On Tue, Aug 27, 2019 at 12:38:28PM -0400, Vivek Goyal wrote: > > For bdev_dax_pgoff > > I'd much rather have the partition offset if there is on in the daxdev > > somehow so that we can get rid of the block device entirely. > > IIUC, there is one block_device per partition while there is only one > dax_device for the whole disk. So we can't directly move bdev logical > offset into dax_device. Well, then we need to find a way to get partitions for dax devices, as we really should not expect a block device hiding behind a dax dev. That is just a weird legacy assumption - block device need to layer on top of the dax device optionally. > > We probably could put this in "iomap" and leave it to filesystems to > report offset into dax_dev in iomap that way dax generic code does not > have to deal with it. But that probably will be a bigger change. And where would the file system get that information from? > commit 4b0228fa1d753f77fe0e6cf4c41398ec77dfbd2a > Author: Vishal Verma <vishal.l.verma@xxxxxxxxx> > Date: Thu Apr 21 15:13:46 2016 -0400 > > dax: for truncate/hole-punch, do zeroing through the driver if possible > > IIUC, they are doing it so that they can clear gendisk->badblocks list. > > So even if there is pure dax way to do it, there will have to some > involvment of block layer to clear gendisk->badblocks list. Once again we need to move that list to the dax device, as the assumption that there is a block device associated with the dax dev is flawed. > I am not sure I fully understand your suggestion. But I am hoping its > not a must for these changes to make a progress. For now, I will drop > change to dax_range_is_aligned(). Well, someone needs to clean this mess up, and as you have an actual real life example of a dax dev without the block device I think the burden naturally falls on you.
