Re: [PATCH 2/2] mount: add --enable-libmount-mount

[Karel Zak <kzak@redhat.com>]

On Thu, Mar 03, 2011 at 02:53:06PM -0500, Steve Dickson wrote:
> > +	opts = retrieve_mount_options(mnt_context_get_fs(cxt));
> > +
> > +	if (!mnt_context_is_lazy(cxt)) {
> > +		if (opts) {
> > +			/* we have full FS description (e.g. from mtab or /proc) */
> > +			switch (is_vers4(cxt)) {
> > +			case 0:
> > +				/* We ignore the error from nfs_umount23.
> > +				 * If the actual umount succeeds (in del_mtab),
> > +				 * we don't want to signal an error, as that
> > +				 * could cause /sbin/mount to retry!
> > +				 */
> > +				nfs_umount23(mnt_context_get_source(cxt), opts);
> > +				break;
> > +			case 1:			/* unknown */
> > +				break;
> > +			default:		/* error */
> > +				goto err;
> > +			}
> > +		} else
> > +			/* strange, no entry in mtab or /proc not mounted */
> > +			nfs_umount23(spec, "tcp,v3");
> Question: since retrieve_mount_options() returns NULL why do you assume 
> the mount exists?

 because on systems with /etc/mtab is possible that the file is empty,
 so we have no clue about the mount point.
 
 This is normal umount(8) behavior, for root user it always tries to
 call umount(2) syscall. We should not assume that there is usable
 /proc or /etc/mtab. It's important be able to umount any device
 independently on /proc or /etc.

 See nfsumount.c, the current code uses the same logic.

> What's happing is I'm doing an umount.nfs on an 
> not existing mount point and the error is 
>     umount.nfs: remote share not in 'host:dir' format
> 
> Instead of
>     umount.nfs: /mnt/home: not mounted

 Good catch, this is bug. There is missing umount_error();

 I'll update the patch and add your change to mount_config_init() too.

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com