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

source code of linux/fs/btrfs/dev-replace.c