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 btrfs_warn(eb->fs_info,
49 "mismatching generation and generation_v2 found in root item. This root was probably mounted with an older kernel. Resetting all new fields.");
54 memset(&item->generation_v2, 0,
55 sizeof(*item) - offsetof(struct btrfs_root_item,
59 memcpy(item->uuid, uuid.b, BTRFS_UUID_SIZE);
64 * btrfs_find_root - lookup the root by the key.
65 * root: the root of the root tree
66 * search_key: the key to search
67 * path: the path we search
68 * root_item: the root item of the tree we look for
69 * root_key: the root key of the tree we look for
71 * If ->offset of 'search_key' is -1ULL, it means we are not sure the offset
72 * of the search key, just lookup the root with the highest offset for a
75 * If we find something return 0, otherwise > 0, < 0 on error.
77 int btrfs_find_root(struct btrfs_root *root, struct btrfs_key *search_key,
78 struct btrfs_path *path, struct btrfs_root_item *root_item,
79 struct btrfs_key *root_key)
81 struct btrfs_key found_key;
82 struct extent_buffer *l;
86 ret = btrfs_search_slot(NULL, root, search_key, path, 0, 0);
90 if (search_key->offset != -1ULL) { /* the search key is exact */
94 BUG_ON(ret == 0); /* Logical error */
95 if (path->slots[0] == 0)
102 slot = path->slots[0];
104 btrfs_item_key_to_cpu(l, &found_key, slot);
105 if (found_key.objectid != search_key->objectid ||
106 found_key.type != BTRFS_ROOT_ITEM_KEY) {
112 btrfs_read_root_item(l, slot, root_item);
114 memcpy(root_key, &found_key, sizeof(found_key));
116 btrfs_release_path(path);
120 void btrfs_set_root_node(struct btrfs_root_item *item,
121 struct extent_buffer *node)
123 btrfs_set_root_bytenr(item, node->start);
124 btrfs_set_root_level(item, btrfs_header_level(node));
125 btrfs_set_root_generation(item, btrfs_header_generation(node));
129 * copy the data in 'item' into the btree
131 int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
132 *root, struct btrfs_key *key, struct btrfs_root_item
135 struct btrfs_path *path;
136 struct extent_buffer *l;
142 path = btrfs_alloc_path();
146 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
151 btrfs_print_leaf(root, path->nodes[0]);
152 btrfs_crit(root->fs_info,
153 "unable to update root key %llu %u %llu",
154 key->objectid, key->type, key->offset);
159 slot = path->slots[0];
160 ptr = btrfs_item_ptr_offset(l, slot);
161 old_len = btrfs_item_size_nr(l, slot);
164 * If this is the first time we update the root item which originated
165 * from an older kernel, we need to enlarge the item size to make room
166 * for the added fields.
168 if (old_len < sizeof(*item)) {
169 btrfs_release_path(path);
170 ret = btrfs_search_slot(trans, root, key, path,
173 btrfs_abort_transaction(trans, ret);
177 ret = btrfs_del_item(trans, root, path);
179 btrfs_abort_transaction(trans, ret);
182 btrfs_release_path(path);
183 ret = btrfs_insert_empty_item(trans, root, path,
186 btrfs_abort_transaction(trans, ret);
190 slot = path->slots[0];
191 ptr = btrfs_item_ptr_offset(l, slot);
195 * Update generation_v2 so at the next mount we know the new root
198 btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
200 write_extent_buffer(l, item, ptr, sizeof(*item));
201 btrfs_mark_buffer_dirty(path->nodes[0]);
203 btrfs_free_path(path);
207 int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
208 struct btrfs_key *key, struct btrfs_root_item *item)
211 * Make sure generation v1 and v2 match. See update_root for details.
213 btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
214 return btrfs_insert_item(trans, root, key, item, sizeof(*item));
217 int btrfs_find_orphan_roots(struct btrfs_root *tree_root)
219 struct extent_buffer *leaf;
220 struct btrfs_path *path;
221 struct btrfs_key key;
222 struct btrfs_key root_key;
223 struct btrfs_root *root;
226 bool can_recover = true;
228 if (tree_root->fs_info->sb->s_flags & MS_RDONLY)
231 path = btrfs_alloc_path();
235 key.objectid = BTRFS_ORPHAN_OBJECTID;
236 key.type = BTRFS_ORPHAN_ITEM_KEY;
239 root_key.type = BTRFS_ROOT_ITEM_KEY;
240 root_key.offset = (u64)-1;
243 ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
249 leaf = path->nodes[0];
250 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
251 ret = btrfs_next_leaf(tree_root, path);
256 leaf = path->nodes[0];
259 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
260 btrfs_release_path(path);
262 if (key.objectid != BTRFS_ORPHAN_OBJECTID ||
263 key.type != BTRFS_ORPHAN_ITEM_KEY)
266 root_key.objectid = key.offset;
270 * The root might have been inserted already, as before we look
271 * for orphan roots, log replay might have happened, which
272 * triggers a transaction commit and qgroup accounting, which
273 * in turn reads and inserts fs roots while doing backref
276 root = btrfs_lookup_fs_root(tree_root->fs_info,
279 WARN_ON(!test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
281 if (btrfs_root_refs(&root->root_item) == 0)
282 btrfs_add_dead_root(root);
286 root = btrfs_read_fs_root(tree_root, &root_key);
287 err = PTR_ERR_OR_ZERO(root);
288 if (err && err != -ENOENT) {
290 } else if (err == -ENOENT) {
291 struct btrfs_trans_handle *trans;
293 btrfs_release_path(path);
295 trans = btrfs_join_transaction(tree_root);
297 err = PTR_ERR(trans);
298 btrfs_handle_fs_error(tree_root->fs_info, err,
299 "Failed to start trans to delete orphan item");
302 err = btrfs_del_orphan_item(trans, tree_root,
304 btrfs_end_transaction(trans, tree_root);
306 btrfs_handle_fs_error(tree_root->fs_info, err,
307 "Failed to delete root orphan item");
313 err = btrfs_init_fs_root(root);
315 btrfs_free_fs_root(root);
319 set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state);
321 err = btrfs_insert_fs_root(root->fs_info, root);
323 BUG_ON(err == -EEXIST);
324 btrfs_free_fs_root(root);
328 if (btrfs_root_refs(&root->root_item) == 0)
329 btrfs_add_dead_root(root);
332 btrfs_free_path(path);
336 /* drop the root item for 'key' from 'root' */
337 int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
338 struct btrfs_key *key)
340 struct btrfs_path *path;
343 path = btrfs_alloc_path();
346 ret = btrfs_search_slot(trans, root, key, path, -1, 1);
352 ret = btrfs_del_item(trans, root, path);
354 btrfs_free_path(path);
358 int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
359 struct btrfs_root *tree_root,
360 u64 root_id, u64 ref_id, u64 dirid, u64 *sequence,
361 const char *name, int name_len)
364 struct btrfs_path *path;
365 struct btrfs_root_ref *ref;
366 struct extent_buffer *leaf;
367 struct btrfs_key key;
372 path = btrfs_alloc_path();
376 key.objectid = root_id;
377 key.type = BTRFS_ROOT_BACKREF_KEY;
380 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
383 leaf = path->nodes[0];
384 ref = btrfs_item_ptr(leaf, path->slots[0],
385 struct btrfs_root_ref);
387 WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid);
388 WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len);
389 ptr = (unsigned long)(ref + 1);
390 WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len));
391 *sequence = btrfs_root_ref_sequence(leaf, ref);
393 ret = btrfs_del_item(trans, tree_root, path);
401 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
402 btrfs_release_path(path);
403 key.objectid = ref_id;
404 key.type = BTRFS_ROOT_REF_KEY;
405 key.offset = root_id;
410 btrfs_free_path(path);
415 * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
416 * or BTRFS_ROOT_BACKREF_KEY.
418 * The dirid, sequence, name and name_len refer to the directory entry
419 * that is referencing the root.
421 * For a forward ref, the root_id is the id of the tree referencing
422 * the root and ref_id is the id of the subvol or snapshot.
424 * For a back ref the root_id is the id of the subvol or snapshot and
425 * ref_id is the id of the tree referencing it.
427 * Will return 0, -ENOMEM, or anything from the CoW path
429 int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
430 struct btrfs_root *tree_root,
431 u64 root_id, u64 ref_id, u64 dirid, u64 sequence,
432 const char *name, int name_len)
434 struct btrfs_key key;
436 struct btrfs_path *path;
437 struct btrfs_root_ref *ref;
438 struct extent_buffer *leaf;
441 path = btrfs_alloc_path();
445 key.objectid = root_id;
446 key.type = BTRFS_ROOT_BACKREF_KEY;
449 ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
450 sizeof(*ref) + name_len);
452 btrfs_abort_transaction(trans, ret);
453 btrfs_free_path(path);
457 leaf = path->nodes[0];
458 ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
459 btrfs_set_root_ref_dirid(leaf, ref, dirid);
460 btrfs_set_root_ref_sequence(leaf, ref, sequence);
461 btrfs_set_root_ref_name_len(leaf, ref, name_len);
462 ptr = (unsigned long)(ref + 1);
463 write_extent_buffer(leaf, name, ptr, name_len);
464 btrfs_mark_buffer_dirty(leaf);
466 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
467 btrfs_release_path(path);
468 key.objectid = ref_id;
469 key.type = BTRFS_ROOT_REF_KEY;
470 key.offset = root_id;
474 btrfs_free_path(path);
479 * Old btrfs forgets to init root_item->flags and root_item->byte_limit
480 * for subvolumes. To work around this problem, we steal a bit from
481 * root_item->inode_item->flags, and use it to indicate if those fields
482 * have been properly initialized.
484 void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item)
486 u64 inode_flags = btrfs_stack_inode_flags(&root_item->inode);
488 if (!(inode_flags & BTRFS_INODE_ROOT_ITEM_INIT)) {
489 inode_flags |= BTRFS_INODE_ROOT_ITEM_INIT;
490 btrfs_set_stack_inode_flags(&root_item->inode, inode_flags);
491 btrfs_set_root_flags(root_item, 0);
492 btrfs_set_root_limit(root_item, 0);
496 void btrfs_update_root_times(struct btrfs_trans_handle *trans,
497 struct btrfs_root *root)
499 struct btrfs_root_item *item = &root->root_item;
500 struct timespec ct = current_fs_time(root->fs_info->sb);
502 spin_lock(&root->root_item_lock);
503 btrfs_set_root_ctransid(item, trans->transid);
504 btrfs_set_stack_timespec_sec(&item->ctime, ct.tv_sec);
505 btrfs_set_stack_timespec_nsec(&item->ctime, ct.tv_nsec);
506 spin_unlock(&root->root_item_lock);