2 * Copyright (C) 2007 Oracle. All rights reserved.
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.
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.
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.
19 #include <linux/err.h>
20 #include <linux/uuid.h>
22 #include "transaction.h"
24 #include "print-tree.h"
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.
33 static void btrfs_read_root_item(struct extent_buffer *eb, int slot,
34 struct btrfs_root_item *item)
40 len = btrfs_item_size_nr(eb, slot);
41 read_extent_buffer(eb, item, btrfs_item_ptr_offset(eb, slot),
42 min_t(int, len, (int)sizeof(*item)));
43 if (len < sizeof(*item))
45 if (!need_reset && btrfs_root_generation(item)
46 != btrfs_root_generation_v2(item)) {
47 if (btrfs_root_generation_v2(item) != 0) {
48 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 "
58 memset(&item->generation_v2, 0,
59 sizeof(*item) - offsetof(struct btrfs_root_item,
63 memcpy(item->uuid, uuid.b, BTRFS_UUID_SIZE);
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
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
79 * If we find something return 0, otherwise > 0, < 0 on error.
81 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)
85 struct btrfs_key found_key;
86 struct extent_buffer *l;
90 ret = btrfs_search_slot(NULL, root, search_key, path, 0, 0);
94 if (search_key->offset != -1ULL) { /* the search key is exact */
98 BUG_ON(ret == 0); /* Logical error */
99 if (path->slots[0] == 0)
106 slot = path->slots[0];
108 btrfs_item_key_to_cpu(l, &found_key, slot);
109 if (found_key.objectid != search_key->objectid ||
110 found_key.type != BTRFS_ROOT_ITEM_KEY) {
116 btrfs_read_root_item(l, slot, root_item);
118 memcpy(root_key, &found_key, sizeof(found_key));
120 btrfs_release_path(path);
124 void btrfs_set_root_node(struct btrfs_root_item *item,
125 struct extent_buffer *node)
127 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));
133 * copy the data in 'item' into the btree
135 int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
136 *root, struct btrfs_key *key, struct btrfs_root_item
139 struct btrfs_path *path;
140 struct extent_buffer *l;
146 path = btrfs_alloc_path();
150 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
152 btrfs_abort_transaction(trans, root, ret);
157 btrfs_print_leaf(root, path->nodes[0]);
158 btrfs_crit(root->fs_info, "unable to update root key %llu %u %llu",
159 key->objectid, key->type, key->offset);
164 slot = path->slots[0];
165 ptr = btrfs_item_ptr_offset(l, slot);
166 old_len = btrfs_item_size_nr(l, slot);
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.
173 if (old_len < sizeof(*item)) {
174 btrfs_release_path(path);
175 ret = btrfs_search_slot(trans, root, key, path,
178 btrfs_abort_transaction(trans, root, ret);
182 ret = btrfs_del_item(trans, root, path);
184 btrfs_abort_transaction(trans, root, ret);
187 btrfs_release_path(path);
188 ret = btrfs_insert_empty_item(trans, root, path,
191 btrfs_abort_transaction(trans, root, ret);
195 slot = path->slots[0];
196 ptr = btrfs_item_ptr_offset(l, slot);
200 * Update generation_v2 so at the next mount we know the new root
203 btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
205 write_extent_buffer(l, item, ptr, sizeof(*item));
206 btrfs_mark_buffer_dirty(path->nodes[0]);
208 btrfs_free_path(path);
212 int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
213 struct btrfs_key *key, struct btrfs_root_item *item)
216 * Make sure generation v1 and v2 match. See update_root for details.
218 btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
219 return btrfs_insert_item(trans, root, key, item, sizeof(*item));
222 int btrfs_find_orphan_roots(struct btrfs_root *tree_root)
224 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;
231 bool can_recover = true;
233 if (tree_root->fs_info->sb->s_flags & MS_RDONLY)
236 path = btrfs_alloc_path();
240 key.objectid = BTRFS_ORPHAN_OBJECTID;
241 key.type = BTRFS_ORPHAN_ITEM_KEY;
244 root_key.type = BTRFS_ROOT_ITEM_KEY;
245 root_key.offset = (u64)-1;
248 ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
254 leaf = path->nodes[0];
255 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
256 ret = btrfs_next_leaf(tree_root, path);
261 leaf = path->nodes[0];
264 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
265 btrfs_release_path(path);
267 if (key.objectid != BTRFS_ORPHAN_OBJECTID ||
268 key.type != BTRFS_ORPHAN_ITEM_KEY)
271 root_key.objectid = key.offset;
274 root = btrfs_read_fs_root(tree_root, &root_key);
275 err = PTR_ERR_OR_ZERO(root);
276 if (err && err != -ENOENT) {
278 } else if (err == -ENOENT) {
279 struct btrfs_trans_handle *trans;
281 btrfs_release_path(path);
283 trans = btrfs_join_transaction(tree_root);
285 err = PTR_ERR(trans);
286 btrfs_error(tree_root->fs_info, err,
287 "Failed to start trans to delete "
291 err = btrfs_del_orphan_item(trans, tree_root,
293 btrfs_end_transaction(trans, tree_root);
295 btrfs_error(tree_root->fs_info, err,
296 "Failed to delete root orphan "
303 err = btrfs_init_fs_root(root);
305 btrfs_free_fs_root(root);
309 set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state);
311 err = btrfs_insert_fs_root(root->fs_info, root);
313 BUG_ON(err == -EEXIST);
314 btrfs_free_fs_root(root);
318 if (btrfs_root_refs(&root->root_item) == 0)
319 btrfs_add_dead_root(root);
322 btrfs_free_path(path);
326 /* drop the root item for 'key' from 'root' */
327 int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
328 struct btrfs_key *key)
330 struct btrfs_path *path;
333 path = btrfs_alloc_path();
336 ret = btrfs_search_slot(trans, root, key, path, -1, 1);
342 ret = btrfs_del_item(trans, root, path);
344 btrfs_free_path(path);
348 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)
354 struct btrfs_path *path;
355 struct btrfs_root_ref *ref;
356 struct extent_buffer *leaf;
357 struct btrfs_key key;
362 path = btrfs_alloc_path();
366 key.objectid = root_id;
367 key.type = BTRFS_ROOT_BACKREF_KEY;
370 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
373 leaf = path->nodes[0];
374 ref = btrfs_item_ptr(leaf, path->slots[0],
375 struct btrfs_root_ref);
377 WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid);
378 WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len);
379 ptr = (unsigned long)(ref + 1);
380 WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len));
381 *sequence = btrfs_root_ref_sequence(leaf, ref);
383 ret = btrfs_del_item(trans, tree_root, path);
391 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
392 btrfs_release_path(path);
393 key.objectid = ref_id;
394 key.type = BTRFS_ROOT_REF_KEY;
395 key.offset = root_id;
400 btrfs_free_path(path);
405 * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
406 * or BTRFS_ROOT_BACKREF_KEY.
408 * The dirid, sequence, name and name_len refer to the directory entry
409 * that is referencing the root.
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.
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.
417 * Will return 0, -ENOMEM, or anything from the CoW path
419 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)
424 struct btrfs_key key;
426 struct btrfs_path *path;
427 struct btrfs_root_ref *ref;
428 struct extent_buffer *leaf;
431 path = btrfs_alloc_path();
435 key.objectid = root_id;
436 key.type = BTRFS_ROOT_BACKREF_KEY;
439 ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
440 sizeof(*ref) + name_len);
442 btrfs_abort_transaction(trans, tree_root, ret);
443 btrfs_free_path(path);
447 leaf = path->nodes[0];
448 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 btrfs_set_root_ref_name_len(leaf, ref, name_len);
452 ptr = (unsigned long)(ref + 1);
453 write_extent_buffer(leaf, name, ptr, name_len);
454 btrfs_mark_buffer_dirty(leaf);
456 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
457 btrfs_release_path(path);
458 key.objectid = ref_id;
459 key.type = BTRFS_ROOT_REF_KEY;
460 key.offset = root_id;
464 btrfs_free_path(path);
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.
474 void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item)
476 u64 inode_flags = btrfs_stack_inode_flags(&root_item->inode);
478 if (!(inode_flags & BTRFS_INODE_ROOT_ITEM_INIT)) {
479 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);
486 void btrfs_update_root_times(struct btrfs_trans_handle *trans,
487 struct btrfs_root *root)
489 struct btrfs_root_item *item = &root->root_item;
490 struct timespec ct = CURRENT_TIME;
492 spin_lock(&root->root_item_lock);
493 btrfs_set_root_ctransid(item, trans->transid);
494 btrfs_set_stack_timespec_sec(&item->ctime, ct.tv_sec);
495 btrfs_set_stack_timespec_nsec(&item->ctime, ct.tv_nsec);
496 spin_unlock(&root->root_item_lock);