From 4a41a2d68a684241aca96dba066e0699941b730d Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Wed, 26 Feb 2014 15:30:18 +0100 Subject: nbd: close socket if connection breaks nbd_receive_reply() is called by the event loop whenever data is available or the socket has been closed by the remote side. This patch closes the socket when an error occurs to prevent the nbd_receive_reply() handler from being called indefinitely after the connection has failed. Note that we were already correctly returning EIO for pending requests but leaving the nbd_receive_reply() handler registered resulted in high CPU consumption and a flood of error messages. Reuse nbd_teardown_connection() to close the socket. Reported-by: Zhifeng Cai Signed-off-by: Stefan Hajnoczi --- block/nbd-client.c | 33 ++++++++++++++++++--------------- 1 file changed, 18 insertions(+), 15 deletions(-) diff --git a/block/nbd-client.c b/block/nbd-client.c index 0922b78292..7d698cb619 100644 --- a/block/nbd-client.c +++ b/block/nbd-client.c @@ -43,6 +43,17 @@ static void nbd_recv_coroutines_enter_all(NbdClientSession *s) } } +static void nbd_teardown_connection(NbdClientSession *client) +{ + /* finish any pending coroutines */ + shutdown(client->sock, 2); + nbd_recv_coroutines_enter_all(client); + + qemu_aio_set_fd_handler(client->sock, NULL, NULL, NULL); + closesocket(client->sock); + client->sock = -1; +} + static void nbd_reply_ready(void *opaque) { NbdClientSession *s = opaque; @@ -78,7 +89,7 @@ static void nbd_reply_ready(void *opaque) } fail: - nbd_recv_coroutines_enter_all(s); + nbd_teardown_connection(s); } static void nbd_restart_write(void *opaque) @@ -324,7 +335,7 @@ int nbd_client_session_co_discard(NbdClientSession *client, int64_t sector_num, } -static void nbd_teardown_connection(NbdClientSession *client) +void nbd_client_session_close(NbdClientSession *client) { struct nbd_request request = { .type = NBD_CMD_DISC, @@ -332,22 +343,14 @@ static void nbd_teardown_connection(NbdClientSession *client) .len = 0 }; - nbd_send_request(client->sock, &request); - - /* finish any pending coroutines */ - shutdown(client->sock, 2); - nbd_recv_coroutines_enter_all(client); - - qemu_aio_set_fd_handler(client->sock, NULL, NULL, NULL); - closesocket(client->sock); - client->sock = -1; -} - -void nbd_client_session_close(NbdClientSession *client) -{ if (!client->bs) { return; } + if (client->sock == -1) { + return; + } + + nbd_send_request(client->sock, &request); nbd_teardown_connection(client); client->bs = NULL; -- cgit v1.2.1