[PATCH 4.14 32/68] CIFS: Fix credit calculation for encrypted reads with errors

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>

commit ec678eae746dd25766a61c4095e2b649d3b20b09 upstream.

We do need to account for credits received in error responses
to read requests on encrypted sessions.

Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>
Reviewed-by: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/cifs/smb2ops.c |   24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -2531,11 +2531,23 @@ handle_read_data(struct TCP_Server_Info
 			server->ops->is_status_pending(buf, server, 0))
 		return -1;
 
-	rdata->result = server->ops->map_error(buf, false);
+	/* set up first two iov 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 =
+		min_t(unsigned int, buf_len, server->vals->read_rsp_size) - 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);
+
+	rdata->result = server->ops->map_error(buf, true);
 	if (rdata->result != 0) {
 		cifs_dbg(FYI, "%s: server returned error %d\n",
 			 __func__, rdata->result);
-		dequeue_mid(mid, rdata->result);
+		/* normal error on read response */
+		dequeue_mid(mid, false);
 		return 0;
 	}
 
@@ -2605,14 +2617,6 @@ handle_read_data(struct TCP_Server_Info
 		return 0;
 	}
 
-	/* 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->vals->read_rsp_size - 4;
-	cifs_dbg(FYI, "0: iov_base=%p iov_len=%zu\n",
-		 rdata->iov[0].iov_base, server->vals->read_rsp_size);
-
 	length = rdata->copy_into_pages(server, rdata, &iter);
 
 	kfree(bvec);