diff --git a/Annex.hs b/Annex.hs
index 4d3786cc9b..cc2f8b1607 100644
--- a/Annex.hs
+++ b/Annex.hs
@@ -401,7 +401,7 @@ adjustGitRepo a = do
 addGitConfigOverride :: String -> Annex ()
 addGitConfigOverride v = do
 	adjustGitRepo $ \r ->
-		Git.Config.store (encodeBS' v) Git.Config.ConfigList $
+		Git.Config.store (encodeBS v) Git.Config.ConfigList $
 			r { Git.gitGlobalOpts = go (Git.gitGlobalOpts r) }
 	changeState $ \st -> st { gitconfigoverride = v : gitconfigoverride st }
   where
diff --git a/Annex/MetaData.hs b/Annex/MetaData.hs
index e821101c0a..a21cdd601f 100644
--- a/Annex/MetaData.hs
+++ b/Annex/MetaData.hs
@@ -72,11 +72,11 @@ genMetaData key file status = do
  - only changes to add the date fields. -}
 dateMetaData :: UTCTime -> MetaData -> MetaData
 dateMetaData mtime old = modMeta old $
-	(SetMeta yearMetaField $ S.singleton $ toMetaValue $ encodeBS' $ show y)
+	(SetMeta yearMetaField $ S.singleton $ toMetaValue $ encodeBS $ show y)
 		`ComposeModMeta`
-	(SetMeta monthMetaField $ S.singleton $ toMetaValue $ encodeBS' $ show m)
+	(SetMeta monthMetaField $ S.singleton $ toMetaValue $ encodeBS $ show m)
 		`ComposeModMeta`
-	(SetMeta dayMetaField $ S.singleton $ toMetaValue $ encodeBS' $ show d)
+	(SetMeta dayMetaField $ S.singleton $ toMetaValue $ encodeBS $ show d)
   where
 	(y, m, d) = toGregorian $ utctDay mtime
 
diff --git a/Annex/UUID.hs b/Annex/UUID.hs
index e85062e438..872fb9091a 100644
--- a/Annex/UUID.hs
+++ b/Annex/UUID.hs
@@ -110,7 +110,7 @@ storeUUIDIn configfield = setConfig configfield . fromUUID
 {- Only sets the configkey in the Repo; does not change .git/config -}
 setUUID :: Git.Repo -> UUID -> IO Git.Repo
 setUUID r u = do
-	let s = encodeBS' $ show configkeyUUID ++ "=" ++ fromUUID u
+	let s = encodeBS $ show configkeyUUID ++ "=" ++ fromUUID u
 	Git.Config.store s Git.Config.ConfigList r
 
 -- Dummy uuid for the whole web. Do not alter.
diff --git a/Assistant/Threads/Merger.hs b/Assistant/Threads/Merger.hs
index 04d1a135b2..a7897086a8 100644
--- a/Assistant/Threads/Merger.hs
+++ b/Assistant/Threads/Merger.hs
@@ -118,6 +118,6 @@ isAnnexBranch f = n `isSuffixOf` f
 	n = '/' : Git.fromRef Annex.Branch.name
 
 fileToBranch :: FilePath -> Git.Ref
-fileToBranch f = Git.Ref $ encodeBS' $ "refs" </> base
+fileToBranch f = Git.Ref $ encodeBS $ "refs" </> base
   where
 	base = Prelude.last $ split "/refs/" f
diff --git a/Assistant/Threads/Watcher.hs b/Assistant/Threads/Watcher.hs
index 72ff1233a4..b1346a9723 100644
--- a/Assistant/Threads/Watcher.hs
+++ b/Assistant/Threads/Watcher.hs
@@ -321,7 +321,7 @@ addLink :: FilePath -> LinkTarget -> Maybe Key -> Assistant (Maybe Change)
 addLink file link mk = do
 	debug ["add symlink", file]
 	liftAnnex $ do
-		v <- catObjectDetails $ Ref $ encodeBS' $ ':':file
+		v <- catObjectDetails $ Ref $ encodeBS $ ':':file
 		case v of
 			Just (currlink, sha, _type)
 				| L.fromStrict link == currlink ->
diff --git a/Assistant/WebApp/Configurators/Edit.hs b/Assistant/WebApp/Configurators/Edit.hs
index 14856e5aa7..c430697097 100644
--- a/Assistant/WebApp/Configurators/Edit.hs
+++ b/Assistant/WebApp/Configurators/Edit.hs
@@ -102,7 +102,7 @@ setRepoConfig uuid mremote oldc newc = do
 			 - there's not. Special remotes don't normally
 			 - have that, and don't use it. Temporarily add
 			 - it if it's missing. -}
-			let remotefetch = Git.ConfigKey $ encodeBS' $
+			let remotefetch = Git.ConfigKey $ encodeBS $
 				"remote." ++ T.unpack (repoName oldc) ++ ".fetch"
 			needfetch <- isNothing <$> fromRepo (Git.Config.getMaybe remotefetch)
 			when needfetch $
diff --git a/Backend/External.hs b/Backend/External.hs
index bd4ac5ef05..c353e049c7 100644
--- a/Backend/External.hs
+++ b/Backend/External.hs
@@ -239,7 +239,7 @@ newExternalState ebname hasext pid = do
 		warning msg
 
 externalBackendProgram :: ExternalBackendName -> String
-externalBackendProgram (ExternalBackendName bname) = "git-annex-backend-X" ++ decodeBS' bname
+externalBackendProgram (ExternalBackendName bname) = "git-annex-backend-X" ++ decodeBS bname
 
 -- Runs an action with an ExternalState, starting a new external backend
 -- process if necessary. It is returned to the pool once the action
diff --git a/Backend/Utilities.hs b/Backend/Utilities.hs
index ad9b142ab9..7121d4f2f5 100644
--- a/Backend/Utilities.hs
+++ b/Backend/Utilities.hs
@@ -28,10 +28,10 @@ import Data.Word
 genKeyName :: String -> S.ByteString
 genKeyName s
 	-- Avoid making keys longer than the length of a SHA256 checksum.
-	| bytelen > sha256len = encodeBS' $
+	| bytelen > sha256len = encodeBS $
 		truncateFilePath (sha256len - md5len - 1) s' ++ "-" ++ 
 			show (md5 bl)
-	| otherwise = encodeBS' s'
+	| otherwise = encodeBS s'
   where
 	s' = preSanitizeKeyName s
 	bl = encodeBL s
diff --git a/CmdLine/Option.hs b/CmdLine/Option.hs
index 8f31060112..bf54189c5d 100644
--- a/CmdLine/Option.hs
+++ b/CmdLine/Option.hs
@@ -79,7 +79,7 @@ commonGlobalOptions =
 		-- Also set in git config so it will be passed on to any
 		-- git-annex child processes.
 		, setAnnexState $ Annex.addGitConfigOverride $
-			decodeBS' $ debugconfig <> "=" <> boolConfig' v
+			decodeBS $ debugconfig <> "=" <> boolConfig' v
 		]
 	
 	setdebugfilter v = mconcat
@@ -88,7 +88,7 @@ commonGlobalOptions =
 		-- Also set in git config so it will be passed on to any
 		-- git-annex child processes.
 		, setAnnexState $ Annex.addGitConfigOverride $ 
-			decodeBS' (debugfilterconfig <> "=") ++ v
+			decodeBS (debugfilterconfig <> "=") ++ v
 		]
 	
 	(ConfigKey debugconfig) = annexConfig "debug"
diff --git a/Command/Config.hs b/Command/Config.hs
index 4a408ab742..9313ea1b5c 100644
--- a/Command/Config.hs
+++ b/Command/Config.hs
@@ -55,23 +55,23 @@ optParser _ = setconfig <|> getconfig <|> unsetconfig
 
 seek :: Action -> CommandSeek
 seek (SetConfig ck@(ConfigKey name) val) = checkIsGlobalConfig ck $ commandAction $
-	startingUsualMessages (decodeBS' name) ai si $ do
+	startingUsualMessages (decodeBS name) ai si $ do
 		setGlobalConfig ck val
 		when (needLocalUpdate ck) $
 			setConfig ck (fromConfigValue val)
 		next $ return True
   where
 	ai = ActionItemOther (Just (fromConfigValue val))
-	si = SeekInput [decodeBS' name]
+	si = SeekInput [decodeBS name]
 seek (UnsetConfig ck@(ConfigKey name)) = checkIsGlobalConfig ck $ commandAction $
-	startingUsualMessages (decodeBS' name) ai si $ do
+	startingUsualMessages (decodeBS name) ai si $ do
 		unsetGlobalConfig ck
 		when (needLocalUpdate ck) $
 			unsetConfig ck
 		next $ return True
   where
 	ai = ActionItemOther (Just "unset")
-	si = SeekInput [decodeBS' name]
+	si = SeekInput [decodeBS name]
 seek (GetConfig ck) = checkIsGlobalConfig ck $ commandAction $
 	startingCustomOutput ai $ do
 		getGlobalConfig ck >>= \case
diff --git a/Command/DiffDriver.hs b/Command/DiffDriver.hs
index 9dc8c5b26b..9b1e3ec512 100644
--- a/Command/DiffDriver.hs
+++ b/Command/DiffDriver.hs
@@ -89,7 +89,7 @@ fixupReq req@(Req {}) =
 	check rOldFile rOldMode (\r f -> r { rOldFile = f }) req
 		>>= check rNewFile rNewMode (\r f -> r { rNewFile = f })
   where
-	check getfile getmode setfile r = case readTreeItemType (encodeBS' (getmode r)) of
+	check getfile getmode setfile r = case readTreeItemType (encodeBS (getmode r)) of
 		Just TreeSymlink -> do
 			v <- getAnnexLinkTarget' f False
 			maybe (return r) repoint (parseLinkTargetOrPointer =<< v)
diff --git a/Command/FindRef.hs b/Command/FindRef.hs
index 27dfcbe07a..f332923309 100644
--- a/Command/FindRef.hs
+++ b/Command/FindRef.hs
@@ -22,6 +22,6 @@ seek o = Find.seek o'
   where
 	o' = o 
 		{ Find.keyOptions = Just $ WantBranchKeys $
-			map (Git.Ref . encodeBS') (Find.findThese o)
+			map (Git.Ref . encodeBS) (Find.findThese o)
 		, Find.findThese = []
 		}
diff --git a/Command/Fsck.hs b/Command/Fsck.hs
index 1e2ea3801c..5ab724362f 100644
--- a/Command/Fsck.hs
+++ b/Command/Fsck.hs
@@ -292,7 +292,7 @@ verifyLocationLog' key ai present u updatestatus = do
 			fix InfoMissing
 			warning $
 				"** Based on the location log, " ++
-				decodeBS' (actionItemDesc ai) ++
+				decodeBS (actionItemDesc ai) ++
 				"\n** was expected to be present, " ++
 				"but its content is missing."
 			return False
@@ -332,7 +332,7 @@ verifyRequiredContent key ai@(ActionItemAssociatedFile afile _) = case afile of
 				missingrequired <- Remote.prettyPrintUUIDs "missingrequired" missinglocs
 				warning $
 					"** Required content " ++
-					decodeBS' (actionItemDesc ai) ++
+					decodeBS (actionItemDesc ai) ++
 					" is missing from these repositories:\n" ++
 					missingrequired
 				return False
@@ -406,7 +406,7 @@ checkKeySizeOr bad key file ai = case fromKey keySize key of
 	badsize a b = do
 		msg <- bad key
 		warning $ concat
-			[ decodeBS' (actionItemDesc ai)
+			[ decodeBS (actionItemDesc ai)
 			, ": Bad file size ("
 			, compareSizes storageUnits True a b
 			, "); "
@@ -424,11 +424,11 @@ checkKeyUpgrade backend key ai (AssociatedFile (Just file)) =
 	case Types.Backend.canUpgradeKey backend of
 		Just a | a key -> do
 			warning $ concat
-				[ decodeBS' (actionItemDesc ai)
+				[ decodeBS (actionItemDesc ai)
 				, ": Can be upgraded to an improved key format. "
 				, "You can do so by running: git annex migrate --backend="
 				, decodeBS (formatKeyVariety (fromKey keyVariety key)) ++ " "
-				, decodeBS' file
+				, decodeBS file
 				]
 			return True
 		_ -> return True
@@ -475,7 +475,7 @@ checkBackendOr bad backend key file ai =
 			unless ok $ do
 				msg <- bad key
 				warning $ concat
-					[ decodeBS' (actionItemDesc ai)
+					[ decodeBS (actionItemDesc ai)
 					, ": Bad file content; "
 					, msg
 					]
@@ -503,7 +503,7 @@ checkInodeCache key content mic ai = case mic of
 					Nothing -> noop
 					Just ic' -> whenM (compareInodeCaches ic ic') $ do
 						warning $ concat
-							[ decodeBS' (actionItemDesc ai)
+							[ decodeBS (actionItemDesc ai)
 							, ": Stale or missing inode cache; updating."
 							]
 						Database.Keys.addInodeCaches key [ic]
diff --git a/Command/Import.hs b/Command/Import.hs
index d133d0f306..b0a1b0898a 100644
--- a/Command/Import.hs
+++ b/Command/Import.hs
@@ -85,7 +85,7 @@ optParser desc = do
 			[bs] -> 
 				let (branch, subdir) = separate (== ':') bs
 				in RemoteImportOptions r
-					(Ref (encodeBS' branch))
+					(Ref (encodeBS branch))
 					(if null subdir then Nothing else Just subdir)
 					content
 					ic
diff --git a/Command/Info.hs b/Command/Info.hs
index 36c7a88cb9..2d97603e9b 100644
--- a/Command/Info.hs
+++ b/Command/Info.hs
@@ -163,7 +163,7 @@ itemInfo o (si, p) = ifM (isdir p)
 
 noInfo :: String -> SeekInput -> Annex ()
 noInfo s si = do
-	showStart "info" (encodeBS' s) si
+	showStart "info" (encodeBS s) si
 	showNote $ "not a directory or an annexed file or a treeish or a remote or a uuid"
 	showEndFail
 
@@ -183,7 +183,7 @@ dirInfo o dir si = showCustom (unwords ["info", dir]) si $ do
 
 treeishInfo :: InfoOptions -> String -> SeekInput -> Annex ()
 treeishInfo o t si = do
-	mi <- getTreeStatInfo o (Git.Ref (encodeBS' t))
+	mi <- getTreeStatInfo o (Git.Ref (encodeBS t))
 	case mi of
 		Nothing -> noInfo t si
 		Just i -> showCustom (unwords ["info", t]) si $ do
@@ -313,8 +313,8 @@ showStat :: Stat -> StatState ()
 showStat s = maybe noop calc =<< s
   where
 	calc (desc, a) = do
-		(lift . showHeader . encodeBS') desc
-		lift . showRaw . encodeBS' =<< a
+		(lift . showHeader . encodeBS) desc
+		lift . showRaw . encodeBS =<< a
 
 repo_list :: TrustLevel -> Stat
 repo_list level = stat n $ nojson $ lift $ do
diff --git a/Command/Log.hs b/Command/Log.hs
index b46749d9ba..b4d99b5f72 100644
--- a/Command/Log.hs
+++ b/Command/Log.hs
@@ -230,7 +230,7 @@ getGitLog fs os = do
 		[ Param $ Git.fromRef Annex.Branch.fullname
 		, Param "--"
 		] ++ map Param fs
-	return (parseGitRawLog config (map decodeBL' ls), cleanup)
+	return (parseGitRawLog config (map decodeBL ls), cleanup)
 
 -- Parses chunked git log --raw output, which looks something like:
 --
diff --git a/Command/Merge.hs b/Command/Merge.hs
index e7523f6252..ad5dce3453 100644
--- a/Command/Merge.hs
+++ b/Command/Merge.hs
@@ -39,7 +39,7 @@ seek o
 	| otherwise = do
 		prepMerge
 		forM_ (mergeBranches o) $
-			commandAction . mergeBranch o . Git.Ref . encodeBS'
+			commandAction . mergeBranch o . Git.Ref . encodeBS
 
 mergeAnnexBranch :: CommandStart
 mergeAnnexBranch = starting "merge" ai si $ do
diff --git a/Command/Uninit.hs b/Command/Uninit.hs
index ac206594ed..473040c2c4 100644
--- a/Command/Uninit.hs
+++ b/Command/Uninit.hs
@@ -37,7 +37,7 @@ check = do
 	whenM ((/=) <$> liftIO (absPath top) <*> liftIO (absPath currdir)) $
 		giveup "can only run uninit from the top of the git repository"
   where
-	current_branch = Git.Ref . encodeBS' . Prelude.head . lines . decodeBS' <$> revhead
+	current_branch = Git.Ref . encodeBS . Prelude.head . lines . decodeBS <$> revhead
 	revhead = inRepo $ Git.Command.pipeReadStrict
 		[Param "rev-parse", Param "--abbrev-ref", Param "HEAD"]
 
diff --git a/Command/Vicfg.hs b/Command/Vicfg.hs
index 443570eb85..323ed22241 100644
--- a/Command/Vicfg.hs
+++ b/Command/Vicfg.hs
@@ -311,7 +311,7 @@ parseCfg defcfg = go [] defcfg . lines
 				let m = M.insert u l (cfgScheduleMap cfg)
 				in Right $ cfg { cfgScheduleMap = m }
 		| setting == "config" =
-			let m = M.insert (ConfigKey (encodeBS' f)) (ConfigValue (encodeBS' val)) (cfgGlobalConfigs cfg)
+			let m = M.insert (ConfigKey (encodeBS f)) (ConfigValue (encodeBS val)) (cfgGlobalConfigs cfg)
 			in Right $ cfg { cfgGlobalConfigs = m }
 		| setting == "numcopies" = case readish val of
 			Nothing -> Left "parse error (expected an integer)"
diff --git a/Config.hs b/Config.hs
index 5dd65cdff3..0af6810e31 100644
--- a/Config.hs
+++ b/Config.hs
@@ -39,7 +39,7 @@ setConfig :: ConfigKey -> String -> Annex ()
 setConfig (ConfigKey key) value = do
 	inRepo $ Git.Command.run
 		[ Param "config"
-		, Param (decodeBS' key)
+		, Param (decodeBS key)
 		, Param value
 		]
 	reloadConfig
diff --git a/Database/Types.hs b/Database/Types.hs
index 561972284a..7b317ce6ac 100644
--- a/Database/Types.hs
+++ b/Database/Types.hs
@@ -95,10 +95,10 @@ newtype SSha = SSha String
 	deriving (Eq, Show)
 
 toSSha :: Sha -> SSha
-toSSha (Ref s) = SSha (decodeBS' s)
+toSSha (Ref s) = SSha (decodeBS s)
 
 fromSSha :: SSha -> Ref
-fromSSha (SSha s) = Ref (encodeBS' s)
+fromSSha (SSha s) = Ref (encodeBS s)
 
 instance PersistField SSha where
 	toPersistValue (SSha b) = toPersistValue b
diff --git a/Git/Config.hs b/Git/Config.hs
index 20ddf790d8..7b3678aaa7 100644
--- a/Git/Config.hs
+++ b/Git/Config.hs
@@ -170,7 +170,7 @@ parse s st
 
 {- Checks if a string from git config is a true/false value. -}
 isTrueFalse :: String -> Maybe Bool
-isTrueFalse = isTrueFalse' . ConfigValue . encodeBS'
+isTrueFalse = isTrueFalse' . ConfigValue . encodeBS
 
 isTrueFalse' :: ConfigValue -> Maybe Bool
 isTrueFalse' (ConfigValue s)
@@ -248,8 +248,8 @@ changeFile f (ConfigKey k) v = boolSystem "git"
 	[ Param "config"
 	, Param "--file"
 	, File f
-	, Param (decodeBS' k)
-	, Param (decodeBS' v)
+	, Param (decodeBS k)
+	, Param (decodeBS v)
 	]
 
 {- Unsets a git config setting, in both the git repo,
@@ -264,4 +264,4 @@ unset ck@(ConfigKey k) r = ifM (Git.Command.runBool ps r)
 	, return Nothing
 	)
   where
-	ps = [Param "config", Param "--unset-all", Param (decodeBS' k)]
+	ps = [Param "config", Param "--unset-all", Param (decodeBS k)]
diff --git a/Git/ConfigTypes.hs b/Git/ConfigTypes.hs
index 1f8f9455b3..3ec43be6a5 100644
--- a/Git/ConfigTypes.hs
+++ b/Git/ConfigTypes.hs
@@ -31,7 +31,7 @@ getSharedRepository r =
 			"all" -> AllShared
 			"world" -> AllShared
 			"everybody" -> AllShared
-			_ -> maybe UnShared UmaskShared (readish (decodeBS' v))
+			_ -> maybe UnShared UmaskShared (readish (decodeBS v))
 		Just NoConfigValue -> UnShared
 		Nothing -> UnShared
 
diff --git a/Git/DiffTree.hs b/Git/DiffTree.hs
index 273b9427e0..fde223ddf3 100644
--- a/Git/DiffTree.hs
+++ b/Git/DiffTree.hs
@@ -114,7 +114,7 @@ parseDiffRaw l = go l
 	go (info:f:rest) = case A.parse (parserDiffRaw (L.toStrict f)) info of
 		A.Done _ r -> r : go rest
 		A.Fail _ _ err -> error $ "diff-tree parse error: " ++ err
-	go (s:[]) = error $ "diff-tree parse error near \"" ++ decodeBL' s ++ "\""
+	go (s:[]) = error $ "diff-tree parse error near \"" ++ decodeBL s ++ "\""
 
 -- :<srcmode> SP <dstmode> SP <srcsha> SP <dstsha> SP <status>
 --
diff --git a/Git/Fsck.hs b/Git/Fsck.hs
index de11e89af4..4544c1312f 100644
--- a/Git/Fsck.hs
+++ b/Git/Fsck.hs
@@ -159,7 +159,7 @@ isMissing s r = either (const True) (const False) <$> tryIO dump
 		] r
 
 findShas :: [String] -> [Sha]
-findShas = catMaybes . map (extractSha . encodeBS') 
+findShas = catMaybes . map (extractSha . encodeBS) 
 	. concat . map words . filter wanted
   where
 	wanted l = not ("dangling " `isPrefixOf` l)
diff --git a/Git/GCrypt.hs b/Git/GCrypt.hs
index c6a83313ef..c7e5df47f0 100644
--- a/Git/GCrypt.hs
+++ b/Git/GCrypt.hs
@@ -107,7 +107,7 @@ getParticiantList globalconfigrepo repo remotename = KeyIds $ parse $ firstJust
   where
 	defaultkey = "gcrypt.participants"
 	parse (Just (ConfigValue "simple")) = []
-	parse (Just (ConfigValue b)) = words (decodeBS' b)
+	parse (Just (ConfigValue b)) = words (decodeBS b)
 	parse (Just NoConfigValue) = []
 	parse Nothing = []
 
@@ -122,4 +122,4 @@ remoteSigningKey = remoteConfigKey "gcrypt-signingkey"
 
 remoteConfigKey :: S.ByteString -> RemoteName -> ConfigKey
 remoteConfigKey key remotename = ConfigKey $
-	"remote." <> encodeBS' remotename <> "." <> key
+	"remote." <> encodeBS remotename <> "." <> key
diff --git a/Git/LsFiles.hs b/Git/LsFiles.hs
index 297c068284..aff408deb6 100644
--- a/Git/LsFiles.hs
+++ b/Git/LsFiles.hs
@@ -251,7 +251,7 @@ data Unmerged = Unmerged
 unmerged :: [RawFilePath] -> Repo -> IO ([Unmerged], IO Bool)
 unmerged l repo = guardSafeForLsFiles repo $ do
 	(fs, cleanup) <- pipeNullSplit params repo
-	return (reduceUnmerged [] $ catMaybes $ map (parseUnmerged . decodeBL') fs, cleanup)
+	return (reduceUnmerged [] $ catMaybes $ map (parseUnmerged . decodeBL) fs, cleanup)
   where
 	params = 
 		Param "ls-files" :
@@ -277,7 +277,7 @@ parseUnmerged s
 				then Nothing
 				else do
 					treeitemtype <- readTreeItemType (encodeBS rawtreeitemtype)
-					sha <- extractSha (encodeBS' rawsha)
+					sha <- extractSha (encodeBS rawsha)
 					return $ InternalUnmerged (stage == 2) (toRawFilePath file)
 						(Just treeitemtype) (Just sha)
 		_ -> Nothing
diff --git a/Git/LsTree.hs b/Git/LsTree.hs
index a49c4eaa78..fb3b3e171b 100644
--- a/Git/LsTree.hs
+++ b/Git/LsTree.hs
@@ -149,7 +149,7 @@ parserLsTree long = case long of
  - generated, so any size information is not included. -}
 formatLsTree :: TreeItem -> S.ByteString
 formatLsTree ti = S.intercalate (S.singleton (fromIntegral (ord ' ')))
-	[ encodeBS' (showOct (mode ti) "")
+	[ encodeBS (showOct (mode ti) "")
 	, typeobj ti
 	, fromRef' (sha ti)
 	] <> (S.cons (fromIntegral (ord '\t')) (getTopFilePath (file ti)))
diff --git a/Git/Ref.hs b/Git/Ref.hs
index 6929a8ee91..a26e32fb49 100644
--- a/Git/Ref.hs
+++ b/Git/Ref.hs
@@ -82,7 +82,7 @@ branchFileRef branch f = Ref $ fromRef' branch <> ":" <> toInternalGitPath f
 
 {- Converts a Ref to refer to the content of the Ref on a given date. -}
 dateRef :: Ref -> RefDate -> Ref
-dateRef r (RefDate d) = Ref $ fromRef' r <> "@" <> encodeBS' d
+dateRef r (RefDate d) = Ref $ fromRef' r <> "@" <> encodeBS d
 
 {- A Ref that can be used to refer to a file in the repository as it
  - appears in a given Ref. -}
@@ -177,7 +177,7 @@ tree (Ref ref) = extractSha <$$> pipeReadStrict
 	[ Param "rev-parse"
 	, Param "--verify"
 	, Param "--quiet"
-	, Param (decodeBS' ref')
+	, Param (decodeBS ref')
 	]
   where
 	ref' = if ":" `S.isInfixOf` ref
diff --git a/Git/Remote.hs b/Git/Remote.hs
index 8f5d99f0d4..80acccaf4c 100644
--- a/Git/Remote.hs
+++ b/Git/Remote.hs
@@ -37,7 +37,7 @@ remoteKeyToRemoteName :: ConfigKey -> Maybe RemoteName
 remoteKeyToRemoteName (ConfigKey k)
 	| "remote." `S.isPrefixOf` k = 
 		let n = S.intercalate "." $ dropFromEnd 1 $ drop 1 $ S8.split '.' k
-		in if S.null n then Nothing else Just (decodeBS' n)
+		in if S.null n then Nothing else Just (decodeBS n)
 	| otherwise = Nothing
 
 {- Construct a legal git remote name out of an arbitrary input string.
@@ -90,7 +90,7 @@ parseRemoteLocation s repo = ret $ calcloc s
 		| null insteadofs = l
 		| otherwise = replacement ++ drop (S.length bestvalue) l
 	  where
-		replacement = decodeBS' $ S.drop (S.length prefix) $
+		replacement = decodeBS $ S.drop (S.length prefix) $
 			S.take (S.length bestkey - S.length suffix) bestkey
 		(bestkey, bestvalue) = 
 			case maximumBy longestvalue insteadofs of
diff --git a/Git/Repair.hs b/Git/Repair.hs
index d221fa6335..f41677a0d9 100644
--- a/Git/Repair.hs
+++ b/Git/Repair.hs
@@ -252,7 +252,7 @@ getAllRefs r = getAllRefs' (fromRawFilePath (localGitDir r) </> "refs")
 getAllRefs' :: FilePath -> IO [Ref]
 getAllRefs' refdir = do
 	let topsegs = length (splitPath refdir) - 1
-	let toref = Ref . encodeBS' . joinPath . drop topsegs . splitPath
+	let toref = Ref . encodeBS . joinPath . drop topsegs . splitPath
 	map toref <$> dirContentsRecursive refdir
 
 explodePackedRefsFile :: Repo -> IO ()
@@ -279,8 +279,8 @@ packedRefsFile r = fromRawFilePath (localGitDir r) </> "packed-refs"
 parsePacked :: String -> Maybe (Sha, Ref)
 parsePacked l = case words l of
 	(sha:ref:[])
-		| isJust (extractSha (encodeBS' sha)) && Ref.legal True ref ->
-			Just (Ref (encodeBS' sha), Ref (encodeBS' ref))
+		| isJust (extractSha (encodeBS sha)) && Ref.legal True ref ->
+			Just (Ref (encodeBS sha), Ref (encodeBS ref))
 	_ -> Nothing
 
 {- git-branch -d cannot be used to remove a branch that is directly
@@ -350,8 +350,8 @@ verifyCommit missing goodcommits commit r
   where
 	parse l = case words l of
 		(commitsha:treesha:[]) -> (,)
-			<$> extractSha (encodeBS' commitsha)
-			<*> extractSha (encodeBS' treesha)
+			<$> extractSha (encodeBS commitsha)
+			<*> extractSha (encodeBS treesha)
 		_ -> Nothing
 	check [] = return True
 	check ((c, t):rest)
@@ -469,7 +469,7 @@ preRepair g = do
   where
 	headfile = localGitDir g P.</> "HEAD"
 	validhead s = "ref: refs/" `isPrefixOf` s
-		|| isJust (extractSha (encodeBS' s))
+		|| isJust (extractSha (encodeBS s))
 
 {- Put it all together. -}
 runRepair :: (Ref -> Bool) -> Bool -> Repo -> IO (Bool, [Branch])
diff --git a/Git/Types.hs b/Git/Types.hs
index db1c71b8f1..68045fc027 100644
--- a/Git/Types.hs
+++ b/Git/Types.hs
@@ -75,7 +75,7 @@ instance Default ConfigValue where
 	def = ConfigValue mempty
 
 fromConfigKey :: ConfigKey -> String
-fromConfigKey (ConfigKey s) = decodeBS' s
+fromConfigKey (ConfigKey s) = decodeBS s
 
 instance Show ConfigKey where
 	show = fromConfigKey
@@ -88,16 +88,16 @@ instance FromConfigValue S.ByteString where
 	fromConfigValue NoConfigValue = mempty
 
 instance FromConfigValue String where
-	fromConfigValue = decodeBS' . fromConfigValue
+	fromConfigValue = decodeBS . fromConfigValue
 
 instance Show ConfigValue where
 	show = fromConfigValue
 
 instance IsString ConfigKey where
-	fromString = ConfigKey . encodeBS'
+	fromString = ConfigKey . encodeBS
 
 instance IsString ConfigValue where
-	fromString = ConfigValue . encodeBS'
+	fromString = ConfigValue . encodeBS
 
 type RemoteName = String
 
@@ -106,7 +106,7 @@ newtype Ref = Ref S.ByteString
 	deriving (Eq, Ord, Read, Show)
 
 fromRef :: Ref -> String
-fromRef = decodeBS' . fromRef'
+fromRef = decodeBS . fromRef'
 
 fromRef' :: Ref -> S.ByteString
 fromRef' (Ref s) = s
diff --git a/Git/UpdateIndex.hs b/Git/UpdateIndex.hs
index 8e406b1ed7..74816a665a 100644
--- a/Git/UpdateIndex.hs
+++ b/Git/UpdateIndex.hs
@@ -80,14 +80,14 @@ lsTree (Ref x) repo streamer = do
 	mapM_ streamer s
 	void $ cleanup
   where
-	params = map Param ["ls-tree", "-z", "-r", "--full-tree", decodeBS' x]
+	params = map Param ["ls-tree", "-z", "-r", "--full-tree", decodeBS x]
 lsSubTree :: Ref -> FilePath -> Repo -> Streamer
 lsSubTree (Ref x) p repo streamer = do
 	(s, cleanup) <- pipeNullSplit params repo
 	mapM_ streamer s
 	void $ cleanup
   where
-	params = map Param ["ls-tree", "-z", "-r", "--full-tree", decodeBS' x, p]
+	params = map Param ["ls-tree", "-z", "-r", "--full-tree", decodeBS x, p]
 
 {- Generates a line suitable to be fed into update-index, to add
  - a given file with a given sha. -}
diff --git a/Key.hs b/Key.hs
index 529c7b7b0d..4d31dcda36 100644
--- a/Key.hs
+++ b/Key.hs
@@ -59,13 +59,13 @@ isChunkKey :: Key -> Bool
 isChunkKey k = isJust (fromKey keyChunkSize k) && isJust (fromKey keyChunkNum k)
 
 serializeKey :: Key -> String
-serializeKey = decodeBS' . serializeKey'
+serializeKey = decodeBS . serializeKey'
 
 serializeKey' :: Key -> S.ByteString
 serializeKey' = keySerialization
 
 deserializeKey :: String -> Maybe Key
-deserializeKey = deserializeKey' . encodeBS'
+deserializeKey = deserializeKey' . encodeBS
 
 deserializeKey' :: S.ByteString -> Maybe Key
 deserializeKey' = eitherToMaybe . A.parseOnly keyParser
diff --git a/Logs/FsckResults.hs b/Logs/FsckResults.hs
index 1ade47d733..017941d370 100644
--- a/Logs/FsckResults.hs
+++ b/Logs/FsckResults.hs
@@ -54,7 +54,7 @@ deserializeFsckResults = deserialize . lines
 	deserialize ("truncated":ls) = deserialize' ls True
 	deserialize ls = deserialize' ls False
 	deserialize' ls t =
-		let s = S.fromList $ map (Ref . encodeBS') ls
+		let s = S.fromList $ map (Ref . encodeBS) ls
 		in if S.null s then FsckFailed else FsckFoundMissing s t
 
 clearFsckResults :: UUID -> Annex ()
diff --git a/Logs/Transfer.hs b/Logs/Transfer.hs
index be6cc87b86..bfee177543 100644
--- a/Logs/Transfer.hs
+++ b/Logs/Transfer.hs
@@ -35,7 +35,7 @@ describeTransfer :: Transfer -> TransferInfo -> String
 describeTransfer t info = unwords
 	[ show $ transferDirection t
 	, show $ transferUUID t
-	, decodeBS' $ actionItemDesc $ ActionItemAssociatedFile
+	, decodeBS $ actionItemDesc $ ActionItemAssociatedFile
 		(associatedFile info)
 		(transferKey t)
 	, show $ bytesComplete info
diff --git a/Logs/View.hs b/Logs/View.hs
index f76a9b9ec2..4a021b64fe 100644
--- a/Logs/View.hs
+++ b/Logs/View.hs
@@ -74,7 +74,7 @@ branchView view
 	| B.null name = Git.Ref branchViewPrefix
 	| otherwise = Git.Ref $ branchViewPrefix <> "/" <> name
   where
-	name = encodeBS' $
+	name = encodeBS $
 		intercalate ";" $ map branchcomp (viewComponents view)
 	branchcomp c
 		| viewVisible c = branchcomp' c
diff --git a/Messages.hs b/Messages.hs
index bc81fd88fb..f261862ace 100644
--- a/Messages.hs
+++ b/Messages.hs
@@ -72,18 +72,18 @@ import qualified Annex
 
 showStart :: String -> RawFilePath -> SeekInput -> Annex ()
 showStart command file si = outputMessage json $
-	encodeBS' command <> " " <> file <> " "
+	encodeBS command <> " " <> file <> " "
   where
 	json = JSON.start command (Just file) Nothing si
 
 showStartKey :: String -> Key -> ActionItem -> SeekInput -> Annex ()
 showStartKey command key ai si = outputMessage json $
-	encodeBS' command <> " " <> actionItemDesc ai <> " "
+	encodeBS command <> " " <> actionItemDesc ai <> " "
   where
 	json = JSON.start command (actionItemFile ai) (Just key) si
 
 showStartOther :: String -> Maybe String -> SeekInput -> Annex ()
-showStartOther command mdesc si = outputMessage json $ encodeBS' $
+showStartOther command mdesc si = outputMessage json $ encodeBS $
 	command ++ (maybe "" (" " ++) mdesc) ++ " "
   where
 	json = JSON.start command Nothing Nothing si
@@ -116,7 +116,7 @@ showEndMessage (StartNoMessage _) = const noop
 showEndMessage (CustomOutput _) = const noop
 
 showNote :: String -> Annex ()
-showNote s = outputMessage (JSON.note s) $ encodeBS' $ "(" ++ s ++ ") "
+showNote s = outputMessage (JSON.note s) $ encodeBS $ "(" ++ s ++ ") "
 
 showAction :: String -> Annex ()
 showAction s = showNote $ s ++ "..."
@@ -131,7 +131,7 @@ showSideAction m = Annex.getState Annex.output >>= go
 			Annex.changeState $ \s -> s { Annex.output = st' }
 		| sideActionBlock st == InBlock = return ()
 		| otherwise = go'
-	go' = outputMessage JSON.none $ encodeBS' $ "(" ++ m ++ "...)\n"
+	go' = outputMessage JSON.none $ encodeBS $ "(" ++ m ++ "...)\n"
 			
 showStoringStateAction :: Annex ()
 showStoringStateAction = showSideAction "recording state in git"
@@ -175,7 +175,7 @@ showOutput = unlessM commandProgressDisabled $
 	outputMessage JSON.none "\n"
 
 showLongNote :: String -> Annex ()
-showLongNote s = outputMessage (JSON.note s) (encodeBS' (formatLongNote s))
+showLongNote s = outputMessage (JSON.note s) (encodeBS (formatLongNote s))
 
 formatLongNote :: String -> String
 formatLongNote s = '\n' : indent s ++ "\n"
@@ -184,7 +184,7 @@ formatLongNote s = '\n' : indent s ++ "\n"
 -- to console, but json object containing the info is emitted immediately.
 showInfo :: String -> Annex ()
 showInfo s = outputMessage' outputJSON (JSON.info s) $
-	encodeBS' (formatLongNote s)
+	encodeBS (formatLongNote s)
 
 showEndOk :: Annex ()
 showEndOk = showEndResult True
diff --git a/P2P/Protocol.hs b/P2P/Protocol.hs
index 353167406d..cd7f24d863 100644
--- a/P2P/Protocol.hs
+++ b/P2P/Protocol.hs
@@ -172,7 +172,7 @@ instance Proto.Serializable Service where
 instance Proto.Serializable ProtoAssociatedFile where
 	serialize (ProtoAssociatedFile (AssociatedFile Nothing)) = ""
 	serialize (ProtoAssociatedFile (AssociatedFile (Just af))) = 
-		decodeBS' $ toInternalGitPath $ encodeBS' $ concatMap esc $ fromRawFilePath af
+		decodeBS $ toInternalGitPath $ encodeBS $ concatMap esc $ fromRawFilePath af
 	  where
 		esc '%' = "%%"
 		esc c 
diff --git a/Remote.hs b/Remote.hs
index 588457f728..b3207bd6d1 100644
--- a/Remote.hs
+++ b/Remote.hs
@@ -153,7 +153,7 @@ byName' n = go . filter matching <$> remoteList
 
 {- Finds the remote or remote group matching the name. -}
 byNameOrGroup :: RemoteName -> Annex [Remote]
-byNameOrGroup n = go =<< getConfigMaybe (ConfigKey ("remotes." <> encodeBS' n))
+byNameOrGroup n = go =<< getConfigMaybe (ConfigKey ("remotes." <> encodeBS n))
   where
 	go (Just l) = catMaybes
 		<$> mapM (byName . Just) (splitc ' ' (fromConfigValue l))
diff --git a/Remote/Adb.hs b/Remote/Adb.hs
index d023d6f25d..5114fa465e 100644
--- a/Remote/Adb.hs
+++ b/Remote/Adb.hs
@@ -307,7 +307,7 @@ listImportableContentsM serial adir = adbfind >>= \case
 	mk ('S':'T':'\t':l) =
 		let (stat, fn) = separate (== '\t') l
 		    sz = fromMaybe 0 (readish (takeWhile (/= ' ') stat))
-		    cid = ContentIdentifier (encodeBS' stat)
+		    cid = ContentIdentifier (encodeBS stat)
 		    loc = mkImportLocation $ toRawFilePath $ 
 		    	Posix.makeRelative (fromAndroidPath adir) fn
 		in Just (loc, (cid, sz))
@@ -440,7 +440,7 @@ getExportContentIdentifier serial adir loc = do
 	return $ case ls of
 		Just ["n"] -> Right Nothing
 		Just (('S':'T':'\t':stat):[]) -> Right $ Just $
-			ContentIdentifier (encodeBS' stat)
+			ContentIdentifier (encodeBS stat)
 		_ -> Left (ExitFailure 1)
   where
 	aloc = fromAndroidPath $ androidExportLocation adir loc
diff --git a/Remote/Borg.hs b/Remote/Borg.hs
index 1a30c5385a..3cf4888448 100644
--- a/Remote/Borg.hs
+++ b/Remote/Borg.hs
@@ -149,7 +149,7 @@ borgLocal :: BorgRepo -> Bool
 borgLocal (BorgRepo r) = notElem ':' r
 
 borgArchive :: BorgRepo -> BorgArchiveName -> String
-borgArchive (BorgRepo r) n = r ++ "::" ++ decodeBS' n
+borgArchive (BorgRepo r) n = r ++ "::" ++ decodeBS n
 
 absBorgRepo :: BorgRepo -> IO BorgRepo
 absBorgRepo r@(BorgRepo p)
diff --git a/Remote/GCrypt.hs b/Remote/GCrypt.hs
index 3d710e40f8..c224a14bec 100644
--- a/Remote/GCrypt.hs
+++ b/Remote/GCrypt.hs
@@ -311,7 +311,7 @@ setupRepo gcryptid r
 			, Param tmpconfig
 			]
 		liftIO $ do
-			void $ Git.Config.changeFile tmpconfig coreGCryptId (encodeBS' gcryptid)
+			void $ Git.Config.changeFile tmpconfig coreGCryptId (encodeBS gcryptid)
 			void $ Git.Config.changeFile tmpconfig denyNonFastForwards (Git.Config.boolConfig' False)
 		ok <- liftIO $ rsync $ opts ++
 			[ Param "--recursive"
diff --git a/Remote/GitLFS.hs b/Remote/GitLFS.hs
index c9d0cc2633..0ceddd3d3a 100644
--- a/Remote/GitLFS.hs
+++ b/Remote/GitLFS.hs
@@ -213,7 +213,7 @@ configKnownUrl r
 	set k v r' = do
 		let k' = remoteAnnexConfig r' k
 		setConfig k' v
-		return $ Git.Config.store' k' (Git.ConfigValue (encodeBS' v)) r'
+		return $ Git.Config.store' k' (Git.ConfigValue (encodeBS v)) r'
 
 data LFSHandle = LFSHandle
 	{ downloadEndpoint :: Maybe LFS.Endpoint
diff --git a/Remote/Helper/Special.hs b/Remote/Helper/Special.hs
index e7e0243cd4..dc5689e028 100644
--- a/Remote/Helper/Special.hs
+++ b/Remote/Helper/Special.hs
@@ -68,13 +68,13 @@ findSpecialRemotes s = do
 		(pure Git.Construct.fromUnknown)
 	match (ConfigKey k) _ =
 		"remote." `S.isPrefixOf` k 
-		&& (".annex-" <> encodeBS' s) `S.isSuffixOf` k
+		&& (".annex-" <> encodeBS s) `S.isSuffixOf` k
 
 {- Sets up configuration for a special remote in .git/config. -}
 gitConfigSpecialRemote :: UUID -> RemoteConfig -> [(String, String)] -> Annex ()
 gitConfigSpecialRemote u c cfgs = do
 	forM_ cfgs $ \(k, v) -> 
-		setConfig (remoteAnnexConfig c (encodeBS' k)) v
+		setConfig (remoteAnnexConfig c (encodeBS k)) v
 	storeUUIDIn (remoteAnnexConfig c "uuid") u
 
 -- RetrievalVerifiableKeysSecure unless overridden by git config.
diff --git a/Remote/Hook.hs b/Remote/Hook.hs
index ab3f53524a..23ab1f5729 100644
--- a/Remote/Hook.hs
+++ b/Remote/Hook.hs
@@ -131,8 +131,8 @@ lookupHook hookname action = do
 				else return $ Just fallback
 		else return $ Just command
   where
-	hook = annexConfig $ encodeBS' $ hookname ++ "-" ++ action ++ "-hook"
-	hookfallback = annexConfig $ encodeBS' $ hookname ++ "-hook"
+	hook = annexConfig $ encodeBS $ hookname ++ "-" ++ action ++ "-hook"
+	hookfallback = annexConfig $ encodeBS $ hookname ++ "-hook"
 
 runHook :: HookName -> Action -> Key -> Maybe FilePath -> Annex ()
 runHook hook action k f = lookupHook hook action >>= \case
diff --git a/Test/Framework.hs b/Test/Framework.hs
index 626302b248..f5b380f26f 100644
--- a/Test/Framework.hs
+++ b/Test/Framework.hs
@@ -108,7 +108,7 @@ inmainrepo a = do
 
 with_ssh_origin :: (Assertion -> Assertion) -> (Assertion -> Assertion)
 with_ssh_origin cloner a = cloner $ do
-	let k = Git.Types.ConfigKey (encodeBS' config)
+	let k = Git.Types.ConfigKey (encodeBS config)
 	let v = Git.Types.ConfigValue (toRawFilePath "/dev/null")
 	origindir <- absPath . Git.Types.fromConfigValue
 		=<< annexeval (Config.getConfig k v)
diff --git a/Types/ActionItem.hs b/Types/ActionItem.hs
index b5d52f5401..e797969b79 100644
--- a/Types/ActionItem.hs
+++ b/Types/ActionItem.hs
@@ -65,7 +65,7 @@ actionItemDesc (ActionItemBranchFilePath bfp _) = descBranchFilePath bfp
 actionItemDesc (ActionItemFailedTransfer t i) = actionItemDesc $
 	ActionItemAssociatedFile (associatedFile i) (transferKey t)
 actionItemDesc (ActionItemTreeFile f) = f
-actionItemDesc (ActionItemOther s) = encodeBS' (fromMaybe "" s)
+actionItemDesc (ActionItemOther s) = encodeBS (fromMaybe "" s)
 actionItemDesc (OnlyActionOn _ ai) = actionItemDesc ai
 
 actionItemKey :: ActionItem -> Maybe Key
diff --git a/Types/GitConfig.hs b/Types/GitConfig.hs
index c058fc1619..70c24cccfc 100644
--- a/Types/GitConfig.hs
+++ b/Types/GitConfig.hs
@@ -476,4 +476,4 @@ remoteAnnexConfigEnd key = "annex-" <> key
 {- A per-remote setting in git config. -}
 remoteConfig :: RemoteNameable r => r -> UnqualifiedConfigKey -> ConfigKey
 remoteConfig r key = ConfigKey $
-	"remote." <> encodeBS' (getRemoteName r) <> "." <> key
+	"remote." <> encodeBS (getRemoteName r) <> "." <> key
diff --git a/Types/UUID.hs b/Types/UUID.hs
index b15fc39d7e..3e59fc685c 100644
--- a/Types/UUID.hs
+++ b/Types/UUID.hs
@@ -48,10 +48,10 @@ instance ToUUID B.ByteString where
 		| otherwise = UUID b
 
 instance FromUUID String where
-	fromUUID s = decodeBS' (fromUUID s)
+	fromUUID s = decodeBS (fromUUID s)
 
 instance ToUUID String where
-	toUUID s = toUUID (encodeBS' s)
+	toUUID s = toUUID (encodeBS s)
 
 instance FromUUID ConfigValue where
 	fromUUID s = (ConfigValue (fromUUID s))
diff --git a/Upgrade/V2.hs b/Upgrade/V2.hs
index 091655d19d..6ba538634a 100644
--- a/Upgrade/V2.hs
+++ b/Upgrade/V2.hs
@@ -93,7 +93,7 @@ logFiles dir = return . filter (".log" `isSuffixOf`)
 push :: Annex ()
 push = do
 	origin_master <- inRepo $ Git.Ref.exists $ 
-		Git.Ref $ encodeBS' "origin/master"
+		Git.Ref $ encodeBS "origin/master"
 	origin_gitannex <- Annex.Branch.hasOrigin
 	case (origin_master, origin_gitannex) of
 		(_, True) -> do
diff --git a/Upgrade/V5/Direct.hs b/Upgrade/V5/Direct.hs
index e1c8ac4e41..9903f84d07 100644
--- a/Upgrade/V5/Direct.hs
+++ b/Upgrade/V5/Direct.hs
@@ -60,7 +60,7 @@ setIndirect = do
 fromDirectBranch :: Ref -> Ref
 fromDirectBranch directhead = case splitc '/' $ fromRef directhead of
 	("refs":"heads":"annex":"direct":rest) -> 
-		Ref $ encodeBS' $ "refs/heads/" ++ intercalate "/" rest
+		Ref $ encodeBS $ "refs/heads/" ++ intercalate "/" rest
 	_ -> directhead
 
 switchHEADBack :: Annex ()
diff --git a/Utility/Data.hs b/Utility/Data.hs
index 55108457d6..faf9b34ecc 100644
--- a/Utility/Data.hs
+++ b/Utility/Data.hs
@@ -1,6 +1,6 @@
 {- utilities for simple data types
  -
- - Copyright 2013 Joey Hess <id@joeyh.name>
+ - Copyright 2013-2021 Joey Hess <id@joeyh.name>
  -
  - License: BSD-2-clause
  -}
@@ -10,8 +10,12 @@
 module Utility.Data (
 	firstJust,
 	eitherToMaybe,
+	s2w8,
+	w82s,
 ) where
 
+import Data.Word
+
 {- First item in the list that is not Nothing. -}
 firstJust :: Eq a => [Maybe a] -> Maybe a
 firstJust ms = case dropWhile (== Nothing) ms of
@@ -20,3 +24,15 @@ firstJust ms = case dropWhile (== Nothing) ms of
 
 eitherToMaybe :: Either a b -> Maybe b
 eitherToMaybe = either (const Nothing) Just
+
+c2w8 :: Char -> Word8
+c2w8 = fromIntegral . fromEnum
+
+w82c :: Word8 -> Char
+w82c = toEnum . fromIntegral
+
+s2w8 :: String -> [Word8]
+s2w8 = map c2w8
+
+w82s :: [Word8] -> String
+w82s = map w82c
diff --git a/Utility/Debug.hs b/Utility/Debug.hs
index e0be9c9254..6e6e701162 100644
--- a/Utility/Debug.hs
+++ b/Utility/Debug.hs
@@ -34,7 +34,7 @@ newtype DebugSource = DebugSource S.ByteString
 	deriving (Eq, Show)
 
 instance IsString DebugSource where
-	fromString = DebugSource . encodeBS'
+	fromString = DebugSource . encodeBS
 
 -- | Selects whether to display a message from a source.
 data DebugSelector 
@@ -97,6 +97,6 @@ fastDebug (DebugSelector p) src msg
 
 formatDebugMessage :: DebugSource -> String -> IO S.ByteString
 formatDebugMessage (DebugSource src) msg = do
-	t <- encodeBS' . formatTime defaultTimeLocale "[%F %X%Q]"
+	t <- encodeBS . formatTime defaultTimeLocale "[%F %X%Q]"
 		<$> getZonedTime
 	return (t <> " (" <> src <> ") " <> encodeBS msg)
diff --git a/Utility/FileSystemEncoding.hs b/Utility/FileSystemEncoding.hs
index 4690d5fa63..b58f4438a1 100644
--- a/Utility/FileSystemEncoding.hs
+++ b/Utility/FileSystemEncoding.hs
@@ -1,6 +1,6 @@
 {- GHC File system encoding handling.
  -
- - Copyright 2012-2016 Joey Hess <id@joeyh.name>
+ - Copyright 2012-2021 Joey Hess <id@joeyh.name>
  -
  - License: BSD-2-clause
  -}
@@ -18,36 +18,22 @@ module Utility.FileSystemEncoding (
 	encodeBL,
 	decodeBS,
 	encodeBS,
-	decodeBL',
-	encodeBL',
-	decodeBS',
-	encodeBS',
 	truncateFilePath,
-	s2w8,
-	w82s,
-	c2w8,
-	w82c,
 ) where
 
 import qualified GHC.Foreign as GHC
 import qualified GHC.IO.Encoding as Encoding
-import Foreign.C
 import System.IO
 import System.IO.Unsafe
-import Data.Word
 import System.FilePath.ByteString (RawFilePath, encodeFilePath, decodeFilePath)
 import qualified Data.ByteString as S
 import qualified Data.ByteString.Lazy as L
+import Data.ByteString.Unsafe (unsafePackMallocCStringLen)
 #ifdef mingw32_HOST_OS
 import qualified Data.ByteString.UTF8 as S8
 import qualified Data.ByteString.Lazy.UTF8 as L8
-#else
-import Data.List
-import Utility.Split
 #endif
 
-import Utility.Exception
-
 {- Makes all subsequent Handles that are opened, as well as stdio Handles,
  - use the filesystem encoding, instead of the encoding of the current
  - locale.
@@ -80,32 +66,10 @@ fileEncoding h = hSetEncoding h =<< Encoding.getFileSystemEncoding
 fileEncoding h = hSetEncoding h Encoding.utf8
 #endif
 
-{- Encodes a FilePath into a String, applying the filesystem encoding.
- -
- - There are very few things it makes sense to do with such an encoded
- - string. It's not a legal filename; it should not be displayed.
- - So this function is not exported, but instead used by the few functions
- - that can usefully consume it.
- -
- - This use of unsafePerformIO is belived to be safe; GHC's interface
- - only allows doing this conversion with CStrings, and the CString buffer
- - is allocated, used, and deallocated within the call, with no side
- - effects.
- -
- - If the FilePath contains a value that is not legal in the filesystem
- - encoding, rather than thowing an exception, it will be returned as-is.
- -}
-{-# NOINLINE _encodeFilePath #-}
-_encodeFilePath :: FilePath -> String
-_encodeFilePath fp = unsafePerformIO $ do
-	enc <- Encoding.getFileSystemEncoding
-	GHC.withCString enc fp (GHC.peekCString Encoding.char8)
-		`catchNonAsync` (\_ -> return fp)
-
 {- Decodes a ByteString into a FilePath, applying the filesystem encoding. -}
 decodeBL :: L.ByteString -> FilePath
 #ifndef mingw32_HOST_OS
-decodeBL = encodeW8NUL . L.unpack
+decodeBL = decodeBS . L.toStrict
 #else
 {- On Windows, we assume that the ByteString is utf-8, since Windows
  - only uses unicode for filenames. -}
@@ -115,104 +79,45 @@ decodeBL = L8.toString
 {- Encodes a FilePath into a ByteString, applying the filesystem encoding. -}
 encodeBL :: FilePath -> L.ByteString
 #ifndef mingw32_HOST_OS
-encodeBL = L.pack . decodeW8NUL
+encodeBL = L.fromStrict . encodeBS
 #else
 encodeBL = L8.fromString
 #endif
 
 decodeBS :: S.ByteString -> FilePath
 #ifndef mingw32_HOST_OS
-decodeBS = encodeW8NUL . S.unpack
+-- This is a copy of code from System.FilePath.Internal.decodeFilePath.
+-- However, older versions of that library truncated at NUL, which this
+-- must not do, because it may end up used on something other than a unix
+-- filepath.
+{-# NOINLINE decodeBS #-}
+decodeBS b = unsafePerformIO $ do
+	enc <- Encoding.getFileSystemEncoding
+	S.useAsCStringLen b (GHC.peekCStringLen enc)
 #else
 decodeBS = S8.toString
 #endif
 
 encodeBS :: FilePath -> S.ByteString
 #ifndef mingw32_HOST_OS
-encodeBS = S.pack . decodeW8NUL
+-- This is a copy of code from System.FilePath.Internal.encodeFilePath.
+-- However, older versions of that library truncated at NUL, which this
+-- must not do, because it may end up used on something other than a unix
+-- filepath.
+{-# NOINLINE encodeBS #-}
+encodeBS f = unsafePerformIO $ do
+	enc <- Encoding.getFileSystemEncoding
+	GHC.newCStringLen enc f >>= unsafePackMallocCStringLen
 #else
 encodeBS = S8.fromString
 #endif
 
-{- Faster version that assumes the string does not contain NUL;
- - if it does it will be truncated before the NUL. -}
-decodeBS' :: S.ByteString -> FilePath
-#ifndef mingw32_HOST_OS
-decodeBS' = encodeW8 . S.unpack
-#else
-decodeBS' = S8.toString
-#endif
-
-encodeBS' :: FilePath -> S.ByteString
-#ifndef mingw32_HOST_OS
-encodeBS' = S.pack . decodeW8
-#else
-encodeBS' = S8.fromString
-#endif
-
-decodeBL' :: L.ByteString -> FilePath
-#ifndef mingw32_HOST_OS
-decodeBL' = encodeW8 . L.unpack
-#else
-decodeBL' = L8.toString
-#endif
-
-encodeBL' :: FilePath -> L.ByteString
-#ifndef mingw32_HOST_OS
-encodeBL' = L.pack . decodeW8
-#else
-encodeBL' = L8.fromString
-#endif
-
 fromRawFilePath :: RawFilePath -> FilePath
 fromRawFilePath = decodeFilePath
 
 toRawFilePath :: FilePath -> RawFilePath
 toRawFilePath = encodeFilePath
 
-#ifndef mingw32_HOST_OS
-{- Converts a [Word8] to a FilePath, encoding using the filesystem encoding.
- -
- - w82s produces a String, which may contain Chars that are invalid
- - unicode. From there, this is really a simple matter of applying the
- - file system encoding, only complicated by GHC's interface to doing so.
- -
- - Note that the encoding stops at any NUL in the input. FilePaths
- - cannot contain embedded NUL, but Haskell Strings may.
- -}
-{-# NOINLINE encodeW8 #-}
-encodeW8 :: [Word8] -> FilePath
-encodeW8 w8 = unsafePerformIO $ do
-	enc <- Encoding.getFileSystemEncoding
-	GHC.withCString Encoding.char8 (w82s w8) $ GHC.peekCString enc
-
-decodeW8 :: FilePath -> [Word8]
-decodeW8 = s2w8 . _encodeFilePath
-
-{- Like encodeW8 and decodeW8, but NULs are passed through unchanged. -}
-encodeW8NUL :: [Word8] -> FilePath
-encodeW8NUL = intercalate [nul] . map encodeW8 . splitc (c2w8 nul)
-  where
-	nul = '\NUL'
-
-decodeW8NUL :: FilePath -> [Word8]
-decodeW8NUL = intercalate [c2w8 nul] . map decodeW8 . splitc nul
-  where
-	nul = '\NUL'
-#endif
-
-c2w8 :: Char -> Word8
-c2w8 = fromIntegral . fromEnum
-
-w82c :: Word8 -> Char
-w82c = toEnum . fromIntegral
-
-s2w8 :: String -> [Word8]
-s2w8 = map c2w8
-
-w82s :: [Word8] -> String
-w82s = map w82c
-
 {- Truncates a FilePath to the given number of bytes (or less),
  - as represented on disk.
  -
@@ -224,8 +129,8 @@ truncateFilePath :: Int -> FilePath -> FilePath
 truncateFilePath n = go . reverse
   where
 	go f =
-		let bytes = decodeW8 f
-		in if length bytes <= n
+		let b = encodeBS f
+		in if S.length b <= n
 			then reverse f
 			else go (drop 1 f)
 #else