ret < 0)
2399 goto out;
2400
2401 /* We should have at least one bio assembled. */
2402 ASSERT(bio_list_size(&bio_list));
2403 submit_write_bios(rbio, &bio_list);
2404 wait_event(rbio->io_wait, atomic_read(&rbio->stripes_pending) == 0);
2405
2406 /* We may have more errors than our tolerance during the read. */
2407 for (sectornr = 0; sectornr < rbio->stripe_nsectors; sectornr++) {
2408 int found_errors;
2409
2410 found_errors = get_rbio_veritical_errors(rbio, sectornr, NULL, NULL);
2411 if (found_errors > rbio->bioc->max_errors) {
2412 ret = -EIO;
2413 break;
2414 }
2415 }
2416out:
2417 rbio_orig_end_io(rbio, errno_to_blk_status(ret));
2418}
2419
2420static void rmw_rbio_work(struct work_struct *work)
2421{
2422 struct btrfs_raid_bio *rbio;
2423
2424 rbio = container_of(work, struct btrfs_raid_bio, work);
2425 if (lock_stripe_add(rbio) == 0)
2426 rmw_rbio(rbio);
2427}
2428
2429static void rmw_rbio_work_locked(struct work_struct *work)
2430{
2431 rmw_rbio(container_of(work, struct btrfs_raid_bio, work));
2432}
2433
2434/*
2435 * The following code is used to scrub/replace the parity stripe
2436 *
2437 * Caller must have already increased bio_counter for getting @bioc.
2438 *
2439 * Note: We need make sure all the pages that add into the scrub/replace
2440 * raid bio are correct and not be changed during the scrub/replace. That
2441 * is those pages just hold metadata or file data with checksum.
2442 */
2443
2444struct btrfs_raid_bio *raid56_parity_alloc_scrub_rbio(struct bio *bio,
2445 struct btrfs_io_context *bioc,
2446 struct btrfs_device *scrub_dev,
2447 unsigned long *dbitmap, int stripe_nsectors)
2448{
2449 struct btrfs_fs_info *fs_info = bioc->fs_info;
2450 struct btrfs_raid_bio *rbio;
2451 int i;
2452
2453 rbio = alloc_rbio(fs_info, bioc);
2454 if (IS_ERR(rbio))
2455 return NULL;
2456 bio_list_add(&rbio->bio_list, bio);
2457 /*
2458 * This is a special bio which is used to hold the completion handler
2459 * and make the scrub rbio is similar to the other types
2460 */
2461 ASSERT(!bio->bi_iter.bi_size);
2462 rbio->operation = BTRFS_RBIO_PARITY_SCRUB;
2463
2464 /*
2465 * After mapping bioc with BTRFS_MAP_WRITE, parities have been sorted
2466 * to the end position, so this search can start from the first parity
2467 * stripe.
2468 */
2469 for (i = rbio->nr_data; i < rbio->real_stripes; i++) {
2470 if (bioc->stripes[i].dev == scrub_dev) {
2471 rbio->scrubp = i;
2472 break;
2473 }
2474 }
2475 ASSERT_RBIO_STRIPE(i < rbio->real_stripes, rbio, i);
2476
2477 bitmap_copy(&rbio->dbitmap, dbitmap, stripe_nsectors);
2478 return rbio;
2479}
2480
2481/*
2482 * We just scrub the parity that we have correct data on the same horizontal,
2483 * so we needn't allocate all pages for all the stripes.
2484 */
2485static int alloc_rbio_essential_pages(struct btrfs_raid_bio *rbio)
2486{
2487 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
2488 int total_sector_nr;
2489
2490 for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
2491 total_sector_nr++) {
2492 struct page *page;
2493 int sectornr = total_sector_nr % rbio->stripe_nsectors;
2494 int index = (total_sector_nr * sectorsize) >> PAGE_SHIFT;
2495
2496 if (!test_bit(sectornr, &rbio->dbitmap))
2497 continue;
2498 if (rbio->stripe_pages[index])
2499 continue;
2500 page = alloc_page(GFP_NOFS);
2501 if (!page)
2502 return -ENOMEM;
2503 rbio->stripe_pages[index] = page;
2504 }
2505 index_stripe_sectors(rbio);
2506 return 0;
2507}
2508
2509static int finish_parity_scrub(struct btrfs_raid_bio *rbio)
2510{
2511 struct btrfs_io_context *bioc = rbio->bioc;
2512 const u32 sectorsize = bioc->fs_info->sectorsize;
2513 void **pointers = rbio->finish_pointers;
2514 unsigned long *pbitmap = &rbio->finish_pbitmap;
2515 int nr_data = rbio->nr_data;
2516 int stripe;
2517 int sectornr;
2518 bool has_qstripe;
2519 struct sector_ptr p_sector = { 0 };
2520 struct sector_ptr q_sector = { 0 };
2521 struct bio_list bio_list;
2522 int is_replace = 0;
2523 int ret;
2524
2525 bio_list_init(&bio_list);
2526
2527 if (rbio->real_stripes - rbio->nr_data == 1)
2528 has_qstripe = false;
2529 else if (rbio->real_stripes - rbio->nr_data == 2)
2530 has_qstripe = true;
2531 else
2532 BUG();
2533
2534 /*
2535 * Replace is running and our P/Q stripe is being replaced, then we
2536 * need to duplicate the final write to replace target.
2537 */
2538 if (bioc->replace_nr_stripes && bioc->replace_stripe_src == rbio->scrubp) {
2539 is_replace = 1;
2540 bitmap_copy(pbitmap, &rbio->dbitmap, rbio->stripe_nsectors);
2541 }
2542
2543 /*
2544 * Because the higher layers(scrubber) are unlikely to
2545 * use this area of the disk again soon, so don't cache
2546 * it.
2547 */
2548 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
2549
2550 p_sector.page = alloc_page(GFP_NOFS);
2551 if (!p_sector.page)
2552 return -ENOMEM;
2553 p_sector.pgoff = 0;
2554 p_sector.uptodate = 1;
2555
2556 if (has_qstripe) {
2557 /* RAID6, allocate and map temp space for the Q stripe */
2558 q_sector.page = alloc_page(GFP_NOFS);
2559 if (!q_sector.page) {
2560 __free_page(p_sector.page);
2561 p_sector.page = NULL;
2562 return -ENOMEM;
2563 }
2564 q_sector.pgoff = 0;
2565 q_sector.uptodate = 1;
2566 pointers[rbio->real_stripes - 1] = kmap_local_page(q_sector.page);
2567 }
2568
2569 bitmap_clear(rbio->error_bitmap, 0, rbio->nr_sectors);
2570
2571 /* Map the parity stripe just once */
2572 pointers[nr_data] = kmap_local_page(p_sector.page);
2573
2574 for_each_set_bit(sectornr, &rbio->dbitmap, rbio->stripe_nsectors) {
2575 struct sector_ptr *sector;
2576 void *parity;
2577
2578 /* first collect one page from each data stripe */
2579 for (stripe = 0; stripe < nr_data; stripe++) {
2580 sector = sector_in_rbio(rbio, stripe, sectornr, 0);
2581 pointers[stripe] = kmap_local_page(sector->page) +
2582 sector->pgoff;
2583 }
2584
2585 if (has_qstripe) {
2586 assert_rbio(rbio);
2587 /* RAID6, call the library function to fill in our P/Q */
2588 raid6_call.gen_syndrome(rbio->real_stripes, sectorsize,
2589 pointers);
2590 } else {
2591 /* raid5 */
2592 memcpy(pointers[nr_data], pointers[0], sectorsize);
2593 run_xor(pointers + 1, nr_data - 1, sectorsize);
2594 }
2595
2596 /* Check scrubbing parity and repair it */
2597 sector = rbio_stripe_sector(rbio, rbio->scrubp, sectornr);
2598 parity = kmap_local_page(sector->page) + sector->pgoff;
2599 if (memcmp(parity, pointers[rbio->scrubp], sectorsize) != 0)
2600 memcpy(parity, pointers[rbio->scrubp], sectorsize);
2601 else
2602 /* Parity is right, needn't writeback */
2603 bitmap_clear(&rbio->dbitmap, sectornr, 1);
2604 kunmap_local(parity);
2605
2606 for (stripe = nr_data - 1; stripe >= 0; stripe--)
2607 kunmap_local(pointers[stripe]);
2608 }
2609
2610 kunmap_local(pointers[nr_data]);
2611 __free_page(p_sector.page);
2612 p_sector.page = NULL;
2613 if (q_sector.page) {
2614 kunmap_local(pointers[rbio->real_stripes - 1]);
2615 __free_page(q_sector.page);
2616 q_sector.page = NULL;
2617 }
2618
2619 /*
2620 * time to start writing. Make bios for everything from the
2621 * higher layers (the bio_list in our rbio) and our p/q. Ignore
2622 * everything else.
2623 */
2624 for_each_set_bit(sectornr, &rbio->dbitmap, rbio->stripe_nsectors) {
2625 struct sector_ptr *sector;
2626
2627 sector = rbio_stripe_sector(rbio, rbio->scrubp, sectornr);
2628 ret = rbio_add_io_sector(rbio, &bio_list, sector, rbio->scrubp,
2629 sectornr, REQ_OP_WRITE);
2630 if (ret)
2631 goto cleanup;
2632 }
2633
2634 if (!is_replace)
2635 goto submit_write;
2636
2637 /*
2638 * Replace is running and our parity stripe needs to be duplicated to
2639 * the target device. Check we have a valid source stripe number.
2640 */
2641 ASSERT_RBIO(rbio->bioc->replace_stripe_src >= 0, rbio);
2642 for_each_set_bit(sectornr, pbitmap, rbio->stripe_nsectors) {
2643 struct sector_ptr *sector;
2644
2645 sector = rbio_stripe_sector(rbio, rbio->scrubp, sectornr);
2646 ret = rbio_add_io_sector(rbio, &bio_list, sector,
2647 rbio->real_stripes,
2648 sectornr, REQ_OP_WRITE);
2649 if (ret)
2650 goto cleanup;
2651 }
2652
2653submit_write:
2654 submit_write_bios(rbio, &bio_list);
2655 return 0;
2656
2657cleanup:
2658 bio_list_put(&bio_list);
2659 return ret;
2660}
2661
2662static inline int is_data_stripe(struct btrfs_raid_bio *rbio, int stripe)
2663{
2664 if (stripe >= 0 && stripe < rbio->nr_data)
2665 return 1;
2666 return 0;
2667}
2668
2669static int recover_scrub_rbio(struct btrfs_raid_bio *rbio)
2670{
2671 void **pointers = NULL;
2672 void **unmap_array = NULL;
2673 int sector_nr;
2674 int ret = 0;
2675
2676 /*
2677 * @pointers array stores the pointer for each sector.
2678 *
2679 * @unmap_array stores copy of pointers that does not get reordered
2680 * during reconstruction so that kunmap_local works.
2681 */
2682 pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
2683 unmap_array = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
2684 if (!pointers || !unmap_array) {
2685 ret = -ENOMEM;
2686 goto out;
2687 }
2688
2689 for (sector_nr = 0; sector_nr < rbio->stripe_nsectors; sector_nr++) {
2690 int dfail = 0, failp = -1;
2691 int faila;
2692 int failb;
2693 int found_errors;
2694
2695 found_errors = get_rbio_veritical_errors(rbio, sector_nr,
2696 &faila, &failb);
2697 if (found_errors > rbio->bioc->max_errors) {
2698 ret = -EIO;
2699 goto out;
2700 }
2701 if (found_errors == 0)
2702 continue;
2703
2704 /* We should have at least one error here. */
2705 ASSERT(faila >= 0 || failb >= 0);
2706
2707 if (is_data_stripe(rbio, faila))
2708 dfail++;
2709 else if (is_parity_stripe(faila))
2710 failp = faila;
2711
2712 if (is_data_stripe(rbio, failb))
2713 dfail++;
2714 else if (is_parity_stripe(failb))
2715 failp = failb;
2716 /*
2717 * Because we can not use a scrubbing parity to repair the
2718 * data, so the capability of the repair is declined. (In the
2719 * case of RAID5, we can not repair anything.)
2720 */
2721 if (dfail > rbio->bioc->max_errors - 1) {
2722 ret = -EIO;
2723 goto out;
2724 }
2725 /*
2726 * If all data is good, only parity is correctly, just repair
2727 * the parity, no need to recover data stripes.
2728 */
2729 if (dfail == 0)
2730 continue;
2731
2732 /*
2733 * Here means we got one corrupted data stripe and one
2734 * corrupted parity on RAID6, if the corrupted parity is
2735 * scrubbing parity, luckily, use the other one to repair the
2736 * data, or we can not repair the data stripe.
2737 */
2738 if (failp != rbio->scrubp) {
2739 ret = -EIO;
2740 goto out;
2741 }
2742
2743 ret = recover_vertical(rbio, sector_nr, pointers, unmap_array);
2744 if (ret < 0)
2745 goto out;
2746 }
2747out:
2748 kfree(pointers);
2749 kfree(unmap_array);
2750 return ret;
2751}
2752
2753static int scrub_assemble_read_bios(struct btrfs_raid_bio *rbio)
2754{
2755 struct bio_list bio_list = BIO_EMPTY_LIST;
2756 int total_sector_nr;
2757 int ret = 0;
2758
2759 /* Build a list of bios to read all the missing parts. */
2760 for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
2761 total_sector_nr++) {
2762 int sectornr = total_sector_nr % rbio->stripe_nsectors;
2763 int stripe = total_sector_nr / rbio->stripe_nsectors;
2764 struct sector_ptr *sector;
2765
2766 /* No data in the vertical stripe, no need to read. */
2767 if (!test_bit(sectornr, &rbio->dbitmap))
2768 continue;
2769
2770 /*
2771 * We want to find all the sectors missing from the rbio and
2772 * read them from the disk. If sector_in_rbio() finds a sector
2773 * in the bio list we don't need to read it off the stripe.
2774 */
2775 sector = sector_in_rbio(rbio, stripe, sectornr, 1);
2776 if (sector)
2777 continue;
2778
2779 sector = rbio_stripe_sector(rbio, stripe, sectornr);
2780 /*
2781 * The bio cache may have handed us an uptodate sector. If so,
2782 * use it.
2783 */
2784 if (sector->uptodate)
2785 continue;
2786
2787 ret = rbio_add_io_sector(rbio, &bio_list, sector, stripe,
2788 sectornr, REQ_OP_READ);
2789 if (ret) {
2790 bio_list_put(&bio_list);
2791 return ret;
2792 }
2793 }
2794
2795 submit_read_wait_bio_list(rbio, &bio_list);
2796 return 0;
2797}
2798
2799static void scrub_rbio(struct btrfs_raid_bio *rbio)
2800{
2801 int sector_nr;
2802 int ret;
2803
2804 ret = alloc_rbio_essential_pages(rbio);
2805 if (ret)
2806 goto out;
2807
2808 bitmap_clear(rbio->error_bitmap, 0, rbio->nr_sectors);
2809
2810 ret = scrub_assemble_read_bios(rbio);
2811 if (ret < 0)
2812 goto out;
2813
2814 /* We may have some failures, recover the failed sectors first. */
2815 ret = recover_scrub_rbio(rbio);
2816 if (ret < 0)
2817 goto out;
2818
2819 /*
2820 * We have every sector properly prepared. Can finish the scrub
2821 * and writeback the good content.
2822 */
2823 ret = finish_parity_scrub(rbio);
2824 wait_event(rbio->io_wait, atomic_read(&rbio->stripes_pending) == 0);
2825 for (sector_nr = 0; sector_nr < rbio->stripe_nsectors; sector_nr++) {
2826 int found_errors;
2827
2828 found_errors = get_rbio_veritical_errors(rbio, sector_nr, NULL, NULL);
2829 if (found_errors > rbio->bioc->max_errors) {
2830 ret = -EIO;
2831 break;
2832 }
2833 }
2834out:
2835 rbio_orig_end_io(rbio, errno_to_blk_status(ret));
2836}
2837
2838static void scrub_rbio_work_locked(struct work_struct *work)
2839{
2840 scrub_rbio(container_of(work, struct btrfs_raid_bio, work));
2841}
2842
2843void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio)
2844{
2845 if (!lock_stripe_add(rbio))
2846 start_async_work(rbio, scrub_rbio_work_locked);
2847}
2848
2849/*
2850 * This is for scrub call sites where we already have correct data contents.
2851 * This allows us to avoid reading data stripes again.
2852 *
2853 * Unfortunately here we have to do page copy, other than reusing the pages.
2854 * This is due to the fact rbio has its own page management for its cache.
2855 */
2856void raid56_parity_cache_data_pages(struct btrfs_raid_bio *rbio,
2857 struct page **data_pages, u64 data_logical)
2858{
2859 const u64 offset_in_full_stripe = data_logical -
2860 rbio->bioc->full_stripe_logical;
2861 const int page_index = offset_in_full_stripe >> PAGE_SHIFT;
2862 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
2863 const u32 sectors_per_page = PAGE_SIZE / sectorsize;
2864 int ret;
2865
2866 /*
2867 * If we hit ENOMEM temporarily, but later at
2868 * raid56_parity_submit_scrub_rbio() time it succeeded, we just do
2869 * the extra read, not a big deal.
2870 *
2871 * If we hit ENOMEM later at raid56_parity_submit_scrub_rbio() time,
2872 * the bio would got proper error number set.
2873 */
2874 ret = alloc_rbio_data_pages(rbio);
2875 if (ret < 0)
2876 return;
2877
2878 /* data_logical must be at stripe boundary and inside the full stripe. */
2879 ASSERT(IS_ALIGNED(offset_in_full_stripe, BTRFS_STRIPE_LEN));
2880 ASSERT(offset_in_full_stripe < (rbio->nr_data << BTRFS_STRIPE_LEN_SHIFT));
2881
2882 for (int page_nr = 0; page_nr < (BTRFS_STRIPE_LEN >> PAGE_SHIFT); page_nr++) {
2883 struct page *dst = rbio->stripe_pages[page_nr + page_index];
2884 struct page *src = data_pages[page_nr];
2885
2886 memcpy_page(dst, 0, src, 0, PAGE_SIZE);
2887 for (int sector_nr = sectors_per_page * page_index;
2888 sector_nr < sectors_per_page * (page_index + 1);
2889 sector_nr++)
2890 rbio->stripe_sectors[sector_nr].uptodate = true;
2891 }
2892}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2012 Fusion-io All rights reserved.
4 * Copyright (C) 2012 Intel Corp. All rights reserved.
5 */
6
7#include <linux/sched.h>
8#include <linux/bio.h>
9#include <linux/slab.h>
10#include <linux/blkdev.h>
11#include <linux/raid/pq.h>
12#include <linux/hash.h>
13#include <linux/list_sort.h>
14#include <linux/raid/xor.h>
15#include <linux/mm.h>
16#include "messages.h"
17#include "misc.h"
18#include "ctree.h"
19#include "disk-io.h"
20#include "volumes.h"
21#include "raid56.h"
22#include "async-thread.h"
23#include "file-item.h"
24#include "btrfs_inode.h"
25
26/* set when additional merges to this rbio are not allowed */
27#define RBIO_RMW_LOCKED_BIT 1
28
29/*
30 * set when this rbio is sitting in the hash, but it is just a cache
31 * of past RMW
32 */
33#define RBIO_CACHE_BIT 2
34
35/*
36 * set when it is safe to trust the stripe_pages for caching
37 */
38#define RBIO_CACHE_READY_BIT 3
39
40#define RBIO_CACHE_SIZE 1024
41
42#define BTRFS_STRIPE_HASH_TABLE_BITS 11
43
44/* Used by the raid56 code to lock stripes for read/modify/write */
45struct btrfs_stripe_hash {
46 struct list_head hash_list;
47 spinlock_t lock;
48};
49
50/* Used by the raid56 code to lock stripes for read/modify/write */
51struct btrfs_stripe_hash_table {
52 struct list_head stripe_cache;
53 spinlock_t cache_lock;
54 int cache_size;
55 struct btrfs_stripe_hash table[];
56};
57
58/*
59 * A bvec like structure to present a sector inside a page.
60 *
61 * Unlike bvec we don't need bvlen, as it's fixed to sectorsize.
62 */
63struct sector_ptr {
64 struct page *page;
65 unsigned int pgoff:24;
66 unsigned int uptodate:8;
67};
68
69static void rmw_rbio_work(struct work_struct *work);
70static void rmw_rbio_work_locked(struct work_struct *work);
71static void index_rbio_pages(struct btrfs_raid_bio *rbio);
72static int alloc_rbio_pages(struct btrfs_raid_bio *rbio);
73
74static int finish_parity_scrub(struct btrfs_raid_bio *rbio);
75static void scrub_rbio_work_locked(struct work_struct *work);
76
77static void free_raid_bio_pointers(struct btrfs_raid_bio *rbio)
78{
79 bitmap_free(rbio->error_bitmap);
80 kfree(rbio->stripe_pages);
81 kfree(rbio->bio_sectors);
82 kfree(rbio->stripe_sectors);
83 kfree(rbio->finish_pointers);
84}
85
86static void free_raid_bio(struct btrfs_raid_bio *rbio)
87{
88 int i;
89
90 if (!refcount_dec_and_test(&rbio->refs))
91 return;
92
93 WARN_ON(!list_empty(&rbio->stripe_cache));
94 WARN_ON(!list_empty(&rbio->hash_list));
95 WARN_ON(!bio_list_empty(&rbio->bio_list));
96
97 for (i = 0; i < rbio->nr_pages; i++) {
98 if (rbio->stripe_pages[i]) {
99 __free_page(rbio->stripe_pages[i]);
100 rbio->stripe_pages[i] = NULL;
101 }
102 }
103
104 btrfs_put_bioc(rbio->bioc);
105 free_raid_bio_pointers(rbio);
106 kfree(rbio);
107}
108
109static void start_async_work(struct btrfs_raid_bio *rbio, work_func_t work_func)
110{
111 INIT_WORK(&rbio->work, work_func);
112 queue_work(rbio->bioc->fs_info->rmw_workers, &rbio->work);
113}
114
115/*
116 * the stripe hash table is used for locking, and to collect
117 * bios in hopes of making a full stripe
118 */
119int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info)
120{
121 struct btrfs_stripe_hash_table *table;
122 struct btrfs_stripe_hash_table *x;
123 struct btrfs_stripe_hash *cur;
124 struct btrfs_stripe_hash *h;
125 int num_entries = 1 << BTRFS_STRIPE_HASH_TABLE_BITS;
126 int i;
127
128 if (info->stripe_hash_table)
129 return 0;
130
131 /*
132 * The table is large, starting with order 4 and can go as high as
133 * order 7 in case lock debugging is turned on.
134 *
135 * Try harder to allocate and fallback to vmalloc to lower the chance
136 * of a failing mount.
137 */
138 table = kvzalloc(struct_size(table, table, num_entries), GFP_KERNEL);
139 if (!table)
140 return -ENOMEM;
141
142 spin_lock_init(&table->cache_lock);
143 INIT_LIST_HEAD(&table->stripe_cache);
144
145 h = table->table;
146
147 for (i = 0; i < num_entries; i++) {
148 cur = h + i;
149 INIT_LIST_HEAD(&cur->hash_list);
150 spin_lock_init(&cur->lock);
151 }
152
153 x = cmpxchg(&info->stripe_hash_table, NULL, table);
154 kvfree(x);
155 return 0;
156}
157
158/*
159 * caching an rbio means to copy anything from the
160 * bio_sectors array into the stripe_pages array. We
161 * use the page uptodate bit in the stripe cache array
162 * to indicate if it has valid data
163 *
164 * once the caching is done, we set the cache ready
165 * bit.
166 */
167static void cache_rbio_pages(struct btrfs_raid_bio *rbio)
168{
169 int i;
170 int ret;
171
172 ret = alloc_rbio_pages(rbio);
173 if (ret)
174 return;
175
176 for (i = 0; i < rbio->nr_sectors; i++) {
177 /* Some range not covered by bio (partial write), skip it */
178 if (!rbio->bio_sectors[i].page) {
179 /*
180 * Even if the sector is not covered by bio, if it is
181 * a data sector it should still be uptodate as it is
182 * read from disk.
183 */
184 if (i < rbio->nr_data * rbio->stripe_nsectors)
185 ASSERT(rbio->stripe_sectors[i].uptodate);
186 continue;
187 }
188
189 ASSERT(rbio->stripe_sectors[i].page);
190 memcpy_page(rbio->stripe_sectors[i].page,
191 rbio->stripe_sectors[i].pgoff,
192 rbio->bio_sectors[i].page,
193 rbio->bio_sectors[i].pgoff,
194 rbio->bioc->fs_info->sectorsize);
195 rbio->stripe_sectors[i].uptodate = 1;
196 }
197 set_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
198}
199
200/*
201 * we hash on the first logical address of the stripe
202 */
203static int rbio_bucket(struct btrfs_raid_bio *rbio)
204{
205 u64 num = rbio->bioc->full_stripe_logical;
206
207 /*
208 * we shift down quite a bit. We're using byte
209 * addressing, and most of the lower bits are zeros.
210 * This tends to upset hash_64, and it consistently
211 * returns just one or two different values.
212 *
213 * shifting off the lower bits fixes things.
214 */
215 return hash_64(num >> 16, BTRFS_STRIPE_HASH_TABLE_BITS);
216}
217
218static bool full_page_sectors_uptodate(struct btrfs_raid_bio *rbio,
219 unsigned int page_nr)
220{
221 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
222 const u32 sectors_per_page = PAGE_SIZE / sectorsize;
223 int i;
224
225 ASSERT(page_nr < rbio->nr_pages);
226
227 for (i = sectors_per_page * page_nr;
228 i < sectors_per_page * page_nr + sectors_per_page;
229 i++) {
230 if (!rbio->stripe_sectors[i].uptodate)
231 return false;
232 }
233 return true;
234}
235
236/*
237 * Update the stripe_sectors[] array to use correct page and pgoff
238 *
239 * Should be called every time any page pointer in stripes_pages[] got modified.
240 */
241static void index_stripe_sectors(struct btrfs_raid_bio *rbio)
242{
243 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
244 u32 offset;
245 int i;
246
247 for (i = 0, offset = 0; i < rbio->nr_sectors; i++, offset += sectorsize) {
248 int page_index = offset >> PAGE_SHIFT;
249
250 ASSERT(page_index < rbio->nr_pages);
251 rbio->stripe_sectors[i].page = rbio->stripe_pages[page_index];
252 rbio->stripe_sectors[i].pgoff = offset_in_page(offset);
253 }
254}
255
256static void steal_rbio_page(struct btrfs_raid_bio *src,
257 struct btrfs_raid_bio *dest, int page_nr)
258{
259 const u32 sectorsize = src->bioc->fs_info->sectorsize;
260 const u32 sectors_per_page = PAGE_SIZE / sectorsize;
261 int i;
262
263 if (dest->stripe_pages[page_nr])
264 __free_page(dest->stripe_pages[page_nr]);
265 dest->stripe_pages[page_nr] = src->stripe_pages[page_nr];
266 src->stripe_pages[page_nr] = NULL;
267
268 /* Also update the sector->uptodate bits. */
269 for (i = sectors_per_page * page_nr;
270 i < sectors_per_page * page_nr + sectors_per_page; i++)
271 dest->stripe_sectors[i].uptodate = true;
272}
273
274static bool is_data_stripe_page(struct btrfs_raid_bio *rbio, int page_nr)
275{
276 const int sector_nr = (page_nr << PAGE_SHIFT) >>
277 rbio->bioc->fs_info->sectorsize_bits;
278
279 /*
280 * We have ensured PAGE_SIZE is aligned with sectorsize, thus
281 * we won't have a page which is half data half parity.
282 *
283 * Thus if the first sector of the page belongs to data stripes, then
284 * the full page belongs to data stripes.
285 */
286 return (sector_nr < rbio->nr_data * rbio->stripe_nsectors);
287}
288
289/*
290 * Stealing an rbio means taking all the uptodate pages from the stripe array
291 * in the source rbio and putting them into the destination rbio.
292 *
293 * This will also update the involved stripe_sectors[] which are referring to
294 * the old pages.
295 */
296static void steal_rbio(struct btrfs_raid_bio *src, struct btrfs_raid_bio *dest)
297{
298 int i;
299
300 if (!test_bit(RBIO_CACHE_READY_BIT, &src->flags))
301 return;
302
303 for (i = 0; i < dest->nr_pages; i++) {
304 struct page *p = src->stripe_pages[i];
305
306 /*
307 * We don't need to steal P/Q pages as they will always be
308 * regenerated for RMW or full write anyway.
309 */
310 if (!is_data_stripe_page(src, i))
311 continue;
312
313 /*
314 * If @src already has RBIO_CACHE_READY_BIT, it should have
315 * all data stripe pages present and uptodate.
316 */
317 ASSERT(p);
318 ASSERT(full_page_sectors_uptodate(src, i));
319 steal_rbio_page(src, dest, i);
320 }
321 index_stripe_sectors(dest);
322 index_stripe_sectors(src);
323}
324
325/*
326 * merging means we take the bio_list from the victim and
327 * splice it into the destination. The victim should
328 * be discarded afterwards.
329 *
330 * must be called with dest->rbio_list_lock held
331 */
332static void merge_rbio(struct btrfs_raid_bio *dest,
333 struct btrfs_raid_bio *victim)
334{
335 bio_list_merge(&dest->bio_list, &victim->bio_list);
336 dest->bio_list_bytes += victim->bio_list_bytes;
337 /* Also inherit the bitmaps from @victim. */
338 bitmap_or(&dest->dbitmap, &victim->dbitmap, &dest->dbitmap,
339 dest->stripe_nsectors);
340 bio_list_init(&victim->bio_list);
341}
342
343/*
344 * used to prune items that are in the cache. The caller
345 * must hold the hash table lock.
346 */
347static void __remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
348{
349 int bucket = rbio_bucket(rbio);
350 struct btrfs_stripe_hash_table *table;
351 struct btrfs_stripe_hash *h;
352 int freeit = 0;
353
354 /*
355 * check the bit again under the hash table lock.
356 */
357 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
358 return;
359
360 table = rbio->bioc->fs_info->stripe_hash_table;
361 h = table->table + bucket;
362
363 /* hold the lock for the bucket because we may be
364 * removing it from the hash table
365 */
366 spin_lock(&h->lock);
367
368 /*
369 * hold the lock for the bio list because we need
370 * to make sure the bio list is empty
371 */
372 spin_lock(&rbio->bio_list_lock);
373
374 if (test_and_clear_bit(RBIO_CACHE_BIT, &rbio->flags)) {
375 list_del_init(&rbio->stripe_cache);
376 table->cache_size -= 1;
377 freeit = 1;
378
379 /* if the bio list isn't empty, this rbio is
380 * still involved in an IO. We take it out
381 * of the cache list, and drop the ref that
382 * was held for the list.
383 *
384 * If the bio_list was empty, we also remove
385 * the rbio from the hash_table, and drop
386 * the corresponding ref
387 */
388 if (bio_list_empty(&rbio->bio_list)) {
389 if (!list_empty(&rbio->hash_list)) {
390 list_del_init(&rbio->hash_list);
391 refcount_dec(&rbio->refs);
392 BUG_ON(!list_empty(&rbio->plug_list));
393 }
394 }
395 }
396
397 spin_unlock(&rbio->bio_list_lock);
398 spin_unlock(&h->lock);
399
400 if (freeit)
401 free_raid_bio(rbio);
402}
403
404/*
405 * prune a given rbio from the cache
406 */
407static void remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
408{
409 struct btrfs_stripe_hash_table *table;
410
411 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
412 return;
413
414 table = rbio->bioc->fs_info->stripe_hash_table;
415
416 spin_lock(&table->cache_lock);
417 __remove_rbio_from_cache(rbio);
418 spin_unlock(&table->cache_lock);
419}
420
421/*
422 * remove everything in the cache
423 */
424static void btrfs_clear_rbio_cache(struct btrfs_fs_info *info)
425{
426 struct btrfs_stripe_hash_table *table;
427 struct btrfs_raid_bio *rbio;
428
429 table = info->stripe_hash_table;
430
431 spin_lock(&table->cache_lock);
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(&table->cache_lock);
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
469 if (!test_bit(RBIO_CACHE_READY_BIT, &rbio->flags))
470 return;
471
472 table = rbio->bioc->fs_info->stripe_hash_table;
473
474 spin_lock(&table->cache_lock);
475 spin_lock(&rbio->bio_list_lock);
476
477 /* bump our ref if we were not in the list before */
478 if (!test_and_set_bit(RBIO_CACHE_BIT, &rbio->flags))
479 refcount_inc(&rbio->refs);
480
481 if (!list_empty(&rbio->stripe_cache)){
482 list_move(&rbio->stripe_cache, &table->stripe_cache);
483 } else {
484 list_add(&rbio->stripe_cache, &table->stripe_cache);
485 table->cache_size += 1;
486 }
487
488 spin_unlock(&rbio->bio_list_lock);
489
490 if (table->cache_size > RBIO_CACHE_SIZE) {
491 struct btrfs_raid_bio *found;
492
493 found = list_entry(table->stripe_cache.prev,
494 struct btrfs_raid_bio,
495 stripe_cache);
496
497 if (found != rbio)
498 __remove_rbio_from_cache(found);
499 }
500
501 spin_unlock(&table->cache_lock);
502}
503
504/*
505 * helper function to run the xor_blocks api. It is only
506 * able to do MAX_XOR_BLOCKS at a time, so we need to
507 * loop through.
508 */
509static void run_xor(void **pages, int src_cnt, ssize_t len)
510{
511 int src_off = 0;
512 int xor_src_cnt = 0;
513 void *dest = pages[src_cnt];
514
515 while(src_cnt > 0) {
516 xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS);
517 xor_blocks(xor_src_cnt, len, dest, pages + src_off);
518
519 src_cnt -= xor_src_cnt;
520 src_off += xor_src_cnt;
521 }
522}
523
524/*
525 * Returns true if the bio list inside this rbio covers an entire stripe (no
526 * rmw required).
527 */
528static int rbio_is_full(struct btrfs_raid_bio *rbio)
529{
530 unsigned long size = rbio->bio_list_bytes;
531 int ret = 1;
532
533 spin_lock(&rbio->bio_list_lock);
534 if (size != rbio->nr_data * BTRFS_STRIPE_LEN)
535 ret = 0;
536 BUG_ON(size > rbio->nr_data * BTRFS_STRIPE_LEN);
537 spin_unlock(&rbio->bio_list_lock);
538
539 return ret;
540}
541
542/*
543 * returns 1 if it is safe to merge two rbios together.
544 * The merging is safe if the two rbios correspond to
545 * the same stripe and if they are both going in the same
546 * direction (read vs write), and if neither one is
547 * locked for final IO
548 *
549 * The caller is responsible for locking such that
550 * rmw_locked is safe to test
551 */
552static int rbio_can_merge(struct btrfs_raid_bio *last,
553 struct btrfs_raid_bio *cur)
554{
555 if (test_bit(RBIO_RMW_LOCKED_BIT, &last->flags) ||
556 test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags))
557 return 0;
558
559 /*
560 * we can't merge with cached rbios, since the
561 * idea is that when we merge the destination
562 * rbio is going to run our IO for us. We can
563 * steal from cached rbios though, other functions
564 * handle that.
565 */
566 if (test_bit(RBIO_CACHE_BIT, &last->flags) ||
567 test_bit(RBIO_CACHE_BIT, &cur->flags))
568 return 0;
569
570 if (last->bioc->full_stripe_logical != cur->bioc->full_stripe_logical)
571 return 0;
572
573 /* we can't merge with different operations */
574 if (last->operation != cur->operation)
575 return 0;
576 /*
577 * We've need read the full stripe from the drive.
578 * check and repair the parity and write the new results.
579 *
580 * We're not allowed to add any new bios to the
581 * bio list here, anyone else that wants to
582 * change this stripe needs to do their own rmw.
583 */
584 if (last->operation == BTRFS_RBIO_PARITY_SCRUB)
585 return 0;
586
587 if (last->operation == BTRFS_RBIO_READ_REBUILD)
588 return 0;
589
590 return 1;
591}
592
593static unsigned int rbio_stripe_sector_index(const struct btrfs_raid_bio *rbio,
594 unsigned int stripe_nr,
595 unsigned int sector_nr)
596{
597 ASSERT(stripe_nr < rbio->real_stripes);
598 ASSERT(sector_nr < rbio->stripe_nsectors);
599
600 return stripe_nr * rbio->stripe_nsectors + sector_nr;
601}
602
603/* Return a sector from rbio->stripe_sectors, not from the bio list */
604static struct sector_ptr *rbio_stripe_sector(const struct btrfs_raid_bio *rbio,
605 unsigned int stripe_nr,
606 unsigned int sector_nr)
607{
608 return &rbio->stripe_sectors[rbio_stripe_sector_index(rbio, stripe_nr,
609 sector_nr)];
610}
611
612/* Grab a sector inside P stripe */
613static struct sector_ptr *rbio_pstripe_sector(const struct btrfs_raid_bio *rbio,
614 unsigned int sector_nr)
615{
616 return rbio_stripe_sector(rbio, rbio->nr_data, sector_nr);
617}
618
619/* Grab a sector inside Q stripe, return NULL if not RAID6 */
620static struct sector_ptr *rbio_qstripe_sector(const struct btrfs_raid_bio *rbio,
621 unsigned int sector_nr)
622{
623 if (rbio->nr_data + 1 == rbio->real_stripes)
624 return NULL;
625 return rbio_stripe_sector(rbio, rbio->nr_data + 1, sector_nr);
626}
627
628/*
629 * The first stripe in the table for a logical address
630 * has the lock. rbios are added in one of three ways:
631 *
632 * 1) Nobody has the stripe locked yet. The rbio is given
633 * the lock and 0 is returned. The caller must start the IO
634 * themselves.
635 *
636 * 2) Someone has the stripe locked, but we're able to merge
637 * with the lock owner. The rbio is freed and the IO will
638 * start automatically along with the existing rbio. 1 is returned.
639 *
640 * 3) Someone has the stripe locked, but we're not able to merge.
641 * The rbio is added to the lock owner's plug list, or merged into
642 * an rbio already on the plug list. When the lock owner unlocks,
643 * the next rbio on the list is run and the IO is started automatically.
644 * 1 is returned
645 *
646 * If we return 0, the caller still owns the rbio and must continue with
647 * IO submission. If we return 1, the caller must assume the rbio has
648 * already been freed.
649 */
650static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
651{
652 struct btrfs_stripe_hash *h;
653 struct btrfs_raid_bio *cur;
654 struct btrfs_raid_bio *pending;
655 struct btrfs_raid_bio *freeit = NULL;
656 struct btrfs_raid_bio *cache_drop = NULL;
657 int ret = 0;
658
659 h = rbio->bioc->fs_info->stripe_hash_table->table + rbio_bucket(rbio);
660
661 spin_lock(&h->lock);
662 list_for_each_entry(cur, &h->hash_list, hash_list) {
663 if (cur->bioc->full_stripe_logical != rbio->bioc->full_stripe_logical)
664 continue;
665
666 spin_lock(&cur->bio_list_lock);
667
668 /* Can we steal this cached rbio's pages? */
669 if (bio_list_empty(&cur->bio_list) &&
670 list_empty(&cur->plug_list) &&
671 test_bit(RBIO_CACHE_BIT, &cur->flags) &&
672 !test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) {
673 list_del_init(&cur->hash_list);
674 refcount_dec(&cur->refs);
675
676 steal_rbio(cur, rbio);
677 cache_drop = cur;
678 spin_unlock(&cur->bio_list_lock);
679
680 goto lockit;
681 }
682
683 /* Can we merge into the lock owner? */
684 if (rbio_can_merge(cur, rbio)) {
685 merge_rbio(cur, rbio);
686 spin_unlock(&cur->bio_list_lock);
687 freeit = rbio;
688 ret = 1;
689 goto out;
690 }
691
692
693 /*
694 * We couldn't merge with the running rbio, see if we can merge
695 * with the pending ones. We don't have to check for rmw_locked
696 * because there is no way they are inside finish_rmw right now
697 */
698 list_for_each_entry(pending, &cur->plug_list, plug_list) {
699 if (rbio_can_merge(pending, rbio)) {
700 merge_rbio(pending, rbio);
701 spin_unlock(&cur->bio_list_lock);
702 freeit = rbio;
703 ret = 1;
704 goto out;
705 }
706 }
707
708 /*
709 * No merging, put us on the tail of the plug list, our rbio
710 * will be started with the currently running rbio unlocks
711 */
712 list_add_tail(&rbio->plug_list, &cur->plug_list);
713 spin_unlock(&cur->bio_list_lock);
714 ret = 1;
715 goto out;
716 }
717lockit:
718 refcount_inc(&rbio->refs);
719 list_add(&rbio->hash_list, &h->hash_list);
720out:
721 spin_unlock(&h->lock);
722 if (cache_drop)
723 remove_rbio_from_cache(cache_drop);
724 if (freeit)
725 free_raid_bio(freeit);
726 return ret;
727}
728
729static void recover_rbio_work_locked(struct work_struct *work);
730
731/*
732 * called as rmw or parity rebuild is completed. If the plug list has more
733 * rbios waiting for this stripe, the next one on the list will be started
734 */
735static noinline void unlock_stripe(struct btrfs_raid_bio *rbio)
736{
737 int bucket;
738 struct btrfs_stripe_hash *h;
739 int keep_cache = 0;
740
741 bucket = rbio_bucket(rbio);
742 h = rbio->bioc->fs_info->stripe_hash_table->table + bucket;
743
744 if (list_empty(&rbio->plug_list))
745 cache_rbio(rbio);
746
747 spin_lock(&h->lock);
748 spin_lock(&rbio->bio_list_lock);
749
750 if (!list_empty(&rbio->hash_list)) {
751 /*
752 * if we're still cached and there is no other IO
753 * to perform, just leave this rbio here for others
754 * to steal from later
755 */
756 if (list_empty(&rbio->plug_list) &&
757 test_bit(RBIO_CACHE_BIT, &rbio->flags)) {
758 keep_cache = 1;
759 clear_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
760 BUG_ON(!bio_list_empty(&rbio->bio_list));
761 goto done;
762 }
763
764 list_del_init(&rbio->hash_list);
765 refcount_dec(&rbio->refs);
766
767 /*
768 * we use the plug list to hold all the rbios
769 * waiting for the chance to lock this stripe.
770 * hand the lock over to one of them.
771 */
772 if (!list_empty(&rbio->plug_list)) {
773 struct btrfs_raid_bio *next;
774 struct list_head *head = rbio->plug_list.next;
775
776 next = list_entry(head, struct btrfs_raid_bio,
777 plug_list);
778
779 list_del_init(&rbio->plug_list);
780
781 list_add(&next->hash_list, &h->hash_list);
782 refcount_inc(&next->refs);
783 spin_unlock(&rbio->bio_list_lock);
784 spin_unlock(&h->lock);
785
786 if (next->operation == BTRFS_RBIO_READ_REBUILD) {
787 start_async_work(next, recover_rbio_work_locked);
788 } else if (next->operation == BTRFS_RBIO_WRITE) {
789 steal_rbio(rbio, next);
790 start_async_work(next, rmw_rbio_work_locked);
791 } else if (next->operation == BTRFS_RBIO_PARITY_SCRUB) {
792 steal_rbio(rbio, next);
793 start_async_work(next, scrub_rbio_work_locked);
794 }
795
796 goto done_nolock;
797 }
798 }
799done:
800 spin_unlock(&rbio->bio_list_lock);
801 spin_unlock(&h->lock);
802
803done_nolock:
804 if (!keep_cache)
805 remove_rbio_from_cache(rbio);
806}
807
808static void rbio_endio_bio_list(struct bio *cur, blk_status_t err)
809{
810 struct bio *next;
811
812 while (cur) {
813 next = cur->bi_next;
814 cur->bi_next = NULL;
815 cur->bi_status = err;
816 bio_endio(cur);
817 cur = next;
818 }
819}
820
821/*
822 * this frees the rbio and runs through all the bios in the
823 * bio_list and calls end_io on them
824 */
825static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, blk_status_t err)
826{
827 struct bio *cur = bio_list_get(&rbio->bio_list);
828 struct bio *extra;
829
830 kfree(rbio->csum_buf);
831 bitmap_free(rbio->csum_bitmap);
832 rbio->csum_buf = NULL;
833 rbio->csum_bitmap = NULL;
834
835 /*
836 * Clear the data bitmap, as the rbio may be cached for later usage.
837 * do this before before unlock_stripe() so there will be no new bio
838 * for this bio.
839 */
840 bitmap_clear(&rbio->dbitmap, 0, rbio->stripe_nsectors);
841
842 /*
843 * At this moment, rbio->bio_list is empty, however since rbio does not
844 * always have RBIO_RMW_LOCKED_BIT set and rbio is still linked on the
845 * hash list, rbio may be merged with others so that rbio->bio_list
846 * becomes non-empty.
847 * Once unlock_stripe() is done, rbio->bio_list will not be updated any
848 * more and we can call bio_endio() on all queued bios.
849 */
850 unlock_stripe(rbio);
851 extra = bio_list_get(&rbio->bio_list);
852 free_raid_bio(rbio);
853
854 rbio_endio_bio_list(cur, err);
855 if (extra)
856 rbio_endio_bio_list(extra, err);
857}
858
859/*
860 * Get a sector pointer specified by its @stripe_nr and @sector_nr.
861 *
862 * @rbio: The raid bio
863 * @stripe_nr: Stripe number, valid range [0, real_stripe)
864 * @sector_nr: Sector number inside the stripe,
865 * valid range [0, stripe_nsectors)
866 * @bio_list_only: Whether to use sectors inside the bio list only.
867 *
868 * The read/modify/write code wants to reuse the original bio page as much
869 * as possible, and only use stripe_sectors as fallback.
870 */
871static struct sector_ptr *sector_in_rbio(struct btrfs_raid_bio *rbio,
872 int stripe_nr, int sector_nr,
873 bool bio_list_only)
874{
875 struct sector_ptr *sector;
876 int index;
877
878 ASSERT(stripe_nr >= 0 && stripe_nr < rbio->real_stripes);
879 ASSERT(sector_nr >= 0 && sector_nr < rbio->stripe_nsectors);
880
881 index = stripe_nr * rbio->stripe_nsectors + sector_nr;
882 ASSERT(index >= 0 && index < rbio->nr_sectors);
883
884 spin_lock(&rbio->bio_list_lock);
885 sector = &rbio->bio_sectors[index];
886 if (sector->page || bio_list_only) {
887 /* Don't return sector without a valid page pointer */
888 if (!sector->page)
889 sector = NULL;
890 spin_unlock(&rbio->bio_list_lock);
891 return sector;
892 }
893 spin_unlock(&rbio->bio_list_lock);
894
895 return &rbio->stripe_sectors[index];
896}
897
898/*
899 * allocation and initial setup for the btrfs_raid_bio. Not
900 * this does not allocate any pages for rbio->pages.
901 */
902static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info,
903 struct btrfs_io_context *bioc)
904{
905 const unsigned int real_stripes = bioc->num_stripes - bioc->replace_nr_stripes;
906 const unsigned int stripe_npages = BTRFS_STRIPE_LEN >> PAGE_SHIFT;
907 const unsigned int num_pages = stripe_npages * real_stripes;
908 const unsigned int stripe_nsectors =
909 BTRFS_STRIPE_LEN >> fs_info->sectorsize_bits;
910 const unsigned int num_sectors = stripe_nsectors * real_stripes;
911 struct btrfs_raid_bio *rbio;
912
913 /* PAGE_SIZE must also be aligned to sectorsize for subpage support */
914 ASSERT(IS_ALIGNED(PAGE_SIZE, fs_info->sectorsize));
915 /*
916 * Our current stripe len should be fixed to 64k thus stripe_nsectors
917 * (at most 16) should be no larger than BITS_PER_LONG.
918 */
919 ASSERT(stripe_nsectors <= BITS_PER_LONG);
920
921 rbio = kzalloc(sizeof(*rbio), GFP_NOFS);
922 if (!rbio)
923 return ERR_PTR(-ENOMEM);
924 rbio->stripe_pages = kcalloc(num_pages, sizeof(struct page *),
925 GFP_NOFS);
926 rbio->bio_sectors = kcalloc(num_sectors, sizeof(struct sector_ptr),
927 GFP_NOFS);
928 rbio->stripe_sectors = kcalloc(num_sectors, sizeof(struct sector_ptr),
929 GFP_NOFS);
930 rbio->finish_pointers = kcalloc(real_stripes, sizeof(void *), GFP_NOFS);
931 rbio->error_bitmap = bitmap_zalloc(num_sectors, GFP_NOFS);
932
933 if (!rbio->stripe_pages || !rbio->bio_sectors || !rbio->stripe_sectors ||
934 !rbio->finish_pointers || !rbio->error_bitmap) {
935 free_raid_bio_pointers(rbio);
936 kfree(rbio);
937 return ERR_PTR(-ENOMEM);
938 }
939
940 bio_list_init(&rbio->bio_list);
941 init_waitqueue_head(&rbio->io_wait);
942 INIT_LIST_HEAD(&rbio->plug_list);
943 spin_lock_init(&rbio->bio_list_lock);
944 INIT_LIST_HEAD(&rbio->stripe_cache);
945 INIT_LIST_HEAD(&rbio->hash_list);
946 btrfs_get_bioc(bioc);
947 rbio->bioc = bioc;
948 rbio->nr_pages = num_pages;
949 rbio->nr_sectors = num_sectors;
950 rbio->real_stripes = real_stripes;
951 rbio->stripe_npages = stripe_npages;
952 rbio->stripe_nsectors = stripe_nsectors;
953 refcount_set(&rbio->refs, 1);
954 atomic_set(&rbio->stripes_pending, 0);
955
956 ASSERT(btrfs_nr_parity_stripes(bioc->map_type));
957 rbio->nr_data = real_stripes - btrfs_nr_parity_stripes(bioc->map_type);
958
959 return rbio;
960}
961
962/* allocate pages for all the stripes in the bio, including parity */
963static int alloc_rbio_pages(struct btrfs_raid_bio *rbio)
964{
965 int ret;
966
967 ret = btrfs_alloc_page_array(rbio->nr_pages, rbio->stripe_pages, 0);
968 if (ret < 0)
969 return ret;
970 /* Mapping all sectors */
971 index_stripe_sectors(rbio);
972 return 0;
973}
974
975/* only allocate pages for p/q stripes */
976static int alloc_rbio_parity_pages(struct btrfs_raid_bio *rbio)
977{
978 const int data_pages = rbio->nr_data * rbio->stripe_npages;
979 int ret;
980
981 ret = btrfs_alloc_page_array(rbio->nr_pages - data_pages,
982 rbio->stripe_pages + data_pages, 0);
983 if (ret < 0)
984 return ret;
985
986 index_stripe_sectors(rbio);
987 return 0;
988}
989
990/*
991 * Return the total number of errors found in the vertical stripe of @sector_nr.
992 *
993 * @faila and @failb will also be updated to the first and second stripe
994 * number of the errors.
995 */
996static int get_rbio_veritical_errors(struct btrfs_raid_bio *rbio, int sector_nr,
997 int *faila, int *failb)
998{
999 int stripe_nr;
1000 int found_errors = 0;
1001
1002 if (faila || failb) {
1003 /*
1004 * Both @faila and @failb should be valid pointers if any of
1005 * them is specified.
1006 */
1007 ASSERT(faila && failb);
1008 *faila = -1;
1009 *failb = -1;
1010 }
1011
1012 for (stripe_nr = 0; stripe_nr < rbio->real_stripes; stripe_nr++) {
1013 int total_sector_nr = stripe_nr * rbio->stripe_nsectors + sector_nr;
1014
1015 if (test_bit(total_sector_nr, rbio->error_bitmap)) {
1016 found_errors++;
1017 if (faila) {
1018 /* Update faila and failb. */
1019 if (*faila < 0)
1020 *faila = stripe_nr;
1021 else if (*failb < 0)
1022 *failb = stripe_nr;
1023 }
1024 }
1025 }
1026 return found_errors;
1027}
1028
1029/*
1030 * Add a single sector @sector into our list of bios for IO.
1031 *
1032 * Return 0 if everything went well.
1033 * Return <0 for error.
1034 */
1035static int rbio_add_io_sector(struct btrfs_raid_bio *rbio,
1036 struct bio_list *bio_list,
1037 struct sector_ptr *sector,
1038 unsigned int stripe_nr,
1039 unsigned int sector_nr,
1040 enum req_op op)
1041{
1042 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
1043 struct bio *last = bio_list->tail;
1044 int ret;
1045 struct bio *bio;
1046 struct btrfs_io_stripe *stripe;
1047 u64 disk_start;
1048
1049 /*
1050 * Note: here stripe_nr has taken device replace into consideration,
1051 * thus it can be larger than rbio->real_stripe.
1052 * So here we check against bioc->num_stripes, not rbio->real_stripes.
1053 */
1054 ASSERT(stripe_nr >= 0 && stripe_nr < rbio->bioc->num_stripes);
1055 ASSERT(sector_nr >= 0 && sector_nr < rbio->stripe_nsectors);
1056 ASSERT(sector->page);
1057
1058 stripe = &rbio->bioc->stripes[stripe_nr];
1059 disk_start = stripe->physical + sector_nr * sectorsize;
1060
1061 /* if the device is missing, just fail this stripe */
1062 if (!stripe->dev->bdev) {
1063 int found_errors;
1064
1065 set_bit(stripe_nr * rbio->stripe_nsectors + sector_nr,
1066 rbio->error_bitmap);
1067
1068 /* Check if we have reached tolerance early. */
1069 found_errors = get_rbio_veritical_errors(rbio, sector_nr,
1070 NULL, NULL);
1071 if (found_errors > rbio->bioc->max_errors)
1072 return -EIO;
1073 return 0;
1074 }
1075
1076 /* see if we can add this page onto our existing bio */
1077 if (last) {
1078 u64 last_end = last->bi_iter.bi_sector << SECTOR_SHIFT;
1079 last_end += last->bi_iter.bi_size;
1080
1081 /*
1082 * we can't merge these if they are from different
1083 * devices or if they are not contiguous
1084 */
1085 if (last_end == disk_start && !last->bi_status &&
1086 last->bi_bdev == stripe->dev->bdev) {
1087 ret = bio_add_page(last, sector->page, sectorsize,
1088 sector->pgoff);
1089 if (ret == sectorsize)
1090 return 0;
1091 }
1092 }
1093
1094 /* put a new bio on the list */
1095 bio = bio_alloc(stripe->dev->bdev,
1096 max(BTRFS_STRIPE_LEN >> PAGE_SHIFT, 1),
1097 op, GFP_NOFS);
1098 bio->bi_iter.bi_sector = disk_start >> SECTOR_SHIFT;
1099 bio->bi_private = rbio;
1100
1101 __bio_add_page(bio, sector->page, sectorsize, sector->pgoff);
1102 bio_list_add(bio_list, bio);
1103 return 0;
1104}
1105
1106static void index_one_bio(struct btrfs_raid_bio *rbio, struct bio *bio)
1107{
1108 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
1109 struct bio_vec bvec;
1110 struct bvec_iter iter;
1111 u32 offset = (bio->bi_iter.bi_sector << SECTOR_SHIFT) -
1112 rbio->bioc->full_stripe_logical;
1113
1114 bio_for_each_segment(bvec, bio, iter) {
1115 u32 bvec_offset;
1116
1117 for (bvec_offset = 0; bvec_offset < bvec.bv_len;
1118 bvec_offset += sectorsize, offset += sectorsize) {
1119 int index = offset / sectorsize;
1120 struct sector_ptr *sector = &rbio->bio_sectors[index];
1121
1122 sector->page = bvec.bv_page;
1123 sector->pgoff = bvec.bv_offset + bvec_offset;
1124 ASSERT(sector->pgoff < PAGE_SIZE);
1125 }
1126 }
1127}
1128
1129/*
1130 * helper function to walk our bio list and populate the bio_pages array with
1131 * the result. This seems expensive, but it is faster than constantly
1132 * searching through the bio list as we setup the IO in finish_rmw or stripe
1133 * reconstruction.
1134 *
1135 * This must be called before you trust the answers from page_in_rbio
1136 */
1137static void index_rbio_pages(struct btrfs_raid_bio *rbio)
1138{
1139 struct bio *bio;
1140
1141 spin_lock(&rbio->bio_list_lock);
1142 bio_list_for_each(bio, &rbio->bio_list)
1143 index_one_bio(rbio, bio);
1144
1145 spin_unlock(&rbio->bio_list_lock);
1146}
1147
1148static void bio_get_trace_info(struct btrfs_raid_bio *rbio, struct bio *bio,
1149 struct raid56_bio_trace_info *trace_info)
1150{
1151 const struct btrfs_io_context *bioc = rbio->bioc;
1152 int i;
1153
1154 ASSERT(bioc);
1155
1156 /* We rely on bio->bi_bdev to find the stripe number. */
1157 if (!bio->bi_bdev)
1158 goto not_found;
1159
1160 for (i = 0; i < bioc->num_stripes; i++) {
1161 if (bio->bi_bdev != bioc->stripes[i].dev->bdev)
1162 continue;
1163 trace_info->stripe_nr = i;
1164 trace_info->devid = bioc->stripes[i].dev->devid;
1165 trace_info->offset = (bio->bi_iter.bi_sector << SECTOR_SHIFT) -
1166 bioc->stripes[i].physical;
1167 return;
1168 }
1169
1170not_found:
1171 trace_info->devid = -1;
1172 trace_info->offset = -1;
1173 trace_info->stripe_nr = -1;
1174}
1175
1176static inline void bio_list_put(struct bio_list *bio_list)
1177{
1178 struct bio *bio;
1179
1180 while ((bio = bio_list_pop(bio_list)))
1181 bio_put(bio);
1182}
1183
1184/* Generate PQ for one vertical stripe. */
1185static void generate_pq_vertical(struct btrfs_raid_bio *rbio, int sectornr)
1186{
1187 void **pointers = rbio->finish_pointers;
1188 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
1189 struct sector_ptr *sector;
1190 int stripe;
1191 const bool has_qstripe = rbio->bioc->map_type & BTRFS_BLOCK_GROUP_RAID6;
1192
1193 /* First collect one sector from each data stripe */
1194 for (stripe = 0; stripe < rbio->nr_data; stripe++) {
1195 sector = sector_in_rbio(rbio, stripe, sectornr, 0);
1196 pointers[stripe] = kmap_local_page(sector->page) +
1197 sector->pgoff;
1198 }
1199
1200 /* Then add the parity stripe */
1201 sector = rbio_pstripe_sector(rbio, sectornr);
1202 sector->uptodate = 1;
1203 pointers[stripe++] = kmap_local_page(sector->page) + sector->pgoff;
1204
1205 if (has_qstripe) {
1206 /*
1207 * RAID6, add the qstripe and call the library function
1208 * to fill in our p/q
1209 */
1210 sector = rbio_qstripe_sector(rbio, sectornr);
1211 sector->uptodate = 1;
1212 pointers[stripe++] = kmap_local_page(sector->page) +
1213 sector->pgoff;
1214
1215 raid6_call.gen_syndrome(rbio->real_stripes, sectorsize,
1216 pointers);
1217 } else {
1218 /* raid5 */
1219 memcpy(pointers[rbio->nr_data], pointers[0], sectorsize);
1220 run_xor(pointers + 1, rbio->nr_data - 1, sectorsize);
1221 }
1222 for (stripe = stripe - 1; stripe >= 0; stripe--)
1223 kunmap_local(pointers[stripe]);
1224}
1225
1226static int rmw_assemble_write_bios(struct btrfs_raid_bio *rbio,
1227 struct bio_list *bio_list)
1228{
1229 /* The total sector number inside the full stripe. */
1230 int total_sector_nr;
1231 int sectornr;
1232 int stripe;
1233 int ret;
1234
1235 ASSERT(bio_list_size(bio_list) == 0);
1236
1237 /* We should have at least one data sector. */
1238 ASSERT(bitmap_weight(&rbio->dbitmap, rbio->stripe_nsectors));
1239
1240 /*
1241 * Reset errors, as we may have errors inherited from from degraded
1242 * write.
1243 */
1244 bitmap_clear(rbio->error_bitmap, 0, rbio->nr_sectors);
1245
1246 /*
1247 * Start assembly. Make bios for everything from the higher layers (the
1248 * bio_list in our rbio) and our P/Q. Ignore everything else.
1249 */
1250 for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
1251 total_sector_nr++) {
1252 struct sector_ptr *sector;
1253
1254 stripe = total_sector_nr / rbio->stripe_nsectors;
1255 sectornr = total_sector_nr % rbio->stripe_nsectors;
1256
1257 /* This vertical stripe has no data, skip it. */
1258 if (!test_bit(sectornr, &rbio->dbitmap))
1259 continue;
1260
1261 if (stripe < rbio->nr_data) {
1262 sector = sector_in_rbio(rbio, stripe, sectornr, 1);
1263 if (!sector)
1264 continue;
1265 } else {
1266 sector = rbio_stripe_sector(rbio, stripe, sectornr);
1267 }
1268
1269 ret = rbio_add_io_sector(rbio, bio_list, sector, stripe,
1270 sectornr, REQ_OP_WRITE);
1271 if (ret)
1272 goto error;
1273 }
1274
1275 if (likely(!rbio->bioc->replace_nr_stripes))
1276 return 0;
1277
1278 /*
1279 * Make a copy for the replace target device.
1280 *
1281 * Thus the source stripe number (in replace_stripe_src) should be valid.
1282 */
1283 ASSERT(rbio->bioc->replace_stripe_src >= 0);
1284
1285 for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
1286 total_sector_nr++) {
1287 struct sector_ptr *sector;
1288
1289 stripe = total_sector_nr / rbio->stripe_nsectors;
1290 sectornr = total_sector_nr % rbio->stripe_nsectors;
1291
1292 /*
1293 * For RAID56, there is only one device that can be replaced,
1294 * and replace_stripe_src[0] indicates the stripe number we
1295 * need to copy from.
1296 */
1297 if (stripe != rbio->bioc->replace_stripe_src) {
1298 /*
1299 * We can skip the whole stripe completely, note
1300 * total_sector_nr will be increased by one anyway.
1301 */
1302 ASSERT(sectornr == 0);
1303 total_sector_nr += rbio->stripe_nsectors - 1;
1304 continue;
1305 }
1306
1307 /* This vertical stripe has no data, skip it. */
1308 if (!test_bit(sectornr, &rbio->dbitmap))
1309 continue;
1310
1311 if (stripe < rbio->nr_data) {
1312 sector = sector_in_rbio(rbio, stripe, sectornr, 1);
1313 if (!sector)
1314 continue;
1315 } else {
1316 sector = rbio_stripe_sector(rbio, stripe, sectornr);
1317 }
1318
1319 ret = rbio_add_io_sector(rbio, bio_list, sector,
1320 rbio->real_stripes,
1321 sectornr, REQ_OP_WRITE);
1322 if (ret)
1323 goto error;
1324 }
1325
1326 return 0;
1327error:
1328 bio_list_put(bio_list);
1329 return -EIO;
1330}
1331
1332static void set_rbio_range_error(struct btrfs_raid_bio *rbio, struct bio *bio)
1333{
1334 struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
1335 u32 offset = (bio->bi_iter.bi_sector << SECTOR_SHIFT) -
1336 rbio->bioc->full_stripe_logical;
1337 int total_nr_sector = offset >> fs_info->sectorsize_bits;
1338
1339 ASSERT(total_nr_sector < rbio->nr_data * rbio->stripe_nsectors);
1340
1341 bitmap_set(rbio->error_bitmap, total_nr_sector,
1342 bio->bi_iter.bi_size >> fs_info->sectorsize_bits);
1343
1344 /*
1345 * Special handling for raid56_alloc_missing_rbio() used by
1346 * scrub/replace. Unlike call path in raid56_parity_recover(), they
1347 * pass an empty bio here. Thus we have to find out the missing device
1348 * and mark the stripe error instead.
1349 */
1350 if (bio->bi_iter.bi_size == 0) {
1351 bool found_missing = false;
1352 int stripe_nr;
1353
1354 for (stripe_nr = 0; stripe_nr < rbio->real_stripes; stripe_nr++) {
1355 if (!rbio->bioc->stripes[stripe_nr].dev->bdev) {
1356 found_missing = true;
1357 bitmap_set(rbio->error_bitmap,
1358 stripe_nr * rbio->stripe_nsectors,
1359 rbio->stripe_nsectors);
1360 }
1361 }
1362 ASSERT(found_missing);
1363 }
1364}
1365
1366/*
1367 * For subpage case, we can no longer set page Up-to-date directly for
1368 * stripe_pages[], thus we need to locate the sector.
1369 */
1370static struct sector_ptr *find_stripe_sector(struct btrfs_raid_bio *rbio,
1371 struct page *page,
1372 unsigned int pgoff)
1373{
1374 int i;
1375
1376 for (i = 0; i < rbio->nr_sectors; i++) {
1377 struct sector_ptr *sector = &rbio->stripe_sectors[i];
1378
1379 if (sector->page == page && sector->pgoff == pgoff)
1380 return sector;
1381 }
1382 return NULL;
1383}
1384
1385/*
1386 * this sets each page in the bio uptodate. It should only be used on private
1387 * rbio pages, nothing that comes in from the higher layers
1388 */
1389static void set_bio_pages_uptodate(struct btrfs_raid_bio *rbio, struct bio *bio)
1390{
1391 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
1392 struct bio_vec *bvec;
1393 struct bvec_iter_all iter_all;
1394
1395 ASSERT(!bio_flagged(bio, BIO_CLONED));
1396
1397 bio_for_each_segment_all(bvec, bio, iter_all) {
1398 struct sector_ptr *sector;
1399 int pgoff;
1400
1401 for (pgoff = bvec->bv_offset; pgoff - bvec->bv_offset < bvec->bv_len;
1402 pgoff += sectorsize) {
1403 sector = find_stripe_sector(rbio, bvec->bv_page, pgoff);
1404 ASSERT(sector);
1405 if (sector)
1406 sector->uptodate = 1;
1407 }
1408 }
1409}
1410
1411static int get_bio_sector_nr(struct btrfs_raid_bio *rbio, struct bio *bio)
1412{
1413 struct bio_vec *bv = bio_first_bvec_all(bio);
1414 int i;
1415
1416 for (i = 0; i < rbio->nr_sectors; i++) {
1417 struct sector_ptr *sector;
1418
1419 sector = &rbio->stripe_sectors[i];
1420 if (sector->page == bv->bv_page && sector->pgoff == bv->bv_offset)
1421 break;
1422 sector = &rbio->bio_sectors[i];
1423 if (sector->page == bv->bv_page && sector->pgoff == bv->bv_offset)
1424 break;
1425 }
1426 ASSERT(i < rbio->nr_sectors);
1427 return i;
1428}
1429
1430static void rbio_update_error_bitmap(struct btrfs_raid_bio *rbio, struct bio *bio)
1431{
1432 int total_sector_nr = get_bio_sector_nr(rbio, bio);
1433 u32 bio_size = 0;
1434 struct bio_vec *bvec;
1435 int i;
1436
1437 bio_for_each_bvec_all(bvec, bio, i)
1438 bio_size += bvec->bv_len;
1439
1440 /*
1441 * Since we can have multiple bios touching the error_bitmap, we cannot
1442 * call bitmap_set() without protection.
1443 *
1444 * Instead use set_bit() for each bit, as set_bit() itself is atomic.
1445 */
1446 for (i = total_sector_nr; i < total_sector_nr +
1447 (bio_size >> rbio->bioc->fs_info->sectorsize_bits); i++)
1448 set_bit(i, rbio->error_bitmap);
1449}
1450
1451/* Verify the data sectors at read time. */
1452static void verify_bio_data_sectors(struct btrfs_raid_bio *rbio,
1453 struct bio *bio)
1454{
1455 struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
1456 int total_sector_nr = get_bio_sector_nr(rbio, bio);
1457 struct bio_vec *bvec;
1458 struct bvec_iter_all iter_all;
1459
1460 /* No data csum for the whole stripe, no need to verify. */
1461 if (!rbio->csum_bitmap || !rbio->csum_buf)
1462 return;
1463
1464 /* P/Q stripes, they have no data csum to verify against. */
1465 if (total_sector_nr >= rbio->nr_data * rbio->stripe_nsectors)
1466 return;
1467
1468 bio_for_each_segment_all(bvec, bio, iter_all) {
1469 int bv_offset;
1470
1471 for (bv_offset = bvec->bv_offset;
1472 bv_offset < bvec->bv_offset + bvec->bv_len;
1473 bv_offset += fs_info->sectorsize, total_sector_nr++) {
1474 u8 csum_buf[BTRFS_CSUM_SIZE];
1475 u8 *expected_csum = rbio->csum_buf +
1476 total_sector_nr * fs_info->csum_size;
1477 int ret;
1478
1479 /* No csum for this sector, skip to the next sector. */
1480 if (!test_bit(total_sector_nr, rbio->csum_bitmap))
1481 continue;
1482
1483 ret = btrfs_check_sector_csum(fs_info, bvec->bv_page,
1484 bv_offset, csum_buf, expected_csum);
1485 if (ret < 0)
1486 set_bit(total_sector_nr, rbio->error_bitmap);
1487 }
1488 }
1489}
1490
1491static void raid_wait_read_end_io(struct bio *bio)
1492{
1493 struct btrfs_raid_bio *rbio = bio->bi_private;
1494
1495 if (bio->bi_status) {
1496 rbio_update_error_bitmap(rbio, bio);
1497 } else {
1498 set_bio_pages_uptodate(rbio, bio);
1499 verify_bio_data_sectors(rbio, bio);
1500 }
1501
1502 bio_put(bio);
1503 if (atomic_dec_and_test(&rbio->stripes_pending))
1504 wake_up(&rbio->io_wait);
1505}
1506
1507static void submit_read_wait_bio_list(struct btrfs_raid_bio *rbio,
1508 struct bio_list *bio_list)
1509{
1510 struct bio *bio;
1511
1512 atomic_set(&rbio->stripes_pending, bio_list_size(bio_list));
1513 while ((bio = bio_list_pop(bio_list))) {
1514 bio->bi_end_io = raid_wait_read_end_io;
1515
1516 if (trace_raid56_read_enabled()) {
1517 struct raid56_bio_trace_info trace_info = { 0 };
1518
1519 bio_get_trace_info(rbio, bio, &trace_info);
1520 trace_raid56_read(rbio, bio, &trace_info);
1521 }
1522 submit_bio(bio);
1523 }
1524
1525 wait_event(rbio->io_wait, atomic_read(&rbio->stripes_pending) == 0);
1526}
1527
1528static int alloc_rbio_data_pages(struct btrfs_raid_bio *rbio)
1529{
1530 const int data_pages = rbio->nr_data * rbio->stripe_npages;
1531 int ret;
1532
1533 ret = btrfs_alloc_page_array(data_pages, rbio->stripe_pages, 0);
1534 if (ret < 0)
1535 return ret;
1536
1537 index_stripe_sectors(rbio);
1538 return 0;
1539}
1540
1541/*
1542 * We use plugging call backs to collect full stripes.
1543 * Any time we get a partial stripe write while plugged
1544 * we collect it into a list. When the unplug comes down,
1545 * we sort the list by logical block number and merge
1546 * everything we can into the same rbios
1547 */
1548struct btrfs_plug_cb {
1549 struct blk_plug_cb cb;
1550 struct btrfs_fs_info *info;
1551 struct list_head rbio_list;
1552};
1553
1554/*
1555 * rbios on the plug list are sorted for easier merging.
1556 */
1557static int plug_cmp(void *priv, const struct list_head *a,
1558 const struct list_head *b)
1559{
1560 const struct btrfs_raid_bio *ra = container_of(a, struct btrfs_raid_bio,
1561 plug_list);
1562 const struct btrfs_raid_bio *rb = container_of(b, struct btrfs_raid_bio,
1563 plug_list);
1564 u64 a_sector = ra->bio_list.head->bi_iter.bi_sector;
1565 u64 b_sector = rb->bio_list.head->bi_iter.bi_sector;
1566
1567 if (a_sector < b_sector)
1568 return -1;
1569 if (a_sector > b_sector)
1570 return 1;
1571 return 0;
1572}
1573
1574static void raid_unplug(struct blk_plug_cb *cb, bool from_schedule)
1575{
1576 struct btrfs_plug_cb *plug = container_of(cb, struct btrfs_plug_cb, cb);
1577 struct btrfs_raid_bio *cur;
1578 struct btrfs_raid_bio *last = NULL;
1579
1580 list_sort(NULL, &plug->rbio_list, plug_cmp);
1581
1582 while (!list_empty(&plug->rbio_list)) {
1583 cur = list_entry(plug->rbio_list.next,
1584 struct btrfs_raid_bio, plug_list);
1585 list_del_init(&cur->plug_list);
1586
1587 if (rbio_is_full(cur)) {
1588 /* We have a full stripe, queue it down. */
1589 start_async_work(cur, rmw_rbio_work);
1590 continue;
1591 }
1592 if (last) {
1593 if (rbio_can_merge(last, cur)) {
1594 merge_rbio(last, cur);
1595 free_raid_bio(cur);
1596 continue;
1597 }
1598 start_async_work(last, rmw_rbio_work);
1599 }
1600 last = cur;
1601 }
1602 if (last)
1603 start_async_work(last, rmw_rbio_work);
1604 kfree(plug);
1605}
1606
1607/* Add the original bio into rbio->bio_list, and update rbio::dbitmap. */
1608static void rbio_add_bio(struct btrfs_raid_bio *rbio, struct bio *orig_bio)
1609{
1610 const struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
1611 const u64 orig_logical = orig_bio->bi_iter.bi_sector << SECTOR_SHIFT;
1612 const u64 full_stripe_start = rbio->bioc->full_stripe_logical;
1613 const u32 orig_len = orig_bio->bi_iter.bi_size;
1614 const u32 sectorsize = fs_info->sectorsize;
1615 u64 cur_logical;
1616
1617 ASSERT(orig_logical >= full_stripe_start &&
1618 orig_logical + orig_len <= full_stripe_start +
1619 rbio->nr_data * BTRFS_STRIPE_LEN);
1620
1621 bio_list_add(&rbio->bio_list, orig_bio);
1622 rbio->bio_list_bytes += orig_bio->bi_iter.bi_size;
1623
1624 /* Update the dbitmap. */
1625 for (cur_logical = orig_logical; cur_logical < orig_logical + orig_len;
1626 cur_logical += sectorsize) {
1627 int bit = ((u32)(cur_logical - full_stripe_start) >>
1628 fs_info->sectorsize_bits) % rbio->stripe_nsectors;
1629
1630 set_bit(bit, &rbio->dbitmap);
1631 }
1632}
1633
1634/*
1635 * our main entry point for writes from the rest of the FS.
1636 */
1637void raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc)
1638{
1639 struct btrfs_fs_info *fs_info = bioc->fs_info;
1640 struct btrfs_raid_bio *rbio;
1641 struct btrfs_plug_cb *plug = NULL;
1642 struct blk_plug_cb *cb;
1643
1644 rbio = alloc_rbio(fs_info, bioc);
1645 if (IS_ERR(rbio)) {
1646 bio->bi_status = errno_to_blk_status(PTR_ERR(rbio));
1647 bio_endio(bio);
1648 return;
1649 }
1650 rbio->operation = BTRFS_RBIO_WRITE;
1651 rbio_add_bio(rbio, bio);
1652
1653 /*
1654 * Don't plug on full rbios, just get them out the door
1655 * as quickly as we can
1656 */
1657 if (!rbio_is_full(rbio)) {
1658 cb = blk_check_plugged(raid_unplug, fs_info, sizeof(*plug));
1659 if (cb) {
1660 plug = container_of(cb, struct btrfs_plug_cb, cb);
1661 if (!plug->info) {
1662 plug->info = fs_info;
1663 INIT_LIST_HEAD(&plug->rbio_list);
1664 }
1665 list_add_tail(&rbio->plug_list, &plug->rbio_list);
1666 return;
1667 }
1668 }
1669
1670 /*
1671 * Either we don't have any existing plug, or we're doing a full stripe,
1672 * queue the rmw work now.
1673 */
1674 start_async_work(rbio, rmw_rbio_work);
1675}
1676
1677static int verify_one_sector(struct btrfs_raid_bio *rbio,
1678 int stripe_nr, int sector_nr)
1679{
1680 struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
1681 struct sector_ptr *sector;
1682 u8 csum_buf[BTRFS_CSUM_SIZE];
1683 u8 *csum_expected;
1684 int ret;
1685
1686 if (!rbio->csum_bitmap || !rbio->csum_buf)
1687 return 0;
1688
1689 /* No way to verify P/Q as they are not covered by data csum. */
1690 if (stripe_nr >= rbio->nr_data)
1691 return 0;
1692 /*
1693 * If we're rebuilding a read, we have to use pages from the
1694 * bio list if possible.
1695 */
1696 if (rbio->operation == BTRFS_RBIO_READ_REBUILD) {
1697 sector = sector_in_rbio(rbio, stripe_nr, sector_nr, 0);
1698 } else {
1699 sector = rbio_stripe_sector(rbio, stripe_nr, sector_nr);
1700 }
1701
1702 ASSERT(sector->page);
1703
1704 csum_expected = rbio->csum_buf +
1705 (stripe_nr * rbio->stripe_nsectors + sector_nr) *
1706 fs_info->csum_size;
1707 ret = btrfs_check_sector_csum(fs_info, sector->page, sector->pgoff,
1708 csum_buf, csum_expected);
1709 return ret;
1710}
1711
1712/*
1713 * Recover a vertical stripe specified by @sector_nr.
1714 * @*pointers are the pre-allocated pointers by the caller, so we don't
1715 * need to allocate/free the pointers again and again.
1716 */
1717static int recover_vertical(struct btrfs_raid_bio *rbio, int sector_nr,
1718 void **pointers, void **unmap_array)
1719{
1720 struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
1721 struct sector_ptr *sector;
1722 const u32 sectorsize = fs_info->sectorsize;
1723 int found_errors;
1724 int faila;
1725 int failb;
1726 int stripe_nr;
1727 int ret = 0;
1728
1729 /*
1730 * Now we just use bitmap to mark the horizontal stripes in
1731 * which we have data when doing parity scrub.
1732 */
1733 if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB &&
1734 !test_bit(sector_nr, &rbio->dbitmap))
1735 return 0;
1736
1737 found_errors = get_rbio_veritical_errors(rbio, sector_nr, &faila,
1738 &failb);
1739 /*
1740 * No errors in the vertical stripe, skip it. Can happen for recovery
1741 * which only part of a stripe failed csum check.
1742 */
1743 if (!found_errors)
1744 return 0;
1745
1746 if (found_errors > rbio->bioc->max_errors)
1747 return -EIO;
1748
1749 /*
1750 * Setup our array of pointers with sectors from each stripe
1751 *
1752 * NOTE: store a duplicate array of pointers to preserve the
1753 * pointer order.
1754 */
1755 for (stripe_nr = 0; stripe_nr < rbio->real_stripes; stripe_nr++) {
1756 /*
1757 * If we're rebuilding a read, we have to use pages from the
1758 * bio list if possible.
1759 */
1760 if (rbio->operation == BTRFS_RBIO_READ_REBUILD) {
1761 sector = sector_in_rbio(rbio, stripe_nr, sector_nr, 0);
1762 } else {
1763 sector = rbio_stripe_sector(rbio, stripe_nr, sector_nr);
1764 }
1765 ASSERT(sector->page);
1766 pointers[stripe_nr] = kmap_local_page(sector->page) +
1767 sector->pgoff;
1768 unmap_array[stripe_nr] = pointers[stripe_nr];
1769 }
1770
1771 /* All raid6 handling here */
1772 if (rbio->bioc->map_type & BTRFS_BLOCK_GROUP_RAID6) {
1773 /* Single failure, rebuild from parity raid5 style */
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 * We have nothing to do, just skip the
1780 * recovery for this stripe.
1781 */
1782 goto cleanup;
1783 /*
1784 * a single failure in raid6 is rebuilt
1785 * in the pstripe code below
1786 */
1787 goto pstripe;
1788 }
1789
1790 /*
1791 * If the q stripe is failed, do a pstripe reconstruction from
1792 * the xors.
1793 * If both the q stripe and the P stripe are failed, we're
1794 * here due to a crc mismatch and we can't give them the
1795 * data they want.
1796 */
1797 if (failb == rbio->real_stripes - 1) {
1798 if (faila == rbio->real_stripes - 2)
1799 /*
1800 * Only P and Q are corrupted.
1801 * We only care about data stripes recovery,
1802 * can skip this vertical stripe.
1803 */
1804 goto cleanup;
1805 /*
1806 * Otherwise we have one bad data stripe and
1807 * a good P stripe. raid5!
1808 */
1809 goto pstripe;
1810 }
1811
1812 if (failb == rbio->real_stripes - 2) {
1813 raid6_datap_recov(rbio->real_stripes, sectorsize,
1814 faila, pointers);
1815 } else {
1816 raid6_2data_recov(rbio->real_stripes, sectorsize,
1817 faila, failb, pointers);
1818 }
1819 } else {
1820 void *p;
1821
1822 /* Rebuild from P stripe here (raid5 or raid6). */
1823 ASSERT(failb == -1);
1824pstripe:
1825 /* Copy parity block into failed block to start with */
1826 memcpy(pointers[faila], pointers[rbio->nr_data], sectorsize);
1827
1828 /* Rearrange the pointer array */
1829 p = pointers[faila];
1830 for (stripe_nr = faila; stripe_nr < rbio->nr_data - 1;
1831 stripe_nr++)
1832 pointers[stripe_nr] = pointers[stripe_nr + 1];
1833 pointers[rbio->nr_data - 1] = p;
1834
1835 /* Xor in the rest */
1836 run_xor(pointers, rbio->nr_data - 1, sectorsize);
1837
1838 }
1839
1840 /*
1841 * No matter if this is a RMW or recovery, we should have all
1842 * failed sectors repaired in the vertical stripe, thus they are now
1843 * uptodate.
1844 * Especially if we determine to cache the rbio, we need to
1845 * have at least all data sectors uptodate.
1846 *
1847 * If possible, also check if the repaired sector matches its data
1848 * checksum.
1849 */
1850 if (faila >= 0) {
1851 ret = verify_one_sector(rbio, faila, sector_nr);
1852 if (ret < 0)
1853 goto cleanup;
1854
1855 sector = rbio_stripe_sector(rbio, faila, sector_nr);
1856 sector->uptodate = 1;
1857 }
1858 if (failb >= 0) {
1859 ret = verify_one_sector(rbio, failb, sector_nr);
1860 if (ret < 0)
1861 goto cleanup;
1862
1863 sector = rbio_stripe_sector(rbio, failb, sector_nr);
1864 sector->uptodate = 1;
1865 }
1866
1867cleanup:
1868 for (stripe_nr = rbio->real_stripes - 1; stripe_nr >= 0; stripe_nr--)
1869 kunmap_local(unmap_array[stripe_nr]);
1870 return ret;
1871}
1872
1873static int recover_sectors(struct btrfs_raid_bio *rbio)
1874{
1875 void **pointers = NULL;
1876 void **unmap_array = NULL;
1877 int sectornr;
1878 int ret = 0;
1879
1880 /*
1881 * @pointers array stores the pointer for each sector.
1882 *
1883 * @unmap_array stores copy of pointers that does not get reordered
1884 * during reconstruction so that kunmap_local works.
1885 */
1886 pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
1887 unmap_array = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
1888 if (!pointers || !unmap_array) {
1889 ret = -ENOMEM;
1890 goto out;
1891 }
1892
1893 if (rbio->operation == BTRFS_RBIO_READ_REBUILD) {
1894 spin_lock(&rbio->bio_list_lock);
1895 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1896 spin_unlock(&rbio->bio_list_lock);
1897 }
1898
1899 index_rbio_pages(rbio);
1900
1901 for (sectornr = 0; sectornr < rbio->stripe_nsectors; sectornr++) {
1902 ret = recover_vertical(rbio, sectornr, pointers, unmap_array);
1903 if (ret < 0)
1904 break;
1905 }
1906
1907out:
1908 kfree(pointers);
1909 kfree(unmap_array);
1910 return ret;
1911}
1912
1913static void recover_rbio(struct btrfs_raid_bio *rbio)
1914{
1915 struct bio_list bio_list = BIO_EMPTY_LIST;
1916 int total_sector_nr;
1917 int ret = 0;
1918
1919 /*
1920 * Either we're doing recover for a read failure or degraded write,
1921 * caller should have set error bitmap correctly.
1922 */
1923 ASSERT(bitmap_weight(rbio->error_bitmap, rbio->nr_sectors));
1924
1925 /* For recovery, we need to read all sectors including P/Q. */
1926 ret = alloc_rbio_pages(rbio);
1927 if (ret < 0)
1928 goto out;
1929
1930 index_rbio_pages(rbio);
1931
1932 /*
1933 * Read everything that hasn't failed. However this time we will
1934 * not trust any cached sector.
1935 * As we may read out some stale data but higher layer is not reading
1936 * that stale part.
1937 *
1938 * So here we always re-read everything in recovery path.
1939 */
1940 for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
1941 total_sector_nr++) {
1942 int stripe = total_sector_nr / rbio->stripe_nsectors;
1943 int sectornr = total_sector_nr % rbio->stripe_nsectors;
1944 struct sector_ptr *sector;
1945
1946 /*
1947 * Skip the range which has error. It can be a range which is
1948 * marked error (for csum mismatch), or it can be a missing
1949 * device.
1950 */
1951 if (!rbio->bioc->stripes[stripe].dev->bdev ||
1952 test_bit(total_sector_nr, rbio->error_bitmap)) {
1953 /*
1954 * Also set the error bit for missing device, which
1955 * may not yet have its error bit set.
1956 */
1957 set_bit(total_sector_nr, rbio->error_bitmap);
1958 continue;
1959 }
1960
1961 sector = rbio_stripe_sector(rbio, stripe, sectornr);
1962 ret = rbio_add_io_sector(rbio, &bio_list, sector, stripe,
1963 sectornr, REQ_OP_READ);
1964 if (ret < 0) {
1965 bio_list_put(&bio_list);
1966 goto out;
1967 }
1968 }
1969
1970 submit_read_wait_bio_list(rbio, &bio_list);
1971 ret = recover_sectors(rbio);
1972out:
1973 rbio_orig_end_io(rbio, errno_to_blk_status(ret));
1974}
1975
1976static void recover_rbio_work(struct work_struct *work)
1977{
1978 struct btrfs_raid_bio *rbio;
1979
1980 rbio = container_of(work, struct btrfs_raid_bio, work);
1981 if (!lock_stripe_add(rbio))
1982 recover_rbio(rbio);
1983}
1984
1985static void recover_rbio_work_locked(struct work_struct *work)
1986{
1987 recover_rbio(container_of(work, struct btrfs_raid_bio, work));
1988}
1989
1990static void set_rbio_raid6_extra_error(struct btrfs_raid_bio *rbio, int mirror_num)
1991{
1992 bool found = false;
1993 int sector_nr;
1994
1995 /*
1996 * This is for RAID6 extra recovery tries, thus mirror number should
1997 * be large than 2.
1998 * Mirror 1 means read from data stripes. Mirror 2 means rebuild using
1999 * RAID5 methods.
2000 */
2001 ASSERT(mirror_num > 2);
2002 for (sector_nr = 0; sector_nr < rbio->stripe_nsectors; sector_nr++) {
2003 int found_errors;
2004 int faila;
2005 int failb;
2006
2007 found_errors = get_rbio_veritical_errors(rbio, sector_nr,
2008 &faila, &failb);
2009 /* This vertical stripe doesn't have errors. */
2010 if (!found_errors)
2011 continue;
2012
2013 /*
2014 * If we found errors, there should be only one error marked
2015 * by previous set_rbio_range_error().
2016 */
2017 ASSERT(found_errors == 1);
2018 found = true;
2019
2020 /* Now select another stripe to mark as error. */
2021 failb = rbio->real_stripes - (mirror_num - 1);
2022 if (failb <= faila)
2023 failb--;
2024
2025 /* Set the extra bit in error bitmap. */
2026 if (failb >= 0)
2027 set_bit(failb * rbio->stripe_nsectors + sector_nr,
2028 rbio->error_bitmap);
2029 }
2030
2031 /* We should found at least one vertical stripe with error.*/
2032 ASSERT(found);
2033}
2034
2035/*
2036 * the main entry point for reads from the higher layers. This
2037 * is really only called when the normal read path had a failure,
2038 * so we assume the bio they send down corresponds to a failed part
2039 * of the drive.
2040 */
2041void raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
2042 int mirror_num)
2043{
2044 struct btrfs_fs_info *fs_info = bioc->fs_info;
2045 struct btrfs_raid_bio *rbio;
2046
2047 rbio = alloc_rbio(fs_info, bioc);
2048 if (IS_ERR(rbio)) {
2049 bio->bi_status = errno_to_blk_status(PTR_ERR(rbio));
2050 bio_endio(bio);
2051 return;
2052 }
2053
2054 rbio->operation = BTRFS_RBIO_READ_REBUILD;
2055 rbio_add_bio(rbio, bio);
2056
2057 set_rbio_range_error(rbio, bio);
2058
2059 /*
2060 * Loop retry:
2061 * for 'mirror == 2', reconstruct from all other stripes.
2062 * for 'mirror_num > 2', select a stripe to fail on every retry.
2063 */
2064 if (mirror_num > 2)
2065 set_rbio_raid6_extra_error(rbio, mirror_num);
2066
2067 start_async_work(rbio, recover_rbio_work);
2068}
2069
2070static void fill_data_csums(struct btrfs_raid_bio *rbio)
2071{
2072 struct btrfs_fs_info *fs_info = rbio->bioc->fs_info;
2073 struct btrfs_root *csum_root = btrfs_csum_root(fs_info,
2074 rbio->bioc->full_stripe_logical);
2075 const u64 start = rbio->bioc->full_stripe_logical;
2076 const u32 len = (rbio->nr_data * rbio->stripe_nsectors) <<
2077 fs_info->sectorsize_bits;
2078 int ret;
2079
2080 /* The rbio should not have its csum buffer initialized. */
2081 ASSERT(!rbio->csum_buf && !rbio->csum_bitmap);
2082
2083 /*
2084 * Skip the csum search if:
2085 *
2086 * - The rbio doesn't belong to data block groups
2087 * Then we are doing IO for tree blocks, no need to search csums.
2088 *
2089 * - The rbio belongs to mixed block groups
2090 * This is to avoid deadlock, as we're already holding the full
2091 * stripe lock, if we trigger a metadata read, and it needs to do
2092 * raid56 recovery, we will deadlock.
2093 */
2094 if (!(rbio->bioc->map_type & BTRFS_BLOCK_GROUP_DATA) ||
2095 rbio->bioc->map_type & BTRFS_BLOCK_GROUP_METADATA)
2096 return;
2097
2098 rbio->csum_buf = kzalloc(rbio->nr_data * rbio->stripe_nsectors *
2099 fs_info->csum_size, GFP_NOFS);
2100 rbio->csum_bitmap = bitmap_zalloc(rbio->nr_data * rbio->stripe_nsectors,
2101 GFP_NOFS);
2102 if (!rbio->csum_buf || !rbio->csum_bitmap) {
2103 ret = -ENOMEM;
2104 goto error;
2105 }
2106
2107 ret = btrfs_lookup_csums_bitmap(csum_root, NULL, start, start + len - 1,
2108 rbio->csum_buf, rbio->csum_bitmap);
2109 if (ret < 0)
2110 goto error;
2111 if (bitmap_empty(rbio->csum_bitmap, len >> fs_info->sectorsize_bits))
2112 goto no_csum;
2113 return;
2114
2115error:
2116 /*
2117 * We failed to allocate memory or grab the csum, but it's not fatal,
2118 * we can still continue. But better to warn users that RMW is no
2119 * longer safe for this particular sub-stripe write.
2120 */
2121 btrfs_warn_rl(fs_info,
2122"sub-stripe write for full stripe %llu is not safe, failed to get csum: %d",
2123 rbio->bioc->full_stripe_logical, ret);
2124no_csum:
2125 kfree(rbio->csum_buf);
2126 bitmap_free(rbio->csum_bitmap);
2127 rbio->csum_buf = NULL;
2128 rbio->csum_bitmap = NULL;
2129}
2130
2131static int rmw_read_wait_recover(struct btrfs_raid_bio *rbio)
2132{
2133 struct bio_list bio_list = BIO_EMPTY_LIST;
2134 int total_sector_nr;
2135 int ret = 0;
2136
2137 /*
2138 * Fill the data csums we need for data verification. We need to fill
2139 * the csum_bitmap/csum_buf first, as our endio function will try to
2140 * verify the data sectors.
2141 */
2142 fill_data_csums(rbio);
2143
2144 /*
2145 * Build a list of bios to read all sectors (including data and P/Q).
2146 *
2147 * This behavior is to compensate the later csum verification and recovery.
2148 */
2149 for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
2150 total_sector_nr++) {
2151 struct sector_ptr *sector;
2152 int stripe = total_sector_nr / rbio->stripe_nsectors;
2153 int sectornr = total_sector_nr % rbio->stripe_nsectors;
2154
2155 sector = rbio_stripe_sector(rbio, stripe, sectornr);
2156 ret = rbio_add_io_sector(rbio, &bio_list, sector,
2157 stripe, sectornr, REQ_OP_READ);
2158 if (ret) {
2159 bio_list_put(&bio_list);
2160 return ret;
2161 }
2162 }
2163
2164 /*
2165 * We may or may not have any corrupted sectors (including missing dev
2166 * and csum mismatch), just let recover_sectors() to handle them all.
2167 */
2168 submit_read_wait_bio_list(rbio, &bio_list);
2169 return recover_sectors(rbio);
2170}
2171
2172static void raid_wait_write_end_io(struct bio *bio)
2173{
2174 struct btrfs_raid_bio *rbio = bio->bi_private;
2175 blk_status_t err = bio->bi_status;
2176
2177 if (err)
2178 rbio_update_error_bitmap(rbio, bio);
2179 bio_put(bio);
2180 if (atomic_dec_and_test(&rbio->stripes_pending))
2181 wake_up(&rbio->io_wait);
2182}
2183
2184static void submit_write_bios(struct btrfs_raid_bio *rbio,
2185 struct bio_list *bio_list)
2186{
2187 struct bio *bio;
2188
2189 atomic_set(&rbio->stripes_pending, bio_list_size(bio_list));
2190 while ((bio = bio_list_pop(bio_list))) {
2191 bio->bi_end_io = raid_wait_write_end_io;
2192
2193 if (trace_raid56_write_enabled()) {
2194 struct raid56_bio_trace_info trace_info = { 0 };
2195
2196 bio_get_trace_info(rbio, bio, &trace_info);
2197 trace_raid56_write(rbio, bio, &trace_info);
2198 }
2199 submit_bio(bio);
2200 }
2201}
2202
2203/*
2204 * To determine if we need to read any sector from the disk.
2205 * Should only be utilized in RMW path, to skip cached rbio.
2206 */
2207static bool need_read_stripe_sectors(struct btrfs_raid_bio *rbio)
2208{
2209 int i;
2210
2211 for (i = 0; i < rbio->nr_data * rbio->stripe_nsectors; i++) {
2212 struct sector_ptr *sector = &rbio->stripe_sectors[i];
2213
2214 /*
2215 * We have a sector which doesn't have page nor uptodate,
2216 * thus this rbio can not be cached one, as cached one must
2217 * have all its data sectors present and uptodate.
2218 */
2219 if (!sector->page || !sector->uptodate)
2220 return true;
2221 }
2222 return false;
2223}
2224
2225static void rmw_rbio(struct btrfs_raid_bio *rbio)
2226{
2227 struct bio_list bio_list;
2228 int sectornr;
2229 int ret = 0;
2230
2231 /*
2232 * Allocate the pages for parity first, as P/Q pages will always be
2233 * needed for both full-stripe and sub-stripe writes.
2234 */
2235 ret = alloc_rbio_parity_pages(rbio);
2236 if (ret < 0)
2237 goto out;
2238
2239 /*
2240 * Either full stripe write, or we have every data sector already
2241 * cached, can go to write path immediately.
2242 */
2243 if (!rbio_is_full(rbio) && need_read_stripe_sectors(rbio)) {
2244 /*
2245 * Now we're doing sub-stripe write, also need all data stripes
2246 * to do the full RMW.
2247 */
2248 ret = alloc_rbio_data_pages(rbio);
2249 if (ret < 0)
2250 goto out;
2251
2252 index_rbio_pages(rbio);
2253
2254 ret = rmw_read_wait_recover(rbio);
2255 if (ret < 0)
2256 goto out;
2257 }
2258
2259 /*
2260 * At this stage we're not allowed to add any new bios to the
2261 * bio list any more, anyone else that wants to change this stripe
2262 * needs to do their own rmw.
2263 */
2264 spin_lock(&rbio->bio_list_lock);
2265 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
2266 spin_unlock(&rbio->bio_list_lock);
2267
2268 bitmap_clear(rbio->error_bitmap, 0, rbio->nr_sectors);
2269
2270 index_rbio_pages(rbio);
2271
2272 /*
2273 * We don't cache full rbios because we're assuming
2274 * the higher layers are unlikely to use this area of
2275 * the disk again soon. If they do use it again,
2276 * hopefully they will send another full bio.
2277 */
2278 if (!rbio_is_full(rbio))
2279 cache_rbio_pages(rbio);
2280 else
2281 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
2282
2283 for (sectornr = 0; sectornr < rbio->stripe_nsectors; sectornr++)
2284 generate_pq_vertical(rbio, sectornr);
2285
2286 bio_list_init(&bio_list);
2287 ret = rmw_assemble_write_bios(rbio, &bio_list);
2288 if (ret < 0)
2289 goto out;
2290
2291 /* We should have at least one bio assembled. */
2292 ASSERT(bio_list_size(&bio_list));
2293 submit_write_bios(rbio, &bio_list);
2294 wait_event(rbio->io_wait, atomic_read(&rbio->stripes_pending) == 0);
2295
2296 /* We may have more errors than our tolerance during the read. */
2297 for (sectornr = 0; sectornr < rbio->stripe_nsectors; sectornr++) {
2298 int found_errors;
2299
2300 found_errors = get_rbio_veritical_errors(rbio, sectornr, NULL, NULL);
2301 if (found_errors > rbio->bioc->max_errors) {
2302 ret = -EIO;
2303 break;
2304 }
2305 }
2306out:
2307 rbio_orig_end_io(rbio, errno_to_blk_status(ret));
2308}
2309
2310static void rmw_rbio_work(struct work_struct *work)
2311{
2312 struct btrfs_raid_bio *rbio;
2313
2314 rbio = container_of(work, struct btrfs_raid_bio, work);
2315 if (lock_stripe_add(rbio) == 0)
2316 rmw_rbio(rbio);
2317}
2318
2319static void rmw_rbio_work_locked(struct work_struct *work)
2320{
2321 rmw_rbio(container_of(work, struct btrfs_raid_bio, work));
2322}
2323
2324/*
2325 * The following code is used to scrub/replace the parity stripe
2326 *
2327 * Caller must have already increased bio_counter for getting @bioc.
2328 *
2329 * Note: We need make sure all the pages that add into the scrub/replace
2330 * raid bio are correct and not be changed during the scrub/replace. That
2331 * is those pages just hold metadata or file data with checksum.
2332 */
2333
2334struct btrfs_raid_bio *raid56_parity_alloc_scrub_rbio(struct bio *bio,
2335 struct btrfs_io_context *bioc,
2336 struct btrfs_device *scrub_dev,
2337 unsigned long *dbitmap, int stripe_nsectors)
2338{
2339 struct btrfs_fs_info *fs_info = bioc->fs_info;
2340 struct btrfs_raid_bio *rbio;
2341 int i;
2342
2343 rbio = alloc_rbio(fs_info, bioc);
2344 if (IS_ERR(rbio))
2345 return NULL;
2346 bio_list_add(&rbio->bio_list, bio);
2347 /*
2348 * This is a special bio which is used to hold the completion handler
2349 * and make the scrub rbio is similar to the other types
2350 */
2351 ASSERT(!bio->bi_iter.bi_size);
2352 rbio->operation = BTRFS_RBIO_PARITY_SCRUB;
2353
2354 /*
2355 * After mapping bioc with BTRFS_MAP_WRITE, parities have been sorted
2356 * to the end position, so this search can start from the first parity
2357 * stripe.
2358 */
2359 for (i = rbio->nr_data; i < rbio->real_stripes; i++) {
2360 if (bioc->stripes[i].dev == scrub_dev) {
2361 rbio->scrubp = i;
2362 break;
2363 }
2364 }
2365 ASSERT(i < rbio->real_stripes);
2366
2367 bitmap_copy(&rbio->dbitmap, dbitmap, stripe_nsectors);
2368 return rbio;
2369}
2370
2371/*
2372 * We just scrub the parity that we have correct data on the same horizontal,
2373 * so we needn't allocate all pages for all the stripes.
2374 */
2375static int alloc_rbio_essential_pages(struct btrfs_raid_bio *rbio)
2376{
2377 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
2378 int total_sector_nr;
2379
2380 for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
2381 total_sector_nr++) {
2382 struct page *page;
2383 int sectornr = total_sector_nr % rbio->stripe_nsectors;
2384 int index = (total_sector_nr * sectorsize) >> PAGE_SHIFT;
2385
2386 if (!test_bit(sectornr, &rbio->dbitmap))
2387 continue;
2388 if (rbio->stripe_pages[index])
2389 continue;
2390 page = alloc_page(GFP_NOFS);
2391 if (!page)
2392 return -ENOMEM;
2393 rbio->stripe_pages[index] = page;
2394 }
2395 index_stripe_sectors(rbio);
2396 return 0;
2397}
2398
2399static int finish_parity_scrub(struct btrfs_raid_bio *rbio)
2400{
2401 struct btrfs_io_context *bioc = rbio->bioc;
2402 const u32 sectorsize = bioc->fs_info->sectorsize;
2403 void **pointers = rbio->finish_pointers;
2404 unsigned long *pbitmap = &rbio->finish_pbitmap;
2405 int nr_data = rbio->nr_data;
2406 int stripe;
2407 int sectornr;
2408 bool has_qstripe;
2409 struct sector_ptr p_sector = { 0 };
2410 struct sector_ptr q_sector = { 0 };
2411 struct bio_list bio_list;
2412 int is_replace = 0;
2413 int ret;
2414
2415 bio_list_init(&bio_list);
2416
2417 if (rbio->real_stripes - rbio->nr_data == 1)
2418 has_qstripe = false;
2419 else if (rbio->real_stripes - rbio->nr_data == 2)
2420 has_qstripe = true;
2421 else
2422 BUG();
2423
2424 /*
2425 * Replace is running and our P/Q stripe is being replaced, then we
2426 * need to duplicate the final write to replace target.
2427 */
2428 if (bioc->replace_nr_stripes && bioc->replace_stripe_src == rbio->scrubp) {
2429 is_replace = 1;
2430 bitmap_copy(pbitmap, &rbio->dbitmap, rbio->stripe_nsectors);
2431 }
2432
2433 /*
2434 * Because the higher layers(scrubber) are unlikely to
2435 * use this area of the disk again soon, so don't cache
2436 * it.
2437 */
2438 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
2439
2440 p_sector.page = alloc_page(GFP_NOFS);
2441 if (!p_sector.page)
2442 return -ENOMEM;
2443 p_sector.pgoff = 0;
2444 p_sector.uptodate = 1;
2445
2446 if (has_qstripe) {
2447 /* RAID6, allocate and map temp space for the Q stripe */
2448 q_sector.page = alloc_page(GFP_NOFS);
2449 if (!q_sector.page) {
2450 __free_page(p_sector.page);
2451 p_sector.page = NULL;
2452 return -ENOMEM;
2453 }
2454 q_sector.pgoff = 0;
2455 q_sector.uptodate = 1;
2456 pointers[rbio->real_stripes - 1] = kmap_local_page(q_sector.page);
2457 }
2458
2459 bitmap_clear(rbio->error_bitmap, 0, rbio->nr_sectors);
2460
2461 /* Map the parity stripe just once */
2462 pointers[nr_data] = kmap_local_page(p_sector.page);
2463
2464 for_each_set_bit(sectornr, &rbio->dbitmap, rbio->stripe_nsectors) {
2465 struct sector_ptr *sector;
2466 void *parity;
2467
2468 /* first collect one page from each data stripe */
2469 for (stripe = 0; stripe < nr_data; stripe++) {
2470 sector = sector_in_rbio(rbio, stripe, sectornr, 0);
2471 pointers[stripe] = kmap_local_page(sector->page) +
2472 sector->pgoff;
2473 }
2474
2475 if (has_qstripe) {
2476 /* RAID6, call the library function to fill in our P/Q */
2477 raid6_call.gen_syndrome(rbio->real_stripes, sectorsize,
2478 pointers);
2479 } else {
2480 /* raid5 */
2481 memcpy(pointers[nr_data], pointers[0], sectorsize);
2482 run_xor(pointers + 1, nr_data - 1, sectorsize);
2483 }
2484
2485 /* Check scrubbing parity and repair it */
2486 sector = rbio_stripe_sector(rbio, rbio->scrubp, sectornr);
2487 parity = kmap_local_page(sector->page) + sector->pgoff;
2488 if (memcmp(parity, pointers[rbio->scrubp], sectorsize) != 0)
2489 memcpy(parity, pointers[rbio->scrubp], sectorsize);
2490 else
2491 /* Parity is right, needn't writeback */
2492 bitmap_clear(&rbio->dbitmap, sectornr, 1);
2493 kunmap_local(parity);
2494
2495 for (stripe = nr_data - 1; stripe >= 0; stripe--)
2496 kunmap_local(pointers[stripe]);
2497 }
2498
2499 kunmap_local(pointers[nr_data]);
2500 __free_page(p_sector.page);
2501 p_sector.page = NULL;
2502 if (q_sector.page) {
2503 kunmap_local(pointers[rbio->real_stripes - 1]);
2504 __free_page(q_sector.page);
2505 q_sector.page = NULL;
2506 }
2507
2508 /*
2509 * time to start writing. Make bios for everything from the
2510 * higher layers (the bio_list in our rbio) and our p/q. Ignore
2511 * everything else.
2512 */
2513 for_each_set_bit(sectornr, &rbio->dbitmap, rbio->stripe_nsectors) {
2514 struct sector_ptr *sector;
2515
2516 sector = rbio_stripe_sector(rbio, rbio->scrubp, sectornr);
2517 ret = rbio_add_io_sector(rbio, &bio_list, sector, rbio->scrubp,
2518 sectornr, REQ_OP_WRITE);
2519 if (ret)
2520 goto cleanup;
2521 }
2522
2523 if (!is_replace)
2524 goto submit_write;
2525
2526 /*
2527 * Replace is running and our parity stripe needs to be duplicated to
2528 * the target device. Check we have a valid source stripe number.
2529 */
2530 ASSERT(rbio->bioc->replace_stripe_src >= 0);
2531 for_each_set_bit(sectornr, pbitmap, rbio->stripe_nsectors) {
2532 struct sector_ptr *sector;
2533
2534 sector = rbio_stripe_sector(rbio, rbio->scrubp, sectornr);
2535 ret = rbio_add_io_sector(rbio, &bio_list, sector,
2536 rbio->real_stripes,
2537 sectornr, REQ_OP_WRITE);
2538 if (ret)
2539 goto cleanup;
2540 }
2541
2542submit_write:
2543 submit_write_bios(rbio, &bio_list);
2544 return 0;
2545
2546cleanup:
2547 bio_list_put(&bio_list);
2548 return ret;
2549}
2550
2551static inline int is_data_stripe(struct btrfs_raid_bio *rbio, int stripe)
2552{
2553 if (stripe >= 0 && stripe < rbio->nr_data)
2554 return 1;
2555 return 0;
2556}
2557
2558static int recover_scrub_rbio(struct btrfs_raid_bio *rbio)
2559{
2560 void **pointers = NULL;
2561 void **unmap_array = NULL;
2562 int sector_nr;
2563 int ret = 0;
2564
2565 /*
2566 * @pointers array stores the pointer for each sector.
2567 *
2568 * @unmap_array stores copy of pointers that does not get reordered
2569 * during reconstruction so that kunmap_local works.
2570 */
2571 pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
2572 unmap_array = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
2573 if (!pointers || !unmap_array) {
2574 ret = -ENOMEM;
2575 goto out;
2576 }
2577
2578 for (sector_nr = 0; sector_nr < rbio->stripe_nsectors; sector_nr++) {
2579 int dfail = 0, failp = -1;
2580 int faila;
2581 int failb;
2582 int found_errors;
2583
2584 found_errors = get_rbio_veritical_errors(rbio, sector_nr,
2585 &faila, &failb);
2586 if (found_errors > rbio->bioc->max_errors) {
2587 ret = -EIO;
2588 goto out;
2589 }
2590 if (found_errors == 0)
2591 continue;
2592
2593 /* We should have at least one error here. */
2594 ASSERT(faila >= 0 || failb >= 0);
2595
2596 if (is_data_stripe(rbio, faila))
2597 dfail++;
2598 else if (is_parity_stripe(faila))
2599 failp = faila;
2600
2601 if (is_data_stripe(rbio, failb))
2602 dfail++;
2603 else if (is_parity_stripe(failb))
2604 failp = failb;
2605 /*
2606 * Because we can not use a scrubbing parity to repair the
2607 * data, so the capability of the repair is declined. (In the
2608 * case of RAID5, we can not repair anything.)
2609 */
2610 if (dfail > rbio->bioc->max_errors - 1) {
2611 ret = -EIO;
2612 goto out;
2613 }
2614 /*
2615 * If all data is good, only parity is correctly, just repair
2616 * the parity, no need to recover data stripes.
2617 */
2618 if (dfail == 0)
2619 continue;
2620
2621 /*
2622 * Here means we got one corrupted data stripe and one
2623 * corrupted parity on RAID6, if the corrupted parity is
2624 * scrubbing parity, luckily, use the other one to repair the
2625 * data, or we can not repair the data stripe.
2626 */
2627 if (failp != rbio->scrubp) {
2628 ret = -EIO;
2629 goto out;
2630 }
2631
2632 ret = recover_vertical(rbio, sector_nr, pointers, unmap_array);
2633 if (ret < 0)
2634 goto out;
2635 }
2636out:
2637 kfree(pointers);
2638 kfree(unmap_array);
2639 return ret;
2640}
2641
2642static int scrub_assemble_read_bios(struct btrfs_raid_bio *rbio)
2643{
2644 struct bio_list bio_list = BIO_EMPTY_LIST;
2645 int total_sector_nr;
2646 int ret = 0;
2647
2648 /* Build a list of bios to read all the missing parts. */
2649 for (total_sector_nr = 0; total_sector_nr < rbio->nr_sectors;
2650 total_sector_nr++) {
2651 int sectornr = total_sector_nr % rbio->stripe_nsectors;
2652 int stripe = total_sector_nr / rbio->stripe_nsectors;
2653 struct sector_ptr *sector;
2654
2655 /* No data in the vertical stripe, no need to read. */
2656 if (!test_bit(sectornr, &rbio->dbitmap))
2657 continue;
2658
2659 /*
2660 * We want to find all the sectors missing from the rbio and
2661 * read them from the disk. If sector_in_rbio() finds a sector
2662 * in the bio list we don't need to read it off the stripe.
2663 */
2664 sector = sector_in_rbio(rbio, stripe, sectornr, 1);
2665 if (sector)
2666 continue;
2667
2668 sector = rbio_stripe_sector(rbio, stripe, sectornr);
2669 /*
2670 * The bio cache may have handed us an uptodate sector. If so,
2671 * use it.
2672 */
2673 if (sector->uptodate)
2674 continue;
2675
2676 ret = rbio_add_io_sector(rbio, &bio_list, sector, stripe,
2677 sectornr, REQ_OP_READ);
2678 if (ret) {
2679 bio_list_put(&bio_list);
2680 return ret;
2681 }
2682 }
2683
2684 submit_read_wait_bio_list(rbio, &bio_list);
2685 return 0;
2686}
2687
2688static void scrub_rbio(struct btrfs_raid_bio *rbio)
2689{
2690 int sector_nr;
2691 int ret;
2692
2693 ret = alloc_rbio_essential_pages(rbio);
2694 if (ret)
2695 goto out;
2696
2697 bitmap_clear(rbio->error_bitmap, 0, rbio->nr_sectors);
2698
2699 ret = scrub_assemble_read_bios(rbio);
2700 if (ret < 0)
2701 goto out;
2702
2703 /* We may have some failures, recover the failed sectors first. */
2704 ret = recover_scrub_rbio(rbio);
2705 if (ret < 0)
2706 goto out;
2707
2708 /*
2709 * We have every sector properly prepared. Can finish the scrub
2710 * and writeback the good content.
2711 */
2712 ret = finish_parity_scrub(rbio);
2713 wait_event(rbio->io_wait, atomic_read(&rbio->stripes_pending) == 0);
2714 for (sector_nr = 0; sector_nr < rbio->stripe_nsectors; sector_nr++) {
2715 int found_errors;
2716
2717 found_errors = get_rbio_veritical_errors(rbio, sector_nr, NULL, NULL);
2718 if (found_errors > rbio->bioc->max_errors) {
2719 ret = -EIO;
2720 break;
2721 }
2722 }
2723out:
2724 rbio_orig_end_io(rbio, errno_to_blk_status(ret));
2725}
2726
2727static void scrub_rbio_work_locked(struct work_struct *work)
2728{
2729 scrub_rbio(container_of(work, struct btrfs_raid_bio, work));
2730}
2731
2732void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio)
2733{
2734 if (!lock_stripe_add(rbio))
2735 start_async_work(rbio, scrub_rbio_work_locked);
2736}
2737
2738/*
2739 * This is for scrub call sites where we already have correct data contents.
2740 * This allows us to avoid reading data stripes again.
2741 *
2742 * Unfortunately here we have to do page copy, other than reusing the pages.
2743 * This is due to the fact rbio has its own page management for its cache.
2744 */
2745void raid56_parity_cache_data_pages(struct btrfs_raid_bio *rbio,
2746 struct page **data_pages, u64 data_logical)
2747{
2748 const u64 offset_in_full_stripe = data_logical -
2749 rbio->bioc->full_stripe_logical;
2750 const int page_index = offset_in_full_stripe >> PAGE_SHIFT;
2751 const u32 sectorsize = rbio->bioc->fs_info->sectorsize;
2752 const u32 sectors_per_page = PAGE_SIZE / sectorsize;
2753 int ret;
2754
2755 /*
2756 * If we hit ENOMEM temporarily, but later at
2757 * raid56_parity_submit_scrub_rbio() time it succeeded, we just do
2758 * the extra read, not a big deal.
2759 *
2760 * If we hit ENOMEM later at raid56_parity_submit_scrub_rbio() time,
2761 * the bio would got proper error number set.
2762 */
2763 ret = alloc_rbio_data_pages(rbio);
2764 if (ret < 0)
2765 return;
2766
2767 /* data_logical must be at stripe boundary and inside the full stripe. */
2768 ASSERT(IS_ALIGNED(offset_in_full_stripe, BTRFS_STRIPE_LEN));
2769 ASSERT(offset_in_full_stripe < (rbio->nr_data << BTRFS_STRIPE_LEN_SHIFT));
2770
2771 for (int page_nr = 0; page_nr < (BTRFS_STRIPE_LEN >> PAGE_SHIFT); page_nr++) {
2772 struct page *dst = rbio->stripe_pages[page_nr + page_index];
2773 struct page *src = data_pages[page_nr];
2774
2775 memcpy_page(dst, 0, src, 0, PAGE_SIZE);
2776 for (int sector_nr = sectors_per_page * page_index;
2777 sector_nr < sectors_per_page * (page_index + 1);
2778 sector_nr++)
2779 rbio->stripe_sectors[sector_nr].uptodate = true;
2780 }
2781}