Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs...
[linux-2.6.git] / fs / btrfs / volumes.c
1 /*
2  * Copyright (C) 2007 Oracle.  All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public
6  * License v2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public
14  * License along with this program; if not, write to the
15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16  * Boston, MA 021110-1307, USA.
17  */
18 #include <linux/sched.h>
19 #include <linux/bio.h>
20 #include <linux/slab.h>
21 #include <linux/buffer_head.h>
22 #include <linux/blkdev.h>
23 #include <linux/random.h>
24 #include <linux/iocontext.h>
25 #include <asm/div64.h>
26 #include "compat.h"
27 #include "ctree.h"
28 #include "extent_map.h"
29 #include "disk-io.h"
30 #include "transaction.h"
31 #include "print-tree.h"
32 #include "volumes.h"
33 #include "async-thread.h"
34
35 struct map_lookup {
36         u64 type;
37         int io_align;
38         int io_width;
39         int stripe_len;
40         int sector_size;
41         int num_stripes;
42         int sub_stripes;
43         struct btrfs_bio_stripe stripes[];
44 };
45
46 static int init_first_rw_device(struct btrfs_trans_handle *trans,
47                                 struct btrfs_root *root,
48                                 struct btrfs_device *device);
49 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
50
51 #define map_lookup_size(n) (sizeof(struct map_lookup) + \
52                             (sizeof(struct btrfs_bio_stripe) * (n)))
53
54 static DEFINE_MUTEX(uuid_mutex);
55 static LIST_HEAD(fs_uuids);
56
57 void btrfs_lock_volumes(void)
58 {
59         mutex_lock(&uuid_mutex);
60 }
61
62 void btrfs_unlock_volumes(void)
63 {
64         mutex_unlock(&uuid_mutex);
65 }
66
67 static void lock_chunks(struct btrfs_root *root)
68 {
69         mutex_lock(&root->fs_info->chunk_mutex);
70 }
71
72 static void unlock_chunks(struct btrfs_root *root)
73 {
74         mutex_unlock(&root->fs_info->chunk_mutex);
75 }
76
77 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
78 {
79         struct btrfs_device *device;
80         WARN_ON(fs_devices->opened);
81         while (!list_empty(&fs_devices->devices)) {
82                 device = list_entry(fs_devices->devices.next,
83                                     struct btrfs_device, dev_list);
84                 list_del(&device->dev_list);
85                 kfree(device->name);
86                 kfree(device);
87         }
88         kfree(fs_devices);
89 }
90
91 int btrfs_cleanup_fs_uuids(void)
92 {
93         struct btrfs_fs_devices *fs_devices;
94
95         while (!list_empty(&fs_uuids)) {
96                 fs_devices = list_entry(fs_uuids.next,
97                                         struct btrfs_fs_devices, list);
98                 list_del(&fs_devices->list);
99                 free_fs_devices(fs_devices);
100         }
101         return 0;
102 }
103
104 static noinline struct btrfs_device *__find_device(struct list_head *head,
105                                                    u64 devid, u8 *uuid)
106 {
107         struct btrfs_device *dev;
108
109         list_for_each_entry(dev, head, dev_list) {
110                 if (dev->devid == devid &&
111                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
112                         return dev;
113                 }
114         }
115         return NULL;
116 }
117
118 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
119 {
120         struct btrfs_fs_devices *fs_devices;
121
122         list_for_each_entry(fs_devices, &fs_uuids, list) {
123                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
124                         return fs_devices;
125         }
126         return NULL;
127 }
128
129 static void requeue_list(struct btrfs_pending_bios *pending_bios,
130                         struct bio *head, struct bio *tail)
131 {
132
133         struct bio *old_head;
134
135         old_head = pending_bios->head;
136         pending_bios->head = head;
137         if (pending_bios->tail)
138                 tail->bi_next = old_head;
139         else
140                 pending_bios->tail = tail;
141 }
142
143 /*
144  * we try to collect pending bios for a device so we don't get a large
145  * number of procs sending bios down to the same device.  This greatly
146  * improves the schedulers ability to collect and merge the bios.
147  *
148  * But, it also turns into a long list of bios to process and that is sure
149  * to eventually make the worker thread block.  The solution here is to
150  * make some progress and then put this work struct back at the end of
151  * the list if the block device is congested.  This way, multiple devices
152  * can make progress from a single worker thread.
153  */
154 static noinline int run_scheduled_bios(struct btrfs_device *device)
155 {
156         struct bio *pending;
157         struct backing_dev_info *bdi;
158         struct btrfs_fs_info *fs_info;
159         struct btrfs_pending_bios *pending_bios;
160         struct bio *tail;
161         struct bio *cur;
162         int again = 0;
163         unsigned long num_run;
164         unsigned long num_sync_run;
165         unsigned long batch_run = 0;
166         unsigned long limit;
167         unsigned long last_waited = 0;
168         int force_reg = 0;
169
170         bdi = blk_get_backing_dev_info(device->bdev);
171         fs_info = device->dev_root->fs_info;
172         limit = btrfs_async_submit_limit(fs_info);
173         limit = limit * 2 / 3;
174
175         /* we want to make sure that every time we switch from the sync
176          * list to the normal list, we unplug
177          */
178         num_sync_run = 0;
179
180 loop:
181         spin_lock(&device->io_lock);
182
183 loop_lock:
184         num_run = 0;
185
186         /* take all the bios off the list at once and process them
187          * later on (without the lock held).  But, remember the
188          * tail and other pointers so the bios can be properly reinserted
189          * into the list if we hit congestion
190          */
191         if (!force_reg && device->pending_sync_bios.head) {
192                 pending_bios = &device->pending_sync_bios;
193                 force_reg = 1;
194         } else {
195                 pending_bios = &device->pending_bios;
196                 force_reg = 0;
197         }
198
199         pending = pending_bios->head;
200         tail = pending_bios->tail;
201         WARN_ON(pending && !tail);
202
203         /*
204          * if pending was null this time around, no bios need processing
205          * at all and we can stop.  Otherwise it'll loop back up again
206          * and do an additional check so no bios are missed.
207          *
208          * device->running_pending is used to synchronize with the
209          * schedule_bio code.
210          */
211         if (device->pending_sync_bios.head == NULL &&
212             device->pending_bios.head == NULL) {
213                 again = 0;
214                 device->running_pending = 0;
215         } else {
216                 again = 1;
217                 device->running_pending = 1;
218         }
219
220         pending_bios->head = NULL;
221         pending_bios->tail = NULL;
222
223         spin_unlock(&device->io_lock);
224
225         /*
226          * if we're doing the regular priority list, make sure we unplug
227          * for any high prio bios we've sent down
228          */
229         if (pending_bios == &device->pending_bios && num_sync_run > 0) {
230                 num_sync_run = 0;
231                 blk_run_backing_dev(bdi, NULL);
232         }
233
234         while (pending) {
235
236                 rmb();
237                 /* we want to work on both lists, but do more bios on the
238                  * sync list than the regular list
239                  */
240                 if ((num_run > 32 &&
241                     pending_bios != &device->pending_sync_bios &&
242                     device->pending_sync_bios.head) ||
243                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
244                     device->pending_bios.head)) {
245                         spin_lock(&device->io_lock);
246                         requeue_list(pending_bios, pending, tail);
247                         goto loop_lock;
248                 }
249
250                 cur = pending;
251                 pending = pending->bi_next;
252                 cur->bi_next = NULL;
253                 atomic_dec(&fs_info->nr_async_bios);
254
255                 if (atomic_read(&fs_info->nr_async_bios) < limit &&
256                     waitqueue_active(&fs_info->async_submit_wait))
257                         wake_up(&fs_info->async_submit_wait);
258
259                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
260
261                 if (bio_rw_flagged(cur, BIO_RW_SYNCIO))
262                         num_sync_run++;
263
264                 submit_bio(cur->bi_rw, cur);
265                 num_run++;
266                 batch_run++;
267                 if (need_resched()) {
268                         if (num_sync_run) {
269                                 blk_run_backing_dev(bdi, NULL);
270                                 num_sync_run = 0;
271                         }
272                         cond_resched();
273                 }
274
275                 /*
276                  * we made progress, there is more work to do and the bdi
277                  * is now congested.  Back off and let other work structs
278                  * run instead
279                  */
280                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
281                     fs_info->fs_devices->open_devices > 1) {
282                         struct io_context *ioc;
283
284                         ioc = current->io_context;
285
286                         /*
287                          * the main goal here is that we don't want to
288                          * block if we're going to be able to submit
289                          * more requests without blocking.
290                          *
291                          * This code does two great things, it pokes into
292                          * the elevator code from a filesystem _and_
293                          * it makes assumptions about how batching works.
294                          */
295                         if (ioc && ioc->nr_batch_requests > 0 &&
296                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
297                             (last_waited == 0 ||
298                              ioc->last_waited == last_waited)) {
299                                 /*
300                                  * we want to go through our batch of
301                                  * requests and stop.  So, we copy out
302                                  * the ioc->last_waited time and test
303                                  * against it before looping
304                                  */
305                                 last_waited = ioc->last_waited;
306                                 if (need_resched()) {
307                                         if (num_sync_run) {
308                                                 blk_run_backing_dev(bdi, NULL);
309                                                 num_sync_run = 0;
310                                         }
311                                         cond_resched();
312                                 }
313                                 continue;
314                         }
315                         spin_lock(&device->io_lock);
316                         requeue_list(pending_bios, pending, tail);
317                         device->running_pending = 1;
318
319                         spin_unlock(&device->io_lock);
320                         btrfs_requeue_work(&device->work);
321                         goto done;
322                 }
323         }
324
325         if (num_sync_run) {
326                 num_sync_run = 0;
327                 blk_run_backing_dev(bdi, NULL);
328         }
329         /*
330          * IO has already been through a long path to get here.  Checksumming,
331          * async helper threads, perhaps compression.  We've done a pretty
332          * good job of collecting a batch of IO and should just unplug
333          * the device right away.
334          *
335          * This will help anyone who is waiting on the IO, they might have
336          * already unplugged, but managed to do so before the bio they
337          * cared about found its way down here.
338          */
339         blk_run_backing_dev(bdi, NULL);
340
341         cond_resched();
342         if (again)
343                 goto loop;
344
345         spin_lock(&device->io_lock);
346         if (device->pending_bios.head || device->pending_sync_bios.head)
347                 goto loop_lock;
348         spin_unlock(&device->io_lock);
349
350 done:
351         return 0;
352 }
353
354 static void pending_bios_fn(struct btrfs_work *work)
355 {
356         struct btrfs_device *device;
357
358         device = container_of(work, struct btrfs_device, work);
359         run_scheduled_bios(device);
360 }
361
362 static noinline int device_list_add(const char *path,
363                            struct btrfs_super_block *disk_super,
364                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
365 {
366         struct btrfs_device *device;
367         struct btrfs_fs_devices *fs_devices;
368         u64 found_transid = btrfs_super_generation(disk_super);
369         char *name;
370
371         fs_devices = find_fsid(disk_super->fsid);
372         if (!fs_devices) {
373                 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
374                 if (!fs_devices)
375                         return -ENOMEM;
376                 INIT_LIST_HEAD(&fs_devices->devices);
377                 INIT_LIST_HEAD(&fs_devices->alloc_list);
378                 list_add(&fs_devices->list, &fs_uuids);
379                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
380                 fs_devices->latest_devid = devid;
381                 fs_devices->latest_trans = found_transid;
382                 mutex_init(&fs_devices->device_list_mutex);
383                 device = NULL;
384         } else {
385                 device = __find_device(&fs_devices->devices, devid,
386                                        disk_super->dev_item.uuid);
387         }
388         if (!device) {
389                 if (fs_devices->opened)
390                         return -EBUSY;
391
392                 device = kzalloc(sizeof(*device), GFP_NOFS);
393                 if (!device) {
394                         /* we can safely leave the fs_devices entry around */
395                         return -ENOMEM;
396                 }
397                 device->devid = devid;
398                 device->work.func = pending_bios_fn;
399                 memcpy(device->uuid, disk_super->dev_item.uuid,
400                        BTRFS_UUID_SIZE);
401                 device->barriers = 1;
402                 spin_lock_init(&device->io_lock);
403                 device->name = kstrdup(path, GFP_NOFS);
404                 if (!device->name) {
405                         kfree(device);
406                         return -ENOMEM;
407                 }
408                 INIT_LIST_HEAD(&device->dev_alloc_list);
409
410                 mutex_lock(&fs_devices->device_list_mutex);
411                 list_add(&device->dev_list, &fs_devices->devices);
412                 mutex_unlock(&fs_devices->device_list_mutex);
413
414                 device->fs_devices = fs_devices;
415                 fs_devices->num_devices++;
416         } else if (strcmp(device->name, path)) {
417                 name = kstrdup(path, GFP_NOFS);
418                 if (!name)
419                         return -ENOMEM;
420                 kfree(device->name);
421                 device->name = name;
422         }
423
424         if (found_transid > fs_devices->latest_trans) {
425                 fs_devices->latest_devid = devid;
426                 fs_devices->latest_trans = found_transid;
427         }
428         *fs_devices_ret = fs_devices;
429         return 0;
430 }
431
432 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
433 {
434         struct btrfs_fs_devices *fs_devices;
435         struct btrfs_device *device;
436         struct btrfs_device *orig_dev;
437
438         fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
439         if (!fs_devices)
440                 return ERR_PTR(-ENOMEM);
441
442         INIT_LIST_HEAD(&fs_devices->devices);
443         INIT_LIST_HEAD(&fs_devices->alloc_list);
444         INIT_LIST_HEAD(&fs_devices->list);
445         mutex_init(&fs_devices->device_list_mutex);
446         fs_devices->latest_devid = orig->latest_devid;
447         fs_devices->latest_trans = orig->latest_trans;
448         memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));
449
450         mutex_lock(&orig->device_list_mutex);
451         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
452                 device = kzalloc(sizeof(*device), GFP_NOFS);
453                 if (!device)
454                         goto error;
455
456                 device->name = kstrdup(orig_dev->name, GFP_NOFS);
457                 if (!device->name) {
458                         kfree(device);
459                         goto error;
460                 }
461
462                 device->devid = orig_dev->devid;
463                 device->work.func = pending_bios_fn;
464                 memcpy(device->uuid, orig_dev->uuid, sizeof(device->uuid));
465                 device->barriers = 1;
466                 spin_lock_init(&device->io_lock);
467                 INIT_LIST_HEAD(&device->dev_list);
468                 INIT_LIST_HEAD(&device->dev_alloc_list);
469
470                 list_add(&device->dev_list, &fs_devices->devices);
471                 device->fs_devices = fs_devices;
472                 fs_devices->num_devices++;
473         }
474         mutex_unlock(&orig->device_list_mutex);
475         return fs_devices;
476 error:
477         mutex_unlock(&orig->device_list_mutex);
478         free_fs_devices(fs_devices);
479         return ERR_PTR(-ENOMEM);
480 }
481
482 int btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices)
483 {
484         struct btrfs_device *device, *next;
485
486         mutex_lock(&uuid_mutex);
487 again:
488         mutex_lock(&fs_devices->device_list_mutex);
489         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
490                 if (device->in_fs_metadata)
491                         continue;
492
493                 if (device->bdev) {
494                         close_bdev_exclusive(device->bdev, device->mode);
495                         device->bdev = NULL;
496                         fs_devices->open_devices--;
497                 }
498                 if (device->writeable) {
499                         list_del_init(&device->dev_alloc_list);
500                         device->writeable = 0;
501                         fs_devices->rw_devices--;
502                 }
503                 list_del_init(&device->dev_list);
504                 fs_devices->num_devices--;
505                 kfree(device->name);
506                 kfree(device);
507         }
508         mutex_unlock(&fs_devices->device_list_mutex);
509
510         if (fs_devices->seed) {
511                 fs_devices = fs_devices->seed;
512                 goto again;
513         }
514
515         mutex_unlock(&uuid_mutex);
516         return 0;
517 }
518
519 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
520 {
521         struct btrfs_device *device;
522
523         if (--fs_devices->opened > 0)
524                 return 0;
525
526         list_for_each_entry(device, &fs_devices->devices, dev_list) {
527                 if (device->bdev) {
528                         close_bdev_exclusive(device->bdev, device->mode);
529                         fs_devices->open_devices--;
530                 }
531                 if (device->writeable) {
532                         list_del_init(&device->dev_alloc_list);
533                         fs_devices->rw_devices--;
534                 }
535
536                 device->bdev = NULL;
537                 device->writeable = 0;
538                 device->in_fs_metadata = 0;
539         }
540         WARN_ON(fs_devices->open_devices);
541         WARN_ON(fs_devices->rw_devices);
542         fs_devices->opened = 0;
543         fs_devices->seeding = 0;
544
545         return 0;
546 }
547
548 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
549 {
550         struct btrfs_fs_devices *seed_devices = NULL;
551         int ret;
552
553         mutex_lock(&uuid_mutex);
554         ret = __btrfs_close_devices(fs_devices);
555         if (!fs_devices->opened) {
556                 seed_devices = fs_devices->seed;
557                 fs_devices->seed = NULL;
558         }
559         mutex_unlock(&uuid_mutex);
560
561         while (seed_devices) {
562                 fs_devices = seed_devices;
563                 seed_devices = fs_devices->seed;
564                 __btrfs_close_devices(fs_devices);
565                 free_fs_devices(fs_devices);
566         }
567         return ret;
568 }
569
570 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
571                                 fmode_t flags, void *holder)
572 {
573         struct block_device *bdev;
574         struct list_head *head = &fs_devices->devices;
575         struct btrfs_device *device;
576         struct block_device *latest_bdev = NULL;
577         struct buffer_head *bh;
578         struct btrfs_super_block *disk_super;
579         u64 latest_devid = 0;
580         u64 latest_transid = 0;
581         u64 devid;
582         int seeding = 1;
583         int ret = 0;
584
585         list_for_each_entry(device, head, dev_list) {
586                 if (device->bdev)
587                         continue;
588                 if (!device->name)
589                         continue;
590
591                 bdev = open_bdev_exclusive(device->name, flags, holder);
592                 if (IS_ERR(bdev)) {
593                         printk(KERN_INFO "open %s failed\n", device->name);
594                         goto error;
595                 }
596                 set_blocksize(bdev, 4096);
597
598                 bh = btrfs_read_dev_super(bdev);
599                 if (!bh)
600                         goto error_close;
601
602                 disk_super = (struct btrfs_super_block *)bh->b_data;
603                 devid = btrfs_stack_device_id(&disk_super->dev_item);
604                 if (devid != device->devid)
605                         goto error_brelse;
606
607                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
608                            BTRFS_UUID_SIZE))
609                         goto error_brelse;
610
611                 device->generation = btrfs_super_generation(disk_super);
612                 if (!latest_transid || device->generation > latest_transid) {
613                         latest_devid = devid;
614                         latest_transid = device->generation;
615                         latest_bdev = bdev;
616                 }
617
618                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
619                         device->writeable = 0;
620                 } else {
621                         device->writeable = !bdev_read_only(bdev);
622                         seeding = 0;
623                 }
624
625                 device->bdev = bdev;
626                 device->in_fs_metadata = 0;
627                 device->mode = flags;
628
629                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
630                         fs_devices->rotating = 1;
631
632                 fs_devices->open_devices++;
633                 if (device->writeable) {
634                         fs_devices->rw_devices++;
635                         list_add(&device->dev_alloc_list,
636                                  &fs_devices->alloc_list);
637                 }
638                 continue;
639
640 error_brelse:
641                 brelse(bh);
642 error_close:
643                 close_bdev_exclusive(bdev, FMODE_READ);
644 error:
645                 continue;
646         }
647         if (fs_devices->open_devices == 0) {
648                 ret = -EIO;
649                 goto out;
650         }
651         fs_devices->seeding = seeding;
652         fs_devices->opened = 1;
653         fs_devices->latest_bdev = latest_bdev;
654         fs_devices->latest_devid = latest_devid;
655         fs_devices->latest_trans = latest_transid;
656         fs_devices->total_rw_bytes = 0;
657 out:
658         return ret;
659 }
660
661 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
662                        fmode_t flags, void *holder)
663 {
664         int ret;
665
666         mutex_lock(&uuid_mutex);
667         if (fs_devices->opened) {
668                 fs_devices->opened++;
669                 ret = 0;
670         } else {
671                 ret = __btrfs_open_devices(fs_devices, flags, holder);
672         }
673         mutex_unlock(&uuid_mutex);
674         return ret;
675 }
676
677 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
678                           struct btrfs_fs_devices **fs_devices_ret)
679 {
680         struct btrfs_super_block *disk_super;
681         struct block_device *bdev;
682         struct buffer_head *bh;
683         int ret;
684         u64 devid;
685         u64 transid;
686
687         mutex_lock(&uuid_mutex);
688
689         bdev = open_bdev_exclusive(path, flags, holder);
690
691         if (IS_ERR(bdev)) {
692                 ret = PTR_ERR(bdev);
693                 goto error;
694         }
695
696         ret = set_blocksize(bdev, 4096);
697         if (ret)
698                 goto error_close;
699         bh = btrfs_read_dev_super(bdev);
700         if (!bh) {
701                 ret = -EIO;
702                 goto error_close;
703         }
704         disk_super = (struct btrfs_super_block *)bh->b_data;
705         devid = btrfs_stack_device_id(&disk_super->dev_item);
706         transid = btrfs_super_generation(disk_super);
707         if (disk_super->label[0])
708                 printk(KERN_INFO "device label %s ", disk_super->label);
709         else {
710                 /* FIXME, make a readl uuid parser */
711                 printk(KERN_INFO "device fsid %llx-%llx ",
712                        *(unsigned long long *)disk_super->fsid,
713                        *(unsigned long long *)(disk_super->fsid + 8));
714         }
715         printk(KERN_CONT "devid %llu transid %llu %s\n",
716                (unsigned long long)devid, (unsigned long long)transid, path);
717         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
718
719         brelse(bh);
720 error_close:
721         close_bdev_exclusive(bdev, flags);
722 error:
723         mutex_unlock(&uuid_mutex);
724         return ret;
725 }
726
727 /*
728  * this uses a pretty simple search, the expectation is that it is
729  * called very infrequently and that a given device has a small number
730  * of extents
731  */
732 int find_free_dev_extent(struct btrfs_trans_handle *trans,
733                          struct btrfs_device *device, u64 num_bytes,
734                          u64 *start, u64 *max_avail)
735 {
736         struct btrfs_key key;
737         struct btrfs_root *root = device->dev_root;
738         struct btrfs_dev_extent *dev_extent = NULL;
739         struct btrfs_path *path;
740         u64 hole_size = 0;
741         u64 last_byte = 0;
742         u64 search_start = 0;
743         u64 search_end = device->total_bytes;
744         int ret;
745         int slot = 0;
746         int start_found;
747         struct extent_buffer *l;
748
749         path = btrfs_alloc_path();
750         if (!path)
751                 return -ENOMEM;
752         path->reada = 2;
753         start_found = 0;
754
755         /* FIXME use last free of some kind */
756
757         /* we don't want to overwrite the superblock on the drive,
758          * so we make sure to start at an offset of at least 1MB
759          */
760         search_start = max((u64)1024 * 1024, search_start);
761
762         if (root->fs_info->alloc_start + num_bytes <= device->total_bytes)
763                 search_start = max(root->fs_info->alloc_start, search_start);
764
765         key.objectid = device->devid;
766         key.offset = search_start;
767         key.type = BTRFS_DEV_EXTENT_KEY;
768         ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
769         if (ret < 0)
770                 goto error;
771         if (ret > 0) {
772                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
773                 if (ret < 0)
774                         goto error;
775                 if (ret > 0)
776                         start_found = 1;
777         }
778         l = path->nodes[0];
779         btrfs_item_key_to_cpu(l, &key, path->slots[0]);
780         while (1) {
781                 l = path->nodes[0];
782                 slot = path->slots[0];
783                 if (slot >= btrfs_header_nritems(l)) {
784                         ret = btrfs_next_leaf(root, path);
785                         if (ret == 0)
786                                 continue;
787                         if (ret < 0)
788                                 goto error;
789 no_more_items:
790                         if (!start_found) {
791                                 if (search_start >= search_end) {
792                                         ret = -ENOSPC;
793                                         goto error;
794                                 }
795                                 *start = search_start;
796                                 start_found = 1;
797                                 goto check_pending;
798                         }
799                         *start = last_byte > search_start ?
800                                 last_byte : search_start;
801                         if (search_end <= *start) {
802                                 ret = -ENOSPC;
803                                 goto error;
804                         }
805                         goto check_pending;
806                 }
807                 btrfs_item_key_to_cpu(l, &key, slot);
808
809                 if (key.objectid < device->devid)
810                         goto next;
811
812                 if (key.objectid > device->devid)
813                         goto no_more_items;
814
815                 if (key.offset >= search_start && key.offset > last_byte &&
816                     start_found) {
817                         if (last_byte < search_start)
818                                 last_byte = search_start;
819                         hole_size = key.offset - last_byte;
820
821                         if (hole_size > *max_avail)
822                                 *max_avail = hole_size;
823
824                         if (key.offset > last_byte &&
825                             hole_size >= num_bytes) {
826                                 *start = last_byte;
827                                 goto check_pending;
828                         }
829                 }
830                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
831                         goto next;
832
833                 start_found = 1;
834                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
835                 last_byte = key.offset + btrfs_dev_extent_length(l, dev_extent);
836 next:
837                 path->slots[0]++;
838                 cond_resched();
839         }
840 check_pending:
841         /* we have to make sure we didn't find an extent that has already
842          * been allocated by the map tree or the original allocation
843          */
844         BUG_ON(*start < search_start);
845
846         if (*start + num_bytes > search_end) {
847                 ret = -ENOSPC;
848                 goto error;
849         }
850         /* check for pending inserts here */
851         ret = 0;
852
853 error:
854         btrfs_free_path(path);
855         return ret;
856 }
857
858 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
859                           struct btrfs_device *device,
860                           u64 start)
861 {
862         int ret;
863         struct btrfs_path *path;
864         struct btrfs_root *root = device->dev_root;
865         struct btrfs_key key;
866         struct btrfs_key found_key;
867         struct extent_buffer *leaf = NULL;
868         struct btrfs_dev_extent *extent = NULL;
869
870         path = btrfs_alloc_path();
871         if (!path)
872                 return -ENOMEM;
873
874         key.objectid = device->devid;
875         key.offset = start;
876         key.type = BTRFS_DEV_EXTENT_KEY;
877
878         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
879         if (ret > 0) {
880                 ret = btrfs_previous_item(root, path, key.objectid,
881                                           BTRFS_DEV_EXTENT_KEY);
882                 BUG_ON(ret);
883                 leaf = path->nodes[0];
884                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
885                 extent = btrfs_item_ptr(leaf, path->slots[0],
886                                         struct btrfs_dev_extent);
887                 BUG_ON(found_key.offset > start || found_key.offset +
888                        btrfs_dev_extent_length(leaf, extent) < start);
889                 ret = 0;
890         } else if (ret == 0) {
891                 leaf = path->nodes[0];
892                 extent = btrfs_item_ptr(leaf, path->slots[0],
893                                         struct btrfs_dev_extent);
894         }
895         BUG_ON(ret);
896
897         if (device->bytes_used > 0)
898                 device->bytes_used -= btrfs_dev_extent_length(leaf, extent);
899         ret = btrfs_del_item(trans, root, path);
900         BUG_ON(ret);
901
902         btrfs_free_path(path);
903         return ret;
904 }
905
906 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
907                            struct btrfs_device *device,
908                            u64 chunk_tree, u64 chunk_objectid,
909                            u64 chunk_offset, u64 start, u64 num_bytes)
910 {
911         int ret;
912         struct btrfs_path *path;
913         struct btrfs_root *root = device->dev_root;
914         struct btrfs_dev_extent *extent;
915         struct extent_buffer *leaf;
916         struct btrfs_key key;
917
918         WARN_ON(!device->in_fs_metadata);
919         path = btrfs_alloc_path();
920         if (!path)
921                 return -ENOMEM;
922
923         key.objectid = device->devid;
924         key.offset = start;
925         key.type = BTRFS_DEV_EXTENT_KEY;
926         ret = btrfs_insert_empty_item(trans, root, path, &key,
927                                       sizeof(*extent));
928         BUG_ON(ret);
929
930         leaf = path->nodes[0];
931         extent = btrfs_item_ptr(leaf, path->slots[0],
932                                 struct btrfs_dev_extent);
933         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
934         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
935         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
936
937         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
938                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
939                     BTRFS_UUID_SIZE);
940
941         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
942         btrfs_mark_buffer_dirty(leaf);
943         btrfs_free_path(path);
944         return ret;
945 }
946
947 static noinline int find_next_chunk(struct btrfs_root *root,
948                                     u64 objectid, u64 *offset)
949 {
950         struct btrfs_path *path;
951         int ret;
952         struct btrfs_key key;
953         struct btrfs_chunk *chunk;
954         struct btrfs_key found_key;
955
956         path = btrfs_alloc_path();
957         BUG_ON(!path);
958
959         key.objectid = objectid;
960         key.offset = (u64)-1;
961         key.type = BTRFS_CHUNK_ITEM_KEY;
962
963         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
964         if (ret < 0)
965                 goto error;
966
967         BUG_ON(ret == 0);
968
969         ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
970         if (ret) {
971                 *offset = 0;
972         } else {
973                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
974                                       path->slots[0]);
975                 if (found_key.objectid != objectid)
976                         *offset = 0;
977                 else {
978                         chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
979                                                struct btrfs_chunk);
980                         *offset = found_key.offset +
981                                 btrfs_chunk_length(path->nodes[0], chunk);
982                 }
983         }
984         ret = 0;
985 error:
986         btrfs_free_path(path);
987         return ret;
988 }
989
990 static noinline int find_next_devid(struct btrfs_root *root, u64 *objectid)
991 {
992         int ret;
993         struct btrfs_key key;
994         struct btrfs_key found_key;
995         struct btrfs_path *path;
996
997         root = root->fs_info->chunk_root;
998
999         path = btrfs_alloc_path();
1000         if (!path)
1001                 return -ENOMEM;
1002
1003         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1004         key.type = BTRFS_DEV_ITEM_KEY;
1005         key.offset = (u64)-1;
1006
1007         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1008         if (ret < 0)
1009                 goto error;
1010
1011         BUG_ON(ret == 0);
1012
1013         ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
1014                                   BTRFS_DEV_ITEM_KEY);
1015         if (ret) {
1016                 *objectid = 1;
1017         } else {
1018                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1019                                       path->slots[0]);
1020                 *objectid = found_key.offset + 1;
1021         }
1022         ret = 0;
1023 error:
1024         btrfs_free_path(path);
1025         return ret;
1026 }
1027
1028 /*
1029  * the device information is stored in the chunk root
1030  * the btrfs_device struct should be fully filled in
1031  */
1032 int btrfs_add_device(struct btrfs_trans_handle *trans,
1033                      struct btrfs_root *root,
1034                      struct btrfs_device *device)
1035 {
1036         int ret;
1037         struct btrfs_path *path;
1038         struct btrfs_dev_item *dev_item;
1039         struct extent_buffer *leaf;
1040         struct btrfs_key key;
1041         unsigned long ptr;
1042
1043         root = root->fs_info->chunk_root;
1044
1045         path = btrfs_alloc_path();
1046         if (!path)
1047                 return -ENOMEM;
1048
1049         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1050         key.type = BTRFS_DEV_ITEM_KEY;
1051         key.offset = device->devid;
1052
1053         ret = btrfs_insert_empty_item(trans, root, path, &key,
1054                                       sizeof(*dev_item));
1055         if (ret)
1056                 goto out;
1057
1058         leaf = path->nodes[0];
1059         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1060
1061         btrfs_set_device_id(leaf, dev_item, device->devid);
1062         btrfs_set_device_generation(leaf, dev_item, 0);
1063         btrfs_set_device_type(leaf, dev_item, device->type);
1064         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1065         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1066         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1067         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
1068         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1069         btrfs_set_device_group(leaf, dev_item, 0);
1070         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1071         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1072         btrfs_set_device_start_offset(leaf, dev_item, 0);
1073
1074         ptr = (unsigned long)btrfs_device_uuid(dev_item);
1075         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1076         ptr = (unsigned long)btrfs_device_fsid(dev_item);
1077         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1078         btrfs_mark_buffer_dirty(leaf);
1079
1080         ret = 0;
1081 out:
1082         btrfs_free_path(path);
1083         return ret;
1084 }
1085
1086 static int btrfs_rm_dev_item(struct btrfs_root *root,
1087                              struct btrfs_device *device)
1088 {
1089         int ret;
1090         struct btrfs_path *path;
1091         struct btrfs_key key;
1092         struct btrfs_trans_handle *trans;
1093
1094         root = root->fs_info->chunk_root;
1095
1096         path = btrfs_alloc_path();
1097         if (!path)
1098                 return -ENOMEM;
1099
1100         trans = btrfs_start_transaction(root, 1);
1101         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1102         key.type = BTRFS_DEV_ITEM_KEY;
1103         key.offset = device->devid;
1104         lock_chunks(root);
1105
1106         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1107         if (ret < 0)
1108                 goto out;
1109
1110         if (ret > 0) {
1111                 ret = -ENOENT;
1112                 goto out;
1113         }
1114
1115         ret = btrfs_del_item(trans, root, path);
1116         if (ret)
1117                 goto out;
1118 out:
1119         btrfs_free_path(path);
1120         unlock_chunks(root);
1121         btrfs_commit_transaction(trans, root);
1122         return ret;
1123 }
1124
1125 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1126 {
1127         struct btrfs_device *device;
1128         struct btrfs_device *next_device;
1129         struct block_device *bdev;
1130         struct buffer_head *bh = NULL;
1131         struct btrfs_super_block *disk_super;
1132         u64 all_avail;
1133         u64 devid;
1134         u64 num_devices;
1135         u8 *dev_uuid;
1136         int ret = 0;
1137
1138         mutex_lock(&uuid_mutex);
1139         mutex_lock(&root->fs_info->volume_mutex);
1140
1141         all_avail = root->fs_info->avail_data_alloc_bits |
1142                 root->fs_info->avail_system_alloc_bits |
1143                 root->fs_info->avail_metadata_alloc_bits;
1144
1145         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) &&
1146             root->fs_info->fs_devices->num_devices <= 4) {
1147                 printk(KERN_ERR "btrfs: unable to go below four devices "
1148                        "on raid10\n");
1149                 ret = -EINVAL;
1150                 goto out;
1151         }
1152
1153         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) &&
1154             root->fs_info->fs_devices->num_devices <= 2) {
1155                 printk(KERN_ERR "btrfs: unable to go below two "
1156                        "devices on raid1\n");
1157                 ret = -EINVAL;
1158                 goto out;
1159         }
1160
1161         if (strcmp(device_path, "missing") == 0) {
1162                 struct list_head *devices;
1163                 struct btrfs_device *tmp;
1164
1165                 device = NULL;
1166                 devices = &root->fs_info->fs_devices->devices;
1167                 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1168                 list_for_each_entry(tmp, devices, dev_list) {
1169                         if (tmp->in_fs_metadata && !tmp->bdev) {
1170                                 device = tmp;
1171                                 break;
1172                         }
1173                 }
1174                 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1175                 bdev = NULL;
1176                 bh = NULL;
1177                 disk_super = NULL;
1178                 if (!device) {
1179                         printk(KERN_ERR "btrfs: no missing devices found to "
1180                                "remove\n");
1181                         goto out;
1182                 }
1183         } else {
1184                 bdev = open_bdev_exclusive(device_path, FMODE_READ,
1185                                       root->fs_info->bdev_holder);
1186                 if (IS_ERR(bdev)) {
1187                         ret = PTR_ERR(bdev);
1188                         goto out;
1189                 }
1190
1191                 set_blocksize(bdev, 4096);
1192                 bh = btrfs_read_dev_super(bdev);
1193                 if (!bh) {
1194                         ret = -EIO;
1195                         goto error_close;
1196                 }
1197                 disk_super = (struct btrfs_super_block *)bh->b_data;
1198                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1199                 dev_uuid = disk_super->dev_item.uuid;
1200                 device = btrfs_find_device(root, devid, dev_uuid,
1201                                            disk_super->fsid);
1202                 if (!device) {
1203                         ret = -ENOENT;
1204                         goto error_brelse;
1205                 }
1206         }
1207
1208         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1209                 printk(KERN_ERR "btrfs: unable to remove the only writeable "
1210                        "device\n");
1211                 ret = -EINVAL;
1212                 goto error_brelse;
1213         }
1214
1215         if (device->writeable) {
1216                 list_del_init(&device->dev_alloc_list);
1217                 root->fs_info->fs_devices->rw_devices--;
1218         }
1219
1220         ret = btrfs_shrink_device(device, 0);
1221         if (ret)
1222                 goto error_brelse;
1223
1224         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1225         if (ret)
1226                 goto error_brelse;
1227
1228         device->in_fs_metadata = 0;
1229
1230         /*
1231          * the device list mutex makes sure that we don't change
1232          * the device list while someone else is writing out all
1233          * the device supers.
1234          */
1235         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1236         list_del_init(&device->dev_list);
1237         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1238
1239         device->fs_devices->num_devices--;
1240
1241         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1242                                  struct btrfs_device, dev_list);
1243         if (device->bdev == root->fs_info->sb->s_bdev)
1244                 root->fs_info->sb->s_bdev = next_device->bdev;
1245         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1246                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1247
1248         if (device->bdev) {
1249                 close_bdev_exclusive(device->bdev, device->mode);
1250                 device->bdev = NULL;
1251                 device->fs_devices->open_devices--;
1252         }
1253
1254         num_devices = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
1255         btrfs_set_super_num_devices(&root->fs_info->super_copy, num_devices);
1256
1257         if (device->fs_devices->open_devices == 0) {
1258                 struct btrfs_fs_devices *fs_devices;
1259                 fs_devices = root->fs_info->fs_devices;
1260                 while (fs_devices) {
1261                         if (fs_devices->seed == device->fs_devices)
1262                                 break;
1263                         fs_devices = fs_devices->seed;
1264                 }
1265                 fs_devices->seed = device->fs_devices->seed;
1266                 device->fs_devices->seed = NULL;
1267                 __btrfs_close_devices(device->fs_devices);
1268                 free_fs_devices(device->fs_devices);
1269         }
1270
1271         /*
1272          * at this point, the device is zero sized.  We want to
1273          * remove it from the devices list and zero out the old super
1274          */
1275         if (device->writeable) {
1276                 /* make sure this device isn't detected as part of
1277                  * the FS anymore
1278                  */
1279                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1280                 set_buffer_dirty(bh);
1281                 sync_dirty_buffer(bh);
1282         }
1283
1284         kfree(device->name);
1285         kfree(device);
1286         ret = 0;
1287
1288 error_brelse:
1289         brelse(bh);
1290 error_close:
1291         if (bdev)
1292                 close_bdev_exclusive(bdev, FMODE_READ);
1293 out:
1294         mutex_unlock(&root->fs_info->volume_mutex);
1295         mutex_unlock(&uuid_mutex);
1296         return ret;
1297 }
1298
1299 /*
1300  * does all the dirty work required for changing file system's UUID.
1301  */
1302 static int btrfs_prepare_sprout(struct btrfs_trans_handle *trans,
1303                                 struct btrfs_root *root)
1304 {
1305         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
1306         struct btrfs_fs_devices *old_devices;
1307         struct btrfs_fs_devices *seed_devices;
1308         struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
1309         struct btrfs_device *device;
1310         u64 super_flags;
1311
1312         BUG_ON(!mutex_is_locked(&uuid_mutex));
1313         if (!fs_devices->seeding)
1314                 return -EINVAL;
1315
1316         seed_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
1317         if (!seed_devices)
1318                 return -ENOMEM;
1319
1320         old_devices = clone_fs_devices(fs_devices);
1321         if (IS_ERR(old_devices)) {
1322                 kfree(seed_devices);
1323                 return PTR_ERR(old_devices);
1324         }
1325
1326         list_add(&old_devices->list, &fs_uuids);
1327
1328         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
1329         seed_devices->opened = 1;
1330         INIT_LIST_HEAD(&seed_devices->devices);
1331         INIT_LIST_HEAD(&seed_devices->alloc_list);
1332         mutex_init(&seed_devices->device_list_mutex);
1333         list_splice_init(&fs_devices->devices, &seed_devices->devices);
1334         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
1335         list_for_each_entry(device, &seed_devices->devices, dev_list) {
1336                 device->fs_devices = seed_devices;
1337         }
1338
1339         fs_devices->seeding = 0;
1340         fs_devices->num_devices = 0;
1341         fs_devices->open_devices = 0;
1342         fs_devices->seed = seed_devices;
1343
1344         generate_random_uuid(fs_devices->fsid);
1345         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1346         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1347         super_flags = btrfs_super_flags(disk_super) &
1348                       ~BTRFS_SUPER_FLAG_SEEDING;
1349         btrfs_set_super_flags(disk_super, super_flags);
1350
1351         return 0;
1352 }
1353
1354 /*
1355  * strore the expected generation for seed devices in device items.
1356  */
1357 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
1358                                struct btrfs_root *root)
1359 {
1360         struct btrfs_path *path;
1361         struct extent_buffer *leaf;
1362         struct btrfs_dev_item *dev_item;
1363         struct btrfs_device *device;
1364         struct btrfs_key key;
1365         u8 fs_uuid[BTRFS_UUID_SIZE];
1366         u8 dev_uuid[BTRFS_UUID_SIZE];
1367         u64 devid;
1368         int ret;
1369
1370         path = btrfs_alloc_path();
1371         if (!path)
1372                 return -ENOMEM;
1373
1374         root = root->fs_info->chunk_root;
1375         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1376         key.offset = 0;
1377         key.type = BTRFS_DEV_ITEM_KEY;
1378
1379         while (1) {
1380                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1381                 if (ret < 0)
1382                         goto error;
1383
1384                 leaf = path->nodes[0];
1385 next_slot:
1386                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1387                         ret = btrfs_next_leaf(root, path);
1388                         if (ret > 0)
1389                                 break;
1390                         if (ret < 0)
1391                                 goto error;
1392                         leaf = path->nodes[0];
1393                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1394                         btrfs_release_path(root, path);
1395                         continue;
1396                 }
1397
1398                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1399                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
1400                     key.type != BTRFS_DEV_ITEM_KEY)
1401                         break;
1402
1403                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
1404                                           struct btrfs_dev_item);
1405                 devid = btrfs_device_id(leaf, dev_item);
1406                 read_extent_buffer(leaf, dev_uuid,
1407                                    (unsigned long)btrfs_device_uuid(dev_item),
1408                                    BTRFS_UUID_SIZE);
1409                 read_extent_buffer(leaf, fs_uuid,
1410                                    (unsigned long)btrfs_device_fsid(dev_item),
1411                                    BTRFS_UUID_SIZE);
1412                 device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
1413                 BUG_ON(!device);
1414
1415                 if (device->fs_devices->seeding) {
1416                         btrfs_set_device_generation(leaf, dev_item,
1417                                                     device->generation);
1418                         btrfs_mark_buffer_dirty(leaf);
1419                 }
1420
1421                 path->slots[0]++;
1422                 goto next_slot;
1423         }
1424         ret = 0;
1425 error:
1426         btrfs_free_path(path);
1427         return ret;
1428 }
1429
1430 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
1431 {
1432         struct btrfs_trans_handle *trans;
1433         struct btrfs_device *device;
1434         struct block_device *bdev;
1435         struct list_head *devices;
1436         struct super_block *sb = root->fs_info->sb;
1437         u64 total_bytes;
1438         int seeding_dev = 0;
1439         int ret = 0;
1440
1441         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
1442                 return -EINVAL;
1443
1444         bdev = open_bdev_exclusive(device_path, 0, root->fs_info->bdev_holder);
1445         if (IS_ERR(bdev))
1446                 return PTR_ERR(bdev);
1447
1448         if (root->fs_info->fs_devices->seeding) {
1449                 seeding_dev = 1;
1450                 down_write(&sb->s_umount);
1451                 mutex_lock(&uuid_mutex);
1452         }
1453
1454         filemap_write_and_wait(bdev->bd_inode->i_mapping);
1455         mutex_lock(&root->fs_info->volume_mutex);
1456
1457         devices = &root->fs_info->fs_devices->devices;
1458         /*
1459          * we have the volume lock, so we don't need the extra
1460          * device list mutex while reading the list here.
1461          */
1462         list_for_each_entry(device, devices, dev_list) {
1463                 if (device->bdev == bdev) {
1464                         ret = -EEXIST;
1465                         goto error;
1466                 }
1467         }
1468
1469         device = kzalloc(sizeof(*device), GFP_NOFS);
1470         if (!device) {
1471                 /* we can safely leave the fs_devices entry around */
1472                 ret = -ENOMEM;
1473                 goto error;
1474         }
1475
1476         device->name = kstrdup(device_path, GFP_NOFS);
1477         if (!device->name) {
1478                 kfree(device);
1479                 ret = -ENOMEM;
1480                 goto error;
1481         }
1482
1483         ret = find_next_devid(root, &device->devid);
1484         if (ret) {
1485                 kfree(device);
1486                 goto error;
1487         }
1488
1489         trans = btrfs_start_transaction(root, 1);
1490         lock_chunks(root);
1491
1492         device->barriers = 1;
1493         device->writeable = 1;
1494         device->work.func = pending_bios_fn;
1495         generate_random_uuid(device->uuid);
1496         spin_lock_init(&device->io_lock);
1497         device->generation = trans->transid;
1498         device->io_width = root->sectorsize;
1499         device->io_align = root->sectorsize;
1500         device->sector_size = root->sectorsize;
1501         device->total_bytes = i_size_read(bdev->bd_inode);
1502         device->disk_total_bytes = device->total_bytes;
1503         device->dev_root = root->fs_info->dev_root;
1504         device->bdev = bdev;
1505         device->in_fs_metadata = 1;
1506         device->mode = 0;
1507         set_blocksize(device->bdev, 4096);
1508
1509         if (seeding_dev) {
1510                 sb->s_flags &= ~MS_RDONLY;
1511                 ret = btrfs_prepare_sprout(trans, root);
1512                 BUG_ON(ret);
1513         }
1514
1515         device->fs_devices = root->fs_info->fs_devices;
1516
1517         /*
1518          * we don't want write_supers to jump in here with our device
1519          * half setup
1520          */
1521         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1522         list_add(&device->dev_list, &root->fs_info->fs_devices->devices);
1523         list_add(&device->dev_alloc_list,
1524                  &root->fs_info->fs_devices->alloc_list);
1525         root->fs_info->fs_devices->num_devices++;
1526         root->fs_info->fs_devices->open_devices++;
1527         root->fs_info->fs_devices->rw_devices++;
1528         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
1529
1530         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
1531                 root->fs_info->fs_devices->rotating = 1;
1532
1533         total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
1534         btrfs_set_super_total_bytes(&root->fs_info->super_copy,
1535                                     total_bytes + device->total_bytes);
1536
1537         total_bytes = btrfs_super_num_devices(&root->fs_info->super_copy);
1538         btrfs_set_super_num_devices(&root->fs_info->super_copy,
1539                                     total_bytes + 1);
1540         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1541
1542         if (seeding_dev) {
1543                 ret = init_first_rw_device(trans, root, device);
1544                 BUG_ON(ret);
1545                 ret = btrfs_finish_sprout(trans, root);
1546                 BUG_ON(ret);
1547         } else {
1548                 ret = btrfs_add_device(trans, root, device);
1549         }
1550
1551         /*
1552          * we've got more storage, clear any full flags on the space
1553          * infos
1554          */
1555         btrfs_clear_space_info_full(root->fs_info);
1556
1557         unlock_chunks(root);
1558         btrfs_commit_transaction(trans, root);
1559
1560         if (seeding_dev) {
1561                 mutex_unlock(&uuid_mutex);
1562                 up_write(&sb->s_umount);
1563
1564                 ret = btrfs_relocate_sys_chunks(root);
1565                 BUG_ON(ret);
1566         }
1567 out:
1568         mutex_unlock(&root->fs_info->volume_mutex);
1569         return ret;
1570 error:
1571         close_bdev_exclusive(bdev, 0);
1572         if (seeding_dev) {
1573                 mutex_unlock(&uuid_mutex);
1574                 up_write(&sb->s_umount);
1575         }
1576         goto out;
1577 }
1578
1579 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
1580                                         struct btrfs_device *device)
1581 {
1582         int ret;
1583         struct btrfs_path *path;
1584         struct btrfs_root *root;
1585         struct btrfs_dev_item *dev_item;
1586         struct extent_buffer *leaf;
1587         struct btrfs_key key;
1588
1589         root = device->dev_root->fs_info->chunk_root;
1590
1591         path = btrfs_alloc_path();
1592         if (!path)
1593                 return -ENOMEM;
1594
1595         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1596         key.type = BTRFS_DEV_ITEM_KEY;
1597         key.offset = device->devid;
1598
1599         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1600         if (ret < 0)
1601                 goto out;
1602
1603         if (ret > 0) {
1604                 ret = -ENOENT;
1605                 goto out;
1606         }
1607
1608         leaf = path->nodes[0];
1609         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1610
1611         btrfs_set_device_id(leaf, dev_item, device->devid);
1612         btrfs_set_device_type(leaf, dev_item, device->type);
1613         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1614         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1615         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1616         btrfs_set_device_total_bytes(leaf, dev_item, device->disk_total_bytes);
1617         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1618         btrfs_mark_buffer_dirty(leaf);
1619
1620 out:
1621         btrfs_free_path(path);
1622         return ret;
1623 }
1624
1625 static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
1626                       struct btrfs_device *device, u64 new_size)
1627 {
1628         struct btrfs_super_block *super_copy =
1629                 &device->dev_root->fs_info->super_copy;
1630         u64 old_total = btrfs_super_total_bytes(super_copy);
1631         u64 diff = new_size - device->total_bytes;
1632
1633         if (!device->writeable)
1634                 return -EACCES;
1635         if (new_size <= device->total_bytes)
1636                 return -EINVAL;
1637
1638         btrfs_set_super_total_bytes(super_copy, old_total + diff);
1639         device->fs_devices->total_rw_bytes += diff;
1640
1641         device->total_bytes = new_size;
1642         device->disk_total_bytes = new_size;
1643         btrfs_clear_space_info_full(device->dev_root->fs_info);
1644
1645         return btrfs_update_device(trans, device);
1646 }
1647
1648 int btrfs_grow_device(struct btrfs_trans_handle *trans,
1649                       struct btrfs_device *device, u64 new_size)
1650 {
1651         int ret;
1652         lock_chunks(device->dev_root);
1653         ret = __btrfs_grow_device(trans, device, new_size);
1654         unlock_chunks(device->dev_root);
1655         return ret;
1656 }
1657
1658 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
1659                             struct btrfs_root *root,
1660                             u64 chunk_tree, u64 chunk_objectid,
1661                             u64 chunk_offset)
1662 {
1663         int ret;
1664         struct btrfs_path *path;
1665         struct btrfs_key key;
1666
1667         root = root->fs_info->chunk_root;
1668         path = btrfs_alloc_path();
1669         if (!path)
1670                 return -ENOMEM;
1671
1672         key.objectid = chunk_objectid;
1673         key.offset = chunk_offset;
1674         key.type = BTRFS_CHUNK_ITEM_KEY;
1675
1676         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1677         BUG_ON(ret);
1678
1679         ret = btrfs_del_item(trans, root, path);
1680         BUG_ON(ret);
1681
1682         btrfs_free_path(path);
1683         return 0;
1684 }
1685
1686 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
1687                         chunk_offset)
1688 {
1689         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
1690         struct btrfs_disk_key *disk_key;
1691         struct btrfs_chunk *chunk;
1692         u8 *ptr;
1693         int ret = 0;
1694         u32 num_stripes;
1695         u32 array_size;
1696         u32 len = 0;
1697         u32 cur;
1698         struct btrfs_key key;
1699
1700         array_size = btrfs_super_sys_array_size(super_copy);
1701
1702         ptr = super_copy->sys_chunk_array;
1703         cur = 0;
1704
1705         while (cur < array_size) {
1706                 disk_key = (struct btrfs_disk_key *)ptr;
1707                 btrfs_disk_key_to_cpu(&key, disk_key);
1708
1709                 len = sizeof(*disk_key);
1710
1711                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
1712                         chunk = (struct btrfs_chunk *)(ptr + len);
1713                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
1714                         len += btrfs_chunk_item_size(num_stripes);
1715                 } else {
1716                         ret = -EIO;
1717                         break;
1718                 }
1719                 if (key.objectid == chunk_objectid &&
1720                     key.offset == chunk_offset) {
1721                         memmove(ptr, ptr + len, array_size - (cur + len));
1722                         array_size -= len;
1723                         btrfs_set_super_sys_array_size(super_copy, array_size);
1724                 } else {
1725                         ptr += len;
1726                         cur += len;
1727                 }
1728         }
1729         return ret;
1730 }
1731
1732 static int btrfs_relocate_chunk(struct btrfs_root *root,
1733                          u64 chunk_tree, u64 chunk_objectid,
1734                          u64 chunk_offset)
1735 {
1736         struct extent_map_tree *em_tree;
1737         struct btrfs_root *extent_root;
1738         struct btrfs_trans_handle *trans;
1739         struct extent_map *em;
1740         struct map_lookup *map;
1741         int ret;
1742         int i;
1743
1744         root = root->fs_info->chunk_root;
1745         extent_root = root->fs_info->extent_root;
1746         em_tree = &root->fs_info->mapping_tree.map_tree;
1747
1748         ret = btrfs_can_relocate(extent_root, chunk_offset);
1749         if (ret)
1750                 return -ENOSPC;
1751
1752         /* step one, relocate all the extents inside this chunk */
1753         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
1754         BUG_ON(ret);
1755
1756         trans = btrfs_start_transaction(root, 1);
1757         BUG_ON(!trans);
1758
1759         lock_chunks(root);
1760
1761         /*
1762          * step two, delete the device extents and the
1763          * chunk tree entries
1764          */
1765         read_lock(&em_tree->lock);
1766         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
1767         read_unlock(&em_tree->lock);
1768
1769         BUG_ON(em->start > chunk_offset ||
1770                em->start + em->len < chunk_offset);
1771         map = (struct map_lookup *)em->bdev;
1772
1773         for (i = 0; i < map->num_stripes; i++) {
1774                 ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
1775                                             map->stripes[i].physical);
1776                 BUG_ON(ret);
1777
1778                 if (map->stripes[i].dev) {
1779                         ret = btrfs_update_device(trans, map->stripes[i].dev);
1780                         BUG_ON(ret);
1781                 }
1782         }
1783         ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
1784                                chunk_offset);
1785
1786         BUG_ON(ret);
1787
1788         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
1789                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
1790                 BUG_ON(ret);
1791         }
1792
1793         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
1794         BUG_ON(ret);
1795
1796         write_lock(&em_tree->lock);
1797         remove_extent_mapping(em_tree, em);
1798         write_unlock(&em_tree->lock);
1799
1800         kfree(map);
1801         em->bdev = NULL;
1802
1803         /* once for the tree */
1804         free_extent_map(em);
1805         /* once for us */
1806         free_extent_map(em);
1807
1808         unlock_chunks(root);
1809         btrfs_end_transaction(trans, root);
1810         return 0;
1811 }
1812
1813 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
1814 {
1815         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
1816         struct btrfs_path *path;
1817         struct extent_buffer *leaf;
1818         struct btrfs_chunk *chunk;
1819         struct btrfs_key key;
1820         struct btrfs_key found_key;
1821         u64 chunk_tree = chunk_root->root_key.objectid;
1822         u64 chunk_type;
1823         bool retried = false;
1824         int failed = 0;
1825         int ret;
1826
1827         path = btrfs_alloc_path();
1828         if (!path)
1829                 return -ENOMEM;
1830
1831 again:
1832         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
1833         key.offset = (u64)-1;
1834         key.type = BTRFS_CHUNK_ITEM_KEY;
1835
1836         while (1) {
1837                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
1838                 if (ret < 0)
1839                         goto error;
1840                 BUG_ON(ret == 0);
1841
1842                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
1843                                           key.type);
1844                 if (ret < 0)
1845                         goto error;
1846                 if (ret > 0)
1847                         break;
1848
1849                 leaf = path->nodes[0];
1850                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1851
1852                 chunk = btrfs_item_ptr(leaf, path->slots[0],
1853                                        struct btrfs_chunk);
1854                 chunk_type = btrfs_chunk_type(leaf, chunk);
1855                 btrfs_release_path(chunk_root, path);
1856
1857                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
1858                         ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
1859                                                    found_key.objectid,
1860                                                    found_key.offset);
1861                         if (ret == -ENOSPC)
1862                                 failed++;
1863                         else if (ret)
1864                                 BUG();
1865                 }
1866
1867                 if (found_key.offset == 0)
1868                         break;
1869                 key.offset = found_key.offset - 1;
1870         }
1871         ret = 0;
1872         if (failed && !retried) {
1873                 failed = 0;
1874                 retried = true;
1875                 goto again;
1876         } else if (failed && retried) {
1877                 WARN_ON(1);
1878                 ret = -ENOSPC;
1879         }
1880 error:
1881         btrfs_free_path(path);
1882         return ret;
1883 }
1884
1885 static u64 div_factor(u64 num, int factor)
1886 {
1887         if (factor == 10)
1888                 return num;
1889         num *= factor;
1890         do_div(num, 10);
1891         return num;
1892 }
1893
1894 int btrfs_balance(struct btrfs_root *dev_root)
1895 {
1896         int ret;
1897         struct list_head *devices = &dev_root->fs_info->fs_devices->devices;
1898         struct btrfs_device *device;
1899         u64 old_size;
1900         u64 size_to_free;
1901         struct btrfs_path *path;
1902         struct btrfs_key key;
1903         struct btrfs_chunk *chunk;
1904         struct btrfs_root *chunk_root = dev_root->fs_info->chunk_root;
1905         struct btrfs_trans_handle *trans;
1906         struct btrfs_key found_key;
1907
1908         if (dev_root->fs_info->sb->s_flags & MS_RDONLY)
1909                 return -EROFS;
1910
1911         mutex_lock(&dev_root->fs_info->volume_mutex);
1912         dev_root = dev_root->fs_info->dev_root;
1913
1914         /* step one make some room on all the devices */
1915         list_for_each_entry(device, devices, dev_list) {
1916                 old_size = device->total_bytes;
1917                 size_to_free = div_factor(old_size, 1);
1918                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
1919                 if (!device->writeable ||
1920                     device->total_bytes - device->bytes_used > size_to_free)
1921                         continue;
1922
1923                 ret = btrfs_shrink_device(device, old_size - size_to_free);
1924                 if (ret == -ENOSPC)
1925                         break;
1926                 BUG_ON(ret);
1927
1928                 trans = btrfs_start_transaction(dev_root, 1);
1929                 BUG_ON(!trans);
1930
1931                 ret = btrfs_grow_device(trans, device, old_size);
1932                 BUG_ON(ret);
1933
1934                 btrfs_end_transaction(trans, dev_root);
1935         }
1936
1937         /* step two, relocate all the chunks */
1938         path = btrfs_alloc_path();
1939         BUG_ON(!path);
1940
1941         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
1942         key.offset = (u64)-1;
1943         key.type = BTRFS_CHUNK_ITEM_KEY;
1944
1945         while (1) {
1946                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
1947                 if (ret < 0)
1948                         goto error;
1949
1950                 /*
1951                  * this shouldn't happen, it means the last relocate
1952                  * failed
1953                  */
1954                 if (ret == 0)
1955                         break;
1956
1957                 ret = btrfs_previous_item(chunk_root, path, 0,
1958                                           BTRFS_CHUNK_ITEM_KEY);
1959                 if (ret)
1960                         break;
1961
1962                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1963                                       path->slots[0]);
1964                 if (found_key.objectid != key.objectid)
1965                         break;
1966
1967                 chunk = btrfs_item_ptr(path->nodes[0],
1968                                        path->slots[0],
1969                                        struct btrfs_chunk);
1970                 /* chunk zero is special */
1971                 if (found_key.offset == 0)
1972                         break;
1973
1974                 btrfs_release_path(chunk_root, path);
1975                 ret = btrfs_relocate_chunk(chunk_root,
1976                                            chunk_root->root_key.objectid,
1977                                            found_key.objectid,
1978                                            found_key.offset);
1979                 BUG_ON(ret && ret != -ENOSPC);
1980                 key.offset = found_key.offset - 1;
1981         }
1982         ret = 0;
1983 error:
1984         btrfs_free_path(path);
1985         mutex_unlock(&dev_root->fs_info->volume_mutex);
1986         return ret;
1987 }
1988
1989 /*
1990  * shrinking a device means finding all of the device extents past
1991  * the new size, and then following the back refs to the chunks.
1992  * The chunk relocation code actually frees the device extent
1993  */
1994 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
1995 {
1996         struct btrfs_trans_handle *trans;
1997         struct btrfs_root *root = device->dev_root;
1998         struct btrfs_dev_extent *dev_extent = NULL;
1999         struct btrfs_path *path;
2000         u64 length;
2001         u64 chunk_tree;
2002         u64 chunk_objectid;
2003         u64 chunk_offset;
2004         int ret;
2005         int slot;
2006         int failed = 0;
2007         bool retried = false;
2008         struct extent_buffer *l;
2009         struct btrfs_key key;
2010         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
2011         u64 old_total = btrfs_super_total_bytes(super_copy);
2012         u64 old_size = device->total_bytes;
2013         u64 diff = device->total_bytes - new_size;
2014
2015         if (new_size >= device->total_bytes)
2016                 return -EINVAL;
2017
2018         path = btrfs_alloc_path();
2019         if (!path)
2020                 return -ENOMEM;
2021
2022         path->reada = 2;
2023
2024         lock_chunks(root);
2025
2026         device->total_bytes = new_size;
2027         if (device->writeable)
2028                 device->fs_devices->total_rw_bytes -= diff;
2029         unlock_chunks(root);
2030
2031 again:
2032         key.objectid = device->devid;
2033         key.offset = (u64)-1;
2034         key.type = BTRFS_DEV_EXTENT_KEY;
2035
2036         while (1) {
2037                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2038                 if (ret < 0)
2039                         goto done;
2040
2041                 ret = btrfs_previous_item(root, path, 0, key.type);
2042                 if (ret < 0)
2043                         goto done;
2044                 if (ret) {
2045                         ret = 0;
2046                         btrfs_release_path(root, path);
2047                         break;
2048                 }
2049
2050                 l = path->nodes[0];
2051                 slot = path->slots[0];
2052                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
2053
2054                 if (key.objectid != device->devid) {
2055                         btrfs_release_path(root, path);
2056                         break;
2057                 }
2058
2059                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
2060                 length = btrfs_dev_extent_length(l, dev_extent);
2061
2062                 if (key.offset + length <= new_size) {
2063                         btrfs_release_path(root, path);
2064                         break;
2065                 }
2066
2067                 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
2068                 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
2069                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
2070                 btrfs_release_path(root, path);
2071
2072                 ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
2073                                            chunk_offset);
2074                 if (ret && ret != -ENOSPC)
2075                         goto done;
2076                 if (ret == -ENOSPC)
2077                         failed++;
2078                 key.offset -= 1;
2079         }
2080
2081         if (failed && !retried) {
2082                 failed = 0;
2083                 retried = true;
2084                 goto again;
2085         } else if (failed && retried) {
2086                 ret = -ENOSPC;
2087                 lock_chunks(root);
2088
2089                 device->total_bytes = old_size;
2090                 if (device->writeable)
2091                         device->fs_devices->total_rw_bytes += diff;
2092                 unlock_chunks(root);
2093                 goto done;
2094         }
2095
2096         /* Shrinking succeeded, else we would be at "done". */
2097         trans = btrfs_start_transaction(root, 1);
2098         if (!trans) {
2099                 ret = -ENOMEM;
2100                 goto done;
2101         }
2102         lock_chunks(root);
2103
2104         device->disk_total_bytes = new_size;
2105         /* Now btrfs_update_device() will change the on-disk size. */
2106         ret = btrfs_update_device(trans, device);
2107         if (ret) {
2108                 unlock_chunks(root);
2109                 btrfs_end_transaction(trans, root);
2110                 goto done;
2111         }
2112         WARN_ON(diff > old_total);
2113         btrfs_set_super_total_bytes(super_copy, old_total - diff);
2114         unlock_chunks(root);
2115         btrfs_end_transaction(trans, root);
2116 done:
2117         btrfs_free_path(path);
2118         return ret;
2119 }
2120
2121 static int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
2122                            struct btrfs_root *root,
2123                            struct btrfs_key *key,
2124                            struct btrfs_chunk *chunk, int item_size)
2125 {
2126         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
2127         struct btrfs_disk_key disk_key;
2128         u32 array_size;
2129         u8 *ptr;
2130
2131         array_size = btrfs_super_sys_array_size(super_copy);
2132         if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
2133                 return -EFBIG;
2134
2135         ptr = super_copy->sys_chunk_array + array_size;
2136         btrfs_cpu_key_to_disk(&disk_key, key);
2137         memcpy(ptr, &disk_key, sizeof(disk_key));
2138         ptr += sizeof(disk_key);
2139         memcpy(ptr, chunk, item_size);
2140         item_size += sizeof(disk_key);
2141         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
2142         return 0;
2143 }
2144
2145 static noinline u64 chunk_bytes_by_type(u64 type, u64 calc_size,
2146                                         int num_stripes, int sub_stripes)
2147 {
2148         if (type & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_DUP))
2149                 return calc_size;
2150         else if (type & BTRFS_BLOCK_GROUP_RAID10)
2151                 return calc_size * (num_stripes / sub_stripes);
2152         else
2153                 return calc_size * num_stripes;
2154 }
2155
2156 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
2157                                struct btrfs_root *extent_root,
2158                                struct map_lookup **map_ret,
2159                                u64 *num_bytes, u64 *stripe_size,
2160                                u64 start, u64 type)
2161 {
2162         struct btrfs_fs_info *info = extent_root->fs_info;
2163         struct btrfs_device *device = NULL;
2164         struct btrfs_fs_devices *fs_devices = info->fs_devices;
2165         struct list_head *cur;
2166         struct map_lookup *map = NULL;
2167         struct extent_map_tree *em_tree;
2168         struct extent_map *em;
2169         struct list_head private_devs;
2170         int min_stripe_size = 1 * 1024 * 1024;
2171         u64 calc_size = 1024 * 1024 * 1024;
2172         u64 max_chunk_size = calc_size;
2173         u64 min_free;
2174         u64 avail;
2175         u64 max_avail = 0;
2176         u64 dev_offset;
2177         int num_stripes = 1;
2178         int min_stripes = 1;
2179         int sub_stripes = 0;
2180         int looped = 0;
2181         int ret;
2182         int index;
2183         int stripe_len = 64 * 1024;
2184
2185         if ((type & BTRFS_BLOCK_GROUP_RAID1) &&
2186             (type & BTRFS_BLOCK_GROUP_DUP)) {
2187                 WARN_ON(1);
2188                 type &= ~BTRFS_BLOCK_GROUP_DUP;
2189         }
2190         if (list_empty(&fs_devices->alloc_list))
2191                 return -ENOSPC;
2192
2193         if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
2194                 num_stripes = fs_devices->rw_devices;
2195                 min_stripes = 2;
2196         }
2197         if (type & (BTRFS_BLOCK_GROUP_DUP)) {
2198                 num_stripes = 2;
2199                 min_stripes = 2;
2200         }
2201         if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
2202                 if (fs_devices->rw_devices < 2)
2203                         return -ENOSPC;
2204                 num_stripes = 2;
2205                 min_stripes = 2;
2206         }
2207         if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
2208                 num_stripes = fs_devices->rw_devices;
2209                 if (num_stripes < 4)
2210                         return -ENOSPC;
2211                 num_stripes &= ~(u32)1;
2212                 sub_stripes = 2;
2213                 min_stripes = 4;
2214         }
2215
2216         if (type & BTRFS_BLOCK_GROUP_DATA) {
2217                 max_chunk_size = 10 * calc_size;
2218                 min_stripe_size = 64 * 1024 * 1024;
2219         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
2220                 max_chunk_size = 256 * 1024 * 1024;
2221                 min_stripe_size = 32 * 1024 * 1024;
2222         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
2223                 calc_size = 8 * 1024 * 1024;
2224                 max_chunk_size = calc_size * 2;
2225                 min_stripe_size = 1 * 1024 * 1024;
2226         }
2227
2228         /* we don't want a chunk larger than 10% of writeable space */
2229         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
2230                              max_chunk_size);
2231
2232 again:
2233         max_avail = 0;
2234         if (!map || map->num_stripes != num_stripes) {
2235                 kfree(map);
2236                 map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
2237                 if (!map)
2238                         return -ENOMEM;
2239                 map->num_stripes = num_stripes;
2240         }
2241
2242         if (calc_size * num_stripes > max_chunk_size) {
2243                 calc_size = max_chunk_size;
2244                 do_div(calc_size, num_stripes);
2245                 do_div(calc_size, stripe_len);
2246                 calc_size *= stripe_len;
2247         }
2248
2249         /* we don't want tiny stripes */
2250         if (!looped)
2251                 calc_size = max_t(u64, min_stripe_size, calc_size);
2252
2253         /*
2254          * we're about to do_div by the stripe_len so lets make sure
2255          * we end up with something bigger than a stripe
2256          */
2257         calc_size = max_t(u64, calc_size, stripe_len * 4);
2258
2259         do_div(calc_size, stripe_len);
2260         calc_size *= stripe_len;
2261
2262         cur = fs_devices->alloc_list.next;
2263         index = 0;
2264
2265         if (type & BTRFS_BLOCK_GROUP_DUP)
2266                 min_free = calc_size * 2;
2267         else
2268                 min_free = calc_size;
2269
2270         /*
2271          * we add 1MB because we never use the first 1MB of the device, unless
2272          * we've looped, then we are likely allocating the maximum amount of
2273          * space left already
2274          */
2275         if (!looped)
2276                 min_free += 1024 * 1024;
2277
2278         INIT_LIST_HEAD(&private_devs);
2279         while (index < num_stripes) {
2280                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
2281                 BUG_ON(!device->writeable);
2282                 if (device->total_bytes > device->bytes_used)
2283                         avail = device->total_bytes - device->bytes_used;
2284                 else
2285                         avail = 0;
2286                 cur = cur->next;
2287
2288                 if (device->in_fs_metadata && avail >= min_free) {
2289                         ret = find_free_dev_extent(trans, device,
2290                                                    min_free, &dev_offset,
2291                                                    &max_avail);
2292                         if (ret == 0) {
2293                                 list_move_tail(&device->dev_alloc_list,
2294                                                &private_devs);
2295                                 map->stripes[index].dev = device;
2296                                 map->stripes[index].physical = dev_offset;
2297                                 index++;
2298                                 if (type & BTRFS_BLOCK_GROUP_DUP) {
2299                                         map->stripes[index].dev = device;
2300                                         map->stripes[index].physical =
2301                                                 dev_offset + calc_size;
2302                                         index++;
2303                                 }
2304                         }
2305                 } else if (device->in_fs_metadata && avail > max_avail)
2306                         max_avail = avail;
2307                 if (cur == &fs_devices->alloc_list)
2308                         break;
2309         }
2310         list_splice(&private_devs, &fs_devices->alloc_list);
2311         if (index < num_stripes) {
2312                 if (index >= min_stripes) {
2313                         num_stripes = index;
2314                         if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
2315                                 num_stripes /= sub_stripes;
2316                                 num_stripes *= sub_stripes;
2317                         }
2318                         looped = 1;
2319                         goto again;
2320                 }
2321                 if (!looped && max_avail > 0) {
2322                         looped = 1;
2323                         calc_size = max_avail;
2324                         goto again;
2325                 }
2326                 kfree(map);
2327                 return -ENOSPC;
2328         }
2329         map->sector_size = extent_root->sectorsize;
2330         map->stripe_len = stripe_len;
2331         map->io_align = stripe_len;
2332         map->io_width = stripe_len;
2333         map->type = type;
2334         map->num_stripes = num_stripes;
2335         map->sub_stripes = sub_stripes;
2336
2337         *map_ret = map;
2338         *stripe_size = calc_size;
2339         *num_bytes = chunk_bytes_by_type(type, calc_size,
2340                                          num_stripes, sub_stripes);
2341
2342         em = alloc_extent_map(GFP_NOFS);
2343         if (!em) {
2344                 kfree(map);
2345                 return -ENOMEM;
2346         }
2347         em->bdev = (struct block_device *)map;
2348         em->start = start;
2349         em->len = *num_bytes;
2350         em->block_start = 0;
2351         em->block_len = em->len;
2352
2353         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
2354         write_lock(&em_tree->lock);
2355         ret = add_extent_mapping(em_tree, em);
2356         write_unlock(&em_tree->lock);
2357         BUG_ON(ret);
2358         free_extent_map(em);
2359
2360         ret = btrfs_make_block_group(trans, extent_root, 0, type,
2361                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2362                                      start, *num_bytes);
2363         BUG_ON(ret);
2364
2365         index = 0;
2366         while (index < map->num_stripes) {
2367                 device = map->stripes[index].dev;
2368                 dev_offset = map->stripes[index].physical;
2369
2370                 ret = btrfs_alloc_dev_extent(trans, device,
2371                                 info->chunk_root->root_key.objectid,
2372                                 BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2373                                 start, dev_offset, calc_size);
2374                 BUG_ON(ret);
2375                 index++;
2376         }
2377
2378         return 0;
2379 }
2380
2381 static int __finish_chunk_alloc(struct btrfs_trans_handle *trans,
2382                                 struct btrfs_root *extent_root,
2383                                 struct map_lookup *map, u64 chunk_offset,
2384                                 u64 chunk_size, u64 stripe_size)
2385 {
2386         u64 dev_offset;
2387         struct btrfs_key key;
2388         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
2389         struct btrfs_device *device;
2390         struct btrfs_chunk *chunk;
2391         struct btrfs_stripe *stripe;
2392         size_t item_size = btrfs_chunk_item_size(map->num_stripes);
2393         int index = 0;
2394         int ret;
2395
2396         chunk = kzalloc(item_size, GFP_NOFS);
2397         if (!chunk)
2398                 return -ENOMEM;
2399
2400         index = 0;
2401         while (index < map->num_stripes) {
2402                 device = map->stripes[index].dev;
2403                 device->bytes_used += stripe_size;
2404                 ret = btrfs_update_device(trans, device);
2405                 BUG_ON(ret);
2406                 index++;
2407         }
2408
2409         index = 0;
2410         stripe = &chunk->stripe;
2411         while (index < map->num_stripes) {
2412                 device = map->stripes[index].dev;
2413                 dev_offset = map->stripes[index].physical;
2414
2415                 btrfs_set_stack_stripe_devid(stripe, device->devid);
2416                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
2417                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
2418                 stripe++;
2419                 index++;
2420         }
2421
2422         btrfs_set_stack_chunk_length(chunk, chunk_size);
2423         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
2424         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
2425         btrfs_set_stack_chunk_type(chunk, map->type);
2426         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
2427         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
2428         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
2429         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
2430         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
2431
2432         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2433         key.type = BTRFS_CHUNK_ITEM_KEY;
2434         key.offset = chunk_offset;
2435
2436         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
2437         BUG_ON(ret);
2438
2439         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2440                 ret = btrfs_add_system_chunk(trans, chunk_root, &key, chunk,
2441                                              item_size);
2442                 BUG_ON(ret);
2443         }
2444         kfree(chunk);
2445         return 0;
2446 }
2447
2448 /*
2449  * Chunk allocation falls into two parts. The first part does works
2450  * that make the new allocated chunk useable, but not do any operation
2451  * that modifies the chunk tree. The second part does the works that
2452  * require modifying the chunk tree. This division is important for the
2453  * bootstrap process of adding storage to a seed btrfs.
2454  */
2455 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
2456                       struct btrfs_root *extent_root, u64 type)
2457 {
2458         u64 chunk_offset;
2459         u64 chunk_size;
2460         u64 stripe_size;
2461         struct map_lookup *map;
2462         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
2463         int ret;
2464
2465         ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2466                               &chunk_offset);
2467         if (ret)
2468                 return ret;
2469
2470         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
2471                                   &stripe_size, chunk_offset, type);
2472         if (ret)
2473                 return ret;
2474
2475         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
2476                                    chunk_size, stripe_size);
2477         BUG_ON(ret);
2478         return 0;
2479 }
2480
2481 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
2482                                          struct btrfs_root *root,
2483                                          struct btrfs_device *device)
2484 {
2485         u64 chunk_offset;
2486         u64 sys_chunk_offset;
2487         u64 chunk_size;
2488         u64 sys_chunk_size;
2489         u64 stripe_size;
2490         u64 sys_stripe_size;
2491         u64 alloc_profile;
2492         struct map_lookup *map;
2493         struct map_lookup *sys_map;
2494         struct btrfs_fs_info *fs_info = root->fs_info;
2495         struct btrfs_root *extent_root = fs_info->extent_root;
2496         int ret;
2497
2498         ret = find_next_chunk(fs_info->chunk_root,
2499                               BTRFS_FIRST_CHUNK_TREE_OBJECTID, &chunk_offset);
2500         BUG_ON(ret);
2501
2502         alloc_profile = BTRFS_BLOCK_GROUP_METADATA |
2503                         (fs_info->metadata_alloc_profile &
2504                          fs_info->avail_metadata_alloc_bits);
2505         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
2506
2507         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
2508                                   &stripe_size, chunk_offset, alloc_profile);
2509         BUG_ON(ret);
2510
2511         sys_chunk_offset = chunk_offset + chunk_size;
2512
2513         alloc_profile = BTRFS_BLOCK_GROUP_SYSTEM |
2514                         (fs_info->system_alloc_profile &
2515                          fs_info->avail_system_alloc_bits);
2516         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
2517
2518         ret = __btrfs_alloc_chunk(trans, extent_root, &sys_map,
2519                                   &sys_chunk_size, &sys_stripe_size,
2520                                   sys_chunk_offset, alloc_profile);
2521         BUG_ON(ret);
2522
2523         ret = btrfs_add_device(trans, fs_info->chunk_root, device);
2524         BUG_ON(ret);
2525
2526         /*
2527          * Modifying chunk tree needs allocating new blocks from both
2528          * system block group and metadata block group. So we only can
2529          * do operations require modifying the chunk tree after both
2530          * block groups were created.
2531          */
2532         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
2533                                    chunk_size, stripe_size);
2534         BUG_ON(ret);
2535
2536         ret = __finish_chunk_alloc(trans, extent_root, sys_map,
2537                                    sys_chunk_offset, sys_chunk_size,
2538                                    sys_stripe_size);
2539         BUG_ON(ret);
2540         return 0;
2541 }
2542
2543 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
2544 {
2545         struct extent_map *em;
2546         struct map_lookup *map;
2547         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
2548         int readonly = 0;
2549         int i;
2550
2551         read_lock(&map_tree->map_tree.lock);
2552         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
2553         read_unlock(&map_tree->map_tree.lock);
2554         if (!em)
2555                 return 1;
2556
2557         if (btrfs_test_opt(root, DEGRADED)) {
2558                 free_extent_map(em);
2559                 return 0;
2560         }
2561
2562         map = (struct map_lookup *)em->bdev;
2563         for (i = 0; i < map->num_stripes; i++) {
2564                 if (!map->stripes[i].dev->writeable) {
2565                         readonly = 1;
2566                         break;
2567                 }
2568         }
2569         free_extent_map(em);
2570         return readonly;
2571 }
2572
2573 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
2574 {
2575         extent_map_tree_init(&tree->map_tree, GFP_NOFS);
2576 }
2577
2578 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
2579 {
2580         struct extent_map *em;
2581
2582         while (1) {
2583                 write_lock(&tree->map_tree.lock);
2584                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
2585                 if (em)
2586                         remove_extent_mapping(&tree->map_tree, em);
2587                 write_unlock(&tree->map_tree.lock);
2588                 if (!em)
2589                         break;
2590                 kfree(em->bdev);
2591                 /* once for us */
2592                 free_extent_map(em);
2593                 /* once for the tree */
2594                 free_extent_map(em);
2595         }
2596 }
2597
2598 int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
2599 {
2600         struct extent_map *em;
2601         struct map_lookup *map;
2602         struct extent_map_tree *em_tree = &map_tree->map_tree;
2603         int ret;
2604
2605         read_lock(&em_tree->lock);
2606         em = lookup_extent_mapping(em_tree, logical, len);
2607         read_unlock(&em_tree->lock);
2608         BUG_ON(!em);
2609
2610         BUG_ON(em->start > logical || em->start + em->len < logical);
2611         map = (struct map_lookup *)em->bdev;
2612         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
2613                 ret = map->num_stripes;
2614         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
2615                 ret = map->sub_stripes;
2616         else
2617                 ret = 1;
2618         free_extent_map(em);
2619         return ret;
2620 }
2621
2622 static int find_live_mirror(struct map_lookup *map, int first, int num,
2623                             int optimal)
2624 {
2625         int i;
2626         if (map->stripes[optimal].dev->bdev)
2627                 return optimal;
2628         for (i = first; i < first + num; i++) {
2629                 if (map->stripes[i].dev->bdev)
2630                         return i;
2631         }
2632         /* we couldn't find one that doesn't fail.  Just return something
2633          * and the io error handling code will clean up eventually
2634          */
2635         return optimal;
2636 }
2637
2638 static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
2639                              u64 logical, u64 *length,
2640                              struct btrfs_multi_bio **multi_ret,
2641                              int mirror_num, struct page *unplug_page)
2642 {
2643         struct extent_map *em;
2644         struct map_lookup *map;
2645         struct extent_map_tree *em_tree = &map_tree->map_tree;
2646         u64 offset;
2647         u64 stripe_offset;
2648         u64 stripe_nr;
2649         int stripes_allocated = 8;
2650         int stripes_required = 1;
2651         int stripe_index;
2652         int i;
2653         int num_stripes;
2654         int max_errors = 0;
2655         struct btrfs_multi_bio *multi = NULL;
2656
2657         if (multi_ret && !(rw & (1 << BIO_RW)))
2658                 stripes_allocated = 1;
2659 again:
2660         if (multi_ret) {
2661                 multi = kzalloc(btrfs_multi_bio_size(stripes_allocated),
2662                                 GFP_NOFS);
2663                 if (!multi)
2664                         return -ENOMEM;
2665
2666                 atomic_set(&multi->error, 0);
2667         }
2668
2669         read_lock(&em_tree->lock);
2670         em = lookup_extent_mapping(em_tree, logical, *length);
2671         read_unlock(&em_tree->lock);
2672
2673         if (!em && unplug_page) {
2674                 kfree(multi);
2675                 return 0;
2676         }
2677
2678         if (!em) {
2679                 printk(KERN_CRIT "unable to find logical %llu len %llu\n",
2680                        (unsigned long long)logical,
2681                        (unsigned long long)*length);
2682                 BUG();
2683         }
2684
2685         BUG_ON(em->start > logical || em->start + em->len < logical);
2686         map = (struct map_lookup *)em->bdev;
2687         offset = logical - em->start;
2688
2689         if (mirror_num > map->num_stripes)
2690                 mirror_num = 0;
2691
2692         /* if our multi bio struct is too small, back off and try again */
2693         if (rw & (1 << BIO_RW)) {
2694                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
2695                                  BTRFS_BLOCK_GROUP_DUP)) {
2696                         stripes_required = map->num_stripes;
2697                         max_errors = 1;
2698                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
2699                         stripes_required = map->sub_stripes;
2700                         max_errors = 1;
2701                 }
2702         }
2703         if (multi_ret && (rw & (1 << BIO_RW)) &&
2704             stripes_allocated < stripes_required) {
2705                 stripes_allocated = map->num_stripes;
2706                 free_extent_map(em);
2707                 kfree(multi);
2708                 goto again;
2709         }
2710         stripe_nr = offset;
2711         /*
2712          * stripe_nr counts the total number of stripes we have to stride
2713          * to get to this block
2714          */
2715         do_div(stripe_nr, map->stripe_len);
2716
2717         stripe_offset = stripe_nr * map->stripe_len;
2718         BUG_ON(offset < stripe_offset);
2719
2720         /* stripe_offset is the offset of this block in its stripe*/
2721         stripe_offset = offset - stripe_offset;
2722
2723         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
2724                          BTRFS_BLOCK_GROUP_RAID10 |
2725                          BTRFS_BLOCK_GROUP_DUP)) {
2726                 /* we limit the length of each bio to what fits in a stripe */
2727                 *length = min_t(u64, em->len - offset,
2728                               map->stripe_len - stripe_offset);
2729         } else {
2730                 *length = em->len - offset;
2731         }
2732
2733         if (!multi_ret && !unplug_page)
2734                 goto out;
2735
2736         num_stripes = 1;
2737         stripe_index = 0;
2738         if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
2739                 if (unplug_page || (rw & (1 << BIO_RW)))
2740                         num_stripes = map->num_stripes;
2741                 else if (mirror_num)
2742                         stripe_index = mirror_num - 1;
2743                 else {
2744                         stripe_index = find_live_mirror(map, 0,
2745                                             map->num_stripes,
2746                                             current->pid % map->num_stripes);
2747                 }
2748
2749         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
2750                 if (rw & (1 << BIO_RW))
2751                         num_stripes = map->num_stripes;
2752                 else if (mirror_num)
2753                         stripe_index = mirror_num - 1;
2754
2755         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
2756                 int factor = map->num_stripes / map->sub_stripes;
2757
2758                 stripe_index = do_div(stripe_nr, factor);
2759                 stripe_index *= map->sub_stripes;
2760
2761                 if (unplug_page || (rw & (1 << BIO_RW)))
2762                         num_stripes = map->sub_stripes;
2763                 else if (mirror_num)
2764                         stripe_index += mirror_num - 1;
2765                 else {
2766                         stripe_index = find_live_mirror(map, stripe_index,
2767                                               map->sub_stripes, stripe_index +
2768                                               current->pid % map->sub_stripes);
2769                 }
2770         } else {
2771                 /*
2772                  * after this do_div call, stripe_nr is the number of stripes
2773                  * on this device we have to walk to find the data, and
2774                  * stripe_index is the number of our device in the stripe array
2775                  */
2776                 stripe_index = do_div(stripe_nr, map->num_stripes);
2777         }
2778         BUG_ON(stripe_index >= map->num_stripes);
2779
2780         for (i = 0; i < num_stripes; i++) {
2781                 if (unplug_page) {
2782                         struct btrfs_device *device;
2783                         struct backing_dev_info *bdi;
2784
2785                         device = map->stripes[stripe_index].dev;
2786                         if (device->bdev) {
2787                                 bdi = blk_get_backing_dev_info(device->bdev);
2788                                 if (bdi->unplug_io_fn)
2789                                         bdi->unplug_io_fn(bdi, unplug_page);
2790                         }
2791                 } else {
2792                         multi->stripes[i].physical =
2793                                 map->stripes[stripe_index].physical +
2794                                 stripe_offset + stripe_nr * map->stripe_len;
2795                         multi->stripes[i].dev = map->stripes[stripe_index].dev;
2796                 }
2797                 stripe_index++;
2798         }
2799         if (multi_ret) {
2800                 *multi_ret = multi;
2801                 multi->num_stripes = num_stripes;
2802                 multi->max_errors = max_errors;
2803         }
2804 out:
2805         free_extent_map(em);
2806         return 0;
2807 }
2808
2809 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
2810                       u64 logical, u64 *length,
2811                       struct btrfs_multi_bio **multi_ret, int mirror_num)
2812 {
2813         return __btrfs_map_block(map_tree, rw, logical, length, multi_ret,
2814                                  mirror_num, NULL);
2815 }
2816
2817 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
2818                      u64 chunk_start, u64 physical, u64 devid,
2819                      u64 **logical, int *naddrs, int *stripe_len)
2820 {
2821         struct extent_map_tree *em_tree = &map_tree->map_tree;
2822         struct extent_map *em;
2823         struct map_lookup *map;
2824         u64 *buf;
2825         u64 bytenr;
2826         u64 length;
2827         u64 stripe_nr;
2828         int i, j, nr = 0;
2829
2830         read_lock(&em_tree->lock);
2831         em = lookup_extent_mapping(em_tree, chunk_start, 1);
2832         read_unlock(&em_tree->lock);
2833
2834         BUG_ON(!em || em->start != chunk_start);
2835         map = (struct map_lookup *)em->bdev;
2836
2837         length = em->len;
2838         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
2839                 do_div(length, map->num_stripes / map->sub_stripes);
2840         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
2841                 do_div(length, map->num_stripes);
2842
2843         buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
2844         BUG_ON(!buf);
2845
2846         for (i = 0; i < map->num_stripes; i++) {
2847                 if (devid && map->stripes[i].dev->devid != devid)
2848                         continue;
2849                 if (map->stripes[i].physical > physical ||
2850                     map->stripes[i].physical + length <= physical)
2851                         continue;
2852
2853                 stripe_nr = physical - map->stripes[i].physical;
2854                 do_div(stripe_nr, map->stripe_len);
2855
2856                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
2857                         stripe_nr = stripe_nr * map->num_stripes + i;
2858                         do_div(stripe_nr, map->sub_stripes);
2859                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
2860                         stripe_nr = stripe_nr * map->num_stripes + i;
2861                 }
2862                 bytenr = chunk_start + stripe_nr * map->stripe_len;
2863                 WARN_ON(nr >= map->num_stripes);
2864                 for (j = 0; j < nr; j++) {
2865                         if (buf[j] == bytenr)
2866                                 break;
2867                 }
2868                 if (j == nr) {
2869                         WARN_ON(nr >= map->num_stripes);
2870                         buf[nr++] = bytenr;
2871                 }
2872         }
2873
2874         *logical = buf;
2875         *naddrs = nr;
2876         *stripe_len = map->stripe_len;
2877
2878         free_extent_map(em);
2879         return 0;
2880 }
2881
2882 int btrfs_unplug_page(struct btrfs_mapping_tree *map_tree,
2883                       u64 logical, struct page *page)
2884 {
2885         u64 length = PAGE_CACHE_SIZE;
2886         return __btrfs_map_block(map_tree, READ, logical, &length,
2887                                  NULL, 0, page);
2888 }
2889
2890 static void end_bio_multi_stripe(struct bio *bio, int err)
2891 {
2892         struct btrfs_multi_bio *multi = bio->bi_private;
2893         int is_orig_bio = 0;
2894
2895         if (err)
2896                 atomic_inc(&multi->error);
2897
2898         if (bio == multi->orig_bio)
2899                 is_orig_bio = 1;
2900
2901         if (atomic_dec_and_test(&multi->stripes_pending)) {
2902                 if (!is_orig_bio) {
2903                         bio_put(bio);
2904                         bio = multi->orig_bio;
2905                 }
2906                 bio->bi_private = multi->private;
2907                 bio->bi_end_io = multi->end_io;
2908                 /* only send an error to the higher layers if it is
2909                  * beyond the tolerance of the multi-bio
2910                  */
2911                 if (atomic_read(&multi->error) > multi->max_errors) {
2912                         err = -EIO;
2913                 } else if (err) {
2914                         /*
2915                          * this bio is actually up to date, we didn't
2916                          * go over the max number of errors
2917                          */
2918                         set_bit(BIO_UPTODATE, &bio->bi_flags);
2919                         err = 0;
2920                 }
2921                 kfree(multi);
2922
2923                 bio_endio(bio, err);
2924         } else if (!is_orig_bio) {
2925                 bio_put(bio);
2926         }
2927 }
2928
2929 struct async_sched {
2930         struct bio *bio;
2931         int rw;
2932         struct btrfs_fs_info *info;
2933         struct btrfs_work work;
2934 };
2935
2936 /*
2937  * see run_scheduled_bios for a description of why bios are collected for
2938  * async submit.
2939  *
2940  * This will add one bio to the pending list for a device and make sure
2941  * the work struct is scheduled.
2942  */
2943 static noinline int schedule_bio(struct btrfs_root *root,
2944                                  struct btrfs_device *device,
2945                                  int rw, struct bio *bio)
2946 {
2947         int should_queue = 1;
2948         struct btrfs_pending_bios *pending_bios;
2949
2950         /* don't bother with additional async steps for reads, right now */
2951         if (!(rw & (1 << BIO_RW))) {
2952                 bio_get(bio);
2953                 submit_bio(rw, bio);
2954                 bio_put(bio);
2955                 return 0;
2956         }
2957
2958         /*
2959          * nr_async_bios allows us to reliably return congestion to the
2960          * higher layers.  Otherwise, the async bio makes it appear we have
2961          * made progress against dirty pages when we've really just put it
2962          * on a queue for later
2963          */
2964         atomic_inc(&root->fs_info->nr_async_bios);
2965         WARN_ON(bio->bi_next);
2966         bio->bi_next = NULL;
2967         bio->bi_rw |= rw;
2968
2969         spin_lock(&device->io_lock);
2970         if (bio_rw_flagged(bio, BIO_RW_SYNCIO))
2971                 pending_bios = &device->pending_sync_bios;
2972         else
2973                 pending_bios = &device->pending_bios;
2974
2975         if (pending_bios->tail)
2976                 pending_bios->tail->bi_next = bio;
2977
2978         pending_bios->tail = bio;
2979         if (!pending_bios->head)
2980                 pending_bios->head = bio;
2981         if (device->running_pending)
2982                 should_queue = 0;
2983
2984         spin_unlock(&device->io_lock);
2985
2986         if (should_queue)
2987                 btrfs_queue_worker(&root->fs_info->submit_workers,
2988                                    &device->work);
2989         return 0;
2990 }
2991
2992 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
2993                   int mirror_num, int async_submit)
2994 {
2995         struct btrfs_mapping_tree *map_tree;
2996         struct btrfs_device *dev;
2997         struct bio *first_bio = bio;
2998         u64 logical = (u64)bio->bi_sector << 9;
2999         u64 length = 0;
3000         u64 map_length;
3001         struct btrfs_multi_bio *multi = NULL;
3002         int ret;
3003         int dev_nr = 0;
3004         int total_devs = 1;
3005
3006         length = bio->bi_size;
3007         map_tree = &root->fs_info->mapping_tree;
3008         map_length = length;
3009
3010         ret = btrfs_map_block(map_tree, rw, logical, &map_length, &multi,
3011                               mirror_num);
3012         BUG_ON(ret);
3013
3014         total_devs = multi->num_stripes;
3015         if (map_length < length) {
3016                 printk(KERN_CRIT "mapping failed logical %llu bio len %llu "
3017                        "len %llu\n", (unsigned long long)logical,
3018                        (unsigned long long)length,
3019                        (unsigned long long)map_length);
3020                 BUG();
3021         }
3022         multi->end_io = first_bio->bi_end_io;
3023         multi->private = first_bio->bi_private;
3024         multi->orig_bio = first_bio;
3025         atomic_set(&multi->stripes_pending, multi->num_stripes);
3026
3027         while (dev_nr < total_devs) {
3028                 if (total_devs > 1) {
3029                         if (dev_nr < total_devs - 1) {
3030                                 bio = bio_clone(first_bio, GFP_NOFS);
3031                                 BUG_ON(!bio);
3032                         } else {
3033                                 bio = first_bio;
3034                         }
3035                         bio->bi_private = multi;
3036                         bio->bi_end_io = end_bio_multi_stripe;
3037                 }
3038                 bio->bi_sector = multi->stripes[dev_nr].physical >> 9;
3039                 dev = multi->stripes[dev_nr].dev;
3040                 BUG_ON(rw == WRITE && !dev->writeable);
3041                 if (dev && dev->bdev) {
3042                         bio->bi_bdev = dev->bdev;
3043                         if (async_submit)
3044                                 schedule_bio(root, dev, rw, bio);
3045                         else
3046                                 submit_bio(rw, bio);
3047                 } else {
3048                         bio->bi_bdev = root->fs_info->fs_devices->latest_bdev;
3049                         bio->bi_sector = logical >> 9;
3050                         bio_endio(bio, -EIO);
3051                 }
3052                 dev_nr++;
3053         }
3054         if (total_devs == 1)
3055                 kfree(multi);
3056         return 0;
3057 }
3058
3059 struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
3060                                        u8 *uuid, u8 *fsid)
3061 {
3062         struct btrfs_device *device;
3063         struct btrfs_fs_devices *cur_devices;
3064
3065         cur_devices = root->fs_info->fs_devices;
3066         while (cur_devices) {
3067                 if (!fsid ||
3068                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
3069                         device = __find_device(&cur_devices->devices,
3070                                                devid, uuid);
3071                         if (device)
3072                                 return device;
3073                 }
3074                 cur_devices = cur_devices->seed;
3075         }
3076         return NULL;
3077 }
3078
3079 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
3080                                             u64 devid, u8 *dev_uuid)
3081 {
3082         struct btrfs_device *device;
3083         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
3084
3085         device = kzalloc(sizeof(*device), GFP_NOFS);
3086         if (!device)
3087                 return NULL;
3088         list_add(&device->dev_list,
3089                  &fs_devices->devices);
3090         device->barriers = 1;
3091         device->dev_root = root->fs_info->dev_root;
3092         device->devid = devid;
3093         device->work.func = pending_bios_fn;
3094         device->fs_devices = fs_devices;
3095         fs_devices->num_devices++;
3096         spin_lock_init(&device->io_lock);
3097         INIT_LIST_HEAD(&device->dev_alloc_list);
3098         memcpy(device->uuid, dev_uuid, BTRFS_UUID_SIZE);
3099         return device;
3100 }
3101
3102 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
3103                           struct extent_buffer *leaf,
3104                           struct btrfs_chunk *chunk)
3105 {
3106         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
3107         struct map_lookup *map;
3108         struct extent_map *em;
3109         u64 logical;
3110         u64 length;
3111         u64 devid;
3112         u8 uuid[BTRFS_UUID_SIZE];
3113         int num_stripes;
3114         int ret;
3115         int i;
3116
3117         logical = key->offset;
3118         length = btrfs_chunk_length(leaf, chunk);
3119
3120         read_lock(&map_tree->map_tree.lock);
3121         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
3122         read_unlock(&map_tree->map_tree.lock);
3123
3124         /* already mapped? */
3125         if (em && em->start <= logical && em->start + em->len > logical) {
3126                 free_extent_map(em);
3127                 return 0;
3128         } else if (em) {
3129                 free_extent_map(em);
3130         }
3131
3132         em = alloc_extent_map(GFP_NOFS);
3133         if (!em)
3134                 return -ENOMEM;
3135         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3136         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
3137         if (!map) {
3138                 free_extent_map(em);
3139                 return -ENOMEM;
3140         }
3141
3142         em->bdev = (struct block_device *)map;
3143         em->start = logical;
3144         em->len = length;
3145         em->block_start = 0;
3146         em->block_len = em->len;
3147
3148         map->num_stripes = num_stripes;
3149         map->io_width = btrfs_chunk_io_width(leaf, chunk);
3150         map->io_align = btrfs_chunk_io_align(leaf, chunk);
3151         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
3152         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
3153         map->type = btrfs_chunk_type(leaf, chunk);
3154         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
3155         for (i = 0; i < num_stripes; i++) {
3156                 map->stripes[i].physical =
3157                         btrfs_stripe_offset_nr(leaf, chunk, i);
3158                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
3159                 read_extent_buffer(leaf, uuid, (unsigned long)
3160                                    btrfs_stripe_dev_uuid_nr(chunk, i),
3161                                    BTRFS_UUID_SIZE);
3162                 map->stripes[i].dev = btrfs_find_device(root, devid, uuid,
3163                                                         NULL);
3164                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
3165                         kfree(map);
3166                         free_extent_map(em);
3167                         return -EIO;
3168                 }
3169                 if (!map->stripes[i].dev) {
3170                         map->stripes[i].dev =
3171                                 add_missing_dev(root, devid, uuid);
3172                         if (!map->stripes[i].dev) {
3173                                 kfree(map);
3174                                 free_extent_map(em);
3175                                 return -EIO;
3176                         }
3177                 }
3178                 map->stripes[i].dev->in_fs_metadata = 1;
3179         }
3180
3181         write_lock(&map_tree->map_tree.lock);
3182         ret = add_extent_mapping(&map_tree->map_tree, em);
3183         write_unlock(&map_tree->map_tree.lock);
3184         BUG_ON(ret);
3185         free_extent_map(em);
3186
3187         return 0;
3188 }
3189
3190 static int fill_device_from_item(struct extent_buffer *leaf,
3191                                  struct btrfs_dev_item *dev_item,
3192                                  struct btrfs_device *device)
3193 {
3194         unsigned long ptr;
3195
3196         device->devid = btrfs_device_id(leaf, dev_item);
3197         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
3198         device->total_bytes = device->disk_total_bytes;
3199         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
3200         device->type = btrfs_device_type(leaf, dev_item);
3201         device->io_align = btrfs_device_io_align(leaf, dev_item);
3202         device->io_width = btrfs_device_io_width(leaf, dev_item);
3203         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
3204
3205         ptr = (unsigned long)btrfs_device_uuid(dev_item);
3206         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
3207
3208         return 0;
3209 }
3210
3211 static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
3212 {
3213         struct btrfs_fs_devices *fs_devices;
3214         int ret;
3215
3216         mutex_lock(&uuid_mutex);
3217
3218         fs_devices = root->fs_info->fs_devices->seed;
3219         while (fs_devices) {
3220                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
3221                         ret = 0;
3222                         goto out;
3223                 }
3224                 fs_devices = fs_devices->seed;
3225         }
3226
3227         fs_devices = find_fsid(fsid);
3228         if (!fs_devices) {
3229                 ret = -ENOENT;
3230                 goto out;
3231         }
3232
3233         fs_devices = clone_fs_devices(fs_devices);
3234         if (IS_ERR(fs_devices)) {
3235                 ret = PTR_ERR(fs_devices);
3236                 goto out;
3237         }
3238
3239         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
3240                                    root->fs_info->bdev_holder);
3241         if (ret)
3242                 goto out;
3243
3244         if (!fs_devices->seeding) {
3245                 __btrfs_close_devices(fs_devices);
3246                 free_fs_devices(fs_devices);
3247                 ret = -EINVAL;
3248                 goto out;
3249         }
3250
3251         fs_devices->seed = root->fs_info->fs_devices->seed;
3252         root->fs_info->fs_devices->seed = fs_devices;
3253 out:
3254         mutex_unlock(&uuid_mutex);
3255         return ret;
3256 }
3257
3258 static int read_one_dev(struct btrfs_root *root,
3259                         struct extent_buffer *leaf,
3260                         struct btrfs_dev_item *dev_item)
3261 {
3262         struct btrfs_device *device;
3263         u64 devid;
3264         int ret;
3265         u8 fs_uuid[BTRFS_UUID_SIZE];
3266         u8 dev_uuid[BTRFS_UUID_SIZE];
3267
3268         devid = btrfs_device_id(leaf, dev_item);
3269         read_extent_buffer(leaf, dev_uuid,
3270                            (unsigned long)btrfs_device_uuid(dev_item),
3271                            BTRFS_UUID_SIZE);
3272         read_extent_buffer(leaf, fs_uuid,
3273                            (unsigned long)btrfs_device_fsid(dev_item),
3274                            BTRFS_UUID_SIZE);
3275
3276         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
3277                 ret = open_seed_devices(root, fs_uuid);
3278                 if (ret && !btrfs_test_opt(root, DEGRADED))
3279                         return ret;
3280         }
3281
3282         device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
3283         if (!device || !device->bdev) {
3284                 if (!btrfs_test_opt(root, DEGRADED))
3285                         return -EIO;
3286
3287                 if (!device) {
3288                         printk(KERN_WARNING "warning devid %llu missing\n",
3289                                (unsigned long long)devid);
3290                         device = add_missing_dev(root, devid, dev_uuid);
3291                         if (!device)
3292                                 return -ENOMEM;
3293                 }
3294         }
3295
3296         if (device->fs_devices != root->fs_info->fs_devices) {
3297                 BUG_ON(device->writeable);
3298                 if (device->generation !=
3299                     btrfs_device_generation(leaf, dev_item))
3300                         return -EINVAL;
3301         }
3302
3303         fill_device_from_item(leaf, dev_item, device);
3304         device->dev_root = root->fs_info->dev_root;
3305         device->in_fs_metadata = 1;
3306         if (device->writeable)
3307                 device->fs_devices->total_rw_bytes += device->total_bytes;
3308         ret = 0;
3309         return ret;
3310 }
3311
3312 int btrfs_read_super_device(struct btrfs_root *root, struct extent_buffer *buf)
3313 {
3314         struct btrfs_dev_item *dev_item;
3315
3316         dev_item = (struct btrfs_dev_item *)offsetof(struct btrfs_super_block,
3317                                                      dev_item);
3318         return read_one_dev(root, buf, dev_item);
3319 }
3320
3321 int btrfs_read_sys_array(struct btrfs_root *root)
3322 {
3323         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
3324         struct extent_buffer *sb;
3325         struct btrfs_disk_key *disk_key;
3326         struct btrfs_chunk *chunk;
3327         u8 *ptr;
3328         unsigned long sb_ptr;
3329         int ret = 0;
3330         u32 num_stripes;
3331         u32 array_size;
3332         u32 len = 0;
3333         u32 cur;
3334         struct btrfs_key key;
3335
3336         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
3337                                           BTRFS_SUPER_INFO_SIZE);
3338         if (!sb)
3339                 return -ENOMEM;
3340         btrfs_set_buffer_uptodate(sb);
3341         btrfs_set_buffer_lockdep_class(sb, 0);
3342
3343         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
3344         array_size = btrfs_super_sys_array_size(super_copy);
3345
3346         ptr = super_copy->sys_chunk_array;
3347         sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
3348         cur = 0;
3349
3350         while (cur < array_size) {
3351                 disk_key = (struct btrfs_disk_key *)ptr;
3352                 btrfs_disk_key_to_cpu(&key, disk_key);
3353
3354                 len = sizeof(*disk_key); ptr += len;
3355                 sb_ptr += len;
3356                 cur += len;
3357
3358                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
3359                         chunk = (struct btrfs_chunk *)sb_ptr;
3360                         ret = read_one_chunk(root, &key, sb, chunk);
3361                         if (ret)
3362                                 break;
3363                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
3364                         len = btrfs_chunk_item_size(num_stripes);
3365                 } else {
3366                         ret = -EIO;
3367                         break;
3368                 }
3369                 ptr += len;
3370                 sb_ptr += len;
3371                 cur += len;
3372         }
3373         free_extent_buffer(sb);
3374         return ret;
3375 }
3376
3377 int btrfs_read_chunk_tree(struct btrfs_root *root)
3378 {
3379         struct btrfs_path *path;
3380         struct extent_buffer *leaf;
3381         struct btrfs_key key;
3382         struct btrfs_key found_key;
3383         int ret;
3384         int slot;
3385
3386         root = root->fs_info->chunk_root;
3387
3388         path = btrfs_alloc_path();
3389         if (!path)
3390                 return -ENOMEM;
3391
3392         /* first we search for all of the device items, and then we
3393          * read in all of the chunk items.  This way we can create chunk
3394          * mappings that reference all of the devices that are afound
3395          */
3396         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
3397         key.offset = 0;
3398         key.type = 0;
3399 again:
3400         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3401         if (ret < 0)
3402                 goto error;
3403         while (1) {
3404                 leaf = path->nodes[0];
3405                 slot = path->slots[0];
3406                 if (slot >= btrfs_header_nritems(leaf)) {
3407                         ret = btrfs_next_leaf(root, path);
3408                         if (ret == 0)
3409                                 continue;
3410                         if (ret < 0)
3411                                 goto error;
3412                         break;
3413                 }
3414                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3415                 if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
3416                         if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
3417                                 break;
3418                         if (found_key.type == BTRFS_DEV_ITEM_KEY) {
3419                                 struct btrfs_dev_item *dev_item;
3420                                 dev_item = btrfs_item_ptr(leaf, slot,
3421                                                   struct btrfs_dev_item);
3422                                 ret = read_one_dev(root, leaf, dev_item);
3423                                 if (ret)
3424                                         goto error;
3425                         }
3426                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
3427                         struct btrfs_chunk *chunk;
3428                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
3429                         ret = read_one_chunk(root, &found_key, leaf, chunk);
3430                         if (ret)
3431                                 goto error;
3432                 }
3433                 path->slots[0]++;
3434         }
3435         if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
3436                 key.objectid = 0;
3437                 btrfs_release_path(root, path);
3438                 goto again;
3439         }
3440         ret = 0;
3441 error:
3442         btrfs_free_path(path);
3443         return ret;
3444 }