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authorMark Fasheh <mark.fasheh@oracle.com>2007-12-20 19:49:04 -0500
committerMark Fasheh <mark.fasheh@oracle.com>2008-01-25 18:05:43 -0500
commit53fc622b9e829c8e632e45ef8c14f054388759c1 (patch)
tree6b8585ab00312dd798d8087c452393bf6cc0d344 /fs/ocfs2/locks.c
parentcf8e06f1a860d8680d6bb4ac8ec7d7724988e46f (diff)
[PATCH 2/2] ocfs2: cluster aware flock()
Hook up ocfs2_flock(), using the new flock lock type in dlmglue.c. A new mount option, "localflocks" is added so that users can revert to old functionality as need be. Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Diffstat (limited to 'fs/ocfs2/locks.c')
-rw-r--r--fs/ocfs2/locks.c125
1 files changed, 125 insertions, 0 deletions
diff --git a/fs/ocfs2/locks.c b/fs/ocfs2/locks.c
new file mode 100644
index 000000000000..203f87143877
--- /dev/null
+++ b/fs/ocfs2/locks.c
@@ -0,0 +1,125 @@
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
28#define MLOG_MASK_PREFIX ML_INODE
29#include <cluster/masklog.h>
30
31#include "ocfs2.h"
32
33#include "dlmglue.h"
34#include "file.h"
35#include "locks.h"
36
37static int ocfs2_do_flock(struct file *file, struct inode *inode,
38 int cmd, struct file_lock *fl)
39{
40 int ret = 0, level = 0, trylock = 0;
41 struct ocfs2_file_private *fp = file->private_data;
42 struct ocfs2_lock_res *lockres = &fp->fp_flock;
43
44 if (fl->fl_type == F_WRLCK)
45 level = 1;
46 if (!IS_SETLKW(cmd))
47 trylock = 1;
48
49 mutex_lock(&fp->fp_mutex);
50
51 if (lockres->l_flags & OCFS2_LOCK_ATTACHED &&
52 lockres->l_level > LKM_NLMODE) {
53 int old_level = 0;
54
55 if (lockres->l_level == LKM_EXMODE)
56 old_level = 1;
57
58 if (level == old_level)
59 goto out;
60
61 /*
62 * Converting an existing lock is not guaranteed to be
63 * atomic, so we can get away with simply unlocking
64 * here and allowing the lock code to try at the new
65 * level.
66 */
67
68 flock_lock_file_wait(file,
69 &(struct file_lock){.fl_type = F_UNLCK});
70
71 ocfs2_file_unlock(file);
72 }
73
74 ret = ocfs2_file_lock(file, level, trylock);
75 if (ret) {
76 if (ret == -EAGAIN && trylock)
77 ret = -EWOULDBLOCK;
78 else
79 mlog_errno(ret);
80 goto out;
81 }
82
83 ret = flock_lock_file_wait(file, fl);
84
85out:
86 mutex_unlock(&fp->fp_mutex);
87
88 return ret;
89}
90
91static int ocfs2_do_funlock(struct file *file, int cmd, struct file_lock *fl)
92{
93 int ret;
94 struct ocfs2_file_private *fp = file->private_data;
95
96 mutex_lock(&fp->fp_mutex);
97 ocfs2_file_unlock(file);
98 ret = flock_lock_file_wait(file, fl);
99 mutex_unlock(&fp->fp_mutex);
100
101 return ret;
102}
103
104/*
105 * Overall flow of ocfs2_flock() was influenced by gfs2_flock().
106 */
107int ocfs2_flock(struct file *file, int cmd, struct file_lock *fl)
108{
109 struct inode *inode = file->f_mapping->host;
110 struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
111
112 if (!(fl->fl_flags & FL_FLOCK))
113 return -ENOLCK;
114 if (__mandatory_lock(inode))
115 return -ENOLCK;
116
117 if ((osb->s_mount_opt & OCFS2_MOUNT_LOCALFLOCKS) ||
118 ocfs2_mount_local(osb))
119 return flock_lock_file_wait(file, fl);
120
121 if (fl->fl_type == F_UNLCK)
122 return ocfs2_do_funlock(file, cmd, fl);
123 else
124 return ocfs2_do_flock(file, inode, cmd, fl);
125}