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/uuid.h>
21 #include "transaction.h"
23 #include "print-tree.h"
26 * Read a root item from the tree. In case we detect a root item smaller then
27 * sizeof(root_item), we know it's an old version of the root structure and
28 * initialize all new fields to zero. The same happens if we detect mismatching
29 * generation numbers as then we know the root was once mounted with an older
30 * kernel that was not aware of the root item structure change.
32 void btrfs_read_root_item(struct extent_buffer *eb, int slot,
33 struct btrfs_root_item *item)
39 len = btrfs_item_size_nr(eb, slot);
40 read_extent_buffer(eb, item, btrfs_item_ptr_offset(eb, slot),
41 min_t(int, len, (int)sizeof(*item)));
42 if (len < sizeof(*item))
44 if (!need_reset && btrfs_root_generation(item)
45 != btrfs_root_generation_v2(item)) {
46 if (btrfs_root_generation_v2(item) != 0) {
47 printk(KERN_WARNING "btrfs: mismatching "
48 "generation and generation_v2 "
49 "found in root item. This root "
50 "was probably mounted with an "
51 "older kernel. Resetting all "
57 memset(&item->generation_v2, 0,
58 sizeof(*item) - offsetof(struct btrfs_root_item,
62 memcpy(item->uuid, uuid.b, BTRFS_UUID_SIZE);
67 * btrfs_find_root - lookup the root by the key.
68 * root: the root of the root tree
69 * search_key: the key to search
70 * path: the path we search
71 * root_item: the root item of the tree we look for
72 * root_key: the reak key of the tree we look for
74 * If ->offset of 'seach_key' is -1ULL, it means we are not sure the offset
75 * of the search key, just lookup the root with the highest offset for a
78 * If we find something return 0, otherwise > 0, < 0 on error.
80 int btrfs_find_root(struct btrfs_root *root, struct btrfs_key *search_key,
81 struct btrfs_path *path, struct btrfs_root_item *root_item,
82 struct btrfs_key *root_key)
84 struct btrfs_key found_key;
85 struct extent_buffer *l;
89 ret = btrfs_search_slot(NULL, root, search_key, path, 0, 0);
93 if (search_key->offset != -1ULL) { /* the search key is exact */
97 BUG_ON(ret == 0); /* Logical error */
98 if (path->slots[0] == 0)
105 slot = path->slots[0];
107 btrfs_item_key_to_cpu(l, &found_key, slot);
108 if (found_key.objectid != search_key->objectid ||
109 found_key.type != BTRFS_ROOT_ITEM_KEY) {
115 btrfs_read_root_item(l, slot, root_item);
117 memcpy(root_key, &found_key, sizeof(found_key));
119 btrfs_release_path(path);
123 void btrfs_set_root_node(struct btrfs_root_item *item,
124 struct extent_buffer *node)
126 btrfs_set_root_bytenr(item, node->start);
127 btrfs_set_root_level(item, btrfs_header_level(node));
128 btrfs_set_root_generation(item, btrfs_header_generation(node));
132 * copy the data in 'item' into the btree
134 int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
135 *root, struct btrfs_key *key, struct btrfs_root_item
138 struct btrfs_path *path;
139 struct extent_buffer *l;
145 path = btrfs_alloc_path();
149 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
151 btrfs_abort_transaction(trans, root, ret);
156 btrfs_print_leaf(root, path->nodes[0]);
157 printk(KERN_CRIT "unable to update root key %llu %u %llu\n",
158 (unsigned long long)key->objectid, key->type,
159 (unsigned long long)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);
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 if (btrfs_root_refs(&root->root_item) == 0) {
304 btrfs_add_dead_root(root);
308 err = btrfs_init_fs_root(root);
310 btrfs_free_fs_root(root);
314 root->orphan_item_inserted = 1;
316 err = btrfs_insert_fs_root(root->fs_info, root);
318 BUG_ON(err == -EEXIST);
319 btrfs_free_fs_root(root);
324 btrfs_free_path(path);
328 /* drop the root item for 'key' from 'root' */
329 int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
330 struct btrfs_key *key)
332 struct btrfs_path *path;
335 path = btrfs_alloc_path();
338 ret = btrfs_search_slot(trans, root, key, path, -1, 1);
344 ret = btrfs_del_item(trans, root, path);
346 btrfs_free_path(path);
350 int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
351 struct btrfs_root *tree_root,
352 u64 root_id, u64 ref_id, u64 dirid, u64 *sequence,
353 const char *name, int name_len)
356 struct btrfs_path *path;
357 struct btrfs_root_ref *ref;
358 struct extent_buffer *leaf;
359 struct btrfs_key key;
364 path = btrfs_alloc_path();
368 key.objectid = root_id;
369 key.type = BTRFS_ROOT_BACKREF_KEY;
372 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
375 leaf = path->nodes[0];
376 ref = btrfs_item_ptr(leaf, path->slots[0],
377 struct btrfs_root_ref);
379 WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid);
380 WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len);
381 ptr = (unsigned long)(ref + 1);
382 WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len));
383 *sequence = btrfs_root_ref_sequence(leaf, ref);
385 ret = btrfs_del_item(trans, tree_root, path);
393 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
394 btrfs_release_path(path);
395 key.objectid = ref_id;
396 key.type = BTRFS_ROOT_REF_KEY;
397 key.offset = root_id;
402 btrfs_free_path(path);
406 int btrfs_find_root_ref(struct btrfs_root *tree_root,
407 struct btrfs_path *path,
408 u64 root_id, u64 ref_id)
410 struct btrfs_key key;
413 key.objectid = root_id;
414 key.type = BTRFS_ROOT_REF_KEY;
417 ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
422 * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
423 * or BTRFS_ROOT_BACKREF_KEY.
425 * The dirid, sequence, name and name_len refer to the directory entry
426 * that is referencing the root.
428 * For a forward ref, the root_id is the id of the tree referencing
429 * the root and ref_id is the id of the subvol or snapshot.
431 * For a back ref the root_id is the id of the subvol or snapshot and
432 * ref_id is the id of the tree referencing it.
434 * Will return 0, -ENOMEM, or anything from the CoW path
436 int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
437 struct btrfs_root *tree_root,
438 u64 root_id, u64 ref_id, u64 dirid, u64 sequence,
439 const char *name, int name_len)
441 struct btrfs_key key;
443 struct btrfs_path *path;
444 struct btrfs_root_ref *ref;
445 struct extent_buffer *leaf;
448 path = btrfs_alloc_path();
452 key.objectid = root_id;
453 key.type = BTRFS_ROOT_BACKREF_KEY;
456 ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
457 sizeof(*ref) + name_len);
459 btrfs_abort_transaction(trans, tree_root, ret);
460 btrfs_free_path(path);
464 leaf = path->nodes[0];
465 ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
466 btrfs_set_root_ref_dirid(leaf, ref, dirid);
467 btrfs_set_root_ref_sequence(leaf, ref, sequence);
468 btrfs_set_root_ref_name_len(leaf, ref, name_len);
469 ptr = (unsigned long)(ref + 1);
470 write_extent_buffer(leaf, name, ptr, name_len);
471 btrfs_mark_buffer_dirty(leaf);
473 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
474 btrfs_release_path(path);
475 key.objectid = ref_id;
476 key.type = BTRFS_ROOT_REF_KEY;
477 key.offset = root_id;
481 btrfs_free_path(path);
486 * Old btrfs forgets to init root_item->flags and root_item->byte_limit
487 * for subvolumes. To work around this problem, we steal a bit from
488 * root_item->inode_item->flags, and use it to indicate if those fields
489 * have been properly initialized.
491 void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item)
493 u64 inode_flags = le64_to_cpu(root_item->inode.flags);
495 if (!(inode_flags & BTRFS_INODE_ROOT_ITEM_INIT)) {
496 inode_flags |= BTRFS_INODE_ROOT_ITEM_INIT;
497 root_item->inode.flags = cpu_to_le64(inode_flags);
498 root_item->flags = 0;
499 root_item->byte_limit = 0;
503 void btrfs_update_root_times(struct btrfs_trans_handle *trans,
504 struct btrfs_root *root)
506 struct btrfs_root_item *item = &root->root_item;
507 struct timespec ct = CURRENT_TIME;
509 spin_lock(&root->root_item_lock);
510 item->ctransid = cpu_to_le64(trans->transid);
511 item->ctime.sec = cpu_to_le64(ct.tv_sec);
512 item->ctime.nsec = cpu_to_le32(ct.tv_nsec);
513 spin_unlock(&root->root_item_lock);