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 "ctree.h"
20 #include "disk-io.h"
21 #include "transaction.h"
22
btrfs_find_highest_inode(struct btrfs_root * root,u64 * objectid)23 int btrfs_find_highest_inode(struct btrfs_root *root, u64 *objectid)
24 {
25 struct btrfs_path *path;
26 int ret;
27 struct extent_buffer *l;
28 struct btrfs_key search_key;
29 struct btrfs_key found_key;
30 int slot;
31
32 path = btrfs_alloc_path();
33 if (!path)
34 return -ENOMEM;
35
36 search_key.objectid = BTRFS_LAST_FREE_OBJECTID;
37 search_key.type = -1;
38 search_key.offset = (u64)-1;
39 ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
40 if (ret < 0)
41 goto error;
42 BUG_ON(ret == 0);
43 if (path->slots[0] > 0) {
44 slot = path->slots[0] - 1;
45 l = path->nodes[0];
46 btrfs_item_key_to_cpu(l, &found_key, slot);
47 *objectid = max_t(u64, found_key.objectid,
48 BTRFS_FIRST_FREE_OBJECTID - 1);
49 } else {
50 *objectid = BTRFS_FIRST_FREE_OBJECTID - 1;
51 }
52 ret = 0;
53 error:
54 btrfs_free_path(path);
55 return ret;
56 }
57
btrfs_find_free_objectid(struct btrfs_trans_handle * trans,struct btrfs_root * root,u64 dirid,u64 * objectid)58 int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
59 struct btrfs_root *root,
60 u64 dirid, u64 *objectid)
61 {
62 int ret;
63 mutex_lock(&root->objectid_mutex);
64
65 if (unlikely(root->highest_objectid < BTRFS_FIRST_FREE_OBJECTID)) {
66 ret = btrfs_find_highest_inode(root, &root->highest_objectid);
67 if (ret)
68 goto out;
69 }
70
71 if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) {
72 ret = -ENOSPC;
73 goto out;
74 }
75
76 *objectid = ++root->highest_objectid;
77 ret = 0;
78 out:
79 mutex_unlock(&root->objectid_mutex);
80 return ret;
81 }
82