Re: [PATCHSET 02/12] fstests: fix logwrites zeroing

Christoph Hellwig
2025-02-19T06:20:53Z

On Tue, Feb 18, 2025 at 10:13:36PM -0800, Darrick J. Wong wrote:
> Alternately we could make the log replay program call
> fallocate(PUNCH_HOLE) on the block device before trying
> fallocate(ZERO_RANGE) because AFAICT punch-hole has always called
> blkdev_issue_zeroout with NOFALLBACK. The downside is that fallocate
> for block devices came long after BLKDISCARD/BLKZEROOUT so we can't
> remove the BLK* ioctl calls without losing some coverage.

FALLOC_FL_ZERO_RANGE on block devices has been around since 2016, so I
don't think that's a problem. The problem is more that it isn't
supported on dm-thin at all.