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Commit a6fa6fae authored by Li Zefan's avatar Li Zefan
Browse files

btrfs: Add lzo compression support 



Lzo is a much faster compression algorithm than gzib, so would allow
more users to enable transparent compression, and some users can
choose from compression ratio and speed for different applications

Usage:

 # mount -t btrfs -o compress[=<zlib,lzo>] dev /mnt
or
 # mount -t btrfs -o compress-force[=<zlib,lzo>] dev /mnt

"-o compress" without argument is still allowed for compatability.

Compatibility:

If we mount a filesystem with lzo compression, it will not be able be
mounted in old kernels. One reason is, otherwise btrfs will directly
dump compressed data, which sits in inline extent, to user.

Performance:

The test copied a linux source tarball (~400M) from an ext4 partition
to the btrfs partition, and then extracted it.

(time in second)
           lzo        zlib        nocompress
copy:      10.6       21.7        14.9
extract:   70.1       94.4        66.6

(data size in MB)
           lzo        zlib        nocompress
copy:      185.87     108.69      394.49
extract:   193.80     132.36      381.21

Changelog:

v1 -> v2:
- Select LZO_COMPRESS and LZO_DECOMPRESS in btrfs Kconfig.
- Add incompability flag.
- Fix error handling in compress code.

Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
parent 261507a0

fs/btrfs/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -4,6 +4,8 @@ config BTRFS_FS 
	select LIBCRC32C

	select ZLIB_INFLATE

	select ZLIB_DEFLATE

	select LZO_COMPRESS

	select LZO_DECOMPRESS

	help

	  Btrfs is a new filesystem with extents, writable snapshotting,

	  support for multiple devices and many more features.

fs/btrfs/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -6,5 +6,5 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \ 
	   transaction.o inode.o file.o tree-defrag.o \

	   extent_map.o sysfs.o struct-funcs.o xattr.o ordered-data.o \

	   extent_io.o volumes.o async-thread.o ioctl.o locking.o orphan.o \

	   export.o tree-log.o acl.o free-space-cache.o zlib.o \

	   export.o tree-log.o acl.o free-space-cache.o zlib.o lzo.o \

	   compression.o delayed-ref.o relocation.o

fs/btrfs/compression.c

+1 −0
Original line number Diff line number Diff line
@@ -691,6 +691,7 @@ static wait_queue_head_t comp_workspace_wait[BTRFS_COMPRESS_TYPES]; 


struct btrfs_compress_op *btrfs_compress_op[] = {

	&btrfs_zlib_compress,

	&btrfs_lzo_compress,

};



int __init btrfs_init_compress(void)

fs/btrfs/compression.h

+1 −0
Original line number Diff line number Diff line
@@ -73,5 +73,6 @@ struct btrfs_compress_op { 
};



extern struct btrfs_compress_op btrfs_zlib_compress;

extern struct btrfs_compress_op btrfs_lzo_compress;



#endif

fs/btrfs/ctree.h

+6 −3
Original line number Diff line number Diff line
@@ -398,13 +398,15 @@ struct btrfs_super_block { 
#define BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF	(1ULL << 0)

#define BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL	(1ULL << 1)

#define BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS	(1ULL << 2)

#define BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO	(1ULL << 3)



#define BTRFS_FEATURE_COMPAT_SUPP		0ULL

#define BTRFS_FEATURE_COMPAT_RO_SUPP		0ULL

#define BTRFS_FEATURE_INCOMPAT_SUPP			\

	(BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF |		\

	 BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL |	\

	 BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)

	 BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS |		\

	 BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO)



/*

 * A leaf is full of items. offset and size tell us where to find
@@ -553,8 +555,9 @@ struct btrfs_timespec { 
enum btrfs_compression_type {

	BTRFS_COMPRESS_NONE  = 0,

	BTRFS_COMPRESS_ZLIB  = 1,

	BTRFS_COMPRESS_TYPES = 1,

	BTRFS_COMPRESS_LAST  = 2,

	BTRFS_COMPRESS_LZO   = 2,

	BTRFS_COMPRESS_TYPES = 2,

	BTRFS_COMPRESS_LAST  = 3,

};



struct btrfs_inode_item {