diff options
Diffstat (limited to 'src/server/uplink.c')
| -rw-r--r-- | src/server/uplink.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/src/server/uplink.c b/src/server/uplink.c index 2821a27..5b05873 100644 --- a/src/server/uplink.c +++ b/src/server/uplink.c @@ -455,16 +455,24 @@ static void uplink_send_requests(dnbd3_connection_t *link, int newOnly) } /** - * Sent a block request to an uplink server without really having - * any client that needs that data. This will be used for background replication + * Send a block request to an uplink server without really having + * any client that needs that data. This will be used for background replication. + * + * We'll go through the cache map of the image and look for bytes that don't have + * all bits set. We then request the corresponding 8 blocks of 4kb from the uplink + * server. This means we might request data we already have, but it makes + * the code simpler. Worst case would be only one bit is zero, which means + * 4kb are missing, but we will request 32kb. */ static void uplink_sendReplicationRequest(dnbd3_connection_t *link) { + if ( !_backgroundReplication ) return; // Don't do background replication if ( link == NULL || link->fd == -1 ) return; dnbd3_image_t * const image = link->image; - if ( image == NULL || image->cache_map == NULL || image->filesize < DNBD3_BLOCK_SIZE ) return; + if ( image->filesize < DNBD3_BLOCK_SIZE ) return; spin_lock( &image->lock ); if ( image == NULL || image->cache_map == NULL || link->replicationHandle != 0 ) { + // No cache map (=image complete), or replication pending, do nothing spin_unlock( &image->lock ); return; } @@ -474,7 +482,7 @@ static void uplink_sendReplicationRequest(dnbd3_connection_t *link) for (int i = 0; i <= len; ++i) { if ( image->cache_map == NULL || link->fd == -1 ) break; if ( image->cache_map[i] == 0xff || (i == len && link->replicatedLastBlock) ) continue; - if ( i == len ) link->replicatedLastBlock = TRUE; + if ( i == len ) link->replicatedLastBlock = TRUE; // Special treatment, last byte in map could represent less than 8 blocks link->replicationHandle = 1; // Prevent race condition spin_unlock( &image->lock ); // Unlocked - do not break or continue here... |