[linux-2.6-block.git] / fs / ocfs2 / locks.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>

#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) && fl->fl_type != F_UNLCK)
		return -ENOLCK;

	return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl);
}
Commit	Line	Data
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	28
53fc622b MF	29	#include <cluster/masklog.h>
	30
	31	#include "ocfs2.h"
	32
	33	#include "dlmglue.h"
	34	#include "file.h"
53da4939	35	#include "inode.h"
53fc622b MF	36	#include "locks.h"
	37
	38	static int ocfs2_do_flock(struct file file, struct inode inode,
	39	int cmd, struct file_lock *fl)
	40	{
	41	int ret = 0, level = 0, trylock = 0;
	42	struct ocfs2_file_private *fp = file->private_data;
	43	struct ocfs2_lock_res *lockres = &fp->fp_flock;
	44
	45	if (fl->fl_type == F_WRLCK)
	46	level = 1;
	47	if (!IS_SETLKW(cmd))
	48	trylock = 1;
	49
	50	mutex_lock(&fp->fp_mutex);
	51
	52	if (lockres->l_flags & OCFS2_LOCK_ATTACHED &&
	53	lockres->l_level > LKM_NLMODE) {
	54	int old_level = 0;
	55
	56	if (lockres->l_level == LKM_EXMODE)
	57	old_level = 1;
	58
	59	if (level == old_level)
	60	goto out;
	61
	62	/*
	63	* Converting an existing lock is not guaranteed to be
	64	* atomic, so we can get away with simply unlocking
	65	* here and allowing the lock code to try at the new
	66	* level.
	67	*/
	68
	69	flock_lock_file_wait(file,
	70	&(struct file_lock){.fl_type = F_UNLCK});
	71
	72	ocfs2_file_unlock(file);
	73	}
	74
	75	ret = ocfs2_file_lock(file, level, trylock);
	76	if (ret) {
	77	if (ret == -EAGAIN && trylock)
	78	ret = -EWOULDBLOCK;
	79	else
	80	mlog_errno(ret);
	81	goto out;
	82	}
	83
	84	ret = flock_lock_file_wait(file, fl);
	85
	86	out:
	87	mutex_unlock(&fp->fp_mutex);
	88
	89	return ret;
	90	}
	91
	92	static int ocfs2_do_funlock(struct file file, int cmd, struct file_lock fl)
	93	{
	94	int ret;
	95	struct ocfs2_file_private *fp = file->private_data;
	96
	97	mutex_lock(&fp->fp_mutex);
	98	ocfs2_file_unlock(file);
	99	ret = flock_lock_file_wait(file, fl);
100	mutex_unlock(&fp->fp_mutex);
101
102	return ret;
103	}
104
105	/*
106	* Overall flow of ocfs2_flock() was influenced by gfs2_flock().
107	*/
108	int ocfs2_flock(struct file file, int cmd, struct file_lock fl)
109	{
110	struct inode *inode = file->f_mapping->host;
111	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
112
113	if (!(fl->fl_flags & FL_FLOCK))
114	return -ENOLCK;
115	if (__mandatory_lock(inode))
116	return -ENOLCK;
117
118	if ((osb->s_mount_opt & OCFS2_MOUNT_LOCALFLOCKS) \|\|
119	ocfs2_mount_local(osb))
120	return flock_lock_file_wait(file, fl);
121
122	if (fl->fl_type == F_UNLCK)
123	return ocfs2_do_funlock(file, cmd, fl);
124	else
125	return ocfs2_do_flock(file, inode, cmd, fl);
126	}
53da4939 MF	127
	128	int ocfs2_lock(struct file file, int cmd, struct file_lock fl)
	129	{
	130	struct inode *inode = file->f_mapping->host;
	131	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
	132
	133	if (!(fl->fl_flags & FL_POSIX))
	134	return -ENOLCK;
ee860b6a	135	if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
53da4939 MF	136	return -ENOLCK;
	137
	138	return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl);
	139	}