v2api: -sharestorage: disable hard link tracking & add tests

Hard link tracking was not correctly disabled
since the migration to the go-fuse v2 api.

Add a test to ensure it stays off.

Fixes https://github.com/rfjakob/gocryptfs/issues/525
libgocryptfs
Jakob Unterwurzacher 2 years ago
parent eaca820e87
commit e2dc52a965
  1. 3
      internal/fusefrontend/args.go
  2. 3
      internal/fusefrontend/node_helpers.go
  3. 10
      internal/fusefrontend/root_node.go
  4. 11
      internal/inomap/inomap.go
  5. 10
      mount.go
  6. 47
      tests/cli/cli_test.go

@ -46,4 +46,7 @@ type Args struct {
Suid bool
// Enable the FUSE kernel_cache option
KernelCache bool
// SharedStorage disables caching & hard link tracking,
// enabled via cli flag "-sharedstorage"
SharedStorage bool
}

@ -102,8 +102,9 @@ func (n *Node) prepareAtSyscall(child string) (dirfd int, cName string, errno sy
// newChild attaches a new child inode to n.
// The passed-in `st` will be modified to get a unique inode number.
func (n *Node) newChild(ctx context.Context, st *syscall.Stat_t, out *fuse.EntryOut) *fs.Inode {
// Get unique inode number
rn := n.rootNode()
// Get stable inode number based on underlying (device,ino) pair
// (or set to zero in case of `-sharestorage`)
rn.inoMap.TranslateStat(st)
out.Attr.FromStat(st)
// Create child node

@ -50,7 +50,7 @@ type RootNode struct {
IsIdle uint32
// inoMap translates inode numbers from different devices to unique inode
// numbers.
inoMap *inomap.InoMap
inoMap inomap.TranslateStater
}
func NewRootNode(args Args, c *contentenc.ContentEnc, n nametransform.NameTransformer) *RootNode {
@ -60,12 +60,18 @@ func NewRootNode(args Args, c *contentenc.ContentEnc, n nametransform.NameTransf
if len(args.Exclude) > 0 {
tlog.Warn.Printf("Forward mode does not support -exclude")
}
return &RootNode{
rn := &RootNode{
args: args,
nameTransform: n,
contentEnc: c,
inoMap: inomap.New(),
}
// In `-sharedstorage` mode we always set the inode number to zero.
// This makes go-fuse generate a new inode number for each lookup.
if args.SharedStorage {
rn.inoMap = &inomap.TranslateStatZero{}
}
return rn
}
// mangleOpenFlags is used by Create() and Open() to convert the open flags the user

@ -104,3 +104,14 @@ func (m *InoMap) TranslateStat(st *syscall.Stat_t) {
in := QInoFromStat(st)
st.Ino = m.Translate(in)
}
type TranslateStater interface {
TranslateStat(st *syscall.Stat_t)
}
// TranslateStatZero always sets st.Ino to zero. Used for `-sharedstorage`.
type TranslateStatZero struct{}
func (z TranslateStatZero) TranslateStat(st *syscall.Stat_t) {
st.Ino = 0
}

@ -280,6 +280,7 @@ func initFuseFrontend(args *argContainer) (rootNode fs.InodeEmbedder, wipeKeys f
ExcludeFrom: args.excludeFrom,
Suid: args.suid,
KernelCache: args.kernel_cache,
SharedStorage: args.sharedstorage,
}
// confFile is nil when "-zerokey" or "-masterkey" was used
if confFile != nil {
@ -349,7 +350,11 @@ func initGoFuse(rootNode fs.InodeEmbedder, args *argContainer) *fuse.Server {
if args.sharedstorage {
// sharedstorage mode sets all cache timeouts to zero so changes to the
// backing shared storage show up immediately.
fuseOpts = &fs.Options{}
// Hard links are disabled by using automatically incrementing
// inode numbers provided by go-fuse.
fuseOpts = &fs.Options{
FirstAutomaticIno: 1000,
}
} else {
fuseOpts = &fs.Options{
// These options are to be compatible with libfuse defaults,
@ -421,7 +426,8 @@ func initGoFuse(rootNode fs.InodeEmbedder, args *argContainer) *fuse.Server {
} else if args.rw {
mOpts.Options = append(mOpts.Options, "rw")
}
// If both "nosuid" and "suid" were passed, the safer option wins.
// If both "nosuid" & "suid", "nodev" & "dev", etc were passed, the safer
// option wins.
if args.nosuid {
mOpts.Options = append(mOpts.Options, "nosuid")
} else if args.suid {

@ -822,3 +822,50 @@ func TestInitNotEmpty(t *testing.T) {
t.Fatalf("wrong exit code: have=%d, want=%d", exitCode, exitcodes.CipherDir)
}
}
// TestSharedstorage checks that `-sharedstorage` hands out arbitrary inode
// numbers (no hard link tracking)
func TestSharedstorage(t *testing.T) {
dir := test_helpers.InitFS(t)
mnt := dir + ".mnt"
err := os.Mkdir(mnt, 0700)
if err != nil {
t.Fatal(err)
}
test_helpers.MountOrFatal(t, dir, mnt, "-extpass=echo test", "-sharedstorage")
defer test_helpers.UnmountPanic(mnt)
foo1 := mnt + "/foo1"
foo2 := mnt + "/foo2"
if err := ioutil.WriteFile(foo1, nil, 0755); err != nil {
t.Fatal(err)
}
if err := os.Link(foo1, foo2); err != nil {
t.Fatal(err)
}
var st1, st2, st3 syscall.Stat_t
if err := syscall.Stat(foo1, &st1); err != nil {
t.Fatal(err)
}
// The link show show a new inode number
if err := syscall.Stat(foo2, &st2); err != nil {
t.Fatal(err)
}
// Stat()'ing again should give us again a new inode number
if err := syscall.Stat(foo2, &st3); err != nil {
t.Fatal(err)
}
if st1.Ino == st2.Ino || st2.Ino == st3.Ino || st1.Ino == st3.Ino {
t.Error(st1.Ino, st2.Ino, st3.Ino)
}
// Check that we we don't have stat caching. New length should show up
// on the hard link immediately.
if err := ioutil.WriteFile(foo1, []byte("xxxxxx"), 0755); err != nil {
t.Fatal(err)
}
if err := syscall.Stat(foo2, &st2); err != nil {
t.Fatal(err)
}
if st2.Size != 6 {
t.Fatal(st2.Size)
}
}

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