Please do test the work-around. If indeed NFSv4 solves your overlayfs problem then that would be another reason for fixing nfsmount.
We can carry Ubuntu specific fixes if for some reason Debian doesn't want them but the preferred way is obviously to fix it in Debian so that it tickles down naturally to Ubuntu (and other Debian based distros).
I'm looking at it atm but NFS is not my strong suit :-)
Please do test the work-around. If indeed NFSv4 solves your overlayfs problem then that would be another reason for fixing nfsmount.
We can carry Ubuntu specific fixes if for some reason Debian doesn't want them but the preferred way is obviously to fix it in Debian so that it tickles down naturally to Ubuntu (and other Debian based distros).
I'm looking at it atm but NFS is not my strong suit :-)