DiskFileSystem carries serializable fields (name, root,
denied_paths) inside DiskFileSystemInner alongside session-scoped
state (the notify watcher, invalidator maps, weak TurboTasksApi,
etc.) This is important to maintain invariants in a session and ensure invalidations work, so we
never evict this data.
Errors that can occur when resolving a path with symlinks.
Many of these can be transient conditions that might happen when package managers are running.