reorg to allow taking content lock

The lock will only persist during the perform stage, so the content must
be removed from the annex then, rather than in the cleanup stage.

(No lock is actually taken yet.)

Command/Move.hs

@@ -68,7 +68,7 @@ toStart dest move file = isAnnexed file $ \(key, _) -> do
 			showMoveAction move file
 			next $ toPerform dest move key
 toPerform :: Remote.Remote Annex -> Bool -> Key -> CommandPerform
-toPerform dest move key = do
+toPerform dest move key = moveLock move key $ do
 	-- Checking the remote is expensive, so not done in the start step.
 	-- In fast mode, location tracking is assumed to be correct,
 	-- and an explicit check is not done, when copying. When moving,
@@ -88,18 +88,20 @@ toPerform dest move key = do
 			showAction $ "to " ++ Remote.name dest
 			ok <- Remote.storeKey dest key
 			if ok
-				then next $ toCleanup dest move key
+				then finish
 				else do
 					when fastcheck $
 						warning "This could have failed because --fast is enabled."
 					stop
-		Right True -> next $ toCleanup dest move key
-toCleanup :: Remote.Remote Annex -> Bool -> Key -> CommandCleanup
-toCleanup dest move key = do
-	Remote.remoteHasKey dest key True
-	if move
-		then Command.Drop.cleanupLocal key
-		else return True
+		Right True -> finish
+	where
+		finish = do
+			Remote.remoteHasKey dest key True
+			if move
+				then do
+					whenM (inAnnex key) $ removeAnnex key
+					next $ Command.Drop.cleanupLocal key
+				else next $ return True
 
 {- Moves (or copies) the content of an annexed file from a remote
  - to the current repository.
@@ -117,16 +119,23 @@ fromStart src move file = isAnnexed file $ \(key, _) -> do
 			showMoveAction move file
 			next $ fromPerform src move key
 fromPerform :: Remote.Remote Annex -> Bool -> Key -> CommandPerform
-fromPerform src move key = do
+fromPerform src move key = moveLock move key $ do
 	ishere <- inAnnex key
 	if ishere
-		then next $ fromCleanup src move key
+		then handle move True
 		else do
 			showAction $ "from " ++ Remote.name src
 			ok <- getViaTmp key $ Remote.retrieveKeyFile src key
-			if ok
-				then next $ fromCleanup src move key
-				else stop -- fail
-fromCleanup :: Remote.Remote Annex -> Bool -> Key -> CommandCleanup
-fromCleanup src True key = Command.Drop.cleanupRemote key src
-fromCleanup _ False _ = return True
+			handle move ok
+	where
+		handle _ False = stop -- failed
+		handle False True = next $ return True -- copy complete
+		handle True True = do -- finish moving
+			ok <- Remote.removeKey src key
+			next $ Command.Drop.cleanupRemote key src ok
+
+{- Locks a key in order for it to be moved.
+ - No lock is needed when a key is being copied. -}
+moveLock :: Bool -> Key -> Annex a -> Annex a
+moveLock True key a = lockExclusive key a
+moveLock False _ a = a