diff --git a/vendor/go.etcd.io/etcd/pkg/fileutil/preallocate_darwin.go b/vendor/go.etcd.io/etcd/pkg/fileutil/preallocate_darwin.go
new file mode 100644
index 0000000..5a6dccf
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/pkg/fileutil/preallocate_darwin.go
@@ -0,0 +1,65 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build darwin
+
+package fileutil
+
+import (
+	"os"
+	"syscall"
+	"unsafe"
+)
+
+func preallocExtend(f *os.File, sizeInBytes int64) error {
+	if err := preallocFixed(f, sizeInBytes); err != nil {
+		return err
+	}
+	return preallocExtendTrunc(f, sizeInBytes)
+}
+
+func preallocFixed(f *os.File, sizeInBytes int64) error {
+	// allocate all requested space or no space at all
+	// TODO: allocate contiguous space on disk with F_ALLOCATECONTIG flag
+	fstore := &syscall.Fstore_t{
+		Flags:   syscall.F_ALLOCATEALL,
+		Posmode: syscall.F_PEOFPOSMODE,
+		Length:  sizeInBytes}
+	p := unsafe.Pointer(fstore)
+	_, _, errno := syscall.Syscall(syscall.SYS_FCNTL, f.Fd(), uintptr(syscall.F_PREALLOCATE), uintptr(p))
+	if errno == 0 || errno == syscall.ENOTSUP {
+		return nil
+	}
+
+	// wrong argument to fallocate syscall
+	if errno == syscall.EINVAL {
+		// filesystem "st_blocks" are allocated in the units of
+		// "Allocation Block Size" (run "diskutil info /" command)
+		var stat syscall.Stat_t
+		syscall.Fstat(int(f.Fd()), &stat)
+
+		// syscall.Statfs_t.Bsize is "optimal transfer block size"
+		// and contains matching 4096 value when latest OS X kernel
+		// supports 4,096 KB filesystem block size
+		var statfs syscall.Statfs_t
+		syscall.Fstatfs(int(f.Fd()), &statfs)
+		blockSize := int64(statfs.Bsize)
+
+		if stat.Blocks*blockSize >= sizeInBytes {
+			// enough blocks are already allocated
+			return nil
+		}
+	}
+	return errno
+}