Re: [PATCH] lazy umount (1/4)

[Linus Torvalds]

On Fri, 14 Sep 2001, Alexander Viro wrote:
>
> There are only two things to take care of -
> 	a) if we detach a parent we should do it for all children
> 	b) we should not mount anything on "floating" vfsmounts.
> Both are obviously staisfied for current code (presence of children
> means that vfsmount is busy and we can't mount on something that
> doesn't exist).

I disagree about the "we can't mount on something that doesn't exist"
part.

If the detached mount is busy, it might be busy exactly because somebody
has his working directory in it. Which means that

	mount /dev/hda ./xxxx

by such a process could cause a mount within the "nonexisting" mount.

		Linus