xprtrdma: Properly handle RDMA_ERROR replies

These are shorter than RPCRDMA_HDRLEN_MIN, and they need to
complete the waiting RPC.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

2 files changed, 49 insertions, 13 deletions

diff --git a/include/linux/sunrpc/rpc_rdma.h b/include/linux/sunrpc/rpc_rdma.h
index 8c6d23cb0cae..3b1ff38f0c37 100644
--- a/include/linux/sunrpc/rpc_rdma.h
+++ b/include/linux/sunrpc/rpc_rdma.h
@@ -93,6 +93,12 @@ struct rpcrdma_msg {
                         __be32 rm_pempty[3];    /* 3 empty chunk lists */
                 } rm_padded;
 
+                struct {
+                        __be32 rm_err;
+                        __be32 rm_vers_low;
+                        __be32 rm_vers_high;
+                } rm_error;
+
                 __be32 rm_chunks[0];    /* read, write and reply chunks */
 
         } rm_body;
@@ -109,11 +115,6 @@ enum rpcrdma_errcode {
         ERR_CHUNK = 2
 };
 
-struct rpcrdma_err_vers {
-        uint32_t rdma_vers_low; /* Version range supported by peer */
-        uint32_t rdma_vers_high;
-};
-
 enum rpcrdma_proc {
         RDMA_MSG = 0,           /* An RPC call or reply msg */
         RDMA_NOMSG = 1,         /* An RPC call or reply msg - separate body */
diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index 060739144552..35f810899729 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -795,7 +795,7 @@ rpcrdma_reply_handler(struct rpcrdma_rep *rep)
         struct rpcrdma_xprt *r_xprt = rep->rr_rxprt;
         struct rpc_xprt *xprt = &r_xprt->rx_xprt;
         __be32 *iptr;
-        int rdmalen, status;
+        int rdmalen, status, rmerr;
         unsigned long cwnd;
         u32 credits;
 
@@ -803,12 +803,10 @@ rpcrdma_reply_handler(struct rpcrdma_rep *rep)
 
         if (rep->rr_len == RPCRDMA_BAD_LEN)
                 goto out_badstatus;
-        if (rep->rr_len < RPCRDMA_HDRLEN_MIN)
+        if (rep->rr_len < RPCRDMA_HDRLEN_ERR)
                 goto out_shortreply;
 
         headerp = rdmab_to_msg(rep->rr_rdmabuf);
-        if (headerp->rm_vers != rpcrdma_version)
-                goto out_badversion;
 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
         if (rpcrdma_is_bcall(headerp))
                 goto out_bcall;
@@ -838,6 +836,9 @@ rpcrdma_reply_handler(struct rpcrdma_rep *rep)
         req->rl_reply = rep;
         xprt->reestablish_timeout = 0;
 
+        if (headerp->rm_vers != rpcrdma_version)
+                goto out_badversion;
+
         /* check for expected message types */
         /* The order of some of these tests is important. */
         switch (headerp->rm_type) {
@@ -898,6 +899,9 @@ rpcrdma_reply_handler(struct rpcrdma_rep *rep)
                 status = rdmalen;
                 break;
 
+        case rdma_error:
+                goto out_rdmaerr;
+
 badheader:
         default:
                 dprintk("%s: invalid rpcrdma reply header (type %d):"
@@ -913,6 +917,7 @@ badheader:
                 break;
         }
 
+out:
         /* Invalidate and flush the data payloads before waking the
          * waiting application. This guarantees the memory region is
          * properly fenced from the server before the application
@@ -955,13 +960,43 @@ out_bcall:
         return;
 #endif
 
-out_shortreply:
-        dprintk("RPC:       %s: short/invalid reply\n", __func__);
-        goto repost;
-
+/* If the incoming reply terminated a pending RPC, the next
+ * RPC call will post a replacement receive buffer as it is
+ * being marshaled.
+ */
 out_badversion:
         dprintk("RPC:       %s: invalid version %d\n",
                 __func__, be32_to_cpu(headerp->rm_vers));
+        status = -EIO;
+        r_xprt->rx_stats.bad_reply_count++;
+        goto out;
+
+out_rdmaerr:
+        rmerr = be32_to_cpu(headerp->rm_body.rm_error.rm_err);
+        switch (rmerr) {
+        case ERR_VERS:
+                pr_err("%s: server reports header version error (%u-%u)\n",
+                       __func__,
+                       be32_to_cpu(headerp->rm_body.rm_error.rm_vers_low),
+                       be32_to_cpu(headerp->rm_body.rm_error.rm_vers_high));
+                break;
+        case ERR_CHUNK:
+                pr_err("%s: server reports header decoding error\n",
+                       __func__);
+                break;
+        default:
+                pr_err("%s: server reports unknown error %d\n",
+                       __func__, rmerr);
+        }
+        status = -EREMOTEIO;
+        r_xprt->rx_stats.bad_reply_count++;
+        goto out;
+
+/* If no pending RPC transaction was matched, post a replacement
+ * receive buffer before returning.
+ */
+out_shortreply:
+        dprintk("RPC:       %s: short/invalid reply\n", __func__);
         goto repost;
 
 out_nomatch: