[SERVER] Get rid of alt-servers thread, per-uplink rtt history

Alt-Server checks are now run using the threadpool, so we don't need a
queue and dedicated thread anymore. The rtt history is now kept per
uplink, so many uplinks won't overwhelm the history, making its time
window very short.
Also the fail counter is now split up; a global one for when the server
actually isn't reachable, a local (per-uplink) one for when the server
is reachable but doesn't serve the requested image.

1 files changed, 12 insertions, 4 deletions

diff --git a/src/server/net.c b/src/server/net.c
index 7f3c1ce..4976eea 100644
--- a/src/server/net.c
+++ b/src/server/net.c
@@ -669,11 +669,19 @@ static void removeFromList(dnbd3_client_t *client)
 {
 	int i;
 	mutex_lock( &_clients_lock );
-	for ( i = _num_clients - 1; i >= 0; --i ) {
-		if ( _clients[i] == client ) {
-			_clients[i] = NULL;
+	if ( _num_clients != 0 ) {
+		for ( i = _num_clients - 1; i >= 0; --i ) {
+			if ( _clients[i] == client ) {
+				_clients[i] = NULL;
+				break;
+			}
+		}
+		if ( i != 0 && i + 1 == _num_clients ) {
+			do {
+				i--;
+			} while ( _clients[i] == NULL && i > 0 );
+			_num_clients = i + 1;
 		}
-		if ( _clients[i] == NULL && i + 1 == _num_clients ) --_num_clients;
 	}
 	mutex_unlock( &_clients_lock );
 }