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GUI: Fix Tomato RAF theme for all builds. Compilation typo.
[tomato.git] / release / src-rt-6.x.4708 / linux / linux-2.6.36 / fs / btrfs / volumes.c
blobc893e98dfce1ee8e1eb4b3a934a138c253f949f6
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 (cur->bi_rw & REQ_SYNC)
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 printk(KERN_INFO "device fsid %llx-%llx ",
711 *(unsigned long long *)disk_super->fsid,
712 *(unsigned long long *)(disk_super->fsid + 8));
713 }
714 printk(KERN_CONT "devid %llu transid %llu %s\n",
715 (unsigned long long)devid, (unsigned long long)transid, path);
716 ret = device_list_add(path, disk_super, devid, fs_devices_ret);
717
718 brelse(bh);
719 error_close:
720 close_bdev_exclusive(bdev, flags);
721 error:
722 mutex_unlock(&uuid_mutex);
723 return ret;
724 }
725
726 /*
727 * this uses a pretty simple search, the expectation is that it is
728 * called very infrequently and that a given device has a small number
729 * of extents
730 */
731 int find_free_dev_extent(struct btrfs_trans_handle *trans,
732 struct btrfs_device *device, u64 num_bytes,
733 u64 *start, u64 *max_avail)
734 {
735 struct btrfs_key key;
736 struct btrfs_root *root = device->dev_root;
737 struct btrfs_dev_extent *dev_extent = NULL;
738 struct btrfs_path *path;
739 u64 hole_size = 0;
740 u64 last_byte = 0;
741 u64 search_start = 0;
742 u64 search_end = device->total_bytes;
743 int ret;
744 int slot = 0;
745 int start_found;
746 struct extent_buffer *l;
747
748 path = btrfs_alloc_path();
749 if (!path)
750 return -ENOMEM;
751 path->reada = 2;
752 start_found = 0;
753
754
755 /* we don't want to overwrite the superblock on the drive,
756 * so we make sure to start at an offset of at least 1MB
757 */
758 search_start = max((u64)1024 * 1024, search_start);
759
760 if (root->fs_info->alloc_start + num_bytes <= device->total_bytes)
761 search_start = max(root->fs_info->alloc_start, search_start);
762
763 key.objectid = device->devid;
764 key.offset = search_start;
765 key.type = BTRFS_DEV_EXTENT_KEY;
766 ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
767 if (ret < 0)
768 goto error;
769 if (ret > 0) {
770 ret = btrfs_previous_item(root, path, key.objectid, key.type);
771 if (ret < 0)
772 goto error;
773 if (ret > 0)
774 start_found = 1;
775 }
776 l = path->nodes[0];
777 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
778 while (1) {
779 l = path->nodes[0];
780 slot = path->slots[0];
781 if (slot >= btrfs_header_nritems(l)) {
782 ret = btrfs_next_leaf(root, path);
783 if (ret == 0)
784 continue;
785 if (ret < 0)
786 goto error;
787 no_more_items:
788 if (!start_found) {
789 if (search_start >= search_end) {
790 ret = -ENOSPC;
791 goto error;
792 }
793 *start = search_start;
794 start_found = 1;
795 goto check_pending;
796 }
797 *start = last_byte > search_start ?
798 last_byte : search_start;
799 if (search_end <= *start) {
800 ret = -ENOSPC;
801 goto error;
802 }
803 goto check_pending;
804 }
805 btrfs_item_key_to_cpu(l, &key, slot);
806
807 if (key.objectid < device->devid)
808 goto next;
809
810 if (key.objectid > device->devid)
811 goto no_more_items;
812
813 if (key.offset >= search_start && key.offset > last_byte &&
814 start_found) {
815 if (last_byte < search_start)
816 last_byte = search_start;
817 hole_size = key.offset - last_byte;
818
819 if (hole_size > *max_avail)
820 *max_avail = hole_size;
821
822 if (key.offset > last_byte &&
823 hole_size >= num_bytes) {
824 *start = last_byte;
825 goto check_pending;
826 }
827 }
828 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
829 goto next;
830
831 start_found = 1;
832 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
833 last_byte = key.offset + btrfs_dev_extent_length(l, dev_extent);
834 next:
835 path->slots[0]++;
836 cond_resched();
837 }
838 check_pending:
839 /* we have to make sure we didn't find an extent that has already
840 * been allocated by the map tree or the original allocation
841 */
842 BUG_ON(*start < search_start);
843
844 if (*start + num_bytes > search_end) {
845 ret = -ENOSPC;
846 goto error;
847 }
848 /* check for pending inserts here */
849 ret = 0;
850
851 error:
852 btrfs_free_path(path);
853 return ret;
854 }
855
856 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
857 struct btrfs_device *device,
858 u64 start)
859 {
860 int ret;
861 struct btrfs_path *path;
862 struct btrfs_root *root = device->dev_root;
863 struct btrfs_key key;
864 struct btrfs_key found_key;
865 struct extent_buffer *leaf = NULL;
866 struct btrfs_dev_extent *extent = NULL;
867
868 path = btrfs_alloc_path();
869 if (!path)
870 return -ENOMEM;
871
872 key.objectid = device->devid;
873 key.offset = start;
874 key.type = BTRFS_DEV_EXTENT_KEY;
875
876 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
877 if (ret > 0) {
878 ret = btrfs_previous_item(root, path, key.objectid,
879 BTRFS_DEV_EXTENT_KEY);
880 BUG_ON(ret);
881 leaf = path->nodes[0];
882 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
883 extent = btrfs_item_ptr(leaf, path->slots[0],
884 struct btrfs_dev_extent);
885 BUG_ON(found_key.offset > start || found_key.offset +
886 btrfs_dev_extent_length(leaf, extent) < start);
887 ret = 0;
888 } else if (ret == 0) {
889 leaf = path->nodes[0];
890 extent = btrfs_item_ptr(leaf, path->slots[0],
891 struct btrfs_dev_extent);
892 }
893 BUG_ON(ret);
894
895 if (device->bytes_used > 0)
896 device->bytes_used -= btrfs_dev_extent_length(leaf, extent);
897 ret = btrfs_del_item(trans, root, path);
898 BUG_ON(ret);
899
900 btrfs_free_path(path);
901 return ret;
902 }
903
904 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
905 struct btrfs_device *device,
906 u64 chunk_tree, u64 chunk_objectid,
907 u64 chunk_offset, u64 start, u64 num_bytes)
908 {
909 int ret;
910 struct btrfs_path *path;
911 struct btrfs_root *root = device->dev_root;
912 struct btrfs_dev_extent *extent;
913 struct extent_buffer *leaf;
914 struct btrfs_key key;
915
916 WARN_ON(!device->in_fs_metadata);
917 path = btrfs_alloc_path();
918 if (!path)
919 return -ENOMEM;
920
921 key.objectid = device->devid;
922 key.offset = start;
923 key.type = BTRFS_DEV_EXTENT_KEY;
924 ret = btrfs_insert_empty_item(trans, root, path, &key,
925 sizeof(*extent));
926 BUG_ON(ret);
927
928 leaf = path->nodes[0];
929 extent = btrfs_item_ptr(leaf, path->slots[0],
930 struct btrfs_dev_extent);
931 btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
932 btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
933 btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
934
935 write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
936 (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
937 BTRFS_UUID_SIZE);
938
939 btrfs_set_dev_extent_length(leaf, extent, num_bytes);
940 btrfs_mark_buffer_dirty(leaf);
941 btrfs_free_path(path);
942 return ret;
943 }
944
945 static noinline int find_next_chunk(struct btrfs_root *root,
946 u64 objectid, u64 *offset)
947 {
948 struct btrfs_path *path;
949 int ret;
950 struct btrfs_key key;
951 struct btrfs_chunk *chunk;
952 struct btrfs_key found_key;
953
954 path = btrfs_alloc_path();
955 BUG_ON(!path);
956
957 key.objectid = objectid;
958 key.offset = (u64)-1;
959 key.type = BTRFS_CHUNK_ITEM_KEY;
960
961 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
962 if (ret < 0)
963 goto error;
964
965 BUG_ON(ret == 0);
966
967 ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
968 if (ret) {
969 *offset = 0;
970 } else {
971 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
972 path->slots[0]);
973 if (found_key.objectid != objectid)
974 *offset = 0;
975 else {
976 chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
977 struct btrfs_chunk);
978 *offset = found_key.offset +
979 btrfs_chunk_length(path->nodes[0], chunk);
980 }
981 }
982 ret = 0;
983 error:
984 btrfs_free_path(path);
985 return ret;
986 }
987
988 static noinline int find_next_devid(struct btrfs_root *root, u64 *objectid)
989 {
990 int ret;
991 struct btrfs_key key;
992 struct btrfs_key found_key;
993 struct btrfs_path *path;
994
995 root = root->fs_info->chunk_root;
996
997 path = btrfs_alloc_path();
998 if (!path)
999 return -ENOMEM;
1000
1001 key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1002 key.type = BTRFS_DEV_ITEM_KEY;
1003 key.offset = (u64)-1;
1004
1005 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1006 if (ret < 0)
1007 goto error;
1008
1009 BUG_ON(ret == 0);
1010
1011 ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
1012 BTRFS_DEV_ITEM_KEY);
1013 if (ret) {
1014 *objectid = 1;
1015 } else {
1016 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1017 path->slots[0]);
1018 *objectid = found_key.offset + 1;
1019 }
1020 ret = 0;
1021 error:
1022 btrfs_free_path(path);
1023 return ret;
1024 }
1025
1026 /*
1027 * the device information is stored in the chunk root
1028 * the btrfs_device struct should be fully filled in
1029 */
1030 int btrfs_add_device(struct btrfs_trans_handle *trans,
1031 struct btrfs_root *root,
1032 struct btrfs_device *device)
1033 {
1034 int ret;
1035 struct btrfs_path *path;
1036 struct btrfs_dev_item *dev_item;
1037 struct extent_buffer *leaf;
1038 struct btrfs_key key;
1039 unsigned long ptr;
1040
1041 root = root->fs_info->chunk_root;
1042
1043 path = btrfs_alloc_path();
1044 if (!path)
1045 return -ENOMEM;
1046
1047 key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1048 key.type = BTRFS_DEV_ITEM_KEY;
1049 key.offset = device->devid;
1050
1051 ret = btrfs_insert_empty_item(trans, root, path, &key,
1052 sizeof(*dev_item));
1053 if (ret)
1054 goto out;
1055
1056 leaf = path->nodes[0];
1057 dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1058
1059 btrfs_set_device_id(leaf, dev_item, device->devid);
1060 btrfs_set_device_generation(leaf, dev_item, 0);
1061 btrfs_set_device_type(leaf, dev_item, device->type);
1062 btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1063 btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1064 btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1065 btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
1066 btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1067 btrfs_set_device_group(leaf, dev_item, 0);
1068 btrfs_set_device_seek_speed(leaf, dev_item, 0);
1069 btrfs_set_device_bandwidth(leaf, dev_item, 0);
1070 btrfs_set_device_start_offset(leaf, dev_item, 0);
1071
1072 ptr = (unsigned long)btrfs_device_uuid(dev_item);
1073 write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1074 ptr = (unsigned long)btrfs_device_fsid(dev_item);
1075 write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1076 btrfs_mark_buffer_dirty(leaf);
1077
1078 ret = 0;
1079 out:
1080 btrfs_free_path(path);
1081 return ret;
1082 }
1083
1084 static int btrfs_rm_dev_item(struct btrfs_root *root,
1085 struct btrfs_device *device)
1086 {
1087 int ret;
1088 struct btrfs_path *path;
1089 struct btrfs_key key;
1090 struct btrfs_trans_handle *trans;
1091
1092 root = root->fs_info->chunk_root;
1093
1094 path = btrfs_alloc_path();
1095 if (!path)
1096 return -ENOMEM;
1097
1098 trans = btrfs_start_transaction(root, 0);
1099 key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1100 key.type = BTRFS_DEV_ITEM_KEY;
1101 key.offset = device->devid;
1102 lock_chunks(root);
1103
1104 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1105 if (ret < 0)
1106 goto out;
1107
1108 if (ret > 0) {
1109 ret = -ENOENT;
1110 goto out;
1111 }
1112
1113 ret = btrfs_del_item(trans, root, path);
1114 if (ret)
1115 goto out;
1116 out:
1117 btrfs_free_path(path);
1118 unlock_chunks(root);
1119 btrfs_commit_transaction(trans, root);
1120 return ret;
1121 }
1122
1123 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1124 {
1125 struct btrfs_device *device;
1126 struct btrfs_device *next_device;
1127 struct block_device *bdev;
1128 struct buffer_head *bh = NULL;
1129 struct btrfs_super_block *disk_super;
1130 u64 all_avail;
1131 u64 devid;
1132 u64 num_devices;
1133 u8 *dev_uuid;
1134 int ret = 0;
1135
1136 mutex_lock(&uuid_mutex);
1137 mutex_lock(&root->fs_info->volume_mutex);
1138
1139 all_avail = root->fs_info->avail_data_alloc_bits |
1140 root->fs_info->avail_system_alloc_bits |
1141 root->fs_info->avail_metadata_alloc_bits;
1142
1143 if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) &&
1144 root->fs_info->fs_devices->num_devices <= 4) {
1145 printk(KERN_ERR "btrfs: unable to go below four devices "
1146 "on raid10\n");
1147 ret = -EINVAL;
1148 goto out;
1149 }
1150
1151 if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) &&
1152 root->fs_info->fs_devices->num_devices <= 2) {
1153 printk(KERN_ERR "btrfs: unable to go below two "
1154 "devices on raid1\n");
1155 ret = -EINVAL;
1156 goto out;
1157 }
1158
1159 if (strcmp(device_path, "missing") == 0) {
1160 struct list_head *devices;
1161 struct btrfs_device *tmp;
1162
1163 device = NULL;
1164 devices = &root->fs_info->fs_devices->devices;
1165 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1166 list_for_each_entry(tmp, devices, dev_list) {
1167 if (tmp->in_fs_metadata && !tmp->bdev) {
1168 device = tmp;
1169 break;
1170 }
1171 }
1172 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1173 bdev = NULL;
1174 bh = NULL;
1175 disk_super = NULL;
1176 if (!device) {
1177 printk(KERN_ERR "btrfs: no missing devices found to "
1178 "remove\n");
1179 goto out;
1180 }
1181 } else {
1182 bdev = open_bdev_exclusive(device_path, FMODE_READ,
1183 root->fs_info->bdev_holder);
1184 if (IS_ERR(bdev)) {
1185 ret = PTR_ERR(bdev);
1186 goto out;
1187 }
1188
1189 set_blocksize(bdev, 4096);
1190 bh = btrfs_read_dev_super(bdev);
1191 if (!bh) {
1192 ret = -EIO;
1193 goto error_close;
1194 }
1195 disk_super = (struct btrfs_super_block *)bh->b_data;
1196 devid = btrfs_stack_device_id(&disk_super->dev_item);
1197 dev_uuid = disk_super->dev_item.uuid;
1198 device = btrfs_find_device(root, devid, dev_uuid,
1199 disk_super->fsid);
1200 if (!device) {
1201 ret = -ENOENT;
1202 goto error_brelse;
1203 }
1204 }
1205
1206 if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1207 printk(KERN_ERR "btrfs: unable to remove the only writeable "
1208 "device\n");
1209 ret = -EINVAL;
1210 goto error_brelse;
1211 }
1212
1213 if (device->writeable) {
1214 list_del_init(&device->dev_alloc_list);
1215 root->fs_info->fs_devices->rw_devices--;
1216 }
1217
1218 ret = btrfs_shrink_device(device, 0);
1219 if (ret)
1220 goto error_brelse;
1221
1222 ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1223 if (ret)
1224 goto error_brelse;
1225
1226 device->in_fs_metadata = 0;
1227
1228 /*
1229 * the device list mutex makes sure that we don't change
1230 * the device list while someone else is writing out all
1231 * the device supers.
1232 */
1233 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1234 list_del_init(&device->dev_list);
1235 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1236
1237 device->fs_devices->num_devices--;
1238
1239 next_device = list_entry(root->fs_info->fs_devices->devices.next,
1240 struct btrfs_device, dev_list);
1241 if (device->bdev == root->fs_info->sb->s_bdev)
1242 root->fs_info->sb->s_bdev = next_device->bdev;
1243 if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1244 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1245
1246 if (device->bdev) {
1247 close_bdev_exclusive(device->bdev, device->mode);
1248 device->bdev = NULL;
1249 device->fs_devices->open_devices--;
1250 }
1251
1252 num_devices = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
1253 btrfs_set_super_num_devices(&root->fs_info->super_copy, num_devices);
1254
1255 if (device->fs_devices->open_devices == 0) {
1256 struct btrfs_fs_devices *fs_devices;
1257 fs_devices = root->fs_info->fs_devices;
1258 while (fs_devices) {
1259 if (fs_devices->seed == device->fs_devices)
1260 break;
1261 fs_devices = fs_devices->seed;
1262 }
1263 fs_devices->seed = device->fs_devices->seed;
1264 device->fs_devices->seed = NULL;
1265 __btrfs_close_devices(device->fs_devices);
1266 free_fs_devices(device->fs_devices);
1267 }
1268
1269 /*
1270 * at this point, the device is zero sized. We want to
1271 * remove it from the devices list and zero out the old super
1272 */
1273 if (device->writeable) {
1274 /* make sure this device isn't detected as part of
1275 * the FS anymore
1276 */
1277 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1278 set_buffer_dirty(bh);
1279 sync_dirty_buffer(bh);
1280 }
1281
1282 kfree(device->name);
1283 kfree(device);
1284 ret = 0;
1285
1286 error_brelse:
1287 brelse(bh);
1288 error_close:
1289 if (bdev)
1290 close_bdev_exclusive(bdev, FMODE_READ);
1291 out:
1292 mutex_unlock(&root->fs_info->volume_mutex);
1293 mutex_unlock(&uuid_mutex);
1294 return ret;
1295 }
1296
1297 /*
1298 * does all the dirty work required for changing file system's UUID.
1299 */
1300 static int btrfs_prepare_sprout(struct btrfs_trans_handle *trans,
1301 struct btrfs_root *root)
1302 {
1303 struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
1304 struct btrfs_fs_devices *old_devices;
1305 struct btrfs_fs_devices *seed_devices;
1306 struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
1307 struct btrfs_device *device;
1308 u64 super_flags;
1309
1310 BUG_ON(!mutex_is_locked(&uuid_mutex));
1311 if (!fs_devices->seeding)
1312 return -EINVAL;
1313
1314 seed_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
1315 if (!seed_devices)
1316 return -ENOMEM;
1317
1318 old_devices = clone_fs_devices(fs_devices);
1319 if (IS_ERR(old_devices)) {
1320 kfree(seed_devices);
1321 return PTR_ERR(old_devices);
1322 }
1323
1324 list_add(&old_devices->list, &fs_uuids);
1325
1326 memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
1327 seed_devices->opened = 1;
1328 INIT_LIST_HEAD(&seed_devices->devices);
1329 INIT_LIST_HEAD(&seed_devices->alloc_list);
1330 mutex_init(&seed_devices->device_list_mutex);
1331 list_splice_init(&fs_devices->devices, &seed_devices->devices);
1332 list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
1333 list_for_each_entry(device, &seed_devices->devices, dev_list) {
1334 device->fs_devices = seed_devices;
1335 }
1336
1337 fs_devices->seeding = 0;
1338 fs_devices->num_devices = 0;
1339 fs_devices->open_devices = 0;
1340 fs_devices->seed = seed_devices;
1341
1342 generate_random_uuid(fs_devices->fsid);
1343 memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1344 memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1345 super_flags = btrfs_super_flags(disk_super) &
1346 ~BTRFS_SUPER_FLAG_SEEDING;
1347 btrfs_set_super_flags(disk_super, super_flags);
1348
1349 return 0;
1350 }
1351
1352 /*
1353 * strore the expected generation for seed devices in device items.
1354 */
1355 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
1356 struct btrfs_root *root)
1357 {
1358 struct btrfs_path *path;
1359 struct extent_buffer *leaf;
1360 struct btrfs_dev_item *dev_item;
1361 struct btrfs_device *device;
1362 struct btrfs_key key;
1363 u8 fs_uuid[BTRFS_UUID_SIZE];
1364 u8 dev_uuid[BTRFS_UUID_SIZE];
1365 u64 devid;
1366 int ret;
1367
1368 path = btrfs_alloc_path();
1369 if (!path)
1370 return -ENOMEM;
1371
1372 root = root->fs_info->chunk_root;
1373 key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1374 key.offset = 0;
1375 key.type = BTRFS_DEV_ITEM_KEY;
1376
1377 while (1) {
1378 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1379 if (ret < 0)
1380 goto error;
1381
1382 leaf = path->nodes[0];
1383 next_slot:
1384 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1385 ret = btrfs_next_leaf(root, path);
1386 if (ret > 0)
1387 break;
1388 if (ret < 0)
1389 goto error;
1390 leaf = path->nodes[0];
1391 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1392 btrfs_release_path(root, path);
1393 continue;
1394 }
1395
1396 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1397 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
1398 key.type != BTRFS_DEV_ITEM_KEY)
1399 break;
1400
1401 dev_item = btrfs_item_ptr(leaf, path->slots[0],
1402 struct btrfs_dev_item);
1403 devid = btrfs_device_id(leaf, dev_item);
1404 read_extent_buffer(leaf, dev_uuid,
1405 (unsigned long)btrfs_device_uuid(dev_item),
1406 BTRFS_UUID_SIZE);
1407 read_extent_buffer(leaf, fs_uuid,
1408 (unsigned long)btrfs_device_fsid(dev_item),
1409 BTRFS_UUID_SIZE);
1410 device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
1411 BUG_ON(!device);
1412
1413 if (device->fs_devices->seeding) {
1414 btrfs_set_device_generation(leaf, dev_item,
1415 device->generation);
1416 btrfs_mark_buffer_dirty(leaf);
1417 }
1418
1419 path->slots[0]++;
1420 goto next_slot;
1421 }
1422 ret = 0;
1423 error:
1424 btrfs_free_path(path);
1425 return ret;
1426 }
1427
1428 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
1429 {
1430 struct btrfs_trans_handle *trans;
1431 struct btrfs_device *device;
1432 struct block_device *bdev;
1433 struct list_head *devices;
1434 struct super_block *sb = root->fs_info->sb;
1435 u64 total_bytes;
1436 int seeding_dev = 0;
1437 int ret = 0;
1438
1439 if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
1440 return -EINVAL;
1441
1442 bdev = open_bdev_exclusive(device_path, 0, root->fs_info->bdev_holder);
1443 if (IS_ERR(bdev))
1444 return PTR_ERR(bdev);
1445
1446 if (root->fs_info->fs_devices->seeding) {
1447 seeding_dev = 1;
1448 down_write(&sb->s_umount);
1449 mutex_lock(&uuid_mutex);
1450 }
1451
1452 filemap_write_and_wait(bdev->bd_inode->i_mapping);
1453 mutex_lock(&root->fs_info->volume_mutex);
1454
1455 devices = &root->fs_info->fs_devices->devices;
1456 /*
1457 * we have the volume lock, so we don't need the extra
1458 * device list mutex while reading the list here.
1459 */
1460 list_for_each_entry(device, devices, dev_list) {
1461 if (device->bdev == bdev) {
1462 ret = -EEXIST;
1463 goto error;
1464 }
1465 }
1466
1467 device = kzalloc(sizeof(*device), GFP_NOFS);
1468 if (!device) {
1469 /* we can safely leave the fs_devices entry around */
1470 ret = -ENOMEM;
1471 goto error;
1472 }
1473
1474 device->name = kstrdup(device_path, GFP_NOFS);
1475 if (!device->name) {
1476 kfree(device);
1477 ret = -ENOMEM;
1478 goto error;
1479 }
1480
1481 ret = find_next_devid(root, &device->devid);
1482 if (ret) {
1483 kfree(device);
1484 goto error;
1485 }
1486
1487 trans = btrfs_start_transaction(root, 0);
1488 lock_chunks(root);
1489
1490 device->barriers = 1;
1491 device->writeable = 1;
1492 device->work.func = pending_bios_fn;
1493 generate_random_uuid(device->uuid);
1494 spin_lock_init(&device->io_lock);
1495 device->generation = trans->transid;
1496 device->io_width = root->sectorsize;
1497 device->io_align = root->sectorsize;
1498 device->sector_size = root->sectorsize;
1499 device->total_bytes = i_size_read(bdev->bd_inode);
1500 device->disk_total_bytes = device->total_bytes;
1501 device->dev_root = root->fs_info->dev_root;
1502 device->bdev = bdev;
1503 device->in_fs_metadata = 1;
1504 device->mode = 0;
1505 set_blocksize(device->bdev, 4096);
1506
1507 if (seeding_dev) {
1508 sb->s_flags &= ~MS_RDONLY;
1509 ret = btrfs_prepare_sprout(trans, root);
1510 BUG_ON(ret);
1511 }
1512
1513 device->fs_devices = root->fs_info->fs_devices;
1514
1515 /*
1516 * we don't want write_supers to jump in here with our device
1517 * half setup
1518 */
1519 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1520 list_add(&device->dev_list, &root->fs_info->fs_devices->devices);
1521 list_add(&device->dev_alloc_list,
1522 &root->fs_info->fs_devices->alloc_list);
1523 root->fs_info->fs_devices->num_devices++;
1524 root->fs_info->fs_devices->open_devices++;
1525 root->fs_info->fs_devices->rw_devices++;
1526 root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
1527
1528 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
1529 root->fs_info->fs_devices->rotating = 1;
1530
1531 total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
1532 btrfs_set_super_total_bytes(&root->fs_info->super_copy,
1533 total_bytes + device->total_bytes);
1534
1535 total_bytes = btrfs_super_num_devices(&root->fs_info->super_copy);
1536 btrfs_set_super_num_devices(&root->fs_info->super_copy,
1537 total_bytes + 1);
1538 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1539
1540 if (seeding_dev) {
1541 ret = init_first_rw_device(trans, root, device);
1542 BUG_ON(ret);
1543 ret = btrfs_finish_sprout(trans, root);
1544 BUG_ON(ret);
1545 } else {
1546 ret = btrfs_add_device(trans, root, device);
1547 }
1548
1549 /*
1550 * we've got more storage, clear any full flags on the space
1551 * infos
1552 */
1553 btrfs_clear_space_info_full(root->fs_info);
1554
1555 unlock_chunks(root);
1556 btrfs_commit_transaction(trans, root);
1557
1558 if (seeding_dev) {
1559 mutex_unlock(&uuid_mutex);
1560 up_write(&sb->s_umount);
1561
1562 ret = btrfs_relocate_sys_chunks(root);
1563 BUG_ON(ret);
1564 }
1565 out:
1566 mutex_unlock(&root->fs_info->volume_mutex);
1567 return ret;
1568 error:
1569 close_bdev_exclusive(bdev, 0);
1570 if (seeding_dev) {
1571 mutex_unlock(&uuid_mutex);
1572 up_write(&sb->s_umount);
1573 }
1574 goto out;
1575 }
1576
1577 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
1578 struct btrfs_device *device)
1579 {
1580 int ret;
1581 struct btrfs_path *path;
1582 struct btrfs_root *root;
1583 struct btrfs_dev_item *dev_item;
1584 struct extent_buffer *leaf;
1585 struct btrfs_key key;
1586
1587 root = device->dev_root->fs_info->chunk_root;
1588
1589 path = btrfs_alloc_path();
1590 if (!path)
1591 return -ENOMEM;
1592
1593 key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1594 key.type = BTRFS_DEV_ITEM_KEY;
1595 key.offset = device->devid;
1596
1597 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1598 if (ret < 0)
1599 goto out;
1600
1601 if (ret > 0) {
1602 ret = -ENOENT;
1603 goto out;
1604 }
1605
1606 leaf = path->nodes[0];
1607 dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1608
1609 btrfs_set_device_id(leaf, dev_item, device->devid);
1610 btrfs_set_device_type(leaf, dev_item, device->type);
1611 btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1612 btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1613 btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1614 btrfs_set_device_total_bytes(leaf, dev_item, device->disk_total_bytes);
1615 btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1616 btrfs_mark_buffer_dirty(leaf);
1617
1618 out:
1619 btrfs_free_path(path);
1620 return ret;
1621 }
1622
1623 static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
1624 struct btrfs_device *device, u64 new_size)
1625 {
1626 struct btrfs_super_block *super_copy =
1627 &device->dev_root->fs_info->super_copy;
1628 u64 old_total = btrfs_super_total_bytes(super_copy);
1629 u64 diff = new_size - device->total_bytes;
1630
1631 if (!device->writeable)
1632 return -EACCES;
1633 if (new_size <= device->total_bytes)
1634 return -EINVAL;
1635
1636 btrfs_set_super_total_bytes(super_copy, old_total + diff);
1637 device->fs_devices->total_rw_bytes += diff;
1638
1639 device->total_bytes = new_size;
1640 device->disk_total_bytes = new_size;
1641 btrfs_clear_space_info_full(device->dev_root->fs_info);
1642
1643 return btrfs_update_device(trans, device);
1644 }
1645
1646 int btrfs_grow_device(struct btrfs_trans_handle *trans,
1647 struct btrfs_device *device, u64 new_size)
1648 {
1649 int ret;
1650 lock_chunks(device->dev_root);
1651 ret = __btrfs_grow_device(trans, device, new_size);
1652 unlock_chunks(device->dev_root);
1653 return ret;
1654 }
1655
1656 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
1657 struct btrfs_root *root,
1658 u64 chunk_tree, u64 chunk_objectid,
1659 u64 chunk_offset)
1660 {
1661 int ret;
1662 struct btrfs_path *path;
1663 struct btrfs_key key;
1664
1665 root = root->fs_info->chunk_root;
1666 path = btrfs_alloc_path();
1667 if (!path)
1668 return -ENOMEM;
1669
1670 key.objectid = chunk_objectid;
1671 key.offset = chunk_offset;
1672 key.type = BTRFS_CHUNK_ITEM_KEY;
1673
1674 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1675 BUG_ON(ret);
1676
1677 ret = btrfs_del_item(trans, root, path);
1678 BUG_ON(ret);
1679
1680 btrfs_free_path(path);
1681 return 0;
1682 }
1683
1684 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
1685 chunk_offset)
1686 {
1687 struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
1688 struct btrfs_disk_key *disk_key;
1689 struct btrfs_chunk *chunk;
1690 u8 *ptr;
1691 int ret = 0;
1692 u32 num_stripes;
1693 u32 array_size;
1694 u32 len = 0;
1695 u32 cur;
1696 struct btrfs_key key;
1697
1698 array_size = btrfs_super_sys_array_size(super_copy);
1699
1700 ptr = super_copy->sys_chunk_array;
1701 cur = 0;
1702
1703 while (cur < array_size) {
1704 disk_key = (struct btrfs_disk_key *)ptr;
1705 btrfs_disk_key_to_cpu(&key, disk_key);
1706
1707 len = sizeof(*disk_key);
1708
1709 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
1710 chunk = (struct btrfs_chunk *)(ptr + len);
1711 num_stripes = btrfs_stack_chunk_num_stripes(chunk);
1712 len += btrfs_chunk_item_size(num_stripes);
1713 } else {
1714 ret = -EIO;
1715 break;
1716 }
1717 if (key.objectid == chunk_objectid &&
1718 key.offset == chunk_offset) {
1719 memmove(ptr, ptr + len, array_size - (cur + len));
1720 array_size -= len;
1721 btrfs_set_super_sys_array_size(super_copy, array_size);
1722 } else {
1723 ptr += len;
1724 cur += len;
1725 }
1726 }
1727 return ret;
1728 }
1729
1730 static int btrfs_relocate_chunk(struct btrfs_root *root,
1731 u64 chunk_tree, u64 chunk_objectid,
1732 u64 chunk_offset)
1733 {
1734 struct extent_map_tree *em_tree;
1735 struct btrfs_root *extent_root;
1736 struct btrfs_trans_handle *trans;
1737 struct extent_map *em;
1738 struct map_lookup *map;
1739 int ret;
1740 int i;
1741
1742 root = root->fs_info->chunk_root;
1743 extent_root = root->fs_info->extent_root;
1744 em_tree = &root->fs_info->mapping_tree.map_tree;
1745
1746 ret = btrfs_can_relocate(extent_root, chunk_offset);
1747 if (ret)
1748 return -ENOSPC;
1749
1750 /* step one, relocate all the extents inside this chunk */
1751 ret = btrfs_relocate_block_group(extent_root, chunk_offset);
1752 if (ret)
1753 return ret;
1754
1755 trans = btrfs_start_transaction(root, 0);
1756 BUG_ON(!trans);
1757
1758 lock_chunks(root);
1759
1760 /*
1761 * step two, delete the device extents and the
1762 * chunk tree entries
1763 */
1764 read_lock(&em_tree->lock);
1765 em = lookup_extent_mapping(em_tree, chunk_offset, 1);
1766 read_unlock(&em_tree->lock);
1767
1768 BUG_ON(em->start > chunk_offset ||
1769 em->start + em->len < chunk_offset);
1770 map = (struct map_lookup *)em->bdev;
1771
1772 for (i = 0; i < map->num_stripes; i++) {
1773 ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
1774 map->stripes[i].physical);
1775 BUG_ON(ret);
1776
1777 if (map->stripes[i].dev) {
1778 ret = btrfs_update_device(trans, map->stripes[i].dev);
1779 BUG_ON(ret);
1780 }
1781 }
1782 ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
1783 chunk_offset);
1784
1785 BUG_ON(ret);
1786
1787 if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
1788 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
1789 BUG_ON(ret);
1790 }
1791
1792 ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
1793 BUG_ON(ret);
1794
1795 write_lock(&em_tree->lock);
1796 remove_extent_mapping(em_tree, em);
1797 write_unlock(&em_tree->lock);
1798
1799 kfree(map);
1800 em->bdev = NULL;
1801
1802 /* once for the tree */
1803 free_extent_map(em);
1804 /* once for us */
1805 free_extent_map(em);
1806
1807 unlock_chunks(root);
1808 btrfs_end_transaction(trans, root);
1809 return 0;
1810 }
1811
1812 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
1813 {
1814 struct btrfs_root *chunk_root = root->fs_info->chunk_root;
1815 struct btrfs_path *path;
1816 struct extent_buffer *leaf;
1817 struct btrfs_chunk *chunk;
1818 struct btrfs_key key;
1819 struct btrfs_key found_key;
1820 u64 chunk_tree = chunk_root->root_key.objectid;
1821 u64 chunk_type;
1822 bool retried = false;
1823 int failed = 0;
1824 int ret;
1825
1826 path = btrfs_alloc_path();
1827 if (!path)
1828 return -ENOMEM;
1829
1830 again:
1831 key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
1832 key.offset = (u64)-1;
1833 key.type = BTRFS_CHUNK_ITEM_KEY;
1834
1835 while (1) {
1836 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
1837 if (ret < 0)
1838 goto error;
1839 BUG_ON(ret == 0);
1840
1841 ret = btrfs_previous_item(chunk_root, path, key.objectid,
1842 key.type);
1843 if (ret < 0)
1844 goto error;
1845 if (ret > 0)
1846 break;
1847
1848 leaf = path->nodes[0];
1849 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1850
1851 chunk = btrfs_item_ptr(leaf, path->slots[0],
1852 struct btrfs_chunk);
1853 chunk_type = btrfs_chunk_type(leaf, chunk);
1854 btrfs_release_path(chunk_root, path);
1855
1856 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
1857 ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
1858 found_key.objectid,
1859 found_key.offset);
1860 if (ret == -ENOSPC)
1861 failed++;
1862 else if (ret)
1863 BUG();
1864 }
1865
1866 if (found_key.offset == 0)
1867 break;
1868 key.offset = found_key.offset - 1;
1869 }
1870 ret = 0;
1871 if (failed && !retried) {
1872 failed = 0;
1873 retried = true;
1874 goto again;
1875 } else if (failed && retried) {
1876 WARN_ON(1);
1877 ret = -ENOSPC;
1878 }
1879 error:
1880 btrfs_free_path(path);
1881 return ret;
1882 }
1883
1884 static u64 div_factor(u64 num, int factor)
1885 {
1886 if (factor == 10)
1887 return num;
1888 num *= factor;
1889 do_div(num, 10);
1890 return num;
1891 }
1892
1893 int btrfs_balance(struct btrfs_root *dev_root)
1894 {
1895 int ret;
1896 struct list_head *devices = &dev_root->fs_info->fs_devices->devices;
1897 struct btrfs_device *device;
1898 u64 old_size;
1899 u64 size_to_free;
1900 struct btrfs_path *path;
1901 struct btrfs_key key;
1902 struct btrfs_chunk *chunk;
1903 struct btrfs_root *chunk_root = dev_root->fs_info->chunk_root;
1904 struct btrfs_trans_handle *trans;
1905 struct btrfs_key found_key;
1906
1907 if (dev_root->fs_info->sb->s_flags & MS_RDONLY)
1908 return -EROFS;
1909
1910 mutex_lock(&dev_root->fs_info->volume_mutex);
1911 dev_root = dev_root->fs_info->dev_root;
1912
1913 /* step one make some room on all the devices */
1914 list_for_each_entry(device, devices, dev_list) {
1915 old_size = device->total_bytes;
1916 size_to_free = div_factor(old_size, 1);
1917 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
1918 if (!device->writeable ||
1919 device->total_bytes - device->bytes_used > size_to_free)
1920 continue;
1921
1922 ret = btrfs_shrink_device(device, old_size - size_to_free);
1923 if (ret == -ENOSPC)
1924 break;
1925 BUG_ON(ret);
1926
1927 trans = btrfs_start_transaction(dev_root, 0);
1928 BUG_ON(!trans);
1929
1930 ret = btrfs_grow_device(trans, device, old_size);
1931 BUG_ON(ret);
1932
1933 btrfs_end_transaction(trans, dev_root);
1934 }
1935
1936 /* step two, relocate all the chunks */
1937 path = btrfs_alloc_path();
1938 BUG_ON(!path);
1939
1940 key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
1941 key.offset = (u64)-1;
1942 key.type = BTRFS_CHUNK_ITEM_KEY;
1943
1944 while (1) {
1945 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
1946 if (ret < 0)
1947 goto error;
1948
1949 /*
1950 * this shouldn't happen, it means the last relocate
1951 * failed
1952 */
1953 if (ret == 0)
1954 break;
1955
1956 ret = btrfs_previous_item(chunk_root, path, 0,
1957 BTRFS_CHUNK_ITEM_KEY);
1958 if (ret)
1959 break;
1960
1961 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1962 path->slots[0]);
1963 if (found_key.objectid != key.objectid)
1964 break;
1965
1966 chunk = btrfs_item_ptr(path->nodes[0],
1967 path->slots[0],
1968 struct btrfs_chunk);
1969 /* chunk zero is special */
1970 if (found_key.offset == 0)
1971 break;
1972
1973 btrfs_release_path(chunk_root, path);
1974 ret = btrfs_relocate_chunk(chunk_root,
1975 chunk_root->root_key.objectid,
1976 found_key.objectid,
1977 found_key.offset);
1978 BUG_ON(ret && ret != -ENOSPC);
1979 key.offset = found_key.offset - 1;
1980 }
1981 ret = 0;
1982 error:
1983 btrfs_free_path(path);
1984 mutex_unlock(&dev_root->fs_info->volume_mutex);
1985 return ret;
1986 }
1987
1988 /*
1989 * shrinking a device means finding all of the device extents past
1990 * the new size, and then following the back refs to the chunks.
1991 * The chunk relocation code actually frees the device extent
1992 */
1993 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
1994 {
1995 struct btrfs_trans_handle *trans;
1996 struct btrfs_root *root = device->dev_root;
1997 struct btrfs_dev_extent *dev_extent = NULL;
1998 struct btrfs_path *path;
1999 u64 length;
2000 u64 chunk_tree;
2001 u64 chunk_objectid;
2002 u64 chunk_offset;
2003 int ret;
2004 int slot;
2005 int failed = 0;
2006 bool retried = false;
2007 struct extent_buffer *l;
2008 struct btrfs_key key;
2009 struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
2010 u64 old_total = btrfs_super_total_bytes(super_copy);
2011 u64 old_size = device->total_bytes;
2012 u64 diff = device->total_bytes - new_size;
2013
2014 if (new_size >= device->total_bytes)
2015 return -EINVAL;
2016
2017 path = btrfs_alloc_path();
2018 if (!path)
2019 return -ENOMEM;
2020
2021 path->reada = 2;
2022
2023 lock_chunks(root);
2024
2025 device->total_bytes = new_size;
2026 if (device->writeable)
2027 device->fs_devices->total_rw_bytes -= diff;
2028 unlock_chunks(root);
2029
2030 again:
2031 key.objectid = device->devid;
2032 key.offset = (u64)-1;
2033 key.type = BTRFS_DEV_EXTENT_KEY;
2034
2035 while (1) {
2036 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2037 if (ret < 0)
2038 goto done;
2039
2040 ret = btrfs_previous_item(root, path, 0, key.type);
2041 if (ret < 0)
2042 goto done;
2043 if (ret) {
2044 ret = 0;
2045 btrfs_release_path(root, path);
2046 break;
2047 }
2048
2049 l = path->nodes[0];
2050 slot = path->slots[0];
2051 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
2052
2053 if (key.objectid != device->devid) {
2054 btrfs_release_path(root, path);
2055 break;
2056 }
2057
2058 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
2059 length = btrfs_dev_extent_length(l, dev_extent);
2060
2061 if (key.offset + length <= new_size) {
2062 btrfs_release_path(root, path);
2063 break;
2064 }
2065
2066 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
2067 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
2068 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
2069 btrfs_release_path(root, path);
2070
2071 ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
2072 chunk_offset);
2073 if (ret && ret != -ENOSPC)
2074 goto done;
2075 if (ret == -ENOSPC)
2076 failed++;
2077 key.offset -= 1;
2078 }
2079
2080 if (failed && !retried) {
2081 failed = 0;
2082 retried = true;
2083 goto again;
2084 } else if (failed && retried) {
2085 ret = -ENOSPC;
2086 lock_chunks(root);
2087
2088 device->total_bytes = old_size;
2089 if (device->writeable)
2090 device->fs_devices->total_rw_bytes += diff;
2091 unlock_chunks(root);
2092 goto done;
2093 }
2094
2095 /* Shrinking succeeded, else we would be at "done". */
2096 trans = btrfs_start_transaction(root, 0);
2097 lock_chunks(root);
2098
2099 device->disk_total_bytes = new_size;
2100 /* Now btrfs_update_device() will change the on-disk size. */
2101 ret = btrfs_update_device(trans, device);
2102 if (ret) {
2103 unlock_chunks(root);
2104 btrfs_end_transaction(trans, root);
2105 goto done;
2106 }
2107 WARN_ON(diff > old_total);
2108 btrfs_set_super_total_bytes(super_copy, old_total - diff);
2109 unlock_chunks(root);
2110 btrfs_end_transaction(trans, root);
2111 done:
2112 btrfs_free_path(path);
2113 return ret;
2114 }
2115
2116 static int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
2117 struct btrfs_root *root,
2118 struct btrfs_key *key,
2119 struct btrfs_chunk *chunk, int item_size)
2120 {
2121 struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
2122 struct btrfs_disk_key disk_key;
2123 u32 array_size;
2124 u8 *ptr;
2125
2126 array_size = btrfs_super_sys_array_size(super_copy);
2127 if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
2128 return -EFBIG;
2129
2130 ptr = super_copy->sys_chunk_array + array_size;
2131 btrfs_cpu_key_to_disk(&disk_key, key);
2132 memcpy(ptr, &disk_key, sizeof(disk_key));
2133 ptr += sizeof(disk_key);
2134 memcpy(ptr, chunk, item_size);
2135 item_size += sizeof(disk_key);
2136 btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
2137 return 0;
2138 }
2139
2140 static noinline u64 chunk_bytes_by_type(u64 type, u64 calc_size,
2141 int num_stripes, int sub_stripes)
2142 {
2143 if (type & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_DUP))
2144 return calc_size;
2145 else if (type & BTRFS_BLOCK_GROUP_RAID10)
2146 return calc_size * (num_stripes / sub_stripes);
2147 else
2148 return calc_size * num_stripes;
2149 }
2150
2151 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
2152 struct btrfs_root *extent_root,
2153 struct map_lookup **map_ret,
2154 u64 *num_bytes, u64 *stripe_size,
2155 u64 start, u64 type)
2156 {
2157 struct btrfs_fs_info *info = extent_root->fs_info;
2158 struct btrfs_device *device = NULL;
2159 struct btrfs_fs_devices *fs_devices = info->fs_devices;
2160 struct list_head *cur;
2161 struct map_lookup *map = NULL;
2162 struct extent_map_tree *em_tree;
2163 struct extent_map *em;
2164 struct list_head private_devs;
2165 int min_stripe_size = 1 * 1024 * 1024;
2166 u64 calc_size = 1024 * 1024 * 1024;
2167 u64 max_chunk_size = calc_size;
2168 u64 min_free;
2169 u64 avail;
2170 u64 max_avail = 0;
2171 u64 dev_offset;
2172 int num_stripes = 1;
2173 int min_stripes = 1;
2174 int sub_stripes = 0;
2175 int looped = 0;
2176 int ret;
2177 int index;
2178 int stripe_len = 64 * 1024;
2179
2180 if ((type & BTRFS_BLOCK_GROUP_RAID1) &&
2181 (type & BTRFS_BLOCK_GROUP_DUP)) {
2182 WARN_ON(1);
2183 type &= ~BTRFS_BLOCK_GROUP_DUP;
2184 }
2185 if (list_empty(&fs_devices->alloc_list))
2186 return -ENOSPC;
2187
2188 if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
2189 num_stripes = fs_devices->rw_devices;
2190 min_stripes = 2;
2191 }
2192 if (type & (BTRFS_BLOCK_GROUP_DUP)) {
2193 num_stripes = 2;
2194 min_stripes = 2;
2195 }
2196 if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
2197 if (fs_devices->rw_devices < 2)
2198 return -ENOSPC;
2199 num_stripes = 2;
2200 min_stripes = 2;
2201 }
2202 if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
2203 num_stripes = fs_devices->rw_devices;
2204 if (num_stripes < 4)
2205 return -ENOSPC;
2206 num_stripes &= ~(u32)1;
2207 sub_stripes = 2;
2208 min_stripes = 4;
2209 }
2210
2211 if (type & BTRFS_BLOCK_GROUP_DATA) {
2212 max_chunk_size = 10 * calc_size;
2213 min_stripe_size = 64 * 1024 * 1024;
2214 } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
2215 max_chunk_size = 256 * 1024 * 1024;
2216 min_stripe_size = 32 * 1024 * 1024;
2217 } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
2218 calc_size = 8 * 1024 * 1024;
2219 max_chunk_size = calc_size * 2;
2220 min_stripe_size = 1 * 1024 * 1024;
2221 }
2222
2223 /* we don't want a chunk larger than 10% of writeable space */
2224 max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
2225 max_chunk_size);
2226
2227 again:
2228 max_avail = 0;
2229 if (!map || map->num_stripes != num_stripes) {
2230 kfree(map);
2231 map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
2232 if (!map)
2233 return -ENOMEM;
2234 map->num_stripes = num_stripes;
2235 }
2236
2237 if (calc_size * num_stripes > max_chunk_size) {
2238 calc_size = max_chunk_size;
2239 do_div(calc_size, num_stripes);
2240 do_div(calc_size, stripe_len);
2241 calc_size *= stripe_len;
2242 }
2243
2244 /* we don't want tiny stripes */
2245 if (!looped)
2246 calc_size = max_t(u64, min_stripe_size, calc_size);
2247
2248 /*
2249 * we're about to do_div by the stripe_len so lets make sure
2250 * we end up with something bigger than a stripe
2251 */
2252 calc_size = max_t(u64, calc_size, stripe_len * 4);
2253
2254 do_div(calc_size, stripe_len);
2255 calc_size *= stripe_len;
2256
2257 cur = fs_devices->alloc_list.next;
2258 index = 0;
2259
2260 if (type & BTRFS_BLOCK_GROUP_DUP)
2261 min_free = calc_size * 2;
2262 else
2263 min_free = calc_size;
2264
2265 /*
2266 * we add 1MB because we never use the first 1MB of the device, unless
2267 * we've looped, then we are likely allocating the maximum amount of
2268 * space left already
2269 */
2270 if (!looped)
2271 min_free += 1024 * 1024;
2272
2273 INIT_LIST_HEAD(&private_devs);
2274 while (index < num_stripes) {
2275 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
2276 BUG_ON(!device->writeable);
2277 if (device->total_bytes > device->bytes_used)
2278 avail = device->total_bytes - device->bytes_used;
2279 else
2280 avail = 0;
2281 cur = cur->next;
2282
2283 if (device->in_fs_metadata && avail >= min_free) {
2284 ret = find_free_dev_extent(trans, device,
2285 min_free, &dev_offset,
2286 &max_avail);
2287 if (ret == 0) {
2288 list_move_tail(&device->dev_alloc_list,
2289 &private_devs);
2290 map->stripes[index].dev = device;
2291 map->stripes[index].physical = dev_offset;
2292 index++;
2293 if (type & BTRFS_BLOCK_GROUP_DUP) {
2294 map->stripes[index].dev = device;
2295 map->stripes[index].physical =
2296 dev_offset + calc_size;
2297 index++;
2298 }
2299 }
2300 } else if (device->in_fs_metadata && avail > max_avail)
2301 max_avail = avail;
2302 if (cur == &fs_devices->alloc_list)
2303 break;
2304 }
2305 list_splice(&private_devs, &fs_devices->alloc_list);
2306 if (index < num_stripes) {
2307 if (index >= min_stripes) {
2308 num_stripes = index;
2309 if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
2310 num_stripes /= sub_stripes;
2311 num_stripes *= sub_stripes;
2312 }
2313 looped = 1;
2314 goto again;
2315 }
2316 if (!looped && max_avail > 0) {
2317 looped = 1;
2318 calc_size = max_avail;
2319 goto again;
2320 }
2321 kfree(map);
2322 return -ENOSPC;
2323 }
2324 map->sector_size = extent_root->sectorsize;
2325 map->stripe_len = stripe_len;
2326 map->io_align = stripe_len;
2327 map->io_width = stripe_len;
2328 map->type = type;
2329 map->num_stripes = num_stripes;
2330 map->sub_stripes = sub_stripes;
2331
2332 *map_ret = map;
2333 *stripe_size = calc_size;
2334 *num_bytes = chunk_bytes_by_type(type, calc_size,
2335 num_stripes, sub_stripes);
2336
2337 em = alloc_extent_map(GFP_NOFS);
2338 if (!em) {
2339 kfree(map);
2340 return -ENOMEM;
2341 }
2342 em->bdev = (struct block_device *)map;
2343 em->start = start;
2344 em->len = *num_bytes;
2345 em->block_start = 0;
2346 em->block_len = em->len;
2347
2348 em_tree = &extent_root->fs_info->mapping_tree.map_tree;
2349 write_lock(&em_tree->lock);
2350 ret = add_extent_mapping(em_tree, em);
2351 write_unlock(&em_tree->lock);
2352 BUG_ON(ret);
2353 free_extent_map(em);
2354
2355 ret = btrfs_make_block_group(trans, extent_root, 0, type,
2356 BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2357 start, *num_bytes);
2358 BUG_ON(ret);
2359
2360 index = 0;
2361 while (index < map->num_stripes) {
2362 device = map->stripes[index].dev;
2363 dev_offset = map->stripes[index].physical;
2364
2365 ret = btrfs_alloc_dev_extent(trans, device,
2366 info->chunk_root->root_key.objectid,
2367 BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2368 start, dev_offset, calc_size);
2369 BUG_ON(ret);
2370 index++;
2371 }
2372
2373 return 0;
2374 }
2375
2376 static int __finish_chunk_alloc(struct btrfs_trans_handle *trans,
2377 struct btrfs_root *extent_root,
2378 struct map_lookup *map, u64 chunk_offset,
2379 u64 chunk_size, u64 stripe_size)
2380 {
2381 u64 dev_offset;
2382 struct btrfs_key key;
2383 struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
2384 struct btrfs_device *device;
2385 struct btrfs_chunk *chunk;
2386 struct btrfs_stripe *stripe;
2387 size_t item_size = btrfs_chunk_item_size(map->num_stripes);
2388 int index = 0;
2389 int ret;
2390
2391 chunk = kzalloc(item_size, GFP_NOFS);
2392 if (!chunk)
2393 return -ENOMEM;
2394
2395 index = 0;
2396 while (index < map->num_stripes) {
2397 device = map->stripes[index].dev;
2398 device->bytes_used += stripe_size;
2399 ret = btrfs_update_device(trans, device);
2400 BUG_ON(ret);
2401 index++;
2402 }
2403
2404 index = 0;
2405 stripe = &chunk->stripe;
2406 while (index < map->num_stripes) {
2407 device = map->stripes[index].dev;
2408 dev_offset = map->stripes[index].physical;
2409
2410 btrfs_set_stack_stripe_devid(stripe, device->devid);
2411 btrfs_set_stack_stripe_offset(stripe, dev_offset);
2412 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
2413 stripe++;
2414 index++;
2415 }
2416
2417 btrfs_set_stack_chunk_length(chunk, chunk_size);
2418 btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
2419 btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
2420 btrfs_set_stack_chunk_type(chunk, map->type);
2421 btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
2422 btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
2423 btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
2424 btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
2425 btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
2426
2427 key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2428 key.type = BTRFS_CHUNK_ITEM_KEY;
2429 key.offset = chunk_offset;
2430
2431 ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
2432 BUG_ON(ret);
2433
2434 if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2435 ret = btrfs_add_system_chunk(trans, chunk_root, &key, chunk,
2436 item_size);
2437 BUG_ON(ret);
2438 }
2439 kfree(chunk);
2440 return 0;
2441 }
2442
2443 /*
2444 * Chunk allocation falls into two parts. The first part does works
2445 * that make the new allocated chunk useable, but not do any operation
2446 * that modifies the chunk tree. The second part does the works that
2447 * require modifying the chunk tree. This division is important for the
2448 * bootstrap process of adding storage to a seed btrfs.
2449 */
2450 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
2451 struct btrfs_root *extent_root, u64 type)
2452 {
2453 u64 chunk_offset;
2454 u64 chunk_size;
2455 u64 stripe_size;
2456 struct map_lookup *map;
2457 struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
2458 int ret;
2459
2460 ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2461 &chunk_offset);
2462 if (ret)
2463 return ret;
2464
2465 ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
2466 &stripe_size, chunk_offset, type);
2467 if (ret)
2468 return ret;
2469
2470 ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
2471 chunk_size, stripe_size);
2472 BUG_ON(ret);
2473 return 0;
2474 }
2475
2476 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
2477 struct btrfs_root *root,
2478 struct btrfs_device *device)
2479 {
2480 u64 chunk_offset;
2481 u64 sys_chunk_offset;
2482 u64 chunk_size;
2483 u64 sys_chunk_size;
2484 u64 stripe_size;
2485 u64 sys_stripe_size;
2486 u64 alloc_profile;
2487 struct map_lookup *map;
2488 struct map_lookup *sys_map;
2489 struct btrfs_fs_info *fs_info = root->fs_info;
2490 struct btrfs_root *extent_root = fs_info->extent_root;
2491 int ret;
2492
2493 ret = find_next_chunk(fs_info->chunk_root,
2494 BTRFS_FIRST_CHUNK_TREE_OBJECTID, &chunk_offset);
2495 BUG_ON(ret);
2496
2497 alloc_profile = BTRFS_BLOCK_GROUP_METADATA |
2498 (fs_info->metadata_alloc_profile &
2499 fs_info->avail_metadata_alloc_bits);
2500 alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
2501
2502 ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
2503 &stripe_size, chunk_offset, alloc_profile);
2504 BUG_ON(ret);
2505
2506 sys_chunk_offset = chunk_offset + chunk_size;
2507
2508 alloc_profile = BTRFS_BLOCK_GROUP_SYSTEM |
2509 (fs_info->system_alloc_profile &
2510 fs_info->avail_system_alloc_bits);
2511 alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
2512
2513 ret = __btrfs_alloc_chunk(trans, extent_root, &sys_map,
2514 &sys_chunk_size, &sys_stripe_size,
2515 sys_chunk_offset, alloc_profile);
2516 BUG_ON(ret);
2517
2518 ret = btrfs_add_device(trans, fs_info->chunk_root, device);
2519 BUG_ON(ret);
2520
2521 /*
2522 * Modifying chunk tree needs allocating new blocks from both
2523 * system block group and metadata block group. So we only can
2524 * do operations require modifying the chunk tree after both
2525 * block groups were created.
2526 */
2527 ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
2528 chunk_size, stripe_size);
2529 BUG_ON(ret);
2530
2531 ret = __finish_chunk_alloc(trans, extent_root, sys_map,
2532 sys_chunk_offset, sys_chunk_size,
2533 sys_stripe_size);
2534 BUG_ON(ret);
2535 return 0;
2536 }
2537
2538 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
2539 {
2540 struct extent_map *em;
2541 struct map_lookup *map;
2542 struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
2543 int readonly = 0;
2544 int i;
2545
2546 read_lock(&map_tree->map_tree.lock);
2547 em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
2548 read_unlock(&map_tree->map_tree.lock);
2549 if (!em)
2550 return 1;
2551
2552 if (btrfs_test_opt(root, DEGRADED)) {
2553 free_extent_map(em);
2554 return 0;
2555 }
2556
2557 map = (struct map_lookup *)em->bdev;
2558 for (i = 0; i < map->num_stripes; i++) {
2559 if (!map->stripes[i].dev->writeable) {
2560 readonly = 1;
2561 break;
2562 }
2563 }
2564 free_extent_map(em);
2565 return readonly;
2566 }
2567
2568 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
2569 {
2570 extent_map_tree_init(&tree->map_tree, GFP_NOFS);
2571 }
2572
2573 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
2574 {
2575 struct extent_map *em;
2576
2577 while (1) {
2578 write_lock(&tree->map_tree.lock);
2579 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
2580 if (em)
2581 remove_extent_mapping(&tree->map_tree, em);
2582 write_unlock(&tree->map_tree.lock);
2583 if (!em)
2584 break;
2585 kfree(em->bdev);
2586 /* once for us */
2587 free_extent_map(em);
2588 /* once for the tree */
2589 free_extent_map(em);
2590 }
2591 }
2592
2593 int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
2594 {
2595 struct extent_map *em;
2596 struct map_lookup *map;
2597 struct extent_map_tree *em_tree = &map_tree->map_tree;
2598 int ret;
2599
2600 read_lock(&em_tree->lock);
2601 em = lookup_extent_mapping(em_tree, logical, len);
2602 read_unlock(&em_tree->lock);
2603 BUG_ON(!em);
2604
2605 BUG_ON(em->start > logical || em->start + em->len < logical);
2606 map = (struct map_lookup *)em->bdev;
2607 if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
2608 ret = map->num_stripes;
2609 else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
2610 ret = map->sub_stripes;
2611 else
2612 ret = 1;
2613 free_extent_map(em);
2614 return ret;
2615 }
2616
2617 static int find_live_mirror(struct map_lookup *map, int first, int num,
2618 int optimal)
2619 {
2620 int i;
2621 if (map->stripes[optimal].dev->bdev)
2622 return optimal;
2623 for (i = first; i < first + num; i++) {
2624 if (map->stripes[i].dev->bdev)
2625 return i;
2626 }
2627 /* we couldn't find one that doesn't fail. Just return something
2628 * and the io error handling code will clean up eventually
2629 */
2630 return optimal;
2631 }
2632
2633 static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
2634 u64 logical, u64 *length,
2635 struct btrfs_multi_bio **multi_ret,
2636 int mirror_num, struct page *unplug_page)
2637 {
2638 struct extent_map *em;
2639 struct map_lookup *map;
2640 struct extent_map_tree *em_tree = &map_tree->map_tree;
2641 u64 offset;
2642 u64 stripe_offset;
2643 u64 stripe_nr;
2644 int stripes_allocated = 8;
2645 int stripes_required = 1;
2646 int stripe_index;
2647 int i;
2648 int num_stripes;
2649 int max_errors = 0;
2650 struct btrfs_multi_bio *multi = NULL;
2651
2652 if (multi_ret && !(rw & REQ_WRITE))
2653 stripes_allocated = 1;
2654 again:
2655 if (multi_ret) {
2656 multi = kzalloc(btrfs_multi_bio_size(stripes_allocated),
2657 GFP_NOFS);
2658 if (!multi)
2659 return -ENOMEM;
2660
2661 atomic_set(&multi->error, 0);
2662 }
2663
2664 read_lock(&em_tree->lock);
2665 em = lookup_extent_mapping(em_tree, logical, *length);
2666 read_unlock(&em_tree->lock);
2667
2668 if (!em && unplug_page) {
2669 kfree(multi);
2670 return 0;
2671 }
2672
2673 if (!em) {
2674 printk(KERN_CRIT "unable to find logical %llu len %llu\n",
2675 (unsigned long long)logical,
2676 (unsigned long long)*length);
2677 BUG();
2678 }
2679
2680 BUG_ON(em->start > logical || em->start + em->len < logical);
2681 map = (struct map_lookup *)em->bdev;
2682 offset = logical - em->start;
2683
2684 if (mirror_num > map->num_stripes)
2685 mirror_num = 0;
2686
2687 /* if our multi bio struct is too small, back off and try again */
2688 if (rw & REQ_WRITE) {
2689 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
2690 BTRFS_BLOCK_GROUP_DUP)) {
2691 stripes_required = map->num_stripes;
2692 max_errors = 1;
2693 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
2694 stripes_required = map->sub_stripes;
2695 max_errors = 1;
2696 }
2697 }
2698 if (multi_ret && (rw & REQ_WRITE) &&
2699 stripes_allocated < stripes_required) {
2700 stripes_allocated = map->num_stripes;
2701 free_extent_map(em);
2702 kfree(multi);
2703 goto again;
2704 }
2705 stripe_nr = offset;
2706 /*
2707 * stripe_nr counts the total number of stripes we have to stride
2708 * to get to this block
2709 */
2710 do_div(stripe_nr, map->stripe_len);
2711
2712 stripe_offset = stripe_nr * map->stripe_len;
2713 BUG_ON(offset < stripe_offset);
2714
2715 /* stripe_offset is the offset of this block in its stripe*/
2716 stripe_offset = offset - stripe_offset;
2717
2718 if (map->type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
2719 BTRFS_BLOCK_GROUP_RAID10 |
2720 BTRFS_BLOCK_GROUP_DUP)) {
2721 /* we limit the length of each bio to what fits in a stripe */
2722 *length = min_t(u64, em->len - offset,
2723 map->stripe_len - stripe_offset);
2724 } else {
2725 *length = em->len - offset;
2726 }
2727
2728 if (!multi_ret && !unplug_page)
2729 goto out;
2730
2731 num_stripes = 1;
2732 stripe_index = 0;
2733 if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
2734 if (unplug_page || (rw & REQ_WRITE))
2735 num_stripes = map->num_stripes;
2736 else if (mirror_num)
2737 stripe_index = mirror_num - 1;
2738 else {
2739 stripe_index = find_live_mirror(map, 0,
2740 map->num_stripes,
2741 current->pid % map->num_stripes);
2742 }
2743
2744 } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
2745 if (rw & REQ_WRITE)
2746 num_stripes = map->num_stripes;
2747 else if (mirror_num)
2748 stripe_index = mirror_num - 1;
2749
2750 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
2751 int factor = map->num_stripes / map->sub_stripes;
2752
2753 stripe_index = do_div(stripe_nr, factor);
2754 stripe_index *= map->sub_stripes;
2755
2756 if (unplug_page || (rw & REQ_WRITE))
2757 num_stripes = map->sub_stripes;
2758 else if (mirror_num)
2759 stripe_index += mirror_num - 1;
2760 else {
2761 stripe_index = find_live_mirror(map, stripe_index,
2762 map->sub_stripes, stripe_index +
2763 current->pid % map->sub_stripes);
2764 }
2765 } else {
2766 /*
2767 * after this do_div call, stripe_nr is the number of stripes
2768 * on this device we have to walk to find the data, and
2769 * stripe_index is the number of our device in the stripe array
2770 */
2771 stripe_index = do_div(stripe_nr, map->num_stripes);
2772 }
2773 BUG_ON(stripe_index >= map->num_stripes);
2774
2775 for (i = 0; i < num_stripes; i++) {
2776 if (unplug_page) {
2777 struct btrfs_device *device;
2778 struct backing_dev_info *bdi;
2779
2780 device = map->stripes[stripe_index].dev;
2781 if (device->bdev) {
2782 bdi = blk_get_backing_dev_info(device->bdev);
2783 if (bdi->unplug_io_fn)
2784 bdi->unplug_io_fn(bdi, unplug_page);
2785 }
2786 } else {
2787 multi->stripes[i].physical =
2788 map->stripes[stripe_index].physical +
2789 stripe_offset + stripe_nr * map->stripe_len;
2790 multi->stripes[i].dev = map->stripes[stripe_index].dev;
2791 }
2792 stripe_index++;
2793 }
2794 if (multi_ret) {
2795 *multi_ret = multi;
2796 multi->num_stripes = num_stripes;
2797 multi->max_errors = max_errors;
2798 }
2799 out:
2800 free_extent_map(em);
2801 return 0;
2802 }
2803
2804 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
2805 u64 logical, u64 *length,
2806 struct btrfs_multi_bio **multi_ret, int mirror_num)
2807 {
2808 return __btrfs_map_block(map_tree, rw, logical, length, multi_ret,
2809 mirror_num, NULL);
2810 }
2811
2812 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
2813 u64 chunk_start, u64 physical, u64 devid,
2814 u64 **logical, int *naddrs, int *stripe_len)
2815 {
2816 struct extent_map_tree *em_tree = &map_tree->map_tree;
2817 struct extent_map *em;
2818 struct map_lookup *map;
2819 u64 *buf;
2820 u64 bytenr;
2821 u64 length;
2822 u64 stripe_nr;
2823 int i, j, nr = 0;
2824
2825 read_lock(&em_tree->lock);
2826 em = lookup_extent_mapping(em_tree, chunk_start, 1);
2827 read_unlock(&em_tree->lock);
2828
2829 BUG_ON(!em || em->start != chunk_start);
2830 map = (struct map_lookup *)em->bdev;
2831
2832 length = em->len;
2833 if (map->type & BTRFS_BLOCK_GROUP_RAID10)
2834 do_div(length, map->num_stripes / map->sub_stripes);
2835 else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
2836 do_div(length, map->num_stripes);
2837
2838 buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
2839 BUG_ON(!buf);
2840
2841 for (i = 0; i < map->num_stripes; i++) {
2842 if (devid && map->stripes[i].dev->devid != devid)
2843 continue;
2844 if (map->stripes[i].physical > physical ||
2845 map->stripes[i].physical + length <= physical)
2846 continue;
2847
2848 stripe_nr = physical - map->stripes[i].physical;
2849 do_div(stripe_nr, map->stripe_len);
2850
2851 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
2852 stripe_nr = stripe_nr * map->num_stripes + i;
2853 do_div(stripe_nr, map->sub_stripes);
2854 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
2855 stripe_nr = stripe_nr * map->num_stripes + i;
2856 }
2857 bytenr = chunk_start + stripe_nr * map->stripe_len;
2858 WARN_ON(nr >= map->num_stripes);
2859 for (j = 0; j < nr; j++) {
2860 if (buf[j] == bytenr)
2861 break;
2862 }
2863 if (j == nr) {
2864 WARN_ON(nr >= map->num_stripes);
2865 buf[nr++] = bytenr;
2866 }
2867 }
2868
2869 *logical = buf;
2870 *naddrs = nr;
2871 *stripe_len = map->stripe_len;
2872
2873 free_extent_map(em);
2874 return 0;
2875 }
2876
2877 int btrfs_unplug_page(struct btrfs_mapping_tree *map_tree,
2878 u64 logical, struct page *page)
2879 {
2880 u64 length = PAGE_CACHE_SIZE;
2881 return __btrfs_map_block(map_tree, READ, logical, &length,
2882 NULL, 0, page);
2883 }
2884
2885 static void end_bio_multi_stripe(struct bio *bio, int err)
2886 {
2887 struct btrfs_multi_bio *multi = bio->bi_private;
2888 int is_orig_bio = 0;
2889
2890 if (err)
2891 atomic_inc(&multi->error);
2892
2893 if (bio == multi->orig_bio)
2894 is_orig_bio = 1;
2895
2896 if (atomic_dec_and_test(&multi->stripes_pending)) {
2897 if (!is_orig_bio) {
2898 bio_put(bio);
2899 bio = multi->orig_bio;
2900 }
2901 bio->bi_private = multi->private;
2902 bio->bi_end_io = multi->end_io;
2903 /* only send an error to the higher layers if it is
2904 * beyond the tolerance of the multi-bio
2905 */
2906 if (atomic_read(&multi->error) > multi->max_errors) {
2907 err = -EIO;
2908 } else if (err) {
2909 /*
2910 * this bio is actually up to date, we didn't
2911 * go over the max number of errors
2912 */
2913 set_bit(BIO_UPTODATE, &bio->bi_flags);
2914 err = 0;
2915 }
2916 kfree(multi);
2917
2918 bio_endio(bio, err);
2919 } else if (!is_orig_bio) {
2920 bio_put(bio);
2921 }
2922 }
2923
2924 struct async_sched {
2925 struct bio *bio;
2926 int rw;
2927 struct btrfs_fs_info *info;
2928 struct btrfs_work work;
2929 };
2930
2931 /*
2932 * see run_scheduled_bios for a description of why bios are collected for
2933 * async submit.
2934 *
2935 * This will add one bio to the pending list for a device and make sure
2936 * the work struct is scheduled.
2937 */
2938 static noinline int schedule_bio(struct btrfs_root *root,
2939 struct btrfs_device *device,
2940 int rw, struct bio *bio)
2941 {
2942 int should_queue = 1;
2943 struct btrfs_pending_bios *pending_bios;
2944
2945 /* don't bother with additional async steps for reads, right now */
2946 if (!(rw & REQ_WRITE)) {
2947 bio_get(bio);
2948 submit_bio(rw, bio);
2949 bio_put(bio);
2950 return 0;
2951 }
2952
2953 /*
2954 * nr_async_bios allows us to reliably return congestion to the
2955 * higher layers. Otherwise, the async bio makes it appear we have
2956 * made progress against dirty pages when we've really just put it
2957 * on a queue for later
2958 */
2959 atomic_inc(&root->fs_info->nr_async_bios);
2960 WARN_ON(bio->bi_next);
2961 bio->bi_next = NULL;
2962 bio->bi_rw |= rw;
2963
2964 spin_lock(&device->io_lock);
2965 if (bio->bi_rw & REQ_SYNC)
2966 pending_bios = &device->pending_sync_bios;
2967 else
2968 pending_bios = &device->pending_bios;
2969
2970 if (pending_bios->tail)
2971 pending_bios->tail->bi_next = bio;
2972
2973 pending_bios->tail = bio;
2974 if (!pending_bios->head)
2975 pending_bios->head = bio;
2976 if (device->running_pending)
2977 should_queue = 0;
2978
2979 spin_unlock(&device->io_lock);
2980
2981 if (should_queue)
2982 btrfs_queue_worker(&root->fs_info->submit_workers,
2983 &device->work);
2984 return 0;
2985 }
2986
2987 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
2988 int mirror_num, int async_submit)
2989 {
2990 struct btrfs_mapping_tree *map_tree;
2991 struct btrfs_device *dev;
2992 struct bio *first_bio = bio;
2993 u64 logical = (u64)bio->bi_sector << 9;
2994 u64 length = 0;
2995 u64 map_length;
2996 struct btrfs_multi_bio *multi = NULL;
2997 int ret;
2998 int dev_nr = 0;
2999 int total_devs = 1;
3000
3001 length = bio->bi_size;
3002 map_tree = &root->fs_info->mapping_tree;
3003 map_length = length;
3004
3005 ret = btrfs_map_block(map_tree, rw, logical, &map_length, &multi,
3006 mirror_num);
3007 BUG_ON(ret);
3008
3009 total_devs = multi->num_stripes;
3010 if (map_length < length) {
3011 printk(KERN_CRIT "mapping failed logical %llu bio len %llu "
3012 "len %llu\n", (unsigned long long)logical,
3013 (unsigned long long)length,
3014 (unsigned long long)map_length);
3015 BUG();
3016 }
3017 multi->end_io = first_bio->bi_end_io;
3018 multi->private = first_bio->bi_private;
3019 multi->orig_bio = first_bio;
3020 atomic_set(&multi->stripes_pending, multi->num_stripes);
3021
3022 while (dev_nr < total_devs) {
3023 if (total_devs > 1) {
3024 if (dev_nr < total_devs - 1) {
3025 bio = bio_clone(first_bio, GFP_NOFS);
3026 BUG_ON(!bio);
3027 } else {
3028 bio = first_bio;
3029 }
3030 bio->bi_private = multi;
3031 bio->bi_end_io = end_bio_multi_stripe;
3032 }
3033 bio->bi_sector = multi->stripes[dev_nr].physical >> 9;
3034 dev = multi->stripes[dev_nr].dev;
3035 BUG_ON(rw == WRITE && !dev->writeable);
3036 if (dev && dev->bdev) {
3037 bio->bi_bdev = dev->bdev;
3038 if (async_submit)
3039 schedule_bio(root, dev, rw, bio);
3040 else
3041 submit_bio(rw, bio);
3042 } else {
3043 bio->bi_bdev = root->fs_info->fs_devices->latest_bdev;
3044 bio->bi_sector = logical >> 9;
3045 bio_endio(bio, -EIO);
3046 }
3047 dev_nr++;
3048 }
3049 if (total_devs == 1)
3050 kfree(multi);
3051 return 0;
3052 }
3053
3054 struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
3055 u8 *uuid, u8 *fsid)
3056 {
3057 struct btrfs_device *device;
3058 struct btrfs_fs_devices *cur_devices;
3059
3060 cur_devices = root->fs_info->fs_devices;
3061 while (cur_devices) {
3062 if (!fsid ||
3063 !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
3064 device = __find_device(&cur_devices->devices,
3065 devid, uuid);
3066 if (device)
3067 return device;
3068 }
3069 cur_devices = cur_devices->seed;
3070 }
3071 return NULL;
3072 }
3073
3074 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
3075 u64 devid, u8 *dev_uuid)
3076 {
3077 struct btrfs_device *device;
3078 struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
3079
3080 device = kzalloc(sizeof(*device), GFP_NOFS);
3081 if (!device)
3082 return NULL;
3083 list_add(&device->dev_list,
3084 &fs_devices->devices);
3085 device->barriers = 1;
3086 device->dev_root = root->fs_info->dev_root;
3087 device->devid = devid;
3088 device->work.func = pending_bios_fn;
3089 device->fs_devices = fs_devices;
3090 fs_devices->num_devices++;
3091 spin_lock_init(&device->io_lock);
3092 INIT_LIST_HEAD(&device->dev_alloc_list);
3093 memcpy(device->uuid, dev_uuid, BTRFS_UUID_SIZE);
3094 return device;
3095 }
3096
3097 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
3098 struct extent_buffer *leaf,
3099 struct btrfs_chunk *chunk)
3100 {
3101 struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
3102 struct map_lookup *map;
3103 struct extent_map *em;
3104 u64 logical;
3105 u64 length;
3106 u64 devid;
3107 u8 uuid[BTRFS_UUID_SIZE];
3108 int num_stripes;
3109 int ret;
3110 int i;
3111
3112 logical = key->offset;
3113 length = btrfs_chunk_length(leaf, chunk);
3114
3115 read_lock(&map_tree->map_tree.lock);
3116 em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
3117 read_unlock(&map_tree->map_tree.lock);
3118
3119 /* already mapped? */
3120 if (em && em->start <= logical && em->start + em->len > logical) {
3121 free_extent_map(em);
3122 return 0;
3123 } else if (em) {
3124 free_extent_map(em);
3125 }
3126
3127 em = alloc_extent_map(GFP_NOFS);
3128 if (!em)
3129 return -ENOMEM;
3130 num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3131 map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
3132 if (!map) {
3133 free_extent_map(em);
3134 return -ENOMEM;
3135 }
3136
3137 em->bdev = (struct block_device *)map;
3138 em->start = logical;
3139 em->len = length;
3140 em->block_start = 0;
3141 em->block_len = em->len;
3142
3143 map->num_stripes = num_stripes;
3144 map->io_width = btrfs_chunk_io_width(leaf, chunk);
3145 map->io_align = btrfs_chunk_io_align(leaf, chunk);
3146 map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
3147 map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
3148 map->type = btrfs_chunk_type(leaf, chunk);
3149 map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
3150 for (i = 0; i < num_stripes; i++) {
3151 map->stripes[i].physical =
3152 btrfs_stripe_offset_nr(leaf, chunk, i);
3153 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
3154 read_extent_buffer(leaf, uuid, (unsigned long)
3155 btrfs_stripe_dev_uuid_nr(chunk, i),
3156 BTRFS_UUID_SIZE);
3157 map->stripes[i].dev = btrfs_find_device(root, devid, uuid,
3158 NULL);
3159 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
3160 kfree(map);
3161 free_extent_map(em);
3162 return -EIO;
3163 }
3164 if (!map->stripes[i].dev) {
3165 map->stripes[i].dev =
3166 add_missing_dev(root, devid, uuid);
3167 if (!map->stripes[i].dev) {
3168 kfree(map);
3169 free_extent_map(em);
3170 return -EIO;
3171 }
3172 }
3173 map->stripes[i].dev->in_fs_metadata = 1;
3174 }
3175
3176 write_lock(&map_tree->map_tree.lock);
3177 ret = add_extent_mapping(&map_tree->map_tree, em);
3178 write_unlock(&map_tree->map_tree.lock);
3179 BUG_ON(ret);
3180 free_extent_map(em);
3181
3182 return 0;
3183 }
3184
3185 static int fill_device_from_item(struct extent_buffer *leaf,
3186 struct btrfs_dev_item *dev_item,
3187 struct btrfs_device *device)
3188 {
3189 unsigned long ptr;
3190
3191 device->devid = btrfs_device_id(leaf, dev_item);
3192 device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
3193 device->total_bytes = device->disk_total_bytes;
3194 device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
3195 device->type = btrfs_device_type(leaf, dev_item);
3196 device->io_align = btrfs_device_io_align(leaf, dev_item);
3197 device->io_width = btrfs_device_io_width(leaf, dev_item);
3198 device->sector_size = btrfs_device_sector_size(leaf, dev_item);
3199
3200 ptr = (unsigned long)btrfs_device_uuid(dev_item);
3201 read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
3202
3203 return 0;
3204 }
3205
3206 static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
3207 {
3208 struct btrfs_fs_devices *fs_devices;
3209 int ret;
3210
3211 mutex_lock(&uuid_mutex);
3212
3213 fs_devices = root->fs_info->fs_devices->seed;
3214 while (fs_devices) {
3215 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
3216 ret = 0;
3217 goto out;
3218 }
3219 fs_devices = fs_devices->seed;
3220 }
3221
3222 fs_devices = find_fsid(fsid);
3223 if (!fs_devices) {
3224 ret = -ENOENT;
3225 goto out;
3226 }
3227
3228 fs_devices = clone_fs_devices(fs_devices);
3229 if (IS_ERR(fs_devices)) {
3230 ret = PTR_ERR(fs_devices);
3231 goto out;
3232 }
3233
3234 ret = __btrfs_open_devices(fs_devices, FMODE_READ,
3235 root->fs_info->bdev_holder);
3236 if (ret)
3237 goto out;
3238
3239 if (!fs_devices->seeding) {
3240 __btrfs_close_devices(fs_devices);
3241 free_fs_devices(fs_devices);
3242 ret = -EINVAL;
3243 goto out;
3244 }
3245
3246 fs_devices->seed = root->fs_info->fs_devices->seed;
3247 root->fs_info->fs_devices->seed = fs_devices;
3248 out:
3249 mutex_unlock(&uuid_mutex);
3250 return ret;
3251 }
3252
3253 static int read_one_dev(struct btrfs_root *root,
3254 struct extent_buffer *leaf,
3255 struct btrfs_dev_item *dev_item)
3256 {
3257 struct btrfs_device *device;
3258 u64 devid;
3259 int ret;
3260 u8 fs_uuid[BTRFS_UUID_SIZE];
3261 u8 dev_uuid[BTRFS_UUID_SIZE];
3262
3263 devid = btrfs_device_id(leaf, dev_item);
3264 read_extent_buffer(leaf, dev_uuid,
3265 (unsigned long)btrfs_device_uuid(dev_item),
3266 BTRFS_UUID_SIZE);
3267 read_extent_buffer(leaf, fs_uuid,
3268 (unsigned long)btrfs_device_fsid(dev_item),
3269 BTRFS_UUID_SIZE);
3270
3271 if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
3272 ret = open_seed_devices(root, fs_uuid);
3273 if (ret && !btrfs_test_opt(root, DEGRADED))
3274 return ret;
3275 }
3276
3277 device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
3278 if (!device || !device->bdev) {
3279 if (!btrfs_test_opt(root, DEGRADED))
3280 return -EIO;
3281
3282 if (!device) {
3283 printk(KERN_WARNING "warning devid %llu missing\n",
3284 (unsigned long long)devid);
3285 device = add_missing_dev(root, devid, dev_uuid);
3286 if (!device)
3287 return -ENOMEM;
3288 }
3289 }
3290
3291 if (device->fs_devices != root->fs_info->fs_devices) {
3292 BUG_ON(device->writeable);
3293 if (device->generation !=
3294 btrfs_device_generation(leaf, dev_item))
3295 return -EINVAL;
3296 }
3297
3298 fill_device_from_item(leaf, dev_item, device);
3299 device->dev_root = root->fs_info->dev_root;
3300 device->in_fs_metadata = 1;
3301 if (device->writeable)
3302 device->fs_devices->total_rw_bytes += device->total_bytes;
3303 ret = 0;
3304 return ret;
3305 }
3306
3307 int btrfs_read_super_device(struct btrfs_root *root, struct extent_buffer *buf)
3308 {
3309 struct btrfs_dev_item *dev_item;
3310
3311 dev_item = (struct btrfs_dev_item *)offsetof(struct btrfs_super_block,
3312 dev_item);
3313 return read_one_dev(root, buf, dev_item);
3314 }
3315
3316 int btrfs_read_sys_array(struct btrfs_root *root)
3317 {
3318 struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
3319 struct extent_buffer *sb;
3320 struct btrfs_disk_key *disk_key;
3321 struct btrfs_chunk *chunk;
3322 u8 *ptr;
3323 unsigned long sb_ptr;
3324 int ret = 0;
3325 u32 num_stripes;
3326 u32 array_size;
3327 u32 len = 0;
3328 u32 cur;
3329 struct btrfs_key key;
3330
3331 sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
3332 BTRFS_SUPER_INFO_SIZE);
3333 if (!sb)
3334 return -ENOMEM;
3335 btrfs_set_buffer_uptodate(sb);
3336 btrfs_set_buffer_lockdep_class(sb, 0);
3337
3338 write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
3339 array_size = btrfs_super_sys_array_size(super_copy);
3340
3341 ptr = super_copy->sys_chunk_array;
3342 sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
3343 cur = 0;
3344
3345 while (cur < array_size) {
3346 disk_key = (struct btrfs_disk_key *)ptr;
3347 btrfs_disk_key_to_cpu(&key, disk_key);
3348
3349 len = sizeof(*disk_key); ptr += len;
3350 sb_ptr += len;
3351 cur += len;
3352
3353 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
3354 chunk = (struct btrfs_chunk *)sb_ptr;
3355 ret = read_one_chunk(root, &key, sb, chunk);
3356 if (ret)
3357 break;
3358 num_stripes = btrfs_chunk_num_stripes(sb, chunk);
3359 len = btrfs_chunk_item_size(num_stripes);
3360 } else {
3361 ret = -EIO;
3362 break;
3363 }
3364 ptr += len;
3365 sb_ptr += len;
3366 cur += len;
3367 }
3368 free_extent_buffer(sb);
3369 return ret;
3370 }
3371
3372 int btrfs_read_chunk_tree(struct btrfs_root *root)
3373 {
3374 struct btrfs_path *path;
3375 struct extent_buffer *leaf;
3376 struct btrfs_key key;
3377 struct btrfs_key found_key;
3378 int ret;
3379 int slot;
3380
3381 root = root->fs_info->chunk_root;
3382
3383 path = btrfs_alloc_path();
3384 if (!path)
3385 return -ENOMEM;
3386
3387 /* first we search for all of the device items, and then we
3388 * read in all of the chunk items. This way we can create chunk
3389 * mappings that reference all of the devices that are afound
3390 */
3391 key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
3392 key.offset = 0;
3393 key.type = 0;
3394 again:
3395 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3396 if (ret < 0)
3397 goto error;
3398 while (1) {
3399 leaf = path->nodes[0];
3400 slot = path->slots[0];
3401 if (slot >= btrfs_header_nritems(leaf)) {
3402 ret = btrfs_next_leaf(root, path);
3403 if (ret == 0)
3404 continue;
3405 if (ret < 0)
3406 goto error;
3407 break;
3408 }
3409 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3410 if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
3411 if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
3412 break;
3413 if (found_key.type == BTRFS_DEV_ITEM_KEY) {
3414 struct btrfs_dev_item *dev_item;
3415 dev_item = btrfs_item_ptr(leaf, slot,
3416 struct btrfs_dev_item);
3417 ret = read_one_dev(root, leaf, dev_item);
3418 if (ret)
3419 goto error;
3420 }
3421 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
3422 struct btrfs_chunk *chunk;
3423 chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
3424 ret = read_one_chunk(root, &found_key, leaf, chunk);
3425 if (ret)
3426 goto error;
3427 }
3428 path->slots[0]++;
3429 }
3430 if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
3431 key.objectid = 0;
3432 btrfs_release_path(root, path);
3433 goto again;
3434 }
3435 ret = 0;
3436 error:
3437 btrfs_free_path(path);
3438 return ret;
3439 }
Tomato firmware and modifications.