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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 MF |
28 | |
29 | #define MLOG_MASK_PREFIX ML_INODE | |
30 | #include <cluster/masklog.h> | |
31 | ||
32 | #include "ocfs2.h" | |
33 | ||
34 | #include "dlmglue.h" | |
35 | #include "file.h" | |
53da4939 | 36 | #include "inode.h" |
53fc622b MF |
37 | #include "locks.h" |
38 | ||
39 | static int ocfs2_do_flock(struct file *file, struct inode *inode, | |
40 | int cmd, struct file_lock *fl) | |
41 | { | |
42 | int ret = 0, level = 0, trylock = 0; | |
43 | struct ocfs2_file_private *fp = file->private_data; | |
44 | struct ocfs2_lock_res *lockres = &fp->fp_flock; | |
45 | ||
46 | if (fl->fl_type == F_WRLCK) | |
47 | level = 1; | |
48 | if (!IS_SETLKW(cmd)) | |
49 | trylock = 1; | |
50 | ||
51 | mutex_lock(&fp->fp_mutex); | |
52 | ||
53 | if (lockres->l_flags & OCFS2_LOCK_ATTACHED && | |
54 | lockres->l_level > LKM_NLMODE) { | |
55 | int old_level = 0; | |
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 | ||
70 | flock_lock_file_wait(file, | |
71 | &(struct file_lock){.fl_type = F_UNLCK}); | |
72 | ||
73 | ocfs2_file_unlock(file); | |
74 | } | |
75 | ||
76 | ret = ocfs2_file_lock(file, level, trylock); | |
77 | if (ret) { | |
78 | if (ret == -EAGAIN && trylock) | |
79 | ret = -EWOULDBLOCK; | |
80 | else | |
81 | mlog_errno(ret); | |
82 | goto out; | |
83 | } | |
84 | ||
85 | ret = flock_lock_file_wait(file, fl); | |
86 | ||
87 | out: | |
88 | mutex_unlock(&fp->fp_mutex); | |
89 | ||
90 | return ret; | |
91 | } | |
92 | ||
93 | static int ocfs2_do_funlock(struct file *file, int cmd, struct file_lock *fl) | |
94 | { | |
95 | int ret; | |
96 | struct ocfs2_file_private *fp = file->private_data; | |
97 | ||
98 | mutex_lock(&fp->fp_mutex); | |
99 | ocfs2_file_unlock(file); | |
100 | ret = flock_lock_file_wait(file, fl); | |
101 | mutex_unlock(&fp->fp_mutex); | |
102 | ||
103 | return ret; | |
104 | } | |
105 | ||
106 | /* | |
107 | * Overall flow of ocfs2_flock() was influenced by gfs2_flock(). | |
108 | */ | |
109 | int ocfs2_flock(struct file *file, int cmd, struct file_lock *fl) | |
110 | { | |
111 | struct inode *inode = file->f_mapping->host; | |
112 | struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); | |
113 | ||
114 | if (!(fl->fl_flags & FL_FLOCK)) | |
115 | return -ENOLCK; | |
116 | if (__mandatory_lock(inode)) | |
117 | return -ENOLCK; | |
118 | ||
119 | if ((osb->s_mount_opt & OCFS2_MOUNT_LOCALFLOCKS) || | |
120 | ocfs2_mount_local(osb)) | |
121 | return flock_lock_file_wait(file, fl); | |
122 | ||
123 | if (fl->fl_type == F_UNLCK) | |
124 | return ocfs2_do_funlock(file, cmd, fl); | |
125 | else | |
126 | return ocfs2_do_flock(file, inode, cmd, fl); | |
127 | } | |
53da4939 MF |
128 | |
129 | int ocfs2_lock(struct file *file, int cmd, struct file_lock *fl) | |
130 | { | |
131 | struct inode *inode = file->f_mapping->host; | |
132 | struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); | |
133 | ||
134 | if (!(fl->fl_flags & FL_POSIX)) | |
135 | return -ENOLCK; | |
136 | if (__mandatory_lock(inode)) | |
137 | return -ENOLCK; | |
138 | ||
139 | return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl); | |
140 | } |