[Devel] Re: Question for remount

[KAMEZAWA Hiroyuki]

On Mon, 23 Feb 2009 10:32:46 +0800
Li Zefan <lizf at cn.fujitsu.com> wrote:

> KAMEZAWA Hiroyuki wrote:
> > Paul Menage さんは書きました：
> >> On Fri, Feb 20, 2009 at 2:02 AM, KAMEZAWA Hiroyuki
> >> <kamezawa.hiroyu at jp.fujitsu.com> wrote:
> >>> 2. /proc/mounts information of release_agent should be updated....
> >>>   when it's overwritten directly.
> >> Yes, definitely. But shouldn't that happen already?
> >> cgroup_show_options() reports the current value of
> >> root->release_agent_path in /proc/mounts. Is it possible that mount is
> >> actually storing/retrieving this information in /etc/mtab, which
> >> doesn't get updated?
> >>
> > Ah, you're right. /proc/mounts is updated but /etc/mtab is not updated.
> > Hmm..from man mount(1), /etc/mtab is not synchronized with /proc/mounts.
> > Do we need to allow release_agent override at remount ?
> > 
> 
> Since we've allowed this behavior, I think we shouldn't disallow it to
> supprise users?
> 
In a bit different stroy, it already surprises a user (me).
for example)

#mount -t cgroup none /cgroups -ocpu,release_agent=hogehoge
#mount -oremount,cpuacct /cgroups,release_agent=xxxx
=> remount fails. because the option "release_agent" appears twice.

#mount -t cgroup none /cgroups -ocpu,release_agent=hogehoge
#mount -t cgroup none /cgroups -oremount,cpuacct /cgroups,release_agent=xxxx
=> remount success.

At least, updating documentation to notice this is necessary I think.


-Kame

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