[linux-2.6-block.git] / fs / squashfs / xattr_id.c

/*
 * Squashfs - a compressed read only filesystem for Linux
 *
 * Copyright (c) 2010
 * Phillip Lougher <phillip@squashfs.org.uk>
 *
 * This program 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,
 * 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * xattr_id.c
 */

/*
 * This file implements code to map the 32-bit xattr id stored in the inode
 * into the on disk location of the xattr data.
 */

#include <linux/fs.h>
#include <linux/vfs.h>
#include <linux/slab.h>

#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "squashfs.h"
#include "xattr.h"

/*
 * Map xattr id using the xattr id look up table
 */
int squashfs_xattr_lookup(struct super_block *sb, unsigned int index,
		int *count, unsigned int *size, unsigned long long *xattr)
{
	struct squashfs_sb_info *msblk = sb->s_fs_info;
	int block = SQUASHFS_XATTR_BLOCK(index);
	int offset = SQUASHFS_XATTR_BLOCK_OFFSET(index);
	u64 start_block = le64_to_cpu(msblk->xattr_id_table[block]);
	struct squashfs_xattr_id id;
	int err;

	err = squashfs_read_metadata(sb, &id, &start_block, &offset,
							sizeof(id));
	if (err < 0)
		return err;

	*xattr = le64_to_cpu(id.xattr);
	*size = le32_to_cpu(id.size);
	*count = le32_to_cpu(id.count);
	return 0;
}


/*
 * Read uncompressed xattr id lookup table indexes from disk into memory
 */
__le64 *squashfs_read_xattr_id_table(struct super_block *sb, u64 start,
		u64 *xattr_table_start, int *xattr_ids)
{
	unsigned int len;
	struct squashfs_xattr_id_table *id_table;

	id_table = squashfs_read_table(sb, start, sizeof(*id_table));
	if (IS_ERR(id_table))
		return (__le64 *) id_table;

	*xattr_table_start = le64_to_cpu(id_table->xattr_table_start);
	*xattr_ids = le32_to_cpu(id_table->xattr_ids);
	kfree(id_table);

	/* Sanity check values */

	/* there is always at least one xattr id */
	if (*xattr_ids == 0)
		return ERR_PTR(-EINVAL);

	/* xattr_table should be less than start */
	if (*xattr_table_start >= start)
		return ERR_PTR(-EINVAL);

	len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids);

	TRACE("In read_xattr_index_table, length %d\n", len);

	return squashfs_read_table(sb, start + sizeof(*id_table), len);
}
Commit	Line	Data
4b5397dc PL	1	/*
	2	* Squashfs - a compressed read only filesystem for Linux
	3	*
	4	* Copyright (c) 2010
d7f2ff67	5	* Phillip Lougher <phillip@squashfs.org.uk>
4b5397dc PL	6	*
	7	* This program is free software; you can redistribute it and/or
	8	* modify it under the terms of the GNU General Public License
	9	* as published by the Free Software Foundation; either version 2,
	10	* or (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; if not, write to the Free Software
	19	* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
	20	*
	21	* xattr_id.c
	22	*/
	23
	24	/*
	25	* This file implements code to map the 32-bit xattr id stored in the inode
	26	* into the on disk location of the xattr data.
	27	*/
	28
	29	#include <linux/fs.h>
	30	#include <linux/vfs.h>
	31	#include <linux/slab.h>
	32
	33	#include "squashfs_fs.h"
	34	#include "squashfs_fs_sb.h"
4b5397dc	35	#include "squashfs.h"
5f3b321d	36	#include "xattr.h"
4b5397dc PL	37
	38	/*
	39	* Map xattr id using the xattr id look up table
	40	*/
	41	int squashfs_xattr_lookup(struct super_block *sb, unsigned int index,
aa5b1894	42	int count, unsigned int size, unsigned long long *xattr)
4b5397dc PL	43	{
	44	struct squashfs_sb_info *msblk = sb->s_fs_info;
	45	int block = SQUASHFS_XATTR_BLOCK(index);
	46	int offset = SQUASHFS_XATTR_BLOCK_OFFSET(index);
	47	u64 start_block = le64_to_cpu(msblk->xattr_id_table[block]);
	48	struct squashfs_xattr_id id;
	49	int err;
	50
	51	err = squashfs_read_metadata(sb, &id, &start_block, &offset,
	52	sizeof(id));
	53	if (err < 0)
	54	return err;
	55
	56	*xattr = le64_to_cpu(id.xattr);
	57	*size = le32_to_cpu(id.size);
	58	*count = le32_to_cpu(id.count);
	59	return 0;
	60	}
	61
	62
	63	/*
	64	* Read uncompressed xattr id lookup table indexes from disk into memory
	65	*/
	66	__le64 squashfs_read_xattr_id_table(struct super_block sb, u64 start,
	67	u64 xattr_table_start, int xattr_ids)
	68	{
	69	unsigned int len;
82de647e PL	70	struct squashfs_xattr_id_table *id_table;
	71
	72	id_table = squashfs_read_table(sb, start, sizeof(*id_table));
	73	if (IS_ERR(id_table))
	74	return (__le64 *) id_table;
4b5397dc	75
82de647e PL	76	*xattr_table_start = le64_to_cpu(id_table->xattr_table_start);
	77	*xattr_ids = le32_to_cpu(id_table->xattr_ids);
	78	kfree(id_table);
6f048645 PL	79
	80	/* Sanity check values */
	81
	82	/* there is always at least one xattr id */
	83	if (*xattr_ids == 0)
	84	return ERR_PTR(-EINVAL);
	85
	86	/* xattr_table should be less than start */
	87	if (*xattr_table_start >= start)
	88	return ERR_PTR(-EINVAL);
	89
4b5397dc PL	90	len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids);
	91
	92	TRACE("In read_xattr_index_table, length %d\n", len);
	93
82de647e	94	return squashfs_read_table(sb, start + sizeof(*id_table), len);
4b5397dc	95	}