Page MenuHomeClusterLabs Projects
Files F4638885

No OneTemporary
Actions

View Options

diff --git a/daemons/attrd/attrd_sync.c b/daemons/attrd/attrd_sync.c
index c9b47849b9..9d07796172 100644
--- a/daemons/attrd/attrd_sync.c
+++ b/daemons/attrd/attrd_sync.c
@@ -1,522 +1,571 @@
/*
* Copyright 2022 the Pacemaker project contributors
*
* The version control history for this file may have further details.
*
* This source code is licensed under the GNU General Public License version 2
* or later (GPLv2+) WITHOUT ANY WARRANTY.
*/
#include <crm_internal.h>
#include <crm/msg_xml.h>
#include <crm/common/attrd_internal.h>
#include "pacemaker-attrd.h"
/* A hash table storing clients that are waiting on a sync point to be reached.
* The key is waitlist_client - just a plain int. The obvious key would be
* the IPC client's ID, but this is not guaranteed to be unique. A single client
* could be waiting on a sync point for multiple attributes at the same time.
*
* It is not expected that this hash table will ever be especially large.
*/
static GHashTable *waitlist = NULL;
static int waitlist_client = 0;
struct waitlist_node {
/* What kind of sync point does this node describe? */
enum attrd_sync_point sync_point;
/* Information required to construct and send a reply to the client. */
char *client_id;
uint32_t ipc_id;
uint32_t flags;
};
/* A hash table storing information on in-progress IPC requests that are awaiting
* confirmations. These requests are currently being processed by peer attrds and
* we are waiting to receive confirmation messages from each peer indicating that
* processing is complete.
*
* Multiple requests could be waiting on confirmations at the same time.
*
* The key is the unique callid for the IPC request, and the value is a
* confirmation_action struct.
*/
static GHashTable *expected_confirmations = NULL;
/*!
* \internal
* \brief A structure describing a single IPC request that is awaiting confirmations
*/
struct confirmation_action {
/*!
* \brief A list of peer attrds that we are waiting to receive confirmation
* messages from
*
* This list is dynamic - as confirmations arrive from peer attrds, they will
* be removed from this list. When the list is empty, all peers have processed
* the request and the associated confirmation action will be taken.
*/
GList *respondents;
+ /*!
+ * \brief A timer that will be used to remove the client should it time out
+ * before receiving all confirmations
+ */
+ mainloop_timer_t *timer;
+
/*!
* \brief A function to run when all confirmations have been received
*/
attrd_confirmation_action_fn fn;
/*!
* \brief Information required to construct and send a reply to the client
*/
char *client_id;
uint32_t ipc_id;
uint32_t flags;
/*!
* \brief The XML request containing the callid associated with this action
*/
void *xml;
};
static void
next_key(void)
{
do {
waitlist_client++;
if (waitlist_client < 0) {
waitlist_client = 1;
}
} while (g_hash_table_contains(waitlist, GINT_TO_POINTER(waitlist_client)));
}
static void
free_waitlist_node(gpointer data)
{
struct waitlist_node *wl = (struct waitlist_node *) data;
free(wl->client_id);
free(wl);
}
static const char *
sync_point_str(enum attrd_sync_point sync_point)
{
if (sync_point == attrd_sync_point_local) {
return PCMK__VALUE_LOCAL;
} else if (sync_point == attrd_sync_point_cluster) {
return PCMK__VALUE_CLUSTER;
} else {
return "unknown";
}
}
/*!
* \internal
* \brief Add a client to the attrd waitlist
*
* Typically, a client receives an ACK for its XML IPC request immediately. However,
* some clients want to wait until their request has been processed and taken effect.
* This is called a sync point. Any client placed on this waitlist will have its
* ACK message delayed until either its requested sync point is hit, or until it
* times out.
*
* The XML IPC request must specify the type of sync point it wants to wait for.
*
* \param[in,out] request The request describing the client to place on the waitlist.
*/
void
attrd_add_client_to_waitlist(pcmk__request_t *request)
{
const char *sync_point = attrd_request_sync_point(request->xml);
struct waitlist_node *wl = NULL;
if (sync_point == NULL) {
return;
}
if (waitlist == NULL) {
waitlist = pcmk__intkey_table(free_waitlist_node);
}
wl = calloc(sizeof(struct waitlist_node), 1);
CRM_ASSERT(wl != NULL);
wl->client_id = strdup(request->ipc_client->id);
CRM_ASSERT(wl->client_id);
if (pcmk__str_eq(sync_point, PCMK__VALUE_LOCAL, pcmk__str_none)) {
wl->sync_point = attrd_sync_point_local;
} else if (pcmk__str_eq(sync_point, PCMK__VALUE_CLUSTER, pcmk__str_none)) {
wl->sync_point = attrd_sync_point_cluster;
} else {
free_waitlist_node(wl);
return;
}
wl->ipc_id = request->ipc_id;
wl->flags = request->flags;
next_key();
pcmk__intkey_table_insert(waitlist, waitlist_client, wl);
crm_trace("Added client %s to waitlist for %s sync point",
wl->client_id, sync_point_str(wl->sync_point));
crm_trace("%d clients now on waitlist", g_hash_table_size(waitlist));
/* And then add the key to the request XML so we can uniquely identify
* it when it comes time to issue the ACK.
*/
crm_xml_add_int(request->xml, XML_LRM_ATTR_CALLID, waitlist_client);
}
/*!
* \internal
* \brief Free all memory associated with the waitlist. This is most typically
* used when attrd shuts down.
*/
void
attrd_free_waitlist(void)
{
if (waitlist == NULL) {
return;
}
g_hash_table_destroy(waitlist);
waitlist = NULL;
}
/*!
* \internal
* \brief Unconditionally remove a client from the waitlist, such as when the client
* node disconnects from the cluster
*
* \param[in] client The client to remove
*/
void
attrd_remove_client_from_waitlist(pcmk__client_t *client)
{
GHashTableIter iter;
gpointer value;
if (waitlist == NULL) {
return;
}
g_hash_table_iter_init(&iter, waitlist);
while (g_hash_table_iter_next(&iter, NULL, &value)) {
struct waitlist_node *wl = (struct waitlist_node *) value;
if (pcmk__str_eq(wl->client_id, client->id, pcmk__str_none)) {
g_hash_table_iter_remove(&iter);
crm_trace("%d clients now on waitlist", g_hash_table_size(waitlist));
}
}
}
/*!
* \internal
* \brief Send an IPC ACK message to all awaiting clients
*
* This function will search the waitlist for all clients that are currently awaiting
* an ACK indicating their attrd operation is complete. Only those clients with a
* matching sync point type and callid from their original XML IPC request will be
* ACKed. Once they have received an ACK, they will be removed from the waitlist.
*
* \param[in] sync_point What kind of sync point have we hit?
* \param[in] xml The original XML IPC request.
*/
void
attrd_ack_waitlist_clients(enum attrd_sync_point sync_point, const xmlNode *xml)
{
int callid;
gpointer value;
if (waitlist == NULL) {
return;
}
if (crm_element_value_int(xml, XML_LRM_ATTR_CALLID, &callid) == -1) {
crm_warn("Could not get callid from request XML");
return;
}
value = pcmk__intkey_table_lookup(waitlist, callid);
if (value != NULL) {
struct waitlist_node *wl = (struct waitlist_node *) value;
pcmk__client_t *client = NULL;
if (wl->sync_point != sync_point) {
return;
}
crm_trace("Alerting client %s for reached %s sync point",
wl->client_id, sync_point_str(wl->sync_point));
client = pcmk__find_client_by_id(wl->client_id);
if (client == NULL) {
return;
}
attrd_send_ack(client, wl->ipc_id, wl->flags | crm_ipc_client_response);
/* And then remove the client so it doesn't get alerted again. */
pcmk__intkey_table_remove(waitlist, callid);
crm_trace("%d clients now on waitlist", g_hash_table_size(waitlist));
}
}
/*!
* \internal
* \brief Action to take when a cluster sync point is hit for a
* PCMK__ATTRD_CMD_UPDATE* message.
*
* \param[in] xml The request that should be passed along to
* attrd_ack_waitlist_clients. This should be the original
* IPC request containing the callid for this update message.
*/
int
attrd_cluster_sync_point_update(xmlNode *xml)
{
crm_trace("Hit cluster sync point for attribute update");
attrd_ack_waitlist_clients(attrd_sync_point_cluster, xml);
return pcmk_rc_ok;
}
/*!
* \internal
* \brief Return the sync point attribute for an IPC request
*
* This function will check both the top-level element of \p xml for a sync
* point attribute, as well as all of its \p op children, if any. The latter
* is useful for newer versions of attrd that can put multiple IPC requests
* into a single message.
*
* \param[in] xml An XML IPC request
*
* \note It is assumed that if one child element has a sync point attribute,
* all will have a sync point attribute and they will all be the same
* sync point. No other configuration is supported.
*
* \return The sync point attribute of \p xml, or NULL if none.
*/
const char *
attrd_request_sync_point(xmlNode *xml)
{
if (xml_has_children(xml)) {
xmlNode *child = pcmk__xe_match(xml, XML_ATTR_OP, PCMK__XA_ATTR_SYNC_POINT, NULL);
if (child) {
return crm_element_value(child, PCMK__XA_ATTR_SYNC_POINT);
} else {
return NULL;
}
} else {
return crm_element_value(xml, PCMK__XA_ATTR_SYNC_POINT);
}
}
/*!
* \internal
* \brief Does an IPC request contain any sync point attribute?
*
* \param[in] xml An XML IPC request
*
* \return true if there's a sync point attribute, false otherwise
*/
bool
attrd_request_has_sync_point(xmlNode *xml)
{
return attrd_request_sync_point(xml) != NULL;
}
static void
free_action(gpointer data)
{
struct confirmation_action *action = (struct confirmation_action *) data;
g_list_free_full(action->respondents, free);
+ mainloop_timer_del(action->timer);
free_xml(action->xml);
free(action->client_id);
free(action);
}
+/* Remove an IPC request from the expected_confirmations table if the peer attrds
+ * don't respond before the timeout is hit. We set the timeout to 15s. The exact
+ * number isn't critical - we just want to make sure that the table eventually gets
+ * cleared of things that didn't complete.
+ */
+static gboolean
+confirmation_timeout_cb(gpointer data)
+{
+ struct confirmation_action *action = (struct confirmation_action *) data;
+
+ GHashTableIter iter;
+ gpointer value;
+
+ if (expected_confirmations == NULL) {
+ return G_SOURCE_REMOVE;
+ }
+
+ g_hash_table_iter_init(&iter, expected_confirmations);
+
+ while (g_hash_table_iter_next(&iter, NULL, &value)) {
+ if (value == action) {
+ pcmk__client_t *client = pcmk__find_client_by_id(action->client_id);
+ if (client == NULL) {
+ return G_SOURCE_REMOVE;
+ }
+
+ crm_trace("Timed out waiting for confirmations for client %s", client->id);
+ pcmk__ipc_send_ack(client, action->ipc_id, action->flags | crm_ipc_client_response,
+ "ack", ATTRD_PROTOCOL_VERSION, CRM_EX_TIMEOUT);
+
+ g_hash_table_iter_remove(&iter);
+ crm_trace("%d requests now in expected confirmations table", g_hash_table_size(expected_confirmations));
+ break;
+ }
+ }
+
+ return G_SOURCE_REMOVE;
+}
+
/*!
* \internal
* \brief When a peer disconnects from the cluster, no longer wait for its confirmation
* for any IPC action. If this peer is the last one being waited on, this will
* trigger the confirmation action.
*
* \param[in] host The disconnecting peer attrd's uname
*/
void
attrd_do_not_expect_from_peer(const char *host)
{
GList *keys = g_hash_table_get_keys(expected_confirmations);
crm_trace("Removing peer %s from expected confirmations", host);
for (GList *node = keys; node != NULL; node = node->next) {
int callid = *(int *) node->data;
attrd_handle_confirmation(callid, host);
}
g_list_free(keys);
}
/*!
* \internal
* \brief When a client disconnects from the cluster, no longer wait on confirmations
* for it. Because the peer attrds may still be processing the original IPC
* message, they may still send us confirmations. However, we will take no
* action on them.
*
* \param[in] client The disconnecting client
*/
void
attrd_do_not_wait_for_client(pcmk__client_t *client)
{
GHashTableIter iter;
gpointer value;
if (expected_confirmations == NULL) {
return;
}
g_hash_table_iter_init(&iter, expected_confirmations);
while (g_hash_table_iter_next(&iter, NULL, &value)) {
struct confirmation_action *action = (struct confirmation_action *) value;
if (pcmk__str_eq(action->client_id, client->id, pcmk__str_none)) {
crm_trace("Removing client %s from expected confirmations", client->id);
g_hash_table_iter_remove(&iter);
crm_trace("%d requests now in expected confirmations table", g_hash_table_size(expected_confirmations));
break;
}
}
}
/*!
* \internal
* \brief Register some action to be taken when IPC request confirmations are
* received
*
* When this function is called, a list of all peer attrds that support confirming
* requests is generated. As confirmations from these peer attrds are received,
* they are removed from this list. When the list is empty, the registered action
* will be called.
*
* \note This function should always be called before attrd_send_message is called
* to broadcast to the peers to ensure that we know what replies we are
* waiting on. Otherwise, it is possible the peer could finish and confirm
* before we know to expect it.
*
* \param[in] request The request that is awaiting confirmations
* \param[in] fn A function to be run after all confirmations are received
*/
void
attrd_expect_confirmations(pcmk__request_t *request, attrd_confirmation_action_fn fn)
{
struct confirmation_action *action = NULL;
GHashTableIter iter;
gpointer host, ver;
GList *respondents = NULL;
int callid;
if (expected_confirmations == NULL) {
expected_confirmations = pcmk__intkey_table((GDestroyNotify) free_action);
}
if (crm_element_value_int(request->xml, XML_LRM_ATTR_CALLID, &callid) == -1) {
crm_err("Could not get callid from xml");
return;
}
if (pcmk__intkey_table_lookup(expected_confirmations, callid)) {
crm_err("Already waiting on confirmations for call id %d", callid);
return;
}
g_hash_table_iter_init(&iter, peer_protocol_vers);
while (g_hash_table_iter_next(&iter, &host, &ver)) {
if (ATTRD_SUPPORTS_CONFIRMATION(GPOINTER_TO_INT(ver))) {
char *s = strdup((char *) host);
CRM_ASSERT(s != NULL);
respondents = g_list_prepend(respondents, s);
}
}
action = calloc(1, sizeof(struct confirmation_action));
CRM_ASSERT(action != NULL);
action->respondents = respondents;
action->fn = fn;
action->xml = copy_xml(request->xml);
action->client_id = strdup(request->ipc_client->id);
CRM_ASSERT(action->client_id != NULL);
action->ipc_id = request->ipc_id;
action->flags = request->flags;
+ action->timer = mainloop_timer_add(NULL, 15000, FALSE, confirmation_timeout_cb, action);
+ mainloop_timer_start(action->timer);
+
pcmk__intkey_table_insert(expected_confirmations, callid, action);
crm_trace("Callid %d now waiting on %d confirmations", callid, g_list_length(respondents));
crm_trace("%d requests now in expected confirmations table", g_hash_table_size(expected_confirmations));
}
void
attrd_free_confirmations(void)
{
if (expected_confirmations != NULL) {
g_hash_table_destroy(expected_confirmations);
expected_confirmations = NULL;
}
}
/*!
* \internal
* \brief Process a confirmation message from a peer attrd
*
* This function is called every time a PCMK__ATTRD_CMD_CONFIRM message is
* received from a peer attrd. If this is the last confirmation we are waiting
* on for a given operation, the registered action will be called.
*
* \param[in] callid The unique callid for the XML IPC request
* \param[in] host The confirming peer attrd's uname
*/
void
attrd_handle_confirmation(int callid, const char *host)
{
struct confirmation_action *action = NULL;
GList *node = NULL;
if (expected_confirmations == NULL) {
return;
}
action = pcmk__intkey_table_lookup(expected_confirmations, callid);
if (action == NULL) {
return;
}
node = g_list_find_custom(action->respondents, host, (GCompareFunc) strcasecmp);
if (node == NULL) {
return;
}
action->respondents = g_list_remove(action->respondents, node->data);
crm_trace("Callid %d now waiting on %d confirmations", callid, g_list_length(action->respondents));
if (action->respondents == NULL) {
action->fn(action->xml);
pcmk__intkey_table_remove(expected_confirmations, callid);
crm_trace("%d requests now in expected confirmations table", g_hash_table_size(expected_confirmations));
}
}

File Metadata

Mime Type
text/x-diff
Expires
Thu, Jul 10, 1:35 AM (1 d, 23 m)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
2009544
Default Alt Text
(17 KB)

Event Timeline