Fix a bug in WAL tracking (facebook#10087)

Summary:
Closing facebook#10080

When `SyncWAL()` calls `MarkLogsSynced()`, even if there is only one active WAL file,
this event should still be added to the MANIFEST.

Pull Request resolved: facebook#10087

Test Plan: make check

Reviewed By: ajkr

Differential Revision: D36797580

Pulled By: riversand963

fbshipit-source-id: 24184c9dd606b3939a454ed41de6e868d1519999

HISTORY.md

@@ -1,4 +1,8 @@
 # Rocksdb Change Log
+## 7.3.1 (06/08/2022)
+### Bug Fixes
+* Fix a bug in WAL tracking. Before this PR (#10087), calling `SyncWAL()` on the only WAL file of the db will not log the event in MANIFEST, thus allowing a subsequent `DB::Open` even if the WAL file is missing or corrupted.
+
 ## 7.3.0 (05/20/2022)
 ### Bug Fixes
 * Fixed a bug where manual flush would block forever even though flush options had wait=false.

db/db_basic_test.cc

@@ -4096,6 +4096,27 @@ TEST_F(DBBasicTest, VerifyFileChecksums) {
   Reopen(options);
   ASSERT_TRUE(db_->VerifyFileChecksums(ReadOptions()).IsInvalidArgument());
 }
+
+TEST_F(DBBasicTest, ManualWalSync) {
+  Options options = CurrentOptions();
+  options.track_and_verify_wals_in_manifest = true;
+  options.wal_recovery_mode = WALRecoveryMode::kAbsoluteConsistency;
+  DestroyAndReopen(options);
+
+  ASSERT_OK(Put("x", "y"));
+  // This does not create a new WAL.
+  ASSERT_OK(db_->SyncWAL());
+  EXPECT_FALSE(dbfull()->GetVersionSet()->GetWalSet().GetWals().empty());
+
+  std::unique_ptr<LogFile> wal;
+  Status s = db_->GetCurrentWalFile(&wal);
+  ASSERT_OK(s);
+  Close();
+
+  EXPECT_OK(env_->DeleteFile(LogFileName(dbname_, wal->LogNumber())));
+
+  ASSERT_TRUE(TryReopen(options).IsCorruption());
+}
 #endif  // !ROCKSDB_LITE
 
 // A test class for intercepting random reads and injecting artificial

db/db_impl/db_impl.cc

@@ -1441,12 +1441,13 @@ Status DBImpl::MarkLogsSynced(uint64_t up_to, bool synced_dir) {
   for (auto it = logs_.begin(); it != logs_.end() && it->number <= up_to;) {
     auto& wal = *it;
     assert(wal.getting_synced);
+    if (immutable_db_options_.track_and_verify_wals_in_manifest &&
+        wal.writer->file()->GetFileSize() > 0) {
+      synced_wals.AddWal(wal.number,
+                         WalMetadata(wal.writer->file()->GetFileSize()));
+    }
+
     if (logs_.size() > 1) {
-      if (immutable_db_options_.track_and_verify_wals_in_manifest &&
-          wal.writer->file()->GetFileSize() > 0) {
-        synced_wals.AddWal(wal.number,
-                           WalMetadata(wal.writer->file()->GetFileSize()));
-      }
       logs_to_free_.push_back(wal.ReleaseWriter());
       // To modify logs_ both mutex_ and log_write_mutex_ must be held
       InstrumentedMutexLock l(&log_write_mutex_);

file/writable_file_writer.cc

@@ -163,7 +163,8 @@ IOStatus WritableFileWriter::Append(const Slice& data, uint32_t crc32c_checksum,
 
   TEST_KILL_RANDOM("WritableFileWriter::Append:1");
   if (s.ok()) {
-    filesize_ += data.size();
+    uint64_t cur_size = filesize_.load(std::memory_order_acquire);
+    filesize_.store(cur_size + data.size(), std::memory_order_release);
   }
   return s;
 }
@@ -191,7 +192,8 @@ IOStatus WritableFileWriter::Pad(const size_t pad_bytes,
     cap = buf_.Capacity() - buf_.CurrentSize();
   }
   pending_sync_ = true;
-  filesize_ += pad_bytes;
+  uint64_t cur_size = filesize_.load(std::memory_order_acquire);
+  filesize_.store(cur_size + pad_bytes, std::memory_order_release);
   if (perform_data_verification_) {
     buffered_data_crc32c_checksum_ =
         crc32c::Extend(buffered_data_crc32c_checksum_,
@@ -227,14 +229,15 @@ IOStatus WritableFileWriter::Close() {
         start_ts = FileOperationInfo::StartNow();
       }
 #endif
-      interim = writable_file_->Truncate(filesize_, io_options, nullptr);
+      uint64_t filesz = filesize_.load(std::memory_order_acquire);
+      interim = writable_file_->Truncate(filesz, io_options, nullptr);
 #ifndef ROCKSDB_LITE
       if (ShouldNotifyListeners()) {
         auto finish_ts = FileOperationInfo::FinishNow();
         NotifyOnFileTruncateFinish(start_ts, finish_ts, s);
         if (!interim.ok()) {
           NotifyOnIOError(interim, FileOperationType::kTruncate, file_name(),
-                          filesize_);
+                          filesz);
         }
       }
 #endif
@@ -372,8 +375,9 @@ IOStatus WritableFileWriter::Flush(Env::IOPriority op_rate_limiter_priority) {
     const uint64_t kBytesNotSyncRange =
         1024 * 1024;                                // recent 1MB is not synced.
     const uint64_t kBytesAlignWhenSync = 4 * 1024;  // Align 4KB.
-    if (filesize_ > kBytesNotSyncRange) {
-      uint64_t offset_sync_to = filesize_ - kBytesNotSyncRange;
+    uint64_t cur_size = filesize_.load(std::memory_order_acquire);
+    if (cur_size > kBytesNotSyncRange) {
+      uint64_t offset_sync_to = cur_size - kBytesNotSyncRange;
       offset_sync_to -= offset_sync_to % kBytesAlignWhenSync;
       assert(offset_sync_to >= last_sync_size_);
       if (offset_sync_to > 0 &&

file/writable_file_writer.h

@@ -142,7 +142,7 @@ class WritableFileWriter {
   size_t max_buffer_size_;
   // Actually written data size can be used for truncate
   // not counting padding data
-  uint64_t filesize_;
+  std::atomic<uint64_t> filesize_;
 #ifndef ROCKSDB_LITE
   // This is necessary when we use unbuffered access
   // and writes must happen on aligned offsets
@@ -255,7 +255,9 @@ class WritableFileWriter {
   // returns NotSupported status.
   IOStatus SyncWithoutFlush(bool use_fsync);
 
-  uint64_t GetFileSize() const { return filesize_; }
+  uint64_t GetFileSize() const {
+    return filesize_.load(std::memory_order_acquire);
+  }
 
   IOStatus InvalidateCache(size_t offset, size_t length) {
     return writable_file_->InvalidateCache(offset, length);