Index: uspace/srv/fs/fat/fat_idx.c
===================================================================
--- uspace/srv/fs/fat/fat_idx.c	(revision 6ebe72166e34f2b3734f6630c9ca7d45806c9826)
+++ uspace/srv/fs/fat/fat_idx.c	(revision ca093b3073e434d8d83f2624b993aa1f3905e741)
@@ -464,5 +464,5 @@
 	if (l) {
 		fidx = hash_table_get_instance(l, fat_idx_t, uih_link);
-		futex_down(&fidx->lock);
+		fibril_mutex_lock(&fidx->lock);
 	}
 	fibril_mutex_unlock(&used_lock);