diff options
| -rw-r--r-- | Annex/Branch.hs | 54 | ||||
| -rw-r--r-- | debian/changelog | 8 |
2 files changed, 48 insertions, 14 deletions
diff --git a/Annex/Branch.hs b/Annex/Branch.hs index 8c8aef7d6..c704cef87 100644 --- a/Annex/Branch.hs +++ b/Annex/Branch.hs @@ -137,7 +137,7 @@ updateTo pairs = do - may still be updated if the branch has gotten ahead - of the index. -} then whenM (needUpdateIndex branchref) $ lockJournal $ \jl -> do - forceUpdateIndex branchref + forceUpdateIndex jl branchref {- When there are journalled changes - as well as the branch being updated, - a commit needs to be done. -} @@ -160,14 +160,14 @@ updateTo pairs = do <$> getLocal transitionsLog unless (null branches) $ do showSideAction merge_desc - mergeIndex refs + mergeIndex jl refs let commitrefs = nub $ fullname:refs unlessM (handleTransitions jl localtransitions commitrefs) $ do ff <- if dirty then return False else inRepo $ Git.Branch.fastForward fullname refs if ff - then updateIndex branchref + then updateIndex jl branchref else commitBranch jl branchref merge_desc commitrefs liftIO cleanjournal @@ -240,7 +240,7 @@ commitBranch jl branchref message parents = do commitBranch' jl branchref message parents commitBranch' :: JournalLocked -> Git.Ref -> String -> [Git.Ref] -> Annex () commitBranch' jl branchref message parents = do - updateIndex branchref + updateIndex jl branchref committedref <- inRepo $ Git.Branch.commit message fullname parents setIndexSha committedref parentrefs <- commitparents <$> catObject committedref @@ -264,7 +264,7 @@ commitBranch' jl branchref message parents = do {- To recover from the race, union merge the lost refs - into the index, and recommit on top of the bad commit. -} fixrace committedref lostrefs = do - mergeIndex lostrefs + mergeIndex jl lostrefs commitBranch jl committedref racemessage [committedref] racemessage = message ++ " (recovery from race)" @@ -297,11 +297,27 @@ genIndex g = Git.UpdateIndex.streamUpdateIndex g {- Merges the specified refs into the index. - Any changes staged in the index will be preserved. -} -mergeIndex :: [Git.Ref] -> Annex () -mergeIndex branches = do +mergeIndex :: JournalLocked -> [Git.Ref] -> Annex () +mergeIndex jl branches = do + prepareModifyIndex jl h <- catFileHandle inRepo $ \g -> Git.UnionMerge.mergeIndex h g branches +{- Removes any stale git lock file, to avoid git falling over when + - updating the index. + - + - Since all modifications of the index are performed inside this module, + - and only when the journal is locked, the fact that the journal has to be + - locked when this is called ensures that no other process is currently + - modifying the index. So any index.lock file must be stale, caused + - by git running when the system crashed, or the repository's disk was + - removed, etc. + -} +prepareModifyIndex :: JournalLocked -> Annex () +prepareModifyIndex _jl = do + index <- fromRepo gitAnnexIndex + void $ liftIO $ tryIO $ removeFile $ index ++ ".lock" + {- Runs an action using the branch's index file. -} withIndex :: Annex a -> Annex a withIndex = withIndex' False @@ -339,13 +355,13 @@ withIndex' bootstrapping a = do - Compares the ref stored in the lock file with the current - ref of the branch to see if an update is needed. -} -updateIndex :: Git.Ref -> Annex () -updateIndex branchref = whenM (needUpdateIndex branchref) $ - forceUpdateIndex branchref +updateIndex :: JournalLocked -> Git.Ref -> Annex () +updateIndex jl branchref = whenM (needUpdateIndex branchref) $ + forceUpdateIndex jl branchref -forceUpdateIndex :: Git.Ref -> Annex () -forceUpdateIndex branchref = do - withIndex $ mergeIndex [fullname] +forceUpdateIndex :: JournalLocked -> Git.Ref -> Annex () +forceUpdateIndex jl branchref = do + withIndex $ mergeIndex jl [fullname] setIndexSha branchref {- Checks if the index needs to be updated. -} @@ -366,9 +382,18 @@ setIndexSha ref = do {- Stages the journal into the index and returns an action that will - clean up the staged journal files, which should only be run once - - the index has been committed to the branch. -} + - the index has been committed to the branch. + - + - Before staging, this removes any existing git index file lock. + - This is safe to do because stageJournal is the only thing that + - modifies this index file, and only one can run at a time, because + - the journal is locked. So any existing git index file lock must be + - stale, and the journal must contain any data that was in the process + - of being written to the index file when it crashed. + -} stageJournal :: JournalLocked -> Annex (IO ()) stageJournal jl = withIndex $ do + prepareModifyIndex jl g <- gitRepo let dir = gitAnnexJournalDir g fs <- getJournalFiles jl @@ -448,6 +473,7 @@ performTransitionsLocked jl ts neednewlocalbranch transitionedrefs = do -- for the head branch. Flush any such changes. Annex.Queue.flush withIndex $ do + prepareModifyIndex jl run $ mapMaybe getTransitionCalculator $ transitionList ts Annex.Queue.flush if neednewlocalbranch diff --git a/debian/changelog b/debian/changelog index b95a2dc58..950b5715b 100644 --- a/debian/changelog +++ b/debian/changelog @@ -1,3 +1,11 @@ +git-annex (4.20131003) UNRELEASED; urgency=low + + * Automatically and safely detect and recover from dangling + .git/annex/index.lock files, which would prevent git from + committing to the git-annex branch, eg after a crash. + + -- Joey Hess <joeyh@debian.org> Thu, 03 Oct 2013 15:41:24 -0400 + git-annex (4.20131002) unstable; urgency=low * Note that the layout of gcrypt repositories has changed, and |