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authorPaolo Bonzini <pbonzini@redhat.com>2012-09-18 13:31:56 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2012-09-19 15:26:29 +0200
commit7860a380ac2a9fd09a6e8f31fd9db5318fc91285 (patch)
tree3f8850554633c9d9e0c14a8926862c31ac2cef54 /qemu-nbd.c
parent0ddf08db22a9ef6b122d8c4cfe5b25d2c2c51962 (diff)
downloadqemu-arm-7860a380ac2a9fd09a6e8f31fd9db5318fc91285.tar.gz
qemu-nbd: rewrite termination conditions to use a state machine
Use a simple state machine with the following states: - RUNNING => accepting connections - TERMINATE => main loop must call nbd_export_close/put, and not accept connections anymore - TERMINATING => waiting for pending requests to finish - TERMINATED => the NBDExport has been closed Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'qemu-nbd.c')
-rw-r--r--qemu-nbd.c37
1 files changed, 27 insertions, 10 deletions
diff --git a/qemu-nbd.c b/qemu-nbd.c
index 8b87dea5f6..15bcd08123 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -41,8 +41,8 @@ static NBDExport *exp;
static int verbose;
static char *srcpath;
static char *sockpath;
-static bool sigterm_reported;
-static bool nbd_started;
+static int persistent = 0;
+static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
static int shared = 1;
static int nb_fds;
@@ -186,7 +186,7 @@ static int find_partition(BlockDriverState *bs, int partition,
static void termsig_handler(int signum)
{
- sigterm_reported = true;
+ state = TERMINATE;
qemu_notify_event();
}
@@ -269,10 +269,20 @@ static int nbd_can_accept(void *opaque)
return nb_fds < shared;
}
+static void nbd_export_closed(NBDExport *exp)
+{
+ assert(state == TERMINATING);
+ state = TERMINATED;
+}
+
static void nbd_client_closed(NBDClient *client)
{
nb_fds--;
+ if (nb_fds == 0 && !persistent && state == RUNNING) {
+ state = TERMINATE;
+ }
qemu_notify_event();
+ nbd_client_put(client);
}
static void nbd_accept(void *opaque)
@@ -282,7 +292,11 @@ static void nbd_accept(void *opaque)
socklen_t addr_len = sizeof(addr);
int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len);
- nbd_started = true;
+ if (state >= TERMINATE) {
+ close(fd);
+ return;
+ }
+
if (fd >= 0 && nbd_client_new(exp, fd, nbd_client_closed)) {
nb_fds++;
}
@@ -329,7 +343,6 @@ int main(int argc, char **argv)
int partition = -1;
int ret;
int fd;
- int persistent = 0;
bool seen_cache = false;
#ifdef CONFIG_LINUX_AIO
bool seen_aio = false;
@@ -546,7 +559,7 @@ int main(int argc, char **argv)
}
}
- exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags, NULL);
+ exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags, nbd_export_closed);
if (sockpath) {
fd = unix_socket_incoming(sockpath);
@@ -581,14 +594,18 @@ int main(int argc, char **argv)
err(EXIT_FAILURE, "Could not chdir to root directory");
}
+ state = RUNNING;
do {
main_loop_wait(false);
- } while (!sigterm_reported && (persistent || !nbd_started || nb_fds > 0));
+ if (state == TERMINATE) {
+ state = TERMINATING;
+ nbd_export_close(exp);
+ nbd_export_put(exp);
+ exp = NULL;
+ }
+ } while (state != TERMINATED);
- nbd_export_close(exp);
- nbd_export_put(exp);
bdrv_close(bs);
-
if (sockpath) {
unlink(sockpath);
}