Comment 0 for bug 1480411

rm -r * fails to delete directories when using overlayfs in a user-namespace.

If overlayfs is mounted as follows,

   mount -n -t overlay overlay -o lowerdir=lowerdir,upperdir=upperdir,workdir=workdir mntpt

and if lowerdir contains lowerdir/foo/bar.txt, then,

   rm -r mntpt/foo

fails with error message,

   "rm: cannot remove ‘mntpt/foo’: Operation not permitted"

strace shows,

    unlinkat(AT_FDCWD, "mntpt/foo", AT_REMOVEDIR) = -1 EPERM (Operation not permitted)

OS details: 64-bit ubuntu 14.04.2 with the linux-generic-lts-vivid kernel.

The bug does not occur with the default 3.13 kernel. The bug occurs for any vanilla 3.18+ kernel to which the 1-line patch, "overlayfs: allow unprivileged mounts" is added. (The patch is at, http://kernel.ubuntu.com/git/ubuntu/ubuntu-vivid.git/commit/?id=78ec45495b15d27d4cc6d05cc454e30ec5b587ea)

The bug occurs regardless of whether the underlying filesystem is tmpfs or ext4.

A script which reproduces the bug is attached and is also available at http://paste.ubuntu.com/11974137/

Hardware: intel core2 duo processor in a macbook-4.1