Re: READ_PLUS in NetFS? Re: [PATCH v10 30/35] netfs: Simplify read abandonment

[David Howells]

Aurélien Couderc <aurelien.couderc2002@xxxxxxxxx> wrote:

> What about READ_PLUS, i.e. sparse file reads? If you do this kind of
> work of handling partial abandonment, can such a work also benefit
> READ_PLUS?

READ_PLUS is NFS, right?

I'm not sure it would particularly help or hinder.

The VFS/VM only asks to read contiguous regions and netfslib breaks that up
into subrequests, but currently netfslib doesn't know anything about sparse
reads.  What I'm looking at with Ceph, for example, is that Ceph knows where
the gaps are and will clear them before terminating the subrequest.

Partial abandonment is for when some sort of fatal error occurs and we cannot
finish the request.

David