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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/btrfsvol"
)
type RebuiltForrestCallbacks interface {
AddedItem(ctx context.Context, tree btrfsprim.ObjID, key btrfsprim.Key)
AddedRoot(ctx context.Context, tree btrfsprim.ObjID, root btrfsvol.LogicalAddr)
LookupRoot(ctx context.Context, tree btrfsprim.ObjID) (offset btrfsprim.Generation, item btrfsitem.Root, ok bool)
LookupUUID(ctx context.Context, uuid btrfsprim.UUID) (id btrfsprim.ObjID, ok bool)
}
type noopRebuiltForrestCallbacks struct {
forrest *RebuiltForrest
}
func (noopRebuiltForrestCallbacks) AddedItem(context.Context, btrfsprim.ObjID, btrfsprim.Key) {}
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, ok bool) {
rootTree := cb.forrest.RebuiltTree(ctx, btrfsprim.ROOT_TREE_OBJECTID)
if rootTree == nil {
return 0, btrfsitem.Root{}, false
}
tgt := btrfsprim.Key{
ObjectID: tree,
ItemType: btrfsprim.ROOT_ITEM_KEY,
}
itemKey, itemPtr, ok := rootTree.RebuiltAcquireItems(ctx).Search(func(key btrfsprim.Key, _ ItemPtr) int {
key.Offset = 0
return tgt.Compare(key)
})
rootTree.RebuiltReleaseItems()
if !ok {
return 0, btrfsitem.Root{}, false
}
itemBody := cb.forrest.readItem(ctx, itemPtr)
defer itemBody.Free()
switch itemBody := itemBody.(type) {
case *btrfsitem.Root:
return btrfsprim.Generation(itemKey.Offset), *itemBody, true
case *btrfsitem.Error:
return 0, btrfsitem.Root{}, false
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, ok bool) {
uuidTree := cb.forrest.RebuiltTree(ctx, btrfsprim.UUID_TREE_OBJECTID)
if uuidTree == nil {
return 0, false
}
tgt := btrfsitem.UUIDToKey(uuid)
itemPtr, ok := uuidTree.RebuiltAcquireItems(ctx).Load(tgt)
uuidTree.RebuiltReleaseItems()
if !ok {
return 0, false
}
itemBody := cb.forrest.readItem(ctx, itemPtr)
defer itemBody.Free()
switch itemBody := itemBody.(type) {
case *btrfsitem.UUIDMap:
return itemBody.ObjID, true
case *btrfsitem.Error:
return 0, false
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))
}
}
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