linux-kernel - Re: [f2fs-dev][PATCH] f2fs: not allowed to set file both cold and hot

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Message-ID: <ZJXtcfoR+BFx5CXn@google.com>
Date:   Fri, 23 Jun 2023 12:07:29 -0700
From:   Jaegeuk Kim <jaegeuk@...nel.org>
To:     Chao Yu <chao@...nel.org>
Cc:     何云蕾(Yunlei he) <heyunlei@...o.com>,
        linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org
Subject: Re: [f2fs-dev][PATCH] f2fs: not allowed to set file both cold and hot

On 06/20, Chao Yu wrote:
> On 2023/6/20 10:42, 何云蕾(Yunlei he) wrote:
> > 
> > On 2023/6/20 8:33, Chao Yu wrote:
> > > On 2023/6/13 16:52, Yunlei He wrote:
> > > > File set both cold and hot advise bit is confusion, so
> > > > return EINVAL to avoid this case.
> > > > 
> > > > Signed-off-by: Yunlei He <heyunlei@...o.com>
> > > > ---
> > > >   fs/f2fs/xattr.c | 3 +++
> > > >   1 file changed, 3 insertions(+)
> > > > 
> > > > diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
> > > > index 213805d3592c..917f3ac9f1a1 100644
> > > > --- a/fs/f2fs/xattr.c
> > > > +++ b/fs/f2fs/xattr.c
> > > > @@ -127,6 +127,9 @@ static int f2fs_xattr_advise_set(const struct xattr_handler *handler,
> > > >                  return -EINVAL;
> > > > 
> > > >          new_advise = new_advise & FADVISE_MODIFIABLE_BITS;
> > > > +       if ((new_advise & FADVISE_COLD_BIT) && (new_advise & FADVISE_HOT_BIT))
> > > > +               return -EINVAL;

Why not this to allow setting one bit only?

@@ -123,7 +123,8 @@ static int f2fs_xattr_advise_set(const struct xattr_handler *handler,
                return -EINVAL;

        new_advise = *(char *)value;
-       if (new_advise & ~FADVISE_MODIFIABLE_BITS)
+       if (new_advise & ~FADVISE_MODIFIABLE_BITS ||
+           new_advise == FADVISE_MODIFIABLE_BITS)
                return -EINVAL;

> > > 
> > > Yunlei,
> > > 
> > > What about the below case:
> > > 
> > > 1. f2fs_xattr_advise_set(FADVISE_COLD_BIT)
> > > 2. f2fs_xattr_advise_set(FADVISE_HOT_BIT)
> > 
> > Hi,  Chao,
> > 
> >      I test this case work well with this patch,  case below will return -EINVAL:
> > 
> >      f2fs_xattr_advise_set(FADVISE_COLD_BIT | FADVISE_HOT_BIT)
> 
> Correct, I missed to check below statement.
> 
> new_advise |= old_advise & ~FADVISE_MODIFIABLE_BITS;
> 
> Anyway, the patch looks good to me.
> 
> Reviewed-by: Chao Yu <chao@...nel.org>
> 
> Thanks,