Re: [PATCH v3 2/6] core.fsyncobjectfiles: batched disk flushes

diff --git a/config.c b/config.c
index cb4a8058bff..9fe3602e1c4 100644
--- a/config.c
+++ b/config.c

@@ -1509,7 +1509,13 @@ static int git_default_core_config(const char *var, const char *value, void *cb)
 	}
 
 	if (!strcmp(var, "core.fsyncobjectfiles")) {
-		fsync_object_files = git_config_bool(var, value);
+		if (!value)
+			return config_error_nonbool(var);
+		if (!strcasecmp(value, "batch"))
+			fsync_object_files = FSYNC_OBJECT_FILES_BATCH;
+		else
+			fsync_object_files = git_config_bool(var, value)
+				? FSYNC_OBJECT_FILES_ON : FSYNC_OBJECT_FILES_OFF;
 		return 0;

-/* Finalize a file on disk, and close it. */
-static void close_loose_object(int fd)
-{
-	if (fsync_object_files)
-		fsync_or_die(fd, "loose object file");
-	if (close(fd) != 0)
-		die_errno(_("error when closing loose object file"));
-}
-
 /* Size of directory component, including the ending '/' */
 static inline int directory_size(const char *filename)
 {

@@ -1973,17 +1964,8 @@ static int write_loose_object(const struct object_id *oid, char *hdr,
 		die(_("confused by unstable object source data for %s"),
 		    oid_to_hex(oid));
 
-	close_loose_object(fd);
-
-	if (mtime) {
-		struct utimbuf utb;
-		utb.actime = mtime;
-		utb.modtime = mtime;
-		if (utime(tmp_file.buf, &utb) < 0)
-			warning_errno(_("failed utime() on %s"), tmp_file.buf);
-	}
-
-	return finalize_object_file(tmp_file.buf, filename.buf);
+	return fsync_and_close_loose_object_bulk_checkin(fd, tmp_file.buf,
+							 filename.buf, mtime);
 }

+int git_fsync(int fd, enum fsync_action action)
+{
+	if (action == FSYNC_WRITEOUT_ONLY) {
+#ifdef __APPLE__
+		/*
+		 * on Mac OS X, fsync just causes filesystem cache writeback but does not
+		 * flush hardware caches.
+		 */
+		return fsync(fd);
+#endif
+
+#ifdef HAVE_SYNC_FILE_RANGE
+		/*
+		 * On linux 2.6.17 and above, sync_file_range is the way to issue
+		 * a writeback without a hardware flush. An offset of 0 and size of 0
+		 * indicates writeout of the entire file and the wait flags ensure that all
+		 * dirty data is written to the disk (potentially in a disk-side cache)
+		 * before we continue.
+		 */
+
+		return sync_file_range(fd, 0, 0, SYNC_FILE_RANGE_WAIT_BEFORE |
+						 SYNC_FILE_RANGE_WRITE |
+						 SYNC_FILE_RANGE_WAIT_AFTER);
+#endif
+
+		errno = ENOSYS;
+		return -1;
+	}

+#ifdef __APPLE__
+	return fcntl(fd, F_FULLFSYNC);
+#else
+	return fsync(fd);
+#endif
+}