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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// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) STRATO AG 2013. All rights reserved.
4 */
5
6#include <linux/uuid.h>
7#include <asm/unaligned.h>
8#include "messages.h"
9#include "ctree.h"
10#include "transaction.h"
11#include "disk-io.h"
12#include "fs.h"
13#include "accessors.h"
14#include "uuid-tree.h"
15
16static void btrfs_uuid_to_key(u8 *uuid, u8 type, struct btrfs_key *key)
17{
18 key->type = type;
19 key->objectid = get_unaligned_le64(uuid);
20 key->offset = get_unaligned_le64(uuid + sizeof(u64));
21}
22
23/* return -ENOENT for !found, < 0 for errors, or 0 if an item was found */
24static int btrfs_uuid_tree_lookup(struct btrfs_root *uuid_root, u8 *uuid,
25 u8 type, u64 subid)
26{
27 int ret;
28 struct btrfs_path *path = NULL;
29 struct extent_buffer *eb;
30 int slot;
31 u32 item_size;
32 unsigned long offset;
33 struct btrfs_key key;
34
35 if (WARN_ON_ONCE(!uuid_root)) {
36 ret = -ENOENT;
37 goto out;
38 }
39
40 path = btrfs_alloc_path();
41 if (!path) {
42 ret = -ENOMEM;
43 goto out;
44 }
45
46 btrfs_uuid_to_key(uuid, type, &key);
47 ret = btrfs_search_slot(NULL, uuid_root, &key, path, 0, 0);
48 if (ret < 0) {
49 goto out;
50 } else if (ret > 0) {
51 ret = -ENOENT;
52 goto out;
53 }
54
55 eb = path->nodes[0];
56 slot = path->slots[0];
57 item_size = btrfs_item_size(eb, slot);
58 offset = btrfs_item_ptr_offset(eb, slot);
59 ret = -ENOENT;
60
61 if (!IS_ALIGNED(item_size, sizeof(u64))) {
62 btrfs_warn(uuid_root->fs_info,
63 "uuid item with illegal size %lu!",
64 (unsigned long)item_size);
65 goto out;
66 }
67 while (item_size) {
68 __le64 data;
69
70 read_extent_buffer(eb, &data, offset, sizeof(data));
71 if (le64_to_cpu(data) == subid) {
72 ret = 0;
73 break;
74 }
75 offset += sizeof(data);
76 item_size -= sizeof(data);
77 }
78
79out:
80 btrfs_free_path(path);
81 return ret;
82}
83
84int btrfs_uuid_tree_add(struct btrfs_trans_handle *trans, u8 *uuid, u8 type,
85 u64 subid_cpu)
86{
87 struct btrfs_fs_info *fs_info = trans->fs_info;
88 struct btrfs_root *uuid_root = fs_info->uuid_root;
89 int ret;
90 struct btrfs_path *path = NULL;
91 struct btrfs_key key;
92 struct extent_buffer *eb;
93 int slot;
94 unsigned long offset;
95 __le64 subid_le;
96
97 ret = btrfs_uuid_tree_lookup(uuid_root, uuid, type, subid_cpu);
98 if (ret != -ENOENT)
99 return ret;
100
101 if (WARN_ON_ONCE(!uuid_root)) {
102 ret = -EINVAL;
103 goto out;
104 }
105
106 btrfs_uuid_to_key(uuid, type, &key);
107
108 path = btrfs_alloc_path();
109 if (!path) {
110 ret = -ENOMEM;
111 goto out;
112 }
113
114 ret = btrfs_insert_empty_item(trans, uuid_root, path, &key,
115 sizeof(subid_le));
116 if (ret == 0) {
117 /* Add an item for the type for the first time */
118 eb = path->nodes[0];
119 slot = path->slots[0];
120 offset = btrfs_item_ptr_offset(eb, slot);
121 } else if (ret == -EEXIST) {
122 /*
123 * An item with that type already exists.
124 * Extend the item and store the new subid at the end.
125 */
126 btrfs_extend_item(trans, path, sizeof(subid_le));
127 eb = path->nodes[0];
128 slot = path->slots[0];
129 offset = btrfs_item_ptr_offset(eb, slot);
130 offset += btrfs_item_size(eb, slot) - sizeof(subid_le);
131 } else {
132 btrfs_warn(fs_info,
133 "insert uuid item failed %d (0x%016llx, 0x%016llx) type %u!",
134 ret, key.objectid, key.offset, type);
135 goto out;
136 }
137
138 ret = 0;
139 subid_le = cpu_to_le64(subid_cpu);
140 write_extent_buffer(eb, &subid_le, offset, sizeof(subid_le));
141 btrfs_mark_buffer_dirty(trans, eb);
142
143out:
144 btrfs_free_path(path);
145 return ret;
146}
147
148int btrfs_uuid_tree_remove(struct btrfs_trans_handle *trans, u8 *uuid, u8 type,
149 u64 subid)
150{
151 struct btrfs_fs_info *fs_info = trans->fs_info;
152 struct btrfs_root *uuid_root = fs_info->uuid_root;
153 int ret;
154 struct btrfs_path *path = NULL;
155 struct btrfs_key key;
156 struct extent_buffer *eb;
157 int slot;
158 unsigned long offset;
159 u32 item_size;
160 unsigned long move_dst;
161 unsigned long move_src;
162 unsigned long move_len;
163
164 if (WARN_ON_ONCE(!uuid_root)) {
165 ret = -EINVAL;
166 goto out;
167 }
168
169 btrfs_uuid_to_key(uuid, type, &key);
170
171 path = btrfs_alloc_path();
172 if (!path) {
173 ret = -ENOMEM;
174 goto out;
175 }
176
177 ret = btrfs_search_slot(trans, uuid_root, &key, path, -1, 1);
178 if (ret < 0) {
179 btrfs_warn(fs_info, "error %d while searching for uuid item!",
180 ret);
181 goto out;
182 }
183 if (ret > 0) {
184 ret = -ENOENT;
185 goto out;
186 }
187
188 eb = path->nodes[0];
189 slot = path->slots[0];
190 offset = btrfs_item_ptr_offset(eb, slot);
191 item_size = btrfs_item_size(eb, slot);
192 if (!IS_ALIGNED(item_size, sizeof(u64))) {
193 btrfs_warn(fs_info, "uuid item with illegal size %lu!",
194 (unsigned long)item_size);
195 ret = -ENOENT;
196 goto out;
197 }
198 while (item_size) {
199 __le64 read_subid;
200
201 read_extent_buffer(eb, &read_subid, offset, sizeof(read_subid));
202 if (le64_to_cpu(read_subid) == subid)
203 break;
204 offset += sizeof(read_subid);
205 item_size -= sizeof(read_subid);
206 }
207
208 if (!item_size) {
209 ret = -ENOENT;
210 goto out;
211 }
212
213 item_size = btrfs_item_size(eb, slot);
214 if (item_size == sizeof(subid)) {
215 ret = btrfs_del_item(trans, uuid_root, path);
216 goto out;
217 }
218
219 move_dst = offset;
220 move_src = offset + sizeof(subid);
221 move_len = item_size - (move_src - btrfs_item_ptr_offset(eb, slot));
222 memmove_extent_buffer(eb, move_dst, move_src, move_len);
223 btrfs_truncate_item(trans, path, item_size - sizeof(subid), 1);
224
225out:
226 btrfs_free_path(path);
227 return ret;
228}
229
230static int btrfs_uuid_iter_rem(struct btrfs_root *uuid_root, u8 *uuid, u8 type,
231 u64 subid)
232{
233 struct btrfs_trans_handle *trans;
234 int ret;
235
236 /* 1 - for the uuid item */
237 trans = btrfs_start_transaction(uuid_root, 1);
238 if (IS_ERR(trans)) {
239 ret = PTR_ERR(trans);
240 goto out;
241 }
242
243 ret = btrfs_uuid_tree_remove(trans, uuid, type, subid);
244 btrfs_end_transaction(trans);
245
246out:
247 return ret;
248}
249
250/*
251 * Check if there's an matching subvolume for given UUID
252 *
253 * Return:
254 * 0 check succeeded, the entry is not outdated
255 * > 0 if the check failed, the caller should remove the entry
256 * < 0 if an error occurred
257 */
258static int btrfs_check_uuid_tree_entry(struct btrfs_fs_info *fs_info,
259 u8 *uuid, u8 type, u64 subvolid)
260{
261 int ret = 0;
262 struct btrfs_root *subvol_root;
263
264 if (type != BTRFS_UUID_KEY_SUBVOL &&
265 type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
266 goto out;
267
268 subvol_root = btrfs_get_fs_root(fs_info, subvolid, true);
269 if (IS_ERR(subvol_root)) {
270 ret = PTR_ERR(subvol_root);
271 if (ret == -ENOENT)
272 ret = 1;
273 goto out;
274 }
275
276 switch (type) {
277 case BTRFS_UUID_KEY_SUBVOL:
278 if (memcmp(uuid, subvol_root->root_item.uuid, BTRFS_UUID_SIZE))
279 ret = 1;
280 break;
281 case BTRFS_UUID_KEY_RECEIVED_SUBVOL:
282 if (memcmp(uuid, subvol_root->root_item.received_uuid,
283 BTRFS_UUID_SIZE))
284 ret = 1;
285 break;
286 }
287 btrfs_put_root(subvol_root);
288out:
289 return ret;
290}
291
292int btrfs_uuid_tree_iterate(struct btrfs_fs_info *fs_info)
293{
294 struct btrfs_root *root = fs_info->uuid_root;
295 struct btrfs_key key;
296 struct btrfs_path *path;
297 int ret = 0;
298 struct extent_buffer *leaf;
299 int slot;
300 u32 item_size;
301 unsigned long offset;
302
303 path = btrfs_alloc_path();
304 if (!path) {
305 ret = -ENOMEM;
306 goto out;
307 }
308
309 key.objectid = 0;
310 key.type = 0;
311 key.offset = 0;
312
313again_search_slot:
314 ret = btrfs_search_forward(root, &key, path, BTRFS_OLDEST_GENERATION);
315 if (ret) {
316 if (ret > 0)
317 ret = 0;
318 goto out;
319 }
320
321 while (1) {
322 if (btrfs_fs_closing(fs_info)) {
323 ret = -EINTR;
324 goto out;
325 }
326 cond_resched();
327 leaf = path->nodes[0];
328 slot = path->slots[0];
329 btrfs_item_key_to_cpu(leaf, &key, slot);
330
331 if (key.type != BTRFS_UUID_KEY_SUBVOL &&
332 key.type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
333 goto skip;
334
335 offset = btrfs_item_ptr_offset(leaf, slot);
336 item_size = btrfs_item_size(leaf, slot);
337 if (!IS_ALIGNED(item_size, sizeof(u64))) {
338 btrfs_warn(fs_info,
339 "uuid item with illegal size %lu!",
340 (unsigned long)item_size);
341 goto skip;
342 }
343 while (item_size) {
344 u8 uuid[BTRFS_UUID_SIZE];
345 __le64 subid_le;
346 u64 subid_cpu;
347
348 put_unaligned_le64(key.objectid, uuid);
349 put_unaligned_le64(key.offset, uuid + sizeof(u64));
350 read_extent_buffer(leaf, &subid_le, offset,
351 sizeof(subid_le));
352 subid_cpu = le64_to_cpu(subid_le);
353 ret = btrfs_check_uuid_tree_entry(fs_info, uuid,
354 key.type, subid_cpu);
355 if (ret < 0)
356 goto out;
357 if (ret > 0) {
358 btrfs_release_path(path);
359 ret = btrfs_uuid_iter_rem(root, uuid, key.type,
360 subid_cpu);
361 if (ret == 0) {
362 /*
363 * this might look inefficient, but the
364 * justification is that it is an
365 * exception that check_func returns 1,
366 * and that in the regular case only one
367 * entry per UUID exists.
368 */
369 goto again_search_slot;
370 }
371 if (ret < 0 && ret != -ENOENT)
372 goto out;
373 key.offset++;
374 goto again_search_slot;
375 }
376 item_size -= sizeof(subid_le);
377 offset += sizeof(subid_le);
378 }
379
380skip:
381 ret = btrfs_next_item(root, path);
382 if (ret == 0)
383 continue;
384 else if (ret > 0)
385 ret = 0;
386 break;
387 }
388
389out:
390 btrfs_free_path(path);
391 return ret;
392}