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328970de | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
53fc622b MF |
2 | /* -*- mode: c; c-basic-offset: 8; -*- |
3 | * vim: noexpandtab sw=8 ts=8 sts=0: | |
4 | * | |
5 | * locks.c | |
6 | * | |
7 | * Userspace file locking support | |
8 | * | |
9 | * Copyright (C) 2007 Oracle. All rights reserved. | |
53fc622b MF |
10 | */ |
11 | ||
12 | #include <linux/fs.h> | |
53da4939 | 13 | #include <linux/fcntl.h> |
53fc622b | 14 | |
53fc622b MF |
15 | #include <cluster/masklog.h> |
16 | ||
17 | #include "ocfs2.h" | |
18 | ||
19 | #include "dlmglue.h" | |
20 | #include "file.h" | |
53da4939 | 21 | #include "inode.h" |
53fc622b MF |
22 | #include "locks.h" |
23 | ||
24 | static int ocfs2_do_flock(struct file *file, struct inode *inode, | |
25 | int cmd, struct file_lock *fl) | |
26 | { | |
27 | int ret = 0, level = 0, trylock = 0; | |
28 | struct ocfs2_file_private *fp = file->private_data; | |
29 | struct ocfs2_lock_res *lockres = &fp->fp_flock; | |
30 | ||
31 | if (fl->fl_type == F_WRLCK) | |
32 | level = 1; | |
33 | if (!IS_SETLKW(cmd)) | |
34 | trylock = 1; | |
35 | ||
36 | mutex_lock(&fp->fp_mutex); | |
37 | ||
38 | if (lockres->l_flags & OCFS2_LOCK_ATTACHED && | |
39 | lockres->l_level > LKM_NLMODE) { | |
40 | int old_level = 0; | |
4316c3c6 | 41 | struct file_lock request; |
53fc622b MF |
42 | |
43 | if (lockres->l_level == LKM_EXMODE) | |
44 | old_level = 1; | |
45 | ||
46 | if (level == old_level) | |
47 | goto out; | |
48 | ||
49 | /* | |
50 | * Converting an existing lock is not guaranteed to be | |
51 | * atomic, so we can get away with simply unlocking | |
52 | * here and allowing the lock code to try at the new | |
53 | * level. | |
54 | */ | |
55 | ||
4316c3c6 N |
56 | locks_init_lock(&request); |
57 | request.fl_type = F_UNLCK; | |
58 | request.fl_flags = FL_FLOCK; | |
59 | locks_lock_file_wait(file, &request); | |
53fc622b MF |
60 | |
61 | ocfs2_file_unlock(file); | |
62 | } | |
63 | ||
64 | ret = ocfs2_file_lock(file, level, trylock); | |
65 | if (ret) { | |
66 | if (ret == -EAGAIN && trylock) | |
67 | ret = -EWOULDBLOCK; | |
68 | else | |
69 | mlog_errno(ret); | |
70 | goto out; | |
71 | } | |
72 | ||
4f656367 | 73 | ret = locks_lock_file_wait(file, fl); |
e228f643 WW |
74 | if (ret) |
75 | ocfs2_file_unlock(file); | |
53fc622b MF |
76 | |
77 | out: | |
78 | mutex_unlock(&fp->fp_mutex); | |
79 | ||
80 | return ret; | |
81 | } | |
82 | ||
83 | static int ocfs2_do_funlock(struct file *file, int cmd, struct file_lock *fl) | |
84 | { | |
85 | int ret; | |
86 | struct ocfs2_file_private *fp = file->private_data; | |
87 | ||
88 | mutex_lock(&fp->fp_mutex); | |
89 | ocfs2_file_unlock(file); | |
4f656367 | 90 | ret = locks_lock_file_wait(file, fl); |
53fc622b MF |
91 | mutex_unlock(&fp->fp_mutex); |
92 | ||
93 | return ret; | |
94 | } | |
95 | ||
96 | /* | |
97 | * Overall flow of ocfs2_flock() was influenced by gfs2_flock(). | |
98 | */ | |
99 | int ocfs2_flock(struct file *file, int cmd, struct file_lock *fl) | |
100 | { | |
101 | struct inode *inode = file->f_mapping->host; | |
102 | struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); | |
103 | ||
104 | if (!(fl->fl_flags & FL_FLOCK)) | |
105 | return -ENOLCK; | |
106 | if (__mandatory_lock(inode)) | |
107 | return -ENOLCK; | |
108 | ||
109 | if ((osb->s_mount_opt & OCFS2_MOUNT_LOCALFLOCKS) || | |
110 | ocfs2_mount_local(osb)) | |
4f656367 | 111 | return locks_lock_file_wait(file, fl); |
53fc622b MF |
112 | |
113 | if (fl->fl_type == F_UNLCK) | |
114 | return ocfs2_do_funlock(file, cmd, fl); | |
115 | else | |
116 | return ocfs2_do_flock(file, inode, cmd, fl); | |
117 | } | |
53da4939 MF |
118 | |
119 | int ocfs2_lock(struct file *file, int cmd, struct file_lock *fl) | |
120 | { | |
121 | struct inode *inode = file->f_mapping->host; | |
122 | struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); | |
123 | ||
124 | if (!(fl->fl_flags & FL_POSIX)) | |
125 | return -ENOLCK; | |
ee860b6a | 126 | if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK) |
53da4939 MF |
127 | return -ENOLCK; |
128 | ||
129 | return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl); | |
130 | } |