directory special remote: Made more efficient and robust.

Files are now written to a tmp directory in the remote, and once all
chunks are written, etc, it's moved into the final place atomically.

For now, checkpresent still checks every single chunk of a file, because
the old method could leave partially transferred files with some chunks
present and others not.

Command/SendKey.hs

@@ -12,7 +12,6 @@ import Command
 import Annex.Content
 import Utility.Rsync
 import Logs.Transfer
-import Types.Remote
 import qualified Fields
 
 def :: [Command]

Remote/Directory.hs

@@ -48,7 +48,7 @@ gen r u c = do
  			storeKey = store dir chunksize,
 			retrieveKeyFile = retrieve dir chunksize,
 			retrieveKeyFileCheap = retrieveCheap dir chunksize,
-			removeKey = remove dir chunksize,
+			removeKey = remove dir,
 			hasKey = checkPresent dir chunksize,
 			hasKeyCheap = True,
 			whereisKey = Nothing,
@@ -73,10 +73,19 @@ directorySetup u c = do
 	gitConfigSpecialRemote u c' "directory" dir
 	return $ M.delete "directory" c'
 
-{- Locations to try to access a given Key in the Directory. -}
+{- Locations to try to access a given Key in the Directory.
+ - We try more than since we used to write to different hash directories. -}
 locations :: FilePath -> Key -> [FilePath]
 locations d k = map (d </>) (keyPaths k)
 
+{- Directory where the file(s) for a key are stored. -}
+storeDir :: FilePath -> Key -> FilePath
+storeDir d k = addTrailingPathSeparator $ d </> hashDirLower k </> keyFile k
+
+{- Where we store temporary data for a key as it's being uploaded. -}
+tmpDir :: FilePath -> Key -> FilePath
+tmpDir d k = addTrailingPathSeparator $ d </> "tmp" </> keyFile k
+
 withCheckedFiles :: (FilePath -> IO Bool) -> ChunkSize -> FilePath -> Key -> ([FilePath] -> IO Bool) -> IO Bool
 withCheckedFiles _ _ [] _ _ = return False
 withCheckedFiles check Nothing d k a = go $ locations d k
@@ -159,18 +168,22 @@ storeSplit' meterupdate chunksize (d:dests) bs c = do
 storeHelper :: FilePath -> ChunkSize -> Key -> ([FilePath] -> IO [FilePath]) -> Annex Bool
 storeHelper d chunksize key storer = check <&&> go
   where
-	basedest = Prelude.head $ locations d key
-	dir = parentDir basedest
+	tmpdir = tmpDir d key
+	destdir = storeDir d key
 	{- The size is not exactly known when encrypting the key;
 	 - this assumes that at least the size of the key is
 	 - needed as free space. -}
-	check = checkDiskSpace (Just dir) key 0
-	go = liftIO $ catchBoolIO $ do
-		createDirectoryIfMissing True dir
-		allowWrite dir
-		preventWrite dir `after` storeChunks basedest chunksize storer recorder finalizer
-	finalizer f dest = do
-		renameFile f dest
+	check = do
+		liftIO $ createDirectoryIfMissing True tmpdir
+		checkDiskSpace (Just tmpdir) key 0
+	go = liftIO $ catchBoolIO $
+		storeChunks key tmpdir destdir chunksize storer recorder finalizer
+	finalizer tmp dest = do
+		void $ tryIO $ allowWrite dest -- may already exist
+		void $ tryIO $ removeDirectoryRecursive dest -- or not exist
+		createDirectoryIfMissing True (parentDir dest)
+		renameDirectory tmp dest
+		mapM_ preventWrite =<< dirContents dest
 		preventWrite dest
 	recorder f s = do
 		void $ tryIO $ allowWrite f
@@ -201,16 +214,13 @@ retrieveCheap d _ k f = liftIO $ withStoredFiles Nothing d k go
 	go [file] = catchBoolIO $ createSymbolicLink file f >> return True
 	go _files = return False
 
-remove :: FilePath -> ChunkSize -> Key -> Annex Bool
-remove d chunksize k = liftIO $ withStoredFiles chunksize d k go
+remove :: FilePath -> Key -> Annex Bool
+remove d k = liftIO $ catchBoolIO $ do
+	allowWrite dir
+	removeDirectoryRecursive dir
+	return True
   where
-	go = all id <$$> mapM removefile
-	removefile file = catchBoolIO $ do
-		let dir = parentDir file
-		allowWrite dir
-		removeFile file
-		_ <- tryIO $ removeDirectory dir
-		return True
+	dir = storeDir d k
 
 checkPresent :: FilePath -> ChunkSize -> Key -> Annex (Either String Bool)
 checkPresent d chunksize k = liftIO $ catchMsgIO $ withStoredFiles chunksize d k $

Remote/Helper/Chunked.hs

@@ -58,33 +58,28 @@ chunkStream = map (\n -> ".chunk" ++ show n) [1 :: Integer ..]
 {- Given the base destination to use to store a value,
  - generates a stream of temporary destinations (just one when not chunking)
  - and passes it to an action, which should chunk and store the data,
- - and return the destinations it stored to, or [] on error.
- -
- - Then calles the finalizer to rename the temporary destinations into
- - their final places (and do any other cleanup), and writes the chunk count
- - (if chunking)
+ - and return the destinations it stored to, or [] on error. Then
+ - calls the storer to write the chunk count (if chunking). Finally, the
+ - fianlizer is called to rename the tmp into the dest 
+ - (and do any other cleanup).
  -}
-storeChunks :: FilePath -> ChunkSize -> ([FilePath] -> IO [FilePath]) -> (FilePath -> String -> IO ()) -> (FilePath -> FilePath -> IO ()) -> IO Bool
-storeChunks basedest chunksize storer recorder finalizer =
+storeChunks :: Key -> FilePath -> FilePath -> ChunkSize -> ([FilePath] -> IO [FilePath]) -> (FilePath -> String -> IO ()) -> (FilePath -> FilePath -> IO ()) -> IO Bool
+storeChunks key tmp dest chunksize storer recorder finalizer =
 	either (const $ return False) return
 		=<< (E.try go :: IO (Either E.SomeException Bool))
   where
 	go = do
 		stored <- storer tmpdests
-		forM_ stored $ \d -> do
-			let dest = detmpprefix d
-			finalizer d dest
 		when (chunksize /= Nothing) $ do
-			let chunkcount = basedest ++ chunkCount
+			let chunkcount = basef ++ chunkCount
 			recorder chunkcount (show $ length stored)
+		finalizer tmp dest
 		return (not $ null stored)
 
-	tmpprefix = ".tmp"
-	detmpprefix f = take (length f - tmpprefixlen) f
-	tmpprefixlen = length tmpprefix
+	basef = tmp ++ keyFile key
 	tmpdests
-		| chunksize == Nothing = [basedest ++ tmpprefix]
-		| otherwise = map (++ tmpprefix) $ map (basedest ++) chunkStream
+		| chunksize == Nothing = [basef]
+		| otherwise = map (basef ++ ) chunkStream
 
 {- Given a list of destinations to use, chunks the data according to the
  - ChunkSize, and runs the storer action to store each chunk. Returns

Remote/WebDAV.hs

@@ -90,7 +90,7 @@ store r k _f p = metered (Just p) k $ \meterupdate ->
 		let url = davLocation baseurl k
 		f <- inRepo $ gitAnnexLocation k
 		liftIO $ withMeteredFile f meterupdate $
-			storeHelper r url user pass
+			storeHelper r k url user pass
 
 storeEncrypted :: Remote -> (Cipher, Key) -> Key -> MeterUpdate -> Annex Bool
 storeEncrypted r (cipher, enck) k p = metered (Just p) k $ \meterupdate ->
@@ -98,12 +98,12 @@ storeEncrypted r (cipher, enck) k p = metered (Just p) k $ \meterupdate ->
 		let url = davLocation baseurl enck
 		f <- inRepo $ gitAnnexLocation k
 		liftIO $ encrypt cipher (streamMeteredFile f meterupdate) $
-			readBytes $ storeHelper r url user pass
+			readBytes $ storeHelper r enck url user pass
 
-storeHelper :: Remote -> DavUrl -> DavUser -> DavPass -> L.ByteString -> IO Bool
-storeHelper r urlbase user pass b = catchBoolIO $ do
+storeHelper :: Remote -> Key -> DavUrl -> DavUser -> DavPass -> L.ByteString -> IO Bool
+storeHelper r k urlbase user pass b = catchBoolIO $ do
 	davMkdir (urlParent urlbase) user pass
-	storeChunks urlbase chunksize storer recorder finalizer
+	storeChunks k undefined undefined chunksize storer recorder finalizer
   where
 	chunksize = chunkSize $ config r
 	storer urls = storeChunked chunksize urls storehttp b

debian/changelog

@@ -10,6 +10,7 @@ git-annex (3.20121113) UNRELEASED; urgency=low
   * Getting a file from chunked directory special remotes no longer buffers
     it all in memory.
   * S3: Added progress display for uploading and downloading.
+  * directory special remote: Made more efficient and robust.
 
  -- Joey Hess <joeyh@debian.org>  Tue, 13 Nov 2012 13:17:07 -0400