path: root/fs/overlayfs/util.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2011 Novell Inc.
 * Copyright (C) 2016 Red Hat, Inc.
 */

#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/slab.h>
#include <linux/cred.h>
#include <linux/xattr.h>
#include <linux/exportfs.h>
#include <linux/file.h>
#include <linux/fileattr.h>
#include <linux/uuid.h>
#include <linux/namei.h>
#include <linux/ratelimit.h>
#include "overlayfs.h"

/* Get write access to upper mnt - may fail if upper sb was remounted ro */
int ovl_get_write_access(struct dentry *dentry)
{
	struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
	return mnt_get_write_access(ovl_upper_mnt(ofs));
}

/* Get write access to upper sb - may block if upper sb is frozen */
void ovl_start_write(struct dentry *dentry)
{
	struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
	sb_start_write(ovl_upper_mnt(ofs)->mnt_sb);
}

int ovl_want_write(struct dentry *dentry)
{
	struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
	return mnt_want_write(ovl_upper_mnt(ofs));
}

void ovl_put_write_access(struct dentry *dentry)
{
	struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
	mnt_put_write_access(ovl_upper_mnt(ofs));
}

void ovl_end_write(struct dentry *dentry)
{
	struct ovl_fs *ofs <