diff options
Diffstat (limited to 'lib/btrfsutil')
-rw-r--r-- | lib/btrfsutil/rebuilt_forrest.go | 72 |
1 files changed, 69 insertions, 3 deletions
diff --git a/lib/btrfsutil/rebuilt_forrest.go b/lib/btrfsutil/rebuilt_forrest.go index de18080..b5c646d 100644 --- a/lib/btrfsutil/rebuilt_forrest.go +++ b/lib/btrfsutil/rebuilt_forrest.go @@ -6,6 +6,7 @@ package btrfsutil import ( "context" + "fmt" "sync" "github.com/datawire/dlib/dlog" @@ -27,6 +28,65 @@ type RebuiltForrestCallbacks interface { 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.RebuiltItems(ctx).Search(func(key btrfsprim.Key, _ ItemPtr) int { + key.Offset = 0 + return tgt.Compare(key) + }) + 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.RebuiltItems(ctx).Load(tgt) + 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)) + } +} + // RebuiltForrest is an abstraction for rebuilding and accessing // potentially broken btrees. // @@ -88,10 +148,10 @@ type RebuiltForrest struct { nodes containers.ARCache[btrfsvol.LogicalAddr, *btrfstree.Node] } -// NewRebuiltForrest returns a new RebuiltForrest instance. All of -// the callbacks must be non-nil. +// NewRebuiltForrest returns a new RebuiltForrest instance. The +// RebuiltForrestCallbacks may be nil. func NewRebuiltForrest(file diskio.File[btrfsvol.LogicalAddr], sb btrfstree.Superblock, graph Graph, cb RebuiltForrestCallbacks) *RebuiltForrest { - return &RebuiltForrest{ + ret := &RebuiltForrest{ file: file, sb: sb, graph: graph, @@ -115,6 +175,12 @@ func NewRebuiltForrest(file diskio.File[btrfsvol.LogicalAddr], sb btrfstree.Supe }, }, } + if ret.cb == nil { + ret.cb = noopRebuiltForrestCallbacks{ + forrest: ret, + } + } + return ret } // RebuiltTree returns a given tree, initializing it if nescessary. |