Re: [mdadm PATCH 5/9] mdmon: mdmon_pid should return pid from either dir

[Neil Brown <neilb@suse.de>]

On Wed, 3 Mar 2010 07:44:03 +0100
Luca Berra <bluca@comedia.it> wrote:

> On Wed, Mar 03, 2010 at 12:50:31PM +1100, Neil Brown wrote:
> >On Sun, 28 Feb 2010 15:43:40 +0100
> >Luca Berra <bluca@comedia.it> wrote:
> >
> >> mdmon_pid is called by mdmon_running to check if mdmon is running, so
> >> the pid file should be checked in either VAR_RUN or ALT_RUN
> >
> >I don't agree with this.
> >
> >The only time that any code should care about ALT_RUN is when mdmon is
> >starting.  It chooses VAR_RUN or ALT_RUN to use, and possibly looks for an
> >old instance to kill.
> >
> >When starting mdmon without "--takeover", if it decided to use VAR_RUN, it
> >would not check ALT_RUN to see if an old mdmon was running.  So I have
> >replaced you patch with a patch to include that extra check when starting
> >mdmon without --takeover.
> >Maybe that is the case you intended to address??
> 
> No,
> the problem i try to address is in mdadm, not mdmon
> When mdadm needs to manage arrays with external metadata it will look
> for mdmon using mdmon_running(). If mdmon is running but did not yet
> take over mdadm will refuse to operate stating that mdmon is not
> running.
> 
> I had to mount --bind ALT_RUN VAR_RUN in order to repair my imsm on
> sunday morning.

Ahhh..
I would rather you did
  mdmon --takeover --all

which would effectively move the key fines from ALT_RUN to VAR_RUN.

Would that have worked in your case?

NeilBrown