From 4b5397dc24ab12afaac85be3d0863b7f6eb8b0f0 Mon Sep 17 00:00:00 2001 From: Phillip Lougher Date: Fri, 14 May 2010 20:48:47 +0100 Subject: squashfs: add xattr id support This patch adds support for mapping xattr ids (stored in inodes) into the on-disk location of the xattrs themselves. Signed-off-by: Phillip Lougher --- fs/squashfs/xattr_id.c | 100 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 100 insertions(+) create mode 100644 fs/squashfs/xattr_id.c (limited to 'fs/squashfs/xattr_id.c') diff --git a/fs/squashfs/xattr_id.c b/fs/squashfs/xattr_id.c new file mode 100644 index 000000000000..a74101244a98 --- /dev/null +++ b/fs/squashfs/xattr_id.c @@ -0,0 +1,100 @@ +/* + * Squashfs - a compressed read only filesystem for Linux + * + * Copyright (c) 2010 + * Phillip Lougher + * + * 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 +#include +#include + +#include "squashfs_fs.h" +#include "squashfs_fs_sb.h" +#include "squashfs_fs_i.h" +#include "squashfs.h" + +/* + * Map xattr id using the xattr id look up table + */ +int squashfs_xattr_lookup(struct super_block *sb, unsigned int index, + int *count, int *size, 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; + __le64 *xid_table; + struct squashfs_xattr_id_table id_table; + int err; + + err = squashfs_read_table(sb, &id_table, start, sizeof(id_table)); + if (err < 0) { + ERROR("unable to read xattr id table\n"); + return ERR_PTR(err); + } + *xattr_table_start = le64_to_cpu(id_table.xattr_table_start); + *xattr_ids = le32_to_cpu(id_table.xattr_ids); + len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids); + + TRACE("In read_xattr_index_table, length %d\n", len); + + /* Allocate xattr id lookup table indexes */ + xid_table = kmalloc(len, GFP_KERNEL); + if (xid_table == NULL) { + ERROR("Failed to allocate xattr id index table\n"); + return ERR_PTR(-ENOMEM); + } + + err = squashfs_read_table(sb, xid_table, start + sizeof(id_table), len); + if (err < 0) { + ERROR("unable to read xattr id index table\n"); + kfree(xid_table); + return ERR_PTR(err); + } + + return xid_table; +} -- cgit v1.2.3-59-g8ed1b