ocfs2: convert inode refcount test to a helper

Replace the open-coded inode refcount flag test with a helper function
to reduce the potential for bugs.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index cb157a3..3c5384d 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -2577,7 +2577,7 @@ int ocfs2_xattr_remove(struct inode *inode, struct buffer_head *di_bh)
 	if (!(oi->ip_dyn_features & OCFS2_HAS_XATTR_FL))
 		return 0;
 
-	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_HAS_REFCOUNT_FL) {
+	if (ocfs2_is_refcount_inode(inode)) {
 		ret = ocfs2_lock_refcount_tree(OCFS2_SB(inode->i_sb),
 					       le64_to_cpu(di->i_refcount_loc),
 					       1, &ref_tree, &ref_root_bh);
@@ -3608,7 +3608,7 @@ int ocfs2_xattr_set(struct inode *inode,
 	}
 
 	/* Check whether the value is refcounted and do some preparation. */
-	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_HAS_REFCOUNT_FL &&
+	if (ocfs2_is_refcount_inode(inode) &&
 	    (!xis.not_found || !xbs.not_found)) {
 		ret = ocfs2_prepare_refcount_xattr(inode, di, &xi,
 						   &xis, &xbs, &ref_tree,