github.com/petermattis/pebble@v0.0.0-20190905164901-ab51a2166067/vfs/preallocate_linux.go (about)

     1  // Copyright 2016 The etcd Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // +build linux
    16  
    17  package vfs
    18  
    19  import (
    20  	"syscall"
    21  )
    22  
    23  func preallocExtend(fd uintptr, offset, length int64) error {
    24  	err := syscall.Fallocate(int(fd), 0 /* mode */, offset, length)
    25  	if err != nil {
    26  		errno, ok := err.(syscall.Errno)
    27  		// not supported; fallback
    28  		// fallocate EINTRs frequently in some environments; fallback
    29  		if ok && (errno == syscall.ENOTSUP || errno == syscall.EINTR) {
    30  			return syscall.Ftruncate(int(fd), offset+length)
    31  		}
    32  	}
    33  	return err
    34  }