From 56942c3f2aafe613c8d12f0ef8d4f7872ebfae5f Mon Sep 17 00:00:00 2001
From: Patrick Caulfield <pcaulfie@redhat.com>
Date: Wed, 22 Sep 2004 12:10:34 +0000
Subject: [PATCH] Put some locking round the LV hash table as it could be
 accessed by different threads concurrently.

---
 daemons/clvmd/lvm-functions.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/daemons/clvmd/lvm-functions.c b/daemons/clvmd/lvm-functions.c
index 4499b6ee6..71988dbff 100644
--- a/daemons/clvmd/lvm-functions.c
+++ b/daemons/clvmd/lvm-functions.c
@@ -46,6 +46,7 @@
 
 static struct cmd_context *cmd = NULL;
 static struct hash_table *lv_hash = NULL;
+static pthread_mutex_t lv_hash_lock;
 
 struct lv_info {
 	int lock_id;
@@ -57,7 +58,9 @@ static int get_current_lock(char *resource)
 {
 	struct lv_info *lvi;
 
+	pthread_mutex_lock(&lv_hash_lock);
 	lvi = hash_lookup(lv_hash, resource);
+	pthread_mutex_unlock(&lv_hash_lock);
 	if (lvi) {
 		return lvi->lock_mode;
 	} else {
@@ -69,11 +72,14 @@ static int get_current_lock(char *resource)
 void unlock_all()
 {
 	struct hash_node *v;
+
+	pthread_mutex_lock(&lv_hash_lock);
 	hash_iterate(v, lv_hash) {
 		struct lv_info *lvi = hash_get_data(lv_hash, v);
 
 		sync_unlock(hash_get_key(lv_hash, v), lvi->lock_id);
 	}
+	pthread_mutex_unlock(&lv_hash_lock);
 }
 
 /* Gets a real lock and keeps the info in the hash table */
@@ -85,7 +91,9 @@ int hold_lock(char *resource, int mode, int flags)
 
 	flags &= LKF_NOQUEUE;	/* Only LKF_NOQUEUE is valid here */
 
+	pthread_mutex_lock(&lv_hash_lock);
 	lvi = hash_lookup(lv_hash, resource);
+	pthread_mutex_unlock(&lv_hash_lock);
 	if (lvi) {
 		/* Already exists - convert it */
 		status =
@@ -113,7 +121,9 @@ int hold_lock(char *resource, int mode, int flags)
 			DEBUGLOG("hold_lock. lock at %d failed: %s\n", mode,
 				 strerror(errno));
 		} else {
+		        pthread_mutex_lock(&lv_hash_lock);
 			hash_insert(lv_hash, resource, lvi);
+			pthread_mutex_unlock(&lv_hash_lock);
 		}
 		errno = saved_errno;
 	}
@@ -127,8 +137,9 @@ int hold_unlock(char *resource)
 	int status;
 	int saved_errno;
 
+	pthread_mutex_lock(&lv_hash_lock);
 	lvi = hash_lookup(lv_hash, resource);
-
+	pthread_mutex_unlock(&lv_hash_lock);
 	if (!lvi) {
 		DEBUGLOG("hold_unlock, lock not already held\n");
 		return 0;
@@ -137,7 +148,9 @@ int hold_unlock(char *resource)
 	status = sync_unlock(resource, lvi->lock_id);
 	saved_errno = errno;
 	if (!status) {
+	    	pthread_mutex_lock(&lv_hash_lock);
 		hash_remove(lv_hash, resource);
+		pthread_mutex_unlock(&lv_hash_lock);
 		free(lvi);
 	} else {
 		DEBUGLOG("hold_unlock. unlock failed(%d): %s\n", status,
@@ -427,6 +440,7 @@ void init_lvhash()
 {
 	/* Create hash table for keeping LV locks & status */
 	lv_hash = hash_create(100);
+	pthread_mutex_init(&lv_hash_lock, NULL);
 }
 
 /* Called to initialise the LVM context of the daemon */
-- 
2.43.5