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Diffstat (limited to 'lib/btrfs/btrfstree/ops.go')
-rw-r--r--lib/btrfs/btrfstree/ops.go583
1 files changed, 0 insertions, 583 deletions
diff --git a/lib/btrfs/btrfstree/ops.go b/lib/btrfs/btrfstree/ops.go
deleted file mode 100644
index b01312f..0000000
--- a/lib/btrfs/btrfstree/ops.go
+++ /dev/null
@@ -1,583 +0,0 @@
-// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
-//
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-package btrfstree
-
-import (
- "context"
- "errors"
- "fmt"
- iofs "io/fs"
- "math"
-
- "github.com/datawire/dlib/derror"
-
- "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/btrfsvol"
- "git.lukeshu.com/btrfs-progs-ng/lib/diskio"
- "git.lukeshu.com/btrfs-progs-ng/lib/slices"
-)
-
-// TreeOperator is an interface for performing basic btree operations.
-type TreeOperator interface {
- // TreeWalk walks a tree, triggering callbacks for every node,
- // key-pointer, and item; as well as for any errors encountered.
- //
- // If the tree is valid, then everything is walked in key-order; but if
- // the tree is broken, then ordering is not guaranteed.
- //
- // Canceling the Context causes TreeWalk to return early; no
- // values from the Context are used.
- //
- // The lifecycle of callbacks is:
- //
- // 001 .PreNode()
- // 002 (read node)
- // 003 .Node() (or .BadNode())
- // for item in node.items:
- // if btrfsprim:
- // 004 .PreKeyPointer()
- // 005 (recurse)
- // 006 .PostKeyPointer()
- // else:
- // 004 .Item() (or .BadItem())
- // 007 .PostNode()
- TreeWalk(ctx context.Context, treeID btrfsprim.ObjID, errHandle func(*TreeError), cbs TreeWalkHandler)
-
- TreeLookup(treeID btrfsprim.ObjID, key btrfsprim.Key) (Item, error)
- TreeSearch(treeID btrfsprim.ObjID, fn func(key btrfsprim.Key, size uint32) int) (Item, error) // size is math.MaxUint32 for key-pointers
-
- // If some items are able to be read, but there is an error reading the
- // full set, then it might return *both* a list of items and an error.
- //
- // If no such item is found, an error that is io/fs.ErrNotExist is
- // returned.
- TreeSearchAll(treeID btrfsprim.ObjID, fn func(key btrfsprim.Key, size uint32) int) ([]Item, error) // size is math.MaxUint32 for key-pointers
-}
-
-type TreeWalkHandler struct {
- // Callbacks for entire nodes.
- //
- // If any of these return an error that is io/fs.SkipDir, the
- // node immediately stops getting processed; if PreNode, Node,
- // or BadNode return io/fs.SkipDir then key pointers and items
- // within the node are not processed.
- PreNode func(TreePath) error
- Node func(TreePath, *diskio.Ref[btrfsvol.LogicalAddr, Node]) error
- BadNode func(TreePath, *diskio.Ref[btrfsvol.LogicalAddr, Node], error) error
- PostNode func(TreePath, *diskio.Ref[btrfsvol.LogicalAddr, Node]) error
- // Callbacks for items on btrfsprim nodes
- PreKeyPointer func(TreePath, KeyPointer) error
- PostKeyPointer func(TreePath, KeyPointer) error
- // Callbacks for items on leaf nodes
- Item func(TreePath, Item) error
- BadItem func(TreePath, Item) error
-}
-
-type TreeError struct {
- Path TreePath
- Err error
-}
-
-func (e *TreeError) Unwrap() error { return e.Err }
-
-func (e *TreeError) Error() string {
- return fmt.Sprintf("%v: %v", e.Path, e.Err)
-}
-
-type NodeSource interface {
- Superblock() (*Superblock, error)
- ReadNode(TreePath) (*diskio.Ref[btrfsvol.LogicalAddr, Node], error)
-}
-
-type TreeOperatorImpl struct {
- NodeSource
-}
-
-// TreeWalk implements the 'Trees' interface.
-func (fs TreeOperatorImpl) TreeWalk(ctx context.Context, treeID btrfsprim.ObjID, errHandle func(*TreeError), cbs TreeWalkHandler) {
- sb, err := fs.Superblock()
- if err != nil {
- errHandle(&TreeError{Path: TreePath{{FromTree: treeID, ToMaxKey: btrfsprim.MaxKey}}, Err: err})
- }
- rootInfo, err := LookupTreeRoot(fs, *sb, treeID)
- if err != nil {
- errHandle(&TreeError{Path: TreePath{{FromTree: treeID, ToMaxKey: btrfsprim.MaxKey}}, Err: err})
- return
- }
- fs.RawTreeWalk(ctx, *rootInfo, errHandle, cbs)
-}
-
-// TreeWalk is a utility method to help with implementing the 'Trees'.
-// interface.
-func (fs TreeOperatorImpl) RawTreeWalk(ctx context.Context, rootInfo TreeRoot, errHandle func(*TreeError), cbs TreeWalkHandler) {
- path := TreePath{{
- FromTree: rootInfo.TreeID,
- FromItemIdx: -1,
- ToNodeAddr: rootInfo.RootNode,
- ToNodeGeneration: rootInfo.Generation,
- ToNodeLevel: rootInfo.Level,
- ToMaxKey: btrfsprim.MaxKey,
- }}
- fs.treeWalk(ctx, path, errHandle, cbs)
-}
-
-func (fs TreeOperatorImpl) treeWalk(ctx context.Context, path TreePath, errHandle func(*TreeError), cbs TreeWalkHandler) {
- if ctx.Err() != nil {
- return
- }
- if path.Node(-1).ToNodeAddr == 0 {
- return
- }
-
- if cbs.PreNode != nil {
- if err := cbs.PreNode(path); err != nil {
- if errors.Is(err, iofs.SkipDir) {
- return
- }
- errHandle(&TreeError{Path: path, Err: err})
- }
- if ctx.Err() != nil {
- return
- }
- }
- node, err := fs.ReadNode(path)
- defer FreeNodeRef(node)
- if ctx.Err() != nil {
- return
- }
- if err != nil && node != nil && cbs.BadNode != nil {
- // opportunity to fix the node
- err = cbs.BadNode(path, node, err)
- if errors.Is(err, iofs.SkipDir) {
- return
- }
- }
- if err != nil {
- errHandle(&TreeError{Path: path, Err: err})
- } else if cbs.Node != nil {
- if err := cbs.Node(path, node); err != nil {
- if errors.Is(err, iofs.SkipDir) {
- return
- }
- errHandle(&TreeError{Path: path, Err: err})
- }
- }
- if ctx.Err() != nil {
- return
- }
- if node != nil {
- for i, item := range node.Data.BodyInternal {
- toMaxKey := path.Node(-1).ToMaxKey
- if i+1 < len(node.Data.BodyInternal) {
- toMaxKey = node.Data.BodyInternal[i+1].Key.Mm()
- }
- itemPath := append(path, TreePathElem{
- FromTree: node.Data.Head.Owner,
- FromItemIdx: i,
- ToNodeAddr: item.BlockPtr,
- ToNodeGeneration: item.Generation,
- ToNodeLevel: node.Data.Head.Level - 1,
- ToKey: item.Key,
- ToMaxKey: toMaxKey,
- })
- if cbs.PreKeyPointer != nil {
- if err := cbs.PreKeyPointer(itemPath, item); err != nil {
- errHandle(&TreeError{Path: itemPath, Err: err})
- }
- if ctx.Err() != nil {
- return
- }
- }
- fs.treeWalk(ctx, itemPath, errHandle, cbs)
- if cbs.PostKeyPointer != nil {
- if err := cbs.PostKeyPointer(itemPath, item); err != nil {
- errHandle(&TreeError{Path: itemPath, Err: err})
- }
- if ctx.Err() != nil {
- return
- }
- }
- }
- for i, item := range node.Data.BodyLeaf {
- itemPath := append(path, TreePathElem{
- FromTree: node.Data.Head.Owner,
- FromItemIdx: i,
- ToKey: item.Key,
- ToMaxKey: item.Key,
- })
- if errBody, isErr := item.Body.(*btrfsitem.Error); isErr {
- if cbs.BadItem == nil {
- errHandle(&TreeError{Path: itemPath, Err: errBody.Err})
- } else {
- if err := cbs.BadItem(itemPath, item); err != nil {
- errHandle(&TreeError{Path: itemPath, Err: err})
- }
- if ctx.Err() != nil {
- return
- }
- }
- } else {
- if cbs.Item != nil {
- if err := cbs.Item(itemPath, item); err != nil {
- errHandle(&TreeError{Path: itemPath, Err: err})
- }
- if ctx.Err() != nil {
- return
- }
- }
- }
- }
- }
- if cbs.PostNode != nil {
- if err := cbs.PostNode(path, node); err != nil {
- if errors.Is(err, iofs.SkipDir) {
- return
- }
- errHandle(&TreeError{Path: path, Err: err})
- }
- }
-}
-
-func (fs TreeOperatorImpl) treeSearch(treeRoot TreeRoot, fn func(btrfsprim.Key, uint32) int) (TreePath, *diskio.Ref[btrfsvol.LogicalAddr, Node], error) {
- path := TreePath{{
- FromTree: treeRoot.TreeID,
- FromItemIdx: -1,
- ToNodeAddr: treeRoot.RootNode,
- ToNodeGeneration: treeRoot.Generation,
- ToNodeLevel: treeRoot.Level,
- ToMaxKey: btrfsprim.MaxKey,
- }}
- for {
- if path.Node(-1).ToNodeAddr == 0 {
- return nil, nil, iofs.ErrNotExist
- }
- node, err := fs.ReadNode(path)
- if err != nil {
- FreeNodeRef(node)
- return nil, nil, err
- }
-
- if node.Data.Head.Level > 0 {
- // btrfsprim node
-
- // Search for the right-most node.Data.BodyInternal item for which
- // `fn(item.Key) >= 0`.
- //
- // + + + + 0 - - - -
- //
- // There may or may not be a value that returns '0'.
- //
- // i.e. find the highest value that isn't too high.
- lastGood, ok := slices.SearchHighest(node.Data.BodyInternal, func(kp KeyPointer) int {
- return slices.Min(fn(kp.Key, math.MaxUint32), 0) // don't return >0; a key can't be "too low"
- })
- if !ok {
- FreeNodeRef(node)
- return nil, nil, iofs.ErrNotExist
- }
- toMaxKey := path.Node(-1).ToMaxKey
- if lastGood+1 < len(node.Data.BodyInternal) {
- toMaxKey = node.Data.BodyInternal[lastGood+1].Key.Mm()
- }
- path = append(path, TreePathElem{
- FromTree: node.Data.Head.Owner,
- FromItemIdx: lastGood,
- ToNodeAddr: node.Data.BodyInternal[lastGood].BlockPtr,
- ToNodeGeneration: node.Data.BodyInternal[lastGood].Generation,
- ToNodeLevel: node.Data.Head.Level - 1,
- ToKey: node.Data.BodyInternal[lastGood].Key,
- ToMaxKey: toMaxKey,
- })
- FreeNodeRef(node)
- } else {
- // leaf node
-
- // Search for a member of node.Data.BodyLeaf for which
- // `fn(item.Head.Key) == 0`.
- //
- // + + + + 0 - - - -
- //
- // Such an item might not exist; in this case, return nil/ErrNotExist.
- // Multiple such items might exist; in this case, it does not matter which
- // is returned.
- //
- // Implement this search as a binary search.
- idx, ok := slices.Search(node.Data.BodyLeaf, func(item Item) int {
- return fn(item.Key, item.BodySize)
- })
- if !ok {
- FreeNodeRef(node)
- return nil, nil, iofs.ErrNotExist
- }
- path = append(path, TreePathElem{
- FromTree: node.Data.Head.Owner,
- FromItemIdx: idx,
- ToKey: node.Data.BodyLeaf[idx].Key,
- ToMaxKey: node.Data.BodyLeaf[idx].Key,
- })
- return path, node, nil
- }
- }
-}
-
-func (fs TreeOperatorImpl) prev(path TreePath, node *diskio.Ref[btrfsvol.LogicalAddr, Node]) (TreePath, *diskio.Ref[btrfsvol.LogicalAddr, Node], error) {
- var err error
- path = path.DeepCopy()
-
- // go up
- for path.Node(-1).FromItemIdx < 1 {
- path = path.Parent()
- if len(path) == 0 {
- return nil, nil, nil
- }
- }
- // go left
- path.Node(-1).FromItemIdx--
- if path.Node(-1).ToNodeAddr != 0 {
- if node.Addr != path.Node(-2).ToNodeAddr {
- FreeNodeRef(node)
- node, err = fs.ReadNode(path.Parent())
- if err != nil {
- FreeNodeRef(node)
- return nil, nil, err
- }
- path.Node(-1).ToNodeAddr = node.Data.BodyInternal[path.Node(-1).FromItemIdx].BlockPtr
- }
- }
- // go down
- for path.Node(-1).ToNodeAddr != 0 {
- if node.Addr != path.Node(-1).ToNodeAddr {
- FreeNodeRef(node)
- node, err = fs.ReadNode(path)
- if err != nil {
- FreeNodeRef(node)
- return nil, nil, err
- }
- }
- if node.Data.Head.Level > 0 {
- path = append(path, TreePathElem{
- FromTree: node.Data.Head.Owner,
- FromItemIdx: len(node.Data.BodyInternal) - 1,
- ToNodeAddr: node.Data.BodyInternal[len(node.Data.BodyInternal)-1].BlockPtr,
- ToNodeGeneration: node.Data.BodyInternal[len(node.Data.BodyInternal)-1].Generation,
- ToNodeLevel: node.Data.Head.Level - 1,
- ToKey: node.Data.BodyInternal[len(node.Data.BodyInternal)-1].Key,
- ToMaxKey: path.Node(-1).ToMaxKey,
- })
- } else {
- path = append(path, TreePathElem{
- FromTree: node.Data.Head.Owner,
- FromItemIdx: len(node.Data.BodyLeaf) - 1,
- ToKey: node.Data.BodyLeaf[len(node.Data.BodyLeaf)-1].Key,
- ToMaxKey: node.Data.BodyLeaf[len(node.Data.BodyLeaf)-1].Key,
- })
- }
- }
- // return
- if node.Addr != path.Node(-2).ToNodeAddr {
- FreeNodeRef(node)
- node, err = fs.ReadNode(path.Parent())
- if err != nil {
- FreeNodeRef(node)
- return nil, nil, err
- }
- }
- return path, node, nil
-}
-
-func (fs TreeOperatorImpl) next(path TreePath, node *diskio.Ref[btrfsvol.LogicalAddr, Node]) (TreePath, *diskio.Ref[btrfsvol.LogicalAddr, Node], error) {
- var err error
- path = path.DeepCopy()
-
- // go up
- if node.Addr != path.Node(-2).ToNodeAddr {
- FreeNodeRef(node)
- node, err = fs.ReadNode(path.Parent())
- if err != nil {
- FreeNodeRef(node)
- return nil, nil, err
- }
- path.Node(-2).ToNodeLevel = node.Data.Head.Level
- }
- for path.Node(-1).FromItemIdx+1 >= int(node.Data.Head.NumItems) {
- path = path.Parent()
- if len(path) == 1 {
- return nil, nil, nil
- }
- if node.Addr != path.Node(-2).ToNodeAddr {
- FreeNodeRef(node)
- node, err = fs.ReadNode(path.Parent())
- if err != nil {
- FreeNodeRef(node)
- return nil, nil, err
- }
- path.Node(-2).ToNodeLevel = node.Data.Head.Level
- }
- }
- // go right
- path.Node(-1).FromItemIdx++
- if path.Node(-1).ToNodeAddr != 0 {
- if node.Addr != path.Node(-2).ToNodeAddr {
- FreeNodeRef(node)
- node, err = fs.ReadNode(path.Parent())
- if err != nil {
- FreeNodeRef(node)
- return nil, nil, err
- }
- path.Node(-1).ToNodeAddr = node.Data.BodyInternal[path.Node(-1).FromItemIdx].BlockPtr
- }
- }
- // go down
- for path.Node(-1).ToNodeAddr != 0 {
- if node.Addr != path.Node(-1).ToNodeAddr {
- FreeNodeRef(node)
- node, err = fs.ReadNode(path)
- if err != nil {
- FreeNodeRef(node)
- return nil, nil, err
- }
- path.Node(-1).ToNodeLevel = node.Data.Head.Level
- }
- if node.Data.Head.Level > 0 {
- toMaxKey := path.Node(-1).ToMaxKey
- if len(node.Data.BodyInternal) > 1 {
- toMaxKey = node.Data.BodyInternal[1].Key.Mm()
- }
- path = append(path, TreePathElem{
- FromTree: node.Data.Head.Owner,
- FromItemIdx: 0,
- ToNodeAddr: node.Data.BodyInternal[0].BlockPtr,
- ToNodeGeneration: node.Data.BodyInternal[0].Generation,
- ToNodeLevel: node.Data.Head.Level - 1,
- ToKey: node.Data.BodyInternal[0].Key,
- ToMaxKey: toMaxKey,
- })
- } else {
- path = append(path, TreePathElem{
- FromTree: node.Data.Head.Owner,
- FromItemIdx: 0,
- ToKey: node.Data.BodyInternal[0].Key,
- ToMaxKey: node.Data.BodyInternal[0].Key,
- })
- }
- }
- // return
- if node.Addr != path.Node(-2).ToNodeAddr {
- FreeNodeRef(node)
- node, err = fs.ReadNode(path.Parent())
- if err != nil {
- FreeNodeRef(node)
- return nil, nil, err
- }
- }
- return path, node, nil
-}
-
-// TreeSearch implements the 'Trees' interface.
-func (fs TreeOperatorImpl) TreeSearch(treeID btrfsprim.ObjID, fn func(btrfsprim.Key, uint32) int) (Item, error) {
- sb, err := fs.Superblock()
- if err != nil {
- return Item{}, err
- }
- rootInfo, err := LookupTreeRoot(fs, *sb, treeID)
- if err != nil {
- return Item{}, err
- }
- path, node, err := fs.treeSearch(*rootInfo, fn)
- if err != nil {
- return Item{}, err
- }
- item := node.Data.BodyLeaf[path.Node(-1).FromItemIdx]
- item.Body = item.Body.CloneItem()
- FreeNodeRef(node)
- return item, nil
-}
-
-// KeySearch returns a comparator suitable to be passed to TreeSearch.
-func KeySearch(fn func(btrfsprim.Key) int) func(btrfsprim.Key, uint32) int {
- return func(key btrfsprim.Key, _ uint32) int {
- return fn(key)
- }
-}
-
-// TreeLookup implements the 'Trees' interface.
-func (fs TreeOperatorImpl) TreeLookup(treeID btrfsprim.ObjID, key btrfsprim.Key) (Item, error) {
- item, err := fs.TreeSearch(treeID, KeySearch(key.Compare))
- if err != nil {
- err = fmt.Errorf("item with key=%v: %w", key, err)
- }
- return item, err
-}
-
-// TreeSearchAll implements the 'Trees' interface.
-func (fs TreeOperatorImpl) TreeSearchAll(treeID btrfsprim.ObjID, fn func(btrfsprim.Key, uint32) int) ([]Item, error) {
- sb, err := fs.Superblock()
- if err != nil {
- return nil, err
- }
- rootInfo, err := LookupTreeRoot(fs, *sb, treeID)
- if err != nil {
- return nil, err
- }
- middlePath, middleNode, err := fs.treeSearch(*rootInfo, fn)
- if err != nil {
- return nil, err
- }
- middleItem := middleNode.Data.BodyLeaf[middlePath.Node(-1).FromItemIdx]
-
- ret := []Item{middleItem}
- var errs derror.MultiError
- prevPath, prevNode := middlePath, middleNode
- for {
- prevPath, prevNode, err = fs.prev(prevPath, prevNode)
- if err != nil {
- errs = append(errs, err)
- break
- }
- if len(prevPath) == 0 {
- break
- }
- prevItem := prevNode.Data.BodyLeaf[prevPath.Node(-1).FromItemIdx]
- if fn(prevItem.Key, prevItem.BodySize) != 0 {
- break
- }
- item := prevItem
- item.Body = item.Body.CloneItem()
- ret = append(ret, item)
- }
- slices.Reverse(ret)
- if prevNode.Addr != middlePath.Node(-1).ToNodeAddr {
- FreeNodeRef(prevNode)
- middleNode, err = fs.ReadNode(middlePath)
- if err != nil {
- FreeNodeRef(middleNode)
- return nil, err
- }
- }
- nextPath, nextNode := middlePath, middleNode
- for {
- nextPath, nextNode, err = fs.next(nextPath, nextNode)
- if err != nil {
- errs = append(errs, err)
- break
- }
- if len(nextPath) == 0 {
- break
- }
- nextItem := nextNode.Data.BodyLeaf[nextPath.Node(-1).FromItemIdx]
- if fn(nextItem.Key, nextItem.BodySize) != 0 {
- break
- }
- item := nextItem
- item.Body = item.Body.CloneItem()
- ret = append(ret, item)
- }
- FreeNodeRef(nextNode)
- if errs != nil {
- err = errs
- }
- return ret, err
-}
generated by cgit v1.2.3-2-g168b (git 2.25.1) at 2025-05-14 22:57:44 +0000