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Add basic support for .wh..wh..opq

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This fixes the case where directory is removed in
aufs and then the same layer is imported to a
different graphdriver.

Currently when you do `rm -rf /foo && mkdir /foo`
in a layer in aufs the files under `foo` would
only be be hidden on aufs.

The problems with this fix:

1) When a new diff is recreated from non-aufs driver
the `opq` files would not be there. This should not
mean layer differences for the user but still
different content in the tar (one would have one
`opq` file, the others would have `.wh.*` for every
file inside that folder). This difference also only
happens if the tar-split file isn’t stored for the
layer.

2) New files that have the filenames before `.wh..wh..opq`
when they are sorted do not get picked up by non-aufs
graphdrivers. Fixing this would require a bigger
refactoring that is planned in the future.


Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>
This commit is contained in:
Tonis Tiigi 2015-09-21 14:36:35 -07:00
parent 985b7ec895
commit 00e3277107
2 changed files with 22 additions and 5 deletions
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2
daemon/graphdriver/aufs/aufs.go
View file

@ -322,7 +322,7 @@ func (a *Driver) Diff(id, parent string) (archive.Archive, error) {
// AUFS doesn't need the parent layer to produce a diff.
return archive.TarWithOptions(path.Join(a.rootPath(), "diff", id), &archive.TarOptions{
Compression: archive.Uncompressed,
ExcludePatterns: []string{".wh..wh.*"},
ExcludePatterns: []string{".wh..wh.*", "!.wh..wh..opq"},
})
}

19
pkg/archive/diff.go
View file

@ -100,8 +100,11 @@ func UnpackLayer(dest string, layer Reader) (size int64, err error) {
return 0, err
}
}
if hdr.Name != ".wh..wh..opq" {
continue
}
}
path := filepath.Join(dest, hdr.Name)
rel, err := filepath.Rel(dest, path)
if err != nil {
@ -116,10 +119,24 @@ func UnpackLayer(dest string, layer Reader) (size int64, err error) {
if strings.HasPrefix(base, ".wh.") {
originalBase := base[len(".wh."):]
originalPath := filepath.Join(filepath.Dir(path), originalBase)
dir := filepath.Dir(path)
if originalBase == ".wh..opq" {
fi, err := os.Lstat(dir)
if err != nil && !os.IsNotExist(err) {
return 0, err
}
if err := os.RemoveAll(dir); err != nil {
return 0, err
}
if err := os.Mkdir(dir, fi.Mode()&os.ModePerm); err != nil {
return 0, err
}
} else {
originalPath := filepath.Join(dir, originalBase)
if err := os.RemoveAll(originalPath); err != nil {
return 0, err
}
}
} else {
// If path exits we almost always just want to remove and replace it.
// The only exception is when it is a directory *and* the file from