annex.dbdir fully working

Completes work started in e60766543f

I've verified that all the sqlite databases get stored in annex.dbdir
and are created successfully. If annex.dbdir does not exist, it will be
created; its parent directory must already exist though.

Sponsored-by: Dartmouth College's Datalad project

Annex/Perms.hs

@@ -106,13 +106,16 @@ annexFileMode = withShared $ return . go
 	go _ = stdFileMode
 	sharedmode = combineModes groupSharedModes
 
-{- Creates a directory inside the gitAnnexDir, creating any parent
- - directories up to and including the gitAnnexDir.
+{- Creates a directory inside the gitAnnexDir (or possibly the dbdir), 
+ - creating any parent directories up to and including the gitAnnexDir.
  - Makes directories with appropriate permissions. -}
 createAnnexDirectory :: RawFilePath -> Annex ()
 createAnnexDirectory dir = do
 	top <- parentDir <$> fromRepo gitAnnexDir
-	createDirectoryUnder' [top] dir createdir
+	tops <- annexDbDir <$> Annex.getGitConfig >>= return . \case
+		Nothing -> [top]
+		Just dbdir -> [top, parentDir dbdir]
+	createDirectoryUnder' tops dir createdir
   where
 	createdir p = do
 		liftIO $ R.createDirectory p

Database/Init.hs

@@ -36,11 +36,12 @@ initDb db migration = do
 	let tmpdb = tmpdbdir P.</> "db"
 	let tdb = T.pack (fromRawFilePath tmpdb)
 	gc <- Annex.getGitConfig
-	top <- case annexDbDir gc of
-		Just topdbdir -> pure $ parentDir $ topdbdir
-		Nothing -> parentDir <$> fromRepo gitAnnexDir
+	top <- parentDir <$> fromRepo gitAnnexDir
+	let tops = case annexDbDir gc of
+		Just topdbdir -> [top, parentDir topdbdir]
+		Nothing -> [top]
 	liftIO $ do
-		createDirectoryUnder [top] tmpdbdir
+		createDirectoryUnder tops tmpdbdir
 		runSqliteInfo (enableWAL tdb) migration
 	setAnnexDirPerm tmpdbdir
 	-- Work around sqlite bug that prevents it from honoring

doc/git-annex.mdwn

@@ -1230,7 +1230,7 @@ repository, using [[git-annex-config]]. See its man page for a list.)
 
 * `annex.dbdir`
 
-  Set to a directory where git-annex should store its sqlite databases.
+  The directory where git-annex should store its sqlite databases.
   The default location is inside `.git/annex/`. 
 
   Certian filesystems, such as cifs, may not support locking operations