[Cluster-devel] [PATCH 11/11] gfs2: Skip gfs2_metatype_check for cached buffers

[Bob Peterson <rpeterso@redhat.com>]

----- Original Message -----
> When reading in buffers from disk, set a new BH_Verify buffer head flag.  In
> gfs2_metatype_check, skip the check if BH_Verify is cleared and clear the
> flag
> when checking.  That way, we'll only check the metatype once when reading
> buffers from disk, and not when the buffers were already in the page cache.
> 
> While touching this code, convert two 'be32_to_cpu(magic) == GFS2_MAGIC'
> checks
> into 'magic == cpu_to_be32(GFS2_MAGIC)'.
> 
> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
> ---
(snip)
>  static inline int gfs2_metatype_check(struct gfs2_sbd *sdp,
> -					struct buffer_head *bh,
> -					u16 type)
> +				      struct buffer_head *bh, u16 type)
>  {
> -	struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;
> -	u32 magic = be32_to_cpu(mh->mh_magic);
> -	u16 t = be32_to_cpu(mh->mh_type);
> -	if (unlikely(magic != GFS2_MAGIC))
> -		return gfs2_meta_check_ii(sdp, bh, "magic number", (void *)_RET_IP_);
> -        if (unlikely(t != type))
> -		return gfs2_metatype_check_ii(sdp, bh, type, t,
> -					      (void *)_RET_IP_);
> -	return 0;
> +	if (!buffer_verify(bh))
> +		return 0;
> +	return gfs2_metatype_check_ii(sdp, bh, type, (void *)_RET_IP_);

May I suggest simplifying with:

if (!test_clear_buffer_verify(bh))
	return 0;

Regards,

Bob Peterson