Commit 38740707 authored by Chao Yu's avatar Chao Yu Committed by Jaegeuk Kim
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f2fs: document: add description about compressed space handling 



User or developer may still be confused about why f2fs doesn't expose
compressed space to userspace, add description about compressed space
handling policy into f2fs documentation.

Signed-off-by: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 5f029c04

Documentation/filesystems/f2fs.rst

+8 −0
Original line number Diff line number Diff line
@@ -819,6 +819,14 @@ Compression implementation 
  * chattr +c file

  * chattr +c dir; touch dir/file

  * mount w/ -o compress_extension=ext; touch file.ext

  * mount w/ -o compress_extension=*; touch any_file



- At this point, compression feature doesn't expose compressed space to user

  directly in order to guarantee potential data updates later to the space.

  Instead, the main goal is to reduce data writes to flash disk as much as

  possible, resulting in extending disk life time as well as relaxing IO

  congestion. Alternatively, we've added ioctl interface to reclaim compressed

  space and show it to user after putting the immutable bit.



Compress metadata layout::