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
btrfs_uuid_to_key(const u8 * uuid,u8 type,struct btrfs_key * key)18 static 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 */
btrfs_uuid_tree_lookup(struct btrfs_root * uuid_root,const u8 * uuid,u8 type,u64 subid)26 static 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
81 out:
82 btrfs_free_path(path);
83 return ret;
84 }
85
btrfs_uuid_tree_add(struct btrfs_trans_handle * trans,const u8 * uuid,u8 type,u64 subid_cpu)86 int 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 out:
144 btrfs_free_path(path);
145 return ret;
146 }
147
btrfs_uuid_tree_remove(struct btrfs_trans_handle * trans,const u8 * uuid,u8 type,u64 subid)148 int btrfs_uuid_tree_remove(struct btrfs_trans_handle *trans, const 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
225 out:
226 btrfs_free_path(path);
227 return ret;
228 }
229
btrfs_uuid_iter_rem(struct btrfs_root * uuid_root,u8 * uuid,u8 type,u64 subid)230 static 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
246 out:
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 */
btrfs_check_uuid_tree_entry(struct btrfs_fs_info * fs_info,const u8 * uuid,u8 type,u64 subvolid)258 static int btrfs_check_uuid_tree_entry(struct btrfs_fs_info *fs_info,
259 const 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);
288 out:
289 return ret;
290 }
291
btrfs_uuid_tree_iterate(struct btrfs_fs_info * fs_info)292 int 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
313 again_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
380 skip:
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
389 out:
390 btrfs_free_path(path);
391 return ret;
392 }
393
btrfs_uuid_scan_kthread(void * data)394 int btrfs_uuid_scan_kthread(void *data)
395 {
396 struct btrfs_fs_info *fs_info = data;
397 struct btrfs_root *root = fs_info->tree_root;
398 struct btrfs_key key;
399 struct btrfs_path *path = NULL;
400 int ret = 0;
401 struct extent_buffer *eb;
402 int slot;
403 struct btrfs_root_item root_item;
404 u32 item_size;
405 struct btrfs_trans_handle *trans = NULL;
406 bool closing = false;
407
408 path = btrfs_alloc_path();
409 if (!path) {
410 ret = -ENOMEM;
411 goto out;
412 }
413
414 key.objectid = 0;
415 key.type = BTRFS_ROOT_ITEM_KEY;
416 key.offset = 0;
417
418 while (1) {
419 if (btrfs_fs_closing(fs_info)) {
420 closing = true;
421 break;
422 }
423 ret = btrfs_search_forward(root, &key, path,
424 BTRFS_OLDEST_GENERATION);
425 if (ret) {
426 if (ret > 0)
427 ret = 0;
428 break;
429 }
430
431 if (key.type != BTRFS_ROOT_ITEM_KEY ||
432 (key.objectid < BTRFS_FIRST_FREE_OBJECTID &&
433 key.objectid != BTRFS_FS_TREE_OBJECTID) ||
434 key.objectid > BTRFS_LAST_FREE_OBJECTID)
435 goto skip;
436
437 eb = path->nodes[0];
438 slot = path->slots[0];
439 item_size = btrfs_item_size(eb, slot);
440 if (item_size < sizeof(root_item))
441 goto skip;
442
443 read_extent_buffer(eb, &root_item,
444 btrfs_item_ptr_offset(eb, slot),
445 (int)sizeof(root_item));
446 if (btrfs_root_refs(&root_item) == 0)
447 goto skip;
448
449 if (!btrfs_is_empty_uuid(root_item.uuid) ||
450 !btrfs_is_empty_uuid(root_item.received_uuid)) {
451 if (trans)
452 goto update_tree;
453
454 btrfs_release_path(path);
455 /*
456 * 1 - subvol uuid item
457 * 1 - received_subvol uuid item
458 */
459 trans = btrfs_start_transaction(fs_info->uuid_root, 2);
460 if (IS_ERR(trans)) {
461 ret = PTR_ERR(trans);
462 break;
463 }
464 continue;
465 } else {
466 goto skip;
467 }
468 update_tree:
469 btrfs_release_path(path);
470 if (!btrfs_is_empty_uuid(root_item.uuid)) {
471 ret = btrfs_uuid_tree_add(trans, root_item.uuid,
472 BTRFS_UUID_KEY_SUBVOL,
473 key.objectid);
474 if (ret < 0) {
475 btrfs_warn(fs_info, "uuid_tree_add failed %d",
476 ret);
477 break;
478 }
479 }
480
481 if (!btrfs_is_empty_uuid(root_item.received_uuid)) {
482 ret = btrfs_uuid_tree_add(trans,
483 root_item.received_uuid,
484 BTRFS_UUID_KEY_RECEIVED_SUBVOL,
485 key.objectid);
486 if (ret < 0) {
487 btrfs_warn(fs_info, "uuid_tree_add failed %d",
488 ret);
489 break;
490 }
491 }
492
493 skip:
494 btrfs_release_path(path);
495 if (trans) {
496 ret = btrfs_end_transaction(trans);
497 trans = NULL;
498 if (ret)
499 break;
500 }
501
502 if (key.offset < (u64)-1) {
503 key.offset++;
504 } else if (key.type < BTRFS_ROOT_ITEM_KEY) {
505 key.offset = 0;
506 key.type = BTRFS_ROOT_ITEM_KEY;
507 } else if (key.objectid < (u64)-1) {
508 key.offset = 0;
509 key.type = BTRFS_ROOT_ITEM_KEY;
510 key.objectid++;
511 } else {
512 break;
513 }
514 cond_resched();
515 }
516
517 out:
518 btrfs_free_path(path);
519 if (trans && !IS_ERR(trans))
520 btrfs_end_transaction(trans);
521 if (ret)
522 btrfs_warn(fs_info, "btrfs_uuid_scan_kthread failed %d", ret);
523 else if (!closing)
524 set_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags);
525 up(&fs_info->uuid_tree_rescan_sem);
526 return 0;
527 }
528
btrfs_create_uuid_tree(struct btrfs_fs_info * fs_info)529 int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info)
530 {
531 struct btrfs_trans_handle *trans;
532 struct btrfs_root *tree_root = fs_info->tree_root;
533 struct btrfs_root *uuid_root;
534 struct task_struct *task;
535 int ret;
536
537 /*
538 * 1 - root node
539 * 1 - root item
540 */
541 trans = btrfs_start_transaction(tree_root, 2);
542 if (IS_ERR(trans))
543 return PTR_ERR(trans);
544
545 uuid_root = btrfs_create_tree(trans, BTRFS_UUID_TREE_OBJECTID);
546 if (IS_ERR(uuid_root)) {
547 ret = PTR_ERR(uuid_root);
548 btrfs_abort_transaction(trans, ret);
549 btrfs_end_transaction(trans);
550 return ret;
551 }
552
553 fs_info->uuid_root = uuid_root;
554
555 ret = btrfs_commit_transaction(trans);
556 if (ret)
557 return ret;
558
559 down(&fs_info->uuid_tree_rescan_sem);
560 task = kthread_run(btrfs_uuid_scan_kthread, fs_info, "btrfs-uuid");
561 if (IS_ERR(task)) {
562 /* fs_info->update_uuid_tree_gen remains 0 in all error case */
563 btrfs_warn(fs_info, "failed to start uuid_scan task");
564 up(&fs_info->uuid_tree_rescan_sem);
565 return PTR_ERR(task);
566 }
567
568 return 0;
569 }
570