Q: (RFE?) How do you specify the 'no-canonicalize' option in fstab?

Q: (RFE?) How do you specify the 'no-canonicalize' option in fstab?

[Linda A. Walsh]

While it works interactively, that leaves out using it when most of the file
systems are loaded -- how can one specify -no-canonicalize in /etc/fstab?

Thx!
Linda

Re: Q: (RFE?) How do you specify the 'no-canonicalize' option in fstab?

[Karel Zak]

On Wed, Jul 23, 2014 at 09:32:55PM -0700, Linda A. Walsh wrote:
> While it works interactively, that leaves out using it when most of the file
> systems are loaded -- how can one specify -no-canonicalize in /etc/fstab?

 Why do you want something like this? 
 
 The option --no-canonicalize has very special purpose (e.g. when
 mount.<type> helper calls mount(8)).

    Karel


-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

Re: Q: (RFE?) How do you specify the 'no-canonicalize' option in fstab?

[Linda A. Walsh]

Karel Zak wrote:
> On Wed, Jul 23, 2014 at 09:32:55PM -0700, Linda A. Walsh wrote:
>   
>> While it works interactively, that leaves out using it when most of the file
>> systems are loaded -- how can one specify -no-canonicalize in /etc/fstab?
>>     
>
>  Why do you want something like this? 
>   
----
Why wouldn't I?


>  
>  The option --no-canonicalize has very special purpose (e.g. when
>  mount.<type> helper calls mount(8)).
>   
The default canonicalization has a very special purpose to the 
kernel/dm, but it
is not necessarily what a user wants to see when they type 'mount'.

Is there a reason NOT to give the option to user to display it as they wish,
or is there some reason to force the user into using the kernel/lvm internal
format?

Re: Q: (RFE?) How do you specify the 'no-canonicalize' option in fstab?

[Karel Zak]

On Thu, Jul 24, 2014 at 07:20:51PM -0700, Linda A. Walsh wrote:
> Karel Zak wrote:
> >On Wed, Jul 23, 2014 at 09:32:55PM -0700, Linda A. Walsh wrote:
> >>While it works interactively, that leaves out using it when most of the file
> >>systems are loaded -- how can one specify -no-canonicalize in /etc/fstab?
> >
> > Why do you want something like this?
> ----
> Why wouldn't I?

Well, I'm trying to help you, so it would be nice to have more
information about your use-case...

> > The option --no-canonicalize has very special purpose (e.g. when
> > mount.<type> helper calls mount(8)).
> The default canonicalization has a very special purpose to the kernel/dm,
> but it
> is not necessarily what a user wants to see when they type 'mount'.

Do you mean that you want to see kernel device names for DM when you
list all mountpoint by 'mount'?

> Is there a reason NOT to give the option to user to display it as they wish,
> or is there some reason to force the user into using the kernel/lvm internal
> format?

/dev/dm-0 is internal format that is unexpected for users, DM guys
don't want to see these names in the df, mount, .. outputs. 

Anyway, the goal is to keep device names and mounpoints paths for
mount(2) syscall in some well know (canonical) format, to make it fast
to search in mount tables, etc.

You can use "lsblk -o+KNAME" if you want to see the kernel device names. 

Maybe we can add KNAME also to findmnt(8) to make the name accessible from list
of the mounted filesystem, but don't expect any change in mount(8). It's bad 
idea to change the way how we use devices for mounting just for reason that 
you want to see something else in 'mount' output. It's better to improve 
things like findmnt(8).

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

Re: Q: (RFE?) How do you specify the 'no-canonicalize' option in fstab?

[Linda A. Walsh]

Karel Zak wrote:
> Do you mean that you want to see kernel device names for DM when you
> list all mountpoint by 'mount'?
---
That would be worse (I think).
> /dev/dm-0 is internal format that is unexpected for users, DM guys
----
    The time it takes for a computer to translate between formats is
negligible compared to the time it takes for users to find ways to work
around the name mangling.

    What I'd like seems completely straight forward.  Use the names the user
used in their /etc/fstab  or their mount line.  Don't convert it.  MS 
has been
doing this on Windows at least since Vista -- in regards to 'case' -- they
preserve the case the user uses, but ignore it for looking up file names.

    Here, if the user uses the suggested lvm names of /dev/VG/LV, then
I would want to see those names when I type "mount".


    Example from "bash" and path following in presence of symlinks.

If I am in /home/user and cd to "work", where "work" is a symlink pointing
to /Data/Work, if I type "cd .." in work, I want to be back in the directory
I started from not "/Data".  

Honoring user-symbolic names has become the "default" case, because it's 
user
friendly -- it's what users expect to see.  I hold that doing the same thing
in lvm volume names as in filesystem paths including symlinks, would be
consistency -- using the "user's input" to generate and follow state.

Forcing users into some arbitrary nomenclature which changes over the 
years as
new features are implemented, isn't especially user friendly.

So I want to be able to use "no-canonicalize" to KEEP the names I use -- the
*preferred* names, I am told, for the product (lvm).

Ask yourself this question, if you use bash, do you turn on physical
path resolution (set -P in your .bashrc?) (the default is to emulate a
symlinked-structure).  If you don't use -P there, why would you want to
force a physical name on your logical volumes?

Re: Q: (RFE?) How do you specify the 'no-canonicalize' option in fstab?

[Linda A. Walsh]

Karel Zak wrote:
>>>> no-canonicalize in /etc/fstab?
>>> Why do you want something like this?
> Well, I'm trying to help you, so it would be nice to have more
> information about your use-case...
---
    Was my description still unclear?  when I use a "symbolic link"
to a file or to a device, when I look at where I am, I want to
see what I typed in as part of the path.

If I'm in my home dir, I can cd into
bin/audio to work on scripts.  If I want to test with large
files, they are in /Audio, where the scripts dir is
under /Audio/scripts.

If I am making a short change and not testing, I usually
work by cd'ing into the local path ~/bin/audio -- I wouldn't
be real happy if it dumped me in /Audio/scripts each time, even
though that would be a canonical name.

Same with Devnames -- If I use the standard /dev/VG/LV in
constructing a name, being passed a mutated form forces an
automated script to go belly up -- looking for the VG after
/dev/, and looking for LV's under the VG.

So in my usecase, I'd like to mount the volumes using
/etc/fstab and still be able to use the no-canonicalize
option. 


??  Reasonable to be able to specify the switch
via fstab and provide consistency with the command
line option?