Fix a leak in failure exit in 9p ->get_sb()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
index 0d29a57..ab5547f 100644
--- a/fs/9p/vfs_super.c
+++ b/fs/9p/vfs_super.c
@@ -156,6 +156,7 @@
 
 	root = d_alloc_root(inode);
 	if (!root) {
+		iput(inode);
 		retval = -ENOMEM;
 		goto release_sb;
 	}