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// Copyright (C) 2022 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package rebuildnodes
import (
"context"
"fmt"
"github.com/datawire/dlib/dlog"
"git.lukeshu.com/btrfs-progs-ng/lib/btrfs"
"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/btrfsprogs/btrfsinspect"
"git.lukeshu.com/btrfs-progs-ng/lib/containers"
"git.lukeshu.com/btrfs-progs-ng/lib/maps"
)
type nodeData struct {
Level uint8
Generation btrfsprim.Generation
Owner btrfsprim.ObjID
NumItems uint32
MinItem btrfsprim.Key
MaxItem btrfsprim.Key
}
type kpData struct {
FromTree btrfsprim.ObjID
FromNode btrfsvol.LogicalAddr
FromItem int
ToNode btrfsvol.LogicalAddr
ToLevel uint8
ToKey btrfsprim.Key
ToGeneration btrfsprim.Generation
}
func (kp kpData) String() string {
return fmt.Sprintf(`{t:%v,n:%v}[%d]->{n:%v,l:%v,g:%v,k:(%d,%v,%d)}`,
kp.FromTree, kp.FromNode, kp.FromItem,
kp.ToNode, kp.ToLevel, kp.ToGeneration,
kp.ToKey.ObjectID,
kp.ToKey.ItemType,
kp.ToKey.Offset)
}
type nodeGraph struct {
Nodes map[btrfsvol.LogicalAddr]nodeData
BadNodes map[btrfsvol.LogicalAddr]error
EdgesFrom map[btrfsvol.LogicalAddr][]*kpData
EdgesTo map[btrfsvol.LogicalAddr][]*kpData
}
func (g nodeGraph) insertEdge(kp kpData) {
ptr := &kp
if kp.ToNode == 0 {
panic("kp.ToNode should not be zero")
}
g.EdgesFrom[kp.FromNode] = append(g.EdgesFrom[kp.FromNode], ptr)
g.EdgesTo[kp.ToNode] = append(g.EdgesTo[kp.ToNode], ptr)
}
func (g nodeGraph) insertTreeRoot(sb btrfstree.Superblock, treeID btrfsprim.ObjID) {
treeInfo, err := btrfstree.LookupTreeRoot(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(kpData{
FromTree: treeID,
ToNode: treeInfo.RootNode,
ToLevel: treeInfo.Level,
ToGeneration: treeInfo.Generation,
})
}
type scanResult struct {
uuidMap
nodeGraph
}
func ScanDevices(ctx context.Context, fs *btrfs.FS, scanResults btrfsinspect.ScanDevicesResult) (*scanResult, error) {
dlog.Infof(ctx, "Reading node data from FS...")
sb, err := fs.Superblock()
if err != nil {
return nil, err
}
lastPct := -1
total := countNodes(scanResults)
done := 0
progress := func() {
pct := int(100 * float64(done) / float64(total))
if pct != lastPct || done == total {
dlog.Infof(ctx, "... %v%% (%v/%v)",
pct, done, total)
lastPct = pct
}
}
ret := &scanResult{
uuidMap: uuidMap{
ObjID2UUID: make(map[btrfsprim.ObjID]btrfsprim.UUID),
UUID2ObjID: make(map[btrfsprim.UUID]btrfsprim.ObjID),
TreeParent: make(map[btrfsprim.ObjID]btrfsprim.UUID),
SeenTrees: make(containers.Set[btrfsprim.ObjID]),
},
nodeGraph: nodeGraph{
Nodes: make(map[btrfsvol.LogicalAddr]nodeData),
BadNodes: make(map[btrfsvol.LogicalAddr]error),
EdgesFrom: make(map[btrfsvol.LogicalAddr][]*kpData),
EdgesTo: make(map[btrfsvol.LogicalAddr][]*kpData),
},
}
// These 4 trees are mentioned directly in the superblock, so
// they are always seen.
//
// 1
ret.SeenTrees.Insert(btrfsprim.ROOT_TREE_OBJECTID)
ret.insertTreeRoot(*sb, btrfsprim.ROOT_TREE_OBJECTID)
// 2
ret.SeenTrees.Insert(btrfsprim.CHUNK_TREE_OBJECTID)
ret.insertTreeRoot(*sb, btrfsprim.CHUNK_TREE_OBJECTID)
// 3
ret.SeenTrees.Insert(btrfsprim.TREE_LOG_OBJECTID)
ret.insertTreeRoot(*sb, btrfsprim.TREE_LOG_OBJECTID)
// 4
ret.SeenTrees.Insert(btrfsprim.BLOCK_GROUP_TREE_OBJECTID)
ret.insertTreeRoot(*sb, btrfsprim.BLOCK_GROUP_TREE_OBJECTID)
progress()
for _, devResults := range scanResults {
for laddr := range devResults.FoundNodes {
nodeRef, err := btrfstree.ReadNode[btrfsvol.LogicalAddr](fs, *sb, laddr, btrfstree.NodeExpectations{
LAddr: containers.Optional[btrfsvol.LogicalAddr]{OK: true, Val: laddr},
})
if err != nil {
return nil, err
}
// UUID map rebuilding
for _, item := range nodeRef.Data.BodyLeaf {
switch itemBody := item.Body.(type) {
case btrfsitem.Root:
if err := maybeSet("ObjID2UUID", ret.ObjID2UUID, item.Key.ObjectID, itemBody.UUID); err != nil {
return nil, err
}
if itemBody.UUID != (btrfsprim.UUID{}) {
if err := maybeSet("UUID2ObjID", ret.UUID2ObjID, itemBody.UUID, item.Key.ObjectID); err != nil {
return nil, err
}
}
if err := maybeSet("ParentUUID", ret.TreeParent, item.Key.ObjectID, itemBody.ParentUUID); err != nil {
return nil, err
}
ret.SeenTrees.Insert(item.Key.ObjectID)
// graph building
ret.insertEdge(kpData{
FromTree: item.Key.ObjectID,
ToNode: itemBody.ByteNr,
ToLevel: itemBody.Level,
ToGeneration: itemBody.Generation,
})
case btrfsitem.UUIDMap:
uuid := btrfsitem.KeyToUUID(item.Key)
if err := maybeSet("ObjID2UUID", ret.ObjID2UUID, itemBody.ObjID, uuid); err != nil {
return nil, err
}
if err := maybeSet("UUID2ObjID", ret.UUID2ObjID, uuid, itemBody.ObjID); err != nil {
return nil, err
}
}
}
ret.SeenTrees.Insert(nodeRef.Data.Head.Owner)
// graph building
ret.Nodes[laddr] = nodeData{
Level: nodeRef.Data.Head.Level,
Generation: nodeRef.Data.Head.Generation,
Owner: nodeRef.Data.Head.Owner,
NumItems: nodeRef.Data.Head.NumItems,
MinItem: func() btrfsprim.Key { k, _ := nodeRef.Data.MinItem(); return k }(),
MaxItem: func() btrfsprim.Key { k, _ := nodeRef.Data.MaxItem(); return k }(),
}
for i, kp := range nodeRef.Data.BodyInternal {
ret.insertEdge(kpData{
FromTree: nodeRef.Data.Head.Owner,
FromNode: laddr,
FromItem: i,
ToNode: kp.BlockPtr,
ToLevel: nodeRef.Data.Head.Level - 1,
ToKey: kp.Key,
ToGeneration: kp.Generation,
})
}
done++
progress()
}
}
if done != total {
panic("should not happen")
}
missing := ret.missingRootItems()
if len(missing) > 0 {
dlog.Errorf(ctx, "... could not find root items for %d trees: %v", len(missing), maps.SortedKeys(missing))
}
dlog.Info(ctx, "... done reading node data")
dlog.Infof(ctx, "Checking keypointers for dead-ends...")
total = len(ret.EdgesTo)
done = 0
progress()
for laddr := range ret.EdgesTo {
if _, ok := ret.Nodes[laddr]; !ok {
_, err := btrfstree.ReadNode[btrfsvol.LogicalAddr](fs, *sb, laddr, btrfstree.NodeExpectations{
LAddr: containers.Optional[btrfsvol.LogicalAddr]{OK: true, Val: laddr},
})
if err == nil {
return nil, fmt.Errorf("node@%v exists but was not in node scan results", laddr)
}
ret.BadNodes[laddr] = err
}
done++
progress()
}
dlog.Info(ctx, "... done checking keypointers")
return ret, nil
}
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