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// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package btrees
import (
"context"
"github.com/datawire/dlib/dlog"
"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"
pkggraph "git.lukeshu.com/btrfs-progs-ng/lib/btrfsprogs/btrfsinspect/rebuildnodes/graph"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfsprogs/btrfsinspect/rebuildnodes/keyio"
"git.lukeshu.com/btrfs-progs-ng/lib/containers"
"git.lukeshu.com/btrfs-progs-ng/lib/slices"
"git.lukeshu.com/btrfs-progs-ng/lib/textui"
)
// RebuiltForrest is an abstraction for rebuilding and accessing
// potentially broken btrees.
//
// It is conceptually a btrfstree.TreeOperator, and adds similar
// broken-tree handling to btrfsutil.BrokenForrest. However, the API
// is different thant btrfstree.TreeOperator, and is much more
// efficient than btrfsutil.BrokenForrest.
//
// The efficiency improvements are possible because of the API
// differences, which are necessary for how it is used in
// rebuildnodes:
//
// - it consumes an already-read graph.Graph instead of reading the
// graph itself
//
// - it does not use `btrfstree.TreePath`
//
// - it does not keep track of errors encountered in a tree
//
// Additionally, it provides some functionality that
// btrfsutil.BrokenForrest does not:
//
// - it provides a .LeafToRoots() method to advise on what
// additional roots should be added
//
// - it provides a .COWDistance() method to compare how related two
// trees are
//
// A zero RebuiltForrest is invalid; it must be initialized with
// NewRebuiltForrest().
type RebuiltForrest struct {
// static
sb btrfstree.Superblock
graph pkggraph.Graph
keyIO *keyio.Handle
// static callbacks
cbAddedItem func(ctx context.Context, tree btrfsprim.ObjID, key btrfsprim.Key)
cbLookupRoot func(ctx context.Context, tree btrfsprim.ObjID) (offset btrfsprim.Generation, item btrfsitem.Root, ok bool)
cbLookupUUID func(ctx context.Context, uuid btrfsprim.UUID) (id btrfsprim.ObjID, ok bool)
// mutable
trees containers.SyncMap[btrfsprim.ObjID, *RebuiltTree]
allItems *containers.LRUCache[btrfsprim.ObjID, *itemIndex]
incItems *containers.LRUCache[btrfsprim.ObjID, *itemIndex]
}
// NewRebuiltForrest returns a new RebuiltForrest instance. All of
// the callbacks must be non-nil.
func NewRebuiltForrest(
sb btrfstree.Superblock, graph pkggraph.Graph, keyIO *keyio.Handle,
cbAddedItem func(ctx context.Context, tree btrfsprim.ObjID, key btrfsprim.Key),
cbLookupRoot func(ctx context.Context, tree btrfsprim.ObjID) (offset btrfsprim.Generation, item btrfsitem.Root, ok bool),
cbLookupUUID func(ctx context.Context, uuid btrfsprim.UUID) (id btrfsprim.ObjID, ok bool),
) *RebuiltForrest {
return &RebuiltForrest{
sb: sb,
graph: graph,
keyIO: keyIO,
cbAddedItem: cbAddedItem,
cbLookupRoot: cbLookupRoot,
cbLookupUUID: cbLookupUUID,
allItems: containers.NewLRUCache[btrfsprim.ObjID, *itemIndex](textui.Tunable(8)),
incItems: containers.NewLRUCache[btrfsprim.ObjID, *itemIndex](textui.Tunable(8)),
}
}
// Tree returns a given tree, initializing it if nescessary. If it is
// unable to initialize the tree, then nil is returned, and nothing is
// done to the forrest.
//
// The tree is initialized with the normal root node of the tree.
func (ts *RebuiltForrest) Tree(ctx context.Context, treeID btrfsprim.ObjID) *RebuiltTree {
if !ts.addTree(ctx, treeID, nil) {
return nil
}
tree, _ := ts.trees.Load(treeID)
return tree
}
func (ts *RebuiltForrest) addTree(ctx context.Context, treeID btrfsprim.ObjID, stack []btrfsprim.ObjID) (ok bool) {
if _, ok := ts.trees.Load(treeID); ok {
return true
}
if slices.Contains(treeID, stack) {
return false
}
stack = append(stack, treeID)
ctx = dlog.WithField(ctx, "btrfsinspect.rebuild-nodes.rebuild.add-tree", stack)
dlog.Info(ctx, "adding tree...")
tree := &RebuiltTree{
ID: treeID,
Roots: make(containers.Set[btrfsvol.LogicalAddr]),
Leafs: make(containers.Set[btrfsvol.LogicalAddr]),
forrest: ts,
}
var root btrfsvol.LogicalAddr
switch treeID {
case btrfsprim.ROOT_TREE_OBJECTID:
root = ts.sb.RootTree
case btrfsprim.CHUNK_TREE_OBJECTID:
root = ts.sb.ChunkTree
case btrfsprim.TREE_LOG_OBJECTID:
root = ts.sb.LogTree
case btrfsprim.BLOCK_GROUP_TREE_OBJECTID:
root = ts.sb.BlockGroupRoot
default:
if !ts.addTree(ctx, btrfsprim.ROOT_TREE_OBJECTID, stack) {
return false
}
rootOff, rootItem, ok := ts.cbLookupRoot(ctx, treeID)
if !ok {
return false
}
root = rootItem.ByteNr
tree.UUID = rootItem.UUID
if rootItem.ParentUUID != (btrfsprim.UUID{}) {
tree.ParentGen = rootOff
if !ts.addTree(ctx, btrfsprim.UUID_TREE_OBJECTID, stack) {
return false
}
parentID, ok := ts.cbLookupUUID(ctx, rootItem.ParentUUID)
if !ok {
return false
}
if !ts.addTree(ctx, parentID, append(stack, treeID)) {
return false
}
tree.Parent, _ = ts.trees.Load(parentID)
}
}
tree.indexLeafs(ctx)
ts.trees.Store(treeID, tree)
if root != 0 {
tree.AddRoot(ctx, root)
}
return true
}
// ListRoots returns a listing of all initialized trees and their root
// nodes.
//
// Do not mutate the set of roots for a tree; it is a pointer to the
// RebuiltForrest's internal set!
func (ts *RebuiltForrest) ListRoots() map[btrfsprim.ObjID]containers.Set[btrfsvol.LogicalAddr] {
ret := make(map[btrfsprim.ObjID]containers.Set[btrfsvol.LogicalAddr])
ts.trees.Range(func(treeID btrfsprim.ObjID, tree *RebuiltTree) bool {
ret[treeID] = tree.Roots
return true
})
return ret
}
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