Re: FreeBSD 5.2.1-RC2 fs snapshot problems.

Don Lewis wrote:
> On 16 Feb, Joseph Scott wrote:
> 
>>	I just finished testing a fresh install of FreeBSD 5.2.1-RC2 and
>>have verified that the problem mentioned in PR kern/58154 is still there.
>>The problem is fairly simple to show:
>>
>>1.  Install a fresh 5.2.1-RC2 system.
>>2.  Shutdown a few times to show that it completes correctly.
>>3.  Create some snapshots of a filesystem (on 5.2.1-RC2 I did
>>    3 snapshots of /usr).
>>4.  Try to shutdown again.
>>5.  Watch your system hang forever, unable to complete a shutdown
>>    correctly.
>>
>>	I've done this samething on 3 different systems with the exact
>>same results every single time.  If you cycle the power to reboot and then
>>delete the snapshot files shutdown is able to work completely once more.
>>
>>	I'm more than willing to try out patches or different
>>settings/options in an effort to try and track this down.  I would be
>>thrilled to be able to use fs snapshots for systems at work, but as it
>>stands not being able to shutdown a system makes the snapshot feature
>>useless.
>>
>>	Sorry about cross posting this so much, but I've been trying to
>>raise the attention level of this problem for weeks now without any luck.
> 
> 
> I saw this as well a couple of months ago.  I think I was running
> 5.2-CURRENT.
> 

There are fundamental issues with FFS snapshots and our buffer/cache
that are well beyond the scope of fixing for 5.2.1.  If someone has an
idea of how to fix them for 5.3, all the better.

Scott