btrfs-progs: handle invalid num_stripes in sys_array
[platform/upstream/btrfs-progs.git] / 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 <stdio.h>
19 #include <stdlib.h>
20 #include <sys/types.h>
21 #include <sys/stat.h>
22 #include <uuid/uuid.h>
23 #include <fcntl.h>
24 #include <unistd.h>
25 #include "ctree.h"
26 #include "disk-io.h"
27 #include "transaction.h"
28 #include "print-tree.h"
29 #include "volumes.h"
30 #include "utils.h"
31
32 struct stripe {
33         struct btrfs_device *dev;
34         u64 physical;
35 };
36
37 static inline int nr_parity_stripes(struct map_lookup *map)
38 {
39         if (map->type & BTRFS_BLOCK_GROUP_RAID5)
40                 return 1;
41         else if (map->type & BTRFS_BLOCK_GROUP_RAID6)
42                 return 2;
43         else
44                 return 0;
45 }
46
47 static inline int nr_data_stripes(struct map_lookup *map)
48 {
49         return map->num_stripes - nr_parity_stripes(map);
50 }
51
52 #define is_parity_stripe(x) ( ((x) == BTRFS_RAID5_P_STRIPE) || ((x) == BTRFS_RAID6_Q_STRIPE) )
53
54 static LIST_HEAD(fs_uuids);
55
56 static struct btrfs_device *__find_device(struct list_head *head, u64 devid,
57                                           u8 *uuid)
58 {
59         struct btrfs_device *dev;
60         struct list_head *cur;
61
62         list_for_each(cur, head) {
63                 dev = list_entry(cur, struct btrfs_device, dev_list);
64                 if (dev->devid == devid &&
65                     !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE)) {
66                         return dev;
67                 }
68         }
69         return NULL;
70 }
71
72 static struct btrfs_fs_devices *find_fsid(u8 *fsid)
73 {
74         struct list_head *cur;
75         struct btrfs_fs_devices *fs_devices;
76
77         list_for_each(cur, &fs_uuids) {
78                 fs_devices = list_entry(cur, struct btrfs_fs_devices, list);
79                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
80                         return fs_devices;
81         }
82         return NULL;
83 }
84
85 static int device_list_add(const char *path,
86                            struct btrfs_super_block *disk_super,
87                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
88 {
89         struct btrfs_device *device;
90         struct btrfs_fs_devices *fs_devices;
91         u64 found_transid = btrfs_super_generation(disk_super);
92
93         fs_devices = find_fsid(disk_super->fsid);
94         if (!fs_devices) {
95                 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
96                 if (!fs_devices)
97                         return -ENOMEM;
98                 INIT_LIST_HEAD(&fs_devices->devices);
99                 list_add(&fs_devices->list, &fs_uuids);
100                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
101                 fs_devices->latest_devid = devid;
102                 fs_devices->latest_trans = found_transid;
103                 fs_devices->lowest_devid = (u64)-1;
104                 device = NULL;
105         } else {
106                 device = __find_device(&fs_devices->devices, devid,
107                                        disk_super->dev_item.uuid);
108         }
109         if (!device) {
110                 device = kzalloc(sizeof(*device), GFP_NOFS);
111                 if (!device) {
112                         /* we can safely leave the fs_devices entry around */
113                         return -ENOMEM;
114                 }
115                 device->fd = -1;
116                 device->devid = devid;
117                 device->generation = found_transid;
118                 memcpy(device->uuid, disk_super->dev_item.uuid,
119                        BTRFS_UUID_SIZE);
120                 device->name = kstrdup(path, GFP_NOFS);
121                 if (!device->name) {
122                         kfree(device);
123                         return -ENOMEM;
124                 }
125                 device->label = kstrdup(disk_super->label, GFP_NOFS);
126                 if (!device->label) {
127                         kfree(device->name);
128                         kfree(device);
129                         return -ENOMEM;
130                 }
131                 device->total_devs = btrfs_super_num_devices(disk_super);
132                 device->super_bytes_used = btrfs_super_bytes_used(disk_super);
133                 device->total_bytes =
134                         btrfs_stack_device_total_bytes(&disk_super->dev_item);
135                 device->bytes_used =
136                         btrfs_stack_device_bytes_used(&disk_super->dev_item);
137                 list_add(&device->dev_list, &fs_devices->devices);
138                 device->fs_devices = fs_devices;
139         } else if (!device->name || strcmp(device->name, path)) {
140                 char *name = strdup(path);
141                 if (!name)
142                         return -ENOMEM;
143                 kfree(device->name);
144                 device->name = name;
145         }
146
147
148         if (found_transid > fs_devices->latest_trans) {
149                 fs_devices->latest_devid = devid;
150                 fs_devices->latest_trans = found_transid;
151         }
152         if (fs_devices->lowest_devid > devid) {
153                 fs_devices->lowest_devid = devid;
154         }
155         *fs_devices_ret = fs_devices;
156         return 0;
157 }
158
159 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
160 {
161         struct btrfs_fs_devices *seed_devices;
162         struct btrfs_device *device;
163
164 again:
165         while (!list_empty(&fs_devices->devices)) {
166                 device = list_entry(fs_devices->devices.next,
167                                     struct btrfs_device, dev_list);
168                 if (device->fd != -1) {
169                         fsync(device->fd);
170                         if (posix_fadvise(device->fd, 0, 0, POSIX_FADV_DONTNEED))
171                                 fprintf(stderr, "Warning, could not drop caches\n");
172                         close(device->fd);
173                         device->fd = -1;
174                 }
175                 device->writeable = 0;
176                 list_del(&device->dev_list);
177                 /* free the memory */
178                 free(device->name);
179                 free(device->label);
180                 free(device);
181         }
182
183         seed_devices = fs_devices->seed;
184         fs_devices->seed = NULL;
185         if (seed_devices) {
186                 struct btrfs_fs_devices *orig;
187
188                 orig = fs_devices;
189                 fs_devices = seed_devices;
190                 list_del(&orig->list);
191                 free(orig);
192                 goto again;
193         } else {
194                 list_del(&fs_devices->list);
195                 free(fs_devices);
196         }
197
198         return 0;
199 }
200
201 void btrfs_close_all_devices(void)
202 {
203         struct btrfs_fs_devices *fs_devices;
204
205         while (!list_empty(&fs_uuids)) {
206                 fs_devices = list_entry(fs_uuids.next, struct btrfs_fs_devices,
207                                         list);
208                 btrfs_close_devices(fs_devices);
209         }
210 }
211
212 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, int flags)
213 {
214         int fd;
215         struct list_head *head = &fs_devices->devices;
216         struct list_head *cur;
217         struct btrfs_device *device;
218         int ret;
219
220         list_for_each(cur, head) {
221                 device = list_entry(cur, struct btrfs_device, dev_list);
222                 if (!device->name) {
223                         printk("no name for device %llu, skip it now\n", device->devid);
224                         continue;
225                 }
226
227                 fd = open(device->name, flags);
228                 if (fd < 0) {
229                         ret = -errno;
230                         goto fail;
231                 }
232
233                 if (posix_fadvise(fd, 0, 0, POSIX_FADV_DONTNEED))
234                         fprintf(stderr, "Warning, could not drop caches\n");
235
236                 if (device->devid == fs_devices->latest_devid)
237                         fs_devices->latest_bdev = fd;
238                 if (device->devid == fs_devices->lowest_devid)
239                         fs_devices->lowest_bdev = fd;
240                 device->fd = fd;
241                 if (flags & O_RDWR)
242                         device->writeable = 1;
243         }
244         return 0;
245 fail:
246         btrfs_close_devices(fs_devices);
247         return ret;
248 }
249
250 int btrfs_scan_one_device(int fd, const char *path,
251                           struct btrfs_fs_devices **fs_devices_ret,
252                           u64 *total_devs, u64 super_offset, int super_recover)
253 {
254         struct btrfs_super_block *disk_super;
255         char buf[BTRFS_SUPER_INFO_SIZE];
256         int ret;
257         u64 devid;
258
259         disk_super = (struct btrfs_super_block *)buf;
260         ret = btrfs_read_dev_super(fd, disk_super, super_offset, super_recover);
261         if (ret < 0)
262                 return -EIO;
263         devid = btrfs_stack_device_id(&disk_super->dev_item);
264         if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_METADUMP)
265                 *total_devs = 1;
266         else
267                 *total_devs = btrfs_super_num_devices(disk_super);
268
269         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
270
271         return ret;
272 }
273
274 /*
275  * this uses a pretty simple search, the expectation is that it is
276  * called very infrequently and that a given device has a small number
277  * of extents
278  */
279 static int find_free_dev_extent(struct btrfs_trans_handle *trans,
280                                 struct btrfs_device *device,
281                                 struct btrfs_path *path,
282                                 u64 num_bytes, u64 *start)
283 {
284         struct btrfs_key key;
285         struct btrfs_root *root = device->dev_root;
286         struct btrfs_dev_extent *dev_extent = NULL;
287         u64 hole_size = 0;
288         u64 last_byte = 0;
289         u64 search_start = root->fs_info->alloc_start;
290         u64 search_end = device->total_bytes;
291         int ret;
292         int slot = 0;
293         int start_found;
294         struct extent_buffer *l;
295
296         start_found = 0;
297         path->reada = 2;
298
299         /* FIXME use last free of some kind */
300
301         /* we don't want to overwrite the superblock on the drive,
302          * so we make sure to start at an offset of at least 1MB
303          */
304         search_start = max(BTRFS_BLOCK_RESERVED_1M_FOR_SUPER, search_start);
305
306         if (search_start >= search_end) {
307                 ret = -ENOSPC;
308                 goto error;
309         }
310
311         key.objectid = device->devid;
312         key.offset = search_start;
313         key.type = BTRFS_DEV_EXTENT_KEY;
314         ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
315         if (ret < 0)
316                 goto error;
317         ret = btrfs_previous_item(root, path, 0, key.type);
318         if (ret < 0)
319                 goto error;
320         l = path->nodes[0];
321         btrfs_item_key_to_cpu(l, &key, path->slots[0]);
322         while (1) {
323                 l = path->nodes[0];
324                 slot = path->slots[0];
325                 if (slot >= btrfs_header_nritems(l)) {
326                         ret = btrfs_next_leaf(root, path);
327                         if (ret == 0)
328                                 continue;
329                         if (ret < 0)
330                                 goto error;
331 no_more_items:
332                         if (!start_found) {
333                                 if (search_start >= search_end) {
334                                         ret = -ENOSPC;
335                                         goto error;
336                                 }
337                                 *start = search_start;
338                                 start_found = 1;
339                                 goto check_pending;
340                         }
341                         *start = last_byte > search_start ?
342                                 last_byte : search_start;
343                         if (search_end <= *start) {
344                                 ret = -ENOSPC;
345                                 goto error;
346                         }
347                         goto check_pending;
348                 }
349                 btrfs_item_key_to_cpu(l, &key, slot);
350
351                 if (key.objectid < device->devid)
352                         goto next;
353
354                 if (key.objectid > device->devid)
355                         goto no_more_items;
356
357                 if (key.offset >= search_start && key.offset > last_byte &&
358                     start_found) {
359                         if (last_byte < search_start)
360                                 last_byte = search_start;
361                         hole_size = key.offset - last_byte;
362                         if (key.offset > last_byte &&
363                             hole_size >= num_bytes) {
364                                 *start = last_byte;
365                                 goto check_pending;
366                         }
367                 }
368                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY) {
369                         goto next;
370                 }
371
372                 start_found = 1;
373                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
374                 last_byte = key.offset + btrfs_dev_extent_length(l, dev_extent);
375 next:
376                 path->slots[0]++;
377                 cond_resched();
378         }
379 check_pending:
380         /* we have to make sure we didn't find an extent that has already
381          * been allocated by the map tree or the original allocation
382          */
383         btrfs_release_path(path);
384         BUG_ON(*start < search_start);
385
386         if (*start + num_bytes > search_end) {
387                 ret = -ENOSPC;
388                 goto error;
389         }
390         /* check for pending inserts here */
391         return 0;
392
393 error:
394         btrfs_release_path(path);
395         return ret;
396 }
397
398 static int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
399                                   struct btrfs_device *device,
400                                   u64 chunk_tree, u64 chunk_objectid,
401                                   u64 chunk_offset,
402                                   u64 num_bytes, u64 *start)
403 {
404         int ret;
405         struct btrfs_path *path;
406         struct btrfs_root *root = device->dev_root;
407         struct btrfs_dev_extent *extent;
408         struct extent_buffer *leaf;
409         struct btrfs_key key;
410
411         path = btrfs_alloc_path();
412         if (!path)
413                 return -ENOMEM;
414
415         ret = find_free_dev_extent(trans, device, path, num_bytes, start);
416         if (ret) {
417                 goto err;
418         }
419
420         key.objectid = device->devid;
421         key.offset = *start;
422         key.type = BTRFS_DEV_EXTENT_KEY;
423         ret = btrfs_insert_empty_item(trans, root, path, &key,
424                                       sizeof(*extent));
425         BUG_ON(ret);
426
427         leaf = path->nodes[0];
428         extent = btrfs_item_ptr(leaf, path->slots[0],
429                                 struct btrfs_dev_extent);
430         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
431         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
432         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
433
434         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
435                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
436                     BTRFS_UUID_SIZE);
437
438         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
439         btrfs_mark_buffer_dirty(leaf);
440 err:
441         btrfs_free_path(path);
442         return ret;
443 }
444
445 static int find_next_chunk(struct btrfs_root *root, u64 objectid, u64 *offset)
446 {
447         struct btrfs_path *path;
448         int ret;
449         struct btrfs_key key;
450         struct btrfs_chunk *chunk;
451         struct btrfs_key found_key;
452
453         path = btrfs_alloc_path();
454         BUG_ON(!path);
455
456         key.objectid = objectid;
457         key.offset = (u64)-1;
458         key.type = BTRFS_CHUNK_ITEM_KEY;
459
460         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
461         if (ret < 0)
462                 goto error;
463
464         BUG_ON(ret == 0);
465
466         ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
467         if (ret) {
468                 *offset = 0;
469         } else {
470                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
471                                       path->slots[0]);
472                 if (found_key.objectid != objectid)
473                         *offset = 0;
474                 else {
475                         chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
476                                                struct btrfs_chunk);
477                         *offset = found_key.offset +
478                                 btrfs_chunk_length(path->nodes[0], chunk);
479                 }
480         }
481         ret = 0;
482 error:
483         btrfs_free_path(path);
484         return ret;
485 }
486
487 static int find_next_devid(struct btrfs_root *root, struct btrfs_path *path,
488                            u64 *objectid)
489 {
490         int ret;
491         struct btrfs_key key;
492         struct btrfs_key found_key;
493
494         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
495         key.type = BTRFS_DEV_ITEM_KEY;
496         key.offset = (u64)-1;
497
498         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
499         if (ret < 0)
500                 goto error;
501
502         BUG_ON(ret == 0);
503
504         ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
505                                   BTRFS_DEV_ITEM_KEY);
506         if (ret) {
507                 *objectid = 1;
508         } else {
509                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
510                                       path->slots[0]);
511                 *objectid = found_key.offset + 1;
512         }
513         ret = 0;
514 error:
515         btrfs_release_path(path);
516         return ret;
517 }
518
519 /*
520  * the device information is stored in the chunk root
521  * the btrfs_device struct should be fully filled in
522  */
523 int btrfs_add_device(struct btrfs_trans_handle *trans,
524                      struct btrfs_root *root,
525                      struct btrfs_device *device)
526 {
527         int ret;
528         struct btrfs_path *path;
529         struct btrfs_dev_item *dev_item;
530         struct extent_buffer *leaf;
531         struct btrfs_key key;
532         unsigned long ptr;
533         u64 free_devid = 0;
534
535         root = root->fs_info->chunk_root;
536
537         path = btrfs_alloc_path();
538         if (!path)
539                 return -ENOMEM;
540
541         ret = find_next_devid(root, path, &free_devid);
542         if (ret)
543                 goto out;
544
545         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
546         key.type = BTRFS_DEV_ITEM_KEY;
547         key.offset = free_devid;
548
549         ret = btrfs_insert_empty_item(trans, root, path, &key,
550                                       sizeof(*dev_item));
551         if (ret)
552                 goto out;
553
554         leaf = path->nodes[0];
555         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
556
557         device->devid = free_devid;
558         btrfs_set_device_id(leaf, dev_item, device->devid);
559         btrfs_set_device_generation(leaf, dev_item, 0);
560         btrfs_set_device_type(leaf, dev_item, device->type);
561         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
562         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
563         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
564         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
565         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
566         btrfs_set_device_group(leaf, dev_item, 0);
567         btrfs_set_device_seek_speed(leaf, dev_item, 0);
568         btrfs_set_device_bandwidth(leaf, dev_item, 0);
569         btrfs_set_device_start_offset(leaf, dev_item, 0);
570
571         ptr = (unsigned long)btrfs_device_uuid(dev_item);
572         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
573         ptr = (unsigned long)btrfs_device_fsid(dev_item);
574         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
575         btrfs_mark_buffer_dirty(leaf);
576         ret = 0;
577
578 out:
579         btrfs_free_path(path);
580         return ret;
581 }
582
583 int btrfs_update_device(struct btrfs_trans_handle *trans,
584                         struct btrfs_device *device)
585 {
586         int ret;
587         struct btrfs_path *path;
588         struct btrfs_root *root;
589         struct btrfs_dev_item *dev_item;
590         struct extent_buffer *leaf;
591         struct btrfs_key key;
592
593         root = device->dev_root->fs_info->chunk_root;
594
595         path = btrfs_alloc_path();
596         if (!path)
597                 return -ENOMEM;
598
599         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
600         key.type = BTRFS_DEV_ITEM_KEY;
601         key.offset = device->devid;
602
603         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
604         if (ret < 0)
605                 goto out;
606
607         if (ret > 0) {
608                 ret = -ENOENT;
609                 goto out;
610         }
611
612         leaf = path->nodes[0];
613         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
614
615         btrfs_set_device_id(leaf, dev_item, device->devid);
616         btrfs_set_device_type(leaf, dev_item, device->type);
617         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
618         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
619         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
620         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
621         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
622         btrfs_mark_buffer_dirty(leaf);
623
624 out:
625         btrfs_free_path(path);
626         return ret;
627 }
628
629 int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
630                            struct btrfs_root *root,
631                            struct btrfs_key *key,
632                            struct btrfs_chunk *chunk, int item_size)
633 {
634         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
635         struct btrfs_disk_key disk_key;
636         u32 array_size;
637         u8 *ptr;
638
639         array_size = btrfs_super_sys_array_size(super_copy);
640         if (array_size + item_size + sizeof(disk_key)
641                         > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
642                 return -EFBIG;
643
644         ptr = super_copy->sys_chunk_array + array_size;
645         btrfs_cpu_key_to_disk(&disk_key, key);
646         memcpy(ptr, &disk_key, sizeof(disk_key));
647         ptr += sizeof(disk_key);
648         memcpy(ptr, chunk, item_size);
649         item_size += sizeof(disk_key);
650         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
651         return 0;
652 }
653
654 static u64 chunk_bytes_by_type(u64 type, u64 calc_size, int num_stripes,
655                                int sub_stripes)
656 {
657         if (type & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_DUP))
658                 return calc_size;
659         else if (type & BTRFS_BLOCK_GROUP_RAID10)
660                 return calc_size * (num_stripes / sub_stripes);
661         else if (type & BTRFS_BLOCK_GROUP_RAID5)
662                 return calc_size * (num_stripes - 1);
663         else if (type & BTRFS_BLOCK_GROUP_RAID6)
664                 return calc_size * (num_stripes - 2);
665         else
666                 return calc_size * num_stripes;
667 }
668
669
670 static u32 find_raid56_stripe_len(u32 data_devices, u32 dev_stripe_target)
671 {
672         /* TODO, add a way to store the preferred stripe size */
673         return BTRFS_STRIPE_LEN;
674 }
675
676 /*
677  * btrfs_device_avail_bytes - count bytes available for alloc_chunk
678  *
679  * It is not equal to "device->total_bytes - device->bytes_used".
680  * We do not allocate any chunk in 1M at beginning of device, and not
681  * allowed to allocate any chunk before alloc_start if it is specified.
682  * So search holes from max(1M, alloc_start) to device->total_bytes.
683  */
684 static int btrfs_device_avail_bytes(struct btrfs_trans_handle *trans,
685                                     struct btrfs_device *device,
686                                     u64 *avail_bytes)
687 {
688         struct btrfs_path *path;
689         struct btrfs_root *root = device->dev_root;
690         struct btrfs_key key;
691         struct btrfs_dev_extent *dev_extent = NULL;
692         struct extent_buffer *l;
693         u64 search_start = root->fs_info->alloc_start;
694         u64 search_end = device->total_bytes;
695         u64 extent_end = 0;
696         u64 free_bytes = 0;
697         int ret;
698         int slot = 0;
699
700         search_start = max(BTRFS_BLOCK_RESERVED_1M_FOR_SUPER, search_start);
701
702         path = btrfs_alloc_path();
703         if (!path)
704                 return -ENOMEM;
705
706         key.objectid = device->devid;
707         key.offset = root->fs_info->alloc_start;
708         key.type = BTRFS_DEV_EXTENT_KEY;
709
710         path->reada = 2;
711         ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
712         if (ret < 0)
713                 goto error;
714         ret = btrfs_previous_item(root, path, 0, key.type);
715         if (ret < 0)
716                 goto error;
717
718         while (1) {
719                 l = path->nodes[0];
720                 slot = path->slots[0];
721                 if (slot >= btrfs_header_nritems(l)) {
722                         ret = btrfs_next_leaf(root, path);
723                         if (ret == 0)
724                                 continue;
725                         if (ret < 0)
726                                 goto error;
727                         break;
728                 }
729                 btrfs_item_key_to_cpu(l, &key, slot);
730
731                 if (key.objectid < device->devid)
732                         goto next;
733                 if (key.objectid > device->devid)
734                         break;
735                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
736                         goto next;
737                 if (key.offset > search_end)
738                         break;
739                 if (key.offset > search_start)
740                         free_bytes += key.offset - search_start;
741
742                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
743                 extent_end = key.offset + btrfs_dev_extent_length(l,
744                                                                   dev_extent);
745                 if (extent_end > search_start)
746                         search_start = extent_end;
747                 if (search_start > search_end)
748                         break;
749 next:
750                 path->slots[0]++;
751                 cond_resched();
752         }
753
754         if (search_start < search_end)
755                 free_bytes += search_end - search_start;
756
757         *avail_bytes = free_bytes;
758         ret = 0;
759 error:
760         btrfs_free_path(path);
761         return ret;
762 }
763
764 #define BTRFS_MAX_DEVS(r) ((BTRFS_LEAF_DATA_SIZE(r)             \
765                         - sizeof(struct btrfs_item)             \
766                         - sizeof(struct btrfs_chunk))           \
767                         / sizeof(struct btrfs_stripe) + 1)
768
769 #define BTRFS_MAX_DEVS_SYS_CHUNK ((BTRFS_SYSTEM_CHUNK_ARRAY_SIZE        \
770                                 - 2 * sizeof(struct btrfs_disk_key)     \
771                                 - 2 * sizeof(struct btrfs_chunk))       \
772                                 / sizeof(struct btrfs_stripe) + 1)
773
774 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
775                       struct btrfs_root *extent_root, u64 *start,
776                       u64 *num_bytes, u64 type)
777 {
778         u64 dev_offset;
779         struct btrfs_fs_info *info = extent_root->fs_info;
780         struct btrfs_root *chunk_root = info->chunk_root;
781         struct btrfs_stripe *stripes;
782         struct btrfs_device *device = NULL;
783         struct btrfs_chunk *chunk;
784         struct list_head private_devs;
785         struct list_head *dev_list = &info->fs_devices->devices;
786         struct list_head *cur;
787         struct map_lookup *map;
788         int min_stripe_size = 1 * 1024 * 1024;
789         u64 calc_size = 8 * 1024 * 1024;
790         u64 min_free;
791         u64 max_chunk_size = 4 * calc_size;
792         u64 avail = 0;
793         u64 max_avail = 0;
794         u64 percent_max;
795         int num_stripes = 1;
796         int max_stripes = 0;
797         int min_stripes = 1;
798         int sub_stripes = 0;
799         int looped = 0;
800         int ret;
801         int index;
802         int stripe_len = BTRFS_STRIPE_LEN;
803         struct btrfs_key key;
804         u64 offset;
805
806         if (list_empty(dev_list)) {
807                 return -ENOSPC;
808         }
809
810         if (type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
811                     BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
812                     BTRFS_BLOCK_GROUP_RAID10 |
813                     BTRFS_BLOCK_GROUP_DUP)) {
814                 if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
815                         calc_size = 8 * 1024 * 1024;
816                         max_chunk_size = calc_size * 2;
817                         min_stripe_size = 1 * 1024 * 1024;
818                         max_stripes = BTRFS_MAX_DEVS_SYS_CHUNK;
819                 } else if (type & BTRFS_BLOCK_GROUP_DATA) {
820                         calc_size = 1024 * 1024 * 1024;
821                         max_chunk_size = 10 * calc_size;
822                         min_stripe_size = 64 * 1024 * 1024;
823                         max_stripes = BTRFS_MAX_DEVS(chunk_root);
824                 } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
825                         calc_size = 1024 * 1024 * 1024;
826                         max_chunk_size = 4 * calc_size;
827                         min_stripe_size = 32 * 1024 * 1024;
828                         max_stripes = BTRFS_MAX_DEVS(chunk_root);
829                 }
830         }
831         if (type & BTRFS_BLOCK_GROUP_RAID1) {
832                 num_stripes = min_t(u64, 2,
833                                   btrfs_super_num_devices(info->super_copy));
834                 if (num_stripes < 2)
835                         return -ENOSPC;
836                 min_stripes = 2;
837         }
838         if (type & BTRFS_BLOCK_GROUP_DUP) {
839                 num_stripes = 2;
840                 min_stripes = 2;
841         }
842         if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
843                 num_stripes = btrfs_super_num_devices(info->super_copy);
844                 if (num_stripes > max_stripes)
845                         num_stripes = max_stripes;
846                 min_stripes = 2;
847         }
848         if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
849                 num_stripes = btrfs_super_num_devices(info->super_copy);
850                 if (num_stripes > max_stripes)
851                         num_stripes = max_stripes;
852                 if (num_stripes < 4)
853                         return -ENOSPC;
854                 num_stripes &= ~(u32)1;
855                 sub_stripes = 2;
856                 min_stripes = 4;
857         }
858         if (type & (BTRFS_BLOCK_GROUP_RAID5)) {
859                 num_stripes = btrfs_super_num_devices(info->super_copy);
860                 if (num_stripes > max_stripes)
861                         num_stripes = max_stripes;
862                 if (num_stripes < 2)
863                         return -ENOSPC;
864                 min_stripes = 2;
865                 stripe_len = find_raid56_stripe_len(num_stripes - 1,
866                                     btrfs_super_stripesize(info->super_copy));
867         }
868         if (type & (BTRFS_BLOCK_GROUP_RAID6)) {
869                 num_stripes = btrfs_super_num_devices(info->super_copy);
870                 if (num_stripes > max_stripes)
871                         num_stripes = max_stripes;
872                 if (num_stripes < 3)
873                         return -ENOSPC;
874                 min_stripes = 3;
875                 stripe_len = find_raid56_stripe_len(num_stripes - 2,
876                                     btrfs_super_stripesize(info->super_copy));
877         }
878
879         /* we don't want a chunk larger than 10% of the FS */
880         percent_max = div_factor(btrfs_super_total_bytes(info->super_copy), 1);
881         max_chunk_size = min(percent_max, max_chunk_size);
882
883 again:
884         if (chunk_bytes_by_type(type, calc_size, num_stripes, sub_stripes) >
885             max_chunk_size) {
886                 calc_size = max_chunk_size;
887                 calc_size /= num_stripes;
888                 calc_size /= stripe_len;
889                 calc_size *= stripe_len;
890         }
891         /* we don't want tiny stripes */
892         calc_size = max_t(u64, calc_size, min_stripe_size);
893
894         calc_size /= stripe_len;
895         calc_size *= stripe_len;
896         INIT_LIST_HEAD(&private_devs);
897         cur = dev_list->next;
898         index = 0;
899
900         if (type & BTRFS_BLOCK_GROUP_DUP)
901                 min_free = calc_size * 2;
902         else
903                 min_free = calc_size;
904
905         /* build a private list of devices we will allocate from */
906         while(index < num_stripes) {
907                 device = list_entry(cur, struct btrfs_device, dev_list);
908                 ret = btrfs_device_avail_bytes(trans, device, &avail);
909                 if (ret)
910                         return ret;
911                 cur = cur->next;
912                 if (avail >= min_free) {
913                         list_move_tail(&device->dev_list, &private_devs);
914                         index++;
915                         if (type & BTRFS_BLOCK_GROUP_DUP)
916                                 index++;
917                 } else if (avail > max_avail)
918                         max_avail = avail;
919                 if (cur == dev_list)
920                         break;
921         }
922         if (index < num_stripes) {
923                 list_splice(&private_devs, dev_list);
924                 if (index >= min_stripes) {
925                         num_stripes = index;
926                         if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
927                                 num_stripes /= sub_stripes;
928                                 num_stripes *= sub_stripes;
929                         }
930                         looped = 1;
931                         goto again;
932                 }
933                 if (!looped && max_avail > 0) {
934                         looped = 1;
935                         calc_size = max_avail;
936                         goto again;
937                 }
938                 return -ENOSPC;
939         }
940         ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
941                               &offset);
942         if (ret)
943                 return ret;
944         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
945         key.type = BTRFS_CHUNK_ITEM_KEY;
946         key.offset = offset;
947
948         chunk = kmalloc(btrfs_chunk_item_size(num_stripes), GFP_NOFS);
949         if (!chunk)
950                 return -ENOMEM;
951
952         map = kmalloc(btrfs_map_lookup_size(num_stripes), GFP_NOFS);
953         if (!map) {
954                 kfree(chunk);
955                 return -ENOMEM;
956         }
957
958         stripes = &chunk->stripe;
959         *num_bytes = chunk_bytes_by_type(type, calc_size,
960                                          num_stripes, sub_stripes);
961         index = 0;
962         while(index < num_stripes) {
963                 struct btrfs_stripe *stripe;
964                 BUG_ON(list_empty(&private_devs));
965                 cur = private_devs.next;
966                 device = list_entry(cur, struct btrfs_device, dev_list);
967
968                 /* loop over this device again if we're doing a dup group */
969                 if (!(type & BTRFS_BLOCK_GROUP_DUP) ||
970                     (index == num_stripes - 1))
971                         list_move_tail(&device->dev_list, dev_list);
972
973                 ret = btrfs_alloc_dev_extent(trans, device,
974                              info->chunk_root->root_key.objectid,
975                              BTRFS_FIRST_CHUNK_TREE_OBJECTID, key.offset,
976                              calc_size, &dev_offset);
977                 BUG_ON(ret);
978
979                 device->bytes_used += calc_size;
980                 ret = btrfs_update_device(trans, device);
981                 BUG_ON(ret);
982
983                 map->stripes[index].dev = device;
984                 map->stripes[index].physical = dev_offset;
985                 stripe = stripes + index;
986                 btrfs_set_stack_stripe_devid(stripe, device->devid);
987                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
988                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
989                 index++;
990         }
991         BUG_ON(!list_empty(&private_devs));
992
993         /* key was set above */
994         btrfs_set_stack_chunk_length(chunk, *num_bytes);
995         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
996         btrfs_set_stack_chunk_stripe_len(chunk, stripe_len);
997         btrfs_set_stack_chunk_type(chunk, type);
998         btrfs_set_stack_chunk_num_stripes(chunk, num_stripes);
999         btrfs_set_stack_chunk_io_align(chunk, stripe_len);
1000         btrfs_set_stack_chunk_io_width(chunk, stripe_len);
1001         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
1002         btrfs_set_stack_chunk_sub_stripes(chunk, sub_stripes);
1003         map->sector_size = extent_root->sectorsize;
1004         map->stripe_len = stripe_len;
1005         map->io_align = stripe_len;
1006         map->io_width = stripe_len;
1007         map->type = type;
1008         map->num_stripes = num_stripes;
1009         map->sub_stripes = sub_stripes;
1010
1011         ret = btrfs_insert_item(trans, chunk_root, &key, chunk,
1012                                 btrfs_chunk_item_size(num_stripes));
1013         BUG_ON(ret);
1014         *start = key.offset;;
1015
1016         map->ce.start = key.offset;
1017         map->ce.size = *num_bytes;
1018
1019         ret = insert_cache_extent(&info->mapping_tree.cache_tree, &map->ce);
1020         BUG_ON(ret);
1021
1022         if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
1023                 ret = btrfs_add_system_chunk(trans, chunk_root, &key,
1024                                     chunk, btrfs_chunk_item_size(num_stripes));
1025                 BUG_ON(ret);
1026         }
1027
1028         kfree(chunk);
1029         return ret;
1030 }
1031
1032 int btrfs_alloc_data_chunk(struct btrfs_trans_handle *trans,
1033                            struct btrfs_root *extent_root, u64 *start,
1034                            u64 num_bytes, u64 type)
1035 {
1036         u64 dev_offset;
1037         struct btrfs_fs_info *info = extent_root->fs_info;
1038         struct btrfs_root *chunk_root = info->chunk_root;
1039         struct btrfs_stripe *stripes;
1040         struct btrfs_device *device = NULL;
1041         struct btrfs_chunk *chunk;
1042         struct list_head *dev_list = &info->fs_devices->devices;
1043         struct list_head *cur;
1044         struct map_lookup *map;
1045         u64 calc_size = 8 * 1024 * 1024;
1046         int num_stripes = 1;
1047         int sub_stripes = 0;
1048         int ret;
1049         int index;
1050         int stripe_len = BTRFS_STRIPE_LEN;
1051         struct btrfs_key key;
1052
1053         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
1054         key.type = BTRFS_CHUNK_ITEM_KEY;
1055         ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
1056                               &key.offset);
1057         if (ret)
1058                 return ret;
1059
1060         chunk = kmalloc(btrfs_chunk_item_size(num_stripes), GFP_NOFS);
1061         if (!chunk)
1062                 return -ENOMEM;
1063
1064         map = kmalloc(btrfs_map_lookup_size(num_stripes), GFP_NOFS);
1065         if (!map) {
1066                 kfree(chunk);
1067                 return -ENOMEM;
1068         }
1069
1070         stripes = &chunk->stripe;
1071         calc_size = num_bytes;
1072
1073         index = 0;
1074         cur = dev_list->next;
1075         device = list_entry(cur, struct btrfs_device, dev_list);
1076
1077         while (index < num_stripes) {
1078                 struct btrfs_stripe *stripe;
1079
1080                 ret = btrfs_alloc_dev_extent(trans, device,
1081                              info->chunk_root->root_key.objectid,
1082                              BTRFS_FIRST_CHUNK_TREE_OBJECTID, key.offset,
1083                              calc_size, &dev_offset);
1084                 BUG_ON(ret);
1085
1086                 device->bytes_used += calc_size;
1087                 ret = btrfs_update_device(trans, device);
1088                 BUG_ON(ret);
1089
1090                 map->stripes[index].dev = device;
1091                 map->stripes[index].physical = dev_offset;
1092                 stripe = stripes + index;
1093                 btrfs_set_stack_stripe_devid(stripe, device->devid);
1094                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
1095                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
1096                 index++;
1097         }
1098
1099         /* key was set above */
1100         btrfs_set_stack_chunk_length(chunk, num_bytes);
1101         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
1102         btrfs_set_stack_chunk_stripe_len(chunk, stripe_len);
1103         btrfs_set_stack_chunk_type(chunk, type);
1104         btrfs_set_stack_chunk_num_stripes(chunk, num_stripes);
1105         btrfs_set_stack_chunk_io_align(chunk, stripe_len);
1106         btrfs_set_stack_chunk_io_width(chunk, stripe_len);
1107         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
1108         btrfs_set_stack_chunk_sub_stripes(chunk, sub_stripes);
1109         map->sector_size = extent_root->sectorsize;
1110         map->stripe_len = stripe_len;
1111         map->io_align = stripe_len;
1112         map->io_width = stripe_len;
1113         map->type = type;
1114         map->num_stripes = num_stripes;
1115         map->sub_stripes = sub_stripes;
1116
1117         ret = btrfs_insert_item(trans, chunk_root, &key, chunk,
1118                                 btrfs_chunk_item_size(num_stripes));
1119         BUG_ON(ret);
1120         *start = key.offset;
1121
1122         map->ce.start = key.offset;
1123         map->ce.size = num_bytes;
1124
1125         ret = insert_cache_extent(&info->mapping_tree.cache_tree, &map->ce);
1126         BUG_ON(ret);
1127
1128         kfree(chunk);
1129         return ret;
1130 }
1131
1132 int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
1133 {
1134         struct cache_extent *ce;
1135         struct map_lookup *map;
1136         int ret;
1137
1138         ce = search_cache_extent(&map_tree->cache_tree, logical);
1139         if (!ce) {
1140                 fprintf(stderr, "No mapping for %llu-%llu\n",
1141                         (unsigned long long)logical,
1142                         (unsigned long long)logical+len);
1143                 return 1;
1144         }
1145         if (ce->start > logical || ce->start + ce->size < logical) {
1146                 fprintf(stderr, "Invalid mapping for %llu-%llu, got "
1147                         "%llu-%llu\n", (unsigned long long)logical,
1148                         (unsigned long long)logical+len,
1149                         (unsigned long long)ce->start,
1150                         (unsigned long long)ce->start + ce->size);
1151                 return 1;
1152         }
1153         map = container_of(ce, struct map_lookup, ce);
1154
1155         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
1156                 ret = map->num_stripes;
1157         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
1158                 ret = map->sub_stripes;
1159         else if (map->type & BTRFS_BLOCK_GROUP_RAID5)
1160                 ret = 2;
1161         else if (map->type & BTRFS_BLOCK_GROUP_RAID6)
1162                 ret = 3;
1163         else
1164                 ret = 1;
1165         return ret;
1166 }
1167
1168 int btrfs_next_bg(struct btrfs_mapping_tree *map_tree, u64 *logical,
1169                      u64 *size, u64 type)
1170 {
1171         struct cache_extent *ce;
1172         struct map_lookup *map;
1173
1174         ce = search_cache_extent(&map_tree->cache_tree, *logical);
1175
1176         while (ce) {
1177                 ce = next_cache_extent(ce);
1178                 if (!ce)
1179                         return -ENOENT;
1180
1181                 map = container_of(ce, struct map_lookup, ce);
1182                 if (map->type & type) {
1183                         *logical = ce->start;
1184                         *size = ce->size;
1185                         return 0;
1186                 }
1187         }
1188
1189         return -ENOENT;
1190 }
1191
1192 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
1193                      u64 chunk_start, u64 physical, u64 devid,
1194                      u64 **logical, int *naddrs, int *stripe_len)
1195 {
1196         struct cache_extent *ce;
1197         struct map_lookup *map;
1198         u64 *buf;
1199         u64 bytenr;
1200         u64 length;
1201         u64 stripe_nr;
1202         u64 rmap_len;
1203         int i, j, nr = 0;
1204
1205         ce = search_cache_extent(&map_tree->cache_tree, chunk_start);
1206         BUG_ON(!ce);
1207         map = container_of(ce, struct map_lookup, ce);
1208
1209         length = ce->size;
1210         rmap_len = map->stripe_len;
1211         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
1212                 length = ce->size / (map->num_stripes / map->sub_stripes);
1213         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
1214                 length = ce->size / map->num_stripes;
1215         else if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
1216                               BTRFS_BLOCK_GROUP_RAID6)) {
1217                 length = ce->size / nr_data_stripes(map);
1218                 rmap_len = map->stripe_len * nr_data_stripes(map);
1219         }
1220
1221         buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
1222
1223         for (i = 0; i < map->num_stripes; i++) {
1224                 if (devid && map->stripes[i].dev->devid != devid)
1225                         continue;
1226                 if (map->stripes[i].physical > physical ||
1227                     map->stripes[i].physical + length <= physical)
1228                         continue;
1229
1230                 stripe_nr = (physical - map->stripes[i].physical) /
1231                             map->stripe_len;
1232
1233                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1234                         stripe_nr = (stripe_nr * map->num_stripes + i) /
1235                                     map->sub_stripes;
1236                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
1237                         stripe_nr = stripe_nr * map->num_stripes + i;
1238                 } /* else if RAID[56], multiply by nr_data_stripes().
1239                    * Alternatively, just use rmap_len below instead of
1240                    * map->stripe_len */
1241
1242                 bytenr = ce->start + stripe_nr * rmap_len;
1243                 for (j = 0; j < nr; j++) {
1244                         if (buf[j] == bytenr)
1245                                 break;
1246                 }
1247                 if (j == nr)
1248                         buf[nr++] = bytenr;
1249         }
1250
1251         *logical = buf;
1252         *naddrs = nr;
1253         *stripe_len = rmap_len;
1254
1255         return 0;
1256 }
1257
1258 static inline int parity_smaller(u64 a, u64 b)
1259 {
1260         return a > b;
1261 }
1262
1263 /* Bubble-sort the stripe set to put the parity/syndrome stripes last */
1264 static void sort_parity_stripes(struct btrfs_multi_bio *bbio, u64 *raid_map)
1265 {
1266         struct btrfs_bio_stripe s;
1267         int i;
1268         u64 l;
1269         int again = 1;
1270
1271         while (again) {
1272                 again = 0;
1273                 for (i = 0; i < bbio->num_stripes - 1; i++) {
1274                         if (parity_smaller(raid_map[i], raid_map[i+1])) {
1275                                 s = bbio->stripes[i];
1276                                 l = raid_map[i];
1277                                 bbio->stripes[i] = bbio->stripes[i+1];
1278                                 raid_map[i] = raid_map[i+1];
1279                                 bbio->stripes[i+1] = s;
1280                                 raid_map[i+1] = l;
1281                                 again = 1;
1282                         }
1283                 }
1284         }
1285 }
1286
1287 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
1288                     u64 logical, u64 *length,
1289                     struct btrfs_multi_bio **multi_ret, int mirror_num,
1290                     u64 **raid_map_ret)
1291 {
1292         return __btrfs_map_block(map_tree, rw, logical, length, NULL,
1293                                  multi_ret, mirror_num, raid_map_ret);
1294 }
1295
1296 int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
1297                     u64 logical, u64 *length, u64 *type,
1298                     struct btrfs_multi_bio **multi_ret, int mirror_num,
1299                     u64 **raid_map_ret)
1300 {
1301         struct cache_extent *ce;
1302         struct map_lookup *map;
1303         u64 offset;
1304         u64 stripe_offset;
1305         u64 stripe_nr;
1306         u64 *raid_map = NULL;
1307         int stripes_allocated = 8;
1308         int stripes_required = 1;
1309         int stripe_index;
1310         int i;
1311         struct btrfs_multi_bio *multi = NULL;
1312
1313         if (multi_ret && rw == READ) {
1314                 stripes_allocated = 1;
1315         }
1316 again:
1317         ce = search_cache_extent(&map_tree->cache_tree, logical);
1318         if (!ce) {
1319                 kfree(multi);
1320                 *length = (u64)-1;
1321                 return -ENOENT;
1322         }
1323         if (ce->start > logical) {
1324                 kfree(multi);
1325                 *length = ce->start - logical;
1326                 return -ENOENT;
1327         }
1328
1329         if (multi_ret) {
1330                 multi = kzalloc(btrfs_multi_bio_size(stripes_allocated),
1331                                 GFP_NOFS);
1332                 if (!multi)
1333                         return -ENOMEM;
1334         }
1335         map = container_of(ce, struct map_lookup, ce);
1336         offset = logical - ce->start;
1337
1338         if (rw == WRITE) {
1339                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
1340                                  BTRFS_BLOCK_GROUP_DUP)) {
1341                         stripes_required = map->num_stripes;
1342                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1343                         stripes_required = map->sub_stripes;
1344                 }
1345         }
1346         if (map->type & (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6)
1347             && multi_ret && ((rw & WRITE) || mirror_num > 1) && raid_map_ret) {
1348                     /* RAID[56] write or recovery. Return all stripes */
1349                     stripes_required = map->num_stripes;
1350
1351                     /* Only allocate the map if we've already got a large enough multi_ret */
1352                     if (stripes_allocated >= stripes_required) {
1353                             raid_map = kmalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
1354                             if (!raid_map) {
1355                                     kfree(multi);
1356                                     return -ENOMEM;
1357                             }
1358                     }
1359         }
1360
1361         /* if our multi bio struct is too small, back off and try again */
1362         if (multi_ret && stripes_allocated < stripes_required) {
1363                 stripes_allocated = stripes_required;
1364                 kfree(multi);
1365                 multi = NULL;
1366                 goto again;
1367         }
1368         stripe_nr = offset;
1369         /*
1370          * stripe_nr counts the total number of stripes we have to stride
1371          * to get to this block
1372          */
1373         stripe_nr = stripe_nr / map->stripe_len;
1374
1375         stripe_offset = stripe_nr * map->stripe_len;
1376         BUG_ON(offset < stripe_offset);
1377
1378         /* stripe_offset is the offset of this block in its stripe*/
1379         stripe_offset = offset - stripe_offset;
1380
1381         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
1382                          BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
1383                          BTRFS_BLOCK_GROUP_RAID10 |
1384                          BTRFS_BLOCK_GROUP_DUP)) {
1385                 /* we limit the length of each bio to what fits in a stripe */
1386                 *length = min_t(u64, ce->size - offset,
1387                               map->stripe_len - stripe_offset);
1388         } else {
1389                 *length = ce->size - offset;
1390         }
1391
1392         if (!multi_ret)
1393                 goto out;
1394
1395         multi->num_stripes = 1;
1396         stripe_index = 0;
1397         if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
1398                 if (rw == WRITE)
1399                         multi->num_stripes = map->num_stripes;
1400                 else if (mirror_num)
1401                         stripe_index = mirror_num - 1;
1402                 else
1403                         stripe_index = stripe_nr % map->num_stripes;
1404         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1405                 int factor = map->num_stripes / map->sub_stripes;
1406
1407                 stripe_index = stripe_nr % factor;
1408                 stripe_index *= map->sub_stripes;
1409
1410                 if (rw == WRITE)
1411                         multi->num_stripes = map->sub_stripes;
1412                 else if (mirror_num)
1413                         stripe_index += mirror_num - 1;
1414
1415                 stripe_nr = stripe_nr / factor;
1416         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
1417                 if (rw == WRITE)
1418                         multi->num_stripes = map->num_stripes;
1419                 else if (mirror_num)
1420                         stripe_index = mirror_num - 1;
1421         } else if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
1422                                 BTRFS_BLOCK_GROUP_RAID6)) {
1423
1424                 if (raid_map) {
1425                         int rot;
1426                         u64 tmp;
1427                         u64 raid56_full_stripe_start;
1428                         u64 full_stripe_len = nr_data_stripes(map) * map->stripe_len;
1429
1430                         /*
1431                          * align the start of our data stripe in the logical
1432                          * address space
1433                          */
1434                         raid56_full_stripe_start = offset / full_stripe_len;
1435                         raid56_full_stripe_start *= full_stripe_len;
1436
1437                         /* get the data stripe number */
1438                         stripe_nr = raid56_full_stripe_start / map->stripe_len;
1439                         stripe_nr = stripe_nr / nr_data_stripes(map);
1440
1441                         /* Work out the disk rotation on this stripe-set */
1442                         rot = stripe_nr % map->num_stripes;
1443
1444                         /* Fill in the logical address of each stripe */
1445                         tmp = stripe_nr * nr_data_stripes(map);
1446
1447                         for (i = 0; i < nr_data_stripes(map); i++)
1448                                 raid_map[(i+rot) % map->num_stripes] =
1449                                         ce->start + (tmp + i) * map->stripe_len;
1450
1451                         raid_map[(i+rot) % map->num_stripes] = BTRFS_RAID5_P_STRIPE;
1452                         if (map->type & BTRFS_BLOCK_GROUP_RAID6)
1453                                 raid_map[(i+rot+1) % map->num_stripes] = BTRFS_RAID6_Q_STRIPE;
1454
1455                         *length = map->stripe_len;
1456                         stripe_index = 0;
1457                         stripe_offset = 0;
1458                         multi->num_stripes = map->num_stripes;
1459                 } else {
1460                         stripe_index = stripe_nr % nr_data_stripes(map);
1461                         stripe_nr = stripe_nr / nr_data_stripes(map);
1462
1463                         /*
1464                          * Mirror #0 or #1 means the original data block.
1465                          * Mirror #2 is RAID5 parity block.
1466                          * Mirror #3 is RAID6 Q block.
1467                          */
1468                         if (mirror_num > 1)
1469                                 stripe_index = nr_data_stripes(map) + mirror_num - 2;
1470
1471                         /* We distribute the parity blocks across stripes */
1472                         stripe_index = (stripe_nr + stripe_index) % map->num_stripes;
1473                 }
1474         } else {
1475                 /*
1476                  * after this do_div call, stripe_nr is the number of stripes
1477                  * on this device we have to walk to find the data, and
1478                  * stripe_index is the number of our device in the stripe array
1479                  */
1480                 stripe_index = stripe_nr % map->num_stripes;
1481                 stripe_nr = stripe_nr / map->num_stripes;
1482         }
1483         BUG_ON(stripe_index >= map->num_stripes);
1484
1485         for (i = 0; i < multi->num_stripes; i++) {
1486                 multi->stripes[i].physical =
1487                         map->stripes[stripe_index].physical + stripe_offset +
1488                         stripe_nr * map->stripe_len;
1489                 multi->stripes[i].dev = map->stripes[stripe_index].dev;
1490                 stripe_index++;
1491         }
1492         *multi_ret = multi;
1493
1494         if (type)
1495                 *type = map->type;
1496
1497         if (raid_map) {
1498                 sort_parity_stripes(multi, raid_map);
1499                 *raid_map_ret = raid_map;
1500         }
1501 out:
1502         return 0;
1503 }
1504
1505 struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
1506                                        u8 *uuid, u8 *fsid)
1507 {
1508         struct btrfs_device *device;
1509         struct btrfs_fs_devices *cur_devices;
1510
1511         cur_devices = root->fs_info->fs_devices;
1512         while (cur_devices) {
1513                 if (!fsid ||
1514                     (!memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE) ||
1515                      root->fs_info->ignore_fsid_mismatch)) {
1516                         device = __find_device(&cur_devices->devices,
1517                                                devid, uuid);
1518                         if (device)
1519                                 return device;
1520                 }
1521                 cur_devices = cur_devices->seed;
1522         }
1523         return NULL;
1524 }
1525
1526 struct btrfs_device *
1527 btrfs_find_device_by_devid(struct btrfs_fs_devices *fs_devices,
1528                            u64 devid, int instance)
1529 {
1530         struct list_head *head = &fs_devices->devices;
1531         struct btrfs_device *dev;
1532         int num_found = 0;
1533
1534         list_for_each_entry(dev, head, dev_list) {
1535                 if (dev->devid == devid && num_found++ == instance)
1536                         return dev;
1537         }
1538         return NULL;
1539 }
1540
1541 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
1542 {
1543         struct cache_extent *ce;
1544         struct map_lookup *map;
1545         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
1546         int readonly = 0;
1547         int i;
1548
1549         /*
1550          * During chunk recovering, we may fail to find block group's
1551          * corresponding chunk, we will rebuild it later
1552          */
1553         ce = search_cache_extent(&map_tree->cache_tree, chunk_offset);
1554         if (!root->fs_info->is_chunk_recover)
1555                 BUG_ON(!ce);
1556         else
1557                 return 0;
1558
1559         map = container_of(ce, struct map_lookup, ce);
1560         for (i = 0; i < map->num_stripes; i++) {
1561                 if (!map->stripes[i].dev->writeable) {
1562                         readonly = 1;
1563                         break;
1564                 }
1565         }
1566
1567         return readonly;
1568 }
1569
1570 static struct btrfs_device *fill_missing_device(u64 devid)
1571 {
1572         struct btrfs_device *device;
1573
1574         device = kzalloc(sizeof(*device), GFP_NOFS);
1575         device->devid = devid;
1576         device->fd = -1;
1577         return device;
1578 }
1579
1580 /*
1581  * Slot is used to verfy the chunk item is valid
1582  *
1583  * For sys chunk in superblock, pass -1 to indicate sys chunk.
1584  */
1585 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
1586                           struct extent_buffer *leaf,
1587                           struct btrfs_chunk *chunk, int slot)
1588 {
1589         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
1590         struct map_lookup *map;
1591         struct cache_extent *ce;
1592         u64 logical;
1593         u64 length;
1594         u64 devid;
1595         u8 uuid[BTRFS_UUID_SIZE];
1596         int num_stripes;
1597         int ret;
1598         int i;
1599
1600         logical = key->offset;
1601         length = btrfs_chunk_length(leaf, chunk);
1602
1603         ce = search_cache_extent(&map_tree->cache_tree, logical);
1604
1605         /* already mapped? */
1606         if (ce && ce->start <= logical && ce->start + ce->size > logical) {
1607                 return 0;
1608         }
1609
1610         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
1611         map = kmalloc(btrfs_map_lookup_size(num_stripes), GFP_NOFS);
1612         if (!map)
1613                 return -ENOMEM;
1614
1615         map->ce.start = logical;
1616         map->ce.size = length;
1617         map->num_stripes = num_stripes;
1618         map->io_width = btrfs_chunk_io_width(leaf, chunk);
1619         map->io_align = btrfs_chunk_io_align(leaf, chunk);
1620         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
1621         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
1622         map->type = btrfs_chunk_type(leaf, chunk);
1623         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
1624
1625         /* Check on chunk item type */
1626         if (map->type & ~(BTRFS_BLOCK_GROUP_TYPE_MASK |
1627                           BTRFS_BLOCK_GROUP_PROFILE_MASK)) {
1628                 fprintf(stderr, "Unknown chunk type bits: %llu\n",
1629                         map->type & ~(BTRFS_BLOCK_GROUP_TYPE_MASK |
1630                                       BTRFS_BLOCK_GROUP_PROFILE_MASK));
1631                 ret = -EIO;
1632                 goto out;
1633         }
1634
1635         /*
1636          * Btrfs_chunk contains at least one stripe, and for sys_chunk
1637          * it can't exceed the system chunk array size
1638          * For normal chunk, it should match its chunk item size.
1639          */
1640         if (num_stripes < 1 ||
1641             (slot == -1 && sizeof(struct btrfs_stripe) * num_stripes >
1642              BTRFS_SYSTEM_CHUNK_ARRAY_SIZE) ||
1643             (slot >= 0 && sizeof(struct btrfs_stripe) * (num_stripes - 1) >
1644              btrfs_item_size_nr(leaf, slot))) {
1645                 fprintf(stderr, "Invalid num_stripes: %u\n",
1646                         num_stripes);
1647                 ret = -EIO;
1648                 goto out;
1649         }
1650
1651         /*
1652          * Device number check against profile
1653          */
1654         if ((map->type & BTRFS_BLOCK_GROUP_RAID10 && map->sub_stripes == 0) ||
1655             (map->type & BTRFS_BLOCK_GROUP_RAID1 && num_stripes < 1) ||
1656             (map->type & BTRFS_BLOCK_GROUP_RAID5 && num_stripes < 2) ||
1657             (map->type & BTRFS_BLOCK_GROUP_RAID6 && num_stripes < 3) ||
1658             (map->type & BTRFS_BLOCK_GROUP_DUP && num_stripes > 2) ||
1659             ((map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0 &&
1660              num_stripes != 1)) {
1661                 fprintf(stderr,
1662                         "Invalid num_stripes:sub_stripes %u:%u for profile %llu\n",
1663                         num_stripes, map->sub_stripes,
1664                         map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK);
1665                 ret = -EIO;
1666                 goto out;
1667         }
1668
1669         for (i = 0; i < num_stripes; i++) {
1670                 map->stripes[i].physical =
1671                         btrfs_stripe_offset_nr(leaf, chunk, i);
1672                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
1673                 read_extent_buffer(leaf, uuid, (unsigned long)
1674                                    btrfs_stripe_dev_uuid_nr(chunk, i),
1675                                    BTRFS_UUID_SIZE);
1676                 map->stripes[i].dev = btrfs_find_device(root, devid, uuid,
1677                                                         NULL);
1678                 if (!map->stripes[i].dev) {
1679                         map->stripes[i].dev = fill_missing_device(devid);
1680                         printf("warning, device %llu is missing\n",
1681                                (unsigned long long)devid);
1682                 }
1683
1684         }
1685         ret = insert_cache_extent(&map_tree->cache_tree, &map->ce);
1686         BUG_ON(ret);
1687
1688         return 0;
1689 out:
1690         free(map);
1691         return ret;
1692 }
1693
1694 static int fill_device_from_item(struct extent_buffer *leaf,
1695                                  struct btrfs_dev_item *dev_item,
1696                                  struct btrfs_device *device)
1697 {
1698         unsigned long ptr;
1699
1700         device->devid = btrfs_device_id(leaf, dev_item);
1701         device->total_bytes = btrfs_device_total_bytes(leaf, dev_item);
1702         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
1703         device->type = btrfs_device_type(leaf, dev_item);
1704         device->io_align = btrfs_device_io_align(leaf, dev_item);
1705         device->io_width = btrfs_device_io_width(leaf, dev_item);
1706         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
1707
1708         ptr = (unsigned long)btrfs_device_uuid(dev_item);
1709         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1710
1711         return 0;
1712 }
1713
1714 static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
1715 {
1716         struct btrfs_fs_devices *fs_devices;
1717         int ret;
1718
1719         fs_devices = root->fs_info->fs_devices->seed;
1720         while (fs_devices) {
1721                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
1722                         ret = 0;
1723                         goto out;
1724                 }
1725                 fs_devices = fs_devices->seed;
1726         }
1727
1728         fs_devices = find_fsid(fsid);
1729         if (!fs_devices) {
1730                 /* missing all seed devices */
1731                 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
1732                 if (!fs_devices) {
1733                         ret = -ENOMEM;
1734                         goto out;
1735                 }
1736                 INIT_LIST_HEAD(&fs_devices->devices);
1737                 list_add(&fs_devices->list, &fs_uuids);
1738                 memcpy(fs_devices->fsid, fsid, BTRFS_FSID_SIZE);
1739         }
1740
1741         ret = btrfs_open_devices(fs_devices, O_RDONLY);
1742         if (ret)
1743                 goto out;
1744
1745         fs_devices->seed = root->fs_info->fs_devices->seed;
1746         root->fs_info->fs_devices->seed = fs_devices;
1747 out:
1748         return ret;
1749 }
1750
1751 static int read_one_dev(struct btrfs_root *root,
1752                         struct extent_buffer *leaf,
1753                         struct btrfs_dev_item *dev_item)
1754 {
1755         struct btrfs_device *device;
1756         u64 devid;
1757         int ret = 0;
1758         u8 fs_uuid[BTRFS_UUID_SIZE];
1759         u8 dev_uuid[BTRFS_UUID_SIZE];
1760
1761         devid = btrfs_device_id(leaf, dev_item);
1762         read_extent_buffer(leaf, dev_uuid,
1763                            (unsigned long)btrfs_device_uuid(dev_item),
1764                            BTRFS_UUID_SIZE);
1765         read_extent_buffer(leaf, fs_uuid,
1766                            (unsigned long)btrfs_device_fsid(dev_item),
1767                            BTRFS_UUID_SIZE);
1768
1769         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
1770                 ret = open_seed_devices(root, fs_uuid);
1771                 if (ret)
1772                         return ret;
1773         }
1774
1775         device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
1776         if (!device) {
1777                 printk("warning devid %llu not found already\n",
1778                         (unsigned long long)devid);
1779                 device = kzalloc(sizeof(*device), GFP_NOFS);
1780                 if (!device)
1781                         return -ENOMEM;
1782                 device->fd = -1;
1783                 list_add(&device->dev_list,
1784                          &root->fs_info->fs_devices->devices);
1785         }
1786
1787         fill_device_from_item(leaf, dev_item, device);
1788         device->dev_root = root->fs_info->dev_root;
1789         return ret;
1790 }
1791
1792 int btrfs_read_sys_array(struct btrfs_root *root)
1793 {
1794         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
1795         struct extent_buffer *sb;
1796         struct btrfs_disk_key *disk_key;
1797         struct btrfs_chunk *chunk;
1798         u8 *array_ptr;
1799         unsigned long sb_array_offset;
1800         int ret = 0;
1801         u32 num_stripes;
1802         u32 array_size;
1803         u32 len = 0;
1804         u32 cur_offset;
1805         struct btrfs_key key;
1806
1807         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
1808                                           BTRFS_SUPER_INFO_SIZE);
1809         if (!sb)
1810                 return -ENOMEM;
1811         btrfs_set_buffer_uptodate(sb);
1812         write_extent_buffer(sb, super_copy, 0, sizeof(*super_copy));
1813         array_size = btrfs_super_sys_array_size(super_copy);
1814
1815         array_ptr = super_copy->sys_chunk_array;
1816         sb_array_offset = offsetof(struct btrfs_super_block, sys_chunk_array);
1817         cur_offset = 0;
1818
1819         while (cur_offset < array_size) {
1820                 disk_key = (struct btrfs_disk_key *)array_ptr;
1821                 len = sizeof(*disk_key);
1822                 if (cur_offset + len > array_size)
1823                         goto out_short_read;
1824
1825                 btrfs_disk_key_to_cpu(&key, disk_key);
1826
1827                 array_ptr += len;
1828                 sb_array_offset += len;
1829                 cur_offset += len;
1830
1831                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
1832                         chunk = (struct btrfs_chunk *)sb_array_offset;
1833                         /*
1834                          * At least one btrfs_chunk with one stripe must be
1835                          * present, exact stripe count check comes afterwards
1836                          */
1837                         len = btrfs_chunk_item_size(1);
1838                         if (cur_offset + len > array_size)
1839                                 goto out_short_read;
1840
1841                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
1842                         if (!num_stripes) {
1843                                 printk(
1844             "ERROR: invalid number of stripes %u in sys_array at offset %u\n",
1845                                         num_stripes, cur_offset);
1846                                 ret = -EIO;
1847                                 break;
1848                         }
1849
1850                         len = btrfs_chunk_item_size(num_stripes);
1851                         if (cur_offset + len > array_size)
1852                                 goto out_short_read;
1853
1854                         ret = read_one_chunk(root, &key, sb, chunk, -1);
1855                         if (ret)
1856                                 break;
1857                 } else {
1858                         BUG();
1859                 }
1860                 array_ptr += len;
1861                 sb_array_offset += len;
1862                 cur_offset += len;
1863         }
1864         free_extent_buffer(sb);
1865         return ret;
1866
1867 out_short_read:
1868         printk("ERROR: sys_array too short to read %u bytes at offset %u\n",
1869                         len, cur_offset);
1870         free_extent_buffer(sb);
1871         return -EIO;
1872 }
1873
1874 int btrfs_read_chunk_tree(struct btrfs_root *root)
1875 {
1876         struct btrfs_path *path;
1877         struct extent_buffer *leaf;
1878         struct btrfs_key key;
1879         struct btrfs_key found_key;
1880         int ret;
1881         int slot;
1882
1883         root = root->fs_info->chunk_root;
1884
1885         path = btrfs_alloc_path();
1886         if (!path)
1887                 return -ENOMEM;
1888
1889         /*
1890          * Read all device items, and then all the chunk items. All
1891          * device items are found before any chunk item (their object id
1892          * is smaller than the lowest possible object id for a chunk
1893          * item - BTRFS_FIRST_CHUNK_TREE_OBJECTID).
1894          */
1895         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1896         key.offset = 0;
1897         key.type = 0;
1898         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1899         if (ret < 0)
1900                 goto error;
1901         while(1) {
1902                 leaf = path->nodes[0];
1903                 slot = path->slots[0];
1904                 if (slot >= btrfs_header_nritems(leaf)) {
1905                         ret = btrfs_next_leaf(root, path);
1906                         if (ret == 0)
1907                                 continue;
1908                         if (ret < 0)
1909                                 goto error;
1910                         break;
1911                 }
1912                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
1913                 if (found_key.type == BTRFS_DEV_ITEM_KEY) {
1914                         struct btrfs_dev_item *dev_item;
1915                         dev_item = btrfs_item_ptr(leaf, slot,
1916                                                   struct btrfs_dev_item);
1917                         ret = read_one_dev(root, leaf, dev_item);
1918                         BUG_ON(ret);
1919                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
1920                         struct btrfs_chunk *chunk;
1921                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
1922                         ret = read_one_chunk(root, &found_key, leaf, chunk,
1923                                              slot);
1924                         BUG_ON(ret);
1925                 }
1926                 path->slots[0]++;
1927         }
1928
1929         ret = 0;
1930 error:
1931         btrfs_free_path(path);
1932         return ret;
1933 }
1934
1935 struct list_head *btrfs_scanned_uuids(void)
1936 {
1937         return &fs_uuids;
1938 }
1939
1940 static int rmw_eb(struct btrfs_fs_info *info,
1941                   struct extent_buffer *eb, struct extent_buffer *orig_eb)
1942 {
1943         int ret;
1944         unsigned long orig_off = 0;
1945         unsigned long dest_off = 0;
1946         unsigned long copy_len = eb->len;
1947
1948         ret = read_whole_eb(info, eb, 0);
1949         if (ret)
1950                 return ret;
1951
1952         if (eb->start + eb->len <= orig_eb->start ||
1953             eb->start >= orig_eb->start + orig_eb->len)
1954                 return 0;
1955         /*
1956          * | ----- orig_eb ------- |
1957          *         | ----- stripe -------  |
1958          *         | ----- orig_eb ------- |
1959          *              | ----- orig_eb ------- |
1960          */
1961         if (eb->start > orig_eb->start)
1962                 orig_off = eb->start - orig_eb->start;
1963         if (orig_eb->start > eb->start)
1964                 dest_off = orig_eb->start - eb->start;
1965
1966         if (copy_len > orig_eb->len - orig_off)
1967                 copy_len = orig_eb->len - orig_off;
1968         if (copy_len > eb->len - dest_off)
1969                 copy_len = eb->len - dest_off;
1970
1971         memcpy(eb->data + dest_off, orig_eb->data + orig_off, copy_len);
1972         return 0;
1973 }
1974
1975 static void split_eb_for_raid56(struct btrfs_fs_info *info,
1976                                 struct extent_buffer *orig_eb,
1977                                struct extent_buffer **ebs,
1978                                u64 stripe_len, u64 *raid_map,
1979                                int num_stripes)
1980 {
1981         struct extent_buffer *eb;
1982         u64 start = orig_eb->start;
1983         u64 this_eb_start;
1984         int i;
1985         int ret;
1986
1987         for (i = 0; i < num_stripes; i++) {
1988                 if (raid_map[i] >= BTRFS_RAID5_P_STRIPE)
1989                         break;
1990
1991                 eb = calloc(1, sizeof(struct extent_buffer) + stripe_len);
1992                 if (!eb)
1993                         BUG();
1994
1995                 eb->start = raid_map[i];
1996                 eb->len = stripe_len;
1997                 eb->refs = 1;
1998                 eb->flags = 0;
1999                 eb->fd = -1;
2000                 eb->dev_bytenr = (u64)-1;
2001
2002                 this_eb_start = raid_map[i];
2003
2004                 if (start > this_eb_start ||
2005                     start + orig_eb->len < this_eb_start + stripe_len) {
2006                         ret = rmw_eb(info, eb, orig_eb);
2007                         BUG_ON(ret);
2008                 } else {
2009                         memcpy(eb->data, orig_eb->data + eb->start - start, stripe_len);
2010                 }
2011                 ebs[i] = eb;
2012         }
2013 }
2014
2015 int write_raid56_with_parity(struct btrfs_fs_info *info,
2016                              struct extent_buffer *eb,
2017                              struct btrfs_multi_bio *multi,
2018                              u64 stripe_len, u64 *raid_map)
2019 {
2020         struct extent_buffer **ebs, *p_eb = NULL, *q_eb = NULL;
2021         int i;
2022         int j;
2023         int ret;
2024         int alloc_size = eb->len;
2025
2026         ebs = kmalloc(sizeof(*ebs) * multi->num_stripes, GFP_NOFS);
2027         BUG_ON(!ebs);
2028
2029         if (stripe_len > alloc_size)
2030                 alloc_size = stripe_len;
2031
2032         split_eb_for_raid56(info, eb, ebs, stripe_len, raid_map,
2033                             multi->num_stripes);
2034
2035         for (i = 0; i < multi->num_stripes; i++) {
2036                 struct extent_buffer *new_eb;
2037                 if (raid_map[i] < BTRFS_RAID5_P_STRIPE) {
2038                         ebs[i]->dev_bytenr = multi->stripes[i].physical;
2039                         ebs[i]->fd = multi->stripes[i].dev->fd;
2040                         multi->stripes[i].dev->total_ios++;
2041                         BUG_ON(ebs[i]->start != raid_map[i]);
2042                         continue;
2043                 }
2044                 new_eb = kmalloc(sizeof(*eb) + alloc_size, GFP_NOFS);
2045                 BUG_ON(!new_eb);
2046                 new_eb->dev_bytenr = multi->stripes[i].physical;
2047                 new_eb->fd = multi->stripes[i].dev->fd;
2048                 multi->stripes[i].dev->total_ios++;
2049                 new_eb->len = stripe_len;
2050
2051                 if (raid_map[i] == BTRFS_RAID5_P_STRIPE)
2052                         p_eb = new_eb;
2053                 else if (raid_map[i] == BTRFS_RAID6_Q_STRIPE)
2054                         q_eb = new_eb;
2055         }
2056         if (q_eb) {
2057                 void **pointers;
2058
2059                 pointers = kmalloc(sizeof(*pointers) * multi->num_stripes,
2060                                    GFP_NOFS);
2061                 BUG_ON(!pointers);
2062
2063                 ebs[multi->num_stripes - 2] = p_eb;
2064                 ebs[multi->num_stripes - 1] = q_eb;
2065
2066                 for (i = 0; i < multi->num_stripes; i++)
2067                         pointers[i] = ebs[i]->data;
2068
2069                 raid6_gen_syndrome(multi->num_stripes, stripe_len, pointers);
2070                 kfree(pointers);
2071         } else {
2072                 ebs[multi->num_stripes - 1] = p_eb;
2073                 memcpy(p_eb->data, ebs[0]->data, stripe_len);
2074                 for (j = 1; j < multi->num_stripes - 1; j++) {
2075                         for (i = 0; i < stripe_len; i += sizeof(unsigned long)) {
2076                                 *(unsigned long *)(p_eb->data + i) ^=
2077                                         *(unsigned long *)(ebs[j]->data + i);
2078                         }
2079                 }
2080         }
2081
2082         for (i = 0; i < multi->num_stripes; i++) {
2083                 ret = write_extent_to_disk(ebs[i]);
2084                 BUG_ON(ret);
2085                 if (ebs[i] != eb)
2086                         kfree(ebs[i]);
2087         }
2088
2089         kfree(ebs);
2090
2091         return 0;
2092 }