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// Copyright (C) 2022-2023 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"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
)
type RebuiltForrestCallbacks interface {
AddedRoot(ctx context.Context, tree btrfsprim.ObjID, root btrfsvol.LogicalAddr)
LookupRoot(ctx context.Context, tree btrfsprim.ObjID) (offset btrfsprim.Generation, item btrfsitem.Root, err error)
LookupUUID(ctx context.Context, uuid btrfsprim.UUID) (id btrfsprim.ObjID, err error)
}
type RebuiltForrestExtendedCallbacks interface {
RebuiltForrestCallbacks
AddedItem(ctx context.Context, tree btrfsprim.ObjID, key btrfsprim.Key)
}
type noopRebuiltForrestCallbacks struct {
forrest btrfstree.Forrest
}
func (noopRebuiltForrestCallbacks) AddedRoot(context.Context, btrfsprim.ObjID, btrfsvol.LogicalAddr) {
}
func (cb noopRebuiltForrestCallbacks) LookupRoot(ctx context.Context, tree btrfsprim.ObjID) (offset btrfsprim.Generation, _item btrfsitem.Root, err error) {
rootTree, err := cb.forrest.ForrestLookup(ctx, btrfsprim.ROOT_TREE_OBJECTID)
if err != nil {
return 0, btrfsitem.Root{}, err
}
item, err := rootTree.TreeSearch(ctx, btrfstree.SearchRootItem(tree))
if err != nil {
return 0, btrfsitem.Root{}, err
}
defer item.Body.Free()
switch itemBody := item.Body.(type) {
case *btrfsitem.Root:
return btrfsprim.Generation(item.Key.Offset), *itemBody, nil
case *btrfsitem.Error:
return 0, btrfsitem.Root{}, itemBody.Err
default:
// This is a panic because the item decoder should not emit ROOT_ITEM items as anything but
// btrfsitem.Root or btrfsitem.Error without this code also being updated.
panic(fmt.Errorf("should not happen: ROOT_ITEM item has unexpected type: %T", itemBody))
}
}
func (cb noopRebuiltForrestCallbacks) LookupUUID(ctx context.Context, uuid btrfsprim.UUID) (id btrfsprim.ObjID, err error) {
uuidTree, err := cb.forrest.ForrestLookup(ctx, btrfsprim.UUID_TREE_OBJECTID)
if err != nil {
if id, ok := cb.slowLookupUUID(ctx, uuid); ok {
return id, nil
}
return 0, err
}
tgt := btrfsitem.UUIDToKey(uuid)
item, err := uuidTree.TreeLookup(ctx, tgt)
if err != nil {
if id, ok := cb.slowLookupUUID(ctx, uuid); ok {
return id, nil
}
return 0, err
}
defer item.Body.Free()
switch itemBody := item.Body.(type) {
case *btrfsitem.UUIDMap:
return itemBody.ObjID, nil
case *btrfsitem.Error:
if id, ok := cb.slowLookupUUID(ctx, uuid); ok {
return id, nil
}
return 0, err
default:
// This is a panic because the item decoder should not emit UUID_SUBVOL items as anything but
// btrfsitem.UUIDMap or btrfsitem.Error without this code also being updated.
panic(fmt.Errorf("should not happen: UUID_SUBVOL item has unexpected type: %T", itemBody))
}
}
func (cb noopRebuiltForrestCallbacks) slowLookupUUID(ctx context.Context, uuid btrfsprim.UUID) (id btrfsprim.ObjID, ok bool) {
rootTree, err := cb.forrest.ForrestLookup(ctx, btrfsprim.ROOT_TREE_OBJECTID)
if err != nil {
return 0, false
}
var ret btrfsprim.ObjID
_ = rootTree.TreeRange(ctx, func(item btrfstree.Item) bool {
if item.Key.ItemType != btrfsprim.ROOT_ITEM_KEY {
return true
}
switch itemBody := item.Body.(type) {
case *btrfsitem.Root:
if itemBody.UUID == uuid {
ret = item.Key.ObjectID
return false
}
case *btrfsitem.Error:
// do nothing
default:
// This is a panic because the item decoder should not emit ROOT_ITEM items as anything but
// btrfsitem.Root or btrfsitem.Error without this code also being updated.
panic(fmt.Errorf("should not happen: ROOT_ITEM item has unexpected type: %T", itemBody))
}
return true
})
if ret == 0 {
return 0, false
}
return ret, true
}
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