The ubuntu-core-rootfs script in initial ramdsik initrd.img-3.19.0-16-generic report panic “cannot find writable partition”
Because the script only wait for %root% partition and /dev/sda5 partition is not ready.
I have added following code to the script, to confirm it’s a timing issue.
echo $(ls /dev/disk/by-label) >/dev/kmsg || true
path=$(get_partition_from_label "$writable_label")
[ -n "$path" ] || sleep 3
[ -n "$path" ] ||echo "retry wait 3 seconds" >/dev/kmsg || true
[ -n "$path" ] || path=$(get_partition_from_label "$writable_label")
[ -n "$path" ] || panic "cannot find '$writable_label' partition"
Logs,
[ 13.047190] initrd: mounting /dev/sda3
[ 13.050213] EXT4-fs (sda3): couldn't mount as ext3 due to feature incompatibilities
[ 13.053662] EXT4-fs (sda3): couldn't mount as ext2 due to feature incompatibilities
[ 13.192459] EXT4-fs (sda3): mounted filesystem with ordered data mode. Opts: (null)
[ 13.196587] initrd: mounting /run
[ 13.201201] Temporary\x20Storage system-a system-boot don’t have ‘writable ‘
[ 16.208151] retry wait 3 seconds
[ 16.221709] initrd: checking filesystem for writable partition
[ 16.231462] random: nonblocking pool is initialized
[ 16.235143] EXT4-fs (sda5): couldn't mount as ext3 due to feature incompatibilities => after 3 seconds writable partition sda5 was discovered
In speaking with rsalveti, it looks like the cause here is rootdelay=X is not respected for the writable partition.