141 lines
3.4 KiB
C
141 lines
3.4 KiB
C
|
/* -*- 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>
|
||
|
|
|
||
|
|
#define MLOG_MASK_PREFIX ML_INODE
|
||
|
|
#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.
|
||
|
|
*/
|
||
|
|
|
||
|
|
flock_lock_file_wait(file,
|
||
|
|
&(struct file_lock){.fl_type = F_UNLCK});
|
||
|
|
|
||
|
|
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 = flock_lock_file_wait(file, fl);
|
||
|
|
|
||
|
|
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 = flock_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 flock_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))
|
||
|
|
return -ENOLCK;
|
||
|
|
|
||
|
|
return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl);
|
||
|
|
}
|