Btrfs: don't panic if we get an error while balancing V2
[linux-2.6.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 <asm/div64.h>
27 #include "compat.h"
28 #include "ctree.h"
29 #include "extent_map.h"
30 #include "disk-io.h"
31 #include "transaction.h"
32 #include "print-tree.h"
33 #include "volumes.h"
34 #include "async-thread.h"
35
36 static int init_first_rw_device(struct btrfs_trans_handle *trans,
37                                 struct btrfs_root *root,
38                                 struct btrfs_device *device);
39 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
40
41 static DEFINE_MUTEX(uuid_mutex);
42 static LIST_HEAD(fs_uuids);
43
44 static void lock_chunks(struct btrfs_root *root)
45 {
46         mutex_lock(&root->fs_info->chunk_mutex);
47 }
48
49 static void unlock_chunks(struct btrfs_root *root)
50 {
51         mutex_unlock(&root->fs_info->chunk_mutex);
52 }
53
54 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
55 {
56         struct btrfs_device *device;
57         WARN_ON(fs_devices->opened);
58         while (!list_empty(&fs_devices->devices)) {
59                 device = list_entry(fs_devices->devices.next,
60                                     struct btrfs_device, dev_list);
61                 list_del(&device->dev_list);
62                 kfree(device->name);
63                 kfree(device);
64         }
65         kfree(fs_devices);
66 }
67
68 int btrfs_cleanup_fs_uuids(void)
69 {
70         struct btrfs_fs_devices *fs_devices;
71
72         while (!list_empty(&fs_uuids)) {
73                 fs_devices = list_entry(fs_uuids.next,
74                                         struct btrfs_fs_devices, list);
75                 list_del(&fs_devices->list);
76                 free_fs_devices(fs_devices);
77         }
78         return 0;
79 }
80
81 static noinline struct btrfs_device *__find_device(struct list_head *head,
82                                                    u64 devid, u8 *uuid)
83 {
84         struct btrfs_device *dev;
85
86         list_for_each_entry(dev, head, dev_list) {
87                 if (dev->devid == devid &&
88                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
89                         return dev;
90                 }
91         }
92         return NULL;
93 }
94
95 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
96 {
97         struct btrfs_fs_devices *fs_devices;
98
99         list_for_each_entry(fs_devices, &fs_uuids, list) {
100                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
101                         return fs_devices;
102         }
103         return NULL;
104 }
105
106 static void requeue_list(struct btrfs_pending_bios *pending_bios,
107                         struct bio *head, struct bio *tail)
108 {
109
110         struct bio *old_head;
111
112         old_head = pending_bios->head;
113         pending_bios->head = head;
114         if (pending_bios->tail)
115                 tail->bi_next = old_head;
116         else
117                 pending_bios->tail = tail;
118 }
119
120 /*
121  * we try to collect pending bios for a device so we don't get a large
122  * number of procs sending bios down to the same device.  This greatly
123  * improves the schedulers ability to collect and merge the bios.
124  *
125  * But, it also turns into a long list of bios to process and that is sure
126  * to eventually make the worker thread block.  The solution here is to
127  * make some progress and then put this work struct back at the end of
128  * the list if the block device is congested.  This way, multiple devices
129  * can make progress from a single worker thread.
130  */
131 static noinline int run_scheduled_bios(struct btrfs_device *device)
132 {
133         struct bio *pending;
134         struct backing_dev_info *bdi;
135         struct btrfs_fs_info *fs_info;
136         struct btrfs_pending_bios *pending_bios;
137         struct bio *tail;
138         struct bio *cur;
139         int again = 0;
140         unsigned long num_run;
141         unsigned long batch_run = 0;
142         unsigned long limit;
143         unsigned long last_waited = 0;
144         int force_reg = 0;
145         struct blk_plug plug;
146
147         /*
148          * this function runs all the bios we've collected for
149          * a particular device.  We don't want to wander off to
150          * another device without first sending all of these down.
151          * So, setup a plug here and finish it off before we return
152          */
153         blk_start_plug(&plug);
154
155         bdi = blk_get_backing_dev_info(device->bdev);
156         fs_info = device->dev_root->fs_info;
157         limit = btrfs_async_submit_limit(fs_info);
158         limit = limit * 2 / 3;
159
160 loop:
161         spin_lock(&device->io_lock);
162
163 loop_lock:
164         num_run = 0;
165
166         /* take all the bios off the list at once and process them
167          * later on (without the lock held).  But, remember the
168          * tail and other pointers so the bios can be properly reinserted
169          * into the list if we hit congestion
170          */
171         if (!force_reg && device->pending_sync_bios.head) {
172                 pending_bios = &device->pending_sync_bios;
173                 force_reg = 1;
174         } else {
175                 pending_bios = &device->pending_bios;
176                 force_reg = 0;
177         }
178
179         pending = pending_bios->head;
180         tail = pending_bios->tail;
181         WARN_ON(pending && !tail);
182
183         /*
184          * if pending was null this time around, no bios need processing
185          * at all and we can stop.  Otherwise it'll loop back up again
186          * and do an additional check so no bios are missed.
187          *
188          * device->running_pending is used to synchronize with the
189          * schedule_bio code.
190          */
191         if (device->pending_sync_bios.head == NULL &&
192             device->pending_bios.head == NULL) {
193                 again = 0;
194                 device->running_pending = 0;
195         } else {
196                 again = 1;
197                 device->running_pending = 1;
198         }
199
200         pending_bios->head = NULL;
201         pending_bios->tail = NULL;
202
203         spin_unlock(&device->io_lock);
204
205         while (pending) {
206
207                 rmb();
208                 /* we want to work on both lists, but do more bios on the
209                  * sync list than the regular list
210                  */
211                 if ((num_run > 32 &&
212                     pending_bios != &device->pending_sync_bios &&
213                     device->pending_sync_bios.head) ||
214                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
215                     device->pending_bios.head)) {
216                         spin_lock(&device->io_lock);
217                         requeue_list(pending_bios, pending, tail);
218                         goto loop_lock;
219                 }
220
221                 cur = pending;
222                 pending = pending->bi_next;
223                 cur->bi_next = NULL;
224                 atomic_dec(&fs_info->nr_async_bios);
225
226                 if (atomic_read(&fs_info->nr_async_bios) < limit &&
227                     waitqueue_active(&fs_info->async_submit_wait))
228                         wake_up(&fs_info->async_submit_wait);
229
230                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
231
232                 submit_bio(cur->bi_rw, cur);
233                 num_run++;
234                 batch_run++;
235                 if (need_resched())
236                         cond_resched();
237
238                 /*
239                  * we made progress, there is more work to do and the bdi
240                  * is now congested.  Back off and let other work structs
241                  * run instead
242                  */
243                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
244                     fs_info->fs_devices->open_devices > 1) {
245                         struct io_context *ioc;
246
247                         ioc = current->io_context;
248
249                         /*
250                          * the main goal here is that we don't want to
251                          * block if we're going to be able to submit
252                          * more requests without blocking.
253                          *
254                          * This code does two great things, it pokes into
255                          * the elevator code from a filesystem _and_
256                          * it makes assumptions about how batching works.
257                          */
258                         if (ioc && ioc->nr_batch_requests > 0 &&
259                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
260                             (last_waited == 0 ||
261                              ioc->last_waited == last_waited)) {
262                                 /*
263                                  * we want to go through our batch of
264                                  * requests and stop.  So, we copy out
265                                  * the ioc->last_waited time and test
266                                  * against it before looping
267                                  */
268                                 last_waited = ioc->last_waited;
269                                 if (need_resched())
270                                         cond_resched();
271                                 continue;
272                         }
273                         spin_lock(&device->io_lock);
274                         requeue_list(pending_bios, pending, tail);
275                         device->running_pending = 1;
276
277                         spin_unlock(&device->io_lock);
278                         btrfs_requeue_work(&device->work);
279                         goto done;
280                 }
281         }
282
283         cond_resched();
284         if (again)
285                 goto loop;
286
287         spin_lock(&device->io_lock);
288         if (device->pending_bios.head || device->pending_sync_bios.head)
289                 goto loop_lock;
290         spin_unlock(&device->io_lock);
291
292 done:
293         blk_finish_plug(&plug);
294         return 0;
295 }
296
297 static void pending_bios_fn(struct btrfs_work *work)
298 {
299         struct btrfs_device *device;
300
301         device = container_of(work, struct btrfs_device, work);
302         run_scheduled_bios(device);
303 }
304
305 static noinline int device_list_add(const char *path,
306                            struct btrfs_super_block *disk_super,
307                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
308 {
309         struct btrfs_device *device;
310         struct btrfs_fs_devices *fs_devices;
311         u64 found_transid = btrfs_super_generation(disk_super);
312         char *name;
313
314         fs_devices = find_fsid(disk_super->fsid);
315         if (!fs_devices) {
316                 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
317                 if (!fs_devices)
318                         return -ENOMEM;
319                 INIT_LIST_HEAD(&fs_devices->devices);
320                 INIT_LIST_HEAD(&fs_devices->alloc_list);
321                 list_add(&fs_devices->list, &fs_uuids);
322                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
323                 fs_devices->latest_devid = devid;
324                 fs_devices->latest_trans = found_transid;
325                 mutex_init(&fs_devices->device_list_mutex);
326                 device = NULL;
327         } else {
328                 device = __find_device(&fs_devices->devices, devid,
329                                        disk_super->dev_item.uuid);
330         }
331         if (!device) {
332                 if (fs_devices->opened)
333                         return -EBUSY;
334
335                 device = kzalloc(sizeof(*device), GFP_NOFS);
336                 if (!device) {
337                         /* we can safely leave the fs_devices entry around */
338                         return -ENOMEM;
339                 }
340                 device->devid = devid;
341                 device->work.func = pending_bios_fn;
342                 memcpy(device->uuid, disk_super->dev_item.uuid,
343                        BTRFS_UUID_SIZE);
344                 spin_lock_init(&device->io_lock);
345                 device->name = kstrdup(path, GFP_NOFS);
346                 if (!device->name) {
347                         kfree(device);
348                         return -ENOMEM;
349                 }
350                 INIT_LIST_HEAD(&device->dev_alloc_list);
351
352                 mutex_lock(&fs_devices->device_list_mutex);
353                 list_add_rcu(&device->dev_list, &fs_devices->devices);
354                 mutex_unlock(&fs_devices->device_list_mutex);
355
356                 device->fs_devices = fs_devices;
357                 fs_devices->num_devices++;
358         } else if (!device->name || strcmp(device->name, path)) {
359                 name = kstrdup(path, GFP_NOFS);
360                 if (!name)
361                         return -ENOMEM;
362                 kfree(device->name);
363                 device->name = name;
364                 if (device->missing) {
365                         fs_devices->missing_devices--;
366                         device->missing = 0;
367                 }
368         }
369
370         if (found_transid > fs_devices->latest_trans) {
371                 fs_devices->latest_devid = devid;
372                 fs_devices->latest_trans = found_transid;
373         }
374         *fs_devices_ret = fs_devices;
375         return 0;
376 }
377
378 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
379 {
380         struct btrfs_fs_devices *fs_devices;
381         struct btrfs_device *device;
382         struct btrfs_device *orig_dev;
383
384         fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
385         if (!fs_devices)
386                 return ERR_PTR(-ENOMEM);
387
388         INIT_LIST_HEAD(&fs_devices->devices);
389         INIT_LIST_HEAD(&fs_devices->alloc_list);
390         INIT_LIST_HEAD(&fs_devices->list);
391         mutex_init(&fs_devices->device_list_mutex);
392         fs_devices->latest_devid = orig->latest_devid;
393         fs_devices->latest_trans = orig->latest_trans;
394         memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));
395
396         /* We have held the volume lock, it is safe to get the devices. */
397         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
398                 device = kzalloc(sizeof(*device), GFP_NOFS);
399                 if (!device)
400                         goto error;
401
402                 device->name = kstrdup(orig_dev->name, GFP_NOFS);
403                 if (!device->name) {
404                         kfree(device);
405                         goto error;
406                 }
407
408                 device->devid = orig_dev->devid;
409                 device->work.func = pending_bios_fn;
410                 memcpy(device->uuid, orig_dev->uuid, sizeof(device->uuid));
411                 spin_lock_init(&device->io_lock);
412                 INIT_LIST_HEAD(&device->dev_list);
413                 INIT_LIST_HEAD(&device->dev_alloc_list);
414
415                 list_add(&device->dev_list, &fs_devices->devices);
416                 device->fs_devices = fs_devices;
417                 fs_devices->num_devices++;
418         }
419         return fs_devices;
420 error:
421         free_fs_devices(fs_devices);
422         return ERR_PTR(-ENOMEM);
423 }
424
425 int btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices)
426 {
427         struct btrfs_device *device, *next;
428
429         mutex_lock(&uuid_mutex);
430 again:
431         /* This is the initialized path, it is safe to release the devices. */
432         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
433                 if (device->in_fs_metadata)
434                         continue;
435
436                 if (device->bdev) {
437                         blkdev_put(device->bdev, device->mode);
438                         device->bdev = NULL;
439                         fs_devices->open_devices--;
440                 }
441                 if (device->writeable) {
442                         list_del_init(&device->dev_alloc_list);
443                         device->writeable = 0;
444                         fs_devices->rw_devices--;
445                 }
446                 list_del_init(&device->dev_list);
447                 fs_devices->num_devices--;
448                 kfree(device->name);
449                 kfree(device);
450         }
451
452         if (fs_devices->seed) {
453                 fs_devices = fs_devices->seed;
454                 goto again;
455         }
456
457         mutex_unlock(&uuid_mutex);
458         return 0;
459 }
460
461 static void __free_device(struct work_struct *work)
462 {
463         struct btrfs_device *device;
464
465         device = container_of(work, struct btrfs_device, rcu_work);
466
467         if (device->bdev)
468                 blkdev_put(device->bdev, device->mode);
469
470         kfree(device->name);
471         kfree(device);
472 }
473
474 static void free_device(struct rcu_head *head)
475 {
476         struct btrfs_device *device;
477
478         device = container_of(head, struct btrfs_device, rcu);
479
480         INIT_WORK(&device->rcu_work, __free_device);
481         schedule_work(&device->rcu_work);
482 }
483
484 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
485 {
486         struct btrfs_device *device;
487
488         if (--fs_devices->opened > 0)
489                 return 0;
490
491         mutex_lock(&fs_devices->device_list_mutex);
492         list_for_each_entry(device, &fs_devices->devices, dev_list) {
493                 struct btrfs_device *new_device;
494
495                 if (device->bdev)
496                         fs_devices->open_devices--;
497
498                 if (device->writeable) {
499                         list_del_init(&device->dev_alloc_list);
500                         fs_devices->rw_devices--;
501                 }
502
503                 new_device = kmalloc(sizeof(*new_device), GFP_NOFS);
504                 BUG_ON(!new_device);
505                 memcpy(new_device, device, sizeof(*new_device));
506                 new_device->name = kstrdup(device->name, GFP_NOFS);
507                 BUG_ON(device->name && !new_device->name);
508                 new_device->bdev = NULL;
509                 new_device->writeable = 0;
510                 new_device->in_fs_metadata = 0;
511                 list_replace_rcu(&device->dev_list, &new_device->dev_list);
512
513                 call_rcu(&device->rcu, free_device);
514         }
515         mutex_unlock(&fs_devices->device_list_mutex);
516
517         WARN_ON(fs_devices->open_devices);
518         WARN_ON(fs_devices->rw_devices);
519         fs_devices->opened = 0;
520         fs_devices->seeding = 0;
521
522         return 0;
523 }
524
525 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
526 {
527         struct btrfs_fs_devices *seed_devices = NULL;
528         int ret;
529
530         mutex_lock(&uuid_mutex);
531         ret = __btrfs_close_devices(fs_devices);
532         if (!fs_devices->opened) {
533                 seed_devices = fs_devices->seed;
534                 fs_devices->seed = NULL;
535         }
536         mutex_unlock(&uuid_mutex);
537
538         while (seed_devices) {
539                 fs_devices = seed_devices;
540                 seed_devices = fs_devices->seed;
541                 __btrfs_close_devices(fs_devices);
542                 free_fs_devices(fs_devices);
543         }
544         return ret;
545 }
546
547 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
548                                 fmode_t flags, void *holder)
549 {
550         struct block_device *bdev;
551         struct list_head *head = &fs_devices->devices;
552         struct btrfs_device *device;
553         struct block_device *latest_bdev = NULL;
554         struct buffer_head *bh;
555         struct btrfs_super_block *disk_super;
556         u64 latest_devid = 0;
557         u64 latest_transid = 0;
558         u64 devid;
559         int seeding = 1;
560         int ret = 0;
561
562         flags |= FMODE_EXCL;
563
564         list_for_each_entry(device, head, dev_list) {
565                 if (device->bdev)
566                         continue;
567                 if (!device->name)
568                         continue;
569
570                 bdev = blkdev_get_by_path(device->name, flags, holder);
571                 if (IS_ERR(bdev)) {
572                         printk(KERN_INFO "open %s failed\n", device->name);
573                         goto error;
574                 }
575                 set_blocksize(bdev, 4096);
576
577                 bh = btrfs_read_dev_super(bdev);
578                 if (!bh) {
579                         ret = -EINVAL;
580                         goto error_close;
581                 }
582
583                 disk_super = (struct btrfs_super_block *)bh->b_data;
584                 devid = btrfs_stack_device_id(&disk_super->dev_item);
585                 if (devid != device->devid)
586                         goto error_brelse;
587
588                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
589                            BTRFS_UUID_SIZE))
590                         goto error_brelse;
591
592                 device->generation = btrfs_super_generation(disk_super);
593                 if (!latest_transid || device->generation > latest_transid) {
594                         latest_devid = devid;
595                         latest_transid = device->generation;
596                         latest_bdev = bdev;
597                 }
598
599                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
600                         device->writeable = 0;
601                 } else {
602                         device->writeable = !bdev_read_only(bdev);
603                         seeding = 0;
604                 }
605
606                 device->bdev = bdev;
607                 device->in_fs_metadata = 0;
608                 device->mode = flags;
609
610                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
611                         fs_devices->rotating = 1;
612
613                 fs_devices->open_devices++;
614                 if (device->writeable) {
615                         fs_devices->rw_devices++;
616                         list_add(&device->dev_alloc_list,
617                                  &fs_devices->alloc_list);
618                 }
619                 brelse(bh);
620                 continue;
621
622 error_brelse:
623                 brelse(bh);
624 error_close:
625                 blkdev_put(bdev, flags);
626 error:
627                 continue;
628         }
629         if (fs_devices->open_devices == 0) {
630                 ret = -EIO;
631                 goto out;
632         }
633         fs_devices->seeding = seeding;
634         fs_devices->opened = 1;
635         fs_devices->latest_bdev = latest_bdev;
636         fs_devices->latest_devid = latest_devid;
637         fs_devices->latest_trans = latest_transid;
638         fs_devices->total_rw_bytes = 0;
639 out:
640         return ret;
641 }
642
643 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
644                        fmode_t flags, void *holder)
645 {
646         int ret;
647
648         mutex_lock(&uuid_mutex);
649         if (fs_devices->opened) {
650                 fs_devices->opened++;
651                 ret = 0;
652         } else {
653                 ret = __btrfs_open_devices(fs_devices, flags, holder);
654         }
655         mutex_unlock(&uuid_mutex);
656         return ret;
657 }
658
659 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
660                           struct btrfs_fs_devices **fs_devices_ret)
661 {
662         struct btrfs_super_block *disk_super;
663         struct block_device *bdev;
664         struct buffer_head *bh;
665         int ret;
666         u64 devid;
667         u64 transid;
668
669         mutex_lock(&uuid_mutex);
670
671         flags |= FMODE_EXCL;
672         bdev = blkdev_get_by_path(path, flags, holder);
673
674         if (IS_ERR(bdev)) {
675                 ret = PTR_ERR(bdev);
676                 goto error;
677         }
678
679         ret = set_blocksize(bdev, 4096);
680         if (ret)
681                 goto error_close;
682         bh = btrfs_read_dev_super(bdev);
683         if (!bh) {
684                 ret = -EINVAL;
685                 goto error_close;
686         }
687         disk_super = (struct btrfs_super_block *)bh->b_data;
688         devid = btrfs_stack_device_id(&disk_super->dev_item);
689         transid = btrfs_super_generation(disk_super);
690         if (disk_super->label[0])
691                 printk(KERN_INFO "device label %s ", disk_super->label);
692         else
693                 printk(KERN_INFO "device fsid %pU ", disk_super->fsid);
694         printk(KERN_CONT "devid %llu transid %llu %s\n",
695                (unsigned long long)devid, (unsigned long long)transid, path);
696         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
697
698         brelse(bh);
699 error_close:
700         blkdev_put(bdev, flags);
701 error:
702         mutex_unlock(&uuid_mutex);
703         return ret;
704 }
705
706 /* helper to account the used device space in the range */
707 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
708                                    u64 end, u64 *length)
709 {
710         struct btrfs_key key;
711         struct btrfs_root *root = device->dev_root;
712         struct btrfs_dev_extent *dev_extent;
713         struct btrfs_path *path;
714         u64 extent_end;
715         int ret;
716         int slot;
717         struct extent_buffer *l;
718
719         *length = 0;
720
721         if (start >= device->total_bytes)
722                 return 0;
723
724         path = btrfs_alloc_path();
725         if (!path)
726                 return -ENOMEM;
727         path->reada = 2;
728
729         key.objectid = device->devid;
730         key.offset = start;
731         key.type = BTRFS_DEV_EXTENT_KEY;
732
733         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
734         if (ret < 0)
735                 goto out;
736         if (ret > 0) {
737                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
738                 if (ret < 0)
739                         goto out;
740         }
741
742         while (1) {
743                 l = path->nodes[0];
744                 slot = path->slots[0];
745                 if (slot >= btrfs_header_nritems(l)) {
746                         ret = btrfs_next_leaf(root, path);
747                         if (ret == 0)
748                                 continue;
749                         if (ret < 0)
750                                 goto out;
751
752                         break;
753                 }
754                 btrfs_item_key_to_cpu(l, &key, slot);
755
756                 if (key.objectid < device->devid)
757                         goto next;
758
759                 if (key.objectid > device->devid)
760                         break;
761
762                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
763                         goto next;
764
765                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
766                 extent_end = key.offset + btrfs_dev_extent_length(l,
767                                                                   dev_extent);
768                 if (key.offset <= start && extent_end > end) {
769                         *length = end - start + 1;
770                         break;
771                 } else if (key.offset <= start && extent_end > start)
772                         *length += extent_end - start;
773                 else if (key.offset > start && extent_end <= end)
774                         *length += extent_end - key.offset;
775                 else if (key.offset > start && key.offset <= end) {
776                         *length += end - key.offset + 1;
777                         break;
778                 } else if (key.offset > end)
779                         break;
780
781 next:
782                 path->slots[0]++;
783         }
784         ret = 0;
785 out:
786         btrfs_free_path(path);
787         return ret;
788 }
789
790 /*
791  * find_free_dev_extent - find free space in the specified device
792  * @trans:      transaction handler
793  * @device:     the device which we search the free space in
794  * @num_bytes:  the size of the free space that we need
795  * @start:      store the start of the free space.
796  * @len:        the size of the free space. that we find, or the size of the max
797  *              free space if we don't find suitable free space
798  *
799  * this uses a pretty simple search, the expectation is that it is
800  * called very infrequently and that a given device has a small number
801  * of extents
802  *
803  * @start is used to store the start of the free space if we find. But if we
804  * don't find suitable free space, it will be used to store the start position
805  * of the max free space.
806  *
807  * @len is used to store the size of the free space that we find.
808  * But if we don't find suitable free space, it is used to store the size of
809  * the max free space.
810  */
811 int find_free_dev_extent(struct btrfs_trans_handle *trans,
812                          struct btrfs_device *device, u64 num_bytes,
813                          u64 *start, u64 *len)
814 {
815         struct btrfs_key key;
816         struct btrfs_root *root = device->dev_root;
817         struct btrfs_dev_extent *dev_extent;
818         struct btrfs_path *path;
819         u64 hole_size;
820         u64 max_hole_start;
821         u64 max_hole_size;
822         u64 extent_end;
823         u64 search_start;
824         u64 search_end = device->total_bytes;
825         int ret;
826         int slot;
827         struct extent_buffer *l;
828
829         /* FIXME use last free of some kind */
830
831         /* we don't want to overwrite the superblock on the drive,
832          * so we make sure to start at an offset of at least 1MB
833          */
834         search_start = max(root->fs_info->alloc_start, 1024ull * 1024);
835
836         max_hole_start = search_start;
837         max_hole_size = 0;
838
839         if (search_start >= search_end) {
840                 ret = -ENOSPC;
841                 goto error;
842         }
843
844         path = btrfs_alloc_path();
845         if (!path) {
846                 ret = -ENOMEM;
847                 goto error;
848         }
849         path->reada = 2;
850
851         key.objectid = device->devid;
852         key.offset = search_start;
853         key.type = BTRFS_DEV_EXTENT_KEY;
854
855         ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
856         if (ret < 0)
857                 goto out;
858         if (ret > 0) {
859                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
860                 if (ret < 0)
861                         goto out;
862         }
863
864         while (1) {
865                 l = path->nodes[0];
866                 slot = path->slots[0];
867                 if (slot >= btrfs_header_nritems(l)) {
868                         ret = btrfs_next_leaf(root, path);
869                         if (ret == 0)
870                                 continue;
871                         if (ret < 0)
872                                 goto out;
873
874                         break;
875                 }
876                 btrfs_item_key_to_cpu(l, &key, slot);
877
878                 if (key.objectid < device->devid)
879                         goto next;
880
881                 if (key.objectid > device->devid)
882                         break;
883
884                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
885                         goto next;
886
887                 if (key.offset > search_start) {
888                         hole_size = key.offset - search_start;
889
890                         if (hole_size > max_hole_size) {
891                                 max_hole_start = search_start;
892                                 max_hole_size = hole_size;
893                         }
894
895                         /*
896                          * If this free space is greater than which we need,
897                          * it must be the max free space that we have found
898                          * until now, so max_hole_start must point to the start
899                          * of this free space and the length of this free space
900                          * is stored in max_hole_size. Thus, we return
901                          * max_hole_start and max_hole_size and go back to the
902                          * caller.
903                          */
904                         if (hole_size >= num_bytes) {
905                                 ret = 0;
906                                 goto out;
907                         }
908                 }
909
910                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
911                 extent_end = key.offset + btrfs_dev_extent_length(l,
912                                                                   dev_extent);
913                 if (extent_end > search_start)
914                         search_start = extent_end;
915 next:
916                 path->slots[0]++;
917                 cond_resched();
918         }
919
920         hole_size = search_end- search_start;
921         if (hole_size > max_hole_size) {
922                 max_hole_start = search_start;
923                 max_hole_size = hole_size;
924         }
925
926         /* See above. */
927         if (hole_size < num_bytes)
928                 ret = -ENOSPC;
929         else
930                 ret = 0;
931
932 out:
933         btrfs_free_path(path);
934 error:
935         *start = max_hole_start;
936         if (len)
937                 *len = max_hole_size;
938         return ret;
939 }
940
941 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
942                           struct btrfs_device *device,
943                           u64 start)
944 {
945         int ret;
946         struct btrfs_path *path;
947         struct btrfs_root *root = device->dev_root;
948         struct btrfs_key key;
949         struct btrfs_key found_key;
950         struct extent_buffer *leaf = NULL;
951         struct btrfs_dev_extent *extent = NULL;
952
953         path = btrfs_alloc_path();
954         if (!path)
955                 return -ENOMEM;
956
957         key.objectid = device->devid;
958         key.offset = start;
959         key.type = BTRFS_DEV_EXTENT_KEY;
960
961         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
962         if (ret > 0) {
963                 ret = btrfs_previous_item(root, path, key.objectid,
964                                           BTRFS_DEV_EXTENT_KEY);
965                 if (ret)
966                         goto out;
967                 leaf = path->nodes[0];
968                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
969                 extent = btrfs_item_ptr(leaf, path->slots[0],
970                                         struct btrfs_dev_extent);
971                 BUG_ON(found_key.offset > start || found_key.offset +
972                        btrfs_dev_extent_length(leaf, extent) < start);
973         } else if (ret == 0) {
974                 leaf = path->nodes[0];
975                 extent = btrfs_item_ptr(leaf, path->slots[0],
976                                         struct btrfs_dev_extent);
977         }
978         BUG_ON(ret);
979
980         if (device->bytes_used > 0)
981                 device->bytes_used -= btrfs_dev_extent_length(leaf, extent);
982         ret = btrfs_del_item(trans, root, path);
983
984 out:
985         btrfs_free_path(path);
986         return ret;
987 }
988
989 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
990                            struct btrfs_device *device,
991                            u64 chunk_tree, u64 chunk_objectid,
992                            u64 chunk_offset, u64 start, u64 num_bytes)
993 {
994         int ret;
995         struct btrfs_path *path;
996         struct btrfs_root *root = device->dev_root;
997         struct btrfs_dev_extent *extent;
998         struct extent_buffer *leaf;
999         struct btrfs_key key;
1000
1001         WARN_ON(!device->in_fs_metadata);
1002         path = btrfs_alloc_path();
1003         if (!path)
1004                 return -ENOMEM;
1005
1006         key.objectid = device->devid;
1007         key.offset = start;
1008         key.type = BTRFS_DEV_EXTENT_KEY;
1009         ret = btrfs_insert_empty_item(trans, root, path, &key,
1010                                       sizeof(*extent));
1011         BUG_ON(ret);
1012
1013         leaf = path->nodes[0];
1014         extent = btrfs_item_ptr(leaf, path->slots[0],
1015                                 struct btrfs_dev_extent);
1016         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
1017         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
1018         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
1019
1020         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
1021                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
1022                     BTRFS_UUID_SIZE);
1023
1024         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
1025         btrfs_mark_buffer_dirty(leaf);
1026         btrfs_free_path(path);
1027         return ret;
1028 }
1029
1030 static noinline int find_next_chunk(struct btrfs_root *root,
1031                                     u64 objectid, u64 *offset)
1032 {
1033         struct btrfs_path *path;
1034         int ret;
1035         struct btrfs_key key;
1036         struct btrfs_chunk *chunk;
1037         struct btrfs_key found_key;
1038
1039         path = btrfs_alloc_path();
1040         BUG_ON(!path);
1041
1042         key.objectid = objectid;
1043         key.offset = (u64)-1;
1044         key.type = BTRFS_CHUNK_ITEM_KEY;
1045
1046         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1047         if (ret < 0)
1048                 goto error;
1049
1050         BUG_ON(ret == 0);
1051
1052         ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
1053         if (ret) {
1054                 *offset = 0;
1055         } else {
1056                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1057                                       path->slots[0]);
1058                 if (found_key.objectid != objectid)
1059                         *offset = 0;
1060                 else {
1061                         chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
1062                                                struct btrfs_chunk);
1063                         *offset = found_key.offset +
1064                                 btrfs_chunk_length(path->nodes[0], chunk);
1065                 }
1066         }
1067         ret = 0;
1068 error:
1069         btrfs_free_path(path);
1070         return ret;
1071 }
1072
1073 static noinline int find_next_devid(struct btrfs_root *root, u64 *objectid)
1074 {
1075         int ret;
1076         struct btrfs_key key;
1077         struct btrfs_key found_key;
1078         struct btrfs_path *path;
1079
1080         root = root->fs_info->chunk_root;
1081
1082         path = btrfs_alloc_path();
1083         if (!path)
1084                 return -ENOMEM;
1085
1086         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1087         key.type = BTRFS_DEV_ITEM_KEY;
1088         key.offset = (u64)-1;
1089
1090         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1091         if (ret < 0)
1092                 goto error;
1093
1094         BUG_ON(ret == 0);
1095
1096         ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
1097                                   BTRFS_DEV_ITEM_KEY);
1098         if (ret) {
1099                 *objectid = 1;
1100         } else {
1101                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1102                                       path->slots[0]);
1103                 *objectid = found_key.offset + 1;
1104         }
1105         ret = 0;
1106 error:
1107         btrfs_free_path(path);
1108         return ret;
1109 }
1110
1111 /*
1112  * the device information is stored in the chunk root
1113  * the btrfs_device struct should be fully filled in
1114  */
1115 int btrfs_add_device(struct btrfs_trans_handle *trans,
1116                      struct btrfs_root *root,
1117                      struct btrfs_device *device)
1118 {
1119         int ret;
1120         struct btrfs_path *path;
1121         struct btrfs_dev_item *dev_item;
1122         struct extent_buffer *leaf;
1123         struct btrfs_key key;
1124         unsigned long ptr;
1125
1126         root = root->fs_info->chunk_root;
1127
1128         path = btrfs_alloc_path();
1129         if (!path)
1130                 return -ENOMEM;
1131
1132         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1133         key.type = BTRFS_DEV_ITEM_KEY;
1134         key.offset = device->devid;
1135
1136         ret = btrfs_insert_empty_item(trans, root, path, &key,
1137                                       sizeof(*dev_item));
1138         if (ret)
1139                 goto out;
1140
1141         leaf = path->nodes[0];
1142         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1143
1144         btrfs_set_device_id(leaf, dev_item, device->devid);
1145         btrfs_set_device_generation(leaf, dev_item, 0);
1146         btrfs_set_device_type(leaf, dev_item, device->type);
1147         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1148         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1149         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1150         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
1151         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1152         btrfs_set_device_group(leaf, dev_item, 0);
1153         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1154         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1155         btrfs_set_device_start_offset(leaf, dev_item, 0);
1156
1157         ptr = (unsigned long)btrfs_device_uuid(dev_item);
1158         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1159         ptr = (unsigned long)btrfs_device_fsid(dev_item);
1160         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1161         btrfs_mark_buffer_dirty(leaf);
1162
1163         ret = 0;
1164 out:
1165         btrfs_free_path(path);
1166         return ret;
1167 }
1168
1169 static int btrfs_rm_dev_item(struct btrfs_root *root,
1170                              struct btrfs_device *device)
1171 {
1172         int ret;
1173         struct btrfs_path *path;
1174         struct btrfs_key key;
1175         struct btrfs_trans_handle *trans;
1176
1177         root = root->fs_info->chunk_root;
1178
1179         path = btrfs_alloc_path();
1180         if (!path)
1181                 return -ENOMEM;
1182
1183         trans = btrfs_start_transaction(root, 0);
1184         if (IS_ERR(trans)) {
1185                 btrfs_free_path(path);
1186                 return PTR_ERR(trans);
1187         }
1188         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1189         key.type = BTRFS_DEV_ITEM_KEY;
1190         key.offset = device->devid;
1191         lock_chunks(root);
1192
1193         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1194         if (ret < 0)
1195                 goto out;
1196
1197         if (ret > 0) {
1198                 ret = -ENOENT;
1199                 goto out;
1200         }
1201
1202         ret = btrfs_del_item(trans, root, path);
1203         if (ret)
1204                 goto out;
1205 out:
1206         btrfs_free_path(path);
1207         unlock_chunks(root);
1208         btrfs_commit_transaction(trans, root);
1209         return ret;
1210 }
1211
1212 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1213 {
1214         struct btrfs_device *device;
1215         struct btrfs_device *next_device;
1216         struct block_device *bdev;
1217         struct buffer_head *bh = NULL;
1218         struct btrfs_super_block *disk_super;
1219         struct btrfs_fs_devices *cur_devices;
1220         u64 all_avail;
1221         u64 devid;
1222         u64 num_devices;
1223         u8 *dev_uuid;
1224         int ret = 0;
1225         bool clear_super = false;
1226
1227         mutex_lock(&uuid_mutex);
1228         mutex_lock(&root->fs_info->volume_mutex);
1229
1230         all_avail = root->fs_info->avail_data_alloc_bits |
1231                 root->fs_info->avail_system_alloc_bits |
1232                 root->fs_info->avail_metadata_alloc_bits;
1233
1234         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) &&
1235             root->fs_info->fs_devices->num_devices <= 4) {
1236                 printk(KERN_ERR "btrfs: unable to go below four devices "
1237                        "on raid10\n");
1238                 ret = -EINVAL;
1239                 goto out;
1240         }
1241
1242         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) &&
1243             root->fs_info->fs_devices->num_devices <= 2) {
1244                 printk(KERN_ERR "btrfs: unable to go below two "
1245                        "devices on raid1\n");
1246                 ret = -EINVAL;
1247                 goto out;
1248         }
1249
1250         if (strcmp(device_path, "missing") == 0) {
1251                 struct list_head *devices;
1252                 struct btrfs_device *tmp;
1253
1254                 device = NULL;
1255                 devices = &root->fs_info->fs_devices->devices;
1256                 /*
1257                  * It is safe to read the devices since the volume_mutex
1258                  * is held.
1259                  */
1260                 list_for_each_entry(tmp, devices, dev_list) {
1261                         if (tmp->in_fs_metadata && !tmp->bdev) {
1262                                 device = tmp;
1263                                 break;
1264                         }
1265                 }
1266                 bdev = NULL;
1267                 bh = NULL;
1268                 disk_super = NULL;
1269                 if (!device) {
1270                         printk(KERN_ERR "btrfs: no missing devices found to "
1271                                "remove\n");
1272                         goto out;
1273                 }
1274         } else {
1275                 bdev = blkdev_get_by_path(device_path, FMODE_READ | FMODE_EXCL,
1276                                           root->fs_info->bdev_holder);
1277                 if (IS_ERR(bdev)) {
1278                         ret = PTR_ERR(bdev);
1279                         goto out;
1280                 }
1281
1282                 set_blocksize(bdev, 4096);
1283                 bh = btrfs_read_dev_super(bdev);
1284                 if (!bh) {
1285                         ret = -EINVAL;
1286                         goto error_close;
1287                 }
1288                 disk_super = (struct btrfs_super_block *)bh->b_data;
1289                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1290                 dev_uuid = disk_super->dev_item.uuid;
1291                 device = btrfs_find_device(root, devid, dev_uuid,
1292                                            disk_super->fsid);
1293                 if (!device) {
1294                         ret = -ENOENT;
1295                         goto error_brelse;
1296                 }
1297         }
1298
1299         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1300                 printk(KERN_ERR "btrfs: unable to remove the only writeable "
1301                        "device\n");
1302                 ret = -EINVAL;
1303                 goto error_brelse;
1304         }
1305
1306         if (device->writeable) {
1307                 lock_chunks(root);
1308                 list_del_init(&device->dev_alloc_list);
1309                 unlock_chunks(root);
1310                 root->fs_info->fs_devices->rw_devices--;
1311                 clear_super = true;
1312         }
1313
1314         ret = btrfs_shrink_device(device, 0);
1315         if (ret)
1316                 goto error_undo;
1317
1318         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1319         if (ret)
1320                 goto error_undo;
1321
1322         device->in_fs_metadata = 0;
1323         btrfs_scrub_cancel_dev(root, device);
1324
1325         /*
1326          * the device list mutex makes sure that we don't change
1327          * the device list while someone else is writing out all
1328          * the device supers.
1329          */
1330
1331         cur_devices = device->fs_devices;
1332         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1333         list_del_rcu(&device->dev_list);
1334
1335         device->fs_devices->num_devices--;
1336
1337         if (device->missing)
1338                 root->fs_info->fs_devices->missing_devices--;
1339
1340         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1341                                  struct btrfs_device, dev_list);
1342         if (device->bdev == root->fs_info->sb->s_bdev)
1343                 root->fs_info->sb->s_bdev = next_device->bdev;
1344         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1345                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1346
1347         if (device->bdev)
1348                 device->fs_devices->open_devices--;
1349
1350         call_rcu(&device->rcu, free_device);
1351         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1352
1353         num_devices = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
1354         btrfs_set_super_num_devices(&root->fs_info->super_copy, num_devices);
1355
1356         if (cur_devices->open_devices == 0) {
1357                 struct btrfs_fs_devices *fs_devices;
1358                 fs_devices = root->fs_info->fs_devices;
1359                 while (fs_devices) {
1360                         if (fs_devices->seed == cur_devices)
1361                                 break;
1362                         fs_devices = fs_devices->seed;
1363                 }
1364                 fs_devices->seed = cur_devices->seed;
1365                 cur_devices->seed = NULL;
1366                 lock_chunks(root);
1367                 __btrfs_close_devices(cur_devices);
1368                 unlock_chunks(root);
1369                 free_fs_devices(cur_devices);
1370         }
1371
1372         /*
1373          * at this point, the device is zero sized.  We want to
1374          * remove it from the devices list and zero out the old super
1375          */
1376         if (clear_super) {
1377                 /* make sure this device isn't detected as part of
1378                  * the FS anymore
1379                  */
1380                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1381                 set_buffer_dirty(bh);
1382                 sync_dirty_buffer(bh);
1383         }
1384
1385         ret = 0;
1386
1387 error_brelse:
1388         brelse(bh);
1389 error_close:
1390         if (bdev)
1391                 blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
1392 out:
1393         mutex_unlock(&root->fs_info->volume_mutex);
1394         mutex_unlock(&uuid_mutex);
1395         return ret;
1396 error_undo:
1397         if (device->writeable) {
1398                 lock_chunks(root);
1399                 list_add(&device->dev_alloc_list,
1400                          &root->fs_info->fs_devices->alloc_list);
1401                 unlock_chunks(root);
1402                 root->fs_info->fs_devices->rw_devices++;
1403         }
1404         goto error_brelse;
1405 }
1406
1407 /*
1408  * does all the dirty work required for changing file system's UUID.
1409  */
1410 static int btrfs_prepare_sprout(struct btrfs_trans_handle *trans,
1411                                 struct btrfs_root *root)
1412 {
1413         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
1414         struct btrfs_fs_devices *old_devices;
1415         struct btrfs_fs_devices *seed_devices;
1416         struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
1417         struct btrfs_device *device;
1418         u64 super_flags;
1419
1420         BUG_ON(!mutex_is_locked(&uuid_mutex));
1421         if (!fs_devices->seeding)
1422                 return -EINVAL;
1423
1424         seed_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
1425         if (!seed_devices)
1426                 return -ENOMEM;
1427
1428         old_devices = clone_fs_devices(fs_devices);
1429         if (IS_ERR(old_devices)) {
1430                 kfree(seed_devices);
1431                 return PTR_ERR(old_devices);
1432         }
1433
1434         list_add(&old_devices->list, &fs_uuids);
1435
1436         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
1437         seed_devices->opened = 1;
1438         INIT_LIST_HEAD(&seed_devices->devices);
1439         INIT_LIST_HEAD(&seed_devices->alloc_list);
1440         mutex_init(&seed_devices->device_list_mutex);
1441
1442         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1443         list_splice_init_rcu(&fs_devices->devices, &seed_devices->devices,
1444                               synchronize_rcu);
1445         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1446
1447         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
1448         list_for_each_entry(device, &seed_devices->devices, dev_list) {
1449                 device->fs_devices = seed_devices;
1450         }
1451
1452         fs_devices->seeding = 0;
1453         fs_devices->num_devices = 0;
1454         fs_devices->open_devices = 0;
1455         fs_devices->seed = seed_devices;
1456
1457         generate_random_uuid(fs_devices->fsid);
1458         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1459         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1460         super_flags = btrfs_super_flags(disk_super) &
1461                       ~BTRFS_SUPER_FLAG_SEEDING;
1462         btrfs_set_super_flags(disk_super, super_flags);
1463
1464         return 0;
1465 }
1466
1467 /*
1468  * strore the expected generation for seed devices in device items.
1469  */
1470 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
1471                                struct btrfs_root *root)
1472 {
1473         struct btrfs_path *path;
1474         struct extent_buffer *leaf;
1475         struct btrfs_dev_item *dev_item;
1476         struct btrfs_device *device;
1477         struct btrfs_key key;
1478         u8 fs_uuid[BTRFS_UUID_SIZE];
1479         u8 dev_uuid[BTRFS_UUID_SIZE];
1480         u64 devid;
1481         int ret;
1482
1483         path = btrfs_alloc_path();
1484         if (!path)
1485                 return -ENOMEM;
1486
1487         root = root->fs_info->chunk_root;
1488         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1489         key.offset = 0;
1490         key.type = BTRFS_DEV_ITEM_KEY;
1491
1492         while (1) {
1493                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1494                 if (ret < 0)
1495                         goto error;
1496
1497                 leaf = path->nodes[0];
1498 next_slot:
1499                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1500                         ret = btrfs_next_leaf(root, path);
1501                         if (ret > 0)
1502                                 break;
1503                         if (ret < 0)
1504                                 goto error;
1505                         leaf = path->nodes[0];
1506                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1507                         btrfs_release_path(path);
1508                         continue;
1509                 }
1510
1511                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1512                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
1513                     key.type != BTRFS_DEV_ITEM_KEY)
1514                         break;
1515
1516                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
1517                                           struct btrfs_dev_item);
1518                 devid = btrfs_device_id(leaf, dev_item);
1519                 read_extent_buffer(leaf, dev_uuid,
1520                                    (unsigned long)btrfs_device_uuid(dev_item),
1521                                    BTRFS_UUID_SIZE);
1522                 read_extent_buffer(leaf, fs_uuid,
1523                                    (unsigned long)btrfs_device_fsid(dev_item),
1524                                    BTRFS_UUID_SIZE);
1525                 device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
1526                 BUG_ON(!device);
1527
1528                 if (device->fs_devices->seeding) {
1529                         btrfs_set_device_generation(leaf, dev_item,
1530                                                     device->generation);
1531                         btrfs_mark_buffer_dirty(leaf);
1532                 }
1533
1534                 path->slots[0]++;
1535                 goto next_slot;
1536         }
1537         ret = 0;
1538 error:
1539         btrfs_free_path(path);
1540         return ret;
1541 }
1542
1543 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
1544 {
1545         struct btrfs_trans_handle *trans;
1546         struct btrfs_device *device;
1547         struct block_device *bdev;
1548         struct list_head *devices;
1549         struct super_block *sb = root->fs_info->sb;
1550         u64 total_bytes;
1551         int seeding_dev = 0;
1552         int ret = 0;
1553
1554         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
1555                 return -EINVAL;
1556
1557         bdev = blkdev_get_by_path(device_path, FMODE_EXCL,
1558                                   root->fs_info->bdev_holder);
1559         if (IS_ERR(bdev))
1560                 return PTR_ERR(bdev);
1561
1562         if (root->fs_info->fs_devices->seeding) {
1563                 seeding_dev = 1;
1564                 down_write(&sb->s_umount);
1565                 mutex_lock(&uuid_mutex);
1566         }
1567
1568         filemap_write_and_wait(bdev->bd_inode->i_mapping);
1569         mutex_lock(&root->fs_info->volume_mutex);
1570
1571         devices = &root->fs_info->fs_devices->devices;
1572         /*
1573          * we have the volume lock, so we don't need the extra
1574          * device list mutex while reading the list here.
1575          */
1576         list_for_each_entry(device, devices, dev_list) {
1577                 if (device->bdev == bdev) {
1578                         ret = -EEXIST;
1579                         goto error;
1580                 }
1581         }
1582
1583         device = kzalloc(sizeof(*device), GFP_NOFS);
1584         if (!device) {
1585                 /* we can safely leave the fs_devices entry around */
1586                 ret = -ENOMEM;
1587                 goto error;
1588         }
1589
1590         device->name = kstrdup(device_path, GFP_NOFS);
1591         if (!device->name) {
1592                 kfree(device);
1593                 ret = -ENOMEM;
1594                 goto error;
1595         }
1596
1597         ret = find_next_devid(root, &device->devid);
1598         if (ret) {
1599                 kfree(device->name);
1600                 kfree(device);
1601                 goto error;
1602         }
1603
1604         trans = btrfs_start_transaction(root, 0);
1605         if (IS_ERR(trans)) {
1606                 kfree(device->name);
1607                 kfree(device);
1608                 ret = PTR_ERR(trans);
1609                 goto error;
1610         }
1611
1612         lock_chunks(root);
1613
1614         device->writeable = 1;
1615         device->work.func = pending_bios_fn;
1616         generate_random_uuid(device->uuid);
1617         spin_lock_init(&device->io_lock);
1618         device->generation = trans->transid;
1619         device->io_width = root->sectorsize;
1620         device->io_align = root->sectorsize;
1621         device->sector_size = root->sectorsize;
1622         device->total_bytes = i_size_read(bdev->bd_inode);
1623         device->disk_total_bytes = device->total_bytes;
1624         device->dev_root = root->fs_info->dev_root;
1625         device->bdev = bdev;
1626         device->in_fs_metadata = 1;
1627         device->mode = FMODE_EXCL;
1628         set_blocksize(device->bdev, 4096);
1629
1630         if (seeding_dev) {
1631                 sb->s_flags &= ~MS_RDONLY;
1632                 ret = btrfs_prepare_sprout(trans, root);
1633                 BUG_ON(ret);
1634         }
1635
1636         device->fs_devices = root->fs_info->fs_devices;
1637
1638         /*
1639          * we don't want write_supers to jump in here with our device
1640          * half setup
1641          */
1642         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1643         list_add_rcu(&device->dev_list, &root->fs_info->fs_devices->devices);
1644         list_add(&device->dev_alloc_list,
1645                  &root->fs_info->fs_devices->alloc_list);
1646         root->fs_info->fs_devices->num_devices++;
1647         root->fs_info->fs_devices->open_devices++;
1648         root->fs_info->fs_devices->rw_devices++;
1649         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
1650
1651         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
1652                 root->fs_info->fs_devices->rotating = 1;
1653
1654         total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
1655         btrfs_set_super_total_bytes(&root->fs_info->super_copy,
1656                                     total_bytes + device->total_bytes);
1657
1658         total_bytes = btrfs_super_num_devices(&root->fs_info->super_copy);
1659         btrfs_set_super_num_devices(&root->fs_info->super_copy,
1660                                     total_bytes + 1);
1661         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1662
1663         if (seeding_dev) {
1664                 ret = init_first_rw_device(trans, root, device);
1665                 BUG_ON(ret);
1666                 ret = btrfs_finish_sprout(trans, root);
1667                 BUG_ON(ret);
1668         } else {
1669                 ret = btrfs_add_device(trans, root, device);
1670         }
1671
1672         /*
1673          * we've got more storage, clear any full flags on the space
1674          * infos
1675          */
1676         btrfs_clear_space_info_full(root->fs_info);
1677
1678         unlock_chunks(root);
1679         btrfs_commit_transaction(trans, root);
1680
1681         if (seeding_dev) {
1682                 mutex_unlock(&uuid_mutex);
1683                 up_write(&sb->s_umount);
1684
1685                 ret = btrfs_relocate_sys_chunks(root);
1686                 BUG_ON(ret);
1687         }
1688 out:
1689         mutex_unlock(&root->fs_info->volume_mutex);
1690         return ret;
1691 error:
1692         blkdev_put(bdev, FMODE_EXCL);
1693         if (seeding_dev) {
1694                 mutex_unlock(&uuid_mutex);
1695                 up_write(&sb->s_umount);
1696         }
1697         goto out;
1698 }
1699
1700 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
1701                                         struct btrfs_device *device)
1702 {
1703         int ret;
1704         struct btrfs_path *path;
1705         struct btrfs_root *root;
1706         struct btrfs_dev_item *dev_item;
1707         struct extent_buffer *leaf;
1708         struct btrfs_key key;
1709
1710         root = device->dev_root->fs_info->chunk_root;
1711
1712         path = btrfs_alloc_path();
1713         if (!path)
1714                 return -ENOMEM;
1715
1716         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1717         key.type = BTRFS_DEV_ITEM_KEY;
1718         key.offset = device->devid;
1719
1720         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1721         if (ret < 0)
1722                 goto out;
1723
1724         if (ret > 0) {
1725                 ret = -ENOENT;
1726                 goto out;
1727         }
1728
1729         leaf = path->nodes[0];
1730         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1731
1732         btrfs_set_device_id(leaf, dev_item, device->devid);
1733         btrfs_set_device_type(leaf, dev_item, device->type);
1734         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1735         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1736         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1737         btrfs_set_device_total_bytes(leaf, dev_item, device->disk_total_bytes);
1738         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1739         btrfs_mark_buffer_dirty(leaf);
1740
1741 out:
1742         btrfs_free_path(path);
1743         return ret;
1744 }
1745
1746 static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
1747                       struct btrfs_device *device, u64 new_size)
1748 {
1749         struct btrfs_super_block *super_copy =
1750                 &device->dev_root->fs_info->super_copy;
1751         u64 old_total = btrfs_super_total_bytes(super_copy);
1752         u64 diff = new_size - device->total_bytes;
1753
1754         if (!device->writeable)
1755                 return -EACCES;
1756         if (new_size <= device->total_bytes)
1757                 return -EINVAL;
1758
1759         btrfs_set_super_total_bytes(super_copy, old_total + diff);
1760         device->fs_devices->total_rw_bytes += diff;
1761
1762         device->total_bytes = new_size;
1763         device->disk_total_bytes = new_size;
1764         btrfs_clear_space_info_full(device->dev_root->fs_info);
1765
1766         return btrfs_update_device(trans, device);
1767 }
1768
1769 int btrfs_grow_device(struct btrfs_trans_handle *trans,
1770                       struct btrfs_device *device, u64 new_size)
1771 {
1772         int ret;
1773         lock_chunks(device->dev_root);
1774         ret = __btrfs_grow_device(trans, device, new_size);
1775         unlock_chunks(device->dev_root);
1776         return ret;
1777 }
1778
1779 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
1780                             struct btrfs_root *root,
1781                             u64 chunk_tree, u64 chunk_objectid,
1782                             u64 chunk_offset)
1783 {
1784         int ret;
1785         struct btrfs_path *path;
1786         struct btrfs_key key;
1787
1788         root = root->fs_info->chunk_root;
1789         path = btrfs_alloc_path();
1790         if (!path)
1791                 return -ENOMEM;
1792
1793         key.objectid = chunk_objectid;
1794         key.offset = chunk_offset;
1795         key.type = BTRFS_CHUNK_ITEM_KEY;
1796
1797         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1798         BUG_ON(ret);
1799
1800         ret = btrfs_del_item(trans, root, path);
1801
1802         btrfs_free_path(path);
1803         return ret;
1804 }
1805
1806 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
1807                         chunk_offset)
1808 {
1809         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
1810         struct btrfs_disk_key *disk_key;
1811         struct btrfs_chunk *chunk;
1812         u8 *ptr;
1813         int ret = 0;
1814         u32 num_stripes;
1815         u32 array_size;
1816         u32 len = 0;
1817         u32 cur;
1818         struct btrfs_key key;
1819
1820         array_size = btrfs_super_sys_array_size(super_copy);
1821
1822         ptr = super_copy->sys_chunk_array;
1823         cur = 0;
1824
1825         while (cur < array_size) {
1826                 disk_key = (struct btrfs_disk_key *)ptr;
1827                 btrfs_disk_key_to_cpu(&key, disk_key);
1828
1829                 len = sizeof(*disk_key);
1830
1831                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
1832                         chunk = (struct btrfs_chunk *)(ptr + len);
1833                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
1834                         len += btrfs_chunk_item_size(num_stripes);
1835                 } else {
1836                         ret = -EIO;
1837                         break;
1838                 }
1839                 if (key.objectid == chunk_objectid &&
1840                     key.offset == chunk_offset) {
1841                         memmove(ptr, ptr + len, array_size - (cur + len));
1842                         array_size -= len;
1843                         btrfs_set_super_sys_array_size(super_copy, array_size);
1844                 } else {
1845                         ptr += len;
1846                         cur += len;
1847                 }
1848         }
1849         return ret;
1850 }
1851
1852 static int btrfs_relocate_chunk(struct btrfs_root *root,
1853                          u64 chunk_tree, u64 chunk_objectid,
1854                          u64 chunk_offset)
1855 {
1856         struct extent_map_tree *em_tree;
1857         struct btrfs_root *extent_root;
1858         struct btrfs_trans_handle *trans;
1859         struct extent_map *em;
1860         struct map_lookup *map;
1861         int ret;
1862         int i;
1863
1864         root = root->fs_info->chunk_root;
1865         extent_root = root->fs_info->extent_root;
1866         em_tree = &root->fs_info->mapping_tree.map_tree;
1867
1868         ret = btrfs_can_relocate(extent_root, chunk_offset);
1869         if (ret)
1870                 return -ENOSPC;
1871
1872         /* step one, relocate all the extents inside this chunk */
1873         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
1874         if (ret)
1875                 return ret;
1876
1877         trans = btrfs_start_transaction(root, 0);
1878         BUG_ON(IS_ERR(trans));
1879
1880         lock_chunks(root);
1881
1882         /*
1883          * step two, delete the device extents and the
1884          * chunk tree entries
1885          */
1886         read_lock(&em_tree->lock);
1887         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
1888         read_unlock(&em_tree->lock);
1889
1890         BUG_ON(em->start > chunk_offset ||
1891                em->start + em->len < chunk_offset);
1892         map = (struct map_lookup *)em->bdev;
1893
1894         for (i = 0; i < map->num_stripes; i++) {
1895                 ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
1896                                             map->stripes[i].physical);
1897                 BUG_ON(ret);
1898
1899                 if (map->stripes[i].dev) {
1900                         ret = btrfs_update_device(trans, map->stripes[i].dev);
1901                         BUG_ON(ret);
1902                 }
1903         }
1904         ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
1905                                chunk_offset);
1906
1907         BUG_ON(ret);
1908
1909         trace_btrfs_chunk_free(root, map, chunk_offset, em->len);
1910
1911         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
1912                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
1913                 BUG_ON(ret);
1914         }
1915
1916         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
1917         BUG_ON(ret);
1918
1919         write_lock(&em_tree->lock);
1920         remove_extent_mapping(em_tree, em);
1921         write_unlock(&em_tree->lock);
1922
1923         kfree(map);
1924         em->bdev = NULL;
1925
1926         /* once for the tree */
1927         free_extent_map(em);
1928         /* once for us */
1929         free_extent_map(em);
1930
1931         unlock_chunks(root);
1932         btrfs_end_transaction(trans, root);
1933         return 0;
1934 }
1935
1936 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
1937 {
1938         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
1939         struct btrfs_path *path;
1940         struct extent_buffer *leaf;
1941         struct btrfs_chunk *chunk;
1942         struct btrfs_key key;
1943         struct btrfs_key found_key;
1944         u64 chunk_tree = chunk_root->root_key.objectid;
1945         u64 chunk_type;
1946         bool retried = false;
1947         int failed = 0;
1948         int ret;
1949
1950         path = btrfs_alloc_path();
1951         if (!path)
1952                 return -ENOMEM;
1953
1954 again:
1955         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
1956         key.offset = (u64)-1;
1957         key.type = BTRFS_CHUNK_ITEM_KEY;
1958
1959         while (1) {
1960                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
1961                 if (ret < 0)
1962                         goto error;
1963                 BUG_ON(ret == 0);
1964
1965                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
1966                                           key.type);
1967                 if (ret < 0)
1968                         goto error;
1969                 if (ret > 0)
1970                         break;
1971
1972                 leaf = path->nodes[0];
1973                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1974
1975                 chunk = btrfs_item_ptr(leaf, path->slots[0],
1976                                        struct btrfs_chunk);
1977                 chunk_type = btrfs_chunk_type(leaf, chunk);
1978                 btrfs_release_path(path);
1979
1980                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
1981                         ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
1982                                                    found_key.objectid,
1983                                                    found_key.offset);
1984                         if (ret == -ENOSPC)
1985                                 failed++;
1986                         else if (ret)
1987                                 BUG();
1988                 }
1989
1990                 if (found_key.offset == 0)
1991                         break;
1992                 key.offset = found_key.offset - 1;
1993         }
1994         ret = 0;
1995         if (failed && !retried) {
1996                 failed = 0;
1997                 retried = true;
1998                 goto again;
1999         } else if (failed && retried) {
2000                 WARN_ON(1);
2001                 ret = -ENOSPC;
2002         }
2003 error:
2004         btrfs_free_path(path);
2005         return ret;
2006 }
2007
2008 static u64 div_factor(u64 num, int factor)
2009 {
2010         if (factor == 10)
2011                 return num;
2012         num *= factor;
2013         do_div(num, 10);
2014         return num;
2015 }
2016
2017 int btrfs_balance(struct btrfs_root *dev_root)
2018 {
2019         int ret;
2020         struct list_head *devices = &dev_root->fs_info->fs_devices->devices;
2021         struct btrfs_device *device;
2022         u64 old_size;
2023         u64 size_to_free;
2024         struct btrfs_path *path;
2025         struct btrfs_key key;
2026         struct btrfs_root *chunk_root = dev_root->fs_info->chunk_root;
2027         struct btrfs_trans_handle *trans;
2028         struct btrfs_key found_key;
2029
2030         if (dev_root->fs_info->sb->s_flags & MS_RDONLY)
2031                 return -EROFS;
2032
2033         if (!capable(CAP_SYS_ADMIN))
2034                 return -EPERM;
2035
2036         mutex_lock(&dev_root->fs_info->volume_mutex);
2037         dev_root = dev_root->fs_info->dev_root;
2038
2039         /* step one make some room on all the devices */
2040         list_for_each_entry(device, devices, dev_list) {
2041                 old_size = device->total_bytes;
2042                 size_to_free = div_factor(old_size, 1);
2043                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
2044                 if (!device->writeable ||
2045                     device->total_bytes - device->bytes_used > size_to_free)
2046                         continue;
2047
2048                 ret = btrfs_shrink_device(device, old_size - size_to_free);
2049                 if (ret == -ENOSPC)
2050                         break;
2051                 BUG_ON(ret);
2052
2053                 trans = btrfs_start_transaction(dev_root, 0);
2054                 BUG_ON(IS_ERR(trans));
2055
2056                 ret = btrfs_grow_device(trans, device, old_size);
2057                 BUG_ON(ret);
2058
2059                 btrfs_end_transaction(trans, dev_root);
2060         }
2061
2062         /* step two, relocate all the chunks */
2063         path = btrfs_alloc_path();
2064         BUG_ON(!path);
2065
2066         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2067         key.offset = (u64)-1;
2068         key.type = BTRFS_CHUNK_ITEM_KEY;
2069
2070         while (1) {
2071                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2072                 if (ret < 0)
2073                         goto error;
2074
2075                 /*
2076                  * this shouldn't happen, it means the last relocate
2077                  * failed
2078                  */
2079                 if (ret == 0)
2080                         break;
2081
2082                 ret = btrfs_previous_item(chunk_root, path, 0,
2083                                           BTRFS_CHUNK_ITEM_KEY);
2084                 if (ret)
2085                         break;
2086
2087                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
2088                                       path->slots[0]);
2089                 if (found_key.objectid != key.objectid)
2090                         break;
2091
2092                 /* chunk zero is special */
2093                 if (found_key.offset == 0)
2094                         break;
2095
2096                 btrfs_release_path(path);
2097                 ret = btrfs_relocate_chunk(chunk_root,
2098                                            chunk_root->root_key.objectid,
2099                                            found_key.objectid,
2100                                            found_key.offset);
2101                 if (ret && ret != -ENOSPC)
2102                         goto error;
2103                 key.offset = found_key.offset - 1;
2104         }
2105         ret = 0;
2106 error:
2107         btrfs_free_path(path);
2108         mutex_unlock(&dev_root->fs_info->volume_mutex);
2109         return ret;
2110 }
2111
2112 /*
2113  * shrinking a device means finding all of the device extents past
2114  * the new size, and then following the back refs to the chunks.
2115  * The chunk relocation code actually frees the device extent
2116  */
2117 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
2118 {
2119         struct btrfs_trans_handle *trans;
2120         struct btrfs_root *root = device->dev_root;
2121         struct btrfs_dev_extent *dev_extent = NULL;
2122         struct btrfs_path *path;
2123         u64 length;
2124         u64 chunk_tree;
2125         u64 chunk_objectid;
2126         u64 chunk_offset;
2127         int ret;
2128         int slot;
2129         int failed = 0;
2130         bool retried = false;
2131         struct extent_buffer *l;
2132         struct btrfs_key key;
2133         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
2134         u64 old_total = btrfs_super_total_bytes(super_copy);
2135         u64 old_size = device->total_bytes;
2136         u64 diff = device->total_bytes - new_size;
2137
2138         if (new_size >= device->total_bytes)
2139                 return -EINVAL;
2140
2141         path = btrfs_alloc_path();
2142         if (!path)
2143                 return -ENOMEM;
2144
2145         path->reada = 2;
2146
2147         lock_chunks(root);
2148
2149         device->total_bytes = new_size;
2150         if (device->writeable)
2151                 device->fs_devices->total_rw_bytes -= diff;
2152         unlock_chunks(root);
2153
2154 again:
2155         key.objectid = device->devid;
2156         key.offset = (u64)-1;
2157         key.type = BTRFS_DEV_EXTENT_KEY;
2158
2159         while (1) {
2160                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2161                 if (ret < 0)
2162                         goto done;
2163
2164                 ret = btrfs_previous_item(root, path, 0, key.type);
2165                 if (ret < 0)
2166                         goto done;
2167                 if (ret) {
2168                         ret = 0;
2169                         btrfs_release_path(path);
2170                         break;
2171                 }
2172
2173                 l = path->nodes[0];
2174                 slot = path->slots[0];
2175                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
2176
2177                 if (key.objectid != device->devid) {
2178                         btrfs_release_path(path);
2179                         break;
2180                 }
2181
2182                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
2183                 length = btrfs_dev_extent_length(l, dev_extent);
2184
2185                 if (key.offset + length <= new_size) {
2186                         btrfs_release_path(path);
2187                         break;
2188                 }
2189
2190                 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
2191                 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
2192                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
2193                 btrfs_release_path(path);
2194
2195                 ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
2196                                            chunk_offset);
2197                 if (ret && ret != -ENOSPC)
2198                         goto done;
2199                 if (ret == -ENOSPC)
2200                         failed++;
2201                 key.offset -= 1;
2202         }
2203
2204         if (failed && !retried) {
2205                 failed = 0;
2206                 retried = true;
2207                 goto again;
2208         } else if (failed && retried) {
2209                 ret = -ENOSPC;
2210                 lock_chunks(root);
2211
2212                 device->total_bytes = old_size;
2213                 if (device->writeable)
2214                         device->fs_devices->total_rw_bytes += diff;
2215                 unlock_chunks(root);
2216                 goto done;
2217         }
2218
2219         /* Shrinking succeeded, else we would be at "done". */
2220         trans = btrfs_start_transaction(root, 0);
2221         if (IS_ERR(trans)) {
2222                 ret = PTR_ERR(trans);
2223                 goto done;
2224         }
2225
2226         lock_chunks(root);
2227
2228         device->disk_total_bytes = new_size;
2229         /* Now btrfs_update_device() will change the on-disk size. */
2230         ret = btrfs_update_device(trans, device);
2231         if (ret) {
2232                 unlock_chunks(root);
2233                 btrfs_end_transaction(trans, root);
2234                 goto done;
2235         }
2236         WARN_ON(diff > old_total);
2237         btrfs_set_super_total_bytes(super_copy, old_total - diff);
2238         unlock_chunks(root);
2239         btrfs_end_transaction(trans, root);
2240 done:
2241         btrfs_free_path(path);
2242         return ret;
2243 }
2244
2245 static int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
2246                            struct btrfs_root *root,
2247                            struct btrfs_key *key,
2248                            struct btrfs_chunk *chunk, int item_size)
2249 {
2250         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
2251         struct btrfs_disk_key disk_key;
2252         u32 array_size;
2253         u8 *ptr;
2254
2255         array_size = btrfs_super_sys_array_size(super_copy);
2256         if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
2257                 return -EFBIG;
2258
2259         ptr = super_copy->sys_chunk_array + array_size;
2260         btrfs_cpu_key_to_disk(&disk_key, key);
2261         memcpy(ptr, &disk_key, sizeof(disk_key));
2262         ptr += sizeof(disk_key);
2263         memcpy(ptr, chunk, item_size);
2264         item_size += sizeof(disk_key);
2265         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
2266         return 0;
2267 }
2268
2269 /*
2270  * sort the devices in descending order by max_avail, total_avail
2271  */
2272 static int btrfs_cmp_device_info(const void *a, const void *b)
2273 {
2274         const struct btrfs_device_info *di_a = a;
2275         const struct btrfs_device_info *di_b = b;
2276
2277         if (di_a->max_avail > di_b->max_avail)
2278                 return -1;
2279         if (di_a->max_avail < di_b->max_avail)
2280                 return 1;
2281         if (di_a->total_avail > di_b->total_avail)
2282                 return -1;
2283         if (di_a->total_avail < di_b->total_avail)
2284                 return 1;
2285         return 0;
2286 }
2287
2288 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
2289                                struct btrfs_root *extent_root,
2290                                struct map_lookup **map_ret,
2291                                u64 *num_bytes_out, u64 *stripe_size_out,
2292                                u64 start, u64 type)
2293 {
2294         struct btrfs_fs_info *info = extent_root->fs_info;
2295         struct btrfs_fs_devices *fs_devices = info->fs_devices;
2296         struct list_head *cur;
2297         struct map_lookup *map = NULL;
2298         struct extent_map_tree *em_tree;
2299         struct extent_map *em;
2300         struct btrfs_device_info *devices_info = NULL;
2301         u64 total_avail;
2302         int num_stripes;        /* total number of stripes to allocate */
2303         int sub_stripes;        /* sub_stripes info for map */
2304         int dev_stripes;        /* stripes per dev */
2305         int devs_max;           /* max devs to use */
2306         int devs_min;           /* min devs needed */
2307         int devs_increment;     /* ndevs has to be a multiple of this */
2308         int ncopies;            /* how many copies to data has */
2309         int ret;
2310         u64 max_stripe_size;
2311         u64 max_chunk_size;
2312         u64 stripe_size;
2313         u64 num_bytes;
2314         int ndevs;
2315         int i;
2316         int j;
2317
2318         if ((type & BTRFS_BLOCK_GROUP_RAID1) &&
2319             (type & BTRFS_BLOCK_GROUP_DUP)) {
2320                 WARN_ON(1);
2321                 type &= ~BTRFS_BLOCK_GROUP_DUP;
2322         }
2323
2324         if (list_empty(&fs_devices->alloc_list))
2325                 return -ENOSPC;
2326
2327         sub_stripes = 1;
2328         dev_stripes = 1;
2329         devs_increment = 1;
2330         ncopies = 1;
2331         devs_max = 0;   /* 0 == as many as possible */
2332         devs_min = 1;
2333
2334         /*
2335          * define the properties of each RAID type.
2336          * FIXME: move this to a global table and use it in all RAID
2337          * calculation code
2338          */
2339         if (type & (BTRFS_BLOCK_GROUP_DUP)) {
2340                 dev_stripes = 2;
2341                 ncopies = 2;
2342                 devs_max = 1;
2343         } else if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
2344                 devs_min = 2;
2345         } else if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
2346                 devs_increment = 2;
2347                 ncopies = 2;
2348                 devs_max = 2;
2349                 devs_min = 2;
2350         } else if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
2351                 sub_stripes = 2;
2352                 devs_increment = 2;
2353                 ncopies = 2;
2354                 devs_min = 4;
2355         } else {
2356                 devs_max = 1;
2357         }
2358
2359         if (type & BTRFS_BLOCK_GROUP_DATA) {
2360                 max_stripe_size = 1024 * 1024 * 1024;
2361                 max_chunk_size = 10 * max_stripe_size;
2362         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
2363                 max_stripe_size = 256 * 1024 * 1024;
2364                 max_chunk_size = max_stripe_size;
2365         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
2366                 max_stripe_size = 8 * 1024 * 1024;
2367                 max_chunk_size = 2 * max_stripe_size;
2368         } else {
2369                 printk(KERN_ERR "btrfs: invalid chunk type 0x%llx requested\n",
2370                        type);
2371                 BUG_ON(1);
2372         }
2373
2374         /* we don't want a chunk larger than 10% of writeable space */
2375         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
2376                              max_chunk_size);
2377
2378         devices_info = kzalloc(sizeof(*devices_info) * fs_devices->rw_devices,
2379                                GFP_NOFS);
2380         if (!devices_info)
2381                 return -ENOMEM;
2382
2383         cur = fs_devices->alloc_list.next;
2384
2385         /*
2386          * in the first pass through the devices list, we gather information
2387          * about the available holes on each device.
2388          */
2389         ndevs = 0;
2390         while (cur != &fs_devices->alloc_list) {
2391                 struct btrfs_device *device;
2392                 u64 max_avail;
2393                 u64 dev_offset;
2394
2395                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
2396
2397                 cur = cur->next;
2398
2399                 if (!device->writeable) {
2400                         printk(KERN_ERR
2401                                "btrfs: read-only device in alloc_list\n");
2402                         WARN_ON(1);
2403                         continue;
2404                 }
2405
2406                 if (!device->in_fs_metadata)
2407                         continue;
2408
2409                 if (device->total_bytes > device->bytes_used)
2410                         total_avail = device->total_bytes - device->bytes_used;
2411                 else
2412                         total_avail = 0;
2413                 /* avail is off by max(alloc_start, 1MB), but that is the same
2414                  * for all devices, so it doesn't hurt the sorting later on
2415                  */
2416
2417                 ret = find_free_dev_extent(trans, device,
2418                                            max_stripe_size * dev_stripes,
2419                                            &dev_offset, &max_avail);
2420                 if (ret && ret != -ENOSPC)
2421                         goto error;
2422
2423                 if (ret == 0)
2424                         max_avail = max_stripe_size * dev_stripes;
2425
2426                 if (max_avail < BTRFS_STRIPE_LEN * dev_stripes)
2427                         continue;
2428
2429                 devices_info[ndevs].dev_offset = dev_offset;
2430                 devices_info[ndevs].max_avail = max_avail;
2431                 devices_info[ndevs].total_avail = total_avail;
2432                 devices_info[ndevs].dev = device;
2433                 ++ndevs;
2434         }
2435
2436         /*
2437          * now sort the devices by hole size / available space
2438          */
2439         sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
2440              btrfs_cmp_device_info, NULL);
2441
2442         /* round down to number of usable stripes */
2443         ndevs -= ndevs % devs_increment;
2444
2445         if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
2446                 ret = -ENOSPC;
2447                 goto error;
2448         }
2449
2450         if (devs_max && ndevs > devs_max)
2451                 ndevs = devs_max;
2452         /*
2453          * the primary goal is to maximize the number of stripes, so use as many
2454          * devices as possible, even if the stripes are not maximum sized.
2455          */
2456         stripe_size = devices_info[ndevs-1].max_avail;
2457         num_stripes = ndevs * dev_stripes;
2458
2459         if (stripe_size * num_stripes > max_chunk_size * ncopies) {
2460                 stripe_size = max_chunk_size * ncopies;
2461                 do_div(stripe_size, num_stripes);
2462         }
2463
2464         do_div(stripe_size, dev_stripes);
2465         do_div(stripe_size, BTRFS_STRIPE_LEN);
2466         stripe_size *= BTRFS_STRIPE_LEN;
2467
2468         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
2469         if (!map) {
2470                 ret = -ENOMEM;
2471                 goto error;
2472         }
2473         map->num_stripes = num_stripes;
2474
2475         for (i = 0; i < ndevs; ++i) {
2476                 for (j = 0; j < dev_stripes; ++j) {
2477                         int s = i * dev_stripes + j;
2478                         map->stripes[s].dev = devices_info[i].dev;
2479                         map->stripes[s].physical = devices_info[i].dev_offset +
2480                                                    j * stripe_size;
2481                 }
2482         }
2483         map->sector_size = extent_root->sectorsize;
2484         map->stripe_len = BTRFS_STRIPE_LEN;
2485         map->io_align = BTRFS_STRIPE_LEN;
2486         map->io_width = BTRFS_STRIPE_LEN;
2487         map->type = type;
2488         map->sub_stripes = sub_stripes;
2489
2490         *map_ret = map;
2491         num_bytes = stripe_size * (num_stripes / ncopies);
2492
2493         *stripe_size_out = stripe_size;
2494         *num_bytes_out = num_bytes;
2495
2496         trace_btrfs_chunk_alloc(info->chunk_root, map, start, num_bytes);
2497
2498         em = alloc_extent_map();
2499         if (!em) {
2500                 ret = -ENOMEM;
2501                 goto error;
2502         }
2503         em->bdev = (struct block_device *)map;
2504         em->start = start;
2505         em->len = num_bytes;
2506         em->block_start = 0;
2507         em->block_len = em->len;
2508
2509         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
2510         write_lock(&em_tree->lock);
2511         ret = add_extent_mapping(em_tree, em);
2512         write_unlock(&em_tree->lock);
2513         BUG_ON(ret);
2514         free_extent_map(em);
2515
2516         ret = btrfs_make_block_group(trans, extent_root, 0, type,
2517                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2518                                      start, num_bytes);
2519         BUG_ON(ret);
2520
2521         for (i = 0; i < map->num_stripes; ++i) {
2522                 struct btrfs_device *device;
2523                 u64 dev_offset;
2524
2525                 device = map->stripes[i].dev;
2526                 dev_offset = map->stripes[i].physical;
2527
2528                 ret = btrfs_alloc_dev_extent(trans, device,
2529                                 info->chunk_root->root_key.objectid,
2530                                 BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2531                                 start, dev_offset, stripe_size);
2532                 BUG_ON(ret);
2533         }
2534
2535         kfree(devices_info);
2536         return 0;
2537
2538 error:
2539         kfree(map);
2540         kfree(devices_info);
2541         return ret;
2542 }
2543
2544 static int __finish_chunk_alloc(struct btrfs_trans_handle *trans,
2545                                 struct btrfs_root *extent_root,
2546                                 struct map_lookup *map, u64 chunk_offset,
2547                                 u64 chunk_size, u64 stripe_size)
2548 {
2549         u64 dev_offset;
2550         struct btrfs_key key;
2551         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
2552         struct btrfs_device *device;
2553         struct btrfs_chunk *chunk;
2554         struct btrfs_stripe *stripe;
2555         size_t item_size = btrfs_chunk_item_size(map->num_stripes);
2556         int index = 0;
2557         int ret;
2558
2559         chunk = kzalloc(item_size, GFP_NOFS);
2560         if (!chunk)
2561                 return -ENOMEM;
2562
2563         index = 0;
2564         while (index < map->num_stripes) {
2565                 device = map->stripes[index].dev;
2566                 device->bytes_used += stripe_size;
2567                 ret = btrfs_update_device(trans, device);
2568                 BUG_ON(ret);
2569                 index++;
2570         }
2571
2572         index = 0;
2573         stripe = &chunk->stripe;
2574         while (index < map->num_stripes) {
2575                 device = map->stripes[index].dev;
2576                 dev_offset = map->stripes[index].physical;
2577
2578                 btrfs_set_stack_stripe_devid(stripe, device->devid);
2579                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
2580                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
2581                 stripe++;
2582                 index++;
2583         }
2584
2585         btrfs_set_stack_chunk_length(chunk, chunk_size);
2586         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
2587         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
2588         btrfs_set_stack_chunk_type(chunk, map->type);
2589         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
2590         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
2591         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
2592         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
2593         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
2594
2595         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2596         key.type = BTRFS_CHUNK_ITEM_KEY;
2597         key.offset = chunk_offset;
2598
2599         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
2600         BUG_ON(ret);
2601
2602         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2603                 ret = btrfs_add_system_chunk(trans, chunk_root, &key, chunk,
2604                                              item_size);
2605                 BUG_ON(ret);
2606         }
2607
2608         kfree(chunk);
2609         return 0;
2610 }
2611
2612 /*
2613  * Chunk allocation falls into two parts. The first part does works
2614  * that make the new allocated chunk useable, but not do any operation
2615  * that modifies the chunk tree. The second part does the works that
2616  * require modifying the chunk tree. This division is important for the
2617  * bootstrap process of adding storage to a seed btrfs.
2618  */
2619 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
2620                       struct btrfs_root *extent_root, u64 type)
2621 {
2622         u64 chunk_offset;
2623         u64 chunk_size;
2624         u64 stripe_size;
2625         struct map_lookup *map;
2626         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
2627         int ret;
2628
2629         ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2630                               &chunk_offset);
2631         if (ret)
2632                 return ret;
2633
2634         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
2635                                   &stripe_size, chunk_offset, type);
2636         if (ret)
2637                 return ret;
2638
2639         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
2640                                    chunk_size, stripe_size);
2641         BUG_ON(ret);
2642         return 0;
2643 }
2644
2645 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
2646                                          struct btrfs_root *root,
2647                                          struct btrfs_device *device)
2648 {
2649         u64 chunk_offset;
2650         u64 sys_chunk_offset;
2651         u64 chunk_size;
2652         u64 sys_chunk_size;
2653         u64 stripe_size;
2654         u64 sys_stripe_size;
2655         u64 alloc_profile;
2656         struct map_lookup *map;
2657         struct map_lookup *sys_map;
2658         struct btrfs_fs_info *fs_info = root->fs_info;
2659         struct btrfs_root *extent_root = fs_info->extent_root;
2660         int ret;
2661
2662         ret = find_next_chunk(fs_info->chunk_root,
2663                               BTRFS_FIRST_CHUNK_TREE_OBJECTID, &chunk_offset);
2664         BUG_ON(ret);
2665
2666         alloc_profile = BTRFS_BLOCK_GROUP_METADATA |
2667                         (fs_info->metadata_alloc_profile &
2668                          fs_info->avail_metadata_alloc_bits);
2669         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
2670
2671         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
2672                                   &stripe_size, chunk_offset, alloc_profile);
2673         BUG_ON(ret);
2674
2675         sys_chunk_offset = chunk_offset + chunk_size;
2676
2677         alloc_profile = BTRFS_BLOCK_GROUP_SYSTEM |
2678                         (fs_info->system_alloc_profile &
2679                          fs_info->avail_system_alloc_bits);
2680         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
2681
2682         ret = __btrfs_alloc_chunk(trans, extent_root, &sys_map,
2683                                   &sys_chunk_size, &sys_stripe_size,
2684                                   sys_chunk_offset, alloc_profile);
2685         BUG_ON(ret);
2686
2687         ret = btrfs_add_device(trans, fs_info->chunk_root, device);
2688         BUG_ON(ret);
2689
2690         /*
2691          * Modifying chunk tree needs allocating new blocks from both
2692          * system block group and metadata block group. So we only can
2693          * do operations require modifying the chunk tree after both
2694          * block groups were created.
2695          */
2696         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
2697                                    chunk_size, stripe_size);
2698         BUG_ON(ret);
2699
2700         ret = __finish_chunk_alloc(trans, extent_root, sys_map,
2701                                    sys_chunk_offset, sys_chunk_size,
2702                                    sys_stripe_size);
2703         BUG_ON(ret);
2704         return 0;
2705 }
2706
2707 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
2708 {
2709         struct extent_map *em;
2710         struct map_lookup *map;
2711         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
2712         int readonly = 0;
2713         int i;
2714
2715         read_lock(&map_tree->map_tree.lock);
2716         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
2717         read_unlock(&map_tree->map_tree.lock);
2718         if (!em)
2719                 return 1;
2720
2721         if (btrfs_test_opt(root, DEGRADED)) {
2722                 free_extent_map(em);
2723                 return 0;
2724         }
2725
2726         map = (struct map_lookup *)em->bdev;
2727         for (i = 0; i < map->num_stripes; i++) {
2728                 if (!map->stripes[i].dev->writeable) {
2729                         readonly = 1;
2730                         break;
2731                 }
2732         }
2733         free_extent_map(em);
2734         return readonly;
2735 }
2736
2737 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
2738 {
2739         extent_map_tree_init(&tree->map_tree);
2740 }
2741
2742 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
2743 {
2744         struct extent_map *em;
2745
2746         while (1) {
2747                 write_lock(&tree->map_tree.lock);
2748                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
2749                 if (em)
2750                         remove_extent_mapping(&tree->map_tree, em);
2751                 write_unlock(&tree->map_tree.lock);
2752                 if (!em)
2753                         break;
2754                 kfree(em->bdev);
2755                 /* once for us */
2756                 free_extent_map(em);
2757                 /* once for the tree */
2758                 free_extent_map(em);
2759         }
2760 }
2761
2762 int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
2763 {
2764         struct extent_map *em;
2765         struct map_lookup *map;
2766         struct extent_map_tree *em_tree = &map_tree->map_tree;
2767         int ret;
2768
2769         read_lock(&em_tree->lock);
2770         em = lookup_extent_mapping(em_tree, logical, len);
2771         read_unlock(&em_tree->lock);
2772         BUG_ON(!em);
2773
2774         BUG_ON(em->start > logical || em->start + em->len < logical);
2775         map = (struct map_lookup *)em->bdev;
2776         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
2777                 ret = map->num_stripes;
2778         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
2779                 ret = map->sub_stripes;
2780         else
2781                 ret = 1;
2782         free_extent_map(em);
2783         return ret;
2784 }
2785
2786 static int find_live_mirror(struct map_lookup *map, int first, int num,
2787                             int optimal)
2788 {
2789         int i;
2790         if (map->stripes[optimal].dev->bdev)
2791                 return optimal;
2792         for (i = first; i < first + num; i++) {
2793                 if (map->stripes[i].dev->bdev)
2794                         return i;
2795         }
2796         /* we couldn't find one that doesn't fail.  Just return something
2797          * and the io error handling code will clean up eventually
2798          */
2799         return optimal;
2800 }
2801
2802 static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
2803                              u64 logical, u64 *length,
2804                              struct btrfs_multi_bio **multi_ret,
2805                              int mirror_num)
2806 {
2807         struct extent_map *em;
2808         struct map_lookup *map;
2809         struct extent_map_tree *em_tree = &map_tree->map_tree;
2810         u64 offset;
2811         u64 stripe_offset;
2812         u64 stripe_end_offset;
2813         u64 stripe_nr;
2814         u64 stripe_nr_orig;
2815         u64 stripe_nr_end;
2816         int stripes_allocated = 8;
2817         int stripes_required = 1;
2818         int stripe_index;
2819         int i;
2820         int num_stripes;
2821         int max_errors = 0;
2822         struct btrfs_multi_bio *multi = NULL;
2823
2824         if (multi_ret && !(rw & (REQ_WRITE | REQ_DISCARD)))
2825                 stripes_allocated = 1;
2826 again:
2827         if (multi_ret) {
2828                 multi = kzalloc(btrfs_multi_bio_size(stripes_allocated),
2829                                 GFP_NOFS);
2830                 if (!multi)
2831                         return -ENOMEM;
2832
2833                 atomic_set(&multi->error, 0);
2834         }
2835
2836         read_lock(&em_tree->lock);
2837         em = lookup_extent_mapping(em_tree, logical, *length);
2838         read_unlock(&em_tree->lock);
2839
2840         if (!em) {
2841                 printk(KERN_CRIT "unable to find logical %llu len %llu\n",
2842                        (unsigned long long)logical,
2843                        (unsigned long long)*length);
2844                 BUG();
2845         }
2846
2847         BUG_ON(em->start > logical || em->start + em->len < logical);
2848         map = (struct map_lookup *)em->bdev;
2849         offset = logical - em->start;
2850
2851         if (mirror_num > map->num_stripes)
2852                 mirror_num = 0;
2853
2854         /* if our multi bio struct is too small, back off and try again */
2855         if (rw & REQ_WRITE) {
2856                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
2857                                  BTRFS_BLOCK_GROUP_DUP)) {
2858                         stripes_required = map->num_stripes;
2859                         max_errors = 1;
2860                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
2861                         stripes_required = map->sub_stripes;
2862                         max_errors = 1;
2863                 }
2864         }
2865         if (rw & REQ_DISCARD) {
2866                 if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
2867                                  BTRFS_BLOCK_GROUP_RAID1 |
2868                                  BTRFS_BLOCK_GROUP_DUP |
2869                                  BTRFS_BLOCK_GROUP_RAID10)) {
2870                         stripes_required = map->num_stripes;
2871                 }
2872         }
2873         if (multi_ret && (rw & (REQ_WRITE | REQ_DISCARD)) &&
2874             stripes_allocated < stripes_required) {
2875                 stripes_allocated = map->num_stripes;
2876                 free_extent_map(em);
2877                 kfree(multi);
2878                 goto again;
2879         }
2880         stripe_nr = offset;
2881         /*
2882          * stripe_nr counts the total number of stripes we have to stride
2883          * to get to this block
2884          */
2885         do_div(stripe_nr, map->stripe_len);
2886
2887         stripe_offset = stripe_nr * map->stripe_len;
2888         BUG_ON(offset < stripe_offset);
2889
2890         /* stripe_offset is the offset of this block in its stripe*/
2891         stripe_offset = offset - stripe_offset;
2892
2893         if (rw & REQ_DISCARD)
2894                 *length = min_t(u64, em->len - offset, *length);
2895         else if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
2896                               BTRFS_BLOCK_GROUP_RAID1 |
2897                               BTRFS_BLOCK_GROUP_RAID10 |
2898                               BTRFS_BLOCK_GROUP_DUP)) {
2899                 /* we limit the length of each bio to what fits in a stripe */
2900                 *length = min_t(u64, em->len - offset,
2901                                 map->stripe_len - stripe_offset);
2902         } else {
2903                 *length = em->len - offset;
2904         }
2905
2906         if (!multi_ret)
2907                 goto out;
2908
2909         num_stripes = 1;
2910         stripe_index = 0;
2911         stripe_nr_orig = stripe_nr;
2912         stripe_nr_end = (offset + *length + map->stripe_len - 1) &
2913                         (~(map->stripe_len - 1));
2914         do_div(stripe_nr_end, map->stripe_len);
2915         stripe_end_offset = stripe_nr_end * map->stripe_len -
2916                             (offset + *length);
2917         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
2918                 if (rw & REQ_DISCARD)
2919                         num_stripes = min_t(u64, map->num_stripes,
2920                                             stripe_nr_end - stripe_nr_orig);
2921                 stripe_index = do_div(stripe_nr, map->num_stripes);
2922         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
2923                 if (rw & (REQ_WRITE | REQ_DISCARD))
2924                         num_stripes = map->num_stripes;
2925                 else if (mirror_num)
2926                         stripe_index = mirror_num - 1;
2927                 else {
2928                         stripe_index = find_live_mirror(map, 0,
2929                                             map->num_stripes,
2930                                             current->pid % map->num_stripes);
2931                 }
2932
2933         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
2934                 if (rw & (REQ_WRITE | REQ_DISCARD))
2935                         num_stripes = map->num_stripes;
2936                 else if (mirror_num)
2937                         stripe_index = mirror_num - 1;
2938
2939         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
2940                 int factor = map->num_stripes / map->sub_stripes;
2941
2942                 stripe_index = do_div(stripe_nr, factor);
2943                 stripe_index *= map->sub_stripes;
2944
2945                 if (rw & REQ_WRITE)
2946                         num_stripes = map->sub_stripes;
2947                 else if (rw & REQ_DISCARD)
2948                         num_stripes = min_t(u64, map->sub_stripes *
2949                                             (stripe_nr_end - stripe_nr_orig),
2950                                             map->num_stripes);
2951                 else if (mirror_num)
2952                         stripe_index += mirror_num - 1;
2953                 else {
2954                         stripe_index = find_live_mirror(map, stripe_index,
2955                                               map->sub_stripes, stripe_index +
2956                                               current->pid % map->sub_stripes);
2957                 }
2958         } else {
2959                 /*
2960                  * after this do_div call, stripe_nr is the number of stripes
2961                  * on this device we have to walk to find the data, and
2962                  * stripe_index is the number of our device in the stripe array
2963                  */
2964                 stripe_index = do_div(stripe_nr, map->num_stripes);
2965         }
2966         BUG_ON(stripe_index >= map->num_stripes);
2967
2968         if (rw & REQ_DISCARD) {
2969                 for (i = 0; i < num_stripes; i++) {
2970                         multi->stripes[i].physical =
2971                                 map->stripes[stripe_index].physical +
2972                                 stripe_offset + stripe_nr * map->stripe_len;
2973                         multi->stripes[i].dev = map->stripes[stripe_index].dev;
2974
2975                         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
2976                                 u64 stripes;
2977                                 u32 last_stripe = 0;
2978                                 int j;
2979
2980                                 div_u64_rem(stripe_nr_end - 1,
2981                                             map->num_stripes,
2982                                             &last_stripe);
2983
2984                                 for (j = 0; j < map->num_stripes; j++) {
2985                                         u32 test;
2986
2987                                         div_u64_rem(stripe_nr_end - 1 - j,
2988                                                     map->num_stripes, &test);
2989                                         if (test == stripe_index)
2990                                                 break;
2991                                 }
2992                                 stripes = stripe_nr_end - 1 - j;
2993                                 do_div(stripes, map->num_stripes);
2994                                 multi->stripes[i].length = map->stripe_len *
2995                                         (stripes - stripe_nr + 1);
2996
2997                                 if (i == 0) {
2998                                         multi->stripes[i].length -=
2999                                                 stripe_offset;
3000                                         stripe_offset = 0;
3001                                 }
3002                                 if (stripe_index == last_stripe)
3003                                         multi->stripes[i].length -=
3004                                                 stripe_end_offset;
3005                         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
3006                                 u64 stripes;
3007                                 int j;
3008                                 int factor = map->num_stripes /
3009                                              map->sub_stripes;
3010                                 u32 last_stripe = 0;
3011
3012                                 div_u64_rem(stripe_nr_end - 1,
3013                                             factor, &last_stripe);
3014                                 last_stripe *= map->sub_stripes;
3015
3016                                 for (j = 0; j < factor; j++) {
3017                                         u32 test;
3018
3019                                         div_u64_rem(stripe_nr_end - 1 - j,
3020                                                     factor, &test);
3021
3022                                         if (test ==
3023                                             stripe_index / map->sub_stripes)
3024                                                 break;
3025                                 }
3026                                 stripes = stripe_nr_end - 1 - j;
3027                                 do_div(stripes, factor);
3028                                 multi->stripes[i].length = map->stripe_len *
3029                                         (stripes - stripe_nr + 1);
3030
3031                                 if (i < map->sub_stripes) {
3032                                         multi->stripes[i].length -=
3033                                                 stripe_offset;
3034                                         if (i == map->sub_stripes - 1)
3035                                                 stripe_offset = 0;
3036                                 }
3037                                 if (stripe_index >= last_stripe &&
3038                                     stripe_index <= (last_stripe +
3039                                                      map->sub_stripes - 1)) {
3040                                         multi->stripes[i].length -=
3041                                                 stripe_end_offset;
3042                                 }
3043                         } else
3044                                 multi->stripes[i].length = *length;
3045
3046                         stripe_index++;
3047                         if (stripe_index == map->num_stripes) {
3048                                 /* This could only happen for RAID0/10 */
3049                                 stripe_index = 0;
3050                                 stripe_nr++;
3051                         }
3052                 }
3053         } else {
3054                 for (i = 0; i < num_stripes; i++) {
3055                         multi->stripes[i].physical =
3056                                 map->stripes[stripe_index].physical +
3057                                 stripe_offset +
3058                                 stripe_nr * map->stripe_len;
3059                         multi->stripes[i].dev =
3060                                 map->stripes[stripe_index].dev;
3061                         stripe_index++;
3062                 }
3063         }
3064         if (multi_ret) {
3065                 *multi_ret = multi;
3066                 multi->num_stripes = num_stripes;
3067                 multi->max_errors = max_errors;
3068         }
3069 out:
3070         free_extent_map(em);
3071         return 0;
3072 }
3073
3074 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
3075                       u64 logical, u64 *length,
3076                       struct btrfs_multi_bio **multi_ret, int mirror_num)
3077 {
3078         return __btrfs_map_block(map_tree, rw, logical, length, multi_ret,
3079                                  mirror_num);
3080 }
3081
3082 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
3083                      u64 chunk_start, u64 physical, u64 devid,
3084                      u64 **logical, int *naddrs, int *stripe_len)
3085 {
3086         struct extent_map_tree *em_tree = &map_tree->map_tree;
3087         struct extent_map *em;
3088         struct map_lookup *map;
3089         u64 *buf;
3090         u64 bytenr;
3091         u64 length;
3092         u64 stripe_nr;
3093         int i, j, nr = 0;
3094
3095         read_lock(&em_tree->lock);
3096         em = lookup_extent_mapping(em_tree, chunk_start, 1);
3097         read_unlock(&em_tree->lock);
3098
3099         BUG_ON(!em || em->start != chunk_start);
3100         map = (struct map_lookup *)em->bdev;
3101
3102         length = em->len;
3103         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
3104                 do_div(length, map->num_stripes / map->sub_stripes);
3105         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
3106                 do_div(length, map->num_stripes);
3107
3108         buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
3109         BUG_ON(!buf);
3110
3111         for (i = 0; i < map->num_stripes; i++) {
3112                 if (devid && map->stripes[i].dev->devid != devid)
3113                         continue;
3114                 if (map->stripes[i].physical > physical ||
3115                     map->stripes[i].physical + length <= physical)
3116                         continue;
3117
3118                 stripe_nr = physical - map->stripes[i].physical;
3119                 do_div(stripe_nr, map->stripe_len);
3120
3121                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
3122                         stripe_nr = stripe_nr * map->num_stripes + i;
3123                         do_div(stripe_nr, map->sub_stripes);
3124                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
3125                         stripe_nr = stripe_nr * map->num_stripes + i;
3126                 }
3127                 bytenr = chunk_start + stripe_nr * map->stripe_len;
3128                 WARN_ON(nr >= map->num_stripes);
3129                 for (j = 0; j < nr; j++) {
3130                         if (buf[j] == bytenr)
3131                                 break;
3132                 }
3133                 if (j == nr) {
3134                         WARN_ON(nr >= map->num_stripes);
3135                         buf[nr++] = bytenr;
3136                 }
3137         }
3138
3139         *logical = buf;
3140         *naddrs = nr;
3141         *stripe_len = map->stripe_len;
3142
3143         free_extent_map(em);
3144         return 0;
3145 }
3146
3147 static void end_bio_multi_stripe(struct bio *bio, int err)
3148 {
3149         struct btrfs_multi_bio *multi = bio->bi_private;
3150         int is_orig_bio = 0;
3151
3152         if (err)
3153                 atomic_inc(&multi->error);
3154
3155         if (bio == multi->orig_bio)
3156                 is_orig_bio = 1;
3157
3158         if (atomic_dec_and_test(&multi->stripes_pending)) {
3159                 if (!is_orig_bio) {
3160                         bio_put(bio);
3161                         bio = multi->orig_bio;
3162                 }
3163                 bio->bi_private = multi->private;
3164                 bio->bi_end_io = multi->end_io;
3165                 /* only send an error to the higher layers if it is
3166                  * beyond the tolerance of the multi-bio
3167                  */
3168                 if (atomic_read(&multi->error) > multi->max_errors) {
3169                         err = -EIO;
3170                 } else if (err) {
3171                         /*
3172                          * this bio is actually up to date, we didn't
3173                          * go over the max number of errors
3174                          */
3175                         set_bit(BIO_UPTODATE, &bio->bi_flags);
3176                         err = 0;
3177                 }
3178                 kfree(multi);
3179
3180                 bio_endio(bio, err);
3181         } else if (!is_orig_bio) {
3182                 bio_put(bio);
3183         }
3184 }
3185
3186 struct async_sched {
3187         struct bio *bio;
3188         int rw;
3189         struct btrfs_fs_info *info;
3190         struct btrfs_work work;
3191 };
3192
3193 /*
3194  * see run_scheduled_bios for a description of why bios are collected for
3195  * async submit.
3196  *
3197  * This will add one bio to the pending list for a device and make sure
3198  * the work struct is scheduled.
3199  */
3200 static noinline int schedule_bio(struct btrfs_root *root,
3201                                  struct btrfs_device *device,
3202                                  int rw, struct bio *bio)
3203 {
3204         int should_queue = 1;
3205         struct btrfs_pending_bios *pending_bios;
3206
3207         /* don't bother with additional async steps for reads, right now */
3208         if (!(rw & REQ_WRITE)) {
3209                 bio_get(bio);
3210                 submit_bio(rw, bio);
3211                 bio_put(bio);
3212                 return 0;
3213         }
3214
3215         /*
3216          * nr_async_bios allows us to reliably return congestion to the
3217          * higher layers.  Otherwise, the async bio makes it appear we have
3218          * made progress against dirty pages when we've really just put it
3219          * on a queue for later
3220          */
3221         atomic_inc(&root->fs_info->nr_async_bios);
3222         WARN_ON(bio->bi_next);
3223         bio->bi_next = NULL;
3224         bio->bi_rw |= rw;
3225
3226         spin_lock(&device->io_lock);
3227         if (bio->bi_rw & REQ_SYNC)
3228                 pending_bios = &device->pending_sync_bios;
3229         else
3230                 pending_bios = &device->pending_bios;
3231
3232         if (pending_bios->tail)
3233                 pending_bios->tail->bi_next = bio;
3234
3235         pending_bios->tail = bio;
3236         if (!pending_bios->head)
3237                 pending_bios->head = bio;
3238         if (device->running_pending)
3239                 should_queue = 0;
3240
3241         spin_unlock(&device->io_lock);
3242
3243         if (should_queue)
3244                 btrfs_queue_worker(&root->fs_info->submit_workers,
3245                                    &device->work);
3246         return 0;
3247 }
3248
3249 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
3250                   int mirror_num, int async_submit)
3251 {
3252         struct btrfs_mapping_tree *map_tree;
3253         struct btrfs_device *dev;
3254         struct bio *first_bio = bio;
3255         u64 logical = (u64)bio->bi_sector << 9;
3256         u64 length = 0;
3257         u64 map_length;
3258         struct btrfs_multi_bio *multi = NULL;
3259         int ret;
3260         int dev_nr = 0;
3261         int total_devs = 1;
3262
3263         length = bio->bi_size;
3264         map_tree = &root->fs_info->mapping_tree;
3265         map_length = length;
3266
3267         ret = btrfs_map_block(map_tree, rw, logical, &map_length, &multi,
3268                               mirror_num);
3269         BUG_ON(ret);
3270
3271         total_devs = multi->num_stripes;
3272         if (map_length < length) {
3273                 printk(KERN_CRIT "mapping failed logical %llu bio len %llu "
3274                        "len %llu\n", (unsigned long long)logical,
3275                        (unsigned long long)length,
3276                        (unsigned long long)map_length);
3277                 BUG();
3278         }
3279         multi->end_io = first_bio->bi_end_io;
3280         multi->private = first_bio->bi_private;
3281         multi->orig_bio = first_bio;
3282         atomic_set(&multi->stripes_pending, multi->num_stripes);
3283
3284         while (dev_nr < total_devs) {
3285                 if (total_devs > 1) {
3286                         if (dev_nr < total_devs - 1) {
3287                                 bio = bio_clone(first_bio, GFP_NOFS);
3288                                 BUG_ON(!bio);
3289                         } else {
3290                                 bio = first_bio;
3291                         }
3292                         bio->bi_private = multi;
3293                         bio->bi_end_io = end_bio_multi_stripe;
3294                 }
3295                 bio->bi_sector = multi->stripes[dev_nr].physical >> 9;
3296                 dev = multi->stripes[dev_nr].dev;
3297                 if (dev && dev->bdev && (rw != WRITE || dev->writeable)) {
3298                         bio->bi_bdev = dev->bdev;
3299                         if (async_submit)
3300                                 schedule_bio(root, dev, rw, bio);
3301                         else
3302                                 submit_bio(rw, bio);
3303                 } else {
3304                         bio->bi_bdev = root->fs_info->fs_devices->latest_bdev;
3305                         bio->bi_sector = logical >> 9;
3306                         bio_endio(bio, -EIO);
3307                 }
3308                 dev_nr++;
3309         }
3310         if (total_devs == 1)
3311                 kfree(multi);
3312         return 0;
3313 }
3314
3315 struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
3316                                        u8 *uuid, u8 *fsid)
3317 {
3318         struct btrfs_device *device;
3319         struct btrfs_fs_devices *cur_devices;
3320
3321         cur_devices = root->fs_info->fs_devices;
3322         while (cur_devices) {
3323                 if (!fsid ||
3324                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
3325                         device = __find_device(&cur_devices->devices,
3326                                                devid, uuid);
3327                         if (device)
3328                                 return device;
3329                 }
3330                 cur_devices = cur_devices->seed;
3331         }
3332         return NULL;
3333 }
3334
3335 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
3336                                             u64 devid, u8 *dev_uuid)
3337 {
3338         struct btrfs_device *device;
3339         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
3340
3341         device = kzalloc(sizeof(*device), GFP_NOFS);
3342         if (!device)
3343                 return NULL;
3344         list_add(&device->dev_list,
3345                  &fs_devices->devices);
3346         device->dev_root = root->fs_info->dev_root;
3347         device->devid = devid;
3348         device->work.func = pending_bios_fn;
3349         device->fs_devices = fs_devices;
3350         device->missing = 1;
3351         fs_devices->num_devices++;
3352         fs_devices->missing_devices++;
3353         spin_lock_init(&device->io_lock);
3354         INIT_LIST_HEAD(&device->dev_alloc_list);
3355         memcpy(device->uuid, dev_uuid, BTRFS_UUID_SIZE);
3356         return device;
3357 }
3358
3359 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
3360                           struct extent_buffer *leaf,
3361                           struct btrfs_chunk *chunk)
3362 {
3363         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
3364         struct map_lookup *map;
3365         struct extent_map *em;
3366         u64 logical;
3367         u64 length;
3368         u64 devid;
3369         u8 uuid[BTRFS_UUID_SIZE];
3370         int num_stripes;
3371         int ret;
3372         int i;
3373
3374         logical = key->offset;
3375         length = btrfs_chunk_length(leaf, chunk);
3376
3377         read_lock(&map_tree->map_tree.lock);
3378         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
3379         read_unlock(&map_tree->map_tree.lock);
3380
3381         /* already mapped? */
3382         if (em && em->start <= logical && em->start + em->len > logical) {
3383                 free_extent_map(em);
3384                 return 0;
3385         } else if (em) {
3386                 free_extent_map(em);
3387         }
3388
3389         em = alloc_extent_map();
3390         if (!em)
3391                 return -ENOMEM;
3392         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3393         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
3394         if (!map) {
3395                 free_extent_map(em);
3396                 return -ENOMEM;
3397         }
3398
3399         em->bdev = (struct block_device *)map;
3400         em->start = logical;
3401         em->len = length;
3402         em->block_start = 0;
3403         em->block_len = em->len;
3404
3405         map->num_stripes = num_stripes;
3406         map->io_width = btrfs_chunk_io_width(leaf, chunk);
3407         map->io_align = btrfs_chunk_io_align(leaf, chunk);
3408         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
3409         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
3410         map->type = btrfs_chunk_type(leaf, chunk);
3411         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
3412         for (i = 0; i < num_stripes; i++) {
3413                 map->stripes[i].physical =
3414                         btrfs_stripe_offset_nr(leaf, chunk, i);
3415                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
3416                 read_extent_buffer(leaf, uuid, (unsigned long)
3417                                    btrfs_stripe_dev_uuid_nr(chunk, i),
3418                                    BTRFS_UUID_SIZE);
3419                 map->stripes[i].dev = btrfs_find_device(root, devid, uuid,
3420                                                         NULL);
3421                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
3422                         kfree(map);
3423                         free_extent_map(em);
3424                         return -EIO;
3425                 }
3426                 if (!map->stripes[i].dev) {
3427                         map->stripes[i].dev =
3428                                 add_missing_dev(root, devid, uuid);
3429                         if (!map->stripes[i].dev) {
3430                                 kfree(map);
3431                                 free_extent_map(em);
3432                                 return -EIO;
3433                         }
3434                 }
3435                 map->stripes[i].dev->in_fs_metadata = 1;
3436         }
3437
3438         write_lock(&map_tree->map_tree.lock);
3439         ret = add_extent_mapping(&map_tree->map_tree, em);
3440         write_unlock(&map_tree->map_tree.lock);
3441         BUG_ON(ret);
3442         free_extent_map(em);
3443
3444         return 0;
3445 }
3446
3447 static int fill_device_from_item(struct extent_buffer *leaf,
3448                                  struct btrfs_dev_item *dev_item,
3449                                  struct btrfs_device *device)
3450 {
3451         unsigned long ptr;
3452
3453         device->devid = btrfs_device_id(leaf, dev_item);
3454         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
3455         device->total_bytes = device->disk_total_bytes;
3456         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
3457         device->type = btrfs_device_type(leaf, dev_item);
3458         device->io_align = btrfs_device_io_align(leaf, dev_item);
3459         device->io_width = btrfs_device_io_width(leaf, dev_item);
3460         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
3461
3462         ptr = (unsigned long)btrfs_device_uuid(dev_item);
3463         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
3464
3465         return 0;
3466 }
3467
3468 static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
3469 {
3470         struct btrfs_fs_devices *fs_devices;
3471         int ret;
3472
3473         mutex_lock(&uuid_mutex);
3474
3475         fs_devices = root->fs_info->fs_devices->seed;
3476         while (fs_devices) {
3477                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
3478                         ret = 0;
3479                         goto out;
3480                 }
3481                 fs_devices = fs_devices->seed;
3482         }
3483
3484         fs_devices = find_fsid(fsid);
3485         if (!fs_devices) {
3486                 ret = -ENOENT;
3487                 goto out;
3488         }
3489
3490         fs_devices = clone_fs_devices(fs_devices);
3491         if (IS_ERR(fs_devices)) {
3492                 ret = PTR_ERR(fs_devices);
3493                 goto out;
3494         }
3495
3496         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
3497                                    root->fs_info->bdev_holder);
3498         if (ret)
3499                 goto out;
3500
3501         if (!fs_devices->seeding) {
3502                 __btrfs_close_devices(fs_devices);
3503                 free_fs_devices(fs_devices);
3504                 ret = -EINVAL;
3505                 goto out;
3506         }
3507
3508         fs_devices->seed = root->fs_info->fs_devices->seed;
3509         root->fs_info->fs_devices->seed = fs_devices;
3510 out:
3511         mutex_unlock(&uuid_mutex);
3512         return ret;
3513 }
3514
3515 static int read_one_dev(struct btrfs_root *root,
3516                         struct extent_buffer *leaf,
3517                         struct btrfs_dev_item *dev_item)
3518 {
3519         struct btrfs_device *device;
3520         u64 devid;
3521         int ret;
3522         u8 fs_uuid[BTRFS_UUID_SIZE];
3523         u8 dev_uuid[BTRFS_UUID_SIZE];
3524
3525         devid = btrfs_device_id(leaf, dev_item);
3526         read_extent_buffer(leaf, dev_uuid,
3527                            (unsigned long)btrfs_device_uuid(dev_item),
3528                            BTRFS_UUID_SIZE);
3529         read_extent_buffer(leaf, fs_uuid,
3530                            (unsigned long)btrfs_device_fsid(dev_item),
3531                            BTRFS_UUID_SIZE);
3532
3533         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
3534                 ret = open_seed_devices(root, fs_uuid);
3535                 if (ret && !btrfs_test_opt(root, DEGRADED))
3536                         return ret;
3537         }
3538
3539         device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
3540         if (!device || !device->bdev) {
3541                 if (!btrfs_test_opt(root, DEGRADED))
3542                         return -EIO;
3543
3544                 if (!device) {
3545                         printk(KERN_WARNING "warning devid %llu missing\n",
3546                                (unsigned long long)devid);
3547                         device = add_missing_dev(root, devid, dev_uuid);
3548                         if (!device)
3549                                 return -ENOMEM;
3550                 } else if (!device->missing) {
3551                         /*
3552                          * this happens when a device that was properly setup
3553                          * in the device info lists suddenly goes bad.
3554                          * device->bdev is NULL, and so we have to set
3555                          * device->missing to one here
3556                          */
3557                         root->fs_info->fs_devices->missing_devices++;
3558                         device->missing = 1;
3559                 }
3560         }
3561
3562         if (device->fs_devices != root->fs_info->fs_devices) {
3563                 BUG_ON(device->writeable);
3564                 if (device->generation !=
3565                     btrfs_device_generation(leaf, dev_item))
3566                         return -EINVAL;
3567         }
3568
3569         fill_device_from_item(leaf, dev_item, device);
3570         device->dev_root = root->fs_info->dev_root;
3571         device->in_fs_metadata = 1;
3572         if (device->writeable)
3573                 device->fs_devices->total_rw_bytes += device->total_bytes;
3574         ret = 0;
3575         return ret;
3576 }
3577
3578 int btrfs_read_sys_array(struct btrfs_root *root)
3579 {
3580         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
3581         struct extent_buffer *sb;
3582         struct btrfs_disk_key *disk_key;
3583         struct btrfs_chunk *chunk;
3584         u8 *ptr;
3585         unsigned long sb_ptr;
3586         int ret = 0;
3587         u32 num_stripes;
3588         u32 array_size;
3589         u32 len = 0;
3590         u32 cur;
3591         struct btrfs_key key;
3592
3593         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
3594                                           BTRFS_SUPER_INFO_SIZE);
3595         if (!sb)
3596                 return -ENOMEM;
3597         btrfs_set_buffer_uptodate(sb);
3598         btrfs_set_buffer_lockdep_class(sb, 0);
3599
3600         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
3601         array_size = btrfs_super_sys_array_size(super_copy);
3602
3603         ptr = super_copy->sys_chunk_array;
3604         sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
3605         cur = 0;
3606
3607         while (cur < array_size) {
3608                 disk_key = (struct btrfs_disk_key *)ptr;
3609                 btrfs_disk_key_to_cpu(&key, disk_key);
3610
3611                 len = sizeof(*disk_key); ptr += len;
3612                 sb_ptr += len;
3613                 cur += len;
3614
3615                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
3616                         chunk = (struct btrfs_chunk *)sb_ptr;
3617                         ret = read_one_chunk(root, &key, sb, chunk);
3618                         if (ret)
3619                                 break;
3620                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
3621                         len = btrfs_chunk_item_size(num_stripes);
3622                 } else {
3623                         ret = -EIO;
3624                         break;
3625                 }
3626                 ptr += len;
3627                 sb_ptr += len;
3628                 cur += len;
3629         }
3630         free_extent_buffer(sb);
3631         return ret;
3632 }
3633
3634 int btrfs_read_chunk_tree(struct btrfs_root *root)
3635 {
3636         struct btrfs_path *path;
3637         struct extent_buffer *leaf;
3638         struct btrfs_key key;
3639         struct btrfs_key found_key;
3640         int ret;
3641         int slot;
3642
3643         root = root->fs_info->chunk_root;
3644
3645         path = btrfs_alloc_path();
3646         if (!path)
3647                 return -ENOMEM;
3648
3649         /* first we search for all of the device items, and then we
3650          * read in all of the chunk items.  This way we can create chunk
3651          * mappings that reference all of the devices that are afound
3652          */
3653         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
3654         key.offset = 0;
3655         key.type = 0;
3656 again:
3657         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3658         if (ret < 0)
3659                 goto error;
3660         while (1) {
3661                 leaf = path->nodes[0];
3662                 slot = path->slots[0];
3663                 if (slot >= btrfs_header_nritems(leaf)) {
3664                         ret = btrfs_next_leaf(root, path);
3665                         if (ret == 0)
3666                                 continue;
3667                         if (ret < 0)
3668                                 goto error;
3669                         break;
3670                 }
3671                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3672                 if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
3673                         if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
3674                                 break;
3675                         if (found_key.type == BTRFS_DEV_ITEM_KEY) {
3676                                 struct btrfs_dev_item *dev_item;
3677                                 dev_item = btrfs_item_ptr(leaf, slot,
3678                                                   struct btrfs_dev_item);
3679                                 ret = read_one_dev(root, leaf, dev_item);
3680                                 if (ret)
3681                                         goto error;
3682                         }
3683                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
3684                         struct btrfs_chunk *chunk;
3685                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
3686                         ret = read_one_chunk(root, &found_key, leaf, chunk);
3687                         if (ret)
3688                                 goto error;
3689                 }
3690                 path->slots[0]++;
3691         }
3692         if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
3693                 key.objectid = 0;
3694                 btrfs_release_path(path);
3695                 goto again;
3696         }
3697         ret = 0;
3698 error:
3699         btrfs_free_path(path);
3700         return ret;
3701 }