Re: [PATCH] xfs: fix BUG_ON in xfs_getbmap()

[Christoph Hellwig]

On Mon, Mar 27, 2023 at 08:15:24AM -0700, Darrick J. Wong wrote:
> > There's issue as follows:
> > XFS: Assertion failed: (bmv->bmv_iflags & BMV_IF_DELALLOC) != 0, file: fs/xfs/xfs_bmap_util.c, line: 329
> 
> Why not get rid of the assertion?  It's not like it changes the course
> of the code flow -- userspace still gets told there's a delalloc extent.
> 
> Or, if the assert does serve some purpose, then do we need to take
> the mmaplock for cow fork reporting too?

Looking at the COW fork reporting I think it's actually even more
broken as it never tried to flush data to start with.  But COW
report is a DEBUG only feature, so maybe forcing or requiring
BMV_IF_DELALLOC there would make a whole lot of sense.