Commit Graph

6 Commits

Author SHA1 Message Date
Stefan Agner
59516f6017 Btrfs: return -1 when lzo compression makes data bigger
With this fix the lzo code behaves like the zlib code by returning an
error
code when compression does not help reduce the size of the file.
This is currently not a bug since the compressed size is checked again
in
the calling method compress_file_range.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-09-01 07:57:19 -04:00
Jie Liu
3fb4037599 btrfs: fix the code comments for LZO compression workspace
Fix the code comments for lzo compression workspace.
The buf item is used to store the decompressed data
and cbuf is used to store the compressed data.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-07-01 08:52:26 -04:00
Cong Wang
7ac687d9e0 btrfs: remove the second argument of k[un]map_atomic()
Signed-off-by: Cong Wang <amwang@redhat.com>
2012-03-20 21:48:21 +08:00
Li Zefan
ca9b688c1c Btrfs: Avoid accessing unmapped kernel address
When decompressing a chunk of data, we'll copy the data out to
a working buffer if the data is stored in more than one page,
otherwise we'll use the mapped page directly to avoid memory
copy.

In the latter case, we'll end up accessing the kernel address
after we've unmapped the page in a corner case.

Reported-by: Juan Francisco Cantero Hurtado <iam@juanfra.info>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-02-16 15:37:58 -05:00
Li Zefan
3a39c18d63 btrfs: Extract duplicate decompress code
Add a common function to copy decompressed data from working buffer
to bio pages.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
2010-12-22 23:15:50 +08:00
Li Zefan
a6fa6fae40 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: Li Zefan <lizf@cn.fujitsu.com>
2010-12-22 23:15:47 +08:00