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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Ronnie Sahlberg <lsahlber@redhat.com>,
        Steve French <stfrench@microsoft.com>
Subject: [PATCH 5.10 623/717] SMB3: avoid confusing warning message on mount to Azure
Date:   Mon, 28 Dec 2020 13:50:21 +0100
Message-Id: <20201228125050.774782951@linuxfoundation.org>
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From: Steve French <stfrench@microsoft.com>

commit ebcd6de98754d9b6a5f89d7835864b1c365d432f upstream.

Mounts to Azure cause an unneeded warning message in dmesg
   "CIFS: VFS: parse_server_interfaces: incomplete interface info"

Azure rounds up the size (by 8 additional bytes, to a
16 byte boundary) of the structure returned on the query
of the server interfaces at mount time.  This is permissible
even though different than other servers so do not log a warning
if query network interfaces response is only rounded up by 8
bytes or fewer.

CC: Stable <stable@vger.kernel.org>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/cifs/smb2ops.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -477,7 +477,8 @@ parse_server_interfaces(struct network_i
 		goto out;
 	}
 
-	if (bytes_left || p->Next)
+	/* Azure rounds the buffer size up 8, to a 16 byte boundary */
+	if ((bytes_left > 8) || p->Next)
 		cifs_dbg(VFS, "%s: incomplete interface info\n", __func__);