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Atomic flush rollback once on failure (#6385)

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Summary:
Before this fix, atomic flush codepath may hit an assertion failure on a specific failure case.
If all flush jobs within an atomic flush succeed (they do not write to MANIFEST), but batch writing version edits to MANIFEST fails, then `cfd->imm()->RollbackMemTableFlush()` will be called twice, and the second invocation hits assertion failure `assert(m->flush_in_progress_)` since the first invocation resets the variable `flush_in_progress_` to false already.

Test plan (dev server):
```
./db_flush_test --gtest_filter=DBAtomicFlushTest/DBAtomicFlushTest.RollbackAfterFailToInstallResults
make check
```
Both must succeed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6385

Differential Revision: D19782943

Pulled By: riversand963

fbshipit-source-id: 84e1592625e729d1b70fdc8479959387a74cb121
This commit is contained in:
Yanqin Jin 2020-02-07 10:50:17 -08:00 committed by Facebook Github Bot
parent c6f75516b7
commit f361cedf06
2 changed files with 48 additions and 18 deletions
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29
db/db_flush_test.cc
View File

@ -741,6 +741,35 @@ TEST_P(DBAtomicFlushTest, CFDropRaceWithWaitForFlushMemTables) {
SyncPoint::GetInstance()->DisableProcessing();
}
TEST_P(DBAtomicFlushTest, RollbackAfterFailToInstallResults) {
bool atomic_flush = GetParam();
if (!atomic_flush) {
return;
}
auto fault_injection_env = std::make_shared<FaultInjectionTestEnv>(env_);
Options options = CurrentOptions();
options.env = fault_injection_env.get();
options.create_if_missing = true;
options.atomic_flush = atomic_flush;
CreateAndReopenWithCF({"pikachu"}, options);
ASSERT_EQ(2, handles_.size());
for (size_t cf = 0; cf < handles_.size(); ++cf) {
ASSERT_OK(Put(static_cast<int>(cf), "a", "value"));
}
SyncPoint::GetInstance()->DisableProcessing();
SyncPoint::GetInstance()->ClearAllCallBacks();
SyncPoint::GetInstance()->SetCallBack(
"VersionSet::ProcessManifestWrites:BeforeWriteLastVersionEdit:0",
[&](void* /*arg*/) { fault_injection_env->SetFilesystemActive(false); });
SyncPoint::GetInstance()->EnableProcessing();
FlushOptions flush_opts;
Status s = db_->Flush(flush_opts, handles_);
ASSERT_NOK(s);
fault_injection_env->SetFilesystemActive(true);
Close();
SyncPoint::GetInstance()->ClearAllCallBacks();
}
INSTANTIATE_TEST_CASE_P(DBFlushDirectIOTest, DBFlushDirectIOTest,
testing::Bool());

37
db/db_impl/db_impl_compaction_flush.cc
View File

@ -409,7 +409,7 @@ Status DBImpl::AtomicFlushMemTablesToOutputFiles(
s = Status::OK();
}
if (s.ok() || s.IsShutdownInProgress() || s.IsColumnFamilyDropped()) {
if (s.ok() || s.IsShutdownInProgress()) {
// Sync on all distinct output directories.
for (auto dir : distinct_output_dirs) {
if (dir != nullptr) {
@ -420,6 +420,23 @@ Status DBImpl::AtomicFlushMemTablesToOutputFiles(
}
}
}
} else {
// Need to undo atomic flush if something went wrong, i.e. s is not OK and
// it is not because of CF drop.
// Have to cancel the flush jobs that have NOT executed because we need to
// unref the versions.
for (int i = 0; i != num_cfs; ++i) {
if (!exec_status[i].first) {
jobs[i]->Cancel();
}
}
for (int i = 0; i != num_cfs; ++i) {
if (exec_status[i].first && exec_status[i].second.ok()) {
auto& mems = jobs[i]->GetMemTables();
cfds[i]->imm()->RollbackMemtableFlush(mems,
file_meta[i].fd.GetNumber());
}
}
}
if (s.ok()) {
@ -526,23 +543,7 @@ Status DBImpl::AtomicFlushMemTablesToOutputFiles(
#endif // ROCKSDB_LITE
}
// Need to undo atomic flush if something went wrong, i.e. s is not OK and
// it is not because of CF drop.
if (!s.ok() && !s.IsColumnFamilyDropped()) {
// Have to cancel the flush jobs that have NOT executed because we need to
// unref the versions.
for (int i = 0; i != num_cfs; ++i) {
if (!exec_status[i].first) {
jobs[i]->Cancel();
}
}
for (int i = 0; i != num_cfs; ++i) {
if (exec_status[i].first && exec_status[i].second.ok()) {
auto& mems = jobs[i]->GetMemTables();
cfds[i]->imm()->RollbackMemtableFlush(mems,
file_meta[i].fd.GetNumber());
}
}
if (!s.ok() && !s.IsShutdownInProgress()) {
Status new_bg_error = s;
error_handler_.SetBGError(new_bg_error, BackgroundErrorReason::kFlush);
}