Merge pull request #20953 from msekletar/mount-ratelimit-followup-20329

Delay running mount start jobs when we /p/s/mountinfo event source is rate limited

src/core/automount.c

@@ -1063,7 +1063,7 @@ static bool automount_supported(void) {
         return supported;
 }
 
-static int automount_test_start_limit(Unit *u) {
+static int automount_can_start(Unit *u) {
         Automount *a = AUTOMOUNT(u);
         int r;
 
@@ -1075,7 +1075,7 @@ static int automount_test_start_limit(Unit *u) {
                 return r;
         }
 
-        return 0;
+        return 1;
 }
 
 static const char* const automount_result_table[_AUTOMOUNT_RESULT_MAX] = {
@@ -1142,5 +1142,5 @@ const UnitVTable automount_vtable = {
                 },
         },
 
-        .test_start_limit = automount_test_start_limit,
+        .can_start = automount_can_start,
 };

src/core/mount.c

@@ -1838,6 +1838,21 @@ static bool mount_is_mounted(Mount *m) {
         return UNIT(m)->perpetual || FLAGS_SET(m->proc_flags, MOUNT_PROC_IS_MOUNTED);
 }
 
+static int mount_on_ratelimit_expire(sd_event_source *s, void *userdata) {
+        Manager *m = userdata;
+        int r;
+
+        assert(m);
+
+        /* By entering ratelimited state we made all mount start jobs not runnable, now rate limit is over so let's
+         * make sure we dispatch them in the next iteration. */
+        r = sd_event_source_set_enabled(m->run_queue_event_source, SD_EVENT_ONESHOT);
+        if (r < 0)
+                log_debug_errno(r, "Failed to enable run queue event source, ignoring: %m");
+
+        return 0;
+}
+
 static void mount_enumerate(Manager *m) {
         int r;
 
@@ -1891,6 +1906,12 @@ static void mount_enumerate(Manager *m) {
                         goto fail;
                 }
 
+                r = sd_event_source_set_ratelimit_expire_callback(m->mount_event_source, mount_on_ratelimit_expire);
+                if (r < 0) {
+                         log_error_errno(r, "Failed to enable rate limit for mount events: %m");
+                         goto fail;
+                }
+
                 (void) sd_event_source_set_description(m->mount_event_source, "mount-monitor-dispatch");
         }
 
@@ -2135,19 +2156,22 @@ static int mount_can_clean(Unit *u, ExecCleanMask *ret) {
         return exec_context_get_clean_mask(&m->exec_context, ret);
 }
 
-static int mount_test_start_limit(Unit *u) {
+static int mount_can_start(Unit *u) {
         Mount *m = MOUNT(u);
         int r;
 
         assert(m);
 
+        if (sd_event_source_is_ratelimited(u->manager->mount_event_source))
+                return -EAGAIN;
+
         r = unit_test_start_limit(u);
         if (r < 0) {
                 mount_enter_dead(m, MOUNT_FAILURE_START_LIMIT_HIT);
                 return r;
         }
 
-        return 0;
+        return 1;
 }
 
 static const char* const mount_exec_command_table[_MOUNT_EXEC_COMMAND_MAX] = {
@@ -2248,5 +2272,5 @@ const UnitVTable mount_vtable = {
                 },
         },
 
-        .test_start_limit = mount_test_start_limit,
+        .can_start = mount_can_start,
 };

src/core/path.c

@@ -811,7 +811,7 @@ static void path_reset_failed(Unit *u) {
         p->result = PATH_SUCCESS;
 }
 
-static int path_test_start_limit(Unit *u) {
+static int path_can_start(Unit *u) {
         Path *p = PATH(u);
         int r;
 
@@ -823,7 +823,7 @@ static int path_test_start_limit(Unit *u) {
                 return r;
         }
 
-        return 0;
+        return 1;
 }
 
 static const char* const path_type_table[_PATH_TYPE_MAX] = {
@@ -882,5 +882,5 @@ const UnitVTable path_vtable = {
 
         .bus_set_property = bus_path_set_property,
 
-        .test_start_limit = path_test_start_limit,
+        .can_start = path_can_start,
 };

src/core/service.c

@@ -4482,7 +4482,7 @@ static const char *service_finished_job(Unit *u, JobType t, JobResult result) {
         return NULL;
 }
 
-static int service_test_start_limit(Unit *u) {
+static int service_can_start(Unit *u) {
         Service *s = SERVICE(u);
         int r;
 
@@ -4495,7 +4495,7 @@ static int service_test_start_limit(Unit *u) {
                 return r;
         }
 
-        return 0;
+        return 1;
 }
 
 static const char* const service_restart_table[_SERVICE_RESTART_MAX] = {
@@ -4669,5 +4669,5 @@ const UnitVTable service_vtable = {
                 .finished_job = service_finished_job,
         },
 
-        .test_start_limit = service_test_start_limit,
+        .can_start = service_can_start,
 };

src/core/socket.c

@@ -3427,7 +3427,7 @@ static int socket_can_clean(Unit *u, ExecCleanMask *ret) {
         return exec_context_get_clean_mask(&s->exec_context, ret);
 }
 
-static int socket_test_start_limit(Unit *u) {
+static int socket_can_start(Unit *u) {
         Socket *s = SOCKET(u);
         int r;
 
@@ -3439,7 +3439,7 @@ static int socket_test_start_limit(Unit *u) {
                 return r;
         }
 
-        return 0;
+        return 1;
 }
 
 static const char* const socket_exec_command_table[_SOCKET_EXEC_COMMAND_MAX] = {
@@ -3570,5 +3570,5 @@ const UnitVTable socket_vtable = {
                 },
         },
 
-        .test_start_limit = socket_test_start_limit,
+        .can_start = socket_can_start,
 };

src/core/swap.c

@@ -1581,7 +1581,7 @@ static int swap_can_clean(Unit *u, ExecCleanMask *ret) {
         return exec_context_get_clean_mask(&s->exec_context, ret);
 }
 
-static int swap_test_start_limit(Unit *u) {
+static int swap_can_start(Unit *u) {
         Swap *s = SWAP(u);
         int r;
 
@@ -1593,7 +1593,7 @@ static int swap_test_start_limit(Unit *u) {
                 return r;
         }
 
-        return 0;
+        return 1;
 }
 
 static const char* const swap_exec_command_table[_SWAP_EXEC_COMMAND_MAX] = {
@@ -1692,5 +1692,5 @@ const UnitVTable swap_vtable = {
                 },
         },
 
-        .test_start_limit = swap_test_start_limit,
+        .can_start = swap_can_start,
 };

src/core/timer.c

@@ -889,7 +889,7 @@ static int timer_can_clean(Unit *u, ExecCleanMask *ret) {
         return 0;
 }
 
-static int timer_test_start_limit(Unit *u) {
+static int timer_can_start(Unit *u) {
         Timer *t = TIMER(u);
         int r;
 
@@ -901,7 +901,7 @@ static int timer_test_start_limit(Unit *u) {
                 return r;
         }
 
-        return 0;
+        return 1;
 }
 
 static const char* const timer_base_table[_TIMER_BASE_MAX] = {
@@ -965,5 +965,5 @@ const UnitVTable timer_vtable = {
 
         .bus_set_property = bus_timer_set_property,
 
-        .test_start_limit = timer_test_start_limit,
+        .can_start = timer_can_start,
 };

src/core/unit.c

@@ -1904,9 +1904,9 @@ int unit_start(Unit *u) {
                 return unit_start(following);
         }
 
-        /* Check start rate limiting early so that failure conditions don't cause us to enter a busy loop. */
-        if (UNIT_VTABLE(u)->test_start_limit) {
-                r = UNIT_VTABLE(u)->test_start_limit(u);
+        /* Check our ability to start early so that failure conditions don't cause us to enter a busy loop. */
+        if (UNIT_VTABLE(u)->can_start) {
+                r = UNIT_VTABLE(u)->can_start(u);
                 if (r < 0)
                         return r;
         }

src/core/unit.h

@@ -665,7 +665,7 @@ typedef struct UnitVTable {
 
         /* If this function is set, it's invoked first as part of starting a unit to allow start rate
          * limiting checks to occur before we do anything else. */
-        int (*test_start_limit)(Unit *u);
+        int (*can_start)(Unit *u);
 
         /* The strings to print in status messages */
         UnitStatusMessageFormats status_message_formats;