git-annex/Command/Migrate.hs
Joey Hess 88a7fb5cbb
convert all applicable commands to new 2x faster annexed file seeking
This removes all calls to inAnnex, except for some involving --batch.
It may be that the batch code could get a similar speedup, but I don't
know if people habitually pass a huge number of files through --batch
that git-annex does not need to do anything to process, so I skipped it
for now.

A few calls to ifAnnexed remain, and might be worth doing more to
convert. In particular, Command.Sync has one that would probably speed
it up by a good amount.

(also removed some dead code from Command.Lock)
2020-07-10 15:45:38 -04:00

100 lines
3.2 KiB
Haskell

{- git-annex command
-
- Copyright 2011 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module Command.Migrate where
import Command
import Backend
import Types.Backend (canUpgradeKey, fastMigrate)
import Types.KeySource
import Annex.Content
import qualified Command.ReKey
import qualified Command.Fsck
import qualified Annex
import Logs.MetaData
import Logs.Web
import Utility.Metered
cmd :: Command
cmd = withGlobalOptions [annexedMatchingOptions] $
command "migrate" SectionUtility
"switch data to different backend"
paramPaths (withParams seek)
seek :: CmdParams -> CommandSeek
seek = withFilesInGitAnnex ww (commandAction' start)
<=< workTreeItems ww
where
ww = WarnUnmatchLsFiles
start :: RawFilePath -> Key -> CommandStart
start file key = do
forced <- Annex.getState Annex.force
v <- Backend.getBackend (fromRawFilePath file) key
case v of
Nothing -> stop
Just oldbackend -> do
exists <- inAnnex key
newbackend <- maybe defaultBackend return
=<< chooseBackend (fromRawFilePath file)
if (newbackend /= oldbackend || upgradableKey oldbackend key || forced) && exists
then starting "migrate" (mkActionItem (key, file)) $
perform file key oldbackend newbackend
else stop
{- Checks if a key is upgradable to a newer representation.
-
- Reasons for migration:
- - Ideally, all keys have file size metadata. Old keys may not.
- - Something has changed in the backend, such as a bug fix.
-}
upgradableKey :: Backend -> Key -> Bool
upgradableKey backend key = isNothing (fromKey keySize key) || backendupgradable
where
backendupgradable = maybe False (\a -> a key) (canUpgradeKey backend)
{- Store the old backend's key in the new backend
- The old backend's key is not dropped from it, because there may
- be other files still pointing at that key.
-
- To ensure that the data we have for the old key is valid, it's
- fscked here. First we generate the new key. This ensures that the
- data cannot get corrupted after the fsck but before the new key is
- generated.
-}
perform :: RawFilePath -> Key -> Backend -> Backend -> CommandPerform
perform file oldkey oldbackend newbackend = go =<< genkey (fastMigrate oldbackend)
where
go Nothing = stop
go (Just (newkey, knowngoodcontent))
| knowngoodcontent = finish newkey
| otherwise = stopUnless checkcontent $ finish newkey
checkcontent = Command.Fsck.checkBackend oldbackend oldkey Command.Fsck.KeyPresent afile
finish newkey = ifM (Command.ReKey.linkKey file oldkey newkey)
( do
_ <- copyMetaData oldkey newkey
-- If the old key had some associated urls, record them for
-- the new key as well.
urls <- getUrls oldkey
forM_ urls $ \url ->
setUrlPresent newkey url
next $ Command.ReKey.cleanup file oldkey newkey
, giveup "failed creating link from old to new key"
)
genkey Nothing = do
content <- calcRepo $ gitAnnexLocation oldkey
let source = KeySource
{ keyFilename = file
, contentLocation = content
, inodeCache = Nothing
}
newkey <- fst <$> genKey source nullMeterUpdate (Just newbackend)
return $ Just (newkey, False)
genkey (Just fm) = fm oldkey newbackend afile >>= \case
Just newkey -> return (Just (newkey, True))
Nothing -> genkey Nothing
afile = AssociatedFile (Just file)