Messages in this thread | | | Date | Fri, 10 Jun 2022 21:05:57 +0800 | Subject | Re: [PATCH] docs: filesystems: f2fs: fix description about compress ioctl | From | Chao Yu <> |
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On 2022/6/2 15:25, Chao Liu wrote: > From: Chao Liu <liuchao@coolpad.com> > > Since commit c61404153eb6 ("f2fs: introduce FI_COMPRESS_RELEASED > instead of using IMMUTABLE bit"), we no longer use the IMMUTABLE > bit to prevent writing data for compression. Let's correct the > corresponding documentation. > > BTW, this patch fixes some alignment issues in the compress > metadata layout. > > Signed-off-by: Chao Liu <liuchao@coolpad.com> > --- > Documentation/filesystems/f2fs.rst | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) > > diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst > index ad8dc8c040a2..98dc24f5c6f0 100644 > --- a/Documentation/filesystems/f2fs.rst > +++ b/Documentation/filesystems/f2fs.rst > @@ -818,10 +818,11 @@ Compression implementation > 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(F2FS_IOC_RELEASE_COMPRESS_BLOCKS) > - interface to reclaim compressed space and show it to user after putting the > - immutable bit. Immutable bit, after release, it doesn't allow writing/mmaping > - on the file, until reserving compressed space via > - ioctl(F2FS_IOC_RESERVE_COMPRESS_BLOCKS) or truncating filesize to zero. > + interface to reclaim compressed space and show it to user after setting a > + special flag to the inode. Once the compressed space is released, the flag > + will block writing data to the file until either the compressed space is > + reserved via ioctl(F2FS_IOC_RESERVE_COMPRESS_BLOCKS) or the file size is
s/file size/filesize/
Reviewed-by: Chao Yu <chao@kernel.org>
Thanks,
> + truncated to zero. > > Compress metadata layout:: > > @@ -830,12 +831,12 @@ Compress metadata layout:: > | cluster 1 | cluster 2 | ......... | cluster N | > +-----------------------------------------------+ > . . . . > - . . . . > + . . . . > . Compressed Cluster . . Normal Cluster . > +----------+---------+---------+---------+ +---------+---------+---------+---------+ > |compr flag| block 1 | block 2 | block 3 | | block 1 | block 2 | block 3 | block 4 | > +----------+---------+---------+---------+ +---------+---------+---------+---------+ > - . . > + . . > . . > . . > +-------------+-------------+----------+----------------------------+
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