On 05 Nov 2014 21:22:56 +0100 bstroesser@xxxxxxxxxxxxxx wrote:
> From: Bodo Stroesser <bstroesser@xxxxxxxxxxxxxx>
> Date: Thu, 09 Oct 2014 13:06:19 +0200
> Subject: [nfs-utils] [PATCH 1/3] rpc.mountd: set nonblocking mode if no libtirpc
>
> If mountd is built without libtirpc and it is started using "-p XXX" option,
> the tcp listeners and the sockets waiting for UDP messages are not in
> non-blocking mode. Thus if running with multiple threads (-t XX),
> all threads will wake up from select on a connection request or a UDP message,
> but only one thread will succeed. All others will wait on accept() or read()
> for the next event.
>
> Signed-off-by: Bodo Stroesser <bstroesser@xxxxxxxxxxxxxx>
> ---
Reviewed-by: NeilBrown <neilb@xxxxxxx>
This is just taking the code that already applies in svc_socket() when no
explicit port number is requested, and applying it also in makesock() which
is used when an explicit port number *is* requested.
Thanks,
NeilBrown
>
> --- nfs-utils-1.3.1/support/include/nfslib.h 2014-10-09 12:52:30.000000000 +0200
> +++ nfs-utils-1.3.1/support/include/nfslib.h 2014-10-09 12:53:37.000000000 +0200
> @@ -174,6 +174,7 @@ void closeall(int min);
>
> int svctcp_socket (u_long __number, int __reuse);
> int svcudp_socket (u_long __number);
> +int svcsock_nonblock (int __sock);
>
> /* Misc shared code prototypes */
> size_t strlcat(char *, const char *, size_t);
> --- nfs-utils-1.3.1/support/nfs/svc_socket.c 2014-10-09 12:56:14.000000000 +0200
> +++ nfs-utils-1.3.1/support/nfs/svc_socket.c 2014-10-09 13:10:44.000000000 +0200
> @@ -76,6 +76,39 @@ int getservport(u_long number, const cha
> return 0;
> }
>
> +int
> +svcsock_nonblock(int sock)
> +{
> + int flags;
> +
> + if (sock < 0)
> + return sock;
> +
> + /* This socket might be shared among multiple processes
> + * if mountd is run multi-threaded. So it is safest to
> + * make it non-blocking, else all threads might wake
> + * one will get the data, and the others will block
> + * indefinitely.
> + * In all cases, transaction on this socket are atomic
> + * (accept for TCP, packet-read and packet-write for UDP)
> + * so O_NONBLOCK will not confuse unprepared code causing
> + * it to corrupt messages.
> + * It generally safest to have O_NONBLOCK when doing an accept
> + * as if we get a RST after the SYN and before accept runs,
> + * we can block despite being told there was an acceptable
> + * connection.
> + */
> + if ((flags = fcntl(sock, F_GETFL)) < 0)
> + perror(_("svc_socket: can't get socket flags"));
> + else if (fcntl(sock, F_SETFL, flags|O_NONBLOCK) < 0)
> + perror(_("svc_socket: can't set socket flags"));
> + else
> + return sock;
> +
> + (void) __close(sock);
> + return -1;
> +}
> +
> static int
> svc_socket (u_long number, int type, int protocol, int reuse)
> {
> @@ -113,38 +146,7 @@ svc_socket (u_long number, int type, int
> sock = -1;
> }
>
> - if (sock >= 0)
> - {
> - /* This socket might be shared among multiple processes
> - * if mountd is run multi-threaded. So it is safest to
> - * make it non-blocking, else all threads might wake
> - * one will get the data, and the others will block
> - * indefinitely.
> - * In all cases, transaction on this socket are atomic
> - * (accept for TCP, packet-read and packet-write for UDP)
> - * so O_NONBLOCK will not confuse unprepared code causing
> - * it to corrupt messages.
> - * It generally safest to have O_NONBLOCK when doing an accept
> - * as if we get a RST after the SYN and before accept runs,
> - * we can block despite being told there was an acceptable
> - * connection.
> - */
> - int flags;
> - if ((flags = fcntl(sock, F_GETFL)) < 0)
> - {
> - perror (_("svc_socket: can't get socket flags"));
> - (void) __close (sock);
> - sock = -1;
> - }
> - else if (fcntl(sock, F_SETFL, flags|O_NONBLOCK) < 0)
> - {
> - perror (_("svc_socket: can't set socket flags"));
> - (void) __close (sock);
> - sock = -1;
> - }
> - }
> -
> - return sock;
> + return svcsock_nonblock(sock);
> }
>
> /*
> --- nfs-utils-1.3.1/support/nfs/rpcmisc.c 2014-10-08 21:22:04.000000000 +0200
> +++ nfs-utils-1.3.1/support/nfs/rpcmisc.c 2014-10-08 21:22:36.000000000 +0200
> @@ -104,7 +104,7 @@ makesock(int port, int proto)
> return -1;
> }
>
> - return sock;
> + return svcsock_nonblock(sock);
> }
>
> void
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