diff options
| -rw-r--r-- | src/server/uplink.c | 25 |
1 files changed, 20 insertions, 5 deletions
diff --git a/src/server/uplink.c b/src/server/uplink.c index dedaa17..11c9d05 100644 --- a/src/server/uplink.c +++ b/src/server/uplink.c @@ -18,6 +18,8 @@ #include <unistd.h> #include <stdatomic.h> +static const uint8_t HOP_FLAG_BGR = 0x80; +static const uint8_t HOP_FLAG_PREFETCH = 0x40; #define FILE_BYTES_PER_MAP_BYTE ( DNBD3_BLOCK_SIZE * 8 ) #define MAP_BYTES_PER_HASH_BLOCK (int)( HASH_BLOCK_SIZE / FILE_BYTES_PER_MAP_BYTE ) #define MAP_INDEX_HASH_START_MASK ( ~(int)( MAP_BYTES_PER_HASH_BLOCK - 1 ) ) @@ -251,8 +253,8 @@ void uplink_removeEntry(dnbd3_uplink_t *uplink, void *data, uplink_callback call bool uplink_requestClient(dnbd3_client_t *client, uplink_callback callback, uint64_t handle, uint64_t start, uint32_t length, uint8_t hops) { assert( client != NULL && callback != NULL ); - if ( hops > 200 ) { // This is just silly - logadd( LOG_WARNING, "Refusing to relay a request that has > 200 hops" ); + if ( ( hops & 0x3f ) > 60 ) { // This is just silly + logadd( LOG_WARNING, "Refusing to relay a request that has > 60 hops" ); return false; } dnbd3_uplink_t *uplink = ref_get_uplink( &client->image->uplinkref ); @@ -338,6 +340,12 @@ static bool uplink_requestInternal(dnbd3_uplink_t *uplink, void *data, uplink_ca { assert( uplink != NULL ); assert( data == NULL || callback != NULL ); + if ( ( hops & HOP_FLAG_BGR ) // This is a background replication request + && _backgroundReplication != BGR_FULL ) { // Deny if we're not doing BGR + // TODO: Allow BGR_HASHBLOCK too, but only if hash block isn't completely empty + logadd( LOG_DEBUG2, "Dopping client because of BGR policy" ); + return false; + } if ( uplink->shutdown ) { logadd( LOG_DEBUG1, "Uplink request for image with uplink shutting down" ); return false; @@ -348,8 +356,14 @@ static bool uplink_requestInternal(dnbd3_uplink_t *uplink, void *data, uplink_ca return false; } - req_t req, preReq; hops++; + if ( callback == NULL ) { + // Set upper-most bit for replication requests that we fire + // In client mode, at least set prefetch flag to prevent prefetch cascading + hops |= _pretendClient ? HOP_FLAG_PREFETCH : HOP_FLAG_BGR; + } + + req_t req, preReq; dnbd3_queue_entry_t *request = NULL, *last = NULL, *pre = NULL; bool isNew; const uint64_t end = start + length; @@ -447,6 +461,7 @@ static bool uplink_requestInternal(dnbd3_uplink_t *uplink, void *data, uplink_ca // async prefetching in another thread was sometimes so slow that we'd process // another request from the same client before the prefetch job would execute. if ( callback != NULL && ( isNew || request->clients == NULL || request->clients->data == data ) + && !( hops & (HOP_FLAG_BGR | HOP_FLAG_PREFETCH) ) // No cascading of prefetches && end == request->to && length <= _maxPrefetch ) { // Only if this is a client request, and the !! end boundary matches exactly !! // (See above for reason why) @@ -464,7 +479,7 @@ static bool uplink_requestInternal(dnbd3_uplink_t *uplink, void *data, uplink_ca pre->handle = preReq.handle = ++uplink->queueId; pre->from = preReq.start; pre->to = preReq.end; - pre->hopCount = hops; + pre->hopCount = hops | HOP_FLAG_PREFETCH; pre->sent = true; // Optimistic; would be set to false on failure pre->clients = NULL; #ifdef DEBUG @@ -498,7 +513,7 @@ static bool uplink_requestInternal(dnbd3_uplink_t *uplink, void *data, uplink_ca ret1 = requestBlock( uplink, &req, hops ); } if ( pre != NULL ) { - ret2 = requestBlock( uplink, &preReq, hops ); + ret2 = requestBlock( uplink, &preReq, hops | HOP_FLAG_PREFETCH ); } if ( !ret1 || !ret2 ) { // Set with send locked uplink->image->problem.uplink = true; |