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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2011, 2012 STRATO. All rights reserved.
4 */
5
6#include <linux/blkdev.h>
7#include <linux/ratelimit.h>
8#include <linux/sched/mm.h>
9#include "ctree.h"
10#include "volumes.h"
11#include "disk-io.h"
12#include "ordered-data.h"
13#include "transaction.h"
14#include "backref.h"
15#include "extent_io.h"
16#include "dev-replace.h"
17#include "check-integrity.h"
18#include "rcu-string.h"
19#include "raid56.h"
20
21/*
22 * This is only the first step towards a full-features scrub. It reads all
23 * extent and super block and verifies the checksums. In case a bad checksum
24 * is found or the extent cannot be read, good data will be written back if
25 * any can be found.
26 *
27 * Future enhancements:
28 * - In case an unrepairable extent is encountered, track which files are
29 * affected and report them
30 * - track and record media errors, throw out bad devices
31 * - add a mode to also read unallocated space
32 */
33
34struct scrub_block;
35struct scrub_ctx;
36
37/*
38 * the following three values only influence the performance.
39 * The last one configures the number of parallel and outstanding I/O
40 * operations. The first two values configure an upper limit for the number
41 * of (dynamically allocated) pages that are added to a bio.
42 */
43#define SCRUB_PAGES_PER_RD_BIO 32 /* 128k per bio */
44#define SCRUB_PAGES_PER_WR_BIO 32 /* 128k per bio */
45#define SCRUB_BIOS_PER_SCTX 64 /* 8MB per device in flight */
46
47/*
48 * the following value times PAGE_SIZE needs to be large enough to match the
49 * largest node/leaf/sector size that shall be supported.
50 * Values larger than BTRFS_STRIPE_LEN are not supported.
51 */
52#define SCRUB_MAX_PAGES_PER_BLOCK 16 /* 64k per node/leaf/sector */
53
54struct scrub_recover {
55 refcount_t refs;
56 struct btrfs_bio *bbio;
57 u64 map_length;
58};
59
60struct scrub_page {
61 struct scrub_block *sblock;
62 struct page *page;
63 struct btrfs_device *dev;
64 struct list_head list;
65 u64 flags; /* extent flags */
66 u64 generation;
67 u64 logical;
68 u64 physical;
69 u64 physical_for_dev_replace;
70 atomic_t refs;
71 struct {
72 unsigned int mirror_num:8;
73 unsigned int have_csum:1;
74 unsigned int io_error:1;
75 };
76 u8 csum[BTRFS_CSUM_SIZE];
77
78 struct scrub_recover *recover;
79};
80
81struct scrub_bio {
82 int index;
83 struct scrub_ctx *sctx;
84 struct btrfs_device *dev;
85 struct bio *bio;
86 blk_status_t status;
87 u64 logical;
88 u64 physical;
89#if SCRUB_PAGES_PER_WR_BIO >= SCRUB_PAGES_PER_RD_BIO
90 struct scrub_page *pagev[SCRUB_PAGES_PER_WR_BIO];
91#else
92 struct scrub_page *pagev[SCRUB_PAGES_PER_RD_BIO];
93#endif
94 int page_count;
95 int next_free;
96 struct btrfs_work work;
97};
98
99struct scrub_block {
100 struct scrub_page *pagev[SCRUB_MAX_PAGES_PER_BLOCK];
101 int page_count;
102 atomic_t outstanding_pages;
103 refcount_t refs; /* free mem on transition to zero */
104 struct scrub_ctx *sctx;
105 struct scrub_parity *sparity;
106 struct {
107 unsigned int header_error:1;
108 unsigned int checksum_error:1;
109 unsigned int no_io_error_seen:1;
110 unsigned int generation_error:1; /* also sets header_error */
111
112 /* The following is for the data used to check parity */
113 /* It is for the data with checksum */
114 unsigned int data_corrected:1;
115 };
116 struct btrfs_work work;
117};
118
119/* Used for the chunks with parity stripe such RAID5/6 */
120struct scrub_parity {
121 struct scrub_ctx *sctx;
122
123 struct btrfs_device *scrub_dev;
124
125 u64 logic_start;
126
127 u64 logic_end;
128
129 int nsectors;
130
131 u64 stripe_len;
132
133 refcount_t refs;
134
135 struct list_head spages;
136
137 /* Work of parity check and repair */
138 struct btrfs_work work;
139
140 /* Mark the parity blocks which have data */
141 unsigned long *dbitmap;
142
143 /*
144 * Mark the parity blocks which have data, but errors happen when
145 * read data or check data
146 */
147 unsigned long *ebitmap;
148
149 unsigned long bitmap[0];
150};
151
152struct scrub_ctx {
153 struct scrub_bio *bios[SCRUB_BIOS_PER_SCTX];
154 struct btrfs_fs_info *fs_info;
155 int first_free;
156 int curr;
157 atomic_t bios_in_flight;
158 atomic_t workers_pending;
159 spinlock_t list_lock;
160 wait_queue_head_t list_wait;
161 u16 csum_size;
162 struct list_head csum_list;
163 atomic_t cancel_req;
164 int readonly;
165 int pages_per_rd_bio;
166
167 int is_dev_replace;
168
169 struct scrub_bio *wr_curr_bio;
170 struct mutex wr_lock;
171 int pages_per_wr_bio; /* <= SCRUB_PAGES_PER_WR_BIO */
172 struct btrfs_device *wr_tgtdev;
173 bool flush_all_writes;
174
175 /*
176 * statistics
177 */
178 struct btrfs_scrub_progress stat;
179 spinlock_t stat_lock;
180
181 /*
182 * Use a ref counter to avoid use-after-free issues. Scrub workers
183 * decrement bios_in_flight and workers_pending and then do a wakeup
184 * on the list_wait wait queue. We must ensure the main scrub task
185 * doesn't free the scrub context before or while the workers are
186 * doing the wakeup() call.
187 */
188 refcount_t refs;
189};
190
191struct scrub_fixup_nodatasum {
192 struct scrub_ctx *sctx;
193 struct btrfs_device *dev;
194 u64 logical;
195 struct btrfs_root *root;
196 struct btrfs_work work;
197 int mirror_num;
198};
199
200struct scrub_nocow_inode {
201 u64 inum;
202 u64 offset;
203 u64 root;
204 struct list_head list;
205};
206
207struct scrub_copy_nocow_ctx {
208 struct scrub_ctx *sctx;
209 u64 logical;
210 u64 len;
211 int mirror_num;
212 u64 physical_for_dev_replace;
213 struct list_head inodes;
214 struct btrfs_work work;
215};
216
217struct scrub_warning {
218 struct btrfs_path *path;
219 u64 extent_item_size;
220 const char *errstr;
221 u64 physical;
222 u64 logical;
223 struct btrfs_device *dev;
224};
225
226struct full_stripe_lock {
227 struct rb_node node;
228 u64 logical;
229 u64 refs;
230 struct mutex mutex;
231};
232
233static void scrub_pending_bio_inc(struct scrub_ctx *sctx);
234static void scrub_pending_bio_dec(struct scrub_ctx *sctx);
235static void scrub_pending_trans_workers_inc(struct scrub_ctx *sctx);
236static void scrub_pending_trans_workers_dec(struct scrub_ctx *sctx);
237static int scrub_handle_errored_block(struct scrub_block *sblock_to_check);
238static int scrub_setup_recheck_block(struct scrub_block *original_sblock,
239 struct scrub_block *sblocks_for_recheck);
240static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
241 struct scrub_block *sblock,
242 int retry_failed_mirror);
243static void scrub_recheck_block_checksum(struct scrub_block *sblock);
244static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
245 struct scrub_block *sblock_good);
246static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
247 struct scrub_block *sblock_good,
248 int page_num, int force_write);
249static void scrub_write_block_to_dev_replace(struct scrub_block *sblock);
250static int scrub_write_page_to_dev_replace(struct scrub_block *sblock,
251 int page_num);
252static int scrub_checksum_data(struct scrub_block *sblock);
253static int scrub_checksum_tree_block(struct scrub_block *sblock);
254static int scrub_checksum_super(struct scrub_block *sblock);
255static void scrub_block_get(struct scrub_block *sblock);
256static void scrub_block_put(struct scrub_block *sblock);
257static void scrub_page_get(struct scrub_page *spage);
258static void scrub_page_put(struct scrub_page *spage);
259static void scrub_parity_get(struct scrub_parity *sparity);
260static void scrub_parity_put(struct scrub_parity *sparity);
261static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx,
262 struct scrub_page *spage);
263static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
264 u64 physical, struct btrfs_device *dev, u64 flags,
265 u64 gen, int mirror_num, u8 *csum, int force,
266 u64 physical_for_dev_replace);
267static void scrub_bio_end_io(struct bio *bio);
268static void scrub_bio_end_io_worker(struct btrfs_work *work);
269static void scrub_block_complete(struct scrub_block *sblock);
270static void scrub_remap_extent(struct btrfs_fs_info *fs_info,
271 u64 extent_logical, u64 extent_len,
272 u64 *extent_physical,
273 struct btrfs_device **extent_dev,
274 int *extent_mirror_num);
275static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx,
276 struct scrub_page *spage);
277static void scrub_wr_submit(struct scrub_ctx *sctx);
278static void scrub_wr_bio_end_io(struct bio *bio);
279static void scrub_wr_bio_end_io_worker(struct btrfs_work *work);
280static int write_page_nocow(struct scrub_ctx *sctx,
281 u64 physical_for_dev_replace, struct page *page);
282static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root,
283 struct scrub_copy_nocow_ctx *ctx);
284static int copy_nocow_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
285 int mirror_num, u64 physical_for_dev_replace);
286static void copy_nocow_pages_worker(struct btrfs_work *work);
287static void __scrub_blocked_if_needed(struct btrfs_fs_info *fs_info);
288static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info);
289static void scrub_put_ctx(struct scrub_ctx *sctx);
290
291static inline int scrub_is_page_on_raid56(struct scrub_page *page)
292{
293 return page->recover &&
294 (page->recover->bbio->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK);
295}
296
297static void scrub_pending_bio_inc(struct scrub_ctx *sctx)
298{
299 refcount_inc(&sctx->refs);
300 atomic_inc(&sctx->bios_in_flight);
301}
302
303static void scrub_pending_bio_dec(struct scrub_ctx *sctx)
304{
305 atomic_dec(&sctx->bios_in_flight);
306 wake_up(&sctx->list_wait);
307 scrub_put_ctx(sctx);
308}
309
310static void __scrub_blocked_if_needed(struct btrfs_fs_info *fs_info)
311{
312 while (atomic_read(&fs_info->scrub_pause_req)) {
313 mutex_unlock(&fs_info->scrub_lock);
314 wait_event(fs_info->scrub_pause_wait,
315 atomic_read(&fs_info->scrub_pause_req) == 0);
316 mutex_lock(&fs_info->scrub_lock);
317 }
318}
319
320static void scrub_pause_on(struct btrfs_fs_info *fs_info)
321{
322 atomic_inc(&fs_info->scrubs_paused);
323 wake_up(&fs_info->scrub_pause_wait);
324}
325
326static void scrub_pause_off(struct btrfs_fs_info *fs_info)
327{
328 mutex_lock(&fs_info->scrub_lock);
329 __scrub_blocked_if_needed(fs_info);
330 atomic_dec(&fs_info->scrubs_paused);
331 mutex_unlock(&fs_info->scrub_lock);
332
333 wake_up(&fs_info->scrub_pause_wait);
334}
335
336static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info)
337{
338 scrub_pause_on(fs_info);
339 scrub_pause_off(fs_info);
340}
341
342/*
343 * Insert new full stripe lock into full stripe locks tree
344 *
345 * Return pointer to existing or newly inserted full_stripe_lock structure if
346 * everything works well.
347 * Return ERR_PTR(-ENOMEM) if we failed to allocate memory
348 *
349 * NOTE: caller must hold full_stripe_locks_root->lock before calling this
350 * function
351 */
352static struct full_stripe_lock *insert_full_stripe_lock(
353 struct btrfs_full_stripe_locks_tree *locks_root,
354 u64 fstripe_logical)
355{
356 struct rb_node **p;
357 struct rb_node *parent = NULL;
358 struct full_stripe_lock *entry;
359 struct full_stripe_lock *ret;
360
361 lockdep_assert_held(&locks_root->lock);
362
363 p = &locks_root->root.rb_node;
364 while (*p) {
365 parent = *p;
366 entry = rb_entry(parent, struct full_stripe_lock, node);
367 if (fstripe_logical < entry->logical) {
368 p = &(*p)->rb_left;
369 } else if (fstripe_logical > entry->logical) {
370 p = &(*p)->rb_right;
371 } else {
372 entry->refs++;
373 return entry;
374 }
375 }
376
377 /* Insert new lock */
378 ret = kmalloc(sizeof(*ret), GFP_KERNEL);
379 if (!ret)
380 return ERR_PTR(-ENOMEM);
381 ret->logical = fstripe_logical;
382 ret->refs = 1;
383 mutex_init(&ret->mutex);
384
385 rb_link_node(&ret->node, parent, p);
386 rb_insert_color(&ret->node, &locks_root->root);
387 return ret;
388}
389
390/*
391 * Search for a full stripe lock of a block group
392 *
393 * Return pointer to existing full stripe lock if found
394 * Return NULL if not found
395 */
396static struct full_stripe_lock *search_full_stripe_lock(
397 struct btrfs_full_stripe_locks_tree *locks_root,
398 u64 fstripe_logical)
399{
400 struct rb_node *node;
401 struct full_stripe_lock *entry;
402
403 lockdep_assert_held(&locks_root->lock);
404
405 node = locks_root->root.rb_node;
406 while (node) {
407 entry = rb_entry(node, struct full_stripe_lock, node);
408 if (fstripe_logical < entry->logical)
409 node = node->rb_left;
410 else if (fstripe_logical > entry->logical)
411 node = node->rb_right;
412 else
413 return entry;
414 }
415 return NULL;
416}
417
418/*
419 * Helper to get full stripe logical from a normal bytenr.
420 *
421 * Caller must ensure @cache is a RAID56 block group.
422 */
423static u64 get_full_stripe_logical(struct btrfs_block_group_cache *cache,
424 u64 bytenr)
425{
426 u64 ret;
427
428 /*
429 * Due to chunk item size limit, full stripe length should not be
430 * larger than U32_MAX. Just a sanity check here.
431 */
432 WARN_ON_ONCE(cache->full_stripe_len >= U32_MAX);
433
434 /*
435 * round_down() can only handle power of 2, while RAID56 full
436 * stripe length can be 64KiB * n, so we need to manually round down.
437 */
438 ret = div64_u64(bytenr - cache->key.objectid, cache->full_stripe_len) *
439 cache->full_stripe_len + cache->key.objectid;
440 return ret;
441}
442
443/*
444 * Lock a full stripe to avoid concurrency of recovery and read
445 *
446 * It's only used for profiles with parities (RAID5/6), for other profiles it
447 * does nothing.
448 *
449 * Return 0 if we locked full stripe covering @bytenr, with a mutex held.
450 * So caller must call unlock_full_stripe() at the same context.
451 *
452 * Return <0 if encounters error.
453 */
454static int lock_full_stripe(struct btrfs_fs_info *fs_info, u64 bytenr,
455 bool *locked_ret)
456{
457 struct btrfs_block_group_cache *bg_cache;
458 struct btrfs_full_stripe_locks_tree *locks_root;
459 struct full_stripe_lock *existing;
460 u64 fstripe_start;
461 int ret = 0;
462
463 *locked_ret = false;
464 bg_cache = btrfs_lookup_block_group(fs_info, bytenr);
465 if (!bg_cache) {
466 ASSERT(0);
467 return -ENOENT;
468 }
469
470 /* Profiles not based on parity don't need full stripe lock */
471 if (!(bg_cache->flags & BTRFS_BLOCK_GROUP_RAID56_MASK))
472 goto out;
473 locks_root = &bg_cache->full_stripe_locks_root;
474
475 fstripe_start = get_full_stripe_logical(bg_cache, bytenr);
476
477 /* Now insert the full stripe lock */
478 mutex_lock(&locks_root->lock);
479 existing = insert_full_stripe_lock(locks_root, fstripe_start);
480 mutex_unlock(&locks_root->lock);
481 if (IS_ERR(existing)) {
482 ret = PTR_ERR(existing);
483 goto out;
484 }
485 mutex_lock(&existing->mutex);
486 *locked_ret = true;
487out:
488 btrfs_put_block_group(bg_cache);
489 return ret;
490}
491
492/*
493 * Unlock a full stripe.
494 *
495 * NOTE: Caller must ensure it's the same context calling corresponding
496 * lock_full_stripe().
497 *
498 * Return 0 if we unlock full stripe without problem.
499 * Return <0 for error
500 */
501static int unlock_full_stripe(struct btrfs_fs_info *fs_info, u64 bytenr,
502 bool locked)
503{
504 struct btrfs_block_group_cache *bg_cache;
505 struct btrfs_full_stripe_locks_tree *locks_root;
506 struct full_stripe_lock *fstripe_lock;
507 u64 fstripe_start;
508 bool freeit = false;
509 int ret = 0;
510
511 /* If we didn't acquire full stripe lock, no need to continue */
512 if (!locked)
513 return 0;
514
515 bg_cache = btrfs_lookup_block_group(fs_info, bytenr);
516 if (!bg_cache) {
517 ASSERT(0);
518 return -ENOENT;
519 }
520 if (!(bg_cache->flags & BTRFS_BLOCK_GROUP_RAID56_MASK))
521 goto out;
522
523 locks_root = &bg_cache->full_stripe_locks_root;
524 fstripe_start = get_full_stripe_logical(bg_cache, bytenr);
525
526 mutex_lock(&locks_root->lock);
527 fstripe_lock = search_full_stripe_lock(locks_root, fstripe_start);
528 /* Unpaired unlock_full_stripe() detected */
529 if (!fstripe_lock) {
530 WARN_ON(1);
531 ret = -ENOENT;
532 mutex_unlock(&locks_root->lock);
533 goto out;
534 }
535
536 if (fstripe_lock->refs == 0) {
537 WARN_ON(1);
538 btrfs_warn(fs_info, "full stripe lock at %llu refcount underflow",
539 fstripe_lock->logical);
540 } else {
541 fstripe_lock->refs--;
542 }
543
544 if (fstripe_lock->refs == 0) {
545 rb_erase(&fstripe_lock->node, &locks_root->root);
546 freeit = true;
547 }
548 mutex_unlock(&locks_root->lock);
549
550 mutex_unlock(&fstripe_lock->mutex);
551 if (freeit)
552 kfree(fstripe_lock);
553out:
554 btrfs_put_block_group(bg_cache);
555 return ret;
556}
557
558/*
559 * used for workers that require transaction commits (i.e., for the
560 * NOCOW case)
561 */
562static void scrub_pending_trans_workers_inc(struct scrub_ctx *sctx)
563{
564 struct btrfs_fs_info *fs_info = sctx->fs_info;
565
566 refcount_inc(&sctx->refs);
567 /*
568 * increment scrubs_running to prevent cancel requests from
569 * completing as long as a worker is running. we must also
570 * increment scrubs_paused to prevent deadlocking on pause
571 * requests used for transactions commits (as the worker uses a
572 * transaction context). it is safe to regard the worker
573 * as paused for all matters practical. effectively, we only
574 * avoid cancellation requests from completing.
575 */
576 mutex_lock(&fs_info->scrub_lock);
577 atomic_inc(&fs_info->scrubs_running);
578 atomic_inc(&fs_info->scrubs_paused);
579 mutex_unlock(&fs_info->scrub_lock);
580
581 /*
582 * check if @scrubs_running=@scrubs_paused condition
583 * inside wait_event() is not an atomic operation.
584 * which means we may inc/dec @scrub_running/paused
585 * at any time. Let's wake up @scrub_pause_wait as
586 * much as we can to let commit transaction blocked less.
587 */
588 wake_up(&fs_info->scrub_pause_wait);
589
590 atomic_inc(&sctx->workers_pending);
591}
592
593/* used for workers that require transaction commits */
594static void scrub_pending_trans_workers_dec(struct scrub_ctx *sctx)
595{
596 struct btrfs_fs_info *fs_info = sctx->fs_info;
597
598 /*
599 * see scrub_pending_trans_workers_inc() why we're pretending
600 * to be paused in the scrub counters
601 */
602 mutex_lock(&fs_info->scrub_lock);
603 atomic_dec(&fs_info->scrubs_running);
604 atomic_dec(&fs_info->scrubs_paused);
605 mutex_unlock(&fs_info->scrub_lock);
606 atomic_dec(&sctx->workers_pending);
607 wake_up(&fs_info->scrub_pause_wait);
608 wake_up(&sctx->list_wait);
609 scrub_put_ctx(sctx);
610}
611
612static void scrub_free_csums(struct scrub_ctx *sctx)
613{
614 while (!list_empty(&sctx->csum_list)) {
615 struct btrfs_ordered_sum *sum;
616 sum = list_first_entry(&sctx->csum_list,
617 struct btrfs_ordered_sum, list);
618 list_del(&sum->list);
619 kfree(sum);
620 }
621}
622
623static noinline_for_stack void scrub_free_ctx(struct scrub_ctx *sctx)
624{
625 int i;
626
627 if (!sctx)
628 return;
629
630 /* this can happen when scrub is cancelled */
631 if (sctx->curr != -1) {
632 struct scrub_bio *sbio = sctx->bios[sctx->curr];
633
634 for (i = 0; i < sbio->page_count; i++) {
635 WARN_ON(!sbio->pagev[i]->page);
636 scrub_block_put(sbio->pagev[i]->sblock);
637 }
638 bio_put(sbio->bio);
639 }
640
641 for (i = 0; i < SCRUB_BIOS_PER_SCTX; ++i) {
642 struct scrub_bio *sbio = sctx->bios[i];
643
644 if (!sbio)
645 break;
646 kfree(sbio);
647 }
648
649 kfree(sctx->wr_curr_bio);
650 scrub_free_csums(sctx);
651 kfree(sctx);
652}
653
654static void scrub_put_ctx(struct scrub_ctx *sctx)
655{
656 if (refcount_dec_and_test(&sctx->refs))
657 scrub_free_ctx(sctx);
658}
659
660static noinline_for_stack
661struct scrub_ctx *scrub_setup_ctx(struct btrfs_device *dev, int is_dev_replace)
662{
663 struct scrub_ctx *sctx;
664 int i;
665 struct btrfs_fs_info *fs_info = dev->fs_info;
666
667 sctx = kzalloc(sizeof(*sctx), GFP_KERNEL);
668 if (!sctx)
669 goto nomem;
670 refcount_set(&sctx->refs, 1);
671 sctx->is_dev_replace = is_dev_replace;
672 sctx->pages_per_rd_bio = SCRUB_PAGES_PER_RD_BIO;
673 sctx->curr = -1;
674 sctx->fs_info = dev->fs_info;
675 for (i = 0; i < SCRUB_BIOS_PER_SCTX; ++i) {
676 struct scrub_bio *sbio;
677
678 sbio = kzalloc(sizeof(*sbio), GFP_KERNEL);
679 if (!sbio)
680 goto nomem;
681 sctx->bios[i] = sbio;
682
683 sbio->index = i;
684 sbio->sctx = sctx;
685 sbio->page_count = 0;
686 btrfs_init_work(&sbio->work, btrfs_scrub_helper,
687 scrub_bio_end_io_worker, NULL, NULL);
688
689 if (i != SCRUB_BIOS_PER_SCTX - 1)
690 sctx->bios[i]->next_free = i + 1;
691 else
692 sctx->bios[i]->next_free = -1;
693 }
694 sctx->first_free = 0;
695 atomic_set(&sctx->bios_in_flight, 0);
696 atomic_set(&sctx->workers_pending, 0);
697 atomic_set(&sctx->cancel_req, 0);
698 sctx->csum_size = btrfs_super_csum_size(fs_info->super_copy);
699 INIT_LIST_HEAD(&sctx->csum_list);
700
701 spin_lock_init(&sctx->list_lock);
702 spin_lock_init(&sctx->stat_lock);
703 init_waitqueue_head(&sctx->list_wait);
704
705 WARN_ON(sctx->wr_curr_bio != NULL);
706 mutex_init(&sctx->wr_lock);
707 sctx->wr_curr_bio = NULL;
708 if (is_dev_replace) {
709 WARN_ON(!fs_info->dev_replace.tgtdev);
710 sctx->pages_per_wr_bio = SCRUB_PAGES_PER_WR_BIO;
711 sctx->wr_tgtdev = fs_info->dev_replace.tgtdev;
712 sctx->flush_all_writes = false;
713 }
714
715 return sctx;
716
717nomem:
718 scrub_free_ctx(sctx);
719 return ERR_PTR(-ENOMEM);
720}
721
722static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root,
723 void *warn_ctx)
724{
725 u64 isize;
726 u32 nlink;
727 int ret;
728 int i;
729 unsigned nofs_flag;
730 struct extent_buffer *eb;
731 struct btrfs_inode_item *inode_item;
732 struct scrub_warning *swarn = warn_ctx;
733 struct btrfs_fs_info *fs_info = swarn->dev->fs_info;
734 struct inode_fs_paths *ipath = NULL;
735 struct btrfs_root *local_root;
736 struct btrfs_key root_key;
737 struct btrfs_key key;
738
739 root_key.objectid = root;
740 root_key.type = BTRFS_ROOT_ITEM_KEY;
741 root_key.offset = (u64)-1;
742 local_root = btrfs_read_fs_root_no_name(fs_info, &root_key);
743 if (IS_ERR(local_root)) {
744 ret = PTR_ERR(local_root);
745 goto err;
746 }
747
748 /*
749 * this makes the path point to (inum INODE_ITEM ioff)
750 */
751 key.objectid = inum;
752 key.type = BTRFS_INODE_ITEM_KEY;
753 key.offset = 0;
754
755 ret = btrfs_search_slot(NULL, local_root, &key, swarn->path, 0, 0);
756 if (ret) {
757 btrfs_release_path(swarn->path);
758 goto err;
759 }
760
761 eb = swarn->path->nodes[0];
762 inode_item = btrfs_item_ptr(eb, swarn->path->slots[0],
763 struct btrfs_inode_item);
764 isize = btrfs_inode_size(eb, inode_item);
765 nlink = btrfs_inode_nlink(eb, inode_item);
766 btrfs_release_path(swarn->path);
767
768 /*
769 * init_path might indirectly call vmalloc, or use GFP_KERNEL. Scrub
770 * uses GFP_NOFS in this context, so we keep it consistent but it does
771 * not seem to be strictly necessary.
772 */
773 nofs_flag = memalloc_nofs_save();
774 ipath = init_ipath(4096, local_root, swarn->path);
775 memalloc_nofs_restore(nofs_flag);
776 if (IS_ERR(ipath)) {
777 ret = PTR_ERR(ipath);
778 ipath = NULL;
779 goto err;
780 }
781 ret = paths_from_inode(inum, ipath);
782
783 if (ret < 0)
784 goto err;
785
786 /*
787 * we deliberately ignore the bit ipath might have been too small to
788 * hold all of the paths here
789 */
790 for (i = 0; i < ipath->fspath->elem_cnt; ++i)
791 btrfs_warn_in_rcu(fs_info,
792"%s at logical %llu on dev %s, physical %llu, root %llu, inode %llu, offset %llu, length %llu, links %u (path: %s)",
793 swarn->errstr, swarn->logical,
794 rcu_str_deref(swarn->dev->name),
795 swarn->physical,
796 root, inum, offset,
797 min(isize - offset, (u64)PAGE_SIZE), nlink,
798 (char *)(unsigned long)ipath->fspath->val[i]);
799
800 free_ipath(ipath);
801 return 0;
802
803err:
804 btrfs_warn_in_rcu(fs_info,
805 "%s at logical %llu on dev %s, physical %llu, root %llu, inode %llu, offset %llu: path resolving failed with ret=%d",
806 swarn->errstr, swarn->logical,
807 rcu_str_deref(swarn->dev->name),
808 swarn->physical,
809 root, inum, offset, ret);
810
811 free_ipath(ipath);
812 return 0;
813}
814
815static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
816{
817 struct btrfs_device *dev;
818 struct btrfs_fs_info *fs_info;
819 struct btrfs_path *path;
820 struct btrfs_key found_key;
821 struct extent_buffer *eb;
822 struct btrfs_extent_item *ei;
823 struct scrub_warning swarn;
824 unsigned long ptr = 0;
825 u64 extent_item_pos;
826 u64 flags = 0;
827 u64 ref_root;
828 u32 item_size;
829 u8 ref_level = 0;
830 int ret;
831
832 WARN_ON(sblock->page_count < 1);
833 dev = sblock->pagev[0]->dev;
834 fs_info = sblock->sctx->fs_info;
835
836 path = btrfs_alloc_path();
837 if (!path)
838 return;
839
840 swarn.physical = sblock->pagev[0]->physical;
841 swarn.logical = sblock->pagev[0]->logical;
842 swarn.errstr = errstr;
843 swarn.dev = NULL;
844
845 ret = extent_from_logical(fs_info, swarn.logical, path, &found_key,
846 &flags);
847 if (ret < 0)
848 goto out;
849
850 extent_item_pos = swarn.logical - found_key.objectid;
851 swarn.extent_item_size = found_key.offset;
852
853 eb = path->nodes[0];
854 ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
855 item_size = btrfs_item_size_nr(eb, path->slots[0]);
856
857 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
858 do {
859 ret = tree_backref_for_extent(&ptr, eb, &found_key, ei,
860 item_size, &ref_root,
861 &ref_level);
862 btrfs_warn_in_rcu(fs_info,
863"%s at logical %llu on dev %s, physical %llu: metadata %s (level %d) in tree %llu",
864 errstr, swarn.logical,
865 rcu_str_deref(dev->name),
866 swarn.physical,
867 ref_level ? "node" : "leaf",
868 ret < 0 ? -1 : ref_level,
869 ret < 0 ? -1 : ref_root);
870 } while (ret != 1);
871 btrfs_release_path(path);
872 } else {
873 btrfs_release_path(path);
874 swarn.path = path;
875 swarn.dev = dev;
876 iterate_extent_inodes(fs_info, found_key.objectid,
877 extent_item_pos, 1,
878 scrub_print_warning_inode, &swarn, false);
879 }
880
881out:
882 btrfs_free_path(path);
883}
884
885static int scrub_fixup_readpage(u64 inum, u64 offset, u64 root, void *fixup_ctx)
886{
887 struct page *page = NULL;
888 unsigned long index;
889 struct scrub_fixup_nodatasum *fixup = fixup_ctx;
890 int ret;
891 int corrected = 0;
892 struct btrfs_key key;
893 struct inode *inode = NULL;
894 struct btrfs_fs_info *fs_info;
895 u64 end = offset + PAGE_SIZE - 1;
896 struct btrfs_root *local_root;
897 int srcu_index;
898
899 key.objectid = root;
900 key.type = BTRFS_ROOT_ITEM_KEY;
901 key.offset = (u64)-1;
902
903 fs_info = fixup->root->fs_info;
904 srcu_index = srcu_read_lock(&fs_info->subvol_srcu);
905
906 local_root = btrfs_read_fs_root_no_name(fs_info, &key);
907 if (IS_ERR(local_root)) {
908 srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
909 return PTR_ERR(local_root);
910 }
911
912 key.type = BTRFS_INODE_ITEM_KEY;
913 key.objectid = inum;
914 key.offset = 0;
915 inode = btrfs_iget(fs_info->sb, &key, local_root, NULL);
916 srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
917 if (IS_ERR(inode))
918 return PTR_ERR(inode);
919
920 index = offset >> PAGE_SHIFT;
921
922 page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
923 if (!page) {
924 ret = -ENOMEM;
925 goto out;
926 }
927
928 if (PageUptodate(page)) {
929 if (PageDirty(page)) {
930 /*
931 * we need to write the data to the defect sector. the
932 * data that was in that sector is not in memory,
933 * because the page was modified. we must not write the
934 * modified page to that sector.
935 *
936 * TODO: what could be done here: wait for the delalloc
937 * runner to write out that page (might involve
938 * COW) and see whether the sector is still
939 * referenced afterwards.
940 *
941 * For the meantime, we'll treat this error
942 * incorrectable, although there is a chance that a
943 * later scrub will find the bad sector again and that
944 * there's no dirty page in memory, then.
945 */
946 ret = -EIO;
947 goto out;
948 }
949 ret = repair_io_failure(fs_info, inum, offset, PAGE_SIZE,
950 fixup->logical, page,
951 offset - page_offset(page),
952 fixup->mirror_num);
953 unlock_page(page);
954 corrected = !ret;
955 } else {
956 /*
957 * we need to get good data first. the general readpage path
958 * will call repair_io_failure for us, we just have to make
959 * sure we read the bad mirror.
960 */
961 ret = set_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
962 EXTENT_DAMAGED);
963 if (ret) {
964 /* set_extent_bits should give proper error */
965 WARN_ON(ret > 0);
966 if (ret > 0)
967 ret = -EFAULT;
968 goto out;
969 }
970
971 ret = extent_read_full_page(&BTRFS_I(inode)->io_tree, page,
972 btrfs_get_extent,
973 fixup->mirror_num);
974 wait_on_page_locked(page);
975
976 corrected = !test_range_bit(&BTRFS_I(inode)->io_tree, offset,
977 end, EXTENT_DAMAGED, 0, NULL);
978 if (!corrected)
979 clear_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
980 EXTENT_DAMAGED);
981 }
982
983out:
984 if (page)
985 put_page(page);
986
987 iput(inode);
988
989 if (ret < 0)
990 return ret;
991
992 if (ret == 0 && corrected) {
993 /*
994 * we only need to call readpage for one of the inodes belonging
995 * to this extent. so make iterate_extent_inodes stop
996 */
997 return 1;
998 }
999
1000 return -EIO;
1001}
1002
1003static void scrub_fixup_nodatasum(struct btrfs_work *work)
1004{
1005 struct btrfs_fs_info *fs_info;
1006 int ret;
1007 struct scrub_fixup_nodatasum *fixup;
1008 struct scrub_ctx *sctx;
1009 struct btrfs_trans_handle *trans = NULL;
1010 struct btrfs_path *path;
1011 int uncorrectable = 0;
1012
1013 fixup = container_of(work, struct scrub_fixup_nodatasum, work);
1014 sctx = fixup->sctx;
1015 fs_info = fixup->root->fs_info;
1016
1017 path = btrfs_alloc_path();
1018 if (!path) {
1019 spin_lock(&sctx->stat_lock);
1020 ++sctx->stat.malloc_errors;
1021 spin_unlock(&sctx->stat_lock);
1022 uncorrectable = 1;
1023 goto out;
1024 }
1025
1026 trans = btrfs_join_transaction(fixup->root);
1027 if (IS_ERR(trans)) {
1028 uncorrectable = 1;
1029 goto out;
1030 }
1031
1032 /*
1033 * the idea is to trigger a regular read through the standard path. we
1034 * read a page from the (failed) logical address by specifying the
1035 * corresponding copynum of the failed sector. thus, that readpage is
1036 * expected to fail.
1037 * that is the point where on-the-fly error correction will kick in
1038 * (once it's finished) and rewrite the failed sector if a good copy
1039 * can be found.
1040 */
1041 ret = iterate_inodes_from_logical(fixup->logical, fs_info, path,
1042 scrub_fixup_readpage, fixup, false);
1043 if (ret < 0) {
1044 uncorrectable = 1;
1045 goto out;
1046 }
1047 WARN_ON(ret != 1);
1048
1049 spin_lock(&sctx->stat_lock);
1050 ++sctx->stat.corrected_errors;
1051 spin_unlock(&sctx->stat_lock);
1052
1053out:
1054 if (trans && !IS_ERR(trans))
1055 btrfs_end_transaction(trans);
1056 if (uncorrectable) {
1057 spin_lock(&sctx->stat_lock);
1058 ++sctx->stat.uncorrectable_errors;
1059 spin_unlock(&sctx->stat_lock);
1060 btrfs_dev_replace_stats_inc(
1061 &fs_info->dev_replace.num_uncorrectable_read_errors);
1062 btrfs_err_rl_in_rcu(fs_info,
1063 "unable to fixup (nodatasum) error at logical %llu on dev %s",
1064 fixup->logical, rcu_str_deref(fixup->dev->name));
1065 }
1066
1067 btrfs_free_path(path);
1068 kfree(fixup);
1069
1070 scrub_pending_trans_workers_dec(sctx);
1071}
1072
1073static inline void scrub_get_recover(struct scrub_recover *recover)
1074{
1075 refcount_inc(&recover->refs);
1076}
1077
1078static inline void scrub_put_recover(struct btrfs_fs_info *fs_info,
1079 struct scrub_recover *recover)
1080{
1081 if (refcount_dec_and_test(&recover->refs)) {
1082 btrfs_bio_counter_dec(fs_info);
1083 btrfs_put_bbio(recover->bbio);
1084 kfree(recover);
1085 }
1086}
1087
1088/*
1089 * scrub_handle_errored_block gets called when either verification of the
1090 * pages failed or the bio failed to read, e.g. with EIO. In the latter
1091 * case, this function handles all pages in the bio, even though only one
1092 * may be bad.
1093 * The goal of this function is to repair the errored block by using the
1094 * contents of one of the mirrors.
1095 */
1096static int scrub_handle_errored_block(struct scrub_block *sblock_to_check)
1097{
1098 struct scrub_ctx *sctx = sblock_to_check->sctx;
1099 struct btrfs_device *dev;
1100 struct btrfs_fs_info *fs_info;
1101 u64 logical;
1102 unsigned int failed_mirror_index;
1103 unsigned int is_metadata;
1104 unsigned int have_csum;
1105 struct scrub_block *sblocks_for_recheck; /* holds one for each mirror */
1106 struct scrub_block *sblock_bad;
1107 int ret;
1108 int mirror_index;
1109 int page_num;
1110 int success;
1111 bool full_stripe_locked;
1112 static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
1113 DEFAULT_RATELIMIT_BURST);
1114
1115 BUG_ON(sblock_to_check->page_count < 1);
1116 fs_info = sctx->fs_info;
1117 if (sblock_to_check->pagev[0]->flags & BTRFS_EXTENT_FLAG_SUPER) {
1118 /*
1119 * if we find an error in a super block, we just report it.
1120 * They will get written with the next transaction commit
1121 * anyway
1122 */
1123 spin_lock(&sctx->stat_lock);
1124 ++sctx->stat.super_errors;
1125 spin_unlock(&sctx->stat_lock);
1126 return 0;
1127 }
1128 logical = sblock_to_check->pagev[0]->logical;
1129 BUG_ON(sblock_to_check->pagev[0]->mirror_num < 1);
1130 failed_mirror_index = sblock_to_check->pagev[0]->mirror_num - 1;
1131 is_metadata = !(sblock_to_check->pagev[0]->flags &
1132 BTRFS_EXTENT_FLAG_DATA);
1133 have_csum = sblock_to_check->pagev[0]->have_csum;
1134 dev = sblock_to_check->pagev[0]->dev;
1135
1136 /*
1137 * For RAID5/6, race can happen for a different device scrub thread.
1138 * For data corruption, Parity and Data threads will both try
1139 * to recovery the data.
1140 * Race can lead to doubly added csum error, or even unrecoverable
1141 * error.
1142 */
1143 ret = lock_full_stripe(fs_info, logical, &full_stripe_locked);
1144 if (ret < 0) {
1145 spin_lock(&sctx->stat_lock);
1146 if (ret == -ENOMEM)
1147 sctx->stat.malloc_errors++;
1148 sctx->stat.read_errors++;
1149 sctx->stat.uncorrectable_errors++;
1150 spin_unlock(&sctx->stat_lock);
1151 return ret;
1152 }
1153
1154 if (sctx->is_dev_replace && !is_metadata && !have_csum) {
1155 sblocks_for_recheck = NULL;
1156 goto nodatasum_case;
1157 }
1158
1159 /*
1160 * read all mirrors one after the other. This includes to
1161 * re-read the extent or metadata block that failed (that was
1162 * the cause that this fixup code is called) another time,
1163 * page by page this time in order to know which pages
1164 * caused I/O errors and which ones are good (for all mirrors).
1165 * It is the goal to handle the situation when more than one
1166 * mirror contains I/O errors, but the errors do not
1167 * overlap, i.e. the data can be repaired by selecting the
1168 * pages from those mirrors without I/O error on the
1169 * particular pages. One example (with blocks >= 2 * PAGE_SIZE)
1170 * would be that mirror #1 has an I/O error on the first page,
1171 * the second page is good, and mirror #2 has an I/O error on
1172 * the second page, but the first page is good.
1173 * Then the first page of the first mirror can be repaired by
1174 * taking the first page of the second mirror, and the
1175 * second page of the second mirror can be repaired by
1176 * copying the contents of the 2nd page of the 1st mirror.
1177 * One more note: if the pages of one mirror contain I/O
1178 * errors, the checksum cannot be verified. In order to get
1179 * the best data for repairing, the first attempt is to find
1180 * a mirror without I/O errors and with a validated checksum.
1181 * Only if this is not possible, the pages are picked from
1182 * mirrors with I/O errors without considering the checksum.
1183 * If the latter is the case, at the end, the checksum of the
1184 * repaired area is verified in order to correctly maintain
1185 * the statistics.
1186 */
1187
1188 sblocks_for_recheck = kcalloc(BTRFS_MAX_MIRRORS,
1189 sizeof(*sblocks_for_recheck), GFP_NOFS);
1190 if (!sblocks_for_recheck) {
1191 spin_lock(&sctx->stat_lock);
1192 sctx->stat.malloc_errors++;
1193 sctx->stat.read_errors++;
1194 sctx->stat.uncorrectable_errors++;
1195 spin_unlock(&sctx->stat_lock);
1196 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
1197 goto out;
1198 }
1199
1200 /* setup the context, map the logical blocks and alloc the pages */
1201 ret = scrub_setup_recheck_block(sblock_to_check, sblocks_for_recheck);
1202 if (ret) {
1203 spin_lock(&sctx->stat_lock);
1204 sctx->stat.read_errors++;
1205 sctx->stat.uncorrectable_errors++;
1206 spin_unlock(&sctx->stat_lock);
1207 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
1208 goto out;
1209 }
1210 BUG_ON(failed_mirror_index >= BTRFS_MAX_MIRRORS);
1211 sblock_bad = sblocks_for_recheck + failed_mirror_index;
1212
1213 /* build and submit the bios for the failed mirror, check checksums */
1214 scrub_recheck_block(fs_info, sblock_bad, 1);
1215
1216 if (!sblock_bad->header_error && !sblock_bad->checksum_error &&
1217 sblock_bad->no_io_error_seen) {
1218 /*
1219 * the error disappeared after reading page by page, or
1220 * the area was part of a huge bio and other parts of the
1221 * bio caused I/O errors, or the block layer merged several
1222 * read requests into one and the error is caused by a
1223 * different bio (usually one of the two latter cases is
1224 * the cause)
1225 */
1226 spin_lock(&sctx->stat_lock);
1227 sctx->stat.unverified_errors++;
1228 sblock_to_check->data_corrected = 1;
1229 spin_unlock(&sctx->stat_lock);
1230
1231 if (sctx->is_dev_replace)
1232 scrub_write_block_to_dev_replace(sblock_bad);
1233 goto out;
1234 }
1235
1236 if (!sblock_bad->no_io_error_seen) {
1237 spin_lock(&sctx->stat_lock);
1238 sctx->stat.read_errors++;
1239 spin_unlock(&sctx->stat_lock);
1240 if (__ratelimit(&_rs))
1241 scrub_print_warning("i/o error", sblock_to_check);
1242 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
1243 } else if (sblock_bad->checksum_error) {
1244 spin_lock(&sctx->stat_lock);
1245 sctx->stat.csum_errors++;
1246 spin_unlock(&sctx->stat_lock);
1247 if (__ratelimit(&_rs))
1248 scrub_print_warning("checksum error", sblock_to_check);
1249 btrfs_dev_stat_inc_and_print(dev,
1250 BTRFS_DEV_STAT_CORRUPTION_ERRS);
1251 } else if (sblock_bad->header_error) {
1252 spin_lock(&sctx->stat_lock);
1253 sctx->stat.verify_errors++;
1254 spin_unlock(&sctx->stat_lock);
1255 if (__ratelimit(&_rs))
1256 scrub_print_warning("checksum/header error",
1257 sblock_to_check);
1258 if (sblock_bad->generation_error)
1259 btrfs_dev_stat_inc_and_print(dev,
1260 BTRFS_DEV_STAT_GENERATION_ERRS);
1261 else
1262 btrfs_dev_stat_inc_and_print(dev,
1263 BTRFS_DEV_STAT_CORRUPTION_ERRS);
1264 }
1265
1266 if (sctx->readonly) {
1267 ASSERT(!sctx->is_dev_replace);
1268 goto out;
1269 }
1270
1271 if (!is_metadata && !have_csum) {
1272 struct scrub_fixup_nodatasum *fixup_nodatasum;
1273
1274 WARN_ON(sctx->is_dev_replace);
1275
1276nodatasum_case:
1277
1278 /*
1279 * !is_metadata and !have_csum, this means that the data
1280 * might not be COWed, that it might be modified
1281 * concurrently. The general strategy to work on the
1282 * commit root does not help in the case when COW is not
1283 * used.
1284 */
1285 fixup_nodatasum = kzalloc(sizeof(*fixup_nodatasum), GFP_NOFS);
1286 if (!fixup_nodatasum)
1287 goto did_not_correct_error;
1288 fixup_nodatasum->sctx = sctx;
1289 fixup_nodatasum->dev = dev;
1290 fixup_nodatasum->logical = logical;
1291 fixup_nodatasum->root = fs_info->extent_root;
1292 fixup_nodatasum->mirror_num = failed_mirror_index + 1;
1293 scrub_pending_trans_workers_inc(sctx);
1294 btrfs_init_work(&fixup_nodatasum->work, btrfs_scrub_helper,
1295 scrub_fixup_nodatasum, NULL, NULL);
1296 btrfs_queue_work(fs_info->scrub_workers,
1297 &fixup_nodatasum->work);
1298 goto out;
1299 }
1300
1301 /*
1302 * now build and submit the bios for the other mirrors, check
1303 * checksums.
1304 * First try to pick the mirror which is completely without I/O
1305 * errors and also does not have a checksum error.
1306 * If one is found, and if a checksum is present, the full block
1307 * that is known to contain an error is rewritten. Afterwards
1308 * the block is known to be corrected.
1309 * If a mirror is found which is completely correct, and no
1310 * checksum is present, only those pages are rewritten that had
1311 * an I/O error in the block to be repaired, since it cannot be
1312 * determined, which copy of the other pages is better (and it
1313 * could happen otherwise that a correct page would be
1314 * overwritten by a bad one).
1315 */
1316 for (mirror_index = 0; ;mirror_index++) {
1317 struct scrub_block *sblock_other;
1318
1319 if (mirror_index == failed_mirror_index)
1320 continue;
1321
1322 /* raid56's mirror can be more than BTRFS_MAX_MIRRORS */
1323 if (!scrub_is_page_on_raid56(sblock_bad->pagev[0])) {
1324 if (mirror_index >= BTRFS_MAX_MIRRORS)
1325 break;
1326 if (!sblocks_for_recheck[mirror_index].page_count)
1327 break;
1328
1329 sblock_other = sblocks_for_recheck + mirror_index;
1330 } else {
1331 struct scrub_recover *r = sblock_bad->pagev[0]->recover;
1332 int max_allowed = r->bbio->num_stripes -
1333 r->bbio->num_tgtdevs;
1334
1335 if (mirror_index >= max_allowed)
1336 break;
1337 if (!sblocks_for_recheck[1].page_count)
1338 break;
1339
1340 ASSERT(failed_mirror_index == 0);
1341 sblock_other = sblocks_for_recheck + 1;
1342 sblock_other->pagev[0]->mirror_num = 1 + mirror_index;
1343 }
1344
1345 /* build and submit the bios, check checksums */
1346 scrub_recheck_block(fs_info, sblock_other, 0);
1347
1348 if (!sblock_other->header_error &&
1349 !sblock_other->checksum_error &&
1350 sblock_other->no_io_error_seen) {
1351 if (sctx->is_dev_replace) {
1352 scrub_write_block_to_dev_replace(sblock_other);
1353 goto corrected_error;
1354 } else {
1355 ret = scrub_repair_block_from_good_copy(
1356 sblock_bad, sblock_other);
1357 if (!ret)
1358 goto corrected_error;
1359 }
1360 }
1361 }
1362
1363 if (sblock_bad->no_io_error_seen && !sctx->is_dev_replace)
1364 goto did_not_correct_error;
1365
1366 /*
1367 * In case of I/O errors in the area that is supposed to be
1368 * repaired, continue by picking good copies of those pages.
1369 * Select the good pages from mirrors to rewrite bad pages from
1370 * the area to fix. Afterwards verify the checksum of the block
1371 * that is supposed to be repaired. This verification step is
1372 * only done for the purpose of statistic counting and for the
1373 * final scrub report, whether errors remain.
1374 * A perfect algorithm could make use of the checksum and try
1375 * all possible combinations of pages from the different mirrors
1376 * until the checksum verification succeeds. For example, when
1377 * the 2nd page of mirror #1 faces I/O errors, and the 2nd page
1378 * of mirror #2 is readable but the final checksum test fails,
1379 * then the 2nd page of mirror #3 could be tried, whether now
1380 * the final checksum succeeds. But this would be a rare
1381 * exception and is therefore not implemented. At least it is
1382 * avoided that the good copy is overwritten.
1383 * A more useful improvement would be to pick the sectors
1384 * without I/O error based on sector sizes (512 bytes on legacy
1385 * disks) instead of on PAGE_SIZE. Then maybe 512 byte of one
1386 * mirror could be repaired by taking 512 byte of a different
1387 * mirror, even if other 512 byte sectors in the same PAGE_SIZE
1388 * area are unreadable.
1389 */
1390 success = 1;
1391 for (page_num = 0; page_num < sblock_bad->page_count;
1392 page_num++) {
1393 struct scrub_page *page_bad = sblock_bad->pagev[page_num];
1394 struct scrub_block *sblock_other = NULL;
1395
1396 /* skip no-io-error page in scrub */
1397 if (!page_bad->io_error && !sctx->is_dev_replace)
1398 continue;
1399
1400 if (scrub_is_page_on_raid56(sblock_bad->pagev[0])) {
1401 /*
1402 * In case of dev replace, if raid56 rebuild process
1403 * didn't work out correct data, then copy the content
1404 * in sblock_bad to make sure target device is identical
1405 * to source device, instead of writing garbage data in
1406 * sblock_for_recheck array to target device.
1407 */
1408 sblock_other = NULL;
1409 } else if (page_bad->io_error) {
1410 /* try to find no-io-error page in mirrors */
1411 for (mirror_index = 0;
1412 mirror_index < BTRFS_MAX_MIRRORS &&
1413 sblocks_for_recheck[mirror_index].page_count > 0;
1414 mirror_index++) {
1415 if (!sblocks_for_recheck[mirror_index].
1416 pagev[page_num]->io_error) {
1417 sblock_other = sblocks_for_recheck +
1418 mirror_index;
1419 break;
1420 }
1421 }
1422 if (!sblock_other)
1423 success = 0;
1424 }
1425
1426 if (sctx->is_dev_replace) {
1427 /*
1428 * did not find a mirror to fetch the page
1429 * from. scrub_write_page_to_dev_replace()
1430 * handles this case (page->io_error), by
1431 * filling the block with zeros before
1432 * submitting the write request
1433 */
1434 if (!sblock_other)
1435 sblock_other = sblock_bad;
1436
1437 if (scrub_write_page_to_dev_replace(sblock_other,
1438 page_num) != 0) {
1439 btrfs_dev_replace_stats_inc(
1440 &fs_info->dev_replace.num_write_errors);
1441 success = 0;
1442 }
1443 } else if (sblock_other) {
1444 ret = scrub_repair_page_from_good_copy(sblock_bad,
1445 sblock_other,
1446 page_num, 0);
1447 if (0 == ret)
1448 page_bad->io_error = 0;
1449 else
1450 success = 0;
1451 }
1452 }
1453
1454 if (success && !sctx->is_dev_replace) {
1455 if (is_metadata || have_csum) {
1456 /*
1457 * need to verify the checksum now that all
1458 * sectors on disk are repaired (the write
1459 * request for data to be repaired is on its way).
1460 * Just be lazy and use scrub_recheck_block()
1461 * which re-reads the data before the checksum
1462 * is verified, but most likely the data comes out
1463 * of the page cache.
1464 */
1465 scrub_recheck_block(fs_info, sblock_bad, 1);
1466 if (!sblock_bad->header_error &&
1467 !sblock_bad->checksum_error &&
1468 sblock_bad->no_io_error_seen)
1469 goto corrected_error;
1470 else
1471 goto did_not_correct_error;
1472 } else {
1473corrected_error:
1474 spin_lock(&sctx->stat_lock);
1475 sctx->stat.corrected_errors++;
1476 sblock_to_check->data_corrected = 1;
1477 spin_unlock(&sctx->stat_lock);
1478 btrfs_err_rl_in_rcu(fs_info,
1479 "fixed up error at logical %llu on dev %s",
1480 logical, rcu_str_deref(dev->name));
1481 }
1482 } else {
1483did_not_correct_error:
1484 spin_lock(&sctx->stat_lock);
1485 sctx->stat.uncorrectable_errors++;
1486 spin_unlock(&sctx->stat_lock);
1487 btrfs_err_rl_in_rcu(fs_info,
1488 "unable to fixup (regular) error at logical %llu on dev %s",
1489 logical, rcu_str_deref(dev->name));
1490 }
1491
1492out:
1493 if (sblocks_for_recheck) {
1494 for (mirror_index = 0; mirror_index < BTRFS_MAX_MIRRORS;
1495 mirror_index++) {
1496 struct scrub_block *sblock = sblocks_for_recheck +
1497 mirror_index;
1498 struct scrub_recover *recover;
1499 int page_index;
1500
1501 for (page_index = 0; page_index < sblock->page_count;
1502 page_index++) {
1503 sblock->pagev[page_index]->sblock = NULL;
1504 recover = sblock->pagev[page_index]->recover;
1505 if (recover) {
1506 scrub_put_recover(fs_info, recover);
1507 sblock->pagev[page_index]->recover =
1508 NULL;
1509 }
1510 scrub_page_put(sblock->pagev[page_index]);
1511 }
1512 }
1513 kfree(sblocks_for_recheck);
1514 }
1515
1516 ret = unlock_full_stripe(fs_info, logical, full_stripe_locked);
1517 if (ret < 0)
1518 return ret;
1519 return 0;
1520}
1521
1522static inline int scrub_nr_raid_mirrors(struct btrfs_bio *bbio)
1523{
1524 if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID5)
1525 return 2;
1526 else if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID6)
1527 return 3;
1528 else
1529 return (int)bbio->num_stripes;
1530}
1531
1532static inline void scrub_stripe_index_and_offset(u64 logical, u64 map_type,
1533 u64 *raid_map,
1534 u64 mapped_length,
1535 int nstripes, int mirror,
1536 int *stripe_index,
1537 u64 *stripe_offset)
1538{
1539 int i;
1540
1541 if (map_type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
1542 /* RAID5/6 */
1543 for (i = 0; i < nstripes; i++) {
1544 if (raid_map[i] == RAID6_Q_STRIPE ||
1545 raid_map[i] == RAID5_P_STRIPE)
1546 continue;
1547
1548 if (logical >= raid_map[i] &&
1549 logical < raid_map[i] + mapped_length)
1550 break;
1551 }
1552
1553 *stripe_index = i;
1554 *stripe_offset = logical - raid_map[i];
1555 } else {
1556 /* The other RAID type */
1557 *stripe_index = mirror;
1558 *stripe_offset = 0;
1559 }
1560}
1561
1562static int scrub_setup_recheck_block(struct scrub_block *original_sblock,
1563 struct scrub_block *sblocks_for_recheck)
1564{
1565 struct scrub_ctx *sctx = original_sblock->sctx;
1566 struct btrfs_fs_info *fs_info = sctx->fs_info;
1567 u64 length = original_sblock->page_count * PAGE_SIZE;
1568 u64 logical = original_sblock->pagev[0]->logical;
1569 u64 generation = original_sblock->pagev[0]->generation;
1570 u64 flags = original_sblock->pagev[0]->flags;
1571 u64 have_csum = original_sblock->pagev[0]->have_csum;
1572 struct scrub_recover *recover;
1573 struct btrfs_bio *bbio;
1574 u64 sublen;
1575 u64 mapped_length;
1576 u64 stripe_offset;
1577 int stripe_index;
1578 int page_index = 0;
1579 int mirror_index;
1580 int nmirrors;
1581 int ret;
1582
1583 /*
1584 * note: the two members refs and outstanding_pages
1585 * are not used (and not set) in the blocks that are used for
1586 * the recheck procedure
1587 */
1588
1589 while (length > 0) {
1590 sublen = min_t(u64, length, PAGE_SIZE);
1591 mapped_length = sublen;
1592 bbio = NULL;
1593
1594 /*
1595 * with a length of PAGE_SIZE, each returned stripe
1596 * represents one mirror
1597 */
1598 btrfs_bio_counter_inc_blocked(fs_info);
1599 ret = btrfs_map_sblock(fs_info, BTRFS_MAP_GET_READ_MIRRORS,
1600 logical, &mapped_length, &bbio);
1601 if (ret || !bbio || mapped_length < sublen) {
1602 btrfs_put_bbio(bbio);
1603 btrfs_bio_counter_dec(fs_info);
1604 return -EIO;
1605 }
1606
1607 recover = kzalloc(sizeof(struct scrub_recover), GFP_NOFS);
1608 if (!recover) {
1609 btrfs_put_bbio(bbio);
1610 btrfs_bio_counter_dec(fs_info);
1611 return -ENOMEM;
1612 }
1613
1614 refcount_set(&recover->refs, 1);
1615 recover->bbio = bbio;
1616 recover->map_length = mapped_length;
1617
1618 BUG_ON(page_index >= SCRUB_MAX_PAGES_PER_BLOCK);
1619
1620 nmirrors = min(scrub_nr_raid_mirrors(bbio), BTRFS_MAX_MIRRORS);
1621
1622 for (mirror_index = 0; mirror_index < nmirrors;
1623 mirror_index++) {
1624 struct scrub_block *sblock;
1625 struct scrub_page *page;
1626
1627 sblock = sblocks_for_recheck + mirror_index;
1628 sblock->sctx = sctx;
1629
1630 page = kzalloc(sizeof(*page), GFP_NOFS);
1631 if (!page) {
1632leave_nomem:
1633 spin_lock(&sctx->stat_lock);
1634 sctx->stat.malloc_errors++;
1635 spin_unlock(&sctx->stat_lock);
1636 scrub_put_recover(fs_info, recover);
1637 return -ENOMEM;
1638 }
1639 scrub_page_get(page);
1640 sblock->pagev[page_index] = page;
1641 page->sblock = sblock;
1642 page->flags = flags;
1643 page->generation = generation;
1644 page->logical = logical;
1645 page->have_csum = have_csum;
1646 if (have_csum)
1647 memcpy(page->csum,
1648 original_sblock->pagev[0]->csum,
1649 sctx->csum_size);
1650
1651 scrub_stripe_index_and_offset(logical,
1652 bbio->map_type,
1653 bbio->raid_map,
1654 mapped_length,
1655 bbio->num_stripes -
1656 bbio->num_tgtdevs,
1657 mirror_index,
1658 &stripe_index,
1659 &stripe_offset);
1660 page->physical = bbio->stripes[stripe_index].physical +
1661 stripe_offset;
1662 page->dev = bbio->stripes[stripe_index].dev;
1663
1664 BUG_ON(page_index >= original_sblock->page_count);
1665 page->physical_for_dev_replace =
1666 original_sblock->pagev[page_index]->
1667 physical_for_dev_replace;
1668 /* for missing devices, dev->bdev is NULL */
1669 page->mirror_num = mirror_index + 1;
1670 sblock->page_count++;
1671 page->page = alloc_page(GFP_NOFS);
1672 if (!page->page)
1673 goto leave_nomem;
1674
1675 scrub_get_recover(recover);
1676 page->recover = recover;
1677 }
1678 scrub_put_recover(fs_info, recover);
1679 length -= sublen;
1680 logical += sublen;
1681 page_index++;
1682 }
1683
1684 return 0;
1685}
1686
1687static void scrub_bio_wait_endio(struct bio *bio)
1688{
1689 complete(bio->bi_private);
1690}
1691
1692static int scrub_submit_raid56_bio_wait(struct btrfs_fs_info *fs_info,
1693 struct bio *bio,
1694 struct scrub_page *page)
1695{
1696 DECLARE_COMPLETION_ONSTACK(done);
1697 int ret;
1698 int mirror_num;
1699
1700 bio->bi_iter.bi_sector = page->logical >> 9;
1701 bio->bi_private = &done;
1702 bio->bi_end_io = scrub_bio_wait_endio;
1703
1704 mirror_num = page->sblock->pagev[0]->mirror_num;
1705 ret = raid56_parity_recover(fs_info, bio, page->recover->bbio,
1706 page->recover->map_length,
1707 mirror_num, 0);
1708 if (ret)
1709 return ret;
1710
1711 wait_for_completion_io(&done);
1712 return blk_status_to_errno(bio->bi_status);
1713}
1714
1715static void scrub_recheck_block_on_raid56(struct btrfs_fs_info *fs_info,
1716 struct scrub_block *sblock)
1717{
1718 struct scrub_page *first_page = sblock->pagev[0];
1719 struct bio *bio;
1720 int page_num;
1721
1722 /* All pages in sblock belong to the same stripe on the same device. */
1723 ASSERT(first_page->dev);
1724 if (!first_page->dev->bdev)
1725 goto out;
1726
1727 bio = btrfs_io_bio_alloc(BIO_MAX_PAGES);
1728 bio_set_dev(bio, first_page->dev->bdev);
1729
1730 for (page_num = 0; page_num < sblock->page_count; page_num++) {
1731 struct scrub_page *page = sblock->pagev[page_num];
1732
1733 WARN_ON(!page->page);
1734 bio_add_page(bio, page->page, PAGE_SIZE, 0);
1735 }
1736
1737 if (scrub_submit_raid56_bio_wait(fs_info, bio, first_page)) {
1738 bio_put(bio);
1739 goto out;
1740 }
1741
1742 bio_put(bio);
1743
1744 scrub_recheck_block_checksum(sblock);
1745
1746 return;
1747out:
1748 for (page_num = 0; page_num < sblock->page_count; page_num++)
1749 sblock->pagev[page_num]->io_error = 1;
1750
1751 sblock->no_io_error_seen = 0;
1752}
1753
1754/*
1755 * this function will check the on disk data for checksum errors, header
1756 * errors and read I/O errors. If any I/O errors happen, the exact pages
1757 * which are errored are marked as being bad. The goal is to enable scrub
1758 * to take those pages that are not errored from all the mirrors so that
1759 * the pages that are errored in the just handled mirror can be repaired.
1760 */
1761static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
1762 struct scrub_block *sblock,
1763 int retry_failed_mirror)
1764{
1765 int page_num;
1766
1767 sblock->no_io_error_seen = 1;
1768
1769 /* short cut for raid56 */
1770 if (!retry_failed_mirror && scrub_is_page_on_raid56(sblock->pagev[0]))
1771 return scrub_recheck_block_on_raid56(fs_info, sblock);
1772
1773 for (page_num = 0; page_num < sblock->page_count; page_num++) {
1774 struct bio *bio;
1775 struct scrub_page *page = sblock->pagev[page_num];
1776
1777 if (page->dev->bdev == NULL) {
1778 page->io_error = 1;
1779 sblock->no_io_error_seen = 0;
1780 continue;
1781 }
1782
1783 WARN_ON(!page->page);
1784 bio = btrfs_io_bio_alloc(1);
1785 bio_set_dev(bio, page->dev->bdev);
1786
1787 bio_add_page(bio, page->page, PAGE_SIZE, 0);
1788 bio->bi_iter.bi_sector = page->physical >> 9;
1789 bio->bi_opf = REQ_OP_READ;
1790
1791 if (btrfsic_submit_bio_wait(bio)) {
1792 page->io_error = 1;
1793 sblock->no_io_error_seen = 0;
1794 }
1795
1796 bio_put(bio);
1797 }
1798
1799 if (sblock->no_io_error_seen)
1800 scrub_recheck_block_checksum(sblock);
1801}
1802
1803static inline int scrub_check_fsid(u8 fsid[],
1804 struct scrub_page *spage)
1805{
1806 struct btrfs_fs_devices *fs_devices = spage->dev->fs_devices;
1807 int ret;
1808
1809 ret = memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1810 return !ret;
1811}
1812
1813static void scrub_recheck_block_checksum(struct scrub_block *sblock)
1814{
1815 sblock->header_error = 0;
1816 sblock->checksum_error = 0;
1817 sblock->generation_error = 0;
1818
1819 if (sblock->pagev[0]->flags & BTRFS_EXTENT_FLAG_DATA)
1820 scrub_checksum_data(sblock);
1821 else
1822 scrub_checksum_tree_block(sblock);
1823}
1824
1825static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
1826 struct scrub_block *sblock_good)
1827{
1828 int page_num;
1829 int ret = 0;
1830
1831 for (page_num = 0; page_num < sblock_bad->page_count; page_num++) {
1832 int ret_sub;
1833
1834 ret_sub = scrub_repair_page_from_good_copy(sblock_bad,
1835 sblock_good,
1836 page_num, 1);
1837 if (ret_sub)
1838 ret = ret_sub;
1839 }
1840
1841 return ret;
1842}
1843
1844static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
1845 struct scrub_block *sblock_good,
1846 int page_num, int force_write)
1847{
1848 struct scrub_page *page_bad = sblock_bad->pagev[page_num];
1849 struct scrub_page *page_good = sblock_good->pagev[page_num];
1850 struct btrfs_fs_info *fs_info = sblock_bad->sctx->fs_info;
1851
1852 BUG_ON(page_bad->page == NULL);
1853 BUG_ON(page_good->page == NULL);
1854 if (force_write || sblock_bad->header_error ||
1855 sblock_bad->checksum_error || page_bad->io_error) {
1856 struct bio *bio;
1857 int ret;
1858
1859 if (!page_bad->dev->bdev) {
1860 btrfs_warn_rl(fs_info,
1861 "scrub_repair_page_from_good_copy(bdev == NULL) is unexpected");
1862 return -EIO;
1863 }
1864
1865 bio = btrfs_io_bio_alloc(1);
1866 bio_set_dev(bio, page_bad->dev->bdev);
1867 bio->bi_iter.bi_sector = page_bad->physical >> 9;
1868 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
1869
1870 ret = bio_add_page(bio, page_good->page, PAGE_SIZE, 0);
1871 if (PAGE_SIZE != ret) {
1872 bio_put(bio);
1873 return -EIO;
1874 }
1875
1876 if (btrfsic_submit_bio_wait(bio)) {
1877 btrfs_dev_stat_inc_and_print(page_bad->dev,
1878 BTRFS_DEV_STAT_WRITE_ERRS);
1879 btrfs_dev_replace_stats_inc(
1880 &fs_info->dev_replace.num_write_errors);
1881 bio_put(bio);
1882 return -EIO;
1883 }
1884 bio_put(bio);
1885 }
1886
1887 return 0;
1888}
1889
1890static void scrub_write_block_to_dev_replace(struct scrub_block *sblock)
1891{
1892 struct btrfs_fs_info *fs_info = sblock->sctx->fs_info;
1893 int page_num;
1894
1895 /*
1896 * This block is used for the check of the parity on the source device,
1897 * so the data needn't be written into the destination device.
1898 */
1899 if (sblock->sparity)
1900 return;
1901
1902 for (page_num = 0; page_num < sblock->page_count; page_num++) {
1903 int ret;
1904
1905 ret = scrub_write_page_to_dev_replace(sblock, page_num);
1906 if (ret)
1907 btrfs_dev_replace_stats_inc(
1908 &fs_info->dev_replace.num_write_errors);
1909 }
1910}
1911
1912static int scrub_write_page_to_dev_replace(struct scrub_block *sblock,
1913 int page_num)
1914{
1915 struct scrub_page *spage = sblock->pagev[page_num];
1916
1917 BUG_ON(spage->page == NULL);
1918 if (spage->io_error) {
1919 void *mapped_buffer = kmap_atomic(spage->page);
1920
1921 clear_page(mapped_buffer);
1922 flush_dcache_page(spage->page);
1923 kunmap_atomic(mapped_buffer);
1924 }
1925 return scrub_add_page_to_wr_bio(sblock->sctx, spage);
1926}
1927
1928static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx,
1929 struct scrub_page *spage)
1930{
1931 struct scrub_bio *sbio;
1932 int ret;
1933
1934 mutex_lock(&sctx->wr_lock);
1935again:
1936 if (!sctx->wr_curr_bio) {
1937 sctx->wr_curr_bio = kzalloc(sizeof(*sctx->wr_curr_bio),
1938 GFP_KERNEL);
1939 if (!sctx->wr_curr_bio) {
1940 mutex_unlock(&sctx->wr_lock);
1941 return -ENOMEM;
1942 }
1943 sctx->wr_curr_bio->sctx = sctx;
1944 sctx->wr_curr_bio->page_count = 0;
1945 }
1946 sbio = sctx->wr_curr_bio;
1947 if (sbio->page_count == 0) {
1948 struct bio *bio;
1949
1950 sbio->physical = spage->physical_for_dev_replace;
1951 sbio->logical = spage->logical;
1952 sbio->dev = sctx->wr_tgtdev;
1953 bio = sbio->bio;
1954 if (!bio) {
1955 bio = btrfs_io_bio_alloc(sctx->pages_per_wr_bio);
1956 sbio->bio = bio;
1957 }
1958
1959 bio->bi_private = sbio;
1960 bio->bi_end_io = scrub_wr_bio_end_io;
1961 bio_set_dev(bio, sbio->dev->bdev);
1962 bio->bi_iter.bi_sector = sbio->physical >> 9;
1963 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
1964 sbio->status = 0;
1965 } else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
1966 spage->physical_for_dev_replace ||
1967 sbio->logical + sbio->page_count * PAGE_SIZE !=
1968 spage->logical) {
1969 scrub_wr_submit(sctx);
1970 goto again;
1971 }
1972
1973 ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0);
1974 if (ret != PAGE_SIZE) {
1975 if (sbio->page_count < 1) {
1976 bio_put(sbio->bio);
1977 sbio->bio = NULL;
1978 mutex_unlock(&sctx->wr_lock);
1979 return -EIO;
1980 }
1981 scrub_wr_submit(sctx);
1982 goto again;
1983 }
1984
1985 sbio->pagev[sbio->page_count] = spage;
1986 scrub_page_get(spage);
1987 sbio->page_count++;
1988 if (sbio->page_count == sctx->pages_per_wr_bio)
1989 scrub_wr_submit(sctx);
1990 mutex_unlock(&sctx->wr_lock);
1991
1992 return 0;
1993}
1994
1995static void scrub_wr_submit(struct scrub_ctx *sctx)
1996{
1997 struct scrub_bio *sbio;
1998
1999 if (!sctx->wr_curr_bio)
2000 return;
2001
2002 sbio = sctx->wr_curr_bio;
2003 sctx->wr_curr_bio = NULL;
2004 WARN_ON(!sbio->bio->bi_disk);
2005 scrub_pending_bio_inc(sctx);
2006 /* process all writes in a single worker thread. Then the block layer
2007 * orders the requests before sending them to the driver which
2008 * doubled the write performance on spinning disks when measured
2009 * with Linux 3.5 */
2010 btrfsic_submit_bio(sbio->bio);
2011}
2012
2013static void scrub_wr_bio_end_io(struct bio *bio)
2014{
2015 struct scrub_bio *sbio = bio->bi_private;
2016 struct btrfs_fs_info *fs_info = sbio->dev->fs_info;
2017
2018 sbio->status = bio->bi_status;
2019 sbio->bio = bio;
2020
2021 btrfs_init_work(&sbio->work, btrfs_scrubwrc_helper,
2022 scrub_wr_bio_end_io_worker, NULL, NULL);
2023 btrfs_queue_work(fs_info->scrub_wr_completion_workers, &sbio->work);
2024}
2025
2026static void scrub_wr_bio_end_io_worker(struct btrfs_work *work)
2027{
2028 struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
2029 struct scrub_ctx *sctx = sbio->sctx;
2030 int i;
2031
2032 WARN_ON(sbio->page_count > SCRUB_PAGES_PER_WR_BIO);
2033 if (sbio->status) {
2034 struct btrfs_dev_replace *dev_replace =
2035 &sbio->sctx->fs_info->dev_replace;
2036
2037 for (i = 0; i < sbio->page_count; i++) {
2038 struct scrub_page *spage = sbio->pagev[i];
2039
2040 spage->io_error = 1;
2041 btrfs_dev_replace_stats_inc(&dev_replace->
2042 num_write_errors);
2043 }
2044 }
2045
2046 for (i = 0; i < sbio->page_count; i++)
2047 scrub_page_put(sbio->pagev[i]);
2048
2049 bio_put(sbio->bio);
2050 kfree(sbio);
2051 scrub_pending_bio_dec(sctx);
2052}
2053
2054static int scrub_checksum(struct scrub_block *sblock)
2055{
2056 u64 flags;
2057 int ret;
2058
2059 /*
2060 * No need to initialize these stats currently,
2061 * because this function only use return value
2062 * instead of these stats value.
2063 *
2064 * Todo:
2065 * always use stats
2066 */
2067 sblock->header_error = 0;
2068 sblock->generation_error = 0;
2069 sblock->checksum_error = 0;
2070
2071 WARN_ON(sblock->page_count < 1);
2072 flags = sblock->pagev[0]->flags;
2073 ret = 0;
2074 if (flags & BTRFS_EXTENT_FLAG_DATA)
2075 ret = scrub_checksum_data(sblock);
2076 else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
2077 ret = scrub_checksum_tree_block(sblock);
2078 else if (flags & BTRFS_EXTENT_FLAG_SUPER)
2079 (void)scrub_checksum_super(sblock);
2080 else
2081 WARN_ON(1);
2082 if (ret)
2083 scrub_handle_errored_block(sblock);
2084
2085 return ret;
2086}
2087
2088static int scrub_checksum_data(struct scrub_block *sblock)
2089{
2090 struct scrub_ctx *sctx = sblock->sctx;
2091 u8 csum[BTRFS_CSUM_SIZE];
2092 u8 *on_disk_csum;
2093 struct page *page;
2094 void *buffer;
2095 u32 crc = ~(u32)0;
2096 u64 len;
2097 int index;
2098
2099 BUG_ON(sblock->page_count < 1);
2100 if (!sblock->pagev[0]->have_csum)
2101 return 0;
2102
2103 on_disk_csum = sblock->pagev[0]->csum;
2104 page = sblock->pagev[0]->page;
2105 buffer = kmap_atomic(page);
2106
2107 len = sctx->fs_info->sectorsize;
2108 index = 0;
2109 for (;;) {
2110 u64 l = min_t(u64, len, PAGE_SIZE);
2111
2112 crc = btrfs_csum_data(buffer, crc, l);
2113 kunmap_atomic(buffer);
2114 len -= l;
2115 if (len == 0)
2116 break;
2117 index++;
2118 BUG_ON(index >= sblock->page_count);
2119 BUG_ON(!sblock->pagev[index]->page);
2120 page = sblock->pagev[index]->page;
2121 buffer = kmap_atomic(page);
2122 }
2123
2124 btrfs_csum_final(crc, csum);
2125 if (memcmp(csum, on_disk_csum, sctx->csum_size))
2126 sblock->checksum_error = 1;
2127
2128 return sblock->checksum_error;
2129}
2130
2131static int scrub_checksum_tree_block(struct scrub_block *sblock)
2132{
2133 struct scrub_ctx *sctx = sblock->sctx;
2134 struct btrfs_header *h;
2135 struct btrfs_fs_info *fs_info = sctx->fs_info;
2136 u8 calculated_csum[BTRFS_CSUM_SIZE];
2137 u8 on_disk_csum[BTRFS_CSUM_SIZE];
2138 struct page *page;
2139 void *mapped_buffer;
2140 u64 mapped_size;
2141 void *p;
2142 u32 crc = ~(u32)0;
2143 u64 len;
2144 int index;
2145
2146 BUG_ON(sblock->page_count < 1);
2147 page = sblock->pagev[0]->page;
2148 mapped_buffer = kmap_atomic(page);
2149 h = (struct btrfs_header *)mapped_buffer;
2150 memcpy(on_disk_csum, h->csum, sctx->csum_size);
2151
2152 /*
2153 * we don't use the getter functions here, as we
2154 * a) don't have an extent buffer and
2155 * b) the page is already kmapped
2156 */
2157 if (sblock->pagev[0]->logical != btrfs_stack_header_bytenr(h))
2158 sblock->header_error = 1;
2159
2160 if (sblock->pagev[0]->generation != btrfs_stack_header_generation(h)) {
2161 sblock->header_error = 1;
2162 sblock->generation_error = 1;
2163 }
2164
2165 if (!scrub_check_fsid(h->fsid, sblock->pagev[0]))
2166 sblock->header_error = 1;
2167
2168 if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
2169 BTRFS_UUID_SIZE))
2170 sblock->header_error = 1;
2171
2172 len = sctx->fs_info->nodesize - BTRFS_CSUM_SIZE;
2173 mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
2174 p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
2175 index = 0;
2176 for (;;) {
2177 u64 l = min_t(u64, len, mapped_size);
2178
2179 crc = btrfs_csum_data(p, crc, l);
2180 kunmap_atomic(mapped_buffer);
2181 len -= l;
2182 if (len == 0)
2183 break;
2184 index++;
2185 BUG_ON(index >= sblock->page_count);
2186 BUG_ON(!sblock->pagev[index]->page);
2187 page = sblock->pagev[index]->page;
2188 mapped_buffer = kmap_atomic(page);
2189 mapped_size = PAGE_SIZE;
2190 p = mapped_buffer;
2191 }
2192
2193 btrfs_csum_final(crc, calculated_csum);
2194 if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size))
2195 sblock->checksum_error = 1;
2196
2197 return sblock->header_error || sblock->checksum_error;
2198}
2199
2200static int scrub_checksum_super(struct scrub_block *sblock)
2201{
2202 struct btrfs_super_block *s;
2203 struct scrub_ctx *sctx = sblock->sctx;
2204 u8 calculated_csum[BTRFS_CSUM_SIZE];
2205 u8 on_disk_csum[BTRFS_CSUM_SIZE];
2206 struct page *page;
2207 void *mapped_buffer;
2208 u64 mapped_size;
2209 void *p;
2210 u32 crc = ~(u32)0;
2211 int fail_gen = 0;
2212 int fail_cor = 0;
2213 u64 len;
2214 int index;
2215
2216 BUG_ON(sblock->page_count < 1);
2217 page = sblock->pagev[0]->page;
2218 mapped_buffer = kmap_atomic(page);
2219 s = (struct btrfs_super_block *)mapped_buffer;
2220 memcpy(on_disk_csum, s->csum, sctx->csum_size);
2221
2222 if (sblock->pagev[0]->logical != btrfs_super_bytenr(s))
2223 ++fail_cor;
2224
2225 if (sblock->pagev[0]->generation != btrfs_super_generation(s))
2226 ++fail_gen;
2227
2228 if (!scrub_check_fsid(s->fsid, sblock->pagev[0]))
2229 ++fail_cor;
2230
2231 len = BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE;
2232 mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
2233 p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
2234 index = 0;
2235 for (;;) {
2236 u64 l = min_t(u64, len, mapped_size);
2237
2238 crc = btrfs_csum_data(p, crc, l);
2239 kunmap_atomic(mapped_buffer);
2240 len -= l;
2241 if (len == 0)
2242 break;
2243 index++;
2244 BUG_ON(index >= sblock->page_count);
2245 BUG_ON(!sblock->pagev[index]->page);
2246 page = sblock->pagev[index]->page;
2247 mapped_buffer = kmap_atomic(page);
2248 mapped_size = PAGE_SIZE;
2249 p = mapped_buffer;
2250 }
2251
2252 btrfs_csum_final(crc, calculated_csum);
2253 if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size))
2254 ++fail_cor;
2255
2256 if (fail_cor + fail_gen) {
2257 /*
2258 * if we find an error in a super block, we just report it.
2259 * They will get written with the next transaction commit
2260 * anyway
2261 */
2262 spin_lock(&sctx->stat_lock);
2263 ++sctx->stat.super_errors;
2264 spin_unlock(&sctx->stat_lock);
2265 if (fail_cor)
2266 btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev,
2267 BTRFS_DEV_STAT_CORRUPTION_ERRS);
2268 else
2269 btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev,
2270 BTRFS_DEV_STAT_GENERATION_ERRS);
2271 }
2272
2273 return fail_cor + fail_gen;
2274}
2275
2276static void scrub_block_get(struct scrub_block *sblock)
2277{
2278 refcount_inc(&sblock->refs);
2279}
2280
2281static void scrub_block_put(struct scrub_block *sblock)
2282{
2283 if (refcount_dec_and_test(&sblock->refs)) {
2284 int i;
2285
2286 if (sblock->sparity)
2287 scrub_parity_put(sblock->sparity);
2288
2289 for (i = 0; i < sblock->page_count; i++)
2290 scrub_page_put(sblock->pagev[i]);
2291 kfree(sblock);
2292 }
2293}
2294
2295static void scrub_page_get(struct scrub_page *spage)
2296{
2297 atomic_inc(&spage->refs);
2298}
2299
2300static void scrub_page_put(struct scrub_page *spage)
2301{
2302 if (atomic_dec_and_test(&spage->refs)) {
2303 if (spage->page)
2304 __free_page(spage->page);
2305 kfree(spage);
2306 }
2307}
2308
2309static void scrub_submit(struct scrub_ctx *sctx)
2310{
2311 struct scrub_bio *sbio;
2312
2313 if (sctx->curr == -1)
2314 return;
2315
2316 sbio = sctx->bios[sctx->curr];
2317 sctx->curr = -1;
2318 scrub_pending_bio_inc(sctx);
2319 btrfsic_submit_bio(sbio->bio);
2320}
2321
2322static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx,
2323 struct scrub_page *spage)
2324{
2325 struct scrub_block *sblock = spage->sblock;
2326 struct scrub_bio *sbio;
2327 int ret;
2328
2329again:
2330 /*
2331 * grab a fresh bio or wait for one to become available
2332 */
2333 while (sctx->curr == -1) {
2334 spin_lock(&sctx->list_lock);
2335 sctx->curr = sctx->first_free;
2336 if (sctx->curr != -1) {
2337 sctx->first_free = sctx->bios[sctx->curr]->next_free;
2338 sctx->bios[sctx->curr]->next_free = -1;
2339 sctx->bios[sctx->curr]->page_count = 0;
2340 spin_unlock(&sctx->list_lock);
2341 } else {
2342 spin_unlock(&sctx->list_lock);
2343 wait_event(sctx->list_wait, sctx->first_free != -1);
2344 }
2345 }
2346 sbio = sctx->bios[sctx->curr];
2347 if (sbio->page_count == 0) {
2348 struct bio *bio;
2349
2350 sbio->physical = spage->physical;
2351 sbio->logical = spage->logical;
2352 sbio->dev = spage->dev;
2353 bio = sbio->bio;
2354 if (!bio) {
2355 bio = btrfs_io_bio_alloc(sctx->pages_per_rd_bio);
2356 sbio->bio = bio;
2357 }
2358
2359 bio->bi_private = sbio;
2360 bio->bi_end_io = scrub_bio_end_io;
2361 bio_set_dev(bio, sbio->dev->bdev);
2362 bio->bi_iter.bi_sector = sbio->physical >> 9;
2363 bio_set_op_attrs(bio, REQ_OP_READ, 0);
2364 sbio->status = 0;
2365 } else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
2366 spage->physical ||
2367 sbio->logical + sbio->page_count * PAGE_SIZE !=
2368 spage->logical ||
2369 sbio->dev != spage->dev) {
2370 scrub_submit(sctx);
2371 goto again;
2372 }
2373
2374 sbio->pagev[sbio->page_count] = spage;
2375 ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0);
2376 if (ret != PAGE_SIZE) {
2377 if (sbio->page_count < 1) {
2378 bio_put(sbio->bio);
2379 sbio->bio = NULL;
2380 return -EIO;
2381 }
2382 scrub_submit(sctx);
2383 goto again;
2384 }
2385
2386 scrub_block_get(sblock); /* one for the page added to the bio */
2387 atomic_inc(&sblock->outstanding_pages);
2388 sbio->page_count++;
2389 if (sbio->page_count == sctx->pages_per_rd_bio)
2390 scrub_submit(sctx);
2391
2392 return 0;
2393}
2394
2395static void scrub_missing_raid56_end_io(struct bio *bio)
2396{
2397 struct scrub_block *sblock = bio->bi_private;
2398 struct btrfs_fs_info *fs_info = sblock->sctx->fs_info;
2399
2400 if (bio->bi_status)
2401 sblock->no_io_error_seen = 0;
2402
2403 bio_put(bio);
2404
2405 btrfs_queue_work(fs_info->scrub_workers, &sblock->work);
2406}
2407
2408static void scrub_missing_raid56_worker(struct btrfs_work *work)
2409{
2410 struct scrub_block *sblock = container_of(work, struct scrub_block, work);
2411 struct scrub_ctx *sctx = sblock->sctx;
2412 struct btrfs_fs_info *fs_info = sctx->fs_info;
2413 u64 logical;
2414 struct btrfs_device *dev;
2415
2416 logical = sblock->pagev[0]->logical;
2417 dev = sblock->pagev[0]->dev;
2418
2419 if (sblock->no_io_error_seen)
2420 scrub_recheck_block_checksum(sblock);
2421
2422 if (!sblock->no_io_error_seen) {
2423 spin_lock(&sctx->stat_lock);
2424 sctx->stat.read_errors++;
2425 spin_unlock(&sctx->stat_lock);
2426 btrfs_err_rl_in_rcu(fs_info,
2427 "IO error rebuilding logical %llu for dev %s",
2428 logical, rcu_str_deref(dev->name));
2429 } else if (sblock->header_error || sblock->checksum_error) {
2430 spin_lock(&sctx->stat_lock);
2431 sctx->stat.uncorrectable_errors++;
2432 spin_unlock(&sctx->stat_lock);
2433 btrfs_err_rl_in_rcu(fs_info,
2434 "failed to rebuild valid logical %llu for dev %s",
2435 logical, rcu_str_deref(dev->name));
2436 } else {
2437 scrub_write_block_to_dev_replace(sblock);
2438 }
2439
2440 scrub_block_put(sblock);
2441
2442 if (sctx->is_dev_replace && sctx->flush_all_writes) {
2443 mutex_lock(&sctx->wr_lock);
2444 scrub_wr_submit(sctx);
2445 mutex_unlock(&sctx->wr_lock);
2446 }
2447
2448 scrub_pending_bio_dec(sctx);
2449}
2450
2451static void scrub_missing_raid56_pages(struct scrub_block *sblock)
2452{
2453 struct scrub_ctx *sctx = sblock->sctx;
2454 struct btrfs_fs_info *fs_info = sctx->fs_info;
2455 u64 length = sblock->page_count * PAGE_SIZE;
2456 u64 logical = sblock->pagev[0]->logical;
2457 struct btrfs_bio *bbio = NULL;
2458 struct bio *bio;
2459 struct btrfs_raid_bio *rbio;
2460 int ret;
2461 int i;
2462
2463 btrfs_bio_counter_inc_blocked(fs_info);
2464 ret = btrfs_map_sblock(fs_info, BTRFS_MAP_GET_READ_MIRRORS, logical,
2465 &length, &bbio);
2466 if (ret || !bbio || !bbio->raid_map)
2467 goto bbio_out;
2468
2469 if (WARN_ON(!sctx->is_dev_replace ||
2470 !(bbio->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK))) {
2471 /*
2472 * We shouldn't be scrubbing a missing device. Even for dev
2473 * replace, we should only get here for RAID 5/6. We either
2474 * managed to mount something with no mirrors remaining or
2475 * there's a bug in scrub_remap_extent()/btrfs_map_block().
2476 */
2477 goto bbio_out;
2478 }
2479
2480 bio = btrfs_io_bio_alloc(0);
2481 bio->bi_iter.bi_sector = logical >> 9;
2482 bio->bi_private = sblock;
2483 bio->bi_end_io = scrub_missing_raid56_end_io;
2484
2485 rbio = raid56_alloc_missing_rbio(fs_info, bio, bbio, length);
2486 if (!rbio)
2487 goto rbio_out;
2488
2489 for (i = 0; i < sblock->page_count; i++) {
2490 struct scrub_page *spage = sblock->pagev[i];
2491
2492 raid56_add_scrub_pages(rbio, spage->page, spage->logical);
2493 }
2494
2495 btrfs_init_work(&sblock->work, btrfs_scrub_helper,
2496 scrub_missing_raid56_worker, NULL, NULL);
2497 scrub_block_get(sblock);
2498 scrub_pending_bio_inc(sctx);
2499 raid56_submit_missing_rbio(rbio);
2500 return;
2501
2502rbio_out:
2503 bio_put(bio);
2504bbio_out:
2505 btrfs_bio_counter_dec(fs_info);
2506 btrfs_put_bbio(bbio);
2507 spin_lock(&sctx->stat_lock);
2508 sctx->stat.malloc_errors++;
2509 spin_unlock(&sctx->stat_lock);
2510}
2511
2512static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
2513 u64 physical, struct btrfs_device *dev, u64 flags,
2514 u64 gen, int mirror_num, u8 *csum, int force,
2515 u64 physical_for_dev_replace)
2516{
2517 struct scrub_block *sblock;
2518 int index;
2519
2520 sblock = kzalloc(sizeof(*sblock), GFP_KERNEL);
2521 if (!sblock) {
2522 spin_lock(&sctx->stat_lock);
2523 sctx->stat.malloc_errors++;
2524 spin_unlock(&sctx->stat_lock);
2525 return -ENOMEM;
2526 }
2527
2528 /* one ref inside this function, plus one for each page added to
2529 * a bio later on */
2530 refcount_set(&sblock->refs, 1);
2531 sblock->sctx = sctx;
2532 sblock->no_io_error_seen = 1;
2533
2534 for (index = 0; len > 0; index++) {
2535 struct scrub_page *spage;
2536 u64 l = min_t(u64, len, PAGE_SIZE);
2537
2538 spage = kzalloc(sizeof(*spage), GFP_KERNEL);
2539 if (!spage) {
2540leave_nomem:
2541 spin_lock(&sctx->stat_lock);
2542 sctx->stat.malloc_errors++;
2543 spin_unlock(&sctx->stat_lock);
2544 scrub_block_put(sblock);
2545 return -ENOMEM;
2546 }
2547 BUG_ON(index >= SCRUB_MAX_PAGES_PER_BLOCK);
2548 scrub_page_get(spage);
2549 sblock->pagev[index] = spage;
2550 spage->sblock = sblock;
2551 spage->dev = dev;
2552 spage->flags = flags;
2553 spage->generation = gen;
2554 spage->logical = logical;
2555 spage->physical = physical;
2556 spage->physical_for_dev_replace = physical_for_dev_replace;
2557 spage->mirror_num = mirror_num;
2558 if (csum) {
2559 spage->have_csum = 1;
2560 memcpy(spage->csum, csum, sctx->csum_size);
2561 } else {
2562 spage->have_csum = 0;
2563 }
2564 sblock->page_count++;
2565 spage->page = alloc_page(GFP_KERNEL);
2566 if (!spage->page)
2567 goto leave_nomem;
2568 len -= l;
2569 logical += l;
2570 physical += l;
2571 physical_for_dev_replace += l;
2572 }
2573
2574 WARN_ON(sblock->page_count == 0);
2575 if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state)) {
2576 /*
2577 * This case should only be hit for RAID 5/6 device replace. See
2578 * the comment in scrub_missing_raid56_pages() for details.
2579 */
2580 scrub_missing_raid56_pages(sblock);
2581 } else {
2582 for (index = 0; index < sblock->page_count; index++) {
2583 struct scrub_page *spage = sblock->pagev[index];
2584 int ret;
2585
2586 ret = scrub_add_page_to_rd_bio(sctx, spage);
2587 if (ret) {
2588 scrub_block_put(sblock);
2589 return ret;
2590 }
2591 }
2592
2593 if (force)
2594 scrub_submit(sctx);
2595 }
2596
2597 /* last one frees, either here or in bio completion for last page */
2598 scrub_block_put(sblock);
2599 return 0;
2600}
2601
2602static void scrub_bio_end_io(struct bio *bio)
2603{
2604 struct scrub_bio *sbio = bio->bi_private;
2605 struct btrfs_fs_info *fs_info = sbio->dev->fs_info;
2606
2607 sbio->status = bio->bi_status;
2608 sbio->bio = bio;
2609
2610 btrfs_queue_work(fs_info->scrub_workers, &sbio->work);
2611}
2612
2613static void scrub_bio_end_io_worker(struct btrfs_work *work)
2614{
2615 struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
2616 struct scrub_ctx *sctx = sbio->sctx;
2617 int i;
2618
2619 BUG_ON(sbio->page_count > SCRUB_PAGES_PER_RD_BIO);
2620 if (sbio->status) {
2621 for (i = 0; i < sbio->page_count; i++) {
2622 struct scrub_page *spage = sbio->pagev[i];
2623
2624 spage->io_error = 1;
2625 spage->sblock->no_io_error_seen = 0;
2626 }
2627 }
2628
2629 /* now complete the scrub_block items that have all pages completed */
2630 for (i = 0; i < sbio->page_count; i++) {
2631 struct scrub_page *spage = sbio->pagev[i];
2632 struct scrub_block *sblock = spage->sblock;
2633
2634 if (atomic_dec_and_test(&sblock->outstanding_pages))
2635 scrub_block_complete(sblock);
2636 scrub_block_put(sblock);
2637 }
2638
2639 bio_put(sbio->bio);
2640 sbio->bio = NULL;
2641 spin_lock(&sctx->list_lock);
2642 sbio->next_free = sctx->first_free;
2643 sctx->first_free = sbio->index;
2644 spin_unlock(&sctx->list_lock);
2645
2646 if (sctx->is_dev_replace && sctx->flush_all_writes) {
2647 mutex_lock(&sctx->wr_lock);
2648 scrub_wr_submit(sctx);
2649 mutex_unlock(&sctx->wr_lock);
2650 }
2651
2652 scrub_pending_bio_dec(sctx);
2653}
2654
2655static inline void __scrub_mark_bitmap(struct scrub_parity *sparity,
2656 unsigned long *bitmap,
2657 u64 start, u64 len)
2658{
2659 u64 offset;
2660 u64 nsectors64;
2661 u32 nsectors;
2662 int sectorsize = sparity->sctx->fs_info->sectorsize;
2663
2664 if (len >= sparity->stripe_len) {
2665 bitmap_set(bitmap, 0, sparity->nsectors);
2666 return;
2667 }
2668
2669 start -= sparity->logic_start;
2670 start = div64_u64_rem(start, sparity->stripe_len, &offset);
2671 offset = div_u64(offset, sectorsize);
2672 nsectors64 = div_u64(len, sectorsize);
2673
2674 ASSERT(nsectors64 < UINT_MAX);
2675 nsectors = (u32)nsectors64;
2676
2677 if (offset + nsectors <= sparity->nsectors) {
2678 bitmap_set(bitmap, offset, nsectors);
2679 return;
2680 }
2681
2682 bitmap_set(bitmap, offset, sparity->nsectors - offset);
2683 bitmap_set(bitmap, 0, nsectors - (sparity->nsectors - offset));
2684}
2685
2686static inline void scrub_parity_mark_sectors_error(struct scrub_parity *sparity,
2687 u64 start, u64 len)
2688{
2689 __scrub_mark_bitmap(sparity, sparity->ebitmap, start, len);
2690}
2691
2692static inline void scrub_parity_mark_sectors_data(struct scrub_parity *sparity,
2693 u64 start, u64 len)
2694{
2695 __scrub_mark_bitmap(sparity, sparity->dbitmap, start, len);
2696}
2697
2698static void scrub_block_complete(struct scrub_block *sblock)
2699{
2700 int corrupted = 0;
2701
2702 if (!sblock->no_io_error_seen) {
2703 corrupted = 1;
2704 scrub_handle_errored_block(sblock);
2705 } else {
2706 /*
2707 * if has checksum error, write via repair mechanism in
2708 * dev replace case, otherwise write here in dev replace
2709 * case.
2710 */
2711 corrupted = scrub_checksum(sblock);
2712 if (!corrupted && sblock->sctx->is_dev_replace)
2713 scrub_write_block_to_dev_replace(sblock);
2714 }
2715
2716 if (sblock->sparity && corrupted && !sblock->data_corrected) {
2717 u64 start = sblock->pagev[0]->logical;
2718 u64 end = sblock->pagev[sblock->page_count - 1]->logical +
2719 PAGE_SIZE;
2720
2721 scrub_parity_mark_sectors_error(sblock->sparity,
2722 start, end - start);
2723 }
2724}
2725
2726static int scrub_find_csum(struct scrub_ctx *sctx, u64 logical, u8 *csum)
2727{
2728 struct btrfs_ordered_sum *sum = NULL;
2729 unsigned long index;
2730 unsigned long num_sectors;
2731
2732 while (!list_empty(&sctx->csum_list)) {
2733 sum = list_first_entry(&sctx->csum_list,
2734 struct btrfs_ordered_sum, list);
2735 if (sum->bytenr > logical)
2736 return 0;
2737 if (sum->bytenr + sum->len > logical)
2738 break;
2739
2740 ++sctx->stat.csum_discards;
2741 list_del(&sum->list);
2742 kfree(sum);
2743 sum = NULL;
2744 }
2745 if (!sum)
2746 return 0;
2747
2748 index = div_u64(logical - sum->bytenr, sctx->fs_info->sectorsize);
2749 ASSERT(index < UINT_MAX);
2750
2751 num_sectors = sum->len / sctx->fs_info->sectorsize;
2752 memcpy(csum, sum->sums + index, sctx->csum_size);
2753 if (index == num_sectors - 1) {
2754 list_del(&sum->list);
2755 kfree(sum);
2756 }
2757 return 1;
2758}
2759
2760/* scrub extent tries to collect up to 64 kB for each bio */
2761static int scrub_extent(struct scrub_ctx *sctx, struct map_lookup *map,
2762 u64 logical, u64 len,
2763 u64 physical, struct btrfs_device *dev, u64 flags,
2764 u64 gen, int mirror_num, u64 physical_for_dev_replace)
2765{
2766 int ret;
2767 u8 csum[BTRFS_CSUM_SIZE];
2768 u32 blocksize;
2769
2770 if (flags & BTRFS_EXTENT_FLAG_DATA) {
2771 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
2772 blocksize = map->stripe_len;
2773 else
2774 blocksize = sctx->fs_info->sectorsize;
2775 spin_lock(&sctx->stat_lock);
2776 sctx->stat.data_extents_scrubbed++;
2777 sctx->stat.data_bytes_scrubbed += len;
2778 spin_unlock(&sctx->stat_lock);
2779 } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
2780 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
2781 blocksize = map->stripe_len;
2782 else
2783 blocksize = sctx->fs_info->nodesize;
2784 spin_lock(&sctx->stat_lock);
2785 sctx->stat.tree_extents_scrubbed++;
2786 sctx->stat.tree_bytes_scrubbed += len;
2787 spin_unlock(&sctx->stat_lock);
2788 } else {
2789 blocksize = sctx->fs_info->sectorsize;
2790 WARN_ON(1);
2791 }
2792
2793 while (len) {
2794 u64 l = min_t(u64, len, blocksize);
2795 int have_csum = 0;
2796
2797 if (flags & BTRFS_EXTENT_FLAG_DATA) {
2798 /* push csums to sbio */
2799 have_csum = scrub_find_csum(sctx, logical, csum);
2800 if (have_csum == 0)
2801 ++sctx->stat.no_csum;
2802 if (sctx->is_dev_replace && !have_csum) {
2803 ret = copy_nocow_pages(sctx, logical, l,
2804 mirror_num,
2805 physical_for_dev_replace);
2806 goto behind_scrub_pages;
2807 }
2808 }
2809 ret = scrub_pages(sctx, logical, l, physical, dev, flags, gen,
2810 mirror_num, have_csum ? csum : NULL, 0,
2811 physical_for_dev_replace);
2812behind_scrub_pages:
2813 if (ret)
2814 return ret;
2815 len -= l;
2816 logical += l;
2817 physical += l;
2818 physical_for_dev_replace += l;
2819 }
2820 return 0;
2821}
2822
2823static int scrub_pages_for_parity(struct scrub_parity *sparity,
2824 u64 logical, u64 len,
2825 u64 physical, struct btrfs_device *dev,
2826 u64 flags, u64 gen, int mirror_num, u8 *csum)
2827{
2828 struct scrub_ctx *sctx = sparity->sctx;
2829 struct scrub_block *sblock;
2830 int index;
2831
2832 sblock = kzalloc(sizeof(*sblock), GFP_KERNEL);
2833 if (!sblock) {
2834 spin_lock(&sctx->stat_lock);
2835 sctx->stat.malloc_errors++;
2836 spin_unlock(&sctx->stat_lock);
2837 return -ENOMEM;
2838 }
2839
2840 /* one ref inside this function, plus one for each page added to
2841 * a bio later on */
2842 refcount_set(&sblock->refs, 1);
2843 sblock->sctx = sctx;
2844 sblock->no_io_error_seen = 1;
2845 sblock->sparity = sparity;
2846 scrub_parity_get(sparity);
2847
2848 for (index = 0; len > 0; index++) {
2849 struct scrub_page *spage;
2850 u64 l = min_t(u64, len, PAGE_SIZE);
2851
2852 spage = kzalloc(sizeof(*spage), GFP_KERNEL);
2853 if (!spage) {
2854leave_nomem:
2855 spin_lock(&sctx->stat_lock);
2856 sctx->stat.malloc_errors++;
2857 spin_unlock(&sctx->stat_lock);
2858 scrub_block_put(sblock);
2859 return -ENOMEM;
2860 }
2861 BUG_ON(index >= SCRUB_MAX_PAGES_PER_BLOCK);
2862 /* For scrub block */
2863 scrub_page_get(spage);
2864 sblock->pagev[index] = spage;
2865 /* For scrub parity */
2866 scrub_page_get(spage);
2867 list_add_tail(&spage->list, &sparity->spages);
2868 spage->sblock = sblock;
2869 spage->dev = dev;
2870 spage->flags = flags;
2871 spage->generation = gen;
2872 spage->logical = logical;
2873 spage->physical = physical;
2874 spage->mirror_num = mirror_num;
2875 if (csum) {
2876 spage->have_csum = 1;
2877 memcpy(spage->csum, csum, sctx->csum_size);
2878 } else {
2879 spage->have_csum = 0;
2880 }
2881 sblock->page_count++;
2882 spage->page = alloc_page(GFP_KERNEL);
2883 if (!spage->page)
2884 goto leave_nomem;
2885 len -= l;
2886 logical += l;
2887 physical += l;
2888 }
2889
2890 WARN_ON(sblock->page_count == 0);
2891 for (index = 0; index < sblock->page_count; index++) {
2892 struct scrub_page *spage = sblock->pagev[index];
2893 int ret;
2894
2895 ret = scrub_add_page_to_rd_bio(sctx, spage);
2896 if (ret) {
2897 scrub_block_put(sblock);
2898 return ret;
2899 }
2900 }
2901
2902 /* last one frees, either here or in bio completion for last page */
2903 scrub_block_put(sblock);
2904 return 0;
2905}
2906
2907static int scrub_extent_for_parity(struct scrub_parity *sparity,
2908 u64 logical, u64 len,
2909 u64 physical, struct btrfs_device *dev,
2910 u64 flags, u64 gen, int mirror_num)
2911{
2912 struct scrub_ctx *sctx = sparity->sctx;
2913 int ret;
2914 u8 csum[BTRFS_CSUM_SIZE];
2915 u32 blocksize;
2916
2917 if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state)) {
2918 scrub_parity_mark_sectors_error(sparity, logical, len);
2919 return 0;
2920 }
2921
2922 if (flags & BTRFS_EXTENT_FLAG_DATA) {
2923 blocksize = sparity->stripe_len;
2924 } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
2925 blocksize = sparity->stripe_len;
2926 } else {
2927 blocksize = sctx->fs_info->sectorsize;
2928 WARN_ON(1);
2929 }
2930
2931 while (len) {
2932 u64 l = min_t(u64, len, blocksize);
2933 int have_csum = 0;
2934
2935 if (flags & BTRFS_EXTENT_FLAG_DATA) {
2936 /* push csums to sbio */
2937 have_csum = scrub_find_csum(sctx, logical, csum);
2938 if (have_csum == 0)
2939 goto skip;
2940 }
2941 ret = scrub_pages_for_parity(sparity, logical, l, physical, dev,
2942 flags, gen, mirror_num,
2943 have_csum ? csum : NULL);
2944 if (ret)
2945 return ret;
2946skip:
2947 len -= l;
2948 logical += l;
2949 physical += l;
2950 }
2951 return 0;
2952}
2953
2954/*
2955 * Given a physical address, this will calculate it's
2956 * logical offset. if this is a parity stripe, it will return
2957 * the most left data stripe's logical offset.
2958 *
2959 * return 0 if it is a data stripe, 1 means parity stripe.
2960 */
2961static int get_raid56_logic_offset(u64 physical, int num,
2962 struct map_lookup *map, u64 *offset,
2963 u64 *stripe_start)
2964{
2965 int i;
2966 int j = 0;
2967 u64 stripe_nr;
2968 u64 last_offset;
2969 u32 stripe_index;
2970 u32 rot;
2971
2972 last_offset = (physical - map->stripes[num].physical) *
2973 nr_data_stripes(map);
2974 if (stripe_start)
2975 *stripe_start = last_offset;
2976
2977 *offset = last_offset;
2978 for (i = 0; i < nr_data_stripes(map); i++) {
2979 *offset = last_offset + i * map->stripe_len;
2980
2981 stripe_nr = div64_u64(*offset, map->stripe_len);
2982 stripe_nr = div_u64(stripe_nr, nr_data_stripes(map));
2983
2984 /* Work out the disk rotation on this stripe-set */
2985 stripe_nr = div_u64_rem(stripe_nr, map->num_stripes, &rot);
2986 /* calculate which stripe this data locates */
2987 rot += i;
2988 stripe_index = rot % map->num_stripes;
2989 if (stripe_index == num)
2990 return 0;
2991 if (stripe_index < num)
2992 j++;
2993 }
2994 *offset = last_offset + j * map->stripe_len;
2995 return 1;
2996}
2997
2998static void scrub_free_parity(struct scrub_parity *sparity)
2999{
3000 struct scrub_ctx *sctx = sparity->sctx;
3001 struct scrub_page *curr, *next;
3002 int nbits;
3003
3004 nbits = bitmap_weight(sparity->ebitmap, sparity->nsectors);
3005 if (nbits) {
3006 spin_lock(&sctx->stat_lock);
3007 sctx->stat.read_errors += nbits;
3008 sctx->stat.uncorrectable_errors += nbits;
3009 spin_unlock(&sctx->stat_lock);
3010 }
3011
3012 list_for_each_entry_safe(curr, next, &sparity->spages, list) {
3013 list_del_init(&curr->list);
3014 scrub_page_put(curr);
3015 }
3016
3017 kfree(sparity);
3018}
3019
3020static void scrub_parity_bio_endio_worker(struct btrfs_work *work)
3021{
3022 struct scrub_parity *sparity = container_of(work, struct scrub_parity,
3023 work);
3024 struct scrub_ctx *sctx = sparity->sctx;
3025
3026 scrub_free_parity(sparity);
3027 scrub_pending_bio_dec(sctx);
3028}
3029
3030static void scrub_parity_bio_endio(struct bio *bio)
3031{
3032 struct scrub_parity *sparity = (struct scrub_parity *)bio->bi_private;
3033 struct btrfs_fs_info *fs_info = sparity->sctx->fs_info;
3034
3035 if (bio->bi_status)
3036 bitmap_or(sparity->ebitmap, sparity->ebitmap, sparity->dbitmap,
3037 sparity->nsectors);
3038
3039 bio_put(bio);
3040
3041 btrfs_init_work(&sparity->work, btrfs_scrubparity_helper,
3042 scrub_parity_bio_endio_worker, NULL, NULL);
3043 btrfs_queue_work(fs_info->scrub_parity_workers, &sparity->work);
3044}
3045
3046static void scrub_parity_check_and_repair(struct scrub_parity *sparity)
3047{
3048 struct scrub_ctx *sctx = sparity->sctx;
3049 struct btrfs_fs_info *fs_info = sctx->fs_info;
3050 struct bio *bio;
3051 struct btrfs_raid_bio *rbio;
3052 struct btrfs_bio *bbio = NULL;
3053 u64 length;
3054 int ret;
3055
3056 if (!bitmap_andnot(sparity->dbitmap, sparity->dbitmap, sparity->ebitmap,
3057 sparity->nsectors))
3058 goto out;
3059
3060 length = sparity->logic_end - sparity->logic_start;
3061
3062 btrfs_bio_counter_inc_blocked(fs_info);
3063 ret = btrfs_map_sblock(fs_info, BTRFS_MAP_WRITE, sparity->logic_start,
3064 &length, &bbio);
3065 if (ret || !bbio || !bbio->raid_map)
3066 goto bbio_out;
3067
3068 bio = btrfs_io_bio_alloc(0);
3069 bio->bi_iter.bi_sector = sparity->logic_start >> 9;
3070 bio->bi_private = sparity;
3071 bio->bi_end_io = scrub_parity_bio_endio;
3072
3073 rbio = raid56_parity_alloc_scrub_rbio(fs_info, bio, bbio,
3074 length, sparity->scrub_dev,
3075 sparity->dbitmap,
3076 sparity->nsectors);
3077 if (!rbio)
3078 goto rbio_out;
3079
3080 scrub_pending_bio_inc(sctx);
3081 raid56_parity_submit_scrub_rbio(rbio);
3082 return;
3083
3084rbio_out:
3085 bio_put(bio);
3086bbio_out:
3087 btrfs_bio_counter_dec(fs_info);
3088 btrfs_put_bbio(bbio);
3089 bitmap_or(sparity->ebitmap, sparity->ebitmap, sparity->dbitmap,
3090 sparity->nsectors);
3091 spin_lock(&sctx->stat_lock);
3092 sctx->stat.malloc_errors++;
3093 spin_unlock(&sctx->stat_lock);
3094out:
3095 scrub_free_parity(sparity);
3096}
3097
3098static inline int scrub_calc_parity_bitmap_len(int nsectors)
3099{
3100 return DIV_ROUND_UP(nsectors, BITS_PER_LONG) * sizeof(long);
3101}
3102
3103static void scrub_parity_get(struct scrub_parity *sparity)
3104{
3105 refcount_inc(&sparity->refs);
3106}
3107
3108static void scrub_parity_put(struct scrub_parity *sparity)
3109{
3110 if (!refcount_dec_and_test(&sparity->refs))
3111 return;
3112
3113 scrub_parity_check_and_repair(sparity);
3114}
3115
3116static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx,
3117 struct map_lookup *map,
3118 struct btrfs_device *sdev,
3119 struct btrfs_path *path,
3120 u64 logic_start,
3121 u64 logic_end)
3122{
3123 struct btrfs_fs_info *fs_info = sctx->fs_info;
3124 struct btrfs_root *root = fs_info->extent_root;
3125 struct btrfs_root *csum_root = fs_info->csum_root;
3126 struct btrfs_extent_item *extent;
3127 struct btrfs_bio *bbio = NULL;
3128 u64 flags;
3129 int ret;
3130 int slot;
3131 struct extent_buffer *l;
3132 struct btrfs_key key;
3133 u64 generation;
3134 u64 extent_logical;
3135 u64 extent_physical;
3136 u64 extent_len;
3137 u64 mapped_length;
3138 struct btrfs_device *extent_dev;
3139 struct scrub_parity *sparity;
3140 int nsectors;
3141 int bitmap_len;
3142 int extent_mirror_num;
3143 int stop_loop = 0;
3144
3145 nsectors = div_u64(map->stripe_len, fs_info->sectorsize);
3146 bitmap_len = scrub_calc_parity_bitmap_len(nsectors);
3147 sparity = kzalloc(sizeof(struct scrub_parity) + 2 * bitmap_len,
3148 GFP_NOFS);
3149 if (!sparity) {
3150 spin_lock(&sctx->stat_lock);
3151 sctx->stat.malloc_errors++;
3152 spin_unlock(&sctx->stat_lock);
3153 return -ENOMEM;
3154 }
3155
3156 sparity->stripe_len = map->stripe_len;
3157 sparity->nsectors = nsectors;
3158 sparity->sctx = sctx;
3159 sparity->scrub_dev = sdev;
3160 sparity->logic_start = logic_start;
3161 sparity->logic_end = logic_end;
3162 refcount_set(&sparity->refs, 1);
3163 INIT_LIST_HEAD(&sparity->spages);
3164 sparity->dbitmap = sparity->bitmap;
3165 sparity->ebitmap = (void *)sparity->bitmap + bitmap_len;
3166
3167 ret = 0;
3168 while (logic_start < logic_end) {
3169 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
3170 key.type = BTRFS_METADATA_ITEM_KEY;
3171 else
3172 key.type = BTRFS_EXTENT_ITEM_KEY;
3173 key.objectid = logic_start;
3174 key.offset = (u64)-1;
3175
3176 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3177 if (ret < 0)
3178 goto out;
3179
3180 if (ret > 0) {
3181 ret = btrfs_previous_extent_item(root, path, 0);
3182 if (ret < 0)
3183 goto out;
3184 if (ret > 0) {
3185 btrfs_release_path(path);
3186 ret = btrfs_search_slot(NULL, root, &key,
3187 path, 0, 0);
3188 if (ret < 0)
3189 goto out;
3190 }
3191 }
3192
3193 stop_loop = 0;
3194 while (1) {
3195 u64 bytes;
3196
3197 l = path->nodes[0];
3198 slot = path->slots[0];
3199 if (slot >= btrfs_header_nritems(l)) {
3200 ret = btrfs_next_leaf(root, path);
3201 if (ret == 0)
3202 continue;
3203 if (ret < 0)
3204 goto out;
3205
3206 stop_loop = 1;
3207 break;
3208 }
3209 btrfs_item_key_to_cpu(l, &key, slot);
3210
3211 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3212 key.type != BTRFS_METADATA_ITEM_KEY)
3213 goto next;
3214
3215 if (key.type == BTRFS_METADATA_ITEM_KEY)
3216 bytes = fs_info->nodesize;
3217 else
3218 bytes = key.offset;
3219
3220 if (key.objectid + bytes <= logic_start)
3221 goto next;
3222
3223 if (key.objectid >= logic_end) {
3224 stop_loop = 1;
3225 break;
3226 }
3227
3228 while (key.objectid >= logic_start + map->stripe_len)
3229 logic_start += map->stripe_len;
3230
3231 extent = btrfs_item_ptr(l, slot,
3232 struct btrfs_extent_item);
3233 flags = btrfs_extent_flags(l, extent);
3234 generation = btrfs_extent_generation(l, extent);
3235
3236 if ((flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) &&
3237 (key.objectid < logic_start ||
3238 key.objectid + bytes >
3239 logic_start + map->stripe_len)) {
3240 btrfs_err(fs_info,
3241 "scrub: tree block %llu spanning stripes, ignored. logical=%llu",
3242 key.objectid, logic_start);
3243 spin_lock(&sctx->stat_lock);
3244 sctx->stat.uncorrectable_errors++;
3245 spin_unlock(&sctx->stat_lock);
3246 goto next;
3247 }
3248again:
3249 extent_logical = key.objectid;
3250 extent_len = bytes;
3251
3252 if (extent_logical < logic_start) {
3253 extent_len -= logic_start - extent_logical;
3254 extent_logical = logic_start;
3255 }
3256
3257 if (extent_logical + extent_len >
3258 logic_start + map->stripe_len)
3259 extent_len = logic_start + map->stripe_len -
3260 extent_logical;
3261
3262 scrub_parity_mark_sectors_data(sparity, extent_logical,
3263 extent_len);
3264
3265 mapped_length = extent_len;
3266 bbio = NULL;
3267 ret = btrfs_map_block(fs_info, BTRFS_MAP_READ,
3268 extent_logical, &mapped_length, &bbio,
3269 0);
3270 if (!ret) {
3271 if (!bbio || mapped_length < extent_len)
3272 ret = -EIO;
3273 }
3274 if (ret) {
3275 btrfs_put_bbio(bbio);
3276 goto out;
3277 }
3278 extent_physical = bbio->stripes[0].physical;
3279 extent_mirror_num = bbio->mirror_num;
3280 extent_dev = bbio->stripes[0].dev;
3281 btrfs_put_bbio(bbio);
3282
3283 ret = btrfs_lookup_csums_range(csum_root,
3284 extent_logical,
3285 extent_logical + extent_len - 1,
3286 &sctx->csum_list, 1);
3287 if (ret)
3288 goto out;
3289
3290 ret = scrub_extent_for_parity(sparity, extent_logical,
3291 extent_len,
3292 extent_physical,
3293 extent_dev, flags,
3294 generation,
3295 extent_mirror_num);
3296
3297 scrub_free_csums(sctx);
3298
3299 if (ret)
3300 goto out;
3301
3302 if (extent_logical + extent_len <
3303 key.objectid + bytes) {
3304 logic_start += map->stripe_len;
3305
3306 if (logic_start >= logic_end) {
3307 stop_loop = 1;
3308 break;
3309 }
3310
3311 if (logic_start < key.objectid + bytes) {
3312 cond_resched();
3313 goto again;
3314 }
3315 }
3316next:
3317 path->slots[0]++;
3318 }
3319
3320 btrfs_release_path(path);
3321
3322 if (stop_loop)
3323 break;
3324
3325 logic_start += map->stripe_len;
3326 }
3327out:
3328 if (ret < 0)
3329 scrub_parity_mark_sectors_error(sparity, logic_start,
3330 logic_end - logic_start);
3331 scrub_parity_put(sparity);
3332 scrub_submit(sctx);
3333 mutex_lock(&sctx->wr_lock);
3334 scrub_wr_submit(sctx);
3335 mutex_unlock(&sctx->wr_lock);
3336
3337 btrfs_release_path(path);
3338 return ret < 0 ? ret : 0;
3339}
3340
3341static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
3342 struct map_lookup *map,
3343 struct btrfs_device *scrub_dev,
3344 int num, u64 base, u64 length,
3345 int is_dev_replace)
3346{
3347 struct btrfs_path *path, *ppath;
3348 struct btrfs_fs_info *fs_info = sctx->fs_info;
3349 struct btrfs_root *root = fs_info->extent_root;
3350 struct btrfs_root *csum_root = fs_info->csum_root;
3351 struct btrfs_extent_item *extent;
3352 struct blk_plug plug;
3353 u64 flags;
3354 int ret;
3355 int slot;
3356 u64 nstripes;
3357 struct extent_buffer *l;
3358 u64 physical;
3359 u64 logical;
3360 u64 logic_end;
3361 u64 physical_end;
3362 u64 generation;
3363 int mirror_num;
3364 struct reada_control *reada1;
3365 struct reada_control *reada2;
3366 struct btrfs_key key;
3367 struct btrfs_key key_end;
3368 u64 increment = map->stripe_len;
3369 u64 offset;
3370 u64 extent_logical;
3371 u64 extent_physical;
3372 u64 extent_len;
3373 u64 stripe_logical;
3374 u64 stripe_end;
3375 struct btrfs_device *extent_dev;
3376 int extent_mirror_num;
3377 int stop_loop = 0;
3378
3379 physical = map->stripes[num].physical;
3380 offset = 0;
3381 nstripes = div64_u64(length, map->stripe_len);
3382 if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
3383 offset = map->stripe_len * num;
3384 increment = map->stripe_len * map->num_stripes;
3385 mirror_num = 1;
3386 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
3387 int factor = map->num_stripes / map->sub_stripes;
3388 offset = map->stripe_len * (num / map->sub_stripes);
3389 increment = map->stripe_len * factor;
3390 mirror_num = num % map->sub_stripes + 1;
3391 } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
3392 increment = map->stripe_len;
3393 mirror_num = num % map->num_stripes + 1;
3394 } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
3395 increment = map->stripe_len;
3396 mirror_num = num % map->num_stripes + 1;
3397 } else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
3398 get_raid56_logic_offset(physical, num, map, &offset, NULL);
3399 increment = map->stripe_len * nr_data_stripes(map);
3400 mirror_num = 1;
3401 } else {
3402 increment = map->stripe_len;
3403 mirror_num = 1;
3404 }
3405
3406 path = btrfs_alloc_path();
3407 if (!path)
3408 return -ENOMEM;
3409
3410 ppath = btrfs_alloc_path();
3411 if (!ppath) {
3412 btrfs_free_path(path);
3413 return -ENOMEM;
3414 }
3415
3416 /*
3417 * work on commit root. The related disk blocks are static as
3418 * long as COW is applied. This means, it is save to rewrite
3419 * them to repair disk errors without any race conditions
3420 */
3421 path->search_commit_root = 1;
3422 path->skip_locking = 1;
3423
3424 ppath->search_commit_root = 1;
3425 ppath->skip_locking = 1;
3426 /*
3427 * trigger the readahead for extent tree csum tree and wait for
3428 * completion. During readahead, the scrub is officially paused
3429 * to not hold off transaction commits
3430 */
3431 logical = base + offset;
3432 physical_end = physical + nstripes * map->stripe_len;
3433 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
3434 get_raid56_logic_offset(physical_end, num,
3435 map, &logic_end, NULL);
3436 logic_end += base;
3437 } else {
3438 logic_end = logical + increment * nstripes;
3439 }
3440 wait_event(sctx->list_wait,
3441 atomic_read(&sctx->bios_in_flight) == 0);
3442 scrub_blocked_if_needed(fs_info);
3443
3444 /* FIXME it might be better to start readahead at commit root */
3445 key.objectid = logical;
3446 key.type = BTRFS_EXTENT_ITEM_KEY;
3447 key.offset = (u64)0;
3448 key_end.objectid = logic_end;
3449 key_end.type = BTRFS_METADATA_ITEM_KEY;
3450 key_end.offset = (u64)-1;
3451 reada1 = btrfs_reada_add(root, &key, &key_end);
3452
3453 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
3454 key.type = BTRFS_EXTENT_CSUM_KEY;
3455 key.offset = logical;
3456 key_end.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
3457 key_end.type = BTRFS_EXTENT_CSUM_KEY;
3458 key_end.offset = logic_end;
3459 reada2 = btrfs_reada_add(csum_root, &key, &key_end);
3460
3461 if (!IS_ERR(reada1))
3462 btrfs_reada_wait(reada1);
3463 if (!IS_ERR(reada2))
3464 btrfs_reada_wait(reada2);
3465
3466
3467 /*
3468 * collect all data csums for the stripe to avoid seeking during
3469 * the scrub. This might currently (crc32) end up to be about 1MB
3470 */
3471 blk_start_plug(&plug);
3472
3473 /*
3474 * now find all extents for each stripe and scrub them
3475 */
3476 ret = 0;
3477 while (physical < physical_end) {
3478 /*
3479 * canceled?
3480 */
3481 if (atomic_read(&fs_info->scrub_cancel_req) ||
3482 atomic_read(&sctx->cancel_req)) {
3483 ret = -ECANCELED;
3484 goto out;
3485 }
3486 /*
3487 * check to see if we have to pause
3488 */
3489 if (atomic_read(&fs_info->scrub_pause_req)) {
3490 /* push queued extents */
3491 sctx->flush_all_writes = true;
3492 scrub_submit(sctx);
3493 mutex_lock(&sctx->wr_lock);
3494 scrub_wr_submit(sctx);
3495 mutex_unlock(&sctx->wr_lock);
3496 wait_event(sctx->list_wait,
3497 atomic_read(&sctx->bios_in_flight) == 0);
3498 sctx->flush_all_writes = false;
3499 scrub_blocked_if_needed(fs_info);
3500 }
3501
3502 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
3503 ret = get_raid56_logic_offset(physical, num, map,
3504 &logical,
3505 &stripe_logical);
3506 logical += base;
3507 if (ret) {
3508 /* it is parity strip */
3509 stripe_logical += base;
3510 stripe_end = stripe_logical + increment;
3511 ret = scrub_raid56_parity(sctx, map, scrub_dev,
3512 ppath, stripe_logical,
3513 stripe_end);
3514 if (ret)
3515 goto out;
3516 goto skip;
3517 }
3518 }
3519
3520 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
3521 key.type = BTRFS_METADATA_ITEM_KEY;
3522 else
3523 key.type = BTRFS_EXTENT_ITEM_KEY;
3524 key.objectid = logical;
3525 key.offset = (u64)-1;
3526
3527 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3528 if (ret < 0)
3529 goto out;
3530
3531 if (ret > 0) {
3532 ret = btrfs_previous_extent_item(root, path, 0);
3533 if (ret < 0)
3534 goto out;
3535 if (ret > 0) {
3536 /* there's no smaller item, so stick with the
3537 * larger one */
3538 btrfs_release_path(path);
3539 ret = btrfs_search_slot(NULL, root, &key,
3540 path, 0, 0);
3541 if (ret < 0)
3542 goto out;
3543 }
3544 }
3545
3546 stop_loop = 0;
3547 while (1) {
3548 u64 bytes;
3549
3550 l = path->nodes[0];
3551 slot = path->slots[0];
3552 if (slot >= btrfs_header_nritems(l)) {
3553 ret = btrfs_next_leaf(root, path);
3554 if (ret == 0)
3555 continue;
3556 if (ret < 0)
3557 goto out;
3558
3559 stop_loop = 1;
3560 break;
3561 }
3562 btrfs_item_key_to_cpu(l, &key, slot);
3563
3564 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3565 key.type != BTRFS_METADATA_ITEM_KEY)
3566 goto next;
3567
3568 if (key.type == BTRFS_METADATA_ITEM_KEY)
3569 bytes = fs_info->nodesize;
3570 else
3571 bytes = key.offset;
3572
3573 if (key.objectid + bytes <= logical)
3574 goto next;
3575
3576 if (key.objectid >= logical + map->stripe_len) {
3577 /* out of this device extent */
3578 if (key.objectid >= logic_end)
3579 stop_loop = 1;
3580 break;
3581 }
3582
3583 extent = btrfs_item_ptr(l, slot,
3584 struct btrfs_extent_item);
3585 flags = btrfs_extent_flags(l, extent);
3586 generation = btrfs_extent_generation(l, extent);
3587
3588 if ((flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) &&
3589 (key.objectid < logical ||
3590 key.objectid + bytes >
3591 logical + map->stripe_len)) {
3592 btrfs_err(fs_info,
3593 "scrub: tree block %llu spanning stripes, ignored. logical=%llu",
3594 key.objectid, logical);
3595 spin_lock(&sctx->stat_lock);
3596 sctx->stat.uncorrectable_errors++;
3597 spin_unlock(&sctx->stat_lock);
3598 goto next;
3599 }
3600
3601again:
3602 extent_logical = key.objectid;
3603 extent_len = bytes;
3604
3605 /*
3606 * trim extent to this stripe
3607 */
3608 if (extent_logical < logical) {
3609 extent_len -= logical - extent_logical;
3610 extent_logical = logical;
3611 }
3612 if (extent_logical + extent_len >
3613 logical + map->stripe_len) {
3614 extent_len = logical + map->stripe_len -
3615 extent_logical;
3616 }
3617
3618 extent_physical = extent_logical - logical + physical;
3619 extent_dev = scrub_dev;
3620 extent_mirror_num = mirror_num;
3621 if (is_dev_replace)
3622 scrub_remap_extent(fs_info, extent_logical,
3623 extent_len, &extent_physical,
3624 &extent_dev,
3625 &extent_mirror_num);
3626
3627 ret = btrfs_lookup_csums_range(csum_root,
3628 extent_logical,
3629 extent_logical +
3630 extent_len - 1,
3631 &sctx->csum_list, 1);
3632 if (ret)
3633 goto out;
3634
3635 ret = scrub_extent(sctx, map, extent_logical, extent_len,
3636 extent_physical, extent_dev, flags,
3637 generation, extent_mirror_num,
3638 extent_logical - logical + physical);
3639
3640 scrub_free_csums(sctx);
3641
3642 if (ret)
3643 goto out;
3644
3645 if (extent_logical + extent_len <
3646 key.objectid + bytes) {
3647 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
3648 /*
3649 * loop until we find next data stripe
3650 * or we have finished all stripes.
3651 */
3652loop:
3653 physical += map->stripe_len;
3654 ret = get_raid56_logic_offset(physical,
3655 num, map, &logical,
3656 &stripe_logical);
3657 logical += base;
3658
3659 if (ret && physical < physical_end) {
3660 stripe_logical += base;
3661 stripe_end = stripe_logical +
3662 increment;
3663 ret = scrub_raid56_parity(sctx,
3664 map, scrub_dev, ppath,
3665 stripe_logical,
3666 stripe_end);
3667 if (ret)
3668 goto out;
3669 goto loop;
3670 }
3671 } else {
3672 physical += map->stripe_len;
3673 logical += increment;
3674 }
3675 if (logical < key.objectid + bytes) {
3676 cond_resched();
3677 goto again;
3678 }
3679
3680 if (physical >= physical_end) {
3681 stop_loop = 1;
3682 break;
3683 }
3684 }
3685next:
3686 path->slots[0]++;
3687 }
3688 btrfs_release_path(path);
3689skip:
3690 logical += increment;
3691 physical += map->stripe_len;
3692 spin_lock(&sctx->stat_lock);
3693 if (stop_loop)
3694 sctx->stat.last_physical = map->stripes[num].physical +
3695 length;
3696 else
3697 sctx->stat.last_physical = physical;
3698 spin_unlock(&sctx->stat_lock);
3699 if (stop_loop)
3700 break;
3701 }
3702out:
3703 /* push queued extents */
3704 scrub_submit(sctx);
3705 mutex_lock(&sctx->wr_lock);
3706 scrub_wr_submit(sctx);
3707 mutex_unlock(&sctx->wr_lock);
3708
3709 blk_finish_plug(&plug);
3710 btrfs_free_path(path);
3711 btrfs_free_path(ppath);
3712 return ret < 0 ? ret : 0;
3713}
3714
3715static noinline_for_stack int scrub_chunk(struct scrub_ctx *sctx,
3716 struct btrfs_device *scrub_dev,
3717 u64 chunk_offset, u64 length,
3718 u64 dev_offset,
3719 struct btrfs_block_group_cache *cache,
3720 int is_dev_replace)
3721{
3722 struct btrfs_fs_info *fs_info = sctx->fs_info;
3723 struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
3724 struct map_lookup *map;
3725 struct extent_map *em;
3726 int i;
3727 int ret = 0;
3728
3729 read_lock(&map_tree->map_tree.lock);
3730 em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
3731 read_unlock(&map_tree->map_tree.lock);
3732
3733 if (!em) {
3734 /*
3735 * Might have been an unused block group deleted by the cleaner
3736 * kthread or relocation.
3737 */
3738 spin_lock(&cache->lock);
3739 if (!cache->removed)
3740 ret = -EINVAL;
3741 spin_unlock(&cache->lock);
3742
3743 return ret;
3744 }
3745
3746 map = em->map_lookup;
3747 if (em->start != chunk_offset)
3748 goto out;
3749
3750 if (em->len < length)
3751 goto out;
3752
3753 for (i = 0; i < map->num_stripes; ++i) {
3754 if (map->stripes[i].dev->bdev == scrub_dev->bdev &&
3755 map->stripes[i].physical == dev_offset) {
3756 ret = scrub_stripe(sctx, map, scrub_dev, i,
3757 chunk_offset, length,
3758 is_dev_replace);
3759 if (ret)
3760 goto out;
3761 }
3762 }
3763out:
3764 free_extent_map(em);
3765
3766 return ret;
3767}
3768
3769static noinline_for_stack
3770int scrub_enumerate_chunks(struct scrub_ctx *sctx,
3771 struct btrfs_device *scrub_dev, u64 start, u64 end,
3772 int is_dev_replace)
3773{
3774 struct btrfs_dev_extent *dev_extent = NULL;
3775 struct btrfs_path *path;
3776 struct btrfs_fs_info *fs_info = sctx->fs_info;
3777 struct btrfs_root *root = fs_info->dev_root;
3778 u64 length;
3779 u64 chunk_offset;
3780 int ret = 0;
3781 int ro_set;
3782 int slot;
3783 struct extent_buffer *l;
3784 struct btrfs_key key;
3785 struct btrfs_key found_key;
3786 struct btrfs_block_group_cache *cache;
3787 struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
3788
3789 path = btrfs_alloc_path();
3790 if (!path)
3791 return -ENOMEM;
3792
3793 path->reada = READA_FORWARD;
3794 path->search_commit_root = 1;
3795 path->skip_locking = 1;
3796
3797 key.objectid = scrub_dev->devid;
3798 key.offset = 0ull;
3799 key.type = BTRFS_DEV_EXTENT_KEY;
3800
3801 while (1) {
3802 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3803 if (ret < 0)
3804 break;
3805 if (ret > 0) {
3806 if (path->slots[0] >=
3807 btrfs_header_nritems(path->nodes[0])) {
3808 ret = btrfs_next_leaf(root, path);
3809 if (ret < 0)
3810 break;
3811 if (ret > 0) {
3812 ret = 0;
3813 break;
3814 }
3815 } else {
3816 ret = 0;
3817 }
3818 }
3819
3820 l = path->nodes[0];
3821 slot = path->slots[0];
3822
3823 btrfs_item_key_to_cpu(l, &found_key, slot);
3824
3825 if (found_key.objectid != scrub_dev->devid)
3826 break;
3827
3828 if (found_key.type != BTRFS_DEV_EXTENT_KEY)
3829 break;
3830
3831 if (found_key.offset >= end)
3832 break;
3833
3834 if (found_key.offset < key.offset)
3835 break;
3836
3837 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
3838 length = btrfs_dev_extent_length(l, dev_extent);
3839
3840 if (found_key.offset + length <= start)
3841 goto skip;
3842
3843 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
3844
3845 /*
3846 * get a reference on the corresponding block group to prevent
3847 * the chunk from going away while we scrub it
3848 */
3849 cache = btrfs_lookup_block_group(fs_info, chunk_offset);
3850
3851 /* some chunks are removed but not committed to disk yet,
3852 * continue scrubbing */
3853 if (!cache)
3854 goto skip;
3855
3856 /*
3857 * we need call btrfs_inc_block_group_ro() with scrubs_paused,
3858 * to avoid deadlock caused by:
3859 * btrfs_inc_block_group_ro()
3860 * -> btrfs_wait_for_commit()
3861 * -> btrfs_commit_transaction()
3862 * -> btrfs_scrub_pause()
3863 */
3864 scrub_pause_on(fs_info);
3865 ret = btrfs_inc_block_group_ro(fs_info, cache);
3866 if (!ret && is_dev_replace) {
3867 /*
3868 * If we are doing a device replace wait for any tasks
3869 * that started dellaloc right before we set the block
3870 * group to RO mode, as they might have just allocated
3871 * an extent from it or decided they could do a nocow
3872 * write. And if any such tasks did that, wait for their
3873 * ordered extents to complete and then commit the
3874 * current transaction, so that we can later see the new
3875 * extent items in the extent tree - the ordered extents
3876 * create delayed data references (for cow writes) when
3877 * they complete, which will be run and insert the
3878 * corresponding extent items into the extent tree when
3879 * we commit the transaction they used when running
3880 * inode.c:btrfs_finish_ordered_io(). We later use
3881 * the commit root of the extent tree to find extents
3882 * to copy from the srcdev into the tgtdev, and we don't
3883 * want to miss any new extents.
3884 */
3885 btrfs_wait_block_group_reservations(cache);
3886 btrfs_wait_nocow_writers(cache);
3887 ret = btrfs_wait_ordered_roots(fs_info, U64_MAX,
3888 cache->key.objectid,
3889 cache->key.offset);
3890 if (ret > 0) {
3891 struct btrfs_trans_handle *trans;
3892
3893 trans = btrfs_join_transaction(root);
3894 if (IS_ERR(trans))
3895 ret = PTR_ERR(trans);
3896 else
3897 ret = btrfs_commit_transaction(trans);
3898 if (ret) {
3899 scrub_pause_off(fs_info);
3900 btrfs_put_block_group(cache);
3901 break;
3902 }
3903 }
3904 }
3905 scrub_pause_off(fs_info);
3906
3907 if (ret == 0) {
3908 ro_set = 1;
3909 } else if (ret == -ENOSPC) {
3910 /*
3911 * btrfs_inc_block_group_ro return -ENOSPC when it
3912 * failed in creating new chunk for metadata.
3913 * It is not a problem for scrub/replace, because
3914 * metadata are always cowed, and our scrub paused
3915 * commit_transactions.
3916 */
3917 ro_set = 0;
3918 } else {
3919 btrfs_warn(fs_info,
3920 "failed setting block group ro: %d", ret);
3921 btrfs_put_block_group(cache);
3922 break;
3923 }
3924
3925 btrfs_dev_replace_write_lock(&fs_info->dev_replace);
3926 dev_replace->cursor_right = found_key.offset + length;
3927 dev_replace->cursor_left = found_key.offset;
3928 dev_replace->item_needs_writeback = 1;
3929 btrfs_dev_replace_write_unlock(&fs_info->dev_replace);
3930 ret = scrub_chunk(sctx, scrub_dev, chunk_offset, length,
3931 found_key.offset, cache, is_dev_replace);
3932
3933 /*
3934 * flush, submit all pending read and write bios, afterwards
3935 * wait for them.
3936 * Note that in the dev replace case, a read request causes
3937 * write requests that are submitted in the read completion
3938 * worker. Therefore in the current situation, it is required
3939 * that all write requests are flushed, so that all read and
3940 * write requests are really completed when bios_in_flight
3941 * changes to 0.
3942 */
3943 sctx->flush_all_writes = true;
3944 scrub_submit(sctx);
3945 mutex_lock(&sctx->wr_lock);
3946 scrub_wr_submit(sctx);
3947 mutex_unlock(&sctx->wr_lock);
3948
3949 wait_event(sctx->list_wait,
3950 atomic_read(&sctx->bios_in_flight) == 0);
3951
3952 scrub_pause_on(fs_info);
3953
3954 /*
3955 * must be called before we decrease @scrub_paused.
3956 * make sure we don't block transaction commit while
3957 * we are waiting pending workers finished.
3958 */
3959 wait_event(sctx->list_wait,
3960 atomic_read(&sctx->workers_pending) == 0);
3961 sctx->flush_all_writes = false;
3962
3963 scrub_pause_off(fs_info);
3964
3965 btrfs_dev_replace_write_lock(&fs_info->dev_replace);
3966 dev_replace->cursor_left = dev_replace->cursor_right;
3967 dev_replace->item_needs_writeback = 1;
3968 btrfs_dev_replace_write_unlock(&fs_info->dev_replace);
3969
3970 if (ro_set)
3971 btrfs_dec_block_group_ro(cache);
3972
3973 /*
3974 * We might have prevented the cleaner kthread from deleting
3975 * this block group if it was already unused because we raced
3976 * and set it to RO mode first. So add it back to the unused
3977 * list, otherwise it might not ever be deleted unless a manual
3978 * balance is triggered or it becomes used and unused again.
3979 */
3980 spin_lock(&cache->lock);
3981 if (!cache->removed && !cache->ro && cache->reserved == 0 &&
3982 btrfs_block_group_used(&cache->item) == 0) {
3983 spin_unlock(&cache->lock);
3984 spin_lock(&fs_info->unused_bgs_lock);
3985 if (list_empty(&cache->bg_list)) {
3986 btrfs_get_block_group(cache);
3987 list_add_tail(&cache->bg_list,
3988 &fs_info->unused_bgs);
3989 }
3990 spin_unlock(&fs_info->unused_bgs_lock);
3991 } else {
3992 spin_unlock(&cache->lock);
3993 }
3994
3995 btrfs_put_block_group(cache);
3996 if (ret)
3997 break;
3998 if (is_dev_replace &&
3999 atomic64_read(&dev_replace->num_write_errors) > 0) {
4000 ret = -EIO;
4001 break;
4002 }
4003 if (sctx->stat.malloc_errors > 0) {
4004 ret = -ENOMEM;
4005 break;
4006 }
4007skip:
4008 key.offset = found_key.offset + length;
4009 btrfs_release_path(path);
4010 }
4011
4012 btrfs_free_path(path);
4013
4014 return ret;
4015}
4016
4017static noinline_for_stack int scrub_supers(struct scrub_ctx *sctx,
4018 struct btrfs_device *scrub_dev)
4019{
4020 int i;
4021 u64 bytenr;
4022 u64 gen;
4023 int ret;
4024 struct btrfs_fs_info *fs_info = sctx->fs_info;
4025
4026 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
4027 return -EIO;
4028
4029 /* Seed devices of a new filesystem has their own generation. */
4030 if (scrub_dev->fs_devices != fs_info->fs_devices)
4031 gen = scrub_dev->generation;
4032 else
4033 gen = fs_info->last_trans_committed;
4034
4035 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
4036 bytenr = btrfs_sb_offset(i);
4037 if (bytenr + BTRFS_SUPER_INFO_SIZE >
4038 scrub_dev->commit_total_bytes)
4039 break;
4040
4041 ret = scrub_pages(sctx, bytenr, BTRFS_SUPER_INFO_SIZE, bytenr,
4042 scrub_dev, BTRFS_EXTENT_FLAG_SUPER, gen, i,
4043 NULL, 1, bytenr);
4044 if (ret)
4045 return ret;
4046 }
4047 wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
4048
4049 return 0;
4050}
4051
4052/*
4053 * get a reference count on fs_info->scrub_workers. start worker if necessary
4054 */
4055static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info,
4056 int is_dev_replace)
4057{
4058 unsigned int flags = WQ_FREEZABLE | WQ_UNBOUND;
4059 int max_active = fs_info->thread_pool_size;
4060
4061 if (fs_info->scrub_workers_refcnt == 0) {
4062 fs_info->scrub_workers = btrfs_alloc_workqueue(fs_info, "scrub",
4063 flags, is_dev_replace ? 1 : max_active, 4);
4064 if (!fs_info->scrub_workers)
4065 goto fail_scrub_workers;
4066
4067 fs_info->scrub_wr_completion_workers =
4068 btrfs_alloc_workqueue(fs_info, "scrubwrc", flags,
4069 max_active, 2);
4070 if (!fs_info->scrub_wr_completion_workers)
4071 goto fail_scrub_wr_completion_workers;
4072
4073 fs_info->scrub_nocow_workers =
4074 btrfs_alloc_workqueue(fs_info, "scrubnc", flags, 1, 0);
4075 if (!fs_info->scrub_nocow_workers)
4076 goto fail_scrub_nocow_workers;
4077 fs_info->scrub_parity_workers =
4078 btrfs_alloc_workqueue(fs_info, "scrubparity", flags,
4079 max_active, 2);
4080 if (!fs_info->scrub_parity_workers)
4081 goto fail_scrub_parity_workers;
4082 }
4083 ++fs_info->scrub_workers_refcnt;
4084 return 0;
4085
4086fail_scrub_parity_workers:
4087 btrfs_destroy_workqueue(fs_info->scrub_nocow_workers);
4088fail_scrub_nocow_workers:
4089 btrfs_destroy_workqueue(fs_info->scrub_wr_completion_workers);
4090fail_scrub_wr_completion_workers:
4091 btrfs_destroy_workqueue(fs_info->scrub_workers);
4092fail_scrub_workers:
4093 return -ENOMEM;
4094}
4095
4096static noinline_for_stack void scrub_workers_put(struct btrfs_fs_info *fs_info)
4097{
4098 if (--fs_info->scrub_workers_refcnt == 0) {
4099 btrfs_destroy_workqueue(fs_info->scrub_workers);
4100 btrfs_destroy_workqueue(fs_info->scrub_wr_completion_workers);
4101 btrfs_destroy_workqueue(fs_info->scrub_nocow_workers);
4102 btrfs_destroy_workqueue(fs_info->scrub_parity_workers);
4103 }
4104 WARN_ON(fs_info->scrub_workers_refcnt < 0);
4105}
4106
4107int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
4108 u64 end, struct btrfs_scrub_progress *progress,
4109 int readonly, int is_dev_replace)
4110{
4111 struct scrub_ctx *sctx;
4112 int ret;
4113 struct btrfs_device *dev;
4114 struct rcu_string *name;
4115
4116 if (btrfs_fs_closing(fs_info))
4117 return -EINVAL;
4118
4119 if (fs_info->nodesize > BTRFS_STRIPE_LEN) {
4120 /*
4121 * in this case scrub is unable to calculate the checksum
4122 * the way scrub is implemented. Do not handle this
4123 * situation at all because it won't ever happen.
4124 */
4125 btrfs_err(fs_info,
4126 "scrub: size assumption nodesize <= BTRFS_STRIPE_LEN (%d <= %d) fails",
4127 fs_info->nodesize,
4128 BTRFS_STRIPE_LEN);
4129 return -EINVAL;
4130 }
4131
4132 if (fs_info->sectorsize != PAGE_SIZE) {
4133 /* not supported for data w/o checksums */
4134 btrfs_err_rl(fs_info,
4135 "scrub: size assumption sectorsize != PAGE_SIZE (%d != %lu) fails",
4136 fs_info->sectorsize, PAGE_SIZE);
4137 return -EINVAL;
4138 }
4139
4140 if (fs_info->nodesize >
4141 PAGE_SIZE * SCRUB_MAX_PAGES_PER_BLOCK ||
4142 fs_info->sectorsize > PAGE_SIZE * SCRUB_MAX_PAGES_PER_BLOCK) {
4143 /*
4144 * would exhaust the array bounds of pagev member in
4145 * struct scrub_block
4146 */
4147 btrfs_err(fs_info,
4148 "scrub: size assumption nodesize and sectorsize <= SCRUB_MAX_PAGES_PER_BLOCK (%d <= %d && %d <= %d) fails",
4149 fs_info->nodesize,
4150 SCRUB_MAX_PAGES_PER_BLOCK,
4151 fs_info->sectorsize,
4152 SCRUB_MAX_PAGES_PER_BLOCK);
4153 return -EINVAL;
4154 }
4155
4156
4157 mutex_lock(&fs_info->fs_devices->device_list_mutex);
4158 dev = btrfs_find_device(fs_info, devid, NULL, NULL);
4159 if (!dev || (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state) &&
4160 !is_dev_replace)) {
4161 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
4162 return -ENODEV;
4163 }
4164
4165 if (!is_dev_replace && !readonly &&
4166 !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state)) {
4167 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
4168 rcu_read_lock();
4169 name = rcu_dereference(dev->name);
4170 btrfs_err(fs_info, "scrub: device %s is not writable",
4171 name->str);
4172 rcu_read_unlock();
4173 return -EROFS;
4174 }
4175
4176 mutex_lock(&fs_info->scrub_lock);
4177 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &dev->dev_state) ||
4178 test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &dev->dev_state)) {
4179 mutex_unlock(&fs_info->scrub_lock);
4180 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
4181 return -EIO;
4182 }
4183
4184 btrfs_dev_replace_read_lock(&fs_info->dev_replace);
4185 if (dev->scrub_ctx ||
4186 (!is_dev_replace &&
4187 btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))) {
4188 btrfs_dev_replace_read_unlock(&fs_info->dev_replace);
4189 mutex_unlock(&fs_info->scrub_lock);
4190 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
4191 return -EINPROGRESS;
4192 }
4193 btrfs_dev_replace_read_unlock(&fs_info->dev_replace);
4194
4195 ret = scrub_workers_get(fs_info, is_dev_replace);
4196 if (ret) {
4197 mutex_unlock(&fs_info->scrub_lock);
4198 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
4199 return ret;
4200 }
4201
4202 sctx = scrub_setup_ctx(dev, is_dev_replace);
4203 if (IS_ERR(sctx)) {
4204 mutex_unlock(&fs_info->scrub_lock);
4205 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
4206 scrub_workers_put(fs_info);
4207 return PTR_ERR(sctx);
4208 }
4209 sctx->readonly = readonly;
4210 dev->scrub_ctx = sctx;
4211 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
4212
4213 /*
4214 * checking @scrub_pause_req here, we can avoid
4215 * race between committing transaction and scrubbing.
4216 */
4217 __scrub_blocked_if_needed(fs_info);
4218 atomic_inc(&fs_info->scrubs_running);
4219 mutex_unlock(&fs_info->scrub_lock);
4220
4221 if (!is_dev_replace) {
4222 /*
4223 * by holding device list mutex, we can
4224 * kick off writing super in log tree sync.
4225 */
4226 mutex_lock(&fs_info->fs_devices->device_list_mutex);
4227 ret = scrub_supers(sctx, dev);
4228 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
4229 }
4230
4231 if (!ret)
4232 ret = scrub_enumerate_chunks(sctx, dev, start, end,
4233 is_dev_replace);
4234
4235 wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
4236 atomic_dec(&fs_info->scrubs_running);
4237 wake_up(&fs_info->scrub_pause_wait);
4238
4239 wait_event(sctx->list_wait, atomic_read(&sctx->workers_pending) == 0);
4240
4241 if (progress)
4242 memcpy(progress, &sctx->stat, sizeof(*progress));
4243
4244 mutex_lock(&fs_info->scrub_lock);
4245 dev->scrub_ctx = NULL;
4246 scrub_workers_put(fs_info);
4247 mutex_unlock(&fs_info->scrub_lock);
4248
4249 scrub_put_ctx(sctx);
4250
4251 return ret;
4252}
4253
4254void btrfs_scrub_pause(struct btrfs_fs_info *fs_info)
4255{
4256 mutex_lock(&fs_info->scrub_lock);
4257 atomic_inc(&fs_info->scrub_pause_req);
4258 while (atomic_read(&fs_info->scrubs_paused) !=
4259 atomic_read(&fs_info->scrubs_running)) {
4260 mutex_unlock(&fs_info->scrub_lock);
4261 wait_event(fs_info->scrub_pause_wait,
4262 atomic_read(&fs_info->scrubs_paused) ==
4263 atomic_read(&fs_info->scrubs_running));
4264 mutex_lock(&fs_info->scrub_lock);
4265 }
4266 mutex_unlock(&fs_info->scrub_lock);
4267}
4268
4269void btrfs_scrub_continue(struct btrfs_fs_info *fs_info)
4270{
4271 atomic_dec(&fs_info->scrub_pause_req);
4272 wake_up(&fs_info->scrub_pause_wait);
4273}
4274
4275int btrfs_scrub_cancel(struct btrfs_fs_info *fs_info)
4276{
4277 mutex_lock(&fs_info->scrub_lock);
4278 if (!atomic_read(&fs_info->scrubs_running)) {
4279 mutex_unlock(&fs_info->scrub_lock);
4280 return -ENOTCONN;
4281 }
4282
4283 atomic_inc(&fs_info->scrub_cancel_req);
4284 while (atomic_read(&fs_info->scrubs_running)) {
4285 mutex_unlock(&fs_info->scrub_lock);
4286 wait_event(fs_info->scrub_pause_wait,
4287 atomic_read(&fs_info->scrubs_running) == 0);
4288 mutex_lock(&fs_info->scrub_lock);
4289 }
4290 atomic_dec(&fs_info->scrub_cancel_req);
4291 mutex_unlock(&fs_info->scrub_lock);
4292
4293 return 0;
4294}
4295
4296int btrfs_scrub_cancel_dev(struct btrfs_fs_info *fs_info,
4297 struct btrfs_device *dev)
4298{
4299 struct scrub_ctx *sctx;
4300
4301 mutex_lock(&fs_info->scrub_lock);
4302 sctx = dev->scrub_ctx;
4303 if (!sctx) {
4304 mutex_unlock(&fs_info->scrub_lock);
4305 return -ENOTCONN;
4306 }
4307 atomic_inc(&sctx->cancel_req);
4308 while (dev->scrub_ctx) {
4309 mutex_unlock(&fs_info->scrub_lock);
4310 wait_event(fs_info->scrub_pause_wait,
4311 dev->scrub_ctx == NULL);
4312 mutex_lock(&fs_info->scrub_lock);
4313 }
4314 mutex_unlock(&fs_info->scrub_lock);
4315
4316 return 0;
4317}
4318
4319int btrfs_scrub_progress(struct btrfs_fs_info *fs_info, u64 devid,
4320 struct btrfs_scrub_progress *progress)
4321{
4322 struct btrfs_device *dev;
4323 struct scrub_ctx *sctx = NULL;
4324
4325 mutex_lock(&fs_info->fs_devices->device_list_mutex);
4326 dev = btrfs_find_device(fs_info, devid, NULL, NULL);
4327 if (dev)
4328 sctx = dev->scrub_ctx;
4329 if (sctx)
4330 memcpy(progress, &sctx->stat, sizeof(*progress));
4331 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
4332
4333 return dev ? (sctx ? 0 : -ENOTCONN) : -ENODEV;
4334}
4335
4336static void scrub_remap_extent(struct btrfs_fs_info *fs_info,
4337 u64 extent_logical, u64 extent_len,
4338 u64 *extent_physical,
4339 struct btrfs_device **extent_dev,
4340 int *extent_mirror_num)
4341{
4342 u64 mapped_length;
4343 struct btrfs_bio *bbio = NULL;
4344 int ret;
4345
4346 mapped_length = extent_len;
4347 ret = btrfs_map_block(fs_info, BTRFS_MAP_READ, extent_logical,
4348 &mapped_length, &bbio, 0);
4349 if (ret || !bbio || mapped_length < extent_len ||
4350 !bbio->stripes[0].dev->bdev) {
4351 btrfs_put_bbio(bbio);
4352 return;
4353 }
4354
4355 *extent_physical = bbio->stripes[0].physical;
4356 *extent_mirror_num = bbio->mirror_num;
4357 *extent_dev = bbio->stripes[0].dev;
4358 btrfs_put_bbio(bbio);
4359}
4360
4361static int copy_nocow_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
4362 int mirror_num, u64 physical_for_dev_replace)
4363{
4364 struct scrub_copy_nocow_ctx *nocow_ctx;
4365 struct btrfs_fs_info *fs_info = sctx->fs_info;
4366
4367 nocow_ctx = kzalloc(sizeof(*nocow_ctx), GFP_NOFS);
4368 if (!nocow_ctx) {
4369 spin_lock(&sctx->stat_lock);
4370 sctx->stat.malloc_errors++;
4371 spin_unlock(&sctx->stat_lock);
4372 return -ENOMEM;
4373 }
4374
4375 scrub_pending_trans_workers_inc(sctx);
4376
4377 nocow_ctx->sctx = sctx;
4378 nocow_ctx->logical = logical;
4379 nocow_ctx->len = len;
4380 nocow_ctx->mirror_num = mirror_num;
4381 nocow_ctx->physical_for_dev_replace = physical_for_dev_replace;
4382 btrfs_init_work(&nocow_ctx->work, btrfs_scrubnc_helper,
4383 copy_nocow_pages_worker, NULL, NULL);
4384 INIT_LIST_HEAD(&nocow_ctx->inodes);
4385 btrfs_queue_work(fs_info->scrub_nocow_workers,
4386 &nocow_ctx->work);
4387
4388 return 0;
4389}
4390
4391static int record_inode_for_nocow(u64 inum, u64 offset, u64 root, void *ctx)
4392{
4393 struct scrub_copy_nocow_ctx *nocow_ctx = ctx;
4394 struct scrub_nocow_inode *nocow_inode;
4395
4396 nocow_inode = kzalloc(sizeof(*nocow_inode), GFP_NOFS);
4397 if (!nocow_inode)
4398 return -ENOMEM;
4399 nocow_inode->inum = inum;
4400 nocow_inode->offset = offset;
4401 nocow_inode->root = root;
4402 list_add_tail(&nocow_inode->list, &nocow_ctx->inodes);
4403 return 0;
4404}
4405
4406#define COPY_COMPLETE 1
4407
4408static void copy_nocow_pages_worker(struct btrfs_work *work)
4409{
4410 struct scrub_copy_nocow_ctx *nocow_ctx =
4411 container_of(work, struct scrub_copy_nocow_ctx, work);
4412 struct scrub_ctx *sctx = nocow_ctx->sctx;
4413 struct btrfs_fs_info *fs_info = sctx->fs_info;
4414 struct btrfs_root *root = fs_info->extent_root;
4415 u64 logical = nocow_ctx->logical;
4416 u64 len = nocow_ctx->len;
4417 int mirror_num = nocow_ctx->mirror_num;
4418 u64 physical_for_dev_replace = nocow_ctx->physical_for_dev_replace;
4419 int ret;
4420 struct btrfs_trans_handle *trans = NULL;
4421 struct btrfs_path *path;
4422 int not_written = 0;
4423
4424 path = btrfs_alloc_path();
4425 if (!path) {
4426 spin_lock(&sctx->stat_lock);
4427 sctx->stat.malloc_errors++;
4428 spin_unlock(&sctx->stat_lock);
4429 not_written = 1;
4430 goto out;
4431 }
4432
4433 trans = btrfs_join_transaction(root);
4434 if (IS_ERR(trans)) {
4435 not_written = 1;
4436 goto out;
4437 }
4438
4439 ret = iterate_inodes_from_logical(logical, fs_info, path,
4440 record_inode_for_nocow, nocow_ctx, false);
4441 if (ret != 0 && ret != -ENOENT) {
4442 btrfs_warn(fs_info,
4443 "iterate_inodes_from_logical() failed: log %llu, phys %llu, len %llu, mir %u, ret %d",
4444 logical, physical_for_dev_replace, len, mirror_num,
4445 ret);
4446 not_written = 1;
4447 goto out;
4448 }
4449
4450 btrfs_end_transaction(trans);
4451 trans = NULL;
4452 while (!list_empty(&nocow_ctx->inodes)) {
4453 struct scrub_nocow_inode *entry;
4454 entry = list_first_entry(&nocow_ctx->inodes,
4455 struct scrub_nocow_inode,
4456 list);
4457 list_del_init(&entry->list);
4458 ret = copy_nocow_pages_for_inode(entry->inum, entry->offset,
4459 entry->root, nocow_ctx);
4460 kfree(entry);
4461 if (ret == COPY_COMPLETE) {
4462 ret = 0;
4463 break;
4464 } else if (ret) {
4465 break;
4466 }
4467 }
4468out:
4469 while (!list_empty(&nocow_ctx->inodes)) {
4470 struct scrub_nocow_inode *entry;
4471 entry = list_first_entry(&nocow_ctx->inodes,
4472 struct scrub_nocow_inode,
4473 list);
4474 list_del_init(&entry->list);
4475 kfree(entry);
4476 }
4477 if (trans && !IS_ERR(trans))
4478 btrfs_end_transaction(trans);
4479 if (not_written)
4480 btrfs_dev_replace_stats_inc(&fs_info->dev_replace.
4481 num_uncorrectable_read_errors);
4482
4483 btrfs_free_path(path);
4484 kfree(nocow_ctx);
4485
4486 scrub_pending_trans_workers_dec(sctx);
4487}
4488
4489static int check_extent_to_block(struct btrfs_inode *inode, u64 start, u64 len,
4490 u64 logical)
4491{
4492 struct extent_state *cached_state = NULL;
4493 struct btrfs_ordered_extent *ordered;
4494 struct extent_io_tree *io_tree;
4495 struct extent_map *em;
4496 u64 lockstart = start, lockend = start + len - 1;
4497 int ret = 0;
4498
4499 io_tree = &inode->io_tree;
4500
4501 lock_extent_bits(io_tree, lockstart, lockend, &cached_state);
4502 ordered = btrfs_lookup_ordered_range(inode, lockstart, len);
4503 if (ordered) {
4504 btrfs_put_ordered_extent(ordered);
4505 ret = 1;
4506 goto out_unlock;
4507 }
4508
4509 em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
4510 if (IS_ERR(em)) {
4511 ret = PTR_ERR(em);
4512 goto out_unlock;
4513 }
4514
4515 /*
4516 * This extent does not actually cover the logical extent anymore,
4517 * move on to the next inode.
4518 */
4519 if (em->block_start > logical ||
4520 em->block_start + em->block_len < logical + len ||
4521 test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
4522 free_extent_map(em);
4523 ret = 1;
4524 goto out_unlock;
4525 }
4526 free_extent_map(em);
4527
4528out_unlock:
4529 unlock_extent_cached(io_tree, lockstart, lockend, &cached_state);
4530 return ret;
4531}
4532
4533static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root,
4534 struct scrub_copy_nocow_ctx *nocow_ctx)
4535{
4536 struct btrfs_fs_info *fs_info = nocow_ctx->sctx->fs_info;
4537 struct btrfs_key key;
4538 struct inode *inode;
4539 struct page *page;
4540 struct btrfs_root *local_root;
4541 struct extent_io_tree *io_tree;
4542 u64 physical_for_dev_replace;
4543 u64 nocow_ctx_logical;
4544 u64 len = nocow_ctx->len;
4545 unsigned long index;
4546 int srcu_index;
4547 int ret = 0;
4548 int err = 0;
4549
4550 key.objectid = root;
4551 key.type = BTRFS_ROOT_ITEM_KEY;
4552 key.offset = (u64)-1;
4553
4554 srcu_index = srcu_read_lock(&fs_info->subvol_srcu);
4555
4556 local_root = btrfs_read_fs_root_no_name(fs_info, &key);
4557 if (IS_ERR(local_root)) {
4558 srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
4559 return PTR_ERR(local_root);
4560 }
4561
4562 key.type = BTRFS_INODE_ITEM_KEY;
4563 key.objectid = inum;
4564 key.offset = 0;
4565 inode = btrfs_iget(fs_info->sb, &key, local_root, NULL);
4566 srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
4567 if (IS_ERR(inode))
4568 return PTR_ERR(inode);
4569
4570 /* Avoid truncate/dio/punch hole.. */
4571 inode_lock(inode);
4572 inode_dio_wait(inode);
4573
4574 physical_for_dev_replace = nocow_ctx->physical_for_dev_replace;
4575 io_tree = &BTRFS_I(inode)->io_tree;
4576 nocow_ctx_logical = nocow_ctx->logical;
4577
4578 ret = check_extent_to_block(BTRFS_I(inode), offset, len,
4579 nocow_ctx_logical);
4580 if (ret) {
4581 ret = ret > 0 ? 0 : ret;
4582 goto out;
4583 }
4584
4585 while (len >= PAGE_SIZE) {
4586 index = offset >> PAGE_SHIFT;
4587again:
4588 page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
4589 if (!page) {
4590 btrfs_err(fs_info, "find_or_create_page() failed");
4591 ret = -ENOMEM;
4592 goto out;
4593 }
4594
4595 if (PageUptodate(page)) {
4596 if (PageDirty(page))
4597 goto next_page;
4598 } else {
4599 ClearPageError(page);
4600 err = extent_read_full_page(io_tree, page,
4601 btrfs_get_extent,
4602 nocow_ctx->mirror_num);
4603 if (err) {
4604 ret = err;
4605 goto next_page;
4606 }
4607
4608 lock_page(page);
4609 /*
4610 * If the page has been remove from the page cache,
4611 * the data on it is meaningless, because it may be
4612 * old one, the new data may be written into the new
4613 * page in the page cache.
4614 */
4615 if (page->mapping != inode->i_mapping) {
4616 unlock_page(page);
4617 put_page(page);
4618 goto again;
4619 }
4620 if (!PageUptodate(page)) {
4621 ret = -EIO;
4622 goto next_page;
4623 }
4624 }
4625
4626 ret = check_extent_to_block(BTRFS_I(inode), offset, len,
4627 nocow_ctx_logical);
4628 if (ret) {
4629 ret = ret > 0 ? 0 : ret;
4630 goto next_page;
4631 }
4632
4633 err = write_page_nocow(nocow_ctx->sctx,
4634 physical_for_dev_replace, page);
4635 if (err)
4636 ret = err;
4637next_page:
4638 unlock_page(page);
4639 put_page(page);
4640
4641 if (ret)
4642 break;
4643
4644 offset += PAGE_SIZE;
4645 physical_for_dev_replace += PAGE_SIZE;
4646 nocow_ctx_logical += PAGE_SIZE;
4647 len -= PAGE_SIZE;
4648 }
4649 ret = COPY_COMPLETE;
4650out:
4651 inode_unlock(inode);
4652 iput(inode);
4653 return ret;
4654}
4655
4656static int write_page_nocow(struct scrub_ctx *sctx,
4657 u64 physical_for_dev_replace, struct page *page)
4658{
4659 struct bio *bio;
4660 struct btrfs_device *dev;
4661
4662 dev = sctx->wr_tgtdev;
4663 if (!dev)
4664 return -EIO;
4665 if (!dev->bdev) {
4666 btrfs_warn_rl(dev->fs_info,
4667 "scrub write_page_nocow(bdev == NULL) is unexpected");
4668 return -EIO;
4669 }
4670 bio = btrfs_io_bio_alloc(1);
4671 bio->bi_iter.bi_size = 0;
4672 bio->bi_iter.bi_sector = physical_for_dev_replace >> 9;
4673 bio_set_dev(bio, dev->bdev);
4674 bio->bi_opf = REQ_OP_WRITE | REQ_SYNC;
4675 /* bio_add_page won't fail on a freshly allocated bio */
4676 bio_add_page(bio, page, PAGE_SIZE, 0);
4677
4678 if (btrfsic_submit_bio_wait(bio)) {
4679 bio_put(bio);
4680 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
4681 return -EIO;
4682 }
4683
4684 bio_put(bio);
4685 return 0;
4686}
1/*
2 * Copyright (C) 2011 STRATO. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19#include <linux/blkdev.h>
20#include "ctree.h"
21#include "volumes.h"
22#include "disk-io.h"
23#include "ordered-data.h"
24
25/*
26 * This is only the first step towards a full-features scrub. It reads all
27 * extent and super block and verifies the checksums. In case a bad checksum
28 * is found or the extent cannot be read, good data will be written back if
29 * any can be found.
30 *
31 * Future enhancements:
32 * - To enhance the performance, better read-ahead strategies for the
33 * extent-tree can be employed.
34 * - In case an unrepairable extent is encountered, track which files are
35 * affected and report them
36 * - In case of a read error on files with nodatasum, map the file and read
37 * the extent to trigger a writeback of the good copy
38 * - track and record media errors, throw out bad devices
39 * - add a mode to also read unallocated space
40 * - make the prefetch cancellable
41 */
42
43struct scrub_bio;
44struct scrub_page;
45struct scrub_dev;
46static void scrub_bio_end_io(struct bio *bio, int err);
47static void scrub_checksum(struct btrfs_work *work);
48static int scrub_checksum_data(struct scrub_dev *sdev,
49 struct scrub_page *spag, void *buffer);
50static int scrub_checksum_tree_block(struct scrub_dev *sdev,
51 struct scrub_page *spag, u64 logical,
52 void *buffer);
53static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer);
54static int scrub_fixup_check(struct scrub_bio *sbio, int ix);
55static void scrub_fixup_end_io(struct bio *bio, int err);
56static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector,
57 struct page *page);
58static void scrub_fixup(struct scrub_bio *sbio, int ix);
59
60#define SCRUB_PAGES_PER_BIO 16 /* 64k per bio */
61#define SCRUB_BIOS_PER_DEV 16 /* 1 MB per device in flight */
62
63struct scrub_page {
64 u64 flags; /* extent flags */
65 u64 generation;
66 u64 mirror_num;
67 int have_csum;
68 u8 csum[BTRFS_CSUM_SIZE];
69};
70
71struct scrub_bio {
72 int index;
73 struct scrub_dev *sdev;
74 struct bio *bio;
75 int err;
76 u64 logical;
77 u64 physical;
78 struct scrub_page spag[SCRUB_PAGES_PER_BIO];
79 u64 count;
80 int next_free;
81 struct btrfs_work work;
82};
83
84struct scrub_dev {
85 struct scrub_bio *bios[SCRUB_BIOS_PER_DEV];
86 struct btrfs_device *dev;
87 int first_free;
88 int curr;
89 atomic_t in_flight;
90 spinlock_t list_lock;
91 wait_queue_head_t list_wait;
92 u16 csum_size;
93 struct list_head csum_list;
94 atomic_t cancel_req;
95 int readonly;
96 /*
97 * statistics
98 */
99 struct btrfs_scrub_progress stat;
100 spinlock_t stat_lock;
101};
102
103static void scrub_free_csums(struct scrub_dev *sdev)
104{
105 while (!list_empty(&sdev->csum_list)) {
106 struct btrfs_ordered_sum *sum;
107 sum = list_first_entry(&sdev->csum_list,
108 struct btrfs_ordered_sum, list);
109 list_del(&sum->list);
110 kfree(sum);
111 }
112}
113
114static void scrub_free_bio(struct bio *bio)
115{
116 int i;
117 struct page *last_page = NULL;
118
119 if (!bio)
120 return;
121
122 for (i = 0; i < bio->bi_vcnt; ++i) {
123 if (bio->bi_io_vec[i].bv_page == last_page)
124 continue;
125 last_page = bio->bi_io_vec[i].bv_page;
126 __free_page(last_page);
127 }
128 bio_put(bio);
129}
130
131static noinline_for_stack void scrub_free_dev(struct scrub_dev *sdev)
132{
133 int i;
134
135 if (!sdev)
136 return;
137
138 for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
139 struct scrub_bio *sbio = sdev->bios[i];
140
141 if (!sbio)
142 break;
143
144 scrub_free_bio(sbio->bio);
145 kfree(sbio);
146 }
147
148 scrub_free_csums(sdev);
149 kfree(sdev);
150}
151
152static noinline_for_stack
153struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev)
154{
155 struct scrub_dev *sdev;
156 int i;
157 struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
158
159 sdev = kzalloc(sizeof(*sdev), GFP_NOFS);
160 if (!sdev)
161 goto nomem;
162 sdev->dev = dev;
163 for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
164 struct scrub_bio *sbio;
165
166 sbio = kzalloc(sizeof(*sbio), GFP_NOFS);
167 if (!sbio)
168 goto nomem;
169 sdev->bios[i] = sbio;
170
171 sbio->index = i;
172 sbio->sdev = sdev;
173 sbio->count = 0;
174 sbio->work.func = scrub_checksum;
175
176 if (i != SCRUB_BIOS_PER_DEV-1)
177 sdev->bios[i]->next_free = i + 1;
178 else
179 sdev->bios[i]->next_free = -1;
180 }
181 sdev->first_free = 0;
182 sdev->curr = -1;
183 atomic_set(&sdev->in_flight, 0);
184 atomic_set(&sdev->cancel_req, 0);
185 sdev->csum_size = btrfs_super_csum_size(&fs_info->super_copy);
186 INIT_LIST_HEAD(&sdev->csum_list);
187
188 spin_lock_init(&sdev->list_lock);
189 spin_lock_init(&sdev->stat_lock);
190 init_waitqueue_head(&sdev->list_wait);
191 return sdev;
192
193nomem:
194 scrub_free_dev(sdev);
195 return ERR_PTR(-ENOMEM);
196}
197
198/*
199 * scrub_recheck_error gets called when either verification of the page
200 * failed or the bio failed to read, e.g. with EIO. In the latter case,
201 * recheck_error gets called for every page in the bio, even though only
202 * one may be bad
203 */
204static void scrub_recheck_error(struct scrub_bio *sbio, int ix)
205{
206 if (sbio->err) {
207 if (scrub_fixup_io(READ, sbio->sdev->dev->bdev,
208 (sbio->physical + ix * PAGE_SIZE) >> 9,
209 sbio->bio->bi_io_vec[ix].bv_page) == 0) {
210 if (scrub_fixup_check(sbio, ix) == 0)
211 return;
212 }
213 }
214
215 scrub_fixup(sbio, ix);
216}
217
218static int scrub_fixup_check(struct scrub_bio *sbio, int ix)
219{
220 int ret = 1;
221 struct page *page;
222 void *buffer;
223 u64 flags = sbio->spag[ix].flags;
224
225 page = sbio->bio->bi_io_vec[ix].bv_page;
226 buffer = kmap_atomic(page, KM_USER0);
227 if (flags & BTRFS_EXTENT_FLAG_DATA) {
228 ret = scrub_checksum_data(sbio->sdev,
229 sbio->spag + ix, buffer);
230 } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
231 ret = scrub_checksum_tree_block(sbio->sdev,
232 sbio->spag + ix,
233 sbio->logical + ix * PAGE_SIZE,
234 buffer);
235 } else {
236 WARN_ON(1);
237 }
238 kunmap_atomic(buffer, KM_USER0);
239
240 return ret;
241}
242
243static void scrub_fixup_end_io(struct bio *bio, int err)
244{
245 complete((struct completion *)bio->bi_private);
246}
247
248static void scrub_fixup(struct scrub_bio *sbio, int ix)
249{
250 struct scrub_dev *sdev = sbio->sdev;
251 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
252 struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
253 struct btrfs_multi_bio *multi = NULL;
254 u64 logical = sbio->logical + ix * PAGE_SIZE;
255 u64 length;
256 int i;
257 int ret;
258 DECLARE_COMPLETION_ONSTACK(complete);
259
260 if ((sbio->spag[ix].flags & BTRFS_EXTENT_FLAG_DATA) &&
261 (sbio->spag[ix].have_csum == 0)) {
262 /*
263 * nodatasum, don't try to fix anything
264 * FIXME: we can do better, open the inode and trigger a
265 * writeback
266 */
267 goto uncorrectable;
268 }
269
270 length = PAGE_SIZE;
271 ret = btrfs_map_block(map_tree, REQ_WRITE, logical, &length,
272 &multi, 0);
273 if (ret || !multi || length < PAGE_SIZE) {
274 printk(KERN_ERR
275 "scrub_fixup: btrfs_map_block failed us for %llu\n",
276 (unsigned long long)logical);
277 WARN_ON(1);
278 return;
279 }
280
281 if (multi->num_stripes == 1)
282 /* there aren't any replicas */
283 goto uncorrectable;
284
285 /*
286 * first find a good copy
287 */
288 for (i = 0; i < multi->num_stripes; ++i) {
289 if (i == sbio->spag[ix].mirror_num)
290 continue;
291
292 if (scrub_fixup_io(READ, multi->stripes[i].dev->bdev,
293 multi->stripes[i].physical >> 9,
294 sbio->bio->bi_io_vec[ix].bv_page)) {
295 /* I/O-error, this is not a good copy */
296 continue;
297 }
298
299 if (scrub_fixup_check(sbio, ix) == 0)
300 break;
301 }
302 if (i == multi->num_stripes)
303 goto uncorrectable;
304
305 if (!sdev->readonly) {
306 /*
307 * bi_io_vec[ix].bv_page now contains good data, write it back
308 */
309 if (scrub_fixup_io(WRITE, sdev->dev->bdev,
310 (sbio->physical + ix * PAGE_SIZE) >> 9,
311 sbio->bio->bi_io_vec[ix].bv_page)) {
312 /* I/O-error, writeback failed, give up */
313 goto uncorrectable;
314 }
315 }
316
317 kfree(multi);
318 spin_lock(&sdev->stat_lock);
319 ++sdev->stat.corrected_errors;
320 spin_unlock(&sdev->stat_lock);
321
322 if (printk_ratelimit())
323 printk(KERN_ERR "btrfs: fixed up at %llu\n",
324 (unsigned long long)logical);
325 return;
326
327uncorrectable:
328 kfree(multi);
329 spin_lock(&sdev->stat_lock);
330 ++sdev->stat.uncorrectable_errors;
331 spin_unlock(&sdev->stat_lock);
332
333 if (printk_ratelimit())
334 printk(KERN_ERR "btrfs: unable to fixup at %llu\n",
335 (unsigned long long)logical);
336}
337
338static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector,
339 struct page *page)
340{
341 struct bio *bio = NULL;
342 int ret;
343 DECLARE_COMPLETION_ONSTACK(complete);
344
345 bio = bio_alloc(GFP_NOFS, 1);
346 bio->bi_bdev = bdev;
347 bio->bi_sector = sector;
348 bio_add_page(bio, page, PAGE_SIZE, 0);
349 bio->bi_end_io = scrub_fixup_end_io;
350 bio->bi_private = &complete;
351 submit_bio(rw, bio);
352
353 /* this will also unplug the queue */
354 wait_for_completion(&complete);
355
356 ret = !test_bit(BIO_UPTODATE, &bio->bi_flags);
357 bio_put(bio);
358 return ret;
359}
360
361static void scrub_bio_end_io(struct bio *bio, int err)
362{
363 struct scrub_bio *sbio = bio->bi_private;
364 struct scrub_dev *sdev = sbio->sdev;
365 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
366
367 sbio->err = err;
368 sbio->bio = bio;
369
370 btrfs_queue_worker(&fs_info->scrub_workers, &sbio->work);
371}
372
373static void scrub_checksum(struct btrfs_work *work)
374{
375 struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
376 struct scrub_dev *sdev = sbio->sdev;
377 struct page *page;
378 void *buffer;
379 int i;
380 u64 flags;
381 u64 logical;
382 int ret;
383
384 if (sbio->err) {
385 for (i = 0; i < sbio->count; ++i)
386 scrub_recheck_error(sbio, i);
387
388 sbio->bio->bi_flags &= ~(BIO_POOL_MASK - 1);
389 sbio->bio->bi_flags |= 1 << BIO_UPTODATE;
390 sbio->bio->bi_phys_segments = 0;
391 sbio->bio->bi_idx = 0;
392
393 for (i = 0; i < sbio->count; i++) {
394 struct bio_vec *bi;
395 bi = &sbio->bio->bi_io_vec[i];
396 bi->bv_offset = 0;
397 bi->bv_len = PAGE_SIZE;
398 }
399
400 spin_lock(&sdev->stat_lock);
401 ++sdev->stat.read_errors;
402 spin_unlock(&sdev->stat_lock);
403 goto out;
404 }
405 for (i = 0; i < sbio->count; ++i) {
406 page = sbio->bio->bi_io_vec[i].bv_page;
407 buffer = kmap_atomic(page, KM_USER0);
408 flags = sbio->spag[i].flags;
409 logical = sbio->logical + i * PAGE_SIZE;
410 ret = 0;
411 if (flags & BTRFS_EXTENT_FLAG_DATA) {
412 ret = scrub_checksum_data(sdev, sbio->spag + i, buffer);
413 } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
414 ret = scrub_checksum_tree_block(sdev, sbio->spag + i,
415 logical, buffer);
416 } else if (flags & BTRFS_EXTENT_FLAG_SUPER) {
417 BUG_ON(i);
418 (void)scrub_checksum_super(sbio, buffer);
419 } else {
420 WARN_ON(1);
421 }
422 kunmap_atomic(buffer, KM_USER0);
423 if (ret)
424 scrub_recheck_error(sbio, i);
425 }
426
427out:
428 scrub_free_bio(sbio->bio);
429 sbio->bio = NULL;
430 spin_lock(&sdev->list_lock);
431 sbio->next_free = sdev->first_free;
432 sdev->first_free = sbio->index;
433 spin_unlock(&sdev->list_lock);
434 atomic_dec(&sdev->in_flight);
435 wake_up(&sdev->list_wait);
436}
437
438static int scrub_checksum_data(struct scrub_dev *sdev,
439 struct scrub_page *spag, void *buffer)
440{
441 u8 csum[BTRFS_CSUM_SIZE];
442 u32 crc = ~(u32)0;
443 int fail = 0;
444 struct btrfs_root *root = sdev->dev->dev_root;
445
446 if (!spag->have_csum)
447 return 0;
448
449 crc = btrfs_csum_data(root, buffer, crc, PAGE_SIZE);
450 btrfs_csum_final(crc, csum);
451 if (memcmp(csum, spag->csum, sdev->csum_size))
452 fail = 1;
453
454 spin_lock(&sdev->stat_lock);
455 ++sdev->stat.data_extents_scrubbed;
456 sdev->stat.data_bytes_scrubbed += PAGE_SIZE;
457 if (fail)
458 ++sdev->stat.csum_errors;
459 spin_unlock(&sdev->stat_lock);
460
461 return fail;
462}
463
464static int scrub_checksum_tree_block(struct scrub_dev *sdev,
465 struct scrub_page *spag, u64 logical,
466 void *buffer)
467{
468 struct btrfs_header *h;
469 struct btrfs_root *root = sdev->dev->dev_root;
470 struct btrfs_fs_info *fs_info = root->fs_info;
471 u8 csum[BTRFS_CSUM_SIZE];
472 u32 crc = ~(u32)0;
473 int fail = 0;
474 int crc_fail = 0;
475
476 /*
477 * we don't use the getter functions here, as we
478 * a) don't have an extent buffer and
479 * b) the page is already kmapped
480 */
481 h = (struct btrfs_header *)buffer;
482
483 if (logical != le64_to_cpu(h->bytenr))
484 ++fail;
485
486 if (spag->generation != le64_to_cpu(h->generation))
487 ++fail;
488
489 if (memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
490 ++fail;
491
492 if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
493 BTRFS_UUID_SIZE))
494 ++fail;
495
496 crc = btrfs_csum_data(root, buffer + BTRFS_CSUM_SIZE, crc,
497 PAGE_SIZE - BTRFS_CSUM_SIZE);
498 btrfs_csum_final(crc, csum);
499 if (memcmp(csum, h->csum, sdev->csum_size))
500 ++crc_fail;
501
502 spin_lock(&sdev->stat_lock);
503 ++sdev->stat.tree_extents_scrubbed;
504 sdev->stat.tree_bytes_scrubbed += PAGE_SIZE;
505 if (crc_fail)
506 ++sdev->stat.csum_errors;
507 if (fail)
508 ++sdev->stat.verify_errors;
509 spin_unlock(&sdev->stat_lock);
510
511 return fail || crc_fail;
512}
513
514static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer)
515{
516 struct btrfs_super_block *s;
517 u64 logical;
518 struct scrub_dev *sdev = sbio->sdev;
519 struct btrfs_root *root = sdev->dev->dev_root;
520 struct btrfs_fs_info *fs_info = root->fs_info;
521 u8 csum[BTRFS_CSUM_SIZE];
522 u32 crc = ~(u32)0;
523 int fail = 0;
524
525 s = (struct btrfs_super_block *)buffer;
526 logical = sbio->logical;
527
528 if (logical != le64_to_cpu(s->bytenr))
529 ++fail;
530
531 if (sbio->spag[0].generation != le64_to_cpu(s->generation))
532 ++fail;
533
534 if (memcmp(s->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
535 ++fail;
536
537 crc = btrfs_csum_data(root, buffer + BTRFS_CSUM_SIZE, crc,
538 PAGE_SIZE - BTRFS_CSUM_SIZE);
539 btrfs_csum_final(crc, csum);
540 if (memcmp(csum, s->csum, sbio->sdev->csum_size))
541 ++fail;
542
543 if (fail) {
544 /*
545 * if we find an error in a super block, we just report it.
546 * They will get written with the next transaction commit
547 * anyway
548 */
549 spin_lock(&sdev->stat_lock);
550 ++sdev->stat.super_errors;
551 spin_unlock(&sdev->stat_lock);
552 }
553
554 return fail;
555}
556
557static int scrub_submit(struct scrub_dev *sdev)
558{
559 struct scrub_bio *sbio;
560 struct bio *bio;
561 int i;
562
563 if (sdev->curr == -1)
564 return 0;
565
566 sbio = sdev->bios[sdev->curr];
567
568 bio = bio_alloc(GFP_NOFS, sbio->count);
569 if (!bio)
570 goto nomem;
571
572 bio->bi_private = sbio;
573 bio->bi_end_io = scrub_bio_end_io;
574 bio->bi_bdev = sdev->dev->bdev;
575 bio->bi_sector = sbio->physical >> 9;
576
577 for (i = 0; i < sbio->count; ++i) {
578 struct page *page;
579 int ret;
580
581 page = alloc_page(GFP_NOFS);
582 if (!page)
583 goto nomem;
584
585 ret = bio_add_page(bio, page, PAGE_SIZE, 0);
586 if (!ret) {
587 __free_page(page);
588 goto nomem;
589 }
590 }
591
592 sbio->err = 0;
593 sdev->curr = -1;
594 atomic_inc(&sdev->in_flight);
595
596 submit_bio(READ, bio);
597
598 return 0;
599
600nomem:
601 scrub_free_bio(bio);
602
603 return -ENOMEM;
604}
605
606static int scrub_page(struct scrub_dev *sdev, u64 logical, u64 len,
607 u64 physical, u64 flags, u64 gen, u64 mirror_num,
608 u8 *csum, int force)
609{
610 struct scrub_bio *sbio;
611
612again:
613 /*
614 * grab a fresh bio or wait for one to become available
615 */
616 while (sdev->curr == -1) {
617 spin_lock(&sdev->list_lock);
618 sdev->curr = sdev->first_free;
619 if (sdev->curr != -1) {
620 sdev->first_free = sdev->bios[sdev->curr]->next_free;
621 sdev->bios[sdev->curr]->next_free = -1;
622 sdev->bios[sdev->curr]->count = 0;
623 spin_unlock(&sdev->list_lock);
624 } else {
625 spin_unlock(&sdev->list_lock);
626 wait_event(sdev->list_wait, sdev->first_free != -1);
627 }
628 }
629 sbio = sdev->bios[sdev->curr];
630 if (sbio->count == 0) {
631 sbio->physical = physical;
632 sbio->logical = logical;
633 } else if (sbio->physical + sbio->count * PAGE_SIZE != physical ||
634 sbio->logical + sbio->count * PAGE_SIZE != logical) {
635 int ret;
636
637 ret = scrub_submit(sdev);
638 if (ret)
639 return ret;
640 goto again;
641 }
642 sbio->spag[sbio->count].flags = flags;
643 sbio->spag[sbio->count].generation = gen;
644 sbio->spag[sbio->count].have_csum = 0;
645 sbio->spag[sbio->count].mirror_num = mirror_num;
646 if (csum) {
647 sbio->spag[sbio->count].have_csum = 1;
648 memcpy(sbio->spag[sbio->count].csum, csum, sdev->csum_size);
649 }
650 ++sbio->count;
651 if (sbio->count == SCRUB_PAGES_PER_BIO || force) {
652 int ret;
653
654 ret = scrub_submit(sdev);
655 if (ret)
656 return ret;
657 }
658
659 return 0;
660}
661
662static int scrub_find_csum(struct scrub_dev *sdev, u64 logical, u64 len,
663 u8 *csum)
664{
665 struct btrfs_ordered_sum *sum = NULL;
666 int ret = 0;
667 unsigned long i;
668 unsigned long num_sectors;
669 u32 sectorsize = sdev->dev->dev_root->sectorsize;
670
671 while (!list_empty(&sdev->csum_list)) {
672 sum = list_first_entry(&sdev->csum_list,
673 struct btrfs_ordered_sum, list);
674 if (sum->bytenr > logical)
675 return 0;
676 if (sum->bytenr + sum->len > logical)
677 break;
678
679 ++sdev->stat.csum_discards;
680 list_del(&sum->list);
681 kfree(sum);
682 sum = NULL;
683 }
684 if (!sum)
685 return 0;
686
687 num_sectors = sum->len / sectorsize;
688 for (i = 0; i < num_sectors; ++i) {
689 if (sum->sums[i].bytenr == logical) {
690 memcpy(csum, &sum->sums[i].sum, sdev->csum_size);
691 ret = 1;
692 break;
693 }
694 }
695 if (ret && i == num_sectors - 1) {
696 list_del(&sum->list);
697 kfree(sum);
698 }
699 return ret;
700}
701
702/* scrub extent tries to collect up to 64 kB for each bio */
703static int scrub_extent(struct scrub_dev *sdev, u64 logical, u64 len,
704 u64 physical, u64 flags, u64 gen, u64 mirror_num)
705{
706 int ret;
707 u8 csum[BTRFS_CSUM_SIZE];
708
709 while (len) {
710 u64 l = min_t(u64, len, PAGE_SIZE);
711 int have_csum = 0;
712
713 if (flags & BTRFS_EXTENT_FLAG_DATA) {
714 /* push csums to sbio */
715 have_csum = scrub_find_csum(sdev, logical, l, csum);
716 if (have_csum == 0)
717 ++sdev->stat.no_csum;
718 }
719 ret = scrub_page(sdev, logical, l, physical, flags, gen,
720 mirror_num, have_csum ? csum : NULL, 0);
721 if (ret)
722 return ret;
723 len -= l;
724 logical += l;
725 physical += l;
726 }
727 return 0;
728}
729
730static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev,
731 struct map_lookup *map, int num, u64 base, u64 length)
732{
733 struct btrfs_path *path;
734 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
735 struct btrfs_root *root = fs_info->extent_root;
736 struct btrfs_root *csum_root = fs_info->csum_root;
737 struct btrfs_extent_item *extent;
738 struct blk_plug plug;
739 u64 flags;
740 int ret;
741 int slot;
742 int i;
743 u64 nstripes;
744 int start_stripe;
745 struct extent_buffer *l;
746 struct btrfs_key key;
747 u64 physical;
748 u64 logical;
749 u64 generation;
750 u64 mirror_num;
751
752 u64 increment = map->stripe_len;
753 u64 offset;
754
755 nstripes = length;
756 offset = 0;
757 do_div(nstripes, map->stripe_len);
758 if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
759 offset = map->stripe_len * num;
760 increment = map->stripe_len * map->num_stripes;
761 mirror_num = 0;
762 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
763 int factor = map->num_stripes / map->sub_stripes;
764 offset = map->stripe_len * (num / map->sub_stripes);
765 increment = map->stripe_len * factor;
766 mirror_num = num % map->sub_stripes;
767 } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
768 increment = map->stripe_len;
769 mirror_num = num % map->num_stripes;
770 } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
771 increment = map->stripe_len;
772 mirror_num = num % map->num_stripes;
773 } else {
774 increment = map->stripe_len;
775 mirror_num = 0;
776 }
777
778 path = btrfs_alloc_path();
779 if (!path)
780 return -ENOMEM;
781
782 path->reada = 2;
783 path->search_commit_root = 1;
784 path->skip_locking = 1;
785
786 /*
787 * find all extents for each stripe and just read them to get
788 * them into the page cache
789 * FIXME: we can do better. build a more intelligent prefetching
790 */
791 logical = base + offset;
792 physical = map->stripes[num].physical;
793 ret = 0;
794 for (i = 0; i < nstripes; ++i) {
795 key.objectid = logical;
796 key.type = BTRFS_EXTENT_ITEM_KEY;
797 key.offset = (u64)0;
798
799 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
800 if (ret < 0)
801 goto out_noplug;
802
803 /*
804 * we might miss half an extent here, but that doesn't matter,
805 * as it's only the prefetch
806 */
807 while (1) {
808 l = path->nodes[0];
809 slot = path->slots[0];
810 if (slot >= btrfs_header_nritems(l)) {
811 ret = btrfs_next_leaf(root, path);
812 if (ret == 0)
813 continue;
814 if (ret < 0)
815 goto out_noplug;
816
817 break;
818 }
819 btrfs_item_key_to_cpu(l, &key, slot);
820
821 if (key.objectid >= logical + map->stripe_len)
822 break;
823
824 path->slots[0]++;
825 }
826 btrfs_release_path(path);
827 logical += increment;
828 physical += map->stripe_len;
829 cond_resched();
830 }
831
832 /*
833 * collect all data csums for the stripe to avoid seeking during
834 * the scrub. This might currently (crc32) end up to be about 1MB
835 */
836 start_stripe = 0;
837 blk_start_plug(&plug);
838again:
839 logical = base + offset + start_stripe * increment;
840 for (i = start_stripe; i < nstripes; ++i) {
841 ret = btrfs_lookup_csums_range(csum_root, logical,
842 logical + map->stripe_len - 1,
843 &sdev->csum_list, 1);
844 if (ret)
845 goto out;
846
847 logical += increment;
848 cond_resched();
849 }
850 /*
851 * now find all extents for each stripe and scrub them
852 */
853 logical = base + offset + start_stripe * increment;
854 physical = map->stripes[num].physical + start_stripe * map->stripe_len;
855 ret = 0;
856 for (i = start_stripe; i < nstripes; ++i) {
857 /*
858 * canceled?
859 */
860 if (atomic_read(&fs_info->scrub_cancel_req) ||
861 atomic_read(&sdev->cancel_req)) {
862 ret = -ECANCELED;
863 goto out;
864 }
865 /*
866 * check to see if we have to pause
867 */
868 if (atomic_read(&fs_info->scrub_pause_req)) {
869 /* push queued extents */
870 scrub_submit(sdev);
871 wait_event(sdev->list_wait,
872 atomic_read(&sdev->in_flight) == 0);
873 atomic_inc(&fs_info->scrubs_paused);
874 wake_up(&fs_info->scrub_pause_wait);
875 mutex_lock(&fs_info->scrub_lock);
876 while (atomic_read(&fs_info->scrub_pause_req)) {
877 mutex_unlock(&fs_info->scrub_lock);
878 wait_event(fs_info->scrub_pause_wait,
879 atomic_read(&fs_info->scrub_pause_req) == 0);
880 mutex_lock(&fs_info->scrub_lock);
881 }
882 atomic_dec(&fs_info->scrubs_paused);
883 mutex_unlock(&fs_info->scrub_lock);
884 wake_up(&fs_info->scrub_pause_wait);
885 scrub_free_csums(sdev);
886 start_stripe = i;
887 goto again;
888 }
889
890 key.objectid = logical;
891 key.type = BTRFS_EXTENT_ITEM_KEY;
892 key.offset = (u64)0;
893
894 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
895 if (ret < 0)
896 goto out;
897 if (ret > 0) {
898 ret = btrfs_previous_item(root, path, 0,
899 BTRFS_EXTENT_ITEM_KEY);
900 if (ret < 0)
901 goto out;
902 if (ret > 0) {
903 /* there's no smaller item, so stick with the
904 * larger one */
905 btrfs_release_path(path);
906 ret = btrfs_search_slot(NULL, root, &key,
907 path, 0, 0);
908 if (ret < 0)
909 goto out;
910 }
911 }
912
913 while (1) {
914 l = path->nodes[0];
915 slot = path->slots[0];
916 if (slot >= btrfs_header_nritems(l)) {
917 ret = btrfs_next_leaf(root, path);
918 if (ret == 0)
919 continue;
920 if (ret < 0)
921 goto out;
922
923 break;
924 }
925 btrfs_item_key_to_cpu(l, &key, slot);
926
927 if (key.objectid + key.offset <= logical)
928 goto next;
929
930 if (key.objectid >= logical + map->stripe_len)
931 break;
932
933 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY)
934 goto next;
935
936 extent = btrfs_item_ptr(l, slot,
937 struct btrfs_extent_item);
938 flags = btrfs_extent_flags(l, extent);
939 generation = btrfs_extent_generation(l, extent);
940
941 if (key.objectid < logical &&
942 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) {
943 printk(KERN_ERR
944 "btrfs scrub: tree block %llu spanning "
945 "stripes, ignored. logical=%llu\n",
946 (unsigned long long)key.objectid,
947 (unsigned long long)logical);
948 goto next;
949 }
950
951 /*
952 * trim extent to this stripe
953 */
954 if (key.objectid < logical) {
955 key.offset -= logical - key.objectid;
956 key.objectid = logical;
957 }
958 if (key.objectid + key.offset >
959 logical + map->stripe_len) {
960 key.offset = logical + map->stripe_len -
961 key.objectid;
962 }
963
964 ret = scrub_extent(sdev, key.objectid, key.offset,
965 key.objectid - logical + physical,
966 flags, generation, mirror_num);
967 if (ret)
968 goto out;
969
970next:
971 path->slots[0]++;
972 }
973 btrfs_release_path(path);
974 logical += increment;
975 physical += map->stripe_len;
976 spin_lock(&sdev->stat_lock);
977 sdev->stat.last_physical = physical;
978 spin_unlock(&sdev->stat_lock);
979 }
980 /* push queued extents */
981 scrub_submit(sdev);
982
983out:
984 blk_finish_plug(&plug);
985out_noplug:
986 btrfs_free_path(path);
987 return ret < 0 ? ret : 0;
988}
989
990static noinline_for_stack int scrub_chunk(struct scrub_dev *sdev,
991 u64 chunk_tree, u64 chunk_objectid, u64 chunk_offset, u64 length)
992{
993 struct btrfs_mapping_tree *map_tree =
994 &sdev->dev->dev_root->fs_info->mapping_tree;
995 struct map_lookup *map;
996 struct extent_map *em;
997 int i;
998 int ret = -EINVAL;
999
1000 read_lock(&map_tree->map_tree.lock);
1001 em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
1002 read_unlock(&map_tree->map_tree.lock);
1003
1004 if (!em)
1005 return -EINVAL;
1006
1007 map = (struct map_lookup *)em->bdev;
1008 if (em->start != chunk_offset)
1009 goto out;
1010
1011 if (em->len < length)
1012 goto out;
1013
1014 for (i = 0; i < map->num_stripes; ++i) {
1015 if (map->stripes[i].dev == sdev->dev) {
1016 ret = scrub_stripe(sdev, map, i, chunk_offset, length);
1017 if (ret)
1018 goto out;
1019 }
1020 }
1021out:
1022 free_extent_map(em);
1023
1024 return ret;
1025}
1026
1027static noinline_for_stack
1028int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end)
1029{
1030 struct btrfs_dev_extent *dev_extent = NULL;
1031 struct btrfs_path *path;
1032 struct btrfs_root *root = sdev->dev->dev_root;
1033 struct btrfs_fs_info *fs_info = root->fs_info;
1034 u64 length;
1035 u64 chunk_tree;
1036 u64 chunk_objectid;
1037 u64 chunk_offset;
1038 int ret;
1039 int slot;
1040 struct extent_buffer *l;
1041 struct btrfs_key key;
1042 struct btrfs_key found_key;
1043 struct btrfs_block_group_cache *cache;
1044
1045 path = btrfs_alloc_path();
1046 if (!path)
1047 return -ENOMEM;
1048
1049 path->reada = 2;
1050 path->search_commit_root = 1;
1051 path->skip_locking = 1;
1052
1053 key.objectid = sdev->dev->devid;
1054 key.offset = 0ull;
1055 key.type = BTRFS_DEV_EXTENT_KEY;
1056
1057
1058 while (1) {
1059 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1060 if (ret < 0)
1061 break;
1062 if (ret > 0) {
1063 if (path->slots[0] >=
1064 btrfs_header_nritems(path->nodes[0])) {
1065 ret = btrfs_next_leaf(root, path);
1066 if (ret)
1067 break;
1068 }
1069 }
1070
1071 l = path->nodes[0];
1072 slot = path->slots[0];
1073
1074 btrfs_item_key_to_cpu(l, &found_key, slot);
1075
1076 if (found_key.objectid != sdev->dev->devid)
1077 break;
1078
1079 if (btrfs_key_type(&found_key) != BTRFS_DEV_EXTENT_KEY)
1080 break;
1081
1082 if (found_key.offset >= end)
1083 break;
1084
1085 if (found_key.offset < key.offset)
1086 break;
1087
1088 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1089 length = btrfs_dev_extent_length(l, dev_extent);
1090
1091 if (found_key.offset + length <= start) {
1092 key.offset = found_key.offset + length;
1093 btrfs_release_path(path);
1094 continue;
1095 }
1096
1097 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
1098 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
1099 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
1100
1101 /*
1102 * get a reference on the corresponding block group to prevent
1103 * the chunk from going away while we scrub it
1104 */
1105 cache = btrfs_lookup_block_group(fs_info, chunk_offset);
1106 if (!cache) {
1107 ret = -ENOENT;
1108 break;
1109 }
1110 ret = scrub_chunk(sdev, chunk_tree, chunk_objectid,
1111 chunk_offset, length);
1112 btrfs_put_block_group(cache);
1113 if (ret)
1114 break;
1115
1116 key.offset = found_key.offset + length;
1117 btrfs_release_path(path);
1118 }
1119
1120 btrfs_free_path(path);
1121
1122 /*
1123 * ret can still be 1 from search_slot or next_leaf,
1124 * that's not an error
1125 */
1126 return ret < 0 ? ret : 0;
1127}
1128
1129static noinline_for_stack int scrub_supers(struct scrub_dev *sdev)
1130{
1131 int i;
1132 u64 bytenr;
1133 u64 gen;
1134 int ret;
1135 struct btrfs_device *device = sdev->dev;
1136 struct btrfs_root *root = device->dev_root;
1137
1138 gen = root->fs_info->last_trans_committed;
1139
1140 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
1141 bytenr = btrfs_sb_offset(i);
1142 if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
1143 break;
1144
1145 ret = scrub_page(sdev, bytenr, PAGE_SIZE, bytenr,
1146 BTRFS_EXTENT_FLAG_SUPER, gen, i, NULL, 1);
1147 if (ret)
1148 return ret;
1149 }
1150 wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
1151
1152 return 0;
1153}
1154
1155/*
1156 * get a reference count on fs_info->scrub_workers. start worker if necessary
1157 */
1158static noinline_for_stack int scrub_workers_get(struct btrfs_root *root)
1159{
1160 struct btrfs_fs_info *fs_info = root->fs_info;
1161
1162 mutex_lock(&fs_info->scrub_lock);
1163 if (fs_info->scrub_workers_refcnt == 0) {
1164 btrfs_init_workers(&fs_info->scrub_workers, "scrub",
1165 fs_info->thread_pool_size, &fs_info->generic_worker);
1166 fs_info->scrub_workers.idle_thresh = 4;
1167 btrfs_start_workers(&fs_info->scrub_workers, 1);
1168 }
1169 ++fs_info->scrub_workers_refcnt;
1170 mutex_unlock(&fs_info->scrub_lock);
1171
1172 return 0;
1173}
1174
1175static noinline_for_stack void scrub_workers_put(struct btrfs_root *root)
1176{
1177 struct btrfs_fs_info *fs_info = root->fs_info;
1178
1179 mutex_lock(&fs_info->scrub_lock);
1180 if (--fs_info->scrub_workers_refcnt == 0)
1181 btrfs_stop_workers(&fs_info->scrub_workers);
1182 WARN_ON(fs_info->scrub_workers_refcnt < 0);
1183 mutex_unlock(&fs_info->scrub_lock);
1184}
1185
1186
1187int btrfs_scrub_dev(struct btrfs_root *root, u64 devid, u64 start, u64 end,
1188 struct btrfs_scrub_progress *progress, int readonly)
1189{
1190 struct scrub_dev *sdev;
1191 struct btrfs_fs_info *fs_info = root->fs_info;
1192 int ret;
1193 struct btrfs_device *dev;
1194
1195 if (btrfs_fs_closing(root->fs_info))
1196 return -EINVAL;
1197
1198 /*
1199 * check some assumptions
1200 */
1201 if (root->sectorsize != PAGE_SIZE ||
1202 root->sectorsize != root->leafsize ||
1203 root->sectorsize != root->nodesize) {
1204 printk(KERN_ERR "btrfs_scrub: size assumptions fail\n");
1205 return -EINVAL;
1206 }
1207
1208 ret = scrub_workers_get(root);
1209 if (ret)
1210 return ret;
1211
1212 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1213 dev = btrfs_find_device(root, devid, NULL, NULL);
1214 if (!dev || dev->missing) {
1215 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1216 scrub_workers_put(root);
1217 return -ENODEV;
1218 }
1219 mutex_lock(&fs_info->scrub_lock);
1220
1221 if (!dev->in_fs_metadata) {
1222 mutex_unlock(&fs_info->scrub_lock);
1223 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1224 scrub_workers_put(root);
1225 return -ENODEV;
1226 }
1227
1228 if (dev->scrub_device) {
1229 mutex_unlock(&fs_info->scrub_lock);
1230 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1231 scrub_workers_put(root);
1232 return -EINPROGRESS;
1233 }
1234 sdev = scrub_setup_dev(dev);
1235 if (IS_ERR(sdev)) {
1236 mutex_unlock(&fs_info->scrub_lock);
1237 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1238 scrub_workers_put(root);
1239 return PTR_ERR(sdev);
1240 }
1241 sdev->readonly = readonly;
1242 dev->scrub_device = sdev;
1243
1244 atomic_inc(&fs_info->scrubs_running);
1245 mutex_unlock(&fs_info->scrub_lock);
1246 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1247
1248 down_read(&fs_info->scrub_super_lock);
1249 ret = scrub_supers(sdev);
1250 up_read(&fs_info->scrub_super_lock);
1251
1252 if (!ret)
1253 ret = scrub_enumerate_chunks(sdev, start, end);
1254
1255 wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
1256
1257 atomic_dec(&fs_info->scrubs_running);
1258 wake_up(&fs_info->scrub_pause_wait);
1259
1260 if (progress)
1261 memcpy(progress, &sdev->stat, sizeof(*progress));
1262
1263 mutex_lock(&fs_info->scrub_lock);
1264 dev->scrub_device = NULL;
1265 mutex_unlock(&fs_info->scrub_lock);
1266
1267 scrub_free_dev(sdev);
1268 scrub_workers_put(root);
1269
1270 return ret;
1271}
1272
1273int btrfs_scrub_pause(struct btrfs_root *root)
1274{
1275 struct btrfs_fs_info *fs_info = root->fs_info;
1276
1277 mutex_lock(&fs_info->scrub_lock);
1278 atomic_inc(&fs_info->scrub_pause_req);
1279 while (atomic_read(&fs_info->scrubs_paused) !=
1280 atomic_read(&fs_info->scrubs_running)) {
1281 mutex_unlock(&fs_info->scrub_lock);
1282 wait_event(fs_info->scrub_pause_wait,
1283 atomic_read(&fs_info->scrubs_paused) ==
1284 atomic_read(&fs_info->scrubs_running));
1285 mutex_lock(&fs_info->scrub_lock);
1286 }
1287 mutex_unlock(&fs_info->scrub_lock);
1288
1289 return 0;
1290}
1291
1292int btrfs_scrub_continue(struct btrfs_root *root)
1293{
1294 struct btrfs_fs_info *fs_info = root->fs_info;
1295
1296 atomic_dec(&fs_info->scrub_pause_req);
1297 wake_up(&fs_info->scrub_pause_wait);
1298 return 0;
1299}
1300
1301int btrfs_scrub_pause_super(struct btrfs_root *root)
1302{
1303 down_write(&root->fs_info->scrub_super_lock);
1304 return 0;
1305}
1306
1307int btrfs_scrub_continue_super(struct btrfs_root *root)
1308{
1309 up_write(&root->fs_info->scrub_super_lock);
1310 return 0;
1311}
1312
1313int btrfs_scrub_cancel(struct btrfs_root *root)
1314{
1315 struct btrfs_fs_info *fs_info = root->fs_info;
1316
1317 mutex_lock(&fs_info->scrub_lock);
1318 if (!atomic_read(&fs_info->scrubs_running)) {
1319 mutex_unlock(&fs_info->scrub_lock);
1320 return -ENOTCONN;
1321 }
1322
1323 atomic_inc(&fs_info->scrub_cancel_req);
1324 while (atomic_read(&fs_info->scrubs_running)) {
1325 mutex_unlock(&fs_info->scrub_lock);
1326 wait_event(fs_info->scrub_pause_wait,
1327 atomic_read(&fs_info->scrubs_running) == 0);
1328 mutex_lock(&fs_info->scrub_lock);
1329 }
1330 atomic_dec(&fs_info->scrub_cancel_req);
1331 mutex_unlock(&fs_info->scrub_lock);
1332
1333 return 0;
1334}
1335
1336int btrfs_scrub_cancel_dev(struct btrfs_root *root, struct btrfs_device *dev)
1337{
1338 struct btrfs_fs_info *fs_info = root->fs_info;
1339 struct scrub_dev *sdev;
1340
1341 mutex_lock(&fs_info->scrub_lock);
1342 sdev = dev->scrub_device;
1343 if (!sdev) {
1344 mutex_unlock(&fs_info->scrub_lock);
1345 return -ENOTCONN;
1346 }
1347 atomic_inc(&sdev->cancel_req);
1348 while (dev->scrub_device) {
1349 mutex_unlock(&fs_info->scrub_lock);
1350 wait_event(fs_info->scrub_pause_wait,
1351 dev->scrub_device == NULL);
1352 mutex_lock(&fs_info->scrub_lock);
1353 }
1354 mutex_unlock(&fs_info->scrub_lock);
1355
1356 return 0;
1357}
1358int btrfs_scrub_cancel_devid(struct btrfs_root *root, u64 devid)
1359{
1360 struct btrfs_fs_info *fs_info = root->fs_info;
1361 struct btrfs_device *dev;
1362 int ret;
1363
1364 /*
1365 * we have to hold the device_list_mutex here so the device
1366 * does not go away in cancel_dev. FIXME: find a better solution
1367 */
1368 mutex_lock(&fs_info->fs_devices->device_list_mutex);
1369 dev = btrfs_find_device(root, devid, NULL, NULL);
1370 if (!dev) {
1371 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1372 return -ENODEV;
1373 }
1374 ret = btrfs_scrub_cancel_dev(root, dev);
1375 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1376
1377 return ret;
1378}
1379
1380int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
1381 struct btrfs_scrub_progress *progress)
1382{
1383 struct btrfs_device *dev;
1384 struct scrub_dev *sdev = NULL;
1385
1386 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1387 dev = btrfs_find_device(root, devid, NULL, NULL);
1388 if (dev)
1389 sdev = dev->scrub_device;
1390 if (sdev)
1391 memcpy(progress, &sdev->stat, sizeof(*progress));
1392 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1393
1394 return dev ? (sdev ? 0 : -ENOTCONN) : -ENODEV;
1395}