Re: ioctl FIBMAP for dax gone in v4.17-rc1

Dan Williams
2018-04-17T16:53:48Z

On Tue, Apr 17, 2018 at 9:10 AM, Christoph Hellwig <hch@infradead.org> 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.