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