replace (Key, Backend) with Key

Only fsck and reinject and the test suite used the Backend, and they can
look it up as needed from the Key. This simplifies the code and also speeds
it up.

There is a small behavior change here. Before, all commands would warn when
acting on an annexed file with an unknown backend. Now, only fsck and
reinject show that warning.

33 files changed, 112 insertions, 94 deletions

diff --git a/Annex/View.hs b/Annex/View.hs
index 7c187befd..5cf21cdfe 100644
--- a/Annex/View.hs
+++ b/Annex/View.hs
@@ -348,7 +348,7 @@ applyView' mkviewedfile getfilemetadata view = do
 			void clean
   where
 	genviewedfiles = viewedFiles view mkviewedfile -- enables memoization
-	go uh hasher f (Just (k, _)) = do
+	go uh hasher f (Just k) = do
 		metadata <- getCurrentMetaData k
 		let metadata' = getfilemetadata f `unionMetaData` metadata
 		forM_ (genviewedfiles f metadata') $ \fv -> do
diff --git a/Assistant/Threads/TransferScanner.hs b/Assistant/Threads/TransferScanner.hs
index 6df9b1e18..daced8d21 100644
--- a/Assistant/Threads/TransferScanner.hs
+++ b/Assistant/Threads/TransferScanner.hs
@@ -151,7 +151,7 @@ expensiveScan urlrenderer rs = unless onlyweb $ batch <~> do
 	enqueue f (r, t) =
 		queueTransferWhenSmall "expensive scan found missing object"
 			(Just f) t r
-	findtransfers f unwanted (key, _) = do
+	findtransfers f unwanted key = do
 		{- The syncable remotes may have changed since this
 		 - scan began. -}
 		syncrs <- syncDataRemotes <$> getDaemonStatus
diff --git a/Assistant/Threads/Watcher.hs b/Assistant/Threads/Watcher.hs
index 97ccf083e..0ed1bd22f 100644
--- a/Assistant/Threads/Watcher.hs
+++ b/Assistant/Threads/Watcher.hs
@@ -271,7 +271,7 @@ onAddSymlink :: Bool -> Handler
 onAddSymlink isdirect file filestatus = unlessIgnored file $ do
 	linktarget <- liftIO (catchMaybeIO $ readSymbolicLink file)
 	kv <- liftAnnex (Backend.lookupFile file)
-	onAddSymlink' linktarget (fmap fst kv) isdirect file filestatus
+	onAddSymlink' linktarget kv isdirect file filestatus
 
 onAddSymlink' :: Maybe String -> Maybe Key -> Bool -> Handler
 onAddSymlink' linktarget mk isdirect file filestatus = go mk
diff --git a/Backend.hs b/Backend.hs
index 38314687a..dded0d005 100644
--- a/Backend.hs
+++ b/Backend.hs
@@ -1,6 +1,6 @@
 {- git-annex key/value backends
  -
- - Copyright 2010,2013 Joey Hess <joey@kitenet.net>
+ - Copyright 2010-2014 Joey Hess <joey@kitenet.net>
  -
  - Licensed under the GNU GPL version 3 or higher.
  -}
@@ -10,6 +10,7 @@ module Backend (
 	orderedList,
 	genKey,
 	lookupFile,
+	getBackend,
 	isAnnexLink,
 	chooseBackend,
 	lookupBackendName,
@@ -74,7 +75,7 @@ genKey' (b:bs) source = do
 		| c == '\n' = '_'
 		| otherwise = c
 
-{- Looks up the key and backend corresponding to an annexed file,
+{- Looks up the key corresponding to an annexed file,
  - by examining what the file links to.
  -
  - In direct mode, there is often no link on disk, in which case
@@ -82,7 +83,7 @@ genKey' (b:bs) source = do
  - on disk still takes precedence over what was committed to git in direct
  - mode.
  -}
-lookupFile :: FilePath -> Annex (Maybe (Key, Backend))
+lookupFile :: FilePath -> Annex (Maybe Key)
 lookupFile file = do
 	mkey <- isAnnexLink file
 	case mkey of
@@ -92,14 +93,15 @@ lookupFile file = do
 			, return Nothing
 			)
   where
-	makeret k = let bname = keyBackendName k in
-		case maybeLookupBackendName bname of
-			Just backend -> return $ Just (k, backend)
-			Nothing -> do
-				warning $
-					"skipping " ++ file ++
-					" (unknown backend " ++ bname ++ ")"
-				return Nothing
+	makeret k = return $ Just k
+
+getBackend :: FilePath -> Key -> Annex (Maybe Backend)
+getBackend file k = let bname = keyBackendName k in
+	case maybeLookupBackendName bname of
+		Just backend -> return $ Just backend
+		Nothing -> do
+			warning $ "skipping " ++ file ++ " (unknown backend " ++ bname ++ ")"
+			return Nothing
 
 {- Looks up the backend that should be used for a file.
  - That can be configured on a per-file basis in the gitattributes file. -}
diff --git a/Command.hs b/Command.hs
index 3faa4053c..fc440f291 100644
--- a/Command.hs
+++ b/Command.hs
@@ -70,11 +70,11 @@ stopUnless :: Annex Bool -> Annex (Maybe a) -> Annex (Maybe a)
 stopUnless c a = ifM c ( a , stop )
 
 {- Modifies an action to only act on files that are already annexed,
- - and passes the key and backend on to it. -}
-whenAnnexed :: (FilePath -> (Key, Backend) -> Annex (Maybe a)) -> FilePath -> Annex (Maybe a)
+ - and passes the key on to it. -}
+whenAnnexed :: (FilePath -> Key -> Annex (Maybe a)) -> FilePath -> Annex (Maybe a)
 whenAnnexed a file = ifAnnexed file (a file) (return Nothing)
 
-ifAnnexed :: FilePath -> ((Key, Backend) -> Annex a) -> Annex a -> Annex a
+ifAnnexed :: FilePath -> (Key -> Annex a) -> Annex a -> Annex a
 ifAnnexed file yes no = maybe no yes =<< Backend.lookupFile file
 
 isBareRepo :: Annex Bool
diff --git a/Command/Add.hs b/Command/Add.hs
index f9e2b3342..46a873151 100644
--- a/Command/Add.hs
+++ b/Command/Add.hs
@@ -73,7 +73,7 @@ start file = ifAnnexed file addpresent add
 				| otherwise -> do
 					showStart "add" file
 					next $ perform file
-	addpresent (key, _) = ifM isDirect
+	addpresent key = ifM isDirect
 		( ifM (goodContent key file) ( stop , add )
 		, fixup key
 		)
diff --git a/Command/AddUrl.hs b/Command/AddUrl.hs
index b108be507..7ffb86997 100644
--- a/Command/AddUrl.hs
+++ b/Command/AddUrl.hs
@@ -96,7 +96,7 @@ performQuvi :: Bool -> URLString -> URLString -> FilePath -> CommandPerform
 performQuvi relaxed pageurl videourl file = ifAnnexed file addurl geturl
   where
   	quviurl = setDownloader pageurl QuviDownloader
-  	addurl (key, _backend) = next $ cleanup quviurl file key Nothing
+  	addurl key = next $ cleanup quviurl file key Nothing
 	geturl = next $ addUrlFileQuvi relaxed quviurl videourl file
 #endif
 
@@ -130,7 +130,7 @@ perform :: Bool -> URLString -> FilePath -> CommandPerform
 perform relaxed url file = ifAnnexed file addurl geturl
   where
 	geturl = next $ addUrlFile relaxed url file
-	addurl (key, _backend)
+	addurl key
 		| relaxed = do
 			setUrlPresent key url
 			next $ return True
diff --git a/Command/Copy.hs b/Command/Copy.hs
index 29606061d..ae254aae2 100644
--- a/Command/Copy.hs
+++ b/Command/Copy.hs
@@ -30,9 +30,9 @@ seek ps = do
 {- A copy is just a move that does not delete the source file.
  - However, --auto mode avoids unnecessary copies, and avoids getting or
  - sending non-preferred content. -}
-start :: Maybe Remote -> Maybe Remote -> FilePath -> (Key, Backend) -> CommandStart
-start to from file (key, backend) = stopUnless shouldCopy $ 
-	Command.Move.start to from False file (key, backend)
+start :: Maybe Remote -> Maybe Remote -> FilePath -> Key -> CommandStart
+start to from file key = stopUnless shouldCopy $ 
+	Command.Move.start to from False file key
   where
 	shouldCopy = checkAuto (check <||> numCopiesCheck file key (<))
 	check = case to of
diff --git a/Command/Direct.hs b/Command/Direct.hs
index 47f622a81..9727549b6 100644
--- a/Command/Direct.hs
+++ b/Command/Direct.hs
@@ -47,7 +47,7 @@ perform = do
 	void $ liftIO clean
 	next cleanup
   where
-	go = whenAnnexed $ \f (k, _) -> do
+	go = whenAnnexed $ \f k -> do
 		r <- toDirectGen k f
 		case r of
 			Nothing -> noop
diff --git a/Command/Drop.hs b/Command/Drop.hs
index 71f19a828..4bac07a53 100644
--- a/Command/Drop.hs
+++ b/Command/Drop.hs
@@ -34,8 +34,8 @@ seek ps = do
 	from <- getOptionField dropFromOption Remote.byNameWithUUID
 	withFilesInGit (whenAnnexed $ start from) ps
 
-start :: Maybe Remote -> FilePath -> (Key, Backend) -> CommandStart
-start from file (key, _) = checkDropAuto from file key $ \numcopies ->
+start :: Maybe Remote -> FilePath -> Key -> CommandStart
+start from file key = checkDropAuto from file key $ \numcopies ->
 	stopUnless (checkAuto $ wantDrop False (Remote.uuid <$> from) (Just key) (Just file)) $
 		case from of
 			Nothing -> startLocal (Just file) numcopies key Nothing
diff --git a/Command/Find.hs b/Command/Find.hs
index c6a32a944..bcf83729a 100644
--- a/Command/Find.hs
+++ b/Command/Find.hs
@@ -39,8 +39,8 @@ seek ps = do
 	format <- getFormat
 	withFilesInGit (whenAnnexed $ start format) ps
 
-start :: Maybe Utility.Format.Format -> FilePath -> (Key, Backend) -> CommandStart
-start format file (key, _) = do
+start :: Maybe Utility.Format.Format -> FilePath -> Key -> CommandStart
+start format file key = do
 	-- only files inAnnex are shown, unless the user has requested
 	-- others via a limit
 	whenM (limited <||> inAnnex key) $
diff --git a/Command/Fix.hs b/Command/Fix.hs
index f730226e3..0c2bf5942 100644
--- a/Command/Fix.hs
+++ b/Command/Fix.hs
@@ -26,8 +26,8 @@ seek :: CommandSeek
 seek = withFilesInGit $ whenAnnexed start
 
 {- Fixes the symlink to an annexed file. -}
-start :: FilePath -> (Key, Backend) -> CommandStart
-start file (key, _) = do
+start :: FilePath -> Key -> CommandStart
+start file key = do
 	link <- inRepo $ gitAnnexLink file key
 	stopUnless ((/=) (Just link) <$> liftIO (catchMaybeIO $ readSymbolicLink file)) $ do
 		showStart "fix" file
diff --git a/Command/Fsck.hs b/Command/Fsck.hs
index 88a9915c4..a17662d62 100644
--- a/Command/Fsck.hs
+++ b/Command/Fsck.hs
@@ -104,12 +104,16 @@ getIncremental = do
 						resetStartTime
 		return True
 
-start :: Maybe Remote -> Incremental -> FilePath -> (Key, Backend) -> CommandStart
-start from inc file (key, backend) = do
-	numcopies <- getFileNumCopies file
-	case from of
-		Nothing -> go $ perform key file backend numcopies
-		Just r -> go $ performRemote key file backend numcopies r
+start :: Maybe Remote -> Incremental -> FilePath -> Key -> CommandStart
+start from inc file key = do
+	v <- Backend.getBackend file key
+	case v of
+		Nothing -> stop
+		Just backend -> do
+			numcopies <- getFileNumCopies file
+			case from of
+				Nothing -> go $ perform key file backend numcopies
+				Just r -> go $ performRemote key file backend numcopies r
   where
 	go = runFsck inc file key
 
diff --git a/Command/Get.hs b/Command/Get.hs
index bef466724..d0be20018 100644
--- a/Command/Get.hs
+++ b/Command/Get.hs
@@ -31,8 +31,8 @@ seek ps = do
 		(withFilesInGit $ whenAnnexed $ start from)
 		ps
 
-start :: Maybe Remote -> FilePath -> (Key, Backend) -> CommandStart
-start from file (key, _) = start' expensivecheck from key (Just file)
+start :: Maybe Remote -> FilePath -> Key -> CommandStart
+start from file key = start' expensivecheck from key (Just file)
   where
 	expensivecheck = checkAuto (numCopiesCheck file key (<) <||> wantGet False (Just key) (Just file))
 
diff --git a/Command/ImportFeed.hs b/Command/ImportFeed.hs
index 3f629af6e..80e59b739 100644
--- a/Command/ImportFeed.hs
+++ b/Command/ImportFeed.hs
@@ -194,7 +194,7 @@ performDownload relaxed cache todownload = case location todownload of
 				in d </> show n ++ "_" ++ base
 		tryanother = makeunique url (n + 1) file
 		alreadyexists = liftIO $ isJust <$> catchMaybeIO (getSymbolicLinkStatus f)
-		checksameurl (k, _) = ifM (elem url <$> getUrls k)
+		checksameurl k = ifM (elem url <$> getUrls k)
 			( return Nothing
 			, tryanother
 			)
diff --git a/Command/Indirect.hs b/Command/Indirect.hs
index c0dd57959..acf40c974 100644
--- a/Command/Indirect.hs
+++ b/Command/Indirect.hs
@@ -74,7 +74,7 @@ perform = do
 		case r of
 			Just s
 				| isSymbolicLink s -> void $ flip whenAnnexed f $
-					\_ (k, _) -> do
+					\_ k -> do
 						removeInodeCache k
 						removeAssociatedFiles k
 						return Nothing
diff --git a/Command/List.hs b/Command/List.hs
index 1fa206405..d038d6deb 100644
--- a/Command/List.hs
+++ b/Command/List.hs
@@ -60,8 +60,8 @@ getList = ifM (Annex.getFlag $ optionName allrepos)
 printHeader :: [(UUID, RemoteName, TrustLevel)] -> Annex ()
 printHeader l = liftIO $ putStrLn $ header $ map (\(_, n, t) -> (n, t)) l
 
-start :: [(UUID, RemoteName, TrustLevel)] -> FilePath -> (Key, Backend) -> CommandStart
-start l file (key, _) = do
+start :: [(UUID, RemoteName, TrustLevel)] -> FilePath -> Key -> CommandStart
+start l file key = do
 	ls <- S.fromList <$> keyLocations key
 	liftIO $ putStrLn $ format (map (\(u, _, t) -> (t, S.member u ls)) l) file
 	stop
diff --git a/Command/Log.hs b/Command/Log.hs
index 84583a93a..b0109f117 100644
--- a/Command/Log.hs
+++ b/Command/Log.hs
@@ -64,9 +64,15 @@ seek ps = do
 		Annex.getField (optionName o)
 	use o v = [Param ("--" ++ optionName o), Param v]
 
-start :: M.Map UUID String -> TimeZone -> [CommandParam] -> Bool ->
-	FilePath -> (Key, Backend) -> CommandStart
-start m zone os gource file (key, _) = do
+start
+	:: M.Map UUID String
+	-> TimeZone
+	-> [CommandParam]
+	-> Bool
+	-> FilePath
+	-> Key
+	-> CommandStart
+start m zone os gource file key = do
 	showLog output =<< readLog <$> getLog key os
 	-- getLog produces a zombie; reap it
 	liftIO reapZombies
diff --git a/Command/MetaData.hs b/Command/MetaData.hs
index d932315ab..38f9b8522 100644
--- a/Command/MetaData.hs
+++ b/Command/MetaData.hs
@@ -63,8 +63,8 @@ seek ps = do
 		(withFilesInGit (whenAnnexed $ start now getfield modmeta))
 		ps
 
-start :: POSIXTime -> Maybe MetaField -> [ModMeta] -> FilePath -> (Key, Backend) -> CommandStart
-start now f ms file (k, _) = start' (Just file) now f ms k
+start :: POSIXTime -> Maybe MetaField -> [ModMeta] -> FilePath -> Key -> CommandStart
+start now f ms file = start' (Just file) now f ms
 
 startKeys :: POSIXTime -> Maybe MetaField -> [ModMeta] -> Key -> CommandStart
 startKeys = start' Nothing
diff --git a/Command/Migrate.hs b/Command/Migrate.hs
index c14c07bdd..18e6e0748 100644
--- a/Command/Migrate.hs
+++ b/Command/Migrate.hs
@@ -25,15 +25,19 @@ def = [notDirect $
 seek :: CommandSeek
 seek = withFilesInGit $ whenAnnexed start
 
-start :: FilePath -> (Key, Backend) -> CommandStart
-start file (key, oldbackend) = do
-	exists <- inAnnex key
-	newbackend <- choosebackend =<< chooseBackend file
-	if (newbackend /= oldbackend || upgradableKey oldbackend key) && exists
-		then do
-			showStart "migrate" file
-			next $ perform file key oldbackend newbackend
-		else stop
+start :: FilePath -> Key -> CommandStart
+start file key = do
+	v <- Backend.getBackend file key
+	case v of
+		Nothing -> stop
+		Just oldbackend -> do
+			exists <- inAnnex key
+			newbackend <- choosebackend =<< chooseBackend file
+			if (newbackend /= oldbackend || upgradableKey oldbackend key) && exists
+				then do
+					showStart "migrate" file
+					next $ perform file key oldbackend newbackend
+				else stop
   where
 	choosebackend Nothing = Prelude.head <$> orderedList
 	choosebackend (Just backend) = return backend
diff --git a/Command/Mirror.hs b/Command/Mirror.hs
index 4a7a8dd99..4e9a85009 100644
--- a/Command/Mirror.hs
+++ b/Command/Mirror.hs
@@ -31,8 +31,8 @@ seek ps = do
 		(withFilesInGit $ whenAnnexed $ start to from)
 		ps
 
-start :: Maybe Remote -> Maybe Remote -> FilePath -> (Key, Backend) -> CommandStart
-start to from file (key, _backend) = startKey to from (Just file) key
+start :: Maybe Remote -> Maybe Remote -> FilePath -> Key -> CommandStart
+start to from file key = startKey to from (Just file) key
 
 startKey :: Maybe Remote -> Maybe Remote -> Maybe FilePath -> Key -> CommandStart
 startKey to from afile key = do
diff --git a/Command/Move.hs b/Command/Move.hs
index 206a875b7..396ea4afc 100644
--- a/Command/Move.hs
+++ b/Command/Move.hs
@@ -33,8 +33,8 @@ seek ps = do
 		(withFilesInGit $ whenAnnexed $ start to from True)
 		ps
 
-start :: Maybe Remote -> Maybe Remote -> Bool -> FilePath -> (Key, Backend) -> CommandStart
-start to from move file (key, _) = start' to from move (Just file) key
+start :: Maybe Remote -> Maybe Remote -> Bool -> FilePath -> Key -> CommandStart
+start to from move file key = start' to from move (Just file) key
 
 startKey :: Maybe Remote -> Maybe Remote -> Bool -> Key -> CommandStart
 startKey to from move = start' to from move Nothing
diff --git a/Command/ReKey.hs b/Command/ReKey.hs
index 805300f9f..2919a09e9 100644
--- a/Command/ReKey.hs
+++ b/Command/ReKey.hs
@@ -29,7 +29,7 @@ start :: (FilePath, String) -> CommandStart
 start (file, keyname) = ifAnnexed file go stop
   where
 	newkey = fromMaybe (error "bad key") $ file2key keyname
-	go (oldkey, _)
+	go oldkey
 		| oldkey == newkey = stop
 		| otherwise = do
 			showStart "rekey" file
diff --git a/Command/Reinject.hs b/Command/Reinject.hs
index 1609c6097..a516fe93c 100644
--- a/Command/Reinject.hs
+++ b/Command/Reinject.hs
@@ -12,6 +12,7 @@ import Command
 import Logs.Location
 import Annex.Content
 import qualified Command.Fsck
+import qualified Backend
 
 def :: [Command]
 def = [command "reinject" (paramPair "SRC" "DEST") seek
@@ -33,16 +34,20 @@ start (src:dest:[])
 		next $ whenAnnexed (perform src) dest
 start _ = error "specify a src file and a dest file"
 
-perform :: FilePath -> FilePath -> (Key, Backend) -> CommandPerform
-perform src _dest (key, backend) =
+perform :: FilePath -> FilePath -> Key -> CommandPerform
+perform src dest key = do
 	{- Check the content before accepting it. -}
-	ifM (Command.Fsck.checkKeySizeOr reject key src
-		<&&> Command.Fsck.checkBackendOr reject backend key src)
-		( do
-			unlessM move $ error "mv failed!"
-			next $ cleanup key
-		, error "not reinjecting"
-		)
+	v <- Backend.getBackend dest key
+	case v of
+		Nothing -> stop
+		Just backend ->
+			ifM (Command.Fsck.checkKeySizeOr reject key src
+				<&&> Command.Fsck.checkBackendOr reject backend key src)
+				( do
+					unlessM move $ error "mv failed!"
+					next $ cleanup key
+				, error "not reinjecting"
+				)
   where
 	-- the file might be on a different filesystem,
 	-- so mv is used rather than simply calling
diff --git a/Command/RmUrl.hs b/Command/RmUrl.hs
index 3f304b76e..e961575a3 100644
--- a/Command/RmUrl.hs
+++ b/Command/RmUrl.hs
@@ -20,7 +20,7 @@ seek :: CommandSeek
 seek = withPairs start
 
 start :: (FilePath, String) -> CommandStart
-start (file, url) = flip whenAnnexed file $ \_ (key, _) -> do
+start (file, url) = flip whenAnnexed file $ \_ key -> do
 	showStart "rmurl" file
 	next $ next $ cleanup url key
 
diff --git a/Command/Sync.hs b/Command/Sync.hs
index dfcb0d22a..a5d6d46f1 100644
--- a/Command/Sync.hs
+++ b/Command/Sync.hs
@@ -338,8 +338,8 @@ seekSyncContent rs = do
 		(\v -> void (liftIO (tryPutMVar mvar ())) >> syncFile rs f v)
 		noop
 
-syncFile :: [Remote] -> FilePath -> (Key, Backend) -> Annex ()
-syncFile rs f (k, _) = do
+syncFile :: [Remote] -> FilePath -> Key -> Annex ()
+syncFile rs f k = do
 	locs <- loggedLocations k
 	let (have, lack) = partition (\r -> Remote.uuid r `elem` locs) rs
 
diff --git a/Command/Unannex.hs b/Command/Unannex.hs
index ca9788ddb..daa14ce85 100644
--- a/Command/Unannex.hs
+++ b/Command/Unannex.hs
@@ -58,8 +58,8 @@ wrapUnannex a = ifM isDirect
 			then void (liftIO cleanup) >> return True
 			else void (liftIO cleanup) >> return False
 
-start :: FilePath -> (Key, Backend) -> CommandStart
-start file (key, _) = stopUnless (inAnnex key) $ do
+start :: FilePath -> Key -> CommandStart
+start file key = stopUnless (inAnnex key) $ do
 	showStart "unannex" file
 	next $ ifM isDirect
 		( performDirect file key
diff --git a/Command/Uninit.hs b/Command/Uninit.hs
index dccf4a614..0f0628156 100644
--- a/Command/Uninit.hs
+++ b/Command/Uninit.hs
@@ -44,7 +44,7 @@ seek ps = do
 
 {- git annex symlinks that are not checked into git could be left by an
  - interrupted add. -}
-startCheckIncomplete :: FilePath -> (Key, Backend) -> CommandStart
+startCheckIncomplete :: FilePath -> Key -> CommandStart
 startCheckIncomplete file _ = error $ unlines
 	[ file ++ " points to annexed content, but is not checked into git."
 	, "Perhaps this was left behind by an interrupted git annex add?"
diff --git a/Command/Unlock.hs b/Command/Unlock.hs
index 4cfe39307..0070410a6 100644
--- a/Command/Unlock.hs
+++ b/Command/Unlock.hs
@@ -25,8 +25,8 @@ seek = withFilesInGit $ whenAnnexed start
 
 {- The unlock subcommand replaces the symlink with a copy of the file's
  - content. -}
-start :: FilePath -> (Key, Backend) -> CommandStart
-start file (key, _) = do
+start :: FilePath -> Key -> CommandStart
+start file key = do
 	showStart "unlock" file
 	next $ perform file key
 
diff --git a/Command/Unused.hs b/Command/Unused.hs
index 3e844e5a8..5815bbf29 100644
--- a/Command/Unused.hs
+++ b/Command/Unused.hs
@@ -250,7 +250,7 @@ withKeysReferenced' mdir initial a = do
 		x <- Backend.lookupFile f
 		case x of
 			Nothing -> go v fs
-			Just (k, _) -> do
+			Just k -> do
 				!v' <- a k f v
 				go v' fs
 
@@ -294,7 +294,7 @@ withKeysReferencedInGitRef a ref = do
 	forM_ ts $ tKey lookAtWorkingTree >=> maybe noop a
 	liftIO $ void clean
   where
-	tKey True = fmap fst <$$> Backend.lookupFile . getTopFilePath . DiffTree.file
+	tKey True = Backend.lookupFile . getTopFilePath . DiffTree.file
 	tKey False = fileKey . takeFileName . decodeBS <$$>
 		catFile ref . getTopFilePath . DiffTree.file
 
diff --git a/Command/Whereis.hs b/Command/Whereis.hs
index 387ffebc9..d2c27eb9b 100644
--- a/Command/Whereis.hs
+++ b/Command/Whereis.hs
@@ -27,8 +27,8 @@ seek ps = do
 		(withFilesInGit $ whenAnnexed $ start m)
 		ps
 
-start :: M.Map UUID Remote -> FilePath -> (Key, Backend) -> CommandStart
-start remotemap file (key, _) = start' remotemap key (Just file)
+start :: M.Map UUID Remote -> FilePath -> Key -> CommandStart
+start remotemap file key = start' remotemap key (Just file)
 
 startKeys :: M.Map UUID Remote -> Key -> CommandStart
 startKeys remotemap key = start' remotemap key Nothing
diff --git a/Limit.hs b/Limit.hs
index b46ff1a06..9ac849bce 100644
--- a/Limit.hs
+++ b/Limit.hs
@@ -234,10 +234,10 @@ limitSize vs s = case readSize dataUnits s of
 	Nothing -> Left "bad size"
 	Just sz -> Right $ go sz
   where
-  	go sz _ (MatchingFile fi) = lookupFile fi >>= check fi sz
+  	go sz _ (MatchingFile fi) = lookupFileKey fi >>= check fi sz
 	go sz _ (MatchingKey key) = checkkey sz key
 	checkkey sz key = return $ keySize key `vs` Just sz
-	check _ sz (Just (key, _)) = checkkey sz key
+	check _ sz (Just key) = checkkey sz key
 	check fi sz Nothing = do
 		filesize <- liftIO $ catchMaybeIO $
 			fromIntegral . fileSize
@@ -272,11 +272,8 @@ addTimeLimit s = do
 				liftIO $ exitWith $ ExitFailure 101
 			else return True
 
-lookupFile :: FileInfo -> Annex (Maybe (Key, Backend))
-lookupFile = Backend.lookupFile . relFile
-
 lookupFileKey :: FileInfo -> Annex (Maybe Key)
-lookupFileKey = (fst <$>) <$$> Backend.lookupFile . relFile
+lookupFileKey = Backend.lookupFile . relFile
 
 checkKey :: (Key -> Annex Bool) -> MatchInfo -> Annex Bool
 checkKey a (MatchingFile fi) = lookupFileKey fi >>= maybe (return False) a
diff --git a/Test.hs b/Test.hs
index afcd5790e..55546d08b 100644
--- a/Test.hs
+++ b/Test.hs
@@ -712,7 +712,7 @@ test_unused env = intmpclonerepoInDirect env $ do
 			(sort expectedkeys) (sort unusedkeys)
 	findkey f = do
 		r <- Backend.lookupFile f
-		return $ fst $ fromJust r
+		return $ fromJust r
 
 test_describe :: TestEnv -> Assertion
 test_describe env = intmpclonerepo env $ do
@@ -1233,7 +1233,7 @@ test_crypto env = do
 			(c,k) <- annexeval $ do
 				uuid <- Remote.nameToUUID "foo"
 				rs <- Logs.Remote.readRemoteLog
-				Just (k,_) <- Backend.lookupFile annexedfile
+				Just k <- Backend.lookupFile annexedfile
 				return (fromJust $ M.lookup uuid rs, k)
 			let key = if scheme `elem` ["hybrid","pubkey"]
 					then Just $ Utility.Gpg.KeyIds [Utility.Gpg.testKeyId]
@@ -1500,7 +1500,7 @@ checklocationlog f expected = do
 	thisuuid <- annexeval Annex.UUID.getUUID
 	r <- annexeval $ Backend.lookupFile f
 	case r of
-		Just (k, _) -> do
+		Just k -> do
 			uuids <- annexeval $ Remote.keyLocations k
 			assertEqual ("bad content in location log for " ++ f ++ " key " ++ Types.Key.key2file k ++ " uuid " ++ show thisuuid)
 				expected (thisuuid `elem` uuids)
@@ -1508,9 +1508,9 @@ checklocationlog f expected = do
 
 checkbackend :: FilePath -> Types.Backend -> Assertion
 checkbackend file expected = do
-	r <- annexeval $ Backend.lookupFile file
-	let b = snd $ fromJust r
-	assertEqual ("backend for " ++ file) expected b
+	b <- annexeval $ maybe (return Nothing) (Backend.getBackend file) 
+		=<< Backend.lookupFile file
+	assertEqual ("backend for " ++ file) (Just expected) b
 
 inlocationlog :: FilePath -> Assertion
 inlocationlog f = checklocationlog f True