On Apr 17, 2018, at 10:57 AM, Darrick J. Wong <darrick.wong(a)oracle.com&gt; wrote: > > On Tue, Apr 17, 2018 at 09:53:47AM -0700, Dan Williams wrote: >> On Tue, Apr 17, 2018 at 9:10 AM, Christoph Hellwig <hch(a)infradead.org&gt; wrote: >>> On Tue, Apr 17, 2018 at 10:40:59PM +0800, Xiong Zhou wrote: >>>> We got these in v4.17-rc1: >>>> 6e2608d xfs, dax: introduce xfs_dax_aops >>>> fb094c9 ext2, dax: introduce ext2_dax_aops >>>> 5f0663b ext4, dax: introduce ext4_dax_aops >>>> >>>> And we don't have ->bmap call in these aops, which may lead >>>> to the ioctl call failure. >>>> >>>> Do we have any plan of adding/supporting it ? >>>> >>>> xfstests generic/223 covers this issue. If we are not going >>>> to support this call for dax, we need to fix the testcase. >>> >>> Not supporting ->bmap is a good thing as it is hightly dangerous. >> >> I take this to mean "don't fix, it is another casualty of dax being >> experimental and it won't be coming back". I can get on board with >> that. >> >> Otherwise, I was about to send a series adding bmap to {xfs,ext2,ext4}_dax_ops. > > Frankly I'd rather see the swapfile code learn how to iomap and then we > can get rid of bmap in xfs entirely. Is anyone still using LILO to boot? It needed FIBMAP support to map the kernel image for booting. I don't know if Grub needs FIBMAP support for the early boot stages or not (it has minimal filesystem support in the later stages), but it would be a shame if it wasn't possible to boot an all-NVRAM system as a result of a missing ->bmap() method. Alternately, convince the Grub folks to use FIEMAP if that is available...

Cheers, Andreas