Index: uspace/srv/fs/fat/fat_ops.c
===================================================================
--- uspace/srv/fs/fat/fat_ops.c	(revision 49647be8de2b9afcd1cd15911fb624a872d09ede)
+++ uspace/srv/fs/fat/fat_ops.c	(revision 1647323c457b17ec08ec245c295d83f7952313ff)
@@ -363,9 +363,14 @@
 				}
 				rc = fat_node_get_core(&nodep, idx);
-				assert(rc == EOK);
 				fibril_mutex_unlock(&idx->lock);
-				(void) block_put(b);
+				if (rc != EOK) {
+					(void) block_put(b);
+					return rc;
+				}
 				*rfn = FS_NODE(nodep);
-				return EOK;
+				rc = block_put(b);
+				if (rc != EOK)
+					(void) fat_node_put(*rfn);
+				return rc;
 			}
 		}