From mboxrd@z Thu Jan 1 00:00:00 1970 From: Long Li Subject: [PATCH 1/2] cifs: smbd: avoid reconnect lockup Date: Fri, 30 Mar 2018 15:16:35 -0700 Message-ID: <20180330221636.32512-1-longli@linuxonhyperv.com> Reply-To: longli@microsoft.com Cc: Long Li To: Steve French , linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, linux-kernel@vger.kernel.org Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-cifs.vger.kernel.org From: Long Li During transport reconnect, other processes may have registered memory and blocked on transport. This creates a deadlock situation because the transport resources can't be freed, and reconnect is blocked. Fix this by returning to upper layer on timeout. Before returning, transport status is set to reconnecting so other processes will release memory registration resources. Upper layer will retry the reconnect. This is not in fast I/O path so setting the timeout to 5 seconds. Signed-off-by: Long Li --- fs/cifs/smbdirect.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/fs/cifs/smbdirect.c b/fs/cifs/smbdirect.c index 5aa0b54..3f7883e 100644 --- a/fs/cifs/smbdirect.c +++ b/fs/cifs/smbdirect.c @@ -1498,8 +1498,8 @@ int smbd_reconnect(struct TCP_Server_Info *server) log_rdma_event(INFO, "reconnecting rdma session\n"); if (!server->smbd_conn) { - log_rdma_event(ERR, "rdma session already destroyed\n"); - return -EINVAL; + log_rdma_event(INFO, "rdma session already destroyed\n"); + goto create_conn; } /* @@ -1512,15 +1512,19 @@ int smbd_reconnect(struct TCP_Server_Info *server) } /* wait until the transport is destroyed */ - wait_event(server->smbd_conn->wait_destroy, - server->smbd_conn->transport_status == SMBD_DESTROYED); + if (!wait_event_timeout(server->smbd_conn->wait_destroy, + server->smbd_conn->transport_status == SMBD_DESTROYED, 5*HZ)) + return -EAGAIN; destroy_workqueue(server->smbd_conn->workqueue); kfree(server->smbd_conn); +create_conn: log_rdma_event(INFO, "creating rdma session\n"); server->smbd_conn = smbd_get_connection( server, (struct sockaddr *) &server->dstaddr); + log_rdma_event(INFO, "created rdma session info=%p\n", + server->smbd_conn); return server->smbd_conn ? 0 : -ENOENT; } -- 2.7.4