Merge tag '5.16-rc3-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs fixes from Steve French:
 "Three SMB3 multichannel/fscache fixes and a DFS fix.

  In testing multichannel reconnect scenarios recently various problems
  with the cifs.ko implementation of fscache were found (e.g. incorrect
  initialization of fscache cookies in some cases)"

* tag '5.16-rc3-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: avoid use of dstaddr as key for fscache client cookie
  cifs: add server conn_id to fscache client cookie
  cifs: wait for tcon resource_id before getting fscache super
  cifs: fix missed refcounting of ipc tcon

fs/cifs/connect.c

@@ -1562,6 +1562,10 @@ cifs_get_tcp_session(struct smb3_fs_context *ctx,
 	/* fscache server cookies are based on primary channel only */
 	if (!CIFS_SERVER_IS_CHAN(tcp_ses))
 		cifs_fscache_get_client_cookie(tcp_ses);
+#ifdef CONFIG_CIFS_FSCACHE
+	else
+		tcp_ses->fscache = tcp_ses->primary_server->fscache;
+#endif /* CONFIG_CIFS_FSCACHE */
 
 	/* queue echo request delayed work */
 	queue_delayed_work(cifsiod_wq, &tcp_ses->echo, tcp_ses->echo_interval);
@@ -3046,12 +3050,6 @@ static int mount_get_conns(struct mount_ctx *mnt_ctx)
 				cifs_dbg(VFS, "read only mount of RW share\n");
 			/* no need to log a RW mount of a typical RW share */
 		}
-		/*
-		 * The cookie is initialized from volume info returned above.
-		 * Inside cifs_fscache_get_super_cookie it checks
-		 * that we do not get super cookie twice.
-		 */
-		cifs_fscache_get_super_cookie(tcon);
 	}
 
 	/*
@@ -3426,6 +3424,7 @@ static int connect_dfs_root(struct mount_ctx *mnt_ctx, struct dfs_cache_tgt_list
 	 */
 	mount_put_conns(mnt_ctx);
 	mount_get_dfs_conns(mnt_ctx);
+	set_root_ses(mnt_ctx);
 
 	full_path = build_unc_path_to_root(ctx, cifs_sb, true);
 	if (IS_ERR(full_path))

fs/cifs/fscache.c

@@ -16,14 +16,7 @@
  * Key layout of CIFS server cache index object
  */
 struct cifs_server_key {
-	struct {
-		uint16_t	family;		/* address family */
-		__be16		port;		/* IP port */
-	} hdr;
-	union {
-		struct in_addr	ipv4_addr;
-		struct in6_addr	ipv6_addr;
-	};
+	__u64 conn_id;
 } __packed;
 
 /*
@@ -31,42 +24,23 @@ struct cifs_server_key {
  */
 void cifs_fscache_get_client_cookie(struct TCP_Server_Info *server)
 {
-	const struct sockaddr *sa = (struct sockaddr *) &server->dstaddr;
-	const struct sockaddr_in *addr = (struct sockaddr_in *) sa;
-	const struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *) sa;
 	struct cifs_server_key key;
-	uint16_t key_len = sizeof(key.hdr);
-
-	memset(&key, 0, sizeof(key));
 
 	/*
-	 * Should not be a problem as sin_family/sin6_family overlays
-	 * sa_family field
+	 * Check if cookie was already initialized so don't reinitialize it.
+	 * In the future, as we integrate with newer fscache features,
+	 * we may want to instead add a check if cookie has changed
 	 */
-	key.hdr.family = sa->sa_family;
-	switch (sa->sa_family) {
-	case AF_INET:
-		key.hdr.port = addr->sin_port;
-		key.ipv4_addr = addr->sin_addr;
-		key_len += sizeof(key.ipv4_addr);
-		break;
-
-	case AF_INET6:
-		key.hdr.port = addr6->sin6_port;
-		key.ipv6_addr = addr6->sin6_addr;
-		key_len += sizeof(key.ipv6_addr);
-		break;
-
-	default:
-		cifs_dbg(VFS, "Unknown network family '%d'\n", sa->sa_family);
-		server->fscache = NULL;
+	if (server->fscache)
 		return;
-	}
+
+	memset(&key, 0, sizeof(key));
+	key.conn_id = server->conn_id;
 
 	server->fscache =
 		fscache_acquire_cookie(cifs_fscache_netfs.primary_index,
 				       &cifs_fscache_server_index_def,
-				       &key, key_len,
+				       &key, sizeof(key),
 				       NULL, 0,
 				       server, 0, true);
 	cifs_dbg(FYI, "%s: (0x%p/0x%p)\n",
@@ -92,7 +66,7 @@ void cifs_fscache_get_super_cookie(struct cifs_tcon *tcon)
 	 * In the future, as we integrate with newer fscache features,
 	 * we may want to instead add a check if cookie has changed
 	 */
-	if (tcon->fscache == NULL)
+	if (tcon->fscache)
 		return;
 
 	sharename = extract_sharename(tcon->treeName);

fs/cifs/inode.c

@@ -1376,6 +1376,13 @@ struct inode *cifs_root_iget(struct super_block *sb)
 		inode = ERR_PTR(rc);
 	}
 
+	/*
+	 * The cookie is initialized from volume info returned above.
+	 * Inside cifs_fscache_get_super_cookie it checks
+	 * that we do not get super cookie twice.
+	 */
+	cifs_fscache_get_super_cookie(tcon);
+
 out:
 	kfree(path);
 	free_xid(xid);