[Nfs-ganesha-devel] Re: Question about operations between SAL <-> FSAL for locking
On 06/15/2018 06:39 AM, Tuan Viet Nguyen wrote:
Hello,
I'm trying to integrate a FS supporting async lock (can run callback
when a lock is granted) as ganesha FSAL. For the moment I do not make
any upcalls to FSAL and the lock still work. I wonder how it can work?
may be SAL handles that itself, does it have an internal lock queue and
tries/retries the waiting lock by making lock calls again frequently to
the FSAL to know when it can grant the lock?
Can somebody shed some light on that? And if it is the case, I imagine
that making the grant_lock upcall will increase the performance? Or
there are even more benefits?
Thank you
Viet
So, SAL won't grant locks itself, it always calls lock_op2() in the FSAL
to grant the lock. However, if there is a blocking lock, and the FSAL
doesn't support async locks, then it will keep track of the lock itself,
and whenever a lock is released, it will check to see if any blocked
locks are now unblocked, and if so call lock_op2() to grant those locks.
What does your FSAL set for fso_lock_support_async_block? What does
your lock_op2() return for a normal lock attempt?
Daniel