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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: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
hifive-unleashed-5.1
Jeff Layton 2012-09-18 16:20:35 -07:00 committed by Steve French
parent 6f49f46b18
commit b8eed28375
2 changed files with 16 additions and 0 deletions
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4
fs/cifs/connect.c
View File

@ -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;

12
fs/cifs/transport.c
View File

@ -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);