2012/7/18 Jeff Layton <jlayton@xxxxxxxxxx>:
> 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.
>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> fs/cifs/connect.c | 4 ++++
> fs/cifs/transport.c | 12 ++++++++++++
> 2 files changed, 16 insertions(+)
>
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index e8c3e6b..99ca139 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -1830,6 +1830,10 @@ 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;
> diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
> index 5a1d817..af56e91 100644
> --- a/fs/cifs/transport.c
> +++ b/fs/cifs/transport.c
> @@ -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>
> @@ -248,12 +249,23 @@ 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);
> --
> 1.7.10.4
>
> --
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Acked-by: Pavel Shilovsky <pshilovsky@xxxxxxxxx>
--
Best regards,
Pavel Shilovsky.
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