5e0d1fa18e
On systems that supports reflinking (i.e. btrfs) this means the dummy backend is much faster at copying files and will be sharing file data in a CoW fashion. On my (btrfs) system this makes "docker run ubuntu echo hello world" go from about 3 seconds to about 1 second. Not instant, but clearly better. cp --reflink=auto is availible since coreutils 7.5 (around 2009), so this seems pretty ok to rely on. cp is also better at preserving file metadata than tar, so for instance it will copy xattrs. Upstream-commit: 242fd4b3ef32b5a20135d6031040bcf099b5df4e Component: engine