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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) STRATO AG 2013. All rights reserved.
4 */
5
6#include <linux/kthread.h>
7#include <linux/uuid.h>
8#include <linux/unaligned.h>
9#include "messages.h"
10#include "ctree.h"
11#include "transaction.h"
12#include "disk-io.h"
13#include "fs.h"
14#include "accessors.h"
15#include "uuid-tree.h"
16#include "ioctl.h"
17
18static void btrfs_uuid_to_key(const u8 *uuid, u8 type, struct btrfs_key *key)
19{
20 key->type = type;
21 key->objectid = get_unaligned_le64(uuid);
22 key->offset = get_unaligned_le64(uuid + sizeof(u64));
23}
24
25/* return -ENOENT for !found, < 0 for errors, or 0 if an item was found */
26static int btrfs_uuid_tree_lookup(struct btrfs_root *uuid_root, const u8 *uuid,
27 u8 type, u64 subid)
28{
29 int ret;
30 struct btrfs_path *path = NULL;
31 struct extent_buffer *eb;
32 int slot;
33 u32 item_size;
34 unsigned long offset;
35 struct btrfs_key key;
36
37 if (WARN_ON_ONCE(!uuid_root)) {
38 ret = -ENOENT;
39 goto out;
40 }
41
42 path = btrfs_alloc_path();
43 if (!path) {
44 ret = -ENOMEM;
45 goto out;
46 }
47
48 btrfs_uuid_to_key(uuid, type, &key);
49 ret = btrfs_search_slot(NULL, uuid_root, &key, path, 0, 0);
50 if (ret < 0) {
51 goto out;
52 } else if (ret > 0) {
53 ret = -ENOENT;
54 goto out;
55 }
56
57 eb = path->nodes[0];
58 slot = path->slots[0];
59 item_size = btrfs_item_size(eb, slot);
60 offset = btrfs_item_ptr_offset(eb, slot);
61 ret = -ENOENT;
62
63 if (!IS_ALIGNED(item_size, sizeof(u64))) {
64 btrfs_warn(uuid_root->fs_info,
65 "uuid item with illegal size %lu!",
66 (unsigned long)item_size);
67 goto out;
68 }
69 while (item_size) {
70 __le64 data;
71
72 read_extent_buffer(eb, &data, offset, sizeof(data));
73 if (le64_to_cpu(data) == subid) {
74 ret = 0;
75 break;
76 }
77 offset += sizeof(data);
78 item_size -= sizeof(data);
79 }
80
81out:
82 btrfs_free_path(path);
83 return ret;
84}
85
86int btrfs_uuid_tree_add(struct btrfs_trans_handle *trans, const u8 *uuid, u8 type,
87 u64 subid_cpu)
88{
89 struct btrfs_fs_info *fs_info = trans->fs_info;
90 struct btrfs_root *uuid_root = fs_info->uuid_root;
91 int ret;
92 struct btrfs_path *path = NULL;
93 struct btrfs_key key;
94 struct extent_buffer *eb;
95 int slot;
96 unsigned long offset;
97 __le64 subid_le;
98
99 ret = btrfs_uuid_tree_lookup(uuid_root, uuid, type, subid_cpu);
100 if (ret != -ENOENT)
101 return ret;
102
103 if (WARN_ON_ONCE(!uuid_root)) {
104 ret = -EINVAL;
105 goto out;
106 }
107
108 btrfs_uuid_to_key(uuid, type, &key);
109
110 path = btrfs_alloc_path();
111 if (!path) {
112 ret = -ENOMEM;
113 goto out;
114 }
115
116 ret = btrfs_insert_empty_item(trans, uuid_root, path, &key,
117 sizeof(subid_le));
118 if (ret == 0) {
119 /* Add an item for the type for the first time */
120 eb = path->nodes[0];
121 slot = path->slots[0];
122 offset = btrfs_item_ptr_offset(eb, slot);
123 } else if (ret == -EEXIST) {
124 /*
125 * An item with that type already exists.
126 * Extend the item and store the new subid at the end.
127 */
128 btrfs_extend_item(trans, path, sizeof(subid_le));
129 eb = path->nodes[0];
130 slot = path->slots[0];
131 offset = btrfs_item_ptr_offset(eb, slot);
132 offset += btrfs_item_size(eb, slot) - sizeof(subid_le);
133 } else {
134 btrfs_warn(fs_info,
135 "insert uuid item failed %d (0x%016llx, 0x%016llx) type %u!",
136 ret, key.objectid, key.offset, type);
137 goto out;
138 }
139
140 ret = 0;
141 subid_le = cpu_to_le64(subid_cpu);
142 write_extent_buffer(eb, &subid_le, offset, sizeof(subid_le));
143 btrfs_mark_buffer_dirty(trans, eb);
144
145out:
146 btrfs_free_path(path);
147 return ret;
148}
149
150int btrfs_uuid_tree_remove(struct btrfs_trans_handle *trans, const u8 *uuid, u8 type,
151 u64 subid)
152{
153 struct btrfs_fs_info *fs_info = trans->fs_info;
154 struct btrfs_root *uuid_root = fs_info->uuid_root;
155 int ret;
156 struct btrfs_path *path = NULL;
157 struct btrfs_key key;
158 struct extent_buffer *eb;
159 int slot;
160 unsigned long offset;
161 u32 item_size;
162 unsigned long move_dst;
163 unsigned long move_src;
164 unsigned long move_len;
165
166 if (WARN_ON_ONCE(!uuid_root)) {
167 ret = -EINVAL;
168 goto out;
169 }
170
171 btrfs_uuid_to_key(uuid, type, &key);
172
173 path = btrfs_alloc_path();
174 if (!path) {
175 ret = -ENOMEM;
176 goto out;
177 }
178
179 ret = btrfs_search_slot(trans, uuid_root, &key, path, -1, 1);
180 if (ret < 0) {
181 btrfs_warn(fs_info, "error %d while searching for uuid item!",
182 ret);
183 goto out;
184 }
185 if (ret > 0) {
186 ret = -ENOENT;
187 goto out;
188 }
189
190 eb = path->nodes[0];
191 slot = path->slots[0];
192 offset = btrfs_item_ptr_offset(eb, slot);
193 item_size = btrfs_item_size(eb, slot);
194 if (!IS_ALIGNED(item_size, sizeof(u64))) {
195 btrfs_warn(fs_info, "uuid item with illegal size %lu!",
196 (unsigned long)item_size);
197 ret = -ENOENT;
198 goto out;
199 }
200 while (item_size) {
201 __le64 read_subid;
202
203 read_extent_buffer(eb, &read_subid, offset, sizeof(read_subid));
204 if (le64_to_cpu(read_subid) == subid)
205 break;
206 offset += sizeof(read_subid);
207 item_size -= sizeof(read_subid);
208 }
209
210 if (!item_size) {
211 ret = -ENOENT;
212 goto out;
213 }
214
215 item_size = btrfs_item_size(eb, slot);
216 if (item_size == sizeof(subid)) {
217 ret = btrfs_del_item(trans, uuid_root, path);
218 goto out;
219 }
220
221 move_dst = offset;
222 move_src = offset + sizeof(subid);
223 move_len = item_size - (move_src - btrfs_item_ptr_offset(eb, slot));
224 memmove_extent_buffer(eb, move_dst, move_src, move_len);
225 btrfs_truncate_item(trans, path, item_size - sizeof(subid), 1);
226
227out:
228 btrfs_free_path(path);
229 return ret;
230}
231
232static int btrfs_uuid_iter_rem(struct btrfs_root *uuid_root, u8 *uuid, u8 type,
233 u64 subid)
234{
235 struct btrfs_trans_handle *trans;
236 int ret;
237
238 /* 1 - for the uuid item */
239 trans = btrfs_start_transaction(uuid_root, 1);
240 if (IS_ERR(trans)) {
241 ret = PTR_ERR(trans);
242 goto out;
243 }
244
245 ret = btrfs_uuid_tree_remove(trans, uuid, type, subid);
246 btrfs_end_transaction(trans);
247
248out:
249 return ret;
250}
251
252/*
253 * Check if there's an matching subvolume for given UUID
254 *
255 * Return:
256 * 0 check succeeded, the entry is not outdated
257 * > 0 if the check failed, the caller should remove the entry
258 * < 0 if an error occurred
259 */
260static int btrfs_check_uuid_tree_entry(struct btrfs_fs_info *fs_info,
261 const u8 *uuid, u8 type, u64 subvolid)
262{
263 int ret = 0;
264 struct btrfs_root *subvol_root;
265
266 if (type != BTRFS_UUID_KEY_SUBVOL &&
267 type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
268 goto out;
269
270 subvol_root = btrfs_get_fs_root(fs_info, subvolid, true);
271 if (IS_ERR(subvol_root)) {
272 ret = PTR_ERR(subvol_root);
273 if (ret == -ENOENT)
274 ret = 1;
275 goto out;
276 }
277
278 switch (type) {
279 case BTRFS_UUID_KEY_SUBVOL:
280 if (memcmp(uuid, subvol_root->root_item.uuid, BTRFS_UUID_SIZE))
281 ret = 1;
282 break;
283 case BTRFS_UUID_KEY_RECEIVED_SUBVOL:
284 if (memcmp(uuid, subvol_root->root_item.received_uuid,
285 BTRFS_UUID_SIZE))
286 ret = 1;
287 break;
288 }
289 btrfs_put_root(subvol_root);
290out:
291 return ret;
292}
293
294int btrfs_uuid_tree_iterate(struct btrfs_fs_info *fs_info)
295{
296 struct btrfs_root *root = fs_info->uuid_root;
297 struct btrfs_key key;
298 struct btrfs_path *path;
299 int ret = 0;
300 struct extent_buffer *leaf;
301 int slot;
302 u32 item_size;
303 unsigned long offset;
304
305 path = btrfs_alloc_path();
306 if (!path) {
307 ret = -ENOMEM;
308 goto out;
309 }
310
311 key.objectid = 0;
312 key.type = 0;
313 key.offset = 0;
314
315again_search_slot:
316 ret = btrfs_search_forward(root, &key, path, BTRFS_OLDEST_GENERATION);
317 if (ret) {
318 if (ret > 0)
319 ret = 0;
320 goto out;
321 }
322
323 while (1) {
324 if (btrfs_fs_closing(fs_info)) {
325 ret = -EINTR;
326 goto out;
327 }
328 cond_resched();
329 leaf = path->nodes[0];
330 slot = path->slots[0];
331 btrfs_item_key_to_cpu(leaf, &key, slot);
332
333 if (key.type != BTRFS_UUID_KEY_SUBVOL &&
334 key.type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
335 goto skip;
336
337 offset = btrfs_item_ptr_offset(leaf, slot);
338 item_size = btrfs_item_size(leaf, slot);
339 if (!IS_ALIGNED(item_size, sizeof(u64))) {
340 btrfs_warn(fs_info,
341 "uuid item with illegal size %lu!",
342 (unsigned long)item_size);
343 goto skip;
344 }
345 while (item_size) {
346 u8 uuid[BTRFS_UUID_SIZE];
347 __le64 subid_le;
348 u64 subid_cpu;
349
350 put_unaligned_le64(key.objectid, uuid);
351 put_unaligned_le64(key.offset, uuid + sizeof(u64));
352 read_extent_buffer(leaf, &subid_le, offset,
353 sizeof(subid_le));
354 subid_cpu = le64_to_cpu(subid_le);
355 ret = btrfs_check_uuid_tree_entry(fs_info, uuid,
356 key.type, subid_cpu);
357 if (ret < 0)
358 goto out;
359 if (ret > 0) {
360 btrfs_release_path(path);
361 ret = btrfs_uuid_iter_rem(root, uuid, key.type,
362 subid_cpu);
363 if (ret == 0) {
364 /*
365 * this might look inefficient, but the
366 * justification is that it is an
367 * exception that check_func returns 1,
368 * and that in the regular case only one
369 * entry per UUID exists.
370 */
371 goto again_search_slot;
372 }
373 if (ret < 0 && ret != -ENOENT)
374 goto out;
375 key.offset++;
376 goto again_search_slot;
377 }
378 item_size -= sizeof(subid_le);
379 offset += sizeof(subid_le);
380 }
381
382skip:
383 ret = btrfs_next_item(root, path);
384 if (ret == 0)
385 continue;
386 else if (ret > 0)
387 ret = 0;
388 break;
389 }
390
391out:
392 btrfs_free_path(path);
393 return ret;
394}
395
396int btrfs_uuid_scan_kthread(void *data)
397{
398 struct btrfs_fs_info *fs_info = data;
399 struct btrfs_root *root = fs_info->tree_root;
400 struct btrfs_key key;
401 struct btrfs_path *path = NULL;
402 int ret = 0;
403 struct extent_buffer *eb;
404 int slot;
405 struct btrfs_root_item root_item;
406 u32 item_size;
407 struct btrfs_trans_handle *trans = NULL;
408 bool closing = false;
409
410 path = btrfs_alloc_path();
411 if (!path) {
412 ret = -ENOMEM;
413 goto out;
414 }
415
416 key.objectid = 0;
417 key.type = BTRFS_ROOT_ITEM_KEY;
418 key.offset = 0;
419
420 while (1) {
421 if (btrfs_fs_closing(fs_info)) {
422 closing = true;
423 break;
424 }
425 ret = btrfs_search_forward(root, &key, path,
426 BTRFS_OLDEST_GENERATION);
427 if (ret) {
428 if (ret > 0)
429 ret = 0;
430 break;
431 }
432
433 if (key.type != BTRFS_ROOT_ITEM_KEY ||
434 (key.objectid < BTRFS_FIRST_FREE_OBJECTID &&
435 key.objectid != BTRFS_FS_TREE_OBJECTID) ||
436 key.objectid > BTRFS_LAST_FREE_OBJECTID)
437 goto skip;
438
439 eb = path->nodes[0];
440 slot = path->slots[0];
441 item_size = btrfs_item_size(eb, slot);
442 if (item_size < sizeof(root_item))
443 goto skip;
444
445 read_extent_buffer(eb, &root_item,
446 btrfs_item_ptr_offset(eb, slot),
447 (int)sizeof(root_item));
448 if (btrfs_root_refs(&root_item) == 0)
449 goto skip;
450
451 if (!btrfs_is_empty_uuid(root_item.uuid) ||
452 !btrfs_is_empty_uuid(root_item.received_uuid)) {
453 if (trans)
454 goto update_tree;
455
456 btrfs_release_path(path);
457 /*
458 * 1 - subvol uuid item
459 * 1 - received_subvol uuid item
460 */
461 trans = btrfs_start_transaction(fs_info->uuid_root, 2);
462 if (IS_ERR(trans)) {
463 ret = PTR_ERR(trans);
464 break;
465 }
466 continue;
467 } else {
468 goto skip;
469 }
470update_tree:
471 btrfs_release_path(path);
472 if (!btrfs_is_empty_uuid(root_item.uuid)) {
473 ret = btrfs_uuid_tree_add(trans, root_item.uuid,
474 BTRFS_UUID_KEY_SUBVOL,
475 key.objectid);
476 if (ret < 0) {
477 btrfs_warn(fs_info, "uuid_tree_add failed %d",
478 ret);
479 break;
480 }
481 }
482
483 if (!btrfs_is_empty_uuid(root_item.received_uuid)) {
484 ret = btrfs_uuid_tree_add(trans,
485 root_item.received_uuid,
486 BTRFS_UUID_KEY_RECEIVED_SUBVOL,
487 key.objectid);
488 if (ret < 0) {
489 btrfs_warn(fs_info, "uuid_tree_add failed %d",
490 ret);
491 break;
492 }
493 }
494
495skip:
496 btrfs_release_path(path);
497 if (trans) {
498 ret = btrfs_end_transaction(trans);
499 trans = NULL;
500 if (ret)
501 break;
502 }
503
504 if (key.offset < (u64)-1) {
505 key.offset++;
506 } else if (key.type < BTRFS_ROOT_ITEM_KEY) {
507 key.offset = 0;
508 key.type = BTRFS_ROOT_ITEM_KEY;
509 } else if (key.objectid < (u64)-1) {
510 key.offset = 0;
511 key.type = BTRFS_ROOT_ITEM_KEY;
512 key.objectid++;
513 } else {
514 break;
515 }
516 cond_resched();
517 }
518
519out:
520 btrfs_free_path(path);
521 if (trans && !IS_ERR(trans))
522 btrfs_end_transaction(trans);
523 if (ret)
524 btrfs_warn(fs_info, "btrfs_uuid_scan_kthread failed %d", ret);
525 else if (!closing)
526 set_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags);
527 up(&fs_info->uuid_tree_rescan_sem);
528 return 0;
529}
530
531int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info)
532{
533 struct btrfs_trans_handle *trans;
534 struct btrfs_root *tree_root = fs_info->tree_root;
535 struct btrfs_root *uuid_root;
536 struct task_struct *task;
537 int ret;
538
539 /*
540 * 1 - root node
541 * 1 - root item
542 */
543 trans = btrfs_start_transaction(tree_root, 2);
544 if (IS_ERR(trans))
545 return PTR_ERR(trans);
546
547 uuid_root = btrfs_create_tree(trans, BTRFS_UUID_TREE_OBJECTID);
548 if (IS_ERR(uuid_root)) {
549 ret = PTR_ERR(uuid_root);
550 btrfs_abort_transaction(trans, ret);
551 btrfs_end_transaction(trans);
552 return ret;
553 }
554
555 fs_info->uuid_root = uuid_root;
556
557 ret = btrfs_commit_transaction(trans);
558 if (ret)
559 return ret;
560
561 down(&fs_info->uuid_tree_rescan_sem);
562 task = kthread_run(btrfs_uuid_scan_kthread, fs_info, "btrfs-uuid");
563 if (IS_ERR(task)) {
564 /* fs_info->update_uuid_tree_gen remains 0 in all error case */
565 btrfs_warn(fs_info, "failed to start uuid_scan task");
566 up(&fs_info->uuid_tree_rescan_sem);
567 return PTR_ERR(task);
568 }
569
570 return 0;
571}
1/*
2 * Copyright (C) STRATO AG 2013. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18#include <linux/uuid.h>
19#include <asm/unaligned.h>
20#include "ctree.h"
21#include "transaction.h"
22#include "disk-io.h"
23#include "print-tree.h"
24
25
26static void btrfs_uuid_to_key(u8 *uuid, u8 type, struct btrfs_key *key)
27{
28 key->type = type;
29 key->objectid = get_unaligned_le64(uuid);
30 key->offset = get_unaligned_le64(uuid + sizeof(u64));
31}
32
33/* return -ENOENT for !found, < 0 for errors, or 0 if an item was found */
34static int btrfs_uuid_tree_lookup(struct btrfs_root *uuid_root, u8 *uuid,
35 u8 type, u64 subid)
36{
37 int ret;
38 struct btrfs_path *path = NULL;
39 struct extent_buffer *eb;
40 int slot;
41 u32 item_size;
42 unsigned long offset;
43 struct btrfs_key key;
44
45 if (WARN_ON_ONCE(!uuid_root)) {
46 ret = -ENOENT;
47 goto out;
48 }
49
50 path = btrfs_alloc_path();
51 if (!path) {
52 ret = -ENOMEM;
53 goto out;
54 }
55
56 btrfs_uuid_to_key(uuid, type, &key);
57 ret = btrfs_search_slot(NULL, uuid_root, &key, path, 0, 0);
58 if (ret < 0) {
59 goto out;
60 } else if (ret > 0) {
61 ret = -ENOENT;
62 goto out;
63 }
64
65 eb = path->nodes[0];
66 slot = path->slots[0];
67 item_size = btrfs_item_size_nr(eb, slot);
68 offset = btrfs_item_ptr_offset(eb, slot);
69 ret = -ENOENT;
70
71 if (!IS_ALIGNED(item_size, sizeof(u64))) {
72 btrfs_warn(uuid_root->fs_info, "uuid item with illegal size %lu!",
73 (unsigned long)item_size);
74 goto out;
75 }
76 while (item_size) {
77 __le64 data;
78
79 read_extent_buffer(eb, &data, offset, sizeof(data));
80 if (le64_to_cpu(data) == subid) {
81 ret = 0;
82 break;
83 }
84 offset += sizeof(data);
85 item_size -= sizeof(data);
86 }
87
88out:
89 btrfs_free_path(path);
90 return ret;
91}
92
93int btrfs_uuid_tree_add(struct btrfs_trans_handle *trans,
94 struct btrfs_root *uuid_root, u8 *uuid, u8 type,
95 u64 subid_cpu)
96{
97 int ret;
98 struct btrfs_path *path = NULL;
99 struct btrfs_key key;
100 struct extent_buffer *eb;
101 int slot;
102 unsigned long offset;
103 __le64 subid_le;
104
105 ret = btrfs_uuid_tree_lookup(uuid_root, uuid, type, subid_cpu);
106 if (ret != -ENOENT)
107 return ret;
108
109 if (WARN_ON_ONCE(!uuid_root)) {
110 ret = -EINVAL;
111 goto out;
112 }
113
114 btrfs_uuid_to_key(uuid, type, &key);
115
116 path = btrfs_alloc_path();
117 if (!path) {
118 ret = -ENOMEM;
119 goto out;
120 }
121
122 ret = btrfs_insert_empty_item(trans, uuid_root, path, &key,
123 sizeof(subid_le));
124 if (ret >= 0) {
125 /* Add an item for the type for the first time */
126 eb = path->nodes[0];
127 slot = path->slots[0];
128 offset = btrfs_item_ptr_offset(eb, slot);
129 } else if (ret == -EEXIST) {
130 /*
131 * An item with that type already exists.
132 * Extend the item and store the new subid at the end.
133 */
134 btrfs_extend_item(uuid_root, path, sizeof(subid_le));
135 eb = path->nodes[0];
136 slot = path->slots[0];
137 offset = btrfs_item_ptr_offset(eb, slot);
138 offset += btrfs_item_size_nr(eb, slot) - sizeof(subid_le);
139 } else if (ret < 0) {
140 btrfs_warn(uuid_root->fs_info, "insert uuid item failed %d "
141 "(0x%016llx, 0x%016llx) type %u!",
142 ret, (unsigned long long)key.objectid,
143 (unsigned long long)key.offset, type);
144 goto out;
145 }
146
147 ret = 0;
148 subid_le = cpu_to_le64(subid_cpu);
149 write_extent_buffer(eb, &subid_le, offset, sizeof(subid_le));
150 btrfs_mark_buffer_dirty(eb);
151
152out:
153 btrfs_free_path(path);
154 return ret;
155}
156
157int btrfs_uuid_tree_rem(struct btrfs_trans_handle *trans,
158 struct btrfs_root *uuid_root, u8 *uuid, u8 type,
159 u64 subid)
160{
161 int ret;
162 struct btrfs_path *path = NULL;
163 struct btrfs_key key;
164 struct extent_buffer *eb;
165 int slot;
166 unsigned long offset;
167 u32 item_size;
168 unsigned long move_dst;
169 unsigned long move_src;
170 unsigned long move_len;
171
172 if (WARN_ON_ONCE(!uuid_root)) {
173 ret = -EINVAL;
174 goto out;
175 }
176
177 btrfs_uuid_to_key(uuid, type, &key);
178
179 path = btrfs_alloc_path();
180 if (!path) {
181 ret = -ENOMEM;
182 goto out;
183 }
184
185 ret = btrfs_search_slot(trans, uuid_root, &key, path, -1, 1);
186 if (ret < 0) {
187 btrfs_warn(uuid_root->fs_info, "error %d while searching for uuid item!",
188 ret);
189 goto out;
190 }
191 if (ret > 0) {
192 ret = -ENOENT;
193 goto out;
194 }
195
196 eb = path->nodes[0];
197 slot = path->slots[0];
198 offset = btrfs_item_ptr_offset(eb, slot);
199 item_size = btrfs_item_size_nr(eb, slot);
200 if (!IS_ALIGNED(item_size, sizeof(u64))) {
201 btrfs_warn(uuid_root->fs_info, "uuid item with illegal size %lu!",
202 (unsigned long)item_size);
203 ret = -ENOENT;
204 goto out;
205 }
206 while (item_size) {
207 __le64 read_subid;
208
209 read_extent_buffer(eb, &read_subid, offset, sizeof(read_subid));
210 if (le64_to_cpu(read_subid) == subid)
211 break;
212 offset += sizeof(read_subid);
213 item_size -= sizeof(read_subid);
214 }
215
216 if (!item_size) {
217 ret = -ENOENT;
218 goto out;
219 }
220
221 item_size = btrfs_item_size_nr(eb, slot);
222 if (item_size == sizeof(subid)) {
223 ret = btrfs_del_item(trans, uuid_root, path);
224 goto out;
225 }
226
227 move_dst = offset;
228 move_src = offset + sizeof(subid);
229 move_len = item_size - (move_src - btrfs_item_ptr_offset(eb, slot));
230 memmove_extent_buffer(eb, move_dst, move_src, move_len);
231 btrfs_truncate_item(uuid_root, path, item_size - sizeof(subid), 1);
232
233out:
234 btrfs_free_path(path);
235 return ret;
236}
237
238static int btrfs_uuid_iter_rem(struct btrfs_root *uuid_root, u8 *uuid, u8 type,
239 u64 subid)
240{
241 struct btrfs_trans_handle *trans;
242 int ret;
243
244 /* 1 - for the uuid item */
245 trans = btrfs_start_transaction(uuid_root, 1);
246 if (IS_ERR(trans)) {
247 ret = PTR_ERR(trans);
248 goto out;
249 }
250
251 ret = btrfs_uuid_tree_rem(trans, uuid_root, uuid, type, subid);
252 btrfs_end_transaction(trans, uuid_root);
253
254out:
255 return ret;
256}
257
258int btrfs_uuid_tree_iterate(struct btrfs_fs_info *fs_info,
259 int (*check_func)(struct btrfs_fs_info *, u8 *, u8,
260 u64))
261{
262 struct btrfs_root *root = fs_info->uuid_root;
263 struct btrfs_key key;
264 struct btrfs_path *path;
265 int ret = 0;
266 struct extent_buffer *leaf;
267 int slot;
268 u32 item_size;
269 unsigned long offset;
270
271 path = btrfs_alloc_path();
272 if (!path) {
273 ret = -ENOMEM;
274 goto out;
275 }
276
277 key.objectid = 0;
278 key.type = 0;
279 key.offset = 0;
280
281again_search_slot:
282 path->keep_locks = 1;
283 ret = btrfs_search_forward(root, &key, path, 0);
284 if (ret) {
285 if (ret > 0)
286 ret = 0;
287 goto out;
288 }
289
290 while (1) {
291 cond_resched();
292 leaf = path->nodes[0];
293 slot = path->slots[0];
294 btrfs_item_key_to_cpu(leaf, &key, slot);
295
296 if (key.type != BTRFS_UUID_KEY_SUBVOL &&
297 key.type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
298 goto skip;
299
300 offset = btrfs_item_ptr_offset(leaf, slot);
301 item_size = btrfs_item_size_nr(leaf, slot);
302 if (!IS_ALIGNED(item_size, sizeof(u64))) {
303 btrfs_warn(fs_info, "uuid item with illegal size %lu!",
304 (unsigned long)item_size);
305 goto skip;
306 }
307 while (item_size) {
308 u8 uuid[BTRFS_UUID_SIZE];
309 __le64 subid_le;
310 u64 subid_cpu;
311
312 put_unaligned_le64(key.objectid, uuid);
313 put_unaligned_le64(key.offset, uuid + sizeof(u64));
314 read_extent_buffer(leaf, &subid_le, offset,
315 sizeof(subid_le));
316 subid_cpu = le64_to_cpu(subid_le);
317 ret = check_func(fs_info, uuid, key.type, subid_cpu);
318 if (ret < 0)
319 goto out;
320 if (ret > 0) {
321 btrfs_release_path(path);
322 ret = btrfs_uuid_iter_rem(root, uuid, key.type,
323 subid_cpu);
324 if (ret == 0) {
325 /*
326 * this might look inefficient, but the
327 * justification is that it is an
328 * exception that check_func returns 1,
329 * and that in the regular case only one
330 * entry per UUID exists.
331 */
332 goto again_search_slot;
333 }
334 if (ret < 0 && ret != -ENOENT)
335 goto out;
336 }
337 item_size -= sizeof(subid_le);
338 offset += sizeof(subid_le);
339 }
340
341skip:
342 ret = btrfs_next_item(root, path);
343 if (ret == 0)
344 continue;
345 else if (ret > 0)
346 ret = 0;
347 break;
348 }
349
350out:
351 btrfs_free_path(path);
352 if (ret)
353 btrfs_warn(fs_info, "btrfs_uuid_tree_iterate failed %d", ret);
354 return 0;
355}