cluster/afr: serialize inode locks

      Backport of http://review.gluster.com/9372

Problem:
Afr winds inodelk calls without any order, so blocking inodelks
from two different mounts can lead to dead lock when mount1 gets
the lock on brick-1 and blocked on brick-2 where as mount2 gets
lock on brick-2 and blocked on brick-1

Fix:
Serialize the inodelks whether they are blocking inodelks or
non-blocking inodelks.

        Non-blocking locks also need to be serialized.
Otherwise there is a chance that both the mounts which issued same
non-blocking inodelk may endup not acquiring the lock on any-brick.
Ex:
Mount1 and Mount2 request for full length lock on file f1.  Mount1 afr may
acquire the partial lock on brick-1 and may not acquire the lock on brick-2
because Mount2 already got the lock on brick-2, vice versa. Since both the
mounts only got partial locks, afr treats them as failure in gaining the locks
and unwinds with EAGAIN errno.

Change-Id: I939a1d101e313a9f0abf212b94cdce1392611a5e
BUG: 1177928
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/9374
Reviewed-by: Krutika Dhananjay <kdhananj@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Niels de Vos <ndevos@redhat.com>

0 files changed, 0 insertions, 0 deletions