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 r226234:

Make unionfs also clear VAPPEND when clearing VWRITE, since VAPPEND
is just a modifier for VWRITE.

MFC: 234867 and 234944

- fixed a vnode lock hang-up issue.
- fixed an incorrect lock status issue.
- fixed an incorrect lock issue of unionfs root vnode removed.
(pointed out by keith)
- fixed an infinity loop issue.
(pointed out by dumbbell)
- changed to do LK_RELEASE expressly when unlocked.
- fixed a unionfs_readdir math issue

Submitted by: ozawa@ongs.co.jp, Matthew Fleming <mfleming@isilon.com>

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

Approved by: re (implicit)

Rework the credential code to support larger values of NGROUPS and
NGROUPS_MAX, eliminate ABI dependencies on them, and raise the to 1024
and 1023 respectively. (Previously they were equal, but under a close
reading of POSIX, NGROUPS_MAX was defined to be too large by 1 since it
is the number of supplemental groups, not total number of groups.)

The bulk of the change consists of converting the struct ucred member
cr_groups from a static array to a pointer. Do the equivalent in
kinfo_proc.

Introduce new interfaces crcopysafe() and crsetgroups() for duplicating
a process credential before modifying it and for setting group lists
respectively. Both interfaces take care for the details of allocating
groups array. crsetgroups() takes care of truncating the group list
to the current maximum (NGROUPS) if necessary. In the future,
crsetgroups() may be responsible for insuring invariants such as sorting
the supplemental groups to allow groupmember() to be implemented as a
binary search.

Because we can not change struct xucred without breaking application
ABIs, we leave it alone and introduce a new XU_NGROUPS value which is
always 16 and is to be used or NGRPS as appropriate for things such as
NFS which need to use no more than 16 groups. When feasible, truncate
the group list rather than generating an error.

Minor changes:
- Reduce the number of hand rolled versions of groupmember().
- Do not assign to both cr_gid and cr_groups[0].
- Modify ipfw to cache ucreds instead of part of their contents since
they are immutable once referenced by more than one entity.

Submitted by: Isilon Systems (initial implementation)
X-MFC after: never
PR: bin/113398 kern/133867

Remove VOP_LEASE and supporting functions. This hasn't been used since
the removal of NQNFS, but was left in in case it was required for NFSv4.
Since our new NFSv4 client and server can't use it for their
requirements, GC the old mechanism, as well as other unused lease-
related code and interfaces.

Due to its impact on kernel programming and binary interfaces, this
change should not be MFC'd.

Proposed by: jeff
Reviewed by: jeff
Discussed with: rmacklem, zach loafman @ isilon

Fixes Unionfs socket issue reported as kern/118346.

PR: 118346
Submitted by: Masanori OZAWA <ozawa@ongs.co.jp>
Discussed at: devsummit Strassburg, EuroBSDCon2008
Discussed with: rwatson, gnn, hrs
MFC after: 2 week

Introduce accmode_t. This is required for NFSv4 ACLs - it will be neccessary
to add more V* constants, and the variables changed by this patch were often
being assigned to mode_t variables, which is 16 bit.

Approved by: rwatson (mentor)

Decontextualize the couplet VOP_GETATTR / VOP_SETATTR as the passed thread
was always curthread and totally unuseful.

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

o Fixed multi thread access issue reported by Alexander V. Chernikov
(admin@su29.net)
fixed: kern/109950

PR: kern/109950
Submitted by: Alexander V. Chernikov (admin@su29.net)
Reviewed by: Masanori OZAWA (ozawa@ongs.co.jp)
MFC after: 1 week

o Fixed rename panic issue

Submitted by: Masanori OZAWA (ozawa@ongs.co.jp)
MFC after: 1 week

Axe the 'thread' argument from VOP_ISLOCKED() and lockstatus() as it is
always curthread.

As KPI gets broken by this patch, manpages and __FreeBSD_version will be
updated by further commits.

Tested by: Andrea Barberio <insomniac at slackware dot it>

VOP_LOCK1() (and so VOP_LOCK()) and VOP_UNLOCK() are only used in
conjuction with 'thread' argument passing which is always curthread.
Remove the unuseful extra-argument and pass explicitly curthread to lower
layer functions, when necessary.

KPI results broken by this change, which should affect several ports, so
version bumping and manpage update will be further committed.

Tested by: kris, pho, Diego Sardina <siarodx at gmail dot com>

vn_lock() is currently only used with the 'curthread' passed as argument.
Remove this argument and pass curthread directly to underlying
VOP_LOCK1() VFS method. This modify makes the code cleaner and in
particular remove an annoying dependence helping next lockmgr() cleanup.
KPI results, obviously, changed.

Manpage and FreeBSD_version will be updated through further commits.

As a side note, would be valuable to say that next commits will address
a similar cleanup about VFS methods, in particular vop_lock1 and
vop_unlock.

Tested by: Diego Sardina <siarodx at gmail dot com>,
Andrea Di Pasquale <whyx dot it at gmail dot com>

Trimm out now unused option LK_EXCLUPGRADE from the lockmgr namespace.
This option just adds complexity and the new implementation no longer
will support it, so axing it now that it is unused is probabilly the
better idea.

FreeBSD version is bumped in order to reflect the KPI breakage introduced
by this patch.

In the ports tree, kris found that only old OSKit code uses it, but as
it is thought to work only on 2.x kernels serie, version bumping will
solve any problem.

Added whiteout behavior option. ``-o whiteout=always'' is default mode
(it is established practice) and ``-o whiteout=whenneeded'' is less
disk-space using mode especially for resource restricted environments
like embedded environments. (Contributed by Ed Schouten. Thanks)

Submitted by: Masanori Ozawa <ozawa@ongs.co.jp> (unionfs developer)
Reviewed by: jeff, kensmith
Approved by: re (kensmith)
MFC after: 1 week

Added NULL check code pointed out by Coverity. (via Stanislav
Sedov. Thanks)

Submitted by: Masanori Ozawa <ozawa@ongs.co.jp> (unionfs developer)
Reviewed by: jeff, kensmith
Approved by: re (kensmith)
MFC after: 1 week

- It has been become MPSAFE.
- Fixed lock panic issue under MPSAFE.
- Fixed panic issue whenever it locks vnode with reclaim.
- Fixed lock implementations not conforming to vnode_if.src style.

Submitted by: Masanori Ozawa <ozawa@ongs.co.jp> (unionfs developer)
Reviewed by: jeff, kensmith
Approved by: re (kensmith)
MFC after: 1 week

Fixed vnode unlock/vrele untreated issues whenever errors have
occurred during some treatments.

Submitted by: Masanori Ozawa <ozawa@ongs.co.jp> (unionfs developer)
Reviewed by: jeff, kensmith
Approved by: re (kensmith)
MFC after: 1 week

- Added support for vfs_cache on unionfs. As a result, you can use
applications that use procfs on unionfs.
- Removed unionfs internal cache mechanism because it has
vfs_cache support instead. As a result, it just simplified code of
unionfs.
- Fixed kern/111262 issue.

Submitted by: Masanori Ozawa <ozawa@ongs.co.jp> (unionfs developer)
Reviewed by: jeff, kensmith
Approved by: re (kensmith)
MFC after: 1 week

Added treatments to prevent readdir infinity loop using with Linux binary
compatibility feature.

Submitted by: Masanori Ozawa <ozawa@ongs.co.jp> (unionfs developer)
Reviewed by: jeff, kensmith
Approved by: re (kensmith)
MFC after: 1 week

Changed it frees unneeded memory ASAP.

Submitted by: Masanori Ozawa <ozawa@ongs.co.jp> (unionfs developer)
Reviewed by: jeff, kensmith
Approved by: re (kensmith)
MFC after: 1 week

Revert UF_OPENING workaround for CURRENT.
Change the VOP_OPEN(), vn_open() vnode operation and d_fdopen() cdev operation
argument from being file descriptor index into the pointer to struct file.

Proposed and reviewed by: jhb
Reviewed by: daichi (unionfs)
Approved by: re (kensmith)

Since renaming of vop_lock to _vop_lock, pre- and post-condition
function calls are no more generated for vop_lock.
Rename _vop_lock to vop_lock1 to satisfy tools/vnode_if.awk assumption
about vop naming conventions. This restores pre/post-condition calls.

Move vnode-to-file-handle translation from vfs_vptofh to vop_vptofh method.
This way we may support multiple structures in v_data vnode field within
one file system without using black magic.

Vnode-to-file-handle should be VOP in the first place, but was made VFS
operation to keep interface as compatible as possible with SUN's VFS.
BTW. Now Solaris also implements vnode-to-file-handle as VOP operation.

VFS_VPTOFH() was left for API backward compatibility, but is marked for
removal before 8.0-RELEASE.

Approved by: mckusick
Discussed with: many (on IRC)
Tested with: ufs, msdosfs, cd9660, nullfs and zfs

Eliminate ASSERT_VOP_ELOCKED panics when doing mkdir or symlink when
sysctl vfs.lookup_shared=1.

Submitted by: daichi, Masanori OZAWA <ozawa ongs co jp>

Add locking around calls to unionfs_get_node_status()
in unionfs_ioctl() and unionfs_poll().

Submitted by: daichi, Masanori OZAWA <ozawa@ongs.co.jp>
Prompted by: kris

In unionfs_readdir(), prevent a possible NULL dereference.

CID: 1667
Found by: Coverity Prevent (tm)

Add missing includes for <sys/buf.h> and <sys/bio.h>.

Many, many thanks to Masanori OZAWA <ozawa@ongs.co.jp>
and Daichi GOTO <daichi@FreeBSD.org> for submitting this
major rewrite of unionfs. This rewrite was done to
try to solve many of the longstanding crashing and locking
issues in the existing unionfs implementation. This
implementation also adds a 'MASQUERADE mode', which allows
the user to set different user, group, and file permission
modes in the upper layer.

Submitted by: daichi, Masanori OZAWA
Reviewed by: rodrigc (modified for minor style issues)

Remove unneeded mac.h include.

MFC after: 3 days

- Fix typo.

Approved by: ssouhlal
MFC after: 1 week

- Set the v_object pointer after a successful VOP_OPEN(). This isn't a
perfect solution as the lower vm object can change at unpredictable times
if our lower vp happens to be on another unionfs, etc.

Submitted by: Oleg Sharoiko <os@rsu.ru>

- Change all filesystems and vfs_cache to relock the dvp once the child is
locked in the ISDOTDOT case. Se vfs_lookup.c r1.79 for details.

Sponsored by: Isilon Systems, Inc.

- Fix union's assumptions about when the dvp is unlocked. It is only
unlocked in the ISDOTDOT case now, not for all !ISLASTCN lookups.

- Remove unnecessary LOCKPARENT manipulation.

Sponsored by: Isilon Systems, Inc.

- 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.

- The VI_DOOMED flag now signals the end of a vnode's relationship with
the filesystem. Check that rather than VI_XLOCK.
- VOP_INACTIVE should no longer drop the vnode lock.
- The vnode lock is required around calls to vrecycle() and vgone().

Sponsored by: Isilon Systems, Inc.

Deimplement vop_destroyvobject()

Take VOP_GETVOBJECT() out to pasture. We use the direct pointer now.

Kill VOP_CREATEVOBJECT(), it is now the responsibility of the filesystem
for a given vnode to create a vnode_pager object if one is needed.

Don't call VOP_CREATEVOBJECT(), it's the responsibility of the
filesystem which owns the vnode.

Kill the VV_OBJBUF and test the v_object for NULL instead.

Whitespace in vop_vector{} initializations.

Ditch vfs_object_create() and make the callers call VOP_CREATEVOBJECT()
directly.

Change the generated VOP_ macro implementations to improve type checking
and KASSERT coverage.

After this check there is only one "nasty" cast in this code but there
is a KASSERT to protect against the wrong argument structure behind
that cast.

Un-inlining the meat of VOP_FOO() saves 35kB of text segment on a typical
kernel with no change in performance.

We also now run the checking and tracing on VOP's which have been layered
by nullfs, umapfs, deadfs or unionfs.

Add new (non-inline) VOP_FOO_AP() functions which take a "struct
foo_args" argument and does everything the VOP_FOO() macros
used to do with checks and debugging code.

Add KASSERT to VOP_FOO_AP() check for argument type being
correct.

Slim down VOP_FOO() inline functions to just stuff arguments
into the struct foo_args and call VOP_FOO_AP().

Put function pointer to VOP_FOO_AP() into vop_foo_desc structure
and make VCALL() use it instead of the current offsetoff() hack.

Retire vcall() which implemented the offsetoff()

Make deadfs and unionfs use VOP_FOO_AP() calls instead of
VCALL(), we know which specific call we want already.

Remove unneeded arguments to VCALL() in nullfs and umapfs bypass
functions.

Remove unused vdesc_offset and VOFFSET().

Generally improve style/readability of the generated code.

Remove the unused credential argument from VOP_FSYNC() and VFS_SYNC().

I'm not sure why a credential was added to these in the first place, it is
not used anywhere and it doesn't make much sense:

The credentials for syncing a file (ability to write to the
file) should be checked at the system call level.

Credentials for syncing one or more filesystems ("none")
should be checked at the system call level as well.

If the filesystem implementation needs a particular credential
to carry out the syncing it would logically have to the
cached mount credential, or a credential cached along with
any delayed write data.

Discussed with: rwatson

/* -> /*- for copyright notices, minor format tweaks as necessary

Back when VOP_* was introduced, we did not have new-style struct
initializations but we did have lofty goals and big ideals.

Adjust to more contemporary circumstances and gain type checking.

Replace the entire vop_t frobbing thing with properly typed
structures. The only casualty is that we can not add a new
VOP_ method with a loadable module. History has not given
us reason to belive this would ever be feasible in the the
first place.

Eliminate in toto VOCALL(), vop_t, VNODEOP_SET() etc.

Give coda correct prototypes and function definitions for
all vop_()s.

Generate a bit more data from the vnode_if.src file: a
struct vop_vector and protype typedefs for all vop methods.

Add a new vop_bypass() and make vop_default be a pointer
to another struct vop_vector.

Remove a lot of vfs_init since vop_vector is ready to use
from the compiler.

Cast various vop_mumble() to void * with uppercase name,
for instance VOP_PANIC, VOP_NULL etc.

Implement VCALL() by making vdesc_offset the offsetof() the
relevant function pointer in vop_vector. This is disgusting
but since the code is generated by a script comparatively
safe. The alternative for nullfs etc. would be much worse.

Fix up all vnode method vectors to remove casts so they
become typesafe. (The bulk of this is generated by scripts)

Correctly prototype union_write with vop_write_t, not vop_read_t.

Mechanically change prototypes for vnode operations to use the new typedefs.

VOP_REVOKE() is only ever for VCHR vnodes, so unionfs does not
need a vop_revoke() method.

Eliminate unnecessary KASSERTs.

Don't use bp->b_vp in VOP_STRATEGY: the vnode is passed in as an argument.

Minor Bug fix. Some file was not translated.

Fix unionfs problems when a directory is mounted on other directory
with different file systems. This may cause ill things
with my previous fix. Now it translate fsid of direct child of
mount point directory only.

Pointed out by: Uwe Doering

Fix a problem when you try to mount a directory on another directory
belongs to the same filesystem. In this problem, getcwd(3) will fail.

I found the problem two years ago and I have forgotten to merge.

http://docs.FreeBSD.org/cgi/mid.cgi?200202251435.XAA91094

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.

Remove advertising clause from University of California Regent's
license, per letter dated July 22, 1999 and email from Peter Wemm,
Alan Cox and Robert Watson.

Approved by: core, peter, alc, rwatson

Do not allow operations which cause known file-system corruption.

Fix an upper-vnode leak created in revision 1.52. When an upper-layer
file has been removed, it should be purged from the cache, but it need
not be removed from the directory stack causing corruption; instead,
it will simply be removed once the last references and holds on it
are dropped at the end of the unlink/rmdir system calls, and the
normal !UN_CACHED VOP_INACTIVE() handler for unionfs finishes it off.

This is easily reproduced by repeated "echo >file; rm file" on a
unionfs mount. Strangely, "echo -n >file; rm file" didn't make
it happen.

Pass ACL, extended attribute and MAC vnode ops down the vnode stack.

- A sanity check in unionfs verifies that lookups of '.' return the
vnode of the parent. However, this check should not be performed if
the lookup failed. This change should fix "union_lookup returning
. not same as startdir" panics people were seeing. The bug was
introduced by an incomplete import of a NetBSD delta in rev 1.38.
- Move the aforementioned check out from DIAGNOSTIC. Performance
is the least of our unionfs worries.
- Minor reorganization.

PR: 53004
MFC after: 1 week

Add a "int fd" argument to VOP_OPEN() which in the future will
contain the filedescriptor number on opens from userland.

The index is used rather than a "struct file *" since it conveys a bit
more information, which may be useful to in particular fdescfs and /dev/fd/*

For now pass -1 all over the place.

Add the same KASSERT to all VOP_STRATEGY and VOP_SPECSTRATEGY implementations
to check that the buffer points to the correct vnode.

Fix some style problems, some of which are old, some new, and some
inherited from UFS.

Requested by: bde, njl

If someone tries to mount a union filesystem with another unionfs as
the upper layer, fail gracefully instead of panicing.

MFC after: 3 days

Factor out the process of freeing ``directory caches'', which unionfs
directory vnodes use to refer to their constituent vnodes, into
union_dircache_free(). Also s/union_dircache/union_dircache_get/ and
tweak the structure of union_dircache_r().

MFC after: 3 days

Finish cleanup of vprint() which was begun with changing v_tag to a string.
Remove extraneous uses of vop_null, instead defering to the default op.
Rename vnode type "vfs" to the more descriptive "syncer".
Fix formatting for various filesystems that use vop_print.

Since Jeffr made the std* functions the default in rev 1.63 of
kern/vfs_defaults.c it is wrong for the individual filesystems to use
the std* functions as that prevents override of the default.

Found by: src/tools/tools/vop_table

Fix comments and one resulting code confusion about the type of the
"command" argument to VOP_IOCTL.

Spotted by: FlexeLint.

Regularize the vop_stdlock'ing protocol across all the filesystems
that use it. Specifically, vop_stdlock uses the lock pointed to by
vp->v_vnlock. By default, getnewvnode sets up vp->v_vnlock to
reference vp->v_lock. Filesystems that wish to use the default
do not need to allocate a lock at the front of their node structure
(as some still did) or do a lockinit. They can simply start using
vn_lock/VOP_UNLOCK. Filesystems that wish to manage their own locks,
but still use the vop_stdlock functions (such as nullfs) can simply
replace vp->v_vnlock with a pointer to the lock that they wish to
have used for the vnode. Such filesystems are responsible for
setting the vp->v_vnlock back to the default in their vop_reclaim
routine (e.g., vp->v_vnlock = &vp->v_lock).

In theory, this set of changes cleans up the existing filesystem
lock interface and should have no function change to the existing
locking scheme.

Sponsored by: DARPA & NAI Labs.

- Use vrefcnt() where it is safe to do so instead of doing direct and
unlocked accesses to v_usecount.
- Lock access to the buf lists in the various sync routines. interlock
locking could be avoided almost entirely in leaf filesystems if the
fsync function had a generic helper.

Fix misspellings, capitalization, and punctuation in comments. Minor
comment phrasing and style changes.

VOP_FSYNC() requires that it's vnode argument be locked, which nfs_link()
wasn't doing. Rather than just lock and unlock the vnode around the call
to VOP_FSYNC(), implement rwatson's suggestion to lock the file vnode
in kern_link() before calling VOP_LINK(), since the other filesystems
also locked the file vnode right away in their link methods. Remove the
locking and and unlocking from the leaf filesystem link methods.

Reviewed by: rwatson, bde (except for the unionfs_link() changes)

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)

- Replace v_flag with v_iflag and v_vflag
- v_vflag is protected by the vnode lock and is used when synchronization
with VOP calls is needed.
- v_iflag is protected by interlock and is used for dealing with vnode
management issues. These flags include X/O LOCK, FREE, DOOMED, etc.
- All accesses to v_iflag and v_vflag have either been locked or marked with
mp_fixme's.
- Many ASSERT_VOP_LOCKED calls have been added where the locking was not
clear.
- Many functions in vfs_subr.c were restructured to provide for stronger
locking.

Idea stolen from: BSD/OS

Remove __P.

Don't even think about using v_id for magic tricks, v_id is giving
us enough trouble as it is for SMPng.

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

- FDESC, FIFO, NULL, PORTAL, PROC, UMAP and UNION file
systems were repo-copied from sys/miscfs to sys/fs.

- Renamed the following file systems and their modules:
fdesc -> fdescfs, portal -> portalfs, union -> unionfs.

- Renamed corresponding kernel options:
FDESC -> FDESCFS, PORTAL -> PORTALFS, UNION -> UNIONFS.

- Install header files for the above file systems.

- Removed bogus -I${.CURDIR}/../../sys CFLAGS from userland
Makefiles.

Currently there is no way to tell if write operation invoked via
vn_start_write() on the given vnode will be successful. VOP_LEASE() may
help to solve this problem, but its return value ignored nearly everywhere.
For now just assume that the missing upper layer on write means insufficient
access rights (which is correct for most cases).

VOP getwritemount() can be invoked on vnodes with VFREE flag set (used in
snapshots code). At this point upper vp may not exist.

Use vop_*vobject() VOPs to get reference to VM object from upper or lower fs.

Implement vop_std{get|put}pages() and add them to the default vop[].

Un-copy&paste all the VOP_{GET|PUT}PAGES() functions which do nothing but
the default.

Add a vop_stdbmap(), and make it part of the default vop vector.

Make 7 filesystems which don't really know about VOP_BMAP rely
on the default vector, rather than more or less complete local
vop_nopbmap() implementations.

Fix breakage unconvered by LINT - dont refer to undefined variables in
KASSERT()

Don't compile a dead variable declaration.

Give vop_mmap an untimely death. The opportunity to give it a timely
death timed out in 1996.

Move suser() and suser_xxx() prototypes and a related #define from
<sys/proc.h> to <sys/systm.h>.

Correctly document the #includes needed in the manpage.

Add one now needed #include of <sys/systm.h>.
Remove the consequent 48 unused #includes of <sys/proc.h>.

Add snapshots to the fast filesystem. Most of the changes support
the gating of system calls that cause modifications to the underlying
filesystem. The gating can be enabled by any filesystem that needs
to consistently suspend operations by adding the vop_stdgetwritemount
to their set of vnops. Once gating is enabled, the function
vfs_write_suspend stops all new write operations to a filesystem,
allows any filesystem modifying system calls already in progress
to complete, then sync's the filesystem to disk and returns. The
function vfs_write_resume allows the suspended write operations to
begin again. Gating is not added by default for all filesystems as
for SMP systems it adds two extra locks to such critical kernel
paths as the write system call. Thus, gating should only be added
as needed.

Details on the use and current status of snapshots in FFS can be
found in /sys/ufs/ffs/README.snapshot so for brevity and timelyness
is not included here. Unless and until you create a snapshot file,
these changes should have no effect on your system (famous last words).

Separate the struct bio related stuff out of <sys/buf.h> into
<sys/bio.h>.

<sys/bio.h> is now a prerequisite for <sys/buf.h> but it shall
not be made a nested include according to bdes teachings on the
subject of nested includes.

Diskdrivers and similar stuff below specfs::strategy() should no
longer need to include <sys/buf.> unless they need caching of data.

Still a few bogus uses of struct buf to track down.

Repocopy by: peter

Remove B_READ, B_WRITE and B_FREEBUF and replace them with a new
field in struct buf: b_iocmd. The b_iocmd is enforced to have
exactly one bit set.

B_WRITE was bogusly defined as zero giving rise to obvious coding
mistakes.

Also eliminate the redundant struct buf flag B_CALL, it can just
as efficiently be done by comparing b_iodone to NULL.

Should you get a panic or drop into the debugger, complaining about
"b_iocmd", don't continue. It is likely to write on your disk
where it should have been reading.

This change is a step in the direction towards a stackable BIO capability.

A lot of this patch were machine generated (Thanks to style(9) compliance!)

Vinum users: Greg has not had time to test this yet, be careful.

Introduce NDFREE (and remove VOP_ABORTOP)

Lock reporting and assertion changes.
* lockstatus() and VOP_ISLOCKED() gets a new process argument and a new
return value: LK_EXCLOTHER, when the lock is held exclusively by another
process.
* The ASSERT_VOP_(UN)LOCKED family is extended to use what this gives them
* Extend the vnode_if.src format to allow more exact specification than
locked/unlocked.

This commit should not do any semantic changes unless you are using
DEBUG_VFS_LOCKS.

Discussed with: grog, mch, peter, phk
Reviewed by: peter

Remove unused #includes.

Obtained from: http://bogon.freebsd.dk/include

Fix an unused variable warning.

Remove WILLRELE from VOP_SYMLINK

Note: Previous commit to these files (except coda_vnops and devfs_vnops)
that claimed to remove WILLRELE from VOP_RENAME actually removed it from
VOP_MKNOD.

Remove WILLRELE from VOP_RENAME

useracc() the prequel:

Merge the contents (less some trivial bordering the silly comments)
of <vm/vm_prot.h> and <vm/vm_inherit.h> into <vm/vm.h>. This puts
the #defines for the vm_inherit_t and vm_prot_t types next to their
typedefs.

This paves the road for the commit to follow shortly: change
useracc() to use VM_PROT_{READ|WRITE} rather than B_{READ|WRITE}
as argument.

Make sure file after VOP_OPEN is VMIO'd when transfering control from
a lower layer to an upper layer. I'm not sure how necessary this is
for reading.

Fix bug in union_lookup() (note: there are probably still several bugs
in union_lookup()). This one set lerror as a side effect without
setting lowervp, causing copyup code further on down to crash on a null
lowervp pointer. Changed the side effect to use a temporary variable
instead.

This is a major fixup of unionfs. At least 30 serious bugs have been
fixed (many due to changing semantics in other parts of the kernel and not
the original author's fault), including one critical one: unionfs could
cause UFS corruption in the fronting store due to calling VOP_OPEN for
writing without turning on vmio for the UFS vnode.

Most of the bugs were related to semantics changes in VOP calls, lock
ordering problems (causing deadlocks), improper handling of a read-only
backing store (such as an NFS mount), improper referencing and locking
of vnodes, not using real struct locks for vnode locking, not using
recursive locks when accessing the fronting store, and things like that.

New functionality has been added: unionfs now has mmap() support, but
only partially tested, and rename has been enhanced considerably.

There are still some things that unionfs cannot do. You cannot
rename a directory without confusing unionfs, and there are issues
with softlinks, hardlinks, and special files. unionfs mostly doesn't
understand them (and never did).

There are probably still panic situations, but hopefully no where near
as many as before this commit.

The unionfs in this commit has been tested overlayed on /usr/src
(backing /usr/src being a read-only NFS mount, fronting /usr/src being
a local filesystem). kernel builds have been tested, buildworld is
undergoing testing. More testing is necessary.

$Id$ -> $FreeBSD$

Make sure that stat(2) and friends always return a valid st_dev field.

Pseudo-FS need not fill in the va_fsid anymore, the syscall code
will use the first half of the fsid, which now looks like a udev_t
with major 255.

Add a vnode argument to VOP_BWRITE to get rid of the last vnode
operator special case. Delete special case code from vnode_if.sh,
vnode_if.src, umap_vnops.c, and null_vnops.c.

Fix warnings in preparation for adding -Wall -Wcast-qual to the
kernel compile

Cleanup uninitialized-possibly-used (but really not) warnings

VOP_STRATEGY grows an (struct vnode *) argument
as the value in b_vp is often not really what you want.
(and needs to be frobbed). more cleanups will follow this.
Reviewed by: Bruce Evans <bde@freebsd.org>

In the words of the submitter:

---------
Make callers of namei() responsible for releasing references or locks
instead of having the underlying filesystems do it. This eliminates
redundancy in all terminal filesystems and makes it possible for stacked
transport layers such as umapfs or nullfs to operate correctly.

Quality testing was done with testvn, and lat_fs from the lmbench suite.

Some NFS client testing courtesy of Patrik Kudo.

vop_mknod and vop_symlink still release the returned vpp. vop_rename
still releases 4 vnode arguments before it returns. These remaining cases
will be corrected in the next set of patches.
---------

Submitted by: Michael Hancock <michaelh@cet.co.jp>

If lowervp is NULLVP, vap was clobbered.

Submitted by: Naofumi Honda <honda@Kururu.math.sci.hokudai.ac.jp>
Obtained from: NetBSD/pc98

Deleted KLOCK-hack.

Undo UN_KLOCK hack except union_allocvp(). Now, vput() doesn't lock
the vnode.

Back out DIAGNOSTIC changes.

Workarround for DIAGNOSTIC kernel's panic in union_lookup().
Union_removed_upper() clobbers cache when file is removed.
Upper vp will be removed by union_reclaim().

Turn DIAGNOSTIC into a new-style option.

Delete unused code in union_fsync().

- Move SETKLOC and CLEARKLOCK macros into uion.h.
- Set UN_ULOCK in union_lock() when UN_KLOCK is set. Caller expects
that vnode is locked correctly, and may call another function which
expects locked vnode and may unlock the vnode.
- Do not assume the behavior of inside functions in FreeBSD's
vfs_suber.c is same as 4.4BSD-Lite2. Vnode may be locked in
vget() even though flag is zero. (Locked vnode is, of course,
unlocked before returning from vget.)

Workarround for locking violation while recycling vnode which union fs
used in freelist.

Improve and revise fixes for locking violation.

Obtained from: NetBSD/pc98

VFS interior redecoration.

Rename vn_default_error to vop_defaultop all over the place.
Move vn_bwrite from vfs_bio.c to vfs_default.c and call it vop_stdbwrite.
Use vop_null instead of nullop.
Move vop_nopoll from vfs_subr.c to vfs_default.c
Move vop_sharedlock from vfs_subr.c to vfs_default.c
Move vop_nolock from vfs_subr.c to vfs_default.c
Move vop_nounlock from vfs_subr.c to vfs_default.c
Move vop_noislocked from vfs_subr.c to vfs_default.c
Use vop_ebadf instead of *_ebadf.
Add vop_defaultop for getpages on master vnode in MFS.

Another VFS cleanup "kilo commit"

1. Remove VOP_UPDATE, it is (also) an UFS/{FFS,LFS,EXT2FS,MFS}
intereface function, and now lives in the ufsmount structure.

2. Remove VOP_SEEK, it was unused.

3. Add mode default vops:

VOP_ADVLOCK vop_einval
VOP_CLOSE vop_null
VOP_FSYNC vop_null
VOP_IOCTL vop_enotty
VOP_MMAP vop_einval
VOP_OPEN vop_null
VOP_PATHCONF vop_einval
VOP_READLINK vop_einval
VOP_REALLOCBLKS vop_eopnotsupp

And remove identical functionality from filesystems

4. Add vop_stdpathconf, which returns the canonical stuff. Use
it in the filesystems. (XXX: It's probably wrong that specfs
and fifofs sets this vop, shouldn't it come from the "host"
filesystem, for instance ufs or cd9660 ?)

5. Try to make system wide VOP functions have vop_* names.

6. Initialize the um_* vectors in LFS.

(Recompile your LKMS!!!)

Hmm, realign the vnops into two columns.

Stylistic overhaul of vnops tables.
1. Remove comment stating the blatantly obvious.
2. Align in two columns.
3. Sort all but the default element alphabetically.
4. Remove XXX comments pointing out entries not needed.

Convert select -> poll.
Delete 'always succeed' select/poll handlers, replaced with generic call.
Flag missing vnode op table entries.

Staticized.

Support read-only mount.

Removed unused #includes.

Added DIAGNOSTIC routine to test inconsistency of vnode when cnp
points `.'.

Obtained from: NetBSD

Deleted unused code which adjust UN_UNLOCK flag.

Backed out part of previous change. The example of -b mount in
manpage works again.

Fixed vnode corruption by undefined case in union_lookup(). When
uerror == 0 && lerror == EACCES, lowervp == NULLVP and union_allocvp
doesn't find existing union node and new union node is created.

Sicne it is dificult to cover all the case, union_lookup always
returns when union_lookup1() returns EACCES.

Submitted by: Naofumi Honda <honda@Kururu.math.sci.hokudai.ac.jp>
Obtained from: NetBSD/pc98

1. Added cast and parenthesis in block size calculaion in
union_statfs().
2. staticized union vops.

Submitted by: Doug Rabson <dfr@nlsystems.com>

Fixed panic message in union_lock(): union_link --> union_lock.

Access correct union mount point in union_access. Old vnode is saved
in savedvp variable and it is used for the argument of
MOUNTTOUNIONMOUNT(). I didn't realize ap->a_vp is modified before
MOUNTTOUNIONMOUNT(), so the change by revision 1.22 is incorrect.

Revised fix for locking violation when unionfs calls vput with
UN_KLOCK flag.

When UN_KLOCK is set, VOP_UNLOCK should keep uppervp locked and clear
UN_ULOCK flag. To do this, when UN_KLOCK is set, (1) union_unlock
clears UN_ULOCK and does not clear UN_KLOCK, (2) union_lock() does not
access uppervp and does not clear UN_KLOCK, and (3) callers of
vput/VOP_UNLOCK should clear UN_KLOCK. For example, vput becomes:

SETKLOCK(union_node);
vput(vnode);
CLEARKLOCK(union_node);

where SETKLOCK macro sets UN_KLOCK and CLEARKLOCK macro clears
UN_KLOCK.

Undo 1.29.

Do nothing instead of adjusting un_flags when (uppervp is locked) &&
(UN_ULOCK is not set) in union_lock. This condition may indicate
race. DIAGNOSTIC kernel still panic here.

Do not clear UN_ULOCK in certain case.

Our vput calls vm_object_deallocate() --> vm_object_terminate(). The
vm_object_terminate() calls vn_lock(), since UN_LOCKED has been
already cleared in union_unlock(). Then, union_lock locks upper vnode
when UN_ULOCK is not set. The upper vnode is not unlocked when
UN_KLOCK is set in union_unlock(), thus, union_lock tries to lock
locked vnode and we get panic.

Dirty change in union_lock(). Sometimes upper vnode is locked without
UN_ULOCK flag. This shows a locking violation but I couldn't find the
reason UN_ULOCK is not set or upper vnode is not unlocked. I added
the code that detect this case and adjust un_flags. DIAGNOSTIC kernel
doesn't adjust un_flags, but just panic here to help debug by kernel
hackers.

Replace VOP_LOCK with vn_lock.

Undo previous commit to avoid panic, and fix order of argument of
VOP_LINK(). The reason of strange behavior was wrong order of the
argument, that is, the operation

# ln foo bar

in a union fs tried to do

# ln bar foo

in ufs layer.

Now we can make a link in a union fs.

Quick-hack to avoid `lock against myself' panic. It is not the real
fix!

The ufs_link() assumes that vnode is not unlocked and tries to lock it
in certain case. Because union_link calls VOP_LINK after locking vnode,
vn_lock in ufs_link causes above panic.

Currently, I don't know the real fix for a locking violation in
union_link, but I think it is important to avoid panic.

A vnode is unlocked before calling VOP_LINK and is locked after it if
the vnode is not union fs. Even though panic went away, the process
that access the union fs in which link was made will hang-up.

Hang-up can be easily reproduced by following operation:

mount -t union a b
cd b
ln foo bar
ls

Fix locking violation when accessing `..'.
Obtained from: NetBSD

Access correct union mount point in union_access.

The function union_fsync tries to lock overlaying vnode object when
dolock is not set (that is, targetvp == overlaying vnode object).
Current code use FIXUP macro to do this, and never unlocks overlaying
vnode object in union_fsync. So, the vnode object will be locked
twice and never unlocked.

PR: 3271
Submitted by: kato

Don't #include <sys/fcntl.h> in <sys/file.h> if KERNEL is defined.
Fixed everything that depended on getting fcntl.h stuff from the wrong
place. Most things don't depend on file.h stuff at all.

Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.

Restored #include of <sys/kernel.h> so that this compiles again.

Add function protypes for the new Lite2 unionfs functions.

This is the kernel Lite/2 commit. There are some requisite userland
changes, so don't expect to be able to run the kernel as-is (very well)
without the appropriate Lite/2 userland changes.

The system boots and can mount UFS filesystems.

Untested: ext2fs, msdosfs, NFS
Known problems: Incorrect Berkeley ID strings in some files.
Mount_std mounts will not work until the getfsent
library routine is changed.

Reviewed by: various people
Submitted by: Jeffery Hsu <hsu@freebsd.org>

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

Added prototypes.

Removed some unnecessary #includes.

Introduced a type `vop_t' for vnode operation functions and used
it 1138 times (:-() in casts and a few more times in declarations.
This change is null for the i386.

The type has to be `typedef int vop_t(void *)' and not `typedef
int vop_t()' because `gcc -Wstrict-prototypes' warns about the
latter. Since vnode op functions are called with args of different
(struct pointer) types, neither of these function types is any use
for type checking of the arg, so it would be preferable not to use
the complete function type, especially since using the complete
type requires adding 1138 casts to avoid compiler warnings and
another 40+ casts to reverse the function pointer conversions before
calling the functions.

Added VOP_GETPAGES/VOP_PUTPAGES and also the "backwards" block count
for VOP_BMAP. Updated affected filesystems...

The `cred' and `proc' args were missing for some VOP_OPEN() and VOP_CLOSE()
calls.

Found by: gcc -Wstrict-prototypes after I supplied some of the 5000+
missing prototypes. Now I have 9000+ lines of warnings and errors
about bogus conversions of function pointers.

Removed my special-case hack for VOP_LINK and fixed the problem with the
wrong vp's ops vector being used by changing the VOP_LINK's argument order.
The special-case hack doesn't go far enough and breaks the generic
bypass routine used in some non-leaf filesystems. Pointed out by Kirk
McKusick.

Fixed VOP_LINK argument order botch.

From tim@cs.city.ac.uk (Tim Wilkinson):

Find enclosed a short bugfix to get the union filesystem up and running
in FreeBSD-current. We don't think we've got all the problems yet but
these fixes sort out the major ones (which mostly concert bad locking
of vnodes), no doubt we'll post others as necessary. Known problems
include the inability of the umount command (not the system call) to unmount
unions in certain circumstances (this is due the way "realpath" works),
and the failure of direntries to always get all available files in
unioned subdirectories. We are, as they say, working on it.

Submitted by: tim@cs.city.ac.uk (Tim Wilkinson)

Cosmetics. reduce the noise from gcc -Wall.

Use tsleep() rather than sleep so that 'ps' is more informative about
the wait.

Fix a few niggling little bugs:

- set args->lkm_offset correctly so that VFS modules can be unloaded
- initialize _fs_vfsops.vfc_refcount correctly so that VFS modules can
be unloaded
- include kernel.h in a few placves to get the correct definition of DATA_SET

Implemented loadable VFS modules, and made most existing filesystems
loadable. (NFS is a notable exception.)

Added $Id$

The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch.

Reviewed by: Rodney W. Grimes
Submitted by: John Dyson and David Greenman

BSD 4.4 Lite Kernel Sources