diff options
author | Alexander Aring <aahringo@redhat.com> | 2020-07-27 09:13:37 -0400 |
---|---|---|
committer | David Teigland <teigland@redhat.com> | 2020-08-06 10:30:54 -0500 |
commit | ba3ab3ca68caafb7700c4abae357b7fb7538df11 (patch) | |
tree | fc015a963ac2faacbb524eb66ea088d7a7cf8a53 /fs | |
parent | 0ea47e4d2109efd61e9949d014b37ea835f20861 (diff) |
fs: dlm: change handling of reconnects
This patch changes the handling of reconnects. At first we only close
the connection related to the communication failure. If we get a new
connection for an already existing connection we close the existing
connection and take the new one.
This patch improves significantly the stability of tcp connections while
running "tcpkill -9 -i $IFACE port 21064" while generating a lot of dlm
messages e.g. on a gfs2 mount with many files. My test setup shows that a
deadlock is "more" unlikely. Before this patch I wasn't able to get
not a deadlock after 5 seconds. After this patch my observation is
that it's more likely to survive after 5 seconds and more, but still a
deadlock occurs after certain time. My guess is that there are still
"segments" inside the tcp writequeue or retransmit queue which get dropped
when receiving a tcp reset [1]. Hard to reproduce because the right message
need to be inside these queues, which might even be in the 5 first seconds
with this patch.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/ipv4/tcp_input.c?h=v5.8-rc6#n4122
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/dlm/lowcomms.c | 25 |
1 files changed, 10 insertions, 15 deletions
diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c index 9e6acbb47bb9..289439fdca99 100644 --- a/fs/dlm/lowcomms.c +++ b/fs/dlm/lowcomms.c @@ -713,7 +713,7 @@ out_resched: out_close: mutex_unlock(&con->sock_mutex); if (ret != -EAGAIN) { - close_connection(con, true, true, false); + close_connection(con, false, true, false); /* Reconnect when there is something to send */ } /* Don't return success if we really got EOF */ @@ -804,21 +804,16 @@ static int accept_from_sock(struct connection *con) INIT_WORK(&othercon->swork, process_send_sockets); INIT_WORK(&othercon->rwork, process_recv_sockets); set_bit(CF_IS_OTHERCON, &othercon->flags); + } else { + /* close other sock con if we have something new */ + close_connection(othercon, false, true, false); } + mutex_lock_nested(&othercon->sock_mutex, 2); - if (!othercon->sock) { - newcon->othercon = othercon; - add_sock(newsock, othercon); - addcon = othercon; - mutex_unlock(&othercon->sock_mutex); - } - else { - printk("Extra connection from node %d attempted\n", nodeid); - result = -EAGAIN; - mutex_unlock(&othercon->sock_mutex); - mutex_unlock(&newcon->sock_mutex); - goto accept_err; - } + newcon->othercon = othercon; + add_sock(newsock, othercon); + addcon = othercon; + mutex_unlock(&othercon->sock_mutex); } else { newcon->rx_action = receive_from_sock; @@ -1415,7 +1410,7 @@ out: send_error: mutex_unlock(&con->sock_mutex); - close_connection(con, true, false, true); + close_connection(con, false, false, true); /* Requeue the send work. When the work daemon runs again, it will try a new connection, then call this function again. */ queue_work(send_workqueue, &con->swork); |