Index: uspace/lib/block/libblock.c
===================================================================
--- uspace/lib/block/libblock.c	(revision 9c3164378bee71fae4eb09a7b395b970025b1a5e)
+++ uspace/lib/block/libblock.c	(revision 956d4df8bbb63353196c417c07c85c56831416c2)
@@ -626,4 +626,5 @@
 			unsigned long key = block->lba;
 			hash_table_remove(&cache->block_hash, &key, 1);
+			fibril_mutex_unlock(&block->lock);
 			free(block->data);
 			free(block);