Re: lots of unneeded filesystem modules?

[Stephen Powell <zlinuxman@wowway.com>]

On Sun, 4 Apr 2010 16:13:22 -0400 (EDT), Eric Cooper wrote:
> 
> I've noticed that after booting, my kernel has loaded almost every
> possible filesystem module (minix, qnx4, hfsplus, ...), even though I
> don't need anything but ext3 to boot.  Right now I'm going to
> blacklist all the others, but it would be nice to know why it's
> happening.
> 
> I do have a USB-attached printer with an empty card reader that shows
> up as a non-existent SCSI disk -- perhaps something is attempting to
> auto mount that?  If so, any suggestions on how to disable that
> behavior?
> 
> Please CC me on any responses since I'm not subscribed. Thanks.

Blacklisting modules only prevents the hotplug system (i.e. udev)
from loading them.  They can still be loaded manually by the modprobe
command or automatically by the kernel.  You really need to figure
out *what* is causing them to be loaded.

The following information which I extracted from the man page for
"mount" may be of interest:

   If  no  -t  option  is  given, or if the auto type is specified,
   mount will try to guess the desired type.  Mount uses the  blkid
   or  volume_id  library for guessing the filesystem type; if that
   does not turn up anything that looks familiar, mount will try to
   read  the  file  /etc/filesystems,  or,  if that does not exist,
   /proc/filesystems.  All of the  filesystem  types  listed  there
   will  be tried, except for those that are labeled "nodev" (e.g.,
   devpts, proc and nfs).  If /etc/filesystems ends in a line  with
   a single * only, mount will read /proc/filesystems afterwards.

   The auto type may be useful for user-mounted floppies.  Creating
   a file /etc/filesystems can be useful to change the probe  order
   (e.g.,  to  try vfat before msdos or ext3 before ext2) or if you
   use a kernel module autoloader.  Warning:  the  probing  uses  a
   heuristic  (the presence of appropriate `magic'), and could rec-
   ognize the wrong filesystem  type,  possibly  with  catastrophic
   consequences.  If  your  data  is  valuable,  don't ask mount to
   guess.

-- 
  .''`.     Stephen Powell    <zlinuxman@wowway.com>
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