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Squashfs: Add LZ4 compression configuration option 

Add the glue code, and also update the documentation.

Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
This commit is contained in:
Phillip Lougher 2014-11-27 18:48:44 +00:00
parent 9c06a46f15
commit 62421645bb
5 changed files with 31 additions and 4 deletions
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8
Documentation/filesystems/squashfs.txt
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@ -2,10 +2,10 @@ SQUASHFS 4.0 FILESYSTEM
=======================
Squashfs is a compressed read-only filesystem for Linux.
It uses zlib/lzo/xz compression to compress 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 1Mbytes (default block size 128K).
It uses zlib, lz4, lzo, or xz compression to compress 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 1Mbytes (default block size 128K).
Squashfs is intended for general read-only filesystem use, for archival
use (i.e. in cases where a .tar.gz file may be used), and in constrained

15
fs/squashfs/Kconfig
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@ -120,6 +120,21 @@ config SQUASHFS_ZLIB
If unsure, say Y.
config SQUASHFS_LZ4
bool "Include support for LZ4 compressed file systems"
depends on SQUASHFS
select LZ4_DECOMPRESS
help
Saying Y here includes support for reading Squashfs file systems
compressed with LZ4 compression. LZ4 compression is mainly
aimed at embedded systems with slower CPUs where the overheads
of zlib are too high.
LZ4 is not the standard compression used in Squashfs and so most
file systems will be readable without selecting this option.
If unsure, say N.
config SQUASHFS_LZO
bool "Include support for LZO compressed file systems"
depends on SQUASHFS

1
fs/squashfs/Makefile
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@ -11,6 +11,7 @@ squashfs-$(CONFIG_SQUASHFS_DECOMP_SINGLE) += decompressor_single.o
squashfs-$(CONFIG_SQUASHFS_DECOMP_MULTI) += decompressor_multi.o
squashfs-$(CONFIG_SQUASHFS_DECOMP_MULTI_PERCPU) += decompressor_multi_percpu.o
squashfs-$(CONFIG_SQUASHFS_XATTR) += xattr.o xattr_id.o
squashfs-$(CONFIG_SQUASHFS_LZ4) += lz4_wrapper.o
squashfs-$(CONFIG_SQUASHFS_LZO) += lzo_wrapper.o
squashfs-$(CONFIG_SQUASHFS_XZ) += xz_wrapper.o
squashfs-$(CONFIG_SQUASHFS_ZLIB) += zlib_wrapper.o

7
fs/squashfs/decompressor.c
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@ -41,6 +41,12 @@ static const struct squashfs_decompressor squashfs_lzma_unsupported_comp_ops = {
NULL, NULL, NULL, NULL, LZMA_COMPRESSION, "lzma", 0
};
#ifndef CONFIG_SQUASHFS_LZ4
static const struct squashfs_decompressor squashfs_lz4_comp_ops = {
NULL, NULL, NULL, NULL, LZ4_COMPRESSION, "lz4", 0
};
#endif
#ifndef CONFIG_SQUASHFS_LZO
static const struct squashfs_decompressor squashfs_lzo_comp_ops = {
NULL, NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 0
@ -65,6 +71,7 @@ static const struct squashfs_decompressor squashfs_unknown_comp_ops = {
static const struct squashfs_decompressor *decompressor[] = {
&squashfs_zlib_comp_ops,
&squashfs_lz4_comp_ops,
&squashfs_lzo_comp_ops,
&squashfs_xz_comp_ops,
&squashfs_lzma_unsupported_comp_ops,

4
fs/squashfs/decompressor.h
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@ -46,6 +46,10 @@ static inline void *squashfs_comp_opts(struct squashfs_sb_info *msblk,
extern const struct squashfs_decompressor squashfs_xz_comp_ops;
#endif
#ifdef CONFIG_SQUASHFS_LZ4
extern const struct squashfs_decompressor squashfs_lz4_comp_ops;
#endif
#ifdef CONFIG_SQUASHFS_LZO
extern const struct squashfs_decompressor squashfs_lzo_comp_ops;
#endif