---

yaml
---
r: 264277
b: refs/heads/master
c: 983c7db
h: refs/heads/master
i:
  264275: ed2075e
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 8232480944d173378082ebb2cac8a3207c08cf31
+refs/heads/master: 983c7db347db8ce2d8453fd1d89b7a4bb6920d56

trunk/drivers/md/dm-crypt.c

@@ -1698,6 +1698,8 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	}
 
 	ti->num_flush_requests = 1;
+	ti->discard_zeroes_data_unsupported = 1;
+
 	return 0;
 
 bad:

trunk/drivers/md/dm-table.c

@@ -1283,6 +1283,22 @@ static bool dm_table_supports_flush(struct dm_table *t, unsigned flush)
 	return 0;
 }
 
+static bool dm_table_discard_zeroes_data(struct dm_table *t)
+{
+	struct dm_target *ti;
+	unsigned i = 0;
+
+	/* Ensure that all targets supports discard_zeroes_data. */
+	while (i < dm_table_get_num_targets(t)) {
+		ti = dm_table_get_target(t, i++);
+
+		if (ti->discard_zeroes_data_unsupported)
+			return 0;
+	}
+
+	return 1;
+}
+
 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
 			       struct queue_limits *limits)
 {
@@ -1305,6 +1321,9 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
 	}
 	blk_queue_flush(q, flush);
 
+	if (!dm_table_discard_zeroes_data(t))
+		q->limits.discard_zeroes_data = 0;
+
 	dm_table_set_integrity(t);
 
 	/*

trunk/include/linux/device-mapper.h

@@ -197,6 +197,11 @@ struct dm_target {
 	 * whether or not its underlying devices have support.
 	 */
 	unsigned discards_supported:1;
+
+	/*
+	 * Set if this target does not return zeroes on discarded blocks.
+	 */
+	unsigned discard_zeroes_data_unsupported:1;
 };
 
 /* Each target can link one of these into the table */