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[Qemu-devel] [PATCH 09/12] qemu-nbd: rewrite termination conditions to u
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 09/12] qemu-nbd: rewrite termination conditions to use a state machine |
Date: |
Wed, 19 Sep 2012 15:49:53 +0200 |
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 <address@hidden>
---
qemu-nbd.c | 37 +++++++++++++++++++++++++++----------
1 file modificato, 27 inserzioni(+), 10 rimozioni(-)
diff --git a/qemu-nbd.c b/qemu-nbd.c
index 8b87dea..15bcd08 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);
}
--
1.7.12
- [Qemu-devel] [PULL 00/12] NBD patches for 2012-09-22, Paolo Bonzini, 2012/09/19
- [Qemu-devel] [PATCH 01/12] nbd: add more constants, Paolo Bonzini, 2012/09/19
- [Qemu-devel] [PATCH 03/12] nbd: do not close BlockDriverState in nbd_export_close, Paolo Bonzini, 2012/09/19
- [Qemu-devel] [PATCH 02/12] nbd: pass NBDClient to nbd_send_negotiate, Paolo Bonzini, 2012/09/19
- [Qemu-devel] [PATCH 04/12] nbd: make refcount interface public, Paolo Bonzini, 2012/09/19
- [Qemu-devel] [PATCH 05/12] nbd: do not leak nbd_trip coroutines when a connection is torn down, Paolo Bonzini, 2012/09/19
- [Qemu-devel] [PATCH 06/12] nbd: add reference counting to NBDExport, Paolo Bonzini, 2012/09/19
- [Qemu-devel] [PATCH 08/12] nbd: add notification for closing an NBDExport, Paolo Bonzini, 2012/09/19
- [Qemu-devel] [PATCH 11/12] nbd: negotiate with named exports, Paolo Bonzini, 2012/09/19
- [Qemu-devel] [PATCH 07/12] nbd: track clients into NBDExport, Paolo Bonzini, 2012/09/19
- [Qemu-devel] [PATCH 09/12] qemu-nbd: rewrite termination conditions to use a state machine,
Paolo Bonzini <=
- [Qemu-devel] [PATCH 10/12] nbd: register named exports, Paolo Bonzini, 2012/09/19
- [Qemu-devel] [PATCH 12/12] nbd: add nbd_export_get_blockdev, Paolo Bonzini, 2012/09/19
- Re: [Qemu-devel] [PULL 00/12] NBD patches for 2012-09-22, Anthony Liguori, 2012/09/25