Attachment 9466 Details for Bug 10284 – Patch for 4.1.1

Patch for 4.1.1

look (text/plain), 6.27 KB, created by Volker Lendecke on 2013-11-22 08:34:47 UTC

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Creator: Volker Lendecke

Created: 2013-11-22 08:34:47 UTC

Size: 6.27 KB

patch

obsolete

>From b11448af2c3f6c9a49af0e4e70686f3ea59afc5d Mon Sep 17 00:00:00 2001
>From: Volker Lendecke <vl@samba.org>
>Date: Thu, 21 Nov 2013 21:05:29 +0100
>Subject: [PATCH] smbd: Fix bug 10284
>
>If we msg_read_send on a nonempty channel, we create one
>tevent_immediate. If we directly receive another message and from
>within the msg_read_send's tevent_req callback we immediately do
>another msg_read_send, we end up with two tevent_immediate events for
>msg_channel_trigger with just one incoming message. Test to follow.
>
>This patch simplifies msg_channel.c by removing the explicit immediate
>events. Instead, it relies on the implicit immediate event available
>via tevent_req_defer_callback. For messages received from tdb with
>a msg_read_send req pending, we directly finish that request without
>putting the message on the queue.
>
>Bug: https://bugzilla.samba.org/show_bug.cgi?id=10284
>Signed-off-by: Volker Lendecke <vl@samba.org>
>---
> source3/lib/msg_channel.c |  100 ++++++++++++++-------------------------------
> 1 file changed, 31 insertions(+), 69 deletions(-)
>
>diff --git a/source3/lib/msg_channel.c b/source3/lib/msg_channel.c
>index 537b162..8e23fd4 100644
>--- a/source3/lib/msg_channel.c
>+++ b/source3/lib/msg_channel.c
>@@ -41,9 +41,6 @@ static void msg_channel_init_got_ctdb(struct tevent_req *subreq);
> static void msg_channel_init_got_msg(struct messaging_context *msg,
> 			       void *priv, uint32_t msg_type,
> 			       struct server_id server_id, DATA_BLOB *data);
>-static void msg_channel_trigger(struct tevent_context *ev,
>-				struct tevent_immediate *im,
>-				void *priv);
> static int msg_channel_destructor(struct msg_channel *s);
> 
> struct tevent_req *msg_channel_init_send(TALLOC_CTX *mem_ctx,
>@@ -157,6 +154,12 @@ fail:
> 	return err;
> }
> 
>+struct msg_read_state {
>+	struct tevent_context *ev;
>+	struct msg_channel *channel;
>+	struct messaging_rec *rec;
>+};
>+
> static void msg_channel_init_got_msg(struct messaging_context *msg,
> 				     void *priv, uint32_t msg_type,
> 				     struct server_id server_id,
>@@ -167,7 +170,6 @@ static void msg_channel_init_got_msg(struct messaging_context *msg,
> 	struct messaging_rec *rec;
> 	struct messaging_rec **msgs;
> 	size_t num_msgs;
>-	struct tevent_immediate *im;
> 
> 	rec = talloc(s, struct messaging_rec);
> 	if (rec == NULL) {
>@@ -184,6 +186,19 @@ static void msg_channel_init_got_msg(struct messaging_context *msg,
> 	}
> 	rec->buf.length = data->length;
> 
>+	if (s->pending_req != NULL) {
>+		struct tevent_req *req = s->pending_req;
>+		struct msg_read_state *state = tevent_req_data(
>+			req, struct msg_read_state);
>+
>+		s->pending_req = NULL;
>+
>+		state->rec = talloc_move(state, &rec);
>+		tevent_req_defer_callback(req, s->ev);
>+		tevent_req_done(req);
>+		return;
>+	}
>+
> 	num_msgs = talloc_array_length(s->msgs);
> 	msgs = talloc_realloc(s, s->msgs, struct messaging_rec *, num_msgs+1);
> 	if (msgs == NULL) {
>@@ -192,28 +207,11 @@ static void msg_channel_init_got_msg(struct messaging_context *msg,
> 	s->msgs = msgs;
> 	s->msgs[num_msgs] = talloc_move(s->msgs, &rec);
> 
>-	if (s->pending_req == NULL) {
>-		return;
>-	}
>-
>-	im = tevent_create_immediate(s);
>-	if (im == NULL) {
>-		goto fail;
>-	}
>-	tevent_schedule_immediate(im, s->ev, msg_channel_trigger, s);
> 	return;
> fail:
> 	TALLOC_FREE(rec);
> }
> 
>-struct msg_read_state {
>-	struct tevent_context *ev;
>-	struct tevent_req *req;
>-	struct msg_channel *channel;
>-	struct messaging_rec *rec;
>-};
>-
>-static int msg_read_state_destructor(struct msg_read_state *s);
> static void msg_read_got_ctdb(struct tevent_req *subreq);
> 
> struct tevent_req *msg_read_send(TALLOC_CTX *mem_ctx,
>@@ -221,7 +219,6 @@ struct tevent_req *msg_read_send(TALLOC_CTX *mem_ctx,
> 				 struct msg_channel *channel)
> {
> 	struct tevent_req *req;
>-	struct tevent_immediate *im;
> 	struct msg_read_state *state;
> 	void *msg_tdb_event;
> 	size_t num_msgs;
>@@ -231,28 +228,28 @@ struct tevent_req *msg_read_send(TALLOC_CTX *mem_ctx,
> 		return NULL;
> 	}
> 	state->ev = ev;
>-	state->req = req;
> 	state->channel = channel;
> 
> 	if (channel->pending_req != NULL) {
> 		tevent_req_error(req, EBUSY);
> 		return tevent_req_post(req, ev);
> 	}
>-	channel->pending_req = req;
>-	channel->ev = ev;
>-	talloc_set_destructor(state, msg_read_state_destructor);
> 
> 	num_msgs = talloc_array_length(channel->msgs);
> 	if (num_msgs != 0) {
>-		im = tevent_create_immediate(channel->ev);
>-		if (tevent_req_nomem(im, req)) {
>-			return tevent_req_post(req, ev);
>-		}
>-		tevent_schedule_immediate(im, channel->ev, msg_channel_trigger,
>-					  channel);
>-		return req;
>+		state->rec = talloc_move(state, &channel->msgs[0]);
>+		memmove(channel->msgs, channel->msgs+1,
>+			sizeof(struct messaging_rec *) * (num_msgs-1));
>+		channel->msgs = talloc_realloc(
>+			channel, channel->msgs, struct messaging_rec *,
>+			num_msgs - 1);
>+		tevent_req_done(req);
>+		return tevent_req_post(req, ev);
> 	}
> 
>+	channel->pending_req = req;
>+	channel->ev = ev;
>+
> 	msg_tdb_event = messaging_tdb_event(state, channel->msg, ev);
> 	if (tevent_req_nomem(msg_tdb_event, req)) {
> 		return tevent_req_post(req, ev);
>@@ -271,42 +268,6 @@ struct tevent_req *msg_read_send(TALLOC_CTX *mem_ctx,
> 	return req;
> }
> 
>-static int msg_read_state_destructor(struct msg_read_state *s)
>-{
>-	assert(s->channel->pending_req == s->req);
>-	s->channel->pending_req = NULL;
>-	return 0;
>-}
>-
>-static void msg_channel_trigger(struct tevent_context *ev,
>-			       struct tevent_immediate *im,
>-			       void *priv)
>-{
>-	struct msg_channel *channel;
>-	struct tevent_req *req;
>-	struct msg_read_state *state;
>-	size_t num_msgs;
>-
>-	channel = talloc_get_type_abort(priv, struct msg_channel);
>-	req = channel->pending_req;
>-	state = tevent_req_data(req, struct msg_read_state);
>-
>-	talloc_set_destructor(state, NULL);
>-	msg_read_state_destructor(state);
>-
>-	num_msgs = talloc_array_length(channel->msgs);
>-	assert(num_msgs > 0);
>-
>-	state->rec = talloc_move(state, &channel->msgs[0]);
>-
>-	memmove(channel->msgs, channel->msgs+1,
>-		sizeof(struct messaging_rec *) * (num_msgs-1));
>-	channel->msgs = talloc_realloc(
>-		channel, channel->msgs, struct messaging_rec *, num_msgs - 1);
>-
>-	tevent_req_done(req);
>-}
>-
> static void msg_read_got_ctdb(struct tevent_req *subreq)
> {
> 	struct tevent_req *req = tevent_req_callback_data(
>@@ -368,5 +329,6 @@ int msg_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
> 		return err;
> 	}
> 	*prec = talloc_move(mem_ctx, &state->rec);
>+	tevent_req_received(req);
> 	return 0;
> }
>-- 
>1.7.9.5
>

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