c8d/push: Ignore :port when comparing source repository

Distribution source labels don't store port of the repository. If the
content was obtained from repository 172.17.0.2:5000 then its
corresponding label will have a key "containerd.io/distribution.source.172.17.0.2".

Fix the check in canBeMounted to ignore the :port part of the domain.

This also removes the check which prevented insecure repositories to use
cross-repo mount - the real cause was the mismatch in domain comparison.

Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>

daemon/containerd/image_push.go

@@ -73,7 +73,7 @@ func (i *ImageService) PushImage(ctx context.Context, targetRef reference.Named,
 
 	var limiter *semaphore.Weighted = nil // TODO: Respect max concurrent downloads/uploads
 
-	mountableBlobs, err := i.findMissingMountable(ctx, store, jobs, target, targetRef, limiter)
+	mountableBlobs, err := findMissingMountable(ctx, store, jobs, target, targetRef, limiter)
 	if err != nil {
 		return err
 	}
@@ -146,7 +146,7 @@ func (i *ImageService) PushImage(ctx context.Context, targetRef reference.Named,
 // findMissingMountable will walk the target descriptor recursively and return
 // missing contents with their distribution source which could potentially
 // be cross-repo mounted.
-func (i *ImageService) findMissingMountable(ctx context.Context, store content.Store, jobs *jobs,
+func findMissingMountable(ctx context.Context, store content.Store, jobs *jobs,
 	target ocispec.Descriptor, targetRef reference.Named, limiter *semaphore.Weighted,
 ) (map[digest.Digest]distributionSource, error) {
 	mountableBlobs := map[digest.Digest]distributionSource{}
@@ -169,7 +169,7 @@ func (i *ImageService) findMissingMountable(ctx context.Context, store content.S
 			}
 
 			for _, source := range sources {
-				if canBeMounted(desc.MediaType, targetRef, i.registryService.IsInsecureRegistry, source) {
+				if canBeMounted(desc.MediaType, targetRef, source) {
 					mutex.Lock()
 					mountableBlobs[desc.Digest] = source
 					mutex.Unlock()
@@ -252,7 +252,7 @@ func (source distributionSource) GetReference(dgst digest.Digest) (reference.Nam
 
 // canBeMounted returns if the content with given media type can be cross-repo
 // mounted when pushing it to a remote reference ref.
-func canBeMounted(mediaType string, targetRef reference.Named, isInsecureFunc func(string) bool, source distributionSource) bool {
+func canBeMounted(mediaType string, targetRef reference.Named, source distributionSource) bool {
 	if containerdimages.IsManifestType(mediaType) {
 		return false
 	}
@@ -261,11 +261,10 @@ func canBeMounted(mediaType string, targetRef reference.Named, isInsecureFunc fu
 	}
 
 	reg := reference.Domain(targetRef)
-
-	// Cross-repo mount doesn't seem to work with insecure registries.
-	isInsecure := isInsecureFunc(reg)
-	if isInsecure {
-		return false
+	// Remove :port suffix from domain
+	// containerd distribution source label doesn't store port
+	if portIdx := strings.LastIndex(reg, ":"); portIdx != -1 {
+		reg = reg[:portIdx]
 	}
 
 	// If the source registry is the same as the one we are pushing to