btrfs: use a structure to pass arguments to backref walking functions

The public backref walking functions have quite a lot of arguments that
are passed down the call stack to find_parent_nodes(), the core function
of the backref walking code.

The next patches in series will need to add even arguments to these
functions that should be passed not only to find_parent_nodes(), but also
to other functions used by the later (directly or even lower in the call
stack).

So create a structure to hold all these arguments and state used by the
main backref walking function, find_parent_nodes(), and use it as the
argument for the public backref walking functions iterate_extent_inodes(),
btrfs_find_all_leafs() and btrfs_find_all_roots().

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 11 insertions, 8 deletions

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 45690f7b5900..2ecca24e1001 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -3408,24 +3408,27 @@ int add_data_references(struct reloc_control *rc,
 			struct btrfs_path *path,
 			struct rb_root *blocks)
 {
-	struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
-	struct ulist *leaves = NULL;
+	struct btrfs_backref_walk_ctx ctx = { 0 };
 	struct ulist_iterator leaf_uiter;
 	struct ulist_node *ref_node = NULL;
-	const u32 blocksize = fs_info->nodesize;
+	const u32 blocksize = rc->extent_root->fs_info->nodesize;
 	int ret = 0;
 
 	btrfs_release_path(path);
-	ret = btrfs_find_all_leafs(NULL, fs_info, extent_key->objectid,
-				   0, &leaves, BTRFS_IGNORE_EXTENT_OFFSET);
+
+	ctx.bytenr = extent_key->objectid;
+	ctx.ignore_extent_item_pos = true;
+	ctx.fs_info = rc->extent_root->fs_info;
+
+	ret = btrfs_find_all_leafs(&ctx);
 	if (ret < 0)
 		return ret;
 
 	ULIST_ITER_INIT(&leaf_uiter);
-	while ((ref_node = ulist_next(leaves, &leaf_uiter))) {
+	while ((ref_node = ulist_next(ctx.refs, &leaf_uiter))) {
 		struct extent_buffer *eb;
 
-		eb = read_tree_block(fs_info, ref_node->val, 0, 0, 0, NULL);
+		eb = read_tree_block(ctx.fs_info, ref_node->val, 0, 0, 0, NULL);
 		if (IS_ERR(eb)) {
 			ret = PTR_ERR(eb);
 			break;
@@ -3441,7 +3444,7 @@ int add_data_references(struct reloc_control *rc,
 	}
 	if (ret < 0)
 		free_block_list(blocks);
-	ulist_free(leaves);
+	ulist_free(ctx.refs);
 	return ret;
 }