[Gluster-devel] Posix lock migration design

[Raghavendra G]

On Mon, Feb 29, 2016 at 12:52 PM, Susant Palai <spalai at redhat.com> wrote:

> Hi Raghavendra,
>    I have a question on the design.
>
>    Currently in case of a client disconnection, pl_flush cleans up the
> locks associated with the fd created from that client.
> From the design, rebalance will migrate the locks to the new destination.
> Now in case client gets disconnected from the
> destination brick, how it is supposed to clean up the locks as
> rebalance/brick have no idea whether the client has opened
> an fd on destination and what the fd is.
>

>    So the question is how to associate the client fd with locks on
> destination.
>

We don't use fds to cleanup the locks during flush. We use lk-owner which
doesn't change across migration. Note that lk-owner for posix-locks is
filled by the vfs/kernel where we've glusterfs mount.

<pl_flush>
         pthread_mutex_lock (&pl_inode->mutex);
        {
                __delete_locks_of_owner (pl_inode, frame->root->client,
                                         &frame->root->lk_owner);
        }
        pthread_mutex_unlock (&pl_inode->mutex);
</pl_flush>


> Thanks,
> Susant
>
> ----- Original Message -----
> From: "Susant Palai" <spalai at redhat.com>
> To: "Gluster Devel" <gluster-devel at gluster.org>
> Sent: Friday, 29 January, 2016 3:15:14 PM
> Subject: [Gluster-devel] Posix lock migration design
>
> Hi,
>    Here, [1]
>
> https://docs.google.com/document/d/17SZAKxx5mhM-cY5hdE4qRq9icmFqy3LBaTdewofOXYc/edit?usp=sharing
> is a google document about proposal for "POSIX_LOCK_MIGRATION". Problem
> statement and design are explained in the document it self.
>
>   Requesting the devel list to go through the document and
> comment/analyze/suggest, to take the thoughts forward (either on the
> google doc itself or here on the devel list).
>
>
> Thanks,
> Susant
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-- 
Raghavendra G
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