On Mon, Nov 09, 2015 at 07:29:21PM +0800, Ming Lei wrote: > > It's fine to use --direct-io as toggle, but it would be nice to > > support it also when initialize the device. > > OK, looks a good idea, but we still need to support the standalone > command for direct-io for the case of 'mount -o loop'. Sure, I understand this use-case. I have talked bout loop_set_fd(), maybe all we need is: diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 423f4ca..22642a0 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -925,7 +925,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode, set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0); - lo->use_dio = false; + lo->use_dio = (lo_flags & LO_FLAGS_DIRECT_IO); lo->lo_blocksize = lo_blocksize; lo->lo_device = bdev; lo->lo_flags = lo_flags; then we can a little bit modify your losetup.c patches and support --direct-io also for A_CREATE. Karel -- Karel Zak <kzak@xxxxxxxxxx> http://karelzak.blogspot.com -- To unsubscribe from this list: send the line "unsubscribe util-linux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html