Re: Reshape stalls and fails when SELinux is enabled

[NeilBrown <nfbrown@novell.com>]

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On Fri, Dec 11 2015, Edward Kuns wrote:

> I ran into this as well.  I unwisely worked around it by placing the
> backup file on /tmp.  I don't recommend that choice!  I didn't see
> your AVC on your EMail, but I recommend you reach out to the SELinux
> folks for labeling help.  I've reach out to them in the past and have
> found them very helpful (as are the folks here).  Getting the labeling
> corrected will not only help you but everyone else in the long term.
>
> I agree that it would be good for mdadm to handle this kind of failure
> in a more productive fashion as well.  But I'm only a lurker here.  I
> don't have enough knowledge to suggest what would be better.  One
> thing that really helped me debug this was commenting out the lines
>
> #StandardOutput=null
> #StandardError=null
>
> in the systemd file /lib/systemd/system/mdadm-grow-continue@.service
> -- note you have to run systemctl daemon-reload after changing the
> file for the change to be noticed.
>
> Once I did that, the system logs had much more useful information.
> I'm not sure where that file is sourced, whether it's from the
> linux-raid people or from the distributions or somewhere in between.
> Does anyone here know if there's a reason why standard out and
> standard error are sent to /dev/null for this service?

That mdadm-grow-continue@.service file is part of mdadm (in the systemd
directory).
As for why stdout/err is set to 'null', you could try finding out who
did that and ask them ....

http://git.neil.brown.name/?p=mdadm.git;a=commitdiff;h=5e76dce1acd906e8fc8af04973c3a129cdc77fd6

but I'm pretty sure that he has no idea.

You could try sending me a patch which changes those lines and gives some
sort of explanation why it is a good change to make.
There is a very good chance that I would apply that patch.

Thanks,
NeilBrown

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