btrfs: Fix up 32/64-bit compatibility for new ioctls
[linux-3.10.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 <linux/ratelimit.h>
21 #include "ctree.h"
22 #include "volumes.h"
23 #include "disk-io.h"
24 #include "ordered-data.h"
25 #include "transaction.h"
26 #include "backref.h"
27 #include "extent_io.h"
28
29 /*
30  * This is only the first step towards a full-features scrub. It reads all
31  * extent and super block and verifies the checksums. In case a bad checksum
32  * is found or the extent cannot be read, good data will be written back if
33  * any can be found.
34  *
35  * Future enhancements:
36  *  - In case an unrepairable extent is encountered, track which files are
37  *    affected and report them
38  *  - In case of a read error on files with nodatasum, map the file and read
39  *    the extent to trigger a writeback of the good copy
40  *  - track and record media errors, throw out bad devices
41  *  - add a mode to also read unallocated space
42  */
43
44 struct scrub_bio;
45 struct scrub_page;
46 struct scrub_dev;
47 static void scrub_bio_end_io(struct bio *bio, int err);
48 static void scrub_checksum(struct btrfs_work *work);
49 static int scrub_checksum_data(struct scrub_dev *sdev,
50                                struct scrub_page *spag, void *buffer);
51 static int scrub_checksum_tree_block(struct scrub_dev *sdev,
52                                      struct scrub_page *spag, u64 logical,
53                                      void *buffer);
54 static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer);
55 static int scrub_fixup_check(struct scrub_bio *sbio, int ix);
56 static void scrub_fixup_end_io(struct bio *bio, int err);
57 static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector,
58                           struct page *page);
59 static void scrub_fixup(struct scrub_bio *sbio, int ix);
60
61 #define SCRUB_PAGES_PER_BIO     16      /* 64k per bio */
62 #define SCRUB_BIOS_PER_DEV      16      /* 1 MB per device in flight */
63
64 struct scrub_page {
65         u64                     flags;  /* extent flags */
66         u64                     generation;
67         int                     mirror_num;
68         int                     have_csum;
69         u8                      csum[BTRFS_CSUM_SIZE];
70 };
71
72 struct scrub_bio {
73         int                     index;
74         struct scrub_dev        *sdev;
75         struct bio              *bio;
76         int                     err;
77         u64                     logical;
78         u64                     physical;
79         struct scrub_page       spag[SCRUB_PAGES_PER_BIO];
80         u64                     count;
81         int                     next_free;
82         struct btrfs_work       work;
83 };
84
85 struct scrub_dev {
86         struct scrub_bio        *bios[SCRUB_BIOS_PER_DEV];
87         struct btrfs_device     *dev;
88         int                     first_free;
89         int                     curr;
90         atomic_t                in_flight;
91         atomic_t                fixup_cnt;
92         spinlock_t              list_lock;
93         wait_queue_head_t       list_wait;
94         u16                     csum_size;
95         struct list_head        csum_list;
96         atomic_t                cancel_req;
97         int                     readonly;
98         /*
99          * statistics
100          */
101         struct btrfs_scrub_progress stat;
102         spinlock_t              stat_lock;
103 };
104
105 struct scrub_fixup_nodatasum {
106         struct scrub_dev        *sdev;
107         u64                     logical;
108         struct btrfs_root       *root;
109         struct btrfs_work       work;
110         int                     mirror_num;
111 };
112
113 struct scrub_warning {
114         struct btrfs_path       *path;
115         u64                     extent_item_size;
116         char                    *scratch_buf;
117         char                    *msg_buf;
118         const char              *errstr;
119         sector_t                sector;
120         u64                     logical;
121         struct btrfs_device     *dev;
122         int                     msg_bufsize;
123         int                     scratch_bufsize;
124 };
125
126 static void scrub_free_csums(struct scrub_dev *sdev)
127 {
128         while (!list_empty(&sdev->csum_list)) {
129                 struct btrfs_ordered_sum *sum;
130                 sum = list_first_entry(&sdev->csum_list,
131                                        struct btrfs_ordered_sum, list);
132                 list_del(&sum->list);
133                 kfree(sum);
134         }
135 }
136
137 static void scrub_free_bio(struct bio *bio)
138 {
139         int i;
140         struct page *last_page = NULL;
141
142         if (!bio)
143                 return;
144
145         for (i = 0; i < bio->bi_vcnt; ++i) {
146                 if (bio->bi_io_vec[i].bv_page == last_page)
147                         continue;
148                 last_page = bio->bi_io_vec[i].bv_page;
149                 __free_page(last_page);
150         }
151         bio_put(bio);
152 }
153
154 static noinline_for_stack void scrub_free_dev(struct scrub_dev *sdev)
155 {
156         int i;
157
158         if (!sdev)
159                 return;
160
161         for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
162                 struct scrub_bio *sbio = sdev->bios[i];
163
164                 if (!sbio)
165                         break;
166
167                 scrub_free_bio(sbio->bio);
168                 kfree(sbio);
169         }
170
171         scrub_free_csums(sdev);
172         kfree(sdev);
173 }
174
175 static noinline_for_stack
176 struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev)
177 {
178         struct scrub_dev *sdev;
179         int             i;
180         struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
181
182         sdev = kzalloc(sizeof(*sdev), GFP_NOFS);
183         if (!sdev)
184                 goto nomem;
185         sdev->dev = dev;
186         for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
187                 struct scrub_bio *sbio;
188
189                 sbio = kzalloc(sizeof(*sbio), GFP_NOFS);
190                 if (!sbio)
191                         goto nomem;
192                 sdev->bios[i] = sbio;
193
194                 sbio->index = i;
195                 sbio->sdev = sdev;
196                 sbio->count = 0;
197                 sbio->work.func = scrub_checksum;
198
199                 if (i != SCRUB_BIOS_PER_DEV-1)
200                         sdev->bios[i]->next_free = i + 1;
201                 else
202                         sdev->bios[i]->next_free = -1;
203         }
204         sdev->first_free = 0;
205         sdev->curr = -1;
206         atomic_set(&sdev->in_flight, 0);
207         atomic_set(&sdev->fixup_cnt, 0);
208         atomic_set(&sdev->cancel_req, 0);
209         sdev->csum_size = btrfs_super_csum_size(fs_info->super_copy);
210         INIT_LIST_HEAD(&sdev->csum_list);
211
212         spin_lock_init(&sdev->list_lock);
213         spin_lock_init(&sdev->stat_lock);
214         init_waitqueue_head(&sdev->list_wait);
215         return sdev;
216
217 nomem:
218         scrub_free_dev(sdev);
219         return ERR_PTR(-ENOMEM);
220 }
221
222 static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root, void *ctx)
223 {
224         u64 isize;
225         u32 nlink;
226         int ret;
227         int i;
228         struct extent_buffer *eb;
229         struct btrfs_inode_item *inode_item;
230         struct scrub_warning *swarn = ctx;
231         struct btrfs_fs_info *fs_info = swarn->dev->dev_root->fs_info;
232         struct inode_fs_paths *ipath = NULL;
233         struct btrfs_root *local_root;
234         struct btrfs_key root_key;
235
236         root_key.objectid = root;
237         root_key.type = BTRFS_ROOT_ITEM_KEY;
238         root_key.offset = (u64)-1;
239         local_root = btrfs_read_fs_root_no_name(fs_info, &root_key);
240         if (IS_ERR(local_root)) {
241                 ret = PTR_ERR(local_root);
242                 goto err;
243         }
244
245         ret = inode_item_info(inum, 0, local_root, swarn->path);
246         if (ret) {
247                 btrfs_release_path(swarn->path);
248                 goto err;
249         }
250
251         eb = swarn->path->nodes[0];
252         inode_item = btrfs_item_ptr(eb, swarn->path->slots[0],
253                                         struct btrfs_inode_item);
254         isize = btrfs_inode_size(eb, inode_item);
255         nlink = btrfs_inode_nlink(eb, inode_item);
256         btrfs_release_path(swarn->path);
257
258         ipath = init_ipath(4096, local_root, swarn->path);
259         ret = paths_from_inode(inum, ipath);
260
261         if (ret < 0)
262                 goto err;
263
264         /*
265          * we deliberately ignore the bit ipath might have been too small to
266          * hold all of the paths here
267          */
268         for (i = 0; i < ipath->fspath->elem_cnt; ++i)
269                 printk(KERN_WARNING "btrfs: %s at logical %llu on dev "
270                         "%s, sector %llu, root %llu, inode %llu, offset %llu, "
271                         "length %llu, links %u (path: %s)\n", swarn->errstr,
272                         swarn->logical, swarn->dev->name,
273                         (unsigned long long)swarn->sector, root, inum, offset,
274                         min(isize - offset, (u64)PAGE_SIZE), nlink,
275                         (char *)(unsigned long)ipath->fspath->val[i]);
276
277         free_ipath(ipath);
278         return 0;
279
280 err:
281         printk(KERN_WARNING "btrfs: %s at logical %llu on dev "
282                 "%s, sector %llu, root %llu, inode %llu, offset %llu: path "
283                 "resolving failed with ret=%d\n", swarn->errstr,
284                 swarn->logical, swarn->dev->name,
285                 (unsigned long long)swarn->sector, root, inum, offset, ret);
286
287         free_ipath(ipath);
288         return 0;
289 }
290
291 static void scrub_print_warning(const char *errstr, struct scrub_bio *sbio,
292                                 int ix)
293 {
294         struct btrfs_device *dev = sbio->sdev->dev;
295         struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
296         struct btrfs_path *path;
297         struct btrfs_key found_key;
298         struct extent_buffer *eb;
299         struct btrfs_extent_item *ei;
300         struct scrub_warning swarn;
301         u32 item_size;
302         int ret;
303         u64 ref_root;
304         u8 ref_level;
305         unsigned long ptr = 0;
306         const int bufsize = 4096;
307         u64 extent_offset;
308
309         path = btrfs_alloc_path();
310
311         swarn.scratch_buf = kmalloc(bufsize, GFP_NOFS);
312         swarn.msg_buf = kmalloc(bufsize, GFP_NOFS);
313         swarn.sector = (sbio->physical + ix * PAGE_SIZE) >> 9;
314         swarn.logical = sbio->logical + ix * PAGE_SIZE;
315         swarn.errstr = errstr;
316         swarn.dev = dev;
317         swarn.msg_bufsize = bufsize;
318         swarn.scratch_bufsize = bufsize;
319
320         if (!path || !swarn.scratch_buf || !swarn.msg_buf)
321                 goto out;
322
323         ret = extent_from_logical(fs_info, swarn.logical, path, &found_key);
324         if (ret < 0)
325                 goto out;
326
327         extent_offset = swarn.logical - found_key.objectid;
328         swarn.extent_item_size = found_key.offset;
329
330         eb = path->nodes[0];
331         ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
332         item_size = btrfs_item_size_nr(eb, path->slots[0]);
333
334         if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
335                 do {
336                         ret = tree_backref_for_extent(&ptr, eb, ei, item_size,
337                                                         &ref_root, &ref_level);
338                         printk(KERN_WARNING "%s at logical %llu on dev %s, "
339                                 "sector %llu: metadata %s (level %d) in tree "
340                                 "%llu\n", errstr, swarn.logical, dev->name,
341                                 (unsigned long long)swarn.sector,
342                                 ref_level ? "node" : "leaf",
343                                 ret < 0 ? -1 : ref_level,
344                                 ret < 0 ? -1 : ref_root);
345                 } while (ret != 1);
346         } else {
347                 swarn.path = path;
348                 iterate_extent_inodes(fs_info, path, found_key.objectid,
349                                         extent_offset,
350                                         scrub_print_warning_inode, &swarn);
351         }
352
353 out:
354         btrfs_free_path(path);
355         kfree(swarn.scratch_buf);
356         kfree(swarn.msg_buf);
357 }
358
359 static int scrub_fixup_readpage(u64 inum, u64 offset, u64 root, void *ctx)
360 {
361         struct page *page = NULL;
362         unsigned long index;
363         struct scrub_fixup_nodatasum *fixup = ctx;
364         int ret;
365         int corrected = 0;
366         struct btrfs_key key;
367         struct inode *inode = NULL;
368         u64 end = offset + PAGE_SIZE - 1;
369         struct btrfs_root *local_root;
370
371         key.objectid = root;
372         key.type = BTRFS_ROOT_ITEM_KEY;
373         key.offset = (u64)-1;
374         local_root = btrfs_read_fs_root_no_name(fixup->root->fs_info, &key);
375         if (IS_ERR(local_root))
376                 return PTR_ERR(local_root);
377
378         key.type = BTRFS_INODE_ITEM_KEY;
379         key.objectid = inum;
380         key.offset = 0;
381         inode = btrfs_iget(fixup->root->fs_info->sb, &key, local_root, NULL);
382         if (IS_ERR(inode))
383                 return PTR_ERR(inode);
384
385         index = offset >> PAGE_CACHE_SHIFT;
386
387         page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
388         if (!page) {
389                 ret = -ENOMEM;
390                 goto out;
391         }
392
393         if (PageUptodate(page)) {
394                 struct btrfs_mapping_tree *map_tree;
395                 if (PageDirty(page)) {
396                         /*
397                          * we need to write the data to the defect sector. the
398                          * data that was in that sector is not in memory,
399                          * because the page was modified. we must not write the
400                          * modified page to that sector.
401                          *
402                          * TODO: what could be done here: wait for the delalloc
403                          *       runner to write out that page (might involve
404                          *       COW) and see whether the sector is still
405                          *       referenced afterwards.
406                          *
407                          * For the meantime, we'll treat this error
408                          * incorrectable, although there is a chance that a
409                          * later scrub will find the bad sector again and that
410                          * there's no dirty page in memory, then.
411                          */
412                         ret = -EIO;
413                         goto out;
414                 }
415                 map_tree = &BTRFS_I(inode)->root->fs_info->mapping_tree;
416                 ret = repair_io_failure(map_tree, offset, PAGE_SIZE,
417                                         fixup->logical, page,
418                                         fixup->mirror_num);
419                 unlock_page(page);
420                 corrected = !ret;
421         } else {
422                 /*
423                  * we need to get good data first. the general readpage path
424                  * will call repair_io_failure for us, we just have to make
425                  * sure we read the bad mirror.
426                  */
427                 ret = set_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
428                                         EXTENT_DAMAGED, GFP_NOFS);
429                 if (ret) {
430                         /* set_extent_bits should give proper error */
431                         WARN_ON(ret > 0);
432                         if (ret > 0)
433                                 ret = -EFAULT;
434                         goto out;
435                 }
436
437                 ret = extent_read_full_page(&BTRFS_I(inode)->io_tree, page,
438                                                 btrfs_get_extent,
439                                                 fixup->mirror_num);
440                 wait_on_page_locked(page);
441
442                 corrected = !test_range_bit(&BTRFS_I(inode)->io_tree, offset,
443                                                 end, EXTENT_DAMAGED, 0, NULL);
444                 if (!corrected)
445                         clear_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
446                                                 EXTENT_DAMAGED, GFP_NOFS);
447         }
448
449 out:
450         if (page)
451                 put_page(page);
452         if (inode)
453                 iput(inode);
454
455         if (ret < 0)
456                 return ret;
457
458         if (ret == 0 && corrected) {
459                 /*
460                  * we only need to call readpage for one of the inodes belonging
461                  * to this extent. so make iterate_extent_inodes stop
462                  */
463                 return 1;
464         }
465
466         return -EIO;
467 }
468
469 static void scrub_fixup_nodatasum(struct btrfs_work *work)
470 {
471         int ret;
472         struct scrub_fixup_nodatasum *fixup;
473         struct scrub_dev *sdev;
474         struct btrfs_trans_handle *trans = NULL;
475         struct btrfs_fs_info *fs_info;
476         struct btrfs_path *path;
477         int uncorrectable = 0;
478
479         fixup = container_of(work, struct scrub_fixup_nodatasum, work);
480         sdev = fixup->sdev;
481         fs_info = fixup->root->fs_info;
482
483         path = btrfs_alloc_path();
484         if (!path) {
485                 spin_lock(&sdev->stat_lock);
486                 ++sdev->stat.malloc_errors;
487                 spin_unlock(&sdev->stat_lock);
488                 uncorrectable = 1;
489                 goto out;
490         }
491
492         trans = btrfs_join_transaction(fixup->root);
493         if (IS_ERR(trans)) {
494                 uncorrectable = 1;
495                 goto out;
496         }
497
498         /*
499          * the idea is to trigger a regular read through the standard path. we
500          * read a page from the (failed) logical address by specifying the
501          * corresponding copynum of the failed sector. thus, that readpage is
502          * expected to fail.
503          * that is the point where on-the-fly error correction will kick in
504          * (once it's finished) and rewrite the failed sector if a good copy
505          * can be found.
506          */
507         ret = iterate_inodes_from_logical(fixup->logical, fixup->root->fs_info,
508                                                 path, scrub_fixup_readpage,
509                                                 fixup);
510         if (ret < 0) {
511                 uncorrectable = 1;
512                 goto out;
513         }
514         WARN_ON(ret != 1);
515
516         spin_lock(&sdev->stat_lock);
517         ++sdev->stat.corrected_errors;
518         spin_unlock(&sdev->stat_lock);
519
520 out:
521         if (trans && !IS_ERR(trans))
522                 btrfs_end_transaction(trans, fixup->root);
523         if (uncorrectable) {
524                 spin_lock(&sdev->stat_lock);
525                 ++sdev->stat.uncorrectable_errors;
526                 spin_unlock(&sdev->stat_lock);
527                 printk_ratelimited(KERN_ERR "btrfs: unable to fixup "
528                                         "(nodatasum) error at logical %llu\n",
529                                         fixup->logical);
530         }
531
532         btrfs_free_path(path);
533         kfree(fixup);
534
535         /* see caller why we're pretending to be paused in the scrub counters */
536         mutex_lock(&fs_info->scrub_lock);
537         atomic_dec(&fs_info->scrubs_running);
538         atomic_dec(&fs_info->scrubs_paused);
539         mutex_unlock(&fs_info->scrub_lock);
540         atomic_dec(&sdev->fixup_cnt);
541         wake_up(&fs_info->scrub_pause_wait);
542         wake_up(&sdev->list_wait);
543 }
544
545 /*
546  * scrub_recheck_error gets called when either verification of the page
547  * failed or the bio failed to read, e.g. with EIO. In the latter case,
548  * recheck_error gets called for every page in the bio, even though only
549  * one may be bad
550  */
551 static int scrub_recheck_error(struct scrub_bio *sbio, int ix)
552 {
553         struct scrub_dev *sdev = sbio->sdev;
554         u64 sector = (sbio->physical + ix * PAGE_SIZE) >> 9;
555         static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
556                                         DEFAULT_RATELIMIT_BURST);
557
558         if (sbio->err) {
559                 if (scrub_fixup_io(READ, sbio->sdev->dev->bdev, sector,
560                                    sbio->bio->bi_io_vec[ix].bv_page) == 0) {
561                         if (scrub_fixup_check(sbio, ix) == 0)
562                                 return 0;
563                 }
564                 if (__ratelimit(&_rs))
565                         scrub_print_warning("i/o error", sbio, ix);
566         } else {
567                 if (__ratelimit(&_rs))
568                         scrub_print_warning("checksum error", sbio, ix);
569         }
570
571         spin_lock(&sdev->stat_lock);
572         ++sdev->stat.read_errors;
573         spin_unlock(&sdev->stat_lock);
574
575         scrub_fixup(sbio, ix);
576         return 1;
577 }
578
579 static int scrub_fixup_check(struct scrub_bio *sbio, int ix)
580 {
581         int ret = 1;
582         struct page *page;
583         void *buffer;
584         u64 flags = sbio->spag[ix].flags;
585
586         page = sbio->bio->bi_io_vec[ix].bv_page;
587         buffer = kmap_atomic(page, KM_USER0);
588         if (flags & BTRFS_EXTENT_FLAG_DATA) {
589                 ret = scrub_checksum_data(sbio->sdev,
590                                           sbio->spag + ix, buffer);
591         } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
592                 ret = scrub_checksum_tree_block(sbio->sdev,
593                                                 sbio->spag + ix,
594                                                 sbio->logical + ix * PAGE_SIZE,
595                                                 buffer);
596         } else {
597                 WARN_ON(1);
598         }
599         kunmap_atomic(buffer, KM_USER0);
600
601         return ret;
602 }
603
604 static void scrub_fixup_end_io(struct bio *bio, int err)
605 {
606         complete((struct completion *)bio->bi_private);
607 }
608
609 static void scrub_fixup(struct scrub_bio *sbio, int ix)
610 {
611         struct scrub_dev *sdev = sbio->sdev;
612         struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
613         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
614         struct btrfs_bio *bbio = NULL;
615         struct scrub_fixup_nodatasum *fixup;
616         u64 logical = sbio->logical + ix * PAGE_SIZE;
617         u64 length;
618         int i;
619         int ret;
620         DECLARE_COMPLETION_ONSTACK(complete);
621
622         if ((sbio->spag[ix].flags & BTRFS_EXTENT_FLAG_DATA) &&
623             (sbio->spag[ix].have_csum == 0)) {
624                 fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
625                 if (!fixup)
626                         goto uncorrectable;
627                 fixup->sdev = sdev;
628                 fixup->logical = logical;
629                 fixup->root = fs_info->extent_root;
630                 fixup->mirror_num = sbio->spag[ix].mirror_num;
631                 /*
632                  * increment scrubs_running to prevent cancel requests from
633                  * completing as long as a fixup worker is running. we must also
634                  * increment scrubs_paused to prevent deadlocking on pause
635                  * requests used for transactions commits (as the worker uses a
636                  * transaction context). it is safe to regard the fixup worker
637                  * as paused for all matters practical. effectively, we only
638                  * avoid cancellation requests from completing.
639                  */
640                 mutex_lock(&fs_info->scrub_lock);
641                 atomic_inc(&fs_info->scrubs_running);
642                 atomic_inc(&fs_info->scrubs_paused);
643                 mutex_unlock(&fs_info->scrub_lock);
644                 atomic_inc(&sdev->fixup_cnt);
645                 fixup->work.func = scrub_fixup_nodatasum;
646                 btrfs_queue_worker(&fs_info->scrub_workers, &fixup->work);
647                 return;
648         }
649
650         length = PAGE_SIZE;
651         ret = btrfs_map_block(map_tree, REQ_WRITE, logical, &length,
652                               &bbio, 0);
653         if (ret || !bbio || length < PAGE_SIZE) {
654                 printk(KERN_ERR
655                        "scrub_fixup: btrfs_map_block failed us for %llu\n",
656                        (unsigned long long)logical);
657                 WARN_ON(1);
658                 kfree(bbio);
659                 return;
660         }
661
662         if (bbio->num_stripes == 1)
663                 /* there aren't any replicas */
664                 goto uncorrectable;
665
666         /*
667          * first find a good copy
668          */
669         for (i = 0; i < bbio->num_stripes; ++i) {
670                 if (i + 1 == sbio->spag[ix].mirror_num)
671                         continue;
672
673                 if (scrub_fixup_io(READ, bbio->stripes[i].dev->bdev,
674                                    bbio->stripes[i].physical >> 9,
675                                    sbio->bio->bi_io_vec[ix].bv_page)) {
676                         /* I/O-error, this is not a good copy */
677                         continue;
678                 }
679
680                 if (scrub_fixup_check(sbio, ix) == 0)
681                         break;
682         }
683         if (i == bbio->num_stripes)
684                 goto uncorrectable;
685
686         if (!sdev->readonly) {
687                 /*
688                  * bi_io_vec[ix].bv_page now contains good data, write it back
689                  */
690                 if (scrub_fixup_io(WRITE, sdev->dev->bdev,
691                                    (sbio->physical + ix * PAGE_SIZE) >> 9,
692                                    sbio->bio->bi_io_vec[ix].bv_page)) {
693                         /* I/O-error, writeback failed, give up */
694                         goto uncorrectable;
695                 }
696         }
697
698         kfree(bbio);
699         spin_lock(&sdev->stat_lock);
700         ++sdev->stat.corrected_errors;
701         spin_unlock(&sdev->stat_lock);
702
703         printk_ratelimited(KERN_ERR "btrfs: fixed up error at logical %llu\n",
704                                (unsigned long long)logical);
705         return;
706
707 uncorrectable:
708         kfree(bbio);
709         spin_lock(&sdev->stat_lock);
710         ++sdev->stat.uncorrectable_errors;
711         spin_unlock(&sdev->stat_lock);
712
713         printk_ratelimited(KERN_ERR "btrfs: unable to fixup (regular) error at "
714                                 "logical %llu\n", (unsigned long long)logical);
715 }
716
717 static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector,
718                          struct page *page)
719 {
720         struct bio *bio = NULL;
721         int ret;
722         DECLARE_COMPLETION_ONSTACK(complete);
723
724         bio = bio_alloc(GFP_NOFS, 1);
725         bio->bi_bdev = bdev;
726         bio->bi_sector = sector;
727         bio_add_page(bio, page, PAGE_SIZE, 0);
728         bio->bi_end_io = scrub_fixup_end_io;
729         bio->bi_private = &complete;
730         submit_bio(rw, bio);
731
732         /* this will also unplug the queue */
733         wait_for_completion(&complete);
734
735         ret = !test_bit(BIO_UPTODATE, &bio->bi_flags);
736         bio_put(bio);
737         return ret;
738 }
739
740 static void scrub_bio_end_io(struct bio *bio, int err)
741 {
742         struct scrub_bio *sbio = bio->bi_private;
743         struct scrub_dev *sdev = sbio->sdev;
744         struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
745
746         sbio->err = err;
747         sbio->bio = bio;
748
749         btrfs_queue_worker(&fs_info->scrub_workers, &sbio->work);
750 }
751
752 static void scrub_checksum(struct btrfs_work *work)
753 {
754         struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
755         struct scrub_dev *sdev = sbio->sdev;
756         struct page *page;
757         void *buffer;
758         int i;
759         u64 flags;
760         u64 logical;
761         int ret;
762
763         if (sbio->err) {
764                 ret = 0;
765                 for (i = 0; i < sbio->count; ++i)
766                         ret |= scrub_recheck_error(sbio, i);
767                 if (!ret) {
768                         spin_lock(&sdev->stat_lock);
769                         ++sdev->stat.unverified_errors;
770                         spin_unlock(&sdev->stat_lock);
771                 }
772
773                 sbio->bio->bi_flags &= ~(BIO_POOL_MASK - 1);
774                 sbio->bio->bi_flags |= 1 << BIO_UPTODATE;
775                 sbio->bio->bi_phys_segments = 0;
776                 sbio->bio->bi_idx = 0;
777
778                 for (i = 0; i < sbio->count; i++) {
779                         struct bio_vec *bi;
780                         bi = &sbio->bio->bi_io_vec[i];
781                         bi->bv_offset = 0;
782                         bi->bv_len = PAGE_SIZE;
783                 }
784                 goto out;
785         }
786         for (i = 0; i < sbio->count; ++i) {
787                 page = sbio->bio->bi_io_vec[i].bv_page;
788                 buffer = kmap_atomic(page, KM_USER0);
789                 flags = sbio->spag[i].flags;
790                 logical = sbio->logical + i * PAGE_SIZE;
791                 ret = 0;
792                 if (flags & BTRFS_EXTENT_FLAG_DATA) {
793                         ret = scrub_checksum_data(sdev, sbio->spag + i, buffer);
794                 } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
795                         ret = scrub_checksum_tree_block(sdev, sbio->spag + i,
796                                                         logical, buffer);
797                 } else if (flags & BTRFS_EXTENT_FLAG_SUPER) {
798                         BUG_ON(i);
799                         (void)scrub_checksum_super(sbio, buffer);
800                 } else {
801                         WARN_ON(1);
802                 }
803                 kunmap_atomic(buffer, KM_USER0);
804                 if (ret) {
805                         ret = scrub_recheck_error(sbio, i);
806                         if (!ret) {
807                                 spin_lock(&sdev->stat_lock);
808                                 ++sdev->stat.unverified_errors;
809                                 spin_unlock(&sdev->stat_lock);
810                         }
811                 }
812         }
813
814 out:
815         scrub_free_bio(sbio->bio);
816         sbio->bio = NULL;
817         spin_lock(&sdev->list_lock);
818         sbio->next_free = sdev->first_free;
819         sdev->first_free = sbio->index;
820         spin_unlock(&sdev->list_lock);
821         atomic_dec(&sdev->in_flight);
822         wake_up(&sdev->list_wait);
823 }
824
825 static int scrub_checksum_data(struct scrub_dev *sdev,
826                                struct scrub_page *spag, void *buffer)
827 {
828         u8 csum[BTRFS_CSUM_SIZE];
829         u32 crc = ~(u32)0;
830         int fail = 0;
831         struct btrfs_root *root = sdev->dev->dev_root;
832
833         if (!spag->have_csum)
834                 return 0;
835
836         crc = btrfs_csum_data(root, buffer, crc, PAGE_SIZE);
837         btrfs_csum_final(crc, csum);
838         if (memcmp(csum, spag->csum, sdev->csum_size))
839                 fail = 1;
840
841         spin_lock(&sdev->stat_lock);
842         ++sdev->stat.data_extents_scrubbed;
843         sdev->stat.data_bytes_scrubbed += PAGE_SIZE;
844         if (fail)
845                 ++sdev->stat.csum_errors;
846         spin_unlock(&sdev->stat_lock);
847
848         return fail;
849 }
850
851 static int scrub_checksum_tree_block(struct scrub_dev *sdev,
852                                      struct scrub_page *spag, u64 logical,
853                                      void *buffer)
854 {
855         struct btrfs_header *h;
856         struct btrfs_root *root = sdev->dev->dev_root;
857         struct btrfs_fs_info *fs_info = root->fs_info;
858         u8 csum[BTRFS_CSUM_SIZE];
859         u32 crc = ~(u32)0;
860         int fail = 0;
861         int crc_fail = 0;
862
863         /*
864          * we don't use the getter functions here, as we
865          * a) don't have an extent buffer and
866          * b) the page is already kmapped
867          */
868         h = (struct btrfs_header *)buffer;
869
870         if (logical != le64_to_cpu(h->bytenr))
871                 ++fail;
872
873         if (spag->generation != le64_to_cpu(h->generation))
874                 ++fail;
875
876         if (memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
877                 ++fail;
878
879         if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
880                    BTRFS_UUID_SIZE))
881                 ++fail;
882
883         crc = btrfs_csum_data(root, buffer + BTRFS_CSUM_SIZE, crc,
884                               PAGE_SIZE - BTRFS_CSUM_SIZE);
885         btrfs_csum_final(crc, csum);
886         if (memcmp(csum, h->csum, sdev->csum_size))
887                 ++crc_fail;
888
889         spin_lock(&sdev->stat_lock);
890         ++sdev->stat.tree_extents_scrubbed;
891         sdev->stat.tree_bytes_scrubbed += PAGE_SIZE;
892         if (crc_fail)
893                 ++sdev->stat.csum_errors;
894         if (fail)
895                 ++sdev->stat.verify_errors;
896         spin_unlock(&sdev->stat_lock);
897
898         return fail || crc_fail;
899 }
900
901 static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer)
902 {
903         struct btrfs_super_block *s;
904         u64 logical;
905         struct scrub_dev *sdev = sbio->sdev;
906         struct btrfs_root *root = sdev->dev->dev_root;
907         struct btrfs_fs_info *fs_info = root->fs_info;
908         u8 csum[BTRFS_CSUM_SIZE];
909         u32 crc = ~(u32)0;
910         int fail = 0;
911
912         s = (struct btrfs_super_block *)buffer;
913         logical = sbio->logical;
914
915         if (logical != le64_to_cpu(s->bytenr))
916                 ++fail;
917
918         if (sbio->spag[0].generation != le64_to_cpu(s->generation))
919                 ++fail;
920
921         if (memcmp(s->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
922                 ++fail;
923
924         crc = btrfs_csum_data(root, buffer + BTRFS_CSUM_SIZE, crc,
925                               PAGE_SIZE - BTRFS_CSUM_SIZE);
926         btrfs_csum_final(crc, csum);
927         if (memcmp(csum, s->csum, sbio->sdev->csum_size))
928                 ++fail;
929
930         if (fail) {
931                 /*
932                  * if we find an error in a super block, we just report it.
933                  * They will get written with the next transaction commit
934                  * anyway
935                  */
936                 spin_lock(&sdev->stat_lock);
937                 ++sdev->stat.super_errors;
938                 spin_unlock(&sdev->stat_lock);
939         }
940
941         return fail;
942 }
943
944 static int scrub_submit(struct scrub_dev *sdev)
945 {
946         struct scrub_bio *sbio;
947
948         if (sdev->curr == -1)
949                 return 0;
950
951         sbio = sdev->bios[sdev->curr];
952         sbio->err = 0;
953         sdev->curr = -1;
954         atomic_inc(&sdev->in_flight);
955
956         submit_bio(READ, sbio->bio);
957
958         return 0;
959 }
960
961 static int scrub_page(struct scrub_dev *sdev, u64 logical, u64 len,
962                       u64 physical, u64 flags, u64 gen, int mirror_num,
963                       u8 *csum, int force)
964 {
965         struct scrub_bio *sbio;
966         struct page *page;
967         int ret;
968
969 again:
970         /*
971          * grab a fresh bio or wait for one to become available
972          */
973         while (sdev->curr == -1) {
974                 spin_lock(&sdev->list_lock);
975                 sdev->curr = sdev->first_free;
976                 if (sdev->curr != -1) {
977                         sdev->first_free = sdev->bios[sdev->curr]->next_free;
978                         sdev->bios[sdev->curr]->next_free = -1;
979                         sdev->bios[sdev->curr]->count = 0;
980                         spin_unlock(&sdev->list_lock);
981                 } else {
982                         spin_unlock(&sdev->list_lock);
983                         wait_event(sdev->list_wait, sdev->first_free != -1);
984                 }
985         }
986         sbio = sdev->bios[sdev->curr];
987         if (sbio->count == 0) {
988                 struct bio *bio;
989
990                 sbio->physical = physical;
991                 sbio->logical = logical;
992                 bio = bio_alloc(GFP_NOFS, SCRUB_PAGES_PER_BIO);
993                 if (!bio)
994                         return -ENOMEM;
995
996                 bio->bi_private = sbio;
997                 bio->bi_end_io = scrub_bio_end_io;
998                 bio->bi_bdev = sdev->dev->bdev;
999                 bio->bi_sector = sbio->physical >> 9;
1000                 sbio->err = 0;
1001                 sbio->bio = bio;
1002         } else if (sbio->physical + sbio->count * PAGE_SIZE != physical ||
1003                    sbio->logical + sbio->count * PAGE_SIZE != logical) {
1004                 ret = scrub_submit(sdev);
1005                 if (ret)
1006                         return ret;
1007                 goto again;
1008         }
1009         sbio->spag[sbio->count].flags = flags;
1010         sbio->spag[sbio->count].generation = gen;
1011         sbio->spag[sbio->count].have_csum = 0;
1012         sbio->spag[sbio->count].mirror_num = mirror_num;
1013
1014         page = alloc_page(GFP_NOFS);
1015         if (!page)
1016                 return -ENOMEM;
1017
1018         ret = bio_add_page(sbio->bio, page, PAGE_SIZE, 0);
1019         if (!ret) {
1020                 __free_page(page);
1021                 ret = scrub_submit(sdev);
1022                 if (ret)
1023                         return ret;
1024                 goto again;
1025         }
1026
1027         if (csum) {
1028                 sbio->spag[sbio->count].have_csum = 1;
1029                 memcpy(sbio->spag[sbio->count].csum, csum, sdev->csum_size);
1030         }
1031         ++sbio->count;
1032         if (sbio->count == SCRUB_PAGES_PER_BIO || force) {
1033                 int ret;
1034
1035                 ret = scrub_submit(sdev);
1036                 if (ret)
1037                         return ret;
1038         }
1039
1040         return 0;
1041 }
1042
1043 static int scrub_find_csum(struct scrub_dev *sdev, u64 logical, u64 len,
1044                            u8 *csum)
1045 {
1046         struct btrfs_ordered_sum *sum = NULL;
1047         int ret = 0;
1048         unsigned long i;
1049         unsigned long num_sectors;
1050         u32 sectorsize = sdev->dev->dev_root->sectorsize;
1051
1052         while (!list_empty(&sdev->csum_list)) {
1053                 sum = list_first_entry(&sdev->csum_list,
1054                                        struct btrfs_ordered_sum, list);
1055                 if (sum->bytenr > logical)
1056                         return 0;
1057                 if (sum->bytenr + sum->len > logical)
1058                         break;
1059
1060                 ++sdev->stat.csum_discards;
1061                 list_del(&sum->list);
1062                 kfree(sum);
1063                 sum = NULL;
1064         }
1065         if (!sum)
1066                 return 0;
1067
1068         num_sectors = sum->len / sectorsize;
1069         for (i = 0; i < num_sectors; ++i) {
1070                 if (sum->sums[i].bytenr == logical) {
1071                         memcpy(csum, &sum->sums[i].sum, sdev->csum_size);
1072                         ret = 1;
1073                         break;
1074                 }
1075         }
1076         if (ret && i == num_sectors - 1) {
1077                 list_del(&sum->list);
1078                 kfree(sum);
1079         }
1080         return ret;
1081 }
1082
1083 /* scrub extent tries to collect up to 64 kB for each bio */
1084 static int scrub_extent(struct scrub_dev *sdev, u64 logical, u64 len,
1085                         u64 physical, u64 flags, u64 gen, int mirror_num)
1086 {
1087         int ret;
1088         u8 csum[BTRFS_CSUM_SIZE];
1089
1090         while (len) {
1091                 u64 l = min_t(u64, len, PAGE_SIZE);
1092                 int have_csum = 0;
1093
1094                 if (flags & BTRFS_EXTENT_FLAG_DATA) {
1095                         /* push csums to sbio */
1096                         have_csum = scrub_find_csum(sdev, logical, l, csum);
1097                         if (have_csum == 0)
1098                                 ++sdev->stat.no_csum;
1099                 }
1100                 ret = scrub_page(sdev, logical, l, physical, flags, gen,
1101                                  mirror_num, have_csum ? csum : NULL, 0);
1102                 if (ret)
1103                         return ret;
1104                 len -= l;
1105                 logical += l;
1106                 physical += l;
1107         }
1108         return 0;
1109 }
1110
1111 static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev,
1112         struct map_lookup *map, int num, u64 base, u64 length)
1113 {
1114         struct btrfs_path *path;
1115         struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
1116         struct btrfs_root *root = fs_info->extent_root;
1117         struct btrfs_root *csum_root = fs_info->csum_root;
1118         struct btrfs_extent_item *extent;
1119         struct blk_plug plug;
1120         u64 flags;
1121         int ret;
1122         int slot;
1123         int i;
1124         u64 nstripes;
1125         struct extent_buffer *l;
1126         struct btrfs_key key;
1127         u64 physical;
1128         u64 logical;
1129         u64 generation;
1130         int mirror_num;
1131         struct reada_control *reada1;
1132         struct reada_control *reada2;
1133         struct btrfs_key key_start;
1134         struct btrfs_key key_end;
1135
1136         u64 increment = map->stripe_len;
1137         u64 offset;
1138
1139         nstripes = length;
1140         offset = 0;
1141         do_div(nstripes, map->stripe_len);
1142         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
1143                 offset = map->stripe_len * num;
1144                 increment = map->stripe_len * map->num_stripes;
1145                 mirror_num = 1;
1146         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1147                 int factor = map->num_stripes / map->sub_stripes;
1148                 offset = map->stripe_len * (num / map->sub_stripes);
1149                 increment = map->stripe_len * factor;
1150                 mirror_num = num % map->sub_stripes + 1;
1151         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
1152                 increment = map->stripe_len;
1153                 mirror_num = num % map->num_stripes + 1;
1154         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
1155                 increment = map->stripe_len;
1156                 mirror_num = num % map->num_stripes + 1;
1157         } else {
1158                 increment = map->stripe_len;
1159                 mirror_num = 1;
1160         }
1161
1162         path = btrfs_alloc_path();
1163         if (!path)
1164                 return -ENOMEM;
1165
1166         path->search_commit_root = 1;
1167         path->skip_locking = 1;
1168
1169         /*
1170          * trigger the readahead for extent tree csum tree and wait for
1171          * completion. During readahead, the scrub is officially paused
1172          * to not hold off transaction commits
1173          */
1174         logical = base + offset;
1175
1176         wait_event(sdev->list_wait,
1177                    atomic_read(&sdev->in_flight) == 0);
1178         atomic_inc(&fs_info->scrubs_paused);
1179         wake_up(&fs_info->scrub_pause_wait);
1180
1181         /* FIXME it might be better to start readahead at commit root */
1182         key_start.objectid = logical;
1183         key_start.type = BTRFS_EXTENT_ITEM_KEY;
1184         key_start.offset = (u64)0;
1185         key_end.objectid = base + offset + nstripes * increment;
1186         key_end.type = BTRFS_EXTENT_ITEM_KEY;
1187         key_end.offset = (u64)0;
1188         reada1 = btrfs_reada_add(root, &key_start, &key_end);
1189
1190         key_start.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
1191         key_start.type = BTRFS_EXTENT_CSUM_KEY;
1192         key_start.offset = logical;
1193         key_end.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
1194         key_end.type = BTRFS_EXTENT_CSUM_KEY;
1195         key_end.offset = base + offset + nstripes * increment;
1196         reada2 = btrfs_reada_add(csum_root, &key_start, &key_end);
1197
1198         if (!IS_ERR(reada1))
1199                 btrfs_reada_wait(reada1);
1200         if (!IS_ERR(reada2))
1201                 btrfs_reada_wait(reada2);
1202
1203         mutex_lock(&fs_info->scrub_lock);
1204         while (atomic_read(&fs_info->scrub_pause_req)) {
1205                 mutex_unlock(&fs_info->scrub_lock);
1206                 wait_event(fs_info->scrub_pause_wait,
1207                    atomic_read(&fs_info->scrub_pause_req) == 0);
1208                 mutex_lock(&fs_info->scrub_lock);
1209         }
1210         atomic_dec(&fs_info->scrubs_paused);
1211         mutex_unlock(&fs_info->scrub_lock);
1212         wake_up(&fs_info->scrub_pause_wait);
1213
1214         /*
1215          * collect all data csums for the stripe to avoid seeking during
1216          * the scrub. This might currently (crc32) end up to be about 1MB
1217          */
1218         blk_start_plug(&plug);
1219
1220         /*
1221          * now find all extents for each stripe and scrub them
1222          */
1223         logical = base + offset;
1224         physical = map->stripes[num].physical;
1225         ret = 0;
1226         for (i = 0; i < nstripes; ++i) {
1227                 /*
1228                  * canceled?
1229                  */
1230                 if (atomic_read(&fs_info->scrub_cancel_req) ||
1231                     atomic_read(&sdev->cancel_req)) {
1232                         ret = -ECANCELED;
1233                         goto out;
1234                 }
1235                 /*
1236                  * check to see if we have to pause
1237                  */
1238                 if (atomic_read(&fs_info->scrub_pause_req)) {
1239                         /* push queued extents */
1240                         scrub_submit(sdev);
1241                         wait_event(sdev->list_wait,
1242                                    atomic_read(&sdev->in_flight) == 0);
1243                         atomic_inc(&fs_info->scrubs_paused);
1244                         wake_up(&fs_info->scrub_pause_wait);
1245                         mutex_lock(&fs_info->scrub_lock);
1246                         while (atomic_read(&fs_info->scrub_pause_req)) {
1247                                 mutex_unlock(&fs_info->scrub_lock);
1248                                 wait_event(fs_info->scrub_pause_wait,
1249                                    atomic_read(&fs_info->scrub_pause_req) == 0);
1250                                 mutex_lock(&fs_info->scrub_lock);
1251                         }
1252                         atomic_dec(&fs_info->scrubs_paused);
1253                         mutex_unlock(&fs_info->scrub_lock);
1254                         wake_up(&fs_info->scrub_pause_wait);
1255                 }
1256
1257                 ret = btrfs_lookup_csums_range(csum_root, logical,
1258                                                logical + map->stripe_len - 1,
1259                                                &sdev->csum_list, 1);
1260                 if (ret)
1261                         goto out;
1262
1263                 key.objectid = logical;
1264                 key.type = BTRFS_EXTENT_ITEM_KEY;
1265                 key.offset = (u64)0;
1266
1267                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1268                 if (ret < 0)
1269                         goto out;
1270                 if (ret > 0) {
1271                         ret = btrfs_previous_item(root, path, 0,
1272                                                   BTRFS_EXTENT_ITEM_KEY);
1273                         if (ret < 0)
1274                                 goto out;
1275                         if (ret > 0) {
1276                                 /* there's no smaller item, so stick with the
1277                                  * larger one */
1278                                 btrfs_release_path(path);
1279                                 ret = btrfs_search_slot(NULL, root, &key,
1280                                                         path, 0, 0);
1281                                 if (ret < 0)
1282                                         goto out;
1283                         }
1284                 }
1285
1286                 while (1) {
1287                         l = path->nodes[0];
1288                         slot = path->slots[0];
1289                         if (slot >= btrfs_header_nritems(l)) {
1290                                 ret = btrfs_next_leaf(root, path);
1291                                 if (ret == 0)
1292                                         continue;
1293                                 if (ret < 0)
1294                                         goto out;
1295
1296                                 break;
1297                         }
1298                         btrfs_item_key_to_cpu(l, &key, slot);
1299
1300                         if (key.objectid + key.offset <= logical)
1301                                 goto next;
1302
1303                         if (key.objectid >= logical + map->stripe_len)
1304                                 break;
1305
1306                         if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY)
1307                                 goto next;
1308
1309                         extent = btrfs_item_ptr(l, slot,
1310                                                 struct btrfs_extent_item);
1311                         flags = btrfs_extent_flags(l, extent);
1312                         generation = btrfs_extent_generation(l, extent);
1313
1314                         if (key.objectid < logical &&
1315                             (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) {
1316                                 printk(KERN_ERR
1317                                        "btrfs scrub: tree block %llu spanning "
1318                                        "stripes, ignored. logical=%llu\n",
1319                                        (unsigned long long)key.objectid,
1320                                        (unsigned long long)logical);
1321                                 goto next;
1322                         }
1323
1324                         /*
1325                          * trim extent to this stripe
1326                          */
1327                         if (key.objectid < logical) {
1328                                 key.offset -= logical - key.objectid;
1329                                 key.objectid = logical;
1330                         }
1331                         if (key.objectid + key.offset >
1332                             logical + map->stripe_len) {
1333                                 key.offset = logical + map->stripe_len -
1334                                              key.objectid;
1335                         }
1336
1337                         ret = scrub_extent(sdev, key.objectid, key.offset,
1338                                            key.objectid - logical + physical,
1339                                            flags, generation, mirror_num);
1340                         if (ret)
1341                                 goto out;
1342
1343 next:
1344                         path->slots[0]++;
1345                 }
1346                 btrfs_release_path(path);
1347                 logical += increment;
1348                 physical += map->stripe_len;
1349                 spin_lock(&sdev->stat_lock);
1350                 sdev->stat.last_physical = physical;
1351                 spin_unlock(&sdev->stat_lock);
1352         }
1353         /* push queued extents */
1354         scrub_submit(sdev);
1355
1356 out:
1357         blk_finish_plug(&plug);
1358         btrfs_free_path(path);
1359         return ret < 0 ? ret : 0;
1360 }
1361
1362 static noinline_for_stack int scrub_chunk(struct scrub_dev *sdev,
1363         u64 chunk_tree, u64 chunk_objectid, u64 chunk_offset, u64 length)
1364 {
1365         struct btrfs_mapping_tree *map_tree =
1366                 &sdev->dev->dev_root->fs_info->mapping_tree;
1367         struct map_lookup *map;
1368         struct extent_map *em;
1369         int i;
1370         int ret = -EINVAL;
1371
1372         read_lock(&map_tree->map_tree.lock);
1373         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
1374         read_unlock(&map_tree->map_tree.lock);
1375
1376         if (!em)
1377                 return -EINVAL;
1378
1379         map = (struct map_lookup *)em->bdev;
1380         if (em->start != chunk_offset)
1381                 goto out;
1382
1383         if (em->len < length)
1384                 goto out;
1385
1386         for (i = 0; i < map->num_stripes; ++i) {
1387                 if (map->stripes[i].dev == sdev->dev) {
1388                         ret = scrub_stripe(sdev, map, i, chunk_offset, length);
1389                         if (ret)
1390                                 goto out;
1391                 }
1392         }
1393 out:
1394         free_extent_map(em);
1395
1396         return ret;
1397 }
1398
1399 static noinline_for_stack
1400 int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end)
1401 {
1402         struct btrfs_dev_extent *dev_extent = NULL;
1403         struct btrfs_path *path;
1404         struct btrfs_root *root = sdev->dev->dev_root;
1405         struct btrfs_fs_info *fs_info = root->fs_info;
1406         u64 length;
1407         u64 chunk_tree;
1408         u64 chunk_objectid;
1409         u64 chunk_offset;
1410         int ret;
1411         int slot;
1412         struct extent_buffer *l;
1413         struct btrfs_key key;
1414         struct btrfs_key found_key;
1415         struct btrfs_block_group_cache *cache;
1416
1417         path = btrfs_alloc_path();
1418         if (!path)
1419                 return -ENOMEM;
1420
1421         path->reada = 2;
1422         path->search_commit_root = 1;
1423         path->skip_locking = 1;
1424
1425         key.objectid = sdev->dev->devid;
1426         key.offset = 0ull;
1427         key.type = BTRFS_DEV_EXTENT_KEY;
1428
1429
1430         while (1) {
1431                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1432                 if (ret < 0)
1433                         break;
1434                 if (ret > 0) {
1435                         if (path->slots[0] >=
1436                             btrfs_header_nritems(path->nodes[0])) {
1437                                 ret = btrfs_next_leaf(root, path);
1438                                 if (ret)
1439                                         break;
1440                         }
1441                 }
1442
1443                 l = path->nodes[0];
1444                 slot = path->slots[0];
1445
1446                 btrfs_item_key_to_cpu(l, &found_key, slot);
1447
1448                 if (found_key.objectid != sdev->dev->devid)
1449                         break;
1450
1451                 if (btrfs_key_type(&found_key) != BTRFS_DEV_EXTENT_KEY)
1452                         break;
1453
1454                 if (found_key.offset >= end)
1455                         break;
1456
1457                 if (found_key.offset < key.offset)
1458                         break;
1459
1460                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1461                 length = btrfs_dev_extent_length(l, dev_extent);
1462
1463                 if (found_key.offset + length <= start) {
1464                         key.offset = found_key.offset + length;
1465                         btrfs_release_path(path);
1466                         continue;
1467                 }
1468
1469                 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
1470                 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
1471                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
1472
1473                 /*
1474                  * get a reference on the corresponding block group to prevent
1475                  * the chunk from going away while we scrub it
1476                  */
1477                 cache = btrfs_lookup_block_group(fs_info, chunk_offset);
1478                 if (!cache) {
1479                         ret = -ENOENT;
1480                         break;
1481                 }
1482                 ret = scrub_chunk(sdev, chunk_tree, chunk_objectid,
1483                                   chunk_offset, length);
1484                 btrfs_put_block_group(cache);
1485                 if (ret)
1486                         break;
1487
1488                 key.offset = found_key.offset + length;
1489                 btrfs_release_path(path);
1490         }
1491
1492         btrfs_free_path(path);
1493
1494         /*
1495          * ret can still be 1 from search_slot or next_leaf,
1496          * that's not an error
1497          */
1498         return ret < 0 ? ret : 0;
1499 }
1500
1501 static noinline_for_stack int scrub_supers(struct scrub_dev *sdev)
1502 {
1503         int     i;
1504         u64     bytenr;
1505         u64     gen;
1506         int     ret;
1507         struct btrfs_device *device = sdev->dev;
1508         struct btrfs_root *root = device->dev_root;
1509
1510         gen = root->fs_info->last_trans_committed;
1511
1512         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
1513                 bytenr = btrfs_sb_offset(i);
1514                 if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
1515                         break;
1516
1517                 ret = scrub_page(sdev, bytenr, PAGE_SIZE, bytenr,
1518                                  BTRFS_EXTENT_FLAG_SUPER, gen, i, NULL, 1);
1519                 if (ret)
1520                         return ret;
1521         }
1522         wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
1523
1524         return 0;
1525 }
1526
1527 /*
1528  * get a reference count on fs_info->scrub_workers. start worker if necessary
1529  */
1530 static noinline_for_stack int scrub_workers_get(struct btrfs_root *root)
1531 {
1532         struct btrfs_fs_info *fs_info = root->fs_info;
1533
1534         mutex_lock(&fs_info->scrub_lock);
1535         if (fs_info->scrub_workers_refcnt == 0) {
1536                 btrfs_init_workers(&fs_info->scrub_workers, "scrub",
1537                            fs_info->thread_pool_size, &fs_info->generic_worker);
1538                 fs_info->scrub_workers.idle_thresh = 4;
1539                 btrfs_start_workers(&fs_info->scrub_workers, 1);
1540         }
1541         ++fs_info->scrub_workers_refcnt;
1542         mutex_unlock(&fs_info->scrub_lock);
1543
1544         return 0;
1545 }
1546
1547 static noinline_for_stack void scrub_workers_put(struct btrfs_root *root)
1548 {
1549         struct btrfs_fs_info *fs_info = root->fs_info;
1550
1551         mutex_lock(&fs_info->scrub_lock);
1552         if (--fs_info->scrub_workers_refcnt == 0)
1553                 btrfs_stop_workers(&fs_info->scrub_workers);
1554         WARN_ON(fs_info->scrub_workers_refcnt < 0);
1555         mutex_unlock(&fs_info->scrub_lock);
1556 }
1557
1558
1559 int btrfs_scrub_dev(struct btrfs_root *root, u64 devid, u64 start, u64 end,
1560                     struct btrfs_scrub_progress *progress, int readonly)
1561 {
1562         struct scrub_dev *sdev;
1563         struct btrfs_fs_info *fs_info = root->fs_info;
1564         int ret;
1565         struct btrfs_device *dev;
1566
1567         if (btrfs_fs_closing(root->fs_info))
1568                 return -EINVAL;
1569
1570         /*
1571          * check some assumptions
1572          */
1573         if (root->sectorsize != PAGE_SIZE ||
1574             root->sectorsize != root->leafsize ||
1575             root->sectorsize != root->nodesize) {
1576                 printk(KERN_ERR "btrfs_scrub: size assumptions fail\n");
1577                 return -EINVAL;
1578         }
1579
1580         ret = scrub_workers_get(root);
1581         if (ret)
1582                 return ret;
1583
1584         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1585         dev = btrfs_find_device(root, devid, NULL, NULL);
1586         if (!dev || dev->missing) {
1587                 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1588                 scrub_workers_put(root);
1589                 return -ENODEV;
1590         }
1591         mutex_lock(&fs_info->scrub_lock);
1592
1593         if (!dev->in_fs_metadata) {
1594                 mutex_unlock(&fs_info->scrub_lock);
1595                 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1596                 scrub_workers_put(root);
1597                 return -ENODEV;
1598         }
1599
1600         if (dev->scrub_device) {
1601                 mutex_unlock(&fs_info->scrub_lock);
1602                 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1603                 scrub_workers_put(root);
1604                 return -EINPROGRESS;
1605         }
1606         sdev = scrub_setup_dev(dev);
1607         if (IS_ERR(sdev)) {
1608                 mutex_unlock(&fs_info->scrub_lock);
1609                 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1610                 scrub_workers_put(root);
1611                 return PTR_ERR(sdev);
1612         }
1613         sdev->readonly = readonly;
1614         dev->scrub_device = sdev;
1615
1616         atomic_inc(&fs_info->scrubs_running);
1617         mutex_unlock(&fs_info->scrub_lock);
1618         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1619
1620         down_read(&fs_info->scrub_super_lock);
1621         ret = scrub_supers(sdev);
1622         up_read(&fs_info->scrub_super_lock);
1623
1624         if (!ret)
1625                 ret = scrub_enumerate_chunks(sdev, start, end);
1626
1627         wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
1628         atomic_dec(&fs_info->scrubs_running);
1629         wake_up(&fs_info->scrub_pause_wait);
1630
1631         wait_event(sdev->list_wait, atomic_read(&sdev->fixup_cnt) == 0);
1632
1633         if (progress)
1634                 memcpy(progress, &sdev->stat, sizeof(*progress));
1635
1636         mutex_lock(&fs_info->scrub_lock);
1637         dev->scrub_device = NULL;
1638         mutex_unlock(&fs_info->scrub_lock);
1639
1640         scrub_free_dev(sdev);
1641         scrub_workers_put(root);
1642
1643         return ret;
1644 }
1645
1646 int btrfs_scrub_pause(struct btrfs_root *root)
1647 {
1648         struct btrfs_fs_info *fs_info = root->fs_info;
1649
1650         mutex_lock(&fs_info->scrub_lock);
1651         atomic_inc(&fs_info->scrub_pause_req);
1652         while (atomic_read(&fs_info->scrubs_paused) !=
1653                atomic_read(&fs_info->scrubs_running)) {
1654                 mutex_unlock(&fs_info->scrub_lock);
1655                 wait_event(fs_info->scrub_pause_wait,
1656                            atomic_read(&fs_info->scrubs_paused) ==
1657                            atomic_read(&fs_info->scrubs_running));
1658                 mutex_lock(&fs_info->scrub_lock);
1659         }
1660         mutex_unlock(&fs_info->scrub_lock);
1661
1662         return 0;
1663 }
1664
1665 int btrfs_scrub_continue(struct btrfs_root *root)
1666 {
1667         struct btrfs_fs_info *fs_info = root->fs_info;
1668
1669         atomic_dec(&fs_info->scrub_pause_req);
1670         wake_up(&fs_info->scrub_pause_wait);
1671         return 0;
1672 }
1673
1674 int btrfs_scrub_pause_super(struct btrfs_root *root)
1675 {
1676         down_write(&root->fs_info->scrub_super_lock);
1677         return 0;
1678 }
1679
1680 int btrfs_scrub_continue_super(struct btrfs_root *root)
1681 {
1682         up_write(&root->fs_info->scrub_super_lock);
1683         return 0;
1684 }
1685
1686 int btrfs_scrub_cancel(struct btrfs_root *root)
1687 {
1688         struct btrfs_fs_info *fs_info = root->fs_info;
1689
1690         mutex_lock(&fs_info->scrub_lock);
1691         if (!atomic_read(&fs_info->scrubs_running)) {
1692                 mutex_unlock(&fs_info->scrub_lock);
1693                 return -ENOTCONN;
1694         }
1695
1696         atomic_inc(&fs_info->scrub_cancel_req);
1697         while (atomic_read(&fs_info->scrubs_running)) {
1698                 mutex_unlock(&fs_info->scrub_lock);
1699                 wait_event(fs_info->scrub_pause_wait,
1700                            atomic_read(&fs_info->scrubs_running) == 0);
1701                 mutex_lock(&fs_info->scrub_lock);
1702         }
1703         atomic_dec(&fs_info->scrub_cancel_req);
1704         mutex_unlock(&fs_info->scrub_lock);
1705
1706         return 0;
1707 }
1708
1709 int btrfs_scrub_cancel_dev(struct btrfs_root *root, struct btrfs_device *dev)
1710 {
1711         struct btrfs_fs_info *fs_info = root->fs_info;
1712         struct scrub_dev *sdev;
1713
1714         mutex_lock(&fs_info->scrub_lock);
1715         sdev = dev->scrub_device;
1716         if (!sdev) {
1717                 mutex_unlock(&fs_info->scrub_lock);
1718                 return -ENOTCONN;
1719         }
1720         atomic_inc(&sdev->cancel_req);
1721         while (dev->scrub_device) {
1722                 mutex_unlock(&fs_info->scrub_lock);
1723                 wait_event(fs_info->scrub_pause_wait,
1724                            dev->scrub_device == NULL);
1725                 mutex_lock(&fs_info->scrub_lock);
1726         }
1727         mutex_unlock(&fs_info->scrub_lock);
1728
1729         return 0;
1730 }
1731 int btrfs_scrub_cancel_devid(struct btrfs_root *root, u64 devid)
1732 {
1733         struct btrfs_fs_info *fs_info = root->fs_info;
1734         struct btrfs_device *dev;
1735         int ret;
1736
1737         /*
1738          * we have to hold the device_list_mutex here so the device
1739          * does not go away in cancel_dev. FIXME: find a better solution
1740          */
1741         mutex_lock(&fs_info->fs_devices->device_list_mutex);
1742         dev = btrfs_find_device(root, devid, NULL, NULL);
1743         if (!dev) {
1744                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1745                 return -ENODEV;
1746         }
1747         ret = btrfs_scrub_cancel_dev(root, dev);
1748         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1749
1750         return ret;
1751 }
1752
1753 int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
1754                          struct btrfs_scrub_progress *progress)
1755 {
1756         struct btrfs_device *dev;
1757         struct scrub_dev *sdev = NULL;
1758
1759         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1760         dev = btrfs_find_device(root, devid, NULL, NULL);
1761         if (dev)
1762                 sdev = dev->scrub_device;
1763         if (sdev)
1764                 memcpy(progress, &sdev->stat, sizeof(*progress));
1765         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1766
1767         return dev ? (sdev ? 0 : -ENOTCONN) : -ENODEV;
1768 }