From c1508ca23653245266e2e3ab69a8dad464f7a569 Mon Sep 17 00:00:00 2001
From: Sean Finney <seanius@seanius.net>
Date: Mon, 11 Apr 2011 13:19:31 +0000
Subject: [PATCH] cifs: Add support for mounting Windows 2008 DFS shares
Windows 2008 CIFS servers do not always return PATH_NOT_COVERED when
attempting to access a DFS share. Therefore, when checking for remote
shares, unconditionally ask for a DFS referral for the UNC (w/out prepath)
before continuing with previous behavior of attempting to access the UNC +
prepath and checking for PATH_NOT_COVERED.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=31092
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Sean Finney <seanius@seanius.net>
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>
---
fs/cifs/connect.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index b6c6a3629b07..c7ebeee38c67 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2937,6 +2937,24 @@ try_mount_again:
(tcon->ses->server->maxBuf - MAX_CIFS_HDR_SIZE));
remote_path_check:
+#ifdef CONFIG_CIFS_DFS_UPCALL
+ /*
+ * Perform an unconditional check for whether there are DFS
+ * referrals for this path without prefix, to provide support
+ * for DFS referrals from w2k8 servers which don't seem to respond
+ * with PATH_NOT_COVERED to requests that include the prefix.
+ * Chase the referral if found, otherwise continue normally.
+ */
+ if (referral_walks_count == 0) {
+ int refrc = expand_dfs_referral(xid, pSesInfo, volume_info,
+ cifs_sb, &mount_data, false);
+ if (!refrc) {
+ referral_walks_count++;
+ goto try_mount_again;
+ }
+ }
+#endif
+
/* check if a whole path (including prepath) is not remote */
if (!rc && tcon) {
/* build_path_to_root works only when we have a valid tcon */
--
2.20.1