take bdi setup/destruction into cifs_mount/cifs_umount

Acked-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 12cf72d..78fd755 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2983,6 +2983,13 @@
 	struct tcon_link *tlink;
 #ifdef CONFIG_CIFS_DFS_UPCALL
 	int referral_walks_count = 0;
+
+	rc = bdi_setup_and_register(&cifs_sb->bdi, "cifs", BDI_CAP_MAP_COPY);
+	if (rc)
+		return rc;
+
+	cifs_sb->bdi.ra_pages = default_backing_dev_info.ra_pages;
+
 try_mount_again:
 	/* cleanup activities if we're chasing a referral */
 	if (referral_walks_count) {
@@ -3007,6 +3014,7 @@
 	srvTcp = cifs_get_tcp_session(volume_info);
 	if (IS_ERR(srvTcp)) {
 		rc = PTR_ERR(srvTcp);
+		bdi_destroy(&cifs_sb->bdi);
 		goto out;
 	}
 
@@ -3161,6 +3169,7 @@
 			cifs_put_smb_ses(pSesInfo);
 		else
 			cifs_put_tcp_session(srvTcp);
+		bdi_destroy(&cifs_sb->bdi);
 		goto out;
 	}
 
@@ -3357,6 +3366,7 @@
 	}
 	spin_unlock(&cifs_sb->tlink_tree_lock);
 
+	bdi_destroy(&cifs_sb->bdi);
 	return 0;
 }