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: r264705, r264749
Modify the NFSv4 client create/mkdir RPC so that it acquires
post-create/mkdir directory attributes. This allows the RPC to
name cache the newly created directory and reduces the lookup RPC
count for applications creating a lot of directories.

MFC: r264681
Modify the NFSv4 client open/create RPC so that it acquires
post-open/create directory attributes. This allows the RPC to
name cache the newly created file and reduces the lookup RPC
count by about 10% for software builds.

MFC: r264672
Modify the Lookup RPC for NFSv4 so that it acquires directory
attributes. This allows the client to cache directory names
when they are looked up, reducing the Lookup RPC count by
about 40% for software builds.

MFC r245977:
Be conservative and do not try to consume more bytes than was
requested from the server for the read operation.

MFC: r240289
Add a simple printf() based debug facility to the new nfs client.
Use it for a printf() that can be harmlessly generated for mmap()'d
files. It will be used extensively for the NFSv4.1 client.
Debugging printf()s are enabled by setting vfs.nfs.debuglevel to
a non-zero value. The higher the value, the more debugging printf()s.

MFC 230394,230441,230489,230552,232420:
Close a race in NFS lookup processing that could result in stale name cache
entries on one client when a directory was renamed on another client. The
root cause for the stale entry being trusted is that each per-vnode nfsnode
structure has a single 'n_ctime' timestamp used to validate positive name
cache entries. However, if there are multiple entries for a single vnode,
they all share a single timestamp. To fix this, extend the name cache
to allow filesystems to optionally store a timestamp value in each name
cache entry. The NFS clients now fetch the timestamp associated with
each name cache entry and use that to validate cache hits instead of the
timestamps previously stored in the nfsnode. Another part of the fix is
that the NFS clients now use timestamps from the post-op attributes of
RPCs when adding name cache entries rather than pulling the timestamps out
of the file's attribute cache. The latter is subject to races with other
lookups updating the attribute cache concurrently.

MFC: r229802
opt_inet6.h was missing from some files in the new NFS subsystem.
The effect of this was, for clients mounted via inet6 addresses,
that the DRC cache would never have a hit in the server. It also
broke NFSv4 callbacks when an inet6 address was the only one available
in the client. This patch fixes the above, plus deletes opt_inet6.h
from a couple of files it is not needed for.

MFC: r228827
During investigation of an NFSv4 client crash reported by glebius@,
jhb@ spotted that nfscl_getstateid() might modify credentials when
called from nfsrpc_read() for the case where p != NULL, whereas
nfsrpc_read() only did a crdup() to get new credentials for p == NULL.
This bug was introduced by r195510, since pre-r195510 nfscl_getstateid()
only modified credentials for the p == NULL case. This patch modifies
nfsrpc_read()/nfsrpc_write() so that they do crdup() for the p != NULL case.
It is conceivable that this bug caused the crash reported by glebius@, but
that will not be determined for some time, since the crash occurred after
about 1month of operation.

MFC: r227760
Add two arguments to the nfsrpc_rellockown() function in the NFSv4
client. This does not change the client's behaviour, but prepares
the code so that nfsrpc_rellockown() can be called elsewhere in a
future commit.

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

Approved by: re (implicit)

Modify the new NFSv4 client so that it appends a file handle
to the lock_owner4 string that goes on the wire. Also, add
code to do a ReleaseLockOwner Op on the lock_owner4 string
before a Close. Apparently not all NFSv4 servers handle multiple
instances of the same lock_owner4 string, at least not in a
compatible way. This patch avoids having multiple instances,
except for one unusual case, which will be fixed by a future commit.
Found at the recent NFSv4 interoperability Bakeathon.

Tested by: tdh at excfb.com
MFC after: 2 weeks

Fix the new NFSv4 client so that it doesn't fill the cached
mode attribute in as 0 when doing writes. The change adds
the Mode attribute plus the others except Owner and Owner_group
to the list requested by the NFSv4 Write Operation. This fixed
a problem where an executable file built by "cc" would get mode
0111 instead of 0755 for some NFSv4 servers.
Found at the recent NFSv4 interoperability Bakeathon.

Tested by: tdh at excfb.com
MFC after: 2 weeks

The new NFSv4 client was erroneously using "p" instead of
"p_leader" for the "id" for POSIX byte range locking. I think
this would only have affected processes created by rfork(2)
with the RFTHREAD flag specified. This patch fixes that by
passing the "id" down through the various functions from
nfs_advlock().

MFC after: 2 weeks

Fix the new NFS client so that it correctly sets the "must_commit"
argument for a write RPC when it succeeds for the first one and
fails for a subsequent RPC within the same call to the function.
This makes it compatible with the old NFS client for this case.

MFC after: 2 weeks

Modify the offset + size checks for read and write in the
experimental NFS client to take care of overflows. Thanks
go to dillon at apollo.backplane.com for providing the
snippet of code that does this.

MFC after: 2 weeks

Fix up handling of the nfsmount structure in read and write
within the experimental NFS client. Mostly add mutex locking
and use the same rsize, wsize during the operation by keeping
a local copy of it. This is another change that brings it
closer to the regular NFS client.

MFC after: 2 weeks

Revert r220761 since, as kib@ pointed out, the case of
adding the check to nfsrpc_close() isn't useful. Also,
the check in nfscl_getcl() must be more involved, since
it needs to check before and after the acquisition of
the refcnt on nfsc_lock, while the mutex that protects
the client state data is held.

Add checks for MNTK_UNMOUNTF at the beginning of three
functions, so that threads don't get stuck in them during
a forced dismount. nfs_sync/VFS_SYNC() needs this, since it is
called by dounmount() before VFS_UNMOUNT(). The nfscl_nget()
case makes sure that a thread doing an VOP_OPEN() or
VOP_ADVLOCK() call doesn't get blocked before attempting
the RPC. Attempting RPCs don't block, since they all
fail once a forced dismount is in progress.
The third one at the beginning of nfsrpc_close()
is done so threads don't get blocked while doing VOP_INACTIVE()
as the vnodes are cleared out.
With these three changes plus a change to the umount(1)
command so that it doesn't do "sync()" for the forced case
seem to make forced dismounts work for the experimental NFS
client.

MFC after: 2 weeks

Fix readdirplus in the experimental NFS client so that it
skips over ".." to avoid a LOR race with nfs_lookup(). This
fix is analagous to r138256 in the regular NFS client.

MFC after: 2 weeks

Add a lktype flags argument to nfscl_nget() and ncl_nget() in the
experimental NFS client so that its nfs_lookup() function can use
cn_lkflags in a manner analagous to the regular NFS client.

MFC after: 2 weeks

Fix the experimental NFSv4 server so that it uses VOP_PATHCONF()
to determine if a file system supports NFSv4 ACLs. Since
VOP_PATHCONF() must be called with a locked vnode, the function
is called before nfsvno_fillattr() and the result is passed in
as an extra argument.

MFC after: 2 weeks

Modify the experimental NFSv4 server so that it handles
crossing of server mount points properly. The functions
nfsvno_fillattr() and nfsv4_fillattr() were modified to
take the extra arguments that are the mount point, a flag
to indicate that it is a file system root and the mounted
on fileno. The mount point argument needs to be busy when
nfsvno_fillattr() is called, since the vp argument is not
locked.

Reviewed by: kib
MFC after: 2 weeks

This patch fixes the Experimental NFS client to properly deal with 32 bit or 64
bit fileid's in NFSv2 and NFSv3. Without this fix, invalid casting (and sign
extension) was creating problems for any fileid greater than 2^31.

We discovered this because we have test clusters with more than 2 billion
allocated files and 64-bit ino_t's (and friend structures).

Reviewed by: rmacklem
Approved by: zml (mentor)
MFC after: 2 weeks

Store the full timestamp when caching timestamps of files and
directories for purposes of validating name cache entries. This
closes races where two updates to a file or directory within the same
second could result in stale entries in the name cache. While here,
remove the 'n_expiry' field as it is no longer used.

Reviewed by: rmacklem
MFC after: 1 week

For the experimental NFSv4 client, make sure that attributes that
predate the issue of a delegation are not cached once the delegation
is held. This is necessary, since cached attributes remain valid
while the delegation is held.

MFC after: 2 weeks

In NFS clients, instead of inconsistently using #ifdef
DIAGNOSTIC and #ifndef DIAGNOSTIC for debug assertions, prefer
KASSERT(). Also change one #ifdef DIAGNOSTIC in the new nfs server.

Submitted by: Mikolaj Golub <to.my.trociny gmail com>
MFC after: 2 weeks

Delete a diagnostic statement that is no longer useful from
the experimental NFS client.

MFC after: 1 week

An NFSv4 server will reply NFSERR_GRACE for non-recovery RPCs
during the grace period after startup. This grace period must
be at least the lease duration, which is typically 1-2 minutes.
It seems prudent for the experimental NFS client to wait a few
seconds before retrying such an RPC, so that the server isn't
flooded with non-recovery RPCs during recovery. This patch adds
an argument to nfs_catnap() to implement a 5 second delay
for this case.

MFC after: 1 week

When the experimental NFS client is handling an NFSv4 server reboot
with delegations enabled, the recovery could fail if the renew
thread is trying to return a delegation, since it will not do the
recovery. This patch fixes the above by having nfscl_recalldeleg()
fail with the I/O operations returning EIO, so that they will be
attempted later. Most of the patch consists of adding an argument
to various functions to indicate the delegation recall case where
this needs to be done.

MFC after: 1 week

The experimental NFS client was not filling in recovery credentials
for opens done locally in the client when a delegation for the file
was held. This could cause the client to crash in crsetgroups() when
recovering from a server crash/reboot. This patch fills in the
recovery credentials for this case, in order to avoid the client crash.
Also, add KASSERT()s to the credential copy functions, to catch any
other cases where the credentials aren't filled in correctly.

MFC after: 1 week

Fix the experimental NFS client so that it can create Unix
domain sockets on an NFSv4 mount point. It was generating
incorrect XDR in the request for this case.

Tested by: infofarmer
MFC after: 2 weeks

Remove unneeded ifdefs.

Reviewed by: rmacklem

When vfs.newnfs.callback_addr is set to an IPv4 address, the
experimental NFSv4 client might try and use it as an IPv6 address,
breaking callbacks. The fix simply initializes the isinet6 variable
for this case.

Approved by: re (kensmith), kib (mentor)

Since the nfscl_getclose() function both decremented open counts and,
optionally, created a separate list of NFSv4 opens to be closed, it
was possible for the associated OpenOwner to be free'd before the Open
was closed. The problem was that the Open was taken off the OpenOwner
list before the Close RPC was done and OpenOwners can be free'd once the
list is empty. This patch separates out the case of doing the Close RPC
into a separate function called nfscl_doclose() and simplifies nfsrpc_doclose()
so that it closes a single open instead of a list of them. This avoids
removing the Open from the OpenOwner list before doing the Close RPC.

Approved by: re (kensmith), kib (mentor)

Change the experimental NFSv4 client so that it does not do
the NFSv4 Close operations until ncl_inactive(). This is
necessary so that the Open StateIDs are available for doing
I/O on mmap'd files after VOP_CLOSE(). I also changed some
indentation for the nfscl_getclose() function.

Approved by: kib (mentor)

Add the experimental nfs subtree to the kernel, that includes
support for NFSv4 as well as NFSv2 and 3.
It lives in 3 subdirs under sys/fs:
nfs - functions that are common to the client and server
nfsclient - a mutation of sys/nfsclient that call generic functions
to do RPCs and handle state. As such, it retains the
buffer cache handling characteristics and vnode semantics that
are found in sys/nfsclient, for the most part.
nfsserver - the server. It includes a DRC designed specifically for
NFSv4, that is used instead of the generic DRC in sys/rpc.
The build glue will be checked in later, so at this point, it
consists of 3 new subdirs that should not affect kernel building.

Approved by: kib (mentor)