volume/volume_linux.go

   1 // +build linux
   2
   3 package volume
   4
   5 import (
   6         "fmt"
   7         "strings"
   8
   9         mounttypes "github.com/docker/docker/api/types/mount"
  10 )
  11
  12 // ConvertTmpfsOptions converts *mounttypes.TmpfsOptions to the raw option string
  13 // for mount(2).
  14 func ConvertTmpfsOptions(opt *mounttypes.TmpfsOptions, readOnly bool) (string, error) {
  15         var rawOpts []string
  16         if readOnly {
  17                 rawOpts = append(rawOpts, "ro")
  18         }
  19
  20         if opt != nil && opt.Mode != 0 {
  21                 rawOpts = append(rawOpts, fmt.Sprintf("mode=%o", opt.Mode))
  22         }
  23
  24         if opt != nil && opt.SizeBytes != 0 {
  25                 // calculate suffix here, making this linux specific, but that is
  26                 // okay, since API is that way anyways.
  27
  28                 // we do this by finding the suffix that divides evenly into the
  29                 // value, returing the value itself, with no suffix, if it fails.
  30                 //
  31                 // For the most part, we don't enforce any semantic to this values.
  32                 // The operating system will usually align this and enforce minimum
  33                 // and maximums.
  34                 var (
  35                         size   = opt.SizeBytes
  36                         suffix string
  37                 )
  38                 for _, r := range []struct {
  39                         suffix  string
  40                         divisor int64
  41                 }{
  42                         {"g", 1 << 30},
  43                         {"m", 1 << 20},
  44                         {"k", 1 << 10},
  45                 } {
  46                         if size%r.divisor == 0 {
  47                                 size = size / r.divisor
  48                                 suffix = r.suffix
  49                                 break
  50                         }
  51                 }
  52
  53                 rawOpts = append(rawOpts, fmt.Sprintf("size=%d%s", size, suffix))
  54         }
  55         return strings.Join(rawOpts, ","), nil
  56 }