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 btrfs_mark_buffer_dirty(trans, eb);
144
145 out:
146 btrfs_free_path(path);
147 return ret;
148 }
149
btrfs_uuid_tree_remove(struct btrfs_trans_handle * trans,const u8 * uuid,u8 type,u64 subid)150 int 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
227 out:
228 btrfs_free_path(path);
229 return ret;
230 }
231
btrfs_uuid_iter_rem(struct btrfs_root * uuid_root,u8 * uuid,u8 type,u64 subid)232 static 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
248 out:
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 */
btrfs_check_uuid_tree_entry(struct btrfs_fs_info * fs_info,const u8 * uuid,u8 type,u64 subvolid)260 static 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);
290 out:
291 return ret;
292 }
293
btrfs_uuid_tree_iterate(struct btrfs_fs_info * fs_info)294 int 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
315 again_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
382 skip:
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
391 out:
392 btrfs_free_path(path);
393 return ret;
394 }
395
btrfs_uuid_scan_kthread(void * data)396 int 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 }
470 update_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
495 skip:
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
519 out:
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
btrfs_create_uuid_tree(struct btrfs_fs_info * fs_info)531 int 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 }
572