tree 474e8c3bda161953202793c0801ab00a5b5433de
parent 1ad38c437fa33f85ba4b6a85ea8c5478ee72d5bd
author Abhijith Das <adas@redhat.com> 1189744527 -0500
committer Steven Whitehouse <swhiteho@redhat.com> 1192002974 +0100

[GFS2] flocks from same process trip kernel BUG at fs/gfs2/glock.c:1118!

This patch adds a new flag to the gfs2_holder structure GL_FLOCK.
It is set on holders of glocks representing flocks. This flag is
checked in add_to_queue() and a process is permitted to queue more
than one holder onto a glock if it is set. This solves the issue
of a process not being able to do multiple flocks on the same file.
Through a single descriptor, a process can now promote and demote
flocks. Through multiple descriptors a process can now queue
multiple flocks on the same file. There's still the problem of
a process deadlocking itself (because gfs2 blocking locks are not
interruptible) by queueing incompatible deadlock.

Signed-off-by: Abhijith Das <adas@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>