Unverified Commit 9fffa4e9 authored by David Howells's avatar David Howells Committed by Christian Brauner
Browse files

netfs: Advance iterator correctly rather than jumping it 



In netfs_write_folio(), use iov_iter_advance() to advance the folio as we
split bits of it off to subrequests rather than manually jumping the
->iov_offset value around.  This becomes more problematic when we use a
bounce buffer made out of single-page folios to cover a multipage pagecache
folio.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/2238548.1727424522@warthog.procyon.org.uk


cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent ff98751b

fs/netfs/write_issue.c

+9 −3
Original line number Diff line number Diff line
@@ -307,6 +307,7 @@ static int netfs_write_folio(struct netfs_io_request *wreq, 
	struct netfs_io_stream *stream;

	struct netfs_group *fgroup; /* TODO: Use this with ceph */

	struct netfs_folio *finfo;

	size_t iter_off = 0;

	size_t fsize = folio_size(folio), flen = fsize, foff = 0;

	loff_t fpos = folio_pos(folio), i_size;

	bool to_eof = false, streamw = false;
@@ -462,7 +463,12 @@ static int netfs_write_folio(struct netfs_io_request *wreq, 
		if (choose_s < 0)

			break;

		stream = &wreq->io_streams[choose_s];

		wreq->io_iter.iov_offset = stream->submit_off;



		/* Advance the iterator(s). */

		if (stream->submit_off > iter_off) {

			iov_iter_advance(&wreq->io_iter, stream->submit_off - iter_off);

			iter_off = stream->submit_off;

		}



		atomic64_set(&wreq->issued_to, fpos + stream->submit_off);

		stream->submit_extendable_to = fsize - stream->submit_off;
@@ -477,8 +483,8 @@ static int netfs_write_folio(struct netfs_io_request *wreq, 
			debug = true;

	}



	wreq->io_iter.iov_offset = 0;

	iov_iter_advance(&wreq->io_iter, fsize);

	if (fsize > iter_off)

		iov_iter_advance(&wreq->io_iter, fsize - iter_off);

	atomic64_set(&wreq->issued_to, fpos + fsize);



	if (!debug)