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asm-generic: Use __BITS_PER_LONG in statfs.h
[zen-stable.git] / fs / btrfs / scrub.c
blobb9b84cdfc3591c0b43f07f89a232eaa51d9acd0d
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
30 /*
31 * This is only the first step towards a full-features scrub. It reads all
32 * extent and super block and verifies the checksums. In case a bad checksum
33 * is found or the extent cannot be read, good data will be written back if
34 * any can be found.
35 *
36 * Future enhancements:
37 * - In case an unrepairable extent is encountered, track which files are
38 * affected and report them
39 * - In case of a read error on files with nodatasum, map the file and read
40 * the extent to trigger a writeback of the good copy
41 * - track and record media errors, throw out bad devices
42 * - add a mode to also read unallocated space
43 */
44
45 struct scrub_bio;
46 struct scrub_page;
47 struct scrub_dev;
48 static void scrub_bio_end_io(struct bio *bio, int err);
49 static void scrub_checksum(struct btrfs_work *work);
50 static int scrub_checksum_data(struct scrub_dev *sdev,
51 struct scrub_page *spag, void *buffer);
52 static int scrub_checksum_tree_block(struct scrub_dev *sdev,
53 struct scrub_page *spag, u64 logical,
54 void *buffer);
55 static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer);
56 static int scrub_fixup_check(struct scrub_bio *sbio, int ix);
57 static void scrub_fixup_end_io(struct bio *bio, int err);
58 static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector,
59 struct page *page);
60 static void scrub_fixup(struct scrub_bio *sbio, int ix);
61
62 #define SCRUB_PAGES_PER_BIO 16 /* 64k per bio */
63 #define SCRUB_BIOS_PER_DEV 16 /* 1 MB per device in flight */
64
65 struct scrub_page {
66 u64 flags; /* extent flags */
67 u64 generation;
68 int mirror_num;
69 int have_csum;
70 u8 csum[BTRFS_CSUM_SIZE];
71 };
72
73 struct scrub_bio {
74 int index;
75 struct scrub_dev *sdev;
76 struct bio *bio;
77 int err;
78 u64 logical;
79 u64 physical;
80 struct scrub_page spag[SCRUB_PAGES_PER_BIO];
81 u64 count;
82 int next_free;
83 struct btrfs_work work;
84 };
85
86 struct scrub_dev {
87 struct scrub_bio *bios[SCRUB_BIOS_PER_DEV];
88 struct btrfs_device *dev;
89 int first_free;
90 int curr;
91 atomic_t in_flight;
92 atomic_t fixup_cnt;
93 spinlock_t list_lock;
94 wait_queue_head_t list_wait;
95 u16 csum_size;
96 struct list_head csum_list;
97 atomic_t cancel_req;
98 int readonly;
99 /*
100 * statistics
101 */
102 struct btrfs_scrub_progress stat;
103 spinlock_t stat_lock;
104 };
105
106 struct scrub_fixup_nodatasum {
107 struct scrub_dev *sdev;
108 u64 logical;
109 struct btrfs_root *root;
110 struct btrfs_work work;
111 int mirror_num;
112 };
113
114 struct scrub_warning {
115 struct btrfs_path *path;
116 u64 extent_item_size;
117 char *scratch_buf;
118 char *msg_buf;
119 const char *errstr;
120 sector_t sector;
121 u64 logical;
122 struct btrfs_device *dev;
123 int msg_bufsize;
124 int scratch_bufsize;
125 };
126
127 static void scrub_free_csums(struct scrub_dev *sdev)
128 {
129 while (!list_empty(&sdev->csum_list)) {
130 struct btrfs_ordered_sum *sum;
131 sum = list_first_entry(&sdev->csum_list,
132 struct btrfs_ordered_sum, list);
133 list_del(&sum->list);
134 kfree(sum);
135 }
136 }
137
138 static void scrub_free_bio(struct bio *bio)
139 {
140 int i;
141 struct page *last_page = NULL;
142
143 if (!bio)
144 return;
145
146 for (i = 0; i < bio->bi_vcnt; ++i) {
147 if (bio->bi_io_vec[i].bv_page == last_page)
148 continue;
149 last_page = bio->bi_io_vec[i].bv_page;
150 __free_page(last_page);
151 }
152 bio_put(bio);
153 }
154
155 static noinline_for_stack void scrub_free_dev(struct scrub_dev *sdev)
156 {
157 int i;
158
159 if (!sdev)
160 return;
161
162 for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
163 struct scrub_bio *sbio = sdev->bios[i];
164
165 if (!sbio)
166 break;
167
168 scrub_free_bio(sbio->bio);
169 kfree(sbio);
170 }
171
172 scrub_free_csums(sdev);
173 kfree(sdev);
174 }
175
176 static noinline_for_stack
177 struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev)
178 {
179 struct scrub_dev *sdev;
180 int i;
181 struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
182
183 sdev = kzalloc(sizeof(*sdev), GFP_NOFS);
184 if (!sdev)
185 goto nomem;
186 sdev->dev = dev;
187 for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
188 struct scrub_bio *sbio;
189
190 sbio = kzalloc(sizeof(*sbio), GFP_NOFS);
191 if (!sbio)
192 goto nomem;
193 sdev->bios[i] = sbio;
194
195 sbio->index = i;
196 sbio->sdev = sdev;
197 sbio->count = 0;
198 sbio->work.func = scrub_checksum;
199
200 if (i != SCRUB_BIOS_PER_DEV-1)
201 sdev->bios[i]->next_free = i + 1;
202 else
203 sdev->bios[i]->next_free = -1;
204 }
205 sdev->first_free = 0;
206 sdev->curr = -1;
207 atomic_set(&sdev->in_flight, 0);
208 atomic_set(&sdev->fixup_cnt, 0);
209 atomic_set(&sdev->cancel_req, 0);
210 sdev->csum_size = btrfs_super_csum_size(fs_info->super_copy);
211 INIT_LIST_HEAD(&sdev->csum_list);
212
213 spin_lock_init(&sdev->list_lock);
214 spin_lock_init(&sdev->stat_lock);
215 init_waitqueue_head(&sdev->list_wait);
216 return sdev;
217
218 nomem:
219 scrub_free_dev(sdev);
220 return ERR_PTR(-ENOMEM);
221 }
222
223 static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root, void *ctx)
224 {
225 u64 isize;
226 u32 nlink;
227 int ret;
228 int i;
229 struct extent_buffer *eb;
230 struct btrfs_inode_item *inode_item;
231 struct scrub_warning *swarn = ctx;
232 struct btrfs_fs_info *fs_info = swarn->dev->dev_root->fs_info;
233 struct inode_fs_paths *ipath = NULL;
234 struct btrfs_root *local_root;
235 struct btrfs_key root_key;
236
237 root_key.objectid = root;
238 root_key.type = BTRFS_ROOT_ITEM_KEY;
239 root_key.offset = (u64)-1;
240 local_root = btrfs_read_fs_root_no_name(fs_info, &root_key);
241 if (IS_ERR(local_root)) {
242 ret = PTR_ERR(local_root);
243 goto err;
244 }
245
246 ret = inode_item_info(inum, 0, local_root, swarn->path);
247 if (ret) {
248 btrfs_release_path(swarn->path);
249 goto err;
250 }
251
252 eb = swarn->path->nodes[0];
253 inode_item = btrfs_item_ptr(eb, swarn->path->slots[0],
254 struct btrfs_inode_item);
255 isize = btrfs_inode_size(eb, inode_item);
256 nlink = btrfs_inode_nlink(eb, inode_item);
257 btrfs_release_path(swarn->path);
258
259 ipath = init_ipath(4096, local_root, swarn->path);
260 if (IS_ERR(ipath)) {
261 ret = PTR_ERR(ipath);
262 ipath = NULL;
263 goto err;
264 }
265 ret = paths_from_inode(inum, ipath);
266
267 if (ret < 0)
268 goto err;
269
270 /*
271 * we deliberately ignore the bit ipath might have been too small to
272 * hold all of the paths here
273 */
274 for (i = 0; i < ipath->fspath->elem_cnt; ++i)
275 printk(KERN_WARNING "btrfs: %s at logical %llu on dev "
276 "%s, sector %llu, root %llu, inode %llu, offset %llu, "
277 "length %llu, links %u (path: %s)\n", swarn->errstr,
278 swarn->logical, swarn->dev->name,
279 (unsigned long long)swarn->sector, root, inum, offset,
280 min(isize - offset, (u64)PAGE_SIZE), nlink,
281 (char *)(unsigned long)ipath->fspath->val[i]);
282
283 free_ipath(ipath);
284 return 0;
285
286 err:
287 printk(KERN_WARNING "btrfs: %s at logical %llu on dev "
288 "%s, sector %llu, root %llu, inode %llu, offset %llu: path "
289 "resolving failed with ret=%d\n", swarn->errstr,
290 swarn->logical, swarn->dev->name,
291 (unsigned long long)swarn->sector, root, inum, offset, ret);
292
293 free_ipath(ipath);
294 return 0;
295 }
296
297 static void scrub_print_warning(const char *errstr, struct scrub_bio *sbio,
298 int ix)
299 {
300 struct btrfs_device *dev = sbio->sdev->dev;
301 struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
302 struct btrfs_path *path;
303 struct btrfs_key found_key;
304 struct extent_buffer *eb;
305 struct btrfs_extent_item *ei;
306 struct scrub_warning swarn;
307 u32 item_size;
308 int ret;
309 u64 ref_root;
310 u8 ref_level;
311 unsigned long ptr = 0;
312 const int bufsize = 4096;
313 u64 extent_item_pos;
314
315 path = btrfs_alloc_path();
316
317 swarn.scratch_buf = kmalloc(bufsize, GFP_NOFS);
318 swarn.msg_buf = kmalloc(bufsize, GFP_NOFS);
319 swarn.sector = (sbio->physical + ix * PAGE_SIZE) >> 9;
320 swarn.logical = sbio->logical + ix * PAGE_SIZE;
321 swarn.errstr = errstr;
322 swarn.dev = dev;
323 swarn.msg_bufsize = bufsize;
324 swarn.scratch_bufsize = bufsize;
325
326 if (!path || !swarn.scratch_buf || !swarn.msg_buf)
327 goto out;
328
329 ret = extent_from_logical(fs_info, swarn.logical, path, &found_key);
330 if (ret < 0)
331 goto out;
332
333 extent_item_pos = swarn.logical - found_key.objectid;
334 swarn.extent_item_size = found_key.offset;
335
336 eb = path->nodes[0];
337 ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
338 item_size = btrfs_item_size_nr(eb, path->slots[0]);
339 btrfs_release_path(path);
340
341 if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
342 do {
343 ret = tree_backref_for_extent(&ptr, eb, ei, item_size,
344 &ref_root, &ref_level);
345 printk(KERN_WARNING "%s at logical %llu on dev %s, "
346 "sector %llu: metadata %s (level %d) in tree "
347 "%llu\n", errstr, swarn.logical, dev->name,
348 (unsigned long long)swarn.sector,
349 ref_level ? "node" : "leaf",
350 ret < 0 ? -1 : ref_level,
351 ret < 0 ? -1 : ref_root);
352 } while (ret != 1);
353 } else {
354 swarn.path = path;
355 iterate_extent_inodes(fs_info, found_key.objectid,
356 extent_item_pos, 1,
357 scrub_print_warning_inode, &swarn);
358 }
359
360 out:
361 btrfs_free_path(path);
362 kfree(swarn.scratch_buf);
363 kfree(swarn.msg_buf);
364 }
365
366 static int scrub_fixup_readpage(u64 inum, u64 offset, u64 root, void *ctx)
367 {
368 struct page *page = NULL;
369 unsigned long index;
370 struct scrub_fixup_nodatasum *fixup = ctx;
371 int ret;
372 int corrected = 0;
373 struct btrfs_key key;
374 struct inode *inode = NULL;
375 u64 end = offset + PAGE_SIZE - 1;
376 struct btrfs_root *local_root;
377
378 key.objectid = root;
379 key.type = BTRFS_ROOT_ITEM_KEY;
380 key.offset = (u64)-1;
381 local_root = btrfs_read_fs_root_no_name(fixup->root->fs_info, &key);
382 if (IS_ERR(local_root))
383 return PTR_ERR(local_root);
384
385 key.type = BTRFS_INODE_ITEM_KEY;
386 key.objectid = inum;
387 key.offset = 0;
388 inode = btrfs_iget(fixup->root->fs_info->sb, &key, local_root, NULL);
389 if (IS_ERR(inode))
390 return PTR_ERR(inode);
391
392 index = offset >> PAGE_CACHE_SHIFT;
393
394 page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
395 if (!page) {
396 ret = -ENOMEM;
397 goto out;
398 }
399
400 if (PageUptodate(page)) {
401 struct btrfs_mapping_tree *map_tree;
402 if (PageDirty(page)) {
403 /*
404 * we need to write the data to the defect sector. the
405 * data that was in that sector is not in memory,
406 * because the page was modified. we must not write the
407 * modified page to that sector.
408 *
409 * TODO: what could be done here: wait for the delalloc
410 * runner to write out that page (might involve
411 * COW) and see whether the sector is still
412 * referenced afterwards.
413 *
414 * For the meantime, we'll treat this error
415 * incorrectable, although there is a chance that a
416 * later scrub will find the bad sector again and that
417 * there's no dirty page in memory, then.
418 */
419 ret = -EIO;
420 goto out;
421 }
422 map_tree = &BTRFS_I(inode)->root->fs_info->mapping_tree;
423 ret = repair_io_failure(map_tree, offset, PAGE_SIZE,
424 fixup->logical, page,
425 fixup->mirror_num);
426 unlock_page(page);
427 corrected = !ret;
428 } else {
429 /*
430 * we need to get good data first. the general readpage path
431 * will call repair_io_failure for us, we just have to make
432 * sure we read the bad mirror.
433 */
434 ret = set_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
435 EXTENT_DAMAGED, GFP_NOFS);
436 if (ret) {
437 /* set_extent_bits should give proper error */
438 WARN_ON(ret > 0);
439 if (ret > 0)
440 ret = -EFAULT;
441 goto out;
442 }
443
444 ret = extent_read_full_page(&BTRFS_I(inode)->io_tree, page,
445 btrfs_get_extent,
446 fixup->mirror_num);
447 wait_on_page_locked(page);
448
449 corrected = !test_range_bit(&BTRFS_I(inode)->io_tree, offset,
450 end, EXTENT_DAMAGED, 0, NULL);
451 if (!corrected)
452 clear_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
453 EXTENT_DAMAGED, GFP_NOFS);
454 }
455
456 out:
457 if (page)
458 put_page(page);
459 if (inode)
460 iput(inode);
461
462 if (ret < 0)
463 return ret;
464
465 if (ret == 0 && corrected) {
466 /*
467 * we only need to call readpage for one of the inodes belonging
468 * to this extent. so make iterate_extent_inodes stop
469 */
470 return 1;
471 }
472
473 return -EIO;
474 }
475
476 static void scrub_fixup_nodatasum(struct btrfs_work *work)
477 {
478 int ret;
479 struct scrub_fixup_nodatasum *fixup;
480 struct scrub_dev *sdev;
481 struct btrfs_trans_handle *trans = NULL;
482 struct btrfs_fs_info *fs_info;
483 struct btrfs_path *path;
484 int uncorrectable = 0;
485
486 fixup = container_of(work, struct scrub_fixup_nodatasum, work);
487 sdev = fixup->sdev;
488 fs_info = fixup->root->fs_info;
489
490 path = btrfs_alloc_path();
491 if (!path) {
492 spin_lock(&sdev->stat_lock);
493 ++sdev->stat.malloc_errors;
494 spin_unlock(&sdev->stat_lock);
495 uncorrectable = 1;
496 goto out;
497 }
498
499 trans = btrfs_join_transaction(fixup->root);
500 if (IS_ERR(trans)) {
501 uncorrectable = 1;
502 goto out;
503 }
504
505 /*
506 * the idea is to trigger a regular read through the standard path. we
507 * read a page from the (failed) logical address by specifying the
508 * corresponding copynum of the failed sector. thus, that readpage is
509 * expected to fail.
510 * that is the point where on-the-fly error correction will kick in
511 * (once it's finished) and rewrite the failed sector if a good copy
512 * can be found.
513 */
514 ret = iterate_inodes_from_logical(fixup->logical, fixup->root->fs_info,
515 path, scrub_fixup_readpage,
516 fixup);
517 if (ret < 0) {
518 uncorrectable = 1;
519 goto out;
520 }
521 WARN_ON(ret != 1);
522
523 spin_lock(&sdev->stat_lock);
524 ++sdev->stat.corrected_errors;
525 spin_unlock(&sdev->stat_lock);
526
527 out:
528 if (trans && !IS_ERR(trans))
529 btrfs_end_transaction(trans, fixup->root);
530 if (uncorrectable) {
531 spin_lock(&sdev->stat_lock);
532 ++sdev->stat.uncorrectable_errors;
533 spin_unlock(&sdev->stat_lock);
534 printk_ratelimited(KERN_ERR "btrfs: unable to fixup "
535 "(nodatasum) error at logical %llu\n",
536 fixup->logical);
537 }
538
539 btrfs_free_path(path);
540 kfree(fixup);
541
542 /* see caller why we're pretending to be paused in the scrub counters */
543 mutex_lock(&fs_info->scrub_lock);
544 atomic_dec(&fs_info->scrubs_running);
545 atomic_dec(&fs_info->scrubs_paused);
546 mutex_unlock(&fs_info->scrub_lock);
547 atomic_dec(&sdev->fixup_cnt);
548 wake_up(&fs_info->scrub_pause_wait);
549 wake_up(&sdev->list_wait);
550 }
551
552 /*
553 * scrub_recheck_error gets called when either verification of the page
554 * failed or the bio failed to read, e.g. with EIO. In the latter case,
555 * recheck_error gets called for every page in the bio, even though only
556 * one may be bad
557 */
558 static int scrub_recheck_error(struct scrub_bio *sbio, int ix)
559 {
560 struct scrub_dev *sdev = sbio->sdev;
561 u64 sector = (sbio->physical + ix * PAGE_SIZE) >> 9;
562 static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
563 DEFAULT_RATELIMIT_BURST);
564
565 if (sbio->err) {
566 if (scrub_fixup_io(READ, sbio->sdev->dev->bdev, sector,
567 sbio->bio->bi_io_vec[ix].bv_page) == 0) {
568 if (scrub_fixup_check(sbio, ix) == 0)
569 return 0;
570 }
571 if (__ratelimit(&_rs))
572 scrub_print_warning("i/o error", sbio, ix);
573 } else {
574 if (__ratelimit(&_rs))
575 scrub_print_warning("checksum error", sbio, ix);
576 }
577
578 spin_lock(&sdev->stat_lock);
579 ++sdev->stat.read_errors;
580 spin_unlock(&sdev->stat_lock);
581
582 scrub_fixup(sbio, ix);
583 return 1;
584 }
585
586 static int scrub_fixup_check(struct scrub_bio *sbio, int ix)
587 {
588 int ret = 1;
589 struct page *page;
590 void *buffer;
591 u64 flags = sbio->spag[ix].flags;
592
593 page = sbio->bio->bi_io_vec[ix].bv_page;
594 buffer = kmap_atomic(page, KM_USER0);
595 if (flags & BTRFS_EXTENT_FLAG_DATA) {
596 ret = scrub_checksum_data(sbio->sdev,
597 sbio->spag + ix, buffer);
598 } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
599 ret = scrub_checksum_tree_block(sbio->sdev,
600 sbio->spag + ix,
601 sbio->logical + ix * PAGE_SIZE,
602 buffer);
603 } else {
604 WARN_ON(1);
605 }
606 kunmap_atomic(buffer, KM_USER0);
607
608 return ret;
609 }
610
611 static void scrub_fixup_end_io(struct bio *bio, int err)
612 {
613 complete((struct completion *)bio->bi_private);
614 }
615
616 static void scrub_fixup(struct scrub_bio *sbio, int ix)
617 {
618 struct scrub_dev *sdev = sbio->sdev;
619 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
620 struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
621 struct btrfs_bio *bbio = NULL;
622 struct scrub_fixup_nodatasum *fixup;
623 u64 logical = sbio->logical + ix * PAGE_SIZE;
624 u64 length;
625 int i;
626 int ret;
627 DECLARE_COMPLETION_ONSTACK(complete);
628
629 if ((sbio->spag[ix].flags & BTRFS_EXTENT_FLAG_DATA) &&
630 (sbio->spag[ix].have_csum == 0)) {
631 fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
632 if (!fixup)
633 goto uncorrectable;
634 fixup->sdev = sdev;
635 fixup->logical = logical;
636 fixup->root = fs_info->extent_root;
637 fixup->mirror_num = sbio->spag[ix].mirror_num;
638 /*
639 * increment scrubs_running to prevent cancel requests from
640 * completing as long as a fixup worker is running. we must also
641 * increment scrubs_paused to prevent deadlocking on pause
642 * requests used for transactions commits (as the worker uses a
643 * transaction context). it is safe to regard the fixup worker
644 * as paused for all matters practical. effectively, we only
645 * avoid cancellation requests from completing.
646 */
647 mutex_lock(&fs_info->scrub_lock);
648 atomic_inc(&fs_info->scrubs_running);
649 atomic_inc(&fs_info->scrubs_paused);
650 mutex_unlock(&fs_info->scrub_lock);
651 atomic_inc(&sdev->fixup_cnt);
652 fixup->work.func = scrub_fixup_nodatasum;
653 btrfs_queue_worker(&fs_info->scrub_workers, &fixup->work);
654 return;
655 }
656
657 length = PAGE_SIZE;
658 ret = btrfs_map_block(map_tree, REQ_WRITE, logical, &length,
659 &bbio, 0);
660 if (ret || !bbio || length < PAGE_SIZE) {
661 printk(KERN_ERR
662 "scrub_fixup: btrfs_map_block failed us for %llu\n",
663 (unsigned long long)logical);
664 WARN_ON(1);
665 kfree(bbio);
666 return;
667 }
668
669 if (bbio->num_stripes == 1)
670 /* there aren't any replicas */
671 goto uncorrectable;
672
673 /*
674 * first find a good copy
675 */
676 for (i = 0; i < bbio->num_stripes; ++i) {
677 if (i + 1 == sbio->spag[ix].mirror_num)
678 continue;
679
680 if (scrub_fixup_io(READ, bbio->stripes[i].dev->bdev,
681 bbio->stripes[i].physical >> 9,
682 sbio->bio->bi_io_vec[ix].bv_page)) {
683 /* I/O-error, this is not a good copy */
684 continue;
685 }
686
687 if (scrub_fixup_check(sbio, ix) == 0)
688 break;
689 }
690 if (i == bbio->num_stripes)
691 goto uncorrectable;
692
693 if (!sdev->readonly) {
694 /*
695 * bi_io_vec[ix].bv_page now contains good data, write it back
696 */
697 if (scrub_fixup_io(WRITE, sdev->dev->bdev,
698 (sbio->physical + ix * PAGE_SIZE) >> 9,
699 sbio->bio->bi_io_vec[ix].bv_page)) {
700 /* I/O-error, writeback failed, give up */
701 goto uncorrectable;
702 }
703 }
704
705 kfree(bbio);
706 spin_lock(&sdev->stat_lock);
707 ++sdev->stat.corrected_errors;
708 spin_unlock(&sdev->stat_lock);
709
710 printk_ratelimited(KERN_ERR "btrfs: fixed up error at logical %llu\n",
711 (unsigned long long)logical);
712 return;
713
714 uncorrectable:
715 kfree(bbio);
716 spin_lock(&sdev->stat_lock);
717 ++sdev->stat.uncorrectable_errors;
718 spin_unlock(&sdev->stat_lock);
719
720 printk_ratelimited(KERN_ERR "btrfs: unable to fixup (regular) error at "
721 "logical %llu\n", (unsigned long long)logical);
722 }
723
724 static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector,
725 struct page *page)
726 {
727 struct bio *bio = NULL;
728 int ret;
729 DECLARE_COMPLETION_ONSTACK(complete);
730
731 bio = bio_alloc(GFP_NOFS, 1);
732 bio->bi_bdev = bdev;
733 bio->bi_sector = sector;
734 bio_add_page(bio, page, PAGE_SIZE, 0);
735 bio->bi_end_io = scrub_fixup_end_io;
736 bio->bi_private = &complete;
737 btrfsic_submit_bio(rw, bio);
738
739 /* this will also unplug the queue */
740 wait_for_completion(&complete);
741
742 ret = !test_bit(BIO_UPTODATE, &bio->bi_flags);
743 bio_put(bio);
744 return ret;
745 }
746
747 static void scrub_bio_end_io(struct bio *bio, int err)
748 {
749 struct scrub_bio *sbio = bio->bi_private;
750 struct scrub_dev *sdev = sbio->sdev;
751 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
752
753 sbio->err = err;
754 sbio->bio = bio;
755
756 btrfs_queue_worker(&fs_info->scrub_workers, &sbio->work);
757 }
758
759 static void scrub_checksum(struct btrfs_work *work)
760 {
761 struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
762 struct scrub_dev *sdev = sbio->sdev;
763 struct page *page;
764 void *buffer;
765 int i;
766 u64 flags;
767 u64 logical;
768 int ret;
769
770 if (sbio->err) {
771 ret = 0;
772 for (i = 0; i < sbio->count; ++i)
773 ret |= scrub_recheck_error(sbio, i);
774 if (!ret) {
775 spin_lock(&sdev->stat_lock);
776 ++sdev->stat.unverified_errors;
777 spin_unlock(&sdev->stat_lock);
778 }
779
780 sbio->bio->bi_flags &= ~(BIO_POOL_MASK - 1);
781 sbio->bio->bi_flags |= 1 << BIO_UPTODATE;
782 sbio->bio->bi_phys_segments = 0;
783 sbio->bio->bi_idx = 0;
784
785 for (i = 0; i < sbio->count; i++) {
786 struct bio_vec *bi;
787 bi = &sbio->bio->bi_io_vec[i];
788 bi->bv_offset = 0;
789 bi->bv_len = PAGE_SIZE;
790 }
791 goto out;
792 }
793 for (i = 0; i < sbio->count; ++i) {
794 page = sbio->bio->bi_io_vec[i].bv_page;
795 buffer = kmap_atomic(page, KM_USER0);
796 flags = sbio->spag[i].flags;
797 logical = sbio->logical + i * PAGE_SIZE;
798 ret = 0;
799 if (flags & BTRFS_EXTENT_FLAG_DATA) {
800 ret = scrub_checksum_data(sdev, sbio->spag + i, buffer);
801 } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
802 ret = scrub_checksum_tree_block(sdev, sbio->spag + i,
803 logical, buffer);
804 } else if (flags & BTRFS_EXTENT_FLAG_SUPER) {
805 BUG_ON(i);
806 (void)scrub_checksum_super(sbio, buffer);
807 } else {
808 WARN_ON(1);
809 }
810 kunmap_atomic(buffer, KM_USER0);
811 if (ret) {
812 ret = scrub_recheck_error(sbio, i);
813 if (!ret) {
814 spin_lock(&sdev->stat_lock);
815 ++sdev->stat.unverified_errors;
816 spin_unlock(&sdev->stat_lock);
817 }
818 }
819 }
820
821 out:
822 scrub_free_bio(sbio->bio);
823 sbio->bio = NULL;
824 spin_lock(&sdev->list_lock);
825 sbio->next_free = sdev->first_free;
826 sdev->first_free = sbio->index;
827 spin_unlock(&sdev->list_lock);
828 atomic_dec(&sdev->in_flight);
829 wake_up(&sdev->list_wait);
830 }
831
832 static int scrub_checksum_data(struct scrub_dev *sdev,
833 struct scrub_page *spag, void *buffer)
834 {
835 u8 csum[BTRFS_CSUM_SIZE];
836 u32 crc = ~(u32)0;
837 int fail = 0;
838 struct btrfs_root *root = sdev->dev->dev_root;
839
840 if (!spag->have_csum)
841 return 0;
842
843 crc = btrfs_csum_data(root, buffer, crc, PAGE_SIZE);
844 btrfs_csum_final(crc, csum);
845 if (memcmp(csum, spag->csum, sdev->csum_size))
846 fail = 1;
847
848 spin_lock(&sdev->stat_lock);
849 ++sdev->stat.data_extents_scrubbed;
850 sdev->stat.data_bytes_scrubbed += PAGE_SIZE;
851 if (fail)
852 ++sdev->stat.csum_errors;
853 spin_unlock(&sdev->stat_lock);
854
855 return fail;
856 }
857
858 static int scrub_checksum_tree_block(struct scrub_dev *sdev,
859 struct scrub_page *spag, u64 logical,
860 void *buffer)
861 {
862 struct btrfs_header *h;
863 struct btrfs_root *root = sdev->dev->dev_root;
864 struct btrfs_fs_info *fs_info = root->fs_info;
865 u8 csum[BTRFS_CSUM_SIZE];
866 u32 crc = ~(u32)0;
867 int fail = 0;
868 int crc_fail = 0;
869
870 /*
871 * we don't use the getter functions here, as we
872 * a) don't have an extent buffer and
873 * b) the page is already kmapped
874 */
875 h = (struct btrfs_header *)buffer;
876
877 if (logical != le64_to_cpu(h->bytenr))
878 ++fail;
879
880 if (spag->generation != le64_to_cpu(h->generation))
881 ++fail;
882
883 if (memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
884 ++fail;
885
886 if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
887 BTRFS_UUID_SIZE))
888 ++fail;
889
890 crc = btrfs_csum_data(root, buffer + BTRFS_CSUM_SIZE, crc,
891 PAGE_SIZE - BTRFS_CSUM_SIZE);
892 btrfs_csum_final(crc, csum);
893 if (memcmp(csum, h->csum, sdev->csum_size))
894 ++crc_fail;
895
896 spin_lock(&sdev->stat_lock);
897 ++sdev->stat.tree_extents_scrubbed;
898 sdev->stat.tree_bytes_scrubbed += PAGE_SIZE;
899 if (crc_fail)
900 ++sdev->stat.csum_errors;
901 if (fail)
902 ++sdev->stat.verify_errors;
903 spin_unlock(&sdev->stat_lock);
904
905 return fail || crc_fail;
906 }
907
908 static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer)
909 {
910 struct btrfs_super_block *s;
911 u64 logical;
912 struct scrub_dev *sdev = sbio->sdev;
913 struct btrfs_root *root = sdev->dev->dev_root;
914 struct btrfs_fs_info *fs_info = root->fs_info;
915 u8 csum[BTRFS_CSUM_SIZE];
916 u32 crc = ~(u32)0;
917 int fail = 0;
918
919 s = (struct btrfs_super_block *)buffer;
920 logical = sbio->logical;
921
922 if (logical != le64_to_cpu(s->bytenr))
923 ++fail;
924
925 if (sbio->spag[0].generation != le64_to_cpu(s->generation))
926 ++fail;
927
928 if (memcmp(s->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
929 ++fail;
930
931 crc = btrfs_csum_data(root, buffer + BTRFS_CSUM_SIZE, crc,
932 PAGE_SIZE - BTRFS_CSUM_SIZE);
933 btrfs_csum_final(crc, csum);
934 if (memcmp(csum, s->csum, sbio->sdev->csum_size))
935 ++fail;
936
937 if (fail) {
938 /*
939 * if we find an error in a super block, we just report it.
940 * They will get written with the next transaction commit
941 * anyway
942 */
943 spin_lock(&sdev->stat_lock);
944 ++sdev->stat.super_errors;
945 spin_unlock(&sdev->stat_lock);
946 }
947
948 return fail;
949 }
950
951 static int scrub_submit(struct scrub_dev *sdev)
952 {
953 struct scrub_bio *sbio;
954
955 if (sdev->curr == -1)
956 return 0;
957
958 sbio = sdev->bios[sdev->curr];
959 sbio->err = 0;
960 sdev->curr = -1;
961 atomic_inc(&sdev->in_flight);
962
963 btrfsic_submit_bio(READ, sbio->bio);
964
965 return 0;
966 }
967
968 static int scrub_page(struct scrub_dev *sdev, u64 logical, u64 len,
969 u64 physical, u64 flags, u64 gen, int mirror_num,
970 u8 *csum, int force)
971 {
972 struct scrub_bio *sbio;
973 struct page *page;
974 int ret;
975
976 again:
977 /*
978 * grab a fresh bio or wait for one to become available
979 */
980 while (sdev->curr == -1) {
981 spin_lock(&sdev->list_lock);
982 sdev->curr = sdev->first_free;
983 if (sdev->curr != -1) {
984 sdev->first_free = sdev->bios[sdev->curr]->next_free;
985 sdev->bios[sdev->curr]->next_free = -1;
986 sdev->bios[sdev->curr]->count = 0;
987 spin_unlock(&sdev->list_lock);
988 } else {
989 spin_unlock(&sdev->list_lock);
990 wait_event(sdev->list_wait, sdev->first_free != -1);
991 }
992 }
993 sbio = sdev->bios[sdev->curr];
994 if (sbio->count == 0) {
995 struct bio *bio;
996
997 sbio->physical = physical;
998 sbio->logical = logical;
999 bio = bio_alloc(GFP_NOFS, SCRUB_PAGES_PER_BIO);
1000 if (!bio)
1001 return -ENOMEM;
1002
1003 bio->bi_private = sbio;
1004 bio->bi_end_io = scrub_bio_end_io;
1005 bio->bi_bdev = sdev->dev->bdev;
1006 bio->bi_sector = sbio->physical >> 9;
1007 sbio->err = 0;
1008 sbio->bio = bio;
1009 } else if (sbio->physical + sbio->count * PAGE_SIZE != physical ||
1010 sbio->logical + sbio->count * PAGE_SIZE != logical) {
1011 ret = scrub_submit(sdev);
1012 if (ret)
1013 return ret;
1014 goto again;
1015 }
1016 sbio->spag[sbio->count].flags = flags;
1017 sbio->spag[sbio->count].generation = gen;
1018 sbio->spag[sbio->count].have_csum = 0;
1019 sbio->spag[sbio->count].mirror_num = mirror_num;
1020
1021 page = alloc_page(GFP_NOFS);
1022 if (!page)
1023 return -ENOMEM;
1024
1025 ret = bio_add_page(sbio->bio, page, PAGE_SIZE, 0);
1026 if (!ret) {
1027 __free_page(page);
1028 ret = scrub_submit(sdev);
1029 if (ret)
1030 return ret;
1031 goto again;
1032 }
1033
1034 if (csum) {
1035 sbio->spag[sbio->count].have_csum = 1;
1036 memcpy(sbio->spag[sbio->count].csum, csum, sdev->csum_size);
1037 }
1038 ++sbio->count;
1039 if (sbio->count == SCRUB_PAGES_PER_BIO || force) {
1040 int ret;
1041
1042 ret = scrub_submit(sdev);
1043 if (ret)
1044 return ret;
1045 }
1046
1047 return 0;
1048 }
1049
1050 static int scrub_find_csum(struct scrub_dev *sdev, u64 logical, u64 len,
1051 u8 *csum)
1052 {
1053 struct btrfs_ordered_sum *sum = NULL;
1054 int ret = 0;
1055 unsigned long i;
1056 unsigned long num_sectors;
1057 u32 sectorsize = sdev->dev->dev_root->sectorsize;
1058
1059 while (!list_empty(&sdev->csum_list)) {
1060 sum = list_first_entry(&sdev->csum_list,
1061 struct btrfs_ordered_sum, list);
1062 if (sum->bytenr > logical)
1063 return 0;
1064 if (sum->bytenr + sum->len > logical)
1065 break;
1066
1067 ++sdev->stat.csum_discards;
1068 list_del(&sum->list);
1069 kfree(sum);
1070 sum = NULL;
1071 }
1072 if (!sum)
1073 return 0;
1074
1075 num_sectors = sum->len / sectorsize;
1076 for (i = 0; i < num_sectors; ++i) {
1077 if (sum->sums[i].bytenr == logical) {
1078 memcpy(csum, &sum->sums[i].sum, sdev->csum_size);
1079 ret = 1;
1080 break;
1081 }
1082 }
1083 if (ret && i == num_sectors - 1) {
1084 list_del(&sum->list);
1085 kfree(sum);
1086 }
1087 return ret;
1088 }
1089
1090 /* scrub extent tries to collect up to 64 kB for each bio */
1091 static int scrub_extent(struct scrub_dev *sdev, u64 logical, u64 len,
1092 u64 physical, u64 flags, u64 gen, int mirror_num)
1093 {
1094 int ret;
1095 u8 csum[BTRFS_CSUM_SIZE];
1096
1097 while (len) {
1098 u64 l = min_t(u64, len, PAGE_SIZE);
1099 int have_csum = 0;
1100
1101 if (flags & BTRFS_EXTENT_FLAG_DATA) {
1102 /* push csums to sbio */
1103 have_csum = scrub_find_csum(sdev, logical, l, csum);
1104 if (have_csum == 0)
1105 ++sdev->stat.no_csum;
1106 }
1107 ret = scrub_page(sdev, logical, l, physical, flags, gen,
1108 mirror_num, have_csum ? csum : NULL, 0);
1109 if (ret)
1110 return ret;
1111 len -= l;
1112 logical += l;
1113 physical += l;
1114 }
1115 return 0;
1116 }
1117
1118 static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev,
1119 struct map_lookup *map, int num, u64 base, u64 length)
1120 {
1121 struct btrfs_path *path;
1122 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
1123 struct btrfs_root *root = fs_info->extent_root;
1124 struct btrfs_root *csum_root = fs_info->csum_root;
1125 struct btrfs_extent_item *extent;
1126 struct blk_plug plug;
1127 u64 flags;
1128 int ret;
1129 int slot;
1130 int i;
1131 u64 nstripes;
1132 struct extent_buffer *l;
1133 struct btrfs_key key;
1134 u64 physical;
1135 u64 logical;
1136 u64 generation;
1137 int mirror_num;
1138 struct reada_control *reada1;
1139 struct reada_control *reada2;
1140 struct btrfs_key key_start;
1141 struct btrfs_key key_end;
1142
1143 u64 increment = map->stripe_len;
1144 u64 offset;
1145
1146 nstripes = length;
1147 offset = 0;
1148 do_div(nstripes, map->stripe_len);
1149 if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
1150 offset = map->stripe_len * num;
1151 increment = map->stripe_len * map->num_stripes;
1152 mirror_num = 1;
1153 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1154 int factor = map->num_stripes / map->sub_stripes;
1155 offset = map->stripe_len * (num / map->sub_stripes);
1156 increment = map->stripe_len * factor;
1157 mirror_num = num % map->sub_stripes + 1;
1158 } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
1159 increment = map->stripe_len;
1160 mirror_num = num % map->num_stripes + 1;
1161 } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
1162 increment = map->stripe_len;
1163 mirror_num = num % map->num_stripes + 1;
1164 } else {
1165 increment = map->stripe_len;
1166 mirror_num = 1;
1167 }
1168
1169 path = btrfs_alloc_path();
1170 if (!path)
1171 return -ENOMEM;
1172
1173 path->search_commit_root = 1;
1174 path->skip_locking = 1;
1175
1176 /*
1177 * trigger the readahead for extent tree csum tree and wait for
1178 * completion. During readahead, the scrub is officially paused
1179 * to not hold off transaction commits
1180 */
1181 logical = base + offset;
1182
1183 wait_event(sdev->list_wait,
1184 atomic_read(&sdev->in_flight) == 0);
1185 atomic_inc(&fs_info->scrubs_paused);
1186 wake_up(&fs_info->scrub_pause_wait);
1187
1188 /* FIXME it might be better to start readahead at commit root */
1189 key_start.objectid = logical;
1190 key_start.type = BTRFS_EXTENT_ITEM_KEY;
1191 key_start.offset = (u64)0;
1192 key_end.objectid = base + offset + nstripes * increment;
1193 key_end.type = BTRFS_EXTENT_ITEM_KEY;
1194 key_end.offset = (u64)0;
1195 reada1 = btrfs_reada_add(root, &key_start, &key_end);
1196
1197 key_start.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
1198 key_start.type = BTRFS_EXTENT_CSUM_KEY;
1199 key_start.offset = logical;
1200 key_end.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
1201 key_end.type = BTRFS_EXTENT_CSUM_KEY;
1202 key_end.offset = base + offset + nstripes * increment;
1203 reada2 = btrfs_reada_add(csum_root, &key_start, &key_end);
1204
1205 if (!IS_ERR(reada1))
1206 btrfs_reada_wait(reada1);
1207 if (!IS_ERR(reada2))
1208 btrfs_reada_wait(reada2);
1209
1210 mutex_lock(&fs_info->scrub_lock);
1211 while (atomic_read(&fs_info->scrub_pause_req)) {
1212 mutex_unlock(&fs_info->scrub_lock);
1213 wait_event(fs_info->scrub_pause_wait,
1214 atomic_read(&fs_info->scrub_pause_req) == 0);
1215 mutex_lock(&fs_info->scrub_lock);
1216 }
1217 atomic_dec(&fs_info->scrubs_paused);
1218 mutex_unlock(&fs_info->scrub_lock);
1219 wake_up(&fs_info->scrub_pause_wait);
1220
1221 /*
1222 * collect all data csums for the stripe to avoid seeking during
1223 * the scrub. This might currently (crc32) end up to be about 1MB
1224 */
1225 blk_start_plug(&plug);
1226
1227 /*
1228 * now find all extents for each stripe and scrub them
1229 */
1230 logical = base + offset;
1231 physical = map->stripes[num].physical;
1232 ret = 0;
1233 for (i = 0; i < nstripes; ++i) {
1234 /*
1235 * canceled?
1236 */
1237 if (atomic_read(&fs_info->scrub_cancel_req) ||
1238 atomic_read(&sdev->cancel_req)) {
1239 ret = -ECANCELED;
1240 goto out;
1241 }
1242 /*
1243 * check to see if we have to pause
1244 */
1245 if (atomic_read(&fs_info->scrub_pause_req)) {
1246 /* push queued extents */
1247 scrub_submit(sdev);
1248 wait_event(sdev->list_wait,
1249 atomic_read(&sdev->in_flight) == 0);
1250 atomic_inc(&fs_info->scrubs_paused);
1251 wake_up(&fs_info->scrub_pause_wait);
1252 mutex_lock(&fs_info->scrub_lock);
1253 while (atomic_read(&fs_info->scrub_pause_req)) {
1254 mutex_unlock(&fs_info->scrub_lock);
1255 wait_event(fs_info->scrub_pause_wait,
1256 atomic_read(&fs_info->scrub_pause_req) == 0);
1257 mutex_lock(&fs_info->scrub_lock);
1258 }
1259 atomic_dec(&fs_info->scrubs_paused);
1260 mutex_unlock(&fs_info->scrub_lock);
1261 wake_up(&fs_info->scrub_pause_wait);
1262 }
1263
1264 ret = btrfs_lookup_csums_range(csum_root, logical,
1265 logical + map->stripe_len - 1,
1266 &sdev->csum_list, 1);
1267 if (ret)
1268 goto out;
1269
1270 key.objectid = logical;
1271 key.type = BTRFS_EXTENT_ITEM_KEY;
1272 key.offset = (u64)0;
1273
1274 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1275 if (ret < 0)
1276 goto out;
1277 if (ret > 0) {
1278 ret = btrfs_previous_item(root, path, 0,
1279 BTRFS_EXTENT_ITEM_KEY);
1280 if (ret < 0)
1281 goto out;
1282 if (ret > 0) {
1283 /* there's no smaller item, so stick with the
1284 * larger one */
1285 btrfs_release_path(path);
1286 ret = btrfs_search_slot(NULL, root, &key,
1287 path, 0, 0);
1288 if (ret < 0)
1289 goto out;
1290 }
1291 }
1292
1293 while (1) {
1294 l = path->nodes[0];
1295 slot = path->slots[0];
1296 if (slot >= btrfs_header_nritems(l)) {
1297 ret = btrfs_next_leaf(root, path);
1298 if (ret == 0)
1299 continue;
1300 if (ret < 0)
1301 goto out;
1302
1303 break;
1304 }
1305 btrfs_item_key_to_cpu(l, &key, slot);
1306
1307 if (key.objectid + key.offset <= logical)
1308 goto next;
1309
1310 if (key.objectid >= logical + map->stripe_len)
1311 break;
1312
1313 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY)
1314 goto next;
1315
1316 extent = btrfs_item_ptr(l, slot,
1317 struct btrfs_extent_item);
1318 flags = btrfs_extent_flags(l, extent);
1319 generation = btrfs_extent_generation(l, extent);
1320
1321 if (key.objectid < logical &&
1322 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) {
1323 printk(KERN_ERR
1324 "btrfs scrub: tree block %llu spanning "
1325 "stripes, ignored. logical=%llu\n",
1326 (unsigned long long)key.objectid,
1327 (unsigned long long)logical);
1328 goto next;
1329 }
1330
1331 /*
1332 * trim extent to this stripe
1333 */
1334 if (key.objectid < logical) {
1335 key.offset -= logical - key.objectid;
1336 key.objectid = logical;
1337 }
1338 if (key.objectid + key.offset >
1339 logical + map->stripe_len) {
1340 key.offset = logical + map->stripe_len -
1341 key.objectid;
1342 }
1343
1344 ret = scrub_extent(sdev, key.objectid, key.offset,
1345 key.objectid - logical + physical,
1346 flags, generation, mirror_num);
1347 if (ret)
1348 goto out;
1349
1350 next:
1351 path->slots[0]++;
1352 }
1353 btrfs_release_path(path);
1354 logical += increment;
1355 physical += map->stripe_len;
1356 spin_lock(&sdev->stat_lock);
1357 sdev->stat.last_physical = physical;
1358 spin_unlock(&sdev->stat_lock);
1359 }
1360 /* push queued extents */
1361 scrub_submit(sdev);
1362
1363 out:
1364 blk_finish_plug(&plug);
1365 btrfs_free_path(path);
1366 return ret < 0 ? ret : 0;
1367 }
1368
1369 static noinline_for_stack int scrub_chunk(struct scrub_dev *sdev,
1370 u64 chunk_tree, u64 chunk_objectid, u64 chunk_offset, u64 length,
1371 u64 dev_offset)
1372 {
1373 struct btrfs_mapping_tree *map_tree =
1374 &sdev->dev->dev_root->fs_info->mapping_tree;
1375 struct map_lookup *map;
1376 struct extent_map *em;
1377 int i;
1378 int ret = -EINVAL;
1379
1380 read_lock(&map_tree->map_tree.lock);
1381 em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
1382 read_unlock(&map_tree->map_tree.lock);
1383
1384 if (!em)
1385 return -EINVAL;
1386
1387 map = (struct map_lookup *)em->bdev;
1388 if (em->start != chunk_offset)
1389 goto out;
1390
1391 if (em->len < length)
1392 goto out;
1393
1394 for (i = 0; i < map->num_stripes; ++i) {
1395 if (map->stripes[i].dev == sdev->dev &&
1396 map->stripes[i].physical == dev_offset) {
1397 ret = scrub_stripe(sdev, map, i, chunk_offset, length);
1398 if (ret)
1399 goto out;
1400 }
1401 }
1402 out:
1403 free_extent_map(em);
1404
1405 return ret;
1406 }
1407
1408 static noinline_for_stack
1409 int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end)
1410 {
1411 struct btrfs_dev_extent *dev_extent = NULL;
1412 struct btrfs_path *path;
1413 struct btrfs_root *root = sdev->dev->dev_root;
1414 struct btrfs_fs_info *fs_info = root->fs_info;
1415 u64 length;
1416 u64 chunk_tree;
1417 u64 chunk_objectid;
1418 u64 chunk_offset;
1419 int ret;
1420 int slot;
1421 struct extent_buffer *l;
1422 struct btrfs_key key;
1423 struct btrfs_key found_key;
1424 struct btrfs_block_group_cache *cache;
1425
1426 path = btrfs_alloc_path();
1427 if (!path)
1428 return -ENOMEM;
1429
1430 path->reada = 2;
1431 path->search_commit_root = 1;
1432 path->skip_locking = 1;
1433
1434 key.objectid = sdev->dev->devid;
1435 key.offset = 0ull;
1436 key.type = BTRFS_DEV_EXTENT_KEY;
1437
1438
1439 while (1) {
1440 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1441 if (ret < 0)
1442 break;
1443 if (ret > 0) {
1444 if (path->slots[0] >=
1445 btrfs_header_nritems(path->nodes[0])) {
1446 ret = btrfs_next_leaf(root, path);
1447 if (ret)
1448 break;
1449 }
1450 }
1451
1452 l = path->nodes[0];
1453 slot = path->slots[0];
1454
1455 btrfs_item_key_to_cpu(l, &found_key, slot);
1456
1457 if (found_key.objectid != sdev->dev->devid)
1458 break;
1459
1460 if (btrfs_key_type(&found_key) != BTRFS_DEV_EXTENT_KEY)
1461 break;
1462
1463 if (found_key.offset >= end)
1464 break;
1465
1466 if (found_key.offset < key.offset)
1467 break;
1468
1469 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1470 length = btrfs_dev_extent_length(l, dev_extent);
1471
1472 if (found_key.offset + length <= start) {
1473 key.offset = found_key.offset + length;
1474 btrfs_release_path(path);
1475 continue;
1476 }
1477
1478 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
1479 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
1480 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
1481
1482 /*
1483 * get a reference on the corresponding block group to prevent
1484 * the chunk from going away while we scrub it
1485 */
1486 cache = btrfs_lookup_block_group(fs_info, chunk_offset);
1487 if (!cache) {
1488 ret = -ENOENT;
1489 break;
1490 }
1491 ret = scrub_chunk(sdev, chunk_tree, chunk_objectid,
1492 chunk_offset, length, found_key.offset);
1493 btrfs_put_block_group(cache);
1494 if (ret)
1495 break;
1496
1497 key.offset = found_key.offset + length;
1498 btrfs_release_path(path);
1499 }
1500
1501 btrfs_free_path(path);
1502
1503 /*
1504 * ret can still be 1 from search_slot or next_leaf,
1505 * that's not an error
1506 */
1507 return ret < 0 ? ret : 0;
1508 }
1509
1510 static noinline_for_stack int scrub_supers(struct scrub_dev *sdev)
1511 {
1512 int i;
1513 u64 bytenr;
1514 u64 gen;
1515 int ret;
1516 struct btrfs_device *device = sdev->dev;
1517 struct btrfs_root *root = device->dev_root;
1518
1519 gen = root->fs_info->last_trans_committed;
1520
1521 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
1522 bytenr = btrfs_sb_offset(i);
1523 if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
1524 break;
1525
1526 ret = scrub_page(sdev, bytenr, PAGE_SIZE, bytenr,
1527 BTRFS_EXTENT_FLAG_SUPER, gen, i, NULL, 1);
1528 if (ret)
1529 return ret;
1530 }
1531 wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
1532
1533 return 0;
1534 }
1535
1536 /*
1537 * get a reference count on fs_info->scrub_workers. start worker if necessary
1538 */
1539 static noinline_for_stack int scrub_workers_get(struct btrfs_root *root)
1540 {
1541 struct btrfs_fs_info *fs_info = root->fs_info;
1542 int ret = 0;
1543
1544 mutex_lock(&fs_info->scrub_lock);
1545 if (fs_info->scrub_workers_refcnt == 0) {
1546 btrfs_init_workers(&fs_info->scrub_workers, "scrub",
1547 fs_info->thread_pool_size, &fs_info->generic_worker);
1548 fs_info->scrub_workers.idle_thresh = 4;
1549 ret = btrfs_start_workers(&fs_info->scrub_workers);
1550 if (ret)
1551 goto out;
1552 }
1553 ++fs_info->scrub_workers_refcnt;
1554 out:
1555 mutex_unlock(&fs_info->scrub_lock);
1556
1557 return ret;
1558 }
1559
1560 static noinline_for_stack void scrub_workers_put(struct btrfs_root *root)
1561 {
1562 struct btrfs_fs_info *fs_info = root->fs_info;
1563
1564 mutex_lock(&fs_info->scrub_lock);
1565 if (--fs_info->scrub_workers_refcnt == 0)
1566 btrfs_stop_workers(&fs_info->scrub_workers);
1567 WARN_ON(fs_info->scrub_workers_refcnt < 0);
1568 mutex_unlock(&fs_info->scrub_lock);
1569 }
1570
1571
1572 int btrfs_scrub_dev(struct btrfs_root *root, u64 devid, u64 start, u64 end,
1573 struct btrfs_scrub_progress *progress, int readonly)
1574 {
1575 struct scrub_dev *sdev;
1576 struct btrfs_fs_info *fs_info = root->fs_info;
1577 int ret;
1578 struct btrfs_device *dev;
1579
1580 if (btrfs_fs_closing(root->fs_info))
1581 return -EINVAL;
1582
1583 /*
1584 * check some assumptions
1585 */
1586 if (root->sectorsize != PAGE_SIZE ||
1587 root->sectorsize != root->leafsize ||
1588 root->sectorsize != root->nodesize) {
1589 printk(KERN_ERR "btrfs_scrub: size assumptions fail\n");
1590 return -EINVAL;
1591 }
1592
1593 ret = scrub_workers_get(root);
1594 if (ret)
1595 return ret;
1596
1597 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1598 dev = btrfs_find_device(root, devid, NULL, NULL);
1599 if (!dev || dev->missing) {
1600 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1601 scrub_workers_put(root);
1602 return -ENODEV;
1603 }
1604 mutex_lock(&fs_info->scrub_lock);
1605
1606 if (!dev->in_fs_metadata) {
1607 mutex_unlock(&fs_info->scrub_lock);
1608 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1609 scrub_workers_put(root);
1610 return -ENODEV;
1611 }
1612
1613 if (dev->scrub_device) {
1614 mutex_unlock(&fs_info->scrub_lock);
1615 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1616 scrub_workers_put(root);
1617 return -EINPROGRESS;
1618 }
1619 sdev = scrub_setup_dev(dev);
1620 if (IS_ERR(sdev)) {
1621 mutex_unlock(&fs_info->scrub_lock);
1622 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1623 scrub_workers_put(root);
1624 return PTR_ERR(sdev);
1625 }
1626 sdev->readonly = readonly;
1627 dev->scrub_device = sdev;
1628
1629 atomic_inc(&fs_info->scrubs_running);
1630 mutex_unlock(&fs_info->scrub_lock);
1631 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1632
1633 down_read(&fs_info->scrub_super_lock);
1634 ret = scrub_supers(sdev);
1635 up_read(&fs_info->scrub_super_lock);
1636
1637 if (!ret)
1638 ret = scrub_enumerate_chunks(sdev, start, end);
1639
1640 wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
1641 atomic_dec(&fs_info->scrubs_running);
1642 wake_up(&fs_info->scrub_pause_wait);
1643
1644 wait_event(sdev->list_wait, atomic_read(&sdev->fixup_cnt) == 0);
1645
1646 if (progress)
1647 memcpy(progress, &sdev->stat, sizeof(*progress));
1648
1649 mutex_lock(&fs_info->scrub_lock);
1650 dev->scrub_device = NULL;
1651 mutex_unlock(&fs_info->scrub_lock);
1652
1653 scrub_free_dev(sdev);
1654 scrub_workers_put(root);
1655
1656 return ret;
1657 }
1658
1659 int btrfs_scrub_pause(struct btrfs_root *root)
1660 {
1661 struct btrfs_fs_info *fs_info = root->fs_info;
1662
1663 mutex_lock(&fs_info->scrub_lock);
1664 atomic_inc(&fs_info->scrub_pause_req);
1665 while (atomic_read(&fs_info->scrubs_paused) !=
1666 atomic_read(&fs_info->scrubs_running)) {
1667 mutex_unlock(&fs_info->scrub_lock);
1668 wait_event(fs_info->scrub_pause_wait,
1669 atomic_read(&fs_info->scrubs_paused) ==
1670 atomic_read(&fs_info->scrubs_running));
1671 mutex_lock(&fs_info->scrub_lock);
1672 }
1673 mutex_unlock(&fs_info->scrub_lock);
1674
1675 return 0;
1676 }
1677
1678 int btrfs_scrub_continue(struct btrfs_root *root)
1679 {
1680 struct btrfs_fs_info *fs_info = root->fs_info;
1681
1682 atomic_dec(&fs_info->scrub_pause_req);
1683 wake_up(&fs_info->scrub_pause_wait);
1684 return 0;
1685 }
1686
1687 int btrfs_scrub_pause_super(struct btrfs_root *root)
1688 {
1689 down_write(&root->fs_info->scrub_super_lock);
1690 return 0;
1691 }
1692
1693 int btrfs_scrub_continue_super(struct btrfs_root *root)
1694 {
1695 up_write(&root->fs_info->scrub_super_lock);
1696 return 0;
1697 }
1698
1699 int btrfs_scrub_cancel(struct btrfs_root *root)
1700 {
1701 struct btrfs_fs_info *fs_info = root->fs_info;
1702
1703 mutex_lock(&fs_info->scrub_lock);
1704 if (!atomic_read(&fs_info->scrubs_running)) {
1705 mutex_unlock(&fs_info->scrub_lock);
1706 return -ENOTCONN;
1707 }
1708
1709 atomic_inc(&fs_info->scrub_cancel_req);
1710 while (atomic_read(&fs_info->scrubs_running)) {
1711 mutex_unlock(&fs_info->scrub_lock);
1712 wait_event(fs_info->scrub_pause_wait,
1713 atomic_read(&fs_info->scrubs_running) == 0);
1714 mutex_lock(&fs_info->scrub_lock);
1715 }
1716 atomic_dec(&fs_info->scrub_cancel_req);
1717 mutex_unlock(&fs_info->scrub_lock);
1718
1719 return 0;
1720 }
1721
1722 int btrfs_scrub_cancel_dev(struct btrfs_root *root, struct btrfs_device *dev)
1723 {
1724 struct btrfs_fs_info *fs_info = root->fs_info;
1725 struct scrub_dev *sdev;
1726
1727 mutex_lock(&fs_info->scrub_lock);
1728 sdev = dev->scrub_device;
1729 if (!sdev) {
1730 mutex_unlock(&fs_info->scrub_lock);
1731 return -ENOTCONN;
1732 }
1733 atomic_inc(&sdev->cancel_req);
1734 while (dev->scrub_device) {
1735 mutex_unlock(&fs_info->scrub_lock);
1736 wait_event(fs_info->scrub_pause_wait,
1737 dev->scrub_device == NULL);
1738 mutex_lock(&fs_info->scrub_lock);
1739 }
1740 mutex_unlock(&fs_info->scrub_lock);
1741
1742 return 0;
1743 }
1744 int btrfs_scrub_cancel_devid(struct btrfs_root *root, u64 devid)
1745 {
1746 struct btrfs_fs_info *fs_info = root->fs_info;
1747 struct btrfs_device *dev;
1748 int ret;
1749
1750 /*
1751 * we have to hold the device_list_mutex here so the device
1752 * does not go away in cancel_dev. FIXME: find a better solution
1753 */
1754 mutex_lock(&fs_info->fs_devices->device_list_mutex);
1755 dev = btrfs_find_device(root, devid, NULL, NULL);
1756 if (!dev) {
1757 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1758 return -ENODEV;
1759 }
1760 ret = btrfs_scrub_cancel_dev(root, dev);
1761 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1762
1763 return ret;
1764 }
1765
1766 int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
1767 struct btrfs_scrub_progress *progress)
1768 {
1769 struct btrfs_device *dev;
1770 struct scrub_dev *sdev = NULL;
1771
1772 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1773 dev = btrfs_find_device(root, devid, NULL, NULL);
1774 if (dev)
1775 sdev = dev->scrub_device;
1776 if (sdev)
1777 memcpy(progress, &sdev->stat, sizeof(*progress));
1778 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1779
1780 return dev ? (sdev ? 0 : -ENOTCONN) : -ENODEV;
1781 }