cifs: use DFS root session instead of tcon ses

commit 6284e46bdd47743a064fe6ac834a7ac05b1fd206 upstream.

Use DFS root session whenever possible to get new DFS referrals
otherwise we might end up with an IPC tcon (tcon->ses->tcon_ipc) that
doesn't respond to them.  It should be safe accessing
@ses->dfs_root_ses directly in cifs_inval_name_dfs_link_error() as it
has same lifetime as of @tcon.

Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Cc: stable@vger.kernel.org # 6.2
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index 855cc523de25e28b898b9e0993b94128b4e06df8..9f4486b705d5c6cea4959a8c55cc1a1d955e182f 100644 (file)
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -1364,6 +1364,7 @@ int cifs_inval_name_dfs_link_error(const unsigned int xid,
                 * removing cached DFS targets that the client would eventually
                 * need during failover.
                 */
+               ses = CIFS_DFS_ROOT_SES(ses);
                if (ses->server->ops->get_dfs_refer &&
                    !ses->server->ops->get_dfs_refer(xid, ses, ref_path, &refs,
                                                     &num_refs, cifs_sb->local_nls,