{- git-annex transfers
-
- - Copyright 2012-2023 Joey Hess <id@joeyh.name>
+ - Copyright 2012-2024 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
where
go = do
info <- liftIO $ startTransferInfo afile
- (meter, tfile, createtfile, metervar) <- mkProgressUpdater t info
+ (tfile, lckfile, moldlckfile) <- fromRepo $ transferFileAndLockFile t
+ (meter, createtfile, metervar) <- mkProgressUpdater t info tfile
mode <- annexFileMode
- (lck, inprogress) <- prep tfile createtfile mode
+ (lck, inprogress) <- prep lckfile moldlckfile createtfile mode
if inprogress && not ignorelock
then do
warning "transfer already in progress, or unable to take transfer lock"
v <- retry 0 info metervar $
detectStallsAndSuggestConfig stalldetection metervar $
transferaction meter
- liftIO $ cleanup tfile lck
+ liftIO $ cleanup tfile lckfile moldlckfile lck
if observeBool v
then removeFailedTransfer t
else recordFailedTransfer t info
return v
- prep :: RawFilePath -> Annex () -> ModeSetter -> Annex (Maybe LockHandle, Bool)
+ prep :: RawFilePath -> Maybe RawFilePath -> Annex () -> ModeSetter -> Annex (Maybe (LockHandle, Maybe LockHandle), Bool)
#ifndef mingw32_HOST_OS
- prep tfile createtfile mode = catchPermissionDenied (const prepfailed) $ do
- let lck = transferLockFile tfile
- createAnnexDirectory $ P.takeDirectory lck
- tryLockExclusive (Just mode) lck >>= \case
+ prep lckfile moldlckfile createtfile mode = catchPermissionDenied (const prepfailed) $ do
+ createAnnexDirectory $ P.takeDirectory lckfile
+ tryLockExclusive (Just mode) lckfile >>= \case
Nothing -> return (Nothing, True)
-- Since the lock file is removed in cleanup,
-- there's a race where different processes
-- may have a deleted and a new version of the same
-- lock file open. checkSaneLock guards against
-- that.
- Just lockhandle -> ifM (checkSaneLock lck lockhandle)
- ( do
- createtfile
- return (Just lockhandle, False)
+ Just lockhandle -> ifM (checkSaneLock lckfile lockhandle)
+ ( case moldlckfile of
+ Nothing -> do
+ createtfile
+ return (Just (lockhandle, Nothing), False)
+ Just oldlckfile -> do
+ createAnnexDirectory $ P.takeDirectory oldlckfile
+ tryLockExclusive (Just mode) oldlckfile >>= \case
+ Nothing -> do
+ liftIO $ dropLock lockhandle
+ return (Nothing, True)
+ Just oldlockhandle -> ifM (checkSaneLock oldlckfile oldlockhandle)
+ ( do
+ createtfile
+ return (Just (lockhandle, Just oldlockhandle), False)
+ , do
+ liftIO $ dropLock oldlockhandle
+ liftIO $ dropLock lockhandle
+ return (Nothing, True)
+ )
, do
liftIO $ dropLock lockhandle
return (Nothing, True)
)
#else
- prep tfile createtfile _mode = catchPermissionDenied (const prepfailed) $ do
- let lck = transferLockFile tfile
- createAnnexDirectory $ P.takeDirectory lck
- catchMaybeIO (liftIO $ lockExclusive lck) >>= \case
- Nothing -> return (Nothing, False)
- Just Nothing -> return (Nothing, False)
- Just (Just lockhandle) -> do
- createtfile
- return (Just lockhandle, False)
+ prep lckfile moldlckfile createtfile _mode = catchPermissionDenied (const prepfailed) $ do
+ createAnnexDirectory $ P.takeDirectory lckfile
+ catchMaybeIO (liftIO $ lockExclusive lckfile) >>= \case
+ Just (Just lockhandle) -> case moldlckfile of
+ Nothing -> do
+ createtfile
+ return (Just (lockhandle, Nothing), False)
+ Just oldlckfile -> do
+ createAnnexDirectory $ P.takeDirectory oldlckfile
+ catchMaybeIO (liftIO $ lockExclusive oldlckfile) >>= \case
+ Just (Just oldlockhandle) -> do
+ createtfile
+ return (Just (lockhandle, Just oldlockhandle), False)
+ _ -> do
+ liftIO $ dropLock lockhandle
+ return (Nothing, False)
+ _ -> return (Nothing, False)
#endif
prepfailed = return (Nothing, False)
- cleanup _ Nothing = noop
- cleanup tfile (Just lockhandle) = do
- let lck = transferLockFile tfile
+ cleanup _ _ _ Nothing = noop
+ cleanup tfile lckfile moldlckfile (Just (lockhandle, moldlockhandle)) = do
void $ tryIO $ R.removeLink tfile
#ifndef mingw32_HOST_OS
- void $ tryIO $ R.removeLink lck
+ void $ tryIO $ R.removeLink lckfile
+ maybe noop (void . tryIO . R.removeLink) moldlckfile
+ maybe noop dropLock moldlockhandle
dropLock lockhandle
#else
{- Windows cannot delete the lockfile until the lock
- process that takes the lock before it's removed,
- so ignore failure to remove.
-}
+ maybe noop dropLock moldlockhandle
dropLock lockhandle
- void $ tryIO $ R.removeLink lck
+ void $ tryIO $ R.removeLink lckfile
+ maybe noop (void . tryIO . R.removeLink) moldlckfile
#endif
retry numretries oldinfo metervar run =
{- Otherwise, this code polls the upload progress
- by reading the transfer info file. -}
| otherwise = do
- let f = transferFile t g
+ let (f, _, _) = transferFileAndLockFile t g
mi <- liftIO $ catchDefaultIO Nothing $
readTransferInfoFile Nothing (fromRawFilePath f)
maybe noop (newsize t info . bytesComplete) mi
* Added dependency on unbounded-delays.
* reregisterurl: New command that can change an url from being
used by a special remote to being used by the web remote.
+ * Bugfix: While redundant concurrent transfers were already
+ prevented in most cases, it failed to prevent the case where
+ two different repositories were sending the same content to
+ the same repository.
-- Joey Hess <id@joeyh.name> Tue, 27 Feb 2024 13:07:10 -0400
{- git-annex transfer information files and lock files
-
- - Copyright 2012-2021 Joey Hess <id@joeyh.name>
+ - Copyright 2012-2024 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
<*> Just (fromMaybe 0 $ bytesComplete info)
{- Generates a callback that can be called as transfer progresses to update
- - the transfer info file. Also returns the file it'll be updating,
- - an action that sets up the file with appropriate permissions,
- - which should be run after locking the transfer lock file, but
- - before using the callback, and a TVar that can be used to read
- - the number of bytes processed so far. -}
-mkProgressUpdater :: Transfer -> TransferInfo -> Annex (MeterUpdate, RawFilePath, Annex (), TVar (Maybe BytesProcessed))
-mkProgressUpdater t info = do
- tfile <- fromRepo $ transferFile t
+ - the transfer info file. Also returns an action that sets up the file with
+ - appropriate permissions, which should be run after locking the transfer
+ - lock file, but before using the callback, and a TVar that can be used to
+ - read the number of bytes processed so far. -}
+mkProgressUpdater :: Transfer -> TransferInfo -> RawFilePath -> Annex (MeterUpdate, Annex (), TVar (Maybe BytesProcessed))
+mkProgressUpdater t info tfile = do
let createtfile = void $ tryNonAsync $ writeTransferInfoFile info tfile
tvar <- liftIO $ newTVarIO Nothing
loggedtvar <- liftIO $ newTVarIO 0
- return (liftIO . updater (fromRawFilePath tfile) tvar loggedtvar, tfile, createtfile, tvar)
+ return (liftIO . updater (fromRawFilePath tfile) tvar loggedtvar, createtfile, tvar)
where
- updater tfile tvar loggedtvar new = do
+ updater tfile' tvar loggedtvar new = do
old <- atomically $ swapTVar tvar (Just new)
let oldbytes = maybe 0 fromBytesProcessed old
let newbytes = fromBytesProcessed new
when (newbytes - oldbytes >= mindelta) $ do
let info' = info { bytesComplete = Just newbytes }
- _ <- tryIO $ updateTransferInfoFile info' tfile
+ _ <- tryIO $ updateTransferInfoFile info' tfile'
atomically $ writeTVar loggedtvar newbytes
{- The minimum change in bytesComplete that is worth
{- If a transfer is still running, returns its TransferInfo.
-
- If no transfer is running, attempts to clean up the stale
- - lock and info files. This can happen if a transfer process was
- - interrupted.
+ - lock and info files, which can be left behind when a transfer
+ - process was interrupted.
-}
checkTransfer :: Transfer -> Annex (Maybe TransferInfo)
checkTransfer t = debugLocks $ do
- tfile <- fromRepo $ transferFile t
- let lck = transferLockFile tfile
- let cleanstale = do
+ (tfile, lck, moldlck) <- fromRepo $ transferFileAndLockFile t
+ let deletestale = do
void $ tryIO $ R.removeLink tfile
void $ tryIO $ R.removeLink lck
+ maybe noop (void . tryIO . R.removeLink) moldlck
#ifndef mingw32_HOST_OS
v <- getLockStatus lck
- case v of
+ v' <- case (moldlck, v) of
+ (Nothing, _) -> pure v
+ (_, StatusLockedBy pid) -> pure (StatusLockedBy pid)
+ (Just oldlck, _) -> getLockStatus oldlck
+ case v' of
StatusLockedBy pid -> liftIO $ catchDefaultIO Nothing $
readTransferInfoFile (Just pid) (fromRawFilePath tfile)
_ -> do
- -- Take a non-blocking lock while deleting
- -- the stale lock file. Ignore failure
- -- due to permissions problems, races, etc.
- void $ tryIO $ do
- mode <- annexFileMode
- r <- tryLockExclusive (Just mode) lck
- case r of
- Just lockhandle -> liftIO $ do
- cleanstale
+ mode <- annexFileMode
+ -- Ignore failure due to permissions, races, etc.
+ void $ tryIO $ tryLockExclusive (Just mode) lck >>= \case
+ Just lockhandle -> case moldlck of
+ Nothing -> liftIO $ do
+ deletestale
dropLock lockhandle
- _ -> noop
+ Just oldlck -> tryLockExclusive (Just mode) oldlck >>= \case
+ Just oldlockhandle -> liftIO $ do
+ deletestale
+ dropLock oldlockhandle
+ dropLock lockhandle
+ Nothing -> liftIO $ dropLock lockhandle
+ Nothing -> noop
return Nothing
#else
v <- liftIO $ lockShared lck
failedtfile <- fromRepo $ failedTransferFile t
writeTransferInfoFile info failedtfile
-{- The transfer information file to use for a given Transfer. -}
-transferFile :: Transfer -> Git.Repo -> RawFilePath
-transferFile (Transfer direction u kd) r =
- transferDir direction r
- P.</> B8.filter (/= '/') (fromUUID u)
- P.</> keyFile (mkKey (const kd))
+{- The transfer information file and transfer lock file
+ - to use for a given Transfer.
+ -
+ - The transfer lock file used for an Upload includes the UUID.
+ - This allows multiple transfers of the same key to different remote
+ - repositories run at the same time, while preventing multiple
+ - transfers of the same key to the same remote repository.
+ -
+ - The transfer lock file used for a Download does not include the UUID.
+ - This prevents multiple transfers of the same key into the local
+ - repository at the same time.
+ -
+ - Since old versions of git-annex (10.20240227 and older) used to
+ - include the UUID in the transfer lock file for a Download, this also
+ - returns a second lock file for Downloads, which has to be locked
+ - in order to interoperate with the old git-annex processes.
+ - Lock order is the same as return value order.
+ - At some point in the future, when old git-annex processes are no longer
+ - a concern, this complication can be removed.
+ -}
+transferFileAndLockFile :: Transfer -> Git.Repo -> (RawFilePath, RawFilePath, Maybe RawFilePath)
+transferFileAndLockFile (Transfer direction u kd) r =
+ case direction of
+ Upload -> (transferfile, uuidlockfile, Nothing)
+ Download -> (transferfile, nouuidlockfile, Just uuidlockfile)
+ where
+ td = transferDir direction r
+ fu = B8.filter (/= '/') (fromUUID u)
+ kf = keyFile (mkKey (const kd))
+ lckkf = "lck." <> kf
+ transferfile = td P.</> fu P.</> kf
+ uuidlockfile = td P.</> fu P.</> lckkf
+ nouuidlockfile = td P.</> "lck" P.</> lckkf
{- The transfer information file to use to record a failed Transfer -}
failedTransferFile :: Transfer -> Git.Repo -> RawFilePath
failedTransferDir u direction r
P.</> keyFile (mkKey (const kd))
-{- The transfer lock file corresponding to a given transfer info file. -}
-transferLockFile :: RawFilePath -> RawFilePath
-transferLockFile infofile =
- let (d, f) = P.splitFileName infofile
- in P.combine d ("lck." <> f)
-
{- Parses a transfer information filename to a Transfer. -}
parseTransferFile :: FilePath -> Maybe Transfer
parseTransferFile file
(cd b; git-annex copy --to origin) &
(cd c; git-annex copy --to origin) &
+Also same happens when running `git-annex get --from` two different remotes
+concurrently in the same repo.
+
Aha... Looking at the code, this seems like a fundamental oversight.
The `transferFile` depends on the uuid of the remote being transfered
to/from, so there are two different ones in this case. And the transfer
behavior to break either, even if it would usually only break transiently.
Of course that could be avoided by keeping the current lock file, and
-adding a second level lock file.
+adding a second lock file. [[done]] this, with plans in
+[[todo/v11_changes]] to transition to use only the new lock file in
+the future.
--[[Joey]]
after upgrading to the repo version that enables this. Depending on the
timing of v11, this may need to be put in a v12 upgrade that is delayed
some amount of time (eg 1 year) after v11.
+
+* Avoid locking old transfer lock file. transferFileAndLockFile
+ currently returns two lock files for Download transfers,
+ and locking both of them is unncessary work, which is only needed to
+ interoperate with old git-annex versions that only lock the old lock file
+ and not the new one.
+
+ (Note that the old lock file should still be deleted when cleaning up the
+ new lock file, to make sure that all the old lock files get deleted.)
+
+ It would not be great if this change were made when a git-annex version
+ 10.20240227 or older was running in the repository. But it wouldn't be
+ the end of the world either, because the effect would be effectively
+ the same as the bug that the second transfer lock was added to fix.
+ Still, it would make sense to put this in a v12 upgrade that is delayed
+ some amount of time (eg 1 year) after v11.
projects / git-annex.git / commitdiff