linux/fs/ocfs2/locks.c

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/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* locks.c
*
* Userspace file locking support
*
* Copyright (C) 2007 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <linux/fs.h>
#include <linux/fcntl.h>
#include <cluster/masklog.h>
#include "ocfs2.h"
#include "dlmglue.h"
#include "file.h"
#include "inode.h"
#include "locks.h"
static int ocfs2_do_flock(struct file *file, struct inode *inode,
int cmd, struct file_lock *fl)
{
int ret = 0, level = 0, trylock = 0;
struct ocfs2_file_private *fp = file->private_data;
struct ocfs2_lock_res *lockres = &fp->fp_flock;
if (fl->fl_type == F_WRLCK)
level = 1;
if (!IS_SETLKW(cmd))
trylock = 1;
mutex_lock(&fp->fp_mutex);
if (lockres->l_flags & OCFS2_LOCK_ATTACHED &&
lockres->l_level > LKM_NLMODE) {
int old_level = 0;
if (lockres->l_level == LKM_EXMODE)
old_level = 1;
if (level == old_level)
goto out;
/*
* Converting an existing lock is not guaranteed to be
* atomic, so we can get away with simply unlocking
* here and allowing the lock code to try at the new
* level.
*/
locks_lock_file_wait(file,
ocfs2: fix flock panic issue Commit 4f6563677ae8 ("Move locks API users to locks_lock_inode_wait()") move flock/posix lock indentify code to locks_lock_inode_wait(), but missed to set fl_flags to FL_FLOCK which caused the following kernel panic on 4.4.0_rc5. kernel BUG at fs/locks.c:1895! invalid opcode: 0000 [#1] SMP Modules linked in: ocfs2(O) ocfs2_dlmfs(O) ocfs2_stack_o2cb(O) ocfs2_dlm(O) ocfs2_nodemanager(O) ocfs2_stackglue(O) iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi xen_kbdfront xen_netfront xen_fbfront xen_blkfront CPU: 0 PID: 20268 Comm: flock_unit_test Tainted: G O 4.4.0-rc5-next-20151217 #1 Hardware name: Xen HVM domU, BIOS 4.3.1OVM 05/14/2014 task: ffff88007b3672c0 ti: ffff880028b58000 task.ti: ffff880028b58000 RIP: locks_lock_inode_wait+0x2e/0x160 Call Trace: ocfs2_do_flock+0x91/0x160 [ocfs2] ocfs2_flock+0x76/0xd0 [ocfs2] SyS_flock+0x10f/0x1a0 entry_SYSCALL_64_fastpath+0x12/0x71 Code: e5 41 57 41 56 49 89 fe 41 55 41 54 53 48 89 f3 48 81 ec 88 00 00 00 8b 46 40 83 e0 03 83 f8 01 0f 84 ad 00 00 00 83 f8 02 74 04 <0f> 0b eb fe 4c 8d ad 60 ff ff ff 4c 8d 7b 58 e8 0e 8e 73 00 4d RIP locks_lock_inode_wait+0x2e/0x160 RSP <ffff880028b5bce8> ---[ end trace dfca74ec9b5b274c ]--- Fixes: 4f6563677ae8 ("Move locks API users to locks_lock_inode_wait()") Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com> Cc: Mark Fasheh <mfasheh@suse.de> Cc: Joel Becker <jlbec@evilplan.org> Cc: Joseph Qi <joseph.qi@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-12-29 22:54:22 +00:00
&(struct file_lock) {
.fl_type = F_UNLCK,
.fl_flags = FL_FLOCK
});
ocfs2_file_unlock(file);
}
ret = ocfs2_file_lock(file, level, trylock);
if (ret) {
if (ret == -EAGAIN && trylock)
ret = -EWOULDBLOCK;
else
mlog_errno(ret);
goto out;
}
ret = locks_lock_file_wait(file, fl);
if (ret)
ocfs2_file_unlock(file);
out:
mutex_unlock(&fp->fp_mutex);
return ret;
}
static int ocfs2_do_funlock(struct file *file, int cmd, struct file_lock *fl)
{
int ret;
struct ocfs2_file_private *fp = file->private_data;
mutex_lock(&fp->fp_mutex);
ocfs2_file_unlock(file);
ret = locks_lock_file_wait(file, fl);
mutex_unlock(&fp->fp_mutex);
return ret;
}
/*
* Overall flow of ocfs2_flock() was influenced by gfs2_flock().
*/
int ocfs2_flock(struct file *file, int cmd, struct file_lock *fl)
{
struct inode *inode = file->f_mapping->host;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
if (!(fl->fl_flags & FL_FLOCK))
return -ENOLCK;
if (__mandatory_lock(inode))
return -ENOLCK;
if ((osb->s_mount_opt & OCFS2_MOUNT_LOCALFLOCKS) ||
ocfs2_mount_local(osb))
return locks_lock_file_wait(file, fl);
if (fl->fl_type == F_UNLCK)
return ocfs2_do_funlock(file, cmd, fl);
else
return ocfs2_do_flock(file, inode, cmd, fl);
}
int ocfs2_lock(struct file *file, int cmd, struct file_lock *fl)
{
struct inode *inode = file->f_mapping->host;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
if (!(fl->fl_flags & FL_POSIX))
return -ENOLCK;
if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
return -ENOLCK;
return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl);
}