** Changed in: linux (Ubuntu Disco) Status: In Progress => Fix Committed
** Changed in: linux (Ubuntu Eoan) Status: In Progress => Fix Committed -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1846272 Title: overlayfs: allow with shiftfs as underlay Status in linux package in Ubuntu: Fix Committed Status in linux source package in Disco: Fix Committed Status in linux source package in Eoan: Fix Committed Bug description: SRU Justification Impact: Currently it is not possible to use overlayfs on top of shiftfs. This means Docker inside of LXD cannot make user of the overlay2 graph driver which is blocking users such as Travis from making use of it efficiently. Regression Potential: Limited to shiftfs and overlayfs on top of shiftfs. Overlayfs does prevent "remote" filesystems such as ceph, nfs, etc. from being used as the underlay. With this patch shiftfs however can be used as an underlay and we special case it as a suitable filesystem to be used under overlayfs. I verified that the patch does not lead to regression on overlayfs workloads that do not make use of shiftfs as underlay. Additionally, I tested Docker with the overlay2 graphdriver on top of shiftfs. This also has not lead to any regressions. Test case: Building a kernel with the patch: sudo snap install lxd sudo lxd init sudo lxc launch images:ubuntu/bionic b1 sudo lxc config set b1 security.nesting true sudo lxc restart --force b1 sudo lxc shell b1 sudo apt-get install \ apt-transport-https \ ca-certificates \ curl \ gnupg-agent \ software-properties-common curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add - curl -fsSL get.docker.com | CHANNEL=test sh sudo add-apt-repository \ "deb [arch=amd64] https://download.docker.com/linux/ubuntu \ $(lsb_release -cs) \ stable" sudo apt-get update sudo apt-get install docker-ce docker-ce-cli containerd.io sudo systemctl stop docker cat <<EOF /etc/docker/daemon.json { "storage-driver": "overlay2" } EOF sudo systemctl start docker docker run -it ubuntu bash and observe that it works. The old approach we used in https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1838677 caused a regression. The reproducer for this regression appended in https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1842382/comments/45 did show that the regression cannot be reproduced with the new patch. Target kernels: All LTS kernels that do support shiftfs, if possible. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1846272/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp