xfs: Initialize variables in xfs_alloc_get_rec before using them

Make sure we initialize *bno and *len, before jumping to out_bad_rec
label, and risk calling xfs_warn() with uninitialized variables.

Coverity: 100898
Coverity: 1437081
Coverity: 1437129
Coverity: 1437191
Coverity: 1437201
Coverity: 1437212
Coverity: 1437341
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/libxfs/xfs_alloc.c

@@ -223,12 +223,13 @@ xfs_alloc_get_rec(
 	error = xfs_btree_get_rec(cur, &rec, stat);
 	if (error || !(*stat))
 		return error;
-	if (rec->alloc.ar_blockcount == 0)
-		goto out_bad_rec;
 
 	*bno = be32_to_cpu(rec->alloc.ar_startblock);
 	*len = be32_to_cpu(rec->alloc.ar_blockcount);
 
+	if (*len == 0)
+		goto out_bad_rec;
+
 	/* check for valid extent range, including overflow */
 	if (!xfs_verify_agbno(mp, agno, *bno))
 		goto out_bad_rec;