/*
   * 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
  ", len);

  	return squashfs_read_table(sb, start + sizeof(*id_table), len);

  }