restic/internal/fuse/fuse_test.go
greatroar a0885d5d69 fuse: Mix inode hashes in a non-symmetric way
Since 0.15 (#4020), inodes are generated as hashes of names, xor'd with
the parent inode. That means that the inode of a/b/b is

	h(a/b/b) = h(a) ^ h(b) ^ h(b) = h(a).

I.e., the grandchild has the same inode as the grandparent. GNU find
trips over this because it thinks it has encountered a loop in the
filesystem, and fails to search a/b/b. This happens more generally when
the same name occurs an even number of times.

Fix this by multiplying the parent by a large prime, so the combining
operation is not longer symmetric in its arguments. This is what the FNV
hash does, which we used prior to 0.15. The hash is now

	h(a/b/b) = h(b) ^ p*(h(b) ^ p*h(a))

Note that we already ensure that h(x) is never zero.

Collisions can still occur, but they should be much less likely to occur
within a single path.

Fixes #4253.
2023-03-21 17:33:18 +01:00

265 lines
6.8 KiB
Go

//go:build darwin || freebsd || linux
// +build darwin freebsd linux
package fuse
import (
"bytes"
"context"
"math/rand"
"os"
"testing"
"time"
"github.com/restic/restic/internal/bloblru"
"github.com/restic/restic/internal/repository"
"github.com/restic/restic/internal/restic"
"github.com/anacrolix/fuse"
"github.com/anacrolix/fuse/fs"
rtest "github.com/restic/restic/internal/test"
)
func testRead(t testing.TB, f fs.Handle, offset, length int, data []byte) {
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
req := &fuse.ReadRequest{
Offset: int64(offset),
Size: length,
}
resp := &fuse.ReadResponse{
Data: data,
}
fr := f.(fs.HandleReader)
rtest.OK(t, fr.Read(ctx, req, resp))
}
func firstSnapshotID(t testing.TB, repo restic.Repository) (first restic.ID) {
err := repo.List(context.TODO(), restic.SnapshotFile, func(id restic.ID, size int64) error {
if first.IsNull() {
first = id
}
return nil
})
if err != nil {
t.Fatal(err)
}
return first
}
func loadFirstSnapshot(t testing.TB, repo restic.Repository) *restic.Snapshot {
id := firstSnapshotID(t, repo)
sn, err := restic.LoadSnapshot(context.TODO(), repo, id)
rtest.OK(t, err)
return sn
}
func loadTree(t testing.TB, repo restic.Repository, id restic.ID) *restic.Tree {
tree, err := restic.LoadTree(context.TODO(), repo, id)
rtest.OK(t, err)
return tree
}
func TestFuseFile(t *testing.T) {
repo := repository.TestRepository(t)
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
timestamp, err := time.Parse(time.RFC3339, "2017-01-24T10:42:56+01:00")
rtest.OK(t, err)
restic.TestCreateSnapshot(t, repo, timestamp, 2, 0.1)
sn := loadFirstSnapshot(t, repo)
tree := loadTree(t, repo, *sn.Tree)
var content restic.IDs
for _, node := range tree.Nodes {
content = append(content, node.Content...)
}
t.Logf("tree loaded, content: %v", content)
var (
filesize uint64
memfile []byte
)
for _, id := range content {
size, found := repo.LookupBlobSize(id, restic.DataBlob)
rtest.Assert(t, found, "Expected to find blob id %v", id)
filesize += uint64(size)
buf, err := repo.LoadBlob(context.TODO(), restic.DataBlob, id, nil)
rtest.OK(t, err)
if len(buf) != int(size) {
t.Fatalf("not enough bytes read for id %v: want %v, got %v", id.Str(), size, len(buf))
}
if uint(len(buf)) != size {
t.Fatalf("buffer has wrong length for id %v: want %v, got %v", id.Str(), size, len(buf))
}
memfile = append(memfile, buf...)
}
t.Logf("filesize is %v, memfile has size %v", filesize, len(memfile))
node := &restic.Node{
Name: "foo",
Inode: 23,
Mode: 0742,
Size: filesize,
Content: content,
}
root := &Root{repo: repo, blobCache: bloblru.New(blobCacheSize)}
inode := inodeFromNode(1, node)
f, err := newFile(root, inode, node)
rtest.OK(t, err)
of, err := f.Open(context.TODO(), nil, nil)
rtest.OK(t, err)
attr := fuse.Attr{}
rtest.OK(t, f.Attr(ctx, &attr))
rtest.Equals(t, inode, attr.Inode)
rtest.Equals(t, node.Mode, attr.Mode)
rtest.Equals(t, node.Size, attr.Size)
rtest.Equals(t, (node.Size/uint64(attr.BlockSize))+1, attr.Blocks)
for i := 0; i < 200; i++ {
offset := rand.Intn(int(filesize))
length := rand.Intn(int(filesize)-offset) + 100
b := memfile[offset : offset+length]
buf := make([]byte, length)
testRead(t, of, offset, length, buf)
if !bytes.Equal(b, buf) {
t.Errorf("test %d failed, wrong data returned (offset %v, length %v)", i, offset, length)
}
}
}
func TestFuseDir(t *testing.T) {
repo := repository.TestRepository(t)
root := &Root{repo: repo, blobCache: bloblru.New(blobCacheSize)}
node := &restic.Node{
Mode: 0755,
UID: 42,
GID: 43,
AccessTime: time.Unix(1606773731, 0),
ChangeTime: time.Unix(1606773732, 0),
ModTime: time.Unix(1606773733, 0),
}
parentInode := inodeFromName(0, "parent")
inode := inodeFromName(1, "foo")
d, err := newDir(root, inode, parentInode, node)
rtest.OK(t, err)
// don't open the directory as that would require setting up a proper tree blob
attr := fuse.Attr{}
rtest.OK(t, d.Attr(context.TODO(), &attr))
rtest.Equals(t, inode, attr.Inode)
rtest.Equals(t, node.UID, attr.Uid)
rtest.Equals(t, node.GID, attr.Gid)
rtest.Equals(t, node.AccessTime, attr.Atime)
rtest.Equals(t, node.ChangeTime, attr.Ctime)
rtest.Equals(t, node.ModTime, attr.Mtime)
}
// Test top-level directories for their UID and GID.
func TestTopUIDGID(t *testing.T) {
repo := repository.TestRepository(t)
restic.TestCreateSnapshot(t, repo, time.Unix(1460289341, 207401672), 0, 0)
testTopUIDGID(t, Config{}, repo, uint32(os.Getuid()), uint32(os.Getgid()))
testTopUIDGID(t, Config{OwnerIsRoot: true}, repo, 0, 0)
}
func testTopUIDGID(t *testing.T, cfg Config, repo restic.Repository, uid, gid uint32) {
t.Helper()
ctx := context.Background()
root := NewRoot(repo, cfg)
var attr fuse.Attr
err := root.Attr(ctx, &attr)
rtest.OK(t, err)
rtest.Equals(t, uid, attr.Uid)
rtest.Equals(t, gid, attr.Gid)
idsdir, err := root.Lookup(ctx, "ids")
rtest.OK(t, err)
err = idsdir.Attr(ctx, &attr)
rtest.OK(t, err)
rtest.Equals(t, uid, attr.Uid)
rtest.Equals(t, gid, attr.Gid)
snapID := loadFirstSnapshot(t, repo).ID().Str()
snapshotdir, err := idsdir.(fs.NodeStringLookuper).Lookup(ctx, snapID)
rtest.OK(t, err)
// restic.TestCreateSnapshot does not set the UID/GID thus it must be always zero
err = snapshotdir.Attr(ctx, &attr)
rtest.OK(t, err)
rtest.Equals(t, uint32(0), attr.Uid)
rtest.Equals(t, uint32(0), attr.Gid)
}
func TestInodeFromNode(t *testing.T) {
node := &restic.Node{Name: "foo.txt", Type: "chardev", Links: 2}
ino1 := inodeFromNode(1, node)
ino2 := inodeFromNode(2, node)
rtest.Assert(t, ino1 == ino2, "inodes %d, %d of hard links differ", ino1, ino2)
node.Links = 1
ino1 = inodeFromNode(1, node)
ino2 = inodeFromNode(2, node)
rtest.Assert(t, ino1 != ino2, "same inode %d but different parent", ino1)
// Regression test: in a path a/b/b, the grandchild should not get the
// same inode as the grandparent.
a := &restic.Node{Name: "a", Type: "dir", Links: 2}
ab := &restic.Node{Name: "b", Type: "dir", Links: 2}
abb := &restic.Node{Name: "b", Type: "dir", Links: 2}
inoA := inodeFromNode(1, a)
inoAb := inodeFromNode(inoA, ab)
inoAbb := inodeFromNode(inoAb, abb)
rtest.Assert(t, inoA != inoAb, "inode(a/b) = inode(a)")
rtest.Assert(t, inoA != inoAbb, "inode(a/b/b) = inode(a)")
}
var sink uint64
func BenchmarkInode(b *testing.B) {
for _, sub := range []struct {
name string
node restic.Node
}{
{
name: "no_hard_links",
node: restic.Node{Name: "a somewhat long-ish filename.svg.bz2", Type: "fifo"},
},
{
name: "hard_link",
node: restic.Node{Name: "some other filename", Type: "file", Links: 2},
},
} {
b.Run(sub.name, func(b *testing.B) {
b.ReportAllocs()
for i := 0; i < b.N; i++ {
sink = inodeFromNode(1, &sub.node)
}
})
}
}