Re: [RFC PATCH v5 0/4] migrates ocfs2 DIO from buffer_head to iomap

[Heming Zhao]

On 11/6/26 18:46, Christoph Hellwig wrote:
> s/migrates/migrate/ I think.
>
> On Thu, Nov 05, 2026 at 03:19:24PM +0800, Heming Zhao wrote:
> > To simplify iomap development, we currently adopt the simplest approach:
> > retaining the buffer_head style, where only one cluster is allocated
> > per iomap_begin() call.
>
> Do you mean you'd otherwise need changes to the core iomap code?
> Or do I misunderstand the sentence.

Apologies for my English.
"To simplify iomap development" should be "To simplify ocfs2 iomap development".

Because the ocfs2 buffer_head path uses "struct ocfs2_dio_write_ctxt *dwc"
to pass dio unwritten info from the dio get_block phase (ocfs2_dio_wr_get_block())
to the end_io phase (ocfs2_dio_end_io_write()).

However, iomap clears iocb->private before the iomap_dio_ops end_io callback,
which makes it impossible to reuse the current ocfs2 buffer_head end_io function.

- Heming