[04/12] tools/xenstore: use accounting buffering for node accounting

Commit Message

Jürgen Groß Nov. 1, 2022, 4:04 p.m. UTC

Add the node accounting to the accounting information buffering in
order to avoid having to undo it in case of failure.

Signed-off-by: Juergen Gross <[e-mail]>
---
 tools/xenstore/xenstored_core.c   | 21 ++-------------------
 tools/xenstore/xenstored_domain.h |  4 ++--
 2 files changed, 4 insertions(+), 21 deletions(-)

Patch

diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
index d437149622..7bf56b4d38 100644
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -1442,7 +1442,6 @@  static void destroy_node_rm(struct connection *conn, struct node *node)
 static int destroy_node(struct connection *conn, struct node *node)
 {
 	destroy_node_rm(conn, node);
-	domain_nbentry_dec(conn, node->perms.p[0].id);
 
 	/*
 	 * It is not possible to easily revert the changes in a transaction.
@@ -1788,27 +1787,11 @@  static int do_set_perms(const void *ctx, struct connection *conn,
 	old_perms = node->perms;
 	domain_nbentry_dec(conn, node->perms.p[0].id);
 	node->perms = perms;
-	if (domain_nbentry_inc(conn, node->perms.p[0].id)) {
-		node->perms = old_perms;
-		/*
-		 * This should never fail because we had a reference on the
-		 * domain before and Xenstored is single-threaded.
-		 */
-		domain_nbentry_inc(conn, node->perms.p[0].id);
+	if (domain_nbentry_inc(conn, node->perms.p[0].id))
 		return ENOMEM;
-	}
 
-	if (write_node(conn, node, false)) {
-		int saved_errno = errno;
-
-		domain_nbentry_dec(conn, node->perms.p[0].id);
-		node->perms = old_perms;
-		/* No failure possible as above. */
-		domain_nbentry_inc(conn, node->perms.p[0].id);
-
-		errno = saved_errno;
+	if (write_node(conn, node, false))
 		return errno;
-	}
 
 	fire_watches(conn, ctx, name, node, false, &old_perms);
 	send_ack(conn, XS_SET_PERMS);
diff --git a/tools/xenstore/xenstored_domain.h b/tools/xenstore/xenstored_domain.h
index 9959b2f2e4..ead3893fc1 100644
--- a/tools/xenstore/xenstored_domain.h
+++ b/tools/xenstore/xenstored_domain.h
@@ -20,9 +20,9 @@ 
 #define _XENSTORED_DOMAIN_H
 
 enum {
+	ACC_NODES,
 	ACC_REQ_N,       /* Number of elements per request and domain. */
-	ACC_NODES = ACC_REQ_N,
-	ACC_TR_N,        /* Number of elements per transaction and domain. */
+	ACC_TR_N = ACC_REQ_N, /* Number of elements per transaction and domain. */
 	ACC_N = ACC_TR_N /* Number of elements per domain. */
 };