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,
50 "generation and generation_v2 "
51 "found in root item. This root "
52 "was probably mounted with an "
53 "older kernel. Resetting all "
59 memset(&item->generation_v2, 0,
60 sizeof(*item) - offsetof(struct btrfs_root_item,
64 memcpy(item->uuid, uuid.b, BTRFS_UUID_SIZE);
69 * btrfs_find_root - lookup the root by the key.
70 * root: the root of the root tree
71 * search_key: the key to search
72 * path: the path we search
73 * root_item: the root item of the tree we look for
74 * root_key: the root key of the tree we look for
76 * If ->offset of 'search_key' is -1ULL, it means we are not sure the offset
77 * of the search key, just lookup the root with the highest offset for a
80 * If we find something return 0, otherwise > 0, < 0 on error.
82 int btrfs_find_root(struct btrfs_root *root, struct btrfs_key *search_key,
83 struct btrfs_path *path, struct btrfs_root_item *root_item,
84 struct btrfs_key *root_key)
86 struct btrfs_key found_key;
87 struct extent_buffer *l;
91 ret = btrfs_search_slot(NULL, root, search_key, path, 0, 0);
95 if (search_key->offset != -1ULL) { /* the search key is exact */
99 BUG_ON(ret == 0); /* Logical error */
100 if (path->slots[0] == 0)
107 slot = path->slots[0];
109 btrfs_item_key_to_cpu(l, &found_key, slot);
110 if (found_key.objectid != search_key->objectid ||
111 found_key.type != BTRFS_ROOT_ITEM_KEY) {
117 btrfs_read_root_item(l, slot, root_item);
119 memcpy(root_key, &found_key, sizeof(found_key));
121 btrfs_release_path(path);
125 void btrfs_set_root_node(struct btrfs_root_item *item,
126 struct extent_buffer *node)
128 btrfs_set_root_bytenr(item, node->start);
129 btrfs_set_root_level(item, btrfs_header_level(node));
130 btrfs_set_root_generation(item, btrfs_header_generation(node));
134 * copy the data in 'item' into the btree
136 int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
137 *root, struct btrfs_key *key, struct btrfs_root_item
140 struct btrfs_path *path;
141 struct extent_buffer *l;
147 path = btrfs_alloc_path();
151 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
153 btrfs_abort_transaction(trans, root, ret);
158 btrfs_print_leaf(root, path->nodes[0]);
159 btrfs_crit(root->fs_info, "unable to update root key %llu %u %llu",
160 key->objectid, key->type, key->offset);
165 slot = path->slots[0];
166 ptr = btrfs_item_ptr_offset(l, slot);
167 old_len = btrfs_item_size_nr(l, slot);
170 * If this is the first time we update the root item which originated
171 * from an older kernel, we need to enlarge the item size to make room
172 * for the added fields.
174 if (old_len < sizeof(*item)) {
175 btrfs_release_path(path);
176 ret = btrfs_search_slot(trans, root, key, path,
179 btrfs_abort_transaction(trans, root, ret);
183 ret = btrfs_del_item(trans, root, path);
185 btrfs_abort_transaction(trans, root, ret);
188 btrfs_release_path(path);
189 ret = btrfs_insert_empty_item(trans, root, path,
192 btrfs_abort_transaction(trans, root, ret);
196 slot = path->slots[0];
197 ptr = btrfs_item_ptr_offset(l, slot);
201 * Update generation_v2 so at the next mount we know the new root
204 btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
206 write_extent_buffer(l, item, ptr, sizeof(*item));
207 btrfs_mark_buffer_dirty(path->nodes[0]);
209 btrfs_free_path(path);
213 int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
214 struct btrfs_key *key, struct btrfs_root_item *item)
217 * Make sure generation v1 and v2 match. See update_root for details.
219 btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
220 return btrfs_insert_item(trans, root, key, item, sizeof(*item));
223 int btrfs_find_orphan_roots(struct btrfs_root *tree_root)
225 struct extent_buffer *leaf;
226 struct btrfs_path *path;
227 struct btrfs_key key;
228 struct btrfs_key root_key;
229 struct btrfs_root *root;
232 bool can_recover = true;
234 if (tree_root->fs_info->sb->s_flags & MS_RDONLY)
237 path = btrfs_alloc_path();
241 key.objectid = BTRFS_ORPHAN_OBJECTID;
242 key.type = BTRFS_ORPHAN_ITEM_KEY;
245 root_key.type = BTRFS_ROOT_ITEM_KEY;
246 root_key.offset = (u64)-1;
249 ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
255 leaf = path->nodes[0];
256 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
257 ret = btrfs_next_leaf(tree_root, path);
262 leaf = path->nodes[0];
265 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
266 btrfs_release_path(path);
268 if (key.objectid != BTRFS_ORPHAN_OBJECTID ||
269 key.type != BTRFS_ORPHAN_ITEM_KEY)
272 root_key.objectid = key.offset;
275 root = btrfs_read_fs_root(tree_root, &root_key);
276 err = PTR_ERR_OR_ZERO(root);
277 if (err && err != -ENOENT) {
279 } else if (err == -ENOENT) {
280 struct btrfs_trans_handle *trans;
282 btrfs_release_path(path);
284 trans = btrfs_join_transaction(tree_root);
286 err = PTR_ERR(trans);
287 btrfs_handle_fs_error(tree_root->fs_info, err,
288 "Failed to start trans to delete "
292 err = btrfs_del_orphan_item(trans, tree_root,
294 btrfs_end_transaction(trans, tree_root);
296 btrfs_handle_fs_error(tree_root->fs_info, err,
297 "Failed to delete root orphan "
304 err = btrfs_init_fs_root(root);
306 btrfs_free_fs_root(root);
310 set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state);
312 err = btrfs_insert_fs_root(root->fs_info, root);
314 * The root might have been inserted already, as before we look
315 * for orphan roots, log replay might have happened, which
316 * triggers a transaction commit and qgroup accounting, which
317 * in turn reads and inserts fs roots while doing backref
323 btrfs_free_fs_root(root);
327 if (btrfs_root_refs(&root->root_item) == 0)
328 btrfs_add_dead_root(root);
331 btrfs_free_path(path);
335 /* drop the root item for 'key' from 'root' */
336 int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
337 struct btrfs_key *key)
339 struct btrfs_path *path;
342 path = btrfs_alloc_path();
345 ret = btrfs_search_slot(trans, root, key, path, -1, 1);
351 ret = btrfs_del_item(trans, root, path);
353 btrfs_free_path(path);
357 int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
358 struct btrfs_root *tree_root,
359 u64 root_id, u64 ref_id, u64 dirid, u64 *sequence,
360 const char *name, int name_len)
363 struct btrfs_path *path;
364 struct btrfs_root_ref *ref;
365 struct extent_buffer *leaf;
366 struct btrfs_key key;
371 path = btrfs_alloc_path();
375 key.objectid = root_id;
376 key.type = BTRFS_ROOT_BACKREF_KEY;
379 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
382 leaf = path->nodes[0];
383 ref = btrfs_item_ptr(leaf, path->slots[0],
384 struct btrfs_root_ref);
386 WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid);
387 WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len);
388 ptr = (unsigned long)(ref + 1);
389 WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len));
390 *sequence = btrfs_root_ref_sequence(leaf, ref);
392 ret = btrfs_del_item(trans, tree_root, path);
400 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
401 btrfs_release_path(path);
402 key.objectid = ref_id;
403 key.type = BTRFS_ROOT_REF_KEY;
404 key.offset = root_id;
409 btrfs_free_path(path);
414 * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
415 * or BTRFS_ROOT_BACKREF_KEY.
417 * The dirid, sequence, name and name_len refer to the directory entry
418 * that is referencing the root.
420 * For a forward ref, the root_id is the id of the tree referencing
421 * the root and ref_id is the id of the subvol or snapshot.
423 * For a back ref the root_id is the id of the subvol or snapshot and
424 * ref_id is the id of the tree referencing it.
426 * Will return 0, -ENOMEM, or anything from the CoW path
428 int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
429 struct btrfs_root *tree_root,
430 u64 root_id, u64 ref_id, u64 dirid, u64 sequence,
431 const char *name, int name_len)
433 struct btrfs_key key;
435 struct btrfs_path *path;
436 struct btrfs_root_ref *ref;
437 struct extent_buffer *leaf;
440 path = btrfs_alloc_path();
444 key.objectid = root_id;
445 key.type = BTRFS_ROOT_BACKREF_KEY;
448 ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
449 sizeof(*ref) + name_len);
451 btrfs_abort_transaction(trans, tree_root, ret);
452 btrfs_free_path(path);
456 leaf = path->nodes[0];
457 ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
458 btrfs_set_root_ref_dirid(leaf, ref, dirid);
459 btrfs_set_root_ref_sequence(leaf, ref, sequence);
460 btrfs_set_root_ref_name_len(leaf, ref, name_len);
461 ptr = (unsigned long)(ref + 1);
462 write_extent_buffer(leaf, name, ptr, name_len);
463 btrfs_mark_buffer_dirty(leaf);
465 if (key.type == BTRFS_ROOT_BACKREF_KEY) {
466 btrfs_release_path(path);
467 key.objectid = ref_id;
468 key.type = BTRFS_ROOT_REF_KEY;
469 key.offset = root_id;
473 btrfs_free_path(path);
478 * Old btrfs forgets to init root_item->flags and root_item->byte_limit
479 * for subvolumes. To work around this problem, we steal a bit from
480 * root_item->inode_item->flags, and use it to indicate if those fields
481 * have been properly initialized.
483 void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item)
485 u64 inode_flags = btrfs_stack_inode_flags(&root_item->inode);
487 if (!(inode_flags & BTRFS_INODE_ROOT_ITEM_INIT)) {
488 inode_flags |= BTRFS_INODE_ROOT_ITEM_INIT;
489 btrfs_set_stack_inode_flags(&root_item->inode, inode_flags);
490 btrfs_set_root_flags(root_item, 0);
491 btrfs_set_root_limit(root_item, 0);
495 void btrfs_update_root_times(struct btrfs_trans_handle *trans,
496 struct btrfs_root *root)
498 struct btrfs_root_item *item = &root->root_item;
499 struct timespec ct = current_fs_time(root->fs_info->sb);
501 spin_lock(&root->root_item_lock);
502 btrfs_set_root_ctransid(item, trans->transid);
503 btrfs_set_stack_timespec_sec(&item->ctime, ct.tv_sec);
504 btrfs_set_stack_timespec_nsec(&item->ctime, ct.tv_nsec);
505 spin_unlock(&root->root_item_lock);