Re: silent semantic changes with reiser4

Jamie Lokier
2004-08-26T19:53:37Z

Linus Torvalds wrote:
> > It is not the kernel which decides. The filesystem containing
> > /dev/hda/part1 opens "the directory branch".
>
> But that filesystem cannot know what the _other_ filesystem configurations
> are. And that's what you'd have to have to mount.

At which point, userspace comes in. Who knows what userspace chooses.

> > The obvious implementation has the userspace helper just mounting it,
> > end of story. If the mount command fails, it fails. Much like autofs.
>
> Yes, that would work, but it's of questionable use. If you want autofs,
> then just _use_ autofs.

I don't mean to imply it's useful behaviour: only that it seems to
happen by default if you don't do anything special to prevent it, if
you see what I mean.

It does seem useful to have _files_ mounted automagically (using
loopback devices): for example, cd into a .iso file and it would be
nice to see the contents. At this point, deciding on the preferred
-EBUSY or not behaviour becomes relevant, as does deciding whether the
.iso in this example is viewed using the kernel's isofs code, or using
a userspace helper in the same way as we'd use one to browse a .zip file.

-- Jamie