Re: 5.4.20: cannot mount device that blipped off the bus: duplicate device fsid:devid for

[Marc MERLIN <marc@merlins.org>]

On Thu, Mar 26, 2020 at 11:33:23AM +0800, Anand Jain wrote:
>  We would log the below only if the old device sde is still in mounted
>  state.  Unfortunately we don't have the unmount event log yet (patches
>  are in the ML) so we don't know if unmount was successful.
> 
> [2560416.434529] BTRFS warning (device sde1): duplicate device fsid:devid
> for 727c7ba3-f6f9-462a-8472-453dd7d46d8a:1 old:/dev/sde1 new:/dev/sdq1
> 
>  If the device is unmounted, the scan would have replaced the sde
>  to sdi, unless the sde (stale) generation is > generation in sdi
>  (lost commit). In which case the --forget is useful to remove the
>  state device entry (provided device is unmounted).
 
Well, the device did disappear, wouldn't that cause the in memory
version to be more recent than the disk version?

>  Its strange /proc/mounts doesn't list sde. Could you please send me
>  complete kernel logs. Lets try if there is any clue.
 
Sure https://pastebin.com/SWAfYxV8
 
>  I tried to reproduce.. but in my case the unmount was successful.
> 
> 
> $ mkfs.btrfs -fq /dev/sdc && mount /dev/sdc /btrfs
> $ devmgt show | grep sdc
> host2 sdc
> $ devmgt detach /dev/sdc
> ::
> detach /dev/sdc successful
> $ devmgt attach host2

That's probably too clean.
Can you 
1) write to device in a loop
2) pull power from SATA device (in this case it was an ssd)
3) plug device back in

> $ umount /dev/sdc
> 
> Unfortunately there is no log about the unmount :-(.

Maybe worth adding to help debug later?

I looked in my bash history, and it shows this:
37280  mount | grep sde
37281  umount /mnt/btrfs_space
37282  umount /var/local/space
37283  umount /var/cache/zoneminder
37284  fuser -vm /var/cache/zoneminder
37285  fuser -vkm /var/cache/zoneminder
37286  umount /var/cache/zoneminder
37287  umount /var/lib/mysql
37288  mount | grep sde1

First time, I got output to the mount command.
Second time I did not.

other commands I typed:
37289  mount /dev/sdq1 /mnt/btrfs_space
37296  btrfs device scan
37301  grep sde /etc/* 2>/dev/null
37303  mount /dev/sdq1 /mnt/btrfs_space
37308  grep -r /mnt/btrfs_space /etc 2>/dev/null
37311  btrfs device scan 
37312  l /sys/block/sde/
37313  btrfs check /dev/sdq1
37314  btrfs device scan 
37320  mount /dev/sdq1 /mnt/mnt
37323  btrfs device scan
37324  dmesg |tail -1
37326  lsblk -v
37327  lsblk 
37328  grep sde /proc/mounts 

Hope this helps.

Marc
-- 
"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
 
Home page: http://marc.merlins.org/