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nbd: remove peppering of nbd_client_connected

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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 <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220414175756.671165-4-pbonzini@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@openvz.org>
Reviewed-by: Lukas Straub <lukasstraub2@web.de>
Signed-off-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Paolo Bonzini 2022-04-14 19:57:50 +02:00 committed by Eric Blake
parent 0c43c6fc89
commit 172f5f1a40
1 changed files with 4 additions and 13 deletions
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17
block/nbd.c
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@ -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;
}
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) {
goto break_loop;
}