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From:   Daeho Jeong <daeho43@gmail.com>
Date:   Mon, 31 Aug 2020 08:42:33 +0900
Message-ID: <CACOAw_wc29AROzFhcGyC73i_vYZC1NmHP60uQfP7X-j6y6=kSA@mail.gmail.com>
Subject: Re: [f2fs-dev] [PATCH] f2fs: prevent compressed file from being
 disabled after releasing cblocks
To:     Chao Yu <chao@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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Do you have any reason not to put this check here?
If we do this check outside of here, we definitely make a mistake
sooner or later.

2020=EB=85=84 8=EC=9B=94 30=EC=9D=BC (=EC=9D=BC) =EC=98=A4=ED=9B=84 12:24, =
Chao Yu <chao@kernel.org>=EB=8B=98=EC=9D=B4 =EC=9E=91=EC=84=B1:
>
> On 2020-8-28 13:46, Daeho Jeong wrote:
> > From: Daeho Jeong <daehojeong@google.com>
> >
> > After releasing cblocks, the compressed file can be accidentally
> > disabled in compression mode, since it has zero cblocks. As we are
> > using IMMUTABLE flag to present released cblocks state, we can add
> > IMMUTABLE state check when considering the compressed file disabling.
> >
> > Signed-off-by: Daeho Jeong <daehojeong@google.com>
> > ---
> >  fs/f2fs/f2fs.h | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index 02811ce15059..14d30740ba03 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -3936,6 +3936,8 @@ static inline u64 f2fs_disable_compressed_file(st=
ruct inode *inode)
> >       if (!f2fs_compressed_file(inode))
> >               return 0;
> >       if (S_ISREG(inode->i_mode)) {
> > +             if (IS_IMMUTABLE(inode))
> > +                     return 1;
>
> It looks most of callers are from ioctl, should we add immutable check in=
 f2fs
> ioctl interfaces if necessary? or I missed existed check.
>
> Thanks,
>
> >               if (get_dirty_pages(inode))
> >                       return 1;
> >               if (fi->i_compr_blocks)
> >