Index: uspace/lib/block/libblock.c
===================================================================
--- uspace/lib/block/libblock.c	(revision e2729490c49a14c12cbf5fc99e4232c52c784203)
+++ uspace/lib/block/libblock.c	(revision f483a1595e01c6dce011869a0e03969833df9750)
@@ -627,4 +627,5 @@
 			unsigned long key = block->lba;
 			hash_table_remove(&cache->block_hash, &key, 1);
+			fibril_mutex_unlock(&block->lock);
 			free(block->data);
 			free(block);