diff options
Diffstat (limited to 'lib/btrfsprogs/btrfsutil/csums.go')
-rw-r--r-- | lib/btrfsprogs/btrfsutil/csums.go | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/lib/btrfsprogs/btrfsutil/csums.go b/lib/btrfsprogs/btrfsutil/csums.go new file mode 100644 index 0000000..aad1b45 --- /dev/null +++ b/lib/btrfsprogs/btrfsutil/csums.go @@ -0,0 +1,66 @@ +// Copyright (C) 2022 Luke Shumaker <lukeshu@lukeshu.com> +// +// SPDX-License-Identifier: GPL-2.0-or-later + +package btrfsutil + +import ( + "fmt" + + "git.lukeshu.com/btrfs-progs-ng/lib/btrfs" + "git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsitem" + "git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfssum" + "git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol" +) + +func ChecksumLogical(fs btrfs.Trees, alg btrfssum.CSumType, laddr btrfsvol.LogicalAddr) (btrfssum.CSum, error) { + var dat [btrfsitem.CSumBlockSize]byte + if _, err := fs.ReadAt(dat[:], laddr); err != nil { + return btrfssum.CSum{}, err + } + return alg.Sum(dat[:]) +} + +func ChecksumPhysical(dev *btrfs.Device, alg btrfssum.CSumType, paddr btrfsvol.PhysicalAddr) (btrfssum.CSum, error) { + var dat [btrfsitem.CSumBlockSize]byte + if _, err := dev.ReadAt(dat[:], paddr); err != nil { + return btrfssum.CSum{}, err + } + return alg.Sum(dat[:]) +} + +func ChecksumQualifiedPhysical(fs *btrfs.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 btrfs.Trees, alg btrfssum.CSumType, laddr btrfsvol.LogicalAddr) (map[btrfsvol.LogicalAddr]btrfssum.CSum, error) { + item, err := fs.TreeSearch(btrfs.CSUM_TREE_OBJECTID, func(key btrfs.Key, size uint32) int { + itemBeg := btrfsvol.LogicalAddr(key.ObjectID) + numSums := int64(size) / int64(alg.Size()) + itemEnd := itemBeg + btrfsvol.LogicalAddr(numSums*btrfsitem.CSumBlockSize) + switch { + case itemEnd <= laddr: + return 1 + case laddr < itemBeg: + return -1 + default: + return 0 + } + }) + if err != nil { + return nil, err + } + body, ok := item.Body.(btrfsitem.ExtentCSum) + if !ok { + return nil, fmt.Errorf("item body is %T not ExtentCSum", item.Body) + } + ret := make(map[btrfsvol.LogicalAddr]btrfssum.CSum, len(body.Sums)) + for i, sum := range body.Sums { + ret[btrfsvol.LogicalAddr(item.Key.ObjectID)+(btrfsvol.LogicalAddr(i)*btrfsitem.CSumBlockSize)] = sum + } + return ret, nil +} |