Re: [PATCH 6.6] ext4: filesystems without casefold feature cannot be mounted with siphash

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Feb 13, 2025 at 02:53:56PM +0100, Greg KH wrote:
> On Fri, Feb 07, 2025 at 12:37:03PM +0100, vgiraud.opensource@witekio.com wrote:
> > From: Lizhi Xu <lizhi.xu@windriver.com>
> > 
> > commit 985b67cd86392310d9e9326de941c22fc9340eec upstream.
> > 
> > When mounting the ext4 filesystem, if the default hash version is set to
> > DX_HASH_SIPHASH but the casefold feature is not set, exit the mounting.
> > 
> > Reported-by: syzbot+340581ba9dceb7e06fb3@syzkaller.appspotmail.com
> > Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com>
> > Link: https://patch.msgid.link/20240605012335.44086-1-lizhi.xu@windriver.com
> > Signed-off-by: Theodore Ts'o <tytso@mit.edu>
> > Signed-off-by: Bruno VERNAY <bruno.vernay@se.com>
> > Signed-off-by: Victor Giraud <vgiraud.opensource@witekio.com>
> > ---
> >  fs/ext4/super.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> > 
> > diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> > index f019ce64eba4..b69d791be846 100644
> > --- a/fs/ext4/super.c
> > +++ b/fs/ext4/super.c
> > @@ -3627,6 +3627,14 @@ int ext4_feature_set_ok(struct super_block *sb, int readonly)
> >  	}
> >  #endif
> >  
> > +	if (EXT4_SB(sb)->s_es->s_def_hash_version == DX_HASH_SIPHASH &&
> > +	    !ext4_has_feature_casefold(sb)) {
> > +		ext4_msg(sb, KERN_ERR,
> > +			 "Filesystem without casefold feature cannot be "
> > +			 "mounted with siphash");
> > +		return 0;
> > +	}
> > +
> >  	if (readonly)
> >  		return 1;
> >  
> > -- 
> > 2.34.1
> > 
> > 
> 
> Any specific reason you asked for just this one commit to be backported
> and NOT the fix for this commit?
> 
> How did you test this?

And the fix did not apply either, so I'm dropping this from all queues.

Be more careful please!  Don't submit patches that actually cause
documented problems.

greg k-h