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// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package btrfsutil
import (
"context"
"fmt"
"sync"
"github.com/datawire/dlib/dlog"
"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/containers"
"git.lukeshu.com/btrfs-progs-ng/lib/diskio"
"git.lukeshu.com/btrfs-progs-ng/lib/textui"
)
type ItemPtr struct {
Node btrfsvol.LogicalAddr
Slot int
}
func (ptr ItemPtr) String() string {
return fmt.Sprintf("node@%v[%v]", ptr.Node, ptr.Slot)
}
type SizeAndErr struct {
Size uint64
Err error
}
type FlagsAndErr struct {
NoDataSum bool
Err error
}
type KeyIO struct {
rawFile diskio.File[btrfsvol.LogicalAddr]
sb btrfstree.Superblock
graph Graph
Flags map[ItemPtr]FlagsAndErr // INODE_ITEM
Names map[ItemPtr][]byte // DIR_INDEX
Sizes map[ItemPtr]SizeAndErr // EXTENT_CSUM and EXTENT_DATA
mu sync.Mutex
cache containers.ARCache[btrfsvol.LogicalAddr, *diskio.Ref[btrfsvol.LogicalAddr, btrfstree.Node]]
}
func NewKeyIO(file diskio.File[btrfsvol.LogicalAddr], sb btrfstree.Superblock) *KeyIO {
return &KeyIO{
rawFile: file,
sb: sb,
Flags: make(map[ItemPtr]FlagsAndErr),
Names: make(map[ItemPtr][]byte),
Sizes: make(map[ItemPtr]SizeAndErr),
cache: containers.ARCache[btrfsvol.LogicalAddr, *diskio.Ref[btrfsvol.LogicalAddr, btrfstree.Node]]{
MaxLen: textui.Tunable(8),
OnRemove: func(_ btrfsvol.LogicalAddr, nodeRef *diskio.Ref[btrfsvol.LogicalAddr, btrfstree.Node]) {
btrfstree.FreeNodeRef(nodeRef)
},
},
}
}
func (o *KeyIO) InsertNode(nodeRef *diskio.Ref[btrfsvol.LogicalAddr, btrfstree.Node]) {
for i, item := range nodeRef.Data.BodyLeaf {
ptr := ItemPtr{
Node: nodeRef.Addr,
Slot: 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...)
}
case *btrfsitem.ExtentCSum:
o.Sizes[ptr] = SizeAndErr{
Size: uint64(itemBody.Size()),
Err: nil,
}
case *btrfsitem.FileExtent:
size, err := itemBody.Size()
o.Sizes[ptr] = SizeAndErr{
Size: uint64(size),
Err: err,
}
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",
ptr, nodeRef.Data.Head.Owner, item.Key, itemBody.Err),
}
}
}
}
}
func (o *KeyIO) SetGraph(graph Graph) {
o.graph = graph
}
func (o *KeyIO) readNode(ctx context.Context, laddr btrfsvol.LogicalAddr) *diskio.Ref[btrfsvol.LogicalAddr, btrfstree.Node] {
if cached, ok := o.cache.Load(laddr); ok {
dlog.Tracef(ctx, "cache-hit node@%v", laddr)
return cached
}
graphInfo, ok := o.graph.Nodes[laddr]
if !ok {
panic(fmt.Errorf("should not happen: node@%v is not mentioned in the in-memory graph", laddr))
}
dlog.Debugf(ctx, "cache-miss node@%v, reading...", laddr)
ref, err := btrfstree.ReadNode(o.rawFile, o.sb, laddr, btrfstree.NodeExpectations{
LAddr: containers.Optional[btrfsvol.LogicalAddr]{OK: true, Val: laddr},
Level: containers.Optional[uint8]{OK: true, Val: graphInfo.Level},
Generation: containers.Optional[btrfsprim.Generation]{OK: true, Val: graphInfo.Generation},
Owner: func(treeID btrfsprim.ObjID) error {
if treeID != graphInfo.Owner {
return fmt.Errorf("expected owner=%v but claims to have owner=%v",
graphInfo.Owner, treeID)
}
return nil
},
MinItem: containers.Optional[btrfsprim.Key]{OK: true, Val: graphInfo.MinItem()},
MaxItem: containers.Optional[btrfsprim.Key]{OK: true, Val: graphInfo.MaxItem()},
})
if err != nil {
panic(fmt.Errorf("should not happen: i/o error: %w", err))
}
o.cache.Store(laddr, ref)
return ref
}
func (o *KeyIO) ReadItem(ctx context.Context, ptr ItemPtr) btrfsitem.Item {
o.mu.Lock()
defer o.mu.Unlock()
if o.graph.Nodes[ptr.Node].Level != 0 {
panic(fmt.Errorf("should not happen: btrfsutil.KeyIO.ReadItem called for non-leaf node@%v", ptr.Node))
}
if ptr.Slot < 0 {
panic(fmt.Errorf("should not happen: btrfsutil.KeyIO.ReadItem called for negative item slot: %v", ptr.Slot))
}
items := o.readNode(ctx, ptr.Node).Data.BodyLeaf
if ptr.Slot >= len(items) {
panic(fmt.Errorf("should not happen: btrfsutil.KeyIO.ReadItem called for out-of-bounds item slot: slot=%v len=%v",
ptr.Slot, len(items)))
}
return items[ptr.Slot].Body.CloneItem()
}
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