Root/fs/btrfs/inode-map.c

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

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