Copy stable/11@r303970 to releng/11.0 as part of the 11.0-RELEASE
cycle.

Prune svn:mergeinfo from the new branch, and rename it to RC1.

Update __FreeBSD_version.

Use the quarterly branch for the default FreeBSD.conf pkg(8) repo and
the dvd1.iso packages population.

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

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Move zlib.c from net to libkern.

It is not network-specific code and would
be better as part of libkern instead.
Move zlib.h and zutil.h from net/ to sys/
Update includes to use sys/zlib.h and sys/zutil.h instead of net/

Submitted by: Steve Kiernan stevek@juniper.net
Obtained from: Juniper Networks, Inc.
GitHub Pull Request: https://github.com/freebsd/freebsd/pull/28
Relnotes: yes

Reimplement support for userland core dump compression using a new interface
in kern_gzio.c. The old gzio interface was somewhat inflexible and has not
worked properly since r272535: currently, the gzio functions are called with
a range lock held on the output vnode, but kern_gzio.c does not pass the
IO_RANGELOCKED flag to vn_rdwr() calls, resulting in deadlock when vn_rdwr()
attempts to reacquire the range lock. Moreover, the new gzio interface can
be used to implement kernel core compression.

This change also modifies the kernel configuration options needed to enable
userland core dump compression support: gzio is now an option rather than a
device, and the COMPRESS_USER_CORES option is removed. Core dump compression
is enabled using the kern.compress_user_cores sysctl/tunable.

Differential Revision: https://reviews.freebsd.org/D1832
Reviewed by: rpaulo
Discussed with: kib

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

Do not set IO_NODELOCKED while writing to vnodes as our consumers
do not lock the vnodes.

Obtained from: Juniper Networks

Reviewed by: jhb

Merge projects/enhanced_coredumps (r204346) into HEAD:

Enhanced process coredump routines.

This brings in the following features:
1) Limit number of cores per process via the %I coredump formatter.
Example:
if corefilename is set to %N.%I.core AND num_cores = 3, then
if a process "rpd" cores, then the corefile will be named
"rpd.0.core", however if it cores again, then the kernel will
generate "rpd.1.core" until we hit the limit of "num_cores".

this is useful to get several corefiles, but also prevent filling
the machine with corefiles.

2) Encode machine hostname in core dump name via %H.

3) Compress coredumps, useful for embedded platforms with limited space.
A sysctl kern.compress_user_cores is made available if turned on.

To enable compressed coredumps, the following config options need to be set:
options COMPRESS_USER_CORES
device zlib # brings in the zlib requirements.
device gzio # brings in the kernel vnode gzip output module.

4) Eventhandlers are fired to indicate coredumps in progress.

5) The imgact sv_coredump routine has grown a flag to pass in more
state, currently this is used only for passing a flag down to compress
the coredump or not.

Note that the gzio facility can be used for generic output of gzip'd
streams via vnodes.

Obtained from: Juniper Networks
Reviewed by: kan