?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Add linux-next specific files for 20110716
[linux-2.6/next.git] / fs / btrfs / scrub.c
bloba8d03d5efb5df3b3a8d4f6fa659909e571a69a7c
1 /*
2 * Copyright (C) 2011 STRATO. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/blkdev.h>
20 #include "ctree.h"
21 #include "volumes.h"
22 #include "disk-io.h"
23 #include "ordered-data.h"
24
25 /*
26 * This is only the first step towards a full-features scrub. It reads all
27 * extent and super block and verifies the checksums. In case a bad checksum
28 * is found or the extent cannot be read, good data will be written back if
29 * any can be found.
30 *
31 * Future enhancements:
32 * - To enhance the performance, better read-ahead strategies for the
33 * extent-tree can be employed.
34 * - In case an unrepairable extent is encountered, track which files are
35 * affected and report them
36 * - In case of a read error on files with nodatasum, map the file and read
37 * the extent to trigger a writeback of the good copy
38 * - track and record media errors, throw out bad devices
39 * - add a mode to also read unallocated space
40 * - make the prefetch cancellable
41 */
42
43 struct scrub_bio;
44 struct scrub_page;
45 struct scrub_dev;
46 static void scrub_bio_end_io(struct bio *bio, int err);
47 static void scrub_checksum(struct btrfs_work *work);
48 static int scrub_checksum_data(struct scrub_dev *sdev,
49 struct scrub_page *spag, void *buffer);
50 static int scrub_checksum_tree_block(struct scrub_dev *sdev,
51 struct scrub_page *spag, u64 logical,
52 void *buffer);
53 static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer);
54 static int scrub_fixup_check(struct scrub_bio *sbio, int ix);
55 static void scrub_fixup_end_io(struct bio *bio, int err);
56 static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector,
57 struct page *page);
58 static void scrub_fixup(struct scrub_bio *sbio, int ix);
59
60 #define SCRUB_PAGES_PER_BIO 16 /* 64k per bio */
61 #define SCRUB_BIOS_PER_DEV 16 /* 1 MB per device in flight */
62
63 struct scrub_page {
64 u64 flags; /* extent flags */
65 u64 generation;
66 u64 mirror_num;
67 int have_csum;
68 u8 csum[BTRFS_CSUM_SIZE];
69 };
70
71 struct scrub_bio {
72 int index;
73 struct scrub_dev *sdev;
74 struct bio *bio;
75 int err;
76 u64 logical;
77 u64 physical;
78 struct scrub_page spag[SCRUB_PAGES_PER_BIO];
79 u64 count;
80 int next_free;
81 struct btrfs_work work;
82 };
83
84 struct scrub_dev {
85 struct scrub_bio *bios[SCRUB_BIOS_PER_DEV];
86 struct btrfs_device *dev;
87 int first_free;
88 int curr;
89 atomic_t in_flight;
90 spinlock_t list_lock;
91 wait_queue_head_t list_wait;
92 u16 csum_size;
93 struct list_head csum_list;
94 atomic_t cancel_req;
95 int readonly;
96 /*
97 * statistics
98 */
99 struct btrfs_scrub_progress stat;
100 spinlock_t stat_lock;
101 };
102
103 static void scrub_free_csums(struct scrub_dev *sdev)
104 {
105 while (!list_empty(&sdev->csum_list)) {
106 struct btrfs_ordered_sum *sum;
107 sum = list_first_entry(&sdev->csum_list,
108 struct btrfs_ordered_sum, list);
109 list_del(&sum->list);
110 kfree(sum);
111 }
112 }
113
114 static void scrub_free_bio(struct bio *bio)
115 {
116 int i;
117 struct page *last_page = NULL;
118
119 if (!bio)
120 return;
121
122 for (i = 0; i < bio->bi_vcnt; ++i) {
123 if (bio->bi_io_vec[i].bv_page == last_page)
124 continue;
125 last_page = bio->bi_io_vec[i].bv_page;
126 __free_page(last_page);
127 }
128 bio_put(bio);
129 }
130
131 static noinline_for_stack void scrub_free_dev(struct scrub_dev *sdev)
132 {
133 int i;
134
135 if (!sdev)
136 return;
137
138 for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
139 struct scrub_bio *sbio = sdev->bios[i];
140
141 if (!sbio)
142 break;
143
144 scrub_free_bio(sbio->bio);
145 kfree(sbio);
146 }
147
148 scrub_free_csums(sdev);
149 kfree(sdev);
150 }
151
152 static noinline_for_stack
153 struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev)
154 {
155 struct scrub_dev *sdev;
156 int i;
157 struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
158
159 sdev = kzalloc(sizeof(*sdev), GFP_NOFS);
160 if (!sdev)
161 goto nomem;
162 sdev->dev = dev;
163 for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
164 struct scrub_bio *sbio;
165
166 sbio = kzalloc(sizeof(*sbio), GFP_NOFS);
167 if (!sbio)
168 goto nomem;
169 sdev->bios[i] = sbio;
170
171 sbio->index = i;
172 sbio->sdev = sdev;
173 sbio->count = 0;
174 sbio->work.func = scrub_checksum;
175
176 if (i != SCRUB_BIOS_PER_DEV-1)
177 sdev->bios[i]->next_free = i + 1;
178 else
179 sdev->bios[i]->next_free = -1;
180 }
181 sdev->first_free = 0;
182 sdev->curr = -1;
183 atomic_set(&sdev->in_flight, 0);
184 atomic_set(&sdev->cancel_req, 0);
185 sdev->csum_size = btrfs_super_csum_size(&fs_info->super_copy);
186 INIT_LIST_HEAD(&sdev->csum_list);
187
188 spin_lock_init(&sdev->list_lock);
189 spin_lock_init(&sdev->stat_lock);
190 init_waitqueue_head(&sdev->list_wait);
191 return sdev;
192
193 nomem:
194 scrub_free_dev(sdev);
195 return ERR_PTR(-ENOMEM);
196 }
197
198 /*
199 * scrub_recheck_error gets called when either verification of the page
200 * failed or the bio failed to read, e.g. with EIO. In the latter case,
201 * recheck_error gets called for every page in the bio, even though only
202 * one may be bad
203 */
204 static void scrub_recheck_error(struct scrub_bio *sbio, int ix)
205 {
206 if (sbio->err) {
207 if (scrub_fixup_io(READ, sbio->sdev->dev->bdev,
208 (sbio->physical + ix * PAGE_SIZE) >> 9,
209 sbio->bio->bi_io_vec[ix].bv_page) == 0) {
210 if (scrub_fixup_check(sbio, ix) == 0)
211 return;
212 }
213 }
214
215 scrub_fixup(sbio, ix);
216 }
217
218 static int scrub_fixup_check(struct scrub_bio *sbio, int ix)
219 {
220 int ret = 1;
221 struct page *page;
222 void *buffer;
223 u64 flags = sbio->spag[ix].flags;
224
225 page = sbio->bio->bi_io_vec[ix].bv_page;
226 buffer = kmap_atomic(page, KM_USER0);
227 if (flags & BTRFS_EXTENT_FLAG_DATA) {
228 ret = scrub_checksum_data(sbio->sdev,
229 sbio->spag + ix, buffer);
230 } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
231 ret = scrub_checksum_tree_block(sbio->sdev,
232 sbio->spag + ix,
233 sbio->logical + ix * PAGE_SIZE,
234 buffer);
235 } else {
236 WARN_ON(1);
237 }
238 kunmap_atomic(buffer, KM_USER0);
239
240 return ret;
241 }
242
243 static void scrub_fixup_end_io(struct bio *bio, int err)
244 {
245 complete((struct completion *)bio->bi_private);
246 }
247
248 static void scrub_fixup(struct scrub_bio *sbio, int ix)
249 {
250 struct scrub_dev *sdev = sbio->sdev;
251 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
252 struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
253 struct btrfs_multi_bio *multi = NULL;
254 u64 logical = sbio->logical + ix * PAGE_SIZE;
255 u64 length;
256 int i;
257 int ret;
258 DECLARE_COMPLETION_ONSTACK(complete);
259
260 if ((sbio->spag[ix].flags & BTRFS_EXTENT_FLAG_DATA) &&
261 (sbio->spag[ix].have_csum == 0)) {
262 /*
263 * nodatasum, don't try to fix anything
264 * FIXME: we can do better, open the inode and trigger a
265 * writeback
266 */
267 goto uncorrectable;
268 }
269
270 length = PAGE_SIZE;
271 ret = btrfs_map_block(map_tree, REQ_WRITE, logical, &length,
272 &multi, 0);
273 if (ret || !multi || length < PAGE_SIZE) {
274 printk(KERN_ERR
275 "scrub_fixup: btrfs_map_block failed us for %llu\n",
276 (unsigned long long)logical);
277 WARN_ON(1);
278 return;
279 }
280
281 if (multi->num_stripes == 1)
282 /* there aren't any replicas */
283 goto uncorrectable;
284
285 /*
286 * first find a good copy
287 */
288 for (i = 0; i < multi->num_stripes; ++i) {
289 if (i == sbio->spag[ix].mirror_num)
290 continue;
291
292 if (scrub_fixup_io(READ, multi->stripes[i].dev->bdev,
293 multi->stripes[i].physical >> 9,
294 sbio->bio->bi_io_vec[ix].bv_page)) {
295 /* I/O-error, this is not a good copy */
296 continue;
297 }
298
299 if (scrub_fixup_check(sbio, ix) == 0)
300 break;
301 }
302 if (i == multi->num_stripes)
303 goto uncorrectable;
304
305 if (!sdev->readonly) {
306 /*
307 * bi_io_vec[ix].bv_page now contains good data, write it back
308 */
309 if (scrub_fixup_io(WRITE, sdev->dev->bdev,
310 (sbio->physical + ix * PAGE_SIZE) >> 9,
311 sbio->bio->bi_io_vec[ix].bv_page)) {
312 /* I/O-error, writeback failed, give up */
313 goto uncorrectable;
314 }
315 }
316
317 kfree(multi);
318 spin_lock(&sdev->stat_lock);
319 ++sdev->stat.corrected_errors;
320 spin_unlock(&sdev->stat_lock);
321
322 if (printk_ratelimit())
323 printk(KERN_ERR "btrfs: fixed up at %llu\n",
324 (unsigned long long)logical);
325 return;
326
327 uncorrectable:
328 kfree(multi);
329 spin_lock(&sdev->stat_lock);
330 ++sdev->stat.uncorrectable_errors;
331 spin_unlock(&sdev->stat_lock);
332
333 if (printk_ratelimit())
334 printk(KERN_ERR "btrfs: unable to fixup at %llu\n",
335 (unsigned long long)logical);
336 }
337
338 static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector,
339 struct page *page)
340 {
341 struct bio *bio = NULL;
342 int ret;
343 DECLARE_COMPLETION_ONSTACK(complete);
344
345 bio = bio_alloc(GFP_NOFS, 1);
346 bio->bi_bdev = bdev;
347 bio->bi_sector = sector;
348 bio_add_page(bio, page, PAGE_SIZE, 0);
349 bio->bi_end_io = scrub_fixup_end_io;
350 bio->bi_private = &complete;
351 submit_bio(rw, bio);
352
353 /* this will also unplug the queue */
354 wait_for_completion(&complete);
355
356 ret = !test_bit(BIO_UPTODATE, &bio->bi_flags);
357 bio_put(bio);
358 return ret;
359 }
360
361 static void scrub_bio_end_io(struct bio *bio, int err)
362 {
363 struct scrub_bio *sbio = bio->bi_private;
364 struct scrub_dev *sdev = sbio->sdev;
365 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
366
367 sbio->err = err;
368 sbio->bio = bio;
369
370 btrfs_queue_worker(&fs_info->scrub_workers, &sbio->work);
371 }
372
373 static void scrub_checksum(struct btrfs_work *work)
374 {
375 struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
376 struct scrub_dev *sdev = sbio->sdev;
377 struct page *page;
378 void *buffer;
379 int i;
380 u64 flags;
381 u64 logical;
382 int ret;
383
384 if (sbio->err) {
385 for (i = 0; i < sbio->count; ++i)
386 scrub_recheck_error(sbio, i);
387
388 sbio->bio->bi_flags &= ~(BIO_POOL_MASK - 1);
389 sbio->bio->bi_flags |= 1 << BIO_UPTODATE;
390 sbio->bio->bi_phys_segments = 0;
391 sbio->bio->bi_idx = 0;
392
393 for (i = 0; i < sbio->count; i++) {
394 struct bio_vec *bi;
395 bi = &sbio->bio->bi_io_vec[i];
396 bi->bv_offset = 0;
397 bi->bv_len = PAGE_SIZE;
398 }
399
400 spin_lock(&sdev->stat_lock);
401 ++sdev->stat.read_errors;
402 spin_unlock(&sdev->stat_lock);
403 goto out;
404 }
405 for (i = 0; i < sbio->count; ++i) {
406 page = sbio->bio->bi_io_vec[i].bv_page;
407 buffer = kmap_atomic(page, KM_USER0);
408 flags = sbio->spag[i].flags;
409 logical = sbio->logical + i * PAGE_SIZE;
410 ret = 0;
411 if (flags & BTRFS_EXTENT_FLAG_DATA) {
412 ret = scrub_checksum_data(sdev, sbio->spag + i, buffer);
413 } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
414 ret = scrub_checksum_tree_block(sdev, sbio->spag + i,
415 logical, buffer);
416 } else if (flags & BTRFS_EXTENT_FLAG_SUPER) {
417 BUG_ON(i);
418 (void)scrub_checksum_super(sbio, buffer);
419 } else {
420 WARN_ON(1);
421 }
422 kunmap_atomic(buffer, KM_USER0);
423 if (ret)
424 scrub_recheck_error(sbio, i);
425 }
426
427 out:
428 scrub_free_bio(sbio->bio);
429 sbio->bio = NULL;
430 spin_lock(&sdev->list_lock);
431 sbio->next_free = sdev->first_free;
432 sdev->first_free = sbio->index;
433 spin_unlock(&sdev->list_lock);
434 atomic_dec(&sdev->in_flight);
435 wake_up(&sdev->list_wait);
436 }
437
438 static int scrub_checksum_data(struct scrub_dev *sdev,
439 struct scrub_page *spag, void *buffer)
440 {
441 u8 csum[BTRFS_CSUM_SIZE];
442 u32 crc = ~(u32)0;
443 int fail = 0;
444 struct btrfs_root *root = sdev->dev->dev_root;
445
446 if (!spag->have_csum)
447 return 0;
448
449 crc = btrfs_csum_data(root, buffer, crc, PAGE_SIZE);
450 btrfs_csum_final(crc, csum);
451 if (memcmp(csum, spag->csum, sdev->csum_size))
452 fail = 1;
453
454 spin_lock(&sdev->stat_lock);
455 ++sdev->stat.data_extents_scrubbed;
456 sdev->stat.data_bytes_scrubbed += PAGE_SIZE;
457 if (fail)
458 ++sdev->stat.csum_errors;
459 spin_unlock(&sdev->stat_lock);
460
461 return fail;
462 }
463
464 static int scrub_checksum_tree_block(struct scrub_dev *sdev,
465 struct scrub_page *spag, u64 logical,
466 void *buffer)
467 {
468 struct btrfs_header *h;
469 struct btrfs_root *root = sdev->dev->dev_root;
470 struct btrfs_fs_info *fs_info = root->fs_info;
471 u8 csum[BTRFS_CSUM_SIZE];
472 u32 crc = ~(u32)0;
473 int fail = 0;
474 int crc_fail = 0;
475
476 /*
477 * we don't use the getter functions here, as we
478 * a) don't have an extent buffer and
479 * b) the page is already kmapped
480 */
481 h = (struct btrfs_header *)buffer;
482
483 if (logical != le64_to_cpu(h->bytenr))
484 ++fail;
485
486 if (spag->generation != le64_to_cpu(h->generation))
487 ++fail;
488
489 if (memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
490 ++fail;
491
492 if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
493 BTRFS_UUID_SIZE))
494 ++fail;
495
496 crc = btrfs_csum_data(root, buffer + BTRFS_CSUM_SIZE, crc,
497 PAGE_SIZE - BTRFS_CSUM_SIZE);
498 btrfs_csum_final(crc, csum);
499 if (memcmp(csum, h->csum, sdev->csum_size))
500 ++crc_fail;
501
502 spin_lock(&sdev->stat_lock);
503 ++sdev->stat.tree_extents_scrubbed;
504 sdev->stat.tree_bytes_scrubbed += PAGE_SIZE;
505 if (crc_fail)
506 ++sdev->stat.csum_errors;
507 if (fail)
508 ++sdev->stat.verify_errors;
509 spin_unlock(&sdev->stat_lock);
510
511 return fail || crc_fail;
512 }
513
514 static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer)
515 {
516 struct btrfs_super_block *s;
517 u64 logical;
518 struct scrub_dev *sdev = sbio->sdev;
519 struct btrfs_root *root = sdev->dev->dev_root;
520 struct btrfs_fs_info *fs_info = root->fs_info;
521 u8 csum[BTRFS_CSUM_SIZE];
522 u32 crc = ~(u32)0;
523 int fail = 0;
524
525 s = (struct btrfs_super_block *)buffer;
526 logical = sbio->logical;
527
528 if (logical != le64_to_cpu(s->bytenr))
529 ++fail;
530
531 if (sbio->spag[0].generation != le64_to_cpu(s->generation))
532 ++fail;
533
534 if (memcmp(s->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
535 ++fail;
536
537 crc = btrfs_csum_data(root, buffer + BTRFS_CSUM_SIZE, crc,
538 PAGE_SIZE - BTRFS_CSUM_SIZE);
539 btrfs_csum_final(crc, csum);
540 if (memcmp(csum, s->csum, sbio->sdev->csum_size))
541 ++fail;
542
543 if (fail) {
544 /*
545 * if we find an error in a super block, we just report it.
546 * They will get written with the next transaction commit
547 * anyway
548 */
549 spin_lock(&sdev->stat_lock);
550 ++sdev->stat.super_errors;
551 spin_unlock(&sdev->stat_lock);
552 }
553
554 return fail;
555 }
556
557 static int scrub_submit(struct scrub_dev *sdev)
558 {
559 struct scrub_bio *sbio;
560 struct bio *bio;
561 int i;
562
563 if (sdev->curr == -1)
564 return 0;
565
566 sbio = sdev->bios[sdev->curr];
567
568 bio = bio_alloc(GFP_NOFS, sbio->count);
569 if (!bio)
570 goto nomem;
571
572 bio->bi_private = sbio;
573 bio->bi_end_io = scrub_bio_end_io;
574 bio->bi_bdev = sdev->dev->bdev;
575 bio->bi_sector = sbio->physical >> 9;
576
577 for (i = 0; i < sbio->count; ++i) {
578 struct page *page;
579 int ret;
580
581 page = alloc_page(GFP_NOFS);
582 if (!page)
583 goto nomem;
584
585 ret = bio_add_page(bio, page, PAGE_SIZE, 0);
586 if (!ret) {
587 __free_page(page);
588 goto nomem;
589 }
590 }
591
592 sbio->err = 0;
593 sdev->curr = -1;
594 atomic_inc(&sdev->in_flight);
595
596 submit_bio(READ, bio);
597
598 return 0;
599
600 nomem:
601 scrub_free_bio(bio);
602
603 return -ENOMEM;
604 }
605
606 static int scrub_page(struct scrub_dev *sdev, u64 logical, u64 len,
607 u64 physical, u64 flags, u64 gen, u64 mirror_num,
608 u8 *csum, int force)
609 {
610 struct scrub_bio *sbio;
611
612 again:
613 /*
614 * grab a fresh bio or wait for one to become available
615 */
616 while (sdev->curr == -1) {
617 spin_lock(&sdev->list_lock);
618 sdev->curr = sdev->first_free;
619 if (sdev->curr != -1) {
620 sdev->first_free = sdev->bios[sdev->curr]->next_free;
621 sdev->bios[sdev->curr]->next_free = -1;
622 sdev->bios[sdev->curr]->count = 0;
623 spin_unlock(&sdev->list_lock);
624 } else {
625 spin_unlock(&sdev->list_lock);
626 wait_event(sdev->list_wait, sdev->first_free != -1);
627 }
628 }
629 sbio = sdev->bios[sdev->curr];
630 if (sbio->count == 0) {
631 sbio->physical = physical;
632 sbio->logical = logical;
633 } else if (sbio->physical + sbio->count * PAGE_SIZE != physical ||
634 sbio->logical + sbio->count * PAGE_SIZE != logical) {
635 int ret;
636
637 ret = scrub_submit(sdev);
638 if (ret)
639 return ret;
640 goto again;
641 }
642 sbio->spag[sbio->count].flags = flags;
643 sbio->spag[sbio->count].generation = gen;
644 sbio->spag[sbio->count].have_csum = 0;
645 sbio->spag[sbio->count].mirror_num = mirror_num;
646 if (csum) {
647 sbio->spag[sbio->count].have_csum = 1;
648 memcpy(sbio->spag[sbio->count].csum, csum, sdev->csum_size);
649 }
650 ++sbio->count;
651 if (sbio->count == SCRUB_PAGES_PER_BIO || force) {
652 int ret;
653
654 ret = scrub_submit(sdev);
655 if (ret)
656 return ret;
657 }
658
659 return 0;
660 }
661
662 static int scrub_find_csum(struct scrub_dev *sdev, u64 logical, u64 len,
663 u8 *csum)
664 {
665 struct btrfs_ordered_sum *sum = NULL;
666 int ret = 0;
667 unsigned long i;
668 unsigned long num_sectors;
669 u32 sectorsize = sdev->dev->dev_root->sectorsize;
670
671 while (!list_empty(&sdev->csum_list)) {
672 sum = list_first_entry(&sdev->csum_list,
673 struct btrfs_ordered_sum, list);
674 if (sum->bytenr > logical)
675 return 0;
676 if (sum->bytenr + sum->len > logical)
677 break;
678
679 ++sdev->stat.csum_discards;
680 list_del(&sum->list);
681 kfree(sum);
682 sum = NULL;
683 }
684 if (!sum)
685 return 0;
686
687 num_sectors = sum->len / sectorsize;
688 for (i = 0; i < num_sectors; ++i) {
689 if (sum->sums[i].bytenr == logical) {
690 memcpy(csum, &sum->sums[i].sum, sdev->csum_size);
691 ret = 1;
692 break;
693 }
694 }
695 if (ret && i == num_sectors - 1) {
696 list_del(&sum->list);
697 kfree(sum);
698 }
699 return ret;
700 }
701
702 /* scrub extent tries to collect up to 64 kB for each bio */
703 static int scrub_extent(struct scrub_dev *sdev, u64 logical, u64 len,
704 u64 physical, u64 flags, u64 gen, u64 mirror_num)
705 {
706 int ret;
707 u8 csum[BTRFS_CSUM_SIZE];
708
709 while (len) {
710 u64 l = min_t(u64, len, PAGE_SIZE);
711 int have_csum = 0;
712
713 if (flags & BTRFS_EXTENT_FLAG_DATA) {
714 /* push csums to sbio */
715 have_csum = scrub_find_csum(sdev, logical, l, csum);
716 if (have_csum == 0)
717 ++sdev->stat.no_csum;
718 }
719 ret = scrub_page(sdev, logical, l, physical, flags, gen,
720 mirror_num, have_csum ? csum : NULL, 0);
721 if (ret)
722 return ret;
723 len -= l;
724 logical += l;
725 physical += l;
726 }
727 return 0;
728 }
729
730 static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev,
731 struct map_lookup *map, int num, u64 base, u64 length)
732 {
733 struct btrfs_path *path;
734 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
735 struct btrfs_root *root = fs_info->extent_root;
736 struct btrfs_root *csum_root = fs_info->csum_root;
737 struct btrfs_extent_item *extent;
738 struct blk_plug plug;
739 u64 flags;
740 int ret;
741 int slot;
742 int i;
743 u64 nstripes;
744 int start_stripe;
745 struct extent_buffer *l;
746 struct btrfs_key key;
747 u64 physical;
748 u64 logical;
749 u64 generation;
750 u64 mirror_num;
751
752 u64 increment = map->stripe_len;
753 u64 offset;
754
755 nstripes = length;
756 offset = 0;
757 do_div(nstripes, map->stripe_len);
758 if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
759 offset = map->stripe_len * num;
760 increment = map->stripe_len * map->num_stripes;
761 mirror_num = 0;
762 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
763 int factor = map->num_stripes / map->sub_stripes;
764 offset = map->stripe_len * (num / map->sub_stripes);
765 increment = map->stripe_len * factor;
766 mirror_num = num % map->sub_stripes;
767 } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
768 increment = map->stripe_len;
769 mirror_num = num % map->num_stripes;
770 } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
771 increment = map->stripe_len;
772 mirror_num = num % map->num_stripes;
773 } else {
774 increment = map->stripe_len;
775 mirror_num = 0;
776 }
777
778 path = btrfs_alloc_path();
779 if (!path)
780 return -ENOMEM;
781
782 path->reada = 2;
783 path->search_commit_root = 1;
784 path->skip_locking = 1;
785
786 /*
787 * find all extents for each stripe and just read them to get
788 * them into the page cache
789 * FIXME: we can do better. build a more intelligent prefetching
790 */
791 logical = base + offset;
792 physical = map->stripes[num].physical;
793 ret = 0;
794 for (i = 0; i < nstripes; ++i) {
795 key.objectid = logical;
796 key.type = BTRFS_EXTENT_ITEM_KEY;
797 key.offset = (u64)0;
798
799 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
800 if (ret < 0)
801 goto out_noplug;
802
803 /*
804 * we might miss half an extent here, but that doesn't matter,
805 * as it's only the prefetch
806 */
807 while (1) {
808 l = path->nodes[0];
809 slot = path->slots[0];
810 if (slot >= btrfs_header_nritems(l)) {
811 ret = btrfs_next_leaf(root, path);
812 if (ret == 0)
813 continue;
814 if (ret < 0)
815 goto out_noplug;
816
817 break;
818 }
819 btrfs_item_key_to_cpu(l, &key, slot);
820
821 if (key.objectid >= logical + map->stripe_len)
822 break;
823
824 path->slots[0]++;
825 }
826 btrfs_release_path(path);
827 logical += increment;
828 physical += map->stripe_len;
829 cond_resched();
830 }
831
832 /*
833 * collect all data csums for the stripe to avoid seeking during
834 * the scrub. This might currently (crc32) end up to be about 1MB
835 */
836 start_stripe = 0;
837 blk_start_plug(&plug);
838 again:
839 logical = base + offset + start_stripe * increment;
840 for (i = start_stripe; i < nstripes; ++i) {
841 ret = btrfs_lookup_csums_range(csum_root, logical,
842 logical + map->stripe_len - 1,
843 &sdev->csum_list, 1);
844 if (ret)
845 goto out;
846
847 logical += increment;
848 cond_resched();
849 }
850 /*
851 * now find all extents for each stripe and scrub them
852 */
853 logical = base + offset + start_stripe * increment;
854 physical = map->stripes[num].physical + start_stripe * map->stripe_len;
855 ret = 0;
856 for (i = start_stripe; i < nstripes; ++i) {
857 /*
858 * canceled?
859 */
860 if (atomic_read(&fs_info->scrub_cancel_req) ||
861 atomic_read(&sdev->cancel_req)) {
862 ret = -ECANCELED;
863 goto out;
864 }
865 /*
866 * check to see if we have to pause
867 */
868 if (atomic_read(&fs_info->scrub_pause_req)) {
869 /* push queued extents */
870 scrub_submit(sdev);
871 wait_event(sdev->list_wait,
872 atomic_read(&sdev->in_flight) == 0);
873 atomic_inc(&fs_info->scrubs_paused);
874 wake_up(&fs_info->scrub_pause_wait);
875 mutex_lock(&fs_info->scrub_lock);
876 while (atomic_read(&fs_info->scrub_pause_req)) {
877 mutex_unlock(&fs_info->scrub_lock);
878 wait_event(fs_info->scrub_pause_wait,
879 atomic_read(&fs_info->scrub_pause_req) == 0);
880 mutex_lock(&fs_info->scrub_lock);
881 }
882 atomic_dec(&fs_info->scrubs_paused);
883 mutex_unlock(&fs_info->scrub_lock);
884 wake_up(&fs_info->scrub_pause_wait);
885 scrub_free_csums(sdev);
886 start_stripe = i;
887 goto again;
888 }
889
890 key.objectid = logical;
891 key.type = BTRFS_EXTENT_ITEM_KEY;
892 key.offset = (u64)0;
893
894 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
895 if (ret < 0)
896 goto out;
897 if (ret > 0) {
898 ret = btrfs_previous_item(root, path, 0,
899 BTRFS_EXTENT_ITEM_KEY);
900 if (ret < 0)
901 goto out;
902 if (ret > 0) {
903 /* there's no smaller item, so stick with the
904 * larger one */
905 btrfs_release_path(path);
906 ret = btrfs_search_slot(NULL, root, &key,
907 path, 0, 0);
908 if (ret < 0)
909 goto out;
910 }
911 }
912
913 while (1) {
914 l = path->nodes[0];
915 slot = path->slots[0];
916 if (slot >= btrfs_header_nritems(l)) {
917 ret = btrfs_next_leaf(root, path);
918 if (ret == 0)
919 continue;
920 if (ret < 0)
921 goto out;
922
923 break;
924 }
925 btrfs_item_key_to_cpu(l, &key, slot);
926
927 if (key.objectid + key.offset <= logical)
928 goto next;
929
930 if (key.objectid >= logical + map->stripe_len)
931 break;
932
933 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY)
934 goto next;
935
936 extent = btrfs_item_ptr(l, slot,
937 struct btrfs_extent_item);
938 flags = btrfs_extent_flags(l, extent);
939 generation = btrfs_extent_generation(l, extent);
940
941 if (key.objectid < logical &&
942 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) {
943 printk(KERN_ERR
944 "btrfs scrub: tree block %llu spanning "
945 "stripes, ignored. logical=%llu\n",
946 (unsigned long long)key.objectid,
947 (unsigned long long)logical);
948 goto next;
949 }
950
951 /*
952 * trim extent to this stripe
953 */
954 if (key.objectid < logical) {
955 key.offset -= logical - key.objectid;
956 key.objectid = logical;
957 }
958 if (key.objectid + key.offset >
959 logical + map->stripe_len) {
960 key.offset = logical + map->stripe_len -
961 key.objectid;
962 }
963
964 ret = scrub_extent(sdev, key.objectid, key.offset,
965 key.objectid - logical + physical,
966 flags, generation, mirror_num);
967 if (ret)
968 goto out;
969
970 next:
971 path->slots[0]++;
972 }
973 btrfs_release_path(path);
974 logical += increment;
975 physical += map->stripe_len;
976 spin_lock(&sdev->stat_lock);
977 sdev->stat.last_physical = physical;
978 spin_unlock(&sdev->stat_lock);
979 }
980 /* push queued extents */
981 scrub_submit(sdev);
982
983 out:
984 blk_finish_plug(&plug);
985 out_noplug:
986 btrfs_free_path(path);
987 return ret < 0 ? ret : 0;
988 }
989
990 static noinline_for_stack int scrub_chunk(struct scrub_dev *sdev,
991 u64 chunk_tree, u64 chunk_objectid, u64 chunk_offset, u64 length)
992 {
993 struct btrfs_mapping_tree *map_tree =
994 &sdev->dev->dev_root->fs_info->mapping_tree;
995 struct map_lookup *map;
996 struct extent_map *em;
997 int i;
998 int ret = -EINVAL;
999
1000 read_lock(&map_tree->map_tree.lock);
1001 em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
1002 read_unlock(&map_tree->map_tree.lock);
1003
1004 if (!em)
1005 return -EINVAL;
1006
1007 map = (struct map_lookup *)em->bdev;
1008 if (em->start != chunk_offset)
1009 goto out;
1010
1011 if (em->len < length)
1012 goto out;
1013
1014 for (i = 0; i < map->num_stripes; ++i) {
1015 if (map->stripes[i].dev == sdev->dev) {
1016 ret = scrub_stripe(sdev, map, i, chunk_offset, length);
1017 if (ret)
1018 goto out;
1019 }
1020 }
1021 out:
1022 free_extent_map(em);
1023
1024 return ret;
1025 }
1026
1027 static noinline_for_stack
1028 int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end)
1029 {
1030 struct btrfs_dev_extent *dev_extent = NULL;
1031 struct btrfs_path *path;
1032 struct btrfs_root *root = sdev->dev->dev_root;
1033 struct btrfs_fs_info *fs_info = root->fs_info;
1034 u64 length;
1035 u64 chunk_tree;
1036 u64 chunk_objectid;
1037 u64 chunk_offset;
1038 int ret;
1039 int slot;
1040 struct extent_buffer *l;
1041 struct btrfs_key key;
1042 struct btrfs_key found_key;
1043 struct btrfs_block_group_cache *cache;
1044
1045 path = btrfs_alloc_path();
1046 if (!path)
1047 return -ENOMEM;
1048
1049 path->reada = 2;
1050 path->search_commit_root = 1;
1051 path->skip_locking = 1;
1052
1053 key.objectid = sdev->dev->devid;
1054 key.offset = 0ull;
1055 key.type = BTRFS_DEV_EXTENT_KEY;
1056
1057
1058 while (1) {
1059 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1060 if (ret < 0)
1061 break;
1062 if (ret > 0) {
1063 if (path->slots[0] >=
1064 btrfs_header_nritems(path->nodes[0])) {
1065 ret = btrfs_next_leaf(root, path);
1066 if (ret)
1067 break;
1068 }
1069 }
1070
1071 l = path->nodes[0];
1072 slot = path->slots[0];
1073
1074 btrfs_item_key_to_cpu(l, &found_key, slot);
1075
1076 if (found_key.objectid != sdev->dev->devid)
1077 break;
1078
1079 if (btrfs_key_type(&found_key) != BTRFS_DEV_EXTENT_KEY)
1080 break;
1081
1082 if (found_key.offset >= end)
1083 break;
1084
1085 if (found_key.offset < key.offset)
1086 break;
1087
1088 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1089 length = btrfs_dev_extent_length(l, dev_extent);
1090
1091 if (found_key.offset + length <= start) {
1092 key.offset = found_key.offset + length;
1093 btrfs_release_path(path);
1094 continue;
1095 }
1096
1097 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
1098 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
1099 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
1100
1101 /*
1102 * get a reference on the corresponding block group to prevent
1103 * the chunk from going away while we scrub it
1104 */
1105 cache = btrfs_lookup_block_group(fs_info, chunk_offset);
1106 if (!cache) {
1107 ret = -ENOENT;
1108 break;
1109 }
1110 ret = scrub_chunk(sdev, chunk_tree, chunk_objectid,
1111 chunk_offset, length);
1112 btrfs_put_block_group(cache);
1113 if (ret)
1114 break;
1115
1116 key.offset = found_key.offset + length;
1117 btrfs_release_path(path);
1118 }
1119
1120 btrfs_free_path(path);
1121
1122 /*
1123 * ret can still be 1 from search_slot or next_leaf,
1124 * that's not an error
1125 */
1126 return ret < 0 ? ret : 0;
1127 }
1128
1129 static noinline_for_stack int scrub_supers(struct scrub_dev *sdev)
1130 {
1131 int i;
1132 u64 bytenr;
1133 u64 gen;
1134 int ret;
1135 struct btrfs_device *device = sdev->dev;
1136 struct btrfs_root *root = device->dev_root;
1137
1138 gen = root->fs_info->last_trans_committed;
1139
1140 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
1141 bytenr = btrfs_sb_offset(i);
1142 if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
1143 break;
1144
1145 ret = scrub_page(sdev, bytenr, PAGE_SIZE, bytenr,
1146 BTRFS_EXTENT_FLAG_SUPER, gen, i, NULL, 1);
1147 if (ret)
1148 return ret;
1149 }
1150 wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
1151
1152 return 0;
1153 }
1154
1155 /*
1156 * get a reference count on fs_info->scrub_workers. start worker if necessary
1157 */
1158 static noinline_for_stack int scrub_workers_get(struct btrfs_root *root)
1159 {
1160 struct btrfs_fs_info *fs_info = root->fs_info;
1161
1162 mutex_lock(&fs_info->scrub_lock);
1163 if (fs_info->scrub_workers_refcnt == 0) {
1164 btrfs_init_workers(&fs_info->scrub_workers, "scrub",
1165 fs_info->thread_pool_size, &fs_info->generic_worker);
1166 fs_info->scrub_workers.idle_thresh = 4;
1167 btrfs_start_workers(&fs_info->scrub_workers, 1);
1168 }
1169 ++fs_info->scrub_workers_refcnt;
1170 mutex_unlock(&fs_info->scrub_lock);
1171
1172 return 0;
1173 }
1174
1175 static noinline_for_stack void scrub_workers_put(struct btrfs_root *root)
1176 {
1177 struct btrfs_fs_info *fs_info = root->fs_info;
1178
1179 mutex_lock(&fs_info->scrub_lock);
1180 if (--fs_info->scrub_workers_refcnt == 0)
1181 btrfs_stop_workers(&fs_info->scrub_workers);
1182 WARN_ON(fs_info->scrub_workers_refcnt < 0);
1183 mutex_unlock(&fs_info->scrub_lock);
1184 }
1185
1186
1187 int btrfs_scrub_dev(struct btrfs_root *root, u64 devid, u64 start, u64 end,
1188 struct btrfs_scrub_progress *progress, int readonly)
1189 {
1190 struct scrub_dev *sdev;
1191 struct btrfs_fs_info *fs_info = root->fs_info;
1192 int ret;
1193 struct btrfs_device *dev;
1194
1195 if (btrfs_fs_closing(root->fs_info))
1196 return -EINVAL;
1197
1198 /*
1199 * check some assumptions
1200 */
1201 if (root->sectorsize != PAGE_SIZE ||
1202 root->sectorsize != root->leafsize ||
1203 root->sectorsize != root->nodesize) {
1204 printk(KERN_ERR "btrfs_scrub: size assumptions fail\n");
1205 return -EINVAL;
1206 }
1207
1208 ret = scrub_workers_get(root);
1209 if (ret)
1210 return ret;
1211
1212 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1213 dev = btrfs_find_device(root, devid, NULL, NULL);
1214 if (!dev || dev->missing) {
1215 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1216 scrub_workers_put(root);
1217 return -ENODEV;
1218 }
1219 mutex_lock(&fs_info->scrub_lock);
1220
1221 if (!dev->in_fs_metadata) {
1222 mutex_unlock(&fs_info->scrub_lock);
1223 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1224 scrub_workers_put(root);
1225 return -ENODEV;
1226 }
1227
1228 if (dev->scrub_device) {
1229 mutex_unlock(&fs_info->scrub_lock);
1230 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1231 scrub_workers_put(root);
1232 return -EINPROGRESS;
1233 }
1234 sdev = scrub_setup_dev(dev);
1235 if (IS_ERR(sdev)) {
1236 mutex_unlock(&fs_info->scrub_lock);
1237 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1238 scrub_workers_put(root);
1239 return PTR_ERR(sdev);
1240 }
1241 sdev->readonly = readonly;
1242 dev->scrub_device = sdev;
1243
1244 atomic_inc(&fs_info->scrubs_running);
1245 mutex_unlock(&fs_info->scrub_lock);
1246 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1247
1248 down_read(&fs_info->scrub_super_lock);
1249 ret = scrub_supers(sdev);
1250 up_read(&fs_info->scrub_super_lock);
1251
1252 if (!ret)
1253 ret = scrub_enumerate_chunks(sdev, start, end);
1254
1255 wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
1256
1257 atomic_dec(&fs_info->scrubs_running);
1258 wake_up(&fs_info->scrub_pause_wait);
1259
1260 if (progress)
1261 memcpy(progress, &sdev->stat, sizeof(*progress));
1262
1263 mutex_lock(&fs_info->scrub_lock);
1264 dev->scrub_device = NULL;
1265 mutex_unlock(&fs_info->scrub_lock);
1266
1267 scrub_free_dev(sdev);
1268 scrub_workers_put(root);
1269
1270 return ret;
1271 }
1272
1273 int btrfs_scrub_pause(struct btrfs_root *root)
1274 {
1275 struct btrfs_fs_info *fs_info = root->fs_info;
1276
1277 mutex_lock(&fs_info->scrub_lock);
1278 atomic_inc(&fs_info->scrub_pause_req);
1279 while (atomic_read(&fs_info->scrubs_paused) !=
1280 atomic_read(&fs_info->scrubs_running)) {
1281 mutex_unlock(&fs_info->scrub_lock);
1282 wait_event(fs_info->scrub_pause_wait,
1283 atomic_read(&fs_info->scrubs_paused) ==
1284 atomic_read(&fs_info->scrubs_running));
1285 mutex_lock(&fs_info->scrub_lock);
1286 }
1287 mutex_unlock(&fs_info->scrub_lock);
1288
1289 return 0;
1290 }
1291
1292 int btrfs_scrub_continue(struct btrfs_root *root)
1293 {
1294 struct btrfs_fs_info *fs_info = root->fs_info;
1295
1296 atomic_dec(&fs_info->scrub_pause_req);
1297 wake_up(&fs_info->scrub_pause_wait);
1298 return 0;
1299 }
1300
1301 int btrfs_scrub_pause_super(struct btrfs_root *root)
1302 {
1303 down_write(&root->fs_info->scrub_super_lock);
1304 return 0;
1305 }
1306
1307 int btrfs_scrub_continue_super(struct btrfs_root *root)
1308 {
1309 up_write(&root->fs_info->scrub_super_lock);
1310 return 0;
1311 }
1312
1313 int btrfs_scrub_cancel(struct btrfs_root *root)
1314 {
1315 struct btrfs_fs_info *fs_info = root->fs_info;
1316
1317 mutex_lock(&fs_info->scrub_lock);
1318 if (!atomic_read(&fs_info->scrubs_running)) {
1319 mutex_unlock(&fs_info->scrub_lock);
1320 return -ENOTCONN;
1321 }
1322
1323 atomic_inc(&fs_info->scrub_cancel_req);
1324 while (atomic_read(&fs_info->scrubs_running)) {
1325 mutex_unlock(&fs_info->scrub_lock);
1326 wait_event(fs_info->scrub_pause_wait,
1327 atomic_read(&fs_info->scrubs_running) == 0);
1328 mutex_lock(&fs_info->scrub_lock);
1329 }
1330 atomic_dec(&fs_info->scrub_cancel_req);
1331 mutex_unlock(&fs_info->scrub_lock);
1332
1333 return 0;
1334 }
1335
1336 int btrfs_scrub_cancel_dev(struct btrfs_root *root, struct btrfs_device *dev)
1337 {
1338 struct btrfs_fs_info *fs_info = root->fs_info;
1339 struct scrub_dev *sdev;
1340
1341 mutex_lock(&fs_info->scrub_lock);
1342 sdev = dev->scrub_device;
1343 if (!sdev) {
1344 mutex_unlock(&fs_info->scrub_lock);
1345 return -ENOTCONN;
1346 }
1347 atomic_inc(&sdev->cancel_req);
1348 while (dev->scrub_device) {
1349 mutex_unlock(&fs_info->scrub_lock);
1350 wait_event(fs_info->scrub_pause_wait,
1351 dev->scrub_device == NULL);
1352 mutex_lock(&fs_info->scrub_lock);
1353 }
1354 mutex_unlock(&fs_info->scrub_lock);
1355
1356 return 0;
1357 }
1358 int btrfs_scrub_cancel_devid(struct btrfs_root *root, u64 devid)
1359 {
1360 struct btrfs_fs_info *fs_info = root->fs_info;
1361 struct btrfs_device *dev;
1362 int ret;
1363
1364 /*
1365 * we have to hold the device_list_mutex here so the device
1366 * does not go away in cancel_dev. FIXME: find a better solution
1367 */
1368 mutex_lock(&fs_info->fs_devices->device_list_mutex);
1369 dev = btrfs_find_device(root, devid, NULL, NULL);
1370 if (!dev) {
1371 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1372 return -ENODEV;
1373 }
1374 ret = btrfs_scrub_cancel_dev(root, dev);
1375 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1376
1377 return ret;
1378 }
1379
1380 int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
1381 struct btrfs_scrub_progress *progress)
1382 {
1383 struct btrfs_device *dev;
1384 struct scrub_dev *sdev = NULL;
1385
1386 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1387 dev = btrfs_find_device(root, devid, NULL, NULL);
1388 if (dev)
1389 sdev = dev->scrub_device;
1390 if (sdev)
1391 memcpy(progress, &sdev->stat, sizeof(*progress));
1392 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1393
1394 return dev ? (sdev ? 0 : -ENOTCONN) : -ENODEV;
1395 }
linux-next