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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) STRATO AG 2012. All rights reserved.
4 */
5
6#include <linux/sched.h>
7#include <linux/bio.h>
8#include <linux/slab.h>
9#include <linux/blkdev.h>
10#include <linux/kthread.h>
11#include <linux/math64.h>
12#include "misc.h"
13#include "ctree.h"
14#include "disk-io.h"
15#include "transaction.h"
16#include "volumes.h"
17#include "async-thread.h"
18#include "dev-replace.h"
19#include "sysfs.h"
20#include "zoned.h"
21#include "block-group.h"
22#include "fs.h"
23#include "accessors.h"
24#include "scrub.h"
25
26/*
27 * Device replace overview
28 *
29 * [Objective]
30 * To copy all extents (both new and on-disk) from source device to target
31 * device, while still keeping the filesystem read-write.
32 *
33 * [Method]
34 * There are two main methods involved:
35 *
36 * - Write duplication
37 *
38 * All new writes will be written to both target and source devices, so even
39 * if replace gets canceled, sources device still contains up-to-date data.
40 *
41 * Location: handle_ops_on_dev_replace() from btrfs_map_block()
42 * Start: btrfs_dev_replace_start()
43 * End: btrfs_dev_replace_finishing()
44 * Content: Latest data/metadata
45 *
46 * - Copy existing extents
47 *
48 * This happens by reusing scrub facility, as scrub also iterates through
49 * existing extents from commit root.
50 *
51 * Location: scrub_write_block_to_dev_replace() from
52 * scrub_block_complete()
53 * Content: Data/meta from commit root.
54 *
55 * Due to the content difference, we need to avoid nocow write when dev-replace
56 * is happening. This is done by marking the block group read-only and waiting
57 * for NOCOW writes.
58 *
59 * After replace is done, the finishing part is done by swapping the target and
60 * source devices.
61 *
62 * Location: btrfs_dev_replace_update_device_in_mapping_tree() from
63 * btrfs_dev_replace_finishing()
64 */
65
66static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
67 int scrub_ret);
68static int btrfs_dev_replace_kthread(void *data);
69
70int btrfs_init_dev_replace(struct btrfs_fs_info *fs_info)
71{
72 struct btrfs_dev_lookup_args args = { .devid = BTRFS_DEV_REPLACE_DEVID };
73 struct btrfs_key key;
74 struct btrfs_root *dev_root = fs_info->dev_root;
75 struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
76 struct extent_buffer *eb;
77 int slot;
78 int ret = 0;
79 BTRFS_PATH_AUTO_FREE(path);
80 int item_size;
81 struct btrfs_dev_replace_item *ptr;
82 u64 src_devid;
83
84 if (!dev_root)
85 return 0;
86
87 path = btrfs_alloc_path();
88 if (!path)
89 return -ENOMEM;
90
91 key.objectid = 0;
92 key.type = BTRFS_DEV_REPLACE_KEY;
93 key.offset = 0;
94 ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
95 if (ret) {
96no_valid_dev_replace_entry_found:
97 /*
98 * We don't have a replace item or it's corrupted. If there is
99 * a replace target, fail the mount.
100 */
101 if (unlikely(btrfs_find_device(fs_info->fs_devices, &args))) {
102 btrfs_err(fs_info,
103 "found replace target device without a valid replace item");
104 return -EUCLEAN;
105 }
106 dev_replace->replace_state =
107 BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED;
108 dev_replace->cont_reading_from_srcdev_mode =
109 BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_ALWAYS;
110 dev_replace->time_started = 0;
111 dev_replace->time_stopped = 0;
112 atomic64_set(&dev_replace->num_write_errors, 0);
113 atomic64_set(&dev_replace->num_uncorrectable_read_errors, 0);
114 dev_replace->cursor_left = 0;
115 dev_replace->committed_cursor_left = 0;
116 dev_replace->cursor_left_last_write_of_item = 0;
117 dev_replace->cursor_right = 0;
118 dev_replace->srcdev = NULL;
119 dev_replace->tgtdev = NULL;
120 dev_replace->is_valid = 0;
121 dev_replace->item_needs_writeback = 0;
122 return 0;
123 }
124 slot = path->slots[0];
125 eb = path->nodes[0];
126 item_size = btrfs_item_size(eb, slot);
127 ptr = btrfs_item_ptr(eb, slot, struct btrfs_dev_replace_item);
128
129 if (item_size != sizeof(struct btrfs_dev_replace_item)) {
130 btrfs_warn(fs_info,
131 "dev_replace entry found has unexpected size, ignore entry");
132 goto no_valid_dev_replace_entry_found;
133 }
134
135 src_devid = btrfs_dev_replace_src_devid(eb, ptr);
136 dev_replace->cont_reading_from_srcdev_mode =
137 btrfs_dev_replace_cont_reading_from_srcdev_mode(eb, ptr);
138 dev_replace->replace_state = btrfs_dev_replace_replace_state(eb, ptr);
139 dev_replace->time_started = btrfs_dev_replace_time_started(eb, ptr);
140 dev_replace->time_stopped =
141 btrfs_dev_replace_time_stopped(eb, ptr);
142 atomic64_set(&dev_replace->num_write_errors,
143 btrfs_dev_replace_num_write_errors(eb, ptr));
144 atomic64_set(&dev_replace->num_uncorrectable_read_errors,
145 btrfs_dev_replace_num_uncorrectable_read_errors(eb, ptr));
146 dev_replace->cursor_left = btrfs_dev_replace_cursor_left(eb, ptr);
147 dev_replace->committed_cursor_left = dev_replace->cursor_left;
148 dev_replace->cursor_left_last_write_of_item = dev_replace->cursor_left;
149 dev_replace->cursor_right = btrfs_dev_replace_cursor_right(eb, ptr);
150 dev_replace->is_valid = 1;
151
152 dev_replace->item_needs_writeback = 0;
153 switch (dev_replace->replace_state) {
154 case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
155 case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
156 case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
157 /*
158 * We don't have an active replace item but if there is a
159 * replace target, fail the mount.
160 */
161 if (unlikely(btrfs_find_device(fs_info->fs_devices, &args))) {
162 btrfs_err(fs_info,
163"replace without active item, run 'device scan --forget' on the target device");
164 ret = -EUCLEAN;
165 } else {
166 dev_replace->srcdev = NULL;
167 dev_replace->tgtdev = NULL;
168 }
169 break;
170 case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
171 case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
172 dev_replace->tgtdev = btrfs_find_device(fs_info->fs_devices, &args);
173 args.devid = src_devid;
174 dev_replace->srcdev = btrfs_find_device(fs_info->fs_devices, &args);
175
176 /*
177 * allow 'btrfs dev replace_cancel' if src/tgt device is
178 * missing
179 */
180 if (unlikely(!dev_replace->srcdev && !btrfs_test_opt(fs_info, DEGRADED))) {
181 ret = -EIO;
182 btrfs_warn(fs_info,
183 "cannot mount because device replace operation is ongoing and");
184 btrfs_warn(fs_info,
185 "srcdev (devid %llu) is missing, need to run 'btrfs dev scan'?",
186 src_devid);
187 }
188 if (unlikely(!dev_replace->tgtdev && !btrfs_test_opt(fs_info, DEGRADED))) {
189 ret = -EIO;
190 btrfs_warn(fs_info,
191 "cannot mount because device replace operation is ongoing and");
192 btrfs_warn(fs_info,
193 "tgtdev (devid %llu) is missing, need to run 'btrfs dev scan'?",
194 BTRFS_DEV_REPLACE_DEVID);
195 }
196 if (dev_replace->tgtdev) {
197 if (dev_replace->srcdev) {
198 dev_replace->tgtdev->total_bytes =
199 dev_replace->srcdev->total_bytes;
200 dev_replace->tgtdev->disk_total_bytes =
201 dev_replace->srcdev->disk_total_bytes;
202 dev_replace->tgtdev->commit_total_bytes =
203 dev_replace->srcdev->commit_total_bytes;
204 dev_replace->tgtdev->bytes_used =
205 dev_replace->srcdev->bytes_used;
206 dev_replace->tgtdev->commit_bytes_used =
207 dev_replace->srcdev->commit_bytes_used;
208 }
209 set_bit(BTRFS_DEV_STATE_REPLACE_TGT,
210 &dev_replace->tgtdev->dev_state);
211
212 WARN_ON(fs_info->fs_devices->rw_devices == 0);
213 dev_replace->tgtdev->io_width = fs_info->sectorsize;
214 dev_replace->tgtdev->io_align = fs_info->sectorsize;
215 dev_replace->tgtdev->sector_size = fs_info->sectorsize;
216 dev_replace->tgtdev->fs_info = fs_info;
217 set_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
218 &dev_replace->tgtdev->dev_state);
219 }
220 break;
221 }
222
223 return ret;
224}
225
226/*
227 * Initialize a new device for device replace target from a given source dev
228 * and path.
229 *
230 * Return 0 and new device in @device_out, otherwise return < 0
231 */
232static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
233 const char *device_path,
234 struct btrfs_device *srcdev,
235 struct btrfs_device **device_out)
236{
237 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
238 struct btrfs_device *device = NULL;
239 struct btrfs_device *tmp_device;
240 struct file *bdev_file;
241 struct block_device *bdev;
242 u64 devid = BTRFS_DEV_REPLACE_DEVID;
243 int ret = 0;
244
245 *device_out = NULL;
246 if (srcdev->fs_devices->seeding) {
247 btrfs_err(fs_info, "the filesystem is a seed filesystem!");
248 return -EINVAL;
249 }
250
251 /* Unfreezable for the whole replace; see btrfs_dev_replace_start(). */
252 bdev_file = btrfs_open_device_deny_freeze(device_path, fs_info->sb);
253 if (IS_ERR(bdev_file)) {
254 btrfs_err(fs_info, "target device %s is invalid!", device_path);
255 return PTR_ERR(bdev_file);
256 }
257 bdev = file_bdev(bdev_file);
258
259 if (!btrfs_check_device_zone_type(fs_info, bdev)) {
260 btrfs_err(fs_info,
261 "dev-replace: zoned type of target device mismatch with filesystem");
262 ret = -EINVAL;
263 goto error;
264 }
265
266 sync_blockdev(bdev);
267
268 list_for_each_entry(tmp_device, &fs_devices->devices, dev_list) {
269 if (tmp_device->bdev == bdev) {
270 btrfs_err(fs_info,
271 "target device is in the filesystem!");
272 ret = -EEXIST;
273 goto error;
274 }
275 }
276
277
278 if (bdev_nr_bytes(bdev) < btrfs_device_get_total_bytes(srcdev)) {
279 btrfs_err(fs_info,
280 "target device is smaller than source device!");
281 ret = -EINVAL;
282 goto error;
283 }
284
285
286 device = btrfs_alloc_device(NULL, &devid, NULL, device_path);
287 if (IS_ERR(device)) {
288 ret = PTR_ERR(device);
289 device = NULL;
290 goto error;
291 }
292
293 ret = lookup_bdev(device_path, &device->devt);
294 if (ret)
295 goto error;
296
297 set_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
298 device->generation = 0;
299 device->io_width = fs_info->sectorsize;
300 device->io_align = fs_info->sectorsize;
301 device->sector_size = fs_info->sectorsize;
302 device->total_bytes = btrfs_device_get_total_bytes(srcdev);
303 device->disk_total_bytes = btrfs_device_get_disk_total_bytes(srcdev);
304 device->bytes_used = btrfs_device_get_bytes_used(srcdev);
305 device->commit_total_bytes = srcdev->commit_total_bytes;
306 device->commit_bytes_used = device->bytes_used;
307 device->fs_info = fs_info;
308 device->bdev = bdev;
309 device->bdev_file = bdev_file;
310 set_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state);
311 set_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state);
312 /* Check the comment in btrfs_init_new_device() for the reason. */
313 atomic_inc(&device->dev_stats_ccnt);
314 device->dev_stats_valid = 1;
315 set_blocksize(bdev_file, BTRFS_BDEV_BLOCKSIZE);
316 device->fs_devices = fs_devices;
317
318 ret = btrfs_get_dev_zone_info(device, false);
319 if (ret)
320 goto error;
321
322 mutex_lock(&fs_devices->device_list_mutex);
323 list_add(&device->dev_list, &fs_devices->devices);
324 fs_devices->num_devices++;
325 fs_devices->open_devices++;
326 mutex_unlock(&fs_devices->device_list_mutex);
327
328 *device_out = device;
329 return 0;
330
331error:
332 /* Undo the open-time freeze deny. */
333 if (device)
334 btrfs_free_device(device);
335 btrfs_release_device_allow_freeze(bdev_file);
336 return ret;
337}
338
339/*
340 * called from commit_transaction. Writes changed device replace state to
341 * disk.
342 */
343int btrfs_run_dev_replace(struct btrfs_trans_handle *trans)
344{
345 struct btrfs_fs_info *fs_info = trans->fs_info;
346 int ret;
347 struct btrfs_root *dev_root = fs_info->dev_root;
348 BTRFS_PATH_AUTO_FREE(path);
349 struct btrfs_key key;
350 struct extent_buffer *eb;
351 struct btrfs_dev_replace_item *ptr;
352 struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
353
354 down_read(&dev_replace->rwsem);
355 if (!dev_replace->is_valid ||
356 !dev_replace->item_needs_writeback) {
357 up_read(&dev_replace->rwsem);
358 return 0;
359 }
360 up_read(&dev_replace->rwsem);
361
362 key.objectid = 0;
363 key.type = BTRFS_DEV_REPLACE_KEY;
364 key.offset = 0;
365
366 path = btrfs_alloc_path();
367 if (!path)
368 return -ENOMEM;
369
370 ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
371 if (ret < 0) {
372 btrfs_warn(fs_info,
373 "error %d while searching for dev_replace item!",
374 ret);
375 return ret;
376 }
377
378 if (ret == 0 &&
379 btrfs_item_size(path->nodes[0], path->slots[0]) < sizeof(*ptr)) {
380 /*
381 * need to delete old one and insert a new one.
382 * Since no attempt is made to recover any old state, if the
383 * dev_replace state is 'running', the data on the target
384 * drive is lost.
385 * It would be possible to recover the state: just make sure
386 * that the beginning of the item is never changed and always
387 * contains all the essential information. Then read this
388 * minimal set of information and use it as a base for the
389 * new state.
390 */
391 ret = btrfs_del_item(trans, dev_root, path);
392 if (ret != 0) {
393 btrfs_warn(fs_info,
394 "delete too small dev_replace item failed %d!",
395 ret);
396 return ret;
397 }
398 ret = 1;
399 }
400
401 if (ret == 1) {
402 /* need to insert a new item */
403 btrfs_release_path(path);
404 ret = btrfs_insert_empty_item(trans, dev_root, path,
405 &key, sizeof(*ptr));
406 if (ret < 0) {
407 btrfs_warn(fs_info,
408 "insert dev_replace item failed %d!", ret);
409 return ret;
410 }
411 }
412
413 eb = path->nodes[0];
414 ptr = btrfs_item_ptr(eb, path->slots[0],
415 struct btrfs_dev_replace_item);
416
417 down_write(&dev_replace->rwsem);
418 if (dev_replace->srcdev)
419 btrfs_set_dev_replace_src_devid(eb, ptr,
420 dev_replace->srcdev->devid);
421 else
422 btrfs_set_dev_replace_src_devid(eb, ptr, (u64)-1);
423 btrfs_set_dev_replace_cont_reading_from_srcdev_mode(eb, ptr,
424 dev_replace->cont_reading_from_srcdev_mode);
425 btrfs_set_dev_replace_replace_state(eb, ptr,
426 dev_replace->replace_state);
427 btrfs_set_dev_replace_time_started(eb, ptr, dev_replace->time_started);
428 btrfs_set_dev_replace_time_stopped(eb, ptr, dev_replace->time_stopped);
429 btrfs_set_dev_replace_num_write_errors(eb, ptr,
430 atomic64_read(&dev_replace->num_write_errors));
431 btrfs_set_dev_replace_num_uncorrectable_read_errors(eb, ptr,
432 atomic64_read(&dev_replace->num_uncorrectable_read_errors));
433 dev_replace->cursor_left_last_write_of_item =
434 dev_replace->cursor_left;
435 btrfs_set_dev_replace_cursor_left(eb, ptr,
436 dev_replace->cursor_left_last_write_of_item);
437 btrfs_set_dev_replace_cursor_right(eb, ptr,
438 dev_replace->cursor_right);
439 dev_replace->item_needs_writeback = 0;
440 up_write(&dev_replace->rwsem);
441
442 return ret;
443}
444
445static int mark_block_group_to_copy(struct btrfs_fs_info *fs_info,
446 struct btrfs_device *src_dev)
447{
448 struct btrfs_path *path;
449 struct btrfs_key key;
450 struct btrfs_key found_key;
451 struct btrfs_root *root = fs_info->dev_root;
452 struct btrfs_dev_extent *dev_extent = NULL;
453 struct btrfs_block_group *cache;
454 struct btrfs_trans_handle *trans;
455 int iter_ret = 0;
456 int ret = 0;
457 u64 chunk_offset;
458
459 /* Do not use "to_copy" on non zoned filesystem for now */
460 if (!btrfs_is_zoned(fs_info))
461 return 0;
462
463 mutex_lock(&fs_info->chunk_mutex);
464
465 /* Ensure we don't have pending new block group */
466 spin_lock(&fs_info->trans_lock);
467 while (fs_info->running_transaction &&
468 !list_empty(&fs_info->running_transaction->dev_update_list)) {
469 spin_unlock(&fs_info->trans_lock);
470 mutex_unlock(&fs_info->chunk_mutex);
471 trans = btrfs_attach_transaction(root);
472 if (IS_ERR(trans)) {
473 ret = PTR_ERR(trans);
474 mutex_lock(&fs_info->chunk_mutex);
475 if (ret == -ENOENT) {
476 spin_lock(&fs_info->trans_lock);
477 continue;
478 } else {
479 goto unlock;
480 }
481 }
482
483 ret = btrfs_commit_transaction(trans);
484 mutex_lock(&fs_info->chunk_mutex);
485 if (ret)
486 goto unlock;
487
488 spin_lock(&fs_info->trans_lock);
489 }
490 spin_unlock(&fs_info->trans_lock);
491
492 path = btrfs_alloc_path();
493 if (!path) {
494 ret = -ENOMEM;
495 goto unlock;
496 }
497
498 path->reada = READA_FORWARD;
499 path->search_commit_root = true;
500 path->skip_locking = true;
501 path->need_commit_sem = true;
502
503 key.objectid = src_dev->devid;
504 key.type = BTRFS_DEV_EXTENT_KEY;
505 key.offset = 0;
506
507 btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) {
508 struct extent_buffer *leaf = path->nodes[0];
509
510 if (found_key.objectid != src_dev->devid)
511 break;
512
513 if (found_key.type != BTRFS_DEV_EXTENT_KEY)
514 break;
515
516 if (found_key.offset < key.offset)
517 break;
518
519 dev_extent = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_extent);
520
521 chunk_offset = btrfs_dev_extent_chunk_offset(leaf, dev_extent);
522
523 cache = btrfs_lookup_block_group(fs_info, chunk_offset);
524 if (!cache)
525 continue;
526
527 set_bit(BLOCK_GROUP_FLAG_TO_COPY, &cache->runtime_flags);
528 btrfs_put_block_group(cache);
529 }
530 if (iter_ret < 0)
531 ret = iter_ret;
532
533 btrfs_free_path(path);
534unlock:
535 mutex_unlock(&fs_info->chunk_mutex);
536
537 return ret;
538}
539
540bool btrfs_finish_block_group_to_copy(struct btrfs_device *srcdev,
541 struct btrfs_block_group *cache,
542 u64 physical)
543{
544 struct btrfs_fs_info *fs_info = cache->fs_info;
545 struct btrfs_chunk_map *map;
546 u64 chunk_offset = cache->start;
547 int num_extents, cur_extent;
548 int i;
549
550 /* Do not use "to_copy" on non zoned filesystem for now */
551 if (!btrfs_is_zoned(fs_info))
552 return true;
553
554 spin_lock(&cache->lock);
555 if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &cache->runtime_flags)) {
556 spin_unlock(&cache->lock);
557 return true;
558 }
559 spin_unlock(&cache->lock);
560
561 map = btrfs_get_chunk_map(fs_info, chunk_offset, 1);
562 ASSERT(!IS_ERR(map));
563
564 num_extents = 0;
565 cur_extent = 0;
566 for (i = 0; i < map->num_stripes; i++) {
567 /* We have more device extent to copy */
568 if (srcdev != map->stripes[i].dev)
569 continue;
570
571 num_extents++;
572 if (physical == map->stripes[i].physical)
573 cur_extent = i;
574 }
575
576 btrfs_free_chunk_map(map);
577
578 if (num_extents > 1 && cur_extent < num_extents - 1) {
579 /*
580 * Has more stripes on this device. Keep this block group
581 * readonly until we finish all the stripes.
582 */
583 return false;
584 }
585
586 /* Last stripe on this device */
587 clear_bit(BLOCK_GROUP_FLAG_TO_COPY, &cache->runtime_flags);
588
589 return true;
590}
591
592static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
593 const char *tgtdev_name, u64 srcdevid, const char *srcdev_name,
594 int read_src)
595{
596 struct btrfs_root *root = fs_info->dev_root;
597 struct btrfs_trans_handle *trans;
598 struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
599 int ret;
600 struct btrfs_device *tgt_device = NULL;
601 struct btrfs_device *src_device = NULL;
602
603 src_device = btrfs_find_device_by_devspec(fs_info, srcdevid,
604 srcdev_name);
605 if (IS_ERR(src_device))
606 return PTR_ERR(src_device);
607
608 if (btrfs_pinned_by_swapfile(fs_info, src_device)) {
609 btrfs_warn(fs_info,
610 "cannot replace device %s (devid %llu) due to active swapfile",
611 btrfs_dev_name(src_device), src_device->devid);
612 return -ETXTBSY;
613 }
614
615 /*
616 * Here we commit the transaction to make sure commit_total_bytes
617 * of all the devices are updated.
618 */
619 trans = btrfs_attach_transaction(root);
620 if (!IS_ERR(trans)) {
621 ret = btrfs_commit_transaction(trans);
622 if (ret)
623 return ret;
624 } else if (PTR_ERR(trans) != -ENOENT) {
625 return PTR_ERR(trans);
626 }
627
628 ret = btrfs_init_dev_replace_tgtdev(fs_info, tgtdev_name,
629 src_device, &tgt_device);
630 if (ret)
631 return ret;
632
633 /* Deny the source before mark, so every 'leave' unwinds both denied. */
634 if (src_device->bdev) {
635 ret = bdev_deny_freeze(src_device->bdev);
636 if (ret) {
637 btrfs_destroy_dev_replace_tgtdev(tgt_device, true);
638 return ret;
639 }
640 }
641
642 ret = mark_block_group_to_copy(fs_info, src_device);
643 if (ret)
644 goto leave;
645
646 down_write(&dev_replace->rwsem);
647 dev_replace->replace_task = current;
648 switch (dev_replace->replace_state) {
649 case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
650 case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
651 case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
652 break;
653 case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
654 case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
655 DEBUG_WARN("unexpected STARTED or SUSPENDED dev-replace state");
656 ret = BTRFS_IOCTL_DEV_REPLACE_RESULT_ALREADY_STARTED;
657 up_write(&dev_replace->rwsem);
658 goto leave;
659 }
660
661 dev_replace->cont_reading_from_srcdev_mode = read_src;
662 dev_replace->srcdev = src_device;
663 dev_replace->tgtdev = tgt_device;
664
665 btrfs_info(fs_info,
666 "dev_replace from %s (devid %llu) to %s started",
667 btrfs_dev_name(src_device),
668 src_device->devid,
669 btrfs_dev_name(tgt_device));
670
671 /*
672 * from now on, the writes to the srcdev are all duplicated to
673 * go to the tgtdev as well (refer to btrfs_map_block()).
674 */
675 dev_replace->replace_state = BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED;
676 dev_replace->time_started = ktime_get_real_seconds();
677 dev_replace->cursor_left = 0;
678 dev_replace->committed_cursor_left = 0;
679 dev_replace->cursor_left_last_write_of_item = 0;
680 dev_replace->cursor_right = 0;
681 dev_replace->is_valid = 1;
682 dev_replace->item_needs_writeback = 1;
683 atomic64_set(&dev_replace->num_write_errors, 0);
684 atomic64_set(&dev_replace->num_uncorrectable_read_errors, 0);
685 up_write(&dev_replace->rwsem);
686
687 ret = btrfs_sysfs_add_device(tgt_device);
688 if (ret)
689 btrfs_err(fs_info, "kobj add dev failed %d", ret);
690
691 btrfs_wait_ordered_roots(fs_info, U64_MAX, NULL);
692
693 /*
694 * Commit dev_replace state and reserve 1 item for it.
695 * This is crucial to ensure we won't miss copying extents for new block
696 * groups that are allocated after we started the device replace, and
697 * must be done after setting up the device replace state.
698 */
699 trans = btrfs_start_transaction(root, 1);
700 if (IS_ERR(trans)) {
701 ret = PTR_ERR(trans);
702 down_write(&dev_replace->rwsem);
703 dev_replace->replace_state =
704 BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED;
705 dev_replace->srcdev = NULL;
706 dev_replace->tgtdev = NULL;
707 up_write(&dev_replace->rwsem);
708 goto leave;
709 }
710
711 ret = btrfs_commit_transaction(trans);
712 WARN_ON(ret);
713
714 /* the disk copy procedure reuses the scrub code */
715 ret = btrfs_scrub_dev(fs_info, src_device->devid, 0,
716 btrfs_device_get_total_bytes(src_device),
717 &dev_replace->scrub_progress, false, true);
718
719 ret = btrfs_dev_replace_finishing(fs_info, ret);
720 if (ret == -EINPROGRESS)
721 ret = BTRFS_IOCTL_DEV_REPLACE_RESULT_SCRUB_INPROGRESS;
722
723 return ret;
724
725leave:
726 if (src_device->bdev)
727 bdev_allow_freeze(src_device->bdev);
728 btrfs_destroy_dev_replace_tgtdev(tgt_device, true);
729 return ret;
730}
731
732static int btrfs_check_replace_dev_names(struct btrfs_ioctl_dev_replace_args *args)
733{
734 if (args->start.srcdevid == 0) {
735 if (memchr(args->start.srcdev_name, 0,
736 sizeof(args->start.srcdev_name)) == NULL)
737 return -ENAMETOOLONG;
738 } else {
739 args->start.srcdev_name[0] = 0;
740 }
741
742 if (memchr(args->start.tgtdev_name, 0,
743 sizeof(args->start.tgtdev_name)) == NULL)
744 return -ENAMETOOLONG;
745
746 return 0;
747}
748
749int btrfs_dev_replace_by_ioctl(struct btrfs_fs_info *fs_info,
750 struct btrfs_ioctl_dev_replace_args *args)
751{
752 int ret;
753
754 switch (args->start.cont_reading_from_srcdev_mode) {
755 case BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_ALWAYS:
756 case BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_AVOID:
757 break;
758 default:
759 return -EINVAL;
760 }
761 ret = btrfs_check_replace_dev_names(args);
762 if (ret < 0)
763 return ret;
764
765 ret = btrfs_dev_replace_start(fs_info, args->start.tgtdev_name,
766 args->start.srcdevid,
767 args->start.srcdev_name,
768 args->start.cont_reading_from_srcdev_mode);
769 args->result = ret;
770 /* don't warn if EINPROGRESS, someone else might be running scrub */
771 if (ret == BTRFS_IOCTL_DEV_REPLACE_RESULT_SCRUB_INPROGRESS ||
772 ret == BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR)
773 return 0;
774
775 return ret;
776}
777
778/*
779 * blocked until all in-flight bios operations are finished.
780 */
781static void btrfs_rm_dev_replace_blocked(struct btrfs_fs_info *fs_info)
782{
783 set_bit(BTRFS_FS_STATE_DEV_REPLACING, &fs_info->fs_state);
784 wait_event(fs_info->dev_replace.replace_wait, !percpu_counter_sum(
785 &fs_info->dev_replace.bio_counter));
786}
787
788/*
789 * we have removed target device, it is safe to allow new bios request.
790 */
791static void btrfs_rm_dev_replace_unblocked(struct btrfs_fs_info *fs_info)
792{
793 clear_bit(BTRFS_FS_STATE_DEV_REPLACING, &fs_info->fs_state);
794 wake_up(&fs_info->dev_replace.replace_wait);
795}
796
797/*
798 * When finishing the device replace, before swapping the source device with the
799 * target device we must update the chunk allocation state in the target device,
800 * as it is empty because replace works by directly copying the chunks and not
801 * through the normal chunk allocation path.
802 */
803static int btrfs_set_target_alloc_state(struct btrfs_device *srcdev,
804 struct btrfs_device *tgtdev)
805{
806 struct extent_state *cached_state = NULL;
807 u64 start = 0;
808 u64 found_start;
809 u64 found_end;
810 int ret = 0;
811
812 lockdep_assert_held(&srcdev->fs_info->chunk_mutex);
813
814 while (btrfs_find_first_extent_bit(&srcdev->alloc_state, start,
815 &found_start, &found_end,
816 CHUNK_ALLOCATED, &cached_state)) {
817 ret = btrfs_set_extent_bit(&tgtdev->alloc_state, found_start,
818 found_end, CHUNK_ALLOCATED, NULL);
819 if (ret)
820 break;
821 start = found_end + 1;
822 }
823
824 btrfs_free_extent_state(cached_state);
825 return ret;
826}
827
828static void btrfs_dev_replace_update_device_in_mapping_tree(
829 struct btrfs_fs_info *fs_info,
830 struct btrfs_device *srcdev,
831 struct btrfs_device *tgtdev)
832{
833 struct rb_node *node;
834
835 /*
836 * The chunk mutex must be held so that no new chunks can be created
837 * while we are updating existing chunks. This guarantees we don't miss
838 * any new chunk that gets created for a range that falls before the
839 * range of the last chunk we processed.
840 */
841 lockdep_assert_held(&fs_info->chunk_mutex);
842
843 write_lock(&fs_info->mapping_tree_lock);
844 node = rb_first_cached(&fs_info->mapping_tree);
845 while (node) {
846 struct rb_node *next = rb_next(node);
847 struct btrfs_chunk_map *map;
848 u64 next_start;
849
850 map = rb_entry(node, struct btrfs_chunk_map, rb_node);
851 next_start = map->start + map->chunk_len;
852
853 for (int i = 0; i < map->num_stripes; i++)
854 if (srcdev == map->stripes[i].dev)
855 map->stripes[i].dev = tgtdev;
856
857 if (cond_resched_rwlock_write(&fs_info->mapping_tree_lock)) {
858 map = btrfs_find_chunk_map_nolock(fs_info, next_start, U64_MAX);
859 if (!map)
860 break;
861 node = &map->rb_node;
862 /*
863 * Drop the lookup reference since we are holding the
864 * lock in write mode and no one can remove the chunk
865 * map from the tree and drop its tree reference.
866 */
867 btrfs_free_chunk_map(map);
868 } else {
869 node = next;
870 }
871 }
872 write_unlock(&fs_info->mapping_tree_lock);
873}
874
875static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
876 int scrub_ret)
877{
878 struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
879 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
880 struct btrfs_device *tgt_device;
881 struct btrfs_device *src_device;
882 struct btrfs_root *root = fs_info->tree_root;
883 u8 uuid_tmp[BTRFS_UUID_SIZE];
884 struct btrfs_trans_handle *trans;
885 int ret = 0;
886
887 /* don't allow cancel or unmount to disturb the finishing procedure */
888 mutex_lock(&dev_replace->lock_finishing_cancel_unmount);
889
890 down_read(&dev_replace->rwsem);
891 /* was the operation canceled, or is it finished? */
892 if (dev_replace->replace_state !=
893 BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED) {
894 up_read(&dev_replace->rwsem);
895 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
896 return 0;
897 }
898
899 tgt_device = dev_replace->tgtdev;
900 src_device = dev_replace->srcdev;
901 up_read(&dev_replace->rwsem);
902
903 /*
904 * flush all outstanding I/O and inode extent mappings before the
905 * copy operation is declared as being finished
906 */
907 ret = btrfs_start_delalloc_roots(fs_info, LONG_MAX, false);
908 if (ret) {
909 /* Stays started/resumable; keep both denied. */
910 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
911 return ret;
912 }
913 btrfs_wait_ordered_roots(fs_info, U64_MAX, NULL);
914
915 /*
916 * We have to use this loop approach because at this point src_device
917 * has to be available for transaction commit to complete, yet new
918 * chunks shouldn't be allocated on the device.
919 */
920 while (1) {
921 trans = btrfs_start_transaction(root, 0);
922 if (IS_ERR(trans)) {
923 /* Stays started/resumable; keep both denied. */
924 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
925 return PTR_ERR(trans);
926 }
927 ret = btrfs_commit_transaction(trans);
928 WARN_ON(ret);
929
930 /* Prevent write_all_supers() during the finishing procedure */
931 mutex_lock(&fs_devices->device_list_mutex);
932 /* Prevent new chunks being allocated on the source device */
933 mutex_lock(&fs_info->chunk_mutex);
934
935 if (!list_empty(&src_device->post_commit_list)) {
936 mutex_unlock(&fs_devices->device_list_mutex);
937 mutex_unlock(&fs_info->chunk_mutex);
938 } else {
939 break;
940 }
941 }
942
943 down_write(&dev_replace->rwsem);
944 dev_replace->replace_state =
945 scrub_ret ? BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED
946 : BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED;
947 dev_replace->tgtdev = NULL;
948 dev_replace->srcdev = NULL;
949 dev_replace->time_stopped = ktime_get_real_seconds();
950 dev_replace->item_needs_writeback = 1;
951
952 /*
953 * Update allocation state in the new device and replace the old device
954 * with the new one in the mapping tree.
955 */
956 if (!scrub_ret) {
957 scrub_ret = btrfs_set_target_alloc_state(src_device, tgt_device);
958 if (scrub_ret)
959 goto error;
960 btrfs_dev_replace_update_device_in_mapping_tree(fs_info,
961 src_device,
962 tgt_device);
963 } else {
964 if (scrub_ret != -ECANCELED)
965 btrfs_err(fs_info,
966 "btrfs_scrub_dev(%s, %llu, %s) failed %d",
967 btrfs_dev_name(src_device),
968 src_device->devid,
969 btrfs_dev_name(tgt_device), scrub_ret);
970error:
971 up_write(&dev_replace->rwsem);
972 mutex_unlock(&fs_info->chunk_mutex);
973 mutex_unlock(&fs_devices->device_list_mutex);
974 btrfs_rm_dev_replace_blocked(fs_info);
975 if (tgt_device)
976 btrfs_destroy_dev_replace_tgtdev(tgt_device, true);
977 /* The source stays a member; re-allow freezing it. */
978 if (src_device->bdev)
979 bdev_allow_freeze(src_device->bdev);
980 btrfs_rm_dev_replace_unblocked(fs_info);
981 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
982
983 return scrub_ret;
984 }
985
986 btrfs_info(fs_info,
987 "dev_replace from %s (devid %llu) to %s finished",
988 btrfs_dev_name(src_device),
989 src_device->devid,
990 btrfs_dev_name(tgt_device));
991 clear_bit(BTRFS_DEV_STATE_REPLACE_TGT, &tgt_device->dev_state);
992 tgt_device->devid = src_device->devid;
993 src_device->devid = BTRFS_DEV_REPLACE_DEVID;
994 memcpy(uuid_tmp, tgt_device->uuid, sizeof(uuid_tmp));
995 memcpy(tgt_device->uuid, src_device->uuid, sizeof(tgt_device->uuid));
996 memcpy(src_device->uuid, uuid_tmp, sizeof(src_device->uuid));
997 btrfs_device_set_total_bytes(tgt_device, src_device->total_bytes);
998 btrfs_device_set_disk_total_bytes(tgt_device,
999 src_device->disk_total_bytes);
1000 btrfs_device_set_bytes_used(tgt_device, src_device->bytes_used);
1001 tgt_device->commit_bytes_used = src_device->bytes_used;
1002
1003 btrfs_assign_next_active_device(src_device, tgt_device);
1004
1005 list_add(&tgt_device->dev_alloc_list, &fs_devices->alloc_list);
1006 fs_devices->rw_devices++;
1007
1008 dev_replace->replace_task = NULL;
1009 up_write(&dev_replace->rwsem);
1010 btrfs_rm_dev_replace_blocked(fs_info);
1011
1012 btrfs_rm_dev_replace_remove_srcdev(src_device);
1013
1014 btrfs_rm_dev_replace_unblocked(fs_info);
1015
1016 /*
1017 * Increment dev_stats_ccnt so that btrfs_run_dev_stats() will
1018 * update on-disk dev stats value during commit transaction
1019 */
1020 atomic_inc(&tgt_device->dev_stats_ccnt);
1021
1022 /*
1023 * this is again a consistent state where no dev_replace procedure
1024 * is running, the target device is part of the filesystem, the
1025 * source device is not part of the filesystem anymore and its 1st
1026 * superblock is scratched out so that it is no longer marked to
1027 * belong to this filesystem.
1028 */
1029 mutex_unlock(&fs_info->chunk_mutex);
1030 mutex_unlock(&fs_devices->device_list_mutex);
1031
1032 /* replace the sysfs entry */
1033 btrfs_sysfs_remove_device(src_device);
1034 btrfs_sysfs_update_devid(tgt_device);
1035 if (test_bit(BTRFS_DEV_STATE_WRITEABLE, &src_device->dev_state))
1036 btrfs_scratch_superblocks(fs_info, src_device);
1037
1038 /* write back the superblocks */
1039 trans = btrfs_start_transaction(root, 0);
1040 if (!IS_ERR(trans)) {
1041 /*
1042 * Ignore any error here, if we failed to remove the DEV_STATS
1043 * item for devid 0, it's not a big deal. We have other ways
1044 * to address it.
1045 */
1046 btrfs_remove_dev_stat_item(trans, BTRFS_DEV_REPLACE_DEVID);
1047 btrfs_commit_transaction(trans);
1048 }
1049
1050 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
1051
1052 /* The target is now a member; the source is freed (allow + release). */
1053 bdev_allow_freeze(tgt_device->bdev);
1054 btrfs_rm_dev_replace_free_srcdev(src_device);
1055
1056 return 0;
1057}
1058
1059/*
1060 * Read progress of device replace status according to the state and last
1061 * stored position. The value format is the same as for
1062 * btrfs_dev_replace::progress_1000
1063 */
1064static u64 btrfs_dev_replace_progress(struct btrfs_fs_info *fs_info)
1065{
1066 struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
1067 u64 ret = 0;
1068
1069 switch (dev_replace->replace_state) {
1070 case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
1071 case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
1072 ret = 0;
1073 break;
1074 case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
1075 ret = 1000;
1076 break;
1077 case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
1078 case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
1079 ret = div64_u64(dev_replace->cursor_left,
1080 div_u64(btrfs_device_get_total_bytes(
1081 dev_replace->srcdev), 1000));
1082 break;
1083 }
1084
1085 return ret;
1086}
1087
1088void btrfs_dev_replace_status(struct btrfs_fs_info *fs_info,
1089 struct btrfs_ioctl_dev_replace_args *args)
1090{
1091 struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
1092
1093 down_read(&dev_replace->rwsem);
1094 /* even if !dev_replace_is_valid, the values are good enough for
1095 * the replace_status ioctl */
1096 args->result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR;
1097 args->status.replace_state = dev_replace->replace_state;
1098 args->status.time_started = dev_replace->time_started;
1099 args->status.time_stopped = dev_replace->time_stopped;
1100 args->status.num_write_errors =
1101 atomic64_read(&dev_replace->num_write_errors);
1102 args->status.num_uncorrectable_read_errors =
1103 atomic64_read(&dev_replace->num_uncorrectable_read_errors);
1104 args->status.progress_1000 = btrfs_dev_replace_progress(fs_info);
1105 up_read(&dev_replace->rwsem);
1106}
1107
1108int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info)
1109{
1110 struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
1111 struct btrfs_device *tgt_device = NULL;
1112 struct btrfs_device *src_device = NULL;
1113 struct btrfs_trans_handle *trans;
1114 struct btrfs_root *root = fs_info->tree_root;
1115 int result;
1116 int ret;
1117
1118 if (sb_rdonly(fs_info->sb))
1119 return -EROFS;
1120
1121 mutex_lock(&dev_replace->lock_finishing_cancel_unmount);
1122 down_write(&dev_replace->rwsem);
1123 switch (dev_replace->replace_state) {
1124 case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
1125 case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
1126 case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
1127 result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NOT_STARTED;
1128 up_write(&dev_replace->rwsem);
1129 break;
1130 case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
1131 tgt_device = dev_replace->tgtdev;
1132 src_device = dev_replace->srcdev;
1133 up_write(&dev_replace->rwsem);
1134 ret = btrfs_scrub_cancel(fs_info);
1135 if (ret < 0) {
1136 result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NOT_STARTED;
1137 } else {
1138 result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR;
1139 /*
1140 * btrfs_dev_replace_finishing() will handle the
1141 * cleanup part
1142 */
1143 btrfs_info(fs_info,
1144 "dev_replace from %s (devid %llu) to %s canceled",
1145 btrfs_dev_name(src_device), src_device->devid,
1146 btrfs_dev_name(tgt_device));
1147 }
1148 break;
1149 case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
1150 /*
1151 * Scrub doing the replace isn't running so we need to do the
1152 * cleanup step of btrfs_dev_replace_finishing() here
1153 */
1154 result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR;
1155 tgt_device = dev_replace->tgtdev;
1156 src_device = dev_replace->srcdev;
1157 dev_replace->tgtdev = NULL;
1158 dev_replace->srcdev = NULL;
1159 dev_replace->replace_state =
1160 BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED;
1161 dev_replace->time_stopped = ktime_get_real_seconds();
1162 dev_replace->item_needs_writeback = 1;
1163
1164 up_write(&dev_replace->rwsem);
1165
1166 /* Scrub for replace must not be running in suspended state */
1167 btrfs_scrub_cancel(fs_info);
1168
1169 trans = btrfs_start_transaction(root, 0);
1170 if (IS_ERR(trans)) {
1171 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
1172 return PTR_ERR(trans);
1173 }
1174 ret = btrfs_commit_transaction(trans);
1175 WARN_ON(ret);
1176
1177 btrfs_info(fs_info,
1178 "suspended dev_replace from %s (devid %llu) to %s canceled",
1179 btrfs_dev_name(src_device), src_device->devid,
1180 btrfs_dev_name(tgt_device));
1181
1182 /* A suspended replace never re-denied freezing; do not allow. */
1183 if (tgt_device)
1184 btrfs_destroy_dev_replace_tgtdev(tgt_device, false);
1185 break;
1186 default:
1187 up_write(&dev_replace->rwsem);
1188 result = -EINVAL;
1189 }
1190
1191 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
1192 return result;
1193}
1194
1195void btrfs_dev_replace_suspend_for_unmount(struct btrfs_fs_info *fs_info)
1196{
1197 struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
1198
1199 mutex_lock(&dev_replace->lock_finishing_cancel_unmount);
1200 down_write(&dev_replace->rwsem);
1201
1202 switch (dev_replace->replace_state) {
1203 case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
1204 case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
1205 case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
1206 case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
1207 break;
1208 case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
1209 dev_replace->replace_state =
1210 BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED;
1211 dev_replace->time_stopped = ktime_get_real_seconds();
1212 dev_replace->item_needs_writeback = 1;
1213 btrfs_info(fs_info, "suspending dev_replace for unmount");
1214 /* Reopened freezable next mount; resume re-denies. */
1215 if (dev_replace->srcdev && dev_replace->srcdev->bdev)
1216 bdev_allow_freeze(dev_replace->srcdev->bdev);
1217 if (dev_replace->tgtdev && dev_replace->tgtdev->bdev)
1218 bdev_allow_freeze(dev_replace->tgtdev->bdev);
1219 break;
1220 }
1221
1222 up_write(&dev_replace->rwsem);
1223 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
1224}
1225
1226/* resume dev_replace procedure that was interrupted by unmount */
1227int btrfs_resume_dev_replace_async(struct btrfs_fs_info *fs_info)
1228{
1229 struct task_struct *task;
1230 struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
1231 int ret = 0;
1232
1233 down_write(&dev_replace->rwsem);
1234
1235 switch (dev_replace->replace_state) {
1236 case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
1237 case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
1238 case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
1239 up_write(&dev_replace->rwsem);
1240 return 0;
1241 case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
1242 break;
1243 case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
1244 dev_replace->replace_state =
1245 BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED;
1246 break;
1247 }
1248 if (!dev_replace->tgtdev || !dev_replace->tgtdev->bdev) {
1249 btrfs_info(fs_info,
1250 "cannot continue dev_replace, tgtdev is missing");
1251 btrfs_info(fs_info,
1252 "you may cancel the operation after 'mount -o degraded'");
1253 dev_replace->replace_state =
1254 BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED;
1255 up_write(&dev_replace->rwsem);
1256 return 0;
1257 }
1258 up_write(&dev_replace->rwsem);
1259
1260 /*
1261 * This could collide with a paused balance, but the exclusive op logic
1262 * should never allow both to start and pause. We don't want to allow
1263 * dev-replace to start anyway.
1264 */
1265 if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_DEV_REPLACE)) {
1266 down_write(&dev_replace->rwsem);
1267 dev_replace->replace_state =
1268 BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED;
1269 up_write(&dev_replace->rwsem);
1270 btrfs_info(fs_info,
1271 "cannot resume dev-replace, other exclusive operation running");
1272 return 0;
1273 }
1274
1275 /* Re-deny for the resumed replace; stay suspended if frozen now. */
1276 if (dev_replace->srcdev->bdev &&
1277 bdev_deny_freeze(dev_replace->srcdev->bdev))
1278 goto suspend;
1279 if (bdev_deny_freeze(dev_replace->tgtdev->bdev)) {
1280 if (dev_replace->srcdev->bdev)
1281 bdev_allow_freeze(dev_replace->srcdev->bdev);
1282 goto suspend;
1283 }
1284
1285 task = kthread_run(btrfs_dev_replace_kthread, fs_info, "btrfs-devrepl");
1286 if (IS_ERR(task)) {
1287 bdev_allow_freeze(dev_replace->tgtdev->bdev);
1288 if (dev_replace->srcdev->bdev)
1289 bdev_allow_freeze(dev_replace->srcdev->bdev);
1290 /* Undo the deny and suspend, but still fail the mount. */
1291 ret = PTR_ERR(task);
1292 goto suspend;
1293 }
1294 return 0;
1295
1296suspend:
1297 btrfs_exclop_finish(fs_info);
1298 down_write(&dev_replace->rwsem);
1299 dev_replace->replace_state = BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED;
1300 up_write(&dev_replace->rwsem);
1301 return ret;
1302}
1303
1304static int btrfs_dev_replace_kthread(void *data)
1305{
1306 struct btrfs_fs_info *fs_info = data;
1307 struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
1308 u64 progress;
1309 int ret;
1310
1311 progress = btrfs_dev_replace_progress(fs_info);
1312 progress = div_u64(progress, 10);
1313 btrfs_info(fs_info,
1314 "continuing dev_replace from %s (devid %llu) to target %s @%u%%",
1315 btrfs_dev_name(dev_replace->srcdev),
1316 dev_replace->srcdev->devid,
1317 btrfs_dev_name(dev_replace->tgtdev),
1318 (unsigned int)progress);
1319
1320 ret = btrfs_scrub_dev(fs_info, dev_replace->srcdev->devid,
1321 dev_replace->committed_cursor_left,
1322 btrfs_device_get_total_bytes(dev_replace->srcdev),
1323 &dev_replace->scrub_progress, false, true);
1324 ret = btrfs_dev_replace_finishing(fs_info, ret);
1325 WARN_ON(ret && ret != -ECANCELED);
1326
1327 btrfs_exclop_finish(fs_info);
1328 return 0;
1329}
1330
1331bool __pure btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace)
1332{
1333 if (!dev_replace->is_valid)
1334 return false;
1335
1336 switch (dev_replace->replace_state) {
1337 case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
1338 case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
1339 case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
1340 return false;
1341 case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
1342 case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
1343 /*
1344 * return true even if tgtdev is missing (this is
1345 * something that can happen if the dev_replace
1346 * procedure is suspended by an umount and then
1347 * the tgtdev is missing (or "btrfs dev scan") was
1348 * not called and the filesystem is remounted
1349 * in degraded state. This does not stop the
1350 * dev_replace procedure. It needs to be canceled
1351 * manually if the cancellation is wanted.
1352 */
1353 break;
1354 }
1355 return true;
1356}
1357
1358void btrfs_bio_counter_sub(struct btrfs_fs_info *fs_info, s64 amount)
1359{
1360 percpu_counter_sub(&fs_info->dev_replace.bio_counter, amount);
1361 cond_wake_up_nomb(&fs_info->dev_replace.replace_wait);
1362}
1363
1364void btrfs_bio_counter_inc_blocked(struct btrfs_fs_info *fs_info)
1365{
1366 while (1) {
1367 percpu_counter_inc(&fs_info->dev_replace.bio_counter);
1368 if (likely(!test_bit(BTRFS_FS_STATE_DEV_REPLACING,
1369 &fs_info->fs_state)))
1370 break;
1371
1372 btrfs_bio_counter_dec(fs_info);
1373 wait_event(fs_info->dev_replace.replace_wait,
1374 !test_bit(BTRFS_FS_STATE_DEV_REPLACING,
1375 &fs_info->fs_state));
1376 }
1377}