btrfs: check if the device is flush capable

The block layer call chain from submit_bio will check if the write cache is enabled for the given queue before submitting the flush. This will add a code to fail fast if its not. Signed-off-by: Anand Jain <[email protected]> Reviewed-by: David Sterba <[email protected]> [ updated changelog to reflect current code stat, blkdev_issue_flush is not used yet ] Signed-off-by: David Sterba <[email protected]>
tdeneau · Apr 18, 2017 · c2a9c7a · c2a9c7a
1 parent 13e88e1
commit c2a9c7a
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
@@ -3518,9 +3518,13 @@ static void btrfs_end_empty_barrier(struct bio *bio)
  */
 static int write_dev_flush(struct btrfs_device *device, int wait)
 {
+	struct request_queue *q = bdev_get_queue(device->bdev);
 	struct bio *bio;
 	int ret = 0;
 
+	if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags))
+		return 0;
+
 	if (wait) {
 		bio = device->flush_bio;
 		if (!bio)