2012/7/18 Jeff Layton <jlayton@xxxxxxxxxx>:
> Again, just a change in the arguments and some function renaming here.
> In later patches, we'll change this code to deal with page arrays.
>
> In this patch, we add a new smb_send_rqst wrapper and have smb_sendv
> call that. Then we move most of the existing smb_sendv code into a new
> function -- smb_send_kvec. This seems a little redundant, but later
> we'll flesh this out to deal with arrays of pages.
>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> fs/cifs/transport.c | 135 ++++++++++++++++++++++++++++++++++-----------------
> 1 file changed, 90 insertions(+), 45 deletions(-)
>
> diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
> index 531da42..5a1d817 100644
> --- a/fs/cifs/transport.c
> +++ b/fs/cifs/transport.c
> @@ -120,18 +120,29 @@ delete_mid(struct mid_q_entry *mid)
> DeleteMidQEntry(mid);
> }
>
> +/*
> + * smb_send_kvec - send an array of kvecs to the server
> + * @server: Server to send the data to
> + * @iov: Pointer to array of kvecs
> + * @n_vec: length of kvec array
> + * @sent: amount of data sent on socket is stored here
> + *
> + * Our basic "send data to server" function. Should be called with srv_mutex
> + * held. The caller is responsible for handling the results.
> + */
> static int
> -smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
> +smb_send_kvec(struct TCP_Server_Info *server, struct kvec *iov, size_t n_vec,
> + size_t *sent)
> {
> int rc = 0;
> int i = 0;
> struct msghdr smb_msg;
> - unsigned int len = iov[0].iov_len;
> - unsigned int total_len;
> - int first_vec = 0;
> - unsigned int smb_buf_length = get_rfc1002_length(iov[0].iov_base);
> + unsigned int remaining;
> + size_t first_vec = 0;
> struct socket *ssocket = server->ssocket;
>
> + *sent = 0;
> +
> if (ssocket == NULL)
> return -ENOTSOCK; /* BB eventually add reconnect code here */
>
> @@ -144,56 +155,60 @@ smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
> else
> smb_msg.msg_flags = MSG_NOSIGNAL;
>
> - total_len = 0;
> + remaining = 0;
> for (i = 0; i < n_vec; i++)
> - total_len += iov[i].iov_len;
> -
> - cFYI(1, "Sending smb: total_len %d", total_len);
> - dump_smb(iov[0].iov_base, len);
> + remaining += iov[i].iov_len;
>
> i = 0;
> - while (total_len) {
> + while (remaining) {
> + /*
> + * If blocking send, we try 3 times, since each can block
> + * for 5 seconds. For nonblocking we have to try more
> + * but wait increasing amounts of time allowing time for
> + * socket to clear. The overall time we wait in either
> + * case to send on the socket is about 15 seconds.
> + * Similarly we wait for 15 seconds for a response from
> + * the server in SendReceive[2] for the server to send
> + * a response back for most types of requests (except
> + * SMB Write past end of file which can be slow, and
> + * blocking lock operations). NFS waits slightly longer
> + * than CIFS, but this can make it take longer for
> + * nonresponsive servers to be detected and 15 seconds
> + * is more than enough time for modern networks to
> + * send a packet. In most cases if we fail to send
> + * after the retries we will kill the socket and
> + * reconnect which may clear the network problem.
> + */
> rc = kernel_sendmsg(ssocket, &smb_msg, &iov[first_vec],
> - n_vec - first_vec, total_len);
> - if ((rc == -ENOSPC) || (rc == -EAGAIN)) {
> + n_vec - first_vec, remaining);
> + if (rc == -ENOSPC || rc == -EAGAIN) {
> i++;
> - /*
> - * If blocking send we try 3 times, since each can block
> - * for 5 seconds. For nonblocking we have to try more
> - * but wait increasing amounts of time allowing time for
> - * socket to clear. The overall time we wait in either
> - * case to send on the socket is about 15 seconds.
> - * Similarly we wait for 15 seconds for a response from
> - * the server in SendReceive[2] for the server to send
> - * a response back for most types of requests (except
> - * SMB Write past end of file which can be slow, and
> - * blocking lock operations). NFS waits slightly longer
> - * than CIFS, but this can make it take longer for
> - * nonresponsive servers to be detected and 15 seconds
> - * is more than enough time for modern networks to
> - * send a packet. In most cases if we fail to send
> - * after the retries we will kill the socket and
> - * reconnect which may clear the network problem.
> - */
> - if ((i >= 14) || (!server->noblocksnd && (i > 2))) {
> - cERROR(1, "sends on sock %p stuck for 15 seconds",
> - ssocket);
> + if (i >= 14 || (!server->noblocksnd && (i > 2))) {
> + cERROR(1, "sends on sock %p stuck for 15 "
> + "seconds", ssocket);
> rc = -EAGAIN;
> break;
> }
> msleep(1 << i);
> continue;
> }
> +
> if (rc < 0)
> break;
>
> - if (rc == total_len) {
> - total_len = 0;
> + /* send was at least partially successful */
> + *sent += rc;
> +
> + if (rc == remaining) {
> + remaining = 0;
> break;
> - } else if (rc > total_len) {
> - cERROR(1, "sent %d requested %d", rc, total_len);
> + }
> +
> + if (rc > remaining) {
> + cERROR(1, "sent %d requested %d", rc, remaining);
> break;
> }
> +
> if (rc == 0) {
> /* should never happen, letting socket clear before
> retrying is our only obvious option here */
> @@ -201,7 +216,9 @@ smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
> msleep(500);
> continue;
> }
> - total_len -= rc;
> +
> + remaining -= rc;
> +
> /* the line below resets i */
> for (i = first_vec; i < n_vec; i++) {
> if (iov[i].iov_len) {
> @@ -216,16 +233,35 @@ smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
> }
> }
> }
> +
> i = 0; /* in case we get ENOSPC on the next send */
> + rc = 0;
> }
> + return rc;
> +}
> +
> +static int
> +smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst)
> +{
> + int rc;
> + struct kvec *iov = rqst->rq_iov;
> + int n_vec = rqst->rq_nvec;
> + unsigned int smb_buf_length = get_rfc1002_length(iov[0].iov_base);
> + size_t total_len;
> +
> + cFYI(1, "Sending smb: smb_len=%u", smb_buf_length);
> + dump_smb(iov[0].iov_base, iov[0].iov_len);
> +
> + rc = smb_send_kvec(server, iov, n_vec, &total_len);
>
> if ((total_len > 0) && (total_len != smb_buf_length + 4)) {
> - cFYI(1, "partial send (%d remaining), terminating session",
> - total_len);
> - /* If we have only sent part of an SMB then the next SMB
> - could be taken as the remainder of this one. We need
> - to kill the socket so the server throws away the partial
> - SMB */
> + cFYI(1, "partial send (wanted=%u sent=%zu): terminating "
> + "session", smb_buf_length + 4, total_len);
> + /*
> + * If we have only sent part of an SMB then the next SMB could
> + * be taken as the remainder of this one. We need to kill the
> + * socket so the server throws away the partial SMB
> + */
> server->tcpStatus = CifsNeedReconnect;
> }
>
> @@ -237,6 +273,15 @@ smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
> return rc;
> }
>
> +static int
> +smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
> +{
> + struct smb_rqst rqst = { .rq_iov = iov,
> + .rq_nvec = n_vec };
> +
> + return smb_send_rqst(server, &rqst);
> +}
> +
> int
> smb_send(struct TCP_Server_Info *server, struct smb_hdr *smb_buffer,
> unsigned int smb_buf_length)
> --
> 1.7.10.4
>
> --
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Looks good.
Reviewed-by: Pavel Shilovsky <pshilovsky@xxxxxxxxx>
--
Best regards,
Pavel Shilovsky.
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