patch-0002-xenstore-call-add_change_node-directly-when-writing-.patch

From bb39decb3d9842ee99d888675c6ed5ca48639c02 Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@suse.com>
Date: Mon, 5 Dec 2016 08:48:43 +0100
Subject: [PATCH 02/25] xenstore: call add_change_node() directly when writing
 node

Instead of calling add_change_node() at places where write_node() is
called, do that inside write_node().

Note that there is one case where add_change_node() is called now when
a later failure will prohibit the changed node to be written: in case
of a write_node failing due to an error in tdb_store(). As the only
visible change of behavior is a stale event fired for the node, while
the failing tdb_store() signals a corrupted xenstore database, the
stale event will be the least problem of this case.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
---
 tools/xenstore/xenstored_core.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
index 5d8afd6f3044..518a55805e7f 100644
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -461,7 +461,7 @@ static struct node *read_node(struct connection *conn, const void *ctx,
 	return node;
 }
 
-static bool write_node(struct connection *conn, const struct node *node)
+static bool write_node(struct connection *conn, struct node *node)
 {
 	/*
 	 * conn will be null when this is called from manual_node.
@@ -481,6 +481,8 @@ static bool write_node(struct connection *conn, const struct node *node)
 	if (domain_is_unprivileged(conn) && data.dsize >= quota_max_entry_size)
 		goto error;
 
+	add_change_node(conn, node, false);
+
 	data.dptr = talloc_size(node, data.dsize);
 	((uint32_t *)data.dptr)[0] = node->num_perms;
 	((uint32_t *)data.dptr)[1] = node->datalen;
@@ -981,7 +983,6 @@ static void do_write(struct connection *conn, struct buffered_data *in)
 		}
 	}
 
-	add_change_node(conn, node, false);
 	wrl_apply_debit_direct(conn);
 	fire_watches(conn, in, name, false);
 	send_ack(conn, XS_WRITE);
@@ -1013,7 +1014,6 @@ static void do_mkdir(struct connection *conn, struct buffered_data *in)
 			send_error(conn, errno);
 			return;
 		}
-		add_change_node(conn, node, false);
 		wrl_apply_debit_direct(conn);
 		fire_watches(conn, in, name, false);
 	}
@@ -1217,7 +1217,6 @@ static void do_set_perms(struct connection *conn, struct buffered_data *in)
 		return;
 	}
 
-	add_change_node(conn, node, false);
 	wrl_apply_debit_direct(conn);
 	fire_watches(conn, in, name, false);
 	send_ack(conn, XS_SET_PERMS);
-- 
2.25.4