* master:
  fixup! rename NodeAttr to StableAttr
  rename NodeAttr to StableAttr
  internal: fix access for root user
  tarfs: handle empty directories, handle more file types
  nodefs: add Attr to MemSymlink
  nodefs: protect dirsteam overflow with lock
  nodefs: add TestReadDirStress
  nodefs: protect against double close
  newunionfs: run PosixTest tests.
  newunionfs: symlink/readlink
  posixtest: export list of tests
  nodefs: handle unimplemented Mkdir
  newunionfs: a new unionfs implementation
  fuse: fix SupportsVersion
  nodefs: skip tests if kernel doesn't support lseek/copy_file_range
  posixtest: new package for generic file system tests
  update go modules.
  nodefs: add EntryOut to Create signature
  nodefs: add Inode.IsDir
  nodefs: implement Setattr in loopback

I saw build error when running tests:

	(neo) (z-dev) (g.env) kirr@deco:~/src/neo/src/github.com/hanwen/go-fuse$ go test ./...
	# github.com/hanwen/go-fuse/nodefs
	nodefs/inode.go:130:30: undefined: NodeAttr
	FAIL    github.com/hanwen/go-fuse/benchmark [build failed]
	...

Appeases the race detector.

This currently fails on Linux 5.0 and may be related to
https://github.com/hanwen/go-fuse/issues/287 .

1 jakob@brikett:~/go/src/github.com/hanwen/go-fuse/nodefs$ go test
21:42:47.356529 writer: Write/Writev failed, err: 2=no such file or directory. opcode: RELEASE
21:42:47.598309 writer: Write/Writev failed, err: 22=invalid argument. opcode: READDIRPLUS
21:42:47.604424 writer: Write/Writev failed, err: 22=invalid argument. opcode: READDIRPLUS
21:42:47.606073 writer: Write/Writev failed, err: 22=invalid argument. opcode: READDIRPLUS
--- FAIL: TestReadDirStress (0.36s)
    simple_test.go:270: goroutine 2 iteration 5: readdirent: input/output error
    simple_test.go:270: goroutine 1 iteration 9: readdirent: input/output error
    simple_test.go:270: goroutine 3 iteration 10: readdirent: input/output error
    simple_test.go:43: /usr/bin/fusermount: entry for /tmp/TestReadDirStress639795934/mnt not found in /etc/mtab
         (code exit status 1)

FAIL
exit status 1
FAIL	github.com/hanwen/go-fuse/nodefs	0.994s

Access file descriptors under lock, and set to -1 on close. This
avoids confusing errors if Close() is doubly called

This is based on the new nodefs API, and tests the new API for writing
a full-fledged r/w filesystem.

* origin/master: (28 commits)
  nodefs: use offset for MemRegularFile reads. Test it.
  zipfs: fix and test tarfs
  nodefs: don't tweak MemRegularFile mode
  nodefs: fix builds on darwin
  example/hello: convert hello to new nodefs API
  nodefs: add MemRegularFile.Flush
  example/statfs: use new nodefs library
  example/loopback: use new nodefs library
  nodefs: document Access
  example/zipfs: use new nodefs
  nodefs: use bridge.getattr for Access calculation
  example/multizip: use new nodefs package.
  nodefs: comment ExampleNewPersistentInode
  nodefs: add Options.DefaultPermissions
  zipfs: rewrite using new nodefs API.
  nodefs: use testMount in tests
  nodefs: don't pass root into Options.OnAdd
  nodefs: add Inode.RmAllChildren
  nodefs: various fixes
  nodefs: check that default Create returns EROFS
  ...

Together with DefaultPermissions, this lets you cd into a nodefs
powered file system.

Remove memtree.

Add an example for constructing an in-memory file system