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

// SPDX-License-Identifier: GPL-2.0-or-later
/* -*- 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.
 */

#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 (__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
328970de	1	// SPDX-License-Identifier: GPL-2.0-or-later
53fc622b MF	2	/* -- mode: c; c-basic-offset: 8; --
	3	* vim: noexpandtab sw=8 ts=8 sts=0:
	4	*
	5	* locks.c
	6	*
	7	* Userspace file locking support
	8	*
	9	* Copyright (C) 2007 Oracle. All rights reserved.
53fc622b MF	10	*/
	11
	12	#include <linux/fs.h>
53da4939	13	#include <linux/fcntl.h>
53fc622b	14
53fc622b MF	15	#include <cluster/masklog.h>
	16
	17	#include "ocfs2.h"
	18
	19	#include "dlmglue.h"
	20	#include "file.h"
53da4939	21	#include "inode.h"
53fc622b MF	22	#include "locks.h"
	23
	24	static int ocfs2_do_flock(struct file file, struct inode inode,
	25	int cmd, struct file_lock *fl)
	26	{
	27	int ret = 0, level = 0, trylock = 0;
	28	struct ocfs2_file_private *fp = file->private_data;
	29	struct ocfs2_lock_res *lockres = &fp->fp_flock;
	30
	31	if (fl->fl_type == F_WRLCK)
	32	level = 1;
	33	if (!IS_SETLKW(cmd))
	34	trylock = 1;
	35
	36	mutex_lock(&fp->fp_mutex);
	37
	38	if (lockres->l_flags & OCFS2_LOCK_ATTACHED &&
	39	lockres->l_level > LKM_NLMODE) {
	40	int old_level = 0;
4316c3c6	41	struct file_lock request;
53fc622b MF	42
	43	if (lockres->l_level == LKM_EXMODE)
	44	old_level = 1;
	45
	46	if (level == old_level)
	47	goto out;
	48
	49	/*
	50	* Converting an existing lock is not guaranteed to be
	51	* atomic, so we can get away with simply unlocking
	52	* here and allowing the lock code to try at the new
	53	* level.
	54	*/
	55
4316c3c6 N	56	locks_init_lock(&request);
	57	request.fl_type = F_UNLCK;
	58	request.fl_flags = FL_FLOCK;
	59	locks_lock_file_wait(file, &request);
53fc622b MF	60
	61	ocfs2_file_unlock(file);
	62	}
	63
	64	ret = ocfs2_file_lock(file, level, trylock);
	65	if (ret) {
	66	if (ret == -EAGAIN && trylock)
	67	ret = -EWOULDBLOCK;
	68	else
	69	mlog_errno(ret);
	70	goto out;
	71	}
	72
4f656367	73	ret = locks_lock_file_wait(file, fl);
e228f643 WW	74	if (ret)
e228f643 WW	75	ocfs2_file_unlock(file);
53fc622b MF	76
	77	out:
	78	mutex_unlock(&fp->fp_mutex);
	79
	80	return ret;
	81	}
	82
	83	static int ocfs2_do_funlock(struct file file, int cmd, struct file_lock fl)
	84	{
	85	int ret;
	86	struct ocfs2_file_private *fp = file->private_data;
	87
	88	mutex_lock(&fp->fp_mutex);
	89	ocfs2_file_unlock(file);
4f656367	90	ret = locks_lock_file_wait(file, fl);
53fc622b MF	91	mutex_unlock(&fp->fp_mutex);
	92
	93	return ret;
	94	}
	95
	96	/*
	97	* Overall flow of ocfs2_flock() was influenced by gfs2_flock().
	98	*/
	99	int ocfs2_flock(struct file file, int cmd, struct file_lock fl)
	100	{
	101	struct inode *inode = file->f_mapping->host;
	102	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
	103
	104	if (!(fl->fl_flags & FL_FLOCK))
	105	return -ENOLCK;
	106	if (__mandatory_lock(inode))
	107	return -ENOLCK;
	108
	109	if ((osb->s_mount_opt & OCFS2_MOUNT_LOCALFLOCKS) \|\|
	110	ocfs2_mount_local(osb))
4f656367	111	return locks_lock_file_wait(file, fl);
53fc622b MF	112
	113	if (fl->fl_type == F_UNLCK)
	114	return ocfs2_do_funlock(file, cmd, fl);
	115	else
	116	return ocfs2_do_flock(file, inode, cmd, fl);
	117	}
53da4939 MF	118
	119	int ocfs2_lock(struct file file, int cmd, struct file_lock fl)
	120	{
	121	struct inode *inode = file->f_mapping->host;
	122	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
	123
	124	if (!(fl->fl_flags & FL_POSIX))
	125	return -ENOLCK;
ee860b6a	126	if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
53da4939 MF	127	return -ENOLCK;
	128
	129	return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl);
	130	}