On 2013-02-14, at 16:24 , Rick Macklem <rmack...@uoguelph.ca> wrote:
> Marc Fournier wrote:
>> On 2013-02-14, at 08:41 , Rick Macklem <rmack...@uoguelph.ca> wrote:
>>
>>>
>>> Btw Marc, if you just want this problem to go away, I suspect
>>> getting rid
>>> of the "intr" mount option would do that.
>>
>> Am more interested in fixing the problem (if possible) then just
>> masking it, but ...
>>
>> Based on the man page for mount_nfs, wouldn't that have the opposite
>> effect:
>>
>> intr Make the mount interruptible, which implies that file
>> system calls that are delayed due to an unresponsive
>> server will fail with EINTR when a termination signal is
>> posted for the process.
>>
>> I may be mis-reading, but from the above it sounds like a -9 *should*
>> terminate the process if intr is enabled, while with it disabled, it
>> would ignore it … ?
>>
> Yes, you have misread it (or english is a wonderfully ambiguous thing,
> if you prefer;-).
>
> For hard mounts (which is what you get if you don't specify either "soft"
> nor "intr"), the RPCs behave like other I/O subsystems, which means they
> do non-interruptible sleeps ("D" stat in ps) waiting for server replies
> and continue to try and complete the RPC "forever". You can't kill off
> the process/thread with any signal.
>
> If "umount -f" of the filesystem works, that terminates the thread(s).
> Unfortunately, "umount -f" is quite broken again. I have an idea on
> how to resolve this, but I haven't coded it yet. (The problem is that
> the process doing "umount -f" gets stuck before it does the VFS_UNMOUNT(),
> so the NFS client doesn't see it.)
For how infrequently this problem generally manifests itself, is there an
overall benefit from a debugging standpoint of my leaving intr on and
reporting when it happens, including procstat output, and then upgrading to
latest kernel … ?
Its an annoyance, but it isn't like it happens daily, so I don't mind going
through the process *towards* having it fixed if there is an overall benefit …
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