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/logfs/dir.c b/fs/logfs/dir.c
index 1eb4e89..409dfd6 100644
--- a/fs/logfs/dir.c
+++ b/fs/logfs/dir.c
@@ -569,7 +569,7 @@
 		return -EMLINK;
 
 	inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
-	atomic_inc(&inode->i_count);
+	ihold(inode);
 	inode->i_nlink++;
 	mark_inode_dirty_sync(inode);