Re: mount_union info (was mount_overlay info)

["David Dudley" <DavidDu%cctexas.com@localhost>]

Should have read the manual better.

Problem I have, is that with things setup that way, I can't write into 
directories that are in the read-only area.

The program I run moves down into directories in the read-only tree, and then 
trys to create files in that area.

>From the manual:
—-----------------------
    Requests to create or modify objects in uniondir are passed to the upper
     layer with the exception of a few special cases.  An attempt to open for
     writing a file which exists in the lower layer causes a copy of the
     entire file to be made to the upper layer, and then for the upper layer
     copy to be opened.  Similarly, an attempt to truncate a lower layer file
     to zero length causes an empty file to be created in the upper layer.
     Any other operation which would ultimately require modification to the
     lower layer fails with EROFS.
—------------------------

Doesn't seem to do that.

David


>>> Jukka Salmi <j+nbsd%2008.salmi.ch@localhost> 11/13/2008 1:05 PM >>>
David Dudley --> current-users (2008-11-13 12:15:35 -0600):
> Well, this gets me really close to what I actually want to do   ;-)
> 
> What I'm actually attempting to do is the reverse of what _union does. 
> I want to mount a directory <under> another.
> 
> In other words, I want to have a directory tree where files come from
> another directory if they are not found in the directory I'm in (not
> sure I explained that correctly, but playing with the command seems to
> allow what I'm looking for, just in the wrong order).

Quoting mount_union(8):

-b      Invert the default position, so that directory becomes the lower
        layer and uniondir becomes the upper layer.  However, uniondir
        remains the mount point.

If that's not what you want I don't understand your question... ;-)


Regards, Jukka

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