Re: [PATCH 2/2] Enable v4 mounts when either "nfsvers=4" or "vers=4" option are set (vers-02)

[Steve Dickson <SteveD@redhat.com>]

On 08/25/2009 04:37 PM, Chuck Lever wrote:
>>>> Also note there is no '-o ' flag to umount so 'umount -t nfs -o v4' is
>>>> not valid... but 'umount -t nfs' is and works on both nfs4 and nfs
>>>> file systems.
>>>
>>> Sorry I wasn't clear.  I meant that umount.nfs should be able to read a
>>> line in /etc/mtab that has "nfs" and "v4" and do the right thing... then
>>> you wouldn't have to change the fs_type in /etc/mtab at all.
>> Ok.. I gotta you now... and I did take a few minutes to look into what
>> something like this would take... I quickly came to the realization
>> that adding all complexity to make a system file, that nobody see or
>> care about, more aesthetic really not worth it and not necessary,
>> IMHO....
> 
> It's more of a maintainability issue.  Make umount.nfs behave the same
> way for v2, v3, and v4, instead of doing one thing for v2/v3 and another
> for v4.
Then why even have a mount.nfs4 command? Lets simple get ride of that 
command all together and ignore the fact nfs and nfs4 are to separate 
filesystems? Personally I think this would be wrong... 

It was deemed, rightly so, that nfs4 would be a separate file system.
So there there will be things that will have to be done to maintain
both of them... All this patch set does is create a shorthand way of 
mounting an nfs4 file system... nothing more and nothing less... 
   
> 
>> Point being,  umount is so simple when it comes to umounting a nfs4 file
>> system... It basically does nothing! Which is a beautiful thing! So to
>> added
>> all the code (on both the mount and umount side) to translate
>> '-t nfs -o v4' into nfs4 (which  would have to happen since
>> del_mtab() takes a fs type) is just not worth it... Especially when
>> the other option is adding no code to the umount side...
> 
> I doubt it would be a lot of complexity, actually.  We already have
> parser calls in umount.nfs to handle v2/v3 version/transport
> negotiation, so I don't think it would be much of a stretch at all to
> look for "v4" before deciding whether to do a v2/v3 umount or a v4 umount.

Let's make a deal! ;-) If a bug report is opened about the exact user-given command 
arguments to the mount command are not portrayed correctly in /etc/mtab, 
I will fix that bug and then buy you dinner! :-) 

steved.