Low disk space detector (#277)

* - Feature: Disk writes are now blocked early and return an insufficient storage error if free disk space falls below the `--low-diskspace-threshold` value
* Never keep an entry in m_ChunkBlocks that points to a nullptr

1 files changed, 12 insertions, 10 deletions

diff --git a/src/zenserver/config.h b/src/zenserver/config.h
index 9559cae33..caf4adce7 100644
--- a/src/zenserver/config.h
+++ b/src/zenserver/config.h
@@ -69,11 +69,12 @@ struct ZenUpstreamCacheConfig
 
 struct ZenCacheEvictionPolicy
 {
-	uint64_t DiskSizeLimit		= ~uint64_t(0);
-	uint64_t MemorySizeLimit	= 1024 * 1024 * 1024;
-	int32_t	 MaxDurationSeconds = 24 * 60 * 60;
-	uint64_t DiskSizeSoftLimit	= 0;
-	bool	 Enabled			= true;
+	uint64_t DiskSizeLimit					   = ~uint64_t(0);
+	uint64_t MemorySizeLimit				   = 1024 * 1024 * 1024;
+	int32_t	 MaxDurationSeconds				   = 24 * 60 * 60;
+	uint64_t DiskSizeSoftLimit				   = 0;
+	uint64_t MinimumFreeDiskSpaceToAllowWrites = 256u * 1024u * 1024u;
+	bool	 Enabled						   = true;
 };
 
 struct ZenCasEvictionPolicy
@@ -88,11 +89,12 @@ struct ZenGcConfig
 {
 	ZenCasEvictionPolicy   Cas;
 	ZenCacheEvictionPolicy Cache;
-	int32_t				   MonitorIntervalSeconds = 30;
-	int32_t				   IntervalSeconds		  = 0;
-	bool				   CollectSmallObjects	  = true;
-	bool				   Enabled				  = true;
-	uint64_t			   DiskReserveSize		  = 1ul << 28;
+	int32_t				   MonitorIntervalSeconds			 = 30;
+	int32_t				   IntervalSeconds					 = 0;
+	bool				   CollectSmallObjects				 = true;
+	bool				   Enabled							 = true;
+	uint64_t			   DiskReserveSize					 = 1ul << 28;
+	uint64_t			   MinimumFreeDiskSpaceToAllowWrites = 1ul << 28;
 };
 
 struct ZenOpenIdProviderConfig