Previously, graphdriver/copy would improperly copy hardlinks as just regular
files. This patch changes that behaviour, and instead the code now keeps
track of inode numbers, and if it sees the same inode number again
during the copy loop, it hardlinks it, instead of copying it.
Signed-off-by: Sargun Dhillon <sargun@sargun.me>
Upstream-commit: b467f8b2ef21dc2239dcd136a29283ea6c3a0aee
Component: engine