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

From: David Howells <dhowells@redhat.com>
To: Jeff Layton <jlayton@kernel.org>
Cc: dhowells@redhat.com, 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 14:57:57 +0000	[thread overview]
Message-ID: <1130437.1642777077@warthog.procyon.org.uk> (raw)
In-Reply-To: <20220121141838.110954-3-jlayton@kernel.org>

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