Subject: Re: Improving the Unix API
To: der Mouse <mouse@Rodents.Montreal.QC.CA>
From: Alexander Viro <>
List: tech-kern
Date: 06/27/1999 13:50:02

On Sun, 27 Jun 1999, der Mouse wrote:

> > Another problem was the ability to change the mount status of a partition
> > from read-write to read-only or to unmounted,
> See NetBSD (and presumably other BSD) "mount -o update,rdonly" and/or
> "umount -f".  (Last I tried, the latter didn't work as it should, but
> that's a matter of fixing bugs rather than introducing new features.)

mount -o remount,ro on Linux. What was the problem? Indeed you can't do it
if you have files opened for write there (or pending removal of files
from unlinks), but that limitation is reasonable, IMHO.

> > As for the opening with no permissions - well, it would make *big*
> > sense if we could narrow down the API and move chown(), chmod(), etc.
> > into libc leaving f-variants in the kernel.
> I really don't like that.  The reasons why are (1) this means you have
> to have an fd free to do them; (2) it triples the number of user/kernel
> crossings involved.

The former is not too terrible, but the latter... Yup.

> > Extreme variant might include {set,get}sockopt extended to files and
> > doing both *stat and *ch{mod,own,flags} via that.
> If done, I think the name should be changed.  They are ?etSOCKopt,
> after all.  I'm not fond of this, though; it amounts to returning to
> using ioctl() for the tasks - albeit with a slightly different name.

The *only* way to make it reasonable would be to have a hierarchical
namespace for the options. Otherwise you are just getting the ioctl()
mess, and that's the last thing I'ld like to see.

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