posix/lock: implement meta-lock/unlock functionality

problem : The lock state needs to be protected when rebalance is reading the
lock state on the source. Otherwise there will be locks left unmigrated.
Hence, to synchronize incoming lock requests with lock-migration, meta lock
is needed. Any new lock request will be queued if there is an active meta-lock
and with sucessful lock migration, will be unwound with EREMOTE, so that
dht module can wind the request to the correct destination.

On a successful lock migration, "pl_inode->migrated" flag is enabled. Hence,
any further request would be unwound with EREMOTE and will be redirected to
new destination.

More details can be found here:
https://github.com/gluster/glusterfs-specs/blob/master/accepted/Lock-Migration.md

design discussion:
https://www.gluster.org/pipermail/gluster-devel/2016-January/048088.html

Change-Id: Ief033d5652b5ca4ba6f499110a521cae283d6aba
BUG: 1338501
Signed-off-by: Susant Palai <spalai@redhat.com>
Reviewed-on: http://review.gluster.org/14462
Tested-by: Kotresh HR <khiremat@redhat.com>
Smoke: Gluster Build System <jenkins@build.gluster.com>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
Reviewed-by: Raghavendra G <rgowdapp@redhat.com>
CentOS-regression: Gluster Build System <jenkins@build.gluster.com>

0 files changed, 0 insertions, 0 deletions