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// Copyright (C) 2022 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package btrfsutil
import (
"context"
"fmt"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsitem"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsprim"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfstree"
)
type WalkError struct {
TreeName string
Err *btrfstree.TreeError
}
func (e *WalkError) Unwrap() error { return e.Err }
func (e *WalkError) Error() string {
return fmt.Sprintf("%v: %v", e.TreeName, e.Err)
}
type WalkAllTreesHandler struct {
Err func(*WalkError)
// Callbacks for entire trees
PreTree func(name string, id btrfsprim.ObjID)
PostTree func(name string, id btrfsprim.ObjID)
// Callbacks for nodes or smaller
btrfstree.TreeWalkHandler
}
// WalkAllTrees walks all trees in a *btrfs.FS. Rather than returning
// an error, it calls errCb each time an error is encountered. The
// error will always be of type WalkError.
func WalkAllTrees(ctx context.Context, fs btrfstree.TreeOperator, cbs WalkAllTreesHandler) {
var treeName string
trees := []struct {
Name string
ID btrfsprim.ObjID
}{
{
Name: "root tree",
ID: btrfsprim.ROOT_TREE_OBJECTID,
},
{
Name: "chunk tree",
ID: btrfsprim.CHUNK_TREE_OBJECTID,
},
{
Name: "log tree",
ID: btrfsprim.TREE_LOG_OBJECTID,
},
{
Name: "block group tree",
ID: btrfsprim.BLOCK_GROUP_TREE_OBJECTID,
},
}
origItem := cbs.Item
cbs.Item = func(path btrfstree.TreePath, item btrfstree.Item) error {
if item.Key.ItemType == btrfsitem.ROOT_ITEM_KEY {
trees = append(trees, struct {
Name string
ID btrfsprim.ObjID
}{
Name: fmt.Sprintf("tree %v (via %v %v)",
item.Key.ObjectID.Format(0), treeName, path),
ID: item.Key.ObjectID,
})
}
if origItem != nil {
return origItem(path, item)
}
return nil
}
for i := 0; i < len(trees); i++ {
tree := trees[i]
treeName = tree.Name
if cbs.PreTree != nil {
cbs.PreTree(treeName, tree.ID)
}
fs.TreeWalk(
ctx,
tree.ID,
func(err *btrfstree.TreeError) { cbs.Err(&WalkError{TreeName: treeName, Err: err}) },
cbs.TreeWalkHandler,
)
if cbs.PostTree != nil {
cbs.PostTree(treeName, tree.ID)
}
}
}
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