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[PULL 06/13] nbd: remove peppering of nbd_client_connected
From: |
Eric Blake |
Subject: |
[PULL 06/13] nbd: remove peppering of nbd_client_connected |
Date: |
Tue, 26 Apr 2022 15:15:07 -0500 |
From: Paolo Bonzini <pbonzini@redhat.com>
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>
---
block/nbd.c | 17 ++++-------------
1 file changed, 4 insertions(+), 13 deletions(-)
diff --git a/block/nbd.c b/block/nbd.c
index 3a6e60920304..326546f6cd4c 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;
- }
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;
}
--
2.35.1
- [PULL 00/13] NBD patches through 2022-04-26, Eric Blake, 2022/04/26
- [PULL 02/13] qapi: nbd-export: allow select bitmaps by node/name pair, Eric Blake, 2022/04/26
- [PULL 09/13] nbd: code motion and function renaming, Eric Blake, 2022/04/26
- [PULL 01/13] qapi: rename BlockDirtyBitmapMergeSource to BlockDirtyBitmapOrStr, Eric Blake, 2022/04/26
- [PULL 04/13] nbd: safeguard against waking up invalid coroutine, Eric Blake, 2022/04/26
- [PULL 06/13] nbd: remove peppering of nbd_client_connected,
Eric Blake <=
- [PULL 12/13] nbd: document what is protected by the CoMutexes, Eric Blake, 2022/04/26
- [PULL 11/13] nbd: take receive_mutex when reading requests[].receiving, Eric Blake, 2022/04/26
- [PULL 05/13] nbd: mark more coroutine_fns, Eric Blake, 2022/04/26
- [PULL 08/13] nbd: use a QemuMutex to synchronize yanking, reconnection and coroutines, Eric Blake, 2022/04/26
- [PULL 03/13] iotests/223: check new possibility of exporting bitmaps by node/name, Eric Blake, 2022/04/26
- [PULL 07/13] nbd: keep send_mutex/free_sema handling outside nbd_co_do_establish_connection, Eric Blake, 2022/04/26
- [PULL 13/13] qemu-nbd: Pass max connections to blockdev layer, Eric Blake, 2022/04/26
- [PULL 10/13] nbd: move s->state under requests_lock, Eric Blake, 2022/04/26
- Re: [PULL 00/13] NBD patches through 2022-04-26, Richard Henderson, 2022/04/26