Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2014-11-28 10:50, Gilles Chanteperdrix wrote:
> On Fri, Nov 28, 2014 at 10:40:27AM +0100, Jan Kiszka wrote:
>> On 2014-11-28 00:15, Gilles Chanteperdrix wrote:
>>> On Thu, Nov 27, 2014 at 09:43:34PM +0100, Jan Kiszka wrote:
>>>> On 2014-11-27 21:34, Gilles Chanteperdrix wrote:
>>>>> On Thu, Nov 27, 2014 at 02:14:38PM -0500, Lennart Sorensen wrote:
>>>>>> On Thu, Nov 27, 2014 at 07:51:27PM +0100, Jan Kiszka wrote:
>>>>>>> On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
>>>>>>>> According to the filesystem hierarchy standard, /mnt is the standard
>>>>>>>> place for "temporarily mounted filesystems".
>>>>>>>>
>>>>>>>> http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
>>>>>>>
>>>>>>> Right, another reason to NOT mess around with it: if something was
>>>>>>> temporarily mounted there, we will create the mountpoint inside that
>>>>>>> filesystem with unforeseeable side effects.
>>>>>>
>>>>>> I always read that as "temporarily mounted there by the admin or some
>>>>>> other human".  Certainly not automatic mounts by software.  There is a
>>>>>> reason /media and such exists on many distributins.
>>>>>
>>>>> I would not venture an "always", autofs for instance, used to mount
>>>>> things under /mnt. and /media has not always existed either, we used
>>>>> /mnt/cdrom.
>>>>
>>>> FHS on /mnt purpose:
>>>>
>>>> "This directory is provided so that the system administrator may
>>>> temporarily mount a filesystem as needed. The content of this directory
>>>> is a local issue and should not affect the manner in which any program
>>>> is run."
>>>>
>>>> I think this makes it crystal clear that Xenomai is not supposed to
>>>> touch it.
>>>
>>> Just to add another argument. I just asked a friend who is a
>>> professional sysadmin. He creates directory under /mnt and mount
>>> things under these directories. So, I am not sure the standard is
>>> even applied by the people who should use it.
>>>
>>> If you read on the last site I sent, under the /media article: 
>>>
>>> Amid much controversy and consternation on the part of system and
>>> network administrators a directory containing mount points for
>>> removable media has now been created. Funnily enough, it has been
>>> named /media.
>>>
>>> Are you sure, 100% sure, that every Xenomai user expects to be able
>>> to use /mnt as a mount point? Or that they will create directories
>>> under /mnt like everybody has been doing since Linux exists?
>>
>> I'm both absolutely sure that a) has to be left alone by Xenomai because
>> of requirements of the FHS and the way /mnt is used and b) we should try
>> hard to avoid creating temporary dirs in persistent filesystems.
> 
> This is ridiculous. Because the standard changed, and one
> distribution, Debian, decided to follow the new standard, which
> seems to be not widely accepted, and even controversial, you want to
> impose what Debian does to everybody. The distribution I use has
> mount points under /mnt. So, why following Debian and not the
> distribution I use, and what sysadmin have been doing for ages?
> 
> You want the mount point to be somewhere else? Fine, put a symbolic
> link.
> 
> mkdir /run/xenomai
> ln -s /run/xenomai /mnt/xenomai

Again, this is not acceptible as /mnt changes all the time and exposes
various remote filesystems which will hide that link. /mnt is locally
owned, not by the system to which Xenomai belongs, please accept this.
You can still define your personal setup differently if the path is not
easily fixable there.

Jan

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