fs/aufs/hfsplus.c

/*
 * Copyright (C) 2010-2013 Junjiro R. Okajima
 *
 * This program, aufs 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

/*
 * special support for filesystems which aqucires an inode mutex
 * at final closing a file, eg, hfsplus.
 *
 * This trick is very simple and stupid, just to open the file before really
 * neceeary open to tell hfsplus that this is not the final closing.
 * The caller should call au_h_open_pre() after acquiring the inode mutex,
 * and au_h_open_post() after releasing it.
 */

#include "aufs.h"

struct file *au_h_open_pre(struct dentry *dentry, aufs_bindex_t bindex)
{
	struct file *h_file;
	struct dentry *h_dentry;

	h_dentry = au_h_dptr(dentry, bindex);
	AuDebugOn(!h_dentry);
	AuDebugOn(!h_dentry->d_inode);

	h_file = NULL;
	if (au_test_hfsplus(h_dentry->d_sb)
	    && S_ISREG(h_dentry->d_inode->i_mode))
		h_file = au_h_open(dentry, bindex,
				   O_RDONLY | O_NOATIME | O_LARGEFILE,
				   /*file*/NULL);
	return h_file;
}

void au_h_open_post(struct dentry *dentry, aufs_bindex_t bindex,
		    struct file *h_file)
{
	if (h_file) {
		fput(h_file);
		au_sbr_put(dentry->d_sb, bindex);
	}
}