Ubuntu kernel supports overlayfs in user namespaces.
However, Docker had previously crafting overlay opaques directly
using mknod(2) and setxattr(2), which are not supported in userns.
Tested with LXD, Ubuntu 18.04, kernel 4.15.0-36-generic #39-Ubuntu.
Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
Changes most references of syscall to golang.org/x/sys/
Ones aren't changes include, Errno, Signal and SysProcAttr
as they haven't been implemented in /x/sys/.
Signed-off-by: Christopher Jones <tophj@linux.vnet.ibm.com>
[s390x] switch utsname from unsigned to signed
per 33267e036f
char in s390x in the /x/sys/unix package is now signed, so
change the buildtags
Signed-off-by: Christopher Jones <tophj@linux.vnet.ibm.com>
When converting an opaque directory always keep the original
directory tar entry to ensure directory is created with correct
permissions on restore.
Closes#27298
Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
Currently when overlay creates a whiteout file then the overlay2 layer is archived,
the correct tar header will be created for the whiteout file, but the tar logic will then attempt to open the file causing a failure.
When tar encounters such failures the file is skipped and excluded for the archive, causing the whiteout to be ignored.
By skipping the copy of empty files, no open attempt will be made on whiteout files.
Fixes#23863
Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
