Package: cloud.debian.org Severity: important The ext4 filesystem for at least the libvirt box on Atlas is too new for the version of e2fsprogs in jessie.
Trying to label the root partition results in: tune2fs 1.42.12 (29-Aug-2014) tune2fs: Filesystem has unsupported read-only feature(s) while trying to open /dev/vda1 Couldn't find valid filesystem superblock. Probable cause is an unsupported feature: # dumpe2fs -h /dev/vda1 | grep -i feature dumpe2fs 1.42.12 (29-Aug-2014) Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent 64bit flex_bg sparse_super large_file huge_file dir_nlink extra_isize metadata_csum Journal features: journal_incompat_revoke journal_64bit FEATURE_I4 FEATURE_I4 is "journal_checksum_v3" which is probably set by the hosts mkfs.ext4, but since the jessie e2fsprogs don't support it, it should not be set. It may even be the case that fsck will fail but I have not tested this. To avoid this, "mkfs.ext4 -O ^metadata_csum" should suffice, until e2fsprogs is at 1.43 or higher in jessie..