Index: uspace/lib/libblock/libblock.c
===================================================================
--- uspace/lib/libblock/libblock.c	(revision 02ee6bf5ae5ca9f0d3dacdc857c376ed7f970a4b)
+++ uspace/lib/libblock/libblock.c	(revision c91f2d1b74337f64f6bb816a3391eb3b801b5031)
@@ -313,4 +313,6 @@
 /** Instantiate a block in memory and get a reference to it.
  *
+ * @param block			Pointer to where the function will store the
+ * 				block pointer on success.
  * @param dev_handle		Device handle of the block device.
  * @param boff			Block offset.
@@ -319,7 +321,7 @@
  *				device.
  *
- * @return			Block structure.
- */
-block_t *block_get(dev_handle_t dev_handle, bn_t boff, int flags)
+ * @return			EOK on success or a negative error code.
+ */
+int block_get(block_t **block, dev_handle_t dev_handle, bn_t boff, int flags)
 {
 	devcon_t *devcon;
@@ -450,5 +452,6 @@
 		fibril_mutex_unlock(&b->lock);
 	}
-	return b;
+	*block = b;
+	return EOK;
 }
 
@@ -458,6 +461,8 @@
  *
  * @param block		Block of which a reference is to be released.
- */
-void block_put(block_t *block)
+ *
+ * @return		EOK on success or a negative error code.
+ */
+int block_put(block_t *block)
 {
 	devcon_t *devcon = devcon_search(block->dev_handle);
@@ -546,4 +551,6 @@
 	fibril_mutex_unlock(&block->lock);
 	fibril_mutex_unlock(&cache->lock);
+
+	return EOK;
 }
 
Index: uspace/lib/libblock/libblock.h
===================================================================
--- uspace/lib/libblock/libblock.h	(revision 02ee6bf5ae5ca9f0d3dacdc857c376ed7f970a4b)
+++ uspace/lib/libblock/libblock.h	(revision c91f2d1b74337f64f6bb816a3391eb3b801b5031)
@@ -101,6 +101,6 @@
 extern int block_cache_init(dev_handle_t, size_t, unsigned, enum cache_mode);
 
-extern block_t *block_get(dev_handle_t, bn_t, int);
-extern void block_put(block_t *);
+extern int block_get(block_t **, dev_handle_t, bn_t, int);
+extern int block_put(block_t *);
 
 extern int block_seqread(dev_handle_t, off_t *, size_t *, off_t *, void *,