From 16e2a5aa3b7947af3f5ca85bc875b08a29b980f7 Mon Sep 17 00:00:00 2001
From: Alasdair Kergon <agk@redhat.com>
Date: Wed, 30 Jan 2008 16:18:37 +0000
Subject: [PATCH] only read labels once between each lock event

---
 lib/cache/lvmcache.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/lib/cache/lvmcache.c b/lib/cache/lvmcache.c
index 59011f6ee..3bb7b63e7 100644
--- a/lib/cache/lvmcache.c
+++ b/lib/cache/lvmcache.c
@@ -225,6 +225,16 @@ static int _info_is_valid(struct lvmcache_info *info)
 	if (info->status & CACHE_INVALID)
 		return 0;
 
+	/*
+	 * The caller must hold the VG lock to manipulate metadata.
+	 * In a cluster, remote nodes sometimes read metadata in the
+	 * knowledge that the controlling node is holding the lock.
+	 * So if the VG appears to be unlocked here, it should be safe
+	 * to use the cached value.
+	 */
+	if (info->vginfo && !vgname_is_locked(info->vginfo->vgname))
+		return 1;
+
 	if (!(info->status & CACHE_LOCKED))
 		return 0;