From: Steve French <stfrench@microsoft.com>
Date: Thu, 14 Feb 2019 01:19:02 -0600
Subject: [PATCH] smb3: request more credits on tree connect
Git-commit: 4fe75c4e4bc2caeb4159573e26cf3075e2c0fd9b
Patch-mainline: v5.1-rc1
References: bsc#1144333

If we try large I/O (read or write) immediately after mount
we won't typically have enough credits because we only request
large amounts of credits on the first session setup.  So if
large I/O is attempted soon after mount we will typically only
have about 43 credits rather than 105 credits (with this patch)
available for the large i/o (which needs 64 credits minimum).

This patch requests more credits during tree connect, which
helps ensure that we have enough credits when mount completes
(between these requests and the first session setup) in order
 to start large I/O immediately after mount if needed.

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Acked-by: Aurelien Aptel <aaptel@suse.com>
---
 fs/cifs/smb2pdu.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 7d9a1cb9ecae..3e9bee35a03c 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -1614,6 +1614,9 @@ SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
 	rqst.rq_iov = iov;
 	rqst.rq_nvec = 2;
 
+	/* Need 64 for max size write so ask for more in case not there yet */
+	req->sync_hdr.CreditRequest = cpu_to_le16(64);
+
 	rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
 	cifs_small_buf_release(req);
 	rsp = (struct smb2_tree_connect_rsp *)rsp_iov.iov_base;
-- 
2.16.4