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// Copyright (C) 2022 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package btrfs
import (
"context"
"fmt"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsitem"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
"git.lukeshu.com/btrfs-progs-ng/lib/containers"
"git.lukeshu.com/btrfs-progs-ng/lib/diskio"
)
var _ Trees = (*FS)(nil)
func (fs *FS) populateTreeUUIDs(ctx context.Context) {
if fs.cacheObjID2UUID == nil || fs.cacheUUID2ObjID == nil || fs.cacheTreeParent == nil {
fs.cacheObjID2UUID = make(map[ObjID]UUID)
fs.cacheUUID2ObjID = make(map[UUID]ObjID)
fs.cacheTreeParent = make(map[ObjID]UUID)
fs.TreeWalk(ctx, ROOT_TREE_OBJECTID,
func(err *TreeError) {
// do nothing
},
TreeWalkHandler{
Item: func(_ TreePath, item Item) error {
itemBody, ok := item.Body.(btrfsitem.Root)
if !ok {
return nil
}
fs.cacheObjID2UUID[item.Key.ObjectID] = itemBody.UUID
fs.cacheTreeParent[item.Key.ObjectID] = itemBody.ParentUUID
fs.cacheUUID2ObjID[itemBody.UUID] = item.Key.ObjectID
return nil
},
},
)
}
}
func (fs *FS) ReadNode(path TreePath) (*diskio.Ref[btrfsvol.LogicalAddr, Node], error) {
sb, err := fs.Superblock()
if err != nil {
return nil, fmt.Errorf("btrfs.FS.ReadNode: %w", err)
}
potentialOwners := []ObjID{
path.Node(-1).FromTree,
}
if potentialOwners[0] >= FIRST_FREE_OBJECTID {
ctx := context.TODO()
fs.populateTreeUUIDs(ctx)
for potentialOwners[len(potentialOwners)-1] >= FIRST_FREE_OBJECTID {
objID := potentialOwners[len(potentialOwners)-1]
parentUUID := fs.cacheTreeParent[objID]
if parentUUID == (UUID{}) {
break
}
parentObjID, ok := fs.cacheUUID2ObjID[parentUUID]
if !ok {
break
}
potentialOwners = append(potentialOwners, parentObjID)
}
}
return ReadNode[btrfsvol.LogicalAddr](fs, *sb, path.Node(-1).ToNodeAddr, NodeExpectations{
LAddr: containers.Optional[btrfsvol.LogicalAddr]{OK: true, Val: path.Node(-1).ToNodeAddr},
Level: containers.Optional[uint8]{OK: true, Val: path.Node(-1).ToNodeLevel},
MaxGeneration: containers.Optional[Generation]{OK: true, Val: path.Node(-1).FromGeneration},
Owner: potentialOwners,
})
}
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