leveldb: Fix PosixWritableFile::Sync() on Apple systems.
Apple doesn't follow POSIX specifications for fsync(). Instead, fsync() guarantees to flush the buffer cache to the device, which means the data will survive kernel panics, but may not survive power outages. Applications that need stronger guarantees (like databases) need to use fcntl(F_FULLFSYNC).
This CL switches PosixWritableFile::Sync() to get the stronger guarantees on Apple systems. The improved implementation follows the same principles as SQLite [1] and node.js [2].
Research for the fcntl() to fsync() fallback strategy:
Apple's released source code at https://opensource.apple.com/ shows at least three different error codes being returned when a filesystem does not support F_FULLFSYNC.
fcntl() is implemented in xnu-4903.221.2 in bsd/kern/kern_descrip.c, where it delegates to fcntl_nocancel(). The documentation for fcntl_nocancel() mentions error codes for some operations, but does not include F_FULLFSYNC. The F_FULLSYNC branch in fcntl_nocancel() calls VNOP_IOCTL(_, F_FULLSYNC, NULL, 0, _), whose return value sets the error
code.
VNOP_IOCTL() is implemented in bsd/vfs/kpi_vfs.c and calls the ioctl function in the vnode's operation vector. The per-filesystem function names follow the pattern _vnop_ioctl() for all the instances in opensource code: {hfs,msdosfs,nfs,ntfs,smbfs,webdav,zfs}_vnop_ioctl().
hfs-407.30.1, msdosfs-229.200.3, and nfs in xnu-4903.221.2 handle F_FULLFSYNC. ntfs-94.200.1 and smb-759.40.1 do not handle F_FULLFSYNC, and the default branch returns ENOSUP. webdav-380.200.1 also does not handle F_FULLFSYNC, but the default branch returns EINVAL. zfs-59 also does not handle F_FULLSYNC, and its default branch returns ENOTTY.
From a different angle, Apple's ntfs-94.200.1 includes utility code that uses fcntl(F_FULLFSYNC) and falls back to fsync() just like we do, supporting the hypothesis that there is no good way to detect lack of F_FULLFSYNC support. Also, Apple's fcntl() man page [3] does not mention a way to detect lack of F_FULLFSYNC support.
[1] https://www.sqlite.org/src/doc/trunk/src/os_unix.c
[2] https://github.com/libuv/libuv/blob/master/src/unix/fs.c
[3] https://developer.apple.com/library/archive/documentatiVon/System/Conceptual/ManPages_iPhoneOS/man2/fcntl.2.html
Tested:
https://travis-ci.org/pwnall/leveldb/builds/477318498
TAP global presubmit
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=228593729
5 år sedan |
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- # Copyright 2017 The LevelDB Authors. All rights reserved.
- # Use of this source code is governed by a BSD-style license that can be
- # found in the LICENSE file. See the AUTHORS file for names of contributors.
-
- cmake_minimum_required(VERSION 3.9)
- # Keep the version below in sync with the one in db.h
- project(leveldb VERSION 1.23.0 LANGUAGES C CXX)
-
- # C standard can be overridden when this is used as a sub-project.
- if(NOT CMAKE_C_STANDARD)
- # This project can use C11, but will gracefully decay down to C89.
- set(CMAKE_C_STANDARD 11)
- set(CMAKE_C_STANDARD_REQUIRED OFF)
- set(CMAKE_C_EXTENSIONS OFF)
- endif(NOT CMAKE_C_STANDARD)
-
- # C++ standard can be overridden when this is used as a sub-project.
- if(NOT CMAKE_CXX_STANDARD)
- # This project requires C++11.
- set(CMAKE_CXX_STANDARD 11)
- set(CMAKE_CXX_STANDARD_REQUIRED ON)
- set(CMAKE_CXX_EXTENSIONS OFF)
- endif(NOT CMAKE_CXX_STANDARD)
-
- if (WIN32)
- set(LEVELDB_PLATFORM_NAME LEVELDB_PLATFORM_WINDOWS)
- # TODO(cmumford): Make UNICODE configurable for Windows.
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- else (WIN32)
- set(LEVELDB_PLATFORM_NAME LEVELDB_PLATFORM_POSIX)
- endif (WIN32)
-
- option(LEVELDB_BUILD_TESTS "Build LevelDB's unit tests" ON)
- option(LEVELDB_BUILD_BENCHMARKS "Build LevelDB's benchmarks" ON)
- option(LEVELDB_INSTALL "Install LevelDB's header and library" ON)
-
- include(CheckIncludeFile)
- check_include_file("unistd.h" HAVE_UNISTD_H)
-
- include(CheckLibraryExists)
- check_library_exists(crc32c crc32c_value "" HAVE_CRC32C)
- check_library_exists(snappy snappy_compress "" HAVE_SNAPPY)
- check_library_exists(tcmalloc malloc "" HAVE_TCMALLOC)
-
- include(CheckCXXSymbolExists)
- # Using check_cxx_symbol_exists() instead of check_c_symbol_exists() because
- # we're including the header from C++, and feature detection should use the same
- # compiler language that the project will use later. Principles aside, some
- # versions of do not expose fdatasync() in <unistd.h> in standard C mode
- # (-std=c11), but do expose the function in standard C++ mode (-std=c++11).
- check_cxx_symbol_exists(fdatasync "unistd.h" HAVE_FDATASYNC)
- check_cxx_symbol_exists(F_FULLFSYNC "fcntl.h" HAVE_FULLFSYNC)
- check_cxx_symbol_exists(O_CLOEXEC "fcntl.h" HAVE_O_CLOEXEC)
-
- if(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
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- endif(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
-
- # Test whether -Wthread-safety is available. See
- # https://clang.llvm.org/docs/ThreadSafetyAnalysis.html
- include(CheckCXXCompilerFlag)
- check_cxx_compiler_flag(-Wthread-safety HAVE_CLANG_THREAD_SAFETY)
-
- # Used by googletest.
- check_cxx_compiler_flag(-Wno-missing-field-initializers
- LEVELDB_HAVE_NO_MISSING_FIELD_INITIALIZERS)
-
- include(CheckCXXSourceCompiles)
-
- # Test whether C++17 __has_include is available.
- check_cxx_source_compiles("
- #if defined(__has_include) && __has_include(<string>)
- #include <string>
- #endif
- int main() { std::string str; return 0; }
- " HAVE_CXX17_HAS_INCLUDE)
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- set(LEVELDB_PUBLIC_INCLUDE_DIR "include/leveldb")
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- configure_file(
- "port/port_config.h.in"
- "${PROJECT_BINARY_DIR}/${LEVELDB_PORT_CONFIG_DIR}/port_config.h"
- )
-
- include_directories(
- "${PROJECT_BINARY_DIR}/include"
- "."
- )
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- if(BUILD_SHARED_LIBS)
- # Only export LEVELDB_EXPORT symbols from the shared library.
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- # Must be included before CMAKE_INSTALL_INCLUDEDIR is used.
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- add_library(leveldb "")
- target_sources(leveldb
- PRIVATE
- "${PROJECT_BINARY_DIR}/${LEVELDB_PORT_CONFIG_DIR}/port_config.h"
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- "db/builder.h"
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- "db/db_impl.cc"
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- "db/db_iter.h"
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- "util/crc32c.h"
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-
- # Only CMake 3.3+ supports PUBLIC sources in targets exported by "install".
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- "${LEVELDB_PUBLIC_INCLUDE_DIR}/c.h"
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- "${LEVELDB_PUBLIC_INCLUDE_DIR}/comparator.h"
- "${LEVELDB_PUBLIC_INCLUDE_DIR}/db.h"
- "${LEVELDB_PUBLIC_INCLUDE_DIR}/dumpfile.h"
- "${LEVELDB_PUBLIC_INCLUDE_DIR}/env.h"
- "${LEVELDB_PUBLIC_INCLUDE_DIR}/export.h"
- "${LEVELDB_PUBLIC_INCLUDE_DIR}/filter_policy.h"
- "${LEVELDB_PUBLIC_INCLUDE_DIR}/iterator.h"
- "${LEVELDB_PUBLIC_INCLUDE_DIR}/options.h"
- "${LEVELDB_PUBLIC_INCLUDE_DIR}/slice.h"
- "${LEVELDB_PUBLIC_INCLUDE_DIR}/status.h"
- "${LEVELDB_PUBLIC_INCLUDE_DIR}/table_builder.h"
- "${LEVELDB_PUBLIC_INCLUDE_DIR}/table.h"
- "${LEVELDB_PUBLIC_INCLUDE_DIR}/write_batch.h"
- )
-
- if (WIN32)
- target_sources(leveldb
- PRIVATE
- "util/env_windows.cc"
- "util/windows_logger.h"
- )
- else (WIN32)
- target_sources(leveldb
- PRIVATE
- "util/env_posix.cc"
- "util/posix_logger.h"
- )
- endif (WIN32)
-
- # MemEnv is not part of the interface and could be pulled to a separate library.
- target_sources(leveldb
- PRIVATE
- "helpers/memenv/memenv.cc"
- "helpers/memenv/memenv.h"
- )
-
- target_include_directories(leveldb
- PUBLIC
- $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
- $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
- )
-
- set_target_properties(leveldb
- PROPERTIES VERSION ${PROJECT_VERSION} SOVERSION ${PROJECT_VERSION_MAJOR})
-
- target_compile_definitions(leveldb
- PRIVATE
- # Used by include/export.h when building shared libraries.
- LEVELDB_COMPILE_LIBRARY
- # Used by port/port.h.
- ${LEVELDB_PLATFORM_NAME}=1
- )
- if (NOT HAVE_CXX17_HAS_INCLUDE)
- target_compile_definitions(leveldb
- PRIVATE
- LEVELDB_HAS_PORT_CONFIG_H=1
- )
- endif(NOT HAVE_CXX17_HAS_INCLUDE)
-
- if(BUILD_SHARED_LIBS)
- target_compile_definitions(leveldb
- PUBLIC
- # Used by include/export.h.
- LEVELDB_SHARED_LIBRARY
- )
- endif(BUILD_SHARED_LIBS)
-
- if(HAVE_CLANG_THREAD_SAFETY)
- target_compile_options(leveldb
- PUBLIC
- -Werror -Wthread-safety)
- endif(HAVE_CLANG_THREAD_SAFETY)
-
- if(HAVE_CRC32C)
- target_link_libraries(leveldb crc32c)
- endif(HAVE_CRC32C)
- if(HAVE_SNAPPY)
- target_link_libraries(leveldb snappy)
- endif(HAVE_SNAPPY)
- if(HAVE_TCMALLOC)
- target_link_libraries(leveldb tcmalloc)
- endif(HAVE_TCMALLOC)
-
- # Needed by port_stdcxx.h
- find_package(Threads REQUIRED)
- target_link_libraries(leveldb Threads::Threads)
-
- add_executable(leveldbutil
- "db/leveldbutil.cc"
- )
- target_link_libraries(leveldbutil leveldb)
-
- if(LEVELDB_BUILD_TESTS)
- enable_testing()
-
- # Prevent overriding the parent project's compiler/linker settings on Windows.
- set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
- set(install_gtest OFF)
- set(install_gmock OFF)
- set(build_gmock ON)
-
- # This project is tested using GoogleTest.
- add_subdirectory("third_party/googletest")
-
- # This project uses Google benchmark for benchmarking.
- set(BENCHMARK_ENABLE_TESTING OFF CACHE BOOL "" FORCE)
- set(BENCHMARK_ENABLE_EXCEPTIONS OFF CACHE BOOL "" FORCE)
- add_subdirectory("third_party/benchmark")
-
- # GoogleTest triggers a missing field initializers warning.
- if(LEVELDB_HAVE_NO_MISSING_FIELD_INITIALIZERS)
- set_property(TARGET gtest
- APPEND PROPERTY COMPILE_OPTIONS -Wno-missing-field-initializers)
- set_property(TARGET gmock
- APPEND PROPERTY COMPILE_OPTIONS -Wno-missing-field-initializers)
- endif(LEVELDB_HAVE_NO_MISSING_FIELD_INITIALIZERS)
-
- function(leveldb_test test_file)
- get_filename_component(test_target_name "${test_file}" NAME_WE)
-
- add_executable("${test_target_name}" "")
- target_sources("${test_target_name}"
- PRIVATE
- "${PROJECT_BINARY_DIR}/${LEVELDB_PORT_CONFIG_DIR}/port_config.h"
- "util/testutil.cc"
- "util/testutil.h"
-
- "${test_file}"
- )
- target_link_libraries("${test_target_name}" leveldb gmock gtest benchmark)
- target_compile_definitions("${test_target_name}"
- PRIVATE
- ${LEVELDB_PLATFORM_NAME}=1
- )
- if (NOT HAVE_CXX17_HAS_INCLUDE)
- target_compile_definitions("${test_target_name}"
- PRIVATE
- LEVELDB_HAS_PORT_CONFIG_H=1
- )
- endif(NOT HAVE_CXX17_HAS_INCLUDE)
-
- add_test(NAME "${test_target_name}" COMMAND "${test_target_name}")
- endfunction(leveldb_test)
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- leveldb_test("db/c_test.c")
- leveldb_test("db/fault_injection_test.cc")
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- leveldb_test("issues/issue178_test.cc")
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- leveldb_test("issues/issue320_test.cc")
-
- leveldb_test("util/env_test.cc")
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-
- if(NOT BUILD_SHARED_LIBS)
- leveldb_test("db/autocompact_test.cc")
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- leveldb_test("db/recovery_test.cc")
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- leveldb_test("db/version_set_test.cc")
- leveldb_test("db/write_batch_test.cc")
-
- leveldb_test("helpers/memenv/memenv_test.cc")
-
- leveldb_test("table/filter_block_test.cc")
- leveldb_test("table/table_test.cc")
-
- leveldb_test("util/arena_test.cc")
- leveldb_test("util/bloom_test.cc")
- leveldb_test("util/cache_test.cc")
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- leveldb_test("util/crc32c_test.cc")
- leveldb_test("util/hash_test.cc")
- leveldb_test("util/logging_test.cc")
-
- # TODO(costan): This test also uses
- # "util/env_{posix|windows}_test_helper.h"
- if (WIN32)
- leveldb_test("util/env_windows_test.cc")
- else (WIN32)
- leveldb_test("util/env_posix_test.cc")
- endif (WIN32)
- endif(NOT BUILD_SHARED_LIBS)
- endif(LEVELDB_BUILD_TESTS)
-
- if(LEVELDB_BUILD_BENCHMARKS)
- function(leveldb_benchmark bench_file)
- get_filename_component(bench_target_name "${bench_file}" NAME_WE)
-
- add_executable("${bench_target_name}" "")
- target_sources("${bench_target_name}"
- PRIVATE
- "${PROJECT_BINARY_DIR}/${LEVELDB_PORT_CONFIG_DIR}/port_config.h"
- "util/histogram.cc"
- "util/histogram.h"
- "util/testutil.cc"
- "util/testutil.h"
-
- "${bench_file}"
- )
- target_link_libraries("${bench_target_name}" leveldb gmock gtest)
- target_compile_definitions("${bench_target_name}"
- PRIVATE
- ${LEVELDB_PLATFORM_NAME}=1
- )
- if (NOT HAVE_CXX17_HAS_INCLUDE)
- target_compile_definitions("${bench_target_name}"
- PRIVATE
- LEVELDB_HAS_PORT_CONFIG_H=1
- )
- endif(NOT HAVE_CXX17_HAS_INCLUDE)
- endfunction(leveldb_benchmark)
-
- if(NOT BUILD_SHARED_LIBS)
- leveldb_benchmark("benchmarks/db_bench.cc")
- endif(NOT BUILD_SHARED_LIBS)
-
- check_library_exists(sqlite3 sqlite3_open "" HAVE_SQLITE3)
- if(HAVE_SQLITE3)
- leveldb_benchmark("benchmarks/db_bench_sqlite3.cc")
- target_link_libraries(db_bench_sqlite3 sqlite3)
- endif(HAVE_SQLITE3)
-
- # check_library_exists is insufficient here because the library names have
- # different manglings when compiled with clang or gcc, at least when installed
- # with Homebrew on Mac.
- set(OLD_CMAKE_REQURED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
- list(APPEND CMAKE_REQUIRED_LIBRARIES kyotocabinet)
- check_cxx_source_compiles("
- #include <kcpolydb.h>
-
- int main() {
- kyotocabinet::TreeDB* db = new kyotocabinet::TreeDB();
- delete db;
- return 0;
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- " HAVE_KYOTOCABINET)
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-
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- ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
- )
- install(
- FILES
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- "${LEVELDB_PUBLIC_INCLUDE_DIR}/table.h"
- "${LEVELDB_PUBLIC_INCLUDE_DIR}/write_batch.h"
- DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/leveldb"
- )
-
- include(CMakePackageConfigHelpers)
- configure_package_config_file(
- "cmake/${PROJECT_NAME}Config.cmake.in"
- "${PROJECT_BINARY_DIR}/cmake/${PROJECT_NAME}Config.cmake"
- INSTALL_DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}"
- )
- write_basic_package_version_file(
- "${PROJECT_BINARY_DIR}/cmake/${PROJECT_NAME}ConfigVersion.cmake"
- COMPATIBILITY SameMajorVersion
- )
- install(
- EXPORT leveldbTargets
- NAMESPACE leveldb::
- DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}"
- )
- install(
- FILES
- "${PROJECT_BINARY_DIR}/cmake/${PROJECT_NAME}Config.cmake"
- "${PROJECT_BINARY_DIR}/cmake/${PROJECT_NAME}ConfigVersion.cmake"
- DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}"
- )
- endif(LEVELDB_INSTALL)
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