Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Remove the support for using non-mpsafe filesystem modules.

In particular, do not lock Giant conditionally when calling into the
filesystem module, remove the VFS_LOCK_GIANT() and related
macros. Stop handling buffers belonging to non-mpsafe filesystems.

The VFS_VERSION is bumped to indicate the interface change which does
not result in the interface signatures changes.

Conducted and reviewed by: attilio
Tested by: pho

Fix found places where uio_resid is truncated to int.

Add the sysctl debug.iosize_max_clamp, enabled by default. Setting the
sysctl to zero allows to perform the SSIZE_MAX-sized i/o requests from
the usermode.

Discussed with: bde, das (previous versions)
MFC after: 1 month

The in-kernel CTF parser caches the result of its first attempt to parse
CTF data from a module. On subsequent attempts to retrieve CTF data for
a module, return an error if there no CTF data.

This fixes a panic if you try to enable fbt probes on a module with CTF
data twice.

Submitted by: Paul Ambrose (ambrosehua AT gmail DOT com)
MFC after: 3 days

Return proper errno when we hit error when doing sanity check.
This fixes dtrace crashes when module is not compiled with CTF
data.

Submitted by: Paul Ambrose ambrosehua at gmail.com
MFC after: 1 week

Add the CTF source file which gets shared with link_elf.c and link_elf_obj.c.