CIFS: Use multicredits for SMB 2.1/3 writes

If we negotiate SMB 2.1 and higher version of the protocol and
a server supports large write buffer size, we need to consume 1
credit per 65536 bytes. So, we need to know how many credits
we have and obtain the required number of them before constructing
a writedata structure in writepages and iovec write.

Reviewed-by: Shirish Pargaonkar <spargaonkar@suse.com>
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/fs/cifs/smb2transport.c b/fs/cifs/smb2transport.c
index 59c748ce872f..5111e7272db6 100644
--- a/fs/cifs/smb2transport.c
+++ b/fs/cifs/smb2transport.c
@@ -466,7 +466,12 @@ smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 static inline void
 smb2_seq_num_into_buf(struct TCP_Server_Info *server, struct smb2_hdr *hdr)
 {
+        unsigned int i, num = le16_to_cpu(hdr->CreditCharge);
+
         hdr->MessageId = get_next_mid64(server);
+        /* skip message numbers according to CreditCharge field */
+        for (i = 1; i < num; i++)
+                get_next_mid(server);
 }
 
 static struct mid_q_entry *