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1 | /* -*- mode: c; c-basic-offset: 8; -*- |
2 | * vim: noexpandtab sw=8 ts=8 sts=0: |
3 | * |
4 | * locks.c |
5 | * |
6 | * Userspace file locking support |
7 | * |
8 | * Copyright (C) 2007 Oracle. All rights reserved. |
9 | * |
10 | * This program is free software; you can redistribute it and/or |
11 | * modify it under the terms of the GNU General Public |
12 | * License as published by the Free Software Foundation; either |
13 | * version 2 of the License, or (at your option) any later version. |
14 | * |
15 | * This program is distributed in the hope that it will be useful, |
16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
18 | * General Public License for more details. |
19 | * |
20 | * You should have received a copy of the GNU General Public |
21 | * License along with this program; if not, write to the |
22 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
23 | * Boston, MA 021110-1307, USA. |
24 | */ |
25 | |
26 | #include <linux/fs.h> |
27 | #include <linux/fcntl.h> |
28 | |
29 | #include <cluster/masklog.h> |
30 | |
31 | #include "ocfs2.h" |
32 | |
33 | #include "dlmglue.h" |
34 | #include "file.h" |
35 | #include "inode.h" |
36 | #include "locks.h" |
37 | |
38 | static int ocfs2_do_flock(struct file *file, struct inode *inode, |
39 | int cmd, struct file_lock *fl) |
40 | { |
41 | int ret = 0, level = 0, trylock = 0; |
42 | struct ocfs2_file_private *fp = file->private_data; |
43 | struct ocfs2_lock_res *lockres = &fp->fp_flock; |
44 | |
45 | if (fl->fl_type == F_WRLCK) |
46 | level = 1; |
47 | if (!IS_SETLKW(cmd)) |
48 | trylock = 1; |
49 | |
50 | mutex_lock(&fp->fp_mutex); |
51 | |
52 | if (lockres->l_flags & OCFS2_LOCK_ATTACHED && |
53 | lockres->l_level > LKM_NLMODE) { |
54 | int old_level = 0; |
55 | |
56 | if (lockres->l_level == LKM_EXMODE) |
57 | old_level = 1; |
58 | |
59 | if (level == old_level) |
60 | goto out; |
61 | |
62 | /* |
63 | * Converting an existing lock is not guaranteed to be |
64 | * atomic, so we can get away with simply unlocking |
65 | * here and allowing the lock code to try at the new |
66 | * level. |
67 | */ |
68 | |
69 | flock_lock_file_wait(file, |
70 | &(struct file_lock){.fl_type = F_UNLCK}); |
71 | |
72 | ocfs2_file_unlock(file); |
73 | } |
74 | |
75 | ret = ocfs2_file_lock(file, level, trylock); |
76 | if (ret) { |
77 | if (ret == -EAGAIN && trylock) |
78 | ret = -EWOULDBLOCK; |
79 | else |
80 | mlog_errno(ret); |
81 | goto out; |
82 | } |
83 | |
84 | ret = flock_lock_file_wait(file, fl); |
85 | |
86 | out: |
87 | mutex_unlock(&fp->fp_mutex); |
88 | |
89 | return ret; |
90 | } |
91 | |
92 | static int ocfs2_do_funlock(struct file *file, int cmd, struct file_lock *fl) |
93 | { |
94 | int ret; |
95 | struct ocfs2_file_private *fp = file->private_data; |
96 | |
97 | mutex_lock(&fp->fp_mutex); |
98 | ocfs2_file_unlock(file); |
99 | ret = flock_lock_file_wait(file, fl); |
100 | mutex_unlock(&fp->fp_mutex); |
101 | |
102 | return ret; |
103 | } |
104 | |
105 | /* |
106 | * Overall flow of ocfs2_flock() was influenced by gfs2_flock(). |
107 | */ |
108 | int ocfs2_flock(struct file *file, int cmd, struct file_lock *fl) |
109 | { |
110 | struct inode *inode = file->f_mapping->host; |
111 | struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); |
112 | |
113 | if (!(fl->fl_flags & FL_FLOCK)) |
114 | return -ENOLCK; |
115 | if (__mandatory_lock(inode)) |
116 | return -ENOLCK; |
117 | |
118 | if ((osb->s_mount_opt & OCFS2_MOUNT_LOCALFLOCKS) || |
119 | ocfs2_mount_local(osb)) |
120 | return flock_lock_file_wait(file, fl); |
121 | |
122 | if (fl->fl_type == F_UNLCK) |
123 | return ocfs2_do_funlock(file, cmd, fl); |
124 | else |
125 | return ocfs2_do_flock(file, inode, cmd, fl); |
126 | } |
127 | |
128 | int ocfs2_lock(struct file *file, int cmd, struct file_lock *fl) |
129 | { |
130 | struct inode *inode = file->f_mapping->host; |
131 | struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); |
132 | |
133 | if (!(fl->fl_flags & FL_POSIX)) |
134 | return -ENOLCK; |
135 | if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK) |
136 | return -ENOLCK; |
137 | |
138 | return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl); |
139 | } |
140 |
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od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
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v3.9