Fix corruption bug found and analyzed by dhruba@gmail.com

https://groups.google.com/d/msg/leveldb/Kc9JxuIUu5A/9P0N9RL4ar8J
This commit is contained in:
David Grogan 2013-01-07 13:17:43 -08:00 committed by Gavin Andresen
parent f79ddf24a9
commit 36311b9a19
5 changed files with 115 additions and 2 deletions

View file

@ -69,7 +69,7 @@ SHARED = $(SHARED1)
else
# Update db.h if you change these.
SHARED_MAJOR = 1
SHARED_MINOR = 8
SHARED_MINOR = 9
SHARED1 = libleveldb.$(PLATFORM_SHARED_EXT)
SHARED2 = $(SHARED1).$(SHARED_MAJOR)
SHARED3 = $(SHARED1).$(SHARED_MAJOR).$(SHARED_MINOR)

View file

@ -59,6 +59,12 @@ class SpecialEnv : public EnvWrapper {
// Simulate non-writable file system while this pointer is non-NULL
port::AtomicPointer non_writable_;
// Force sync of manifest files to fail while this pointer is non-NULL
port::AtomicPointer manifest_sync_error_;
// Force write to manifest files to fail while this pointer is non-NULL
port::AtomicPointer manifest_write_error_;
bool count_random_reads_;
AtomicCounter random_read_counter_;
@ -69,6 +75,8 @@ class SpecialEnv : public EnvWrapper {
no_space_.Release_Store(NULL);
non_writable_.Release_Store(NULL);
count_random_reads_ = false;
manifest_sync_error_.Release_Store(NULL);
manifest_write_error_.Release_Store(NULL);
}
Status NewWritableFile(const std::string& f, WritableFile** r) {
@ -100,6 +108,30 @@ class SpecialEnv : public EnvWrapper {
return base_->Sync();
}
};
class ManifestFile : public WritableFile {
private:
SpecialEnv* env_;
WritableFile* base_;
public:
ManifestFile(SpecialEnv* env, WritableFile* b) : env_(env), base_(b) { }
~ManifestFile() { delete base_; }
Status Append(const Slice& data) {
if (env_->manifest_write_error_.Acquire_Load() != NULL) {
return Status::IOError("simulated writer error");
} else {
return base_->Append(data);
}
}
Status Close() { return base_->Close(); }
Status Flush() { return base_->Flush(); }
Status Sync() {
if (env_->manifest_sync_error_.Acquire_Load() != NULL) {
return Status::IOError("simulated sync error");
} else {
return base_->Sync();
}
}
};
if (non_writable_.Acquire_Load() != NULL) {
return Status::IOError("simulated write error");
@ -109,6 +141,8 @@ class SpecialEnv : public EnvWrapper {
if (s.ok()) {
if (strstr(f.c_str(), ".sst") != NULL) {
*r = new SSTableFile(this, *r);
} else if (strstr(f.c_str(), "MANIFEST") != NULL) {
*r = new ManifestFile(this, *r);
}
}
return s;
@ -1492,6 +1526,47 @@ TEST(DBTest, NonWritableFileSystem) {
env_->non_writable_.Release_Store(NULL);
}
TEST(DBTest, ManifestWriteError) {
// Test for the following problem:
// (a) Compaction produces file F
// (b) Log record containing F is written to MANIFEST file, but Sync() fails
// (c) GC deletes F
// (d) After reopening DB, reads fail since deleted F is named in log record
// We iterate twice. In the second iteration, everything is the
// same except the log record never makes it to the MANIFEST file.
for (int iter = 0; iter < 2; iter++) {
port::AtomicPointer* error_type = (iter == 0)
? &env_->manifest_sync_error_
: &env_->manifest_write_error_;
// Insert foo=>bar mapping
Options options = CurrentOptions();
options.env = env_;
options.create_if_missing = true;
options.error_if_exists = false;
DestroyAndReopen(&options);
ASSERT_OK(Put("foo", "bar"));
ASSERT_EQ("bar", Get("foo"));
// Memtable compaction (will succeed)
dbfull()->TEST_CompactMemTable();
ASSERT_EQ("bar", Get("foo"));
const int last = config::kMaxMemCompactLevel;
ASSERT_EQ(NumTableFilesAtLevel(last), 1); // foo=>bar is now in last level
// Merging compaction (will fail)
error_type->Release_Store(env_);
dbfull()->TEST_CompactRange(last, NULL, NULL); // Should fail
ASSERT_EQ("bar", Get("foo"));
// Recovery: should not lose data
error_type->Release_Store(NULL);
Reopen(&options);
ASSERT_EQ("bar", Get("foo"));
}
}
TEST(DBTest, FilesDeletedAfterCompaction) {
ASSERT_OK(Put("foo", "v2"));
Compact("a", "z");

View file

@ -786,12 +786,23 @@ Status VersionSet::LogAndApply(VersionEdit* edit, port::Mutex* mu) {
if (s.ok()) {
s = descriptor_file_->Sync();
}
if (!s.ok()) {
Log(options_->info_log, "MANIFEST write: %s\n", s.ToString().c_str());
if (ManifestContains(record)) {
Log(options_->info_log,
"MANIFEST contains log record despite error; advancing to new "
"version to prevent mismatch between in-memory and logged state");
s = Status::OK();
}
}
}
// If we just created a new descriptor file, install it by writing a
// new CURRENT file that points to it.
if (s.ok() && !new_manifest_file.empty()) {
s = SetCurrentFile(env_, dbname_, manifest_file_number_);
// No need to double-check MANIFEST in case of error since it
// will be discarded below.
}
mu->Lock();
@ -1025,6 +1036,31 @@ const char* VersionSet::LevelSummary(LevelSummaryStorage* scratch) const {
return scratch->buffer;
}
// Return true iff the manifest contains the specified record.
bool VersionSet::ManifestContains(const std::string& record) const {
std::string fname = DescriptorFileName(dbname_, manifest_file_number_);
Log(options_->info_log, "ManifestContains: checking %s\n", fname.c_str());
SequentialFile* file = NULL;
Status s = env_->NewSequentialFile(fname, &file);
if (!s.ok()) {
Log(options_->info_log, "ManifestContains: %s\n", s.ToString().c_str());
return false;
}
log::Reader reader(file, NULL, true/*checksum*/, 0);
Slice r;
std::string scratch;
bool result = false;
while (reader.ReadRecord(&r, &scratch)) {
if (r == Slice(record)) {
result = true;
break;
}
}
delete file;
Log(options_->info_log, "ManifestContains: result = %d\n", result ? 1 : 0);
return result;
}
uint64_t VersionSet::ApproximateOffsetOf(Version* v, const InternalKey& ikey) {
uint64_t result = 0;
for (int level = 0; level < config::kNumLevels; level++) {

View file

@ -277,6 +277,8 @@ class VersionSet {
void AppendVersion(Version* v);
bool ManifestContains(const std::string& record) const;
Env* const env_;
const std::string dbname_;
const Options* const options_;

View file

@ -14,7 +14,7 @@ namespace leveldb {
// Update Makefile if you change these
static const int kMajorVersion = 1;
static const int kMinorVersion = 8;
static const int kMinorVersion = 9;
struct Options;
struct ReadOptions;