Re: [PATCH 2/2] iomap: submit read bio after each extent

On Thu, Jun 25, 2026 at 10:47 AM Darrick J. Wong <[email protected]> wrote:
>
> On Thu, Jun 25, 2026 at 02:07:57PM +0200, Christoph Hellwig wrote:
>
> > So instead of adding more checks move over to a model where a bio only
> > spans a single iomap.  Change ->submit_read to be called after each
> > iteration, and pass a force argument to indicate that the bio must
> > be submitted set on the last iteration.  Switch the bio based users
> > to always submit, while keeping the single submit for fuse.
>
> Is fuse the sole reason for the "force" parameter to exist?  I wonder if
> fuse could drop its submit_read function and call fuse_send_readpages
> after the iomap_read{ahead,folio} function returns?
>

Yes, that works. I think that's a good idea. fuse only needs
submit_read logic for readahead. The change would just be:

--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -953,19 +953,8 @@ static int
fuse_iomap_read_folio_range_async(const struct iomap_iter *iter,
        return ret;
 }

-static void fuse_iomap_submit_read(const struct iomap_iter *iter,
-               struct iomap_read_folio_ctx *ctx)
-{
-       struct fuse_fill_read_data *data = ctx->read_ctx;
-
-       if (data->ia)
-               fuse_send_readpages(data->ia, data->file, data->nr_bytes,
-                                   data->fc->async_read);
-}
-
 static const struct iomap_read_ops fuse_iomap_read_ops = {
        .read_folio_range = fuse_iomap_read_folio_range_async,
-       .submit_read = fuse_iomap_submit_read,
 };

 static int fuse_read_folio(struct file *file, struct folio *folio)
@@ -1089,6 +1078,9 @@ static void fuse_readahead(struct readahead_control *rac)
                return;

        iomap_readahead(&fuse_iomap_ops, &ctx, NULL);
+       if (data.ia)
+               fuse_send_readpages(data.ia, data.file, data.nr_bytes,
+                                   fc->async_read);
 }


If this fix needs to go into 7.2 though, maybe it makes sense to land
the v1 implementation [1] + the xfs integrity fix now and do the fuse
change later?

Thanks,
Joanne

[1] https://lore.kernel.org/linux-fsdevel/[email protected]/