CIFS: Fix credits calculations for reads with errors

Currently we mark MID as malformed if we get an error from server
in a read response. This leads to not properly processing credits
in the readv callback. Fix this by marking such a response as
normal received response and process it appropriately.

Cc: <stable@vger.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index e18915415e1337dc22e5fca260e9011ac5b1a37e..bb54ccf8481c33937d3dfa6b0a782971112a74fc 100644 (file)
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -1549,18 +1549,26 @@ cifs_discard_remaining_data(struct TCP_Server_Info *server)
 }
 
 static int
-cifs_readv_discard(struct TCP_Server_Info *server, struct mid_q_entry *mid)
+__cifs_readv_discard(struct TCP_Server_Info *server, struct mid_q_entry *mid,
+                    bool malformed)
 {
        int length;
-       struct cifs_readdata *rdata = mid->callback_data;
 
        length = cifs_discard_remaining_data(server);
-       dequeue_mid(mid, rdata->result);
+       dequeue_mid(mid, malformed);
        mid->resp_buf = server->smallbuf;
        server->smallbuf = NULL;
        return length;
 }
 
+static int
+cifs_readv_discard(struct TCP_Server_Info *server, struct mid_q_entry *mid)
+{
+       struct cifs_readdata *rdata = mid->callback_data;
+
+       return  __cifs_readv_discard(server, mid, rdata->result);
+}
+
 int
 cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 {
@@ -1602,12 +1610,23 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
                return -1;
        }
 
+       /* set up first two iov for signature check and to get credits */
+       rdata->iov[0].iov_base = buf;
+       rdata->iov[0].iov_len = 4;
+       rdata->iov[1].iov_base = buf + 4;
+       rdata->iov[1].iov_len = server->total_read - 4;
+       cifs_dbg(FYI, "0: iov_base=%p iov_len=%zu\n",
+                rdata->iov[0].iov_base, rdata->iov[0].iov_len);
+       cifs_dbg(FYI, "1: iov_base=%p iov_len=%zu\n",
+                rdata->iov[1].iov_base, rdata->iov[1].iov_len);
+
        /* Was the SMB read successful? */
        rdata->result = server->ops->map_error(buf, false);
        if (rdata->result != 0) {
                cifs_dbg(FYI, "%s: server returned error %d\n",
                         __func__, rdata->result);
-               return cifs_readv_discard(server, mid);
+               /* normal error on read response */
+               return __cifs_readv_discard(server, mid, false);
        }
 
        /* Is there enough to get to the rest of the READ_RSP header? */
@@ -1651,14 +1670,6 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
                server->total_read += length;
        }
 
-       /* set up first iov for signature check */
-       rdata->iov[0].iov_base = buf;
-       rdata->iov[0].iov_len = 4;
-       rdata->iov[1].iov_base = buf + 4;
-       rdata->iov[1].iov_len = server->total_read - 4;
-       cifs_dbg(FYI, "0: iov_base=%p iov_len=%u\n",
-                rdata->iov[0].iov_base, server->total_read);
-
        /* how much data is in the response? */
 #ifdef CONFIG_CIFS_SMB_DIRECT
        use_rdma_mr = rdata->mr;