From 8a856fdede1669cbaeadeea87fc5b2ac071cee1b Mon Sep 17 00:00:00 2001 From: Alexander Aring Date: Tue, 29 Apr 2025 16:29:10 -0400 Subject: dlm: mask sk_shutdown value The sk->sk_shutdown value is flag value so use masking to check if RCV_SHUTDOWN is set as other possible values like SEND_SHUTDOWN can set as well. Signed-off-by: Alexander Aring Tested-by: Heming zhao Reviewed-by: Heming zhao Signed-off-by: David Teigland --- fs/dlm/lowcomms.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c index 70abd4da17a6..50c42b368c83 100644 --- a/fs/dlm/lowcomms.c +++ b/fs/dlm/lowcomms.c @@ -533,7 +533,7 @@ static void lowcomms_state_change(struct sock *sk) /* SCTP layer is not calling sk_data_ready when the connection * is done, so we catch the signal through here. */ - if (sk->sk_shutdown == RCV_SHUTDOWN) + if (sk->sk_shutdown & RCV_SHUTDOWN) lowcomms_data_ready(sk); } -- cgit v1.2.3-59-g8ed1b From 55612ddb62fc12437a7ff2f27b51a8981bc187a4 Mon Sep 17 00:00:00 2001 From: Alexander Aring Date: Tue, 29 Apr 2025 16:29:11 -0400 Subject: dlm: use SHUT_RDWR for SCTP shutdown Currently SCTP shutdown() call gets stuck because there is no incoming EOF indicator on its socket. On the peer side the EOF indicator as recvmsg() returns 0 will be triggered as mechanism to flush the socket queue on the receive side. In SCTP recvmsg() function sctp_recvmsg() we can see that only if sk_shutdown has the bit RCV_SHUTDOWN set SCTP will recvmsg() will return EOF. The RCV_SHUTDOWN bit will only be set when shutdown with SHUT_RD is called. We use now SHUT_RDWR to also get a EOF indicator from recvmsg() call on the shutdown() initiator. SCTP does not support half closed sockets and the semantic of SHUT_WR is different here, it seems that calling SHUT_WR on sctp sockets keeps the socket open to have the possibility to do some specific SCTP operations on it that we don't do here. There exists still a difference in the limitations of TCP vs SCTP in case if we are required to have a half closed socket functionality. This was tried to archieve with DLM protocol changes in the past and hopefully we really don't require half closed socket functionality. Signed-off-by: Alexander Aring Tested-by: Heming zhao Reviewed-by: Heming zhao Signed-off-by: David Teigland --- fs/dlm/lowcomms.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c index 50c42b368c83..e4373bce1bc2 100644 --- a/fs/dlm/lowcomms.c +++ b/fs/dlm/lowcomms.c @@ -160,6 +160,7 @@ struct dlm_proto_ops { bool try_new_addr; const char *name; int proto; + int how; void (*sockopts)(struct socket *sock); int (*bind)(struct socket *sock); @@ -810,7 +811,7 @@ static void shutdown_connection(struct connection *con, bool and_other) return; } - ret = kernel_sock_shutdown(con->sock, SHUT_WR); + ret = kernel_sock_shutdown(con->sock, dlm_proto_ops->how); up_read(&con->sock_lock); if (ret) { log_print("Connection %p failed to shutdown: %d will force close", @@ -1858,6 +1859,7 @@ static int dlm_tcp_listen_bind(struct socket *sock) static const struct dlm_proto_ops dlm_tcp_ops = { .name = "TCP", .proto = IPPROTO_TCP, + .how = SHUT_WR, .sockopts = dlm_tcp_sockopts, .bind = dlm_tcp_bind, .listen_validate = dlm_tcp_listen_validate, @@ -1896,6 +1898,7 @@ static void dlm_sctp_sockopts(struct socket *sock) static const struct dlm_proto_ops dlm_sctp_ops = { .name = "SCTP", .proto = IPPROTO_SCTP, + .how = SHUT_RDWR, .try_new_addr = true, .sockopts = dlm_sctp_sockopts, .bind = dlm_sctp_bind, -- cgit v1.2.3-59-g8ed1b From 574511615a2e17e5dfe4754f6e9cea005b6c718a Mon Sep 17 00:00:00 2001 From: Alexander Aring Date: Tue, 29 Apr 2025 16:29:12 -0400 Subject: dlm: reject SCTP configuration if not enabled Reject SCTP dlm configuration if the kernel was never build with SCTP. Currently the only one known user space tool "dlm_controld" will drop an error in the logs and getting stuck. This behaviour should be fixed to deliver an error to the user or fallback to TCP. Signed-off-by: Alexander Aring Reviewed-by: Heming zhao Signed-off-by: David Teigland --- fs/dlm/config.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/dlm/config.c b/fs/dlm/config.c index cf9ba6fd7a28..a23fd524a6ee 100644 --- a/fs/dlm/config.c +++ b/fs/dlm/config.c @@ -197,6 +197,9 @@ static int dlm_check_protocol_and_dlm_running(unsigned int x) break; case 1: /* SCTP */ + if (!IS_ENABLED(CONFIG_IP_SCTP)) + return -EOPNOTSUPP; + break; default: return -EINVAL; -- cgit v1.2.3-59-g8ed1b From 6f8b4788266c7df3b7cfc6c665f663b4c3d09aad Mon Sep 17 00:00:00 2001 From: Alexander Aring Date: Tue, 29 Apr 2025 16:29:13 -0400 Subject: dlm: drop SCTP Kconfig dependency DLM does not use any exported SCTP function. SCTP is registered dynamically as protocol to the kernel and can be used over the right protocol identifiers on the socket api. We drop the SCTP dependency as DLM can also be used with TCP only. Signed-off-by: Alexander Aring Reviewed-by: Heming zhao Signed-off-by: David Teigland --- fs/dlm/Kconfig | 1 - 1 file changed, 1 deletion(-) diff --git a/fs/dlm/Kconfig b/fs/dlm/Kconfig index f82a4952769d..b46165df5a91 100644 --- a/fs/dlm/Kconfig +++ b/fs/dlm/Kconfig @@ -3,7 +3,6 @@ menuconfig DLM tristate "Distributed Lock Manager (DLM)" depends on INET depends on SYSFS && CONFIGFS_FS && (IPV6 || IPV6=n) - select IP_SCTP help A general purpose distributed lock manager for kernel or userspace applications. -- cgit v1.2.3-59-g8ed1b