Package: dpkg Version: 1.18.10 Severity: normal Hi,
overlayfs does not support renaming directories when the directories live in the lower filesystem: * Directory renames only allowed on "pure upper" (already created on * upper filesystem, never copied up). Directories which are on lower or * are merged may not be renamed. For these -EXDEV is returned and * userspace has to deal with it. This means, when copying up a * directory we can rely on it and ancestors being stable. https://github.com/torvalds/linux/blob/v4.8-rc2/fs/overlayfs/copy_up.c#L318-L322 Unfortunately this means that dpkg fails at least in the case where a directory is converted into a file: apt 1.3~rc2 moves /usr/share/bug/apt/script to /usr/share/bug/apt . This causes dpkg to fail when running in an overlayfs with the following error: # dpkg -i /var/cache/apt/archives/apt_1.3~rc3_amd64.deb (Reading database ... 11401 files and directories currently installed.) Preparing to unpack .../archives/apt_1.3~rc3_amd64.deb ... Unpacking apt (1.3~rc3) over (1.3~rc2) ... dpkg: error processing archive /var/cache/apt/archives/apt_1.3~rc3_amd64.deb (--install): unable to move aside './usr/share/bug/apt' to install new version: Invalid cross-device link dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Processing triggers for libc-bin (2.23-5) ... Errors were encountered while processing: /var/cache/apt/archives/apt_1.3~rc3_amd64.deb I don't know what the correct workaround should be. This can break pre-build upgrades in sbuild when the schroot is of overlayfs type. -- System Information: Debian Release: stretch/sid APT prefers unstable-debug APT policy: (500, 'unstable-debug'), (500, 'unstable'), (1, 'experimental-debug'), (1, 'experimental') Architecture: amd64 (x86_64) Foreign Architectures: i386 Kernel: Linux 4.6.0-1-amd64 (SMP w/4 CPU cores) Locale: LANG=en_GB.utf8, LC_CTYPE=en_GB.utf8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Init: systemd (via /run/systemd/system) Versions of packages dpkg depends on: ii libbz2-1.0 1.0.6-8 ii libc6 2.23-5 ii liblzma5 5.1.1alpha+20120614-2.1 ii libselinux1 2.5-3 ii tar 1.29b-1 ii zlib1g 1:1.2.8.dfsg-2+b1 dpkg recommends no packages. Versions of packages dpkg suggests: ii apt 1.3~rc3 -- no debconf information
