Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wirel...
[pandora-kernel.git] / fs / btrfs / scrub.c
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 }