path: root/Documentation/filesystems
diff options
authorChao Yu <>2021-04-13 17:56:53 +0800
committerJaegeuk Kim <>2021-04-13 10:40:59 -0700
commit38740707c5bc1253069eb932bc6d244f80ec21f0 (patch)
treee1f883aab08b93f9247eeaac3f7be37be23fa3d0 /Documentation/filesystems
parent5f029c045c948b6cb8ccfda614e73240c4a8363b (diff)
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: Chao Yu <> Signed-off-by: Jaegeuk Kim <>
Diffstat (limited to 'Documentation/filesystems')
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst
index 63c0c49b726d..992bf91eeec8 100644
--- a/Documentation/filesystems/f2fs.rst
+++ b/Documentation/filesystems/f2fs.rst
@@ -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::