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From:   Daeho Jeong <daeho43@gmail.com>
Date:   Tue, 24 Nov 2020 08:02:21 +0900
Message-ID: <CACOAw_xEe=3H60njSfwJSToFnVbOHabUd2Nt=uZJLvCfxFgM4Q@mail.gmail.com>
Subject: Re: [f2fs-dev] [PATCH 2/2] f2fs: add F2FS_IOC_DECOMPRESS_FILE and F2FS_IOC_COMPRESS_FILE
To:     Eric Biggers <ebiggers@kernel.org>
Cc:     linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com,
        Daeho Jeong <daehojeong@google.com>
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Jaegeuk,

My mistake~

Eric,

What I want is like do_page_cache_ra(), but I used
page_cache_ra_unbounded() directly, because we already checked that
read is within i_size.
Or we could use do_page_cache_ra(), but it might do the same check in it ag=
ain.
What do you think?

I could add some description about these in
Documentation/filesystems/f2fs.rst and I implemented tests internally.

2020=EB=85=84 11=EC=9B=94 24=EC=9D=BC (=ED=99=94) =EC=98=A4=EC=A0=84 3:48, =
Eric Biggers <ebiggers@kernel.org>=EB=8B=98=EC=9D=B4 =EC=9E=91=EC=84=B1:
>
> On Mon, Nov 23, 2020 at 12:17:51PM +0900, Daeho Jeong wrote:
> > From: Daeho Jeong <daehojeong@google.com>
> >
> > Added two ioctl to decompress/compress explicitly the compression
> > enabled file in "compress_mode=3Duser-based" mount option.
> >
> > Using these two ioctls, the users can make a control of compression
> > and decompression of their files.
> >
> > Signed-off-by: Daeho Jeong <daehojeong@google.com>
> > ---
> >  fs/f2fs/file.c            | 181 +++++++++++++++++++++++++++++++++++++-
> >  include/uapi/linux/f2fs.h |   2 +
> >  2 files changed, 182 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > index be8db06aca27..e8f142470e87 100644
> > --- a/fs/f2fs/file.c
> > +++ b/fs/f2fs/file.c
> > @@ -4026,6 +4026,180 @@ static int f2fs_ioc_set_compress_option(struct =
file *filp, unsigned long arg)
> >       return ret;
> >  }
> >
> > +static int redirty_blocks(struct inode *inode, pgoff_t page_idx, int l=
en)
> > +{
> > +     DEFINE_READAHEAD(ractl, NULL, inode->i_mapping, page_idx);
> > +     struct f2fs_sb_info *sbi =3D F2FS_I_SB(inode);
> > +     struct address_space *mapping =3D inode->i_mapping;
> > +     struct page *page;
> > +     pgoff_t redirty_idx =3D page_idx;
> > +     int i, page_len =3D 0, ret =3D 0;
> > +
> > +     page_cache_ra_unbounded(&ractl, len, 0);
>
> Using page_cache_ra_unbounded() here looks wrong.  See the comment above
> page_cache_ra_unbounded().
>
> >  static long __f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned=
 long arg)
> >  {
> >       switch (cmd) {
> > @@ -4113,6 +4287,10 @@ static long __f2fs_ioctl(struct file *filp, unsi=
gned int cmd, unsigned long arg)
> >               return f2fs_ioc_get_compress_option(filp, arg);
> >       case F2FS_IOC_SET_COMPRESS_OPTION:
> >               return f2fs_ioc_set_compress_option(filp, arg);
> > +     case F2FS_IOC_DECOMPRESS_FILE:
> > +             return f2fs_ioc_decompress_file(filp, arg);
> > +     case F2FS_IOC_COMPRESS_FILE:
> > +             return f2fs_ioc_compress_file(filp, arg);
> >       default:
> >               return -ENOTTY;
> >       }
>
> Where is the documentation and tests for these new ioctls?
>
> - Eric