new helper: ihold()

Clones an existing reference to inode; caller must already hold one.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/gfs2/ops_inode.c b/fs/gfs2/ops_inode.c
index 48a274f..12cbea7 100644
--- a/fs/gfs2/ops_inode.c
+++ b/fs/gfs2/ops_inode.c
@@ -255,7 +255,7 @@
 	gfs2_holder_uninit(ghs);
 	gfs2_holder_uninit(ghs + 1);
 	if (!error) {
-		atomic_inc(&inode->i_count);
+		ihold(inode);
 		d_instantiate(dentry, inode);
 		mark_inode_dirty(inode);
 	}