Line data Source code
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 :
19 : #include <linux/err.h>
20 : #include <linux/uuid.h>
21 : #include "ctree.h"
22 : #include "transaction.h"
23 : #include "disk-io.h"
24 : #include "print-tree.h"
25 :
26 : /*
27 : * Read a root item from the tree. In case we detect a root item smaller then
28 : * sizeof(root_item), we know it's an old version of the root structure and
29 : * initialize all new fields to zero. The same happens if we detect mismatching
30 : * generation numbers as then we know the root was once mounted with an older
31 : * kernel that was not aware of the root item structure change.
32 : */
33 1915 : static void btrfs_read_root_item(struct extent_buffer *eb, int slot,
34 : struct btrfs_root_item *item)
35 : {
36 : uuid_le uuid;
37 : int len;
38 : int need_reset = 0;
39 :
40 1915 : len = btrfs_item_size_nr(eb, slot);
41 3830 : read_extent_buffer(eb, item, btrfs_item_ptr_offset(eb, slot),
42 1915 : min_t(int, len, (int)sizeof(*item)));
43 1915 : if (len < sizeof(*item))
44 : need_reset = 1;
45 3830 : if (!need_reset && btrfs_root_generation(item)
46 : != btrfs_root_generation_v2(item)) {
47 0 : if (btrfs_root_generation_v2(item) != 0) {
48 0 : printk(KERN_WARNING "BTRFS: mismatching "
49 : "generation and generation_v2 "
50 : "found in root item. This root "
51 : "was probably mounted with an "
52 : "older kernel. Resetting all "
53 : "new fields.\n");
54 : }
55 : need_reset = 1;
56 : }
57 1915 : if (need_reset) {
58 0 : memset(&item->generation_v2, 0,
59 : sizeof(*item) - offsetof(struct btrfs_root_item,
60 : generation_v2));
61 :
62 0 : uuid_le_gen(&uuid);
63 0 : memcpy(item->uuid, uuid.b, BTRFS_UUID_SIZE);
64 : }
65 1915 : }
66 :
67 : /*
68 : * btrfs_find_root - lookup the root by the key.
69 : * root: the root of the root tree
70 : * search_key: the key to search
71 : * path: the path we search
72 : * root_item: the root item of the tree we look for
73 : * root_key: the reak key of the tree we look for
74 : *
75 : * If ->offset of 'seach_key' is -1ULL, it means we are not sure the offset
76 : * of the search key, just lookup the root with the highest offset for a
77 : * given objectid.
78 : *
79 : * If we find something return 0, otherwise > 0, < 0 on error.
80 : */
81 2243 : int btrfs_find_root(struct btrfs_root *root, struct btrfs_key *search_key,
82 : struct btrfs_path *path, struct btrfs_root_item *root_item,
83 : struct btrfs_key *root_key)
84 : {
85 : struct btrfs_key found_key;
86 : struct extent_buffer *l;
87 : int ret;
88 : int slot;
89 :
90 2243 : ret = btrfs_search_slot(NULL, root, search_key, path, 0, 0);
91 2243 : if (ret < 0)
92 : return ret;
93 :
94 2243 : if (search_key->offset != -1ULL) { /* the search key is exact */
95 1779 : if (ret > 0)
96 : goto out;
97 : } else {
98 464 : BUG_ON(ret == 0); /* Logical error */
99 464 : if (path->slots[0] == 0)
100 : goto out;
101 464 : path->slots[0]--;
102 : ret = 0;
103 : }
104 :
105 1915 : l = path->nodes[0];
106 1915 : slot = path->slots[0];
107 :
108 1915 : btrfs_item_key_to_cpu(l, &found_key, slot);
109 3830 : if (found_key.objectid != search_key->objectid ||
110 1915 : found_key.type != BTRFS_ROOT_ITEM_KEY) {
111 : ret = 1;
112 : goto out;
113 : }
114 :
115 1915 : if (root_item)
116 1915 : btrfs_read_root_item(l, slot, root_item);
117 1915 : if (root_key)
118 1915 : memcpy(root_key, &found_key, sizeof(found_key));
119 : out:
120 2243 : btrfs_release_path(path);
121 2243 : return ret;
122 : }
123 :
124 13319 : void btrfs_set_root_node(struct btrfs_root_item *item,
125 26638 : struct extent_buffer *node)
126 : {
127 13319 : btrfs_set_root_bytenr(item, node->start);
128 : btrfs_set_root_level(item, btrfs_header_level(node));
129 : btrfs_set_root_generation(item, btrfs_header_generation(node));
130 13319 : }
131 :
132 : /*
133 : * copy the data in 'item' into the btree
134 : */
135 10015 : int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
136 : *root, struct btrfs_key *key, struct btrfs_root_item
137 : *item)
138 : {
139 : struct btrfs_path *path;
140 : struct extent_buffer *l;
141 : int ret;
142 : int slot;
143 : unsigned long ptr;
144 : int old_len;
145 :
146 10015 : path = btrfs_alloc_path();
147 10015 : if (!path)
148 : return -ENOMEM;
149 :
150 10015 : ret = btrfs_search_slot(trans, root, key, path, 0, 1);
151 10015 : if (ret < 0) {
152 0 : btrfs_abort_transaction(trans, root, ret);
153 0 : goto out;
154 : }
155 :
156 10015 : if (ret != 0) {
157 0 : btrfs_print_leaf(root, path->nodes[0]);
158 0 : btrfs_crit(root->fs_info, "unable to update root key %llu %u %llu",
159 : key->objectid, key->type, key->offset);
160 0 : BUG_ON(1);
161 : }
162 :
163 10015 : l = path->nodes[0];
164 10015 : slot = path->slots[0];
165 10015 : ptr = btrfs_item_ptr_offset(l, slot);
166 : old_len = btrfs_item_size_nr(l, slot);
167 :
168 : /*
169 : * If this is the first time we update the root item which originated
170 : * from an older kernel, we need to enlarge the item size to make room
171 : * for the added fields.
172 : */
173 10015 : if (old_len < sizeof(*item)) {
174 0 : btrfs_release_path(path);
175 0 : ret = btrfs_search_slot(trans, root, key, path,
176 : -1, 1);
177 0 : if (ret < 0) {
178 0 : btrfs_abort_transaction(trans, root, ret);
179 0 : goto out;
180 : }
181 :
182 : ret = btrfs_del_item(trans, root, path);
183 0 : if (ret < 0) {
184 0 : btrfs_abort_transaction(trans, root, ret);
185 0 : goto out;
186 : }
187 0 : btrfs_release_path(path);
188 : ret = btrfs_insert_empty_item(trans, root, path,
189 : key, sizeof(*item));
190 0 : if (ret < 0) {
191 0 : btrfs_abort_transaction(trans, root, ret);
192 0 : goto out;
193 : }
194 0 : l = path->nodes[0];
195 0 : slot = path->slots[0];
196 0 : ptr = btrfs_item_ptr_offset(l, slot);
197 : }
198 :
199 : /*
200 : * Update generation_v2 so at the next mount we know the new root
201 : * fields are valid.
202 : */
203 : btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
204 :
205 10015 : write_extent_buffer(l, item, ptr, sizeof(*item));
206 10015 : btrfs_mark_buffer_dirty(path->nodes[0]);
207 : out:
208 10015 : btrfs_free_path(path);
209 10015 : return ret;
210 : }
211 :
212 962 : int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
213 : struct btrfs_key *key, struct btrfs_root_item *item)
214 : {
215 : /*
216 : * Make sure generation v1 and v2 match. See update_root for details.
217 : */
218 : btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
219 962 : return btrfs_insert_item(trans, root, key, item, sizeof(*item));
220 : }
221 :
222 221 : int btrfs_find_orphan_roots(struct btrfs_root *tree_root)
223 : {
224 293 : struct extent_buffer *leaf;
225 : struct btrfs_path *path;
226 : struct btrfs_key key;
227 : struct btrfs_key root_key;
228 : struct btrfs_root *root;
229 : int err = 0;
230 : int ret;
231 : bool can_recover = true;
232 :
233 : if (tree_root->fs_info->sb->s_flags & MS_RDONLY)
234 : can_recover = false;
235 :
236 221 : path = btrfs_alloc_path();
237 221 : if (!path)
238 : return -ENOMEM;
239 :
240 221 : key.objectid = BTRFS_ORPHAN_OBJECTID;
241 221 : key.type = BTRFS_ORPHAN_ITEM_KEY;
242 221 : key.offset = 0;
243 :
244 221 : root_key.type = BTRFS_ROOT_ITEM_KEY;
245 221 : root_key.offset = (u64)-1;
246 :
247 : while (1) {
248 293 : ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
249 293 : if (ret < 0) {
250 : err = ret;
251 : break;
252 : }
253 :
254 293 : leaf = path->nodes[0];
255 586 : if (path->slots[0] >= btrfs_header_nritems(leaf)) {
256 221 : ret = btrfs_next_leaf(tree_root, path);
257 221 : if (ret < 0)
258 : err = ret;
259 221 : if (ret != 0)
260 : break;
261 0 : leaf = path->nodes[0];
262 : }
263 :
264 72 : btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
265 72 : btrfs_release_path(path);
266 :
267 144 : if (key.objectid != BTRFS_ORPHAN_OBJECTID ||
268 72 : key.type != BTRFS_ORPHAN_ITEM_KEY)
269 : break;
270 :
271 72 : root_key.objectid = key.offset;
272 72 : key.offset++;
273 :
274 72 : root = btrfs_read_fs_root(tree_root, &root_key);
275 : err = PTR_ERR_OR_ZERO(root);
276 72 : if (err && err != -ENOENT) {
277 : break;
278 72 : } else if (err == -ENOENT) {
279 : struct btrfs_trans_handle *trans;
280 :
281 0 : btrfs_release_path(path);
282 :
283 0 : trans = btrfs_join_transaction(tree_root);
284 0 : if (IS_ERR(trans)) {
285 0 : err = PTR_ERR(trans);
286 0 : btrfs_error(tree_root->fs_info, err,
287 : "Failed to start trans to delete "
288 : "orphan item");
289 0 : break;
290 : }
291 0 : err = btrfs_del_orphan_item(trans, tree_root,
292 : root_key.objectid);
293 0 : btrfs_end_transaction(trans, tree_root);
294 0 : if (err) {
295 0 : btrfs_error(tree_root->fs_info, err,
296 : "Failed to delete root orphan "
297 : "item");
298 0 : break;
299 : }
300 0 : continue;
301 : }
302 :
303 72 : err = btrfs_init_fs_root(root);
304 72 : if (err) {
305 0 : btrfs_free_fs_root(root);
306 0 : break;
307 : }
308 :
309 : set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state);
310 :
311 72 : err = btrfs_insert_fs_root(root->fs_info, root);
312 72 : if (err) {
313 0 : BUG_ON(err == -EEXIST);
314 0 : btrfs_free_fs_root(root);
315 0 : break;
316 : }
317 :
318 72 : if (btrfs_root_refs(&root->root_item) == 0)
319 72 : btrfs_add_dead_root(root);
320 : }
321 :
322 221 : btrfs_free_path(path);
323 221 : return err;
324 : }
325 :
326 : /* drop the root item for 'key' from 'root' */
327 450 : int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
328 : struct btrfs_key *key)
329 : {
330 : struct btrfs_path *path;
331 : int ret;
332 :
333 450 : path = btrfs_alloc_path();
334 450 : if (!path)
335 : return -ENOMEM;
336 450 : ret = btrfs_search_slot(trans, root, key, path, -1, 1);
337 450 : if (ret < 0)
338 : goto out;
339 :
340 450 : BUG_ON(ret != 0);
341 :
342 : ret = btrfs_del_item(trans, root, path);
343 : out:
344 450 : btrfs_free_path(path);
345 450 : return ret;
346 : }
347 :
348 34 : int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
349 : struct btrfs_root *tree_root,
350 : u64 root_id, u64 ref_id, u64 dirid, u64 *sequence,
351 : const char *name, int name_len)
352 :
353 : {
354 : struct btrfs_path *path;
355 : struct btrfs_root_ref *ref;
356 : struct extent_buffer *leaf;
357 : struct btrfs_key key;
358 : unsigned long ptr;
359 : int err = 0;
360 : int ret;
361 :
362 34 : path = btrfs_alloc_path();
363 34 : if (!path)
364 : return -ENOMEM;
365 :
366 34 : key.objectid = root_id;
367 34 : key.type = BTRFS_ROOT_BACKREF_KEY;
368 34 : key.offset = ref_id;
369 : again:
370 68 : ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
371 68 : BUG_ON(ret < 0);
372 68 : if (ret == 0) {
373 68 : leaf = path->nodes[0];
374 136 : ref = btrfs_item_ptr(leaf, path->slots[0],
375 : struct btrfs_root_ref);
376 :
377 68 : WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid);
378 68 : WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len);
379 68 : ptr = (unsigned long)(ref + 1);
380 68 : WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len));
381 68 : *sequence = btrfs_root_ref_sequence(leaf, ref);
382 :
383 : ret = btrfs_del_item(trans, tree_root, path);
384 68 : if (ret) {
385 : err = ret;
386 : goto out;
387 : }
388 : } else
389 : err = -ENOENT;
390 :
391 68 : if (key.type == BTRFS_ROOT_BACKREF_KEY) {
392 34 : btrfs_release_path(path);
393 34 : key.objectid = ref_id;
394 34 : key.type = BTRFS_ROOT_REF_KEY;
395 34 : key.offset = root_id;
396 34 : goto again;
397 : }
398 :
399 : out:
400 34 : btrfs_free_path(path);
401 34 : return err;
402 : }
403 :
404 : /*
405 : * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
406 : * or BTRFS_ROOT_BACKREF_KEY.
407 : *
408 : * The dirid, sequence, name and name_len refer to the directory entry
409 : * that is referencing the root.
410 : *
411 : * For a forward ref, the root_id is the id of the tree referencing
412 : * the root and ref_id is the id of the subvol or snapshot.
413 : *
414 : * For a back ref the root_id is the id of the subvol or snapshot and
415 : * ref_id is the id of the tree referencing it.
416 : *
417 : * Will return 0, -ENOMEM, or anything from the CoW path
418 : */
419 196 : int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
420 : struct btrfs_root *tree_root,
421 : u64 root_id, u64 ref_id, u64 dirid, u64 sequence,
422 : const char *name, int name_len)
423 : {
424 : struct btrfs_key key;
425 : int ret;
426 : struct btrfs_path *path;
427 : struct btrfs_root_ref *ref;
428 : struct extent_buffer *leaf;
429 : unsigned long ptr;
430 :
431 196 : path = btrfs_alloc_path();
432 196 : if (!path)
433 : return -ENOMEM;
434 :
435 196 : key.objectid = root_id;
436 196 : key.type = BTRFS_ROOT_BACKREF_KEY;
437 196 : key.offset = ref_id;
438 : again:
439 392 : ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
440 : sizeof(*ref) + name_len);
441 392 : if (ret) {
442 0 : btrfs_abort_transaction(trans, tree_root, ret);
443 0 : btrfs_free_path(path);
444 0 : return ret;
445 : }
446 :
447 392 : leaf = path->nodes[0];
448 784 : ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
449 : btrfs_set_root_ref_dirid(leaf, ref, dirid);
450 : btrfs_set_root_ref_sequence(leaf, ref, sequence);
451 392 : btrfs_set_root_ref_name_len(leaf, ref, name_len);
452 392 : ptr = (unsigned long)(ref + 1);
453 392 : write_extent_buffer(leaf, name, ptr, name_len);
454 392 : btrfs_mark_buffer_dirty(leaf);
455 :
456 392 : if (key.type == BTRFS_ROOT_BACKREF_KEY) {
457 196 : btrfs_release_path(path);
458 196 : key.objectid = ref_id;
459 196 : key.type = BTRFS_ROOT_REF_KEY;
460 196 : key.offset = root_id;
461 196 : goto again;
462 : }
463 :
464 196 : btrfs_free_path(path);
465 196 : return 0;
466 : }
467 :
468 : /*
469 : * Old btrfs forgets to init root_item->flags and root_item->byte_limit
470 : * for subvolumes. To work around this problem, we steal a bit from
471 : * root_item->inode_item->flags, and use it to indicate if those fields
472 : * have been properly initialized.
473 : */
474 1273 : void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item)
475 : {
476 : u64 inode_flags = btrfs_stack_inode_flags(&root_item->inode);
477 :
478 1273 : if (!(inode_flags & BTRFS_INODE_ROOT_ITEM_INIT)) {
479 291 : inode_flags |= BTRFS_INODE_ROOT_ITEM_INIT;
480 : btrfs_set_stack_inode_flags(&root_item->inode, inode_flags);
481 : btrfs_set_root_flags(root_item, 0);
482 : btrfs_set_root_limit(root_item, 0);
483 : }
484 1273 : }
485 :
486 170671 : void btrfs_update_root_times(struct btrfs_trans_handle *trans,
487 : struct btrfs_root *root)
488 : {
489 : struct btrfs_root_item *item = &root->root_item;
490 170671 : struct timespec ct = CURRENT_TIME;
491 :
492 : spin_lock(&root->root_item_lock);
493 170676 : btrfs_set_root_ctransid(item, trans->transid);
494 170676 : btrfs_set_stack_timespec_sec(&item->ctime, ct.tv_sec);
495 170676 : btrfs_set_stack_timespec_nsec(&item->ctime, ct.tv_nsec);
496 : spin_unlock(&root->root_item_lock);
497 170675 : }
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