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Merge pull request #4178 from alexlarsson/fix-aufs-plnk

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archive: Handle aufs plink hardlinks in ApplyLayer
This commit is contained in:
Victor Vieux 2014-02-17 11:48:39 -08:00
commit 8f140b2ded
2 changed files with 42 additions and 2 deletions
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2
archive/archive.go
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@ -186,7 +186,7 @@ func addTarFile(path, name string, tw *tar.Writer) error {
return nil
}
func createTarFile(path, extractDir string, hdr *tar.Header, reader *tar.Reader) error {
func createTarFile(path, extractDir string, hdr *tar.Header, reader io.Reader) error {
switch hdr.Typeflag {
case tar.TypeDir:
// Create directory unless it exists as a directory already.

42
archive/diff.go
View file

@ -2,7 +2,9 @@ package archive
import (
"code.google.com/p/go/src/pkg/archive/tar"
"fmt"
"io"
"io/ioutil"
"os"
"path/filepath"
"strings"
@ -42,6 +44,9 @@ func ApplyLayer(dest string, layer ArchiveReader) error {
var dirs []*tar.Header
aufsTempdir := ""
aufsHardlinks := make(map[string]*tar.Header)
// Iterate through the files in the archive.
for {
hdr, err := tr.Next()
@ -72,6 +77,22 @@ func ApplyLayer(dest string, layer ArchiveReader) error {
// Skip AUFS metadata dirs
if strings.HasPrefix(hdr.Name, ".wh..wh.") {
// Regular files inside /.wh..wh.plnk can be used as hardlink targets
// We don't want this directory, but we need the files in them so that
// such hardlinks can be resolved.
if strings.HasPrefix(hdr.Name, ".wh..wh.plnk") && hdr.Typeflag == tar.TypeReg {
basename := filepath.Base(hdr.Name)
aufsHardlinks[basename] = hdr
if aufsTempdir == "" {
if aufsTempdir, err = ioutil.TempDir("", "dockerplnk"); err != nil {
return err
}
defer os.RemoveAll(aufsTempdir)
}
if err := createTarFile(filepath.Join(aufsTempdir, basename), dest, hdr, tr); err != nil {
return err
}
}
continue
}
@ -96,7 +117,26 @@ func ApplyLayer(dest string, layer ArchiveReader) error {
}
}
if err := createTarFile(path, dest, hdr, tr); err != nil {
srcData := io.Reader(tr)
srcHdr := hdr
// Hard links into /.wh..wh.plnk don't work, as we don't extract that directory, so
// we manually retarget these into the temporary files we extracted them into
if hdr.Typeflag == tar.TypeLink && strings.HasPrefix(filepath.Clean(hdr.Linkname), ".wh..wh.plnk") {
linkBasename := filepath.Base(hdr.Linkname)
srcHdr = aufsHardlinks[linkBasename]
if srcHdr == nil {
return fmt.Errorf("Invalid aufs hardlink")
}
tmpFile, err := os.Open(filepath.Join(aufsTempdir, linkBasename))
if err != nil {
return err
}
defer tmpFile.Close()
srcData = tmpFile
}
if err := createTarFile(path, dest, srcHdr, srcData); err != nil {
return err
}