General cleanup, for diff reduction with NetBSD and future use by FAT
support in makefs.
Submitted by: Siva Mahadevan <smahadevan@freebsdfoundation.org>
Obtained from: NetBSD
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D10821
A long long time ago the register keyword told the compiler to store
the corresponding variable in a CPU register, but it is not relevant
for any compiler used in the FreeBSD world today.
ANSIfy related prototypes while here.
Reviewed by: cem, jhb
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D10193
Extended attributes and their particular implementation in linux are
different from FreeBSD so in this case we have started diverging from
the UFS EA implementation, which would be the natural reference.
Depending on future progress implementing ACLs this approach may change
but for now bring to the tree an implementation that is consistent and
can be tested.
Submitted by: Fedor Uporov
Differential Revision: https://reviews.freebsd.org/D10460
The code specified the length of a layout as INT64_MAX instead of
UINT64_MAX. This could result in getting a layout for less than the
full file for extremely large files. Although having little practical
effect, this patch corrects this in the code.
Detected during recent testing of the pNFS server.
MFC after: 2 weeks
The nfsv4_seqsession() call returns NFSERR_REPLYFROMCACHE when it has a
reply in the session, due to a requestor retry. The code erroneously
assumed a return of 0 for this case. This patch fixes this and adds
a KASSERT(). This would be an extremely rare occurrence. It was found
during code inspection during the pNFS server development.
MFC after: 2 weeks
The NFSv4 RFCs give a server the option of allowing the use of an open
stateid for write access to be used for a Read operation.
This patch enables this by default and adds a sysctl to disable it,
for anyone who does not want this capability.
Allowing this is particularily useful for a pNFS Data Server (DS), since
they are not permitted to allow the use of special stateids.
Discovered during recent testing of the pNFS server under development.
MFC after: 2 weeks
An NFSv4 server has the option of allowing a Read to be done using a Write
Open. If this is not allowed, the server will return NFSERR_OPENMODE.
This patch attempts the read with a write open and then disables this
if the server replies NFSERR_OPENMODE.
This change will avoid some uses of the special stateids. This will be
useful for pNFS/DS Reads, since they cannot use special stateids.
It will also be useful for any NFSv4 server that does not support reading
via the special stateids. It has been tested against both types of NFSv4 server.
MFC after: 2 weeks
The NFSv4.1/pNFS client does not use/need a backchannel for the Data Server (DS)
sessions, so the flag should only be set for MetaData Server (MDS) sessions.
This patch should have been a part of r317275.
MFC after: 2 weeks
The "return layout on close" case in the pNFS client was badly broken.
Fortunately, extant pNFS servers that I have tested against do not
do this. This patch fixes it. It also changes the way the layout stateid.seqid
is set for LayoutReturn. I think this change is correct w.r.t. the RFC,
but I am not 100% sure.
This was found during recent testing of the pNFS server under development.
MFC after: 2 weeks
The NFSv4.1/pNFS client wasn't doing a newnfs_disconnect() call for the
connection to the Data Server (DS) under some circumstances. The main
effect of this was a leak of malloc'd structures in the krpc. This patch
adds the newnfs_disconnect() calls to fix this.
Detected during recent testing against the pNFS server under development.
MFC after: 2 weeks
The NFSv4 Setattr operation always has reply data even when it fails,
so don't set the ND_NOMOREDATA for it. This would only affect unusual
cases where Setattr fails and the RPC code wants to parse the rest of
the compound. Detected during recent development related to the pNFS server.
MFC after: 2 weeks
An NFSv4.1 client connection to a Data Server (DS) should not have a
backchannel. This patch fixes the NFSv4.1/pNFS client to not do a backchannel
for this case.
Found during recent testing with the pNFS server under development.
MFC after: 2 weeks
Implement FUSE open flag FOPEN_KEEP_CACHE. Without this flag, cached file
contents should be invalidated on open. Apparently, fusefs-encfs relies
upon this behavior.
PR: 218636
Submitted by: Ben RUBSON <ben.rubson at gmail.com>
The nfscl_mtofh() function didn't check for failed operations and, as such,
would have returned EBADRPC for these cases, due to parsing failure.
This patch adds checks, so that it returns with ND_NOMOREDATA set.
This is needed for future use in the pNFS server and acts as a safety
belt in the meantime.
MFC after: 2 weeks
The default uid/gid for NFSv4 are set by the nfsuserd(8) daemon.
However, they were 0 until the nfsuserd(8) was run. Since it is
possible to use NFSv4 without running the nfsuserd(8) daemon, set them
to nobody/nogroup initially.
Without this patch, the values would be set by the nfsuserd(8) daemon
and left changed even if the nfsuserd(8) daemon was killed. The default
values of 0 meant that setting a group to "wheel" would fail even when
done by root.
It also adds a definition of GID_NOGROUP to sys/conf.h.
Discussed on: freebsd-current@
MFC after: 2 weeks
The default uid/gid for NFSv4 are set by the nfsuserd(8) daemon.
However, they were 0 until the nfsuserd(8) was run. Since it is
possible to use NFSv4 without running the nfsuserd(8) daemon, set them
to nobody/nogroup initially.
Without this patch, the values would be set by the nfsuserd(8) daemon
and left changed even if the nfsuserd(8) daemon was killed. Also, the default
values of 0 meant that setting a group to "wheel" would fail even when
done by root and this patch fixes this issue.
MFC after: 2 weeks
The FreeBSD NFSv4 server did not set the attribute bit for TimeAccess in
the reply to an Open with exclusive_create, as required by the RFCs.
(This is required since the FreeBSD NFS server stores the create_verifier
in the va_atime attribute.)
As such, the Linux NFSv4 client did not set the TimeAccess (atime) in
the Setattr done in an RPC after the one with the Open/exclusive_create.
This patch fixes the server to set the TimeAccess bit in the reply.
I believe that storing the create_verifier in an extended attribute for
file systems that support extended attributes might be a good idea,
but I will wait for a discussion of this on the freebsd-fs@ email list
before considering committing a patch to do this.
Reported by: jim@ks.uiuc.edu
Suggested by: dfr
MFC after: 2 weeks
in place. To do per-cpu stats, convert all fields that previously were
maintained in the vmmeters that sit in pcpus to counter(9).
- Since some vmmeter stats may be touched at very early stages of boot,
before we have set up UMA and we can do counter_u64_alloc(), provide an
early counter mechanism:
o Leave one spare uint64_t in struct pcpu, named pc_early_dummy_counter.
o Point counter(9) fields of vmmeter to pcpu[0].pc_early_dummy_counter,
so that at early stages of boot, before counters are allocated we already
point to a counter that can be safely written to.
o For sparc64 that required a whole dummy pcpu[MAXCPU] array.
Further related changes:
- Don't include vmmeter.h into pcpu.h.
- vm.stats.vm.v_swappgsout and vm.stats.vm.v_swappgsin changed to 64-bit,
to match kernel representation.
- struct vmmeter hidden under _KERNEL, and only vmstat(1) is an exclusion.
This is based on benno@'s 4-year old patch:
https://lists.freebsd.org/pipermail/freebsd-arch/2013-July/014471.html
Reviewed by: kib, gallatin, marius, lidl
Differential Revision: https://reviews.freebsd.org/D10156
The "cred" argument of ncl_flush() is unused and it was confusing to have
the code passing in NULL for this argument in some cases. This patch deletes
this argument.
There is no semantic change because of this patch.
MFC after: 2 weeks
Some NFSv4.1 servers such as AmazonEFS can only support a small fixed number
of open_owner4s. This patch adds a mount option called "oneopenown" that
can be used for NFSv4.1 mounts to make the client do all Opens with the
same open_owner4 string. This option can only be used with NFSv4.1 and
may not work correctly when Delegations are is use.
Reported by: cperciva
Tested by: cperciva
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D8988
A function called svcpool_close() was added to the server side krpc by
r313735, so that a pool could be closed without destroying the data structures.
This little patch adds a call to it for the callback pool (svcpool_nfscbd),
so that the nfscbd daemon can be killed/restarted and continue to work
correctly.
MFC after: 2 weeks
When an mmap'd text file is written and then executed immediately
afterwards, it was possible that the modify time would change after the
text file was executing, resulting in the process executing the file
being killed. This was usually only observed when the file system's
times were set to higher resolution, but could have occurred for any
time resolution.
This was reported on a recent email list discussion.
This patch adds a VOP_SET_TEXT() to the NFS client which flushed all
dirty pages to the NFS server and then makes sure that n_mtime is up
to date to avoid this from occurring.
Thanks go to kib@ and pho@ for their help with developing this patch.
Tested by: pho
Reviewed by: kib
MFC after: 2 weeks
If the ExchangeID/CreateSession operations done by an NFSv4.1 client
after the server crashes/reboots fails, it is possible that some process/thread
is waiting for an open_owner lock. If the client state is free'd, this
can cause a crash.
This would not normally happen, but has been observed on a mount of the
AmazonEFS service.
Reported by: cperciva
Tested by: cperciva
PR: 216086
MFC after: 2 weeks
during recovery.
If the NFSv4.1 client gets a NFSv4.1 NFSERR_BADSESSION reply to an Open/Lock
operation while recovering from the server crash/reboot, allow the opens
to be retained for a subsequent recovery attempt. Since NFSv4.1 servers
should only reply NFSERR_BADSESSION after a crash/reboot that has lost
state, this case should almost never happen.
However, for the AmazonEFS file service, this has been observed when
the client does a fresh TCP connection for RPCs.
Reported by: cperciva
Tested by: cperciva
PR: 216088
MFC after: 2 weeks
Instead, issue a diagnostic and return appropriate error if
ncl_flush() was unable to clean buffer queue after the specified
number or retries.
Reviewed by: rmacklem
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
The AmazonEFS NFSv4.1 server does not support the FILES_FREE and FILES_TOTAL
attributes. As such, an NFSv4.1 mount to the server would return garbage
for these values. This patch initializes the fields of the nfsstatfs structure,
so that "df" and friends will at least return consistent bogus values.
This patch should have effect when mounting other NFSv4.1 servers.
Reported by: cperciva
MFC after: 2 weeks
This patch gives a requestor of the exclusive lock on the client state
in the NFSv4 client priority over shared lock requestors. This avoids
the server crash recovery thread being starved out by other threads doing
RPCs.
Tested by: cperciva
PR: 216087
MFC after: 2 weeks
When the NFSv4 client Commit operation encountered a stale write verifier,
it erroneously mapped that to EIO. This could have caused recently written
data to be lost when a server crashes/reboots between an UNSTABLE write
and the subsequent commit. This patch fixes this.
The bug was only for the NFSv4 client and did not affect NFSv3.
Tested by: cperciva
PR: 215887
MFC after: 2 weeks
For the ReclaimComplete operation, the RPC layer should not loop on
NFSERR_BADSESSION. If it does, the recovery thread (nfscl) can get stuck
looping and will not do a recovery.
This patch fixes it so it does not loop. This bug only affects NFSv4.1 and
only when a server reboots.
Tested by: cperciva
PR: 215886
MFC after: 2 weeks
If an operation that preceeds a Setattr in an NFSv4 compound fails,
there is no bitmap of attributes to parse. Without this patch, the
parsing would fail and return EBADRPC instead of the correct failure
error. This could break recovery from a server crash/reboot.
Tested by: cperciva
PR: 215883
MFC after: 2 weeks
Based on the change in r242386, it seems clear that scred was intended to
be released in all paths at exit.
No functional change. This line's indent was just the result of a bad copy
paste from the previous free() in an early exit path.
Reported by: PVS-Studio
Sponsored by: Dell EMC Isilon
Write out the dirty pages using VOP_WRITE() instead of directly
calling ncl_writerpc(). The state of the buffers now reflects the
write, fixing some hard to diagnose consistency and write order
issues. The change also allowed to remove remapping of paged out
pages into kernel space and related allocation of the phys buffer.
Reviewed by: markj, rmacklem
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D10241
ncl_vinvalbuf() might need to upgrade vnode lock, allowing the vnode
to be reclaimed by other thread. Handle the situation, indicated by
the returned error zero and VI_DOOMED iflag set, converting it into
EBADF. Handle all calls, even where the vnode is exclusively locked
right now.
Reviewed by: markj, rmacklem
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
X-Differential revision: https://reviews.freebsd.org/D10241
This interface has no in-tree consumers and has been more or less
non-functional for several releases.
Remove manpage note that the procfs special file 'mem' is grouped to
kmem. This hasn't been true since r81107.
Remove procfs' README file. It is an out of date duplication of the manpage
(quoth the README: "since the bsd kernel is single-processor...").
Reviewed by: vangyzen, bcr (manpage)
Approved by: des (procfs maintainer), vangyzen (mentor)
Differential Revision: https://reviews.freebsd.org/D9802
Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.
Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96
Thread might create a condition for delayed SU cleanup, which creates
a reference to the mount point in td_su, but exit without returning
through userret(), e.g. when terminating due to single-threading or
process exit. In this case, td_su reference is not dropped and mount
point cannot be freed.
Handle the situation by clearing td_su also in the thread destructor
and in exit1(). softdep_ast_cleanup() has to receive the thread as
argument, since e.g. thread destructor is executed in different
context.
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Right now the noexec mount option disallows image activators to try
execve the files on the mount point. Also, after r127187, noexec
also limits max_prot map entries permissions for mappings of files
from such mounts, but not the actual mapping permissions.
As result, the API behaviour is inconsistent. The files from noexec
mount can be mapped with PROT_EXEC, but if mprotect(2) drops execution
permission, it cannot be re-enabled later. Make this consistent
logically and aligned with behaviour of other systems, by disallowing
PROT_EXEC for mmap(2).
Note that this change only ensures aligned results from mmap(2) and
mprotect(2), it does not prevent actual code execution from files
coming from noexec mount. Such files can always be read into
anonymous executable memory and executed from there.
Reported by: shamaz.mazum@gmail.com
PR: 217062
Reviewed by: alc
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
inet_ntoa() cannot be used safely in a multithreaded environment
because it uses a static local buffer. Instead, use inet_ntoa_r()
with a buffer on the caller's stack.
Suggested by: glebius, emaste
Reviewed by: gnn
MFC after: 2 weeks
Sponsored by: Dell EMC
Differential Revision: https://reviews.freebsd.org/D9625
Right now this is not critical, but will be after planned increase of
MNAMELEN from 88 to 1k.
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
It's not a proper fix, but should be better than what we have now.
Since it got broken some six months ago it results in an incredibly
annoying and trivially reproducible panic every time eg an USB disk
gets disconnected.
MFC after: 2 weeks
Sponsored by: DARPA, AFRL
This patch adds a new function to the server krpc called
svcpool_close(). It is similar to svcpool_destroy(), but does not free
the data structures, so that the pool can be used again.
This function is then used instead of svcpool_destroy(),
svcpool_create() when the nfsd threads are killed.
PR: 204340
Reported by: Panzura
Approved by: rmacklem
Obtained from: rmacklem
MFC after: 1 week
The option "nonc" disables using of namecache for the created mount,
by default namecache is used. The rationale for the option is that
namecache duplicates the information which is already kept in memory
by tmpfs. Since it believed that namecache scales better than tmpfs,
or will scale better, do not enable the option by default. On the
other hand, smaller machines may benefit from lesser namecache
pressure.
Discussed with: mjg
Tested by: pho (as part of larger patch)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
For directories, node->tn_spec.tn_dir.tn_parent pointer to the parent
is used. For non-directories, the implementation is naive, all
directory nodes are scanned to find a dirent linking the specified
node. This can be significantly improved by maintaining tn_parent for
all nodes, later.
Tested by: pho (as part of larger patch)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
On dotdot lookup and fhtovp operations, it is possible for the file
represented by tmpfs node to be removed after the thread calculated
the pointer. In this case, tmpfs_alloc_vp() accesses freed memory.
Introduce the reference count on the nodes. The allnodes list from
tmpfs mount owns 1 reference, and threads performing unlocked
operations on the node, add one transient reference. Similarly, since
struct tmpfs_mount maintains the list where nodes are enlisted,
refcount it by one reference from struct mount and one reference from
each node on the list. Both nodes and tmpfs_mounts are removed when
refcount goes to zero.
Note that this means that nodes and tmpfs_mounts might survive some
time after the node is deleted or tmpfs_unmount() finished. The
tmpfs_alloc_vp() in these cases returns error either due to node
removal (tn_nlinks == 0) or because of insmntque1(9) error.
Tested by: pho (as part of larger patch)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Remove TMPFS_ASSERT_ELOCKED(). Its claims are already stated by other
asserts nearby and by VFS guarantees.
Change TMPFS_ASSERT_LOCKED() and one inlined place to use
ASSERT_VOP_(E)LOCKED() instead of hand-rolled imprecise asserts.
Tested by: pho (as part of the larger patch)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Edit comments which explain no longer relevant details, and add
locking annotations to the struct tmpfs_node members.
Tested by: pho (as part of the larger patch)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
If some process' nodes were accessed using procfs and the process
cannot exit properly at the time modunload event is reported to the
pseudofs-backed filesystem, the assertion in pfs_vncache_unload() is
triggered. Assertion is correct, the cache should be cleaned.
Approved by: des (pseudofs maintainer)
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Inums in cd9660 refer to byte offsets on the media. DVD and BD media
can have entries above 4GB, especially with multi-session images.
PR: 190655
Reported by: Thomas Schmitt <scdbackup at gmx.net>
If tmpfs vnode is only shared locked, tn_status field still needs
updates to note the access time modification. Use the same locking
scheme as for UFS, protect tn_status with the node interlock + shared
vnode lock.
Fix nearby style.
Noted and reviewed by: mjg
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Right now size of the structure is 472 bytes on amd64, which is
already large and stack allocations are indesirable. With the ino64
work, MNAMELEN is increased to 1024, which will make it impossible to have
struct statfs on the stack.
Extracted from: ino64 work by gleb
Discussed with: mckusick
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
For most NFSv4.1 servers, a NFS4ERR_BAD_SESSION error is a rare failure
that indicates that the server has lost session/open/lock state.
However, recent testing by cperciva@ against the AmazonEFS server found
several problems with client recovery from this due to it generating this
failure frequently.
Briefly, the problems fixed are:
- If all session slots were in use at the time of the failure, some processes
would continue to loop waiting for a slot on the old session forever.
- If an RPC that doesn't use open/lock state failed with NFS4ERR_BAD_SESSION,
it would fail the RPC/syscall instead of initiating recovery and then
looping to retry the RPC.
- If a successful reply to an RPC for an old session wasn't processed
until after a new session was created for a NFS4ERR_BAD_SESSION error,
it would erroneously update the new session and corrupt it.
- The use of the first element of the session list in the nfs mount
structure (which is always the current metadata session) was slightly
racey. With changes for the above problems it became more racey, so all
uses of this head pointer was wrapped with a NFSLOCKMNT()/NFSUNLOCKMNT().
- Although the kernel malloc() usually allocates more bytes than requested
and, as such, this wouldn't have caused problems, the allocation of a
session structure was 1 byte smaller than it should have been.
(Null termination byte for the string not included in byte count.)
There are probably still problems with a pNFS data server that fails
with NFS4ERR_BAD_SESSION, but I have no server that does this to test
against (the AmazonEFS server doesn't do pNFS), so I can't fix these yet.
Although this patch is fairly large, it should only affect the handling
of NFS4ERR_BAD_SESSION error replies from an NFSv4.1 server.
Thanks go to cperciva@ for the extension testing he did to help isolate/fix
these problems.
Reported by: cperciva
Tested by: cperciva
MFC after: 3 months
Differential Revision: https://reviews.freebsd.org/D8745
truncation, immediately queue the page for asynchronous laundering rather
than making the page pass through inactive queue first.
Reviewed by: kib, markj
The NFSv4.1 server failed to update the nfs-stablerestart file for
a client when the client was issued its first Open. As such, recovery
of Opens after a server reboot failed with NFSERR_NOGRACE.
This patch fixes this.
It also changes the code so that it malloc()'s the 1024 byte array
instead of allocating it on the kernel stack for both NFSv4.0 and NFSv4.1.
Note that this bug only affected NFSv4.1 and only when clients attempted
to reclaim Opens after a server reboot.
MFC after: 2 weeks
the vnode is inactivated. This contradicts with the nullfs caching
which keeps upper vnode around, as consequence keeping the use
reference to lower vnode.
Add a filesystem flag to request nullfs to not cache when mounted over
that filesystem, and set the flag for nfs v4 mounts.
Reported by: asomers
Reviewed by: rmacklem
Tested by: asomers, rmacklem
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
The "-z" option on nfsstats was erroneously zeroing out the counts
of NFSv4 state structures. These counts will normally go back down
to zero as state is released. When zeroed out by "-z", these counts
can go negative. This patch fixes this problem.
MFC after: 2 weeks
The swap pager enqueues laundered pages near the head of the inactive queue
to avoid another trip through LRU before reclamation. This change adds
support for this behaviour to the vnode pager and makes use of it in UFS and
ext2fs. Some ioflag handling is consolidated into a common subroutine so
that this support can be easily extended to other filesystems which make use
of the buffer cache. No changes are needed for ZFS since its putpages
routine always undirties the pages before returning, and the laundry
thread requeues the pages appropriately in this case.
Reviewed by: alc, kib
Differential Revision: https://reviews.freebsd.org/D8589
longer used. More precisely, they are always zero because the code that
decremented and incremented them no longer exists.
Bump __FreeBSD_version to mark this change.
Reviewed by: kib, markj
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D8583
See r294954 for the bread(9) change and r297401 for similar cd9660 fix.
Reported and tested by: Joshua Kinard <kumba@gentoo.org>
PR: 214705
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
The pager, due to its construction, implements clustering for the
page-ins. In particular, buildworld load demonstrates reduction of
the READ RPCs from 39k down to 24k. No change in real or CPU time was
observed.
Discussed with, and measured by: bde
No objections from: rmacklem
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Rather than printing a warning for every time we receive a fileid > 2^32
from the NFS server, count warnings and print at most one of each warning
type per minute, e.g.,
Nov 15 05:17:34 ip-172-30-1-221 kernel: NFSv4 fileid > 32bits (24730 occurrences)
Nov 15 05:17:56 ip-172-30-1-221 kernel: NFSv4 mounted on fileid > 32bits (178 occurrences)
Nov 15 05:18:53 ip-172-30-1-221 kernel: NFSv4 fileid > 32bits (7582 occurrences)
Nov 15 05:18:58 ip-172-30-1-221 kernel: NFSv4 mounted on fileid > 32bits (23 occurrences)
A buildworld with an NFS mounted /usr/obj can otherwise result in
hundreds of thousands of lines being printed, which seems unnecessarily
verbose.
When ino_t becomes a 64-bit type, these printfs will no longer be needed
(and the problems associated with truncating 64-bit fileids to generate
32-bit inode numbers will also go away).
Reviewed by: rmacklem
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D8523
not remove user-space visible fields from vm_cnt or all of the references to
cached pages from comments. Those changes will come later.)
Reviewed by: kib, markj
Tested by: pho
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D8497
