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

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * locks.c
 *
 * Userspace file locking support
 *
 * Copyright (C) 2007 Oracle.  All rights reserved.
 */

#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;
		struct file_lock request;

		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_init_lock(&request);
		request.fl_type = F_UNLCK;
		request.fl_flags = FL_FLOCK;
		locks_lock_file_wait(file, &request);

		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 ((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;

	return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl);
}
Commit	Line	Data
328970de	1	// SPDX-License-Identifier: GPL-2.0-or-later
fa60ce2c	2	/*
53fc622b MF	3	* locks.c
	4	*
	5	* Userspace file locking support
	6	*
	7	* Copyright (C) 2007 Oracle. All rights reserved.
53fc622b MF	8	*/
	9
	10	#include <linux/fs.h>
53da4939	11	#include <linux/fcntl.h>
53fc622b	12
53fc622b MF	13	#include <cluster/masklog.h>
	14
	15	#include "ocfs2.h"
	16
	17	#include "dlmglue.h"
	18	#include "file.h"
53da4939	19	#include "inode.h"
53fc622b MF	20	#include "locks.h"
	21
	22	static int ocfs2_do_flock(struct file file, struct inode inode,
	23	int cmd, struct file_lock *fl)
	24	{
	25	int ret = 0, level = 0, trylock = 0;
	26	struct ocfs2_file_private *fp = file->private_data;
	27	struct ocfs2_lock_res *lockres = &fp->fp_flock;
	28
	29	if (fl->fl_type == F_WRLCK)
	30	level = 1;
	31	if (!IS_SETLKW(cmd))
	32	trylock = 1;
	33
	34	mutex_lock(&fp->fp_mutex);
	35
	36	if (lockres->l_flags & OCFS2_LOCK_ATTACHED &&
	37	lockres->l_level > LKM_NLMODE) {
	38	int old_level = 0;
4316c3c6	39	struct file_lock request;
53fc622b MF	40
	41	if (lockres->l_level == LKM_EXMODE)
	42	old_level = 1;
	43
	44	if (level == old_level)
	45	goto out;
	46
	47	/*
	48	* Converting an existing lock is not guaranteed to be
	49	* atomic, so we can get away with simply unlocking
	50	* here and allowing the lock code to try at the new
	51	* level.
	52	*/
	53
4316c3c6 N	54	locks_init_lock(&request);
	55	request.fl_type = F_UNLCK;
	56	request.fl_flags = FL_FLOCK;
	57	locks_lock_file_wait(file, &request);
53fc622b MF	58
	59	ocfs2_file_unlock(file);
	60	}
	61
	62	ret = ocfs2_file_lock(file, level, trylock);
	63	if (ret) {
	64	if (ret == -EAGAIN && trylock)
	65	ret = -EWOULDBLOCK;
	66	else
	67	mlog_errno(ret);
	68	goto out;
	69	}
	70
4f656367	71	ret = locks_lock_file_wait(file, fl);
e228f643 WW	72	if (ret)
e228f643 WW	73	ocfs2_file_unlock(file);
53fc622b MF	74
	75	out:
	76	mutex_unlock(&fp->fp_mutex);
	77
	78	return ret;
	79	}
	80
	81	static int ocfs2_do_funlock(struct file file, int cmd, struct file_lock fl)
	82	{
	83	int ret;
	84	struct ocfs2_file_private *fp = file->private_data;
	85
	86	mutex_lock(&fp->fp_mutex);
	87	ocfs2_file_unlock(file);
4f656367	88	ret = locks_lock_file_wait(file, fl);
53fc622b MF	89	mutex_unlock(&fp->fp_mutex);
	90
	91	return ret;
	92	}
	93
	94	/*
	95	* Overall flow of ocfs2_flock() was influenced by gfs2_flock().
	96	*/
	97	int ocfs2_flock(struct file file, int cmd, struct file_lock fl)
	98	{
	99	struct inode *inode = file->f_mapping->host;
	100	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
	101
	102	if (!(fl->fl_flags & FL_FLOCK))
	103	return -ENOLCK;
53fc622b MF	104
	105	if ((osb->s_mount_opt & OCFS2_MOUNT_LOCALFLOCKS) \|\|
	106	ocfs2_mount_local(osb))
4f656367	107	return locks_lock_file_wait(file, fl);
53fc622b MF	108
	109	if (fl->fl_type == F_UNLCK)
	110	return ocfs2_do_funlock(file, cmd, fl);
	111	else
	112	return ocfs2_do_flock(file, inode, cmd, fl);
	113	}
53da4939 MF	114
	115	int ocfs2_lock(struct file file, int cmd, struct file_lock fl)
	116	{
	117	struct inode *inode = file->f_mapping->host;
	118	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
	119
	120	if (!(fl->fl_flags & FL_POSIX))
	121	return -ENOLCK;
53da4939 MF	122
	123	return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl);
	124	}