staging: lustre: llite: specify READA debug mask for ras_update

So that debug log only contains relevant messages for debugging
purpose.
Signed-off-by: Bobi Jam <bobijam.xu@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-8413
Reviewed-on: http://review.whamcloud.com/22753Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/llite/rw.c

@@ -729,6 +729,10 @@ static void ras_update(struct ll_sb_info *sbi, struct inode *inode,
 
 	spin_lock(&ras->ras_lock);
 
+	if (!hit)
+		CDEBUG(D_READA, DFID " pages at %lu miss.\n",
+		       PFID(ll_inode2fid(inode)), index);
+
 	ll_ra_stats_inc_sbi(sbi, hit ? RA_STAT_HIT : RA_STAT_MISS);
 
 	/* reset the read-ahead window in two cases.  First when the app seeks