go.etcd.io/etcd@v3.3.27+incompatible/pkg/fileutil/preallocate_unix.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 fileutil
    18  
    19  import (
    20  	"os"
    21  	"syscall"
    22  )
    23  
    24  func preallocExtend(f *os.File, sizeInBytes int64) error {
    25  	// use mode = 0 to change size
    26  	err := syscall.Fallocate(int(f.Fd()), 0, 0, sizeInBytes)
    27  	if err != nil {
    28  		errno, ok := err.(syscall.Errno)
    29  		// not supported; fallback
    30  		// fallocate EINTRs frequently in some environments; fallback
    31  		if ok && (errno == syscall.ENOTSUP || errno == syscall.EINTR) {
    32  			return preallocExtendTrunc(f, sizeInBytes)
    33  		}
    34  	}
    35  	return err
    36  }
    37  
    38  func preallocFixed(f *os.File, sizeInBytes int64) error {
    39  	// use mode = 1 to keep size; see FALLOC_FL_KEEP_SIZE
    40  	err := syscall.Fallocate(int(f.Fd()), 1, 0, sizeInBytes)
    41  	if err != nil {
    42  		errno, ok := err.(syscall.Errno)
    43  		// treat not supported as nil error
    44  		if ok && errno == syscall.ENOTSUP {
    45  			return nil
    46  		}
    47  	}
    48  	return err
    49  }