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// Copyright (C) 2022 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package rebuildnodes
import (
"context"
"errors"
iofs "io/fs"
"strings"
"github.com/datawire/dlib/dlog"
"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/btrfsprogs/btrfsutil"
"git.lukeshu.com/btrfs-progs-ng/lib/diskio"
"git.lukeshu.com/btrfs-progs-ng/lib/maps"
)
type badNode struct {
Err string
Path btrfstree.TreePath
}
// classifyNodes returns
//
// 1. the set of nodes don't have another node claiming it as a child, and
// 2. the list of bad nodes (in no particular order)
func classifyNodes(ctx context.Context, fs _FS, scanResults btrfsinspect.ScanDevicesResult) (
orphanedNodes map[btrfsvol.LogicalAddr]struct{},
badNodes []badNode,
err error,
) {
dlog.Info(ctx, "Walking trees to identify orphan and broken nodes...")
lastPct := -1
total := countNodes(scanResults)
visitedNodes := make(map[btrfsvol.LogicalAddr]struct{})
progress := func() {
done := len(visitedNodes)
pct := int(100 * float64(done) / float64(total))
if pct != lastPct || done == total {
dlog.Infof(ctx, "... %v%% (%v/%v)",
pct, done, total)
lastPct = pct
}
}
walkHandler := btrfstree.TreeWalkHandler{
PreNode: func(path btrfstree.TreePath) error {
addr := path.Node(-1).ToNodeAddr
if _, alreadyVisited := visitedNodes[addr]; alreadyVisited {
// Can happen because of COW subvolumes;
// this is really a DAG not a tree.
return iofs.SkipDir
}
return nil
},
Node: func(path btrfstree.TreePath, _ *diskio.Ref[btrfsvol.LogicalAddr, btrfstree.Node]) error {
addr := path.Node(-1).ToNodeAddr
visitedNodes[addr] = struct{}{}
progress()
return nil
},
BadNode: func(path btrfstree.TreePath, _ *diskio.Ref[btrfsvol.LogicalAddr, btrfstree.Node], err error) error {
badNodes = append(badNodes, badNode{
Err: err.Error(),
Path: path.DeepCopy(),
})
return err
},
}
btrfsutil.WalkAllTrees(ctx, fs, btrfsutil.WalkAllTreesHandler{
TreeWalkHandler: walkHandler,
Err: func(err *btrfsutil.WalkError) {
// do nothing
if !errors.Is(err, btrfstree.ErrNotANode) && !strings.Contains(err.Error(), "read: could not map logical address") {
dlog.Errorf(ctx, "dbg walk err: %v", err)
}
},
})
// Start with 'orphanedRoots' as a complete set of all orphaned nodes, and then delete
// non-root entries from it.
orphanedNodes = make(map[btrfsvol.LogicalAddr]struct{})
for _, devResults := range scanResults {
for laddr := range devResults.FoundNodes {
if _, attached := visitedNodes[laddr]; !attached {
orphanedNodes[laddr] = struct{}{}
}
}
}
if len(visitedNodes)+len(orphanedNodes) != total {
panic("should not happen")
}
dlog.Infof(ctx,
"... (finished processing %v attached nodes, proceeding to process %v lost nodes, for a total of %v)",
len(visitedNodes), len(orphanedNodes), len(visitedNodes)+len(orphanedNodes))
for _, potentialRoot := range maps.SortedKeys(orphanedNodes) {
walkHandler.Node = func(path btrfstree.TreePath, _ *diskio.Ref[btrfsvol.LogicalAddr, btrfstree.Node]) error {
addr := path.Node(-1).ToNodeAddr
if addr != potentialRoot {
delete(orphanedNodes, addr)
}
visitedNodes[addr] = struct{}{}
progress()
return nil
}
walkFromNode(ctx, fs, potentialRoot,
func(err *btrfstree.TreeError) {
// do nothing
},
walkHandler,
)
}
if len(visitedNodes) != total {
panic("should not happen")
}
dlog.Infof(ctx, "... identified %d orphaned nodes and %d bad nodes", len(orphanedNodes), len(badNodes))
return orphanedNodes, badNodes, nil
}
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