zfs_mount_at() mounts a dataset at an arbitrary mountpoint rather than
at the configured mountpoint. This may be used by consumers that wish to
temporarily expose a dataset at another mountpoint without altering
dataset/pool properties.
This will be used by FreeBSD's libbe be_mount(), which mounts a boot
environment at an arbitrary mountpoint.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Kyle Evans <kevans@FreeBSD.org>
Closes#9833
68a192e4b7