Mounting nested ZFS filesystems exported via NFS

I have a linux (ubuntu) server with a zfs pool containing nested fileystem. E.g.: zfs_pool/root_fs/fs1 zfs_pool/root_fs/fs2 zfs_pool/root_fs/fs3 I have enabled NFS sharing on the root filesystem (via zfs, not by editing /etc/exports). Nested filesystems inherit this property. NAME PROPERTY VALUE SOURCE zfs_pool/root_fs sharenfs rw=192.168.1.0/24,root_squash,async local NAME PROPERTY VALUE SOURCE zfs_pool/root_fs/fs1 sharenfs rw=192.168.1.0/24,root_squash,async inherited from zfs_pool/root_fs On the client machines (linux, mostly ubuntu), the only filesystem I explicitly mount is the root filesystem. mount -t nfs zfsserver:/zfs_pool/root_fs /root_fs_mountpoint Nested filesystems are mounted automatically when they are accessed. I didn't need to configure anything to make this work. This is great, but I'd like to know who is providing this feature. Is it ZFS? Is it NFS? Is it something else on the client side (something like autofs, which isn't even installed). I'd like to change the timeout after which nested filesystems are unmounted, but I don't even know which configuration to edit and which documentation to read.