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Date: Wed, 20 Dec 2017 07:51:29 +1100
From: Dave Chinner <david@fromorbit.com>
Subject: Re: [PATCH 07/13] xfs: create structure verifier function for
 shortform xattrs
Message-ID: <20171219205129.GA4094@dastard>
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To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: linux-xfs@vger.kernel.org

On Tue, Dec 19, 2017 at 12:41:47PM -0800, Darrick J. Wong wrote:
> On Tue, Dec 19, 2017 at 04:23:29PM +1100, Dave Chinner wrote:
> > On Wed, Dec 13, 2017 at 03:58:55PM -0800, Darrick J. Wong wrote:
> > > From: Darrick J. Wong <darrick.wong@oracle.com>
> > > 
> > > Create a function to perform structure verification for short form
> > > extended attributes.
> > > 
> > > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > > ---
> > > +		/* Check for invalid namespace combinations. */
> > > +		if ((sfep->flags & XFS_ATTR_ROOT) &&
> > > +		    (sfep->flags & XFS_ATTR_SECURE))
> > > +			return __this_address;
> > 
> > #define ATTR_SF_FLAGS	(XFS_ATTR_ROOT | XFS_ATTR_SECURE)
> 
> XFS_ATTR_NSP_ONDISK_MASK?

Yeah, that works. I didn't go looking for an existing definition :/

> > 
> > 		if (sfep->flags & ~ATTR_SF_FLAGS)
> > 			return __this_address;
> > 		if ((sfep->flags & ATTR_SF_FLAGS) == ATTR_SF_FLAGS)
> > 			return __this_address;
> 
> Also, can we just use hweight8() > 1 here?  We only allow one namespace
> bit per attr.

With a comment, yes, otherwise someone unfamiliar with what
hweight() does will have to go do lots of extra work to understand
the code.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com