Odd NIS map failure with mount point creation time in the future?

Odd NIS map failure with mount point creation time in the future?

[James Pearson]

I using CentOS 5 on a large number of boxes with a NIS indirect 
automount map.

I've been using the following syntax in /etc/auto.master:

/mntpoint    yp:custom.map

And this has worked fine for ages

Recently, I wanted to provide some custom local overrides to mount 
points in the NIS map, so I've changed /etc/auto.master to be:

/mntpoint    custom.map

and created a file called /etc/custom.map which contains something like:

host1    host:/disk1
+custom.map

i.e. include the NIS map after any local mount point settings

On most machines, this works fine - but on a number of machines, after a 
reboot, the mounts from the NIS map fail to mount - although the other 
mounts from /etc/custom.map mount fine.

One thing I noticed in common on all the machines with this problem is 
that datestamp on the automount mount point (/mntpoint) was in the 
future - by an hour or two. I guess the hardware clock is an hour or two 
ahead of the real time.

ntp runs on all these boxes - but starts after autofs - however if I 
change ntp to startup before autofs, then autofs works fine after a 
reboot ...

Any idea why autofs fails to read entries from the included NIS map when 
the creation date of the map mount point is in the future? - but works 
fine when the same NIS map is referenced directly from /etc/auto.master?

James Pearson

Re: Odd NIS map failure with mount point creation time in the future?

[Ian Kent]

On Fri, 2011-06-17 at 15:12 +0100, James Pearson wrote:
> I using CentOS 5 on a large number of boxes with a NIS indirect 
> automount map.
> 
> I've been using the following syntax in /etc/auto.master:
> 
> /mntpoint    yp:custom.map
> 
> And this has worked fine for ages
> 
> Recently, I wanted to provide some custom local overrides to mount 
> points in the NIS map, so I've changed /etc/auto.master to be:
> 
> /mntpoint    custom.map
> 
> and created a file called /etc/custom.map which contains something like:
> 
> host1    host:/disk1
> +custom.map
> 
> i.e. include the NIS map after any local mount point settings
> 
> On most machines, this works fine - but on a number of machines, after a 
> reboot, the mounts from the NIS map fail to mount - although the other 
> mounts from /etc/custom.map mount fine.
> 
> One thing I noticed in common on all the machines with this problem is 
> that datestamp on the automount mount point (/mntpoint) was in the 
> future - by an hour or two. I guess the hardware clock is an hour or two 
> ahead of the real time.
> 
> ntp runs on all these boxes - but starts after autofs - however if I 
> change ntp to startup before autofs, then autofs works fine after a 
> reboot ...
> 
> Any idea why autofs fails to read entries from the included NIS map when 
> the creation date of the map mount point is in the future? - but works 
> fine when the same NIS map is referenced directly from /etc/auto.master?

Don't know about the timestamp but there were some included map fixes in
RHEL-5.7, at least one was a fix for a regression.

Versions?

> 
> James Pearson
> 
> _______________________________________________
> autofs mailing list
> autofs@linux.kernel.org
> http://linux.kernel.org/mailman/listinfo/autofs

Re: Odd NIS map failure with mount point creation time in the future?

[James Pearson]

Ian Kent wrote:
>>
>>Any idea why autofs fails to read entries from the included NIS map when 
>>the creation date of the map mount point is in the future? - but works 
>>fine when the same NIS map is referenced directly from /etc/auto.master?
> 
> 
> Don't know about the timestamp but there were some included map fixes in
> RHEL-5.7, at least one was a fix for a regression.
> 
> Versions?

Sorry, I should have said - this is CentOS 5.5 with autofs 
5.0.1-0.rc2.143.el5_5.6 - and I've also tried it with 
5.0.1-0.rc2.143.el5_6.2 - with the same result.

It is easy to reproduce - with an included NIS map - if I do:

/etc/init.d/autofs stop; date -s "1 minute"; /etc/init.d/autofs start; 
date -s "-1 minute"

This creates the automount mount point 1 minute into the future.

Then if I try to access a server defined in the NIS map, the mount fails.

However, if I wait a minute (i.e until the system clock passes the date 
stamp of the mount point), the automount of file systems in the NIS map 
works fine.

Is it possible to get a copy of the autofs RPM for RHEL-5.7 to test?

Thanks

James Pearson

Re: Odd NIS map failure with mount point creation time in the future?

[Ian Kent]

On Sat, 2011-06-18 at 21:08 +0100, James Pearson wrote:
> James Pearson wrote:
> > 
> > Sorry, I should have said - this is CentOS 5.5 with autofs 
> > 5.0.1-0.rc2.143.el5_5.6 - and I've also tried it with 
> > 5.0.1-0.rc2.143.el5_6.2 - with the same result.
> > 
> > It is easy to reproduce - with an included NIS map - if I do:
> > 
> > /etc/init.d/autofs stop; date -s "1 minute"; /etc/init.d/autofs start; 
> > date -s "-1 minute"
> > 
> > This creates the automount mount point 1 minute into the future.
> > 
> > Then if I try to access a server defined in the NIS map, the mount fails.
> > 
> > However, if I wait a minute (i.e until the system clock passes the date 
> > stamp of the mount point), the automount of file systems in the NIS map 
> > works fine.
> > 
> > Is it possible to get a copy of the autofs RPM for RHEL-5.7 to test?
> 
> I had a look at the RHEL5 5.0.1-0.rc2.143.el5_6.2 source - and the 
> following patch appears to 'fix' my problem - it's a bit of a hack - as 
> in the included NIS map case, it just resets the age of the map to 
> 'now', if it is in the future.
> 
> James Pearson
> 
> plain text document attachment (autofs-5.0.1-future.patch)
> --- ./daemon/lookup.c.mpc	2011-06-18 20:04:51.076507000 +0100
> +++ ./daemon/lookup.c	2011-06-18 20:52:18.436154033 +0100
> @@ -848,6 +848,12 @@ int lookup_nss_mount(struct autofs_point
>  	struct map_source *map;
>  	enum nsswitch_status status;
>  	int result = 0;
> +	time_t now = time(NULL);
> +
> +	if (entry->age > now) {
> +		debug(ap->logopt, "map %s age in the future - changing it to now", entry->path);
> +		entry->age = now;
> +	}
>  
>  	/*
>  	 * For each map source (ie. each entry for the mount

That sounds a bit like bug
https://bugzilla.redhat.com/show_bug.cgi?id=632471

It was fixed in development revision 152, which I happen to have on
people.redhat.com. You could give that a try.

http://people.redhat.com/~ikent/autofs-5.0.1-0.rc2.152.el5/

Keep in mind that there were a few other fixes that went into the final
release version so your mileage may vary.

Ian

Re: Odd NIS map failure with mount point creation time in the future?

[James Pearson]

Ian Kent wrote:
> 
> That sounds a bit like bug
> https://bugzilla.redhat.com/show_bug.cgi?id=632471

I don't have permission to view that bug ...

> It was fixed in development revision 152, which I happen to have on
> people.redhat.com. You could give that a try.
> 
> http://people.redhat.com/~ikent/autofs-5.0.1-0.rc2.152.el5/

Unfortunately, this version doesn't help ...

Thanks

James Pearson

Re: Odd NIS map failure with mount point creation time in the future?

[Ian Kent]

On Mon, 2011-06-20 at 11:45 +0100, James Pearson wrote:
> Ian Kent wrote:
> > 
> > That sounds a bit like bug
> > https://bugzilla.redhat.com/show_bug.cgi?id=632471
> 
> I don't have permission to view that bug ...
> 
> > It was fixed in development revision 152, which I happen to have on
> > people.redhat.com. You could give that a try.
> > 
> > http://people.redhat.com/~ikent/autofs-5.0.1-0.rc2.152.el5/
> 
> Unfortunately, this version doesn't help ...

OK, I'll try and reproduce it.

> 
> Thanks
> 
> James Pearson