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Btrfs: fix a build warning for an unused label
[~shefty/rdma-dev.git] / fs / btrfs / volumes.c
1 /*
2  * Copyright (C) 2007 Oracle.  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/ratelimit.h>
27 #include <linux/kthread.h>
28 #include "compat.h"
29 #include "ctree.h"
30 #include "extent_map.h"
31 #include "disk-io.h"
32 #include "transaction.h"
33 #include "print-tree.h"
34 #include "volumes.h"
35 #include "async-thread.h"
36 #include "check-integrity.h"
37 #include "rcu-string.h"
38 #include "math.h"
39 #include "dev-replace.h"
40
41 static int init_first_rw_device(struct btrfs_trans_handle *trans,
42                                 struct btrfs_root *root,
43                                 struct btrfs_device *device);
44 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
45 static void __btrfs_reset_dev_stats(struct btrfs_device *dev);
46 static void btrfs_dev_stat_print_on_load(struct btrfs_device *device);
47
48 static DEFINE_MUTEX(uuid_mutex);
49 static LIST_HEAD(fs_uuids);
50
51 static void lock_chunks(struct btrfs_root *root)
52 {
53         mutex_lock(&root->fs_info->chunk_mutex);
54 }
55
56 static void unlock_chunks(struct btrfs_root *root)
57 {
58         mutex_unlock(&root->fs_info->chunk_mutex);
59 }
60
61 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
62 {
63         struct btrfs_device *device;
64         WARN_ON(fs_devices->opened);
65         while (!list_empty(&fs_devices->devices)) {
66                 device = list_entry(fs_devices->devices.next,
67                                     struct btrfs_device, dev_list);
68                 list_del(&device->dev_list);
69                 rcu_string_free(device->name);
70                 kfree(device);
71         }
72         kfree(fs_devices);
73 }
74
75 void btrfs_cleanup_fs_uuids(void)
76 {
77         struct btrfs_fs_devices *fs_devices;
78
79         while (!list_empty(&fs_uuids)) {
80                 fs_devices = list_entry(fs_uuids.next,
81                                         struct btrfs_fs_devices, list);
82                 list_del(&fs_devices->list);
83                 free_fs_devices(fs_devices);
84         }
85 }
86
87 static noinline struct btrfs_device *__find_device(struct list_head *head,
88                                                    u64 devid, u8 *uuid)
89 {
90         struct btrfs_device *dev;
91
92         list_for_each_entry(dev, head, dev_list) {
93                 if (dev->devid == devid &&
94                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
95                         return dev;
96                 }
97         }
98         return NULL;
99 }
100
101 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
102 {
103         struct btrfs_fs_devices *fs_devices;
104
105         list_for_each_entry(fs_devices, &fs_uuids, list) {
106                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
107                         return fs_devices;
108         }
109         return NULL;
110 }
111
112 static int
113 btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder,
114                       int flush, struct block_device **bdev,
115                       struct buffer_head **bh)
116 {
117         int ret;
118
119         *bdev = blkdev_get_by_path(device_path, flags, holder);
120
121         if (IS_ERR(*bdev)) {
122                 ret = PTR_ERR(*bdev);
123                 printk(KERN_INFO "btrfs: open %s failed\n", device_path);
124                 goto error;
125         }
126
127         if (flush)
128                 filemap_write_and_wait((*bdev)->bd_inode->i_mapping);
129         ret = set_blocksize(*bdev, 4096);
130         if (ret) {
131                 blkdev_put(*bdev, flags);
132                 goto error;
133         }
134         invalidate_bdev(*bdev);
135         *bh = btrfs_read_dev_super(*bdev);
136         if (!*bh) {
137                 ret = -EINVAL;
138                 blkdev_put(*bdev, flags);
139                 goto error;
140         }
141
142         return 0;
143
144 error:
145         *bdev = NULL;
146         *bh = NULL;
147         return ret;
148 }
149
150 static void requeue_list(struct btrfs_pending_bios *pending_bios,
151                         struct bio *head, struct bio *tail)
152 {
153
154         struct bio *old_head;
155
156         old_head = pending_bios->head;
157         pending_bios->head = head;
158         if (pending_bios->tail)
159                 tail->bi_next = old_head;
160         else
161                 pending_bios->tail = tail;
162 }
163
164 /*
165  * we try to collect pending bios for a device so we don't get a large
166  * number of procs sending bios down to the same device.  This greatly
167  * improves the schedulers ability to collect and merge the bios.
168  *
169  * But, it also turns into a long list of bios to process and that is sure
170  * to eventually make the worker thread block.  The solution here is to
171  * make some progress and then put this work struct back at the end of
172  * the list if the block device is congested.  This way, multiple devices
173  * can make progress from a single worker thread.
174  */
175 static noinline void run_scheduled_bios(struct btrfs_device *device)
176 {
177         struct bio *pending;
178         struct backing_dev_info *bdi;
179         struct btrfs_fs_info *fs_info;
180         struct btrfs_pending_bios *pending_bios;
181         struct bio *tail;
182         struct bio *cur;
183         int again = 0;
184         unsigned long num_run;
185         unsigned long batch_run = 0;
186         unsigned long limit;
187         unsigned long last_waited = 0;
188         int force_reg = 0;
189         int sync_pending = 0;
190         struct blk_plug plug;
191
192         /*
193          * this function runs all the bios we've collected for
194          * a particular device.  We don't want to wander off to
195          * another device without first sending all of these down.
196          * So, setup a plug here and finish it off before we return
197          */
198         blk_start_plug(&plug);
199
200         bdi = blk_get_backing_dev_info(device->bdev);
201         fs_info = device->dev_root->fs_info;
202         limit = btrfs_async_submit_limit(fs_info);
203         limit = limit * 2 / 3;
204
205 loop:
206         spin_lock(&device->io_lock);
207
208 loop_lock:
209         num_run = 0;
210
211         /* take all the bios off the list at once and process them
212          * later on (without the lock held).  But, remember the
213          * tail and other pointers so the bios can be properly reinserted
214          * into the list if we hit congestion
215          */
216         if (!force_reg && device->pending_sync_bios.head) {
217                 pending_bios = &device->pending_sync_bios;
218                 force_reg = 1;
219         } else {
220                 pending_bios = &device->pending_bios;
221                 force_reg = 0;
222         }
223
224         pending = pending_bios->head;
225         tail = pending_bios->tail;
226         WARN_ON(pending && !tail);
227
228         /*
229          * if pending was null this time around, no bios need processing
230          * at all and we can stop.  Otherwise it'll loop back up again
231          * and do an additional check so no bios are missed.
232          *
233          * device->running_pending is used to synchronize with the
234          * schedule_bio code.
235          */
236         if (device->pending_sync_bios.head == NULL &&
237             device->pending_bios.head == NULL) {
238                 again = 0;
239                 device->running_pending = 0;
240         } else {
241                 again = 1;
242                 device->running_pending = 1;
243         }
244
245         pending_bios->head = NULL;
246         pending_bios->tail = NULL;
247
248         spin_unlock(&device->io_lock);
249
250         while (pending) {
251
252                 rmb();
253                 /* we want to work on both lists, but do more bios on the
254                  * sync list than the regular list
255                  */
256                 if ((num_run > 32 &&
257                     pending_bios != &device->pending_sync_bios &&
258                     device->pending_sync_bios.head) ||
259                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
260                     device->pending_bios.head)) {
261                         spin_lock(&device->io_lock);
262                         requeue_list(pending_bios, pending, tail);
263                         goto loop_lock;
264                 }
265
266                 cur = pending;
267                 pending = pending->bi_next;
268                 cur->bi_next = NULL;
269
270                 if (atomic_dec_return(&fs_info->nr_async_bios) < limit &&
271                     waitqueue_active(&fs_info->async_submit_wait))
272                         wake_up(&fs_info->async_submit_wait);
273
274                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
275
276                 /*
277                  * if we're doing the sync list, record that our
278                  * plug has some sync requests on it
279                  *
280                  * If we're doing the regular list and there are
281                  * sync requests sitting around, unplug before
282                  * we add more
283                  */
284                 if (pending_bios == &device->pending_sync_bios) {
285                         sync_pending = 1;
286                 } else if (sync_pending) {
287                         blk_finish_plug(&plug);
288                         blk_start_plug(&plug);
289                         sync_pending = 0;
290                 }
291
292                 btrfsic_submit_bio(cur->bi_rw, cur);
293                 num_run++;
294                 batch_run++;
295                 if (need_resched())
296                         cond_resched();
297
298                 /*
299                  * we made progress, there is more work to do and the bdi
300                  * is now congested.  Back off and let other work structs
301                  * run instead
302                  */
303                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
304                     fs_info->fs_devices->open_devices > 1) {
305                         struct io_context *ioc;
306
307                         ioc = current->io_context;
308
309                         /*
310                          * the main goal here is that we don't want to
311                          * block if we're going to be able to submit
312                          * more requests without blocking.
313                          *
314                          * This code does two great things, it pokes into
315                          * the elevator code from a filesystem _and_
316                          * it makes assumptions about how batching works.
317                          */
318                         if (ioc && ioc->nr_batch_requests > 0 &&
319                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
320                             (last_waited == 0 ||
321                              ioc->last_waited == last_waited)) {
322                                 /*
323                                  * we want to go through our batch of
324                                  * requests and stop.  So, we copy out
325                                  * the ioc->last_waited time and test
326                                  * against it before looping
327                                  */
328                                 last_waited = ioc->last_waited;
329                                 if (need_resched())
330                                         cond_resched();
331                                 continue;
332                         }
333                         spin_lock(&device->io_lock);
334                         requeue_list(pending_bios, pending, tail);
335                         device->running_pending = 1;
336
337                         spin_unlock(&device->io_lock);
338                         btrfs_requeue_work(&device->work);
339                         goto done;
340                 }
341                 /* unplug every 64 requests just for good measure */
342                 if (batch_run % 64 == 0) {
343                         blk_finish_plug(&plug);
344                         blk_start_plug(&plug);
345                         sync_pending = 0;
346                 }
347         }
348
349         cond_resched();
350         if (again)
351                 goto loop;
352
353         spin_lock(&device->io_lock);
354         if (device->pending_bios.head || device->pending_sync_bios.head)
355                 goto loop_lock;
356         spin_unlock(&device->io_lock);
357
358 done:
359         blk_finish_plug(&plug);
360 }
361
362 static void pending_bios_fn(struct btrfs_work *work)
363 {
364         struct btrfs_device *device;
365
366         device = container_of(work, struct btrfs_device, work);
367         run_scheduled_bios(device);
368 }
369
370 static noinline int device_list_add(const char *path,
371                            struct btrfs_super_block *disk_super,
372                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
373 {
374         struct btrfs_device *device;
375         struct btrfs_fs_devices *fs_devices;
376         struct rcu_string *name;
377         u64 found_transid = btrfs_super_generation(disk_super);
378
379         fs_devices = find_fsid(disk_super->fsid);
380         if (!fs_devices) {
381                 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
382                 if (!fs_devices)
383                         return -ENOMEM;
384                 INIT_LIST_HEAD(&fs_devices->devices);
385                 INIT_LIST_HEAD(&fs_devices->alloc_list);
386                 list_add(&fs_devices->list, &fs_uuids);
387                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
388                 fs_devices->latest_devid = devid;
389                 fs_devices->latest_trans = found_transid;
390                 mutex_init(&fs_devices->device_list_mutex);
391                 device = NULL;
392         } else {
393                 device = __find_device(&fs_devices->devices, devid,
394                                        disk_super->dev_item.uuid);
395         }
396         if (!device) {
397                 if (fs_devices->opened)
398                         return -EBUSY;
399
400                 device = kzalloc(sizeof(*device), GFP_NOFS);
401                 if (!device) {
402                         /* we can safely leave the fs_devices entry around */
403                         return -ENOMEM;
404                 }
405                 device->devid = devid;
406                 device->dev_stats_valid = 0;
407                 device->work.func = pending_bios_fn;
408                 memcpy(device->uuid, disk_super->dev_item.uuid,
409                        BTRFS_UUID_SIZE);
410                 spin_lock_init(&device->io_lock);
411
412                 name = rcu_string_strdup(path, GFP_NOFS);
413                 if (!name) {
414                         kfree(device);
415                         return -ENOMEM;
416                 }
417                 rcu_assign_pointer(device->name, name);
418                 INIT_LIST_HEAD(&device->dev_alloc_list);
419
420                 /* init readahead state */
421                 spin_lock_init(&device->reada_lock);
422                 device->reada_curr_zone = NULL;
423                 atomic_set(&device->reada_in_flight, 0);
424                 device->reada_next = 0;
425                 INIT_RADIX_TREE(&device->reada_zones, GFP_NOFS & ~__GFP_WAIT);
426                 INIT_RADIX_TREE(&device->reada_extents, GFP_NOFS & ~__GFP_WAIT);
427
428                 mutex_lock(&fs_devices->device_list_mutex);
429                 list_add_rcu(&device->dev_list, &fs_devices->devices);
430                 mutex_unlock(&fs_devices->device_list_mutex);
431
432                 device->fs_devices = fs_devices;
433                 fs_devices->num_devices++;
434         } else if (!device->name || strcmp(device->name->str, path)) {
435                 name = rcu_string_strdup(path, GFP_NOFS);
436                 if (!name)
437                         return -ENOMEM;
438                 rcu_string_free(device->name);
439                 rcu_assign_pointer(device->name, name);
440                 if (device->missing) {
441                         fs_devices->missing_devices--;
442                         device->missing = 0;
443                 }
444         }
445
446         if (found_transid > fs_devices->latest_trans) {
447                 fs_devices->latest_devid = devid;
448                 fs_devices->latest_trans = found_transid;
449         }
450         *fs_devices_ret = fs_devices;
451         return 0;
452 }
453
454 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
455 {
456         struct btrfs_fs_devices *fs_devices;
457         struct btrfs_device *device;
458         struct btrfs_device *orig_dev;
459
460         fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
461         if (!fs_devices)
462                 return ERR_PTR(-ENOMEM);
463
464         INIT_LIST_HEAD(&fs_devices->devices);
465         INIT_LIST_HEAD(&fs_devices->alloc_list);
466         INIT_LIST_HEAD(&fs_devices->list);
467         mutex_init(&fs_devices->device_list_mutex);
468         fs_devices->latest_devid = orig->latest_devid;
469         fs_devices->latest_trans = orig->latest_trans;
470         fs_devices->total_devices = orig->total_devices;
471         memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));
472
473         /* We have held the volume lock, it is safe to get the devices. */
474         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
475                 struct rcu_string *name;
476
477                 device = kzalloc(sizeof(*device), GFP_NOFS);
478                 if (!device)
479                         goto error;
480
481                 /*
482                  * This is ok to do without rcu read locked because we hold the
483                  * uuid mutex so nothing we touch in here is going to disappear.
484                  */
485                 name = rcu_string_strdup(orig_dev->name->str, GFP_NOFS);
486                 if (!name) {
487                         kfree(device);
488                         goto error;
489                 }
490                 rcu_assign_pointer(device->name, name);
491
492                 device->devid = orig_dev->devid;
493                 device->work.func = pending_bios_fn;
494                 memcpy(device->uuid, orig_dev->uuid, sizeof(device->uuid));
495                 spin_lock_init(&device->io_lock);
496                 INIT_LIST_HEAD(&device->dev_list);
497                 INIT_LIST_HEAD(&device->dev_alloc_list);
498
499                 list_add(&device->dev_list, &fs_devices->devices);
500                 device->fs_devices = fs_devices;
501                 fs_devices->num_devices++;
502         }
503         return fs_devices;
504 error:
505         free_fs_devices(fs_devices);
506         return ERR_PTR(-ENOMEM);
507 }
508
509 void btrfs_close_extra_devices(struct btrfs_fs_info *fs_info,
510                                struct btrfs_fs_devices *fs_devices, int step)
511 {
512         struct btrfs_device *device, *next;
513
514         struct block_device *latest_bdev = NULL;
515         u64 latest_devid = 0;
516         u64 latest_transid = 0;
517
518         mutex_lock(&uuid_mutex);
519 again:
520         /* This is the initialized path, it is safe to release the devices. */
521         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
522                 if (device->in_fs_metadata) {
523                         if (!device->is_tgtdev_for_dev_replace &&
524                             (!latest_transid ||
525                              device->generation > latest_transid)) {
526                                 latest_devid = device->devid;
527                                 latest_transid = device->generation;
528                                 latest_bdev = device->bdev;
529                         }
530                         continue;
531                 }
532
533                 if (device->devid == BTRFS_DEV_REPLACE_DEVID) {
534                         /*
535                          * In the first step, keep the device which has
536                          * the correct fsid and the devid that is used
537                          * for the dev_replace procedure.
538                          * In the second step, the dev_replace state is
539                          * read from the device tree and it is known
540                          * whether the procedure is really active or
541                          * not, which means whether this device is
542                          * used or whether it should be removed.
543                          */
544                         if (step == 0 || device->is_tgtdev_for_dev_replace) {
545                                 continue;
546                         }
547                 }
548                 if (device->bdev) {
549                         blkdev_put(device->bdev, device->mode);
550                         device->bdev = NULL;
551                         fs_devices->open_devices--;
552                 }
553                 if (device->writeable) {
554                         list_del_init(&device->dev_alloc_list);
555                         device->writeable = 0;
556                         if (!device->is_tgtdev_for_dev_replace)
557                                 fs_devices->rw_devices--;
558                 }
559                 list_del_init(&device->dev_list);
560                 fs_devices->num_devices--;
561                 rcu_string_free(device->name);
562                 kfree(device);
563         }
564
565         if (fs_devices->seed) {
566                 fs_devices = fs_devices->seed;
567                 goto again;
568         }
569
570         fs_devices->latest_bdev = latest_bdev;
571         fs_devices->latest_devid = latest_devid;
572         fs_devices->latest_trans = latest_transid;
573
574         mutex_unlock(&uuid_mutex);
575 }
576
577 static void __free_device(struct work_struct *work)
578 {
579         struct btrfs_device *device;
580
581         device = container_of(work, struct btrfs_device, rcu_work);
582
583         if (device->bdev)
584                 blkdev_put(device->bdev, device->mode);
585
586         rcu_string_free(device->name);
587         kfree(device);
588 }
589
590 static void free_device(struct rcu_head *head)
591 {
592         struct btrfs_device *device;
593
594         device = container_of(head, struct btrfs_device, rcu);
595
596         INIT_WORK(&device->rcu_work, __free_device);
597         schedule_work(&device->rcu_work);
598 }
599
600 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
601 {
602         struct btrfs_device *device;
603
604         if (--fs_devices->opened > 0)
605                 return 0;
606
607         mutex_lock(&fs_devices->device_list_mutex);
608         list_for_each_entry(device, &fs_devices->devices, dev_list) {
609                 struct btrfs_device *new_device;
610                 struct rcu_string *name;
611
612                 if (device->bdev)
613                         fs_devices->open_devices--;
614
615                 if (device->writeable && !device->is_tgtdev_for_dev_replace) {
616                         list_del_init(&device->dev_alloc_list);
617                         fs_devices->rw_devices--;
618                 }
619
620                 if (device->can_discard)
621                         fs_devices->num_can_discard--;
622
623                 new_device = kmalloc(sizeof(*new_device), GFP_NOFS);
624                 BUG_ON(!new_device); /* -ENOMEM */
625                 memcpy(new_device, device, sizeof(*new_device));
626
627                 /* Safe because we are under uuid_mutex */
628                 if (device->name) {
629                         name = rcu_string_strdup(device->name->str, GFP_NOFS);
630                         BUG_ON(device->name && !name); /* -ENOMEM */
631                         rcu_assign_pointer(new_device->name, name);
632                 }
633                 new_device->bdev = NULL;
634                 new_device->writeable = 0;
635                 new_device->in_fs_metadata = 0;
636                 new_device->can_discard = 0;
637                 list_replace_rcu(&device->dev_list, &new_device->dev_list);
638
639                 call_rcu(&device->rcu, free_device);
640         }
641         mutex_unlock(&fs_devices->device_list_mutex);
642
643         WARN_ON(fs_devices->open_devices);
644         WARN_ON(fs_devices->rw_devices);
645         fs_devices->opened = 0;
646         fs_devices->seeding = 0;
647
648         return 0;
649 }
650
651 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
652 {
653         struct btrfs_fs_devices *seed_devices = NULL;
654         int ret;
655
656         mutex_lock(&uuid_mutex);
657         ret = __btrfs_close_devices(fs_devices);
658         if (!fs_devices->opened) {
659                 seed_devices = fs_devices->seed;
660                 fs_devices->seed = NULL;
661         }
662         mutex_unlock(&uuid_mutex);
663
664         while (seed_devices) {
665                 fs_devices = seed_devices;
666                 seed_devices = fs_devices->seed;
667                 __btrfs_close_devices(fs_devices);
668                 free_fs_devices(fs_devices);
669         }
670         return ret;
671 }
672
673 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
674                                 fmode_t flags, void *holder)
675 {
676         struct request_queue *q;
677         struct block_device *bdev;
678         struct list_head *head = &fs_devices->devices;
679         struct btrfs_device *device;
680         struct block_device *latest_bdev = NULL;
681         struct buffer_head *bh;
682         struct btrfs_super_block *disk_super;
683         u64 latest_devid = 0;
684         u64 latest_transid = 0;
685         u64 devid;
686         int seeding = 1;
687         int ret = 0;
688
689         flags |= FMODE_EXCL;
690
691         list_for_each_entry(device, head, dev_list) {
692                 if (device->bdev)
693                         continue;
694                 if (!device->name)
695                         continue;
696
697                 ret = btrfs_get_bdev_and_sb(device->name->str, flags, holder, 1,
698                                             &bdev, &bh);
699                 if (ret)
700                         continue;
701
702                 disk_super = (struct btrfs_super_block *)bh->b_data;
703                 devid = btrfs_stack_device_id(&disk_super->dev_item);
704                 if (devid != device->devid)
705                         goto error_brelse;
706
707                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
708                            BTRFS_UUID_SIZE))
709                         goto error_brelse;
710
711                 device->generation = btrfs_super_generation(disk_super);
712                 if (!latest_transid || device->generation > latest_transid) {
713                         latest_devid = devid;
714                         latest_transid = device->generation;
715                         latest_bdev = bdev;
716                 }
717
718                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
719                         device->writeable = 0;
720                 } else {
721                         device->writeable = !bdev_read_only(bdev);
722                         seeding = 0;
723                 }
724
725                 q = bdev_get_queue(bdev);
726                 if (blk_queue_discard(q)) {
727                         device->can_discard = 1;
728                         fs_devices->num_can_discard++;
729                 }
730
731                 device->bdev = bdev;
732                 device->in_fs_metadata = 0;
733                 device->mode = flags;
734
735                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
736                         fs_devices->rotating = 1;
737
738                 fs_devices->open_devices++;
739                 if (device->writeable && !device->is_tgtdev_for_dev_replace) {
740                         fs_devices->rw_devices++;
741                         list_add(&device->dev_alloc_list,
742                                  &fs_devices->alloc_list);
743                 }
744                 brelse(bh);
745                 continue;
746
747 error_brelse:
748                 brelse(bh);
749                 blkdev_put(bdev, flags);
750                 continue;
751         }
752         if (fs_devices->open_devices == 0) {
753                 ret = -EINVAL;
754                 goto out;
755         }
756         fs_devices->seeding = seeding;
757         fs_devices->opened = 1;
758         fs_devices->latest_bdev = latest_bdev;
759         fs_devices->latest_devid = latest_devid;
760         fs_devices->latest_trans = latest_transid;
761         fs_devices->total_rw_bytes = 0;
762 out:
763         return ret;
764 }
765
766 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
767                        fmode_t flags, void *holder)
768 {
769         int ret;
770
771         mutex_lock(&uuid_mutex);
772         if (fs_devices->opened) {
773                 fs_devices->opened++;
774                 ret = 0;
775         } else {
776                 ret = __btrfs_open_devices(fs_devices, flags, holder);
777         }
778         mutex_unlock(&uuid_mutex);
779         return ret;
780 }
781
782 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
783                           struct btrfs_fs_devices **fs_devices_ret)
784 {
785         struct btrfs_super_block *disk_super;
786         struct block_device *bdev;
787         struct buffer_head *bh;
788         int ret;
789         u64 devid;
790         u64 transid;
791         u64 total_devices;
792
793         flags |= FMODE_EXCL;
794         mutex_lock(&uuid_mutex);
795         ret = btrfs_get_bdev_and_sb(path, flags, holder, 0, &bdev, &bh);
796         if (ret)
797                 goto error;
798         disk_super = (struct btrfs_super_block *)bh->b_data;
799         devid = btrfs_stack_device_id(&disk_super->dev_item);
800         transid = btrfs_super_generation(disk_super);
801         total_devices = btrfs_super_num_devices(disk_super);
802         if (disk_super->label[0]) {
803                 if (disk_super->label[BTRFS_LABEL_SIZE - 1])
804                         disk_super->label[BTRFS_LABEL_SIZE - 1] = '\0';
805                 printk(KERN_INFO "device label %s ", disk_super->label);
806         } else {
807                 printk(KERN_INFO "device fsid %pU ", disk_super->fsid);
808         }
809         printk(KERN_CONT "devid %llu transid %llu %s\n",
810                (unsigned long long)devid, (unsigned long long)transid, path);
811         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
812         if (!ret && fs_devices_ret)
813                 (*fs_devices_ret)->total_devices = total_devices;
814         brelse(bh);
815         blkdev_put(bdev, flags);
816 error:
817         mutex_unlock(&uuid_mutex);
818         return ret;
819 }
820
821 /* helper to account the used device space in the range */
822 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
823                                    u64 end, u64 *length)
824 {
825         struct btrfs_key key;
826         struct btrfs_root *root = device->dev_root;
827         struct btrfs_dev_extent *dev_extent;
828         struct btrfs_path *path;
829         u64 extent_end;
830         int ret;
831         int slot;
832         struct extent_buffer *l;
833
834         *length = 0;
835
836         if (start >= device->total_bytes || device->is_tgtdev_for_dev_replace)
837                 return 0;
838
839         path = btrfs_alloc_path();
840         if (!path)
841                 return -ENOMEM;
842         path->reada = 2;
843
844         key.objectid = device->devid;
845         key.offset = start;
846         key.type = BTRFS_DEV_EXTENT_KEY;
847
848         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
849         if (ret < 0)
850                 goto out;
851         if (ret > 0) {
852                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
853                 if (ret < 0)
854                         goto out;
855         }
856
857         while (1) {
858                 l = path->nodes[0];
859                 slot = path->slots[0];
860                 if (slot >= btrfs_header_nritems(l)) {
861                         ret = btrfs_next_leaf(root, path);
862                         if (ret == 0)
863                                 continue;
864                         if (ret < 0)
865                                 goto out;
866
867                         break;
868                 }
869                 btrfs_item_key_to_cpu(l, &key, slot);
870
871                 if (key.objectid < device->devid)
872                         goto next;
873
874                 if (key.objectid > device->devid)
875                         break;
876
877                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
878                         goto next;
879
880                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
881                 extent_end = key.offset + btrfs_dev_extent_length(l,
882                                                                   dev_extent);
883                 if (key.offset <= start && extent_end > end) {
884                         *length = end - start + 1;
885                         break;
886                 } else if (key.offset <= start && extent_end > start)
887                         *length += extent_end - start;
888                 else if (key.offset > start && extent_end <= end)
889                         *length += extent_end - key.offset;
890                 else if (key.offset > start && key.offset <= end) {
891                         *length += end - key.offset + 1;
892                         break;
893                 } else if (key.offset > end)
894                         break;
895
896 next:
897                 path->slots[0]++;
898         }
899         ret = 0;
900 out:
901         btrfs_free_path(path);
902         return ret;
903 }
904
905 /*
906  * find_free_dev_extent - find free space in the specified device
907  * @device:     the device which we search the free space in
908  * @num_bytes:  the size of the free space that we need
909  * @start:      store the start of the free space.
910  * @len:        the size of the free space. that we find, or the size of the max
911  *              free space if we don't find suitable free space
912  *
913  * this uses a pretty simple search, the expectation is that it is
914  * called very infrequently and that a given device has a small number
915  * of extents
916  *
917  * @start is used to store the start of the free space if we find. But if we
918  * don't find suitable free space, it will be used to store the start position
919  * of the max free space.
920  *
921  * @len is used to store the size of the free space that we find.
922  * But if we don't find suitable free space, it is used to store the size of
923  * the max free space.
924  */
925 int find_free_dev_extent(struct btrfs_device *device, u64 num_bytes,
926                          u64 *start, u64 *len)
927 {
928         struct btrfs_key key;
929         struct btrfs_root *root = device->dev_root;
930         struct btrfs_dev_extent *dev_extent;
931         struct btrfs_path *path;
932         u64 hole_size;
933         u64 max_hole_start;
934         u64 max_hole_size;
935         u64 extent_end;
936         u64 search_start;
937         u64 search_end = device->total_bytes;
938         int ret;
939         int slot;
940         struct extent_buffer *l;
941
942         /* FIXME use last free of some kind */
943
944         /* we don't want to overwrite the superblock on the drive,
945          * so we make sure to start at an offset of at least 1MB
946          */
947         search_start = max(root->fs_info->alloc_start, 1024ull * 1024);
948
949         max_hole_start = search_start;
950         max_hole_size = 0;
951         hole_size = 0;
952
953         if (search_start >= search_end || device->is_tgtdev_for_dev_replace) {
954                 ret = -ENOSPC;
955                 goto error;
956         }
957
958         path = btrfs_alloc_path();
959         if (!path) {
960                 ret = -ENOMEM;
961                 goto error;
962         }
963         path->reada = 2;
964
965         key.objectid = device->devid;
966         key.offset = search_start;
967         key.type = BTRFS_DEV_EXTENT_KEY;
968
969         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
970         if (ret < 0)
971                 goto out;
972         if (ret > 0) {
973                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
974                 if (ret < 0)
975                         goto out;
976         }
977
978         while (1) {
979                 l = path->nodes[0];
980                 slot = path->slots[0];
981                 if (slot >= btrfs_header_nritems(l)) {
982                         ret = btrfs_next_leaf(root, path);
983                         if (ret == 0)
984                                 continue;
985                         if (ret < 0)
986                                 goto out;
987
988                         break;
989                 }
990                 btrfs_item_key_to_cpu(l, &key, slot);
991
992                 if (key.objectid < device->devid)
993                         goto next;
994
995                 if (key.objectid > device->devid)
996                         break;
997
998                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
999                         goto next;
1000
1001                 if (key.offset > search_start) {
1002                         hole_size = key.offset - search_start;
1003
1004                         if (hole_size > max_hole_size) {
1005                                 max_hole_start = search_start;
1006                                 max_hole_size = hole_size;
1007                         }
1008
1009                         /*
1010                          * If this free space is greater than which we need,
1011                          * it must be the max free space that we have found
1012                          * until now, so max_hole_start must point to the start
1013                          * of this free space and the length of this free space
1014                          * is stored in max_hole_size. Thus, we return
1015                          * max_hole_start and max_hole_size and go back to the
1016                          * caller.
1017                          */
1018                         if (hole_size >= num_bytes) {
1019                                 ret = 0;
1020                                 goto out;
1021                         }
1022                 }
1023
1024                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1025                 extent_end = key.offset + btrfs_dev_extent_length(l,
1026                                                                   dev_extent);
1027                 if (extent_end > search_start)
1028                         search_start = extent_end;
1029 next:
1030                 path->slots[0]++;
1031                 cond_resched();
1032         }
1033
1034         /*
1035          * At this point, search_start should be the end of
1036          * allocated dev extents, and when shrinking the device,
1037          * search_end may be smaller than search_start.
1038          */
1039         if (search_end > search_start)
1040                 hole_size = search_end - search_start;
1041
1042         if (hole_size > max_hole_size) {
1043                 max_hole_start = search_start;
1044                 max_hole_size = hole_size;
1045         }
1046
1047         /* See above. */
1048         if (hole_size < num_bytes)
1049                 ret = -ENOSPC;
1050         else
1051                 ret = 0;
1052
1053 out:
1054         btrfs_free_path(path);
1055 error:
1056         *start = max_hole_start;
1057         if (len)
1058                 *len = max_hole_size;
1059         return ret;
1060 }
1061
1062 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
1063                           struct btrfs_device *device,
1064                           u64 start)
1065 {
1066         int ret;
1067         struct btrfs_path *path;
1068         struct btrfs_root *root = device->dev_root;
1069         struct btrfs_key key;
1070         struct btrfs_key found_key;
1071         struct extent_buffer *leaf = NULL;
1072         struct btrfs_dev_extent *extent = NULL;
1073
1074         path = btrfs_alloc_path();
1075         if (!path)
1076                 return -ENOMEM;
1077
1078         key.objectid = device->devid;
1079         key.offset = start;
1080         key.type = BTRFS_DEV_EXTENT_KEY;
1081 again:
1082         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1083         if (ret > 0) {
1084                 ret = btrfs_previous_item(root, path, key.objectid,
1085                                           BTRFS_DEV_EXTENT_KEY);
1086                 if (ret)
1087                         goto out;
1088                 leaf = path->nodes[0];
1089                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1090                 extent = btrfs_item_ptr(leaf, path->slots[0],
1091                                         struct btrfs_dev_extent);
1092                 BUG_ON(found_key.offset > start || found_key.offset +
1093                        btrfs_dev_extent_length(leaf, extent) < start);
1094                 key = found_key;
1095                 btrfs_release_path(path);
1096                 goto again;
1097         } else if (ret == 0) {
1098                 leaf = path->nodes[0];
1099                 extent = btrfs_item_ptr(leaf, path->slots[0],
1100                                         struct btrfs_dev_extent);
1101         } else {
1102                 btrfs_error(root->fs_info, ret, "Slot search failed");
1103                 goto out;
1104         }
1105
1106         if (device->bytes_used > 0) {
1107                 u64 len = btrfs_dev_extent_length(leaf, extent);
1108                 device->bytes_used -= len;
1109                 spin_lock(&root->fs_info->free_chunk_lock);
1110                 root->fs_info->free_chunk_space += len;
1111                 spin_unlock(&root->fs_info->free_chunk_lock);
1112         }
1113         ret = btrfs_del_item(trans, root, path);
1114         if (ret) {
1115                 btrfs_error(root->fs_info, ret,
1116                             "Failed to remove dev extent item");
1117         }
1118 out:
1119         btrfs_free_path(path);
1120         return ret;
1121 }
1122
1123 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
1124                            struct btrfs_device *device,
1125                            u64 chunk_tree, u64 chunk_objectid,
1126                            u64 chunk_offset, u64 start, u64 num_bytes)
1127 {
1128         int ret;
1129         struct btrfs_path *path;
1130         struct btrfs_root *root = device->dev_root;
1131         struct btrfs_dev_extent *extent;
1132         struct extent_buffer *leaf;
1133         struct btrfs_key key;
1134
1135         WARN_ON(!device->in_fs_metadata);
1136         WARN_ON(device->is_tgtdev_for_dev_replace);
1137         path = btrfs_alloc_path();
1138         if (!path)
1139                 return -ENOMEM;
1140
1141         key.objectid = device->devid;
1142         key.offset = start;
1143         key.type = BTRFS_DEV_EXTENT_KEY;
1144         ret = btrfs_insert_empty_item(trans, root, path, &key,
1145                                       sizeof(*extent));
1146         if (ret)
1147                 goto out;
1148
1149         leaf = path->nodes[0];
1150         extent = btrfs_item_ptr(leaf, path->slots[0],
1151                                 struct btrfs_dev_extent);
1152         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
1153         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
1154         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
1155
1156         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
1157                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
1158                     BTRFS_UUID_SIZE);
1159
1160         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
1161         btrfs_mark_buffer_dirty(leaf);
1162 out:
1163         btrfs_free_path(path);
1164         return ret;
1165 }
1166
1167 static noinline int find_next_chunk(struct btrfs_root *root,
1168                                     u64 objectid, u64 *offset)
1169 {
1170         struct btrfs_path *path;
1171         int ret;
1172         struct btrfs_key key;
1173         struct btrfs_chunk *chunk;
1174         struct btrfs_key found_key;
1175
1176         path = btrfs_alloc_path();
1177         if (!path)
1178                 return -ENOMEM;
1179
1180         key.objectid = objectid;
1181         key.offset = (u64)-1;
1182         key.type = BTRFS_CHUNK_ITEM_KEY;
1183
1184         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1185         if (ret < 0)
1186                 goto error;
1187
1188         BUG_ON(ret == 0); /* Corruption */
1189
1190         ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
1191         if (ret) {
1192                 *offset = 0;
1193         } else {
1194                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1195                                       path->slots[0]);
1196                 if (found_key.objectid != objectid)
1197                         *offset = 0;
1198                 else {
1199                         chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
1200                                                struct btrfs_chunk);
1201                         *offset = found_key.offset +
1202                                 btrfs_chunk_length(path->nodes[0], chunk);
1203                 }
1204         }
1205         ret = 0;
1206 error:
1207         btrfs_free_path(path);
1208         return ret;
1209 }
1210
1211 static noinline int find_next_devid(struct btrfs_root *root, u64 *objectid)
1212 {
1213         int ret;
1214         struct btrfs_key key;
1215         struct btrfs_key found_key;
1216         struct btrfs_path *path;
1217
1218         root = root->fs_info->chunk_root;
1219
1220         path = btrfs_alloc_path();
1221         if (!path)
1222                 return -ENOMEM;
1223
1224         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1225         key.type = BTRFS_DEV_ITEM_KEY;
1226         key.offset = (u64)-1;
1227
1228         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1229         if (ret < 0)
1230                 goto error;
1231
1232         BUG_ON(ret == 0); /* Corruption */
1233
1234         ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
1235                                   BTRFS_DEV_ITEM_KEY);
1236         if (ret) {
1237                 *objectid = 1;
1238         } else {
1239                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1240                                       path->slots[0]);
1241                 *objectid = found_key.offset + 1;
1242         }
1243         ret = 0;
1244 error:
1245         btrfs_free_path(path);
1246         return ret;
1247 }
1248
1249 /*
1250  * the device information is stored in the chunk root
1251  * the btrfs_device struct should be fully filled in
1252  */
1253 int btrfs_add_device(struct btrfs_trans_handle *trans,
1254                      struct btrfs_root *root,
1255                      struct btrfs_device *device)
1256 {
1257         int ret;
1258         struct btrfs_path *path;
1259         struct btrfs_dev_item *dev_item;
1260         struct extent_buffer *leaf;
1261         struct btrfs_key key;
1262         unsigned long ptr;
1263
1264         root = root->fs_info->chunk_root;
1265
1266         path = btrfs_alloc_path();
1267         if (!path)
1268                 return -ENOMEM;
1269
1270         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1271         key.type = BTRFS_DEV_ITEM_KEY;
1272         key.offset = device->devid;
1273
1274         ret = btrfs_insert_empty_item(trans, root, path, &key,
1275                                       sizeof(*dev_item));
1276         if (ret)
1277                 goto out;
1278
1279         leaf = path->nodes[0];
1280         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1281
1282         btrfs_set_device_id(leaf, dev_item, device->devid);
1283         btrfs_set_device_generation(leaf, dev_item, 0);
1284         btrfs_set_device_type(leaf, dev_item, device->type);
1285         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1286         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1287         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1288         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
1289         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1290         btrfs_set_device_group(leaf, dev_item, 0);
1291         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1292         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1293         btrfs_set_device_start_offset(leaf, dev_item, 0);
1294
1295         ptr = (unsigned long)btrfs_device_uuid(dev_item);
1296         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1297         ptr = (unsigned long)btrfs_device_fsid(dev_item);
1298         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1299         btrfs_mark_buffer_dirty(leaf);
1300
1301         ret = 0;
1302 out:
1303         btrfs_free_path(path);
1304         return ret;
1305 }
1306
1307 static int btrfs_rm_dev_item(struct btrfs_root *root,
1308                              struct btrfs_device *device)
1309 {
1310         int ret;
1311         struct btrfs_path *path;
1312         struct btrfs_key key;
1313         struct btrfs_trans_handle *trans;
1314
1315         root = root->fs_info->chunk_root;
1316
1317         path = btrfs_alloc_path();
1318         if (!path)
1319                 return -ENOMEM;
1320
1321         trans = btrfs_start_transaction(root, 0);
1322         if (IS_ERR(trans)) {
1323                 btrfs_free_path(path);
1324                 return PTR_ERR(trans);
1325         }
1326         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1327         key.type = BTRFS_DEV_ITEM_KEY;
1328         key.offset = device->devid;
1329         lock_chunks(root);
1330
1331         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1332         if (ret < 0)
1333                 goto out;
1334
1335         if (ret > 0) {
1336                 ret = -ENOENT;
1337                 goto out;
1338         }
1339
1340         ret = btrfs_del_item(trans, root, path);
1341         if (ret)
1342                 goto out;
1343 out:
1344         btrfs_free_path(path);
1345         unlock_chunks(root);
1346         btrfs_commit_transaction(trans, root);
1347         return ret;
1348 }
1349
1350 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1351 {
1352         struct btrfs_device *device;
1353         struct btrfs_device *next_device;
1354         struct block_device *bdev;
1355         struct buffer_head *bh = NULL;
1356         struct btrfs_super_block *disk_super;
1357         struct btrfs_fs_devices *cur_devices;
1358         u64 all_avail;
1359         u64 devid;
1360         u64 num_devices;
1361         u8 *dev_uuid;
1362         int ret = 0;
1363         bool clear_super = false;
1364
1365         mutex_lock(&uuid_mutex);
1366
1367         all_avail = root->fs_info->avail_data_alloc_bits |
1368                 root->fs_info->avail_system_alloc_bits |
1369                 root->fs_info->avail_metadata_alloc_bits;
1370
1371         num_devices = root->fs_info->fs_devices->num_devices;
1372         btrfs_dev_replace_lock(&root->fs_info->dev_replace);
1373         if (btrfs_dev_replace_is_ongoing(&root->fs_info->dev_replace)) {
1374                 WARN_ON(num_devices < 1);
1375                 num_devices--;
1376         }
1377         btrfs_dev_replace_unlock(&root->fs_info->dev_replace);
1378
1379         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) && num_devices <= 4) {
1380                 printk(KERN_ERR "btrfs: unable to go below four devices "
1381                        "on raid10\n");
1382                 ret = -EINVAL;
1383                 goto out;
1384         }
1385
1386         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) && num_devices <= 2) {
1387                 printk(KERN_ERR "btrfs: unable to go below two "
1388                        "devices on raid1\n");
1389                 ret = -EINVAL;
1390                 goto out;
1391         }
1392
1393         if (strcmp(device_path, "missing") == 0) {
1394                 struct list_head *devices;
1395                 struct btrfs_device *tmp;
1396
1397                 device = NULL;
1398                 devices = &root->fs_info->fs_devices->devices;
1399                 /*
1400                  * It is safe to read the devices since the volume_mutex
1401                  * is held.
1402                  */
1403                 list_for_each_entry(tmp, devices, dev_list) {
1404                         if (tmp->in_fs_metadata &&
1405                             !tmp->is_tgtdev_for_dev_replace &&
1406                             !tmp->bdev) {
1407                                 device = tmp;
1408                                 break;
1409                         }
1410                 }
1411                 bdev = NULL;
1412                 bh = NULL;
1413                 disk_super = NULL;
1414                 if (!device) {
1415                         printk(KERN_ERR "btrfs: no missing devices found to "
1416                                "remove\n");
1417                         goto out;
1418                 }
1419         } else {
1420                 ret = btrfs_get_bdev_and_sb(device_path,
1421                                             FMODE_READ | FMODE_EXCL,
1422                                             root->fs_info->bdev_holder, 0,
1423                                             &bdev, &bh);
1424                 if (ret)
1425                         goto out;
1426                 disk_super = (struct btrfs_super_block *)bh->b_data;
1427                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1428                 dev_uuid = disk_super->dev_item.uuid;
1429                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1430                                            disk_super->fsid);
1431                 if (!device) {
1432                         ret = -ENOENT;
1433                         goto error_brelse;
1434                 }
1435         }
1436
1437         if (device->is_tgtdev_for_dev_replace) {
1438                 pr_err("btrfs: unable to remove the dev_replace target dev\n");
1439                 ret = -EINVAL;
1440                 goto error_brelse;
1441         }
1442
1443         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1444                 printk(KERN_ERR "btrfs: unable to remove the only writeable "
1445                        "device\n");
1446                 ret = -EINVAL;
1447                 goto error_brelse;
1448         }
1449
1450         if (device->writeable) {
1451                 lock_chunks(root);
1452                 list_del_init(&device->dev_alloc_list);
1453                 unlock_chunks(root);
1454                 root->fs_info->fs_devices->rw_devices--;
1455                 clear_super = true;
1456         }
1457
1458         ret = btrfs_shrink_device(device, 0);
1459         if (ret)
1460                 goto error_undo;
1461
1462         /*
1463          * TODO: the superblock still includes this device in its num_devices
1464          * counter although write_all_supers() is not locked out. This
1465          * could give a filesystem state which requires a degraded mount.
1466          */
1467         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1468         if (ret)
1469                 goto error_undo;
1470
1471         spin_lock(&root->fs_info->free_chunk_lock);
1472         root->fs_info->free_chunk_space = device->total_bytes -
1473                 device->bytes_used;
1474         spin_unlock(&root->fs_info->free_chunk_lock);
1475
1476         device->in_fs_metadata = 0;
1477         btrfs_scrub_cancel_dev(root->fs_info, device);
1478
1479         /*
1480          * the device list mutex makes sure that we don't change
1481          * the device list while someone else is writing out all
1482          * the device supers.
1483          */
1484
1485         cur_devices = device->fs_devices;
1486         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1487         list_del_rcu(&device->dev_list);
1488
1489         device->fs_devices->num_devices--;
1490         device->fs_devices->total_devices--;
1491
1492         if (device->missing)
1493                 root->fs_info->fs_devices->missing_devices--;
1494
1495         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1496                                  struct btrfs_device, dev_list);
1497         if (device->bdev == root->fs_info->sb->s_bdev)
1498                 root->fs_info->sb->s_bdev = next_device->bdev;
1499         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1500                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1501
1502         if (device->bdev)
1503                 device->fs_devices->open_devices--;
1504
1505         call_rcu(&device->rcu, free_device);
1506         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1507
1508         num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
1509         btrfs_set_super_num_devices(root->fs_info->super_copy, num_devices);
1510
1511         if (cur_devices->open_devices == 0) {
1512                 struct btrfs_fs_devices *fs_devices;
1513                 fs_devices = root->fs_info->fs_devices;
1514                 while (fs_devices) {
1515                         if (fs_devices->seed == cur_devices)
1516                                 break;
1517                         fs_devices = fs_devices->seed;
1518                 }
1519                 fs_devices->seed = cur_devices->seed;
1520                 cur_devices->seed = NULL;
1521                 lock_chunks(root);
1522                 __btrfs_close_devices(cur_devices);
1523                 unlock_chunks(root);
1524                 free_fs_devices(cur_devices);
1525         }
1526
1527         root->fs_info->num_tolerated_disk_barrier_failures =
1528                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1529
1530         /*
1531          * at this point, the device is zero sized.  We want to
1532          * remove it from the devices list and zero out the old super
1533          */
1534         if (clear_super && disk_super) {
1535                 /* make sure this device isn't detected as part of
1536                  * the FS anymore
1537                  */
1538                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1539                 set_buffer_dirty(bh);
1540                 sync_dirty_buffer(bh);
1541         }
1542
1543         ret = 0;
1544
1545 error_brelse:
1546         brelse(bh);
1547         if (bdev)
1548                 blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
1549 out:
1550         mutex_unlock(&uuid_mutex);
1551         return ret;
1552 error_undo:
1553         if (device->writeable) {
1554                 lock_chunks(root);
1555                 list_add(&device->dev_alloc_list,
1556                          &root->fs_info->fs_devices->alloc_list);
1557                 unlock_chunks(root);
1558                 root->fs_info->fs_devices->rw_devices++;
1559         }
1560         goto error_brelse;
1561 }
1562
1563 void btrfs_rm_dev_replace_srcdev(struct btrfs_fs_info *fs_info,
1564                                  struct btrfs_device *srcdev)
1565 {
1566         WARN_ON(!mutex_is_locked(&fs_info->fs_devices->device_list_mutex));
1567         list_del_rcu(&srcdev->dev_list);
1568         list_del_rcu(&srcdev->dev_alloc_list);
1569         fs_info->fs_devices->num_devices--;
1570         if (srcdev->missing) {
1571                 fs_info->fs_devices->missing_devices--;
1572                 fs_info->fs_devices->rw_devices++;
1573         }
1574         if (srcdev->can_discard)
1575                 fs_info->fs_devices->num_can_discard--;
1576         if (srcdev->bdev)
1577                 fs_info->fs_devices->open_devices--;
1578
1579         call_rcu(&srcdev->rcu, free_device);
1580 }
1581
1582 void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
1583                                       struct btrfs_device *tgtdev)
1584 {
1585         struct btrfs_device *next_device;
1586
1587         WARN_ON(!tgtdev);
1588         mutex_lock(&fs_info->fs_devices->device_list_mutex);
1589         if (tgtdev->bdev) {
1590                 btrfs_scratch_superblock(tgtdev);
1591                 fs_info->fs_devices->open_devices--;
1592         }
1593         fs_info->fs_devices->num_devices--;
1594         if (tgtdev->can_discard)
1595                 fs_info->fs_devices->num_can_discard++;
1596
1597         next_device = list_entry(fs_info->fs_devices->devices.next,
1598                                  struct btrfs_device, dev_list);
1599         if (tgtdev->bdev == fs_info->sb->s_bdev)
1600                 fs_info->sb->s_bdev = next_device->bdev;
1601         if (tgtdev->bdev == fs_info->fs_devices->latest_bdev)
1602                 fs_info->fs_devices->latest_bdev = next_device->bdev;
1603         list_del_rcu(&tgtdev->dev_list);
1604
1605         call_rcu(&tgtdev->rcu, free_device);
1606
1607         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1608 }
1609
1610 int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
1611                               struct btrfs_device **device)
1612 {
1613         int ret = 0;
1614         struct btrfs_super_block *disk_super;
1615         u64 devid;
1616         u8 *dev_uuid;
1617         struct block_device *bdev;
1618         struct buffer_head *bh;
1619
1620         *device = NULL;
1621         ret = btrfs_get_bdev_and_sb(device_path, FMODE_READ,
1622                                     root->fs_info->bdev_holder, 0, &bdev, &bh);
1623         if (ret)
1624                 return ret;
1625         disk_super = (struct btrfs_super_block *)bh->b_data;
1626         devid = btrfs_stack_device_id(&disk_super->dev_item);
1627         dev_uuid = disk_super->dev_item.uuid;
1628         *device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1629                                     disk_super->fsid);
1630         brelse(bh);
1631         if (!*device)
1632                 ret = -ENOENT;
1633         blkdev_put(bdev, FMODE_READ);
1634         return ret;
1635 }
1636
1637 int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
1638                                          char *device_path,
1639                                          struct btrfs_device **device)
1640 {
1641         *device = NULL;
1642         if (strcmp(device_path, "missing") == 0) {
1643                 struct list_head *devices;
1644                 struct btrfs_device *tmp;
1645
1646                 devices = &root->fs_info->fs_devices->devices;
1647                 /*
1648                  * It is safe to read the devices since the volume_mutex
1649                  * is held by the caller.
1650                  */
1651                 list_for_each_entry(tmp, devices, dev_list) {
1652                         if (tmp->in_fs_metadata && !tmp->bdev) {
1653                                 *device = tmp;
1654                                 break;
1655                         }
1656                 }
1657
1658                 if (!*device) {
1659                         pr_err("btrfs: no missing device found\n");
1660                         return -ENOENT;
1661                 }
1662
1663                 return 0;
1664         } else {
1665                 return btrfs_find_device_by_path(root, device_path, device);
1666         }
1667 }
1668
1669 /*
1670  * does all the dirty work required for changing file system's UUID.
1671  */
1672 static int btrfs_prepare_sprout(struct btrfs_root *root)
1673 {
1674         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
1675         struct btrfs_fs_devices *old_devices;
1676         struct btrfs_fs_devices *seed_devices;
1677         struct btrfs_super_block *disk_super = root->fs_info->super_copy;
1678         struct btrfs_device *device;
1679         u64 super_flags;
1680
1681         BUG_ON(!mutex_is_locked(&uuid_mutex));
1682         if (!fs_devices->seeding)
1683                 return -EINVAL;
1684
1685         seed_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
1686         if (!seed_devices)
1687                 return -ENOMEM;
1688
1689         old_devices = clone_fs_devices(fs_devices);
1690         if (IS_ERR(old_devices)) {
1691                 kfree(seed_devices);
1692                 return PTR_ERR(old_devices);
1693         }
1694
1695         list_add(&old_devices->list, &fs_uuids);
1696
1697         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
1698         seed_devices->opened = 1;
1699         INIT_LIST_HEAD(&seed_devices->devices);
1700         INIT_LIST_HEAD(&seed_devices->alloc_list);
1701         mutex_init(&seed_devices->device_list_mutex);
1702
1703         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1704         list_splice_init_rcu(&fs_devices->devices, &seed_devices->devices,
1705                               synchronize_rcu);
1706         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1707
1708         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
1709         list_for_each_entry(device, &seed_devices->devices, dev_list) {
1710                 device->fs_devices = seed_devices;
1711         }
1712
1713         fs_devices->seeding = 0;
1714         fs_devices->num_devices = 0;
1715         fs_devices->open_devices = 0;
1716         fs_devices->total_devices = 0;
1717         fs_devices->seed = seed_devices;
1718
1719         generate_random_uuid(fs_devices->fsid);
1720         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1721         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1722         super_flags = btrfs_super_flags(disk_super) &
1723                       ~BTRFS_SUPER_FLAG_SEEDING;
1724         btrfs_set_super_flags(disk_super, super_flags);
1725
1726         return 0;
1727 }
1728
1729 /*
1730  * strore the expected generation for seed devices in device items.
1731  */
1732 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
1733                                struct btrfs_root *root)
1734 {
1735         struct btrfs_path *path;
1736         struct extent_buffer *leaf;
1737         struct btrfs_dev_item *dev_item;
1738         struct btrfs_device *device;
1739         struct btrfs_key key;
1740         u8 fs_uuid[BTRFS_UUID_SIZE];
1741         u8 dev_uuid[BTRFS_UUID_SIZE];
1742         u64 devid;
1743         int ret;
1744
1745         path = btrfs_alloc_path();
1746         if (!path)
1747                 return -ENOMEM;
1748
1749         root = root->fs_info->chunk_root;
1750         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1751         key.offset = 0;
1752         key.type = BTRFS_DEV_ITEM_KEY;
1753
1754         while (1) {
1755                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1756                 if (ret < 0)
1757                         goto error;
1758
1759                 leaf = path->nodes[0];
1760 next_slot:
1761                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1762                         ret = btrfs_next_leaf(root, path);
1763                         if (ret > 0)
1764                                 break;
1765                         if (ret < 0)
1766                                 goto error;
1767                         leaf = path->nodes[0];
1768                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1769                         btrfs_release_path(path);
1770                         continue;
1771                 }
1772
1773                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1774                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
1775                     key.type != BTRFS_DEV_ITEM_KEY)
1776                         break;
1777
1778                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
1779                                           struct btrfs_dev_item);
1780                 devid = btrfs_device_id(leaf, dev_item);
1781                 read_extent_buffer(leaf, dev_uuid,
1782                                    (unsigned long)btrfs_device_uuid(dev_item),
1783                                    BTRFS_UUID_SIZE);
1784                 read_extent_buffer(leaf, fs_uuid,
1785                                    (unsigned long)btrfs_device_fsid(dev_item),
1786                                    BTRFS_UUID_SIZE);
1787                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1788                                            fs_uuid);
1789                 BUG_ON(!device); /* Logic error */
1790
1791                 if (device->fs_devices->seeding) {
1792                         btrfs_set_device_generation(leaf, dev_item,
1793                                                     device->generation);
1794                         btrfs_mark_buffer_dirty(leaf);
1795                 }
1796
1797                 path->slots[0]++;
1798                 goto next_slot;
1799         }
1800         ret = 0;
1801 error:
1802         btrfs_free_path(path);
1803         return ret;
1804 }
1805
1806 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
1807 {
1808         struct request_queue *q;
1809         struct btrfs_trans_handle *trans;
1810         struct btrfs_device *device;
1811         struct block_device *bdev;
1812         struct list_head *devices;
1813         struct super_block *sb = root->fs_info->sb;
1814         struct rcu_string *name;
1815         u64 total_bytes;
1816         int seeding_dev = 0;
1817         int ret = 0;
1818
1819         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
1820                 return -EROFS;
1821
1822         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
1823                                   root->fs_info->bdev_holder);
1824         if (IS_ERR(bdev))
1825                 return PTR_ERR(bdev);
1826
1827         if (root->fs_info->fs_devices->seeding) {
1828                 seeding_dev = 1;
1829                 down_write(&sb->s_umount);
1830                 mutex_lock(&uuid_mutex);
1831         }
1832
1833         filemap_write_and_wait(bdev->bd_inode->i_mapping);
1834
1835         devices = &root->fs_info->fs_devices->devices;
1836
1837         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1838         list_for_each_entry(device, devices, dev_list) {
1839                 if (device->bdev == bdev) {
1840                         ret = -EEXIST;
1841                         mutex_unlock(
1842                                 &root->fs_info->fs_devices->device_list_mutex);
1843                         goto error;
1844                 }
1845         }
1846         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1847
1848         device = kzalloc(sizeof(*device), GFP_NOFS);
1849         if (!device) {
1850                 /* we can safely leave the fs_devices entry around */
1851                 ret = -ENOMEM;
1852                 goto error;
1853         }
1854
1855         name = rcu_string_strdup(device_path, GFP_NOFS);
1856         if (!name) {
1857                 kfree(device);
1858                 ret = -ENOMEM;
1859                 goto error;
1860         }
1861         rcu_assign_pointer(device->name, name);
1862
1863         ret = find_next_devid(root, &device->devid);
1864         if (ret) {
1865                 rcu_string_free(device->name);
1866                 kfree(device);
1867                 goto error;
1868         }
1869
1870         trans = btrfs_start_transaction(root, 0);
1871         if (IS_ERR(trans)) {
1872                 rcu_string_free(device->name);
1873                 kfree(device);
1874                 ret = PTR_ERR(trans);
1875                 goto error;
1876         }
1877
1878         lock_chunks(root);
1879
1880         q = bdev_get_queue(bdev);
1881         if (blk_queue_discard(q))
1882                 device->can_discard = 1;
1883         device->writeable = 1;
1884         device->work.func = pending_bios_fn;
1885         generate_random_uuid(device->uuid);
1886         spin_lock_init(&device->io_lock);
1887         device->generation = trans->transid;
1888         device->io_width = root->sectorsize;
1889         device->io_align = root->sectorsize;
1890         device->sector_size = root->sectorsize;
1891         device->total_bytes = i_size_read(bdev->bd_inode);
1892         device->disk_total_bytes = device->total_bytes;
1893         device->dev_root = root->fs_info->dev_root;
1894         device->bdev = bdev;
1895         device->in_fs_metadata = 1;
1896         device->is_tgtdev_for_dev_replace = 0;
1897         device->mode = FMODE_EXCL;
1898         set_blocksize(device->bdev, 4096);
1899
1900         if (seeding_dev) {
1901                 sb->s_flags &= ~MS_RDONLY;
1902                 ret = btrfs_prepare_sprout(root);
1903                 BUG_ON(ret); /* -ENOMEM */
1904         }
1905
1906         device->fs_devices = root->fs_info->fs_devices;
1907
1908         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1909         list_add_rcu(&device->dev_list, &root->fs_info->fs_devices->devices);
1910         list_add(&device->dev_alloc_list,
1911                  &root->fs_info->fs_devices->alloc_list);
1912         root->fs_info->fs_devices->num_devices++;
1913         root->fs_info->fs_devices->open_devices++;
1914         root->fs_info->fs_devices->rw_devices++;
1915         root->fs_info->fs_devices->total_devices++;
1916         if (device->can_discard)
1917                 root->fs_info->fs_devices->num_can_discard++;
1918         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
1919
1920         spin_lock(&root->fs_info->free_chunk_lock);
1921         root->fs_info->free_chunk_space += device->total_bytes;
1922         spin_unlock(&root->fs_info->free_chunk_lock);
1923
1924         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
1925                 root->fs_info->fs_devices->rotating = 1;
1926
1927         total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
1928         btrfs_set_super_total_bytes(root->fs_info->super_copy,
1929                                     total_bytes + device->total_bytes);
1930
1931         total_bytes = btrfs_super_num_devices(root->fs_info->super_copy);
1932         btrfs_set_super_num_devices(root->fs_info->super_copy,
1933                                     total_bytes + 1);
1934         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1935
1936         if (seeding_dev) {
1937                 ret = init_first_rw_device(trans, root, device);
1938                 if (ret) {
1939                         btrfs_abort_transaction(trans, root, ret);
1940                         goto error_trans;
1941                 }
1942                 ret = btrfs_finish_sprout(trans, root);
1943                 if (ret) {
1944                         btrfs_abort_transaction(trans, root, ret);
1945                         goto error_trans;
1946                 }
1947         } else {
1948                 ret = btrfs_add_device(trans, root, device);
1949                 if (ret) {
1950                         btrfs_abort_transaction(trans, root, ret);
1951                         goto error_trans;
1952                 }
1953         }
1954
1955         /*
1956          * we've got more storage, clear any full flags on the space
1957          * infos
1958          */
1959         btrfs_clear_space_info_full(root->fs_info);
1960
1961         unlock_chunks(root);
1962         root->fs_info->num_tolerated_disk_barrier_failures =
1963                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1964         ret = btrfs_commit_transaction(trans, root);
1965
1966         if (seeding_dev) {
1967                 mutex_unlock(&uuid_mutex);
1968                 up_write(&sb->s_umount);
1969
1970                 if (ret) /* transaction commit */
1971                         return ret;
1972
1973                 ret = btrfs_relocate_sys_chunks(root);
1974                 if (ret < 0)
1975                         btrfs_error(root->fs_info, ret,
1976                                     "Failed to relocate sys chunks after "
1977                                     "device initialization. This can be fixed "
1978                                     "using the \"btrfs balance\" command.");
1979                 trans = btrfs_attach_transaction(root);
1980                 if (IS_ERR(trans)) {
1981                         if (PTR_ERR(trans) == -ENOENT)
1982                                 return 0;
1983                         return PTR_ERR(trans);
1984                 }
1985                 ret = btrfs_commit_transaction(trans, root);
1986         }
1987
1988         return ret;
1989
1990 error_trans:
1991         unlock_chunks(root);
1992         btrfs_end_transaction(trans, root);
1993         rcu_string_free(device->name);
1994         kfree(device);
1995 error:
1996         blkdev_put(bdev, FMODE_EXCL);
1997         if (seeding_dev) {
1998                 mutex_unlock(&uuid_mutex);
1999                 up_write(&sb->s_umount);
2000         }
2001         return ret;
2002 }
2003
2004 int btrfs_init_dev_replace_tgtdev(struct btrfs_root *root, char *device_path,
2005                                   struct btrfs_device **device_out)
2006 {
2007         struct request_queue *q;
2008         struct btrfs_device *device;
2009         struct block_device *bdev;
2010         struct btrfs_fs_info *fs_info = root->fs_info;
2011         struct list_head *devices;
2012         struct rcu_string *name;
2013         int ret = 0;
2014
2015         *device_out = NULL;
2016         if (fs_info->fs_devices->seeding)
2017                 return -EINVAL;
2018
2019         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
2020                                   fs_info->bdev_holder);
2021         if (IS_ERR(bdev))
2022                 return PTR_ERR(bdev);
2023
2024         filemap_write_and_wait(bdev->bd_inode->i_mapping);
2025
2026         devices = &fs_info->fs_devices->devices;
2027         list_for_each_entry(device, devices, dev_list) {
2028                 if (device->bdev == bdev) {
2029                         ret = -EEXIST;
2030                         goto error;
2031                 }
2032         }
2033
2034         device = kzalloc(sizeof(*device), GFP_NOFS);
2035         if (!device) {
2036                 ret = -ENOMEM;
2037                 goto error;
2038         }
2039
2040         name = rcu_string_strdup(device_path, GFP_NOFS);
2041         if (!name) {
2042                 kfree(device);
2043                 ret = -ENOMEM;
2044                 goto error;
2045         }
2046         rcu_assign_pointer(device->name, name);
2047
2048         q = bdev_get_queue(bdev);
2049         if (blk_queue_discard(q))
2050                 device->can_discard = 1;
2051         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2052         device->writeable = 1;
2053         device->work.func = pending_bios_fn;
2054         generate_random_uuid(device->uuid);
2055         device->devid = BTRFS_DEV_REPLACE_DEVID;
2056         spin_lock_init(&device->io_lock);
2057         device->generation = 0;
2058         device->io_width = root->sectorsize;
2059         device->io_align = root->sectorsize;
2060         device->sector_size = root->sectorsize;
2061         device->total_bytes = i_size_read(bdev->bd_inode);
2062         device->disk_total_bytes = device->total_bytes;
2063         device->dev_root = fs_info->dev_root;
2064         device->bdev = bdev;
2065         device->in_fs_metadata = 1;
2066         device->is_tgtdev_for_dev_replace = 1;
2067         device->mode = FMODE_EXCL;
2068         set_blocksize(device->bdev, 4096);
2069         device->fs_devices = fs_info->fs_devices;
2070         list_add(&device->dev_list, &fs_info->fs_devices->devices);
2071         fs_info->fs_devices->num_devices++;
2072         fs_info->fs_devices->open_devices++;
2073         if (device->can_discard)
2074                 fs_info->fs_devices->num_can_discard++;
2075         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2076
2077         *device_out = device;
2078         return ret;
2079
2080 error:
2081         blkdev_put(bdev, FMODE_EXCL);
2082         return ret;
2083 }
2084
2085 void btrfs_init_dev_replace_tgtdev_for_resume(struct btrfs_fs_info *fs_info,
2086                                               struct btrfs_device *tgtdev)
2087 {
2088         WARN_ON(fs_info->fs_devices->rw_devices == 0);
2089         tgtdev->io_width = fs_info->dev_root->sectorsize;
2090         tgtdev->io_align = fs_info->dev_root->sectorsize;
2091         tgtdev->sector_size = fs_info->dev_root->sectorsize;
2092         tgtdev->dev_root = fs_info->dev_root;
2093         tgtdev->in_fs_metadata = 1;
2094 }
2095
2096 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
2097                                         struct btrfs_device *device)
2098 {
2099         int ret;
2100         struct btrfs_path *path;
2101         struct btrfs_root *root;
2102         struct btrfs_dev_item *dev_item;
2103         struct extent_buffer *leaf;
2104         struct btrfs_key key;
2105
2106         root = device->dev_root->fs_info->chunk_root;
2107
2108         path = btrfs_alloc_path();
2109         if (!path)
2110                 return -ENOMEM;
2111
2112         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2113         key.type = BTRFS_DEV_ITEM_KEY;
2114         key.offset = device->devid;
2115
2116         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2117         if (ret < 0)
2118                 goto out;
2119
2120         if (ret > 0) {
2121                 ret = -ENOENT;
2122                 goto out;
2123         }
2124
2125         leaf = path->nodes[0];
2126         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
2127
2128         btrfs_set_device_id(leaf, dev_item, device->devid);
2129         btrfs_set_device_type(leaf, dev_item, device->type);
2130         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
2131         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
2132         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
2133         btrfs_set_device_total_bytes(leaf, dev_item, device->disk_total_bytes);
2134         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
2135         btrfs_mark_buffer_dirty(leaf);
2136
2137 out:
2138         btrfs_free_path(path);
2139         return ret;
2140 }
2141
2142 static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
2143                       struct btrfs_device *device, u64 new_size)
2144 {
2145         struct btrfs_super_block *super_copy =
2146                 device->dev_root->fs_info->super_copy;
2147         u64 old_total = btrfs_super_total_bytes(super_copy);
2148         u64 diff = new_size - device->total_bytes;
2149
2150         if (!device->writeable)
2151                 return -EACCES;
2152         if (new_size <= device->total_bytes ||
2153             device->is_tgtdev_for_dev_replace)
2154                 return -EINVAL;
2155
2156         btrfs_set_super_total_bytes(super_copy, old_total + diff);
2157         device->fs_devices->total_rw_bytes += diff;
2158
2159         device->total_bytes = new_size;
2160         device->disk_total_bytes = new_size;
2161         btrfs_clear_space_info_full(device->dev_root->fs_info);
2162
2163         return btrfs_update_device(trans, device);
2164 }
2165
2166 int btrfs_grow_device(struct btrfs_trans_handle *trans,
2167                       struct btrfs_device *device, u64 new_size)
2168 {
2169         int ret;
2170         lock_chunks(device->dev_root);
2171         ret = __btrfs_grow_device(trans, device, new_size);
2172         unlock_chunks(device->dev_root);
2173         return ret;
2174 }
2175
2176 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
2177                             struct btrfs_root *root,
2178                             u64 chunk_tree, u64 chunk_objectid,
2179                             u64 chunk_offset)
2180 {
2181         int ret;
2182         struct btrfs_path *path;
2183         struct btrfs_key key;
2184
2185         root = root->fs_info->chunk_root;
2186         path = btrfs_alloc_path();
2187         if (!path)
2188                 return -ENOMEM;
2189
2190         key.objectid = chunk_objectid;
2191         key.offset = chunk_offset;
2192         key.type = BTRFS_CHUNK_ITEM_KEY;
2193
2194         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2195         if (ret < 0)
2196                 goto out;
2197         else if (ret > 0) { /* Logic error or corruption */
2198                 btrfs_error(root->fs_info, -ENOENT,
2199                             "Failed lookup while freeing chunk.");
2200                 ret = -ENOENT;
2201                 goto out;
2202         }
2203
2204         ret = btrfs_del_item(trans, root, path);
2205         if (ret < 0)
2206                 btrfs_error(root->fs_info, ret,
2207                             "Failed to delete chunk item.");
2208 out:
2209         btrfs_free_path(path);
2210         return ret;
2211 }
2212
2213 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
2214                         chunk_offset)
2215 {
2216         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
2217         struct btrfs_disk_key *disk_key;
2218         struct btrfs_chunk *chunk;
2219         u8 *ptr;
2220         int ret = 0;
2221         u32 num_stripes;
2222         u32 array_size;
2223         u32 len = 0;
2224         u32 cur;
2225         struct btrfs_key key;
2226
2227         array_size = btrfs_super_sys_array_size(super_copy);
2228
2229         ptr = super_copy->sys_chunk_array;
2230         cur = 0;
2231
2232         while (cur < array_size) {
2233                 disk_key = (struct btrfs_disk_key *)ptr;
2234                 btrfs_disk_key_to_cpu(&key, disk_key);
2235
2236                 len = sizeof(*disk_key);
2237
2238                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
2239                         chunk = (struct btrfs_chunk *)(ptr + len);
2240                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
2241                         len += btrfs_chunk_item_size(num_stripes);
2242                 } else {
2243                         ret = -EIO;
2244                         break;
2245                 }
2246                 if (key.objectid == chunk_objectid &&
2247                     key.offset == chunk_offset) {
2248                         memmove(ptr, ptr + len, array_size - (cur + len));
2249                         array_size -= len;
2250                         btrfs_set_super_sys_array_size(super_copy, array_size);
2251                 } else {
2252                         ptr += len;
2253                         cur += len;
2254                 }
2255         }
2256         return ret;
2257 }
2258
2259 static int btrfs_relocate_chunk(struct btrfs_root *root,
2260                          u64 chunk_tree, u64 chunk_objectid,
2261                          u64 chunk_offset)
2262 {
2263         struct extent_map_tree *em_tree;
2264         struct btrfs_root *extent_root;
2265         struct btrfs_trans_handle *trans;
2266         struct extent_map *em;
2267         struct map_lookup *map;
2268         int ret;
2269         int i;
2270
2271         root = root->fs_info->chunk_root;
2272         extent_root = root->fs_info->extent_root;
2273         em_tree = &root->fs_info->mapping_tree.map_tree;
2274
2275         ret = btrfs_can_relocate(extent_root, chunk_offset);
2276         if (ret)
2277                 return -ENOSPC;
2278
2279         /* step one, relocate all the extents inside this chunk */
2280         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
2281         if (ret)
2282                 return ret;
2283
2284         trans = btrfs_start_transaction(root, 0);
2285         BUG_ON(IS_ERR(trans));
2286
2287         lock_chunks(root);
2288
2289         /*
2290          * step two, delete the device extents and the
2291          * chunk tree entries
2292          */
2293         read_lock(&em_tree->lock);
2294         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
2295         read_unlock(&em_tree->lock);
2296
2297         BUG_ON(!em || em->start > chunk_offset ||
2298                em->start + em->len < chunk_offset);
2299         map = (struct map_lookup *)em->bdev;
2300
2301         for (i = 0; i < map->num_stripes; i++) {
2302                 ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
2303                                             map->stripes[i].physical);
2304                 BUG_ON(ret);
2305
2306                 if (map->stripes[i].dev) {
2307                         ret = btrfs_update_device(trans, map->stripes[i].dev);
2308                         BUG_ON(ret);
2309                 }
2310         }
2311         ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
2312                                chunk_offset);
2313
2314         BUG_ON(ret);
2315
2316         trace_btrfs_chunk_free(root, map, chunk_offset, em->len);
2317
2318         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2319                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
2320                 BUG_ON(ret);
2321         }
2322
2323         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
2324         BUG_ON(ret);
2325
2326         write_lock(&em_tree->lock);
2327         remove_extent_mapping(em_tree, em);
2328         write_unlock(&em_tree->lock);
2329
2330         kfree(map);
2331         em->bdev = NULL;
2332
2333         /* once for the tree */
2334         free_extent_map(em);
2335         /* once for us */
2336         free_extent_map(em);
2337
2338         unlock_chunks(root);
2339         btrfs_end_transaction(trans, root);
2340         return 0;
2341 }
2342
2343 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
2344 {
2345         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
2346         struct btrfs_path *path;
2347         struct extent_buffer *leaf;
2348         struct btrfs_chunk *chunk;
2349         struct btrfs_key key;
2350         struct btrfs_key found_key;
2351         u64 chunk_tree = chunk_root->root_key.objectid;
2352         u64 chunk_type;
2353         bool retried = false;
2354         int failed = 0;
2355         int ret;
2356
2357         path = btrfs_alloc_path();
2358         if (!path)
2359                 return -ENOMEM;
2360
2361 again:
2362         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2363         key.offset = (u64)-1;
2364         key.type = BTRFS_CHUNK_ITEM_KEY;
2365
2366         while (1) {
2367                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2368                 if (ret < 0)
2369                         goto error;
2370                 BUG_ON(ret == 0); /* Corruption */
2371
2372                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
2373                                           key.type);
2374                 if (ret < 0)
2375                         goto error;
2376                 if (ret > 0)
2377                         break;
2378
2379                 leaf = path->nodes[0];
2380                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2381
2382                 chunk = btrfs_item_ptr(leaf, path->slots[0],
2383                                        struct btrfs_chunk);
2384                 chunk_type = btrfs_chunk_type(leaf, chunk);
2385                 btrfs_release_path(path);
2386
2387                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
2388                         ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
2389                                                    found_key.objectid,
2390                                                    found_key.offset);
2391                         if (ret == -ENOSPC)
2392                                 failed++;
2393                         else if (ret)
2394                                 BUG();
2395                 }
2396
2397                 if (found_key.offset == 0)
2398                         break;
2399                 key.offset = found_key.offset - 1;
2400         }
2401         ret = 0;
2402         if (failed && !retried) {
2403                 failed = 0;
2404                 retried = true;
2405                 goto again;
2406         } else if (failed && retried) {
2407                 WARN_ON(1);
2408                 ret = -ENOSPC;
2409         }
2410 error:
2411         btrfs_free_path(path);
2412         return ret;
2413 }
2414
2415 static int insert_balance_item(struct btrfs_root *root,
2416                                struct btrfs_balance_control *bctl)
2417 {
2418         struct btrfs_trans_handle *trans;
2419         struct btrfs_balance_item *item;
2420         struct btrfs_disk_balance_args disk_bargs;
2421         struct btrfs_path *path;
2422         struct extent_buffer *leaf;
2423         struct btrfs_key key;
2424         int ret, err;
2425
2426         path = btrfs_alloc_path();
2427         if (!path)
2428                 return -ENOMEM;
2429
2430         trans = btrfs_start_transaction(root, 0);
2431         if (IS_ERR(trans)) {
2432                 btrfs_free_path(path);
2433                 return PTR_ERR(trans);
2434         }
2435
2436         key.objectid = BTRFS_BALANCE_OBJECTID;
2437         key.type = BTRFS_BALANCE_ITEM_KEY;
2438         key.offset = 0;
2439
2440         ret = btrfs_insert_empty_item(trans, root, path, &key,
2441                                       sizeof(*item));
2442         if (ret)
2443                 goto out;
2444
2445         leaf = path->nodes[0];
2446         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
2447
2448         memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
2449
2450         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->data);
2451         btrfs_set_balance_data(leaf, item, &disk_bargs);
2452         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->meta);
2453         btrfs_set_balance_meta(leaf, item, &disk_bargs);
2454         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->sys);
2455         btrfs_set_balance_sys(leaf, item, &disk_bargs);
2456
2457         btrfs_set_balance_flags(leaf, item, bctl->flags);
2458
2459         btrfs_mark_buffer_dirty(leaf);
2460 out:
2461         btrfs_free_path(path);
2462         err = btrfs_commit_transaction(trans, root);
2463         if (err && !ret)
2464                 ret = err;
2465         return ret;
2466 }
2467
2468 static int del_balance_item(struct btrfs_root *root)
2469 {
2470         struct btrfs_trans_handle *trans;
2471         struct btrfs_path *path;
2472         struct btrfs_key key;
2473         int ret, err;
2474
2475         path = btrfs_alloc_path();
2476         if (!path)
2477                 return -ENOMEM;
2478
2479         trans = btrfs_start_transaction(root, 0);
2480         if (IS_ERR(trans)) {
2481                 btrfs_free_path(path);
2482                 return PTR_ERR(trans);
2483         }
2484
2485         key.objectid = BTRFS_BALANCE_OBJECTID;
2486         key.type = BTRFS_BALANCE_ITEM_KEY;
2487         key.offset = 0;
2488
2489         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2490         if (ret < 0)
2491                 goto out;
2492         if (ret > 0) {
2493                 ret = -ENOENT;
2494                 goto out;
2495         }
2496
2497         ret = btrfs_del_item(trans, root, path);
2498 out:
2499         btrfs_free_path(path);
2500         err = btrfs_commit_transaction(trans, root);
2501         if (err && !ret)
2502                 ret = err;
2503         return ret;
2504 }
2505
2506 /*
2507  * This is a heuristic used to reduce the number of chunks balanced on
2508  * resume after balance was interrupted.
2509  */
2510 static void update_balance_args(struct btrfs_balance_control *bctl)
2511 {
2512         /*
2513          * Turn on soft mode for chunk types that were being converted.
2514          */
2515         if (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)
2516                 bctl->data.flags |= BTRFS_BALANCE_ARGS_SOFT;
2517         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)
2518                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_SOFT;
2519         if (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)
2520                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_SOFT;
2521
2522         /*
2523          * Turn on usage filter if is not already used.  The idea is
2524          * that chunks that we have already balanced should be
2525          * reasonably full.  Don't do it for chunks that are being
2526          * converted - that will keep us from relocating unconverted
2527          * (albeit full) chunks.
2528          */
2529         if (!(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2530             !(bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2531                 bctl->data.flags |= BTRFS_BALANCE_ARGS_USAGE;
2532                 bctl->data.usage = 90;
2533         }
2534         if (!(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2535             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2536                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_USAGE;
2537                 bctl->sys.usage = 90;
2538         }
2539         if (!(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2540             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2541                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_USAGE;
2542                 bctl->meta.usage = 90;
2543         }
2544 }
2545
2546 /*
2547  * Should be called with both balance and volume mutexes held to
2548  * serialize other volume operations (add_dev/rm_dev/resize) with
2549  * restriper.  Same goes for unset_balance_control.
2550  */
2551 static void set_balance_control(struct btrfs_balance_control *bctl)
2552 {
2553         struct btrfs_fs_info *fs_info = bctl->fs_info;
2554
2555         BUG_ON(fs_info->balance_ctl);
2556
2557         spin_lock(&fs_info->balance_lock);
2558         fs_info->balance_ctl = bctl;
2559         spin_unlock(&fs_info->balance_lock);
2560 }
2561
2562 static void unset_balance_control(struct btrfs_fs_info *fs_info)
2563 {
2564         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2565
2566         BUG_ON(!fs_info->balance_ctl);
2567
2568         spin_lock(&fs_info->balance_lock);
2569         fs_info->balance_ctl = NULL;
2570         spin_unlock(&fs_info->balance_lock);
2571
2572         kfree(bctl);
2573 }
2574
2575 /*
2576  * Balance filters.  Return 1 if chunk should be filtered out
2577  * (should not be balanced).
2578  */
2579 static int chunk_profiles_filter(u64 chunk_type,
2580                                  struct btrfs_balance_args *bargs)
2581 {
2582         chunk_type = chunk_to_extended(chunk_type) &
2583                                 BTRFS_EXTENDED_PROFILE_MASK;
2584
2585         if (bargs->profiles & chunk_type)
2586                 return 0;
2587
2588         return 1;
2589 }
2590
2591 static int chunk_usage_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
2592                               struct btrfs_balance_args *bargs)
2593 {
2594         struct btrfs_block_group_cache *cache;
2595         u64 chunk_used, user_thresh;
2596         int ret = 1;
2597
2598         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
2599         chunk_used = btrfs_block_group_used(&cache->item);
2600
2601         user_thresh = div_factor_fine(cache->key.offset, bargs->usage);
2602         if (chunk_used < user_thresh)
2603                 ret = 0;
2604
2605         btrfs_put_block_group(cache);
2606         return ret;
2607 }
2608
2609 static int chunk_devid_filter(struct extent_buffer *leaf,
2610                               struct btrfs_chunk *chunk,
2611                               struct btrfs_balance_args *bargs)
2612 {
2613         struct btrfs_stripe *stripe;
2614         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2615         int i;
2616
2617         for (i = 0; i < num_stripes; i++) {
2618                 stripe = btrfs_stripe_nr(chunk, i);
2619                 if (btrfs_stripe_devid(leaf, stripe) == bargs->devid)
2620                         return 0;
2621         }
2622
2623         return 1;
2624 }
2625
2626 /* [pstart, pend) */
2627 static int chunk_drange_filter(struct extent_buffer *leaf,
2628                                struct btrfs_chunk *chunk,
2629                                u64 chunk_offset,
2630                                struct btrfs_balance_args *bargs)
2631 {
2632         struct btrfs_stripe *stripe;
2633         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2634         u64 stripe_offset;
2635         u64 stripe_length;
2636         int factor;
2637         int i;
2638
2639         if (!(bargs->flags & BTRFS_BALANCE_ARGS_DEVID))
2640                 return 0;
2641
2642         if (btrfs_chunk_type(leaf, chunk) & (BTRFS_BLOCK_GROUP_DUP |
2643              BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10))
2644                 factor = 2;
2645         else
2646                 factor = 1;
2647         factor = num_stripes / factor;
2648
2649         for (i = 0; i < num_stripes; i++) {
2650                 stripe = btrfs_stripe_nr(chunk, i);
2651                 if (btrfs_stripe_devid(leaf, stripe) != bargs->devid)
2652                         continue;
2653
2654                 stripe_offset = btrfs_stripe_offset(leaf, stripe);
2655                 stripe_length = btrfs_chunk_length(leaf, chunk);
2656                 do_div(stripe_length, factor);
2657
2658                 if (stripe_offset < bargs->pend &&
2659                     stripe_offset + stripe_length > bargs->pstart)
2660                         return 0;
2661         }
2662
2663         return 1;
2664 }
2665
2666 /* [vstart, vend) */
2667 static int chunk_vrange_filter(struct extent_buffer *leaf,
2668                                struct btrfs_chunk *chunk,
2669                                u64 chunk_offset,
2670                                struct btrfs_balance_args *bargs)
2671 {
2672         if (chunk_offset < bargs->vend &&
2673             chunk_offset + btrfs_chunk_length(leaf, chunk) > bargs->vstart)
2674                 /* at least part of the chunk is inside this vrange */
2675                 return 0;
2676
2677         return 1;
2678 }
2679
2680 static int chunk_soft_convert_filter(u64 chunk_type,
2681                                      struct btrfs_balance_args *bargs)
2682 {
2683         if (!(bargs->flags & BTRFS_BALANCE_ARGS_CONVERT))
2684                 return 0;
2685
2686         chunk_type = chunk_to_extended(chunk_type) &
2687                                 BTRFS_EXTENDED_PROFILE_MASK;
2688
2689         if (bargs->target == chunk_type)
2690                 return 1;
2691
2692         return 0;
2693 }
2694
2695 static int should_balance_chunk(struct btrfs_root *root,
2696                                 struct extent_buffer *leaf,
2697                                 struct btrfs_chunk *chunk, u64 chunk_offset)
2698 {
2699         struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
2700         struct btrfs_balance_args *bargs = NULL;
2701         u64 chunk_type = btrfs_chunk_type(leaf, chunk);
2702
2703         /* type filter */
2704         if (!((chunk_type & BTRFS_BLOCK_GROUP_TYPE_MASK) &
2705               (bctl->flags & BTRFS_BALANCE_TYPE_MASK))) {
2706                 return 0;
2707         }
2708
2709         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
2710                 bargs = &bctl->data;
2711         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
2712                 bargs = &bctl->sys;
2713         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
2714                 bargs = &bctl->meta;
2715
2716         /* profiles filter */
2717         if ((bargs->flags & BTRFS_BALANCE_ARGS_PROFILES) &&
2718             chunk_profiles_filter(chunk_type, bargs)) {
2719                 return 0;
2720         }
2721
2722         /* usage filter */
2723         if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
2724             chunk_usage_filter(bctl->fs_info, chunk_offset, bargs)) {
2725                 return 0;
2726         }
2727
2728         /* devid filter */
2729         if ((bargs->flags & BTRFS_BALANCE_ARGS_DEVID) &&
2730             chunk_devid_filter(leaf, chunk, bargs)) {
2731                 return 0;
2732         }
2733
2734         /* drange filter, makes sense only with devid filter */
2735         if ((bargs->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
2736             chunk_drange_filter(leaf, chunk, chunk_offset, bargs)) {
2737                 return 0;
2738         }
2739
2740         /* vrange filter */
2741         if ((bargs->flags & BTRFS_BALANCE_ARGS_VRANGE) &&
2742             chunk_vrange_filter(leaf, chunk, chunk_offset, bargs)) {
2743                 return 0;
2744         }
2745
2746         /* soft profile changing mode */
2747         if ((bargs->flags & BTRFS_BALANCE_ARGS_SOFT) &&
2748             chunk_soft_convert_filter(chunk_type, bargs)) {
2749                 return 0;
2750         }
2751
2752         return 1;
2753 }
2754
2755 static int __btrfs_balance(struct btrfs_fs_info *fs_info)
2756 {
2757         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2758         struct btrfs_root *chunk_root = fs_info->chunk_root;
2759         struct btrfs_root *dev_root = fs_info->dev_root;
2760         struct list_head *devices;
2761         struct btrfs_device *device;
2762         u64 old_size;
2763         u64 size_to_free;
2764         struct btrfs_chunk *chunk;
2765         struct btrfs_path *path;
2766         struct btrfs_key key;
2767         struct btrfs_key found_key;
2768         struct btrfs_trans_handle *trans;
2769         struct extent_buffer *leaf;
2770         int slot;
2771         int ret;
2772         int enospc_errors = 0;
2773         bool counting = true;
2774
2775         /* step one make some room on all the devices */
2776         devices = &fs_info->fs_devices->devices;
2777         list_for_each_entry(device, devices, dev_list) {
2778                 old_size = device->total_bytes;
2779                 size_to_free = div_factor(old_size, 1);
2780                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
2781                 if (!device->writeable ||
2782                     device->total_bytes - device->bytes_used > size_to_free ||
2783                     device->is_tgtdev_for_dev_replace)
2784                         continue;
2785
2786                 ret = btrfs_shrink_device(device, old_size - size_to_free);
2787                 if (ret == -ENOSPC)
2788                         break;
2789                 BUG_ON(ret);
2790
2791                 trans = btrfs_start_transaction(dev_root, 0);
2792                 BUG_ON(IS_ERR(trans));
2793
2794                 ret = btrfs_grow_device(trans, device, old_size);
2795                 BUG_ON(ret);
2796
2797                 btrfs_end_transaction(trans, dev_root);
2798         }
2799
2800         /* step two, relocate all the chunks */
2801         path = btrfs_alloc_path();
2802         if (!path) {
2803                 ret = -ENOMEM;
2804                 goto error;
2805         }
2806
2807         /* zero out stat counters */
2808         spin_lock(&fs_info->balance_lock);
2809         memset(&bctl->stat, 0, sizeof(bctl->stat));
2810         spin_unlock(&fs_info->balance_lock);
2811 again:
2812         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2813         key.offset = (u64)-1;
2814         key.type = BTRFS_CHUNK_ITEM_KEY;
2815
2816         while (1) {
2817                 if ((!counting && atomic_read(&fs_info->balance_pause_req)) ||
2818                     atomic_read(&fs_info->balance_cancel_req)) {
2819                         ret = -ECANCELED;
2820                         goto error;
2821                 }
2822
2823                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2824                 if (ret < 0)
2825                         goto error;
2826
2827                 /*
2828                  * this shouldn't happen, it means the last relocate
2829                  * failed
2830                  */
2831                 if (ret == 0)
2832                         BUG(); /* FIXME break ? */
2833
2834                 ret = btrfs_previous_item(chunk_root, path, 0,
2835                                           BTRFS_CHUNK_ITEM_KEY);
2836                 if (ret) {
2837                         ret = 0;
2838                         break;
2839                 }
2840
2841                 leaf = path->nodes[0];
2842                 slot = path->slots[0];
2843                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2844
2845                 if (found_key.objectid != key.objectid)
2846                         break;
2847
2848                 /* chunk zero is special */
2849                 if (found_key.offset == 0)
2850                         break;
2851
2852                 chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
2853
2854                 if (!counting) {
2855                         spin_lock(&fs_info->balance_lock);
2856                         bctl->stat.considered++;
2857                         spin_unlock(&fs_info->balance_lock);
2858                 }
2859
2860                 ret = should_balance_chunk(chunk_root, leaf, chunk,
2861                                            found_key.offset);
2862                 btrfs_release_path(path);
2863                 if (!ret)
2864                         goto loop;
2865
2866                 if (counting) {
2867                         spin_lock(&fs_info->balance_lock);
2868                         bctl->stat.expected++;
2869                         spin_unlock(&fs_info->balance_lock);
2870                         goto loop;
2871                 }
2872
2873                 ret = btrfs_relocate_chunk(chunk_root,
2874                                            chunk_root->root_key.objectid,
2875                                            found_key.objectid,
2876                                            found_key.offset);
2877                 if (ret && ret != -ENOSPC)
2878                         goto error;
2879                 if (ret == -ENOSPC) {
2880                         enospc_errors++;
2881                 } else {
2882                         spin_lock(&fs_info->balance_lock);
2883                         bctl->stat.completed++;
2884                         spin_unlock(&fs_info->balance_lock);
2885                 }
2886 loop:
2887                 key.offset = found_key.offset - 1;
2888         }
2889
2890         if (counting) {
2891                 btrfs_release_path(path);
2892                 counting = false;
2893                 goto again;
2894         }
2895 error:
2896         btrfs_free_path(path);
2897         if (enospc_errors) {
2898                 printk(KERN_INFO "btrfs: %d enospc errors during balance\n",
2899                        enospc_errors);
2900                 if (!ret)
2901                         ret = -ENOSPC;
2902         }
2903
2904         return ret;
2905 }
2906
2907 /**
2908  * alloc_profile_is_valid - see if a given profile is valid and reduced
2909  * @flags: profile to validate
2910  * @extended: if true @flags is treated as an extended profile
2911  */
2912 static int alloc_profile_is_valid(u64 flags, int extended)
2913 {
2914         u64 mask = (extended ? BTRFS_EXTENDED_PROFILE_MASK :
2915                                BTRFS_BLOCK_GROUP_PROFILE_MASK);
2916
2917         flags &= ~BTRFS_BLOCK_GROUP_TYPE_MASK;
2918
2919         /* 1) check that all other bits are zeroed */
2920         if (flags & ~mask)
2921                 return 0;
2922
2923         /* 2) see if profile is reduced */
2924         if (flags == 0)
2925                 return !extended; /* "0" is valid for usual profiles */
2926
2927         /* true if exactly one bit set */
2928         return (flags & (flags - 1)) == 0;
2929 }
2930
2931 static inline int balance_need_close(struct btrfs_fs_info *fs_info)
2932 {
2933         /* cancel requested || normal exit path */
2934         return atomic_read(&fs_info->balance_cancel_req) ||
2935                 (atomic_read(&fs_info->balance_pause_req) == 0 &&
2936                  atomic_read(&fs_info->balance_cancel_req) == 0);
2937 }
2938
2939 static void __cancel_balance(struct btrfs_fs_info *fs_info)
2940 {
2941         int ret;
2942
2943         unset_balance_control(fs_info);
2944         ret = del_balance_item(fs_info->tree_root);
2945         BUG_ON(ret);
2946 }
2947
2948 void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
2949                                struct btrfs_ioctl_balance_args *bargs);
2950
2951 /*
2952  * Should be called with both balance and volume mutexes held
2953  */
2954 int btrfs_balance(struct btrfs_balance_control *bctl,
2955                   struct btrfs_ioctl_balance_args *bargs)
2956 {
2957         struct btrfs_fs_info *fs_info = bctl->fs_info;
2958         u64 allowed;
2959         int mixed = 0;
2960         int ret;
2961         u64 num_devices;
2962
2963         if (btrfs_fs_closing(fs_info) ||
2964             atomic_read(&fs_info->balance_pause_req) ||
2965             atomic_read(&fs_info->balance_cancel_req)) {
2966                 ret = -EINVAL;
2967                 goto out;
2968         }
2969
2970         allowed = btrfs_super_incompat_flags(fs_info->super_copy);
2971         if (allowed & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
2972                 mixed = 1;
2973
2974         /*
2975          * In case of mixed groups both data and meta should be picked,
2976          * and identical options should be given for both of them.
2977          */
2978         allowed = BTRFS_BALANCE_DATA | BTRFS_BALANCE_METADATA;
2979         if (mixed && (bctl->flags & allowed)) {
2980                 if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
2981                     !(bctl->flags & BTRFS_BALANCE_METADATA) ||
2982                     memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
2983                         printk(KERN_ERR "btrfs: with mixed groups data and "
2984                                "metadata balance options must be the same\n");
2985                         ret = -EINVAL;
2986                         goto out;
2987                 }
2988         }
2989
2990         num_devices = fs_info->fs_devices->num_devices;
2991         btrfs_dev_replace_lock(&fs_info->dev_replace);
2992         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) {
2993                 BUG_ON(num_devices < 1);
2994                 num_devices--;
2995         }
2996         btrfs_dev_replace_unlock(&fs_info->dev_replace);
2997         allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
2998         if (num_devices == 1)
2999                 allowed |= BTRFS_BLOCK_GROUP_DUP;
3000         else if (num_devices < 4)
3001                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1);
3002         else
3003                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
3004                                 BTRFS_BLOCK_GROUP_RAID10);
3005
3006         if ((bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3007             (!alloc_profile_is_valid(bctl->data.target, 1) ||
3008              (bctl->data.target & ~allowed))) {
3009                 printk(KERN_ERR "btrfs: unable to start balance with target "
3010                        "data profile %llu\n",
3011                        (unsigned long long)bctl->data.target);
3012                 ret = -EINVAL;
3013                 goto out;
3014         }
3015         if ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3016             (!alloc_profile_is_valid(bctl->meta.target, 1) ||
3017              (bctl->meta.target & ~allowed))) {
3018                 printk(KERN_ERR "btrfs: unable to start balance with target "
3019                        "metadata profile %llu\n",
3020                        (unsigned long long)bctl->meta.target);
3021                 ret = -EINVAL;
3022                 goto out;
3023         }
3024         if ((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3025             (!alloc_profile_is_valid(bctl->sys.target, 1) ||
3026              (bctl->sys.target & ~allowed))) {
3027                 printk(KERN_ERR "btrfs: unable to start balance with target "
3028                        "system profile %llu\n",
3029                        (unsigned long long)bctl->sys.target);
3030                 ret = -EINVAL;
3031                 goto out;
3032         }
3033
3034         /* allow dup'ed data chunks only in mixed mode */
3035         if (!mixed && (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3036             (bctl->data.target & BTRFS_BLOCK_GROUP_DUP)) {
3037                 printk(KERN_ERR "btrfs: dup for data is not allowed\n");
3038                 ret = -EINVAL;
3039                 goto out;
3040         }
3041
3042         /* allow to reduce meta or sys integrity only if force set */
3043         allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3044                         BTRFS_BLOCK_GROUP_RAID10;
3045         if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3046              (fs_info->avail_system_alloc_bits & allowed) &&
3047              !(bctl->sys.target & allowed)) ||
3048             ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3049              (fs_info->avail_metadata_alloc_bits & allowed) &&
3050              !(bctl->meta.target & allowed))) {
3051                 if (bctl->flags & BTRFS_BALANCE_FORCE) {
3052                         printk(KERN_INFO "btrfs: force reducing metadata "
3053                                "integrity\n");
3054                 } else {
3055                         printk(KERN_ERR "btrfs: balance will reduce metadata "
3056                                "integrity, use force if you want this\n");
3057                         ret = -EINVAL;
3058                         goto out;
3059                 }
3060         }
3061
3062         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3063                 int num_tolerated_disk_barrier_failures;
3064                 u64 target = bctl->sys.target;
3065
3066                 num_tolerated_disk_barrier_failures =
3067                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
3068                 if (num_tolerated_disk_barrier_failures > 0 &&
3069                     (target &
3070                      (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3071                       BTRFS_AVAIL_ALLOC_BIT_SINGLE)))
3072                         num_tolerated_disk_barrier_failures = 0;
3073                 else if (num_tolerated_disk_barrier_failures > 1 &&
3074                          (target &
3075                           (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)))
3076                         num_tolerated_disk_barrier_failures = 1;
3077
3078                 fs_info->num_tolerated_disk_barrier_failures =
3079                         num_tolerated_disk_barrier_failures;
3080         }
3081
3082         ret = insert_balance_item(fs_info->tree_root, bctl);
3083         if (ret && ret != -EEXIST)
3084                 goto out;
3085
3086         if (!(bctl->flags & BTRFS_BALANCE_RESUME)) {
3087                 BUG_ON(ret == -EEXIST);
3088                 set_balance_control(bctl);
3089         } else {
3090                 BUG_ON(ret != -EEXIST);
3091                 spin_lock(&fs_info->balance_lock);
3092                 update_balance_args(bctl);
3093                 spin_unlock(&fs_info->balance_lock);
3094         }
3095
3096         atomic_inc(&fs_info->balance_running);
3097         mutex_unlock(&fs_info->balance_mutex);
3098
3099         ret = __btrfs_balance(fs_info);
3100
3101         mutex_lock(&fs_info->balance_mutex);
3102         atomic_dec(&fs_info->balance_running);
3103
3104         if (bargs) {
3105                 memset(bargs, 0, sizeof(*bargs));
3106                 update_ioctl_balance_args(fs_info, 0, bargs);
3107         }
3108
3109         if ((ret && ret != -ECANCELED && ret != -ENOSPC) ||
3110             balance_need_close(fs_info)) {
3111                 __cancel_balance(fs_info);
3112         }
3113
3114         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3115                 fs_info->num_tolerated_disk_barrier_failures =
3116                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
3117         }
3118
3119         wake_up(&fs_info->balance_wait_q);
3120
3121         return ret;
3122 out:
3123         if (bctl->flags & BTRFS_BALANCE_RESUME)
3124                 __cancel_balance(fs_info);
3125         else
3126                 kfree(bctl);
3127         return ret;
3128 }
3129
3130 static int balance_kthread(void *data)
3131 {
3132         struct btrfs_fs_info *fs_info = data;
3133         int ret = 0;
3134
3135         mutex_lock(&fs_info->volume_mutex);
3136         mutex_lock(&fs_info->balance_mutex);
3137
3138         if (fs_info->balance_ctl) {
3139                 printk(KERN_INFO "btrfs: continuing balance\n");
3140                 ret = btrfs_balance(fs_info->balance_ctl, NULL);
3141         }
3142
3143         atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3144         mutex_unlock(&fs_info->balance_mutex);
3145         mutex_unlock(&fs_info->volume_mutex);
3146
3147         return ret;
3148 }
3149
3150 int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
3151 {
3152         struct task_struct *tsk;
3153
3154         spin_lock(&fs_info->balance_lock);
3155         if (!fs_info->balance_ctl) {
3156                 spin_unlock(&fs_info->balance_lock);
3157                 return 0;
3158         }
3159         spin_unlock(&fs_info->balance_lock);
3160
3161         if (btrfs_test_opt(fs_info->tree_root, SKIP_BALANCE)) {
3162                 printk(KERN_INFO "btrfs: force skipping balance\n");
3163                 return 0;
3164         }
3165
3166         WARN_ON(atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1));
3167         tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance");
3168         if (IS_ERR(tsk))
3169                 return PTR_ERR(tsk);
3170
3171         return 0;
3172 }
3173
3174 int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
3175 {
3176         struct btrfs_balance_control *bctl;
3177         struct btrfs_balance_item *item;
3178         struct btrfs_disk_balance_args disk_bargs;
3179         struct btrfs_path *path;
3180         struct extent_buffer *leaf;
3181         struct btrfs_key key;
3182         int ret;
3183
3184         path = btrfs_alloc_path();
3185         if (!path)
3186                 return -ENOMEM;
3187
3188         key.objectid = BTRFS_BALANCE_OBJECTID;
3189         key.type = BTRFS_BALANCE_ITEM_KEY;
3190         key.offset = 0;
3191
3192         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
3193         if (ret < 0)
3194                 goto out;
3195         if (ret > 0) { /* ret = -ENOENT; */
3196                 ret = 0;
3197                 goto out;
3198         }
3199
3200         bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
3201         if (!bctl) {
3202                 ret = -ENOMEM;
3203                 goto out;
3204         }
3205
3206         leaf = path->nodes[0];
3207         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
3208
3209         bctl->fs_info = fs_info;
3210         bctl->flags = btrfs_balance_flags(leaf, item);
3211         bctl->flags |= BTRFS_BALANCE_RESUME;
3212
3213         btrfs_balance_data(leaf, item, &disk_bargs);
3214         btrfs_disk_balance_args_to_cpu(&bctl->data, &disk_bargs);
3215         btrfs_balance_meta(leaf, item, &disk_bargs);
3216         btrfs_disk_balance_args_to_cpu(&bctl->meta, &disk_bargs);
3217         btrfs_balance_sys(leaf, item, &disk_bargs);
3218         btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
3219
3220         mutex_lock(&fs_info->volume_mutex);
3221         mutex_lock(&fs_info->balance_mutex);
3222
3223         set_balance_control(bctl);
3224
3225         mutex_unlock(&fs_info->balance_mutex);
3226         mutex_unlock(&fs_info->volume_mutex);
3227 out:
3228         btrfs_free_path(path);
3229         return ret;
3230 }
3231
3232 int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
3233 {
3234         int ret = 0;
3235
3236         mutex_lock(&fs_info->balance_mutex);
3237         if (!fs_info->balance_ctl) {
3238                 mutex_unlock(&fs_info->balance_mutex);
3239                 return -ENOTCONN;
3240         }
3241
3242         if (atomic_read(&fs_info->balance_running)) {
3243                 atomic_inc(&fs_info->balance_pause_req);
3244                 mutex_unlock(&fs_info->balance_mutex);
3245
3246                 wait_event(fs_info->balance_wait_q,
3247                            atomic_read(&fs_info->balance_running) == 0);
3248
3249                 mutex_lock(&fs_info->balance_mutex);
3250                 /* we are good with balance_ctl ripped off from under us */
3251                 BUG_ON(atomic_read(&fs_info->balance_running));
3252                 atomic_dec(&fs_info->balance_pause_req);
3253         } else {
3254                 ret = -ENOTCONN;
3255         }
3256
3257         mutex_unlock(&fs_info->balance_mutex);
3258         return ret;
3259 }
3260
3261 int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
3262 {
3263         mutex_lock(&fs_info->balance_mutex);
3264         if (!fs_info->balance_ctl) {
3265                 mutex_unlock(&fs_info->balance_mutex);
3266                 return -ENOTCONN;
3267         }
3268
3269         atomic_inc(&fs_info->balance_cancel_req);
3270         /*
3271          * if we are running just wait and return, balance item is
3272          * deleted in btrfs_balance in this case
3273          */
3274         if (atomic_read(&fs_info->balance_running)) {
3275                 mutex_unlock(&fs_info->balance_mutex);
3276                 wait_event(fs_info->balance_wait_q,
3277                            atomic_read(&fs_info->balance_running) == 0);
3278                 mutex_lock(&fs_info->balance_mutex);
3279         } else {
3280                 /* __cancel_balance needs volume_mutex */
3281                 mutex_unlock(&fs_info->balance_mutex);
3282                 mutex_lock(&fs_info->volume_mutex);
3283                 mutex_lock(&fs_info->balance_mutex);
3284
3285                 if (fs_info->balance_ctl)
3286                         __cancel_balance(fs_info);
3287
3288                 mutex_unlock(&fs_info->volume_mutex);
3289         }
3290
3291         BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));
3292         atomic_dec(&fs_info->balance_cancel_req);
3293         mutex_unlock(&fs_info->balance_mutex);
3294         return 0;
3295 }
3296
3297 /*
3298  * shrinking a device means finding all of the device extents past
3299  * the new size, and then following the back refs to the chunks.
3300  * The chunk relocation code actually frees the device extent
3301  */
3302 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
3303 {
3304         struct btrfs_trans_handle *trans;
3305         struct btrfs_root *root = device->dev_root;
3306         struct btrfs_dev_extent *dev_extent = NULL;
3307         struct btrfs_path *path;
3308         u64 length;
3309         u64 chunk_tree;
3310         u64 chunk_objectid;
3311         u64 chunk_offset;
3312         int ret;
3313         int slot;
3314         int failed = 0;
3315         bool retried = false;
3316         struct extent_buffer *l;
3317         struct btrfs_key key;
3318         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3319         u64 old_total = btrfs_super_total_bytes(super_copy);
3320         u64 old_size = device->total_bytes;
3321         u64 diff = device->total_bytes - new_size;
3322
3323         if (device->is_tgtdev_for_dev_replace)
3324                 return -EINVAL;
3325
3326         path = btrfs_alloc_path();
3327         if (!path)
3328                 return -ENOMEM;
3329
3330         path->reada = 2;
3331
3332         lock_chunks(root);
3333
3334         device->total_bytes = new_size;
3335         if (device->writeable) {
3336                 device->fs_devices->total_rw_bytes -= diff;
3337                 spin_lock(&root->fs_info->free_chunk_lock);
3338                 root->fs_info->free_chunk_space -= diff;
3339                 spin_unlock(&root->fs_info->free_chunk_lock);
3340         }
3341         unlock_chunks(root);
3342
3343 again:
3344         key.objectid = device->devid;
3345         key.offset = (u64)-1;
3346         key.type = BTRFS_DEV_EXTENT_KEY;
3347
3348         do {
3349                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3350                 if (ret < 0)
3351                         goto done;
3352
3353                 ret = btrfs_previous_item(root, path, 0, key.type);
3354                 if (ret < 0)
3355                         goto done;
3356                 if (ret) {
3357                         ret = 0;
3358                         btrfs_release_path(path);
3359                         break;
3360                 }
3361
3362                 l = path->nodes[0];
3363                 slot = path->slots[0];
3364                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);