Fix xenstore entry accounting

xenstored is incorrectly accounting domain nodes when transactions
fail. Store pending count changes in the transaction structure, and
apply at transaction completion, instead of directly applying the
changes.

Signed-off-by: Max Zhen <max.zhen@sun.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/tools/xenstore/xenstored_transaction.c b/tools/xenstore/xenstored_transaction.c
index cf10ecc348..0270301396 100644
--- a/tools/xenstore/xenstored_transaction.c
+++ b/tools/xenstore/xenstored_transaction.c
@@ -32,6 +32,7 @@
 #include "list.h"
 #include "xenstored_transaction.h"
 #include "xenstored_watch.h"
+#include "xenstored_domain.h"
 #include "xs_lib.h"
 #include "utils.h"
 #include "xenstored_test.h"
@@ -48,6 +49,18 @@ struct changed_node
 	bool recurse;
 };
 
+struct changed_domain
+{
+	/* List of all changed domains in the context of this transaction. */
+	struct list_head list;
+
+	/* Identifier of the changed domain. */
+	unsigned int domid;
+
+	/* Amount by which this domain's nbentry field has changed. */
+	int nbentry;
+};
+
 struct transaction
 {
 	/* List of all transactions active on this connection. */
@@ -65,6 +78,9 @@ struct transaction
 
 	/* List of changed nodes. */
 	struct list_head changes;
+
+	/* List of changed domains - to record the changed domain entry number */
+	struct list_head changed_domains;
 };
 
 extern int quota_max_transaction;
@@ -142,6 +158,7 @@ void do_transaction_start(struct connection *conn, struct buffered_data *in)
 	/* Attach transaction to input for autofree until it's complete */
 	trans = talloc(in, struct transaction);
 	INIT_LIST_HEAD(&trans->changes);
+	INIT_LIST_HEAD(&trans->changed_domains);
 	trans->generation = generation;
 	trans->tdb_name = talloc_asprintf(trans, "%s.%p",
 					  xs_daemon_tdb(), trans);
@@ -172,6 +189,7 @@ void do_transaction_start(struct connection *conn, struct buffered_data *in)
 void do_transaction_end(struct connection *conn, const char *arg)
 {
 	struct changed_node *i;
+	struct changed_domain *d;
 	struct transaction *trans;
 
 	if (!arg || (!streq(arg, "T") && !streq(arg, "F"))) {
@@ -204,6 +222,10 @@ void do_transaction_end(struct connection *conn, const char *arg)
 		/* Don't close this: we won! */
 		trans->tdb = NULL;
 
+		/* fix domain entry for each changed domain */
+		list_for_each_entry(d, &trans->changed_domains, list)
+			domain_entry_fix(d->domid, d->nbentry);
+
 		/* Fire off the watches for everything that changed. */
 		list_for_each_entry(i, &trans->changes, list)
 			fire_watches(conn, i->node, i->recurse);
@@ -212,6 +234,38 @@ void do_transaction_end(struct connection *conn, const char *arg)
 	send_ack(conn, XS_TRANSACTION_END);
 }
 
+void transaction_entry_inc(struct transaction *trans, unsigned int domid)
+{
+	struct changed_domain *d;
+
+	list_for_each_entry(d, &trans->changed_domains, list)
+		if (d->domid == domid) {
+			d->nbentry++;
+			return;
+		}
+
+	d = talloc(trans, struct changed_domain);
+	d->domid = domid;
+	d->nbentry = 1;
+	list_add_tail(&d->list, &trans->changed_domains);
+}
+
+void transaction_entry_dec(struct transaction *trans, unsigned int domid)
+{
+	struct changed_domain *d;
+
+	list_for_each_entry(d, &trans->changed_domains, list)
+		if (d->domid == domid) {
+			d->nbentry--;
+			return;
+		}
+
+	d = talloc(trans, struct changed_domain);
+	d->domid = domid;
+	d->nbentry = -1;
+	list_add_tail(&d->list, &trans->changed_domains);
+}
+
 void conn_delete_all_transactions(struct connection *conn)
 {
 	struct transaction *trans;