Revert "lock journal before reading journal files"

This reverts commit 47358a6f956681346a198cdf27c60bcf9498cc45.

This added overhead, and will not be needed, because appends are going
to have to be made atomic for other reasons than avoiding incomplete
reads of data being appended.

In particular, when git-annex is interrupted in the middle of an append,
it must not leave the file with a partially written line. So appending
has to somehow be made fully atomic.

diff --git a/Annex/Branch.hs b/Annex/Branch.hs
index 3e489e457dbf589adac2f2e5afe69b5cb774309b..4c84430b3c8a8852488de28bf72ec923f8fc8b37 100644 (file)
--- a/Annex/Branch.hs
+++ b/Annex/Branch.hs
@@ -236,7 +236,7 @@ updateTo' pairs = do
                        else return $ "merging " ++
                                unwords (map Git.Ref.describe branches) ++ 
                                " into " ++ fromRef name
-               localtransitions <- getLocalTransitions jl
+               localtransitions <- getLocalTransitions
                unless (null tomerge) $ do
                        showSideAction merge_desc
                        mapM_ checkBranchDifferences refs
@@ -265,7 +265,7 @@ updateTo' pairs = do
                -- Gather any transitions that are new to either the
                -- local branch or a remote ref, which will need to be
                -- applied on the fly.
-               localts <- lockJournal getLocalTransitions
+               localts <- getLocalTransitions
                remotets <- mapM getRefTransitions refs
                ts <- if all (localts ==) remotets
                        then return []
@@ -307,14 +307,13 @@ get file = do
                        content <- if journalIgnorable st
                                then getRef fullname file
                                else if null (unmergedRefs st) 
-                                       then lockJournal $ 
-                                               \jl -> getLocal jl file
+                                       then getLocal file
                                        else unmergedbranchfallback st
                        setCache file content
                        return content
   where
        unmergedbranchfallback st = do
-               l <- lockJournal $ \jl -> getLocal jl file
+               l <- getLocal file
                bs <- forM (unmergedRefs st) $ \ref -> getRef ref file
                let content = l <> mconcat bs
                return $ applytransitions (unhandledTransitions st) content
@@ -344,7 +343,7 @@ precache file branchcontent = do
        st <- getState
        content <- if journalIgnorable st
                then pure branchcontent
-               else lockJournal $ \jl -> getJournalFile jl (GetPrivate True) file >>= return . \case
+               else getJournalFileStale (GetPrivate True) file >>= return . \case
                        NoJournalledContent -> branchcontent
                        JournalledContent journalcontent -> journalcontent
                        PossiblyStaleJournalledContent journalcontent ->
@@ -355,13 +354,13 @@ precache file branchcontent = do
  - reflect changes in remotes.
  - (Changing the value this returns, and then merging is always the
  - same as using get, and then changing its value.) -}
-getLocal :: JournalLocked -> RawFilePath -> Annex L.ByteString
-getLocal jl = getLocal' jl (GetPrivate True)
+getLocal :: RawFilePath -> Annex L.ByteString
+getLocal = getLocal' (GetPrivate True)
 
-getLocal' :: JournalLocked -> GetPrivate -> RawFilePath -> Annex L.ByteString
-getLocal' jl getprivate file = do
+getLocal' :: GetPrivate -> RawFilePath -> Annex L.ByteString
+getLocal' getprivate file = do
        fastDebug "Annex.Branch" ("read " ++ fromRawFilePath file)
-       go =<< getJournalFile jl getprivate file
+       go =<< getJournalFileStale getprivate file
   where
        go NoJournalledContent = getRef fullname file
        go (JournalledContent journalcontent) = return journalcontent
@@ -395,12 +394,12 @@ getRef ref file = withIndex $ catFile ref file
  - modifes the current content of the file on the branch.
  -}
 change :: Journalable content => RegardingUUID -> RawFilePath -> (L.ByteString -> content) -> Annex ()
-change ru file f = lockJournal $ \jl -> f <$> getToChange jl ru file >>= set jl ru file
+change ru file f = lockJournal $ \jl -> f <$> getToChange ru file >>= set jl ru file
 
 {- Applies a function which can modify the content of a file, or not. -}
 maybeChange :: Journalable content => RegardingUUID -> RawFilePath -> (L.ByteString -> Maybe content) -> Annex ()
 maybeChange ru file f = lockJournal $ \jl -> do
-       v <- getToChange jl ru file
+       v <- getToChange ru file
        case f v of
                Just jv ->
                        let b = journalableByteString jv
@@ -421,8 +420,8 @@ changeOrAppend ru file f = lockJournal $ \jl -> do
                Append toappend -> append jl ru file oldc toappend
 
 {- Only get private information when the RegardingUUID is itself private. -}
-getToChange :: JournalLocked -> RegardingUUID -> RawFilePath -> Annex L.ByteString
-getToChange jl ru f = flip (getLocal' jl) f . GetPrivate =<< regardingPrivateUUID ru
+getToChange :: RegardingUUID -> RawFilePath -> Annex L.ByteString
+getToChange ru f = flip getLocal' f . GetPrivate =<< regardingPrivateUUID ru
 
 {- Records new content of a file into the journal.
  -
@@ -708,10 +707,10 @@ stageJournal jl commitindex = withIndex $ withOtherTmp $ \tmpdir -> do
                removeWhenExistsWith (R.removeLink) (toRawFilePath jlogf)
        openjlog tmpdir = liftIO $ openTmpFileIn tmpdir "jlog"
 
-getLocalTransitions :: JournalLocked -> Annex Transitions
-getLocalTransitions jl = 
+getLocalTransitions :: Annex Transitions
+getLocalTransitions = 
        parseTransitionsStrictly "local"
-               <$> getLocal jl transitionsLog
+               <$> getLocal transitionsLog
 
 {- This is run after the refs have been merged into the index,
  - but before the result is committed to the branch.
@@ -960,7 +959,7 @@ overBranchFileContents' select go st = do
        -- Check the journal, in case it did not get committed to the branch
        checkjournal f branchcontent
                | journalIgnorable st = return branchcontent
-               | otherwise = lockJournal $ \jl -> getJournalFile jl (GetPrivate True) f >>= return . \case
+               | otherwise = getJournalFileStale (GetPrivate True) f >>= return . \case
                        NoJournalledContent -> branchcontent
                        JournalledContent journalledcontent ->
                                Just journalledcontent
@@ -970,7 +969,7 @@ overBranchFileContents' select go st = do
        drain buf fs = case getnext fs of
                Just (v, f, fs') -> do
                        liftIO $ putMVar buf fs'
-                       content <- lockJournal $ \jl -> getJournalFile jl (GetPrivate True) f >>= \case
+                       content <- getJournalFileStale (GetPrivate True) f >>= \case
                                NoJournalledContent -> return Nothing
                                JournalledContent journalledcontent ->
                                        return (Just journalledcontent)