could a new option please be added to dump that allows the explicit setting of the filesystem name (much like -D does for restore)?
reasoning is as follows:
with the possibility of taking snapshots of a file system (well, of the underlying block device with lvm, but that doesn't change the point) it became possible dumping the snapshot blockdev instead of the live one, which helps a lot with having consistent backups. now, if such a snapshot not mounted when dumped, the filesystem will get set to "an unlisted filesystem", which just loses a very important piece of metadata. granted one can mount the snapshot to a temporary location and dump that, but then the temporary location's mount point will get recorded, which is also a loss of that important piece of metadata, unless one goes into hoops of creating a mount point that somehow sensibly represents the original mount point, and then there may still be fallouts.
instead of all this dance an option to set the filesystem explicitly would reduce the above imaginary scenario to the following (assuming /dev/vg0/dump-snap is the snapshot lv and a snapshot of the the root filesystem is being dumped):
dump -x / /dev/vg0/dump-snap
(or any other convenient switch instead of -x).
this would also help dumpdates to better reflect what and when has really been dumped