From ca9d473a3e300bcddc73c00fdf2f4bf6ca43c4a2 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Thu, 20 Aug 2020 11:46:08 -0400 Subject: [PATCH] btrfs: use BTRFS_NESTED_NEW_ROOT for double splits I've made this change separate since it requires both of the newly added NESTED flags and I didn't want to slip it into one of those changes. If we do a double split of a node we can end up doing a BTRFS_NESTED_SPLIT on level 0, which throws lockdep off because it appears as a double lock. Since we're maxed out on subclasses, use BTRFS_NESTED_NEW_ROOT if we had to do a double split. This is OK because we won't have to do a double split if we had to insert a new root, and the new root would be at a higher level anyway. Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/ctree.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index d61ea238ad8a1..7dbfa365eb18b 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -4324,8 +4324,18 @@ again: else btrfs_item_key(l, &disk_key, mid); + /* + * We have to about BTRFS_NESTING_NEW_ROOT here if we've done a double + * split, because we're only allowed to have MAX_LOCKDEP_SUBCLASSES + * subclasses, which is 8 at the time of this patch, and we've maxed it + * out. In the future we could add a + * BTRFS_NESTING_SPLIT_THE_SPLITTENING if we need to, but for now just + * use BTRFS_NESTING_NEW_ROOT. + */ right = alloc_tree_block_no_bg_flush(trans, root, 0, &disk_key, 0, - l->start, 0, BTRFS_NESTING_SPLIT); + l->start, 0, num_doubles ? + BTRFS_NESTING_NEW_ROOT : + BTRFS_NESTING_SPLIT); if (IS_ERR(right)) return PTR_ERR(right); -- 2.30.2