linux.git/fs/dlm/lowcomms.c, branch v5.9

fs: dlm: implement tcp graceful shutdown

2020-08-06T15:30:54+00:00

During my code inspection I saw there is no implementation of a graceful
shutdown for tcp. This patch will introduce a graceful shutdown for tcp
connections. The shutdown is implemented synchronized as
dlm_lowcomms_stop() is called to end all dlm communication. After shutdown
is done, a lot of flush and closing functionality will be called. However
I don't see a problem with that.

The waitqueue for synchronize the shutdown has a timeout of 10 seconds, if
timeout a force close will be exectued.

Signed-off-by: Alexander Aring 
Signed-off-by: David Teigland

fs: dlm: change handling of reconnects

2020-08-06T15:30:54+00:00

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 
Signed-off-by: David Teigland

fs: dlm: don't close socket on invalid message

2020-08-06T15:30:53+00:00

This patch doesn't close sockets when there is an invalid dlm message
received. The connection will probably reconnect anyway so. To not
close the connection will reduce the number of possible failtures.
As we don't have a different strategy to react on such scenario
just keep going the connection and ignore the message.

Signed-off-by: Alexander Aring 
Signed-off-by: David Teigland

fs: dlm: set skb mark per peer socket

2020-08-06T15:30:52+00:00

This patch adds support to set the skb mark value for the DLM tcp and
sctp socket per peer. The mark value will be offered as per comm value
of configfs. At creation time of the peer socket it will be set as
socket option.

Signed-off-by: Alexander Aring 
Signed-off-by: David Teigland

fs: dlm: set skb mark for listen socket

2020-08-06T15:30:51+00:00

This patch adds support to set the skb mark value for the DLM listen
tcp and sctp sockets. The mark value will be offered as cluster
configuration. At creation time of the listen socket it will be set as
socket option.

Signed-off-by: Alexander Aring 
Signed-off-by: David Teigland

net: add a new bind_add method

2020-05-29T20:10:39+00:00

The SCTP protocol allows to bind multiple address to a socket.  That
feature is currently only exposed as a socket option.  Add a bind_add
method struct proto that allows to bind additional addresses, and
switch the dlm code to use the method instead of going through the
socket option from kernel space.

Signed-off-by: Christoph Hellwig 
Acked-by: Marcelo Ricardo Leitner 
Signed-off-by: David S. Miller

sctp: add sctp_sock_set_nodelay

2020-05-29T20:10:39+00:00

Add a helper to directly set the SCTP_NODELAY sockopt from kernel space
without going through a fake uaccess.

Signed-off-by: Christoph Hellwig 
Acked-by: Marcelo Ricardo Leitner 
Signed-off-by: David S. Miller

tcp: add tcp_sock_set_nodelay

2020-05-28T18:11:45+00:00

Add a helper to directly set the TCP_NODELAY sockopt from kernel space
without going through a fake uaccess.  Cleanup the callers to avoid
pointless wrappers now that this is a simple function call.

Signed-off-by: Christoph Hellwig 
Acked-by: Sagi Grimberg 
Acked-by: Jason Gunthorpe 
Signed-off-by: David S. Miller

net: add sock_set_rcvbuf

2020-05-28T18:11:44+00:00

Add a helper to directly set the SO_RCVBUFFORCE sockopt from kernel space
without going through a fake uaccess.

Signed-off-by: Christoph Hellwig 
Signed-off-by: David S. Miller

net: add sock_set_keepalive

2020-05-28T18:11:44+00:00

Add a helper to directly set the SO_KEEPALIVE sockopt from kernel space
without going through a fake uaccess.

Signed-off-by: Christoph Hellwig 
Signed-off-by: David S. Miller