Re: [PATCH] ceph: parallelize object copy in ceph_do_objects_copy()

Hi Alex,

Thanks for the feedback. You are right, those are good points.

Let me fix them and send the V2.

Thanks
- Xiubo

On Thu, 13 Aug 2026 at 05:09, Alex Markuze <[email protected]> wrote:
>
> Hi Xiubo,
>
> Thanks for the patch, the idea is sound but there are a few correctness
> issues that need fixing:
>
> The drain loop walks past the valid window on error — it dereferences
> request pointers beyond the tail of the in-flight window, which are
> either freed or uninitialized depending on where the failure occurred.
>
> The window size is read from copyfrom_max_inflight on every iteration.
> A concurrent sysfs write can change it mid-flight, causing the loop
> bounds to shift while requests are already in-flight.
>
> If a request allocation fails partway through, the error return masks
> any I/O errors that were already recorded for earlier in-flight
> requests.
>
> There's also a design issue for mid-file copies: parallel writes can
> modify the destination beyond the position implied by a short source
> count before the short is detected.
>
> Could you respin with these fixed?
>
> --
> Alex Markuze
>