@@ -188,6 +188,7 @@ struct config {
int find_multipaths_timeout;
int marginal_pathgroups;
unsigned int version[3];
+ unsigned int sequence_nr;
char * multipath_dir;
char * selector;
@@ -2618,6 +2618,7 @@ reconfigure (struct vectors * vecs)
uxsock_timeout = conf->uxsock_timeout;
old = rcu_dereference(multipath_conf);
+ conf->sequence_nr = old->sequence_nr + 1;
rcu_assign_pointer(multipath_conf, conf);
call_rcu(&old->rcu, rcu_free_config);
@@ -23,6 +23,7 @@
#include <sys/time.h>
#include <signal.h>
#include <stdbool.h>
+#include <sys/inotify.h>
#include "checkers.h"
#include "memory.h"
#include "debug.h"
@@ -51,6 +52,8 @@ struct client {
LIST_HEAD(clients);
pthread_mutex_t client_lock = PTHREAD_MUTEX_INITIALIZER;
struct pollfd *polls;
+static int notify_fd = -1;
+static char *watch_config_dir;
static bool _socket_client_is_root(int fd);
@@ -151,6 +154,8 @@ void uxsock_cleanup(void *arg)
long ux_sock = (long)arg;
close(ux_sock);
+ close(notify_fd);
+ free(watch_config_dir);
pthread_mutex_lock(&client_lock);
list_for_each_entry_safe(client_loop, client_tmp, &clients, node) {
@@ -162,6 +167,110 @@ void uxsock_cleanup(void *arg)
free_polls();
}
+struct watch_descriptors {
+ int conf_wd;
+ int dir_wd;
+};
+
+/* failing to set the watch descriptor is o.k. we just miss a warning
+ * message */
+static void reset_watch(int notify_fd, struct watch_descriptors *wds,
+ unsigned int *sequence_nr)
+{
+ struct config *conf;
+ int dir_reset = 0;
+ int conf_reset = 0;
+
+ if (notify_fd == -1)
+ return;
+
+ conf = get_multipath_config();
+ /* instead of repeatedly try to reset the inotify watch if
+ * the config directory or multipath.conf isn't there, just
+ * do it once per reconfigure */
+ if (*sequence_nr != conf->sequence_nr) {
+ *sequence_nr = conf->sequence_nr;
+ if (wds->conf_wd == -1)
+ conf_reset = 1;
+ if (!watch_config_dir || !conf->config_dir ||
+ strcmp(watch_config_dir, conf->config_dir)) {
+ dir_reset = 1;
+ if (watch_config_dir)
+ free(watch_config_dir);
+ if (conf->config_dir)
+ watch_config_dir = strdup(conf->config_dir);
+ else
+ watch_config_dir = NULL;
+ } else if (wds->dir_wd == -1)
+ dir_reset = 1;
+ }
+ put_multipath_config(conf);
+
+ if (dir_reset) {
+ if (wds->dir_wd != -1) {
+ inotify_rm_watch(notify_fd, wds->dir_wd);
+ wds->dir_wd = -1;
+ }
+ if (watch_config_dir) {
+ wds->dir_wd = inotify_add_watch(notify_fd,
+ watch_config_dir,
+ IN_CLOSE_WRITE |
+ IN_DELETE | IN_ONLYDIR);
+ if (wds->dir_wd == -1)
+ condlog(3, "didn't set up notifications on %s: %m", watch_config_dir);
+ }
+ }
+ if (conf_reset) {
+ wds->conf_wd = inotify_add_watch(notify_fd, DEFAULT_CONFIGFILE,
+ IN_CLOSE_WRITE);
+ if (wds->conf_wd == -1)
+ condlog(3, "didn't set up notifications on /etc/multipath.conf: %m");
+ }
+ return;
+}
+
+static void handle_inotify(int fd, struct watch_descriptors *wds)
+{
+ char buff[1024]
+ __attribute__ ((aligned(__alignof__(struct inotify_event))));
+ const struct inotify_event *event;
+ ssize_t len;
+ char *ptr;
+ int got_notify = 0;
+
+ for (;;) {
+ len = read(fd, buff, sizeof(buff));
+ if (len <= 0) {
+ if (len < 0 && errno != EAGAIN) {
+ condlog(3, "error reading from inotify_fd");
+ if (wds->conf_wd != -1)
+ inotify_rm_watch(fd, wds->conf_wd);
+ if (wds->dir_wd != -1)
+ inotify_rm_watch(fd, wds->dir_wd);
+ wds->conf_wd = wds->dir_wd = -1;
+ }
+ break;
+ }
+
+ got_notify = 1;
+ for (ptr = buff; ptr < buff + len;
+ ptr += sizeof(struct inotify_event) + event->len) {
+ event = (const struct inotify_event *) ptr;
+
+ if (event->mask & IN_IGNORED) {
+ /* multipathd.conf may have been overwritten.
+ * Try once to reset the notification */
+ if (wds->conf_wd == event->wd)
+ wds->conf_wd = inotify_add_watch(notify_fd, DEFAULT_CONFIGFILE, IN_CLOSE_WRITE);
+ else if (wds->dir_wd == event->wd)
+ wds->dir_wd = -1;
+ }
+ }
+ }
+ if (got_notify)
+ condlog(1, "Multipath configuration updated.\nReload multipathd for changes to take effect");
+}
+
/*
* entry point
*/
@@ -173,13 +282,19 @@ void * uxsock_listen(uxsock_trigger_fn uxsock_trigger, long ux_sock,
char *reply;
sigset_t mask;
int old_clients = MIN_POLLS;
+ /* conf->sequence_nr will be 1 when uxsock_listen is first called */
+ unsigned int sequence_nr = 0;
+ struct watch_descriptors wds = { .conf_wd = -1, .dir_wd = -1 };
condlog(3, "uxsock: startup listener");
- polls = (struct pollfd *)MALLOC((MIN_POLLS + 1) * sizeof(struct pollfd));
+ polls = (struct pollfd *)MALLOC((MIN_POLLS + 2) * sizeof(struct pollfd));
if (!polls) {
condlog(0, "uxsock: failed to allocate poll fds");
exit_daemon();
}
+ notify_fd = inotify_init1(IN_NONBLOCK);
+ if (notify_fd == -1) /* it's fine if notifications fail */
+ condlog(3, "failed to start up configuration notifications");
sigfillset(&mask);
sigdelset(&mask, SIGINT);
sigdelset(&mask, SIGTERM);
@@ -198,18 +313,18 @@ void * uxsock_listen(uxsock_trigger_fn uxsock_trigger, long ux_sock,
if (num_clients != old_clients) {
struct pollfd *new;
if (num_clients <= MIN_POLLS && old_clients > MIN_POLLS) {
- new = REALLOC(polls, (1 + MIN_POLLS) *
+ new = REALLOC(polls, (2 + MIN_POLLS) *
sizeof(struct pollfd));
} else if (num_clients <= MIN_POLLS && old_clients <= MIN_POLLS) {
new = polls;
} else {
- new = REALLOC(polls, (1+num_clients) *
+ new = REALLOC(polls, (2 + num_clients) *
sizeof(struct pollfd));
}
if (!new) {
pthread_mutex_unlock(&client_lock);
condlog(0, "%s: failed to realloc %d poll fds",
- "uxsock", 1 + num_clients);
+ "uxsock", 2 + num_clients);
sched_yield();
continue;
}
@@ -219,8 +334,15 @@ void * uxsock_listen(uxsock_trigger_fn uxsock_trigger, long ux_sock,
polls[0].fd = ux_sock;
polls[0].events = POLLIN;
+ reset_watch(notify_fd, &wds, &sequence_nr);
+ if (notify_fd == -1 || (wds.conf_wd == -1 && wds.dir_wd == -1))
+ polls[1].fd = -1;
+ else
+ polls[1].fd = notify_fd;
+ polls[1].events = POLLIN;
+
/* setup the clients */
- i = 1;
+ i = 2;
list_for_each_entry(c, &clients, node) {
polls[i].fd = c->fd;
polls[i].events = POLLIN;
@@ -262,7 +384,7 @@ void * uxsock_listen(uxsock_trigger_fn uxsock_trigger, long ux_sock,
}
/* see if a client wants to speak to us */
- for (i = 1; i < num_clients + 1; i++) {
+ for (i = 2; i < num_clients + 2; i++) {
if (polls[i].revents & POLLIN) {
struct timespec start_time;
@@ -321,6 +443,10 @@ void * uxsock_listen(uxsock_trigger_fn uxsock_trigger, long ux_sock,
if (polls[0].revents & POLLIN) {
new_client(ux_sock);
}
+
+ /* handle inotify events on config files */
+ if (polls[1].revents & POLLIN)
+ handle_inotify(notify_fd, &wds);
}
return NULL;
It would be helpful if multipathd could log a message when multipath.conf or files in the config_dir have been written to, both so that it can be used to send a notification to users, and to help with determining after the fact if multipathd was running with an older config, when the logs of multipathd's behaviour don't match with the current multipath.conf. To do this, the multipathd uxlsnr thread now sets up inotify watches on both /etc/multipath.conf and the config_dir to watch if the files are deleted or closed after being opened for writing. In order to keep uxlsnr from polling repeatedly if the multipath.conf or the config_dir aren't present, it will only set up the watches once per reconfigure. However, since multipath.conf is far more likely to be replaced by a text editor than modified in place, if it gets removed, multipathd will immediately try to restart the watch on it (which will succeed if the file was simply replaced by a new copy). This does mean that if multipath.conf or the config_dir are actually removed and then later re-added, multipathd won't log any more messages for changes until the next reconfigure. But that seems like a fair trade-off to avoid repeatedly polling for files that aren't likely to appear. Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com> --- libmultipath/config.h | 1 + multipathd/main.c | 1 + multipathd/uxlsnr.c | 138 ++++++++++++++++++++++++++++++++++++++++-- 3 files changed, 134 insertions(+), 6 deletions(-)