Re: Mysterious device (id 0).

[Anand Jain <anand.jain@oracle.com>]

On 05/16/2015 12:37 AM, Christian wrote:
> On 05/15/2015 12:20 PM, Anand Jain wrote:
>>
>>
>> On 05/15/2015 08:09 AM, Christian wrote:
>>> Hi,
>>>
>>> My laptop has a small ext4 /boot partition /dev/sda1 and a large btrfs
>>> partition containing / and /home as a sub volume /dev/sda3
>>>
>>> When I run scrub on /dev/sda3 and check status with sudo btrfs scrub
>>> status -d /dev/sda3 I get:
>>>
>>> scrub status for 3d52dc93-c89f-453f-965d-8601d11e7710
>>> scrub device /dev/sda3 (id 1) history
>>>      scrub started at Thu May 14 19:54:02 2015 and finished after 235
>>> seconds
>>>      total bytes scrubbed: 111.03GiB with 0 errors
>>> scrub device  (id 0) history
>>>      scrub started at Thu May 14 19:54:02 2015 and was aborted after 0
>>> seconds
>>>      total bytes scrubbed: 0.00B with 0 errors
>>
>>   we are reading an uninitialized device struct and that uninitialized
>>   devid happens to be 0. looks like num_devices count went haywire.
>>
>>   in this config was there any device delete ? or a reduce in # of
>>   devices? and has the system been rebooted after that ?
>>
>> Thanks, Anand
>
> Not sure I understand fully what you are asking, but I deleted a swap
> partition on the drive a while back and increased the size of the btrfs
> partition (with gparted). I have rebooted many times since then. That is
> all the changes I have done to this SSD recently.

  ok got it. now do you have any other disk in the system with the same
  fsid ? what does the btrfs fi show -d or blkid show.

Thanks


> Thanks.
>>
>>
>>> As device (id 0) is indicated, but I have no idea what it is.
>>>
>>> When I run scrub with a script (cron) the same device (id 0) shows up in
>>> a warning:
>>>
>>> /etc/cron.daily/btrfs-scrub:
>>> WARNING: device 0 not present
>>> scrub device /dev/sda3 (id 1) done
>>>      scrub started at Sat May  2 08:03:46 2015 and finished after 241
>>> seconds
>>>      total bytes scrubbed: 109.06GiB with 0 errors
>>> scrub device  (id 0) canceled
>>>      scrub started at Sat May  2 08:03:46 2015 and was aborted after 0
>>> seconds
>>>      total bytes scrubbed: 0.00B with 0 errors
>>>
>>> What is this device (id 0) which never gets scrubbed but always shows
>>> up?
>>>
>>> I'm running Ubuntu 15.04 with the 3.19.0-16-generic kernel.
>>>
>>> P.S. I am not a developer.
>>>
>> --
>
>
>