Btrfs: Remove broken sanity check from btrfs_rmap_block()
[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/buffer_head.h>
21 #include <linux/blkdev.h>
22 #include <linux/random.h>
23 #include <linux/iocontext.h>
24 #include <asm/div64.h>
25 #include "compat.h"
26 #include "ctree.h"
27 #include "extent_map.h"
28 #include "disk-io.h"
29 #include "transaction.h"
30 #include "print-tree.h"
31 #include "volumes.h"
32 #include "async-thread.h"
33
34 struct map_lookup {
35         u64 type;
36         int io_align;
37         int io_width;
38         int stripe_len;
39         int sector_size;
40         int num_stripes;
41         int sub_stripes;
42         struct btrfs_bio_stripe stripes[];
43 };
44
45 static int init_first_rw_device(struct btrfs_trans_handle *trans,
46                                 struct btrfs_root *root,
47                                 struct btrfs_device *device);
48 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
49
50 #define map_lookup_size(n) (sizeof(struct map_lookup) + \
51                             (sizeof(struct btrfs_bio_stripe) * (n)))
52
53 static DEFINE_MUTEX(uuid_mutex);
54 static LIST_HEAD(fs_uuids);
55
56 void btrfs_lock_volumes(void)
57 {
58         mutex_lock(&uuid_mutex);
59 }
60
61 void btrfs_unlock_volumes(void)
62 {
63         mutex_unlock(&uuid_mutex);
64 }
65
66 static void lock_chunks(struct btrfs_root *root)
67 {
68         mutex_lock(&root->fs_info->chunk_mutex);
69 }
70
71 static void unlock_chunks(struct btrfs_root *root)
72 {
73         mutex_unlock(&root->fs_info->chunk_mutex);
74 }
75
76 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
77 {
78         struct btrfs_device *device;
79         WARN_ON(fs_devices->opened);
80         while (!list_empty(&fs_devices->devices)) {
81                 device = list_entry(fs_devices->devices.next,
82                                     struct btrfs_device, dev_list);
83                 list_del(&device->dev_list);
84                 kfree(device->name);
85                 kfree(device);
86         }
87         kfree(fs_devices);
88 }
89
90 int btrfs_cleanup_fs_uuids(void)
91 {
92         struct btrfs_fs_devices *fs_devices;
93
94         while (!list_empty(&fs_uuids)) {
95                 fs_devices = list_entry(fs_uuids.next,
96                                         struct btrfs_fs_devices, list);
97                 list_del(&fs_devices->list);
98                 free_fs_devices(fs_devices);
99         }
100         return 0;
101 }
102
103 static noinline struct btrfs_device *__find_device(struct list_head *head,
104                                                    u64 devid, u8 *uuid)
105 {
106         struct btrfs_device *dev;
107
108         list_for_each_entry(dev, head, dev_list) {
109                 if (dev->devid == devid &&
110                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
111                         return dev;
112                 }
113         }
114         return NULL;
115 }
116
117 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
118 {
119         struct btrfs_fs_devices *fs_devices;
120
121         list_for_each_entry(fs_devices, &fs_uuids, list) {
122                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
123                         return fs_devices;
124         }
125         return NULL;
126 }
127
128 static void requeue_list(struct btrfs_pending_bios *pending_bios,
129                         struct bio *head, struct bio *tail)
130 {
131
132         struct bio *old_head;
133
134         old_head = pending_bios->head;
135         pending_bios->head = head;
136         if (pending_bios->tail)
137                 tail->bi_next = old_head;
138         else
139                 pending_bios->tail = tail;
140 }
141
142 /*
143  * we try to collect pending bios for a device so we don't get a large
144  * number of procs sending bios down to the same device.  This greatly
145  * improves the schedulers ability to collect and merge the bios.
146  *
147  * But, it also turns into a long list of bios to process and that is sure
148  * to eventually make the worker thread block.  The solution here is to
149  * make some progress and then put this work struct back at the end of
150  * the list if the block device is congested.  This way, multiple devices
151  * can make progress from a single worker thread.
152  */
153 static noinline int run_scheduled_bios(struct btrfs_device *device)
154 {
155         struct bio *pending;
156         struct backing_dev_info *bdi;
157         struct btrfs_fs_info *fs_info;
158         struct btrfs_pending_bios *pending_bios;
159         struct bio *tail;
160         struct bio *cur;
161         int again = 0;
162         unsigned long num_run;
163         unsigned long num_sync_run;
164         unsigned long batch_run = 0;
165         unsigned long limit;
166         unsigned long last_waited = 0;
167         int force_reg = 0;
168
169         bdi = blk_get_backing_dev_info(device->bdev);
170         fs_info = device->dev_root->fs_info;
171         limit = btrfs_async_submit_limit(fs_info);
172         limit = limit * 2 / 3;
173
174         /* we want to make sure that every time we switch from the sync
175          * list to the normal list, we unplug
176          */
177         num_sync_run = 0;
178
179 loop:
180         spin_lock(&device->io_lock);
181
182 loop_lock:
183         num_run = 0;
184
185         /* take all the bios off the list at once and process them
186          * later on (without the lock held).  But, remember the
187          * tail and other pointers so the bios can be properly reinserted
188          * into the list if we hit congestion
189          */
190         if (!force_reg && device->pending_sync_bios.head) {
191                 pending_bios = &device->pending_sync_bios;
192                 force_reg = 1;
193         } else {
194                 pending_bios = &device->pending_bios;
195                 force_reg = 0;
196         }
197
198         pending = pending_bios->head;
199         tail = pending_bios->tail;
200         WARN_ON(pending && !tail);
201
202         /*
203          * if pending was null this time around, no bios need processing
204          * at all and we can stop.  Otherwise it'll loop back up again
205          * and do an additional check so no bios are missed.
206          *
207          * device->running_pending is used to synchronize with the
208          * schedule_bio code.
209          */
210         if (device->pending_sync_bios.head == NULL &&
211             device->pending_bios.head == NULL) {
212                 again = 0;
213                 device->running_pending = 0;
214         } else {
215                 again = 1;
216                 device->running_pending = 1;
217         }
218
219         pending_bios->head = NULL;
220         pending_bios->tail = NULL;
221
222         spin_unlock(&device->io_lock);
223
224         /*
225          * if we're doing the regular priority list, make sure we unplug
226          * for any high prio bios we've sent down
227          */
228         if (pending_bios == &device->pending_bios && num_sync_run > 0) {
229                 num_sync_run = 0;
230                 blk_run_backing_dev(bdi, NULL);
231         }
232
233         while (pending) {
234
235                 rmb();
236                 /* we want to work on both lists, but do more bios on the
237                  * sync list than the regular list
238                  */
239                 if ((num_run > 32 &&
240                     pending_bios != &device->pending_sync_bios &&
241                     device->pending_sync_bios.head) ||
242                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
243                     device->pending_bios.head)) {
244                         spin_lock(&device->io_lock);
245                         requeue_list(pending_bios, pending, tail);
246                         goto loop_lock;
247                 }
248
249                 cur = pending;
250                 pending = pending->bi_next;
251                 cur->bi_next = NULL;
252                 atomic_dec(&fs_info->nr_async_bios);
253
254                 if (atomic_read(&fs_info->nr_async_bios) < limit &&
255                     waitqueue_active(&fs_info->async_submit_wait))
256                         wake_up(&fs_info->async_submit_wait);
257
258                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
259                 submit_bio(cur->bi_rw, cur);
260                 num_run++;
261                 batch_run++;
262
263                 if (bio_sync(cur))
264                         num_sync_run++;
265
266                 if (need_resched()) {
267                         if (num_sync_run) {
268                                 blk_run_backing_dev(bdi, NULL);
269                                 num_sync_run = 0;
270                         }
271                         cond_resched();
272                 }
273
274                 /*
275                  * we made progress, there is more work to do and the bdi
276                  * is now congested.  Back off and let other work structs
277                  * run instead
278                  */
279                 if (pending && bdi_write_congested(bdi) && batch_run > 32 &&
280                     fs_info->fs_devices->open_devices > 1) {
281                         struct io_context *ioc;
282
283                         ioc = current->io_context;
284
285                         /*
286                          * the main goal here is that we don't want to
287                          * block if we're going to be able to submit
288                          * more requests without blocking.
289                          *
290                          * This code does two great things, it pokes into
291                          * the elevator code from a filesystem _and_
292                          * it makes assumptions about how batching works.
293                          */
294                         if (ioc && ioc->nr_batch_requests > 0 &&
295                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
296                             (last_waited == 0 ||
297                              ioc->last_waited == last_waited)) {
298                                 /*
299                                  * we want to go through our batch of
300                                  * requests and stop.  So, we copy out
301                                  * the ioc->last_waited time and test
302                                  * against it before looping
303                                  */
304                                 last_waited = ioc->last_waited;
305                                 if (need_resched()) {
306                                         if (num_sync_run) {
307                                                 blk_run_backing_dev(bdi, NULL);
308                                                 num_sync_run = 0;
309                                         }
310                                         cond_resched();
311                                 }
312                                 continue;
313                         }
314                         spin_lock(&device->io_lock);
315                         requeue_list(pending_bios, pending, tail);
316                         device->running_pending = 1;
317
318                         spin_unlock(&device->io_lock);
319                         btrfs_requeue_work(&device->work);
320                         goto done;
321                 }
322         }
323
324         if (num_sync_run) {
325                 num_sync_run = 0;
326                 blk_run_backing_dev(bdi, NULL);
327         }
328
329         cond_resched();
330         if (again)
331                 goto loop;
332
333         spin_lock(&device->io_lock);
334         if (device->pending_bios.head || device->pending_sync_bios.head)
335                 goto loop_lock;
336         spin_unlock(&device->io_lock);
337
338         /*
339          * IO has already been through a long path to get here.  Checksumming,
340          * async helper threads, perhaps compression.  We've done a pretty
341          * good job of collecting a batch of IO and should just unplug
342          * the device right away.
343          *
344          * This will help anyone who is waiting on the IO, they might have
345          * already unplugged, but managed to do so before the bio they
346          * cared about found its way down here.
347          */
348         blk_run_backing_dev(bdi, NULL);
349 done:
350         return 0;
351 }
352
353 static void pending_bios_fn(struct btrfs_work *work)
354 {
355         struct btrfs_device *device;
356
357         device = container_of(work, struct btrfs_device, work);
358         run_scheduled_bios(device);
359 }
360
361 static noinline int device_list_add(const char *path,
362                            struct btrfs_super_block *disk_super,
363                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
364 {
365         struct btrfs_device *device;
366         struct btrfs_fs_devices *fs_devices;
367         u64 found_transid = btrfs_super_generation(disk_super);
368
369         fs_devices = find_fsid(disk_super->fsid);
370         if (!fs_devices) {
371                 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
372                 if (!fs_devices)
373                         return -ENOMEM;
374                 INIT_LIST_HEAD(&fs_devices->devices);
375                 INIT_LIST_HEAD(&fs_devices->alloc_list);
376                 list_add(&fs_devices->list, &fs_uuids);
377                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
378                 fs_devices->latest_devid = devid;
379                 fs_devices->latest_trans = found_transid;
380                 mutex_init(&fs_devices->device_list_mutex);
381                 device = NULL;
382         } else {
383                 device = __find_device(&fs_devices->devices, devid,
384                                        disk_super->dev_item.uuid);
385         }
386         if (!device) {
387                 if (fs_devices->opened)
388                         return -EBUSY;
389
390                 device = kzalloc(sizeof(*device), GFP_NOFS);
391                 if (!device) {
392                         /* we can safely leave the fs_devices entry around */
393                         return -ENOMEM;
394                 }
395                 device->devid = devid;
396                 device->work.func = pending_bios_fn;
397                 memcpy(device->uuid, disk_super->dev_item.uuid,
398                        BTRFS_UUID_SIZE);
399                 device->barriers = 1;
400                 spin_lock_init(&device->io_lock);
401                 device->name = kstrdup(path, GFP_NOFS);
402                 if (!device->name) {
403                         kfree(device);
404                         return -ENOMEM;
405                 }
406                 INIT_LIST_HEAD(&device->dev_alloc_list);
407
408                 mutex_lock(&fs_devices->device_list_mutex);
409                 list_add(&device->dev_list, &fs_devices->devices);
410                 mutex_unlock(&fs_devices->device_list_mutex);
411
412                 device->fs_devices = fs_devices;
413                 fs_devices->num_devices++;
414         }
415
416         if (found_transid > fs_devices->latest_trans) {
417                 fs_devices->latest_devid = devid;
418                 fs_devices->latest_trans = found_transid;
419         }
420         *fs_devices_ret = fs_devices;
421         return 0;
422 }
423
424 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
425 {
426         struct btrfs_fs_devices *fs_devices;
427         struct btrfs_device *device;
428         struct btrfs_device *orig_dev;
429
430         fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
431         if (!fs_devices)
432                 return ERR_PTR(-ENOMEM);
433
434         INIT_LIST_HEAD(&fs_devices->devices);
435         INIT_LIST_HEAD(&fs_devices->alloc_list);
436         INIT_LIST_HEAD(&fs_devices->list);
437         mutex_init(&fs_devices->device_list_mutex);
438         fs_devices->latest_devid = orig->latest_devid;
439         fs_devices->latest_trans = orig->latest_trans;
440         memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));
441
442         mutex_lock(&orig->device_list_mutex);
443         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
444                 device = kzalloc(sizeof(*device), GFP_NOFS);
445                 if (!device)
446                         goto error;
447
448                 device->name = kstrdup(orig_dev->name, GFP_NOFS);
449                 if (!device->name)
450                         goto error;
451
452                 device->devid = orig_dev->devid;
453                 device->work.func = pending_bios_fn;
454                 memcpy(device->uuid, orig_dev->uuid, sizeof(device->uuid));
455                 device->barriers = 1;
456                 spin_lock_init(&device->io_lock);
457                 INIT_LIST_HEAD(&device->dev_list);
458                 INIT_LIST_HEAD(&device->dev_alloc_list);
459
460                 list_add(&device->dev_list, &fs_devices->devices);
461                 device->fs_devices = fs_devices;
462                 fs_devices->num_devices++;
463         }
464         mutex_unlock(&orig->device_list_mutex);
465         return fs_devices;
466 error:
467         mutex_unlock(&orig->device_list_mutex);
468         free_fs_devices(fs_devices);
469         return ERR_PTR(-ENOMEM);
470 }
471
472 int btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices)
473 {
474         struct btrfs_device *device, *next;
475
476         mutex_lock(&uuid_mutex);
477 again:
478         mutex_lock(&fs_devices->device_list_mutex);
479         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
480                 if (device->in_fs_metadata)
481                         continue;
482
483                 if (device->bdev) {
484                         close_bdev_exclusive(device->bdev, device->mode);
485                         device->bdev = NULL;
486                         fs_devices->open_devices--;
487                 }
488                 if (device->writeable) {
489                         list_del_init(&device->dev_alloc_list);
490                         device->writeable = 0;
491                         fs_devices->rw_devices--;
492                 }
493                 list_del_init(&device->dev_list);
494                 fs_devices->num_devices--;
495                 kfree(device->name);
496                 kfree(device);
497         }
498         mutex_unlock(&fs_devices->device_list_mutex);
499
500         if (fs_devices->seed) {
501                 fs_devices = fs_devices->seed;
502                 goto again;
503         }
504
505         mutex_unlock(&uuid_mutex);
506         return 0;
507 }
508
509 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
510 {
511         struct btrfs_device *device;
512
513         if (--fs_devices->opened > 0)
514                 return 0;
515
516         list_for_each_entry(device, &fs_devices->devices, dev_list) {
517                 if (device->bdev) {
518                         close_bdev_exclusive(device->bdev, device->mode);
519                         fs_devices->open_devices--;
520                 }
521                 if (device->writeable) {
522                         list_del_init(&device->dev_alloc_list);
523                         fs_devices->rw_devices--;
524                 }
525
526                 device->bdev = NULL;
527                 device->writeable = 0;
528                 device->in_fs_metadata = 0;
529         }
530         WARN_ON(fs_devices->open_devices);
531         WARN_ON(fs_devices->rw_devices);
532         fs_devices->opened = 0;
533         fs_devices->seeding = 0;
534
535         return 0;
536 }
537
538 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
539 {
540         struct btrfs_fs_devices *seed_devices = NULL;
541         int ret;
542
543         mutex_lock(&uuid_mutex);
544         ret = __btrfs_close_devices(fs_devices);
545         if (!fs_devices->opened) {
546                 seed_devices = fs_devices->seed;
547                 fs_devices->seed = NULL;
548         }
549         mutex_unlock(&uuid_mutex);
550
551         while (seed_devices) {
552                 fs_devices = seed_devices;
553                 seed_devices = fs_devices->seed;
554                 __btrfs_close_devices(fs_devices);
555                 free_fs_devices(fs_devices);
556         }
557         return ret;
558 }
559
560 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
561                                 fmode_t flags, void *holder)
562 {
563         struct block_device *bdev;
564         struct list_head *head = &fs_devices->devices;
565         struct btrfs_device *device;
566         struct block_device *latest_bdev = NULL;
567         struct buffer_head *bh;
568         struct btrfs_super_block *disk_super;
569         u64 latest_devid = 0;
570         u64 latest_transid = 0;
571         u64 devid;
572         int seeding = 1;
573         int ret = 0;
574
575         list_for_each_entry(device, head, dev_list) {
576                 if (device->bdev)
577                         continue;
578                 if (!device->name)
579                         continue;
580
581                 bdev = open_bdev_exclusive(device->name, flags, holder);
582                 if (IS_ERR(bdev)) {
583                         printk(KERN_INFO "open %s failed\n", device->name);
584                         goto error;
585                 }
586                 set_blocksize(bdev, 4096);
587
588                 bh = btrfs_read_dev_super(bdev);
589                 if (!bh)
590                         goto error_close;
591
592                 disk_super = (struct btrfs_super_block *)bh->b_data;
593                 devid = le64_to_cpu(disk_super->dev_item.devid);
594                 if (devid != device->devid)
595                         goto error_brelse;
596
597                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
598                            BTRFS_UUID_SIZE))
599                         goto error_brelse;
600
601                 device->generation = btrfs_super_generation(disk_super);
602                 if (!latest_transid || device->generation > latest_transid) {
603                         latest_devid = devid;
604                         latest_transid = device->generation;
605                         latest_bdev = bdev;
606                 }
607
608                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
609                         device->writeable = 0;
610                 } else {
611                         device->writeable = !bdev_read_only(bdev);
612                         seeding = 0;
613                 }
614
615                 device->bdev = bdev;
616                 device->in_fs_metadata = 0;
617                 device->mode = flags;
618
619                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
620                         fs_devices->rotating = 1;
621
622                 fs_devices->open_devices++;
623                 if (device->writeable) {
624                         fs_devices->rw_devices++;
625                         list_add(&device->dev_alloc_list,
626                                  &fs_devices->alloc_list);
627                 }
628                 continue;
629
630 error_brelse:
631                 brelse(bh);
632 error_close:
633                 close_bdev_exclusive(bdev, FMODE_READ);
634 error:
635                 continue;
636         }
637         if (fs_devices->open_devices == 0) {
638                 ret = -EIO;
639                 goto out;
640         }
641         fs_devices->seeding = seeding;
642         fs_devices->opened = 1;
643         fs_devices->latest_bdev = latest_bdev;
644         fs_devices->latest_devid = latest_devid;
645         fs_devices->latest_trans = latest_transid;
646         fs_devices->total_rw_bytes = 0;
647 out:
648         return ret;
649 }
650
651 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
652                        fmode_t flags, void *holder)
653 {
654         int ret;
655
656         mutex_lock(&uuid_mutex);
657         if (fs_devices->opened) {
658                 fs_devices->opened++;
659                 ret = 0;
660         } else {
661                 ret = __btrfs_open_devices(fs_devices, flags, holder);
662         }
663         mutex_unlock(&uuid_mutex);
664         return ret;
665 }
666
667 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
668                           struct btrfs_fs_devices **fs_devices_ret)
669 {
670         struct btrfs_super_block *disk_super;
671         struct block_device *bdev;
672         struct buffer_head *bh;
673         int ret;
674         u64 devid;
675         u64 transid;
676
677         mutex_lock(&uuid_mutex);
678
679         bdev = open_bdev_exclusive(path, flags, holder);
680
681         if (IS_ERR(bdev)) {
682                 ret = PTR_ERR(bdev);
683                 goto error;
684         }
685
686         ret = set_blocksize(bdev, 4096);
687         if (ret)
688                 goto error_close;
689         bh = btrfs_read_dev_super(bdev);
690         if (!bh) {
691                 ret = -EIO;
692                 goto error_close;
693         }
694         disk_super = (struct btrfs_super_block *)bh->b_data;
695         devid = le64_to_cpu(disk_super->dev_item.devid);
696         transid = btrfs_super_generation(disk_super);
697         if (disk_super->label[0])
698                 printk(KERN_INFO "device label %s ", disk_super->label);
699         else {
700                 /* FIXME, make a readl uuid parser */
701                 printk(KERN_INFO "device fsid %llx-%llx ",
702                        *(unsigned long long *)disk_super->fsid,
703                        *(unsigned long long *)(disk_super->fsid + 8));
704         }
705         printk(KERN_CONT "devid %llu transid %llu %s\n",
706                (unsigned long long)devid, (unsigned long long)transid, path);
707         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
708
709         brelse(bh);
710 error_close:
711         close_bdev_exclusive(bdev, flags);
712 error:
713         mutex_unlock(&uuid_mutex);
714         return ret;
715 }
716
717 /*
718  * this uses a pretty simple search, the expectation is that it is
719  * called very infrequently and that a given device has a small number
720  * of extents
721  */
722 static noinline int find_free_dev_extent(struct btrfs_trans_handle *trans,
723                                          struct btrfs_device *device,
724                                          u64 num_bytes, u64 *start)
725 {
726         struct btrfs_key key;
727         struct btrfs_root *root = device->dev_root;
728         struct btrfs_dev_extent *dev_extent = NULL;
729         struct btrfs_path *path;
730         u64 hole_size = 0;
731         u64 last_byte = 0;
732         u64 search_start = 0;
733         u64 search_end = device->total_bytes;
734         int ret;
735         int slot = 0;
736         int start_found;
737         struct extent_buffer *l;
738
739         path = btrfs_alloc_path();
740         if (!path)
741                 return -ENOMEM;
742         path->reada = 2;
743         start_found = 0;
744
745         /* FIXME use last free of some kind */
746
747         /* we don't want to overwrite the superblock on the drive,
748          * so we make sure to start at an offset of at least 1MB
749          */
750         search_start = max((u64)1024 * 1024, search_start);
751
752         if (root->fs_info->alloc_start + num_bytes <= device->total_bytes)
753                 search_start = max(root->fs_info->alloc_start, search_start);
754
755         key.objectid = device->devid;
756         key.offset = search_start;
757         key.type = BTRFS_DEV_EXTENT_KEY;
758         ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
759         if (ret < 0)
760                 goto error;
761         ret = btrfs_previous_item(root, path, 0, key.type);
762         if (ret < 0)
763                 goto error;
764         l = path->nodes[0];
765         btrfs_item_key_to_cpu(l, &key, path->slots[0]);
766         while (1) {
767                 l = path->nodes[0];
768                 slot = path->slots[0];
769                 if (slot >= btrfs_header_nritems(l)) {
770                         ret = btrfs_next_leaf(root, path);
771                         if (ret == 0)
772                                 continue;
773                         if (ret < 0)
774                                 goto error;
775 no_more_items:
776                         if (!start_found) {
777                                 if (search_start >= search_end) {
778                                         ret = -ENOSPC;
779                                         goto error;
780                                 }
781                                 *start = search_start;
782                                 start_found = 1;
783                                 goto check_pending;
784                         }
785                         *start = last_byte > search_start ?
786                                 last_byte : search_start;
787                         if (search_end <= *start) {
788                                 ret = -ENOSPC;
789                                 goto error;
790                         }
791                         goto check_pending;
792                 }
793                 btrfs_item_key_to_cpu(l, &key, slot);
794
795                 if (key.objectid < device->devid)
796                         goto next;
797
798                 if (key.objectid > device->devid)
799                         goto no_more_items;
800
801                 if (key.offset >= search_start && key.offset > last_byte &&
802                     start_found) {
803                         if (last_byte < search_start)
804                                 last_byte = search_start;
805                         hole_size = key.offset - last_byte;
806                         if (key.offset > last_byte &&
807                             hole_size >= num_bytes) {
808                                 *start = last_byte;
809                                 goto check_pending;
810                         }
811                 }
812                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
813                         goto next;
814
815                 start_found = 1;
816                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
817                 last_byte = key.offset + btrfs_dev_extent_length(l, dev_extent);
818 next:
819                 path->slots[0]++;
820                 cond_resched();
821         }
822 check_pending:
823         /* we have to make sure we didn't find an extent that has already
824          * been allocated by the map tree or the original allocation
825          */
826         BUG_ON(*start < search_start);
827
828         if (*start + num_bytes > search_end) {
829                 ret = -ENOSPC;
830                 goto error;
831         }
832         /* check for pending inserts here */
833         ret = 0;
834
835 error:
836         btrfs_free_path(path);
837         return ret;
838 }
839
840 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
841                           struct btrfs_device *device,
842                           u64 start)
843 {
844         int ret;
845         struct btrfs_path *path;
846         struct btrfs_root *root = device->dev_root;
847         struct btrfs_key key;
848         struct btrfs_key found_key;
849         struct extent_buffer *leaf = NULL;
850         struct btrfs_dev_extent *extent = NULL;
851
852         path = btrfs_alloc_path();
853         if (!path)
854                 return -ENOMEM;
855
856         key.objectid = device->devid;
857         key.offset = start;
858         key.type = BTRFS_DEV_EXTENT_KEY;
859
860         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
861         if (ret > 0) {
862                 ret = btrfs_previous_item(root, path, key.objectid,
863                                           BTRFS_DEV_EXTENT_KEY);
864                 BUG_ON(ret);
865                 leaf = path->nodes[0];
866                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
867                 extent = btrfs_item_ptr(leaf, path->slots[0],
868                                         struct btrfs_dev_extent);
869                 BUG_ON(found_key.offset > start || found_key.offset +
870                        btrfs_dev_extent_length(leaf, extent) < start);
871                 ret = 0;
872         } else if (ret == 0) {
873                 leaf = path->nodes[0];
874                 extent = btrfs_item_ptr(leaf, path->slots[0],
875                                         struct btrfs_dev_extent);
876         }
877         BUG_ON(ret);
878
879         if (device->bytes_used > 0)
880                 device->bytes_used -= btrfs_dev_extent_length(leaf, extent);
881         ret = btrfs_del_item(trans, root, path);
882         BUG_ON(ret);
883
884         btrfs_free_path(path);
885         return ret;
886 }
887
888 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
889                            struct btrfs_device *device,
890                            u64 chunk_tree, u64 chunk_objectid,
891                            u64 chunk_offset, u64 start, u64 num_bytes)
892 {
893         int ret;
894         struct btrfs_path *path;
895         struct btrfs_root *root = device->dev_root;
896         struct btrfs_dev_extent *extent;
897         struct extent_buffer *leaf;
898         struct btrfs_key key;
899
900         WARN_ON(!device->in_fs_metadata);
901         path = btrfs_alloc_path();
902         if (!path)
903                 return -ENOMEM;
904
905         key.objectid = device->devid;
906         key.offset = start;
907         key.type = BTRFS_DEV_EXTENT_KEY;
908         ret = btrfs_insert_empty_item(trans, root, path, &key,
909                                       sizeof(*extent));
910         BUG_ON(ret);
911
912         leaf = path->nodes[0];
913         extent = btrfs_item_ptr(leaf, path->slots[0],
914                                 struct btrfs_dev_extent);
915         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
916         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
917         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
918
919         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
920                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
921                     BTRFS_UUID_SIZE);
922
923         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
924         btrfs_mark_buffer_dirty(leaf);
925         btrfs_free_path(path);
926         return ret;
927 }
928
929 static noinline int find_next_chunk(struct btrfs_root *root,
930                                     u64 objectid, u64 *offset)
931 {
932         struct btrfs_path *path;
933         int ret;
934         struct btrfs_key key;
935         struct btrfs_chunk *chunk;
936         struct btrfs_key found_key;
937
938         path = btrfs_alloc_path();
939         BUG_ON(!path);
940
941         key.objectid = objectid;
942         key.offset = (u64)-1;
943         key.type = BTRFS_CHUNK_ITEM_KEY;
944
945         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
946         if (ret < 0)
947                 goto error;
948
949         BUG_ON(ret == 0);
950
951         ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
952         if (ret) {
953                 *offset = 0;
954         } else {
955                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
956                                       path->slots[0]);
957                 if (found_key.objectid != objectid)
958                         *offset = 0;
959                 else {
960                         chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
961                                                struct btrfs_chunk);
962                         *offset = found_key.offset +
963                                 btrfs_chunk_length(path->nodes[0], chunk);
964                 }
965         }
966         ret = 0;
967 error:
968         btrfs_free_path(path);
969         return ret;
970 }
971
972 static noinline int find_next_devid(struct btrfs_root *root, u64 *objectid)
973 {
974         int ret;
975         struct btrfs_key key;
976         struct btrfs_key found_key;
977         struct btrfs_path *path;
978
979         root = root->fs_info->chunk_root;
980
981         path = btrfs_alloc_path();
982         if (!path)
983                 return -ENOMEM;
984
985         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
986         key.type = BTRFS_DEV_ITEM_KEY;
987         key.offset = (u64)-1;
988
989         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
990         if (ret < 0)
991                 goto error;
992
993         BUG_ON(ret == 0);
994
995         ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
996                                   BTRFS_DEV_ITEM_KEY);
997         if (ret) {
998                 *objectid = 1;
999         } else {
1000                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1001                                       path->slots[0]);
1002                 *objectid = found_key.offset + 1;
1003         }
1004         ret = 0;
1005 error:
1006         btrfs_free_path(path);
1007         return ret;
1008 }
1009
1010 /*
1011  * the device information is stored in the chunk root
1012  * the btrfs_device struct should be fully filled in
1013  */
1014 int btrfs_add_device(struct btrfs_trans_handle *trans,
1015                      struct btrfs_root *root,
1016                      struct btrfs_device *device)
1017 {
1018         int ret;
1019         struct btrfs_path *path;
1020         struct btrfs_dev_item *dev_item;
1021         struct extent_buffer *leaf;
1022         struct btrfs_key key;
1023         unsigned long ptr;
1024
1025         root = root->fs_info->chunk_root;
1026
1027         path = btrfs_alloc_path();
1028         if (!path)
1029                 return -ENOMEM;
1030
1031         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1032         key.type = BTRFS_DEV_ITEM_KEY;
1033         key.offset = device->devid;
1034
1035         ret = btrfs_insert_empty_item(trans, root, path, &key,
1036                                       sizeof(*dev_item));
1037         if (ret)
1038                 goto out;
1039
1040         leaf = path->nodes[0];
1041         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1042
1043         btrfs_set_device_id(leaf, dev_item, device->devid);
1044         btrfs_set_device_generation(leaf, dev_item, 0);
1045         btrfs_set_device_type(leaf, dev_item, device->type);
1046         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1047         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1048         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1049         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
1050         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1051         btrfs_set_device_group(leaf, dev_item, 0);
1052         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1053         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1054         btrfs_set_device_start_offset(leaf, dev_item, 0);
1055
1056         ptr = (unsigned long)btrfs_device_uuid(dev_item);
1057         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1058         ptr = (unsigned long)btrfs_device_fsid(dev_item);
1059         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1060         btrfs_mark_buffer_dirty(leaf);
1061
1062         ret = 0;
1063 out:
1064         btrfs_free_path(path);
1065         return ret;
1066 }
1067
1068 static int btrfs_rm_dev_item(struct btrfs_root *root,
1069                              struct btrfs_device *device)
1070 {
1071         int ret;
1072         struct btrfs_path *path;
1073         struct btrfs_key key;
1074         struct btrfs_trans_handle *trans;
1075
1076         root = root->fs_info->chunk_root;
1077
1078         path = btrfs_alloc_path();
1079         if (!path)
1080                 return -ENOMEM;
1081
1082         trans = btrfs_start_transaction(root, 1);
1083         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1084         key.type = BTRFS_DEV_ITEM_KEY;
1085         key.offset = device->devid;
1086         lock_chunks(root);
1087
1088         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1089         if (ret < 0)
1090                 goto out;
1091
1092         if (ret > 0) {
1093                 ret = -ENOENT;
1094                 goto out;
1095         }
1096
1097         ret = btrfs_del_item(trans, root, path);
1098         if (ret)
1099                 goto out;
1100 out:
1101         btrfs_free_path(path);
1102         unlock_chunks(root);
1103         btrfs_commit_transaction(trans, root);
1104         return ret;
1105 }
1106
1107 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1108 {
1109         struct btrfs_device *device;
1110         struct btrfs_device *next_device;
1111         struct block_device *bdev;
1112         struct buffer_head *bh = NULL;
1113         struct btrfs_super_block *disk_super;
1114         u64 all_avail;
1115         u64 devid;
1116         u64 num_devices;
1117         u8 *dev_uuid;
1118         int ret = 0;
1119
1120         mutex_lock(&uuid_mutex);
1121         mutex_lock(&root->fs_info->volume_mutex);
1122
1123         all_avail = root->fs_info->avail_data_alloc_bits |
1124                 root->fs_info->avail_system_alloc_bits |
1125                 root->fs_info->avail_metadata_alloc_bits;
1126
1127         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) &&
1128             root->fs_info->fs_devices->rw_devices <= 4) {
1129                 printk(KERN_ERR "btrfs: unable to go below four devices "
1130                        "on raid10\n");
1131                 ret = -EINVAL;
1132                 goto out;
1133         }
1134
1135         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) &&
1136             root->fs_info->fs_devices->rw_devices <= 2) {
1137                 printk(KERN_ERR "btrfs: unable to go below two "
1138                        "devices on raid1\n");
1139                 ret = -EINVAL;
1140                 goto out;
1141         }
1142
1143         if (strcmp(device_path, "missing") == 0) {
1144                 struct list_head *devices;
1145                 struct btrfs_device *tmp;
1146
1147                 device = NULL;
1148                 devices = &root->fs_info->fs_devices->devices;
1149                 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1150                 list_for_each_entry(tmp, devices, dev_list) {
1151                         if (tmp->in_fs_metadata && !tmp->bdev) {
1152                                 device = tmp;
1153                                 break;
1154                         }
1155                 }
1156                 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1157                 bdev = NULL;
1158                 bh = NULL;
1159                 disk_super = NULL;
1160                 if (!device) {
1161                         printk(KERN_ERR "btrfs: no missing devices found to "
1162                                "remove\n");
1163                         goto out;
1164                 }
1165         } else {
1166                 bdev = open_bdev_exclusive(device_path, FMODE_READ,
1167                                       root->fs_info->bdev_holder);
1168                 if (IS_ERR(bdev)) {
1169                         ret = PTR_ERR(bdev);
1170                         goto out;
1171                 }
1172
1173                 set_blocksize(bdev, 4096);
1174                 bh = btrfs_read_dev_super(bdev);
1175                 if (!bh) {
1176                         ret = -EIO;
1177                         goto error_close;
1178                 }
1179                 disk_super = (struct btrfs_super_block *)bh->b_data;
1180                 devid = le64_to_cpu(disk_super->dev_item.devid);
1181                 dev_uuid = disk_super->dev_item.uuid;
1182                 device = btrfs_find_device(root, devid, dev_uuid,
1183                                            disk_super->fsid);
1184                 if (!device) {
1185                         ret = -ENOENT;
1186                         goto error_brelse;
1187                 }
1188         }
1189
1190         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1191                 printk(KERN_ERR "btrfs: unable to remove the only writeable "
1192                        "device\n");
1193                 ret = -EINVAL;
1194                 goto error_brelse;
1195         }
1196
1197         if (device->writeable) {
1198                 list_del_init(&device->dev_alloc_list);
1199                 root->fs_info->fs_devices->rw_devices--;
1200         }
1201
1202         ret = btrfs_shrink_device(device, 0);
1203         if (ret)
1204                 goto error_brelse;
1205
1206         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1207         if (ret)
1208                 goto error_brelse;
1209
1210         device->in_fs_metadata = 0;
1211
1212         /*
1213          * the device list mutex makes sure that we don't change
1214          * the device list while someone else is writing out all
1215          * the device supers.
1216          */
1217         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1218         list_del_init(&device->dev_list);
1219         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1220
1221         device->fs_devices->num_devices--;
1222
1223         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1224                                  struct btrfs_device, dev_list);
1225         if (device->bdev == root->fs_info->sb->s_bdev)
1226                 root->fs_info->sb->s_bdev = next_device->bdev;
1227         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1228                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1229
1230         if (device->bdev) {
1231                 close_bdev_exclusive(device->bdev, device->mode);
1232                 device->bdev = NULL;
1233                 device->fs_devices->open_devices--;
1234         }
1235
1236         num_devices = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
1237         btrfs_set_super_num_devices(&root->fs_info->super_copy, num_devices);
1238
1239         if (device->fs_devices->open_devices == 0) {
1240                 struct btrfs_fs_devices *fs_devices;
1241                 fs_devices = root->fs_info->fs_devices;
1242                 while (fs_devices) {
1243                         if (fs_devices->seed == device->fs_devices)
1244                                 break;
1245                         fs_devices = fs_devices->seed;
1246                 }
1247                 fs_devices->seed = device->fs_devices->seed;
1248                 device->fs_devices->seed = NULL;
1249                 __btrfs_close_devices(device->fs_devices);
1250                 free_fs_devices(device->fs_devices);
1251         }
1252
1253         /*
1254          * at this point, the device is zero sized.  We want to
1255          * remove it from the devices list and zero out the old super
1256          */
1257         if (device->writeable) {
1258                 /* make sure this device isn't detected as part of
1259                  * the FS anymore
1260                  */
1261                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1262                 set_buffer_dirty(bh);
1263                 sync_dirty_buffer(bh);
1264         }
1265
1266         kfree(device->name);
1267         kfree(device);
1268         ret = 0;
1269
1270 error_brelse:
1271         brelse(bh);
1272 error_close:
1273         if (bdev)
1274                 close_bdev_exclusive(bdev, FMODE_READ);
1275 out:
1276         mutex_unlock(&root->fs_info->volume_mutex);
1277         mutex_unlock(&uuid_mutex);
1278         return ret;
1279 }
1280
1281 /*
1282  * does all the dirty work required for changing file system's UUID.
1283  */
1284 static int btrfs_prepare_sprout(struct btrfs_trans_handle *trans,
1285                                 struct btrfs_root *root)
1286 {
1287         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
1288         struct btrfs_fs_devices *old_devices;
1289         struct btrfs_fs_devices *seed_devices;
1290         struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
1291         struct btrfs_device *device;
1292         u64 super_flags;
1293
1294         BUG_ON(!mutex_is_locked(&uuid_mutex));
1295         if (!fs_devices->seeding)
1296                 return -EINVAL;
1297
1298         seed_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
1299         if (!seed_devices)
1300                 return -ENOMEM;
1301
1302         old_devices = clone_fs_devices(fs_devices);
1303         if (IS_ERR(old_devices)) {
1304                 kfree(seed_devices);
1305                 return PTR_ERR(old_devices);
1306         }
1307
1308         list_add(&old_devices->list, &fs_uuids);
1309
1310         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
1311         seed_devices->opened = 1;
1312         INIT_LIST_HEAD(&seed_devices->devices);
1313         INIT_LIST_HEAD(&seed_devices->alloc_list);
1314         mutex_init(&seed_devices->device_list_mutex);
1315         list_splice_init(&fs_devices->devices, &seed_devices->devices);
1316         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
1317         list_for_each_entry(device, &seed_devices->devices, dev_list) {
1318                 device->fs_devices = seed_devices;
1319         }
1320
1321         fs_devices->seeding = 0;
1322         fs_devices->num_devices = 0;
1323         fs_devices->open_devices = 0;
1324         fs_devices->seed = seed_devices;
1325
1326         generate_random_uuid(fs_devices->fsid);
1327         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1328         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1329         super_flags = btrfs_super_flags(disk_super) &
1330                       ~BTRFS_SUPER_FLAG_SEEDING;
1331         btrfs_set_super_flags(disk_super, super_flags);
1332
1333         return 0;
1334 }
1335
1336 /*
1337  * strore the expected generation for seed devices in device items.
1338  */
1339 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
1340                                struct btrfs_root *root)
1341 {
1342         struct btrfs_path *path;
1343         struct extent_buffer *leaf;
1344         struct btrfs_dev_item *dev_item;
1345         struct btrfs_device *device;
1346         struct btrfs_key key;
1347         u8 fs_uuid[BTRFS_UUID_SIZE];
1348         u8 dev_uuid[BTRFS_UUID_SIZE];
1349         u64 devid;
1350         int ret;
1351
1352         path = btrfs_alloc_path();
1353         if (!path)
1354                 return -ENOMEM;
1355
1356         root = root->fs_info->chunk_root;
1357         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1358         key.offset = 0;
1359         key.type = BTRFS_DEV_ITEM_KEY;
1360
1361         while (1) {
1362                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1363                 if (ret < 0)
1364                         goto error;
1365
1366                 leaf = path->nodes[0];
1367 next_slot:
1368                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1369                         ret = btrfs_next_leaf(root, path);
1370                         if (ret > 0)
1371                                 break;
1372                         if (ret < 0)
1373                                 goto error;
1374                         leaf = path->nodes[0];
1375                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1376                         btrfs_release_path(root, path);
1377                         continue;
1378                 }
1379
1380                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1381                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
1382                     key.type != BTRFS_DEV_ITEM_KEY)
1383                         break;
1384
1385                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
1386                                           struct btrfs_dev_item);
1387                 devid = btrfs_device_id(leaf, dev_item);
1388                 read_extent_buffer(leaf, dev_uuid,
1389                                    (unsigned long)btrfs_device_uuid(dev_item),
1390                                    BTRFS_UUID_SIZE);
1391                 read_extent_buffer(leaf, fs_uuid,
1392                                    (unsigned long)btrfs_device_fsid(dev_item),
1393                                    BTRFS_UUID_SIZE);
1394                 device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
1395                 BUG_ON(!device);
1396
1397                 if (device->fs_devices->seeding) {
1398                         btrfs_set_device_generation(leaf, dev_item,
1399                                                     device->generation);
1400                         btrfs_mark_buffer_dirty(leaf);
1401                 }
1402
1403                 path->slots[0]++;
1404                 goto next_slot;
1405         }
1406         ret = 0;
1407 error:
1408         btrfs_free_path(path);
1409         return ret;
1410 }
1411
1412 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
1413 {
1414         struct btrfs_trans_handle *trans;
1415         struct btrfs_device *device;
1416         struct block_device *bdev;
1417         struct list_head *devices;
1418         struct super_block *sb = root->fs_info->sb;
1419         u64 total_bytes;
1420         int seeding_dev = 0;
1421         int ret = 0;
1422
1423         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
1424                 return -EINVAL;
1425
1426         bdev = open_bdev_exclusive(device_path, 0, root->fs_info->bdev_holder);
1427         if (!bdev)
1428                 return -EIO;
1429
1430         if (root->fs_info->fs_devices->seeding) {
1431                 seeding_dev = 1;
1432                 down_write(&sb->s_umount);
1433                 mutex_lock(&uuid_mutex);
1434         }
1435
1436         filemap_write_and_wait(bdev->bd_inode->i_mapping);
1437         mutex_lock(&root->fs_info->volume_mutex);
1438
1439         devices = &root->fs_info->fs_devices->devices;
1440         /*
1441          * we have the volume lock, so we don't need the extra
1442          * device list mutex while reading the list here.
1443          */
1444         list_for_each_entry(device, devices, dev_list) {
1445                 if (device->bdev == bdev) {
1446                         ret = -EEXIST;
1447                         goto error;
1448                 }
1449         }
1450
1451         device = kzalloc(sizeof(*device), GFP_NOFS);
1452         if (!device) {
1453                 /* we can safely leave the fs_devices entry around */
1454                 ret = -ENOMEM;
1455                 goto error;
1456         }
1457
1458         device->name = kstrdup(device_path, GFP_NOFS);
1459         if (!device->name) {
1460                 kfree(device);
1461                 ret = -ENOMEM;
1462                 goto error;
1463         }
1464
1465         ret = find_next_devid(root, &device->devid);
1466         if (ret) {
1467                 kfree(device);
1468                 goto error;
1469         }
1470
1471         trans = btrfs_start_transaction(root, 1);
1472         lock_chunks(root);
1473
1474         device->barriers = 1;
1475         device->writeable = 1;
1476         device->work.func = pending_bios_fn;
1477         generate_random_uuid(device->uuid);
1478         spin_lock_init(&device->io_lock);
1479         device->generation = trans->transid;
1480         device->io_width = root->sectorsize;
1481         device->io_align = root->sectorsize;
1482         device->sector_size = root->sectorsize;
1483         device->total_bytes = i_size_read(bdev->bd_inode);
1484         device->disk_total_bytes = device->total_bytes;
1485         device->dev_root = root->fs_info->dev_root;
1486         device->bdev = bdev;
1487         device->in_fs_metadata = 1;
1488         device->mode = 0;
1489         set_blocksize(device->bdev, 4096);
1490
1491         if (seeding_dev) {
1492                 sb->s_flags &= ~MS_RDONLY;
1493                 ret = btrfs_prepare_sprout(trans, root);
1494                 BUG_ON(ret);
1495         }
1496
1497         device->fs_devices = root->fs_info->fs_devices;
1498
1499         /*
1500          * we don't want write_supers to jump in here with our device
1501          * half setup
1502          */
1503         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1504         list_add(&device->dev_list, &root->fs_info->fs_devices->devices);
1505         list_add(&device->dev_alloc_list,
1506                  &root->fs_info->fs_devices->alloc_list);
1507         root->fs_info->fs_devices->num_devices++;
1508         root->fs_info->fs_devices->open_devices++;
1509         root->fs_info->fs_devices->rw_devices++;
1510         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
1511
1512         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
1513                 root->fs_info->fs_devices->rotating = 1;
1514
1515         total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
1516         btrfs_set_super_total_bytes(&root->fs_info->super_copy,
1517                                     total_bytes + device->total_bytes);
1518
1519         total_bytes = btrfs_super_num_devices(&root->fs_info->super_copy);
1520         btrfs_set_super_num_devices(&root->fs_info->super_copy,
1521                                     total_bytes + 1);
1522         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1523
1524         if (seeding_dev) {
1525                 ret = init_first_rw_device(trans, root, device);
1526                 BUG_ON(ret);
1527                 ret = btrfs_finish_sprout(trans, root);
1528                 BUG_ON(ret);
1529         } else {
1530                 ret = btrfs_add_device(trans, root, device);
1531         }
1532
1533         /*
1534          * we've got more storage, clear any full flags on the space
1535          * infos
1536          */
1537         btrfs_clear_space_info_full(root->fs_info);
1538
1539         unlock_chunks(root);
1540         btrfs_commit_transaction(trans, root);
1541
1542         if (seeding_dev) {
1543                 mutex_unlock(&uuid_mutex);
1544                 up_write(&sb->s_umount);
1545
1546                 ret = btrfs_relocate_sys_chunks(root);
1547                 BUG_ON(ret);
1548         }
1549 out:
1550         mutex_unlock(&root->fs_info->volume_mutex);
1551         return ret;
1552 error:
1553         close_bdev_exclusive(bdev, 0);
1554         if (seeding_dev) {
1555                 mutex_unlock(&uuid_mutex);
1556                 up_write(&sb->s_umount);
1557         }
1558         goto out;
1559 }
1560
1561 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
1562                                         struct btrfs_device *device)
1563 {
1564         int ret;
1565         struct btrfs_path *path;
1566         struct btrfs_root *root;
1567         struct btrfs_dev_item *dev_item;
1568         struct extent_buffer *leaf;
1569         struct btrfs_key key;
1570
1571         root = device->dev_root->fs_info->chunk_root;
1572
1573         path = btrfs_alloc_path();
1574         if (!path)
1575                 return -ENOMEM;
1576
1577         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1578         key.type = BTRFS_DEV_ITEM_KEY;
1579         key.offset = device->devid;
1580
1581         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1582         if (ret < 0)
1583                 goto out;
1584
1585         if (ret > 0) {
1586                 ret = -ENOENT;
1587                 goto out;
1588         }
1589
1590         leaf = path->nodes[0];
1591         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1592
1593         btrfs_set_device_id(leaf, dev_item, device->devid);
1594         btrfs_set_device_type(leaf, dev_item, device->type);
1595         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1596         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1597         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1598         btrfs_set_device_total_bytes(leaf, dev_item, device->disk_total_bytes);
1599         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1600         btrfs_mark_buffer_dirty(leaf);
1601
1602 out:
1603         btrfs_free_path(path);
1604         return ret;
1605 }
1606
1607 static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
1608                       struct btrfs_device *device, u64 new_size)
1609 {
1610         struct btrfs_super_block *super_copy =
1611                 &device->dev_root->fs_info->super_copy;
1612         u64 old_total = btrfs_super_total_bytes(super_copy);
1613         u64 diff = new_size - device->total_bytes;
1614
1615         if (!device->writeable)
1616                 return -EACCES;
1617         if (new_size <= device->total_bytes)
1618                 return -EINVAL;
1619
1620         btrfs_set_super_total_bytes(super_copy, old_total + diff);
1621         device->fs_devices->total_rw_bytes += diff;
1622
1623         device->total_bytes = new_size;
1624         btrfs_clear_space_info_full(device->dev_root->fs_info);
1625
1626         return btrfs_update_device(trans, device);
1627 }
1628
1629 int btrfs_grow_device(struct btrfs_trans_handle *trans,
1630                       struct btrfs_device *device, u64 new_size)
1631 {
1632         int ret;
1633         lock_chunks(device->dev_root);
1634         ret = __btrfs_grow_device(trans, device, new_size);
1635         unlock_chunks(device->dev_root);
1636         return ret;
1637 }
1638
1639 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
1640                             struct btrfs_root *root,
1641                             u64 chunk_tree, u64 chunk_objectid,
1642                             u64 chunk_offset)
1643 {
1644         int ret;
1645         struct btrfs_path *path;
1646         struct btrfs_key key;
1647
1648         root = root->fs_info->chunk_root;
1649         path = btrfs_alloc_path();
1650         if (!path)
1651                 return -ENOMEM;
1652
1653         key.objectid = chunk_objectid;
1654         key.offset = chunk_offset;
1655         key.type = BTRFS_CHUNK_ITEM_KEY;
1656
1657         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1658         BUG_ON(ret);
1659
1660         ret = btrfs_del_item(trans, root, path);
1661         BUG_ON(ret);
1662
1663         btrfs_free_path(path);
1664         return 0;
1665 }
1666
1667 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
1668                         chunk_offset)
1669 {
1670         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
1671         struct btrfs_disk_key *disk_key;
1672         struct btrfs_chunk *chunk;
1673         u8 *ptr;
1674         int ret = 0;
1675         u32 num_stripes;
1676         u32 array_size;
1677         u32 len = 0;
1678         u32 cur;
1679         struct btrfs_key key;
1680
1681         array_size = btrfs_super_sys_array_size(super_copy);
1682
1683         ptr = super_copy->sys_chunk_array;
1684         cur = 0;
1685
1686         while (cur < array_size) {
1687                 disk_key = (struct btrfs_disk_key *)ptr;
1688                 btrfs_disk_key_to_cpu(&key, disk_key);
1689
1690                 len = sizeof(*disk_key);
1691
1692                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
1693                         chunk = (struct btrfs_chunk *)(ptr + len);
1694                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
1695                         len += btrfs_chunk_item_size(num_stripes);
1696                 } else {
1697                         ret = -EIO;
1698                         break;
1699                 }
1700                 if (key.objectid == chunk_objectid &&
1701                     key.offset == chunk_offset) {
1702                         memmove(ptr, ptr + len, array_size - (cur + len));
1703                         array_size -= len;
1704                         btrfs_set_super_sys_array_size(super_copy, array_size);
1705                 } else {
1706                         ptr += len;
1707                         cur += len;
1708                 }
1709         }
1710         return ret;
1711 }
1712
1713 static int btrfs_relocate_chunk(struct btrfs_root *root,
1714                          u64 chunk_tree, u64 chunk_objectid,
1715                          u64 chunk_offset)
1716 {
1717         struct extent_map_tree *em_tree;
1718         struct btrfs_root *extent_root;
1719         struct btrfs_trans_handle *trans;
1720         struct extent_map *em;
1721         struct map_lookup *map;
1722         int ret;
1723         int i;
1724
1725         root = root->fs_info->chunk_root;
1726         extent_root = root->fs_info->extent_root;
1727         em_tree = &root->fs_info->mapping_tree.map_tree;
1728
1729         /* step one, relocate all the extents inside this chunk */
1730         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
1731         BUG_ON(ret);
1732
1733         trans = btrfs_start_transaction(root, 1);
1734         BUG_ON(!trans);
1735
1736         lock_chunks(root);
1737
1738         /*
1739          * step two, delete the device extents and the
1740          * chunk tree entries
1741          */
1742         spin_lock(&em_tree->lock);
1743         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
1744         spin_unlock(&em_tree->lock);
1745
1746         BUG_ON(em->start > chunk_offset ||
1747                em->start + em->len < chunk_offset);
1748         map = (struct map_lookup *)em->bdev;
1749
1750         for (i = 0; i < map->num_stripes; i++) {
1751                 ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
1752                                             map->stripes[i].physical);
1753                 BUG_ON(ret);
1754
1755                 if (map->stripes[i].dev) {
1756                         ret = btrfs_update_device(trans, map->stripes[i].dev);
1757                         BUG_ON(ret);
1758                 }
1759         }
1760         ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
1761                                chunk_offset);
1762
1763         BUG_ON(ret);
1764
1765         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
1766                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
1767                 BUG_ON(ret);
1768         }
1769
1770         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
1771         BUG_ON(ret);
1772
1773         spin_lock(&em_tree->lock);
1774         remove_extent_mapping(em_tree, em);
1775         spin_unlock(&em_tree->lock);
1776
1777         kfree(map);
1778         em->bdev = NULL;
1779
1780         /* once for the tree */
1781         free_extent_map(em);
1782         /* once for us */
1783         free_extent_map(em);
1784
1785         unlock_chunks(root);
1786         btrfs_end_transaction(trans, root);
1787         return 0;
1788 }
1789
1790 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
1791 {
1792         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
1793         struct btrfs_path *path;
1794         struct extent_buffer *leaf;
1795         struct btrfs_chunk *chunk;
1796         struct btrfs_key key;
1797         struct btrfs_key found_key;
1798         u64 chunk_tree = chunk_root->root_key.objectid;
1799         u64 chunk_type;
1800         int ret;
1801
1802         path = btrfs_alloc_path();
1803         if (!path)
1804                 return -ENOMEM;
1805
1806         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
1807         key.offset = (u64)-1;
1808         key.type = BTRFS_CHUNK_ITEM_KEY;
1809
1810         while (1) {
1811                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
1812                 if (ret < 0)
1813                         goto error;
1814                 BUG_ON(ret == 0);
1815
1816                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
1817                                           key.type);
1818                 if (ret < 0)
1819                         goto error;
1820                 if (ret > 0)
1821                         break;
1822
1823                 leaf = path->nodes[0];
1824                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1825
1826                 chunk = btrfs_item_ptr(leaf, path->slots[0],
1827                                        struct btrfs_chunk);
1828                 chunk_type = btrfs_chunk_type(leaf, chunk);
1829                 btrfs_release_path(chunk_root, path);
1830
1831                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
1832                         ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
1833                                                    found_key.objectid,
1834                                                    found_key.offset);
1835                         BUG_ON(ret);
1836                 }
1837
1838                 if (found_key.offset == 0)
1839                         break;
1840                 key.offset = found_key.offset - 1;
1841         }
1842         ret = 0;
1843 error:
1844         btrfs_free_path(path);
1845         return ret;
1846 }
1847
1848 static u64 div_factor(u64 num, int factor)
1849 {
1850         if (factor == 10)
1851                 return num;
1852         num *= factor;
1853         do_div(num, 10);
1854         return num;
1855 }
1856
1857 int btrfs_balance(struct btrfs_root *dev_root)
1858 {
1859         int ret;
1860         struct list_head *devices = &dev_root->fs_info->fs_devices->devices;
1861         struct btrfs_device *device;
1862         u64 old_size;
1863         u64 size_to_free;
1864         struct btrfs_path *path;
1865         struct btrfs_key key;
1866         struct btrfs_chunk *chunk;
1867         struct btrfs_root *chunk_root = dev_root->fs_info->chunk_root;
1868         struct btrfs_trans_handle *trans;
1869         struct btrfs_key found_key;
1870
1871         if (dev_root->fs_info->sb->s_flags & MS_RDONLY)
1872                 return -EROFS;
1873
1874         mutex_lock(&dev_root->fs_info->volume_mutex);
1875         dev_root = dev_root->fs_info->dev_root;
1876
1877         /* step one make some room on all the devices */
1878         list_for_each_entry(device, devices, dev_list) {
1879                 old_size = device->total_bytes;
1880                 size_to_free = div_factor(old_size, 1);
1881                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
1882                 if (!device->writeable ||
1883                     device->total_bytes - device->bytes_used > size_to_free)
1884                         continue;
1885
1886                 ret = btrfs_shrink_device(device, old_size - size_to_free);
1887                 BUG_ON(ret);
1888
1889                 trans = btrfs_start_transaction(dev_root, 1);
1890                 BUG_ON(!trans);
1891
1892                 ret = btrfs_grow_device(trans, device, old_size);
1893                 BUG_ON(ret);
1894
1895                 btrfs_end_transaction(trans, dev_root);
1896         }
1897
1898         /* step two, relocate all the chunks */
1899         path = btrfs_alloc_path();
1900         BUG_ON(!path);
1901
1902         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
1903         key.offset = (u64)-1;
1904         key.type = BTRFS_CHUNK_ITEM_KEY;
1905
1906         while (1) {
1907                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
1908                 if (ret < 0)
1909                         goto error;
1910
1911                 /*
1912                  * this shouldn't happen, it means the last relocate
1913                  * failed
1914                  */
1915                 if (ret == 0)
1916                         break;
1917
1918                 ret = btrfs_previous_item(chunk_root, path, 0,
1919                                           BTRFS_CHUNK_ITEM_KEY);
1920                 if (ret)
1921                         break;
1922
1923                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1924                                       path->slots[0]);
1925                 if (found_key.objectid != key.objectid)
1926                         break;
1927
1928                 chunk = btrfs_item_ptr(path->nodes[0],
1929                                        path->slots[0],
1930                                        struct btrfs_chunk);
1931                 key.offset = found_key.offset;
1932                 /* chunk zero is special */
1933                 if (key.offset == 0)
1934                         break;
1935
1936                 btrfs_release_path(chunk_root, path);
1937                 ret = btrfs_relocate_chunk(chunk_root,
1938                                            chunk_root->root_key.objectid,
1939                                            found_key.objectid,
1940                                            found_key.offset);
1941                 BUG_ON(ret);
1942         }
1943         ret = 0;
1944 error:
1945         btrfs_free_path(path);
1946         mutex_unlock(&dev_root->fs_info->volume_mutex);
1947         return ret;
1948 }
1949
1950 /*
1951  * shrinking a device means finding all of the device extents past
1952  * the new size, and then following the back refs to the chunks.
1953  * The chunk relocation code actually frees the device extent
1954  */
1955 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
1956 {
1957         struct btrfs_trans_handle *trans;
1958         struct btrfs_root *root = device->dev_root;
1959         struct btrfs_dev_extent *dev_extent = NULL;
1960         struct btrfs_path *path;
1961         u64 length;
1962         u64 chunk_tree;
1963         u64 chunk_objectid;
1964         u64 chunk_offset;
1965         int ret;
1966         int slot;
1967         struct extent_buffer *l;
1968         struct btrfs_key key;
1969         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
1970         u64 old_total = btrfs_super_total_bytes(super_copy);
1971         u64 diff = device->total_bytes - new_size;
1972
1973         if (new_size >= device->total_bytes)
1974                 return -EINVAL;
1975
1976         path = btrfs_alloc_path();
1977         if (!path)
1978                 return -ENOMEM;
1979
1980         trans = btrfs_start_transaction(root, 1);
1981         if (!trans) {
1982                 ret = -ENOMEM;
1983                 goto done;
1984         }
1985
1986         path->reada = 2;
1987
1988         lock_chunks(root);
1989
1990         device->total_bytes = new_size;
1991         if (device->writeable)
1992                 device->fs_devices->total_rw_bytes -= diff;
1993         unlock_chunks(root);
1994         btrfs_end_transaction(trans, root);
1995
1996         key.objectid = device->devid;
1997         key.offset = (u64)-1;
1998         key.type = BTRFS_DEV_EXTENT_KEY;
1999
2000         while (1) {
2001                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2002                 if (ret < 0)
2003                         goto done;
2004
2005                 ret = btrfs_previous_item(root, path, 0, key.type);
2006                 if (ret < 0)
2007                         goto done;
2008                 if (ret) {
2009                         ret = 0;
2010                         break;
2011                 }
2012
2013                 l = path->nodes[0];
2014                 slot = path->slots[0];
2015                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
2016
2017                 if (key.objectid != device->devid)
2018                         break;
2019
2020                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
2021                 length = btrfs_dev_extent_length(l, dev_extent);
2022
2023                 if (key.offset + length <= new_size)
2024                         break;
2025
2026                 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
2027                 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
2028                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
2029                 btrfs_release_path(root, path);
2030
2031                 ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
2032                                            chunk_offset);
2033                 if (ret)
2034                         goto done;
2035         }
2036
2037         /* Shrinking succeeded, else we would be at "done". */
2038         trans = btrfs_start_transaction(root, 1);
2039         if (!trans) {
2040                 ret = -ENOMEM;
2041                 goto done;
2042         }
2043         lock_chunks(root);
2044
2045         device->disk_total_bytes = new_size;
2046         /* Now btrfs_update_device() will change the on-disk size. */
2047         ret = btrfs_update_device(trans, device);
2048         if (ret) {
2049                 unlock_chunks(root);
2050                 btrfs_end_transaction(trans, root);
2051                 goto done;
2052         }
2053         WARN_ON(diff > old_total);
2054         btrfs_set_super_total_bytes(super_copy, old_total - diff);
2055         unlock_chunks(root);
2056         btrfs_end_transaction(trans, root);
2057 done:
2058         btrfs_free_path(path);
2059         return ret;
2060 }
2061
2062 static int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
2063                            struct btrfs_root *root,
2064                            struct btrfs_key *key,
2065                            struct btrfs_chunk *chunk, int item_size)
2066 {
2067         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
2068         struct btrfs_disk_key disk_key;
2069         u32 array_size;
2070         u8 *ptr;
2071
2072         array_size = btrfs_super_sys_array_size(super_copy);
2073         if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
2074                 return -EFBIG;
2075
2076         ptr = super_copy->sys_chunk_array + array_size;
2077         btrfs_cpu_key_to_disk(&disk_key, key);
2078         memcpy(ptr, &disk_key, sizeof(disk_key));
2079         ptr += sizeof(disk_key);
2080         memcpy(ptr, chunk, item_size);
2081         item_size += sizeof(disk_key);
2082         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
2083         return 0;
2084 }
2085
2086 static noinline u64 chunk_bytes_by_type(u64 type, u64 calc_size,
2087                                         int num_stripes, int sub_stripes)
2088 {
2089         if (type & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_DUP))
2090                 return calc_size;
2091         else if (type & BTRFS_BLOCK_GROUP_RAID10)
2092                 return calc_size * (num_stripes / sub_stripes);
2093         else
2094                 return calc_size * num_stripes;
2095 }
2096
2097 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
2098                                struct btrfs_root *extent_root,
2099                                struct map_lookup **map_ret,
2100                                u64 *num_bytes, u64 *stripe_size,
2101                                u64 start, u64 type)
2102 {
2103         struct btrfs_fs_info *info = extent_root->fs_info;
2104         struct btrfs_device *device = NULL;
2105         struct btrfs_fs_devices *fs_devices = info->fs_devices;
2106         struct list_head *cur;
2107         struct map_lookup *map = NULL;
2108         struct extent_map_tree *em_tree;
2109         struct extent_map *em;
2110         struct list_head private_devs;
2111         int min_stripe_size = 1 * 1024 * 1024;
2112         u64 calc_size = 1024 * 1024 * 1024;
2113         u64 max_chunk_size = calc_size;
2114         u64 min_free;
2115         u64 avail;
2116         u64 max_avail = 0;
2117         u64 dev_offset;
2118         int num_stripes = 1;
2119         int min_stripes = 1;
2120         int sub_stripes = 0;
2121         int looped = 0;
2122         int ret;
2123         int index;
2124         int stripe_len = 64 * 1024;
2125
2126         if ((type & BTRFS_BLOCK_GROUP_RAID1) &&
2127             (type & BTRFS_BLOCK_GROUP_DUP)) {
2128                 WARN_ON(1);
2129                 type &= ~BTRFS_BLOCK_GROUP_DUP;
2130         }
2131         if (list_empty(&fs_devices->alloc_list))
2132                 return -ENOSPC;
2133
2134         if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
2135                 num_stripes = fs_devices->rw_devices;
2136                 min_stripes = 2;
2137         }
2138         if (type & (BTRFS_BLOCK_GROUP_DUP)) {
2139                 num_stripes = 2;
2140                 min_stripes = 2;
2141         }
2142         if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
2143                 num_stripes = min_t(u64, 2, fs_devices->rw_devices);
2144                 if (num_stripes < 2)
2145                         return -ENOSPC;
2146                 min_stripes = 2;
2147         }
2148         if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
2149                 num_stripes = fs_devices->rw_devices;
2150                 if (num_stripes < 4)
2151                         return -ENOSPC;
2152                 num_stripes &= ~(u32)1;
2153                 sub_stripes = 2;
2154                 min_stripes = 4;
2155         }
2156
2157         if (type & BTRFS_BLOCK_GROUP_DATA) {
2158                 max_chunk_size = 10 * calc_size;
2159                 min_stripe_size = 64 * 1024 * 1024;
2160         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
2161                 max_chunk_size = 4 * calc_size;
2162                 min_stripe_size = 32 * 1024 * 1024;
2163         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
2164                 calc_size = 8 * 1024 * 1024;
2165                 max_chunk_size = calc_size * 2;
2166                 min_stripe_size = 1 * 1024 * 1024;
2167         }
2168
2169         /* we don't want a chunk larger than 10% of writeable space */
2170         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
2171                              max_chunk_size);
2172
2173 again:
2174         if (!map || map->num_stripes != num_stripes) {
2175                 kfree(map);
2176                 map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
2177                 if (!map)
2178                         return -ENOMEM;
2179                 map->num_stripes = num_stripes;
2180         }
2181
2182         if (calc_size * num_stripes > max_chunk_size) {
2183                 calc_size = max_chunk_size;
2184                 do_div(calc_size, num_stripes);
2185                 do_div(calc_size, stripe_len);
2186                 calc_size *= stripe_len;
2187         }
2188         /* we don't want tiny stripes */
2189         calc_size = max_t(u64, min_stripe_size, calc_size);
2190
2191         do_div(calc_size, stripe_len);
2192         calc_size *= stripe_len;
2193
2194         cur = fs_devices->alloc_list.next;
2195         index = 0;
2196
2197         if (type & BTRFS_BLOCK_GROUP_DUP)
2198                 min_free = calc_size * 2;
2199         else
2200                 min_free = calc_size;
2201
2202         /*
2203          * we add 1MB because we never use the first 1MB of the device, unless
2204          * we've looped, then we are likely allocating the maximum amount of
2205          * space left already
2206          */
2207         if (!looped)
2208                 min_free += 1024 * 1024;
2209
2210         INIT_LIST_HEAD(&private_devs);
2211         while (index < num_stripes) {
2212                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
2213                 BUG_ON(!device->writeable);
2214                 if (device->total_bytes > device->bytes_used)
2215                         avail = device->total_bytes - device->bytes_used;
2216                 else
2217                         avail = 0;
2218                 cur = cur->next;
2219
2220                 if (device->in_fs_metadata && avail >= min_free) {
2221                         ret = find_free_dev_extent(trans, device,
2222                                                    min_free, &dev_offset);
2223                         if (ret == 0) {
2224                                 list_move_tail(&device->dev_alloc_list,
2225                                                &private_devs);
2226                                 map->stripes[index].dev = device;
2227                                 map->stripes[index].physical = dev_offset;
2228                                 index++;
2229                                 if (type & BTRFS_BLOCK_GROUP_DUP) {
2230                                         map->stripes[index].dev = device;
2231                                         map->stripes[index].physical =
2232                                                 dev_offset + calc_size;
2233                                         index++;
2234                                 }
2235                         }
2236                 } else if (device->in_fs_metadata && avail > max_avail)
2237                         max_avail = avail;
2238                 if (cur == &fs_devices->alloc_list)
2239                         break;
2240         }
2241         list_splice(&private_devs, &fs_devices->alloc_list);
2242         if (index < num_stripes) {
2243                 if (index >= min_stripes) {
2244                         num_stripes = index;
2245                         if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
2246                                 num_stripes /= sub_stripes;
2247                                 num_stripes *= sub_stripes;
2248                         }
2249                         looped = 1;
2250                         goto again;
2251                 }
2252                 if (!looped && max_avail > 0) {
2253                         looped = 1;
2254                         calc_size = max_avail;
2255                         goto again;
2256                 }
2257                 kfree(map);
2258                 return -ENOSPC;
2259         }
2260         map->sector_size = extent_root->sectorsize;
2261         map->stripe_len = stripe_len;
2262         map->io_align = stripe_len;
2263         map->io_width = stripe_len;
2264         map->type = type;
2265         map->num_stripes = num_stripes;
2266         map->sub_stripes = sub_stripes;
2267
2268         *map_ret = map;
2269         *stripe_size = calc_size;
2270         *num_bytes = chunk_bytes_by_type(type, calc_size,
2271                                          num_stripes, sub_stripes);
2272
2273         em = alloc_extent_map(GFP_NOFS);
2274         if (!em) {
2275                 kfree(map);
2276                 return -ENOMEM;
2277         }
2278         em->bdev = (struct block_device *)map;
2279         em->start = start;
2280         em->len = *num_bytes;
2281         em->block_start = 0;
2282         em->block_len = em->len;
2283
2284         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
2285         spin_lock(&em_tree->lock);
2286         ret = add_extent_mapping(em_tree, em);
2287         spin_unlock(&em_tree->lock);
2288         BUG_ON(ret);
2289         free_extent_map(em);
2290
2291         ret = btrfs_make_block_group(trans, extent_root, 0, type,
2292                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2293                                      start, *num_bytes);
2294         BUG_ON(ret);
2295
2296         index = 0;
2297         while (index < map->num_stripes) {
2298                 device = map->stripes[index].dev;
2299                 dev_offset = map->stripes[index].physical;
2300
2301                 ret = btrfs_alloc_dev_extent(trans, device,
2302                                 info->chunk_root->root_key.objectid,
2303                                 BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2304                                 start, dev_offset, calc_size);
2305                 BUG_ON(ret);
2306                 index++;
2307         }
2308
2309         return 0;
2310 }
2311
2312 static int __finish_chunk_alloc(struct btrfs_trans_handle *trans,
2313                                 struct btrfs_root *extent_root,
2314                                 struct map_lookup *map, u64 chunk_offset,
2315                                 u64 chunk_size, u64 stripe_size)
2316 {
2317         u64 dev_offset;
2318         struct btrfs_key key;
2319         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
2320         struct btrfs_device *device;
2321         struct btrfs_chunk *chunk;
2322         struct btrfs_stripe *stripe;
2323         size_t item_size = btrfs_chunk_item_size(map->num_stripes);
2324         int index = 0;
2325         int ret;
2326
2327         chunk = kzalloc(item_size, GFP_NOFS);
2328         if (!chunk)
2329                 return -ENOMEM;
2330
2331         index = 0;
2332         while (index < map->num_stripes) {
2333                 device = map->stripes[index].dev;
2334                 device->bytes_used += stripe_size;
2335                 ret = btrfs_update_device(trans, device);
2336                 BUG_ON(ret);
2337                 index++;
2338         }
2339
2340         index = 0;
2341         stripe = &chunk->stripe;
2342         while (index < map->num_stripes) {
2343                 device = map->stripes[index].dev;
2344                 dev_offset = map->stripes[index].physical;
2345
2346                 btrfs_set_stack_stripe_devid(stripe, device->devid);
2347                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
2348                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
2349                 stripe++;
2350                 index++;
2351         }
2352
2353         btrfs_set_stack_chunk_length(chunk, chunk_size);
2354         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
2355         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
2356         btrfs_set_stack_chunk_type(chunk, map->type);
2357         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
2358         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
2359         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
2360         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
2361         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
2362
2363         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2364         key.type = BTRFS_CHUNK_ITEM_KEY;
2365         key.offset = chunk_offset;
2366
2367         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
2368         BUG_ON(ret);
2369
2370         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2371                 ret = btrfs_add_system_chunk(trans, chunk_root, &key, chunk,
2372                                              item_size);
2373                 BUG_ON(ret);
2374         }
2375         kfree(chunk);
2376         return 0;
2377 }
2378
2379 /*
2380  * Chunk allocation falls into two parts. The first part does works
2381  * that make the new allocated chunk useable, but not do any operation
2382  * that modifies the chunk tree. The second part does the works that
2383  * require modifying the chunk tree. This division is important for the
2384  * bootstrap process of adding storage to a seed btrfs.
2385  */
2386 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
2387                       struct btrfs_root *extent_root, u64 type)
2388 {
2389         u64 chunk_offset;
2390         u64 chunk_size;
2391         u64 stripe_size;
2392         struct map_lookup *map;
2393         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
2394         int ret;
2395
2396         ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2397                               &chunk_offset);
2398         if (ret)
2399                 return ret;
2400
2401         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
2402                                   &stripe_size, chunk_offset, type);
2403         if (ret)
2404                 return ret;
2405
2406         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
2407                                    chunk_size, stripe_size);
2408         BUG_ON(ret);
2409         return 0;
2410 }
2411
2412 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
2413                                          struct btrfs_root *root,
2414                                          struct btrfs_device *device)
2415 {
2416         u64 chunk_offset;
2417         u64 sys_chunk_offset;
2418         u64 chunk_size;
2419         u64 sys_chunk_size;
2420         u64 stripe_size;
2421         u64 sys_stripe_size;
2422         u64 alloc_profile;
2423         struct map_lookup *map;
2424         struct map_lookup *sys_map;
2425         struct btrfs_fs_info *fs_info = root->fs_info;
2426         struct btrfs_root *extent_root = fs_info->extent_root;
2427         int ret;
2428
2429         ret = find_next_chunk(fs_info->chunk_root,
2430                               BTRFS_FIRST_CHUNK_TREE_OBJECTID, &chunk_offset);
2431         BUG_ON(ret);
2432
2433         alloc_profile = BTRFS_BLOCK_GROUP_METADATA |
2434                         (fs_info->metadata_alloc_profile &
2435                          fs_info->avail_metadata_alloc_bits);
2436         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
2437
2438         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
2439                                   &stripe_size, chunk_offset, alloc_profile);
2440         BUG_ON(ret);
2441
2442         sys_chunk_offset = chunk_offset + chunk_size;
2443
2444         alloc_profile = BTRFS_BLOCK_GROUP_SYSTEM |
2445                         (fs_info->system_alloc_profile &
2446                          fs_info->avail_system_alloc_bits);
2447         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
2448
2449         ret = __btrfs_alloc_chunk(trans, extent_root, &sys_map,
2450                                   &sys_chunk_size, &sys_stripe_size,
2451                                   sys_chunk_offset, alloc_profile);
2452         BUG_ON(ret);
2453
2454         ret = btrfs_add_device(trans, fs_info->chunk_root, device);
2455         BUG_ON(ret);
2456
2457         /*
2458          * Modifying chunk tree needs allocating new blocks from both
2459          * system block group and metadata block group. So we only can
2460          * do operations require modifying the chunk tree after both
2461          * block groups were created.
2462          */
2463         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
2464                                    chunk_size, stripe_size);
2465         BUG_ON(ret);
2466
2467         ret = __finish_chunk_alloc(trans, extent_root, sys_map,
2468                                    sys_chunk_offset, sys_chunk_size,
2469                                    sys_stripe_size);
2470         BUG_ON(ret);
2471         return 0;
2472 }
2473
2474 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
2475 {
2476         struct extent_map *em;
2477         struct map_lookup *map;
2478         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
2479         int readonly = 0;
2480         int i;
2481
2482         spin_lock(&map_tree->map_tree.lock);
2483         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
2484         spin_unlock(&map_tree->map_tree.lock);
2485         if (!em)
2486                 return 1;
2487
2488         map = (struct map_lookup *)em->bdev;
2489         for (i = 0; i < map->num_stripes; i++) {
2490                 if (!map->stripes[i].dev->writeable) {
2491                         readonly = 1;
2492                         break;
2493                 }
2494         }
2495         free_extent_map(em);
2496         return readonly;
2497 }
2498
2499 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
2500 {
2501         extent_map_tree_init(&tree->map_tree, GFP_NOFS);
2502 }
2503
2504 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
2505 {
2506         struct extent_map *em;
2507
2508         while (1) {
2509                 spin_lock(&tree->map_tree.lock);
2510                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
2511                 if (em)
2512                         remove_extent_mapping(&tree->map_tree, em);
2513                 spin_unlock(&tree->map_tree.lock);
2514                 if (!em)
2515                         break;
2516                 kfree(em->bdev);
2517                 /* once for us */
2518                 free_extent_map(em);
2519                 /* once for the tree */
2520                 free_extent_map(em);
2521         }
2522 }
2523
2524 int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
2525 {
2526         struct extent_map *em;
2527         struct map_lookup *map;
2528         struct extent_map_tree *em_tree = &map_tree->map_tree;
2529         int ret;
2530
2531         spin_lock(&em_tree->lock);
2532         em = lookup_extent_mapping(em_tree, logical, len);
2533         spin_unlock(&em_tree->lock);
2534         BUG_ON(!em);
2535
2536         BUG_ON(em->start > logical || em->start + em->len < logical);
2537         map = (struct map_lookup *)em->bdev;
2538         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
2539                 ret = map->num_stripes;
2540         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
2541                 ret = map->sub_stripes;
2542         else
2543                 ret = 1;
2544         free_extent_map(em);
2545         return ret;
2546 }
2547
2548 static int find_live_mirror(struct map_lookup *map, int first, int num,
2549                             int optimal)
2550 {
2551         int i;
2552         if (map->stripes[optimal].dev->bdev)
2553                 return optimal;
2554         for (i = first; i < first + num; i++) {
2555                 if (map->stripes[i].dev->bdev)
2556                         return i;
2557         }
2558         /* we couldn't find one that doesn't fail.  Just return something
2559          * and the io error handling code will clean up eventually
2560          */
2561         return optimal;
2562 }
2563
2564 static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
2565                              u64 logical, u64 *length,
2566                              struct btrfs_multi_bio **multi_ret,
2567                              int mirror_num, struct page *unplug_page)
2568 {
2569         struct extent_map *em;
2570         struct map_lookup *map;
2571         struct extent_map_tree *em_tree = &map_tree->map_tree;
2572         u64 offset;
2573         u64 stripe_offset;
2574         u64 stripe_nr;
2575         int stripes_allocated = 8;
2576         int stripes_required = 1;
2577         int stripe_index;
2578         int i;
2579         int num_stripes;
2580         int max_errors = 0;
2581         struct btrfs_multi_bio *multi = NULL;
2582
2583         if (multi_ret && !(rw & (1 << BIO_RW)))
2584                 stripes_allocated = 1;
2585 again:
2586         if (multi_ret) {
2587                 multi = kzalloc(btrfs_multi_bio_size(stripes_allocated),
2588                                 GFP_NOFS);
2589                 if (!multi)
2590                         return -ENOMEM;
2591
2592                 atomic_set(&multi->error, 0);
2593         }
2594
2595         spin_lock(&em_tree->lock);
2596         em = lookup_extent_mapping(em_tree, logical, *length);
2597         spin_unlock(&em_tree->lock);
2598
2599         if (!em && unplug_page)
2600                 return 0;
2601
2602         if (!em) {
2603                 printk(KERN_CRIT "unable to find logical %llu len %llu\n",
2604                        (unsigned long long)logical,
2605                        (unsigned long long)*length);
2606                 BUG();
2607         }
2608
2609         BUG_ON(em->start > logical || em->start + em->len < logical);
2610         map = (struct map_lookup *)em->bdev;
2611         offset = logical - em->start;
2612
2613         if (mirror_num > map->num_stripes)
2614                 mirror_num = 0;
2615
2616         /* if our multi bio struct is too small, back off and try again */
2617         if (rw & (1 << BIO_RW)) {
2618                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
2619                                  BTRFS_BLOCK_GROUP_DUP)) {
2620                         stripes_required = map->num_stripes;
2621                         max_errors = 1;
2622                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
2623                         stripes_required = map->sub_stripes;
2624                         max_errors = 1;
2625                 }
2626         }
2627         if (multi_ret && (rw & (1 << BIO_RW)) &&
2628             stripes_allocated < stripes_required) {
2629                 stripes_allocated = map->num_stripes;
2630                 free_extent_map(em);
2631                 kfree(multi);
2632                 goto again;
2633         }
2634         stripe_nr = offset;
2635         /*
2636          * stripe_nr counts the total number of stripes we have to stride
2637          * to get to this block
2638          */
2639         do_div(stripe_nr, map->stripe_len);
2640
2641         stripe_offset = stripe_nr * map->stripe_len;
2642         BUG_ON(offset < stripe_offset);
2643
2644         /* stripe_offset is the offset of this block in its stripe*/
2645         stripe_offset = offset - stripe_offset;
2646
2647         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
2648                          BTRFS_BLOCK_GROUP_RAID10 |
2649                          BTRFS_BLOCK_GROUP_DUP)) {
2650                 /* we limit the length of each bio to what fits in a stripe */
2651                 *length = min_t(u64, em->len - offset,
2652                               map->stripe_len - stripe_offset);
2653         } else {
2654                 *length = em->len - offset;
2655         }
2656
2657         if (!multi_ret && !unplug_page)
2658                 goto out;
2659
2660         num_stripes = 1;
2661         stripe_index = 0;
2662         if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
2663                 if (unplug_page || (rw & (1 << BIO_RW)))
2664                         num_stripes = map->num_stripes;
2665                 else if (mirror_num)
2666                         stripe_index = mirror_num - 1;
2667                 else {
2668                         stripe_index = find_live_mirror(map, 0,
2669                                             map->num_stripes,
2670                                             current->pid % map->num_stripes);
2671                 }
2672
2673         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
2674                 if (rw & (1 << BIO_RW))
2675                         num_stripes = map->num_stripes;
2676                 else if (mirror_num)
2677                         stripe_index = mirror_num - 1;
2678
2679         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
2680                 int factor = map->num_stripes / map->sub_stripes;
2681
2682                 stripe_index = do_div(stripe_nr, factor);
2683                 stripe_index *= map->sub_stripes;
2684
2685                 if (unplug_page || (rw & (1 << BIO_RW)))
2686                         num_stripes = map->sub_stripes;
2687                 else if (mirror_num)
2688                         stripe_index += mirror_num - 1;
2689                 else {
2690                         stripe_index = find_live_mirror(map, stripe_index,
2691                                               map->sub_stripes, stripe_index +
2692                                               current->pid % map->sub_stripes);
2693                 }
2694         } else {
2695                 /*
2696                  * after this do_div call, stripe_nr is the number of stripes
2697                  * on this device we have to walk to find the data, and
2698                  * stripe_index is the number of our device in the stripe array
2699                  */
2700                 stripe_index = do_div(stripe_nr, map->num_stripes);
2701         }
2702         BUG_ON(stripe_index >= map->num_stripes);
2703
2704         for (i = 0; i < num_stripes; i++) {
2705                 if (unplug_page) {
2706                         struct btrfs_device *device;
2707                         struct backing_dev_info *bdi;
2708
2709                         device = map->stripes[stripe_index].dev;
2710                         if (device->bdev) {
2711                                 bdi = blk_get_backing_dev_info(device->bdev);
2712                                 if (bdi->unplug_io_fn)
2713                                         bdi->unplug_io_fn(bdi, unplug_page);
2714                         }
2715                 } else {
2716                         multi->stripes[i].physical =
2717                                 map->stripes[stripe_index].physical +
2718                                 stripe_offset + stripe_nr * map->stripe_len;
2719                         multi->stripes[i].dev = map->stripes[stripe_index].dev;
2720                 }
2721                 stripe_index++;
2722         }
2723         if (multi_ret) {
2724                 *multi_ret = multi;
2725                 multi->num_stripes = num_stripes;
2726                 multi->max_errors = max_errors;
2727         }
2728 out:
2729         free_extent_map(em);
2730         return 0;
2731 }
2732
2733 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
2734                       u64 logical, u64 *length,
2735                       struct btrfs_multi_bio **multi_ret, int mirror_num)
2736 {
2737         return __btrfs_map_block(map_tree, rw, logical, length, multi_ret,
2738                                  mirror_num, NULL);
2739 }
2740
2741 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
2742                      u64 chunk_start, u64 physical, u64 devid,
2743                      u64 **logical, int *naddrs, int *stripe_len)
2744 {
2745         struct extent_map_tree *em_tree = &map_tree->map_tree;
2746         struct extent_map *em;
2747         struct map_lookup *map;
2748         u64 *buf;
2749         u64 bytenr;
2750         u64 length;
2751         u64 stripe_nr;
2752         int i, j, nr = 0;
2753
2754         spin_lock(&em_tree->lock);
2755         em = lookup_extent_mapping(em_tree, chunk_start, 1);
2756         spin_unlock(&em_tree->lock);
2757
2758         BUG_ON(!em || em->start != chunk_start);
2759         map = (struct map_lookup *)em->bdev;
2760
2761         length = em->len;
2762         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
2763                 do_div(length, map->num_stripes / map->sub_stripes);
2764         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
2765                 do_div(length, map->num_stripes);
2766
2767         buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
2768         BUG_ON(!buf);
2769
2770         for (i = 0; i < map->num_stripes; i++) {
2771                 if (devid && map->stripes[i].dev->devid != devid)
2772                         continue;
2773                 if (map->stripes[i].physical > physical ||
2774                     map->stripes[i].physical + length <= physical)
2775                         continue;
2776
2777                 stripe_nr = physical - map->stripes[i].physical;
2778                 do_div(stripe_nr, map->stripe_len);
2779
2780                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
2781                         stripe_nr = stripe_nr * map->num_stripes + i;
2782                         do_div(stripe_nr, map->sub_stripes);
2783                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
2784                         stripe_nr = stripe_nr * map->num_stripes + i;
2785                 }
2786                 bytenr = chunk_start + stripe_nr * map->stripe_len;
2787                 WARN_ON(nr >= map->num_stripes);
2788                 for (j = 0; j < nr; j++) {
2789                         if (buf[j] == bytenr)
2790                                 break;
2791                 }
2792                 if (j == nr) {
2793                         WARN_ON(nr >= map->num_stripes);
2794                         buf[nr++] = bytenr;
2795                 }
2796         }
2797
2798         *logical = buf;
2799         *naddrs = nr;
2800         *stripe_len = map->stripe_len;
2801
2802         free_extent_map(em);
2803         return 0;
2804 }
2805
2806 int btrfs_unplug_page(struct btrfs_mapping_tree *map_tree,
2807                       u64 logical, struct page *page)
2808 {
2809         u64 length = PAGE_CACHE_SIZE;
2810         return __btrfs_map_block(map_tree, READ, logical, &length,
2811                                  NULL, 0, page);
2812 }
2813
2814 static void end_bio_multi_stripe(struct bio *bio, int err)
2815 {
2816         struct btrfs_multi_bio *multi = bio->bi_private;
2817         int is_orig_bio = 0;
2818
2819         if (err)
2820                 atomic_inc(&multi->error);
2821
2822         if (bio == multi->orig_bio)
2823                 is_orig_bio = 1;
2824
2825         if (atomic_dec_and_test(&multi->stripes_pending)) {
2826                 if (!is_orig_bio) {
2827                         bio_put(bio);
2828                         bio = multi->orig_bio;
2829                 }
2830                 bio->bi_private = multi->private;
2831                 bio->bi_end_io = multi->end_io;
2832                 /* only send an error to the higher layers if it is
2833                  * beyond the tolerance of the multi-bio
2834                  */
2835                 if (atomic_read(&multi->error) > multi->max_errors) {
2836                         err = -EIO;
2837                 } else if (err) {
2838                         /*
2839                          * this bio is actually up to date, we didn't
2840                          * go over the max number of errors
2841                          */
2842                         set_bit(BIO_UPTODATE, &bio->bi_flags);
2843                         err = 0;
2844                 }
2845                 kfree(multi);
2846
2847                 bio_endio(bio, err);
2848         } else if (!is_orig_bio) {
2849                 bio_put(bio);
2850         }
2851 }
2852
2853 struct async_sched {
2854         struct bio *bio;
2855         int rw;
2856         struct btrfs_fs_info *info;
2857         struct btrfs_work work;
2858 };
2859
2860 /*
2861  * see run_scheduled_bios for a description of why bios are collected for
2862  * async submit.
2863  *
2864  * This will add one bio to the pending list for a device and make sure
2865  * the work struct is scheduled.
2866  */
2867 static noinline int schedule_bio(struct btrfs_root *root,
2868                                  struct btrfs_device *device,
2869                                  int rw, struct bio *bio)
2870 {
2871         int should_queue = 1;
2872         struct btrfs_pending_bios *pending_bios;
2873
2874         /* don't bother with additional async steps for reads, right now */
2875         if (!(rw & (1 << BIO_RW))) {
2876                 bio_get(bio);
2877                 submit_bio(rw, bio);
2878                 bio_put(bio);
2879                 return 0;
2880         }
2881
2882         /*
2883          * nr_async_bios allows us to reliably return congestion to the
2884          * higher layers.  Otherwise, the async bio makes it appear we have
2885          * made progress against dirty pages when we've really just put it
2886          * on a queue for later
2887          */
2888         atomic_inc(&root->fs_info->nr_async_bios);
2889         WARN_ON(bio->bi_next);
2890         bio->bi_next = NULL;
2891         bio->bi_rw |= rw;
2892
2893         spin_lock(&device->io_lock);
2894         if (bio_sync(bio))
2895                 pending_bios = &device->pending_sync_bios;
2896         else
2897                 pending_bios = &device->pending_bios;
2898
2899         if (pending_bios->tail)
2900                 pending_bios->tail->bi_next = bio;
2901
2902         pending_bios->tail = bio;
2903         if (!pending_bios->head)
2904                 pending_bios->head = bio;
2905         if (device->running_pending)
2906                 should_queue = 0;
2907
2908         spin_unlock(&device->io_lock);
2909
2910         if (should_queue)
2911                 btrfs_queue_worker(&root->fs_info->submit_workers,
2912                                    &device->work);
2913         return 0;
2914 }
2915
2916 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
2917                   int mirror_num, int async_submit)
2918 {
2919         struct btrfs_mapping_tree *map_tree;
2920         struct btrfs_device *dev;
2921         struct bio *first_bio = bio;
2922         u64 logical = (u64)bio->bi_sector << 9;
2923         u64 length = 0;
2924         u64 map_length;
2925         struct btrfs_multi_bio *multi = NULL;
2926         int ret;
2927         int dev_nr = 0;
2928         int total_devs = 1;
2929
2930         length = bio->bi_size;
2931         map_tree = &root->fs_info->mapping_tree;
2932         map_length = length;
2933
2934         ret = btrfs_map_block(map_tree, rw, logical, &map_length, &multi,
2935                               mirror_num);
2936         BUG_ON(ret);
2937
2938         total_devs = multi->num_stripes;
2939         if (map_length < length) {
2940                 printk(KERN_CRIT "mapping failed logical %llu bio len %llu "
2941                        "len %llu\n", (unsigned long long)logical,
2942                        (unsigned long long)length,
2943                        (unsigned long long)map_length);
2944                 BUG();
2945         }
2946         multi->end_io = first_bio->bi_end_io;
2947         multi->private = first_bio->bi_private;
2948         multi->orig_bio = first_bio;
2949         atomic_set(&multi->stripes_pending, multi->num_stripes);
2950
2951         while (dev_nr < total_devs) {
2952                 if (total_devs > 1) {
2953                         if (dev_nr < total_devs - 1) {
2954                                 bio = bio_clone(first_bio, GFP_NOFS);
2955                                 BUG_ON(!bio);
2956                         } else {
2957                                 bio = first_bio;
2958                         }
2959                         bio->bi_private = multi;
2960                         bio->bi_end_io = end_bio_multi_stripe;
2961                 }
2962                 bio->bi_sector = multi->stripes[dev_nr].physical >> 9;
2963                 dev = multi->stripes[dev_nr].dev;
2964                 BUG_ON(rw == WRITE && !dev->writeable);
2965                 if (dev && dev->bdev) {
2966                         bio->bi_bdev = dev->bdev;
2967                         if (async_submit)
2968                                 schedule_bio(root, dev, rw, bio);
2969                         else
2970                                 submit_bio(rw, bio);
2971                 } else {
2972                         bio->bi_bdev = root->fs_info->fs_devices->latest_bdev;
2973                         bio->bi_sector = logical >> 9;
2974                         bio_endio(bio, -EIO);
2975                 }
2976                 dev_nr++;
2977         }
2978         if (total_devs == 1)
2979                 kfree(multi);
2980         return 0;
2981 }
2982
2983 struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
2984                                        u8 *uuid, u8 *fsid)
2985 {
2986         struct btrfs_device *device;
2987         struct btrfs_fs_devices *cur_devices;
2988
2989         cur_devices = root->fs_info->fs_devices;
2990         while (cur_devices) {
2991                 if (!fsid ||
2992                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
2993                         device = __find_device(&cur_devices->devices,
2994                                                devid, uuid);
2995                         if (device)
2996                                 return device;
2997                 }
2998                 cur_devices = cur_devices->seed;
2999         }
3000         return NULL;
3001 }
3002
3003 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
3004                                             u64 devid, u8 *dev_uuid)
3005 {
3006         struct btrfs_device *device;
3007         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
3008
3009         device = kzalloc(sizeof(*device), GFP_NOFS);
3010         if (!device)
3011                 return NULL;
3012         list_add(&device->dev_list,
3013                  &fs_devices->devices);
3014         device->barriers = 1;
3015         device->dev_root = root->fs_info->dev_root;
3016         device->devid = devid;
3017         device->work.func = pending_bios_fn;
3018         device->fs_devices = fs_devices;
3019         fs_devices->num_devices++;
3020         spin_lock_init(&device->io_lock);
3021         INIT_LIST_HEAD(&device->dev_alloc_list);
3022         memcpy(device->uuid, dev_uuid, BTRFS_UUID_SIZE);
3023         return device;
3024 }
3025
3026 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
3027                           struct extent_buffer *leaf,
3028                           struct btrfs_chunk *chunk)
3029 {
3030         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
3031         struct map_lookup *map;
3032         struct extent_map *em;
3033         u64 logical;
3034         u64 length;
3035         u64 devid;
3036         u8 uuid[BTRFS_UUID_SIZE];
3037         int num_stripes;
3038         int ret;
3039         int i;
3040
3041         logical = key->offset;
3042         length = btrfs_chunk_length(leaf, chunk);
3043
3044         spin_lock(&map_tree->map_tree.lock);
3045         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
3046         spin_unlock(&map_tree->map_tree.lock);
3047
3048         /* already mapped? */
3049         if (em && em->start <= logical && em->start + em->len > logical) {
3050                 free_extent_map(em);
3051                 return 0;
3052         } else if (em) {
3053                 free_extent_map(em);
3054         }
3055
3056         em = alloc_extent_map(GFP_NOFS);
3057         if (!em)
3058                 return -ENOMEM;
3059         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3060         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
3061         if (!map) {
3062                 free_extent_map(em);
3063                 return -ENOMEM;
3064         }
3065
3066         em->bdev = (struct block_device *)map;
3067         em->start = logical;
3068         em->len = length;
3069         em->block_start = 0;
3070         em->block_len = em->len;
3071
3072         map->num_stripes = num_stripes;
3073         map->io_width = btrfs_chunk_io_width(leaf, chunk);
3074         map->io_align = btrfs_chunk_io_align(leaf, chunk);
3075         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
3076         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
3077         map->type = btrfs_chunk_type(leaf, chunk);
3078         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
3079         for (i = 0; i < num_stripes; i++) {
3080                 map->stripes[i].physical =
3081                         btrfs_stripe_offset_nr(leaf, chunk, i);
3082                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
3083                 read_extent_buffer(leaf, uuid, (unsigned long)
3084                                    btrfs_stripe_dev_uuid_nr(chunk, i),
3085                                    BTRFS_UUID_SIZE);
3086                 map->stripes[i].dev = btrfs_find_device(root, devid, uuid,
3087                                                         NULL);
3088                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
3089                         kfree(map);
3090                         free_extent_map(em);
3091                         return -EIO;
3092                 }
3093                 if (!map->stripes[i].dev) {
3094                         map->stripes[i].dev =
3095                                 add_missing_dev(root, devid, uuid);
3096                         if (!map->stripes[i].dev) {
3097                                 kfree(map);
3098                                 free_extent_map(em);
3099                                 return -EIO;
3100                         }
3101                 }
3102                 map->stripes[i].dev->in_fs_metadata = 1;
3103         }
3104
3105         spin_lock(&map_tree->map_tree.lock);
3106         ret = add_extent_mapping(&map_tree->map_tree, em);
3107         spin_unlock(&map_tree->map_tree.lock);
3108         BUG_ON(ret);
3109         free_extent_map(em);
3110
3111         return 0;
3112 }
3113
3114 static int fill_device_from_item(struct extent_buffer *leaf,
3115                                  struct btrfs_dev_item *dev_item,
3116                                  struct btrfs_device *device)
3117 {
3118         unsigned long ptr;
3119
3120         device->devid = btrfs_device_id(leaf, dev_item);
3121         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
3122         device->total_bytes = device->disk_total_bytes;
3123         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
3124         device->type = btrfs_device_type(leaf, dev_item);
3125         device->io_align = btrfs_device_io_align(leaf, dev_item);
3126         device->io_width = btrfs_device_io_width(leaf, dev_item);
3127         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
3128
3129         ptr = (unsigned long)btrfs_device_uuid(dev_item);
3130         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
3131
3132         return 0;
3133 }
3134
3135 static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
3136 {
3137         struct btrfs_fs_devices *fs_devices;
3138         int ret;
3139
3140         mutex_lock(&uuid_mutex);
3141
3142         fs_devices = root->fs_info->fs_devices->seed;
3143         while (fs_devices) {
3144                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
3145                         ret = 0;
3146                         goto out;
3147                 }
3148                 fs_devices = fs_devices->seed;
3149         }
3150
3151         fs_devices = find_fsid(fsid);
3152         if (!fs_devices) {
3153                 ret = -ENOENT;
3154                 goto out;
3155         }
3156
3157         fs_devices = clone_fs_devices(fs_devices);
3158         if (IS_ERR(fs_devices)) {
3159                 ret = PTR_ERR(fs_devices);
3160                 goto out;
3161         }
3162
3163         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
3164                                    root->fs_info->bdev_holder);
3165         if (ret)
3166                 goto out;
3167
3168         if (!fs_devices->seeding) {
3169                 __btrfs_close_devices(fs_devices);
3170                 free_fs_devices(fs_devices);
3171                 ret = -EINVAL;
3172                 goto out;
3173         }
3174
3175         fs_devices->seed = root->fs_info->fs_devices->seed;
3176         root->fs_info->fs_devices->seed = fs_devices;
3177 out:
3178         mutex_unlock(&uuid_mutex);
3179         return ret;
3180 }
3181
3182 static int read_one_dev(struct btrfs_root *root,
3183                         struct extent_buffer *leaf,
3184                         struct btrfs_dev_item *dev_item)
3185 {
3186         struct btrfs_device *device;
3187         u64 devid;
3188         int ret;
3189         u8 fs_uuid[BTRFS_UUID_SIZE];
3190         u8 dev_uuid[BTRFS_UUID_SIZE];
3191
3192         devid = btrfs_device_id(leaf, dev_item);
3193         read_extent_buffer(leaf, dev_uuid,
3194                            (unsigned long)btrfs_device_uuid(dev_item),
3195                            BTRFS_UUID_SIZE);
3196         read_extent_buffer(leaf, fs_uuid,
3197                            (unsigned long)btrfs_device_fsid(dev_item),
3198                            BTRFS_UUID_SIZE);
3199
3200         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
3201                 ret = open_seed_devices(root, fs_uuid);
3202                 if (ret && !btrfs_test_opt(root, DEGRADED))
3203                         return ret;
3204         }
3205
3206         device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
3207         if (!device || !device->bdev) {
3208                 if (!btrfs_test_opt(root, DEGRADED))
3209                         return -EIO;
3210
3211                 if (!device) {
3212                         printk(KERN_WARNING "warning devid %llu missing\n",
3213                                (unsigned long long)devid);
3214                         device = add_missing_dev(root, devid, dev_uuid);
3215                         if (!device)
3216                                 return -ENOMEM;
3217                 }
3218         }
3219
3220         if (device->fs_devices != root->fs_info->fs_devices) {
3221                 BUG_ON(device->writeable);
3222                 if (device->generation !=
3223                     btrfs_device_generation(leaf, dev_item))
3224                         return -EINVAL;
3225         }
3226
3227         fill_device_from_item(leaf, dev_item, device);
3228         device->dev_root = root->fs_info->dev_root;
3229         device->in_fs_metadata = 1;
3230         if (device->writeable)
3231                 device->fs_devices->total_rw_bytes += device->total_bytes;
3232         ret = 0;
3233         return ret;
3234 }
3235
3236 int btrfs_read_super_device(struct btrfs_root *root, struct extent_buffer *buf)
3237 {
3238         struct btrfs_dev_item *dev_item;
3239
3240         dev_item = (struct btrfs_dev_item *)offsetof(struct btrfs_super_block,
3241                                                      dev_item);
3242         return read_one_dev(root, buf, dev_item);
3243 }
3244
3245 int btrfs_read_sys_array(struct btrfs_root *root)
3246 {
3247         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
3248         struct extent_buffer *sb;
3249         struct btrfs_disk_key *disk_key;
3250         struct btrfs_chunk *chunk;
3251         u8 *ptr;
3252         unsigned long sb_ptr;
3253         int ret = 0;
3254         u32 num_stripes;
3255         u32 array_size;
3256         u32 len = 0;
3257         u32 cur;
3258         struct btrfs_key key;
3259
3260         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
3261                                           BTRFS_SUPER_INFO_SIZE);
3262         if (!sb)
3263                 return -ENOMEM;
3264         btrfs_set_buffer_uptodate(sb);
3265         btrfs_set_buffer_lockdep_class(sb, 0);
3266
3267         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
3268         array_size = btrfs_super_sys_array_size(super_copy);
3269
3270         ptr = super_copy->sys_chunk_array;
3271         sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
3272         cur = 0;
3273
3274         while (cur < array_size) {
3275                 disk_key = (struct btrfs_disk_key *)ptr;
3276                 btrfs_disk_key_to_cpu(&key, disk_key);
3277
3278                 len = sizeof(*disk_key); ptr += len;
3279                 sb_ptr += len;
3280                 cur += len;
3281
3282                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
3283                         chunk = (struct btrfs_chunk *)sb_ptr;
3284                         ret = read_one_chunk(root, &key, sb, chunk);
3285                         if (ret)
3286                                 break;
3287                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
3288                         len = btrfs_chunk_item_size(num_stripes);
3289                 } else {
3290                         ret = -EIO;
3291                         break;
3292                 }
3293                 ptr += len;
3294                 sb_ptr += len;
3295                 cur += len;
3296         }
3297         free_extent_buffer(sb);
3298         return ret;
3299 }
3300
3301 int btrfs_read_chunk_tree(struct btrfs_root *root)
3302 {
3303         struct btrfs_path *path;
3304         struct extent_buffer *leaf;
3305         struct btrfs_key key;
3306         struct btrfs_key found_key;
3307         int ret;
3308         int slot;
3309
3310         root = root->fs_info->chunk_root;
3311
3312         path = btrfs_alloc_path();
3313         if (!path)
3314                 return -ENOMEM;
3315
3316         /* first we search for all of the device items, and then we
3317          * read in all of the chunk items.  This way we can create chunk
3318          * mappings that reference all of the devices that are afound
3319          */
3320         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
3321         key.offset = 0;
3322         key.type = 0;
3323 again:
3324         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3325         while (1) {
3326                 leaf = path->nodes[0];
3327                 slot = path->slots[0];
3328                 if (slot >= btrfs_header_nritems(leaf)) {
3329                         ret = btrfs_next_leaf(root, path);
3330                         if (ret == 0)
3331                                 continue;
3332                         if (ret < 0)
3333                                 goto error;
3334                         break;
3335                 }
3336                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3337                 if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
3338                         if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
3339                                 break;
3340                         if (found_key.type == BTRFS_DEV_ITEM_KEY) {
3341                                 struct btrfs_dev_item *dev_item;
3342                                 dev_item = btrfs_item_ptr(leaf, slot,
3343                                                   struct btrfs_dev_item);
3344                                 ret = read_one_dev(root, leaf, dev_item);
3345                                 if (ret)
3346                                         goto error;
3347                         }
3348                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
3349                         struct btrfs_chunk *chunk;
3350                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
3351                         ret = read_one_chunk(root, &found_key, leaf, chunk);
3352                         if (ret)
3353                                 goto error;
3354                 }
3355                 path->slots[0]++;
3356         }
3357         if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
3358                 key.objectid = 0;
3359                 btrfs_release_path(root, path);
3360                 goto again;
3361         }
3362         ret = 0;
3363 error:
3364         btrfs_free_path(path);
3365         return ret;
3366 }