Recurring problem: processes block accessing UFS file system

[Kris Kennaway]

On Mon, Nov 21, 2005 at 09:23:10PM -0600, Greg Rivers wrote:
> On Mon, 21 Nov 2005, Kris Kennaway wrote:
> 
> >Looks like a UFS snapshot deadlock.  Are you running something like dump 
> >-L on this filesystem, or making other use of snapshots?
> >
> 
> Indeed I am (dump -L), but as I said (not very clearly, sorry), the 
> deadlock also occurs under normal operation when no snapshots are running 
> or have ever been run since boot.  It's just much less frequent in this 
> case.  Disabling dumps altogether was one of the first things I tried.

It may not be the same problem.  You should also try to obtain a trace
when snapshots are not implicated.

'show lockedvnods' is very important for diagnosing filesystem
deadlocks, and 'alltrace' is the easiest way to obtain stack traces
for the resulting processes that are holding locks.  You'll want to
'set $lines=0' and capture the output from the serial console to a
file.

Kris
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