[Devel] Re: [PATCH] Wake up mandatory locks waiter on chmod (v2)

[Trond Myklebust]

On Mon, 2007-09-17 at 12:13 +0400, Pavel Emelyanov wrote:
> When the process is blocked on mandatory lock and someone changes 
> the inode's permissions, so that the lock is no longer mandatory,
> nobody wakes up the blocked process, but probably should.

Please explain in more detail why we need this patch.

I don't see why changing a file from taking mandatory locks to advisory
locks is really a useful operation that we need to support. For one
thing, we don't support changing a file from using advisory locking to
mandatory locking on-the-fly. Secondly, changing the locking type
certainly isn't a documented operation and quite frankly, it doesn't
even appear to make sense: if the file needs mandatory locking, then
that means that you have a need to protect against some untrusted
application that isn't following the locking rules. Then suddenly, you
declare that you will trust that application after all???

Cheers,
  Trond