From 3cd47f997873ff9d50b35c0f4440763364766d93 Mon Sep 17 00:00:00 2001
From: Joey Hess <joeyh@joeyh.name>
Date: Mon, 2 Oct 2017 13:55:26 -0400
Subject: [PATCH] info: Improve cleanup of stale transfer info files.

In my git-annex repos, I found some stale transfer info files
without lock files.

Pass a mode to tryLockExclusive, so it will create the lock file if
not present, and so not fail to clean up such transfer info files.

Normally, transfer info files are accompanied by a lock file.
But, when alwaysRunTransfer is used, the locking can fail
and it will still write the transfer info file. Perhaps there are other
cases too? Note that mkProgressUpdater's meter
writes to the transfer info file too, and it might be possible for
that meter to fire after runTransfer has cleaned up.

This commit was sponsored by andrea rota.
---
 CHANGELOG                                     |  1 +
 Logs/Transfer.hs                              | 13 +++++++------
 ..._cf2ae4db1fdb421b59d85edd9e58b868._comment | 19 +++++++++++++++++++
 3 files changed, 27 insertions(+), 6 deletions(-)
 create mode 100644 doc/forum/Can_I_purge_.git__47__annex__47__transfer_directory___63__/comment_3_cf2ae4db1fdb421b59d85edd9e58b868._comment

diff --git a/CHANGELOG b/CHANGELOG
index 91a4ac53a4..5895a7f8a5 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -17,6 +17,7 @@ git-annex (6.20170926) UNRELEASED; urgency=medium
   * Fix process and file descriptor leak that was exposed when
     git-annex was built with ghc 8.2.1. Broke git-annex test on OSX
     due to running out of FDs, and may have also leaked in other situations.
+  * info: Improve cleanup of stale transfer info files.
 
  -- Joey Hess <id@joeyh.name>  Thu, 28 Sep 2017 12:01:39 -0400
 
diff --git a/Logs/Transfer.hs b/Logs/Transfer.hs
index aef233b771..0aded154d7 100644
--- a/Logs/Transfer.hs
+++ b/Logs/Transfer.hs
@@ -93,22 +93,23 @@ startTransferInfo afile = TransferInfo
 checkTransfer :: Transfer -> Annex (Maybe TransferInfo)
 checkTransfer t = do
 	tfile <- fromRepo $ transferFile t
+	let lck = transferLockFile tfile
 	let cleanstale = do
 		void $ tryIO $ removeFile tfile
-		void $ tryIO $ removeFile $ transferLockFile tfile
+		void $ tryIO $ removeFile lck
 #ifndef mingw32_HOST_OS
-	let lck = transferLockFile tfile
 	v <- getLockStatus lck
 	case v of
 		StatusLockedBy pid -> liftIO $ catchDefaultIO Nothing $
 			readTransferInfoFile (Just pid) tfile
-		StatusNoLockFile -> return Nothing
-		StatusUnLocked -> do
+		_ -> do
 			-- Take a non-blocking lock while deleting
 			-- the stale lock file. Ignore failure
 			-- due to permissions problems, races, etc.
 			void $ tryIO $ do
-				r <- tryLockExclusive Nothing lck
+				mode <- annexFileMode
+				let lck = transferLockFile tfile
+				r <- tryLockExclusive (Just mode) lck
 				case r of
 					Just lockhandle -> liftIO $ do
 						cleanstale
@@ -116,7 +117,7 @@ checkTransfer t = do
 					_ -> noop
 			return Nothing
 #else
-	v <- liftIO $ lockShared $ transferLockFile tfile
+	v <- liftIO $ lockShared lck
 	liftIO $ case v of
 		Nothing -> catchDefaultIO Nothing $
 			readTransferInfoFile Nothing tfile
diff --git a/doc/forum/Can_I_purge_.git__47__annex__47__transfer_directory___63__/comment_3_cf2ae4db1fdb421b59d85edd9e58b868._comment b/doc/forum/Can_I_purge_.git__47__annex__47__transfer_directory___63__/comment_3_cf2ae4db1fdb421b59d85edd9e58b868._comment
new file mode 100644
index 0000000000..3c2f8016aa
--- /dev/null
+++ b/doc/forum/Can_I_purge_.git__47__annex__47__transfer_directory___63__/comment_3_cf2ae4db1fdb421b59d85edd9e58b868._comment
@@ -0,0 +1,19 @@
+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 3"""
+ date="2017-10-02T16:55:59Z"
+ content="""
+It's fine to delete .git/annex/transfer/ at any time.
+
+Those files are used to make `git annex info` (and the webapp) be able to
+show what transfers are in progress. Normally they're cleaned up when a
+transfer finishes; if you interrupt git-annex they will be left behind.
+
+Running `git annex info` is also supposed to clean up the stale transfer
+info files, but it was broken -- now fixed.
+
+The only time you get files in .git/annex/bad/ is when fsck finds a file
+got corrupted somehow and moves its content there. It's fine to delete
+those unless you were planning to recover or examine the corrupted file in
+some way.
+"""]]