14.04.2022 20:57, Paolo Bonzini wrote:
It is unnecessary to check nbd_client_connected() because every time
s->state is moved out of NBD_CLIENT_CONNECTED the socket is shut down
and all coroutines are resumed.
The only case where it was actually needed is when the NBD
server disconnects and there is no reconnect-delay. In that
case, nbd_receive_replies() does not set s->reply.handle and
nbd_co_do_receive_one_chunk() cannot continue. For that one case,
check the return value of nbd_receive_replies().
As to the others:
* nbd_receive_replies() can put the current coroutine to sleep if another
reply is ongoing; then it will be woken by nbd_channel_error(), called
by the ongoing reply. Or it can try itself to read a reply header and
fail, thus calling nbd_channel_error() itself.
* nbd_co_send_request() will write the body of the request and fail
* nbd_reply_chunk_iter_receive() will call nbd_co_receive_one_chunk()
and then nbd_co_do_receive_one_chunk(), which will handle the failure as
above; or it will just detect a previous call to nbd_iter_channel_error()
via iter->ret < 0.
Reviewed-by: Eric Blake <ebl...@redhat.com>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
block/nbd.c | 17 ++++-------------
1 file changed, 4 insertions(+), 13 deletions(-)
diff --git a/block/nbd.c b/block/nbd.c
index 3cc4ea4430..a30603ce87 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -409,10 +409,6 @@ static coroutine_fn int nbd_receive_replies(BDRVNBDState
*s, uint64_t handle)
return 0;
}
- if (!nbd_client_connected(s)) {
- return -EIO;
- }
-
if (s->reply.handle != 0) {
/*
* Some other request is being handled now. It should already be
@@ -512,7 +508,7 @@ static int coroutine_fn
nbd_co_send_request(BlockDriverState *bs,
if (qiov) {
qio_channel_set_cork(s->ioc, true);
rc = nbd_send_request(s->ioc, request);
- if (nbd_client_connected(s) && rc >= 0) {
+ if (rc >= 0) {
if (qio_channel_writev_all(s->ioc, qiov->iov, qiov->niov,
NULL) < 0) {
rc = -EIO;
@@ -829,8 +825,8 @@ static coroutine_fn int nbd_co_do_receive_one_chunk(
}
*request_ret = 0;
- nbd_receive_replies(s, handle);
- if (!nbd_client_connected(s)) {
+ ret = nbd_receive_replies(s, handle);
+ if (ret < 0) {
error_setg(errp, "Connection closed");
return -EIO;
}
@@ -982,11 +978,6 @@ static bool nbd_reply_chunk_iter_receive(BDRVNBDState *s,
NBDReply local_reply;
NBDStructuredReplyChunk *chunk;
Error *local_err = NULL;
- if (!nbd_client_connected(s)) {
- error_setg(&local_err, "Connection closed");
- nbd_iter_channel_error(iter, -EIO, &local_err);
- goto break_loop;
- }
Probably we should still check iter->ret here. It's strange to start new
iteration, when user set iter->ret in previous iteration of
NBD_FOREACH_REPLY_CHUNK()
Or, maybe we should set iter->done in nbd_iter_channel_error ?
if (iter->done) {
/* Previous iteration was last. */
@@ -1007,7 +998,7 @@ static bool nbd_reply_chunk_iter_receive(BDRVNBDState *s,
}
/* Do not execute the body of NBD_FOREACH_REPLY_CHUNK for simple reply. */
- if (nbd_reply_is_simple(reply) || !nbd_client_connected(s)) {
+ if (nbd_reply_is_simple(reply) || iter->ret < 0) {
And then here, may be we can just goto break_loop from previous "if (ret < 0)".
Then we'll not have to check iter->ret.
goto break_loop;
}
anyway:
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsement...@openvz.org>
(a bit weak, as it really hard to imagine all these paths and possible
consequences :/
--
Best regards,
Vladimir
