[v5,2/6] cifs: Add support for mounting Windows 2008 DFS shares

Commit Message

Sean Finney April 11, 2011, 1:19 p.m. UTC

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 <[e-mail]>
Signed-off-by: Sean Finney <[e-mail]>
---
 fs/cifs/connect.c |   18 ++++++++++++++++++
 1 files changed, 18 insertions(+), 0 deletions(-)

Patch

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index c89d871..4873bac 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2934,6 +2934,24 @@  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 */