From 3456bf086603d11ae77b15e381d6523105f75f15 Mon Sep 17 00:00:00 2001 From: Eric Sandeen Date: Mon, 22 Apr 2013 00:01:26 -0500 Subject: [PATCH] btrfs-progs: set generation_v2 any time we write a new root 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 --- root-tree.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/root-tree.c b/root-tree.c index c10d0684..ef2190fc 100644 --- a/root-tree.c +++ b/root-tree.c @@ -92,6 +92,11 @@ 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; }