Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

MFC r230249:

Make sure all intermediate variables holding mount flags (mnt_flag)
and that all internal kernel calls passing mount flags are declared
as uint64_t so that flags in the top 32-bits are not lost.

MFC r230250:

There are several bugs/hangs when trying to take a snapshot on a UFS/FFS
filesystem running with journaled soft updates. Until these problems
have been tracked down, return ENOTSUPP when an attempt is made to
take a snapshot on a filesystem running with journaled soft updates.

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Remove the thread argument from the FSD (File-System Dependent) parts of
the VFS. Now all the VFS_* functions and relating parts don't want the
context as long as it always refers to curthread.

In some points, in particular when dealing with VOPs and functions living
in the same namespace (eg. vflush) which still need to be converted,
pass curthread explicitly in order to retain the old behaviour.
Such loose ends will be fixed ASAP.

While here fix a bug: now, UFS_EXTATTR can be compiled alone without the
UFS_EXTATTR_AUTOSTART option.

VFS KPI is heavilly changed by this commit so thirdy parts modules needs
to be recompiled. Bump __FreeBSD_version in order to signal such
situation.

Retire the MALLOC and FREE macros. They are an abomination unto style(9).

MFC after: 3 months

Get rid of qaddr_t.

Requested by: bde

Make pseudofs (and consequently procfs, linprocfs and linsysfs) MPSAFE.

Further pseudofs improvements:

The pfs_info mutex is only needed to lock pi_unrhdr. Everything else
in struct pfs_info is modified only while Giant is held (during
vfs_init() / vfs_uninit()); add assertions to that effect.

Simplify pfs_destroy somewhat.

Remove superfluous arguments from pfs_fileno_{alloc,free}(), and the
assertions which were added in the previous commit to ensure they were
consistent.

Assert that Giant is held while the vnode cache is initialized and
destroyed. Also assert that the cache is empty when it is destroyed.

Rename the vnode cache mutex for consistency.

Fix a long-standing bug in pfs_getattr(): it would uncritically return
the node's pn_fileno as st_ino. This would result in st_ino being 0
if the node had not previously been visited by readdir(), and also in
an incorrect st_ino for process directories and any files contained
therein. Correct this by abstracting the fileno manipulations
previously done in pfs_readdir() into a new function, pfs_fileno(),
which is used by both pfs_getattr() and pfs_readdir().

Add a flag to struct pfs_vdata to mark the vnode as dead (e.g. process-
specific nodes when the process exits)

Move the vnode-cache-walking loop which was duplicated in pfs_exit() and
pfs_disable() into its own function, pfs_purge(), which looks for vnodes
marked as dead and / or belonging to the specified pfs_node and reclaims
them. Note that this loop is still extremely inefficient.

Add a comment in pfs_vncache_alloc() explaining why we have to purge the
vnode from the vnode cache before returning, in case anyone should be
tempted to remove the call to cache_purge().

Move the special handling for pfstype_root nodes into pfs_fileno_alloc()
and pfs_fileno_free() (the root node's fileno must always be 2). This
also fixes a bug where pfs_fileno_free() would reclaim the root node's
fileno, triggering a panic in the unr code, as that fileno was never
allocated from unr to begin with.

When destroying a pfs_node, release its fileno and purge it from the
vnode cache. I wish we could put off the call to pfs_purge() until
after the entire tree had been destroyed, but then we'd have vnodes
referencing freed pfs nodes. This probably doesn't matter while we're
still under Giant, but might become an issue later.

When destroying a pseudofs instance, destroy the tree before tearing
down the fileno allocator.

In pfs_mount(), acquire the mountpoint interlock when required.

MFC after: 3 weeks

Whitespace nits.

Add a pn_destroy field to pfs_node. This field points to a destructor
function which is called from pfs_destroy() before the node is reclaimed.

Modify pfs_create_{dir,file,link}() to accept a pointer to a destructor
function in addition to the usual attr / fill / vis pointers.

This breaks both the programming and binary interfaces between pseudofs
and its consumers. It is believed that there are no pseudofs consumers
outside the source tree, so that the impact of this change is minimal.

Submitted by: Aniruddha Bohra <bohra@cs.rutgers.edu>

Restore the ability to mount procfs and fdescfs filesystems via the
mount(2) system call:

* Add cmount hook to fdescfs and pseudofs (and, by extension, procfs and
linprocfs). This (mostly) restores the ability to mount these
filesystems using the old mount(2) system call (see below for the
rest of the fix).

* Remove not-NULL check for the data argument from the mount(2) entry
point. Per the mount(2) man page, it is up to the individual
filesystem being mounted to verify data. Or, in the case of procfs,
etc. the filesystem is free to ignore the data parameter if it does
not use it. Enforcing data to be not-NULL in the mount(2) system call
entry point prevented passing NULL to filesystems which ignored the
data pointer value. Apparently, passing NULL was common practice
in such cases, as even our own mount_std(8) used to do it in the
pre-nmount(2) world.

All userland programs in the tree were converted to nmount(2) long ago,
but I've found at least one external program which broke due to this
(presumably unintentional) mount(2) API change. One could argue that
external programs should also be converted to nmount(2), but then there
isn't much point in keeping the mount(2) interface for backward
compatibility if it isn't backward compatible.

- Update vfs_root implementations to match the new prototype. None of
these filesystems will support shared locks until they are explicitly
modified to do so. Careful review must be done to ensure that this
is safe for each individual filesystem.

Sponsored by: Isilon Systems, Inc.

Use subr_unit

fbsdidize.

Use vfs_mountedfrom().

Since VFS_STATFS() always calls the filesystem with mp->mnt_stat now, the
vfs_statfs method is now a no-op. Explain this in a comment.

Put a version element in the VFS filesystem configuration structure
and refuse initializing filesystems with a wrong version. This will
aid maintenance activites on the 5-stable branch.

s/vfs_mount/vfs_omount/

s/vfs_nmount/vfs_mount/

Name our filesystems mount function consistently.

Eliminate the namiedata argument to both vfs_mount and vfs_omount.
It was originally there to save stack space. A few places abused
it to get hold of some credentials to pass around. Effectively
it is unused.

Reorganize the root filesystem selection code.

Do a pass over all modules in the kernel and make them return EOPNOTSUPP
for unknown events.

A number of modules return EINVAL in this instance, and I have left
those alone for now and instead taught MOD_QUIESCE to accept this
as "didn't do anything".

Make VFS_ROOT() and vflush() take a thread argument.
This is to allow filesystems to decide based on the passed thread
which vnode to return.
Several filesystems used curthread, they now use the passed thread.

Constify, and add an API function to find a named node in a directory.

Back out M_* changes, per decision of the TRB.

Approved by: trb

Remove M_TRYWAIT/M_WAITOK/M_WAIT. Callers should use 0.
Merge M_NOWAIT/M_DONTWAIT into a single flag M_NOWAIT.

Remove all use of vnode->v_tag, replacing with appropriate substitutes.
v_tag is now const char * and should only be used for debugging.

Additionally:
1. All users of VT_NTS now check vfsconf->vf_type VFCF_NETWORK
2. The user of VT_PROCFS now checks for the new flag VV_PROCDEP, which
is propagated by pseudofs to all child vnodes if the fs sets PFS_PROCDEP.

Suggested by: phk
Reviewed by: bde, rwatson (earlier version)

Gratuitous whitespace cleanup.

Convert the pseudofs framework to nmount (thus procfs and linprocfs).

Reviewed by: des (some time ago), phk

Change callers of mtx_init() to pass in an appropriate lock type name. In
most cases NULL is passed, but in some cases such as network driver locks
(which use the MTX_NETWORK_LOCK macro) and UMA zone locks, a name is used.

Tested on: i386, alpha, sparc64

Update to C99, s/__FUNCTION__/__func__/,
also don't use ANSI string concatenation.

Add support for a last-close handler.
Revert the module version bumps; they're quite pointless as long as the
only pseudofs consumer is linprocfs, which is in the tree.

Reduce the number of #include dependencies by declaring some of the structs
used in pseudofs.h as opaque structs.

Argh! I updated the version number in the MODULE_DEPEND() thingamagook but
not in the actual MODULE_VERSION(). Pass me the pointy hat.

Switch to dynamic rather than static initialization.
This makes it possible (in theory) for nodes to be added and / or removed
from pseudofs filesystems at runtime.

Add missing includes of sys/lock.h.

Only print "XXX (un)registered" message if bootverbose.

Pseudofs take 2:

- Remove hardcoded uid, gid, mode from struct pfs_node; make pfs_getattr()
smart enough to get it right most of the time, and allow for callbacks
to handle the remaining cases. Rework the definition macros to match.

- Add lots of (conditional) debugging output.

- Fix a long-standing bug inherited from procfs: don't pretend to be a
read-only file system. Instead, return EOPNOTSUPP for operations we
truly can't support and allow others to fail silently. In particular,
pfs_lookup() now treats CREATE as LOOKUP. This may need more work.

- In pfs_lookup(), if the parent node is process-dependent, check that
the process in question still exists.

- Implement pfs_open() - its only current function is to check that the
process opening the file can see the process it belongs to.

- Finish adding support for writeable nodes.

- Bump module version number.

- Introduce lots of new bugs.

KSE Milestone 2
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.

Sorry john! (your next MFC will be a doosie!)

Reviewed by: peter@freebsd.org, dillon@freebsd.org

X-MFC after: ha ha ha ha

Add support for process-dependent directories. This means that save for
the lack of a man page, pseudofs is mostly complete now.

Add missing #include of <sys/mutex.h>.

Let pseudofs into the warmth of the FreeBSD CVS repo.

It's not finished yet (I still have to find a way to implement process-
dependent nodes without consuming too much memory, and the permission
system needs tightening up), but it's becoming hard to work on without
a repo (I've accidentally almost nuked it once already), and it works
(except for the lack of process-dependent nodes, that is).

I was supposed to commit this a week ago, but timed out waiting for jkh
to reply to some questions I had. Pass him a spoonful of bad karma :)