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Linux 3.12.5
[linux/fpc-iii.git] / fs / btrfs / scrub.c
bloba18e0e23f6a6742cd21277702ed6599df84c32c3
1 /*
2 * Copyright (C) 2011, 2012 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 #include "dev-replace.h"
29 #include "check-integrity.h"
30 #include "rcu-string.h"
31 #include "raid56.h"
32
33 /*
34 * This is only the first step towards a full-features scrub. It reads all
35 * extent and super block and verifies the checksums. In case a bad checksum
36 * is found or the extent cannot be read, good data will be written back if
37 * any can be found.
38 *
39 * Future enhancements:
40 * - In case an unrepairable extent is encountered, track which files are
41 * affected and report them
42 * - track and record media errors, throw out bad devices
43 * - add a mode to also read unallocated space
44 */
45
46 struct scrub_block;
47 struct scrub_ctx;
48
49 /*
50 * the following three values only influence the performance.
51 * The last one configures the number of parallel and outstanding I/O
52 * operations. The first two values configure an upper limit for the number
53 * of (dynamically allocated) pages that are added to a bio.
54 */
55 #define SCRUB_PAGES_PER_RD_BIO 32 /* 128k per bio */
56 #define SCRUB_PAGES_PER_WR_BIO 32 /* 128k per bio */
57 #define SCRUB_BIOS_PER_SCTX 64 /* 8MB per device in flight */
58
59 /*
60 * the following value times PAGE_SIZE needs to be large enough to match the
61 * largest node/leaf/sector size that shall be supported.
62 * Values larger than BTRFS_STRIPE_LEN are not supported.
63 */
64 #define SCRUB_MAX_PAGES_PER_BLOCK 16 /* 64k per node/leaf/sector */
65
66 struct scrub_page {
67 struct scrub_block *sblock;
68 struct page *page;
69 struct btrfs_device *dev;
70 u64 flags; /* extent flags */
71 u64 generation;
72 u64 logical;
73 u64 physical;
74 u64 physical_for_dev_replace;
75 atomic_t ref_count;
76 struct {
77 unsigned int mirror_num:8;
78 unsigned int have_csum:1;
79 unsigned int io_error:1;
80 };
81 u8 csum[BTRFS_CSUM_SIZE];
82 };
83
84 struct scrub_bio {
85 int index;
86 struct scrub_ctx *sctx;
87 struct btrfs_device *dev;
88 struct bio *bio;
89 int err;
90 u64 logical;
91 u64 physical;
92 #if SCRUB_PAGES_PER_WR_BIO >= SCRUB_PAGES_PER_RD_BIO
93 struct scrub_page *pagev[SCRUB_PAGES_PER_WR_BIO];
94 #else
95 struct scrub_page *pagev[SCRUB_PAGES_PER_RD_BIO];
96 #endif
97 int page_count;
98 int next_free;
99 struct btrfs_work work;
100 };
101
102 struct scrub_block {
103 struct scrub_page *pagev[SCRUB_MAX_PAGES_PER_BLOCK];
104 int page_count;
105 atomic_t outstanding_pages;
106 atomic_t ref_count; /* free mem on transition to zero */
107 struct scrub_ctx *sctx;
108 struct {
109 unsigned int header_error:1;
110 unsigned int checksum_error:1;
111 unsigned int no_io_error_seen:1;
112 unsigned int generation_error:1; /* also sets header_error */
113 };
114 };
115
116 struct scrub_wr_ctx {
117 struct scrub_bio *wr_curr_bio;
118 struct btrfs_device *tgtdev;
119 int pages_per_wr_bio; /* <= SCRUB_PAGES_PER_WR_BIO */
120 atomic_t flush_all_writes;
121 struct mutex wr_lock;
122 };
123
124 struct scrub_ctx {
125 struct scrub_bio *bios[SCRUB_BIOS_PER_SCTX];
126 struct btrfs_root *dev_root;
127 int first_free;
128 int curr;
129 atomic_t bios_in_flight;
130 atomic_t workers_pending;
131 spinlock_t list_lock;
132 wait_queue_head_t list_wait;
133 u16 csum_size;
134 struct list_head csum_list;
135 atomic_t cancel_req;
136 int readonly;
137 int pages_per_rd_bio;
138 u32 sectorsize;
139 u32 nodesize;
140 u32 leafsize;
141
142 int is_dev_replace;
143 struct scrub_wr_ctx wr_ctx;
144
145 /*
146 * statistics
147 */
148 struct btrfs_scrub_progress stat;
149 spinlock_t stat_lock;
150 };
151
152 struct scrub_fixup_nodatasum {
153 struct scrub_ctx *sctx;
154 struct btrfs_device *dev;
155 u64 logical;
156 struct btrfs_root *root;
157 struct btrfs_work work;
158 int mirror_num;
159 };
160
161 struct scrub_nocow_inode {
162 u64 inum;
163 u64 offset;
164 u64 root;
165 struct list_head list;
166 };
167
168 struct scrub_copy_nocow_ctx {
169 struct scrub_ctx *sctx;
170 u64 logical;
171 u64 len;
172 int mirror_num;
173 u64 physical_for_dev_replace;
174 struct list_head inodes;
175 struct btrfs_work work;
176 };
177
178 struct scrub_warning {
179 struct btrfs_path *path;
180 u64 extent_item_size;
181 char *scratch_buf;
182 char *msg_buf;
183 const char *errstr;
184 sector_t sector;
185 u64 logical;
186 struct btrfs_device *dev;
187 int msg_bufsize;
188 int scratch_bufsize;
189 };
190
191
192 static void scrub_pending_bio_inc(struct scrub_ctx *sctx);
193 static void scrub_pending_bio_dec(struct scrub_ctx *sctx);
194 static void scrub_pending_trans_workers_inc(struct scrub_ctx *sctx);
195 static void scrub_pending_trans_workers_dec(struct scrub_ctx *sctx);
196 static int scrub_handle_errored_block(struct scrub_block *sblock_to_check);
197 static int scrub_setup_recheck_block(struct scrub_ctx *sctx,
198 struct btrfs_fs_info *fs_info,
199 struct scrub_block *original_sblock,
200 u64 length, u64 logical,
201 struct scrub_block *sblocks_for_recheck);
202 static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
203 struct scrub_block *sblock, int is_metadata,
204 int have_csum, u8 *csum, u64 generation,
205 u16 csum_size);
206 static void scrub_recheck_block_checksum(struct btrfs_fs_info *fs_info,
207 struct scrub_block *sblock,
208 int is_metadata, int have_csum,
209 const u8 *csum, u64 generation,
210 u16 csum_size);
211 static void scrub_complete_bio_end_io(struct bio *bio, int err);
212 static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
213 struct scrub_block *sblock_good,
214 int force_write);
215 static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
216 struct scrub_block *sblock_good,
217 int page_num, int force_write);
218 static void scrub_write_block_to_dev_replace(struct scrub_block *sblock);
219 static int scrub_write_page_to_dev_replace(struct scrub_block *sblock,
220 int page_num);
221 static int scrub_checksum_data(struct scrub_block *sblock);
222 static int scrub_checksum_tree_block(struct scrub_block *sblock);
223 static int scrub_checksum_super(struct scrub_block *sblock);
224 static void scrub_block_get(struct scrub_block *sblock);
225 static void scrub_block_put(struct scrub_block *sblock);
226 static void scrub_page_get(struct scrub_page *spage);
227 static void scrub_page_put(struct scrub_page *spage);
228 static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx,
229 struct scrub_page *spage);
230 static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
231 u64 physical, struct btrfs_device *dev, u64 flags,
232 u64 gen, int mirror_num, u8 *csum, int force,
233 u64 physical_for_dev_replace);
234 static void scrub_bio_end_io(struct bio *bio, int err);
235 static void scrub_bio_end_io_worker(struct btrfs_work *work);
236 static void scrub_block_complete(struct scrub_block *sblock);
237 static void scrub_remap_extent(struct btrfs_fs_info *fs_info,
238 u64 extent_logical, u64 extent_len,
239 u64 *extent_physical,
240 struct btrfs_device **extent_dev,
241 int *extent_mirror_num);
242 static int scrub_setup_wr_ctx(struct scrub_ctx *sctx,
243 struct scrub_wr_ctx *wr_ctx,
244 struct btrfs_fs_info *fs_info,
245 struct btrfs_device *dev,
246 int is_dev_replace);
247 static void scrub_free_wr_ctx(struct scrub_wr_ctx *wr_ctx);
248 static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx,
249 struct scrub_page *spage);
250 static void scrub_wr_submit(struct scrub_ctx *sctx);
251 static void scrub_wr_bio_end_io(struct bio *bio, int err);
252 static void scrub_wr_bio_end_io_worker(struct btrfs_work *work);
253 static int write_page_nocow(struct scrub_ctx *sctx,
254 u64 physical_for_dev_replace, struct page *page);
255 static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root,
256 struct scrub_copy_nocow_ctx *ctx);
257 static int copy_nocow_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
258 int mirror_num, u64 physical_for_dev_replace);
259 static void copy_nocow_pages_worker(struct btrfs_work *work);
260
261
262 static void scrub_pending_bio_inc(struct scrub_ctx *sctx)
263 {
264 atomic_inc(&sctx->bios_in_flight);
265 }
266
267 static void scrub_pending_bio_dec(struct scrub_ctx *sctx)
268 {
269 atomic_dec(&sctx->bios_in_flight);
270 wake_up(&sctx->list_wait);
271 }
272
273 /*
274 * used for workers that require transaction commits (i.e., for the
275 * NOCOW case)
276 */
277 static void scrub_pending_trans_workers_inc(struct scrub_ctx *sctx)
278 {
279 struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
280
281 /*
282 * increment scrubs_running to prevent cancel requests from
283 * completing as long as a worker is running. we must also
284 * increment scrubs_paused to prevent deadlocking on pause
285 * requests used for transactions commits (as the worker uses a
286 * transaction context). it is safe to regard the worker
287 * as paused for all matters practical. effectively, we only
288 * avoid cancellation requests from completing.
289 */
290 mutex_lock(&fs_info->scrub_lock);
291 atomic_inc(&fs_info->scrubs_running);
292 atomic_inc(&fs_info->scrubs_paused);
293 mutex_unlock(&fs_info->scrub_lock);
294 atomic_inc(&sctx->workers_pending);
295 }
296
297 /* used for workers that require transaction commits */
298 static void scrub_pending_trans_workers_dec(struct scrub_ctx *sctx)
299 {
300 struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
301
302 /*
303 * see scrub_pending_trans_workers_inc() why we're pretending
304 * to be paused in the scrub counters
305 */
306 mutex_lock(&fs_info->scrub_lock);
307 atomic_dec(&fs_info->scrubs_running);
308 atomic_dec(&fs_info->scrubs_paused);
309 mutex_unlock(&fs_info->scrub_lock);
310 atomic_dec(&sctx->workers_pending);
311 wake_up(&fs_info->scrub_pause_wait);
312 wake_up(&sctx->list_wait);
313 }
314
315 static void scrub_free_csums(struct scrub_ctx *sctx)
316 {
317 while (!list_empty(&sctx->csum_list)) {
318 struct btrfs_ordered_sum *sum;
319 sum = list_first_entry(&sctx->csum_list,
320 struct btrfs_ordered_sum, list);
321 list_del(&sum->list);
322 kfree(sum);
323 }
324 }
325
326 static noinline_for_stack void scrub_free_ctx(struct scrub_ctx *sctx)
327 {
328 int i;
329
330 if (!sctx)
331 return;
332
333 scrub_free_wr_ctx(&sctx->wr_ctx);
334
335 /* this can happen when scrub is cancelled */
336 if (sctx->curr != -1) {
337 struct scrub_bio *sbio = sctx->bios[sctx->curr];
338
339 for (i = 0; i < sbio->page_count; i++) {
340 WARN_ON(!sbio->pagev[i]->page);
341 scrub_block_put(sbio->pagev[i]->sblock);
342 }
343 bio_put(sbio->bio);
344 }
345
346 for (i = 0; i < SCRUB_BIOS_PER_SCTX; ++i) {
347 struct scrub_bio *sbio = sctx->bios[i];
348
349 if (!sbio)
350 break;
351 kfree(sbio);
352 }
353
354 scrub_free_csums(sctx);
355 kfree(sctx);
356 }
357
358 static noinline_for_stack
359 struct scrub_ctx *scrub_setup_ctx(struct btrfs_device *dev, int is_dev_replace)
360 {
361 struct scrub_ctx *sctx;
362 int i;
363 struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
364 int pages_per_rd_bio;
365 int ret;
366
367 /*
368 * the setting of pages_per_rd_bio is correct for scrub but might
369 * be wrong for the dev_replace code where we might read from
370 * different devices in the initial huge bios. However, that
371 * code is able to correctly handle the case when adding a page
372 * to a bio fails.
373 */
374 if (dev->bdev)
375 pages_per_rd_bio = min_t(int, SCRUB_PAGES_PER_RD_BIO,
376 bio_get_nr_vecs(dev->bdev));
377 else
378 pages_per_rd_bio = SCRUB_PAGES_PER_RD_BIO;
379 sctx = kzalloc(sizeof(*sctx), GFP_NOFS);
380 if (!sctx)
381 goto nomem;
382 sctx->is_dev_replace = is_dev_replace;
383 sctx->pages_per_rd_bio = pages_per_rd_bio;
384 sctx->curr = -1;
385 sctx->dev_root = dev->dev_root;
386 for (i = 0; i < SCRUB_BIOS_PER_SCTX; ++i) {
387 struct scrub_bio *sbio;
388
389 sbio = kzalloc(sizeof(*sbio), GFP_NOFS);
390 if (!sbio)
391 goto nomem;
392 sctx->bios[i] = sbio;
393
394 sbio->index = i;
395 sbio->sctx = sctx;
396 sbio->page_count = 0;
397 sbio->work.func = scrub_bio_end_io_worker;
398
399 if (i != SCRUB_BIOS_PER_SCTX - 1)
400 sctx->bios[i]->next_free = i + 1;
401 else
402 sctx->bios[i]->next_free = -1;
403 }
404 sctx->first_free = 0;
405 sctx->nodesize = dev->dev_root->nodesize;
406 sctx->leafsize = dev->dev_root->leafsize;
407 sctx->sectorsize = dev->dev_root->sectorsize;
408 atomic_set(&sctx->bios_in_flight, 0);
409 atomic_set(&sctx->workers_pending, 0);
410 atomic_set(&sctx->cancel_req, 0);
411 sctx->csum_size = btrfs_super_csum_size(fs_info->super_copy);
412 INIT_LIST_HEAD(&sctx->csum_list);
413
414 spin_lock_init(&sctx->list_lock);
415 spin_lock_init(&sctx->stat_lock);
416 init_waitqueue_head(&sctx->list_wait);
417
418 ret = scrub_setup_wr_ctx(sctx, &sctx->wr_ctx, fs_info,
419 fs_info->dev_replace.tgtdev, is_dev_replace);
420 if (ret) {
421 scrub_free_ctx(sctx);
422 return ERR_PTR(ret);
423 }
424 return sctx;
425
426 nomem:
427 scrub_free_ctx(sctx);
428 return ERR_PTR(-ENOMEM);
429 }
430
431 static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root,
432 void *warn_ctx)
433 {
434 u64 isize;
435 u32 nlink;
436 int ret;
437 int i;
438 struct extent_buffer *eb;
439 struct btrfs_inode_item *inode_item;
440 struct scrub_warning *swarn = warn_ctx;
441 struct btrfs_fs_info *fs_info = swarn->dev->dev_root->fs_info;
442 struct inode_fs_paths *ipath = NULL;
443 struct btrfs_root *local_root;
444 struct btrfs_key root_key;
445
446 root_key.objectid = root;
447 root_key.type = BTRFS_ROOT_ITEM_KEY;
448 root_key.offset = (u64)-1;
449 local_root = btrfs_read_fs_root_no_name(fs_info, &root_key);
450 if (IS_ERR(local_root)) {
451 ret = PTR_ERR(local_root);
452 goto err;
453 }
454
455 ret = inode_item_info(inum, 0, local_root, swarn->path);
456 if (ret) {
457 btrfs_release_path(swarn->path);
458 goto err;
459 }
460
461 eb = swarn->path->nodes[0];
462 inode_item = btrfs_item_ptr(eb, swarn->path->slots[0],
463 struct btrfs_inode_item);
464 isize = btrfs_inode_size(eb, inode_item);
465 nlink = btrfs_inode_nlink(eb, inode_item);
466 btrfs_release_path(swarn->path);
467
468 ipath = init_ipath(4096, local_root, swarn->path);
469 if (IS_ERR(ipath)) {
470 ret = PTR_ERR(ipath);
471 ipath = NULL;
472 goto err;
473 }
474 ret = paths_from_inode(inum, ipath);
475
476 if (ret < 0)
477 goto err;
478
479 /*
480 * we deliberately ignore the bit ipath might have been too small to
481 * hold all of the paths here
482 */
483 for (i = 0; i < ipath->fspath->elem_cnt; ++i)
484 printk_in_rcu(KERN_WARNING "btrfs: %s at logical %llu on dev "
485 "%s, sector %llu, root %llu, inode %llu, offset %llu, "
486 "length %llu, links %u (path: %s)\n", swarn->errstr,
487 swarn->logical, rcu_str_deref(swarn->dev->name),
488 (unsigned long long)swarn->sector, root, inum, offset,
489 min(isize - offset, (u64)PAGE_SIZE), nlink,
490 (char *)(unsigned long)ipath->fspath->val[i]);
491
492 free_ipath(ipath);
493 return 0;
494
495 err:
496 printk_in_rcu(KERN_WARNING "btrfs: %s at logical %llu on dev "
497 "%s, sector %llu, root %llu, inode %llu, offset %llu: path "
498 "resolving failed with ret=%d\n", swarn->errstr,
499 swarn->logical, rcu_str_deref(swarn->dev->name),
500 (unsigned long long)swarn->sector, root, inum, offset, ret);
501
502 free_ipath(ipath);
503 return 0;
504 }
505
506 static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
507 {
508 struct btrfs_device *dev;
509 struct btrfs_fs_info *fs_info;
510 struct btrfs_path *path;
511 struct btrfs_key found_key;
512 struct extent_buffer *eb;
513 struct btrfs_extent_item *ei;
514 struct scrub_warning swarn;
515 unsigned long ptr = 0;
516 u64 extent_item_pos;
517 u64 flags = 0;
518 u64 ref_root;
519 u32 item_size;
520 u8 ref_level;
521 const int bufsize = 4096;
522 int ret;
523
524 WARN_ON(sblock->page_count < 1);
525 dev = sblock->pagev[0]->dev;
526 fs_info = sblock->sctx->dev_root->fs_info;
527
528 path = btrfs_alloc_path();
529
530 swarn.scratch_buf = kmalloc(bufsize, GFP_NOFS);
531 swarn.msg_buf = kmalloc(bufsize, GFP_NOFS);
532 swarn.sector = (sblock->pagev[0]->physical) >> 9;
533 swarn.logical = sblock->pagev[0]->logical;
534 swarn.errstr = errstr;
535 swarn.dev = NULL;
536 swarn.msg_bufsize = bufsize;
537 swarn.scratch_bufsize = bufsize;
538
539 if (!path || !swarn.scratch_buf || !swarn.msg_buf)
540 goto out;
541
542 ret = extent_from_logical(fs_info, swarn.logical, path, &found_key,
543 &flags);
544 if (ret < 0)
545 goto out;
546
547 extent_item_pos = swarn.logical - found_key.objectid;
548 swarn.extent_item_size = found_key.offset;
549
550 eb = path->nodes[0];
551 ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
552 item_size = btrfs_item_size_nr(eb, path->slots[0]);
553
554 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
555 do {
556 ret = tree_backref_for_extent(&ptr, eb, ei, item_size,
557 &ref_root, &ref_level);
558 printk_in_rcu(KERN_WARNING
559 "btrfs: %s at logical %llu on dev %s, "
560 "sector %llu: metadata %s (level %d) in tree "
561 "%llu\n", errstr, swarn.logical,
562 rcu_str_deref(dev->name),
563 (unsigned long long)swarn.sector,
564 ref_level ? "node" : "leaf",
565 ret < 0 ? -1 : ref_level,
566 ret < 0 ? -1 : ref_root);
567 } while (ret != 1);
568 btrfs_release_path(path);
569 } else {
570 btrfs_release_path(path);
571 swarn.path = path;
572 swarn.dev = dev;
573 iterate_extent_inodes(fs_info, found_key.objectid,
574 extent_item_pos, 1,
575 scrub_print_warning_inode, &swarn);
576 }
577
578 out:
579 btrfs_free_path(path);
580 kfree(swarn.scratch_buf);
581 kfree(swarn.msg_buf);
582 }
583
584 static int scrub_fixup_readpage(u64 inum, u64 offset, u64 root, void *fixup_ctx)
585 {
586 struct page *page = NULL;
587 unsigned long index;
588 struct scrub_fixup_nodatasum *fixup = fixup_ctx;
589 int ret;
590 int corrected = 0;
591 struct btrfs_key key;
592 struct inode *inode = NULL;
593 struct btrfs_fs_info *fs_info;
594 u64 end = offset + PAGE_SIZE - 1;
595 struct btrfs_root *local_root;
596 int srcu_index;
597
598 key.objectid = root;
599 key.type = BTRFS_ROOT_ITEM_KEY;
600 key.offset = (u64)-1;
601
602 fs_info = fixup->root->fs_info;
603 srcu_index = srcu_read_lock(&fs_info->subvol_srcu);
604
605 local_root = btrfs_read_fs_root_no_name(fs_info, &key);
606 if (IS_ERR(local_root)) {
607 srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
608 return PTR_ERR(local_root);
609 }
610
611 key.type = BTRFS_INODE_ITEM_KEY;
612 key.objectid = inum;
613 key.offset = 0;
614 inode = btrfs_iget(fs_info->sb, &key, local_root, NULL);
615 srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
616 if (IS_ERR(inode))
617 return PTR_ERR(inode);
618
619 index = offset >> PAGE_CACHE_SHIFT;
620
621 page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
622 if (!page) {
623 ret = -ENOMEM;
624 goto out;
625 }
626
627 if (PageUptodate(page)) {
628 if (PageDirty(page)) {
629 /*
630 * we need to write the data to the defect sector. the
631 * data that was in that sector is not in memory,
632 * because the page was modified. we must not write the
633 * modified page to that sector.
634 *
635 * TODO: what could be done here: wait for the delalloc
636 * runner to write out that page (might involve
637 * COW) and see whether the sector is still
638 * referenced afterwards.
639 *
640 * For the meantime, we'll treat this error
641 * incorrectable, although there is a chance that a
642 * later scrub will find the bad sector again and that
643 * there's no dirty page in memory, then.
644 */
645 ret = -EIO;
646 goto out;
647 }
648 fs_info = BTRFS_I(inode)->root->fs_info;
649 ret = repair_io_failure(fs_info, offset, PAGE_SIZE,
650 fixup->logical, page,
651 fixup->mirror_num);
652 unlock_page(page);
653 corrected = !ret;
654 } else {
655 /*
656 * we need to get good data first. the general readpage path
657 * will call repair_io_failure for us, we just have to make
658 * sure we read the bad mirror.
659 */
660 ret = set_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
661 EXTENT_DAMAGED, GFP_NOFS);
662 if (ret) {
663 /* set_extent_bits should give proper error */
664 WARN_ON(ret > 0);
665 if (ret > 0)
666 ret = -EFAULT;
667 goto out;
668 }
669
670 ret = extent_read_full_page(&BTRFS_I(inode)->io_tree, page,
671 btrfs_get_extent,
672 fixup->mirror_num);
673 wait_on_page_locked(page);
674
675 corrected = !test_range_bit(&BTRFS_I(inode)->io_tree, offset,
676 end, EXTENT_DAMAGED, 0, NULL);
677 if (!corrected)
678 clear_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
679 EXTENT_DAMAGED, GFP_NOFS);
680 }
681
682 out:
683 if (page)
684 put_page(page);
685 if (inode)
686 iput(inode);
687
688 if (ret < 0)
689 return ret;
690
691 if (ret == 0 && corrected) {
692 /*
693 * we only need to call readpage for one of the inodes belonging
694 * to this extent. so make iterate_extent_inodes stop
695 */
696 return 1;
697 }
698
699 return -EIO;
700 }
701
702 static void scrub_fixup_nodatasum(struct btrfs_work *work)
703 {
704 int ret;
705 struct scrub_fixup_nodatasum *fixup;
706 struct scrub_ctx *sctx;
707 struct btrfs_trans_handle *trans = NULL;
708 struct btrfs_fs_info *fs_info;
709 struct btrfs_path *path;
710 int uncorrectable = 0;
711
712 fixup = container_of(work, struct scrub_fixup_nodatasum, work);
713 sctx = fixup->sctx;
714 fs_info = fixup->root->fs_info;
715
716 path = btrfs_alloc_path();
717 if (!path) {
718 spin_lock(&sctx->stat_lock);
719 ++sctx->stat.malloc_errors;
720 spin_unlock(&sctx->stat_lock);
721 uncorrectable = 1;
722 goto out;
723 }
724
725 trans = btrfs_join_transaction(fixup->root);
726 if (IS_ERR(trans)) {
727 uncorrectable = 1;
728 goto out;
729 }
730
731 /*
732 * the idea is to trigger a regular read through the standard path. we
733 * read a page from the (failed) logical address by specifying the
734 * corresponding copynum of the failed sector. thus, that readpage is
735 * expected to fail.
736 * that is the point where on-the-fly error correction will kick in
737 * (once it's finished) and rewrite the failed sector if a good copy
738 * can be found.
739 */
740 ret = iterate_inodes_from_logical(fixup->logical, fixup->root->fs_info,
741 path, scrub_fixup_readpage,
742 fixup);
743 if (ret < 0) {
744 uncorrectable = 1;
745 goto out;
746 }
747 WARN_ON(ret != 1);
748
749 spin_lock(&sctx->stat_lock);
750 ++sctx->stat.corrected_errors;
751 spin_unlock(&sctx->stat_lock);
752
753 out:
754 if (trans && !IS_ERR(trans))
755 btrfs_end_transaction(trans, fixup->root);
756 if (uncorrectable) {
757 spin_lock(&sctx->stat_lock);
758 ++sctx->stat.uncorrectable_errors;
759 spin_unlock(&sctx->stat_lock);
760 btrfs_dev_replace_stats_inc(
761 &sctx->dev_root->fs_info->dev_replace.
762 num_uncorrectable_read_errors);
763 printk_ratelimited_in_rcu(KERN_ERR
764 "btrfs: unable to fixup (nodatasum) error at logical %llu on dev %s\n",
765 fixup->logical, rcu_str_deref(fixup->dev->name));
766 }
767
768 btrfs_free_path(path);
769 kfree(fixup);
770
771 scrub_pending_trans_workers_dec(sctx);
772 }
773
774 /*
775 * scrub_handle_errored_block gets called when either verification of the
776 * pages failed or the bio failed to read, e.g. with EIO. In the latter
777 * case, this function handles all pages in the bio, even though only one
778 * may be bad.
779 * The goal of this function is to repair the errored block by using the
780 * contents of one of the mirrors.
781 */
782 static int scrub_handle_errored_block(struct scrub_block *sblock_to_check)
783 {
784 struct scrub_ctx *sctx = sblock_to_check->sctx;
785 struct btrfs_device *dev;
786 struct btrfs_fs_info *fs_info;
787 u64 length;
788 u64 logical;
789 u64 generation;
790 unsigned int failed_mirror_index;
791 unsigned int is_metadata;
792 unsigned int have_csum;
793 u8 *csum;
794 struct scrub_block *sblocks_for_recheck; /* holds one for each mirror */
795 struct scrub_block *sblock_bad;
796 int ret;
797 int mirror_index;
798 int page_num;
799 int success;
800 static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
801 DEFAULT_RATELIMIT_BURST);
802
803 BUG_ON(sblock_to_check->page_count < 1);
804 fs_info = sctx->dev_root->fs_info;
805 if (sblock_to_check->pagev[0]->flags & BTRFS_EXTENT_FLAG_SUPER) {
806 /*
807 * if we find an error in a super block, we just report it.
808 * They will get written with the next transaction commit
809 * anyway
810 */
811 spin_lock(&sctx->stat_lock);
812 ++sctx->stat.super_errors;
813 spin_unlock(&sctx->stat_lock);
814 return 0;
815 }
816 length = sblock_to_check->page_count * PAGE_SIZE;
817 logical = sblock_to_check->pagev[0]->logical;
818 generation = sblock_to_check->pagev[0]->generation;
819 BUG_ON(sblock_to_check->pagev[0]->mirror_num < 1);
820 failed_mirror_index = sblock_to_check->pagev[0]->mirror_num - 1;
821 is_metadata = !(sblock_to_check->pagev[0]->flags &
822 BTRFS_EXTENT_FLAG_DATA);
823 have_csum = sblock_to_check->pagev[0]->have_csum;
824 csum = sblock_to_check->pagev[0]->csum;
825 dev = sblock_to_check->pagev[0]->dev;
826
827 if (sctx->is_dev_replace && !is_metadata && !have_csum) {
828 sblocks_for_recheck = NULL;
829 goto nodatasum_case;
830 }
831
832 /*
833 * read all mirrors one after the other. This includes to
834 * re-read the extent or metadata block that failed (that was
835 * the cause that this fixup code is called) another time,
836 * page by page this time in order to know which pages
837 * caused I/O errors and which ones are good (for all mirrors).
838 * It is the goal to handle the situation when more than one
839 * mirror contains I/O errors, but the errors do not
840 * overlap, i.e. the data can be repaired by selecting the
841 * pages from those mirrors without I/O error on the
842 * particular pages. One example (with blocks >= 2 * PAGE_SIZE)
843 * would be that mirror #1 has an I/O error on the first page,
844 * the second page is good, and mirror #2 has an I/O error on
845 * the second page, but the first page is good.
846 * Then the first page of the first mirror can be repaired by
847 * taking the first page of the second mirror, and the
848 * second page of the second mirror can be repaired by
849 * copying the contents of the 2nd page of the 1st mirror.
850 * One more note: if the pages of one mirror contain I/O
851 * errors, the checksum cannot be verified. In order to get
852 * the best data for repairing, the first attempt is to find
853 * a mirror without I/O errors and with a validated checksum.
854 * Only if this is not possible, the pages are picked from
855 * mirrors with I/O errors without considering the checksum.
856 * If the latter is the case, at the end, the checksum of the
857 * repaired area is verified in order to correctly maintain
858 * the statistics.
859 */
860
861 sblocks_for_recheck = kzalloc(BTRFS_MAX_MIRRORS *
862 sizeof(*sblocks_for_recheck),
863 GFP_NOFS);
864 if (!sblocks_for_recheck) {
865 spin_lock(&sctx->stat_lock);
866 sctx->stat.malloc_errors++;
867 sctx->stat.read_errors++;
868 sctx->stat.uncorrectable_errors++;
869 spin_unlock(&sctx->stat_lock);
870 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
871 goto out;
872 }
873
874 /* setup the context, map the logical blocks and alloc the pages */
875 ret = scrub_setup_recheck_block(sctx, fs_info, sblock_to_check, length,
876 logical, sblocks_for_recheck);
877 if (ret) {
878 spin_lock(&sctx->stat_lock);
879 sctx->stat.read_errors++;
880 sctx->stat.uncorrectable_errors++;
881 spin_unlock(&sctx->stat_lock);
882 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
883 goto out;
884 }
885 BUG_ON(failed_mirror_index >= BTRFS_MAX_MIRRORS);
886 sblock_bad = sblocks_for_recheck + failed_mirror_index;
887
888 /* build and submit the bios for the failed mirror, check checksums */
889 scrub_recheck_block(fs_info, sblock_bad, is_metadata, have_csum,
890 csum, generation, sctx->csum_size);
891
892 if (!sblock_bad->header_error && !sblock_bad->checksum_error &&
893 sblock_bad->no_io_error_seen) {
894 /*
895 * the error disappeared after reading page by page, or
896 * the area was part of a huge bio and other parts of the
897 * bio caused I/O errors, or the block layer merged several
898 * read requests into one and the error is caused by a
899 * different bio (usually one of the two latter cases is
900 * the cause)
901 */
902 spin_lock(&sctx->stat_lock);
903 sctx->stat.unverified_errors++;
904 spin_unlock(&sctx->stat_lock);
905
906 if (sctx->is_dev_replace)
907 scrub_write_block_to_dev_replace(sblock_bad);
908 goto out;
909 }
910
911 if (!sblock_bad->no_io_error_seen) {
912 spin_lock(&sctx->stat_lock);
913 sctx->stat.read_errors++;
914 spin_unlock(&sctx->stat_lock);
915 if (__ratelimit(&_rs))
916 scrub_print_warning("i/o error", sblock_to_check);
917 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
918 } else if (sblock_bad->checksum_error) {
919 spin_lock(&sctx->stat_lock);
920 sctx->stat.csum_errors++;
921 spin_unlock(&sctx->stat_lock);
922 if (__ratelimit(&_rs))
923 scrub_print_warning("checksum error", sblock_to_check);
924 btrfs_dev_stat_inc_and_print(dev,
925 BTRFS_DEV_STAT_CORRUPTION_ERRS);
926 } else if (sblock_bad->header_error) {
927 spin_lock(&sctx->stat_lock);
928 sctx->stat.verify_errors++;
929 spin_unlock(&sctx->stat_lock);
930 if (__ratelimit(&_rs))
931 scrub_print_warning("checksum/header error",
932 sblock_to_check);
933 if (sblock_bad->generation_error)
934 btrfs_dev_stat_inc_and_print(dev,
935 BTRFS_DEV_STAT_GENERATION_ERRS);
936 else
937 btrfs_dev_stat_inc_and_print(dev,
938 BTRFS_DEV_STAT_CORRUPTION_ERRS);
939 }
940
941 if (sctx->readonly && !sctx->is_dev_replace)
942 goto did_not_correct_error;
943
944 if (!is_metadata && !have_csum) {
945 struct scrub_fixup_nodatasum *fixup_nodatasum;
946
947 nodatasum_case:
948 WARN_ON(sctx->is_dev_replace);
949
950 /*
951 * !is_metadata and !have_csum, this means that the data
952 * might not be COW'ed, that it might be modified
953 * concurrently. The general strategy to work on the
954 * commit root does not help in the case when COW is not
955 * used.
956 */
957 fixup_nodatasum = kzalloc(sizeof(*fixup_nodatasum), GFP_NOFS);
958 if (!fixup_nodatasum)
959 goto did_not_correct_error;
960 fixup_nodatasum->sctx = sctx;
961 fixup_nodatasum->dev = dev;
962 fixup_nodatasum->logical = logical;
963 fixup_nodatasum->root = fs_info->extent_root;
964 fixup_nodatasum->mirror_num = failed_mirror_index + 1;
965 scrub_pending_trans_workers_inc(sctx);
966 fixup_nodatasum->work.func = scrub_fixup_nodatasum;
967 btrfs_queue_worker(&fs_info->scrub_workers,
968 &fixup_nodatasum->work);
969 goto out;
970 }
971
972 /*
973 * now build and submit the bios for the other mirrors, check
974 * checksums.
975 * First try to pick the mirror which is completely without I/O
976 * errors and also does not have a checksum error.
977 * If one is found, and if a checksum is present, the full block
978 * that is known to contain an error is rewritten. Afterwards
979 * the block is known to be corrected.
980 * If a mirror is found which is completely correct, and no
981 * checksum is present, only those pages are rewritten that had
982 * an I/O error in the block to be repaired, since it cannot be
983 * determined, which copy of the other pages is better (and it
984 * could happen otherwise that a correct page would be
985 * overwritten by a bad one).
986 */
987 for (mirror_index = 0;
988 mirror_index < BTRFS_MAX_MIRRORS &&
989 sblocks_for_recheck[mirror_index].page_count > 0;
990 mirror_index++) {
991 struct scrub_block *sblock_other;
992
993 if (mirror_index == failed_mirror_index)
994 continue;
995 sblock_other = sblocks_for_recheck + mirror_index;
996
997 /* build and submit the bios, check checksums */
998 scrub_recheck_block(fs_info, sblock_other, is_metadata,
999 have_csum, csum, generation,
1000 sctx->csum_size);
1001
1002 if (!sblock_other->header_error &&
1003 !sblock_other->checksum_error &&
1004 sblock_other->no_io_error_seen) {
1005 if (sctx->is_dev_replace) {
1006 scrub_write_block_to_dev_replace(sblock_other);
1007 } else {
1008 int force_write = is_metadata || have_csum;
1009
1010 ret = scrub_repair_block_from_good_copy(
1011 sblock_bad, sblock_other,
1012 force_write);
1013 }
1014 if (0 == ret)
1015 goto corrected_error;
1016 }
1017 }
1018
1019 /*
1020 * for dev_replace, pick good pages and write to the target device.
1021 */
1022 if (sctx->is_dev_replace) {
1023 success = 1;
1024 for (page_num = 0; page_num < sblock_bad->page_count;
1025 page_num++) {
1026 int sub_success;
1027
1028 sub_success = 0;
1029 for (mirror_index = 0;
1030 mirror_index < BTRFS_MAX_MIRRORS &&
1031 sblocks_for_recheck[mirror_index].page_count > 0;
1032 mirror_index++) {
1033 struct scrub_block *sblock_other =
1034 sblocks_for_recheck + mirror_index;
1035 struct scrub_page *page_other =
1036 sblock_other->pagev[page_num];
1037
1038 if (!page_other->io_error) {
1039 ret = scrub_write_page_to_dev_replace(
1040 sblock_other, page_num);
1041 if (ret == 0) {
1042 /* succeeded for this page */
1043 sub_success = 1;
1044 break;
1045 } else {
1046 btrfs_dev_replace_stats_inc(
1047 &sctx->dev_root->
1048 fs_info->dev_replace.
1049 num_write_errors);
1050 }
1051 }
1052 }
1053
1054 if (!sub_success) {
1055 /*
1056 * did not find a mirror to fetch the page
1057 * from. scrub_write_page_to_dev_replace()
1058 * handles this case (page->io_error), by
1059 * filling the block with zeros before
1060 * submitting the write request
1061 */
1062 success = 0;
1063 ret = scrub_write_page_to_dev_replace(
1064 sblock_bad, page_num);
1065 if (ret)
1066 btrfs_dev_replace_stats_inc(
1067 &sctx->dev_root->fs_info->
1068 dev_replace.num_write_errors);
1069 }
1070 }
1071
1072 goto out;
1073 }
1074
1075 /*
1076 * for regular scrub, repair those pages that are errored.
1077 * In case of I/O errors in the area that is supposed to be
1078 * repaired, continue by picking good copies of those pages.
1079 * Select the good pages from mirrors to rewrite bad pages from
1080 * the area to fix. Afterwards verify the checksum of the block
1081 * that is supposed to be repaired. This verification step is
1082 * only done for the purpose of statistic counting and for the
1083 * final scrub report, whether errors remain.
1084 * A perfect algorithm could make use of the checksum and try
1085 * all possible combinations of pages from the different mirrors
1086 * until the checksum verification succeeds. For example, when
1087 * the 2nd page of mirror #1 faces I/O errors, and the 2nd page
1088 * of mirror #2 is readable but the final checksum test fails,
1089 * then the 2nd page of mirror #3 could be tried, whether now
1090 * the final checksum succeedes. But this would be a rare
1091 * exception and is therefore not implemented. At least it is
1092 * avoided that the good copy is overwritten.
1093 * A more useful improvement would be to pick the sectors
1094 * without I/O error based on sector sizes (512 bytes on legacy
1095 * disks) instead of on PAGE_SIZE. Then maybe 512 byte of one
1096 * mirror could be repaired by taking 512 byte of a different
1097 * mirror, even if other 512 byte sectors in the same PAGE_SIZE
1098 * area are unreadable.
1099 */
1100
1101 /* can only fix I/O errors from here on */
1102 if (sblock_bad->no_io_error_seen)
1103 goto did_not_correct_error;
1104
1105 success = 1;
1106 for (page_num = 0; page_num < sblock_bad->page_count; page_num++) {
1107 struct scrub_page *page_bad = sblock_bad->pagev[page_num];
1108
1109 if (!page_bad->io_error)
1110 continue;
1111
1112 for (mirror_index = 0;
1113 mirror_index < BTRFS_MAX_MIRRORS &&
1114 sblocks_for_recheck[mirror_index].page_count > 0;
1115 mirror_index++) {
1116 struct scrub_block *sblock_other = sblocks_for_recheck +
1117 mirror_index;
1118 struct scrub_page *page_other = sblock_other->pagev[
1119 page_num];
1120
1121 if (!page_other->io_error) {
1122 ret = scrub_repair_page_from_good_copy(
1123 sblock_bad, sblock_other, page_num, 0);
1124 if (0 == ret) {
1125 page_bad->io_error = 0;
1126 break; /* succeeded for this page */
1127 }
1128 }
1129 }
1130
1131 if (page_bad->io_error) {
1132 /* did not find a mirror to copy the page from */
1133 success = 0;
1134 }
1135 }
1136
1137 if (success) {
1138 if (is_metadata || have_csum) {
1139 /*
1140 * need to verify the checksum now that all
1141 * sectors on disk are repaired (the write
1142 * request for data to be repaired is on its way).
1143 * Just be lazy and use scrub_recheck_block()
1144 * which re-reads the data before the checksum
1145 * is verified, but most likely the data comes out
1146 * of the page cache.
1147 */
1148 scrub_recheck_block(fs_info, sblock_bad,
1149 is_metadata, have_csum, csum,
1150 generation, sctx->csum_size);
1151 if (!sblock_bad->header_error &&
1152 !sblock_bad->checksum_error &&
1153 sblock_bad->no_io_error_seen)
1154 goto corrected_error;
1155 else
1156 goto did_not_correct_error;
1157 } else {
1158 corrected_error:
1159 spin_lock(&sctx->stat_lock);
1160 sctx->stat.corrected_errors++;
1161 spin_unlock(&sctx->stat_lock);
1162 printk_ratelimited_in_rcu(KERN_ERR
1163 "btrfs: fixed up error at logical %llu on dev %s\n",
1164 logical, rcu_str_deref(dev->name));
1165 }
1166 } else {
1167 did_not_correct_error:
1168 spin_lock(&sctx->stat_lock);
1169 sctx->stat.uncorrectable_errors++;
1170 spin_unlock(&sctx->stat_lock);
1171 printk_ratelimited_in_rcu(KERN_ERR
1172 "btrfs: unable to fixup (regular) error at logical %llu on dev %s\n",
1173 logical, rcu_str_deref(dev->name));
1174 }
1175
1176 out:
1177 if (sblocks_for_recheck) {
1178 for (mirror_index = 0; mirror_index < BTRFS_MAX_MIRRORS;
1179 mirror_index++) {
1180 struct scrub_block *sblock = sblocks_for_recheck +
1181 mirror_index;
1182 int page_index;
1183
1184 for (page_index = 0; page_index < sblock->page_count;
1185 page_index++) {
1186 sblock->pagev[page_index]->sblock = NULL;
1187 scrub_page_put(sblock->pagev[page_index]);
1188 }
1189 }
1190 kfree(sblocks_for_recheck);
1191 }
1192
1193 return 0;
1194 }
1195
1196 static int scrub_setup_recheck_block(struct scrub_ctx *sctx,
1197 struct btrfs_fs_info *fs_info,
1198 struct scrub_block *original_sblock,
1199 u64 length, u64 logical,
1200 struct scrub_block *sblocks_for_recheck)
1201 {
1202 int page_index;
1203 int mirror_index;
1204 int ret;
1205
1206 /*
1207 * note: the two members ref_count and outstanding_pages
1208 * are not used (and not set) in the blocks that are used for
1209 * the recheck procedure
1210 */
1211
1212 page_index = 0;
1213 while (length > 0) {
1214 u64 sublen = min_t(u64, length, PAGE_SIZE);
1215 u64 mapped_length = sublen;
1216 struct btrfs_bio *bbio = NULL;
1217
1218 /*
1219 * with a length of PAGE_SIZE, each returned stripe
1220 * represents one mirror
1221 */
1222 ret = btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS, logical,
1223 &mapped_length, &bbio, 0);
1224 if (ret || !bbio || mapped_length < sublen) {
1225 kfree(bbio);
1226 return -EIO;
1227 }
1228
1229 BUG_ON(page_index >= SCRUB_PAGES_PER_RD_BIO);
1230 for (mirror_index = 0; mirror_index < (int)bbio->num_stripes;
1231 mirror_index++) {
1232 struct scrub_block *sblock;
1233 struct scrub_page *page;
1234
1235 if (mirror_index >= BTRFS_MAX_MIRRORS)
1236 continue;
1237
1238 sblock = sblocks_for_recheck + mirror_index;
1239 sblock->sctx = sctx;
1240 page = kzalloc(sizeof(*page), GFP_NOFS);
1241 if (!page) {
1242 leave_nomem:
1243 spin_lock(&sctx->stat_lock);
1244 sctx->stat.malloc_errors++;
1245 spin_unlock(&sctx->stat_lock);
1246 kfree(bbio);
1247 return -ENOMEM;
1248 }
1249 scrub_page_get(page);
1250 sblock->pagev[page_index] = page;
1251 page->logical = logical;
1252 page->physical = bbio->stripes[mirror_index].physical;
1253 BUG_ON(page_index >= original_sblock->page_count);
1254 page->physical_for_dev_replace =
1255 original_sblock->pagev[page_index]->
1256 physical_for_dev_replace;
1257 /* for missing devices, dev->bdev is NULL */
1258 page->dev = bbio->stripes[mirror_index].dev;
1259 page->mirror_num = mirror_index + 1;
1260 sblock->page_count++;
1261 page->page = alloc_page(GFP_NOFS);
1262 if (!page->page)
1263 goto leave_nomem;
1264 }
1265 kfree(bbio);
1266 length -= sublen;
1267 logical += sublen;
1268 page_index++;
1269 }
1270
1271 return 0;
1272 }
1273
1274 /*
1275 * this function will check the on disk data for checksum errors, header
1276 * errors and read I/O errors. If any I/O errors happen, the exact pages
1277 * which are errored are marked as being bad. The goal is to enable scrub
1278 * to take those pages that are not errored from all the mirrors so that
1279 * the pages that are errored in the just handled mirror can be repaired.
1280 */
1281 static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
1282 struct scrub_block *sblock, int is_metadata,
1283 int have_csum, u8 *csum, u64 generation,
1284 u16 csum_size)
1285 {
1286 int page_num;
1287
1288 sblock->no_io_error_seen = 1;
1289 sblock->header_error = 0;
1290 sblock->checksum_error = 0;
1291
1292 for (page_num = 0; page_num < sblock->page_count; page_num++) {
1293 struct bio *bio;
1294 struct scrub_page *page = sblock->pagev[page_num];
1295 DECLARE_COMPLETION_ONSTACK(complete);
1296
1297 if (page->dev->bdev == NULL) {
1298 page->io_error = 1;
1299 sblock->no_io_error_seen = 0;
1300 continue;
1301 }
1302
1303 WARN_ON(!page->page);
1304 bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
1305 if (!bio) {
1306 page->io_error = 1;
1307 sblock->no_io_error_seen = 0;
1308 continue;
1309 }
1310 bio->bi_bdev = page->dev->bdev;
1311 bio->bi_sector = page->physical >> 9;
1312 bio->bi_end_io = scrub_complete_bio_end_io;
1313 bio->bi_private = &complete;
1314
1315 bio_add_page(bio, page->page, PAGE_SIZE, 0);
1316 btrfsic_submit_bio(READ, bio);
1317
1318 /* this will also unplug the queue */
1319 wait_for_completion(&complete);
1320
1321 page->io_error = !test_bit(BIO_UPTODATE, &bio->bi_flags);
1322 if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
1323 sblock->no_io_error_seen = 0;
1324 bio_put(bio);
1325 }
1326
1327 if (sblock->no_io_error_seen)
1328 scrub_recheck_block_checksum(fs_info, sblock, is_metadata,
1329 have_csum, csum, generation,
1330 csum_size);
1331
1332 return;
1333 }
1334
1335 static void scrub_recheck_block_checksum(struct btrfs_fs_info *fs_info,
1336 struct scrub_block *sblock,
1337 int is_metadata, int have_csum,
1338 const u8 *csum, u64 generation,
1339 u16 csum_size)
1340 {
1341 int page_num;
1342 u8 calculated_csum[BTRFS_CSUM_SIZE];
1343 u32 crc = ~(u32)0;
1344 void *mapped_buffer;
1345
1346 WARN_ON(!sblock->pagev[0]->page);
1347 if (is_metadata) {
1348 struct btrfs_header *h;
1349
1350 mapped_buffer = kmap_atomic(sblock->pagev[0]->page);
1351 h = (struct btrfs_header *)mapped_buffer;
1352
1353 if (sblock->pagev[0]->logical != btrfs_stack_header_bytenr(h) ||
1354 memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE) ||
1355 memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
1356 BTRFS_UUID_SIZE)) {
1357 sblock->header_error = 1;
1358 } else if (generation != btrfs_stack_header_generation(h)) {
1359 sblock->header_error = 1;
1360 sblock->generation_error = 1;
1361 }
1362 csum = h->csum;
1363 } else {
1364 if (!have_csum)
1365 return;
1366
1367 mapped_buffer = kmap_atomic(sblock->pagev[0]->page);
1368 }
1369
1370 for (page_num = 0;;) {
1371 if (page_num == 0 && is_metadata)
1372 crc = btrfs_csum_data(
1373 ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE,
1374 crc, PAGE_SIZE - BTRFS_CSUM_SIZE);
1375 else
1376 crc = btrfs_csum_data(mapped_buffer, crc, PAGE_SIZE);
1377
1378 kunmap_atomic(mapped_buffer);
1379 page_num++;
1380 if (page_num >= sblock->page_count)
1381 break;
1382 WARN_ON(!sblock->pagev[page_num]->page);
1383
1384 mapped_buffer = kmap_atomic(sblock->pagev[page_num]->page);
1385 }
1386
1387 btrfs_csum_final(crc, calculated_csum);
1388 if (memcmp(calculated_csum, csum, csum_size))
1389 sblock->checksum_error = 1;
1390 }
1391
1392 static void scrub_complete_bio_end_io(struct bio *bio, int err)
1393 {
1394 complete((struct completion *)bio->bi_private);
1395 }
1396
1397 static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
1398 struct scrub_block *sblock_good,
1399 int force_write)
1400 {
1401 int page_num;
1402 int ret = 0;
1403
1404 for (page_num = 0; page_num < sblock_bad->page_count; page_num++) {
1405 int ret_sub;
1406
1407 ret_sub = scrub_repair_page_from_good_copy(sblock_bad,
1408 sblock_good,
1409 page_num,
1410 force_write);
1411 if (ret_sub)
1412 ret = ret_sub;
1413 }
1414
1415 return ret;
1416 }
1417
1418 static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
1419 struct scrub_block *sblock_good,
1420 int page_num, int force_write)
1421 {
1422 struct scrub_page *page_bad = sblock_bad->pagev[page_num];
1423 struct scrub_page *page_good = sblock_good->pagev[page_num];
1424
1425 BUG_ON(page_bad->page == NULL);
1426 BUG_ON(page_good->page == NULL);
1427 if (force_write || sblock_bad->header_error ||
1428 sblock_bad->checksum_error || page_bad->io_error) {
1429 struct bio *bio;
1430 int ret;
1431 DECLARE_COMPLETION_ONSTACK(complete);
1432
1433 if (!page_bad->dev->bdev) {
1434 printk_ratelimited(KERN_WARNING
1435 "btrfs: scrub_repair_page_from_good_copy(bdev == NULL) is unexpected!\n");
1436 return -EIO;
1437 }
1438
1439 bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
1440 if (!bio)
1441 return -EIO;
1442 bio->bi_bdev = page_bad->dev->bdev;
1443 bio->bi_sector = page_bad->physical >> 9;
1444 bio->bi_end_io = scrub_complete_bio_end_io;
1445 bio->bi_private = &complete;
1446
1447 ret = bio_add_page(bio, page_good->page, PAGE_SIZE, 0);
1448 if (PAGE_SIZE != ret) {
1449 bio_put(bio);
1450 return -EIO;
1451 }
1452 btrfsic_submit_bio(WRITE, bio);
1453
1454 /* this will also unplug the queue */
1455 wait_for_completion(&complete);
1456 if (!bio_flagged(bio, BIO_UPTODATE)) {
1457 btrfs_dev_stat_inc_and_print(page_bad->dev,
1458 BTRFS_DEV_STAT_WRITE_ERRS);
1459 btrfs_dev_replace_stats_inc(
1460 &sblock_bad->sctx->dev_root->fs_info->
1461 dev_replace.num_write_errors);
1462 bio_put(bio);
1463 return -EIO;
1464 }
1465 bio_put(bio);
1466 }
1467
1468 return 0;
1469 }
1470
1471 static void scrub_write_block_to_dev_replace(struct scrub_block *sblock)
1472 {
1473 int page_num;
1474
1475 for (page_num = 0; page_num < sblock->page_count; page_num++) {
1476 int ret;
1477
1478 ret = scrub_write_page_to_dev_replace(sblock, page_num);
1479 if (ret)
1480 btrfs_dev_replace_stats_inc(
1481 &sblock->sctx->dev_root->fs_info->dev_replace.
1482 num_write_errors);
1483 }
1484 }
1485
1486 static int scrub_write_page_to_dev_replace(struct scrub_block *sblock,
1487 int page_num)
1488 {
1489 struct scrub_page *spage = sblock->pagev[page_num];
1490
1491 BUG_ON(spage->page == NULL);
1492 if (spage->io_error) {
1493 void *mapped_buffer = kmap_atomic(spage->page);
1494
1495 memset(mapped_buffer, 0, PAGE_CACHE_SIZE);
1496 flush_dcache_page(spage->page);
1497 kunmap_atomic(mapped_buffer);
1498 }
1499 return scrub_add_page_to_wr_bio(sblock->sctx, spage);
1500 }
1501
1502 static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx,
1503 struct scrub_page *spage)
1504 {
1505 struct scrub_wr_ctx *wr_ctx = &sctx->wr_ctx;
1506 struct scrub_bio *sbio;
1507 int ret;
1508
1509 mutex_lock(&wr_ctx->wr_lock);
1510 again:
1511 if (!wr_ctx->wr_curr_bio) {
1512 wr_ctx->wr_curr_bio = kzalloc(sizeof(*wr_ctx->wr_curr_bio),
1513 GFP_NOFS);
1514 if (!wr_ctx->wr_curr_bio) {
1515 mutex_unlock(&wr_ctx->wr_lock);
1516 return -ENOMEM;
1517 }
1518 wr_ctx->wr_curr_bio->sctx = sctx;
1519 wr_ctx->wr_curr_bio->page_count = 0;
1520 }
1521 sbio = wr_ctx->wr_curr_bio;
1522 if (sbio->page_count == 0) {
1523 struct bio *bio;
1524
1525 sbio->physical = spage->physical_for_dev_replace;
1526 sbio->logical = spage->logical;
1527 sbio->dev = wr_ctx->tgtdev;
1528 bio = sbio->bio;
1529 if (!bio) {
1530 bio = btrfs_io_bio_alloc(GFP_NOFS, wr_ctx->pages_per_wr_bio);
1531 if (!bio) {
1532 mutex_unlock(&wr_ctx->wr_lock);
1533 return -ENOMEM;
1534 }
1535 sbio->bio = bio;
1536 }
1537
1538 bio->bi_private = sbio;
1539 bio->bi_end_io = scrub_wr_bio_end_io;
1540 bio->bi_bdev = sbio->dev->bdev;
1541 bio->bi_sector = sbio->physical >> 9;
1542 sbio->err = 0;
1543 } else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
1544 spage->physical_for_dev_replace ||
1545 sbio->logical + sbio->page_count * PAGE_SIZE !=
1546 spage->logical) {
1547 scrub_wr_submit(sctx);
1548 goto again;
1549 }
1550
1551 ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0);
1552 if (ret != PAGE_SIZE) {
1553 if (sbio->page_count < 1) {
1554 bio_put(sbio->bio);
1555 sbio->bio = NULL;
1556 mutex_unlock(&wr_ctx->wr_lock);
1557 return -EIO;
1558 }
1559 scrub_wr_submit(sctx);
1560 goto again;
1561 }
1562
1563 sbio->pagev[sbio->page_count] = spage;
1564 scrub_page_get(spage);
1565 sbio->page_count++;
1566 if (sbio->page_count == wr_ctx->pages_per_wr_bio)
1567 scrub_wr_submit(sctx);
1568 mutex_unlock(&wr_ctx->wr_lock);
1569
1570 return 0;
1571 }
1572
1573 static void scrub_wr_submit(struct scrub_ctx *sctx)
1574 {
1575 struct scrub_wr_ctx *wr_ctx = &sctx->wr_ctx;
1576 struct scrub_bio *sbio;
1577
1578 if (!wr_ctx->wr_curr_bio)
1579 return;
1580
1581 sbio = wr_ctx->wr_curr_bio;
1582 wr_ctx->wr_curr_bio = NULL;
1583 WARN_ON(!sbio->bio->bi_bdev);
1584 scrub_pending_bio_inc(sctx);
1585 /* process all writes in a single worker thread. Then the block layer
1586 * orders the requests before sending them to the driver which
1587 * doubled the write performance on spinning disks when measured
1588 * with Linux 3.5 */
1589 btrfsic_submit_bio(WRITE, sbio->bio);
1590 }
1591
1592 static void scrub_wr_bio_end_io(struct bio *bio, int err)
1593 {
1594 struct scrub_bio *sbio = bio->bi_private;
1595 struct btrfs_fs_info *fs_info = sbio->dev->dev_root->fs_info;
1596
1597 sbio->err = err;
1598 sbio->bio = bio;
1599
1600 sbio->work.func = scrub_wr_bio_end_io_worker;
1601 btrfs_queue_worker(&fs_info->scrub_wr_completion_workers, &sbio->work);
1602 }
1603
1604 static void scrub_wr_bio_end_io_worker(struct btrfs_work *work)
1605 {
1606 struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
1607 struct scrub_ctx *sctx = sbio->sctx;
1608 int i;
1609
1610 WARN_ON(sbio->page_count > SCRUB_PAGES_PER_WR_BIO);
1611 if (sbio->err) {
1612 struct btrfs_dev_replace *dev_replace =
1613 &sbio->sctx->dev_root->fs_info->dev_replace;
1614
1615 for (i = 0; i < sbio->page_count; i++) {
1616 struct scrub_page *spage = sbio->pagev[i];
1617
1618 spage->io_error = 1;
1619 btrfs_dev_replace_stats_inc(&dev_replace->
1620 num_write_errors);
1621 }
1622 }
1623
1624 for (i = 0; i < sbio->page_count; i++)
1625 scrub_page_put(sbio->pagev[i]);
1626
1627 bio_put(sbio->bio);
1628 kfree(sbio);
1629 scrub_pending_bio_dec(sctx);
1630 }
1631
1632 static int scrub_checksum(struct scrub_block *sblock)
1633 {
1634 u64 flags;
1635 int ret;
1636
1637 WARN_ON(sblock->page_count < 1);
1638 flags = sblock->pagev[0]->flags;
1639 ret = 0;
1640 if (flags & BTRFS_EXTENT_FLAG_DATA)
1641 ret = scrub_checksum_data(sblock);
1642 else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1643 ret = scrub_checksum_tree_block(sblock);
1644 else if (flags & BTRFS_EXTENT_FLAG_SUPER)
1645 (void)scrub_checksum_super(sblock);
1646 else
1647 WARN_ON(1);
1648 if (ret)
1649 scrub_handle_errored_block(sblock);
1650
1651 return ret;
1652 }
1653
1654 static int scrub_checksum_data(struct scrub_block *sblock)
1655 {
1656 struct scrub_ctx *sctx = sblock->sctx;
1657 u8 csum[BTRFS_CSUM_SIZE];
1658 u8 *on_disk_csum;
1659 struct page *page;
1660 void *buffer;
1661 u32 crc = ~(u32)0;
1662 int fail = 0;
1663 u64 len;
1664 int index;
1665
1666 BUG_ON(sblock->page_count < 1);
1667 if (!sblock->pagev[0]->have_csum)
1668 return 0;
1669
1670 on_disk_csum = sblock->pagev[0]->csum;
1671 page = sblock->pagev[0]->page;
1672 buffer = kmap_atomic(page);
1673
1674 len = sctx->sectorsize;
1675 index = 0;
1676 for (;;) {
1677 u64 l = min_t(u64, len, PAGE_SIZE);
1678
1679 crc = btrfs_csum_data(buffer, crc, l);
1680 kunmap_atomic(buffer);
1681 len -= l;
1682 if (len == 0)
1683 break;
1684 index++;
1685 BUG_ON(index >= sblock->page_count);
1686 BUG_ON(!sblock->pagev[index]->page);
1687 page = sblock->pagev[index]->page;
1688 buffer = kmap_atomic(page);
1689 }
1690
1691 btrfs_csum_final(crc, csum);
1692 if (memcmp(csum, on_disk_csum, sctx->csum_size))
1693 fail = 1;
1694
1695 return fail;
1696 }
1697
1698 static int scrub_checksum_tree_block(struct scrub_block *sblock)
1699 {
1700 struct scrub_ctx *sctx = sblock->sctx;
1701 struct btrfs_header *h;
1702 struct btrfs_root *root = sctx->dev_root;
1703 struct btrfs_fs_info *fs_info = root->fs_info;
1704 u8 calculated_csum[BTRFS_CSUM_SIZE];
1705 u8 on_disk_csum[BTRFS_CSUM_SIZE];
1706 struct page *page;
1707 void *mapped_buffer;
1708 u64 mapped_size;
1709 void *p;
1710 u32 crc = ~(u32)0;
1711 int fail = 0;
1712 int crc_fail = 0;
1713 u64 len;
1714 int index;
1715
1716 BUG_ON(sblock->page_count < 1);
1717 page = sblock->pagev[0]->page;
1718 mapped_buffer = kmap_atomic(page);
1719 h = (struct btrfs_header *)mapped_buffer;
1720 memcpy(on_disk_csum, h->csum, sctx->csum_size);
1721
1722 /*
1723 * we don't use the getter functions here, as we
1724 * a) don't have an extent buffer and
1725 * b) the page is already kmapped
1726 */
1727
1728 if (sblock->pagev[0]->logical != btrfs_stack_header_bytenr(h))
1729 ++fail;
1730
1731 if (sblock->pagev[0]->generation != btrfs_stack_header_generation(h))
1732 ++fail;
1733
1734 if (memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
1735 ++fail;
1736
1737 if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
1738 BTRFS_UUID_SIZE))
1739 ++fail;
1740
1741 WARN_ON(sctx->nodesize != sctx->leafsize);
1742 len = sctx->nodesize - BTRFS_CSUM_SIZE;
1743 mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
1744 p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
1745 index = 0;
1746 for (;;) {
1747 u64 l = min_t(u64, len, mapped_size);
1748
1749 crc = btrfs_csum_data(p, crc, l);
1750 kunmap_atomic(mapped_buffer);
1751 len -= l;
1752 if (len == 0)
1753 break;
1754 index++;
1755 BUG_ON(index >= sblock->page_count);
1756 BUG_ON(!sblock->pagev[index]->page);
1757 page = sblock->pagev[index]->page;
1758 mapped_buffer = kmap_atomic(page);
1759 mapped_size = PAGE_SIZE;
1760 p = mapped_buffer;
1761 }
1762
1763 btrfs_csum_final(crc, calculated_csum);
1764 if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size))
1765 ++crc_fail;
1766
1767 return fail || crc_fail;
1768 }
1769
1770 static int scrub_checksum_super(struct scrub_block *sblock)
1771 {
1772 struct btrfs_super_block *s;
1773 struct scrub_ctx *sctx = sblock->sctx;
1774 struct btrfs_root *root = sctx->dev_root;
1775 struct btrfs_fs_info *fs_info = root->fs_info;
1776 u8 calculated_csum[BTRFS_CSUM_SIZE];
1777 u8 on_disk_csum[BTRFS_CSUM_SIZE];
1778 struct page *page;
1779 void *mapped_buffer;
1780 u64 mapped_size;
1781 void *p;
1782 u32 crc = ~(u32)0;
1783 int fail_gen = 0;
1784 int fail_cor = 0;
1785 u64 len;
1786 int index;
1787
1788 BUG_ON(sblock->page_count < 1);
1789 page = sblock->pagev[0]->page;
1790 mapped_buffer = kmap_atomic(page);
1791 s = (struct btrfs_super_block *)mapped_buffer;
1792 memcpy(on_disk_csum, s->csum, sctx->csum_size);
1793
1794 if (sblock->pagev[0]->logical != btrfs_super_bytenr(s))
1795 ++fail_cor;
1796
1797 if (sblock->pagev[0]->generation != btrfs_super_generation(s))
1798 ++fail_gen;
1799
1800 if (memcmp(s->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
1801 ++fail_cor;
1802
1803 len = BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE;
1804 mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
1805 p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
1806 index = 0;
1807 for (;;) {
1808 u64 l = min_t(u64, len, mapped_size);
1809
1810 crc = btrfs_csum_data(p, crc, l);
1811 kunmap_atomic(mapped_buffer);
1812 len -= l;
1813 if (len == 0)
1814 break;
1815 index++;
1816 BUG_ON(index >= sblock->page_count);
1817 BUG_ON(!sblock->pagev[index]->page);
1818 page = sblock->pagev[index]->page;
1819 mapped_buffer = kmap_atomic(page);
1820 mapped_size = PAGE_SIZE;
1821 p = mapped_buffer;
1822 }
1823
1824 btrfs_csum_final(crc, calculated_csum);
1825 if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size))
1826 ++fail_cor;
1827
1828 if (fail_cor + fail_gen) {
1829 /*
1830 * if we find an error in a super block, we just report it.
1831 * They will get written with the next transaction commit
1832 * anyway
1833 */
1834 spin_lock(&sctx->stat_lock);
1835 ++sctx->stat.super_errors;
1836 spin_unlock(&sctx->stat_lock);
1837 if (fail_cor)
1838 btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev,
1839 BTRFS_DEV_STAT_CORRUPTION_ERRS);
1840 else
1841 btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev,
1842 BTRFS_DEV_STAT_GENERATION_ERRS);
1843 }
1844
1845 return fail_cor + fail_gen;
1846 }
1847
1848 static void scrub_block_get(struct scrub_block *sblock)
1849 {
1850 atomic_inc(&sblock->ref_count);
1851 }
1852
1853 static void scrub_block_put(struct scrub_block *sblock)
1854 {
1855 if (atomic_dec_and_test(&sblock->ref_count)) {
1856 int i;
1857
1858 for (i = 0; i < sblock->page_count; i++)
1859 scrub_page_put(sblock->pagev[i]);
1860 kfree(sblock);
1861 }
1862 }
1863
1864 static void scrub_page_get(struct scrub_page *spage)
1865 {
1866 atomic_inc(&spage->ref_count);
1867 }
1868
1869 static void scrub_page_put(struct scrub_page *spage)
1870 {
1871 if (atomic_dec_and_test(&spage->ref_count)) {
1872 if (spage->page)
1873 __free_page(spage->page);
1874 kfree(spage);
1875 }
1876 }
1877
1878 static void scrub_submit(struct scrub_ctx *sctx)
1879 {
1880 struct scrub_bio *sbio;
1881
1882 if (sctx->curr == -1)
1883 return;
1884
1885 sbio = sctx->bios[sctx->curr];
1886 sctx->curr = -1;
1887 scrub_pending_bio_inc(sctx);
1888
1889 if (!sbio->bio->bi_bdev) {
1890 /*
1891 * this case should not happen. If btrfs_map_block() is
1892 * wrong, it could happen for dev-replace operations on
1893 * missing devices when no mirrors are available, but in
1894 * this case it should already fail the mount.
1895 * This case is handled correctly (but _very_ slowly).
1896 */
1897 printk_ratelimited(KERN_WARNING
1898 "btrfs: scrub_submit(bio bdev == NULL) is unexpected!\n");
1899 bio_endio(sbio->bio, -EIO);
1900 } else {
1901 btrfsic_submit_bio(READ, sbio->bio);
1902 }
1903 }
1904
1905 static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx,
1906 struct scrub_page *spage)
1907 {
1908 struct scrub_block *sblock = spage->sblock;
1909 struct scrub_bio *sbio;
1910 int ret;
1911
1912 again:
1913 /*
1914 * grab a fresh bio or wait for one to become available
1915 */
1916 while (sctx->curr == -1) {
1917 spin_lock(&sctx->list_lock);
1918 sctx->curr = sctx->first_free;
1919 if (sctx->curr != -1) {
1920 sctx->first_free = sctx->bios[sctx->curr]->next_free;
1921 sctx->bios[sctx->curr]->next_free = -1;
1922 sctx->bios[sctx->curr]->page_count = 0;
1923 spin_unlock(&sctx->list_lock);
1924 } else {
1925 spin_unlock(&sctx->list_lock);
1926 wait_event(sctx->list_wait, sctx->first_free != -1);
1927 }
1928 }
1929 sbio = sctx->bios[sctx->curr];
1930 if (sbio->page_count == 0) {
1931 struct bio *bio;
1932
1933 sbio->physical = spage->physical;
1934 sbio->logical = spage->logical;
1935 sbio->dev = spage->dev;
1936 bio = sbio->bio;
1937 if (!bio) {
1938 bio = btrfs_io_bio_alloc(GFP_NOFS, sctx->pages_per_rd_bio);
1939 if (!bio)
1940 return -ENOMEM;
1941 sbio->bio = bio;
1942 }
1943
1944 bio->bi_private = sbio;
1945 bio->bi_end_io = scrub_bio_end_io;
1946 bio->bi_bdev = sbio->dev->bdev;
1947 bio->bi_sector = sbio->physical >> 9;
1948 sbio->err = 0;
1949 } else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
1950 spage->physical ||
1951 sbio->logical + sbio->page_count * PAGE_SIZE !=
1952 spage->logical ||
1953 sbio->dev != spage->dev) {
1954 scrub_submit(sctx);
1955 goto again;
1956 }
1957
1958 sbio->pagev[sbio->page_count] = spage;
1959 ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0);
1960 if (ret != PAGE_SIZE) {
1961 if (sbio->page_count < 1) {
1962 bio_put(sbio->bio);
1963 sbio->bio = NULL;
1964 return -EIO;
1965 }
1966 scrub_submit(sctx);
1967 goto again;
1968 }
1969
1970 scrub_block_get(sblock); /* one for the page added to the bio */
1971 atomic_inc(&sblock->outstanding_pages);
1972 sbio->page_count++;
1973 if (sbio->page_count == sctx->pages_per_rd_bio)
1974 scrub_submit(sctx);
1975
1976 return 0;
1977 }
1978
1979 static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
1980 u64 physical, struct btrfs_device *dev, u64 flags,
1981 u64 gen, int mirror_num, u8 *csum, int force,
1982 u64 physical_for_dev_replace)
1983 {
1984 struct scrub_block *sblock;
1985 int index;
1986
1987 sblock = kzalloc(sizeof(*sblock), GFP_NOFS);
1988 if (!sblock) {
1989 spin_lock(&sctx->stat_lock);
1990 sctx->stat.malloc_errors++;
1991 spin_unlock(&sctx->stat_lock);
1992 return -ENOMEM;
1993 }
1994
1995 /* one ref inside this function, plus one for each page added to
1996 * a bio later on */
1997 atomic_set(&sblock->ref_count, 1);
1998 sblock->sctx = sctx;
1999 sblock->no_io_error_seen = 1;
2000
2001 for (index = 0; len > 0; index++) {
2002 struct scrub_page *spage;
2003 u64 l = min_t(u64, len, PAGE_SIZE);
2004
2005 spage = kzalloc(sizeof(*spage), GFP_NOFS);
2006 if (!spage) {
2007 leave_nomem:
2008 spin_lock(&sctx->stat_lock);
2009 sctx->stat.malloc_errors++;
2010 spin_unlock(&sctx->stat_lock);
2011 scrub_block_put(sblock);
2012 return -ENOMEM;
2013 }
2014 BUG_ON(index >= SCRUB_MAX_PAGES_PER_BLOCK);
2015 scrub_page_get(spage);
2016 sblock->pagev[index] = spage;
2017 spage->sblock = sblock;
2018 spage->dev = dev;
2019 spage->flags = flags;
2020 spage->generation = gen;
2021 spage->logical = logical;
2022 spage->physical = physical;
2023 spage->physical_for_dev_replace = physical_for_dev_replace;
2024 spage->mirror_num = mirror_num;
2025 if (csum) {
2026 spage->have_csum = 1;
2027 memcpy(spage->csum, csum, sctx->csum_size);
2028 } else {
2029 spage->have_csum = 0;
2030 }
2031 sblock->page_count++;
2032 spage->page = alloc_page(GFP_NOFS);
2033 if (!spage->page)
2034 goto leave_nomem;
2035 len -= l;
2036 logical += l;
2037 physical += l;
2038 physical_for_dev_replace += l;
2039 }
2040
2041 WARN_ON(sblock->page_count == 0);
2042 for (index = 0; index < sblock->page_count; index++) {
2043 struct scrub_page *spage = sblock->pagev[index];
2044 int ret;
2045
2046 ret = scrub_add_page_to_rd_bio(sctx, spage);
2047 if (ret) {
2048 scrub_block_put(sblock);
2049 return ret;
2050 }
2051 }
2052
2053 if (force)
2054 scrub_submit(sctx);
2055
2056 /* last one frees, either here or in bio completion for last page */
2057 scrub_block_put(sblock);
2058 return 0;
2059 }
2060
2061 static void scrub_bio_end_io(struct bio *bio, int err)
2062 {
2063 struct scrub_bio *sbio = bio->bi_private;
2064 struct btrfs_fs_info *fs_info = sbio->dev->dev_root->fs_info;
2065
2066 sbio->err = err;
2067 sbio->bio = bio;
2068
2069 btrfs_queue_worker(&fs_info->scrub_workers, &sbio->work);
2070 }
2071
2072 static void scrub_bio_end_io_worker(struct btrfs_work *work)
2073 {
2074 struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
2075 struct scrub_ctx *sctx = sbio->sctx;
2076 int i;
2077
2078 BUG_ON(sbio->page_count > SCRUB_PAGES_PER_RD_BIO);
2079 if (sbio->err) {
2080 for (i = 0; i < sbio->page_count; i++) {
2081 struct scrub_page *spage = sbio->pagev[i];
2082
2083 spage->io_error = 1;
2084 spage->sblock->no_io_error_seen = 0;
2085 }
2086 }
2087
2088 /* now complete the scrub_block items that have all pages completed */
2089 for (i = 0; i < sbio->page_count; i++) {
2090 struct scrub_page *spage = sbio->pagev[i];
2091 struct scrub_block *sblock = spage->sblock;
2092
2093 if (atomic_dec_and_test(&sblock->outstanding_pages))
2094 scrub_block_complete(sblock);
2095 scrub_block_put(sblock);
2096 }
2097
2098 bio_put(sbio->bio);
2099 sbio->bio = NULL;
2100 spin_lock(&sctx->list_lock);
2101 sbio->next_free = sctx->first_free;
2102 sctx->first_free = sbio->index;
2103 spin_unlock(&sctx->list_lock);
2104
2105 if (sctx->is_dev_replace &&
2106 atomic_read(&sctx->wr_ctx.flush_all_writes)) {
2107 mutex_lock(&sctx->wr_ctx.wr_lock);
2108 scrub_wr_submit(sctx);
2109 mutex_unlock(&sctx->wr_ctx.wr_lock);
2110 }
2111
2112 scrub_pending_bio_dec(sctx);
2113 }
2114
2115 static void scrub_block_complete(struct scrub_block *sblock)
2116 {
2117 if (!sblock->no_io_error_seen) {
2118 scrub_handle_errored_block(sblock);
2119 } else {
2120 /*
2121 * if has checksum error, write via repair mechanism in
2122 * dev replace case, otherwise write here in dev replace
2123 * case.
2124 */
2125 if (!scrub_checksum(sblock) && sblock->sctx->is_dev_replace)
2126 scrub_write_block_to_dev_replace(sblock);
2127 }
2128 }
2129
2130 static int scrub_find_csum(struct scrub_ctx *sctx, u64 logical, u64 len,
2131 u8 *csum)
2132 {
2133 struct btrfs_ordered_sum *sum = NULL;
2134 unsigned long index;
2135 unsigned long num_sectors;
2136
2137 while (!list_empty(&sctx->csum_list)) {
2138 sum = list_first_entry(&sctx->csum_list,
2139 struct btrfs_ordered_sum, list);
2140 if (sum->bytenr > logical)
2141 return 0;
2142 if (sum->bytenr + sum->len > logical)
2143 break;
2144
2145 ++sctx->stat.csum_discards;
2146 list_del(&sum->list);
2147 kfree(sum);
2148 sum = NULL;
2149 }
2150 if (!sum)
2151 return 0;
2152
2153 index = ((u32)(logical - sum->bytenr)) / sctx->sectorsize;
2154 num_sectors = sum->len / sctx->sectorsize;
2155 memcpy(csum, sum->sums + index, sctx->csum_size);
2156 if (index == num_sectors - 1) {
2157 list_del(&sum->list);
2158 kfree(sum);
2159 }
2160 return 1;
2161 }
2162
2163 /* scrub extent tries to collect up to 64 kB for each bio */
2164 static int scrub_extent(struct scrub_ctx *sctx, u64 logical, u64 len,
2165 u64 physical, struct btrfs_device *dev, u64 flags,
2166 u64 gen, int mirror_num, u64 physical_for_dev_replace)
2167 {
2168 int ret;
2169 u8 csum[BTRFS_CSUM_SIZE];
2170 u32 blocksize;
2171
2172 if (flags & BTRFS_EXTENT_FLAG_DATA) {
2173 blocksize = sctx->sectorsize;
2174 spin_lock(&sctx->stat_lock);
2175 sctx->stat.data_extents_scrubbed++;
2176 sctx->stat.data_bytes_scrubbed += len;
2177 spin_unlock(&sctx->stat_lock);
2178 } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
2179 WARN_ON(sctx->nodesize != sctx->leafsize);
2180 blocksize = sctx->nodesize;
2181 spin_lock(&sctx->stat_lock);
2182 sctx->stat.tree_extents_scrubbed++;
2183 sctx->stat.tree_bytes_scrubbed += len;
2184 spin_unlock(&sctx->stat_lock);
2185 } else {
2186 blocksize = sctx->sectorsize;
2187 WARN_ON(1);
2188 }
2189
2190 while (len) {
2191 u64 l = min_t(u64, len, blocksize);
2192 int have_csum = 0;
2193
2194 if (flags & BTRFS_EXTENT_FLAG_DATA) {
2195 /* push csums to sbio */
2196 have_csum = scrub_find_csum(sctx, logical, l, csum);
2197 if (have_csum == 0)
2198 ++sctx->stat.no_csum;
2199 if (sctx->is_dev_replace && !have_csum) {
2200 ret = copy_nocow_pages(sctx, logical, l,
2201 mirror_num,
2202 physical_for_dev_replace);
2203 goto behind_scrub_pages;
2204 }
2205 }
2206 ret = scrub_pages(sctx, logical, l, physical, dev, flags, gen,
2207 mirror_num, have_csum ? csum : NULL, 0,
2208 physical_for_dev_replace);
2209 behind_scrub_pages:
2210 if (ret)
2211 return ret;
2212 len -= l;
2213 logical += l;
2214 physical += l;
2215 physical_for_dev_replace += l;
2216 }
2217 return 0;
2218 }
2219
2220 static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
2221 struct map_lookup *map,
2222 struct btrfs_device *scrub_dev,
2223 int num, u64 base, u64 length,
2224 int is_dev_replace)
2225 {
2226 struct btrfs_path *path;
2227 struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
2228 struct btrfs_root *root = fs_info->extent_root;
2229 struct btrfs_root *csum_root = fs_info->csum_root;
2230 struct btrfs_extent_item *extent;
2231 struct blk_plug plug;
2232 u64 flags;
2233 int ret;
2234 int slot;
2235 u64 nstripes;
2236 struct extent_buffer *l;
2237 struct btrfs_key key;
2238 u64 physical;
2239 u64 logical;
2240 u64 logic_end;
2241 u64 generation;
2242 int mirror_num;
2243 struct reada_control *reada1;
2244 struct reada_control *reada2;
2245 struct btrfs_key key_start;
2246 struct btrfs_key key_end;
2247 u64 increment = map->stripe_len;
2248 u64 offset;
2249 u64 extent_logical;
2250 u64 extent_physical;
2251 u64 extent_len;
2252 struct btrfs_device *extent_dev;
2253 int extent_mirror_num;
2254 int stop_loop;
2255
2256 if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
2257 BTRFS_BLOCK_GROUP_RAID6)) {
2258 if (num >= nr_data_stripes(map)) {
2259 return 0;
2260 }
2261 }
2262
2263 nstripes = length;
2264 offset = 0;
2265 do_div(nstripes, map->stripe_len);
2266 if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
2267 offset = map->stripe_len * num;
2268 increment = map->stripe_len * map->num_stripes;
2269 mirror_num = 1;
2270 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
2271 int factor = map->num_stripes / map->sub_stripes;
2272 offset = map->stripe_len * (num / map->sub_stripes);
2273 increment = map->stripe_len * factor;
2274 mirror_num = num % map->sub_stripes + 1;
2275 } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
2276 increment = map->stripe_len;
2277 mirror_num = num % map->num_stripes + 1;
2278 } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
2279 increment = map->stripe_len;
2280 mirror_num = num % map->num_stripes + 1;
2281 } else {
2282 increment = map->stripe_len;
2283 mirror_num = 1;
2284 }
2285
2286 path = btrfs_alloc_path();
2287 if (!path)
2288 return -ENOMEM;
2289
2290 /*
2291 * work on commit root. The related disk blocks are static as
2292 * long as COW is applied. This means, it is save to rewrite
2293 * them to repair disk errors without any race conditions
2294 */
2295 path->search_commit_root = 1;
2296 path->skip_locking = 1;
2297
2298 /*
2299 * trigger the readahead for extent tree csum tree and wait for
2300 * completion. During readahead, the scrub is officially paused
2301 * to not hold off transaction commits
2302 */
2303 logical = base + offset;
2304
2305 wait_event(sctx->list_wait,
2306 atomic_read(&sctx->bios_in_flight) == 0);
2307 atomic_inc(&fs_info->scrubs_paused);
2308 wake_up(&fs_info->scrub_pause_wait);
2309
2310 /* FIXME it might be better to start readahead at commit root */
2311 key_start.objectid = logical;
2312 key_start.type = BTRFS_EXTENT_ITEM_KEY;
2313 key_start.offset = (u64)0;
2314 key_end.objectid = base + offset + nstripes * increment;
2315 key_end.type = BTRFS_METADATA_ITEM_KEY;
2316 key_end.offset = (u64)-1;
2317 reada1 = btrfs_reada_add(root, &key_start, &key_end);
2318
2319 key_start.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
2320 key_start.type = BTRFS_EXTENT_CSUM_KEY;
2321 key_start.offset = logical;
2322 key_end.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
2323 key_end.type = BTRFS_EXTENT_CSUM_KEY;
2324 key_end.offset = base + offset + nstripes * increment;
2325 reada2 = btrfs_reada_add(csum_root, &key_start, &key_end);
2326
2327 if (!IS_ERR(reada1))
2328 btrfs_reada_wait(reada1);
2329 if (!IS_ERR(reada2))
2330 btrfs_reada_wait(reada2);
2331
2332 mutex_lock(&fs_info->scrub_lock);
2333 while (atomic_read(&fs_info->scrub_pause_req)) {
2334 mutex_unlock(&fs_info->scrub_lock);
2335 wait_event(fs_info->scrub_pause_wait,
2336 atomic_read(&fs_info->scrub_pause_req) == 0);
2337 mutex_lock(&fs_info->scrub_lock);
2338 }
2339 atomic_dec(&fs_info->scrubs_paused);
2340 mutex_unlock(&fs_info->scrub_lock);
2341 wake_up(&fs_info->scrub_pause_wait);
2342
2343 /*
2344 * collect all data csums for the stripe to avoid seeking during
2345 * the scrub. This might currently (crc32) end up to be about 1MB
2346 */
2347 blk_start_plug(&plug);
2348
2349 /*
2350 * now find all extents for each stripe and scrub them
2351 */
2352 logical = base + offset;
2353 physical = map->stripes[num].physical;
2354 logic_end = logical + increment * nstripes;
2355 ret = 0;
2356 while (logical < logic_end) {
2357 /*
2358 * canceled?
2359 */
2360 if (atomic_read(&fs_info->scrub_cancel_req) ||
2361 atomic_read(&sctx->cancel_req)) {
2362 ret = -ECANCELED;
2363 goto out;
2364 }
2365 /*
2366 * check to see if we have to pause
2367 */
2368 if (atomic_read(&fs_info->scrub_pause_req)) {
2369 /* push queued extents */
2370 atomic_set(&sctx->wr_ctx.flush_all_writes, 1);
2371 scrub_submit(sctx);
2372 mutex_lock(&sctx->wr_ctx.wr_lock);
2373 scrub_wr_submit(sctx);
2374 mutex_unlock(&sctx->wr_ctx.wr_lock);
2375 wait_event(sctx->list_wait,
2376 atomic_read(&sctx->bios_in_flight) == 0);
2377 atomic_set(&sctx->wr_ctx.flush_all_writes, 0);
2378 atomic_inc(&fs_info->scrubs_paused);
2379 wake_up(&fs_info->scrub_pause_wait);
2380 mutex_lock(&fs_info->scrub_lock);
2381 while (atomic_read(&fs_info->scrub_pause_req)) {
2382 mutex_unlock(&fs_info->scrub_lock);
2383 wait_event(fs_info->scrub_pause_wait,
2384 atomic_read(&fs_info->scrub_pause_req) == 0);
2385 mutex_lock(&fs_info->scrub_lock);
2386 }
2387 atomic_dec(&fs_info->scrubs_paused);
2388 mutex_unlock(&fs_info->scrub_lock);
2389 wake_up(&fs_info->scrub_pause_wait);
2390 }
2391
2392 key.objectid = logical;
2393 key.type = BTRFS_EXTENT_ITEM_KEY;
2394 key.offset = (u64)-1;
2395
2396 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2397 if (ret < 0)
2398 goto out;
2399
2400 if (ret > 0) {
2401 ret = btrfs_previous_item(root, path, 0,
2402 BTRFS_EXTENT_ITEM_KEY);
2403 if (ret < 0)
2404 goto out;
2405 if (ret > 0) {
2406 /* there's no smaller item, so stick with the
2407 * larger one */
2408 btrfs_release_path(path);
2409 ret = btrfs_search_slot(NULL, root, &key,
2410 path, 0, 0);
2411 if (ret < 0)
2412 goto out;
2413 }
2414 }
2415
2416 stop_loop = 0;
2417 while (1) {
2418 u64 bytes;
2419
2420 l = path->nodes[0];
2421 slot = path->slots[0];
2422 if (slot >= btrfs_header_nritems(l)) {
2423 ret = btrfs_next_leaf(root, path);
2424 if (ret == 0)
2425 continue;
2426 if (ret < 0)
2427 goto out;
2428
2429 stop_loop = 1;
2430 break;
2431 }
2432 btrfs_item_key_to_cpu(l, &key, slot);
2433
2434 if (key.type == BTRFS_METADATA_ITEM_KEY)
2435 bytes = root->leafsize;
2436 else
2437 bytes = key.offset;
2438
2439 if (key.objectid + bytes <= logical)
2440 goto next;
2441
2442 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
2443 key.type != BTRFS_METADATA_ITEM_KEY)
2444 goto next;
2445
2446 if (key.objectid >= logical + map->stripe_len) {
2447 /* out of this device extent */
2448 if (key.objectid >= logic_end)
2449 stop_loop = 1;
2450 break;
2451 }
2452
2453 extent = btrfs_item_ptr(l, slot,
2454 struct btrfs_extent_item);
2455 flags = btrfs_extent_flags(l, extent);
2456 generation = btrfs_extent_generation(l, extent);
2457
2458 if (key.objectid < logical &&
2459 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) {
2460 printk(KERN_ERR
2461 "btrfs scrub: tree block %llu spanning "
2462 "stripes, ignored. logical=%llu\n",
2463 key.objectid, logical);
2464 goto next;
2465 }
2466
2467 again:
2468 extent_logical = key.objectid;
2469 extent_len = bytes;
2470
2471 /*
2472 * trim extent to this stripe
2473 */
2474 if (extent_logical < logical) {
2475 extent_len -= logical - extent_logical;
2476 extent_logical = logical;
2477 }
2478 if (extent_logical + extent_len >
2479 logical + map->stripe_len) {
2480 extent_len = logical + map->stripe_len -
2481 extent_logical;
2482 }
2483
2484 extent_physical = extent_logical - logical + physical;
2485 extent_dev = scrub_dev;
2486 extent_mirror_num = mirror_num;
2487 if (is_dev_replace)
2488 scrub_remap_extent(fs_info, extent_logical,
2489 extent_len, &extent_physical,
2490 &extent_dev,
2491 &extent_mirror_num);
2492
2493 ret = btrfs_lookup_csums_range(csum_root, logical,
2494 logical + map->stripe_len - 1,
2495 &sctx->csum_list, 1);
2496 if (ret)
2497 goto out;
2498
2499 ret = scrub_extent(sctx, extent_logical, extent_len,
2500 extent_physical, extent_dev, flags,
2501 generation, extent_mirror_num,
2502 extent_logical - logical + physical);
2503 if (ret)
2504 goto out;
2505
2506 scrub_free_csums(sctx);
2507 if (extent_logical + extent_len <
2508 key.objectid + bytes) {
2509 logical += increment;
2510 physical += map->stripe_len;
2511
2512 if (logical < key.objectid + bytes) {
2513 cond_resched();
2514 goto again;
2515 }
2516
2517 if (logical >= logic_end) {
2518 stop_loop = 1;
2519 break;
2520 }
2521 }
2522 next:
2523 path->slots[0]++;
2524 }
2525 btrfs_release_path(path);
2526 logical += increment;
2527 physical += map->stripe_len;
2528 spin_lock(&sctx->stat_lock);
2529 if (stop_loop)
2530 sctx->stat.last_physical = map->stripes[num].physical +
2531 length;
2532 else
2533 sctx->stat.last_physical = physical;
2534 spin_unlock(&sctx->stat_lock);
2535 if (stop_loop)
2536 break;
2537 }
2538 out:
2539 /* push queued extents */
2540 scrub_submit(sctx);
2541 mutex_lock(&sctx->wr_ctx.wr_lock);
2542 scrub_wr_submit(sctx);
2543 mutex_unlock(&sctx->wr_ctx.wr_lock);
2544
2545 blk_finish_plug(&plug);
2546 btrfs_free_path(path);
2547 return ret < 0 ? ret : 0;
2548 }
2549
2550 static noinline_for_stack int scrub_chunk(struct scrub_ctx *sctx,
2551 struct btrfs_device *scrub_dev,
2552 u64 chunk_tree, u64 chunk_objectid,
2553 u64 chunk_offset, u64 length,
2554 u64 dev_offset, int is_dev_replace)
2555 {
2556 struct btrfs_mapping_tree *map_tree =
2557 &sctx->dev_root->fs_info->mapping_tree;
2558 struct map_lookup *map;
2559 struct extent_map *em;
2560 int i;
2561 int ret = 0;
2562
2563 read_lock(&map_tree->map_tree.lock);
2564 em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
2565 read_unlock(&map_tree->map_tree.lock);
2566
2567 if (!em)
2568 return -EINVAL;
2569
2570 map = (struct map_lookup *)em->bdev;
2571 if (em->start != chunk_offset)
2572 goto out;
2573
2574 if (em->len < length)
2575 goto out;
2576
2577 for (i = 0; i < map->num_stripes; ++i) {
2578 if (map->stripes[i].dev->bdev == scrub_dev->bdev &&
2579 map->stripes[i].physical == dev_offset) {
2580 ret = scrub_stripe(sctx, map, scrub_dev, i,
2581 chunk_offset, length,
2582 is_dev_replace);
2583 if (ret)
2584 goto out;
2585 }
2586 }
2587 out:
2588 free_extent_map(em);
2589
2590 return ret;
2591 }
2592
2593 static noinline_for_stack
2594 int scrub_enumerate_chunks(struct scrub_ctx *sctx,
2595 struct btrfs_device *scrub_dev, u64 start, u64 end,
2596 int is_dev_replace)
2597 {
2598 struct btrfs_dev_extent *dev_extent = NULL;
2599 struct btrfs_path *path;
2600 struct btrfs_root *root = sctx->dev_root;
2601 struct btrfs_fs_info *fs_info = root->fs_info;
2602 u64 length;
2603 u64 chunk_tree;
2604 u64 chunk_objectid;
2605 u64 chunk_offset;
2606 int ret;
2607 int slot;
2608 struct extent_buffer *l;
2609 struct btrfs_key key;
2610 struct btrfs_key found_key;
2611 struct btrfs_block_group_cache *cache;
2612 struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
2613
2614 path = btrfs_alloc_path();
2615 if (!path)
2616 return -ENOMEM;
2617
2618 path->reada = 2;
2619 path->search_commit_root = 1;
2620 path->skip_locking = 1;
2621
2622 key.objectid = scrub_dev->devid;
2623 key.offset = 0ull;
2624 key.type = BTRFS_DEV_EXTENT_KEY;
2625
2626 while (1) {
2627 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2628 if (ret < 0)
2629 break;
2630 if (ret > 0) {
2631 if (path->slots[0] >=
2632 btrfs_header_nritems(path->nodes[0])) {
2633 ret = btrfs_next_leaf(root, path);
2634 if (ret)
2635 break;
2636 }
2637 }
2638
2639 l = path->nodes[0];
2640 slot = path->slots[0];
2641
2642 btrfs_item_key_to_cpu(l, &found_key, slot);
2643
2644 if (found_key.objectid != scrub_dev->devid)
2645 break;
2646
2647 if (btrfs_key_type(&found_key) != BTRFS_DEV_EXTENT_KEY)
2648 break;
2649
2650 if (found_key.offset >= end)
2651 break;
2652
2653 if (found_key.offset < key.offset)
2654 break;
2655
2656 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
2657 length = btrfs_dev_extent_length(l, dev_extent);
2658
2659 if (found_key.offset + length <= start) {
2660 key.offset = found_key.offset + length;
2661 btrfs_release_path(path);
2662 continue;
2663 }
2664
2665 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
2666 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
2667 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
2668
2669 /*
2670 * get a reference on the corresponding block group to prevent
2671 * the chunk from going away while we scrub it
2672 */
2673 cache = btrfs_lookup_block_group(fs_info, chunk_offset);
2674 if (!cache) {
2675 ret = -ENOENT;
2676 break;
2677 }
2678 dev_replace->cursor_right = found_key.offset + length;
2679 dev_replace->cursor_left = found_key.offset;
2680 dev_replace->item_needs_writeback = 1;
2681 ret = scrub_chunk(sctx, scrub_dev, chunk_tree, chunk_objectid,
2682 chunk_offset, length, found_key.offset,
2683 is_dev_replace);
2684
2685 /*
2686 * flush, submit all pending read and write bios, afterwards
2687 * wait for them.
2688 * Note that in the dev replace case, a read request causes
2689 * write requests that are submitted in the read completion
2690 * worker. Therefore in the current situation, it is required
2691 * that all write requests are flushed, so that all read and
2692 * write requests are really completed when bios_in_flight
2693 * changes to 0.
2694 */
2695 atomic_set(&sctx->wr_ctx.flush_all_writes, 1);
2696 scrub_submit(sctx);
2697 mutex_lock(&sctx->wr_ctx.wr_lock);
2698 scrub_wr_submit(sctx);
2699 mutex_unlock(&sctx->wr_ctx.wr_lock);
2700
2701 wait_event(sctx->list_wait,
2702 atomic_read(&sctx->bios_in_flight) == 0);
2703 atomic_set(&sctx->wr_ctx.flush_all_writes, 0);
2704 atomic_inc(&fs_info->scrubs_paused);
2705 wake_up(&fs_info->scrub_pause_wait);
2706 wait_event(sctx->list_wait,
2707 atomic_read(&sctx->workers_pending) == 0);
2708
2709 mutex_lock(&fs_info->scrub_lock);
2710 while (atomic_read(&fs_info->scrub_pause_req)) {
2711 mutex_unlock(&fs_info->scrub_lock);
2712 wait_event(fs_info->scrub_pause_wait,
2713 atomic_read(&fs_info->scrub_pause_req) == 0);
2714 mutex_lock(&fs_info->scrub_lock);
2715 }
2716 atomic_dec(&fs_info->scrubs_paused);
2717 mutex_unlock(&fs_info->scrub_lock);
2718 wake_up(&fs_info->scrub_pause_wait);
2719
2720 dev_replace->cursor_left = dev_replace->cursor_right;
2721 dev_replace->item_needs_writeback = 1;
2722 btrfs_put_block_group(cache);
2723 if (ret)
2724 break;
2725 if (is_dev_replace &&
2726 atomic64_read(&dev_replace->num_write_errors) > 0) {
2727 ret = -EIO;
2728 break;
2729 }
2730 if (sctx->stat.malloc_errors > 0) {
2731 ret = -ENOMEM;
2732 break;
2733 }
2734
2735 key.offset = found_key.offset + length;
2736 btrfs_release_path(path);
2737 }
2738
2739 btrfs_free_path(path);
2740
2741 /*
2742 * ret can still be 1 from search_slot or next_leaf,
2743 * that's not an error
2744 */
2745 return ret < 0 ? ret : 0;
2746 }
2747
2748 static noinline_for_stack int scrub_supers(struct scrub_ctx *sctx,
2749 struct btrfs_device *scrub_dev)
2750 {
2751 int i;
2752 u64 bytenr;
2753 u64 gen;
2754 int ret;
2755 struct btrfs_root *root = sctx->dev_root;
2756
2757 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
2758 return -EIO;
2759
2760 gen = root->fs_info->last_trans_committed;
2761
2762 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
2763 bytenr = btrfs_sb_offset(i);
2764 if (bytenr + BTRFS_SUPER_INFO_SIZE > scrub_dev->total_bytes)
2765 break;
2766
2767 ret = scrub_pages(sctx, bytenr, BTRFS_SUPER_INFO_SIZE, bytenr,
2768 scrub_dev, BTRFS_EXTENT_FLAG_SUPER, gen, i,
2769 NULL, 1, bytenr);
2770 if (ret)
2771 return ret;
2772 }
2773 wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
2774
2775 return 0;
2776 }
2777
2778 /*
2779 * get a reference count on fs_info->scrub_workers. start worker if necessary
2780 */
2781 static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info,
2782 int is_dev_replace)
2783 {
2784 int ret = 0;
2785
2786 mutex_lock(&fs_info->scrub_lock);
2787 if (fs_info->scrub_workers_refcnt == 0) {
2788 if (is_dev_replace)
2789 btrfs_init_workers(&fs_info->scrub_workers, "scrub", 1,
2790 &fs_info->generic_worker);
2791 else
2792 btrfs_init_workers(&fs_info->scrub_workers, "scrub",
2793 fs_info->thread_pool_size,
2794 &fs_info->generic_worker);
2795 fs_info->scrub_workers.idle_thresh = 4;
2796 ret = btrfs_start_workers(&fs_info->scrub_workers);
2797 if (ret)
2798 goto out;
2799 btrfs_init_workers(&fs_info->scrub_wr_completion_workers,
2800 "scrubwrc",
2801 fs_info->thread_pool_size,
2802 &fs_info->generic_worker);
2803 fs_info->scrub_wr_completion_workers.idle_thresh = 2;
2804 ret = btrfs_start_workers(
2805 &fs_info->scrub_wr_completion_workers);
2806 if (ret)
2807 goto out;
2808 btrfs_init_workers(&fs_info->scrub_nocow_workers, "scrubnc", 1,
2809 &fs_info->generic_worker);
2810 ret = btrfs_start_workers(&fs_info->scrub_nocow_workers);
2811 if (ret)
2812 goto out;
2813 }
2814 ++fs_info->scrub_workers_refcnt;
2815 out:
2816 mutex_unlock(&fs_info->scrub_lock);
2817
2818 return ret;
2819 }
2820
2821 static noinline_for_stack void scrub_workers_put(struct btrfs_fs_info *fs_info)
2822 {
2823 mutex_lock(&fs_info->scrub_lock);
2824 if (--fs_info->scrub_workers_refcnt == 0) {
2825 btrfs_stop_workers(&fs_info->scrub_workers);
2826 btrfs_stop_workers(&fs_info->scrub_wr_completion_workers);
2827 btrfs_stop_workers(&fs_info->scrub_nocow_workers);
2828 }
2829 WARN_ON(fs_info->scrub_workers_refcnt < 0);
2830 mutex_unlock(&fs_info->scrub_lock);
2831 }
2832
2833 int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
2834 u64 end, struct btrfs_scrub_progress *progress,
2835 int readonly, int is_dev_replace)
2836 {
2837 struct scrub_ctx *sctx;
2838 int ret;
2839 struct btrfs_device *dev;
2840
2841 if (btrfs_fs_closing(fs_info))
2842 return -EINVAL;
2843
2844 /*
2845 * check some assumptions
2846 */
2847 if (fs_info->chunk_root->nodesize != fs_info->chunk_root->leafsize) {
2848 printk(KERN_ERR
2849 "btrfs_scrub: size assumption nodesize == leafsize (%d == %d) fails\n",
2850 fs_info->chunk_root->nodesize,
2851 fs_info->chunk_root->leafsize);
2852 return -EINVAL;
2853 }
2854
2855 if (fs_info->chunk_root->nodesize > BTRFS_STRIPE_LEN) {
2856 /*
2857 * in this case scrub is unable to calculate the checksum
2858 * the way scrub is implemented. Do not handle this
2859 * situation at all because it won't ever happen.
2860 */
2861 printk(KERN_ERR
2862 "btrfs_scrub: size assumption nodesize <= BTRFS_STRIPE_LEN (%d <= %d) fails\n",
2863 fs_info->chunk_root->nodesize, BTRFS_STRIPE_LEN);
2864 return -EINVAL;
2865 }
2866
2867 if (fs_info->chunk_root->sectorsize != PAGE_SIZE) {
2868 /* not supported for data w/o checksums */
2869 printk(KERN_ERR
2870 "btrfs_scrub: size assumption sectorsize != PAGE_SIZE (%d != %lu) fails\n",
2871 fs_info->chunk_root->sectorsize, PAGE_SIZE);
2872 return -EINVAL;
2873 }
2874
2875 if (fs_info->chunk_root->nodesize >
2876 PAGE_SIZE * SCRUB_MAX_PAGES_PER_BLOCK ||
2877 fs_info->chunk_root->sectorsize >
2878 PAGE_SIZE * SCRUB_MAX_PAGES_PER_BLOCK) {
2879 /*
2880 * would exhaust the array bounds of pagev member in
2881 * struct scrub_block
2882 */
2883 pr_err("btrfs_scrub: size assumption nodesize and sectorsize <= SCRUB_MAX_PAGES_PER_BLOCK (%d <= %d && %d <= %d) fails\n",
2884 fs_info->chunk_root->nodesize,
2885 SCRUB_MAX_PAGES_PER_BLOCK,
2886 fs_info->chunk_root->sectorsize,
2887 SCRUB_MAX_PAGES_PER_BLOCK);
2888 return -EINVAL;
2889 }
2890
2891 ret = scrub_workers_get(fs_info, is_dev_replace);
2892 if (ret)
2893 return ret;
2894
2895 mutex_lock(&fs_info->fs_devices->device_list_mutex);
2896 dev = btrfs_find_device(fs_info, devid, NULL, NULL);
2897 if (!dev || (dev->missing && !is_dev_replace)) {
2898 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2899 scrub_workers_put(fs_info);
2900 return -ENODEV;
2901 }
2902 mutex_lock(&fs_info->scrub_lock);
2903
2904 if (!dev->in_fs_metadata || dev->is_tgtdev_for_dev_replace) {
2905 mutex_unlock(&fs_info->scrub_lock);
2906 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2907 scrub_workers_put(fs_info);
2908 return -EIO;
2909 }
2910
2911 btrfs_dev_replace_lock(&fs_info->dev_replace);
2912 if (dev->scrub_device ||
2913 (!is_dev_replace &&
2914 btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))) {
2915 btrfs_dev_replace_unlock(&fs_info->dev_replace);
2916 mutex_unlock(&fs_info->scrub_lock);
2917 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2918 scrub_workers_put(fs_info);
2919 return -EINPROGRESS;
2920 }
2921 btrfs_dev_replace_unlock(&fs_info->dev_replace);
2922 sctx = scrub_setup_ctx(dev, is_dev_replace);
2923 if (IS_ERR(sctx)) {
2924 mutex_unlock(&fs_info->scrub_lock);
2925 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2926 scrub_workers_put(fs_info);
2927 return PTR_ERR(sctx);
2928 }
2929 sctx->readonly = readonly;
2930 dev->scrub_device = sctx;
2931
2932 atomic_inc(&fs_info->scrubs_running);
2933 mutex_unlock(&fs_info->scrub_lock);
2934 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2935
2936 if (!is_dev_replace) {
2937 down_read(&fs_info->scrub_super_lock);
2938 ret = scrub_supers(sctx, dev);
2939 up_read(&fs_info->scrub_super_lock);
2940 }
2941
2942 if (!ret)
2943 ret = scrub_enumerate_chunks(sctx, dev, start, end,
2944 is_dev_replace);
2945
2946 wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
2947 atomic_dec(&fs_info->scrubs_running);
2948 wake_up(&fs_info->scrub_pause_wait);
2949
2950 wait_event(sctx->list_wait, atomic_read(&sctx->workers_pending) == 0);
2951
2952 if (progress)
2953 memcpy(progress, &sctx->stat, sizeof(*progress));
2954
2955 mutex_lock(&fs_info->scrub_lock);
2956 dev->scrub_device = NULL;
2957 mutex_unlock(&fs_info->scrub_lock);
2958
2959 scrub_free_ctx(sctx);
2960 scrub_workers_put(fs_info);
2961
2962 return ret;
2963 }
2964
2965 void btrfs_scrub_pause(struct btrfs_root *root)
2966 {
2967 struct btrfs_fs_info *fs_info = root->fs_info;
2968
2969 mutex_lock(&fs_info->scrub_lock);
2970 atomic_inc(&fs_info->scrub_pause_req);
2971 while (atomic_read(&fs_info->scrubs_paused) !=
2972 atomic_read(&fs_info->scrubs_running)) {
2973 mutex_unlock(&fs_info->scrub_lock);
2974 wait_event(fs_info->scrub_pause_wait,
2975 atomic_read(&fs_info->scrubs_paused) ==
2976 atomic_read(&fs_info->scrubs_running));
2977 mutex_lock(&fs_info->scrub_lock);
2978 }
2979 mutex_unlock(&fs_info->scrub_lock);
2980 }
2981
2982 void btrfs_scrub_continue(struct btrfs_root *root)
2983 {
2984 struct btrfs_fs_info *fs_info = root->fs_info;
2985
2986 atomic_dec(&fs_info->scrub_pause_req);
2987 wake_up(&fs_info->scrub_pause_wait);
2988 }
2989
2990 void btrfs_scrub_pause_super(struct btrfs_root *root)
2991 {
2992 down_write(&root->fs_info->scrub_super_lock);
2993 }
2994
2995 void btrfs_scrub_continue_super(struct btrfs_root *root)
2996 {
2997 up_write(&root->fs_info->scrub_super_lock);
2998 }
2999
3000 int btrfs_scrub_cancel(struct btrfs_fs_info *fs_info)
3001 {
3002 mutex_lock(&fs_info->scrub_lock);
3003 if (!atomic_read(&fs_info->scrubs_running)) {
3004 mutex_unlock(&fs_info->scrub_lock);
3005 return -ENOTCONN;
3006 }
3007
3008 atomic_inc(&fs_info->scrub_cancel_req);
3009 while (atomic_read(&fs_info->scrubs_running)) {
3010 mutex_unlock(&fs_info->scrub_lock);
3011 wait_event(fs_info->scrub_pause_wait,
3012 atomic_read(&fs_info->scrubs_running) == 0);
3013 mutex_lock(&fs_info->scrub_lock);
3014 }
3015 atomic_dec(&fs_info->scrub_cancel_req);
3016 mutex_unlock(&fs_info->scrub_lock);
3017
3018 return 0;
3019 }
3020
3021 int btrfs_scrub_cancel_dev(struct btrfs_fs_info *fs_info,
3022 struct btrfs_device *dev)
3023 {
3024 struct scrub_ctx *sctx;
3025
3026 mutex_lock(&fs_info->scrub_lock);
3027 sctx = dev->scrub_device;
3028 if (!sctx) {
3029 mutex_unlock(&fs_info->scrub_lock);
3030 return -ENOTCONN;
3031 }
3032 atomic_inc(&sctx->cancel_req);
3033 while (dev->scrub_device) {
3034 mutex_unlock(&fs_info->scrub_lock);
3035 wait_event(fs_info->scrub_pause_wait,
3036 dev->scrub_device == NULL);
3037 mutex_lock(&fs_info->scrub_lock);
3038 }
3039 mutex_unlock(&fs_info->scrub_lock);
3040
3041 return 0;
3042 }
3043
3044 int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
3045 struct btrfs_scrub_progress *progress)
3046 {
3047 struct btrfs_device *dev;
3048 struct scrub_ctx *sctx = NULL;
3049
3050 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
3051 dev = btrfs_find_device(root->fs_info, devid, NULL, NULL);
3052 if (dev)
3053 sctx = dev->scrub_device;
3054 if (sctx)
3055 memcpy(progress, &sctx->stat, sizeof(*progress));
3056 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
3057
3058 return dev ? (sctx ? 0 : -ENOTCONN) : -ENODEV;
3059 }
3060
3061 static void scrub_remap_extent(struct btrfs_fs_info *fs_info,
3062 u64 extent_logical, u64 extent_len,
3063 u64 *extent_physical,
3064 struct btrfs_device **extent_dev,
3065 int *extent_mirror_num)
3066 {
3067 u64 mapped_length;
3068 struct btrfs_bio *bbio = NULL;
3069 int ret;
3070
3071 mapped_length = extent_len;
3072 ret = btrfs_map_block(fs_info, READ, extent_logical,
3073 &mapped_length, &bbio, 0);
3074 if (ret || !bbio || mapped_length < extent_len ||
3075 !bbio->stripes[0].dev->bdev) {
3076 kfree(bbio);
3077 return;
3078 }
3079
3080 *extent_physical = bbio->stripes[0].physical;
3081 *extent_mirror_num = bbio->mirror_num;
3082 *extent_dev = bbio->stripes[0].dev;
3083 kfree(bbio);
3084 }
3085
3086 static int scrub_setup_wr_ctx(struct scrub_ctx *sctx,
3087 struct scrub_wr_ctx *wr_ctx,
3088 struct btrfs_fs_info *fs_info,
3089 struct btrfs_device *dev,
3090 int is_dev_replace)
3091 {
3092 WARN_ON(wr_ctx->wr_curr_bio != NULL);
3093
3094 mutex_init(&wr_ctx->wr_lock);
3095 wr_ctx->wr_curr_bio = NULL;
3096 if (!is_dev_replace)
3097 return 0;
3098
3099 WARN_ON(!dev->bdev);
3100 wr_ctx->pages_per_wr_bio = min_t(int, SCRUB_PAGES_PER_WR_BIO,
3101 bio_get_nr_vecs(dev->bdev));
3102 wr_ctx->tgtdev = dev;
3103 atomic_set(&wr_ctx->flush_all_writes, 0);
3104 return 0;
3105 }
3106
3107 static void scrub_free_wr_ctx(struct scrub_wr_ctx *wr_ctx)
3108 {
3109 mutex_lock(&wr_ctx->wr_lock);
3110 kfree(wr_ctx->wr_curr_bio);
3111 wr_ctx->wr_curr_bio = NULL;
3112 mutex_unlock(&wr_ctx->wr_lock);
3113 }
3114
3115 static int copy_nocow_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
3116 int mirror_num, u64 physical_for_dev_replace)
3117 {
3118 struct scrub_copy_nocow_ctx *nocow_ctx;
3119 struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
3120
3121 nocow_ctx = kzalloc(sizeof(*nocow_ctx), GFP_NOFS);
3122 if (!nocow_ctx) {
3123 spin_lock(&sctx->stat_lock);
3124 sctx->stat.malloc_errors++;
3125 spin_unlock(&sctx->stat_lock);
3126 return -ENOMEM;
3127 }
3128
3129 scrub_pending_trans_workers_inc(sctx);
3130
3131 nocow_ctx->sctx = sctx;
3132 nocow_ctx->logical = logical;
3133 nocow_ctx->len = len;
3134 nocow_ctx->mirror_num = mirror_num;
3135 nocow_ctx->physical_for_dev_replace = physical_for_dev_replace;
3136 nocow_ctx->work.func = copy_nocow_pages_worker;
3137 INIT_LIST_HEAD(&nocow_ctx->inodes);
3138 btrfs_queue_worker(&fs_info->scrub_nocow_workers,
3139 &nocow_ctx->work);
3140
3141 return 0;
3142 }
3143
3144 static int record_inode_for_nocow(u64 inum, u64 offset, u64 root, void *ctx)
3145 {
3146 struct scrub_copy_nocow_ctx *nocow_ctx = ctx;
3147 struct scrub_nocow_inode *nocow_inode;
3148
3149 nocow_inode = kzalloc(sizeof(*nocow_inode), GFP_NOFS);
3150 if (!nocow_inode)
3151 return -ENOMEM;
3152 nocow_inode->inum = inum;
3153 nocow_inode->offset = offset;
3154 nocow_inode->root = root;
3155 list_add_tail(&nocow_inode->list, &nocow_ctx->inodes);
3156 return 0;
3157 }
3158
3159 #define COPY_COMPLETE 1
3160
3161 static void copy_nocow_pages_worker(struct btrfs_work *work)
3162 {
3163 struct scrub_copy_nocow_ctx *nocow_ctx =
3164 container_of(work, struct scrub_copy_nocow_ctx, work);
3165 struct scrub_ctx *sctx = nocow_ctx->sctx;
3166 u64 logical = nocow_ctx->logical;
3167 u64 len = nocow_ctx->len;
3168 int mirror_num = nocow_ctx->mirror_num;
3169 u64 physical_for_dev_replace = nocow_ctx->physical_for_dev_replace;
3170 int ret;
3171 struct btrfs_trans_handle *trans = NULL;
3172 struct btrfs_fs_info *fs_info;
3173 struct btrfs_path *path;
3174 struct btrfs_root *root;
3175 int not_written = 0;
3176
3177 fs_info = sctx->dev_root->fs_info;
3178 root = fs_info->extent_root;
3179
3180 path = btrfs_alloc_path();
3181 if (!path) {
3182 spin_lock(&sctx->stat_lock);
3183 sctx->stat.malloc_errors++;
3184 spin_unlock(&sctx->stat_lock);
3185 not_written = 1;
3186 goto out;
3187 }
3188
3189 trans = btrfs_join_transaction(root);
3190 if (IS_ERR(trans)) {
3191 not_written = 1;
3192 goto out;
3193 }
3194
3195 ret = iterate_inodes_from_logical(logical, fs_info, path,
3196 record_inode_for_nocow, nocow_ctx);
3197 if (ret != 0 && ret != -ENOENT) {
3198 pr_warn("iterate_inodes_from_logical() failed: log %llu, phys %llu, len %llu, mir %u, ret %d\n",
3199 logical, physical_for_dev_replace, len, mirror_num,
3200 ret);
3201 not_written = 1;
3202 goto out;
3203 }
3204
3205 btrfs_end_transaction(trans, root);
3206 trans = NULL;
3207 while (!list_empty(&nocow_ctx->inodes)) {
3208 struct scrub_nocow_inode *entry;
3209 entry = list_first_entry(&nocow_ctx->inodes,
3210 struct scrub_nocow_inode,
3211 list);
3212 list_del_init(&entry->list);
3213 ret = copy_nocow_pages_for_inode(entry->inum, entry->offset,
3214 entry->root, nocow_ctx);
3215 kfree(entry);
3216 if (ret == COPY_COMPLETE) {
3217 ret = 0;
3218 break;
3219 } else if (ret) {
3220 break;
3221 }
3222 }
3223 out:
3224 while (!list_empty(&nocow_ctx->inodes)) {
3225 struct scrub_nocow_inode *entry;
3226 entry = list_first_entry(&nocow_ctx->inodes,
3227 struct scrub_nocow_inode,
3228 list);
3229 list_del_init(&entry->list);
3230 kfree(entry);
3231 }
3232 if (trans && !IS_ERR(trans))
3233 btrfs_end_transaction(trans, root);
3234 if (not_written)
3235 btrfs_dev_replace_stats_inc(&fs_info->dev_replace.
3236 num_uncorrectable_read_errors);
3237
3238 btrfs_free_path(path);
3239 kfree(nocow_ctx);
3240
3241 scrub_pending_trans_workers_dec(sctx);
3242 }
3243
3244 static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root,
3245 struct scrub_copy_nocow_ctx *nocow_ctx)
3246 {
3247 struct btrfs_fs_info *fs_info = nocow_ctx->sctx->dev_root->fs_info;
3248 struct btrfs_key key;
3249 struct inode *inode;
3250 struct page *page;
3251 struct btrfs_root *local_root;
3252 struct btrfs_ordered_extent *ordered;
3253 struct extent_map *em;
3254 struct extent_state *cached_state = NULL;
3255 struct extent_io_tree *io_tree;
3256 u64 physical_for_dev_replace;
3257 u64 len = nocow_ctx->len;
3258 u64 lockstart = offset, lockend = offset + len - 1;
3259 unsigned long index;
3260 int srcu_index;
3261 int ret = 0;
3262 int err = 0;
3263
3264 key.objectid = root;
3265 key.type = BTRFS_ROOT_ITEM_KEY;
3266 key.offset = (u64)-1;
3267
3268 srcu_index = srcu_read_lock(&fs_info->subvol_srcu);
3269
3270 local_root = btrfs_read_fs_root_no_name(fs_info, &key);
3271 if (IS_ERR(local_root)) {
3272 srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
3273 return PTR_ERR(local_root);
3274 }
3275
3276 key.type = BTRFS_INODE_ITEM_KEY;
3277 key.objectid = inum;
3278 key.offset = 0;
3279 inode = btrfs_iget(fs_info->sb, &key, local_root, NULL);
3280 srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
3281 if (IS_ERR(inode))
3282 return PTR_ERR(inode);
3283
3284 /* Avoid truncate/dio/punch hole.. */
3285 mutex_lock(&inode->i_mutex);
3286 inode_dio_wait(inode);
3287
3288 physical_for_dev_replace = nocow_ctx->physical_for_dev_replace;
3289 io_tree = &BTRFS_I(inode)->io_tree;
3290
3291 lock_extent_bits(io_tree, lockstart, lockend, 0, &cached_state);
3292 ordered = btrfs_lookup_ordered_range(inode, lockstart, len);
3293 if (ordered) {
3294 btrfs_put_ordered_extent(ordered);
3295 goto out_unlock;
3296 }
3297
3298 em = btrfs_get_extent(inode, NULL, 0, lockstart, len, 0);
3299 if (IS_ERR(em)) {
3300 ret = PTR_ERR(em);
3301 goto out_unlock;
3302 }
3303
3304 /*
3305 * This extent does not actually cover the logical extent anymore,
3306 * move on to the next inode.
3307 */
3308 if (em->block_start > nocow_ctx->logical ||
3309 em->block_start + em->block_len < nocow_ctx->logical + len) {
3310 free_extent_map(em);
3311 goto out_unlock;
3312 }
3313 free_extent_map(em);
3314
3315 while (len >= PAGE_CACHE_SIZE) {
3316 index = offset >> PAGE_CACHE_SHIFT;
3317 again:
3318 page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
3319 if (!page) {
3320 pr_err("find_or_create_page() failed\n");
3321 ret = -ENOMEM;
3322 goto out;
3323 }
3324
3325 if (PageUptodate(page)) {
3326 if (PageDirty(page))
3327 goto next_page;
3328 } else {
3329 ClearPageError(page);
3330 err = extent_read_full_page_nolock(io_tree, page,
3331 btrfs_get_extent,
3332 nocow_ctx->mirror_num);
3333 if (err) {
3334 ret = err;
3335 goto next_page;
3336 }
3337
3338 lock_page(page);
3339 /*
3340 * If the page has been remove from the page cache,
3341 * the data on it is meaningless, because it may be
3342 * old one, the new data may be written into the new
3343 * page in the page cache.
3344 */
3345 if (page->mapping != inode->i_mapping) {
3346 unlock_page(page);
3347 page_cache_release(page);
3348 goto again;
3349 }
3350 if (!PageUptodate(page)) {
3351 ret = -EIO;
3352 goto next_page;
3353 }
3354 }
3355 err = write_page_nocow(nocow_ctx->sctx,
3356 physical_for_dev_replace, page);
3357 if (err)
3358 ret = err;
3359 next_page:
3360 unlock_page(page);
3361 page_cache_release(page);
3362
3363 if (ret)
3364 break;
3365
3366 offset += PAGE_CACHE_SIZE;
3367 physical_for_dev_replace += PAGE_CACHE_SIZE;
3368 len -= PAGE_CACHE_SIZE;
3369 }
3370 ret = COPY_COMPLETE;
3371 out_unlock:
3372 unlock_extent_cached(io_tree, lockstart, lockend, &cached_state,
3373 GFP_NOFS);
3374 out:
3375 mutex_unlock(&inode->i_mutex);
3376 iput(inode);
3377 return ret;
3378 }
3379
3380 static int write_page_nocow(struct scrub_ctx *sctx,
3381 u64 physical_for_dev_replace, struct page *page)
3382 {
3383 struct bio *bio;
3384 struct btrfs_device *dev;
3385 int ret;
3386 DECLARE_COMPLETION_ONSTACK(compl);
3387
3388 dev = sctx->wr_ctx.tgtdev;
3389 if (!dev)
3390 return -EIO;
3391 if (!dev->bdev) {
3392 printk_ratelimited(KERN_WARNING
3393 "btrfs: scrub write_page_nocow(bdev == NULL) is unexpected!\n");
3394 return -EIO;
3395 }
3396 bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
3397 if (!bio) {
3398 spin_lock(&sctx->stat_lock);
3399 sctx->stat.malloc_errors++;
3400 spin_unlock(&sctx->stat_lock);
3401 return -ENOMEM;
3402 }
3403 bio->bi_private = &compl;
3404 bio->bi_end_io = scrub_complete_bio_end_io;
3405 bio->bi_size = 0;
3406 bio->bi_sector = physical_for_dev_replace >> 9;
3407 bio->bi_bdev = dev->bdev;
3408 ret = bio_add_page(bio, page, PAGE_CACHE_SIZE, 0);
3409 if (ret != PAGE_CACHE_SIZE) {
3410 leave_with_eio:
3411 bio_put(bio);
3412 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
3413 return -EIO;
3414 }
3415 btrfsic_submit_bio(WRITE_SYNC, bio);
3416 wait_for_completion(&compl);
3417
3418 if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
3419 goto leave_with_eio;
3420
3421 bio_put(bio);
3422 return 0;
3423 }
Linux with added FPC-III support