* [Cluster-devel] [GFS2 PATCH] GFS2: Only wait for demote when last holder is dequeued [not found] <279720953.1497814.1403271354163.JavaMail.zimbra@redhat.com> @ 2014-06-20 13:36 ` Bob Peterson 2014-06-20 14:18 ` Steven Whitehouse 0 siblings, 1 reply; 2+ messages in thread From: Bob Peterson @ 2014-06-20 13:36 UTC (permalink / raw) To: cluster-devel.redhat.com Hi, Function gfs2_glock_dq_wait is supposed to dequeue a glock and then wait for the lock to be demoted. The problem is, if this is a shared lock, its demote will depend on the other holders, which means you might end up waiting forever because the other process is blocked. This problem is especially apparent when dealing with nested flocks. Regards, Bob Peterson Red Hat File Systems Signed-off-by: Bob Peterson <rpeterso@redhat.com> --- diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index aec7f73..22ce2f0 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -1128,7 +1128,9 @@ void gfs2_glock_dq_wait(struct gfs2_holder *gh) struct gfs2_glock *gl = gh->gh_gl; gfs2_glock_dq(gh); might_sleep(); - wait_on_bit(&gl->gl_flags, GLF_DEMOTE, gfs2_glock_demote_wait, TASK_UNINTERRUPTIBLE); + if (!find_first_holder(gl)) + wait_on_bit(&gl->gl_flags, GLF_DEMOTE, gfs2_glock_demote_wait, + TASK_UNINTERRUPTIBLE); } /** ^ permalink raw reply related [flat|nested] 2+ messages in thread
* [Cluster-devel] [GFS2 PATCH] GFS2: Only wait for demote when last holder is dequeued 2014-06-20 13:36 ` [Cluster-devel] [GFS2 PATCH] GFS2: Only wait for demote when last holder is dequeued Bob Peterson @ 2014-06-20 14:18 ` Steven Whitehouse 0 siblings, 0 replies; 2+ messages in thread From: Steven Whitehouse @ 2014-06-20 14:18 UTC (permalink / raw) To: cluster-devel.redhat.com Hi, Now in the -nmw tree. Thanks, Steve. On 20/06/14 14:36, Bob Peterson wrote: > Hi, > > Function gfs2_glock_dq_wait is supposed to dequeue a glock and then > wait for the lock to be demoted. The problem is, if this is a shared > lock, its demote will depend on the other holders, which means you > might end up waiting forever because the other process is blocked. > This problem is especially apparent when dealing with nested flocks. > > Regards, > > Bob Peterson > Red Hat File Systems > > Signed-off-by: Bob Peterson <rpeterso@redhat.com> > --- > diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c > index aec7f73..22ce2f0 100644 > --- a/fs/gfs2/glock.c > +++ b/fs/gfs2/glock.c > @@ -1128,7 +1128,9 @@ void gfs2_glock_dq_wait(struct gfs2_holder *gh) > struct gfs2_glock *gl = gh->gh_gl; > gfs2_glock_dq(gh); > might_sleep(); > - wait_on_bit(&gl->gl_flags, GLF_DEMOTE, gfs2_glock_demote_wait, TASK_UNINTERRUPTIBLE); > + if (!find_first_holder(gl)) > + wait_on_bit(&gl->gl_flags, GLF_DEMOTE, gfs2_glock_demote_wait, > + TASK_UNINTERRUPTIBLE); > } > > /** > ^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2014-06-20 14:18 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
[not found] <279720953.1497814.1403271354163.JavaMail.zimbra@redhat.com>
2014-06-20 13:36 ` [Cluster-devel] [GFS2 PATCH] GFS2: Only wait for demote when last holder is dequeued Bob Peterson
2014-06-20 14:18 ` Steven Whitehouse
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.