On Wed, Feb 1, 2017 at 12:08 AM, Christoph Hellwig [off-list ref] wrote:

On Mon, Jan 30, 2017 at 10:29:12AM -0800, Dan Williams wrote:

quoted

On Mon, Jan 30, 2017 at 4:26 AM, Christoph Hellwig [off-list ref] wrote:

quoted

On Sat, Jan 28, 2017 at 12:37:14AM -0800, Dan Williams wrote:

quoted

This is in preparation for removing the ->direct_access() method from
block_device_operations.

I don't think mount_bdev has any business knowing about DAX.
Just call dax_get_by_host manually from the affected file systems for
now, and in the future we can have a pure-DAX mount_dax helper.

Ok, since we already need dax_get_by_host() in the blkdev_writepages()
path I can sprinkle a few more of those calls and leave mount_bdev
alone.

Huh?  I thought we stopped using DAX I/O for the block device nodes
a while ago?

Oh, yeah, you're right. The blkdev_writepages() call to
dax_writeback_mapping_range() is likely leftover dead code. I'll clean
it up.