cifs: use CreationTime like an i_generation field

Reduce false inode collisions by using the CreationTime like an
i_generation field. This way, even if the server ends up reusing
a uniqueid after a delete/create cycle, we can avoid matching
the inode incorrectly.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index e6590e6..606ca8b 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -453,6 +453,7 @@
 	bool invalid_mapping:1;		/* pagecache is invalid */
 	u64  server_eof;		/* current file size on server */
 	u64  uniqueid;			/* server inode number */
+	u64  createtime;		/* creation time on server */
 #ifdef CONFIG_CIFS_FSCACHE
 	struct fscache_cookie *fscache;
 #endif
@@ -573,6 +574,7 @@
 	u64		cf_uniqueid;
 	u64		cf_eof;
 	u64		cf_bytes;
+	u64		cf_createtime;
 	uid_t		cf_uid;
 	gid_t		cf_gid;
 	umode_t		cf_mode;