Peter Humphrey wrote: > Hello list, > > I've created a new btrfs volume on SSDs, complete with a lot of subvolumes > corresponding to the old lvm2 logical volumes. I took the opportunity of > removing a couple of old partitions, so I now have this: > > /dev/sd[ab]1 form /dev/md1 as /boot, > /dev/sd[ab]2 are my rescue system: sda2 is its root, sdb2 is its portage tree, > /dev/sd[ab]3 is the btrfs file system. > > I can boot my rescue system with no problems, but not the main system - I get > a kernel panic with "BTRFS: failed to read the system array on sda3". I'm > writing this after chroot, su - prh, startx. > > Both in the main and rescue systems I have this: > $ grep -i btrfs /usr/src/linux/.config > CONFIG_BTRFS_FS=y > CONFIG_BTRFS_FS_POSIX_ACL=y > # CONFIG_BTRFS_FS_CHECK_INTEGRITY is not set > # CONFIG_BTRFS_FS_RUN_SANITY_TESTS is not set > # CONFIG_BTRFS_DEBUG is not set > # CONFIG_BTRFS_ASSERT is not set > > The relevant grub.cfg entries (I've moved to grub-2) are: > > menuentry 'Gentoo Linux 4.0.5, no network' { > linux /boot/kernel-x86_64-4.0.5-gentoo root=/dev/sda3 softlevel=nonet > net.ifnames=0 irqpoll > } > menuentry 'Rescue System 4.0.5' { > linux /boot/kernel-x86_64-4.0.5-gentoo-rescue root=/dev/sda2 > net.ifnames=0 irqpoll > } > > Something seemed to be wrong in the kernel setup, so to test that I compiled > the main kernel with the .config from the rescue system. Same result. > > Another test: I wondered whether, somehow, the btrfs volume included the name > of the mount point where it had been created, and would only allow itself to > be mounted there. Not so: moving its mount point in the rescue system didn't > prevent it from being mounted. I didn't expect it would, since the kernel > panic occurs long before fstab is read. > > The other thing I've tried is to build an initramfs with dracut. I tried to > include its btrfs module but it refused because it couldn't find a command > btrfs. So I recompiled the kernel with btrfs as a module and added > 'filesystems+="btrfs" ' into dracut.conf. Still no success. > > After a few days of floundering around, copious googling and getting splinters > under my fingernails I'm out of ideas. Can anyone see what else I can try? I > created the btrfs with "mkfs.btrfs -m raid1 -d raid1 --label GENTOO /dev/sda3 > /dev/sdb3". I've done that twice, with all the subvolume creation and backup > recovery, the second time with --force. >
This may not be related but thought I would mention. For some reason, my system will not boot a kernel newer than 3.18.7. I use gentoo-sources and generally use make oldconfig. I have also tried the new 4.0 kernels as well. They try to boot but don't make it past the kernel trying to do its thing. I don't reboot often so I have not had the chance to figure out exactly why this is happening. Recently I had to start using that pesky init thingy but I don't think that is causing the problem. I get a error/panic and then it says it is going to reboot in 10 seconds. By the time I figure out where the failure might be, it reboots itself. I thought I would mention just in the rare event you are running into the same issue I am. Just a thought. If you know this isn't the problem, just ignore and carry on. Dale :-) :-)