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MIPS: sb1250: Restore dropped irq_mask function
[linux-2.6/linux-mips.git] / fs / btrfs / scrub.c
blobdf50fd1eca8f46cbd7eed9f4a1f52ca87b64aa8f
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 mode to also read unallocated space
46 * - make the prefetch cancellable
47 */
48
49 struct scrub_bio;
50 struct scrub_page;
51 struct scrub_dev;
52 static void scrub_bio_end_io(struct bio *bio, int err);
53 static void scrub_checksum(struct btrfs_work *work);
54 static int scrub_checksum_data(struct scrub_dev *sdev,
55 struct scrub_page *spag, void *buffer);
56 static int scrub_checksum_tree_block(struct scrub_dev *sdev,
57 struct scrub_page *spag, u64 logical,
58 void *buffer);
59 static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer);
60 static int scrub_fixup_check(struct scrub_bio *sbio, int ix);
61 static void scrub_fixup_end_io(struct bio *bio, int err);
62 static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector,
63 struct page *page);
64 static void scrub_fixup(struct scrub_bio *sbio, int ix);
65
66 #define SCRUB_PAGES_PER_BIO 16 /* 64k per bio */
67 #define SCRUB_BIOS_PER_DEV 16 /* 1 MB per device in flight */
68
69 struct scrub_page {
70 u64 flags; /* extent flags */
71 u64 generation;
72 u64 mirror_num;
73 int have_csum;
74 u8 csum[BTRFS_CSUM_SIZE];
75 };
76
77 struct scrub_bio {
78 int index;
79 struct scrub_dev *sdev;
80 struct bio *bio;
81 int err;
82 u64 logical;
83 u64 physical;
84 struct scrub_page spag[SCRUB_PAGES_PER_BIO];
85 u64 count;
86 int next_free;
87 struct btrfs_work work;
88 };
89
90 struct scrub_dev {
91 struct scrub_bio *bios[SCRUB_BIOS_PER_DEV];
92 struct btrfs_device *dev;
93 int first_free;
94 int curr;
95 atomic_t in_flight;
96 spinlock_t list_lock;
97 wait_queue_head_t list_wait;
98 u16 csum_size;
99 struct list_head csum_list;
100 atomic_t cancel_req;
101 int readonly;
102 /*
103 * statistics
104 */
105 struct btrfs_scrub_progress stat;
106 spinlock_t stat_lock;
107 };
108
109 static 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
120 static void scrub_free_bio(struct bio *bio)
121 {
122 int i;
123 struct page *last_page = NULL;
124
125 if (!bio)
126 return;
127
128 for (i = 0; i < bio->bi_vcnt; ++i) {
129 if (bio->bi_io_vec[i].bv_page == last_page)
130 continue;
131 last_page = bio->bi_io_vec[i].bv_page;
132 __free_page(last_page);
133 }
134 bio_put(bio);
135 }
136
137 static noinline_for_stack void scrub_free_dev(struct scrub_dev *sdev)
138 {
139 int i;
140
141 if (!sdev)
142 return;
143
144 for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
145 struct scrub_bio *sbio = sdev->bios[i];
146
147 if (!sbio)
148 break;
149
150 scrub_free_bio(sbio->bio);
151 kfree(sbio);
152 }
153
154 scrub_free_csums(sdev);
155 kfree(sdev);
156 }
157
158 static noinline_for_stack
159 struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev)
160 {
161 struct scrub_dev *sdev;
162 int i;
163 struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
164
165 sdev = kzalloc(sizeof(*sdev), GFP_NOFS);
166 if (!sdev)
167 goto nomem;
168 sdev->dev = dev;
169 for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
170 struct scrub_bio *sbio;
171
172 sbio = kzalloc(sizeof(*sbio), GFP_NOFS);
173 if (!sbio)
174 goto nomem;
175 sdev->bios[i] = sbio;
176
177 sbio->index = i;
178 sbio->sdev = sdev;
179 sbio->count = 0;
180 sbio->work.func = scrub_checksum;
181
182 if (i != SCRUB_BIOS_PER_DEV-1)
183 sdev->bios[i]->next_free = i + 1;
184 else
185 sdev->bios[i]->next_free = -1;
186 }
187 sdev->first_free = 0;
188 sdev->curr = -1;
189 atomic_set(&sdev->in_flight, 0);
190 atomic_set(&sdev->cancel_req, 0);
191 sdev->csum_size = btrfs_super_csum_size(&fs_info->super_copy);
192 INIT_LIST_HEAD(&sdev->csum_list);
193
194 spin_lock_init(&sdev->list_lock);
195 spin_lock_init(&sdev->stat_lock);
196 init_waitqueue_head(&sdev->list_wait);
197 return sdev;
198
199 nomem:
200 scrub_free_dev(sdev);
201 return ERR_PTR(-ENOMEM);
202 }
203
204 /*
205 * scrub_recheck_error gets called when either verification of the page
206 * failed or the bio failed to read, e.g. with EIO. In the latter case,
207 * recheck_error gets called for every page in the bio, even though only
208 * one may be bad
209 */
210 static void scrub_recheck_error(struct scrub_bio *sbio, int ix)
211 {
212 if (sbio->err) {
213 if (scrub_fixup_io(READ, sbio->sdev->dev->bdev,
214 (sbio->physical + ix * PAGE_SIZE) >> 9,
215 sbio->bio->bi_io_vec[ix].bv_page) == 0) {
216 if (scrub_fixup_check(sbio, ix) == 0)
217 return;
218 }
219 }
220
221 scrub_fixup(sbio, ix);
222 }
223
224 static int scrub_fixup_check(struct scrub_bio *sbio, int ix)
225 {
226 int ret = 1;
227 struct page *page;
228 void *buffer;
229 u64 flags = sbio->spag[ix].flags;
230
231 page = sbio->bio->bi_io_vec[ix].bv_page;
232 buffer = kmap_atomic(page, KM_USER0);
233 if (flags & BTRFS_EXTENT_FLAG_DATA) {
234 ret = scrub_checksum_data(sbio->sdev,
235 sbio->spag + ix, buffer);
236 } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
237 ret = scrub_checksum_tree_block(sbio->sdev,
238 sbio->spag + ix,
239 sbio->logical + ix * PAGE_SIZE,
240 buffer);
241 } else {
242 WARN_ON(1);
243 }
244 kunmap_atomic(buffer, KM_USER0);
245
246 return ret;
247 }
248
249 static void scrub_fixup_end_io(struct bio *bio, int err)
250 {
251 complete((struct completion *)bio->bi_private);
252 }
253
254 static void scrub_fixup(struct scrub_bio *sbio, int ix)
255 {
256 struct scrub_dev *sdev = sbio->sdev;
257 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
258 struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
259 struct btrfs_multi_bio *multi = NULL;
260 u64 logical = sbio->logical + ix * PAGE_SIZE;
261 u64 length;
262 int i;
263 int ret;
264 DECLARE_COMPLETION_ONSTACK(complete);
265
266 if ((sbio->spag[ix].flags & BTRFS_EXTENT_FLAG_DATA) &&
267 (sbio->spag[ix].have_csum == 0)) {
268 /*
269 * nodatasum, don't try to fix anything
270 * FIXME: we can do better, open the inode and trigger a
271 * writeback
272 */
273 goto uncorrectable;
274 }
275
276 length = PAGE_SIZE;
277 ret = btrfs_map_block(map_tree, REQ_WRITE, logical, &length,
278 &multi, 0);
279 if (ret || !multi || length < PAGE_SIZE) {
280 printk(KERN_ERR
281 "scrub_fixup: btrfs_map_block failed us for %llu\n",
282 (unsigned long long)logical);
283 WARN_ON(1);
284 return;
285 }
286
287 if (multi->num_stripes == 1)
288 /* there aren't any replicas */
289 goto uncorrectable;
290
291 /*
292 * first find a good copy
293 */
294 for (i = 0; i < multi->num_stripes; ++i) {
295 if (i == sbio->spag[ix].mirror_num)
296 continue;
297
298 if (scrub_fixup_io(READ, multi->stripes[i].dev->bdev,
299 multi->stripes[i].physical >> 9,
300 sbio->bio->bi_io_vec[ix].bv_page)) {
301 /* I/O-error, this is not a good copy */
302 continue;
303 }
304
305 if (scrub_fixup_check(sbio, ix) == 0)
306 break;
307 }
308 if (i == multi->num_stripes)
309 goto uncorrectable;
310
311 if (!sdev->readonly) {
312 /*
313 * bi_io_vec[ix].bv_page now contains good data, write it back
314 */
315 if (scrub_fixup_io(WRITE, sdev->dev->bdev,
316 (sbio->physical + ix * PAGE_SIZE) >> 9,
317 sbio->bio->bi_io_vec[ix].bv_page)) {
318 /* I/O-error, writeback failed, give up */
319 goto uncorrectable;
320 }
321 }
322
323 kfree(multi);
324 spin_lock(&sdev->stat_lock);
325 ++sdev->stat.corrected_errors;
326 spin_unlock(&sdev->stat_lock);
327
328 if (printk_ratelimit())
329 printk(KERN_ERR "btrfs: fixed up at %llu\n",
330 (unsigned long long)logical);
331 return;
332
333 uncorrectable:
334 kfree(multi);
335 spin_lock(&sdev->stat_lock);
336 ++sdev->stat.uncorrectable_errors;
337 spin_unlock(&sdev->stat_lock);
338
339 if (printk_ratelimit())
340 printk(KERN_ERR "btrfs: unable to fixup at %llu\n",
341 (unsigned long long)logical);
342 }
343
344 static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector,
345 struct page *page)
346 {
347 struct bio *bio = NULL;
348 int ret;
349 DECLARE_COMPLETION_ONSTACK(complete);
350
351 bio = bio_alloc(GFP_NOFS, 1);
352 bio->bi_bdev = bdev;
353 bio->bi_sector = sector;
354 bio_add_page(bio, page, PAGE_SIZE, 0);
355 bio->bi_end_io = scrub_fixup_end_io;
356 bio->bi_private = &complete;
357 submit_bio(rw, bio);
358
359 /* this will also unplug the queue */
360 wait_for_completion(&complete);
361
362 ret = !test_bit(BIO_UPTODATE, &bio->bi_flags);
363 bio_put(bio);
364 return ret;
365 }
366
367 static void scrub_bio_end_io(struct bio *bio, int err)
368 {
369 struct scrub_bio *sbio = bio->bi_private;
370 struct scrub_dev *sdev = sbio->sdev;
371 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
372
373 sbio->err = err;
374 sbio->bio = bio;
375
376 btrfs_queue_worker(&fs_info->scrub_workers, &sbio->work);
377 }
378
379 static void scrub_checksum(struct btrfs_work *work)
380 {
381 struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
382 struct scrub_dev *sdev = sbio->sdev;
383 struct page *page;
384 void *buffer;
385 int i;
386 u64 flags;
387 u64 logical;
388 int ret;
389
390 if (sbio->err) {
391 for (i = 0; i < sbio->count; ++i)
392 scrub_recheck_error(sbio, i);
393
394 sbio->bio->bi_flags &= ~(BIO_POOL_MASK - 1);
395 sbio->bio->bi_flags |= 1 << BIO_UPTODATE;
396 sbio->bio->bi_phys_segments = 0;
397 sbio->bio->bi_idx = 0;
398
399 for (i = 0; i < sbio->count; i++) {
400 struct bio_vec *bi;
401 bi = &sbio->bio->bi_io_vec[i];
402 bi->bv_offset = 0;
403 bi->bv_len = PAGE_SIZE;
404 }
405
406 spin_lock(&sdev->stat_lock);
407 ++sdev->stat.read_errors;
408 spin_unlock(&sdev->stat_lock);
409 goto out;
410 }
411 for (i = 0; i < sbio->count; ++i) {
412 page = sbio->bio->bi_io_vec[i].bv_page;
413 buffer = kmap_atomic(page, KM_USER0);
414 flags = sbio->spag[i].flags;
415 logical = sbio->logical + i * PAGE_SIZE;
416 ret = 0;
417 if (flags & BTRFS_EXTENT_FLAG_DATA) {
418 ret = scrub_checksum_data(sdev, sbio->spag + i, buffer);
419 } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
420 ret = scrub_checksum_tree_block(sdev, sbio->spag + i,
421 logical, buffer);
422 } else if (flags & BTRFS_EXTENT_FLAG_SUPER) {
423 BUG_ON(i);
424 (void)scrub_checksum_super(sbio, buffer);
425 } else {
426 WARN_ON(1);
427 }
428 kunmap_atomic(buffer, KM_USER0);
429 if (ret)
430 scrub_recheck_error(sbio, i);
431 }
432
433 out:
434 scrub_free_bio(sbio->bio);
435 sbio->bio = NULL;
436 spin_lock(&sdev->list_lock);
437 sbio->next_free = sdev->first_free;
438 sdev->first_free = sbio->index;
439 spin_unlock(&sdev->list_lock);
440 atomic_dec(&sdev->in_flight);
441 wake_up(&sdev->list_wait);
442 }
443
444 static int scrub_checksum_data(struct scrub_dev *sdev,
445 struct scrub_page *spag, void *buffer)
446 {
447 u8 csum[BTRFS_CSUM_SIZE];
448 u32 crc = ~(u32)0;
449 int fail = 0;
450 struct btrfs_root *root = sdev->dev->dev_root;
451
452 if (!spag->have_csum)
453 return 0;
454
455 crc = btrfs_csum_data(root, buffer, crc, PAGE_SIZE);
456 btrfs_csum_final(crc, csum);
457 if (memcmp(csum, spag->csum, sdev->csum_size))
458 fail = 1;
459
460 spin_lock(&sdev->stat_lock);
461 ++sdev->stat.data_extents_scrubbed;
462 sdev->stat.data_bytes_scrubbed += PAGE_SIZE;
463 if (fail)
464 ++sdev->stat.csum_errors;
465 spin_unlock(&sdev->stat_lock);
466
467 return fail;
468 }
469
470 static int scrub_checksum_tree_block(struct scrub_dev *sdev,
471 struct scrub_page *spag, u64 logical,
472 void *buffer)
473 {
474 struct btrfs_header *h;
475 struct btrfs_root *root = sdev->dev->dev_root;
476 struct btrfs_fs_info *fs_info = root->fs_info;
477 u8 csum[BTRFS_CSUM_SIZE];
478 u32 crc = ~(u32)0;
479 int fail = 0;
480 int crc_fail = 0;
481
482 /*
483 * we don't use the getter functions here, as we
484 * a) don't have an extent buffer and
485 * b) the page is already kmapped
486 */
487 h = (struct btrfs_header *)buffer;
488
489 if (logical != le64_to_cpu(h->bytenr))
490 ++fail;
491
492 if (spag->generation != le64_to_cpu(h->generation))
493 ++fail;
494
495 if (memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
496 ++fail;
497
498 if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
499 BTRFS_UUID_SIZE))
500 ++fail;
501
502 crc = btrfs_csum_data(root, buffer + BTRFS_CSUM_SIZE, crc,
503 PAGE_SIZE - BTRFS_CSUM_SIZE);
504 btrfs_csum_final(crc, csum);
505 if (memcmp(csum, h->csum, sdev->csum_size))
506 ++crc_fail;
507
508 spin_lock(&sdev->stat_lock);
509 ++sdev->stat.tree_extents_scrubbed;
510 sdev->stat.tree_bytes_scrubbed += PAGE_SIZE;
511 if (crc_fail)
512 ++sdev->stat.csum_errors;
513 if (fail)
514 ++sdev->stat.verify_errors;
515 spin_unlock(&sdev->stat_lock);
516
517 return fail || crc_fail;
518 }
519
520 static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer)
521 {
522 struct btrfs_super_block *s;
523 u64 logical;
524 struct scrub_dev *sdev = sbio->sdev;
525 struct btrfs_root *root = sdev->dev->dev_root;
526 struct btrfs_fs_info *fs_info = root->fs_info;
527 u8 csum[BTRFS_CSUM_SIZE];
528 u32 crc = ~(u32)0;
529 int fail = 0;
530
531 s = (struct btrfs_super_block *)buffer;
532 logical = sbio->logical;
533
534 if (logical != le64_to_cpu(s->bytenr))
535 ++fail;
536
537 if (sbio->spag[0].generation != le64_to_cpu(s->generation))
538 ++fail;
539
540 if (memcmp(s->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
541 ++fail;
542
543 crc = btrfs_csum_data(root, buffer + BTRFS_CSUM_SIZE, crc,
544 PAGE_SIZE - BTRFS_CSUM_SIZE);
545 btrfs_csum_final(crc, csum);
546 if (memcmp(csum, s->csum, sbio->sdev->csum_size))
547 ++fail;
548
549 if (fail) {
550 /*
551 * if we find an error in a super block, we just report it.
552 * They will get written with the next transaction commit
553 * anyway
554 */
555 spin_lock(&sdev->stat_lock);
556 ++sdev->stat.super_errors;
557 spin_unlock(&sdev->stat_lock);
558 }
559
560 return fail;
561 }
562
563 static int scrub_submit(struct scrub_dev *sdev)
564 {
565 struct scrub_bio *sbio;
566 struct bio *bio;
567 int i;
568
569 if (sdev->curr == -1)
570 return 0;
571
572 sbio = sdev->bios[sdev->curr];
573
574 bio = bio_alloc(GFP_NOFS, sbio->count);
575 if (!bio)
576 goto nomem;
577
578 bio->bi_private = sbio;
579 bio->bi_end_io = scrub_bio_end_io;
580 bio->bi_bdev = sdev->dev->bdev;
581 bio->bi_sector = sbio->physical >> 9;
582
583 for (i = 0; i < sbio->count; ++i) {
584 struct page *page;
585 int ret;
586
587 page = alloc_page(GFP_NOFS);
588 if (!page)
589 goto nomem;
590
591 ret = bio_add_page(bio, page, PAGE_SIZE, 0);
592 if (!ret) {
593 __free_page(page);
594 goto nomem;
595 }
596 }
597
598 sbio->err = 0;
599 sdev->curr = -1;
600 atomic_inc(&sdev->in_flight);
601
602 submit_bio(READ, bio);
603
604 return 0;
605
606 nomem:
607 scrub_free_bio(bio);
608
609 return -ENOMEM;
610 }
611
612 static int scrub_page(struct scrub_dev *sdev, u64 logical, u64 len,
613 u64 physical, u64 flags, u64 gen, u64 mirror_num,
614 u8 *csum, int force)
615 {
616 struct scrub_bio *sbio;
617
618 again:
619 /*
620 * grab a fresh bio or wait for one to become available
621 */
622 while (sdev->curr == -1) {
623 spin_lock(&sdev->list_lock);
624 sdev->curr = sdev->first_free;
625 if (sdev->curr != -1) {
626 sdev->first_free = sdev->bios[sdev->curr]->next_free;
627 sdev->bios[sdev->curr]->next_free = -1;
628 sdev->bios[sdev->curr]->count = 0;
629 spin_unlock(&sdev->list_lock);
630 } else {
631 spin_unlock(&sdev->list_lock);
632 wait_event(sdev->list_wait, sdev->first_free != -1);
633 }
634 }
635 sbio = sdev->bios[sdev->curr];
636 if (sbio->count == 0) {
637 sbio->physical = physical;
638 sbio->logical = logical;
639 } else if (sbio->physical + sbio->count * PAGE_SIZE != physical ||
640 sbio->logical + sbio->count * PAGE_SIZE != logical) {
641 int ret;
642
643 ret = scrub_submit(sdev);
644 if (ret)
645 return ret;
646 goto again;
647 }
648 sbio->spag[sbio->count].flags = flags;
649 sbio->spag[sbio->count].generation = gen;
650 sbio->spag[sbio->count].have_csum = 0;
651 sbio->spag[sbio->count].mirror_num = mirror_num;
652 if (csum) {
653 sbio->spag[sbio->count].have_csum = 1;
654 memcpy(sbio->spag[sbio->count].csum, csum, sdev->csum_size);
655 }
656 ++sbio->count;
657 if (sbio->count == SCRUB_PAGES_PER_BIO || force) {
658 int ret;
659
660 ret = scrub_submit(sdev);
661 if (ret)
662 return ret;
663 }
664
665 return 0;
666 }
667
668 static int scrub_find_csum(struct scrub_dev *sdev, u64 logical, u64 len,
669 u8 *csum)
670 {
671 struct btrfs_ordered_sum *sum = NULL;
672 int ret = 0;
673 unsigned long i;
674 unsigned long num_sectors;
675 u32 sectorsize = sdev->dev->dev_root->sectorsize;
676
677 while (!list_empty(&sdev->csum_list)) {
678 sum = list_first_entry(&sdev->csum_list,
679 struct btrfs_ordered_sum, list);
680 if (sum->bytenr > logical)
681 return 0;
682 if (sum->bytenr + sum->len > logical)
683 break;
684
685 ++sdev->stat.csum_discards;
686 list_del(&sum->list);
687 kfree(sum);
688 sum = NULL;
689 }
690 if (!sum)
691 return 0;
692
693 num_sectors = sum->len / sectorsize;
694 for (i = 0; i < num_sectors; ++i) {
695 if (sum->sums[i].bytenr == logical) {
696 memcpy(csum, &sum->sums[i].sum, sdev->csum_size);
697 ret = 1;
698 break;
699 }
700 }
701 if (ret && i == num_sectors - 1) {
702 list_del(&sum->list);
703 kfree(sum);
704 }
705 return ret;
706 }
707
708 /* scrub extent tries to collect up to 64 kB for each bio */
709 static int scrub_extent(struct scrub_dev *sdev, u64 logical, u64 len,
710 u64 physical, u64 flags, u64 gen, u64 mirror_num)
711 {
712 int ret;
713 u8 csum[BTRFS_CSUM_SIZE];
714
715 while (len) {
716 u64 l = min_t(u64, len, PAGE_SIZE);
717 int have_csum = 0;
718
719 if (flags & BTRFS_EXTENT_FLAG_DATA) {
720 /* push csums to sbio */
721 have_csum = scrub_find_csum(sdev, logical, l, csum);
722 if (have_csum == 0)
723 ++sdev->stat.no_csum;
724 }
725 ret = scrub_page(sdev, logical, l, physical, flags, gen,
726 mirror_num, have_csum ? csum : NULL, 0);
727 if (ret)
728 return ret;
729 len -= l;
730 logical += l;
731 physical += l;
732 }
733 return 0;
734 }
735
736 static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev,
737 struct map_lookup *map, int num, u64 base, u64 length)
738 {
739 struct btrfs_path *path;
740 struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
741 struct btrfs_root *root = fs_info->extent_root;
742 struct btrfs_root *csum_root = fs_info->csum_root;
743 struct btrfs_extent_item *extent;
744 struct blk_plug plug;
745 u64 flags;
746 int ret;
747 int slot;
748 int i;
749 u64 nstripes;
750 int start_stripe;
751 struct extent_buffer *l;
752 struct btrfs_key key;
753 u64 physical;
754 u64 logical;
755 u64 generation;
756 u64 mirror_num;
757
758 u64 increment = map->stripe_len;
759 u64 offset;
760
761 nstripes = length;
762 offset = 0;
763 do_div(nstripes, map->stripe_len);
764 if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
765 offset = map->stripe_len * num;
766 increment = map->stripe_len * map->num_stripes;
767 mirror_num = 0;
768 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
769 int factor = map->num_stripes / map->sub_stripes;
770 offset = map->stripe_len * (num / map->sub_stripes);
771 increment = map->stripe_len * factor;
772 mirror_num = num % map->sub_stripes;
773 } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
774 increment = map->stripe_len;
775 mirror_num = num % map->num_stripes;
776 } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
777 increment = map->stripe_len;
778 mirror_num = num % map->num_stripes;
779 } else {
780 increment = map->stripe_len;
781 mirror_num = 0;
782 }
783
784 path = btrfs_alloc_path();
785 if (!path)
786 return -ENOMEM;
787
788 path->reada = 2;
789 path->search_commit_root = 1;
790 path->skip_locking = 1;
791
792 /*
793 * find all extents for each stripe and just read them to get
794 * them into the page cache
795 * FIXME: we can do better. build a more intelligent prefetching
796 */
797 logical = base + offset;
798 physical = map->stripes[num].physical;
799 ret = 0;
800 for (i = 0; i < nstripes; ++i) {
801 key.objectid = logical;
802 key.type = BTRFS_EXTENT_ITEM_KEY;
803 key.offset = (u64)0;
804
805 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
806 if (ret < 0)
807 goto out;
808
809 l = path->nodes[0];
810 slot = path->slots[0];
811 btrfs_item_key_to_cpu(l, &key, slot);
812 if (key.objectid != logical) {
813 ret = btrfs_previous_item(root, path, 0,
814 BTRFS_EXTENT_ITEM_KEY);
815 if (ret < 0)
816 goto out;
817 }
818
819 while (1) {
820 l = path->nodes[0];
821 slot = path->slots[0];
822 if (slot >= btrfs_header_nritems(l)) {
823 ret = btrfs_next_leaf(root, path);
824 if (ret == 0)
825 continue;
826 if (ret < 0)
827 goto out;
828
829 break;
830 }
831 btrfs_item_key_to_cpu(l, &key, slot);
832
833 if (key.objectid >= logical + map->stripe_len)
834 break;
835
836 path->slots[0]++;
837 }
838 btrfs_release_path(path);
839 logical += increment;
840 physical += map->stripe_len;
841 cond_resched();
842 }
843
844 /*
845 * collect all data csums for the stripe to avoid seeking during
846 * the scrub. This might currently (crc32) end up to be about 1MB
847 */
848 start_stripe = 0;
849 blk_start_plug(&plug);
850 again:
851 logical = base + offset + start_stripe * increment;
852 for (i = start_stripe; i < nstripes; ++i) {
853 ret = btrfs_lookup_csums_range(csum_root, logical,
854 logical + map->stripe_len - 1,
855 &sdev->csum_list, 1);
856 if (ret)
857 goto out;
858
859 logical += increment;
860 cond_resched();
861 }
862 /*
863 * now find all extents for each stripe and scrub them
864 */
865 logical = base + offset + start_stripe * increment;
866 physical = map->stripes[num].physical + start_stripe * map->stripe_len;
867 ret = 0;
868 for (i = start_stripe; i < nstripes; ++i) {
869 /*
870 * canceled?
871 */
872 if (atomic_read(&fs_info->scrub_cancel_req) ||
873 atomic_read(&sdev->cancel_req)) {
874 ret = -ECANCELED;
875 goto out;
876 }
877 /*
878 * check to see if we have to pause
879 */
880 if (atomic_read(&fs_info->scrub_pause_req)) {
881 /* push queued extents */
882 scrub_submit(sdev);
883 wait_event(sdev->list_wait,
884 atomic_read(&sdev->in_flight) == 0);
885 atomic_inc(&fs_info->scrubs_paused);
886 wake_up(&fs_info->scrub_pause_wait);
887 mutex_lock(&fs_info->scrub_lock);
888 while (atomic_read(&fs_info->scrub_pause_req)) {
889 mutex_unlock(&fs_info->scrub_lock);
890 wait_event(fs_info->scrub_pause_wait,
891 atomic_read(&fs_info->scrub_pause_req) == 0);
892 mutex_lock(&fs_info->scrub_lock);
893 }
894 atomic_dec(&fs_info->scrubs_paused);
895 mutex_unlock(&fs_info->scrub_lock);
896 wake_up(&fs_info->scrub_pause_wait);
897 scrub_free_csums(sdev);
898 start_stripe = i;
899 goto again;
900 }
901
902 key.objectid = logical;
903 key.type = BTRFS_EXTENT_ITEM_KEY;
904 key.offset = (u64)0;
905
906 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
907 if (ret < 0)
908 goto out;
909
910 l = path->nodes[0];
911 slot = path->slots[0];
912 btrfs_item_key_to_cpu(l, &key, slot);
913 if (key.objectid != logical) {
914 ret = btrfs_previous_item(root, path, 0,
915 BTRFS_EXTENT_ITEM_KEY);
916 if (ret < 0)
917 goto out;
918 }
919
920 while (1) {
921 l = path->nodes[0];
922 slot = path->slots[0];
923 if (slot >= btrfs_header_nritems(l)) {
924 ret = btrfs_next_leaf(root, path);
925 if (ret == 0)
926 continue;
927 if (ret < 0)
928 goto out;
929
930 break;
931 }
932 btrfs_item_key_to_cpu(l, &key, slot);
933
934 if (key.objectid + key.offset <= logical)
935 goto next;
936
937 if (key.objectid >= logical + map->stripe_len)
938 break;
939
940 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY)
941 goto next;
942
943 extent = btrfs_item_ptr(l, slot,
944 struct btrfs_extent_item);
945 flags = btrfs_extent_flags(l, extent);
946 generation = btrfs_extent_generation(l, extent);
947
948 if (key.objectid < logical &&
949 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) {
950 printk(KERN_ERR
951 "btrfs scrub: tree block %llu spanning "
952 "stripes, ignored. logical=%llu\n",
953 (unsigned long long)key.objectid,
954 (unsigned long long)logical);
955 goto next;
956 }
957
958 /*
959 * trim extent to this stripe
960 */
961 if (key.objectid < logical) {
962 key.offset -= logical - key.objectid;
963 key.objectid = logical;
964 }
965 if (key.objectid + key.offset >
966 logical + map->stripe_len) {
967 key.offset = logical + map->stripe_len -
968 key.objectid;
969 }
970
971 ret = scrub_extent(sdev, key.objectid, key.offset,
972 key.objectid - logical + physical,
973 flags, generation, mirror_num);
974 if (ret)
975 goto out;
976
977 next:
978 path->slots[0]++;
979 }
980 btrfs_release_path(path);
981 logical += increment;
982 physical += map->stripe_len;
983 spin_lock(&sdev->stat_lock);
984 sdev->stat.last_physical = physical;
985 spin_unlock(&sdev->stat_lock);
986 }
987 /* push queued extents */
988 scrub_submit(sdev);
989
990 out:
991 blk_finish_plug(&plug);
992 btrfs_free_path(path);
993 return ret < 0 ? ret : 0;
994 }
995
996 static noinline_for_stack int scrub_chunk(struct scrub_dev *sdev,
997 u64 chunk_tree, u64 chunk_objectid, u64 chunk_offset, u64 length)
998 {
999 struct btrfs_mapping_tree *map_tree =
1000 &sdev->dev->dev_root->fs_info->mapping_tree;
1001 struct map_lookup *map;
1002 struct extent_map *em;
1003 int i;
1004 int ret = -EINVAL;
1005
1006 read_lock(&map_tree->map_tree.lock);
1007 em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
1008 read_unlock(&map_tree->map_tree.lock);
1009
1010 if (!em)
1011 return -EINVAL;
1012
1013 map = (struct map_lookup *)em->bdev;
1014 if (em->start != chunk_offset)
1015 goto out;
1016
1017 if (em->len < length)
1018 goto out;
1019
1020 for (i = 0; i < map->num_stripes; ++i) {
1021 if (map->stripes[i].dev == sdev->dev) {
1022 ret = scrub_stripe(sdev, map, i, chunk_offset, length);
1023 if (ret)
1024 goto out;
1025 }
1026 }
1027 out:
1028 free_extent_map(em);
1029
1030 return ret;
1031 }
1032
1033 static noinline_for_stack
1034 int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end)
1035 {
1036 struct btrfs_dev_extent *dev_extent = NULL;
1037 struct btrfs_path *path;
1038 struct btrfs_root *root = sdev->dev->dev_root;
1039 struct btrfs_fs_info *fs_info = root->fs_info;
1040 u64 length;
1041 u64 chunk_tree;
1042 u64 chunk_objectid;
1043 u64 chunk_offset;
1044 int ret;
1045 int slot;
1046 struct extent_buffer *l;
1047 struct btrfs_key key;
1048 struct btrfs_key found_key;
1049 struct btrfs_block_group_cache *cache;
1050
1051 path = btrfs_alloc_path();
1052 if (!path)
1053 return -ENOMEM;
1054
1055 path->reada = 2;
1056 path->search_commit_root = 1;
1057 path->skip_locking = 1;
1058
1059 key.objectid = sdev->dev->devid;
1060 key.offset = 0ull;
1061 key.type = BTRFS_DEV_EXTENT_KEY;
1062
1063
1064 while (1) {
1065 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1066 if (ret < 0)
1067 goto out;
1068 ret = 0;
1069
1070 l = path->nodes[0];
1071 slot = path->slots[0];
1072
1073 btrfs_item_key_to_cpu(l, &found_key, slot);
1074
1075 if (found_key.objectid != sdev->dev->devid)
1076 break;
1077
1078 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
1079 break;
1080
1081 if (found_key.offset >= end)
1082 break;
1083
1084 if (found_key.offset < key.offset)
1085 break;
1086
1087 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1088 length = btrfs_dev_extent_length(l, dev_extent);
1089
1090 if (found_key.offset + length <= start) {
1091 key.offset = found_key.offset + length;
1092 btrfs_release_path(path);
1093 continue;
1094 }
1095
1096 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
1097 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
1098 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
1099
1100 /*
1101 * get a reference on the corresponding block group to prevent
1102 * the chunk from going away while we scrub it
1103 */
1104 cache = btrfs_lookup_block_group(fs_info, chunk_offset);
1105 if (!cache) {
1106 ret = -ENOENT;
1107 goto out;
1108 }
1109 ret = scrub_chunk(sdev, chunk_tree, chunk_objectid,
1110 chunk_offset, length);
1111 btrfs_put_block_group(cache);
1112 if (ret)
1113 break;
1114
1115 key.offset = found_key.offset + length;
1116 btrfs_release_path(path);
1117 }
1118
1119 out:
1120 btrfs_free_path(path);
1121 return ret;
1122 }
1123
1124 static noinline_for_stack int scrub_supers(struct scrub_dev *sdev)
1125 {
1126 int i;
1127 u64 bytenr;
1128 u64 gen;
1129 int ret;
1130 struct btrfs_device *device = sdev->dev;
1131 struct btrfs_root *root = device->dev_root;
1132
1133 gen = root->fs_info->last_trans_committed;
1134
1135 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
1136 bytenr = btrfs_sb_offset(i);
1137 if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
1138 break;
1139
1140 ret = scrub_page(sdev, bytenr, PAGE_SIZE, bytenr,
1141 BTRFS_EXTENT_FLAG_SUPER, gen, i, NULL, 1);
1142 if (ret)
1143 return ret;
1144 }
1145 wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
1146
1147 return 0;
1148 }
1149
1150 /*
1151 * get a reference count on fs_info->scrub_workers. start worker if necessary
1152 */
1153 static noinline_for_stack int scrub_workers_get(struct btrfs_root *root)
1154 {
1155 struct btrfs_fs_info *fs_info = root->fs_info;
1156
1157 mutex_lock(&fs_info->scrub_lock);
1158 if (fs_info->scrub_workers_refcnt == 0)
1159 btrfs_start_workers(&fs_info->scrub_workers, 1);
1160 ++fs_info->scrub_workers_refcnt;
1161 mutex_unlock(&fs_info->scrub_lock);
1162
1163 return 0;
1164 }
1165
1166 static noinline_for_stack void scrub_workers_put(struct btrfs_root *root)
1167 {
1168 struct btrfs_fs_info *fs_info = root->fs_info;
1169
1170 mutex_lock(&fs_info->scrub_lock);
1171 if (--fs_info->scrub_workers_refcnt == 0)
1172 btrfs_stop_workers(&fs_info->scrub_workers);
1173 WARN_ON(fs_info->scrub_workers_refcnt < 0);
1174 mutex_unlock(&fs_info->scrub_lock);
1175 }
1176
1177
1178 int btrfs_scrub_dev(struct btrfs_root *root, u64 devid, u64 start, u64 end,
1179 struct btrfs_scrub_progress *progress, int readonly)
1180 {
1181 struct scrub_dev *sdev;
1182 struct btrfs_fs_info *fs_info = root->fs_info;
1183 int ret;
1184 struct btrfs_device *dev;
1185
1186 if (btrfs_fs_closing(root->fs_info))
1187 return -EINVAL;
1188
1189 /*
1190 * check some assumptions
1191 */
1192 if (root->sectorsize != PAGE_SIZE ||
1193 root->sectorsize != root->leafsize ||
1194 root->sectorsize != root->nodesize) {
1195 printk(KERN_ERR "btrfs_scrub: size assumptions fail\n");
1196 return -EINVAL;
1197 }
1198
1199 ret = scrub_workers_get(root);
1200 if (ret)
1201 return ret;
1202
1203 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1204 dev = btrfs_find_device(root, devid, NULL, NULL);
1205 if (!dev || dev->missing) {
1206 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1207 scrub_workers_put(root);
1208 return -ENODEV;
1209 }
1210 mutex_lock(&fs_info->scrub_lock);
1211
1212 if (!dev->in_fs_metadata) {
1213 mutex_unlock(&fs_info->scrub_lock);
1214 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1215 scrub_workers_put(root);
1216 return -ENODEV;
1217 }
1218
1219 if (dev->scrub_device) {
1220 mutex_unlock(&fs_info->scrub_lock);
1221 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1222 scrub_workers_put(root);
1223 return -EINPROGRESS;
1224 }
1225 sdev = scrub_setup_dev(dev);
1226 if (IS_ERR(sdev)) {
1227 mutex_unlock(&fs_info->scrub_lock);
1228 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1229 scrub_workers_put(root);
1230 return PTR_ERR(sdev);
1231 }
1232 sdev->readonly = readonly;
1233 dev->scrub_device = sdev;
1234
1235 atomic_inc(&fs_info->scrubs_running);
1236 mutex_unlock(&fs_info->scrub_lock);
1237 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1238
1239 down_read(&fs_info->scrub_super_lock);
1240 ret = scrub_supers(sdev);
1241 up_read(&fs_info->scrub_super_lock);
1242
1243 if (!ret)
1244 ret = scrub_enumerate_chunks(sdev, start, end);
1245
1246 wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
1247
1248 atomic_dec(&fs_info->scrubs_running);
1249 wake_up(&fs_info->scrub_pause_wait);
1250
1251 if (progress)
1252 memcpy(progress, &sdev->stat, sizeof(*progress));
1253
1254 mutex_lock(&fs_info->scrub_lock);
1255 dev->scrub_device = NULL;
1256 mutex_unlock(&fs_info->scrub_lock);
1257
1258 scrub_free_dev(sdev);
1259 scrub_workers_put(root);
1260
1261 return ret;
1262 }
1263
1264 int btrfs_scrub_pause(struct btrfs_root *root)
1265 {
1266 struct btrfs_fs_info *fs_info = root->fs_info;
1267
1268 mutex_lock(&fs_info->scrub_lock);
1269 atomic_inc(&fs_info->scrub_pause_req);
1270 while (atomic_read(&fs_info->scrubs_paused) !=
1271 atomic_read(&fs_info->scrubs_running)) {
1272 mutex_unlock(&fs_info->scrub_lock);
1273 wait_event(fs_info->scrub_pause_wait,
1274 atomic_read(&fs_info->scrubs_paused) ==
1275 atomic_read(&fs_info->scrubs_running));
1276 mutex_lock(&fs_info->scrub_lock);
1277 }
1278 mutex_unlock(&fs_info->scrub_lock);
1279
1280 return 0;
1281 }
1282
1283 int btrfs_scrub_continue(struct btrfs_root *root)
1284 {
1285 struct btrfs_fs_info *fs_info = root->fs_info;
1286
1287 atomic_dec(&fs_info->scrub_pause_req);
1288 wake_up(&fs_info->scrub_pause_wait);
1289 return 0;
1290 }
1291
1292 int btrfs_scrub_pause_super(struct btrfs_root *root)
1293 {
1294 down_write(&root->fs_info->scrub_super_lock);
1295 return 0;
1296 }
1297
1298 int btrfs_scrub_continue_super(struct btrfs_root *root)
1299 {
1300 up_write(&root->fs_info->scrub_super_lock);
1301 return 0;
1302 }
1303
1304 int btrfs_scrub_cancel(struct btrfs_root *root)
1305 {
1306 struct btrfs_fs_info *fs_info = root->fs_info;
1307
1308 mutex_lock(&fs_info->scrub_lock);
1309 if (!atomic_read(&fs_info->scrubs_running)) {
1310 mutex_unlock(&fs_info->scrub_lock);
1311 return -ENOTCONN;
1312 }
1313
1314 atomic_inc(&fs_info->scrub_cancel_req);
1315 while (atomic_read(&fs_info->scrubs_running)) {
1316 mutex_unlock(&fs_info->scrub_lock);
1317 wait_event(fs_info->scrub_pause_wait,
1318 atomic_read(&fs_info->scrubs_running) == 0);
1319 mutex_lock(&fs_info->scrub_lock);
1320 }
1321 atomic_dec(&fs_info->scrub_cancel_req);
1322 mutex_unlock(&fs_info->scrub_lock);
1323
1324 return 0;
1325 }
1326
1327 int btrfs_scrub_cancel_dev(struct btrfs_root *root, struct btrfs_device *dev)
1328 {
1329 struct btrfs_fs_info *fs_info = root->fs_info;
1330 struct scrub_dev *sdev;
1331
1332 mutex_lock(&fs_info->scrub_lock);
1333 sdev = dev->scrub_device;
1334 if (!sdev) {
1335 mutex_unlock(&fs_info->scrub_lock);
1336 return -ENOTCONN;
1337 }
1338 atomic_inc(&sdev->cancel_req);
1339 while (dev->scrub_device) {
1340 mutex_unlock(&fs_info->scrub_lock);
1341 wait_event(fs_info->scrub_pause_wait,
1342 dev->scrub_device == NULL);
1343 mutex_lock(&fs_info->scrub_lock);
1344 }
1345 mutex_unlock(&fs_info->scrub_lock);
1346
1347 return 0;
1348 }
1349 int btrfs_scrub_cancel_devid(struct btrfs_root *root, u64 devid)
1350 {
1351 struct btrfs_fs_info *fs_info = root->fs_info;
1352 struct btrfs_device *dev;
1353 int ret;
1354
1355 /*
1356 * we have to hold the device_list_mutex here so the device
1357 * does not go away in cancel_dev. FIXME: find a better solution
1358 */
1359 mutex_lock(&fs_info->fs_devices->device_list_mutex);
1360 dev = btrfs_find_device(root, devid, NULL, NULL);
1361 if (!dev) {
1362 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1363 return -ENODEV;
1364 }
1365 ret = btrfs_scrub_cancel_dev(root, dev);
1366 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1367
1368 return ret;
1369 }
1370
1371 int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
1372 struct btrfs_scrub_progress *progress)
1373 {
1374 struct btrfs_device *dev;
1375 struct scrub_dev *sdev = NULL;
1376
1377 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1378 dev = btrfs_find_device(root, devid, NULL, NULL);
1379 if (dev)
1380 sdev = dev->scrub_device;
1381 if (sdev)
1382 memcpy(progress, &sdev->stat, sizeof(*progress));
1383 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1384
1385 return dev ? (sdev ? 0 : -ENOTCONN) : -ENODEV;
1386 }
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