Squashfs: add a decompressor framework
This adds a decompressor framework which allows multiple compression algorithms to be cleanly supported. Also update zlib wrapper and other code to use the new framework. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
This commit is contained in:
parent
f1a40359f8
commit
4c0f0bb235
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@ -4,4 +4,4 @@
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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
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squashfs-y += namei.o super.o symlink.o zlib_wrapper.o decompressor.o
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@ -36,6 +36,7 @@
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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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#include "decompressor.h"
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/*
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* Read the metadata block length, this is stored in the first two
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@ -151,7 +152,7 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
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}
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if (compressed) {
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length = squashfs_zlib_uncompress(msblk, buffer, bh, b, offset,
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length = squashfs_decompress(msblk, buffer, bh, b, offset,
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length, srclength, pages);
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if (length < 0)
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goto read_failure;
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@ -0,0 +1,58 @@
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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) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
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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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* decompressor.c
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*/
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#include <linux/types.h>
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#include <linux/mutex.h>
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#include <linux/buffer_head.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 "decompressor.h"
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#include "squashfs.h"
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/*
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* This file (and decompressor.h) implements a decompressor framework for
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* Squashfs, allowing multiple decompressors to be easily supported
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*/
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static const struct squashfs_decompressor squashfs_unknown_comp_ops = {
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NULL, NULL, NULL, 0, "unknown", 0
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};
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static const struct squashfs_decompressor *decompressor[] = {
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&squashfs_zlib_comp_ops,
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&squashfs_unknown_comp_ops
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};
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const struct squashfs_decompressor *squashfs_lookup_decompressor(int id)
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{
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int i;
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for (i = 0; decompressor[i]->id; i++)
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if (id == decompressor[i]->id)
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break;
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return decompressor[i];
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}
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@ -0,0 +1,55 @@
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#ifndef DECOMPRESSOR_H
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#define DECOMPRESSOR_H
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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) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
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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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* decompressor.h
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*/
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struct squashfs_decompressor {
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void *(*init)(struct squashfs_sb_info *);
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void (*free)(void *);
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int (*decompress)(struct squashfs_sb_info *, void **,
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struct buffer_head **, int, int, int, int, int);
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int id;
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char *name;
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int supported;
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};
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static inline void *squashfs_decompressor_init(struct squashfs_sb_info *msblk)
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{
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return msblk->decompressor->init(msblk);
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}
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static inline void squashfs_decompressor_free(struct squashfs_sb_info *msblk,
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void *s)
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{
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if (msblk->decompressor)
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msblk->decompressor->free(s);
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}
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static inline int squashfs_decompress(struct squashfs_sb_info *msblk,
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void **buffer, struct buffer_head **bh, int b, int offset, int length,
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int srclength, int pages)
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{
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return msblk->decompressor->decompress(msblk, buffer, bh, b, offset,
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length, srclength, pages);
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}
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#endif
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@ -51,6 +51,9 @@ extern struct squashfs_cache_entry *squashfs_get_datablock(struct super_block *,
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u64, int);
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extern int squashfs_read_table(struct super_block *, void *, u64, int);
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/* decompressor.c */
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extern const struct squashfs_decompressor *squashfs_lookup_decompressor(int);
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/* export.c */
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extern __le64 *squashfs_read_inode_lookup_table(struct super_block *, u64,
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unsigned int);
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@ -70,14 +73,8 @@ 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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/* zlib_wrapper.c */
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extern void *squashfs_zlib_init(void);
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extern void squashfs_zlib_free(void *);
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extern int squashfs_zlib_uncompress(struct squashfs_sb_info *, void **,
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struct buffer_head **, int, int, int, int, int);
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/*
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* Inodes and files operations
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* Inodes, files and decompressor operations
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*/
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/* dir.c */
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/* symlink.c */
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extern const struct address_space_operations squashfs_symlink_aops;
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/* zlib_wrapper.c */
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extern const struct squashfs_decompressor squashfs_zlib_comp_ops;
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@ -52,25 +52,26 @@ struct squashfs_cache_entry {
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};
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struct squashfs_sb_info {
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int devblksize;
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int devblksize_log2;
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struct squashfs_cache *block_cache;
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struct squashfs_cache *fragment_cache;
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struct squashfs_cache *read_page;
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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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unsigned int *fragment_index_2;
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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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void *stream;
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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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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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const struct squashfs_decompressor *decompressor;
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int devblksize;
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int devblksize_log2;
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struct squashfs_cache *block_cache;
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struct squashfs_cache *fragment_cache;
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struct squashfs_cache *read_page;
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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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unsigned int *fragment_index_2;
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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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void *stream;
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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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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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};
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#endif
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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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#include "decompressor.h"
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static struct file_system_type squashfs_fs_type;
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static const struct super_operations squashfs_super_ops;
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static int supported_squashfs_filesystem(short major, short minor, short comp)
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static const struct squashfs_decompressor *supported_squashfs_filesystem(short
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major, short minor, short id)
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{
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const struct squashfs_decompressor *decompressor;
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if (major < SQUASHFS_MAJOR) {
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ERROR("Major/Minor mismatch, older Squashfs %d.%d "
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"filesystems are unsupported\n", major, minor);
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return -EINVAL;
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return NULL;
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} else if (major > SQUASHFS_MAJOR || minor > SQUASHFS_MINOR) {
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ERROR("Major/Minor mismatch, trying to mount newer "
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"%d.%d filesystem\n", major, minor);
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ERROR("Please update your kernel\n");
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return -EINVAL;
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return NULL;
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}
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if (comp != ZLIB_COMPRESSION)
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return -EINVAL;
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decompressor = squashfs_lookup_decompressor(id);
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if (!decompressor->supported) {
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ERROR("Filesystem uses \"%s\" compression. This is not "
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"supported\n", decompressor->name);
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return NULL;
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}
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return 0;
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return decompressor;
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}
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}
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msblk = sb->s_fs_info;
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msblk->stream = squashfs_zlib_init();
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if (msblk->stream == NULL)
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goto failure;
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sblk = kzalloc(sizeof(*sblk), GFP_KERNEL);
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if (sblk == NULL) {
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ERROR("Failed to allocate squashfs_super_block\n");
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goto failed_mount;
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}
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err = -EINVAL;
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/* Check it is a SQUASHFS superblock */
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sb->s_magic = le32_to_cpu(sblk->s_magic);
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if (sb->s_magic != SQUASHFS_MAGIC) {
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if (!silent)
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ERROR("Can't find a SQUASHFS superblock on %s\n",
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bdevname(sb->s_bdev, b));
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err = -EINVAL;
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goto failed_mount;
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}
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/* Check the MAJOR & MINOR versions and compression type */
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err = supported_squashfs_filesystem(le16_to_cpu(sblk->s_major),
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/* Check the MAJOR & MINOR versions and lookup compression type */
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msblk->decompressor = supported_squashfs_filesystem(
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le16_to_cpu(sblk->s_major),
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le16_to_cpu(sblk->s_minor),
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le16_to_cpu(sblk->compression));
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if (err < 0)
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if (msblk->decompressor == NULL)
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goto failed_mount;
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err = -EINVAL;
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/*
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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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err = -ENOMEM;
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msblk->stream = squashfs_decompressor_init(msblk);
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if (msblk->stream == NULL)
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goto failed_mount;
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msblk->block_cache = squashfs_cache_init("metadata",
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SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
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if (msblk->block_cache == NULL)
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squashfs_cache_delete(msblk->block_cache);
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squashfs_cache_delete(msblk->fragment_cache);
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squashfs_cache_delete(msblk->read_page);
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squashfs_zlib_free(msblk->stream);
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squashfs_decompressor_free(msblk, msblk->stream);
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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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return err;
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failure:
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squashfs_zlib_free(msblk->stream);
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kfree(sb->s_fs_info);
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sb->s_fs_info = NULL;
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return -ENOMEM;
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squashfs_cache_delete(sbi->block_cache);
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squashfs_cache_delete(sbi->fragment_cache);
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squashfs_cache_delete(sbi->read_page);
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squashfs_zlib_free(sbi->stream);
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squashfs_decompressor_free(sbi, sbi->stream);
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kfree(sbi->id_table);
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kfree(sbi->fragment_index);
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kfree(sbi->meta_index);
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@ -30,8 +30,9 @@
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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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#include "decompressor.h"
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void *squashfs_zlib_init()
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static void *zlib_init(struct squashfs_sb_info *dummy)
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{
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z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL);
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if (stream == NULL)
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}
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void squashfs_zlib_free(void *strm)
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static void zlib_free(void *strm)
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{
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z_stream *stream = strm;
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}
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int squashfs_zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer,
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static int zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer,
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struct buffer_head **bh, int b, int offset, int length, int srclength,
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int pages)
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{
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return -EIO;
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}
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const struct squashfs_decompressor squashfs_zlib_comp_ops = {
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.init = zlib_init,
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.free = zlib_free,
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.decompress = zlib_uncompress,
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.id = ZLIB_COMPRESSION,
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.name = "zlib",
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.supported = 1
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};
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