btrfs: drop unused parameter from btrfs_release_path
[linux-2.6.git] / fs / btrfs / volumes.c
1 /*
2  * Copyright (C) 2007 Oracle.  All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public
6  * License v2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public
14  * License along with this program; if not, write to the
15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16  * Boston, MA 021110-1307, USA.
17  */
18 #include <linux/sched.h>
19 #include <linux/bio.h>
20 #include <linux/slab.h>
21 #include <linux/buffer_head.h>
22 #include <linux/blkdev.h>
23 #include <linux/random.h>
24 #include <linux/iocontext.h>
25 #include <linux/capability.h>
26 #include <asm/div64.h>
27 #include "compat.h"
28 #include "ctree.h"
29 #include "extent_map.h"
30 #include "disk-io.h"
31 #include "transaction.h"
32 #include "print-tree.h"
33 #include "volumes.h"
34 #include "async-thread.h"
35
36 static int init_first_rw_device(struct btrfs_trans_handle *trans,
37                                 struct btrfs_root *root,
38                                 struct btrfs_device *device);
39 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
40
41 #define map_lookup_size(n) (sizeof(struct map_lookup) + \
42                             (sizeof(struct btrfs_bio_stripe) * (n)))
43
44 static DEFINE_MUTEX(uuid_mutex);
45 static LIST_HEAD(fs_uuids);
46
47 void btrfs_lock_volumes(void)
48 {
49         mutex_lock(&uuid_mutex);
50 }
51
52 void btrfs_unlock_volumes(void)
53 {
54         mutex_unlock(&uuid_mutex);
55 }
56
57 static void lock_chunks(struct btrfs_root *root)
58 {
59         mutex_lock(&root->fs_info->chunk_mutex);
60 }
61
62 static void unlock_chunks(struct btrfs_root *root)
63 {
64         mutex_unlock(&root->fs_info->chunk_mutex);
65 }
66
67 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
68 {
69         struct btrfs_device *device;
70         WARN_ON(fs_devices->opened);
71         while (!list_empty(&fs_devices->devices)) {
72                 device = list_entry(fs_devices->devices.next,
73                                     struct btrfs_device, dev_list);
74                 list_del(&device->dev_list);
75                 kfree(device->name);
76                 kfree(device);
77         }
78         kfree(fs_devices);
79 }
80
81 int btrfs_cleanup_fs_uuids(void)
82 {
83         struct btrfs_fs_devices *fs_devices;
84
85         while (!list_empty(&fs_uuids)) {
86                 fs_devices = list_entry(fs_uuids.next,
87                                         struct btrfs_fs_devices, list);
88                 list_del(&fs_devices->list);
89                 free_fs_devices(fs_devices);
90         }
91         return 0;
92 }
93
94 static noinline struct btrfs_device *__find_device(struct list_head *head,
95                                                    u64 devid, u8 *uuid)
96 {
97         struct btrfs_device *dev;
98
99         list_for_each_entry(dev, head, dev_list) {
100                 if (dev->devid == devid &&
101                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
102                         return dev;
103                 }
104         }
105         return NULL;
106 }
107
108 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
109 {
110         struct btrfs_fs_devices *fs_devices;
111
112         list_for_each_entry(fs_devices, &fs_uuids, list) {
113                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
114                         return fs_devices;
115         }
116         return NULL;
117 }
118
119 static void requeue_list(struct btrfs_pending_bios *pending_bios,
120                         struct bio *head, struct bio *tail)
121 {
122
123         struct bio *old_head;
124
125         old_head = pending_bios->head;
126         pending_bios->head = head;
127         if (pending_bios->tail)
128                 tail->bi_next = old_head;
129         else
130                 pending_bios->tail = tail;
131 }
132
133 /*
134  * we try to collect pending bios for a device so we don't get a large
135  * number of procs sending bios down to the same device.  This greatly
136  * improves the schedulers ability to collect and merge the bios.
137  *
138  * But, it also turns into a long list of bios to process and that is sure
139  * to eventually make the worker thread block.  The solution here is to
140  * make some progress and then put this work struct back at the end of
141  * the list if the block device is congested.  This way, multiple devices
142  * can make progress from a single worker thread.
143  */
144 static noinline int run_scheduled_bios(struct btrfs_device *device)
145 {
146         struct bio *pending;
147         struct backing_dev_info *bdi;
148         struct btrfs_fs_info *fs_info;
149         struct btrfs_pending_bios *pending_bios;
150         struct bio *tail;
151         struct bio *cur;
152         int again = 0;
153         unsigned long num_run;
154         unsigned long batch_run = 0;
155         unsigned long limit;
156         unsigned long last_waited = 0;
157         int force_reg = 0;
158         struct blk_plug plug;
159
160         /*
161          * this function runs all the bios we've collected for
162          * a particular device.  We don't want to wander off to
163          * another device without first sending all of these down.
164          * So, setup a plug here and finish it off before we return
165          */
166         blk_start_plug(&plug);
167
168         bdi = blk_get_backing_dev_info(device->bdev);
169         fs_info = device->dev_root->fs_info;
170         limit = btrfs_async_submit_limit(fs_info);
171         limit = limit * 2 / 3;
172
173 loop:
174         spin_lock(&device->io_lock);
175
176 loop_lock:
177         num_run = 0;
178
179         /* take all the bios off the list at once and process them
180          * later on (without the lock held).  But, remember the
181          * tail and other pointers so the bios can be properly reinserted
182          * into the list if we hit congestion
183          */
184         if (!force_reg && device->pending_sync_bios.head) {
185                 pending_bios = &device->pending_sync_bios;
186                 force_reg = 1;
187         } else {
188                 pending_bios = &device->pending_bios;
189                 force_reg = 0;
190         }
191
192         pending = pending_bios->head;
193         tail = pending_bios->tail;
194         WARN_ON(pending && !tail);
195
196         /*
197          * if pending was null this time around, no bios need processing
198          * at all and we can stop.  Otherwise it'll loop back up again
199          * and do an additional check so no bios are missed.
200          *
201          * device->running_pending is used to synchronize with the
202          * schedule_bio code.
203          */
204         if (device->pending_sync_bios.head == NULL &&
205             device->pending_bios.head == NULL) {
206                 again = 0;
207                 device->running_pending = 0;
208         } else {
209                 again = 1;
210                 device->running_pending = 1;
211         }
212
213         pending_bios->head = NULL;
214         pending_bios->tail = NULL;
215
216         spin_unlock(&device->io_lock);
217
218         while (pending) {
219
220                 rmb();
221                 /* we want to work on both lists, but do more bios on the
222                  * sync list than the regular list
223                  */
224                 if ((num_run > 32 &&
225                     pending_bios != &device->pending_sync_bios &&
226                     device->pending_sync_bios.head) ||
227                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
228                     device->pending_bios.head)) {
229                         spin_lock(&device->io_lock);
230                         requeue_list(pending_bios, pending, tail);
231                         goto loop_lock;
232                 }
233
234                 cur = pending;
235                 pending = pending->bi_next;
236                 cur->bi_next = NULL;
237                 atomic_dec(&fs_info->nr_async_bios);
238
239                 if (atomic_read(&fs_info->nr_async_bios) < limit &&
240                     waitqueue_active(&fs_info->async_submit_wait))
241                         wake_up(&fs_info->async_submit_wait);
242
243                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
244
245                 submit_bio(cur->bi_rw, cur);
246                 num_run++;
247                 batch_run++;
248                 if (need_resched())
249                         cond_resched();
250
251                 /*
252                  * we made progress, there is more work to do and the bdi
253                  * is now congested.  Back off and let other work structs
254                  * run instead
255                  */
256                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
257                     fs_info->fs_devices->open_devices > 1) {
258                         struct io_context *ioc;
259
260                         ioc = current->io_context;
261
262                         /*
263                          * the main goal here is that we don't want to
264                          * block if we're going to be able to submit
265                          * more requests without blocking.
266                          *
267                          * This code does two great things, it pokes into
268                          * the elevator code from a filesystem _and_
269                          * it makes assumptions about how batching works.
270                          */
271                         if (ioc && ioc->nr_batch_requests > 0 &&
272                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
273                             (last_waited == 0 ||
274                              ioc->last_waited == last_waited)) {
275                                 /*
276                                  * we want to go through our batch of
277                                  * requests and stop.  So, we copy out
278                                  * the ioc->last_waited time and test
279                                  * against it before looping
280                                  */
281                                 last_waited = ioc->last_waited;
282                                 if (need_resched())
283                                         cond_resched();
284                                 continue;
285                         }
286                         spin_lock(&device->io_lock);
287                         requeue_list(pending_bios, pending, tail);
288                         device->running_pending = 1;
289
290                         spin_unlock(&device->io_lock);
291                         btrfs_requeue_work(&device->work);
292                         goto done;
293                 }
294         }
295
296         cond_resched();
297         if (again)
298                 goto loop;
299
300         spin_lock(&device->io_lock);
301         if (device->pending_bios.head || device->pending_sync_bios.head)
302                 goto loop_lock;
303         spin_unlock(&device->io_lock);
304
305 done:
306         blk_finish_plug(&plug);
307         return 0;
308 }
309
310 static void pending_bios_fn(struct btrfs_work *work)
311 {
312         struct btrfs_device *device;
313
314         device = container_of(work, struct btrfs_device, work);
315         run_scheduled_bios(device);
316 }
317
318 static noinline int device_list_add(const char *path,
319                            struct btrfs_super_block *disk_super,
320                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
321 {
322         struct btrfs_device *device;
323         struct btrfs_fs_devices *fs_devices;
324         u64 found_transid = btrfs_super_generation(disk_super);
325         char *name;
326
327         fs_devices = find_fsid(disk_super->fsid);
328         if (!fs_devices) {
329                 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
330                 if (!fs_devices)
331                         return -ENOMEM;
332                 INIT_LIST_HEAD(&fs_devices->devices);
333                 INIT_LIST_HEAD(&fs_devices->alloc_list);
334                 list_add(&fs_devices->list, &fs_uuids);
335                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
336                 fs_devices->latest_devid = devid;
337                 fs_devices->latest_trans = found_transid;
338                 mutex_init(&fs_devices->device_list_mutex);
339                 device = NULL;
340         } else {
341                 device = __find_device(&fs_devices->devices, devid,
342                                        disk_super->dev_item.uuid);
343         }
344         if (!device) {
345                 if (fs_devices->opened)
346                         return -EBUSY;
347
348                 device = kzalloc(sizeof(*device), GFP_NOFS);
349                 if (!device) {
350                         /* we can safely leave the fs_devices entry around */
351                         return -ENOMEM;
352                 }
353                 device->devid = devid;
354                 device->work.func = pending_bios_fn;
355                 memcpy(device->uuid, disk_super->dev_item.uuid,
356                        BTRFS_UUID_SIZE);
357                 spin_lock_init(&device->io_lock);
358                 device->name = kstrdup(path, GFP_NOFS);
359                 if (!device->name) {
360                         kfree(device);
361                         return -ENOMEM;
362                 }
363                 INIT_LIST_HEAD(&device->dev_alloc_list);
364
365                 mutex_lock(&fs_devices->device_list_mutex);
366                 list_add(&device->dev_list, &fs_devices->devices);
367                 mutex_unlock(&fs_devices->device_list_mutex);
368
369                 device->fs_devices = fs_devices;
370                 fs_devices->num_devices++;
371         } else if (!device->name || strcmp(device->name, path)) {
372                 name = kstrdup(path, GFP_NOFS);
373                 if (!name)
374                         return -ENOMEM;
375                 kfree(device->name);
376                 device->name = name;
377                 if (device->missing) {
378                         fs_devices->missing_devices--;
379                         device->missing = 0;
380                 }
381         }
382
383         if (found_transid > fs_devices->latest_trans) {
384                 fs_devices->latest_devid = devid;
385                 fs_devices->latest_trans = found_transid;
386         }
387         *fs_devices_ret = fs_devices;
388         return 0;
389 }
390
391 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
392 {
393         struct btrfs_fs_devices *fs_devices;
394         struct btrfs_device *device;
395         struct btrfs_device *orig_dev;
396
397         fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
398         if (!fs_devices)
399                 return ERR_PTR(-ENOMEM);
400
401         INIT_LIST_HEAD(&fs_devices->devices);
402         INIT_LIST_HEAD(&fs_devices->alloc_list);
403         INIT_LIST_HEAD(&fs_devices->list);
404         mutex_init(&fs_devices->device_list_mutex);
405         fs_devices->latest_devid = orig->latest_devid;
406         fs_devices->latest_trans = orig->latest_trans;
407         memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));
408
409         mutex_lock(&orig->device_list_mutex);
410         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
411                 device = kzalloc(sizeof(*device), GFP_NOFS);
412                 if (!device)
413                         goto error;
414
415                 device->name = kstrdup(orig_dev->name, GFP_NOFS);
416                 if (!device->name) {
417                         kfree(device);
418                         goto error;
419                 }
420
421                 device->devid = orig_dev->devid;
422                 device->work.func = pending_bios_fn;
423                 memcpy(device->uuid, orig_dev->uuid, sizeof(device->uuid));
424                 spin_lock_init(&device->io_lock);
425                 INIT_LIST_HEAD(&device->dev_list);
426                 INIT_LIST_HEAD(&device->dev_alloc_list);
427
428                 list_add(&device->dev_list, &fs_devices->devices);
429                 device->fs_devices = fs_devices;
430                 fs_devices->num_devices++;
431         }
432         mutex_unlock(&orig->device_list_mutex);
433         return fs_devices;
434 error:
435         mutex_unlock(&orig->device_list_mutex);
436         free_fs_devices(fs_devices);
437         return ERR_PTR(-ENOMEM);
438 }
439
440 int btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices)
441 {
442         struct btrfs_device *device, *next;
443
444         mutex_lock(&uuid_mutex);
445 again:
446         mutex_lock(&fs_devices->device_list_mutex);
447         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
448                 if (device->in_fs_metadata)
449                         continue;
450
451                 if (device->bdev) {
452                         blkdev_put(device->bdev, device->mode);
453                         device->bdev = NULL;
454                         fs_devices->open_devices--;
455                 }
456                 if (device->writeable) {
457                         list_del_init(&device->dev_alloc_list);
458                         device->writeable = 0;
459                         fs_devices->rw_devices--;
460                 }
461                 list_del_init(&device->dev_list);
462                 fs_devices->num_devices--;
463                 kfree(device->name);
464                 kfree(device);
465         }
466         mutex_unlock(&fs_devices->device_list_mutex);
467
468         if (fs_devices->seed) {
469                 fs_devices = fs_devices->seed;
470                 goto again;
471         }
472
473         mutex_unlock(&uuid_mutex);
474         return 0;
475 }
476
477 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
478 {
479         struct btrfs_device *device;
480
481         if (--fs_devices->opened > 0)
482                 return 0;
483
484         list_for_each_entry(device, &fs_devices->devices, dev_list) {
485                 if (device->bdev) {
486                         blkdev_put(device->bdev, device->mode);
487                         fs_devices->open_devices--;
488                 }
489                 if (device->writeable) {
490                         list_del_init(&device->dev_alloc_list);
491                         fs_devices->rw_devices--;
492                 }
493
494                 device->bdev = NULL;
495                 device->writeable = 0;
496                 device->in_fs_metadata = 0;
497         }
498         WARN_ON(fs_devices->open_devices);
499         WARN_ON(fs_devices->rw_devices);
500         fs_devices->opened = 0;
501         fs_devices->seeding = 0;
502
503         return 0;
504 }
505
506 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
507 {
508         struct btrfs_fs_devices *seed_devices = NULL;
509         int ret;
510
511         mutex_lock(&uuid_mutex);
512         ret = __btrfs_close_devices(fs_devices);
513         if (!fs_devices->opened) {
514                 seed_devices = fs_devices->seed;
515                 fs_devices->seed = NULL;
516         }
517         mutex_unlock(&uuid_mutex);
518
519         while (seed_devices) {
520                 fs_devices = seed_devices;
521                 seed_devices = fs_devices->seed;
522                 __btrfs_close_devices(fs_devices);
523                 free_fs_devices(fs_devices);
524         }
525         return ret;
526 }
527
528 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
529                                 fmode_t flags, void *holder)
530 {
531         struct block_device *bdev;
532         struct list_head *head = &fs_devices->devices;
533         struct btrfs_device *device;
534         struct block_device *latest_bdev = NULL;
535         struct buffer_head *bh;
536         struct btrfs_super_block *disk_super;
537         u64 latest_devid = 0;
538         u64 latest_transid = 0;
539         u64 devid;
540         int seeding = 1;
541         int ret = 0;
542
543         flags |= FMODE_EXCL;
544
545         list_for_each_entry(device, head, dev_list) {
546                 if (device->bdev)
547                         continue;
548                 if (!device->name)
549                         continue;
550
551                 bdev = blkdev_get_by_path(device->name, flags, holder);
552                 if (IS_ERR(bdev)) {
553                         printk(KERN_INFO "open %s failed\n", device->name);
554                         goto error;
555                 }
556                 set_blocksize(bdev, 4096);
557
558                 bh = btrfs_read_dev_super(bdev);
559                 if (!bh) {
560                         ret = -EINVAL;
561                         goto error_close;
562                 }
563
564                 disk_super = (struct btrfs_super_block *)bh->b_data;
565                 devid = btrfs_stack_device_id(&disk_super->dev_item);
566                 if (devid != device->devid)
567                         goto error_brelse;
568
569                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
570                            BTRFS_UUID_SIZE))
571                         goto error_brelse;
572
573                 device->generation = btrfs_super_generation(disk_super);
574                 if (!latest_transid || device->generation > latest_transid) {
575                         latest_devid = devid;
576                         latest_transid = device->generation;
577                         latest_bdev = bdev;
578                 }
579
580                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
581                         device->writeable = 0;
582                 } else {
583                         device->writeable = !bdev_read_only(bdev);
584                         seeding = 0;
585                 }
586
587                 device->bdev = bdev;
588                 device->in_fs_metadata = 0;
589                 device->mode = flags;
590
591                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
592                         fs_devices->rotating = 1;
593
594                 fs_devices->open_devices++;
595                 if (device->writeable) {
596                         fs_devices->rw_devices++;
597                         list_add(&device->dev_alloc_list,
598                                  &fs_devices->alloc_list);
599                 }
600                 continue;
601
602 error_brelse:
603                 brelse(bh);
604 error_close:
605                 blkdev_put(bdev, flags);
606 error:
607                 continue;
608         }
609         if (fs_devices->open_devices == 0) {
610                 ret = -EIO;
611                 goto out;
612         }
613         fs_devices->seeding = seeding;
614         fs_devices->opened = 1;
615         fs_devices->latest_bdev = latest_bdev;
616         fs_devices->latest_devid = latest_devid;
617         fs_devices->latest_trans = latest_transid;
618         fs_devices->total_rw_bytes = 0;
619 out:
620         return ret;
621 }
622
623 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
624                        fmode_t flags, void *holder)
625 {
626         int ret;
627
628         mutex_lock(&uuid_mutex);
629         if (fs_devices->opened) {
630                 fs_devices->opened++;
631                 ret = 0;
632         } else {
633                 ret = __btrfs_open_devices(fs_devices, flags, holder);
634         }
635         mutex_unlock(&uuid_mutex);
636         return ret;
637 }
638
639 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
640                           struct btrfs_fs_devices **fs_devices_ret)
641 {
642         struct btrfs_super_block *disk_super;
643         struct block_device *bdev;
644         struct buffer_head *bh;
645         int ret;
646         u64 devid;
647         u64 transid;
648
649         mutex_lock(&uuid_mutex);
650
651         flags |= FMODE_EXCL;
652         bdev = blkdev_get_by_path(path, flags, holder);
653
654         if (IS_ERR(bdev)) {
655                 ret = PTR_ERR(bdev);
656                 goto error;
657         }
658
659         ret = set_blocksize(bdev, 4096);
660         if (ret)
661                 goto error_close;
662         bh = btrfs_read_dev_super(bdev);
663         if (!bh) {
664                 ret = -EINVAL;
665                 goto error_close;
666         }
667         disk_super = (struct btrfs_super_block *)bh->b_data;
668         devid = btrfs_stack_device_id(&disk_super->dev_item);
669         transid = btrfs_super_generation(disk_super);
670         if (disk_super->label[0])
671                 printk(KERN_INFO "device label %s ", disk_super->label);
672         else {
673                 /* FIXME, make a readl uuid parser */
674                 printk(KERN_INFO "device fsid %llx-%llx ",
675                        *(unsigned long long *)disk_super->fsid,
676                        *(unsigned long long *)(disk_super->fsid + 8));
677         }
678         printk(KERN_CONT "devid %llu transid %llu %s\n",
679                (unsigned long long)devid, (unsigned long long)transid, path);
680         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
681
682         brelse(bh);
683 error_close:
684         blkdev_put(bdev, flags);
685 error:
686         mutex_unlock(&uuid_mutex);
687         return ret;
688 }
689
690 /* helper to account the used device space in the range */
691 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
692                                    u64 end, u64 *length)
693 {
694         struct btrfs_key key;
695         struct btrfs_root *root = device->dev_root;
696         struct btrfs_dev_extent *dev_extent;
697         struct btrfs_path *path;
698         u64 extent_end;
699         int ret;
700         int slot;
701         struct extent_buffer *l;
702
703         *length = 0;
704
705         if (start >= device->total_bytes)
706                 return 0;
707
708         path = btrfs_alloc_path();
709         if (!path)
710                 return -ENOMEM;
711         path->reada = 2;
712
713         key.objectid = device->devid;
714         key.offset = start;
715         key.type = BTRFS_DEV_EXTENT_KEY;
716
717         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
718         if (ret < 0)
719                 goto out;
720         if (ret > 0) {
721                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
722                 if (ret < 0)
723                         goto out;
724         }
725
726         while (1) {
727                 l = path->nodes[0];
728                 slot = path->slots[0];
729                 if (slot >= btrfs_header_nritems(l)) {
730                         ret = btrfs_next_leaf(root, path);
731                         if (ret == 0)
732                                 continue;
733                         if (ret < 0)
734                                 goto out;
735
736                         break;
737                 }
738                 btrfs_item_key_to_cpu(l, &key, slot);
739
740                 if (key.objectid < device->devid)
741                         goto next;
742
743                 if (key.objectid > device->devid)
744                         break;
745
746                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
747                         goto next;
748
749                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
750                 extent_end = key.offset + btrfs_dev_extent_length(l,
751                                                                   dev_extent);
752                 if (key.offset <= start && extent_end > end) {
753                         *length = end - start + 1;
754                         break;
755                 } else if (key.offset <= start && extent_end > start)
756                         *length += extent_end - start;
757                 else if (key.offset > start && extent_end <= end)
758                         *length += extent_end - key.offset;
759                 else if (key.offset > start && key.offset <= end) {
760                         *length += end - key.offset + 1;
761                         break;
762                 } else if (key.offset > end)
763                         break;
764
765 next:
766                 path->slots[0]++;
767         }
768         ret = 0;
769 out:
770         btrfs_free_path(path);
771         return ret;
772 }
773
774 /*
775  * find_free_dev_extent - find free space in the specified device
776  * @trans:      transaction handler
777  * @device:     the device which we search the free space in
778  * @num_bytes:  the size of the free space that we need
779  * @start:      store the start of the free space.
780  * @len:        the size of the free space. that we find, or the size of the max
781  *              free space if we don't find suitable free space
782  *
783  * this uses a pretty simple search, the expectation is that it is
784  * called very infrequently and that a given device has a small number
785  * of extents
786  *
787  * @start is used to store the start of the free space if we find. But if we
788  * don't find suitable free space, it will be used to store the start position
789  * of the max free space.
790  *
791  * @len is used to store the size of the free space that we find.
792  * But if we don't find suitable free space, it is used to store the size of
793  * the max free space.
794  */
795 int find_free_dev_extent(struct btrfs_trans_handle *trans,
796                          struct btrfs_device *device, u64 num_bytes,
797                          u64 *start, u64 *len)
798 {
799         struct btrfs_key key;
800         struct btrfs_root *root = device->dev_root;
801         struct btrfs_dev_extent *dev_extent;
802         struct btrfs_path *path;
803         u64 hole_size;
804         u64 max_hole_start;
805         u64 max_hole_size;
806         u64 extent_end;
807         u64 search_start;
808         u64 search_end = device->total_bytes;
809         int ret;
810         int slot;
811         struct extent_buffer *l;
812
813         /* FIXME use last free of some kind */
814
815         /* we don't want to overwrite the superblock on the drive,
816          * so we make sure to start at an offset of at least 1MB
817          */
818         search_start = 1024 * 1024;
819
820         if (root->fs_info->alloc_start + num_bytes <= search_end)
821                 search_start = max(root->fs_info->alloc_start, search_start);
822
823         max_hole_start = search_start;
824         max_hole_size = 0;
825
826         if (search_start >= search_end) {
827                 ret = -ENOSPC;
828                 goto error;
829         }
830
831         path = btrfs_alloc_path();
832         if (!path) {
833                 ret = -ENOMEM;
834                 goto error;
835         }
836         path->reada = 2;
837
838         key.objectid = device->devid;
839         key.offset = search_start;
840         key.type = BTRFS_DEV_EXTENT_KEY;
841
842         ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
843         if (ret < 0)
844                 goto out;
845         if (ret > 0) {
846                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
847                 if (ret < 0)
848                         goto out;
849         }
850
851         while (1) {
852                 l = path->nodes[0];
853                 slot = path->slots[0];
854                 if (slot >= btrfs_header_nritems(l)) {
855                         ret = btrfs_next_leaf(root, path);
856                         if (ret == 0)
857                                 continue;
858                         if (ret < 0)
859                                 goto out;
860
861                         break;
862                 }
863                 btrfs_item_key_to_cpu(l, &key, slot);
864
865                 if (key.objectid < device->devid)
866                         goto next;
867
868                 if (key.objectid > device->devid)
869                         break;
870
871                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
872                         goto next;
873
874                 if (key.offset > search_start) {
875                         hole_size = key.offset - search_start;
876
877                         if (hole_size > max_hole_size) {
878                                 max_hole_start = search_start;
879                                 max_hole_size = hole_size;
880                         }
881
882                         /*
883                          * If this free space is greater than which we need,
884                          * it must be the max free space that we have found
885                          * until now, so max_hole_start must point to the start
886                          * of this free space and the length of this free space
887                          * is stored in max_hole_size. Thus, we return
888                          * max_hole_start and max_hole_size and go back to the
889                          * caller.
890                          */
891                         if (hole_size >= num_bytes) {
892                                 ret = 0;
893                                 goto out;
894                         }
895                 }
896
897                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
898                 extent_end = key.offset + btrfs_dev_extent_length(l,
899                                                                   dev_extent);
900                 if (extent_end > search_start)
901                         search_start = extent_end;
902 next:
903                 path->slots[0]++;
904                 cond_resched();
905         }
906
907         hole_size = search_end- search_start;
908         if (hole_size > max_hole_size) {
909                 max_hole_start = search_start;
910                 max_hole_size = hole_size;
911         }
912
913         /* See above. */
914         if (hole_size < num_bytes)
915                 ret = -ENOSPC;
916         else
917                 ret = 0;
918
919 out:
920         btrfs_free_path(path);
921 error:
922         *start = max_hole_start;
923         if (len)
924                 *len = max_hole_size;
925         return ret;
926 }
927
928 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
929                           struct btrfs_device *device,
930                           u64 start)
931 {
932         int ret;
933         struct btrfs_path *path;
934         struct btrfs_root *root = device->dev_root;
935         struct btrfs_key key;
936         struct btrfs_key found_key;
937         struct extent_buffer *leaf = NULL;
938         struct btrfs_dev_extent *extent = NULL;
939
940         path = btrfs_alloc_path();
941         if (!path)
942                 return -ENOMEM;
943
944         key.objectid = device->devid;
945         key.offset = start;
946         key.type = BTRFS_DEV_EXTENT_KEY;
947
948         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
949         if (ret > 0) {
950                 ret = btrfs_previous_item(root, path, key.objectid,
951                                           BTRFS_DEV_EXTENT_KEY);
952                 BUG_ON(ret);
953                 leaf = path->nodes[0];
954                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
955                 extent = btrfs_item_ptr(leaf, path->slots[0],
956                                         struct btrfs_dev_extent);
957                 BUG_ON(found_key.offset > start || found_key.offset +
958                        btrfs_dev_extent_length(leaf, extent) < start);
959                 ret = 0;
960         } else if (ret == 0) {
961                 leaf = path->nodes[0];
962                 extent = btrfs_item_ptr(leaf, path->slots[0],
963                                         struct btrfs_dev_extent);
964         }
965         BUG_ON(ret);
966
967         if (device->bytes_used > 0)
968                 device->bytes_used -= btrfs_dev_extent_length(leaf, extent);
969         ret = btrfs_del_item(trans, root, path);
970         BUG_ON(ret);
971
972         btrfs_free_path(path);
973         return ret;
974 }
975
976 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
977                            struct btrfs_device *device,
978                            u64 chunk_tree, u64 chunk_objectid,
979                            u64 chunk_offset, u64 start, u64 num_bytes)
980 {
981         int ret;
982         struct btrfs_path *path;
983         struct btrfs_root *root = device->dev_root;
984         struct btrfs_dev_extent *extent;
985         struct extent_buffer *leaf;
986         struct btrfs_key key;
987
988         WARN_ON(!device->in_fs_metadata);
989         path = btrfs_alloc_path();
990         if (!path)
991                 return -ENOMEM;
992
993         key.objectid = device->devid;
994         key.offset = start;
995         key.type = BTRFS_DEV_EXTENT_KEY;
996         ret = btrfs_insert_empty_item(trans, root, path, &key,
997                                       sizeof(*extent));
998         BUG_ON(ret);
999
1000         leaf = path->nodes[0];
1001         extent = btrfs_item_ptr(leaf, path->slots[0],
1002                                 struct btrfs_dev_extent);
1003         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
1004         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
1005         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
1006
1007         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
1008                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
1009                     BTRFS_UUID_SIZE);
1010
1011         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
1012         btrfs_mark_buffer_dirty(leaf);
1013         btrfs_free_path(path);
1014         return ret;
1015 }
1016
1017 static noinline int find_next_chunk(struct btrfs_root *root,
1018                                     u64 objectid, u64 *offset)
1019 {
1020         struct btrfs_path *path;
1021         int ret;
1022         struct btrfs_key key;
1023         struct btrfs_chunk *chunk;
1024         struct btrfs_key found_key;
1025
1026         path = btrfs_alloc_path();
1027         BUG_ON(!path);
1028
1029         key.objectid = objectid;
1030         key.offset = (u64)-1;
1031         key.type = BTRFS_CHUNK_ITEM_KEY;
1032
1033         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1034         if (ret < 0)
1035                 goto error;
1036
1037         BUG_ON(ret == 0);
1038
1039         ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
1040         if (ret) {
1041                 *offset = 0;
1042         } else {
1043                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1044                                       path->slots[0]);
1045                 if (found_key.objectid != objectid)
1046                         *offset = 0;
1047                 else {
1048                         chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
1049                                                struct btrfs_chunk);
1050                         *offset = found_key.offset +
1051                                 btrfs_chunk_length(path->nodes[0], chunk);
1052                 }
1053         }
1054         ret = 0;
1055 error:
1056         btrfs_free_path(path);
1057         return ret;
1058 }
1059
1060 static noinline int find_next_devid(struct btrfs_root *root, u64 *objectid)
1061 {
1062         int ret;
1063         struct btrfs_key key;
1064         struct btrfs_key found_key;
1065         struct btrfs_path *path;
1066
1067         root = root->fs_info->chunk_root;
1068
1069         path = btrfs_alloc_path();
1070         if (!path)
1071                 return -ENOMEM;
1072
1073         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1074         key.type = BTRFS_DEV_ITEM_KEY;
1075         key.offset = (u64)-1;
1076
1077         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1078         if (ret < 0)
1079                 goto error;
1080
1081         BUG_ON(ret == 0);
1082
1083         ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
1084                                   BTRFS_DEV_ITEM_KEY);
1085         if (ret) {
1086                 *objectid = 1;
1087         } else {
1088                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1089                                       path->slots[0]);
1090                 *objectid = found_key.offset + 1;
1091         }
1092         ret = 0;
1093 error:
1094         btrfs_free_path(path);
1095         return ret;
1096 }
1097
1098 /*
1099  * the device information is stored in the chunk root
1100  * the btrfs_device struct should be fully filled in
1101  */
1102 int btrfs_add_device(struct btrfs_trans_handle *trans,
1103                      struct btrfs_root *root,
1104                      struct btrfs_device *device)
1105 {
1106         int ret;
1107         struct btrfs_path *path;
1108         struct btrfs_dev_item *dev_item;
1109         struct extent_buffer *leaf;
1110         struct btrfs_key key;
1111         unsigned long ptr;
1112
1113         root = root->fs_info->chunk_root;
1114
1115         path = btrfs_alloc_path();
1116         if (!path)
1117                 return -ENOMEM;
1118
1119         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1120         key.type = BTRFS_DEV_ITEM_KEY;
1121         key.offset = device->devid;
1122
1123         ret = btrfs_insert_empty_item(trans, root, path, &key,
1124                                       sizeof(*dev_item));
1125         if (ret)
1126                 goto out;
1127
1128         leaf = path->nodes[0];
1129         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1130
1131         btrfs_set_device_id(leaf, dev_item, device->devid);
1132         btrfs_set_device_generation(leaf, dev_item, 0);
1133         btrfs_set_device_type(leaf, dev_item, device->type);
1134         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1135         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1136         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1137         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
1138         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1139         btrfs_set_device_group(leaf, dev_item, 0);
1140         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1141         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1142         btrfs_set_device_start_offset(leaf, dev_item, 0);
1143
1144         ptr = (unsigned long)btrfs_device_uuid(dev_item);
1145         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1146         ptr = (unsigned long)btrfs_device_fsid(dev_item);
1147         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1148         btrfs_mark_buffer_dirty(leaf);
1149
1150         ret = 0;
1151 out:
1152         btrfs_free_path(path);
1153         return ret;
1154 }
1155
1156 static int btrfs_rm_dev_item(struct btrfs_root *root,
1157                              struct btrfs_device *device)
1158 {
1159         int ret;
1160         struct btrfs_path *path;
1161         struct btrfs_key key;
1162         struct btrfs_trans_handle *trans;
1163
1164         root = root->fs_info->chunk_root;
1165
1166         path = btrfs_alloc_path();
1167         if (!path)
1168                 return -ENOMEM;
1169
1170         trans = btrfs_start_transaction(root, 0);
1171         if (IS_ERR(trans)) {
1172                 btrfs_free_path(path);
1173                 return PTR_ERR(trans);
1174         }
1175         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1176         key.type = BTRFS_DEV_ITEM_KEY;
1177         key.offset = device->devid;
1178         lock_chunks(root);
1179
1180         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1181         if (ret < 0)
1182                 goto out;
1183
1184         if (ret > 0) {
1185                 ret = -ENOENT;
1186                 goto out;
1187         }
1188
1189         ret = btrfs_del_item(trans, root, path);
1190         if (ret)
1191                 goto out;
1192 out:
1193         btrfs_free_path(path);
1194         unlock_chunks(root);
1195         btrfs_commit_transaction(trans, root);
1196         return ret;
1197 }
1198
1199 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1200 {
1201         struct btrfs_device *device;
1202         struct btrfs_device *next_device;
1203         struct block_device *bdev;
1204         struct buffer_head *bh = NULL;
1205         struct btrfs_super_block *disk_super;
1206         u64 all_avail;
1207         u64 devid;
1208         u64 num_devices;
1209         u8 *dev_uuid;
1210         int ret = 0;
1211
1212         mutex_lock(&uuid_mutex);
1213         mutex_lock(&root->fs_info->volume_mutex);
1214
1215         all_avail = root->fs_info->avail_data_alloc_bits |
1216                 root->fs_info->avail_system_alloc_bits |
1217                 root->fs_info->avail_metadata_alloc_bits;
1218
1219         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) &&
1220             root->fs_info->fs_devices->num_devices <= 4) {
1221                 printk(KERN_ERR "btrfs: unable to go below four devices "
1222                        "on raid10\n");
1223                 ret = -EINVAL;
1224                 goto out;
1225         }
1226
1227         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) &&
1228             root->fs_info->fs_devices->num_devices <= 2) {
1229                 printk(KERN_ERR "btrfs: unable to go below two "
1230                        "devices on raid1\n");
1231                 ret = -EINVAL;
1232                 goto out;
1233         }
1234
1235         if (strcmp(device_path, "missing") == 0) {
1236                 struct list_head *devices;
1237                 struct btrfs_device *tmp;
1238
1239                 device = NULL;
1240                 devices = &root->fs_info->fs_devices->devices;
1241                 mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1242                 list_for_each_entry(tmp, devices, dev_list) {
1243                         if (tmp->in_fs_metadata && !tmp->bdev) {
1244                                 device = tmp;
1245                                 break;
1246                         }
1247                 }
1248                 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1249                 bdev = NULL;
1250                 bh = NULL;
1251                 disk_super = NULL;
1252                 if (!device) {
1253                         printk(KERN_ERR "btrfs: no missing devices found to "
1254                                "remove\n");
1255                         goto out;
1256                 }
1257         } else {
1258                 bdev = blkdev_get_by_path(device_path, FMODE_READ | FMODE_EXCL,
1259                                           root->fs_info->bdev_holder);
1260                 if (IS_ERR(bdev)) {
1261                         ret = PTR_ERR(bdev);
1262                         goto out;
1263                 }
1264
1265                 set_blocksize(bdev, 4096);
1266                 bh = btrfs_read_dev_super(bdev);
1267                 if (!bh) {
1268                         ret = -EINVAL;
1269                         goto error_close;
1270                 }
1271                 disk_super = (struct btrfs_super_block *)bh->b_data;
1272                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1273                 dev_uuid = disk_super->dev_item.uuid;
1274                 device = btrfs_find_device(root, devid, dev_uuid,
1275                                            disk_super->fsid);
1276                 if (!device) {
1277                         ret = -ENOENT;
1278                         goto error_brelse;
1279                 }
1280         }
1281
1282         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1283                 printk(KERN_ERR "btrfs: unable to remove the only writeable "
1284                        "device\n");
1285                 ret = -EINVAL;
1286                 goto error_brelse;
1287         }
1288
1289         if (device->writeable) {
1290                 list_del_init(&device->dev_alloc_list);
1291                 root->fs_info->fs_devices->rw_devices--;
1292         }
1293
1294         ret = btrfs_shrink_device(device, 0);
1295         if (ret)
1296                 goto error_undo;
1297
1298         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1299         if (ret)
1300                 goto error_undo;
1301
1302         device->in_fs_metadata = 0;
1303
1304         /*
1305          * the device list mutex makes sure that we don't change
1306          * the device list while someone else is writing out all
1307          * the device supers.
1308          */
1309         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1310         list_del_init(&device->dev_list);
1311         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1312
1313         device->fs_devices->num_devices--;
1314
1315         if (device->missing)
1316                 root->fs_info->fs_devices->missing_devices--;
1317
1318         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1319                                  struct btrfs_device, dev_list);
1320         if (device->bdev == root->fs_info->sb->s_bdev)
1321                 root->fs_info->sb->s_bdev = next_device->bdev;
1322         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1323                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1324
1325         if (device->bdev) {
1326                 blkdev_put(device->bdev, device->mode);
1327                 device->bdev = NULL;
1328                 device->fs_devices->open_devices--;
1329         }
1330
1331         num_devices = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
1332         btrfs_set_super_num_devices(&root->fs_info->super_copy, num_devices);
1333
1334         if (device->fs_devices->open_devices == 0) {
1335                 struct btrfs_fs_devices *fs_devices;
1336                 fs_devices = root->fs_info->fs_devices;
1337                 while (fs_devices) {
1338                         if (fs_devices->seed == device->fs_devices)
1339                                 break;
1340                         fs_devices = fs_devices->seed;
1341                 }
1342                 fs_devices->seed = device->fs_devices->seed;
1343                 device->fs_devices->seed = NULL;
1344                 __btrfs_close_devices(device->fs_devices);
1345                 free_fs_devices(device->fs_devices);
1346         }
1347
1348         /*
1349          * at this point, the device is zero sized.  We want to
1350          * remove it from the devices list and zero out the old super
1351          */
1352         if (device->writeable) {
1353                 /* make sure this device isn't detected as part of
1354                  * the FS anymore
1355                  */
1356                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1357                 set_buffer_dirty(bh);
1358                 sync_dirty_buffer(bh);
1359         }
1360
1361         kfree(device->name);
1362         kfree(device);
1363         ret = 0;
1364
1365 error_brelse:
1366         brelse(bh);
1367 error_close:
1368         if (bdev)
1369                 blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
1370 out:
1371         mutex_unlock(&root->fs_info->volume_mutex);
1372         mutex_unlock(&uuid_mutex);
1373         return ret;
1374 error_undo:
1375         if (device->writeable) {
1376                 list_add(&device->dev_alloc_list,
1377                          &root->fs_info->fs_devices->alloc_list);
1378                 root->fs_info->fs_devices->rw_devices++;
1379         }
1380         goto error_brelse;
1381 }
1382
1383 /*
1384  * does all the dirty work required for changing file system's UUID.
1385  */
1386 static int btrfs_prepare_sprout(struct btrfs_trans_handle *trans,
1387                                 struct btrfs_root *root)
1388 {
1389         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
1390         struct btrfs_fs_devices *old_devices;
1391         struct btrfs_fs_devices *seed_devices;
1392         struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
1393         struct btrfs_device *device;
1394         u64 super_flags;
1395
1396         BUG_ON(!mutex_is_locked(&uuid_mutex));
1397         if (!fs_devices->seeding)
1398                 return -EINVAL;
1399
1400         seed_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
1401         if (!seed_devices)
1402                 return -ENOMEM;
1403
1404         old_devices = clone_fs_devices(fs_devices);
1405         if (IS_ERR(old_devices)) {
1406                 kfree(seed_devices);
1407                 return PTR_ERR(old_devices);
1408         }
1409
1410         list_add(&old_devices->list, &fs_uuids);
1411
1412         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
1413         seed_devices->opened = 1;
1414         INIT_LIST_HEAD(&seed_devices->devices);
1415         INIT_LIST_HEAD(&seed_devices->alloc_list);
1416         mutex_init(&seed_devices->device_list_mutex);
1417         list_splice_init(&fs_devices->devices, &seed_devices->devices);
1418         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
1419         list_for_each_entry(device, &seed_devices->devices, dev_list) {
1420                 device->fs_devices = seed_devices;
1421         }
1422
1423         fs_devices->seeding = 0;
1424         fs_devices->num_devices = 0;
1425         fs_devices->open_devices = 0;
1426         fs_devices->seed = seed_devices;
1427
1428         generate_random_uuid(fs_devices->fsid);
1429         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1430         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1431         super_flags = btrfs_super_flags(disk_super) &
1432                       ~BTRFS_SUPER_FLAG_SEEDING;
1433         btrfs_set_super_flags(disk_super, super_flags);
1434
1435         return 0;
1436 }
1437
1438 /*
1439  * strore the expected generation for seed devices in device items.
1440  */
1441 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
1442                                struct btrfs_root *root)
1443 {
1444         struct btrfs_path *path;
1445         struct extent_buffer *leaf;
1446         struct btrfs_dev_item *dev_item;
1447         struct btrfs_device *device;
1448         struct btrfs_key key;
1449         u8 fs_uuid[BTRFS_UUID_SIZE];
1450         u8 dev_uuid[BTRFS_UUID_SIZE];
1451         u64 devid;
1452         int ret;
1453
1454         path = btrfs_alloc_path();
1455         if (!path)
1456                 return -ENOMEM;
1457
1458         root = root->fs_info->chunk_root;
1459         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1460         key.offset = 0;
1461         key.type = BTRFS_DEV_ITEM_KEY;
1462
1463         while (1) {
1464                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1465                 if (ret < 0)
1466                         goto error;
1467
1468                 leaf = path->nodes[0];
1469 next_slot:
1470                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1471                         ret = btrfs_next_leaf(root, path);
1472                         if (ret > 0)
1473                                 break;
1474                         if (ret < 0)
1475                                 goto error;
1476                         leaf = path->nodes[0];
1477                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1478                         btrfs_release_path(path);
1479                         continue;
1480                 }
1481
1482                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1483                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
1484                     key.type != BTRFS_DEV_ITEM_KEY)
1485                         break;
1486
1487                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
1488                                           struct btrfs_dev_item);
1489                 devid = btrfs_device_id(leaf, dev_item);
1490                 read_extent_buffer(leaf, dev_uuid,
1491                                    (unsigned long)btrfs_device_uuid(dev_item),
1492                                    BTRFS_UUID_SIZE);
1493                 read_extent_buffer(leaf, fs_uuid,
1494                                    (unsigned long)btrfs_device_fsid(dev_item),
1495                                    BTRFS_UUID_SIZE);
1496                 device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
1497                 BUG_ON(!device);
1498
1499                 if (device->fs_devices->seeding) {
1500                         btrfs_set_device_generation(leaf, dev_item,
1501                                                     device->generation);
1502                         btrfs_mark_buffer_dirty(leaf);
1503                 }
1504
1505                 path->slots[0]++;
1506                 goto next_slot;
1507         }
1508         ret = 0;
1509 error:
1510         btrfs_free_path(path);
1511         return ret;
1512 }
1513
1514 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
1515 {
1516         struct btrfs_trans_handle *trans;
1517         struct btrfs_device *device;
1518         struct block_device *bdev;
1519         struct list_head *devices;
1520         struct super_block *sb = root->fs_info->sb;
1521         u64 total_bytes;
1522         int seeding_dev = 0;
1523         int ret = 0;
1524
1525         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
1526                 return -EINVAL;
1527
1528         bdev = blkdev_get_by_path(device_path, FMODE_EXCL,
1529                                   root->fs_info->bdev_holder);
1530         if (IS_ERR(bdev))
1531                 return PTR_ERR(bdev);
1532
1533         if (root->fs_info->fs_devices->seeding) {
1534                 seeding_dev = 1;
1535                 down_write(&sb->s_umount);
1536                 mutex_lock(&uuid_mutex);
1537         }
1538
1539         filemap_write_and_wait(bdev->bd_inode->i_mapping);
1540         mutex_lock(&root->fs_info->volume_mutex);
1541
1542         devices = &root->fs_info->fs_devices->devices;
1543         /*
1544          * we have the volume lock, so we don't need the extra
1545          * device list mutex while reading the list here.
1546          */
1547         list_for_each_entry(device, devices, dev_list) {
1548                 if (device->bdev == bdev) {
1549                         ret = -EEXIST;
1550                         goto error;
1551                 }
1552         }
1553
1554         device = kzalloc(sizeof(*device), GFP_NOFS);
1555         if (!device) {
1556                 /* we can safely leave the fs_devices entry around */
1557                 ret = -ENOMEM;
1558                 goto error;
1559         }
1560
1561         device->name = kstrdup(device_path, GFP_NOFS);
1562         if (!device->name) {
1563                 kfree(device);
1564                 ret = -ENOMEM;
1565                 goto error;
1566         }
1567
1568         ret = find_next_devid(root, &device->devid);
1569         if (ret) {
1570                 kfree(device->name);
1571                 kfree(device);
1572                 goto error;
1573         }
1574
1575         trans = btrfs_start_transaction(root, 0);
1576         if (IS_ERR(trans)) {
1577                 kfree(device->name);
1578                 kfree(device);
1579                 ret = PTR_ERR(trans);
1580                 goto error;
1581         }
1582
1583         lock_chunks(root);
1584
1585         device->writeable = 1;
1586         device->work.func = pending_bios_fn;
1587         generate_random_uuid(device->uuid);
1588         spin_lock_init(&device->io_lock);
1589         device->generation = trans->transid;
1590         device->io_width = root->sectorsize;
1591         device->io_align = root->sectorsize;
1592         device->sector_size = root->sectorsize;
1593         device->total_bytes = i_size_read(bdev->bd_inode);
1594         device->disk_total_bytes = device->total_bytes;
1595         device->dev_root = root->fs_info->dev_root;
1596         device->bdev = bdev;
1597         device->in_fs_metadata = 1;
1598         device->mode = FMODE_EXCL;
1599         set_blocksize(device->bdev, 4096);
1600
1601         if (seeding_dev) {
1602                 sb->s_flags &= ~MS_RDONLY;
1603                 ret = btrfs_prepare_sprout(trans, root);
1604                 BUG_ON(ret);
1605         }
1606
1607         device->fs_devices = root->fs_info->fs_devices;
1608
1609         /*
1610          * we don't want write_supers to jump in here with our device
1611          * half setup
1612          */
1613         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1614         list_add(&device->dev_list, &root->fs_info->fs_devices->devices);
1615         list_add(&device->dev_alloc_list,
1616                  &root->fs_info->fs_devices->alloc_list);
1617         root->fs_info->fs_devices->num_devices++;
1618         root->fs_info->fs_devices->open_devices++;
1619         root->fs_info->fs_devices->rw_devices++;
1620         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
1621
1622         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
1623                 root->fs_info->fs_devices->rotating = 1;
1624
1625         total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
1626         btrfs_set_super_total_bytes(&root->fs_info->super_copy,
1627                                     total_bytes + device->total_bytes);
1628
1629         total_bytes = btrfs_super_num_devices(&root->fs_info->super_copy);
1630         btrfs_set_super_num_devices(&root->fs_info->super_copy,
1631                                     total_bytes + 1);
1632         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1633
1634         if (seeding_dev) {
1635                 ret = init_first_rw_device(trans, root, device);
1636                 BUG_ON(ret);
1637                 ret = btrfs_finish_sprout(trans, root);
1638                 BUG_ON(ret);
1639         } else {
1640                 ret = btrfs_add_device(trans, root, device);
1641         }
1642
1643         /*
1644          * we've got more storage, clear any full flags on the space
1645          * infos
1646          */
1647         btrfs_clear_space_info_full(root->fs_info);
1648
1649         unlock_chunks(root);
1650         btrfs_commit_transaction(trans, root);
1651
1652         if (seeding_dev) {
1653                 mutex_unlock(&uuid_mutex);
1654                 up_write(&sb->s_umount);
1655
1656                 ret = btrfs_relocate_sys_chunks(root);
1657                 BUG_ON(ret);
1658         }
1659 out:
1660         mutex_unlock(&root->fs_info->volume_mutex);
1661         return ret;
1662 error:
1663         blkdev_put(bdev, FMODE_EXCL);
1664         if (seeding_dev) {
1665                 mutex_unlock(&uuid_mutex);
1666                 up_write(&sb->s_umount);
1667         }
1668         goto out;
1669 }
1670
1671 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
1672                                         struct btrfs_device *device)
1673 {
1674         int ret;
1675         struct btrfs_path *path;
1676         struct btrfs_root *root;
1677         struct btrfs_dev_item *dev_item;
1678         struct extent_buffer *leaf;
1679         struct btrfs_key key;
1680
1681         root = device->dev_root->fs_info->chunk_root;
1682
1683         path = btrfs_alloc_path();
1684         if (!path)
1685                 return -ENOMEM;
1686
1687         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1688         key.type = BTRFS_DEV_ITEM_KEY;
1689         key.offset = device->devid;
1690
1691         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1692         if (ret < 0)
1693                 goto out;
1694
1695         if (ret > 0) {
1696                 ret = -ENOENT;
1697                 goto out;
1698         }
1699
1700         leaf = path->nodes[0];
1701         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1702
1703         btrfs_set_device_id(leaf, dev_item, device->devid);
1704         btrfs_set_device_type(leaf, dev_item, device->type);
1705         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1706         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1707         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1708         btrfs_set_device_total_bytes(leaf, dev_item, device->disk_total_bytes);
1709         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1710         btrfs_mark_buffer_dirty(leaf);
1711
1712 out:
1713         btrfs_free_path(path);
1714         return ret;
1715 }
1716
1717 static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
1718                       struct btrfs_device *device, u64 new_size)
1719 {
1720         struct btrfs_super_block *super_copy =
1721                 &device->dev_root->fs_info->super_copy;
1722         u64 old_total = btrfs_super_total_bytes(super_copy);
1723         u64 diff = new_size - device->total_bytes;
1724
1725         if (!device->writeable)
1726                 return -EACCES;
1727         if (new_size <= device->total_bytes)
1728                 return -EINVAL;
1729
1730         btrfs_set_super_total_bytes(super_copy, old_total + diff);
1731         device->fs_devices->total_rw_bytes += diff;
1732
1733         device->total_bytes = new_size;
1734         device->disk_total_bytes = new_size;
1735         btrfs_clear_space_info_full(device->dev_root->fs_info);
1736
1737         return btrfs_update_device(trans, device);
1738 }
1739
1740 int btrfs_grow_device(struct btrfs_trans_handle *trans,
1741                       struct btrfs_device *device, u64 new_size)
1742 {
1743         int ret;
1744         lock_chunks(device->dev_root);
1745         ret = __btrfs_grow_device(trans, device, new_size);
1746         unlock_chunks(device->dev_root);
1747         return ret;
1748 }
1749
1750 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
1751                             struct btrfs_root *root,
1752                             u64 chunk_tree, u64 chunk_objectid,
1753                             u64 chunk_offset)
1754 {
1755         int ret;
1756         struct btrfs_path *path;
1757         struct btrfs_key key;
1758
1759         root = root->fs_info->chunk_root;
1760         path = btrfs_alloc_path();
1761         if (!path)
1762                 return -ENOMEM;
1763
1764         key.objectid = chunk_objectid;
1765         key.offset = chunk_offset;
1766         key.type = BTRFS_CHUNK_ITEM_KEY;
1767
1768         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1769         BUG_ON(ret);
1770
1771         ret = btrfs_del_item(trans, root, path);
1772         BUG_ON(ret);
1773
1774         btrfs_free_path(path);
1775         return 0;
1776 }
1777
1778 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
1779                         chunk_offset)
1780 {
1781         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
1782         struct btrfs_disk_key *disk_key;
1783         struct btrfs_chunk *chunk;
1784         u8 *ptr;
1785         int ret = 0;
1786         u32 num_stripes;
1787         u32 array_size;
1788         u32 len = 0;
1789         u32 cur;
1790         struct btrfs_key key;
1791
1792         array_size = btrfs_super_sys_array_size(super_copy);
1793
1794         ptr = super_copy->sys_chunk_array;
1795         cur = 0;
1796
1797         while (cur < array_size) {
1798                 disk_key = (struct btrfs_disk_key *)ptr;
1799                 btrfs_disk_key_to_cpu(&key, disk_key);
1800
1801                 len = sizeof(*disk_key);
1802
1803                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
1804                         chunk = (struct btrfs_chunk *)(ptr + len);
1805                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
1806                         len += btrfs_chunk_item_size(num_stripes);
1807                 } else {
1808                         ret = -EIO;
1809                         break;
1810                 }
1811                 if (key.objectid == chunk_objectid &&
1812                     key.offset == chunk_offset) {
1813                         memmove(ptr, ptr + len, array_size - (cur + len));
1814                         array_size -= len;
1815                         btrfs_set_super_sys_array_size(super_copy, array_size);
1816                 } else {
1817                         ptr += len;
1818                         cur += len;
1819                 }
1820         }
1821         return ret;
1822 }
1823
1824 static int btrfs_relocate_chunk(struct btrfs_root *root,
1825                          u64 chunk_tree, u64 chunk_objectid,
1826                          u64 chunk_offset)
1827 {
1828         struct extent_map_tree *em_tree;
1829         struct btrfs_root *extent_root;
1830         struct btrfs_trans_handle *trans;
1831         struct extent_map *em;
1832         struct map_lookup *map;
1833         int ret;
1834         int i;
1835
1836         root = root->fs_info->chunk_root;
1837         extent_root = root->fs_info->extent_root;
1838         em_tree = &root->fs_info->mapping_tree.map_tree;
1839
1840         ret = btrfs_can_relocate(extent_root, chunk_offset);
1841         if (ret)
1842                 return -ENOSPC;
1843
1844         /* step one, relocate all the extents inside this chunk */
1845         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
1846         if (ret)
1847                 return ret;
1848
1849         trans = btrfs_start_transaction(root, 0);
1850         BUG_ON(IS_ERR(trans));
1851
1852         lock_chunks(root);
1853
1854         /*
1855          * step two, delete the device extents and the
1856          * chunk tree entries
1857          */
1858         read_lock(&em_tree->lock);
1859         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
1860         read_unlock(&em_tree->lock);
1861
1862         BUG_ON(em->start > chunk_offset ||
1863                em->start + em->len < chunk_offset);
1864         map = (struct map_lookup *)em->bdev;
1865
1866         for (i = 0; i < map->num_stripes; i++) {
1867                 ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
1868                                             map->stripes[i].physical);
1869                 BUG_ON(ret);
1870
1871                 if (map->stripes[i].dev) {
1872                         ret = btrfs_update_device(trans, map->stripes[i].dev);
1873                         BUG_ON(ret);
1874                 }
1875         }
1876         ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
1877                                chunk_offset);
1878
1879         BUG_ON(ret);
1880
1881         trace_btrfs_chunk_free(root, map, chunk_offset, em->len);
1882
1883         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
1884                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
1885                 BUG_ON(ret);
1886         }
1887
1888         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
1889         BUG_ON(ret);
1890
1891         write_lock(&em_tree->lock);
1892         remove_extent_mapping(em_tree, em);
1893         write_unlock(&em_tree->lock);
1894
1895         kfree(map);
1896         em->bdev = NULL;
1897
1898         /* once for the tree */
1899         free_extent_map(em);
1900         /* once for us */
1901         free_extent_map(em);
1902
1903         unlock_chunks(root);
1904         btrfs_end_transaction(trans, root);
1905         return 0;
1906 }
1907
1908 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
1909 {
1910         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
1911         struct btrfs_path *path;
1912         struct extent_buffer *leaf;
1913         struct btrfs_chunk *chunk;
1914         struct btrfs_key key;
1915         struct btrfs_key found_key;
1916         u64 chunk_tree = chunk_root->root_key.objectid;
1917         u64 chunk_type;
1918         bool retried = false;
1919         int failed = 0;
1920         int ret;
1921
1922         path = btrfs_alloc_path();
1923         if (!path)
1924                 return -ENOMEM;
1925
1926 again:
1927         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
1928         key.offset = (u64)-1;
1929         key.type = BTRFS_CHUNK_ITEM_KEY;
1930
1931         while (1) {
1932                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
1933                 if (ret < 0)
1934                         goto error;
1935                 BUG_ON(ret == 0);
1936
1937                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
1938                                           key.type);
1939                 if (ret < 0)
1940                         goto error;
1941                 if (ret > 0)
1942                         break;
1943
1944                 leaf = path->nodes[0];
1945                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1946
1947                 chunk = btrfs_item_ptr(leaf, path->slots[0],
1948                                        struct btrfs_chunk);
1949                 chunk_type = btrfs_chunk_type(leaf, chunk);
1950                 btrfs_release_path(path);
1951
1952                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
1953                         ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
1954                                                    found_key.objectid,
1955                                                    found_key.offset);
1956                         if (ret == -ENOSPC)
1957                                 failed++;
1958                         else if (ret)
1959                                 BUG();
1960                 }
1961
1962                 if (found_key.offset == 0)
1963                         break;
1964                 key.offset = found_key.offset - 1;
1965         }
1966         ret = 0;
1967         if (failed && !retried) {
1968                 failed = 0;
1969                 retried = true;
1970                 goto again;
1971         } else if (failed && retried) {
1972                 WARN_ON(1);
1973                 ret = -ENOSPC;
1974         }
1975 error:
1976         btrfs_free_path(path);
1977         return ret;
1978 }
1979
1980 static u64 div_factor(u64 num, int factor)
1981 {
1982         if (factor == 10)
1983                 return num;
1984         num *= factor;
1985         do_div(num, 10);
1986         return num;
1987 }
1988
1989 int btrfs_balance(struct btrfs_root *dev_root)
1990 {
1991         int ret;
1992         struct list_head *devices = &dev_root->fs_info->fs_devices->devices;
1993         struct btrfs_device *device;
1994         u64 old_size;
1995         u64 size_to_free;
1996         struct btrfs_path *path;
1997         struct btrfs_key key;
1998         struct btrfs_root *chunk_root = dev_root->fs_info->chunk_root;
1999         struct btrfs_trans_handle *trans;
2000         struct btrfs_key found_key;
2001
2002         if (dev_root->fs_info->sb->s_flags & MS_RDONLY)
2003                 return -EROFS;
2004
2005         if (!capable(CAP_SYS_ADMIN))
2006                 return -EPERM;
2007
2008         mutex_lock(&dev_root->fs_info->volume_mutex);
2009         dev_root = dev_root->fs_info->dev_root;
2010
2011         /* step one make some room on all the devices */
2012         list_for_each_entry(device, devices, dev_list) {
2013                 old_size = device->total_bytes;
2014                 size_to_free = div_factor(old_size, 1);
2015                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
2016                 if (!device->writeable ||
2017                     device->total_bytes - device->bytes_used > size_to_free)
2018                         continue;
2019
2020                 ret = btrfs_shrink_device(device, old_size - size_to_free);
2021                 if (ret == -ENOSPC)
2022                         break;
2023                 BUG_ON(ret);
2024
2025                 trans = btrfs_start_transaction(dev_root, 0);
2026                 BUG_ON(IS_ERR(trans));
2027
2028                 ret = btrfs_grow_device(trans, device, old_size);
2029                 BUG_ON(ret);
2030
2031                 btrfs_end_transaction(trans, dev_root);
2032         }
2033
2034         /* step two, relocate all the chunks */
2035         path = btrfs_alloc_path();
2036         BUG_ON(!path);
2037
2038         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2039         key.offset = (u64)-1;
2040         key.type = BTRFS_CHUNK_ITEM_KEY;
2041
2042         while (1) {
2043                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2044                 if (ret < 0)
2045                         goto error;
2046
2047                 /*
2048                  * this shouldn't happen, it means the last relocate
2049                  * failed
2050                  */
2051                 if (ret == 0)
2052                         break;
2053
2054                 ret = btrfs_previous_item(chunk_root, path, 0,
2055                                           BTRFS_CHUNK_ITEM_KEY);
2056                 if (ret)
2057                         break;
2058
2059                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
2060                                       path->slots[0]);
2061                 if (found_key.objectid != key.objectid)
2062                         break;
2063
2064                 /* chunk zero is special */
2065                 if (found_key.offset == 0)
2066                         break;
2067
2068                 btrfs_release_path(path);
2069                 ret = btrfs_relocate_chunk(chunk_root,
2070                                            chunk_root->root_key.objectid,
2071                                            found_key.objectid,
2072                                            found_key.offset);
2073                 BUG_ON(ret && ret != -ENOSPC);
2074                 key.offset = found_key.offset - 1;
2075         }
2076         ret = 0;
2077 error:
2078         btrfs_free_path(path);
2079         mutex_unlock(&dev_root->fs_info->volume_mutex);
2080         return ret;
2081 }
2082
2083 /*
2084  * shrinking a device means finding all of the device extents past
2085  * the new size, and then following the back refs to the chunks.
2086  * The chunk relocation code actually frees the device extent
2087  */
2088 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
2089 {
2090         struct btrfs_trans_handle *trans;
2091         struct btrfs_root *root = device->dev_root;
2092         struct btrfs_dev_extent *dev_extent = NULL;
2093         struct btrfs_path *path;
2094         u64 length;
2095         u64 chunk_tree;
2096         u64 chunk_objectid;
2097         u64 chunk_offset;
2098         int ret;
2099         int slot;
2100         int failed = 0;
2101         bool retried = false;
2102         struct extent_buffer *l;
2103         struct btrfs_key key;
2104         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
2105         u64 old_total = btrfs_super_total_bytes(super_copy);
2106         u64 old_size = device->total_bytes;
2107         u64 diff = device->total_bytes - new_size;
2108
2109         if (new_size >= device->total_bytes)
2110                 return -EINVAL;
2111
2112         path = btrfs_alloc_path();
2113         if (!path)
2114                 return -ENOMEM;
2115
2116         path->reada = 2;
2117
2118         lock_chunks(root);
2119
2120         device->total_bytes = new_size;
2121         if (device->writeable)
2122                 device->fs_devices->total_rw_bytes -= diff;
2123         unlock_chunks(root);
2124
2125 again:
2126         key.objectid = device->devid;
2127         key.offset = (u64)-1;
2128         key.type = BTRFS_DEV_EXTENT_KEY;
2129
2130         while (1) {
2131                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2132                 if (ret < 0)
2133                         goto done;
2134
2135                 ret = btrfs_previous_item(root, path, 0, key.type);
2136                 if (ret < 0)
2137                         goto done;
2138                 if (ret) {
2139                         ret = 0;
2140                         btrfs_release_path(path);
2141                         break;
2142                 }
2143
2144                 l = path->nodes[0];
2145                 slot = path->slots[0];
2146                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
2147
2148                 if (key.objectid != device->devid) {
2149                         btrfs_release_path(path);
2150                         break;
2151                 }
2152
2153                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
2154                 length = btrfs_dev_extent_length(l, dev_extent);
2155
2156                 if (key.offset + length <= new_size) {
2157                         btrfs_release_path(path);
2158                         break;
2159                 }
2160
2161                 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
2162                 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
2163                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
2164                 btrfs_release_path(path);
2165
2166                 ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
2167                                            chunk_offset);
2168                 if (ret && ret != -ENOSPC)
2169                         goto done;
2170                 if (ret == -ENOSPC)
2171                         failed++;
2172                 key.offset -= 1;
2173         }
2174
2175         if (failed && !retried) {
2176                 failed = 0;
2177                 retried = true;
2178                 goto again;
2179         } else if (failed && retried) {
2180                 ret = -ENOSPC;
2181                 lock_chunks(root);
2182
2183                 device->total_bytes = old_size;
2184                 if (device->writeable)
2185                         device->fs_devices->total_rw_bytes += diff;
2186                 unlock_chunks(root);
2187                 goto done;
2188         }
2189
2190         /* Shrinking succeeded, else we would be at "done". */
2191         trans = btrfs_start_transaction(root, 0);
2192         if (IS_ERR(trans)) {
2193                 ret = PTR_ERR(trans);
2194                 goto done;
2195         }
2196
2197         lock_chunks(root);
2198
2199         device->disk_total_bytes = new_size;
2200         /* Now btrfs_update_device() will change the on-disk size. */
2201         ret = btrfs_update_device(trans, device);
2202         if (ret) {
2203                 unlock_chunks(root);
2204                 btrfs_end_transaction(trans, root);
2205                 goto done;
2206         }
2207         WARN_ON(diff > old_total);
2208         btrfs_set_super_total_bytes(super_copy, old_total - diff);
2209         unlock_chunks(root);
2210         btrfs_end_transaction(trans, root);
2211 done:
2212         btrfs_free_path(path);
2213         return ret;
2214 }
2215
2216 static int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
2217                            struct btrfs_root *root,
2218                            struct btrfs_key *key,
2219                            struct btrfs_chunk *chunk, int item_size)
2220 {
2221         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
2222         struct btrfs_disk_key disk_key;
2223         u32 array_size;
2224         u8 *ptr;
2225
2226         array_size = btrfs_super_sys_array_size(super_copy);
2227         if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
2228                 return -EFBIG;
2229
2230         ptr = super_copy->sys_chunk_array + array_size;
2231         btrfs_cpu_key_to_disk(&disk_key, key);
2232         memcpy(ptr, &disk_key, sizeof(disk_key));
2233         ptr += sizeof(disk_key);
2234         memcpy(ptr, chunk, item_size);
2235         item_size += sizeof(disk_key);
2236         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
2237         return 0;
2238 }
2239
2240 static noinline u64 chunk_bytes_by_type(u64 type, u64 calc_size,
2241                                         int num_stripes, int sub_stripes)
2242 {
2243         if (type & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_DUP))
2244                 return calc_size;
2245         else if (type & BTRFS_BLOCK_GROUP_RAID10)
2246                 return calc_size * (num_stripes / sub_stripes);
2247         else
2248                 return calc_size * num_stripes;
2249 }
2250
2251 /* Used to sort the devices by max_avail(descending sort) */
2252 int btrfs_cmp_device_free_bytes(const void *dev_info1, const void *dev_info2)
2253 {
2254         if (((struct btrfs_device_info *)dev_info1)->max_avail >
2255             ((struct btrfs_device_info *)dev_info2)->max_avail)
2256                 return -1;
2257         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
2258                  ((struct btrfs_device_info *)dev_info2)->max_avail)
2259                 return 1;
2260         else
2261                 return 0;
2262 }
2263
2264 static int __btrfs_calc_nstripes(struct btrfs_fs_devices *fs_devices, u64 type,
2265                                  int *num_stripes, int *min_stripes,
2266                                  int *sub_stripes)
2267 {
2268         *num_stripes = 1;
2269         *min_stripes = 1;
2270         *sub_stripes = 0;
2271
2272         if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
2273                 *num_stripes = fs_devices->rw_devices;
2274                 *min_stripes = 2;
2275         }
2276         if (type & (BTRFS_BLOCK_GROUP_DUP)) {
2277                 *num_stripes = 2;
2278                 *min_stripes = 2;
2279         }
2280         if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
2281                 if (fs_devices->rw_devices < 2)
2282                         return -ENOSPC;
2283                 *num_stripes = 2;
2284                 *min_stripes = 2;
2285         }
2286         if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
2287                 *num_stripes = fs_devices->rw_devices;
2288                 if (*num_stripes < 4)
2289                         return -ENOSPC;
2290                 *num_stripes &= ~(u32)1;
2291                 *sub_stripes = 2;
2292                 *min_stripes = 4;
2293         }
2294
2295         return 0;
2296 }
2297
2298 static u64 __btrfs_calc_stripe_size(struct btrfs_fs_devices *fs_devices,
2299                                     u64 proposed_size, u64 type,
2300                                     int num_stripes, int small_stripe)
2301 {
2302         int min_stripe_size = 1 * 1024 * 1024;
2303         u64 calc_size = proposed_size;
2304         u64 max_chunk_size = calc_size;
2305         int ncopies = 1;
2306
2307         if (type & (BTRFS_BLOCK_GROUP_RAID1 |
2308                     BTRFS_BLOCK_GROUP_DUP |
2309                     BTRFS_BLOCK_GROUP_RAID10))
2310                 ncopies = 2;
2311
2312         if (type & BTRFS_BLOCK_GROUP_DATA) {
2313                 max_chunk_size = 10 * calc_size;
2314                 min_stripe_size = 64 * 1024 * 1024;
2315         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
2316                 max_chunk_size = 256 * 1024 * 1024;
2317                 min_stripe_size = 32 * 1024 * 1024;
2318         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
2319                 calc_size = 8 * 1024 * 1024;
2320                 max_chunk_size = calc_size * 2;
2321                 min_stripe_size = 1 * 1024 * 1024;
2322         }
2323
2324         /* we don't want a chunk larger than 10% of writeable space */
2325         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
2326                              max_chunk_size);
2327
2328         if (calc_size * num_stripes > max_chunk_size * ncopies) {
2329                 calc_size = max_chunk_size * ncopies;
2330                 do_div(calc_size, num_stripes);
2331                 do_div(calc_size, BTRFS_STRIPE_LEN);
2332                 calc_size *= BTRFS_STRIPE_LEN;
2333         }
2334
2335         /* we don't want tiny stripes */
2336         if (!small_stripe)
2337                 calc_size = max_t(u64, min_stripe_size, calc_size);
2338
2339         /*
2340          * we're about to do_div by the BTRFS_STRIPE_LEN so lets make sure
2341          * we end up with something bigger than a stripe
2342          */
2343         calc_size = max_t(u64, calc_size, BTRFS_STRIPE_LEN);
2344
2345         do_div(calc_size, BTRFS_STRIPE_LEN);
2346         calc_size *= BTRFS_STRIPE_LEN;
2347
2348         return calc_size;
2349 }
2350
2351 static struct map_lookup *__shrink_map_lookup_stripes(struct map_lookup *map,
2352                                                       int num_stripes)
2353 {
2354         struct map_lookup *new;
2355         size_t len = map_lookup_size(num_stripes);
2356
2357         BUG_ON(map->num_stripes < num_stripes);
2358
2359         if (map->num_stripes == num_stripes)
2360                 return map;
2361
2362         new = kmalloc(len, GFP_NOFS);
2363         if (!new) {
2364                 /* just change map->num_stripes */
2365                 map->num_stripes = num_stripes;
2366                 return map;
2367         }
2368
2369         memcpy(new, map, len);
2370         new->num_stripes = num_stripes;
2371         kfree(map);
2372         return new;
2373 }
2374
2375 /*
2376  * helper to allocate device space from btrfs_device_info, in which we stored
2377  * max free space information of every device. It is used when we can not
2378  * allocate chunks by default size.
2379  *
2380  * By this helper, we can allocate a new chunk as larger as possible.
2381  */
2382 static int __btrfs_alloc_tiny_space(struct btrfs_trans_handle *trans,
2383                                     struct btrfs_fs_devices *fs_devices,
2384                                     struct btrfs_device_info *devices,
2385                                     int nr_device, u64 type,
2386                                     struct map_lookup **map_lookup,
2387                                     int min_stripes, u64 *stripe_size)
2388 {
2389         int i, index, sort_again = 0;
2390         int min_devices = min_stripes;
2391         u64 max_avail, min_free;
2392         struct map_lookup *map = *map_lookup;
2393         int ret;
2394
2395         if (nr_device < min_stripes)
2396                 return -ENOSPC;
2397
2398         btrfs_descending_sort_devices(devices, nr_device);
2399
2400         max_avail = devices[0].max_avail;
2401         if (!max_avail)
2402                 return -ENOSPC;
2403
2404         for (i = 0; i < nr_device; i++) {
2405                 /*
2406                  * if dev_offset = 0, it means the free space of this device
2407                  * is less than what we need, and we didn't search max avail
2408                  * extent on this device, so do it now.
2409                  */
2410                 if (!devices[i].dev_offset) {
2411                         ret = find_free_dev_extent(trans, devices[i].dev,
2412                                                    max_avail,
2413                                                    &devices[i].dev_offset,
2414                                                    &devices[i].max_avail);
2415                         if (ret != 0 && ret != -ENOSPC)
2416                                 return ret;
2417                         sort_again = 1;
2418                 }
2419         }
2420
2421         /* we update the max avail free extent of each devices, sort again */
2422         if (sort_again)
2423                 btrfs_descending_sort_devices(devices, nr_device);
2424
2425         if (type & BTRFS_BLOCK_GROUP_DUP)
2426                 min_devices = 1;
2427
2428         if (!devices[min_devices - 1].max_avail)
2429                 return -ENOSPC;
2430
2431         max_avail = devices[min_devices - 1].max_avail;
2432         if (type & BTRFS_BLOCK_GROUP_DUP)
2433                 do_div(max_avail, 2);
2434
2435         max_avail = __btrfs_calc_stripe_size(fs_devices, max_avail, type,
2436                                              min_stripes, 1);
2437         if (type & BTRFS_BLOCK_GROUP_DUP)
2438                 min_free = max_avail * 2;
2439         else
2440                 min_free = max_avail;
2441
2442         if (min_free > devices[min_devices - 1].max_avail)
2443                 return -ENOSPC;
2444
2445         map = __shrink_map_lookup_stripes(map, min_stripes);
2446         *stripe_size = max_avail;
2447
2448         index = 0;
2449         for (i = 0; i < min_stripes; i++) {
2450                 map->stripes[i].dev = devices[index].dev;
2451                 map->stripes[i].physical = devices[index].dev_offset;
2452                 if (type & BTRFS_BLOCK_GROUP_DUP) {
2453                         i++;
2454                         map->stripes[i].dev = devices[index].dev;
2455                         map->stripes[i].physical = devices[index].dev_offset +
2456                                                    max_avail;
2457                 }
2458                 index++;
2459         }
2460         *map_lookup = map;
2461
2462         return 0;
2463 }
2464
2465 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
2466                                struct btrfs_root *extent_root,
2467                                struct map_lookup **map_ret,
2468                                u64 *num_bytes, u64 *stripe_size,
2469                                u64 start, u64 type)
2470 {
2471         struct btrfs_fs_info *info = extent_root->fs_info;
2472         struct btrfs_device *device = NULL;
2473         struct btrfs_fs_devices *fs_devices = info->fs_devices;
2474         struct list_head *cur;
2475         struct map_lookup *map;
2476         struct extent_map_tree *em_tree;
2477         struct extent_map *em;
2478         struct btrfs_device_info *devices_info;
2479         struct list_head private_devs;
2480         u64 calc_size = 1024 * 1024 * 1024;
2481         u64 min_free;
2482         u64 avail;
2483         u64 dev_offset;
2484         int num_stripes;
2485         int min_stripes;
2486         int sub_stripes;
2487         int min_devices;        /* the min number of devices we need */
2488         int i;
2489         int ret;
2490         int index;
2491
2492         if ((type & BTRFS_BLOCK_GROUP_RAID1) &&
2493             (type & BTRFS_BLOCK_GROUP_DUP)) {
2494                 WARN_ON(1);
2495                 type &= ~BTRFS_BLOCK_GROUP_DUP;
2496         }
2497         if (list_empty(&fs_devices->alloc_list))
2498                 return -ENOSPC;
2499
2500         ret = __btrfs_calc_nstripes(fs_devices, type, &num_stripes,
2501                                     &min_stripes, &sub_stripes);
2502         if (ret)
2503                 return ret;
2504
2505         devices_info = kzalloc(sizeof(*devices_info) * fs_devices->rw_devices,
2506                                GFP_NOFS);
2507         if (!devices_info)
2508                 return -ENOMEM;
2509
2510         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
2511         if (!map) {
2512                 ret = -ENOMEM;
2513                 goto error;
2514         }
2515         map->num_stripes = num_stripes;
2516
2517         cur = fs_devices->alloc_list.next;
2518         index = 0;
2519         i = 0;
2520
2521         calc_size = __btrfs_calc_stripe_size(fs_devices, calc_size, type,
2522                                              num_stripes, 0);
2523
2524         if (type & BTRFS_BLOCK_GROUP_DUP) {
2525                 min_free = calc_size * 2;
2526                 min_devices = 1;
2527         } else {
2528                 min_free = calc_size;
2529                 min_devices = min_stripes;
2530         }
2531
2532         INIT_LIST_HEAD(&private_devs);
2533         while (index < num_stripes) {
2534                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
2535                 BUG_ON(!device->writeable);
2536                 if (device->total_bytes > device->bytes_used)
2537                         avail = device->total_bytes - device->bytes_used;
2538                 else
2539                         avail = 0;
2540                 cur = cur->next;
2541
2542                 if (device->in_fs_metadata && avail >= min_free) {
2543                         ret = find_free_dev_extent(trans, device, min_free,
2544                                                    &devices_info[i].dev_offset,
2545                                                    &devices_info[i].max_avail);
2546                         if (ret == 0) {
2547                                 list_move_tail(&device->dev_alloc_list,
2548                                                &private_devs);
2549                                 map->stripes[index].dev = device;
2550                                 map->stripes[index].physical =
2551                                                 devices_info[i].dev_offset;
2552                                 index++;
2553                                 if (type & BTRFS_BLOCK_GROUP_DUP) {
2554                                         map->stripes[index].dev = device;
2555                                         map->stripes[index].physical =
2556                                                 devices_info[i].dev_offset +
2557                                                 calc_size;
2558                                         index++;
2559                                 }
2560                         } else if (ret != -ENOSPC)
2561                                 goto error;
2562
2563                         devices_info[i].dev = device;
2564                         i++;
2565                 } else if (device->in_fs_metadata &&
2566                            avail >= BTRFS_STRIPE_LEN) {
2567                         devices_info[i].dev = device;
2568                         devices_info[i].max_avail = avail;
2569                         i++;
2570                 }
2571
2572                 if (cur == &fs_devices->alloc_list)
2573                         break;
2574         }
2575
2576         list_splice(&private_devs, &fs_devices->alloc_list);
2577         if (index < num_stripes) {
2578                 if (index >= min_stripes) {
2579                         num_stripes = index;
2580                         if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
2581                                 num_stripes /= sub_stripes;
2582                                 num_stripes *= sub_stripes;
2583                         }
2584
2585                         map = __shrink_map_lookup_stripes(map, num_stripes);
2586                 } else if (i >= min_devices) {
2587                         ret = __btrfs_alloc_tiny_space(trans, fs_devices,
2588                                                        devices_info, i, type,
2589                                                        &map, min_stripes,
2590                                                        &calc_size);
2591                         if (ret)
2592                                 goto error;
2593                 } else {
2594                         ret = -ENOSPC;
2595                         goto error;
2596                 }
2597         }
2598         map->sector_size = extent_root->sectorsize;
2599         map->stripe_len = BTRFS_STRIPE_LEN;
2600         map->io_align = BTRFS_STRIPE_LEN;
2601         map->io_width = BTRFS_STRIPE_LEN;
2602         map->type = type;
2603         map->sub_stripes = sub_stripes;
2604
2605         *map_ret = map;
2606         *stripe_size = calc_size;
2607         *num_bytes = chunk_bytes_by_type(type, calc_size,
2608                                          map->num_stripes, sub_stripes);
2609
2610         trace_btrfs_chunk_alloc(info->chunk_root, map, start, *num_bytes);
2611
2612         em = alloc_extent_map();
2613         if (!em) {
2614                 ret = -ENOMEM;
2615                 goto error;
2616         }
2617         em->bdev = (struct block_device *)map;
2618         em->start = start;
2619         em->len = *num_bytes;
2620         em->block_start = 0;
2621         em->block_len = em->len;
2622
2623         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
2624         write_lock(&em_tree->lock);
2625         ret = add_extent_mapping(em_tree, em);
2626         write_unlock(&em_tree->lock);
2627         BUG_ON(ret);
2628         free_extent_map(em);
2629
2630         ret = btrfs_make_block_group(trans, extent_root, 0, type,
2631                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2632                                      start, *num_bytes);
2633         BUG_ON(ret);
2634
2635         index = 0;
2636         while (index < map->num_stripes) {
2637                 device = map->stripes[index].dev;
2638                 dev_offset = map->stripes[index].physical;
2639
2640                 ret = btrfs_alloc_dev_extent(trans, device,
2641                                 info->chunk_root->root_key.objectid,
2642                                 BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2643                                 start, dev_offset, calc_size);
2644                 BUG_ON(ret);
2645                 index++;
2646         }
2647
2648         kfree(devices_info);
2649         return 0;
2650
2651 error:
2652         kfree(map);
2653         kfree(devices_info);
2654         return ret;
2655 }
2656
2657 static int __finish_chunk_alloc(struct btrfs_trans_handle *trans,
2658                                 struct btrfs_root *extent_root,
2659                                 struct map_lookup *map, u64 chunk_offset,
2660                                 u64 chunk_size, u64 stripe_size)
2661 {
2662         u64 dev_offset;
2663         struct btrfs_key key;
2664         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
2665         struct btrfs_device *device;
2666         struct btrfs_chunk *chunk;
2667         struct btrfs_stripe *stripe;
2668         size_t item_size = btrfs_chunk_item_size(map->num_stripes);
2669         int index = 0;
2670         int ret;
2671
2672         chunk = kzalloc(item_size, GFP_NOFS);
2673         if (!chunk)
2674                 return -ENOMEM;
2675
2676         index = 0;
2677         while (index < map->num_stripes) {
2678                 device = map->stripes[index].dev;
2679                 device->bytes_used += stripe_size;
2680                 ret = btrfs_update_device(trans, device);
2681                 BUG_ON(ret);
2682                 index++;
2683         }
2684
2685         index = 0;
2686         stripe = &chunk->stripe;
2687         while (index < map->num_stripes) {
2688                 device = map->stripes[index].dev;
2689                 dev_offset = map->stripes[index].physical;
2690
2691                 btrfs_set_stack_stripe_devid(stripe, device->devid);
2692                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
2693                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
2694                 stripe++;
2695                 index++;
2696         }
2697
2698         btrfs_set_stack_chunk_length(chunk, chunk_size);
2699         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
2700         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
2701         btrfs_set_stack_chunk_type(chunk, map->type);
2702         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
2703         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
2704         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
2705         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
2706         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
2707
2708         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2709         key.type = BTRFS_CHUNK_ITEM_KEY;
2710         key.offset = chunk_offset;
2711
2712         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
2713         BUG_ON(ret);
2714
2715         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2716                 ret = btrfs_add_system_chunk(trans, chunk_root, &key, chunk,
2717                                              item_size);
2718                 BUG_ON(ret);
2719         }
2720
2721         kfree(chunk);
2722         return 0;
2723 }
2724
2725 /*
2726  * Chunk allocation falls into two parts. The first part does works
2727  * that make the new allocated chunk useable, but not do any operation
2728  * that modifies the chunk tree. The second part does the works that
2729  * require modifying the chunk tree. This division is important for the
2730  * bootstrap process of adding storage to a seed btrfs.
2731  */
2732 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
2733                       struct btrfs_root *extent_root, u64 type)
2734 {
2735         u64 chunk_offset;
2736         u64 chunk_size;
2737         u64 stripe_size;
2738         struct map_lookup *map;
2739         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
2740         int ret;
2741
2742         ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
2743                               &chunk_offset);
2744         if (ret)
2745                 return ret;
2746
2747         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
2748                                   &stripe_size, chunk_offset, type);
2749         if (ret)
2750                 return ret;
2751
2752         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
2753                                    chunk_size, stripe_size);
2754         BUG_ON(ret);
2755         return 0;
2756 }
2757
2758 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
2759                                          struct btrfs_root *root,
2760                                          struct btrfs_device *device)
2761 {
2762         u64 chunk_offset;
2763         u64 sys_chunk_offset;
2764         u64 chunk_size;
2765         u64 sys_chunk_size;
2766         u64 stripe_size;
2767         u64 sys_stripe_size;
2768         u64 alloc_profile;
2769         struct map_lookup *map;
2770         struct map_lookup *sys_map;
2771         struct btrfs_fs_info *fs_info = root->fs_info;
2772         struct btrfs_root *extent_root = fs_info->extent_root;
2773         int ret;
2774
2775         ret = find_next_chunk(fs_info->chunk_root,
2776                               BTRFS_FIRST_CHUNK_TREE_OBJECTID, &chunk_offset);
2777         BUG_ON(ret);
2778
2779         alloc_profile = BTRFS_BLOCK_GROUP_METADATA |
2780                         (fs_info->metadata_alloc_profile &
2781                          fs_info->avail_metadata_alloc_bits);
2782         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
2783
2784         ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
2785                                   &stripe_size, chunk_offset, alloc_profile);
2786         BUG_ON(ret);
2787
2788         sys_chunk_offset = chunk_offset + chunk_size;
2789
2790         alloc_profile = BTRFS_BLOCK_GROUP_SYSTEM |
2791                         (fs_info->system_alloc_profile &
2792                          fs_info->avail_system_alloc_bits);
2793         alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
2794
2795         ret = __btrfs_alloc_chunk(trans, extent_root, &sys_map,
2796                                   &sys_chunk_size, &sys_stripe_size,
2797                                   sys_chunk_offset, alloc_profile);
2798         BUG_ON(ret);
2799
2800         ret = btrfs_add_device(trans, fs_info->chunk_root, device);
2801         BUG_ON(ret);
2802
2803         /*
2804          * Modifying chunk tree needs allocating new blocks from both
2805          * system block group and metadata block group. So we only can
2806          * do operations require modifying the chunk tree after both
2807          * block groups were created.
2808          */
2809         ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
2810                                    chunk_size, stripe_size);
2811         BUG_ON(ret);
2812
2813         ret = __finish_chunk_alloc(trans, extent_root, sys_map,
2814                                    sys_chunk_offset, sys_chunk_size,
2815                                    sys_stripe_size);
2816         BUG_ON(ret);
2817         return 0;
2818 }
2819
2820 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
2821 {
2822         struct extent_map *em;
2823         struct map_lookup *map;
2824         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
2825         int readonly = 0;
2826         int i;
2827
2828         read_lock(&map_tree->map_tree.lock);
2829         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
2830         read_unlock(&map_tree->map_tree.lock);
2831         if (!em)
2832                 return 1;
2833
2834         if (btrfs_test_opt(root, DEGRADED)) {
2835                 free_extent_map(em);
2836                 return 0;
2837         }
2838
2839         map = (struct map_lookup *)em->bdev;
2840         for (i = 0; i < map->num_stripes; i++) {
2841                 if (!map->stripes[i].dev->writeable) {
2842                         readonly = 1;
2843                         break;
2844                 }
2845         }
2846         free_extent_map(em);
2847         return readonly;
2848 }
2849
2850 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
2851 {
2852         extent_map_tree_init(&tree->map_tree);
2853 }
2854
2855 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
2856 {
2857         struct extent_map *em;
2858
2859         while (1) {
2860                 write_lock(&tree->map_tree.lock);
2861                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
2862                 if (em)
2863                         remove_extent_mapping(&tree->map_tree, em);
2864                 write_unlock(&tree->map_tree.lock);
2865                 if (!em)
2866                         break;
2867                 kfree(em->bdev);
2868                 /* once for us */
2869                 free_extent_map(em);
2870                 /* once for the tree */
2871                 free_extent_map(em);
2872         }
2873 }
2874
2875 int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
2876 {
2877         struct extent_map *em;
2878         struct map_lookup *map;
2879         struct extent_map_tree *em_tree = &map_tree->map_tree;
2880         int ret;
2881
2882         read_lock(&em_tree->lock);
2883         em = lookup_extent_mapping(em_tree, logical, len);
2884         read_unlock(&em_tree->lock);
2885         BUG_ON(!em);
2886
2887         BUG_ON(em->start > logical || em->start + em->len < logical);
2888         map = (struct map_lookup *)em->bdev;
2889         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
2890                 ret = map->num_stripes;
2891         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
2892                 ret = map->sub_stripes;
2893         else
2894                 ret = 1;
2895         free_extent_map(em);
2896         return ret;
2897 }
2898
2899 static int find_live_mirror(struct map_lookup *map, int first, int num,
2900                             int optimal)
2901 {
2902         int i;
2903         if (map->stripes[optimal].dev->bdev)
2904                 return optimal;
2905         for (i = first; i < first + num; i++) {
2906                 if (map->stripes[i].dev->bdev)
2907                         return i;
2908         }
2909         /* we couldn't find one that doesn't fail.  Just return something
2910          * and the io error handling code will clean up eventually
2911          */
2912         return optimal;
2913 }
2914
2915 static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
2916                              u64 logical, u64 *length,
2917                              struct btrfs_multi_bio **multi_ret,
2918                              int mirror_num)
2919 {
2920         struct extent_map *em;
2921         struct map_lookup *map;
2922         struct extent_map_tree *em_tree = &map_tree->map_tree;
2923         u64 offset;
2924         u64 stripe_offset;
2925         u64 stripe_end_offset;
2926         u64 stripe_nr;
2927         u64 stripe_nr_orig;
2928         u64 stripe_nr_end;
2929         int stripes_allocated = 8;
2930         int stripes_required = 1;
2931         int stripe_index;
2932         int i;
2933         int num_stripes;
2934         int max_errors = 0;
2935         struct btrfs_multi_bio *multi = NULL;
2936
2937         if (multi_ret && !(rw & (REQ_WRITE | REQ_DISCARD)))
2938                 stripes_allocated = 1;
2939 again:
2940         if (multi_ret) {
2941                 multi = kzalloc(btrfs_multi_bio_size(stripes_allocated),
2942                                 GFP_NOFS);
2943                 if (!multi)
2944                         return -ENOMEM;
2945
2946                 atomic_set(&multi->error, 0);
2947         }
2948
2949         read_lock(&em_tree->lock);
2950         em = lookup_extent_mapping(em_tree, logical, *length);
2951         read_unlock(&em_tree->lock);
2952
2953         if (!em) {
2954                 printk(KERN_CRIT "unable to find logical %llu len %llu\n",
2955                        (unsigned long long)logical,
2956                        (unsigned long long)*length);
2957                 BUG();
2958         }
2959
2960         BUG_ON(em->start > logical || em->start + em->len < logical);
2961         map = (struct map_lookup *)em->bdev;
2962         offset = logical - em->start;
2963
2964         if (mirror_num > map->num_stripes)
2965                 mirror_num = 0;
2966
2967         /* if our multi bio struct is too small, back off and try again */
2968         if (rw & REQ_WRITE) {
2969                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
2970                                  BTRFS_BLOCK_GROUP_DUP)) {
2971                         stripes_required = map->num_stripes;
2972                         max_errors = 1;
2973                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
2974                         stripes_required = map->sub_stripes;
2975                         max_errors = 1;
2976                 }
2977         }
2978         if (rw & REQ_DISCARD) {
2979                 if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
2980                                  BTRFS_BLOCK_GROUP_RAID1 |
2981                                  BTRFS_BLOCK_GROUP_DUP |
2982                                  BTRFS_BLOCK_GROUP_RAID10)) {
2983                         stripes_required = map->num_stripes;
2984                 }
2985         }
2986         if (multi_ret && (rw & (REQ_WRITE | REQ_DISCARD)) &&
2987             stripes_allocated < stripes_required) {
2988                 stripes_allocated = map->num_stripes;
2989                 free_extent_map(em);
2990                 kfree(multi);
2991                 goto again;
2992         }
2993         stripe_nr = offset;
2994         /*
2995          * stripe_nr counts the total number of stripes we have to stride
2996          * to get to this block
2997          */
2998         do_div(stripe_nr, map->stripe_len);
2999
3000         stripe_offset = stripe_nr * map->stripe_len;
3001         BUG_ON(offset < stripe_offset);
3002
3003         /* stripe_offset is the offset of this block in its stripe*/
3004         stripe_offset = offset - stripe_offset;
3005
3006         if (rw & REQ_DISCARD)
3007                 *length = min_t(u64, em->len - offset, *length);
3008         else if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
3009                               BTRFS_BLOCK_GROUP_RAID1 |
3010                               BTRFS_BLOCK_GROUP_RAID10 |
3011                               BTRFS_BLOCK_GROUP_DUP)) {
3012                 /* we limit the length of each bio to what fits in a stripe */
3013                 *length = min_t(u64, em->len - offset,
3014                                 map->stripe_len - stripe_offset);
3015         } else {
3016                 *length = em->len - offset;
3017         }
3018
3019         if (!multi_ret)
3020                 goto out;
3021
3022         num_stripes = 1;
3023         stripe_index = 0;
3024         stripe_nr_orig = stripe_nr;
3025         stripe_nr_end = (offset + *length + map->stripe_len - 1) &
3026                         (~(map->stripe_len - 1));
3027         do_div(stripe_nr_end, map->stripe_len);
3028         stripe_end_offset = stripe_nr_end * map->stripe_len -
3029                             (offset + *length);
3030         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
3031                 if (rw & REQ_DISCARD)
3032                         num_stripes = min_t(u64, map->num_stripes,
3033                                             stripe_nr_end - stripe_nr_orig);
3034                 stripe_index = do_div(stripe_nr, map->num_stripes);
3035         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
3036                 if (rw & (REQ_WRITE | REQ_DISCARD))
3037                         num_stripes = map->num_stripes;
3038                 else if (mirror_num)
3039                         stripe_index = mirror_num - 1;
3040                 else {
3041                         stripe_index = find_live_mirror(map, 0,
3042                                             map->num_stripes,
3043                                             current->pid % map->num_stripes);
3044                 }
3045
3046         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
3047                 if (rw & (REQ_WRITE | REQ_DISCARD))
3048                         num_stripes = map->num_stripes;
3049                 else if (mirror_num)
3050                         stripe_index = mirror_num - 1;
3051
3052         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
3053                 int factor = map->num_stripes / map->sub_stripes;
3054
3055                 stripe_index = do_div(stripe_nr, factor);
3056                 stripe_index *= map->sub_stripes;
3057
3058                 if (rw & REQ_WRITE)
3059                         num_stripes = map->sub_stripes;
3060                 else if (rw & REQ_DISCARD)
3061                         num_stripes = min_t(u64, map->sub_stripes *
3062                                             (stripe_nr_end - stripe_nr_orig),
3063                                             map->num_stripes);
3064                 else if (mirror_num)
3065                         stripe_index += mirror_num - 1;
3066                 else {
3067                         stripe_index = find_live_mirror(map, stripe_index,
3068                                               map->sub_stripes, stripe_index +
3069                                               current->pid % map->sub_stripes);
3070                 }
3071         } else {
3072                 /*
3073                  * after this do_div call, stripe_nr is the number of stripes
3074                  * on this device we have to walk to find the data, and
3075                  * stripe_index is the number of our device in the stripe array
3076                  */
3077                 stripe_index = do_div(stripe_nr, map->num_stripes);
3078         }
3079         BUG_ON(stripe_index >= map->num_stripes);
3080
3081         if (rw & REQ_DISCARD) {
3082                 for (i = 0; i < num_stripes; i++) {
3083                         multi->stripes[i].physical =
3084                                 map->stripes[stripe_index].physical +
3085                                 stripe_offset + stripe_nr * map->stripe_len;
3086                         multi->stripes[i].dev = map->stripes[stripe_index].dev;
3087
3088                         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
3089                                 u64 stripes;
3090                                 u32 last_stripe = 0;
3091                                 int j;
3092
3093                                 div_u64_rem(stripe_nr_end - 1,
3094                                             map->num_stripes,
3095                                             &last_stripe);
3096
3097                                 for (j = 0; j < map->num_stripes; j++) {
3098                                         u32 test;
3099
3100                                         div_u64_rem(stripe_nr_end - 1 - j,
3101                                                     map->num_stripes, &test);
3102                                         if (test == stripe_index)
3103                                                 break;
3104                                 }
3105                                 stripes = stripe_nr_end - 1 - j;
3106                                 do_div(stripes, map->num_stripes);
3107                                 multi->stripes[i].length = map->stripe_len *
3108                                         (stripes - stripe_nr + 1);
3109
3110                                 if (i == 0) {
3111                                         multi->stripes[i].length -=
3112                                                 stripe_offset;
3113                                         stripe_offset = 0;
3114                                 }
3115                                 if (stripe_index == last_stripe)
3116                                         multi->stripes[i].length -=
3117                                                 stripe_end_offset;
3118                         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
3119                                 u64 stripes;
3120                                 int j;
3121                                 int factor = map->num_stripes /
3122                                              map->sub_stripes;
3123                                 u32 last_stripe = 0;
3124
3125                                 div_u64_rem(stripe_nr_end - 1,
3126                                             factor, &last_stripe);
3127                                 last_stripe *= map->sub_stripes;
3128
3129                                 for (j = 0; j < factor; j++) {
3130                                         u32 test;
3131
3132                                         div_u64_rem(stripe_nr_end - 1 - j,
3133                                                     factor, &test);
3134
3135                                         if (test ==
3136                                             stripe_index / map->sub_stripes)
3137                                                 break;
3138                                 }
3139                                 stripes = stripe_nr_end - 1 - j;
3140                                 do_div(stripes, factor);
3141                                 multi->stripes[i].length = map->stripe_len *
3142                                         (stripes - stripe_nr + 1);
3143
3144                                 if (i < map->sub_stripes) {
3145                                         multi->stripes[i].length -=
3146                                                 stripe_offset;
3147                                         if (i == map->sub_stripes - 1)
3148                                                 stripe_offset = 0;
3149                                 }
3150                                 if (stripe_index >= last_stripe &&
3151                                     stripe_index <= (last_stripe +
3152                                                      map->sub_stripes - 1)) {
3153                                         multi->stripes[i].length -=
3154                                                 stripe_end_offset;
3155                                 }
3156                         } else
3157                                 multi->stripes[i].length = *length;
3158
3159                         stripe_index++;
3160                         if (stripe_index == map->num_stripes) {
3161                                 /* This could only happen for RAID0/10 */
3162                                 stripe_index = 0;
3163                                 stripe_nr++;
3164                         }
3165                 }
3166         } else {
3167                 for (i = 0; i < num_stripes; i++) {
3168                         multi->stripes[i].physical =
3169                                 map->stripes[stripe_index].physical +
3170                                 stripe_offset +
3171                                 stripe_nr * map->stripe_len;
3172                         multi->stripes[i].dev =
3173                                 map->stripes[stripe_index].dev;
3174                         stripe_index++;
3175                 }
3176         }
3177         if (multi_ret) {
3178                 *multi_ret = multi;
3179                 multi->num_stripes = num_stripes;
3180                 multi->max_errors = max_errors;
3181         }
3182 out:
3183         free_extent_map(em);
3184         return 0;
3185 }
3186
3187 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
3188                       u64 logical, u64 *length,
3189                       struct btrfs_multi_bio **multi_ret, int mirror_num)
3190 {
3191         return __btrfs_map_block(map_tree, rw, logical, length, multi_ret,
3192                                  mirror_num);
3193 }
3194
3195 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
3196                      u64 chunk_start, u64 physical, u64 devid,
3197                      u64 **logical, int *naddrs, int *stripe_len)
3198 {
3199         struct extent_map_tree *em_tree = &map_tree->map_tree;
3200         struct extent_map *em;
3201         struct map_lookup *map;
3202         u64 *buf;
3203         u64 bytenr;
3204         u64 length;
3205         u64 stripe_nr;
3206         int i, j, nr = 0;
3207
3208         read_lock(&em_tree->lock);
3209         em = lookup_extent_mapping(em_tree, chunk_start, 1);
3210         read_unlock(&em_tree->lock);
3211
3212         BUG_ON(!em || em->start != chunk_start);
3213         map = (struct map_lookup *)em->bdev;
3214
3215         length = em->len;
3216         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
3217                 do_div(length, map->num_stripes / map->sub_stripes);
3218         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
3219                 do_div(length, map->num_stripes);
3220
3221         buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
3222         BUG_ON(!buf);
3223
3224         for (i = 0; i < map->num_stripes; i++) {
3225                 if (devid && map->stripes[i].dev->devid != devid)
3226                         continue;
3227                 if (map->stripes[i].physical > physical ||
3228                     map->stripes[i].physical + length <= physical)
3229                         continue;
3230
3231                 stripe_nr = physical - map->stripes[i].physical;
3232                 do_div(stripe_nr, map->stripe_len);
3233
3234                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
3235                         stripe_nr = stripe_nr * map->num_stripes + i;
3236                         do_div(stripe_nr, map->sub_stripes);
3237                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
3238                         stripe_nr = stripe_nr * map->num_stripes + i;
3239                 }
3240                 bytenr = chunk_start + stripe_nr * map->stripe_len;
3241                 WARN_ON(nr >= map->num_stripes);
3242                 for (j = 0; j < nr; j++) {
3243                         if (buf[j] == bytenr)
3244                                 break;
3245                 }
3246                 if (j == nr) {
3247                         WARN_ON(nr >= map->num_stripes);
3248                         buf[nr++] = bytenr;
3249                 }
3250         }
3251
3252         *logical = buf;
3253         *naddrs = nr;
3254         *stripe_len = map->stripe_len;
3255
3256         free_extent_map(em);
3257         return 0;
3258 }
3259
3260 static void end_bio_multi_stripe(struct bio *bio, int err)
3261 {
3262         struct btrfs_multi_bio *multi = bio->bi_private;
3263         int is_orig_bio = 0;
3264
3265         if (err)
3266                 atomic_inc(&multi->error);
3267
3268         if (bio == multi->orig_bio)
3269                 is_orig_bio = 1;
3270
3271         if (atomic_dec_and_test(&multi->stripes_pending)) {
3272                 if (!is_orig_bio) {
3273                         bio_put(bio);
3274                         bio = multi->orig_bio;
3275                 }
3276                 bio->bi_private = multi->private;
3277                 bio->bi_end_io = multi->end_io;
3278                 /* only send an error to the higher layers if it is
3279                  * beyond the tolerance of the multi-bio
3280                  */
3281                 if (atomic_read(&multi->error) > multi->max_errors) {
3282                         err = -EIO;
3283                 } else if (err) {
3284                         /*
3285                          * this bio is actually up to date, we didn't
3286                          * go over the max number of errors
3287                          */
3288                         set_bit(BIO_UPTODATE, &bio->bi_flags);
3289                         err = 0;
3290                 }
3291                 kfree(multi);
3292
3293                 bio_endio(bio, err);
3294         } else if (!is_orig_bio) {
3295                 bio_put(bio);
3296         }
3297 }
3298
3299 struct async_sched {
3300         struct bio *bio;
3301         int rw;
3302         struct btrfs_fs_info *info;
3303         struct btrfs_work work;
3304 };
3305
3306 /*
3307  * see run_scheduled_bios for a description of why bios are collected for
3308  * async submit.
3309  *
3310  * This will add one bio to the pending list for a device and make sure
3311  * the work struct is scheduled.
3312  */
3313 static noinline int schedule_bio(struct btrfs_root *root,
3314                                  struct btrfs_device *device,
3315                                  int rw, struct bio *bio)
3316 {
3317         int should_queue = 1;
3318         struct btrfs_pending_bios *pending_bios;
3319
3320         /* don't bother with additional async steps for reads, right now */
3321         if (!(rw & REQ_WRITE)) {
3322                 bio_get(bio);
3323                 submit_bio(rw, bio);
3324                 bio_put(bio);
3325                 return 0;
3326         }
3327
3328         /*
3329          * nr_async_bios allows us to reliably return congestion to the
3330          * higher layers.  Otherwise, the async bio makes it appear we have
3331          * made progress against dirty pages when we've really just put it
3332          * on a queue for later
3333          */
3334         atomic_inc(&root->fs_info->nr_async_bios);
3335         WARN_ON(bio->bi_next);
3336         bio->bi_next = NULL;
3337         bio->bi_rw |= rw;
3338
3339         spin_lock(&device->io_lock);
3340         if (bio->bi_rw & REQ_SYNC)
3341                 pending_bios = &device->pending_sync_bios;
3342         else
3343                 pending_bios = &device->pending_bios;
3344
3345         if (pending_bios->tail)
3346                 pending_bios->tail->bi_next = bio;
3347
3348         pending_bios->tail = bio;
3349         if (!pending_bios->head)
3350                 pending_bios->head = bio;
3351         if (device->running_pending)
3352                 should_queue = 0;
3353
3354         spin_unlock(&device->io_lock);
3355
3356         if (should_queue)
3357                 btrfs_queue_worker(&root->fs_info->submit_workers,
3358                                    &device->work);
3359         return 0;
3360 }
3361
3362 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
3363                   int mirror_num, int async_submit)
3364 {
3365         struct btrfs_mapping_tree *map_tree;
3366         struct btrfs_device *dev;
3367         struct bio *first_bio = bio;
3368         u64 logical = (u64)bio->bi_sector << 9;
3369         u64 length = 0;
3370         u64 map_length;
3371         struct btrfs_multi_bio *multi = NULL;
3372         int ret;
3373         int dev_nr = 0;
3374         int total_devs = 1;
3375
3376         length = bio->bi_size;
3377         map_tree = &root->fs_info->mapping_tree;
3378         map_length = length;
3379
3380         ret = btrfs_map_block(map_tree, rw, logical, &map_length, &multi,
3381                               mirror_num);
3382         BUG_ON(ret);
3383
3384         total_devs = multi->num_stripes;
3385         if (map_length < length) {
3386                 printk(KERN_CRIT "mapping failed logical %llu bio len %llu "
3387                        "len %llu\n", (unsigned long long)logical,
3388                        (unsigned long long)length,
3389                        (unsigned long long)map_length);
3390                 BUG();
3391         }
3392         multi->end_io = first_bio->bi_end_io;
3393         multi->private = first_bio->bi_private;
3394         multi->orig_bio = first_bio;
3395         atomic_set(&multi->stripes_pending, multi->num_stripes);
3396
3397         while (dev_nr < total_devs) {
3398                 if (total_devs > 1) {
3399                         if (dev_nr < total_devs - 1) {
3400                                 bio = bio_clone(first_bio, GFP_NOFS);
3401                                 BUG_ON(!bio);
3402                         } else {
3403                                 bio = first_bio;
3404                         }
3405                         bio->bi_private = multi;
3406                         bio->bi_end_io = end_bio_multi_stripe;
3407                 }
3408                 bio->bi_sector = multi->stripes[dev_nr].physical >> 9;
3409                 dev = multi->stripes[dev_nr].dev;
3410                 if (dev && dev->bdev && (rw != WRITE || dev->writeable)) {
3411                         bio->bi_bdev = dev->bdev;
3412                         if (async_submit)
3413                                 schedule_bio(root, dev, rw, bio);
3414                         else
3415                                 submit_bio(rw, bio);
3416                 } else {
3417                         bio->bi_bdev = root->fs_info->fs_devices->latest_bdev;
3418                         bio->bi_sector = logical >> 9;
3419                         bio_endio(bio, -EIO);
3420                 }
3421                 dev_nr++;
3422         }
3423         if (total_devs == 1)
3424                 kfree(multi);
3425         return 0;
3426 }
3427
3428 struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
3429                                        u8 *uuid, u8 *fsid)
3430 {
3431         struct btrfs_device *device;
3432         struct btrfs_fs_devices *cur_devices;
3433
3434         cur_devices = root->fs_info->fs_devices;
3435         while (cur_devices) {
3436                 if (!fsid ||
3437                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
3438                         device = __find_device(&cur_devices->devices,
3439                                                devid, uuid);
3440                         if (device)
3441                                 return device;
3442                 }
3443                 cur_devices = cur_devices->seed;
3444         }
3445         return NULL;
3446 }
3447
3448 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
3449                                             u64 devid, u8 *dev_uuid)
3450 {
3451         struct btrfs_device *device;
3452         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
3453
3454         device = kzalloc(sizeof(*device), GFP_NOFS);
3455         if (!device)
3456                 return NULL;
3457         list_add(&device->dev_list,
3458                  &fs_devices->devices);
3459         device->dev_root = root->fs_info->dev_root;
3460         device->devid = devid;
3461         device->work.func = pending_bios_fn;
3462         device->fs_devices = fs_devices;
3463         device->missing = 1;
3464         fs_devices->num_devices++;
3465         fs_devices->missing_devices++;
3466         spin_lock_init(&device->io_lock);
3467         INIT_LIST_HEAD(&device->dev_alloc_list);
3468         memcpy(device->uuid, dev_uuid, BTRFS_UUID_SIZE);
3469         return device;
3470 }
3471
3472 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
3473                           struct extent_buffer *leaf,
3474                           struct btrfs_chunk *chunk)
3475 {
3476         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
3477         struct map_lookup *map;
3478         struct extent_map *em;
3479         u64 logical;
3480         u64 length;
3481         u64 devid;
3482         u8 uuid[BTRFS_UUID_SIZE];
3483         int num_stripes;
3484         int ret;
3485         int i;
3486
3487         logical = key->offset;
3488         length = btrfs_chunk_length(leaf, chunk);
3489
3490         read_lock(&map_tree->map_tree.lock);
3491         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
3492         read_unlock(&map_tree->map_tree.lock);
3493
3494         /* already mapped? */
3495         if (em && em->start <= logical && em->start + em->len > logical) {
3496                 free_extent_map(em);
3497                 return 0;
3498         } else if (em) {
3499                 free_extent_map(em);
3500         }
3501
3502         em = alloc_extent_map();
3503         if (!em)
3504                 return -ENOMEM;
3505         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3506         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
3507         if (!map) {
3508                 free_extent_map(em);
3509                 return -ENOMEM;
3510         }
3511
3512         em->bdev = (struct block_device *)map;
3513         em->start = logical;
3514         em->len = length;
3515         em->block_start = 0;
3516         em->block_len = em->len;
3517
3518         map->num_stripes = num_stripes;
3519         map->io_width = btrfs_chunk_io_width(leaf, chunk);
3520         map->io_align = btrfs_chunk_io_align(leaf, chunk);
3521         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
3522         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
3523         map->type = btrfs_chunk_type(leaf, chunk);
3524         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
3525         for (i = 0; i < num_stripes; i++) {
3526                 map->stripes[i].physical =
3527                         btrfs_stripe_offset_nr(leaf, chunk, i);
3528                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
3529                 read_extent_buffer(leaf, uuid, (unsigned long)
3530                                    btrfs_stripe_dev_uuid_nr(chunk, i),
3531                                    BTRFS_UUID_SIZE);
3532                 map->stripes[i].dev = btrfs_find_device(root, devid, uuid,
3533                                                         NULL);
3534                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
3535                         kfree(map);
3536                         free_extent_map(em);
3537                         return -EIO;
3538                 }
3539                 if (!map->stripes[i].dev) {
3540                         map->stripes[i].dev =
3541                                 add_missing_dev(root, devid, uuid);
3542                         if (!map->stripes[i].dev) {
3543                                 kfree(map);
3544                                 free_extent_map(em);
3545                                 return -EIO;
3546                         }
3547                 }
3548                 map->stripes[i].dev->in_fs_metadata = 1;
3549         }
3550
3551         write_lock(&map_tree->map_tree.lock);
3552         ret = add_extent_mapping(&map_tree->map_tree, em);
3553         write_unlock(&map_tree->map_tree.lock);
3554         BUG_ON(ret);
3555         free_extent_map(em);
3556
3557         return 0;
3558 }
3559
3560 static int fill_device_from_item(struct extent_buffer *leaf,
3561                                  struct btrfs_dev_item *dev_item,
3562                                  struct btrfs_device *device)
3563 {
3564         unsigned long ptr;
3565
3566         device->devid = btrfs_device_id(leaf, dev_item);
3567         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
3568         device->total_bytes = device->disk_total_bytes;
3569         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
3570         device->type = btrfs_device_type(leaf, dev_item);
3571         device->io_align = btrfs_device_io_align(leaf, dev_item);
3572         device->io_width = btrfs_device_io_width(leaf, dev_item);
3573         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
3574
3575         ptr = (unsigned long)btrfs_device_uuid(dev_item);
3576         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
3577
3578         return 0;
3579 }
3580
3581 static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
3582 {
3583         struct btrfs_fs_devices *fs_devices;
3584         int ret;
3585
3586         mutex_lock(&uuid_mutex);
3587
3588         fs_devices = root->fs_info->fs_devices->seed;
3589         while (fs_devices) {
3590                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
3591                         ret = 0;
3592                         goto out;
3593                 }
3594                 fs_devices = fs_devices->seed;
3595         }
3596
3597         fs_devices = find_fsid(fsid);
3598         if (!fs_devices) {
3599                 ret = -ENOENT;
3600                 goto out;
3601         }
3602
3603         fs_devices = clone_fs_devices(fs_devices);
3604         if (IS_ERR(fs_devices)) {
3605                 ret = PTR_ERR(fs_devices);
3606                 goto out;
3607         }
3608
3609         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
3610                                    root->fs_info->bdev_holder);
3611         if (ret)
3612                 goto out;
3613
3614         if (!fs_devices->seeding) {
3615                 __btrfs_close_devices(fs_devices);
3616                 free_fs_devices(fs_devices);
3617                 ret = -EINVAL;
3618                 goto out;
3619         }
3620
3621         fs_devices->seed = root->fs_info->fs_devices->seed;
3622         root->fs_info->fs_devices->seed = fs_devices;
3623 out:
3624         mutex_unlock(&uuid_mutex);
3625         return ret;
3626 }
3627
3628 static int read_one_dev(struct btrfs_root *root,
3629                         struct extent_buffer *leaf,
3630                         struct btrfs_dev_item *dev_item)
3631 {
3632         struct btrfs_device *device;
3633         u64 devid;
3634         int ret;
3635         u8 fs_uuid[BTRFS_UUID_SIZE];
3636         u8 dev_uuid[BTRFS_UUID_SIZE];
3637
3638         devid = btrfs_device_id(leaf, dev_item);
3639         read_extent_buffer(leaf, dev_uuid,
3640                            (unsigned long)btrfs_device_uuid(dev_item),
3641                            BTRFS_UUID_SIZE);
3642         read_extent_buffer(leaf, fs_uuid,
3643                            (unsigned long)btrfs_device_fsid(dev_item),
3644                            BTRFS_UUID_SIZE);
3645
3646         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
3647                 ret = open_seed_devices(root, fs_uuid);
3648                 if (ret && !btrfs_test_opt(root, DEGRADED))
3649                         return ret;
3650         }
3651
3652         device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
3653         if (!device || !device->bdev) {
3654                 if (!btrfs_test_opt(root, DEGRADED))
3655                         return -EIO;
3656
3657                 if (!device) {
3658                         printk(KERN_WARNING "warning devid %llu missing\n",
3659                                (unsigned long long)devid);
3660                         device = add_missing_dev(root, devid, dev_uuid);
3661                         if (!device)
3662                                 return -ENOMEM;
3663                 } else if (!device->missing) {
3664                         /*
3665                          * this happens when a device that was properly setup
3666                          * in the device info lists suddenly goes bad.
3667                          * device->bdev is NULL, and so we have to set
3668                          * device->missing to one here
3669                          */
3670                         root->fs_info->fs_devices->missing_devices++;
3671                         device->missing = 1;
3672                 }
3673         }
3674
3675         if (device->fs_devices != root->fs_info->fs_devices) {
3676                 BUG_ON(device->writeable);
3677                 if (device->generation !=
3678                     btrfs_device_generation(leaf, dev_item))
3679                         return -EINVAL;
3680         }
3681
3682         fill_device_from_item(leaf, dev_item, device);
3683         device->dev_root = root->fs_info->dev_root;
3684         device->in_fs_metadata = 1;
3685         if (device->writeable)
3686                 device->fs_devices->total_rw_bytes += device->total_bytes;
3687         ret = 0;
3688         return ret;
3689 }
3690
3691 int btrfs_read_super_device(struct btrfs_root *root, struct extent_buffer *buf)
3692 {
3693         struct btrfs_dev_item *dev_item;
3694
3695         dev_item = (struct btrfs_dev_item *)offsetof(struct btrfs_super_block,
3696                                                      dev_item);
3697         return read_one_dev(root, buf, dev_item);
3698 }
3699
3700 int btrfs_read_sys_array(struct btrfs_root *root)
3701 {
3702         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
3703         struct extent_buffer *sb;
3704         struct btrfs_disk_key *disk_key;
3705         struct btrfs_chunk *chunk;
3706         u8 *ptr;
3707         unsigned long sb_ptr;
3708         int ret = 0;
3709         u32 num_stripes;
3710         u32 array_size;
3711         u32 len = 0;
3712         u32 cur;
3713         struct btrfs_key key;
3714
3715         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
3716                                           BTRFS_SUPER_INFO_SIZE);
3717         if (!sb)
3718                 return -ENOMEM;
3719         btrfs_set_buffer_uptodate(sb);
3720         btrfs_set_buffer_lockdep_class(sb, 0);
3721
3722         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
3723         array_size = btrfs_super_sys_array_size(super_copy);
3724
3725         ptr = super_copy->sys_chunk_array;
3726         sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
3727         cur = 0;
3728
3729         while (cur < array_size) {
3730                 disk_key = (struct btrfs_disk_key *)ptr;
3731                 btrfs_disk_key_to_cpu(&key, disk_key);
3732
3733                 len = sizeof(*disk_key); ptr += len;
3734                 sb_ptr += len;
3735                 cur += len;
3736
3737                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
3738                         chunk = (struct btrfs_chunk *)sb_ptr;
3739                         ret = read_one_chunk(root, &key, sb, chunk);
3740                         if (ret)
3741                                 break;
3742                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
3743                         len = btrfs_chunk_item_size(num_stripes);
3744                 } else {
3745                         ret = -EIO;
3746                         break;
3747                 }
3748                 ptr += len;
3749                 sb_ptr += len;
3750                 cur += len;
3751         }
3752         free_extent_buffer(sb);
3753         return ret;
3754 }
3755
3756 int btrfs_read_chunk_tree(struct btrfs_root *root)
3757 {
3758         struct btrfs_path *path;
3759         struct extent_buffer *leaf;
3760         struct btrfs_key key;
3761         struct btrfs_key found_key;
3762         int ret;
3763         int slot;
3764
3765         root = root->fs_info->chunk_root;
3766
3767         path = btrfs_alloc_path();
3768         if (!path)
3769                 return -ENOMEM;
3770
3771         /* first we search for all of the device items, and then we
3772          * read in all of the chunk items.  This way we can create chunk
3773          * mappings that reference all of the devices that are afound
3774          */
3775         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
3776         key.offset = 0;
3777         key.type = 0;
3778 again:
3779         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3780         if (ret < 0)
3781                 goto error;
3782         while (1) {
3783                 leaf = path->nodes[0];
3784                 slot = path->slots[0];
3785                 if (slot >= btrfs_header_nritems(leaf)) {
3786                         ret = btrfs_next_leaf(root, path);
3787                         if (ret == 0)
3788                                 continue;
3789                         if (ret < 0)
3790                                 goto error;
3791                         break;
3792                 }
3793                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3794                 if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
3795                         if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
3796                                 break;
3797                         if (found_key.type == BTRFS_DEV_ITEM_KEY) {
3798                                 struct btrfs_dev_item *dev_item;
3799                                 dev_item = btrfs_item_ptr(leaf, slot,
3800                                                   struct btrfs_dev_item);
3801                                 ret = read_one_dev(root, leaf, dev_item);
3802                                 if (ret)
3803                                         goto error;
3804                         }
3805                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
3806                         struct btrfs_chunk *chunk;
3807                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
3808                         ret = read_one_chunk(root, &found_key, leaf, chunk);
3809                         if (ret)
3810                                 goto error;
3811                 }
3812                 path->slots[0]++;
3813         }
3814         if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
3815                 key.objectid = 0;
3816                 btrfs_release_path(path);
3817                 goto again;
3818         }
3819         ret = 0;
3820 error:
3821         btrfs_free_path(path);
3822         return ret;
3823 }