On Fri, Aug 21, 2015 at 9:23 PM, Neal Gompa <ngompa@xxxxxxxxxxxxxxxxx> wrote: > Hello, > > For those who have received this message twice already, I sincerely apologize. > > Yesterday I filed an issue in the CentOS bug tracker (#9297[1]) and > the Red Hat Bugzilla (#1255512[2]) about OverlayFS with Btrfs as the > upper layer. > > The issue was discovered by a colleague of mine, and we verified the > issue exists in the EL7 kernel and mainline kernels (tested on Arch > Linux). I additionally verified the problem exists in Fedora kernels. > > Rather than quoting the issue, I'll just note that the issue is > described quite well in the filed bugs noted earlier. In the linked > bugs, there's a simple Bash script that will reliably reproduce the > problem. While the script uses tmpfs at the lower layer, we originally > discovered the problem with ext4 as the lower layer and verified that > it doesn't matter which lower layer filesystem it is, the problem > exists. Additionally, the problem doesn't exist when using ext4 as the > upper layer. > > I was advised by Josh Boyer to email you guys (and the mailing lists, > to be sure to get everyone a chance to look over it) about the > problem, since it affects mainline. > > [1]: https://bugs.centos.org/view.php?id=9297 > [2]: https://bugzilla.redhat.com/show_bug.cgi?id=1255512 AFAICS btrfs doesn't support RENAME_EXCHANGE and RENAME_WHITEOUT. These flags are needed for any filesystem that wants to be a fully functional overlayfs upper layer. Thanks, Miklos -- To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
