cifs: add lease tracking to the cached root fid

Use a read lease for the cached root fid so that we can detect
when the content of the directory changes (via a break) at which time
we close the handle. On next access to the root the handle will be reopened
and cached again.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index af29ade1..bb40f3c 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -117,8 +117,9 @@ tconInfoAlloc(void)
 		INIT_LIST_HEAD(&ret_buf->openFileList);
 		INIT_LIST_HEAD(&ret_buf->tcon_list);
 		spin_lock_init(&ret_buf->open_file_lock);
-		mutex_init(&ret_buf->prfid_mutex);
-		ret_buf->prfid = kzalloc(sizeof(struct cifs_fid), GFP_KERNEL);
+		mutex_init(&ret_buf->crfid.fid_mutex);
+		ret_buf->crfid.fid = kzalloc(sizeof(struct cifs_fid),
+					     GFP_KERNEL);
 #ifdef CONFIG_CIFS_STATS
 		spin_lock_init(&ret_buf->stat_lock);
 #endif
@@ -136,7 +137,7 @@ tconInfoFree(struct cifs_tcon *buf_to_free)
 	atomic_dec(&tconInfoAllocCount);
 	kfree(buf_to_free->nativeFileSystem);
 	kzfree(buf_to_free->password);
-	kfree(buf_to_free->prfid);
+	kfree(buf_to_free->crfid.fid);
 	kfree(buf_to_free);
 }