FreeNAS Code

Clean up cornercase where a zvol, dataset, zpool in use when deleting a zvol would delete the zvol from the GUI/db, but wouldn't actually remove things from the backend in FreeBSD.

Introduce a few new notifier APIs to help ease this pain:

__get_mountpath - get the mountpath for a volume/dataset (name)
__rmdir_mountpoint - remove a mountpoint as a means to determine whether or not the

Split storage.models.Volumes.delete into two functions again to 'clean up' the database after storage.models.Volumes._delete has been run, in such a manner that the mountpoints aren't preemptively removed, even though some of the dataset / zvol objects might have been successfully removed, and instead are removed in the event that the directory, that previously was the mountpoint, is no longer present.

These APIs are coded relatively conservatively for now to avoid putting the user into situations where they need to do database surgery.. they can and should be cleaned up later to be more explicit and straightforward by tossing proper Exceptions up the stack.

This doesn't catch the following cases:

mount -f vol

zpool destroy -f tank

when I'm in /mnt/vol or /mnt/tank (this occurs on 8.0.3 as well and this is sort of by design as they're 'force' operations). This might be a noop, or something of concern.

This change -- along with r9317 and r9318 -- resolves the issue where one couldn't export volumes via the GUI, as explained in ticket # 1126.

Make mount -ru / explicit when modifying root's ssh key is done.

Put comment in the right spot.

Remove always False case, and refactor to be slightly more optimal.

add a method to sync a single disk with storage_disk (Disk) table

Set some defaults in case PBI's are missing the freenas file.

Force start|stop plugins.

Provide better diagnostic output when creating a home directory fails.

Add a safety belt to ensure that the user doesn't put his/her home directory under a subdirectory on the /mnt memory disk.

Make sure the nut daemons are dead. This closes a potential issue where nut stays up and running even after the service sliders claim things are off.