[PATCH 3.12 13/58] CIFS: Fix SMB2+ interim response processing for read requests

[Jiri Slaby]

From: Pavel Shilovsky <pshilov...@samba.org>

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

===============

commit 6cc3b24235929b54acd5ecc987ef11a425bd209e upstream.

For interim responses we only need to parse a header and update
a number credits. Now it is done for all SMB2+ command except
SMB2_READ which is wrong. Fix this by adding such processing.

Signed-off-by: Pavel Shilovsky <pshilov...@samba.org>
Tested-by: Shirish Pargaonkar <shirishpargaon...@gmail.com>
Signed-off-by: Steve French <smfre...@gmail.com>
Signed-off-by: Jiri Slaby <jsl...@suse.cz>
---
 fs/cifs/cifssmb.c | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index ea938a8bf240..f53a6e8204d8 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -1378,11 +1378,10 @@ openRetry:
  * current bigbuf.
  */
 static int
-cifs_readv_discard(struct TCP_Server_Info *server, struct mid_q_entry *mid)
+discard_remaining_data(struct TCP_Server_Info *server)
 {
        unsigned int rfclen = get_rfc1002_length(server->smallbuf);
        int remaining = rfclen + 4 - server->total_read;
-       struct cifs_readdata *rdata = mid->callback_data;
 
        while (remaining > 0) {
                int length;
@@ -1396,10 +1395,20 @@ cifs_readv_discard(struct TCP_Server_Info *server, 
struct mid_q_entry *mid)
                remaining -= length;
        }
 
-       dequeue_mid(mid, rdata->result);
        return 0;
 }
 
+static int
+cifs_readv_discard(struct TCP_Server_Info *server, struct mid_q_entry *mid)
+{
+       int length;
+       struct cifs_readdata *rdata = mid->callback_data;
+
+       length = discard_remaining_data(server);
+       dequeue_mid(mid, rdata->result);
+       return length;
+}
+
 int
 cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 {
@@ -1428,6 +1437,12 @@ cifs_readv_receive(struct TCP_Server_Info *server, 
struct mid_q_entry *mid)
                return length;
        server->total_read += length;
 
+       if (server->ops->is_status_pending &&
+           server->ops->is_status_pending(buf, server, 0)) {
+               discard_remaining_data(server);
+               return -1;
+       }
+
        /* Was the SMB read successful? */
        rdata->result = server->ops->map_error(buf, false);
        if (rdata->result != 0) {
-- 
2.7.3