patch-0001-xenstore-modify-add_change_node-parameter-types.patch

From fe3566c92073e9e655a64f8894957f6003b05f37 Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@suse.com>
Date: Mon, 5 Dec 2016 08:48:42 +0100
Subject: [PATCH 01/25] xenstore: modify add_change_node() parameter types

In order to prepare adding a generation count to each node modify
add_change_node() to take the connection pointer and a node pointer
instead of the transaction pointer and node name as parameters. This
requires moving the call of add_change_node() from do_rm() to
delete_node_single().

While at it correct the comment for the prototype: there is no
longjmp() involved.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
---
 tools/xenstore/xenstored_core.c        | 22 +++++++++++++---------
 tools/xenstore/xenstored_transaction.c | 11 +++++++----
 tools/xenstore/xenstored_transaction.h |  4 ++--
 3 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
index dc9a26f1dcc6..5d8afd6f3044 100644
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -827,7 +827,8 @@ static void do_read(struct connection *conn, struct buffered_data *in)
 	send_reply(conn, XS_READ, node->data, node->datalen);
 }
 
-static void delete_node_single(struct connection *conn, struct node *node)
+static void delete_node_single(struct connection *conn, struct node *node,
+			       bool changed)
 {
 	TDB_DATA key;
 
@@ -839,6 +840,9 @@ static void delete_node_single(struct connection *conn, struct node *node)
 		return;
 	}
 
+	if (changed)
+		add_change_node(conn, node, true);
+
 	domain_entry_dec(conn, node);
 }
 
@@ -977,7 +981,7 @@ static void do_write(struct connection *conn, struct buffered_data *in)
 		}
 	}
 
-	add_change_node(conn->transaction, name, false);
+	add_change_node(conn, node, false);
 	wrl_apply_debit_direct(conn);
 	fire_watches(conn, in, name, false);
 	send_ack(conn, XS_WRITE);
@@ -1009,21 +1013,22 @@ static void do_mkdir(struct connection *conn, struct buffered_data *in)
 			send_error(conn, errno);
 			return;
 		}
-		add_change_node(conn->transaction, name, false);
+		add_change_node(conn, node, false);
 		wrl_apply_debit_direct(conn);
 		fire_watches(conn, in, name, false);
 	}
 	send_ack(conn, XS_MKDIR);
 }
 
-static void delete_node(struct connection *conn, struct node *node)
+static void delete_node(struct connection *conn, struct node *node,
+			bool changed)
 {
 	unsigned int i;
 
 	/* Delete self, then delete children.  If we crash, then the worst
 	   that can happen is the children will continue to take up space, but
 	   will otherwise be unreachable. */
-	delete_node_single(conn, node);
+	delete_node_single(conn, node, changed);
 
 	/* Delete children, too. */
 	for (i = 0; i < node->childlen; i += strlen(node->children+i) + 1) {
@@ -1033,7 +1038,7 @@ static void delete_node(struct connection *conn, struct node *node)
 				  talloc_asprintf(node, "%s/%s", node->name,
 						  node->children + i));
 		if (child) {
-			delete_node(conn, child);
+			delete_node(conn, child, false);
 		}
 		else {
 			trace("delete_node: No child '%s/%s' found!\n",
@@ -1092,7 +1097,7 @@ static int _rm(struct connection *conn, struct node *node, const char *name)
 		return 0;
 	}
 
-	delete_node(conn, node);
+	delete_node(conn, node, true);
 	return 1;
 }
 
@@ -1136,7 +1141,6 @@ static void do_rm(struct connection *conn, struct buffered_data *in)
 	}
 
 	if (_rm(conn, node, name)) {
-		add_change_node(conn->transaction, name, true);
 		wrl_apply_debit_direct(conn);
 		fire_watches(conn, in, name, true);
 		send_ack(conn, XS_RM);
@@ -1213,7 +1217,7 @@ static void do_set_perms(struct connection *conn, struct buffered_data *in)
 		return;
 	}
 
-	add_change_node(conn->transaction, name, false);
+	add_change_node(conn, node, false);
 	wrl_apply_debit_direct(conn);
 	fire_watches(conn, in, name, false);
 	send_ack(conn, XS_SET_PERMS);
diff --git a/tools/xenstore/xenstored_transaction.c b/tools/xenstore/xenstored_transaction.c
index 5059a11b6b0b..ee4bd3e68624 100644
--- a/tools/xenstore/xenstored_transaction.c
+++ b/tools/xenstore/xenstored_transaction.c
@@ -92,18 +92,21 @@ TDB_CONTEXT *tdb_transaction_context(struct transaction *trans)
 
 /* Callers get a change node (which can fail) and only commit after they've
  * finished.  This way they don't have to unwind eg. a write. */
-void add_change_node(struct transaction *trans, const char *node, bool recurse)
+void add_change_node(struct connection *conn, struct node *node, bool recurse)
 {
 	struct changed_node *i;
+	struct transaction *trans;
 
-	if (!trans) {
+	if (!conn || !conn->transaction) {
 		/* They're changing the global database. */
 		generation++;
 		return;
 	}
 
+	trans = conn->transaction;
+
 	list_for_each_entry(i, &trans->changes, list) {
-		if (streq(i->node, node)) {
+		if (streq(i->node, node->name)) {
 			if (recurse)
 				i->recurse = recurse;
 			return;
@@ -111,7 +114,7 @@ void add_change_node(struct transaction *trans, const char *node, bool recurse)
 	}
 
 	i = talloc(trans, struct changed_node);
-	i->node = talloc_strdup(i, node);
+	i->node = talloc_strdup(i, node->name);
 	i->recurse = recurse;
 	list_add_tail(&i->list, &trans->changes);
 }
diff --git a/tools/xenstore/xenstored_transaction.h b/tools/xenstore/xenstored_transaction.h
index 0c868ee504ee..7f0a78179235 100644
--- a/tools/xenstore/xenstored_transaction.h
+++ b/tools/xenstore/xenstored_transaction.h
@@ -30,8 +30,8 @@ struct transaction *transaction_lookup(struct connection *conn, uint32_t id);
 void transaction_entry_inc(struct transaction *trans, unsigned int domid);
 void transaction_entry_dec(struct transaction *trans, unsigned int domid);
 
-/* This node was changed: can fail and longjmp. */
-void add_change_node(struct transaction *trans, const char *node,
+/* This node was changed. */
+void add_change_node(struct connection *conn, struct node *node,
                      bool recurse);
 
 /* Return tdb context to use for this connection. */
-- 
2.25.4