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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"
"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"
)
type ItemPtr struct {
Node btrfsvol.LogicalAddr
Slot int
}
func (ptr ItemPtr) String() string {
return fmt.Sprintf("node@%v[%v]", ptr.Node, ptr.Slot)
}
func (ts *RebuiltForrest) readItem(ctx context.Context, ptr ItemPtr) btrfsitem.Item {
graphInfo, ok := ts.graph.Nodes[ptr.Node]
if !ok {
panic(fmt.Errorf("should not happen: btrfsutil.RebuiltForrest.readItem called for node@%v not mentioned in the in-memory graph", ptr.Node))
}
if graphInfo.Level != 0 {
panic(fmt.Errorf("should not happen: btrfsutil.RebuiltForrest.readItem called for non-leaf node@%v", ptr.Node))
}
if ptr.Slot < 0 {
panic(fmt.Errorf("should not happen: btrfsutil.RebuiltForrest.readItem called for negative item slot: %v", ptr.Slot))
}
node, err := ts.file.AcquireNode(ctx, ptr.Node, btrfstree.NodeExpectations{
LAddr: containers.OptionalValue(ptr.Node),
Level: containers.OptionalValue(graphInfo.Level),
Generation: containers.OptionalValue(graphInfo.Generation),
Owner: func(treeID btrfsprim.ObjID, gen btrfsprim.Generation) error {
if treeID != graphInfo.Owner || gen != graphInfo.Generation {
return fmt.Errorf("expected owner=%v generation=%v but claims to have owner=%v generation=%v",
graphInfo.Owner, graphInfo.Generation,
treeID, gen)
}
return nil
},
MinItem: containers.OptionalValue(graphInfo.MinItem()),
MaxItem: containers.OptionalValue(graphInfo.MaxItem()),
})
defer ts.file.ReleaseNode(node)
if err != nil {
panic(fmt.Errorf("should not happen: i/o error: %w", err))
}
items := node.BodyLeaf
if ptr.Slot >= len(items) {
panic(fmt.Errorf("should not happen: btrfsutil.RebuiltForrest.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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