Fix bug that prevented transfer locks from working when run on SMB or other filesystem that does not support fcntl locks and hard links.

This commit was sponsored by Ethan Aubin.

Utility/LockFile/PidLock.hs

@@ -122,18 +122,21 @@ tryLock lockfile = trySideLock lockfile $ \sidelock -> do
 	setFileMode tmp (combineModes readModes)
 	hPutStr h . show =<< mkPidLock
 	hClose h
-	st <- getFileStatus tmp
-	let failedlock = do
+	let failedlock st = do
 		dropLock $ LockHandle tmp st sidelock
 		return Nothing
-	let tooklock = return $ Just $ LockHandle lockfile' st sidelock
+	let tooklock st = return $ Just $ LockHandle lockfile' st sidelock
 	ifM (linkToLock sidelock tmp lockfile')
 		( do
 			nukeFile tmp
-			tooklock
+			-- May not have made a hard link, so stat
+			-- the lockfile
+			lckst <- getFileStatus lockfile'
+			tooklock lckst
 		, do
 			v <- readPidLock lockfile'
 			hn <- getHostName
+			tmpst <- getFileStatus tmp
 			case v of
 				Just pl | isJust sidelock && hn == lockingHost pl -> do
 					-- Since we have the sidelock,
@@ -142,8 +145,8 @@ tryLock lockfile = trySideLock lockfile $ \sidelock -> do
 					-- we know that the pidlock is
 					-- stale, and can take it over.
 					rename tmp lockfile'
-					tooklock
-				_ -> failedlock
+					tooklock tmpst
+				_ -> failedlock tmpst
 		)
 
 -- Linux's open(2) man page recommends linking a pid lock into place,