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 <phillip@lougher.demon.co.uk>
This commit is contained in:
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b57f95a382
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4b5397dc24
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@ -5,3 +5,5 @@
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obj-$(CONFIG_SQUASHFS) += squashfs.o
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squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o
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squashfs-y += namei.o super.o symlink.o zlib_wrapper.o decompressor.o
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squashfs-y += xattr_id.o
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@ -73,6 +73,12 @@ extern struct inode *squashfs_iget(struct super_block *, long long,
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unsigned int);
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extern int squashfs_read_inode(struct inode *, long long);
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/* xattr_id.c */
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extern int squashfs_xattr_lookup(struct super_block *, unsigned int, int *,
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int *, long long *);
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extern __le64 *squashfs_read_xattr_id_table(struct super_block *, u64,
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u64 *, int *);
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/*
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* Inodes, files and decompressor operations
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*/
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@ -174,6 +174,24 @@
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#define SQUASHFS_ID_BLOCK_BYTES(A) (SQUASHFS_ID_BLOCKS(A) *\
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sizeof(u64))
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/* xattr id lookup table defines */
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#define SQUASHFS_XATTR_BYTES(A) ((A) * sizeof(struct squashfs_xattr_id))
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#define SQUASHFS_XATTR_BLOCK(A) (SQUASHFS_XATTR_BYTES(A) / \
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SQUASHFS_METADATA_SIZE)
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#define SQUASHFS_XATTR_BLOCK_OFFSET(A) (SQUASHFS_XATTR_BYTES(A) % \
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SQUASHFS_METADATA_SIZE)
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#define SQUASHFS_XATTR_BLOCKS(A) ((SQUASHFS_XATTR_BYTES(A) + \
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SQUASHFS_METADATA_SIZE - 1) / \
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SQUASHFS_METADATA_SIZE)
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#define SQUASHFS_XATTR_BLOCK_BYTES(A) (SQUASHFS_XATTR_BLOCKS(A) *\
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sizeof(u64))
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#define SQUASHFS_XATTR_BLK(A) ((unsigned int) ((A) >> 16))
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#define SQUASHFS_XATTR_OFFSET(A) ((unsigned int) ((A) & 0xffff))
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/* cached data constants for filesystem */
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#define SQUASHFS_CACHED_BLKS 8
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@ -228,7 +246,7 @@ struct squashfs_super_block {
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__le64 root_inode;
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__le64 bytes_used;
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__le64 id_table_start;
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__le64 xattr_table_start;
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__le64 xattr_id_table_start;
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__le64 inode_table_start;
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__le64 directory_table_start;
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__le64 fragment_table_start;
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@ -377,4 +395,16 @@ struct squashfs_fragment_entry {
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unsigned int unused;
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};
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struct squashfs_xattr_id {
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__le64 xattr;
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__le32 count;
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__le32 size;
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};
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struct squashfs_xattr_id_table {
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__le64 xattr_table_start;
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__le32 xattr_ids;
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__le32 unused;
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};
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#endif
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@ -61,6 +61,7 @@ struct squashfs_sb_info {
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int next_meta_index;
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__le64 *id_table;
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__le64 *fragment_index;
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__le64 *xattr_id_table;
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struct mutex read_data_mutex;
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struct mutex meta_index_mutex;
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struct meta_index *meta_index;
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@ -68,9 +69,11 @@ struct squashfs_sb_info {
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__le64 *inode_lookup_table;
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u64 inode_table;
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u64 directory_table;
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u64 xattr_table;
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unsigned int block_size;
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unsigned short block_log;
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long long bytes_used;
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unsigned int inodes;
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int xattr_ids;
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};
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#endif
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@ -36,6 +36,7 @@
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/magic.h>
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#include <linux/xattr.h>
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#include "squashfs_fs.h"
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#include "squashfs_fs_sb.h"
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@ -82,7 +83,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
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long long root_inode;
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unsigned short flags;
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unsigned int fragments;
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u64 lookup_table_start;
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u64 lookup_table_start, xattr_id_table_start;
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int err;
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TRACE("Entered squashfs_fill_superblock\n");
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@ -143,7 +144,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
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* Check if there's xattrs in the filesystem. These are not
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* supported in this version, so warn that they will be ignored.
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*/
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if (le64_to_cpu(sblk->xattr_table_start) != SQUASHFS_INVALID_BLK)
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if (le64_to_cpu(sblk->xattr_id_table_start) != SQUASHFS_INVALID_BLK)
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ERROR("Xattrs in filesystem, these will be ignored\n");
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/* Check the filesystem does not extend beyond the end of the
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@ -253,7 +254,7 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
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allocate_lookup_table:
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lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
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if (lookup_table_start == SQUASHFS_INVALID_BLK)
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goto allocate_root;
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goto allocate_xattr_table;
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/* Allocate and read inode lookup table */
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msblk->inode_lookup_table = squashfs_read_inode_lookup_table(sb,
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@ -266,6 +267,19 @@ allocate_lookup_table:
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sb->s_export_op = &squashfs_export_ops;
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allocate_xattr_table:
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xattr_id_table_start = le64_to_cpu(sblk->xattr_id_table_start);
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if (xattr_id_table_start == SQUASHFS_INVALID_BLK)
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goto allocate_root;
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/* Allocate and read xattr id lookup table */
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msblk->xattr_id_table = squashfs_read_xattr_id_table(sb,
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xattr_id_table_start, &msblk->xattr_table, &msblk->xattr_ids);
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if (IS_ERR(msblk->xattr_id_table)) {
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err = PTR_ERR(msblk->xattr_id_table);
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msblk->xattr_id_table = NULL;
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goto failed_mount;
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}
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allocate_root:
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root = new_inode(sb);
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if (!root) {
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@ -301,6 +315,7 @@ failed_mount:
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kfree(msblk->inode_lookup_table);
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kfree(msblk->fragment_index);
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kfree(msblk->id_table);
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kfree(msblk->xattr_id_table);
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kfree(sb->s_fs_info);
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sb->s_fs_info = NULL;
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kfree(sblk);
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@ -355,6 +370,7 @@ static void squashfs_put_super(struct super_block *sb)
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kfree(sbi->fragment_index);
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kfree(sbi->meta_index);
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kfree(sbi->inode_lookup_table);
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kfree(sbi->xattr_id_table);
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kfree(sb->s_fs_info);
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sb->s_fs_info = NULL;
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}
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@ -0,0 +1,100 @@
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/*
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* Squashfs - a compressed read only filesystem for Linux
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*
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* Copyright (c) 2010
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* Phillip Lougher <phillip@lougher.demon.co.uk>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2,
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* or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* xattr_id.c
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*/
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/*
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* This file implements code to map the 32-bit xattr id stored in the inode
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* into the on disk location of the xattr data.
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*/
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#include <linux/fs.h>
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#include <linux/vfs.h>
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#include <linux/slab.h>
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#include "squashfs_fs.h"
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#include "squashfs_fs_sb.h"
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#include "squashfs_fs_i.h"
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#include "squashfs.h"
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/*
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* Map xattr id using the xattr id look up table
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*/
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int squashfs_xattr_lookup(struct super_block *sb, unsigned int index,
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int *count, int *size, long long *xattr)
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{
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struct squashfs_sb_info *msblk = sb->s_fs_info;
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int block = SQUASHFS_XATTR_BLOCK(index);
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int offset = SQUASHFS_XATTR_BLOCK_OFFSET(index);
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u64 start_block = le64_to_cpu(msblk->xattr_id_table[block]);
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struct squashfs_xattr_id id;
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int err;
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err = squashfs_read_metadata(sb, &id, &start_block, &offset,
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sizeof(id));
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if (err < 0)
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return err;
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*xattr = le64_to_cpu(id.xattr);
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*size = le32_to_cpu(id.size);
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*count = le32_to_cpu(id.count);
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return 0;
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}
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/*
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* Read uncompressed xattr id lookup table indexes from disk into memory
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*/
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__le64 *squashfs_read_xattr_id_table(struct super_block *sb, u64 start,
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u64 *xattr_table_start, int *xattr_ids)
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{
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unsigned int len;
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__le64 *xid_table;
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struct squashfs_xattr_id_table id_table;
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int err;
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err = squashfs_read_table(sb, &id_table, start, sizeof(id_table));
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if (err < 0) {
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ERROR("unable to read xattr id table\n");
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return ERR_PTR(err);
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}
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*xattr_table_start = le64_to_cpu(id_table.xattr_table_start);
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*xattr_ids = le32_to_cpu(id_table.xattr_ids);
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len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids);
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TRACE("In read_xattr_index_table, length %d\n", len);
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/* Allocate xattr id lookup table indexes */
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xid_table = kmalloc(len, GFP_KERNEL);
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if (xid_table == NULL) {
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ERROR("Failed to allocate xattr id index table\n");
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return ERR_PTR(-ENOMEM);
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}
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err = squashfs_read_table(sb, xid_table, start + sizeof(id_table), len);
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if (err < 0) {
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ERROR("unable to read xattr id index table\n");
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kfree(xid_table);
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return ERR_PTR(err);
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}
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return xid_table;
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}
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