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btrfs scrub: make fixups sync
[mirror_ubuntu-hirsute-kernel.git] / fs / btrfs / scrub.c
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a2de733c
AJ		 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/sched.h>
20#include <linux/pagemap.h>
21#include <linux/writeback.h>
22#include <linux/blkdev.h>
23#include <linux/rbtree.h>
24#include <linux/slab.h>
25#include <linux/workqueue.h>
26#include "ctree.h"
27#include "volumes.h"
28#include "disk-io.h"
29#include "ordered-data.h"
30
31/*
32 * This is only the first step towards a full-features scrub. It reads all
33 * extent and super block and verifies the checksums. In case a bad checksum
34 * is found or the extent cannot be read, good data will be written back if
35 * any can be found.
36 *
37 * Future enhancements:
38 * - To enhance the performance, better read-ahead strategies for the
39 * extent-tree can be employed.
40 * - In case an unrepairable extent is encountered, track which files are
41 * affected and report them
42 * - In case of a read error on files with nodatasum, map the file and read
43 * the extent to trigger a writeback of the good copy
44 * - track and record media errors, throw out bad devices
45 * - add a readonly mode
46 * - add a mode to also read unallocated space
47 * - make the prefetch cancellable
48 */
49
50struct scrub_bio;
51struct scrub_page;
52struct scrub_dev;
a2de733c
AJ		 53static void scrub_bio_end_io(struct bio *bio, int err);
54static void scrub_checksum(struct btrfs_work *work);
55static int scrub_checksum_data(struct scrub_dev *sdev,
56 struct scrub_page *spag, void *buffer);
57static int scrub_checksum_tree_block(struct scrub_dev *sdev,
58 struct scrub_page *spag, u64 logical,
59 void *buffer);
60static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer);
96e36920
ID		 61static int scrub_fixup_check(struct scrub_bio *sbio, int ix);
62static void scrub_fixup_end_io(struct bio *bio, int err);
63static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector,
64 struct page *page);
65static void scrub_fixup(struct scrub_bio *sbio, int ix);
a2de733c
AJ		 66
67#define SCRUB_PAGES_PER_BIO 16 /* 64k per bio */
68#define SCRUB_BIOS_PER_DEV 16 /* 1 MB per device in flight */
69
70struct scrub_page {
71 u64 flags; /* extent flags */
72 u64 generation;
73 u64 mirror_num;
74 int have_csum;
75 u8 csum[BTRFS_CSUM_SIZE];
76};
77
78struct scrub_bio {
79 int index;
80 struct scrub_dev *sdev;
81 struct bio *bio;
82 int err;
83 u64 logical;
84 u64 physical;
85 struct scrub_page spag[SCRUB_PAGES_PER_BIO];
86 u64 count;
87 int next_free;
88 struct btrfs_work work;
89};
90
91struct scrub_dev {
92 struct scrub_bio *bios[SCRUB_BIOS_PER_DEV];
93 struct btrfs_device *dev;
94 int first_free;
95 int curr;
96 atomic_t in_flight;
97 spinlock_t list_lock;
98 wait_queue_head_t list_wait;
99 u16 csum_size;
100 struct list_head csum_list;
101 atomic_t cancel_req;
102 /*
103 * statistics
104 */
105 struct btrfs_scrub_progress stat;
106 spinlock_t stat_lock;
107};
108
a2de733c
AJ		 109static void scrub_free_csums(struct scrub_dev *sdev)
110{
111 while (!list_empty(&sdev->csum_list)) {
112 struct btrfs_ordered_sum *sum;
113 sum = list_first_entry(&sdev->csum_list,
114 struct btrfs_ordered_sum, list);
115 list_del(&sum->list);
116 kfree(sum);
117 }
118}
119
120static noinline_for_stack void scrub_free_dev(struct scrub_dev *sdev)
121{
122 int i;
123 int j;
124 struct page *last_page;
125
126 if (!sdev)
127 return;
128
129 for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
130 struct scrub_bio *sbio = sdev->bios[i];
131 struct bio *bio;
132
133 if (!sbio)
134 break;
135
136 bio = sbio->bio;
137 if (bio) {
138 last_page = NULL;
139 for (j = 0; j < bio->bi_vcnt; ++j) {
140 if (bio->bi_io_vec[j].bv_page == last_page)
141 continue;
142 last_page = bio->bi_io_vec[j].bv_page;
143 __free_page(last_page);
144 }
145 bio_put(bio);
146 }
147 kfree(sbio);
148 }
149
150 scrub_free_csums(sdev);
151 kfree(sdev);
152}
153
154static noinline_for_stack
155struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev)
156{
157 struct scrub_dev *sdev;
158 int i;
159 int j;
160 int ret;
161 struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
162
163 sdev = kzalloc(sizeof(*sdev), GFP_NOFS);
164 if (!sdev)
165 goto nomem;
166 sdev->dev = dev;
167 for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
168 struct bio *bio;
169 struct scrub_bio *sbio;
170
171 sbio = kzalloc(sizeof(*sbio), GFP_NOFS);
172 if (!sbio)
173 goto nomem;
174 sdev->bios[i] = sbio;
175
176 bio = bio_kmalloc(GFP_NOFS, SCRUB_PAGES_PER_BIO);
177 if (!bio)
178 goto nomem;
179
180 sbio->index = i;
181 sbio->sdev = sdev;
182 sbio->bio = bio;
183 sbio->count = 0;
184 sbio->work.func = scrub_checksum;
185 bio->bi_private = sdev->bios[i];
186 bio->bi_end_io = scrub_bio_end_io;
187 bio->bi_sector = 0;
188 bio->bi_bdev = dev->bdev;
189 bio->bi_size = 0;
190
191 for (j = 0; j < SCRUB_PAGES_PER_BIO; ++j) {
192 struct page *page;
193 page = alloc_page(GFP_NOFS);
194 if (!page)
195 goto nomem;
196
197 ret = bio_add_page(bio, page, PAGE_SIZE, 0);
198 if (!ret)
199 goto nomem;
200 }
201 WARN_ON(bio->bi_vcnt != SCRUB_PAGES_PER_BIO);
202
203 if (i != SCRUB_BIOS_PER_DEV-1)
204 sdev->bios[i]->next_free = i + 1;
205 else
206 sdev->bios[i]->next_free = -1;
207 }
208 sdev->first_free = 0;
209 sdev->curr = -1;
210 atomic_set(&sdev->in_flight, 0);
211 atomic_set(&sdev->cancel_req, 0);
212 sdev->csum_size = btrfs_super_csum_size(&fs_info->super_copy);
213 INIT_LIST_HEAD(&sdev->csum_list);
214
215 spin_lock_init(&sdev->list_lock);
216 spin_lock_init(&sdev->stat_lock);
217 init_waitqueue_head(&sdev->list_wait);
218 return sdev;
219
220nomem:
221 scrub_free_dev(sdev);
222 return ERR_PTR(-ENOMEM);
223}
224
225/*
226 * scrub_recheck_error gets called when either verification of the page
227 * failed or the bio failed to read, e.g. with EIO. In the latter case,
228 * recheck_error gets called for every page in the bio, even though only
229 * one may be bad
230 */
231static void scrub_recheck_error(struct scrub_bio *sbio, int ix)
232{
96e36920
ID		 233 if (sbio->err) {
234 if (scrub_fixup_io(READ, sbio->sdev->dev->bdev,
235 (sbio->physical + ix * PAGE_SIZE) >> 9,
236 sbio->bio->bi_io_vec[ix].bv_page) == 0) {
237 if (scrub_fixup_check(sbio, ix) == 0)
238 return;
239 }
a2de733c
AJ		 240 }
241
96e36920 242 scrub_fixup(sbio, ix);
a2de733c
AJ		 243}
244
96e36920 245static int scrub_fixup_check(struct scrub_bio *sbio, int ix)
a2de733c
AJ		 246{
247 int ret = 1;
248 struct page *page;
249 void *buffer;
96e36920 250 u64 flags = sbio->spag[ix].flags;
a2de733c 251
96e36920 252 page = sbio->bio->bi_io_vec[ix].bv_page;
a2de733c
AJ		 253 buffer = kmap_atomic(page, KM_USER0);
254 if (flags & BTRFS_EXTENT_FLAG_DATA) {
96e36920
ID		 255 ret = scrub_checksum_data(sbio->sdev,
256 sbio->spag + ix, buffer);
a2de733c 257 } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
96e36920
ID		 258 ret = scrub_checksum_tree_block(sbio->sdev,
259 sbio->spag + ix,
260 sbio->logical + ix * PAGE_SIZE,
a2de733c
AJ		 261 buffer);
262 } else {
263 WARN_ON(1);
264 }
265 kunmap_atomic(buffer, KM_USER0);
266
267 return ret;
268}
269
a2de733c
AJ		 270static void scrub_fixup_end_io(struct bio *bio, int err)
271{
272 complete((struct completion *)bio->bi_private);
273}
274
96e36920 275static void scrub_fixup(struct scrub_bio *sbio, int ix)
a2de733c 276{
96e36920 277 struct scrub_dev *sdev = sbio->sdev;
a2de733c
AJ		 278 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
279 struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
280 struct btrfs_multi_bio *multi = NULL;
96e36920 281 u64 logical = sbio->logical + ix * PAGE_SIZE;
a2de733c
AJ		 282 u64 length;
283 int i;
284 int ret;
285 DECLARE_COMPLETION_ONSTACK(complete);
286
96e36920
ID		 287 if ((sbio->spag[ix].flags & BTRFS_EXTENT_FLAG_DATA) &&
288 (sbio->spag[ix].have_csum == 0)) {
a2de733c
AJ		 289 /*
290 * nodatasum, don't try to fix anything
291 * FIXME: we can do better, open the inode and trigger a
292 * writeback
293 */
294 goto uncorrectable;
295 }
296
297 length = PAGE_SIZE;
96e36920 298 ret = btrfs_map_block(map_tree, REQ_WRITE, logical, &length,
a2de733c
AJ		 299 &multi, 0);
300 if (ret || !multi || length < PAGE_SIZE) {
301 printk(KERN_ERR
302 "scrub_fixup: btrfs_map_block failed us for %llu\n",
96e36920 303 (unsigned long long)logical);
a2de733c
AJ		 304 WARN_ON(1);
305 return;
306 }
307
96e36920 308 if (multi->num_stripes == 1)
a2de733c
AJ		 309 /* there aren't any replicas */
310 goto uncorrectable;
a2de733c
AJ		 311
312 /*
313 * first find a good copy
314 */
315 for (i = 0; i < multi->num_stripes; ++i) {
96e36920 316 if (i == sbio->spag[ix].mirror_num)
a2de733c
AJ		 317 continue;
318
96e36920
ID		 319 if (scrub_fixup_io(READ, multi->stripes[i].dev->bdev,
320 multi->stripes[i].physical >> 9,
321 sbio->bio->bi_io_vec[ix].bv_page)) {
a2de733c
AJ		 322 /* I/O-error, this is not a good copy */
323 continue;
96e36920 324 }
a2de733c 325
96e36920 326 if (scrub_fixup_check(sbio, ix) == 0)
a2de733c
AJ		 327 break;
328 }
329 if (i == multi->num_stripes)
330 goto uncorrectable;
331
332 /*
96e36920 333 * bi_io_vec[ix].bv_page now contains good data, write it back
a2de733c 334 */
96e36920
ID		 335 if (scrub_fixup_io(WRITE, sdev->dev->bdev,
336 (sbio->physical + ix * PAGE_SIZE) >> 9,
337 sbio->bio->bi_io_vec[ix].bv_page)) {
a2de733c
AJ		 338 /* I/O-error, writeback failed, give up */
339 goto uncorrectable;
96e36920 340 }
a2de733c
AJ		 341
342 kfree(multi);
343 spin_lock(&sdev->stat_lock);
344 ++sdev->stat.corrected_errors;
345 spin_unlock(&sdev->stat_lock);
346
347 if (printk_ratelimit())
348 printk(KERN_ERR "btrfs: fixed up at %llu\n",
96e36920 349 (unsigned long long)logical);
a2de733c
AJ		 350 return;
351
352uncorrectable:
353 kfree(multi);
354 spin_lock(&sdev->stat_lock);
355 ++sdev->stat.uncorrectable_errors;
356 spin_unlock(&sdev->stat_lock);
357
358 if (printk_ratelimit())
359 printk(KERN_ERR "btrfs: unable to fixup at %llu\n",
96e36920
ID		 360 (unsigned long long)logical);
361}
362
363static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector,
364 struct page *page)
365{
366 struct bio *bio = NULL;
367 int ret;
368 DECLARE_COMPLETION_ONSTACK(complete);
369
370 /* we are going to wait on this IO */
371 rw |= REQ_SYNC | REQ_UNPLUG;
372
373 bio = bio_alloc(GFP_NOFS, 1);
374 bio->bi_bdev = bdev;
375 bio->bi_sector = sector;
376 bio_add_page(bio, page, PAGE_SIZE, 0);
377 bio->bi_end_io = scrub_fixup_end_io;
378 bio->bi_private = &complete;
379 submit_bio(rw, bio);
380
381 wait_for_completion(&complete);
382
383 ret = !test_bit(BIO_UPTODATE, &bio->bi_flags);
384 bio_put(bio);
385 return ret;
a2de733c
AJ		 386}
387
388static void scrub_bio_end_io(struct bio *bio, int err)
389{
390 struct scrub_bio *sbio = bio->bi_private;
391 struct scrub_dev *sdev = sbio->sdev;
392 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
393
394 sbio->err = err;
395
396 btrfs_queue_worker(&fs_info->scrub_workers, &sbio->work);
397}
398
399static void scrub_checksum(struct btrfs_work *work)
400{
401 struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
402 struct scrub_dev *sdev = sbio->sdev;
403 struct page *page;
404 void *buffer;
405 int i;
406 u64 flags;
407 u64 logical;
408 int ret;
409
410 if (sbio->err) {
a2de733c
AJ		 411 for (i = 0; i < sbio->count; ++i)
412 scrub_recheck_error(sbio, i);
96e36920
ID		 413
414 sbio->bio->bi_flags &= ~(BIO_POOL_MASK - 1);
415 sbio->bio->bi_flags |= 1 << BIO_UPTODATE;
416 sbio->bio->bi_phys_segments = 0;
417 sbio->bio->bi_idx = 0;
418
419 for (i = 0; i < sbio->count; i++) {
420 struct bio_vec *bi;
421 bi = &sbio->bio->bi_io_vec[i];
422 bi->bv_offset = 0;
423 bi->bv_len = PAGE_SIZE;
424 }
425
a2de733c
AJ		 426 spin_lock(&sdev->stat_lock);
427 ++sdev->stat.read_errors;
428 spin_unlock(&sdev->stat_lock);
a2de733c
AJ		 429 goto out;
430 }
431 for (i = 0; i < sbio->count; ++i) {
432 page = sbio->bio->bi_io_vec[i].bv_page;
433 buffer = kmap_atomic(page, KM_USER0);
434 flags = sbio->spag[i].flags;
435 logical = sbio->logical + i * PAGE_SIZE;
436 ret = 0;
437 if (flags & BTRFS_EXTENT_FLAG_DATA) {
438 ret = scrub_checksum_data(sdev, sbio->spag + i, buffer);
439 } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
440 ret = scrub_checksum_tree_block(sdev, sbio->spag + i,
441 logical, buffer);
442 } else if (flags & BTRFS_EXTENT_FLAG_SUPER) {
443 BUG_ON(i);
444 (void)scrub_checksum_super(sbio, buffer);
445 } else {
446 WARN_ON(1);
447 }
448 kunmap_atomic(buffer, KM_USER0);
449 if (ret)
450 scrub_recheck_error(sbio, i);
451 }
452
453out:
454 spin_lock(&sdev->list_lock);
455 sbio->next_free = sdev->first_free;
456 sdev->first_free = sbio->index;
457 spin_unlock(&sdev->list_lock);
a2de733c
AJ		 458 atomic_dec(&sdev->in_flight);
459 wake_up(&sdev->list_wait);
460}
461
462static int scrub_checksum_data(struct scrub_dev *sdev,
463 struct scrub_page *spag, void *buffer)
464{
465 u8 csum[BTRFS_CSUM_SIZE];
466 u32 crc = ~(u32)0;
467 int fail = 0;
468 struct btrfs_root *root = sdev->dev->dev_root;
469
470 if (!spag->have_csum)
471 return 0;
472
473 crc = btrfs_csum_data(root, buffer, crc, PAGE_SIZE);
474 btrfs_csum_final(crc, csum);
475 if (memcmp(csum, spag->csum, sdev->csum_size))
476 fail = 1;
477
478 spin_lock(&sdev->stat_lock);
479 ++sdev->stat.data_extents_scrubbed;
480 sdev->stat.data_bytes_scrubbed += PAGE_SIZE;
481 if (fail)
482 ++sdev->stat.csum_errors;
483 spin_unlock(&sdev->stat_lock);
484
485 return fail;
486}
487
488static int scrub_checksum_tree_block(struct scrub_dev *sdev,
489 struct scrub_page *spag, u64 logical,
490 void *buffer)
491{
492 struct btrfs_header *h;
493 struct btrfs_root *root = sdev->dev->dev_root;
494 struct btrfs_fs_info *fs_info = root->fs_info;
495 u8 csum[BTRFS_CSUM_SIZE];
496 u32 crc = ~(u32)0;
497 int fail = 0;
498 int crc_fail = 0;
499
500 /*
501 * we don't use the getter functions here, as we
502 * a) don't have an extent buffer and
503 * b) the page is already kmapped
504 */
505 h = (struct btrfs_header *)buffer;
506
507 if (logical != le64_to_cpu(h->bytenr))
508 ++fail;
509
510 if (spag->generation != le64_to_cpu(h->generation))
511 ++fail;
512
513 if (memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
514 ++fail;
515
516 if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
517 BTRFS_UUID_SIZE))
518 ++fail;
519
520 crc = btrfs_csum_data(root, buffer + BTRFS_CSUM_SIZE, crc,
521 PAGE_SIZE - BTRFS_CSUM_SIZE);
522 btrfs_csum_final(crc, csum);
523 if (memcmp(csum, h->csum, sdev->csum_size))
524 ++crc_fail;
525
526 spin_lock(&sdev->stat_lock);
527 ++sdev->stat.tree_extents_scrubbed;
528 sdev->stat.tree_bytes_scrubbed += PAGE_SIZE;
529 if (crc_fail)
530 ++sdev->stat.csum_errors;
531 if (fail)
532 ++sdev->stat.verify_errors;
533 spin_unlock(&sdev->stat_lock);
534
535 return fail || crc_fail;
536}
537
538static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer)
539{
540 struct btrfs_super_block *s;
541 u64 logical;
542 struct scrub_dev *sdev = sbio->sdev;
543 struct btrfs_root *root = sdev->dev->dev_root;
544 struct btrfs_fs_info *fs_info = root->fs_info;
545 u8 csum[BTRFS_CSUM_SIZE];
546 u32 crc = ~(u32)0;
547 int fail = 0;
548
549 s = (struct btrfs_super_block *)buffer;
550 logical = sbio->logical;
551
552 if (logical != le64_to_cpu(s->bytenr))
553 ++fail;
554
555 if (sbio->spag[0].generation != le64_to_cpu(s->generation))
556 ++fail;
557
558 if (memcmp(s->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
559 ++fail;
560
561 crc = btrfs_csum_data(root, buffer + BTRFS_CSUM_SIZE, crc,
562 PAGE_SIZE - BTRFS_CSUM_SIZE);
563 btrfs_csum_final(crc, csum);
564 if (memcmp(csum, s->csum, sbio->sdev->csum_size))
565 ++fail;
566
567 if (fail) {
568 /*
569 * if we find an error in a super block, we just report it.
570 * They will get written with the next transaction commit
571 * anyway
572 */
573 spin_lock(&sdev->stat_lock);
574 ++sdev->stat.super_errors;
575 spin_unlock(&sdev->stat_lock);
576 }
577
578 return fail;
579}
580
581static int scrub_submit(struct scrub_dev *sdev)
582{
583 struct scrub_bio *sbio;
584
585 if (sdev->curr == -1)
586 return 0;
587
588 sbio = sdev->bios[sdev->curr];
589
590 sbio->bio->bi_sector = sbio->physical >> 9;
591 sbio->bio->bi_size = sbio->count * PAGE_SIZE;
592 sbio->bio->bi_next = NULL;
593 sbio->bio->bi_flags |= 1 << BIO_UPTODATE;
594 sbio->bio->bi_comp_cpu = -1;
595 sbio->bio->bi_bdev = sdev->dev->bdev;
596 sbio->err = 0;
597 sdev->curr = -1;
598 atomic_inc(&sdev->in_flight);
599
600 submit_bio(0, sbio->bio);
601
602 return 0;
603}
604
605static int scrub_page(struct scrub_dev *sdev, u64 logical, u64 len,
606 u64 physical, u64 flags, u64 gen, u64 mirror_num,
607 u8 *csum, int force)
608{
609 struct scrub_bio *sbio;
610
611again:
612 /*
613 * grab a fresh bio or wait for one to become available
614 */
615 while (sdev->curr == -1) {
616 spin_lock(&sdev->list_lock);
617 sdev->curr = sdev->first_free;
618 if (sdev->curr != -1) {
619 sdev->first_free = sdev->bios[sdev->curr]->next_free;
620 sdev->bios[sdev->curr]->next_free = -1;
621 sdev->bios[sdev->curr]->count = 0;
622 spin_unlock(&sdev->list_lock);
623 } else {
624 spin_unlock(&sdev->list_lock);
625 wait_event(sdev->list_wait, sdev->first_free != -1);
626 }
627 }
628 sbio = sdev->bios[sdev->curr];
629 if (sbio->count == 0) {
630 sbio->physical = physical;
631 sbio->logical = logical;
632 } else if (sbio->physical + sbio->count * PAGE_SIZE != physical) {
633 scrub_submit(sdev);
634 goto again;
635 }
636 sbio->spag[sbio->count].flags = flags;
637 sbio->spag[sbio->count].generation = gen;
638 sbio->spag[sbio->count].have_csum = 0;
639 sbio->spag[sbio->count].mirror_num = mirror_num;
640 if (csum) {
641 sbio->spag[sbio->count].have_csum = 1;
642 memcpy(sbio->spag[sbio->count].csum, csum, sdev->csum_size);
643 }
644 ++sbio->count;
645 if (sbio->count == SCRUB_PAGES_PER_BIO || force)
646 scrub_submit(sdev);
647
648 return 0;
649}
650
651static int scrub_find_csum(struct scrub_dev *sdev, u64 logical, u64 len,
652 u8 *csum)
653{
654 struct btrfs_ordered_sum *sum = NULL;
655 int ret = 0;
656 unsigned long i;
657 unsigned long num_sectors;
658 u32 sectorsize = sdev->dev->dev_root->sectorsize;
659
660 while (!list_empty(&sdev->csum_list)) {
661 sum = list_first_entry(&sdev->csum_list,
662 struct btrfs_ordered_sum, list);
663 if (sum->bytenr > logical)
664 return 0;
665 if (sum->bytenr + sum->len > logical)
666 break;
667
668 ++sdev->stat.csum_discards;
669 list_del(&sum->list);
670 kfree(sum);
671 sum = NULL;
672 }
673 if (!sum)
674 return 0;
675
676 num_sectors = sum->len / sectorsize;
677 for (i = 0; i < num_sectors; ++i) {
678 if (sum->sums[i].bytenr == logical) {
679 memcpy(csum, &sum->sums[i].sum, sdev->csum_size);
680 ret = 1;
681 break;
682 }
683 }
684 if (ret && i == num_sectors - 1) {
685 list_del(&sum->list);
686 kfree(sum);
687 }
688 return ret;
689}
690
691/* scrub extent tries to collect up to 64 kB for each bio */
692static int scrub_extent(struct scrub_dev *sdev, u64 logical, u64 len,
693 u64 physical, u64 flags, u64 gen, u64 mirror_num)
694{
695 int ret;
696 u8 csum[BTRFS_CSUM_SIZE];
697
698 while (len) {
699 u64 l = min_t(u64, len, PAGE_SIZE);
700 int have_csum = 0;
701
702 if (flags & BTRFS_EXTENT_FLAG_DATA) {
703 /* push csums to sbio */
704 have_csum = scrub_find_csum(sdev, logical, l, csum);
705 if (have_csum == 0)
706 ++sdev->stat.no_csum;
707 }
708 ret = scrub_page(sdev, logical, l, physical, flags, gen,
709 mirror_num, have_csum ? csum : NULL, 0);
710 if (ret)
711 return ret;
712 len -= l;
713 logical += l;
714 physical += l;
715 }
716 return 0;
717}
718
719static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev,
720 struct map_lookup *map, int num, u64 base, u64 length)
721{
722 struct btrfs_path *path;
723 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
724 struct btrfs_root *root = fs_info->extent_root;
725 struct btrfs_root *csum_root = fs_info->csum_root;
726 struct btrfs_extent_item *extent;
727 u64 flags;
728 int ret;
729 int slot;
730 int i;
731 u64 nstripes;
732 int start_stripe;
733 struct extent_buffer *l;
734 struct btrfs_key key;
735 u64 physical;
736 u64 logical;
737 u64 generation;
738 u64 mirror_num;
739
740 u64 increment = map->stripe_len;
741 u64 offset;
742
743 nstripes = length;
744 offset = 0;
745 do_div(nstripes, map->stripe_len);
746 if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
747 offset = map->stripe_len * num;
748 increment = map->stripe_len * map->num_stripes;
749 mirror_num = 0;
750 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
751 int factor = map->num_stripes / map->sub_stripes;
752 offset = map->stripe_len * (num / map->sub_stripes);
753 increment = map->stripe_len * factor;
754 mirror_num = num % map->sub_stripes;
755 } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
756 increment = map->stripe_len;
757 mirror_num = num % map->num_stripes;
758 } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
759 increment = map->stripe_len;
760 mirror_num = num % map->num_stripes;
761 } else {
762 increment = map->stripe_len;
763 mirror_num = 0;
764 }
765
766 path = btrfs_alloc_path();
767 if (!path)
768 return -ENOMEM;
769
770 path->reada = 2;
771 path->search_commit_root = 1;
772 path->skip_locking = 1;
773
774 /*
775 * find all extents for each stripe and just read them to get
776 * them into the page cache
777 * FIXME: we can do better. build a more intelligent prefetching
778 */
779 logical = base + offset;
780 physical = map->stripes[num].physical;
781 ret = 0;
782 for (i = 0; i < nstripes; ++i) {
783 key.objectid = logical;
784 key.type = BTRFS_EXTENT_ITEM_KEY;
785 key.offset = (u64)0;
786
787 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
788 if (ret < 0)
789 goto out;
790
791 l = path->nodes[0];
792 slot = path->slots[0];
793 btrfs_item_key_to_cpu(l, &key, slot);
794 if (key.objectid != logical) {
795 ret = btrfs_previous_item(root, path, 0,
796 BTRFS_EXTENT_ITEM_KEY);
797 if (ret < 0)
798 goto out;
799 }
800
801 while (1) {
802 l = path->nodes[0];
803 slot = path->slots[0];
804 if (slot >= btrfs_header_nritems(l)) {
805 ret = btrfs_next_leaf(root, path);
806 if (ret == 0)
807 continue;
808 if (ret < 0)
809 goto out;
810
811 break;
812 }
813 btrfs_item_key_to_cpu(l, &key, slot);
814
815 if (key.objectid >= logical + map->stripe_len)
816 break;
817
818 path->slots[0]++;
819 }
820 btrfs_release_path(root, path);
821 logical += increment;
822 physical += map->stripe_len;
823 cond_resched();
824 }
825
826 /*
827 * collect all data csums for the stripe to avoid seeking during
828 * the scrub. This might currently (crc32) end up to be about 1MB
829 */
830 start_stripe = 0;
831again:
832 logical = base + offset + start_stripe * increment;
833 for (i = start_stripe; i < nstripes; ++i) {
834 ret = btrfs_lookup_csums_range(csum_root, logical,
835 logical + map->stripe_len - 1,
836 &sdev->csum_list, 1);
837 if (ret)
838 goto out;
839
840 logical += increment;
841 cond_resched();
842 }
843 /*
844 * now find all extents for each stripe and scrub them
845 */
846 logical = base + offset + start_stripe * increment;
847 physical = map->stripes[num].physical + start_stripe * map->stripe_len;
848 ret = 0;
849 for (i = start_stripe; i < nstripes; ++i) {
850 /*
851 * canceled?
852 */
853 if (atomic_read(&fs_info->scrub_cancel_req) ||
854 atomic_read(&sdev->cancel_req)) {
855 ret = -ECANCELED;
856 goto out;
857 }
858 /*
859 * check to see if we have to pause
860 */
861 if (atomic_read(&fs_info->scrub_pause_req)) {
862 /* push queued extents */
863 scrub_submit(sdev);
864 wait_event(sdev->list_wait,
865 atomic_read(&sdev->in_flight) == 0);
866 atomic_inc(&fs_info->scrubs_paused);
867 wake_up(&fs_info->scrub_pause_wait);
868 mutex_lock(&fs_info->scrub_lock);
869 while (atomic_read(&fs_info->scrub_pause_req)) {
870 mutex_unlock(&fs_info->scrub_lock);
871 wait_event(fs_info->scrub_pause_wait,
872 atomic_read(&fs_info->scrub_pause_req) == 0);
873 mutex_lock(&fs_info->scrub_lock);
874 }
875 atomic_dec(&fs_info->scrubs_paused);
876 mutex_unlock(&fs_info->scrub_lock);
877 wake_up(&fs_info->scrub_pause_wait);
878 scrub_free_csums(sdev);
879 start_stripe = i;
880 goto again;
881 }
882
883 key.objectid = logical;
884 key.type = BTRFS_EXTENT_ITEM_KEY;
885 key.offset = (u64)0;
886
887 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
888 if (ret < 0)
889 goto out;
890
891 l = path->nodes[0];
892 slot = path->slots[0];
893 btrfs_item_key_to_cpu(l, &key, slot);
894 if (key.objectid != logical) {
895 ret = btrfs_previous_item(root, path, 0,
896 BTRFS_EXTENT_ITEM_KEY);
897 if (ret < 0)
898 goto out;
899 }
900
901 while (1) {
902 l = path->nodes[0];
903 slot = path->slots[0];
904 if (slot >= btrfs_header_nritems(l)) {
905 ret = btrfs_next_leaf(root, path);
906 if (ret == 0)
907 continue;
908 if (ret < 0)
909 goto out;
910
911 break;
912 }
913 btrfs_item_key_to_cpu(l, &key, slot);
914
915 if (key.objectid + key.offset <= logical)
916 goto next;
917
918 if (key.objectid >= logical + map->stripe_len)
919 break;
920
921 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY)
922 goto next;
923
924 extent = btrfs_item_ptr(l, slot,
925 struct btrfs_extent_item);
926 flags = btrfs_extent_flags(l, extent);
927 generation = btrfs_extent_generation(l, extent);
928
929 if (key.objectid < logical &&
930 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) {
931 printk(KERN_ERR
932 "btrfs scrub: tree block %llu spanning "
933 "stripes, ignored. logical=%llu\n",
934 (unsigned long long)key.objectid,
935 (unsigned long long)logical);
936 goto next;
937 }
938
939 /*
940 * trim extent to this stripe
941 */
942 if (key.objectid < logical) {
943 key.offset -= logical - key.objectid;
944 key.objectid = logical;
945 }
946 if (key.objectid + key.offset >
947 logical + map->stripe_len) {
948 key.offset = logical + map->stripe_len -
949 key.objectid;
950 }
951
952 ret = scrub_extent(sdev, key.objectid, key.offset,
953 key.objectid - logical + physical,
954 flags, generation, mirror_num);
955 if (ret)
956 goto out;
957
958next:
959 path->slots[0]++;
960 }
961 btrfs_release_path(root, path);
962 logical += increment;
963 physical += map->stripe_len;
964 spin_lock(&sdev->stat_lock);
965 sdev->stat.last_physical = physical;
966 spin_unlock(&sdev->stat_lock);
967 }
968 /* push queued extents */
969 scrub_submit(sdev);
970
971out:
972 btrfs_free_path(path);
973 return ret < 0 ? ret : 0;
974}
975
976static noinline_for_stack int scrub_chunk(struct scrub_dev *sdev,
977 u64 chunk_tree, u64 chunk_objectid, u64 chunk_offset, u64 length)
978{
979 struct btrfs_mapping_tree *map_tree =
980 &sdev->dev->dev_root->fs_info->mapping_tree;
981 struct map_lookup *map;
982 struct extent_map *em;
983 int i;
984 int ret = -EINVAL;
985
986 read_lock(&map_tree->map_tree.lock);
987 em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
988 read_unlock(&map_tree->map_tree.lock);
989
990 if (!em)
991 return -EINVAL;
992
993 map = (struct map_lookup *)em->bdev;
994 if (em->start != chunk_offset)
995 goto out;
996
997 if (em->len < length)
998 goto out;
999
1000 for (i = 0; i < map->num_stripes; ++i) {
1001 if (map->stripes[i].dev == sdev->dev) {
1002 ret = scrub_stripe(sdev, map, i, chunk_offset, length);
1003 if (ret)
1004 goto out;
1005 }
1006 }
1007out:
1008 free_extent_map(em);
1009
1010 return ret;
1011}
1012
1013static noinline_for_stack
1014int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end)
1015{
1016 struct btrfs_dev_extent *dev_extent = NULL;
1017 struct btrfs_path *path;
1018 struct btrfs_root *root = sdev->dev->dev_root;
1019 struct btrfs_fs_info *fs_info = root->fs_info;
1020 u64 length;
1021 u64 chunk_tree;
1022 u64 chunk_objectid;
1023 u64 chunk_offset;
1024 int ret;
1025 int slot;
1026 struct extent_buffer *l;
1027 struct btrfs_key key;
1028 struct btrfs_key found_key;
1029 struct btrfs_block_group_cache *cache;
1030
1031 path = btrfs_alloc_path();
1032 if (!path)
1033 return -ENOMEM;
1034
1035 path->reada = 2;
1036 path->search_commit_root = 1;
1037 path->skip_locking = 1;
1038
1039 key.objectid = sdev->dev->devid;
1040 key.offset = 0ull;
1041 key.type = BTRFS_DEV_EXTENT_KEY;
1042
1043
1044 while (1) {
1045 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1046 if (ret < 0)
1047 goto out;
1048 ret = 0;
1049
1050 l = path->nodes[0];
1051 slot = path->slots[0];
1052
1053 btrfs_item_key_to_cpu(l, &found_key, slot);
1054
1055 if (found_key.objectid != sdev->dev->devid)
1056 break;
1057
1058 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
1059 break;
1060
1061 if (found_key.offset >= end)
1062 break;
1063
1064 if (found_key.offset < key.offset)
1065 break;
1066
1067 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1068 length = btrfs_dev_extent_length(l, dev_extent);
1069
1070 if (found_key.offset + length <= start) {
1071 key.offset = found_key.offset + length;
1072 btrfs_release_path(root, path);
1073 continue;
1074 }
1075
1076 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
1077 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
1078 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
1079
1080 /*
1081 * get a reference on the corresponding block group to prevent
1082 * the chunk from going away while we scrub it
1083 */
1084 cache = btrfs_lookup_block_group(fs_info, chunk_offset);
1085 if (!cache) {
1086 ret = -ENOENT;
1087 goto out;
1088 }
1089 ret = scrub_chunk(sdev, chunk_tree, chunk_objectid,
1090 chunk_offset, length);
1091 btrfs_put_block_group(cache);
1092 if (ret)
1093 break;
1094
1095 key.offset = found_key.offset + length;
1096 btrfs_release_path(root, path);
1097 }
1098
1099out:
1100 btrfs_free_path(path);
1101 return ret;
1102}
1103
1104static noinline_for_stack int scrub_supers(struct scrub_dev *sdev)
1105{
1106 int i;
1107 u64 bytenr;
1108 u64 gen;
1109 int ret;
1110 struct btrfs_device *device = sdev->dev;
1111 struct btrfs_root *root = device->dev_root;
1112
1113 gen = root->fs_info->last_trans_committed;
1114
1115 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
1116 bytenr = btrfs_sb_offset(i);
1117 if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
1118 break;
1119
1120 ret = scrub_page(sdev, bytenr, PAGE_SIZE, bytenr,
1121 BTRFS_EXTENT_FLAG_SUPER, gen, i, NULL, 1);
1122 if (ret)
1123 return ret;
1124 }
1125 wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
1126
1127 return 0;
1128}
1129
1130/*
1131 * get a reference count on fs_info->scrub_workers. start worker if necessary
1132 */
1133static noinline_for_stack int scrub_workers_get(struct btrfs_root *root)
1134{
1135 struct btrfs_fs_info *fs_info = root->fs_info;
1136
1137 mutex_lock(&fs_info->scrub_lock);
1138 if (fs_info->scrub_workers_refcnt == 0)
1139 btrfs_start_workers(&fs_info->scrub_workers, 1);
1140 ++fs_info->scrub_workers_refcnt;
1141 mutex_unlock(&fs_info->scrub_lock);
1142
1143 return 0;
1144}
1145
1146static noinline_for_stack void scrub_workers_put(struct btrfs_root *root)
1147{
1148 struct btrfs_fs_info *fs_info = root->fs_info;
1149
1150 mutex_lock(&fs_info->scrub_lock);
1151 if (--fs_info->scrub_workers_refcnt == 0)
1152 btrfs_stop_workers(&fs_info->scrub_workers);
1153 WARN_ON(fs_info->scrub_workers_refcnt < 0);
1154 mutex_unlock(&fs_info->scrub_lock);
1155}
1156
1157
1158int btrfs_scrub_dev(struct btrfs_root *root, u64 devid, u64 start, u64 end,
1159 struct btrfs_scrub_progress *progress)
1160{
1161 struct scrub_dev *sdev;
1162 struct btrfs_fs_info *fs_info = root->fs_info;
1163 int ret;
1164 struct btrfs_device *dev;
1165
1166 if (root->fs_info->closing)
1167 return -EINVAL;
1168
1169 /*
1170 * check some assumptions
1171 */
1172 if (root->sectorsize != PAGE_SIZE ||
1173 root->sectorsize != root->leafsize ||
1174 root->sectorsize != root->nodesize) {
1175 printk(KERN_ERR "btrfs_scrub: size assumptions fail\n");
1176 return -EINVAL;
1177 }
1178
1179 ret = scrub_workers_get(root);
1180 if (ret)
1181 return ret;
1182
1183 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1184 dev = btrfs_find_device(root, devid, NULL, NULL);
1185 if (!dev || dev->missing) {
1186 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1187 scrub_workers_put(root);
1188 return -ENODEV;
1189 }
1190 mutex_lock(&fs_info->scrub_lock);
1191
1192 if (!dev->in_fs_metadata) {
1193 mutex_unlock(&fs_info->scrub_lock);
1194 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1195 scrub_workers_put(root);
1196 return -ENODEV;
1197 }
1198
1199 if (dev->scrub_device) {
1200 mutex_unlock(&fs_info->scrub_lock);
1201 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1202 scrub_workers_put(root);
1203 return -EINPROGRESS;
1204 }
1205 sdev = scrub_setup_dev(dev);
1206 if (IS_ERR(sdev)) {
1207 mutex_unlock(&fs_info->scrub_lock);
1208 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1209 scrub_workers_put(root);
1210 return PTR_ERR(sdev);
1211 }
1212 dev->scrub_device = sdev;
1213
1214 atomic_inc(&fs_info->scrubs_running);
1215 mutex_unlock(&fs_info->scrub_lock);
1216 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1217
1218 down_read(&fs_info->scrub_super_lock);
1219 ret = scrub_supers(sdev);
1220 up_read(&fs_info->scrub_super_lock);
1221
1222 if (!ret)
1223 ret = scrub_enumerate_chunks(sdev, start, end);
1224
1225 wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
1226
1227 atomic_dec(&fs_info->scrubs_running);
1228 wake_up(&fs_info->scrub_pause_wait);
1229
1230 if (progress)
1231 memcpy(progress, &sdev->stat, sizeof(*progress));
1232
1233 mutex_lock(&fs_info->scrub_lock);
1234 dev->scrub_device = NULL;
1235 mutex_unlock(&fs_info->scrub_lock);
1236
1237 scrub_free_dev(sdev);
1238 scrub_workers_put(root);
1239
1240 return ret;
1241}
1242
1243int btrfs_scrub_pause(struct btrfs_root *root)
1244{
1245 struct btrfs_fs_info *fs_info = root->fs_info;
1246
1247 mutex_lock(&fs_info->scrub_lock);
1248 atomic_inc(&fs_info->scrub_pause_req);
1249 while (atomic_read(&fs_info->scrubs_paused) !=
1250 atomic_read(&fs_info->scrubs_running)) {
1251 mutex_unlock(&fs_info->scrub_lock);
1252 wait_event(fs_info->scrub_pause_wait,
1253 atomic_read(&fs_info->scrubs_paused) ==
1254 atomic_read(&fs_info->scrubs_running));
1255 mutex_lock(&fs_info->scrub_lock);
1256 }
1257 mutex_unlock(&fs_info->scrub_lock);
1258
1259 return 0;
1260}
1261
1262int btrfs_scrub_continue(struct btrfs_root *root)
1263{
1264 struct btrfs_fs_info *fs_info = root->fs_info;
1265
1266 atomic_dec(&fs_info->scrub_pause_req);
1267 wake_up(&fs_info->scrub_pause_wait);
1268 return 0;
1269}
1270
1271int btrfs_scrub_pause_super(struct btrfs_root *root)
1272{
1273 down_write(&root->fs_info->scrub_super_lock);
1274 return 0;
1275}
1276
1277int btrfs_scrub_continue_super(struct btrfs_root *root)
1278{
1279 up_write(&root->fs_info->scrub_super_lock);
1280 return 0;
1281}
1282
1283int btrfs_scrub_cancel(struct btrfs_root *root)
1284{
1285 struct btrfs_fs_info *fs_info = root->fs_info;
1286
1287 mutex_lock(&fs_info->scrub_lock);
1288 if (!atomic_read(&fs_info->scrubs_running)) {
1289 mutex_unlock(&fs_info->scrub_lock);
1290 return -ENOTCONN;
1291 }
1292
1293 atomic_inc(&fs_info->scrub_cancel_req);
1294 while (atomic_read(&fs_info->scrubs_running)) {
1295 mutex_unlock(&fs_info->scrub_lock);
1296 wait_event(fs_info->scrub_pause_wait,
1297 atomic_read(&fs_info->scrubs_running) == 0);
1298 mutex_lock(&fs_info->scrub_lock);
1299 }
1300 atomic_dec(&fs_info->scrub_cancel_req);
1301 mutex_unlock(&fs_info->scrub_lock);
1302
1303 return 0;
1304}
1305
1306int btrfs_scrub_cancel_dev(struct btrfs_root *root, struct btrfs_device *dev)
1307{
1308 struct btrfs_fs_info *fs_info = root->fs_info;
1309 struct scrub_dev *sdev;
1310
1311 mutex_lock(&fs_info->scrub_lock);
1312 sdev = dev->scrub_device;
1313 if (!sdev) {
1314 mutex_unlock(&fs_info->scrub_lock);
1315 return -ENOTCONN;
1316 }
1317 atomic_inc(&sdev->cancel_req);
1318 while (dev->scrub_device) {
1319 mutex_unlock(&fs_info->scrub_lock);
1320 wait_event(fs_info->scrub_pause_wait,
1321 dev->scrub_device == NULL);
1322 mutex_lock(&fs_info->scrub_lock);
1323 }
1324 mutex_unlock(&fs_info->scrub_lock);
1325
1326 return 0;
1327}
1328int btrfs_scrub_cancel_devid(struct btrfs_root *root, u64 devid)
1329{
1330 struct btrfs_fs_info *fs_info = root->fs_info;
1331 struct btrfs_device *dev;
1332 int ret;
1333
1334 /*
1335 * we have to hold the device_list_mutex here so the device
1336 * does not go away in cancel_dev. FIXME: find a better solution
1337 */
1338 mutex_lock(&fs_info->fs_devices->device_list_mutex);
1339 dev = btrfs_find_device(root, devid, NULL, NULL);
1340 if (!dev) {
1341 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1342 return -ENODEV;
1343 }
1344 ret = btrfs_scrub_cancel_dev(root, dev);
1345 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1346
1347 return ret;
1348}
1349
1350int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
1351 struct btrfs_scrub_progress *progress)
1352{
1353 struct btrfs_device *dev;
1354 struct scrub_dev *sdev = NULL;
1355
1356 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1357 dev = btrfs_find_device(root, devid, NULL, NULL);
1358 if (dev)
1359 sdev = dev->scrub_device;
1360 if (sdev)
1361 memcpy(progress, &sdev->stat, sizeof(*progress));
1362 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1363
1364 return dev ? (sdev ? 0 : -ENOTCONN) : -ENODEV;
1365}
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