umount -f

[Modulok]

Couple questions for anyone on the list who has a moment (and the answer to
any of these):

Objective: I need to kick people off of a storage drive (we'll say
/dev/ad4), without corrupting the file system and without bringing the
entire system down. I need to safely umount the file systems, even if my
users have processes which have files open.

1. If I use "umount -f /dev/ad4s1a" to forcefully umount a file system, does
this jeopardize the integrity of said file system? Like...will it jerk the
run out from under a process in the middle of a disk write, thus leaving a
half written file, or will it wait until the write is complete? (I guess
this would largely depend on the disk controller?)

2. How do I get a list of processes that are accessing a specific file
system, e.g. /dev/ad4s1a?

3. Is there any safe way to unconditionally umount a file system, even if a
run-away process is writing to it (as bad of an idea as this is)?

Thanks.
-Modulok-