Re: snapshot_mount: already on list

["J. Hannken-Illjes" <hannken%eis.cs.tu-bs.de@localhost>]

> On 23. Nov 2018, at 11:57, Emmanuel Dreyfus <manu%netbsd.org@localhost> wrote:
> 
> Hello
> 
> Some times ago, I encountered this nasty bug where the kernel
> would crash when mounting a filesystem with snapshots. I thought
> it was fixed, but it seems there are some problems leftover, at least
> on netbsd-8. 
> 
> The crash:
> 
> /mail: replaying log to disk
> ffs_snapshot_mount: vget failed 2
> panic: ffs_snapshot_mount: 211471882 already on list

This error cannot be fixed in the kernel as we had to remove
the first inode from the list and when we detect this situation
it is too late.

Running fsck on the file system should remove duplicates from
the list of snapshots to mount.

> After another reboot, I ran fsck on the fileystem, inode 211471882
> indeed as troubles:
> 
> ** Phase 1 - Check Blocks and Sizes
> INCORRECT BLOCK COUNT I=211471881 (31466368 should be 31466624)
> CORRECT? yes
> 
> 845563840 DUP I=211471882
> 845563841 DUP I=211471882
> 845563842 DUP I=211471882
> 845563843 DUP I=211471882
> 845563844 DUP I=211471882
> 845563845 DUP I=211471882
> 845563846 DUP I=211471882
> 845563847 DUP I=211471882
> INCORRECT BLOCK COUNT I=211471882 (11141696 should be 11142208)
> CORRECT? yes

Did the file system mount OK after fsck?

--
J. Hannken-Illjes - hannken%eis.cs.tu-bs.de@localhost - TU Braunschweig (Germany)