dilim/containerd
1
0
Fork 0
mirror of https://github.com/containerd/containerd.git synced 2026-08-09 09:33:06 +00:00
Code Issues Packages Projects Releases Wiki Activity

Merge pull request #13185 from erofs/erofs-layers

Browse Source 
erofs-differ: support zstd-wrapped EROFS layers
This commit is contained in:
Fu Wei
2026-04-12 22:20:11 +00:00
committed by GitHub
parent 83044a43a1 b9445fb9ef
commit 997f813b5c
1 changed files with 50 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

71
plugins/diff/erofs/differ.go
View File

@@ -98,20 +98,8 @@ func NewErofsDiffer(store content.Store, opts ...DifferOpt) differ {
return d
}
// Please avoid using any +suffix to list the algorithms used inside EROFS
// blobs, since:
// - Each EROFS layer can use multiple compression algorithms;
// - The suffixes should only indicate the corresponding preprocessor for
// `images.DiffCompression`.
//
// Since `images.DiffCompression` doesn't support arbitrary media types,
// disallow non-empty suffixes for now.
func isErofsMediaType(mt string) bool {
if !strings.HasSuffix(mt, ".erofs") && !strings.HasPrefix(mt, "application/vnd.erofs.layer") {
return false
}
_, _, hasExt := strings.Cut(mt, "+")
return !hasExt
return strings.HasSuffix(mt, ".erofs") || strings.HasPrefix(mt, "application/vnd.erofs.layer")
}
func (s erofsDiff) Apply(ctx context.Context, desc ocispec.Descriptor, mounts []mount.Mount, opts ...diff.ApplyOpt) (d ocispec.Descriptor, err error) {
@@ -127,11 +115,32 @@ func (s erofsDiff) Apply(ctx context.Context, desc ocispec.Descriptor, mounts []
}
}()
native := false
if isErofsMediaType(desc.MediaType) {
native = true
} else if _, err := images.DiffCompression(ctx, desc.MediaType); err != nil {
return emptyDesc, fmt.Errorf("currently unsupported media type: %s", desc.MediaType)
var (
erofsLayerType string
fastcopy bool
)
diffLayerType := desc.MediaType
native := isErofsMediaType(diffLayerType)
if native {
base, ext, hasExt := strings.Cut(diffLayerType, "+")
// Mimic the OCI layer for EROFS blobs for diff.NewProcessorChain(), so
// there is no need to bother with too much unrelated logic for now.
diffLayerType = ocispec.MediaTypeImageLayer
if hasExt {
// `+zstd` indicates that the original EROFS blob is additionally
// compressed with standard zstd streams.
// Only `+zstd` is considered since it is more performant than gzip
// and has useful features like skippable frames.
if ext != "zstd" {
return emptyDesc, fmt.Errorf("unsupported erofs layer suffix: %s", ext)
}
diffLayerType = diffLayerType + "+zstd"
} else {
fastcopy = true
}
erofsLayerType = base
} else if _, err := images.DiffCompression(ctx, diffLayerType); err != nil {
return emptyDesc, fmt.Errorf("unsupported media type: %s", desc.MediaType)
}
var config diff.ApplyConfig
@@ -153,7 +162,8 @@ func (s erofsDiff) Apply(ctx context.Context, desc ocispec.Descriptor, mounts []
defer ra.Close()
layerBlobPath := path.Join(layer, "layer.erofs")
if native {
// Allow copy file range when there is an uncompressed native EROFS layer
if fastcopy {
f, err := os.Create(layerBlobPath)
if err != nil {
return emptyDesc, err
@@ -163,10 +173,11 @@ func (s erofsDiff) Apply(ctx context.Context, desc ocispec.Descriptor, mounts []
if err != nil {
return emptyDesc, err
}
log.G(ctx).WithField("path", layerBlobPath).Debug("Applied layer with uncompressed EROFS blob")
return desc, nil
}
processor := diff.NewProcessorChain(desc.MediaType, content.NewReader(ra))
processor := diff.NewProcessorChain(diffLayerType, content.NewReader(ra))
for {
if processor, err = diff.GetProcessor(ctx, processor, config.ProcessorPayloads); err != nil {
return emptyDesc, fmt.Errorf("failed to get stream processor for %s: %w", desc.MediaType, err)
@@ -185,7 +196,18 @@ func (s erofsDiff) Apply(ctx context.Context, desc ocispec.Descriptor, mounts []
// Choose between tar index or tar conversion mode
// Generate deterministic UUID from layer digest
u := uuid.NewSHA1(uuid.NameSpaceURL, []byte("erofs:blobs/"+desc.Digest))
if s.enableTarIndex {
if native {
f, err := os.Create(layerBlobPath)
if err != nil {
return emptyDesc, err
}
_, err = io.Copy(f, rc)
f.Close()
if err != nil {
return emptyDesc, err
}
log.G(ctx).WithField("path", layerBlobPath).Debug("Applied layer with compressed EROFS blob")
} else if s.enableTarIndex {
// Use the tar index method: generate tar index and append tar
err = erofsutils.GenerateTarIndexAndAppendTar(ctx, rc, layerBlobPath, u.String(), s.mkfsExtraOpts)
if err != nil {
@@ -213,6 +235,13 @@ func (s erofsDiff) Apply(ctx context.Context, desc ocispec.Descriptor, mounts []
}
}
if native {
return ocispec.Descriptor{
MediaType: erofsLayerType,
Size: rc.c,
Digest: digester.Digest(),
}, nil
}
return ocispec.Descriptor{
MediaType: ocispec.MediaTypeImageLayer,
Size: rc.c,