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Date: Fri, 15 Sep 2017 13:30:37 +0300
From: Konstantin Belousov <kostikbel@gmail.com>
To: Edward Napierala <trasz@freebsd.org>
Cc: Kirk McKusick <mckusick@mckusick.com>, freebsd-fs <freebsd-fs@freebsd.org>,
 Andriy Gapon <avg@freebsd.org>,
 "freebsd-arch@freebsd.org" <freebsd-arch@freebsd.org>
Subject: Re: mount / unmount and mountcheckdirs()
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On Fri, Sep 15, 2017 at 11:08:31AM +0100, Edward Napierala wrote:
> 2017-09-15 10:20 GMT+01:00 Konstantin Belousov <kostikbel@gmail.com>:
> > I believe that the current autofs does not allow a process to get into
> > this situation at all.
> >
> 
> It does.  For example:
> 
> [trasz@v2:~]% cd /media/md0
> [trasz@v2:/media/md0]% mount
> /dev/ada0s1a on / (ufs, local, noatime, journaled soft-updates)
> devfs on /dev (devfs, local, multilabel)
> map -hosts on /net (autofs)
> map -media on /media (autofs)
> [trasz@v2:/media/md0]% ls
> [trasz@v2:/media/md0]% mount
> /dev/ada0s1a on / (ufs, local, noatime, journaled soft-updates)
> devfs on /dev (devfs, local, multilabel)
> map -hosts on /net (autofs)
> map -media on /media (autofs)
> /dev/md0 on /media/md0 (ufs, local, noatime, nosuid, automounted)
> 
> Getting rid of mountcheckdirs() in the unmount path should be fine, I think.
How the example proves that mountcheckdirs() can be removed ?  How can
we see which directory content was printed by ls, the covered or mounted ?