Commit b8eed283 authored by Jeff Layton's avatar Jeff Layton Committed by Steve French
Browse files

cifs: cork the socket before a send and uncork it afterward 



We want to send SMBs as "atomically" as possible. Prior to sending any
data on the socket, cork it to make sure that no non-full frames go
out. Afterward, uncork it to make sure all of the data gets pushed out
to the wire.

Note that this more or less renders the socket=TCP_NODELAY mount option
obsolete. When TCP_CORK and TCP_NODELAY are used on the same socket,
TCP_NODELAY is essentially ignored.

Acked-by: default avatarPavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarSteve French <smfrench@gmail.com>
parent 6f49f46b

fs/cifs/connect.c

+4 −0
Original line number Diff line number Diff line
@@ -1680,6 +1680,10 @@ cifs_parse_mount_options(const char *mountdata, const char *devname, 
			if (string == NULL)

				goto out_nomem;



			/*

			 * FIXME: since we now cork/uncork the socket while

			 * 	  sending, should we deprecate this option?

			 */

			if (strnicmp(string, "TCP_NODELAY", 11) == 0)

				vol->sockopt_tcp_nodelay = 1;

			break;

fs/cifs/transport.c

+12 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <linux/net.h>

#include <linux/delay.h>

#include <linux/freezer.h>

#include <linux/tcp.h>

#include <asm/uaccess.h>

#include <asm/processor.h>

#include <linux/mempool.h>
@@ -247,12 +248,23 @@ smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst) 
	int n_vec = rqst->rq_nvec;

	unsigned int smb_buf_length = get_rfc1002_length(iov[0].iov_base);

	size_t total_len;

	struct socket *ssocket = server->ssocket;

	int val = 1;



	cFYI(1, "Sending smb: smb_len=%u", smb_buf_length);

	dump_smb(iov[0].iov_base, iov[0].iov_len);



	/* cork the socket */

	kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK,

				(char *)&val, sizeof(val));



	rc = smb_send_kvec(server, iov, n_vec, &total_len);



	/* uncork it */

	val = 0;

	kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK,

				(char *)&val, sizeof(val));



	if ((total_len > 0) && (total_len != smb_buf_length + 4)) {

		cFYI(1, "partial send (wanted=%u sent=%zu): terminating "

			"session", smb_buf_length + 4, total_len);

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