Re: Processes stuck in D state when accessing XFSv5 filesystem

Brian Foster
2017-04-07T17:39:49Z

On Fri, Apr 07, 2017 at 12:56:48PM -0400, David Shaw wrote:
> On Apr 7, 2017, at 10:56 AM, Emmanuel Florac <eflorac@intellique.com> wrote:
> >
> > Le Thu, 6 Apr 2017 14:41:45 -0400
> > David Shaw <dshaw@jabberwocky.com> écrivait:
> >
> >> I'm having a problem with processes getting "stuck" when accessing an
> >> XFS (v5) filesystem. When it happens, I start getting the "blocked
> >> for more than 120 seconds" error, and the process stays in that state
> >> until I reboot. The kernel is 3.10.0-514.2.2 and the xfsprogs is
> >> 4.5.0-9 (both Centos 7.3).
> >>
> >
> > Could it be that your system is under high IO load?
>
> It's possible that the problem is instigated or made worse by high load, but once the processes enter D state, they stay there even when the system is idle. They stay in D state until I reboot.
>

There isn't enough information provided to suggest the filesystem is
locked up as opposed to waiting for (very slow) I/O, as suggested by
Emmanuel.

If the filesystem appears to be deadlocked, can you provide the complete
hung task output (echo w > /proc/sysrq-trigger) as well any activity
that might be shown by tracepoints if enabled when in this state
(trace-cmd start -e xfs:*; cat /sys/kernel/debug/tracing/trace_pipe)?

Brian

> David
>
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