do not treat non-symlink reparse points as valid symlinks

Windows 8 and later can create NFS symlinks (within reparse points)
which we were assuming were normal NTFS symlinks and thus reporting
corrupt paths for.  Add check for reparse points to make sure that
they really are normal symlinks before we try to parse the pathname.

We also should not be parsing other types of reparse points (DFS
junctions etc) as if they were a  symlink so return EOPNOTSUPP
on those.  Also fix endian errors (we were not parsing symlink
lengths as little endian).

This fixes commit d244bf2dfbebfded05f494ffd53659fa7b1e32c1
which implemented follow link for non-Unix CIFS mounts

CC: Stable <stable@kernel.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/smbfsctl.h b/fs/cifs/smbfsctl.h
index d952ee4..a4b2391f 100644
--- a/fs/cifs/smbfsctl.h
+++ b/fs/cifs/smbfsctl.h
@@ -97,9 +97,23 @@
 #define FSCTL_QUERY_NETWORK_INTERFACE_INFO 0x001401FC /* BB add struct */
 #define FSCTL_SRV_READ_HASH          0x001441BB /* BB add struct */
 
+/* See FSCC 2.1.2.5 */
 #define IO_REPARSE_TAG_MOUNT_POINT   0xA0000003
 #define IO_REPARSE_TAG_HSM           0xC0000004
 #define IO_REPARSE_TAG_SIS           0x80000007
+#define IO_REPARSE_TAG_HSM2          0x80000006
+#define IO_REPARSE_TAG_DRIVER_EXTENDER 0x80000005
+/* Used by the DFS filter. See MS-DFSC */
+#define IO_REPARSE_TAG_DFS           0x8000000A
+/* Used by the DFS filter See MS-DFSC */
+#define IO_REPARSE_TAG_DFSR          0x80000012
+#define IO_REPARSE_TAG_FILTER_MANAGER 0x8000000B
+/* See section MS-FSCC 2.1.2.4 */
+#define IO_REPARSE_TAG_SYMLINK       0xA000000C
+#define IO_REPARSE_TAG_DEDUP         0x80000013
+#define IO_REPARSE_APPXSTREAM	     0xC0000014
+/* NFS symlinks, Win 8/SMB3 and later */
+#define IO_REPARSE_TAG_NFS           0x80000014
 
 /* fsctl flags */
 /* If Flags is set to this value, the request is an FSCTL not ioctl request */