zfs discuss - Jul 2006 - zfs filesystem/path names args with leading /

What danger is there in stripping off the leading / from zfs
command args and using what is left as a filesystem name?

Quite often I do a quick copy-paste to get from df output
to the zfs command line and every time I need to re-edit
the command line because the copy-paste takes the leading
/ with it.

Darren

On Mon, 2006-07-03 at 18:02 +0800, Darren Reed wrote:
> What danger is there in stripping off the leading / from zfs
> command args and using what is left as a filesystem name?
If I''m understanding you correctly, then you can''t do that, as
the
mountpoint isn''t always the same as the name of the filesystem.

For example:

timf at haiiro[513] df | grep local
/usr/local         (space/usrlocal    ):17092419 blocks 17092419 files
/usr/local/foo     (space/usrlocal/foo):17092419 blocks 17092419 files


Of course, there''s nothing stopping you taking the middle field
(enclosed in parenthesis) from df instead.

	does this help ?

	cheers,
			tim


-- 
Tim Foster, Sun Microsystems Inc, Operating Platforms Group
Engineering Operations            http://blogs.sun.com/timf

Tim Foster wrote:
>On Mon, 2006-07-03 at 18:02 +0800, Darren Reed wrote:
>  
>
>>What danger is there in stripping off the leading / from zfs
>>command args and using what is left as a filesystem name?
>>    
>>
>
>If I''m understanding you correctly, then you can''t do
that, as the
>mountpoint isn''t always the same as the name of the filesystem.
>
>For example:
>
>timf at haiiro[513] df | grep local
>/usr/local         (space/usrlocal    ):17092419 blocks 17092419 files
>/usr/local/foo     (space/usrlocal/foo):17092419 blocks 17092419 files
>
>
>Of course, there''s nothing stopping you taking the middle field
>(enclosed in parenthesis) from df instead.
>  
>
Well, I use "df -kl", but commands such as "df" will work
just
the same if I use "." or "/" or
"/dev/dsk/c0t3d0s0" (and all three
are the same.)

Yes, arguably I am cut-past''ing the wrong part of the output..

I suppose what I''m questioning is, whether or not there is any
real danger in zfs converting /usr/local to usr/local and then
trying to do a delete of the filesystem usr/local.  I suppose this
could mounted in /opt/local and be not what I wanted...

But in the case where the ZFS mountpoint is the ZFS filesystem
name (plus a leading /), why not allow both names to mean the same?

Darren

On Mon, Jul 03, 2006 at 06:43:59PM +0800, Darren Reed
wrote:
> 
> Well, I use "df -kl", but commands such as "df" will
work just
> the same if I use "." or "/" or
"/dev/dsk/c0t3d0s0" (and all three
> are the same.)
> 
> Yes, arguably I am cut-past''ing the wrong part of the output..
> 
> I suppose what I''m questioning is, whether or not there is any
> real danger in zfs converting /usr/local to usr/local and then
> trying to do a delete of the filesystem usr/local.  I suppose this
> could mounted in /opt/local and be not what I wanted...
> 
> But in the case where the ZFS mountpoint is the ZFS filesystem
> name (plus a leading /), why not allow both names to mean the same?
A better solution would be fixing this RFE:

6260523 want ''zfs list <path>''

Which could also be expanded to other zfs(1M) commands.  This would do
the statvfs()/getmntany() to find the associated zfs dataset, regardless
of whether it matches the mountpoint or not.

- Eric

--
Eric Schrock, Solaris Kernel Development       http://blogs.sun.com/eschrock