From 28b0aaea54e9515c16e440f9f22688dc2e7dc642 Mon Sep 17 00:00:00 2001 From: Joey Hess Date: Mon, 18 Jul 2022 16:40:25 -0400 Subject: [PATCH] re-add lock journal before reading journal files This reverts commit 2e6e9876e3fc420a22eee82eedec54ac3f678878. This is gonna be needed after all.. The append will only be atomic if the journal is locked, because the file being appended will have to be moved out of the way to avoid an old version of git-annex seeing an incomplete write to it. When git-annex finds that the file is not in the journal, and checks the append location, locking will be needed to avoid a race causing it to miss it in the append location too due to it being moved back to the journal. --- Annex/Branch.hs | 39 ++++++++++++++++++++------------------- 1 file changed, 20 insertions(+), 19 deletions(-) diff --git a/Annex/Branch.hs b/Annex/Branch.hs index 456d9d6619..41ae4207f7 100644 --- 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 + localtransitions <- getLocalTransitions jl 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 <- getLocalTransitions + localts <- lockJournal getLocalTransitions remotets <- mapM getRefTransitions refs ts <- if all (localts ==) remotets then return [] @@ -307,13 +307,14 @@ get file = do content <- if journalIgnorable st then getRef fullname file else if null (unmergedRefs st) - then getLocal file + then lockJournal $ + \jl -> getLocal jl file else unmergedbranchfallback st setCache file content return content where unmergedbranchfallback st = do - l <- getLocal file + l <- lockJournal $ \jl -> getLocal jl file bs <- forM (unmergedRefs st) $ \ref -> getRef ref file let content = l <> mconcat bs return $ applytransitions (unhandledTransitions st) content @@ -343,7 +344,7 @@ precache file branchcontent = do st <- getState content <- if journalIgnorable st then pure branchcontent - else getJournalFileStale (GetPrivate True) file >>= return . \case + else lockJournal $ \jl -> getJournalFile jl (GetPrivate True) file >>= return . \case NoJournalledContent -> branchcontent JournalledContent journalcontent -> journalcontent PossiblyStaleJournalledContent journalcontent -> @@ -354,13 +355,13 @@ 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 :: RawFilePath -> Annex L.ByteString -getLocal = getLocal' (GetPrivate True) +getLocal :: JournalLocked -> RawFilePath -> Annex L.ByteString +getLocal jl = getLocal' jl (GetPrivate True) -getLocal' :: GetPrivate -> RawFilePath -> Annex L.ByteString -getLocal' getprivate file = do +getLocal' :: JournalLocked -> GetPrivate -> RawFilePath -> Annex L.ByteString +getLocal' jl getprivate file = do fastDebug "Annex.Branch" ("read " ++ fromRawFilePath file) - go =<< getJournalFileStale getprivate file + go =<< getJournalFile jl getprivate file where go NoJournalledContent = getRef fullname file go (JournalledContent journalcontent) = return journalcontent @@ -394,12 +395,12 @@ 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 ru file >>= set jl ru file +change ru file f = lockJournal $ \jl -> f <$> getToChange jl 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 ru file + v <- getToChange jl ru file case f v of Just jv -> let b = journalableByteString jv @@ -446,8 +447,8 @@ changeOrAppend ru file f = lockJournal $ \jl -> oldc <> journalableByteString toappend {- Only get private information when the RegardingUUID is itself private. -} -getToChange :: RegardingUUID -> RawFilePath -> Annex L.ByteString -getToChange ru f = flip getLocal' f . GetPrivate =<< regardingPrivateUUID ru +getToChange :: JournalLocked -> RegardingUUID -> RawFilePath -> Annex L.ByteString +getToChange jl ru f = flip (getLocal' jl) f . GetPrivate =<< regardingPrivateUUID ru {- Records new content of a file into the journal. - @@ -727,10 +728,10 @@ stageJournal jl commitindex = withIndex $ withOtherTmp $ \tmpdir -> do removeWhenExistsWith (R.removeLink) (toRawFilePath jlogf) openjlog tmpdir = liftIO $ openTmpFileIn tmpdir "jlog" -getLocalTransitions :: Annex Transitions -getLocalTransitions = +getLocalTransitions :: JournalLocked -> Annex Transitions +getLocalTransitions jl = parseTransitionsStrictly "local" - <$> getLocal transitionsLog + <$> getLocal jl transitionsLog {- This is run after the refs have been merged into the index, - but before the result is committed to the branch. @@ -979,7 +980,7 @@ 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 = getJournalFileStale (GetPrivate True) f >>= return . \case + | otherwise = lockJournal $ \jl -> getJournalFile jl (GetPrivate True) f >>= return . \case NoJournalledContent -> branchcontent JournalledContent journalledcontent -> Just journalledcontent @@ -989,7 +990,7 @@ overBranchFileContents' select go st = do drain buf fs = case getnext fs of Just (v, f, fs') -> do liftIO $ putMVar buf fs' - content <- getJournalFileStale (GetPrivate True) f >>= \case + content <- lockJournal $ \jl -> getJournalFile jl (GetPrivate True) f >>= \case NoJournalledContent -> return Nothing JournalledContent journalledcontent -> return (Just journalledcontent)