Re: Re [9fans] union directories

Re: Re [9fans] union directories

[paurea]

>forsyth@caldo.demon.co.uk said:
>>bind -ac foo bar shoud give
>>*bar
>>foo
>>This is what I would expect intuitively. Of course you can always do ...

>i don't understand how this could be considered the `intuitive' interpret>ation.

The directory which is before for the lookup gets the creation. I
feel that is more consistent. If it is before, it is before for
everything...
					Saludos,
							Gorka

Re: Re [9fans] union directories

[rob pike]

	The directory which is before for the lookup gets the creation. I
	feel that is more consistent. If it is before, it is before for
	everything...

Russ is right; you can get this by mounting everything -c.

The canonical example that led us to the design we implemented
is /bin, which typically contains first a set of public unwritable
directories and second a set of personal writable ones.

-rob

Re: Re [9fans] union directories

[paurea]

[-- Attachment #1: Type: text/plain, Size: 207 bytes --]

Not really.  You can always do: (I am writing what I think it should
do, not what it actual behaviour..)

bind -ac foo bar
*bar
foo

bind -b foo bar
foo
*bar

						Saludos,
								Gorka




[-- Attachment #2: Type: message/rfc822, Size: 1957 bytes --]

From: "Russ Cox" <rsc@plan9.bell-labs.com>
To: 9fans@cse.psu.edu
Subject: Re: Re [9fans] union directories
Date: Thu, 22 Mar 2001 10:36:28 -0500
Message-ID: <20010322153635.40740199EE@mail.cse.psu.edu>

  The directory which is before for the lookup gets the creation. I
  feel that is more consistent. If it is before, it is before for
  everything...

If you want that, you can do that: use -c with all your
binds and the create will go to the top directory.

There are legitimate cases in which you want creates
to go to the bottom directory, though; your scheme
would disallow that.

Russ

Re: Re [9fans] union directories

[Russ Cox]

  The directory which is before for the lookup gets the creation. I
  feel that is more consistent. If it is before, it is before for
  everything...

If you want that, you can do that: use -c with all your
binds and the create will go to the top directory.

There are legitimate cases in which you want creates
to go to the bottom directory, though; your scheme
would disallow that.

Russ

Re: Re [9fans] union directories

[forsyth]

>>bind -ac foo bar shoud give
>>*bar
>>foo
>>This is what I would expect intuitively. Of course you can always do ...

i don't understand how this could be considered the `intuitive' interpretation.

Re [9fans] union directories

[Gorka Guardiola Muzquiz]

I don't think I have explained myself clearly, so I will try to do it again,
borrowing Russ's notation:
bind -bc foo bar should give:
*foo
bar
bind -ac foo bar shoud give
*bar
foo
This is what I would expect intuitively. Of course you can always do
bind -b foo bar 
to set the bar from the previous example to:
foo
*bar
foo
which is actually equivalent to:
foo
*bar
                        Saludos,
                                Gorka

Re [9fans] union directories

[Gorka Guardiola Muzquiz]

Russ> Actually that's the way it's supposed to work.
The manual says "creation goes to the first element of the union that 
permits creation". Doesn't that means that it should jump over non_writeble?
Even taking that in account, I can't see the logic behind this behaviour.
Lookup should win whenever creation wins. That would be symmetrical and
clean. with bind -ac n1 n2, bind -bc n1 n2, bind -ac n2 n1, bind -bc n2 n1
you would cover all the logical possibilities, and you save doing
something else, like running two commands or adding an extra flag for the 
rest of the cases where lookup!=creation. I can see the logic behind making
creation more or less independant from lookup, but the implementation for
is rather weird...
			Saludos,
				Gorka