| From b4002173b7989588b6feaefc42edaf011b596782 Mon Sep 17 00:00:00 2001 |
| From: Jeff Layton <jlayton@kernel.org> |
| Date: Tue, 27 Jul 2021 15:47:12 -0400 |
| Subject: ceph: cancel delayed work instead of flushing on mdsc teardown |
| |
| From: Jeff Layton <jlayton@kernel.org> |
| |
| commit b4002173b7989588b6feaefc42edaf011b596782 upstream. |
| |
| The first thing metric_delayed_work does is check mdsc->stopping, |
| and then return immediately if it's set. That's good since we would |
| have already torn down the metric structures at this point, otherwise, |
| but there is no locking around mdsc->stopping. |
| |
| It's possible that the ceph_metric_destroy call could race with the |
| delayed_work, in which case we could end up with the delayed_work |
| accessing destroyed percpu variables. |
| |
| At this point in the mdsc teardown, the "stopping" flag has already been |
| set, so there's no benefit to flushing the work. Move the work |
| cancellation in ceph_metric_destroy ahead of the percpu variable |
| destruction, and eliminate the flush_delayed_work call in |
| ceph_mdsc_destroy. |
| |
| Fixes: 18f473b384a6 ("ceph: periodically send perf metrics to MDSes") |
| Signed-off-by: Jeff Layton <jlayton@kernel.org> |
| Reviewed-by: Xiubo Li <xiubli@redhat.com> |
| Signed-off-by: Ilya Dryomov <idryomov@gmail.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| fs/ceph/mds_client.c | 1 - |
| fs/ceph/metric.c | 4 ++-- |
| 2 files changed, 2 insertions(+), 3 deletions(-) |
| |
| --- a/fs/ceph/mds_client.c |
| +++ b/fs/ceph/mds_client.c |
| @@ -4912,7 +4912,6 @@ void ceph_mdsc_destroy(struct ceph_fs_cl |
| |
| ceph_metric_destroy(&mdsc->metric); |
| |
| - flush_delayed_work(&mdsc->metric.delayed_work); |
| fsc->mdsc = NULL; |
| kfree(mdsc); |
| dout("mdsc_destroy %p done\n", mdsc); |
| --- a/fs/ceph/metric.c |
| +++ b/fs/ceph/metric.c |
| @@ -302,6 +302,8 @@ void ceph_metric_destroy(struct ceph_cli |
| if (!m) |
| return; |
| |
| + cancel_delayed_work_sync(&m->delayed_work); |
| + |
| percpu_counter_destroy(&m->total_inodes); |
| percpu_counter_destroy(&m->opened_inodes); |
| percpu_counter_destroy(&m->i_caps_mis); |
| @@ -309,8 +311,6 @@ void ceph_metric_destroy(struct ceph_cli |
| percpu_counter_destroy(&m->d_lease_mis); |
| percpu_counter_destroy(&m->d_lease_hit); |
| |
| - cancel_delayed_work_sync(&m->delayed_work); |
| - |
| ceph_put_mds_session(m->session); |
| } |
| |
