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: David Howells <dhowells@xxxxxxxxxx>
cc: Jeff Layton <jlayton@xxxxxxxxxx>
cc: netfs@xxxxxxxxxxxxxxx
cc: linux-fsdevel@xxxxxxxxxxxxxxx
---
fs/netfs/write_issue.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/fs/netfs/write_issue.c b/fs/netfs/write_issue.c
index 0929d9fd4ce7..6293f547e4c3 100644
--- a/fs/netfs/write_issue.c
+++ b/fs/netfs/write_issue.c
@@ -317,6 +317,7 @@ 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;
@@ -472,7 +473,12 @@ 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;
@@ -487,8 +493,8 @@ 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)
