fusefrontend: add quirks for MacOS ExFAT

This also moves the quirks logic into fusefrontend.

Fixes https://github.com/rfjakob/gocryptfs/issues/585
master
Jakob Unterwurzacher 1 year ago
parent 75cf36fe7b
commit c3c9513e65
  1. 2
      internal/fusefrontend/file.go
  2. 2
      internal/fusefrontend/node_helpers.go
  3. 52
      internal/fusefrontend/quirks.go
  4. 4
      internal/fusefrontend/root_node.go
  5. 17
      mount.go

@ -118,7 +118,7 @@ func (f *File) createHeader() (fileID []byte, err error) {
h := contentenc.RandomHeader()
buf := h.Pack()
// Prevent partially written (=corrupt) header by preallocating the space beforehand
if !f.rootNode.args.NoPrealloc {
if !f.rootNode.args.NoPrealloc && f.rootNode.quirks&quirkBrokenFalloc == 0 {
err = syscallcompat.EnospcPrealloc(f.intFd(), 0, contentenc.HeaderLen)
if err != nil {
if !syscallcompat.IsENOSPC(err) {

@ -87,7 +87,7 @@ func (n *Node) newChild(ctx context.Context, st *syscall.Stat_t, out *fuse.Entry
out.Attr.FromStat(st)
var gen uint64 = 1
if rn.args.SharedStorage {
if rn.args.SharedStorage || rn.quirks&quirkDuplicateIno1 != 0 {
// Make each directory entry a unique node by using a unique generation
// value - see the comment at RootNode.gen for details.
gen = atomic.AddUint64(&rn.gen, 1)

@ -0,0 +1,52 @@
package fusefrontend
import (
"runtime"
"golang.org/x/sys/unix"
"github.com/rfjakob/gocryptfs/internal/tlog"
)
const (
quirkBrokenFalloc = uint64(1 << iota)
quirkDuplicateIno1
)
func detectQuirks(cipherdir string) (q uint64) {
const (
// From Linux' man statfs
BTRFS_SUPER_MAGIC = 0x9123683e
// From https://github.com/rfjakob/gocryptfs/issues/585#issuecomment-887370065
DARWIN_EXFAT_MAGIC = 35
)
var st unix.Statfs_t
err := unix.Statfs(cipherdir, &st)
if err != nil {
tlog.Warn.Printf("detectQuirks: Statfs on %q failed: %v", cipherdir, err)
return 0
}
logQuirk := func(s string) {
tlog.Info.Printf(tlog.ColorYellow + "detectQuirks: " + s + tlog.ColorReset)
}
// Preallocation on Btrfs is broken ( https://github.com/rfjakob/gocryptfs/issues/395 )
// and slow ( https://github.com/rfjakob/gocryptfs/issues/63 ).
//
// Cast to uint32 avoids compile error on arm: "constant 2435016766 overflows int32"
if uint32(st.Type) == BTRFS_SUPER_MAGIC {
logQuirk("Btrfs detected, forcing -noprealloc. See https://github.com/rfjakob/gocryptfs/issues/395 for why.")
q |= quirkBrokenFalloc
}
// On MacOS ExFAT, all empty files share inode number 1:
// https://github.com/rfjakob/gocryptfs/issues/585
if runtime.GOOS == "darwin" && st.Type == DARWIN_EXFAT_MAGIC {
logQuirk("ExFAT detected, disabling hard links. See https://github.com/rfjakob/gocryptfs/issues/585 for why.")
q |= quirkDuplicateIno1
}
return q
}

@ -57,6 +57,9 @@ type RootNode struct {
// makes go-fuse hand out separate FUSE Node IDs for each, and prevents
// bizarre problems when inode numbers are reused behind our back.
gen uint64
// quirks is a bitmap that enables workaround for quirks in the filesystem
// backing the cipherdir
quirks uint64
}
func NewRootNode(args Args, c *contentenc.ContentEnc, n *nametransform.NameTransform) *RootNode {
@ -76,6 +79,7 @@ func NewRootNode(args Args, c *contentenc.ContentEnc, n *nametransform.NameTrans
contentEnc: c,
inoMap: inomap.New(),
dirCache: dirCache{ivLen: ivLen},
quirks: detectQuirks(args.Cipherdir),
}
return rn
}

@ -19,8 +19,6 @@ import (
"syscall"
"time"
"golang.org/x/sys/unix"
"github.com/hanwen/go-fuse/v2/fs"
"github.com/hanwen/go-fuse/v2/fuse"
@ -102,21 +100,6 @@ func doMount(args *argContainer) {
}
}()
}
// Preallocation on Btrfs is broken ( https://github.com/rfjakob/gocryptfs/issues/395 )
// and slow ( https://github.com/rfjakob/gocryptfs/issues/63 ).
if !args.noprealloc {
// darwin does not have unix.BTRFS_SUPER_MAGIC, so we define it here
const BTRFS_SUPER_MAGIC = 0x9123683e
var st unix.Statfs_t
err = unix.Statfs(args.cipherdir, &st)
// Cast to uint32 avoids compile error on arm: "constant 2435016766 overflows int32"
if err == nil && uint32(st.Type) == BTRFS_SUPER_MAGIC {
tlog.Info.Printf(tlog.ColorYellow +
"Btrfs detected, forcing -noprealloc. See https://github.com/rfjakob/gocryptfs/issues/395 for why." +
tlog.ColorReset)
args.noprealloc = true
}
}
// Initialize gocryptfs (read config file, ask for password, ...)
fs, wipeKeys := initFuseFrontend(args)
// Try to wipe secret keys from memory after unmount

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