dlm: fix locking of lockspace list in dlm_scand

The dlm_scand thread needs to lock the list of lockspaces when going through it. Signed-off-by: David Teigland <teigland@redhat.com>

dlm: fix locking of lockspace list in dlm_scand
The dlm_scand thread needs to lock the list of lockspaces when going through it. Signed-off-by: David Teigland <teigland@redhat.com>
David Teigland
1 parent dc68c7ed36
Showing 2 changed files with 26 additions and 2 deletions Side-by-side Diff
fs/dlm/dlm_internal.h
fs/dlm/lockspace.c
@@ -445,6 +445,7 @@
 						   the dlm using this ls */
 	int			ls_create_count; /* create/release refcount */
 	unsigned long		ls_flags;	/* LSFL_ */
+	unsigned long		ls_scan_time;
 	struct kobject		ls_kobj;
  
 	struct dlm_rsbtable	*ls_rsbtbl;
@@ -212,19 +212,41 @@
 	kset_unregister(dlm_kset);
 }
  
+static struct dlm_ls *find_ls_to_scan(void)
+{
+	struct dlm_ls *ls;
+
+	spin_lock(&lslist_lock);
+	list_for_each_entry(ls, &lslist, ls_list) {
+		if (time_after_eq(jiffies, ls->ls_scan_time +
+					    dlm_config.ci_scan_secs * HZ)) {
+			spin_unlock(&lslist_lock);
+			return ls;
+		}
+	}
+	spin_unlock(&lslist_lock);
+	return NULL;
+}
+
 static int dlm_scand(void *data)
 {
 	struct dlm_ls *ls;
+	int timeout_jiffies = dlm_config.ci_scan_secs * HZ;
  
 	while (!kthread_should_stop()) {
-		list_for_each_entry(ls, &lslist, ls_list) {
+		ls = find_ls_to_scan();
+		if (ls) {
 			if (dlm_lock_recovery_try(ls)) {
+				ls->ls_scan_time = jiffies;
 				dlm_scan_rsbs(ls);
 				dlm_scan_timeout(ls);
 				dlm_unlock_recovery(ls);
+			} else {
+				ls->ls_scan_time += HZ;
 			}
+		} else {
+			schedule_timeout_interruptible(timeout_jiffies);
 		}
-		schedule_timeout_interruptible(dlm_config.ci_scan_secs * HZ);
 	}
 	return 0;
 }
@@ -418,6 +440,7 @@
 	ls->ls_lvblen = lvblen;
 	ls->ls_count = 0;
 	ls->ls_flags = 0;
+	ls->ls_scan_time = jiffies;
  
 	if (flags & DLM_LSFL_TIMEWARN)
 		set_bit(LSFL_TIMEWARN, &ls->ls_flags);
...	...	@@ -445,6 +445,7 @@
445	445	the dlm using this ls */
446	446	int ls_create_count; /* create/release refcount */
447	447	unsigned long ls_flags; /* LSFL_ */
	448	+ unsigned long ls_scan_time;
448	449	struct kobject ls_kobj;
449	450
450	451	struct dlm_rsbtable *ls_rsbtbl;
...	...	@@ -212,19 +212,41 @@
212	212	kset_unregister(dlm_kset);
213	213	}
214	214
	215	+static struct dlm_ls *find_ls_to_scan(void)
	216	+{
	217	+ struct dlm_ls *ls;
	218	+
	219	+ spin_lock(&lslist_lock);
	220	+ list_for_each_entry(ls, &lslist, ls_list) {
	221	+ if (time_after_eq(jiffies, ls->ls_scan_time +
	222	+ dlm_config.ci_scan_secs * HZ)) {
	223	+ spin_unlock(&lslist_lock);
	224	+ return ls;
	225	+ }
	226	+ }
	227	+ spin_unlock(&lslist_lock);
	228	+ return NULL;
	229	+}
	230	+
215	231	static int dlm_scand(void *data)
216	232	{
217	233	struct dlm_ls *ls;
	234	+ int timeout_jiffies = dlm_config.ci_scan_secs * HZ;
218	235
219	236	while (!kthread_should_stop()) {
220		- list_for_each_entry(ls, &lslist, ls_list) {
	237	+ ls = find_ls_to_scan();
	238	+ if (ls) {
221	239	if (dlm_lock_recovery_try(ls)) {
	240	+ ls->ls_scan_time = jiffies;
222	241	dlm_scan_rsbs(ls);
223	242	dlm_scan_timeout(ls);
224	243	dlm_unlock_recovery(ls);
	244	+ } else {
	245	+ ls->ls_scan_time += HZ;
225	246	}
	247	+ } else {
	248	+ schedule_timeout_interruptible(timeout_jiffies);
226	249	}
227		- schedule_timeout_interruptible(dlm_config.ci_scan_secs * HZ);
228	250	}
229	251	return 0;
230	252	}
...	...	@@ -418,6 +440,7 @@
418	440	ls->ls_lvblen = lvblen;
419	441	ls->ls_count = 0;
420	442	ls->ls_flags = 0;
	443	+ ls->ls_scan_time = jiffies;
421	444
422	445	if (flags & DLM_LSFL_TIMEWARN)
423	446	set_bit(LSFL_TIMEWARN, &ls->ls_flags);