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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}
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 <linux/ratelimit.h>
21#include "ctree.h"
22#include "volumes.h"
23#include "disk-io.h"
24#include "ordered-data.h"
25#include "transaction.h"
26#include "backref.h"
27#include "extent_io.h"
28#include "check-integrity.h"
29#include "rcu-string.h"
30
31/*
32 * This is only the first step towards a full-features scrub. It reads all
33 * extent and super block and verifies the checksums. In case a bad checksum
34 * is found or the extent cannot be read, good data will be written back if
35 * any can be found.
36 *
37 * Future enhancements:
38 * - In case an unrepairable extent is encountered, track which files are
39 * affected and report them
40 * - track and record media errors, throw out bad devices
41 * - add a mode to also read unallocated space
42 */
43
44struct scrub_block;
45struct scrub_dev;
46
47#define SCRUB_PAGES_PER_BIO 16 /* 64k per bio */
48#define SCRUB_BIOS_PER_DEV 16 /* 1 MB per device in flight */
49#define SCRUB_MAX_PAGES_PER_BLOCK 16 /* 64k per node/leaf/sector */
50
51struct scrub_page {
52 struct scrub_block *sblock;
53 struct page *page;
54 struct btrfs_device *dev;
55 u64 flags; /* extent flags */
56 u64 generation;
57 u64 logical;
58 u64 physical;
59 struct {
60 unsigned int mirror_num:8;
61 unsigned int have_csum:1;
62 unsigned int io_error:1;
63 };
64 u8 csum[BTRFS_CSUM_SIZE];
65};
66
67struct scrub_bio {
68 int index;
69 struct scrub_dev *sdev;
70 struct bio *bio;
71 int err;
72 u64 logical;
73 u64 physical;
74 struct scrub_page *pagev[SCRUB_PAGES_PER_BIO];
75 int page_count;
76 int next_free;
77 struct btrfs_work work;
78};
79
80struct scrub_block {
81 struct scrub_page pagev[SCRUB_MAX_PAGES_PER_BLOCK];
82 int page_count;
83 atomic_t outstanding_pages;
84 atomic_t ref_count; /* free mem on transition to zero */
85 struct scrub_dev *sdev;
86 struct {
87 unsigned int header_error:1;
88 unsigned int checksum_error:1;
89 unsigned int no_io_error_seen:1;
90 unsigned int generation_error:1; /* also sets header_error */
91 };
92};
93
94struct scrub_dev {
95 struct scrub_bio *bios[SCRUB_BIOS_PER_DEV];
96 struct btrfs_device *dev;
97 int first_free;
98 int curr;
99 atomic_t in_flight;
100 atomic_t fixup_cnt;
101 spinlock_t list_lock;
102 wait_queue_head_t list_wait;
103 u16 csum_size;
104 struct list_head csum_list;
105 atomic_t cancel_req;
106 int readonly;
107 int pages_per_bio; /* <= SCRUB_PAGES_PER_BIO */
108 u32 sectorsize;
109 u32 nodesize;
110 u32 leafsize;
111 /*
112 * statistics
113 */
114 struct btrfs_scrub_progress stat;
115 spinlock_t stat_lock;
116};
117
118struct scrub_fixup_nodatasum {
119 struct scrub_dev *sdev;
120 u64 logical;
121 struct btrfs_root *root;
122 struct btrfs_work work;
123 int mirror_num;
124};
125
126struct scrub_warning {
127 struct btrfs_path *path;
128 u64 extent_item_size;
129 char *scratch_buf;
130 char *msg_buf;
131 const char *errstr;
132 sector_t sector;
133 u64 logical;
134 struct btrfs_device *dev;
135 int msg_bufsize;
136 int scratch_bufsize;
137};
138
139
140static int scrub_handle_errored_block(struct scrub_block *sblock_to_check);
141static int scrub_setup_recheck_block(struct scrub_dev *sdev,
142 struct btrfs_mapping_tree *map_tree,
143 u64 length, u64 logical,
144 struct scrub_block *sblock);
145static int scrub_recheck_block(struct btrfs_fs_info *fs_info,
146 struct scrub_block *sblock, int is_metadata,
147 int have_csum, u8 *csum, u64 generation,
148 u16 csum_size);
149static void scrub_recheck_block_checksum(struct btrfs_fs_info *fs_info,
150 struct scrub_block *sblock,
151 int is_metadata, int have_csum,
152 const u8 *csum, u64 generation,
153 u16 csum_size);
154static void scrub_complete_bio_end_io(struct bio *bio, int err);
155static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
156 struct scrub_block *sblock_good,
157 int force_write);
158static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
159 struct scrub_block *sblock_good,
160 int page_num, int force_write);
161static int scrub_checksum_data(struct scrub_block *sblock);
162static int scrub_checksum_tree_block(struct scrub_block *sblock);
163static int scrub_checksum_super(struct scrub_block *sblock);
164static void scrub_block_get(struct scrub_block *sblock);
165static void scrub_block_put(struct scrub_block *sblock);
166static int scrub_add_page_to_bio(struct scrub_dev *sdev,
167 struct scrub_page *spage);
168static int scrub_pages(struct scrub_dev *sdev, u64 logical, u64 len,
169 u64 physical, u64 flags, u64 gen, int mirror_num,
170 u8 *csum, int force);
171static void scrub_bio_end_io(struct bio *bio, int err);
172static void scrub_bio_end_io_worker(struct btrfs_work *work);
173static void scrub_block_complete(struct scrub_block *sblock);
174
175
176static void scrub_free_csums(struct scrub_dev *sdev)
177{
178 while (!list_empty(&sdev->csum_list)) {
179 struct btrfs_ordered_sum *sum;
180 sum = list_first_entry(&sdev->csum_list,
181 struct btrfs_ordered_sum, list);
182 list_del(&sum->list);
183 kfree(sum);
184 }
185}
186
187static noinline_for_stack void scrub_free_dev(struct scrub_dev *sdev)
188{
189 int i;
190
191 if (!sdev)
192 return;
193
194 /* this can happen when scrub is cancelled */
195 if (sdev->curr != -1) {
196 struct scrub_bio *sbio = sdev->bios[sdev->curr];
197
198 for (i = 0; i < sbio->page_count; i++) {
199 BUG_ON(!sbio->pagev[i]);
200 BUG_ON(!sbio->pagev[i]->page);
201 scrub_block_put(sbio->pagev[i]->sblock);
202 }
203 bio_put(sbio->bio);
204 }
205
206 for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
207 struct scrub_bio *sbio = sdev->bios[i];
208
209 if (!sbio)
210 break;
211 kfree(sbio);
212 }
213
214 scrub_free_csums(sdev);
215 kfree(sdev);
216}
217
218static noinline_for_stack
219struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev)
220{
221 struct scrub_dev *sdev;
222 int i;
223 struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
224 int pages_per_bio;
225
226 pages_per_bio = min_t(int, SCRUB_PAGES_PER_BIO,
227 bio_get_nr_vecs(dev->bdev));
228 sdev = kzalloc(sizeof(*sdev), GFP_NOFS);
229 if (!sdev)
230 goto nomem;
231 sdev->dev = dev;
232 sdev->pages_per_bio = pages_per_bio;
233 sdev->curr = -1;
234 for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
235 struct scrub_bio *sbio;
236
237 sbio = kzalloc(sizeof(*sbio), GFP_NOFS);
238 if (!sbio)
239 goto nomem;
240 sdev->bios[i] = sbio;
241
242 sbio->index = i;
243 sbio->sdev = sdev;
244 sbio->page_count = 0;
245 sbio->work.func = scrub_bio_end_io_worker;
246
247 if (i != SCRUB_BIOS_PER_DEV-1)
248 sdev->bios[i]->next_free = i + 1;
249 else
250 sdev->bios[i]->next_free = -1;
251 }
252 sdev->first_free = 0;
253 sdev->nodesize = dev->dev_root->nodesize;
254 sdev->leafsize = dev->dev_root->leafsize;
255 sdev->sectorsize = dev->dev_root->sectorsize;
256 atomic_set(&sdev->in_flight, 0);
257 atomic_set(&sdev->fixup_cnt, 0);
258 atomic_set(&sdev->cancel_req, 0);
259 sdev->csum_size = btrfs_super_csum_size(fs_info->super_copy);
260 INIT_LIST_HEAD(&sdev->csum_list);
261
262 spin_lock_init(&sdev->list_lock);
263 spin_lock_init(&sdev->stat_lock);
264 init_waitqueue_head(&sdev->list_wait);
265 return sdev;
266
267nomem:
268 scrub_free_dev(sdev);
269 return ERR_PTR(-ENOMEM);
270}
271
272static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root, void *ctx)
273{
274 u64 isize;
275 u32 nlink;
276 int ret;
277 int i;
278 struct extent_buffer *eb;
279 struct btrfs_inode_item *inode_item;
280 struct scrub_warning *swarn = ctx;
281 struct btrfs_fs_info *fs_info = swarn->dev->dev_root->fs_info;
282 struct inode_fs_paths *ipath = NULL;
283 struct btrfs_root *local_root;
284 struct btrfs_key root_key;
285
286 root_key.objectid = root;
287 root_key.type = BTRFS_ROOT_ITEM_KEY;
288 root_key.offset = (u64)-1;
289 local_root = btrfs_read_fs_root_no_name(fs_info, &root_key);
290 if (IS_ERR(local_root)) {
291 ret = PTR_ERR(local_root);
292 goto err;
293 }
294
295 ret = inode_item_info(inum, 0, local_root, swarn->path);
296 if (ret) {
297 btrfs_release_path(swarn->path);
298 goto err;
299 }
300
301 eb = swarn->path->nodes[0];
302 inode_item = btrfs_item_ptr(eb, swarn->path->slots[0],
303 struct btrfs_inode_item);
304 isize = btrfs_inode_size(eb, inode_item);
305 nlink = btrfs_inode_nlink(eb, inode_item);
306 btrfs_release_path(swarn->path);
307
308 ipath = init_ipath(4096, local_root, swarn->path);
309 if (IS_ERR(ipath)) {
310 ret = PTR_ERR(ipath);
311 ipath = NULL;
312 goto err;
313 }
314 ret = paths_from_inode(inum, ipath);
315
316 if (ret < 0)
317 goto err;
318
319 /*
320 * we deliberately ignore the bit ipath might have been too small to
321 * hold all of the paths here
322 */
323 for (i = 0; i < ipath->fspath->elem_cnt; ++i)
324 printk_in_rcu(KERN_WARNING "btrfs: %s at logical %llu on dev "
325 "%s, sector %llu, root %llu, inode %llu, offset %llu, "
326 "length %llu, links %u (path: %s)\n", swarn->errstr,
327 swarn->logical, rcu_str_deref(swarn->dev->name),
328 (unsigned long long)swarn->sector, root, inum, offset,
329 min(isize - offset, (u64)PAGE_SIZE), nlink,
330 (char *)(unsigned long)ipath->fspath->val[i]);
331
332 free_ipath(ipath);
333 return 0;
334
335err:
336 printk_in_rcu(KERN_WARNING "btrfs: %s at logical %llu on dev "
337 "%s, sector %llu, root %llu, inode %llu, offset %llu: path "
338 "resolving failed with ret=%d\n", swarn->errstr,
339 swarn->logical, rcu_str_deref(swarn->dev->name),
340 (unsigned long long)swarn->sector, root, inum, offset, ret);
341
342 free_ipath(ipath);
343 return 0;
344}
345
346static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
347{
348 struct btrfs_device *dev = sblock->sdev->dev;
349 struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
350 struct btrfs_path *path;
351 struct btrfs_key found_key;
352 struct extent_buffer *eb;
353 struct btrfs_extent_item *ei;
354 struct scrub_warning swarn;
355 u32 item_size;
356 int ret;
357 u64 ref_root;
358 u8 ref_level;
359 unsigned long ptr = 0;
360 const int bufsize = 4096;
361 u64 extent_item_pos;
362
363 path = btrfs_alloc_path();
364
365 swarn.scratch_buf = kmalloc(bufsize, GFP_NOFS);
366 swarn.msg_buf = kmalloc(bufsize, GFP_NOFS);
367 BUG_ON(sblock->page_count < 1);
368 swarn.sector = (sblock->pagev[0].physical) >> 9;
369 swarn.logical = sblock->pagev[0].logical;
370 swarn.errstr = errstr;
371 swarn.dev = dev;
372 swarn.msg_bufsize = bufsize;
373 swarn.scratch_bufsize = bufsize;
374
375 if (!path || !swarn.scratch_buf || !swarn.msg_buf)
376 goto out;
377
378 ret = extent_from_logical(fs_info, swarn.logical, path, &found_key);
379 if (ret < 0)
380 goto out;
381
382 extent_item_pos = swarn.logical - found_key.objectid;
383 swarn.extent_item_size = found_key.offset;
384
385 eb = path->nodes[0];
386 ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
387 item_size = btrfs_item_size_nr(eb, path->slots[0]);
388 btrfs_release_path(path);
389
390 if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
391 do {
392 ret = tree_backref_for_extent(&ptr, eb, ei, item_size,
393 &ref_root, &ref_level);
394 printk_in_rcu(KERN_WARNING
395 "btrfs: %s at logical %llu on dev %s, "
396 "sector %llu: metadata %s (level %d) in tree "
397 "%llu\n", errstr, swarn.logical,
398 rcu_str_deref(dev->name),
399 (unsigned long long)swarn.sector,
400 ref_level ? "node" : "leaf",
401 ret < 0 ? -1 : ref_level,
402 ret < 0 ? -1 : ref_root);
403 } while (ret != 1);
404 } else {
405 swarn.path = path;
406 iterate_extent_inodes(fs_info, found_key.objectid,
407 extent_item_pos, 1,
408 scrub_print_warning_inode, &swarn);
409 }
410
411out:
412 btrfs_free_path(path);
413 kfree(swarn.scratch_buf);
414 kfree(swarn.msg_buf);
415}
416
417static int scrub_fixup_readpage(u64 inum, u64 offset, u64 root, void *ctx)
418{
419 struct page *page = NULL;
420 unsigned long index;
421 struct scrub_fixup_nodatasum *fixup = ctx;
422 int ret;
423 int corrected = 0;
424 struct btrfs_key key;
425 struct inode *inode = NULL;
426 u64 end = offset + PAGE_SIZE - 1;
427 struct btrfs_root *local_root;
428
429 key.objectid = root;
430 key.type = BTRFS_ROOT_ITEM_KEY;
431 key.offset = (u64)-1;
432 local_root = btrfs_read_fs_root_no_name(fixup->root->fs_info, &key);
433 if (IS_ERR(local_root))
434 return PTR_ERR(local_root);
435
436 key.type = BTRFS_INODE_ITEM_KEY;
437 key.objectid = inum;
438 key.offset = 0;
439 inode = btrfs_iget(fixup->root->fs_info->sb, &key, local_root, NULL);
440 if (IS_ERR(inode))
441 return PTR_ERR(inode);
442
443 index = offset >> PAGE_CACHE_SHIFT;
444
445 page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
446 if (!page) {
447 ret = -ENOMEM;
448 goto out;
449 }
450
451 if (PageUptodate(page)) {
452 struct btrfs_mapping_tree *map_tree;
453 if (PageDirty(page)) {
454 /*
455 * we need to write the data to the defect sector. the
456 * data that was in that sector is not in memory,
457 * because the page was modified. we must not write the
458 * modified page to that sector.
459 *
460 * TODO: what could be done here: wait for the delalloc
461 * runner to write out that page (might involve
462 * COW) and see whether the sector is still
463 * referenced afterwards.
464 *
465 * For the meantime, we'll treat this error
466 * incorrectable, although there is a chance that a
467 * later scrub will find the bad sector again and that
468 * there's no dirty page in memory, then.
469 */
470 ret = -EIO;
471 goto out;
472 }
473 map_tree = &BTRFS_I(inode)->root->fs_info->mapping_tree;
474 ret = repair_io_failure(map_tree, offset, PAGE_SIZE,
475 fixup->logical, page,
476 fixup->mirror_num);
477 unlock_page(page);
478 corrected = !ret;
479 } else {
480 /*
481 * we need to get good data first. the general readpage path
482 * will call repair_io_failure for us, we just have to make
483 * sure we read the bad mirror.
484 */
485 ret = set_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
486 EXTENT_DAMAGED, GFP_NOFS);
487 if (ret) {
488 /* set_extent_bits should give proper error */
489 WARN_ON(ret > 0);
490 if (ret > 0)
491 ret = -EFAULT;
492 goto out;
493 }
494
495 ret = extent_read_full_page(&BTRFS_I(inode)->io_tree, page,
496 btrfs_get_extent,
497 fixup->mirror_num);
498 wait_on_page_locked(page);
499
500 corrected = !test_range_bit(&BTRFS_I(inode)->io_tree, offset,
501 end, EXTENT_DAMAGED, 0, NULL);
502 if (!corrected)
503 clear_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
504 EXTENT_DAMAGED, GFP_NOFS);
505 }
506
507out:
508 if (page)
509 put_page(page);
510 if (inode)
511 iput(inode);
512
513 if (ret < 0)
514 return ret;
515
516 if (ret == 0 && corrected) {
517 /*
518 * we only need to call readpage for one of the inodes belonging
519 * to this extent. so make iterate_extent_inodes stop
520 */
521 return 1;
522 }
523
524 return -EIO;
525}
526
527static void scrub_fixup_nodatasum(struct btrfs_work *work)
528{
529 int ret;
530 struct scrub_fixup_nodatasum *fixup;
531 struct scrub_dev *sdev;
532 struct btrfs_trans_handle *trans = NULL;
533 struct btrfs_fs_info *fs_info;
534 struct btrfs_path *path;
535 int uncorrectable = 0;
536
537 fixup = container_of(work, struct scrub_fixup_nodatasum, work);
538 sdev = fixup->sdev;
539 fs_info = fixup->root->fs_info;
540
541 path = btrfs_alloc_path();
542 if (!path) {
543 spin_lock(&sdev->stat_lock);
544 ++sdev->stat.malloc_errors;
545 spin_unlock(&sdev->stat_lock);
546 uncorrectable = 1;
547 goto out;
548 }
549
550 trans = btrfs_join_transaction(fixup->root);
551 if (IS_ERR(trans)) {
552 uncorrectable = 1;
553 goto out;
554 }
555
556 /*
557 * the idea is to trigger a regular read through the standard path. we
558 * read a page from the (failed) logical address by specifying the
559 * corresponding copynum of the failed sector. thus, that readpage is
560 * expected to fail.
561 * that is the point where on-the-fly error correction will kick in
562 * (once it's finished) and rewrite the failed sector if a good copy
563 * can be found.
564 */
565 ret = iterate_inodes_from_logical(fixup->logical, fixup->root->fs_info,
566 path, scrub_fixup_readpage,
567 fixup);
568 if (ret < 0) {
569 uncorrectable = 1;
570 goto out;
571 }
572 WARN_ON(ret != 1);
573
574 spin_lock(&sdev->stat_lock);
575 ++sdev->stat.corrected_errors;
576 spin_unlock(&sdev->stat_lock);
577
578out:
579 if (trans && !IS_ERR(trans))
580 btrfs_end_transaction(trans, fixup->root);
581 if (uncorrectable) {
582 spin_lock(&sdev->stat_lock);
583 ++sdev->stat.uncorrectable_errors;
584 spin_unlock(&sdev->stat_lock);
585
586 printk_ratelimited_in_rcu(KERN_ERR
587 "btrfs: unable to fixup (nodatasum) error at logical %llu on dev %s\n",
588 (unsigned long long)fixup->logical,
589 rcu_str_deref(sdev->dev->name));
590 }
591
592 btrfs_free_path(path);
593 kfree(fixup);
594
595 /* see caller why we're pretending to be paused in the scrub counters */
596 mutex_lock(&fs_info->scrub_lock);
597 atomic_dec(&fs_info->scrubs_running);
598 atomic_dec(&fs_info->scrubs_paused);
599 mutex_unlock(&fs_info->scrub_lock);
600 atomic_dec(&sdev->fixup_cnt);
601 wake_up(&fs_info->scrub_pause_wait);
602 wake_up(&sdev->list_wait);
603}
604
605/*
606 * scrub_handle_errored_block gets called when either verification of the
607 * pages failed or the bio failed to read, e.g. with EIO. In the latter
608 * case, this function handles all pages in the bio, even though only one
609 * may be bad.
610 * The goal of this function is to repair the errored block by using the
611 * contents of one of the mirrors.
612 */
613static int scrub_handle_errored_block(struct scrub_block *sblock_to_check)
614{
615 struct scrub_dev *sdev = sblock_to_check->sdev;
616 struct btrfs_fs_info *fs_info;
617 u64 length;
618 u64 logical;
619 u64 generation;
620 unsigned int failed_mirror_index;
621 unsigned int is_metadata;
622 unsigned int have_csum;
623 u8 *csum;
624 struct scrub_block *sblocks_for_recheck; /* holds one for each mirror */
625 struct scrub_block *sblock_bad;
626 int ret;
627 int mirror_index;
628 int page_num;
629 int success;
630 static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
631 DEFAULT_RATELIMIT_BURST);
632
633 BUG_ON(sblock_to_check->page_count < 1);
634 fs_info = sdev->dev->dev_root->fs_info;
635 length = sblock_to_check->page_count * PAGE_SIZE;
636 logical = sblock_to_check->pagev[0].logical;
637 generation = sblock_to_check->pagev[0].generation;
638 BUG_ON(sblock_to_check->pagev[0].mirror_num < 1);
639 failed_mirror_index = sblock_to_check->pagev[0].mirror_num - 1;
640 is_metadata = !(sblock_to_check->pagev[0].flags &
641 BTRFS_EXTENT_FLAG_DATA);
642 have_csum = sblock_to_check->pagev[0].have_csum;
643 csum = sblock_to_check->pagev[0].csum;
644
645 /*
646 * read all mirrors one after the other. This includes to
647 * re-read the extent or metadata block that failed (that was
648 * the cause that this fixup code is called) another time,
649 * page by page this time in order to know which pages
650 * caused I/O errors and which ones are good (for all mirrors).
651 * It is the goal to handle the situation when more than one
652 * mirror contains I/O errors, but the errors do not
653 * overlap, i.e. the data can be repaired by selecting the
654 * pages from those mirrors without I/O error on the
655 * particular pages. One example (with blocks >= 2 * PAGE_SIZE)
656 * would be that mirror #1 has an I/O error on the first page,
657 * the second page is good, and mirror #2 has an I/O error on
658 * the second page, but the first page is good.
659 * Then the first page of the first mirror can be repaired by
660 * taking the first page of the second mirror, and the
661 * second page of the second mirror can be repaired by
662 * copying the contents of the 2nd page of the 1st mirror.
663 * One more note: if the pages of one mirror contain I/O
664 * errors, the checksum cannot be verified. In order to get
665 * the best data for repairing, the first attempt is to find
666 * a mirror without I/O errors and with a validated checksum.
667 * Only if this is not possible, the pages are picked from
668 * mirrors with I/O errors without considering the checksum.
669 * If the latter is the case, at the end, the checksum of the
670 * repaired area is verified in order to correctly maintain
671 * the statistics.
672 */
673
674 sblocks_for_recheck = kzalloc(BTRFS_MAX_MIRRORS *
675 sizeof(*sblocks_for_recheck),
676 GFP_NOFS);
677 if (!sblocks_for_recheck) {
678 spin_lock(&sdev->stat_lock);
679 sdev->stat.malloc_errors++;
680 sdev->stat.read_errors++;
681 sdev->stat.uncorrectable_errors++;
682 spin_unlock(&sdev->stat_lock);
683 btrfs_dev_stat_inc_and_print(sdev->dev,
684 BTRFS_DEV_STAT_READ_ERRS);
685 goto out;
686 }
687
688 /* setup the context, map the logical blocks and alloc the pages */
689 ret = scrub_setup_recheck_block(sdev, &fs_info->mapping_tree, length,
690 logical, sblocks_for_recheck);
691 if (ret) {
692 spin_lock(&sdev->stat_lock);
693 sdev->stat.read_errors++;
694 sdev->stat.uncorrectable_errors++;
695 spin_unlock(&sdev->stat_lock);
696 btrfs_dev_stat_inc_and_print(sdev->dev,
697 BTRFS_DEV_STAT_READ_ERRS);
698 goto out;
699 }
700 BUG_ON(failed_mirror_index >= BTRFS_MAX_MIRRORS);
701 sblock_bad = sblocks_for_recheck + failed_mirror_index;
702
703 /* build and submit the bios for the failed mirror, check checksums */
704 ret = scrub_recheck_block(fs_info, sblock_bad, is_metadata, have_csum,
705 csum, generation, sdev->csum_size);
706 if (ret) {
707 spin_lock(&sdev->stat_lock);
708 sdev->stat.read_errors++;
709 sdev->stat.uncorrectable_errors++;
710 spin_unlock(&sdev->stat_lock);
711 btrfs_dev_stat_inc_and_print(sdev->dev,
712 BTRFS_DEV_STAT_READ_ERRS);
713 goto out;
714 }
715
716 if (!sblock_bad->header_error && !sblock_bad->checksum_error &&
717 sblock_bad->no_io_error_seen) {
718 /*
719 * the error disappeared after reading page by page, or
720 * the area was part of a huge bio and other parts of the
721 * bio caused I/O errors, or the block layer merged several
722 * read requests into one and the error is caused by a
723 * different bio (usually one of the two latter cases is
724 * the cause)
725 */
726 spin_lock(&sdev->stat_lock);
727 sdev->stat.unverified_errors++;
728 spin_unlock(&sdev->stat_lock);
729
730 goto out;
731 }
732
733 if (!sblock_bad->no_io_error_seen) {
734 spin_lock(&sdev->stat_lock);
735 sdev->stat.read_errors++;
736 spin_unlock(&sdev->stat_lock);
737 if (__ratelimit(&_rs))
738 scrub_print_warning("i/o error", sblock_to_check);
739 btrfs_dev_stat_inc_and_print(sdev->dev,
740 BTRFS_DEV_STAT_READ_ERRS);
741 } else if (sblock_bad->checksum_error) {
742 spin_lock(&sdev->stat_lock);
743 sdev->stat.csum_errors++;
744 spin_unlock(&sdev->stat_lock);
745 if (__ratelimit(&_rs))
746 scrub_print_warning("checksum error", sblock_to_check);
747 btrfs_dev_stat_inc_and_print(sdev->dev,
748 BTRFS_DEV_STAT_CORRUPTION_ERRS);
749 } else if (sblock_bad->header_error) {
750 spin_lock(&sdev->stat_lock);
751 sdev->stat.verify_errors++;
752 spin_unlock(&sdev->stat_lock);
753 if (__ratelimit(&_rs))
754 scrub_print_warning("checksum/header error",
755 sblock_to_check);
756 if (sblock_bad->generation_error)
757 btrfs_dev_stat_inc_and_print(sdev->dev,
758 BTRFS_DEV_STAT_GENERATION_ERRS);
759 else
760 btrfs_dev_stat_inc_and_print(sdev->dev,
761 BTRFS_DEV_STAT_CORRUPTION_ERRS);
762 }
763
764 if (sdev->readonly)
765 goto did_not_correct_error;
766
767 if (!is_metadata && !have_csum) {
768 struct scrub_fixup_nodatasum *fixup_nodatasum;
769
770 /*
771 * !is_metadata and !have_csum, this means that the data
772 * might not be COW'ed, that it might be modified
773 * concurrently. The general strategy to work on the
774 * commit root does not help in the case when COW is not
775 * used.
776 */
777 fixup_nodatasum = kzalloc(sizeof(*fixup_nodatasum), GFP_NOFS);
778 if (!fixup_nodatasum)
779 goto did_not_correct_error;
780 fixup_nodatasum->sdev = sdev;
781 fixup_nodatasum->logical = logical;
782 fixup_nodatasum->root = fs_info->extent_root;
783 fixup_nodatasum->mirror_num = failed_mirror_index + 1;
784 /*
785 * increment scrubs_running to prevent cancel requests from
786 * completing as long as a fixup worker is running. we must also
787 * increment scrubs_paused to prevent deadlocking on pause
788 * requests used for transactions commits (as the worker uses a
789 * transaction context). it is safe to regard the fixup worker
790 * as paused for all matters practical. effectively, we only
791 * avoid cancellation requests from completing.
792 */
793 mutex_lock(&fs_info->scrub_lock);
794 atomic_inc(&fs_info->scrubs_running);
795 atomic_inc(&fs_info->scrubs_paused);
796 mutex_unlock(&fs_info->scrub_lock);
797 atomic_inc(&sdev->fixup_cnt);
798 fixup_nodatasum->work.func = scrub_fixup_nodatasum;
799 btrfs_queue_worker(&fs_info->scrub_workers,
800 &fixup_nodatasum->work);
801 goto out;
802 }
803
804 /*
805 * now build and submit the bios for the other mirrors, check
806 * checksums
807 */
808 for (mirror_index = 0;
809 mirror_index < BTRFS_MAX_MIRRORS &&
810 sblocks_for_recheck[mirror_index].page_count > 0;
811 mirror_index++) {
812 if (mirror_index == failed_mirror_index)
813 continue;
814
815 /* build and submit the bios, check checksums */
816 ret = scrub_recheck_block(fs_info,
817 sblocks_for_recheck + mirror_index,
818 is_metadata, have_csum, csum,
819 generation, sdev->csum_size);
820 if (ret)
821 goto did_not_correct_error;
822 }
823
824 /*
825 * first try to pick the mirror which is completely without I/O
826 * errors and also does not have a checksum error.
827 * If one is found, and if a checksum is present, the full block
828 * that is known to contain an error is rewritten. Afterwards
829 * the block is known to be corrected.
830 * If a mirror is found which is completely correct, and no
831 * checksum is present, only those pages are rewritten that had
832 * an I/O error in the block to be repaired, since it cannot be
833 * determined, which copy of the other pages is better (and it
834 * could happen otherwise that a correct page would be
835 * overwritten by a bad one).
836 */
837 for (mirror_index = 0;
838 mirror_index < BTRFS_MAX_MIRRORS &&
839 sblocks_for_recheck[mirror_index].page_count > 0;
840 mirror_index++) {
841 struct scrub_block *sblock_other = sblocks_for_recheck +
842 mirror_index;
843
844 if (!sblock_other->header_error &&
845 !sblock_other->checksum_error &&
846 sblock_other->no_io_error_seen) {
847 int force_write = is_metadata || have_csum;
848
849 ret = scrub_repair_block_from_good_copy(sblock_bad,
850 sblock_other,
851 force_write);
852 if (0 == ret)
853 goto corrected_error;
854 }
855 }
856
857 /*
858 * in case of I/O errors in the area that is supposed to be
859 * repaired, continue by picking good copies of those pages.
860 * Select the good pages from mirrors to rewrite bad pages from
861 * the area to fix. Afterwards verify the checksum of the block
862 * that is supposed to be repaired. This verification step is
863 * only done for the purpose of statistic counting and for the
864 * final scrub report, whether errors remain.
865 * A perfect algorithm could make use of the checksum and try
866 * all possible combinations of pages from the different mirrors
867 * until the checksum verification succeeds. For example, when
868 * the 2nd page of mirror #1 faces I/O errors, and the 2nd page
869 * of mirror #2 is readable but the final checksum test fails,
870 * then the 2nd page of mirror #3 could be tried, whether now
871 * the final checksum succeedes. But this would be a rare
872 * exception and is therefore not implemented. At least it is
873 * avoided that the good copy is overwritten.
874 * A more useful improvement would be to pick the sectors
875 * without I/O error based on sector sizes (512 bytes on legacy
876 * disks) instead of on PAGE_SIZE. Then maybe 512 byte of one
877 * mirror could be repaired by taking 512 byte of a different
878 * mirror, even if other 512 byte sectors in the same PAGE_SIZE
879 * area are unreadable.
880 */
881
882 /* can only fix I/O errors from here on */
883 if (sblock_bad->no_io_error_seen)
884 goto did_not_correct_error;
885
886 success = 1;
887 for (page_num = 0; page_num < sblock_bad->page_count; page_num++) {
888 struct scrub_page *page_bad = sblock_bad->pagev + page_num;
889
890 if (!page_bad->io_error)
891 continue;
892
893 for (mirror_index = 0;
894 mirror_index < BTRFS_MAX_MIRRORS &&
895 sblocks_for_recheck[mirror_index].page_count > 0;
896 mirror_index++) {
897 struct scrub_block *sblock_other = sblocks_for_recheck +
898 mirror_index;
899 struct scrub_page *page_other = sblock_other->pagev +
900 page_num;
901
902 if (!page_other->io_error) {
903 ret = scrub_repair_page_from_good_copy(
904 sblock_bad, sblock_other, page_num, 0);
905 if (0 == ret) {
906 page_bad->io_error = 0;
907 break; /* succeeded for this page */
908 }
909 }
910 }
911
912 if (page_bad->io_error) {
913 /* did not find a mirror to copy the page from */
914 success = 0;
915 }
916 }
917
918 if (success) {
919 if (is_metadata || have_csum) {
920 /*
921 * need to verify the checksum now that all
922 * sectors on disk are repaired (the write
923 * request for data to be repaired is on its way).
924 * Just be lazy and use scrub_recheck_block()
925 * which re-reads the data before the checksum
926 * is verified, but most likely the data comes out
927 * of the page cache.
928 */
929 ret = scrub_recheck_block(fs_info, sblock_bad,
930 is_metadata, have_csum, csum,
931 generation, sdev->csum_size);
932 if (!ret && !sblock_bad->header_error &&
933 !sblock_bad->checksum_error &&
934 sblock_bad->no_io_error_seen)
935 goto corrected_error;
936 else
937 goto did_not_correct_error;
938 } else {
939corrected_error:
940 spin_lock(&sdev->stat_lock);
941 sdev->stat.corrected_errors++;
942 spin_unlock(&sdev->stat_lock);
943 printk_ratelimited_in_rcu(KERN_ERR
944 "btrfs: fixed up error at logical %llu on dev %s\n",
945 (unsigned long long)logical,
946 rcu_str_deref(sdev->dev->name));
947 }
948 } else {
949did_not_correct_error:
950 spin_lock(&sdev->stat_lock);
951 sdev->stat.uncorrectable_errors++;
952 spin_unlock(&sdev->stat_lock);
953 printk_ratelimited_in_rcu(KERN_ERR
954 "btrfs: unable to fixup (regular) error at logical %llu on dev %s\n",
955 (unsigned long long)logical,
956 rcu_str_deref(sdev->dev->name));
957 }
958
959out:
960 if (sblocks_for_recheck) {
961 for (mirror_index = 0; mirror_index < BTRFS_MAX_MIRRORS;
962 mirror_index++) {
963 struct scrub_block *sblock = sblocks_for_recheck +
964 mirror_index;
965 int page_index;
966
967 for (page_index = 0; page_index < SCRUB_PAGES_PER_BIO;
968 page_index++)
969 if (sblock->pagev[page_index].page)
970 __free_page(
971 sblock->pagev[page_index].page);
972 }
973 kfree(sblocks_for_recheck);
974 }
975
976 return 0;
977}
978
979static int scrub_setup_recheck_block(struct scrub_dev *sdev,
980 struct btrfs_mapping_tree *map_tree,
981 u64 length, u64 logical,
982 struct scrub_block *sblocks_for_recheck)
983{
984 int page_index;
985 int mirror_index;
986 int ret;
987
988 /*
989 * note: the three members sdev, ref_count and outstanding_pages
990 * are not used (and not set) in the blocks that are used for
991 * the recheck procedure
992 */
993
994 page_index = 0;
995 while (length > 0) {
996 u64 sublen = min_t(u64, length, PAGE_SIZE);
997 u64 mapped_length = sublen;
998 struct btrfs_bio *bbio = NULL;
999
1000 /*
1001 * with a length of PAGE_SIZE, each returned stripe
1002 * represents one mirror
1003 */
1004 ret = btrfs_map_block(map_tree, WRITE, logical, &mapped_length,
1005 &bbio, 0);
1006 if (ret || !bbio || mapped_length < sublen) {
1007 kfree(bbio);
1008 return -EIO;
1009 }
1010
1011 BUG_ON(page_index >= SCRUB_PAGES_PER_BIO);
1012 for (mirror_index = 0; mirror_index < (int)bbio->num_stripes;
1013 mirror_index++) {
1014 struct scrub_block *sblock;
1015 struct scrub_page *page;
1016
1017 if (mirror_index >= BTRFS_MAX_MIRRORS)
1018 continue;
1019
1020 sblock = sblocks_for_recheck + mirror_index;
1021 page = sblock->pagev + page_index;
1022 page->logical = logical;
1023 page->physical = bbio->stripes[mirror_index].physical;
1024 /* for missing devices, dev->bdev is NULL */
1025 page->dev = bbio->stripes[mirror_index].dev;
1026 page->mirror_num = mirror_index + 1;
1027 page->page = alloc_page(GFP_NOFS);
1028 if (!page->page) {
1029 spin_lock(&sdev->stat_lock);
1030 sdev->stat.malloc_errors++;
1031 spin_unlock(&sdev->stat_lock);
1032 return -ENOMEM;
1033 }
1034 sblock->page_count++;
1035 }
1036 kfree(bbio);
1037 length -= sublen;
1038 logical += sublen;
1039 page_index++;
1040 }
1041
1042 return 0;
1043}
1044
1045/*
1046 * this function will check the on disk data for checksum errors, header
1047 * errors and read I/O errors. If any I/O errors happen, the exact pages
1048 * which are errored are marked as being bad. The goal is to enable scrub
1049 * to take those pages that are not errored from all the mirrors so that
1050 * the pages that are errored in the just handled mirror can be repaired.
1051 */
1052static int scrub_recheck_block(struct btrfs_fs_info *fs_info,
1053 struct scrub_block *sblock, int is_metadata,
1054 int have_csum, u8 *csum, u64 generation,
1055 u16 csum_size)
1056{
1057 int page_num;
1058
1059 sblock->no_io_error_seen = 1;
1060 sblock->header_error = 0;
1061 sblock->checksum_error = 0;
1062
1063 for (page_num = 0; page_num < sblock->page_count; page_num++) {
1064 struct bio *bio;
1065 int ret;
1066 struct scrub_page *page = sblock->pagev + page_num;
1067 DECLARE_COMPLETION_ONSTACK(complete);
1068
1069 if (page->dev->bdev == NULL) {
1070 page->io_error = 1;
1071 sblock->no_io_error_seen = 0;
1072 continue;
1073 }
1074
1075 BUG_ON(!page->page);
1076 bio = bio_alloc(GFP_NOFS, 1);
1077 if (!bio)
1078 return -EIO;
1079 bio->bi_bdev = page->dev->bdev;
1080 bio->bi_sector = page->physical >> 9;
1081 bio->bi_end_io = scrub_complete_bio_end_io;
1082 bio->bi_private = &complete;
1083
1084 ret = bio_add_page(bio, page->page, PAGE_SIZE, 0);
1085 if (PAGE_SIZE != ret) {
1086 bio_put(bio);
1087 return -EIO;
1088 }
1089 btrfsic_submit_bio(READ, bio);
1090
1091 /* this will also unplug the queue */
1092 wait_for_completion(&complete);
1093
1094 page->io_error = !test_bit(BIO_UPTODATE, &bio->bi_flags);
1095 if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
1096 sblock->no_io_error_seen = 0;
1097 bio_put(bio);
1098 }
1099
1100 if (sblock->no_io_error_seen)
1101 scrub_recheck_block_checksum(fs_info, sblock, is_metadata,
1102 have_csum, csum, generation,
1103 csum_size);
1104
1105 return 0;
1106}
1107
1108static void scrub_recheck_block_checksum(struct btrfs_fs_info *fs_info,
1109 struct scrub_block *sblock,
1110 int is_metadata, int have_csum,
1111 const u8 *csum, u64 generation,
1112 u16 csum_size)
1113{
1114 int page_num;
1115 u8 calculated_csum[BTRFS_CSUM_SIZE];
1116 u32 crc = ~(u32)0;
1117 struct btrfs_root *root = fs_info->extent_root;
1118 void *mapped_buffer;
1119
1120 BUG_ON(!sblock->pagev[0].page);
1121 if (is_metadata) {
1122 struct btrfs_header *h;
1123
1124 mapped_buffer = kmap_atomic(sblock->pagev[0].page);
1125 h = (struct btrfs_header *)mapped_buffer;
1126
1127 if (sblock->pagev[0].logical != le64_to_cpu(h->bytenr) ||
1128 memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE) ||
1129 memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
1130 BTRFS_UUID_SIZE)) {
1131 sblock->header_error = 1;
1132 } else if (generation != le64_to_cpu(h->generation)) {
1133 sblock->header_error = 1;
1134 sblock->generation_error = 1;
1135 }
1136 csum = h->csum;
1137 } else {
1138 if (!have_csum)
1139 return;
1140
1141 mapped_buffer = kmap_atomic(sblock->pagev[0].page);
1142 }
1143
1144 for (page_num = 0;;) {
1145 if (page_num == 0 && is_metadata)
1146 crc = btrfs_csum_data(root,
1147 ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE,
1148 crc, PAGE_SIZE - BTRFS_CSUM_SIZE);
1149 else
1150 crc = btrfs_csum_data(root, mapped_buffer, crc,
1151 PAGE_SIZE);
1152
1153 kunmap_atomic(mapped_buffer);
1154 page_num++;
1155 if (page_num >= sblock->page_count)
1156 break;
1157 BUG_ON(!sblock->pagev[page_num].page);
1158
1159 mapped_buffer = kmap_atomic(sblock->pagev[page_num].page);
1160 }
1161
1162 btrfs_csum_final(crc, calculated_csum);
1163 if (memcmp(calculated_csum, csum, csum_size))
1164 sblock->checksum_error = 1;
1165}
1166
1167static void scrub_complete_bio_end_io(struct bio *bio, int err)
1168{
1169 complete((struct completion *)bio->bi_private);
1170}
1171
1172static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
1173 struct scrub_block *sblock_good,
1174 int force_write)
1175{
1176 int page_num;
1177 int ret = 0;
1178
1179 for (page_num = 0; page_num < sblock_bad->page_count; page_num++) {
1180 int ret_sub;
1181
1182 ret_sub = scrub_repair_page_from_good_copy(sblock_bad,
1183 sblock_good,
1184 page_num,
1185 force_write);
1186 if (ret_sub)
1187 ret = ret_sub;
1188 }
1189
1190 return ret;
1191}
1192
1193static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
1194 struct scrub_block *sblock_good,
1195 int page_num, int force_write)
1196{
1197 struct scrub_page *page_bad = sblock_bad->pagev + page_num;
1198 struct scrub_page *page_good = sblock_good->pagev + page_num;
1199
1200 BUG_ON(sblock_bad->pagev[page_num].page == NULL);
1201 BUG_ON(sblock_good->pagev[page_num].page == NULL);
1202 if (force_write || sblock_bad->header_error ||
1203 sblock_bad->checksum_error || page_bad->io_error) {
1204 struct bio *bio;
1205 int ret;
1206 DECLARE_COMPLETION_ONSTACK(complete);
1207
1208 bio = bio_alloc(GFP_NOFS, 1);
1209 if (!bio)
1210 return -EIO;
1211 bio->bi_bdev = page_bad->dev->bdev;
1212 bio->bi_sector = page_bad->physical >> 9;
1213 bio->bi_end_io = scrub_complete_bio_end_io;
1214 bio->bi_private = &complete;
1215
1216 ret = bio_add_page(bio, page_good->page, PAGE_SIZE, 0);
1217 if (PAGE_SIZE != ret) {
1218 bio_put(bio);
1219 return -EIO;
1220 }
1221 btrfsic_submit_bio(WRITE, bio);
1222
1223 /* this will also unplug the queue */
1224 wait_for_completion(&complete);
1225 if (!bio_flagged(bio, BIO_UPTODATE)) {
1226 btrfs_dev_stat_inc_and_print(page_bad->dev,
1227 BTRFS_DEV_STAT_WRITE_ERRS);
1228 bio_put(bio);
1229 return -EIO;
1230 }
1231 bio_put(bio);
1232 }
1233
1234 return 0;
1235}
1236
1237static void scrub_checksum(struct scrub_block *sblock)
1238{
1239 u64 flags;
1240 int ret;
1241
1242 BUG_ON(sblock->page_count < 1);
1243 flags = sblock->pagev[0].flags;
1244 ret = 0;
1245 if (flags & BTRFS_EXTENT_FLAG_DATA)
1246 ret = scrub_checksum_data(sblock);
1247 else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1248 ret = scrub_checksum_tree_block(sblock);
1249 else if (flags & BTRFS_EXTENT_FLAG_SUPER)
1250 (void)scrub_checksum_super(sblock);
1251 else
1252 WARN_ON(1);
1253 if (ret)
1254 scrub_handle_errored_block(sblock);
1255}
1256
1257static int scrub_checksum_data(struct scrub_block *sblock)
1258{
1259 struct scrub_dev *sdev = sblock->sdev;
1260 u8 csum[BTRFS_CSUM_SIZE];
1261 u8 *on_disk_csum;
1262 struct page *page;
1263 void *buffer;
1264 u32 crc = ~(u32)0;
1265 int fail = 0;
1266 struct btrfs_root *root = sdev->dev->dev_root;
1267 u64 len;
1268 int index;
1269
1270 BUG_ON(sblock->page_count < 1);
1271 if (!sblock->pagev[0].have_csum)
1272 return 0;
1273
1274 on_disk_csum = sblock->pagev[0].csum;
1275 page = sblock->pagev[0].page;
1276 buffer = kmap_atomic(page);
1277
1278 len = sdev->sectorsize;
1279 index = 0;
1280 for (;;) {
1281 u64 l = min_t(u64, len, PAGE_SIZE);
1282
1283 crc = btrfs_csum_data(root, buffer, crc, l);
1284 kunmap_atomic(buffer);
1285 len -= l;
1286 if (len == 0)
1287 break;
1288 index++;
1289 BUG_ON(index >= sblock->page_count);
1290 BUG_ON(!sblock->pagev[index].page);
1291 page = sblock->pagev[index].page;
1292 buffer = kmap_atomic(page);
1293 }
1294
1295 btrfs_csum_final(crc, csum);
1296 if (memcmp(csum, on_disk_csum, sdev->csum_size))
1297 fail = 1;
1298
1299 return fail;
1300}
1301
1302static int scrub_checksum_tree_block(struct scrub_block *sblock)
1303{
1304 struct scrub_dev *sdev = sblock->sdev;
1305 struct btrfs_header *h;
1306 struct btrfs_root *root = sdev->dev->dev_root;
1307 struct btrfs_fs_info *fs_info = root->fs_info;
1308 u8 calculated_csum[BTRFS_CSUM_SIZE];
1309 u8 on_disk_csum[BTRFS_CSUM_SIZE];
1310 struct page *page;
1311 void *mapped_buffer;
1312 u64 mapped_size;
1313 void *p;
1314 u32 crc = ~(u32)0;
1315 int fail = 0;
1316 int crc_fail = 0;
1317 u64 len;
1318 int index;
1319
1320 BUG_ON(sblock->page_count < 1);
1321 page = sblock->pagev[0].page;
1322 mapped_buffer = kmap_atomic(page);
1323 h = (struct btrfs_header *)mapped_buffer;
1324 memcpy(on_disk_csum, h->csum, sdev->csum_size);
1325
1326 /*
1327 * we don't use the getter functions here, as we
1328 * a) don't have an extent buffer and
1329 * b) the page is already kmapped
1330 */
1331
1332 if (sblock->pagev[0].logical != le64_to_cpu(h->bytenr))
1333 ++fail;
1334
1335 if (sblock->pagev[0].generation != le64_to_cpu(h->generation))
1336 ++fail;
1337
1338 if (memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
1339 ++fail;
1340
1341 if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
1342 BTRFS_UUID_SIZE))
1343 ++fail;
1344
1345 BUG_ON(sdev->nodesize != sdev->leafsize);
1346 len = sdev->nodesize - BTRFS_CSUM_SIZE;
1347 mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
1348 p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
1349 index = 0;
1350 for (;;) {
1351 u64 l = min_t(u64, len, mapped_size);
1352
1353 crc = btrfs_csum_data(root, p, crc, l);
1354 kunmap_atomic(mapped_buffer);
1355 len -= l;
1356 if (len == 0)
1357 break;
1358 index++;
1359 BUG_ON(index >= sblock->page_count);
1360 BUG_ON(!sblock->pagev[index].page);
1361 page = sblock->pagev[index].page;
1362 mapped_buffer = kmap_atomic(page);
1363 mapped_size = PAGE_SIZE;
1364 p = mapped_buffer;
1365 }
1366
1367 btrfs_csum_final(crc, calculated_csum);
1368 if (memcmp(calculated_csum, on_disk_csum, sdev->csum_size))
1369 ++crc_fail;
1370
1371 return fail || crc_fail;
1372}
1373
1374static int scrub_checksum_super(struct scrub_block *sblock)
1375{
1376 struct btrfs_super_block *s;
1377 struct scrub_dev *sdev = sblock->sdev;
1378 struct btrfs_root *root = sdev->dev->dev_root;
1379 struct btrfs_fs_info *fs_info = root->fs_info;
1380 u8 calculated_csum[BTRFS_CSUM_SIZE];
1381 u8 on_disk_csum[BTRFS_CSUM_SIZE];
1382 struct page *page;
1383 void *mapped_buffer;
1384 u64 mapped_size;
1385 void *p;
1386 u32 crc = ~(u32)0;
1387 int fail_gen = 0;
1388 int fail_cor = 0;
1389 u64 len;
1390 int index;
1391
1392 BUG_ON(sblock->page_count < 1);
1393 page = sblock->pagev[0].page;
1394 mapped_buffer = kmap_atomic(page);
1395 s = (struct btrfs_super_block *)mapped_buffer;
1396 memcpy(on_disk_csum, s->csum, sdev->csum_size);
1397
1398 if (sblock->pagev[0].logical != le64_to_cpu(s->bytenr))
1399 ++fail_cor;
1400
1401 if (sblock->pagev[0].generation != le64_to_cpu(s->generation))
1402 ++fail_gen;
1403
1404 if (memcmp(s->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
1405 ++fail_cor;
1406
1407 len = BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE;
1408 mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
1409 p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
1410 index = 0;
1411 for (;;) {
1412 u64 l = min_t(u64, len, mapped_size);
1413
1414 crc = btrfs_csum_data(root, p, crc, l);
1415 kunmap_atomic(mapped_buffer);
1416 len -= l;
1417 if (len == 0)
1418 break;
1419 index++;
1420 BUG_ON(index >= sblock->page_count);
1421 BUG_ON(!sblock->pagev[index].page);
1422 page = sblock->pagev[index].page;
1423 mapped_buffer = kmap_atomic(page);
1424 mapped_size = PAGE_SIZE;
1425 p = mapped_buffer;
1426 }
1427
1428 btrfs_csum_final(crc, calculated_csum);
1429 if (memcmp(calculated_csum, on_disk_csum, sdev->csum_size))
1430 ++fail_cor;
1431
1432 if (fail_cor + fail_gen) {
1433 /*
1434 * if we find an error in a super block, we just report it.
1435 * They will get written with the next transaction commit
1436 * anyway
1437 */
1438 spin_lock(&sdev->stat_lock);
1439 ++sdev->stat.super_errors;
1440 spin_unlock(&sdev->stat_lock);
1441 if (fail_cor)
1442 btrfs_dev_stat_inc_and_print(sdev->dev,
1443 BTRFS_DEV_STAT_CORRUPTION_ERRS);
1444 else
1445 btrfs_dev_stat_inc_and_print(sdev->dev,
1446 BTRFS_DEV_STAT_GENERATION_ERRS);
1447 }
1448
1449 return fail_cor + fail_gen;
1450}
1451
1452static void scrub_block_get(struct scrub_block *sblock)
1453{
1454 atomic_inc(&sblock->ref_count);
1455}
1456
1457static void scrub_block_put(struct scrub_block *sblock)
1458{
1459 if (atomic_dec_and_test(&sblock->ref_count)) {
1460 int i;
1461
1462 for (i = 0; i < sblock->page_count; i++)
1463 if (sblock->pagev[i].page)
1464 __free_page(sblock->pagev[i].page);
1465 kfree(sblock);
1466 }
1467}
1468
1469static void scrub_submit(struct scrub_dev *sdev)
1470{
1471 struct scrub_bio *sbio;
1472
1473 if (sdev->curr == -1)
1474 return;
1475
1476 sbio = sdev->bios[sdev->curr];
1477 sdev->curr = -1;
1478 atomic_inc(&sdev->in_flight);
1479
1480 btrfsic_submit_bio(READ, sbio->bio);
1481}
1482
1483static int scrub_add_page_to_bio(struct scrub_dev *sdev,
1484 struct scrub_page *spage)
1485{
1486 struct scrub_block *sblock = spage->sblock;
1487 struct scrub_bio *sbio;
1488 int ret;
1489
1490again:
1491 /*
1492 * grab a fresh bio or wait for one to become available
1493 */
1494 while (sdev->curr == -1) {
1495 spin_lock(&sdev->list_lock);
1496 sdev->curr = sdev->first_free;
1497 if (sdev->curr != -1) {
1498 sdev->first_free = sdev->bios[sdev->curr]->next_free;
1499 sdev->bios[sdev->curr]->next_free = -1;
1500 sdev->bios[sdev->curr]->page_count = 0;
1501 spin_unlock(&sdev->list_lock);
1502 } else {
1503 spin_unlock(&sdev->list_lock);
1504 wait_event(sdev->list_wait, sdev->first_free != -1);
1505 }
1506 }
1507 sbio = sdev->bios[sdev->curr];
1508 if (sbio->page_count == 0) {
1509 struct bio *bio;
1510
1511 sbio->physical = spage->physical;
1512 sbio->logical = spage->logical;
1513 bio = sbio->bio;
1514 if (!bio) {
1515 bio = bio_alloc(GFP_NOFS, sdev->pages_per_bio);
1516 if (!bio)
1517 return -ENOMEM;
1518 sbio->bio = bio;
1519 }
1520
1521 bio->bi_private = sbio;
1522 bio->bi_end_io = scrub_bio_end_io;
1523 bio->bi_bdev = sdev->dev->bdev;
1524 bio->bi_sector = spage->physical >> 9;
1525 sbio->err = 0;
1526 } else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
1527 spage->physical ||
1528 sbio->logical + sbio->page_count * PAGE_SIZE !=
1529 spage->logical) {
1530 scrub_submit(sdev);
1531 goto again;
1532 }
1533
1534 sbio->pagev[sbio->page_count] = spage;
1535 ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0);
1536 if (ret != PAGE_SIZE) {
1537 if (sbio->page_count < 1) {
1538 bio_put(sbio->bio);
1539 sbio->bio = NULL;
1540 return -EIO;
1541 }
1542 scrub_submit(sdev);
1543 goto again;
1544 }
1545
1546 scrub_block_get(sblock); /* one for the added page */
1547 atomic_inc(&sblock->outstanding_pages);
1548 sbio->page_count++;
1549 if (sbio->page_count == sdev->pages_per_bio)
1550 scrub_submit(sdev);
1551
1552 return 0;
1553}
1554
1555static int scrub_pages(struct scrub_dev *sdev, u64 logical, u64 len,
1556 u64 physical, u64 flags, u64 gen, int mirror_num,
1557 u8 *csum, int force)
1558{
1559 struct scrub_block *sblock;
1560 int index;
1561
1562 sblock = kzalloc(sizeof(*sblock), GFP_NOFS);
1563 if (!sblock) {
1564 spin_lock(&sdev->stat_lock);
1565 sdev->stat.malloc_errors++;
1566 spin_unlock(&sdev->stat_lock);
1567 return -ENOMEM;
1568 }
1569
1570 /* one ref inside this function, plus one for each page later on */
1571 atomic_set(&sblock->ref_count, 1);
1572 sblock->sdev = sdev;
1573 sblock->no_io_error_seen = 1;
1574
1575 for (index = 0; len > 0; index++) {
1576 struct scrub_page *spage = sblock->pagev + index;
1577 u64 l = min_t(u64, len, PAGE_SIZE);
1578
1579 BUG_ON(index >= SCRUB_MAX_PAGES_PER_BLOCK);
1580 spage->page = alloc_page(GFP_NOFS);
1581 if (!spage->page) {
1582 spin_lock(&sdev->stat_lock);
1583 sdev->stat.malloc_errors++;
1584 spin_unlock(&sdev->stat_lock);
1585 while (index > 0) {
1586 index--;
1587 __free_page(sblock->pagev[index].page);
1588 }
1589 kfree(sblock);
1590 return -ENOMEM;
1591 }
1592 spage->sblock = sblock;
1593 spage->dev = sdev->dev;
1594 spage->flags = flags;
1595 spage->generation = gen;
1596 spage->logical = logical;
1597 spage->physical = physical;
1598 spage->mirror_num = mirror_num;
1599 if (csum) {
1600 spage->have_csum = 1;
1601 memcpy(spage->csum, csum, sdev->csum_size);
1602 } else {
1603 spage->have_csum = 0;
1604 }
1605 sblock->page_count++;
1606 len -= l;
1607 logical += l;
1608 physical += l;
1609 }
1610
1611 BUG_ON(sblock->page_count == 0);
1612 for (index = 0; index < sblock->page_count; index++) {
1613 struct scrub_page *spage = sblock->pagev + index;
1614 int ret;
1615
1616 ret = scrub_add_page_to_bio(sdev, spage);
1617 if (ret) {
1618 scrub_block_put(sblock);
1619 return ret;
1620 }
1621 }
1622
1623 if (force)
1624 scrub_submit(sdev);
1625
1626 /* last one frees, either here or in bio completion for last page */
1627 scrub_block_put(sblock);
1628 return 0;
1629}
1630
1631static void scrub_bio_end_io(struct bio *bio, int err)
1632{
1633 struct scrub_bio *sbio = bio->bi_private;
1634 struct scrub_dev *sdev = sbio->sdev;
1635 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
1636
1637 sbio->err = err;
1638 sbio->bio = bio;
1639
1640 btrfs_queue_worker(&fs_info->scrub_workers, &sbio->work);
1641}
1642
1643static void scrub_bio_end_io_worker(struct btrfs_work *work)
1644{
1645 struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
1646 struct scrub_dev *sdev = sbio->sdev;
1647 int i;
1648
1649 BUG_ON(sbio->page_count > SCRUB_PAGES_PER_BIO);
1650 if (sbio->err) {
1651 for (i = 0; i < sbio->page_count; i++) {
1652 struct scrub_page *spage = sbio->pagev[i];
1653
1654 spage->io_error = 1;
1655 spage->sblock->no_io_error_seen = 0;
1656 }
1657 }
1658
1659 /* now complete the scrub_block items that have all pages completed */
1660 for (i = 0; i < sbio->page_count; i++) {
1661 struct scrub_page *spage = sbio->pagev[i];
1662 struct scrub_block *sblock = spage->sblock;
1663
1664 if (atomic_dec_and_test(&sblock->outstanding_pages))
1665 scrub_block_complete(sblock);
1666 scrub_block_put(sblock);
1667 }
1668
1669 if (sbio->err) {
1670 /* what is this good for??? */
1671 sbio->bio->bi_flags &= ~(BIO_POOL_MASK - 1);
1672 sbio->bio->bi_flags |= 1 << BIO_UPTODATE;
1673 sbio->bio->bi_phys_segments = 0;
1674 sbio->bio->bi_idx = 0;
1675
1676 for (i = 0; i < sbio->page_count; i++) {
1677 struct bio_vec *bi;
1678 bi = &sbio->bio->bi_io_vec[i];
1679 bi->bv_offset = 0;
1680 bi->bv_len = PAGE_SIZE;
1681 }
1682 }
1683
1684 bio_put(sbio->bio);
1685 sbio->bio = NULL;
1686 spin_lock(&sdev->list_lock);
1687 sbio->next_free = sdev->first_free;
1688 sdev->first_free = sbio->index;
1689 spin_unlock(&sdev->list_lock);
1690 atomic_dec(&sdev->in_flight);
1691 wake_up(&sdev->list_wait);
1692}
1693
1694static void scrub_block_complete(struct scrub_block *sblock)
1695{
1696 if (!sblock->no_io_error_seen)
1697 scrub_handle_errored_block(sblock);
1698 else
1699 scrub_checksum(sblock);
1700}
1701
1702static int scrub_find_csum(struct scrub_dev *sdev, u64 logical, u64 len,
1703 u8 *csum)
1704{
1705 struct btrfs_ordered_sum *sum = NULL;
1706 int ret = 0;
1707 unsigned long i;
1708 unsigned long num_sectors;
1709
1710 while (!list_empty(&sdev->csum_list)) {
1711 sum = list_first_entry(&sdev->csum_list,
1712 struct btrfs_ordered_sum, list);
1713 if (sum->bytenr > logical)
1714 return 0;
1715 if (sum->bytenr + sum->len > logical)
1716 break;
1717
1718 ++sdev->stat.csum_discards;
1719 list_del(&sum->list);
1720 kfree(sum);
1721 sum = NULL;
1722 }
1723 if (!sum)
1724 return 0;
1725
1726 num_sectors = sum->len / sdev->sectorsize;
1727 for (i = 0; i < num_sectors; ++i) {
1728 if (sum->sums[i].bytenr == logical) {
1729 memcpy(csum, &sum->sums[i].sum, sdev->csum_size);
1730 ret = 1;
1731 break;
1732 }
1733 }
1734 if (ret && i == num_sectors - 1) {
1735 list_del(&sum->list);
1736 kfree(sum);
1737 }
1738 return ret;
1739}
1740
1741/* scrub extent tries to collect up to 64 kB for each bio */
1742static int scrub_extent(struct scrub_dev *sdev, u64 logical, u64 len,
1743 u64 physical, u64 flags, u64 gen, int mirror_num)
1744{
1745 int ret;
1746 u8 csum[BTRFS_CSUM_SIZE];
1747 u32 blocksize;
1748
1749 if (flags & BTRFS_EXTENT_FLAG_DATA) {
1750 blocksize = sdev->sectorsize;
1751 spin_lock(&sdev->stat_lock);
1752 sdev->stat.data_extents_scrubbed++;
1753 sdev->stat.data_bytes_scrubbed += len;
1754 spin_unlock(&sdev->stat_lock);
1755 } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1756 BUG_ON(sdev->nodesize != sdev->leafsize);
1757 blocksize = sdev->nodesize;
1758 spin_lock(&sdev->stat_lock);
1759 sdev->stat.tree_extents_scrubbed++;
1760 sdev->stat.tree_bytes_scrubbed += len;
1761 spin_unlock(&sdev->stat_lock);
1762 } else {
1763 blocksize = sdev->sectorsize;
1764 BUG_ON(1);
1765 }
1766
1767 while (len) {
1768 u64 l = min_t(u64, len, blocksize);
1769 int have_csum = 0;
1770
1771 if (flags & BTRFS_EXTENT_FLAG_DATA) {
1772 /* push csums to sbio */
1773 have_csum = scrub_find_csum(sdev, logical, l, csum);
1774 if (have_csum == 0)
1775 ++sdev->stat.no_csum;
1776 }
1777 ret = scrub_pages(sdev, logical, l, physical, flags, gen,
1778 mirror_num, have_csum ? csum : NULL, 0);
1779 if (ret)
1780 return ret;
1781 len -= l;
1782 logical += l;
1783 physical += l;
1784 }
1785 return 0;
1786}
1787
1788static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev,
1789 struct map_lookup *map, int num, u64 base, u64 length)
1790{
1791 struct btrfs_path *path;
1792 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
1793 struct btrfs_root *root = fs_info->extent_root;
1794 struct btrfs_root *csum_root = fs_info->csum_root;
1795 struct btrfs_extent_item *extent;
1796 struct blk_plug plug;
1797 u64 flags;
1798 int ret;
1799 int slot;
1800 int i;
1801 u64 nstripes;
1802 struct extent_buffer *l;
1803 struct btrfs_key key;
1804 u64 physical;
1805 u64 logical;
1806 u64 generation;
1807 int mirror_num;
1808 struct reada_control *reada1;
1809 struct reada_control *reada2;
1810 struct btrfs_key key_start;
1811 struct btrfs_key key_end;
1812
1813 u64 increment = map->stripe_len;
1814 u64 offset;
1815
1816 nstripes = length;
1817 offset = 0;
1818 do_div(nstripes, map->stripe_len);
1819 if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
1820 offset = map->stripe_len * num;
1821 increment = map->stripe_len * map->num_stripes;
1822 mirror_num = 1;
1823 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1824 int factor = map->num_stripes / map->sub_stripes;
1825 offset = map->stripe_len * (num / map->sub_stripes);
1826 increment = map->stripe_len * factor;
1827 mirror_num = num % map->sub_stripes + 1;
1828 } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
1829 increment = map->stripe_len;
1830 mirror_num = num % map->num_stripes + 1;
1831 } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
1832 increment = map->stripe_len;
1833 mirror_num = num % map->num_stripes + 1;
1834 } else {
1835 increment = map->stripe_len;
1836 mirror_num = 1;
1837 }
1838
1839 path = btrfs_alloc_path();
1840 if (!path)
1841 return -ENOMEM;
1842
1843 /*
1844 * work on commit root. The related disk blocks are static as
1845 * long as COW is applied. This means, it is save to rewrite
1846 * them to repair disk errors without any race conditions
1847 */
1848 path->search_commit_root = 1;
1849 path->skip_locking = 1;
1850
1851 /*
1852 * trigger the readahead for extent tree csum tree and wait for
1853 * completion. During readahead, the scrub is officially paused
1854 * to not hold off transaction commits
1855 */
1856 logical = base + offset;
1857
1858 wait_event(sdev->list_wait,
1859 atomic_read(&sdev->in_flight) == 0);
1860 atomic_inc(&fs_info->scrubs_paused);
1861 wake_up(&fs_info->scrub_pause_wait);
1862
1863 /* FIXME it might be better to start readahead at commit root */
1864 key_start.objectid = logical;
1865 key_start.type = BTRFS_EXTENT_ITEM_KEY;
1866 key_start.offset = (u64)0;
1867 key_end.objectid = base + offset + nstripes * increment;
1868 key_end.type = BTRFS_EXTENT_ITEM_KEY;
1869 key_end.offset = (u64)0;
1870 reada1 = btrfs_reada_add(root, &key_start, &key_end);
1871
1872 key_start.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
1873 key_start.type = BTRFS_EXTENT_CSUM_KEY;
1874 key_start.offset = logical;
1875 key_end.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
1876 key_end.type = BTRFS_EXTENT_CSUM_KEY;
1877 key_end.offset = base + offset + nstripes * increment;
1878 reada2 = btrfs_reada_add(csum_root, &key_start, &key_end);
1879
1880 if (!IS_ERR(reada1))
1881 btrfs_reada_wait(reada1);
1882 if (!IS_ERR(reada2))
1883 btrfs_reada_wait(reada2);
1884
1885 mutex_lock(&fs_info->scrub_lock);
1886 while (atomic_read(&fs_info->scrub_pause_req)) {
1887 mutex_unlock(&fs_info->scrub_lock);
1888 wait_event(fs_info->scrub_pause_wait,
1889 atomic_read(&fs_info->scrub_pause_req) == 0);
1890 mutex_lock(&fs_info->scrub_lock);
1891 }
1892 atomic_dec(&fs_info->scrubs_paused);
1893 mutex_unlock(&fs_info->scrub_lock);
1894 wake_up(&fs_info->scrub_pause_wait);
1895
1896 /*
1897 * collect all data csums for the stripe to avoid seeking during
1898 * the scrub. This might currently (crc32) end up to be about 1MB
1899 */
1900 blk_start_plug(&plug);
1901
1902 /*
1903 * now find all extents for each stripe and scrub them
1904 */
1905 logical = base + offset;
1906 physical = map->stripes[num].physical;
1907 ret = 0;
1908 for (i = 0; i < nstripes; ++i) {
1909 /*
1910 * canceled?
1911 */
1912 if (atomic_read(&fs_info->scrub_cancel_req) ||
1913 atomic_read(&sdev->cancel_req)) {
1914 ret = -ECANCELED;
1915 goto out;
1916 }
1917 /*
1918 * check to see if we have to pause
1919 */
1920 if (atomic_read(&fs_info->scrub_pause_req)) {
1921 /* push queued extents */
1922 scrub_submit(sdev);
1923 wait_event(sdev->list_wait,
1924 atomic_read(&sdev->in_flight) == 0);
1925 atomic_inc(&fs_info->scrubs_paused);
1926 wake_up(&fs_info->scrub_pause_wait);
1927 mutex_lock(&fs_info->scrub_lock);
1928 while (atomic_read(&fs_info->scrub_pause_req)) {
1929 mutex_unlock(&fs_info->scrub_lock);
1930 wait_event(fs_info->scrub_pause_wait,
1931 atomic_read(&fs_info->scrub_pause_req) == 0);
1932 mutex_lock(&fs_info->scrub_lock);
1933 }
1934 atomic_dec(&fs_info->scrubs_paused);
1935 mutex_unlock(&fs_info->scrub_lock);
1936 wake_up(&fs_info->scrub_pause_wait);
1937 }
1938
1939 ret = btrfs_lookup_csums_range(csum_root, logical,
1940 logical + map->stripe_len - 1,
1941 &sdev->csum_list, 1);
1942 if (ret)
1943 goto out;
1944
1945 key.objectid = logical;
1946 key.type = BTRFS_EXTENT_ITEM_KEY;
1947 key.offset = (u64)0;
1948
1949 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1950 if (ret < 0)
1951 goto out;
1952 if (ret > 0) {
1953 ret = btrfs_previous_item(root, path, 0,
1954 BTRFS_EXTENT_ITEM_KEY);
1955 if (ret < 0)
1956 goto out;
1957 if (ret > 0) {
1958 /* there's no smaller item, so stick with the
1959 * larger one */
1960 btrfs_release_path(path);
1961 ret = btrfs_search_slot(NULL, root, &key,
1962 path, 0, 0);
1963 if (ret < 0)
1964 goto out;
1965 }
1966 }
1967
1968 while (1) {
1969 l = path->nodes[0];
1970 slot = path->slots[0];
1971 if (slot >= btrfs_header_nritems(l)) {
1972 ret = btrfs_next_leaf(root, path);
1973 if (ret == 0)
1974 continue;
1975 if (ret < 0)
1976 goto out;
1977
1978 break;
1979 }
1980 btrfs_item_key_to_cpu(l, &key, slot);
1981
1982 if (key.objectid + key.offset <= logical)
1983 goto next;
1984
1985 if (key.objectid >= logical + map->stripe_len)
1986 break;
1987
1988 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY)
1989 goto next;
1990
1991 extent = btrfs_item_ptr(l, slot,
1992 struct btrfs_extent_item);
1993 flags = btrfs_extent_flags(l, extent);
1994 generation = btrfs_extent_generation(l, extent);
1995
1996 if (key.objectid < logical &&
1997 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) {
1998 printk(KERN_ERR
1999 "btrfs scrub: tree block %llu spanning "
2000 "stripes, ignored. logical=%llu\n",
2001 (unsigned long long)key.objectid,
2002 (unsigned long long)logical);
2003 goto next;
2004 }
2005
2006 /*
2007 * trim extent to this stripe
2008 */
2009 if (key.objectid < logical) {
2010 key.offset -= logical - key.objectid;
2011 key.objectid = logical;
2012 }
2013 if (key.objectid + key.offset >
2014 logical + map->stripe_len) {
2015 key.offset = logical + map->stripe_len -
2016 key.objectid;
2017 }
2018
2019 ret = scrub_extent(sdev, key.objectid, key.offset,
2020 key.objectid - logical + physical,
2021 flags, generation, mirror_num);
2022 if (ret)
2023 goto out;
2024
2025next:
2026 path->slots[0]++;
2027 }
2028 btrfs_release_path(path);
2029 logical += increment;
2030 physical += map->stripe_len;
2031 spin_lock(&sdev->stat_lock);
2032 sdev->stat.last_physical = physical;
2033 spin_unlock(&sdev->stat_lock);
2034 }
2035 /* push queued extents */
2036 scrub_submit(sdev);
2037
2038out:
2039 blk_finish_plug(&plug);
2040 btrfs_free_path(path);
2041 return ret < 0 ? ret : 0;
2042}
2043
2044static noinline_for_stack int scrub_chunk(struct scrub_dev *sdev,
2045 u64 chunk_tree, u64 chunk_objectid, u64 chunk_offset, u64 length,
2046 u64 dev_offset)
2047{
2048 struct btrfs_mapping_tree *map_tree =
2049 &sdev->dev->dev_root->fs_info->mapping_tree;
2050 struct map_lookup *map;
2051 struct extent_map *em;
2052 int i;
2053 int ret = -EINVAL;
2054
2055 read_lock(&map_tree->map_tree.lock);
2056 em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
2057 read_unlock(&map_tree->map_tree.lock);
2058
2059 if (!em)
2060 return -EINVAL;
2061
2062 map = (struct map_lookup *)em->bdev;
2063 if (em->start != chunk_offset)
2064 goto out;
2065
2066 if (em->len < length)
2067 goto out;
2068
2069 for (i = 0; i < map->num_stripes; ++i) {
2070 if (map->stripes[i].dev == sdev->dev &&
2071 map->stripes[i].physical == dev_offset) {
2072 ret = scrub_stripe(sdev, map, i, chunk_offset, length);
2073 if (ret)
2074 goto out;
2075 }
2076 }
2077out:
2078 free_extent_map(em);
2079
2080 return ret;
2081}
2082
2083static noinline_for_stack
2084int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end)
2085{
2086 struct btrfs_dev_extent *dev_extent = NULL;
2087 struct btrfs_path *path;
2088 struct btrfs_root *root = sdev->dev->dev_root;
2089 struct btrfs_fs_info *fs_info = root->fs_info;
2090 u64 length;
2091 u64 chunk_tree;
2092 u64 chunk_objectid;
2093 u64 chunk_offset;
2094 int ret;
2095 int slot;
2096 struct extent_buffer *l;
2097 struct btrfs_key key;
2098 struct btrfs_key found_key;
2099 struct btrfs_block_group_cache *cache;
2100
2101 path = btrfs_alloc_path();
2102 if (!path)
2103 return -ENOMEM;
2104
2105 path->reada = 2;
2106 path->search_commit_root = 1;
2107 path->skip_locking = 1;
2108
2109 key.objectid = sdev->dev->devid;
2110 key.offset = 0ull;
2111 key.type = BTRFS_DEV_EXTENT_KEY;
2112
2113
2114 while (1) {
2115 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2116 if (ret < 0)
2117 break;
2118 if (ret > 0) {
2119 if (path->slots[0] >=
2120 btrfs_header_nritems(path->nodes[0])) {
2121 ret = btrfs_next_leaf(root, path);
2122 if (ret)
2123 break;
2124 }
2125 }
2126
2127 l = path->nodes[0];
2128 slot = path->slots[0];
2129
2130 btrfs_item_key_to_cpu(l, &found_key, slot);
2131
2132 if (found_key.objectid != sdev->dev->devid)
2133 break;
2134
2135 if (btrfs_key_type(&found_key) != BTRFS_DEV_EXTENT_KEY)
2136 break;
2137
2138 if (found_key.offset >= end)
2139 break;
2140
2141 if (found_key.offset < key.offset)
2142 break;
2143
2144 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
2145 length = btrfs_dev_extent_length(l, dev_extent);
2146
2147 if (found_key.offset + length <= start) {
2148 key.offset = found_key.offset + length;
2149 btrfs_release_path(path);
2150 continue;
2151 }
2152
2153 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
2154 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
2155 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
2156
2157 /*
2158 * get a reference on the corresponding block group to prevent
2159 * the chunk from going away while we scrub it
2160 */
2161 cache = btrfs_lookup_block_group(fs_info, chunk_offset);
2162 if (!cache) {
2163 ret = -ENOENT;
2164 break;
2165 }
2166 ret = scrub_chunk(sdev, chunk_tree, chunk_objectid,
2167 chunk_offset, length, found_key.offset);
2168 btrfs_put_block_group(cache);
2169 if (ret)
2170 break;
2171
2172 key.offset = found_key.offset + length;
2173 btrfs_release_path(path);
2174 }
2175
2176 btrfs_free_path(path);
2177
2178 /*
2179 * ret can still be 1 from search_slot or next_leaf,
2180 * that's not an error
2181 */
2182 return ret < 0 ? ret : 0;
2183}
2184
2185static noinline_for_stack int scrub_supers(struct scrub_dev *sdev)
2186{
2187 int i;
2188 u64 bytenr;
2189 u64 gen;
2190 int ret;
2191 struct btrfs_device *device = sdev->dev;
2192 struct btrfs_root *root = device->dev_root;
2193
2194 if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
2195 return -EIO;
2196
2197 gen = root->fs_info->last_trans_committed;
2198
2199 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
2200 bytenr = btrfs_sb_offset(i);
2201 if (bytenr + BTRFS_SUPER_INFO_SIZE > device->total_bytes)
2202 break;
2203
2204 ret = scrub_pages(sdev, bytenr, BTRFS_SUPER_INFO_SIZE, bytenr,
2205 BTRFS_EXTENT_FLAG_SUPER, gen, i, NULL, 1);
2206 if (ret)
2207 return ret;
2208 }
2209 wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
2210
2211 return 0;
2212}
2213
2214/*
2215 * get a reference count on fs_info->scrub_workers. start worker if necessary
2216 */
2217static noinline_for_stack int scrub_workers_get(struct btrfs_root *root)
2218{
2219 struct btrfs_fs_info *fs_info = root->fs_info;
2220 int ret = 0;
2221
2222 mutex_lock(&fs_info->scrub_lock);
2223 if (fs_info->scrub_workers_refcnt == 0) {
2224 btrfs_init_workers(&fs_info->scrub_workers, "scrub",
2225 fs_info->thread_pool_size, &fs_info->generic_worker);
2226 fs_info->scrub_workers.idle_thresh = 4;
2227 ret = btrfs_start_workers(&fs_info->scrub_workers);
2228 if (ret)
2229 goto out;
2230 }
2231 ++fs_info->scrub_workers_refcnt;
2232out:
2233 mutex_unlock(&fs_info->scrub_lock);
2234
2235 return ret;
2236}
2237
2238static noinline_for_stack void scrub_workers_put(struct btrfs_root *root)
2239{
2240 struct btrfs_fs_info *fs_info = root->fs_info;
2241
2242 mutex_lock(&fs_info->scrub_lock);
2243 if (--fs_info->scrub_workers_refcnt == 0)
2244 btrfs_stop_workers(&fs_info->scrub_workers);
2245 WARN_ON(fs_info->scrub_workers_refcnt < 0);
2246 mutex_unlock(&fs_info->scrub_lock);
2247}
2248
2249
2250int btrfs_scrub_dev(struct btrfs_root *root, u64 devid, u64 start, u64 end,
2251 struct btrfs_scrub_progress *progress, int readonly)
2252{
2253 struct scrub_dev *sdev;
2254 struct btrfs_fs_info *fs_info = root->fs_info;
2255 int ret;
2256 struct btrfs_device *dev;
2257
2258 if (btrfs_fs_closing(root->fs_info))
2259 return -EINVAL;
2260
2261 /*
2262 * check some assumptions
2263 */
2264 if (root->nodesize != root->leafsize) {
2265 printk(KERN_ERR
2266 "btrfs_scrub: size assumption nodesize == leafsize (%d == %d) fails\n",
2267 root->nodesize, root->leafsize);
2268 return -EINVAL;
2269 }
2270
2271 if (root->nodesize > BTRFS_STRIPE_LEN) {
2272 /*
2273 * in this case scrub is unable to calculate the checksum
2274 * the way scrub is implemented. Do not handle this
2275 * situation at all because it won't ever happen.
2276 */
2277 printk(KERN_ERR
2278 "btrfs_scrub: size assumption nodesize <= BTRFS_STRIPE_LEN (%d <= %d) fails\n",
2279 root->nodesize, BTRFS_STRIPE_LEN);
2280 return -EINVAL;
2281 }
2282
2283 if (root->sectorsize != PAGE_SIZE) {
2284 /* not supported for data w/o checksums */
2285 printk(KERN_ERR
2286 "btrfs_scrub: size assumption sectorsize != PAGE_SIZE (%d != %lld) fails\n",
2287 root->sectorsize, (unsigned long long)PAGE_SIZE);
2288 return -EINVAL;
2289 }
2290
2291 ret = scrub_workers_get(root);
2292 if (ret)
2293 return ret;
2294
2295 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2296 dev = btrfs_find_device(root, devid, NULL, NULL);
2297 if (!dev || dev->missing) {
2298 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2299 scrub_workers_put(root);
2300 return -ENODEV;
2301 }
2302 mutex_lock(&fs_info->scrub_lock);
2303
2304 if (!dev->in_fs_metadata) {
2305 mutex_unlock(&fs_info->scrub_lock);
2306 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2307 scrub_workers_put(root);
2308 return -ENODEV;
2309 }
2310
2311 if (dev->scrub_device) {
2312 mutex_unlock(&fs_info->scrub_lock);
2313 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2314 scrub_workers_put(root);
2315 return -EINPROGRESS;
2316 }
2317 sdev = scrub_setup_dev(dev);
2318 if (IS_ERR(sdev)) {
2319 mutex_unlock(&fs_info->scrub_lock);
2320 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2321 scrub_workers_put(root);
2322 return PTR_ERR(sdev);
2323 }
2324 sdev->readonly = readonly;
2325 dev->scrub_device = sdev;
2326
2327 atomic_inc(&fs_info->scrubs_running);
2328 mutex_unlock(&fs_info->scrub_lock);
2329 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2330
2331 down_read(&fs_info->scrub_super_lock);
2332 ret = scrub_supers(sdev);
2333 up_read(&fs_info->scrub_super_lock);
2334
2335 if (!ret)
2336 ret = scrub_enumerate_chunks(sdev, start, end);
2337
2338 wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
2339 atomic_dec(&fs_info->scrubs_running);
2340 wake_up(&fs_info->scrub_pause_wait);
2341
2342 wait_event(sdev->list_wait, atomic_read(&sdev->fixup_cnt) == 0);
2343
2344 if (progress)
2345 memcpy(progress, &sdev->stat, sizeof(*progress));
2346
2347 mutex_lock(&fs_info->scrub_lock);
2348 dev->scrub_device = NULL;
2349 mutex_unlock(&fs_info->scrub_lock);
2350
2351 scrub_free_dev(sdev);
2352 scrub_workers_put(root);
2353
2354 return ret;
2355}
2356
2357void btrfs_scrub_pause(struct btrfs_root *root)
2358{
2359 struct btrfs_fs_info *fs_info = root->fs_info;
2360
2361 mutex_lock(&fs_info->scrub_lock);
2362 atomic_inc(&fs_info->scrub_pause_req);
2363 while (atomic_read(&fs_info->scrubs_paused) !=
2364 atomic_read(&fs_info->scrubs_running)) {
2365 mutex_unlock(&fs_info->scrub_lock);
2366 wait_event(fs_info->scrub_pause_wait,
2367 atomic_read(&fs_info->scrubs_paused) ==
2368 atomic_read(&fs_info->scrubs_running));
2369 mutex_lock(&fs_info->scrub_lock);
2370 }
2371 mutex_unlock(&fs_info->scrub_lock);
2372}
2373
2374void btrfs_scrub_continue(struct btrfs_root *root)
2375{
2376 struct btrfs_fs_info *fs_info = root->fs_info;
2377
2378 atomic_dec(&fs_info->scrub_pause_req);
2379 wake_up(&fs_info->scrub_pause_wait);
2380}
2381
2382void btrfs_scrub_pause_super(struct btrfs_root *root)
2383{
2384 down_write(&root->fs_info->scrub_super_lock);
2385}
2386
2387void btrfs_scrub_continue_super(struct btrfs_root *root)
2388{
2389 up_write(&root->fs_info->scrub_super_lock);
2390}
2391
2392int __btrfs_scrub_cancel(struct btrfs_fs_info *fs_info)
2393{
2394
2395 mutex_lock(&fs_info->scrub_lock);
2396 if (!atomic_read(&fs_info->scrubs_running)) {
2397 mutex_unlock(&fs_info->scrub_lock);
2398 return -ENOTCONN;
2399 }
2400
2401 atomic_inc(&fs_info->scrub_cancel_req);
2402 while (atomic_read(&fs_info->scrubs_running)) {
2403 mutex_unlock(&fs_info->scrub_lock);
2404 wait_event(fs_info->scrub_pause_wait,
2405 atomic_read(&fs_info->scrubs_running) == 0);
2406 mutex_lock(&fs_info->scrub_lock);
2407 }
2408 atomic_dec(&fs_info->scrub_cancel_req);
2409 mutex_unlock(&fs_info->scrub_lock);
2410
2411 return 0;
2412}
2413
2414int btrfs_scrub_cancel(struct btrfs_root *root)
2415{
2416 return __btrfs_scrub_cancel(root->fs_info);
2417}
2418
2419int btrfs_scrub_cancel_dev(struct btrfs_root *root, struct btrfs_device *dev)
2420{
2421 struct btrfs_fs_info *fs_info = root->fs_info;
2422 struct scrub_dev *sdev;
2423
2424 mutex_lock(&fs_info->scrub_lock);
2425 sdev = dev->scrub_device;
2426 if (!sdev) {
2427 mutex_unlock(&fs_info->scrub_lock);
2428 return -ENOTCONN;
2429 }
2430 atomic_inc(&sdev->cancel_req);
2431 while (dev->scrub_device) {
2432 mutex_unlock(&fs_info->scrub_lock);
2433 wait_event(fs_info->scrub_pause_wait,
2434 dev->scrub_device == NULL);
2435 mutex_lock(&fs_info->scrub_lock);
2436 }
2437 mutex_unlock(&fs_info->scrub_lock);
2438
2439 return 0;
2440}
2441
2442int btrfs_scrub_cancel_devid(struct btrfs_root *root, u64 devid)
2443{
2444 struct btrfs_fs_info *fs_info = root->fs_info;
2445 struct btrfs_device *dev;
2446 int ret;
2447
2448 /*
2449 * we have to hold the device_list_mutex here so the device
2450 * does not go away in cancel_dev. FIXME: find a better solution
2451 */
2452 mutex_lock(&fs_info->fs_devices->device_list_mutex);
2453 dev = btrfs_find_device(root, devid, NULL, NULL);
2454 if (!dev) {
2455 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2456 return -ENODEV;
2457 }
2458 ret = btrfs_scrub_cancel_dev(root, dev);
2459 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2460
2461 return ret;
2462}
2463
2464int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
2465 struct btrfs_scrub_progress *progress)
2466{
2467 struct btrfs_device *dev;
2468 struct scrub_dev *sdev = NULL;
2469
2470 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2471 dev = btrfs_find_device(root, devid, NULL, NULL);
2472 if (dev)
2473 sdev = dev->scrub_device;
2474 if (sdev)
2475 memcpy(progress, &sdev->stat, sizeof(*progress));
2476 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2477
2478 return dev ? (sdev ? 0 : -ENOTCONN) : -ENODEV;
2479}