avoid confusing git with a modified ctime in clean filter

Linking the file to the tmp dir was not necessary in the clean
filter, and it caused the ctime to change, which caused git to think
the file was changed. This caused git status to get slow as it kept
re-cleaning unchanged files.

Annex/Ingest.hs

@@ -9,6 +9,7 @@
 
 module Annex.Ingest (
 	LockedDown(..),
+	LockDownConfig(..),
 	lockDown,
 	ingest,
 	finishIngestDirect,
@@ -48,11 +49,17 @@ import Utility.Touch
 import Control.Exception (IOException)
 
 data LockedDown = LockedDown
-	{ lockingFile :: Bool
+	{ lockDownConfig :: LockDownConfig
 	, keySource :: KeySource
 	}
 	deriving (Show)
 
+data LockDownConfig = LockDownConfig
+	{ lockingFile :: Bool -- ^ write bit removed during lock down
+	, hardlinkFileTmp :: Bool -- ^ hard link to temp directory
+	}
+	deriving (Show)
+
 {- The file that's being ingested is locked down before a key is generated,
  - to prevent it from being modified in between. This lock down is not
  - perfect at best (and pretty weak at worst). For example, it does not
@@ -64,24 +71,21 @@ data LockedDown = LockedDown
  - against some changes, like deletion or overwrite of the file, and
  - allows lsof checks to be done more efficiently when adding a lot of files.
  -
- - If lockingfile is True, the file is going to be added in locked mode.
- - So, its write bit is removed as part of the lock down.
- -
  - Lockdown can fail if a file gets deleted, and Nothing will be returned.
  -}
-lockDown :: Bool -> FilePath -> Annex (Maybe LockedDown)
-lockDown lockingfile file = either 
+lockDown :: LockDownConfig -> FilePath -> Annex (Maybe LockedDown)
+lockDown cfg file = either 
 		(\e -> warning (show e) >> return Nothing)
 		(return . Just)
-	=<< lockDown' lockingfile file
+	=<< lockDown' cfg file
 
-lockDown' :: Bool -> FilePath -> Annex (Either IOException LockedDown)
-lockDown' lockingfile file = ifM crippledFileSystem
+lockDown' :: LockDownConfig -> FilePath -> Annex (Either IOException LockedDown)
+lockDown' cfg file = ifM (pure (not (hardlinkFileTmp cfg)) <||> crippledFileSystem)
 	( withTSDelta $ liftIO . tryIO . nohardlink
 	, tryIO $ do
 		tmp <- fromRepo gitAnnexTmpMiscDir
 		createAnnexDirectory tmp
-		when lockingfile $
+		when (lockingFile cfg) $
 			freezeContent file
 		withTSDelta $ \delta -> liftIO $ do
 			(tmpfile, h) <- openTempFile tmp $
@@ -93,7 +97,7 @@ lockDown' lockingfile file = ifM crippledFileSystem
   where
 	nohardlink delta = do
 		cache <- genInodeCache file delta
-		return $ LockedDown lockingfile $ KeySource
+		return $ LockedDown cfg $ KeySource
 			{ keyFilename = file
 			, contentLocation = file
 			, inodeCache = cache
@@ -101,7 +105,7 @@ lockDown' lockingfile file = ifM crippledFileSystem
 	withhardlink delta tmpfile = do
 		createLink file tmpfile
 		cache <- genInodeCache tmpfile delta
-		return $ LockedDown lockingfile $ KeySource
+		return $ LockedDown cfg $ KeySource
 			{ keyFilename = file
 			, contentLocation = tmpfile
 			, inodeCache = cache
@@ -115,7 +119,7 @@ lockDown' lockingfile file = ifM crippledFileSystem
  -}
 ingest :: Maybe LockedDown -> Annex (Maybe Key, Maybe InodeCache)
 ingest Nothing = return (Nothing, Nothing)
-ingest (Just (LockedDown lockingfile source)) = withTSDelta $ \delta -> do
+ingest (Just (LockedDown cfg source)) = withTSDelta $ \delta -> do
 	backend <- chooseBackend $ keyFilename source
 	k <- genKey source backend
 	let src = contentLocation source
@@ -127,7 +131,7 @@ ingest (Just (LockedDown lockingfile source)) = withTSDelta $ \delta -> do
 		_ -> failure "changed while it was being added"
   where
 	go (Just (key, _)) mcache (Just s)
-		| lockingfile = golocked key mcache s
+		| lockingFile cfg = golocked key mcache s
 		| otherwise = ifM isDirect
 			( godirect key mcache s
 			, gounlocked key mcache s