@@ -25,6 +25,8 @@ typedef struct XsNode {
Object obj;
GByteArray *content;
GHashTable *children;
+ bool deleted_in_tx;
+ bool modified_in_tx;
#ifdef XS_NODE_UNIT_TEST
gchar *name; /* debug only */
#endif
@@ -119,6 +121,12 @@ static XsNode *xs_node_copy(XsNode *old)
{
XsNode *n = xs_node_new();
+#ifdef XS_NODE_UNIT_TEST
+ if (n->name) {
+ n->name = g_strdup(old->name);
+ }
+#endif
+
if (old->children) {
n->children = g_hash_table_new_full(g_str_hash, g_str_equal, g_free,
object_unref);
@@ -159,6 +167,7 @@ struct walk_op {
GList *watches;
unsigned int dom_id;
+ unsigned int tx_id;
/*
* This is maintained on the way *down* the walk to indicate
@@ -174,6 +183,9 @@ struct walk_op {
bool mutating;
bool create_dirs;
bool in_transaction;
+
+ /* Tracking during recursion so we know which is first. */
+ bool deleted_in_tx;
};
static void fire_watches(struct walk_op *op, bool parents)
@@ -218,6 +230,9 @@ static int xs_node_add_content(XsNode **n, struct walk_op *op)
g_byte_array_unref((*n)->content);
}
(*n)->content = g_byte_array_ref(op->op_opaque);
+ if (op->tx_id != XBT_NULL) {
+ (*n)->modified_in_tx = true;
+ }
return 0;
}
@@ -273,10 +288,49 @@ static int node_rm_recurse(gpointer key, gpointer value, gpointer user_data)
return this_inplace;
}
+static XsNode *xs_node_copy_deleted(XsNode *old);
+static void copy_deleted_recurse(gpointer key, gpointer value,
+ gpointer user_data)
+{
+ XsNode *n = xs_node_copy_deleted(value);
+ g_hash_table_insert(user_data, g_strdup(key), n);
+}
+
+static XsNode *xs_node_copy_deleted(XsNode *old)
+{
+ XsNode *n = xs_node_new();
+
+#ifdef XS_NODE_UNIT_TEST
+ if (old->name) {
+ n->name = g_strdup(old->name);
+ }
+#endif
+
+ if (old->children) {
+ n->children = g_hash_table_new_full(g_str_hash, g_str_equal, g_free,
+ object_unref);
+ g_hash_table_foreach(old->children, copy_deleted_recurse, n->children);
+ }
+ n->deleted_in_tx = true;
+ /* If it gets resurrected we only fire a watch if it lost its content */
+ if (old->content) {
+ n->modified_in_tx = true;
+ }
+ return n;
+}
+
static int xs_node_rm(XsNode **n, struct walk_op *op)
{
bool this_inplace = op->inplace;
+ if (op->tx_id != XBT_NULL) {
+ /* It's not trivial to do inplace handling for this one */
+ XsNode *old = *n;
+ *n = xs_node_copy_deleted(old);
+ xs_node_unref(old);
+ return 0;
+ }
+
/* Fire watches for any node in the subtree which gets deleted. */
if ((*n)->children) {
g_hash_table_foreach_remove((*n)->children, node_rm_recurse, op);
@@ -347,6 +401,10 @@ static int xs_node_walk(XsNode **n, struct walk_op *op)
}
if (child) {
+ if (child->deleted_in_tx) {
+ assert(child->obj.ref == 1);
+ child->deleted_in_tx = false;
+ }
xs_node_ref(child);
/*
* Now we own it too. But if we can modify inplace, that's going to
@@ -479,6 +537,7 @@ static int init_walk_op(XenstoreImplState *s, struct walk_op *op,
op->create_dirs = false;
op->in_transaction = false;
op->dom_id = dom_id;
+ op->tx_id = tx_id;
op->s = s;
if (tx_id == XBT_NULL) {
@@ -580,8 +639,69 @@ int xs_impl_transaction_start(XenstoreImplState *s, unsigned int dom_id,
return 0;
}
+static gboolean tx_commit_walk(gpointer key, gpointer value,
+ gpointer user_data)
+{
+ struct walk_op *op = user_data;
+ int path_len = strlen(op->path);
+ int key_len = strlen(key);
+ bool fire_parents = true;
+ XsWatch *watch;
+ XsNode *n = value;
+
+ if (n->obj.ref != 1) {
+ return false;
+ }
+
+ if (n->deleted_in_tx) {
+ /*
+ * We first watches on our parents if we are the *first* node
+ * to be deleted (the topmost one). This matches the behaviour
+ * when deleting in the live tree.
+ */
+ fire_parents = !op->deleted_in_tx;
+
+ /* Only used on the way down so no need to clear it later */
+ op->deleted_in_tx = true;
+ }
+
+ assert(key_len + path_len + 2 <= sizeof(op->path));
+ op->path[path_len] = '/';
+ memcpy(op->path + path_len + 1, key, key_len + 1);
+
+ watch = g_hash_table_lookup(op->s->watches, op->path);
+ if (watch) {
+ op->watches = g_list_append(op->watches, watch);
+ }
+
+ if (n->children) {
+ g_hash_table_foreach_remove(n->children, tx_commit_walk, op);
+ }
+
+ if (watch) {
+ op->watches = g_list_remove(op->watches, watch);
+ }
+
+ /*
+ * Don't fire watches if this node was only copied because a
+ * descendent was changed. The modifieD_in_tx flag indicates the
+ * ones which were really changed.
+ */
+ if (n->modified_in_tx || n->deleted_in_tx) {
+ fire_watches(op, fire_parents);
+ n->modified_in_tx = false;
+ }
+ op->path[path_len] = '\0';
+
+ /* Deleted nodes really do get expunged when we commit */
+ return n->deleted_in_tx;
+}
+
static int transaction_commit(XenstoreImplState *s, XsTransaction *tx)
{
+ struct walk_op op;
+ XsNode **n;
+
if (s->root_tx != tx->base_tx) {
return EAGAIN;
}
@@ -590,10 +710,18 @@ static int transaction_commit(XenstoreImplState *s, XsTransaction *tx)
tx->root = NULL;
s->root_tx = tx->tx_id;
+ init_walk_op(s, &op, XBT_NULL, tx->dom_id, "/", &n);
+ op.deleted_in_tx = false;
+ op.mutating = true;
+
/*
- * XX: Walk the new root and fire watches on any node which has a
+ * Walk the new root and fire watches on any node which has a
* refcount of one (which is therefore unique to this transaction).
*/
+ if (s->root->children) {
+ g_hash_table_foreach_remove(s->root->children, tx_commit_walk, &op);
+ }
+
return 0;
}
@@ -292,14 +292,21 @@ static void do_test_xs_node_tx(bool fail, bool commit)
g_assert(!err);
g_assert(!watches->len);
- /* The transaction should fail */
+ /* Attempt to commit the transaction */
err = xs_impl_transaction_end(s, DOMID_GUEST, tx_id, commit);
if (commit && fail) {
g_assert(err == EAGAIN);
} else {
g_assert(!err);
}
- g_assert(!watches->len);
+
+ if (commit && !fail) {
+ g_assert(!strcmp(watches->str,
+ "some/relative/pathwatch"));
+ g_string_truncate(watches, 0);
+ } else {
+ g_assert(!watches->len);
+ }
err = xs_impl_unwatch(s, DOMID_GUEST, "some", "watch",
watch_cb, watches);
@@ -337,6 +344,135 @@ static void test_xs_node_tx_succeed(void)
do_test_xs_node_tx(false, true);
}
+static void test_xs_node_tx_rm(void)
+{
+ XenstoreImplState *s = setup();
+ GString *watches = g_string_new(NULL);
+ GByteArray *data = g_byte_array_new();
+ unsigned int tx_id = XBT_NULL;
+ int err;
+
+ g_assert(s);
+
+ /* Set a watch */
+ err = xs_impl_watch(s, DOMID_GUEST, "some", "watch",
+ watch_cb, watches);
+ g_assert(!err);
+ g_assert(watches->len == strlen("somewatch"));
+ g_assert(!strcmp(watches->str, "somewatch"));
+ g_string_truncate(watches, 0);
+
+ /* Write something */
+ err = write_str(s, DOMID_GUEST, XBT_NULL, "some/deep/dark/relative/path",
+ "something");
+ g_assert(!err);
+ g_assert(!strcmp(watches->str,
+ "some/deep/dark/relative/pathwatch"));
+ g_string_truncate(watches, 0);
+
+ /* Create a transaction */
+ err = xs_impl_transaction_start(s, DOMID_GUEST, &tx_id);
+ g_assert(!err);
+
+ /* Delete the tree in the transaction */
+ err = xs_impl_rm(s, DOMID_GUEST, tx_id, "some/deep/dark");
+ g_assert(!err);
+ g_assert(!watches->len);
+
+ err = xs_impl_read(s, DOMID_GUEST, XBT_NULL, "some/deep/dark/relative/path",
+ data);
+ g_assert(!err);
+ g_assert(data->len == strlen("something"));
+ g_assert(!memcmp(data->data, "something", data->len));
+ g_byte_array_set_size(data, 0);
+
+ /* Commit the transaction */
+ err = xs_impl_transaction_end(s, DOMID_GUEST, tx_id, true);
+ g_assert(!err);
+
+ g_assert(!strcmp(watches->str, "some/deep/darkwatch"));
+ g_string_truncate(watches, 0);
+
+ /* Now the node is gone */
+ err = xs_impl_read(s, DOMID_GUEST, XBT_NULL, "some/deep/dark/relative/path",
+ data);
+ g_assert(err == ENOENT);
+ g_byte_array_unref(data);
+
+ err = xs_impl_unwatch(s, DOMID_GUEST, "some", "watch",
+ watch_cb, watches);
+ g_assert(!err);
+
+ g_string_free(watches, true);
+ xs_impl_delete(s);
+}
+
+static void test_xs_node_tx_resurrect(void)
+{
+ XenstoreImplState *s = setup();
+ GString *watches = g_string_new(NULL);
+ GByteArray *data = g_byte_array_new();
+ unsigned int tx_id = XBT_NULL;
+ int err;
+
+ g_assert(s);
+
+ /* Write something */
+ err = write_str(s, DOMID_GUEST, XBT_NULL, "some/deep/dark/relative/path",
+ "something");
+ g_assert(!err);
+
+ /* This node will be wiped and resurrected */
+ err = write_str(s, DOMID_GUEST, XBT_NULL, "some/deep/dark",
+ "foo");
+ g_assert(!err);
+
+ /* Set a watch */
+ err = xs_impl_watch(s, DOMID_GUEST, "some", "watch",
+ watch_cb, watches);
+ g_assert(!err);
+ g_assert(watches->len == strlen("somewatch"));
+ g_assert(!strcmp(watches->str, "somewatch"));
+ g_string_truncate(watches, 0);
+
+ /* Create a transaction */
+ err = xs_impl_transaction_start(s, DOMID_GUEST, &tx_id);
+ g_assert(!err);
+
+ /* Delete the tree in the transaction */
+ err = xs_impl_rm(s, DOMID_GUEST, tx_id, "some/deep");
+ g_assert(!err);
+ g_assert(!watches->len);
+
+ /* Resurrect part of it */
+ err = write_str(s, DOMID_GUEST, tx_id, "some/deep/dark/different/path",
+ "something");
+ g_assert(!err);
+
+ /* Commit the transaction */
+ err = xs_impl_transaction_end(s, DOMID_GUEST, tx_id, true);
+ g_assert(!err);
+
+ g_assert(!strcmp(watches->str,
+ "some/deep/dark/different/pathwatch" /* lost data */
+ "some/deep/dark/relativewatch" /* topmost deleted */
+ "some/deep/darkwatch" /* lost data */));
+ g_string_truncate(watches, 0);
+
+ /* Now the node is gone */
+ err = xs_impl_read(s, DOMID_GUEST, XBT_NULL, "some/deep/dark/relative/path",
+ data);
+ g_assert(err == ENOENT);
+ g_byte_array_unref(data);
+
+ err = xs_impl_unwatch(s, DOMID_GUEST, "some", "watch",
+ watch_cb, watches);
+ g_assert(!err);
+
+ g_string_free(watches, true);
+ xs_impl_delete(s);
+}
+
int main(int argc, char **argv)
{
g_test_init(&argc, &argv, NULL);
@@ -346,6 +482,8 @@ int main(int argc, char **argv)
g_test_add_func("/xs_node/tx_abort", test_xs_node_tx_abort);
g_test_add_func("/xs_node/tx_fail", test_xs_node_tx_fail);
g_test_add_func("/xs_node/tx_succeed", test_xs_node_tx_succeed);
+ g_test_add_func("/xs_node/tx_rm", test_xs_node_tx_rm);
+ g_test_add_func("/xs_node/tx_resurrect", test_xs_node_tx_resurrect);
return g_test_run();
}