33d07c426c59ee949bf2aecbb13a4c44a080a928
[sfrench/cifs-2.6.git] / fs / btrfs / dev-replace.c
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 "ctree.h"
13 #include "extent_map.h"
14 #include "disk-io.h"
15 #include "transaction.h"
16 #include "print-tree.h"
17 #include "volumes.h"
18 #include "async-thread.h"
19 #include "check-integrity.h"
20 #include "rcu-string.h"
21 #include "dev-replace.h"
22 #include "sysfs.h"
23
24 static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
25                                        int scrub_ret);
26 static void btrfs_dev_replace_update_device_in_mapping_tree(
27                                                 struct btrfs_fs_info *fs_info,
28                                                 struct btrfs_device *srcdev,
29                                                 struct btrfs_device *tgtdev);
30 static int btrfs_dev_replace_kthread(void *data);
31
32 int btrfs_init_dev_replace(struct btrfs_fs_info *fs_info)
33 {
34         struct btrfs_key key;
35         struct btrfs_root *dev_root = fs_info->dev_root;
36         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
37         struct extent_buffer *eb;
38         int slot;
39         int ret = 0;
40         struct btrfs_path *path = NULL;
41         int item_size;
42         struct btrfs_dev_replace_item *ptr;
43         u64 src_devid;
44
45         path = btrfs_alloc_path();
46         if (!path) {
47                 ret = -ENOMEM;
48                 goto out;
49         }
50
51         key.objectid = 0;
52         key.type = BTRFS_DEV_REPLACE_KEY;
53         key.offset = 0;
54         ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
55         if (ret) {
56 no_valid_dev_replace_entry_found:
57                 ret = 0;
58                 dev_replace->replace_state =
59                         BTRFS_DEV_REPLACE_ITEM_STATE_NEVER_STARTED;
60                 dev_replace->cont_reading_from_srcdev_mode =
61                     BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_ALWAYS;
62                 dev_replace->time_started = 0;
63                 dev_replace->time_stopped = 0;
64                 atomic64_set(&dev_replace->num_write_errors, 0);
65                 atomic64_set(&dev_replace->num_uncorrectable_read_errors, 0);
66                 dev_replace->cursor_left = 0;
67                 dev_replace->committed_cursor_left = 0;
68                 dev_replace->cursor_left_last_write_of_item = 0;
69                 dev_replace->cursor_right = 0;
70                 dev_replace->srcdev = NULL;
71                 dev_replace->tgtdev = NULL;
72                 dev_replace->is_valid = 0;
73                 dev_replace->item_needs_writeback = 0;
74                 goto out;
75         }
76         slot = path->slots[0];
77         eb = path->nodes[0];
78         item_size = btrfs_item_size_nr(eb, slot);
79         ptr = btrfs_item_ptr(eb, slot, struct btrfs_dev_replace_item);
80
81         if (item_size != sizeof(struct btrfs_dev_replace_item)) {
82                 btrfs_warn(fs_info,
83                         "dev_replace entry found has unexpected size, ignore entry");
84                 goto no_valid_dev_replace_entry_found;
85         }
86
87         src_devid = btrfs_dev_replace_src_devid(eb, ptr);
88         dev_replace->cont_reading_from_srcdev_mode =
89                 btrfs_dev_replace_cont_reading_from_srcdev_mode(eb, ptr);
90         dev_replace->replace_state = btrfs_dev_replace_replace_state(eb, ptr);
91         dev_replace->time_started = btrfs_dev_replace_time_started(eb, ptr);
92         dev_replace->time_stopped =
93                 btrfs_dev_replace_time_stopped(eb, ptr);
94         atomic64_set(&dev_replace->num_write_errors,
95                      btrfs_dev_replace_num_write_errors(eb, ptr));
96         atomic64_set(&dev_replace->num_uncorrectable_read_errors,
97                      btrfs_dev_replace_num_uncorrectable_read_errors(eb, ptr));
98         dev_replace->cursor_left = btrfs_dev_replace_cursor_left(eb, ptr);
99         dev_replace->committed_cursor_left = dev_replace->cursor_left;
100         dev_replace->cursor_left_last_write_of_item = dev_replace->cursor_left;
101         dev_replace->cursor_right = btrfs_dev_replace_cursor_right(eb, ptr);
102         dev_replace->is_valid = 1;
103
104         dev_replace->item_needs_writeback = 0;
105         switch (dev_replace->replace_state) {
106         case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
107         case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
108         case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
109                 dev_replace->srcdev = NULL;
110                 dev_replace->tgtdev = NULL;
111                 break;
112         case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
113         case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
114                 dev_replace->srcdev = btrfs_find_device(fs_info, src_devid,
115                                                         NULL, NULL);
116                 dev_replace->tgtdev = btrfs_find_device(fs_info,
117                                                         BTRFS_DEV_REPLACE_DEVID,
118                                                         NULL, NULL);
119                 /*
120                  * allow 'btrfs dev replace_cancel' if src/tgt device is
121                  * missing
122                  */
123                 if (!dev_replace->srcdev &&
124                     !btrfs_test_opt(fs_info, DEGRADED)) {
125                         ret = -EIO;
126                         btrfs_warn(fs_info,
127                            "cannot mount because device replace operation is ongoing and");
128                         btrfs_warn(fs_info,
129                            "srcdev (devid %llu) is missing, need to run 'btrfs dev scan'?",
130                            src_devid);
131                 }
132                 if (!dev_replace->tgtdev &&
133                     !btrfs_test_opt(fs_info, DEGRADED)) {
134                         ret = -EIO;
135                         btrfs_warn(fs_info,
136                            "cannot mount because device replace operation is ongoing and");
137                         btrfs_warn(fs_info,
138                            "tgtdev (devid %llu) is missing, need to run 'btrfs dev scan'?",
139                                 BTRFS_DEV_REPLACE_DEVID);
140                 }
141                 if (dev_replace->tgtdev) {
142                         if (dev_replace->srcdev) {
143                                 dev_replace->tgtdev->total_bytes =
144                                         dev_replace->srcdev->total_bytes;
145                                 dev_replace->tgtdev->disk_total_bytes =
146                                         dev_replace->srcdev->disk_total_bytes;
147                                 dev_replace->tgtdev->commit_total_bytes =
148                                         dev_replace->srcdev->commit_total_bytes;
149                                 dev_replace->tgtdev->bytes_used =
150                                         dev_replace->srcdev->bytes_used;
151                                 dev_replace->tgtdev->commit_bytes_used =
152                                         dev_replace->srcdev->commit_bytes_used;
153                         }
154                         set_bit(BTRFS_DEV_STATE_REPLACE_TGT,
155                                 &dev_replace->tgtdev->dev_state);
156
157                         WARN_ON(fs_info->fs_devices->rw_devices == 0);
158                         dev_replace->tgtdev->io_width = fs_info->sectorsize;
159                         dev_replace->tgtdev->io_align = fs_info->sectorsize;
160                         dev_replace->tgtdev->sector_size = fs_info->sectorsize;
161                         dev_replace->tgtdev->fs_info = fs_info;
162                         set_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
163                                 &dev_replace->tgtdev->dev_state);
164                 }
165                 break;
166         }
167
168 out:
169         btrfs_free_path(path);
170         return ret;
171 }
172
173 /*
174  * Initialize a new device for device replace target from a given source dev
175  * and path.
176  *
177  * Return 0 and new device in @device_out, otherwise return < 0
178  */
179 static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
180                                   const char *device_path,
181                                   struct btrfs_device *srcdev,
182                                   struct btrfs_device **device_out)
183 {
184         struct btrfs_device *device;
185         struct block_device *bdev;
186         struct list_head *devices;
187         struct rcu_string *name;
188         u64 devid = BTRFS_DEV_REPLACE_DEVID;
189         int ret = 0;
190
191         *device_out = NULL;
192         if (fs_info->fs_devices->seeding) {
193                 btrfs_err(fs_info, "the filesystem is a seed filesystem!");
194                 return -EINVAL;
195         }
196
197         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
198                                   fs_info->bdev_holder);
199         if (IS_ERR(bdev)) {
200                 btrfs_err(fs_info, "target device %s is invalid!", device_path);
201                 return PTR_ERR(bdev);
202         }
203
204         filemap_write_and_wait(bdev->bd_inode->i_mapping);
205
206         devices = &fs_info->fs_devices->devices;
207         list_for_each_entry(device, devices, dev_list) {
208                 if (device->bdev == bdev) {
209                         btrfs_err(fs_info,
210                                   "target device is in the filesystem!");
211                         ret = -EEXIST;
212                         goto error;
213                 }
214         }
215
216
217         if (i_size_read(bdev->bd_inode) <
218             btrfs_device_get_total_bytes(srcdev)) {
219                 btrfs_err(fs_info,
220                           "target device is smaller than source device!");
221                 ret = -EINVAL;
222                 goto error;
223         }
224
225
226         device = btrfs_alloc_device(NULL, &devid, NULL);
227         if (IS_ERR(device)) {
228                 ret = PTR_ERR(device);
229                 goto error;
230         }
231
232         name = rcu_string_strdup(device_path, GFP_KERNEL);
233         if (!name) {
234                 btrfs_free_device(device);
235                 ret = -ENOMEM;
236                 goto error;
237         }
238         rcu_assign_pointer(device->name, name);
239
240         mutex_lock(&fs_info->fs_devices->device_list_mutex);
241         set_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state);
242         device->generation = 0;
243         device->io_width = fs_info->sectorsize;
244         device->io_align = fs_info->sectorsize;
245         device->sector_size = fs_info->sectorsize;
246         device->total_bytes = btrfs_device_get_total_bytes(srcdev);
247         device->disk_total_bytes = btrfs_device_get_disk_total_bytes(srcdev);
248         device->bytes_used = btrfs_device_get_bytes_used(srcdev);
249         device->commit_total_bytes = srcdev->commit_total_bytes;
250         device->commit_bytes_used = device->bytes_used;
251         device->fs_info = fs_info;
252         device->bdev = bdev;
253         set_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state);
254         set_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state);
255         device->mode = FMODE_EXCL;
256         device->dev_stats_valid = 1;
257         set_blocksize(device->bdev, BTRFS_BDEV_BLOCKSIZE);
258         device->fs_devices = fs_info->fs_devices;
259         list_add(&device->dev_list, &fs_info->fs_devices->devices);
260         fs_info->fs_devices->num_devices++;
261         fs_info->fs_devices->open_devices++;
262         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
263
264         *device_out = device;
265         return 0;
266
267 error:
268         blkdev_put(bdev, FMODE_EXCL);
269         return ret;
270 }
271
272 /*
273  * called from commit_transaction. Writes changed device replace state to
274  * disk.
275  */
276 int btrfs_run_dev_replace(struct btrfs_trans_handle *trans,
277                           struct btrfs_fs_info *fs_info)
278 {
279         int ret;
280         struct btrfs_root *dev_root = fs_info->dev_root;
281         struct btrfs_path *path;
282         struct btrfs_key key;
283         struct extent_buffer *eb;
284         struct btrfs_dev_replace_item *ptr;
285         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
286
287         btrfs_dev_replace_read_lock(dev_replace);
288         if (!dev_replace->is_valid ||
289             !dev_replace->item_needs_writeback) {
290                 btrfs_dev_replace_read_unlock(dev_replace);
291                 return 0;
292         }
293         btrfs_dev_replace_read_unlock(dev_replace);
294
295         key.objectid = 0;
296         key.type = BTRFS_DEV_REPLACE_KEY;
297         key.offset = 0;
298
299         path = btrfs_alloc_path();
300         if (!path) {
301                 ret = -ENOMEM;
302                 goto out;
303         }
304         ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
305         if (ret < 0) {
306                 btrfs_warn(fs_info,
307                            "error %d while searching for dev_replace item!",
308                            ret);
309                 goto out;
310         }
311
312         if (ret == 0 &&
313             btrfs_item_size_nr(path->nodes[0], path->slots[0]) < sizeof(*ptr)) {
314                 /*
315                  * need to delete old one and insert a new one.
316                  * Since no attempt is made to recover any old state, if the
317                  * dev_replace state is 'running', the data on the target
318                  * drive is lost.
319                  * It would be possible to recover the state: just make sure
320                  * that the beginning of the item is never changed and always
321                  * contains all the essential information. Then read this
322                  * minimal set of information and use it as a base for the
323                  * new state.
324                  */
325                 ret = btrfs_del_item(trans, dev_root, path);
326                 if (ret != 0) {
327                         btrfs_warn(fs_info,
328                                    "delete too small dev_replace item failed %d!",
329                                    ret);
330                         goto out;
331                 }
332                 ret = 1;
333         }
334
335         if (ret == 1) {
336                 /* need to insert a new item */
337                 btrfs_release_path(path);
338                 ret = btrfs_insert_empty_item(trans, dev_root, path,
339                                               &key, sizeof(*ptr));
340                 if (ret < 0) {
341                         btrfs_warn(fs_info,
342                                    "insert dev_replace item failed %d!", ret);
343                         goto out;
344                 }
345         }
346
347         eb = path->nodes[0];
348         ptr = btrfs_item_ptr(eb, path->slots[0],
349                              struct btrfs_dev_replace_item);
350
351         btrfs_dev_replace_write_lock(dev_replace);
352         if (dev_replace->srcdev)
353                 btrfs_set_dev_replace_src_devid(eb, ptr,
354                         dev_replace->srcdev->devid);
355         else
356                 btrfs_set_dev_replace_src_devid(eb, ptr, (u64)-1);
357         btrfs_set_dev_replace_cont_reading_from_srcdev_mode(eb, ptr,
358                 dev_replace->cont_reading_from_srcdev_mode);
359         btrfs_set_dev_replace_replace_state(eb, ptr,
360                 dev_replace->replace_state);
361         btrfs_set_dev_replace_time_started(eb, ptr, dev_replace->time_started);
362         btrfs_set_dev_replace_time_stopped(eb, ptr, dev_replace->time_stopped);
363         btrfs_set_dev_replace_num_write_errors(eb, ptr,
364                 atomic64_read(&dev_replace->num_write_errors));
365         btrfs_set_dev_replace_num_uncorrectable_read_errors(eb, ptr,
366                 atomic64_read(&dev_replace->num_uncorrectable_read_errors));
367         dev_replace->cursor_left_last_write_of_item =
368                 dev_replace->cursor_left;
369         btrfs_set_dev_replace_cursor_left(eb, ptr,
370                 dev_replace->cursor_left_last_write_of_item);
371         btrfs_set_dev_replace_cursor_right(eb, ptr,
372                 dev_replace->cursor_right);
373         dev_replace->item_needs_writeback = 0;
374         btrfs_dev_replace_write_unlock(dev_replace);
375
376         btrfs_mark_buffer_dirty(eb);
377
378 out:
379         btrfs_free_path(path);
380
381         return ret;
382 }
383
384 static char* btrfs_dev_name(struct btrfs_device *device)
385 {
386         if (!device || test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state))
387                 return "<missing disk>";
388         else
389                 return rcu_str_deref(device->name);
390 }
391
392 static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
393                 const char *tgtdev_name, u64 srcdevid, const char *srcdev_name,
394                 int read_src)
395 {
396         struct btrfs_root *root = fs_info->dev_root;
397         struct btrfs_trans_handle *trans;
398         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
399         int ret;
400         struct btrfs_device *tgt_device = NULL;
401         struct btrfs_device *src_device = NULL;
402         bool need_unlock;
403
404         src_device = btrfs_find_device_by_devspec(fs_info, srcdevid,
405                                                   srcdev_name);
406         if (IS_ERR(src_device))
407                 return PTR_ERR(src_device);
408
409         if (btrfs_pinned_by_swapfile(fs_info, src_device)) {
410                 btrfs_warn_in_rcu(fs_info,
411           "cannot replace device %s (devid %llu) due to active swapfile",
412                         btrfs_dev_name(src_device), src_device->devid);
413                 return -ETXTBSY;
414         }
415
416         ret = btrfs_init_dev_replace_tgtdev(fs_info, tgtdev_name,
417                                             src_device, &tgt_device);
418         if (ret)
419                 return ret;
420
421         /*
422          * Here we commit the transaction to make sure commit_total_bytes
423          * of all the devices are updated.
424          */
425         trans = btrfs_attach_transaction(root);
426         if (!IS_ERR(trans)) {
427                 ret = btrfs_commit_transaction(trans);
428                 if (ret)
429                         return ret;
430         } else if (PTR_ERR(trans) != -ENOENT) {
431                 return PTR_ERR(trans);
432         }
433
434         need_unlock = true;
435         btrfs_dev_replace_write_lock(dev_replace);
436         switch (dev_replace->replace_state) {
437         case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
438         case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
439         case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
440                 break;
441         case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
442         case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
443                 ASSERT(0);
444                 ret = BTRFS_IOCTL_DEV_REPLACE_RESULT_ALREADY_STARTED;
445                 goto leave;
446         }
447
448         dev_replace->cont_reading_from_srcdev_mode = read_src;
449         WARN_ON(!src_device);
450         dev_replace->srcdev = src_device;
451         dev_replace->tgtdev = tgt_device;
452
453         btrfs_info_in_rcu(fs_info,
454                       "dev_replace from %s (devid %llu) to %s started",
455                       btrfs_dev_name(src_device),
456                       src_device->devid,
457                       rcu_str_deref(tgt_device->name));
458
459         /*
460          * from now on, the writes to the srcdev are all duplicated to
461          * go to the tgtdev as well (refer to btrfs_map_block()).
462          */
463         dev_replace->replace_state = BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED;
464         dev_replace->time_started = ktime_get_real_seconds();
465         dev_replace->cursor_left = 0;
466         dev_replace->committed_cursor_left = 0;
467         dev_replace->cursor_left_last_write_of_item = 0;
468         dev_replace->cursor_right = 0;
469         dev_replace->is_valid = 1;
470         dev_replace->item_needs_writeback = 1;
471         atomic64_set(&dev_replace->num_write_errors, 0);
472         atomic64_set(&dev_replace->num_uncorrectable_read_errors, 0);
473         btrfs_dev_replace_write_unlock(dev_replace);
474         need_unlock = false;
475
476         ret = btrfs_sysfs_add_device_link(tgt_device->fs_devices, tgt_device);
477         if (ret)
478                 btrfs_err(fs_info, "kobj add dev failed %d", ret);
479
480         btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
481
482         /* force writing the updated state information to disk */
483         trans = btrfs_start_transaction(root, 0);
484         if (IS_ERR(trans)) {
485                 ret = PTR_ERR(trans);
486                 need_unlock = true;
487                 btrfs_dev_replace_write_lock(dev_replace);
488                 dev_replace->replace_state =
489                         BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED;
490                 dev_replace->srcdev = NULL;
491                 dev_replace->tgtdev = NULL;
492                 goto leave;
493         }
494
495         ret = btrfs_commit_transaction(trans);
496         WARN_ON(ret);
497
498         /* the disk copy procedure reuses the scrub code */
499         ret = btrfs_scrub_dev(fs_info, src_device->devid, 0,
500                               btrfs_device_get_total_bytes(src_device),
501                               &dev_replace->scrub_progress, 0, 1);
502
503         ret = btrfs_dev_replace_finishing(fs_info, ret);
504         if (ret == -EINPROGRESS) {
505                 ret = BTRFS_IOCTL_DEV_REPLACE_RESULT_SCRUB_INPROGRESS;
506         } else {
507                 WARN_ON(ret);
508         }
509
510         return ret;
511
512 leave:
513         if (need_unlock)
514                 btrfs_dev_replace_write_unlock(dev_replace);
515         btrfs_destroy_dev_replace_tgtdev(tgt_device);
516         return ret;
517 }
518
519 int btrfs_dev_replace_by_ioctl(struct btrfs_fs_info *fs_info,
520                             struct btrfs_ioctl_dev_replace_args *args)
521 {
522         int ret;
523
524         switch (args->start.cont_reading_from_srcdev_mode) {
525         case BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_ALWAYS:
526         case BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_AVOID:
527                 break;
528         default:
529                 return -EINVAL;
530         }
531
532         if ((args->start.srcdevid == 0 && args->start.srcdev_name[0] == '\0') ||
533             args->start.tgtdev_name[0] == '\0')
534                 return -EINVAL;
535
536         ret = btrfs_dev_replace_start(fs_info, args->start.tgtdev_name,
537                                         args->start.srcdevid,
538                                         args->start.srcdev_name,
539                                         args->start.cont_reading_from_srcdev_mode);
540         args->result = ret;
541         /* don't warn if EINPROGRESS, someone else might be running scrub */
542         if (ret == BTRFS_IOCTL_DEV_REPLACE_RESULT_SCRUB_INPROGRESS)
543                 ret = 0;
544
545         return ret;
546 }
547
548 /*
549  * blocked until all in-flight bios operations are finished.
550  */
551 static void btrfs_rm_dev_replace_blocked(struct btrfs_fs_info *fs_info)
552 {
553         set_bit(BTRFS_FS_STATE_DEV_REPLACING, &fs_info->fs_state);
554         wait_event(fs_info->dev_replace.replace_wait, !percpu_counter_sum(
555                    &fs_info->dev_replace.bio_counter));
556 }
557
558 /*
559  * we have removed target device, it is safe to allow new bios request.
560  */
561 static void btrfs_rm_dev_replace_unblocked(struct btrfs_fs_info *fs_info)
562 {
563         clear_bit(BTRFS_FS_STATE_DEV_REPLACING, &fs_info->fs_state);
564         wake_up(&fs_info->dev_replace.replace_wait);
565 }
566
567 static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
568                                        int scrub_ret)
569 {
570         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
571         struct btrfs_device *tgt_device;
572         struct btrfs_device *src_device;
573         struct btrfs_root *root = fs_info->tree_root;
574         u8 uuid_tmp[BTRFS_UUID_SIZE];
575         struct btrfs_trans_handle *trans;
576         int ret = 0;
577
578         /* don't allow cancel or unmount to disturb the finishing procedure */
579         mutex_lock(&dev_replace->lock_finishing_cancel_unmount);
580
581         btrfs_dev_replace_read_lock(dev_replace);
582         /* was the operation canceled, or is it finished? */
583         if (dev_replace->replace_state !=
584             BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED) {
585                 btrfs_dev_replace_read_unlock(dev_replace);
586                 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
587                 return 0;
588         }
589
590         tgt_device = dev_replace->tgtdev;
591         src_device = dev_replace->srcdev;
592         btrfs_dev_replace_read_unlock(dev_replace);
593
594         /*
595          * flush all outstanding I/O and inode extent mappings before the
596          * copy operation is declared as being finished
597          */
598         ret = btrfs_start_delalloc_roots(fs_info, -1);
599         if (ret) {
600                 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
601                 return ret;
602         }
603         btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
604
605         trans = btrfs_start_transaction(root, 0);
606         if (IS_ERR(trans)) {
607                 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
608                 return PTR_ERR(trans);
609         }
610         ret = btrfs_commit_transaction(trans);
611         WARN_ON(ret);
612
613         /* keep away write_all_supers() during the finishing procedure */
614         mutex_lock(&fs_info->fs_devices->device_list_mutex);
615         mutex_lock(&fs_info->chunk_mutex);
616         btrfs_dev_replace_write_lock(dev_replace);
617         dev_replace->replace_state =
618                 scrub_ret ? BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED
619                           : BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED;
620         dev_replace->tgtdev = NULL;
621         dev_replace->srcdev = NULL;
622         dev_replace->time_stopped = ktime_get_real_seconds();
623         dev_replace->item_needs_writeback = 1;
624
625         /* replace old device with new one in mapping tree */
626         if (!scrub_ret) {
627                 btrfs_dev_replace_update_device_in_mapping_tree(fs_info,
628                                                                 src_device,
629                                                                 tgt_device);
630         } else {
631                 btrfs_err_in_rcu(fs_info,
632                                  "btrfs_scrub_dev(%s, %llu, %s) failed %d",
633                                  btrfs_dev_name(src_device),
634                                  src_device->devid,
635                                  rcu_str_deref(tgt_device->name), scrub_ret);
636                 btrfs_dev_replace_write_unlock(dev_replace);
637                 mutex_unlock(&fs_info->chunk_mutex);
638                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
639                 btrfs_rm_dev_replace_blocked(fs_info);
640                 if (tgt_device)
641                         btrfs_destroy_dev_replace_tgtdev(tgt_device);
642                 btrfs_rm_dev_replace_unblocked(fs_info);
643                 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
644
645                 return scrub_ret;
646         }
647
648         btrfs_info_in_rcu(fs_info,
649                           "dev_replace from %s (devid %llu) to %s finished",
650                           btrfs_dev_name(src_device),
651                           src_device->devid,
652                           rcu_str_deref(tgt_device->name));
653         clear_bit(BTRFS_DEV_STATE_REPLACE_TGT, &tgt_device->dev_state);
654         tgt_device->devid = src_device->devid;
655         src_device->devid = BTRFS_DEV_REPLACE_DEVID;
656         memcpy(uuid_tmp, tgt_device->uuid, sizeof(uuid_tmp));
657         memcpy(tgt_device->uuid, src_device->uuid, sizeof(tgt_device->uuid));
658         memcpy(src_device->uuid, uuid_tmp, sizeof(src_device->uuid));
659         btrfs_device_set_total_bytes(tgt_device, src_device->total_bytes);
660         btrfs_device_set_disk_total_bytes(tgt_device,
661                                           src_device->disk_total_bytes);
662         btrfs_device_set_bytes_used(tgt_device, src_device->bytes_used);
663         ASSERT(list_empty(&src_device->resized_list));
664         tgt_device->commit_total_bytes = src_device->commit_total_bytes;
665         tgt_device->commit_bytes_used = src_device->bytes_used;
666
667         btrfs_assign_next_active_device(src_device, tgt_device);
668
669         list_add(&tgt_device->dev_alloc_list, &fs_info->fs_devices->alloc_list);
670         fs_info->fs_devices->rw_devices++;
671
672         btrfs_dev_replace_write_unlock(dev_replace);
673
674         btrfs_rm_dev_replace_blocked(fs_info);
675
676         btrfs_rm_dev_replace_remove_srcdev(src_device);
677
678         btrfs_rm_dev_replace_unblocked(fs_info);
679
680         /*
681          * Increment dev_stats_ccnt so that btrfs_run_dev_stats() will
682          * update on-disk dev stats value during commit transaction
683          */
684         atomic_inc(&tgt_device->dev_stats_ccnt);
685
686         /*
687          * this is again a consistent state where no dev_replace procedure
688          * is running, the target device is part of the filesystem, the
689          * source device is not part of the filesystem anymore and its 1st
690          * superblock is scratched out so that it is no longer marked to
691          * belong to this filesystem.
692          */
693         mutex_unlock(&fs_info->chunk_mutex);
694         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
695
696         /* replace the sysfs entry */
697         btrfs_sysfs_rm_device_link(fs_info->fs_devices, src_device);
698         btrfs_rm_dev_replace_free_srcdev(fs_info, src_device);
699
700         /* write back the superblocks */
701         trans = btrfs_start_transaction(root, 0);
702         if (!IS_ERR(trans))
703                 btrfs_commit_transaction(trans);
704
705         mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
706
707         return 0;
708 }
709
710 static void btrfs_dev_replace_update_device_in_mapping_tree(
711                                                 struct btrfs_fs_info *fs_info,
712                                                 struct btrfs_device *srcdev,
713                                                 struct btrfs_device *tgtdev)
714 {
715         struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
716         struct extent_map *em;
717         struct map_lookup *map;
718         u64 start = 0;
719         int i;
720
721         write_lock(&em_tree->lock);
722         do {
723                 em = lookup_extent_mapping(em_tree, start, (u64)-1);
724                 if (!em)
725                         break;
726                 map = em->map_lookup;
727                 for (i = 0; i < map->num_stripes; i++)
728                         if (srcdev == map->stripes[i].dev)
729                                 map->stripes[i].dev = tgtdev;
730                 start = em->start + em->len;
731                 free_extent_map(em);
732         } while (start);
733         write_unlock(&em_tree->lock);
734 }
735
736 /*
737  * Read progress of device replace status according to the state and last
738  * stored position. The value format is the same as for
739  * btrfs_dev_replace::progress_1000
740  */
741 static u64 btrfs_dev_replace_progress(struct btrfs_fs_info *fs_info)
742 {
743         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
744         u64 ret = 0;
745
746         switch (dev_replace->replace_state) {
747         case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
748         case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
749                 ret = 0;
750                 break;
751         case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
752                 ret = 1000;
753                 break;
754         case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
755         case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
756                 ret = div64_u64(dev_replace->cursor_left,
757                                 div_u64(btrfs_device_get_total_bytes(
758                                                 dev_replace->srcdev), 1000));
759                 break;
760         }
761
762         return ret;
763 }
764
765 void btrfs_dev_replace_status(struct btrfs_fs_info *fs_info,
766                               struct btrfs_ioctl_dev_replace_args *args)
767 {
768         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
769
770         btrfs_dev_replace_read_lock(dev_replace);
771         /* even if !dev_replace_is_valid, the values are good enough for
772          * the replace_status ioctl */
773         args->result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR;
774         args->status.replace_state = dev_replace->replace_state;
775         args->status.time_started = dev_replace->time_started;
776         args->status.time_stopped = dev_replace->time_stopped;
777         args->status.num_write_errors =
778                 atomic64_read(&dev_replace->num_write_errors);
779         args->status.num_uncorrectable_read_errors =
780                 atomic64_read(&dev_replace->num_uncorrectable_read_errors);
781         args->status.progress_1000 = btrfs_dev_replace_progress(fs_info);
782         btrfs_dev_replace_read_unlock(dev_replace);
783 }
784
785 int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info)
786 {
787         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
788         struct btrfs_device *tgt_device = NULL;
789         struct btrfs_device *src_device = NULL;
790         struct btrfs_trans_handle *trans;
791         struct btrfs_root *root = fs_info->tree_root;
792         int result;
793         int ret;
794
795         if (sb_rdonly(fs_info->sb))
796                 return -EROFS;
797
798         mutex_lock(&dev_replace->lock_finishing_cancel_unmount);
799         btrfs_dev_replace_write_lock(dev_replace);
800         switch (dev_replace->replace_state) {
801         case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
802         case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
803         case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
804                 result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NOT_STARTED;
805                 btrfs_dev_replace_write_unlock(dev_replace);
806                 goto leave;
807         case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
808         case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
809                 result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR;
810                 tgt_device = dev_replace->tgtdev;
811                 src_device = dev_replace->srcdev;
812                 dev_replace->tgtdev = NULL;
813                 dev_replace->srcdev = NULL;
814                 break;
815         }
816         dev_replace->replace_state = BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED;
817         dev_replace->time_stopped = ktime_get_real_seconds();
818         dev_replace->item_needs_writeback = 1;
819         btrfs_dev_replace_write_unlock(dev_replace);
820         btrfs_scrub_cancel(fs_info);
821
822         trans = btrfs_start_transaction(root, 0);
823         if (IS_ERR(trans)) {
824                 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
825                 return PTR_ERR(trans);
826         }
827         ret = btrfs_commit_transaction(trans);
828         WARN_ON(ret);
829
830         btrfs_info_in_rcu(fs_info,
831                 "dev_replace from %s (devid %llu) to %s canceled",
832                 btrfs_dev_name(src_device), src_device->devid,
833                 btrfs_dev_name(tgt_device));
834
835         if (tgt_device)
836                 btrfs_destroy_dev_replace_tgtdev(tgt_device);
837
838 leave:
839         mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
840         return result;
841 }
842
843 void btrfs_dev_replace_suspend_for_unmount(struct btrfs_fs_info *fs_info)
844 {
845         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
846
847         mutex_lock(&dev_replace->lock_finishing_cancel_unmount);
848         btrfs_dev_replace_write_lock(dev_replace);
849         switch (dev_replace->replace_state) {
850         case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
851         case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
852         case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
853         case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
854                 break;
855         case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
856                 dev_replace->replace_state =
857                         BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED;
858                 dev_replace->time_stopped = ktime_get_real_seconds();
859                 dev_replace->item_needs_writeback = 1;
860                 btrfs_info(fs_info, "suspending dev_replace for unmount");
861                 break;
862         }
863
864         btrfs_dev_replace_write_unlock(dev_replace);
865         mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
866 }
867
868 /* resume dev_replace procedure that was interrupted by unmount */
869 int btrfs_resume_dev_replace_async(struct btrfs_fs_info *fs_info)
870 {
871         struct task_struct *task;
872         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
873
874         btrfs_dev_replace_write_lock(dev_replace);
875         switch (dev_replace->replace_state) {
876         case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
877         case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
878         case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
879                 btrfs_dev_replace_write_unlock(dev_replace);
880                 return 0;
881         case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
882                 break;
883         case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
884                 dev_replace->replace_state =
885                         BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED;
886                 break;
887         }
888         if (!dev_replace->tgtdev || !dev_replace->tgtdev->bdev) {
889                 btrfs_info(fs_info,
890                            "cannot continue dev_replace, tgtdev is missing");
891                 btrfs_info(fs_info,
892                            "you may cancel the operation after 'mount -o degraded'");
893                 dev_replace->replace_state =
894                                         BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED;
895                 btrfs_dev_replace_write_unlock(dev_replace);
896                 return 0;
897         }
898         btrfs_dev_replace_write_unlock(dev_replace);
899
900         /*
901          * This could collide with a paused balance, but the exclusive op logic
902          * should never allow both to start and pause. We don't want to allow
903          * dev-replace to start anyway.
904          */
905         if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
906                 btrfs_dev_replace_write_lock(dev_replace);
907                 dev_replace->replace_state =
908                                         BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED;
909                 btrfs_dev_replace_write_unlock(dev_replace);
910                 btrfs_info(fs_info,
911                 "cannot resume dev-replace, other exclusive operation running");
912                 return 0;
913         }
914
915         task = kthread_run(btrfs_dev_replace_kthread, fs_info, "btrfs-devrepl");
916         return PTR_ERR_OR_ZERO(task);
917 }
918
919 static int btrfs_dev_replace_kthread(void *data)
920 {
921         struct btrfs_fs_info *fs_info = data;
922         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
923         u64 progress;
924         int ret;
925
926         progress = btrfs_dev_replace_progress(fs_info);
927         progress = div_u64(progress, 10);
928         btrfs_info_in_rcu(fs_info,
929                 "continuing dev_replace from %s (devid %llu) to target %s @%u%%",
930                 btrfs_dev_name(dev_replace->srcdev),
931                 dev_replace->srcdev->devid,
932                 btrfs_dev_name(dev_replace->tgtdev),
933                 (unsigned int)progress);
934
935         ret = btrfs_scrub_dev(fs_info, dev_replace->srcdev->devid,
936                               dev_replace->committed_cursor_left,
937                               btrfs_device_get_total_bytes(dev_replace->srcdev),
938                               &dev_replace->scrub_progress, 0, 1);
939         ret = btrfs_dev_replace_finishing(fs_info, ret);
940         WARN_ON(ret);
941
942         clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
943         return 0;
944 }
945
946 int btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace)
947 {
948         if (!dev_replace->is_valid)
949                 return 0;
950
951         switch (dev_replace->replace_state) {
952         case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
953         case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
954         case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
955                 return 0;
956         case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
957         case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
958                 /*
959                  * return true even if tgtdev is missing (this is
960                  * something that can happen if the dev_replace
961                  * procedure is suspended by an umount and then
962                  * the tgtdev is missing (or "btrfs dev scan") was
963                  * not called and the the filesystem is remounted
964                  * in degraded state. This does not stop the
965                  * dev_replace procedure. It needs to be canceled
966                  * manually if the cancellation is wanted.
967                  */
968                 break;
969         }
970         return 1;
971 }
972
973 void btrfs_dev_replace_read_lock(struct btrfs_dev_replace *dev_replace)
974 {
975         read_lock(&dev_replace->lock);
976 }
977
978 void btrfs_dev_replace_read_unlock(struct btrfs_dev_replace *dev_replace)
979 {
980         read_unlock(&dev_replace->lock);
981 }
982
983 void btrfs_dev_replace_write_lock(struct btrfs_dev_replace *dev_replace)
984 {
985 again:
986         wait_event(dev_replace->read_lock_wq,
987                    atomic_read(&dev_replace->blocking_readers) == 0);
988         write_lock(&dev_replace->lock);
989         if (atomic_read(&dev_replace->blocking_readers)) {
990                 write_unlock(&dev_replace->lock);
991                 goto again;
992         }
993 }
994
995 void btrfs_dev_replace_write_unlock(struct btrfs_dev_replace *dev_replace)
996 {
997         write_unlock(&dev_replace->lock);
998 }
999
1000 /* inc blocking cnt and release read lock */
1001 void btrfs_dev_replace_set_lock_blocking(
1002                                         struct btrfs_dev_replace *dev_replace)
1003 {
1004         /* only set blocking for read lock */
1005         atomic_inc(&dev_replace->blocking_readers);
1006         read_unlock(&dev_replace->lock);
1007 }
1008
1009 void btrfs_bio_counter_inc_noblocked(struct btrfs_fs_info *fs_info)
1010 {
1011         percpu_counter_inc(&fs_info->dev_replace.bio_counter);
1012 }
1013
1014 void btrfs_bio_counter_sub(struct btrfs_fs_info *fs_info, s64 amount)
1015 {
1016         percpu_counter_sub(&fs_info->dev_replace.bio_counter, amount);
1017         cond_wake_up_nomb(&fs_info->dev_replace.replace_wait);
1018 }
1019
1020 void btrfs_bio_counter_inc_blocked(struct btrfs_fs_info *fs_info)
1021 {
1022         while (1) {
1023                 percpu_counter_inc(&fs_info->dev_replace.bio_counter);
1024                 if (likely(!test_bit(BTRFS_FS_STATE_DEV_REPLACING,
1025                                      &fs_info->fs_state)))
1026                         break;
1027
1028                 btrfs_bio_counter_dec(fs_info);
1029                 wait_event(fs_info->dev_replace.replace_wait,
1030                            !test_bit(BTRFS_FS_STATE_DEV_REPLACING,
1031                                      &fs_info->fs_state));
1032         }
1033 }