Re: [PATCH 19/34] xfs: simplify xfs_bmap_punch_delalloc_range

On Wed, May 23, 2018 at 12:17:11PM -0400, Brian Foster wrote:

Mostly looks Ok, but I'm not following what this get_extent() call is
for..? It also doesn't look like it would always do the right thing with
sub-page blocks. Consider a page with a couple discontig delalloc blocks
that happen to be the first extents in the file. The first
xfs_bmap_del_extent_delay() would do:

	xfs_iext_remove(ip, icur, state);
	xfs_iext_prev(ifp, icur);

... which I think sets cur->pos to -1, causes the get_extent() to fail
and thus fails to remove the subsequent delalloc blocks. Hm?

True.  This function should probably walk the extent list backwards
like xfs_bunmapi as that is the model that xfs_bmap_del_extent_* is
built around.