Re: panic: ffs_snapshot_mount: already on list

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

> On 2. Oct 2018, at 12:23, Manuel Bouyer <bouyer%antioche.eu.org@localhost> wrote:
> 
> On Tue, Oct 02, 2018 at 12:11:49PM +0200, J. Hannken-Illjes wrote:
>> 
>>> On 18. Sep 2018, at 16:39, J. Hannken-Illjes <hannken%eis.cs.tu-bs.de@localhost> wrote:
>>> 
>>> 
>>>> On 18. Sep 2018, at 16:33, Manuel Bouyer <bouyer%antioche.eu.org@localhost> wrote:
>>>> 
>>>> On Tue, Sep 18, 2018 at 04:24:28PM +0200, J. Hannken-Illjes wrote:
>>>>> There will be no copy-on-write to persistent snapshots so the snapshots
>>>>> will contain garbage where the real file system writes data.
>>>> 
>>>> Ha yes, of course. One could argue that if a systadmin boots a
>>>> kernel with FFS_NO_SNAPSHOT he should know what he's doing.
>>>> 
>>>> Maybe we could leave out the FFS_NO_SNAPSHOT change, and just clear the
>>>> extra fs_snapinum[] entry ?
>>> 
>>> 
>>> Without looking further I would suggest to print a warning, print the
>>> fs_snapinum list and clear the entry as this inode is already an
>>> active snapshot.
>> 
>> This will not work as we must remove the first duplicate which
>> is already active.
> 
> So maybe we could just print a warning and ignore the duplicates at mount
> time ? Are shapshots checked on a read-only mount ?

A warning is not sufficient as we may be using the wrong block hints list.

Snapshots are checked on read-write mounts only.

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