bytemark/flexnbd-c
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Added mirror write barrier / final pass stuff & clean exit afterwards.

Browse Source 
Plenty of code documentation.
This commit is contained in:
Matthew Bloch
2012-05-29 04:03:28 +01:00
parent dcb1633b8b
commit ab0dfb5eca
7 changed files with 323 additions and 28 deletions
Download Patch File Download Diff File Expand all files Collapse all files

92
serve.c
View File

@@ -23,6 +23,14 @@ static inline void dirty(struct mode_serve_params *serve, off64_t from, int len)
bitset_set_range(serve->mirror->dirty_map, from, len);
}
int server_detect_closed(struct mode_serve_params* serve)
{
int errno_old = errno;
int result = fcntl(serve->server, F_GETFD, 0) < 0;
errno = errno_old;
return result;
}
/**
* So waiting on client->socket is len bytes of data, and we must write it all
* to client->mapped. However while doing do we must consult the bitmap
@@ -126,7 +134,17 @@ int client_serve_request(struct client_params* client)
off64_t offset;
struct nbd_request request;
struct nbd_reply reply;
fd_set fds;
FD_ZERO(&fds);
FD_SET(client->socket, &fds);
FD_SET(client->serve->close_signal[0], &fds);
CLIENT_ERROR_ON_FAILURE(select(FD_SETSIZE, &fds, NULL, NULL, NULL),
"select() failed");
if (FD_ISSET(client->serve->close_signal[0], &fds))
return 1;
if (readloop(client->socket, &request, sizeof(request)) == -1) {
if (errno == 0) {
debug("EOF reading request");
@@ -176,6 +194,14 @@ int client_serve_request(struct client_params* client)
"Problem with I/O lock"
);
if (server_detect_closed(client->serve)) {
CLIENT_ERROR_ON_FAILURE(
pthread_mutex_unlock(&client->serve->l_io),
"Problem with I/O unlock"
);
return 1;
}
switch (be32toh(request.type))
{
case REQUEST_READ:
@@ -269,18 +295,20 @@ void* client_serve(void* client_uncast)
"Couldn't close socket %d",
client->socket
);
close(client->socket);
close(client->fileno);
munmap(client->mapped, client->serve->size);
free(client);
return NULL;
}
static int testmasks[9] = { 0,128,192,224,240,248,252,254,255 };
/** Test whether AF_INET or AF_INET6 sockaddr is included in the given access
* control list, returning 1 if it is, and 0 if not.
*/
int is_included_in_acl(int list_length, struct ip_and_mask (*list)[], struct sockaddr* test)
{
int i;
@@ -335,6 +363,7 @@ int is_included_in_acl(int list_length, struct ip_and_mask (*list)[], struct soc
return 0;
}
/** Prepares a listening socket for the NBD server, binding etc. */
void serve_open_server_socket(struct mode_serve_params* params)
{
int optval=1;
@@ -362,6 +391,10 @@ void serve_open_server_socket(struct mode_serve_params* params)
);
}
/** We can only accommodate MAX_NBD_CLIENTS connections at once. This function
* goes through the current list, waits for any threads that have finished
* and returns the next slot free (or -1 if there are none).
*/
int cleanup_and_find_client_slot(struct mode_serve_params* params)
{
int slot=-1, i;
@@ -399,6 +432,10 @@ int cleanup_and_find_client_slot(struct mode_serve_params* params)
return slot;
}
/** Dispatch function for accepting an NBD connection and starting a thread
* to handle it. Rejects the connection if there is an ACL, and the far end's
* address doesn't match, or if there are too many clients already connected.
*/
void accept_nbd_client(struct mode_serve_params* params, int client_fd, struct sockaddr* client_address)
{
struct client_params* client_params;
@@ -441,6 +478,7 @@ void accept_nbd_client(struct mode_serve_params* params, int client_fd, struct s
debug("nbd thread %d started (%s)", (int) params->nbd_client[slot].thread, s_client_address);
}
/** Accept either an NBD or control socket connection, dispatch appropriately */
void serve_accept_loop(struct mode_serve_params* params)
{
while (1) {
@@ -451,18 +489,19 @@ void serve_accept_loop(struct mode_serve_params* params)
FD_ZERO(&fds);
FD_SET(params->server, &fds);
FD_SET(params->close_signal[0], &fds);
if (params->control_socket_name)
FD_SET(params->control, &fds);
SERVER_ERROR_ON_FAILURE(
select(FD_SETSIZE, &fds, NULL, NULL, NULL),
"select() failed"
);
SERVER_ERROR_ON_FAILURE(select(FD_SETSIZE, &fds,
NULL, NULL, NULL), "select() failed");
if (FD_ISSET(params->close_signal[0], &fds))
return;
activity_fd = FD_ISSET(params->server, &fds) ? params->server :
params->control;
client_fd = accept(activity_fd, &client_address, &socklen);
SERVER_ERROR_ON_FAILURE(client_fd, "accept() failed");
SERVER_ERROR_ON_FAILURE(
pthread_mutex_lock(&params->l_accept),
@@ -481,6 +520,9 @@ void serve_accept_loop(struct mode_serve_params* params)
}
}
/** Initialisation function that sets up the initial allocation map, i.e. so
* we know which blocks of the file are allocated.
*/
void serve_init_allocation_map(struct mode_serve_params* params)
{
int fd = open(params->filename, O_RDONLY);
@@ -495,14 +537,50 @@ void serve_init_allocation_map(struct mode_serve_params* params)
close(fd);
}
/** Closes sockets, frees memory and waits for all client threads to finish */
void serve_cleanup(struct mode_serve_params* params)
{
int i;
close(params->server);
close(params->control);
if (params->acl)
free(params->acl);
//free(params->filename);
if (params->control_socket_name)
//free(params->control_socket_name);
pthread_mutex_destroy(&params->l_accept);
pthread_mutex_destroy(&params->l_io);
if (params->proxy_fd);
close(params->proxy_fd);
close(params->close_signal[0]);
close(params->close_signal[1]);
free(params->block_allocation_map);
if (params->mirror)
debug("mirror thread running! this should not happen!");
for (i=0; i < MAX_NBD_CLIENTS; i++) {
void* status;
if (params->nbd_client[i].thread != 0) {
debug("joining thread %d", i);
pthread_join(params->nbd_client[i].thread, &status);
}
}
}
/** Full lifecycle of the server */
void do_serve(struct mode_serve_params* params)
{
pthread_mutex_init(&params->l_accept, NULL);
pthread_mutex_init(&params->l_io, NULL);
SERVER_ERROR_ON_FAILURE(pipe(params->close_signal) , "pipe failed");
serve_open_server_socket(params);
serve_open_control_socket(params);
serve_init_allocation_map(params);
serve_accept_loop(params);
serve_cleanup(params);
}