(ext3 + (2.4.18 -> 2.6.11)) = WTF?

[aluminumsulfate at earthlink.net]

   From: "Michael ODonnell" <michael.odonnell at comcast.net>
   Reply-To: "GNHLUG" <gnhlug-discuss at mail.gnhlug.org>

<snip>

   The thing that's got me irked is that I can't mount
   either of those non-root ext3 filesystems; the mount
   command instead just complains about how either the device
   appears to already be mounted or else the mount point is
   busy, neither of which is true.  If I create a fresh mount
   point under /tmp I still cannot mount either of those ext3
   filesystems there (same complaint) while at the same time I
   can readily mount any other filesystem on the mount points
   in question, so they're apparently not really busy.

Well, I have a *few* guesses:

Theory A: Your distro auto-mounted these disks at some mystery
       mount point it hasn't told you about, causing mount to
       complain when you try to remount the disks.

Theory B: You're using an initrd and aren't unmounting the
       disks before mounting the "real" root filesystem.

Theory C: Your mtab is somehow messed up, either causing mount
       to get confused or bring about "Theory A", above.

Theory D: Some other program (losetup, fsck, etc.) has your
       devices open.

(This is, of course, assuming that this isn't a fresh install,
 but that you're just rebooting an existing installation with
 a new kernel. And that you're not using LVM or md....)

I'd look through /etc/{f,m}tab and /proc/mounts, comparing...
And use fuser to see who claims to have an open device.

Dave