From: Joey Hess <joeyh@joeyh.name>
Date: Fri, 13 Nov 2015 16:36:37 +0000 (-0400)
Subject: better lock dropping order
X-Git-Tag: archive/raspbian/10.20250416-2+rpi1~1^2~324^2~30
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=e31a51c5bb70e7c9a5d2b13eaf83ae07583056c8;p=git-annex.git

better lock dropping order
---

diff --git a/Utility/LockFile/PidLock.hs b/Utility/LockFile/PidLock.hs
index ac1df253d6..94c70e714d 100644
--- a/Utility/LockFile/PidLock.hs
+++ b/Utility/LockFile/PidLock.hs
@@ -20,7 +20,6 @@ import Utility.PartialPrelude
 import Utility.Exception
 import Utility.Applicative
 import Utility.Directory
-import Utility.ThreadScheduler
 import Utility.Monad
 import Utility.Path
 import Utility.FileMode
@@ -127,10 +126,14 @@ waitLock (Seconds timeout) lockfile = go timeout
 			error $ "Gave up waiting for possibly stale pid lock file " ++ lockfile
 
 dropLock :: LockHandle -> IO ()
-dropLock (LockHandle lockfile fd plh) = do
+dropLock (LockHandle lockfile fd sidelock) = do
+	-- Drop side lock first, at which point the pid lock will be
+	-- considered stale.
+	-- The side lock file cannot be deleted because another process may
+	-- have it open and be waiting to lock it.
+	maybe noop Posix.dropLock sidelock
 	closeFd fd
 	nukeFile lockfile
-	maybe noop Posix.dropLock plh
 
 getLockStatus :: LockFile -> IO LockStatus
 getLockStatus = maybe StatusUnLocked (StatusLockedBy . lockingPid) <$$> readPidLock