Re: [PATCH v3 2/3] ceph: Make ceph_netfs_issue_op() handle inlined data

From: Jeff Layton <jlayton@kernel.org>
To: David Howells <dhowells@redhat.com>
Cc: ceph-devel@vger.kernel.org, idryomov@gmail.com,
	linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v3 2/3] ceph: Make ceph_netfs_issue_op() handle inlined data
Date: Fri, 21 Jan 2022 10:18:56 -0500	[thread overview]
Message-ID: <aa6ecc69eeb4c1e25c11f37f86a7796e7c40997b.camel@kernel.org> (raw)
In-Reply-To: <1130437.1642777077@warthog.procyon.org.uk>

On Fri, 2022-01-21 at 14:57 +0000, David Howells wrote:
> Jeff Layton <jlayton@kernel.org> wrote:
> 
> > +	len = iinfo->inline_len;
> > +	iov_iter_xarray(&iter, READ, &rreq->mapping->i_pages, subreq->start, len);
> > +	err = copy_to_iter(iinfo->inline_data, len, &iter);
> 
> I think this is probably wrong.  It will read the entirety of the inline data
> into the buffer, even if it's bigger than the buffer and you need to offset
> pointer into the buffer.
> 
> You need to limit it to subreq->len.  Maybe:
> 
> 	len = min_t(size_t, iinfo->inline_len - subreq->start, subreq->len);
> 	iov_iter_xarray(&iter, READ, &rreq->mapping->i_pages,
> 			subreq->start, len);
> 	err = copy_to_iter(iinfo->inline_data + subreq->start, len, &iter);
> 
> David
> 

Good point. I'll make that change and re-test, but it makes sense.
-- 
Jeff Layton <jlayton@kernel.org>