kernel: Remove obsolete btrfs patch

pkgs/os-specific/linux/kernel/btrfs-fix-deadlock.patch

@@ -1,43 +0,0 @@
-From 9c4f61f01d269815bb7c37be3ede59c5587747c6 Mon Sep 17 00:00:00 2001
-From: David Sterba <dsterba@suse.cz>
-Date: Fri, 2 Jan 2015 19:12:57 +0100
-Subject: btrfs: simplify insert_orphan_item
-
-We can search and add the orphan item in one go,
-btrfs_insert_orphan_item will find out if the item already exists.
-
-Signed-off-by: David Sterba <dsterba@suse.cz>
-
-diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
-index 5be45c1..25a1c36 100644
---- a/fs/btrfs/tree-log.c
-+++ b/fs/btrfs/tree-log.c
-@@ -1254,21 +1254,13 @@ out:
- }
- 
- static int insert_orphan_item(struct btrfs_trans_handle *trans,
--			      struct btrfs_root *root, u64 offset)
-+			      struct btrfs_root *root, u64 ino)
- {
- 	int ret;
--	struct btrfs_path *path;
--
--	path = btrfs_alloc_path();
--	if (!path)
--		return -ENOMEM;
- 
--	ret = btrfs_find_item(root, path, BTRFS_ORPHAN_OBJECTID,
--			offset, BTRFS_ORPHAN_ITEM_KEY, NULL);
--	if (ret > 0)
--		ret = btrfs_insert_orphan_item(trans, root, offset);
--
--	btrfs_free_path(path);
-+	ret = btrfs_insert_orphan_item(trans, root, ino);
-+	if (ret == -EEXIST)
-+		ret = 0;
- 
- 	return ret;
- }
--- 
-cgit v0.10.2
-

pkgs/os-specific/linux/kernel/linux-3.18.nix

@@ -9,13 +9,6 @@ import ./generic.nix (args // rec {
     sha256 = "043bqjvbamzi201csgnw7hsf8810qm0dn7x9p0kc7s9p9jnyq79n";
   };
 
-  # FIXME: remove with the next point release.
-  kernelPatches = args.kernelPatches ++
-    [ { name = "btrfs-fix-deadlock";
-        patch = ./btrfs-fix-deadlock.patch;
-      }
-    ];
-
   features.iwlwifi = true;
   features.efiBootStub = true;
   features.needsCifsUtils = true;