?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad...
[zen-stable.git] / fs / btrfs / scrub.c
blobc27bcb67f3304d806ab7e90cef8c3bcdef78b19c
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
29 /*
30 * This is only the first step towards a full-features scrub. It reads all
31 * extent and super block and verifies the checksums. In case a bad checksum
32 * is found or the extent cannot be read, good data will be written back if
33 * any can be found.
34 *
35 * Future enhancements:
36 * - In case an unrepairable extent is encountered, track which files are
37 * affected and report them
38 * - In case of a read error on files with nodatasum, map the file and read
39 * the extent to trigger a writeback of the good copy
40 * - track and record media errors, throw out bad devices
41 * - add a mode to also read unallocated space
42 */
43
44 struct scrub_bio;
45 struct scrub_page;
46 struct scrub_dev;
47 static void scrub_bio_end_io(struct bio *bio, int err);
48 static void scrub_checksum(struct btrfs_work *work);
49 static int scrub_checksum_data(struct scrub_dev *sdev,
50 struct scrub_page *spag, void *buffer);
51 static int scrub_checksum_tree_block(struct scrub_dev *sdev,
52 struct scrub_page *spag, u64 logical,
53 void *buffer);
54 static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer);
55 static int scrub_fixup_check(struct scrub_bio *sbio, int ix);
56 static void scrub_fixup_end_io(struct bio *bio, int err);
57 static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector,
58 struct page *page);
59 static void scrub_fixup(struct scrub_bio *sbio, int ix);
60
61 #define SCRUB_PAGES_PER_BIO 16 /* 64k per bio */
62 #define SCRUB_BIOS_PER_DEV 16 /* 1 MB per device in flight */
63
64 struct scrub_page {
65 u64 flags; /* extent flags */
66 u64 generation;
67 int mirror_num;
68 int have_csum;
69 u8 csum[BTRFS_CSUM_SIZE];
70 };
71
72 struct scrub_bio {
73 int index;
74 struct scrub_dev *sdev;
75 struct bio *bio;
76 int err;
77 u64 logical;
78 u64 physical;
79 struct scrub_page spag[SCRUB_PAGES_PER_BIO];
80 u64 count;
81 int next_free;
82 struct btrfs_work work;
83 };
84
85 struct scrub_dev {
86 struct scrub_bio *bios[SCRUB_BIOS_PER_DEV];
87 struct btrfs_device *dev;
88 int first_free;
89 int curr;
90 atomic_t in_flight;
91 atomic_t fixup_cnt;
92 spinlock_t list_lock;
93 wait_queue_head_t list_wait;
94 u16 csum_size;
95 struct list_head csum_list;
96 atomic_t cancel_req;
97 int readonly;
98 /*
99 * statistics
100 */
101 struct btrfs_scrub_progress stat;
102 spinlock_t stat_lock;
103 };
104
105 struct scrub_fixup_nodatasum {
106 struct scrub_dev *sdev;
107 u64 logical;
108 struct btrfs_root *root;
109 struct btrfs_work work;
110 int mirror_num;
111 };
112
113 struct scrub_warning {
114 struct btrfs_path *path;
115 u64 extent_item_size;
116 char *scratch_buf;
117 char *msg_buf;
118 const char *errstr;
119 sector_t sector;
120 u64 logical;
121 struct btrfs_device *dev;
122 int msg_bufsize;
123 int scratch_bufsize;
124 };
125
126 static void scrub_free_csums(struct scrub_dev *sdev)
127 {
128 while (!list_empty(&sdev->csum_list)) {
129 struct btrfs_ordered_sum *sum;
130 sum = list_first_entry(&sdev->csum_list,
131 struct btrfs_ordered_sum, list);
132 list_del(&sum->list);
133 kfree(sum);
134 }
135 }
136
137 static void scrub_free_bio(struct bio *bio)
138 {
139 int i;
140 struct page *last_page = NULL;
141
142 if (!bio)
143 return;
144
145 for (i = 0; i < bio->bi_vcnt; ++i) {
146 if (bio->bi_io_vec[i].bv_page == last_page)
147 continue;
148 last_page = bio->bi_io_vec[i].bv_page;
149 __free_page(last_page);
150 }
151 bio_put(bio);
152 }
153
154 static noinline_for_stack void scrub_free_dev(struct scrub_dev *sdev)
155 {
156 int i;
157
158 if (!sdev)
159 return;
160
161 for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
162 struct scrub_bio *sbio = sdev->bios[i];
163
164 if (!sbio)
165 break;
166
167 scrub_free_bio(sbio->bio);
168 kfree(sbio);
169 }
170
171 scrub_free_csums(sdev);
172 kfree(sdev);
173 }
174
175 static noinline_for_stack
176 struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev)
177 {
178 struct scrub_dev *sdev;
179 int i;
180 struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
181
182 sdev = kzalloc(sizeof(*sdev), GFP_NOFS);
183 if (!sdev)
184 goto nomem;
185 sdev->dev = dev;
186 for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
187 struct scrub_bio *sbio;
188
189 sbio = kzalloc(sizeof(*sbio), GFP_NOFS);
190 if (!sbio)
191 goto nomem;
192 sdev->bios[i] = sbio;
193
194 sbio->index = i;
195 sbio->sdev = sdev;
196 sbio->count = 0;
197 sbio->work.func = scrub_checksum;
198
199 if (i != SCRUB_BIOS_PER_DEV-1)
200 sdev->bios[i]->next_free = i + 1;
201 else
202 sdev->bios[i]->next_free = -1;
203 }
204 sdev->first_free = 0;
205 sdev->curr = -1;
206 atomic_set(&sdev->in_flight, 0);
207 atomic_set(&sdev->fixup_cnt, 0);
208 atomic_set(&sdev->cancel_req, 0);
209 sdev->csum_size = btrfs_super_csum_size(fs_info->super_copy);
210 INIT_LIST_HEAD(&sdev->csum_list);
211
212 spin_lock_init(&sdev->list_lock);
213 spin_lock_init(&sdev->stat_lock);
214 init_waitqueue_head(&sdev->list_wait);
215 return sdev;
216
217 nomem:
218 scrub_free_dev(sdev);
219 return ERR_PTR(-ENOMEM);
220 }
221
222 static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root, void *ctx)
223 {
224 u64 isize;
225 u32 nlink;
226 int ret;
227 int i;
228 struct extent_buffer *eb;
229 struct btrfs_inode_item *inode_item;
230 struct scrub_warning *swarn = ctx;
231 struct btrfs_fs_info *fs_info = swarn->dev->dev_root->fs_info;
232 struct inode_fs_paths *ipath = NULL;
233 struct btrfs_root *local_root;
234 struct btrfs_key root_key;
235
236 root_key.objectid = root;
237 root_key.type = BTRFS_ROOT_ITEM_KEY;
238 root_key.offset = (u64)-1;
239 local_root = btrfs_read_fs_root_no_name(fs_info, &root_key);
240 if (IS_ERR(local_root)) {
241 ret = PTR_ERR(local_root);
242 goto err;
243 }
244
245 ret = inode_item_info(inum, 0, local_root, swarn->path);
246 if (ret) {
247 btrfs_release_path(swarn->path);
248 goto err;
249 }
250
251 eb = swarn->path->nodes[0];
252 inode_item = btrfs_item_ptr(eb, swarn->path->slots[0],
253 struct btrfs_inode_item);
254 isize = btrfs_inode_size(eb, inode_item);
255 nlink = btrfs_inode_nlink(eb, inode_item);
256 btrfs_release_path(swarn->path);
257
258 ipath = init_ipath(4096, local_root, swarn->path);
259 if (IS_ERR(ipath)) {
260 ret = PTR_ERR(ipath);
261 ipath = NULL;
262 goto err;
263 }
264 ret = paths_from_inode(inum, ipath);
265
266 if (ret < 0)
267 goto err;
268
269 /*
270 * we deliberately ignore the bit ipath might have been too small to
271 * hold all of the paths here
272 */
273 for (i = 0; i < ipath->fspath->elem_cnt; ++i)
274 printk(KERN_WARNING "btrfs: %s at logical %llu on dev "
275 "%s, sector %llu, root %llu, inode %llu, offset %llu, "
276 "length %llu, links %u (path: %s)\n", swarn->errstr,
277 swarn->logical, swarn->dev->name,
278 (unsigned long long)swarn->sector, root, inum, offset,
279 min(isize - offset, (u64)PAGE_SIZE), nlink,
280 (char *)(unsigned long)ipath->fspath->val[i]);
281
282 free_ipath(ipath);
283 return 0;
284
285 err:
286 printk(KERN_WARNING "btrfs: %s at logical %llu on dev "
287 "%s, sector %llu, root %llu, inode %llu, offset %llu: path "
288 "resolving failed with ret=%d\n", swarn->errstr,
289 swarn->logical, swarn->dev->name,
290 (unsigned long long)swarn->sector, root, inum, offset, ret);
291
292 free_ipath(ipath);
293 return 0;
294 }
295
296 static void scrub_print_warning(const char *errstr, struct scrub_bio *sbio,
297 int ix)
298 {
299 struct btrfs_device *dev = sbio->sdev->dev;
300 struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
301 struct btrfs_path *path;
302 struct btrfs_key found_key;
303 struct extent_buffer *eb;
304 struct btrfs_extent_item *ei;
305 struct scrub_warning swarn;
306 u32 item_size;
307 int ret;
308 u64 ref_root;
309 u8 ref_level;
310 unsigned long ptr = 0;
311 const int bufsize = 4096;
312 u64 extent_offset;
313
314 path = btrfs_alloc_path();
315
316 swarn.scratch_buf = kmalloc(bufsize, GFP_NOFS);
317 swarn.msg_buf = kmalloc(bufsize, GFP_NOFS);
318 swarn.sector = (sbio->physical + ix * PAGE_SIZE) >> 9;
319 swarn.logical = sbio->logical + ix * PAGE_SIZE;
320 swarn.errstr = errstr;
321 swarn.dev = dev;
322 swarn.msg_bufsize = bufsize;
323 swarn.scratch_bufsize = bufsize;
324
325 if (!path || !swarn.scratch_buf || !swarn.msg_buf)
326 goto out;
327
328 ret = extent_from_logical(fs_info, swarn.logical, path, &found_key);
329 if (ret < 0)
330 goto out;
331
332 extent_offset = swarn.logical - found_key.objectid;
333 swarn.extent_item_size = found_key.offset;
334
335 eb = path->nodes[0];
336 ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
337 item_size = btrfs_item_size_nr(eb, path->slots[0]);
338
339 if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
340 do {
341 ret = tree_backref_for_extent(&ptr, eb, ei, item_size,
342 &ref_root, &ref_level);
343 printk(KERN_WARNING "%s at logical %llu on dev %s, "
344 "sector %llu: metadata %s (level %d) in tree "
345 "%llu\n", errstr, swarn.logical, dev->name,
346 (unsigned long long)swarn.sector,
347 ref_level ? "node" : "leaf",
348 ret < 0 ? -1 : ref_level,
349 ret < 0 ? -1 : ref_root);
350 } while (ret != 1);
351 } else {
352 swarn.path = path;
353 iterate_extent_inodes(fs_info, path, found_key.objectid,
354 extent_offset,
355 scrub_print_warning_inode, &swarn);
356 }
357
358 out:
359 btrfs_free_path(path);
360 kfree(swarn.scratch_buf);
361 kfree(swarn.msg_buf);
362 }
363
364 static int scrub_fixup_readpage(u64 inum, u64 offset, u64 root, void *ctx)
365 {
366 struct page *page = NULL;
367 unsigned long index;
368 struct scrub_fixup_nodatasum *fixup = ctx;
369 int ret;
370 int corrected = 0;
371 struct btrfs_key key;
372 struct inode *inode = NULL;
373 u64 end = offset + PAGE_SIZE - 1;
374 struct btrfs_root *local_root;
375
376 key.objectid = root;
377 key.type = BTRFS_ROOT_ITEM_KEY;
378 key.offset = (u64)-1;
379 local_root = btrfs_read_fs_root_no_name(fixup->root->fs_info, &key);
380 if (IS_ERR(local_root))
381 return PTR_ERR(local_root);
382
383 key.type = BTRFS_INODE_ITEM_KEY;
384 key.objectid = inum;
385 key.offset = 0;
386 inode = btrfs_iget(fixup->root->fs_info->sb, &key, local_root, NULL);
387 if (IS_ERR(inode))
388 return PTR_ERR(inode);
389
390 index = offset >> PAGE_CACHE_SHIFT;
391
392 page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
393 if (!page) {
394 ret = -ENOMEM;
395 goto out;
396 }
397
398 if (PageUptodate(page)) {
399 struct btrfs_mapping_tree *map_tree;
400 if (PageDirty(page)) {
401 /*
402 * we need to write the data to the defect sector. the
403 * data that was in that sector is not in memory,
404 * because the page was modified. we must not write the
405 * modified page to that sector.
406 *
407 * TODO: what could be done here: wait for the delalloc
408 * runner to write out that page (might involve
409 * COW) and see whether the sector is still
410 * referenced afterwards.
411 *
412 * For the meantime, we'll treat this error
413 * incorrectable, although there is a chance that a
414 * later scrub will find the bad sector again and that
415 * there's no dirty page in memory, then.
416 */
417 ret = -EIO;
418 goto out;
419 }
420 map_tree = &BTRFS_I(inode)->root->fs_info->mapping_tree;
421 ret = repair_io_failure(map_tree, offset, PAGE_SIZE,
422 fixup->logical, page,
423 fixup->mirror_num);
424 unlock_page(page);
425 corrected = !ret;
426 } else {
427 /*
428 * we need to get good data first. the general readpage path
429 * will call repair_io_failure for us, we just have to make
430 * sure we read the bad mirror.
431 */
432 ret = set_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
433 EXTENT_DAMAGED, GFP_NOFS);
434 if (ret) {
435 /* set_extent_bits should give proper error */
436 WARN_ON(ret > 0);
437 if (ret > 0)
438 ret = -EFAULT;
439 goto out;
440 }
441
442 ret = extent_read_full_page(&BTRFS_I(inode)->io_tree, page,
443 btrfs_get_extent,
444 fixup->mirror_num);
445 wait_on_page_locked(page);
446
447 corrected = !test_range_bit(&BTRFS_I(inode)->io_tree, offset,
448 end, EXTENT_DAMAGED, 0, NULL);
449 if (!corrected)
450 clear_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
451 EXTENT_DAMAGED, GFP_NOFS);
452 }
453
454 out:
455 if (page)
456 put_page(page);
457 if (inode)
458 iput(inode);
459
460 if (ret < 0)
461 return ret;
462
463 if (ret == 0 && corrected) {
464 /*
465 * we only need to call readpage for one of the inodes belonging
466 * to this extent. so make iterate_extent_inodes stop
467 */
468 return 1;
469 }
470
471 return -EIO;
472 }
473
474 static void scrub_fixup_nodatasum(struct btrfs_work *work)
475 {
476 int ret;
477 struct scrub_fixup_nodatasum *fixup;
478 struct scrub_dev *sdev;
479 struct btrfs_trans_handle *trans = NULL;
480 struct btrfs_fs_info *fs_info;
481 struct btrfs_path *path;
482 int uncorrectable = 0;
483
484 fixup = container_of(work, struct scrub_fixup_nodatasum, work);
485 sdev = fixup->sdev;
486 fs_info = fixup->root->fs_info;
487
488 path = btrfs_alloc_path();
489 if (!path) {
490 spin_lock(&sdev->stat_lock);
491 ++sdev->stat.malloc_errors;
492 spin_unlock(&sdev->stat_lock);
493 uncorrectable = 1;
494 goto out;
495 }
496
497 trans = btrfs_join_transaction(fixup->root);
498 if (IS_ERR(trans)) {
499 uncorrectable = 1;
500 goto out;
501 }
502
503 /*
504 * the idea is to trigger a regular read through the standard path. we
505 * read a page from the (failed) logical address by specifying the
506 * corresponding copynum of the failed sector. thus, that readpage is
507 * expected to fail.
508 * that is the point where on-the-fly error correction will kick in
509 * (once it's finished) and rewrite the failed sector if a good copy
510 * can be found.
511 */
512 ret = iterate_inodes_from_logical(fixup->logical, fixup->root->fs_info,
513 path, scrub_fixup_readpage,
514 fixup);
515 if (ret < 0) {
516 uncorrectable = 1;
517 goto out;
518 }
519 WARN_ON(ret != 1);
520
521 spin_lock(&sdev->stat_lock);
522 ++sdev->stat.corrected_errors;
523 spin_unlock(&sdev->stat_lock);
524
525 out:
526 if (trans && !IS_ERR(trans))
527 btrfs_end_transaction(trans, fixup->root);
528 if (uncorrectable) {
529 spin_lock(&sdev->stat_lock);
530 ++sdev->stat.uncorrectable_errors;
531 spin_unlock(&sdev->stat_lock);
532 printk_ratelimited(KERN_ERR "btrfs: unable to fixup "
533 "(nodatasum) error at logical %llu\n",
534 fixup->logical);
535 }
536
537 btrfs_free_path(path);
538 kfree(fixup);
539
540 /* see caller why we're pretending to be paused in the scrub counters */
541 mutex_lock(&fs_info->scrub_lock);
542 atomic_dec(&fs_info->scrubs_running);
543 atomic_dec(&fs_info->scrubs_paused);
544 mutex_unlock(&fs_info->scrub_lock);
545 atomic_dec(&sdev->fixup_cnt);
546 wake_up(&fs_info->scrub_pause_wait);
547 wake_up(&sdev->list_wait);
548 }
549
550 /*
551 * scrub_recheck_error gets called when either verification of the page
552 * failed or the bio failed to read, e.g. with EIO. In the latter case,
553 * recheck_error gets called for every page in the bio, even though only
554 * one may be bad
555 */
556 static int scrub_recheck_error(struct scrub_bio *sbio, int ix)
557 {
558 struct scrub_dev *sdev = sbio->sdev;
559 u64 sector = (sbio->physical + ix * PAGE_SIZE) >> 9;
560 static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
561 DEFAULT_RATELIMIT_BURST);
562
563 if (sbio->err) {
564 if (scrub_fixup_io(READ, sbio->sdev->dev->bdev, sector,
565 sbio->bio->bi_io_vec[ix].bv_page) == 0) {
566 if (scrub_fixup_check(sbio, ix) == 0)
567 return 0;
568 }
569 if (__ratelimit(&_rs))
570 scrub_print_warning("i/o error", sbio, ix);
571 } else {
572 if (__ratelimit(&_rs))
573 scrub_print_warning("checksum error", sbio, ix);
574 }
575
576 spin_lock(&sdev->stat_lock);
577 ++sdev->stat.read_errors;
578 spin_unlock(&sdev->stat_lock);
579
580 scrub_fixup(sbio, ix);
581 return 1;
582 }
583
584 static int scrub_fixup_check(struct scrub_bio *sbio, int ix)
585 {
586 int ret = 1;
587 struct page *page;
588 void *buffer;
589 u64 flags = sbio->spag[ix].flags;
590
591 page = sbio->bio->bi_io_vec[ix].bv_page;
592 buffer = kmap_atomic(page, KM_USER0);
593 if (flags & BTRFS_EXTENT_FLAG_DATA) {
594 ret = scrub_checksum_data(sbio->sdev,
595 sbio->spag + ix, buffer);
596 } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
597 ret = scrub_checksum_tree_block(sbio->sdev,
598 sbio->spag + ix,
599 sbio->logical + ix * PAGE_SIZE,
600 buffer);
601 } else {
602 WARN_ON(1);
603 }
604 kunmap_atomic(buffer, KM_USER0);
605
606 return ret;
607 }
608
609 static void scrub_fixup_end_io(struct bio *bio, int err)
610 {
611 complete((struct completion *)bio->bi_private);
612 }
613
614 static void scrub_fixup(struct scrub_bio *sbio, int ix)
615 {
616 struct scrub_dev *sdev = sbio->sdev;
617 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
618 struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
619 struct btrfs_bio *bbio = NULL;
620 struct scrub_fixup_nodatasum *fixup;
621 u64 logical = sbio->logical + ix * PAGE_SIZE;
622 u64 length;
623 int i;
624 int ret;
625 DECLARE_COMPLETION_ONSTACK(complete);
626
627 if ((sbio->spag[ix].flags & BTRFS_EXTENT_FLAG_DATA) &&
628 (sbio->spag[ix].have_csum == 0)) {
629 fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
630 if (!fixup)
631 goto uncorrectable;
632 fixup->sdev = sdev;
633 fixup->logical = logical;
634 fixup->root = fs_info->extent_root;
635 fixup->mirror_num = sbio->spag[ix].mirror_num;
636 /*
637 * increment scrubs_running to prevent cancel requests from
638 * completing as long as a fixup worker is running. we must also
639 * increment scrubs_paused to prevent deadlocking on pause
640 * requests used for transactions commits (as the worker uses a
641 * transaction context). it is safe to regard the fixup worker
642 * as paused for all matters practical. effectively, we only
643 * avoid cancellation requests from completing.
644 */
645 mutex_lock(&fs_info->scrub_lock);
646 atomic_inc(&fs_info->scrubs_running);
647 atomic_inc(&fs_info->scrubs_paused);
648 mutex_unlock(&fs_info->scrub_lock);
649 atomic_inc(&sdev->fixup_cnt);
650 fixup->work.func = scrub_fixup_nodatasum;
651 btrfs_queue_worker(&fs_info->scrub_workers, &fixup->work);
652 return;
653 }
654
655 length = PAGE_SIZE;
656 ret = btrfs_map_block(map_tree, REQ_WRITE, logical, &length,
657 &bbio, 0);
658 if (ret || !bbio || length < PAGE_SIZE) {
659 printk(KERN_ERR
660 "scrub_fixup: btrfs_map_block failed us for %llu\n",
661 (unsigned long long)logical);
662 WARN_ON(1);
663 kfree(bbio);
664 return;
665 }
666
667 if (bbio->num_stripes == 1)
668 /* there aren't any replicas */
669 goto uncorrectable;
670
671 /*
672 * first find a good copy
673 */
674 for (i = 0; i < bbio->num_stripes; ++i) {
675 if (i + 1 == sbio->spag[ix].mirror_num)
676 continue;
677
678 if (scrub_fixup_io(READ, bbio->stripes[i].dev->bdev,
679 bbio->stripes[i].physical >> 9,
680 sbio->bio->bi_io_vec[ix].bv_page)) {
681 /* I/O-error, this is not a good copy */
682 continue;
683 }
684
685 if (scrub_fixup_check(sbio, ix) == 0)
686 break;
687 }
688 if (i == bbio->num_stripes)
689 goto uncorrectable;
690
691 if (!sdev->readonly) {
692 /*
693 * bi_io_vec[ix].bv_page now contains good data, write it back
694 */
695 if (scrub_fixup_io(WRITE, sdev->dev->bdev,
696 (sbio->physical + ix * PAGE_SIZE) >> 9,
697 sbio->bio->bi_io_vec[ix].bv_page)) {
698 /* I/O-error, writeback failed, give up */
699 goto uncorrectable;
700 }
701 }
702
703 kfree(bbio);
704 spin_lock(&sdev->stat_lock);
705 ++sdev->stat.corrected_errors;
706 spin_unlock(&sdev->stat_lock);
707
708 printk_ratelimited(KERN_ERR "btrfs: fixed up error at logical %llu\n",
709 (unsigned long long)logical);
710 return;
711
712 uncorrectable:
713 kfree(bbio);
714 spin_lock(&sdev->stat_lock);
715 ++sdev->stat.uncorrectable_errors;
716 spin_unlock(&sdev->stat_lock);
717
718 printk_ratelimited(KERN_ERR "btrfs: unable to fixup (regular) error at "
719 "logical %llu\n", (unsigned long long)logical);
720 }
721
722 static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector,
723 struct page *page)
724 {
725 struct bio *bio = NULL;
726 int ret;
727 DECLARE_COMPLETION_ONSTACK(complete);
728
729 bio = bio_alloc(GFP_NOFS, 1);
730 bio->bi_bdev = bdev;
731 bio->bi_sector = sector;
732 bio_add_page(bio, page, PAGE_SIZE, 0);
733 bio->bi_end_io = scrub_fixup_end_io;
734 bio->bi_private = &complete;
735 submit_bio(rw, bio);
736
737 /* this will also unplug the queue */
738 wait_for_completion(&complete);
739
740 ret = !test_bit(BIO_UPTODATE, &bio->bi_flags);
741 bio_put(bio);
742 return ret;
743 }
744
745 static void scrub_bio_end_io(struct bio *bio, int err)
746 {
747 struct scrub_bio *sbio = bio->bi_private;
748 struct scrub_dev *sdev = sbio->sdev;
749 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
750
751 sbio->err = err;
752 sbio->bio = bio;
753
754 btrfs_queue_worker(&fs_info->scrub_workers, &sbio->work);
755 }
756
757 static void scrub_checksum(struct btrfs_work *work)
758 {
759 struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
760 struct scrub_dev *sdev = sbio->sdev;
761 struct page *page;
762 void *buffer;
763 int i;
764 u64 flags;
765 u64 logical;
766 int ret;
767
768 if (sbio->err) {
769 ret = 0;
770 for (i = 0; i < sbio->count; ++i)
771 ret |= scrub_recheck_error(sbio, i);
772 if (!ret) {
773 spin_lock(&sdev->stat_lock);
774 ++sdev->stat.unverified_errors;
775 spin_unlock(&sdev->stat_lock);
776 }
777
778 sbio->bio->bi_flags &= ~(BIO_POOL_MASK - 1);
779 sbio->bio->bi_flags |= 1 << BIO_UPTODATE;
780 sbio->bio->bi_phys_segments = 0;
781 sbio->bio->bi_idx = 0;
782
783 for (i = 0; i < sbio->count; i++) {
784 struct bio_vec *bi;
785 bi = &sbio->bio->bi_io_vec[i];
786 bi->bv_offset = 0;
787 bi->bv_len = PAGE_SIZE;
788 }
789 goto out;
790 }
791 for (i = 0; i < sbio->count; ++i) {
792 page = sbio->bio->bi_io_vec[i].bv_page;
793 buffer = kmap_atomic(page, KM_USER0);
794 flags = sbio->spag[i].flags;
795 logical = sbio->logical + i * PAGE_SIZE;
796 ret = 0;
797 if (flags & BTRFS_EXTENT_FLAG_DATA) {
798 ret = scrub_checksum_data(sdev, sbio->spag + i, buffer);
799 } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
800 ret = scrub_checksum_tree_block(sdev, sbio->spag + i,
801 logical, buffer);
802 } else if (flags & BTRFS_EXTENT_FLAG_SUPER) {
803 BUG_ON(i);
804 (void)scrub_checksum_super(sbio, buffer);
805 } else {
806 WARN_ON(1);
807 }
808 kunmap_atomic(buffer, KM_USER0);
809 if (ret) {
810 ret = scrub_recheck_error(sbio, i);
811 if (!ret) {
812 spin_lock(&sdev->stat_lock);
813 ++sdev->stat.unverified_errors;
814 spin_unlock(&sdev->stat_lock);
815 }
816 }
817 }
818
819 out:
820 scrub_free_bio(sbio->bio);
821 sbio->bio = NULL;
822 spin_lock(&sdev->list_lock);
823 sbio->next_free = sdev->first_free;
824 sdev->first_free = sbio->index;
825 spin_unlock(&sdev->list_lock);
826 atomic_dec(&sdev->in_flight);
827 wake_up(&sdev->list_wait);
828 }
829
830 static int scrub_checksum_data(struct scrub_dev *sdev,
831 struct scrub_page *spag, void *buffer)
832 {
833 u8 csum[BTRFS_CSUM_SIZE];
834 u32 crc = ~(u32)0;
835 int fail = 0;
836 struct btrfs_root *root = sdev->dev->dev_root;
837
838 if (!spag->have_csum)
839 return 0;
840
841 crc = btrfs_csum_data(root, buffer, crc, PAGE_SIZE);
842 btrfs_csum_final(crc, csum);
843 if (memcmp(csum, spag->csum, sdev->csum_size))
844 fail = 1;
845
846 spin_lock(&sdev->stat_lock);
847 ++sdev->stat.data_extents_scrubbed;
848 sdev->stat.data_bytes_scrubbed += PAGE_SIZE;
849 if (fail)
850 ++sdev->stat.csum_errors;
851 spin_unlock(&sdev->stat_lock);
852
853 return fail;
854 }
855
856 static int scrub_checksum_tree_block(struct scrub_dev *sdev,
857 struct scrub_page *spag, u64 logical,
858 void *buffer)
859 {
860 struct btrfs_header *h;
861 struct btrfs_root *root = sdev->dev->dev_root;
862 struct btrfs_fs_info *fs_info = root->fs_info;
863 u8 csum[BTRFS_CSUM_SIZE];
864 u32 crc = ~(u32)0;
865 int fail = 0;
866 int crc_fail = 0;
867
868 /*
869 * we don't use the getter functions here, as we
870 * a) don't have an extent buffer and
871 * b) the page is already kmapped
872 */
873 h = (struct btrfs_header *)buffer;
874
875 if (logical != le64_to_cpu(h->bytenr))
876 ++fail;
877
878 if (spag->generation != le64_to_cpu(h->generation))
879 ++fail;
880
881 if (memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
882 ++fail;
883
884 if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
885 BTRFS_UUID_SIZE))
886 ++fail;
887
888 crc = btrfs_csum_data(root, buffer + BTRFS_CSUM_SIZE, crc,
889 PAGE_SIZE - BTRFS_CSUM_SIZE);
890 btrfs_csum_final(crc, csum);
891 if (memcmp(csum, h->csum, sdev->csum_size))
892 ++crc_fail;
893
894 spin_lock(&sdev->stat_lock);
895 ++sdev->stat.tree_extents_scrubbed;
896 sdev->stat.tree_bytes_scrubbed += PAGE_SIZE;
897 if (crc_fail)
898 ++sdev->stat.csum_errors;
899 if (fail)
900 ++sdev->stat.verify_errors;
901 spin_unlock(&sdev->stat_lock);
902
903 return fail || crc_fail;
904 }
905
906 static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer)
907 {
908 struct btrfs_super_block *s;
909 u64 logical;
910 struct scrub_dev *sdev = sbio->sdev;
911 struct btrfs_root *root = sdev->dev->dev_root;
912 struct btrfs_fs_info *fs_info = root->fs_info;
913 u8 csum[BTRFS_CSUM_SIZE];
914 u32 crc = ~(u32)0;
915 int fail = 0;
916
917 s = (struct btrfs_super_block *)buffer;
918 logical = sbio->logical;
919
920 if (logical != le64_to_cpu(s->bytenr))
921 ++fail;
922
923 if (sbio->spag[0].generation != le64_to_cpu(s->generation))
924 ++fail;
925
926 if (memcmp(s->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
927 ++fail;
928
929 crc = btrfs_csum_data(root, buffer + BTRFS_CSUM_SIZE, crc,
930 PAGE_SIZE - BTRFS_CSUM_SIZE);
931 btrfs_csum_final(crc, csum);
932 if (memcmp(csum, s->csum, sbio->sdev->csum_size))
933 ++fail;
934
935 if (fail) {
936 /*
937 * if we find an error in a super block, we just report it.
938 * They will get written with the next transaction commit
939 * anyway
940 */
941 spin_lock(&sdev->stat_lock);
942 ++sdev->stat.super_errors;
943 spin_unlock(&sdev->stat_lock);
944 }
945
946 return fail;
947 }
948
949 static int scrub_submit(struct scrub_dev *sdev)
950 {
951 struct scrub_bio *sbio;
952
953 if (sdev->curr == -1)
954 return 0;
955
956 sbio = sdev->bios[sdev->curr];
957 sbio->err = 0;
958 sdev->curr = -1;
959 atomic_inc(&sdev->in_flight);
960
961 submit_bio(READ, sbio->bio);
962
963 return 0;
964 }
965
966 static int scrub_page(struct scrub_dev *sdev, u64 logical, u64 len,
967 u64 physical, u64 flags, u64 gen, int mirror_num,
968 u8 *csum, int force)
969 {
970 struct scrub_bio *sbio;
971 struct page *page;
972 int ret;
973
974 again:
975 /*
976 * grab a fresh bio or wait for one to become available
977 */
978 while (sdev->curr == -1) {
979 spin_lock(&sdev->list_lock);
980 sdev->curr = sdev->first_free;
981 if (sdev->curr != -1) {
982 sdev->first_free = sdev->bios[sdev->curr]->next_free;
983 sdev->bios[sdev->curr]->next_free = -1;
984 sdev->bios[sdev->curr]->count = 0;
985 spin_unlock(&sdev->list_lock);
986 } else {
987 spin_unlock(&sdev->list_lock);
988 wait_event(sdev->list_wait, sdev->first_free != -1);
989 }
990 }
991 sbio = sdev->bios[sdev->curr];
992 if (sbio->count == 0) {
993 struct bio *bio;
994
995 sbio->physical = physical;
996 sbio->logical = logical;
997 bio = bio_alloc(GFP_NOFS, SCRUB_PAGES_PER_BIO);
998 if (!bio)
999 return -ENOMEM;
1000
1001 bio->bi_private = sbio;
1002 bio->bi_end_io = scrub_bio_end_io;
1003 bio->bi_bdev = sdev->dev->bdev;
1004 bio->bi_sector = sbio->physical >> 9;
1005 sbio->err = 0;
1006 sbio->bio = bio;
1007 } else if (sbio->physical + sbio->count * PAGE_SIZE != physical ||
1008 sbio->logical + sbio->count * PAGE_SIZE != logical) {
1009 ret = scrub_submit(sdev);
1010 if (ret)
1011 return ret;
1012 goto again;
1013 }
1014 sbio->spag[sbio->count].flags = flags;
1015 sbio->spag[sbio->count].generation = gen;
1016 sbio->spag[sbio->count].have_csum = 0;
1017 sbio->spag[sbio->count].mirror_num = mirror_num;
1018
1019 page = alloc_page(GFP_NOFS);
1020 if (!page)
1021 return -ENOMEM;
1022
1023 ret = bio_add_page(sbio->bio, page, PAGE_SIZE, 0);
1024 if (!ret) {
1025 __free_page(page);
1026 ret = scrub_submit(sdev);
1027 if (ret)
1028 return ret;
1029 goto again;
1030 }
1031
1032 if (csum) {
1033 sbio->spag[sbio->count].have_csum = 1;
1034 memcpy(sbio->spag[sbio->count].csum, csum, sdev->csum_size);
1035 }
1036 ++sbio->count;
1037 if (sbio->count == SCRUB_PAGES_PER_BIO || force) {
1038 int ret;
1039
1040 ret = scrub_submit(sdev);
1041 if (ret)
1042 return ret;
1043 }
1044
1045 return 0;
1046 }
1047
1048 static int scrub_find_csum(struct scrub_dev *sdev, u64 logical, u64 len,
1049 u8 *csum)
1050 {
1051 struct btrfs_ordered_sum *sum = NULL;
1052 int ret = 0;
1053 unsigned long i;
1054 unsigned long num_sectors;
1055 u32 sectorsize = sdev->dev->dev_root->sectorsize;
1056
1057 while (!list_empty(&sdev->csum_list)) {
1058 sum = list_first_entry(&sdev->csum_list,
1059 struct btrfs_ordered_sum, list);
1060 if (sum->bytenr > logical)
1061 return 0;
1062 if (sum->bytenr + sum->len > logical)
1063 break;
1064
1065 ++sdev->stat.csum_discards;
1066 list_del(&sum->list);
1067 kfree(sum);
1068 sum = NULL;
1069 }
1070 if (!sum)
1071 return 0;
1072
1073 num_sectors = sum->len / sectorsize;
1074 for (i = 0; i < num_sectors; ++i) {
1075 if (sum->sums[i].bytenr == logical) {
1076 memcpy(csum, &sum->sums[i].sum, sdev->csum_size);
1077 ret = 1;
1078 break;
1079 }
1080 }
1081 if (ret && i == num_sectors - 1) {
1082 list_del(&sum->list);
1083 kfree(sum);
1084 }
1085 return ret;
1086 }
1087
1088 /* scrub extent tries to collect up to 64 kB for each bio */
1089 static int scrub_extent(struct scrub_dev *sdev, u64 logical, u64 len,
1090 u64 physical, u64 flags, u64 gen, int mirror_num)
1091 {
1092 int ret;
1093 u8 csum[BTRFS_CSUM_SIZE];
1094
1095 while (len) {
1096 u64 l = min_t(u64, len, PAGE_SIZE);
1097 int have_csum = 0;
1098
1099 if (flags & BTRFS_EXTENT_FLAG_DATA) {
1100 /* push csums to sbio */
1101 have_csum = scrub_find_csum(sdev, logical, l, csum);
1102 if (have_csum == 0)
1103 ++sdev->stat.no_csum;
1104 }
1105 ret = scrub_page(sdev, logical, l, physical, flags, gen,
1106 mirror_num, have_csum ? csum : NULL, 0);
1107 if (ret)
1108 return ret;
1109 len -= l;
1110 logical += l;
1111 physical += l;
1112 }
1113 return 0;
1114 }
1115
1116 static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev,
1117 struct map_lookup *map, int num, u64 base, u64 length)
1118 {
1119 struct btrfs_path *path;
1120 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
1121 struct btrfs_root *root = fs_info->extent_root;
1122 struct btrfs_root *csum_root = fs_info->csum_root;
1123 struct btrfs_extent_item *extent;
1124 struct blk_plug plug;
1125 u64 flags;
1126 int ret;
1127 int slot;
1128 int i;
1129 u64 nstripes;
1130 struct extent_buffer *l;
1131 struct btrfs_key key;
1132 u64 physical;
1133 u64 logical;
1134 u64 generation;
1135 int mirror_num;
1136 struct reada_control *reada1;
1137 struct reada_control *reada2;
1138 struct btrfs_key key_start;
1139 struct btrfs_key key_end;
1140
1141 u64 increment = map->stripe_len;
1142 u64 offset;
1143
1144 nstripes = length;
1145 offset = 0;
1146 do_div(nstripes, map->stripe_len);
1147 if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
1148 offset = map->stripe_len * num;
1149 increment = map->stripe_len * map->num_stripes;
1150 mirror_num = 1;
1151 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1152 int factor = map->num_stripes / map->sub_stripes;
1153 offset = map->stripe_len * (num / map->sub_stripes);
1154 increment = map->stripe_len * factor;
1155 mirror_num = num % map->sub_stripes + 1;
1156 } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
1157 increment = map->stripe_len;
1158 mirror_num = num % map->num_stripes + 1;
1159 } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
1160 increment = map->stripe_len;
1161 mirror_num = num % map->num_stripes + 1;
1162 } else {
1163 increment = map->stripe_len;
1164 mirror_num = 1;
1165 }
1166
1167 path = btrfs_alloc_path();
1168 if (!path)
1169 return -ENOMEM;
1170
1171 path->search_commit_root = 1;
1172 path->skip_locking = 1;
1173
1174 /*
1175 * trigger the readahead for extent tree csum tree and wait for
1176 * completion. During readahead, the scrub is officially paused
1177 * to not hold off transaction commits
1178 */
1179 logical = base + offset;
1180
1181 wait_event(sdev->list_wait,
1182 atomic_read(&sdev->in_flight) == 0);
1183 atomic_inc(&fs_info->scrubs_paused);
1184 wake_up(&fs_info->scrub_pause_wait);
1185
1186 /* FIXME it might be better to start readahead at commit root */
1187 key_start.objectid = logical;
1188 key_start.type = BTRFS_EXTENT_ITEM_KEY;
1189 key_start.offset = (u64)0;
1190 key_end.objectid = base + offset + nstripes * increment;
1191 key_end.type = BTRFS_EXTENT_ITEM_KEY;
1192 key_end.offset = (u64)0;
1193 reada1 = btrfs_reada_add(root, &key_start, &key_end);
1194
1195 key_start.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
1196 key_start.type = BTRFS_EXTENT_CSUM_KEY;
1197 key_start.offset = logical;
1198 key_end.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
1199 key_end.type = BTRFS_EXTENT_CSUM_KEY;
1200 key_end.offset = base + offset + nstripes * increment;
1201 reada2 = btrfs_reada_add(csum_root, &key_start, &key_end);
1202
1203 if (!IS_ERR(reada1))
1204 btrfs_reada_wait(reada1);
1205 if (!IS_ERR(reada2))
1206 btrfs_reada_wait(reada2);
1207
1208 mutex_lock(&fs_info->scrub_lock);
1209 while (atomic_read(&fs_info->scrub_pause_req)) {
1210 mutex_unlock(&fs_info->scrub_lock);
1211 wait_event(fs_info->scrub_pause_wait,
1212 atomic_read(&fs_info->scrub_pause_req) == 0);
1213 mutex_lock(&fs_info->scrub_lock);
1214 }
1215 atomic_dec(&fs_info->scrubs_paused);
1216 mutex_unlock(&fs_info->scrub_lock);
1217 wake_up(&fs_info->scrub_pause_wait);
1218
1219 /*
1220 * collect all data csums for the stripe to avoid seeking during
1221 * the scrub. This might currently (crc32) end up to be about 1MB
1222 */
1223 blk_start_plug(&plug);
1224
1225 /*
1226 * now find all extents for each stripe and scrub them
1227 */
1228 logical = base + offset;
1229 physical = map->stripes[num].physical;
1230 ret = 0;
1231 for (i = 0; i < nstripes; ++i) {
1232 /*
1233 * canceled?
1234 */
1235 if (atomic_read(&fs_info->scrub_cancel_req) ||
1236 atomic_read(&sdev->cancel_req)) {
1237 ret = -ECANCELED;
1238 goto out;
1239 }
1240 /*
1241 * check to see if we have to pause
1242 */
1243 if (atomic_read(&fs_info->scrub_pause_req)) {
1244 /* push queued extents */
1245 scrub_submit(sdev);
1246 wait_event(sdev->list_wait,
1247 atomic_read(&sdev->in_flight) == 0);
1248 atomic_inc(&fs_info->scrubs_paused);
1249 wake_up(&fs_info->scrub_pause_wait);
1250 mutex_lock(&fs_info->scrub_lock);
1251 while (atomic_read(&fs_info->scrub_pause_req)) {
1252 mutex_unlock(&fs_info->scrub_lock);
1253 wait_event(fs_info->scrub_pause_wait,
1254 atomic_read(&fs_info->scrub_pause_req) == 0);
1255 mutex_lock(&fs_info->scrub_lock);
1256 }
1257 atomic_dec(&fs_info->scrubs_paused);
1258 mutex_unlock(&fs_info->scrub_lock);
1259 wake_up(&fs_info->scrub_pause_wait);
1260 }
1261
1262 ret = btrfs_lookup_csums_range(csum_root, logical,
1263 logical + map->stripe_len - 1,
1264 &sdev->csum_list, 1);
1265 if (ret)
1266 goto out;
1267
1268 key.objectid = logical;
1269 key.type = BTRFS_EXTENT_ITEM_KEY;
1270 key.offset = (u64)0;
1271
1272 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1273 if (ret < 0)
1274 goto out;
1275 if (ret > 0) {
1276 ret = btrfs_previous_item(root, path, 0,
1277 BTRFS_EXTENT_ITEM_KEY);
1278 if (ret < 0)
1279 goto out;
1280 if (ret > 0) {
1281 /* there's no smaller item, so stick with the
1282 * larger one */
1283 btrfs_release_path(path);
1284 ret = btrfs_search_slot(NULL, root, &key,
1285 path, 0, 0);
1286 if (ret < 0)
1287 goto out;
1288 }
1289 }
1290
1291 while (1) {
1292 l = path->nodes[0];
1293 slot = path->slots[0];
1294 if (slot >= btrfs_header_nritems(l)) {
1295 ret = btrfs_next_leaf(root, path);
1296 if (ret == 0)
1297 continue;
1298 if (ret < 0)
1299 goto out;
1300
1301 break;
1302 }
1303 btrfs_item_key_to_cpu(l, &key, slot);
1304
1305 if (key.objectid + key.offset <= logical)
1306 goto next;
1307
1308 if (key.objectid >= logical + map->stripe_len)
1309 break;
1310
1311 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY)
1312 goto next;
1313
1314 extent = btrfs_item_ptr(l, slot,
1315 struct btrfs_extent_item);
1316 flags = btrfs_extent_flags(l, extent);
1317 generation = btrfs_extent_generation(l, extent);
1318
1319 if (key.objectid < logical &&
1320 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) {
1321 printk(KERN_ERR
1322 "btrfs scrub: tree block %llu spanning "
1323 "stripes, ignored. logical=%llu\n",
1324 (unsigned long long)key.objectid,
1325 (unsigned long long)logical);
1326 goto next;
1327 }
1328
1329 /*
1330 * trim extent to this stripe
1331 */
1332 if (key.objectid < logical) {
1333 key.offset -= logical - key.objectid;
1334 key.objectid = logical;
1335 }
1336 if (key.objectid + key.offset >
1337 logical + map->stripe_len) {
1338 key.offset = logical + map->stripe_len -
1339 key.objectid;
1340 }
1341
1342 ret = scrub_extent(sdev, key.objectid, key.offset,
1343 key.objectid - logical + physical,
1344 flags, generation, mirror_num);
1345 if (ret)
1346 goto out;
1347
1348 next:
1349 path->slots[0]++;
1350 }
1351 btrfs_release_path(path);
1352 logical += increment;
1353 physical += map->stripe_len;
1354 spin_lock(&sdev->stat_lock);
1355 sdev->stat.last_physical = physical;
1356 spin_unlock(&sdev->stat_lock);
1357 }
1358 /* push queued extents */
1359 scrub_submit(sdev);
1360
1361 out:
1362 blk_finish_plug(&plug);
1363 btrfs_free_path(path);
1364 return ret < 0 ? ret : 0;
1365 }
1366
1367 static noinline_for_stack int scrub_chunk(struct scrub_dev *sdev,
1368 u64 chunk_tree, u64 chunk_objectid, u64 chunk_offset, u64 length)
1369 {
1370 struct btrfs_mapping_tree *map_tree =
1371 &sdev->dev->dev_root->fs_info->mapping_tree;
1372 struct map_lookup *map;
1373 struct extent_map *em;
1374 int i;
1375 int ret = -EINVAL;
1376
1377 read_lock(&map_tree->map_tree.lock);
1378 em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
1379 read_unlock(&map_tree->map_tree.lock);
1380
1381 if (!em)
1382 return -EINVAL;
1383
1384 map = (struct map_lookup *)em->bdev;
1385 if (em->start != chunk_offset)
1386 goto out;
1387
1388 if (em->len < length)
1389 goto out;
1390
1391 for (i = 0; i < map->num_stripes; ++i) {
1392 if (map->stripes[i].dev == sdev->dev) {
1393 ret = scrub_stripe(sdev, map, i, chunk_offset, length);
1394 if (ret)
1395 goto out;
1396 }
1397 }
1398 out:
1399 free_extent_map(em);
1400
1401 return ret;
1402 }
1403
1404 static noinline_for_stack
1405 int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end)
1406 {
1407 struct btrfs_dev_extent *dev_extent = NULL;
1408 struct btrfs_path *path;
1409 struct btrfs_root *root = sdev->dev->dev_root;
1410 struct btrfs_fs_info *fs_info = root->fs_info;
1411 u64 length;
1412 u64 chunk_tree;
1413 u64 chunk_objectid;
1414 u64 chunk_offset;
1415 int ret;
1416 int slot;
1417 struct extent_buffer *l;
1418 struct btrfs_key key;
1419 struct btrfs_key found_key;
1420 struct btrfs_block_group_cache *cache;
1421
1422 path = btrfs_alloc_path();
1423 if (!path)
1424 return -ENOMEM;
1425
1426 path->reada = 2;
1427 path->search_commit_root = 1;
1428 path->skip_locking = 1;
1429
1430 key.objectid = sdev->dev->devid;
1431 key.offset = 0ull;
1432 key.type = BTRFS_DEV_EXTENT_KEY;
1433
1434
1435 while (1) {
1436 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1437 if (ret < 0)
1438 break;
1439 if (ret > 0) {
1440 if (path->slots[0] >=
1441 btrfs_header_nritems(path->nodes[0])) {
1442 ret = btrfs_next_leaf(root, path);
1443 if (ret)
1444 break;
1445 }
1446 }
1447
1448 l = path->nodes[0];
1449 slot = path->slots[0];
1450
1451 btrfs_item_key_to_cpu(l, &found_key, slot);
1452
1453 if (found_key.objectid != sdev->dev->devid)
1454 break;
1455
1456 if (btrfs_key_type(&found_key) != BTRFS_DEV_EXTENT_KEY)
1457 break;
1458
1459 if (found_key.offset >= end)
1460 break;
1461
1462 if (found_key.offset < key.offset)
1463 break;
1464
1465 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1466 length = btrfs_dev_extent_length(l, dev_extent);
1467
1468 if (found_key.offset + length <= start) {
1469 key.offset = found_key.offset + length;
1470 btrfs_release_path(path);
1471 continue;
1472 }
1473
1474 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
1475 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
1476 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
1477
1478 /*
1479 * get a reference on the corresponding block group to prevent
1480 * the chunk from going away while we scrub it
1481 */
1482 cache = btrfs_lookup_block_group(fs_info, chunk_offset);
1483 if (!cache) {
1484 ret = -ENOENT;
1485 break;
1486 }
1487 ret = scrub_chunk(sdev, chunk_tree, chunk_objectid,
1488 chunk_offset, length);
1489 btrfs_put_block_group(cache);
1490 if (ret)
1491 break;
1492
1493 key.offset = found_key.offset + length;
1494 btrfs_release_path(path);
1495 }
1496
1497 btrfs_free_path(path);
1498
1499 /*
1500 * ret can still be 1 from search_slot or next_leaf,
1501 * that's not an error
1502 */
1503 return ret < 0 ? ret : 0;
1504 }
1505
1506 static noinline_for_stack int scrub_supers(struct scrub_dev *sdev)
1507 {
1508 int i;
1509 u64 bytenr;
1510 u64 gen;
1511 int ret;
1512 struct btrfs_device *device = sdev->dev;
1513 struct btrfs_root *root = device->dev_root;
1514
1515 gen = root->fs_info->last_trans_committed;
1516
1517 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
1518 bytenr = btrfs_sb_offset(i);
1519 if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
1520 break;
1521
1522 ret = scrub_page(sdev, bytenr, PAGE_SIZE, bytenr,
1523 BTRFS_EXTENT_FLAG_SUPER, gen, i, NULL, 1);
1524 if (ret)
1525 return ret;
1526 }
1527 wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
1528
1529 return 0;
1530 }
1531
1532 /*
1533 * get a reference count on fs_info->scrub_workers. start worker if necessary
1534 */
1535 static noinline_for_stack int scrub_workers_get(struct btrfs_root *root)
1536 {
1537 struct btrfs_fs_info *fs_info = root->fs_info;
1538
1539 mutex_lock(&fs_info->scrub_lock);
1540 if (fs_info->scrub_workers_refcnt == 0) {
1541 btrfs_init_workers(&fs_info->scrub_workers, "scrub",
1542 fs_info->thread_pool_size, &fs_info->generic_worker);
1543 fs_info->scrub_workers.idle_thresh = 4;
1544 btrfs_start_workers(&fs_info->scrub_workers, 1);
1545 }
1546 ++fs_info->scrub_workers_refcnt;
1547 mutex_unlock(&fs_info->scrub_lock);
1548
1549 return 0;
1550 }
1551
1552 static noinline_for_stack void scrub_workers_put(struct btrfs_root *root)
1553 {
1554 struct btrfs_fs_info *fs_info = root->fs_info;
1555
1556 mutex_lock(&fs_info->scrub_lock);
1557 if (--fs_info->scrub_workers_refcnt == 0)
1558 btrfs_stop_workers(&fs_info->scrub_workers);
1559 WARN_ON(fs_info->scrub_workers_refcnt < 0);
1560 mutex_unlock(&fs_info->scrub_lock);
1561 }
1562
1563
1564 int btrfs_scrub_dev(struct btrfs_root *root, u64 devid, u64 start, u64 end,
1565 struct btrfs_scrub_progress *progress, int readonly)
1566 {
1567 struct scrub_dev *sdev;
1568 struct btrfs_fs_info *fs_info = root->fs_info;
1569 int ret;
1570 struct btrfs_device *dev;
1571
1572 if (btrfs_fs_closing(root->fs_info))
1573 return -EINVAL;
1574
1575 /*
1576 * check some assumptions
1577 */
1578 if (root->sectorsize != PAGE_SIZE ||
1579 root->sectorsize != root->leafsize ||
1580 root->sectorsize != root->nodesize) {
1581 printk(KERN_ERR "btrfs_scrub: size assumptions fail\n");
1582 return -EINVAL;
1583 }
1584
1585 ret = scrub_workers_get(root);
1586 if (ret)
1587 return ret;
1588
1589 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1590 dev = btrfs_find_device(root, devid, NULL, NULL);
1591 if (!dev || dev->missing) {
1592 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1593 scrub_workers_put(root);
1594 return -ENODEV;
1595 }
1596 mutex_lock(&fs_info->scrub_lock);
1597
1598 if (!dev->in_fs_metadata) {
1599 mutex_unlock(&fs_info->scrub_lock);
1600 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1601 scrub_workers_put(root);
1602 return -ENODEV;
1603 }
1604
1605 if (dev->scrub_device) {
1606 mutex_unlock(&fs_info->scrub_lock);
1607 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1608 scrub_workers_put(root);
1609 return -EINPROGRESS;
1610 }
1611 sdev = scrub_setup_dev(dev);
1612 if (IS_ERR(sdev)) {
1613 mutex_unlock(&fs_info->scrub_lock);
1614 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1615 scrub_workers_put(root);
1616 return PTR_ERR(sdev);
1617 }
1618 sdev->readonly = readonly;
1619 dev->scrub_device = sdev;
1620
1621 atomic_inc(&fs_info->scrubs_running);
1622 mutex_unlock(&fs_info->scrub_lock);
1623 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1624
1625 down_read(&fs_info->scrub_super_lock);
1626 ret = scrub_supers(sdev);
1627 up_read(&fs_info->scrub_super_lock);
1628
1629 if (!ret)
1630 ret = scrub_enumerate_chunks(sdev, start, end);
1631
1632 wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
1633 atomic_dec(&fs_info->scrubs_running);
1634 wake_up(&fs_info->scrub_pause_wait);
1635
1636 wait_event(sdev->list_wait, atomic_read(&sdev->fixup_cnt) == 0);
1637
1638 if (progress)
1639 memcpy(progress, &sdev->stat, sizeof(*progress));
1640
1641 mutex_lock(&fs_info->scrub_lock);
1642 dev->scrub_device = NULL;
1643 mutex_unlock(&fs_info->scrub_lock);
1644
1645 scrub_free_dev(sdev);
1646 scrub_workers_put(root);
1647
1648 return ret;
1649 }
1650
1651 int btrfs_scrub_pause(struct btrfs_root *root)
1652 {
1653 struct btrfs_fs_info *fs_info = root->fs_info;
1654
1655 mutex_lock(&fs_info->scrub_lock);
1656 atomic_inc(&fs_info->scrub_pause_req);
1657 while (atomic_read(&fs_info->scrubs_paused) !=
1658 atomic_read(&fs_info->scrubs_running)) {
1659 mutex_unlock(&fs_info->scrub_lock);
1660 wait_event(fs_info->scrub_pause_wait,
1661 atomic_read(&fs_info->scrubs_paused) ==
1662 atomic_read(&fs_info->scrubs_running));
1663 mutex_lock(&fs_info->scrub_lock);
1664 }
1665 mutex_unlock(&fs_info->scrub_lock);
1666
1667 return 0;
1668 }
1669
1670 int btrfs_scrub_continue(struct btrfs_root *root)
1671 {
1672 struct btrfs_fs_info *fs_info = root->fs_info;
1673
1674 atomic_dec(&fs_info->scrub_pause_req);
1675 wake_up(&fs_info->scrub_pause_wait);
1676 return 0;
1677 }
1678
1679 int btrfs_scrub_pause_super(struct btrfs_root *root)
1680 {
1681 down_write(&root->fs_info->scrub_super_lock);
1682 return 0;
1683 }
1684
1685 int btrfs_scrub_continue_super(struct btrfs_root *root)
1686 {
1687 up_write(&root->fs_info->scrub_super_lock);
1688 return 0;
1689 }
1690
1691 int btrfs_scrub_cancel(struct btrfs_root *root)
1692 {
1693 struct btrfs_fs_info *fs_info = root->fs_info;
1694
1695 mutex_lock(&fs_info->scrub_lock);
1696 if (!atomic_read(&fs_info->scrubs_running)) {
1697 mutex_unlock(&fs_info->scrub_lock);
1698 return -ENOTCONN;
1699 }
1700
1701 atomic_inc(&fs_info->scrub_cancel_req);
1702 while (atomic_read(&fs_info->scrubs_running)) {
1703 mutex_unlock(&fs_info->scrub_lock);
1704 wait_event(fs_info->scrub_pause_wait,
1705 atomic_read(&fs_info->scrubs_running) == 0);
1706 mutex_lock(&fs_info->scrub_lock);
1707 }
1708 atomic_dec(&fs_info->scrub_cancel_req);
1709 mutex_unlock(&fs_info->scrub_lock);
1710
1711 return 0;
1712 }
1713
1714 int btrfs_scrub_cancel_dev(struct btrfs_root *root, struct btrfs_device *dev)
1715 {
1716 struct btrfs_fs_info *fs_info = root->fs_info;
1717 struct scrub_dev *sdev;
1718
1719 mutex_lock(&fs_info->scrub_lock);
1720 sdev = dev->scrub_device;
1721 if (!sdev) {
1722 mutex_unlock(&fs_info->scrub_lock);
1723 return -ENOTCONN;
1724 }
1725 atomic_inc(&sdev->cancel_req);
1726 while (dev->scrub_device) {
1727 mutex_unlock(&fs_info->scrub_lock);
1728 wait_event(fs_info->scrub_pause_wait,
1729 dev->scrub_device == NULL);
1730 mutex_lock(&fs_info->scrub_lock);
1731 }
1732 mutex_unlock(&fs_info->scrub_lock);
1733
1734 return 0;
1735 }
1736 int btrfs_scrub_cancel_devid(struct btrfs_root *root, u64 devid)
1737 {
1738 struct btrfs_fs_info *fs_info = root->fs_info;
1739 struct btrfs_device *dev;
1740 int ret;
1741
1742 /*
1743 * we have to hold the device_list_mutex here so the device
1744 * does not go away in cancel_dev. FIXME: find a better solution
1745 */
1746 mutex_lock(&fs_info->fs_devices->device_list_mutex);
1747 dev = btrfs_find_device(root, devid, NULL, NULL);
1748 if (!dev) {
1749 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1750 return -ENODEV;
1751 }
1752 ret = btrfs_scrub_cancel_dev(root, dev);
1753 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1754
1755 return ret;
1756 }
1757
1758 int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
1759 struct btrfs_scrub_progress *progress)
1760 {
1761 struct btrfs_device *dev;
1762 struct scrub_dev *sdev = NULL;
1763
1764 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1765 dev = btrfs_find_device(root, devid, NULL, NULL);
1766 if (dev)
1767 sdev = dev->scrub_device;
1768 if (sdev)
1769 memcpy(progress, &sdev->stat, sizeof(*progress));
1770 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1771
1772 return dev ? (sdev ? 0 : -ENOTCONN) : -ENODEV;
1773 }