linux-kernel - Re: [f2fs-dev] [PATCH] f2fs: prevent compressed file from being disabled after releasing cblocks

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Date:   Mon, 31 Aug 2020 08:42:33 +0900
From:   Daeho Jeong <daeho43@...il.com>
To:     Chao Yu <chao@...nel.org>
Cc:     linux-kernel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net, kernel-team@...roid.com,
        Daeho Jeong <daehojeong@...gle.com>
Subject: Re: [f2fs-dev] [PATCH] f2fs: prevent compressed file from being
 disabled after releasing cblocks

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.

2020년 8월 30일 (일) 오후 12:24, Chao Yu <chao@...nel.org>님이 작성:
>
> On 2020-8-28 13:46, Daeho Jeong wrote:
> > From: Daeho Jeong <daehojeong@...gle.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@...gle.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(struct 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)
> >