fsmap.h: add linux/fsmap.h to UAPI compile-test coverage

linux/fsmap.h is currently excluded from the UAPI compile-test because
of the error like follows:

HDRTEST usr/include/linux/fsmap.h
In file included from <command-line>:
./usr/include/linux/fsmap.h:72:19: error: unknown type name ‘size_t’
72 | static __inline__ size_t
| ^~~~~~

The error can be fixed by replacing size_t with __kernel_size_t.

Then, remove the no-header-test entry from user/include/Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

License cleanup: add SPDX license identifier to uapi header files with no license

Many user space API headers are missing licensing information, which
makes it hard for compliance tools to determine the correct license.

By default are files without license information under the default
license of the kernel, which is GPLV2. Marking them GPLV2 would exclude
them from being included in non GPLV2 code, which is obviously not
intended. The user space API headers fall under the syscall exception
which is in the kernels COPYING file:

NOTE! This copyright does *not* cover user programs that use kernel
services by normal system calls - this is merely considered normal use
of the kernel, and does *not* fall under the heading of "derived work".

otherwise syscall usage would not be possible.

Update the files which contain no license information with an SPDX
license identifier. The chosen identifier is 'GPL-2.0 WITH
Linux-syscall-note' which is the officially assigned identifier for the
Linux syscall exception. SPDX license identifiers are a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne. See the previous patch in this series for the
methodology of how this patch was researched.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fsmap: fix documentation of FMR_OF_LAST

The FMR_OF_LAST flag is set on the last fsmap record being returned for
the dataset requested, contrary to what the header file says. Fix the
docs to reflect the behavior of all fsmap implementations.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

vfs: add common GETFSMAP ioctl definitions

Add the GETFSMAP headers to the VFS kernel headers

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

vfs: add common GETFSMAP ioctl definitions

Add the GETFSMAP headers to the VFS kernel headers

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>