Hi, I had some difficulty getting an md-raid1 / bcache / lvm stack to boot up succesfully on the recent debian wheezy-backports 3.16-0.bpo.2-amd64 kernel with the rootfs on bcache (and a separate /boot). I ended up having to patch two parts of the initramfs to get it working. The bcache-tools patch is probably not the correct solution, but I'm not sure what the exact issue is which causes bcache-register to fail for a newly added md device.. 1) In bcache-tools, the /dev/md0 udev rule to invoke /lib/udev/bcache-register /dev/md0 has some timing constraint; namely, during initramfs bootup the echo "$1" > /sys/fs/bcache/register_quiet part seems to give (based on udev_log="debug" output): write error: Invalid arument without any additional info in dmesg. However, running the identical command: /lib/udev/bcache-register /dev/md0 by hand a short while later from within the initramfs prompts works.. I modified bcache-register to include include a sleep, and now the /dev/bcache0 device registers during boot. 2) This exposes a related bug within the mdadm initramfs scripts, as per https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=644876#85 So the mdadm part of local-top has to wait for udev to settle and the /dev/bcache0 devices to show up before attempting to activate the lvm VGs. Not a bcache issues, but part of the workaround... -- Tero Marttila --- bcache-tools-1.0.7/bcache-register 2014-05-10 16:38:21.000000000 +0300 +++ /lib/udev/bcache-register 2014-10-11 18:27:42.641482307 +0300 @@ -1,4 +1,7 @@ #!/bin/sh /sbin/modprobe -qba bcache + +echo "$0 sleeping for $1 to settle, while we have:" /dev/bcache* >&2; sleep 5 + test -f /sys/fs/bcache/register_quiet && echo "$1" > /sys/fs/bcache/register_quiet --- mdadm-3.2.5/debian/initramfs/script.local-top 2012-08-25 22:29:05.000000000 +0300 +++ /usr/share/initramfs-tools/scripts/local-top/mdadm 2014-10-11 18:15:23.804520521 +0300 @@ -97,11 +97,8 @@ done fi -if [ -x "$(command -v udevsettle)" ]; then - verbose && log_begin_msg "Waiting for udev to process events" - udevsettle 10 - verbose && log_end_msg -fi +# XXX: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=644876 +wait_for_udev 10 maybe_break post-mdadm -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
