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53fc622b MF |
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> | |
53da4939 | 27 | #include <linux/fcntl.h> |
53fc622b | 28 | |
53fc622b MF |
29 | #include <cluster/masklog.h> |
30 | ||
31 | #include "ocfs2.h" | |
32 | ||
33 | #include "dlmglue.h" | |
34 | #include "file.h" | |
53da4939 | 35 | #include "inode.h" |
53fc622b MF |
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; | |
4316c3c6 | 55 | struct file_lock request; |
53fc622b MF |
56 | |
57 | if (lockres->l_level == LKM_EXMODE) | |
58 | old_level = 1; | |
59 | ||
60 | if (level == old_level) | |
61 | goto out; | |
62 | ||
63 | /* | |
64 | * Converting an existing lock is not guaranteed to be | |
65 | * atomic, so we can get away with simply unlocking | |
66 | * here and allowing the lock code to try at the new | |
67 | * level. | |
68 | */ | |
69 | ||
4316c3c6 N |
70 | locks_init_lock(&request); |
71 | request.fl_type = F_UNLCK; | |
72 | request.fl_flags = FL_FLOCK; | |
73 | locks_lock_file_wait(file, &request); | |
53fc622b MF |
74 | |
75 | ocfs2_file_unlock(file); | |
76 | } | |
77 | ||
78 | ret = ocfs2_file_lock(file, level, trylock); | |
79 | if (ret) { | |
80 | if (ret == -EAGAIN && trylock) | |
81 | ret = -EWOULDBLOCK; | |
82 | else | |
83 | mlog_errno(ret); | |
84 | goto out; | |
85 | } | |
86 | ||
4f656367 | 87 | ret = locks_lock_file_wait(file, fl); |
e228f643 WW |
88 | if (ret) |
89 | ocfs2_file_unlock(file); | |
53fc622b MF |
90 | |
91 | out: | |
92 | mutex_unlock(&fp->fp_mutex); | |
93 | ||
94 | return ret; | |
95 | } | |
96 | ||
97 | static int ocfs2_do_funlock(struct file *file, int cmd, struct file_lock *fl) | |
98 | { | |
99 | int ret; | |
100 | struct ocfs2_file_private *fp = file->private_data; | |
101 | ||
102 | mutex_lock(&fp->fp_mutex); | |
103 | ocfs2_file_unlock(file); | |
4f656367 | 104 | ret = locks_lock_file_wait(file, fl); |
53fc622b MF |
105 | mutex_unlock(&fp->fp_mutex); |
106 | ||
107 | return ret; | |
108 | } | |
109 | ||
110 | /* | |
111 | * Overall flow of ocfs2_flock() was influenced by gfs2_flock(). | |
112 | */ | |
113 | int ocfs2_flock(struct file *file, int cmd, struct file_lock *fl) | |
114 | { | |
115 | struct inode *inode = file->f_mapping->host; | |
116 | struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); | |
117 | ||
118 | if (!(fl->fl_flags & FL_FLOCK)) | |
119 | return -ENOLCK; | |
120 | if (__mandatory_lock(inode)) | |
121 | return -ENOLCK; | |
122 | ||
123 | if ((osb->s_mount_opt & OCFS2_MOUNT_LOCALFLOCKS) || | |
124 | ocfs2_mount_local(osb)) | |
4f656367 | 125 | return locks_lock_file_wait(file, fl); |
53fc622b MF |
126 | |
127 | if (fl->fl_type == F_UNLCK) | |
128 | return ocfs2_do_funlock(file, cmd, fl); | |
129 | else | |
130 | return ocfs2_do_flock(file, inode, cmd, fl); | |
131 | } | |
53da4939 MF |
132 | |
133 | int ocfs2_lock(struct file *file, int cmd, struct file_lock *fl) | |
134 | { | |
135 | struct inode *inode = file->f_mapping->host; | |
136 | struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); | |
137 | ||
138 | if (!(fl->fl_flags & FL_POSIX)) | |
139 | return -ENOLCK; | |
ee860b6a | 140 | if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK) |
53da4939 MF |
141 | return -ENOLCK; |
142 | ||
143 | return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl); | |
144 | } |