[20.10 backport] containerd fixes for BuildKit #2

Merged

thaJeztah merged 3 commits intomoby:docker/20.10from thaJeztah:20.10_backport_buildkit_fixes

Sep 1, 2022

+129-7

Commits on Aug 30, 2022

Adjust overlay tests to expect "index=off"

estesp
authored and
thaJeztah
committed
overlay: support "userxattr" option (kernel 5.11)

AkihiroSuda
authored and
thaJeztah
committed
docker: avoid concurrent map access panic

tonistiigi
authored and
thaJeztah
committed