issue #196: implemented block checksum calculation and verification f…

…or the blobs stored in blobstorage (#278)

* issue #196: implemented calculation of block checksums in the blobs stored in blobstorage; implemented checksum checking for those blobs upon read; enabled this logic for the first 1GiB of the disk space in most of the uts in part_ut and in tests/loadtest/local large test suite; will add the uts that directly check checksum verification is the next PR;

* issue #196: review-related cleanup;

* issue #196: more review-related cleanup;

* issue #196: added a ut with CheckBlockChecksumsInBlobsUponRead, fixed a bug in block verification in ReadBlocks data path, enabled CheckBlockChecksumsInBlobsUponRead in tests/loadtest/local

* issue #196: added more uts

cloud/blockstore/config/storage.proto

@@ -893,4 +893,19 @@ message TStorageServiceConfig
     // Max value is selected between this limit and
     // MaxNonReplicatedDeviceMigrationsInProgress.
     optional uint32 MaxNonReplicatedDeviceMigrationPercentageInProgress = 343;
+
+    // Create shadow disks for checkpoints for DiskRegistry-based disks.
+    optional bool UseShadowDisksForNonreplDiskCheckpoints = 344;
+
+    // Calculate crc32c checksums for blocks in the half-interval [0, X) upon
+    // write and store these checksums in local db.
+    // Affects only blobstorage-based disks.
+    optional uint64 DiskPrefixLengthWithBlockChecksumsInBlobs = 345;
+
+    // Read BlobMeta upon ReadBlocks, calculate crc32c checksums for the fetched
+    // blocks and compare these checksums to the checksums from BlobMeta.
+    //
+    // IMPORTANT: Compaction verifies block checksums for the blocks affected by
+    // it regardless of this flag!
+    optional bool CheckBlockChecksumsInBlobsUponRead = 346;
 }

cloud/blockstore/libs/diagnostics/block_digest.cpp

@@ -13,6 +13,19 @@ namespace NCloud::NBlockStore {
 
 ////////////////////////////////////////////////////////////////////////////////
 
+ui32 ComputeDefaultDigest(TBlockDataRef blockContent)
+{
+    Y_DEBUG_ABORT_UNLESS(blockContent.Data() != nullptr);
+
+    if (blockContent.Data() != nullptr) {
+        return Crc32c(blockContent.Data(), blockContent.Size());
+    }
+
+    return 0;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
 struct TExt4BlockDigestGenerator final
     : IBlockDigestGenerator
 {
@@ -38,7 +51,7 @@ struct TExt4BlockDigestGenerator final
         }
 
         if (blockContent.Data() != nullptr) {
-            return Crc32c(blockContent.Data(), blockContent.Size());
+            return ComputeDefaultDigest(blockContent);
         }
 
         double idx = log2(static_cast<double>(blockContent.Size()) / DefaultBlockSize);

cloud/blockstore/libs/diagnostics/block_digest.h

@@ -30,4 +30,8 @@ IBlockDigestGeneratorPtr CreateExt4BlockDigestGenerator(
 IBlockDigestGeneratorPtr CreateTestBlockDigestGenerator();
 IBlockDigestGeneratorPtr CreateBlockDigestGeneratorStub();
 
+////////////////////////////////////////////////////////////////////////////////
+
+ui32 ComputeDefaultDigest(TBlockDataRef blockContent);
+
 }   // namespace NCloud::NBlockStore

cloud/blockstore/libs/diagnostics/block_digest_ut.cpp

@@ -94,6 +94,11 @@ Y_UNIT_TEST_SUITE(TBlockDigestGeneratorTest)
         UNIT_ASSERT(!gen->ShouldProcess(0, 10, 4_KB));
         UNIT_ASSERT(!gen->ShouldProcess(100500, 10, 4_KB));
     }
+
+    Y_UNIT_TEST(TestComputeDefaultDigest)
+    {
+        UNIT_ASSERT_VALUES_EQUAL(3387363646, ComputeDefaultDigest({"vasya", 5}));
+    }
 }
 
 }   // namespace NCloud::NBlockStore

cloud/blockstore/libs/diagnostics/critical_events.h

@@ -53,6 +53,7 @@ namespace NCloud::NBlockStore {
     xxx(EndpointSwitchFailure)                                                 \
     xxx(DiskAgentSessionCacheUpdateError)                                      \
     xxx(DiskAgentSessionCacheRestoreError)                                     \
+    xxx(BlockDigestMismatchInBlob)                                             \
 // BLOCKSTORE_CRITICAL_EVENTS
 
 #define BLOCKSTORE_IMPOSSIBLE_EVENTS(xxx)                                      \

cloud/blockstore/libs/storage/core/block_handler.cpp

@@ -123,6 +123,23 @@ class TReadBlocksHandler final
         return SgList.Create(std::move(sglist));
     }
 
+    TGuardedSgList GetGuardedSgList(
+        const TVector<ui64>& blockIndices) const override
+    {
+        TSgList sglist(Reserve(blockIndices.size()));
+
+        for (const auto blockIndex: blockIndices) {
+            Y_ABORT_UNLESS(ReadRange.Contains(blockIndex));
+
+            size_t index = blockIndex - ReadRange.Start;
+            Y_ABORT_UNLESS(index < Blocks.BuffersSize());
+            const auto& block = Blocks.GetBuffers(index);
+            sglist.emplace_back(block.data(), BlockSize);
+        }
+
+        return SgList.Create(std::move(sglist));
+    }
+
     bool SetBlock(
         ui64 blockIndex,
         TBlockDataRef blockContent,
@@ -284,6 +301,25 @@ class TReadBlocksLocalHandler final
         return GuardedSgList;
     }
 
+    TGuardedSgList GetGuardedSgList(
+        const TVector<ui64>& blockIndices) const override
+    {
+        if (auto guard = GuardedSgList.Acquire()) {
+            const auto& src = guard.Get();
+            TSgList subset(Reserve(blockIndices.size()));
+
+            for (auto blockIndex: blockIndices) {
+                Y_ABORT_UNLESS(ReadRange.Contains(blockIndex));
+                const auto index = blockIndex - ReadRange.Start;
+                subset.push_back(src[index]);
+            }
+
+            return GuardedSgList.Create(std::move(subset));
+        }
+
+        return GuardedSgList;
+    }
+
     bool SetBlock(
         ui64 blockIndex,
         TBlockDataRef blockContent,

cloud/blockstore/libs/storage/core/block_handler.h

@@ -24,10 +24,16 @@ struct IReadBlocksHandler
 {
     virtual ~IReadBlocksHandler() = default;
 
+    // TODO: split into multiple funcs:
+    // * void SetUnencryptedBlockMaskBits(const TVector<ui64>& blockIndices, bool value)
+    // * TGuardedSgList InitializeBuffers(const TVector<ui64>& blockIndices)
     virtual TGuardedSgList GetGuardedSgList(
         const TVector<ui64>& blockIndices,
         bool baseDisk) = 0;
 
+    virtual TGuardedSgList GetGuardedSgList(
+        const TVector<ui64>& blockIndices) const = 0;
+
     virtual bool SetBlock(
         ui64 blockIndex,
         TBlockDataRef blockContent,

cloud/blockstore/libs/storage/core/config.cpp

@@ -457,6 +457,11 @@ TDuration MSeconds(ui32 value)
     xxx(AssignIdToWriteAndZeroRequestsEnabled,     bool,      false           )\
                                                                                \
     xxx(AgentListExpiredParamsCleanupInterval,     TDuration, Seconds(1)      )\
+                                                                               \
+    xxx(UseShadowDisksForNonreplDiskCheckpoints,   bool,      false           )\
+                                                                               \
+    xxx(DiskPrefixLengthWithBlockChecksumsInBlobs, ui64,      0               )\
+    xxx(CheckBlockChecksumsInBlobsUponRead,        bool,      false           )\
 // BLOCKSTORE_STORAGE_CONFIG_RW
 
 #define BLOCKSTORE_STORAGE_CONFIG(xxx)                                         \

cloud/blockstore/libs/storage/core/config.h

@@ -517,6 +517,11 @@ class TStorageConfig
     TDuration GetAgentListExpiredParamsCleanupInterval() const;
 
     ui64 GetTenantHiveTabletId() const;
+
+    bool GetUseShadowDisksForNonreplDiskCheckpoints() const;
+
+    ui64 GetDiskPrefixLengthWithBlockChecksumsInBlobs() const;
+    bool GetCheckBlockChecksumsInBlobsUponRead() const;
 };
 
 ui64 GetAllocationUnit(

cloud/blockstore/libs/storage/partition/part_actor.cpp

@@ -1,5 +1,6 @@
 #include "part_actor.h"
 
+#include <cloud/blockstore/libs/diagnostics/block_digest.h>
 #include <cloud/blockstore/libs/diagnostics/critical_events.h>
 #include <cloud/blockstore/libs/storage/api/volume_proxy.h>
 #include <cloud/storage/core/libs/api/hive_proxy.h>
@@ -949,4 +950,40 @@ void SetCounters(
     counters.SetBlocksCount(blocksCount);
 }
 
+////////////////////////////////////////////////////////////////////////////////
+
+NProto::TError VerifyBlockChecksum(
+    const TBlockDataRef& block,
+    const NKikimr::TLogoBlobID& blobID,
+    const ui64 blockIndex,
+    const ui16 blobOffset,
+    const ui32 expectedChecksum)
+{
+    if (expectedChecksum == 0) {
+        // 0 is a special case - block digest calculation can be
+        // switched on and off => some blobs may not have digests for
+        // some blocks
+        //
+        // we should just skip validation for this block
+
+        return {};
+    }
+
+    const auto actualChecksum = ComputeDefaultDigest(block);
+
+    if (actualChecksum != expectedChecksum) {
+        ReportBlockDigestMismatchInBlob();
+        // we might read proper data upon retry - let's give it a chance
+        return MakeError(
+            E_REJECTED,
+            TStringBuilder() << "block digest mismatch, block="
+                << blockIndex << ", offset=" << blobOffset
+                << ", blobId=" << blobID
+                << ", expected=" << expectedChecksum
+                << ", actual=" << actualChecksum);
+    }
+
+    return {};
+}
+
 }   // namespace NCloud::NBlockStore::NStorage::NPartition

cloud/blockstore/libs/storage/partition/part_actor.h

@@ -27,6 +27,7 @@
 #include <cloud/blockstore/libs/storage/partition_common/long_running_operation_companion.h>
 
 #include <cloud/storage/core/libs/api/hive_proxy.h>
+#include <cloud/storage/core/libs/tablet/blob_id.h>
 #include <cloud/storage/core/libs/tablet/model/commit.h>
 
 #include <library/cpp/actors/core/actor.h>
@@ -644,4 +645,13 @@ void SetCounters(
     const TDuration waitTime,
     ui64 blocksCount);
 
+////////////////////////////////////////////////////////////////////////////////
+
+NProto::TError VerifyBlockChecksum(
+    const TBlockDataRef& block,
+    const NKikimr::TLogoBlobID& blobID,
+    const ui64 blockIndex,
+    const ui16 blobOffset,
+    const ui32 expectedChecksum);
+
 }   // namespace NCloud::NBlockStore::NStorage::NPartition

cloud/blockstore/libs/storage/partition/part_actor_addblobs.cpp

@@ -169,6 +169,10 @@ class TAddBlobsExecutor
             mixedBlocks.AddBlocks(blockIndex);
         }
 
+        for (ui32 checksum: blob.Checksums) {
+            blobMeta.AddBlockChecksums(checksum);
+        }
+
         db.WriteBlobMeta(blob.BlobId, blobMeta);
 
         if (!IsDeletionMarker(blob.BlobId)) {
@@ -226,6 +230,10 @@ class TAddBlobsExecutor
         mergedBlocks.SetEnd(blob.BlockRange.End);
         mergedBlocks.SetSkipped(skipped);
 
+        for (ui32 checksum: blob.Checksums) {
+            blobMeta.AddBlockChecksums(checksum);
+        }
+
         db.WriteBlobMeta(blob.BlobId, blobMeta);
 
         if (!IsDeletionMarker(blob.BlobId)) {
@@ -289,6 +297,10 @@ class TAddBlobsExecutor
             mixedBlocks.AddCommitIds(block.CommitId);
         }
 
+        for (ui32 checksum: blob.Checksums) {
+            blobMeta.AddBlockChecksums(checksum);
+        }
+
         db.WriteBlobMeta(blob.BlobId, blobMeta);
 
         if (!IsDeletionMarker(blob.BlobId)) {

cloud/blockstore/libs/storage/partition/part_actor_addconfirmedblobs.cpp

@@ -287,7 +287,8 @@ void TPartitionActor::HandleAddConfirmedBlobs(
             mergedBlobs.emplace_back(
                 MakePartialBlobId(commitId, blob.UniqueId),
                 blob.BlockRange,
-                TBlockMask());
+                TBlockMask(), // skipMask
+                TVector<ui32>() /* TODO: checksums */);
         }
 
         auto request = std::make_unique<TRequest>(