[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/filelock.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 (lock_is_write(fl))
		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.c.flc_type = F_UNLCK;
		request.c.flc_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->c.flc_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 (lock_is_unlock(fl))
		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->c.flc_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>
5970e15d	11	#include <linux/filelock.h>
53da4939	12	#include <linux/fcntl.h>
53fc622b	13
53fc622b MF	14	#include <cluster/masklog.h>
	15
	16	#include "ocfs2.h"
	17
	18	#include "dlmglue.h"
	19	#include "file.h"
53da4939	20	#include "inode.h"
53fc622b MF	21	#include "locks.h"
	22
	23	static int ocfs2_do_flock(struct file file, struct inode inode,
	24	int cmd, struct file_lock *fl)
	25	{
	26	int ret = 0, level = 0, trylock = 0;
	27	struct ocfs2_file_private *fp = file->private_data;
	28	struct ocfs2_lock_res *lockres = &fp->fp_flock;
	29
64f92a55	30	if (lock_is_write(fl))
53fc622b MF	31	level = 1;
	32	if (!IS_SETLKW(cmd))
	33	trylock = 1;
	34
	35	mutex_lock(&fp->fp_mutex);
	36
	37	if (lockres->l_flags & OCFS2_LOCK_ATTACHED &&
	38	lockres->l_level > LKM_NLMODE) {
	39	int old_level = 0;
4316c3c6	40	struct file_lock request;
53fc622b MF	41
	42	if (lockres->l_level == LKM_EXMODE)
	43	old_level = 1;
	44
	45	if (level == old_level)
	46	goto out;
	47
	48	/*
	49	* Converting an existing lock is not guaranteed to be
	50	* atomic, so we can get away with simply unlocking
	51	* here and allowing the lock code to try at the new
	52	* level.
	53	*/
	54
4316c3c6	55	locks_init_lock(&request);
c8df2cc9 JL	56	request.c.flc_type = F_UNLCK;
c8df2cc9 JL	57	request.c.flc_flags = FL_FLOCK;
4316c3c6	58	locks_lock_file_wait(file, &request);
53fc622b MF	59
	60	ocfs2_file_unlock(file);
	61	}
	62
	63	ret = ocfs2_file_lock(file, level, trylock);
	64	if (ret) {
	65	if (ret == -EAGAIN && trylock)
	66	ret = -EWOULDBLOCK;
	67	else
	68	mlog_errno(ret);
	69	goto out;
	70	}
	71
4f656367	72	ret = locks_lock_file_wait(file, fl);
e228f643 WW	73	if (ret)
e228f643 WW	74	ocfs2_file_unlock(file);
53fc622b MF	75
	76	out:
	77	mutex_unlock(&fp->fp_mutex);
	78
	79	return ret;
	80	}
	81
	82	static int ocfs2_do_funlock(struct file file, int cmd, struct file_lock fl)
	83	{
	84	int ret;
	85	struct ocfs2_file_private *fp = file->private_data;
	86
	87	mutex_lock(&fp->fp_mutex);
	88	ocfs2_file_unlock(file);
4f656367	89	ret = locks_lock_file_wait(file, fl);
53fc622b MF	90	mutex_unlock(&fp->fp_mutex);
	91
	92	return ret;
	93	}
	94
	95	/*
	96	* Overall flow of ocfs2_flock() was influenced by gfs2_flock().
	97	*/
	98	int ocfs2_flock(struct file file, int cmd, struct file_lock fl)
	99	{
	100	struct inode *inode = file->f_mapping->host;
	101	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
	102
c8df2cc9	103	if (!(fl->c.flc_flags & FL_FLOCK))
53fc622b	104	return -ENOLCK;
53fc622b MF	105
	106	if ((osb->s_mount_opt & OCFS2_MOUNT_LOCALFLOCKS) \|\|
	107	ocfs2_mount_local(osb))
4f656367	108	return locks_lock_file_wait(file, fl);
53fc622b	109
64f92a55	110	if (lock_is_unlock(fl))
53fc622b MF	111	return ocfs2_do_funlock(file, cmd, fl);
	112	else
	113	return ocfs2_do_flock(file, inode, cmd, fl);
	114	}
53da4939 MF	115
	116	int ocfs2_lock(struct file file, int cmd, struct file_lock fl)
	117	{
	118	struct inode *inode = file->f_mapping->host;
	119	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
	120
c8df2cc9	121	if (!(fl->c.flc_flags & FL_POSIX))
53da4939	122	return -ENOLCK;
53da4939 MF	123
	124	return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl);
	125	}