Re: [PATCH] xfs: fix the judgment of whether the file already has extents

[Christoph Hellwig]

On Sun, Oct 27, 2024 at 02:01:16AM +0800, alexjlzheng@xxxxxxxxx wrote:
> From: Jinliang Zheng <alexjlzheng@xxxxxxxxxxx>
> 
> When we call create(), lseek() and write() sequentially, offset != 0
> cannot be used as a judgment condition for whether the file already
> has extents.
> 
> This patch uses prev.br_startoff instead of offset != 0.

This changed the predicate from "are we at offset 0" to "are there
any allocations before that".  That's a pretty big semantic change.
Maybe a good one, maybe not.  Can you explain what workload it helps
you with?