@@ -4250,8 +4250,18 @@ static noinline int split_leaf(struct btrfs_trans_handle *trans,
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);
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 <josef@toxicpanda.com> --- fs/btrfs/ctree.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)