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| author | Daeho Jeong <daehojeong@google.com> | 2020-12-01 05:08:02 +0100 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2020-12-03 09:11:57 +0100 |
| commit | 602a16d58e9aab3c423bcf051033ea6c9e8a6d37 (patch) | |
| tree | b14640b883fad02423a7ffe06f90607f585a0524 /Documentation/filesystems | |
| parent | f2fs: Remove unnecessary unlikely() (diff) | |
| download | linux-602a16d58e9aab3c423bcf051033ea6c9e8a6d37.tar.xz linux-602a16d58e9aab3c423bcf051033ea6c9e8a6d37.zip | |
f2fs: add compress_mode mount option
We will add a new "compress_mode" mount option to control file
compression mode. This supports "fs" and "user". In "fs" mode (default),
f2fs does automatic compression on the compression enabled files.
In "user" mode, f2fs disables the automaic compression and gives the
user discretion of choosing the target file and the timing. It means
the user can do manual compression/decompression on the compression
enabled files using ioctls.
Signed-off-by: Daeho Jeong <daehojeong@google.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/f2fs.rst | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst index 985ae7d35066..dae15c96e659 100644 --- a/Documentation/filesystems/f2fs.rst +++ b/Documentation/filesystems/f2fs.rst @@ -261,6 +261,13 @@ compress_extension=%s Support adding specified extension, so that f2fs can enab Note that, there is one reserved special extension '*', it can be set to enable compression for all files. compress_chksum Support verifying chksum of raw data in compressed cluster. +compress_mode=%s Control file compression mode. This supports "fs" and "user" + modes. In "fs" mode (default), f2fs does automatic compression + on the compression enabled files. In "user" mode, f2fs disables + the automaic compression and gives the user discretion of + choosing the target file and the timing. The user can do manual + compression/decompression on the compression enabled files using + ioctls. inlinecrypt When possible, encrypt/decrypt the contents of encrypted files using the blk-crypto framework rather than filesystem-layer encryption. This allows the use of @@ -811,6 +818,34 @@ Compress metadata layout:: | data length | data chksum | reserved | compressed data | +-------------+-------------+----------+----------------------------+ +Compression mode +-------------------------- + +f2fs supports "fs" and "user" compression modes with "compression_mode" mount option. +With this option, f2fs provides a choice to select the way how to compress the +compression enabled files (refer to "Compression implementation" section for how to +enable compression on a regular inode). + +1) compress_mode=fs +This is the default option. f2fs does automatic compression in the writeback of the +compression enabled files. + +2) compress_mode=user +This disables the automaic compression and gives the user discretion of choosing the +target file and the timing. The user can do manual compression/decompression on the +compression enabled files using F2FS_IOC_DECOMPRESS_FILE and F2FS_IOC_COMPRESS_FILE +ioctls like the below. + +To decompress a file, + +fd = open(filename, O_WRONLY, 0); +ret = ioctl(fd, F2FS_IOC_DECOMPRESS_FILE); + +To compress a file, + +fd = open(filename, O_WRONLY, 0); +ret = ioctl(fd, F2FS_IOC_COMPRESS_FILE); + NVMe Zoned Namespace devices ---------------------------- |