metadata backends inconsistently use .meta.lock vs .mpk vs .mlock

[butonic]

The messagepack_backend.go has:

// IsMetaFile returns whether the given path represents a meta file
func (MessagePackBackend) IsMetaFile(path string) bool {
	return strings.HasSuffix(path, ".mpk") || strings.HasSuffix(path, ".mlock")
}

// ...

// MetadataPath returns the path of the file holding the metadata for the given path
func (MessagePackBackend) MetadataPath(n MetadataNode) string { return n.InternalPath() + ".mpk" }

// LockfilePath returns the path of the lock file
func (MessagePackBackend) LockfilePath(n MetadataNode) string { return n.InternalPath() + ".mlock" }

The xattrs_backend.go has

// IsMetaFile returns whether the given path represents a meta file
func (XattrsBackend) IsMetaFile(path string) bool { return strings.HasSuffix(path, ".meta.lock") }

// ...

// MetadataPath returns the path of the file holding the metadata for the given path
func (XattrsBackend) MetadataPath(n MetadataNode) string { return n.InternalPath() }

// LockfilePath returns the path of the lock file
func (XattrsBackend) LockfilePath(n MetadataNode) string { return n.InternalPath() + ".mlock" }

The hybrid_backend.go has

// IsMetaFile returns whether the given path represents a meta file
func (HybridBackend) IsMetaFile(path string) bool { return strings.HasSuffix(path, ".meta.lock") }

// ...

// MetadataPath returns the path of the file holding the metadata for the given path
func (b HybridBackend) MetadataPath(n MetadataNode) string {
	base := b.metadataPathFunc(n)

	return filepath.Join(base, pathify(n.GetID(), 4, 2)+".mpk")
}

// LockfilePath returns the path of the lock file
func (b HybridBackend) LockfilePath(n MetadataNode) string {
	base := b.metadataPathFunc(n)

	return filepath.Join(base, "locks", n.GetID()+".mlock")
}

IsMetaFile() is used by

1. ListRevisions in pkg/storage/fs/posix/tree/revisions.go:

   versionGlob := tp.lookup.VersionPath(n.SpaceID, n.ID, "*")
   if items, err := filepath.Glob(versionGlob); err == nil {
   	for i := range items {
   		if tp.lookup.MetadataBackend().IsMetaFile(items[i]) || strings.HasSuffix(items[i], ".mlock") {
   			continue
   		}
   

2. ListRevisions in pkg/storage/pkg/decomposedfs/tree/revisions.go:

   np := n.InternalPath()
   if items, err := filepath.Glob(np + node.RevisionIDDelimiter + "*"); err == nil {
   	for i := range items {
   		if tp.lookup.MetadataBackend().IsMetaFile(items[i]) || strings.HasSuffix(items[i], ".mlock") {
   			continue
   		}
   

And finally, these are the only occurences of .meta.lock:

❯ grep -R ".meta.lock"
grep: cmd/revad/revad: Übereinstimmungen in Binärdatei
pkg/storage/pkg/decomposedfs/metadata/xattrs_backend.go:func (XattrsBackend) IsMetaFile(path string) bool { return strings.HasSuffix(path, ".meta.lock") }
pkg/storage/pkg/decomposedfs/metadata/hybrid_backend.go:func (HybridBackend) IsMetaFile(path string) bool { return strings.HasSuffix(path, ".meta.lock") }
pkg/storage/utils/decomposedfs/metadata/xattrs_backend.go:func (XattrsBackend) IsMetaFile(path string) bool { return strings.HasSuffix(path, ".meta.lock") }

AFAICT I was involved in this in https://github.com/cs3org/reva/pull/4033/files ...

Today, I think we should fix the implementation of the IsMetaFile functions and get rid of the manual HasSuffix(items[i], ".mlock" checks.