ARM: tegra: make device can run on UP
[linux-3.10.git] / fs / btrfs / dev-replace.c
1 /*
2  * Copyright (C) STRATO AG 2012.  All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public
6  * License v2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public
14  * License along with this program; if not, write to the
15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16  * Boston, MA 021110-1307, USA.
17  */
18 #include <linux/sched.h>
19 #include <linux/bio.h>
20 #include <linux/slab.h>
21 #include <linux/buffer_head.h>
22 #include <linux/blkdev.h>
23 #include <linux/random.h>
24 #include <linux/iocontext.h>
25 #include <linux/capability.h>
26 #include <linux/kthread.h>
27 #include <linux/math64.h>
28 #include <asm/div64.h>
29 #include "compat.h"
30 #include "ctree.h"
31 #include "extent_map.h"
32 #include "disk-io.h"
33 #include "transaction.h"
34 #include "print-tree.h"
35 #include "volumes.h"
36 #include "async-thread.h"
37 #include "check-integrity.h"
38 #include "rcu-string.h"
39 #include "dev-replace.h"
40
41 static u64 btrfs_get_seconds_since_1970(void);
42 static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
43                                        int scrub_ret);
44 static void btrfs_dev_replace_update_device_in_mapping_tree(
45                                                 struct btrfs_fs_info *fs_info,
46                                                 struct btrfs_device *srcdev,
47                                                 struct btrfs_device *tgtdev);
48 static int btrfs_dev_replace_find_srcdev(struct btrfs_root *root, u64 srcdevid,
49                                          char *srcdev_name,
50                                          struct btrfs_device **device);
51 static u64 __btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info);
52 static int btrfs_dev_replace_kthread(void *data);
53 static int btrfs_dev_replace_continue_on_mount(struct btrfs_fs_info *fs_info);
54
55
56 int btrfs_init_dev_replace(struct btrfs_fs_info *fs_info)
57 {
58         struct btrfs_key key;
59         struct btrfs_root *dev_root = fs_info->dev_root;
60         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
61         struct extent_buffer *eb;
62         int slot;
63         int ret = 0;
64         struct btrfs_path *path = NULL;
65         int item_size;
66         struct btrfs_dev_replace_item *ptr;
67         u64 src_devid;
68
69         path = btrfs_alloc_path();
70         if (!path) {
71                 ret = -ENOMEM;
72                 goto out;
73         }
74
75         key.objectid = 0;
76         key.type = BTRFS_DEV_REPLACE_KEY;
77         key.offset = 0;
78         ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
79         if (ret) {
80 no_valid_dev_replace_entry_found:
81                 ret = 0;
82                 dev_replace->replace_state =
83                         BTRFS_DEV_REPLACE_ITEM_STATE_NEVER_STARTED;
84                 dev_replace->cont_reading_from_srcdev_mode =
85                     BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_ALWAYS;
86                 dev_replace->replace_state = 0;
87                 dev_replace->time_started = 0;
88                 dev_replace->time_stopped = 0;
89                 atomic64_set(&dev_replace->num_write_errors, 0);
90                 atomic64_set(&dev_replace->num_uncorrectable_read_errors, 0);
91                 dev_replace->cursor_left = 0;
92                 dev_replace->committed_cursor_left = 0;
93                 dev_replace->cursor_left_last_write_of_item = 0;
94                 dev_replace->cursor_right = 0;
95                 dev_replace->srcdev = NULL;
96                 dev_replace->tgtdev = NULL;
97                 dev_replace->is_valid = 0;
98                 dev_replace->item_needs_writeback = 0;
99                 goto out;
100         }
101         slot = path->slots[0];
102         eb = path->nodes[0];
103         item_size = btrfs_item_size_nr(eb, slot);
104         ptr = btrfs_item_ptr(eb, slot, struct btrfs_dev_replace_item);
105
106         if (item_size != sizeof(struct btrfs_dev_replace_item)) {
107                 pr_warn("btrfs: dev_replace entry found has unexpected size, ignore entry\n");
108                 goto no_valid_dev_replace_entry_found;
109         }
110
111         src_devid = btrfs_dev_replace_src_devid(eb, ptr);
112         dev_replace->cont_reading_from_srcdev_mode =
113                 btrfs_dev_replace_cont_reading_from_srcdev_mode(eb, ptr);
114         dev_replace->replace_state = btrfs_dev_replace_replace_state(eb, ptr);
115         dev_replace->time_started = btrfs_dev_replace_time_started(eb, ptr);
116         dev_replace->time_stopped =
117                 btrfs_dev_replace_time_stopped(eb, ptr);
118         atomic64_set(&dev_replace->num_write_errors,
119                      btrfs_dev_replace_num_write_errors(eb, ptr));
120         atomic64_set(&dev_replace->num_uncorrectable_read_errors,
121                      btrfs_dev_replace_num_uncorrectable_read_errors(eb, ptr));
122         dev_replace->cursor_left = btrfs_dev_replace_cursor_left(eb, ptr);
123         dev_replace->committed_cursor_left = dev_replace->cursor_left;
124         dev_replace->cursor_left_last_write_of_item = dev_replace->cursor_left;
125         dev_replace->cursor_right = btrfs_dev_replace_cursor_right(eb, ptr);
126         dev_replace->is_valid = 1;
127
128         dev_replace->item_needs_writeback = 0;
129         switch (dev_replace->replace_state) {
130         case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
131         case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
132         case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
133                 dev_replace->srcdev = NULL;
134                 dev_replace->tgtdev = NULL;
135                 break;
136         case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
137         case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
138                 dev_replace->srcdev = btrfs_find_device(fs_info, src_devid,
139                                                         NULL, NULL);
140                 dev_replace->tgtdev = btrfs_find_device(fs_info,
141                                                         BTRFS_DEV_REPLACE_DEVID,
142                                                         NULL, NULL);
143                 /*
144                  * allow 'btrfs dev replace_cancel' if src/tgt device is
145                  * missing
146                  */
147                 if (!dev_replace->srcdev &&
148                     !btrfs_test_opt(dev_root, DEGRADED)) {
149                         ret = -EIO;
150                         pr_warn("btrfs: cannot mount because device replace operation is ongoing and\n" "srcdev (devid %llu) is missing, need to run 'btrfs dev scan'?\n",
151                                 (unsigned long long)src_devid);
152                 }
153                 if (!dev_replace->tgtdev &&
154                     !btrfs_test_opt(dev_root, DEGRADED)) {
155                         ret = -EIO;
156                         pr_warn("btrfs: cannot mount because device replace operation is ongoing and\n" "tgtdev (devid %llu) is missing, need to run btrfs dev scan?\n",
157                                 (unsigned long long)BTRFS_DEV_REPLACE_DEVID);
158                 }
159                 if (dev_replace->tgtdev) {
160                         if (dev_replace->srcdev) {
161                                 dev_replace->tgtdev->total_bytes =
162                                         dev_replace->srcdev->total_bytes;
163                                 dev_replace->tgtdev->disk_total_bytes =
164                                         dev_replace->srcdev->disk_total_bytes;
165                                 dev_replace->tgtdev->bytes_used =
166                                         dev_replace->srcdev->bytes_used;
167                         }
168                         dev_replace->tgtdev->is_tgtdev_for_dev_replace = 1;
169                         btrfs_init_dev_replace_tgtdev_for_resume(fs_info,
170                                 dev_replace->tgtdev);
171                 }
172                 break;
173         }
174
175 out:
176         if (path)
177                 btrfs_free_path(path);
178         return ret;
179 }
180
181 /*
182  * called from commit_transaction. Writes changed device replace state to
183  * disk.
184  */
185 int btrfs_run_dev_replace(struct btrfs_trans_handle *trans,
186                           struct btrfs_fs_info *fs_info)
187 {
188         int ret;
189         struct btrfs_root *dev_root = fs_info->dev_root;
190         struct btrfs_path *path;
191         struct btrfs_key key;
192         struct extent_buffer *eb;
193         struct btrfs_dev_replace_item *ptr;
194         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
195
196         btrfs_dev_replace_lock(dev_replace);
197         if (!dev_replace->is_valid ||
198             !dev_replace->item_needs_writeback) {
199                 btrfs_dev_replace_unlock(dev_replace);
200                 return 0;
201         }
202         btrfs_dev_replace_unlock(dev_replace);
203
204         key.objectid = 0;
205         key.type = BTRFS_DEV_REPLACE_KEY;
206         key.offset = 0;
207
208         path = btrfs_alloc_path();
209         if (!path) {
210                 ret = -ENOMEM;
211                 goto out;
212         }
213         ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
214         if (ret < 0) {
215                 pr_warn("btrfs: error %d while searching for dev_replace item!\n",
216                         ret);
217                 goto out;
218         }
219
220         if (ret == 0 &&
221             btrfs_item_size_nr(path->nodes[0], path->slots[0]) < sizeof(*ptr)) {
222                 /*
223                  * need to delete old one and insert a new one.
224                  * Since no attempt is made to recover any old state, if the
225                  * dev_replace state is 'running', the data on the target
226                  * drive is lost.
227                  * It would be possible to recover the state: just make sure
228                  * that the beginning of the item is never changed and always
229                  * contains all the essential information. Then read this
230                  * minimal set of information and use it as a base for the
231                  * new state.
232                  */
233                 ret = btrfs_del_item(trans, dev_root, path);
234                 if (ret != 0) {
235                         pr_warn("btrfs: delete too small dev_replace item failed %d!\n",
236                                 ret);
237                         goto out;
238                 }
239                 ret = 1;
240         }
241
242         if (ret == 1) {
243                 /* need to insert a new item */
244                 btrfs_release_path(path);
245                 ret = btrfs_insert_empty_item(trans, dev_root, path,
246                                               &key, sizeof(*ptr));
247                 if (ret < 0) {
248                         pr_warn("btrfs: insert dev_replace item failed %d!\n",
249                                 ret);
250                         goto out;
251                 }
252         }
253
254         eb = path->nodes[0];
255         ptr = btrfs_item_ptr(eb, path->slots[0],
256                              struct btrfs_dev_replace_item);
257
258         btrfs_dev_replace_lock(dev_replace);
259         if (dev_replace->srcdev)
260                 btrfs_set_dev_replace_src_devid(eb, ptr,
261                         dev_replace->srcdev->devid);
262         else
263                 btrfs_set_dev_replace_src_devid(eb, ptr, (u64)-1);
264         btrfs_set_dev_replace_cont_reading_from_srcdev_mode(eb, ptr,
265                 dev_replace->cont_reading_from_srcdev_mode);
266         btrfs_set_dev_replace_replace_state(eb, ptr,
267                 dev_replace->replace_state);
268         btrfs_set_dev_replace_time_started(eb, ptr, dev_replace->time_started);
269         btrfs_set_dev_replace_time_stopped(eb, ptr, dev_replace->time_stopped);
270         btrfs_set_dev_replace_num_write_errors(eb, ptr,
271                 atomic64_read(&dev_replace->num_write_errors));
272         btrfs_set_dev_replace_num_uncorrectable_read_errors(eb, ptr,
273                 atomic64_read(&dev_replace->num_uncorrectable_read_errors));
274         dev_replace->cursor_left_last_write_of_item =
275                 dev_replace->cursor_left;
276         btrfs_set_dev_replace_cursor_left(eb, ptr,
277                 dev_replace->cursor_left_last_write_of_item);
278         btrfs_set_dev_replace_cursor_right(eb, ptr,
279                 dev_replace->cursor_right);
280         dev_replace->item_needs_writeback = 0;
281         btrfs_dev_replace_unlock(dev_replace);
282
283         btrfs_mark_buffer_dirty(eb);
284
285 out:
286         btrfs_free_path(path);
287
288         return ret;
289 }
290
291 void btrfs_after_dev_replace_commit(struct btrfs_fs_info *fs_info)
292 {
293         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
294
295         dev_replace->committed_cursor_left =
296                 dev_replace->cursor_left_last_write_of_item;
297 }
298
299 static u64 btrfs_get_seconds_since_1970(void)
300 {
301         struct timespec t = CURRENT_TIME_SEC;
302
303         return t.tv_sec;
304 }
305
306 int btrfs_dev_replace_start(struct btrfs_root *root,
307                             struct btrfs_ioctl_dev_replace_args *args)
308 {
309         struct btrfs_trans_handle *trans;
310         struct btrfs_fs_info *fs_info = root->fs_info;
311         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
312         int ret;
313         struct btrfs_device *tgt_device = NULL;
314         struct btrfs_device *src_device = NULL;
315
316         switch (args->start.cont_reading_from_srcdev_mode) {
317         case BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_ALWAYS:
318         case BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_AVOID:
319                 break;
320         default:
321                 return -EINVAL;
322         }
323
324         if ((args->start.srcdevid == 0 && args->start.srcdev_name[0] == '\0') ||
325             args->start.tgtdev_name[0] == '\0')
326                 return -EINVAL;
327
328         mutex_lock(&fs_info->volume_mutex);
329         ret = btrfs_init_dev_replace_tgtdev(root, args->start.tgtdev_name,
330                                             &tgt_device);
331         if (ret) {
332                 pr_err("btrfs: target device %s is invalid!\n",
333                        args->start.tgtdev_name);
334                 mutex_unlock(&fs_info->volume_mutex);
335                 return -EINVAL;
336         }
337
338         ret = btrfs_dev_replace_find_srcdev(root, args->start.srcdevid,
339                                             args->start.srcdev_name,
340                                             &src_device);
341         mutex_unlock(&fs_info->volume_mutex);
342         if (ret) {
343                 ret = -EINVAL;
344                 goto leave_no_lock;
345         }
346
347         if (tgt_device->total_bytes < src_device->total_bytes) {
348                 pr_err("btrfs: target device is smaller than source device!\n");
349                 ret = -EINVAL;
350                 goto leave_no_lock;
351         }
352
353         btrfs_dev_replace_lock(dev_replace);
354         switch (dev_replace->replace_state) {
355         case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
356         case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
357         case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
358                 break;
359         case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
360         case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
361                 args->result = BTRFS_IOCTL_DEV_REPLACE_RESULT_ALREADY_STARTED;
362                 goto leave;
363         }
364
365         dev_replace->cont_reading_from_srcdev_mode =
366                 args->start.cont_reading_from_srcdev_mode;
367         WARN_ON(!src_device);
368         dev_replace->srcdev = src_device;
369         WARN_ON(!tgt_device);
370         dev_replace->tgtdev = tgt_device;
371
372         printk_in_rcu(KERN_INFO
373                       "btrfs: dev_replace from %s (devid %llu) to %s) started\n",
374                       src_device->missing ? "<missing disk>" :
375                         rcu_str_deref(src_device->name),
376                       src_device->devid,
377                       rcu_str_deref(tgt_device->name));
378
379         tgt_device->total_bytes = src_device->total_bytes;
380         tgt_device->disk_total_bytes = src_device->disk_total_bytes;
381         tgt_device->bytes_used = src_device->bytes_used;
382
383         /*
384          * from now on, the writes to the srcdev are all duplicated to
385          * go to the tgtdev as well (refer to btrfs_map_block()).
386          */
387         dev_replace->replace_state = BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED;
388         dev_replace->time_started = btrfs_get_seconds_since_1970();
389         dev_replace->cursor_left = 0;
390         dev_replace->committed_cursor_left = 0;
391         dev_replace->cursor_left_last_write_of_item = 0;
392         dev_replace->cursor_right = 0;
393         dev_replace->is_valid = 1;
394         dev_replace->item_needs_writeback = 1;
395         args->result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR;
396         btrfs_dev_replace_unlock(dev_replace);
397
398         btrfs_wait_ordered_extents(root, 0);
399
400         /* force writing the updated state information to disk */
401         trans = btrfs_start_transaction(root, 0);
402         if (IS_ERR(trans)) {
403                 ret = PTR_ERR(trans);
404                 btrfs_dev_replace_lock(dev_replace);
405                 goto leave;
406         }
407
408         ret = btrfs_commit_transaction(trans, root);
409         WARN_ON(ret);
410
411         /* the disk copy procedure reuses the scrub code */
412         ret = btrfs_scrub_dev(fs_info, src_device->devid, 0,
413                               src_device->total_bytes,
414                               &dev_replace->scrub_progress, 0, 1);
415
416         ret = btrfs_dev_replace_finishing(root->fs_info, ret);
417         WARN_ON(ret);
418
419         return 0;
420
421 leave:
422         dev_replace->srcdev = NULL;
423         dev_replace->tgtdev = NULL;
424         btrfs_dev_replace_unlock(dev_replace);
425 leave_no_lock:
426         if (tgt_device)
427                 btrfs_destroy_dev_replace_tgtdev(fs_info, tgt_device);
428         return ret;
429 }
430
431 static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
432                                        int scrub_ret)
433 {
434         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
435         struct btrfs_device *tgt_device;
436         struct btrfs_device *src_device;
437         struct btrfs_root *root = fs_info->tree_root;
438         u8 uuid_tmp[BTRFS_UUID_SIZE];
439         struct btrfs_trans_handle *trans;
440         int ret = 0;
441
442         /* don't allow cancel or unmount to disturb the finishing procedure */
443         mutex_lock(&dev_replace->lock_finishing_cancel_unmount);
444
445         btrfs_dev_replace_lock(dev_replace);
446         /* was the operation canceled, or is it finished? */
447         if (dev_replace->replace_state !=
448             BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED) {
449                 btrfs_dev_replace_unlock(dev_replace);
450                 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
451                 return 0;
452         }
453
454         tgt_device = dev_replace->tgtdev;
455         src_device = dev_replace->srcdev;
456         btrfs_dev_replace_unlock(dev_replace);
457
458         /* replace old device with new one in mapping tree */
459         if (!scrub_ret)
460                 btrfs_dev_replace_update_device_in_mapping_tree(fs_info,
461                                                                 src_device,
462                                                                 tgt_device);
463
464         /*
465          * flush all outstanding I/O and inode extent mappings before the
466          * copy operation is declared as being finished
467          */
468         btrfs_start_delalloc_inodes(root, 0);
469         btrfs_wait_ordered_extents(root, 0);
470
471         trans = btrfs_start_transaction(root, 0);
472         if (IS_ERR(trans)) {
473                 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
474                 return PTR_ERR(trans);
475         }
476         ret = btrfs_commit_transaction(trans, root);
477         WARN_ON(ret);
478
479         /* keep away write_all_supers() during the finishing procedure */
480         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
481         btrfs_dev_replace_lock(dev_replace);
482         dev_replace->replace_state =
483                 scrub_ret ? BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED
484                           : BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED;
485         dev_replace->tgtdev = NULL;
486         dev_replace->srcdev = NULL;
487         dev_replace->time_stopped = btrfs_get_seconds_since_1970();
488         dev_replace->item_needs_writeback = 1;
489
490         if (scrub_ret) {
491                 printk_in_rcu(KERN_ERR
492                               "btrfs: btrfs_scrub_dev(%s, %llu, %s) failed %d\n",
493                               src_device->missing ? "<missing disk>" :
494                                 rcu_str_deref(src_device->name),
495                               src_device->devid,
496                               rcu_str_deref(tgt_device->name), scrub_ret);
497                 btrfs_dev_replace_unlock(dev_replace);
498                 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
499                 if (tgt_device)
500                         btrfs_destroy_dev_replace_tgtdev(fs_info, tgt_device);
501                 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
502
503                 return 0;
504         }
505
506         printk_in_rcu(KERN_INFO
507                       "btrfs: dev_replace from %s (devid %llu) to %s) finished\n",
508                       src_device->missing ? "<missing disk>" :
509                         rcu_str_deref(src_device->name),
510                       src_device->devid,
511                       rcu_str_deref(tgt_device->name));
512         tgt_device->is_tgtdev_for_dev_replace = 0;
513         tgt_device->devid = src_device->devid;
514         src_device->devid = BTRFS_DEV_REPLACE_DEVID;
515         tgt_device->bytes_used = src_device->bytes_used;
516         memcpy(uuid_tmp, tgt_device->uuid, sizeof(uuid_tmp));
517         memcpy(tgt_device->uuid, src_device->uuid, sizeof(tgt_device->uuid));
518         memcpy(src_device->uuid, uuid_tmp, sizeof(src_device->uuid));
519         tgt_device->total_bytes = src_device->total_bytes;
520         tgt_device->disk_total_bytes = src_device->disk_total_bytes;
521         tgt_device->bytes_used = src_device->bytes_used;
522         if (fs_info->sb->s_bdev == src_device->bdev)
523                 fs_info->sb->s_bdev = tgt_device->bdev;
524         if (fs_info->fs_devices->latest_bdev == src_device->bdev)
525                 fs_info->fs_devices->latest_bdev = tgt_device->bdev;
526         list_add(&tgt_device->dev_alloc_list, &fs_info->fs_devices->alloc_list);
527
528         btrfs_rm_dev_replace_srcdev(fs_info, src_device);
529         if (src_device->bdev) {
530                 /* zero out the old super */
531                 btrfs_scratch_superblock(src_device);
532         }
533         /*
534          * this is again a consistent state where no dev_replace procedure
535          * is running, the target device is part of the filesystem, the
536          * source device is not part of the filesystem anymore and its 1st
537          * superblock is scratched out so that it is no longer marked to
538          * belong to this filesystem.
539          */
540         btrfs_dev_replace_unlock(dev_replace);
541         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
542
543         /* write back the superblocks */
544         trans = btrfs_start_transaction(root, 0);
545         if (!IS_ERR(trans))
546                 btrfs_commit_transaction(trans, root);
547
548         mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
549
550         return 0;
551 }
552
553 static void btrfs_dev_replace_update_device_in_mapping_tree(
554                                                 struct btrfs_fs_info *fs_info,
555                                                 struct btrfs_device *srcdev,
556                                                 struct btrfs_device *tgtdev)
557 {
558         struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
559         struct extent_map *em;
560         struct map_lookup *map;
561         u64 start = 0;
562         int i;
563
564         write_lock(&em_tree->lock);
565         do {
566                 em = lookup_extent_mapping(em_tree, start, (u64)-1);
567                 if (!em)
568                         break;
569                 map = (struct map_lookup *)em->bdev;
570                 for (i = 0; i < map->num_stripes; i++)
571                         if (srcdev == map->stripes[i].dev)
572                                 map->stripes[i].dev = tgtdev;
573                 start = em->start + em->len;
574                 free_extent_map(em);
575         } while (start);
576         write_unlock(&em_tree->lock);
577 }
578
579 static int btrfs_dev_replace_find_srcdev(struct btrfs_root *root, u64 srcdevid,
580                                          char *srcdev_name,
581                                          struct btrfs_device **device)
582 {
583         int ret;
584
585         if (srcdevid) {
586                 ret = 0;
587                 *device = btrfs_find_device(root->fs_info, srcdevid, NULL,
588                                             NULL);
589                 if (!*device)
590                         ret = -ENOENT;
591         } else {
592                 ret = btrfs_find_device_missing_or_by_path(root, srcdev_name,
593                                                            device);
594         }
595         return ret;
596 }
597
598 void btrfs_dev_replace_status(struct btrfs_fs_info *fs_info,
599                               struct btrfs_ioctl_dev_replace_args *args)
600 {
601         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
602
603         btrfs_dev_replace_lock(dev_replace);
604         /* even if !dev_replace_is_valid, the values are good enough for
605          * the replace_status ioctl */
606         args->result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR;
607         args->status.replace_state = dev_replace->replace_state;
608         args->status.time_started = dev_replace->time_started;
609         args->status.time_stopped = dev_replace->time_stopped;
610         args->status.num_write_errors =
611                 atomic64_read(&dev_replace->num_write_errors);
612         args->status.num_uncorrectable_read_errors =
613                 atomic64_read(&dev_replace->num_uncorrectable_read_errors);
614         switch (dev_replace->replace_state) {
615         case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
616         case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
617                 args->status.progress_1000 = 0;
618                 break;
619         case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
620                 args->status.progress_1000 = 1000;
621                 break;
622         case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
623         case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
624                 args->status.progress_1000 = div64_u64(dev_replace->cursor_left,
625                         div64_u64(dev_replace->srcdev->total_bytes, 1000));
626                 break;
627         }
628         btrfs_dev_replace_unlock(dev_replace);
629 }
630
631 int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info,
632                              struct btrfs_ioctl_dev_replace_args *args)
633 {
634         args->result = __btrfs_dev_replace_cancel(fs_info);
635         return 0;
636 }
637
638 static u64 __btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info)
639 {
640         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
641         struct btrfs_device *tgt_device = NULL;
642         struct btrfs_trans_handle *trans;
643         struct btrfs_root *root = fs_info->tree_root;
644         u64 result;
645         int ret;
646
647         mutex_lock(&dev_replace->lock_finishing_cancel_unmount);
648         btrfs_dev_replace_lock(dev_replace);
649         switch (dev_replace->replace_state) {
650         case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
651         case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
652         case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
653                 result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NOT_STARTED;
654                 btrfs_dev_replace_unlock(dev_replace);
655                 goto leave;
656         case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
657         case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
658                 result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR;
659                 tgt_device = dev_replace->tgtdev;
660                 dev_replace->tgtdev = NULL;
661                 dev_replace->srcdev = NULL;
662                 break;
663         }
664         dev_replace->replace_state = BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED;
665         dev_replace->time_stopped = btrfs_get_seconds_since_1970();
666         dev_replace->item_needs_writeback = 1;
667         btrfs_dev_replace_unlock(dev_replace);
668         btrfs_scrub_cancel(fs_info);
669
670         trans = btrfs_start_transaction(root, 0);
671         if (IS_ERR(trans)) {
672                 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
673                 return PTR_ERR(trans);
674         }
675         ret = btrfs_commit_transaction(trans, root);
676         WARN_ON(ret);
677         if (tgt_device)
678                 btrfs_destroy_dev_replace_tgtdev(fs_info, tgt_device);
679
680 leave:
681         mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
682         return result;
683 }
684
685 void btrfs_dev_replace_suspend_for_unmount(struct btrfs_fs_info *fs_info)
686 {
687         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
688
689         mutex_lock(&dev_replace->lock_finishing_cancel_unmount);
690         btrfs_dev_replace_lock(dev_replace);
691         switch (dev_replace->replace_state) {
692         case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
693         case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
694         case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
695         case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
696                 break;
697         case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
698                 dev_replace->replace_state =
699                         BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED;
700                 dev_replace->time_stopped = btrfs_get_seconds_since_1970();
701                 dev_replace->item_needs_writeback = 1;
702                 pr_info("btrfs: suspending dev_replace for unmount\n");
703                 break;
704         }
705
706         btrfs_dev_replace_unlock(dev_replace);
707         mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
708 }
709
710 /* resume dev_replace procedure that was interrupted by unmount */
711 int btrfs_resume_dev_replace_async(struct btrfs_fs_info *fs_info)
712 {
713         struct task_struct *task;
714         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
715
716         btrfs_dev_replace_lock(dev_replace);
717         switch (dev_replace->replace_state) {
718         case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
719         case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
720         case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
721                 btrfs_dev_replace_unlock(dev_replace);
722                 return 0;
723         case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
724                 break;
725         case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
726                 dev_replace->replace_state =
727                         BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED;
728                 break;
729         }
730         if (!dev_replace->tgtdev || !dev_replace->tgtdev->bdev) {
731                 pr_info("btrfs: cannot continue dev_replace, tgtdev is missing\n"
732                         "btrfs: you may cancel the operation after 'mount -o degraded'\n");
733                 btrfs_dev_replace_unlock(dev_replace);
734                 return 0;
735         }
736         btrfs_dev_replace_unlock(dev_replace);
737
738         WARN_ON(atomic_xchg(
739                 &fs_info->mutually_exclusive_operation_running, 1));
740         task = kthread_run(btrfs_dev_replace_kthread, fs_info, "btrfs-devrepl");
741         return PTR_RET(task);
742 }
743
744 static int btrfs_dev_replace_kthread(void *data)
745 {
746         struct btrfs_fs_info *fs_info = data;
747         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
748         struct btrfs_ioctl_dev_replace_args *status_args;
749         u64 progress;
750
751         status_args = kzalloc(sizeof(*status_args), GFP_NOFS);
752         if (status_args) {
753                 btrfs_dev_replace_status(fs_info, status_args);
754                 progress = status_args->status.progress_1000;
755                 kfree(status_args);
756                 do_div(progress, 10);
757                 printk_in_rcu(KERN_INFO
758                               "btrfs: continuing dev_replace from %s (devid %llu) to %s @%u%%\n",
759                               dev_replace->srcdev->missing ? "<missing disk>" :
760                                 rcu_str_deref(dev_replace->srcdev->name),
761                               dev_replace->srcdev->devid,
762                               dev_replace->tgtdev ?
763                                 rcu_str_deref(dev_replace->tgtdev->name) :
764                                 "<missing target disk>",
765                               (unsigned int)progress);
766         }
767         btrfs_dev_replace_continue_on_mount(fs_info);
768         atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
769
770         return 0;
771 }
772
773 static int btrfs_dev_replace_continue_on_mount(struct btrfs_fs_info *fs_info)
774 {
775         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
776         int ret;
777
778         ret = btrfs_scrub_dev(fs_info, dev_replace->srcdev->devid,
779                               dev_replace->committed_cursor_left,
780                               dev_replace->srcdev->total_bytes,
781                               &dev_replace->scrub_progress, 0, 1);
782         ret = btrfs_dev_replace_finishing(fs_info, ret);
783         WARN_ON(ret);
784         return 0;
785 }
786
787 int btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace)
788 {
789         if (!dev_replace->is_valid)
790                 return 0;
791
792         switch (dev_replace->replace_state) {
793         case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
794         case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
795         case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
796                 return 0;
797         case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
798         case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
799                 /*
800                  * return true even if tgtdev is missing (this is
801                  * something that can happen if the dev_replace
802                  * procedure is suspended by an umount and then
803                  * the tgtdev is missing (or "btrfs dev scan") was
804                  * not called and the the filesystem is remounted
805                  * in degraded state. This does not stop the
806                  * dev_replace procedure. It needs to be canceled
807                  * manually if the cancelation is wanted.
808                  */
809                 break;
810         }
811         return 1;
812 }
813
814 void btrfs_dev_replace_lock(struct btrfs_dev_replace *dev_replace)
815 {
816         /* the beginning is just an optimization for the typical case */
817         if (atomic_read(&dev_replace->nesting_level) == 0) {
818 acquire_lock:
819                 /* this is not a nested case where the same thread
820                  * is trying to acqurire the same lock twice */
821                 mutex_lock(&dev_replace->lock);
822                 mutex_lock(&dev_replace->lock_management_lock);
823                 dev_replace->lock_owner = current->pid;
824                 atomic_inc(&dev_replace->nesting_level);
825                 mutex_unlock(&dev_replace->lock_management_lock);
826                 return;
827         }
828
829         mutex_lock(&dev_replace->lock_management_lock);
830         if (atomic_read(&dev_replace->nesting_level) > 0 &&
831             dev_replace->lock_owner == current->pid) {
832                 WARN_ON(!mutex_is_locked(&dev_replace->lock));
833                 atomic_inc(&dev_replace->nesting_level);
834                 mutex_unlock(&dev_replace->lock_management_lock);
835                 return;
836         }
837
838         mutex_unlock(&dev_replace->lock_management_lock);
839         goto acquire_lock;
840 }
841
842 void btrfs_dev_replace_unlock(struct btrfs_dev_replace *dev_replace)
843 {
844         WARN_ON(!mutex_is_locked(&dev_replace->lock));
845         mutex_lock(&dev_replace->lock_management_lock);
846         WARN_ON(atomic_read(&dev_replace->nesting_level) < 1);
847         WARN_ON(dev_replace->lock_owner != current->pid);
848         atomic_dec(&dev_replace->nesting_level);
849         if (atomic_read(&dev_replace->nesting_level) == 0) {
850                 dev_replace->lock_owner = 0;
851                 mutex_unlock(&dev_replace->lock_management_lock);
852                 mutex_unlock(&dev_replace->lock);
853         } else {
854                 mutex_unlock(&dev_replace->lock_management_lock);
855         }
856 }