afs: Don't get epoch from a server because it may be ambiguous

Don't get the epoch from a server, particularly one that we're looking up
by UUID, as UUIDs may be ambiguous and may map to more than one server - so
we can't draw any conclusions from it.

Reported-by: Jeffrey Altman <[e-mail]>
Signed-off-by: David Howells <[e-mail]>

fs/afs/cmservice.c

···
 {
 	_enter("{%u, CB.OP %u}", call->service_id, call->operation_ID);
 
-	call->epoch = rxrpc_kernel_get_epoch(call->net->socket, call->rxcall);
-
 	switch (call->operation_ID) {
 	case CBCallBack:
 		call->type = &afs_SRXCBCallBack;
···
 }
 
 /*
- * Record a probe to the cache manager from a server.
- */
-static int afs_record_cm_probe(struct afs_call *call, struct afs_server *server)
-{
-	_enter("");
-
-	if (test_bit(AFS_SERVER_FL_HAVE_EPOCH, &server->flags) &&
-	    !afs_is_probing_server(server)) {
-		if (server->cm_epoch == call->epoch)
-			return 0;
-
-		if (!server->probe.said_rebooted) {
-			pr_notice("kAFS: FS rebooted %pU\n", &server->uuid);
-			server->probe.said_rebooted = true;
-		}
-	}
-
-	spin_lock(&server->probe_lock);
-
-	if (!test_and_set_bit(AFS_SERVER_FL_HAVE_EPOCH, &server->flags)) {
-		server->cm_epoch = call->epoch;
-		server->probe.cm_epoch = call->epoch;
-		goto out;
-	}
-
-	if (server->probe.cm_probed &&
-	    call->epoch != server->probe.cm_epoch &&
-	    !server->probe.said_inconsistent) {
-		pr_notice("kAFS: FS endpoints inconsistent %pU\n",
-			  &server->uuid);
-		server->probe.said_inconsistent = true;
-	}
-
-	if (!server->probe.cm_probed || call->epoch == server->cm_epoch)
-		server->probe.cm_epoch = server->cm_epoch;
-
-out:
-	server->probe.cm_probed = true;
-	spin_unlock(&server->probe_lock);
-	return 0;
-}
-
-/*
  * Find the server record by peer address and record a probe to the cache
  * manager from a server.
  */
···
 	}
 
 	call->server = server;
-	return afs_record_cm_probe(call, server);
+	return 0;
 }
 
 /*
···
 	}
 
 	call->server = server;
-	return afs_record_cm_probe(call, server);
+	return 0;
 }
 
 /*

fs/afs/internal.h

···
 	spinlock_t		state_lock;
 	int			error;		/* error code */
 	u32			abort_code;	/* Remote abort ID or 0 */
-	u32			epoch;
 	unsigned int		max_lifespan;	/* Maximum lifespan to set if not 0 */
 	unsigned		request_size;	/* size of request data */
 	unsigned		reply_max;	/* maximum size of reply */
···
 #define AFS_SERVER_FL_MAY_HAVE_CB 8		/* May have callbacks on this fileserver */
 #define AFS_SERVER_FL_IS_YFS	9		/* Server is YFS not AFS */
 #define AFS_SERVER_FL_NO_RM2	10		/* Fileserver doesn't support YFS.RemoveFile2 */
-#define AFS_SERVER_FL_HAVE_EPOCH 11		/* ->epoch is valid */
 #define AFS_SERVER_FL_NEEDS_UPDATE 12		/* Fileserver address list is out of date */
 	atomic_t		ref;		/* Object refcount */
 	atomic_t		active;		/* Active user count */
 	u32			addr_version;	/* Address list version */
-	u32			cm_epoch;	/* Server RxRPC epoch */
 	unsigned int		debug_id;	/* Debugging ID for traces */
 
 	/* file service access */
···
 	struct {
 		unsigned int	rtt;		/* RTT as ktime/64 */
 		u32		abort_code;
-		u32		cm_epoch;
 		short		error;
 		bool		responded:1;
 		bool		is_yfs:1;
 		bool		not_yfs:1;
 		bool		local_failure:1;
-		bool		cm_probed:1;
-		bool		said_rebooted:1;
-		bool		said_inconsistent:1;
 	} probe;
 };