Re: [PATCH v2 1/4] iomap: don't resubmit an ioend after ->writeback_submit() failed

[Andrea Parri <parri.andrea@gmail.com>]

On Thu, Sep 24, 2026 at 11:49:10AM -0700, Darrick J. Wong wrote:
> I looked around the codebase and saw that iomap_writepages also calls
> ->writeback_submit.  Does that need to null out wb_ctx?
> 
> My guess is that none of the callers do anything with wpc after
> iomap_writepages returns so it's not harming anyone, but we should drop
> the stale context too, right?

Your guess is right: that ->writeback_submit() call is the last thing
iomap_writepages() does, and all of its callers (xfs, gfs2, zonefs,
exfat, fuse, ntfs, ntfs3) have the wpc on the stack for that single
call, so wb_ctx is never looked at again.  Christoph made the same
point on v1 [1], and the last paragraph of the commit message now
spells it out.

Clearing it there as well would be harmless but dead code, so I'd
rather leave it out; happy to add it if you feel strongly about it.

[1] https://lore.kernel.org/all/arITXTsUhrA0N-qr@infradead.org/

Thanks!
  Andrea