rebuildnodes: Track inode flags, to avoid later i/o

2 files changed, 38 insertions, 20 deletions

diff --git a/lib/btrfsprogs/btrfsinspect/rebuildnodes/keyio/keyio.go b/lib/btrfsprogs/btrfsinspect/rebuildnodes/keyio/keyio.go
index eb03004..64a9828 100644
--- a/lib/btrfsprogs/btrfsinspect/rebuildnodes/keyio/keyio.go
+++ b/lib/btrfsprogs/btrfsinspect/rebuildnodes/keyio/keyio.go
@@ -34,13 +34,19 @@ type SizeAndErr struct {
 	Err  error
 }
 
+type FlagsAndErr struct {
+	NoDataSum bool
+	Err       error
+}
+
 type Handle struct {
 	rawFile diskio.File[btrfsvol.LogicalAddr]
 	sb      btrfstree.Superblock
 	graph   graph.Graph
 
-	Names map[ItemPtr][]byte
-	Sizes map[ItemPtr]SizeAndErr
+	Flags map[ItemPtr]FlagsAndErr // INODE_ITEM
+	Names map[ItemPtr][]byte      // DIR_INDEX
+	Sizes map[ItemPtr]SizeAndErr  // EXTENT_CSUM and EXTENT_DATA
 
 	cache *containers.LRUCache[btrfsvol.LogicalAddr, *diskio.Ref[btrfsvol.LogicalAddr, btrfstree.Node]]
 }
@@ -50,6 +56,7 @@ func NewHandle(file diskio.File[btrfsvol.LogicalAddr], sb btrfstree.Superblock)
 		rawFile: file,
 		sb:      sb,
 
+		Flags: make(map[ItemPtr]FlagsAndErr),
 		Names: make(map[ItemPtr][]byte),
 		Sizes: make(map[ItemPtr]SizeAndErr),
 
@@ -64,6 +71,11 @@ func (o *Handle) InsertNode(nodeRef *diskio.Ref[btrfsvol.LogicalAddr, btrfstree.
 			Idx:  i,
 		}
 		switch itemBody := item.Body.(type) {
+		case btrfsitem.Inode:
+			o.Flags[ptr] = FlagsAndErr{
+				NoDataSum: itemBody.Flags.Has(btrfsitem.INODE_NODATASUM),
+				Err:       nil,
+			}
 		case btrfsitem.DirEntry:
 			if item.Key.ItemType == btrfsprim.DIR_INDEX_KEY {
 				o.Names[ptr] = append([]byte(nil), itemBody.Name...)
@@ -81,6 +93,11 @@ func (o *Handle) InsertNode(nodeRef *diskio.Ref[btrfsvol.LogicalAddr, btrfstree.
 			}
 		case btrfsitem.Error:
 			switch item.Key.ItemType {
+			case btrfsprim.INODE_ITEM_KEY:
+				o.Flags[ptr] = FlagsAndErr{
+					Err: fmt.Errorf("error decoding item: ptr=%v (tree=%v key=%v): %w",
+						ptr, nodeRef.Data.Head.Owner, item.Key, itemBody.Err),
+				}
 			case btrfsprim.EXTENT_CSUM_KEY, btrfsprim.EXTENT_DATA_KEY:
 				o.Sizes[ptr] = SizeAndErr{
 					Err: fmt.Errorf("error decoding item: ptr=%v (tree=%v key=%v): %w",
diff --git a/lib/btrfsprogs/btrfsinspect/rebuildnodes/rebuild.go b/lib/btrfsprogs/btrfsinspect/rebuildnodes/rebuild.go
index 63a0d16..fbbda26 100644
--- a/lib/btrfsprogs/btrfsinspect/rebuildnodes/rebuild.go
+++ b/lib/btrfsprogs/btrfsinspect/rebuildnodes/rebuild.go
@@ -911,27 +911,28 @@ func (o *rebuilder) wantCSum(ctx context.Context, reason string, inodeTree, inod
 		o.enqueueRetry()
 		return
 	}
-	inodeBody, ok := o.rebuilt.Tree(inodeCtx, inodeKey.TreeID).ReadItem(inodeCtx, inodeKey.Key)
+	inodePtr, ok := o.rebuilt.Tree(inodeCtx, inodeKey.TreeID).Items(inodeCtx).Load(inodeKey.Key)
 	if !ok {
-		o.ioErr(inodeCtx, fmt.Errorf("could not read previously read item: %v", inodeKey))
+		panic(fmt.Errorf("should not happen: could not load key: %v", inodeKey))
 	}
-	switch inodeBody := inodeBody.(type) {
-	case btrfsitem.Inode:
-		if inodeBody.Flags.Has(btrfsitem.INODE_NODATASUM) {
-			return
-		}
-		beg = roundDown(beg, btrfssum.BlockSize)
-		end = roundUp(end, btrfssum.BlockSize)
-		const treeID = btrfsprim.CSUM_TREE_OBJECTID
-		o._wantRange(ctx, treeID, btrfsprim.EXTENT_CSUM_OBJECTID, btrfsprim.EXTENT_CSUM_KEY,
-			uint64(beg), uint64(end))
-	case btrfsitem.Error:
-		o.fsErr(inodeCtx, fmt.Errorf("error decoding item: %v: %w", inodeKey, inodeBody.Err))
-	default:
-		// This is a panic because the item decoder should not emit INODE_ITEM items as anything but
-		// btrfsitem.Inode or btrfsitem.Error without this code also being updated.
-		panic(fmt.Errorf("should not happen: INODE_ITEM item has unexpected type: %T", inodeBody))
+	inodeFlags, ok := o.keyIO.Flags[inodePtr]
+	if !ok {
+		panic(fmt.Errorf("should not happen: INODE_ITEM did not have flags recorded"))
+	}
+	if inodeFlags.Err != nil {
+		o.fsErr(inodeCtx, inodeFlags.Err)
+		return
 	}
+
+	if inodeFlags.NoDataSum {
+		return
+	}
+
+	beg = roundDown(beg, btrfssum.BlockSize)
+	end = roundUp(end, btrfssum.BlockSize)
+	const treeID = btrfsprim.CSUM_TREE_OBJECTID
+	o._wantRange(ctx, treeID, btrfsprim.EXTENT_CSUM_OBJECTID, btrfsprim.EXTENT_CSUM_KEY,
+		uint64(beg), uint64(end))
 }
 
 // wantFileExt implements rebuildCallbacks.