Index: uspace/lib/block/libblock.c
===================================================================
--- uspace/lib/block/libblock.c	(revision 0f1cf7a31b3863c9e813511f9a942482d21348fd)
+++ uspace/lib/block/libblock.c	(revision a99330e895a4dda435b60de880a00bc40762016a)
@@ -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);