1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-or-later
2*4882a593Smuzhiyun /* -*- mode: c; c-basic-offset: 8; -*-
3*4882a593Smuzhiyun * vim: noexpandtab sw=8 ts=8 sts=0:
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * locks.c
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * Userspace file locking support
8*4882a593Smuzhiyun *
9*4882a593Smuzhiyun * Copyright (C) 2007 Oracle. All rights reserved.
10*4882a593Smuzhiyun */
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun #include <linux/fs.h>
13*4882a593Smuzhiyun #include <linux/fcntl.h>
14*4882a593Smuzhiyun
15*4882a593Smuzhiyun #include <cluster/masklog.h>
16*4882a593Smuzhiyun
17*4882a593Smuzhiyun #include "ocfs2.h"
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun #include "dlmglue.h"
20*4882a593Smuzhiyun #include "file.h"
21*4882a593Smuzhiyun #include "inode.h"
22*4882a593Smuzhiyun #include "locks.h"
23*4882a593Smuzhiyun
ocfs2_do_flock(struct file * file,struct inode * inode,int cmd,struct file_lock * fl)24*4882a593Smuzhiyun static int ocfs2_do_flock(struct file *file, struct inode *inode,
25*4882a593Smuzhiyun int cmd, struct file_lock *fl)
26*4882a593Smuzhiyun {
27*4882a593Smuzhiyun int ret = 0, level = 0, trylock = 0;
28*4882a593Smuzhiyun struct ocfs2_file_private *fp = file->private_data;
29*4882a593Smuzhiyun struct ocfs2_lock_res *lockres = &fp->fp_flock;
30*4882a593Smuzhiyun
31*4882a593Smuzhiyun if (fl->fl_type == F_WRLCK)
32*4882a593Smuzhiyun level = 1;
33*4882a593Smuzhiyun if (!IS_SETLKW(cmd))
34*4882a593Smuzhiyun trylock = 1;
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun mutex_lock(&fp->fp_mutex);
37*4882a593Smuzhiyun
38*4882a593Smuzhiyun if (lockres->l_flags & OCFS2_LOCK_ATTACHED &&
39*4882a593Smuzhiyun lockres->l_level > LKM_NLMODE) {
40*4882a593Smuzhiyun int old_level = 0;
41*4882a593Smuzhiyun struct file_lock request;
42*4882a593Smuzhiyun
43*4882a593Smuzhiyun if (lockres->l_level == LKM_EXMODE)
44*4882a593Smuzhiyun old_level = 1;
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun if (level == old_level)
47*4882a593Smuzhiyun goto out;
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun /*
50*4882a593Smuzhiyun * Converting an existing lock is not guaranteed to be
51*4882a593Smuzhiyun * atomic, so we can get away with simply unlocking
52*4882a593Smuzhiyun * here and allowing the lock code to try at the new
53*4882a593Smuzhiyun * level.
54*4882a593Smuzhiyun */
55*4882a593Smuzhiyun
56*4882a593Smuzhiyun locks_init_lock(&request);
57*4882a593Smuzhiyun request.fl_type = F_UNLCK;
58*4882a593Smuzhiyun request.fl_flags = FL_FLOCK;
59*4882a593Smuzhiyun locks_lock_file_wait(file, &request);
60*4882a593Smuzhiyun
61*4882a593Smuzhiyun ocfs2_file_unlock(file);
62*4882a593Smuzhiyun }
63*4882a593Smuzhiyun
64*4882a593Smuzhiyun ret = ocfs2_file_lock(file, level, trylock);
65*4882a593Smuzhiyun if (ret) {
66*4882a593Smuzhiyun if (ret == -EAGAIN && trylock)
67*4882a593Smuzhiyun ret = -EWOULDBLOCK;
68*4882a593Smuzhiyun else
69*4882a593Smuzhiyun mlog_errno(ret);
70*4882a593Smuzhiyun goto out;
71*4882a593Smuzhiyun }
72*4882a593Smuzhiyun
73*4882a593Smuzhiyun ret = locks_lock_file_wait(file, fl);
74*4882a593Smuzhiyun if (ret)
75*4882a593Smuzhiyun ocfs2_file_unlock(file);
76*4882a593Smuzhiyun
77*4882a593Smuzhiyun out:
78*4882a593Smuzhiyun mutex_unlock(&fp->fp_mutex);
79*4882a593Smuzhiyun
80*4882a593Smuzhiyun return ret;
81*4882a593Smuzhiyun }
82*4882a593Smuzhiyun
ocfs2_do_funlock(struct file * file,int cmd,struct file_lock * fl)83*4882a593Smuzhiyun static int ocfs2_do_funlock(struct file *file, int cmd, struct file_lock *fl)
84*4882a593Smuzhiyun {
85*4882a593Smuzhiyun int ret;
86*4882a593Smuzhiyun struct ocfs2_file_private *fp = file->private_data;
87*4882a593Smuzhiyun
88*4882a593Smuzhiyun mutex_lock(&fp->fp_mutex);
89*4882a593Smuzhiyun ocfs2_file_unlock(file);
90*4882a593Smuzhiyun ret = locks_lock_file_wait(file, fl);
91*4882a593Smuzhiyun mutex_unlock(&fp->fp_mutex);
92*4882a593Smuzhiyun
93*4882a593Smuzhiyun return ret;
94*4882a593Smuzhiyun }
95*4882a593Smuzhiyun
96*4882a593Smuzhiyun /*
97*4882a593Smuzhiyun * Overall flow of ocfs2_flock() was influenced by gfs2_flock().
98*4882a593Smuzhiyun */
ocfs2_flock(struct file * file,int cmd,struct file_lock * fl)99*4882a593Smuzhiyun int ocfs2_flock(struct file *file, int cmd, struct file_lock *fl)
100*4882a593Smuzhiyun {
101*4882a593Smuzhiyun struct inode *inode = file->f_mapping->host;
102*4882a593Smuzhiyun struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
103*4882a593Smuzhiyun
104*4882a593Smuzhiyun if (!(fl->fl_flags & FL_FLOCK))
105*4882a593Smuzhiyun return -ENOLCK;
106*4882a593Smuzhiyun if (__mandatory_lock(inode))
107*4882a593Smuzhiyun return -ENOLCK;
108*4882a593Smuzhiyun
109*4882a593Smuzhiyun if ((osb->s_mount_opt & OCFS2_MOUNT_LOCALFLOCKS) ||
110*4882a593Smuzhiyun ocfs2_mount_local(osb))
111*4882a593Smuzhiyun return locks_lock_file_wait(file, fl);
112*4882a593Smuzhiyun
113*4882a593Smuzhiyun if (fl->fl_type == F_UNLCK)
114*4882a593Smuzhiyun return ocfs2_do_funlock(file, cmd, fl);
115*4882a593Smuzhiyun else
116*4882a593Smuzhiyun return ocfs2_do_flock(file, inode, cmd, fl);
117*4882a593Smuzhiyun }
118*4882a593Smuzhiyun
ocfs2_lock(struct file * file,int cmd,struct file_lock * fl)119*4882a593Smuzhiyun int ocfs2_lock(struct file *file, int cmd, struct file_lock *fl)
120*4882a593Smuzhiyun {
121*4882a593Smuzhiyun struct inode *inode = file->f_mapping->host;
122*4882a593Smuzhiyun struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
123*4882a593Smuzhiyun
124*4882a593Smuzhiyun if (!(fl->fl_flags & FL_POSIX))
125*4882a593Smuzhiyun return -ENOLCK;
126*4882a593Smuzhiyun if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
127*4882a593Smuzhiyun return -ENOLCK;
128*4882a593Smuzhiyun
129*4882a593Smuzhiyun return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl);
130*4882a593Smuzhiyun }
131