[linux.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.
		 */

		locks_lock_file_wait(file,
				&(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);
}
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
4f656367	69	locks_lock_file_wait(file,
b5a8bc33 JB	70	&(struct file_lock) {
	71	.fl_type = F_UNLCK,
	72	.fl_flags = FL_FLOCK
	73	});
53fc622b MF	74
	75	ocfs2_file_unlock(file);
	76	}
	77
	78	ret = ocfs2_file_lock(file, level, trylock);
	79	if (ret) {
	80	if (ret == -EAGAIN && trylock)
	81	ret = -EWOULDBLOCK;
	82	else
	83	mlog_errno(ret);
	84	goto out;
	85	}
	86
4f656367	87	ret = locks_lock_file_wait(file, fl);
e228f643 WW	88	if (ret)
e228f643 WW	89	ocfs2_file_unlock(file);
53fc622b MF	90
	91	out:
	92	mutex_unlock(&fp->fp_mutex);
	93
	94	return ret;
	95	}
	96
	97	static int ocfs2_do_funlock(struct file file, int cmd, struct file_lock fl)
	98	{
	99	int ret;
	100	struct ocfs2_file_private *fp = file->private_data;
	101
	102	mutex_lock(&fp->fp_mutex);
	103	ocfs2_file_unlock(file);
4f656367	104	ret = locks_lock_file_wait(file, fl);
53fc622b MF	105	mutex_unlock(&fp->fp_mutex);
	106
	107	return ret;
	108	}
	109
	110	/*
	111	* Overall flow of ocfs2_flock() was influenced by gfs2_flock().
	112	*/
	113	int ocfs2_flock(struct file file, int cmd, struct file_lock fl)
	114	{
	115	struct inode *inode = file->f_mapping->host;
	116	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
	117
	118	if (!(fl->fl_flags & FL_FLOCK))
	119	return -ENOLCK;
	120	if (__mandatory_lock(inode))
	121	return -ENOLCK;
	122
	123	if ((osb->s_mount_opt & OCFS2_MOUNT_LOCALFLOCKS) \|\|
	124	ocfs2_mount_local(osb))
4f656367	125	return locks_lock_file_wait(file, fl);
53fc622b MF	126
	127	if (fl->fl_type == F_UNLCK)
	128	return ocfs2_do_funlock(file, cmd, fl);
	129	else
	130	return ocfs2_do_flock(file, inode, cmd, fl);
	131	}
53da4939 MF	132
	133	int ocfs2_lock(struct file file, int cmd, struct file_lock fl)
	134	{
	135	struct inode *inode = file->f_mapping->host;
	136	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
	137
	138	if (!(fl->fl_flags & FL_POSIX))
	139	return -ENOLCK;
ee860b6a	140	if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
53da4939 MF	141	return -ENOLCK;
	142
	143	return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl);
	144	}