toward SafeDropProof expiry checking

Added Maybe POSIXTime to SafeDropProof, which gets set when the proof is
based on a LockedCopy. If there are several LockedCopies, it uses the
closest expiry time. That is not optimal, it may be that the proof
expires based on one LockedCopy but another one has not expired. But
that seems unlikely to really happen, and anyway the user can just
re-run a drop if it fails due to expiry.

Pass the SafeDropProof to removeKey, which is responsible for checking
it for expiry in situations where that could be a problem. Which really
only means in Remote.Git.

Made Remote.Git check expiry when dropping from a local remote.

Checking expiry when dropping from a P2P remote is not yet implemented.
P2P.Protocol.remove has SafeDropProof plumbed through to it for that
purpose.

Fixing the remaining 2 build warnings should complete this work.

Note that the use of a POSIXTime here means that if the clock gets set
forward while git-annex is in the middle of a drop, it may say that
dropping took too long. That seems ok. Less ok is that if the clock gets
turned back a sufficient amount (eg 5 minutes), proof expiry won't be
noticed. It might be better to use the Monotonic clock, but that doesn't
advance when a laptop is suspended, and while there is the linux
Boottime clock, that is not available on other systems. Perhaps a
combination of POSIXTime and the Monotonic clock could detect laptop
suspension and also detect clock being turned back?

There is a potential future flag day where
p2pDefaultLockContentRetentionDuration is not assumed, but is probed
using the P2P protocol, and peers that don't support it can no longer
produce a LockedCopy. Until that happens, when git-annex is
communicating with older peers there is a risk of data loss when
a ssh connection closes during LOCKCONTENT.
This commit is contained in:
Joey Hess 2024-07-04 12:23:46 -04:00
parent 98dbfb6bbd
commit 1243af4a18
No known key found for this signature in database
GPG key ID: DB12DB0FF05F8F38
39 changed files with 274 additions and 123 deletions

View file

@ -141,7 +141,7 @@ lockContentShared key mduration a = do
ifM (inAnnex key)
( do
u <- getUUID
withVerifiedCopy LockedCopy u (return True) a
withVerifiedCopy LockedCopy u (return (Right True)) a
, notpresent
)
where

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@ -29,6 +29,7 @@ module Annex.NumCopies (
import Annex.Common
import qualified Annex
import Annex.SafeDropProof
import Types.NumCopies
import Logs.NumCopies
import Logs.Trust
@ -227,6 +228,10 @@ data UnVerifiedCopy = UnVerifiedRemote Remote | UnVerifiedHere
{- Verifies that enough copies of a key exist among the listed remotes,
- to safely drop it, running an action with a proof if so, and
- printing an informative message if not.
-
- Note that the proof is checked to still be valid at the current time
- before running the action, but when dropping the key may take some time,
- the proof's time may need to be checked again.
-}
verifyEnoughCopiesToDrop
:: String -- message to print when there are no known locations
@ -246,14 +251,14 @@ verifyEnoughCopiesToDrop nolocmsg key dropfrom removallock neednum needmin skip
where
helper bad missing have [] lockunsupported =
liftIO (mkSafeDropProof neednum needmin have removallock) >>= \case
Right proof -> dropaction proof
Right proof -> checkprooftime proof
Left stillhave -> do
notEnoughCopies key dropfrom neednum needmin stillhave (skip++missing) bad nolocmsg lockunsupported
nodropaction
helper bad missing have (c:cs) lockunsupported
| isSafeDrop neednum needmin have removallock =
liftIO (mkSafeDropProof neednum needmin have removallock) >>= \case
Right proof -> dropaction proof
Right proof -> checkprooftime proof
Left stillhave -> helper bad missing stillhave (c:cs) lockunsupported
| otherwise = case c of
UnVerifiedHere -> lockContentShared key Nothing contverified
@ -295,6 +300,14 @@ verifyEnoughCopiesToDrop nolocmsg key dropfrom removallock neednum needmin skip
]
Nothing -> fallback
checkprooftime proof =
ifM (liftIO $ checkSafeDropProofEndTime (Just proof))
( dropaction proof
, do
safeDropProofExpired
nodropaction
)
data DropException = DropException SomeException
deriving (Typeable, Show)

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@ -96,7 +96,7 @@ proxySpecialRemote protoversion r ihdl ohdl owaitv endv = go
liftIO $ sendmessage FAILURE
go
Just (REMOVE k) -> do
tryNonAsync (Remote.removeKey r k) >>= \case
tryNonAsync (Remote.removeKey r Nothing k) >>= \case
Right () -> liftIO $ sendmessage SUCCESS
Left err -> liftIO $ propagateerror err
go

34
Annex/SafeDropProof.hs Normal file
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@ -0,0 +1,34 @@
{- git-annex safe drop proof
-
- Copyright 2014-2024 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE OverloadedStrings #-}
module Annex.SafeDropProof (
SafeDropProof,
safeDropProofEndTime,
safeDropProofExpired,
checkSafeDropProofEndTime,
) where
import Annex.Common
import Types.NumCopies
import Data.Time.Clock.POSIX
safeDropProofExpired :: Annex ()
safeDropProofExpired = do
showNote "unsafe"
showLongNote $ UnquotedString
"Dropping took too long, and locks on remotes may have expired."
checkSafeDropProofEndTime :: Maybe SafeDropProof -> IO Bool
checkSafeDropProofEndTime p = case safeDropProofEndTime =<< p of
Nothing -> return True
Just t -> do
now <- getPOSIXTime
return (t < now)

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@ -996,7 +996,7 @@ dropKey rmt k = tryNonAsync (dropKey' rmt k) >>= \case
dropKey' :: Remote -> Key -> Annex ()
dropKey' rmt k = getKeyExportLocations rmt k >>= \case
Nothing -> Remote.removeKey rmt k
Nothing -> Remote.removeKey rmt Nothing k
Just locs -> forM_ locs $ \loc ->
Remote.removeExport (Remote.exportActions rmt) k loc

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@ -151,7 +151,7 @@ performRemote pcc key afile numcopies mincopies remote ud = do
, "proof:"
, show proof
]
ok <- Remote.action (Remote.removeKey remote key)
ok <- Remote.action (Remote.removeKey remote proof key)
next $ cleanupRemote key remote ud ok
, stop
)

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@ -639,7 +639,7 @@ badContentRemote remote localcopy key = do
)
)
dropped <- tryNonAsync (Remote.removeKey remote key)
dropped <- tryNonAsync (Remote.removeKey remote Nothing key)
when (isRight dropped) $
Remote.logStatus remote key InfoMissing
return $ case (movedbad, dropped) of

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@ -296,23 +296,26 @@ fromPerform' present updatelocationlog src key afile = do
fromDrop :: Remote -> UUID -> DestStartedWithCopy -> Key -> AssociatedFile -> ([UnVerifiedCopy] -> [UnVerifiedCopy])-> CommandPerform
fromDrop src destuuid deststartedwithcopy key afile adjusttocheck =
willDropMakeItWorse (Remote.uuid src) destuuid deststartedwithcopy key afile >>= \case
DropAllowed -> dropremote "moved"
DropAllowed -> dropremote Nothing "moved"
DropCheckNumCopies -> do
(numcopies, mincopies) <- getSafestNumMinCopies afile key
(tocheck, verified) <- verifiableCopies key [Remote.uuid src]
verifyEnoughCopiesToDrop "" key (Just (Remote.uuid src)) Nothing numcopies mincopies [Remote.uuid src] verified
(adjusttocheck tocheck) (dropremote . showproof) faileddropremote
(adjusttocheck tocheck) dropremotewithproof faileddropremote
DropWorse -> faileddropremote
where
showproof proof = "proof: " ++ show proof
dropremote reason = do
dropremotewithproof proof =
dropremote (Just proof) (showproof proof)
dropremote mproof reason = do
fastDebug "Command.Move" $ unwords
[ "Dropping from remote"
, show src
, "(" ++ reason ++ ")"
]
ok <- Remote.action (Remote.removeKey src key)
ok <- Remote.action (Remote.removeKey src mproof key)
when ok $
logMoveCleanup deststartedwithcopy
next $ Command.Drop.cleanupRemote key src (Command.Drop.DroppingUnused False) ok

View file

@ -303,7 +303,7 @@ test runannex mkr mkk =
Right v -> return (True, v)
Left _ -> return (False, UnVerified)
store r k = Remote.storeKey r k (AssociatedFile Nothing) Nothing nullMeterUpdate
remove r k = Remote.removeKey r k
remove r k = Remote.removeKey r Nothing k
testExportTree :: RunAnnex -> Annex (Maybe Remote) -> Annex Key -> Annex Key -> [TestTree]
testExportTree runannex mkr mkk1 mkk2 =
@ -366,7 +366,7 @@ testExportTree runannex mkr mkk1 mkk2 =
testUnavailable :: RunAnnex -> Annex (Maybe Remote) -> Annex Key -> [TestTree]
testUnavailable runannex mkr mkk =
[ check isLeft "removeKey" $ \r k ->
Remote.removeKey r k
Remote.removeKey r Nothing k
, check isLeft "storeKey" $ \r k ->
Remote.storeKey r k (AssociatedFile Nothing) Nothing nullMeterUpdate
, check (`notElem` [Right True, Right False]) "checkPresent" $ \r k ->
@ -397,7 +397,7 @@ cleanup :: [Remote] -> [Key] -> Bool -> CommandCleanup
cleanup rs ks ok
| all Remote.readonly rs = return ok
| otherwise = do
forM_ rs $ \r -> forM_ ks (Remote.removeKey r)
forM_ rs $ \r -> forM_ ks (Remote.removeKey r Nothing)
forM_ ks $ \k -> lockContentForRemoval k noop removeAnnex
return ok

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@ -1,6 +1,6 @@
{- P2P protocol, Annex implementation
-
- Copyright 2016-2023 Joey Hess <id@joeyh.name>
- Copyright 2016-2024 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
@ -23,7 +23,6 @@ import P2P.IO
import Logs.Location
import Types.NumCopies
import Utility.Metered
import Utility.HumanTime
import Utility.MonotonicClock
import Annex.Verify
@ -135,7 +134,7 @@ runLocal runst runner a = case a of
Left e -> return $ Left $ ProtoFailureException e
Right result -> runner (next result)
TryLockContent k protoaction next -> do
v <- tryNonAsync $ lockContentShared k (Just (Duration (60*10))) $ \verifiedcopy ->
v <- tryNonAsync $ lockContentShared k (Just p2pDefaultLockContentRetentionDuration) $ \verifiedcopy ->
case verifiedcopy of
LockedCopy _ -> runner (protoaction True)
_ -> runner (protoaction False)

View file

@ -29,6 +29,7 @@ import Utility.FileSystemEncoding
import Utility.MonotonicClock
import Git.FilePath
import Annex.ChangedRefs (ChangedRefs)
import Types.NumCopies
import Control.Monad
import Control.Monad.Free
@ -395,8 +396,8 @@ lockContentWhile runproto key a = bracket setup cleanup a
cleanup True = runproto () $ net $ sendMessage UNLOCKCONTENT
cleanup False = return ()
remove :: Key -> Proto (Either String Bool, Maybe [UUID])
remove key = do
remove :: Maybe SafeDropProof -> Key -> Proto (Either String Bool, Maybe [UUID])
remove proof key = do
net $ sendMessage (REMOVE key)
checkSuccessFailurePlus

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@ -210,7 +210,7 @@ retrieve' serial src dest =
]
remove :: AndroidSerial -> AndroidPath -> Remover
remove serial adir k =
remove serial adir _proof k =
unlessM (remove' serial (androidLocation adir k)) $
giveup "adb failed"

View file

@ -121,8 +121,8 @@ downloadKey key _file dest p _ = do
uploadKey :: Key -> AssociatedFile -> Maybe FilePath -> MeterUpdate -> Annex ()
uploadKey _ _ _ _ = giveup "upload to bittorrent not supported"
dropKey :: Key -> Annex ()
dropKey k = mapM_ (setUrlMissing k) =<< getBitTorrentUrls k
dropKey :: Maybe SafeDropProof -> Key -> Annex ()
dropKey _ k = mapM_ (setUrlMissing k) =<< getBitTorrentUrls k
{- We punt and don't try to check if a torrent has enough seeders
- with all the pieces etc. That would be quite hard.. and even if

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@ -210,7 +210,7 @@ retrieve r buprepo = byteRetriever $ \k sink -> lockBup True r $ do
- We can, however, remove the git branch that bup created for the key.
-}
remove :: BupRepo -> Remover
remove buprepo k = do
remove buprepo _proof k = do
go =<< liftIO (bup2GitRemote buprepo)
warning "content cannot be completely removed from bup remote"
where

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@ -180,7 +180,7 @@ retrieve ddarrepo = byteRetriever $ \k sink -> do
go _ _ _ = error "internal"
remove :: DdarRepo -> Remover
remove ddarrepo key = do
remove ddarrepo _proof key = do
(cmd, params) <- ddarRemoteCall NoConsumeStdin ddarrepo 'd'
[Param $ serializeKey key]
unlessM (liftIO $ boolSystem cmd params) $

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@ -270,7 +270,7 @@ retrieveKeyFileCheapM _ _ = Nothing
#endif
removeKeyM :: RawFilePath -> Remover
removeKeyM d k = liftIO $ removeDirGeneric True
removeKeyM d _proof k = liftIO $ removeDirGeneric True
(fromRawFilePath d)
(fromRawFilePath (storeDir d k))

View file

@ -259,7 +259,7 @@ retrieveKeyFileM external = fileRetriever $ \d k p ->
_ -> Nothing
removeKeyM :: External -> Remover
removeKeyM external k = either giveup return =<< go
removeKeyM external _proof k = either giveup return =<< go
where
go = handleRequestKey external REMOVE k Nothing $ \resp ->
case resp of

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@ -432,12 +432,12 @@ retrieve' repo r rsyncopts accessmethod
retrieversync = fileRetriever $ Remote.Rsync.retrieve rsyncopts
remove :: Remote -> Remote.Rsync.RsyncOpts -> AccessMethod -> Remover
remove r rsyncopts accessmethod k = do
remove r rsyncopts accessmethod proof k = do
repo <- getRepo r
remove' repo r rsyncopts accessmethod k
remove' repo r rsyncopts accessmethod proof k
remove' :: Git.Repo -> Remote -> Remote.Rsync.RsyncOpts -> AccessMethod -> Remover
remove' repo r rsyncopts accessmethod k
remove' repo r rsyncopts accessmethod proof k
| not $ Git.repoIsUrl repo = guardUsable repo (giveup "cannot access remote") $
liftIO $ Remote.Directory.removeDirGeneric True
(gCryptTopDir repo)
@ -446,8 +446,8 @@ remove' repo r rsyncopts accessmethod k
| accessmethod == AccessRsyncOverSsh = removersync
| otherwise = unsupportedUrl
where
removersync = Remote.Rsync.remove rsyncopts k
removeshell = Ssh.dropKey repo k
removersync = Remote.Rsync.remove rsyncopts proof k
removeshell = Ssh.dropKey repo proof k
checkKey :: Remote -> Remote.Rsync.RsyncOpts -> AccessMethod -> CheckPresent
checkKey r rsyncopts accessmethod k = do

View file

@ -61,6 +61,7 @@ import P2P.Address
import Annex.Path
import Creds
import Types.NumCopies
import Annex.SafeDropProof
import Types.ProposedAccepted
import Annex.Action
import Messages.Progress
@ -437,26 +438,43 @@ keyUrls gc repo r key = map tourl locs'
#endif
remoteconfig = gitconfig r
dropKey :: Remote -> State -> Key -> Annex ()
dropKey r st key = do
dropKey :: Remote -> State -> Maybe SafeDropProof -> Key -> Annex ()
dropKey r st proof key = do
repo <- getRepo r
dropKey' repo r st key
dropKey' repo r st proof key
dropKey' :: Git.Repo -> Remote -> State -> Key -> Annex ()
dropKey' repo r st@(State connpool duc _ _ _) key
dropKey' :: Git.Repo -> Remote -> State -> Maybe SafeDropProof -> Key -> Annex ()
dropKey' repo r st@(State connpool duc _ _ _) proof key
| not $ Git.repoIsUrl repo = ifM duc
( guardUsable repo (giveup "cannot access remote") $
commitOnCleanup repo r st $ onLocalFast st $ do
whenM (Annex.Content.inAnnex key) $ do
let cleanup = logStatus key InfoMissing
Annex.Content.lockContentForRemoval key cleanup $ \lock -> do
Annex.Content.removeAnnex lock
cleanup
( guardUsable repo (giveup "cannot access remote") removelocal
, giveup "remote does not have expected annex.uuid value"
)
| Git.repoIsHttp repo = giveup "dropping from http remote not supported"
| otherwise = P2PHelper.remove (uuid r)
(Ssh.runProto r connpool (return (Right False, Nothing))) key
| otherwise = P2PHelper.remove (uuid r) p2prunner proof key
where
p2prunner = Ssh.runProto r connpool (return (Right False, Nothing))
-- It could take a long time to eg, automount a drive containing
-- the repo, so check the proof for expiry again after locking the
-- content for removal.
removelocal = do
proofunexpired <- commitOnCleanup repo r st $ onLocalFast st $ do
ifM (Annex.Content.inAnnex key)
( do
let cleanup = do
logStatus key InfoMissing
return True
Annex.Content.lockContentForRemoval key cleanup $ \lock ->
ifM (liftIO $ checkSafeDropProofEndTime proof)
( do
Annex.Content.removeAnnex lock
cleanup
, return False
)
, return True
)
unless proofunexpired
safeDropProofExpired
lockKey :: Remote -> State -> Key -> (VerifiedCopy -> Annex r) -> Annex r
lockKey r st key callback = do

View file

@ -504,7 +504,7 @@ retrieve rs h = fileRetriever' $ \dest k p iv -> getLFSEndpoint LFS.RequestDownl
lockKey :: Remote -> RemoteStateHandle -> TVar LFSHandle -> Key -> (VerifiedCopy -> Annex a) -> Annex a
lockKey r rs h key callback =
ifM (checkKey rs h key)
( withVerifiedCopy LockedCopy (uuid r) (return True) callback
( withVerifiedCopy LockedCopy (uuid r) (return (Right True)) callback
, giveup $ "content seems to be missing from " ++ name r
)

View file

@ -214,7 +214,7 @@ retrieve' r k sink = go =<< glacierEnv c gc u
go' _ _ = error "internal"
remove :: Remote -> Remover
remove r k = unlessM go $
remove r _proof k = unlessM go $
giveup "removal from glacier failed"
where
go = glacierAction r

View file

@ -226,10 +226,10 @@ seekResume h encryptor chunkkeys checker = do
-
- This action may be called on a chunked key. It will simply remove it.
-}
removeChunks :: Remover -> UUID -> ChunkConfig -> EncKey -> Key -> Annex ()
removeChunks remover u chunkconfig encryptor k = do
removeChunks :: Remover -> UUID -> ChunkConfig -> EncKey -> Maybe SafeDropProof -> Key -> Annex ()
removeChunks remover u chunkconfig encryptor proof k = do
ls <- map chunkKeyList <$> chunkKeys u chunkconfig k
mapM_ (remover . encryptor) (concat ls)
mapM_ (remover proof . encryptor) (concat ls)
let chunksizes = catMaybes $ map (fromKey keyChunkSize <=< headMaybe) ls
forM_ chunksizes $ chunksRemoved u k . FixedSizeChunks . fromIntegral

View file

@ -41,7 +41,8 @@ addHooks' r starthook stophook = r'
, retrieveKeyFileCheap = case retrieveKeyFileCheap r of
Just a -> Just $ \k af f -> wrapper $ a k af f
Nothing -> Nothing
, removeKey = wrapper . removeKey r
, removeKey = \proof k ->
wrapper $ removeKey r proof k
, checkPresent = wrapper . checkPresent r
}
where

View file

@ -21,8 +21,10 @@ import Types.NumCopies
import Annex.Verify
import Logs.Location
import Utility.SafeOutput
import Utility.HumanTime
import Control.Concurrent
import Data.Time.Clock.POSIX
-- Runs a Proto action using a connection it sets up.
type ProtoRunner a = P2P.Proto a -> Annex (Maybe a)
@ -60,8 +62,8 @@ retrieve gc runner k af dest p verifyconfig = do
Just (False, _) -> giveup "Transfer failed"
Nothing -> remoteUnavail
remove :: UUID -> ProtoRunner (Either String Bool, Maybe [UUID]) -> Key -> Annex ()
remove remoteuuid runner k = runner (P2P.remove k) >>= \case
remove :: UUID -> ProtoRunner (Either String Bool, Maybe [UUID]) -> Maybe SafeDropProof -> Key -> Annex ()
remove remoteuuid runner proof k = runner (P2P.remove proof k) >>= \case
Just (Right True, alsoremoveduuids) -> note alsoremoveduuids
Just (Right False, alsoremoveduuids) -> do
note alsoremoveduuids
@ -94,18 +96,23 @@ checkpresent runner k =
-}
lock :: WithConn a c -> ProtoConnRunner c -> UUID -> Key -> (VerifiedCopy -> Annex a) -> Annex a
lock withconn connrunner u k callback = withconn $ \conn -> do
starttime <- liftIO getPOSIXTime
connv <- liftIO $ newMVar conn
let runproto d p = do
c <- liftIO $ takeMVar connv
(c', mr) <- connrunner p c
liftIO $ putMVar connv c'
return (fromMaybe d mr)
r <- P2P.lockContentWhile runproto k go
r <- P2P.lockContentWhile runproto k (go starttime)
conn' <- liftIO $ takeMVar connv
return (conn', r)
where
go False = giveup "can't lock content"
go True = withVerifiedCopy LockedCopy u (return True) callback
go _ False = giveup "can't lock content"
go starttime True = do
let check = return $ Left $ starttime + retentionduration
withVerifiedCopy LockedCopy u check callback
retentionduration = fromIntegral $
durationSeconds p2pDefaultLockContentRetentionDuration
remoteUnavail :: a
remoteUnavail = giveup "can't connect to remote"

View file

@ -47,8 +47,8 @@ adjustReadOnly r
readonlyStoreKey :: Key -> AssociatedFile -> Maybe FilePath -> MeterUpdate -> Annex ()
readonlyStoreKey _ _ _ _ = readonlyFail
readonlyRemoveKey :: Key -> Annex ()
readonlyRemoveKey _ = readonlyFail
readonlyRemoveKey :: Maybe SafeDropProof -> Key -> Annex ()
readonlyRemoveKey _ _ = readonlyFail
readonlyStorer :: Storer
readonlyStorer _ _ _ = readonlyFail

View file

@ -138,8 +138,8 @@ storeKeyDummy :: Key -> AssociatedFile -> Maybe FilePath -> MeterUpdate -> Annex
storeKeyDummy _ _ _ _ = error "missing storeKey implementation"
retrieveKeyFileDummy :: Key -> AssociatedFile -> FilePath -> MeterUpdate -> VerifyConfig -> Annex Verification
retrieveKeyFileDummy _ _ _ _ _ = error "missing retrieveKeyFile implementation"
removeKeyDummy :: Key -> Annex ()
removeKeyDummy _ = error "missing removeKey implementation"
removeKeyDummy :: Maybe SafeDropProof -> Key -> Annex ()
removeKeyDummy _ _ = error "missing removeKey implementation"
checkPresentDummy :: Key -> Annex Bool
checkPresentDummy _ = error "missing checkPresent implementation"
@ -197,7 +197,7 @@ specialRemote' cfg c storer retriever remover checkpresent baser = encr
, retrievalSecurityPolicy = if isencrypted
then mkRetrievalVerifiableKeysSecure (gitconfig baser)
else retrievalSecurityPolicy baser
, removeKey = \k -> cip >>= removeKeyGen k
, removeKey = \k proof -> cip >>= removeKeyGen k proof
, checkPresent = \k -> cip >>= checkPresentGen k
, cost = if isencrypted
then cost baser + encryptedRemoteCostAdj
@ -227,7 +227,7 @@ specialRemote' cfg c storer retriever remover checkpresent baser = encr
storeChunks (uuid baser) chunkconfig enck k src p'
enc encr storer checkpresent
where
rollback = void $ removeKey encr k
rollback = void $ removeKey encr Nothing k
enck = maybe id snd enc
-- call retriever to get chunks; decrypt them; stream to dest file
@ -238,8 +238,8 @@ specialRemote' cfg c storer retriever remover checkpresent baser = encr
where
enck = maybe id snd enc
removeKeyGen k enc =
removeChunks remover (uuid baser) chunkconfig enck k
removeKeyGen proof k enc =
removeChunks remover (uuid baser) chunkconfig enck proof k
where
enck = maybe id snd enc

View file

@ -105,13 +105,17 @@ inAnnex r k = onRemote NoConsumeStdin r (runcheck, cantCheck r) "inannex"
dispatch (ExitFailure 1) = return False
dispatch _ = cantCheck r
{- Removes a key from a remote. -}
dropKey :: Git.Repo -> Key -> Annex ()
dropKey r key = unlessM (dropKey' r key) $
{- Removes a key from a remote using the legacy git-annex-shell dropkey,
- rather than the P2P protocol.
-
- The proof is not checked for expire on the remote, so this should only
- be used by remotes that do not have lockContent return a LockedCopy. -}
dropKey :: Git.Repo -> Maybe SafeDropProof -> Key -> Annex ()
dropKey r proof key = unlessM (dropKey' r proof key) $
giveup "unable to remove key from remote"
dropKey' :: Git.Repo -> Key -> Annex Bool
dropKey' r key = onRemote NoConsumeStdin r (\f p -> liftIO (boolSystem f p), return False) "dropkey"
dropKey' :: Git.Repo -> Maybe SafeDropProof -> Key -> Annex Bool
dropKey' r _proof key = onRemote NoConsumeStdin r (\f p -> liftIO (boolSystem f p), return False) "dropkey"
[ Param "--quiet", Param "--force"
, Param $ serializeKey key
]

View file

@ -166,7 +166,7 @@ retrieve h = fileRetriever $ \d k _p ->
giveup "failed to retrieve content"
remove :: HookName -> Remover
remove h k =
remove h _proof k =
unlessM (runHook' h "remove" k Nothing $ return True) $
giveup "failed to remove content"

View file

@ -265,7 +265,7 @@ retrieveCheap o k _af f = ifM (preseedTmp k f)
)
remove :: RsyncOpts -> Remover
remove o k = removeGeneric o includes
remove o _proof k = removeGeneric o includes
where
includes = concatMap use dirHashes
use h = let dir = fromRawFilePath (h def k) in

View file

@ -449,7 +449,7 @@ retrieveHelper' h f p iv req = liftIO $ runResourceT $ do
Url.sinkResponseFile p iv zeroBytesProcessed f WriteMode rsp
remove :: S3HandleVar -> Remote -> S3Info -> Remover
remove hv r info k = withS3HandleOrFail (uuid r) hv $ \h -> do
remove hv r info _proof k = withS3HandleOrFail (uuid r) hv $ \h -> do
S3.DeleteObjectResponse <- liftIO $ runResourceT $ sendS3Handle h $
S3.DeleteObject (T.pack $ bucketObject info k) (bucket info)
return ()
@ -462,7 +462,7 @@ lockContentS3 hv r rs c info
| versioning info = Just $ \k callback -> do
checkVersioning info rs k
ifM (checkKey hv r rs c info k)
( withVerifiedCopy LockedCopy (uuid r) (return True) callback
( withVerifiedCopy LockedCopy (uuid r) (return (Right True)) callback
, giveup $ "content seems to be missing from " ++ name r ++ " despite S3 versioning being enabled"
)
| otherwise = Nothing

View file

@ -155,8 +155,8 @@ retrieve rs hdl k _f d _p _ = do
go (Just cap) = unlessM (liftIO $ requestTahoe hdl "get" [Param cap, File d]) $
giveup "tahoe failed to reteieve content"
remove :: Key -> Annex ()
remove _k = giveup "content cannot be removed from tahoe remote"
remove :: Maybe SafeDropProof -> Key -> Annex ()
remove _ _ = giveup "content cannot be removed from tahoe remote"
-- Since content cannot be removed from tahoe (by git-annex),
-- nothing needs to be done to lock content there, except for checking that
@ -164,7 +164,7 @@ remove _k = giveup "content cannot be removed from tahoe remote"
lockKey :: UUID -> RemoteStateHandle -> TahoeHandle -> Key -> (VerifiedCopy -> Annex a) -> Annex a
lockKey u rs hrl k callback =
ifM (checkKey rs hrl k)
( withVerifiedCopy LockedCopy u (return True) callback
( withVerifiedCopy LockedCopy u (return (Right True)) callback
, giveup $ "content seems to be missing from tahoe remote"
)

View file

@ -184,8 +184,8 @@ downloadKey urlincludeexclude key _af dest p vc =
uploadKey :: Key -> AssociatedFile -> Maybe FilePath -> MeterUpdate -> Annex ()
uploadKey _ _ _ _ = giveup "upload to web not supported"
dropKey :: UrlIncludeExclude -> Key -> Annex ()
dropKey urlincludeexclude k = mapM_ (setUrlMissing k) =<< getWebUrls' urlincludeexclude k
dropKey :: UrlIncludeExclude -> Maybe SafeDropProof -> Key -> Annex ()
dropKey urlincludeexclude _proof k = mapM_ (setUrlMissing k) =<< getWebUrls' urlincludeexclude k
checkKey :: UrlIncludeExclude -> Key -> Annex Bool
checkKey urlincludeexclude key = do

View file

@ -185,7 +185,7 @@ retrieveHelper loc d p iv = do
withContentM $ httpBodyRetriever d p iv
remove :: DavHandleVar -> Remover
remove hv k = withDavHandle hv $ \dav -> liftIO $ goDAV dav $
remove hv _proof k = withDavHandle hv $ \dav -> liftIO $ goDAV dav $
-- Delete the key's whole directory, including any
-- legacy chunked files, etc, in a single action.
removeHelper (keyDir k)

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@ -1,6 +1,6 @@
{- git-annex numcopies types
-
- Copyright 2014-2022 Joey Hess <id@joeyh.name>
- Copyright 2014-2024 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
@ -22,20 +22,24 @@ module Types.NumCopies (
withVerifiedCopy,
isSafeDrop,
SafeDropProof,
safeDropProofEndTime,
mkSafeDropProof,
ContentRemovalLock(..),
p2pDefaultLockContentRetentionDuration,
) where
import Types.UUID
import Types.Key
import Utility.Exception (bracketIO)
import Utility.Monad
import Utility.HumanTime
import qualified Data.Map as M
import Data.Either
import Control.Concurrent.MVar
import Control.Monad.Catch (MonadMask)
import Control.Monad.IO.Class (MonadIO)
import Control.Monad
import Data.Time.Clock.POSIX (POSIXTime)
newtype NumCopies = NumCopies Int
deriving (Ord, Eq, Show)
@ -77,14 +81,16 @@ data VerifiedCopy
| TrustedCopy V
{- The strongest proof of the existence of a copy.
- Until its associated action is called to unlock it,
- or connection with a remote repository is lost,
- the copy is locked in the repository and is guaranteed
- not to be removed by any git-annex process. -}
- not to be removed by any git-annex process. Use
- checkVerifiedCopy to detect loss of connection. -}
| LockedCopy V
deriving (Show)
data V = V
{ _getUUID :: UUID
, _checkVerifiedCopy :: IO Bool
, _checkVerifiedCopy :: IO (Either POSIXTime Bool)
, _invalidateVerifiedCopy :: IO ()
}
@ -99,8 +105,19 @@ toV (TrustedCopy v) = v
toV (RecentlyVerifiedCopy v) = v
toV (LockedCopy v) = v
-- Checks that it's still valid.
checkVerifiedCopy :: VerifiedCopy -> IO Bool
-- Checks that the VerifiedCopy is still valid.
--
-- Invalidation of the VerifiedCopy will make this return False.
--
-- When the key is being kept locked by a connection to a remote
-- repository, a detected loss of connection will make this
-- return False.
--
-- When the connection could possibly break without being detected
-- immediately, this will return a POSIXTime that is how long the
-- content is guaranteed to remain locked on the remote even if the
-- connection has broken.
checkVerifiedCopy :: VerifiedCopy -> IO (Either POSIXTime Bool)
checkVerifiedCopy = _checkVerifiedCopy . toV
invalidateVerifiedCopy :: VerifiedCopy -> IO ()
@ -119,15 +136,18 @@ deDupVerifiedCopies l = M.elems $
M.fromListWith strongestVerifiedCopy (zip (map toUUID l) l)
mkVerifiedCopy :: ToUUID u => (V -> VerifiedCopy) -> u -> VerifiedCopy
mkVerifiedCopy mk u = mk $ V (toUUID u) (return True) (return ())
mkVerifiedCopy mk u = mk $ V (toUUID u) (return (Right True)) (return ())
invalidatableVerifiedCopy :: ToUUID u => (V -> VerifiedCopy) -> u -> IO Bool -> IO VerifiedCopy
invalidatableVerifiedCopy :: ToUUID u => (V -> VerifiedCopy) -> u -> IO (Either POSIXTime Bool) -> IO VerifiedCopy
invalidatableVerifiedCopy mk u check = do
v <- newEmptyMVar
let invalidate = do
_ <- tryPutMVar v ()
return ()
let check' = isEmptyMVar v <&&> check
let check' = ifM (isEmptyMVar v)
( check
, pure (Right False)
)
return $ mk $ V (toUUID u) check' invalidate
-- Constructs a VerifiedCopy, and runs the action, ensuring that the
@ -136,7 +156,7 @@ withVerifiedCopy
:: (MonadMask m, MonadIO m, ToUUID u)
=> (V -> VerifiedCopy)
-> u
-> IO Bool
-> IO (Either POSIXTime Bool)
-> (VerifiedCopy -> m a)
-> m a
withVerifiedCopy mk u check = bracketIO setup cleanup
@ -155,13 +175,26 @@ withVerifiedCopy mk u check = bracketIO setup cleanup
- to fall below NumCopies, but it will never fall below MinCopies.
-}
isSafeDrop :: NumCopies -> MinCopies -> [VerifiedCopy] -> Maybe ContentRemovalLock -> Bool
isSafeDrop n m l lck = case safeDropAnalysis n m l lck of
UnsafeDrop -> False
SafeDrop -> True
SafeDropCheckTime -> True
data SafeDropAnalysis
= UnsafeDrop
| SafeDrop
| SafeDropCheckTime
safeDropAnalysis :: NumCopies -> MinCopies -> [VerifiedCopy] -> Maybe ContentRemovalLock -> SafeDropAnalysis
{- When a ContentRemovalLock is provided, the content is being
- dropped from the local repo. That lock will prevent other git repos
- that are concurrently dropping from using the local copy as a VerifiedCopy.
- So, no additional locking is needed; all we need is verifications
- of any kind of enough other copies of the content. -}
isSafeDrop (NumCopies n) (MinCopies m) l (Just (ContentRemovalLock _)) =
length (deDupVerifiedCopies l) >= max n m
safeDropAnalysis (NumCopies n) (MinCopies m) l (Just (ContentRemovalLock _)) =
if length (deDupVerifiedCopies l) >= max n m
then SafeDrop
else UnsafeDrop
{- Dropping from a remote repo.
-
- To guarantee MinCopies is never violated, at least that many LockedCopy
@ -174,27 +207,49 @@ isSafeDrop (NumCopies n) (MinCopies m) l (Just (ContentRemovalLock _)) =
- violated, this is the best that can be done without requiring that
- all special remotes support locking.
-}
isSafeDrop (NumCopies n) (MinCopies m) l Nothing
| n == 0 && m == 0 = True
| otherwise = and
[ length (deDupVerifiedCopies l) >= n
, length (filter fullVerification l) >= m
]
safeDropAnalysis (NumCopies n) (MinCopies m) l Nothing
| n == 0 && m == 0 = SafeDrop
| length (deDupVerifiedCopies l) >= n
&& length (filter fullVerification l) >= m =
SafeDropCheckTime
| otherwise = UnsafeDrop
fullVerification :: VerifiedCopy -> Bool
fullVerification (LockedCopy _) = True
fullVerification (TrustedCopy _) = True
fullVerification (RecentlyVerifiedCopy _) = False
-- A proof that it's currently safe to drop an object.
data SafeDropProof = SafeDropProof NumCopies MinCopies [VerifiedCopy] (Maybe ContentRemovalLock)
-- Content locked using the P2P protocol defaults to being retained,
-- still locked, for 10 minutes after a connection loss.
--
-- This is only the case since git-annex 10.20240704, but currently
-- this is used even for older remotes, to avoid a disruptive behavior
-- change when used with remotes running an old version of git-annex.
p2pDefaultLockContentRetentionDuration :: Duration
p2pDefaultLockContentRetentionDuration = Duration (60*10)
-- A proof that it's safe to drop an object.
--
-- It may only be safe up until a given POSIXTime.
data SafeDropProof = SafeDropProof NumCopies MinCopies [VerifiedCopy] (Maybe POSIXTime) (Maybe ContentRemovalLock)
deriving (Show)
safeDropProofEndTime :: SafeDropProof -> Maybe POSIXTime
safeDropProofEndTime (SafeDropProof _ _ _ t _) = t
-- Makes sure that none of the VerifiedCopies have become invalidated
-- before constructing proof.
-- before constructing the proof.
mkSafeDropProof :: NumCopies -> MinCopies -> [VerifiedCopy] -> Maybe ContentRemovalLock -> IO (Either [VerifiedCopy] SafeDropProof)
mkSafeDropProof need mincopies have removallock = do
stillhave <- filterM checkVerifiedCopy have
return $ if isSafeDrop need mincopies stillhave removallock
then Right (SafeDropProof need mincopies stillhave removallock)
else Left stillhave
l <- mapM checkVerifiedCopy have
let stillhave = map fst $
filter (either (const True) id . snd) (zip have l)
return $ case safeDropAnalysis need mincopies stillhave removallock of
SafeDrop -> Right $
SafeDropProof need mincopies stillhave Nothing removallock
SafeDropCheckTime -> Right $
let endtime = case lefts l of
[] -> Nothing
ts -> Just (minimum ts)
in SafeDropProof need mincopies stillhave endtime removallock
UnsafeDrop -> Left stillhave

View file

@ -2,7 +2,7 @@
-
- Most things should not need this, using Types instead
-
- Copyright 2011-2021 Joey Hess <id@joeyh.name>
- Copyright 2011-2024 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
@ -25,6 +25,7 @@ module Types.Remote
, ExportActions(..)
, ImportActions(..)
, ByteSize
, SafeDropProof
)
where
@ -105,8 +106,14 @@ data RemoteA a = Remote
, retrievalSecurityPolicy :: RetrievalSecurityPolicy
-- Removes a key's contents (succeeds even the contents are not present)
-- Can throw exception if unable to access remote, or if remote
-- refuses to remove the content.
, removeKey :: Key -> a ()
-- refuses to remove the content, or if the proof is expired.
--
-- The proof is verified not to have expired shortly
-- before calling this. But, if the remote's lockContent returns
-- LockedCopy, the proof's expiry should be checked on the remote,
-- so that a delay in communicating with the remote does not
-- cause the removal to happen after the proof expires.
, removeKey :: Maybe SafeDropProof -> Key -> a ()
-- Uses locking to prevent removal of a key's contents,
-- thus producing a VerifiedCopy, which is passed to the callback.
-- If unable to lock, does not run the callback, and throws an

View file

@ -10,6 +10,7 @@
module Types.StoreRetrieve where
import Annex.Common
import Types.NumCopies
import Utility.Metered
import Utility.Hash (IncrementalVerifier)
@ -44,8 +45,9 @@ type Retriever = forall a.
-- Action that removes a Key's content from a remote.
-- Succeeds if key is already not present.
-- Throws an exception if the remote is not accessible.
type Remover = Key -> Annex ()
-- Throws an exception if the remote is not accessible
-- or the proof has expired.
type Remover = Maybe SafeDropProof -> Key -> Annex ()
-- Checks if a Key's content is present on a remote.
-- Throws an exception if the remote is not accessible.

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@ -115,8 +115,8 @@ the client sends:
The server responds with either SUCCESS or FAILURE.
The former indicates the content is locked. It will remain
locked until the connection is broken, or the client
sends:
locked until 10 minutes after the connection is broken, or until
the client sends:
UNLOCKCONTENT Key

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@ -29,18 +29,15 @@ It seems that LOCKCONTENT needs to guarantee that the content remains
locked for some amount of time. Then local git-annex would know it
has at most that long to drop the content. But it's the remote that's
dropping that really needs to know. So, extend the P2P protocol with a
PRE-REMOVE step. After receiving PRE-REMOVE N Key, a REMOVE of that key is only
allowed until N seconds later. Sending PRE-REMOVE first, followed by
LOCKCONTENT will guarantee the content remains locked for the full amount
of time.
REMOVE-BEFORE Timestamp Key and a GETTIMESTAMP.
How long? 10 minutes is arbitrary, but seems in the right ballpark. Since
this will cause drops to fail if they timeout sitting at a ssh password
prompt, it needs to be more than a few minutes. But making it too long, eg
an hour can result in content being stuck locked on a remote for a long
time, preventing a later legitimate drop. It could be made configurable, if
needed, by extending the P2P protocol so LOCKCONTENT was passed the amount
of time.
How long to lock for? 10 minutes is arbitrary, but seems in the right
ballpark. Since this will cause drops to fail if they timeout sitting at a
ssh password prompt, it needs to be more than a few minutes. But making it
too long, eg an hour can result in content being stuck locked on a remote
for a long time, preventing a later legitimate drop. It could be made
configurable, if needed, by extending the P2P protocol so LOCKCONTENT was
passed the amount of time.
Having lockContentWhile catch all exceptions and keep the content locked
for the time period won't work though. Systemd reaps processes on ssh
@ -111,3 +108,12 @@ out to each client, by calling GETTIMESTAMP again and applying the offsets
between the cluster's clock and each node's clock.
This approach would need to use a monotonic clock!
---
There is a potential future flag day where
p2pDefaultLockContentRetentionDuration is not assumed, but is probed
using the P2P protocol, and peers that don't support it can no longer
produce a LockedCopy. Until that happens, when git-annex is
communicating with older peers there is a risk of data loss when
a ssh connection closes during LOCKCONTENT.

View file

@ -555,6 +555,7 @@ Executable git-annex
Annex.Queue
Annex.ReplaceFile
Annex.RemoteTrackingBranch
Annex.SafeDropProof
Annex.SpecialRemote
Annex.SpecialRemote.Config
Annex.Ssh