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Merge git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-linus 

* git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-linus:
  Squashfs: Use vmalloc rather than kmalloc for zlib workspace
  Squashfs: handle corruption of directory structure
  Squashfs: wrap squashfs_mount() definition
  Squashfs: xz_wrapper doesn't need to include squashfs_fs_i.h anymore
  Squashfs: Update documentation to include compression options
  Squashfs: Update Kconfig help text to include xz compression
  Squashfs: add compression options support to xz decompressor
  Squashfs: extend decompressor framework to handle compression options
This commit is contained in:
Linus Torvalds 2011-03-24 08:02:21 -07:00
parent 0625bef606 117a91e0f2
commit 5818fcc8bd
12 changed files with 146 additions and 45 deletions
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28
Documentation/filesystems/squashfs.txt
View File

@ -59,12 +59,15 @@ obtained from this site also.
3. SQUASHFS FILESYSTEM DESIGN
-----------------------------
A squashfs filesystem consists of a maximum of eight parts, packed together on a byte
alignment:
A squashfs filesystem consists of a maximum of nine parts, packed together on a
byte alignment:
---------------
| superblock |
|---------------|
| compression |
| options |
|---------------|
| datablocks |
| & fragments |
|---------------|
@ -91,7 +94,14 @@ the source directory, and checked for duplicates. Once all file data has been
written the completed inode, directory, fragment, export and uid/gid lookup
tables are written.
3.1 Inodes
3.1 Compression options
-----------------------
Compressors can optionally support compression specific options (e.g.
dictionary size). If non-default compression options have been used, then
these are stored here.
3.2 Inodes
----------
Metadata (inodes and directories) are compressed in 8Kbyte blocks. Each
@ -114,7 +124,7 @@ directory inode are defined: inodes optimised for frequently occurring
regular files and directories, and extended types where extra
information has to be stored.
3.2 Directories
3.3 Directories
---------------
Like inodes, directories are packed into compressed metadata blocks, stored
@ -144,7 +154,7 @@ decompressed to do a lookup irrespective of the length of the directory.
This scheme has the advantage that it doesn't require extra memory overhead
and doesn't require much extra storage on disk.
3.3 File data
3.4 File data
-------------
Regular files consist of a sequence of contiguous compressed blocks, and/or a
@ -163,7 +173,7 @@ Larger files use multiple slots, with 1.75 TiB files using all 8 slots.
The index cache is designed to be memory efficient, and by default uses
16 KiB.
3.4 Fragment lookup table
3.5 Fragment lookup table
-------------------------
Regular files can contain a fragment index which is mapped to a fragment
@ -173,7 +183,7 @@ A second index table is used to locate these. This second index table for
speed of access (and because it is small) is read at mount time and cached
in memory.
3.5 Uid/gid lookup table
3.6 Uid/gid lookup table
------------------------
For space efficiency regular files store uid and gid indexes, which are
@ -182,7 +192,7 @@ stored compressed into metadata blocks. A second index table is used to
locate these. This second index table for speed of access (and because it
is small) is read at mount time and cached in memory.
3.6 Export table
3.7 Export table
----------------
To enable Squashfs filesystems to be exportable (via NFS etc.) filesystems
@ -196,7 +206,7 @@ This table is stored compressed into metadata blocks. A second index table is
used to locate these. This second index table for speed of access (and because
it is small) is read at mount time and cached in memory.
3.7 Xattr table
3.8 Xattr table
---------------
The xattr table contains extended attributes for each inode. The xattrs

12
fs/squashfs/Kconfig
View File

@ -5,12 +5,12 @@ config SQUASHFS
help
Saying Y here includes support for SquashFS 4.0 (a Compressed
Read-Only File System). Squashfs is a highly compressed read-only
filesystem for Linux. It uses zlib/lzo compression to compress both
files, inodes and directories. Inodes in the system are very small
and all blocks are packed to minimise data overhead. Block sizes
greater than 4K are supported up to a maximum of 1 Mbytes (default
block size 128K). SquashFS 4.0 supports 64 bit filesystems and files
(larger than 4GB), full uid/gid information, hard links and
filesystem for Linux. It uses zlib, lzo or xz compression to
compress both files, inodes and directories. Inodes in the system
are very small and all blocks are packed to minimise data overhead.
Block sizes greater than 4K are supported up to a maximum of 1 Mbytes
(default block size 128K). SquashFS 4.0 supports 64 bit filesystems
and files (larger than 4GB), full uid/gid information, hard links and
timestamps.
Squashfs is intended for general read-only filesystem use, for

34
fs/squashfs/decompressor.c
View File

@ -23,6 +23,7 @@
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/buffer_head.h>
#include "squashfs_fs.h"
@ -74,3 +75,36 @@ const struct squashfs_decompressor *squashfs_lookup_decompressor(int id)
return decompressor[i];
}
void *squashfs_decompressor_init(struct super_block *sb, unsigned short flags)
{
struct squashfs_sb_info *msblk = sb->s_fs_info;
void *strm, *buffer = NULL;
int length = 0;
/*
* Read decompressor specific options from file system if present
*/
if (SQUASHFS_COMP_OPTS(flags)) {
buffer = kmalloc(PAGE_CACHE_SIZE, GFP_KERNEL);
if (buffer == NULL)
return ERR_PTR(-ENOMEM);
length = squashfs_read_data(sb, &buffer,
sizeof(struct squashfs_super_block), 0, NULL,
PAGE_CACHE_SIZE, 1);
if (length < 0) {
strm = ERR_PTR(length);
goto finished;
}
}
strm = msblk->decompressor->init(msblk, buffer, length);
finished:
kfree(buffer);
return strm;
}

7
fs/squashfs/decompressor.h
View File

@ -24,7 +24,7 @@
*/
struct squashfs_decompressor {
void *(*init)(struct squashfs_sb_info *);
void *(*init)(struct squashfs_sb_info *, void *, int);
void (*free)(void *);
int (*decompress)(struct squashfs_sb_info *, void **,
struct buffer_head **, int, int, int, int, int);
@ -33,11 +33,6 @@ struct squashfs_decompressor {
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)
{

9
fs/squashfs/dir.c
View File

@ -172,6 +172,11 @@ static int squashfs_readdir(struct file *file, void *dirent, filldir_t filldir)
length += sizeof(dirh);
dir_count = le32_to_cpu(dirh.count) + 1;
/* dir_count should never be larger than 256 */
if (dir_count > 256)
goto failed_read;
while (dir_count--) {
/*
* Read directory entry.
@ -183,6 +188,10 @@ static int squashfs_readdir(struct file *file, void *dirent, filldir_t filldir)
size = le16_to_cpu(dire->size) + 1;
/* size should never be larger than SQUASHFS_NAME_LEN */
if (size > SQUASHFS_NAME_LEN)
goto failed_read;
err = squashfs_read_metadata(inode->i_sb, dire->name,
&block, &offset, size);
if (err < 0)

4
fs/squashfs/lzo_wrapper.c
View File

@ -37,7 +37,7 @@ struct squashfs_lzo {
void *output;
};
static void *lzo_init(struct squashfs_sb_info *msblk)
static void *lzo_init(struct squashfs_sb_info *msblk, void *buff, int len)
{
int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);
@ -58,7 +58,7 @@ failed2:
failed:
ERROR("Failed to allocate lzo workspace\n");
kfree(stream);
return NULL;
return ERR_PTR(-ENOMEM);
}

12
fs/squashfs/namei.c
View File

@ -176,6 +176,11 @@ static struct dentry *squashfs_lookup(struct inode *dir, struct dentry *dentry,
length += sizeof(dirh);
dir_count = le32_to_cpu(dirh.count) + 1;
/* dir_count should never be larger than 256 */
if (dir_count > 256)
goto data_error;
while (dir_count--) {
/*
* Read directory entry.
@ -187,6 +192,10 @@ static struct dentry *squashfs_lookup(struct inode *dir, struct dentry *dentry,
size = le16_to_cpu(dire->size) + 1;
/* size should never be larger than SQUASHFS_NAME_LEN */
if (size > SQUASHFS_NAME_LEN)
goto data_error;
err = squashfs_read_metadata(dir->i_sb, dire->name,
&block, &offset, size);
if (err < 0)
@ -228,6 +237,9 @@ exit_lookup:
d_add(dentry, inode);
return ERR_PTR(0);
data_error:
err = -EIO;
read_failure:
ERROR("Unable to read directory block [%llx:%x]\n",
squashfs_i(dir)->start + msblk->directory_table,

1
fs/squashfs/squashfs.h
View File

@ -48,6 +48,7 @@ extern int squashfs_read_table(struct super_block *, void *, u64, int);
/* decompressor.c */
extern const struct squashfs_decompressor *squashfs_lookup_decompressor(int);
extern void *squashfs_decompressor_init(struct super_block *, unsigned short);
/* export.c */
extern __le64 *squashfs_read_inode_lookup_table(struct super_block *, u64,

4
fs/squashfs/squashfs_fs.h
View File

@ -57,6 +57,7 @@
#define SQUASHFS_ALWAYS_FRAG 5
#define SQUASHFS_DUPLICATE 6
#define SQUASHFS_EXPORT 7
#define SQUASHFS_COMP_OPT 10
#define SQUASHFS_BIT(flag, bit) ((flag >> bit) & 1)
@ -81,6 +82,9 @@
#define SQUASHFS_EXPORTABLE(flags) SQUASHFS_BIT(flags, \
SQUASHFS_EXPORT)
#define SQUASHFS_COMP_OPTS(flags) SQUASHFS_BIT(flags, \
SQUASHFS_COMP_OPT)
/* Max number of types and file types */
#define SQUASHFS_DIR_TYPE 1
#define SQUASHFS_REG_TYPE 2

15
fs/squashfs/super.c
View File

@ -199,10 +199,6 @@ 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)
@ -215,6 +211,13 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
goto failed_mount;
}
msblk->stream = squashfs_decompressor_init(sb, flags);
if (IS_ERR(msblk->stream)) {
err = PTR_ERR(msblk->stream);
msblk->stream = NULL;
goto failed_mount;
}
/* Allocate and read id index table */
msblk->id_table = squashfs_read_id_index_table(sb,
le64_to_cpu(sblk->id_table_start), le16_to_cpu(sblk->no_ids));
@ -370,8 +373,8 @@ static void squashfs_put_super(struct super_block *sb)
}
static struct dentry *squashfs_mount(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data)
static struct dentry *squashfs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
return mount_bdev(fs_type, flags, dev_name, data, squashfs_fill_super);
}

55
fs/squashfs/xz_wrapper.c
View File

@ -26,10 +26,10 @@
#include <linux/buffer_head.h>
#include <linux/slab.h>
#include <linux/xz.h>
#include <linux/bitops.h>
#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "squashfs_fs_i.h"
#include "squashfs.h"
#include "decompressor.h"
@ -38,24 +38,57 @@ struct squashfs_xz {
struct xz_buf buf;
};
static void *squashfs_xz_init(struct squashfs_sb_info *msblk)
struct comp_opts {
__le32 dictionary_size;
__le32 flags;
};
static void *squashfs_xz_init(struct squashfs_sb_info *msblk, void *buff,
int len)
{
int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);
struct comp_opts *comp_opts = buff;
struct squashfs_xz *stream;
int dict_size = msblk->block_size;
int err, n;
struct squashfs_xz *stream = kmalloc(sizeof(*stream), GFP_KERNEL);
if (stream == NULL)
goto failed;
if (comp_opts) {
/* check compressor options are the expected length */
if (len < sizeof(*comp_opts)) {
err = -EIO;
goto failed;
}
stream->state = xz_dec_init(XZ_PREALLOC, block_size);
if (stream->state == NULL)
dict_size = le32_to_cpu(comp_opts->dictionary_size);
/* the dictionary size should be 2^n or 2^n+2^(n+1) */
n = ffs(dict_size) - 1;
if (dict_size != (1 << n) && dict_size != (1 << n) +
(1 << (n + 1))) {
err = -EIO;
goto failed;
}
}
dict_size = max_t(int, dict_size, SQUASHFS_METADATA_SIZE);
stream = kmalloc(sizeof(*stream), GFP_KERNEL);
if (stream == NULL) {
err = -ENOMEM;
goto failed;
}
stream->state = xz_dec_init(XZ_PREALLOC, dict_size);
if (stream->state == NULL) {
kfree(stream);
err = -ENOMEM;
goto failed;
}
return stream;
failed:
ERROR("Failed to allocate xz workspace\n");
kfree(stream);
return NULL;
ERROR("Failed to initialise xz decompressor\n");
return ERR_PTR(err);
}

10
fs/squashfs/zlib_wrapper.c
View File

@ -26,19 +26,19 @@
#include <linux/buffer_head.h>
#include <linux/slab.h>
#include <linux/zlib.h>
#include <linux/vmalloc.h>
#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "squashfs.h"
#include "decompressor.h"
static void *zlib_init(struct squashfs_sb_info *dummy)
static void *zlib_init(struct squashfs_sb_info *dummy, void *buff, int len)
{
z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL);
if (stream == NULL)
goto failed;
stream->workspace = kmalloc(zlib_inflate_workspacesize(),
GFP_KERNEL);
stream->workspace = vmalloc(zlib_inflate_workspacesize());
if (stream->workspace == NULL)
goto failed;
@ -47,7 +47,7 @@ static void *zlib_init(struct squashfs_sb_info *dummy)
failed:
ERROR("Failed to allocate zlib workspace\n");
kfree(stream);
return NULL;
return ERR_PTR(-ENOMEM);
}
@ -56,7 +56,7 @@ static void zlib_free(void *strm)
z_stream *stream = strm;
if (stream)
kfree(stream->workspace);
vfree(stream->workspace);
kfree(stream);
}