From fd88588df029604689db9b0e30c55aad68392a5d Mon Sep 17 00:00:00 2001
From: Richard Purdie <richard.purdie@linuxfoundation.org>
Date: Wed, 19 Jan 2011 13:30:14 +0000
Subject: [PATCH] bitbake/utils.py: Teach unlockfile about shared mode
 lockfiles

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
---
 bitbake/lib/bb/utils.py | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/bitbake/lib/bb/utils.py b/bitbake/lib/bb/utils.py
index 5dc7e766f5..c6bbae87a4 100644
--- a/bitbake/lib/bb/utils.py
+++ b/bitbake/lib/bb/utils.py
@@ -445,7 +445,13 @@ def unlockfile(lf):
     """
     Unlock a file locked using lockfile()
     """
-    os.unlink(lf.name)
+    try:
+        # If we had a shared lock, we need to promote to exclusive before 
+        # removing the lockfile. Attempt this, ignore failures.
+        fcntl.flock(lf.fileno(), fcntl.LOCK_EX|fcntl.LOCK_NB)
+        os.unlink(lf.name)
+    except IOError:
+        pass
     fcntl.flock(lf.fileno(), fcntl.LOCK_UN)
     lf.close()