btrfs: concentrate all tree block parentness check parameters into one structure

There are several different tree block parentness check parameters used
across several helpers:

- level
  Mandatory

- transid
  Under most cases it's mandatory, but there are several backref cases
  which skips this check.

- owner_root
- first_key
  Utilized by most top-down tree search routine. Otherwise can be
  skipped.

Those four members are not always mandatory checks, and some of them are
the same u64, which means if some arguments got swapped compiler will
not catch it.

Furthermore if we're going to further expand the parentness check, we
need to modify quite some helpers just to add one more parameter.

This patch will concentrate all these members into a structure called
btrfs_tree_parent_check, and pass that structure for the following
helpers:

- btrfs_read_extent_buffer()
- read_tree_block()

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 14 insertions, 4 deletions

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 24c013c61a94..e0522c6c0d67 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -2339,7 +2339,13 @@ int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
 	}
 
 	if (!extent_buffer_uptodate(root_eb)) {
-		ret = btrfs_read_extent_buffer(root_eb, root_gen, root_level, NULL);
+		struct btrfs_tree_parent_check check = {
+			.has_first_key = false,
+			.transid = root_gen,
+			.level = root_level
+		};
+
+		ret = btrfs_read_extent_buffer(root_eb, &check);
 		if (ret)
 			goto out;
 	}
@@ -4303,6 +4309,7 @@ int btrfs_qgroup_trace_subtree_after_cow(struct btrfs_trans_handle *trans,
 					 struct extent_buffer *subvol_eb)
 {
 	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct btrfs_tree_parent_check check = { 0 };
 	struct btrfs_qgroup_swapped_blocks *blocks = &root->swapped_blocks;
 	struct btrfs_qgroup_swapped_block *block;
 	struct extent_buffer *reloc_eb = NULL;
@@ -4351,10 +4358,13 @@ int btrfs_qgroup_trace_subtree_after_cow(struct btrfs_trans_handle *trans,
 	blocks->swapped = swapped;
 	spin_unlock(&blocks->lock);
 
+	check.level = block->level;
+	check.transid = block->reloc_generation;
+	check.has_first_key = true;
+	memcpy(&check.first_key, &block->first_key, sizeof(check.first_key));
+
 	/* Read out reloc subtree root */
-	reloc_eb = read_tree_block(fs_info, block->reloc_bytenr, 0,
-				   block->reloc_generation, block->level,
-				   &block->first_key);
+	reloc_eb = read_tree_block(fs_info, block->reloc_bytenr, &check);
 	if (IS_ERR(reloc_eb)) {
 		ret = PTR_ERR(reloc_eb);
 		reloc_eb = NULL;