zfs hold and release

[hhhappe]

I was searching for the use of zfs hold and release and couldn't find it.

The use case is to allow the source to manage snapshot creation and deletion, while not deleting snapshots until the destination has a copy. The destination does not need to be allowed to delete snapshots, only to "zfs release" a hold tag on a snapshot.

[whoschek]

There's no explicit support for holds in bzfs as I believe the bookmark feature makes holds (and their associated complexity issues) mostly unnecessary. Give it a shot.