Excerpts from Vladi Gergov's message of 2010-10-29 16:53:42 -0400: > >>> gypsyops @ /mnt > sudo mount -o degraded /dev/sdc das3/ > Password: > mount: wrong fs type, bad option, bad superblock on /dev/sdc, > missing codepage or helper program, or other error > In some cases useful info is found in syslog - try > dmesg | tail or so > > [ 684.577540] device label das4 devid 2 transid 107954 /dev/sdc > [ 684.595150] btrfs: allowing degraded mounts > [ 684.595594] btrfs: failed to read chunk root on sdb > [ 684.604110] btrfs: open_ctree failed > > >>> gypsyops @ /mnt > sudo btrfsck /dev/sdc > btrfsck: volumes.c:1367: btrfs_read_sys_array: Assertion `!(ret)' failed.
Ok, I dug through this and found the bug responsible for your unmountable FS. When we're mounted in degraded mode, and we don't have enough drives available to do raid1,10, we're can use the wrong raid level for new allocations. I'm fixing the kernel side so this doesn't happen anymore, but I'll need to rebuild the chunk tree (and probably a few others) off your good disk to fix things. I've got it reproduced here though, so I'll make an fsck that can scan for the correct trees and fix it for you. Since you're basically going to be my first external fsck customer, is there anyway you can do a raw device based backup of the blocks? This way if I do mess things up we can repeat the experiment. -chris -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
