Hi Antony,
I think I may have a fix already lurking on my netfs-writeback branch for the
next merge window. Can you try the attached?
David
---
Don't revert the I/O iterator before returning from p9_client_read_once().
netfslib doesn't require the reversion and nor doed 9P directory reading.
Make p9_client_read() use a temporary iterator to call down into
p9_client_read_once(), and advance that by the amount read.
Reported-by: Antony Antony <antony@xxxxxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Eric Van Hensbergen <ericvh@xxxxxxxxxx>
cc: Latchesar Ionkov <lucho@xxxxxxxxxx>
cc: Dominique Martinet <asmadeus@xxxxxxxxxxxxx>
cc: Christian Schoenebeck <linux_oss@xxxxxxxxxxxxx>
cc: v9fs@xxxxxxxxxxxxxxx
cc: netfs@xxxxxxxxxxxxxxx
cc: linux-fsdevel@xxxxxxxxxxxxxxx
---
net/9p/client.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/net/9p/client.c b/net/9p/client.c
index 5cd94721d974..be59b0a94eaf 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -1519,13 +1519,15 @@ p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
*err = 0;
while (iov_iter_count(to)) {
+ struct iov_iter tmp = *to;
int count;
- count = p9_client_read_once(fid, offset, to, err);
+ count = p9_client_read_once(fid, offset, &tmp, err);
if (!count || *err)
break;
offset += count;
total += count;
+ iov_iter_advance(to, count);
}
return total;
}
@@ -1567,16 +1569,12 @@ p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
}
if (IS_ERR(req)) {
*err = PTR_ERR(req);
- if (!non_zc)
- iov_iter_revert(to, count - iov_iter_count(to));
return 0;
}
*err = p9pdu_readf(&req->rc, clnt->proto_version,
"D", &received, &dataptr);
if (*err) {
- if (!non_zc)
- iov_iter_revert(to, count - iov_iter_count(to));
trace_9p_protocol_dump(clnt, &req->rc);
p9_req_put(clnt, req);
return 0;
@@ -1596,8 +1594,6 @@ p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
p9_req_put(clnt, req);
return n;
}
- } else {
- iov_iter_revert(to, count - received - iov_iter_count(to));
}
p9_req_put(clnt, req);
return received;
