Re: [PATCH v2] docs: filesystems: f2fs: fix description about compress ioctl

From: Chao Liu
Date: Mon Jun 13 2022 - 04:02:28 EST


On Mon, Jun 13, 2022 at 04:37:01AM +0100, Matthew Wilcox wrote:
> On Mon, Jun 13, 2022 at 10:08:00AM +0800, Chao Liu wrote:
> > v2:
> > - s/file size/filesize/
>
> Why would you change it to be wrong?
>

This is a suggestion from Chao Yu. Maybe he has some other considerations.

Hi Chao,

Can you help with this question?

Thanks.

> > 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..531b0f8a3946 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 filesize is
> > + 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 |
> > +----------+---------+---------+---------+ +---------+---------+---------+---------+
> > - . .
> > + . .
> > . .
> > . .
> > +-------------+-------------+----------+----------------------------+
> > --
> > 2.36.1
> >