@ -36,7 +36,8 @@ Status WritableFileWriter::Create(const std::shared_ptr<FileSystem>& fs,
return s ;
}
IOStatus WritableFileWriter : : Append ( const Slice & data ) {
IOStatus WritableFileWriter : : Append ( const Slice & data ,
uint32_t crc32c_checksum ) {
const char * src = data . data ( ) ;
size_t left = data . size ( ) ;
IOStatus s ;
@ -81,26 +82,74 @@ IOStatus WritableFileWriter::Append(const Slice& data) {
assert ( buf_ . CurrentSize ( ) = = 0 ) ;
}
// We never write directly to disk with direct I/O on.
// or we simply use it for its original purpose to accumulate many small
// chunks
if ( use_direct_io ( ) | | ( buf_ . Capacity ( ) > = left ) ) {
while ( left > 0 ) {
size_t appended = buf_ . Append ( src , left ) ;
left - = appended ;
src + = appended ;
if ( left > 0 ) {
s = Flush ( ) ;
if ( ! s . ok ( ) ) {
break ;
if ( perform_data_verification_ & & buffered_data_with_checksum_ & &
crc32c_checksum ! = 0 ) {
// Since we want to use the checksum of the input data, we cannot break it
// into several pieces. We will only write them in the buffer when buffer
// size is enough. Otherwise, we will directly write it down.
if ( use_direct_io ( ) | | ( buf_ . Capacity ( ) - buf_ . CurrentSize ( ) ) > = left ) {
if ( ( buf_ . Capacity ( ) - buf_ . CurrentSize ( ) ) > = left ) {
size_t appended = buf_ . Append ( src , left ) ;
if ( appended ! = left ) {
s = IOStatus : : Corruption ( " Write buffer append failure " ) ;
}
buffered_data_crc32c_checksum_ = crc32c : : Crc32cCombine (
buffered_data_crc32c_checksum_ , crc32c_checksum , appended ) ;
} else {
while ( left > 0 ) {
size_t appended = buf_ . Append ( src , left ) ;
buffered_data_crc32c_checksum_ =
crc32c : : Extend ( buffered_data_crc32c_checksum_ , src , appended ) ;
left - = appended ;
src + = appended ;
if ( left > 0 ) {
s = Flush ( ) ;
if ( ! s . ok ( ) ) {
break ;
}
}
}
}
} else {
assert ( buf_ . CurrentSize ( ) = = 0 ) ;
buffered_data_crc32c_checksum_ = crc32c_checksum ;
s = WriteBufferedWithChecksum ( src , left ) ;
}
} else {
// Writing directly to file bypassing the buffer
assert ( buf_ . CurrentSize ( ) = = 0 ) ;
s = WriteBuffered ( src , left ) ;
// In this case, either we do not need to do the data verification or
// caller does not provide the checksum of the data (crc32c_checksum = 0).
//
// We never write directly to disk with direct I/O on.
// or we simply use it for its original purpose to accumulate many small
// chunks
if ( use_direct_io ( ) | | ( buf_ . Capacity ( ) > = left ) ) {
while ( left > 0 ) {
size_t appended = buf_ . Append ( src , left ) ;
if ( perform_data_verification_ & & buffered_data_with_checksum_ ) {
buffered_data_crc32c_checksum_ =
crc32c : : Extend ( buffered_data_crc32c_checksum_ , src , appended ) ;
}
left - = appended ;
src + = appended ;
if ( left > 0 ) {
s = Flush ( ) ;
if ( ! s . ok ( ) ) {
break ;
}
}
}
} else {
// Writing directly to file bypassing the buffer
assert ( buf_ . CurrentSize ( ) = = 0 ) ;
if ( perform_data_verification_ & & buffered_data_with_checksum_ ) {
buffered_data_crc32c_checksum_ = crc32c : : Value ( src , left ) ;
s = WriteBufferedWithChecksum ( src , left ) ;
} else {
s = WriteBuffered ( src , left ) ;
}
}
}
TEST_KILL_RANDOM ( " WritableFileWriter::Append:1 " ) ;
@ -114,6 +163,7 @@ IOStatus WritableFileWriter::Pad(const size_t pad_bytes) {
assert ( pad_bytes < kDefaultPageSize ) ;
size_t left = pad_bytes ;
size_t cap = buf_ . Capacity ( ) - buf_ . CurrentSize ( ) ;
size_t pad_start = buf_ . CurrentSize ( ) ;
// Assume pad_bytes is small compared to buf_ capacity. So we always
// use buf_ rather than write directly to file in certain cases like
@ -132,6 +182,11 @@ IOStatus WritableFileWriter::Pad(const size_t pad_bytes) {
}
pending_sync_ = true ;
filesize_ + = pad_bytes ;
if ( perform_data_verification_ ) {
buffered_data_crc32c_checksum_ =
crc32c : : Extend ( buffered_data_crc32c_checksum_ ,
buf_ . BufferStart ( ) + pad_start , pad_bytes ) ;
}
return IOStatus : : OK ( ) ;
}
@ -232,11 +287,19 @@ IOStatus WritableFileWriter::Flush() {
if ( use_direct_io ( ) ) {
# ifndef ROCKSDB_LITE
if ( pending_sync_ ) {
s = WriteDirect ( ) ;
if ( perform_data_verification_ & & buffered_data_with_checksum_ ) {
s = WriteDirectWithChecksum ( ) ;
} else {
s = WriteDirect ( ) ;
}
}
# endif // !ROCKSDB_LITE
} else {
s = WriteBuffered ( buf_ . BufferStart ( ) , buf_ . CurrentSize ( ) ) ;
if ( perform_data_verification_ & & buffered_data_with_checksum_ ) {
s = WriteBufferedWithChecksum ( buf_ . BufferStart ( ) , buf_ . CurrentSize ( ) ) ;
} else {
s = WriteBuffered ( buf_ . BufferStart ( ) , buf_ . CurrentSize ( ) ) ;
}
}
if ( ! s . ok ( ) ) {
return s ;
@ -451,6 +514,76 @@ IOStatus WritableFileWriter::WriteBuffered(const char* data, size_t size) {
src + = allowed ;
}
buf_ . Size ( 0 ) ;
buffered_data_crc32c_checksum_ = 0 ;
return s ;
}
IOStatus WritableFileWriter : : WriteBufferedWithChecksum ( const char * data ,
size_t size ) {
IOStatus s ;
assert ( ! use_direct_io ( ) ) ;
assert ( perform_data_verification_ & & buffered_data_with_checksum_ ) ;
const char * src = data ;
size_t left = size ;
DataVerificationInfo v_info ;
char checksum_buf [ sizeof ( uint32_t ) ] ;
// Check how much is allowed. Here, we loop until the rate limiter allows to
// write the entire buffer.
// TODO: need to be improved since it sort of defeats the purpose of the rate
// limiter
size_t data_size = left ;
if ( rate_limiter_ ! = nullptr ) {
while ( data_size > 0 ) {
size_t tmp_size ;
tmp_size = rate_limiter_ - > RequestToken (
data_size , buf_ . Alignment ( ) , writable_file_ - > GetIOPriority ( ) , stats_ ,
RateLimiter : : OpType : : kWrite ) ;
data_size - = tmp_size ;
}
}
{
IOSTATS_TIMER_GUARD ( write_nanos ) ;
TEST_SYNC_POINT ( " WritableFileWriter::Flush:BeforeAppend " ) ;
# ifndef ROCKSDB_LITE
FileOperationInfo : : StartTimePoint start_ts ;
uint64_t old_size = writable_file_ - > GetFileSize ( IOOptions ( ) , nullptr ) ;
if ( ShouldNotifyListeners ( ) ) {
start_ts = FileOperationInfo : : StartNow ( ) ;
old_size = next_write_offset_ ;
}
# endif
{
auto prev_perf_level = GetPerfLevel ( ) ;
IOSTATS_CPU_TIMER_GUARD ( cpu_write_nanos , clock_ ) ;
EncodeFixed32 ( checksum_buf , buffered_data_crc32c_checksum_ ) ;
v_info . checksum = Slice ( checksum_buf , sizeof ( uint32_t ) ) ;
s = writable_file_ - > Append ( Slice ( src , left ) , IOOptions ( ) , v_info ,
nullptr ) ;
SetPerfLevel ( prev_perf_level ) ;
}
# ifndef ROCKSDB_LITE
if ( ShouldNotifyListeners ( ) ) {
auto finish_ts = std : : chrono : : steady_clock : : now ( ) ;
NotifyOnFileWriteFinish ( old_size , left , start_ts , finish_ts , s ) ;
}
# endif
if ( ! s . ok ( ) ) {
return s ;
}
}
IOSTATS_ADD ( bytes_written , left ) ;
TEST_KILL_RANDOM ( " WritableFileWriter::WriteBuffered:0 " ) ;
// Buffer write is successful, reset the buffer current size to 0 and reset
// the corresponding checksum value
buf_ . Size ( 0 ) ;
buffered_data_crc32c_checksum_ = 0 ;
return s ;
}
@ -565,5 +698,99 @@ IOStatus WritableFileWriter::WriteDirect() {
}
return s ;
}
IOStatus WritableFileWriter : : WriteDirectWithChecksum ( ) {
assert ( use_direct_io ( ) ) ;
assert ( perform_data_verification_ & & buffered_data_with_checksum_ ) ;
IOStatus s ;
const size_t alignment = buf_ . Alignment ( ) ;
assert ( ( next_write_offset_ % alignment ) = = 0 ) ;
// Calculate whole page final file advance if all writes succeed
size_t file_advance = TruncateToPageBoundary ( alignment , buf_ . CurrentSize ( ) ) ;
// Calculate the leftover tail, we write it here padded with zeros BUT we
// will write
// it again in the future either on Close() OR when the current whole page
// fills out
size_t leftover_tail = buf_ . CurrentSize ( ) - file_advance ;
// Round up, pad, and combine the checksum.
size_t last_cur_size = buf_ . CurrentSize ( ) ;
buf_ . PadToAlignmentWith ( 0 ) ;
size_t padded_size = buf_ . CurrentSize ( ) - last_cur_size ;
const char * padded_start = buf_ . BufferStart ( ) + last_cur_size ;
uint32_t padded_checksum = crc32c : : Value ( padded_start , padded_size ) ;
buffered_data_crc32c_checksum_ = crc32c : : Crc32cCombine (
buffered_data_crc32c_checksum_ , padded_checksum , padded_size ) ;
const char * src = buf_ . BufferStart ( ) ;
uint64_t write_offset = next_write_offset_ ;
size_t left = buf_ . CurrentSize ( ) ;
DataVerificationInfo v_info ;
char checksum_buf [ sizeof ( uint32_t ) ] ;
// Check how much is allowed. Here, we loop until the rate limiter allows to
// write the entire buffer.
// TODO: need to be improved since it sort of defeats the purpose of the rate
// limiter
size_t data_size = left ;
if ( rate_limiter_ ! = nullptr ) {
while ( data_size > 0 ) {
size_t size ;
size = rate_limiter_ - > RequestToken ( data_size , buf_ . Alignment ( ) ,
writable_file_ - > GetIOPriority ( ) ,
stats_ , RateLimiter : : OpType : : kWrite ) ;
data_size - = size ;
}
}
{
IOSTATS_TIMER_GUARD ( write_nanos ) ;
TEST_SYNC_POINT ( " WritableFileWriter::Flush:BeforeAppend " ) ;
FileOperationInfo : : StartTimePoint start_ts ;
if ( ShouldNotifyListeners ( ) ) {
start_ts = FileOperationInfo : : StartNow ( ) ;
}
// direct writes must be positional
EncodeFixed32 ( checksum_buf , buffered_data_crc32c_checksum_ ) ;
v_info . checksum = Slice ( checksum_buf , sizeof ( uint32_t ) ) ;
s = writable_file_ - > PositionedAppend ( Slice ( src , left ) , write_offset ,
IOOptions ( ) , v_info , nullptr ) ;
if ( ShouldNotifyListeners ( ) ) {
auto finish_ts = std : : chrono : : steady_clock : : now ( ) ;
NotifyOnFileWriteFinish ( write_offset , left , start_ts , finish_ts , s ) ;
}
if ( ! s . ok ( ) ) {
// In this case, we do not change buffered_data_crc32c_checksum_ because
// it still aligns with the data in the buffer.
buf_ . Size ( file_advance + leftover_tail ) ;
buffered_data_crc32c_checksum_ =
crc32c : : Value ( buf_ . BufferStart ( ) , buf_ . CurrentSize ( ) ) ;
return s ;
}
}
IOSTATS_ADD ( bytes_written , left ) ;
assert ( ( next_write_offset_ % alignment ) = = 0 ) ;
if ( s . ok ( ) ) {
// Move the tail to the beginning of the buffer
// This never happens during normal Append but rather during
// explicit call to Flush()/Sync() or Close(). Also the buffer checksum will
// recalculated accordingly.
buf_ . RefitTail ( file_advance , leftover_tail ) ;
// Adjust the checksum value to align with the data in the buffer
buffered_data_crc32c_checksum_ =
crc32c : : Value ( buf_ . BufferStart ( ) , buf_ . CurrentSize ( ) ) ;
// This is where we start writing next time which may or not be
// the actual file size on disk. They match if the buffer size
// is a multiple of whole pages otherwise filesize_ is leftover_tail
// behind
next_write_offset_ + = file_advance ;
}
return s ;
}
# endif // !ROCKSDB_LITE
} // namespace ROCKSDB_NAMESPACE
Zhichao Cao
3 years ago
committed by