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925baedd CM |
1 | /* |
2 | * Copyright (C) 2008 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 | #include <linux/sched.h> | |
19 | #include <linux/gfp.h> | |
20 | #include <linux/pagemap.h> | |
21 | #include <linux/spinlock.h> | |
22 | #include <linux/page-flags.h> | |
4881ee5a | 23 | #include <asm/bug.h> |
925baedd CM |
24 | #include "ctree.h" |
25 | #include "extent_io.h" | |
26 | #include "locking.h" | |
27 | ||
28 | int btrfs_tree_lock(struct extent_buffer *eb) | |
29 | { | |
f9efa9c7 CM |
30 | int i; |
31 | ||
a61e6f29 | 32 | if (mutex_trylock(&eb->mutex)) |
f9efa9c7 CM |
33 | return 0; |
34 | for (i = 0; i < 512; i++) { | |
35 | cpu_relax(); | |
a61e6f29 | 36 | if (mutex_trylock(&eb->mutex)) |
f9efa9c7 CM |
37 | return 0; |
38 | } | |
39 | cpu_relax(); | |
6dddcbeb | 40 | mutex_lock_nested(&eb->mutex, BTRFS_MAX_LEVEL - btrfs_header_level(eb)); |
925baedd CM |
41 | return 0; |
42 | } | |
43 | ||
44 | int btrfs_try_tree_lock(struct extent_buffer *eb) | |
45 | { | |
a61e6f29 | 46 | return mutex_trylock(&eb->mutex); |
925baedd CM |
47 | } |
48 | ||
49 | int btrfs_tree_unlock(struct extent_buffer *eb) | |
50 | { | |
a61e6f29 | 51 | mutex_unlock(&eb->mutex); |
925baedd CM |
52 | return 0; |
53 | } | |
54 | ||
55 | int btrfs_tree_locked(struct extent_buffer *eb) | |
56 | { | |
a61e6f29 | 57 | return mutex_is_locked(&eb->mutex); |
925baedd | 58 | } |
65b51a00 CM |
59 | |
60 | int btrfs_path_lock_waiting(struct btrfs_path *path, int level) | |
61 | { | |
62 | int i; | |
63 | struct extent_buffer *eb; | |
64 | for (i = level; i <= level + 1 && i < BTRFS_MAX_LEVEL; i++) { | |
65 | eb = path->nodes[i]; | |
66 | if (!eb) | |
67 | break; | |
68 | smp_mb(); | |
69 | if (!list_empty(&eb->mutex.wait_list)) | |
70 | return 1; | |
71 | } | |
72 | return 0; | |
73 | } | |
74 |