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