nfsd41: sunrpc: Added rpc server-side backchannel handling

When the call direction is a reply, copy the xid and call direction into the
req->rq_private_buf.head[0].iov_base otherwise rpc_verify_header returns
rpc_garbage.

Signed-off-by: Rahul Iyer <iyer@netapp.com>
Signed-off-by: Mike Sager <sager@netapp.com>
Signed-off-by: Marc Eshel <eshel@almaden.ibm.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[get rid of CONFIG_NFSD_V4_1]
[sunrpc: refactoring of svc_tcp_recvfrom]
[nfsd41: sunrpc: create common send routine for the fore and the back channels]
[nfsd41: sunrpc: Use free_page() to free server backchannel pages]
[nfsd41: sunrpc: Document server backchannel locking]
[nfsd41: sunrpc: remove bc_connect_worker()]
[nfsd41: sunrpc: Define xprt_server_backchannel()[
[nfsd41: sunrpc: remove bc_close and bc_init_auto_disconnect dummy functions]
[nfsd41: sunrpc: eliminate unneeded switch statement in xs_setup_tcp()]
[nfsd41: sunrpc: Don't auto close the server backchannel connection]
[nfsd41: sunrpc: Remove unused functions]
Signed-off-by: Alexandros Batsakis <batsakis@netapp.com>
Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[nfsd41: change bc_sock to bc_xprt]
[nfsd41: sunrpc: move struct rpc_buffer def into a common header file]
[nfsd41: sunrpc: use rpc_sleep in bc_send_request so not to block on mutex]
[removed cosmetic changes]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[sunrpc: add new xprt class for nfsv4.1 backchannel]
[sunrpc: v2.1 change handling of auto_close and init_auto_disconnect operations for the nfsv4.1 backchannel]
Signed-off-by: Alexandros Batsakis <batsakis@netapp.com>
[reverted more cosmetic leftovers]
[got rid of xprt_server_backchannel]
[separated "nfsd41: sunrpc: add new xprt class for nfsv4.1 backchannel"]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Cc: Trond Myklebust <trond.myklebust@netapp.com>
[sunrpc: change idle timeout value for the backchannel]
Signed-off-by: Alexandros Batsakis <batsakis@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Acked-by: Trond Myklebust <trond.myklebust@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

1 files changed, 137 insertions, 35 deletions

diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 76a380d37de4..ccc5e83cae5d 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -49,6 +49,7 @@
 #include <linux/sunrpc/msg_prot.h>
 #include <linux/sunrpc/svcsock.h>
 #include <linux/sunrpc/stats.h>
+#include <linux/sunrpc/xprt.h>
 
 #define RPCDBG_FACILITY RPCDBG_SVCXPRT
 
@@ -153,49 +154,27 @@ static void svc_set_cmsg_data(struct svc_rqst *rqstp, struct cmsghdr *cmh)
 }
 
 /*
- * Generic sendto routine
+ * send routine intended to be shared by the fore- and back-channel
  */
-static int svc_sendto(struct svc_rqst *rqstp, struct xdr_buf *xdr)
+int svc_send_common(struct socket *sock, struct xdr_buf *xdr,
+                    struct page *headpage, unsigned long headoffset,
+                    struct page *tailpage, unsigned long tailoffset)
 {
-        struct svc_sock *svsk =
-                container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
-        struct socket   *sock = svsk->sk_sock;
-        int             slen;
-        union {
-                struct cmsghdr  hdr;
-                long            all[SVC_PKTINFO_SPACE / sizeof(long)];
-        } buffer;
-        struct cmsghdr *cmh = &buffer.hdr;
-        int             len = 0;
         int             result;
         int             size;
         struct page     **ppage = xdr->pages;
         size_t          base = xdr->page_base;
         unsigned int    pglen = xdr->page_len;
         unsigned int    flags = MSG_MORE;
-        RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
+        int             slen;
+        int             len = 0;
 
         slen = xdr->len;
 
-        if (rqstp->rq_prot == IPPROTO_UDP) {
-                struct msghdr msg = {
-                        .msg_name       = &rqstp->rq_addr,
-                        .msg_namelen    = rqstp->rq_addrlen,
-                        .msg_control    = cmh,
-                        .msg_controllen = sizeof(buffer),
-                        .msg_flags      = MSG_MORE,
-                };
-
-                svc_set_cmsg_data(rqstp, cmh);
-
-                if (sock_sendmsg(sock, &msg, 0) < 0)
-                        goto out;
-        }
-
         /* send head */
         if (slen == xdr->head[0].iov_len)
                 flags = 0;
-        len = kernel_sendpage(sock, rqstp->rq_respages[0], 0,
+        len = kernel_sendpage(sock, headpage, headoffset,
                                   xdr->head[0].iov_len, flags);
         if (len != xdr->head[0].iov_len)
                 goto out;
@@ -219,16 +198,58 @@ static int svc_sendto(struct svc_rqst *rqstp, struct xdr_buf *xdr)
                 base = 0;
                 ppage++;
         }
+
         /* send tail */
         if (xdr->tail[0].iov_len) {
-                result = kernel_sendpage(sock, rqstp->rq_respages[0],
-                                             ((unsigned long)xdr->tail[0].iov_base)
-                                                & (PAGE_SIZE-1),
-                                             xdr->tail[0].iov_len, 0);
-
+                result = kernel_sendpage(sock, tailpage, tailoffset,
+                                   xdr->tail[0].iov_len, 0);
                 if (result > 0)
                         len += result;
         }
+
+out:
+        return len;
+}
+
+
+/*
+ * Generic sendto routine
+ */
+static int svc_sendto(struct svc_rqst *rqstp, struct xdr_buf *xdr)
+{
+        struct svc_sock *svsk =
+                container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
+        struct socket   *sock = svsk->sk_sock;
+        union {
+                struct cmsghdr  hdr;
+                long            all[SVC_PKTINFO_SPACE / sizeof(long)];
+        } buffer;
+        struct cmsghdr *cmh = &buffer.hdr;
+        int             len = 0;
+        unsigned long tailoff;
+        unsigned long headoff;
+        RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
+
+        if (rqstp->rq_prot == IPPROTO_UDP) {
+                struct msghdr msg = {
+                        .msg_name       = &rqstp->rq_addr,
+                        .msg_namelen    = rqstp->rq_addrlen,
+                        .msg_control    = cmh,
+                        .msg_controllen = sizeof(buffer),
+                        .msg_flags      = MSG_MORE,
+                };
+
+                svc_set_cmsg_data(rqstp, cmh);
+
+                if (sock_sendmsg(sock, &msg, 0) < 0)
+                        goto out;
+        }
+
+        tailoff = ((unsigned long)xdr->tail[0].iov_base) & (PAGE_SIZE-1);
+        headoff = 0;
+        len = svc_send_common(sock, xdr, rqstp->rq_respages[0], headoff,
+                               rqstp->rq_respages[0], tailoff);
+
 out:
         dprintk("svc: socket %p sendto([%p %Zu... ], %d) = %d (addr %s)\n",
                 svsk, xdr->head[0].iov_base, xdr->head[0].iov_len,
@@ -951,6 +972,57 @@ static int svc_tcp_recv_record(struct svc_sock *svsk, struct svc_rqst *rqstp)
         return -EAGAIN;
 }
 
+static int svc_process_calldir(struct svc_sock *svsk, struct svc_rqst *rqstp,
+                               struct rpc_rqst **reqpp, struct kvec *vec)
+{
+        struct rpc_rqst *req = NULL;
+        u32 *p;
+        u32 xid;
+        u32 calldir;
+        int len;
+
+        len = svc_recvfrom(rqstp, vec, 1, 8);
+        if (len < 0)
+                goto error;
+
+        p = (u32 *)rqstp->rq_arg.head[0].iov_base;
+        xid = *p++;
+        calldir = *p;
+
+        if (calldir == 0) {
+                /* REQUEST is the most common case */
+                vec[0] = rqstp->rq_arg.head[0];
+        } else {
+                /* REPLY */
+                if (svsk->sk_bc_xprt)
+                        req = xprt_lookup_rqst(svsk->sk_bc_xprt, xid);
+
+                if (!req) {
+                        printk(KERN_NOTICE
+                                "%s: Got unrecognized reply: "
+                                "calldir 0x%x sk_bc_xprt %p xid %08x\n",
+                                __func__, ntohl(calldir),
+                                svsk->sk_bc_xprt, xid);
+                        vec[0] = rqstp->rq_arg.head[0];
+                        goto out;
+                }
+
+                memcpy(&req->rq_private_buf, &req->rq_rcv_buf,
+                       sizeof(struct xdr_buf));
+                /* copy the xid and call direction */
+                memcpy(req->rq_private_buf.head[0].iov_base,
+                       rqstp->rq_arg.head[0].iov_base, 8);
+                vec[0] = req->rq_private_buf.head[0];
+        }
+ out:
+        vec[0].iov_base += 8;
+        vec[0].iov_len -= 8;
+        len = svsk->sk_reclen - 8;
+ error:
+        *reqpp = req;
+        return len;
+}
+
 /*
  * Receive data from a TCP socket.
  */
@@ -962,6 +1034,7 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
         int             len;
         struct kvec *vec;
         int pnum, vlen;
+        struct rpc_rqst *req = NULL;
 
         dprintk("svc: tcp_recv %p data %d conn %d close %d\n",
                 svsk, test_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags),
@@ -975,9 +1048,27 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
         vec = rqstp->rq_vec;
         vec[0] = rqstp->rq_arg.head[0];
         vlen = PAGE_SIZE;
+
+        /*
+         * We have enough data for the whole tcp record. Let's try and read the
+         * first 8 bytes to get the xid and the call direction. We can use this
+         * to figure out if this is a call or a reply to a callback. If
+         * sk_reclen is < 8 (xid and calldir), then this is a malformed packet.
+         * In that case, don't bother with the calldir and just read the data.
+         * It will be rejected in svc_process.
+         */
+        if (len >= 8) {
+                len = svc_process_calldir(svsk, rqstp, &req, vec);
+                if (len < 0)
+                        goto err_again;
+                vlen -= 8;
+        }
+
         pnum = 1;
         while (vlen < len) {
-                vec[pnum].iov_base = page_address(rqstp->rq_pages[pnum]);
+                vec[pnum].iov_base = (req) ?
+                        page_address(req->rq_private_buf.pages[pnum - 1]) :
+                        page_address(rqstp->rq_pages[pnum]);
                 vec[pnum].iov_len = PAGE_SIZE;
                 pnum++;
                 vlen += PAGE_SIZE;
@@ -989,6 +1080,16 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
         if (len < 0)
                 goto err_again;
 
+        /*
+         * Account for the 8 bytes we read earlier
+         */
+        len += 8;
+
+        if (req) {
+                xprt_complete_rqst(req->rq_task, len);
+                len = 0;
+                goto out;
+        }
         dprintk("svc: TCP complete record (%d bytes)\n", len);
         rqstp->rq_arg.len = len;
         rqstp->rq_arg.page_base = 0;
@@ -1002,6 +1103,7 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
         rqstp->rq_xprt_ctxt   = NULL;
         rqstp->rq_prot        = IPPROTO_TCP;
 
+out:
         /* Reset TCP read info */
         svsk->sk_reclen = 0;
         svsk->sk_tcplen = 0;