Re: can't read superblock (but could mount)
From: Chris Mason <hidden>
Date: 2012-02-10 22:18:42
On Fri, Feb 10, 2012 at 08:30:51PM +0100, btrfs@nentwig.biz wrote:
Hi! I used to have arch linux running on 1 btrfs partition (sda1, incl. /boot). When switching to 3.2.5 recently the system fails to boot: (after udevd) /etc/rc.sysinit: line 15: 117 Bus error mountpoint -q /proc and so on, no idea. It used to boot with 3.2.4, but 1) I obviously had some corruption in the tree, when I tried to delete a certain file I hit e.g. "kernel BUG at fs/btrfs/extent-tree.c" message. 2) Even while running 3.2.4 I was unable to mount the partition from a parallel gentoo or live USB install and I still am: # mount /dev/sda1 /mnt/arch/ mount: /dev/sda1: can't read superblock The strange thing is: when trying to boot from the partition the boot loader (syslinux) is obviously still able load the kernel from that partition. Tried btrfs-zero-log and some deperate other things. Result: I can now actually execute btrfsck which previously used to fail:
Ok, step one: Pull down the dangerdonteveruse branch of btrfs-progs: git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-progs.git dangerdonteveruse Run btrfs-debug-tree -r /dev/sda1 and send the output here please. This block with bad transid is from your FS root. We'll need to a root that matches. But we should be able to patch things up! -chris