On Wed, 2017-04-05 at 09:30 +0800, Yan, Zheng wrote:
> __unregister_session() free the session if it drops the last
> reference. We should grab an extra reference if we want to use
> session after __unregister_session().
>
> Signed-off-by: "Yan, Zheng" <zyan@xxxxxxxxxx>
> ---
> fs/ceph/mds_client.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> index 163f0d3..bf765a8 100644
> --- a/fs/ceph/mds_client.c
> +++ b/fs/ceph/mds_client.c
> @@ -2658,8 +2658,10 @@ static void handle_session(struct ceph_mds_session *session,
> seq = le64_to_cpu(h->seq);
>
> mutex_lock(&mdsc->mutex);
> - if (op == CEPH_SESSION_CLOSE)
> + if (op == CEPH_SESSION_CLOSE) {
> + get_session(session);
> __unregister_session(mdsc, session);
> + }
> /* FIXME: this ttl calculation is generous */
> session->s_ttl = jiffies + HZ*mdsc->mdsmap->m_session_autoclose;
> mutex_unlock(&mdsc->mutex);
> @@ -2748,6 +2750,8 @@ static void handle_session(struct ceph_mds_session *session,
> kick_requests(mdsc, mds);
> mutex_unlock(&mdsc->mutex);
> }
> + if (op == CEPH_SESSION_CLOSE)
> + ceph_put_mds_session(session);
> return;
>
> bad:
> @@ -3148,8 +3152,10 @@ static void check_new_map(struct ceph_mds_client *mdsc,
> if (s->s_state == CEPH_MDS_SESSION_OPENING) {
> /* the session never opened, just close it
> * out now */
> - __wake_requests(mdsc, &s->s_waiting);
> + get_session(s);
> __unregister_session(mdsc, s);
> + __wake_requests(mdsc, &s->s_waiting);
> + ceph_put_mds_session(s);
What about this last bit? Why do we need to __wake_requests after
__unregister_session here? If not for that change then you wouldn't
need to take the extra reference here, AFAICS.
> } else {
> /* just close it */
> mutex_unlock(&mdsc->mutex);
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
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