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