git-annex/Command/Migrate.hs
Joey Hess f1b0a4b404 Use lower case hash directories for storing files on crippled filesystems, same as is already done for bare repositories.
* since this is a crippled filesystem anyway, git-annex doesn't use
  symlinks on it
* so there's no reason to use the mixed case hash directories that we're
  stuck using to avoid breaking everyone's symlinks to the content
* so we can do what is already done for all bare repos, and make non-bare
  repos on crippled filesystems use the all-lower case hash directories
* which are, happily, all 3 letters long, so they cannot conflict with
  mixed case hash directories
* so I was able to 100% fix this and even resuming `git annex add` in the
  test case will recover and it will all just work.
2013-04-04 15:46:33 -04:00

72 lines
2.1 KiB
Haskell

{- git-annex command
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Command.Migrate where
import Common.Annex
import Command
import Backend
import qualified Types.Key
import qualified Types.Backend
import Types.KeySource
import Annex.Content
import qualified Command.ReKey
import qualified Command.Fsck
def :: [Command]
def = [notDirect $
command "migrate" paramPaths seek
SectionUtility "switch data to different backend"]
seek :: [CommandSeek]
seek = [withFilesInGit $ whenAnnexed start]
start :: FilePath -> (Key, Backend) -> CommandStart
start file (key, oldbackend) = do
exists <- inAnnex key
newbackend <- choosebackend =<< chooseBackend file
if (newbackend /= oldbackend || upgradableKey oldbackend key) && exists
then do
showStart "migrate" file
next $ perform file key oldbackend newbackend
else stop
where
choosebackend Nothing = Prelude.head <$> orderedList
choosebackend (Just backend) = return backend
{- 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 (Types.Key.keySize key) || backendupgradable
where
backendupgradable = maybe False (\a -> a key)
(Types.Backend.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. -}
perform :: FilePath -> Key -> Backend -> Backend -> CommandPerform
perform file oldkey oldbackend newbackend = do
ifM (Command.Fsck.checkBackend oldbackend oldkey)
( maybe stop go =<< genkey
, stop
)
where
go newkey = stopUnless (Command.ReKey.linkKey oldkey newkey) $
next $ Command.ReKey.cleanup file oldkey newkey
genkey = do
content <- calcRepo $ gitAnnexLocation oldkey
let source = KeySource
{ keyFilename = file
, contentLocation = content
, inodeCache = Nothing
}
liftM fst <$> genKey source (Just newbackend)