Avoid repeated location log commits when a remote is receiving files.

Done by adding a oneshot mode, in which location log changes are written to
the journal, but not committed. Taking advantage of git-annex's existing
ability to recover in this situation.

This is used by git-annex-shell and other places where changes are made to
a remote's location log.

1 files changed, 9 insertions, 4 deletions

diff --git a/Annex/Content.hs b/Annex/Content.hs
index c21ac405e..dcfd43866 100644
--- a/Annex/Content.hs
+++ b/Annex/Content.hs
@@ -291,11 +291,16 @@ getKeysPresent' dir = do
 			let files = concat contents
 			return $ mapMaybe (fileKey . takeFileName) files
 
-{- Things to do to record changes to content. -}
-saveState :: Annex ()
-saveState = do
+{- Things to do to record changes to content when shutting down.
+ -
+ - It's acceptable to avoid committing changes to the branch,
+ - especially if performing a short-lived action.
+ -}
+saveState :: Bool -> Annex ()
+saveState oneshot = do
 	Annex.Queue.flush False
-	Annex.Branch.commit "update"
+	unless oneshot $
+		Annex.Branch.commit "update"
 
 {- Downloads content from any of a list of urls. -}
 downloadUrl :: [Url.URLString] -> FilePath -> Annex Bool