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btrfs-progs: fix wrong data ratio for raid56 in btrfs-file-usage
[btrfs-progs-unstable/devel.git] / volumes.c
blob5b007fc8975ad39237f1022af214ebc513ad2893
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 #define _XOPEN_SOURCE 600
19 #define __USE_XOPEN2K
20 #include <stdio.h>
21 #include <stdlib.h>
22 #include <sys/types.h>
23 #include <sys/stat.h>
24 #include <uuid/uuid.h>
25 #include <fcntl.h>
26 #include <unistd.h>
27 #include "ctree.h"
28 #include "disk-io.h"
29 #include "transaction.h"
30 #include "print-tree.h"
31 #include "volumes.h"
32 #include "math.h"
33
34 struct stripe {
35 struct btrfs_device *dev;
36 u64 physical;
37 };
38
39 static inline int nr_parity_stripes(struct map_lookup *map)
40 {
41 if (map->type & BTRFS_BLOCK_GROUP_RAID5)
42 return 1;
43 else if (map->type & BTRFS_BLOCK_GROUP_RAID6)
44 return 2;
45 else
46 return 0;
47 }
48
49 static inline int nr_data_stripes(struct map_lookup *map)
50 {
51 return map->num_stripes - nr_parity_stripes(map);
52 }
53
54 #define is_parity_stripe(x) ( ((x) == BTRFS_RAID5_P_STRIPE) || ((x) == BTRFS_RAID6_Q_STRIPE) )
55
56 static LIST_HEAD(fs_uuids);
57
58 static struct btrfs_device *__find_device(struct list_head *head, u64 devid,
59 u8 *uuid)
60 {
61 struct btrfs_device *dev;
62 struct list_head *cur;
63
64 list_for_each(cur, head) {
65 dev = list_entry(cur, struct btrfs_device, dev_list);
66 if (dev->devid == devid &&
67 !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE)) {
68 return dev;
69 }
70 }
71 return NULL;
72 }
73
74 static struct btrfs_fs_devices *find_fsid(u8 *fsid)
75 {
76 struct list_head *cur;
77 struct btrfs_fs_devices *fs_devices;
78
79 list_for_each(cur, &fs_uuids) {
80 fs_devices = list_entry(cur, struct btrfs_fs_devices, list);
81 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
82 return fs_devices;
83 }
84 return NULL;
85 }
86
87 static int device_list_add(const char *path,
88 struct btrfs_super_block *disk_super,
89 u64 devid, struct btrfs_fs_devices **fs_devices_ret)
90 {
91 struct btrfs_device *device;
92 struct btrfs_fs_devices *fs_devices;
93 u64 found_transid = btrfs_super_generation(disk_super);
94
95 fs_devices = find_fsid(disk_super->fsid);
96 if (!fs_devices) {
97 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
98 if (!fs_devices)
99 return -ENOMEM;
100 INIT_LIST_HEAD(&fs_devices->devices);
101 list_add(&fs_devices->list, &fs_uuids);
102 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
103 fs_devices->latest_devid = devid;
104 fs_devices->latest_trans = found_transid;
105 fs_devices->lowest_devid = (u64)-1;
106 device = NULL;
107 } else {
108 device = __find_device(&fs_devices->devices, devid,
109 disk_super->dev_item.uuid);
110 }
111 if (!device) {
112 device = kzalloc(sizeof(*device), GFP_NOFS);
113 if (!device) {
114 /* we can safely leave the fs_devices entry around */
115 return -ENOMEM;
116 }
117 device->fd = -1;
118 device->devid = devid;
119 device->generation = found_transid;
120 memcpy(device->uuid, disk_super->dev_item.uuid,
121 BTRFS_UUID_SIZE);
122 device->name = kstrdup(path, GFP_NOFS);
123 if (!device->name) {
124 kfree(device);
125 return -ENOMEM;
126 }
127 device->label = kstrdup(disk_super->label, GFP_NOFS);
128 if (!device->label) {
129 kfree(device->name);
130 kfree(device);
131 return -ENOMEM;
132 }
133 device->total_devs = btrfs_super_num_devices(disk_super);
134 device->super_bytes_used = btrfs_super_bytes_used(disk_super);
135 device->total_bytes =
136 btrfs_stack_device_total_bytes(&disk_super->dev_item);
137 device->bytes_used =
138 btrfs_stack_device_bytes_used(&disk_super->dev_item);
139 list_add(&device->dev_list, &fs_devices->devices);
140 device->fs_devices = fs_devices;
141 } else if (!device->name || strcmp(device->name, path)) {
142 char *name = strdup(path);
143 if (!name)
144 return -ENOMEM;
145 kfree(device->name);
146 device->name = name;
147 }
148
149
150 if (found_transid > fs_devices->latest_trans) {
151 fs_devices->latest_devid = devid;
152 fs_devices->latest_trans = found_transid;
153 }
154 if (fs_devices->lowest_devid > devid) {
155 fs_devices->lowest_devid = devid;
156 }
157 *fs_devices_ret = fs_devices;
158 return 0;
159 }
160
161 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
162 {
163 struct btrfs_fs_devices *seed_devices;
164 struct btrfs_device *device;
165
166 again:
167 while (!list_empty(&fs_devices->devices)) {
168 device = list_entry(fs_devices->devices.next,
169 struct btrfs_device, dev_list);
170 if (device->fd != -1) {
171 fsync(device->fd);
172 if (posix_fadvise(device->fd, 0, 0, POSIX_FADV_DONTNEED))
173 fprintf(stderr, "Warning, could not drop caches\n");
174 close(device->fd);
175 device->fd = -1;
176 }
177 device->writeable = 0;
178 list_del(&device->dev_list);
179 /* free the memory */
180 free(device->name);
181 free(device->label);
182 free(device);
183 }
184
185 seed_devices = fs_devices->seed;
186 fs_devices->seed = NULL;
187 if (seed_devices) {
188 struct btrfs_fs_devices *orig;
189
190 orig = fs_devices;
191 fs_devices = seed_devices;
192 list_del(&orig->list);
193 free(orig);
194 goto again;
195 } else {
196 list_del(&fs_devices->list);
197 free(fs_devices);
198 }
199
200 return 0;
201 }
202
203 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, int flags)
204 {
205 int fd;
206 struct list_head *head = &fs_devices->devices;
207 struct list_head *cur;
208 struct btrfs_device *device;
209 int ret;
210
211 list_for_each(cur, head) {
212 device = list_entry(cur, struct btrfs_device, dev_list);
213 if (!device->name) {
214 printk("no name for device %llu, skip it now\n", device->devid);
215 continue;
216 }
217
218 fd = open(device->name, flags);
219 if (fd < 0) {
220 ret = -errno;
221 goto fail;
222 }
223
224 if (posix_fadvise(fd, 0, 0, POSIX_FADV_DONTNEED))
225 fprintf(stderr, "Warning, could not drop caches\n");
226
227 if (device->devid == fs_devices->latest_devid)
228 fs_devices->latest_bdev = fd;
229 if (device->devid == fs_devices->lowest_devid)
230 fs_devices->lowest_bdev = fd;
231 device->fd = fd;
232 if (flags & O_RDWR)
233 device->writeable = 1;
234 }
235 return 0;
236 fail:
237 btrfs_close_devices(fs_devices);
238 return ret;
239 }
240
241 int btrfs_scan_one_device(int fd, const char *path,
242 struct btrfs_fs_devices **fs_devices_ret,
243 u64 *total_devs, u64 super_offset, int super_recover)
244 {
245 struct btrfs_super_block *disk_super;
246 char *buf;
247 int ret;
248 u64 devid;
249
250 buf = malloc(4096);
251 if (!buf) {
252 ret = -ENOMEM;
253 goto error;
254 }
255 disk_super = (struct btrfs_super_block *)buf;
256 ret = btrfs_read_dev_super(fd, disk_super, super_offset, super_recover);
257 if (ret < 0) {
258 ret = -EIO;
259 goto error_brelse;
260 }
261 devid = btrfs_stack_device_id(&disk_super->dev_item);
262 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_METADUMP)
263 *total_devs = 1;
264 else
265 *total_devs = btrfs_super_num_devices(disk_super);
266
267 ret = device_list_add(path, disk_super, devid, fs_devices_ret);
268
269 error_brelse:
270 free(buf);
271 error:
272 return ret;
273 }
274
275 /*
276 * this uses a pretty simple search, the expectation is that it is
277 * called very infrequently and that a given device has a small number
278 * of extents
279 */
280 static int find_free_dev_extent(struct btrfs_trans_handle *trans,
281 struct btrfs_device *device,
282 struct btrfs_path *path,
283 u64 num_bytes, u64 *start)
284 {
285 struct btrfs_key key;
286 struct btrfs_root *root = device->dev_root;
287 struct btrfs_dev_extent *dev_extent = NULL;
288 u64 hole_size = 0;
289 u64 last_byte = 0;
290 u64 search_start = root->fs_info->alloc_start;
291 u64 search_end = device->total_bytes;
292 int ret;
293 int slot = 0;
294 int start_found;
295 struct extent_buffer *l;
296
297 start_found = 0;
298 path->reada = 2;
299
300 /* FIXME use last free of some kind */
301
302 /* we don't want to overwrite the superblock on the drive,
303 * so we make sure to start at an offset of at least 1MB
304 */
305 search_start = max(BTRFS_BLOCK_RESERVED_1M_FOR_SUPER, search_start);
306
307 if (search_start >= search_end) {
308 ret = -ENOSPC;
309 goto error;
310 }
311
312 key.objectid = device->devid;
313 key.offset = search_start;
314 key.type = BTRFS_DEV_EXTENT_KEY;
315 ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
316 if (ret < 0)
317 goto error;
318 ret = btrfs_previous_item(root, path, 0, key.type);
319 if (ret < 0)
320 goto error;
321 l = path->nodes[0];
322 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
323 while (1) {
324 l = path->nodes[0];
325 slot = path->slots[0];
326 if (slot >= btrfs_header_nritems(l)) {
327 ret = btrfs_next_leaf(root, path);
328 if (ret == 0)
329 continue;
330 if (ret < 0)
331 goto error;
332 no_more_items:
333 if (!start_found) {
334 if (search_start >= search_end) {
335 ret = -ENOSPC;
336 goto error;
337 }
338 *start = search_start;
339 start_found = 1;
340 goto check_pending;
341 }
342 *start = last_byte > search_start ?
343 last_byte : search_start;
344 if (search_end <= *start) {
345 ret = -ENOSPC;
346 goto error;
347 }
348 goto check_pending;
349 }
350 btrfs_item_key_to_cpu(l, &key, slot);
351
352 if (key.objectid < device->devid)
353 goto next;
354
355 if (key.objectid > device->devid)
356 goto no_more_items;
357
358 if (key.offset >= search_start && key.offset > last_byte &&
359 start_found) {
360 if (last_byte < search_start)
361 last_byte = search_start;
362 hole_size = key.offset - last_byte;
363 if (key.offset > last_byte &&
364 hole_size >= num_bytes) {
365 *start = last_byte;
366 goto check_pending;
367 }
368 }
369 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY) {
370 goto next;
371 }
372
373 start_found = 1;
374 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
375 last_byte = key.offset + btrfs_dev_extent_length(l, dev_extent);
376 next:
377 path->slots[0]++;
378 cond_resched();
379 }
380 check_pending:
381 /* we have to make sure we didn't find an extent that has already
382 * been allocated by the map tree or the original allocation
383 */
384 btrfs_release_path(path);
385 BUG_ON(*start < search_start);
386
387 if (*start + num_bytes > search_end) {
388 ret = -ENOSPC;
389 goto error;
390 }
391 /* check for pending inserts here */
392 return 0;
393
394 error:
395 btrfs_release_path(path);
396 return ret;
397 }
398
399 static int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
400 struct btrfs_device *device,
401 u64 chunk_tree, u64 chunk_objectid,
402 u64 chunk_offset,
403 u64 num_bytes, u64 *start)
404 {
405 int ret;
406 struct btrfs_path *path;
407 struct btrfs_root *root = device->dev_root;
408 struct btrfs_dev_extent *extent;
409 struct extent_buffer *leaf;
410 struct btrfs_key key;
411
412 path = btrfs_alloc_path();
413 if (!path)
414 return -ENOMEM;
415
416 ret = find_free_dev_extent(trans, device, path, num_bytes, start);
417 if (ret) {
418 goto err;
419 }
420
421 key.objectid = device->devid;
422 key.offset = *start;
423 key.type = BTRFS_DEV_EXTENT_KEY;
424 ret = btrfs_insert_empty_item(trans, root, path, &key,
425 sizeof(*extent));
426 BUG_ON(ret);
427
428 leaf = path->nodes[0];
429 extent = btrfs_item_ptr(leaf, path->slots[0],
430 struct btrfs_dev_extent);
431 btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
432 btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
433 btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
434
435 write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
436 (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
437 BTRFS_UUID_SIZE);
438
439 btrfs_set_dev_extent_length(leaf, extent, num_bytes);
440 btrfs_mark_buffer_dirty(leaf);
441 err:
442 btrfs_free_path(path);
443 return ret;
444 }
445
446 static int find_next_chunk(struct btrfs_root *root, u64 objectid, u64 *offset)
447 {
448 struct btrfs_path *path;
449 int ret;
450 struct btrfs_key key;
451 struct btrfs_chunk *chunk;
452 struct btrfs_key found_key;
453
454 path = btrfs_alloc_path();
455 BUG_ON(!path);
456
457 key.objectid = objectid;
458 key.offset = (u64)-1;
459 key.type = BTRFS_CHUNK_ITEM_KEY;
460
461 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
462 if (ret < 0)
463 goto error;
464
465 BUG_ON(ret == 0);
466
467 ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
468 if (ret) {
469 *offset = 0;
470 } else {
471 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
472 path->slots[0]);
473 if (found_key.objectid != objectid)
474 *offset = 0;
475 else {
476 chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
477 struct btrfs_chunk);
478 *offset = found_key.offset +
479 btrfs_chunk_length(path->nodes[0], chunk);
480 }
481 }
482 ret = 0;
483 error:
484 btrfs_free_path(path);
485 return ret;
486 }
487
488 static int find_next_devid(struct btrfs_root *root, struct btrfs_path *path,
489 u64 *objectid)
490 {
491 int ret;
492 struct btrfs_key key;
493 struct btrfs_key found_key;
494
495 key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
496 key.type = BTRFS_DEV_ITEM_KEY;
497 key.offset = (u64)-1;
498
499 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
500 if (ret < 0)
501 goto error;
502
503 BUG_ON(ret == 0);
504
505 ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
506 BTRFS_DEV_ITEM_KEY);
507 if (ret) {
508 *objectid = 1;
509 } else {
510 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
511 path->slots[0]);
512 *objectid = found_key.offset + 1;
513 }
514 ret = 0;
515 error:
516 btrfs_release_path(path);
517 return ret;
518 }
519
520 /*
521 * the device information is stored in the chunk root
522 * the btrfs_device struct should be fully filled in
523 */
524 int btrfs_add_device(struct btrfs_trans_handle *trans,
525 struct btrfs_root *root,
526 struct btrfs_device *device)
527 {
528 int ret;
529 struct btrfs_path *path;
530 struct btrfs_dev_item *dev_item;
531 struct extent_buffer *leaf;
532 struct btrfs_key key;
533 unsigned long ptr;
534 u64 free_devid = 0;
535
536 root = root->fs_info->chunk_root;
537
538 path = btrfs_alloc_path();
539 if (!path)
540 return -ENOMEM;
541
542 ret = find_next_devid(root, path, &free_devid);
543 if (ret)
544 goto out;
545
546 key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
547 key.type = BTRFS_DEV_ITEM_KEY;
548 key.offset = free_devid;
549
550 ret = btrfs_insert_empty_item(trans, root, path, &key,
551 sizeof(*dev_item));
552 if (ret)
553 goto out;
554
555 leaf = path->nodes[0];
556 dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
557
558 device->devid = free_devid;
559 btrfs_set_device_id(leaf, dev_item, device->devid);
560 btrfs_set_device_generation(leaf, dev_item, 0);
561 btrfs_set_device_type(leaf, dev_item, device->type);
562 btrfs_set_device_io_align(leaf, dev_item, device->io_align);
563 btrfs_set_device_io_width(leaf, dev_item, device->io_width);
564 btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
565 btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
566 btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
567 btrfs_set_device_group(leaf, dev_item, 0);
568 btrfs_set_device_seek_speed(leaf, dev_item, 0);
569 btrfs_set_device_bandwidth(leaf, dev_item, 0);
570 btrfs_set_device_start_offset(leaf, dev_item, 0);
571
572 ptr = (unsigned long)btrfs_device_uuid(dev_item);
573 write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
574 ptr = (unsigned long)btrfs_device_fsid(dev_item);
575 write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
576 btrfs_mark_buffer_dirty(leaf);
577 ret = 0;
578
579 out:
580 btrfs_free_path(path);
581 return ret;
582 }
583
584 int btrfs_update_device(struct btrfs_trans_handle *trans,
585 struct btrfs_device *device)
586 {
587 int ret;
588 struct btrfs_path *path;
589 struct btrfs_root *root;
590 struct btrfs_dev_item *dev_item;
591 struct extent_buffer *leaf;
592 struct btrfs_key key;
593
594 root = device->dev_root->fs_info->chunk_root;
595
596 path = btrfs_alloc_path();
597 if (!path)
598 return -ENOMEM;
599
600 key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
601 key.type = BTRFS_DEV_ITEM_KEY;
602 key.offset = device->devid;
603
604 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
605 if (ret < 0)
606 goto out;
607
608 if (ret > 0) {
609 ret = -ENOENT;
610 goto out;
611 }
612
613 leaf = path->nodes[0];
614 dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
615
616 btrfs_set_device_id(leaf, dev_item, device->devid);
617 btrfs_set_device_type(leaf, dev_item, device->type);
618 btrfs_set_device_io_align(leaf, dev_item, device->io_align);
619 btrfs_set_device_io_width(leaf, dev_item, device->io_width);
620 btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
621 btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
622 btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
623 btrfs_mark_buffer_dirty(leaf);
624
625 out:
626 btrfs_free_path(path);
627 return ret;
628 }
629
630 int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
631 struct btrfs_root *root,
632 struct btrfs_key *key,
633 struct btrfs_chunk *chunk, int item_size)
634 {
635 struct btrfs_super_block *super_copy = root->fs_info->super_copy;
636 struct btrfs_disk_key disk_key;
637 u32 array_size;
638 u8 *ptr;
639
640 array_size = btrfs_super_sys_array_size(super_copy);
641 if (array_size + item_size + sizeof(disk_key)
642 > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
643 return -EFBIG;
644
645 ptr = super_copy->sys_chunk_array + array_size;
646 btrfs_cpu_key_to_disk(&disk_key, key);
647 memcpy(ptr, &disk_key, sizeof(disk_key));
648 ptr += sizeof(disk_key);
649 memcpy(ptr, chunk, item_size);
650 item_size += sizeof(disk_key);
651 btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
652 return 0;
653 }
654
655 static u64 chunk_bytes_by_type(u64 type, u64 calc_size, int num_stripes,
656 int sub_stripes)
657 {
658 if (type & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_DUP))
659 return calc_size;
660 else if (type & BTRFS_BLOCK_GROUP_RAID10)
661 return calc_size * (num_stripes / sub_stripes);
662 else if (type & BTRFS_BLOCK_GROUP_RAID5)
663 return calc_size * (num_stripes - 1);
664 else if (type & BTRFS_BLOCK_GROUP_RAID6)
665 return calc_size * (num_stripes - 2);
666 else
667 return calc_size * num_stripes;
668 }
669
670
671 static u32 find_raid56_stripe_len(u32 data_devices, u32 dev_stripe_target)
672 {
673 /* TODO, add a way to store the preferred stripe size */
674 return BTRFS_STRIPE_LEN;
675 }
676
677 /*
678 * btrfs_device_avail_bytes - count bytes available for alloc_chunk
679 *
680 * It is not equal to "device->total_bytes - device->bytes_used".
681 * We do not allocate any chunk in 1M at beginning of device, and not
682 * allowed to allocate any chunk before alloc_start if it is specified.
683 * So search holes from max(1M, alloc_start) to device->total_bytes.
684 */
685 static int btrfs_device_avail_bytes(struct btrfs_trans_handle *trans,
686 struct btrfs_device *device,
687 u64 *avail_bytes)
688 {
689 struct btrfs_path *path;
690 struct btrfs_root *root = device->dev_root;
691 struct btrfs_key key;
692 struct btrfs_dev_extent *dev_extent = NULL;
693 struct extent_buffer *l;
694 u64 search_start = root->fs_info->alloc_start;
695 u64 search_end = device->total_bytes;
696 u64 extent_end = 0;
697 u64 free_bytes = 0;
698 int ret;
699 int slot = 0;
700
701 search_start = max(BTRFS_BLOCK_RESERVED_1M_FOR_SUPER, search_start);
702
703 path = btrfs_alloc_path();
704 if (!path)
705 return -ENOMEM;
706
707 key.objectid = device->devid;
708 key.offset = root->fs_info->alloc_start;
709 key.type = BTRFS_DEV_EXTENT_KEY;
710
711 path->reada = 2;
712 ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
713 if (ret < 0)
714 goto error;
715 ret = btrfs_previous_item(root, path, 0, key.type);
716 if (ret < 0)
717 goto error;
718
719 while (1) {
720 l = path->nodes[0];
721 slot = path->slots[0];
722 if (slot >= btrfs_header_nritems(l)) {
723 ret = btrfs_next_leaf(root, path);
724 if (ret == 0)
725 continue;
726 if (ret < 0)
727 goto error;
728 break;
729 }
730 btrfs_item_key_to_cpu(l, &key, slot);
731
732 if (key.objectid < device->devid)
733 goto next;
734 if (key.objectid > device->devid)
735 break;
736 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
737 goto next;
738 if (key.offset > search_end)
739 break;
740 if (key.offset > search_start)
741 free_bytes += key.offset - search_start;
742
743 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
744 extent_end = key.offset + btrfs_dev_extent_length(l,
745 dev_extent);
746 if (extent_end > search_start)
747 search_start = extent_end;
748 if (search_start > search_end)
749 break;
750 next:
751 path->slots[0]++;
752 cond_resched();
753 }
754
755 if (search_start < search_end)
756 free_bytes += search_end - search_start;
757
758 *avail_bytes = free_bytes;
759 ret = 0;
760 error:
761 btrfs_free_path(path);
762 return ret;
763 }
764
765 #define BTRFS_MAX_DEVS(r) ((BTRFS_LEAF_DATA_SIZE(r) \
766 - sizeof(struct btrfs_item) \
767 - sizeof(struct btrfs_chunk)) \
768 / sizeof(struct btrfs_stripe) + 1)
769
770 #define BTRFS_MAX_DEVS_SYS_CHUNK ((BTRFS_SYSTEM_CHUNK_ARRAY_SIZE \
771 - 2 * sizeof(struct btrfs_disk_key) \
772 - 2 * sizeof(struct btrfs_chunk)) \
773 / sizeof(struct btrfs_stripe) + 1)
774
775 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
776 struct btrfs_root *extent_root, u64 *start,
777 u64 *num_bytes, u64 type)
778 {
779 u64 dev_offset;
780 struct btrfs_fs_info *info = extent_root->fs_info;
781 struct btrfs_root *chunk_root = info->chunk_root;
782 struct btrfs_stripe *stripes;
783 struct btrfs_device *device = NULL;
784 struct btrfs_chunk *chunk;
785 struct list_head private_devs;
786 struct list_head *dev_list = &info->fs_devices->devices;
787 struct list_head *cur;
788 struct map_lookup *map;
789 int min_stripe_size = 1 * 1024 * 1024;
790 u64 calc_size = 8 * 1024 * 1024;
791 u64 min_free;
792 u64 max_chunk_size = 4 * calc_size;
793 u64 avail = 0;
794 u64 max_avail = 0;
795 u64 percent_max;
796 int num_stripes = 1;
797 int max_stripes = 0;
798 int min_stripes = 1;
799 int sub_stripes = 0;
800 int looped = 0;
801 int ret;
802 int index;
803 int stripe_len = BTRFS_STRIPE_LEN;
804 struct btrfs_key key;
805 u64 offset;
806
807 if (list_empty(dev_list)) {
808 return -ENOSPC;
809 }
810
811 if (type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
812 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
813 BTRFS_BLOCK_GROUP_RAID10 |
814 BTRFS_BLOCK_GROUP_DUP)) {
815 if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
816 calc_size = 8 * 1024 * 1024;
817 max_chunk_size = calc_size * 2;
818 min_stripe_size = 1 * 1024 * 1024;
819 max_stripes = BTRFS_MAX_DEVS_SYS_CHUNK;
820 } else if (type & BTRFS_BLOCK_GROUP_DATA) {
821 calc_size = 1024 * 1024 * 1024;
822 max_chunk_size = 10 * calc_size;
823 min_stripe_size = 64 * 1024 * 1024;
824 max_stripes = BTRFS_MAX_DEVS(chunk_root);
825 } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
826 calc_size = 1024 * 1024 * 1024;
827 max_chunk_size = 4 * calc_size;
828 min_stripe_size = 32 * 1024 * 1024;
829 max_stripes = BTRFS_MAX_DEVS(chunk_root);
830 }
831 }
832 if (type & BTRFS_BLOCK_GROUP_RAID1) {
833 num_stripes = min_t(u64, 2,
834 btrfs_super_num_devices(info->super_copy));
835 if (num_stripes < 2)
836 return -ENOSPC;
837 min_stripes = 2;
838 }
839 if (type & BTRFS_BLOCK_GROUP_DUP) {
840 num_stripes = 2;
841 min_stripes = 2;
842 }
843 if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
844 num_stripes = btrfs_super_num_devices(info->super_copy);
845 if (num_stripes > max_stripes)
846 num_stripes = max_stripes;
847 min_stripes = 2;
848 }
849 if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
850 num_stripes = btrfs_super_num_devices(info->super_copy);
851 if (num_stripes > max_stripes)
852 num_stripes = max_stripes;
853 if (num_stripes < 4)
854 return -ENOSPC;
855 num_stripes &= ~(u32)1;
856 sub_stripes = 2;
857 min_stripes = 4;
858 }
859 if (type & (BTRFS_BLOCK_GROUP_RAID5)) {
860 num_stripes = btrfs_super_num_devices(info->super_copy);
861 if (num_stripes > max_stripes)
862 num_stripes = max_stripes;
863 if (num_stripes < 2)
864 return -ENOSPC;
865 min_stripes = 2;
866 stripe_len = find_raid56_stripe_len(num_stripes - 1,
867 btrfs_super_stripesize(info->super_copy));
868 }
869 if (type & (BTRFS_BLOCK_GROUP_RAID6)) {
870 num_stripes = btrfs_super_num_devices(info->super_copy);
871 if (num_stripes > max_stripes)
872 num_stripes = max_stripes;
873 if (num_stripes < 3)
874 return -ENOSPC;
875 min_stripes = 3;
876 stripe_len = find_raid56_stripe_len(num_stripes - 2,
877 btrfs_super_stripesize(info->super_copy));
878 }
879
880 /* we don't want a chunk larger than 10% of the FS */
881 percent_max = div_factor(btrfs_super_total_bytes(info->super_copy), 1);
882 max_chunk_size = min(percent_max, max_chunk_size);
883
884 again:
885 if (chunk_bytes_by_type(type, calc_size, num_stripes, sub_stripes) >
886 max_chunk_size) {
887 calc_size = max_chunk_size;
888 calc_size /= num_stripes;
889 calc_size /= stripe_len;
890 calc_size *= stripe_len;
891 }
892 /* we don't want tiny stripes */
893 calc_size = max_t(u64, calc_size, min_stripe_size);
894
895 calc_size /= stripe_len;
896 calc_size *= stripe_len;
897 INIT_LIST_HEAD(&private_devs);
898 cur = dev_list->next;
899 index = 0;
900
901 if (type & BTRFS_BLOCK_GROUP_DUP)
902 min_free = calc_size * 2;
903 else
904 min_free = calc_size;
905
906 /* build a private list of devices we will allocate from */
907 while(index < num_stripes) {
908 device = list_entry(cur, struct btrfs_device, dev_list);
909 ret = btrfs_device_avail_bytes(trans, device, &avail);
910 if (ret)
911 return ret;
912 cur = cur->next;
913 if (avail >= min_free) {
914 list_move_tail(&device->dev_list, &private_devs);
915 index++;
916 if (type & BTRFS_BLOCK_GROUP_DUP)
917 index++;
918 } else if (avail > max_avail)
919 max_avail = avail;
920 if (cur == dev_list)
921 break;
922 }
923 if (index < num_stripes) {
924 list_splice(&private_devs, dev_list);
925 if (index >= min_stripes) {
926 num_stripes = index;
927 if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
928 num_stripes /= sub_stripes;
929 num_stripes *= sub_stripes;
930 }
931 looped = 1;
932 goto again;
933 }
934 if (!looped && max_avail > 0) {
935 looped = 1;
936 calc_size = max_avail;
937 goto again;
938 }
939 return -ENOSPC;
940 }
941 ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
942 &offset);
943 if (ret)
944 return ret;
945 key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
946 key.type = BTRFS_CHUNK_ITEM_KEY;
947 key.offset = offset;
948
949 chunk = kmalloc(btrfs_chunk_item_size(num_stripes), GFP_NOFS);
950 if (!chunk)
951 return -ENOMEM;
952
953 map = kmalloc(btrfs_map_lookup_size(num_stripes), GFP_NOFS);
954 if (!map) {
955 kfree(chunk);
956 return -ENOMEM;
957 }
958
959 stripes = &chunk->stripe;
960 *num_bytes = chunk_bytes_by_type(type, calc_size,
961 num_stripes, sub_stripes);
962 index = 0;
963 while(index < num_stripes) {
964 struct btrfs_stripe *stripe;
965 BUG_ON(list_empty(&private_devs));
966 cur = private_devs.next;
967 device = list_entry(cur, struct btrfs_device, dev_list);
968
969 /* loop over this device again if we're doing a dup group */
970 if (!(type & BTRFS_BLOCK_GROUP_DUP) ||
971 (index == num_stripes - 1))
972 list_move_tail(&device->dev_list, dev_list);
973
974 ret = btrfs_alloc_dev_extent(trans, device,
975 info->chunk_root->root_key.objectid,
976 BTRFS_FIRST_CHUNK_TREE_OBJECTID, key.offset,
977 calc_size, &dev_offset);
978 BUG_ON(ret);
979
980 device->bytes_used += calc_size;
981 ret = btrfs_update_device(trans, device);
982 BUG_ON(ret);
983
984 map->stripes[index].dev = device;
985 map->stripes[index].physical = dev_offset;
986 stripe = stripes + index;
987 btrfs_set_stack_stripe_devid(stripe, device->devid);
988 btrfs_set_stack_stripe_offset(stripe, dev_offset);
989 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
990 index++;
991 }
992 BUG_ON(!list_empty(&private_devs));
993
994 /* key was set above */
995 btrfs_set_stack_chunk_length(chunk, *num_bytes);
996 btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
997 btrfs_set_stack_chunk_stripe_len(chunk, stripe_len);
998 btrfs_set_stack_chunk_type(chunk, type);
999 btrfs_set_stack_chunk_num_stripes(chunk, num_stripes);
1000 btrfs_set_stack_chunk_io_align(chunk, stripe_len);
1001 btrfs_set_stack_chunk_io_width(chunk, stripe_len);
1002 btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
1003 btrfs_set_stack_chunk_sub_stripes(chunk, sub_stripes);
1004 map->sector_size = extent_root->sectorsize;
1005 map->stripe_len = stripe_len;
1006 map->io_align = stripe_len;
1007 map->io_width = stripe_len;
1008 map->type = type;
1009 map->num_stripes = num_stripes;
1010 map->sub_stripes = sub_stripes;
1011
1012 ret = btrfs_insert_item(trans, chunk_root, &key, chunk,
1013 btrfs_chunk_item_size(num_stripes));
1014 BUG_ON(ret);
1015 *start = key.offset;;
1016
1017 map->ce.start = key.offset;
1018 map->ce.size = *num_bytes;
1019
1020 ret = insert_cache_extent(&info->mapping_tree.cache_tree, &map->ce);
1021 BUG_ON(ret);
1022
1023 if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
1024 ret = btrfs_add_system_chunk(trans, chunk_root, &key,
1025 chunk, btrfs_chunk_item_size(num_stripes));
1026 BUG_ON(ret);
1027 }
1028
1029 kfree(chunk);
1030 return ret;
1031 }
1032
1033 int btrfs_alloc_data_chunk(struct btrfs_trans_handle *trans,
1034 struct btrfs_root *extent_root, u64 *start,
1035 u64 num_bytes, u64 type)
1036 {
1037 u64 dev_offset;
1038 struct btrfs_fs_info *info = extent_root->fs_info;
1039 struct btrfs_root *chunk_root = info->chunk_root;
1040 struct btrfs_stripe *stripes;
1041 struct btrfs_device *device = NULL;
1042 struct btrfs_chunk *chunk;
1043 struct list_head *dev_list = &info->fs_devices->devices;
1044 struct list_head *cur;
1045 struct map_lookup *map;
1046 u64 calc_size = 8 * 1024 * 1024;
1047 int num_stripes = 1;
1048 int sub_stripes = 0;
1049 int ret;
1050 int index;
1051 int stripe_len = BTRFS_STRIPE_LEN;
1052 struct btrfs_key key;
1053
1054 key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
1055 key.type = BTRFS_CHUNK_ITEM_KEY;
1056 ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
1057 &key.offset);
1058 if (ret)
1059 return ret;
1060
1061 chunk = kmalloc(btrfs_chunk_item_size(num_stripes), GFP_NOFS);
1062 if (!chunk)
1063 return -ENOMEM;
1064
1065 map = kmalloc(btrfs_map_lookup_size(num_stripes), GFP_NOFS);
1066 if (!map) {
1067 kfree(chunk);
1068 return -ENOMEM;
1069 }
1070
1071 stripes = &chunk->stripe;
1072 calc_size = num_bytes;
1073
1074 index = 0;
1075 cur = dev_list->next;
1076 device = list_entry(cur, struct btrfs_device, dev_list);
1077
1078 while (index < num_stripes) {
1079 struct btrfs_stripe *stripe;
1080
1081 ret = btrfs_alloc_dev_extent(trans, device,
1082 info->chunk_root->root_key.objectid,
1083 BTRFS_FIRST_CHUNK_TREE_OBJECTID, key.offset,
1084 calc_size, &dev_offset);
1085 BUG_ON(ret);
1086
1087 device->bytes_used += calc_size;
1088 ret = btrfs_update_device(trans, device);
1089 BUG_ON(ret);
1090
1091 map->stripes[index].dev = device;
1092 map->stripes[index].physical = dev_offset;
1093 stripe = stripes + index;
1094 btrfs_set_stack_stripe_devid(stripe, device->devid);
1095 btrfs_set_stack_stripe_offset(stripe, dev_offset);
1096 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
1097 index++;
1098 }
1099
1100 /* key was set above */
1101 btrfs_set_stack_chunk_length(chunk, num_bytes);
1102 btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
1103 btrfs_set_stack_chunk_stripe_len(chunk, stripe_len);
1104 btrfs_set_stack_chunk_type(chunk, type);
1105 btrfs_set_stack_chunk_num_stripes(chunk, num_stripes);
1106 btrfs_set_stack_chunk_io_align(chunk, stripe_len);
1107 btrfs_set_stack_chunk_io_width(chunk, stripe_len);
1108 btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
1109 btrfs_set_stack_chunk_sub_stripes(chunk, sub_stripes);
1110 map->sector_size = extent_root->sectorsize;
1111 map->stripe_len = stripe_len;
1112 map->io_align = stripe_len;
1113 map->io_width = stripe_len;
1114 map->type = type;
1115 map->num_stripes = num_stripes;
1116 map->sub_stripes = sub_stripes;
1117
1118 ret = btrfs_insert_item(trans, chunk_root, &key, chunk,
1119 btrfs_chunk_item_size(num_stripes));
1120 BUG_ON(ret);
1121 *start = key.offset;
1122
1123 map->ce.start = key.offset;
1124 map->ce.size = num_bytes;
1125
1126 ret = insert_cache_extent(&info->mapping_tree.cache_tree, &map->ce);
1127 BUG_ON(ret);
1128
1129 kfree(chunk);
1130 return ret;
1131 }
1132
1133 int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
1134 {
1135 struct cache_extent *ce;
1136 struct map_lookup *map;
1137 int ret;
1138
1139 ce = search_cache_extent(&map_tree->cache_tree, logical);
1140 if (!ce) {
1141 fprintf(stderr, "No mapping for %llu-%llu\n",
1142 (unsigned long long)logical,
1143 (unsigned long long)logical+len);
1144 return 1;
1145 }
1146 if (ce->start > logical || ce->start + ce->size < logical) {
1147 fprintf(stderr, "Invalid mapping for %llu-%llu, got "
1148 "%llu-%llu\n", (unsigned long long)logical,
1149 (unsigned long long)logical+len,
1150 (unsigned long long)ce->start,
1151 (unsigned long long)ce->start + ce->size);
1152 return 1;
1153 }
1154 map = container_of(ce, struct map_lookup, ce);
1155
1156 if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
1157 ret = map->num_stripes;
1158 else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
1159 ret = map->sub_stripes;
1160 else if (map->type & BTRFS_BLOCK_GROUP_RAID5)
1161 ret = 2;
1162 else if (map->type & BTRFS_BLOCK_GROUP_RAID6)
1163 ret = 3;
1164 else
1165 ret = 1;
1166 return ret;
1167 }
1168
1169 int btrfs_next_metadata(struct btrfs_mapping_tree *map_tree, u64 *logical,
1170 u64 *size)
1171 {
1172 struct cache_extent *ce;
1173 struct map_lookup *map;
1174
1175 ce = search_cache_extent(&map_tree->cache_tree, *logical);
1176
1177 while (ce) {
1178 ce = next_cache_extent(ce);
1179 if (!ce)
1180 return -ENOENT;
1181
1182 map = container_of(ce, struct map_lookup, ce);
1183 if (map->type & BTRFS_BLOCK_GROUP_METADATA) {
1184 *logical = ce->start;
1185 *size = ce->size;
1186 return 0;
1187 }
1188 }
1189
1190 return -ENOENT;
1191 }
1192
1193 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
1194 u64 chunk_start, u64 physical, u64 devid,
1195 u64 **logical, int *naddrs, int *stripe_len)
1196 {
1197 struct cache_extent *ce;
1198 struct map_lookup *map;
1199 u64 *buf;
1200 u64 bytenr;
1201 u64 length;
1202 u64 stripe_nr;
1203 u64 rmap_len;
1204 int i, j, nr = 0;
1205
1206 ce = search_cache_extent(&map_tree->cache_tree, chunk_start);
1207 BUG_ON(!ce);
1208 map = container_of(ce, struct map_lookup, ce);
1209
1210 length = ce->size;
1211 rmap_len = map->stripe_len;
1212 if (map->type & BTRFS_BLOCK_GROUP_RAID10)
1213 length = ce->size / (map->num_stripes / map->sub_stripes);
1214 else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
1215 length = ce->size / map->num_stripes;
1216 else if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
1217 BTRFS_BLOCK_GROUP_RAID6)) {
1218 length = ce->size / nr_data_stripes(map);
1219 rmap_len = map->stripe_len * nr_data_stripes(map);
1220 }
1221
1222 buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
1223
1224 for (i = 0; i < map->num_stripes; i++) {
1225 if (devid && map->stripes[i].dev->devid != devid)
1226 continue;
1227 if (map->stripes[i].physical > physical ||
1228 map->stripes[i].physical + length <= physical)
1229 continue;
1230
1231 stripe_nr = (physical - map->stripes[i].physical) /
1232 map->stripe_len;
1233
1234 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1235 stripe_nr = (stripe_nr * map->num_stripes + i) /
1236 map->sub_stripes;
1237 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
1238 stripe_nr = stripe_nr * map->num_stripes + i;
1239 } /* else if RAID[56], multiply by nr_data_stripes().
1240 * Alternatively, just use rmap_len below instead of
1241 * map->stripe_len */
1242
1243 bytenr = ce->start + stripe_nr * rmap_len;
1244 for (j = 0; j < nr; j++) {
1245 if (buf[j] == bytenr)
1246 break;
1247 }
1248 if (j == nr)
1249 buf[nr++] = bytenr;
1250 }
1251
1252 *logical = buf;
1253 *naddrs = nr;
1254 *stripe_len = rmap_len;
1255
1256 return 0;
1257 }
1258
1259 static inline int parity_smaller(u64 a, u64 b)
1260 {
1261 return a > b;
1262 }
1263
1264 /* Bubble-sort the stripe set to put the parity/syndrome stripes last */
1265 static void sort_parity_stripes(struct btrfs_multi_bio *bbio, u64 *raid_map)
1266 {
1267 struct btrfs_bio_stripe s;
1268 int i;
1269 u64 l;
1270 int again = 1;
1271
1272 while (again) {
1273 again = 0;
1274 for (i = 0; i < bbio->num_stripes - 1; i++) {
1275 if (parity_smaller(raid_map[i], raid_map[i+1])) {
1276 s = bbio->stripes[i];
1277 l = raid_map[i];
1278 bbio->stripes[i] = bbio->stripes[i+1];
1279 raid_map[i] = raid_map[i+1];
1280 bbio->stripes[i+1] = s;
1281 raid_map[i+1] = l;
1282 again = 1;
1283 }
1284 }
1285 }
1286 }
1287
1288 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
1289 u64 logical, u64 *length,
1290 struct btrfs_multi_bio **multi_ret, int mirror_num,
1291 u64 **raid_map_ret)
1292 {
1293 return __btrfs_map_block(map_tree, rw, logical, length, NULL,
1294 multi_ret, mirror_num, raid_map_ret);
1295 }
1296
1297 int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
1298 u64 logical, u64 *length, u64 *type,
1299 struct btrfs_multi_bio **multi_ret, int mirror_num,
1300 u64 **raid_map_ret)
1301 {
1302 struct cache_extent *ce;
1303 struct map_lookup *map;
1304 u64 offset;
1305 u64 stripe_offset;
1306 u64 stripe_nr;
1307 u64 *raid_map = NULL;
1308 int stripes_allocated = 8;
1309 int stripes_required = 1;
1310 int stripe_index;
1311 int i;
1312 struct btrfs_multi_bio *multi = NULL;
1313
1314 if (multi_ret && rw == READ) {
1315 stripes_allocated = 1;
1316 }
1317 again:
1318 ce = search_cache_extent(&map_tree->cache_tree, logical);
1319 if (!ce) {
1320 kfree(multi);
1321 return -ENOENT;
1322 }
1323 if (ce->start > logical || ce->start + ce->size < logical) {
1324 kfree(multi);
1325 return -ENOENT;
1326 }
1327
1328 if (multi_ret) {
1329 multi = kzalloc(btrfs_multi_bio_size(stripes_allocated),
1330 GFP_NOFS);
1331 if (!multi)
1332 return -ENOMEM;
1333 }
1334 map = container_of(ce, struct map_lookup, ce);
1335 offset = logical - ce->start;
1336
1337 if (rw == WRITE) {
1338 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
1339 BTRFS_BLOCK_GROUP_DUP)) {
1340 stripes_required = map->num_stripes;
1341 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1342 stripes_required = map->sub_stripes;
1343 }
1344 }
1345 if (map->type & (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6)
1346 && multi_ret && ((rw & WRITE) || mirror_num > 1) && raid_map_ret) {
1347 /* RAID[56] write or recovery. Return all stripes */
1348 stripes_required = map->num_stripes;
1349
1350 /* Only allocate the map if we've already got a large enough multi_ret */
1351 if (stripes_allocated >= stripes_required) {
1352 raid_map = kmalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
1353 if (!raid_map) {
1354 kfree(multi);
1355 return -ENOMEM;
1356 }
1357 }
1358 }
1359
1360 /* if our multi bio struct is too small, back off and try again */
1361 if (multi_ret && stripes_allocated < stripes_required) {
1362 stripes_allocated = stripes_required;
1363 kfree(multi);
1364 multi = NULL;
1365 goto again;
1366 }
1367 stripe_nr = offset;
1368 /*
1369 * stripe_nr counts the total number of stripes we have to stride
1370 * to get to this block
1371 */
1372 stripe_nr = stripe_nr / map->stripe_len;
1373
1374 stripe_offset = stripe_nr * map->stripe_len;
1375 BUG_ON(offset < stripe_offset);
1376
1377 /* stripe_offset is the offset of this block in its stripe*/
1378 stripe_offset = offset - stripe_offset;
1379
1380 if (map->type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
1381 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
1382 BTRFS_BLOCK_GROUP_RAID10 |
1383 BTRFS_BLOCK_GROUP_DUP)) {
1384 /* we limit the length of each bio to what fits in a stripe */
1385 *length = min_t(u64, ce->size - offset,
1386 map->stripe_len - stripe_offset);
1387 } else {
1388 *length = ce->size - offset;
1389 }
1390
1391 if (!multi_ret)
1392 goto out;
1393
1394 multi->num_stripes = 1;
1395 stripe_index = 0;
1396 if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
1397 if (rw == WRITE)
1398 multi->num_stripes = map->num_stripes;
1399 else if (mirror_num)
1400 stripe_index = mirror_num - 1;
1401 else
1402 stripe_index = stripe_nr % map->num_stripes;
1403 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1404 int factor = map->num_stripes / map->sub_stripes;
1405
1406 stripe_index = stripe_nr % factor;
1407 stripe_index *= map->sub_stripes;
1408
1409 if (rw == WRITE)
1410 multi->num_stripes = map->sub_stripes;
1411 else if (mirror_num)
1412 stripe_index += mirror_num - 1;
1413
1414 stripe_nr = stripe_nr / factor;
1415 } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
1416 if (rw == WRITE)
1417 multi->num_stripes = map->num_stripes;
1418 else if (mirror_num)
1419 stripe_index = mirror_num - 1;
1420 } else if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
1421 BTRFS_BLOCK_GROUP_RAID6)) {
1422
1423 if (raid_map) {
1424 int rot;
1425 u64 tmp;
1426 u64 raid56_full_stripe_start;
1427 u64 full_stripe_len = nr_data_stripes(map) * map->stripe_len;
1428
1429 /*
1430 * align the start of our data stripe in the logical
1431 * address space
1432 */
1433 raid56_full_stripe_start = offset / full_stripe_len;
1434 raid56_full_stripe_start *= full_stripe_len;
1435
1436 /* get the data stripe number */
1437 stripe_nr = raid56_full_stripe_start / map->stripe_len;
1438 stripe_nr = stripe_nr / nr_data_stripes(map);
1439
1440 /* Work out the disk rotation on this stripe-set */
1441 rot = stripe_nr % map->num_stripes;
1442
1443 /* Fill in the logical address of each stripe */
1444 tmp = stripe_nr * nr_data_stripes(map);
1445
1446 for (i = 0; i < nr_data_stripes(map); i++)
1447 raid_map[(i+rot) % map->num_stripes] =
1448 ce->start + (tmp + i) * map->stripe_len;
1449
1450 raid_map[(i+rot) % map->num_stripes] = BTRFS_RAID5_P_STRIPE;
1451 if (map->type & BTRFS_BLOCK_GROUP_RAID6)
1452 raid_map[(i+rot+1) % map->num_stripes] = BTRFS_RAID6_Q_STRIPE;
1453
1454 *length = map->stripe_len;
1455 stripe_index = 0;
1456 stripe_offset = 0;
1457 multi->num_stripes = map->num_stripes;
1458 } else {
1459 stripe_index = stripe_nr % nr_data_stripes(map);
1460 stripe_nr = stripe_nr / nr_data_stripes(map);
1461
1462 /*
1463 * Mirror #0 or #1 means the original data block.
1464 * Mirror #2 is RAID5 parity block.
1465 * Mirror #3 is RAID6 Q block.
1466 */
1467 if (mirror_num > 1)
1468 stripe_index = nr_data_stripes(map) + mirror_num - 2;
1469
1470 /* We distribute the parity blocks across stripes */
1471 stripe_index = (stripe_nr + stripe_index) % map->num_stripes;
1472 }
1473 } else {
1474 /*
1475 * after this do_div call, stripe_nr is the number of stripes
1476 * on this device we have to walk to find the data, and
1477 * stripe_index is the number of our device in the stripe array
1478 */
1479 stripe_index = stripe_nr % map->num_stripes;
1480 stripe_nr = stripe_nr / map->num_stripes;
1481 }
1482 BUG_ON(stripe_index >= map->num_stripes);
1483
1484 for (i = 0; i < multi->num_stripes; i++) {
1485 multi->stripes[i].physical =
1486 map->stripes[stripe_index].physical + stripe_offset +
1487 stripe_nr * map->stripe_len;
1488 multi->stripes[i].dev = map->stripes[stripe_index].dev;
1489 stripe_index++;
1490 }
1491 *multi_ret = multi;
1492
1493 if (type)
1494 *type = map->type;
1495
1496 if (raid_map) {
1497 sort_parity_stripes(multi, raid_map);
1498 *raid_map_ret = raid_map;
1499 }
1500 out:
1501 return 0;
1502 }
1503
1504 struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
1505 u8 *uuid, u8 *fsid)
1506 {
1507 struct btrfs_device *device;
1508 struct btrfs_fs_devices *cur_devices;
1509
1510 cur_devices = root->fs_info->fs_devices;
1511 while (cur_devices) {
1512 if (!fsid ||
1513 !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
1514 device = __find_device(&cur_devices->devices,
1515 devid, uuid);
1516 if (device)
1517 return device;
1518 }
1519 cur_devices = cur_devices->seed;
1520 }
1521 return NULL;
1522 }
1523
1524 struct btrfs_device *
1525 btrfs_find_device_by_devid(struct btrfs_fs_devices *fs_devices,
1526 u64 devid, int instance)
1527 {
1528 struct list_head *head = &fs_devices->devices;
1529 struct btrfs_device *dev;
1530 int num_found = 0;
1531
1532 list_for_each_entry(dev, head, dev_list) {
1533 if (dev->devid == devid && num_found++ == instance)
1534 return dev;
1535 }
1536 return NULL;
1537 }
1538
1539 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
1540 {
1541 struct cache_extent *ce;
1542 struct map_lookup *map;
1543 struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
1544 int readonly = 0;
1545 int i;
1546
1547 /*
1548 * During chunk recovering, we may fail to find block group's
1549 * corresponding chunk, we will rebuild it later
1550 */
1551 ce = search_cache_extent(&map_tree->cache_tree, chunk_offset);
1552 if (!root->fs_info->is_chunk_recover)
1553 BUG_ON(!ce);
1554 else
1555 return 0;
1556
1557 map = container_of(ce, struct map_lookup, ce);
1558 for (i = 0; i < map->num_stripes; i++) {
1559 if (!map->stripes[i].dev->writeable) {
1560 readonly = 1;
1561 break;
1562 }
1563 }
1564
1565 return readonly;
1566 }
1567
1568 static struct btrfs_device *fill_missing_device(u64 devid)
1569 {
1570 struct btrfs_device *device;
1571
1572 device = kzalloc(sizeof(*device), GFP_NOFS);
1573 device->devid = devid;
1574 device->fd = -1;
1575 return device;
1576 }
1577
1578 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
1579 struct extent_buffer *leaf,
1580 struct btrfs_chunk *chunk)
1581 {
1582 struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
1583 struct map_lookup *map;
1584 struct cache_extent *ce;
1585 u64 logical;
1586 u64 length;
1587 u64 devid;
1588 u8 uuid[BTRFS_UUID_SIZE];
1589 int num_stripes;
1590 int ret;
1591 int i;
1592
1593 logical = key->offset;
1594 length = btrfs_chunk_length(leaf, chunk);
1595
1596 ce = search_cache_extent(&map_tree->cache_tree, logical);
1597
1598 /* already mapped? */
1599 if (ce && ce->start <= logical && ce->start + ce->size > logical) {
1600 return 0;
1601 }
1602
1603 num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
1604 map = kmalloc(btrfs_map_lookup_size(num_stripes), GFP_NOFS);
1605 if (!map)
1606 return -ENOMEM;
1607
1608 map->ce.start = logical;
1609 map->ce.size = length;
1610 map->num_stripes = num_stripes;
1611 map->io_width = btrfs_chunk_io_width(leaf, chunk);
1612 map->io_align = btrfs_chunk_io_align(leaf, chunk);
1613 map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
1614 map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
1615 map->type = btrfs_chunk_type(leaf, chunk);
1616 map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
1617
1618 for (i = 0; i < num_stripes; i++) {
1619 map->stripes[i].physical =
1620 btrfs_stripe_offset_nr(leaf, chunk, i);
1621 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
1622 read_extent_buffer(leaf, uuid, (unsigned long)
1623 btrfs_stripe_dev_uuid_nr(chunk, i),
1624 BTRFS_UUID_SIZE);
1625 map->stripes[i].dev = btrfs_find_device(root, devid, uuid,
1626 NULL);
1627 if (!map->stripes[i].dev) {
1628 map->stripes[i].dev = fill_missing_device(devid);
1629 printf("warning, device %llu is missing\n",
1630 (unsigned long long)devid);
1631 }
1632
1633 }
1634 ret = insert_cache_extent(&map_tree->cache_tree, &map->ce);
1635 BUG_ON(ret);
1636
1637 return 0;
1638 }
1639
1640 static int fill_device_from_item(struct extent_buffer *leaf,
1641 struct btrfs_dev_item *dev_item,
1642 struct btrfs_device *device)
1643 {
1644 unsigned long ptr;
1645
1646 device->devid = btrfs_device_id(leaf, dev_item);
1647 device->total_bytes = btrfs_device_total_bytes(leaf, dev_item);
1648 device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
1649 device->type = btrfs_device_type(leaf, dev_item);
1650 device->io_align = btrfs_device_io_align(leaf, dev_item);
1651 device->io_width = btrfs_device_io_width(leaf, dev_item);
1652 device->sector_size = btrfs_device_sector_size(leaf, dev_item);
1653
1654 ptr = (unsigned long)btrfs_device_uuid(dev_item);
1655 read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1656
1657 return 0;
1658 }
1659
1660 static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
1661 {
1662 struct btrfs_fs_devices *fs_devices;
1663 int ret;
1664
1665 fs_devices = root->fs_info->fs_devices->seed;
1666 while (fs_devices) {
1667 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
1668 ret = 0;
1669 goto out;
1670 }
1671 fs_devices = fs_devices->seed;
1672 }
1673
1674 fs_devices = find_fsid(fsid);
1675 if (!fs_devices) {
1676 /* missing all seed devices */
1677 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
1678 if (!fs_devices) {
1679 ret = -ENOMEM;
1680 goto out;
1681 }
1682 INIT_LIST_HEAD(&fs_devices->devices);
1683 list_add(&fs_devices->list, &fs_uuids);
1684 memcpy(fs_devices->fsid, fsid, BTRFS_FSID_SIZE);
1685 }
1686
1687 ret = btrfs_open_devices(fs_devices, O_RDONLY);
1688 if (ret)
1689 goto out;
1690
1691 fs_devices->seed = root->fs_info->fs_devices->seed;
1692 root->fs_info->fs_devices->seed = fs_devices;
1693 out:
1694 return ret;
1695 }
1696
1697 static int read_one_dev(struct btrfs_root *root,
1698 struct extent_buffer *leaf,
1699 struct btrfs_dev_item *dev_item)
1700 {
1701 struct btrfs_device *device;
1702 u64 devid;
1703 int ret = 0;
1704 u8 fs_uuid[BTRFS_UUID_SIZE];
1705 u8 dev_uuid[BTRFS_UUID_SIZE];
1706
1707 devid = btrfs_device_id(leaf, dev_item);
1708 read_extent_buffer(leaf, dev_uuid,
1709 (unsigned long)btrfs_device_uuid(dev_item),
1710 BTRFS_UUID_SIZE);
1711 read_extent_buffer(leaf, fs_uuid,
1712 (unsigned long)btrfs_device_fsid(dev_item),
1713 BTRFS_UUID_SIZE);
1714
1715 if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
1716 ret = open_seed_devices(root, fs_uuid);
1717 if (ret)
1718 return ret;
1719 }
1720
1721 device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
1722 if (!device) {
1723 printk("warning devid %llu not found already\n",
1724 (unsigned long long)devid);
1725 device = kzalloc(sizeof(*device), GFP_NOFS);
1726 if (!device)
1727 return -ENOMEM;
1728 device->fd = -1;
1729 list_add(&device->dev_list,
1730 &root->fs_info->fs_devices->devices);
1731 }
1732
1733 fill_device_from_item(leaf, dev_item, device);
1734 device->dev_root = root->fs_info->dev_root;
1735 return ret;
1736 }
1737
1738 int btrfs_read_sys_array(struct btrfs_root *root)
1739 {
1740 struct btrfs_super_block *super_copy = root->fs_info->super_copy;
1741 struct extent_buffer *sb;
1742 struct btrfs_disk_key *disk_key;
1743 struct btrfs_chunk *chunk;
1744 struct btrfs_key key;
1745 u32 num_stripes;
1746 u32 len = 0;
1747 u8 *ptr;
1748 u8 *array_end;
1749 int ret = 0;
1750
1751 sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
1752 BTRFS_SUPER_INFO_SIZE);
1753 if (!sb)
1754 return -ENOMEM;
1755 btrfs_set_buffer_uptodate(sb);
1756 write_extent_buffer(sb, super_copy, 0, sizeof(*super_copy));
1757 array_end = ((u8 *)super_copy->sys_chunk_array) +
1758 btrfs_super_sys_array_size(super_copy);
1759
1760 /*
1761 * we do this loop twice, once for the device items and
1762 * once for all of the chunks. This way there are device
1763 * structs filled in for every chunk
1764 */
1765 ptr = super_copy->sys_chunk_array;
1766
1767 while (ptr < array_end) {
1768 disk_key = (struct btrfs_disk_key *)ptr;
1769 btrfs_disk_key_to_cpu(&key, disk_key);
1770
1771 len = sizeof(*disk_key);
1772 ptr += len;
1773
1774 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
1775 chunk = (struct btrfs_chunk *)(ptr - (u8 *)super_copy);
1776 ret = read_one_chunk(root, &key, sb, chunk);
1777 if (ret)
1778 break;
1779 num_stripes = btrfs_chunk_num_stripes(sb, chunk);
1780 len = btrfs_chunk_item_size(num_stripes);
1781 } else {
1782 BUG();
1783 }
1784 ptr += len;
1785 }
1786 free_extent_buffer(sb);
1787 return ret;
1788 }
1789
1790 int btrfs_read_chunk_tree(struct btrfs_root *root)
1791 {
1792 struct btrfs_path *path;
1793 struct extent_buffer *leaf;
1794 struct btrfs_key key;
1795 struct btrfs_key found_key;
1796 int ret;
1797 int slot;
1798
1799 root = root->fs_info->chunk_root;
1800
1801 path = btrfs_alloc_path();
1802 if (!path)
1803 return -ENOMEM;
1804
1805 /*
1806 * Read all device items, and then all the chunk items. All
1807 * device items are found before any chunk item (their object id
1808 * is smaller than the lowest possible object id for a chunk
1809 * item - BTRFS_FIRST_CHUNK_TREE_OBJECTID).
1810 */
1811 key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1812 key.offset = 0;
1813 key.type = 0;
1814 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1815 if (ret < 0)
1816 goto error;
1817 while(1) {
1818 leaf = path->nodes[0];
1819 slot = path->slots[0];
1820 if (slot >= btrfs_header_nritems(leaf)) {
1821 ret = btrfs_next_leaf(root, path);
1822 if (ret == 0)
1823 continue;
1824 if (ret < 0)
1825 goto error;
1826 break;
1827 }
1828 btrfs_item_key_to_cpu(leaf, &found_key, slot);
1829 if (found_key.type == BTRFS_DEV_ITEM_KEY) {
1830 struct btrfs_dev_item *dev_item;
1831 dev_item = btrfs_item_ptr(leaf, slot,
1832 struct btrfs_dev_item);
1833 ret = read_one_dev(root, leaf, dev_item);
1834 BUG_ON(ret);
1835 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
1836 struct btrfs_chunk *chunk;
1837 chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
1838 ret = read_one_chunk(root, &found_key, leaf, chunk);
1839 BUG_ON(ret);
1840 }
1841 path->slots[0]++;
1842 }
1843
1844 ret = 0;
1845 error:
1846 btrfs_free_path(path);
1847 return ret;
1848 }
1849
1850 struct list_head *btrfs_scanned_uuids(void)
1851 {
1852 return &fs_uuids;
1853 }
1854
1855 static int rmw_eb(struct btrfs_fs_info *info,
1856 struct extent_buffer *eb, struct extent_buffer *orig_eb)
1857 {
1858 int ret;
1859 unsigned long orig_off = 0;
1860 unsigned long dest_off = 0;
1861 unsigned long copy_len = eb->len;
1862
1863 ret = read_whole_eb(info, eb, 0);
1864 if (ret)
1865 return ret;
1866
1867 if (eb->start + eb->len <= orig_eb->start ||
1868 eb->start >= orig_eb->start + orig_eb->len)
1869 return 0;
1870 /*
1871 * | ----- orig_eb ------- |
1872 * | ----- stripe ------- |
1873 * | ----- orig_eb ------- |
1874 * | ----- orig_eb ------- |
1875 */
1876 if (eb->start > orig_eb->start)
1877 orig_off = eb->start - orig_eb->start;
1878 if (orig_eb->start > eb->start)
1879 dest_off = orig_eb->start - eb->start;
1880
1881 if (copy_len > orig_eb->len - orig_off)
1882 copy_len = orig_eb->len - orig_off;
1883 if (copy_len > eb->len - dest_off)
1884 copy_len = eb->len - dest_off;
1885
1886 memcpy(eb->data + dest_off, orig_eb->data + orig_off, copy_len);
1887 return 0;
1888 }
1889
1890 static void split_eb_for_raid56(struct btrfs_fs_info *info,
1891 struct extent_buffer *orig_eb,
1892 struct extent_buffer **ebs,
1893 u64 stripe_len, u64 *raid_map,
1894 int num_stripes)
1895 {
1896 struct extent_buffer *eb;
1897 u64 start = orig_eb->start;
1898 u64 this_eb_start;
1899 int i;
1900 int ret;
1901
1902 for (i = 0; i < num_stripes; i++) {
1903 if (raid_map[i] >= BTRFS_RAID5_P_STRIPE)
1904 break;
1905
1906 eb = malloc(sizeof(struct extent_buffer) + stripe_len);
1907 if (!eb)
1908 BUG();
1909 memset(eb, 0, sizeof(struct extent_buffer) + stripe_len);
1910
1911 eb->start = raid_map[i];
1912 eb->len = stripe_len;
1913 eb->refs = 1;
1914 eb->flags = 0;
1915 eb->fd = -1;
1916 eb->dev_bytenr = (u64)-1;
1917
1918 this_eb_start = raid_map[i];
1919
1920 if (start > this_eb_start ||
1921 start + orig_eb->len < this_eb_start + stripe_len) {
1922 ret = rmw_eb(info, eb, orig_eb);
1923 BUG_ON(ret);
1924 } else {
1925 memcpy(eb->data, orig_eb->data + eb->start - start, stripe_len);
1926 }
1927 ebs[i] = eb;
1928 }
1929 }
1930
1931 int write_raid56_with_parity(struct btrfs_fs_info *info,
1932 struct extent_buffer *eb,
1933 struct btrfs_multi_bio *multi,
1934 u64 stripe_len, u64 *raid_map)
1935 {
1936 struct extent_buffer **ebs, *p_eb = NULL, *q_eb = NULL;
1937 int i;
1938 int j;
1939 int ret;
1940 int alloc_size = eb->len;
1941
1942 ebs = kmalloc(sizeof(*ebs) * multi->num_stripes, GFP_NOFS);
1943 BUG_ON(!ebs);
1944
1945 if (stripe_len > alloc_size)
1946 alloc_size = stripe_len;
1947
1948 split_eb_for_raid56(info, eb, ebs, stripe_len, raid_map,
1949 multi->num_stripes);
1950
1951 for (i = 0; i < multi->num_stripes; i++) {
1952 struct extent_buffer *new_eb;
1953 if (raid_map[i] < BTRFS_RAID5_P_STRIPE) {
1954 ebs[i]->dev_bytenr = multi->stripes[i].physical;
1955 ebs[i]->fd = multi->stripes[i].dev->fd;
1956 multi->stripes[i].dev->total_ios++;
1957 BUG_ON(ebs[i]->start != raid_map[i]);
1958 continue;
1959 }
1960 new_eb = kmalloc(sizeof(*eb) + alloc_size, GFP_NOFS);
1961 BUG_ON(!new_eb);
1962 new_eb->dev_bytenr = multi->stripes[i].physical;
1963 new_eb->fd = multi->stripes[i].dev->fd;
1964 multi->stripes[i].dev->total_ios++;
1965 new_eb->len = stripe_len;
1966
1967 if (raid_map[i] == BTRFS_RAID5_P_STRIPE)
1968 p_eb = new_eb;
1969 else if (raid_map[i] == BTRFS_RAID6_Q_STRIPE)
1970 q_eb = new_eb;
1971 }
1972 if (q_eb) {
1973 void **pointers;
1974
1975 pointers = kmalloc(sizeof(*pointers) * multi->num_stripes,
1976 GFP_NOFS);
1977 BUG_ON(!pointers);
1978
1979 ebs[multi->num_stripes - 2] = p_eb;
1980 ebs[multi->num_stripes - 1] = q_eb;
1981
1982 for (i = 0; i < multi->num_stripes; i++)
1983 pointers[i] = ebs[i]->data;
1984
1985 raid6_gen_syndrome(multi->num_stripes, stripe_len, pointers);
1986 kfree(pointers);
1987 } else {
1988 ebs[multi->num_stripes - 1] = p_eb;
1989 memcpy(p_eb->data, ebs[0]->data, stripe_len);
1990 for (j = 1; j < multi->num_stripes - 1; j++) {
1991 for (i = 0; i < stripe_len; i += sizeof(unsigned long)) {
1992 *(unsigned long *)(p_eb->data + i) ^=
1993 *(unsigned long *)(ebs[j]->data + i);
1994 }
1995 }
1996 }
1997
1998 for (i = 0; i < multi->num_stripes; i++) {
1999 ret = write_extent_to_disk(ebs[i]);
2000 BUG_ON(ret);
2001 if (ebs[i] != eb)
2002 kfree(ebs[i]);
2003 }
2004
2005 kfree(ebs);
2006
2007 return 0;
2008 }
(deprecated) Btrfs progs developments and patch integration