Re: Analyzed/Solved: Booting 2.6.30-rc2-git7 very slow

[Al Viro <viro@ZenIV.linux.org.uk>]

On Wed, Apr 29, 2009 at 04:18:45PM +0200, Mike Galbraith wrote:
> > /etc/fstab, perhaps?  That definitely looks like two mount(2) had to
> > have been done to cause that...
> 
> Yeah, but how does one go about doing that?
> 
> Using mount -f, I can convince mount to succeed, but I still have only
> one entry in /proc/mounts, despite what my mount binary imagines.

Huh?
       -f     Causes  everything to be done except for the actual system call;
              if it's not obvious, this ``fakes'' mounting  the  file  system.
              This  option is useful in conjunction with the -v flag to deter-
              mine what the mount command is trying to do. It can also be used
              to add entries for devices that were mounted earlier with the -n

What are you talking about?

The interesting part is why mount(2) doesn't fail with -EBUSY on that
overmounting.  Is there anything else mounted on /sys?  That, or any
interesting patches applied to the tree (fs/sysfs/mount.c, fs/namespace.c)