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Squashfs: add a decompressor framework

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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:
Phillip Lougher 2009-10-06 04:04:15 +01:00
parent f1a40359f8
commit 4c0f0bb235
8 changed files with 184 additions and 51 deletions
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2
fs/squashfs/Makefile
View File

@ -4,4 +4,4 @@
obj-$(CONFIG_SQUASHFS) += squashfs.o
squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o
squashfs-y += namei.o super.o symlink.o zlib_wrapper.o
squashfs-y += namei.o super.o symlink.o zlib_wrapper.o decompressor.o

3
fs/squashfs/block.c
View File

@ -36,6 +36,7 @@
#include "squashfs_fs_sb.h"
#include "squashfs_fs_i.h"
#include "squashfs.h"
#include "decompressor.h"
/*
* Read the metadata block length, this is stored in the first two
@ -151,7 +152,7 @@ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
}
if (compressed) {
length = squashfs_zlib_uncompress(msblk, buffer, bh, b, offset,
length = squashfs_decompress(msblk, buffer, bh, b, offset,
length, srclength, pages);
if (length < 0)
goto read_failure;

58
fs/squashfs/decompressor.c Normal file
View File

@ -0,0 +1,58 @@
/*
* Squashfs - a compressed read only filesystem for Linux
*
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
* Phillip Lougher <phillip@lougher.demon.co.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.
*
* decompressor.c
*/
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/buffer_head.h>
#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "squashfs_fs_i.h"
#include "decompressor.h"
#include "squashfs.h"
/*
* This file (and decompressor.h) implements a decompressor framework for
* Squashfs, allowing multiple decompressors to be easily supported
*/
static const struct squashfs_decompressor squashfs_unknown_comp_ops = {
NULL, NULL, NULL, 0, "unknown", 0
};
static const struct squashfs_decompressor *decompressor[] = {
&squashfs_zlib_comp_ops,
&squashfs_unknown_comp_ops
};
const struct squashfs_decompressor *squashfs_lookup_decompressor(int id)
{
int i;
for (i = 0; decompressor[i]->id; i++)
if (id == decompressor[i]->id)
break;
return decompressor[i];
}

55
fs/squashfs/decompressor.h Normal file
View File

@ -0,0 +1,55 @@
#ifndef DECOMPRESSOR_H
#define DECOMPRESSOR_H
/*
* Squashfs - a compressed read only filesystem for Linux
*
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
* Phillip Lougher <phillip@lougher.demon.co.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.
*
* decompressor.h
*/
struct squashfs_decompressor {
void *(*init)(struct squashfs_sb_info *);
void (*free)(void *);
int (*decompress)(struct squashfs_sb_info *, void **,
struct buffer_head **, int, int, int, int, int);
int id;
char *name;
int supported;
};
static inline void *squashfs_decompressor_init(struct squashfs_sb_info *msblk)
{
return msblk->decompressor->init(msblk);
}
static inline void squashfs_decompressor_free(struct squashfs_sb_info *msblk,
void *s)
{
if (msblk->decompressor)
msblk->decompressor->free(s);
}
static inline int squashfs_decompress(struct squashfs_sb_info *msblk,
void **buffer, struct buffer_head **bh, int b, int offset, int length,
int srclength, int pages)
{
return msblk->decompressor->decompress(msblk, buffer, bh, b, offset,
length, srclength, pages);
}
#endif

14
fs/squashfs/squashfs.h
View File

@ -51,6 +51,9 @@ extern struct squashfs_cache_entry *squashfs_get_datablock(struct super_block *,
u64, int);
extern int squashfs_read_table(struct super_block *, void *, u64, int);
/* decompressor.c */
extern const struct squashfs_decompressor *squashfs_lookup_decompressor(int);
/* export.c */
extern __le64 *squashfs_read_inode_lookup_table(struct super_block *, u64,
unsigned int);
@ -70,14 +73,8 @@ extern struct inode *squashfs_iget(struct super_block *, long long,
unsigned int);
extern int squashfs_read_inode(struct inode *, long long);
/* zlib_wrapper.c */
extern void *squashfs_zlib_init(void);
extern void squashfs_zlib_free(void *);
extern int squashfs_zlib_uncompress(struct squashfs_sb_info *, void **,
struct buffer_head **, int, int, int, int, int);
/*
* Inodes and files operations
* Inodes, files and decompressor operations
*/
/* dir.c */
@ -94,3 +91,6 @@ extern const struct inode_operations squashfs_dir_inode_ops;
/* symlink.c */
extern const struct address_space_operations squashfs_symlink_aops;
/* zlib_wrapper.c */
extern const struct squashfs_decompressor squashfs_zlib_comp_ops;

41
fs/squashfs/squashfs_fs_sb.h
View File

@ -52,25 +52,26 @@ struct squashfs_cache_entry {
};
struct squashfs_sb_info {
int devblksize;
int devblksize_log2;
struct squashfs_cache *block_cache;
struct squashfs_cache *fragment_cache;
struct squashfs_cache *read_page;
int next_meta_index;
__le64 *id_table;
__le64 *fragment_index;
unsigned int *fragment_index_2;
struct mutex read_data_mutex;
struct mutex meta_index_mutex;
struct meta_index *meta_index;
void *stream;
__le64 *inode_lookup_table;
u64 inode_table;
u64 directory_table;
unsigned int block_size;
unsigned short block_log;
long long bytes_used;
unsigned int inodes;
const struct squashfs_decompressor *decompressor;
int devblksize;
int devblksize_log2;
struct squashfs_cache *block_cache;
struct squashfs_cache *fragment_cache;
struct squashfs_cache *read_page;
int next_meta_index;
__le64 *id_table;
__le64 *fragment_index;
unsigned int *fragment_index_2;
struct mutex read_data_mutex;
struct mutex meta_index_mutex;
struct meta_index *meta_index;
void *stream;
__le64 *inode_lookup_table;
u64 inode_table;
u64 directory_table;
unsigned int block_size;
unsigned short block_log;
long long bytes_used;
unsigned int inodes;
};
#endif

45
fs/squashfs/super.c
View File

@ -41,27 +41,35 @@
#include "squashfs_fs_sb.h"
#include "squashfs_fs_i.h"
#include "squashfs.h"
#include "decompressor.h"
static struct file_system_type squashfs_fs_type;
static const struct super_operations squashfs_super_ops;
static int supported_squashfs_filesystem(short major, short minor, short comp)
static const struct squashfs_decompressor *supported_squashfs_filesystem(short
major, short minor, short id)
{
const struct squashfs_decompressor *decompressor;
if (major < SQUASHFS_MAJOR) {
ERROR("Major/Minor mismatch, older Squashfs %d.%d "
"filesystems are unsupported\n", major, minor);
return -EINVAL;
return NULL;
} else if (major > SQUASHFS_MAJOR || minor > SQUASHFS_MINOR) {
ERROR("Major/Minor mismatch, trying to mount newer "
"%d.%d filesystem\n", major, minor);
ERROR("Please update your kernel\n");
return -EINVAL;
return NULL;
}
if (comp != ZLIB_COMPRESSION)
return -EINVAL;
decompressor = squashfs_lookup_decompressor(id);
if (!decompressor->supported) {
ERROR("Filesystem uses \"%s\" compression. This is not "
"supported\n", decompressor->name);
return NULL;
}
return 0;
return decompressor;
}
@ -86,10 +94,6 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
}
msblk = sb->s_fs_info;
msblk->stream = squashfs_zlib_init();
if (msblk->stream == NULL)
goto failure;
sblk = kzalloc(sizeof(*sblk), GFP_KERNEL);
if (sblk == NULL) {
ERROR("Failed to allocate squashfs_super_block\n");
@ -116,25 +120,25 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
goto failed_mount;
}
err = -EINVAL;
/* Check it is a SQUASHFS superblock */
sb->s_magic = le32_to_cpu(sblk->s_magic);
if (sb->s_magic != SQUASHFS_MAGIC) {
if (!silent)
ERROR("Can't find a SQUASHFS superblock on %s\n",
bdevname(sb->s_bdev, b));
err = -EINVAL;
goto failed_mount;
}
/* Check the MAJOR & MINOR versions and compression type */
err = supported_squashfs_filesystem(le16_to_cpu(sblk->s_major),
/* Check the MAJOR & MINOR versions and lookup compression type */
msblk->decompressor = supported_squashfs_filesystem(
le16_to_cpu(sblk->s_major),
le16_to_cpu(sblk->s_minor),
le16_to_cpu(sblk->compression));
if (err < 0)
if (msblk->decompressor == NULL)
goto failed_mount;
err = -EINVAL;
/*
* Check if there's xattrs in the filesystem. These are not
* supported in this version, so warn that they will be ignored.
@ -201,6 +205,10 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
err = -ENOMEM;
msblk->stream = squashfs_decompressor_init(msblk);
if (msblk->stream == NULL)
goto failed_mount;
msblk->block_cache = squashfs_cache_init("metadata",
SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
if (msblk->block_cache == NULL)
@ -288,7 +296,7 @@ failed_mount:
squashfs_cache_delete(msblk->block_cache);
squashfs_cache_delete(msblk->fragment_cache);
squashfs_cache_delete(msblk->read_page);
squashfs_zlib_free(msblk->stream);
squashfs_decompressor_free(msblk, msblk->stream);
kfree(msblk->inode_lookup_table);
kfree(msblk->fragment_index);
kfree(msblk->id_table);
@ -298,7 +306,6 @@ failed_mount:
return err;
failure:
squashfs_zlib_free(msblk->stream);
kfree(sb->s_fs_info);
sb->s_fs_info = NULL;
return -ENOMEM;
@ -342,7 +349,7 @@ static void squashfs_put_super(struct super_block *sb)
squashfs_cache_delete(sbi->block_cache);
squashfs_cache_delete(sbi->fragment_cache);
squashfs_cache_delete(sbi->read_page);
squashfs_zlib_free(sbi->stream);
squashfs_decompressor_free(sbi, sbi->stream);
kfree(sbi->id_table);
kfree(sbi->fragment_index);
kfree(sbi->meta_index);

17
fs/squashfs/zlib_wrapper.c
View File

@ -30,8 +30,9 @@
#include "squashfs_fs_sb.h"
#include "squashfs_fs_i.h"
#include "squashfs.h"
#include "decompressor.h"
void *squashfs_zlib_init()
static void *zlib_init(struct squashfs_sb_info *dummy)
{
z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL);
if (stream == NULL)
@ -50,7 +51,7 @@ failed:
}
void squashfs_zlib_free(void *strm)
static void zlib_free(void *strm)
{
z_stream *stream = strm;
@ -60,7 +61,7 @@ void squashfs_zlib_free(void *strm)
}
int squashfs_zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer,
static int zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer,
struct buffer_head **bh, int b, int offset, int length, int srclength,
int pages)
{
@ -137,3 +138,13 @@ release_mutex:
return -EIO;
}
const struct squashfs_decompressor squashfs_zlib_comp_ops = {
.init = zlib_init,
.free = zlib_free,
.decompress = zlib_uncompress,
.id = ZLIB_COMPRESSION,
.name = "zlib",
.supported = 1
};