processes stuck on a vnode lock

[Andriy Gapon]

on 04/11/2010 16:45 Andriy Gapon said the following:
> on 04/11/2010 09:49 Andriy Gapon said the following:
>>
>> I see a few processes stuck on the same vnode, trying to take or to upgrade to
>> an exclusive lock on it, while the lock data suggests that it is already
>> shared-locked.  The vnode is a root vnode of one of ZFS filesystems (it's not a
>> global root).
>>
>> I couldn't find any (other) threads that could actually hold the vnode lock, but
>> lock shared count is suspiciously or coincidentally the same as number of
>> threads in zfs_root call.
> 
> BTW, I still have the system alive and online, so if anyone has ideas I can try them.
> 

The kernel is not live now, but I have saved it and vmcore of the system.

Kostik,

just a pure guesswork here - could r214049 have something to do with this?
I looked at the change and it looks completely correct - I don't think that a
vnode lock can be leaked by that code.  But, OTOH, it has some special handling
for VV_ROOT, it's in NFS code and and it's in a right time-frame, so just asking.

Here's a link to the start of this report thread:
http://thread.gmane.org/gmane.os.freebsd.devel.file-systems/10659/focus=128893

-- 
Andriy Gapon