diff options
| -rw-r--r-- | src/server/altservers.c | 26 |
1 files changed, 20 insertions, 6 deletions
diff --git a/src/server/altservers.c b/src/server/altservers.c index 35da3a2..1ba75f4 100644 --- a/src/server/altservers.c +++ b/src/server/altservers.c @@ -470,6 +470,11 @@ static void *altservers_runCheck(void *data) void altservers_findUplink(dnbd3_uplink_t *uplink) { altservers_findUplinkInternal( uplink ); + // Above function is sync, which means normally when it + // returns, rttTestResult will not be RTT_INPROGRESS. + // But we might have an ansync call running in parallel, which would + // mean the above call returns immediately. Wait for that check + // to finish too. while ( uplink->rttTestResult == RTT_INPROGRESS ) { usleep( 5000 ); } @@ -530,6 +535,18 @@ static void altservers_findUplinkInternal(dnbd3_uplink_t *uplink) dnbd3_server_connection_t best = { .fd = -1 }; unsigned long bestRtt = RTT_UNREACHABLE; unsigned long currentRtt = RTT_UNREACHABLE; + uint64_t offset = 0; + uint32_t length = DNBD3_BLOCK_SIZE; + // Try to use the range of the first request in the queue as RTT block. + // In case we have a cluster of servers where none of them has a complete + // copy, we at least make sure the one we're potentially switching to + // has the next block we're about to request. + mutex_lock( &uplink->queueLock ); + if ( uplink->queue != NULL ) { + offset = uplink->queue->from; + length = (uint32_t)( uplink->queue->to - offset ); + } + mutex_unlock( &uplink->queueLock ); for (itAlt = 0; itAlt < numAlts; ++itAlt) { int server = servers[itAlt]; // Connect @@ -563,9 +580,9 @@ static void altservers_findUplinkInternal(dnbd3_uplink_t *uplink) if ( imageSize != image->virtualFilesize ) { ERROR_GOTO( image_failed, "[RTT] Remote size: %" PRIu64 ", expected: %" PRIu64, imageSize, image->virtualFilesize ); } - // Request first block (NOT random!) ++++++++++++++++++++++++++++++ - if ( !dnbd3_get_block( sock, 0, DNBD3_BLOCK_SIZE, 0, COND_HOPCOUNT( protocolVersion, 1 ) ) ) { - LOG_GOTO( image_failed, LOG_DEBUG1, "[RTT%d] Could not request first block", server ); + // Request block (NOT random! First or from queue) ++++++++++++ + if ( !dnbd3_get_block( sock, offset, length, 0, COND_HOPCOUNT( protocolVersion, 1 ) ) ) { + LOG_GOTO( image_failed, LOG_DEBUG1, "[RTT%d] Could not request block", server ); } // See if requesting the block succeeded ++++++++++++++++++++++ dnbd3_reply_t reply; @@ -587,9 +604,6 @@ static void altservers_findUplinkInternal(dnbd3_uplink_t *uplink) mutex_lock( &uplink->rttLock ); const bool isCurrent = ( uplink->current.index == server ); mutex_unlock( &uplink->rttLock ); - // Penaltize rtt if this was a cycle; this will treat this server with lower priority - // in the near future too, so we prevent alternating between two servers that are both - // part of a cycle and have the lowest latency. uint32_t rtt = (uint32_t)((end.tv_sec - start.tv_sec) * 1000000 + (end.tv_nsec - start.tv_nsec) / 1000); // µs uint32_t avg = altservers_updateRtt( uplink, server, rtt ); |