issue-4138: Fix downsizing of a multishard filesystem to a size that less ShardAllocationUnit if StrictFileSystemSizeEnforcementEnabled (#4574)

Fix downsizing of a multisharded filesystem to a size that less than
ShardAllocationUnit if StrictFileSystemSizeEnforcementEnabled

Author: ruslan-gar

cloud/filestore/libs/storage/service/service_actor_alterfs.cpp

@@ -324,15 +324,14 @@ void TAlterFileStoreActor::HandleDescribeFileStoreResponse(
         FileStoreConfig.MainFileSystemConfig.SetVersion(version);
     }
 
-    FileStoreConfig.MainFileSystemConfig.ClearBlockSize();
-
     GetFileSystemTopology(ctx);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 
 void TAlterFileStoreActor::AlterFileStore(const TActorContext& ctx)
 {
+    FileStoreConfig.MainFileSystemConfig.ClearBlockSize();
     FileStoreConfig.MainFileSystemConfig.SetAlterTs(ctx.Now().MicroSeconds());
     auto request = std::make_unique<TEvSSProxy::TEvAlterFileStoreRequest>(
         FileStoreConfig.MainFileSystemConfig);
@@ -446,17 +445,16 @@ void TAlterFileStoreActor::HandleGetFileSystemTopologyResponse(
                 MakeError(E_ARGUMENT, "Cannot decrease number of shards"));
             return;
         } else {
-            // In strict mode we just resize all the shards
-            const auto oldSize = FileStoreConfig.ShardConfigs.size();
-            Y_ABORT_UNLESS(oldSize);
-            FileStoreConfig.ShardConfigs.resize(ExistingShardIds.size());
-            for (auto i = oldSize; i < FileStoreConfig.ShardConfigs.size(); ++i)
-            {
-                FileStoreConfig.ShardConfigs[i] =
-                    FileStoreConfig.ShardConfigs[oldSize - 1];
-                FileStoreConfig.ShardConfigs[i].SetFileSystemId(
-                    ExistingShardIds[i]);
-            }
+            // We can't reduce shards count but in strict mode we should resize
+            // all the shards to have the same size as the main filesystem.
+            // So, FileStoreConfig.ShardConfigs should have the same size as
+            // ExistingShardIds.
+            FileStoreConfig.ShardConfigs.clear();
+            FileStoreConfig = SetupMultiShardFileStorePerformanceAndChannels(
+                *StorageConfig,
+                FileStoreConfig.MainFileSystemConfig,
+                PerformanceProfile,
+                ExistingShardIds.size());
         }
     }
 
@@ -509,6 +507,16 @@ void TAlterFileStoreActor::HandleGetFileSystemTopologyResponse(
             ShardsToAlter == 0 && ShardsToDescribe == 0 &&
             !ShouldConfigureMainFileStore);
 
+        if (StrictFileSystemSizeEnforcementEnabled) {
+            ReplyAndDie(
+                ctx,
+                MakeError(
+                    E_ARGUMENT,
+                    "Cannot change shard size if "
+                    "'StrictFileSystemSizeEnforcementEnabled'"));
+            return;
+        }
+
         FileStoreConfig.ShardConfigs.clear();
 
     } else {

cloud/filestore/libs/storage/service/service_ut_sharding.cpp

@@ -89,6 +89,32 @@ NProtoPrivate::TGetStorageStatsResponse GetStorageStats(
     return response;
 }
 
+void CheckShardsSize(
+    const TShardedFileSystemConfig& fsConfig,
+    TServiceClient& service,
+    const ui64 blocksCount)
+{
+    const auto mainStats =
+        GetStorageStats(service, fsConfig.FsId, false /* allowCache */);
+    const auto shard1Stats = GetStorageStats(
+        service,
+        fsConfig.Shard1Id,
+        false /* allowCache */,
+        NProtoPrivate::STATS_REQUEST_MODE_FORCE_FETCH_SHARDS);
+    const auto shard2Stats = GetStorageStats(
+        service,
+        fsConfig.Shard2Id,
+        false /* allowCache */,
+        NProtoPrivate::STATS_REQUEST_MODE_FORCE_FETCH_SHARDS);
+    UNIT_ASSERT_EQUAL(blocksCount, mainStats.GetStats().GetTotalBlocksCount());
+    UNIT_ASSERT_EQUAL(
+        blocksCount,
+        shard1Stats.GetStats().GetTotalBlocksCount());
+    UNIT_ASSERT_EQUAL(
+        blocksCount,
+        shard2Stats.GetStats().GetTotalBlocksCount());
+}
+
 }   // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -2548,35 +2574,10 @@ Y_UNIT_TEST_SUITE(TStorageServiceShardingTest)
             UNIT_ASSERT_EQUAL(2, shard2Topology.ShardFileSystemIdsSize());
         }
 
-        auto checkShardsSize = [&](const ui64 blocksCount)
-        {
-            const auto mainStats =
-                GetStorageStats(service, fsConfig.FsId, false /* allowCache */);
-            const auto shard1Stats = GetStorageStats(
-                service,
-                fsConfig.Shard1Id,
-                false /* allowCache */,
-                NProtoPrivate::STATS_REQUEST_MODE_FORCE_FETCH_SHARDS);
-            const auto shard2Stats = GetStorageStats(
-                service,
-                fsConfig.Shard2Id,
-                false /* allowCache */,
-                NProtoPrivate::STATS_REQUEST_MODE_FORCE_FETCH_SHARDS);
-            UNIT_ASSERT_EQUAL(
-                blocksCount,
-                mainStats.GetStats().GetTotalBlocksCount());
-            UNIT_ASSERT_EQUAL(
-                blocksCount,
-                shard1Stats.GetStats().GetTotalBlocksCount());
-            UNIT_ASSERT_EQUAL(
-                blocksCount,
-                shard2Stats.GetStats().GetTotalBlocksCount());
-        };
-
         // After resizing and turning on StrictFileSystemSizeEnforcement every
         // shard should have the same TotalBytesCount equal to that of the main
         // filesystem
-        checkShardsSize(fsConfig.MainFsBlockCount());
+        CheckShardsSize(fsConfig, service, fsConfig.MainFsBlockCount());
 
         // Downsize the filesystem by force
         const auto newBlocksCount = fsConfig.MainFsBlockCount() / 2;
@@ -2585,7 +2586,7 @@ Y_UNIT_TEST_SUITE(TStorageServiceShardingTest)
             newBlocksCount,
             true /* force */);
 
-        checkShardsSize(newBlocksCount);
+        CheckShardsSize(fsConfig, service, newBlocksCount);
 
         // Attempt to write one more file should fail
         const auto file = createFile("notEnoughSpace");
@@ -2598,6 +2599,32 @@ Y_UNIT_TEST_SUITE(TStorageServiceShardingTest)
             GenerateValidateData(fileSize, 0xBADF00D));
     }
 
+    SERVICE_TEST_SIMPLE(
+        ShouldResizeShardsInStrictWithStrictFileSystemSizeEnforcement)
+    {
+        // Create file system with two shards 1000 * 4 * 1024 bytes each
+        config.SetMultiTabletForwardingEnabled(true);
+        config.SetStrictFileSystemSizeEnforcementEnabled(true);
+        TShardedFileSystemConfig fsConfig;
+        CREATE_ENV_AND_SHARDED_FILESYSTEM();
+
+        // Downsize the filesystem by force to a size that less than
+        // ShardAllocationUnit
+        const auto newBlocksCount = config.GetShardAllocationUnit() / 2;
+        service.ResizeFileStore(
+            fsConfig.FsId,
+            newBlocksCount,
+            true /* force */);
+
+        CheckShardsSize(fsConfig, service, newBlocksCount);
+
+        // It is prohibited to resize an individual shard if
+        // StrictFileSystemSizeEnforcementEnabled
+        service.AssertResizeFileStoreFailed(
+            fsConfig.Shard1Id,
+            newBlocksCount * 2);
+    }
+
     SERVICE_TEST_SIMPLE(ShouldRetryFileSystemResize)
     {
         // Create a filsystem with two shards.