smb: Initialize cfid->tcon before performing network ops

Avoid leaking a tcon ref when a lease break races with opening the
cached directory. Processing the leak break might take a reference to
the tcon in cached_dir_lease_break() and then fail to release the ref in
cached_dir_offload_close, since cfid->tcon is still NULL.

Fixes: ebe98f1 ("cifs: enable caching of directories for which a lease is held")
Signed-off-by: Paul Aurich <paul@darkrain42.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: darkrain42

fs/smb/client/cached_dir.c

@@ -229,6 +229,7 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
 		}
 	}
 	cfid->dentry = dentry;
+	cfid->tcon = tcon;
 
 	/*
 	 * We do not hold the lock for the open because in case
@@ -300,7 +301,6 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
 		}
 		goto oshr_free;
 	}
-	cfid->tcon = tcon;
 	cfid->is_open = true;
 
 	spin_lock(&cfids->cfid_list_lock);