Remove cross-references to GBDE

sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

bufcache: convert bo_numoutput from long to int

int is wide enough and it plugs a hole in struct vnode, taking it down
from 496 to 488 bytes.

Add a new "mntfs" pseudo file system which provides private device vnodes for
file systems to safely access their disk devices, and adapt FFS to use it.
Also add a new BO_NOBUFS flag to allow enforcing that file systems using
mntfs vnodes do not accidentally use the original devfs vnode to create buffers.

Reviewed by: kib, mckusick
Approved by: imp (mentor)
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D23787

sys/kern: quiet -Wwrite-strings

Quiet a variety of Wwrite-strings warnings in sys/kern at low-impact
sites. This patch avoids addressing certain others which would need to
plumb const through structure definitions.

Reviewed by: kib, markj
Differential Revision: https://reviews.freebsd.org/D23798

sys/bufobj.h: Avoid using C++ reserved keyword 'private'

No functional change (except for out-of-tree C++ kmods).

Further parallelize the buffer cache.

Provide multiple clean queues partitioned into 'domains'. Each domain manages
its own bufspace and has its own bufspace daemon. Each domain has a set of
subqueues indexed by the current cpuid to reduce lock contention on the cleanq.

Refine the sleep/wakeup around the bufspace daemon to use atomics as much as
possible.

Add a B_REUSE flag that is used to requeue bufs during the scan to approximate
LRU rather than locking the queue on every use of a frequently accessed buf.

Implement bufspace_reserve with only atomic_fetchadd to avoid loop restarts.

Reviewed by: markj
Tested by: pho
Sponsored by: Netflix, Dell/EMC Isilon
Differential Revision: https://reviews.freebsd.org/D14274

sys/sys: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Document what the different flags mean for locking.

vfs: remove the __bo_vnode field from struct vnode

The pointer can be obtained using __containerof instead.

Reviewed by: kib

The vinactive() call in vgonel() may start writes for the dirty pages,
creating delayed write buffers belonging to the reclaimed vnode. Put
the buffer cleanup code after inactivation.

Add asserts that ensure that buffer queues are empty and add BO_DEAD
flag for bufobj to check that no buffers are added after the cleanup.
BO_DEAD is only used by INVARIANTS-enabled kernels.

Reported and tested by: pho (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

Fix comment after r250551.

- Convert the bufobj lock to rwlock.
- Use a shared bufobj lock in getblk() and inmem().
- Convert softdep's lk to rwlock to match the bufobj lock.
- Move INFREECNT to b_flags and protect it with the buf lock.
- Remove unnecessary locking around bremfree() and BKGRDINPROG.

Sponsored by: EMC / Isilon Storage Division
Discussed with: mckusick, kib, mdf

- Add a new general purpose path-compressed radix trie which can be used
with any structure containing a uint64_t index. The tree code
auto-generates type safe wrappers.
- Eliminate the buf splay and replace it with pctrie. This is not only
significantly faster with large files but also allows for the possibility
of shared locking.

Reviewed by: alc, attilio
Sponsored by: EMC / Isilon Storage Division

Rearrange the struct bufobj and struct vnode layouts to reduce
padding. On the amd64 kernel with INVARIANTS turned off, size of the
struct vnode is reduced from 496 to 472 bytes, saving 24 bytes of
memory and KVA per vnode.

Noted and reviewed by: peter
Tested by: pho
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

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

- Import the HEAD csup code which is the basis for the cvsmode work.

Remove the struct thread unuseful argument from bufobj interface.
In particular following functions KPI results modified:
- bufobj_invalbuf()
- bufsync()

and BO_SYNC() "virtual method" of the buffer objects set.
Main consumers of bufobj functions are affected by this change too and,
in particular, functions which changed their KPI are:
- vinvalbuf()
- g_vfs_close()

Due to the KPI breakage, __FreeBSD_version will be bumped in a later
commit.

As a side note, please consider just temporary the 'curthread' argument
passing to VOP_SYNC() (in bufsync()) as it will be axed out ASAP

Reviewed by: kib
Tested by: Giovanni Trematerra <giovanni dot trematerra at gmail dot com>

- Complete part of the unfinished bufobj work by consistently using
BO_LOCK/UNLOCK/MTX when manipulating the bufobj.
- Create a new lock in the bufobj to lock bufobj fields independently.
This leaves the vnode interlock as an 'identity' lock while the bufobj
is an io lock. The bufobj lock is ordered before the vnode interlock
and also before the mnt ilock.
- Exploit this new lock order to simplify softdep_check_suspend().
- A few sync related functions are marked with a new XXX to note that
we may not properly interlock against a non-zero bv_cnt when
attempting to sync all vnodes on a mountlist. I do not believe this
race is important. If I'm wrong this will make these locations easier
to find.

Reviewed by: kib (earlier diff)
Tested by: kris, pho (earlier diff)

- Handle buffer lock waiters count directly in the buffer cache instead
than rely on the lockmgr support [1]:
* bump the waiters only if the interlock is held
* let brelvp() return the waiters count
* rely on brelvp() instead than BUF_LOCKWAITERS() in order to check
for the waiters number
- Remove a namespace pollution introduced recently with lockmgr.h
including lock.h by including lock.h directly in the consumers and
making it mandatory for using lockmgr.
- Modify flags accepted by lockinit():
* introduce LK_NOPROFILE which disables lock profiling for the
specified lockmgr
* introduce LK_QUIET which disables ktr tracing for the specified
lockmgr [2]
* disallow LK_SLEEPFAIL and LK_NOWAIT to be passed there so that it
can only be used on a per-instance basis
- Remove BUF_LOCKWAITERS() and lockwaiters() as they are no longer
used

This patch breaks KPI so __FreBSD_version will be bumped and manpages
updated by further commits. Additively, 'struct buf' changes results in
a disturbed ABI also.

[2] Really, currently there is no ktr tracing in the lockmgr, but it
will be added soon.

[1] Submitted by: kib
Tested by: pho, Andrea Barberio <insomniac at slackware dot it>

Cylinder group bitmaps and blocks containing inode for a snapshot
file are after snaplock, while other ffs device buffers are before
snaplock in global lock order. By itself, this could cause deadlock
when bdwrite() tries to flush dirty buffers on snapshotted ffs. If,
during the flush, COW activity for snapshot needs to allocate block
and ffs_alloccg() selects the cylinder group that is being written
by bdwrite(), then kernel would panic due to recursive buffer lock
acquision.

Avoid dealing with buffers in bdwrite() that are from other side of
snaplock divisor in the lock order then the buffer being written. Add
new BOP, bop_bdwrite(), to do dirty buffer flushing for same vnode in
the bdwrite(). Default implementation, bufbdflush(), refactors the code
from bdwrite(). For ffs device buffers, specialized implementation is
used.

Reviewed by: tegge, jeff, Russell Cattelan (cattelan xfs org, xfs changes)
Tested by: Peter Holm
X-MFC after: 3 weeks (if ever: it changes ABI)

Fix a spelling error in a comment.

Found with: mckusick's code walkthrough DVDs

- Add a BO_NEEDSGIANT flag to the bufobj. This flag forces all child
buffers to go on the buf daemon's DIRTYGIANT queue.
- Set BO_NEEDSGIANT on ffs's devvp since the ffs_copyonwrite handler
runs in the context of the buf daemon and may require Giant.

Fix a serious deadlock with the NFS client. Given a large enough
atomic write request, it can fill the buffer cache with the entirety
of that write in order to handle retries. However, it never drops
the vnode lock, or else it wouldn't be atomic, so it ends up waiting
indefinitely for more buf memory that cannot be gotten as it has it
all, and it waits in an uncancellable state.

To fix this, hibufspace is exported and scaled to a reasonable
fraction. This is used as the limit of how much of an atomic write
request by the NFS client will be handled asynchronously. If the
request is larger than this, it will be turned into a synchronous
request which won't deadlock the system. It's possible this value is
far off from what is required by some, so it shall be tunable as soon
as mount_nfs(8) learns of the new field.

The slowdown between an asynchronous and a synchronous write on NFS
appears to be on the order of 2x-4x.

General nod by: gad
MFC after: 2 weeks
More testing: wes
PR: kern/79208

- Add bufobj_wrefl() to add a write ref to a bufobj that is already locked.

Try to unbreak the vnode locking around vop_reclaim() (based mostly on
patch from kan@).

Pull bufobj_invalbuf() out of vinvalbuf() and make g_vfs call it on
close. This is not yet a generally safe function, but for this very
specific use it is safe. This solves the problem with buffers not
being flushed by unmount or after failed mount attempts.

Add BO_SYNC() and add a default which uses the secret vnode pointer
and VOP_FSYNC() for now.

Wrap the bufobj operations in macros: BO_STRATEGY() and BO_WRITE()

Give the bufobj a private __bo_vnode for now to keep the syncer floating [1]
At some point later the syncer will unlearn about vnodes and the filesystems
method called by the syncer will know enough about what's in bo_private to
do the right thing.

[1] Ok, I know, but I couldn't resist the pun.

Move the syncer linkage from vnode to bufobj.

This is not quite a perfect separation: the syncer still think it knows
that everything is a vnode.

Put the I/O block size in bufobj->bo_bsize.

We keep si_bsize_phys around for now as that is the simplest way to pull
the number out of disk device drivers in devfs_open(). The correct solution
would be to do an ioctl(DIOCGSECTORSIZE), but the point is probably mooth
when filesystems sit on GEOM, so don't bother for now.

Align comment

Collapse vnode->v_object and buf->b_object into bufobj->bo_object.

Move the buffer method vector (buf->b_op) to the bufobj.

Extend it with a strategy method.

Add bufstrategy() which do the usual VOP_SPECSTRATEGY/VOP_STRATEGY
song and dance.

Rename ibwrite to bufwrite().

Move the two NFS buf_ops to more sensible places, add bufstrategy
to them.

Add inlines for bwrite() and bstrategy() which calls through
buf->b_bufobj->b_ops->b_{write,strategy}().

Replace almost all VOP_STRATEGY()/VOP_SPECSTRATEGY() calls with bstrategy().

Move the VI_BWAIT flag into no bo_flag element of bufobj and call it BO_WWAIT

Add bufobj_wref(), bufobj_wdrop() and bufobj_wwait() to handle the write
count on a bufobj. Bufobj_wdrop() replaces vwakeup().

Use these functions all relevant places except in ffs_softdep.c where
the use if interlocked_sleep() makes this impossible.

Rename b_vnbufs to b_bobufs now that we touch all the relevant files anyway.

Add BO_* macros parallel to VI_* macros for manipulating the bo_mtx.

Initialize the bo_mtx when we allocate a vnode i getnewvnode() For
now we point to the vnodes interlock mutex, that retains the exact
same locking sematics.

Move v_numoutput from vnode to bufobj. Add renaming macro to
postpone code sweep.

Add new function ttyinitmode() which sets our systemwide default
modes on a tty structure. Both the ".init" and the current settings
are initialized allowing the function to be used both at attach and
open time.

The function takes an argument to decide if echoing should be enabled
by default. Echoing should not be enabled for regular physical
serial ports unless they are consoles, in which case they should
be configured by ttyconsolemode() instead.

Use the new function throughout.