1 files changed, 35 insertions, 22 deletions

diff --git a/daemons/clvmd/clvmd-singlenode.c b/daemons/clvmd/clvmd-singlenode.c
index 37ddeb01..8e845537 100644
--- a/daemons/clvmd/clvmd-singlenode.c
+++ b/daemons/clvmd/clvmd-singlenode.c
@@ -147,6 +147,8 @@ int _lock_file(const char *file, uint32_t flags);
 
 static int _lock_max = 1;
 static pthread_mutex_t _lock_mutex = PTHREAD_MUTEX_INITIALIZER;
+/* Using one common condition for all locks for simplicity */
+static pthread_cond_t _lock_cond = PTHREAD_COND_INITIALIZER;
 
 /* Real locking */
 static int _lock_resource(const char *resource, int mode, int flags, int *lockid)
@@ -155,11 +157,11 @@ static int _lock_resource(const char *resource, int mode, int flags, int *lockid
 	char **_resources_1;
 	int i, j;
 
-	DEBUGLOG("lock_resource '%s', flags=%d, mode=%d\n",
+	DEBUGLOG("Locking resource %s, flags=%d, mode=%d\n",
 		 resource, flags, mode);
 
- retry:
 	pthread_mutex_lock(&_lock_mutex);
+retry:
 
 	/* look for an existing lock for this resource */
 	for (i = 1; i < _lock_max; ++i) {
@@ -168,12 +170,12 @@ static int _lock_resource(const char *resource, int mode, int flags, int *lockid
 		if (!strcmp(_resources[i], resource)) {
 			if ((_locks[i] & LCK_TYPE_MASK) == LCK_WRITE ||
 			    (_locks[i] & LCK_TYPE_MASK) == LCK_EXCL) {
-				DEBUGLOG("%s already write/exclusively locked...\n", resource);
+				DEBUGLOG("Resource %s already write/exclusively locked...\n", resource);
 				goto maybe_retry;
 			}
 			if ((mode & LCK_TYPE_MASK) == LCK_WRITE ||
 			    (mode & LCK_TYPE_MASK) == LCK_EXCL) {
-				DEBUGLOG("%s already locked and WRITE/EXCL lock requested...\n",
+				DEBUGLOG("Resource %s already locked and WRITE/EXCL lock requested...\n",
 					 resource);
 				goto maybe_retry;
 			}
@@ -181,15 +183,14 @@ static int _lock_resource(const char *resource, int mode, int flags, int *lockid
 	}
 
 	if (i == _lock_max) { /* out of lock slots, extend */
-		_locks_1 = dm_realloc(_locks, 2 * _lock_max * sizeof(int));
-		if (!_locks_1)
-			return 1; /* fail */
+		if (!(_locks_1 = dm_realloc(_locks, 2 * _lock_max * sizeof(int))))
+			goto_bad;
+
 		_locks = _locks_1;
-		_resources_1 = dm_realloc(_resources, 2 * _lock_max * sizeof(char *));
-		if (!_resources_1) {
+		if (!(_resources_1 = dm_realloc(_resources, 2 * _lock_max * sizeof(char *))))
 			/* _locks may get realloc'd twice, but that should be safe */
-			return 1; /* fail */
-		}
+			goto_bad;
+
 		_resources = _resources_1;
 		/* clear the new resource entries */
 		for (j = _lock_max; j < 2 * _lock_max; ++j)
@@ -198,40 +199,52 @@ static int _lock_resource(const char *resource, int mode, int flags, int *lockid
 	}
 
 	/* resource is not currently locked, grab it */
+	if (!(_resources[i] = dm_strdup(resource)))
+		goto_bad;
 
 	*lockid = i;
 	_locks[i] = mode;
-	_resources[i] = dm_strdup(resource);
-
-	DEBUGLOG("%s locked -> %d\n", resource, i);
 
+	DEBUGLOG("Locked resource %s, lockid=%d\n", resource, i);
 	pthread_mutex_unlock(&_lock_mutex);
+
 	return 0;
- maybe_retry:
-	pthread_mutex_unlock(&_lock_mutex);
+
+maybe_retry:
 	if (!(flags & LCK_NONBLOCK)) {
-		usleep(10000);
+		pthread_cond_wait(&_lock_cond, &_lock_mutex);
 		goto retry;
 	}
+bad:
+	DEBUGLOG("Failed to lock resource %s\n", resource);
+	pthread_mutex_unlock(&_lock_mutex);
 
 	return 1; /* fail */
 }
 
 static int _unlock_resource(const char *resource, int lockid)
 {
-	DEBUGLOG("unlock_resource: %s lockid: %x\n", resource, lockid);
-	if(!_resources[lockid]) {
-		DEBUGLOG("(%s) %d not locked\n", resource, lockid);
+	DEBUGLOG("Unlocking resource %s, lockid=%d\n", resource, lockid);
+	pthread_mutex_lock(&_lock_mutex);
+
+	if (!_resources[lockid]) {
+		pthread_mutex_unlock(&_lock_mutex);
+		DEBUGLOG("Resource %s, lockid=%d is not locked\n", resource, lockid);
 		return 1;
 	}
-	if(strcmp(_resources[lockid], resource)) {
-		DEBUGLOG("%d has wrong resource (requested %s, got %s)\n",
+
+	if (strcmp(_resources[lockid], resource)) {
+		pthread_mutex_unlock(&_lock_mutex);
+		DEBUGLOG("Resource %d has wrong resource (requested %s, got %s)\n",
 			 lockid, resource, _resources[lockid]);
 		return 1;
 	}
 
 	dm_free(_resources[lockid]);
 	_resources[lockid] = 0;
+	pthread_cond_broadcast(&_lock_cond); /* wakeup waiters */
+	pthread_mutex_unlock(&_lock_mutex);
+
 	return 0;
 }