samples/vfs: avoid warning in statx override

Something changed recently to uncover this warning:

samples/vfs/test-statx.c:24:15: warning: `struct foo' declared inside parameter list will not be visible outside of this definition or declaration
24 | #define statx foo
| ^~~

Which is due the use of "struct statx" (here, "struct foo") in a function
prototype argument list before it has been defined:

int
# 56 "/usr/include/x86_64-linux-gnu/bits/statx-generic.h"
foo
# 56 "/usr/include/x86_64-linux-gnu/bits/statx-generic.h" 3 4
(int __dirfd, const char *__restrict __path, int __flags,
unsigned int __mask, struct
# 57 "/usr/include/x86_64-linux-gnu/bits/statx-generic.h"
foo
# 57 "/usr/include/x86_64-linux-gnu/bits/statx-generic.h" 3 4
*__restrict __buf)
__attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (2, 5)));

Add explicit struct before #include to avoid warning.

Fixes: f1b5618e013a ("vfs: Add a sample program for the new mount API")
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: David Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/202006282213.C516EA6@keescook
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

uapi: deprecate STATX_ALL

Constants of the *_ALL type can be actively harmful due to the fact that
developers will usually fail to consider the possible effects of future
changes to the definition.

Deprecate STATX_ALL in the uapi, while no damage has been done yet.

We could keep something like this around in the kernel, but there's
actually no point, since all filesystems should be explicitly checking
flags that they support and not rely on the VFS masking unknown ones out: a
flag could be known to the VFS, yet not known to the filesystem.

Cc: David Howells <dhowells@redhat.com>
Cc: linux-api@vger.kernel.org
Cc: linux-man@vger.kernel.org
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public licence as published by
the free software foundation either version 2 of the licence or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 114 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170857.552531963@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

vfs: Add a sample program for the new mount API

Add a sample program to demonstrate fsopen/fsmount/move_mount to mount
something.

To make it compile on all arches, irrespective of whether or not syscall
numbers are assigned, define the syscall number to -1 if it isn't to cause
the kernel to return -ENOSYS.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>