bytemark/flexnbd-c
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Handle a failed disconnect correctly

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If the sender disconnects its socket before sending the disconnect
message, the destination should restart the migration process.  This
patch makes sure that happens.
This commit is contained in:
Alex Young
2012-07-12 09:39:39 +01:00
parent f3cebcdcd5
commit eb90308b6e
9 changed files with 154 additions and 14 deletions
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30
src/client.c
View File

@@ -166,7 +166,7 @@ int fd_read_request( int fd, struct nbd_request_raw *out_request)
/* Returns 1 if *request was filled with a valid request which we should
* try to honour. 0 otherwise. */
int client_read_request( struct client * client , struct nbd_request *out_request )
int client_read_request( struct client * client , struct nbd_request *out_request, int * disconnected )
{
NULLCHECK( client );
NULLCHECK( out_request );
@@ -199,6 +199,7 @@ int client_read_request( struct client * client , struct nbd_request *out_reques
}
if (fd_read_request(client->socket, &request_raw) == -1) {
*disconnected = 1;
switch( errno ){
case 0:
debug( "EOF while reading request" );
@@ -296,8 +297,7 @@ void client_write_init( struct client * client, uint64_t size )
* DISCONNECT and any bad request.
*/
int client_request_needs_reply( struct client * client,
struct nbd_request request,
int *should_disconnect )
struct nbd_request request )
{
debug("request type %d", request.type);
@@ -323,7 +323,7 @@ int client_request_needs_reply( struct client * client,
request.len
);
client_write_reply( client, &request, 1 );
*should_disconnect = 0;
client->disconnect = 0;
return 0;
}
break;
@@ -335,7 +335,7 @@ int client_request_needs_reply( struct client * client,
break;
case REQUEST_DISCONNECT:
debug("request disconnect");
*should_disconnect = 1;
client->disconnect = 1;
return 0;
default:
@@ -434,12 +434,13 @@ void client_reply( struct client* client, struct nbd_request request )
int client_serve_request(struct client* client)
{
struct nbd_request request;
int request_err;
int failure = 1;
int disconnected = 0;
if ( !client_read_request( client, &request ) ) { return failure; }
if ( !client_request_needs_reply( client, request, &request_err ) ) {
return request_err;
if ( !client_read_request( client, &request, &disconnected ) ) { return failure; }
if ( disconnected ) { return failure; }
if ( !client_request_needs_reply( client, request ) ) {
return client->disconnect;
}
server_lock_io( client->serve );
@@ -501,9 +502,14 @@ void* client_serve(void* client_uncast)
debug("client: stopped serving requests");
client->stopped = 1;
if ( client->entrusted ){
debug("client: control arrived" );
server_control_arrived( client->serve );
if ( client->entrusted ) {
if ( client->disconnect ){
debug("client: control arrived" );
server_control_arrived( client->serve );
}
else {
warn( "client: control transfer failed." );
}
}
FATAL_IF_NEGATIVE(

3
src/client.h
View File

@@ -30,6 +30,9 @@ struct client {
/* Have we seen a REQUEST_ENTRUST message? */
int entrusted;
/* Have we seen a REQUEST_DISCONNECT message? */
int disconnect;
};