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// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package btrfs
import (
"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/btrfssum"
"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"
)
// dat doesn't escape to the heap in .ReadAt(dat, …), but the compiler
// can't figure that out, so we use a Pool for our byte arrays, since
// the compiler won't let us allocate them on the stack.
var blockPool containers.SlicePool[byte]
func ChecksumLogical(fs diskio.File[btrfsvol.LogicalAddr], alg btrfssum.CSumType, laddr btrfsvol.LogicalAddr) (btrfssum.CSum, error) {
dat := blockPool.Get(btrfssum.BlockSize)
defer blockPool.Put(dat)
if _, err := fs.ReadAt(dat, laddr); err != nil {
return btrfssum.CSum{}, err
}
return alg.Sum(dat)
}
func ChecksumPhysical(dev *Device, alg btrfssum.CSumType, paddr btrfsvol.PhysicalAddr) (btrfssum.CSum, error) {
dat := blockPool.Get(btrfssum.BlockSize)
defer blockPool.Put(dat)
if _, err := dev.ReadAt(dat, paddr); err != nil {
return btrfssum.CSum{}, err
}
return alg.Sum(dat)
}
func ChecksumQualifiedPhysical(fs *FS, alg btrfssum.CSumType, paddr btrfsvol.QualifiedPhysicalAddr) (btrfssum.CSum, error) {
dev := fs.LV.PhysicalVolumes()[paddr.Dev]
if dev == nil {
return btrfssum.CSum{}, fmt.Errorf("no such device_id=%v", paddr.Dev)
}
return ChecksumPhysical(dev, alg, paddr.Addr)
}
func LookupCSum(fs btrfstree.TreeOperator, alg btrfssum.CSumType, laddr btrfsvol.LogicalAddr) (btrfssum.SumRun[btrfsvol.LogicalAddr], error) {
item, err := fs.TreeSearch(btrfsprim.CSUM_TREE_OBJECTID, btrfstree.SearchCSum(laddr, alg.Size()))
if err != nil {
return btrfssum.SumRun[btrfsvol.LogicalAddr]{}, err
}
if item.Key.ItemType != btrfsitem.EXTENT_CSUM_KEY {
return btrfssum.SumRun[btrfsvol.LogicalAddr]{}, fmt.Errorf("item type is %v, not EXTENT_CSUM", item.Key.ItemType)
}
switch body := item.Body.(type) {
case *btrfsitem.ExtentCSum:
return body.SumRun, nil
case *btrfsitem.Error:
return btrfssum.SumRun[btrfsvol.LogicalAddr]{}, body.Err
default:
panic(fmt.Errorf("should not happen: EXTENT_CSUM has unexpected item type: %T", body))
}
}
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