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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"
"reflect"
"time"
"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"
"git.lukeshu.com/btrfs-progs-ng/lib/containers"
"git.lukeshu.com/btrfs-progs-ng/lib/maps"
"git.lukeshu.com/btrfs-progs-ng/lib/slices"
"git.lukeshu.com/btrfs-progs-ng/lib/textui"
)
type GraphNode struct {
Level uint8
Generation btrfsprim.Generation
Owner btrfsprim.ObjID
Items []btrfsprim.Key
}
func (n GraphNode) MinItem() btrfsprim.Key {
if len(n.Items) == 0 {
return btrfsprim.Key{}
}
return n.Items[0]
}
func (n GraphNode) MaxItem() btrfsprim.Key {
if len(n.Items) == 0 {
return btrfsprim.Key{}
}
return n.Items[len(n.Items)-1]
}
func (n GraphNode) String() string {
if reflect.ValueOf(n).IsZero() {
return "{}"
}
return fmt.Sprintf(`{lvl:%v, gen:%v, tree:%v, cnt:%v, min:(%v,%v,%v), max:(%v,%v,%v)}`,
n.Level, n.Generation, n.Owner, len(n.Items),
n.MinItem().ObjectID, n.MinItem().ItemType, n.MinItem().Offset,
n.MaxItem().ObjectID, n.MaxItem().ItemType, n.MaxItem().Offset)
}
type GraphEdge struct {
// It is invalid for both 'FromRoot' and 'FromNode' to be
// non-zero. If both are zero, then the GraphEdge is from the
// superblock.
FromRoot btrfsvol.LogicalAddr
FromNode btrfsvol.LogicalAddr
FromItem int // only valid if one of FromRoot or FromNode is non-zero
FromTree btrfsprim.ObjID
ToNode btrfsvol.LogicalAddr
ToLevel uint8
ToKey btrfsprim.Key
ToGeneration btrfsprim.Generation
}
func (kp GraphEdge) String() string {
var from string
switch {
case kp.FromRoot != 0:
from = fmt.Sprintf("root@%v[%d]:%v",
kp.FromRoot, kp.FromItem, kp.FromTree)
case kp.FromNode != 0:
from = fmt.Sprintf("{node:%v, tree:%v}[%d]",
kp.FromNode, kp.FromTree, kp.FromItem)
default:
from = fmt.Sprintf("superblock:%v", kp.FromTree)
}
return fmt.Sprintf(`%s -> {n:%v,l:%v,g:%v,k:(%v,%v,%v)}`,
from,
kp.ToNode, kp.ToLevel, kp.ToGeneration,
kp.ToKey.ObjectID,
kp.ToKey.ItemType,
kp.ToKey.Offset)
}
type Graph struct {
Nodes map[btrfsvol.LogicalAddr]GraphNode
BadNodes map[btrfsvol.LogicalAddr]error
EdgesFrom map[btrfsvol.LogicalAddr][]*GraphEdge
EdgesTo map[btrfsvol.LogicalAddr][]*GraphEdge
}
func (g Graph) insertEdge(ptr *GraphEdge) {
if ptr.ToNode == 0 {
panic("kp.ToNode should not be zero")
}
if ptr.FromRoot != 0 && ptr.FromNode != 0 {
panic("kp.FromRoot and kp.FromNode should not both be set")
}
if (ptr.FromRoot == 0 && ptr.FromNode == 0) && ptr.FromItem != 0 {
panic("kp.FromItem should only be set if either kp.FromRoot or kp.FromItem is set")
}
g.EdgesFrom[ptr.FromNode] = append(g.EdgesFrom[ptr.FromNode], ptr)
g.EdgesTo[ptr.ToNode] = append(g.EdgesTo[ptr.ToNode], ptr)
}
func (g Graph) insertTreeRoot(ctx context.Context, sb btrfstree.Superblock, treeID btrfsprim.ObjID) {
treeInfo, err := btrfstree.LookupTreeRoot(ctx, nil, sb, treeID)
if err != nil {
// This shouldn't ever happen for treeIDs that are
// mentioned directly in the superblock; which are the
// only trees for which we should call
// .insertTreeRoot().
panic(fmt.Errorf("LookupTreeRoot(%v): %w", treeID, err))
}
if treeInfo.RootNode == 0 {
return
}
g.insertEdge(&GraphEdge{
FromTree: treeID,
ToNode: treeInfo.RootNode,
ToLevel: treeInfo.Level,
ToGeneration: treeInfo.Generation,
})
}
func NewGraph(ctx context.Context, sb btrfstree.Superblock) Graph {
g := Graph{
Nodes: make(map[btrfsvol.LogicalAddr]GraphNode),
BadNodes: make(map[btrfsvol.LogicalAddr]error),
EdgesFrom: make(map[btrfsvol.LogicalAddr][]*GraphEdge),
EdgesTo: make(map[btrfsvol.LogicalAddr][]*GraphEdge),
}
// These 4 trees are mentioned directly in the superblock, so
// they are always seen.
g.insertTreeRoot(ctx, sb, btrfsprim.ROOT_TREE_OBJECTID)
g.insertTreeRoot(ctx, sb, btrfsprim.CHUNK_TREE_OBJECTID)
g.insertTreeRoot(ctx, sb, btrfsprim.TREE_LOG_OBJECTID)
g.insertTreeRoot(ctx, sb, btrfsprim.BLOCK_GROUP_TREE_OBJECTID)
return g
}
func (g Graph) InsertNode(node *btrfstree.Node) {
nodeData := GraphNode{
Level: node.Head.Level,
Generation: node.Head.Generation,
Owner: node.Head.Owner,
}
if node.Head.Level == 0 {
cnt := 0
for _, item := range node.BodyLeaf {
if _, ok := item.Body.(*btrfsitem.Root); ok {
cnt++
}
}
kps := make([]GraphEdge, 0, cnt)
keys := make([]btrfsprim.Key, len(node.BodyLeaf))
nodeData.Items = keys
g.Nodes[node.Head.Addr] = nodeData
for i, item := range node.BodyLeaf {
keys[i] = item.Key
if itemBody, ok := item.Body.(*btrfsitem.Root); ok {
kps = append(kps, GraphEdge{
FromRoot: node.Head.Addr,
FromItem: i,
FromTree: item.Key.ObjectID,
ToNode: itemBody.ByteNr,
ToLevel: itemBody.Level,
ToGeneration: itemBody.Generation,
})
g.insertEdge(&kps[len(kps)-1])
}
}
} else {
g.Nodes[node.Head.Addr] = nodeData
kps := make([]GraphEdge, len(node.BodyInterior))
for i, kp := range node.BodyInterior {
kps[i] = GraphEdge{
FromNode: node.Head.Addr,
FromItem: i,
FromTree: node.Head.Owner,
ToNode: kp.BlockPtr,
ToLevel: node.Head.Level - 1,
ToKey: kp.Key,
ToGeneration: kp.Generation,
}
g.insertEdge(&kps[i])
}
}
}
func (g Graph) FinalCheck(ctx context.Context, fs btrfstree.NodeSource) error {
var stats textui.Portion[int]
dlog.Info(ctx, "Checking keypointers for dead-ends...")
progressWriter := textui.NewProgress[textui.Portion[int]](ctx, dlog.LogLevelInfo, textui.Tunable(1*time.Second))
stats.D = len(g.EdgesTo)
progressWriter.Set(stats)
for laddr := range g.EdgesTo {
if _, ok := g.Nodes[laddr]; !ok {
_, err := fs.ReadNode(ctx, laddr, btrfstree.NodeExpectations{
LAddr: containers.OptionalValue(laddr),
})
if err == nil {
progressWriter.Done()
return fmt.Errorf("node@%v exists but was not in node scan results", laddr)
}
g.BadNodes[laddr] = err
}
stats.N++
progressWriter.Set(stats)
}
progressWriter.Done()
dlog.Info(ctx, "... done checking keypointers")
dlog.Info(ctx, "Checking for btree loops...")
stats.D = len(g.Nodes)
stats.N = 0
progressWriter = textui.NewProgress[textui.Portion[int]](ctx, dlog.LogLevelInfo, textui.Tunable(1*time.Second))
progressWriter.Set(stats)
visited := make(containers.Set[btrfsvol.LogicalAddr], len(g.Nodes))
numLoops := 0
var checkNode func(node btrfsvol.LogicalAddr, stack []btrfsvol.LogicalAddr)
checkNode = func(node btrfsvol.LogicalAddr, stack []btrfsvol.LogicalAddr) {
defer func() {
stats.N = len(visited)
progressWriter.Set(stats)
}()
if visited.Has(node) {
return
}
if slices.Contains(node, stack) {
numLoops++
dlog.Error(ctx, "loop:")
for _, line := range g.renderLoop(append(stack, node)) {
dlog.Errorf(ctx, " %s", line)
}
return
}
stack = append(stack, node)
for _, kp := range g.EdgesTo[node] {
checkNode(kp.FromNode, stack)
}
visited.Insert(node)
}
for _, node := range maps.SortedKeys(g.Nodes) {
checkNode(node, nil)
}
progressWriter.Done()
if numLoops > 0 {
return fmt.Errorf("%d btree loops", numLoops)
}
dlog.Info(ctx, "... done checking for loops")
return nil
}
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