devlabel: added multipath support

devlabel: added multipath support

[Gary_Lerhaupt]

Devlabel 0.35.21 includes support for multipath devices.

Previously, if attempting to add a symlink to a device which was part of a
multipath set, devlabel would not allow this because multiple devices
returned the same UUID. Now, this can be avoided by adding symlinks with the
--multipath option.

This will instruct devlabel to create multiple symlinks named
YourSymlinkName_multipath# each pointing to a different path that is part of
the multipath set. These symlinks can then be used in /etc/raidtab to create
a working multipath device which will not succumb to any device renaming
problems.

Hence, if /dev/sdd1 and /dev/sde1 were multiple paths to the same device,
they can now be referenced as /dev/foo_multipath0 and /dev/foo_multipath1 so
even if they became /dev/sdb1 and /dev/sdc1 internally, your multipath
device would still get created properly from /etc/raidtab since you used the
symlink names and not the actual device names.

tarball: http://www.lerhaupt.com/devlabel/devlabel-0.35.21.tar.gz
changeblog: http://www.lerhaupt.com/foo/archives/000063.html

---
Devlabel now handles the following device renaming related events:
* An unchanging symlink name which will always get you to the right location

* A method for identifying partitions which have no filesystem on them (eg.
swap) which would not otherwise be mountable by a filesystem label 
* If using raw devices, a consistently named file node to point to your data

* An engine for cluster deployment in shared storage environments 
* An automounter for hotpluggable storage devices which will mount a storage
device's associated symlink when its plugged in 
* A set of consistently named symlinks to be used for a multipath device in
/etc/raidtab 
* A method to ensure correct device ownership and permissions when device
renaming events occur  

Gary Lerhaupt
Linux Development
Dell Computer Corporation