Add a fallback to full sync if fcntl(F_BARRIERFSYNC) fails (#5806)

* Add a fallback to full sync if fcntl(F_BARRIERFSYNC) fails

F_BARRIERFSYNC is available on HFS and APFS, but is not supported
on filesystems such as exFAT.

* conditionally run a sync test

* more robust paths for various build types

CHANGELOG.md

@@ -19,6 +19,7 @@
 * Fix all UBSan failures hit by tests. It is unclear if any of these manifested as visible bugs. ([PR #5665](https://github.com/realm/realm-core/pull/5665))
 * Fix sorting order for `realm_query_find_first` in the C API.([#5720](https://github.com/realm/realm-core/issues/5720))
 * Upload completion callbacks may have called before the download message that completed them was fully integrated. ([#4865](https://github.com/realm/realm-core/issues/4865)).
+* Fixed an exception "fcntl() with F_BARRIERFSYNC failed: Inappropriate ioctl for device" when running with MacOS on an exFAT drive. ([#5789](https://github.com/realm/realm-core/issues/5789) since 12.0.0) 
 * Syncing of a Decimal128 with big significand could result in a crash. ([#5728](https://github.com/realm/realm-core/issues/5728))
 
 

evergreen/config.yml

@@ -369,6 +369,17 @@ tasks:
         xcrun swift build
         xcrun swift run ObjectStoreTests
 
+- name: test-on-exfat
+  commands:
+  - func: "fetch source"
+  - func: "fetch binaries"
+  - func: "compile"
+  - command: shell.exec
+    params:
+      working_dir: realm-core/build
+      shell: /bin/bash
+      script: ../tools/run-tests-on-exfat.sh
+
 - name: bloaty
   commands:
   - func: "fetch source"
@@ -899,6 +910,7 @@ buildvariants:
   - name: benchmarks
   - name: long-running-tests
   - name: swift-build-and-test
+  - name: test-on-exfat
 
 - name: macos-1100-arm64
   display_name: "MacOS 11 arm64"

src/realm/util/file.cpp

@@ -1044,10 +1044,10 @@ void File::barrier()
 #if REALM_PLATFORM_APPLE
     if (::fcntl(m_fd, F_BARRIERFSYNC) == 0)
         return;
-    throw std::system_error(errno, std::system_category(), "fcntl() with F_BARRIERFSYNC failed");
-#else
-    sync();
+        // If fcntl fails, we fallback to full sync.
+        // This is known to occur on exFAT which does not support F_BARRIERSYNC.
 #endif
+    sync();
 }
 
 #ifndef _WIN32

test/test_all.cpp

@@ -545,7 +545,7 @@ bool run_tests(util::Logger* logger)
 } // anonymous namespace
 
 
-int test_all(util::Logger* logger, bool disable_all_sync_to_disk)
+int test_all(util::Logger* logger)
 {
     // General note: Some Github clients on Windows will interfere with the .realm files created by unit tests (the
     // git client will attempt to access the files when it sees that new files have been created). This may cause
@@ -563,7 +563,8 @@ int test_all(util::Logger* logger, bool disable_all_sync_to_disk)
     // e.g. due to power off.
     // NOTE: This is not strictly true. If encryption is enabled, a crash of the testsuite
     // (not the whole platform) may produce corrupt realm files.
-    if (disable_all_sync_to_disk)
+    char* enable_sync_to_disk = getenv("UNITTEST_ENABLE_SYNC_TO_DISK");
+    if (!enable_sync_to_disk)
         disable_sync_to_disk();
 #endif
 

test/test_all.hpp

@@ -21,6 +21,6 @@
 
 #include <realm/util/logger.hpp>
 
-int test_all(realm::util::Logger* = nullptr, bool disable_all_sync_to_disk = true);
+int test_all(realm::util::Logger* = nullptr);
 
 #endif // REALM_TEST_TEST_ALL_HPP

test/test_transform.cpp

@@ -972,8 +972,8 @@ TEST(Transform_EraseSelectedLinkView)
     }
 }
 
-
-TEST(Transform_Randomized)
+// this test can take upwards of an hour if sync to disk is enabled
+TEST_IF(Transform_Randomized, get_disable_sync_to_disk())
 {
     const char* trace_p = ::getenv("UNITTEST_RANDOMIZED_TRACE");
     bool trace = trace_p && (StringData{trace_p} != "no");

test/util/test_path.cpp

@@ -161,7 +161,9 @@ bool test_dir_is_exfat()
     REALM_ASSERT_RELEASE(ret == 0);
     // The documentation and headers helpfully don't list any of the values of
     // f_type or provide constants for them
-    return fsbuf.f_type == 28 /* exFAT */;
+    std::string fs_typename = fsbuf.f_fstypename;
+    std::transform(fs_typename.begin(), fs_typename.end(), fs_typename.begin(), toLowerAscii);
+    return fs_typename.find(std::string("exfat")) != std::string::npos;
 #else
     return false;
 #endif

tools/run-tests-on-exfat.sh

@@ -1,15 +1,24 @@
 #!/usr/bin/env bash
 
-set -e
+set -e -x
 
 readonly build_dir="$PWD"
 readonly dmg_file="$build_dir/exfat.dmg"
 
-if ! [ -f "$build_dir/test/realm-tests" ]; then
+build_prefix="not found"
+if [ -f "$build_dir/test/realm-tests.app/Contents/MacOS/realm-tests" ]; then
+    build_prefix="$build_dir/test/"
+elif [ -f "$build_dir/test/Release/realm-tests.app/Contents/MacOS/realm-tests" ]; then
+    build_prefix="$build_dir/test/Release/"
+elif [ -f "$build_dir/test/Debug/realm-tests.app/Contents/MacOS/realm-tests" ]; then
+    build_prefix="$build_dir/test/Debug/"
+else
     echo 'Run this script from the build directory after building tests'
     exit 1
 fi
 
+echo "using path prefix $build_prefix"
+
 function cleanup() {
     rm -f "$dmg_file"
     if [ -n "$device" ]; then
@@ -19,10 +28,12 @@ function cleanup() {
 trap cleanup EXIT
 
 rm -f "$dmg_file"
-hdiutil create -fs exFAT -size 100MB "$dmg_file"
+hdiutil create -fs exFAT -size 400MB "$dmg_file"
 hdiutil_out=$(hdiutil attach exfat.dmg)
 device=$(echo "$hdiutil_out" | head -n1 | cut -f1 | awk '{$1=$1};1')
 path=$(echo "$hdiutil_out" | tail -n1 | cut -f3)
 
-./test/realm-tests "$path/"
+UNITTEST_ENABLE_SYNC_TO_DISK=1 "$build_prefix/realm-tests.app/Contents/MacOS/realm-tests" "$path/"
+UNITTEST_ENABLE_SYNC_TO_DISK=1 "$build_prefix/realm-sync-tests.app/Contents/MacOS/realm-sync-tests" "$path/"
+echo "finished running tests"