From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:16232 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751646Ab3DVFB3 (ORCPT ); Mon, 22 Apr 2013 01:01:29 -0400 Message-ID: <5174C426.3030204@redhat.com> Date: Mon, 22 Apr 2013 00:01:26 -0500 From: Eric Sandeen MIME-Version: 1.0 To: linux-btrfs CC: Anand Jain , Alexander Block Subject: [PATCH 1/2] btrfs-progs: set generation_v2 any time we write a new root Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-btrfs-owner@vger.kernel.org List-ID: With this integration branch commit in place: 2bd1169 btrfs-progs: root_item generation_v2 is out of sync after btrfsck I started seeing generation mismatch messages from the kernel at mount time, after a fresh mkfs(!): btrfs: mismatching generation and generation_v2 found in root item... This is because the code which emits the warning does not do so if there is a mismatch but generation_v2 is 0; the above commit began setting generation_v2 to something non-zero, so the warning was emitted. The reason there is a mismatch at all is because mkfs.btrfs calls create_data_reloc_tree(), which copies a root, and then calls btrfs_set_root_generation(), bumping the original copied generation. But nothing updated generation_v2 to match on the way to disk. Fix this by updating generation_v2 in btrfs_insert_root(), as is done in the kernel. This is safe because it's a new root created by userspace, so the btrfs_root_item is guaranteed to be big enough to contain generation_v2. Signed-off-by: Eric Sandeen --- Another example of why we need to get userspace in sync with kernelspace... diff --git a/root-tree.c b/root-tree.c index 4454147..1823918 100644 --- a/root-tree.c +++ b/root-tree.c @@ -105,6 +105,11 @@ int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *item) { int ret; + + /* + * Make sure generation v1 and v2 match. See update_root for details. + */ + btrfs_set_root_generation_v2(item, btrfs_root_generation(item)); ret = btrfs_insert_item(trans, root, key, item, sizeof(*item)); return ret; }