2012/7/27 Jeff Layton <jlayton@xxxxxxxxxx>:
> On Fri, 27 Jul 2012 03:57:44 +0400
> Pavel Shilovsky <piastryyy@xxxxxxxxx> wrote:
>
>> 2012/7/25 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.
>> >
>> > Acked-by: Pavel Shilovsky <pshilovsky@xxxxxxxxx>
>> > 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 6df6fa1..a828a8c 100644
>> > --- a/fs/cifs/connect.c
>> > +++ b/fs/cifs/connect.c
>> > @@ -1676,6 +1676,10 @@ 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 d93f15d..a3e58b2 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>
>> > @@ -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);
>> > --
>> > 1.7.11.2
>> >
>> > --
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>>
>> I tested it with SMB2 against Windows 7 server. When iosize is 64K
>> everything is ok but when we increase iosize to 1M (by using
>> multicredit requests) and the server loses the network connection and
>> only reboot helps.
>>
>> Also if I commented corking/uncorking the socket - everything is ok. I
>> think this change needs some more investigation (how does it deals
>> with 1M iosize on Samba, etc?)
>>
>
> Hmm, haven't seen that with a 1M iosize with smb1 against samba.
>
> I'll see if I can reproduce it.
>
> --
> Jeff Layton <jlayton@xxxxxxxxxx>
Forgot to mentioned how I reproduce it - dbench with 5 clients.
--
Best regards,
Pavel Shilovsky.
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