'bad tree block start' mount failure...

'bad tree block start' mount failure...

[Daniel J Blueman]

Booting linux 3.3, I found a particular set of steps [1] produces an
fs which is unmountable [2]. This also occurs when data is written
after mounting, so is entirely possible to hit in practice if RAID-0
is used.

Many thanks,
  Daniel

--- [1]

mkfs.btrfs -m raid0 -d raid0 /dev/sdb1 /dev/sdc1
mount /dev/sdb1 /mnt
umount /mnt
mount /dev/sdb1 /mnt -o compress
umount /mnt
mount /dev/sdb1 /mnt -o ssd
umount /mnt
mount /dev/sdb1 /mnt -o discard
umount /mnt
mount /dev/sdb1 /mnt
<mount failure>

--- [2]

[13259.593809] btrfs bad tree block start 0 37715968
[13259.593832] btrfs: failed to read tree root on sdc1
[13259.594221] btrfs: open_ctree failed
-- 
Daniel J Blueman

Re: 'bad tree block start' mount failure...

[Andrea Gelmini]

2012/3/20 Daniel J Blueman <daniel@quora.org>:
> mkfs.btrfs -m raid0 -d raid0 /dev/sdb1 /dev/sdc1
> mount /dev/sdb1 /mnt
> umount /mnt
> mount /dev/sdb1 /mnt -o compress
> umount /mnt
> mount /dev/sdb1 /mnt -o ssd
> umount /mnt
> mount /dev/sdb1 /mnt -o discard
> umount /mnt
> mount /dev/sdb1 /mnt
> <mount failure>

Well, I can't reproduce this. It's also true that I use some
out-of-the-tree patches.
I wrote this each step. They must be in a script?

Ciao,
Gelma

Re: 'bad tree block start' mount failure...

[Daniel J Blueman]

On 21 March 2012 00:16, Andrea Gelmini <andrea.gelmini@gmail.com> wrote:
> 2012/3/20 Daniel J Blueman <daniel@quora.org>:
>> mkfs.btrfs -m raid0 -d raid0 /dev/sdb1 /dev/sdc1
>> mount /dev/sdb1 /mnt
>> umount /mnt
>> mount /dev/sdb1 /mnt -o compress
>> umount /mnt
>> mount /dev/sdb1 /mnt -o ssd
>> umount /mnt
>> mount /dev/sdb1 /mnt -o discard
>> umount /mnt
>> mount /dev/sdb1 /mnt
>> <mount failure>
>
> Well, I can't reproduce this. It's also true that I use some
> out-of-the-tree patches.
> I wrote this each step. They must be in a script?

I can reproduce this booting with the ubuntu 3.3 mainline kernel with
eg 'ramdisk_size=2048000' and then:

# mkfs.btrfs -m raid0 -d raid0 /dev/ram0 /dev/ram1
# mount /dev/ram0 /mnt
# umount /mnt
# mount /dev/ram0 /mnt -o compress
# umount /mnt
# mount /dev/ram0 /mnt -o ssd
# umount /mnt
# mount /dev/ram0 /mnt -o discard
# umount /mnt
# mount /dev/ram0 /mnt
mount: wrong fs type, bad option, bad superblock on /dev/ram0,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

Thanks,
  Daniel
-- 
Daniel J Blueman