block: Add sysfs entry for fua support

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-sysfs.c

@@ -491,6 +491,11 @@ static ssize_t queue_wc_store(struct request_queue *q, const char *page,
 	return count;
 }
 
+static ssize_t queue_fua_show(struct request_queue *q, char *page)
+{
+	return sprintf(page, "%u\n", test_bit(QUEUE_FLAG_FUA, &q->queue_flags));
+}
+
 static ssize_t queue_dax_show(struct request_queue *q, char *page)
 {
 	return queue_var_show(blk_queue_dax(q), page);
@@ -659,6 +664,11 @@ static struct queue_sysfs_entry queue_wc_entry = {
 	.store = queue_wc_store,
 };
 
+static struct queue_sysfs_entry queue_fua_entry = {
+	.attr = {.name = "fua", .mode = S_IRUGO },
+	.show = queue_fua_show,
+};
+
 static struct queue_sysfs_entry queue_dax_entry = {
 	.attr = {.name = "dax", .mode = S_IRUGO },
 	.show = queue_dax_show,
@@ -708,6 +718,7 @@ static struct attribute *default_attrs[] = {
 	&queue_random_entry.attr,
 	&queue_poll_entry.attr,
 	&queue_wc_entry.attr,
+	&queue_fua_entry.attr,
 	&queue_dax_entry.attr,
 	&queue_wb_lat_entry.attr,
 	&queue_poll_delay_entry.attr,