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]>
This commit is contained in:
Anand Jain 2017-04-06 11:22:53 +08:00 • committed by David Sterba
commit c2a9c7ab47

View file

@ -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)